Historical drought patterns over Canada and their teleconnections with large-scale climate signals

NASA Astrophysics Data System (ADS)

Asong, Zilefac Elvis; Wheater, Howard Simon; Bonsal, Barrie; Razavi, Saman; Kurkute, Sopan

2018-06-01

Drought is a recurring extreme climate event and among the most costly natural disasters in the world. This is particularly true over Canada, where drought is both a frequent and damaging phenomenon with impacts on regional water resources, agriculture, industry, aquatic ecosystems, and health. However, nationwide drought assessments are currently lacking and impacted by limited ground-based observations. This study provides a comprehensive analysis of historical droughts over the whole of Canada, including the role of large-scale teleconnections. Drought events are characterized by the Standardized Precipitation Evapotranspiration Index (SPEI) over various temporal scales (1, 3, 6, and 12 consecutive months, 6 months from April to September, and 12 months from October to September) applied to different gridded monthly data sets for the period 1950-2013. The Mann-Kendall test, rotated empirical orthogonal function, continuous wavelet transform, and wavelet coherence analyses are used, respectively, to investigate the trend, spatio-temporal patterns, periodicity, and teleconnectivity of drought events. Results indicate that southern (northern) parts of the country experienced significant trends towards drier (wetter) conditions although substantial variability exists. Two spatially well-defined regions with different temporal evolution of droughts were identified - the Canadian Prairies and northern central Canada. The analyses also revealed the presence of a dominant periodicity of between 8 and 32 months in the Prairie region and between 8 and 40 months in the northern central region. These cycles of low-frequency variability are found to be associated principally with the Pacific-North American (PNA) and Multivariate El Niño/Southern Oscillation Index (MEI) relative to other considered large-scale climate indices. This study is the first of its kind to identify dominant periodicities in drought variability over the whole of Canada in terms of when the drought events occur, their duration, and how often they occur.

Impact of the basic state and MJO representation on MJO Pacific teleconnections in GCMs

NASA Astrophysics Data System (ADS)

Henderson, S. A.; Maloney, E. D.; Son, S. W.

2017-12-01

Teleconnection patterns induced by the Madden-Julian Oscillation (MJO) are known to significantly alter extratropical weather and climate patterns. However, accurate MJO representation has been difficult for many General Circulation Models (GCMs). Furthermore, many GCMs contain large basic state biases. These issues present challenges to the simulation of MJO teleconnections and, in turn, their associated extratropical impacts. This study examines the impacts of basic state quality and MJO representation on the quality of MJO teleconnection patterns in GCMs from phase 5 of the Coupled Model Intercomparison Project (CMIP5). Results suggest that GCMs assessed to have a good MJO but with large basic state biases have similarly low skill in reproducing MJO teleconnections as GCMs with poor MJO representation. In the good MJO models examined, poor teleconnection quality is associated with large errors in the zonal extent of the Pacific subtropical jet. Whereas the horizontal structure of MJO heating in the Indo-Pacific region is found to have modest impacts on the teleconnection patterns, results suggest that MJO heating east of the dateline can alter the teleconnection pattern characteristics over North America. These findings suggest that in order to accurately simulate the MJO teleconnection patterns and associated extratropical impacts, both the MJO and the basic state must be well represented.

Seasonal Storminess in the North Pacific, Bering Sea, and Alaskan Regions

NASA Astrophysics Data System (ADS)

Shippee, N. J.; Atkinson, D. E.; Walsh, J. E.; Partain, J.; Gottschalck, J.; Marra, J.

2012-12-01

Annually, extra-tropical cyclones present a high impact natural hazard to the North Pacific, Bering Sea, and Alaskan regions. In these regions, extensive subsistence and commercial fishing, new oil and gas field development, tourism, growing interest in and exploitation of new commercial shipping potential, and increasing military and Coast Guard activity, all represent potential parties impacted by storms in these waters. It is of interest to many parties to begin developing capacity to provide some indication of storm activity at a monthly- to seasonal-outlook (30 to 90 days) timeframe. Using storm track data from NOAA's Climate Prediction Center for the North Pacific and Alaskan region, an experimental seasonal storminess outlook product, using eigen-based methods similar to the operational seasonal temperature and precipitation products currently produced at NOAA CPC, has been created and tested in hindcast mode using predicted states of ENSO, the Pacific Decadal Oscillation (PDO), the Pacific-North American Pattern (PNA), and the Arctic Oscillation (AO). A sample of the seasonal storminess outlook product will be shown along with a discussion of the utility of individual teleconnection patterns in the generation of the product.

Large-Scale Atmospheric Teleconnection Patterns Associated with the Interannual Variability of Heatwaves in East Asia and Its Decadal Changes

NASA Astrophysics Data System (ADS)

Choi, N.; Lee, M. I.; Lim, Y. K.; Kim, K. M.

2017-12-01

Heatwave is an extreme hot weather event which accompanies fatal damage to human health. The heatwave has a strong relationship with the large-scale atmospheric teleconnection patterns. In this study, we examine the spatial pattern of heatwave in East Asia by using the EOF analysis and the relationship between heatwave frequency and large-scale atmospheric teleconnection patterns. We also separate the time scale of heatwave frequency as the time scale longer than a decade and the interannual time scale. The long-term variation of heatwave frequency in East Asia shows a linkage with the sea surface temperature (SST) variability over the North Atlantic with a decadal time scale (a.k.a. the Atlantic Multidecadal Oscillation; AMO). On the other hands, the interannual variation of heatwave frequency is linked with the two dominant spatial patterns associated with the large-scale teleconnection patterns mimicking the Scandinavian teleconnection (SCAND-like) pattern and the circumglobal teleconnection (CGT-like) pattern, respectively. It is highlighted that the interannual variation of heatwave frequency in East Asia shows a remarkable change after mid-1990s. While the heatwave frequency was mainly associated with the CGT-like pattern before mid-1990s, the SCAND-like pattern becomes the most dominant one after mid-1990s, making the CGT-like pattern as the second. This study implies that the large-scale atmospheric teleconnection patterns play a key role in developing heatwave events in East Asia. This study further discusses possible mechanisms for the decadal change in the linkage between heatwave frequency and the large-scale teleconnection patterns in East Asia such as early melting of snow cover and/or weakening of East Asian jet stream due to global warming.

Trends and Variability of the Outdoor Skating Season in Canada during 1951-2005

NASA Astrophysics Data System (ADS)

Damyanov, Nikolay Nikolaev

Climate change affects a range of human activities, including one of Canada's prime sources of entertainment: ice skating. Whether done recreationally or as hockey, its outdoor component is heavily dependent on weather and climate. Based on information obtained from public works officials from various Canadian cities, I have established a meteorological criterion for the initiation of an outdoor skating season (OSS) as the last day in a sequence of the first three consecutive fall/winter days with a maximum temperature below -5 °C. In addition, I derive a proxy of the OSS length, defined as the total number of days with a maximum temperature below -5 °C after the OSS start date and before the start of March. Using these filters, I have extracted the start dates and the lengths of the OSS for each year during the fifty-five year period 1951-2005 from a comprehensive daily temperature dataset (Vincent et al., 2002). For each station, I created time series of both the OSS start dates and OSS lengths, and calculated the magnitude, sign and statistical significance of the slopes of the best-fit lines to each time series. In order to establish a relationship of the OSS with large-scale climate patterns, I grouped stations into six climatic regions. Depending on location, I then tested each region for correlation with the Pacific North-American teleconnection pattern (PNA) or the North Atlantic Oscillation (NAO), using a composite analysis method. Lastly, I removed the signal due to these climate fluctuations from the OSS start date and length trends in order to determine how much of the variability was caused by these interannual climate oscillations. The results of the study indicate that most stations in British Columbia and southwest Alberta, as well as these in the southern Ontario/Quebc region have witnessed a progressively later onset of the OSS over time. The Prairies, northwest Canada, and some Maritime locales show the opposite trend, although the magnitudes of the slopes are smaller. Significance tests on the regression lines show that most of these trends are not significant at the 95% level. However, OSS start dates in western Canada are very well correlated with PNA patterns by happening later on the average whenever PNA is positive and more warm air is channeled towards the west coast; the OSS start dates in eastern Canada show a similar connection with the NAO. The OSS lengths exhibit different trends: five of the six regions show a decrease in OSS length with the only region having experienced a lengthening of the OSS being the Maritimes. The statistical significance of the OSS length slopes is much higher than that of OSS start slopes, and the correlation with the PNA or NAO is similar in both cases. After carrying out the last procedure (removal of the PNA and NAO signals from the OSS start date and length series), I found an increase in the new slopes and their significance for more than half of my geographic regions' OSS start date and length trends.

The relationship of extratropical outgoing longwave radiation to monthly geopotential teleconnection patterns

NASA Technical Reports Server (NTRS)

Charlock, Thomas P.; Bess, T. Dale; Smith, G. Louis; Rose, Fred G.

1990-01-01

The relationship between low frequency variations in extratropical fields of outgoing longwave radiation (OLR) and geopotential teleconnection patterns as determined by rotated principal components analysis of the NMC 500-mb heights is investigated in the Northern Hemisphere. The monthly broadband OLR is obtained from the Nimbus-6 and Nimbus-7 Wide-Field-Of-View radiometer record. Each of the main 500-mb teleconnection patterns has a characteristic signal in the OLR field for the month in which the 500-mb pattern occurs. The OLR signals mark cloud and diabatic heating events that are associated with the teleconnection patterns. A demonstration is given of correlation between extratropical monthly OLR and geopotential height. Coupled with the expected tropospheric response to radiation on monthly time scale. This demonstration stresses the importance of the radiation simulation in model studies of the low frequency variability of atmospheric circulation. The extratropical OLR does not appear to be a useful predictor for the 500-mb teleconnection patterns on a monthly time scale.

Can solar cycle modulate the ENSO effect on the Pacific/North American pattern?

NASA Astrophysics Data System (ADS)

Li, Delin; Xiao, Ziniu

2018-01-01

The ENSO effect on the Pacific/North American pattern (PNA) is well-known robust. Recent studies from observations and model simulations have reported that some important atmospheric circulation systems of extratropics are markedly modulated by the 11-year solar cycle. But less effort has been devoted to revealing the solar influence on the PNA. We thus hypothesize that the instability and uncertainty in the relationship between solar activity and PNA could be due to the ENSO impacts. In this study, solar cycle modulation of the ENSO effect on the PNA has been statistically examined by the observations from NOAA and NCEP/NCAR for the period of 1950-2014. Results indicate that during the high solar activity (HS) years, the PNA has stronger relevance to the ENSO, and the response of tropospheric geopotential height to ENSO variability is broadly similar to the typical positive PNA pattern. However, in the case of low solar activity (LS) years, the correlation between ENSO and PNA decreases relatively and the response has some resemblance to the negative phase of Arctic Oscillation (AO). Also, we find the impacts of solar activity on the middle troposphere are asymmetric during the different solar cycle phases, and the weak PNA-like response to solar activity only presents in the HS years. Closer inspection suggests that the higher solar activity has a much more remarkable modulation on the PNA-like response to the warm ENSO (WE) than that to the cold ENSO (CE), particularly over the Northeast Pacific region. The possible cause of the different responses might be the solar influence on the subtropical westerlies of upper troposphere. When the sea surface temperature (SST) of east-central tropical Pacific is anomalously warm, the upper tropospheric westerlies are significantly modulated by the higher solar activity, resulting in the acceleration and eastward shift of the North Pacific subtropical jet, which favors the propagation of WE signal from the tropical Pacific to the North Pacific, and consequently leading to the development of positive PNA-like pattern during the WE phase. Thus, it seems that the solar cycle can significantly modulate the WE effect on the PNA under the HS background.

Effect of boreal spring precipitation anomaly pattern change in the late 1990s over tropical Pacific on the atmospheric teleconnection

NASA Astrophysics Data System (ADS)

Guo, Yuanyuan; Wen, Zhiping; Chen, Ruidan; Li, Xiuzhen; Yang, Xiu-Qun

2018-02-01

Observational evidence showed that the leading mode of precipitation variability over the tropical Pacific during boreal spring experienced a pronounced interdecadal change around the late 1990s, characterized by a precipitation pattern shift from an eastern Pacific (EP) type to a central Pacific (CP) type. The distinct impacts of such a precipitation pattern shift on the extratropical atmospheric teleconnection were examined. An apparent poleward teleconnection extending from the tropics to the North Atlantic region was observed after 1998, while, there was no significant teleconnection before 1998. To understand why only the CP-type precipitation mode is associated with a striking atmospheric teleconnection after 1998, diagnostic analyses with the Eliassen-Palm flux and Rossby wave source (RWS) based on the barotropic vorticity equation were performed. The results show that for the EP-type precipitation mode, no significant RWS anomalies appeared over the subtropical Pacific due to the opposite effect of the vortex stretching and absolute vorticity advection processes. For the CP-type precipitation mode, however, there are both significant vorticity forcing source over the subtropical CP and clear poleward-propagation of Rossby wave. The spatial distribution of the CP-type precipitation pattern tends to excite a conspicuous anomalous southerly and a well-organized negative vorticity center over the subtropical CP where both the mean absolute vorticity gradient and mean divergence flow are large, hence, the interaction between the heating-induced anomalous circulation and the basic state made the generation of Rossby waves conceivable and effective. Such corresponding teleconnection responses to the prescribed heating were also examined by using a Linear Baroclinic Model (LBM). It turned out that significant poleward teleconnection pattern is only caused by the CP-type precipitation mode, rather than by the EP-type precipitation mode. Further sensitive experiments demonstrated that the change in spring basic state before and after 1998 played a relatively minor role in exciting such a teleconnection pattern, when compared with the tropical precipitation anomaly pattern change.

Teleconnected ocean forcing of Western North American droughts and pluvials during the last millennium

USGS Publications Warehouse

Routson, Cody C.; Woodhouse, Connie A.; Overpeck, Jonathan T.; Betancourt, Julio L.; McKay, Nicholas P.

2016-01-01

Western North America (WNA) is rich in hydroclimate reconstructions, yet questions remain about the causes of decadal-to-multidecadal hydroclimate variability. Teleconnection patterns preserved in annually-resolved tree-ring reconstructed drought maps, and anomalies in a global network of proxy sea surface temperature (SST) reconstructions, were used to reassess the evidence linking ocean forcing to WNA hydroclimate variability over the past millennium. Potential forcing mechanisms of the Medieval Climate Anomaly (MCA) and individual drought and pluvial events—including two multidecadal-length MCA pluvials—were evaluated. We show strong teleconnection patterns occurred during the driest (wettest) years within persistent droughts (pluvials), implicating SSTs as a potent hydroclimate forcing mechanism. The role of the SSTs on longer timescales is more complex. Pacific teleconnection patterns show little long-term change, whereas low-resolution SST reconstructions vary over decades to centuries. While weaker than the tropical Pacific teleconnections, North Atlantic teleconnection patterns and SST reconstructions also show links to WNA droughts and pluvials, and may in part account for longer-term WNA hydroclimate changes. Nonetheless, evidence linking WNA hydroclimate to SSTs still remains sparse and nuanced—especially over long-timescales with a broader range of hydroclimatic variability than characterized during the 20th century.

Evidence for Pacific Climate Regime Shifts as Preserved in a Southeast Alaska Ice Core

NASA Astrophysics Data System (ADS)

Porter, S. E.; Mosley-Thompson, E. S.; Thompson, L. G.

2012-12-01

Climate modes emanating from the Pacific sector have far-reaching effects across the globe. The El Niño/Southern Oscillation (ENSO) reflects anomalies in the sea surface temperature and pressure fields over the tropical Pacific, but climate implications from these anomalies extend to monsoon regions of Asia to North America and even Europe. The Pacific Decadal Oscillation (PDO) explains sea surface temperature anomalies in the North Pacific sector and influences the long-term behavior of the ENSO cycle as well as the storm track over North America expressed as the Pacific/North American Pattern (PNA). The impacts of both climate change and drastically reduced Arctic sea ice cover on these teleconnection patterns are poorly understood, and with little knowledge about their past behavior, predicting the changes in these climate modes is extremely difficult. An ice core from the col between Mt. Bona and Mt. Churchill in southeast Alaska provides an opportunity to examine the PDO prior to both the start of instrumental records and the more recent effects of anthropogenic climate change. The Bona-Churchill records of isotopic, dust, and chemical composition are compared to nearby meteorological station and 20th century reanalysis data to evaluate their strength as climate recorders. Climate indices such as the PDO and PNA, along with indices created to describe the strength and position of the Aleutian Low and Siberian High, are incorporated into the analysis to determine if proxy relationships are altered under different climate regimes. Satellite records of sea ice extent within the Sea of Okhotsk and the Bering Sea, when compared to the Bona-Churchill data, show a distinct change in behavior in the mid-1990s possibly in response to the temporary negative shift in the PDO. This behavioral shift is explored and placed into a broader climate context to determine whether similar events have occurred in the past or if this shift is unique to a rapidly warming Arctic.

Climate indices strongly influence old-growth forest carbon exchange

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wharton, Sonia; Falk, Matthias

We present a decade and a half (1998–2013) of carbon dioxide fluxes from an old-growth stand in the American Pacific Northwest to identify ecosystem-level responses to Pacific teleconnection patterns, including the El Niño/Southern Oscillation (ENSO). This study provides the longest, continuous record of old-growth eddy flux data to date from one of the longest running Fluxnet stations in the world. From 1998 to 2013, average annual net ecosystem exchange (F NEE) at Wind River AmeriFlux was –32 ± 84 g C m –2 yr –1 indicating that the late seral forest is on average a small net sink of atmosphericmore » carbon. However, interannual variability is high (>300 g C m –2 yr –1) and shows that the stand switches from net carbon sink to source in response to climate drivers associated with ENSO. The old-growth forest is a much stronger sink during La Niña years (mean F NEE = –90 g C m –2 yr –1) than during El Niño when the stand turns carbon neutral or into a small net carbon source (mean F NEE = +17 g C m –2 yr –1). Forest inventory data dating back to the 1930s show a similar correlation with the lower frequency Pacific North American (PNA) and Pacific Decadal Oscillation (PDO) whereby higher aboveground net primary productivity (F ANPP) is associated with cool phases of both the PNA and PDO. Furthermore, these measurements add evidence that carbon exchange in old-growth stands may be more sensitive to climate variability across shorter time scales than once thought.« less

Climate indices strongly influence old-growth forest carbon exchange

DOE PAGES

Wharton, Sonia; Falk, Matthias

2016-04-13

We present a decade and a half (1998–2013) of carbon dioxide fluxes from an old-growth stand in the American Pacific Northwest to identify ecosystem-level responses to Pacific teleconnection patterns, including the El Niño/Southern Oscillation (ENSO). This study provides the longest, continuous record of old-growth eddy flux data to date from one of the longest running Fluxnet stations in the world. From 1998 to 2013, average annual net ecosystem exchange (F NEE) at Wind River AmeriFlux was –32 ± 84 g C m –2 yr –1 indicating that the late seral forest is on average a small net sink of atmosphericmore » carbon. However, interannual variability is high (>300 g C m –2 yr –1) and shows that the stand switches from net carbon sink to source in response to climate drivers associated with ENSO. The old-growth forest is a much stronger sink during La Niña years (mean F NEE = –90 g C m –2 yr –1) than during El Niño when the stand turns carbon neutral or into a small net carbon source (mean F NEE = +17 g C m –2 yr –1). Forest inventory data dating back to the 1930s show a similar correlation with the lower frequency Pacific North American (PNA) and Pacific Decadal Oscillation (PDO) whereby higher aboveground net primary productivity (F ANPP) is associated with cool phases of both the PNA and PDO. Furthermore, these measurements add evidence that carbon exchange in old-growth stands may be more sensitive to climate variability across shorter time scales than once thought.« less

Analysing the teleconnection systems affecting the climate of the Carpathian Basin

NASA Astrophysics Data System (ADS)

Kristóf, Erzsébet; Bartholy, Judit; Pongrácz, Rita

2017-04-01

Nowadays, the increase of the global average near-surface air temperature is unequivocal. Atmospheric low-frequency variabilities have substantial impacts on climate variables such as air temperature and precipitation. Therefore, assessing their effects is essential to improve global and regional climate model simulations for the 21st century. The North Atlantic Oscillation (NAO) is one of the best-known atmospheric teleconnection patterns affecting the Carpathian Basin in Central Europe. Besides NAO, we aim to analyse other interannual-to-decadal teleconnection patterns, which might have significant impacts on the Carpathian Basin, namely, the East Atlantic/West Russia pattern, the Scandinavian pattern, the Mediterranean Oscillation, and the North-Sea Caspian Pattern. For this purpose primarily the European Centre for Medium-Range Weather Forecasts' (ECMWF) ERA-20C atmospheric reanalysis dataset and multivariate statistical methods are used. The indices of each teleconnection pattern and their correlations with temperature and precipitation will be calculated for the period of 1961-1990. On the basis of these data first the long range (i. e. seasonal and/or annual scale) forecast ability is evaluated. Then, we aim to calculate the same indices of the relevant teleconnection patterns for the historical and future simulations of Coupled Model Intercomparison Project Phase 5 (CMIP5) models and compare them against each other using statistical methods. Our ultimate goal is to examine all available CMIP5 models and evaluate their abilities to reproduce the selected teleconnection systems. Thus, climate predictions for the 21st century for the Carpathian Basin may be improved using the best-performing models among all CMIP5 model simulations.

Climate variability from the Florida Bay sedimentary record: Possible teleconnections to ENSO, PNA and CNP

USGS Publications Warehouse

Cronin, T. M.; Dwyer, Gary S.; Schwede, S.B.; Vann, C.D.; Dowsett, H.

2002-01-01

We analyzed decadal and interannual climate variability in South Florida since 1880 using geochemical and faunal paleosalinity indicators from isotopically dated sediment cores at Russell Bank in Florida Bay (FB). Using the relative abundance of 2 ostracode species and the Mg/Ca ratios in Loxoconcha matagordensis shells to reconstruct paleosalinity, we found evidence for cyclic oscillations in the salinity of central FB. During this time salinity fluctuated from as low as ~18 parts per thousand (ppt) to as high as ~57 ppt. Time series analyses suggest, in addition to a 5.6 yr Mg/Ca based salinity periodicity, there are 3 other modes of variability in paleosalinity indicators: 6-7, 8-9, and 13-14 yr periods which occur in all paleo-proxies. To search for factors that might cause salinity to vary in FB, we compared the Russell Bank paleosalinity record to South Florida winter rainfall, the Southern Oscillation Index (SOI), winter North Atlantic Oscillation (NAO), and the winter Pacific North American (PNA) index, and a surrogate for the PNA in the winter season, the Central North Pacific (CNP) index. SOI and PNA/CNP appear to be associated with South Florida winter precipitation. Time series analyses of SOI and winter rainfall for the period 1910-1999 suggest ~5, 6-7, 8-9 and 13-14 yr cycles. The 6-7 yr and 13-14 yr cycles correspond to those observed in the faunal and geochemical time series from Russell Bank. The main periods of the CNP index are 5-6 and 13-15 yr, which are similar to those observed in FB paleosalinity. Cross-spectral analyses show that winter rainfall and salinity are coherent at 5.6 yr with a salinity lag of ~1.6 mo. These results suggest that regional rainfall variability influences FB salinity over interannual and decadal timescales and that much of this variability may have its origin in climate variability in the Pacific Ocean/atmosphere system.

Combined effect of the East Atlantic/West Russia and Western Pacific teleconnections on the East Asian winter monsoon

NASA Astrophysics Data System (ADS)

Oh, Hyoeun; Jhun, Jong-Ghap; Ha, Kyung-Ja; Seo, Kyong-Hwan

2017-05-01

This study investigates the individual effects of the East Atlantic/West Russia (EATL/WRUS) and Western Pacific (WP) teleconnection patterns and their combined effect on the East Asian winter monsoon (EAWM). The contributions of the respective EATL/WRUS and WP teleconnection patterns to the EAWM are revealed by removing the dependence on the Arctic Oscillation (AO) and the El Niño-Southern Oscillation (ENSO) using a linear regression, which are named as N_EATL/WRUS and N_WP, respectively. This is because the EATL/WRUS (WP) is closely linked to the Arctic (tropics) region. A significant increase (decrease) in temperature over East Asia (EA) corresponding to a weak (strong) EAWM is associated with the N_EATL/WRUS and N_WP teleconnection patterns during the positive (negative) phases. In order to examine impacts of these two teleconnections on the EAWM, three types of effects are reconstructed on the basis of ± 0.5 standard deviation: 1) Combined effect, 2) N_EATL/WRUS effect, and 3) N_WP effect. The positive N_EATL/WRUS teleconnection induces to a weakened Siberian High and a shallow EA trough at the mid-troposphere through wave propagation, leading to the weak EAWM. During the positive N_WP pattern, warm air from the tropics flows toward the EA along western flank of an anomalous anticyclone over the North Pacific that is relevant to the meridional shift of the Aleutian Low. When the two mid-latitude teleconnections have the in-phase combination, the increase in temperature over EA appears to be more pronounced than the individual effects by transporting warm air from tropics via strong southeasterly wind anomalies induced by anomalous zonal pressure gradient between the Siberian High and Aleutian Low. Therefore, the impact of the mid-latitude teleconnections on the EAWM becomes robust and linearly superimposed, unlike a nonlinear in-phase combined effect of the AO and ENSO.

Interannual Variability in the Position and Strength of the East Asian Jet Stream and Its Relation to Large - scale Circulation

NASA Astrophysics Data System (ADS)

Chan, Duo; Zhang, Yang; Wu, Qigang

2013-04-01

East Asian Jet Stream (EASJ) is charactered by obvious interannual variability in strength and position (latitude), with wide impacts on East Asian climate in all seasons. In this study, two indices are established to measure the interannual variability in intensity and position of EAJS. Possible causing factors, including both local signals and non-local large-scale circulation, are examined using NCAP-NCAR reanalysis data to investigate their relations with jet variation. Our analysis shows that the relationship between the interannual variations of EASJ and these factors depends on seasons. In the summer, both the intensity and position of EASJ are closely related to the meridional gradient of local surface temperature, but display no apparent relationship with the larg-scale circulation. In cold seasons (autumn, winter and spring), both the local factor and the large-scale circulation, i.e. the Pacific/North American teleconnection pattern (PNA), play important roles in the interannual variability of the jet intensity. The variability in the jet position, however, is more correlated to the Arctic Oscillation (AO), especially in winter. Diagnostic analysis indicates that transient eddy activity plays an important role in connecting the interannual variability of EASJ position with AO.

Coherence among the Northern Hemisphere land, cryosphere, and ocean responses to natural variability and anthropogenic forcing during the satellite era

NASA Astrophysics Data System (ADS)

Gonsamo, Alemu; Chen, Jing M.; Shindell, Drew T.; Asner, Gregory P.

2016-08-01

A lack of long-term measurements across Earth's biological and physical systems has made observation-based detection and attribution of climate change impacts to anthropogenic forcing and natural variability difficult. Here we explore coherence among land, cryosphere and ocean responses to recent climate change using 3 decades (1980-2012) of observational satellite and field data throughout the Northern Hemisphere. Our results show coherent interannual variability among snow cover, spring phenology, solar radiation, Scandinavian Pattern, and North Atlantic Oscillation. The interannual variability of the atmospheric peak-to-trough CO2 amplitude is mostly impacted by temperature-mediated effects of El Niño/Southern Oscillation (ENSO) and Pacific/North American Pattern (PNA), whereas CO2 concentration is affected by Polar Pattern control on sea ice extent dynamics. This is assuming the trend in anthropogenic CO2 emission remains constant, or the interannual changes in the trends are negligible. Our analysis suggests that sea ice decline-related CO2 release may outweigh increased CO2 uptake through longer growing seasons and higher temperatures. The direct effects of variation in solar radiation and leading teleconnections, at least in part via their impacts on temperature, dominate the interannual variability of land, cryosphere and ocean indicators. Our results reveal a coherent long-term changes in multiple physical and biological systems that are consistent with anthropogenic forcing of Earth's climate and inconsistent with natural drivers.

Streamflow prediction using multi-site rainfall obtained from hydroclimatic teleconnection

NASA Astrophysics Data System (ADS)

Kashid, S. S.; Ghosh, Subimal; Maity, Rajib

2010-12-01

SummarySimultaneous variations in weather and climate over widely separated regions are commonly known as "hydroclimatic teleconnections". Rainfall and runoff patterns, over continents, are found to be significantly teleconnected, with large-scale circulation patterns, through such hydroclimatic teleconnections. Though such teleconnections exist in nature, it is very difficult to model them, due to their inherent complexity. Statistical techniques and Artificial Intelligence (AI) tools gain popularity in modeling hydroclimatic teleconnection, based on their ability, in capturing the complicated relationship between the predictors (e.g. sea surface temperatures) and predictand (e.g., rainfall). Genetic Programming is such an AI tool, which is capable of capturing nonlinear relationship, between predictor and predictand, due to its flexible functional structure. In the present study, gridded multi-site weekly rainfall is predicted from El Niño Southern Oscillation (ENSO) indices, Equatorial Indian Ocean Oscillation (EQUINOO) indices, Outgoing Longwave Radiation (OLR) and lag rainfall at grid points, over the catchment, using Genetic Programming. The predicted rainfall is further used in a Genetic Programming model to predict streamflows. The model is applied for weekly forecasting of streamflow in Mahanadi River, India, and satisfactory performance is observed.

Links of the significant wave height distribution in the Mediterranean sea with the Northern Hemisphere teleconnection patterns

NASA Astrophysics Data System (ADS)

Lionello, P.; Galati, M. B.

2008-06-01

This study analyzes the link between the SWH (Significant Wave Height) distribution in the Mediterranean Sea during the second half of the 20th century and the Northern Hemisphere SLP (Sea Level Pressure) teleconnection patterns. The SWH distribution is computed using the WAM (WAve Model) forced by the surface wind fields provided by the ERA-40 reanalysis for the period 1958-2001. The time series of mid-latitude teleconnection patterns are downloaded from the NOAA web site. This study shows that several mid-latitude patterns are linked to the SWH field in the Mediterranean, especially in its western part during the cold season: East Atlantic Pattern (EA), Scandinavian Pattern (SCA), North Atlantic Oscillation (NAO), East Atlantic/West Russia Pattern (EA/WR) and East Pacific/ North Pacific Pattern (EP/NP). Though the East Atlantic pattern exerts the largest influence, it is not sufficient to characterize the dominant variability. NAO, though relevant, has an effect smaller than EA and comparable to other patterns. Some link results from possibly spurious structures. Patterns which have a very different global structure are associated to similar spatial features of the wave variability in the Mediterranean Sea. These two problems are, admittedly, shortcomings of this analysis, which shows the complexity of the response of the Mediterranean SWH to global scale SLP teleconnection patterns.

Jacalin and peanut agglutinin (PNA) bindings in the taste bud cells of the rat: new reliable markers for type IV cells of the rat taste buds.

PubMed

Taniguchi, Ryo; Shi, Lei; Fujii, Masae; Ueda, Katsura; Honma, Shiho; Wakisaka, Satoshi

2005-12-01

Lectin histochemistry of Jacalin (Artocarpus integrifolia) and peanut agglutinin (PNA), specific lectins for galactosyl (beta-1, 3) N-acetylgalactosamine (galactosyl (beta-1, 3) GalNAc), was applied to the gustatory epithelium of the adult rat. In the ordinary lingual epithelium, Jacalin and PNA labeled the cell membrane from the basal to granular cell layer. They also bound membranes of rounded-cells at the basal portion of taste buds, but the number of PNA labeled cells was smaller than that of Jacalin labeled cells. There was no apparent difference in the binding patterns of Jacalin and PNA among the taste buds of the lingual papillae and those of the palatal epithelium. Occasionally, a few spindle-shaped cells were labeled with Jacalin, but not with PNA. Double labeling of Jacalin and alpha-gustducin, a specific marker for type II cells, revealed that Jacalin-labeled spindle-shaped taste cells were immunonegative for alpha-gustducin. Spindle-shaped cells expressing protein gene product 9.5 (PGP 9.5) immunoreactivity lacked Jacalin labeling. During the development of taste buds in circumvallate papillae, the binding pattern of Jacalin became almost identical from postnatal day 5. The present results indicate that rounded cells at the basal portion of the taste buds cells (type IV cells) bind to Jacalin and PNA, and these lectins are specific markers for type IV cells of the rat taste cells.

Trade wind inversion variability, dynamics and future change in Hawai'i

NASA Astrophysics Data System (ADS)

Cao, Guangxia

Using 1979-2003 radiosonde data at Hilo and Lihu'e, Hawai'i, the trade-wind inversion (TWI) is found to occur approximately 82% of the time at each station, with average base heights of 2225 +/- 14.3 m (781.9 +/- 1.4 hPa) for Hilo and 2076 +/- 12.5 m (798.8 +/- 1.2 hPa) for Lihu'e. A Weather Research and Forecast (WRF) meso-scale meteorological simulation suggests that island topography and heating contribute to the lifting of the TWI base at Hilo. Inversion base height has a September maximum and a secondary maximum in April. Frequency of inversion occurrence is significantly higher during winters and lower during summers of El Nino years. During the period of 1979-2003, the inversion frequency of occurrence is on upward trend at Hilo for spring (MAM), summer (JJA), and fall (SON) seasons and at Lihu'e for all seasons and for annual values. Composite analysis shows that patterns of geopotential height (GPH), air temperature, u- and v-wind, omega wind, relative and specific humidity, upward longwave radiation flux, net longwave radiation flux, precipitable water, convective precipitation rate, and total cloud cover significantly respond to the TWI base height. For example, the GPH pattern contains a distinctive Pacific North America Teleconnection (PNA) signature, and the magnitudes of PNA centers over 45°N, 165°W for the difference between none and inversion is over 40 m at 200 hPa and 25 m at 850 hPa. The monthly composites show that months with lower (higher) inversion base height and higher (lower) inversion occurrence frequency are linked with the following characteristics: lower (higher) GPH anomalies centered at 30°N, 160°W, lower (higher) temperature anomalies within 300--700 hPa, stronger (weaker) easterly at low levels and northerly anomaly over Hawai'i, and small upward (downward) vertical wind or rising (sinking) motion north of Hawai'i. Using the above characteristics to study the Community Climate System Model (CCSM) composites leads to the prediction that the TWI under increased CO2 forcing atmosphere will be lower in base height and more frequently.

ENSO Atmospheric Teleconnections and Their Response to Greenhouse Gas Forcing

NASA Astrophysics Data System (ADS)

Yeh, Sang-Wook; Cai, Wenju; Min, Seung-Ki; McPhaden, Michael J.; Dommenget, Dietmar; Dewitte, Boris; Collins, Matthew; Ashok, Karumuri; An, Soon-Il; Yim, Bo-Young; Kug, Jong-Seong

2018-03-01

El Niño and Southern Oscillation (ENSO) is the most prominent year-to-year climate fluctuation on Earth, alternating between anomalously warm (El Niño) and cold (La Niña) sea surface temperature (SST) conditions in the tropical Pacific. ENSO exerts its impacts on remote regions of the globe through atmospheric teleconnections, affecting extreme weather events worldwide. However, these teleconnections are inherently nonlinear and sensitive to ENSO SST anomaly patterns and amplitudes. In addition, teleconnections are modulated by variability in the oceanic and atmopsheric mean state outside the tropics and by land and sea ice extent. The character of ENSO as well as the ocean mean state have changed since the 1990s, which might be due to either natural variability or anthropogenic forcing, or their combined influences. This has resulted in changes in ENSO atmospheric teleconnections in terms of precipitation and temperature in various parts of the globe. In addition, changes in ENSO teleconnection patterns have affected their predictability and the statistics of extreme events. However, the short observational record does not allow us to clearly distinguish which changes are robust and which are not. Climate models suggest that ENSO teleconnections will change because the mean atmospheric circulation will change due to anthropogenic forcing in the 21st century, which is independent of whether ENSO properties change or not. However, future ENSO teleconnection changes do not currently show strong intermodel agreement from region to region, highlighting the importance of identifying factors that affect uncertainty in future model projections.

Role of Tropical Atlantic SST Variability as a Modulator of El Nino Teleconnections

NASA Technical Reports Server (NTRS)

Ham, Yoo-Geun; Sung, Mi-Kyung; An, Soon-II; Schubert, Siegfried D.; Kug, Jong-Seong

2014-01-01

The present study suggests that the off-equatorial North Atlantic (NATL) SST warming plays a significant role in modulating El Niño teleconnection and its impact on the North Atlantic and European regions. The El Niño events accompanied by NATL SST warming exhibit south-north dipole pattern over the Western Europe to Atlantic, while the ENSO teleconnection pattern without NATL warming exhibits a Rossby wave-like pattern confined over the North Pacific and western Atlantic. Especially, the El Niño events with NATL warming show positive (negative) geopotential-height anomalies over the North Atlantic (Western Europe) which resemble the negative phase of the NAO. Consistently, it is shown using a simple statistical model that NATL SSTA in addition to the tropical Pacific SSTA leads to better prediction on regional climate variation over the North Atlantic and European regions. This role of NATL SST on ENSO teleconnection is also validated and discussed in a long term simulation of coupled global circulation model (CGCM).

Multiscale low-frequency circulation modes in the global atmosphere

NASA Technical Reports Server (NTRS)

Lau, K.-M.; Sheu, P.-J.; Kang, I.-S.

1994-01-01

In this paper, fundamental multiscale circulation modes in the global atmosphere are identified with the objective of providing better understanding of atmospheric low-frequency variabilities over a wide range of spatial and temporal scales. With the use of a combination of rotated principal component technique, singular spectrum analysis, and phase space portraits, three categories of basic multiscale modes in the atmosphere are found. The first is the interannual-mode (IAM), which is dominated by time scales longer than a year and can be attributed to heating and circulation anomalies associated with the coupled tropical ocean-atmosphere, in particular the El Nino-Southern Oscillation. The second is a set of tropical intraseasonal modes consisting of three separate multiscale patterns (ISO-1, -2, -3) related to tropical heating that can be identified with the different phases of the Madden-Julian Oscillation (MJO), including its teleconnection to the extratropics. The ISO spatial and temporal patterns suggest that the extratropical wave train in the North Pacific and North America is related to heating over the Maritime Continent and that the evolution of the MJO around the equator may require forcing from the extratropics spawning convection over the Indian Ocean. The third category represents extratropical intraseasonal oscillations arising from internal dynamics of the basic-state circulation. In the Northern Hemisphere, there are two distinct circulation modes with multiple frequencies in this category: the Pacific/North America (PNA) and the North Atlantic/Eurasia (NAE). In the Southern Hemisphere, two phase-locked modes (PSA-1 and PSA-2) are found depicting an eastward propagating wave train from eastern Australia, via the Pacific South America to the South Atlantic. The extratropical modes exhibit temporal characteristics such as phase locking and harmonic oscillations possibly associated with quadratically nonlinear dynamical systems. Additionally, the observed monthly and seasonal anomalies arise from a complex interplay of the various multiscale low-frequency modes. The relative dominance of the different modes varies widely from month to month and from year to year. On the monthly time scale, while one or two mechanisms may dominate in one year, no single mechanism seems to dominate for all years. There are indications that when the IAM, that is, ENSO heating patterns are strong, the extratropical modes may be suppressed and vice versa. For the seasonal mean, the interannual mode tends to dominate and the contribution from the PNA remains quite significant.

Global linkages between teleconnection patterns and the terrestrial biosphere

NASA Astrophysics Data System (ADS)

Dahlin, Kyla M.; Ault, Toby R.

2018-07-01

Interannual variability in the global carbon cycle is largely due to variations in carbon uptake by terrestrial ecosystems, yet linkages between climate variability and variability in the terrestrial carbon cycle are not well understood at the global scale. Using a 30-year satellite record of semi-monthly leaf area index (LAI), we show that four modes of climate variability - El Niño/Southern Oscillation, the North Atlantic Oscillation, the Atlantic Meridional Mode, and the Indian Ocean Dipole Mode - strongly impact interannual vegetation growth patterns, with 68% of the land surface impacted by at least one of these teleconnection patterns, yet the spatial distribution of these impacts is heterogeneous. Considering the patterns' impacts by biome, none has an exclusively positive or negative relationship with LAI. Our findings imply that future changes in the frequency and/or magnitude of teleconnection patterns will lead to diverse changes to the terrestrial biosphere and the global carbon cycle.

The Asian-Bering-North American teleconnection: seasonality, maintenance, and climate impact on North America

NASA Astrophysics Data System (ADS)

Yu, Bin; Lin, H.; Wu, Z. W.; Merryfield, W. J.

2018-03-01

The Asian-Bering-North American (ABNA) teleconnection index is constructed from the normalized 500-hPa geopotential field by excluding the Pacific-North American pattern contribution. The ABNA pattern features a zonally elongated wavetrain originating from North Asia and flowing downstream across Bering Sea and Strait towards North America. The large-scale teleconnection is a year-round phenomenon that displays strong seasonality with the peak variability in winter. North American surface temperature and temperature extremes, including warm days and nights as well as cold days and nights, are significantly controlled by this teleconnection. The ABNA pattern has an equivalent barotropic structure in the troposphere and is supported by synoptic-scale eddy forcing in the upper troposphere. Its associated sea surface temperature anomalies exhibit a horseshoe-shaped structure in the North Pacific, most prominent in winter, which is driven by atmospheric circulation anomalies. The snow cover anomalies over the West Siberian plain and Central Siberian Plateau in autumn and spring and over southern Siberia in winter may act as a forcing influence on the ABNA pattern. The snow forcing influence in winter and spring can be traced back to the preceding season, which provides a predictability source for this teleconnection and for North American temperature variability. The ABNA associated energy budget is dominated by surface longwave radiation anomalies year-round, with the temperature anomalies supported by anomalous downward longwave radiation and damped by upward longwave radiation at the surface.

Variability of Extreme Precipitation Events in Tijuana, Mexico During ENSO Years

NASA Astrophysics Data System (ADS)

Cavazos, T.; Rivas, D.

2007-05-01

We present the variability of daily precipitation extremes (top 10 percecnt) in Tijuana, Mexico during 1950-2000. Interannual rainfall variability is significantly modulated by El Nino/Southern Oscillation. The interannual precipitation variability exhibits a large change with a relatively wet period and more variability during 1976- 2000. The wettest years and the largest frequency of daily extremes occurred after 1976-1977, with 6 out of 8 wet years characterized by El Nino episodes and 2 by neutral conditions. However, more than half of the daily extremes during 1950-2000 occurred in non-ENSO years, evidencing that neutral conditions also contribute significantly to extreme climatic variability in the region. Extreme events that occur in neutral (strong El Nino) conditions are associated with a pineapple express and a neutral PNA (negative TNH) teleconnection pattern that links an anomalous tropical convective forcing west (east) of the date line with a strong subtropical jet over the study area. At regional scale, both types of extremes are characterized by a trough in the subtropical jet over California/Baja California, which is further intensified by thermal interaction with an anomalous warm California Current off Baja California, low-level moisture advection from the subtropical warm sea-surface region, intense convective activity over the study area and extreme rainfall from southern California to Baja California.

Analysis of precipitation teleconnections in CMIP models as a measure of model fidelity in simulating precipitation

NASA Astrophysics Data System (ADS)

Langenbrunner, B.; Neelin, J.; Meyerson, J.

2011-12-01

The accurate representation of precipitation is a recurring issue in global climate models, especially in the tropics. Poor skill in modeling the variability and climate teleconnections associated with El Niño/Southern Oscillation (ENSO) also persisted in the latest Climate Model Intercomparison Project (CMIP) campaigns. Observed ENSO precipitation teleconnections provide a standard by which we can judge a given model's ability to reproduce precipitation and dynamic feedback processes originating in the tropical Pacific. Using CMIP3 Atmospheric Model Intercomparison Project (AMIP) runs as a baseline, we compare precipitation teleconnections between models and observations, and we evaluate these results against available CMIP5 historical and AMIP runs. Using AMIP simulations restricts evaluation to the atmospheric response, as sea surface temperatures (SSTs) in AMIP are prescribed by observations. We use a rank correlation between ENSO SST indices and precipitation to define teleconnections, since this method is robust to outliers and appropriate for non-Gaussian data. Spatial correlations of the modeled and observed teleconnections are then evaluated. We look at these correlations in regions of strong precipitation teleconnections, including equatorial S. America, the "horseshoe" region in the western tropical Pacific, and southern N. America. For each region and season, we create a "normalized projection" of a given model's teleconnection pattern onto that of the observations, a metric that assesses the quality of regional pattern simulations while rewarding signals of correct sign over the region. Comparing this to an area-averaged (i.e., more generous) metric suggests models do better when restrictions on exact spatial dependence are loosened and conservation constraints apply. Model fidelity in regional measures remains far from perfect, suggesting intrinsic issues with the models' regional sensitivities in moist processes.

Cold season Africa-Asia multidecadal teleconnection pattern and its relation to the Atlantic multidecadal variability

NASA Astrophysics Data System (ADS)

Sun, Cheng; Li, Jianping; Ding, Ruiqiang; Jin, Ze

2017-06-01

A prominent teleconnection pattern of multidecadal variability of cold season (November to April) upper-level atmospheric circulation over North Africa and Eurasia (NA-EA) is revealed by empirical orthogonal function analysis of the Twentieth Century Reanalysis data. This teleconnection pattern is characterized by an eastward propagating wave train with a zonal wavenumber of 5-6 between 20° and 40°N, extending from the northwest coast of Africa to East Asia, and thus is referred to as the Africa-Asia multidecadal teleconnection pattern (AAMT). One-point correlation maps show that the teleconnectivity of AAMT is strong and further demonstrate the existence of the AAMT. The AAMT shapes the spatial structure of multidecadal change in atmospheric circulation over the NA-EA region, and in particular the AAMT pattern and associated fields show similar structures to the change occurring around the early 1960s. A strong in-phase relationship is observed between the AAMT and Atlantic multidecadal variability (AMV) and this connection is mainly due to Rossby wave dynamics. Barotropic modeling results suggest that the upper-level Rossby wave source generated by the AMV can excite the AAMT wave train, and Rossby wave ray tracing analysis further highlights the role of the Asian jet stream in guiding the wave train to East Asia. The AAMT acts as an atmospheric bridge conveying the influence of AMV onto the downstream multidecadal climate variability. The AMV is closely related to the coordinated change in surface and tropospheric air temperatures over Northwest Africa, the Arabian Peninsula and Central China, which may result from the adiabatic expansion/compression of air associated with the AAMT.

Glycoconjugate distribution in early human notochord and axial mesenchyme.

PubMed

Götz, W; Quondamatteo, F

2001-02-01

Glycosylation patterns of cells and tissues give insights into spatially and temporally regulated developmental processes and can be detected histochemically using plant lectins with specific affinities for sugar moieties. The early development of the vertebral column in man is a process which has never been investigated by lectin histochemistry. Therefore, we studied binding of several lectins (AIA, Con A, GSA II, LFA, LTA, PNA, RCA I, SBA, SNA, WGA) in formaldehyde-fixed sections of the axial mesenchyme of 5 human embryos in Carnegie stages 12-15. During these developmental stages, an unsegmented mesenchyme covers the notochord. Staining patterns did not show striking temporal variations except for SBA which stained the cranial axial mesenchyme only in the early stage 12 embryo and for PNA, of which the staining intensity in the mesenchyme decreased with age. The notochord appeared as a highly glycosylated tissue. Carbohydrates detected may correspond to adhesion molecules or to secreted substances like proteoglycans or proteins which could play an inductive role, for example, for the neural tube. The axial perinotochordal unsegmented mesenchyme showed strong PNA binding. Therefore, its function as a PNA-positive "barrier" tissue is discussed. The endoderm of the primitive gut showed a lectin-binding pattern that was similar to that of the notochord, which may correlate with interactions between these tissues during earlier developmental stages.

PNA-PEG modified silicon platforms as functional bio-interfaces for applications in DNA microarrays and biosensors.

PubMed

Cattani-Scholz, Anna; Pedone, Daniel; Blobner, Florian; Abstreiter, Gerhard; Schwartz, Jeffrey; Tornow, Marc; Andruzzi, Luisa

2009-03-09

The synthesis and characterization of two types of silicon-based biofunctional interfaces are reported; each interface bonds a dense layer of poly(ethylene glycol) (PEG(n)) and peptide nucleic acid (PNA) probes. Phosphonate self-assembled monolayers were derivatized with PNA using a maleimido-terminated PEG(45). Similarly, siloxane monolayers were functionalized with PNA using a maleimido-terminated PEG(45) spacer and were subsequently modified with a shorter methoxy-terminated PEG(12) ("back-filling"). The long PEG(45) spacer was used to distance the PNA probe from the surface and to minimize undesirable nonspecific adsorption of DNA analyte. The short PEG(12) "back-filler" was used to provide additional passivation of the surface against nonspecific DNA adsorption. X-ray photoelectron spectroscopic (XPS) analysis near the C 1s and N 1s ionization edges was done to characterize chemical groups formed in the near-surface region, which confirmed binding of PEG and PNA to the phosphonate and silane films. XPS also indicated that additional PEG chains were tethered to the surface during the back-filling process. Fluorescence hybridization experiments were carried out with complementary and noncDNA strands; both phosphonate and siloxane biofunctional surfaces were effective for hybridization of cDNA strands and significantly reduced nonspecific adsorption of the analyte. Spatial patterns were prepared by polydimethylsiloxane (PDMS) micromolding on the PNA-functionalized surfaces; selective hybridization of fluorescently labeled DNA was shown at the PNA functionalized regions, and physisorption at the probe-less PEG-functionalized regions was dramatically reduced. These results show that PNA-PEG derivatized phosphonate monolayers hold promise for the smooth integration of device surface chemistry with semiconductor technology for the fabrication of DNA biosensors. In addition, our results confirm that PNA-PEG derivatized self-assembled carboxyalkylsiloxane films are promising substrates for DNA microarray applications.

Impacts of four northern-hemisphere teleconnection patterns on atmospheric circulations over Eurasia and the Pacific

NASA Astrophysics Data System (ADS)

Gao, Tao; Yu, Jin-yi; Paek, Houk

2017-08-01

The impacts of four teleconnection patterns on atmospheric circulation components over Eurasia and the Pacific region, from low to high latitudes in the Northern Hemisphere (NH), were investigated comprehensively in this study. The patterns, as identified by the Climate Prediction Center (USA), were the East Atlantic (EA), East Atlantic/Western Russia (EAWR), Polar/Eurasia (POLEUR), and Scandinavian (SCAND) teleconnections. Results indicate that the EA pattern is closely related to the intensity of the subtropical high over different sectors of the NH in all seasons, especially boreal winter. The wave train associated with this pattern serves as an atmospheric bridge that transfers Atlantic influence into the low-latitude region of the Pacific. In addition, the amplitudes of the EAWR, SCAND, and POLEUR patterns were found to have considerable control on the "Vangengeim-Girs" circulation that forms over the Atlantic-Eurasian region in winter or spring. The EA and EAWR mainly affect the westerlies in winter and spring and the POLEUR and SCAND, respectively, in summer and winter. Strong westerlies confine the extension of the North Polar vortex, which generally results in a small weak vortex and a shallow East Asian trough located in a position further east than normal. Furthermore, the North Polar vortex presents significant connections with the patterns during winter and summer. Analyses in this work suggest that the teleconnection patterns in summer could be driven, at least partly, by the Atlantic Multidecadal Oscillation, which to some degree might transmit the influence of the Atlantic Ocean to Eurasia and the Pacific region.

An Evaluation of Teleconnections Over the United States in an Ensemble of AMIP Simulations with the MERRA-2 Configuration of the GEOS Atmospheric Model

NASA Technical Reports Server (NTRS)

Collow, Allison B. Marquardt; Mahanama, Sarith P.; Bosilovich, Michael G.; Koster, Randal D.; Schubert, Siegfried D.

2017-01-01

The atmospheric general circulation model that is used in NASA's Modern Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) is evaluated with respect to the relationship between large-scale teleconnection patterns and daily temperature and precipitation over the United States (US) using a ten-member ensemble of simulations, referred to as M2AMIP. A focus is placed on four teleconnection patterns that are known to influence weather and climate in the US: El Nino Southern Oscillation, the Pacific Decadal Oscillation, the North Atlantic Oscillation, and the Pacific-North American Pattern. The monthly and seasonal indices associated with the patterns are correlated with daily temperature and precipitation statistics including: (i) monthly mean 2 m temperature and precipitation, (ii) the frequency of extreme temperature events at the 90th, 95th, and 99th percentiles, and (iii) the frequency and intensity of extreme precipitation events classified at the 90th, 95th, and 99th percentiles.Correlations obtained with M2AMIP data and thus the strength of teleconnections in the free-running model are evaluated through comparison against corresponding correlations computed from observations and from MERRA-2. Overall, the strongest teleconnections in all datasets occur during the winter and coincide with the largest agreement between the observations, MERRA-2, and M2AMIP. When M2AMIP does capture the correlation seen in observations, there is a tendency for the spatial extent to be exaggerated. The weakest agreement between the data sources, for all teleconnection patterns, is in the correlation with extreme precipitation; however there are discrepancies between the datasets in the number of days with at least 1 mm of precipitation: M2AMIP has too few days with precipitation in the Northwest and the Northern Great Plains and too many days in the Northeast. In JJA, M2AMIP has too few days with precipitation in the western two-thirds of the country and too many days with precipitation along the east coast.

Assessing the effect of the relative atmospheric angular momentum (AAM) on length-of-day (LOD) variations under climate warming

NASA Astrophysics Data System (ADS)

Lehmann, E.; Hansen, F.; Ulbrich, U.; Nevir, P.; Leckebusch, G. C.

2009-04-01

While most studies on model-projected future climate warming discuss climatological quantities, this study investigates the response of the relative atmospheric angular momentum (AAM) to climate warming for the 21th century and discusses its possible effects on future length-of-day variations. Following the derivation of the dynamic relation between atmosphere and solid earth by Barnes et al. (Proc. Roy. Soc., 1985) this study relates the axial atmospheric excitation function X3 to changes in length-of-day that are proportional to variations in zonal winds. On interannual time scales changes in the relative AAM (ERA40 reanalyses) are well correlated with observed length-of-day (LOD, IERS EOP CO4) variability (r=0.75). The El Niño-Southern Oscillation (ENSO) is a prominent coupled ocean-atmosphere phenomenon to cause global climate variability on interannual time scales. Correspondingly, changes in observed LOD relate to ENSO due to observed strong wind anomalies. This study investigates the varying effect of AAM anomalies on observed LOD by relating AAM to variations to ENSO teleconnections (sea surface temperatures, SSTs) and the Pacific North America (PNA) oscillation for the 20th and 21st century. The differently strong effect of strong El Niño events (explained variance 71%-98%) on present time (1962-2000) observed LOD-AAM relation can be associated to variations in location and strength of jet streams in the upper troposphere. Correspondingly, the relation between AAM and SSTs in the NIÑO 3.4 region also varies between explained variances of 15% to 73%. Recent coupled ocean-atmosphere projections on future climate warming suggest changes in frequency and amplitude of ENSO events. Since changes in the relative AAM indicate shifts in large-scale atmospheric circulation patterns due to climate change, AAM - ENSO relations are assessed in coupled atmosphere-ocean (ECHAM5-OM1) climate warming projections (A1B) for the 21st century. A strong rise (+31%) in relative AAM is observed with major contributions in the upper troposphere where increased jet streams cause large AAM anomalies. Due to increasing westerly winds, an eastward shift can be observed during strong El Niño events for the Pacific and North America centers of the PNA while its southeast center is less pronounced and shifts to the West. As a result, the PNA region during strong 21th century El Niño events is closely located to the PNA region of mean atmospheric conditions of present time. Further analyses on the climate warming scenario (A1B) determined a total of 28 strong El Niño events suggesting a steady increase in ENSO events, magnitude and duration during the last decades of the 21st century. Rising Niño 3.4 SSTs exceed global increases by 15%. Correspondingly to present times, the AAM-SST relation also indicates a range of explained variances from 8% to 82%. Ongoing analyses on 21st century climate warming relate zonal wind anomalies in the upper troposphere to SST patterns of individual strong El Niños to estimate a possible effect of the relative AAM on length-of-day variations.

Diversity in the representation of large-scale circulation associated with ENSO-Indian summer monsoon teleconnections in CMIP5 models

NASA Astrophysics Data System (ADS)

Ramu, Dandi A.; Chowdary, Jasti S.; Ramakrishna, S. S. V. S.; Kumar, O. S. R. U. B.

2018-04-01

Realistic simulation of large-scale circulation patterns associated with El Niño-Southern Oscillation (ENSO) is vital in coupled models in order to represent teleconnections to different regions of globe. The diversity in representing large-scale circulation patterns associated with ENSO-Indian summer monsoon (ISM) teleconnections in 23 Coupled Model Intercomparison Project Phase 5 (CMIP5) models is examined. CMIP5 models have been classified into three groups based on the correlation between Niño3.4 sea surface temperature (SST) index and ISM rainfall anomalies, models in group 1 (G1) overestimated El Niño-ISM teleconections and group 3 (G3) models underestimated it, whereas these teleconnections are better represented in group 2 (G2) models. Results show that in G1 models, El Niño-induced Tropical Indian Ocean (TIO) SST anomalies are not well represented. Anomalous low-level anticyclonic circulation anomalies over the southeastern TIO and western subtropical northwest Pacific (WSNP) cyclonic circulation are shifted too far west to 60° E and 120° E, respectively. This bias in circulation patterns implies dry wind advection from extratropics/midlatitudes to Indian subcontinent. In addition to this, large-scale upper level convergence together with lower level divergence over ISM region corresponding to El Niño are stronger in G1 models than in observations. Thus, unrealistic shift in low-level circulation centers corroborated by upper level circulation changes are responsible for overestimation of ENSO-ISM teleconnections in G1 models. Warm Pacific SST anomalies associated with El Niño are shifted too far west in many G3 models unlike in the observations. Further large-scale circulation anomalies over the Pacific and ISM region are misrepresented during El Niño years in G3 models. Too strong upper-level convergence away from Indian subcontinent and too weak WSNP cyclonic circulation are prominent in most of G3 models in which ENSO-ISM teleconnections are underestimated. On the other hand, many G2 models are able to represent most of large-scale circulation over Indo-Pacific region associated with El Niño and hence provide more realistic ENSO-ISM teleconnections. Therefore, this study advocates the importance of representation/simulation of large-scale circulation patterns during El Niño years in coupled models in order to capture El Niño-monsoon teleconnections well.

Characteristics of atmospheric circulation patterns associated with extreme temperatures over North America in observations and climate models

NASA Astrophysics Data System (ADS)

Loikith, Paul C.

Motivated by a desire to understand the physical mechanisms involved in future anthropogenic changes in extreme temperature events, the key atmospheric circulation patterns associated with extreme daily temperatures over North America in the current climate are identified. Several novel metrics are used to systematically identify and describe these patterns for the entire continent. The orientation, physical characteristics, and spatial scale of these circulation patterns vary based on latitude, season, and proximity to important geographic features (i.e., mountains, coastlines). The anomaly patterns associated with extreme cold events tend to be similar to, but opposite in sign of, those associated with extreme warm events, especially within the westerlies, and tend to scale with temperature in the same locations. The influence of the Pacific North American (PNA) pattern, the Northern Annular Mode (NAM), and the El Niño-Southern Oscillation (ENSO) on extreme temperature days and months shows that associations between extreme temperatures and the PNA and NAM are stronger than associations with ENSO. In general, the association with extremes tends to be stronger on monthly than daily time scales. Extreme temperatures are associated with the PNA and NAM in locations typically influenced by these circulation patterns; however many extremes still occur on days when the amplitude and polarity of these patterns do not favor their occurrence. In winter, synoptic-scale, transient weather disturbances are important drivers of extreme temperature days; however these smaller-scale events are often concurrent with amplified PNA or NAM patterns. Associations are weaker in summer when other physical mechanisms affecting the surface energy balance, such as anomalous soil moisture content, are associated with extreme temperatures. Analysis of historical runs from seventeen climate models from the CMIP5 database suggests that most models simulate realistic circulation patterns associated with extreme temperature days in most places. Model-simulated patterns tend to resemble observed patterns better in the winter than the summer and at 500 hPa than at the surface. There is substantial variability among the suite of models analyzed and most models simulate circulation patterns more realistically away from influential features such as large bodies of water and complex topography.

Principal network analysis: identification of subnetworks representing major dynamics using gene expression data

PubMed Central

Kim, Yongsoo; Kim, Taek-Kyun; Kim, Yungu; Yoo, Jiho; You, Sungyong; Lee, Inyoul; Carlson, George; Hood, Leroy; Choi, Seungjin; Hwang, Daehee

2011-01-01

Motivation: Systems biology attempts to describe complex systems behaviors in terms of dynamic operations of biological networks. However, there is lack of tools that can effectively decode complex network dynamics over multiple conditions. Results: We present principal network analysis (PNA) that can automatically capture major dynamic activation patterns over multiple conditions and then generate protein and metabolic subnetworks for the captured patterns. We first demonstrated the utility of this method by applying it to a synthetic dataset. The results showed that PNA correctly captured the subnetworks representing dynamics in the data. We further applied PNA to two time-course gene expression profiles collected from (i) MCF7 cells after treatments of HRG at multiple doses and (ii) brain samples of four strains of mice infected with two prion strains. The resulting subnetworks and their interactions revealed network dynamics associated with HRG dose-dependent regulation of cell proliferation and differentiation and early PrPSc accumulation during prion infection. Availability: The web-based software is available at: http://sbm.postech.ac.kr/pna. Contact: dhhwang@postech.ac.kr; seungjin@postech.ac.kr Supplementary information: Supplementary data are available at Bioinformatics online. PMID:21193522

Regional Famine Patterns of The Last Millennium as Influenced by Aggregated Climate Teleconnections

NASA Astrophysics Data System (ADS)

Santoro, Michael Melton

Famine is the result of a complex set of environmental and social factors. Climate conditions are established as environmental factors contributing to famine occurrence, often through teleconnective patterns. This dissertation is designed to investigate the combined influence on world famine patterns of teleconnections, specifically the North Atlantic Oscillation (NAO), Southern Oscillation (SO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), or regional climate variations such as the South Asian Summer Monsoon (SASM). The investigation is three regional case studies of famine patterns specifically, Egypt, the British Isles, and India. The first study (published in Holocene) employs the results of a Principal Component Analysis (PCA) yielding a SO-NAO eigenvector to predict major Egyptian famines between AD 1049-1921. The SO-NAO eigenvector (1) successfully discriminates between the 5-10 years preceding a famine and the other years, (2) predicts eight of ten major famines, and (3) correctly identifies fifty out of eighty events (63%) of food availability decline leading up to major famines. The second study investigates the impact of the NAO, PDO, SO, and AMO on 63 British Isle famines between AD 1049 and 1914 attributed to climate causes in historical texts. Stepwise Regression Analysis demonstrates that the 5-year lagged NAO is the primary teleconnective influence on famine patterns; it successfully discriminates 73.8% of weather-related famines in the British Isles from 1049 to 1914. The final study identifies the aggregated influence of the NAO, SO, PDO, and SASM on 70 Indian famines from AD 1049 to 1955. PCA results in a NAO-SOI vector and SASM vector that predicts famine conditions with a positive NAO and negative SO, distinct from the secondary SASM influence. The NAO-famine relationship is consistently the strongest; 181 of 220 (82%) of all famines occurred during positive NAO years. Ultimately, the causes of famine are complex and involve many factors including societal and climatic. This dissertation demonstrates that climate teleconnections impact famine patterns and often the aggregates of multiple climate variables hold the most significant climatic impact. These results will increase the understanding of famine patterns and will help to better allocate resources to alleviate future famines.

Long-term reliability of the Athabasca River (Alberta, Canada) as the water source for oil sands mining

PubMed Central

Sauchyn, David J.; St-Jacques, Jeannine-Marie; Luckman, Brian H.

2015-01-01

Exploitation of the Alberta oil sands, the world’s third-largest crude oil reserve, requires fresh water from the Athabasca River, an allocation of 4.4% of the mean annual flow. This allocation takes into account seasonal fluctuations but not long-term climatic variability and change. This paper examines the decadal-scale variability in river discharge in the Athabasca River Basin (ARB) with (i) a generalized least-squares (GLS) regression analysis of the trend and variability in gauged flow and (ii) a 900-y tree-ring reconstruction of the water-year flow of the Athabasca River at Athabasca, Alberta. The GLS analysis removes confounding transient trends related to the Pacific Decadal Oscillation (PDO) and Pacific North American mode (PNA). It shows long-term declining flows throughout the ARB. The tree-ring record reveals a larger range of flows and severity of hydrologic deficits than those captured by the instrumental records that are the basis for surface water allocation. It includes periods of sustained low flow of multiple decades in duration, suggesting the influence of the PDO and PNA teleconnections. These results together demonstrate that low-frequency variability must be considered in ARB water allocation, which has not been the case. We show that the current and projected surface water allocations from the Athabasca River for the exploitation of the Alberta oil sands are based on an untenable assumption of the representativeness of the short instrumental record. PMID:26392554

Prepubertal Development of Gonadotropin-Releasing Hormone Neuron Activity Is Altered by Sex, Age, and Prenatal Androgen Exposure.

PubMed

Dulka, Eden A; Moenter, Suzanne M

2017-11-01

Gonadotropin-releasing hormone (GnRH) neurons regulate reproduction though pulsatile hormone release. Disruption of GnRH release as measured via luteinizing hormone (LH) pulses occurs in polycystic ovary syndrome (PCOS), and in young hyperandrogenemic girls. In adult prenatally androgenized (PNA) mice, which exhibit many aspects of PCOS, increased LH is associated with increased GnRH neuron action potential firing. How GnRH neuron activity develops over the prepubertal period and whether this is altered by sex or prenatal androgen treatment are unknown. We hypothesized GnRH neurons are active before puberty and that this activity is sexually differentiated and altered by PNA. Dams were injected with dihydrotestosterone (DHT) on days 16 to 18 post copulation to generate PNA mice. Action potential firing of GFP-identified GnRH neurons in brain slices from 1-, 2-, 3-, and 4-week-old and adult mice was monitored. GnRH neurons were active at all ages tested. In control females, activity increased with age through 3 weeks, then decreased to adult levels. In contrast, activity did not change in PNA females and was reduced at 3 weeks. Activity was higher in control females than males from 2 to 3 weeks. PNA did not affect GnRH neuron firing rate in males at any age. Short-term action potential patterns were also affected by age and PNA treatment. GnRH neurons are thus typically more active during the prepubertal period than adulthood, and PNA reduces prepubertal activity in females. Prepubertal activity may play a role in establishing sexually differentiated neuronal networks upstream of GnRH neurons; androgen-induced changes during this time may contribute to the adult PNA, and possibly PCOS, phenotype. Copyright © 2017 Endocrine Society.

Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection

PubMed Central

Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

2016-01-01

Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection. PMID:26838053

Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection.

PubMed

Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

2016-02-03

Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection.

Atmospheric Teleconnection over Eurasia Induced by Aerosol Radiative Forcing during Boreal Spring

NASA Technical Reports Server (NTRS)

Kim, Maeng-Ki; Lau, William K. M.; Chin, Mian; Kim, Kyu-Myong; Sud, Y. C.; Walker, Greg K.

2006-01-01

The direct effects of aerosols on global and regional climate during boreal spring are investigated based on numerical simulations with the NASA Global Modeling and Assimilation Office finite-volume general circulation model (fvGCM) with Microphyics of Clouds with the Relaxed Arakawa Schubert Scheme (McRAS), using aerosol forcing functions derived from the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The authors find that anomalous atmospheric heat sources induced by absorbing aerosols (dust and black carbon) excite a planetary-scale teleconnection pattern in sea level pressure, temperature, and geopotential height spanning North Africa through Eurasia to the North Pacific. Surface cooling due to direct effects of aerosols is found in the vicinity and downstream of the aerosol source regions, that is, South Asia, East Asia, and northern and western Africa. Significant atmospheric heating is found in regions with large loading of dust (over northern Africa and the Middle East) and black carbon (over Southeast Asia). Paradoxically, the most pronounced feature in aerosol-induced surface temperature is an east west dipole anomaly with strong cooling over the Caspian Sea and warming over central and northeastern Asia, where aerosol concentrations are low. Analyses of circulation anomalies show that the dipole anomaly is a part of an atmospheric teleconnection pattern driven by atmospheric heating anomalies induced by absorbing aerosols in the source regions, but the influence was conveyed globally through barotropic energy dispersion and sustained by feedback processes associated with the regional circulations. The surface temperature signature associated with the aerosol-induced teleconnection bears striking resemblance to the spatial pattern of observed long-term trend in surface temperature over Eurasia. Additionally, the boreal spring wave train pattern is similar to that reported by Fukutomi et al. associated with the boreal summer precipitation seesaw between eastern and western Siberia. The results of this study raise the possibility that global aerosol forcing during boreal spring may play an important role in spawning atmospheric teleconnections that affect regional and global climates.

Intensified ENSO-Driven Precipitation Teleconnections in the Future

NASA Astrophysics Data System (ADS)

Bonfils, C.; Santer, B. D.; Phillips, T. J.; Marvel, K.; Leung, L. R.; Doutriaux, C.

2014-12-01

The El Niño-Southern Oscillation (ENSO) is an important driver of regional hydroclimate variability through far-reaching teleconnections. Most climate models project an increase in the frequency of extreme El Niño events under increased greenhouse-gas (GHG) forcing. However, it is unclear how other aspects of ENSO and ENSO-driven teleconnections will evolve in the future. Here, we identify in 20th century sea-surface temperature (SST) observations a time-invariant ENSO-like (ENSOL) pattern that is largely uncontaminated by GHG forcing. We use this pattern to investigate the future precipitation (P) response to ENSO-like SST anomalies. Models that better capture observed ENSOL characteristics produce P teleconnection patterns that are in better accord with observations and more stationary in the 21st century. We decompose the future P response to ENSOL into the sum of three terms: (1) the change in P mean state, (2) the historical P response to ENSOL, and (3) a future enhancement in the P response to ENSOL. In many regions, this last term can aggravate the P extremes associated with ENSO variability. This simple decomposition allows us to identify regions likely to experience ENSOL-induced P changes that are without precedent in the current climate. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Spatial correlations of interdecadal variation in global surface temperatures

NASA Technical Reports Server (NTRS)

Mann, Michael E.; Park, Jeffrey

1993-01-01

We have analyzed spatial correlation patterns of interdecadal global surface temperature variability from an empirical perspective. Using multitaper coherence estimates from 140-yr records, we find that correlations between hemispheres are significant at about 95 percent confidence for nonrandomness for most of the frequency band in the 0.06-0.24 cyc/yr range. Coherence estimates of pairs of 100-yr grid-point temperature data series near 5-yr period reveal teleconnection patterns consistent with known patterns of ENSO variability. Significant correlated variability is observed near 15 year period, with the dominant teleconnection pattern largely confined to the Northern Hemisphere. Peak-to-peak Delta-T is at about 0.5 deg, with simultaneous warming and cooling of discrete patches on the earth's surface. A global average of this pattern would largely cancel.

Past and future impact of North Atlantic teleconnection patterns on the hydroclimate of the Caspian catchment area in CESM1.2.2 and observations

NASA Astrophysics Data System (ADS)

Nandini, Sri

2017-04-01

The Caspian Sea level has undergone dramatic variations of more than 3 m during the past century with important implications for the life of coastal people, economy and the ecosystem. The origin of these variations as well as future changes in the Caspian water budget are still a matter of debate. In this study, we examine the influence of the major seasonal North Atlantic teleconnection patterns, the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), the Scandinavian pattern (SCA), and the North Sea Caspian Pattern (NCP), on Caspian hydroclimate variability from 1850-2000 CE. Numerical experiments at different atmospheric grid resolutions (2° and 1°) are carried out with the coupled Community Earth System Model (CESM1.2.2). We test model skills under different resolutions through validation against observational data by various statistical methods (Empirical Orthogonal Functions, Taylor diagrams, linear regressions and Spearman rank correlation). Results reveal the strongest simulated signal in winter (DJF) with high explained variances for 1° CESM1.2.2 NAO (39%) and EA (15.7%), similar to observational data. The model is unable to reproduce the SCA pattern in the third EOF, which is found in the observations. The modelled NAO has a strong influence on winter temperature and rainfall over the Caspian catchment area. A strong winter NCP induces above-average 2-meter temperatures over north Caspian region and lower-than-normal precipitation over the eastern Caspian sea. Our study suggests that the 1° version of CESM1.2.2 (with CAM5 atmosphere physics) shows adequate performance with respect to teleconnection maps during the historical period. Lastly, 1° model climate projections (2005-2100 CE) are performed with different Representative Concentration Pathways (RCP 4.5 and RCP 8.5) to examine potential changes in the teleconnection patterns and their influence on the Caspian region.

The interannual variation in monthly temperature over Northeast China during summer

NASA Astrophysics Data System (ADS)

Chen, Wei; Lu, Riyu

2014-05-01

The interannual variations of summer surface air temperature over Northeast China (NEC) were investigated through a month-to-month analysis from May to August. The results suggested that the warmer temperature over NEC is related to a local positive 500-hPa geopotential height anomaly for all four months. However, the teleconnection patterns of atmospheric circulation anomalies associated with the monthly surface air temperature over NEC behave as a distinguished subseasonal variation, although the local positive height anomaly is common from month to month. In May and June, the teleconnection pattern is characterized by a wave train in the upper and middle troposphere from the Indian Peninsula to NEC. This wave train is stronger in June than in May, possibly due to the positive feedback between the wave train and the South Asian rainfall anomaly in June, when the South Asian summer monsoon has been established. In July and August, however, the teleconnection pattern associated with the NEC temperature anomalies is characterized by an East Asia/Pacific (EAP) or Pacific/Japan (PJ) pattern, with the existence of precipitation anomalies over the Philippine Sea and the South China Sea. This pattern is much clearer in July corresponding to the stronger convection over the Philippine Sea compared to that in August.

The North Atlantic-Eurasian teleconnection in summer and its effects on Eurasian climates

NASA Astrophysics Data System (ADS)

Li, Jianping; Ruan, Chengqing

2018-02-01

A teleconnection between the North Atlantic Ocean and the Eurasian continent is suggested by statistical and dynamical analysis of the northern summer 500 hPa geopotential height field. This teleconnection, termed the Atlantic-Eurasian (AEA) teleconnection, has five centers of action, in the subtropical North Atlantic Ocean, northeastern North Atlantic Ocean, Eastern Europe, the Kara Sea, and north China. The AEA index (AEAI) shows that the AEA undergoes a high degree of variability from year to year, and the AEAI has an increasing trend over the last 30 years. Our results suggest that this phenomenon is a large-scale Rossby wave train that originates in the subtropical North Atlantic Ocean. We support this conclusion by the methods of stationary wave ray tracing in non-uniform horizontal basic flow, wave activity flux calculations, and numerical models. The AEA and midlatitude circumglobal teleconnection pattern manifest distinct features at the hemispheric scale, despite the anomalies associated with them bear some similarities in the northeastern North Atlantic and Eastern Europe. Regional climate variations are strongly linked to this AEA along its path through northern Eurasia.

The East Asian Jet Stream and Asian-Pacific-American Climate

NASA Technical Reports Server (NTRS)

Yang, Song; Lau, K.-M.; Kim, K.-M.

2000-01-01

The upper-tropospheric westerly jet stream over subtropical East Asia and western Pacific, often referred to as East Asian Jet (EAJ), is an important atmospheric circulation system in the Asian-Pacific-American (APA) region during winter. It is characterized by variabilities on a wide range of time scales and exerts a strong impact on the weather and climate of the region. On the synoptic scale, the jet stream is closely linked to many phenomena such as cyclogenesis, frontogenesis, blocking, storm track activity, and the development of other atmospheric disturbances. On the seasonal time scale, the variation of the EAJ determines many characteristics of the seasonal transition of the atmospheric circulation especially over East Asia. The variabilities of the EAJ on these time scales have been relatively well documented. It has also been understood since decades ago that the interannual. variability of the EAJ is associated with many climate signals in the APA region. These signals include the persistent anomalies of the East Asian winter monsoon and the changes in diabatic heating and in the Hadley circulation. However, many questions remain for the year-to-year variabilities of the EAJ and their relation to the APA climate. For example, what is the relationship between the EAJ and El Nino/Southern Oscillation (ENSO)? Will the EAJ and ENSO play different roles in modulating the APA climate? How is the jet stream linked to the non-ENSO-related sea surface temperature (SST) anomalies and to the Pacific/North American (PNA) teleconnection pattern?

Characteristics of southern California atmospheric rivers

NASA Astrophysics Data System (ADS)

Harris, Sarah M.; Carvalho, Leila M. V.

2018-05-01

Atmospheric rivers (ARs) are channels of high water vapor flux that transport moisture from low to higher latitudes on synoptic timescales. In areas of topographical variability, ARs may lead to high-intensity precipitation due to orographic forcing. ARs landfalling along North America's west coast are linked to extreme events including those leading to flooding and landslides. In southern California (SCA), proper AR forecasting is important for regional water resources as well as hazard mitigation and as the area's annual precipitation totals occur from relatively few storms per season, any changes to storm frequency and/or intensity may have dramatic consequences. Yet, as most regional AR studies focus on the Pacific Northwest, there is little information about SCA ARs. We develop an algorithm to identify ARs landfalling on North America's west coast between 1979 and 2013 within total precipitable water reanalysis fields. ARs are then categorized according to landfall region. To determine and differentiate the characteristics and spatial distributions of ARs affecting these areas, we examine lag composites of various atmospheric variables for each landfall region. SCA ARs differ from ARs landfalling farther north in the days prior to landfall with the position and amplitude of a trough offshore from the Asian continent and ridge over Alaska, as well as the displacement and eastward extension of the jet core that potentially guides AR moisture southwards. The relationships between AR landfalls and the El Niño/Southern Oscillation (ENSO), the Madden-Julian Oscillation (MJO), and the Pacific/North American Teleconnection Pattern (PNA) are also investigated.

The Impact of Trends in the Large Scale Atmospheric Circulation on Mediterranean Surface Turbulent Heat Fluxes

NASA Technical Reports Server (NTRS)

Romanski, Joy; Hameed, Sultan

2015-01-01

Interannual variations of latent heat fluxes (LHF) and sensible heat fluxes (SHF) over the Mediterranean for the boreal winter season (DJF) show positive trends during 1958-2011. Using reanalysis and satellite-based products, the variability and trends in the heat fluxes are compared with variations in three atmospheric teleconnection patterns: the North Atlantic Oscillation (NAO), the pressure and position of the Azores High (AH), and the East Atlantic-West Russia teleconnection pattern (EAWR). Comparison of correlations between the heat fluxes and teleconnections, along with analysis of composites of surface temperature, humidity, and wind fields for different teleconnection states, demonstrates that the AH explains the heat flux changes more successfully than NAO and EAWR. Trends in pressure and longitude of the Azores High show a strengthening and an eastward shift. Variations of the Azores High occur along an axis defined by lower pressure and westward location at one extreme and higher pressure and eastward location at the other extreme. The shift of the AH from predominance of the low/west state to the high/east state induces trends in Mediterranean Sea surface winds, temperature, and moisture. These, combined with sea surface warming trends, produce trends in wintertime sensible and latent heat fluxes.

Testing the hypothesis of neurodegeneracy in respiratory network function with a priori transected arterially perfused brain stem preparation of rat

PubMed Central

Jones, Sarah E.

2016-01-01

Degeneracy of respiratory network function would imply that anatomically discrete aspects of the brain stem are capable of producing respiratory rhythm. To test this theory we a priori transected brain stem preparations before reperfusion and reoxygenation at 4 rostrocaudal levels: 1.5 mm caudal to obex (n = 5), at obex (n = 5), and 1.5 (n = 7) and 3 mm (n = 6) rostral to obex. The respiratory activity of these preparations was assessed via recordings of phrenic and vagal nerves and lumbar spinal expiratory motor output. Preparations with a priori transection at level of the caudal brain stem did not produce stable rhythmic respiratory bursting, even when the arterial chemoreceptors were stimulated with sodium cyanide (NaCN). Reperfusion of brain stems that preserved the pre-Bötzinger complex (pre-BötC) showed spontaneous and sustained rhythmic respiratory bursting at low phrenic nerve activity (PNA) amplitude that occurred simultaneously in all respiratory motor outputs. We refer to this rhythm as the pre-BötC burstlet-type rhythm. Conserving circuitry up to the pontomedullary junction consistently produced robust high-amplitude PNA at lower burst rates, whereas sequential motor patterning across the respiratory motor outputs remained absent. Some of the rostrally transected preparations expressed both burstlet-type and regular PNA amplitude rhythms. Further analysis showed that the burstlet-type rhythm and high-amplitude PNA had 1:2 quantal relation, with burstlets appearing to trigger high-amplitude bursts. We conclude that no degenerate rhythmogenic circuits are located in the caudal medulla oblongata and confirm the pre-BötC as the primary rhythmogenic kernel. The absence of sequential motor patterning in a priori transected preparations suggests that pontine circuits govern respiratory pattern formation. PMID:26888109

Testing the hypothesis of neurodegeneracy in respiratory network function with a priori transected arterially perfused brain stem preparation of rat.

PubMed

Jones, Sarah E; Dutschmann, Mathias

2016-05-01

Degeneracy of respiratory network function would imply that anatomically discrete aspects of the brain stem are capable of producing respiratory rhythm. To test this theory we a priori transected brain stem preparations before reperfusion and reoxygenation at 4 rostrocaudal levels: 1.5 mm caudal to obex (n = 5), at obex (n = 5), and 1.5 (n = 7) and 3 mm (n = 6) rostral to obex. The respiratory activity of these preparations was assessed via recordings of phrenic and vagal nerves and lumbar spinal expiratory motor output. Preparations with a priori transection at level of the caudal brain stem did not produce stable rhythmic respiratory bursting, even when the arterial chemoreceptors were stimulated with sodium cyanide (NaCN). Reperfusion of brain stems that preserved the pre-Bötzinger complex (pre-BötC) showed spontaneous and sustained rhythmic respiratory bursting at low phrenic nerve activity (PNA) amplitude that occurred simultaneously in all respiratory motor outputs. We refer to this rhythm as the pre-BötC burstlet-type rhythm. Conserving circuitry up to the pontomedullary junction consistently produced robust high-amplitude PNA at lower burst rates, whereas sequential motor patterning across the respiratory motor outputs remained absent. Some of the rostrally transected preparations expressed both burstlet-type and regular PNA amplitude rhythms. Further analysis showed that the burstlet-type rhythm and high-amplitude PNA had 1:2 quantal relation, with burstlets appearing to trigger high-amplitude bursts. We conclude that no degenerate rhythmogenic circuits are located in the caudal medulla oblongata and confirm the pre-BötC as the primary rhythmogenic kernel. The absence of sequential motor patterning in a priori transected preparations suggests that pontine circuits govern respiratory pattern formation. Copyright © 2016 the American Physiological Society.

The North Pacific as a Regulator of Summertime Climate Over North America and the Asian Monsoon

NASA Technical Reports Server (NTRS)

Lau, William K. M.; Wang, H.

2004-01-01

The interannual variability of summertime rainfall over the U.S. may be linked to climate anomalies over Pacific and East Asia through teleconnection patterns that may be components of recurring global climate modes in boreal summer (Lau and Weng 2002). In this study, maintenance of the boreal summer teleconnection patterns is investigated. The particular focus is on the potential effects of North Pacific air-sea interaction on climate anomalies over the U.S. Observational data, reanalysis and outputs of a series of NASA NSIPP AGCM and AGCM coupled to NASA GSFC MLO model experiments are used. Statistical analysis of observations and NSIPP AMIP type simulations indicates that, the interannual variability of observed warm season precipitation over the U.S. is related to SST variation in both tropical and North Pacific, whereas the NSIPP AMIP simulated summertime US. precipitation variation mainly reflects impact of ENS0 in tropical Pacific. This implies the potential importance of air-sea interaction in North Pacific in contributing to the interannual variability of observed summer climate over the U.S. The anomalous atmospheric circulation associated with the dominant summertime teleconnection modes in both observations and NSIPP AMIP simulations are further diagnosed, using stationary wave modeling approach. In observations, for the two dominant modes, both anomalous diabatic heating and anomalous transients significantly contribute to the anomalous circulation. The distributions of the anomalous diabatic heating and transient forcing are quadrature configured over North Pacific and North America, so that both forcings act constructively to maintain the teleconnection patterns. The contrast between observations and NSIPP AMIP simulations from stationary wave modeling diagnosis confirms the previous conclusion based on statistical analysis. To better appreciate the role of extra-tropical air-sea interaction in maintaining the summertime teleconnection pattern, various dynamical and physical fields and their inter- linkage in the series of NSIPP AGCM and AGCM coupled to MLO model experiments are examined in-depth. Based on comparison between different model experiments, we will discuss the physical and dynamical mechanisms through which the air-sea interaction in extratropics, and transient mean flow interactions over the North Pacific, affects interannual variation of U.S. climate during boreal summer.

Predicting summer monsoon of Bhutan based on SST and teleconnection indices

NASA Astrophysics Data System (ADS)

Dorji, Singay; Herath, Srikantha; Mishra, Binaya Kumar; Chophel, Ugyen

2018-02-01

The paper uses a statistical method of predicting summer monsoon over Bhutan using the ocean-atmospheric circulation variables of sea surface temperature (SST), mean sea-level pressure (MSLP), and selected teleconnection indices. The predictors are selected based on the correlation. They are the SST and MSLP of the Bay of Bengal and the Arabian Sea and the MSLP of Bangladesh and northeast India. The Northern Hemisphere teleconnections of East Atlantic Pattern (EA), West Pacific Pattern (WP), Pacific/North American Pattern, and East Atlantic/West Russia Pattern (EA/WR). The rainfall station data are grouped into two regions with principal components analysis and Ward's hierarchical clustering algorithm. A support vector machine for regression model is proposed to predict the monsoon. The model shows improved skills over traditional linear regression. The model was able to predict the summer monsoon for the test data from 2011 to 2015 with a total monthly root mean squared error of 112 mm for region A and 33 mm for region B. Model could also forecast the 2016 monsoon of the South Asia Monsoon Outlook of World Meteorological Organization (WMO) for Bhutan. The reliance on agriculture and hydropower economy makes the prediction of summer monsoon highly valuable information for farmers and various other sectors. The proposed method can predict summer monsoon for operational forecasting.

The effects of monsoons and climate teleconnections on the Niangziguan Karst Spring discharge in North China

NASA Astrophysics Data System (ADS)

Zhang, Juan; Hao, Yonghong; Hu, Bill X.; Huo, Xueli; Hao, Pengmei; Liu, Zhongfang

2017-01-01

Karst aquifers supply drinking water for 25 % of the world's population, and they are, however, vulnerable to climate change. This study is aimed to investigate the effects of various monsoons and teleconnection patterns on Niangziguan Karst Spring (NKS) discharge in North China for sustainable exploration of the karst groundwater resources. The monsoons studied include the Indian Summer Monsoon, the West North Pacific Monsoon and the East Asian Summer Monsoon. The climate teleconnection patterns explored include the Indian Ocean Dipole, E1 Niño Southern Oscillation, and the Pacific Decadal Oscillation. The wavelet transform and wavelet coherence methods are used to analyze the karst hydrological processes in the NKS Basin, and reveal the relations between the climate indices with precipitation and the spring discharge. The study results indicate that both the monsoons and the climate teleconnections significantly affect precipitation in the NKS Basin. The time scales that the monsoons resonate with precipitation are strongly concentrated on the time scales of 0.5-, 1-, 2.5- and 3.5-year, and that climate teleconnections resonate with precipitation are relatively weak and diverged from 0.5-, 1-, 2-, 2.5-, to 8-year time scales, respectively. Because the climate signals have to overcome the resistance of heterogeneous aquifers before reaching spring discharge, with high energy, the strong climate signals (e.g. monsoons) are able to penetrate through aquifers and act on spring discharge. So the spring discharge is more strongly affected by monsoons than the climate teleconnections. During the groundwater flow process, the precipitation signals will be attenuated, delayed, merged, and changed by karst aquifers. Therefore, the coherence coefficients between the spring discharge and climate indices are smaller than those between precipitation and climate indices. Further, the fluctuation of the spring discharge is not coincident with that of precipitation in most situations. Karst spring discharge as a proxy can represent groundwater resource variability at a regional scale, and is more strongly influenced by climate variation.

Review of Tropical-Extratropical Teleconnections on Intraseasonal Time Scales

NASA Astrophysics Data System (ADS)

Stan, Cristiana; Straus, David M.; Frederiksen, Jorgen S.; Lin, Hai; Maloney, Eric D.; Schumacher, Courtney

2017-12-01

The interactions and teleconnections between the tropical and midlatitude regions on intraseasonal time scales are an important modulator of tropical and extratropical circulation anomalies and their associated weather patterns. These interactions arise due to the impact of the tropics on the extratropics, the impact of the midlatitudes on the tropics, and two-way interactions between the regions. Observational evidence, as well as theoretical studies with models of complexity ranging from the linear barotropic framework to intricate Earth system models, suggest the involvement of a myriad of processes and mechanisms in generating and maintaining these interconnections. At this stage, our understanding of these teleconnections is primarily a collection of concepts; a comprehensive theoretical framework has yet to be established. These intraseasonal teleconnections are increasingly recognized as an untapped source of potential subseasonal predictability. However, the complexity and diversity of mechanisms associated with these teleconnections, along with the lack of a conceptual framework to relate them, prevent this potential predictability from being translated into realized forecast skill. This review synthesizes our progress in understanding the observed characteristics of intraseasonal tropical-extratropical interactions and their associated mechanisms, identifies the significant gaps in this understanding, and recommends new research endeavors to address the remaining challenges.

The possible physical mechanism for the EAP-SR co-action

NASA Astrophysics Data System (ADS)

Gong, Zhiqiang; Feng, Guolin; Dogar, Muhammad Mubashar; Huang, Gang

2017-11-01

The anomalous characteristics of summer precipitation and atmospheric circulation in the East Asia-West Pacific Region (EA-WP) associated with the co-action of East Asia/Pacific teleconnection-Silk Road teleconnection (EAP-SR) are investigated in this study. The compositions of EAP-SR phase anomalies can be expressed as pattern I (+ +), pattern II (+ -), pattern III (- -), and pattern IV (- +) using EAP and SR indices. It is found that the spatial distribution of summer precipitation anomalies in EA-WP corresponding to pattern I (III) shows a tripole structure in the meridional direction and a zonal dipole structure in the subtropical region, while pattern II (IV) presents a tripole pattern in meridional direction with compressed and continuous anomalies in the zonal direction over the subtropical region. The similar meridional and zonal structures are also found in the geopotential height anomalies at 500-hPa, as well as wind anomalies and moisture convergence at 850-hPa. Finally, a schematic mechanism for the EAP-SR co-action upon the summer precipitation in EA-WP is built: (1) Pattern I (III) exhibits that the negative (positive) sea surface temperature (SST) anomalies over tropical East Pacific may cause the enhanced (weakened) convective activity dominating the West Pacific, trigger the positive (negative) EAP teleconnection and produce more (less) precipitation. Besides, the negative (positive) SST anomalies over the Indonesia Maritime Continent (IMC) may further weaken (strengthen) anomalous downward (upward) motion over the South China Sea (SCS), cause negative (positive) geopotential height anomalies at the middle troposphere and surrounding regions through the function of the tropical Hadley circulation. Then the negative (positive) geopotential height anomalies could motivate the positive (negative) EAP teleconnection through the northward propagation of wave-activity perturbation. Meanwhile, a positive (negative) geopotential height anomalous pattern over Eastern Europe motivates a Rossby wave train propagation from Western Europe to west-central Asia. This circumstance can cause suppressed (enhanced) convection and less (more) precipitation over northwestern India and Pakistan, which could strengthen the negative (positive) geopotential height and positive (negative) vorticity anomalies over central East Asia, resulting in a negative (positive) SR teleconnection along the Asian jet stream. A positive (negative) lobe over the Korean Peninsula and Japan corresponding to SR overlaps with a positive (negative) lobe of EAP, which strengthens the anomalous phase contrast on both sides of 120°E. Accordingly, summer precipitation anomalies in EA-WP exhibit the meridional tripole pattern and the zonal dipole pattern. (2) Pattern II (IV) indicates that the normal SST anomalies over the tropical East Pacific cause the weak tele-impact on the tropical West Pacific, while the positive (negative) SST anomalies over the IMC will lead to a negative (positive) lobe of EAP over the subtropical region. This circumstance can weaken the positive (negative) lobe of SR over subtropical region, causing compressed and continuous negative (positive) anomalies of 500-hPa geopotential height and positive (negative) surface precipitation anomalies from central East China to Japan.

Spatial patterns of trends and teleconnections in climate indices relevant for Mexican maize

NASA Astrophysics Data System (ADS)

Dewes, C. F.

2013-05-01

This study contributes to the discussion of climate trends in Mexico and the influence of hemispheric-scale variability patterns over the period 1950-2008. Its uniqueness is three-fold. First, the choice of climate indices under scrutiny aims to represent an agro-climatic perspective, geared towards maize in particular because of the major role this crop plays in Mexico's culture, diet, and economy. Second, the spatial resolution and coverage of these findings can be useful for interpretations at the local level (i.e. district or state), yet keeping the broad national picture in perspective. This should be particularly useful to agro-climate forecasting, assessment of impacts, and/or policy development. Third, this study uncovers a dominance of the North Atlantic over the Pacific Ocean in respect to remote influences on trend patterns in Mexico. Trends in precipitation show that east of the central highlands, the rainy season is starting later and becoming drier. The same is occurring along the Pacific coastal plain, but there an increase in extreme events is also observed. For south-central Mexico and the Yucatán, rains not only are starting earlier but intensity and frequency of extreme events are also increasing. In some of these areas dry days are becoming more frequent. Trends in temperature suggest that highlands are warming at faster rates than lowlands, which in some places are actually cooling. Warming in the fall-winter growing season is more pronounced than in the spring-summer growing season. On the other hand, cold spells during mid-summer are becoming more frequent over the highlands. Connections were found between these trends and large-scale variability patterns, namely El Niño Southern Oscillation (ENSO), Pacific North America (PNA), the North Atlantic Oscillation (NAO), and Caribbean sea surface temperatures (SSTs). Interannual variability related to ENSO and the PNA, and trends towards more Niño-like conditions, are associated with increasing precipitation over the Yucatán and a few areas along the southern Pacific coast, and with more dry days - though accompanied by stronger extreme precipitation events - over southwestern Mexico. They are also associated with a delaying start of the rainy season in a narrow area just east of the south-central highlands and higher risk of frost during late-winter up in the highlands. Increasing Caribbean SSTs are associated with increasing temperatures over the mainland and stronger precipitation over the Yucatán. Variability in the NAO and its trend towards more positive phases is associated the drying trend in central Mexico, intensification of precipitation over the northwest, and also increasing temperatures over the entire mainland in both the warm and cold growing seasons. The atmospheric circulation over the Atlantic Ocean and its increasing tropical SSTs, have a larger and broader participation in Mexican trends than is noted with the Pacific counterparts.

PNA binding to the non-template DNA strand interferes with transcription, suggesting a blockage mechanism mediated by R-loop formation.

PubMed

Belotserkovskii, Boris P; Hanawalt, Philip C

2015-11-01

Peptide Nucleic Acids (PNAs) are artificial DNA mimics with superior nucleic acid binding capabilities. T7 RNA polymerase (T7 RNAP) transcription upon encountering PNA bound to the non-template DNA strand was studied in vitro. A characteristic pattern of blockage signals was observed, extending downstream from the PNA binding site, similar to that produced by G-rich homopurine-homopyrimidine (hPu-hPy) sequences and likely caused by R-loop formation. Since blocked transcription complexes in association with stable R-loops may interfere with replication and in some cases trigger apoptosis, targeted R-loop formation might be employed to inactivate selected cells, such as those in tumors, based upon their unique complement of expressed genes. © 2014 The Authors. Molecular Carcinogenesis published by Wiley Periodicals, Inc.

Projections of Flood Risk using Credible Climate Signals in the Ohio River Basin

NASA Astrophysics Data System (ADS)

Schlef, K.; Robertson, A. W.; Brown, C.

2017-12-01

Estimating future hydrologic flood risk under non-stationary climate is a key challenge to the design of long-term water resources infrastructure and flood management strategies. In this work, we demonstrate how projections of large-scale climate patterns can be credibly used to create projections of long-term flood risk. Our study area is the northwest region of the Ohio River Basin in the United States Midwest. In the region, three major teleconnections have been previously demonstrated to affect synoptic patterns that influence extreme precipitation and streamflow: the El Nino Southern Oscillation, the Pacific North American pattern, and the Pacific Decadal Oscillation. These teleconnections are strongest during the winter season (January-March), which also experiences the greatest number of peak flow events. For this reason, flood events are defined as the maximum daily streamflow to occur in the winter season. For each gage in the region, the location parameter of a log Pearson type 3 distribution is conditioned on the first principal component of the three teleconnections to create a statistical model of flood events. Future projections of flood risk are created by forcing the statistical model with projections of the teleconnections from general circulation models selected for skill. We compare the results of our method to the results of two other methods: the traditional model chain (i.e., general circulation model projections to downscaling method to hydrologic model to flood frequency analysis) and that of using the historic trend. We also discuss the potential for developing credible projections of flood events for the continental United States.

Regionally synchronous fires in interior British Columbia, Canada, driven by interannual climate variability and weakly associated with large-scale climate patterns between AD 1600-1900

NASA Astrophysics Data System (ADS)

Harvey, J. E.; Smith, D. J.

2016-12-01

We investigated the influence of climate variability on forest fire occurrence in west central British Columbia (BC), Canada, between AD 1600 and 1900. Fire history was reconstructed at 8 sites in the Cariboo-Chilcotin region and we identified 46 local (fires that affected 1 site) and 16 moderate (fires that affected 2 sites) fires. Preexisting fire history data collected from nearby sites was incorporated to identify 17 regionally synchronous fire years (fires that affected ³ 3 sites). Interannual and multidecadal relationships between fire occurrence and the Palmer Drought Severity Index (PDSI), El Nino Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and the Pacific North American (PNA) pattern were examined, in addition to the effects of phase interactions between ENSO and PDO. We examined multiple reconstructions of PDO and ENSO and utilized three methodological approaches to characterize climate-fire relationships. We found that the influence of interannual climate expressed as PDSI, increasingly synchronized the occurrence of of fires from local to regional fires. Regional fires were associated with anomalously dry, warm conditions in the year of the fire and in years preceding the fire. We also identified an association between local fires and antecedent moisture conditions, where wetter and cooler conditions persisted 2-3 years prior to fire. This finding suggests that moisture-driven fine fuel development and proximity to grasslands could function as key determinants of local (small-scale) fire history parameters. The relationships we identified between regional fires and ENSO, PDO and PNA suggest that large-scale patterns of climate variability exert a weak and/or inconsistent influence over fire activity in west central BC between AD 1600-1900. The strongest relationships between regional fires and large-scale climate patterns were identified when ENSO and PDO were both in positive phases. We also documented a relationship between regional fires and positive years of the PNA pattern. Our findings suggest that long-term fire planning using predictions of large scale climate patterns may be limited in west central BC, however, the consideration of additive phases of ENSO and PDO, and the PNA pattern, may be effective and has been suggested by others in the inland Pacific Northwest.

Predictability of rainfall and teleconnections patterns influencing on Southwest Europe from sea surfaces temperatures

NASA Astrophysics Data System (ADS)

Lorenzo, M. N.; Iglesias, I.; Taboada, J. J.; Gómez-Gesteira, M.; Ramos, A. M.

2009-04-01

This work assesses the possibility of doing a forecast of rainfall and the main teleconnections patterns that influences climate in Southwest Europe by using sea surface temperature anomalies (SSTA). The area under study is located in the NW Iberian Peninsula. This region has a great oceanic influence on its climate and has an important dependency of the water resources. In this way if the different SST patterns are known, the different rainfall situations can be predicted. On the other hand, the teleconnection patterns, which have strong weight on rainfall, are influenced by the SSTA of different areas. In the light of this, the aim of this study is to explore the relationship between global SSTAs, rainfall and the main teleconnection patterns influencing on Europe. The SST data with a 2.0 degree resolution was provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA. A monthly averaged data from 1 January 1951 through December 2006 was considered. The monthly precipitation data from 1951-2006 were obtained from the database CLIMA of the University of Santiago de Compostela with data from the Meteorological State Agency (AEMET) and the Regional Government of Galicia. The teleconnection indices were taken of the Climate Prediction Center of the NOAA between 1950 and 2006. A monthly and seasonal study was analysed considering up to three months of delay in the first case and up to four seasons of delay in the second case. The Pearson product-moment correlation coefficient r was considered to quantify linear associations between SSTA and precipitation and/or SSTA and teleconnection indices. A test for field-significance was applied considering the properties of finiteness and interdependence of the spatial grid to avoid spurious correlations. Analysing the results obtained with the global SSTA and the teleconnection indices, a great number of ocean regions with high correlations can be found. The spatial patterns show very high correlations with Indian Ocean waters which could be related with the Monsoon. Another area with high correlation is Equatorial Pacific Ocean, the area related with the ENSO phenomenon. These SSTAs could be used to forecast rainfall anomalies in spring season in the area of NW Iberian Peninsula. Results show that La Niña years almost always announces dry spring in NW Iberian Peninsula. Nevertheless, El Niño years do not preclude the appearance of wet spring. Because of the progress that has been made in its prediction, the relation between ENSO and climate in NW Iberian Peninsula is of interest with respect to potential seasonal predictability and the results can be extended to the south west of Europe. [1] Lorenzo, M.N. and J. J. Taboada (2005). Influences of atmospheric variability on freshwater input in Galician Rías in winter. Journal of Atmospheric and Ocean Science Vol 10, No 4, 377-387. [2] Lorenzo, M.N. I. Iglesias, J.J. Taboada and M. Gómez-Gesteira. Relationship between monthly rainfall in NW Iberian Peninsula and North Atlantic sea surface temperature. International Journal of Climatology. (Submitted to International Journal of Climatology). [3] Philips, I.D. and J. Thorpe (2006): Icelandic precipitation-North Atlantic sea-surface temperature associations. International Journal of Climatology 26: 1201-1221.

Exploiting teleconnection indices for probabilistic forecasting of drought class transitions in Sicily region (Italy)

NASA Astrophysics Data System (ADS)

Bonaccorso, Brunella; Cancelliere, Antonino

2015-04-01

In the present study two probabilistic models for short-medium term drought forecasting able to include information provided by teleconnection indices are proposed and applied to Sicily region (Italy). Drought conditions are expressed in terms of the Standardized Precipitation-Evapotranspiration Index (SPEI) at different aggregation time scales. More specifically, a multivariate approach based on normal distribution is developed in order to estimate: 1) on the one hand transition probabilities to future SPEI drought classes and 2) on the other hand, SPEI forecasts at a generic time horizon M, as functions of past values of SPEI and the selected teleconnection index. To this end, SPEI series at 3, 4 and 6 aggregation time scales for Sicily region are extracted from the Global SPEI database, SPEIbase , available at Web repository of the Spanish National Research Council (http://sac.csic.es/spei/database.html), and averaged over the study area. In particular, SPEIbase v2.3 with spatial resolution of 0.5° lat/lon and temporal coverage between January 1901 and December 2013 is used. A preliminary correlation analysis is carried out to investigate the link between the drought index and different teleconnection patterns, namely: the North Atlantic Oscillation (NAO), the Scandinavian (SCA) and the East Atlantic-West Russia (EA-WR) patterns. Results of such analysis indicate a strongest influence of NAO on drought conditions in Sicily with respect to other teleconnection indices. Then, the proposed forecasting methodology is applied and the skill in forecasting of the proposed models is quantitatively assessed through the application of a simple score approach and of performance indices. Results indicate that inclusion of NAO index generally enhance model performance thus confirming the suitability of the models for short- medium term forecast of drought conditions.

Using Empirical Orthogonal Teleconnections to Analyze Interannual Precipitation Variability in China

NASA Astrophysics Data System (ADS)

Stephan, C.; Klingaman, N. P.; Vidale, P. L.; Turner, A. G.; Demory, M. E.; Guo, L.

2017-12-01

Interannual rainfall variability in China affects agriculture, infrastructure and water resource management. A consistent and objective method, Empirical Orthogonal Teleconnection (EOT) analysis, is applied to precipitation observations over China in all seasons. Instead of maximizing the explained space-time variance, the method identifies regions in China that best explain the temporal variability in domain-averaged rainfall. It produces known teleconnections, that include high positive correlations with ENSO in eastern China in winter, along the Yangtze River in summer, and in southeast China during spring. New findings include that variability along the southeast coast in winter, in the Yangtze valley in spring, and in eastern China in autumn, are associated with extratropical Rossby wave trains. The same analysis is applied to six climate simulations of the Met Office Unified Model with and without air-sea coupling and at various horizontal resolutions of 40, 90 and 200 km. All simulations reproduce the observed patterns of interannual rainfall variability in winter, spring and autumn; the leading pattern in summer is present in all but one simulation. However, only in two simulations are all patterns associated with the observed physical mechanism. Coupled simulations capture more observed patterns of variability and associate more of them with the correct physical mechanism, compared to atmosphere-only simulations at the same resolution. Finer resolution does not improve the fidelity of these patterns or their associated mechanisms. Evaluating climate models by only geographical distribution of mean precipitation and its interannual variance is insufficient; attention must be paid to associated mechanisms.

Relationships between teleconnection patterns and Turkish climatic extremes

NASA Astrophysics Data System (ADS)

Baltacı, H.; Akkoyunlu, B. O.; Tayanç, M.

2017-12-01

This is a study on the effects of teleconnection patterns (TPs) on the extremes of temperature and precipitation over Turkey. Relationships between five teleconnection patterns, North Atlantic Oscillation (NAO), Arctic Oscillation (AO), East Atlantic-Western Russia (EAWR), East Atlantic (EA), and Scandinavian (SCA) patterns, and 11 climate extreme indices were studied by using 94 uniformly distributed meteorological stations over Turkey for the period of 1965-2014. Analyzing strong positive and negative temperature deviations from the 50-year-winter means shows that such extremes can often be explained by using AO and EAWR patterns. During the negative AO, generally more warm days occur over Black Sea (r = -0.6) and Aegean regions (r = -0.7). This phase of AO also generates above-normal precipitation in the western parts of the Anatolian Peninsula (r around - 0.5). Winter-time negative AO is mainly associated with the presence of a deepened Genoa cyclone over Italy that can transport warm and moist air mass from Mediterranean Sea towards Turkey by strong westerly winds. In contrast, positive EAWR is mainly connected to cold nights over Black Sea (r = 0.6) and Aegean regions (r = 0.6) together with positive precipitation anomalies at the seaside stations of the eastern Black Sea region. On the other hand, when positive EAWR prevails, Azores high-pressure center expands towards continental Europe bringing cold air by strong northerly winds together with higher moisture transport from the Black Sea. These results could pave the way for new possibilities regarding the projection of extremes in downscaling techniques.

Boreal Winter MJO Teleconnection in the Community Atmosphere Model Version 5 with the Unified Convection Parameterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoo, Changhyun; Park, Sungsu; Kim, Daehyun

2015-10-01

The Madden-Julian Oscillation (MJO), the dominant mode of tropical intraseasonal variability, influences weather and climate in the extratropics through atmospheric teleconnection. In this study, two simulations using the Community Atmosphere Model version 5 (CAM5) - one with the default shallow and deep convection schemes and the other with the Unified Convection scheme (UNICON) - are employed to examine the impacts of cumulus parameterizations on the simulation of the boreal wintertime MJO teleconnection in the Northern Hemisphere. We demonstrate that the UNICON substantially improves the MJO teleconnection. When the UNICON is employed, the simulated circulation anomalies associated with the MJO bettermore » resemble the observed counterpart, compared to the simulation with the default convection schemes. Quantitatively, the pattern correlation for the 300-hPa geopotential height anomalies between the simulations and observation increases from 0.07 for the default schemes to 0.54 for the UNICON. These circulation anomalies associated with the MJO further help to enhance the surface air temperature and precipitation anomalies over North America, although room for improvement is still evident. Initial value calculations suggest that the realistic MJO teleconnection with the UNICON is not attributed to the changes in the background wind, but primarily to the improved tropical convective heating associated with the MJO.« less

Relative Contributions of Mean-State Shifts and ENSO-Driven Variability to Precipitation Changes in a Warming Climate

NASA Technical Reports Server (NTRS)

Bonfils, Celine J. W.; Santer, Benjamin D.; Phillips, Thomas J.; Marvel, Kate; Leung, L. Ruby; Doutriaux, Charles; Capotondi, Antonietta

2015-01-01

El Niño-Southern Oscillation (ENSO) is an important driver of regional hydroclimate variability through far-reaching teleconnections. This study uses simulations performed with coupled general circulation models (CGCMs) to investigate how regional precipitation in the twenty-first century may be affected by changes in both ENSO-driven precipitation variability and slowly evolving mean rainfall. First, a dominant, time-invariant pattern of canonical ENSO variability (cENSO) is identified in observed SST data. Next, the fidelity with which 33 state-of-the-art CGCMs represent the spatial structure and temporal variability of this pattern (as well as its associated precipitation responses) is evaluated in simulations of twentieth-century climate change. Possible changes in both the temporal variability of this pattern and its associated precipitation teleconnections are investigated in twenty-first-century climate projections. Models with better representation of the observed structure of the cENSO pattern produce winter rainfall teleconnection patterns that are in better accord with twentieth-century observations and more stationary during the twenty-first century. Finally, the model-predicted twenty-first-century rainfall response to cENSO is decomposed into the sum of three terms: 1) the twenty-first-century change in the mean state of precipitation, 2) the historical precipitation response to the cENSO pattern, and 3) a future enhancement in the rainfall response to cENSO, which amplifies rainfall extremes. By examining the three terms jointly, this conceptual framework allows the identification of regions likely to experience future rainfall anomalies that are without precedent in the current climate.

Relative Contributions of Mean-State Shifts and ENSO-Driven Variability to Precipitation Changes in a Warming Climate

NASA Technical Reports Server (NTRS)

Bonfils, Celine J. W.; Santer, Benjamin D.; Phillips, Thomas J.; Marvel, Kate; Leung, L. Ruby; Doutriaux, Charles; Capotondi, Antonietta

2015-01-01

The El Nino-Southern Oscillation (ENSO) is an important driver of regional hydroclimate variability through far-reaching teleconnections. This study uses simulations performed with Coupled General Circulation Models (CGCMs) to investigate how regional precipitation in the 21st century may be affected by changes in both ENSO-driven precipitation variability and slowly-evolving mean rainfall. First, a dominant, time-invariant pattern of canonical ENSO variability (cENSO) is identified in observed SST data. Next, the fidelity with which 33 state-of-the-art CGCMs represent the spatial structure and temporal variability of this pattern (as well as its associated precipitation responses) is evaluated in simulations of 20th century climate change. Possible changes in both the temporal variability of this pattern and its associated precipitation teleconnections are investigated in 21st century climate projections. Models with better representation of the observed structure of the cENSO pattern produce winter rainfall teleconnection patterns that are in better accord with 20th century observations and more stationary during the 21st century. Finally, the model-predicted 21st century rainfall response to cENSO is decomposed into the sum of three terms: 1) the 21st century change in the mean state of precipitation; 2) the historical precipitation response to the cENSO pattern; and 3) a future enhancement in the rainfall response to cENSO, which amplifies rainfall extremes. By examining the three terms jointly, this conceptual framework allows the identification of regions likely to experience future rainfall anomalies that are without precedent in the current climate.

Observed and Aogcm Simulated Relationships Between us Wind Speeds and Large Scale Modes of Climate Variability

NASA Astrophysics Data System (ADS)

Schoof, J. T.; Pryor, S. C.; Barthelmie, R. J.

2013-12-01

Previous research has indicated that large-scale modes of climate variability, such as El Niño - Southern Oscillation (ENSO), the Arctic Oscillation (AO) and the Pacific-North American pattern (PNA), influence the inter-annual and intra-annual variability of near-surface and upper-level wind speeds over the United States. For example, we have shown that rawinsonde derived wind speeds indicate that 90th percentile of wind speeds at 700 hPa over the Pacific Northwest and Southwestern USA are significantly higher under the negative phase of the PNA, and the Central Plains experiences higher wind speeds at 850 hPa under positive phase Southern Oscillation index while the Northeast exhibits higher wind speeds at 850 hPa under positive phase NAO. Here, we extend this research by further investigating these relationships using both reanalysis products and output from coupled atmosphere-ocean general circulation models (AOGCMs) developed for the 5th Phase of the Coupled Model Intercomparison Project (CMIP5). The research presented has two specific goals. First, we evaluate the AOGCM simulations in terms of their ability to represent the temporal and spatial representations of ENSO, the AO, and the PNA pattern relative to historical observations. The diagnostics used include calculation of the power spectra (and thus representation of the fundamental frequencies of variability) and Taylor diagrams (for comparative assessment of the spatial patterns and their intensities). Our initial results indicate that most AOGCMs produce modes that are qualitatively similar to those observed, but that differ slightly in terms of the spatial pattern, intensity of specific centers of action, and variance explained. Figure 1 illustrates an example of the analysis of the frequencies of variability of two climate modes for the NCEP-NCAR reanalysis (NNR) and a single AOGCM (BCC CSM1). The results show a high degree of similarity in the power spectra but for this AOGCM the variance of the PNA associated with high frequencies are amplified relative to those in NNR. Second, we quantify the observed and AOGCM-simulated relationships between ENSO, AO, and PNA indices and zonal and meridional wind components at multiple levels for the contiguous United States. The results are presented in form of maps displaying the strength of the relationship at different timescales, from daily to annual, and at multiple atmospheric levels, from 10m to 500 mb. The results of the analysis are used to provide context for regional wind climate projections based on 21st century AOGCM simulations.

Precipitation, temperature, and teleconnection signals across the combined North American, Monsoon Asia, and Old World Drought Atlases

NASA Astrophysics Data System (ADS)

Smerdon, J. E.; Baek, S. H.; Coats, S.; Williams, P.; Cook, B.; Cook, E. R.; Seager, R.

2017-12-01

The tree-ring-based North American Drought Atlas (NADA), Monsoon Asia Drought Atlas (MADA), and Old World Drought Atlas (OWDA) collectively yield a near-hemispheric gridded reconstruction of hydroclimate variability over the last millennium. To test the robustness of the large-scale representation of hydroclimate variability across the drought atlases, the joint expression of seasonal climate variability and teleconnections in the NADA, MADA, and OWDA are compared against two global, observation-based PDSI products. Predominantly positive (negative) correlations are determined between seasonal precipitation (surface air temperature) and collocated tree-ring-based PDSI, with average Pearson's correlation coefficients increasing in magnitude from boreal winter to summer. For precipitation, these correlations tend to be stronger in the boreal winter and summer when calculated for the observed PDSI record, while remaining similar for temperature. Notwithstanding these differences, the drought atlases robustly express teleconnection patterns associated with the El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO). These expressions exist in the drought atlas estimates of boreal summer PDSI despite the fact that these modes of climate variability are dominant in boreal winter, with the exception of the Atlantic Multidecadal Oscillation. ENSO and NAO teleconnection patterns in the drought atlases are particularly consistent with their well-known dominant expressions in boreal winter and over the OWDA domain, respectively. Collectively, our findings confirm that the joint Northern Hemisphere drought atlases robustly reflect large-scale patterns of hydroclimate variability on seasonal to multidecadal timescales over the 20th century and are likely to provide similarly robust estimates of hydroclimate variability prior to the existence of widespread instrumental data.

Limitations of BCC_CSM's ability to predict summer precipitation over East Asia and the Northwestern Pacific

NASA Astrophysics Data System (ADS)

Gong, Zhiqiang; Dogar, Muhammad Mubashar Ahmad; Qiao, Shaobo; Hu, Po; Feng, Guolin

2017-09-01

This study examines the ability of the Beijing Climate Center Climate System Model (BCC_CSM) to predict the meridional pattern of summer precipitation over East Asia-Northwest Pacific (EA-NWP) and its East Asia-Pacific (EAP) teleconnection. The differences of summer precipitation modes of the empirical orthogonal function and the bias of atmospheric circulations over EA-NWP are analyzed to determine the reason for the precipitation prediction errors. Results indicate that the BCC_CSM could not reproduce the positive-negative-positive meridional tripole pattern from south to north that differs markedly from that observed over the last 20 years. This failure can be attributed to the bias of the BCC_CSM hindcasts of the summer EAP teleconnection and the low predictability of 500 hPa at the mid-high latitude lobe of the EAP. Meanwhile, the BCC_CSM hindcasts' deficiencies of atmospheric responses to SST anomalies over the Indonesia maritime continent (IMC) resulted in opposite and geographically shifted geopotential anomalies at 500 hPa as well as wind and vorticity anomalies at 850 hPa, rendering the BCC_CSM unable to correctly reproduce the EAP teleconnection pattern. Understanding these two problems will help further improve BCC_CSM's summer precipitation forecasting ability over EA-NWP.

Effect of arachidonic acid metabolites on thymocyte proliferation.

PubMed

Delebassée, S; Gualde, N

1988-01-01

The influences of prostaglandin E2 (PGE2), 15-hydroxyeicosatetraenoic acid (15-HETE) and leukotrienes (LT) on the proliferative response of mature (PNA-) and immature (PNA+) mouse thymocytes was investigated. Both PNA+ and PNA- thymocytes proliferated when cultured with concanavalin A plus interleukin-2. PGE2 in concentrations of 10(-6) to 10(-9) M caused significant inhibition of proliferation of both PNA+ and PNA- thymocytes in these cultures. In contrast, the lipoxygenase products 15-HETE, LTB4, LTC4 and LTD4 caused marked increases in proliferation of PNA+ thymocytes while having no effect on PNA- cells. Therefore, the effect of leukotrienes on thymocyte proliferation depends upon the level of cell maturation and mainly affects immature PNA+ thymocytes.

The extracellular matrix architecture relating to myotendinous pattern formation in the distal part of the developing chick limb: an ultrastructural, histochemical and immunocytochemical analysis.

PubMed

Hurle, J M; Hinchliffe, J R; Ros, M A; Critchlow, M A; Genis-Galvez, J M

1989-07-01

In the later developmental stages (Hamburger and Hamilton, 25-34) the distal part of the chick leg possesses a distinctive extracellular matrix (ECM) architecture which relates to myotendinous patterning. There are two components: firstly, a system of dorsoventrally oriented fibrils which link the two ectodermal surfaces through the undifferentiated distal mesenchyme and secondly, a 'mesenchyme lamina' originates at the basement membrane distally, but proximally runs through the mesoderm, subjacent and parallel to the basement membrane. The 'mesenchyme lamina' appears to be a precursor of developing tendons and is spatially related to the distal tips of the myogenic blocks. As developing tendons form on the inner surface of the lamina at its proximal end, it becomes less distinct and disappears. Further dorsoventral fibrils run from the 'mesenchyme lamina' into the developing condensations and chondrogenic elements of the phalanges. The architecture of the ECM was revealed by silver and lectin staining (peanut and Ricinus communis agglutinins, PNA and RCA I), by immunocytochemistry (for fibronectin, tenascin, collagen type I) and by ultrastructural analysis. Both components stain with silver, PNA following neuraminidase digestion, RCA I, tenascin and collagen type I. However, the dorsoventral fibrils are positive for fibronectin and negative for PNA, while conversely the mesenchyme lamina is positive for PNA but much less so for fibronectin. Tenascin has been shown to be a specialized mesenchyme component of tendons and myotendinous junctions (Chiquet and Fambrough, 1984). Such a basement membrane forming a 'mesenchyme lamina' appears to be unique in epithelial-mesenchymal developing systems and points to an ectodermal role in tendon pattern formation within the mesenchyme. We discuss the possible role of mechanical force in converting the dorsoventral tenascin-positive fibrils into the localized pattern of tendon insertions into the proximal parts of the phalanges. Distally the dorsoventral fibrils may shape the digital plate by pulling together the two ectodermal surfaces. A similar ECM architecture is found in corresponding stages in the developing wing.

Improved Force Fields for Peptide Nucleic Acids with Optimized Backbone Torsion Parameters.

PubMed

Jasiński, Maciej; Feig, Michael; Trylska, Joanna

2018-06-06

Peptide nucleic acids are promising nucleic acid analogs for antisense therapies as they can form stable duplex and triplex structures with DNA and RNA. Computational studies of PNA-containing duplexes and triplexes are an important component for guiding their design, yet existing force fields have not been well validated and parametrized with modern computational capabilities. We present updated CHARMM and Amber force fields for PNA that greatly improve the stability of simulated PNA-containing duplexes and triplexes in comparison with experimental structures and allow such systems to be studied on microsecond time scales. The force field modifications focus on reparametrized PNA backbone torsion angles to match high-level quantum mechanics reference energies for a model compound. The microsecond simulations of PNA-PNA, PNA-DNA, PNA-RNA, and PNA-DNA-PNA complexes also allowed a comprehensive analysis of hydration and ion interactions with such systems.

Twentieth-century atmospheric river activity along the west coasts of Europe and North America: algorithm formulation, reanalysis uncertainty and links to atmospheric circulation patterns

NASA Astrophysics Data System (ADS)

Brands, S.; Gutiérrez, J. M.; San-Martín, D.

2017-05-01

A new atmospheric-river detection and tracking scheme based on the magnitude and direction of integrated water vapour transport is presented and applied separately over 13 regions located along the west coasts of Europe (including North Africa) and North America. Four distinct reanalyses are considered, two of which cover the entire twentieth-century: NOAA-CIRES Twentieth Century Reanalysis v2 (NOAA-20C) and ECMWF ERA-20C. Calculations are done separately for the OND and JFM-season and, for comparison with previous studies, for the ONDJFM-season as a whole. Comparing the AR-counts from NOAA-20C and ERA-20C with a running 31-year window looping through 1900-2010 reveals differences in the climatological mean and inter-annual variability which, at the start of the twentieth-century, are much more pronounced in western North America than in Europe. Correlating European AR-counts with the North Atlantic Oscillation (NAO) reveals a pattern reminiscent of the well-know precipitation dipole which is stable throughout the entire century. A similar analysis linking western North American AR-counts to the North Pacific index (NPI) is hampered by the aforementioned poor reanalysis agreement at the start of the century. During the second half of the twentieth-century, the strength of the NPI-link considerably varies with time in British Columbia and the Gulf of Alaska. Considering the period 1950-2010, AR-counts are then associated with other relevant large-scale circulation indices such as the East Atlantic, Scandinavian, Pacific-North American and West Pacific patterns (EA, SCAND, PNA and WP). Along the Atlantic coastline of the Iberian Peninsula and France, the EA-link is stronger than the NAO-link if the OND season is considered and the SCAND-link found in northern Europe is significant during both seasons. Along the west coast of North America, teleconnections are generally stronger during JFM in which case the NPI-link is significant in any of the five considered subregions, the PNA-link is significant in British Columbia and the Gulf of Alaska and the WP-link is so along the U.S. West Coast. During OND, these links are significant in the Gulf of Alaska only. If AR-counts are calculated upon persistent (instead of instantaneous) ARs, the link to the NAO weakens over the British Isles and western Iberia. For the experimental set-ups most closely mirroring those applied in Lavers et al. (J Geophys Res Atmos 117, 2012. doi: 10.1029/2012JD018027) and Ramos et al. (J Hydrometeorol 16(2):579-597, 2015. doi: 10.1175/JHM-D-14-0103.1), the NAO-links are completely or partly insignificant indicating that the inclusion of the persistence criterion notably alters the results. Visual support for the present study is provided by an exhaustive historical atmospheric river archive built at http://www.meteo.unican.es/atmospheric-rivers.

Risk from drought and extreme heat in Russian wheat production and its relation to atmospheric blocking and teleconnection patterns

NASA Astrophysics Data System (ADS)

Giannakaki, Paraskevi; Calanca, Pierluigi

2017-04-01

Russia has become one of the leading wheat exporters worldwide. Major breakdowns in Russian wheat production induced by extreme weather events are therefore of high significance not only for the domestic but also for the global market. Wheat production in south-western Russia, the main growing area, suffers in particular from the adverse effects of drought and heat waves. For this reason knowledge of the occurrence of this type of extreme events and of the processes that lead to adverse conditions is of paramount importance for risk management. The negative impacts of heat waves and drought are particularly severe when anomalous conditions persist in time. As an example, a blocking event in summer 2010 resulted in one of the warmest and worst drought conditions in Russia's recent history. The latter caused a decline in Russian wheat production by more than 30%, which in turn prompted the Russian government to issue an export ban that lasted until summer 2011. In view of this, the question of course arises of how much of the negative variations in Russian wheat production levels can be explained by blocking events and other features of the large-scale atmospheric circulation. Specific questions are: how often are blocking events over Russia associated with extreme high temperatures and dry conditions? Which of the teleconnection patterns are correlated with drought and heat stress conditions in the area? Answering these questions can contribute to a develop strategies for agricultural risk management. In this contribution we present results of a study that aims at characterizing the occurrence of adverse weather conditions in south-western Russia in relation to atmospheric blocking and teleconnection patterns such as East Atlantic/Western Russia pattern, the Polar/Eurasia pattern, the North Atlantic Oscillation and the Scandinavia pattern. The analysis relies on weather data for 1980-2014 from 130 stations distributed across the wheat production area. The account for similarities in the occurrence of extreme heat, stations are clustered according to 90th percentile of daily maximum temperature. The results indicate that adverse conditions in the area are significantly correlated with the occurrence of blocking events and with the phase of some teleconnection patterns.

Hydrophilic and Cell-Penetrable Pyrrolidinyl Peptide Nucleic Acid via Post-synthetic Modification with Hydrophilic Side Chains.

PubMed

Pansuwan, Haruthai; Ditmangklo, Boonsong; Vilaivan, Chotima; Jiangchareon, Banphot; Pan-In, Porntip; Wanichwecharungruang, Supason; Palaga, Tanapat; Nuanyai, Thanesuan; Suparpprom, Chaturong; Vilaivan, Tirayut

2017-09-20

Peptide nucleic acid (PNA) is a nucleic acid mimic in which the deoxyribose-phosphate was replaced by a peptide-like backbone. The absence of negative charge in the PNA backbone leads to several unique behaviors including a stronger binding and salt independency of the PNA-DNA duplex stability. However, PNA possesses poor aqueous solubility and cannot directly penetrate cell membranes. These are major obstacles that limit in vivo applications of PNA. In previous strategies, the PNA can be conjugated to macromolecular carriers or modified with positively charged side chains such as guanidinium groups to improve the aqueous solubility and cell permeability. In general, a preformed modified PNA monomer was required. In this study, a new approach for post-synthetic modification of PNA backbone with one or more hydrophilic groups was proposed. The PNA used in this study was the conformationally constrained pyrrolidinyl PNA with prolyl-2-aminocyclopentanecarboxylic acid dipeptide backbone (acpcPNA) that shows several advantages over the conventional PNA. The aldehyde modifiers carrying different linkers (alkylene and oligo(ethylene glycol)) and end groups (-OH, -NH 2 , and guanidinium) were synthesized and attached to the backbone of modified acpcPNA by reductive alkylation. The hybrids between the modified acpcPNAs and DNA exhibited comparable or superior thermal stability with base-pairing specificity similar to those of unmodified acpcPNA. Moreover, the modified apcPNAs also showed the improvement of aqueous solubility (10-20 folds compared to unmodified PNA) and readily penetrate cell membranes without requiring any special delivery agents. This study not only demonstrates the practicality of the proposed post-synthetic modification approach for PNA modification, which could be readily applied to other systems, but also opens up opportunities for using pyrrolidinyl PNA in various applications such as intracellular RNA sensing, specific gene detection, and antisense and antigene therapy.

Regime Behavior in Paleo-Reconstructed Streamflow: Attributions to Atmospheric Dynamics, Synoptic Circulation and Large-Scale Climate Teleconnection Patterns

NASA Astrophysics Data System (ADS)

Ravindranath, A.; Devineni, N.

2017-12-01

Studies have shown that streamflow behavior and dynamics have a significant link with climate and climate variability. Patterns of persistent regime behavior from extended streamflow records in many watersheds justify investigating large-scale climate mechanisms as potential drivers of hydrologic regime behavior and streamflow variability. Understanding such streamflow-climate relationships is crucial to forecasting/simulation systems and the planning and management of water resources. In this study, hidden Markov models are used with reconstructed streamflow to detect regime-like behaviors - the hidden states - and state transition phenomena. Individual extreme events and their spatial variability across the basin are then verified with the identified states. Wavelet analysis is performed to examine the signals over time in the streamflow records. Joint analyses of the climatic data in the 20th century and the identified states are undertaken to better understand the hydroclimatic connections within the basin as well as important teleconnections that influence water supply. Compositing techniques are used to identify atmospheric circulation patterns associated with identified states of streamflow. The grouping of such synoptic patterns and their frequency are then examined. Sliding time-window correlation analysis and cross-wavelet spectral analysis are performed to establish the synchronicity of basin flows to the identified synoptic and teleconnection patterns. The Missouri River Basin (MRB) is examined in this study, both as a means of better understanding the synoptic climate controls in this important watershed and as a case study for the techniques developed here. Initial wavelet analyses of reconstructed streamflow at major gauges in the MRB show multidecadal cycles in regime behavior.

Visualizing a possible atmospheric teleconnection associated with UK floods in autumn 2000

NASA Astrophysics Data System (ADS)

Pall, P.; Bensema, K.; Stone, D.; Wehner, M. F.; Bethel, W.; Joy, K.

2012-12-01

Severe floods occurred across England and Wales during the record-wet autumn of the year 2000. Recently Pall et al. (2011) demonstrated that the risk of such floods occurring at that time substantially increased as a result of anthropogenic greenhouse gas emissions, and that the synoptic weather system associated with the floods was a common but anomalously strong 'Scandinavia' atmospheric circulation pattern (a Rossby-wave-like train of tropospheric anomalies in geopotential height, extending from the subtropical Atlantic across Eurasia, with a cyclone over the UK and a strong anticyclone over Scandinavia). Blackburn and Hoskins (2001) suggest that this pattern was itself catalyzed by an anomalous upper-tropospheric flow of air: originating with an ascent of air due to convection over warm sea surface temperatures in the western Tropical Pacific, and ending in a descent of air over the Amazon in the proposed source region of the Scandinavia pattern. However, evidence for this so-called 'teleconnection' is not entirely clear in the idealised climate models they used. Here we use visualization techniques to search for this teleconnection in the simulations generated with the more comprehensive seasonal-forecast-resolution climate model of Pall et al. (2011) -- by identifying anomalous streamflow patterns and using the UV-CDAT software developed at Berkeley Lab to do so. Furthermore, since several thousand simulations were generated (in order to capture the rare flood event), totaling hundreds of GB in size, we use paralleisation techniques to perform this search efficiently.

Summer precipitation prediction in the source region of the Yellow River using climate indices

NASA Astrophysics Data System (ADS)

Yuan, F.

2016-12-01

The source region of the Yellow River contributes about 35% of the total water yield in the Yellow River basin playing an important role in meeting downstream water resources requirements. The summer precipitation from June to September in the source region of the Yellow River accounts for about 70% of the annual total, and its decrease would cause further water shortage problems. Consequently, the objectives of this study are to improve the understanding of the linkages between the precipitation in the source region of the Yellow River and global teleconnection patterns, and to predict the summer precipitation based on revealed teleconnections. Spatial variability of precipitation was investigated based on three homogeneous sub-regions. Principal component analysis and singular value decomposition were used to find significant relations between the precipitation in the source region of the Yellow River and global teleconnection patterns using climate indices. A back-propagation neural network was developed to predict the summer precipitation using significantly correlated climate indices. It was found that precipitation in the study area is positively related to North Atlantic Oscillation, West Pacific Pattern and El Nino Southern Oscillation, and inversely related to Polar Eurasian pattern. Summer precipitation was overall well predicted using these significantly correlated climate indices, and the Pearson correlation coefficient between predicted and observed summer precipitation was in general larger than 0.6. The results are useful for integrated water resources management in the Yellow River basin.

Integrated Remote Sensing and Wavelet Analyses for Screening Short-term Teleconnection Patterns in Northeast America

EPA Science Inventory

Global sea surface temperature (SST) anomalies have a demonstrable effect on vegetation dynamics and precipitation patterns throughout the continental U.S. SST variations have been correlated with greenness (vegetation densities) and precipitation via ocean-atmospheric interactio...

Evaluation of the acrosomal status in Lama glama sperm incubated with acrosome reaction inducers.

PubMed

Carretero, M I; Fumuso, F G; Neild, D M; Giuliano, S M; Cetica, P; Miragaya, M H

2015-09-01

The objectives of this study were to evaluate the effect of different acrosome reaction (AR) inducers on viability and acrosomal status in llama spermatozoa, by using the FITC-PNA/PI technique and evaluate if there is a positive correlation between the FITC-PNA/PI and the Coomassie blue (CB) staining techniques. After incubating twenty ejaculates in 0.1% collagenase the centrifuged pellets were resuspended in TALP-BSA medium. An aliquot was sonicated to remove the acrosomal content (positive control). The rest of the sample was incubated for 3h at 38 °C with 5% CO2 and 100% humidity. Three aliquots were further incubated 1h with one of the following AR inducers: calcium ionophore, ionomycin or progesterone. One without inducers and the other, incubated with dimethyl sulfoxide (vehicle of the inducing agents). Acrosomes were evaluated at time 0 and after 4h incubation. Calcium ionophore was the most potent agent for inducing the AR (67.2 ± 14.4% live+dead AR sperm) (P < 0.05). These samples showed no motility and viability was very low (0-30%). Both ionomycin and progesterone presented significantly higher (P < 0.05) percentages of total AR sperm than the controls, but had similar percentages of dead reacted sperm to the controls. A positive correlation was observed between the intact acrosome FITC-PNA/PI pattern (live+dead sperm) and the acrosome-present CB pattern (r = 0.64; P = 0.000) in all the evaluated samples. the FITC-PNA/PI technique simultaneously evaluates viability and acrosomal status in llama spermatozoa and calcium ionophore could be used as a control of AR. Copyright © 2015 Elsevier B.V. All rights reserved.

Relative contributions of mean-state shifts and ENSO-driven variability to precipitation changes in a warming climate

DOE PAGES

Bonfils, Celine J. W.; Santer, Benjamin D.; Phillips, Thomas J.; ...

2015-12-18

The El Niño–Southern Oscillation (ENSO) is an important driver of regional hydroclimate variability through far-reaching teleconnections. This study uses simulations performed with coupled general circulation models (CGCMs) to investigate how regional precipitation in the twenty-first century may be affected by changes in both ENSO-driven precipitation variability and slowly evolving mean rainfall. First, a dominant, time-invariant pattern of canonical ENSO variability (cENSO) is identified in observed SST data. Next, the fidelity with which 33 state-of-the-art CGCMs represent the spatial structure and temporal variability of this pattern (as well as its associated precipitation responses) is evaluated in simulations of twentieth-century climate change.more » Possible changes in both the temporal variability of this pattern and its associated precipitation teleconnections are investigated in twenty-first-century climate projections. Models with better representation of the observed structure of the cENSO pattern produce winter rainfall teleconnection patterns that are in better accord with twentieth-century observations and more stationary during the twenty-first century. Finally, the model-predicted twenty-first-century rainfall response to cENSO is decomposed into the sum of three terms: 1) the twenty-first-century change in the mean state of precipitation, 2) the historical precipitation response to the cENSO pattern, and 3) a future enhancement in the rainfall response to cENSO, which amplifies rainfall extremes. Lastly, by examining the three terms jointly, this conceptual framework allows the identification of regions likely to experience future rainfall anomalies that are without precedent in the current climate.« less

Maternal peanut exposure during pregnancy and lactation reduces peanut allergy risk in offspring.

PubMed

López-Expósito, Iván; Song, Ying; Järvinen, Kirsi M; Srivastava, Kamal; Li, Xiu-Min

2009-11-01

Maternal allergy is believed to be a risk factor for peanut allergy (PNA) in children. However, there is no direct evidence of maternal transmission of PNA susceptibility, and it is unknown whether maternal peanut exposure affects the development of PNA in offspring. To investigate the influence of maternal PNA on offspring reactions to the first peanut exposure, and whether maternal low-dose peanut exposure during pregnancy and lactation influences these reactions and peanut sensitization in a murine model. Five-week-old offspring of PNA C3H/HeJ mothers (PNA-Ms) were challenged intragastrically with peanut (first exposure), and reactions were determined. In a subset of the experiment, PNA-Ms were fed a low dose of peanut (PNA-M/PN) or not fed peanut (PNA-M/none) during pregnancy and lactation. Their 5-week-old offspring were challenged intragastrically with peanut, and reactions were determined. In another subset of the experiment, offspring of PNA-M/PN or PNA-M/none were sensitized with peanut intragastrically for 6 weeks, and serum peanut-specific antibodies were determined. PNA-M offspring exhibited anaphylactic reactions at first exposure to peanut that were associated with peanut-specific IgG(1) levels and prevented by a platelet activation factor antagonist. In a subset experiment, PNA-M/PN offspring showed significantly reduced first-exposure peanut reactions, increased IgG(2a), and reduced mitogen-stimulated splenocyte cytokine production compared with PNA-M/none offspring. In an additional experiment, PNA-M/PN offspring showed reduction of peanut-specific IgE to active peanut sensitization. We show for the first time maternal transmission of susceptibility to first-exposure peanut reactions and active peanut sensitization. Low-dose peanut exposure during pregnancy and lactation reduced this risk.

Hypomethylation of specific CpG sites in the promoter region of steroidogeneic genes (GATA6 and StAR) in prenatally androgenized rats.

PubMed

Jahromi, Marziyeh Salehi; Hill, Jennifer W; Tehrani, Fahimeh Ramezani; Zadeh-Vakili, Azita

2018-05-30

The methylation level of promoters is one of the most studied and well-known epigenetic mechanisms that programs the amount of gene expression. Over expression of steroidogenesis genes via epigenetic control can result in hypetandrogenism, which is the main endocrine aspect of polycystic ovarian syndrome (PCOS). In the present study we aimed to determine and compare the promoter methylation levels of three steroidogenic genes, CYP17, GATA6 and StAR, in theca cells of prenatally androgenized (PNA) rats to those of controls. Pregnant Wistar rats in the PNA group received 5 mg free testosterone, dissolved in 500 mL solvent, subcutaneously injected on day 20 of pregnancy, while controls were injected with 500 mL of solvent only. Theca cell samples, taken from the ovaries of eight to ten female offspring of both the PNA and control groups, were measured for promoter methylation levels of the aforementioned genes, using the bisulfite sequence PCR (BSP) method. Although the promoters of all three genes were slightly hypomethylated in the PNA group, the differences observed were not significant compared to the control group. The methylation of -520 and -822 positions, in the GATA6 and the StAR promoter respectively, were significantly decreased in the PNA group. The results of this study suggest that alterations in the steroidogenesis pathway after exposure to excess androgen may be a result of changes in the pattern of the methylation of the relevant genes. Copyright © 2017. Published by Elsevier Inc.

Seasonal Prediction of Taiwan's Streamflow Using Teleconnection Patterns

NASA Astrophysics Data System (ADS)

Chen, Chia-Jeng; Lee, Tsung-Yu

2017-04-01

Seasonal streamflow as an integrated response to complex hydro-climatic processes can be subject to activity of prevailing weather systems potentially modulated by large-scale climate oscillations (e.g., El Niño-Southern Oscillation, ENSO). To develop a seamless seasonal forecasting system in Taiwan, this study assesses how significant Taiwan's precipitation and streamflow in different seasons correlate with selected teleconnection patterns. Long-term precipitation and streamflow data in three major precipitation seasons, namely the spring rains (February to April), Mei-Yu (May and June), and typhoon (July to September) seasons, are derived at 28 upstream and 13 downstream catchments in Taiwan. The three seasons depict a complete wet period of Taiwan as well as many regions bearing similar climatic conditions in East Asia. Lagged correlation analysis is then performed to investigate how the precipitation and streamflow data correlate with predominant teleconnection indices at varied lead times. Teleconnection indices are selected only if they show certain linkage with weather systems and activity in the three seasons based on previous literature. For instance, the ENSO and Quasi-Biennial Oscillation, proven to influence East Asian climate across seasons and summer typhoon activity, respectively, are included in the list of climate indices for correlation analysis. Significant correlations found between Taiwan's precipitation and streamflow and teleconnection indices are further examined by a climate regime shift (CRS) test to identify any abrupt changes in the correlations. The understanding of existing CRS is useful for informing the forecasting system of the changes in the predictor-predictand relationship. To evaluate prediction skill in the three seasons and skill differences between precipitation and streamflow, hindcasting experiments of precipitation and streamflow are conducted using stepwise linear regression models. Discussion and suggestions for coping with extreme events in empirical seasonal predictions are also carried out. Findings from this work will contribute to the development of an integrated water resources planning and management system.

Impact of the Dominant Large-scale Teleconnections on Winter Temperature Variability over East Asia

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon; Kim, Hae-Dong

2013-01-01

Monthly mean geopotential height for the past 33 DJF seasons archived in Modern Era Retrospective analysis for Research and Applications reanalysis is decomposed into the large-scale teleconnection patterns to explain their impacts on winter temperature variability over East Asia. Following Arctic Oscillation (AO) that explains the largest variance, East Atlantic/West Russia (EA/WR), West Pacific (WP) and El Nino-Southern Oscillation (ENSO) are identified as the first four leading modes that significantly explain East Asian winter temperature variation. While the northern part of East Asia north of 50N is prevailed by AO and EA/WR impacts, temperature in the midlatitudes (30N-50N), which include Mongolia, northeastern China, Shandong area, Korea, and Japan, is influenced by combined effect of the four leading teleconnections. ENSO impact on average over 33 winters is relatively weaker than the impact of the other three teleconnections. WP impact, which has received less attention than ENSO in earlier studies, characterizes winter temperatures over Korea, Japan, and central to southern China region south of 30N mainly by advective process from the Pacific. Upper level wave activity fluxes reveal that, for the AO case, the height and circulation anomalies affecting midlatitude East Asian winter temperature is mainly located at higher latitudes north of East Asia. Distribution of the fluxes also explains that the stationary wave train associated with EA/WR propagates southeastward from the western Russia, affecting the East Asian winter temperature. Investigation on the impact of each teleconnection for the selected years reveals that the most dominant teleconnection over East Asia is not the same at all years, indicating a great deal of interannual variability. Comparison in temperature anomaly distributions between observation and temperature anomaly constructed using the combined effect of four leading teleconnections clearly show a reasonable consistency between them, demonstrating that the seasonal winter temperature distributions over East Asia are substantially explained by these four large-scale circulation impacts.

Insights into the structural features and stability of peptide nucleic acid with a D-prolyl-2-aminocyclopentane carboxylic acid backbone that binds to DNA and RNA.

PubMed

Poomsuk, Nattawee; Vilaivan, Tirayut; Siriwong, Khatcharin

2018-06-12

Peptide nucleic acid (PNA) is a powerful biomolecule with a wide variety of important applications. In this work, the molecular structures and binding affinity of PNA with a D-prolyl-2-aminocyclopentane carboxylic acid backbone (acpcPNA) that binds to both DNA and RNA were studied using molecular dynamics simulations. The simulated structures of acpcPNA-DNA and acpcPNA-RNA duplexes more closely resembled the typical structures of B-DNA and A-RNA than the corresponding duplexes of aegPNA. The calculated binding free energies are in good agreement with the experimental results that the acpcPNA-DNA duplex is more stable than the acpcPNA-RNA duplex regardless of the base sequences. The results provide further insights in the relationship between structure and stability of this unique PNA system. Copyright © 2018 Elsevier Inc. All rights reserved.

Teleconnection Paths via Climate Network Direct Link Detection.

PubMed

Zhou, Dong; Gozolchiani, Avi; Ashkenazy, Yosef; Havlin, Shlomo

2015-12-31

Teleconnections describe remote connections (typically thousands of kilometers) of the climate system. These are of great importance in climate dynamics as they reflect the transportation of energy and climate change on global scales (like the El Niño phenomenon). Yet, the path of influence propagation between such remote regions, and weighting associated with different paths, are only partially known. Here we propose a systematic climate network approach to find and quantify the optimal paths between remotely distant interacting locations. Specifically, we separate the correlations between two grid points into direct and indirect components, where the optimal path is found based on a minimal total cost function of the direct links. We demonstrate our method using near surface air temperature reanalysis data, on identifying cross-latitude teleconnections and their corresponding optimal paths. The proposed method may be used to quantify and improve our understanding regarding the emergence of climate patterns on global scales.

Non-Watson–Crick interactions between PNA and DNA inhibit the ATPase activity of bacteriophage T4 Dda helicase

PubMed Central

Tackett, Alan J.; Corey, David R.; Raney, Kevin D.

2002-01-01

Peptide nucleic acid (PNA) is a DNA mimic in which the nucleobases are linked by an N-(2-aminoethyl) glycine backbone. Here we report that PNA can interact with single-stranded DNA (ssDNA) in a non-sequence-specific fashion. We observed that a 15mer PNA inhibited the ssDNA-stimulated ATPase activity of a bacteriophage T4 helicase, Dda. Surprisingly, when a fluorescein-labeled 15mer PNA was used in binding studies no interaction was observed between PNA and Dda. However, fluorescence polarization did reveal non-sequence-specific interactions between PNA and ssDNA. Thus, the inhibition of ATPase activity of Dda appears to result from depletion of the available ssDNA due to non-Watson–Crick binding of PNA to ssDNA. Inhibition of the ssDNA-stimulated ATPase activity was observed for several PNAs of varying length and sequence. To study the basis for this phenomenon, we examined self-aggregation by PNAs. The 15mer PNA readily self-aggregates to the point of precipitation. Since PNAs are hydrophobic, they aggregate more than DNA or RNA, making the study of this phenomenon essential for understanding the properties of PNA. Non-sequence-specific interactions between PNA and ssDNA were observed at moderate concentrations of PNA, suggesting that such interactions should be considered for antisense and antigene applications. PMID:11842106

Seasonal flows of international British Columbia-Alaska rivers: The nonlinear influence of ocean-atmosphere circulation patterns

USGS Publications Warehouse

Fleming, Sean W.; Hood, Eran; Dalhke, Helen; O'Neel, Shad

2016-01-01

The northern portion of the Pacific coastal temperate rainforest (PCTR) is one of the least anthropogenically modified regions on earth and remains in many respects a frontier area to science. Rivers crossing the northern PCTR, which is also an international boundary region between British Columbia, Canada and Alaska, USA, deliver large freshwater and biogeochemical fluxes to the Gulf of Alaska and establish linkages between coastal and continental ecosystems. We evaluate interannual flow variability in three transboundary PCTR watersheds in response to El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Arctic Oscillation (AO), and North Pacific Gyre Oscillation (NPGO). Historical hydroclimatic datasets from both Canada and the USA are analyzed using an up-to-date methodological suite accommodating both seasonally transient and highly nonlinear teleconnections. We find that streamflow teleconnections occur over particular seasonal windows reflecting the intersection of specific atmospheric and terrestrial hydrologic processes. The strongest signal is a snowmelt-driven flow timing shift resulting from ENSO- and PDO-associated temperature anomalies. Autumn rainfall runoff is also modulated by these climate modes, and a glacier-mediated teleconnection contributes to a late-summer ENSO-flow association. Teleconnections between AO and freshet flows reflect corresponding temperature and precipitation anomalies. A coherent NPGO signal is not clearly evident in streamflow. Linear and monotonically nonlinear teleconnections were widely identified, with less evidence for the parabolic effects that can play an important role elsewhere. The streamflow teleconnections did not vary greatly between hydrometric stations, presumably reflecting broad similarities in watershed characteristics. These results establish a regional foundation for both transboundary water management and studies of long-term hydroclimatic and environmental change.

Climate teleconnections and recent patterns of human and animal disease outbreaks

USDA-ARS?s Scientific Manuscript database

Recent clusters of outbreaks of mosquito-borne diseases (Rift Valley fever and chikungunya) in Africa and parts of the Indian Ocean islands illustrate how interannual climate variability influences the changing risk patterns of disease outbreaks. Extremes in rainfall (drought and flood) during the p...

Decadal variations in the strength of ENSO teleconnections with precipitation in the western United States

USGS Publications Warehouse

McCabe, G.J.; Dettinger, M.D.

1999-01-01

Changing patterns of correlations between the historical average June-November Southern Oscillation Index (SOI) and October-March precipitation totals for 84 climate divisions in the western US indicate a large amount of variability in SOI/precipitation relations on decadal time scales. Correlations of western US precipitation with SOI and other indices of tropical El Nino-Southern Oscillation (ENSO) processes were much weaker from 1920 to 1950 than during recent decades. This variability in teleconnections is associated with the character of tropical air-sea interactions as indexed by the number of out-of-phase SOI/tropical sea surface temperature (SST) episodes, and with decadal variability in the North Pacific Ocean as indexed by the Pacific Decadal Oscillation (PDO). ENSO teleconnections with precipitation in the western US are strong when SOI and NINO3 are out-of-phase and PDO is negative. ENSO teleconnections are weak when SOI and NINO3 are weakly correlated and PDO is positive. Decadal modes of tropical and North Pacific Ocean climate variability are important indicators of periods when ENSO indices, like SOI, can be used as reliable predictors of winter precipitation in the US.

North Polar Radiative Flux Variability from 2002 Through 2014

NASA Technical Reports Server (NTRS)

Rutan, David; Rose, Fred; Doelling, David; Kato, Seiji; Smith, Bill, Jr.

2017-01-01

NASA's Clouds and the Earth's Radiant Energy System (CERES) project produces the SYN1Deg data product. SYN1deg provides global, 1deg gridded, hourly estimates of Top of Atmosphere (TOA) (CERES observations and calculations) and atmospheric and surface radiative flux (calculations). Examples of 12 year North Polar averages of some variables are shown to the right. Given recent interest in polar science we focus here on TOA and Surface validation of calculated irradiant fluxes. TOA upward longwave irradiance calculations match the CERES observations well both spatially and temporally with correlations remaining strong through PC 6. Compare SYN1Deg Calculations & Meteorological Teleconnections. TOA reflected shortwave irradiance calculations match the CERES observations well both spatially and temporally with correlations remaining string through PC 7. Comparing SYN1Deg calculations to teleconnection patterns requires expanding the area to 30N for EOF analyses. Correlating the Principal Components of various variables to teleconnection time series indicates which variable is most highly correlated with which teleconnection signal. The tables indicate the Pacific North American Oscillation is most correlated to the OLR EOF 1, and the North American Oscillation is correlated most closely to surface LW flux down EOF 1.

[Molecular beacon based PNA-FISH method combined with fluorescence scanning for rapid detection of Listeria monocytogenes].

PubMed

Wu, Shan; Zhang, Xiaofeng; Shuai, Jiangbing; Li, Ke; Yu, Huizhen; Jin, Chenchen

2016-07-04

To simplify the PNA-FISH (Peptide nucleic acid-fluorescence in situ hybridization) test, molecular beacon based PNA probe combined with fluorescence scanning detection technology was applied to replace the original microscope observation to detect Listeria monocytogenes The 5′ end and 3′ end of the L. monocytogenes specific PNA probes were labeled with the fluorescent group and the quenching group respectively, to form a molecular beacon based PNA probe. When PNA probe used for fluorescence scanning and N1 treatment as the control, the false positive rate was 11.4%, and the false negative rate was 0; when N2 treatment as the control, the false positive rate decreased to 4.3%, but the false negative rate rose to 18.6%. When beacon based PNA probe used for fluorescence scanning, taken N1 treatment as blank control, the false positive rate was 8.6%, and the false negative rate was 1.4%; taken N2 treatment as blank control, the false positive rate was 5.7%, and the false negative rate was 1.4%. Compared with PNA probe, molecular beacon based PNA probe can effectively reduce false positives and false negatives. The success rates of hybridization of the two PNA probes were 83.3% and 95.2% respectively; and the rates of the two beacon based PNA probes were 91.7% and 90.5% respectively, which indicated that labeling the both ends of the PNA probe dose not decrease the hybridization rate with the target bacteria. The combination of liquid phase PNA-FISH and fluorescence scanning method, can significantly improve the detection efficiency.

Artificial Informational Polymers and Nanomaterials from Ring-Opening Metathesis Polymerization

NASA Astrophysics Data System (ADS)

James, Carrie Rae

Inspired by naturally occurring polymers (DNA, polypeptides, polysaccharides, etc.) that can self-assemble on the nanoscale into complex, information-rich architectures, we have synthesized nucleic acid based polymers using ROMP. These polymers were synthesized using a graft-through strategy, whereby nucleic acids bearing a strained cyclic olefin were directly polymerized. This is the first example of the graft-through polymerization of nucleic acids. Our approach takes advantage of non-charged peptide nucleic acids (PNAs) as elements to incorporate into ROMP polymer backbones. PNA is a synthetic nucleic acid analogue known for its increased affinity and specificity for complementary DNA or RNA. To accomplish the graft-through polymerization of PNA, we conjugated PNA to strained cyclic olefins using solid phase peptide conjugation chemistry. These PNA monomers were then directly polymerized into homo and block copolymers forming brushes, or comb-like arrangements, of information. Block copolymer amphiphiles of these materials, where the PNA brush served as the hydrophilic portion, were capable of self-assembly into spherical nanoparticles (PNA NPs). These PNA NPs were then studied with respect to their ability to hybridize complementary DNA sequences, as well as their ability to undergo cellular internalization. PNA NPs consisting of densely packed brushes of nucleic acids possessed increased thermal stability when mixed with their complementary DNA sequence, indicating a greater DNA binding affinity over their unpolymerized PNA counterparts. In addition, by arranging the PNA into dense brushes at the surface of the nanoparticle, Cy5.5 labeled PNA NPs were able to undergo cellular internalization into HeLa cells without the need for an additional cellular delivery device. Importantly, cellular internalization of PNA has remained a significant challenge in the literature due to the neutrally charged amino-ethyl glycine backbone of PNA. Therefore, this represents a novel way of facilitating cellular uptake of PNA. This materials strategy represents the first direct polymerization of nucleic acids, and presents a novel method for arranging biological information on the nanoscale at high density in order to confer novel attributes.

Peptide nucleic acid (PNA) is capable of enhancing hammerhead ribozyme activity with long but not with short RNA substrates.

PubMed Central

Jankowsky, E; Strunk, G; Schwenzer, B

1997-01-01

Long RNA substrates are inefficiently cleaved by hammerhead ribozymes in trans. Oligonucleotide facilitators capable of affecting the ribozyme activity by interacting with the substrates at the termini of the ribozyme provide a possibility to improve ribozyme mediated cleavage of long RNA substrates. We have examined the effect of PNA as facilitator in vitro in order to test if even artificial compounds have facilitating potential. Effects of 12mer PNA- (peptide nucleic acid), RNA- and DNA-facilitators of identical sequence were measured with three substrates containing either 942, 452 or 39 nucleotides. The PNA facilitator enhances the ribozyme activity with both, the 942mer and the 452mer substrate to a slightly smaller extent than RNA and DNA facilitators. This effect was observed up to PNA facilitator:substrate ratios of 200:1. The enhancement becomes smaller as the PNA facilitator:substrate ratio exceeds 200:1. With the 39mer substrate, the PNA facilitator decreases the ribozyme activity by more than 100-fold, even at PNA facilitator:substrate ratios of 1:1. Although with long substrates the effect of the PNA facilitator is slightly smaller than the effect of identical RNA or DNA facilitators, PNA may be a more practical choice for potential applications in vivo because PNA is much more resistant to degradation by cellular enzymes. PMID:9207013

Insight into a conformation of the PNA-PNA duplex with (2‧R,4‧R)- and (2‧R,4‧S)-prolyl-(1S,2S)-2-aminocyclopentanecarboxylic acid backbones

NASA Astrophysics Data System (ADS)

Maitarad, Amphawan; Poomsuk, Nattawee; Vilaivan, Chotima; Vilaivan, Tirayut; Siriwong, Khatcharin

2018-04-01

Suitable conformations for peptide nucleic acid (PNA) self-hybrids with (2‧R,4‧R)- and (2‧R,4‧S)-prolyl-(1S,2S)-2-aminocyclopentanecarboxylic acid backbones (namely, acpcPNA and epi-acpcPNA, respectively) were investigated based on molecular dynamics simulations. The results revealed that hybridization of the acpcPNA was observed only in the parallel direction, with a conformation close to the P-type structure. In contrast, self-hybrids of the epi-acpcPNA were formed in the antiparallel and parallel directions; the antiparallel duplex adopted the B-form conformation, and the parallel duplex was between B- and P-forms. The calculated binding energies and the experimental data indicate that the antiparallel epi-acpcPNA self-hybrid was more stable than the parallel duplex.

Thymic lymphocytes. III. Cooperative phenomenon in the proliferation of thymocytes under Con A stimulation.

PubMed

Papiernik, M; Jacobson, J B

1986-01-01

In the present paper, the response of thymocytes to Con A is analyzed in terms of a cooperative phenomenon between medullary thymocytes, cortical thymocytes, thymic accessory cells, and interleukin 2. Medullary thymocytes respond spontaneously to Con A and produce IL-2. The addition of exogenously produced IL-2 enhances their proliferation. Small numbers of cortical (PNA+) thymocytes do not respond to Con A, even in the presence of IL-2-containing supernatant. By increasing the number of PNA+ cells per well, sensitivity to Con A and IL-2 appears. This response may be linked either to the increase in a minor PNA+-responding population and/or to the enhanced contamination by medullary thymocytes and macrophages in non-responding PNA+ thymocyte population. In this hypothesis, either the contaminating cells respond by themselves and/or cooperate with PNA+ cells to induce their proliferation. Coculture of non-responding low numbers of PNA+ thymocytes with Con A- and IL-2-containing supernatant in the presence of PNA- cells containing thymic medullary thymocytes and macrophages always produces a higher response than that of each individual population. These results show that a cooperative phenomenon occurs in the cocultures of PNA+ and PNA- thymic cells. We can show using PNA+ and PNA- thymocytes with different Thy 1 alleles, that indeed both PNA+ and populations participate PNA-thymocytes with different Thy 1 alleles, that indeed both PNA+ and PNA- populations participate in the generation of proliferating cells. We can demonstrate, by lysis experiments with monoclonal antibodies and complement that at the end of coculture, most of the proliferating cells are Lyt 1+, and part are Lyt 2+ or L3T4+. We discuss the fact that the phenotype of the cells after activation does not allow us to deduce the phenotype of their precursors. Lysis of Ia+ cells prior to coculture, reduces the level of the proliferative response but does not modify the percentage of cooperation produced by the coculture. Cooperation with medullary mature thymocytes or the presence of active Ia- accessory cells possibly able to convert to Ia expression during coculture experiments may account for these results.

Fluorous Peptide Nucleic Acids: PNA Analogues with Fluorine in Backbone (γ-CF2-apg-PNA) Enhance Cellular Uptake.

PubMed

Ellipilli, Satheesh; Ganesh, Krishna N

2015-09-18

Fluorous PNA analogues possessing fluorine as inherent part of aminopropylglycine (apg) backbone (γ-CF2-apg PNA) have been synthesized and evaluated for biophysical and cell penetrating properties. These form duplexes of higher thermal stability with cRNA than cDNA, although destabilized compared to duplexes of standard aeg-PNA. Cellular uptake of the fluorinated γ-CF2-apg PNAs in NIH 3T3 and HeLa cells was 2-3-fold higher compared to that of nonfluorinated apg PNA, with NIH 3T3 cells showing better permeability compared to HeLa cells. The backbone fluorinated PNAs, which are first in this class, when combined with other chemical modifications may have potential for future PNA-based antisense agents.

Tumor affinity of radiolabeled peanut agglutinin compared with that of Ga-67 citrate in animal models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yokoyama, K.; Aburano, T.; Watanabe, N.

1985-05-01

Peanut agglutinin (PNA) binds avidly to the immunodominant group of the tumor associated T antigen. The purpose of this study was to evaluate oncodiagnostic potential of radiolabeled PNA in animal models. PNA was labeled with I-125 or I-131 by Iodogen and also with In-111 by cyclic DTPA anhydride. The biological activity of PNA was examined by a hemaglutination titer with a photometer before and after labeling. Animal tumor models used were Lewis Lung Cancer(LLC), B-16 Melanotic Melanoma(MM), Yoshida Sarcoma(YS), Ehrlich Ascites Tumor(EAT and Hepatoma AH109A(HAH). Inflammatory tissue induced by turpentine oil was used as an abscess model. Serial scintigraphic imagesmore » were obtained following IV injections of 100 ..mu..Ci of I-131 or In-111-DTPA-PNA. The tumor affinity of Ga-67 citrate was studied to compare that of radiolabeled PNA. Tissue biodistribution was studied in EAT bearing mice. All of these tumor models except HAH were clearly visible by radiolabeled PNA without subtraction techniques. In the models of LLC and EAT, PNA showed the better accumulation into the tumor tissue than Ga-67 citrate. In YS and MM, PNA represented almost the same accumulation as Ga-67 citrate. The localization of PNA into abscess tissue wasn't found although Ga-67 citrate markedly accumulated into abscess tissue as well as tumor tissue. The clearance of PNA from tumor was slower than those from any other organs. Tumor to muscle ratio was 5.1 at 48hrs. and tumor to blood ratio increased with time to 2.3 at 96hrs. These results suggested that radiolabeled PNA may have a potential in the detection of tumor.« less

The Crystal Structure of Non-Modified and Bipyridine-Modified PNA Duplexes

PubMed Central

Yeh, Joanne I.; Pohl, Ehmke; Truan, Daphne; He, Wei; Sheldrick, George M.; Du, Shoucheng; Achim, Catalina

2011-01-01

Peptide nucleic acid (PNA) is a synthetic analogue of DNA that commonly has an N-aminoethlyl-glycine backbone. The crystal structure of two PNA duplexes, one containing eight standard nucleobase pairs (GGCATCGG)2 (pdb: 3MBS), and the other containing the same nucleobase pairs and a central pair of bipyridine ligands (pdb: 3MBU), has been solved with a resolution of 1.2 Å and 1.05 Å, respectively. The non-modified PNA duplex adopts a P-type helical structure s i m i l a r t o that of previously characterized PNAs. The atomic-level resolution of the structures allowed us to observe for the first time specific modes of interaction between the terminal lysines of the PNA and the backbone and nucleobases situated in the vicinity of the lysines, which are considered an important factor in the induction of a preferred handedness in PNA duplexes. These results support the notion that while PNA typically adopts a P-type helical structure, its flexibility is relatively high. For example, the base pair rise in the bipyridine-containing PNA is the largest measured to date in a PNA homoduplex. The two bipyridines are bulged out of the duplex and are aligned parallel to the minor groove of the PNA. In the case of the bipyridine-containing PNA, two bipyridines from adjacent PNA duplexes form a π-stacked pair that relates the duplexes within the crystal. The bulging out of the bipyridines causes bending of the PNA duplex, which is in contrast to the structure previously reported for biphenyl-modified DNA duplexes in solution, where the biphenyls are π-stacking with adjacent nucleobase pairs and adopt an intrahelical geometry [Johar et al., Chem. Eur. J., 2008, 14, 2080]. This difference shows that relatively small perturbations can significantly impact the relative position of nucleobase analogues in nucleic acid duplexes. PMID:20859960

Recent Advances in Chemical Modification of Peptide Nucleic Acids

PubMed Central

Rozners, Eriks

2012-01-01

Peptide nucleic acid (PNA) has become an extremely powerful tool in chemistry and biology. Although PNA recognizes single-stranded nucleic acids with exceptionally high affinity and sequence selectivity, there is considerable ongoing effort to further improve properties of PNA for both fundamental science and practical applications. The present paper discusses selected recent studies that improve on cellular uptake and binding of PNA to double-stranded DNA and RNA. The focus is on chemical modifications of PNA's backbone and heterocyclic nucleobases. The paper selects representative recent studies and does not attempt to provide comprehensive coverage of the broad and vibrant field of PNA modification. PMID:22991652

Crystal structure of chiral gammaPNA with complementary DNA strand: insights into the stability and specificity of recognition and conformational preorganization.

PubMed

Yeh, Joanne I; Shivachev, Boris; Rapireddy, Srinivas; Crawford, Matthew J; Gil, Roberto R; Du, Shoucheng; Madrid, Marcela; Ly, Danith H

2010-08-11

We have determined the structure of a PNA-DNA duplex to 1.7 A resolution by multiple-wavelength anomalous diffraction phasing method on a zinc derivative. This structure represents the first high-resolution 3D view of a hybrid duplex containing a contiguous chiral PNA strand with complete gamma-backbone modification ("gammaPNA"). Unlike the achiral counterpart, which adopts a random-fold, this particular gammaPNA is already preorganized into a right-handed helix as a single strand. The new structure illustrates the unique characteristics of this modified PNA, possessing conformational flexibility while maintaining sufficient structural integrity to ultimately adopt the preferred P-helical conformation upon hybridization with DNA. The unusual structural adaptability found in the gammaPNA strand is crucial for enabling the accommodation of backbone modifications while constraining conformational states. In conjunction with NMR analysis characterizing the structures and substructures of the individual building blocks, these results provide unprecedented insights into how this new class of chiral gammaPNA is preorganized and stabilized, before and after hybridization with a cDNA strand. Such knowledge is crucial for the future design and development of PNA for applications in biology, biotechnology, and medicine.

Southern Ocean Convection and tropical telleconnections

NASA Astrophysics Data System (ADS)

Marinov, I.; Cabre, A.; Gnanadesikan, A.

2014-12-01

We show that Southern Ocean (SO) temperatures in the latest generation of Earth System Models exhibit two major modes of variation, one driven by deep convection, the other by tropical variability. We perform a CMIP5 model intercomparison to understand why different climate models represent SO variability so differently in long, control simulations. We show that multiyear variability in Southern Ocean sea surface temperatures (SSTs) can in turn influence oceanic and atmospheric conditions in the tropics on short (atmospheric) time-scales. We argue that the strength and pattern of SO-tropical teleconnections depends on the intensity of SO deep convection. Periodic convection in the SO is a feature of most CMIP5 models under preindustrial forcing (deLavergne et al., 2014). Models show a wide distribution in the spatial extent, periodicity and intensity of their SO convection, with some models convecting most of the time, and some showing very little convection. In a highly convective coupled model, we find that multidecadal variability in SO and global SSTs, as well as SO heat storage are driven by Weddell Sea convective variability, with convective decades relatively warm due to the heat released from the deep southern ocean and non-convective decades cold due to the subsurface storage of heat. Furthermore, pulses of SO convection drive SST and sea ice variations, influencing absorbed shortwave and emitted longwave radiation, wind, cloud and precipitation patterns, with climatic implications for the low latitudes via fast atmospheric teleconnections. We suggest that these high-low latitude teleconnection mechanisms are relevant for understanding hiatus decades. Additionally, Southern Ocean deep convection varied significantly during past, natural climate changes such as during the last deglaciation. Weddell Sea open convection was recently weakened, likely as a consequence of anthropogenic forcing and the resulting surface freshening. Our study opens up the tantalizing possibility that such large-scale changes in SO deep convection might have tropical and indeed global implications via atmospheric teleconnections. We advocate the collection of both paleo and modern proxies that can verify these model-derived mechanisms and global teleconnections.

Impact of dynamical regionalization on precipitation biases and teleconnections over West Africa

NASA Astrophysics Data System (ADS)

Gómara, Iñigo; Mohino, Elsa; Losada, Teresa; Domínguez, Marta; Suárez-Moreno, Roberto; Rodríguez-Fonseca, Belén

2018-06-01

West African societies are highly dependent on the West African Monsoon (WAM). Thus, a correct representation of the WAM in climate models is of paramount importance. In this article, the ability of 8 CMIP5 historical General Circulation Models (GCMs) and 4 CORDEX-Africa Regional Climate Models (RCMs) to characterize the WAM dynamics and variability is assessed for the period July-August-September 1979-2004. Simulations are compared with observations. Uncertainties in RCM performance and lateral boundary conditions are assessed individually. Results show that both GCMs and RCMs have trouble to simulate the northward migration of the Intertropical Convergence Zone in boreal summer. The greatest bias improvements are obtained after regionalization of the most inaccurate GCM simulations. To assess WAM variability, a Maximum Covariance Analysis is performed between Sea Surface Temperature and precipitation anomalies in observations, GCM and RCM simulations. The assessed variability patterns are: El Niño-Southern Oscillation (ENSO); the eastern Mediterranean (MED); and the Atlantic Equatorial Mode (EM). Evidence is given that regionalization of the ENSO-WAM teleconnection does not provide any added value. Unlike GCMs, RCMs are unable to precisely represent the ENSO impact on air subsidence over West Africa. Contrastingly, the simulation of the MED-WAM teleconnection is improved after regionalization. Humidity advection and convergence over the Sahel area are better simulated by RCMs. Finally, no robust conclusions can be determined for the EM-WAM teleconnection, which cannot be isolated for the 1979-2004 period. The novel results in this article will help to select the most appropriate RCM simulations to study WAM teleconnections.

Stability of ENSO and Its Tropical Pacific Teleconnections over the Last Millennium

NASA Technical Reports Server (NTRS)

Lewis, Sophie; Legrande, A. N.

2015-01-01

Determining past changes in the amplitude, frequency and teleconnections of the El Nio Southern Oscillation (ENSO) is important for understanding its potential sensitivity to future anthropogenic climate change. Palaeo-reconstructions from proxy records provide long-term information of ENSO interactions with the background climatic state through time. However, it remains unclear how ENSO characteristics have changed through time, and precisely which signals proxies record. Proxy interpretations are underpinned by the assumption of stationarity in relationships between local and remote climates, and often utilise archives from single locations located in the Pacific Ocean to reconstruct ENSO histories. Here, we investigate the stationarity of ENSO teleconnections using the Last Millennium experiment of CMIP5 (Coupled Model Intercomparison Project phase 5) (Taylor et al., 2012). We show that modelled ENSO characteristics vary on decadal- to centennial-scales, resulting from internal variability and external forcings, such as tropical volcanic eruptions. Furthermore, the relationship between ENSO conditions and local climates across the Pacific basin varies throughout the Last Millennium. Results show the stability of teleconnections is regionally dependent and proxies may reveal complex changes in teleconnected patterns, rather than large-scale changes in base ENSO characteristics. As such, proxy insights into ENSO likely require evidence to be synthesised over large spatial areas in order to deconvolve changes occurring in the NINO3.4 region from those pertaining to proxy-relevant local climatic variables. To obtain robust histories of the ENSO and its remote impacts, we recommend interpretations of proxy records should be considered in conjunction with palaeo-reconstructions from within the Central Pacific

Simulation of South-Asian Summer Monsoon in a GCM

NASA Astrophysics Data System (ADS)

Ajayamohan, R. S.

2007-10-01

Major characteristics of Indian summer monsoon climate are analyzed using simulations from the upgraded version of Florida State University Global Spectral Model (FSUGSM). The Indian monsoon has been studied in terms of mean precipitation and low-level and upper-level circulation patterns and compared with observations. In addition, the model's fidelity in simulating observed monsoon intraseasonal variability, interannual variability and teleconnection patterns is examined. The model is successful in simulating the major rainbelts over the Indian monsoon region. However, the model exhibits bias in simulating the precipitation bands over the South China Sea and the West Pacific region. Seasonal mean circulation patterns of low-level and upper-level winds are consistent with the model's precipitation pattern. Basic features like onset and peak phase of monsoon are realistically simulated. However, model simulation indicates an early withdrawal of monsoon. Northward propagation of rainbelts over the Indian continent is simulated fairly well, but the propagation is weak over the ocean. The model simulates the meridional dipole structure associated with the monsoon intraseasonal variability realistically. The model is unable to capture the observed interannual variability of monsoon and its teleconnection patterns. Estimate of potential predictability of the model reveals the dominating influence of internal variability over the Indian monsoon region.

Links between teleconnection patterns and mean temperature in Spain

NASA Astrophysics Data System (ADS)

Ríos-Cornejo, David; Penas, Ángel; Álvarez-Esteban, Ramón; del Río, Sara

2015-10-01

This work describes the relationships between Spanish temperature and four teleconnection patterns with influence on the Iberian Peninsula on monthly, seasonal and annual time scales, using data from 144 meteorological stations. Partial correlation analyses were carried out using Spearman test, and spatial distribution maps of the correlation coefficients were produced with geostatistical interpolation techniques. We regionalize the study area based on homogeneous areas containing weather stations with a similar response of temperatures to the same patterns. The links between the temperature and the patterns are mainly positive; only the correlations with Western Mediterranean Oscillation (WeMO) in the north and west are negative, indicating that WeMO plays an opposed role in temperature behaviour in Spain. In general terms, the four modes exert considerable influence on temperature in February, May and September. The East Atlantic (EA) is the pattern with the strongest influence on temperature in Spain—mainly in the north—except in June. Generally, on the seasonal and annual scales, large significant areas were only observed for the EA. EA and WeMO best account for the mean temperature on the Mediterranean fringe and in northern Spain, while EA and North Atlantic Oscillation largely explain the temperature in the rest of Spain.

In situ characterization of glycans in the urothelium of donkey bladder: evidence of secretion of sialomucins.

PubMed

Desantis, Salvatore; Accogli, Gianluca; Zizza, Sara; Arrighi, Silvana

2013-09-01

The glycoprotein pattern was investigated by lectin histochemistry in the urothelium lining the urinary bladder of the donkey Equus asinus. Tissue sections were stained with a panel of twelve lectins, in combination with saponification and sialidase digestion (K-s). The urinary bladder urothelium has three distinct layers from the basal zone to the lumen consisting of basal, intermediate and superficial cells (umbrella cells). Cytoplasm of basal cells reacted with SNA, PNA, K-s-PNA, GSA I-B4 and Con A showing glycans ending with Neu5Acα2,6Gal/GalNAc, Neu5AcGalβ1,3GalNAc, αGal and with terminal/internal αMan. The cytoplasm of umbrella cells displayed an increase of Neu5AcGalβ1,3GalNAc and the appearance of Neu5AcGalβ1,3GalNAc, Neu5acα2,3Galβ1,4GlcNAc and Neu5AcGalNAc residues (MAL II, K-s-SBA and K-s-HPA staining). Scattered umbrella cells were characterized by glycans terminating with GalNAc binding DBA, SBA and HPA. The mucosa forms folds with a crypt-like appearance where the urothelium shows a different pattern of glycans. The bladder luminal surface stained with K-s-PNA, K-s-DBA, KOH-s-SBA, and K-s-HPA displaying a coating of sialoglycoproteins belonging to O-linked glycans (typical secretory moieties). These findings show that different glycosylation patterns exist along the donkey bladder urothelium, and different sub-populations of umbrella cells are present secreting the sialoglycans which constitute the protective gel layer lining the bladder. Copyright © 2013 Elsevier GmbH. All rights reserved.

Selective recognition of DNA from olive leaves and olive oil by PNA and modified-PNA microarrays

PubMed Central

Rossi, Stefano; Calabretta, Alessandro; Tedeschi, Tullia; Sforza, Stefano; Arcioni, Sergio; Baldoni, Luciana; Corradini, Roberto; Marchelli, Rosangela

2012-01-01

PNA probes for the specific detection of DNA from olive oil samples by microarray technology were developed. The presence of as low as 5% refined hazelnut (Corylus avellana) oil in extra-virgin olive oil (Olea europaea L.) could be detected by using a PNA microarray. A set of two single nucleotide polymorphisms (SNPs) from the Actin gene of Olive was chosen as a model for evaluating the ability of PNA probes for discriminating olive cultivars. Both unmodified and C2-modified PNAs bearing an arginine side-chain were used, the latter showing higher sequence specificity. DNA extracted from leaves of three different cultivars (Ogliarola leccese, Canino and Frantoio) could be easily discriminated using a microarray with unmodified PNA probes, whereas discrimination of DNA from oil samples was more challenging, and could be obtained only by using chiral PNA probes. PMID:22772038

Enzymatic Reaction with Unnatural Substrates: DNA Photolyase (Escherichia coli) Recognizes and Reverses Thymine [2+2] Dimers in the DNA Strand of a DNA/PNA Hybrid Duplex

NASA Astrophysics Data System (ADS)

Ramaiah, Danaboyina; Kan, Yongzhi; Koch, Troels; Orum, Henrik; Schuster, Gary B.

1998-10-01

Peptide nucleic acids (PNA) are mimics with normal bases connected to a pseudopeptide chain that obey Watson--Crick rules to form stable duplexes with itself and natural nucleic acids. This has focused attention on PNA as therapeutic or diagnostic reagents. Duplexes formed with PNA mirror some but not all properties of DNA. One fascinating aspect of PNA biochemistry is their reaction with enzymes. Here we show an enzyme reaction that operates effectively on a PNA/DNA hybrid duplex. A DNA oligonucleotide containing a cis, syn-thymine [2+2] dimer forms a stable duplex with PNA. The hybrid duplex is recognized by photolyase, and irradiation of the complex leads to the repair of the thymine dimer. This finding provides insight into the enzyme mechanism and provides a means for the selective repair of thymine photodimers.

Interannual variations in fire weather, fire extent, and synoptic-scale circulation patterns in northern California and Oregon

Treesearch

Valerie Trouet; Alan H. Taylor; Andrew M. Carleton; Carl N. Skinner

2009-01-01

The Mediterranean climate region on the west coast of the United States is characterized by wet winters and dry summers, and by high fire activity. The importance of synoptic-scale circulation patterns (ENSO, PDO, PNA) on fire-climate interactions is evident in contemporary fire data sets and in pre-Euroamerican tree-ring-based fire records. We investigated how...

Antimicrobial Peptide-PNA Conjugates Selectively Targeting Bacterial Genes

DTIC Science & Technology

2013-07-22

RXR)4XB and (KFF)3K, were previously reported as a potent permeabilizer against E. coli and MRSA cells (Mellbye, 2009). (RW)4D, a small dendrimeric ...lethal concentration (Liu, 2007). Scheme 1. Synthesis of PNA- dendrimer conjugate. (a) (RW)4D-cysteine (b)Free PNA (C) PNA-(RW)4D conjugates

Molecular self-assembly using peptide nucleic acids.

PubMed

Berger, Or; Gazit, Ehud

2017-01-01

Peptide nucleic acids (PNAs) are extensively studied for the control of genetic expression since their design in the 1990s. However, the application of PNAs in nanotechnology is much more recent. PNAs share the specific base-pair recognition characteristic of DNA together with material-like properties of polyamides, both proteins and synthetic polymers, such as Kevlar and Nylon. The first application of PNA was in the form of PNA-amphiphiles, resulting in the formation of either lipid integrated structures, hydrogels or fibrillary assemblies. Heteroduplex DNA-PNA assemblies allow the formation of hybrid structures with higher stability as compared with pure DNA. A systematic screen for minimal PNA building blocks resulted in the identification of guanine-containing di-PNA assemblies and protected guanine-PNA monomer spheres showing unique optical properties. Finally, the co-assembly of PNA with thymine-like three-faced cyanuric acid allowed the assembly of poly-adenine PNA into fibers. In summary, we believe that PNAs represent a new and important family of building blocks which converges the advantages of both DNA- and peptide-nanotechnologies. © 2016 Wiley Periodicals, Inc.

Final Technical Report for DE-SC0005467

DOE Office of Scientific and Technical Information (OSTI.GOV)

Broccoli, Anthony J.

2014-09-14

The objective of this project is to gain a comprehensive understanding of the key atmospheric mechanisms and physical processes associated with temperature extremes in order to better interpret and constrain uncertainty in climate model simulations of future extreme temperatures. To achieve this objective, we first used climate observations and a reanalysis product to identify the key atmospheric circulation patterns associated with extreme temperature days over North America during the late twentieth century. We found that temperature extremes were associated with distinctive signatures in near-surface and mid-tropospheric circulation. The orientations and spatial scales of these circulation anomalies vary with latitude, season,more » and proximity to important geographic features such as mountains and coastlines. We next examined the associations between daily and monthly temperature extremes and large-scale, recurrent modes of climate variability, including the Pacific-North American (PNA) pattern, the northern annular mode (NAM), and the El Niño-Southern Oscillation (ENSO). The strength of the associations are strongest with the PNA and NAM and weaker for ENSO, and also depend upon season, time scale, and location. The associations are stronger in winter than summer, stronger for monthly than daily extremes, and stronger in the vicinity of the centers of action of the PNA and NAM patterns. In the final stage of this project, we compared climate model simulations of the circulation patterns associated with extreme temperature days over North America with those obtained from observations. Using a variety of metrics and self-organizing maps, we found the multi-model ensemble and the majority of individual models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) generally capture the observed patterns well, including their strength and as well as variations with latitude and season. The results from this project indicate that current models are capable of simulating the large-scale meteorological patterns associated with daily temperature extremes and they suggest that such models can be used to evaluate the extent to which changes in atmospheric circulation will influence future changes in temperature extremes.« less

Versatility of peptide nucleic acids (PNAs): role in chemical biology, drug discovery, and origins of life.

PubMed

Sharma, Chiranjeev; Awasthi, Satish Kumar

2017-01-01

This review briefly discussed nomenclature, synthesis, chemistry, and biophysical properties of a plethora of PNA derivatives reported since the discovery of aegPNA. Different synthetic methods and structural analogs of PNA synthesized till date were also discussed. An insight was gained into various chemical, physical, and biological properties of PNA which make it preferable over all other classes of modified nucleic acid analogs. Thereafter, various approaches with special attention to the practical constraints, characteristics, and inherent drawbacks leading to the delay in the development of PNA as gene therapeutic drug were outlined. An explicit account of the successful application of PNA in different areas of research such as antisense and antigene strategies, diagnostics, molecular probes, and so forth was described along with the current status of PNA as gene therapeutic drug. Further, the plausibility of the existence of PNA and its role in primordial chemistry, that is, origin of life was explored in an endeavor to comprehend the mystery and open up its deepest secrets ever engaging and challenging the human intellect. We finally concluded it with a discussion on the future prospects of PNA technology in the field of therapeutics, diagnostics, and origin of life. © 2016 John Wiley & Sons A/S.

Probing of miniPEGγ-PNA-DNA Hybrid Duplex Stability with AFM Force Spectroscopy.

PubMed

Dutta, Samrat; Armitage, Bruce A; Lyubchenko, Yuri L

2016-03-15

Peptide nucleic acids (PNA) are synthetic polymers, the neutral peptide backbone of which provides elevated stability to PNA-PNA and PNA-DNA hybrid duplexes. It was demonstrated that incorporation of diethylene glycol (miniPEG) at the γ position of the peptide backbone increased the thermal stability of the hybrid duplexes (Sahu, B. et al. J. Org. Chem. 2011, 76, 5614-5627). Here, we applied atomic force microscopy (AFM) based single molecule force spectroscopy and dynamic force spectroscopy (DFS) to test the strength and stability of the hybrid 10 bp duplex. This hybrid duplex consisted of miniPEGγ-PNA and DNA of the same length (γ(MP)PNA-DNA), which we compared to a DNA duplex with a homologous sequence. AFM force spectroscopy data obtained at the same conditions showed that the γ(MP)PNA-DNA hybrid is more stable than the DNA counterpart, 65 ± 15 pN vs 47 ± 15 pN, respectively. The DFS measurements performed in a range of pulling speeds analyzed in the framework of the Bell-Evans approach yielded a dissociation constant, koff ≈ 0.030 ± 0.01 s⁻¹ for γ(MP)PNA-DNA hybrid duplex vs 0.375 ± 0.18 s⁻¹ for the DNA-DNA duplex suggesting that the hybrid duplex is much more stable. Correlating the high affinity of γ(MP)PNA-DNA to slow dissociation kinetics is consistent with prior bulk characterization by surface plasmon resonance. Given the growing interest in γ(MP)PNA as well as other synthetic DNA analogues, the use of single molecule experiments along with computational analysis of force spectroscopy data will provide direct characterization of various modifications as well as higher order structures such as triplexes and quadruplexes.

Evaluation of cell-penetrating peptides (CPPs) as vehicles for intracellular delivery of antisense peptide nucleic acid (PNA).

PubMed

Bendifallah, Nadia; Rasmussen, Frank Winther; Zachar, Vladimir; Ebbesen, Peter; Nielsen, Peter E; Koppelhus, Uffe

2006-01-01

Cell-penetrating peptides (CPPs) are characterized by their ability to be internalized in mammalian cells. To investigate the relative potency of CPPs as carriers of medicinally relevant cargo, a positive read-out assay based on the ability of a peptide nucleic acid (PNA) oligomer to promote correct expression of a recombinant luciferase gene was employed. Seven different CPPs were included in the study: Transportan, oligo-arginine (R7-9), pTat, Penetratin, KFF, SynB3, and NLS. The CPP-PNA conjugates were synthesized by different conjugation chemistries: continuous synthesis, maleimide coupling, and ester or disulfide linkage. Under serum-free conditions PNA-SS-Transportan-amide (ortho)-PNA was found to be the most potent conjugate, resulting in maximum luciferase signal at a concentration of 1-2 microM. (D-Arg)9-PNA showed optimal efficacy at 5 microM but gave rise to only one-third of the luciferase signal obtained with the Transportan conjugate. The pTat- and KFF-PNA conjugates showed significantly lower efficacy. The penetratin-, SynB3-. and NLS-PNA conjugates showed only minimal or no activity. Serum was found to have a drastic negative impact on CPP-driven cellular uptake. PNA-SS-Transportan-acid (ortho) and (D-Arg)9-PNA were least sensitive to the presence of serum. Both the chemical nature and, in the case of Transportan, the position of the peptide PNA coupling were found to have a major impact on the transport capacity of the peptides. However, no simple relationship between linker type and antisense activity of the conjugates could be deduced from the data.

Incidence and mortality trends of aspiration pneumonia in Parkinson's disease in the United States, 1979-2010.

PubMed

Akbar, Umer; Dham, Bhavpreet; He, Ying; Hack, Nawaz; Wu, Samuel; Troche, Michelle; Tighe, Patrick; Nelson, Eugene; Friedman, Joseph H; Okun, Michael S

2015-09-01

Careful examination of long-term analyses and trends is essential in understanding the medico-economic burden of this common complication. We sought to describe the long-term (32-year) trends of incidence and mortality in PD patients hospitalized with aspiration pneumonia (AsPNA). Incidence and mortality of AsPNA in hospitalized PD versus non-PD patients was assessed by logistic regression analysis applied to a national database between the years 1979 and 2010. Covariates such as age-decennium, gender, year AsPNA occurred, and the interactions with PD diagnosis were investigated. Rate of AsPNA and mortality over the 32-years was trended and compared. AsPNA occurred in 3.6% of PD patients and 1.0% of non-PD patients. The average mortality for PD patients was less (17% vs. 22%). Long-term (32-year) trends revealed a nearly 10-fold increase in incidence of AsPNA in PD (0.4% in 1979, 4.9% in 2010), decreasing mortality overtime, higher likelihood in males, and increasing average age of AsPNA patients (steeper increase in PD). All p-values<0.05. In regression analysis, each successive year had a slight increase in odds of AsPNA (OR 1.03 in PD, OR1.06 in non-PD). Trends over 32 years revealed a 10-fold increase in AsPNA among PD and non-PD patients, and an associated decrease in mortality. Our data suggest that PD patients are living longer, have slightly more AsPNA, but a lower mortality than was seen in past decades. Further research should investigate the causes of AsPNA in PD, and also potential interventions to decrease its occurrence. Copyright © 2015 Elsevier Ltd. All rights reserved.

Winter Precipitation in North America and the Pacific-North America Pattern in GEOS-S2Sv2 Seasonal Hindcast

NASA Technical Reports Server (NTRS)

Li, Zhao; Molod, Andrea; Schubert, Siegfried

2018-01-01

Reliable prediction of precipitation remains one of the most pivotal and complex challenges in seasonal forecasting. Previous studies show that various large-scale climate modes, such as ENSO, PNA and NAO play significant role in winter precipitation variability over the Northern America. The influences are most pronounced in years of strong indices of such climate modes. This study evaluates model bias, predictability and forecast skills of monthly winter precipitation in GEOS5-S2S 2.0 retrospective forecast from 1981 to 2016, with emphasis on the forecast skill of precipitation over North America during the extreme events of ENSO, PNA and NAO by applying EOF and composite analysis.

PNA containing isocytidine nucleobase: synthesis and recognition of double helical RNA

PubMed Central

Zengeya, Thomas; Li, Ming; Rozners, Eriks

2011-01-01

Peptide nucleic acid (PNA1) containing a 5-methylisocytidine (iC) nucleobase has been synthesized. Triple helix formation between PNA1 and RNA hairpins having variable base pairs interacting with iC was studied using isothermal titration calorimetry. The iC nucleobase recognized the proposed target, C-G inversion in polypurine tract of RNA, with slightly higher affinity than the natural nucleobases, though the sequence selectivity of recognition was low. Compared to non-modified PNA, PNA1 had lower affinity for its RNA target. PMID:21333533

Atlantic Induced Pan-tropical Climate Variability in the Upper-ocean and Atmosphere

NASA Astrophysics Data System (ADS)

Li, X.; Xie, S. P.; Gille, S. T.; Yoo, C.

2016-02-01

During the last three decades, tropical sea surface temperature (SST) exhibited dipole-like trends, with warming over the tropical Atlantic and Indo-Western Pacific but cooling over the Eastern Pacific. The Eastern Pacific cooling has recently been identified as a driver of the global warming hiatus. Previous studies revealed atmospheric bridges between the tropical Pacific, Atlantic, and Indian Ocean, which could potentially contribute to this zonally asymmetric SST pattern. However, the mechanisms and the interactions between these teleconnections remain unclear. To investigate these questions, we performed a `pacemaker' simulation by restoring the tropical Atlantic SST changes in a state-of-the-art climate model - the CESM1. Results show that the Atlantic plays a key role in initiating the tropical-wide teleconnections, and the Atlantic-induced anomalies contribute 55%-75% of the total tropical SST and circulation changes during the satellite era. A hierarchy of oceanic and atmospheric models are then used to investigate the physical mechanisms of these teleconnections: the Atlantic warming enhances atmospheric deep convection, drives easterly wind anomalies over the Indo-Western Pacific through the Kelvin wave, and westerly anomalies over the eastern Pacific as Rossby waves, in line with Gill's solution (Fig1a). These wind changes induce an Indo-Western Pacific warming via the wind-evaporation-SST effect, and this warming intensifies the La Niña-type response in the upper Pacific Ocean by enhancing the easterly trade winds and through the Bjerknes ocean-dynamical processes (Fig1b). The teleconnection finally develops into a tropical-wide SST dipole pattern with an enhanced trade wind and Walker circulation, similar as the observed changes during the satellite era. This mechanism reveals that the tropical ocean basins are more tightly connected than previously thought, and the Atlantic plays a key role in the tropical climate pattern formation and further the global warming hiatus. The tropical Atlantic warming is likely due to radiative forcing and Atlantic meridional overturning circulation (AMOC). Our study suggests that the AMOC may force the decadal variability of the tropical ocean and atmosphere, and thus contributes to the decadal predictability of the global climate.

Voluntary Exercise Improves Estrous Cyclicity in Prenatally Androgenized Female Mice Despite Programming Decreased Voluntary Exercise: Implications for Polycystic Ovary Syndrome (PCOS).

PubMed

Homa, Lori D; Burger, Laura L; Cuttitta, Ashley J; Michele, Daniel E; Moenter, Suzanne M

2015-12-01

Prenatal androgen (PNA) exposure in mice produces a phenotype resembling lean polycystic ovary syndrome. We studied effects of voluntary exercise on metabolic and reproductive parameters in PNA vs vehicle (VEH)-treated mice. Mice (8 wk of age) were housed individually and estrous cycles monitored. At 10 weeks of age, mice were divided into groups (PNA, PNA-run, VEH, VEH-run, n = 8-9/group); those in the running groups received wheels allowing voluntary running. Unexpectedly, PNA mice ran less distance than VEH mice; ovariectomy eliminated this difference. In ovary-intact mice, there was no difference in glucose tolerance, lower limb muscle fiber types, weight, or body composition among groups after 16 weeks of running, although some mitochondrial proteins were mildly up-regulated by exercise in PNA mice. Before running, estrous cycles in PNA mice were disrupted with most days in diestrus. There was no change in cycles during weeks 1-6 of running (10-15 wk of age). In contrast, from weeks 11 to 16 of running, cycles in PNA mice improved with more days in proestrus and estrus and fewer in diestrus. PNA programs reduced voluntary exercise, perhaps mediated in part by ovarian secretions. Exercise without weight loss improved estrous cycles, which if translated could be important for fertility in and counseling of lean women with polycystic ovary syndrome.

Information transfer from DNA to peptide nucleic acids by template-directed syntheses

NASA Technical Reports Server (NTRS)

Schmidt, J. G.; Christensen, L.; Nielsen, P. E.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

1997-01-01

Peptide nucleic acids (PNAs) are analogs of nucleic acids in which the ribose-phosphate backbone is replaced by a backbone held together by amide bonds. PNAs are interesting as models of alternative genetic systems because they form potentially informational base paired helical structures. Oligocytidylates have been shown to act as templates for formation of longer oligomers of G from PNA G2 dimers. In this paper we show that information can be transferred from DNA to PNA. DNA C4T2C4 is an efficient template for synthesis of PNA G4A2G4 using G2 and A2 units as substrates. The corresponding synthesis of PNA G4C2G4 on DNA C4G2C4 is less efficient. Incorporation of PNA T2 into PNA products on DNA C4A2C4 is the least efficient of the three reactions. These results, obtained using PNA dimers as substrates, parallel those obtained using monomeric activated nucleotides.

A Reconfigurable Design and Architecture of the Ethernet and HomePNA3.0 MAC

NASA Astrophysics Data System (ADS)

Khalilydermany, M.; Hosseinghadiry, M.

In this paper a reconfigurable architecture for Ethernet and HomePNA MAC is presented. By using this new architecture, Ethernet and HomePNA reconfigurable network card can be produced. This architecture has been implemented using VHDL language and after that synthesized on a chip. The differences between HomePNA (synchronized and unsynchronized mode) and Ethernet in collision detection mechanism and priority access to media have caused the need to separate architectures for Ethernet and HomePNA, but by using similarities of them, both the Ethernet and the HomePNA can be implemented in a single chip with a little extra hardware. The number of logical elements of the proposed architecture is increased by 19% in compare to when only an Ethernet MAC is implemented

Morphological and glycan features of the camel oviduct epithelium.

PubMed

Accogli, Gianluca; Monaco, Davide; El Bahrawy, Khalid Ahmed; El-Sayed, Ashraf Abd El-Halim; Ciannarella, Francesca; Beneult, Benedicte; Lacalandra, Giovanni Michele; Desantis, Salvatore

2014-07-01

This study describes regional differences in the oviduct of the one-humped camel (Camelus dromedarius) during the growth phase (GP) and the mature phase (MP) of the follicular wave by means of morphometry, scanning electron microscopy (SEM) and glycohistochemistry investigations. Epithelium height significantly increased in the ampulla and decreased in the isthmus passing from the GP to the MP. Under SEM, non-ciliated cells displayed apical blebs (secretory) or short microvilli. Cilia glycocalyx expressed glycans terminating with sialic acid linked α2,6 to Gal/GalNAc (SNA affinity) throughout the oviducts of GP and MP and sialic acid linked α2,3 to Galβ1,3GalNAc (MAL II and KOH-sialidase (K-s)-PNA staining) throughout the MP oviducts. Non-ciliated cells displayed lectin-binding sites from the supra-nuclear cytoplasm to the luminal surface. Ampulla non-ciliated cells showed O-linked (mucin-type) sialoglycans (MAL II and K-s-PNA) during GP and MP and N-linked sialoglycans (SNA) during the MP. Isthmus non-ciliated cells expressed SNA reactivity in GP and MP, also K-s-PNA binders in MP, and MAL II and PNA affinity (Galβ1,3GalNAc) during GP. Galβ1,3GalNAc was sialilated in the non-ciliated cells of GP UTJ. Luminal surface lacked of Galβ1,3GalNAc in GP and MP, whereas it expressed α2,6- and α2,3-linked sialic acids. In GP intraluminal substance reacted with SNA, MAL II, K-s-PNA in ampulla and only with MAL II in the isthmus and UTJ. These results demonstrate that the morphology and the glycan pattern of the camel oviductal epithelium vary during the follicular wave and that could relate to the region-specific functions. Copyright © 2014 Elsevier GmbH. All rights reserved.

Seasonal prediction for hydro-meteorological variables in the Korean Peninsula: Links with atmospheric teleconnections

NASA Astrophysics Data System (ADS)

Yoon, S.

2016-12-01

This study analyzes nonlinear behavior links with atmospheric teleconnections between hydrologic variables and climate indices using statistical models over the Korean Peninsula (KP). The ocean-related major climate factors such as the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) mode in the Tropical Ocean (TO) region were used to analyze the atmospheric teleconnections by principal component analysis (PCA) and a singular spectrum analysis (SSA). The nonlinear lag time correlations between climate indices and hydrological variables are calculated by the Mutual Information (MI) techniques. Results show that teleconnection based nonlinear correlation coefficients (CCs) were higher than linear CCs, ENSO shows a few months of lag time correlation with IOD, which has a direct influence on rainfall and streamflow anomalies in the KP. The precipitation and streamflow in KP shows a significant increasing and decreasing tendency during warm pool (WP) and cold tongue (CT) El Niño decaying years, respectively, while the La Niña year shows slightly above normal conditions. IOD events show significantly decreasing and increasing long-term normal conditions during positive and negative years, respectively. A better understanding of the relationship between climate indices and streamflow can help policy makers prepare for possible options in river discharge pattern changes. Furthermore, these results provide useful information for water managers and end-users to support long-range water resources prediction and water-related management plan.

Protein/oligonucleotide conjugates as a cell specific PNA carrier.

PubMed

Obara, K; Ishihara, T; Akaike, T; Maruyama, A

2001-01-01

We have focused on proteineus ligand conjugate with oligonucleotides (ODNs) as a cell-specific delivery vector for peptide nucleic acids (PNAs). Asialofetuin (AF), a hepatocyte-specific proteineus ligand, was conjugated with ODNs that served as binding sites for PNAs. Succinimidyl-transe-4(N-maleimidylmethyl)-cyclohexane-1-carboxylate (SMCC) modified AF was coupled with 5'-thiolated oligodeoxynucleotide (HS-ODN). The resulting conjugate held PNAs with sequence-specific manner. The PNA/DNA conjugate complex has resistance against nucleases in serum. The efficient release of PNA from the complex was observed when the complex was made in contact with a target nucleotide. PNA uptake to hepatocytes was greatly enhanced when hepatocytes was incubated with PNA/conjugate complex. Free AF thoroughly inhibited PNA uptake with the conjugate, evidencing asialoglycoprotein receptor (ASGP-R) mediated endocytosis to be a major-route for the cellular uptake.

Influence of pendant chiral C(γ)-(alkylideneamino/guanidino) cationic side-chains of PNA backbone on hybridization with complementary DNA/RNA and cell permeability.

PubMed

Jain, Deepak R; Anandi V, Libi; Lahiri, Mayurika; Ganesh, Krishna N

2014-10-17

Intrinsically cationic and chiral C(γ)-substituted peptide nucleic acid (PNA) analogues have been synthesized in the form of γ(S)-ethyleneamino (eam)- and γ(S)-ethyleneguanidino (egd)-PNA with two carbon spacers from the backbone. The relative stabilization (ΔTm) of duplexes from modified cationic PNAs as compared to 2-aminoethylglycyl (aeg)-PNA is better with complementary DNA (PNA:DNA) than with complementary RNA (PNA:RNA). Inherently, PNA:RNA duplexes have higher stability than PNA:DNA duplexes, and the guanidino PNAs are superior to amino PNAs. The cationic PNAs were found to be specific toward their complementary DNA target as seen from their significantly lower binding with DNA having single base mismatch. The differential binding avidity of cationic PNAs was assessed by the displacement of DNA duplex intercalated ethidium bromide and gel electrophoresis. The live cell imaging of amino/guanidino PNAs demonstrated their ability to penetrate the cell membrane in 3T3 and MCF-7 cells, and cationic PNAs were found to be accumulated in the vicinity of the nuclear membrane in the cytoplasm. Fluorescence-activated cell sorter (FACS) analysis of cell permeability showed the efficiency to be dependent upon the nature of cationic functional group, with guanidino PNAs being better than the amino PNAs in both cell lines. The results are useful to design new biofunctional cationic PNA analogues that not only bind RNA better but also show improved cell permeability.

Orientation Preferences of Backbone Secondary Amide Functional Groups in Peptide Nucleic Acid Complexes: Quantum Chemical Calculations Reveal an Intrinsic Preference of Cationic D-Amino Acid-Based Chiral PNA Analogues for the P-form

PubMed Central

Topham, Christopher M.; Smith, Jeremy C.

2007-01-01

Geometric descriptions of nonideal interresidue hydrogen bonding and backbone-base water bridging in the minor groove are established in terms of polyamide backbone carbonyl group orientation from analyses of residue junction conformers in experimentally determined peptide nucleic acid (PNA) complexes. Two types of interresidue hydrogen bonding are identified in PNA conformers in heteroduplexes with nucleic acids that adopt A-like basepair stacking. Quantum chemical calculations on the binding of a water molecule to an O2 base atom in glycine-based PNA thymine dimers indicate that junctions modeled with P-form backbone conformations are lower in energy than a dimer comprising the predominant conformation observed in A-like helices. It is further shown in model systems that PNA analogs based on D-lysine are better able to preorganize in a conformation exclusive to P-form helices than is glycine-based PNA. An intrinsic preference for this conformation is also exhibited by positively charged chiral PNA dimers carrying 3-amino-D-alanine or 4-aza-D-leucine residue units that provide for additional rigidity by side-chain hydrogen bonding to the backbone carbonyl oxygen. Structural modifications stabilizing P-form helices may obviate the need for large heterocycles to target DNA pyrimidine bases via PNA·DNA-PNA triplex formation. Quantum chemical modeling methods are used to propose candidate PNA Hoogsteen strand designs. PMID:17071666

Temporal evolution of the spatial covariability of rainfall in South America

NASA Astrophysics Data System (ADS)

Ciemer, Catrin; Boers, Niklas; Barbosa, Henrique M. J.; Kurths, Jürgen; Rammig, Anja

2017-10-01

The climate of South America exhibits pronounced differences between rainy and dry seasons, associated with specific synoptic features such as the establishment of the South Atlantic convergence zone. Here, we analyze the spatiotemporal correlation structure and in particular teleconnections of daily rainfall associated with these features by means of evolving complex networks. A modification of Pearson's correlation coefficient is introduced to handle the intricate statistical properties of daily rainfall. On this basis, spatial correlation networks are constructed, and new appropriate network measures are introduced in order to analyze the temporal evolution of the networks' characteristics. We particularly focus on the identification of coherent areas of similar rainfall patterns and previously unknown teleconnection structures between remote areas. We show that the monsoon onset is characterized by an abrupt transition from erratic to organized regional connectivity that prevails during the monsoon season, while only the onset times themselves exhibit anomalous large-scale organization of teleconnections. Furthermore, we reveal that the two mega-droughts in the Amazon basin were already announced in the previous year by an anomalous behavior of the connectivity structure.

Enhanced splicing correction effect by an oligo-aspartic acid-PNA conjugate and cationic carrier complexes.

PubMed

Bae, Yun Mi; Kim, Myung Hee; Yu, Gwang Sig; Um, Bong Ho; Park, Hee Kyung; Lee, Hyun-il; Lee, Kang Taek; Suh, Yung Doug; Choi, Joon Sig

2014-02-10

Peptide nucleic acids (PNAs) are synthetic structural analogues of DNA and RNA. They recognize specific cellular nucleic acid sequences and form stable complexes with complementary DNA or RNA. Here, we designed an oligo-aspartic acid-PNA conjugate and showed its enhanced delivery into cells with high gene correction efficiency using conventional cationic carriers, such as polyethylenimine (PEI) and Lipofectamine 2000. The negatively charged oligo-aspartic acid-PNA (Asp(n)-PNA) formed complexes with PEI and Lipofectamine, and the resulting Asp(n)-PNA/PEI and Asp(n)-PNA/Lipofectamine complexes were introduced into cells. We observed significantly enhanced cellular uptake of Asp(n)-PNA by cationic carriers and detected an active splicing correction effect even at nanomolar concentrations. We found that the splicing correction efficiency of the complex depended on the kind of the cationic carriers and on the number of repeating aspartic acid units. By enhancing the cellular uptake efficiency of PNAs, these results may provide a novel platform technology of PNAs as bioactive substances for their biological and therapeutic applications. Copyright © 2013 Elsevier B.V. All rights reserved.

The efficacy of oral and subcutaneous antigen-specific immunotherapy in murine cow's milk- and peanut allergy models.

PubMed

Vonk, Marlotte M; Wagenaar, Laura; Pieters, Raymond H H; Knippels, Leon M J; Willemsen, Linette E M; Smit, Joost J; van Esch, Betty C A M; Garssen, Johan

2017-01-01

Antigen-specific immunotherapy (AIT) is a promising therapeutic approach for both cow's milk allergy (CMA) and peanut allergy (PNA), but needs optimization in terms of efficacy and safety. Compare oral immunotherapy (OIT) and subcutaneous immunotherapy (SCIT) in murine models for CMA and PNA and determine the dose of allergen needed to effectively modify parameters of allergy. Female C3H/HeOuJ mice were sensitized intragastrically (i.g.) to whey or peanut extract with cholera toxin. Mice were treated orally (5 times/week) or subcutaneously (3 times/week) for three consecutive weeks. Hereafter, the acute allergic skin response, anaphylactic shock symptoms and body temperature were measured upon intradermal (i.d.) and intraperitoneal (i.p.) challenge, and mast cell degranulation was measured upon i.g. challenge. Allergen-specific IgE, IgG1 and IgG2a were measured in serum at different time points. Single cell suspensions derived from lymph organs were stimulated with allergen to induce cytokine production and T cell phenotypes were assessed using flow cytometry. Both OIT and SCIT decreased clinically related signs upon challenge in the CMA and PNA model. Interestingly, a rise in allergen-specific IgE was observed during immunotherapy, hereafter, treated mice were protected against the increase in IgE caused by allergen challenge. Allergen-specific IgG1 and IgG2a increased due to both types of AIT. In the CMA model, SCIT and OIT reduced the percentage of activated Th2 cells and increased the percentage of activated Th1 cells in the spleen. OIT increased the percentage of regulatory T cells (Tregs) and activated Th2 cells in the MLN. Th2 cytokines IL-5, IL-13 and IL-10 were reduced after OIT, but not after SCIT. In the PNA model, no differences were observed in percentages of T cell subsets. SCIT induced Th2 cytokines IL-5 and IL-10, whereas OIT had no effect. We have shown clinical protection against allergic manifestations after OIT and SCIT in a CMA and PNA model. Although similar allergen-specific antibody patterns were observed, differences in T cell and cytokine responses were shown. Whether these findings are related to a different mechanism of AIT in CMA and PNA needs to be elucidated.

The influence of ENSO, PDO and PNA on secular rainfall variations in Hawai`i

NASA Astrophysics Data System (ADS)

Frazier, Abby G.; Elison Timm, Oliver; Giambelluca, Thomas W.; Diaz, Henry F.

2017-11-01

Over the last century, significant declines in rainfall across the state of Hawai`i have been observed, and it is unknown whether these declines are due to natural variations in climate, or manifestations of human-induced climate change. Here, a statistical analysis of the observed rainfall variability was applied as first step towards better understanding causes for these long-term trends. Gridded seasonal rainfall from 1920 to 2012 is used to perform an empirical orthogonal function (EOF) analysis. The leading EOF components are correlated with three indices of natural climate variations (El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Pacific North American (PNA)), and multiple linear regression (MLR) is used to model the leading components with climate indices. PNA is the dominant mode of wet season (November-April) variability, while ENSO is most significant in the dry season (May-October). To assess whether there is an anthropogenic influence on rainfall, two methods are used: a linear trend term is included in the MLR, and pattern correlation coefficients (PCC) are calculated between recent rainfall trends and future changes in rainfall projected by downscaling methods. PCC results indicate that recent observed rainfall trends in the wet season are positively correlated with future expected changes in rainfall, while dry season PCC results do not show a clear pattern. The MLR results, however, show that the trend term adds significantly to model skill only in the dry season. Overall, MLR and PCC results give weak and inconclusive evidence for detection of anthropogenic signals in the observed rainfall trends.

Teleconnections in the Presence of Climate Change: A Case Study of the Annular Modes

NASA Astrophysics Data System (ADS)

Gerber, Edwin; Baldwin, Mark

2010-05-01

Long model integrations of future and past climates present a problem for defining teleconnection patterns through Empirical Orthogonal Function (EOF) or correlation analysis when trends in the underlying climate begin to dominate the covariance structure. Similar issues may soon appear in observations as the record becomes longer, especially if climate trends accelerate. The Northern and Southern Annular Modes provide a prime example, because the poleward shift of the jet streams strongly projects onto these patterns, particularly in the Southern Hemisphere. Climate forecasts of the 21st century by chemistry climate models provide a case study. Computation of the annular modes in these long data sets with secular trends requires refinement of the standard definition of the annular mode, and a more robust procedure that allows for slowly varying trends is established and verified. The new procedure involves two key changes. First, the global mean geopotential height is removed at each time step before computing anomalies. This is particularly important high in the atmosphere, where seasonal variations in geopotential height become significant, and filters out trends due to changes in the temperature structure of the atmosphere. Pattern definition can be very sensitive near the tropopause, as regions of the atmosphere that used to be more of stratospheric character begin to take on tropospheric characteristics as the tropopause rises. The second change is to define anomalies relative to a slowly evolving seasonal climatology, so that the covariance structure reflects internal variability. Once these changes are accounted for, it is found that the zonal mean variability of the atmosphere stays remarkably constant, despite significant changes in the baseline climate forecast for the rest of the century. This stability of the internal variability makes it possible to relate trends in climate to teleconnections.

The Mean State and Inter-annual Variability of East Asian Summer Monsoon in CMIP5 Coupled Models: Does Air-Sea Coupling Improve the Simulations?

NASA Astrophysics Data System (ADS)

Zhou, T.; Song, F.

2014-12-01

The climatology and inter-annual variability of East Asian summer monsoon (EASM) simulated by 34 Coupled Model Intercomparison Project phase 5 (CMIP5) coupled general circulation models (CGCMs) are evaluated. To estimate the role of air-sea coupling, 17 CGCMs are compared to their corresponding atmospheric general circulation models (AGCMs). The climatological low-level monsoon circulation and mei-yu/changma/baiu rainfall band are improved in CGCMs from AGCMs. The improvement is at the cost of the local cold sea surface temperature (SST) biases in CGCMs, since they decrease the surface evaporation and enhance the circulation. The inter-annual EASM pattern is evaluated by a skill formula and the highest/lowest 8 models are selected to investigate the skill origins. The observed Indian Ocean (IO) warming, tropical eastern Indian Ocean (TEIO) rainfall anomalies and Kelvin wave response are captured well in high-skill models, while these features are not present in low-skill models. Further, the differences in the IO warming between high-skill and low-skill models are rooted in the preceding ENSO simulation. Hence, the IO-WPAC teleconnection is important for CGCMs, similar to AGCMs. However, compared to AGCMs, the easterly anomalies in the southern flank of the WPAC make the TEIO warmer in CGCMs by reducing the climatological monsoon westerlies and decreasing the surface evaporation. The warmer TEIO induces the stronger precipitation anomalies and intensifies the teleconnection. Hence, the inter-annual EASM pattern is better simulated in CGCMs than that in AGCMs. Key words: CMIP5, CGCMs, air-sea coupling, AGCMs, inter-annual EASM pattern, ENSO, IO-WPAC teleconnection

Possible teleconnections between East and South Asian summer monsoon precipitation in projected future climate change

NASA Astrophysics Data System (ADS)

Woo, Sumin; Singh, Gyan Prakash; Oh, Jai-Ho; Lee, Kyoung-Min

2018-01-01

The present paper examined the teleconnections between two huge Asian summer monsoon components (South and East Asia) during three time slices in future: near-(2010-2039), mid-(2040-2069) and far-(2070-2100) futures under the RCP4.5 and RCP8.5 scenarios. For this purpose, a high-resolution atmospheric general circulation model is used and integrated at 40 km horizontal resolution. To get more insight into the relationships between the two Asian monsoon components, we have studied the spatial displaying correlation coefficients (CCs) pattern of precipitation over the entire Asian monsoon region with that of South Asia and three regions of East Asia (North China, Korea-Japan and Southern China) separately during the same three time slices. The possible factors responsible for these teleconnections are explored by using mean sea level pressure (MSLP) and wind fields at 850 hPa. The CC pattern of precipitation over South Asia shows an in-phase relationship with North China and an out-of-phase relationship with Korea-Japan, while precipitation variations over Korea-Japan and Southern China exhibit an out-of-phase relationship with South Asia. The CCs analysis between the two Asian blocks during different time slices shows the strongest CCs during the near and far future with the RCP8.5 scenario. The CC pattern of precipitation over Korea-Japan and Southern China with the wind (at 850 hPa) and MSLP fields indicate that the major parts of the moisture over Korea-Japan gets transported from the west Pacific along the western limb of NPSH, while the moisture over Southern China comes from the Bay of Bengal and South China Seas for good monsoon activity.

A Decadal-scale Air-sea Interaction Theory for North Atlantic Multidecadal Variability: the NAT-NAO-AMOC-AMO Coupled Mode and Its Remote Influences

NASA Astrophysics Data System (ADS)

Li, Jianping; Sun, Cheng; Jin, Fei-Fei

2017-04-01

ABSTRACT North Atlantic region shows prominent multidecadal variability. Observational analysis shows that the North Atlantic Oscillation (NAO) leads the oceanic Atlantic Multidecadal Oscillation (AMO) by 15-20 years and the latter also leads the former by around 15 years. The mechanisms are investigated using simulations from a fully coupled model, and a NATNAO-AMOC-AMO Coupled Mode is proposed to explain the multidecadal variability in North Atlantic region. The NAT-NAO-AMO-AMOC coupled mode has important remote influences on regional climates. Observational analysis identifies a significant in-phase relationship between the AMV and Siberian warm season (May to October) precipitation. The physical mechanism for this relationship is investigated using both observations and numerical simulations. North Atlantic sea surface temperature (SST) warming associated with the positive AMV phase can excite an eastward propagating wave train response across the entire Eurasian continent, which includes an east-west dipole structure over Siberia. The dipole then leads to anomalous southerly winds bringing moisture northward to Siberia; the precipitation increases correspondingly. Furthermore, a prominent teleconnection pattern of multidecadal variability of cold season (November to April) upper-level atmospheric circulation over North Africa and Eurasia (NA-EA) is revealed by empirical orthogonal function analysis of the Twentieth Century Reanalysis data, and this teleconnection pattern is referred to as the Africa-Asia multidecadal teleconnection pattern (AAMT). A strong inphase relationship is observed between the AAMT and Atlantic multidecadal variability (AMV) and this connection is mainly due to Rossby wave dynamics. The AAMT acts as an atmospheric bridge conveying the influence of AMV onto the downstream multidecadal climate variability.

Photodissociation of pernitric acid (HO2NO2) at 248 nm

NASA Technical Reports Server (NTRS)

Macleod, Helene; Smith, Gregory P.; Golden, David M.

1989-01-01

The photodissociation of pernitric acid (PNA) was studied at 248 nm. The quantum yield for production of OH radicals is 34 + or - 16 percent. The yield of OH from PNA was measured relative to that of H2O2. The translational and rotational energy content of the OH photofragment from PNA was characterized. A fluorescent emission was also observed and characterized. It is attributed to electronically excited NO2 produced in the PNA photodissociation. A maximum yield of 30 percent for NO2 production was determined. The intensity of this emission, and a mass spectrometric peak at m/e = 33, were found to be useful means of characterizing the purity of the PNA sample.

Global changes of extreme coastal wave energy fluxes triggered by intensified teleconnection patterns

NASA Astrophysics Data System (ADS)

Mentaschi, Lorenzo; Vousdoukas, Michalis I.; Voukouvalas, Evangelos; Dosio, Alessandro; Feyen, Luc

2017-03-01

In this study we conducted a comprehensive modeling analysis to identify global trends in extreme wave energy flux (WEF) along coastlines in the 21st century under a high emission pathway (Representative Concentration Pathways 8.5). For the end of the century, results show a significant increase up to 30% in 100 year return level WEF for the majority of the coastal areas of the southern temperate zone, while in the Northern Hemisphere large coastal areas are characterized by a significant negative trend. We show that the most significant long-term trends of extreme WEF can be explained by intensification of teleconnection patterns such as the Antarctic Oscillation, El Niño-Southern Oscillation, and North Atlantic Oscillation. The projected changes will have broad implications for ocean engineering applications and disaster risk management. Especially low-lying coastal countries in the Southern Hemisphere will be particularly vulnerable due to the combined effects of projected relative sea level rise and more extreme wave activities.

Climate Drivers of Spatiotemporal Variability of Precipitation in the Source Region of Yangtze River

NASA Astrophysics Data System (ADS)

Du, Y.; Berndtsson, R.; An, D.; Yuan, F.

2017-12-01

Variability of precipitation regime has significant influence on the environment sustainability in the source region of Yangtze River, especially when the vegetation degradation and biodiversity reduction have already occurred. Understanding the linkage between variability of local precipitation and global teleconnection patterns is essential for water resources management. Based on physical reasoning, indices of the climate drivers can provide a practical way of predicting precipitation. Due to high seasonal variability of precipitation, climate drivers of the seasonal precipitation also varies. However, few reports have gone through the teleconnections between large scale patterns with seasonal precipitation in the source region of Yangtze River. The objectives of this study are therefore (1) assessment of temporal trend and spatial variability of precipitation in the source region of Yangtze River; (2) identification of climate indices with strong influence on seasonal precipitation anomalies; (3) prediction of seasonal precipitation based on revealed climate indices. Principal component analysis and Spearman rank correlation were used to detect significant relationships. A feed-forward artificial neural network(ANN) was developed to predict seasonal precipitation using significant correlated climate indices. Different influencing climate indices were revealed for precipitation in each season, with significant level and lag times. Significant influencing factors were selected to be the predictors for ANN model. With correlation coefficients between observed and simulated precipitation over 0.5, the results were eligible to predict the precipitation of spring, summer and winter using teleconnections, which can improve integrated water resources management in the source region of Yangtze River.

Negative ions of p-nitroaniline: Photodetachment, collisions, and ab initio calculations

NASA Astrophysics Data System (ADS)

Smith, Byron H.; Buonaugurio, Angela; Chen, Jing; Collins, Evan; Bowen, Kit H.; Compton, Robert N.; Sommerfeld, Thomas

2013-06-01

The structures of parent anion, M-, and deprotonated molecule, [M-H]-, anions of the highly polar p-nitroaniline (pNA) molecule are studied experimentally and theoretically. Photoelectron spectroscopy (PES) of the parent anion is employed to estimate the adiabatic electron affinity (EAa = 0.75 ± 0.1 eV) and vertical detachment energy (VDE = 1.1 eV). These measured energies are in good agreement with computed values of 0.73 eV for the EAa and the range of 0.85 to 1.0 eV for the VDE at the EOM-CCSD/Aug-cc-pVTZ level. Collision induced dissociation (CID) of deprotonated pNA, [pNA - H]-, with argon yielded [pNA - H - NO]- (i.e., rearrangement to give loss of NO) with a threshold energy of 2.36 eV. Calculations of the energy difference between [pNA - H]- and [pNA - H - NO]- give 1.64 eV, allowing an estimate of a 0.72 eV activation barrier for the rearrangement reaction. Direct dissociation of [pNA - H]- yielding NO_2^ - occurs at a threshold energy of 3.80 eV, in good agreement with theory (between 3.39 eV and 4.30 eV). As a result of the exceedingly large dipole moment for pNA (6.2 Debye measured in acetone), we predict two dipole-bound states, one at ˜110 meV and an excited state at 2 meV. No dipole-bound states are observed in the photodetachment experiments due the pronounced mixing between states with dipole-bound and valence character similar to what has been observed in other nitro systems. For the same reason, dipole-bound states are expected to provide highly efficient "doorway states" for the formation of the pNA- valence anion, and these states should be observable as resonances in the reverse process, that is, in the photodetachment spectrum of pNA- near the photodetachment threshold.

Negative ions of p-nitroaniline: photodetachment, collisions, and ab initio calculations.

PubMed

Smith, Byron H; Buonaugurio, Angela; Chen, Jing; Collins, Evan; Bowen, Kit H; Compton, Robert N; Sommerfeld, Thomas

2013-06-21

The structures of parent anion, M(-), and deprotonated molecule, [M-H](-), anions of the highly polar p-nitroaniline (pNA) molecule are studied experimentally and theoretically. Photoelectron spectroscopy (PES) of the parent anion is employed to estimate the adiabatic electron affinity (EAa = 0.75 ± 0.1 eV) and vertical detachment energy (VDE = 1.1 eV). These measured energies are in good agreement with computed values of 0.73 eV for the EAa and the range of 0.85 to 1.0 eV for the VDE at the EOM-CCSD∕Aug-cc-pVTZ level. Collision induced dissociation (CID) of deprotonated pNA, [pNA - H](-), with argon yielded [pNA - H - NO](-) (i.e., rearrangement to give loss of NO) with a threshold energy of 2.36 eV. Calculations of the energy difference between [pNA - H](-) and [pNA - H - NO](-) give 1.64 eV, allowing an estimate of a 0.72 eV activation barrier for the rearrangement reaction. Direct dissociation of [pNA - H](-) yielding NO2(-) occurs at a threshold energy of 3.80 eV, in good agreement with theory (between 3.39 eV and 4.30 eV). As a result of the exceedingly large dipole moment for pNA (6.2 Debye measured in acetone), we predict two dipole-bound states, one at ~110 meV and an excited state at 2 meV. No dipole-bound states are observed in the photodetachment experiments due the pronounced mixing between states with dipole-bound and valence character similar to what has been observed in other nitro systems. For the same reason, dipole-bound states are expected to provide highly efficient "doorway states" for the formation of the pNA(-) valence anion, and these states should be observable as resonances in the reverse process, that is, in the photodetachment spectrum of pNA(-) near the photodetachment threshold.

Peptide Nucleic Acid Array for Detection of Point Mutations in Hepatitis B Virus Associated with Antiviral Resistance ▿ †

PubMed Central

Jang, Hyunjung; Kim, Jihyun; Choi, Jae-jin; Son, Yeojin; Park, Heekyung

2010-01-01

The detection of antiviral-resistant hepatitis B virus (HBV) mutations is important for monitoring the response to treatment and for effective treatment decisions. We have developed an array using peptide nucleic acid (PNA) probes to detect point mutations in HBV associated with antiviral resistance. PNA probes were designed to detect mutations associated with resistance to lamivudine, adefovir, and entecavir. The PNA array assay was sensitive enough to detect 102 copies/ml. The PNA array assay was able to detect mutants present in more than 5% of the virus population when the total HBV DNA concentration was greater than 104 copies/ml. We analyzed a total of 68 clinical samples by this assay and validated its usefulness by comparing results to those of the sequencing method. The PNA array correctly identified viral mutants and has high concordance (98.3%) with direct sequencing in detecting antiviral-resistant mutations. Our results showed that the PNA array is a rapid, sensitive, and easily applicable assay for the detection of antiviral-resistant mutation in HBV. Thus, the PNA array is a useful and powerful diagnostic tool for the detection of point mutations or polymorphisms. PMID:20573874

Mutations in M2 alter the selectivity of the mouse nicotinic acetylcholine receptor for organic and alkali metal cations

PubMed Central

1992-01-01

We measured the permeability ratios (PX/PNa) of 3 wild-type, 1 hybrid, 2 subunit-deficient, and 22 mutant nicotinic receptors expressed in Xenopus oocytes for alkali metal and organic cations using shifts in the bi-ionic reversal potential of the macroscopic current. Mutations at three positions (2', 6', 10') in M2 affected ion selectivity. Mutations at position 2' (alpha Thr244, beta Gly255, gamma Thr253, delta Ser258) near the intracellular end of M2 changed the organic cation permeability ratios as much as twofold and reduced PCs/PNa and PK/PNa by 16-18%. Mutations at positions 6' and 10' increased the glycine ethyl ester/Na+ and glycine methyl ester/Na+ permeability ratios. Two subunit alterations also affected selectivity: omission of the delta subunit reduced PCs/PNa by 16%, and substitution of Xenopus delta for mouse delta increased Pguanidinium/PNa more than twofold and reduced PCs/PNa by 34% and PLi/PNa by 20%. The wild-type mouse receptor displayed a surprising interaction with the primary ammonium cations; relative permeability peaked at a chain length equal to four carbons. Analysis of the organic permeability ratios for the wild-type mouse receptor shows that (a) the diameter of the narrowest part of the pore is 8.4 A; (b) the mouse receptor departs significantly from size selectivity for monovalent organic cations; and (c) lowering the temperature reduces Pguanidinium/PNa by 38% and Pbutylammonium/PNa more than twofold. The results reinforce present views that positions -1' and 2' are the narrowest part of the pore and suggest that positions 6' and 10' align some permeant organic cations in the pore in an interaction similar to that with channel blocker, QX-222. PMID:1431803

Interannual tropical Pacific sea surface temperature anomalies teleconnection to Northern Hemisphere atmosphere in November

NASA Astrophysics Data System (ADS)

King, Martin P.; Herceg-Bulić, Ivana; Kucharski, Fred; Keenlyside, Noel

2018-03-01

We investigate the Northern Hemisphere atmospheric circulation anomalies associated to the sea surface temperature (SST) anomalies that are related to the eastern-Pacific and central-Pacific El Nino-Southern Oscillations in the late autumn (November). This research is motivated by the need for improving understanding of the autumn climate conditions which can impact on winter climate, as well as the relative lack of study on the boreal autumn climate processes compared to winter. Using reanalysis and SST datasets available from the late nineteenth century through the recent years, we found that there are two major atmospheric responses; one is a hemispheric-wide wave number-4 pattern, another has a more annular pattern. Both of these project on the East Atlantic pattern (southward-shifted North Atlantic Oscillation) in the Atlantic sector. Which of the patterns is active is suggested to depend on the background mean flow, with the annular anomaly active in the most recent decades, while the wave-4 pattern in the decades before. This switch is associated with a change of correlation sign in the North Pacific. We discuss the robustness of this finding. The ability of two atmospheric general circulation models (ICTP-AGCM and ECHAM-AGCM) to reproduce the teleconnections is also examined. Evidence provided shows that the wave-4 pattern and the East Atlantic pattern signals can be reproduced by the models, while the shift from this to an annular response for the recent years is not found conclusively.

Probing Lewis Acid-Base Interactions with Born-Oppenheimer Molecular Dynamics: The Electronic Absorption Spectrum of p-Nitroaniline in Supercritical CO2.

PubMed

Cabral, Benedito J Costa; Rivelino, Roberto; Coutinho, Kaline; Canuto, Sylvio

2015-07-02

The structure and dynamics of p-nitroaniline (PNA) in supercritical CO2 (scCO2) at T = 315 K and ρ = 0.81 g cm(-3) are investigated by carrying out Born-Oppenheimer molecular dynamics, and the electronic absorption spectrum in scCO2 is determined by time dependent density functional theory. The structure of the PNA-scCO2 solution illustrates the role played by Lewis acid-base (LA-LB) interactions. In comparison with isolated PNA, the ν(N-O) symmetric and asymmetric stretching modes of PNA in scCO2 are red-shifted by -17 and -29 cm(-1), respectively. The maximum of the charge transfer (CT) absorption band of PNA in scSCO2 is at 3.9 eV, and the predicted red-shift of the π → π* electronic transition relative to the isolated gas-phase PNA molecule reproduces the experimental value of -0.35 eV. An analysis of the relationship between geometry distortions and excitation energies of PNA in scCO2 shows that the π → π* CT transition is very sensitive to changes of the N-O bond distance, strongly indicating a correlation between vibrational and electronic solvatochromism driven by LA-LB interactions. Despite the importance of LA-LB interactions to explain the solvation of PNA in scCO2, the red-shift of the CT band is mainly determined by electrostatic interactions.

Midcontinental Native American population dynamics and late Holocene hydroclimate extremes

NASA Astrophysics Data System (ADS)

Bird, Broxton W.; Wilson, Jeremy J.; Gilhooly, William P., III; Steinman, Byron A.; Stamps, Lucas

2017-01-01

Climate’s influence on late Pre-Columbian (pre-1492 CE), maize-dependent Native American populations in the midcontinental United States (US) is poorly understood as regional paleoclimate records are sparse and/or provide conflicting perspectives. Here, we reconstruct regional changes in precipitation source and seasonality and local changes in warm-season duration and rainstorm events related to the Pacific North American pattern (PNA) using a 2100-year-long multi-proxy lake-sediment record from the midcontinental US. Wet midcontinental climate reflecting negative PNA-like conditions occurred during the Medieval Climate Anomaly (950-1250 CE) as Native American populations adopted intensive maize agriculture, facilitating population aggregation and the development of urban centers between 1000-1200 CE. Intensifying midcontinental socio-political instability and warfare between 1250-1350 CE corresponded with drier positive PNA-like conditions, culminating in the staggered abandonment of many major Native American river valley settlements and large urban centers between 1350-1450 CE during an especially severe warm-season drought. We hypothesize that this sustained drought interval rendered it difficult to support dense populations and large urban centers in the midcontinental US by destabilizing regional agricultural systems, thereby contributing to the host of socio-political factors that led to population reorganization and migration in the midcontinent and neighboring regions shortly before European contact.

Midcontinental Native American population dynamics and late Holocene hydroclimate extremes

PubMed Central

Bird, Broxton W.; Wilson, Jeremy J.; Gilhooly III, William P.; Steinman, Byron A.; Stamps, Lucas

2017-01-01

Climate’s influence on late Pre-Columbian (pre-1492 CE), maize-dependent Native American populations in the midcontinental United States (US) is poorly understood as regional paleoclimate records are sparse and/or provide conflicting perspectives. Here, we reconstruct regional changes in precipitation source and seasonality and local changes in warm-season duration and rainstorm events related to the Pacific North American pattern (PNA) using a 2100-year-long multi-proxy lake-sediment record from the midcontinental US. Wet midcontinental climate reflecting negative PNA-like conditions occurred during the Medieval Climate Anomaly (950–1250 CE) as Native American populations adopted intensive maize agriculture, facilitating population aggregation and the development of urban centers between 1000–1200 CE. Intensifying midcontinental socio-political instability and warfare between 1250–1350 CE corresponded with drier positive PNA-like conditions, culminating in the staggered abandonment of many major Native American river valley settlements and large urban centers between 1350–1450 CE during an especially severe warm-season drought. We hypothesize that this sustained drought interval rendered it difficult to support dense populations and large urban centers in the midcontinental US by destabilizing regional agricultural systems, thereby contributing to the host of socio-political factors that led to population reorganization and migration in the midcontinent and neighboring regions shortly before European contact. PMID:28139698

Defining Subpopulations of Arcuate Nucleus GABA Neurons in Male, Female, and Prenatally Androgenized Female Mice.

PubMed

Marshall, Christopher J; Desroziers, Elodie; McLennan, Timothy; Campbell, Rebecca E

2017-01-01

Arcuate nucleus (ARN) γ-aminobutyric acid (GABA) neurons are implicated in many critical homeostatic mechanisms, from food intake to fertility. To determine the functional relevance of ARN GABA neurons, it is essential to define the neurotransmitters co-expressed with and potentially co-released from ARN GABA neurons. The present study investigated the expression of markers of specific signaling molecules by ARN GABA neurons in brain sections from male, female, and, in some cases, prenatally androgen-treated (PNA) female, vesicular GABA transporter (VGaT)-ires-Cre/tdTomato reporter mice. Immunofluorescence for kisspeptin, β-endorphin, neuropeptide Y (NPY), tyrosine hydroxylase (TH) and neuronal nitric oxide synthase (nNOS) was detected by confocal microscopy, and co-localization with tdTomato VGaT reporter expression throughout the ARN was quantified. GABA neurons rarely co-localized with kisspeptin (<2%) or β-endorphin (<1%), and only a small proportion of kisspeptin (∼10%) or β-endorphin (∼3%) neurons co-localized with VGaT in male and female mice. In contrast, one-third of ARN GABA neurons co-localized with NPY, and nearly all NPY neurons (>95%) co-localized with VGaT across groups. Both TH and nNOS labeling was co-localized with ∼10% of ARN GABA neurons. The proportion of TH neurons co-localized with VGaT was significantly greater in males than either control or PNA females, and the proportion of nNOS neurons co-localizing VGaT was higher in control and PNA females compared with males. These data highlight NPY as a significant subpopulation of ARN GABA neurons, demonstrate no significant impact of PNA on signal co-expression, and, for the first time, show sexually dimorphic co-expression patterns of TH and nNOS with ARN GABA neurons. © 2016 S. Karger AG, Basel.

Information transfer from peptide nucleic acids to RNA by template-directed syntheses

NASA Technical Reports Server (NTRS)

Schmidt, J. G.; Nielsen, P. E.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

1997-01-01

Peptide nucleic acids (PNAs) are uncharged analogs of DNA and RNA in which the ribose-phosphate backbone is substituted by a backbone held together by amide bonds. PNAs are interesting as models of alternative genetic systems because they form potentially informational base paired helical structures. A PNA C10 oligomer has been shown to act as template for efficient formation of oligoguanylates from activated guanosine ribonucleotides. In a previous paper we used heterosequences of DNA as templates in sequence-dependent polymerization of PNA dimers. In this paper we show that information can be transferred from PNA to RNA. We describe the reactions of activated mononucleotides on heterosequences of PNA. Adenylic, cytidylic and guanylic acids were incorporated into the products opposite their complement on PNA, although less efficiently than on DNA templates.

Predicting Tree Mortality Die-off Events Associated with Hotter Drought and Assessing Their Global Consequences via Ecoclimate Teleconnections.

NASA Astrophysics Data System (ADS)

Breshears, D. D.; Allen, C. D.; McDowell, N. G.; Adams, H. D.; Barnes, M.; Barron-Gafford, G.; Bradford, J. B.; Cobb, N.; Field, J. P.; Froend, R.; Fontaine, J. B.; Garcia, E.; Hardy, G. E. S. J.; Huxman, T. E.; Kala, J.; Lague, M. M.; Martinez-Yrizar, A.; Matusick, G.; Minor, D. M.; Moore, D. J.; Ng, M.; Ruthrof, K. X.; Saleska, S. R.; Stark, S. C.; Swann, A. L. S.; Villegas, J. C.; Williams, A. P.; Zou, C.

2017-12-01

Evidence that tree mortality is increasingly likely occur in extensive die-off events across the terrestrial biosphere continues to mount. The consequences of such extensive mortality events are potentially profound, not only for the locations where die-off events occur, but also for other locations that could be impacted via ecoclimate teleconnections, whereby the land surface changes associated with die-off in one location could alter atmospheric circulation patterns and affect vegetation elsewhere. Here, we (1) recap the background of tree mortality as an emerging environmental issue, (2) highlight recent advances that could help us improve predictions of the vulnerability to tree mortality, including the underlying importance of hydraulic failure, the potential to develop climatic envelopes specific to tree mortality events, and consideration of the role of heat waves; and (3) initial bounding simulations that indicate the potential for tree die-off events in different locations to alter ecoclimate teleconnections. As we move toward globally coordinated carbon accounting and management, the high vulnerability to tree die-off events and the potential for such events to affect vegetation elsewhere will both need to be accounted for.

Stationarity of the Tropical Pacific Teleconnection to North America in CMIP5 PMIP3 Model Simulations

NASA Technical Reports Server (NTRS)

Coats, Sloan; Smerdon, Jason E.; Cook, Benjamin I.; Seager, Richard

2013-01-01

The temporal stationarity of the teleconnection between the tropical Pacific Ocean and North America (NA) is analyzed in atmosphere-only, and coupled last-millennium, historical, and control runs from the Coupled Model Intercomparison Project Phase 5 data archive. The teleconnection, defined as the correlation between December-January-February (DJF) tropical Pacific sea surface temperatures (SSTs) and DJF 200 mb geopotential height, is found to be nonstationary on multidecadal timescales. There are significant changes in the spatial features of the teleconnection over NA in continuous 56-year segments of the last millennium and control simulations. Analysis of atmosphere-only simulations forced with observed SSTs indicates that atmospheric noise cannot account for the temporal variability of the teleconnection, which instead is likely explained by the strength of, and multidecadal changes in, tropical Pacific Ocean variability. These results have implications for teleconnection-based analyses of model fidelity in simulating precipitation, as well as any reconstruction and forecasting efforts that assume stationarity of the observed teleconnection.

Teleconnection between sea ice in the Barents Sea in June and the Silk Road, Pacific-Japan and East Asian rainfall patterns in August

NASA Astrophysics Data System (ADS)

He, Shengping; Gao, Yongqi; Furevik, Tore; Wang, Huijun; Li, Fei

2018-01-01

In contrast to previous studies that have tended to focus on the influence of the total Arctic sea-ice cover on the East Asian summer tripole rainfall pattern, the present study identifies the Barents Sea as the key region where the June sea-ice variability exerts the most significant impacts on the East Asian August tripole rainfall pattern, and explores the teleconnection mechanisms involved. The results reveal that a reduction in June sea ice excites anomalous upward air motion due to strong near-surface thermal forcing, which further triggers a meridional overturning wave-like pattern extending to midlatitudes. Anomalous downward motion therefore forms over the Caspian Sea, which in turn induces zonally oriented overturning circulation along the subtropical jet stream, exhibiting the east-west Rossby wave train known as the Silk Road pattern. It is suggested that the Bonin high, a subtropical anticyclone predominant near South Korea, shows a significant anomaly due to the eastward extension of the Silk Road pattern to East Asia. As a possible descending branch of the Hadley cell, the Bonin high anomaly ultimately triggers a meridional overturning, establishing the Pacific-Japan pattern. This in turn induces an anomalous anticyclone and cyclone pair over East Asia, and a tripole vertical convection anomaly meridionally oriented over East Asia. Consequently, a tripole rainfall anomaly pattern is observed over East Asia. Results from numerical experiments using version 5 of the Community Atmosphere Model support the interpretation of this chain of events.

Teleconnection between Sea Ice in the Barents Sea in June and the Silk Road, Pacific-Japan and East Asian Rainfall Patterns in August

NASA Astrophysics Data System (ADS)

He, S.; Gao, Y.; Furevik, T.; Huijun, W.; Li, F.

2017-12-01

In contrast to previous studies that have tended to focus on the influence of the total Arctic sea-ice cover on the East Asian summer tripole rainfall pattern, the present study identifies the Barents Sea as the key region where the June sea-ice variability exerts the most significant impacts on the East Asian August tripole rainfall pattern, and explores the teleconnection mechanisms involved. The results reveal that a reduction in June sea ice excites anomalous upward air motion due to strong near-surface thermal forcing, which further triggers a meridional overturning wave-like pattern extending to midlatitudes. Anomalous downward motion therefore forms over the Caspian Sea, which in turn induces zonally oriented overturning circulation along the subtropical jet stream, exhibiting the east-west Rossby wave train known as the Silk Road pattern. It is suggested that the Bonin high, a subtropical anticyclone predominant near South Korea, shows a significant anomaly due to the eastward extension of the Silk Road pattern to East Asia. As a possible descending branch of the Hadley cell, the Bonin high anomaly ultimately triggers a meridional overturning, establishing the Pacific-Japan pattern. This in turn induces an anomalous anticyclone and cyclone pair over East Asia, and a tripole vertical convection anomaly meridionally oriented over East Asia. Consequently, a tripole rainfall anomaly pattern is observed over East Asia. Results from numerical experiments using version 5 of the Community Atmosphere Model support the interpretation of this chain of events.

Analysis of the 2015-16 El Niño Event Using NASA's GEOS Data Assimilation System

NASA Astrophysics Data System (ADS)

Pawson, S.; Lim, Y. K.; Kovach, R. M.; Vernieres, G.

2016-12-01

The strong El Niño event that occurred in 2015/2016 is analyzed using atmospheric and oceanic analyses produced using the Goddard Earth Observing System (GEOS) systems. A theme of the work is to compare and contrast this event with two other strong El Niños, in 1982/1983 and 1997/1998, that are included in the satellite-data era of the MERRA and MERRA-2 reanalyses produced using the GEOS system. Distribution of the maximum anomalies of tropical sea-surface temperature (SST), precipitation, Walker circulation, and cloud fraction indicate that 2015/2016 is a Central Pacific (CP) El Niño. The event had an early onset compared to the 1997/1998 El Niño, with extremely strong warming and precipitation over the Central Pacific, and was the strongest in terms of central Pacific SST anomalies. The large region of warm temperature anomalies over most of the Pacific and Indian Ocean in the 2015-2016 event were due to the accumulative impacts of the El Niño event along with a positive phase of the Pacific Decadal Oscillation and a decadal warming trend over the western Pacific, Maritime Continent, and Indian Ocean. The relatively weak development of the 2015/2016 El Niño event over the Eastern Pacific was likely due to weaker westerly wind bursts and Madden-Julian Oscillation during spring, which in 1997/1998 served to drive the warm anomalies further East towards South America, making that event the strongest Eastern Pacific El Niño (in the recent data record). This is reflected in the 2015/2016 event having a shallower thermocline over the Eastern Pacific, with a weaker zonal gradient of sub-surface water temperatures along the equatorial Pacific. The major extra-tropical teleconnections associated with the El Niño in 2015/2016 are at least comparable to those in the 1982/1983 and 1997/1998 El Niño events. Specifically, the Pacific North American (PNA) teleconnection in 2015/2016 is the strongest of these three El Niño events, leading to larger extra-tropical anomalies of geopotential height, temperature, and precipitation over North America.

Strand-invading linear probe combined with unmodified PNA.

PubMed

Asanuma, Hiroyuki; Niwa, Rie; Akahane, Mariko; Murayama, Keiji; Kashida, Hiromu; Kamiya, Yukiko

2016-09-15

Efficient strand invasion by a linear probe to fluorescently label double-stranded DNA has been implemented by employing a probe and unmodified PNA. As a fluorophore, we utilized ethynylperylene. Multiple ethynylperylene residues were incorporated into the DNA probe via a d-threoninol scaffold. The ethynylperylene did not significantly disrupt hybridization with complementary DNA. The linear probe self-quenched in the absence of target DNA and did not hybridize with PNA. A gel-shift assay revealed that linear probe and PNA combination invaded the central region of double-stranded DNA upon heat-shock treatment to form a double duplex. To further suppress the background emission and increase the stability of the probe/DNA duplex, a probe containing anthraquinones as well as ethynylperylene was synthesized. This probe and PNA invader pair detected an internal sequence in a double-stranded DNA with high sensitivity when heat shock treatment was used. The probe and PNA pair was able to invade at the terminus of a long double-stranded DNA at 40°C at 100mM NaCl concentration. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Study of Subseasonal Predictability of the Atmospheric Circulation Low-frequency Modes based on SL-AV forecasts

NASA Astrophysics Data System (ADS)

Kruglova, Ekaterina; Kulikova, Irina; Khan, Valentina; Tischenko, Vladimir

2017-04-01

The subseasonal predictability of low-frequency modes and the atmospheric circulation regimes is investigated based on the using of outputs from global Semi-Lagrangian (SL-AV) model of the Hydrometcentre of Russia and Institute of Numerical Mathematics of Russian Academy of Science. Teleconnection indices (AO, WA, EA, NAO, EU, WP, PNA) are used as the quantitative characteristics of low-frequency variability to identify zonal and meridional flow regimes with focus on control distribution of high impact weather patterns in the Northern Eurasia. The predictability of weekly and monthly averaged indices is estimated by the methods of diagnostic verification of forecast and reanalysis data covering the hindcast period, and also with the use of the recommended WMO quantitative criteria. Characteristics of the low frequency variability have been discussed. Particularly, it is revealed that the meridional flow regimes are reproduced by SL-AV for summer season better comparing to winter period. It is shown that the model's deterministic forecast (ensemble mean) skill at week 1 (days 1-7) is noticeably better than that of climatic forecasts. The decrease of skill scores at week 2 (days 8-14) and week 3( days 15-21) is explained by deficiencies in the modeling system and inaccurate initial conditions. It was noticed the slightly improvement of the skill of model at week 4 (days 22-28), when the condition of atmosphere is more determined by the flow of energy from the outside. The reliability of forecasts of monthly (days 1-30) averaged indices is comparable to that at week 1 (days 1-7). Numerical experiments demonstrated that the forecast accuracy can be improved (thus the limit of practical predictability can be extended) through the using of probabilistic approach based on ensemble forecasts. It is shown that the quality of forecasts of the regimes of circulation like blocking is higher, than that of zonal flow.

Anionic magnetite nanoparticle conjugated with pyrrolidinyl peptide nucleic acid for DNA base discrimination

NASA Astrophysics Data System (ADS)

Khadsai, Sudarat; Rutnakornpituk, Boonjira; Vilaivan, Tirayut; Nakkuntod, Maliwan; Rutnakornpituk, Metha

2016-09-01

Magnetite nanoparticles (MNPs) were surface modified with anionic poly( N-acryloyl glycine) (PNAG) and streptavidin for specific interaction with biotin-conjugated pyrrolidinyl peptide nucleic acid (PNA). Hydrodynamic size ( D h) of PNAG-grafted MNPs varied from 334 to 496 nm depending on the loading ratio of the MNP to NAG in the reaction. UV-visible and fluorescence spectrophotometries were used to confirm the successful immobilization of streptavidin and PNA on the MNPs. About 291 pmol of the PNA/mg MNP was immobilized on the particle surface. The PNA-functionalized MNPs were effectively used as solid supports to differentiate between fully complementary and non-complementary/single-base mismatch DNA using the PNA probe. These novel anionic MNPs can be efficiently applicable for use as a magnetically guidable support for DNA base discrimination.

North Atlantic teleconnection patterns signature on sea level from satellite altimetry

NASA Astrophysics Data System (ADS)

Iglesias, Isabel; Lázaro, Clara; Joana Fernandes, M.; Bastos, Luísa

2015-04-01

Presently, satellite altimetry record is long enough to appropriately study inter-annual signals in sea level anomaly and ocean surface circulation, allowing the association of teleconnection patterns of low-frequency variability with the response of sea level. The variability of the Atlantic Ocean at basin-scale is known to be complex in space and time, with the dominant mode occurring on annual timescales. However, interannual and decadal variability have already been documented in sea surface temperature. Both modes are believed to be linked and are known to influence sea level along coastal regions. The analysis of the sea level multiannual variability is thus essential to understand the present climate and its long-term variability. While in the open-ocean sea level anomaly from satellite altimetry currently possesses centimetre-level accuracy, satellite altimetry measurements become invalid or of lower accuracy along the coast due to the invalidity of the wet tropospheric correction (WTC) derived from on-board microwave radiometers. In order to adequately analyse long-term changes in sea level in the coastal regions, satellite altimetry measurements can be recovered by using an improved WTC computed from recent algorithms that combine wet path delays from all available observations (remote sensing scanning imaging radiometers, GNSS stations, microwave radiometers on-board satellite altimetry missions and numerical weather models). In this study, a 20-year (1993-2013) time series of multi-mission satellite altimetry (TOPEX/Poseidon, Jason-1, OSTM/Jason-2, ERS-1/2, ENVISAT, CryoSat-2 and SARAL), are used to characterize the North Atlantic (NA) long-term variability on sea level at basin-scale and analyse its response to several atmospheric teleconnections known to operate on the NA. The altimetry record was generated using an improved coastal WTC computed from either the GNSS-derived path Delay or the Data Combination methodologies developed by University of Porto (Fernandes et al., 2010; Fernandes et al., 2013). Regular 0.25°x0.25° latitude-longitude grids were generated at a 10-day interval for the NA Ocean (60°W-5°W, 5°N-60°N) using optimal interpolation with a realistic space-time correlation function (Lázaro et al., 2013). These grids are used to inspect the response of sea level anomalies to several teleconnection patterns as well as the NA variability on annual and longer timescales. The teleconnection patterns selected are the ones that have influence on the NA basin: North Atlantic Oscillation, East Atlantic pattern, East Atlantic/Western Russia pattern, Scandinavia pattern, Western Mediterranean Oscillation index, El Niño Southern Oscillation, Tropical North Atlantic Index, and Atlantic Multidecadal Oscillation. Acknowledgments: RAIA tec (0688-RAIATEC-1-P) project. The RAIA Coastal Observatory has been funded by the Programa Operativo de Cooperación Transfronteriza España-Portugal (POCTEP 2007-2013). References: Fernandes M.J., C. Lázaro, A.L. Nunes, N. Pires, L. Bastos, V.B. Mendes (2010). GNSS-derived Path Delay: an approach to compute the wet tropospheric correction for coastal altimetry. IEEE Geosci. Rem. Sens Lett., Vol. 7, NO. 3, 596 - 600, doi: 10.1109/LGRS.2010.2042425. Lázaro, C., M. J. Juliano, M. J. Fernandes (2013): Semi-automatic determination of the Azores Current axis using satellite altimetry: application to the study of the current variability during 1995-2006. Advances in Space Research, Vol. 51(11), pp. 2155-2170, doi:10.1016/j.asr.2012.12.021. Fernandes, M. J., A.L. Nunes, C. Lázaro (2013). Analysis and Inter-Calibration of Wet Path Delay Datasets to Compute the Wet Tropospheric Correction for CryoSat-2 over Ocean. Remote Sensing, 5, 4977-5005.

Met UM Upper-tropospheric summer jet teleconnections: A model assessment

NASA Astrophysics Data System (ADS)

Joao Carvalho, Maria; Rodriguez, Jose; Milton, Sean

2017-04-01

The upper tropospheric jet stream has been documented to act as a waveguide (Hoskins and Ambrizzi, 1993) and supporting quasi-stationary Rossby waves (Schubert et al. 2011). These have been associated with remote effects in surface level weather such as rainfall anomalies in the East Asian Summer Monsoon as well as extreme temperature events. The goal of this work was to analyse the intraseasonal to interannual upper level boreal summer jet variability and its coupling with low level atmospheric dynamics within the Met Office Unified Model using climate runs. Using the Wallace and Gutzler (1981) proposed approach to find teleconnection patterns on the 200 hPa level wind, lead-lag correlation and Empirical Orthogonal Function analysis on the upper-level jet and relating the results with surface weather variables as well as dynamical variables, it was found that the model presents too strong jet variability, particularly in the tropical region and. In addition, the model presents high teleconnectivity hotspots with higher importance in areas such as the Mediterranean and Caspian Sea which are important source areas for Rossby Waves. Further to this, the model was found to produce an area of teleconnectivity between the tropical Atlantic and western Africa which is not observed in the reanalysis but coexists with long lasting precipitation biases. As comparison for the model results, ERA-Interim circulation and wind data and the TRMM precipitation dataset were used. In order to assess the relative importance of relevant model parameters in the biases and process errors, work is currently underway using perturbed model parameter ensembles.

Stratospheric role in interdecadal changes of El Niño impacts over Europe

NASA Astrophysics Data System (ADS)

Ayarzagüena, B.; López-Parages, J.; Iza, M.; Calvo, N.; Rodríguez-Fonseca, B.

2018-04-01

The European precipitation response to El Niño (EN) has been found to present interdecadal changes, with alternated periods of important or negligible EN impact in late winter. These periods are associated with opposite phases of multi-decadal sea surface temperature (SST) variability, which modifies the tropospheric background and EN teleconnections. In addition, other studies have shown how SST anomalies in the equatorial Pacific, and in particular, the location of the largest anomalous SST, modulate the stratospheric response to EN. Nevertheless, the role of the stratosphere on the stationarity of EN response has not been investigated in detail so far. Using reanalysis data, we present a comprehensive study of EN teleconnections to Europe including the role of the ocean background and the stratosphere in the stationarity of the signal. The results reveal multidecadal variability in the location of EN-related SST anomalies that determines different teleconnections. In periods with relevant precipitation signal over Europe, the EN SST pattern resembles Eastern Pacific EN and the stratospheric pathway plays a key role in transmitting the signal to Europe in February, together with two tropospheric wavetrains that transmit the signal in February and April. Conversely, the stratospheric pathway is not detected in periods with a weak EN impact on European precipitation, corresponding to EN-related SST anomalies primarily located over the central Pacific. SST mean state and its associated atmospheric background control the location of EN-related SST anomalies in different periods and modulate the establishment of the aforementioned stratospheric pathway of EN teleconnection to Europe too.

La Niña diversity and Northwest Indian Ocean Rim teleconnections

USGS Publications Warehouse

Hoell, Andrew; Funk, Christopher C.; Barlow, Mathew

2014-01-01

The differences in tropical Pacific sea surface temperature (SST) expressions of El Niño-Southern Oscillation (ENSO) events of the same phase have been linked with different global atmospheric circulation patterns. This study examines the dynamical forcing of precipitation during October–December (OND) and March–May (MAM) over East Africa and during December–March (DJFM) over Central-Southwest Asia for 1950–2010 associated with four tropical Pacific SST patterns characteristic of La Niña events, the cold phase of ENSO. The self-organizing map method along with a statistical distinguishability test was used to isolate La Niña events, and seasonal precipitation forcing was investigated in terms of the tropical overturning circulation and thermodynamic and moisture budgets. Recent La Niña events with strong opposing SST anomalies between the central and western Pacific Ocean (phases 3 and 4), force the strongest global circulation modifications and drought over the Northwest Indian Ocean Rim. Over East Africa during MAM and OND, subsidence is forced by an enhanced tropical overturning circulation and precipitation reductions are exacerbated by increases in moisture flux divergence. Over Central-Southwest Asia during DJFM, the thermodynamic forcing of subsidence is primarily responsible for precipitation reductions, with moisture flux divergence acting as a secondary mechanism to reduce precipitation. Eastern Pacific La Niña events in the absence of west Pacific SST anomalies (phases 1 and 2), are associated with weaker global teleconnections, particularly over the Indian Ocean Rim. The weak regional teleconnections result in statistically insignificant precipitation modifications over East Africa and Central-Southwest Asia.

Droughts in Amazonia: Spatiotemporal Variability, Teleconnections, and Seasonal Predictions

NASA Astrophysics Data System (ADS)

Lima, Carlos H. R.; AghaKouchak, Amir

2017-12-01

Most Amazonia drought studies have focused on rainfall deficits and their impact on river discharges, while the analysis of other important driver variables, such as temperature and soil moisture, has attracted less attention. Here we try to better understand the spatiotemporal dynamics of Amazonia droughts and associated climate teleconnections as characterized by the Palmer Drought Severity Index (PDSI), which integrates information from rainfall deficit, temperature anomalies, and soil moisture capacity. The results reveal that Amazonia droughts are most related to one dominant pattern across the entire region, followed by two seesaw kind of patterns: north-south and east-west. The main two modes are correlated with sea surface temperature (SST) anomalies in the tropical Pacific and Atlantic oceans. The teleconnections associated with global SST are then used to build a seasonal forecast model for PDSI over Amazonia based on predictors obtained from a sparse canonical correlation analysis approach. A unique feature of the presented drought prediction method is using only a few number of predictors to avoid excessive noise in the predictor space. Cross-validated results show correlations between observed and predicted spatial average PDSI up to 0.60 and 0.45 for lead times of 5 and 9 months, respectively. To the best of our knowledge, this is the first study in the region that, based on cross-validation results, leads to appreciable forecast skills for lead times beyond 4 months. This is a step forward in better understanding the dynamics of Amazonia droughts and improving risk assessment and management, through improved drought forecasting.

Comparative biodistributions and dosimetry of [¹⁷⁷Lu]DOTA-anti-bcl-2-PNA-Tyr³-octreotate and [¹⁷⁷Lu]DOTA-Tyr³-octreotate in a mouse model of B-cell lymphoma/leukemia.

PubMed

Balkin, Ethan R; Liu, Dijie; Jia, Fang; Ruthengael, Varyanna C; Shaffer, Suzanne M; Miller, William H; Lewis, Michael R

2014-01-01

The B-cell lymphoma/leukemia-2 (bcl-2) proto-oncogene in non-Hodgkin's lymphoma (NHL) is a dominant inhibitor of apoptosis. We developed a (177)Lu-labeled bcl-2 antisense peptide nucleic acid (PNA)-peptide conjugate designed for dual modality NHL therapy, consisting of a radiopharmaceutical capable of simultaneously down-regulating apoptotic resistance and delivering cytotoxic internally emitted radiation. DOTA-anti-bcl-2-Tyr(3)-octreotate was synthesized, labeled with (177)Lu, and purified using RP-HPLC. The PNA-peptide conjugate was evaluated in Mec-1 NHL-bearing mice and compared to [(177)Lu]DOTA-Tyr(3)-octreotate in biodistribution and excretion studies. These data were then used to generate in vivo dosimetry models. The PNA-peptide conjugate was readily prepared and radiolabeled in high yield and radiochemical purity. An in vivo blocking study determined that administration of 50 μg of non-radioactive PNA-peptide was the optimal mass for maximum delivery to the tumor. Based on that result, a dosing regimen of (177)Lu-PNA-peptide, for radiologic effect, followed by the optimal mass of non-radioactive compound, for antisense effect, was designed. Using that dosing regimen, biodistribution of the PNA-peptide showed uptake in the tumor with minimal washout over a 4-day period. Uptakes in receptor-positive normal organs were low and displayed nearly complete washout by 24h. Dosimetry models showed that the tumor absorbed dose of the PNA-peptide conjugate was approximately twice that of the peptide-only conjugate. Biodistribution data showed specific tumor targeting of the (177)Lu-labeled PNA-peptide compound with minimal receptor-positive normal tissue uptake when compared to [(177)Lu]DOTA-Tyr(3)-octreotate. In vivo dosimetry models predicted a more favorable tumor absorbed dose from [(177)Lu]DOTA-anti-bcl-2-Tyr(3)-octreotate. © 2013.

Studies on the oligosaccharide heterogeneity of the isoelectric forms of the lower molecular weight acid phosphatase of frog liver.

PubMed

Kubicz, A; Szalewicz, A; Chrambach, A

1991-01-01

1. The lower molecular weight, heterogeneous acid phosphatase (AcPase) from the frog liver (Rana esculenta) containing AcPase I, II, III and IV was separated into enzymatically active components by isoelectric focusing in an immobilized pH gradient. 2. The blotted enzyme bands were characterized by their different binding patterns obtained with the lectins concanavalin A, wheat germ agglutinin (WGA), Lens culinaris hemagglutinin (LcH) and peanut agglutinin (PNA). 3. In situ neuraminidase treatment reduced the staining intensity of some WGA-bands and increased that of PNA-bands. 4. The finding that AcPases I, II, III and IV differ in their carbohydrate chain composition, together with previous results showing different bioactivities of AcPases III and IV, indicates a correlation between the glycosylation state of enzyme forms and their physiological action.

Identification of canine T lymphocytes by membrane receptor to peanut agglutinin: T-lymphocyte identification in dogs with lupus-like syndrome.

PubMed

Rigal, D; Bendali-Ahcène, S; Monier, J C; Mohana, K; Fournel, C

1983-09-01

Canine T lymphocytes were detected, using fluorescent peanut agglutinin (PNA) as a marker. Using a fluorescent technique and cytofluorometry, 70 +/- 11% and 72.4%, respectively, of peripheral blood lymphocytes were bound to PNA. Of thymocytes, 97 +/- 4.5% were detected by fluorescent PNA, but less than 1% were detected for lymphocytes from bone marrow. The T-lymphocyte depletion and enrichment indicated that PNA was bound to lymphocytes recognized by anti-T-lymphocyte heterologous serum. A T-lymphocyte deficiency was detected among 8 dogs with a lupus-like syndrome.

Peptide nucleic acid probe for protein affinity purification based on biotin-streptavidin interaction and peptide nucleic acid strand hybridization.

PubMed

Tse, Jenny; Wang, Yuanyuan; Zengeya, Thomas; Rozners, Eriks; Tan-Wilson, Anna

2015-02-01

We describe a new method for protein affinity purification that capitalizes on the high affinity of streptavidin for biotin but does not require dissociation of the biotin-streptavidin complex for protein retrieval. Conventional reagents place both the selectively reacting group (the "warhead") and the biotin on the same molecule. We place the warhead and the biotin on separate molecules, each linked to a short strand of peptide nucleic acid (PNA), synthetic polymers that use the same bases as DNA but attached to a backbone that is resistant to attack by proteases and nucleases. As in DNA, PNA strands with complementary base sequences hybridize. In conditions that favor PNA duplex formation, the warhead strand (carrying the tagged protein) and the biotin strand form a complex that is held onto immobilized streptavidin. As in DNA, the PNA duplex dissociates at moderately elevated temperature; therefore, retrieval of the tagged protein is accomplished by a brief exposure to heat. Using iodoacetate as the warhead, 8-base PNA strands, biotin, and streptavidin-coated magnetic beads, we demonstrate retrieval of the cysteine protease papain. We were also able to use our iodoacetyl-PNA:PNA-biotin probe for retrieval and identification of a thiol reductase and a glutathione transferase from soybean seedling cotyledons. Copyright © 2014 Elsevier Inc. All rights reserved.

Recognition of Double Stranded RNA by Guanidine-Modified Peptide Nucleic Acids (GPNA)

PubMed Central

Gupta, Pankaj; Muse, Oluwatoyosi; Rozners, Eriks

2011-01-01

Double helical RNA has become an attractive target for molecular recognition because many non-coding RNAs play important roles in control of gene expression. Recently, we discovered that short peptide nucleic acids (PNA) bind strongly and sequence selectively to a homopurine tract of double helical RNA via triple helix formation. Herein we tested if the molecular recognition of RNA can be enhanced by α-guanidine modification of PNA. Our study was motivated by the discovery of Ly and co-workers that the guanidine modification greatly enhances the cellular delivery of PNA. Isothermal titration calorimetry showed that the guanidine-modified PNA (GPNA) had reduced affinity and sequence selectivity for triple helical recognition of RNA. The data suggested that in contrast to unmodified PNA, which formed a 1:1 PNA-RNA triple helix, GPNA preferred a 2:1 GPNA-RNA triplex-invasion complex. Nevertheless, promising results were obtained for recognition of biologically relevant double helical RNA. Consistent with enhanced strand invasion ability, GPNA derived from D-arginine recognized the transactivation response element (TAR) of HIV-1 with high affinity and sequence selectivity, presumably via Watson-Crick duplex formation. On the other hand, strong and sequence selective triple helices were formed by unmodified and nucelobase-modified PNAs and the purine rich strand of bacterial A-site. These results suggest that appropriate chemical modifications of PNA may enhance molecular recognition of complex non-coding RNAs. PMID:22146072

Prenatal androgenization of female mice programs an increase in firing activity of gonadotropin-releasing hormone (GnRH) neurons that is reversed by metformin treatment in adulthood.

PubMed

Roland, Alison V; Moenter, Suzanne M

2011-02-01

Prenatal androgenization (PNA) of female mice with dihydrotestosterone programs reproductive dysfunction in adulthood, characterized by elevated luteinizing hormone levels, irregular estrous cycles, and central abnormalities. Here, we evaluated activity of GnRH neurons from PNA mice and the effects of in vivo treatment with metformin, an activator of AMP-activated protein kinase (AMPK) that is commonly used to treat the fertility disorder polycystic ovary syndrome. Estrous cycles were monitored in PNA and control mice before and after metformin administration. Before metformin, cycles were longer in PNA mice and percent time in estrus lower; metformin normalized cycles in PNA mice. Extracellular recordings were used to monitor GnRH neuron firing activity in brain slices from diestrous mice. Firing rate was higher and quiescence lower in GnRH neurons from PNA mice, demonstrating increased GnRH neuron activity. Metformin treatment of PNA mice restored firing activity and LH to control levels. To assess whether AMPK activation contributed to the metformin-induced reduction in GnRH neuron activity, the AMPK antagonist compound C was acutely applied to cells. Compound C stimulated cells from metformin-treated, but not untreated, mice, suggesting that AMPK was activated in GnRH neurons, or afferent neurons, in the former group. GnRH neurons from metformin-treated mice also showed a reduced inhibitory response to low glucose. These studies indicate that PNA causes enhanced firing activity of GnRH neurons and elevated LH that are reversible by metformin, raising the possibility that central AMPK activation by metformin may play a role in its restoration of reproductive cycles in polycystic ovary syndrome.

Forecasting of Seasonal Rainfall using ENSO and IOD teleconnection with Classification Models

NASA Astrophysics Data System (ADS)

De Silva, T.; Hornberger, G. M.

2017-12-01

Seasonal to annual forecasts of precipitation patterns are very important for water infrastructure management. In particular, such forecasts can be used to inform decisions about the operation of multipurpose reservoir systems in the face of changing climate conditions. Success in making useful forecasts often is achieved by considering climate teleconnections such as the El-Nino-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD) as related to sea surface temperature variations. We present an analysis to explore the utility of using rainfall relationships in Sri Lanka with ENSO and IOD to predict rainfall to the Mahaweli, river basin. Forecasting of rainfall as classes - above normal, normal, and below normal - can be useful for water resource management decision making. Quadratic discrimination analysis (QDA) and random forest models are used to identify the patterns of rainfall classes with respect to ENSO and IOD indices. These models can be used to forecast the likelihood of areal rainfall anomalies using predicted climate indices. Results can be used for decisions regarding allocation of water for agriculture and electricity generation within the Mahaweli project of Sri Lanka.

Investigating the Relationship between Ocean Surface Currents and Seasonal Precipitation in the Western United States

NASA Astrophysics Data System (ADS)

Chiang, F.; AghaKouchak, A.

2017-12-01

While many studies have explored the predictive capabilities of teleconnections associated with North American climate, currently established teleconnections offer limited predictability for rainfall in the Western United States. A recent example was the 2015-16 California drought in which a strong ENSO signal did not lead to above average precipitation as was expected. From an exploration of climate and ocean variables available from satellite data, we hypothesize that ocean currents can provide additional information to explain precipitation variability and improve seasonal predictability on the West Coast. Since ocean currents are influenced by surface wind and temperatures, characterizing connections between currents and precipitation patterns has the potential to further our understanding of coastal weather patterns. For the study, we generated gridded point correlation maps to identify ocean areas with high correlation to precipitation time series corresponding to climate regions in the West Coast region. We also used other statistical measures to evaluate ocean `hot spot' regions with significant correlation to West Coast precipitation. Preliminary results show that strong correlations can be found in the tropical regions of the globe.

Hybrid DNA i-motif: Aminoethylprolyl-PNA (pC5) enhance the stability of DNA (dC5) i-motif structure.

PubMed

Gade, Chandrasekhar Reddy; Sharma, Nagendra K

2017-12-15

This report describes the synthesis of C-rich sequence, cytosine pentamer, of aep-PNA and its biophysical studies for the formation of hybrid DNA:aep-PNAi-motif structure with DNA cytosine pentamer (dC 5 ) under acidic pH conditions. Herein, the CD/UV/NMR/ESI-Mass studies strongly support the formation of stable hybrid DNA i-motif structure with aep-PNA even near acidic conditions. Hence aep-PNA C-rich sequence cytosine could be considered as potential DNA i-motif stabilizing agents in vivo conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Focus on PNA Flexibility and RNA Binding using Molecular Dynamics and Metadynamics

NASA Astrophysics Data System (ADS)

Verona, Massimiliano Donato; Verdolino, Vincenzo; Palazzesi, Ferruccio; Corradini, Roberto

2017-02-01

Peptide Nucleic Acids (PNAs) can efficiently target DNA or RNA acting as chemical tools for gene regulation. Their backbone modification and functionalization is often used to increase the affinity for a particular sequence improving selectivity. The understanding of the trading forces that lead the single strand PNA to bind the DNA or RNA sequence is preparatory for any further rational design, but a clear and unique description of this process is still not complete. In this paper we report further insights into this subject, by a computational investigation aiming at the characterization of the conformations of a single strand PNA and how these can be correlated to its capability in binding DNA/RNA. Employing Metadynamics we were able to better define conformational pre-organizations of the single strand PNA and γ-modified PNA otherwise unrevealed through classical molecular dynamics. Our simulations driven on backbone modified PNAs lead to the conclusion that this γ-functionalization affects the single strand preorganization and targeting properties to the DNA/RNA, in agreement with circular dichroism (CD) spectra obtained for this class of compounds. MD simulations on PNA:RNA dissociation and association mechanisms allowed to reveal the critical role of central bases and preorganization in the binding process.

Development of a peptide nucleic acid polymerase chain reaction clamping assay for semiquantitative evaluation of genetically modified organism content in food.

PubMed

Peano, C; Lesignoli, F; Gulli, M; Corradini, R; Samson, M C; Marchelli, R; Marmiroli, N

2005-09-15

In the present study a peptide nucleic acid (PNA)-mediated polymerase chain reaction (PCR) clamping method was developed and applied to the detection of genetically modified organisms (GMO), to test PCR products for band identity and to obtain a semiquantitative evaluation of GMO content. The minimal concentration of PNA necessary to block the PCR was determined by comparing PCRs containing a constant amount of DNA in the presence of increasing concentration of target-specific PNA. The lowest PNA concentration at which specific inhibition took place, by the inhibition of primer extension and/or steric hindrance, was the most efficient condition. Optimization of PCR clamping by PNA was observed by testing five different PNAs with a minimum of 13 bp to a maximum of 15 bp, designed on the target sequence of Roundup Ready soybean. The results obtained on the DNA extracted from Roundup Ready soybean standard flour were verified also on DNA extracted from standard flours of maize GA21, Bt176, Bt11, and MON810. A correlation between the PNA concentration necessary for inducing PCR clamping and the percentage of the GMO target sequence in the sample was found.

Focus on PNA Flexibility and RNA Binding using Molecular Dynamics and Metadynamics.

PubMed

Verona, Massimiliano Donato; Verdolino, Vincenzo; Palazzesi, Ferruccio; Corradini, Roberto

2017-02-17

Peptide Nucleic Acids (PNAs) can efficiently target DNA or RNA acting as chemical tools for gene regulation. Their backbone modification and functionalization is often used to increase the affinity for a particular sequence improving selectivity. The understanding of the trading forces that lead the single strand PNA to bind the DNA or RNA sequence is preparatory for any further rational design, but a clear and unique description of this process is still not complete. In this paper we report further insights into this subject, by a computational investigation aiming at the characterization of the conformations of a single strand PNA and how these can be correlated to its capability in binding DNA/RNA. Employing Metadynamics we were able to better define conformational pre-organizations of the single strand PNA and γ-modified PNA otherwise unrevealed through classical molecular dynamics. Our simulations driven on backbone modified PNAs lead to the conclusion that this γ-functionalization affects the single strand preorganization and targeting properties to the DNA/RNA, in agreement with circular dichroism (CD) spectra obtained for this class of compounds. MD simulations on PNA:RNA dissociation and association mechanisms allowed to reveal the critical role of central bases and preorganization in the binding process.

Formation of oligonucleotide-PNA-chimeras by template-directed ligation

NASA Technical Reports Server (NTRS)

Koppitz, M.; Nielsen, P. E.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

1998-01-01

DNA sequences have previously been reported to act as templates for the synthesis of PNA, and vice versa. A continuous evolutionary transition from an informational replicating system based on one polymer to a system based on the other would be facilitated if it were possible to form chimeras, that is molecules that contain monomers of both types. Here we show that ligation to form chimeras proceeds efficiently both on PNA and on DNA templates. The efficiency of ligation is primarily determined by the number of backbone bonds at the ligation site and the relative orientation of template and substrate strands. The most efficient reactions result in the formation of chimeras with ligation junctions resembling the structures of the backbones of PNA and DNA and with antiparallel alignment of both components of the chimera with the template, that is, ligations involving formation of 3'-phosphoramidate and 5'-ester bonds. However, double helices involving PNA are stable both with antiparallel and parallel orientation of the two strands. Ligation on PNA but not on DNA templates is, therefore, sometimes possible on templates with reversed orientation. The relevance of these findings to discussions of possible transitions between genetic systems is discussed.

Wintertime East Asian Jet Stream and Its Association with the Asian-Pacific Climate

NASA Technical Reports Server (NTRS)

Yang, Song; Lau, K.-M.; Kim, K.-M.

2000-01-01

Interannual variability of the wintertime East Asian westerly jet stream and the linkage between this variability and the Asian-Pacific climate are investigated. The study emphasizes on the variability of the jet core and its association with the Asian winter monsoon, tropical convection, upper tropospheric wave patterns, and the teleconnection of the jet with other climate systems. The relationship between the jet and North Pacific sea surface temperature pattern (SST) is also explored. NCEP/NCAR reanalysis, NASA GISS surface temperature, NASA GEOS reanalysis, NOAA reconstructed SST, GPCP precipitation, and NOAA snow cover data sets are analyzed in this study. An index of the East Asian jet has been defined by the December-February means of the 200 mb zonal winds that are averaged within a box enclosing the jet maximum, which shifts only moderately from one year to another especially in the south-north direction. The jet links to a teleconnection pattern whose major climate anomalies appear over the Asian continent and western Pacific (west of the dateline). This pattern differs distinctly from the teleconnection pattern associated with El Nino/Southern Oscillation (ENSO), which causes the Pacific/North American pattern to the east of the dateline. A strong jet is accompanied clearly by an increase in the intensity of the atmospheric circulation over Asia and the Pacific. In particular, the winter monsoon strengthens over East Asia, leading to cold climate in the region, and convection intensifies over the tropical Asia-Australia sector. Changes in the jet are associated with broad-scale modification in the upper tropospheric wave patterns that leads to downstream climate anomalies over the eastern Pacific. Through this downstream influence, the East Asian jet causes climate signals in North America as well. A strong jet gives rise to warming and less snow cover in the western United States but reverse climate anomalies in the eastern part of the country, although these signals are relatively weaker than the jet-related anomalies in East Asia. There is a strong association between the East Asian jet and the North Pacific SST (NPSST). A strong jet is accompanied by a cooling in the extratropical Pacific and a warming in the tropical-subtropical Pacific. Evidence also indicates that the extratropical NPSST pattern plays a role in modulating the intensity of the jet stream. ENSO, the jet, and the NPSST are mutually interactive on certain time scales and such an interaction links closely to the climate anomalies in the Asian-Pacific-American regions.

Processes and mechanisms of persistent extreme precipitation events in East China

NASA Astrophysics Data System (ADS)

Zhai, Panmao; Chen, Yang

2014-11-01

This study mainly presents recent progresses on persistent extreme precipitation events (PEPEs) in East China. A definition focusing both persistence and extremity of daily precipitation is firstly proposed. An identification method for quasi-stationary regional PEPEs is then designed. By utilizing the identified PEPEs in East China, typical circulation configurations from the lower to the upper troposphere are confirmed, followed by investigations of synoptic precursors for key components with lead time of 1-2 weeks. Two characteristic circulation patterns responsible for PEPEs in East China are identified: a double blocking high type and a single blocking high type. They may account for occurrence of nearly 80% PEPEs during last 60 years. For double blocking high type, about two weeks prior to PEPEs, two blockings developed and progressed towards the Ural Mountains and the Sea of Okhotsk, respectively. A northwestward progressive anomalous anticyclone conveying abundant moisture and eastward-extended South Asia High favoring divergence can be detected about one week in advance. A dominant summertime teleconnection over East Asia, East Asia/ Pacific (EAP) pattern, is deemed as another typical regime inducing PEPEs in the East China. Key elements of the EAP pattern initiated westward movement since one week prior to PEPEs. Eastward energy dispersion and poleward energy dispersion contributed to early development and subsequent maintenance of this teleconnection pattern, respectively. These typical circulation patterns and significant precursors may offer local forecasters some useful clues in identifying and predicting such high-impact precipitation events about 1-2 weeks in advance.

Kt/V and nPNA in pediatric peritoneal dialysis: a clinical or a mathematical association?

PubMed

Cano, F; Azocar, M; Cavada, G; Delucchi, A; Marin, V; Rodriguez, E

2006-01-01

The relationship between dialysis dose and nutrition is a field of particular interest in chronic pediatric dialysis (PD), and a positive correlation between ureaKt/V and nPNA has been published, suggesting a better nutritional status is associated with higher dialysis doses. However, this relationship has also been criticized as being the result of a mathematical coupling resulting from the same variables. The objective of the study was to establish the relationship between dialysis dose (Kt/V) and nutritional variables: daily protein intake (DPI), protein catabolic rate (PCR), protein equivalent of total nitrogen appearance (PNA) and nitrogen balance (NB) in dialyzed children. A cohort, prospective, observational study was carried out, for which 223 biochemical measurements were performed in 20 patients, ages 1 month to 14.3 years old (13 males), under PD for a 12-month period of follow-up. Monthly residual and total ureaKt/V, DPI, PCR, nPNA and NB were calculated, and the correlation between Kt/V and the nutritional parameters was evaluated. The Borah equation was used to calculate the nPNA. The data are reported as the mean plus or minus the standard error. All statistical comparisons were done with a paired t test, and two-way ANOVA for repeated measures was used to calculate correlations. A P <0.05 was considered significant. Mean total and residual Kt/V was 3.4+/-1.3 and 1.69+/-1.27, respectively; nPNA and PCR were 1.38+/-0.44 and 1.39+/-0.43 g/kg/day, daily protein intake (DPI) was 3.25+/-1.27 g/kg/day, and NB showed a value of 1.86+/-1.25 g/kg/day. A significant positive correlation was found between Kt/V and DPI, PCR, DPC and nPNA (all values P <0.0001), but no correlation was found between total and residual Kt/V vs. nitrogen balance ( P:ns). Total Kt/V showed a significant positive correlation with nPNA, but it did not show any correlation with nitrogen balance, suggesting that the relationship with nPNA is the result of a mathematical association calculated from the same variables.

Atlantic-induced pan-tropical climate change over the past three decades

NASA Astrophysics Data System (ADS)

Li, Xichen; Xie, Shang-Ping; Gille, Sarah T.; Yoo, Changhyun

2016-03-01

During the past three decades, tropical sea surface temperature (SST) has shown dipole-like trends, with warming over the tropical Atlantic and Indo-western Pacific but cooling over the eastern Pacific. Competing hypotheses relate this cooling, identified as a driver of the global warming hiatus, to the warming trends in either the Atlantic or Indian Ocean. However, the mechanisms, the relative importance and the interactions between these teleconnections remain unclear. Using a state-of-the-art climate model, we show that the Atlantic plays a key role in initiating the tropical-wide teleconnection, and the Atlantic-induced anomalies contribute ~55-75% of the tropical SST and circulation changes during the satellite era. The Atlantic warming drives easterly wind anomalies over the Indo-western Pacific as Kelvin waves and westerly anomalies over the eastern Pacific as Rossby waves. The wind changes induce an Indo-western Pacific warming through the wind-evaporation-SST effect, and this warming intensifies the La Niña-type response in the tropical Pacific by enhancing the easterly trade winds and through the Bjerknes ocean dynamical processes. The teleconnection develops into a tropical-wide SST dipole pattern. This mechanism, supported by observations and a hierarchy of climate models, reveals that the tropical ocean basins are more tightly connected than previously thought.

Low-frequency oscillations of the East Asia-Pacific teleconnection pattern and their impacts on persistent heavy precipitation in the Yangtze-Huai River valley

NASA Astrophysics Data System (ADS)

Li, Lei; Zhai, Panmao; Chen, Yang; Ni, Yunqi

2016-06-01

Based on the daily reanalysis data from NCEP-NCAR and daily precipitation data from the China National Meteorological Information Center, an ensemble empirical mode decomposition method is employed to extract the predominant oscillation modes of the East Asia-Pacific (EAP) teleconnection pattern. The influences of these low-frequency modes on persistent heavy precipitation in the Yangtze-Huai River (YHR) valley are investigated. The results indicate that the EAP pattern and rainfall in YHR valley both exhibit remarkable 10-30- and 30-60-day oscillations. The impacts of the EAP pattern on the YHR persistent heavy precipitation can be found on both the 10-30- and 30-60-day timescales—the 10-30-day scale for most cases. Composite analysis indicates that, on the 10-30-day timescale, formation of the EAP pattern in the lower and middle troposphere is determined by convective systems near the tropical western Pacific; whereas in the middle troposphere, the phase transition is jointly contributed by both the dispersion of zonal wave energies at higher latitudes and convective systems over the South China Sea. In the context of the 10-30-day EAP pattern, the anomalously abundant moisture is transported by an anomalous subtropical anticyclone system, and strong moisture convergence results from that anomalous anticyclone system and a cyclonic system in the midlatitude East Asia. Such a combination of systems persists for at least three days, contributing to the formation of persistent heavy precipitation in the YHR valley.

Teleconnection stationarity, variability and trends of the Southern Annular Mode (SAM) during the last millennium

NASA Astrophysics Data System (ADS)

Dätwyler, Christoph; Neukom, Raphael; Abram, Nerilie J.; Gallant, Ailie J. E.; Grosjean, Martin; Jacques-Coper, Martín; Karoly, David J.; Villalba, Ricardo

2017-11-01

The Southern Annular Mode (SAM) is the leading mode of atmospheric interannual variability in the Southern Hemisphere (SH) extra-tropics. Here, we assess the stationarity of SAM spatial correlations with instrumental and paleoclimate proxy data for the past millennium. The instrumental period shows that temporal non-stationarities in SAM teleconnections are not consistent across the SH land areas. This suggests that the influence of the SAM index is modulated by regional effects. However, within key-regions with good proxy data coverage (South America, Tasmania, New Zealand), teleconnections are mostly stationary over the instrumental period. Using different stationarity criteria for proxy record selection, we provide new austral summer and annual mean SAM index reconstructions over the last millennium. Our summer SAM reconstructions are very robust to changes in proxy record selection and the selection of the calibration period, particularly on the multi-decadal timescale. In contrast, the weaker performance and lower agreement in the annual mean SAM reconstructions point towards changing teleconnection patterns that may be particularly important outside the summer months. Our results clearly portend that the temporal stationarity of the proxy-climate relationships should be taken into account in the design of comprehensive regional and hemispherical climate reconstructions. The summer SAM reconstructions show no significant relationship to solar, greenhouse gas and volcanic forcing, with the exception of an extremely strong negative anomaly following the AD 1257 Samalas eruption. Furthermore, reconstructed pre-industrial summer SAM trends are very similar to trends obtained by model control simulations. We find that recent trends in the summer SAM lie outside the 5-95% range of pre-industrial natural variability.

Study of the global and regional climatic impacts of ENSO magnitude using SPEEDY AGCM

NASA Astrophysics Data System (ADS)

Dogar, Muhammad Mubashar; Kucharski, Fred; Azharuddin, Syed

2017-03-01

ENSO is considered as a strong atmospheric teleconnection that has pronounced global and regional circulation effects. It modifies global monsoon system, especially, Asian and African monsoons. Previous studies suggest that both the frequency and magnitude of ENSO events have increased over the last few decades resulting in a need to study climatic impacts of ENSO magnitude both at global and regional scales. Hence, to better understand the impact of ENSO amplitude over the tropical and extratropical regions focussing on the Asian and African domains, ENSO sensitivity experiments are conducted using ICTPAGCM (`SPEEDY'). It is anticipated that the tropical Pacific SST forcing will be enough to produce ENSO-induced teleconnection patterns; therefore, the model is forced using NINO3.4 regressed SST anomalies over the tropical Pacific only. SPEEDY reproduces the impact of ENSO over the Pacific, North and South America and African regions very well. However, it underestimates ENSO teleconnection patterns and associated changes over South Asia, particularly in the Indian region, which suggests that the tropical Pacific SST forcing is not sufficient to represent ENSO-induced teleconnection patterns over South Asia. Therefore, SST forcing over the tropical Indian Ocean together with air-sea coupling is also required for better representation of ENSO-induced changes in these regions. Moreover, results obtained by this pacemaker experiment show that ENSO impacts are relatively stronger over the Inter-Tropical Convergence Zone (ITCZ) compared to extratropics and high latitude regions. The positive phase of ENSO causes weakening in rainfall activity over African tropical rain belt, parts of South and Southeast Asia, whereas, the La Niña phase produces more rain over these regions during the summer season. Model results further reveal that ENSO magnitude has a stronger impact over African Sahel and South Asia, especially over the Indian region because of its significant impact over the tropical Atlantic and the Indian Ocean through Walker circulation. ENSO-induced negative (positive) NAO-like response and associated changes over Southern Europe and North Africa get significantly strong following increased intensity of El Niño (La Niña) in the northern (southern) hemisphere in the boreal winter (summer) season. We further find that ENSO magnitude significantly impacts Hadley and Walker circulations. The positive phase of ENSO (El Niño) overall strengthens Hadley cell and a reverse is true for the La Niña phase. ENSO-induced strengthening and weakening of Hadley cell induces significant impact over South Asian and African ITCZ convective regions through modification of ITCZ/monsoon circulation system.

Interdecadal variability of the Afro-Asian summer monsoon system

NASA Astrophysics Data System (ADS)

Li, Yi; Ding, Yihui; Li, Weijing

2017-07-01

The Afro-Asian summer monsoon is a zonally planetary-scale system, with a large-scale rainbelt covering Africa, South Asia and East Asia on interdecadal timescales both in the past century (1901-2014) and during the last three decades (1979-2014). A recent abrupt change of precipitation occurred in the late 1990s. Since then, the entire rainbelt of the Afro-Asia monsoon system has advanced northwards in a coordinated way. Consistent increases in precipitation over the Huanghe-Huaihe River valley and the Sahel are associated with the teleconnection pattern excited by the warm phase of the Atlantic Multidecadal Oscillation (AMO). A teleconnection wave train, with alternating cyclones/anticyclones, is detected in the upper troposphere. Along the teleconnection path, the configuration of circulation anomalies in North Africa is characterized by coupling of the upper-level anticyclone (divergence) with low-level thermal low pressure (convergence), facilitating the initiation and development of ascending motions in the Sahel. Similarly, in East Asia, a coupled circulation pattern also excites ascending motion in the Huanghe-Huaihe River valley. The synchronous increase in precipitation over the Sahel and Huanghe-Huaihe River valley can be attributed to the co-occurrences and in-phase changes of ascending motion. On the other hand, the warm phase of the AMO results in significant warming in the upper troposphere in North Africa and the northern part of East Asia. Such warming contributes to intensification of the tropical easterly jet through increasing the meridional pressure gradient both at the entrance region (East Asia) and the exit region (Africa). Accordingly, precipitation over the Sahel and Huanghe-Huaihe River valley intensifies, owing to ageostrophic secondary cells. The results of this study provide evidence for a consistent and holistic interdecadal change in the Afro-Asian summer monsoon.

Organophosphonate-based PNA-functionalization of silicon nanowires for label-free DNA detection.

PubMed

Cattani-Scholz, Anna; Pedone, Daniel; Dubey, Manish; Neppl, Stefan; Nickel, Bert; Feulner, Peter; Schwartz, Jeffrey; Abstreiter, Gerhard; Tornow, Marc

2008-08-01

We investigated hydroxyalkylphosphonate monolayers as a novel platform for the biofunctionalization of silicon-based field effect sensor devices. This included a detailed study of the thin film properties of organophosphonate films on Si substrates using several surface analysis techniques, including AFM, ellipsometry, contact angle, X-ray photoelectron spectroscopy (XPS), X-ray reflectivity, and current-voltage characteristics in electrolyte solution. Our results indicate the formation of a dense monolayer on the native silicon oxide that has excellent passivation properties. The monolayer was biofunctionalized with 12 mer peptide nucleic acid (PNA) receptor molecules in a two-step procedure using the heterobifunctional linker, 3-maleimidopropionic-acid-N-hydroxysuccinimidester. Successful surface modification with the probe PNA was verified by XPS and contact angle measurements, and hybridization with DNA was determined by fluorescence measurements. Finally, the PNA functionalization protocol was translated to 2 microm long, 100 nm wide Si nanowire field effect devices, which were successfully used for label-free DNA/PNA hybridization detection.

Achieve efficient nitrogen removal from real sewage in a plug-flow integrated fixed-film activated sludge (IFAS) reactor via partial nitritation/anammox pathway.

PubMed

Yang, Yandong; Zhang, Liang; Cheng, Jun; Zhang, Shujun; Li, Baikun; Peng, Yongzhen

2017-09-01

This study tested the feasibility of plug-flow integrated fixed-film activated sludge (IFAS) reactor in applying sewage partial nitritation/anammox (PN/A) process. The IFAS reactor was fed with real pre-treated sewage (C/N ratio=1.3) and operated for 200days. High nitrogen removal efficiency of 82% was achieved with nitrogen removal rates of 0.097±0.019kgN/(m 3 ·d). Therefore, plug-flow IFAS reactor could be an alternative to applying sewage PN/A process. Besides, it was found that the stability of sewage PN/A process was significantly affected by residual ammonium. Nitrate accumulated in effluent and PN/A performance deteriorated when residual ammonium was below 1mg/L. On the contrary, long-term stable PN/A operation was achieved when residual ammonium was over 3mg/L. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multi-scale Quantitative Precipitation Forecasting Using Nonlinear and Nonstationary Teleconnection Signals and Artificial Neural Network Models

EPA Science Inventory

Global sea surface temperature (SST) anomalies can affect terrestrial precipitation via ocean-atmosphere interaction known as climate teleconnection. Non-stationary and non-linear characteristics of the ocean-atmosphere system make the identification of the teleconnection signals...

Gene delivery by a steroid-peptide nucleic acid conjugate.

PubMed

Rebuffat, Alexandre G; Nawrocki, Andrea R; Nielsen, Peter E; Bernasconi, Alessio G; Bernal-Mendez, Eloy; Frey, Brigitte M; Frey, Felix J

2002-09-01

We previously introduced a method called steroid-mediated gene delivery (SMGD), which uses steroid receptors as shuttles to facilitate the nuclear uptake of transfected DNA. Here, we describe a SMGD strategy with peptide nucleic acids (PNAs) that allowed linkage of a steroid molecule to a defined position in a plasmid without disturbing its gene expression. We synthesized and tested several bifunctional steroid derivatives [patent in process of nationalization] and finally selected the compound named DEX-bisPNA, a molecule consisting of a dexamethasone moiety linked to a PNA clamp (bisPNA) through a 30-atom chemical spacer. Dex-bisPNA binds to the glucocorticoid receptor (GR) as well as to reporter plasmids containing the corresponding PNA binding sites, translocates the GR from the cytoplasm into the nucleus, and increases the delivery of plasmid to the nucleus, resulting in enhanced GR-dependent expression of the reporter gene. The SMGD effect was more pronounced in growth-arrested cells than in proliferating cells. The specificity for the GR was shown by the reversion of the SMGD effect in the presence of dexamethasone as well as an enhanced expression in GR-positive cells but not in GR-negative cells. Thus, SMGD with PNA is a promising strategy for nonviral gene delivery into target tissues expressing specific steroid receptors.

Focus on PNA Flexibility and RNA Binding using Molecular Dynamics and Metadynamics

PubMed Central

Verona, Massimiliano Donato; Verdolino, Vincenzo; Palazzesi, Ferruccio; Corradini, Roberto

2017-01-01

Peptide Nucleic Acids (PNAs) can efficiently target DNA or RNA acting as chemical tools for gene regulation. Their backbone modification and functionalization is often used to increase the affinity for a particular sequence improving selectivity. The understanding of the trading forces that lead the single strand PNA to bind the DNA or RNA sequence is preparatory for any further rational design, but a clear and unique description of this process is still not complete. In this paper we report further insights into this subject, by a computational investigation aiming at the characterization of the conformations of a single strand PNA and how these can be correlated to its capability in binding DNA/RNA. Employing Metadynamics we were able to better define conformational pre-organizations of the single strand PNA and γ-modified PNA otherwise unrevealed through classical molecular dynamics. Our simulations driven on backbone modified PNAs lead to the conclusion that this γ-functionalization affects the single strand preorganization and targeting properties to the DNA/RNA, in agreement with circular dichroism (CD) spectra obtained for this class of compounds. MD simulations on PNA:RNA dissociation and association mechanisms allowed to reveal the critical role of central bases and preorganization in the binding process. PMID:28211525

Solid-Phase Synthesis of Difficult Purine-Rich PNAs through Selective Hmb Incorporation: Application to the Total Synthesis of Cell Penetrating Peptide-PNAs

PubMed Central

Tailhades, Julien; Takizawa, Hotake; Gait, Michael J.; Wellings, Don A.; Wade, John D.; Aoki, Yoshitsugu; Shabanpoor, Fazel

2017-01-01

Antisense oligonucleotide (ASO)-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino) and Spinraza (2′-O-methoxyethyl-phosphorothioate) in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA) chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders. However, the chemical synthesis of long PNAs, which are more target-specific, remains an ongoing challenge. Most of the reported methodology for the solid-phase synthesis of PNA suffer from poor coupling efficiency which limits production to short PNA sequences of less than 15 residues. Here, we have studied the effect of backbone modifications with Hmb (2-hydroxy-4-methoxybenzyl) and Dmb (2,4-dimethoxybenzyl) to ameliorate difficult couplings and reduce “on-resin” aggregation. We firstly synthesized a library of PNA dimers incorporating either Hmb or Dmb and identified that Hmb is superior to Dmb in terms of its ease of removal. Subsequently, we used Hmb backbone modification to synthesize a 22-mer purine-rich PNA, targeting dystrophin RNA splicing, which could not be synthesized by standard coupling methodology. Hmb backbone modification allowed this difficult PNA to be synthesized as well as to be continued to include a cell-penetrating peptide on the same solid support. This approach provides a novel and straightforward strategy for facile solid-phase synthesis of difficult purine-rich PNA sequences. PMID:29094037

Solid-Phase Synthesis of Difficult Purine-Rich PNAs through Selective Hmb Incorporation: Application to the Total Synthesis of Cell Penetrating Peptide-PNAs.

PubMed

Tailhades, Julien; Takizawa, Hotake; Gait, Michael J; Wellings, Don A; Wade, John D; Aoki, Yoshitsugu; Shabanpoor, Fazel

2017-01-01

Antisense oligonucleotide (ASO)-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino) and Spinraza (2'- O -methoxyethyl-phosphorothioate) in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA) chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders. However, the chemical synthesis of long PNAs, which are more target-specific, remains an ongoing challenge. Most of the reported methodology for the solid-phase synthesis of PNA suffer from poor coupling efficiency which limits production to short PNA sequences of less than 15 residues. Here, we have studied the effect of backbone modifications with Hmb (2-hydroxy-4-methoxybenzyl) and Dmb (2,4-dimethoxybenzyl) to ameliorate difficult couplings and reduce "on-resin" aggregation. We firstly synthesized a library of PNA dimers incorporating either Hmb or Dmb and identified that Hmb is superior to Dmb in terms of its ease of removal. Subsequently, we used Hmb backbone modification to synthesize a 22-mer purine-rich PNA, targeting dystrophin RNA splicing, which could not be synthesized by standard coupling methodology. Hmb backbone modification allowed this difficult PNA to be synthesized as well as to be continued to include a cell-penetrating peptide on the same solid support. This approach provides a novel and straightforward strategy for facile solid-phase synthesis of difficult purine-rich PNA sequences.

Fluorescence Detection of KRAS2 mRNA Hybridization in Lung Cancer Cells with PNA-Peptides Containing an Internal Thiazole Orange

PubMed Central

2015-01-01

We previously developed reporter-peptide nucleic acid (PNA)-peptides for sequence-specific radioimaging and fluorescence imaging of particular mRNAs in cells and tumors. However, a direct test for PNA-peptide hybridization with RNA in the cytoplasm would be desirable. Thiazole orange (TO) dye at the 5′ end of a hybridization agent shows a strong increase in fluorescence quantum yield when stacked upon a 5′ terminal base pair, in solution and in cells. We hypothesized that hybridization agents with an internal TO could distinguish a single base mutation in RNA. Thus, we designed KRAS2 PNA-IGF1 tetrapeptide agents with an internal TO adjacent to the middle base of the 12th codon, a frequent site of cancer-initiating mutations. Our molecular dynamics calculations predicted a disordered bulge with weaker hybridization resulting from a single RNA mismatch. We observed that single-stranded PNA-IGF1 tetrapeptide agents with an internal TO showed low fluorescence, but fluorescence escalated 5–6-fold upon hybridization with KRAS2 RNA. Circular dichroism melting curves showed ∼10 °C higher Tm for fully complementary vs single base mismatch TO-PNA-peptide agent duplexes with KRAS2 RNA. Fluorescence measurements of treated human lung cancer cells similarly showed elevated cytoplasmic fluorescence intensity with fully complementary vs single base mismatch agents. Sequence-specific elevation of internal TO fluorescence is consistent with our hypothesis of detecting cytoplasmic PNA-peptide:RNA hybridization if a mutant agent encounters the corresponding mutant mRNA. PMID:25180641

A First-Principles Approach to the Dynamics and Electronic Properties of p-Nitroaniline in Water.

PubMed

Cabral, Benedito J Costa; Coutinho, Kaline; Canuto, Sylvio

2016-06-09

Born-Oppenheimer molecular dynamics of p-nitroaniline (PNA) in water was carried out and the electronic structure was investigated by time-dependent density functional theory. Hydrogen bonding involving the PNA nitro and amine groups and the water molecules leads to an ∼160 cm(-1) red shift of the ν(N-O) and ν(N-H) stretching frequencies relative to the gas phase species. Our estimate for the peak position of the charge transfer (CT) band in the absorption spectrum of PNA in water (∼3.5 eV) is in good agreement with experimental data (3.3 eV). We have investigated the specific role played by local hydrogen bonding and electrostatic interactions on the electronic absorption spectrum. It is shown that although electrostatic interactions play a major role for explaining the structure of the PNA CT band in water, the theoretical prediction of the observed red shift is improved by the explicit consideration of local hydrogen bonding of PNA to water. For isolated PNA, we predict that the dipole moment of the second excited state (S2) is 9.6 D greater than ground state (S0) dipole, which is in good agreement with experimental information (8.2-9.3 D). Calculation of charge transfer indexes for the two first excitations of PNA in water indicates that despite the feature that a small fraction of S1 states (<5%) may exhibit some CT character, CT states in solution are mainly associated with S2 ← S0 transitions.

A combination of immunohistochemistry and molecular approaches improves highly sensitive detection of BRAF mutations in papillary thyroid cancer.

PubMed

Martinuzzi, Claudia; Pastorino, Lorenza; Andreotti, Virginia; Garuti, Anna; Minuto, Michele; Fiocca, Roberto; Bianchi-Scarrà, Giovanna; Ghiorzo, Paola; Grillo, Federica; Mastracci, Luca

2016-09-01

The optimal method for BRAF mutation detection remains to be determined despite advances in molecular detection techniques. The aim of this study was to compare, against classical Sanger sequencing, the diagnostic performance of two of the most recently developed, highly sensitive methods: BRAF V600E immunohistochemistry (IHC) and peptide nucleic-acid (PNA)-clamp qPCR. BRAF exon 15 mutations were searched in formalin-fixed paraffin-embedded tissues from 86 papillary thyroid carcinoma using the three methods. The limits of detection of Sanger sequencing in borderline or discordant cases were quantified by next generation sequencing. BRAF mutations were found in 74.4 % of cases by PNA, in 71 % of cases by IHC, and in 64 % of cases by Sanger sequencing. Complete concordance for the three methods was observed in 80 % of samples. Better concordance was observed with the combination of two methods, particularly PNA and IHC (59/64) (92 %), while the combination of PNA and Sanger was concordant in 55 cases (86 %). Sensitivity of the three methods was 99 % for PNA, 94.2 % for IHC, and 89.5 % for Sanger. Our data show that IHC could be used as a cost-effective, first-line method for BRAF V600E detection in daily practice, followed by PNA analysis in negative or uninterpretable cases, as the most efficient method. PNA-clamp quantitative PCR is highly sensitive and complementary to IHC as it also recognizes other mutations besides V600E and it is suitable for diagnostic purposes.

Solid-phase synthesis of difficult purine-rich PNAs through selective Hmb incorporation: Application to the total synthesis of cell penetrating peptide-PNAs

NASA Astrophysics Data System (ADS)

Tailhades, Julien; Takizawa, Hotake; Gait, Michael J.; Wellings, Don A.; Wade, John D.; Aoki, Yoshitsugu; Shabanpoor, Fazel

2017-10-01

Antisense oligonucleotide (ASO)-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino) and Spinraza (2’-O-methoxyethyl-phosphorothioate) in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA) chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders. However, the chemical synthesis of long PNAs, which are more target-specific, remains an ongoing challenge. Most of the reported methodology for the solid-phase synthesis of PNA suffer from poor coupling efficiency which limits production to short PNA sequences of less than 15 residues. Here we have studied the effect of backbone modifications with Hmb (2-hydroxy-4-methoxybenzyl) and Dmb (2,4-dimethoxybenzyl) to ameliorate difficult couplings and reduce “on-resin” aggregation. We firstly synthesized a library of PNA dimers incorporating either Hmb or Dmb and identified that Hmb is superior to Dmb in terms of its ease of removal. Subsequently, we used Hmb backbone modification to synthesize a 22-mer purine-rich PNA, targeting dystrophin RNA splicing, which could not be synthesized by standard coupling methodology. Hmb backbone modification allowed this difficult PNA to be synthesized as well as to be continued to include a cell-penetrating peptide on the same solid support. This approach provides a novel and straightforward strategy for facile solid-phase synthesis of difficult purine-rich PNA sequences.

FISH and PNA FISH for the diagnosis of Q fever endocarditis and vascular infections.

PubMed

Prudent, Elsa; Lepidi, Hubert; Angelakis, Emmanouil; Raoult, Didier

2018-06-13

Purpose. Endocarditis and vascular infections are common manifestations of persistent localized infection due to Coxiella burnetii and recently, fluorescence in situ hybridization (FISH) was proposed as an alternative tool for their diagnosis. In this study, we evaluated the efficiency of FISH in a series of valve and vascular samples infected by C. burnetii. Methods. We tested 23 C. burnetii -positive valves and thrombus samples obtained from patients with Q fever endocarditis. Seven aneurysms and thrombus specimens were retrieved from patients with Q fever vascular infection. Samples were analyzed by culture, immunochemistry and FISH with oligonucleotide and PNA probes targeting C. burnetii -specific 16S ribosomal RNA sequences. Results. Immunohistochemical analysis was positive for five (17%) samples with significantly more copies of C. burnetii DNA than the negative ones ( p= 0.02). FISH was positive for 13 (43%) samples and presented 43% and 40% sensitivity compared to qPCR and culture, respectively. PNA FISH detected C. burnetii in 18 (60%) samples and presented 60% and 55% sensitivity compared to qPCR and culture, respectively. Immunohistochemistry had 38% and 28% sensitivity compared to FISH and PNA FISH, respectively. Samples found positive by both immunohistochemistry and PNA FISH contained significantly more copies of C. burnetii DNA than the negative ones ( p= 0.03). Finally, PNA FISH was more sensitive than FISH (60% versus 43%) for the detection of C. burnetii Conclusion. We provide evidence that PNA FISH and FISH are important assays for the diagnosis of C. burnetii endocarditis and vascular infections. Copyright © 2018 American Society for Microbiology.

Analysis of the interdecadal variability of summer precipitation in central Japan using a reconstructed 106 year long oxygen isotope record from tree ring cellulose

NASA Astrophysics Data System (ADS)

Kurita, Naoyuki; Nakatsuka, Takeshi; Ohnishi, Keiko; Mitsutani, Takumi; Kumagai, Tomo'omi

2016-10-01

We present a unique proxy for reconstructing the interannual variability of summer precipitation associated with the quasi-stationary front (Baiu front) in central Japan. The rainfall from the Baiu front has a relatively lower oxygen isotopic composition than other types of nonfrontal precipitation. The variability in the oxygen isotopes in summer rainfall is closely related to the Baiu frontal activity. In this study we used a mechanistic tree ring isotope model to reconstruct a 106 year long oxygen isotopic composition of precipitation during the early rainy season (June) based on the oxygen isotopic compositions of the annual rings of Chamaecyparis obtusa Endl trees from central Japan. The year-to-year variations of the isotopes over the most recent 25 years are associated with several teleconnection patterns that often lead to the Baiu precipitation anomalies in central Japan (such as the Pacific-Japan (PJ) pattern, Silk Road pattern, and wave train pattern along the polar jet). Yet none of these external forcing mechanisms apply further back in time. From the 1950s to 1980s, the interannual isotopic variability is predominantly related to local factors such as anomalous intensification/weakening of the Bonin High. Before the 1950s, the variability of the oxygen isotopic composition of precipitation is mainly associated with a wave train pattern along the polar jet. The isotopic variability is predominantly linked to the PJ pattern, while the PJ index is correlated with El Niño-Southern Oscillation. These findings suggest that the teleconnection patterns influencing Baiu precipitation variability vary according to interdecadal time scales during the twentieth century.

Relationships between large-scale circulation patterns and carbon dioxide exchange by a deciduous forest

NASA Astrophysics Data System (ADS)

Zhang, Jingyong; Wu, Lingyun; Huang, Gang; Notaro, Michael

2011-02-01

In this study, we focus on a deciduous forest in central Massachusetts and investigate the relationships between global climate indices and CO2 exchange using eddy-covariance flux measurements from 1992 to 2007. Results suggest that large-scale circulation patterns influence the annual CO2 exchange in the forest through their effects on the local surface climate. Annual gross ecosystem exchange (GEE) in the forest is closely associated with spring El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO), previous fall Atlantic Multidecadal Oscillation (AMO), and previous winter East Pacific-North Pacific (EP-NP) pattern. Annual net ecosystem exchange (NEE) responds to previous fall AMO and PDO, while annual respiration (R) is impacted by previous fall ENSO and Pacific/North American Oscillation (PNA). Regressions based on these relationships are developed to simulate the annual GEE, NEE, and R. To avoid problems of multicollinearity, we compute a "Composite Index for GEE (CIGEE)" based on a linear combination of spring ENSO and PDO, fall AMO, and winter EP-NP and a "Composite Index for R (CIR)" based on a linear combination of fall ENSO and PNA. CIGEE, CIR, and fall AMO and PDO can explain 41, 27, and 40% of the variance of the annual GEE, R, and NEE, respectively. We further apply the methodology to two other northern midlatitude forests and find that interannual variabilities in NEE of the two forests are largely controlled by large-scale circulation patterns. This study suggests that global climate indices provide the potential for predicting CO2 exchange variability in the northern midlatitude forests.

Relationship between the North Pacific Gyre Oscillation and the onset of stratospheric final warming in the northern Hemisphere

NASA Astrophysics Data System (ADS)

Hu, Jinggao; Li, Tim; Xu, Haiming

2018-01-01

The seasonal timing or onset date of the stratospheric final warming (SFWOD) events has a considerable interannual variability. This paper reports a statistically significant relationship between the North Pacific Gyre Oscillation (NPGO) and SFWOD in the Northern Hemisphere in two sub-periods (1951-1978 and 1979-2015). Specifically, in the first (second) sub-period, the NPGO is negatively (positively) linked with SFWOD. Composite analyses associated with anomalous NPGO years are conducted to diagnose the dynamic processes of the NPGO-SFWOD link. During 1951-1978, positive NPGO years tend to strengthen the Pacific-North America (PNA) pattern in the mid-troposphere in boreal winter. The strengthened PNA pattern in February leads to strong planetary wave activity in the extratropical stratosphere from late February to March and causes the early onset of SFW in early April. By contrast, a strengthened Western Pacific pattern from January to early February in negative NPGO years causes a burst of planetary waves in both the troposphere and extratropical stratosphere from late January to mid-February and results in more winter stratospheric sudden warming events, which, in turn, leads to a dormant spring and a late onset of SFW in late April. During 1979-2015, positive (negative) NPGO years strongly strengthen (weaken) the mid-tropospheric Aleutian low and the Western Pacific pattern from January to mid-March, leading to increased (decreased) planetary wavenumber-1 activity in the stratosphere from mid- to late winter and thus more (less) winter stratospheric sudden warming events and late (early) onsets of SFW in early May (mid-April).

The exceptionally wet year of 2014 over Greece: a statistical and synoptical-atmospheric analysis over the region of Thessaloniki

NASA Astrophysics Data System (ADS)

Tolika, Konstantia; Maheras, Panagiotis; Anagnostopoulou, Christina

2018-05-01

The highest rainfall totals (912.2 mm) and the largest number of raindays (133 days), since 1958, were recorded in Thessaloniki during the year of 2014. Extreme precipitation heights were also observed on a seasonal, monthly and daily basis. The examined year presented the highest daily rainfall intensity, the maximum daily precipitation and the largest number of heavy precipitation days (greater than 10 mm), and it also exceeded the previous amounts of precipitation of very wet (95th percentile) and extremely wet (99th percentile) days. According to the automatic circulation type classification scheme that was used, it was found that during this exceptionally wet year, the frequency of occurrence of cyclonic types at the near surface geopotential level increases, while the same types decreased at a higher atmospheric level (500 hPa). The prevailing type was type C which is located at the centre of the study area (Greece), but several other cyclonic types changed during this year not only their frequency but also their percentage of rainfall as well as their daily precipitation intensity. It should be highlighted that these findings differentiated on the seasonal-scale analysis. Moreover, out of the three teleconnection patterns that were examined (Scandinavian Pattern, Eastern Mediterranean Teleconnection Pattern and North Sea-Caspian Pattern), the Scandinavian one (SCAND) was detected during the most of the months of 2014 meaning that it was highly associated with intense precipitation over Greece.

Establishing a reference range for triiodothyronine levels in preterm infants.

PubMed

Oh, Ki Won; Koo, Mi Sung; Park, Hye Won; Chung, Mi Lim; Kim, Min-ho; Lim, Gina

2014-10-01

Thyroid dysfunction affects clinical complications in preterm infants and older children. However, thyroid hormone replacement in preterm infants has no proven benefits, possibly owing to the lack of an appropriate reference range for thyroid hormone levels. We aimed to establish a reference range for triiodothyronine (T3) levels at 1-month postnatal age (PNA) in preterm infants. This retrospective study included preterm infants born at a tertiary referral neonatal center at gestational age (GA)<35 weeks with no apparent thyroid dysfunction, for 6 consecutive years, with follow-up from PNA 2 weeks to 16 weeks. Using thyroid function tests (TFT), the relationships between T3 levels and thyrotropin (TSH) and free thyroxine (fT4) levels, birth weight, GA, postmenstrual age (PMA), and PNA were examined. The conversion trend for fT4 to T3 was analyzed using the T3/fT4 ratio. Overall, 464 TFTs from 266 infants were analyzed, after excluding 65 infants with thyroid dysfunction. T3 levels increased with fT4 levels, birth weight, GA, PMA, and PNA but not with TSH levels. The T3/fT4 ratio also increased with GA, PNA, and PMA. The average T3 level at 1 month PNA was 72.56 ± 27.83 ng/dL, with significant stratifications by GA. Relatively low T3 and fT4 levels in preterm infants were considered normal, with T3 levels and conversion trends increasing with GA, PMA, and PNA. Further studies are required to confirm the role of the present reference range in thyroid hormone replacement therapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

Disruption of Higher Order DNA Structures in Friedreich’s Ataxia (GAA)n Repeats by PNA or LNA Targeting

PubMed Central

Bergquist, Helen; Rocha, Cristina S. J.; Álvarez-Asencio, Rubén; Nguyen, Chi-Hung; Rutland, Mark. W.; Smith, C. I. Edvard; Good, Liam; Nielsen, Peter E.; Zain, Rula

2016-01-01

Expansion of (GAA)n repeats in the first intron of the Frataxin gene is associated with reduced mRNA and protein levels and the development of Friedreich’s ataxia. (GAA)n expansions form non-canonical structures, including intramolecular triplex (H-DNA), and R-loops and are associated with epigenetic modifications. With the aim of interfering with higher order H-DNA (like) DNA structures within pathological (GAA)n expansions, we examined sequence-specific interaction of peptide nucleic acid (PNA) with (GAA)n repeats of different lengths (short: n=9, medium: n=75 or long: n=115) by chemical probing of triple helical and single stranded regions. We found that a triplex structure (H-DNA) forms at GAA repeats of different lengths; however, single stranded regions were not detected within the medium size pathological repeat, suggesting the presence of a more complex structure. Furthermore, (GAA)4-PNA binding of the repeat abolished all detectable triplex DNA structures, whereas (CTT)5-PNA did not. We present evidence that (GAA)4-PNA can invade the DNA at the repeat region by binding the DNA CTT strand, thereby preventing non-canonical-DNA formation, and that triplex invasion complexes by (CTT)5-PNA form at the GAA repeats. Locked nucleic acid (LNA) oligonucleotides also inhibited triplex formation at GAA repeat expansions, and atomic force microscopy analysis showed significant relaxation of plasmid morphology in the presence of GAA-LNA. Thus, by inhibiting disease related higher order DNA structures in the Frataxin gene, such PNA and LNA oligomers may have potential for discovery of drugs aiming at recovering Frataxin expression. PMID:27846236

Study on the interactions between toxic nitroanilines and lysozyme by spectroscopic approaches and molecular modeling.

PubMed

Gu, Yunlan; Wang, Yanqing; Zhang, Hongmei

2018-05-05

Being exogenous environmental pollutants, nitroanilines (NAs) are highly toxic and have mutagenic and carcinogenic activity. Being lack of studies on interactions between NAs and lysozyme at molecular level, the binding interactions of lysozyme with o-nitroaniline (oNA), m-nitroaniline (mNA) and p-nitroaniline (pNA) were investigated by means of steady-state fluorescence, synchronous fluorescence, UV-vis absorption spectroscopy, as well as molecular modeling. The experimental results revealed that the fluorescence of lysozyme is quenched by oNA and mNA through a static quenching, while the fluorescence quenching triggered by pNA is a combined dynamic and static quenching. The number of binding sites (n) and the binding constant (K b ) corresponding thermodynamic parameters ΔH ⊖ , ΔS ⊖ , ΔG ⊖ at different temperatures were calculated. The reactions between NAs and lysozyme were spontaneous and entropy driven and the binding of NAs to lysozyme induced conformation changes of lysozyme. The difference of the position of -NO 2 group affected the binding and the binding constants K b decreased in the following pattern: K b (pNA) >K b (mNA) >K b (oNA). Molecular docking studies were performed to reveal the most favorable binding sites of NAs on lysozyme. Our recently results could offer mechanistic insights into the nature of the binding interactions between NAs and lysozyme and provide information about the toxicity risk of NAs to human health. Copyright © 2018 Elsevier B.V. All rights reserved.

The distribution of lectin receptor sites in human breast lesions.

PubMed

Skutelsky, E; Hoenig, S; Griffel, B; Alroy, J

1988-08-01

Conflicting data regarding the status of A, B, H and T antigens in epithelium of normal, mastopathies, fibroadenomas and carcinomas of the breast stimulated us to re-examine the carbohydrate residues in these condition. Currently, we extended the number of carbohydrate residues studied by using ten different biotinylated lectins as probes and avidin-biotin-peroxidase complex (ABC) as a visualant. In addition, the pattern of lectin staining of cancerous cells in primary and metastatic sites was compared. In primary and metastatic breast carcinomas, lectin receptor sites were stained more intensely with Concanavalia ensiformi agglutinin (*Con A), Ricinus communis agglutinin-I (RCA-I) and wheat germ agglutinin (WGA), than in normal breast, in mastopathies or in fibroadenomas. Cryptic receptor sites for peanut agglutinin (PNA) were stained in all cases of breast carcinomas, while free PNA sites stained only in a few cases of well-differentiated carcinomas. Receptors sites for Ulex europaeus agglutinin-I (UEA-I) stained non-malignant epithelium of patients with blood group H but did not stain malignant cells. The results show significant differences in lectin-binding patterns and staining intensities between normal and non-malignant, and malignant epithelial breast cells. Furthermore, these results indicate that in malignant cells, there is an increased content of sialic acid-rich carbohydrates but not of asialylated glycoconjugates.

Hydro-climate variability and teleconnection patterns during the last millennium in NW Africa, inferred from speleothem records

NASA Astrophysics Data System (ADS)

Ait Brahim, Y.; Cheng, H.; Sifeddine, A.; Wassenburg, J. A.; Khodri, M.; Cruz, F. W., Sr.

2017-12-01

In this study, we present new paleoclimate records from two well dated Moroccan speleothems. Our stalagmites were sampled from Ifoulki cave in the Western High Atlas Mountains in SW Morocco and Chaara cave in the Eastern Middle Atlas Mountains in NE Morocco. The new paleo-records cover the last 1000 years with a high resolution and reveal substantial swings of dry and humid periods with decadal to multidecadal frequencies. The Medieval Climate Anomaly (MCA) is characterized by generally dry conditions, while wetter conditions are recorded during the Little Ice Age (LIA) and a trend towards dry conditions during the 20th century. These observations are consistent with regional climate signals, providing new insights on common climate controls and teleconnection patterns in NW Africa. We emphasize that the hydro-climate conditions in Morocco remained under the influence of the Atlantic Multidecadal Oscillation (AMO) and the North Atlantic Oscillation (NAO). At longer timescales, we hypothesize that the generally warmer MCA and colder LIA influenced the regional climate in NW Africa through interactions with local mechanisms, such as the Sahara Low, which weakened and strengthened the mean moisture inflow from the Atlantic Ocean during the MCA and LIA respectively.

Design of Organic Nonlinear Optical Materials

DTIC Science & Technology

1990-06-01

Cocrystals 6) "Dinitrourea Polymorphs with SHG Properties" 7) "Symmetry Bias in H-Bonded Crystals" Part II a-c. Attached d. Cocrystallization can be used to...environment of PNA. PNA Cocrystals and Their Crystal Structures I PNA cocrystallizes with the following guest molecules: O-N - C N NO2 NO2 0 PhO=P-Ph...Refereed Journals (and not yet publishe) "Hydrogen-Bond Directed Cocrystallization and Molecular Recognition Properties of Diarylurea," M. C. Etter, Zofia

Gold Nanoparticles Used as Protein Scavengers Enhance Surface Plasmon Resonance Signal

PubMed Central

Ferreira de Macedo, Erenildo; Ducatti Formaggio, Daniela Maria; Salles Santos, Nivia; Batista Tada, Dayane

2017-01-01

Although several researchers had reported on methodologies for surface plasmon resonance (SPR) signal amplification based on the use of nanoparticles (NPs), the majority addressed the sandwich technique and low protein concentration. In this work, a different approach for SPR signal enhancement based on the use of gold NPs was evaluated. The method was used in the detection of two lectins, peanut agglutinin (PNA) and concanavalin A (ConA). Gold NPs were functionalized with antibodies anti-PNA and anti-ConA, and these NPs were used as protein scavengers in a solution. After being incubated with solutions of PNA or ConA, the gold NPs coupled with the collected lectins were injected on the sensor containing the immobilized antibodies. The signal amplification provided by this method was compared to the signal amplification provided by the direct coupling of PNA and ConA to gold NPs. Furthermore, both methods, direct coupling and gold NPs as protein scavengers, were compared to the direct detection of PNA and ConA in solution. Compared to the analysis of free protein, the direct coupling of PNA and ConA to gold NPs resulted in a signal amplification of 10–40-fold and a 13-fold decrease of the limit of detection (LOD), whereas the use of gold NPs as protein scavengers resulted in an SPR signal 40–50-times higher and an LOD 64-times lower. PMID:29186024

Doxorubicin-induced co-assembling nanomedicines with temperature-sensitive acidic polymer and their in-situ-forming hydrogels for intratumoral administration.

PubMed

Wan, Jiangshan; Geng, Shinan; Zhao, Hao; Peng, Xiaole; Zhou, Qing; Li, Han; He, Ming; Zhao, Yanbing; Yang, Xiangliang; Xu, Huibi

2016-08-10

Doxorubicin (DOX)-induced co-assembling nanomedicines (D-PNAx) with temperature-sensitive PNAx triblock polymers have been developed for regional chemotherapy against liver cancer via intratumoral administration in the present work. Owing to the formation of insoluble DOX carboxylate, D-PNAx nanomedicines showed high drug-loading and entrapment efficacy via a simple mixing of doxorubicin hydrochloride and PNAx polymers. The sustained releasing profile of D-PNA100 nanomedicines indicated that only 9.4% of DOX was released within 1day, and 60% was released during 10days. Based on DOX-induced co-assembling behavior and their temperature sensitive in-situ-forming hydrogels, D-PNA100 nanomedicines showed excellent antitumor activity against H22 tumor using intratumoral administration. In contrast to that by free DOX solution (1.13±0.04 times at 9days) and blank PNA100 (2.11±0.34 times), the tumor volume treated by D-PNA100 had been falling to only 0.77±0.13 times of original tumor volume throughout the experimental period. In vivo biodistribution of DOX indicated that D-PNA100 nanomedicines exhibited much stronger DOX retention in tumor tissues than free DOX solution via intratumoral injection. D-PNA100 nanomedicines were hopeful to be developed as new temperature sensitive in-situ-forming hydrogels via i.t. injection for regional chemotherapy. Copyright © 2016. Published by Elsevier B.V.

Promotion of double-duplex invasion of peptide nucleic acids through conjugation with nuclear localization signal peptide.

PubMed

Aiba, Yuichiro; Honda, Yuta; Komiyama, Makoto

2015-03-02

Pseudo-complementary peptide nucleic acid (pcPNA), as one of the most widely used synthetic DNA analogues, invades double-stranded DNA according to Watson-Crick rules to form invasion complexes. This unique mode of DNA recognition induces structural changes at the invasion site and can be used for a range of applications. In this paper, pcPNA is conjugated with a nuclear localization signal (NLS) peptide, and its invading activity is notably promoted both thermodynamically and kinetically. Thus, the double-duplex invasion complex is formed promptly at low pcPNA concentrations under high salt conditions, where the invasion otherwise never occurs. Furthermore, NLS-modified pcPNA is successfully employed for site-selective DNA scission, and the targeted DNA is selectively cleaved under conditions that are not conducive for DNA cutters using unmodified pcPNAs. This strategy of pcPNA modification is expected to be advantageous and promising for a range of in vitro and in vivo applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Future changes in rainfall associated with ENSO, IOD and changes in the mean state over Eastern Africa

NASA Astrophysics Data System (ADS)

Endris, Hussen Seid; Lennard, Christopher; Hewitson, Bruce; Dosio, Alessandro; Nikulin, Grigory; Artan, Guleid A.

2018-05-01

This study examines the projected changes in the characteristics of the El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) in terms of mean state, intensity and frequency, and associated rainfall anomalies over eastern Africa. Two regional climate models driven by the same four global climate models (GCMs) and the corresponding GCM simulations are used to investigate projected changes in teleconnection patterns and East African rainfall. The period 1976-2005 is taken as the reference for present climate and the far-future climate (2070-2099) under Representative Concentration Pathway 8.5 (RCP8.5) is analyzed for projected change. Analyses of projections based on GCMs indicate an El Niño-like (positive IOD-like) warming pattern over the tropical Pacific (Indian) Ocean. However, large uncertainties remain in the projected future changes in ENSO/IOD frequency and intensity with some GCMs show increase of ENSO/IOD frequency and intensity, and others a decrease or no/small change. Projected changes in mean rainfall over eastern Africa based on the GCM and RCM data indicate a decrease in rainfall over most parts of the region during JJAS and MAM seasons, and an increase in rainfall over equatorial and southern part of the region during OND, with the greatest changes in equatorial region. During ENSO and IOD years, important changes in the strength of the teleconnections are found. During JJAS, when ENSO is an important driver of rainfall variability over the region, both GCM and RCM projections show an enhanced La Niña-related rainfall anomaly compared to the present period. Although the long rains (MAM) have little association with ENSO in the reference period, both GCMs and RCMs project stronger ENSO teleconnections in the future. On the other hand, during the short rains (OND), a dipole future change in rainfall teleconnection associated with ENSO and IOD is found, with a stronger ENSO/IOD related rainfall anomaly over the eastern part of the domain, but a weaker ENSO/IOD signal over the southern part of the region. This signal is consistent and robust in all global and regional model simulations. The projected increase in OND rainfall over the eastern horn of Africa might be linked with the mean changes in SST over Indian and Pacific Ocean basins and the associated Walker circulations.

Relationship between Precipitation Components and Teleconnection Patterns in the Iberian Peninsula

NASA Astrophysics Data System (ADS)

María Ruiz, Ana; Maqueda, Gregorio

2016-04-01

The study of precipitation components is of increasing interest due to the differences that involve each of the correspondent consequences. On one hand, the stratiform component, weak and light, causes regular and long-lasting precipitation. On the other hand, the convective one, stronger and intense, is associated with more local precipitation, produced in short periods of time. In this work, the separated components of precipitation, obtained through the distribution of cumulated rain as its intensity has been analyzed for five sectors with different climate characteristic in Spain. The sectors may initially be of Atlantic or Mediterranean influence, besides having others geographical and orographic dependence. The aim of this study is to determine the influence of different teleconnection patterns over the stratiform and convective precipitation for each sector. The dataset have been a 17 years time series (1998-2014) of hourly rain data from the AEMET network (Spanish Meteorological Agency) consistent of 63 rain gauge stations that cover all the study area. Results show, in autumn-winter season, a clear influence of NAO in the stratiform precipitation for every sector except the closest to the Mediterranean sea. High correlation between EA, SCAND and EA/WR patterns with the stratiform component also it is observed. In the case of convective precipitation only the WeMO index keeps some influence in the near Mediterranean sector.

In Vitro Assessment of a Peptide Nucleic Acid (PNA) - Peptide Conjugate Labeled With an Auger-Emitting Radionuclide for Prostate Cell Killing

DTIC Science & Technology

2005-02-01

agents that are designed to improve the survival rates for prostate cancer patients with metastatic disease. Survival rates for prostate cancer drop from...radioiodine is physically located in close proximity to the phosphate backbone of the oligonucleotides, and decay of the radionuclide can cause extensive...reaction, non- radioactive sodium iodide was reacted with chloramine -T to give the iodinated PNA 23. That material was identical to PNA 23 prepared from

Front-End Processing of Cell Lysates for Enhanced Chip-Based Detection

DTIC Science & Technology

2006-07-28

manipulation used in lab-on-a-chip devices. A small unknown sample is first mixed with the PNA surfactants (“PNAA”) to tag the DNA targets, and then the...unknown sample is first mixed with the PNA surfactants (hereafter referred to as “PNA amphiphiles” or “PNAA”) to tag the DNA targets, and then the...prolate ellipsoid, and mixed PNAA/SDS micelles form spherical micelles. On addition of complementary DNA, the PNAA/DNA duplexes do not participate in

Temporal-spatial characteristics of severe drought events in Southwest China and their relationships to teleconnection indices

NASA Astrophysics Data System (ADS)

Wang, P., III; Wu, C.; Hao, Y.; Xu, K.

2017-12-01

In the process of global warming, the frequency and intensity of a series of climate events (such as, precipitation, flood disaster, climate arid) are also being changed. Even in the today of advanced science and technology, the occurrence and severity of drought in China is still devastating impact on social and economic development. We studied the spatial and temporal variability of drought in southwestern China China and its relationships to teleconnection indices. We used the Palmer Drought Severity Index (PDSI) to investigate the variation in drought in southwestern China between 1961 and 2012 using the Mann-Kendall (MK), continuous wavelet transform (CWT) and the rotated empirical orthogonal function (REOF) methods. Additionally, We analyzed the relationships between the time variability of significant patterns and teleconnection indices. The PDSI shows that there is a trend of turning dry in west Tibet; while it is remarkably drying in junction of Yunnan, Guizhou, Sichuan, Chongqing provinces, and the drought in Spring is more severe than in autumn, with a changing oscillation period of 2-7a. It's found the drought strength reducing before rising without a obvious turning point. Also, the drought frequency staggered in spatial distribution, and a larger inter-annual difference. AO and SS are the most important factors among all the drought influence factors, the others differ from the importance.

[Evaluation of PNA-FISH method for direct identification of Candida species in blood culture samples and its potential impact on guidance of antifungal therapy].

PubMed

Doğan, Özlem; İnkaya, Ahmet Çağkan; Gülmez, Dolunay; Uzun, Ömrüm; Akova, Murat; Arıkan Akdağlı, Sevtap

2016-10-01

Early antifungal therapy has a major influence on survival in candidemia. Rapid identification of the species has importance for the treatment, prediction of the species-specific primary resistance and variable antifungal susceptibility. Recently, molecular-based methods attempt to reduce the time between the positive signal of a blood culture and identification of the fungus. PNA-FISH (Peptide nucleic acid fluorescence in situ hybridization) assay distinguishes a number of frequently isolated Candida species in groups following the growth in blood culture. The aim of this study was to investigate the correlation of the species identified by PNA-FISH with conventional identification methods in yeast positive blood cultures and its influence on the selection of antifungal therapy. Specimens of adult patients diagnosed as yeast with Gram stain in signal-positive blood cultures between August to December 2013, were included in the study. The strains were concomitantly cultivated by subculturing from the blood culture bottles onto solid media and identified by conventional methods (germ tube test, ID32C and morphology on cornmeal Tween 80 agar). Rapid species identification was performed by Yeast Traffic Light PNA-FISH, which generates green flourescence for Candida albicans and Candida parapsilosis, yellow for Candida tropicalis, and red for Candida krusei and Candida glabrata. C.tropicalis was identified as a single species whereas the others were identified in pairs. The time points when the yeast positive blood culture bottle was received by the mycology laboratory and reporting of the species identification results by PNA-FISH and the conventional methods were recorded. Seven C.albicans, six C.glabrata, three C.parapsilosis, one C.tropicalis, one C.krusei, one Cryptococcus neoformans, one Saprochaete capitata (Blastoschizomyces capitatus), one C.albicans and Candida dubliniensis, one C.krusei and C.dubliniensis, and one C.glabrata and C.parapsilosis were identified by conventional methods in 23 specimens. Results of PNA-FISH and conventional methods were in full agreement in 19 of the 23 specimens (82.6%). Two specimens were negative by PNA-FISH and yielded S.capitata and C.neoformans which were not included in the test panel. In three specimens that were infected with multiple species, PNA-FISH detected only one of the species. On the other hand and in one specimen, PNA-FISH detected a second species (C.glabrata or C.krusei) that could not be isolated and identified conventionally. Species identification were obtained 72 hours (mean) earlier with PNA-FISH. PNA-FISH provided accurate species identification that were consistent with conventional methods. However and expectedly, it failed to detect species that were not included in the test panel. During the study period, 13 of the 23 patients have passed away. Apart from six patients died prior to blood culture positivity and the one that could not get any antifungal therapy during hospital stay, 16 patients received antifungal treatment. Of sixteen patients who received antifungal therapy, initial antifungal treatment was fluconazole for five and echinocandin for 10 patients. Fluconazole and amphotericin B combination was preferred for one patient. In this study, PNA-FISH result had an influence on the modification of the antifungal treatment of only for one patient in accordance with the clinical findings. We conclude that the utility of PNA-FISH method appeared to be limited in our center since the assay cannot differentiate C.albicans and C.parapsilosis, the two commonly isolated species among our candidemia isolates. However, advantages of the assay might be more pronounced for the centers where C.glabrata is a relatively more frequent species.

Thymocyte cyclic AMP and cyclic GMP response to treatment with metabolites issued from the lipoxygenase pathway.

PubMed

Mexmain, S; Cook, J; Aldigier, J C; Gualde, N; Rigaud, M

1985-08-01

Evidence has been presented that cGMP is the second messenger for the lipoxygenase metabolites 15-HETE and LTB4 in the mouse splenocyte and thymocyte. Incubation of splenocytes with 10(-7) to 10(-9) M 15-HETE caused a slight decrease in cAMP levels and an increase in cGMP levels after 10 to 20 min. Mature PNA-, immature PNA+, and whole thymocytes treated with 10(-7) to 10(-10) M 15-HETE and 10(-11) M LTB4 showed an approximately 100% increase in cGMP production. In mixed lymphocyte reactions, 15-HETE- and LTB4-treated PNA+, PNA-, and whole thymocyte populations inhibited thymidine uptake by fresh allostimulated splenocytes. These results demonstrate that the eicosanoid-induced generation of suppressor cells follows a rise in lymphocyte cGMP levels.

Insights into peptide nucleic acid (PNA) structural features: The crystal structure of a d-lysine-based chiral PNA–DNA duplex

PubMed Central

Menchise, Valeria; De Simone, Giuseppina; Tedeschi, Tullia; Corradini, Roberto; Sforza, Stefano; Marchelli, Rosangela; Capasso, Domenica; Saviano, Michele; Pedone, Carlo

2003-01-01

Peptide nucleic acids (PNAs) are oligonucleotide analogues in which the sugar-phosphate backbone has been replaced by a pseudopeptide skeleton. They bind DNA and RNA with high specificity and selectivity, leading to PNA–RNA and PNA–DNA hybrids more stable than the corresponding nucleic acid complexes. The binding affinity and selectivity of PNAs for nucleic acids can be modified by the introduction of stereogenic centers (such as d-Lys-based units) into the PNA backbone. To investigate the structural features of chiral PNAs, the structure of a PNA decamer containing three d-Lys-based monomers (namely H-GpnTpnApnGpnAdlTdlCdlApnCpnTpn-NH2, in which pn represents a pseudopeptide link and dl represents a d-Lys analogue) hybridized with its complementary antiparallel DNA has been solved at a 1.66-Å resolution by means of a single-wavelength anomalous diffraction experiment on a brominated derivative. Thed-Lys-based chiral PNA–DNA (LPD) heteroduplex adopts the so-called P-helix conformation. From the substantial similarity between the PNA conformation in LPD and the conformations observed in other PNA structures, it can be concluded that PNAs possess intrinsic conformational preferences for the P-helix, and that their flexibility is rather restricted. The conformational rigidity of PNAs is enhanced by the presence of the chiral centers, limiting the ability of PNA strands to adopt other conformations and, ultimately, increasing the selectivity in molecular recognition. PMID:14512516

Antisense imaging of gene expression in the brain in vivo

NASA Astrophysics Data System (ADS)

Shi, Ningya; Boado, Ruben J.; Pardridge, William M.

2000-12-01

Antisense radiopharmaceuticals could be used to image gene expression in the brain in vivo, should these polar molecules be made transportable through the blood-brain barrier. The present studies describe an antisense imaging agent comprised of an iodinated peptide nucleic acid (PNA) conjugated to a monoclonal antibody to the rat transferrin receptor by using avidin-biotin technology. The PNA was a 16-mer antisense to the sequence around the methionine initiation codon of the luciferase mRNA. C6 rat glioma cells were permanently transfected with a luciferase expression plasmid, and C6 experimental brain tumors were developed in adult rats. The expression of the luciferase transgene in the tumors in vivo was confirmed by measurement of luciferase enzyme activity in the tumor extract. The [125I]PNA conjugate was injected intravenously in anesthetized animals with brain tumors and killed 2 h later for frozen sectioning of brain and film autoradiography. No image of the luciferase gene expression was obtained after the administration of either the unconjugated antiluciferase PNA or a PNA conjugate that was antisense to the mRNA of a viral transcript. In contrast, tumors were imaged in all rats administered the [125I]PNA that was antisense to the luciferase sequence and was conjugated to the targeting antibody. In conclusion, these studies demonstrate gene expression in the brain in vivo can be imaged with antisense radiopharmaceuticals that are conjugated to a brain drug-targeting system.

Fluorescence In Situ Hybridization with Peptide Nucleic Acid Probes for Rapid Identification of Candida albicans Directly from Blood Culture Bottles

PubMed Central

Rigby, Susan; Procop, Gary W.; Haase, Gerhard; Wilson, Deborah; Hall, Geraldine; Kurtzman, Cletus; Oliveira, Kenneth; Von Oy, Sabina; Hyldig-Nielsen, Jens J.; Coull, James; Stender, Henrik

2002-01-01

A new fluorescence in situ hybridization (FISH) method that uses peptide nucleic acid (PNA) probes for identification of Candida albicans directly from positive-blood-culture bottles in which yeast was observed by Gram staining (herein referred to as yeast-positive blood culture bottles) is described. The test (the C. albicans PNA FISH method) is based on a fluorescein-labeled PNA probe that targets C. albicans 26S rRNA. The PNA probe is added to smears made directly from the contents of the blood culture bottle and hybridized for 90 min at 55°C. Unhybridized PNA probe is removed by washing of the mixture (30 min), and the smears are examined by fluorescence microscopy. The specificity of the method was confirmed with 23 reference strains representing phylogenetically related yeast species and 148 clinical isolates covering the clinically most significant yeast species, including C. albicans (n = 72), C. dubliniensis (n = 58), C. glabrata (n = 5), C. krusei (n = 2), C. parapsilosis (n = 4), and C. tropicalis (n = 3). The performance of the C. albicans PNA FISH method as a diagnostic test was evaluated with 33 routine and 25 simulated yeast-positive blood culture bottles and showed 100% sensitivity and 100% specificity. It is concluded that this 2.5-h method for the definitive identification of C. albicans directly from yeast-positive blood culture bottles provides important information for optimal antifungal therapy and patient management. PMID:12037084

Climate indices strongly influence old-growth forest carbon exchange

Treesearch

Sonia Wharton; Matthias Falk

2016-01-01

We present a decade and a half (1998–2013) of carbon dioxide fluxes from an old-growth stand in the American Pacific Northwest to identify ecosystem-level responses to Pacific teleconnection patterns, including the El Niño/Southern Oscillation (ENSO). This study provides the longest, continuous record of old-growth eddy flux data to date from one of the longest running...

Label-Free Potentiometry for Detecting DNA Hybridization Using Peptide Nucleic Acid and DNA Probes

PubMed Central

Goda, Tatsuro; Singi, Ankit Balram; Maeda, Yasuhiro; Matsumoto, Akira; Torimura, Masaki; Aoki, Hiroshi; Miyahara, Yuji

2013-01-01

Peptide nucleic acid (PNA) has outstanding affinity over DNA for complementary nucleic acid sequences by forming a PNA-DNA heterodimer upon hybridization via Watson-Crick base-pairing. To verify whether PNA probes on an electrode surface enhance sensitivity for potentiometric DNA detection or not, we conducted a comparative study on the hybridization of PNA and DNA probes on the surface of a 10-channel gold electrodes microarray. Changes in the charge density as a result of hybridization at the solution/electrode interface on the self-assembled monolayer (SAM)-formed microelectrodes were directly transformed into potentiometric signals using a high input impedance electrometer. The charge readout allows label-free, reagent-less, and multi-parallel detection of target oligonucleotides without any optical assistance. The differences in the probe lengths between 15- to 22-mer dramatically influenced on the sensitivity of the PNA and DNA sensors. Molecular type of the capturing probe did not affect the degree of potential shift. Theoretical model for charged rod-like duplex using the Gouy-Chapman equation indicates the dominant effect of electrostatic attractive forces between anionic DNA and underlying electrode at the electrolyte/electrode interface in the potentiometry. PMID:23435052

Effects of Hypoxanthine Substitution in Peptide Nucleic Acids Targeting KRAS2 Oncogenic mRNA Molecules: Theory and Experiment

PubMed Central

Sanders, Jeffrey M.; Wampole, Matthew E.; Chen, Chang-Po; Sethi, Dalip; Singh, Amrita; Dupradeau, François-Yves; Wang, Fan; Gray, Brian D.; Thakur, Mathew L.; Wickstrom, Eric

2013-01-01

Genetic disorders can arise from single base substitutions in a single gene. A single base substitution for wild type guanine in the twelfth codon of KRAS2 mRNA occurs frequently to initiate lung, pancreatic, and colon cancer. We have observed single base mismatch specificity in radioimaging of mutant KRAS2 mRNA in tumors in mice by in vivo hybridization with radiolabeled peptide nucleic acid (PNA) dodecamers. We hypothesized that multi-mutant specificity could be achieved with a PNA dodecamer incorporating hypoxanthine, which can form Watson-Crick basepairs with adenine, cytosine, thymine, and uracil. Using molecular dynamics simulations and free energy calculations, we show that hypoxanthine substitutions in PNAs are tolerated in KRAS2 RNA-PNA duplexes where wild type guanine is replaced by mutant uracil or adenine in RNA. To validate our predictions, we synthesized PNA dodecamers with hypoxanthine, and then measured the thermal stability of RNA-PNA duplexes. Circular dichroism thermal melting results showed that hypoxanthine-containing PNAs are more stable in duplexes where hypoxanthine-adenine and hypoxanthine-uracil base pairs are formed than single mismatch duplexes or duplexes containing hypoxanthine-guanine opposition. PMID:23972113

Design of a targeted peptide nucleic acid prodrug to inhibit hepatic human microsomal triglyceride transfer protein expression in hepatocytes.

PubMed

Biessen, Erik A L; Sliedregt-Bol, Karen; 'T Hoen, Peter A Chr; Prince, Perry; Van der Bilt, Erica; Valentijn, A Rob P M; Meeuwenoord, Nico J; Princen, Hans; Bijsterbosch, Martin K; Van der Marel, Gijs A; Van Boom, Jacques H; Van Berkel, Theo J C

2002-01-01

In this study, we present the design and synthesis of an antisense peptide nucleic acid (asPNA) prodrug, which displays an improved biodistribution profile and an equally improved capacity to reduce the levels of target mRNA. The prodrug, K(GalNAc)(2)-asPNA, comprised of a 14-mer sequence complementary to the human microsomal triglyceride transfer protein (huMTP) gene, conjugated to a high-affinity tag for the hepatic asialoglycoprotein receptor (K(GalNAc)(2)). The prodrug was avidly bound and rapidly internalized by HepG2s. After iv injection into mice, K(GalNAc)(2)-asPNA accumulated in the parenchymal liver cells to a much greater extent than nonconjugated PNA (46% +/- 1% vs 3.1% +/- 0.5% of the injected dose, respectively). The prodrug was able to reduce MTP mRNA levels in HepG2 cells by 35-40% (P < 0.02) at 100 nM in an asialoglycoprotein receptor- and sequence-dependent fashion. In conclusion, hepatocyte-targeted PNA prodrugs combine a greatly improved tropism with an enhanced local intracellular availability and activity, making them attractive therapeutics to lower the expression level of hepatic target genes such as MTP.

PNA lectin for purifying mouse acinar cells from the inflamed pancreas.

PubMed

Xiao, Xiangwei; Fischbach, Shane; Fusco, Joseph; Zimmerman, Ray; Song, Zewen; Nebres, Philip; Ricks, David Matthew; Prasadan, Krishna; Shiota, Chiyo; Husain, Sohail Z; Gittes, George K

2016-02-17

Better methods for purifying human or mouse acinar cells without the need for genetic modification are needed. Such techniques would be advantageous for the specific study of certain mechanisms, such as acinar-to-beta-cell reprogramming and pancreatitis. Ulex Europaeus Agglutinin I (UEA-I) lectin has been used to label and isolate acinar cells from the pancreas. However, the purity of the UEA-I-positive cell fraction has not been fully evaluated. Here, we screened 20 widely used lectins for their binding specificity for major pancreatic cell types, and found that UEA-I and Peanut agglutinin (PNA) have a specific affinity for acinar cells in the mouse pancreas, with minimal affinity for other major pancreatic cell types including endocrine cells, duct cells and endothelial cells. Moreover, PNA-purified acinar cells were less contaminated with mesenchymal and inflammatory cells, compared to UEA-I purified acinar cells. Thus, UEA-I and PNA appear to be excellent lectins for pancreatic acinar cell purification. PNA may be a better choice in situations where mesenchymal cells or inflammatory cells are significantly increased in the pancreas, such as type 1 diabetes, pancreatitis and pancreatic cancer.

PNA lectin for purifying mouse acinar cells from the inflamed pancreas

PubMed Central

Xiao, Xiangwei; Fischbach, Shane; Fusco, Joseph; Zimmerman, Ray; Song, Zewen; Nebres, Philip; Ricks, David Matthew; Prasadan, Krishna; Shiota, Chiyo; Husain, Sohail Z.; Gittes, George K.

2016-01-01

Better methods for purifying human or mouse acinar cells without the need for genetic modification are needed. Such techniques would be advantageous for the specific study of certain mechanisms, such as acinar-to-beta-cell reprogramming and pancreatitis. Ulex Europaeus Agglutinin I (UEA-I) lectin has been used to label and isolate acinar cells from the pancreas. However, the purity of the UEA-I-positive cell fraction has not been fully evaluated. Here, we screened 20 widely used lectins for their binding specificity for major pancreatic cell types, and found that UEA-I and Peanut agglutinin (PNA) have a specific affinity for acinar cells in the mouse pancreas, with minimal affinity for other major pancreatic cell types including endocrine cells, duct cells and endothelial cells. Moreover, PNA-purified acinar cells were less contaminated with mesenchymal and inflammatory cells, compared to UEA-I purified acinar cells. Thus, UEA-I and PNA appear to be excellent lectins for pancreatic acinar cell purification. PNA may be a better choice in situations where mesenchymal cells or inflammatory cells are significantly increased in the pancreas, such as type 1 diabetes, pancreatitis and pancreatic cancer. PMID:26884345

PNA-encoded chemical libraries.

PubMed

Zambaldo, Claudio; Barluenga, Sofia; Winssinger, Nicolas

2015-06-01

Peptide nucleic acid (PNA)-encoded chemical libraries along with DNA-encoded libraries have provided a powerful new paradigm for library synthesis and ligand discovery. PNA-encoding stands out for its compatibility with standard solid phase synthesis and the technology has been used to prepare libraries of peptides, heterocycles and glycoconjugates. Different screening formats have now been reported including selection-based and microarray-based methods that have yielded specific ligands against diverse target classes including membrane receptors, lectins and challenging targets such as Hsp70. Copyright © 2015 Elsevier Ltd. All rights reserved.

Some lumbar sympathetic neurons develop a glutamatergic phenotype after peripheral axotomy with a note on VGLUT2-positive perineuronal baskets

PubMed Central

Brumovsky, Pablo R.; Seroogy, Kim B.; Lundgren, Kerstin H.; Watanabe, Masahiko; Hökfelt, Tomas; Gebhart, G. F.

2011-01-01

Glutamate is the main excitatory neurotransmitter in the nervous system, including in primary afferent neurons. However, to date a glutamatergic phenotype of autonomic neurons has not been described. Therefore, we explored the expression of vesicular glutamate transporters (VGLUTs) type 1, 2 and 3 in lumbar sympathetic chain (LSC) and major pelvic ganglion (MPG) of naïve BALB/C mice, as well as after pelvic nerve axotomy (PNA), using immunohistochemistry and in situ hybridization. Colocalization with activating transcription factor-3 (ATF-3), tyrosine hydroxylase (TH), vesicular acetylcholine transporter (VAChT) and calcitonin generelated peptide was also examined. Sham-PNA, sciatic nerve axotomy (SNA) or naïve mice were included. In naïve mice, VGLUT2-like immunoreactivity (LI) was only detected in fibers and varicosities in LSC and MPG; no ATF-3-immunoreactive (IR) neurons were visible. In contrast, PNA induced upregulation of VGLUT2 protein and transcript, as well as of ATF-3-LI in subpopulations of LSC neurons. Interestingly, VGLUT2-IR LSC neurons coexpressed ATF-3, and often lacked the noradrenergic marker TH. SNA only increased VGLUT2 protein and transcript in scattered LSC neurons. Neither PNA nor SNA upregulated VGLUT2 in MPG neurons. We also found perineuronal baskets immunoreactive either for VGLUT2 or the acetylcholinergic marker VAChT in non-PNA MPGs, usually around TH-IR neurons. VGLUT1-LI was restricted to some varicosities in MPGs, was absent in LSCs, and remained largely unaffected by PNA or SNA. This was confirmed by the lack of expression of VGLUT1 or VGLUT3 mRNAs in LSCs, even after PNA or SNA. Taken together, axotomy of visceral and non-visceral nerves results in a glutamatergic phenotype of some LSC neurons. In addition, we show previously non-described MPG perineuronal glutamatergic baskets. PMID:21596036

Why were Past North Atlantic Warming Conditions Associated with Drier Climate in the Western United States?

NASA Astrophysics Data System (ADS)

Wong, C. I.; Potter, G. L.; Montanez, I. P.; Otto-Bliesner, B. L.; Behling, P.; Oster, J. L.

2014-12-01

Investigating climate dynamics governing rainfall over the western US during past warmings and coolings of the last glacial and deglaciation is pertinent to understanding how precipitation patterns might change with future global warming, especially as the processes driving the global hydrological reorganization affecting this drought-prone region during these rapid temperature changes remain unresolved. We present model climates of the Bølling warm event (14,500 years ago) and Younger Dryas cool event (12,200 years ago) that i) uniquely enable the assessment of dueling hypothesis about the atmospheric teleconnections responsible for abrupt temperature shifts in the North Atlantic region to variations in moisture conditions across the western US, and ii) show that existing hypotheses about these teleconnections are unsupported. Modeling results show no evidence for a north-south shift of the Pacific winter storm track, and we argue that a tropical moisture source with evolving trajectory cannot explain alternation between wet/dry conditions, which have been reconstructed from the proxy record. Alternatively, model results support a new hypothesis that variations in the intensity of the winter storm track, corresponding to its expansion/contraction, can account for regional moisture differences between warm and cool intervals of the last deglaciation. Furthermore, we demonstrate that the mechanism forcing the teleconnection between the North Atlantic and western US is the same across different boundary conditions. In our simulation, during the last deglaciation, and in simulations of future warming, perturbation of the Rossby wave structure reconfigures the atmospheric state. This reconfiguration affects the Aleutian Low and high-pressure ridge over and off of the northern North American coastline driving variability in the storm track. Similarity between the processes governing the climate response during these distinct time intervals illustrates the robust nature of the teleconnection, a novel result that provides context for understanding the climate processes governing the response of moisture variability to future climate change.

Winter temperatures over the Korean Peninsula and East Asia: development of a new index and its application to seasonal forecast

NASA Astrophysics Data System (ADS)

Kim, Seon Tae; Sohn, Soo-Jin; Kug, Jong-Seong

2017-09-01

This study proposes a new index for monitoring and predicting winter temperatures of the Korean Peninsula based on the dominant atmospheric winter teleconnection patterns. The utilization of this index is further extended to the East Asian Winter Monsoon (EAWM) index because the new index is found to well represent the main feature of the EAWM circulation. Among the teleconnection patterns, the East Atlantic (EA) and Western Pacific (WP) patterns are found to be most strongly correlated with winter temperatures via their partial association with changes in sea level pressure (SLP) around the Korean Peninsula, i.e., the EA and WP patterns are associated with SLP variation over the Siberian High region and the Kuroshio extension region to the east of Japan, respectively. On the basis of this relationship, the two regions representing the northwest-to-southeast SLP gradients are determined to define the new index. It is found that the new index can represent the Korean winter temperatures consistently well regardless of their considerable decadal changes. When compared with the existing SLP-based EAWM indices, the new index shows the best performance in delineating winter air temperatures, not only in the Korean Peninsula but also in the entire East Asian region. We also assess the prediction skill of the new index with seasonal coupled forecast models of the APEC Climate Center of Korea and its capability to predict winter temperatures. This assessment shows that the new index has potential for operationally predicting and monitoring winter temperatures in Korea and the whole of East Asia.

Detecting primary precursors of January surface air temperature anomalies in China

NASA Astrophysics Data System (ADS)

Tan, Guirong; Ren, Hong-Li; Chen, Haishan; You, Qinglong

2017-12-01

This study aims to detect the primary precursors and impact mechanisms for January surface temperature anomaly (JSTA) events in China against the background of global warming, by comparing the causes of two extreme JSTA events occurring in 2008 and 2011 with the common mechanisms inferred from all typical episodes during 1979-2008. The results show that these two extreme events exhibit atmospheric circulation patterns in the mid-high latitudes of Eurasia, with a positive anomaly center over the Ural Mountains and a negative one to the south of Lake Baikal (UMLB), which is a pattern quite similar to that for all the typical events. However, the Eurasian teleconnection patterns in the 2011 event, which are accompanied by a negative phase of the North Atlantic Oscillation, are different to those of the typical events and the 2008 event. We further find that a common anomalous signal appearing in early summer over the tropical Indian Ocean may be responsible for the following late-winter Eurasian teleconnections and the associated JSTA events in China. We show that sea surface temperature anomalies (SSTAs) in the preceding summer over the western Indian Ocean (WIO) are intimately related to the UMLB-like circulation pattern in the following January. Positive WIOSSTAs in early summer tend to induce strong UMLB-like circulation anomalies in January, which may result in anomalously or extremely cold events in China, which can also be successfully reproduced in model experiments. Our results suggest that the WIOSSTAs may be a useful precursor for predicting JSTA events in China.

Comparative Effectiveness of Needle Aponeurotomy and Collagenase Injection for Dupuytren's Contracture: A Multicenter Study.

PubMed

Zhou, Chao; Hovius, Steven E R; Pieters, Adriana J; Slijper, Harm P; Feitz, Reinier; Selles, Ruud W

2017-09-01

Although the efficacy of collagenase clostridium histolyticum (CCH) injections has been demonstrated by randomized clinical trials, the relative effectiveness of CCH remains uncertain. Our aim was to compare the outcomes of CCH with those of percutaneous needle aponeurotomy (PNA) in daily clinical practice. We analyzed data from patients undergoing PNA or CCH between 2011 and 2014 at 7 practice sites in the Netherlands. We examined the degree of improvement in contracture and adverse effects at 6-12 weeks after surgery or the last injection. Additionally, we invited patients to complete the Michigan Hand Questionnaire before and at 6-12 months follow-up. To minimize the risk of bias, we used propensity score matching. Among 130 matched patients (93% Tubiana I or II) undergoing PNA (n = 46) and CCH (n = 84), improvement in contracture was similar: 26 degrees (65% improvement from baseline) for PNA versus 31 degrees (71%) for CCH for affected metacarpophalangeal joints ( P = 0.163). This was 16 degrees (50% improvement) versus 17 degrees (42%) for affected proximal interphalangeal joints ( P = 0.395), respectively. No serious adverse effects occurred in either of the 2 treatment groups. Of the mild adverse effects, only skin fissures and sensory disturbances were seen in both groups. Through 1-year follow-up, patients reported similar improvements in the overall Michigan Hand Questionnaire score (PNA 5.3 points versus CCH 4.9 points; P = 0.912). In patients with mild contractures (Tubiana I or II), CCH was as effective as PNA in reducing contractures. Both treatments were safe and improved hand function to a similar extent in daily practice.

Evaluation of dual-color fluorescence in situ hybridization with peptide nucleic acid probes for the detection of Mycobacterium tuberculosis and non-tuberculous mycobacteria in clinical specimens.

PubMed

Kim, Namhee; Lee, Seung Hee; Yi, Jongyoun; Chang, Chulhun L

2015-09-01

Peptide nucleic acid (PNA) probes are artificial DNA analogues with a hydrophobic nature that can penetrate the mycobacterial cell wall. We evaluated a FISH method for simultaneous detection and identification of Mycobacterium tuberculosis (MTB) and non-tuberculous mycobacteria (NTM) in clinical respiratory specimens using differentially labeled PNA probes. PNA probes targeting the mycobacterial 16S ribosomal RNA were synthesized. The cross-reactivity of MTB- and NTM-specific probes was examined with reference strains and 10 other frequently isolated bacterial species. A total of 140 sputum specimens were analyzed, comprising 100 MTB-positive specimens, 21 NTM-positive specimens, and 19 MTB/NTM-negative specimens; all of them were previously confirmed by PCR and culture. The PNA FISH test results were graded by using the United States Centers for Disease Control and Prevention-recommended scale and compared with the results from the fluorochrome acid-fast bacterial stain. The MTB- and NTM-specific PNA probes showed no cross-reactivity with other tested bacterial species. The test results demonstrated 82.9% agreement with the culture results with diagnostic sensitivity of 80.2% and diagnostic specificity of 100.0% (kappa=0.52, 95% confidence interval: 0.370-0.676). Dual-color PNA FISH showed high specificity for detecting and identifying mycobacteria in clinical specimens. However, because of its relatively low sensitivity, this method could be more applicable to culture confirmation. In application to direct specimens, the possibility of false-negative results needs to be considered.

DNA-nanostructure-assembly by sequential spotting

PubMed Central

2011-01-01

Background The ability to create nanostructures with biomolecules is one of the key elements in nanobiotechnology. One of the problems is the expensive and mostly custom made equipment which is needed for their development. We intended to reduce material costs and aimed at miniaturization of the necessary tools that are essential for nanofabrication. Thus we combined the capabilities of molecular ink lithography with DNA-self-assembling capabilities to arrange DNA in an independent array which allows addressing molecules in nanoscale dimensions. Results For the construction of DNA based nanostructures a method is presented that allows an arrangement of DNA strands in such a way that they can form a grid that only depends on the spotted pattern of the anchor molecules. An atomic force microscope (AFM) has been used for molecular ink lithography to generate small spots. The sequential spotting process allows the immobilization of several different functional biomolecules with a single AFM-tip. This grid which delivers specific addresses for the prepared DNA-strand serves as a two-dimensional anchor to arrange the sequence according to the pattern. Once the DNA-nanoarray has been formed, it can be functionalized by PNA (peptide nucleic acid) to incorporate advanced structures. Conclusions The production of DNA-nanoarrays is a promising task for nanobiotechnology. The described method allows convenient and low cost preparation of nanoarrays. PNA can be used for complex functionalization purposes as well as a structural element. PMID:22099392

Stratospheric Instrusion Catalog: A 10-Year Compilation of Events Identified by using TRACK with NASA's MERRA-2 Reanalysis

NASA Technical Reports Server (NTRS)

Knowland, K. Emma; Ott, Lesley E.; Duncan, Bryan N.; Wargan, Kris; Hodges, Kevin

2017-01-01

Stratospheric intrusions "the introduction of ozone-rich stratospheric air into the troposphere" have been linked with surface ozone air quality exceedances, especially at the high elevations in the western USA in springtime. However, the impact of stratospheric intrusions in the remaining seasons and over the rest of the USA is less clear. A new approach to the study of stratospheric intrusions uses NASA's Goddard Earth Observing System Model (GEOS) model and assimilation products with an objective feature tracking algorithm to investigate the atmospheric dynamics that generate stratospheric intrusions and the different mechanisms through which stratospheric intrusions may influence tropospheric chemistry and surface air quality seasonally over both the western and the eastern USA. A catalog of stratospheric intrusions identified in the MERRA-2 reanalysis was produced for the period 2004-2015 and validated against surface ozone observations (focusing on those which exceed the national air quality standard) and a recent data set of stratospheric intrusion-influenced air quality exceedance flags from the US Environmental Protection Agency (EPA). Considering not all ozone exceedances have been flagged by the EPA, a collection of stratospheric intrusions can support air quality agencies for more rapid identification of the impact of stratospheric air on surface ozone and demonstrates that future operational analyses may aid in forecasting such events. An analysis of the spatiotemporal variability of stratospheric intrusions over the continental US was performed, and while the spring over the western USA does exhibit the largest number of stratospheric intrusions affecting the lower troposphere, the number of intrusions in the remaining seasons and over the eastern USA is sizable. By focusing on the major modes of variability that influence weather in the USA, such as the Pacific North American (PNA) teleconnection index, predicative meteorological patterns associated with stratospheric intrusions and their regional effects on tropospheric ozone were identified. Improved understanding of the connections between large-scale climate variability and local-scale dynamically-driven air quality events may support improved seasonal prediction of such events.

Stratospheric Intrusion Catalog: A 10-year Compilation of Events Identified By Using an Objective Feature Tracking Model With NASA's MERRA-2 Reanalysis

NASA Astrophysics Data System (ADS)

Knowland, K. E.; Ott, L. E.; Duncan, B. N.; Wargan, K.; Hodges, K.

2017-12-01

Stratospheric intrusions - the introduction of ozone-rich stratospheric air into the troposphere - have been linked with surface ozone air quality exceedances, especially at the high elevations in the western USA in springtime. However, the impact of stratospheric intrusions in the remaining seasons and over the rest of the USA is less clear. A new approach to the study of stratospheric intrusions uses NASA's Goddard Earth Observing System Model (GEOS) model and assimilation products with an objective feature tracking algorithm to investigate the atmospheric dynamics that generate stratospheric intrusions and the different mechanisms through which stratospheric intrusions may influence tropospheric chemistry and surface air quality seasonally over both the western and the eastern USA. A catalog of stratospheric intrusions identified in the MERRA-2 reanalysis was produced for the period 2005-2014 and validated against surface ozone observations (focusing on those which exceed the national air quality standard) and a recent data set of stratospheric intrusion-influenced air quality exceedance flags from the US Environmental Protection Agency (EPA). Considering not all ozone exceedances have been flagged by the EPA, a collection of stratospheric intrusions can support air quality agencies for more rapid identification of the impact of stratospheric air on surface ozone and demonstrates that future operational analyses may aid in forecasting such events. An analysis of the spatiotemporal variability of stratospheric intrusions over the continental US was performed, and while the spring over the western USA does exhibit the largest number of stratospheric intrusions affecting the lower troposphere, the number of intrusions in the remaining seasons and over the eastern USA is sizable. By focusing on the major modes of variability that influence weather in the USA, such as the Pacific North American (PNA) teleconnection index, predicative meteorological patterns associated with stratospheric intrusions and their regional effects on tropospheric ozone were identified. Improved understanding of the connections between large-scale climate variability and local-scale dynamically-driven air quality events may support improved seasonal prediction of such events.

The effect of two types of El Niño on the southerly low-level jets in North America

Treesearch

Lejiang Yu; Shiyuan Zhong; Warren E. Heilman; Xindi Bian

2016-01-01

Low-level jets (LLJs) are frequent weather phenomena in many regions of North America and have profound impacts on precipitation and wind energy. We used a 31 year (1979-2010) three-hourly reanalysis data set to examine the teleconnection between southerly LLJ activity in North America and the two dominant patterns of the equatorial Pacific Ocean sea surface...

Influence of finite-time Lyapunov exponents on winter precipitation over the Iberian Peninsula

NASA Astrophysics Data System (ADS)

Garaboa-Paz, Daniel; Lorenzo, Nieves; Pérez-Muñuzuri, Vicente

2017-05-01

Seasonal forecasts have improved during the last decades, mostly due to an increase in understanding of the coupled ocean-atmosphere dynamics, and the development of models able to predict the atmosphere variability. Correlations between different teleconnection patterns and severe weather in different parts of the world are constantly evolving and changing. This paper evaluates the connection between winter precipitation over the Iberian Peninsula and the large-scale tropospheric mixing over the eastern Atlantic Ocean. Finite-time Lyapunov exponents (FTLEs) have been calculated from 1979 to 2008 to evaluate this mixing. Our study suggests that significant negative correlations exist between summer FTLE anomalies and winter precipitation over Portugal and Spain. To understand the mechanisms behind this correlation, summer anomalies of the FTLE have also been correlated with other climatic variables such as the sea surface temperature (SST), the sea level pressure (SLP) or the geopotential. The East Atlantic (EA) teleconnection index correlates with the summer FTLE anomalies, confirming their role as a seasonal predictor for winter precipitation over the Iberian Peninsula.

Influence of the May Southern annular mode on the South China Sea summer monsoon

NASA Astrophysics Data System (ADS)

Liu, Ting; Li, Jianping; Li, YanJie; Zhao, Sen; Zheng, Fei; Zheng, Jiayu; Yao, Zhixiong

2017-07-01

The possible impact of the May Southern Hemisphere (SH) annular mode (SAM) on the following South China Sea (SCS) summer monsoon (SCSSM) is examined. A close inverse relationship between the two is revealed in the observations. The simultaneous South Pacific dipole (SPD), a dipole-like sea surface temperature anomaly pattern in the South Pacific, acts as the "oceanic bridge" to preserve the May SAM signal and prolong it into June-September. Observational evidence and numerical simulations both demonstrate that the SPD communicates its large thermal inertia signal to the atmosphere, regulating the Southern Pacific Subtropical Jet (SPSJ) variability over eastern Australia. Corresponding to the adjustment of circulation associated with the SPSJ is a prominent tripolar cross-Pacific teleconnection pattern stretching from the SH middle-high latitudes into the NH East Asia coastal region, referred to as the South-North Pacific (SNP) teleconnection pattern. Wave ray tracing analysis manifests that the SNP acts as the "atmospheric bridge" to propagate the related wave energy across the equator and into the Maritime Continent and SCS monsoon region, modulating the vertical motion and middle-lower tropospheric flows, and favoring the out-of-phase variation of the SCSSM. Therefore, the "coupled oceanic-atmospheric bridge" process and the related Rossby wave energy transmission are possible mechanisms for the significant influence of the May SAM on the variability of the following SCSSM. Therefore, the May SAM provides a fresh insight into the prediction of the SCSSM from the perspective of the SH high latitudes.

GCM simulations of intraseasonal variability in the Pacific/North American region

NASA Technical Reports Server (NTRS)

Schubert, Siegfried; Suarez, Max; Park, Chung-Kyu; Moorthi, Shrinivas

1993-01-01

General circulation model (GCM) simulations of low-frequency variability with time scales of 20 to 70 days are analyzed for the Pacific sector during boreal winter. The GCM's leading mode in the upper-tropospheric zonal wind is associated with fluctuations of the East Asian jet; this mode resembles, in both structure and amplitude, the Pacific/North American (PNA) pattern found in the observations on these time scales. In both the model and observations, the PNA anomaly is characterized by: (1) a linear balance in the upper-tropospheric vorticity budget with no significant Rossby wave source in the tropics, (2) a barotropic conversion of kinetic energy from the time mean Pacific jet, and (3) a north/south displacement of the Pacific storm track. In the GCM, the latter is associated with synoptic eddy heat flux and latent heat anomalies that appear to contribute to a strong lower-tropospheric source of wave activity over the North Pacific. This is in contrast to the observations, which show only a weak source of wave activity in this region.

Applicability of one-stage partial nitritation and anammox in MBBR for anaerobically pre-treated municipal wastewater.

PubMed

Kouba, Vojtech; Widiayuningrum, P; Chovancova, L; Jenicek, P; Bartacek, J

2016-07-01

Energy consumption of municipal wastewater treatment plants can be reduced by the anaerobic pre-treatment of the main wastewater stream. After this pre-treatment, nitrogen can potentially be removed by partial nitritation and anammox (PN/A). Currently, the application of PN/A is limited to nitrogen-rich streams (>500 mg L(-1)) and temperatures 25-35 °C. But, anaerobically pretreated municipal wastewater is characterized by much lower nitrogen concentrations (20-100 mg L(-1)) and lower temperatures (10-25 °C). We operated PN/A under similar conditions: total ammonium nitrogen concentration 50 mg L(-1) and lab temperature (22 °C). PN/A was operated for 342 days in a 4 L moving bed biofilm reactor (MBBR). At 0.4 mg O2 L(-1), nitrogen removal rate 33 g N m(-3) day(-1) and 80 % total nitrogen removal efficiency was achieved. The capacity of the reactor was limited by low AOB activity. We observed significant anammox activity (40 g N m(-3) day(-1)) even at 12 °C, improving the applicability of PN/A for municipal wastewater treatment.

Sensitive immobilization-free electrochemical DNA sensor based on isothermal circular strand displacement polymerization reaction.

PubMed

Xuan, Feng; Luo, Xiaoteng; Hsing, I-Ming

2012-05-15

A highly sensitive electrochemical DNA sensor that requires no probe immobilization has been developed based on a target recycling mechanism utilizing a DNA polymerase with a strand displacement activity. The electrochemical detection is realized by taking advantage of the difference in diffusivity between a free ferrocene-labeled peptide nucleic acid (Fc-PNA) and a Fc-PNA hybridized with a complementary DNA, while the DNA polymerase-assisted target recycling leads to signal generation and amplification. The hybridization of the target DNA opens up a stem-loop template DNA with the Fc-PNA hybridized to its extruded 5' end and allows a DNA primer to anneal and be extended by the DNA polymerase, which results in sequential displacement of the target DNA and the Fc-PNA from the template DNA. The displaced target DNA will hybridize with another template DNA, triggering another round of primer extension and strand displacement. The released Fc-PNA, due to its neutral backbone, has much higher diffusivity towards a negatively charged electrode, compared to that when it is hybridized with a negatively charged DNA. Therefore, a significantly enhanced signal of Fc can be observed. The outstanding sensitivity and simplicity make this approach a promising candidate for next-generation electrochemical DNA sensing technologies. Copyright © 2012 Elsevier B.V. All rights reserved.

Zwitterionic polymer functionalization of polysulfone membrane with improved antifouling property and blood compatibility by combination of ATRP and click chemistry.

PubMed

Xiang, Tao; Lu, Ting; Xie, Yi; Zhao, Wei-Feng; Sun, Shu-Dong; Zhao, Chang-Sheng

2016-08-01

The chemical compositions are very important for designing blood-contacting membranes with good antifouling property and blood compatibility. In this study, we propose a method combining ATRP and click chemistry to introduce zwitterionic polymer of poly(sulfobetaine methacrylate) (PSBMA), negatively charged polymers of poly(sodium methacrylate) (PNaMAA) and/or poly(sodium p-styrene sulfonate) (PNaSS), to improve the antifouling property and blood compatibility of polysulfone (PSf) membranes. Attenuated total reflectance-Fourier transform infrared spectra, X-ray photoelectron spectroscopy and water contact angle results confirmed the successful grafting of the functional polymers. The antifouling property and blood compatibility of the modified membranes were systematically investigated. The zwitterionic polymer (PSBMA) grafted membranes showed good resistance to protein adsorption and bacterial adhesion; the negatively charged polymer (PNaSS or PNaMAA) grafted membranes showed improved blood compatibility, especially the anticoagulant property. Moreover, the PSBMA/PNaMAA modified membrane showed both antifouling property and anticoagulant property, and exhibited a synergistic effect in inhibiting blood coagulation. The functionalization of membrane surfaces by a combination of ATRP and click chemistry is demonstrated as an effective route to improve the antifouling property and blood compatibility of membranes in blood-contact. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Peptide nucleic acids rather than RNA may have been the first genetic molecule

NASA Technical Reports Server (NTRS)

Nelson, K. E.; Levy, M.; Miller, S. L.

2000-01-01

Numerous problems exist with the current thinking of RNA as the first genetic material. No plausible prebiotic processes have yet been demonstrated to produce the nucleosides or nucleotides or for efficient two-way nonenzymatic replication. Peptide nucleic acid (PNA) is a promising precursor to RNA, consisting of N-(2-aminoethyl)glycine (AEG) and the adenine, uracil, guanine, and cytosine-N-acetic acids. However, PNA has not yet been demonstrated to be prebiotic. We show here that AEG is produced directly in electric discharge reactions from CH(4), N(2), NH(3), and H(2)O. Electric discharges also produce ethylenediamine, as do NH(4)CN polymerizations. AEG is produced from the robust Strecker synthesis with ethylenediamine. The NH(4)CN polymerization in the presence of glycine leads to the adenine and guanine-N(9)-acetic acids, and the cytosine and uracil-N(1)-acetic acids are produced in high yield from the reaction of cyanoacetaldehyde with hydantoic acid, rather than urea. Preliminary experiments suggest that AEG may polymerize rapidly at 100 degrees C to give the polypeptide backbone of PNA. The ease of synthesis of the components of PNA and possibility of polymerization of AEG reinforce the possibility that PNA may have been the first genetic material.

Distinct winter patterns of tropical Pacific convection anomaly and the associated extratropical wave trains in the Northern Hemisphere

NASA Astrophysics Data System (ADS)

Ding, Shuoyi; Chen, Wen; Graf, Hans-F.; Guo, Yuanyuan; Nath, Debashis

2017-11-01

In this paper, distinct patterns of boreal winter convection anomalies over the tropical Pacific and associated wave trains in the extratropics are addressed. The first leading mode (EOF1) of convection anomalies as measured by outgoing longwave radiation demonstrates an east-west oscillation of deep convection with centers over the equatorial central Pacific (CP) and over the tropical western North Pacific and the Maritime Continent. The second leading mode (EOF2) is also a dipole pattern with opposite centers straddling 170°W, possibly modifying EOF1 to some extent. Combining the first two leading modes, five major categories of tropical convection anomalies can be identified for the period 1979/80-2012/13. The comparison between these five categories and the corresponding SST anomaly patterns indicates a nonlinear relationship between convection and SST. The combination of EOF1 and EOF2 with in-phase PCs exhibits an east-west dipole pattern with opposite signs over west of the dateline and the Maritime Continent. The negative phase of the two PCs, named La Niña pattern, induces a negative Pacific/North American—positive North Atlantic Oscillation teleconnection in the extratropics. Approximately opposite responses can be detected in its positive phase, named CP El Niño pattern. The negative PC2 superposing positive PC1, named EP El Niño pattern, shows the strongest convection anomalies with enhanced (depressed) convection over the eastern (western) Pacific and leads to a Tropical/Northern Hemisphere-like teleconnection pattern and an anomalous anticyclone extending from the North Pacific to the North Atlantic. The positive PC2 with neutral PC1, named western CP pattern, shows weakly enhanced convection to the west of the dateline as a response to local SST warming around the dateline. This convection anomaly pattern, although weak, is important and excites a northeastward wave train from the tropics to Greenland, resulting in surface air temperature cooling covering the northeastern North America and warmer and wetter conditions over Western Europe.

Electroactive chitosan nanoparticles for the detection of single-nucleotide polymorphisms using peptide nucleic acids.

PubMed

Kerman, Kagan; Saito, Masato; Tamiya, Eiichi

2008-08-01

Here we report an electrochemical biosensor that would allow for simple and rapid analysis of nucleic acids in combination with nuclease activity on nucleic acids and electroactive bionanoparticles. The detection of single-nucleotide polymorphisms (SNPs) using PNA probes takes advantage of the significant structural and physicochemical differences between the full hybrids and SNPs in PNA/DNA and DNA/DNA duplexes. Ferrocene-conjugated chitosan nanoparticles (Chi-Fc) were used as the electroactive indicator of hybridization. Chi-Fc had no affinity towards the neutral PNA probe immobilized on a gold electrode (AuE) surface. When the PNA probe on the electrode surface hybridized with a full-complementary target DNA, Chi-Fc electrostatically attached to the negatively-charged phosphate backbone of DNA on the surface and gave rise to a high electrochemical oxidation signal from ferrocene at approximately 0.30 V. Exposing the surface to a single-stranded DNA specific nuclease, Nuclease S1, was found to be very effective for removing the nonspecifically adsorbed SNP DNA. An SNP in the target DNA to PNA made it susceptible to the enzymatic digestion. After the enzymatic digestion and subsequent exposure to Chi-Fc, the presence of SNPs was determined by monitoring the changes in the electrical current response of Chi-Fc. The method provided a detection limit of 1 fM (S/N = 3) for the target DNA oligonucleotide. Additionally, asymmetric PCR was employed to detect the presence of genetically modified organism (GMO) in standard Roundup Ready soybean samples. PNA-mediated PCR amplification of real DNA samples was performed to detect SNPs related to alcohol dehydrogenase (ALDH). Chitosan nanoparticles are promising biomaterials for various analytical and pharmaceutical applications.

Oceanic Channel of the IOD-ENSO teleconnection over the Indo-Pacific Ocean

NASA Astrophysics Data System (ADS)

Yuan, Dongliang; Wang, Jing; Zhao, Xia; Zhou, Hui; Xu, Tengfei; Xu, Peng

2017-04-01

The lag correlations of observations and model simulated data that participate the Coupled Model Intercomparison Project phase-5 (CMIP5) are used to study the precursory teleconnection between the Indian Ocean Dipole (IOD) and the Pacific ENSO one year later through the Indonesian seas. The results suggest that Indonesian Throughflow (ITF) play an important role in the IOD-ENSO teleconnection. Numerical simulations using a hierarchy of ocean models and climate coupled models have shown that the interannual sea level depressions in the southeastern Indian Ocean during IOD force enhanced ITF to transport warm water of the Pacific warm pool to the Indian Ocean, producing cold subsurface temperature anomalies, which propagate to the eastern equatorial Pacific and induce significant coupled ocean-atmosphere evolution. The teleconnection is found to have decadal variability. Similar decadal variability has also been identified in the historical simulations of the CMIP5 models. The dynamics of the inter-basin teleconnection during the positive phases of the decadal variability are diagnosed to be the interannual variations of the ITF associated with the Indian Ocean Dipole (IOD). During the negative phases, the thermocline in the eastern equatorial Pacific is anomalously deeper so that the sea surface temperature anomalies in the cold tongue are not sensitive to the thermocline depth changes. The IOD-ENSO teleconnection is found not affected significantly by the anthropogenic forcing.

An evaluation of the proteolytic and lipolytic potential of Penicillium spp. isolated from traditional Greek sausages in submerged fermentation.

PubMed

Papagianni, Maria

2014-01-01

A number of novel Penicillium strains belonging to Penicillium nalgiovense, Penicillium solitum, Penicillium commune, Penicillium olsonii, and Penicillium oxalicum species, isolated from the surface of traditional Greek sausages, were evaluated for their proteolytic and lipolytic potential in a solid substrate first and next in submerged fermentations, using complex media. Extracellular proteolytic activity was assessed at acid, neutral, and alkaline pH, while the lipolytic activity was assessed using olive oil, the short-chain triacylglycerol tributyrin, and the long-chain triolein, as substrates. The study revealed that although closely related, the tested strains produce enzymes of distinct specificities. P. nalgiovense PNA9 produced the highest alkaline proteolytic activity (13.2 unit (U)/ml) and the highest lipolytic activity with tributyrin (92 U/ml). Comparisons with known sources show that proteases and/or lipases can be secreted effectively by some Penicillia (P. nalgiovense PNA4, PNA7, and PNA9 and P. solitum PSO1), and further investigations on their properties and characteristics would be promising.

Peptide-nucleic acids (PNAs) with pyrimido[4,5-d]pyrimidine-2,4,5,7-(1H,3H,6H,8H)-tetraone (PPT) as a universal base: their synthesis and binding affinity for oligodeoxyribonucleotides.

PubMed

Hirano, Taisuke; Kuroda, Kenji; Kataoka, Masanori; Hayakawa, Yoshihiro

2009-07-21

Peptide-nucleic acids (PNAs) including pyrimido[4,5-d]pyrimidine-2,4,5,7-(1H,3H,6H,8H)-tetraone (PPT) as a nucleobase were synthesized, and their binding affinity for the complementary oligodeoxyribonucleotides was investigated. We found that PNAs with one or two PPT(s) and natural nucleobases (i.e., adenine, cytosine, guanine, or thymine) have excellent binding affinity for oligodeoxyribonucleotides with complementary bases at the positions facing the natural nucleobases, and with adenine, cytosine, guanine, and thymine at the positions opposite PPT in PNAs. The binding affinity of the PPT-containing PNA is higher than or comparable to that of a PNA consisting of all complementary natural nucleobases, viz. a PNA with a suitable natural nucleobase in place of PPT in the PPT-containing PNA. Consequently, it was concluded that PPT serves as a useful universal base that can recognize all natural nucleobases.

An In Vitro Translation, Selection, and Amplification System for Peptide Nucleic Acids

PubMed Central

Brudno, Yevgeny; Birnbaum, Michael E.; Kleiner, Ralph E.; Liu, David R.

2009-01-01

Methods to evolve synthetic, rather than biological, polymers could significantly expand the functional potential of polymers that emerge from in vitro evolution. Requirements for synthetic polymer evolution include: (i) sequence-specific polymerization of synthetic building blocks on an amplifiable template; (ii) display of the newly translated polymer strand in a manner that allows it to adopt folded structures; (iii) selection of synthetic polymer libraries for desired binding or catalytic properties; and (iv) amplification of template sequences surviving selection in a manner that allows subsequent translation. Here we report the development of such a system for peptide nucleic acids (PNAs) using a set of twelve PNA pentamer building blocks. We validated the system by performing six iterated cycles of translation, selection, and amplification on a library of 4.3 × 108 PNA-encoding DNA templates and observed >1,000,000-fold overall enrichment of a template encoding a biotinylated (streptavidin-binding) PNA. These results collectively provide an experimental foundation for PNA evolution in the laboratory. PMID:20081830

Sequence dependent N-terminal rearrangement and degradation of peptide nucleic acid (PNA) in aqueous solution

NASA Technical Reports Server (NTRS)

Eriksson, M.; Christensen, L.; Schmidt, J.; Haaima, G.; Orgel, L.; Nielsen, P. E.

1998-01-01

The stability of the PNA (peptide nucleic acid) thymine monomer inverted question markN-[2-(thymin-1-ylacetyl)]-N-(2-aminoaminoethyl)glycine inverted question mark and those of various PNA oligomers (5-8-mers) have been measured at room temperature (20 degrees C) as a function of pH. The thymine monomer undergoes N-acyl transfer rearrangement with a half-life of 34 days at pH 11 as analyzed by 1H NMR; and two reactions, the N-acyl transfer and a sequential degradation, are found by HPLC analysis to occur at measurable rates for the oligomers at pH 9 or above. Dependent on the amino-terminal sequence, half-lives of 350 h to 163 days were found at pH 9. At pH 12 the half-lives ranged from 1.5 h to 21 days. The results are discussed in terms of PNA as a gene therapeutic drug as well as a possible prebiotic genetic material.

Efficacy, safety and immunological actions of butanol-extracted FAHF-2 on peanut anaphylaxis

PubMed Central

Srivastava, Kamal; Yang, Nan; Chen, Yuming; Lopez-Exposito, Ivan; Song, Ying; Goldfarb, Joseph; Zhan, Jixun; Sampson, Hugh; Li, Xiu-Min

2010-01-01

Background Therapies for peanut allergy (PNA) are urgently needed. Food Allergy Herbal Formula -2 (FAHF-2) has profound therapeutic effects in a murine peanut allergy model and is safe for food allergic adults in clinical trials. However the large FAHF-2 pill-load is not conducive to clinical studies in children. Thus refining FAHF-2 to decrease pill-load is essential for the inclusion of children in clinical trials and to facilitate studying FAHF-2 as a clinically useful botanical drug. Objectives Testing long term efficacy and safety of a butanol-purified extract of FAHF-2 (B-FAHF-2) in a murine model of PNA, and to explore its immunological mechanisms of action. Methods FAHF-2 was purified by butanol extraction. C3H/HeJ mice with established PNA received the 1st course of B-FAHF-2 at 6 mg, twice daily for 7 weeks (PNA/B-FAHF-2) or water (PNA/Sham) and were then challenged immediately after completing the treatment and 6 more times every 1–2 months post treatment up to week 50. Mice then received a second course of B-FAHF-2 treatment at week 52 and were challenged at week 65. In vivo and in vitro immunological effects on T, B and mast cells were also determined. Results Butanol purification reduced the volume of the effective dose ~5 fold. All PNA/B-FAHF-2 mice were completely protected from peanut anaphylaxis until the 5th challenge after the 1st course of treatment, as compared to PNA/sham mice. Partial protection persisted up to 50 weeks. A 2nd treatment course restored complete protection. B-FAHF-2 significantly suppressed Th2 cytokine, IgE and histamine levels in vivo, and showed direct inhibition of Th2, IgE-producing B cells and mast cell activation in vitro. B-FAHF-2 had a high margin of safety. Conclusion and clinical relevance B-FAHF-2 produced long-lasting protection against PN anaphylaxis for approximately half of the murine lifespan without side effects. B-FAHF-2 exhibited direct effects on multiple food allergy effector cells. PMID:21121976

Climate Teleconnections and Recent Patterns of Human and Animal Disease Outbreaks

DTIC Science & Technology

2012-01-24

chikungunya and Rift Valley fever occurred 2004–2009. Chikungunya and Rift Valley fever case locations were mapped to corresponding climate data...anomalies. We illustrated the time lag between the driving climate conditions and the timing of the first case of Rift Valley fever. Results showed that...eastern- and-central Pacific Islands, Ecuador , and Peru. Similarly, there is a tendency for drought to occur over a large area of Southeast Asia

Interdecadal modulation of El Niño teleconnection on monsoon Asia climate over the past five centuries

NASA Astrophysics Data System (ADS)

Li, J.; Xie, S. P.

2017-12-01

The El Niño influence on monsoon Asia climate weakened during the mid-20th century and strenthened substantially after the late 1970s. Exploring the nature of such an interdecadal variation is constrained by short instrumental records. Here we synthesize the Indo-Pacific tree-rings and coral records to reconstruct monsoon Asia temperature and moisture change during the past five centuries, and show that the interdecadal modulation of El Niño teleconnection on monsoon Asia climate is a robust feature beyond the instrumenal era. Comparison with proxy El Niño records indicates that the El Niño-monsoon Asia climate teleconnection is controlled by interdecadal changes in ENSO variance, with strong (weak) teleconnection in periods of high (low) variance, respectively.

The Signature of Southern Hemisphere Atmospheric Circulation Patterns in Antarctic Precipitation

PubMed Central

Thompson, David W. J.; van den Broeke, Michiel R.

2017-01-01

Abstract We provide the first comprehensive analysis of the relationships between large‐scale patterns of Southern Hemisphere climate variability and the detailed structure of Antarctic precipitation. We examine linkages between the high spatial resolution precipitation from a regional atmospheric model and four patterns of large‐scale Southern Hemisphere climate variability: the southern baroclinic annular mode, the southern annular mode, and the two Pacific‐South American teleconnection patterns. Variations in all four patterns influence the spatial configuration of precipitation over Antarctica, consistent with their signatures in high‐latitude meridional moisture fluxes. They impact not only the mean but also the incidence of extreme precipitation events. Current coupled‐climate models are able to reproduce all four patterns of atmospheric variability but struggle to correctly replicate their regional impacts on Antarctic climate. Thus, linking these patterns directly to Antarctic precipitation variability may allow a better estimate of future changes in precipitation than using model output alone. PMID:29398735

Ultrasensitive FRET-based DNA sensor using PNA/DNA hybridization.

PubMed

Yang, Lan-Hee; Ahn, Dong June; Koo, Eunhae

2016-12-01

In the diagnosis of genetic diseases, rapid and highly sensitive DNA detection is crucial. Therefore, many strategies for detecting target DNA have been developed, including electrical, optical, and mechanical methods. Herein, a highly sensitive FRET based sensor was developed by using PNA (Peptide Nucleic Acid) probe and QD, in which red color QDs are hybridized with capture probes, reporter probes and target DNAs by EDC-NHS coupling. The hybridized probe with target DNA gives off fluorescent signal due to the energy transfer from QD to Cy5 dye in the reporter probe. Compared to the conventional DNA sensor using DNA probes, the DNA sensor using PNA probes shows higher FRET factor and efficiency due to the higher reactivity between PNA and target DNA. In addition, to elicit the effect of the distance between the donor and the acceptor, we have investigated two types of the reporter probes having Cy5 dyes attached at the different positions of the reporter probes. Results show that the shorter the distance between QDs and Cy5s, the stronger the signal intensity. Furthermore, based on the fluorescence microscopy images using microcapillary chips, the FRET signal is enhanced to be up to 276% times stronger than the signal obtained using the cuvette by the fluorescence spectrometer. These results suggest that the PNA probe system conjugated with QDs can be used as ultrasensitive DNA nanosensors. Copyright © 2016. Published by Elsevier B.V.

Point-of-care detection and real-time monitoring of intravenously delivered drugs via tubing with an integrated SERS sensor

NASA Astrophysics Data System (ADS)

Wu, Hsin-Yu; Cunningham, Brian T.

2014-04-01

We demonstrate an approach for detection, identification, and kinetic monitoring of drugs flowing within tubing, through the use of a plasmonic nanodome array (PNA) surface. The PNA structures are fabricated using a low-cost nanoreplica molding process upon a flexible plastic substrate that is subsequently integrated with a flow cell that connects in series with ordinary intravenous (IV) drug delivery tubing. To investigate the potential clinical applications for point-of-care detection and real-time monitoring, we perform SERS detection of ten pharmaceutical compounds (hydrocodone, levorphanol, morphine, oxycodone, methadone, phenobarbital, dopamine, diltiazem, promethazine, and mitoxantrone). We demonstrate dose-dependent SERS signal magnitude, resulting in detection limits (ng ml-1) well below typical administered dosages (mg ml-1). Further, we show that the detected drugs are not permanently attached to the PNA surface, and thus our approach is capable of performing continuous monitoring of drug delivery as materials flow through IV tubing that is connected in series with the sensor. Finally, we demonstrate the potential co-detection of multiple drugs when they are mixed together, and show excellent reproducibility and stability of SERS measurements for periods extending at least five days. The capabilities reported here demonstrate the potential to use PNA SERS surfaces for enhancing the safety of IV drug delivery.We demonstrate an approach for detection, identification, and kinetic monitoring of drugs flowing within tubing, through the use of a plasmonic nanodome array (PNA) surface. The PNA structures are fabricated using a low-cost nanoreplica molding process upon a flexible plastic substrate that is subsequently integrated with a flow cell that connects in series with ordinary intravenous (IV) drug delivery tubing. To investigate the potential clinical applications for point-of-care detection and real-time monitoring, we perform SERS detection of ten pharmaceutical compounds (hydrocodone, levorphanol, morphine, oxycodone, methadone, phenobarbital, dopamine, diltiazem, promethazine, and mitoxantrone). We demonstrate dose-dependent SERS signal magnitude, resulting in detection limits (ng ml-1) well below typical administered dosages (mg ml-1). Further, we show that the detected drugs are not permanently attached to the PNA surface, and thus our approach is capable of performing continuous monitoring of drug delivery as materials flow through IV tubing that is connected in series with the sensor. Finally, we demonstrate the potential co-detection of multiple drugs when they are mixed together, and show excellent reproducibility and stability of SERS measurements for periods extending at least five days. The capabilities reported here demonstrate the potential to use PNA SERS surfaces for enhancing the safety of IV drug delivery. Electronic supplementary information (ESI) available: Fabrication of PNA substrates, fabrication details of the flow cell, details of FDTD simulation, characterization of the scattering volume, and detection of diltiazem diluted in DI water and PBS. See DOI: 10.1039/c4nr00027g

Psychometric Needs Assessment. Theory and Practice.

ERIC Educational Resources Information Center

Scissons, Edward H.

The Psychometric Needs Assessment (PNA) model was designed to provide a means of describing a target population and various sub-populations contained therein. The specific purpose of such description is to provide a guide to determination of the continuing educational programming needs of professionals. Major attributes of the PNA model are the…

24 CFR 905.300 - Capital fund submission requirements.

Code of Federal Regulations, 2014 CFR

2014-04-01

... PHA must complete a comprehensive physical needs assessment (PNA). (1) Applicability. Small PHAs (PHAs... included; (ii) The information is consistent with the needs identified in the PNA and data available to HUD... Assessment Program (SEMAP) (24 CFR part 985), and/or were identified as noncompliant with section 9(j...

Investigating the relationship between climate teleconnection patterns and soil moisture variability in the Rio Grande/Río Bravo del Norte basin using the NOAH land surface model

NASA Astrophysics Data System (ADS)

Khedun, C. P.; Mishra, A. K.; Bolten, J. D.; Giardino, J. R.; Singh, V. P.

2010-12-01

Soil moisture is an important component of the hydrological cycle. Climate variability patterns, such as the Pacific Decadal Oscillation (PDO), El Niño Southern Oscillation (ENSO), and Atlantic Multidecadal Oscillation (AMO) are determining factors on surface water availability and soil moisture. Understanding this complex relationship and the phase and lag times between climate events and soil moisture variability is important for agricultural management and water planning. In this study we look at the effect of these climate teleconnection patterns on the soil moisture across the Rio Grande/Río Bravo del Norte basin. The basin is transboundary between the US and Mexico and has a varied climatology - ranging from snow dominated in its headwaters in Colorado, to an arid and semi-arid region in its middle reach and a tropical climate in the southern section before it discharges into the Gulf of Mexico. Agricultural activities in the US and in northern Mexico are highly dependent on the Rio Grande and are extremely vulnerable to climate extremes. The treaty between the two countries does not address climate related events. The soil moisture is generated using the community NOAH land surface model (LSM). The LSM is a 1-D column model that runs in coupled or uncoupled mode, and it simulates soil moisture, soil temperature, skin temperature, snowpack depth, snow water equivalent, canopy water content, and energy flux and water flux of the surface energy and water balance. The North American Land Data Assimilation Scheme 2 (NLDAS2) is used to drive the model. The model is run for the period 1979 to 2009. The soil moisture output is validated against measured values from the different Soil Climate Analysis Network (SCAN) sites within the basin. The spatial and temporal variability of the modeled soil moisture is then analyzed using marginal entropy to investigate monthly, seasonal, and annual variability. Wavelet transform is used to determine the relation, phase difference, and lag times between climate teleconnection events and soil moisture. The results from this study will help agricultural scientists and water planners in both the US and Mexico in better managing the dwindling water resources of this transboundary basin.

The 2014 southeast Brazil austral summer drought: regional scale mechanisms and teleconnections

NASA Astrophysics Data System (ADS)

Coelho, Caio A. S.; de Oliveira, Cristiano Prestrelo; Ambrizzi, Tércio; Reboita, Michelle Simões; Carpenedo, Camila Bertoletti; Campos, José Leandro Pereira Silveira; Tomaziello, Ana Carolina Nóbile; Pampuch, Luana Albertani; Custódio, Maria de Souza; Dutra, Lívia Marcia Mosso; Da Rocha, Rosmeri P.; Rehbein, Amanda

2016-06-01

The southeast region of Brazil experienced in austral summer 2014 a major drought event leading to a number of impacts in water availability for human consumption, agricultural irrigation and hydropower production. This study aims to perform a diagnostic analysis of the observed climate conditions during this event, including an inspection of the occurred precipitation anomalies in the context of previous years, and an investigation of possible relationships with sea surface temperatures and atmospheric circulation patterns. The sea surface temperature analysis revealed that the southwestern South Atlantic Ocean region near the coast of southeast Brazil showed strong negative association with precipitation over southeast Brazil, indicating that increased sea temperatures in this ocean region are consistent with reduced precipitation as observed in summer 2014. The circulation analysis revealed prevailing anti-cyclonic anomalies at lower levels (850 hPa) with northerly anomalies to the west of southeast Brazil, channeling moisture from the Amazon towards Paraguay, northern Argentina and southern Brazil, and drier than normal air from the South Atlantic Ocean towards the southeast region of Brazil. This circulation pattern was found to be part of a large-scale teleconnection wave train linked with the subsidence branch of the Walker circulation in the tropical east Pacific, which in turn was generated by an anomalous tropical heat source in north/northeastern Australia. A regional Hadley circulation with an ascending branch to the south of the subsidence branch of the Walker circulation in the tropical east Pacific was identified as an important component connecting the tropical and extratropical circulation. The ascending branch of this Hadley circulation in the south Pacific coincided with an identified Rossby wave source region, which contributed to establishing the extratropical component of the large-scale wave train connecting the south Pacific and the Atlantic region surrounding southeast Brazil. This connection between the Pacific and the Atlantic was confirmed with Rossby ray tracing analyses. The local circulation response was associated to downward air motion (subsidence) over Southeast Brazil, contributing to the expressive negative precipitation anomalies observed during summer 2014, and leading to a major drought event in the historical context. The analysis of atmospheric and oceanic patterns of this event helped defining a schematic framework leading to the observed drought conditions in southeast Brazil, including the involved teleconnections, blocking high pressure, radiative and humidity transport effects.

The influence of El Niño-Southern Oscillation regimes on eastern African vegetation and its future implications under the RCP8.5 warming scenario

NASA Astrophysics Data System (ADS)

Fer, Istem; Tietjen, Britta; Jeltsch, Florian; Wolff, Christian

2017-09-01

The El Niño-Southern Oscillation (ENSO) is the main driver of the interannual variability in eastern African rainfall, with a significant impact on vegetation and agriculture and dire consequences for food and social security. In this study, we identify and quantify the ENSO contribution to the eastern African rainfall variability to forecast future eastern African vegetation response to rainfall variability related to a predicted intensified ENSO. To differentiate the vegetation variability due to ENSO, we removed the ENSO signal from the climate data using empirical orthogonal teleconnection (EOT) analysis. Then, we simulated the ecosystem carbon and water fluxes under the historical climate without components related to ENSO teleconnections. We found ENSO-driven patterns in vegetation response and confirmed that EOT analysis can successfully produce coupled tropical Pacific sea surface temperature-eastern African rainfall teleconnection from observed datasets. We further simulated eastern African vegetation response under future climate change as it is projected by climate models and under future climate change combined with a predicted increased ENSO intensity. Our EOT analysis highlights that climate simulations are still not good at capturing rainfall variability due to ENSO, and as we show here the future vegetation would be different from what is simulated under these climate model outputs lacking accurate ENSO contribution. We simulated considerable differences in eastern African vegetation growth under the influence of an intensified ENSO regime which will bring further environmental stress to a region with a reduced capacity to adapt effects of global climate change and food security.

Ocean and atmosphere teleconnections modulate east tropical Pacific productivity at late to middle Pleistocene terminations

NASA Astrophysics Data System (ADS)

Diz, Paula; Hernández-Almeida, Iván; Bernárdez, Patricia; Pérez-Arlucea, Marta; Hall, Ian R.

2018-07-01

The modern Eastern Equatorial Pacific (EEP) is a key oceanographic region for regulating the Earth's climate system, accounting for between 5-10% of global marine production whilst also representing a major source of carbon dioxide efflux to the atmosphere. Changes in ocean dynamics linked to the nutrient supply from the Southern Ocean have been suggested to have played a dominant role in regulating EEP productivity over glacial-interglacial timescales of the past 500 ka. Yet, the full extent of the climate and oceanic teleconnections and the mechanisms promoting the observed increase of productivity occurring at glacial terminations remain poorly understood. Here we present multi-proxy, micropaleontological, geochemical and sedimentological records from the easternmost EEP to infer changes in atmospheric patterns and oceanic processes potentially influencing regional primary productivity over glacial-interglacial cycles of the mid-late Pleistocene (∼0-650 ka). These proxy data support a leading role for the north-south migration of the Intertropical Convergence Zone (ITCZ) in shaping past productivity variability in the EEP. Productivity increases during glacial periods and notably peaks at major and "extra" glacial terminations (those occurring 1-2 precession cycles after some major terminations) coincident with the inferred southernmost position of the ITCZ. The comparison of our reconstructions with proxy records of climate variability suggests the intensification of related extratropical atmospheric and oceanic teleconnections during deglaciation events. These processes may have re-activated the supply of southern sourced nutrients to the EEP, potentially contributing to enhanced productivity in the EEP and thus counterbalancing the oceanic carbon dioxide outgassing at glacial terminations.

Wintertime East Asian Jet Stream and its Association with the Asian-Pacific-American Climate

NASA Technical Reports Server (NTRS)

Yang, Song; Lau, K.-M.; Kim, K.-M.

1999-01-01

The wintertime upper-tropospheric westerly jet stream over subtropical East Asia and western Pacific, often referred to as East Asian Jet (EAJ), is an important atmospheric circulation system in the Asian-Pacific-American (APA) region. It is characterized by variabilities on a wide range of time scales and exerts a strong impact on the weather and climate of the region. On the synoptic scale, the jet is closely linked to many phenomena such as cyclogenesis, frontogenesis, blocking, storm track activity, and the development of other atmospheric disturbances. On the seasonal time scale, the variation of the EAJ determines many characteristics of the seasonal transition of the atmospheric circulation over Asia. The variabilities of the jet on these time scales have been relatively well documented (e.g., Yeh et al. 1959, Palmen and Newton 1969; Zeng 1979). It has also been understood that the inter-annual variability of the EAJ is associated with many climate signals in the APA region. These signals include the persistent anomalies of the East Asian winter monsoon and the changes in diabatic heating and in the Hadley circulation (Bjerknes 1966; Chang and Lau 1980; Huang and Gambo 1982; Kang and Held 1986; Tao and Chen 1987; Lau et al. 1988; Yang and Webster 1990; Ding 1992; Webster and Yang 1992; Dong et al. 1999). However, many questions remain for the year-to-year variabilities of the jet and their relation to the APA climate. For example, what is the relationship between the EAJ and El Nino/Southern Oscillation (ENSO)? Will the jet and ENSO play different roles in modulating the APA climate? How is the jet linked to North Pacific sea surface temperature (SST) and the Pacific/North American (PNA) teleconnection pattern? In this study, we address several issues related to the wintertime EAJ with a focus on interannual time scales. We will examine the association between the jet core and ENSO, which has always been overshadowed by the relationship between ENSO and the upper-tropospheric winds over northern extratropics of the central Pacific. We will investigate the linkage of the jet to variabilities of the Asian winter monsoon, tropical convection, and upper tropospheric wave patterns. We will also explore the relationship between the jet core and extratropical S ST with an aim at providing helpful information for improving our understanding of the connection of the EAJ to surface boundary conditions. The analysis is expected to provide information that is helpful for improving regional climate predictions.

Tropospheric biennial oscillation and south Asian summer monsoon rainfall in a coupled model

NASA Astrophysics Data System (ADS)

Konda, Gopinadh; Chowdary, J. S.; Srinivas, G.; Gnanaseelan, C.; Parekh, Anant; Attada, Raju; Rama Krishna, S. S. V. S.

2018-06-01

In this study Tropospheric Biennial Oscillation (TBO) and south Asian summer monsoon rainfall are examined in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFSv2) hindcast. High correlation between the observations and model TBO index suggests that the model is able to capture most of the TBO years. Spatial patterns of rainfall anomalies associated with positive TBO over the south Asian region are better represented in the model as in the observations. However, the model predicted rainfall anomaly patterns associated with negative TBO years are improper and magnitudes are underestimated compared to the observations. It is noted that positive (negative) TBO is associated with La Niña (El Niño) like Sea surface temperature (SST) anomalies in the model. This leads to the fact that model TBO is El Niño-Southern Oscillation (ENSO) driven, while in the observations Indian Ocean Dipole (IOD) also plays a role in the negative TBO phase. Detailed analysis suggests that the negative TBO rainfall anomaly pattern in the model is highly influenced by improper teleconnections allied to IOD. Unlike in the observations, rainfall anomalies over the south Asian region are anti-correlated with IOD index in CFSv2. Further, summer monsoon rainfall over south Asian region is highly correlated with IOD western pole than eastern pole in CFSv2 in contrast to the observations. Altogether, the present study highlights the importance of improving Indian Ocean SST teleconnections to south Asian summer rainfall in the model by enhancing the predictability of TBO. This in turn would improve monsoon rainfall prediction skill of the model.

Identification of Dekkera bruxellensis (Brettanomyces) from Wine by Fluorescence In Situ Hybridization Using Peptide Nucleic Acid Probes

PubMed Central

Stender, Henrik; Kurtzman, Cletus; Hyldig-Nielsen, Jens J.; Sørensen, Ditte; Broomer, Adam; Oliveira, Kenneth; Perry-O'Keefe, Heather; Sage, Andrew; Young, Barbara; Coull, James

2001-01-01

A new fluorescence in situ hybridization method using peptide nucleic acid (PNA) probes for identification of Brettanomyces is described. The test is based on fluorescein-labeled PNA probes targeting a species-specific sequence of the rRNA of Dekkera bruxellensis. The PNA probes were applied to smears of colonies, and results were interpreted by fluorescence microscopy. The results obtained from testing 127 different yeast strains, including 78 Brettanomyces isolates from wine, show that the spoilage organism Brettanomyces belongs to the species D. bruxellensis and that the new method is able to identify Brettanomyces (D. bruxellensis) with 100% sensitivity and 100% specificity. PMID:11157265

Enhancement of cell-cell contact by a nonmitogenic lectin increases blastogenic response and IL-2 release by mitogen-stimulated mouse thymocytes.

PubMed

Favero, J; Marti, J; Dornand, J; Bonnafous, J C; Mani, J C

1986-03-01

We have examined the influence of peanut agglutinin (PNA), a lectin which agglutinates but does not stimulate mouse thymocytes, on the responsiveness of these cells to concanavalin A (Con A) or galactose oxidase stimulation. Binding low amounts of PNA on unseparated mouse thymocytes pretreated with neuraminidase highly enhances the mitogenic response and the level of interleukin 2 release in the culture medium upon Con A stimulation. We have shown that PNA present on the cell surface acts as a crosslinking agent which favors intercellular binding between accessory cells (macrophages) and thymocytes, leading through this enhanced cooperation by cell-cell contact to an enhanced blastogenic response.

Recent advances in peptide nucleic acid for cancer bionanotechnology.

PubMed

Wu, Jun-Chen; Meng, Qing-Chun; Ren, Hong-Mei; Wang, Hong-Tao; Wu, Jie; Wang, Qi

2017-06-01

Peptide nucleic acid (PNA) is an oligomer, in which the phosphate backbone has been replaced by a pseudopeptide backbone that is meant to mimic DNA. Peptide nucleic acids are of the utmost importance in the biomedical field because of their ability to hybridize with neutral nucleic acids and their special chemical and biological properties. In recent years, PNAs have emerged in nanobiotechnology for cancer diagnosis and therapy due to their high affinity and sequence selectivity toward corresponding DNA and RNA. In this review, we summarize the recent progresses that have been made in cancer detection and therapy with PNA biotechnology. In addition, we emphasize nanoparticle PNA-based strategies for the efficient delivery of drugs in anticancer therapies.

Interannual Variations in Arctic Winter Temperature: The Role of Global Scale Teleconnections

DTIC Science & Technology

2015-06-01

also advect warm air northward and eastward between Iceland and Scandinavia . Figure 7 shows the LTM patterns of global Z200 and shows the normal...with an extension of this warm anomaly into the subpolar regions of the North Atlantic (i.e., Baffin Bay- Scandinavia ). Weak positive anomalies in...positive anomalies over northern Siberia and Scandinavia . We speculate that these areas of positive and negative anomalies in Z850, and implied WAA, may

Recurrent Interannual Climate Modes and Teleconnection Linking North America Warm Season Precipitation Anomalies to Asia Summer Monsoon Variability

NASA Technical Reports Server (NTRS)

Lau, K. M.; Weng, H. Y.; Einaudi, Franco (Technical Monitor)

2001-01-01

In this paper, we present results showing that summertime precipitation anomalies over North America and East Asia may be linked via pan-Pacific teleconnection patterns, which are components of two dominant recurring global climate modes. The first mode (Mode-1) features an inverse relationship between rainfall anomaly over the US Midwest/central to the eastern/southeastern regions, coupled to a mid-tropospheric high-low pressure system over the northwest and southeast of the US, which regulates low level moisture transport from the Gulf of Mexico to the Midwest. The regional circulation pattern appears to be a part of a global climate mode spanning Eurasia, the North Pacific, North America, and the Atlantic. This mode is associated with coherent fluctuations of jetstream variability over East Asia, and Eurasia, SST in the North Pacific and the North Atlantic. While Mode-1 is moderately correlated with El Nino-Southern Oscillation (ENSO), it appears to be distinct from it, with strong influences from mid-latitude or possibly from higher latitude processes. Results show that Mode-1 not only has an outstanding contribution to the great flood of 1993, it has large contribution to the US precipitation anomalies in other years. Also noted is an apparent increase in influence of Mode-1 on US summertime precipitation in the last two decades since 1977.

Influence of the Western Pacific teleconnection pattern on Western North Pacific tropical cyclone activity

NASA Astrophysics Data System (ADS)

Choi, Ki-Seon; Moon, Il-Ju

2012-09-01

This study analyzes the characteristics of Western North Pacific (WNP) tropical cyclone (TC) activity and large-scale environments according to the Western Pacific (WP) teleconnection pattern in summer. In the positive WP phase, an anomalous cyclone and an anomalous anticyclone develop in the low and middle latitudes of the East Asia area, respectively. As a result, southeasterlies are reinforced in the northeast area of East Asia (including Korea and Japan), which facilitates the movement of TC to this area, whereas northwesterlies are reinforced in the southwest area of East Asia (including southern China and the Indochina Peninsula) which blocks the movement of TC to that area. Due to the spatial distribution of this reinforced pressure system, TCs that develop during the positive WP phase move and turn more to the northeast of the WNP than TCs which develop during the negative WP phase. The characteristics of this TC activity during the positive WP phase are associated with the upper tropospheric jet being located farther to the northeast. TCs during the negative WP phase mainly move to the west from the Philippines toward southern China and the Indochina Peninsula. Due to the terrain effect caused by the passage of TCs in mainland China, the intensity of TCs during the negative WP phase is weaker than those during the positive WP phase.

Coupled modes of rainfall over China and the pacific sea surface temperature in boreal summertime

NASA Astrophysics Data System (ADS)

Li, Chun; Ma, Hao

2011-09-01

In addition, the possible atmospheric teleconnections of the coupled rainfall and SST modes were discussed. For the ENSO-NC mode, anomalous low-pressure and high-pressure over the Asian continent induces moisture divergence over North China and reduces summer rainfall there. For the WTP-YRV mode, East Asia-Pacific teleconnection induces moisture convergence over the Yangtze River valley and enhances the summer rainfall there. The TPMM SST and the summer rainfall anomalies over the YRVL are linked by a circumglobal, wave-train-like, atmospheric teleconnection.

An observational and modeling study of the regional impacts of climate variability

NASA Astrophysics Data System (ADS)

Horton, Radley M.

Climate variability has large impacts on humans and their agricultural systems. Farmers are at the center of this agricultural network, but it is often agricultural planners---regional planners, extension agents, commodity groups and cooperatives---that translate climate information for users. Global climate models (GCMs) are a leading tool for understanding and predicting climate and climate change. Armed with climate projections and forecasts, agricultural planners adapt their decision-making to optimize outcomes. This thesis explores what GCMs can, and cannot, tell us about climate variability and change at regional scales. The question is important, since high-quality regional climate projections could assist farmers and regional planners in key management decisions, contributing to better agricultural outcomes. To answer these questions, climate variability and its regional impacts are explored in observations and models for the current and future climate. The goals are to identify impacts of observed variability, assess model simulation of variability, and explore how climate variability and its impacts may change under enhanced greenhouse warming. Chapter One explores how well Goddard Institute for Space Studies (GISS) atmospheric models, forced by historical sea surface temperatures (SST), simulate climatology and large-scale features during the exceptionally strong 1997--1999 El Nino Southern Oscillation (ENSO) cycle. Reasonable performance in this 'proof of concept' test is considered a minimum requirement for further study of variability in models. All model versions produce appropriate local changes with ENSO, indicating that with correct ocean temperatures these versions are capable of simulating the large-scale effects of ENSO around the globe. A high vertical resolution model (VHR) provides the best simulation. Evidence is also presented that SST anomalies outside the tropical Pacific may play a key role in generating remote teleconnections even during El Nino events. Based on the results from Chapter One, the analysis is expanded in several ways in Chapter Two. To gain a more complete and statistically meaningful understanding of ENSO, a 25 year time period is used instead of a single event. To gain a fuller understanding of climate variability, additional patterns are analyzed. Finally analysis is conducted at the regional scales that are of interest to farmers and agricultural planners. Key findings are that GISS ModelE can reproduce: (1) the spatial pattern associated with two additional related modes, the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO); (2) rainfall patterns in Indonesia; and (3) dynamical features such as sea level pressure (SLP) gradients and wind in the study regions. When run in coupled mode, the same model reproduces similar modes spatially but with reduced variance and weak teleconnections. Since Chapter Two identified Western Indonesia as the region where GCMs hold the most promise for agricultural applications, in Chapter Three a finer spatial and temporal scale analysis of ENSO's effects is presented. Agricultural decision-making is also linked to ENSO's climate effects. Early rainy season precipitation and circulation, and same-season planting and harvesting dates, are shown to be sensitive to ENSO. The locus of ENSO convergence and rainfall anomalies is shown to be near the axis of rainy season establishment, defined as the 6--8 mm/day isohyet, an approximate threshold for irrigated rice cultivation. As the axis tracks south and east between October and January, so do ENSO anomalies. Circulation anomalies associated with ENSO are shown to be similar to those associated with rainfall anomalies, suggesting that long lead-time ENSO forecasts may allow more adaptation than 'wait and see' methods, with little loss of forecast skill. Additional findings include: (1) rice and corn yields are lower (higher) during dry (wet) trimesters and El Nino (La Nina) years; and (2) a statistically significant negative relationship exists between malaria cases and ENSO. The final chapter adds climate change to the climate variability story. Under high CO2, the model able to capture ENSO dynamics---an atmospheric model coupled to the Cane-Zebiak ocean model ('C4' here)---generates more El Nino-like mean conditions in the tropical Pacific. These changes produce a 4x larger increase in maximum precipitation with warming in C4 than an atmospheric model with a slab ocean (Q4), dramatically enhancing the Pacific Hadley and Walker circulations, and through positive feedbacks, increasing the global temperature. Near Nordeste warming alone (Q4) produces added rainfall, which in C4 is partially cancelled out by El Nino-like changes in the Walker Cell. Both Q4 and C4 produce small changes in Indonesia, although C4 generates large circulation and precipitation anomalies over the Western Indian Ocean. C4 changes in the midlatitudes produce a very strong Pacific North American pattern (PNA) response that dominates a small positive AO change associated with Q4. These PNA changes produce increased rainfall over the Southeastern United States (SEUS) in C4. AO and NAO-like variability are also found to increase with enhanced CO2. This thesis highlights how climate variability influences regional climate variability, with an emphasis on four regions: Nordeste, Brazil, Western Indonesia, the Southeastern United States (SEUS), and the Mediterranean. It links El Nino-driven delay in the onset of rainy season drivers in Western Indonesia to decision-making about when to plant the year's largest crop. In a coupled configuration, the GISS GCM produces strong El Nino-like changes with global warming. This result suggests that the impacts---climatological and agricultural---of climate change may ultimately exceed the impacts of current variability. Somewhat paradoxically, these results indicate that one of the central manifestations of climate change is likely to be changes in patterns of climate variability and their regional impacts.

Influence of Gestational Age and Postnatal Age on Speech Sound Processing in NICU infants

PubMed Central

Key, Alexandra P.F.; Lambert, E. Warren; Aschner, Judy L.; Maitre, Nathalie L.

2012-01-01

The study examined the effect of gestational (GA) and postnatal (PNA) age on speech sound perception in infants. Auditory ERPs were recorded in response to speech sounds (CV syllables) in 50 infant NICU patients (born at 24–40 weeks gestation) prior to discharge. Efficiency of speech perception was quantified as absolute difference in mean amplitudes of ERPs in response to vowel (/a/–/u/) and consonant (/b/–/g/, /d/–/g/) contrasts within 150–250, 250–400, 400–700 ms after stimulus onset. Results indicated that both GA and PNA affected speech sound processing. These effects were more pronounced for consonant than vowel contrasts. Increasing PNA was associated with greater sound discrimination in infants born at or after 30 weeks GA, while minimal PNA-related changes were observed for infants with GA less than 30 weeks. Our findings suggest that a certain level of brain maturity at birth is necessary to benefit from postnatal experience in the first 4 months of life, and both gestational and postnatal ages need to be considered when evaluating infant brain responses. PMID:22332725

UV-Vis Spectroscopy and Dynamic Light Scattering Study of Gold Nanorods Aggregation

PubMed Central

Kanjanawarut, Roejarek; Yuan, Bo

2013-01-01

Gold nanorods (AuNRs) were used as spectroscopic sensing elements to detect specific DNA sequences with a single-base mismatch sensitivity. The assay was based on the observation that the stabilizing repulsive forces between CTA+-coated AuNRs can be removed by citrate ions, which causes aggregation among AuNRs; whereas nucleic acids of different structures[ i.e., peptide nucleic acid (PNA), single-stranded DNA (ssDNA), PNA-DNA complex, and double-stranded DNA (dsDNA)] can retard the aggregation. Moreover, the dsDNA PNA-DNA duplexes provide larger retardation than that by unhybridized ssDNA and PNA probe. This assay can differentiate single-base mismatched targets with base substitution at different locations (center and end) with AuNRs of a larger aspect ratio. Besides ultraviolet–visable spectroscopy measurement of particle assembly-induced plasmonic coupling that in turn provides a spectroscopic detection of the specific DNA, dynamic light scattering and transmission electron microscope (TEM) were used to measure smaller degree of aggregation that can reveal sodium citrate– and dsDNA–AuNRs interactions in fine detail. PMID:23902360

UV-vis spectroscopy and dynamic light scattering study of gold nanorods aggregation.

PubMed

Kanjanawarut, Roejarek; Yuan, Bo; XiaoDi, Su

2013-08-01

Gold nanorods (AuNRs) were used as spectroscopic sensing elements to detect specific DNA sequences with a single-base mismatch sensitivity. The assay was based on the observation that the stabilizing repulsive forces between CTA(+)-coated AuNRs can be removed by citrate ions, which causes aggregation among AuNRs; whereas nucleic acids of different structures[ i.e., peptide nucleic acid (PNA), single-stranded DNA (ssDNA), PNA-DNA complex, and double-stranded DNA (dsDNA)] can retard the aggregation. Moreover, the dsDNA PNA-DNA duplexes provide larger retardation than that by unhybridized ssDNA and PNA probe. This assay can differentiate single-base mismatched targets with base substitution at different locations (center and end) with AuNRs of a larger aspect ratio. Besides ultraviolet-visable spectroscopy measurement of particle assembly-induced plasmonic coupling that in turn provides a spectroscopic detection of the specific DNA, dynamic light scattering and transmission electron microscope (TEM) were used to measure smaller degree of aggregation that can reveal sodium citrate- and dsDNA-AuNRs interactions in fine detail.

Fluorescence emission and polarization analyses for evaluating binding of ruthenium metalloglycocluster to lectin and tetanus toxin c-fragment

NASA Astrophysics Data System (ADS)

Okada, Tomoko; Minoura, Norihiko

2010-02-01

We have developed a fluorescent ruthenium metalloglycocluster as a powerful molecular probe for evaluating a binding event between carbohydrates and lectins by fluorescence emission (FE) and fluorescence polarization (FP) analysis. The fluorescent ruthenium metalloglycoclusters, [Ru(bpy-2Gal)3] and [Ru(bpy-2Glc)3], possess clustered galactose and glucose surrounding the ruthenium center. Changes in FE and FP of these metalloglycoclusters were measured by adding each lectin (Peanut agglutinin (PNA), Ricinus communis agglutinin 120 (RCA), Concanavalin A (ConA), or Wheat germ agglutinin (WGA)) or tetanus toxin c-fragment (TCF). Following the addition of PNA, the FE spectrum of [Ru(bpy- 2Gal)3] showed new emission peak and the FP value of [Ru(bpy-2Gal)3] increased. Similarly, the FE spectrum of [Ru(bpy-2Glc)3] showed new emission peak and the FP value increased following the addition of ConA. Since other combinations of the metalloglycoclusters and lectin caused little change, specific bindings of galactose to PNA and glucose to ConA were proved by the FE and FP measurement. From nonlinear least-squares fitting, dissociation constants (Kd) of [Ru(bpy-2Gal)3] to PNA was 6.1 μM, while the Kd values of [Ru(bpy)2(bpy-2Gal)] to PNA was ca. 10-4 M. Therefore, the clustered carbohydrates were proved to increase affinity to lectins. Furthermore, the FP measurements proved specific binding of [Ru(bpy-2Gal)3] to TCF.

Tropopause Pressure May Explain California Droughts and Wet Period

NASA Astrophysics Data System (ADS)

Mazdiyasni, O.; AghaKouchak, A.

2017-12-01

Sea surface temperatures and teleconnection patterns such as El Nino/La Nina are considered the main culprits behind major California droughts. However, the underlying relationship between sea surface temperatures (SSTs) and precipitation anomalies is relatively weak. In 2015-2016 the most extreme El Nino did not lead to a wet season as expected, which triggered a series of studies on this topic. Here we show that tropopause level pressure in a region in the northeastern Pacific Ocean (dubbed the PARS-NEP region) plays a major role in whether California will experience a wet or dry year and often dominates the role of SST-based teleconnections. Our results indicate that pressure in the PARS-NEP region Granger-Causes precipitation in California during the wet season. We show that when pressure in the PARS-NEP region is in the lower (upper) tertile, 85% of wet seasons across California have a positive (negative) precipitation anomaly. The observed relationship between PARS-NEP and California precipitation is stronger than all the commonly used SST-based climatic indictors frequently used for understanding causes of droughts.

Coralline alga reveals first marine record of subarctic North Pacific climate change

USGS Publications Warehouse

Halfar, J.; Steneck, R.; Schone, B.; Moore, G.W.K.; Joachimski, M.; Kronz, A.; Fietzke, J.; Estes, James A.

2007-01-01

While recent changes in subarctic North Pacific climate had dramatic effects on ecosystems and fishery yields, past climate dynamics and teleconnection patterns are poorly understood due to the absence of century-long high-resolution marine records. We present the first 117-year long annually resolved marine climate history from the western Bering Sea/Aleutian Island region using information contained in the calcitic skeleton of the long-lived crustose coralline red alga Clathromorphum nereostratum, a previously unused climate archive. The skeletal ??18O-time series indicates significant warming and/or freshening of surface waters after the middle of the 20th century. Furthermore, the time series is spatiotemporally correlated with Pacific Decadal Oscillation (PDO) and tropical El Nio??-Southern Oscillation (ENSO) indices. Even though the western Bering Sea/Aleutian Island region is believed to be outside the area of significant marine response to ENSO, we propose that an ENSO signal is transmitted via the Alaskan Stream from the Eastern North Pacific, a region of known ENSO teleconnections. Copyright 2007 by the American Geophysical Union.

Synthesis and characterization of metastable, 20 nm-sized Pna2{sub 1}-LiCoPO{sub 4} nanospheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludwig, Jennifer; Nordlund, Dennis; Doeff, Marca M.

The majority of research activities on LiCoPO{sub 4} are focused on the phospho-olivine (space group Pnma), which is a promising high-voltage cathode material for Li-ion batteries. In contrast, comparably little is known about its metastable Pna2{sub 1} modification. Herein, we present a comprehensive study on the structure–property relationships of 15–20 nm Pna2{sub 1}-LiCoPO{sub 4} nanospheres prepared by a simple microwave-assisted solvothermal process. Unlike previous reports, the results indicate that the compound is non-stoichiometric and shows cation-mixing with Co ions on the Li sites, which provides an explanation for the poor electrochemical performance. Co L{sub 2,3}-edge X-ray absorption spectroscopic data confirmmore » the local tetrahedral symmetry of Co{sup 2+}. Comprehensive studies on the thermal stability using thermogravimetric analysis, differential scanning calorimetry, and in situ powder X-ray diffraction show an exothermic phase transition to olivine Pnma-LiCoPO{sub 4} at 527 °C. The influence of the atmosphere and the particle size on the thermal stability is also investigated. - Graphical abstract: Blue nano-sized Pna2{sub 1}-LiCoPO{sub 4,} featuring tetrahedrally-coordinated Co{sup 2+}, was synthesized in a rapid one-step microwave-assisted solvothermal process. The phase relation between this metastable and the stable polymorph was analyzed and electrochemical properties are discussed. - Highlights: • Preparation of uniform 15–20 nm nanospheres of metastable Pna2{sub 1}-LiCoPO{sub 4} polymorph. • Structure redetermination shows cation-mixing (Co blocking Li sites). • In situ investigation of phase transformation to olivine Pnma-LiCoPO{sub 4} at 527 °C. • Pna2{sub 1}-LiCoPO{sub 4} reemerges as a stable high-temperature phase above 800 °C. • X-ray absorption spectroscopy confirms local tetrahedral symmetry (T{sub d} Co{sup 2+}).« less

Climatic Data Integration and Analysis - Regional Approaches to Climate Change for Pacific Northwest Agriculture (REACCH PNA)

NASA Astrophysics Data System (ADS)

Seamon, E.; Gessler, P. E.; Flathers, E.; Sheneman, L.; Gollberg, G.

2013-12-01

The Regional Approaches to Climate Change for Pacific Northwest Agriculture (REACCH PNA) is a five-year USDA/NIFA-funded coordinated agriculture project to examine the sustainability of cereal crop production systems in the Pacific Northwest, in relationship to ongoing climate change. As part of this effort, an extensive data management system has been developed to enable researchers, students, and the public, to upload, manage, and analyze various data. The REACCH PNA data management team has developed three core systems to encompass cyberinfrastructure and data management needs: 1) the reacchpna.org portal (https://www.reacchpna.org) is the entry point for all public and secure information, with secure access by REACCH PNA members for data analysis, uploading, and informational review; 2) the REACCH PNA Data Repository is a replicated, redundant database server environment that allows for file and database storage and access to all core data; and 3) the REACCH PNA Libraries which are functional groupings of data for REACCH PNA members and the public, based on their access level. These libraries are accessible thru our https://www.reacchpna.org portal. The developed system is structured in a virtual server environment (data, applications, web) that includes a geospatial database/geospatial web server for web mapping services (ArcGIS Server), use of ESRI's Geoportal Server for data discovery and metadata management (under the ISO 19115-2 standard), Thematic Realtime Environmental Distributed Data Services (THREDDS) for data cataloging, and Interactive Python notebook server (IPython) technology for data analysis. REACCH systems are housed and maintained by the Northwest Knowledge Network project (www.northwestknowledge.net), which provides data management services to support research. Initial project data harvesting and meta-tagging efforts have resulted in the interrogation and loading of over 10 terabytes of climate model output, regional entomological data, agricultural and atmospheric information, as well as imagery, publications, videos, and other soft content. In addition, the outlined data management approach has focused on the integration and interconnection of hard data (raw data output) with associated publications, presentations, or other narrative documentation - through metadata lineage associations. This harvest-and-consume data management methodology could additionally be applied to other research team environments that involve large and divergent data.

Low Frequency Modulation of Extreme Temperature Regimes in a Changing Climate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Black, Robert X.

2014-11-24

The project examines long-term changes in extreme temperature episodes (ETE) associated with planetary climate modes (PCMs) in both the real atmospheric and climate model simulations. The focus is on cold air outbreaks (CAOs) and warm waves (WWs) occurring over the continental US during the past 60 winters. No significant long-term trends in either WWs or CAOs are observed over the US. The annual frequency of CAOs is affected by the (i) North Atlantic Oscillation (NAO) over the Southeast US and (ii) Pacific–North American (PNA) pattern over the Northwest US. WW frequency is influenced by the (i) NAO over the easternmore » US and (ii) combined influence of PNA, Pacific decadal oscillation (PDO), and ENSO over the southern US. The collective influence of PCMs accounts for as much as 50% of the regional variability in ETE frequency. During CAO (WW) events occurring over the southeast US, there are low (high) pressure anomalies at higher atmospheric levels over the southeast US with oppositely-signed pressure anomalies in the lower atmosphere over the central US. These patterns lead to anomalous northerly (for CAOs) or southerly (for WWs) flow into the southeast leading to cold or warm surface air temperature anomalies, respectively. One distinction is that CAOs involve substantial air mass transport while WW formation is more local in nature. The primary differences among event categories are in the origin and nature of the pressure anomaly features linked to ETE onset. In some cases, PCMs help to provide a favorable environment for event onset. Heat budget analyses indicate that latitudinal transport in the lower atmosphere is the main contributor to regional cooling during CAO onset. This is partly offset by adiabatic warming associated with subsiding air. Additional diagnoses reveal that this latitudinal transport is partly due to the remote physical influence of a shallow cold pool of air trapped along the east side of the Rocky Mountains. ETE and PCM behavior is also studied in (CMIP5) climate model simulations. Although the climate models considered are able to represent the overall behavior of ETEs, the frequency of WWs (CAOs) is too high (low) in many models. While all models qualitatively replicate the overall structure of the PNA pattern, a small minority of models fails to properly simulate the NAO pattern. Model shortcomings in representing the NAO and PNA patterns have important consequences for simulating associated regional variability in surface air temperature and storm track behavior. The influence of PCMs on ETEs is underestimated in most CMIP5 models. In particular, none of the models are able to accurately simulate observed linkages between ETEs and the PDO, due to a gross misrepresentation of the PDO pattern in most models. Our results indicate that predictions of future CAO and WW behavior are currently limited by the ability of climate models to accurately represent PCM characteristics. Our study also considers the behavior of PCMs known as annular modes. It is determined that north-south movements in the stratospheric jet stream (related to the Polar Annular Mode) result in long-lasting impacts upon surface weather conditions including regional air temperature anomalies. The structure and dynamics of the stratospheric northern annular mode (or SNAM, related to changes in the strength of the stratospheric jet stream) was studied in CMIP5 models. In models with poorly-resolved stratospheres, the amplitude of SNAM at stratospheric altitudes is typically too weak, consistent with weaker stratospheric jet variability. However, this distinction does not carry over to the associated tropospheric signature of SNAM. A regional analysis illustrates that most CMIP5 models (regardless of whether the stratosphere is well-resolved) have anomalously weak and eastward shifted (compared to observed SNAM events) storm track and sea level pressure anomaly patterns during SNAM events. Analyses of stratosphere–troposphere coupling reveal that large-scale wave activity in the stratosphere is anomalously weak in CMIP5 models having poorly-resolved stratospheres, due to correspondingly weak upward propagation of wave activity from the troposphere. This suggests that such models have anomalously weak stratosphere-troposphere coupling in association with SNAM events. Paradoxically, however, there is little apparent impact upon the attendant tropospheric variability.« less

The Spatiotemporal Structure of 20th Century Climate Variations in Observations and Reanalyses. Part 2; Pacific Pan-Decadal Variability

NASA Technical Reports Server (NTRS)

Chen, Junye; DelGenio, Anthony D.; Carlson, Barbara E.; Bosilovich, Michael G.

2007-01-01

The dominant interannual El Nino-Southern Oscillation phenomenon (ENSO) and the short length of climate observation records make it difficult to study long-term climate variations in the spatiotemporal domain. Based on the fact that the ENS0 signal spreads to remote regions and induces delayed climate variation through atmospheric teleconnections, we develop an ENSO-removal method through which the ENS0 signal can be approximately removed at the grid box level from the spatiotemporal field of a climate parameter. After this signal is removed, long-term climate variations, namely, the global warming trend (GW) and the Pacific pan-decadal variability (PDV), are isolated at middle and low latitudes in the climate parameter fields from observed and reanalyses datasets. In this study, we show that one of several PDV interdecadal regime shifts occurred during the 1990s. This significant change in the Pacific basin is comparable but opposite in phase to the 1976 climate regime shift, which results persisting warming in the central-eastern Pacific, and cooling in the North and South Pacific. The 1990s PDV regime shift is consistent with observed changes in ocean biosphere and ocean circulation. A comprehensive picture of PDV as manifested in the troposphere and at the surface is described. In general, the PDV spatial patterns in different parameter fields share some similarities with the patterns associated with ENSO, but important differences exist. First, the PDV atmospheric circulation pattern is shifted westward by about 20deg and its zonal extent is limited to approx.60deg compared to approx.110deg for ENS0 pattern. The westward shift of the PDV wave train produces a different, more west-east oriented, North American teleconnection pattern. The lack of a strong PDV surface temperature (ST) signal in the western equatorial Pacific and the relatively strong ST signal in the subtropical regions are consistent with an atmospheric overturning circulation response that differs from the one associated with ENSO.

DNA detection using water-soluble conjugated polymers and peptide nucleic acid probes

PubMed Central

Gaylord, Brent S.; Heeger, Alan J.; Bazan, Guillermo C.

2002-01-01

The light-harvesting properties of cationic conjugated polymers are used to sensitize the emission of a dye on a specific peptide nucleic acid (PNA) sequence for the purpose of homogeneous, “real-time” DNA detection. Signal transduction is controlled by hybridization of the neutral PNA probe and the negative DNA target. Electrostatic interactions bring the hybrid complex and cationic polymer within distances required for Förster energy transfer. Conjugated polymer excitation provides fluorescein emission >25 times higher than that obtained by exciting the dye, allowing detection of target DNA at concentrations of 10 pM with a standard fluorometer. A simple and highly sensitive assay with optical amplification that uses the improved hybridization behavior of PNA/DNA complexes is thus demonstrated. PMID:12167673

The role of external forcing and Pacific trade winds in recent changes of the global climate system

NASA Astrophysics Data System (ADS)

Friedman, Andrew; Gastineau, Guillaume; Khodri, Myriam

2017-04-01

The Pacific trade winds experienced an unprecedented strengthening since the mid 1990s. Several studies have proposed that the increased Pacific trade winds were associated with the reduced rate of global mean surface temperature warming in the first decade of the 21st century, as well as far-reaching atmospheric teleconnections. We designed a set of ensemble partial coupling experiments using the IPSL-CM5A-LR coupled model that allow us to cleanly distinguish the influence of Pacific trade wind variability from that of external forcing over the past few decades. In this study, we quantify the respective impacts of these processes on surface temperature, ocean heat content, and atmospheric teleconnections. We designed two ensembles of coupled simulations using partial coupling with the IPSL-CM5A-LR model to separate the Pacific internal variability and that of external radiative forcing. We prescribe surface wind stress in the tropical Pacific (20°S to 20°N) from 1979-2014 in two ensembles of 30 members each: (1) Prescribed climatological model wind stress, which allows us to estimate the influence of external radiative forcing in the absence of variability within the Pacific Ocean. (2) Wind stress anomalies from ERA-Interim reanalysis added to the model wind stress climatology, which accounts for the effects of both external radiative forcing and the wind stress variability. We find that the observed wind stress anomalies account for the pattern of eastern tropical Pacific cooling when compared to the climatology experiment, so that it resembles the observed trends from 1992-2011. The tropical Pacific shows dominant heat uptake in the western Pacific above the 20°C isotherm, which contributed to slow the warming of tropical SST during the 2000s. The trade wind increase is associated with a strengthening of the Pacific Walker circulation, and zonal shifts in tropical rainfall. Despite tropical SST biases which affect the response of tropical rainfall and the location of deep convection, the wind stress anomaly forcing effectively simulates the wave train pattern emanating from the tropical Pacific, and associated extratropical teleconnections such as a weakening of the Aleutian Low and drought in North America.

Role of Equatorial Pacific SST Anomalies in Precipitation over Western Americas

NASA Astrophysics Data System (ADS)

Jong, B. T.; Ting, M.; Seager, R.; Henderson, N.; Lee, D.

2017-12-01

El Niño, as the prime source of seasonal to interannual climate predictability, could impose impacts on the Americas from tropical to mid-latitude regions. The teleconnection patterns are sensitive to the longitudinal location of the maximum tropical sea surface temperature anomalies (SSTA). Meanwhile, slight differences in the location and configuration of the anomalous atmospheric circulations could differentiate between a wet and dry season regionally. For example, the 2015/16 strong El Niño event did not bring excessive precipitation to California despite expectations based on observational and model-based analyses. Whether the westward shift in the tropical SSTA pattern played a key role during this event is examined. We conduct two SSTA-forced experimental runs in three NCAR GCMs (CCM3, CAM4, and CAM5): one forced by the observed February-March-April 2016 SSTA and the other forced by the model-ensemble mean forecast FMA 2016 SSTA from the North America Multi-Model Ensemble. The observed SSTAs, compared to the forecast SSTAs, are colder in the central-eastern tropical Pacific and slightly warmer in the westernmost tropical Pacific. In response, all three models have a weaker and westward shifted low-pressure anomaly over the North Pacific and west coast of North America when the observed SSTA is prescribed. As the result, northern California is either about the same or drier in the observed SSTA runs than in the forecast SSTA runs. However, the precipitation over southern California responds differently across models. One of the possible explanations is that in CCM3 the teleconnections respond mainly to the SSTA differences in the eastern tropical Pacific; while in CAM4 and CAM5, the teleconnections are also sensitive to the small SSTA differences in the western tropical Pacific. The results suggest that the tropical SSTA differences matter for atmospheric circulations and precipitation over western Americas even though models disagree on the details of the circulation responses and subsequently the sign of regional precipitation responses. Further work on the sensitivity of circulations and precipitation to the tropical Pacific SSTA forcing will be conducted to improve the prediction of precipitation over western Americas.

A multimodel approach to interannual and seasonal prediction of Danube discharge anomalies

NASA Astrophysics Data System (ADS)

Rimbu, Norel; Ionita, Monica; Patrut, Simona; Dima, Mihai

2010-05-01

Interannual and seasonal predictability of Danube river discharge is investigated using three model types: 1) time series models 2) linear regression models of discharge with large-scale climate mode indices and 3) models based on stable teleconnections. All models are calibrated using discharge and climatic data for the period 1901-1977 and validated for the period 1978-2008 . Various time series models, like autoregressive (AR), moving average (MA), autoregressive and moving average (ARMA) or singular spectrum analysis and autoregressive moving average (SSA+ARMA) models have been calibrated and their skills evaluated. The best results were obtained using SSA+ARMA models. SSA+ARMA models proved to have the highest forecast skill also for other European rivers (Gamiz-Fortis et al. 2008). Multiple linear regression models using large-scale climatic mode indices as predictors have a higher forecast skill than the time series models. The best predictors for Danube discharge are the North Atlantic Oscillation (NAO) and the East Atlantic/Western Russia patterns during winter and spring. Other patterns, like Polar/Eurasian or Tropical Northern Hemisphere (TNH) are good predictors for summer and autumn discharge. Based on stable teleconnection approach (Ionita et al. 2008) we construct prediction models through a combination of sea surface temperature (SST), temperature (T) and precipitation (PP) from the regions where discharge and SST, T and PP variations are stable correlated. Forecast skills of these models are higher than forecast skills of the time series and multiple regression models. The models calibrated and validated in our study can be used for operational prediction of interannual and seasonal Danube discharge anomalies. References Gamiz-Fortis, S., D. Pozo-Vazquez, R.M. Trigo, and Y. Castro-Diez, Quantifying the predictability of winter river flow in Iberia. Part I: intearannual predictability. J. Climate, 2484-2501, 2008. Gamiz-Fortis, S., D. Pozo-Vazquez, R.M. Trigo, and Y. Castro-Diez, Quantifying the predictability of winter river flow in Iberia. Part II: seasonal predictability. J. Climate, 2503-2518, 2008. Ionita, M., G. Lohmann, and N. Rimbu, Prediction of spring Elbe river discharge based on stable teleconnections with global temperature and precipitation. J. Climate. 6215-6226, 2008.

Tying Variability in Summertime North American Extreme Weather Regimes to the Boreal Summer Intraseasonal Oscillation

NASA Astrophysics Data System (ADS)

Jenney, A. M.; Randall, D. A.

2017-12-01

Tropical intraseasonal oscillations are known to be a source of extratropical variability. We show that subseasonal variability in observed North American epidemiologically significant regional extreme weather regimes is teleconnected to the boreal summer intraseasonal oscillation (BSISO)—a complex tropical weather system that is active during the northern summer and has a 30-50 day timescale. The dynamics of the teleconnection are examined. We also find that interannual variability of the tropical mean-state can modulate the teleconnection. Our results suggest that the BSISO may enable subseasonal to seasonal predictions of North American summertime weather extremes.

Parabolic northern-hemisphere river flow teleconnections to El Niño-Southern Oscillation and the Arctic Oscillation

NASA Astrophysics Data System (ADS)

Fleming, S. W.; Dahlke, H. E.

2014-10-01

It is almost universally assumed in statistical hydroclimatology that relationships between large-scale climate indices and local-scale hydrometeorological responses, though possibly nonlinear, are monotonic. However, recent work suggests that northern-hemisphere atmospheric teleconnections to El Niño-Southern Oscillation (ENSO) and the Arctic Oscillation can be parabolic. The effect has recently been explicitly confirmed in hydrologic responses, though associations are complicated by land surface characteristics and processes, and investigation of water resource implications has been limited to date. Here, we apply an Akaike Information Criterion-based polynomial selection approach to investigate annual flow volume teleconnections for 42 of the northern hemisphere’s largest ocean-reaching rivers. Though we find a rich diversity of responses, parabolic relationships are formally consistent with the data for almost half the rivers, and the optimal model for eight. These highly nonlinear water supply teleconnections could radically alter the standard conceptual model of how water resources respond to climatic variability. For example, the Sacramento river in drought-ridden California exhibits no significant monotonic ENSO teleconnection but a 0.92 probability of a quadratic relationship, reducing mean predictive error by up to 65% and suggesting greater opportunity for climate index-based water supply forecasts than previously appreciated.

Maternal testosterone exposure increases anxiety-like behavior and impacts the limbic system in the offspring.

PubMed

Hu, Min; Richard, Jennifer Elise; Maliqueo, Manuel; Kokosar, Milana; Fornes, Romina; Benrick, Anna; Jansson, Thomas; Ohlsson, Claes; Wu, Xiaoke; Skibicka, Karolina Patrycja; Stener-Victorin, Elisabet

2015-11-17

During pregnancy, women with polycystic ovary syndrome (PCOS) display high circulating androgen levels that may affect the fetus and increase the risk of mood disorders in offspring. This study investigated whether maternal androgen excess causes anxiety-like behavior in offspring mimicking anxiety disorders in PCOS. The PCOS phenotype was induced in rats following prenatal androgen (PNA) exposure. PNA offspring displayed anxiety-like behavior in the elevated plus maze, which was reversed by flutamide [androgen receptor (AR) blocker] and tamoxifen [selective estrogen receptor (ER) modulator]. Circulating sex steroids did not differ between groups at adult age. The expression of serotonergic and GABAergic genes associated with emotional regulation in the amygdala was consistent with anxiety-like behavior in female, and partly in male PNA offspring. Furthermore, AR expression in amygdala was reduced in female PNA offspring and also in females exposed to testosterone in adult age. To determine whether AR activation in amygdala affects anxiety-like behavior, female rats were given testosterone microinjections into amygdala, which resulted in anxiety-like behavior. Together, these data describe the anxiety-like behavior in PNA offspring and adult females with androgen excess, an impact that seems to occur during fetal life, and is mediated via AR in amygdala, together with changes in ERα, serotonergic, and GABAergic genes in amygdala and hippocampus. The anxiety-like behavior following testosterone microinjections into amygdala demonstrates a key role for AR activation in this brain area. These results suggest that maternal androgen excess may underpin the risk of developing anxiety disorders in daughters and sons of PCOS mothers.

Prenatal androgen excess programs metabolic derangements in pubertal female rats.

PubMed

Yan, Xiaonan; Dai, Xiaonan; Wang, Jing; Zhao, Nannan; Cui, Yugui; Liu, Jiayin

2013-04-01

Owing to the heterogeneity in the clinical symptoms of polycystic ovary syndrome (PCOS), the early pathophysiological mechanisms of PCOS remain unclear. Clinical, experimental, and genetic evidence supports an interaction between genetic susceptibility and the influence of maternal environment in the pathogenesis of PCOS. To determine whether prenatal androgen exposure induced PCOS-related metabolic derangements during pubertal development, we administrated 5α-dihydrotestosterone (DHT) in pregnant rats and observed their female offspring from postnatal 4 to 8 weeks. The prenatally androgenized (PNA) rats exhibited more numerous total follicles, cystic follicles, and atretic follicles than the controls. Fasting glucose, insulin, leptin levels, and homeostatic model assessment for insulin resistance were elevated in the PNA rats at the age of 5-8 weeks. Following intraperitoneal glucose tolerance tests, glucose and insulin levels did not differ between two groups; however, the PNA rats showed significantly higher 30- and 60-min glucose levels than the controls after insulin stimulation during 5-8 weeks. In addition, prenatal DHT treatment significantly decreased insulin-stimulated phosphorylation of AKT in the skeletal muscles of 6-week-old PNA rats. The abundance of IR substrate 1 (IRS1) and IRS2 was decreased in the skeletal muscles and liver after stimulation with insulin in the PNA group, whereas phosphorylation of insulin-signaling proteins was unaltered in the adipose tissue. These findings validate the contribution of prenatal androgen excess to metabolic derangements in pubertal female rats, and the impaired insulin signaling through IRS and AKT may result in the peripheral insulin resistance during pubertal development.

Fluorescence in situ Hybridization method using Peptide Nucleic Acid probes for rapid detection of Lactobacillus and Gardnerella spp.

PubMed Central

2013-01-01

Background Bacterial vaginosis (BV) is a common vaginal infection occurring in women of reproductive age. It is widely accepted that the microbial switch from normal microflora to BV is characterized by a decrease in vaginal colonization by Lactobacillus species together with an increase of Gardnerella vaginalis and other anaerobes. Our goal was to develop and optimize a novel Peptide Nucleic Acid (PNA) Fluorescence in situ Hybridization assay (PNA FISH) for the detection of Lactobacillus spp. and G. vaginalis in mixed samples. Results Therefore, we evaluated and validated two specific PNA probes by using 36 representative Lactobacillus strains, 22 representative G. vaginalis strains and 27 other taxonomically related or pathogenic bacterial strains commonly found in vaginal samples. The probes were also tested at different concentrations of G. vaginalis and Lactobacillus species in vitro, in the presence of a HeLa cell line. Specificity and sensitivity of the PNA probes were found to be 98.0% (95% confidence interval (CI), from 87.8 to 99.9%) and 100% (95% CI, from 88.0 to 100.0%), for Lactobacillus spp.; and 100% (95% CI, from 92.8 to 100%) and 100% (95% CI, from 81.5 to 100.0%) for G. vaginalis. Moreover, the probes were evaluated in mixed samples mimicking women with BV or normal vaginal microflora, demonstrating efficiency and applicability of our PNA FISH. Conclusions This quick method accurately detects Lactobacillus spp. and G. vaginalis species in mixed samples, thus enabling efficient evaluation of the two bacterial groups, most frequently encountered in the vagina. PMID:23586331

Peptide nucleic acid probe-based fluorescence melting curve analysis for rapid screening of common JAK2, MPL, and CALR mutations.

PubMed

Park, Joonhong; Song, Minsik; Jang, Woori; Chae, Hyojin; Lee, Gun Dong; Kim, KyungTak; Park, Heekyung; Kim, Myungshin; Kim, Yonggoo

2017-02-01

We developed and evaluated the feasibility of peptide nucleic acid (PNA)-based fluorescence melting curve analysis (FMCA) to detect common mutations in myeloproliferative neoplasms (MPNs). We have set up two separate reactions of PNA-based FMCA: JAK2 V617F &CALR p.Leu367fs*46 (set A) and MPL W515L/K &CALR p.Lys385fs*47 (set B). Clinical usefulness was validated with allele-specific real-time PCR, fragment analysis, Sanger sequencing in 57 BCR-ABL1-negative MPNs. The limit of detection (LOD) of PNA-based FMCA was approximately 10% for each mutation and interference reactions using mixtures of different mutations were not observed. Non-specific amplification was not observed in normal control. PNA-based FMCA was able to detect all JAK2 V617F (n=20), CALR p.Leu367fs*46 (n=10) and p.Lys385fs*47 (n=8). Three of six MPL mutations were detected except three samples with low mutant concentration in out of LOD. JAK2 exon 12 mutations (n=7) were negative without influencing V617F results. Among six variant CALR exon 9 mutations, two were detected by this method owing to invading of probe binding site. PNA-based FMCA for detecting common JAK2, MPL, and CALR mutations is a rapid, simple, and sensitive technique in BCR-ABL1-negative MPNs with >10% mutant allele at the time of initial diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Elevated androstenedione in young adult but not early adolescent prenatally androgenized female rats.

PubMed

Shah, Ami B; Nivar, Isaac; Speelman, Diana L

2018-01-01

Elevated testosterone (T) is routinely reported as a marker of hyperandrogenemia in rodent models for polycystic ovary syndrome (PCOS). In women with PCOS, elevated serum androstenedione (A4) is associated with more severe phenotypes, including a positive correlation with serum T, DHEAS, free androgen index (FAI), LH, and LH/FSH ratio. Furthermore, A4, along with calculated free T and FAI, was identified as one of the best predictors of PCOS in adult women of all ages (18 to > 50 y). The objective of this study was to investigate serum A4 levels in early adolescent and young adult prenatally androgenized (PNA) female rats, a model for PCOS. Pregnant rats were injected with 5 mg T daily during gestational days 16-19 (PNA rats, experimental group) or an equal volume of vehicle (control group). Female offspring of both groups had tail vein blood drawn for serum analysis at 8 and 16 weeks of age. ELISAs were used to quantify serum A4 and T levels. Serum A4 and T were elevated in 16-week-old PNA rats compared to controls. There was no significant difference in either hormone at 8 weeks of age. The PNA rats demonstrated elevated serum A4 and T in young adulthood, as has been observed in women with PCOS, further validating this as a model for PCOS and underscoring the importance of serum A4 elevation as a parameter inherent to PCOS and a rodent model for the disorder. Significant A4 elevation develops between early adolescence and early adulthood in this PNA rat model.

Peptide Nucleic Acid Knockdown and Intra-host Cell Complementation of Ehrlichia Type IV Secretion System Effector.

PubMed

Sharma, Pratibha; Teymournejad, Omid; Rikihisa, Yasuko

2017-01-01

Survival of Ehrlichia chaffeensis depends on obligatory intracellular infection. One of the barriers to E. chaffeensis research progress has been the inability, using conventional techniques, to generate knock-out mutants for genes essential for intracellular infection. This study examined the use of Peptide Nucleic Acids (PNAs) technology to interrupt type IV secretion system (T4SS) effector protein expression in E. chaffeensis followed by intracellular complementation of the effector to determine its requirement for infection. Successful E. chaffeensis infection depends on the E. chaffeensis -specific T4SS protein effector, ehrlichial translocated factor-1 (Etf-1), which induces Rab5-regulated autophagy to provide host cytosolic nutrients required for E. chaffeensis proliferation. Etf-1 is also imported by host cell mitochondria where it inhibits host cell apoptosis to prolong its infection. We designed a PNA specific to Etf-1 and showed that the PNA bound to the target region of single-stranded Etf-1 RNA using a competitive binding assay. Electroporation of E. chaffeensis with this PNA significantly reduced Etf-1 mRNA and protein, and the bacteria's ability to induce host cell autophagy and infect host cells. Etf-1 PNA-mediated inhibition of ehrlichial Etf-1 expression and E. chaffeensis infection could be intracellularly trans-complemented by ectopic expression of Etf-1-GFP in host cells. These data affirmed the critical role of bacterial T4SS effector in host cell autophagy and E. chaffeensis infection, and demonstrated the use of PNA to analyze the gene functions of obligate intracellular bacteria.

Peptide Nucleic Acid Knockdown and Intra-host Cell Complementation of Ehrlichia Type IV Secretion System Effector

PubMed Central

Sharma, Pratibha; Teymournejad, Omid; Rikihisa, Yasuko

2017-01-01

Survival of Ehrlichia chaffeensis depends on obligatory intracellular infection. One of the barriers to E. chaffeensis research progress has been the inability, using conventional techniques, to generate knock-out mutants for genes essential for intracellular infection. This study examined the use of Peptide Nucleic Acids (PNAs) technology to interrupt type IV secretion system (T4SS) effector protein expression in E. chaffeensis followed by intracellular complementation of the effector to determine its requirement for infection. Successful E. chaffeensis infection depends on the E. chaffeensis-specific T4SS protein effector, ehrlichial translocated factor-1 (Etf-1), which induces Rab5-regulated autophagy to provide host cytosolic nutrients required for E. chaffeensis proliferation. Etf-1 is also imported by host cell mitochondria where it inhibits host cell apoptosis to prolong its infection. We designed a PNA specific to Etf-1 and showed that the PNA bound to the target region of single-stranded Etf-1 RNA using a competitive binding assay. Electroporation of E. chaffeensis with this PNA significantly reduced Etf-1 mRNA and protein, and the bacteria's ability to induce host cell autophagy and infect host cells. Etf-1 PNA-mediated inhibition of ehrlichial Etf-1 expression and E. chaffeensis infection could be intracellularly trans-complemented by ectopic expression of Etf-1-GFP in host cells. These data affirmed the critical role of bacterial T4SS effector in host cell autophagy and E. chaffeensis infection, and demonstrated the use of PNA to analyze the gene functions of obligate intracellular bacteria. PMID:28638803

Maternal testosterone exposure increases anxiety-like behavior and impacts the limbic system in the offspring

PubMed Central

Hu, Min; Richard, Jennifer Elise; Maliqueo, Manuel; Kokosar, Milana; Fornes, Romina; Benrick, Anna; Jansson, Thomas; Ohlsson, Claes; Wu, Xiaoke; Skibicka, Karolina Patrycja; Stener-Victorin, Elisabet

2015-01-01

During pregnancy, women with polycystic ovary syndrome (PCOS) display high circulating androgen levels that may affect the fetus and increase the risk of mood disorders in offspring. This study investigated whether maternal androgen excess causes anxiety-like behavior in offspring mimicking anxiety disorders in PCOS. The PCOS phenotype was induced in rats following prenatal androgen (PNA) exposure. PNA offspring displayed anxiety-like behavior in the elevated plus maze, which was reversed by flutamide [androgen receptor (AR) blocker] and tamoxifen [selective estrogen receptor (ER) modulator]. Circulating sex steroids did not differ between groups at adult age. The expression of serotonergic and GABAergic genes associated with emotional regulation in the amygdala was consistent with anxiety-like behavior in female, and partly in male PNA offspring. Furthermore, AR expression in amygdala was reduced in female PNA offspring and also in females exposed to testosterone in adult age. To determine whether AR activation in amygdala affects anxiety-like behavior, female rats were given testosterone microinjections into amygdala, which resulted in anxiety-like behavior. Together, these data describe the anxiety-like behavior in PNA offspring and adult females with androgen excess, an impact that seems to occur during fetal life, and is mediated via AR in amygdala, together with changes in ERα, serotonergic, and GABAergic genes in amygdala and hippocampus. The anxiety-like behavior following testosterone microinjections into amygdala demonstrates a key role for AR activation in this brain area. These results suggest that maternal androgen excess may underpin the risk of developing anxiety disorders in daughters and sons of PCOS mothers. PMID:26578781

The variability of temperature and precipitation over Korean Peninsula induced by off-equatorial western Pacific precipitation during boreal summer

NASA Astrophysics Data System (ADS)

Jeong, Yerim; Ham, Yoo-Geun

2016-04-01

The convection activity and variability are active in Tropic-subtropic area because of equatorial warm pool. The variability's impacts on not only subtropic also mid-latitude. The impact effects on through teleconnection between equatorial and mid-latitude like Pacific-Japan(PJ) pattern. In this paper, two groups are divided based on PJ pattern and JJA Korean precipitation for the analysis that Korean precipitation is affected by PJ pattern. 'PJ+NegKorpr' is indicated when PJ pattern occur that JJA(Jun-July_August) Korean precipitation has negative value. In this case, positive precipitation in subtropic is expanded to central Pacific. And the positive precipitation's pattern is increasing toward north. Because, the subtropical south-eastly wind is forming subtropical precipitation's pattern through cold Kelvin wave is expanding eastward. Cold Kelvin wave is because of Indian negative SST. Also, Korea has negative moisture advection and north-eastly is the role that is moving high-latitude's cold and dry air to Korea. So strong high pressure is formed in Korea. The strong high pressure involves that short wave energy is increasing on surface. As a result, The surface temperature is increased on Korea. But the other case, that 'PJ_Only' case, is indicated when PJ pattern occur and JJA Korean precipitation doesn't have negative value over significant level. The subtropic precipitation's pattern in 'PJ_Only' shows precipitation is confined in western Pacific and expended northward to 25°N near 130°E. And tail of precipitation is toward equatorial(south-eastward). Also, Korean a little positive moisture advection and south-westly is the role that is moving low-latitude's warm and wet air to Korea. So weak high pressure is formed in Korea. The weak high pressure influence amount of short wave energy, so Korean surface temperature is lower. In addition, the case of 'PJ_Only' and Pacific Decal Oscillation(PDO) are occur at the same time has negative impact in Korea temperature through subtropical cyclone and positive PDO. The positive PDO is the role that negative temperature in Korea. So, Korean temperature confined lower by subtropical cyclone and positive PDO. In summary, the relation between PJ pattern and JJA Korean temperature and precipitation depends on subtropical precipitation's pattern. And The subtropical precipitation is effected by Indian SST and PDO's teleconnection.

Plasma concentrations of carbohydrates and sugar alcohols in term newborns after milk feeding.

PubMed

Brown, Laura D; Cavalli, Claudio; Harwood, Jeri E F; Casadei, Annachiara; Teng, Cecilia C; Traggiai, Cristina; Serra, Giovanni; Bevilacqua, Giulio; Battaglia, Frederick C

2008-08-01

Nonglucose carbohydrates such as galactose, mannose, and inositol play a clinically important role in fetal and neonatal nutrition, though little is known about their metabolism in the neonate. The aim of this study was to determine whether postprandial changes in plasma carbohydrate and sugar alcohol concentrations are affected by clinical variables such as postnatal age (PNA), milk type, feeding volume, or feeding duration in term newborns. Neonates (n = 26) taking intermittent enteral feedings were enrolled. Blood samples were obtained at baseline (immediately before the start of a feeding) and at 2-3 subsequent time points up to 110 min. Postprandial rise was only observed for plasma glucose concentrations [Glu] and plasma galactose concentrations [Gal] and clinical variables did not predict this change. Despite equimolar delivery in milk, the median of [Glu] rise minus [Gal] rise from baseline to second postprandial plasma sample was 674 microM (-38, 3333 microM; p < 0.0001), reflecting efficient hepatic first-pass metabolism of galactose. A significant PNA effect on [Gal] was observed such that for each day PNA there was an 18% decrease in [Gal] (p = 0.03). [Gal] are a function of PNA, suggesting maintenance of a significant ductus venosus shunt in term infants.

High affinity γPNA sandwich hybridization assay for rapid detection of short nucleic acid targets with single mismatch discrimination.

PubMed

Goldman, Johnathan M; Zhang, Li Ang; Manna, Arunava; Armitage, Bruce A; Ly, Danith H; Schneider, James W

2013-07-08

Hybridization analysis of short DNA and RNA targets presents many challenges for detection. The commonly employed sandwich hybridization approach cannot be implemented for these short targets due to insufficient probe-target binding strengths for unmodified DNA probes. Here, we present a method capable of rapid and stable sandwich hybridization detection for 22 nucleotide DNA and RNA targets. Stable hybridization is achieved using an n-alkylated, polyethylene glycol γ-carbon modified peptide nucleic acid (γPNA) amphiphile. The γPNA's exceptionally high affinity enables stable hybridization of a second DNA-based probe to the remaining bases of the short target. Upon hybridization of both probes, an electrophoretic mobility shift is measured via interaction of the n-alkane modification on the γPNA with capillary electrophoresis running buffer containing nonionic surfactant micelles. We find that sandwich hybridization of both probes is stable under multiple binding configurations and demonstrate single base mismatch discrimination. The binding strength of both probes is also stabilized via coaxial stacking on adjacent hybridization to targets. We conclude with a discussion on the implementation of the proposed sandwich hybridization assay as a high-throughput microRNA detection method.

Parasympathetic neural control of canine tracheal smooth muscle.

PubMed

Kobayashi, Ichiro; Kondo, Tetsuri; Hayama, Naoki; Tazaki, Gen

2004-12-01

The middle segment of the trachea is innervated by the recurrent laryngeal and pararecurrent nerves. This study determined the pathway that mediated descending commands to the tracheal smooth muscle. Animals used were seven paralyzed and tracheostomized dogs. Tracheal contraction induced either by apnea, mechanical stimulation of the tracheal bifurcation or hypercapnia was always composed of tonic and rhythmic components. The rhythmic contraction developed in synchrony with rhythmic bursts on phrenic nerve activity (PNA). The respiratory-related bursts were also observed on the recurrent laryngeal nerve activity (RNA) and pararecurrent nerve activity (ParaRNA). During apnea there was no tonic activity neither on RNA or PNA, whereas ParaRNA had both tonic and rhythmic activities. Bursts on RNA preceded to correspondent PNA-bursts by 90+/-13 ms. In contrast, ParaRNA-burst always developed later than PNA-burst and it started at almost the same time as that of tracheal rhythmic contraction. During mechanical stimulation of the trachea or CO2-loading, though RNA did not include tonic component, ParaRNA had tonic activity during tracheal tonic contraction. These findings suggested that rhythmic and tonic contractions of the trachea were mediated through the pararecurrent nerve but not through the recurrent laryngeal nerve.

Atmospheric Teleconnection over Eurasia Induced by Aerosol Radiative Forcing During Boreal Spring

NASA Technical Reports Server (NTRS)

Kim, Maeng-Ki; Lau, K. M.; Chin, Mian; Kim, Kyu-Myong; Sud, Y. C.; Walker, Greg K.

2005-01-01

The direct effects of aerosols on global and regional climate during boreal spring are investigated based on simulations using the NASA Global Modeling and Assimilation Office (GMAO) finite-volume general circulation model (fvGCM) with Microphyics of clouds in Relaxed Arakawa Schubert Scheme (McRAS). The aerosol loading are prescribed from three-dimensional monthly distribution of tropospheric aerosols viz., sulfate, black carbon, organic carbon, soil dust, and sea salt from output of the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The aerosol extinction coefficient, single scattering albedo, and asymmetric factor are computed as wavelength-dependent radiative forcing in the radiative transfer scheme of the fvGCM, and as a function of the aerosol loading and ambient relative humidity. We find that anomalous atmospheric heat sources induced by absorbing aerosols (dust and black carbon) excites a planetary scale teleconnection pattern in sea level pressure, temperature and geopotential height spanning North Africa through Eurasia to the North Pacific. Surface cooling due to direct effects of aerosols is found in the vicinity and downstream of the aerosol source regions, i.e., South Asia, East Asia, and northern and western Africa. Additionally, atmospheric heating is found in regions with large loading of dust (over Northern Africa, and Middle East), and black carbon (over South-East Asia). Paradoxically, the most pronounced feature in aerosol-induced surface temperature is an east-west dipole anomaly with strong cooling over the Caspian Sea, and warming over central and northeastern Asia, where aerosol concentration are low. Analyses of circulation anomalies show that the dipole anomaly is a part of an atmospheric teleconnection driven by atmospheric heating anomalies induced by absorbing aerosols in the source regions, but the influence was conveyed globally through barotropic energy dispersion and sustained by feedback processes associated with the regional circulations.

North American wintertime temperature anomalies: the role of El Niño diversity and differential teleconnections

NASA Astrophysics Data System (ADS)

Beyene, Mussie T.; Jain, Shaleen

2018-06-01

El Niño-Southern Oscillation (ENSO) teleconnections induced wintertime surface air temperature (SAT) anomalies over North America show inter-event variability, asymmetry, and nonlinearity. This diagnostic study appraises the assumption that ENSO-induced teleconnections are adequately characterized as symmetric shifts in the SAT probability distributions for North American locations. To this end, a new conditional quantile functional estimation approach presented here incorporates: (a) the detailed nature of location and amplitude of SST anomalies—in particular the Eastern Pacific (EP), Central Pacific (CP) ENSO events—based on its two leading principal components, and (b) over the entire range of SATs, characterize the differential sensitivity to ENSO. Statistical significance is assessed using a wild bootstrap approach. Conditional risk at upper and lower quartile SAT conditioned on archetypical ENSO states is derived. There is marked asymmetry in ENSO effects on the likelihood of upper and lower quartile winter SATs for most North American regions. CP El Niño patterns show 20-80% decrease in the likelihood of lower quartile SATs for Canada and US west coast and a 20-40% increase across southeastern US. However, the upper quartile SAT for large swathes of Canada shows no sensitivity to CP El Niño. Similarly, EP El Niño is linked to a 40-80% increase in the probability of upper quartile winter SATs for Canada and northern US and a 20% decrease for southern US and northern Mexico regions; however, little or no change in the risk of lower quartile winter temperatures for southern parts of North America. Localized estimate of ENSO-related risk are also presented.

Factors affecting the 7Be surface concentration and its extremely high occurrences over the Scandinavian Peninsula during autumn and winter.

PubMed

Ajtić, J; Brattich, E; Sarvan, D; Djurdjevic, V; Hernández-Ceballos, M A

2018-05-01

Relationships between the beryllium-7 activity concentrations in surface air and meteorological parameters (temperature, atmospheric pressure, and precipitation), teleconnection indices (Arctic Oscillation, North Atlantic Oscillation, and Scandinavian pattern) and number of sunspots are investigated using two multivariate statistical techniques: hierarchical cluster and factor analysis. The beryllium-7 surface measurements over 1995-2011, at four sampling sites located in the Scandinavian Peninsula, are obtained from the Radioactivity Environmental Monitoring Database. In all sites, the statistical analyses show that the beryllium-7 concentrations are strongly linked to temperature. Although the beryllium-7 surface concentration exhibits the well-characterised spring/summer maximum, our study shows that extremely high beryllium-7 concentrations, defined as the values exceeding the 90 th percentile in the data records for each site, also occur over the October-March period. Two types of autumn/winter extremes are distinguished: type-1 when the number of extremes in a given month is less than three, and type-2 when at least three extremes occur in a month. Factor analysis performed for these autumn/winter events shows a weaker effect of temperature and a stronger impact of the transport and production signal on the beryllium-7 concentrations. Further, the majority of the type-2 extremes are associated with a very high monthly Scandinavian teleconnection index. The type-2 extremes that occurred in January, February and March are also linked to sudden stratospheric warmings of the Arctic vortex. Our results indicate that the Scandinavian teleconnection index might be a good indicator of the meteorological conditions facilitating extremely high beryllium-7 surface concentrations over Scandinavia during autumn and winter. Copyright © 2018 Elsevier Ltd. All rights reserved.

Teleconnection Linking Asian/Pacific Monsoon Variability and Summertime Droughts and Floods Over the United States

NASA Technical Reports Server (NTRS)

Lau, K. M.; Weng, Hengyi

2000-01-01

Major droughts and floods over the U.S. continent may be related to a far field energy source in the Asian Pacific. This is illustrated by two climate patterns associated with summertime rainfall over the U.S. and large-scale circulation on interannual timescale. The first shows an opposite variation between the drought/flood over the Midwest and that over eastern and southeastern U.S., coupled to a coherent wave pattern spanning the entire East Asia-North Pacific-North America region related to the East Asian jetstream. The second shows a continental-scale drought/flood in the central U.S., coupled to a wavetrain linking Asian/Pacific monsoon region to North America.

Climate Change Amplifications of Climate-Fire Teleconnections in the Southern Hemisphere

NASA Astrophysics Data System (ADS)

Mariani, Michela; Holz, Andrés.; Veblen, Thomas T.; Williamson, Grant; Fletcher, Michael-Shawn; Bowman, David M. J. S.

2018-05-01

Recent changes in trend and variability of the main Southern Hemisphere climate modes are driven by a variety of factors, including increasing atmospheric greenhouse gases, changes in tropical sea surface temperature, and stratospheric ozone depletion and recovery. One of the most important implications for climatic change is its effect via climate teleconnections on natural ecosystems, water security, and fire variability in proximity to populated areas, thus threatening human lives and properties. Only sparse and fragmentary knowledge of relationships between teleconnections, lightning strikes, and fire is available during the observed record within the Southern Hemisphere. This constitutes a major knowledge gap for undertaking suitable management and conservation plans. Our analysis of documentary fire records from Mediterranean and temperate regions across the Southern Hemisphere reveals a critical increased strength of climate-fire teleconnections during the onset of the 21st century including a tight coupling between lightning-ignited fire occurrences, the upward trend in the Southern Annular Mode, and rising temperatures across the Southern Hemisphere.

Missing-orbital analysis on hyperpolarizability β of organic molecules. Enhancement of the off-diagonal component βzxx using multiple substitutions

NASA Astrophysics Data System (ADS)

Tomonari, Mutsumi; Ookubo, Norio; Takada, Toshikazu

1995-04-01

The first-order hyperpolarizability components, βzzz and βzxx, for C 2v molecules (the z axis being the principal axis) are analyzed after simplified sum-over-states calculations. Compared with p-nitroaniline (PNA), βzxx is three times enhanced by x-extended π conjugation realized by a bulky substrate in 9-amino-10-nitroanthracene (ANA) and by multiple substitutions in 1,5-diamino-2,4-dinitrobenzene (DDB). While ANA shows βzzz unchanged because its z-directed charge transfer (CT) is similar to PNA, DDB has a β zzz1/3 of PNA, which is reduced by two weak CTs introduced by two ortho-positioned donor-acceptor pairs on both sides of the z axis.

Influence of tropical atmospheric variability on Weddell Sea deep water convection

NASA Astrophysics Data System (ADS)

Kleppin, H.

2016-02-01

Climate reconstructions from ice core records in Greenland and Antarctica have revealed a series of abrupt climate transitions, showing a distinct relationship between northern and southern hemisphere climate during the last glacial period. The recent ice core records from West Antarctica (WAIS) point towards an atmospheric teleconnection as a possible trigger for the interhemispheric climate variability (Markle et al., 2015). An unforced simulation of the Community Climate System Model, version 4 (CCSM4) reveals Greenland warming and cooling events, caused by stochastic atmospheric forcing, that resemble Dansgaard-Oeschger cycles in pattern and magnitude (Kleppin et al., 2015). Anti-phased temperature changes in the Southern Hemisphere are small in magnitude and have a spatially varying pattern. We argue that both north and south high latitude climate variability is triggered by changes in tropical atmospheric deep convection in the western tropical Pacific. The atmospheric wave guide provides a fast communication pathway connecting the deep tropics and the polar regions. In the Southern Hemisphere this is manifested as a distinct pressure pattern over West Antarctica. These altered atmospheric surface conditions over the convective region can lead to destabilization of the water column and thus to convective overturning in the Weddell Sea. However, opposed to what is seen in the Northern Hemisphere no centennial scale variability can establish, due to the absence of a strong feedback mechanism between ocean, atmosphere and sea ice. Kleppin, H., Jochum, M., Otto-Bliesner, B., Shields, C. A., & Yeager, S. (2015). Stochastic Atmospheric Forcing as a Cause of Greenland Climate Transitions. Journal of Climate, (2015). Markle, B. and Coauthors (2015, April). Atmospheric teleconnections between the tropics and high southern latitudes during millennial climate change. In EGU General Assembly Conference Abstracts (Vol. 17, p. 2569).

Statistical downscaling forecast of Chinese winter temperature based on the autumn SST anomalies

NASA Astrophysics Data System (ADS)

Lu, J.

2017-12-01

This study investigates the impacts of the autumn sea surface temperature anomalies (SSTA) on interannual variations of Chinese winter temperature, and discusses the potential predictability of December-January-February (DJF) 2-m air temperature anomalies (TSA) over China based on the intimate linkage between the DJF TSA and autumn SSTA. According to the Empirical Orthogonal Function (EOF) analysis, three leading EOF modes jointly account for 80% of the total TSA variances and are characterized by a homogeneous spatial pattern, a north-south seesaw and a cross structure. The first three EOFs exhibit a stable feature revealed by cross-validation, suggesting the potential predictability of the DJF TSA. The EOF1 mode is influenced by changes in the intensities of the Siberian High (SH), East Asian winter monsoon (EAWM) and East Asian Trough related to an Eurasian pattern teleconnection, which can be tracked back to September-October-November (SON) SSTA associated with two SSTA tripole patterns in the North Pacific and North Atlantic, a dipole mode in the Indian Ocean and an ENSO-like mode in the equatorial and subtropical Pacific. However, the Arctic Oscillation plays an important role in the second mode. The teleconnection connecting the atmospheric circulation anomalies in two hemispheres indicates that the configuration of global SON SSTA induces the two annular modes and causes a TSA oscillation between the northern and southern parts of China. The third mode is related to the westward shift of the SH and western pathway EAWM, which are attributed to two dipole modes in the North Pacific and South Pacific, Atlantic Multidecadal Oscillation and Indian Ocean Basin Mode. Therefore a physically-based statistical model is established based on autumn SSTA indices. Cross-validation suggests that this statistical downscaling forecast model shows a good performance in predicting the DJF TSA.

Copper-64-labeled anti-bcl-2 PNA-peptide conjugates selectively localize to bcl-2-positive tumors in mouse models of B-cell lymphoma.

PubMed

Jia, Fang; Balaji, Baghavathy S; Gallazzi, Fabio; Lewis, Michael R

2015-11-01

The bcl-2 gene is overexpressed in non-Hodgkin's lymphoma (NHL). We have reported micro-SPECT/CT imaging of Mec-1 human lymphoma xenografts in SCID mice, using [(111)In]DOTA-anti-bcl-2-PNA-Tyr(3)-octreotate. In order to reduce normal organ accumulation and improve imaging contrast, modified monomers with neutral hydrophilic (serine, TS) or negatively charged (aspartic acid, TD) residues were synthesized as substitutes for glycine at T(14) in the PNA sequence. The parent and modified PNA-peptide conjugates were labeled with (64)Cu and evaluated in biodistribution studies and high resolution PET/CT imaging of SCID mice bearing bcl-2-positive Mec-1 xenografts as well as bcl-2-negative Ramos xenografts. Mice were administered the (64)Cu-labeled conjugates for biodistribution and imaging studies. Biodistributions were obtained from 1 to 48 h post-injection. Mice were imaged from 1 to 48 h post-injection. The parent glycine conjugate and two modified conjugates all showed selective tumor uptake in Mec-1 xenografts. The liver uptake of the serine conjugate was significantly reduced compared to the two other PNA conjugates. Its kidney uptake was highest of the three at 47.1% ID/g at 1h and dropped to 20.6% ID/g at 24h. [Copper-64]DOTA-anti-bcl-2-TS-PNA-Tyr(3)-octreotate showed tumor uptake of 1.38% ID/g at 1h and 1.06% ID/g at 24h. The tumor-to-blood ratio was increased by factor of 2 from 1h to 24h. This compound detected Mec-1 tumors by micro-PET/CT as early as 1h post-injection and at time points out to 48 h. However, the negative control Ramos tumor could not be detected. These (64)Cu-labeled, amino acid-modified PNA conjugates showed selective tumor targeting in vivo, and tumor xenografts were detected by micro-PET/CT as early as 1h post-injection, suggesting that bcl-2 expression at the mRNA level can detected by PET in mouse models of NHL. Advances in knowledge and implications for patient care Down-regulating bcl-2, an anti-apoptotic proto-oncogene, is a mechanism to reverse chemotherapy resistance in humans with NHL. Thus, bcl-2 overexpression might be considered a new independent prognostic parameter in NHL, aiding in the identification of patients at risk for treatment failure. We have developed [(64)Cu]DOTA-anti-bcl-2-PNA-Tyr(3)-octreotate conjugates for targeted antisense PET imaging. Our preclinical studies identified an effective combination of antisense and radionuclide imaging, with the goal of future clinical trials in patients. This imaging modality may improve clinical care by identifying patients who might respond better to conventional chemotherapy. Copyright © 2015. Published by Elsevier Inc.

The near-term prediction of drought and flooding conditions in the northeastern United States based on extreme phases of AMO and NAO

NASA Astrophysics Data System (ADS)

Berton, Rouzbeh; Driscoll, Charles T.; Adamowski, Jan F.

2017-10-01

A series of hydroclimatic teleconnection patterns were identified between variations in either Atlantic or Pacific oceanic indices with precipitation and discharge anomalies in the northeastern United States. We hypothesized that temporal annual or seasonal changes in discharge could be explained by variations in extreme phases of the Atlantic Multi-decadal Oscillation (AMO index, SST: Sea Surface Temperature anomalies) and the North Atlantic Oscillation (NAO index, SLP: Sea-Level Pressure anomalies) up to three seasons in advance. The Merrimack River watershed, the fourth largest basin in New England, with a drainage area of 13,000 km2, is a compelling study site because it not only provides an opportunity to investigate the teleconnection between hydrologic variables and large-scale climate circulation patterns, but also how those patterns may become obscured by anthropogenic disturbances such as river regulation or urban development. We considered precipitation and discharge data of 21 gauging stations within the Merrimack River watershed, including the Hubbard Brook Experimental Forest (HBEF), NH, with a median record length of 55 years beginning as early as 1904. The discharge anomalies were statistically significant (p-value ≤ 0.2) between extreme positive and negative phases of AMO (1857-2011) and NAO (1900-2011) and revealed the potential teleconnectivity of climate circulation patterns with discharge. Annual and seasonal correlations of discharge were examined with the extreme phases of AMO and NAO at zero-, one-, or two- year/season lags (total of 30 scenarios). When AMO was greater than 0.2, the strongest correlations of AMO and NAO with discharge were observed at headwater catchments. This correlation weakened downstream towards larger regulated and/or developed sub-basins. We introduced a simple approach for near-term prediction of drought and flooding events. An exponential decay function was regressed through the historic occurrence of the relative frequency of wet, average, and dry discharge conditions with regards to the extreme phases of AMO and NAO. While the function was decaying, the tail asymptotically merged into and stabilized at the theoretical probability of the event. As the basin scale increased, the probability of wet, average, and dry discharge conditions decreased. The Merrimack River watershed will most likely experience greater than average discharge as its extreme condition, therefore development should be avoided on flood plains. Furthermore, the current reservoir storage capacity in the Merrimack should be improved in order to accommodate excess water input and minimize flood damage. Future research should target changes in the magnitude and timing of high discharge events in order to develop adaptation strategies for aging hydraulic infrastructure in the region.

Linking North Atlantic Teleconnections to Latitudinal Variability of Wave Climate Along the North American Atlantic Coast

NASA Astrophysics Data System (ADS)

Provancha, C.; Adams, P. N.; Hegermiller, C.; Storlazzi, C. D.

2015-12-01

Shoreline change via coastal erosion and accretion is largely influenced by variations in ocean wave climate. Identifying the sources of these variations is challenging because the timing of wave energy delivery varies over multiple timescales within ocean basins. We present the results of an investigation of USACE Wave Information Studies hindcast hourly wave heights, periods, and directions along the North American Atlantic coast from 1980-2012, designed to explore links between wave climate and teleconnection patterns. Trends in median and extreme significant wave heights (SWHs) demonstrate that mean monthly SWHs increased from 1 to 5 cm/yr along the roughly 3000 km reach of study area, with changes in hurricane season waves appearing to be most influential in producing the overall trends. Distributions of SWHs categorized by North Atlantic Oscillation (NAO) phase, show that positive-period NAO SWHs are greater than negative-period NAO SWHs along the entire eastern seaboard (25°N to 45°N). The most prominent wave direction off Cape Cod, MA during positive-period NAO is approximately 105°, as compared to approximately 75° during negative-period NAO. Prominent wave directions between Cape Canaveral, FL, and Savannah, GA exhibit a similar shift but during opposite phases of the NAO. The results of this analysis suggest that the atmosphere-ocean interactions associated with contrasting NAO phases can significantly change the wave climate observed offshore along the North American Atlantic coast, altering alongshore wave energy fluxes and sediment transport patterns along the coast.

Condition of Si crystal formation by vaporizing Na from NaSi

NASA Astrophysics Data System (ADS)

Morito, Haruhiko; Karahashi, Taiki; Yamane, Hisanori

2012-09-01

NaSi was heated at various Na vapor pressures (pNa 0.1-1.2 atm) and temperatures (973-1173 K) to investigate the condition of Si crystal formation from NaSi by Na evaporation. Silicon single crystals 1-3 mm in diameter were grown by evaporation of Na from Na-Si melt at 1173 K and pNa=0.74 atm.

Side to Side Supercharging Allograft

DTIC Science & Technology

Side-to-side grafting between the PNA and regional in situ nerve trunks may be able to increase the effective critical length of the PNA. Nerve tissue...and provides an effective scaffolding system but depends on in situ Schwann cell migration to support axon regeneration. Though this process appears...loss and retraction can result in segmental gaps requiring some form of grafting. Autologous nerve grafting is associated with potential donor

Computer simulation of the linear and nonlinear optical susceptibilities of p-nitroaniline in cyclohexane, 1,4-dioxane, and tetrahydrofuran in quadrupolar approximation. II. Local field effects and optical susceptibilitities.

PubMed

Reis, H; Papadopoulos, M G; Grzybowski, A

2006-09-21

This is the second part of a study to elucidate the local field effects on the nonlinear optical properties of p-nitroaniline (pNA) in three solvents of different multipolar character, that is, cyclohexane (CH), 1,4-dioxane (DI), and tetrahydrofuran (THF), employing a discrete description of the solutions. By the use of liquid structure information from molecular dynamics simulations and molecular properties computed by high-level ab initio methods, the local field and local field gradients on p-nitroaniline and the solvent molecules are computed in quadrupolar approximation. To validate the simulations and the induction model, static and dynamic (non)linear properties of the pure solvents are also computed. With the exception of the static dielectric constant of pure THF, a good agreement between computed and experimental refractive indices, dielectric constants, and third harmonic generation signals is obtained for the solvents. For the solutions, it is found that multipole moments up to two orders higher than quadrupole have a negligible influence on the local fields on pNA, if a simple distribution model is employed for the electric properties of pNA. Quadrupole effects are found to be nonnegligible in all three solvents but are especially pronounced in the 1,4-dioxane solvent, in which the local fields are similar to those in THF, although the dielectric constant of DI is 2.2 and that of the simulated THF is 5.4. The electric-field-induced second harmonic generation (EFISH) signal and the hyper-Rayleigh scattering signal of pNA in the solutions computed with the local field are in good to fair agreement with available experimental results. This confirms the effect of the "dioxane anomaly" also on nonlinear optical properties. Predictions based on an ellipsoidal Onsager model as applied by experimentalists are in very good agreement with the discrete model predictions. This is in contrast to a recent discrete reaction field calculation of pNA in 1,4-dioxane, which found that the predicted first hyperpolarizability of pNA deviated strongly from the predictions obtained using Onsager-Lorentz local field factors.

Influence of PNA containing 8-aza-7-deazaadenine on structure stability and binding affinity of PNA·DNA duplex: insights from thermodynamics, counter ion, hydration and molecular dynamics analysis.

PubMed

Gupta, Sharad K; Sur, Souvik; Prasad Ojha, Rajendra; Tandon, Vibha

2013-07-01

This paper describes the synthesis of a novel 8-aza-7-deazapurin-2,6-diamine (DPP)-containing peptide nucleic acid (PNA) monomer and Boc protecting group-based oligomerization of PNA, replacing adenine (A) with DPP monomers in the PNA strand. The PNA oligomers were synthesized against the biologically relevant SV40 promoter region (2494-AATTTTTTTTATTTA-2508) of pEGFP-N3 plasmid. The DPP-PNA·DNA duplex showed enhanced stability as compared to normal duplex (A-PNA·DNA). The electronic distribution of DPP monomer suggested that DPP had better electron donor properties over 2,6-diamino purine. UV melting and thermodynamic analysis revealed that the PNA oligomer containing a diaminopyrazolo(3,4-d)pyrimidine moiety (DPP) stabilized the PNA·DNA hybrids compared to A-PNA·DNA. DPP-PNA·DNA duplex showed higher water activity (Δnw = 38.5) in comparison to A-PNA·DNA duplex (Δnw = 14.5). The 50 ns molecular dynamics simulations of PNA·DNA duplex containing DPP or unmodified nucleobase-A showed average H-bond distances in the DPP-dT base pair of 2.90 Å (OH-N bond) and 2.91 Å (NH-N bond), which were comparably shorter than in the A-dT base pair, in which the average distances were 3.18 Å (OH-N bond) and 2.97 Å (NH-N bond), and there was one additional H-bond in the DPP-dT base pair of around 2.98 Å (O2H-N2 bond), supporting the higher stability of DPP-PNA·DNA. The analysis of molecular dynamics simulation data showed that the system binding free energy increased at a rate of approximately -4.5 kcal mol(-1) per DPP base of the PNA·DNA duplex. In summary, increased thermal stability, stronger hydrogen bonding and more stable conformation in the DPP-PNA·DNA duplex make it a better candidate as antisense/antigene therapeutic agents.

Amplified summer warming in Europe-West Asia and Northeast Asia after the mid-1990s

NASA Astrophysics Data System (ADS)

Hong, Xiaowei; Lu, Riyu; Li, Shuanglin

2017-09-01

Regional temperature changes are a crucial factor in affecting agriculture, ecosystems and societies, which depend greatly on local temperatures. We identify a nonuniform warming pattern in summer around the mid-1990s over the Eurasian continent, with a predominant amplified warming over Europe-West Asia and Northeast Asia but much weaker warming over Central Asia. It is found that the nonuniform warming concurs with both the phase shift of the Atlantic Multi-decadal Oscillation (AMO) and the decadal change in the Silk Road Pattern (SRP), which is an upper-tropospheric teleconnection pattern over the Eurasian continent during summer. We suggest that the AMO may modulate the decadal change in SRP and then induce the zonal asymmetry in temperature changes. Our results have important implications for decadal prediction of regional warming pattern in Eurasia based on the predictable AMO.

Summer monsoon circulation and precipitation over the tropical Indian Ocean during ENSO in the NCEP climate forecast system

NASA Astrophysics Data System (ADS)

Chowdary, J. S.; Chaudhari, H. S.; Gnanaseelan, C.; Parekh, Anant; Suryachandra Rao, A.; Sreenivas, P.; Pokhrel, S.; Singh, P.

2014-04-01

This study investigates the El Niño Southern Oscillation (ENSO) teleconnections to tropical Indian Ocean (TIO) and their relationship with the Indian summer monsoon in the coupled general circulation model climate forecast system (CFS). The model shows good skill in simulating the impact of El Niño over the Indian Oceanic rim during its decay phase (the summer following peak phase of El Niño). Summer surface circulation patterns during the developing phase of El Niño are more influenced by local Sea Surface Temperature (SST) anomalies in the model unlike in observations. Eastern TIO cooling similar to that of Indian Ocean Dipole (IOD) is a dominant model feature in summer. This anomalous SST pattern therefore is attributed to the tendency of the model to simulate more frequent IOD events. On the other hand, in the model baroclinic response to the diabatic heating anomalies induced by the El Niño related warm SSTs is weak, resulting in reduced zonal extension of the Rossby wave response. This is mostly due to weak eastern Pacific summer time SST anomalies in the model during the developing phase of El Niño as compared to observations. Both eastern TIO cooling and weak SST warming in El Niño region combined together undermine the ENSO teleconnections to the TIO and south Asia regions. The model is able to capture the spatial patterns of SST, circulation and precipitation well during the decay phase of El Niño over the Indo-western Pacific including the typical spring asymmetric mode and summer basin-wide warming in TIO. The model simulated El Niño decay one or two seasons later, resulting long persistent warm SST and circulation anomalies mainly over the southwest TIO. In response to the late decay of El Niño, Ekman pumping shows two maxima over the southern TIO. In conjunction with this unrealistic Ekman pumping, westward propagating Rossby waves display two peaks, which play key role in the long-persistence of the TIO warming in the model (for more than a season after summer). This study strongly supports the need of simulating the correct onset and decay phases of El Niño/La Niña for capturing the realistic ENSO teleconnections. These results have strong implications for the forecasting of Indian summer monsoon as this model is currently being adopted as an operational model in India.

Global Climate Teleconnections to Forecast Increased Risk of Vector-Borne Animal and Human Disease Transmission

USDA-ARS?s Scientific Manuscript database

We willexamine how climate teleconnect ions and variability impact vector biology and vector borne disease ecology, and demonstrate that global climate monitoring can be used to anticipate and forecast epidemics and epizootics. In this context we willexamine significant worldwide weather anomalies t...

Steroid injection and needle aponeurotomy for Dupuytren contracture: a randomized, controlled study.

PubMed

McMillan, Catherine; Binhammer, Paul

2012-07-01

To compare flexion deformity at 6 months in patients with Dupuytren contracture who had percutaneous needle aponeurotomy (PNA) combined with a series of triamcinolone acetonide (TA) injections to that of patients who had PNA alone. Forty-seven patients with Dupuytren disease who were candidates for PNA (at least 1 contracture of at least 20°) participated in the study. Patients were randomized either to receive TA injections immediately following and 6 weeks and 3 months after the procedure or to receive no injections. Injections were administered into cords. The number of injections and the amount of TA per injection was determined based on the number of digits involved and the cord size. All subjects returned for 3 follow-up visits after the procedure, and contractures were measured using a goniometer. Change in total active extension deficit (TAED) was analyzed using a repeated measures analysis of variance to assess for differences between groups, time points, and interaction between group and time point. Descriptive statistics were calculated for all variables of interest. Continuous measures were summarized using means and standard deviations. There was no significant difference in TAED between groups before cord aponeurotomy. Correction at 6 months was 87% of preoperative TAED for the TA group versus 64% for the control group. This difference was statistically significant. The amount of TA administered did not correlate with TAED improvement. The study group who received TA in combination with PNA experienced a significantly greater degree of correction of flexion deformity at 6 months than those who had PNA alone. Copyright © 2012 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Prenatal androgen excess enhances stimulation of the GNRH pulse in pubertal female rats.

PubMed

Yan, Xiaonan; Yuan, Chun; Zhao, Nannan; Cui, Yugui; Liu, Jiayin

2014-07-01

In adolescent girls with polycystic ovary syndrome (PCOS), neuroendocrine derangements manifest after the onset of puberty, characterized by rapid LH pulse frequency. The early mechanism underlying the pubertal regulation of the GNRH/LH pulsatile release in adolescents with PCOS remains uncertain. To determine the effects of prenatal androgen exposure on the activation of GNRH neurons and generation of LH pulse at puberty, we administrated 5α-dihydrotestosterone to pregnant rats and observed serum LH levels and expression of hypothalamic genes in female offspring from postnatal 4 to 8 weeks. The 6-week-old prenatally androgenized (PNA) female rats exhibited an increase in LH pulse frequency. The hypothalamic expression of neurokinin B (Nkb (Tac2)) and Lepr mRNA levels in PNA rats increased remarkably before puberty and remained high during puberty, whereas elevated Kiss1 mRNA levels were detected only after the onset of puberty. Exogenous kisspeptin, NK3R agonist, and leptin triggered tonic stimulation of GNRH neurons and increased LH secretion in 6-week-old PNA rats. Leptin upregulated Kiss1 mRNA levels in the hypothalamus of pubertal PNA rats; however, pretreatment with a kisspeptin antagonist failed to suppress the elevated serum LH stimulated by leptin, indicating that the stimulatory effects of leptin may be conveyed indirectly to GNRH neurons via other neural components within the GNRH neuronal network, rather than through the kisspeptin-GPR54 pathway. These findings validate the hypotheses that NKB and leptin play an essential role in the activation of GNRH neurons and initiation of increased LH pulse frequency in PNA female rats at puberty and that kisspeptin may coordinate their stimulatory effects on LH release. © 2014 Society for Endocrinology.

Oxacillin sensitization of methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus pseudintermedius by antisense peptide nucleic acids in vitro.

PubMed

Goh, Shan; Loeffler, Anette; Lloyd, David H; Nair, Sean P; Good, Liam

2015-11-11

Antibiotic resistance genes can be targeted by antisense agents, which can reduce their expression and thus restore cellular susceptibility to existing antibiotics. Antisense inhibitors can be gene and pathogen specific, or designed to inhibit a group of bacteria having conserved sequences within resistance genes. Here, we aimed to develop antisense peptide nucleic acids (PNAs) that could be used to effectively restore susceptibility to β-lactams in methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP). Antisense PNAs specific for conserved regions of the mobilisable gene mecA, and the growth essential gene, ftsZ, were designed. Clinical MRSA and MRSP strains of high oxacillin resistance were treated with PNAs and assayed for reduction in colony forming units on oxacillin plates, reduction in target gene mRNA levels, and cell size. Anti-mecA PNA at 7.5 and 2.5 μM reduced mecA mRNA in MRSA and MRSP (p < 0.05). At these PNA concentrations, 66 % of MRSA and 92 % of MRSP cells were killed by oxacillin (p < 0.01). Anti-ftsZ PNA at 7.5 and 2.5 μM reduced ftsZ mRNA in MRSA and MRSP, respectively (p ≤ 0.05). At these PNA concentrations, 86 % of MRSA cells and 95 % of MRSP cells were killed by oxacillin (p < 0.05). Anti-ftsZ PNAs resulted in swelling of bacterial cells. Scrambled PNA controls did not affect MRSA but sensitized MRSP moderately to oxacillin without affecting mRNA levels. The antisense PNAs effects observed provide in vitro proof of concept that this approach can be used to reverse β-lactam resistance in staphylococci. Further studies are warranted as clinical treatment alternatives are needed.

A novel mode for transcription inhibition mediated by PNA-induced R-loops with a model in vitro system.

PubMed

D'Souza, Alicia D; Belotserkovskii, Boris P; Hanawalt, Philip C

2018-02-01

The selective inhibition of transcription of a chosen gene by an artificial agent has numerous applications. Usually, these agents are designed to bind a specific nucleotide sequence in the promoter or within the transcribed region of the chosen gene. However, since optimal binding sites might not exist within the gene, it is of interest to explore the possibility of transcription inhibition when the agent is designed to bind at other locations. One of these possibilities arises when an additional transcription initiation site (e.g. secondary promoter) is present upstream from the primary promoter of the target gene. In this case, transcription inhibition might be achieved by inducing the formation of an RNA-DNA hybrid (R-loop) upon transcription from the secondary promoter. The R-loop could extend into the region of the primary promoter, to interfere with promoter recognition by RNA polymerase and thereby inhibit transcription. As a sequence-specific R-loop-inducing agent, a peptide nucleic acid (PNA) could be designed to facilitate R-loop formation by sequestering the non-template DNA strand. To investigate this mode for transcription inhibition, we have employed a model system in which a PNA binding site is localized between the T3 and T7 phage RNA polymerase promoters, which respectively assume the roles of primary and secondary promoters. In accord with our model, we have demonstrated that with PNA-bound DNA substrates, transcription from the T7 promoter reduces transcription from the T3 promoter by 30-fold, while in the absence of PNA binding there is no significant effect of T7 transcription upon T3 transcription. Copyright © 2018 Elsevier B.V. All rights reserved.

Pain Adaptability in Individuals With Chronic Musculoskeletal Pain Is Not Associated With Conditioned Pain Modulation.

PubMed

Wan, Dawn Wong Lit; Arendt-Nielsen, Lars; Wang, Kelun; Xue, Charlie Changli; Wang, Yanyi; Zheng, Zhen

2018-03-27

Healthy humans can be divided into the pain adaptive (PA) and the pain nonadaptive (PNA) groups; PA showed a greater decrease in pain rating to a cold pressor test (CPT) than PNA. This study examined if the dichotomy of pain adaptability existed in individuals with chronic musculoskeletal pain. CPTs at 2°C and 7°C were used to assess the status of pain adaptability in participants with either chronic nonspecific low back pain or knee osteoarthritis. The participants' potency of conditioned pain modulation (CPM) and local inhibition were measured. The strengths of pain adaptability at both CPTs were highly correlated. PA and PNA did not differ in their demographic characteristics, pain thresholds from thermal and pressure stimuli, or potency of local inhibition or CPM. PA reached their maximum pain faster than PNA (t 41 = -2.76, P < .01), and had a gradual reduction of pain unpleasantness over 7 days whereas PNA did not (F 6,246  = 3.01, P = .01). The dichotomy of pain adaptability exists in musculoskeletal pain patients. Consistent with the healthy human study, the strength of pain adaptability and potency of CPM are not related. Pain adaptability could be another form of endogenous pain inhibition of which clinical implication is yet to be understood. The dichotomy of pain adaptability was identified in healthy humans. The current study confirms that this dichotomy also exists in individuals with chronic musculoskeletal pain, and could be reliably assessed with CPTs at 2°C and 7°C. Similar to the healthy human study, pain adaptability is not associated with CPM, and may reflect the temporal aspect of pain inhibition. Copyright © 2018 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Stable Isotopic Variations in Columnar Cacti: are Responses to Climate Recorded in Spines?

NASA Astrophysics Data System (ADS)

English, N. B.; Dettman, D. L.; Williams, D. G.

2004-12-01

The behavior of the North American monsoon (NAM), particularly with respect to times of continental drought and its relationship to the Pacific-North American (PNA) teleconnection pattern and the El Nino/Southern Oscillation (ENSO) is of great interest to paleoclimatologists and water managers. Long-term instrumental precipitation and tree ring records in the southwestern United States and northwestern Mexico at low elevations are sparse and this has hindered research on NAM variability at interannual timescales. Saguaro cacti (Carnegiea gigantea) and other columnar cacti in North and South America are long-lived and have the potential to record climate variability on land with high temporal and spatial resolution. The vertical sequence of spines on the saguaro's exterior represents a high resolution (4 to 6 per year), and long (over 150 years) record of environmental change. We present results from an experiment where we tracked the oxygen isotopic values in the source waters, stem tissue waters and spine tissue for three treatments over the course of three months. These data are then compared to a previously developed mechanistic model of isotopic variation that reflects the physiological responses of Saguaro to climate variation over seasonal to century long time-scales. We also present the rationale for a new method to determine the growth rate of columnar cacti using the radiocarbon bomb spike. Our measurements reveal that oxygen and hydrogen isotopic variation among the sequentially produced and persistent spines covering the saguaro body record fluctuations in saguaro water balance. The model successfully predicts isotopic variation in spines and constrains controlling variables, yielding a powerful and high-resolution stable isotope index of water stress in the low desert. The development and refinement of an isotopic model for saguaro will serve as the basis for models applied to other species of columnar cacti in North and South America. The role of the tropics in global climate change is poorly understood and precise chronologies of tropical climate change are needed to place empirical constraints on competing theories and models. In particular, the use of continental records from columnar cacti in South America could identify ENSO periods in the last century and provide empirical constraints on the inputs of Atlantic (monsoonal) versus Pacific (winter) moisture to the Altiplano during ENSO and other important climatological phenomena.

Characterisation of glycoconjugate sugar residues in the vomeronasal organ of the armadillo Chaetophractus villosus (Mammalia, xenarthra)

PubMed Central

CARMANCHAHI, P. D.; FERRARI, C. C.; ALDANA MARCOS, H. J.; AFFANNI, J. M.; SONEZ, C. A.; PAZ, D. A.

2000-01-01

Conventional carbohydrate histochemistry and the binding patterns of 21 lectins were analysed to characterise the glycoconjugate content in the components of the vomeronasal organ of the armadillo Chaetophractus villosus. The mucomicrovillous complex of the sensory epithelium bound most of the lectins studied. No reaction was observed with Con A, PSA, S-Con A and SBA, and the sustentacular cells were stained with UEA-I, DSL, LEL, STL and Con A. The vomeronasal receptor neurons were labelled with S-WGA, WGA, PNA, UEA-I, STL, Con A, S-Con A, ECL and RCA120. The basal cell layer reacted with S-WGA, WGA, LCA, UEA-I, DSL, LEL, STL, Con A, JAC and VVA. The nonsensory epithelium exhibited a differential staining in relation to the different components. The mucociliary complex stained with ECL, DBA, JAC, RCA120, STL, LCA, PHA-E, PHA-L, LEL, BSL-I and VVA. However, SJA and UEA-I stained the mucus complex lining a subpopulation of columnar cells. The cytoplasm and cell membranes of columnar cells was labelled with DBA, DSL and LCA. The apical region of these cells exhibited moderate reactivity with LEL and SJA. None of the lectins bound specifically to secretory granules of the nonsecretory cells. Basal cells of the nonsensory epithelium were labelled with DSL, LEL, LCA, BSL-I and STL. The vomeronasal glands showed a positive reaction with WGA, DSL, LEL, LCA, DBA, PNA, RCA120 and SBA. Subpopulations of acinar cells were observed with ECL, S-WGA, Con A, S-Con A and DBA. PNA and RCA120 stained the cells lining the glandular ducts. In comparison with previous results obtained in the olfactory mucosa of the same group of armadillos, the carbohydrate composition of the vomeronasal organ sensory epithelium differed from the olfactory sensory epithelium. This is probably related to the different nature of molecules involved in the perireceptor processes. PMID:10853958

Time-resolved energy transfer in DNA sequence detection using water-soluble conjugated polymers: the role of electrostatic and hydrophobic interactions.

PubMed

Xu, Qing-Hua; Gaylord, Brent S; Wang, Shu; Bazan, Guillermo C; Moses, Daniel; Heeger, Alan J

2004-08-10

We have investigated the energy transfer processes in DNA sequence detection by using cationic conjugated polymers and peptide nucleic acid (PNA) probes with ultrafast pump-dump-emission spectroscopy. Pump-dump-emission spectroscopy provides femtosecond temporal resolution and high sensitivity and avoids interference from the solvent response. The energy transfer from donor (the conjugated polymer) to acceptor (a fluorescent molecule attached to a PNA terminus) has been time resolved. The results indicate that both electrostatic and hydrophobic interactions contribute to the formation of cationic conjugated polymers/PNA-C/DNA complexes. The two interactions result in two different binding conformations. This picture is supported by the average donor-acceptor separations as estimated from time-resolved and steady-state measurements. Electrostatic interactions dominate at low concentrations and in mixed solvents.

Time-resolved energy transfer in DNA sequence detection using water-soluble conjugated polymers: The role of electrostatic and hydrophobic interactions

PubMed Central

Xu, Qing-Hua; Gaylord, Brent S.; Wang, Shu; Bazan, Guillermo C.; Moses, Daniel; Heeger, Alan J.

2004-01-01

We have investigated the energy transfer processes in DNA sequence detection by using cationic conjugated polymers and peptide nucleic acid (PNA) probes with ultrafast pump-dump-emission spectroscopy. Pump-dump-emission spectroscopy provides femtosecond temporal resolution and high sensitivity and avoids interference from the solvent response. The energy transfer from donor (the conjugated polymer) to acceptor (a fluorescent molecule attached to a PNA terminus) has been time resolved. The results indicate that both electrostatic and hydrophobic interactions contribute to the formation of cationic conjugated polymers/PNA-C/DNA complexes. The two interactions result in two different binding conformations. This picture is supported by the average donor–acceptor separations as estimated from time-resolved and steady-state measurements. Electrostatic interactions dominate at low concentrations and in mixed solvents. PMID:15282375

Connections between the tropical Pacific Ocean, Arctic sea ice, and anomalous northeastern Pacific ridging

NASA Astrophysics Data System (ADS)

Swain, D. L.; Singh, D.; Horton, D. E.; Mankin, J. S.; Ballard, T.; Thomas, L. N.; Diffenbaugh, N. S.

2016-12-01

The ongoing and severe drought in California is linked to the multi-year persistence of anomalously strong ridging along the west coast of North America, which has deflected the Pacific storm track north of its climatological mean position. Recent work has shown that that highly amplified and strongly meridional atmospheric flow patterns in this region similar to the "Ridiculously Resilient Ridge" have become more common in recent decades. Previous investigations have suggested multiple possible contributors to this conspicuous atmospheric anomaly—including remote teleconnections to unusual tropical Pacific Ocean warmth and/or reduced Arctic sea ice, internal (natural) atmospheric variability, and anthropogenic forcing due to greenhouse gas emissions. Here, we explore observed relationships between mid-tropospheric atmospheric structure in this region and five hypothesized surface forcings: sea ice extent in the (1) Barents/Kara and (2) Beaufort/Chukchi regions, and sea surface temperatures in the (3) extratropical northeastern Pacific Ocean, (4) western tropical Pacific Ocean, and (5) eastern tropical Pacific Ocean. Using a predictive model based upon these observed relationships, we also investigate whether the failure of the powerful 2015-2016 El Niño event to bring above-average precipitation to California could have been predicted based upon these teleconnections.

Triple Helical Recognition of Pyrimidine Inversions in Polypurine Tracts of RNA by Nucleobase-modified PNA

PubMed Central

Gupta, Pankaj; Zengeya, Thomas; Rozners, Eriks

2013-01-01

Peptide nucleic acids containing 2-pyrimidinone (P) and 3-oxo-2,3-dihydropyridazine (E) heterocycles recognized C-G and U-A inversions in a polypurine tract of double helical RNA with high affinity and sequence selectivity at pH 6.25. E-modified PNA bound strongly to bacterial A-site RNA, while no binding was observed to the human A-site RNA. PMID:21909545

Ontogeny and reversal of brain circuit abnormalities in a preclinical model of PCOS.

PubMed

Silva, Mauro Sb; Prescott, Melanie; Campbell, Rebecca E

2018-04-05

Androgen excess is a hallmark of polycystic ovary syndrome (PCOS), a prevalent yet poorly understood endocrine disorder. Evidence from women and preclinical animal models suggests that elevated perinatal androgens can elicit PCOS onset in adulthood, implying androgen actions in both PCOS ontogeny and adult pathophysiology. Prenatally androgenized (PNA) mice exhibit a robust increase of progesterone-sensitive GABAergic inputs to gonadotropin-releasing hormone (GnRH) neurons implicated in the pathogenesis of PCOS. It is unclear when altered GABAergic wiring develops in the brain, and whether these central abnormalities are dependent upon adult androgen excess. Using GnRH-GFP-transgenic mice, we determined that increased GABA input to GnRH neurons occurs prior to androgen excess and the manifestation of reproductive impairments in PNA mice. These data suggest that brain circuit abnormalities precede the postpubertal development of PCOS traits. Despite the apparent developmental programming of circuit abnormalities, long-term blockade of androgen receptor signaling from early adulthood rescued normal GABAergic wiring onto GnRH neurons, improved ovarian morphology, and restored reproductive cycles in PNA mice. Therefore, androgen excess maintains changes in female brain wiring linked to PCOS features and the blockade of androgen receptor signaling reverses both the central and peripheral PNA-induced PCOS phenotype.

Point-of-care detection and real-time monitoring of intravenously delivered drugs via tubing with an integrated SERS sensor.

PubMed

Wu, Hsin-Yu; Cunningham, Brian T

2014-05-21

We demonstrate an approach for detection, identification, and kinetic monitoring of drugs flowing within tubing, through the use of a plasmonic nanodome array (PNA) surface. The PNA structures are fabricated using a low-cost nanoreplica molding process upon a flexible plastic substrate that is subsequently integrated with a flow cell that connects in series with ordinary intravenous (IV) drug delivery tubing. To investigate the potential clinical applications for point-of-care detection and real-time monitoring, we perform SERS detection of ten pharmaceutical compounds (hydrocodone, levorphanol, morphine, oxycodone, methadone, phenobarbital, dopamine, diltiazem, promethazine, and mitoxantrone). We demonstrate dose-dependent SERS signal magnitude, resulting in detection limits (ng ml(-1)) well below typical administered dosages (mg ml(-1)). Further, we show that the detected drugs are not permanently attached to the PNA surface, and thus our approach is capable of performing continuous monitoring of drug delivery as materials flow through IV tubing that is connected in series with the sensor. Finally, we demonstrate the potential co-detection of multiple drugs when they are mixed together, and show excellent reproducibility and stability of SERS measurements for periods extending at least five days. The capabilities reported here demonstrate the potential to use PNA SERS surfaces for enhancing the safety of IV drug delivery.

Intracellular delivery of peptide nucleic acid and organic molecules using zeolite-L nanocrystals.

PubMed

Bertucci, Alessandro; Lülf, Henning; Septiadi, Dedy; Manicardi, Alex; Corradini, Roberto; De Cola, Luisa

2014-11-01

The design and synthesis of smart nanomaterials can provide interesting potential applications for biomedical purposes from bioimaging to drug delivery. Manufacturing multifunctional systems in a way to carry bioactive molecules, like peptide nucleic acids able to recognize specific targets in living cells, represents an achievement towards the development of highly selective tools for both diagnosis and therapeutics. This work describes a very first example of the use of zeolite nanocrystals as multifunctional nanocarriers to deliver simultaneously PNA and organic molecules into living cells. Zeolite-L nanocrystals are functionalized by covalently attaching the PNA probes onto the surface, while the channel system is filled with fluorescent guest molecules. The cellular uptake of the PNA/Zeolite-L hybrid material is then significantly increased by coating the whole system with a thin layer of biodegradable poly-L-lysine. The delivery of DAPI as a model drug molecule, inserted into the zeolite pores, is also demonstrated to occur in the cells, proving the multifunctional ability of the system. Using this zeolite nanosystem carrying PNA probes designed to target specific RNA sequences of interest in living cells could open new possibilities for theranostic and gene therapy applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ontogeny and reversal of brain circuit abnormalities in a preclinical model of PCOS

PubMed Central

Silva, Mauro S.B.; Prescott, Melanie; Campbell, Rebecca E.

2018-01-01

Androgen excess is a hallmark of polycystic ovary syndrome (PCOS), a prevalent yet poorly understood endocrine disorder. Evidence from women and preclinical animal models suggests that elevated perinatal androgens can elicit PCOS onset in adulthood, implying androgen actions in both PCOS ontogeny and adult pathophysiology. Prenatally androgenized (PNA) mice exhibit a robust increase of progesterone-sensitive GABAergic inputs to gonadotropin-releasing hormone (GnRH) neurons implicated in the pathogenesis of PCOS. It is unclear when altered GABAergic wiring develops in the brain, and whether these central abnormalities are dependent upon adult androgen excess. Using GnRH-GFP–transgenic mice, we determined that increased GABA input to GnRH neurons occurs prior to androgen excess and the manifestation of reproductive impairments in PNA mice. These data suggest that brain circuit abnormalities precede the postpubertal development of PCOS traits. Despite the apparent developmental programming of circuit abnormalities, long-term blockade of androgen receptor signaling from early adulthood rescued normal GABAergic wiring onto GnRH neurons, improved ovarian morphology, and restored reproductive cycles in PNA mice. Therefore, androgen excess maintains changes in female brain wiring linked to PCOS features and the blockade of androgen receptor signaling reverses both the central and peripheral PNA-induced PCOS phenotype. PMID:29618656

[Identification of hepatitis B virus YMDD point mutation using peptide nucleic acid clamping PCR].

PubMed

Zhang, Yingying; He, Haitang; Yang, Jie; Hou, Jinlin

2013-06-01

To establish a peptide nucleic acid clamping PCR assay for detecting hepatitis B virus (HBV) drug resistance mutation. RtM204I (ATT) mutant, rtM204V (GTG) mutant and rtM204 (ATG) wild-type plasmids mixed at different ratios were detected for mutations by PNA clamping PCR assay and direct sequencing, and the sensitivity and specificity of the two methods were compared. Serum samples from 85 patients with chronic HBV infection were detected for drug resistance using the two methods. The sensitivity of PNA-PCR assay was 0.001% in a 10(5)-fold excess of wild-type HBV DNA with a detection limit of 10(1) copies. The sensitivity of direct sequencing was 10% with a detection limit of 10(4) copies. Mutants were detected in 73 of the 85 serum samples (85.9%), including YIDD in 40 samples, YVDD in 23 samples, and YIDD+YVDD in 10 samples. The agreement of PNA-PCR assay with direct sequencing was only 40% (34/85, YIDD in 21 samples, YVDD in 11 samples, and YIDD+YVDD in 2 samples). Neither of the two methods yielded positive results for the negative control samples, suggesting their good specificity. PNA-PCR assay appears to be a more sensitive and rapid assay for detection of HBV genotypic resistance.

Fluorogenic PNA probes

PubMed Central

2018-01-01

Fluorogenic oligonucleotide probes that can produce a change in fluorescence signal upon binding to specific biomolecular targets, including nucleic acids as well as non-nucleic acid targets, such as proteins and small molecules, have applications in various important areas. These include diagnostics, drug development and as tools for studying biomolecular interactions in situ and in real time. The probes usually consist of a labeled oligonucleotide strand as a recognition element together with a mechanism for signal transduction that can translate the binding event into a measurable signal. While a number of strategies have been developed for the signal transduction, relatively little attention has been paid to the recognition element. Peptide nucleic acids (PNA) are DNA mimics with several favorable properties making them a potential alternative to natural nucleic acids for the development of fluorogenic probes, including their very strong and specific recognition and excellent chemical and biological stabilities in addition to their ability to bind to structured nucleic acid targets. In addition, the uncharged backbone of PNA allows for other unique designs that cannot be performed with oligonucleotides or analogues with negatively-charged backbones. This review aims to introduce the principle, showcase state-of-the-art technologies and update recent developments in the areas of fluorogenic PNA probes during the past 20 years. PMID:29507634

Synthesis and characterisation of hetero-bimetallic organometallic phenylalanine and PNA monomer derivatives.

PubMed

Gasser, Gilles; Brosch, Oliver; Ewers, Alexandra; Weyhermüller, Thomas; Metzler-Nolte, Nils

2009-06-14

The rational, sequential synthesis of two hetero-bimetallic derivatives of the amino acid phenylalanine and one thymine (T) peptide nucleic acid (PNA) monomer is reported. Ferrocene carboxylic acid and (eta-ethene)bis(triphenylphosphine)platinum(0) were successfully reacted with propargylamide amino acid (1a and 1b) or a T PNA monomer derivative (6) to give the expected three bimetallic compounds 4a, 4b and 9 in good yield. An enzymatic route using cross-linked enzyme crystals (CLEC) of subtilopeptidase A in organic solvents gave the ferrocene carboxylate phenylalanine propargylamide precursor (Fc-CO-Phe-NH-CH(2)-CCH, 3a) in comparable yield and purity to the traditional deprotection-peptide coupling sequence. (31)P NMR spectra of these bioorganometallics showed two doublets with (195)Pt satellites corresponding to two chemically different (31)P atoms. Interestingly, in the case of the T PNA monomer derivative 9, these signals were also doubled in a 60 : 40 ratio as a consequence of the existence of two slowly interconverting isomers in solution. Furthermore, the single-crystal X-ray structures of 3a and the hetero-bimetallic phenylalanine derivative 4b were determined, showing the presence of the two organometallics moieties separated by ca. 8.5 A in 4b as well as illustrating the stability of such compounds.

Impact of the global SST gradients changes on the Antarctic ice sheet surface mass balance through the Plio/Pliocene transition

NASA Astrophysics Data System (ADS)

Colleoni, Florence; Florindo, Fabio; McKay, Robert; Golledge, Nicholas; Sangiorgi, Francesca; Montoli, Enea; Masina, Simona; Cherchi, Annalisa; De Santis, Laura

2017-04-01

Sea Surface Temperatures (SST) reconstructions have shown that the Pliocene global zonal and meridional temperature gradients were different from today, implying changes of atmospheric and oceanic circulations, and thus of the main teleconnections. The impact of the main atmospheric teleconnections on the surface mass balance (SMB) of the Antarctic ice sheet (AIS) in the past has been seldom investigated. The ANDRILL marine record have shown that at the end of the Pliocene, the ice sheet expanded in the Ross Sea concomitantly with the expansion of the sea ice cover. This would have enhanced the formation of bottom waters that in turn, would have fostered upwelling along the West African coast and along the coast of Peru. The impact of Antarctica on the tropical climate dynamics has been shown by previous studies. To close the loop, this work investigates the impact of the tropical and high-latitude SST cooling on the main atmospheric teleconnections and then on the Antarctic SMB through the Plio/Pleistocene transition. Idealized Atmospheric General Circulation Model simulations are performed, in which high-latitude and tropical SST cooling are prescribed starting from the Pliocene SST. The atmospheric conditions obtained are then used to force an ice sheet model and a stand-alone energy balance model to investigate the impact on the SMB of the two main atmospheric teleconnections active in the Southern Hemisphere, namely the Southern Annular Mode (SAM) and the Pacific-South-American oscillation (PSA. In agreement with ANDRILL marine records, results show that the Easterlies strengthen along the Antarctic coasts during the Plio/Pleistocene transition. This, however, occurs only after cooling the tropical SSTs in the AGCM simulations. More importantly, the cooling of the tropical SST, through the strengthening of the PSA, has the largest influence on the spatial distribution of the climatic anomalies over Antarctica. This explains most of the SMB patterns simulated by the ice sheet model. In particular, the PSA fosters positive SMB over the Victoria Land, the Wilson Basin, the Aurora Basin and Prydz Bay that were partly deglaciated during the warm Pliocene. While the amplitude of the ice thickness changes due to the SAM and the PSA remains of the same order of today, i.e, few tens of meters, the main impact occurs in strategic areas of the AIS dynamics.

The influence of north Pacific atmospheric circulation on streamflow in the west

USGS Publications Warehouse

Cayan, Daniel R.; Peterson, David H.

1989-01-01

The annual cycle and nonseasonal variability of streamflow over western North America and Hawaii is studied in terms of atmospheric forcing elements. This study uses several decades of monthly average streamflow beginning as early as the late 1800's over a network of 38 stations. In addition to a strong annual cycle in mean streamflow and its variance at most of the stations, there is also a distinct annual cycle in the autocorrelation of anomalies that is related to the interplay between the annual cycles of temperature and precipitation. Of particular importance to these lag effects is the well-known role of water stored as snow pack, which controls the delay between peak precipitation and peak flow and also introduces persistence into the nonseasonal streamflow anomalies, with time scales from 1 month to over 1 year. The degree to which streamflow is related to winter atmospheric circulation over the North Pacific and western North America is tested using correlations with time averaged, gridded sea level pressure (SLP), which begins in 1899. Streamflow fluctuations show significant large-scale correlations for the winter (December through February) mean SLP anomaly patterns over the North Pacific with maximum correlations ranging from 0.3 to about 0.6. For streams along the west coast corridor the circulation pattern associated with positive streamflow anomalies is low pressure centered off the coast to the west or northwest, indicative of increased winter storms and an anomalous westerly-to-southwesterly wind component. For streams in the interior positive streamflow anomalies are associated with a positive SLP anomaly stationed remotely over the central North Pacific, and with negative but generally weaker SLP anomalies locally. One important influence on streamflow variability is the strength of the Aleutian Low in winter. This is represented by the familiar Pacific-North America (PNA) index and also by an index defined herein the “CNP” (Central North Pacific). This index, beginning in 1899, is taken to be the average of the SLP anomaly south of the Aleutians and the western Gulf of Alaska. Correlations between PNA or CNP and regional anomalies reflect streamflow the alternations in strength and position of the mean North Pacific storm track entering North America as well as shifts in the trade winds over the subtropical North Pacific. Regions whose streamflow is best tuned to the PNA or CNP include coastal Alaska, the northwestern United States, and Hawaii; the latter two regions have the opposite sign anomaly as the former. The pattern of streamflow variations associated with El Niño is similar, but the El Niño signal also includes a tendency for greater than normal streamflow in the southwestern United States. These indices are significantly correlated with streamflow at one to two seasons in advance of the December–August period, which may allow modestly skillful forecasts. It is important to note that streamflow variability in some areas, such as British Columbia and California, does not respond consistently to these broad scale Pacific atmospheric circulation indices, but is related to regional atmospheric anomaly features over the eastern North Pacific. Spatially, streamflow anomalies are fairly well correlated over scales of several hundred kilometers. Inspection of the spatial anomalies of stream-flow in this study suggest an asymmetry in the spatial pattern of positive versus negative streamflow anomalies in the western United States: dry patterns have tended to be larger and more spatially coherent than wet patterns.

Electrochemical impedance study of the interaction of metal ions with unlabeled PNA.

PubMed

Gao, Lan; Li, Congjuan; Li, Xiaohong; Kraatz, Heinz-Bernhard

2010-09-14

The interactions of the metal ions Mg(2+), Zn(2+), Ni(2+), and Co(2+) with thin films of peptide nucleic acids (PNAs) were studied by electrochemical impedance spectroscopy (EIS), and the results show that Zn(2+), Ni(2+) and Co(2+) interacted favorably with the PNA film involving the backbone and the nucleobases with the exception of Mg(2+) for which the interaction with the backbone appears to be dominant.

Synthesis of Bipartite Tetracysteine PNA Probes for DNA In Situ Fluorescent Labeling.

PubMed

Fang, Ge-Min; Seitz, Oliver

2017-12-24

"Label-free" fluorescent probes that avoid additional steps or building blocks for conjugation of fluorescent dyes with oligonucleotides can significantly reduce the time and cost of parallel bioanalysis of a large number of nucleic acid samples. A method for the synthesis of "label-free" bicysteine-modified PNA probes using solid-phase synthesis and procedures for sequence-specific DNA in situ fluorescent labeling is described here. The concept is based on the adjacent alignment of two bicysteine-modified peptide nucleic acids on a DNA target to form a structurally optimized bipartite tetracysteine motif, which induces a sequence-specific fluorogenic reaction with commercially available biarsenic dyes, even in complex media such as cell lysate. This unit will help researchers to quickly synthesize bipartite tetracysteine PNA probes and carry out low-cost DNA in situ fluorescent labeling experiments. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Cationic Shell-crosslinked Knedel-like (cSCK) Nanoparticles for Highly Efficient PNA Delivery

PubMed Central

Fang, Huafeng; Zhang, Ke; Shen, Gang; Wooley, Karen L.; Taylor, John-Stephen A.

2009-01-01

Peptide nucleic acids have a number of features that make them an ideal platform for the development of in vitro biological probes and tools. Unfortunately, their inability to pass through membranes has limited their in vivo application as diagnostic and therapeutic agents. Herein, we describe the development of cationic shell-crosslinked knedel-like (cSCK) nanoparticles as highly efficient vehicles for the delivery of PNAs into cells, either through electrostatic complexation with a PNA•ODN hybrid, or through a bioreductively cleavable disulfide linkage to a PNA. These delivery systems are better than the standard lipofectamine/ODN-mediated method and much better than the Arg9-mediated method for PNA delivery in HeLa cells, showing lower toxicity and higher bioactivity. The cSCKs were also found to facilitate both endocytosis and endosomal release of the PNAs, while themselves remaining trapped in the endosomes. PMID:19231840

A 1.5 hour procedure for identification of Enterococcus Species directly from blood cultures.

PubMed

Morgan, Margie A; Marlowe, Elizabeth; Novak-Weekly, Susan; Miller, J M; Painter, T M; Salimnia, Hossein; Crystal, Benjamin

2011-02-10

Enterococci are a common cause of bacteremia with E. faecalis being the predominant species followed by E. faecium. Because resistance to ampicillin and vancomycin in E. faecalis is still uncommon compared to resistance in E. faecium, the development of rapid tests allowing differentiation between enterococcal species is important for appropriate therapy and resistance surveillance. The E. faecalis OE PNA FISH assay (AdvanDx, Woburn, MA) uses species-specific peptide nucleic acid (PNA) probes in a fluorescence in situ hybridization format and offers a time to results of 1.5 hours and the potential of providing important information for species-specific treatment. Multicenter studies were performed to assess the performance of the 1.5 hour E. faecalis/OE PNA FISH procedure compared to the original 2.5 hour assay procedure and to standard bacteriology methods for the identification of enterococci directly from a positive blood culture bottle.

A 1.5 Hour Procedure for Identification of Enterococcus Species Directly from Blood Cultures

PubMed Central

Morgan, Margie A.; Marlowe, Elizabeth; Novak-Weekly, Susan; Miller, J.M.; Painter, T.M.; Salimnia, Hossein; Crystal, Benjamin

2011-01-01

Enterococci are a common cause of bacteremia with E. faecalis being the predominant species followed by E. faecium. Because resistance to ampicillin and vancomycin in E. faecalis is still uncommon compared to resistance in E. faecium, the development of rapid tests allowing differentiation between enterococcal species is important for appropriate therapy and resistance surveillance. The E. faecalis OE PNA FISH assay (AdvanDx, Woburn, MA) uses species-specific peptide nucleic acid (PNA) probes in a fluorescence in situ hybridization format and offers a time to results of 1.5 hours and the potential of providing important information for species-specific treatment. Multicenter studies were performed to assess the performance of the 1.5 hour E. faecalis/OE PNA FISH procedure compared to the original 2.5 hour assay procedure and to standard bacteriology methods for the identification of enterococci directly from a positive blood culture bottle. PMID:21339730

In vitro infectivity and differential gene expression of Leishmania infantum metacyclic promastigotes: negative selection with peanut agglutinin in culture versus isolation from the stomodeal valve of Phlebotomus perniciosus.

PubMed

Alcolea, Pedro J; Alonso, Ana; Degayón, María A; Moreno-Paz, Mercedes; Jiménez, Maribel; Molina, Ricardo; Larraga, Vicente

2016-05-20

Leishmania infantum is the protozoan parasite responsible for zoonotic visceral leishmaniasis in the Mediterranean basin. A recent outbreak in humans has been reported in this area. The life cycle of the parasite is digenetic. The promastigote stage develops within the gut of phlebotomine sand flies, whereas amastigotes survive and multiply within phagolysosomes of mammalian host phagocytes. The major vector of L. infantum in Spain is Phlebotomus perniciosus. The axenic culture model of promastigotes is generally used because it is able to mimic the conditions of the natural environment (i.e. the sand fly vector gut). However, infectivity decreases with culture passages and infection of laboratory animals is frequently required. Enrichment of the stationary phase population in highly infective metacyclic promastigotes is achieved by negative selection with peanut agglutinin (PNA), which is possible only in certain Leishmania species such as L. major and L. infantum. In this study, in vitro infectivity and differential gene expression of cultured PNA-negative promastigotes (Pro-PNA(-)) and metacyclic promastigotes isolated from the sand fly anterior thoracic midgut (Pro-Pper) have been compared. In vitro infectivity is about 30 % higher in terms of rate of infected cells and number of amastigotes per infected cell in Pro-Pper than in Pro-PNA(-). This finding is in agreement with up-regulation of a leishmanolysin gene (gp63) and genes involved in biosynthesis of glycosylinositolphospholipids (GIPL), lipophosphoglycan (LPG) and proteophosphoglycan (PPG) in Pro-Pper. In addition, differences between Pro-Pper and Pro-PNA(-) in genes involved in important cellular processes (e.g. signaling and regulation of gene expression) have been found. Pro-Pper are significantly more infective than peanut lectin non-agglutinating ones. Therefore, negative selection with PNA is an appropriate method for isolating metacyclic promastigotes in stationary phase of axenic culture but it does not allow reaching the in vitro infectivity levels of Pro-Pper. Indeed, GIPL, LPG and PPG biosynthetic genes together with a gp63 gene are up-regulated in Pro-Pper and interestingly, the correlation coefficient between both transcriptomes in terms of transcript abundance is R (2) = 0.68. This means that the correlation is sufficiently high to consider that both samples are physiologically comparable (i.e. the experiment was correctly designed and performed) and sufficiently low to conclude that important differences in transcript abundance have been found. Therefore, the implications of axenic culture should be evaluated case-by-case in each experimental design even when the stationary phase population in culture is enriched in metacyclic promastigotes by negative selection with PNA.

Tracking the delayed response of the northern winter stratosphere to ENSO using multi reanalyses and model simulations

NASA Astrophysics Data System (ADS)

Ren, Rongcai; Rao, Jian; Wu, Guoxiong; Cai, Ming

2017-05-01

The concurrent effects of the El Niño-Southern Oscillation (ENSO) on the northern winter stratosphere have been widely recognized; however, the delayed effects of ENSO in the next winter after mature ENSO have yet to be confirmed in multi reanalyses and model simulations. This study uses three reanalysis datasets, a long-term fully coupled model simulation, and a high-top general circulation model to examine ENSO's delayed effects in the stratosphere. The warm-minus-cold composite analyses consistently showed that, except those quick-decaying quasi-biennial ENSO events that reverse signs during July-August-September (JAS) in their decay years, ENSO events particularly those quasi-quadrennial (QQ) that persist through JAS, always have a significant effect on the extratropical stratosphere in both the concurrent winter and the next winter following mature ENSO. During the concurrent winter, the QQ ENSO-induced Pacific-North American (PNA) pattern corresponds to an anomalous wavenumber-1 from the upper troposphere to the stratosphere, which acts to intensify/weaken the climatological wave pattern during warm/cold ENSO. Associated with the zonally quasi-homogeneous tropical forcing in spring of the QQ ENSO decay years, there appear persistent and zonally quasi-homogeneous temperature anomalies in the midlatitudes from the upper troposphere to the lower stratosphere until summer. With the reduction in ENSO forcing and the PNA responses in the following winter, an anomalous wavenumber-2 prevails in the extratropics. Although the anomalous wave flux divergence in the upper stratospheric layer is still dominated by wavenumber-1, it is mainly caused by wavenumber-2 in the lower stratosphere. However, the wavenumber-2 activity in the next winter is always underestimated in the model simulations, and wavenumber-1 activity dominates in both winters.

Optofluidic plasmonic onchip nanosensor array for biodetection

NASA Astrophysics Data System (ADS)

Huang, Min

Surface plasmon resonance (SPR) sensing has been demonstrated in the past decade to be the gold standard technique for biochemical interaction analysis, and plays an important role in drug discovery and biomedical research. The technique circumvents the need of fluorescence/radioactive tagging or enzymatic detection, enables ultrasensitive remote sensing, and quantitatively monitors bio-interaction in real time. Although SPR has these attractive features that can satisfy most research/clinic requirements, there still exist problems that limit its applications. First, the reflection geometry of the prism coupling scheme adds limitations for high throughput screening application. Additionally, SPR instrumentations are bulky and not suitable for point-of-care settings. Moreover, the SPR sensor is embedded in conventional micro-fluidic cells, in which the sensor performance is limited by inefficient analyte transport. Suspended plasmonic nanohole array (PNA) offers an opportunity to overcome these limitations. A collinear excitation/collection coupling scheme combined with the small footprint of PNA provides unique platform for multiplexing and system minimization. The suspended nanohole structure also offers a unique configuration to integrate nano-photonics with nano-fluidics. This thesis focuses on developing a lab-on-a-chip PNA platform for point-of-care bio-detection. To achieve this, we first demonstrate that the figure-of-merit of our PNA sensor surpasses that of the prism coupled SPR. We also show that the ultrasensitive label-free PNA sensor is able to directly detect intact viruses from biological media at clinically relevant concentrations with little sample preparation. We then present a plasmonic microarray with over one million PNA sensors on a microscope slide for high throughput screening applications. A dual-color filter imaging method is introduced to increase the accuracy, reliability, and signal-to-noise ratio in a highly multiplexed manner. Finally, we present a nanoplasmonic-nanofluidic platform enabling active delivery of analyte to the sensor. Sensor response time is reduced by an order of magnitude compared to the conventional flow scheme. A dynamic range spanning 5 orders of magnitude from 103 to 107 particles/mL is shown on this platform corresponding to analyte concentration sufficient for clinical applications. The proposed approach opens up opportunities of a lab-on-a-chip bio-detection system for drug screening, disease diagnostic as well as clinic studies.

Disruption of Saturn's quasi-periodic equatorial oscillation by the great northern storm

NASA Astrophysics Data System (ADS)

Fletcher, Leigh N.; Guerlet, Sandrine; Orton, Glenn S.; Cosentino, Richard G.; Fouchet, Thierry; Irwin, Patrick G. J.; Li, Liming; Flasar, F. Michael; Gorius, Nicolas; Morales-Juberías, Raúl

2017-11-01

The equatorial middle atmospheres of the Earth1, Jupiter2 and Saturn3,4 all exhibit a remarkably similar phenomenon—a vertical, cyclic pattern of alternating temperatures and zonal (east-west) wind regimes that propagate slowly downwards with a well-defined multi-year period. Earth's quasi-biennial oscillation (QBO) (observed in the lower stratospheric winds with an average period of 28 months) is one of the most regular, repeatable cycles exhibited by our climate system1,5,6, and yet recent work has shown that this regularity can be disrupted by events occurring far away from the equatorial region, an example of a phenomenon known as atmospheric teleconnection7,8. Here, we reveal that Saturn's equatorial quasi-periodic oscillation (QPO) (with an 15-year period3,9) can also be dramatically perturbed. An intense springtime storm erupted at Saturn's northern mid-latitudes in December 201010-12, spawning a gigantic hot vortex in the stratosphere at 40° N that persisted for three years13. Far from the storm, the Cassini temperature measurements showed a dramatic 10 K cooling in the 0.5-5 mbar range across the entire equatorial region, disrupting the regular QPO pattern and significantly altering the middle-atmospheric wind structure, suggesting an injection of westward momentum into the equatorial wind system from waves generated by the northern storm. Hence, as on Earth, meteorological activity at mid-latitudes can have a profound effect on the regular atmospheric cycles in Saturn's tropics, demonstrating that waves can provide horizontal teleconnections between the phenomena shaping the middle atmospheres of giant planets.

Variations in the correlation between teleconnections and Taiwan's streamflow

NASA Astrophysics Data System (ADS)

Chen, Chia-Jeng; Lee, Tsung-Yu

2017-07-01

Interannual variations in catchment streamflow represent an integrated response to anomalies in regional moisture transport and atmospheric circulations and are ultimately linked to large-scale climate oscillations. This study conducts correlation analysis to calculate how summertime (July-September, JAS) streamflow data derived at 28 upstream and 13 downstream gauges in Taiwan correlate with 14 teleconnection indices in the current or preceding seasons. We find that the western Pacific (WP) and Pacific-Japan (PJ) patterns, both of which play a critical role in determining cyclonic activity in the western North Pacific basin, exhibit the highest concurrent correlations (most significant r = 0. 50) with the JAS flows in Taiwan. Alternatively, the Quasi-Biennial Oscillation (QBO) averaged over the period from the previous October to June of the current year is significantly correlated with the JAS flows (most significant r = -0. 66), indicating some forecasting utility. By further examining the correlation results using a 20-year moving window, peculiar temporal variations and possible climate regime shifts (CRSs) can be revealed. A CRS test is employed to identify suspicious and abrupt changes in the correlation. The late 1970s and 1990s are identified as two significant change points. During the intermediate period, Taiwan's streamflow and the PJ index exhibit a marked in-phase relationship (r > 0. 8). It is verified that the two shifts are in concordance with the alteration of large-scale circulations in the Pacific basin by investigating the changes in pattern correlation and composite maps before and after the change point. Our results suggest that empirical forecasting techniques should take into account the effect of CRSs on predictor screening.

Polynitroxyl albumin and albumin therapy after pediatric asphyxial cardiac arrest: effects on cerebral blood flow and neurologic outcome

PubMed Central

Manole, Mioara D; Kochanek, Patrick M; Foley, Lesley M; Hitchens, T Kevin; Bayır, Hülya; Alexander, Henry; Garman, Robert; Ma, Li; Hsia, Carleton J C; Ho, Chien; Clark, Robert S B

2012-01-01

Postresuscitation cerebral blood flow (CBF) disturbances and generation of reactive oxygen species likely contribute to impaired neurologic outcome after pediatric cardiac arrest (CA). Hence, we determined the effects of the antioxidant colloid polynitroxyl albumin (PNA) versus albumin or normal saline (NS) on CBF and neurologic outcome after asphyxial CA in immature rats. We induced asphyxia for 9 minutes in male and female postnatal day 16 to 18 rats randomized to receive PNA, albumin, or NS at resuscitation from CA or sham surgery. Regional CBF was measured serially from 5 to 150 minutes after resuscitation by arterial spin-labeled magnetic resonance imaging. We assessed motor function (beam balance and inclined plane), spatial memory retention (water maze), and hippocampal neuronal survival. Polynitroxyl albumin reduced early hyperemia seen 5 minutes after CA. In contrast, albumin markedly increased and prolonged hyperemia. In the delayed period after resuscitation (90 to 150 minutes), CBF was comparable among groups. Both PNA- and albumin-treated rats performed better in the water maze versus NS after CA. This benefit was observed only in males. Hippocampal neuron survival was similar between injury groups. Treatment of immature rats with PNA or albumin resulted in divergent acute changes in CBF, but both improved spatial memory retention in males after asphyxial CA. PMID:22126915

Comparative analysis of Gram's stain, PNA-FISH and Sepsityper with MALDI-TOF MS for the identification of yeast direct from positive blood cultures.

PubMed

Gorton, Rebecca L; Ramnarain, P; Barker, K; Stone, N; Rattenbury, S; McHugh, T D; Kibbler, C C

2014-10-01

Fungaemia diagnosis could be improved by reducing the time to identification of yeast from blood cultures. This study aimed to evaluate three rapid methods for the identification of yeast direct from blood cultures; Gram's stain analysis, the AdvanDX Peptide Nucleic Acid in Situ Hybridisation Yeast Traffic Light system (PNA-FISH YTL) and Bruker Sepsityper alongside matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-TOF MS). Fifty blood cultures spiked with a known single yeast strain were analysed by blinded operators experienced in each method. Identifications were compared with MALDI-TOF MS CHROMagar Candida culture and ITS rRNA sequence-based identifications. On first attempt, success rates of 96% (48/50) and 76% (36/50) were achieved using PNA-FISH YTL and Gram's stain respectively. MALDI-TOF MS demonstrated a success rate of 56% (28/50) when applying manufacturer's species log score thresholds and 76% (38/50) using in-house parameters, including lowering the species log score threshold to >1.5. In conclusion, PNA-FISH YTL demonstrated a high success rate successfully identifying yeast commonly encountered in fungaemia. Sepsityper(™) with MALDI-TOF MS was accurate but increased sensitivity is required. Due to the misidentification of commonly encountered yeast Gram's stain analysis demonstrated limited utility in this setting. © 2014 Blackwell Verlag GmbH.

Effects of gestational length, gender, postnatal age, and birth order on visual contrast sensitivity in infants.

PubMed

Dobkins, Karen R; Bosworth, Rain G; McCleery, Joseph P

2009-09-30

To investigate effects of visual experience versus preprogrammed mechanisms on visual development, we used multiple regression analysis to determine the extent to which a variety of variables (that differ in the extent to which they are tied to visual experience) predict luminance and chromatic (red/green) contrast sensitivity (CS), which are mediated by the magnocellular (M) and parvocellular (P) subcortical pathways, respectively. Our variables included gestational length (GL), birth weight (BW), gender, postnatal age (PNA), and birth order (BO). Two-month-olds (n = 60) and 6-month-olds (n = 122) were tested. Results revealed that (1) at 2 months, infants with longer GL have higher luminance CS; (2) at both ages, CS significantly increases over a approximately 21-day range of PNA, but this effect is stronger in 2- than 6-month-olds and stronger for chromatic than luminance CS; (3) at 2 months, boys have higher luminance CS than girls; and (4) at 2 months, firstborn infants have higher CS, while at 6 months, non-firstborn infants have higher CS. The results for PNA/GL are consistent with the possibility that P pathway development is more influenced by variables tied to visual experience (PNA), while M pathway development is more influenced by variables unrelated to visual experience (GL). Other variables, including prenatal environment, are also discussed.

A non-covalent peptide-based strategy for ex vivo and in vivo oligonucleotide delivery.

PubMed

Crombez, Laurence; Morris, May C; Heitz, Frederic; Divita, Gilles

2011-01-01

The dramatic acceleration in identification of new nucleic acid-based therapeutic molecules such as short interfering RNA (siRNA) and peptide-nucleic acid (PNA) analogues has provided new perspectives for therapeutic targeting of specific genes responsible for pathological disorders. However, the poor cellular uptake of nucleic acids together with the low permeability of the cell membrane to negatively charged molecules remain major obstacles to their clinical development. Several non-viral strategies have been proposed to improve the delivery of synthetic short oligonucleotides both in cultured cells and in vivo. Cell-penetrating peptides constitute very promising tools for non-invasive cellular import of oligonucleotides and analogs. We recently described a non-covalent strategy based on short amphiphatic peptides (MPG8/PEP3) that have been successfully applied ex vivo and in vivo for the delivery of therapeutic siRNA and PNA molecules. PEP3 and MPG8 form stable nanoparticles with PNA analogues and siRNA, respectively, and promote their efficient cellular uptake, independently of the endosomal pathway, into a wide variety of cell lines, including primary and suspension lines, without any associated cytotoxicity. This chapter describes easy-to-handle protocols for the use of MPG-8 or PEP-3-nanoparticle technologies for PNA and siRNA delivery into adherent and suspension cell lines as well as in vivo into cancer mouse models.

Effects of gestational length, gender, postnatal age, and birth order on visual contrast sensitivity in infants

PubMed Central

Dobkins, Karen R.; Bosworth, Rain G.; McCleery, Joseph P.

2010-01-01

To investigate effects of visual experience versus preprogrammed mechanisms on visual development, we used multiple regression analysis to determine the extent to which a variety of variables (that differ in the extent to which they are tied to visual experience) predict luminance and chromatic (red/green) contrast sensitivity (CS), which are mediated by the magnocellular (M) and parvocellular (P) subcortical pathways, respectively. Our variables included gestational length (GL), birth weight (BW), gender, postnatal age (PNA), and birth order (BO). Two-month-olds (n = 60) and 6-month-olds (n = 122) were tested. Results revealed that (1) at 2 months, infants with longer GL have higher luminance CS; (2) at both ages, CS significantly increases over a ~21-day range of PNA, but this effect is stronger in 2- than 6-month-olds and stronger for chromatic than luminance CS; (3) at 2 months, boys have higher luminance CS than girls; and (4) at 2 months, firstborn infants have higher CS, while at 6 months, non-firstborn infants have higher CS. The results for PNA/GL are consistent with the possibility that P pathway development is more influenced by variables tied to visual experience (PNA), while M pathway development is more influenced by variables unrelated to visual experience (GL). Other variables, including prenatal environment, are also discussed. PMID:19810800

Summer precipitation variability over South America on long and short intraseasonal timescales

NASA Astrophysics Data System (ADS)

Gonzalez, Paula L. M.; Vera, Carolina S.

2014-10-01

A dipole pattern in convection between the South Atlantic convergence zone and the subtropical plains of southeastern South America characterizes summer intraseasonal variability over the region. The dipole pattern presents two main bands of temporal variability, with periods between 10 and 30 days, and 30 and 90 days; each influenced by different large-scale dynamical forcings. The dipole activity on the 30-90-day band is related to an eastward traveling wavenumber-1 structure in both OLR and circulation anomalies in the tropics, similar to that associated with the Madden-Julian oscillation. The dipole is also related to a teleconnection pattern extended along the South Pacific between Australia and South America. Conversely, the dipole activity on the 10-30-day band does not seem to be associated with tropical convection anomalies. The corresponding circulation anomalies exhibit, in the extratropics, the structure of Rossby-like wave trains, although their sources are not completely clear.

Teleconnections of ENSO and IOD to summer monsoon and rice production potential of India

NASA Astrophysics Data System (ADS)

Jha, Somnath; Sehgal, Vinay Kumar; Raghava, Ramesh; Sinha, Mourani

2016-12-01

Regional trend of summer monsoon precipitation has been analyzed for broad physical regions of India namely, (i) Indo-Gangetic plain, (ii) Central and East India, (iii) Coastal and Peninsular India and (iv) Western India. A significantly drying trend has been found in the two regions namely, Indo-Gangetic plain and Central and East India with comparative seasonal rate of drying higher in the latter region. A complex relation between the regional trend of summer monsoon precipitation, global teleconnection parameters and rice production of the regions have been studied. El Niño-Southern Oscillation (ENSO) and Indian Ocean dipole (IOD) have a significant role in the precipitation anomaly of Indo-Gangetic plain unlike Central and East India where the ENSO only plays role as global teleconnection parameter. Rice production of Central and East India has been found to be affected adversely during the El Nino years. Central and East India is found to be the worst affected region compared to the Indo-Gangetic plain with respect to its fragile rainfed rice production potential and strong adverse teleconnection of El Nino on the rice production in this zone.

The role of the basic state in the ENSO-monsoon relationship and implications for predictability

NASA Astrophysics Data System (ADS)

Turner, A. G.; Inness, P. M.; Slingo, J. M.

2005-04-01

The impact of systematic model errors on a coupled simulation of the Asian summer monsoon and its interannual variability is studied. Although the mean monsoon climate is reasonably well captured, systematic errors in the equatorial Pacific mean that the monsoon-ENSO teleconnection is rather poorly represented in the general-circulation model. A system of ocean-surface heat flux adjustments is implemented in the tropical Pacific and Indian Oceans in order to reduce the systematic biases. In this version of the general-circulation model, the monsoon-ENSO teleconnection is better simulated, particularly the lag-lead relationships in which weak monsoons precede the peak of El Niño. In part this is related to changes in the characteristics of El Niño, which has a more realistic evolution in its developing phase. A stronger ENSO amplitude in the new model version also feeds back to further strengthen the teleconnection. These results have important implications for the use of coupled models for seasonal prediction of systems such as the monsoon, and suggest that some form of flux correction may have significant benefits where model systematic error compromises important teleconnections and modes of interannual variability.

Natural climate variability and teleconnections to precipitation over the Pacific-North American region in CMIP3 and CMIP5 models

NASA Astrophysics Data System (ADS)

Polade, Suraj D.; Gershunov, Alexander; Cayan, Daniel R.; Dettinger, Michael D.; Pierce, David W.

2013-05-01

climate variability will continue to be an important aspect of future regional climate even in the midst of long-term secular changes. Consequently, the ability of climate models to simulate major natural modes of variability and their teleconnections provides important context for the interpretation and use of climate change projections. Comparisons reported here indicate that the CMIP5 generation of global climate models shows significant improvements in simulations of key Pacific climate mode and their teleconnections to North America compared to earlier CMIP3 simulations. The performance of 14 models with simulations in both the CMIP3 and CMIP5 archives are assessed using singular value decomposition analysis of simulated and observed winter Pacific sea surface temperatures (SSTs) and concurrent precipitation over the contiguous United States and northwestern Mexico. Most of the models reproduce basic features of the key natural mode and their teleconnections, albeit with notable regional deviations from observations in both SST and precipitation. Increasing horizontal resolution in the CMIP5 simulations is an important, but not a necessary, factor in the improvement from CMIP3 to CMIP5.

Natural climate variability and teleconnections to precipitation over the Pacific-North American region in CMIP3 and CMIP5 models

USGS Publications Warehouse

Polade, Suraj D.; Gershunov, Alexander; Cayan, Daniel R.; Dettinger, Michael D.; Pierce, David W.

2013-01-01

Natural climate variability will continue to be an important aspect of future regional climate even in the midst of long-term secular changes. Consequently, the ability of climate models to simulate major natural modes of variability and their teleconnections provides important context for the interpretation and use of climate change projections. Comparisons reported here indicate that the CMIP5 generation of global climate models shows significant improvements in simulations of key Pacific climate mode and their teleconnections to North America compared to earlier CMIP3 simulations. The performance of 14 models with simulations in both the CMIP3 and CMIP5 archives are assessed using singular value decomposition analysis of simulated and observed winter Pacific sea surface temperatures (SSTs) and concurrent precipitation over the contiguous United States and northwestern Mexico. Most of the models reproduce basic features of the key natural mode and their teleconnections, albeit with notable regional deviations from observations in both SST and precipitation. Increasing horizontal resolution in the CMIP5 simulations is an important, but not a necessary, factor in the improvement from CMIP3 to CMIP5.

Model-based clinical dose optimization for phenobarbital in neonates: An illustration of the importance of data sharing and external validation.

PubMed

Völler, Swantje; Flint, Robert B; Stolk, Leo M; Degraeuwe, Pieter L J; Simons, Sinno H P; Pokorna, Paula; Burger, David M; de Groot, Ronald; Tibboel, Dick; Knibbe, Catherijne A J

2017-11-15

Particularly in the pediatric clinical pharmacology field, data-sharing offers the possibility of making the most of all available data. In this study, we utilize previously collected therapeutic drug monitoring (TDM) data of term and preterm newborns to develop a population pharmacokinetic model for phenobarbital. We externally validate the model using prospective phenobarbital data from an ongoing pharmacokinetic study in preterm neonates. TDM data from 53 neonates (gestational age (GA): 37 (24-42) weeks, bodyweight: 2.7 (0.45-4.5) kg; postnatal age (PNA): 4.5 (0-22) days) contained information on dosage histories, concentration and covariate data (including birth weight, actual weight, post-natal age (PNA), postmenstrual age, GA, sex, liver and kidney function, APGAR-score). Model development was carried out using NONMEM ® 7.3. After assessment of model fit, the model was validated using data of 17 neonates included in the DINO (Drug dosage Improvement in NeOnates)-study. Modelling of 229 plasma concentrations, ranging from 3.2 to 75.2mg/L, resulted in a one compartment model for phenobarbital. Clearance (CL) and volume (V d ) for a child with a birthweight of 2.6kg at PNA day 4.5 was 0.0091L/h (9%) and 2.38L (5%), respectively. Birthweight and PNA were the best predictors for CL maturation, increasing CL by 36.7% per kg birthweight and 5.3% per postnatal day of living, respectively. The best predictor for the increase in V d was actual bodyweight (0.31L/kg). External validation showed that the model can adequately predict the pharmacokinetics in a prospective study. Data-sharing can help to successfully develop and validate population pharmacokinetic models in neonates. From the results it seems that both PNA and bodyweight are required to guide dosing of phenobarbital in term and preterm neonates. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Prenatal Androgen Exposure Causes Hypertension and Gut Microbiota Dysbiosis.

PubMed

Sherman, Shermel; Sarsour, Nadeen; Salehi, Marziyeh; Schroering, Allen; Mell, Blair; Joe, Bina; Hill, Jennifer W

2018-02-22

Conditions of excess androgen in women, such as polycystic ovary syndrome (PCOS), often exhibit intergenerational transmission. One way in which the risk for PCOS may be increased in daughters of affected women is through exposure to elevated androgens in utero. Hyperandrogenemic conditions have serious health consequences, including increased risk for hypertension and cardiovascular disease. Recently, gut dysbiosis has been found to induce hypertension in rats, such that blood pressure can be normalized through fecal microbial transplant. Therefore, we hypothesized that the hypertension seen in PCOS has early origins in gut dysbiosis caused by in utero exposure to excess androgen. We investigated this hypothesis with a model of prenatal androgen (PNA) exposure and maternal hyperandrogenemia by single-injection of testosterone cypionate or sesame oil vehicle (VEH) to pregnant dams in late gestation. We then completed a gut microbiota and cardiometabolic profile of the adult female offspring. The metabolic assessment revealed that adult PNA rats had increased body weight and increased mRNA expression of adipokines: adipocyte binding protein 2, adiponectin, and leptin in inguinal white adipose tissue. Radiotelemetry analysis revealed hypertension with decreased heart rate in PNA animals. The fecal microbiota profile of PNA animals contained higher relative abundance of bacteria associated with steroid hormone synthesis, Nocardiaceae and Clostridiaceae, and lower abundance of Akkermansia, Bacteroides, Lactobacillus, Clostridium. The PNA animals also had an increased relative abundance of bacteria associated with biosynthesis and elongation of unsaturated short chain fatty acids (SCFAs). We found that prenatal exposure to excess androgen negatively impacted cardiovascular function by increasing systolic and diastolic blood pressure and decreasing heart rate. Prenatal androgen was also associated with gut microbial dysbiosis and altered abundance of bacteria involved in metabolite production of short chain fatty acids. These results suggest that early-life exposure to hyperandrogenemia in daughters of women with PCOS may lead to long-term alterations in gut microbiota and cardiometabolic function.

Accidentes laborales asociados al desánimo de médicos SERUMS para laborar en el primer nivel de atención de Lima, Perú

PubMed Central

Mejia, Christian R.; Valladares-Garrido, Mario J.; Romero, Brian M.; Valladares-Garrido, Danai; Linares-Reyes, Edgardo

2018-01-01

Introducción la retención laboral es un tema de suma importancia, porque se requiere de profesionales en el primer nivel de atención (PNA). El objetivo fue determinar si los accidentes laborales se asociaron al desánimo de los médicos para trabajar en el PNA de Lima, Perú. Métodos estudio transversal analítico de datos secundarios de una base de datos generada de una encuesta a médicos que realizaron su Servicio Rural y Urbano-Marginal en Salud (SERUMS). Se incluyó solo a los médicos que manifestaron al inicio del SERUMS que podían trabajar en el PNA de Lima. Se definió como cambio de intención de trabajo en el PNA a los que finalizando el SERUMS refirieron que ya no deseaban laborar en Lima. Esto se asoció según si tuvieron un accidente laboral y se ajustó por otras variables. Resultados de los 124 médicos el 63% fueron hombres (78). La mediana de edad fue de 26 años (rango intercuartílico: 25-27 años). Después de su SERUMS, el 12% (15) manifestó que cambió su interés y que deseaba trabajar en la capital. En el análisis multivariado, haber tenido un accidente laboral disminuyó la frecuencia del cambio de intención de trabajo en el PNA (RPa: 0.28, IC 95%: 0.14-0.54, p < 0,001), ajustado por ocho variables. Conclusiones en un estudio previo los accidentes laborales disminuyeron la frecuencia de trabajar en provincias, pero nuestro estudio dice lo contrario, posiblemente por la percepción de que un trabajo en la capital del país permite estar más cerca de los servicios para ser atendido en caso de cualquier emergencia. PMID:29190859

Remote Enantioselection Transmitted by an Achiral Peptide Nucleic Acid Backbone

NASA Technical Reports Server (NTRS)

Kozlov, Igor A.; Orgel, Leslie E.; Nielsen, Peter E.

2000-01-01

short homochiral segment of DNA into a PNA helix could have guaranteed that the next short segment of DNA to be incorporated would have the same handedness as the first. Once two segments of the same handedness were present, the probability that a third segment would have the same handedness would increase, and so on. Evolution could then slowly dilute out the PNA part. This scenario would ultimately allow the formation of a chiral oligonucleotide by processes that are largely resistant to enantiomeric crossinhibition. It is important to note that the ligation of homochiral dinucleotides on a nucleic acid template would probably be at least as enantiospecific as the reaction that we have studied. The disadvantage of using chiral monomers as components of a replicating system arises from the difficulty of generating a first long homochiral template from a racemic mixture of monomers, although results of experiments designed to overcome this difficulty by employing homochiral tetramers have been reported.l l The probability of obtaining a homochiral n-mer from achiral substrates is approximately 1P-I if the nontemplate-directed extension of the primer is not enantioselective. Hence, it would be very hard to get started with a homochiral 40-mer, for example. No such difficulty exists in a scenario that originates with an achiral genetic material and in which the incorporation of very few chiral monomers in this achiral background gradually progresses towards homochirality. It seems possible that some PNA sequences could act as catalysts, analogous to ribozymes, even though PNA lacks clear metal binding sites. Although such catalysts could not be enantioselective, the incorporation of as few as two chiral nucleotides could then impose chiral specificity on the system. Furthermore, such patch chimeras could help to bridge the gap in catalytic potential between PNA and RNA, while guaranteeing enantioselectivity.

Conformational flexibility and packing plausibility of repaglinide polymorphs

NASA Astrophysics Data System (ADS)

Rani, Dimpy; Goyal, Parnika; Chadha, Renu

2018-04-01

The present manuscript highlights the structural insight into the repaglinide polymorphs. The experimental screening for the possible crystal forms were carried out using various solvents, which generated three forms. The crystal structure of Form II and III was determined using PXRD pattern whereas structural analysis of Form I has already been reported. Form I, II and II was found to exist in P212121, PNA21 and P21/c space groups respectively. Conformational analysis was performed to account the conformational flexibility of RPG. The obtained conformers were further utilized to obtain the information about the crystal packing pattern of RPG polymorphs by polymorph prediction module. The lattice energy landscape, depicting the relationship between lattice energy and density of the polymorphs has been obtained for various possible polymorphs. The experimentally isolated polymorphs were successfully fitted into lattice energy landscape.

The synoptic- and planetary-scale environments associated with significant 1000-hPa geostrophic wind events along the Beaufort Sea coast

NASA Astrophysics Data System (ADS)

Cooke, Melanie

The substantial interannual variability and the observed warming trend of the Beaufort Sea region are important motivators for the study of regional climate and weather there. In an attempt to further our understanding of strong wind events, which can drive sea ice dynamics and storm surges, their characteristic environments at the synoptic and planetary scales are defined and analysed using global reanalysis data. A dependency on an enhanced or suppressed Aleutian low is found. This produces either a strong southeasterly or north-westerly 1000-hPa geostrophic wind event. The characteristic mid-tropospheric patterns for these two distinct event types show similarities to the positive and negative Pacific/North American teleconnection patterns, but their correlations have yet to be assessed.

The East Asian Jet Stream and Asian-Pacific Climate

NASA Technical Reports Server (NTRS)

Yang, Song; Lau, K.-M.; Kim, K.-M.

1999-01-01

In this study, the NASA GEOS and NCEP/NCAR reanalyses and GPCP rainfall data have been used to study the variability of the East Asian westerly jet stream and its impact on the Asian-Pacific climate, with a focus on interannual time scales. Results indicate that external forcings such as sea surface temperature (SST) and land surface processes also play an important role in the variability of the jet although this variability is strongly governed by internal dynamics. There is a close link between the jet and Asian-Pacific climate including the Asian winter monsoon and tropical convection. The atmospheric teleconnection pattern associated with the jet is different from the ENSO-related pattern. The influence of the jet on eastern Pacific and North American climate is also discussed.

Teleconnections in complex human-Earth system models

NASA Astrophysics Data System (ADS)

Calvin, K. V.; Edmonds, J.

2017-12-01

Human systems and physical Earth systems are closely coupled and interact in complex ways that are sometimes surprising. This presentation discusses a few examples of system interactions. We consider the coupled energy-water-land-economy systems. We show how reductions in fossil fuel emissions are inversely coupled to land rents, food prices and deforestation. We discuss how water shortages in one part of the world is propagated to other distant parts of the world. We discuss the sensitivity of international trade patterns to energy and land systems technology and markets, and the potentially unanticipated results that can emerge.

Lectin histochemistry as a tool to identify apoptotic cells in the seminiferous epithelium of Syrian hamster (Mesocricetus auratus) subjected to short photoperiod.

PubMed

Seco-Rovira, V; Beltrán-Frutos, E; Ferrer, C; Sánchez-Huertas, M M; Madrid, J F; Saez, F J; Pastor, L M

2013-12-01

Lectins have been widely used to study the pattern of cellular glycoconjugates in numerous species. In the process of cellular apoptosis, it has been observed that changes occur in the membrane sugar sequences of these apoptotic cells. The aim of our work was to identify which lectins, out of an extensive battery of the same (PNA, SBA, HPA, LTA, Con-A, UEA-I, WGA, DBA, MAA, GNA, AAA, SNA), show affinity for germinal cells in apoptosis, at what stage of cell death they do so and in which germinal cell types they can be detected. For this, we studied testis sections during testicular regression in Syrian hamster (Mesocricetus auratus) subjected to short photoperiod. Several lectins showed an affinity for the glycoconjugate residues of germ cells in apoptosis: Gal β1,3-GalNAcα1, α-d-mannose, N-acetylgalactosamine and l-fucose. Furthermore, lectin specificity was observed for some specific germinal cells and in certain stages of apoptosis. It was also observed that one of these lectins (PNA) showed affinity for Sertoli cells undergoing apoptosis. Therefore, we conclude that the use of lectin histochemistry could be a very useful tool for studying apoptosis in the seminiferous epithelium because of the specificity shown towards germinal cells in pathological or experimentally induced epithelial depletion models. © 2013 Blackwell Verlag GmbH.

Trans-Pacific ENSO teleconnections pose a correlated risk to global agriculture

NASA Astrophysics Data System (ADS)

Anderson, W. B.; Seager, R.; Cane, M. A.; Baethgen, W.

2017-12-01

The El Niño Southern Oscillation (ENSO) is a major source of interannual climate variability, particularly in the Pacific Basin. ENSO life-cycles tend to evolve over multiple years, as do the associated trans-Pacific ENSO teleconnections. This analysis, however, represents the first attempt to characterize the structure of the risk posed by ENSO to wheat, maize and soybean production across the Pacific Basin. Our results indicate that most ENSO teleconnections relevant for crop flowering seasons are the result of a single trans-Pacific circulation anomaly that develops in boreal summer and persists through the spring. During the late summer and early fall of a developing ENSO event, the tropical Pacific forces an atmospheric anomaly in the midlatitudes that spans the Pacific Basin. This teleconnection directly links the soybean and maize growing seasons of the US, Mexico and China. It also connects the wheat growing seasons of Argentina, southern Brazil and Australia. The ENSO event peaks in boreal winter, when the atmospheric circulation anomalies intensify and affect maize and soybeans in southeast South America. As the event decays, the ENSO-induced circulation anomalies persist through the wheat flowering seasons in China and the US. While the prospect of ENSO forcing simultaneous droughts in major food producing regions seems disastrous, there may be a silver lining from the perspective of global food security: trans-Pacific ENSO teleconnections to yields are often offsetting between major producing regions in the eastern and western portions of the Pacific Basin. El Niños tend to create good maize and soybean growing conditions in the US and southeast South America, but poor growing conditions in China, Mexico and northeast Brazil. The opposite is true during La Niña. Wheat growing conditions in southeast South America generally have the opposite sign of those in Australia. Finally, we investigate how trade networks interact with this structure of ENSO teleconnections to influence food security. Global trade may shift the burden of poor growing conditions onto import-dependent countries if multiple exporting nations experience crop failures simultaneously. But trade may also mitigate food security crises if shortfalls from one major producing region are compensated by good harvests elsewhere.

The unusual wet summer (July) of 2014 in Southern Europe

NASA Astrophysics Data System (ADS)

Ratna, Satyaban B.; Ratnam, J. V.; Behera, Swadhin K.; Cherchi, Annalisa; Wang, Wanqiu; Yamagata, Toshio

2017-06-01

Southern Europe (Italy and the surrounding countries) experienced an unusual wet summer in 2014. The monthly rainfall in July 2014 was 84% above (more than three standard deviation) normal with respect to the 1982-2013 July climatology. The heavy rainfall damaged agriculture, and affected tourism and overall economy of the region. In this study, we tried to understand the physical mechanisms responsible for such abnormal weather by using model and observed datasets. The anomalously high precipitation over Italy is found to be associated with the positive sea surface temperature (SST) and convective anomalies in the tropical Pacific through the atmospheric teleconnection. Rossby wave activity flux at upper levels shows an anomalous tropospheric quasi-stationary Rossby wave from the Pacific with an anomalous cyclonic phase over southern Europe. This anomalous cyclonic circulation is barotropic in nature and seen extending to lower atmospheric levels, weakening the seasonal high and causing heavy precipitation over the Southern Europe. The hypothesis is verified using the National Centers for Environmental Prediction (NCEP) coupled forecast system model (CFSv2) seasonal forecasts. It is found that two-month lead forecast of CFSv2 was able to capture the wet summer event of 2014 over Southern Europe. The teleconnection pattern from Pacific to Southern Europe was also forecasted realistically by the CFSv2 system.

ENSO variability over the last 2000 years from a sub-decadal lacustrine lipid biomarker record from Isabel Island, Mexico

NASA Astrophysics Data System (ADS)

Sachse, D.; Romero, L.; Kienel, U.; Haug, G. H.

2016-12-01

ENSO is one of the major drivers of inter-annual climate variability and its effects extend far beyond the Tropical Pacific. However, our knowledge about the stability and linearity of ENSO teleconnections is limited due to the short temporal coverage of observational data, in particular of well dated paleo-ENSO records. Here we present a high-resolution record of rainfall variability on the Pacific coast of Mexico, which today is significantly correlated to ENSO variability (NINO 3.4 index), with dryer conditions during an El Niño phase and wetter conditions during a La Niña phase. The lake, situated in a volcanic crater on Isabel Island, is strongly influenced by rainfall intensity, i.e. freshwater and saline sea water input. A halophile bacterial community dominates during dry phases and an algal community dominates in a freshwater lens which develops during the wet season. Specific lipid biomarkers in the sediments indicate the dominant bacterial community (tetrahymanol and long-chain diols, respectively) in an annually laminated sediment core and record the timing and direction of ENSO mean state changes. We find the region was dry before 825 AD, indicating dominant El Niño. Between 825 and 950 AD, wetter conditions provide evidence for a dominating La Niña like pattern. During the early Medieval Climate Anomaly (MCA, 925-1100 AD) we reconstruct a dryer (El Niño like) environment, changing into a La Niña dominated pattern, prevailing until 1700 AD. The late Little Ice Age (LIA, 1700-1850AD) was initially dry and changed into a wetter climate at 1750 AD. Afterwards El Niño dominated in the region. The overall pattern of these changes agrees with other paleoclimate records from the Pacific region. However, our well dated (±20 years) high-resolution record identifies a number of short-lived episodes of deviations from this pattern, in particular during the MCA and the LIA. We also find strong similarities in the timing of these episodes with North Pacific and North Atlantic records, indicating that ENSO-Northern Hemisphere teleconnections existed throughout the last 2000 years. We find that changes in ENSO pattern during the MCA and the LIA predate changes in the Northern Hemisphere, indicating that ENSO changes affected atmospheric circulation patterns and so directly influenced Northern hemispheric climate.

Template switching between PNA and RNA oligonucleotides

NASA Technical Reports Server (NTRS)

Bohler, C.; Nielsen, P. E.; Orgel, L. E.; Miller, S. L. (Principal Investigator)

1995-01-01

The origin of the RNA world is not easily understood, as effective prebiotic syntheses of the components of RNA, the beta-ribofuranoside-5'-phosphates, are hard to envisage. Recognition of this difficulty has led to the proposal that other genetic systems, the components of which are more easily formed, may have preceded RNA. This raises the question of how transitions between one genetic system and another could occur. Peptide nucleic acid (PNA) resembles RNA in its ability to form double-helical complexes stabilized by Watson-Crick hydrogen bonding between adenine and thymine and between cytosine and guanine, but has a backbone that is held together by amide rather than by phosphodiester bonds. Oligonucleotides bases on RNA are known to act as templates that catalyse the non-enzymatic synthesis of their complements from activated mononucleotides, we now show that RNA oligonucleotides facilitate the synthesis of complementary PNA strands and vice versa. This suggests that a transition between different genetic systems can occur without loss of information.

Using Electrolyte Free Water Balance to Rationalize and Treat Dysnatremias

PubMed Central

Shah, Sanjeev R.; Bhave, Gautam

2018-01-01

Dysnatremias or abnormalities in plasma [Na+] are often termed disorders of water balance, an unclear physiologic concept often confused with changes in total fluid balance. However, most clinicians clearly recognize that hypertonic or hypotonic gains or losses alter plasma [Na+], while isotonic changes do not modify plasma [Na+]. This concept can be conceptualized as the electrolyte free water balance (EFWB), which defines the non-isotonic components of inputs and outputs to determine their effect on plasma [Na+]. EFWB is mathematically proportional to the rate of change in plasma [Na+] (dPNa/dt) and, therefore, is actively regulated to zero so that plasma [Na+] remains stable at its homeostatic set point. Dysnatremias are, therefore, disorders of EFWB and the relationship between EFWB and dPNa/dt provides a rationale for therapeutic strategies incorporating mass and volume balance. Herein, we leverage dPNa/dt as a desired rate of correction of plasma [Na+] to define a stepwise approach for the treatment of dysnatremias. PMID:29740578

[Abortion in Brazil: a household survey using the ballot box technique].

PubMed

Diniz, Debora; Medeiros, Marcelo

2010-06-01

This study presents the first results of the National Abortion Survey (PNA, Pesquisa Nacional de Aborto), a household random sample survey fielded in 2010 covering urban women in Brazil aged 18 to 39 years. The PNA combined two techniques, interviewer-administered questionnaires and self-administered ballot box questionnaires. The results of PNA show that at the end of their reproductive health one in five women has performed an abortion, with abortions being more frequent in the main reproductive ages, that is, from 18 to 29 years old. No relevant differentiation was observed in the practice of abortion among religious groups, but abortion was found to be more common among people with lower education. The use of medical drugs to induce abortion occurred in half of the abortions, and post-abortion hospitalization was observed among approximately half of the women who aborted. Such results lead to conclude that abortion is a priority in the Brazilian public health agenda.

Impact of In situ Postnitridation Annealing for Successful Fabrication of HfSiON Thin Film

NASA Astrophysics Data System (ADS)

Horii, Sadayoshi; Ishikawa, Dai; Sano, Atsushi; Imai, Yoshinori; Kunii, Yasuo

2007-05-01

For the successful integration of high-k gate dielectrics into advanced complementary metal-oxide-semiconductor (CMOS) processes, it is important to determine the stability of high-k materials during exposure to an ambient atmosphere. In this work, we investigated the effect of exposure to air on the nitrogen concentration in HfSiON films formed by sequentially combining HfSiO chemical vapor deposition (CVD), plasma nitridation, and postnitridation annealing (PNA). We observed that exposure to air after the nitridation step reduces the nitrogen concentration due to a reaction between the HfSiON surface and the constituents of atmospheric air. We also found that exposure to air for even a short time between nitridation and PNA leads to a significant loss of nitrogen concentration, indicating that in situ PNA is critical for achieving precise control of the nitridation. These results confirmed the importance of using clustered multichamber platforms for successful high-k fabrication.

Use of PNA FISH for blood cultures growing Gram-positive cocci in chains without a concomitant antibiotic stewardship intervention does not improve time to appropriate antibiotic therapy.

PubMed

Cosgrove, Sara E; Li, David X; Tamma, Pranita D; Avdic, Edina; Hadhazy, Eric; Wakefield, Teresa; Gherna, Michael; Carroll, Karen C

2016-09-01

Peptide nucleic acid fluorescence in situ hybridization (PNA FISH) is a rapid diagnostic assay that can identify certain organisms growing in blood cultures 30-90 min from the time of positive Gram-stain. Existing studies have demonstrated a clinical utility with this assay when antibiotic stewardship programs assist clinicians with interpreting the results. However, the benefit of these rapid assays in the absence of concomitant antibiotic stewardship involvement is unclear. In this randomized study of 220 patients with enterococcal or streptococcal bacteremia, we found that PNA FISH, in the absence of concomitant input from an antibiotic stewardship program, had no impact on time to effective or optimal therapy, length of hospital stay, or in-hospital mortality. Our results suggest that in the absence of guidance from an antibiotic stewardship program, the clinical benefits of rapid diagnostic microbiological tools may be reduced. Copyright © 2016 Elsevier Inc. All rights reserved.

Asymmetry of the winter extra-tropical teleconnections in the Northern Hemisphere associated with two types of ENSO

NASA Astrophysics Data System (ADS)

Feng, Juan; Chen, Wen; Li, Yanjie

2017-04-01

Asymmetric atmospheric responses to ENSO are revisited after dividing it into two types: eastern-Pacific (EP) and central-Pacific (CP) ENSO. The EP ENSO triggers two obvious asymmetric atmospheric teleconnections: One is the Pacific-North American-like teleconnection. Its asymmetry is characterized by weaker amplitudes during the EP La Niña than EP El Niño, which is caused by a much weaker EP La Niña tropical forcing and the resultant weaker extra-tropical vorticity forcing. The other is the Atlantic-Eurasian teleconnection with negative height anomalies in the subtropical Atlantic and Eurasia and positive anomalies in the high-latitude Atlantic and northeast Asia, which appears during the EP La Niña but not during the EP El Niño. The background state plays a vital role in this asymmetry. The EP La Niña-type basic state is more conducive to propagation of the wave rays into the Atlantic-Eurasian region compared to EP El Niño situation. In contrast, the CP ENSO yields an Arctic Oscillation-like teleconnection, presenting an appreciable asymmetry in the subtropical amplitudes that are stronger during the CP El Niño than during the CP La Niña. In this case, the distinct effects of the different background state on the equatorward wave rays are responsible for this asymmetry. Under the CP El Niño-type background state, the equatorward wave rays tend to be reflected at the latitudes where the zonal wind equals zero (U = 0), and then successfully captured by the subtropical westerly jet. However, under the CP La Niña-type background state, the equatorward wave rays disappear at U = 0 latitudes.

Inter-decadal modulation of ENSO teleconnections to the Indian Ocean in a coupled model: Special emphasis on decay phase of El Niño

NASA Astrophysics Data System (ADS)

Chowdary, J. S.; Parekh, Anant; Gnanaseelan, C.; Sreenivas, P.

2014-01-01

Inter-decadal modulation of El Niño-Southern Oscillation (ENSO) teleconnections to tropical Indian Ocean (TIO) is investigated in the coupled general circulation model Climate Forecast System (CFS) using a hundred year integration. The model is able to capture the periodicity of El Niño variability, which is similar to that of the observations. The maximum TIO/north Indian Ocean (NIO) SST warming (during spring following the decay phase of El Niño) associated with El Niño is well captured by the model. Detailed analysis reveals that the surface heat flux variations mainly contribute to the El Niño forced TIO SST variations both in observations and model. However, spring warming is nearly stationary throughout the model integration period, indicating poor inter-decadal El Niño teleconnections. The observations on the other hand displayed maximum SST warming with strong seasonality from epoch to epoch. The model El Niño decay delayed by more than two seasons, results in persistent TIO/NIO SST warming through the following December unlike in the observations. The ocean wave adjustments and persistent westerly wind anomalies over the equatorial Pacific are responsible for late decay of El Niño in the model. Consistent late decay of El Niño, throughout the model integration period (low variance), is mainly responsible for the poor inter-decadal ENSO teleconnections to TIO/NIO. This study deciphers that the model needs to produce El Niño decay phase variability correctly to obtain decadal-modulations in ENSO teleconnection.

Sensitivity of ENSO teleconnections to a warming background state.

NASA Astrophysics Data System (ADS)

Drouard, Marie; Cassou, Christophe

2016-04-01

The sensitivity of ENSO teleconnections to the background state is investigated using two ensembles of coupled model experiments, one representative of the pre-industrial climate and the other one expected of the end of the 21st century based on the high emission RCP85 scenario. A 30-year period of representative ENSO events bearing resemblance to observed ones is a priori selected from a 850-year pre-industrial simulation of the CNRM-CM5 model. Following the so-called pacemaker protocol, new coupled experiments are carried with the model SST being restored in the eastern tropical Pacific towards the selected anomalies, the rest of the globe being fully coupled. In the first set of experiments, the anomalous restoring is applied on top of pre-industrial mean ocean state and in the second, on top of RCP85 mean state. Two sets of 10-member of 30-year long integrations are then generated. By construction, they share the exact same ENSO and thus make it possible to strictly isolate the dependence of the ENSO teleconnections to a warmer background state. Results confirm the eastward shift of the ENSO-induced deepening Aleutian low as documented in the literature for the winter season. They also show changes in the wintertime teleconnection over the North Atlantic. Several diagnostic tools (such as E-vectors) are used to investigate the dynamics of the teleconnection between the tropical Pacific, the North Pacific and dowstream towards the North Atlantic along the jet wave guide. A more indirect route based on the change in the Walker cell and associated signals in the tropical Atlantic leading to the excitation of forced Rossby wave is also analysed.

Study of nucleic acid-gold nanorod interactions and detecting nucleic acid hybridization using gold nanorod solutions in the presence of sodium citrate.

PubMed

Kanjanawarut, Roejarek; Su, Xiaodi

2010-09-01

In this study, the authors report that sodium citrate can aggregate hexadecyl-trimethyl-ammonium ion(+)-coated gold nanorods (AuNRs), and nucleic acids of different charge and structure properties, i.e., single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), single-stranded peptide nucleic acid (PNA), and PNA-DNA complex, can bind to the AuNRs and therefore retard the sodium citrate-induced aggregation to different extents. The discovery that hybridized dsDNA (and the PNA-DNA complex) has a more pronounced protection effect than ssDNA (and PNA) allows the authors to develop a homogeneous phase AuNRs-based UV-visible (UV-vis) spectral assay for detecting specific sequences of oligonucleotides (20 mer) with a single-base-mismatch selectivity and a limit of detection of 5 nM. This assay involves no tedious bioconjugation and on-particle hybridization. The simple "set and test" format allows for a highly efficient hybridization in a homogeneous phase and a rapid display of the results in less than a minute. By measuring the degree of reduction in AuNR aggregation in the presence of different nucleic acid samples, one can assess how different nucleic acids interact with the AuNRs to complement the knowledge of spherical gold nanoparticles. Besides UV-vis characterization, transmission electron microscopy and zeta potential measurements were conduced to provide visual evidence of the particle aggregation and to support the discussion of the assay principle.

Water-Soluble Conjugated Polymers: Self-Assembly and Biosensor Applications

NASA Astrophysics Data System (ADS)

Bazan, Guillermo

2005-03-01

Homogeneous assays can be designed which take advantage of the optical amplification of conjugated polymers and the self-assembly characteristic of aqueous polyelectrolytes. For example, a ssDNA sequence sensor comprises an aqueous solution containing a cationic water soluble conjugated polymer such as poly(9,9-bis(trimethylammonium)-hexyl)-fluorene phenylene) with a peptide nucleic acid (PNA) labeled with a dye (PNA-C*). Signal transduction is controlled by hybridization of the neutral PNA-C* probe and the negative ssDNA target, resulting in favorable electrostatic interactions between the hybrid complex and the cationic polymer. Distance requirements for Förster energy transfer are thus met only when ssDNA of complementary sequence to the PNA-C* probe is present. Signal amplification by the conjugated polymer provides fluorescein emission >25 times higher than that of the directly excited dye. Transduction by electrostatic interactions followed by energy transfer is a general strategy. Examples involving other biomolecular recognition events, such as DNA/DNA, RNA/protein and RNA/RNA, will also be provided. The mechanism of biosensing will be discussed, with special attention to the varying contributions of hydrophobic and electrostatic forces, polymer conformation, charge density, local concentration of C*s and tailored defect sites for aggregation-induced optical changes. Finally, the water solubility of these conjugated polymers opens possibilities for spin casting onto organic materials, without dissolving the underlying layers. This property is useful for fabricating multilayer organic optoelectronic devices by simple solution techniques.

Tetrahedral DNA Nanoparticle Vector for Intracellular Delivery of Targeted Peptide Nucleic Acid Antisense Agents to Restore Antibiotic Sensitivity in Cefotaxime-Resistant Escherichia coli.

PubMed

Readman, John Benedict; Dickson, George; Coldham, Nick G

2017-06-01

The bacterial cell wall presents a barrier to the uptake of unmodified synthetic antisense oligonucleotides, such as peptide nucleic acids, and so is one of the greatest obstacles to the development of their use as therapeutic anti-bacterial agents. Cell-penetrating peptides have been covalently attached to antisense agents, to facilitate penetration of the bacterial cell wall and deliver their cargo into the cytoplasm. Although they are an effective vector for antisense oligonucleotides, they are not specific for bacterial cells and can exhibit growth inhibitory properties at higher doses. Using a bacterial cell growth assay in the presence of cefotaxime (CTX 16 mg/L), we have developed and evaluated a self-assembling non-toxic DNA tetrahedron nanoparticle vector incorporating a targeted anti-bla CTX-M-group 1 antisense peptide nucleic acid (PNA4) in its structure for penetration of the bacterial cell wall. A dose-dependent CTX potentiating effect was observed when PNA4 (0-40 μM) was incorporated into the structure of a DNA tetrahedron vector. The minimum inhibitory concentration (to CTX) of an Escherichia coli field isolate harboring a plasmid carrying bla CTX-M-3 was reduced from 35 to 16 mg/L in the presence of PNA4 carried by the DNA tetrahedron vector (40 μM), contrasting with no reduction in MIC in the presence of PNA4 alone. No growth inhibitory effects of the DNA tetrahedron vector alone were observed.

Accelerated Photobleaching of a Cyanine Dye in the Presence of a Ternary Target DNA, PNA Probe, Dye Catalytic Complex: A Molecular Diagnostic

PubMed Central

Wang, M.; Holmes-Davis, R.; Rafinski, Z.; Jedrzejewska, B.; Choi, K. Y.; Zwick, M.; Bupp, C.; Izmailov, A.; Paczkowski, J.; Warner, B.; Koshinsky, H.

2009-01-01

In many settings, molecular testing is needed but unavailable due to complexity and cost. Simple, rapid, and specific DNA detection technologies would provide important alternatives to existing detection methods. Here we report a novel, rapid nucleic acid detection method based on the accelerated photobleaching of the light-sensitive cyanine dye, 3,3′-diethylthiacarbocyanine iodide (DiSC2(3) I−), in the presence of a target genomic DNA and a complementary peptide nucleic acid (PNA) probe. On the basis of the UV–vis, circular dichroism, and fluorescence spectra of DiSC2(3) with PNA–DNA oligomer duplexes and on characterization of a product of photolysis of DiSC2(3) I−, a possible reaction mechanism is proposed. We propose that (1) a novel complex forms between dye, PNA, and DNA, (2) this complex functions as a photosensitizer producing 1O2, and (3) the 1O2 produced promotes photobleaching of dye molecules in the mixture. Similar cyanine dyes (DiSC3(3), DiSC4(3), DiSC5(3), and DiSCpy(3)) interact with preformed PNA–DNA oligomer duplexes but do not demonstrate an equivalent accelerated photobleaching effect in the presence of PNA and target genomic DNA. The feasibility of developing molecular diagnostic assays based on the accelerated photobleaching (the smartDNA assay) that results from the novel complex formed between DiSC2(3) and PNA–DNA is under way. PMID:19231844

A High-Resolution Speleothem Record From Florida of Atmospheric Teleconnections Since 1,500 Years Ago

NASA Astrophysics Data System (ADS)

Polk, J. S.; van Beynen, P.; Asmerom, Y.

2008-12-01

Understanding atmospheric teleconnections between tropical, subtropical, and higher-latitude regions of the North Atlantic Ocean is necessary to better evaluate the anthropogenic contribution to climate change. Here, we present a precisely dated, high- resolution speleothem record of stable isotopes and trace elements from Florida spanning the last 1,500 years. By using a multi-proxy approach, the different climatic influences were deconvolved, including the NAO, ENSO, PDO, and ITCZ, which all can affect our region. Further comparison using time-series analysis between our data and other high-resolution records covering this same period reveal differing influences of these teleconnections on geographic regions. Our record shows both the influence of changing rainfall above the cave and the influence of sea surface temperatures on atmospheric convection caused by atmospheric-oceanic variability over time.

Future Changes to ENSO Temperature and Precipitation Teleconnections Under Warming

NASA Astrophysics Data System (ADS)

Perry, S.; McGregor, S.; Sen Gupta, A.; England, M. H.

2016-12-01

As the dominant mode of interannual climate variability, the El Niño-Southern Oscillation (ENSO) modulates temperature and rainfall globally, additionally contributing to weather extremes. Anthropogenic climate change has the potential to alter the strength and frequency of ENSO and may also alter ENSO-driven atmospheric teleconnections, affecting ecosystems and human activity in regions far removed from the tropical Pacific. State-of-art climate models exhibit considerable disagreement in projections of future changes in ENSO sea surface temperature variability. Despite this uncertainty, recent model studies suggest that the precipitation response to ENSO will be enhanced in the tropical Pacific under future warming, and as such the societal impacts of ENSO will increase. Here we use temperature and precipitation data from an ensemble of 41 CMIP5 models to show where ENSO teleconnections are being enhanced and dampened in a high-emission future scenario (RCP8.5) focusing on the changes that are occurring over land areas globally. Although there is some spread between the model projections, robust changes with strong ensemble agreement are found in certain locations, including amplification of teleconnections in southeast Australia, South America and the Maritime Continent. Our results suggest that in these regions future ENSO events will lead to more extreme temperature and rainfall responses.

Applying complex networks to evaluate precipitation patterns over South America

NASA Astrophysics Data System (ADS)

Ciemer, Catrin; Boers, Niklas; Barbosa, Henrique; Kurths, Jürgen; Rammig, Anja

2016-04-01

The climate of South America exhibits pronounced differences between the wet- and the dry-season, which are accompanied by specific synoptic events like changes in the location of the South American Low Level Jet (SALLJ) and the establishment of the South American Convergence Zone (SACZ). The onset of these events can be related to the presence of typical large-scale precipitation patterns over South America, as previous studies have shown[1,2]. The application of complex network methods to precipitation data recently received increased scientific attention for the special case of extreme events, as it is possible with such methods to analyze the spatiotemporal correlation structure as well as possible teleconnections of these events[3,4]. In these approaches the correlation between precipitation datasets is calculated by means of Event Synchronization which restricts their applicability to extreme precipitation events. In this work, we propose a method which is able to consider not only extreme precipitation but complete time series. A direct application of standard similarity measures in order to correlate precipitation time series is impossible due to their intricate statistical properties as the large amount of zeros. Therefore, we introduced and evaluated a suitable modification of Pearson's correlation coefficient to construct spatial correlation networks of precipitation. By analyzing the characteristics of spatial correlation networks constructed on the basis of this new measure, we are able to determine coherent areas of similar precipitation patterns, spot teleconnections of correlated areas, and detect central regions for precipitation correlation. By analyzing the change of the network over the year[5], we are also able to determine local and global changes in precipitation correlation patterns. Additionally, global network characteristics as the network connectivity yield indications for beginning and end of wet- and dry season. In order to identify large-scale synoptic events like the SACZ and SALLJ onset, detecting the changes of correlation over time between certain regions is of significant relevance. [1] Nieto-Ferreira et al. Quarterly Journal of the Royal Meteorological Society (2011) [2] Vera et al. Bulletin of the American Meteorological Society (2006) [3] Quiroga et al. Physical review E (2002) [4] Boers et al. nature communications (2014) [5] Radebach et al. Physical review E (2013)

Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns.

PubMed

Iglesias, Isabel; Lorenzo, M Nieves; Lázaro, Clara; Fernandes, M Joana; Bastos, Luísa

2017-12-31

Sea level anomaly (SLA), provided globally by satellite altimetry, is considered a valuable proxy for detecting long-term changes of the global ocean, as well as short-term and annual variations. In this manuscript, monthly sea level anomaly grids for the period 1993-2013 are used to characterise the North Atlantic Ocean variability at inter-annual timescales and its response to the North Atlantic main patterns of atmospheric circulation variability (North Atlantic Oscillation, Eastern Atlantic, Eastern Atlantic/Western Russia, Scandinavian and Polar/Eurasia) and main driven factors as sea level pressure, sea surface temperature and wind fields. SLA variability and long-term trends are analysed for the North Atlantic Ocean and several sub-regions (North, Baltic and Mediterranean and Black seas, Bay of Biscay extended to the west coast of the Iberian Peninsula, and the northern North Atlantic Ocean), depicting the SLA fluctuations at basin and sub-basin scales, aiming at representing the regions of maximum sea level variability. A significant correlation between SLA and the different phases of the teleconnection patterns due to the generated winds, sea level pressure and sea surface temperature anomalies, with a strong variability on temporal and spatial scales, has been identified. Long-term analysis reveals the existence of non-stationary inter-annual SLA fluctuations in terms of the temporal scale. Spectral density analysis has shown the existence of long-period signals in the SLA inter-annual component, with periods of ~10, 5, 4 and 2years, depending on the analysed sub-region. Also, a non-uniform increase in sea level since 1993 is identified for all sub-regions, with trend values between 2.05mm/year, for the Bay of Biscay region, and 3.98mm/year for the Baltic Sea (no GIA correction considered). The obtained results demonstrated a strong link between the atmospheric patterns and SLA, as well as strong long-period fluctuations of this variable in spatial and temporal scales. Copyright © 2017 Elsevier B.V. All rights reserved.

Upper air teleconnections to Ob River flows and tree rings

NASA Astrophysics Data System (ADS)

Meko, David; Panyushkina, Irina; Agafonov, Leonid

2015-04-01

The Ob River, one of the world's greatest rivers, with a catchment basin about the size of Western Europe, contributes 12% or more of the annual freshwater inflow to the Arctic Ocean. The input of heat and fresh water is important to the global climate system through effects on sea ice, salinity, and the thermohaline circulation of the ocean. As part of a tree-ring project to obtain multi-century long information on variability of Ob River flows, a network of 18 sites of Pinus, Larix, Populus and Salix has been collected along the Ob in the summers of 2013 and 2014. Analysis of collections processed so far indicates a significant relationship of tree-growth to river discharge. Moderation of the floodplain air temperature regime by flooding appears to be an important driver of the tree-ring response. In unraveling the relationship of tree-growth to river flows, it is important to identify atmospheric circulation features directly linked to observed time series variations of flow and tree growth. In this study we examine statistical links between primary teleconnection modes of Northern Hemisphere upper-air (500 mb) circulation, Ob River flow, and tree-ring chronologies. Annual discharge at the mouth of the Ob River is found to be significantly positively related to the phase of the East Atlantic (EA) pattern, the second prominent mode of low-frequency variability over the North Atlantic. The EA pattern, consisting of a north-south dipole of pressure-anomaly centers spanning the North Atlantic from east to west, is associated with a low-pressure anomaly centered over the Ob River Basin, and with a pattern of positive precipitation anomaly of the same region. The positive correlation of discharge and EA is consistent with these know patterns, and is contrasted with generally negative (though smaller) correlations between EA and tree-ring chronologies. The signs of correlations are consistent with a conceptual model of river influence on tree growth through air temperature. Future work aims at combining the tree-ring samples from living trees and remnant wood to reconstruction to quantitiative reconstruction of annual flow over the past millennium.

Origin of seasonal predictability for summer climate over the Northwestern Pacific

PubMed Central

Kosaka, Yu; Xie, Shang-Ping; Lau, Ngar-Cheung; Vecchi, Gabriel A.

2013-01-01

Summer climate in the Northwestern Pacific (NWP) displays large year-to-year variability, affecting densely populated Southeast and East Asia by impacting precipitation, temperature, and tropical cyclones. The Pacific–Japan (PJ) teleconnection pattern provides a crucial link of high predictability from the tropics to East Asia. Using coupled climate model experiments, we show that the PJ pattern is the atmospheric manifestation of an air–sea coupled mode spanning the Indo-NWP warm pool. The PJ pattern forces the Indian Ocean (IO) via a westward propagating atmospheric Rossby wave. In response, IO sea surface temperature feeds back and reinforces the PJ pattern via a tropospheric Kelvin wave. Ocean coupling increases both the amplitude and temporal persistence of the PJ pattern. Cross-correlation of ocean–atmospheric anomalies confirms the coupled nature of this PJIO mode. The ocean–atmosphere feedback explains why the last echoes of El Niño–Southern Oscillation are found in the IO-NWP in the form of the PJIO mode. We demonstrate that the PJIO mode is indeed highly predictable; a characteristic that can enable benefits to society. PMID:23610388

The East Atlantic - West Russia Teleconnection in the North Atlantic: Climate Impact and Relation to Rossby Wave Propagation

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon

2014-01-01

Large-scale winter teleconnection of the East Atlantic - West Russia (EA-WR) over the Atlantic and surrounding regions is examined in order to quantify its impacts on temperature and precipitation and identify the physical mechanisms responsible for its existence. A rotated empirical orthogonal function (REOF) analysis of the upper-tropospheric monthly height field captures successfully the EA-WR pattern and its interannual variation, with the North Atlantic Oscillation as the first mode. EA-WRs climate impact extends from eastern North America to Eurasia. The positive (negative) EA-WR produces positive (negative) temperature anomalies over the eastern US, western Europe and Russia east of Caspian Sea, with negative (positive) anomalies over eastern Canada, eastern Europe including Ural Mountains and the Middle East. These anomalies are largely explained by lower-tropospheric temperature advections. Positive (negative) precipitation anomalies are found over the mid-latitude Atlantic and central Russia around 60E, where lower-level cyclonic (anticyclonic) circulation anomaly is dominant. The eastern Canada and the western Europe are characterized by negative (positive) precipitation anomalies.The EA-WR is found to be closely associated with Rossby wave propagation. Wave activity fluxes show that it is strongly tied to large-scale stationary waves. Furthermore, a stationary wave model (SWM) forced with vorticity transients in the mid-latitude Atlantic (approximately 40N) or diabatic heat source over the subtropical Atlantic near the Caribbean Sea produces well-organized EA-WR-like wave patterns, respectively. Sensitivity tests with the SWM indicate improvement in the simulation of the EA-WR when the mean state is modified to have a positive NAO component that enhances upper-level westerlies between 40-60N.

Interannual and low-frequency variability of Upper Indus Basin winter/spring precipitation in observations and CMIP5 models

NASA Astrophysics Data System (ADS)

Greene, Arthur M.; Robertson, Andrew W.

2017-12-01

An assessment is made of the ability of general circulation models in the CMIP5 ensemble to reproduce observed modes of low-frequency winter/spring precipitation variability in the region of the Upper Indus basin (UIB) in south-central Asia. This season accounts for about two thirds of annual precipitation totals in the UIB and is characterized by "western disturbances" propagating along the eastward extension of the Mediterranean storm track. Observational data are utilized for for spatiotemporal characterization of the precipitation seasonal cycle, to compute seasonalized spectra and finally, to examine teleconnections, in terms of large-scale patterns in sea-surface temperature (SST) and atmospheric circulation. Annual and lowpassed variations are found to be associated primarily with SST modes in the tropical and extratropical Pacific. A more obscure link to North Atlantic SST, possibly related to the North Atlantic Oscillation, is also noted. An ensemble of 31 CMIP5 models is then similarly assessed, using unforced preindustrial multi-century control runs. Of these models, eight are found to reproduce well the two leading modes of the observed seasonal cycle. This model subset is then assessed in the spectral domain and with respect to teleconnection patterns, where a range of behaviors is noted. Two model families each account for three members of this subset. The degree of within-family similarity in behavior is shown to reflect underlying model differences. The results provide estimates of unforced regional hydroclimate variability over the UIB on interannual and decadal scales and the corresponding far-field influences, and are of potential relevance for the estimation of uncertainties in future water availability.

Regionalizing Africa: Patterns of Precipitation Variability in Observations and Global Climate Models

NASA Technical Reports Server (NTRS)

Badr, Hamada S.; Dezfuli, Amin K.; Zaitchik, Benjamin F.; Peters-Lidard, Christa D.

2016-01-01

Many studies have documented dramatic climatic and environmental changes that have affected Africa over different time scales. These studies often raise questions regarding the spatial extent and regional connectivity of changes inferred from observations and proxies and/or derived from climate models. Objective regionalization offers a tool for addressing these questions. To demonstrate this potential, applications of hierarchical climate regionalizations of Africa using observations and GCM historical simulations and future projections are presented. First, Africa is regionalized based on interannual precipitation variability using Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) data for the period 19812014. A number of data processing techniques and clustering algorithms are tested to ensure a robust definition of climate regions. These regionalization results highlight the seasonal and even month-to-month specificity of regional climate associations across the continent, emphasizing the need to consider time of year as well as research question when defining a coherent region for climate analysis. CHIRPS regions are then compared to those of five GCMs for the historic period, with a focus on boreal summer. Results show that some GCMs capture the climatic coherence of the Sahel and associated teleconnections in a manner that is similar to observations, while other models break the Sahel into uncorrelated subregions or produce a Sahel-like region of variability that is spatially displaced from observations. Finally, shifts in climate regions under projected twenty-first-century climate change for different GCMs and emissions pathways are examined. A projected change is found in the coherence of the Sahel, in which the western and eastern Sahel become distinct regions with different teleconnections. This pattern is most pronounced in high-emissions scenarios.

Ordered Self-Assembled Monolayers of Peptide Nucleic Acids with DNA Recognition Capability

NASA Astrophysics Data System (ADS)

Briones, C.; Mateo-Marti, E.; Gómez-Navarro, C.; Parro, V.; Román, E.; Martín-Gago, J. A.

2004-11-01

We report on the formation of ordered self-assembled monolayers (SAMs) of single-stranded peptide nucleic acids (ssPNA). In spite of their remarkable length (7nm) thiolated PNAs assemble standing up on gold surfaces similarly to the SAMs of short alkanethiols. SAMs of ssPNA recognize complementary nucleic acids, acting as specific biosensors that discriminate even a point mutation in target ssDNA. These results are obtained by surface characterization techniques that avoid labeling of the target molecule: x-ray photoemission, x-ray absorption and atomic force microscopy.

Disruptions of El Niño–Southern Oscillation teleconnections by the Madden–Julian Oscillation

USGS Publications Warehouse

Hoell, Andrew; Barlow, Mathew; Wheeler, Mathew; Funk, Christopher C.

2014-01-01

The El Niño–Southern Oscillation (ENSO) is the leading mode of interannual variability, with global impacts on weather and climate that have seasonal predictability. Research on the link between interannual ENSO variability and the leading mode of intraseasonal variability, the Madden–Julian oscillation (MJO), has focused mainly on the role of MJO initiating or terminating ENSO. We use observational analysis and modeling to show that the MJO has an important simultaneous link to ENSO: strong MJO activity significantly weakens the atmospheric branch of ENSO. For weak MJO conditions relative to strong MJO conditions, the average magnitude of ENSO-associated tropical precipitation anomalies increases by 63%, and the strength of hemispheric teleconnections increases by 58%. Since the MJO has predictability beyond three weeks, the relationships shown here suggest that there may be subseasonal predictability of the ENSO teleconnections to continental circulation and precipitation.

Urban land teleconnections and sustainability

PubMed Central

Seto, Karen C.; Reenberg, Anette; Boone, Christopher G.; Fragkias, Michail; Haase, Dagmar; Langanke, Tobias; Marcotullio, Peter; Munroe, Darla K.; Olah, Branislav; Simon, David

2012-01-01

This paper introduces urban land teleconnections as a conceptual framework that explicitly links land changes to underlying urbanization dynamics. We illustrate how three key themes that are currently addressed separately in the urban sustainability and land change literatures can lead to incorrect conclusions and misleading results when they are not examined jointly: the traditional system of land classification that is based on discrete categories and reinforces the false idea of a rural–urban dichotomy; the spatial quantification of land change that is based on place-based relationships, ignoring the connections between distant places, especially between urban functions and rural land uses; and the implicit assumptions about path dependency and sequential land changes that underlie current conceptualizations of land transitions. We then examine several environmental “grand challenges” and discuss how urban land teleconnections could help research communities frame scientific inquiries. Finally, we point to existing analytical approaches that can be used to advance development and application of the concept. PMID:22550174

El Nino-like Teleconnection Increases California Precipitation in Response to Warming

NASA Astrophysics Data System (ADS)

Allen, R.

2017-12-01

Future California (CA) precipitation projections, including those from the most recent Climate Model Intercomparison Project (CMIP5), remain uncertain. This uncertainty is related to several factors, including relatively large internal climate variability, model shortcomings, and because CA lies within a transition zone, where mid-latitude regions are expected to become wetter and subtropical regions drier. Here, we use a multitude of models to show CA may receive more precipitation in the future under a business-as-usual scenario. The boreal winter season-when most of the CA precipitation increase occurs-is associated with robust changes in the mean circulation reminiscent of an El Nino teleconnection. Using idealized simulations with two different models, we further show that warming of tropical Pacific sea surface temperatures accounts for these changes. Models that better simulate the observed El Nino-CA precipitation teleconnection yield larger, and more consistent increases in CA precipitation through the twenty-first century.

Climate, fishery and society interactions: Observations from the North Atlantic

NASA Astrophysics Data System (ADS)

Hamilton, Lawrence C.

2007-11-01

Interdisciplinary studies comparing fisheries-dependent regions across the North Atlantic find a number of broad patterns. Large ecological shifts, disastrous to historical fisheries, have resulted when unfavorable climatic events occur atop overfishing. The "teleconnections" linking fisheries crises across long distances include human technology and markets, as well as climate or migratory fish species. Overfishing and climate-driven changes have led to a shift downwards in trophic levels of fisheries takes in some ecosystems, from dominance by bony fish to crustaceans. Fishing societies adapt to new ecological conditions through social reorganization that have benefited some people and places, while leaving others behind. Characteristic patterns of demographic change are among the symptoms of such reorganization. These general observations emerge from a review of recent case studies of individual fishing communities, such as those conducted for the North Atlantic Arc research project.

Interphotoreceptor matrix components in retinal cell transplants.

PubMed

Juliusson, B; Mieziewska, K; Bergström, A; Wilke, K; Van Veen, T; Ehinger, B

1994-05-01

To further investigate the functional potential of retinal transplants we have used immunocytochemistry to study the distribution of four different interphotoreceptor matrix (IPM)-specific components in rabbit retinal transplants. The different components were: interphotoreceptor retinoid-binding protein (IRBP), chondroitin-6-sulfate, F22 antigen and peanut agglutinin (PNA) binding structures. IRBP acts as a retinoid-transport protein between the neural retina and the retinal pigment epithelium. Chondroitin-6-sulfate is a glycosaminoglycan and a part of the insoluble IPM skeleton. The identity and role of the F22 antigen is not known. However, it is a 250 kDa protein localized to specific extracellular compartments such as teh IPM. PNA is a lectin with a high binding affinity for D-galactose-beta (1-3) N-acetyl-D-galactosamine disaccharide linkages and binds to IPM domains surrounding cones, but not rods. The transplants (15-day-old embryonic rabbit retina) were placed between the neural retina and retinal pigment epithelium in adult hosts. The transplants developed the typical rosette formations with photoreceptors toward the center. IRBP labeling was distinct in the IPM in the host retina. However, no IRBP labeling could be detected in the transplants. The chondroitin-6-sulfate and F22 antibodies strongly labeled the IPM in the host retina and corresponding structures in the center of rosettes. A cone-specific labeling with PNA could be seen in the host retina. In the transplants, however, PNA labeling appeared in association with many more photoreceptors than in the host retina. There is no previous study available on the IPM in retinal cell transplants.(ABSTRACT TRUNCATED AT 250 WORDS)

Composite Quality Measures for Common Inpatient Medical Conditions

PubMed Central

Chen, Lena M.; Staiger, Douglas O.; Birkmeyer, John D.; Ryan, Andrew M.; Zhang, Wenying; Dimick, Justin B.

2014-01-01

Background Public reporting on quality aims to help patients select better hospitals. However, individual quality measures are sub-optimal in identifying superior and inferior hospitals based on outcome performance. Objective To combine structure, process, and outcome measures into an empirically-derived composite quality measure for heart failure (HF), acute myocardial infarction (AMI), and pneumonia (PNA). To assess how well the composite measure predicts future high and low performers, and explains variance in future hospital mortality. Research Design Using national Medicare data, we created a cohort of older patients treated at an acute care hospital for HF (n=1,203,595), AMI (n=625,595), or PNA (n=1,234,299). We ranked hospitals based on their July 2005 to June 2008 performance on the composite. We then estimated the odds of future (July to December 2009) 30-day, risk-adjusted mortality at the worst vs. best quintile of hospitals. We repeated this analysis using 2005-2008 performance on existing quality indicators, including mortality. Results The composite (vs. Hospital Compare) explained 68% (vs. 39%) of variation in future AMI mortality rates. In 2009, if an AMI patient had chosen a hospital in the worst vs. best quintile of performance using 2005-2008 composite (vs. Hospital Compare) rankings, he or she would have had 1.61 (vs. 1.39) times the odds of dying in 30 days (p-value for difference < 0.001). Results were similar for HF and PNA. Conclusions Composite measures of quality for HF, AMI, and PNA performed better than existing measures at explaining variation in future mortality and predicting future high and low performers. PMID:23942222

Evidence of Teleconnections between the Peruvian central Andes and Northeast Brazil during extreme rainfall events

NASA Astrophysics Data System (ADS)

Sulca, J. C.; Vuille, M. F.; Silva, F. Y.; Takahashi, K.

2013-12-01

Knowledge about changes in regional circulation and physical processes associated with extreme rainfall events in South America is limited. Here we investigate such events over the Mantaro basin (MB) located at (10°S-13°S; 73°W-76°W) in the central Peruvian Andes and Northeastern Brazil (NEB), located at (9°S-15°S; 39°W-46°W). Occasional dry and wet spells can be observed in both areas during the austral summer season. The main goal of this study is to investigate potential teleconnections between extreme rainfall events in MB and NEB during austral summer. We define wet (dry) spells as periods that last for at least 3 (5) consecutive days with rainfall above (below) the 70 (30) percentile. To identify the dates of ocurrence of these events, we used daily accumulated rainfall data from 14 climate stations located in the Mantaro basin for the period 1965 to 2002. In NEB we defined a rainfall index which is based on average daily gridded rainfall data within the region for the same period. Dry (wet spells) in the MB are associated with positive (negative) OLR anomalies which extend over much of the tropical Andes, indicating the large-scale nature of these events. At 200 hPa anomalous easterly (westerly) zonal winds aloft accompany wet (dry) spells. Composite anomalies of dry spells in MB reveal significant contemporaneous precipitation anomalies of the opposite sign over NEB, which suggest that intraseasonal precipitation variability over the two regions may be dynamically linked. Indeed upper-tropospheric circulation anomalies over the central Andes extend across South America and appear to be tied to an adjustment in the Bolivian High-Nordeste Low system. Dry (wet) spells in NEB are equally associated with a large-scale pattern of positive (negative) OLR anomalies; however, there are no related significant OLR anomalies over the MB during these events. Dry (wet) spells are associated with robust patterns of anomalous wind fields at both low and upper levels, caused by a changing position of the South Atlantic Convergence Zone (SACZ) toward the southwest (northeast). But, there is no coincident robust pattern of wind anomalies over the Mantaro Basin. In conclusion, dry spells in the Mantaro basin appear to be dynamically linked to wet spells in NEB, since 62% of all dry events in MB coincide with wet spells in NEB (35% of all events). The dynamical link explaining the observed teleconnection and the resulting dipole pattern between precipitation extremes in the MB and NEB region, respectively, appears to be related to intraseasonal variability in the Bolivian High - Nordeste Low system. Only 26.53% of all wet spells, however, coincide with dry spells in NEB (12.15% of all events). While circulation anomalies that affect precipitation extremes in the MB have the potential to also affect the precipitation characteristics in NEB, the opposite is not the case. Extreme events in NEB are primarily affected by NE-SW displacement in the SACZ, a mechanism that is of little relevance for precipitation extremes in the MB.

Synthesis and characterization of metastable, 20 nm-sized Pna21-LiCoPO4 nanospheres

NASA Astrophysics Data System (ADS)

Ludwig, Jennifer; Nordlund, Dennis; Doeff, Marca M.; Nilges, Tom

2017-04-01

The majority of research activities on LiCoPO4 are focused on the phospho-olivine (space group Pnma), which is a promising high-voltage cathode material for Li-ion batteries. In contrast, comparably little is known about its metastable Pna21 modification. Herein, we present a comprehensive study on the structure-property relationships of 15-20 nm Pna21-LiCoPO4 nanospheres prepared by a simple microwave-assisted solvothermal process. Unlike previous reports, the results indicate that the compound is non-stoichiometric and shows cation-mixing with Co ions on the Li sites, which provides an explanation for the poor electrochemical performance. Co L2,3-edge X-ray absorption spectroscopic data confirm the local tetrahedral symmetry of Co2+. Comprehensive studies on the thermal stability using thermogravimetric analysis, differential scanning calorimetry, and in situ powder X-ray diffraction show an exothermic phase transition to olivine Pnma-LiCoPO4 at 527 °C. The influence of the atmosphere and the particle size on the thermal stability is also investigated.

Rapid Identification of Staphylococcus aureus Directly from Blood Cultures by Fluorescence In Situ Hybridization with Peptide Nucleic Acid Probes

PubMed Central

Oliveira, Kenneth; Procop, Gary W.; Wilson, Deborah; Coull, James; Stender, Henrik

2002-01-01

A new fluorescence in situ hybridization (FISH) method with peptide nucleic acid (PNA) probes for identification of Staphylococcus aureus directly from positive blood culture bottles that contain gram-positive cocci in clusters (GPCC) is described. The test (the S. aureus PNA FISH assay) is based on a fluorescein-labeled PNA probe that targets a species-specific sequence of the 16S rRNA of S. aureus. Evaluations with 17 reference strains and 48 clinical isolates, including methicillin-resistant and methicillin-susceptible S. aureus species, coagulase-negative Staphylococcus species, and other clinically relevant and phylogenetically related bacteria and yeast species, showed that the assay had 100% sensitivity and 96% specificity. Clinical trials with 87 blood cultures positive for GPCC correctly identified 36 of 37 (97%) of the S. aureus-positive cultures identified by standard microbiological methods. The positive and negative predictive values were 100 and 98%, respectively. It is concluded that this rapid method (2.5 h) for identification of S. aureus directly from blood culture bottles that contain GPCC offers important information for optimal antibiotic therapy. PMID:11773123

Combined effects of recent Pacific cooling and Indian Ocean warming on the Asian monsoon.

PubMed

Ueda, Hiroaki; Kamae, Youichi; Hayasaki, Masamitsu; Kitoh, Akio; Watanabe, Shigeru; Miki, Yurisa; Kumai, Atsuki

2015-11-13

Recent research indicates that the cooling trend in the tropical Pacific Ocean over the past 15 years underlies the contemporaneous hiatus in global mean temperature increase. During the hiatus, the tropical Pacific Ocean displays a La Niña-like cooling pattern while sea surface temperature (SST) in the Indian Ocean has continued to increase. This SST pattern differs from the well-known La Niña-induced basin-wide cooling across the Indian Ocean on the interannual timescale. Here, based on model experiments, we show that the SST pattern during the hiatus explains pronounced regional anomalies of rainfall in the Asian monsoon region and thermodynamic effects due to specific humidity change are secondary. Specifically, Indo-Pacific SST anomalies cause convection to intensify over the tropical western Pacific, which in turn suppresses rainfall in mid-latitude East Asia through atmospheric teleconnection. Overall, the tropical Pacific SST effect opposes and is greater than the Indian Ocean SST effect.

Influence of climate variability on near-surface ozone depletion events in the Arctic spring

NASA Astrophysics Data System (ADS)

Koo, Ja-Ho; Wang, Yuhang; Jiang, Tianyu; Deng, Yi; Oltmans, Samuel J.; Solberg, Sverre

2014-04-01

Near-surface ozone depletion events (ODEs) generally occur in the Arctic spring, and the frequency shows large interannual variations. We use surface ozone measurements at Barrow, Alert, and Zeppelinfjellet to analyze if their variations are due to climate variability. In years with frequent ODEs at Barrow and Alert, the western Pacific (WP) teleconnection pattern is usually in its negative phase, during which the Pacific jet is strengthened but the storm track originated over the western Pacific is weakened. Both factors tend to reduce the transport of ozone-rich air mass from midlatitudes to the Arctic, creating a favorable environment for the ODEs. The correlation of ODE frequencies at Zeppelinfjellet with WP indices is higher in the 2000s, reflecting stronger influence of the WP pattern in recent decade to cover ODEs in broader Arctic regions. We find that the WP pattern can be used to diagnose ODE changes and subsequent environmental impacts in the Arctic spring.

Periodicity during hypercapnic and hypoxic stimulus is crucial in distinct aspects of phrenic nerve plasticity.

PubMed

Stipica, I; Pavlinac Dodig, I; Pecotic, R; Dogas, Z; Valic, Z; Valic, M

2016-01-01

This study was undertaken to determine pattern sensitivity of phrenic nerve plasticity in respect to different respiratory challenges. We compared long-term effects of intermittent and continuous hypercapnic and hypoxic stimuli, and combined intermittent hypercapnia and hypoxia on phrenic nerve plasticity. Adult, male, urethane-anesthetized, vagotomized, paralyzed, mechanically ventilated Sprague-Dawley rats were exposed to: acute intermittent hypercapnia (AIHc or AIHc(O2)), acute intermittent hypoxia (AIH), combined intermittent hypercapnia and hypoxia (AIHcH), continuous hypercapnia (CHc), or continuous hypoxia (CH). Peak phrenic nerve activity (pPNA) and burst frequency were analyzed during baseline (T0), hypercapnia or hypoxia exposures, at 15, 30, and 60 min (T60) after the end of the stimulus. Exposure to acute intermittent hypercapnia elicited decrease of phrenic nerve frequency from 44.25+/-4.06 at T0 to 35.29+/-5.21 at T60, (P=0.038, AIHc) and from 45.5+/-2.62 to 37.17+/-3.68 breaths/min (P=0.049, AIHc(O2)), i.e. frequency phrenic long term depression was induced. Exposure to AIH elicited increase of pPNA at T60 by 141.0+/-28.2 % compared to baseline (P=0.015), i.e. phrenic long-term facilitation was induced. Exposure to AIHcH, CHc, or CH protocols failed to induce long-term plasticity of the phrenic nerve. Thus, we conclude that intermittency of the hypercapnic or hypoxic stimuli is needed to evoke phrenic nerve plasticity.

An Investigation of the Thermal Decomposition of 1, 4-Butanediammonium Dinitrate and Selected Composites with Ammonium and Potassium Nitrates

DTIC Science & Technology

1989-02-01

Reference 20. (8) PN H dCHCHCHH 2T NO2 + H20 PNA (9) PNA - 2C H2CH 2 CH2 NNO + other products PNSA (10) BDD . 02 NNH(CH2 )4 NHNO 2 + 2H2 0 BONA (11) BDNA ...ONNH(CH2 )4 NHNO + other products BONSA 2H+ (12) BDNA --> ý4-CH2CH2 -N=N=0+] 2 + 2H2 0 (a) (13) (a) --- 4 [(CH2 )4 ]++ + 2N2 0 (b) (14) (b) --- H2 C

Efficacy of peptide nucleic acid and selected conjugates against specific cellular pathologies of amyotrophic lateral sclerosis.

PubMed

Browne, Elisse C; Parakh, Sonam; Duncan, Luke F; Langford, Steven J; Atkin, Julie D; Abbott, Belinda M

2016-04-01

Cellular studies have been undertaken on a nonamer peptide nucleic acid (PNA) sequence, which binds to mRNA encoding superoxide dismutase 1, and a series of peptide nucleic acids conjugated to synthetic lipophilic vitamin analogs including a recently prepared menadione (vitamin K) analog. Reduction of both mutant superoxide dismutase 1 inclusion formation and endoplasmic reticulum stress, two of the key cellular pathological hallmarks in amyotrophic lateral sclerosis, by two of the prepared PNA oligomers is reported for the first time. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Large fluctuations of dissolved oxygen in the Indian and Pacific oceans during Dansgaard-Oeschger oscillations caused by variations of North Atlantic Deep Water subduction

NASA Astrophysics Data System (ADS)

Schmittner, Andreas; Galbraith, Eric D.; Hostetler, Steven W.; Pedersen, Thomas F.; Zhang, Rong

2007-09-01

Paleoclimate records from glacial Indian and Pacific oceans sediments document millennial-scale fluctuations of subsurface dissolved oxygen levels and denitrification coherent with North Atlantic temperature oscillations. Yet the mechanism of this teleconnection between the remote ocean basins remains elusive. Here we present model simulations of the oxygen and nitrogen cycles that explain how changes in deepwater subduction in the North Atlantic can cause large and synchronous variations of oxygen minimum zones throughout the Northern Hemisphere of the Indian and Pacific oceans, consistent with the paleoclimate records. Cold periods in the North Atlantic are associated with reduced nutrient delivery to the upper Indo-Pacific oceans, thereby decreasing productivity. Reduced export production diminishes subsurface respiration of organic matter leading to higher oxygen concentrations and less denitrification. This effect of reduced oxygen consumption dominates at low latitudes. At high latitudes in the Southern Ocean and North Pacific, increased mixed layer depths and steepening of isopycnals improve ocean ventilation and oxygen supply to the subsurface. Atmospheric teleconnections through changes in wind-driven ocean circulation modify this basin-scale pattern regionally. These results suggest that changes in the Atlantic Ocean circulation, similar to those projected by climate models to possibly occur in the centuries to come because of anthropogenic climate warming, can have large effects on marine ecosystems and biogeochemical cycles even in remote areas.

The mechanism of growth of the low-frequency East Asia-Pacific teleconnection and the triggering role of tropical intraseasonal oscillation

NASA Astrophysics Data System (ADS)

Wang, Jiabao; Wen, Zhiping; Wu, Renguang; Guo, Yuanyuan; Chen, Zesheng

2016-06-01

The East Asia-Pacific (EAP) pattern is a well-known meridional teleconnection over East Asia during boreal summer. In this study, the mechanism for growth of the EAP on intraseasonal timescale is investigated through a vorticity budget. It is found that the beta-effect and high-frequency transient eddies have primary contributions to the growth of the low-frequency EAP. The former leads to a westward shift of disturbances associated with the low-frequency EAP and the latter favors an amplification of disturbances, respectively. The interaction between low-frequency disturbances and zonal flow has a damping effect by dragging disturbances eastward. The impact of boreal summer intraseasonal oscillation (BSISO) on the triggering of the low-frequency EAP is also examined in this study based on observational analysis and a linear model experiment. It is shown that an elongated anomalous convection band located in the vicinity of Philippines associated with the dominant mode of BSISO has a significant impact on the initiation of low-frequency EAP via Rossby wave propagation, whereas anomalous convection located over the North Indian Ocean has a limited impact. Based on the results of present study, the low-frequency EAP could be a self-sustained mode, and the BSISO plays a substantial role in triggering the low-frequency EAP.

Climate and wildfires in the North American boreal forest.

PubMed

Macias Fauria, Marc; Johnson, E A

2008-07-12

The area burned in the North American boreal forest is controlled by the frequency of mid-tropospheric blocking highs that cause rapid fuel drying. Climate controls the area burned through changing the dynamics of large-scale teleconnection patterns (Pacific Decadal Oscillation/El Niño Southern Oscillation and Arctic Oscillation, PDO/ENSO and AO) that control the frequency of blocking highs over the continent at different time scales. Changes in these teleconnections may be caused by the current global warming. Thus, an increase in temperature alone need not be associated with an increase in area burned in the North American boreal forest. Since the end of the Little Ice Age, the climate has been unusually moist and variable: large fire years have occurred in unusual years, fire frequency has decreased and fire-climate relationships have occurred at interannual to decadal time scales. Prolonged and severe droughts were common in the past and were partly associated with changes in the PDO/ENSO system. Under these conditions, large fire years become common, fire frequency increases and fire-climate relationships occur at decadal to centennial time scales. A suggested return to the drier climate regimes of the past would imply major changes in the temporal dynamics of fire-climate relationships and in area burned, a reduction in the mean age of the forest, and changes in species composition of the North American boreal forest.

Patterns of tropical Pacific convection anomalies and associated extratropical wave trains in AMIP5

NASA Astrophysics Data System (ADS)

Ding, Shuoyi; Chen, Wen; Graf, Hans-F.; Guo, Yuanyuan

2018-05-01

In this paper, the performance of 18 Coupled Model Intercomparison Project Phase 5 (CMIP5) models forced by observational SSTs in simulating the tropical Pacific convective variation and the atmospheric responses in the extratropics are assessed. The multi-model ensemble mean results of 18 CMIP5 models show that five major patterns of tropical Pacific convection anomaly in winter can indeed be well reproduced, however, the simulation of the corresponding extratropical responses for each pattern exists some deficiency except for the La Niña pattern compared with observations. We defined an optimized subset of well performing models (ACCESS1.0, CanAM4, CCSM4, CMCC-CM, HadGEM2-A, MPI-ESM-MR) in tropical Pacific deep convection according to the ranking of model skill score. These models exhibit approximately identical convection anomaly patterns in both amplitude and spatial structure to the observation, which potentially might improve the representation of extratropical teleconnections with the tropical Pacific, especially for the CP El Niño (CPEN), EP El Niño (EPEN) and western CP (W-CP) patterns. Both evident atmospheric anomalies of CPEN and EPEN patterns over the NA/E sector and the northeastward propagating wave trains of W-CP pattern can be quite well simulated in the high-skilled models.

Sensitivity of a cloud parameterization package in the National Center for Atmospheric Research Community Climate Model

NASA Astrophysics Data System (ADS)

Kao, C.-Y. J.; Smith, W. S.

1999-05-01

A physically based cloud parameterization package, which includes the Arakawa-Schubert (AS) scheme for subgrid-scale convective clouds and the Sundqvist (SUN) scheme for nonconvective grid-scale layered clouds (hereafter referred to as the SUNAS cloud package), is incorporated into the National Center for Atmospheric Research (NCAR) Community Climate Model, Version 2 (CCM2). The AS scheme is used for a more reasonable heating distribution due to convective clouds and their associated precipitation. The SUN scheme allows for the prognostic computation of cloud water so that the cloud optical properties are more physically determined for shortwave and longwave radiation calculations. In addition, the formation of anvil-like clouds from deep convective systems is able to be simulated with the SUNAS package. A 10-year simulation spanning the period from 1980 to 1989 is conducted, and the effect of the cloud package on the January climate is assessed by comparing it with various available data sets and the National Center for Environmental Protection/NCAR reanalysis. Strengths and deficiencies of both the SUN and AS methods are identified and discussed. The AS scheme improves some aspects of the model dynamics and precipitation, especially with respect to the Pacific North America (PNA) pattern. CCM2's tendency to produce a westward bias of the 500 mbar stationary wave (time-averaged zonal anomalies) in the PNA sector is remedied apparently because of a less "locked-in" heating pattern in the tropics. The additional degree of freedom added by the prognostic calculation of cloud water in the SUN scheme produces interesting results in the modeled cloud and radiation fields compared with data. In general, too little cloud water forms in the tropics, while excessive cloud cover and cloud liquid water are simulated in midlatitudes. This results in a somewhat degraded simulation of the radiation budget. The overall simulated precipitation by the SUNAS package is, however, substantially improved over the original CCM2.

Genotype-specific signal generation based on digestion of 3-way DNA junctions: application to KRAS variation detection.

PubMed

Amicarelli, Giulia; Adlerstein, Daniel; Shehi, Erlet; Wang, Fengfei; Makrigiorgos, G Mike

2006-10-01

Genotyping methods that reveal single-nucleotide differences are useful for a wide range of applications. We used digestion of 3-way DNA junctions in a novel technology, OneCutEventAmplificatioN (OCEAN) that allows sequence-specific signal generation and amplification. We combined OCEAN with peptide-nucleic-acid (PNA)-based variant enrichment to detect and simultaneously genotype v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) codon 12 sequence variants in human tissue specimens. We analyzed KRAS codon 12 sequence variants in 106 lung cancer surgical specimens. We conducted a PNA-PCR reaction that suppresses wild-type KRAS amplification and genotyped the product with a set of OCEAN reactions carried out in fluorescence microplate format. The isothermal OCEAN assay enabled a 3-way DNA junction to form between the specific target nucleic acid, a fluorescently labeled "amplifier", and an "anchor". The amplifier-anchor contact contains the recognition site for a restriction enzyme. Digestion produces a cleaved amplifier and generation of a fluorescent signal. The cleaved amplifier dissociates from the 3-way DNA junction, allowing a new amplifier to bind and propagate the reaction. The system detected and genotyped KRAS sequence variants down to approximately 0.3% variant-to-wild-type alleles. PNA-PCR/OCEAN had a concordance rate with PNA-PCR/sequencing of 93% to 98%, depending on the exact implementation. Concordance rate with restriction endonuclease-mediated selective-PCR/sequencing was 89%. OCEAN is a practical and low-cost novel technology for sequence-specific signal generation. Reliable analysis of KRAS sequence alterations in human specimens circumvents the requirement for sequencing. Application is expected in genotyping KRAS codon 12 sequence variants in surgical specimens or in bodily fluids, as well as single-base variations and sequence alterations in other genes.

DNA-Templated Polymerization of Side-Chain-Functionalized Peptide Nucleic Acid Aldehydes

PubMed Central

Kleiner, Ralph E.; Brudno, Yevgeny; Birnbaum, Michael E.; Liu, David R.

2009-01-01

The DNA-templated polymerization of synthetic building blocks provides a potential route to the laboratory evolution of sequence-defined polymers with structures and properties not necessarily limited to those of natural biopolymers. We previously reported the efficient and sequence-specific DNA-templated polymerization of peptide nucleic acid (PNA) aldehydes. Here, we report the enzyme-free, DNA-templated polymerization of side-chain-functionalized PNA tetramer and pentamer aldehydes. We observed that the polymerization of tetramer and pentamer PNA building blocks with a single lysine-based side chain at various positions in the building block could proceed efficiently and sequence-specifically. In addition, DNA-templated polymerization also proceeded efficiently and in a sequence-specific manner with pentamer PNA aldehydes containing two or three lysine side chains in a single building block to generate more densely functionalized polymers. To further our understanding of side-chain compatibility and expand the capabilities of this system, we also examined the polymerization efficiencies of 20 pentamer building blocks each containing one of five different side-chain groups and four different side-chain regio- and stereochemistries. Polymerization reactions were efficient for all five different side-chain groups and for three of the four combinations of side-chain regio- and stereochemistries. Differences in the efficiency and initial rate of polymerization correlate with the apparent melting temperature of each building block, which is dependent on side-chain regio- and stereochemistry, but relatively insensitive to side-chain structure among the substrates tested. Our findings represent a significant step towards the evolution of sequence-defined synthetic polymers and also demonstrate that enzyme-free nucleic acid-templated polymerization can occur efficiently using substrates with a wide range of side-chain structures, functionalization positions within each building block, and functionalization densities. PMID:18341334

Characterization of functional variables in epididymal alpaca (Vicugna pacos) sperm using imaging flow cytometry.

PubMed

Santiani, Alexei; Ugarelli, Alejandra; Evangelista-Vargas, Shirley

2016-10-01

Epididymal alpaca sperm represent an alternative model for the study of alpaca semen. The objective of this study was to characterize the normal values of some functional variables in epididymal alpaca sperm using imaging flow cytometry. Alpaca testicles (n=150) were processed and sperm were recovered from the cauda epididymides. Only 76 samples with acceptable motility and sperm count were considered for assessment by imaging flow cytometry. Acrosome integrity and integrity/viability were assessed by FITC-PSA/PI and FITC-PNA/PI. Mitochondrial membrane potential (MMP) was assessed by MitoTracker CMXRos and MitoTracker Deep Red FM. Lipid peroxidation was evaluated using BODIPY 581/591 C11. Results show that the mean values for acrosome-intact sperm were 95.03±6.39% and 93.34±7.96%, using FITC-PSA and FITC-PNA, respectively. The mean values for acrosome-intact viable sperm were 60.58±12.12% with FITC-PSA/PI and 58.81±12.94% with FITC-PNA/PI. Greater MMP was detected in 65.03±15.92% and 59.52±19.19%, using MitoTracker CMXRos and MitoTracker Deep Red FM, respectively. Lipid peroxidation was 0.84±0.95%. Evaluation of acrosome-intact and acrosome-intact viable sperm with FITC-PSA/PI compared with. FITC-PNA/PI or MMP with MitoTracker CMXRos compared with MitoTracker Deep Red FM were correlated (P<0.05). The MMP using MitoTracker CMXRos was the only variable correlated (P<0.05) with sperm motility (r=0.3979). This report provides a basis for future research related to alpaca semen using the epididymal sperm model. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication of a Horizontal and a Vertical Large Surface Area Nanogap Electrochemical Sensor

PubMed Central

Hammond, Jules L.; Rosamond, Mark C.; Sivaraya, Siva; Marken, Frank; Estrela, Pedro

2016-01-01

Nanogap sensors have a wide range of applications as they can provide accurate direct detection of biomolecules through impedimetric or amperometric signals. Signal response from nanogap sensors is dependent on both the electrode spacing and surface area. However, creating large surface area nanogap sensors presents several challenges during fabrication. We show two different approaches to achieve both horizontal and vertical coplanar nanogap geometries. In the first method we use electron-beam lithography (EBL) to pattern an 11 mm long serpentine nanogap (215 nm) between two electrodes. For the second method we use inductively-coupled plasma (ICP) reactive ion etching (RIE) to create a channel in a silicon substrate, optically pattern a buried 1.0 mm × 1.5 mm electrode before anodically bonding a second identical electrode, patterned on glass, directly above. The devices have a wide range of applicability in different sensing techniques with the large area nanogaps presenting advantages over other devices of the same family. As a case study we explore the detection of peptide nucleic acid (PNA)−DNA binding events using dielectric spectroscopy with the horizontal coplanar device. PMID:27983655

El Niño-like teleconnection increases California precipitation in response to warming

PubMed Central

Allen, Robert J.; Luptowitz, Rainer

2017-01-01

Future California (CA) precipitation projections, including those from the most recent Climate Model Intercomparison Project (CMIP5), remain uncertain. This uncertainty is related to several factors, including relatively large internal climate variability, model shortcomings, and because CA lies within a transition zone, where mid-latitude regions are expected to become wetter and subtropical regions drier. Here, we use a multitude of models to show CA may receive more precipitation in the future under a business-as-usual scenario. The boreal winter season-when most of the CA precipitation increase occurs-is associated with robust changes in the mean circulation reminiscent of an El Niño teleconnection. Using idealized simulations with two different models, we further show that warming of tropical Pacific sea surface temperatures accounts for these changes. Models that better simulate the observed El Niño-CA precipitation teleconnection yield larger, and more consistent increases in CA precipitation through the twenty-first century. PMID:28681837

Indian summer monsoon variability forecasts in the North American multimodel ensemble

NASA Astrophysics Data System (ADS)

Singh, Bohar; Cash, Ben; Kinter, James L., III

2018-04-01

The representation of the seasonal mean and interannual variability of the Indian summer monsoon rainfall (ISMR) in nine global ocean-atmosphere coupled models that participated in the North American Multimodal Ensemble (NMME) phase 1 (NMME:1), and in nine global ocean-atmosphere coupled models participating in the NMME phase 2 (NMME:2) from 1982-2009, is evaluated over the Indo-Pacific domain with May initial conditions. The multi-model ensemble (MME) represents the Indian monsoon rainfall with modest skill and systematic biases. There is no significant improvement in the seasonal forecast skill or interannual variability of ISMR in NMME:2 as compared to NMME:1. The NMME skillfully predicts seasonal mean sea surface temperature (SST) and some of the teleconnections with seasonal mean rainfall. However, the SST-rainfall teleconnections are stronger in the NMME than observed. The NMME is not able to capture the extremes of seasonal mean rainfall and the simulated Indian Ocean-monsoon teleconnections are opposite to what are observed.

El Niño-like teleconnection increases California precipitation in response to warming

NASA Astrophysics Data System (ADS)

Allen, Robert J.; Luptowitz, Rainer

2017-07-01

Future California (CA) precipitation projections, including those from the most recent Climate Model Intercomparison Project (CMIP5), remain uncertain. This uncertainty is related to several factors, including relatively large internal climate variability, model shortcomings, and because CA lies within a transition zone, where mid-latitude regions are expected to become wetter and subtropical regions drier. Here, we use a multitude of models to show CA may receive more precipitation in the future under a business-as-usual scenario. The boreal winter season-when most of the CA precipitation increase occurs-is associated with robust changes in the mean circulation reminiscent of an El Niño teleconnection. Using idealized simulations with two different models, we further show that warming of tropical Pacific sea surface temperatures accounts for these changes. Models that better simulate the observed El Niño-CA precipitation teleconnection yield larger, and more consistent increases in CA precipitation through the twenty-first century.

Comparison of sea level pressure reconstructions from western North American tree rings with a proxy record of winter severity in Japan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, G.A.; Lough, J.M.; Fritts, H.C.

Reconstructions of winter (December-February) sea level pressure (SLP) from western North American tree-ring chronologies are compared with a proxy record of winter severity in Japan derived from the historically documented freeze dates of Lake Suwa. The SLP reconstructions extend from 1602 to 1961 and freeze dates from 1443 to 1954. The instrumental and reconstructed SLP for the 20th century reveal two distinct circulation regimes (teleconnection patterns) over the North Pacific that appear to be associated with severe and mild winters and, consequently, with early and late freezing of the lake. The reconstructed SLPO anomaly map for severe winters prior tomore » 1683 shows a pattern similar to those in the instrumental and reconstructed records of the 20th century. The analysis reveals that the reliability of the reconstruction may vary with the configuration of the actual SLP pattern as the mild winter pattern is not as well reconstructed as the severe winter pattern. That result illustrates the importance of testing the reliability of a reconstruction within the context of the intended interpretation. This analysis demonstrates how different types of proxy climate data can be compared and verified.« less

SWH trends and links to large scale teleconnection patterns in the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Lionello, P.; Pino, C.; Galati, M. B.

2010-09-01

This study analyzes the SWH field in the Mediterranean Sea using a multidecadal simulations (1958-2001) carried out using the WAM (WAve Model) forced by the REMO-HIPOCAS wind fields. The simulations are validated against satellite altimeter data. Several mid-latitude patterns are linked to the SWH field in the Mediterranean. Considering the mean monthly SWH values, EA (Eastern Atlantic pattern) exerts the largest influence, while NAO and other patterns have a smaller but comparable effect. Severe SWH conditions have been characterized using the 95percentile of daily SWH maxima. NAO is important mainly for high SWH conditions in winter with significant correlation in December, January and March, but also EA, SCA (SCAndinavian) and EA-WR (Eastern Atlantic-Western Russia) play an important role. In general, both SWH high and mean values are modulated by several patterns, with an important variability in space and at monthly level so that no single pattern can be attributed a dominant role along the whole annual cycle and all the mentioned patterns are important for at least few months in the year. Significant trends of SWH are present only in sparse areas and suggest mostly a minor decrease of storm intensity, The statistics of extremes and high SWH values is substantially steady during the second half of the 20th century.

Detection of group B streptococci in Lim broth by use of group B streptococcus peptide nucleic acid fluorescent in situ hybridization and selective and nonselective agars.

PubMed

Montague, Naomi S; Cleary, Timothy J; Martinez, Octavio V; Procop, Gary W

2008-10-01

The sensitivity, specificity, and positive and negative predictive values for the detection of group B streptococci from Lim enrichment broth with sheep blood agar (SBA), with selective Streptococcus agar (SSA), and by a peptide nucleic acid fluorescent in situ hybridization (PNA FISH) assay were as follows: for culture on SBA, 68.4%, 100%, 100%, and 87.9%, respectively; for culture on SSA, 85.5%, 100%, 100%, and 94.1%, respectively; and for the PNA FISH assay, 97.4%, 98.3%, 96.1%, and 98.9%, respectively.

Detection of Group B Streptococci in Lim Broth by Use of Group B Streptococcus Peptide Nucleic Acid Fluorescent In Situ Hybridization and Selective and Nonselective Agars▿

PubMed Central

Montague, Naomi S.; Cleary, Timothy J.; Martinez, Octavio V.; Procop, Gary W.

2008-01-01

The sensitivity, specificity, and positive and negative predictive values for the detection of group B streptococci from Lim enrichment broth with sheep blood agar (SBA), with selective Streptococcus agar (SSA), and by a peptide nucleic acid fluorescent in situ hybridization (PNA FISH) assay were as follows: for culture on SBA, 68.4%, 100%, 100%, and 87.9%, respectively; for culture on SSA, 85.5%, 100%, 100%, and 94.1%, respectively; and for the PNA FISH assay, 97.4%, 98.3%, 96.1%, and 98.9%, respectively. PMID:18667597

Tethered particle analysis of supercoiled circular DNA using peptide nucleic acid handles.

PubMed

Norregaard, Kamilla; Andersson, Magnus; Nielsen, Peter Eigil; Brown, Stanley; Oddershede, Lene B

2014-09-01

This protocol describes how to monitor individual naturally supercoiled circular DNA plasmids bound via peptide nucleic acid (PNA) handles between a bead and a surface. The protocol was developed for single-molecule investigation of the dynamics of supercoiled DNA, and it allows the investigation of both the dynamics of the molecule itself and of its interactions with a regulatory protein. Two bis-PNA clamps designed to bind with extremely high affinity to predetermined homopurine sequence sites in supercoiled DNA are prepared: one conjugated with digoxigenin for attachment to an anti-digoxigenin-coated glass cover slide, and one conjugated with biotin for attachment to a submicron-sized streptavidin-coated polystyrene bead. Plasmids are constructed, purified and incubated with the PNA handles. The dynamics of the construct is analyzed by tracking the tethered bead using video microscopy: less supercoiling results in more movement, and more supercoiling results in less movement. In contrast to other single-molecule methodologies, the current methodology allows for studying DNA in its naturally supercoiled state with constant linking number and constant writhe. The protocol has potential for use in studying the influence of supercoils on the dynamics of DNA and its associated proteins, e.g., topoisomerase. The procedure takes ~4 weeks.

Fluorescence emission and polarization analyses for evaluating binding of ruthenium metalloglycoclusters to lectins and tetanus toxin C-fragment

NASA Astrophysics Data System (ADS)

Okada, Tomoko; Minoura, Norihiko

2011-03-01

We develop a fluorescent ruthenium metalloglycocluster for use as a powerful molecular probe in evaluating the binding between carbohydrates and lectins by fluorescence emission (FE) and fluorescence polarization (FP) analyses. Changes in the FE and FP of these metalloglycoclusters are measured following the addition of lectin [peanut agglutinin (PNA), Ricinus communis agglutinin 120, Concanavalin A (ConA), or wheat germ agglutinin] or tetanus toxin c-fragment (TCF). After the addition of PNA, the FE spectrum of [Ru(bpy-2Gal)3] shows a new emission peak and the FP value of [Ru(bpy-2Gal)3] increases. Similarly, the FE spectrum of [Ru(bpy-2Glc)3] shows a new emission peak and the FP value increases on addition of ConA. Because other combinations of metalloglycoclusters and lectins show little change, specific binding of galactose to PNA and that of glucose to ConA are confirmed by the FE and FP measurements. Resulting dissociation constants (Kd) prove that the metalloglycoclusters with highly clustered carbohydrates show higher affinity for the respective lectins than those with less clustered carbohydrates. Furthermore, specific binding of [Ru(bpy-2Gal)3] to TCF was confirmed by the FP measurement.

DNA biosensors implemented on PNA-functionalized microstructured optical fibers Bragg gratings

NASA Astrophysics Data System (ADS)

Candiani, A.; Giannetti, S.; Cucinotta, A.; Bertucci, A.; Manicardi, A.; Konstantaki, M.; Margulis, W.; Pissadakis, S.; Corradini, R.; Selleri, S.

2013-05-01

A novel DNA sensing platform based on a Peptide Nucleic Acid - functionalized Microstructured Optical Fibers gratings has been demonstrated. The inner surface of different MOFs has been functionalized using PNA probes, OligoNucleotides mimic that are well suited for specific DNA target sequences detection. The hybrid sensing systems were tested for optical DNA detection of targets of relevance in biomedical application, using the cystic fibrosis gene mutation, and food-analysis, using the genomic DNA from genetic modified organism soy flour. After the solutions of DNA molecules has been infiltrated inside the fibers capillaries and hybridization has occurred, oligonucleotidefunctionalized gold nanoparticles were infiltrated and used to form a sandwich-like system to achieve signal amplification. Spectral measurements of the reflected signal reveal a clear wavelength shift of the reflected modes when the infiltrated complementary DNA matches with the PNA probes placed on the inner fiber surface. Measurements have also been made using the mismatched DNA solution for the c, containing a single nucleotide polymorphism, showing no significant changes in the reflected spectrum. Several experiments have been carried out demonstrating the reproducibility of the results and the high selectivity of the sensors, showing the simplicity and the potential of this approach.

Monitoring the Transcriptional Activity of Human Endogenous Retroviral HERV-W Family Using PNA Strand Invasion into Double-Stranded DNA.

PubMed

Machnik, Grzegorz; Skudrzyk, Estera; Bułdak, Łukasz; Ruczyński, Jarosław; Kozłowska, Agnieszka; Mucha, Piotr; Rekowski, Piotr; Szkróbka, Witold; Basiak, Marcin; Bołdys, Aleksandra; Sławska, Helena; Okopień, Bogusław

2018-02-01

In the presented assay, we elaborated a method for distinguishing sequences that are genetically closely related to each other. This is particularly important in a situation where a fine balance of the allele abundance is a point of research interest. We developed a peptide nucleic acid (PNA) strand invasion technique for the differentiation between multiple sclerosis-associated retrovirus (MSRV) and ERVWE1 sequences, both molecularly similar, belonging to the human endogenous retrovirus HERV-W family. We have found that this method may support the PCR technique in screening for minor alleles which, in certain conditions, may be undetected by the standard PCR technique. We performed the analysis of different ERVWE1 and MSRV template mixtures ranging from 0 to 100% of ERVWE1 in the studied samples, finding the linear correlation between template composition and signal intensity of final reaction products. Using the PNA strand invasion assay, we were able to estimate the relative ERVWE1 expression level in human specimens such as U-87 MG, normal human astrocytes cell lines and placental tissue. The results remained in concordance with those obtained by semi-quantitative or quantitative PCR.

The effect of acamprosate on alcohol and food craving in patients with alcohol dependence.

PubMed

Han, Doug Hyun; Lyool, In Kyoon; Sung, Young Hoon; Lee, Sang Hoon; Renshaw, Perry F

2008-03-01

The balance between inhibitory (gamma aminobutyric acid; GABAergic) and excitatory (glutamatergic) neurotransmission is thought to be associated with craving for alcohol and food. The anticraving effect of acamprosate is thought to be mediated through modifying the balance of GABA and glutamate. Recent studies in animals have suggested that acamprosate may have non-selective effects on craving for both alcohol and food. The influence of acamprosate for reducing craving for alcohol and food was assessed in 204 in-patients with alcohol dependence (96 patients treated with acamprosate, PWA; 108 patients were not treated PNA) was assessed at baseline and following 1, 2, and 4 weeks of treatment. There was a significant reduction in craving for alcohol over 4 weeks of treatment in both PWA and PNA groups, but without significant group differences. In contrast, a reduction in food craving was observed only in the PWA group. In addition, there was a significant increase of body mass index (BMI) in the PNA group but not the PWA group over the 4-week period. These results demonstrate acamprosate nonselective effects on craving for drinking and eating in alcoholic patients.

Fischer carbene mediated covalent grafting of a peptide nucleic acid on gold surfaces and IR optical detection of DNA hybridization with a transition metalcarbonyl label

NASA Astrophysics Data System (ADS)

Srivastava, Pratima; Ghasemi, Mahsa; Ray, Namrata; Sarkar, Amitabha; Kocabova, Jana; Lachmanova, Stepanka; Hromadova, Magdalena; Boujday, Souhir; Cauteruccio, Silvia; Thakare, Pramod; Licandro, Emanuela; Fosse, Céline; Salmain, Michèle

2016-11-01

Amine-reactive surfaces comprising N-hydroxysuccinimide ester groups as well as much more unusual Fischer alkoxymetallocarbene groups were generated on gold-coated surfaces via self-assembled monolayers of carboxy- and azido-terminated thiolates, respectively. These functions were further used to immobilize homothymine peptide nucleic acid (PNA) decamer in a covalent fashion involving the primary amine located at its N-terminus. These stepwise processes were monitored by polarization modulation reflection - absorption infrared spectroscopy (PM-RAIRS) that gave useful information on the molecular composition of the organic layers. PNA grafting and hybridization with complementary DNA strand were successfully transduced by quartz crystal microbalance (QCM) measurements. Unfortunately, attempts to transduce the hybridization optically by IR in a label-free fashion were inconclusive. Therefore we undertook to introduce an IR reporter group, namely a transition metalcarbonyl (TMC) entity at the 5‧ terminus of complementary DNA. Evidence for the formation of PNA-DNA heteroduplex was brought by the presence of ν(Ctbnd O) bands in the 2000 cm-1 region of the IR spectrum of the gold surface owing to the metalcarbonyl label.

A safe and reliable neutralization assay based on pseudovirus to measure neutralizing antibody titer against poliovirus.

PubMed

Liu, Shaohua; Song, Dongmei; Bai, Han; Lu, Weiwei; Dai, Xinxian; Hao, Chunsheng; Zhang, Zhongyang; Guo, Huijie; Zhang, Yue; Li, Xiuling

2017-12-01

With the promotion of inactivated poliomyelitis vaccine (IPV) and live attenuated oral poliomyelitis vaccine (OPV), the global reported cases of poliomyelitis have reduced sharply from 0.35 million in 1988 to 74 in 2015. The Polio Eradication & Endgame Strategic Plan published by WHO in 2013 included the strategy of implementation of poliovirus safe handling and containment measures to minimize the risks of facility-associated reintroduction of virus into the polio-free community to prevent the re-import of poliovirus. Toward this strategy, we produced replication-incompetent pseudovirus of poliovirus type 1, 2, 3 attenuated strains by constructing poliovirus capsid expression vectors and poliovirus replicon then transfecting HEK293T cells and developed a pseudovirus-based neutralization assay (pNA) to determine neutralizing antibody titer which is more secure, time-saving and reliable than conventional neutralization assay (cNA). By using anti-poliovirus rat serum, we demonstrated excellent correlation between neutralizing antibody titers measured by cNA and pNA. It was concluded that pNA can be a potential alternative to replace cNA as a safe and time-saving system for titer determination after live poliovirus's safekeeping. © 2017 Wiley Periodicals, Inc.

Growth of binary organic NLO crystals: m.NA-p.NA and m.NA-CNA system

NASA Technical Reports Server (NTRS)

Singh, N. B.; Henningsen, T.; Hopkins, R. H.; Mazelsky, R.

1993-01-01

Experiments were carried out to grow 3.Nitroaniline (m.NA) crystals doped with 4.Nitroaniline (p.NA) and 2.chloro 4.Nitroaniline (CNA). The measured undercooling for m.NA, p.NA, and CNA were 0.21 tm K, 0.23 tm K, and 0.35 tm K respectively, where tm represents the melting temperature of the pure component. Because of the crystals' large heat of fusion and large undercooling, it was not possible to grow good quality crystals with low thermal gradients. In the conventional two-zone Bridgman furnace we had to raise the temperature of the hot zone above the decomposition temperature of CNA, p.NA, and m.NA to achieve the desired thermal gradient. To avoid decomposition, we used an unconventional Bridgman furnace. Two immiscible liquids, silicone oil and ethylene glycol, were used to build a special two-zone Bridgman furnace. A temperature gradient of 18 K/cm was achieved without exceeding the decomposition temperature of the crystal. The binary crystals, m.NA-p.NA and m.NA-CNA, were grown in centimeter size in this furnace. X-ray and optical characterization showed good optical quality.

Functionalization of DNA Nanostructures for Cell Signaling Applications

NASA Astrophysics Data System (ADS)

Pedersen, Ronnie O.

Transforming growth factor beta (TGF-beta) is an important cytokine responsible for a wide range of different cellular functions including extracellular matrix formation, angiogenesis and epithelial-mesenchymal transition. We have sought to use self-assembling DNA nanostructures to influence TGF-beta signaling. The predictable Watson Crick base pairing allows for designing self-assembling nanoscale structures using oligonucleotides. We have used the method of DNA origami to assemble structures functionalized with multiple peptides that bind TGF-beta receptors outside the ligand binding domain. This allows the nanostructures to cluster TGF-beta receptors and lower the energy barrier of ligand binding thus sensitizing the cells to TGF-beta stimulation. To prove efficacy of our nanostructures we have utilized immunofluorescent staining of Smad2/4 in order to monitor TGF-beta mediated translocation of Smad2/4 to the cell nucleus. We have also utilized Smad2/4 responsive luminescence constructs that allows us to quantify TGF-beta stimulation with and without nanostructures. To functionalize our nanostructures we relied on biotin-streptavidin linkages. This introduces a multivalency that is not necessarily desirable in all designs. Therefore we have investigated alternative means of functionalization. The first approach is based on targeting DNA nanostructure by using zinc finger binding proteins. Efficacy of zinc finger binding proteins was assayed by the use of enzyme-linked immunosorbent (ELISA) assay and atomic force microscopy (AFM). While ELISA indicated a relative specificity of zinc finger proteins for target DNA sequences AFM showed a high degree of non-specific binding and insufficient affinity. The second approach is based on using peptide nucleic acid (PNA) incorporated in the nanostructure through base pairing. PNA is a synthetic DNA analog consisting of a backbone of repeating N-(2-aminoethyl)-glycine units to which purine and pyrimidine bases are linked by amide bonds. The solid phase synthesis of PNA allows for convenient extension of the backbone into a peptide segment enabling peptide functionalization of DNA nanostructures. We have investigated how the neutral character of PNA alters the incorporation in DNA based nanostructures compared to a DNA control using biotinylation and AFM. Results indicate that PNA can successfully be used as a way of functionalizing DNA nanostructures. Additionally we have shown that functionalized nanostructures are capable of sensitizing cells to TGF-beta stimulation.

Tendencies of extreme values on rainfall and temperature and its relationship with teleconnection patterns

NASA Astrophysics Data System (ADS)

Taboada, J. J.; Cabrejo, A.; Guarin, D.; Ramos, A. M.

2009-04-01

It is now very well established that yearly averaged temperatures are increasing due to anthropogenic climate change. In the area of Galicia (NW Spain) this trend has also been determined. Rainfall does not show a clear tendency in its yearly accumulated values. The aim of this work is to study different extreme indices of rainfall and temperatures analysing variability and possible trends associated to climate change. Station data for the study was provided by the CLIMA database of the regional government of Galicia (NW Spain). The definition of the extreme indices was taken from the joint CCl/CLIVAR/JCOMM Expert Team (ET) on Climate Change Detection and Indices (ETCCDI) This group has defined a set of standard extreme values to simplify intercomparison of data from different regions of the world. For the temperatures in the period 1960-2006, results show a significant increase of the number of days with maximum temperatures above the 90th percentile. Furthermore, a significant decrease of the days with maximum temperatures below the 10th percentile has been found. The tendencies of minimum temperatures are reverse: fewer nights with minimum temperatures below 10th percentile, and more with minimum temperatures above 90th percentile. Those tendencies can be observed all over the year, but are more pronounced in summer. This trend is expected to continue in the next decades because of anthropogenic climate change. We have also calculated the relationship between the above mentioned extreme values and different teleconnection patterns appearing in the North Atlantic area. Results show that local tendencies are associated with trends of EA (Eastern Atlantic) and SCA (Scandinavian) patterns. NAO (North Atlantic Oscillation) has also some relationship with these tendencies, but only related with cold days and nights in winter. Rainfall index do not show any clear tendency on the annual scale. Nevertheless, the count of days when precipitation is greater than 20mm (R20mm) and the total precipitation when rainfall is greater than 95th percentile (R95pTOT) diminishes in winter and spring, but increases in autumn. This trend is related with NAO in winter and spring and with SCA in autumn.

Precipitation response to the current ENSO variability in a warming world

NASA Astrophysics Data System (ADS)

Bonfils, C.; Santer, B. D.; Phillips, T. J.; Marvel, K.; Leung, L.

2013-12-01

The major triggers of past and recent droughts include large modes of variability, such as ENSO, as well as specific and persistent patterns of sea surface temperature anomalies (SSTAs; Hoerling and Kumar, 2003, Shin et al. 2010, Schubert et al. 2009). However, alternative drought initiators are also anticipated in response to increasing greenhouse gases, potentially changing the relative contribution of ocean variability as drought initiator. They include the intensification of the current zonal wet-dry patterns (the thermodynamic mechanism, Held and Soden, 2006), a latitudinal redistribution of global precipitation (the dynamical mechanism, Seager et al. 2007, Seidel et al. 2008, Scheff and Frierson 2008) and a reduction of local soil moisture and precipitation recycling (the land-atmosphere argument). Our ultimate goal is to investigate whether the relative contribution of those mechanisms change over time in response to global warming. In this study, we first perform an EOF analysis of the 1900-1999 time series of observed global SST field and identify a simple ENSO-like (ENSOL) mode of SST variability. We show that this mode is well spatially and temporally correlated with observed worldwide regional precipitation and drought variability. We then develop concise metrics to examine the fidelity with which the CMIP5 coupled global climate models (CGCMs) capture this particular ENSO-like mode in the current climate, and their ability to replicate the observed teleconnections with precipitation. Based on the CMIP5 model projections of future climate change, we finally analyze the potential temporal variations in ENSOL to be anticipated under further global warming, as well as their associated teleconnections with precipitation (pattern, amplitude, and total response). Overall, our approach allows us to determine what will be the effect of the current ENSO-like variability (i.e., as measured with instrumental observations) on precipitation in a warming world. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and is supported, among others, by C.B. Early Career Research Program award.

Spatial and temporal Teleconnections of Sea Surface Temperature and Ocean Indices to regional Climate Variations across Thailand - a Pathway to understanding the Impact of Climate Change on Water Resources

NASA Astrophysics Data System (ADS)

Bejranonda, Werapol; Koch, Manfred

2010-05-01

Thailand has a long coastline with the Pacific Ocean, as part of the Gulf of Thailand, as well as with the Indian Ocean, as part of the Andaman Sea. Because of this peculiar location, Thailand's local climate and, in particular, its water resources are strongly influenced by the mix of tropical wet, tropical dry and tropical monsoon seasons. Because of the large seasonal and interannual variations and irregularities of these, mainly ocean-driven weather patterns, particularly in recent times, large-scale water storage in huge river-fed reservoirs has a long tradition in Thailand, providing water for urban, industrial and agricultural use during long dry seasonal periods. These reservoirs which are located all over Thailand gather water primarily from monsoon-driven rainfall during the wet season which, usually, lasts from May to October. During the dry season, November to April, when the monsoon winds move northward, the air masses are drier in central and northern Thailand, with rain falling here only a few days in a month. Southern Thailand, on the other hand, which is constituted mostly by the isthmus between the two oceans, stays even hot and humid during that time period. Because of this tropical climate pattern, the surface water resources in most of Thailand strongly hinge on the monsoon movements which, in turn, depend themselves upon the thermal states of the Pacific and Indian Oceans. Therefore, the understanding of the recent strong seasonal and interannual climate variations with their detrimental effects on the availability of hydrological water resources in most parts of Thailand, must include the analysis of changes of various sea-state indices in the adjacent oceans and of their possible teleconnections with regional climate indices across this country. With the modern coupled atmospheric-ocean models being able to predict the variations of many ocean indices over a period of several months, namely, those driven by El Nino- Southern Oscillations (ENSO) events in the Pacific Ocean, if such teleconnections exist, one would have would have a powerful tool at hand to forecast extreme seasonal climate pattern across Thailand over a limited time period. Eventually, such a predictive tool would help to better manage the availability and adequate supply of surface water resources to the various water users in this country. In the present study the spatial and temporal relationships between the global climate circulation system and the regional weather in Thailand are assessed by various techniques of stochastic time series analysis. More specifically, the time series of the sea surface temperature (SST) and various ocean indices of the Pacific and the Indian Oceans, as well as the time series of 121 meteorological stations from 5 regions across Thailand which include humidity, evaporation, temperature and rainfall during 1950-2007 are examined using autocorrelation, ARIMA, Wavelet Transform methods. Possible teleconnections between the behaviour of the ocean states and the climate variations at meteorological stations in eastern Thailand which frequently suffers from water shortage problems are analyzed using regression, cross-correlation and the Wavelet cross-correlation method. In addition to the time series of the observed ocean and meteorological variables, 1961-2000 CGCM3 predictors of the macro-scale regional climate variations for this study area are analyzed by the methods above and correlated with the ocean indices as well. Rainfall and temperatures at selected stations are forecasted up to year 2007 using the teleconnection- relationships found by multiple linear regression with the CGCM3 predictors. In addition, autoregressive integrated moving average (ARIMA) models of these climate variable are set up that are eventually extended to include the ocean indices as external regressors. The results of these various statistical techniques show that the El-Niño 1.2 SST anomaly indice of the Pacific Ocean, which refers to the most eastern section of the Pacific, correlates the strongest with the Thai local climate. Through cross-correlation, the most sensitive parameters to the ocean indices are the minimum temperature at stations in the northern and northeastern, inland regions of Thailand and the number of rainy days in the eastern, central and southern, coastal regions. In the southern region the amount of rainfall at the coast of Gulf of Thailand varies positively with El-Niño, but negatively for stations along the Andaman Sea coast in the west of the isthmus, with maximal correlation lag.-times of 4 months. Surprisingly the corresponding connections of the local climate variables with the Indian Ocean indices are less well established, with an optimal lag-time of only 3 months. Using the results of the teleconnection regression relationships, the forecast of the local climate variables could be improved significantly, as indicated by the Nash-Sutcliffe-coefficient of the prediction model's which increased from originally 0.30, 0.72 and 0.26 to 0.51, 0.82 and 0.46 for the rainfall, minimum and maximum temperatures, respectively. The results of our analysis indicate the possibility of a better forecast of extreme seasonal climate variations across some regions of Thailand over a limited time period by using short-term expected variations of the Pacific and Indian ocean indices.

Physical mechanisms of the summer precipitation variations in the Taklimakan and Gobi Desert

NASA Astrophysics Data System (ADS)

Huang, W.; Feng, S.; Chen, J.; Chen, F.

2013-12-01

The Taklimakan and the adjacent Gobi Desert (TD in short) in northwestern China is one of the most arid regions in the middle latitudes, where water is scarce year round. Using observational precipitation and the reanalysis data, this study investigated the variations of summer precipitation in TD and their association with water vapor flux and atmospheric circulation. Though the long-term mean water vapor is mostly comes from the west, the variations of summer precipitation in TD is dominated by the water vapor flux from the south, originated from the Arabian Sea. The anomalous water vapor flux is closely associated with the meridional teleconnection pattern around 50-80°E and the zonal teleconection pattern along the Asian westerly jet in summer. The meridional teleconnection connecting the Central Asia and the tropical Indian Ocean, and the zonal pattern resembles the ';Silk Road pattern'. The two wave trains connected in Central Asia. The anomalous pressure gradient force between negative height anomalies in Central Asia and the positive height anomalies in Arabian Sea/India and North Central China lead to anomalous ascending motion in TD and bring more water vapor from the Arabian Sea to pass over the Tibetan Plateau to fuel the precipitation development in the study region. These mechanisms lead to out-of-phase relationship between TD precipitation and Indian summer monsoon in the instrumental period and the past 2000 years. The vertically integrated summer water vapor flux (arrows) and 300hPa geopotential height (contour) regressed against the summer precipitation in TD during 1960-2010. Shadings (blue arrows) indicate the correlations between the geopotential height (water vapor flux) and the TD precipitation are significant at the 95% confidence level. The Guliya ice core is marked as star and the proxy monsoon records in Arabian Sea (box cores 723A and RC2730) are marked as triangles. Summer climatological water vapor budget and the correaltion between the water vapor budget and TD precipitaiton during 1960-2010. For climatological water vapor budget, the results shown are the total water vapor across the boundaries. Positive (negative) numbers indicate northward/eastward (southward/westward) water vapor flows. '*' and '**' indicate the correaltions between TD precipitation and water budget are significant at 95% and 99% confidence levels, respectively.

Large fluctuations of dissolved oxygen in the Indian and Pacific oceans during Dansgaard-Oeschger oscillations caused by variations of North Atlantic Deep Water subduction

USGS Publications Warehouse

Schmittner, A.; Galbraith, E.D.; Hostetler, S.W.; Pedersen, Thomas F.; Zhang, R.

2007-01-01

Paleoclimate records from glacial Indian and Pacific oceans sediments document millennial-scale fluctuations of subsurface dissolved oxygen levels and denitrification coherent with North Atlantic temperature oscillations. Yet the mechanism of this teleconnection between the remote ocean basins remains elusive. Here we present model simulations of the oxygen and nitrogen cycles that explain how changes in deepwater subduction in the North Atlantic can cause large and synchronous variations of oxygen minimum zones, throughout the Northern Hemisphere of the Indian and Pacific oceans, consistent with the paleoclimate records. Cold periods in the North Atlantic are associated with reduced nutrient delivery to the upper Indo-Pacific oceans, thereby decreasing productivity. Reduced export production diminishes subsurface respiration of organic matter leading to higher oxygen concentrations and less denitrification. This effect of reduced oxygen consumption dominates at low latitudes. At high latitudes in the Southern Ocean and North Pacific, increased mixed layer depths and steepening of isopycnals improve ocean ventilation and oxygen supply to the subsurface. Atmospheric teleconnections through changes in wind-driven ocean circulation modify this basin-scale pattern regionally. These results suggest that changes in the Atlantic Ocean circulation, similar to those projected by climate models to possibly occur in the centuries to come because of anthropogenic climate warming, can have large effects on marine ecosystems and biogeochemical cycles even in remote areas. Copyright 2007 by the American Geophysical Union.

Teleconnections, Midlatitude Cyclones and Aegean Sea Turbulent Heat Flux Variability on Daily Through Decadal Time Scales

NASA Technical Reports Server (NTRS)

Romanski, Joy; Romanou, Anastasia; Bauer, Michael; Tselioudis, George

2013-01-01

We analyze daily wintertime cyclone variability in the central and eastern Mediterranean during 1958-2001, and identify four distinct cyclone states, corresponding to the presence or absence of cyclones in each basin. Each cyclone state is associated with wind flows that induce characteristic patterns of cooling via turbulent (sensible and latent) heat fluxes in the eastern Mediterranean basin and Aegean Sea. The relative frequency of occurrence of each state determines the heat loss from the Aegean Sea during that winter, with largest heat losses occurring when there is a storm in the eastern but not central Mediterranean (eNOTc), and the smallest occurring when there is a storm in the central but not eastern Mediterranean (cNOTe). Time series of daily cyclone states for each winter allow us to infer Aegean Sea cooling for winters prior to 1985, the earliest year for which we have daily heat flux observations. We show that cyclone states conducive to Aegean Sea convection occurred in 1991/1992 and 1992/1993, the winters during which deep water formation was observed in the Aegean Sea, and also during the mid-1970s and the winters of 1963/1964 and 1968/1969. We find that the eNOTc cyclone state is anticorrelated with the North Atlantic Oscillation (NAO) prior to 1977/1978. After 1977/1978, the cNOTe state is anticorrelated with both the NAO and the North Caspian Pattern (NCP), showing that the area of influence of large scale atmospheric teleconnections on regional cyclone activity shifted from the eastern to the central Mediterranean during the late 1970s. A trend toward more frequent occurrence of the positive phase of the NAO produced less frequent cNOTe states since the late 1970s, increasing the number of days with strong cooling of the Aegean Sea surface waters.

Effects of Aerosol on Atmospheric Dynamics and Hydrologic Processes During Boreal Spring and Summer

NASA Technical Reports Server (NTRS)

Lau, William K. M.; Kim, M. K.; Kim, K. M.; Chin, Mian

2005-01-01

Global and regional climate impacts of present-day aerosol loading during boreal spring are investigated using the NASA finite volume General Circulation Model (fvGCM). Three-dimensional distributions of loadings of five species of tropospheric aerosols, i.e., sulfate, black carbon, organic carbon, soil dust, and sea salt are prescribed from outputs of the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The aerosol loadings are used to calculate the extinction coefficient, single scattering albedo, and asymmetric factor at eleven spectral wavelengths in the radiative transfer code. We find that aerosol-radiative forcing during boreal spring excites a wavetrain-like pattern in tropospheric temperature and geopotential height that emanates from Northern Africa, through Eurasia, to northeastern Pacific. Associated with the teleconnection is strong surface cooling over regions with large aerosol loading, i.e., China, India, and Africa. Low-to-mid tropospheric heating due to shortwave absorption is found in regions with large loading of dust (Northern Africa, and central East Asia), and black carbon (South and East Asia). In addition pronounced surface cooling is found over the Caspian Sea and warming over Eurasian and northeastern Asia, where aerosol loadings are relatively low. These warming and cooling are components of teleconnection pattern produced primarily by atmospheric heating from absorbing aerosols, i.e., dust from North Africa and black carbon from South and East Asia. Effects of aerosols on atmospheric hydrologic cycle in the Asian monsoon region are also investigated. Results show that absorbing aerosols, i.e., black carbon and dust, induce large-scale upper-level heating anomaly over the Tibetan Plateau in April and May, ushering in an early onset of the Indian summer monsoon. Absorbing aerosols also enhance lower-level heating and anomalous ascent over northern India, intensifying the Indian monsoon. Overall, the aerosol-induced large-scale surface tempera- cooling leads to a reduction of monsoon rainfall over the East Asia continent, and adjacent oceanic regions.

Effects of Aerosol on Atmospheric Dynamics and Hydrologic Processes during Boreal Spring and Summer

NASA Technical Reports Server (NTRS)

Lau, William K. M.; Kim, M. K.; Chin, Mian; Kim, K. M.

2005-01-01

Global and regional climate impacts of present-day aerosol loading during boreal spring are investigated using the NASA finite volume General Circulation Model (fvGCM). Three-dimensional distributions of loadings of five species of tropospheric aerosols, i.e., sulfate, black carbon, organic carbon, soil dust, and sea salt are prescribed from outputs of the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). The aerosol loadings are used to calculate the extinction coefficient, single scattering albedo, and asymmetric factor at eleven spectral wavelengths in the radiative transfer code. We find that aerosol-radiative forcing during boreal spring excites a wavetrain-like pattern in tropospheric temperature and geopotential height that emanates from Northern Africa, through Eurasia, to northeastern Pacific. Associated with the teleconnection is strong surface cooling over regions with large aerosol loading, i.e., China, India, and Africa. Low-to-mid tropospheric heating due to shortwave absorption is found in regions with large loading of dust (Northern Africa, and central East Asia), and black carbon (South and East Asia). In addition pronounced surface cooling is found over the Caspian Sea and warming over Eurasian and northeastern Asia, where aerosol loadings are relatively low. These warming and cooling are components of teleconnection pattern produced primarily by atmospheric heating from absorbing aerosols, i.e., dust from North Africa and.black carbon from South and East Asia. Effects of aerosols on atmospheric hydrologic cycle in the Asian monsoon region are also investigated. Results show that absorbing aerosols, i.e., black carbon and dust, induce large-scale upper-level heating anomaly over the Tibetan Plateau in April and May, ushering in an early onset of the Indian summer monsoon. Absorbing aerosols also enhance lower-level heating and anomalous ascent over northern India, intensifying the Indian monsoon. Overall, the aerosol-induced large-scale surface temperature cooling leads to a reduction of monsoon rainfall over the East Asia continent, and adjacent oceanic regions.

The Caspian Sea Catchment influenced by Atlantic Teleconnections in CESM1.2.2 and Observations

NASA Astrophysics Data System (ADS)

Nandini, S. D.; Prange, M.; Schulz, M.

2017-12-01

The Caspian Sea (CS) is the world's largest inland sea and located within a closed (endorheic) drainage basin [ 37°-47N, 47°-54°E]. It has undergone dynamic variations (>3 m) during the past century with huge impacts on the economy, ecosystem and livelihood of coastal people. The origin of these variations as well as future changes are disputable. Here, we examine the impact of the major seasonal North Atlantic teleconnection patterns, the North Atlantic Oscillation (NAO) and the East Atlantic pattern (EA) on Caspian hydroclimate variability from 1850-2100 CE. Five Numerical experiments at different atmospheric grid resolutions (2° and 1°) and atmospheric model versions (CAM4 and CAM5) are carried out with the coupled Community Earth System Model (CESM1.2.2). Results reveal the 1° CESM1.2.2 CAM5 captures DJF NAO (46.5%) and EA (13.4%), agreeing well with observational data (1850-2000). The DJF NAO has a strong influence on the DJF temperature, rainfall and evaporation minus precipitation (E-P) over the Caspian sub-basins (Volga, Ural, Terek and Kura). Furthermore, 1° model climate projections (2020-2100 CE) are performed with different Representative Concentration Pathways (RCP4.5 and RCP8.5) to examine likely changes in the NAO and EA and their influence on the Caspian catchment. The NAO under the RCP4.5 and RCP8.5 scenarios remains the leading mode with the highest variance and influences E-P with increased precipitation over the Volga basin and increased evaporation over the Caspian Sea. The above canceling effects act on the hydroclimate variability in the Caspian sub-basins. Moreover, it is indicated that no substantial change is predicted in the CSL by the year 2100. Keywords: North Atlantic Oscillation (NAO), CESM1.2.2 resolutions, Evaporation minus Precipitation (E-P), RCP4.5, RCP8.5

First-principles study of crystal structure, elastic stiffness constants, piezoelectric constants, and spontaneous polarization of orthorhombic Pna21-M2O3 (M = Al, Ga, In, Sc, Y)

NASA Astrophysics Data System (ADS)

Shimada, Kazuhiro

2018-03-01

We perform first-principles calculations to investigate the crystal structure, elastic and piezoelectric properties, and spontaneous polarization of orthorhombic M2O3 (M = Al, Ga, In, Sc, Y) with Pna21 space group based on density functional theory. The lattice parameters, full elastic stiffness constants, piezoelectric stress and strain constants, and spontaneous polarization are successfully predicted. Comparison with available experimental and computational results indicates the validity of our computational results. Detailed analysis of the results clarifies the difference in the bonding character and the origin of the strong piezoelectric response and large spontaneous polarization.

Role of changed Indo-Pacific atmospheric circulation in the recent disconnect between the Indian summer monsoon and ENSO

NASA Astrophysics Data System (ADS)

Feba, F.; Ashok, K.; Ravichandran, M.

2018-04-01

We explore the decadal variability of teleconnection from tropical Pacific to the Indian summer monsoon rainfall (ISMR) using various observational and Reanalysis datasets for the period 1958-2008. In confirmation with the earlier findings, we find that the interannual correlations between the various SST indices of ENSO and ISMR have continued to weaken. Interestingly, we find that even the robust lead correlations of the tropical pacific warm-water-volume with ISMR have weakened since late 1970s. Our analysis suggests that there is a relative intensification of the cross-equatorial flow from the southern hemisphere into the equatorial Indian Ocean associated with ISMR due to strenghtening of Mascarene High. Further, a shift in the surface wind circulation associated with monsoon over the northern pacific since late 1970s has resulted in a strenghtened cyclonic seasonal circulation south-east of Japan. These changed circulation features are a shift from the known circulation-signatures that efficiently teleconnect El Niño forcing to South Asia. These recent changes effectively weakened the teleconnection of the El Niño to ISMR.

2-Methoxypyridine as a Thymidine Mimic in Watson-Crick Base Pairs of DNA and PNA: Synthesis, Thermal Stability, and NMR Structural Studies.

PubMed

Novosjolova, Irina; Kennedy, Scott D; Rozners, Eriks

2017-11-02

The development of nucleic acid base-pair analogues that use new modes of molecular recognition is important both for fundamental research and practical applications. The goal of this study was to evaluate 2-methoxypyridine as a cationic thymidine mimic in the A-T base pair. The hypothesis was that including protonation in the Watson-Crick base pairing scheme would enhance the thermal stability of the DNA double helix without compromising the sequence selectivity. DNA and peptide nucleic acid (PNA) sequences containing the new 2-methoxypyridine nucleobase (P) were synthesized and studied by using UV thermal melting and NMR spectroscopy. Introduction of P nucleobase caused a loss of thermal stability of ≈10 °C in DNA-DNA duplexes and ≈20 °C in PNA-DNA duplexes over a range of mildly acidic to neutral pH. Despite the decrease in thermal stability, the NMR structural studies showed that P-A formed the expected protonated base pair at pH 4.3. Our study demonstrates the feasibility of cationic unnatural base pairs; however, future optimization of such analogues will be required. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

In-situ restoration of one-stage partial nitritation-anammox process deteriorated by nitrate build-up via elevated substrate levels

PubMed Central

Wang, Xiaolong; Gao, Dawen

2016-01-01

The one-stage partial nitritation and anammox process (PN/A) has been a promising microbial process to remove ammonia from wastewater especially with low carbon/nitrogen ratio. The main breakdown was the deterioration caused by overgrowth of nitrite oxidizing bacteria (NOB) resulting effluent nitrate build-up in the PN/A process. This study presented an in-situ restoring strategy for suppressing NOB activity in a one-stage granular PN/A system deteriorated over 2 months, using elevated concentrations of substrates (ammonia and nitrite) under limited dissolved oxygen level. The results showed that the NOB activity was successfully suppressed after 56 days of restoration, and finally the ratio of produced nitrate/consumed ammonium was reduced from 36.8% to 7%. On day 66 the nitrogen removal rate obtained as 1.2 kg N/(m3·d). The high FA level (5–40 mg/L) and low dissolved oxygen (<0.13 mg/L) were responsible for NOB suppression. From quantitative PCR (qPCR) analysis, after this restoration, anammox bacteria had a widely growth, and AOB stay stable, but Nitrospira increase and Nitrobacter declined. High amount of NOB was still persistent in the granules, which was not easy to wash-out and threaten the deammonification performance. PMID:27881860

Pollution-Induced Community Tolerance To Diagnose Hazardous Chemicals in Multiple Contaminated Aquatic Systems.

PubMed

Rotter, Stefanie; Gunold, Roman; Mothes, Sibylle; Paschke, Albrecht; Brack, Werner; Altenburger, Rolf; Schmitt-Jansen, Mechthild

2015-08-18

Aquatic ecosystems are often contaminated with large numbers of chemicals, which cannot be sufficiently addressed by chemical target analyses. Effect-directed analysis (EDA) enables the identification of toxicants in complex contaminated environmental samples. This study suggests pollution-induced community tolerance (PICT) as a confirmation tool for EDA to identify contaminants which actually impact on local communities. The effects of three phytotoxic compounds local periphyton communities, cultivated at a reference (R-site) and a polluted site (P-site), were assessed to confirm the findings of a former EDA study on sediments. The sensitivities of R- and P-communities to prometryn, tributyltin (TBT) and N-phenyl-2-naphthylamine (PNA) were quantified in short-term toxicity tests and exposure concentrations were determined. Prometryn and PNA concentrations were significantly higher at the P-site, whereas TBT concentrations were in the same range at both sites. Periphyton communities differed in biomass, but algal class composition and diatom diversity were similar. Community tolerance of P-communities was significantly enhanced for prometryn, but not for PNA and TBT, confirming site-specific effects on local periphyton for prometryn only. Thus, PICT enables in situ effect confirmation of phytotoxic compounds at the community level and seems to be suitable to support confirmation and enhance ecological realism of EDA.

Inhibition of HIV Replication by Cyclic and Hairpin PNAs Targeting the HIV-1 TAR RNA Loop

PubMed Central

Upert, Gregory; Di Giorgio, Audrey; Upadhyay, Alok; Manvar, Dinesh; Pandey, Nootan; Pandey, Virendra N.; Patino, Nadia

2012-01-01

Human immunodeficiency virus-1 (HIV-1) replication and gene expression entails specific interaction of the viral protein Tat with its transactivation responsive element (TAR), to form a highly stable stem-bulge-loop structure. Previously, we described triphenylphosphonium (TPP) cation-based vectors that efficiently deliver nucleotide analogs (PNAs) into the cytoplasm of cells. In particular, we showed that the TPP conjugate of a linear 16-mer PNA targeting the apical stem-loop region of TAR impedes Tat-mediated transactivation of the HIV-1 LTR in vitro and also in cell culture systems. In this communication, we conjugated TPP to cyclic and hairpin PNAs targeting the loop region of HIV-1 TAR and evaluated their antiviral efficacy in a cell culture system. We found that TPP-cyclic PNAs containing only 8 residues, showed higher antiviral potency compared to hairpin PNAs of 12 or 16 residues. We further noted that the TPP-conjugates of the 8-mer cyclic PNA as well as the 16-mer linear PNA displayed similar antiviral efficacy. However, cyclic PNAs were shown to be highly specific to their target sequences. This communication emphasizes on the importance of small constrained cyclic PNAs over both linear and hairpin structures for targeting biologically relevant RNA hairpins. PMID:23029603

DNA G-Wire Formation Using an Artificial Peptide is Controlled by Protease Activity.

PubMed

Usui, Kenji; Okada, Arisa; Sakashita, Shungo; Shimooka, Masayuki; Tsuruoka, Takaaki; Nakano, Shu-Ichi; Miyoshi, Daisuke; Mashima, Tsukasa; Katahira, Masato; Hamada, Yoshio

2017-11-16

The development of a switching system for guanine nanowire (G-wire) formation by external signals is important for nanobiotechnological applications. Here, we demonstrate a DNA nanostructural switch (G-wire <--> particles) using a designed peptide and a protease. The peptide consists of a PNA sequence for inducing DNA to form DNA-PNA hybrid G-quadruplex structures, and a protease substrate sequence acting as a switching module that is dependent on the activity of a particular protease. Micro-scale analyses via TEM and AFM showed that G-rich DNA alone forms G-wires in the presence of Ca 2+ , and that the peptide disrupted this formation, resulting in the formation of particles. The addition of the protease and digestion of the peptide regenerated the G-wires. Macro-scale analyses by DLS, zeta potential, CD, and gel filtration were in agreement with the microscopic observations. These results imply that the secondary structure change (DNA G-quadruplex <--> DNA/PNA hybrid structure) induces a change in the well-formed nanostructure (G-wire <--> particles). Our findings demonstrate a control system for forming DNA G-wire structures dependent on protease activity using designed peptides. Such systems hold promise for regulating the formation of nanowire for various applications, including electronic circuits for use in nanobiotechnologies.

Soil aggregate stratification of nematodes and ammonia oxidizers affects nitrification in an acid soil.

PubMed

Jiang, Yuji; Jin, Chen; Sun, Bo

2014-10-01

Nitrification plays a central role in global nitrogen cycle, which is affected by interaction between soil microfauna and microorganisms. The impact of synchronized changes in nematodes and ammonia oxidizers within aggregate fractions on nitrification was investigated in an acid soil under 10-year manure application. Nematodes, ammonia oxidizers and potential nitrification activity (PNA) were examined in three soil aggregate fractions under four fertilization regimes. Pyrosequencing data revealed that the dominant bacterial amoA operational taxonomic units (OTUs) were related to Nitrosospira species, while archaeal OTUs were affiliated with Nitrososphaera and Nitrosotalea species. PNA was more strongly correlated with ammonia-oxidizing bacteria (AOB) abundance than ammonia-oxidizing archaea (AOA) abundance, although AOA were dominant in the acid soil. Plant parasites had a negative effect on AOB abundance; however, bacterivores stimulated AOB abundance and contributed more to PNA than plant parasites. Aggregate fractions exerted significant impacts on AOA abundance and AOB community composition. Total carbon content strongly affected the abundance and composition of AOA community, while soil pH primarily affected that of AOB community. Soil variables explained 62.7% and 58.1% variations, and nematode variables explained 11.7% and 19.5% variations in the AOA and AOB community composition respectively. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

The impact of boreal autumn SST anomalies over the South Pacific on boreal winter precipitation over East Asia

NASA Astrophysics Data System (ADS)

Ao, Juan; Sun, Jianqi

2016-05-01

The possible mechanism behind the variability in the dipole pattern of boreal winter precipitation over East Asia is analyzed in this study. The results show that the SST anomalies (SSTAs) over the South Pacific Ocean (SPO) in boreal autumn are closely related to the variability in the dipole pattern of boreal winter precipitation over East Asia. The physical link between the boreal autumn SPO SSTAs and the boreal winter East Asian precipitation dipole pattern is shown to mainly be the seasonal persistence of the SPO SSTAs themselves. The seasonal persistence of the SPO SSTAs can memorize and transport the signal of the boreal autumn SSTAs to the following winter, and then stimulates a meridional teleconnection pattern from the SH to the NH, resulting in a meridional dipole pattern of atmospheric circulation over East Asia in boreal winter. As a major influencing factor, this dipole pattern of the atmospheric circulation can finally lead to the anomalous precipitation dipole pattern over East Asia in boreal winter. These observed physical processes are further confirmed in this study through numerical simulation. The evidence from this study, showing the impact of the SPO SSTAs in boreal autumn, not only deepens our understanding of the variability in East Asian boreal winter precipitation, but also provides a potentially useful predictor for precipitation in the region.

The efficacy of hypotonic and near-isotonic saline for parenteral fluid therapy given at low maintenance rate in preventing significant change in plasma sodium in post-operative pediatric patients: protocol for a prospective randomized non-blinded study

PubMed Central

2011-01-01

Background Hyponatremia is the most frequent electrolyte abnormality observed in post-operative pediatric patients receiving intravenous maintenance fluid therapy. If plasma sodium concentration (p-Na+) declines to levels below 125 mmol/L in < 48 h, transient or permanent brain damage may occur. There is an intense debate as to whether the administered volume (full rate vs. restricted rate of infusion) and the composition of solutions used for parenteral maintenance fluid therapy (hypotonic vs. isotonic solutions) contribute to the development of hyponatremia. So far, there is no definitive pediatric data to support a particular choice of parenteral fluid for maintenance therapy in post-surgical patients. Methods/Design Our prospective randomized non-blinded study will be conducted in healthy children and adolescents aged 1 to 14 years who have been operated for acute appendicitis. Patients will be randomized either to intravenous hypotonic (0.23% or 0.40% sodium chloride in glucose, respectively) or near-isotonic (0.81% sodium chloride in glucose) solution given at approximately three-fourths of the average maintenance rate. The main outcome of interest from this study is to evaluate 24 h post-operatively whether differences in p-Na+ between treatment groups are large enough to be of clinical relevance. In addition, water and electrolyte balance as well as regulatory hormones will be measured. Discussion This study will provide valuable information on the efficacy of hypotonic and near-isotonic fluid therapy in preventing a significant decrease in p-Na+. Finally, by means of careful electrolyte and water balance and by measuring regulatory hormones our results will also contribute to a better understanding of the physiopathology of post-operative changes in p-Na+ in a population at risk for hyponatremia. Trial registration The protocol for this study is registered with the current controlled trials registry; registry number: ISRCTN43896775. PMID:21729308

Cluster analysis of multiple planetary flow regimes

NASA Technical Reports Server (NTRS)

Mo, Kingtse; Ghil, Michael

1987-01-01

A modified cluster analysis method was developed to identify spatial patterns of planetary flow regimes, and to study transitions between them. This method was applied first to a simple deterministic model and second to Northern Hemisphere (NH) 500 mb data. The dynamical model is governed by the fully-nonlinear, equivalent-barotropic vorticity equation on the sphere. Clusters of point in the model's phase space are associated with either a few persistent or with many transient events. Two stationary clusters have patterns similar to unstable stationary model solutions, zonal, or blocked. Transient clusters of wave trains serve as way stations between the stationary ones. For the NH data, cluster analysis was performed in the subspace of the first seven empirical orthogonal functions (EOFs). Stationary clusters are found in the low-frequency band of more than 10 days, and transient clusters in the bandpass frequency window between 2.5 and 6 days. In the low-frequency band three pairs of clusters determine, respectively, EOFs 1, 2, and 3. They exhibit well-known regional features, such as blocking, the Pacific/North American (PNA) pattern and wave trains. Both model and low-pass data show strong bimodality. Clusters in the bandpass window show wave-train patterns in the two jet exit regions. They are related, as in the model, to transitions between stationary clusters.

The spatiotemporal changes in precipitation extremes over Canada and their connections to large-scale climate patterns

NASA Astrophysics Data System (ADS)

Yang, Y.; Gan, T. Y.; Tan, X.

2017-12-01

In the past few decades, there have been more extreme climate events around the world, and Canada has also suffered from numerous extreme precipitation events. In this paper, trend analysis, change point analysis, probability distribution function, principal component analysis and wavelet analysis were used to investigate the spatial and temporal patterns of extreme precipitation in Canada. Ten extreme precipitation indices were calculated using long-term daily precipitation data from 164 gauging stations. Several large-scale climate patterns such as El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Pacific-North American (PNA), and North Atlantic Oscillation (NAO) were selected to analyze the relationships between extreme precipitation and climate indices. Convective Available Potential Energy (CAPE), specific humidity, and surface temperature were employed to investigate the potential causes of the trends.The results show statistically significant positive trends for most indices, which indicate increasing extreme precipitation. The majority of indices display more increasing trends along the southern border of Canada while decreasing trends dominate in the central Canadian Prairies (CP). In addition, strong connections are found between the extreme precipitation and climate indices and the effects of climate pattern differ for each region. The seasonal CAPE, specific humidity, and temperature are found to be closely related to Canadian extreme precipitation.

Spatial-temporal variations of dominant drought/flood modes and the associated atmospheric circulation and ocean events in rainy season over the east of China

NASA Astrophysics Data System (ADS)

Huang, Shaoni; Huang, Fei

2012-06-01

By using Season-reliant Empirical Orthogonal Function (S-EOF) analysis, three dominant modes of the spatial-temporal evolution of the drought/flood patterns in the rainy season over the east of China are revealed for the period of 1960-2004. The first two leading modes occur during the turnabout phase of El Niño-Southern Oscillation (ENSO) decaying year, but the drought/flood patterns in the rainy season over the east of China are different due to the role of the Indian Ocean (IO). The first leading mode appears closely correlated with the ENSO events. In the decaying year of El Niño, the associated western North Pacific (WNP) anticyclone located over the Philippine Sea persists from the previous winter to the next early summer, transports warm and moist air toward the southern Yangtze River in China, and leads to wet conditions over this entire region. Therefore, the precipitation anomaly in summer exhibits a `Southern Flood and Northern Drought' pattern over East China. On the other hand, the basin-wide Indian Ocean sea surface temperature anomaly (SSTA) plays a crucial role in prolonging the impact of ENSO on the second mode during the ENSO decaying summer. The Indian Ocean basin mode (IOBM) warming persists through summer and unleashes its influence, which forces a Matsuno-Gill pattern in the upper troposphere. Over the subtropical western North Pacific, an anomalous anticyclone forms in the lower troposphere. The southerlies on the northwest flank of this anticyclone increase the moisture transport onto central China, leading to abundant rainfall over the middle and lower reaches of the Yangtze River and Huaihe River valleys. The anomalous anticyclone causes dry conditions over South China and the South China Sea (SCS). The precipitation anomaly in summer exhibits a `Northern Flood and Southern Drought' pattern over East China. Therefore, besides the ENSO event the IOBM is an important factor to influence the drought/flood patterns in the rainy season over the east of China. The third mode is positively correlated with the tropical SSTA in the Indian Ocean from the spring of preceding year(-1) to the winter of following year(+1), but not related to the ENSO events. The positive SSTA in the South China Sea and the Philippine Sea persists from spring to autumn, leading to weak north-south and land-sea thermal contrasts, which may weaken the intensity of the East Asia summer monsoon. The weakened rainfall over the northern Indian monsoon region may link to the third spatial mode through the `Silk Road' teleconnection or a part of circumglobal teleconnection (CGT). The physical mechanisms that reveal these linkages remain elusive and invite further investigation.

Nano metal-organic framework (NMOF)-based strategies for multiplexed microRNA detection in solution and living cancer cells

NASA Astrophysics Data System (ADS)

Wu, Yafeng; Han, Jianyu; Xue, Peng; Xu, Rong; Kang, Yuejun

2015-01-01

MiRNAs are an emerging type of biomarker for diagnostics and prognostics. A reliable sensing strategy that can monitor miRNA expression in living cancer cells would be critical in view of its extensive advantages for fundamental research related to miRNA-associated bioprocesses and biomedical applications. Conventional miRNA sensing methods include northern blot, microarrays and real-time quantitative PCR. However, none of them is able to monitor miRNA levels expressed in living cancer cells in a real-time fashion. Some fluorescennt biosensors developed recently from carbon nanomaterials, such as single-walled carbon nanotubes (SWNTs), graphene oxide (GO), and carbon nanoparticles, have been successfully used for assaying miRNA in vitro; however the preparation processes are often expensive, complicated and time-consuming, which have motivated the research on other substitute and novel materials. Herein we present a novel sensing strategy based on peptide nucleic acid (PNA) probes labeled with fluorophores and conjugated with an NMOF vehicle to monitor multiplexed miRNAs in living cancer cells. The NMOF works as a fluorescence quencher of the labelled PNA that is firmly bound with the metal center. In the presence of a target miRNA, PNA is hybridized and released from the NMOF leading to the recovery of fluorescence. This miRNA sensor not only enables the quantitative and highly specific detection of multiplexed miRNAs in living cancer cells, but it also allows the precise and in situ monitoring of the spatiotemporal changes of miRNA expression.MiRNAs are an emerging type of biomarker for diagnostics and prognostics. A reliable sensing strategy that can monitor miRNA expression in living cancer cells would be critical in view of its extensive advantages for fundamental research related to miRNA-associated bioprocesses and biomedical applications. Conventional miRNA sensing methods include northern blot, microarrays and real-time quantitative PCR. However, none of them is able to monitor miRNA levels expressed in living cancer cells in a real-time fashion. Some fluorescennt biosensors developed recently from carbon nanomaterials, such as single-walled carbon nanotubes (SWNTs), graphene oxide (GO), and carbon nanoparticles, have been successfully used for assaying miRNA in vitro; however the preparation processes are often expensive, complicated and time-consuming, which have motivated the research on other substitute and novel materials. Herein we present a novel sensing strategy based on peptide nucleic acid (PNA) probes labeled with fluorophores and conjugated with an NMOF vehicle to monitor multiplexed miRNAs in living cancer cells. The NMOF works as a fluorescence quencher of the labelled PNA that is firmly bound with the metal center. In the presence of a target miRNA, PNA is hybridized and released from the NMOF leading to the recovery of fluorescence. This miRNA sensor not only enables the quantitative and highly specific detection of multiplexed miRNAs in living cancer cells, but it also allows the precise and in situ monitoring of the spatiotemporal changes of miRNA expression. Electronic supplementary information (ESI) available: Extra figures and tables. See DOI: 10.1039/c4nr05447d

Interannual Variability, Global Teleconnection, and Potential Predictability Associated with the Asian Summer Monsoon

NASA Technical Reports Server (NTRS)

Lau, K. M.; Kim, K. M.; Li, J. Y.

2001-01-01

In this Chapter, aspects of global teleconnections associated with the interannual variability of the Asian summer monsoon (ASM) are discussed. The basic differences in the basic dynamics of the South Asian Monsoon and the East Asian monsoon, and their implications on global linkages are discussed. Two teleconnection modes linking ASM variability to summertime precipitation over the continental North America were identified. These modes link regional circulation and precipitation anomalies over East Asia and continental North America, via coupled atmosphere-ocean variations over the North Pacific. The first mode has a large zonally symmetrical component and appears to be associated with subtropical jetstream variability and the second mode with Rossby wave dispersion. Both modes possess strong sea surface temperature (SST) expressions in the North Pacific. Results show that the two teleconnection modes may have its origin in intrinsic modes of sea surface temperature variability in the extratropical oceans, which are forced in part by atmospheric variability and in part by air-sea interaction. The potential predictability of the ASM associated with SST variability in different ocean basins is explored using a new canonical ensemble correlation prediction scheme. It is found that SST anomalies in tropical Pacific, i.e., El Nino, is the most dominant forcing for the ASM, especially over the maritime continent and eastern Australia. SST anomalies in the India Ocean may trump the influence from El Nino in western Australia and western maritime continent. Both El Nino, and North Pacific SSTs contribute to monsoon precipitation anomalies over Japan, southern Korea, northern and central China. By optimizing SST variability signals from the world ocean basins using CEC, the overall predictability of ASM can be substantially improved.

Quantitative Estimation of the Impact of European Teleconnections on Interannual Variation of East Asian Winter Temperature and Monsoon

NASA Technical Reports Server (NTRS)

Lim, Young-Kwon; Kim, Hae-Dong

2014-01-01

The impact of European teleconnections including the East AtlanticWest Russia (EA-WR), the Scandinavia (SCA), and the East Atlantic (EA) on East Asian winter temperature variability was quantified and compared with the combined effect of the Arctic Oscillation (AO), the Western Pacific (WP), and the El-Nino Southern Oscillation (ENSO), which are originated in the Northern Hemispheric high-latitudes or the Pacific. Three European teleconnections explained 22-25 percent of the total monthly upper-tropospheric height variance over Eurasia. Regression analysis revealed warming by EA-WR and EA and cooling by SCA over mid-latitude East Asia during their positive phase and vice versa. Temperature anomalies were largely explained by the advective temperature change process at the lower troposphere. The average spatial correlation over East Asia (90-180E, 10-80N) for the last 34 winters between observed and reconstructed temperature comprised of AO, WP and ENSO effect (AWE) was approximately 0.55, and adding the European teleconnection components (ESE) to the reconstructed temperature improved the correlation up to approximately 0.64. Lower level atmospheric structure demonstrated that approximately five of the last 34 winters were significantly better explained by ESE than AWE to determine East Asian seasonal winter temperatures. We also compared the impact between EA-WR and AO on the 1) East Asian winter monsoon, 2) cold surge, and 3) the Siberian high. These three were strongly coupled, and their spatial features and interannual variation were somewhat better explained by EA-WR than AO. Results suggest that the EA-WR impact must be treated more importantly than previously thought for a better understanding of East Asian winter temperature and monsoon variability.

The IOD-ENSO precursory teleconnection over the tropical Indo-Pacific Ocean: dynamics and long-term trends under global warming

NASA Astrophysics Data System (ADS)

Yuan, Dongliang; Hu, Xiaoyue; Xu, Peng; Zhao, Xia; Masumoto, Yukio; Han, Weiqing

2018-01-01

The dynamics of the teleconnection between the Indian Ocean Dipole (IOD) in the tropical Indian Ocean and El Niño-Southern Oscillation (ENSO) in the tropical Pacific Ocean at the time lag of one year are investigated using lag correlations between the oceanic anomalies in the southeastern tropical Indian Ocean in fall and those in the tropical Indo-Pacific Ocean in the following winter-fall seasons in the observations and in high-resolution global ocean model simulations. The lag correlations suggest that the IOD-forced interannual transport anomalies of the Indonesian Throughflow generate thermocline anomalies in the western equatorial Pacific Ocean, which propagate to the east to induce ocean-atmosphere coupled evolution leading to ENSO. In comparison, lag correlations between the surface zonal wind anomalies over the western equatorial Pacific in fall and the Indo-Pacific oceanic anomalies at time lags longer than a season are all insignificant, suggesting the short memory of the atmospheric bridge. A linear continuously stratified model is used to investigate the dynamics of the oceanic connection between the tropical Indian and Pacific Oceans. The experiments suggest that interannual equatorial Kelvin waves from the Indian Ocean propagate into the equatorial Pacific Ocean through the Makassar Strait and the eastern Indonesian seas with a penetration rate of about 10%-15% depending on the baroclinic modes. The IOD-ENSO teleconnection is found to get stronger in the past century or so. Diagnoses of the CMIP5 model simulations suggest that the increased teleconnection is associated with decreased Indonesian Throughflow transports in the recent century, which is found sensitive to the global warming forcing.

Supramolecular nanofiber of pyrene-lactose conjugates and its two-photon fluorescence imaging.

PubMed

Sun, Qian; Zhu, Hong-Yu; Wang, Jun-Fang; Chen, Xiao; Wang, Ke-Rang; Li, Xiao-Liu

2018-04-23

A lactose modified pyrene derivative (Py-Lac) was synthesized, with which novel twisted supramolecular nanofibers in diameter about 20 nm were constructed by self-assembly. The nanofibers showed solid-state fluorescence between 400 nm and 650 nm with the maximum emission at 495 nm. Furthermore, its recognition reaction with PNA lectin was investigated by fluorescence spectra and turbidity assays. It is interesting found that the supramolecular assembly as multivalent glycocluster exhibited unique and selectively binding interactions with PNA lectin with the binding constant of 5.74 × 10 6  M -1 . Moreover, compound Py-Lac showed two-photon fluorescence imaging with Hep G2 cells. Copyright © 2018 Elsevier Inc. All rights reserved.

Ionizing radiation in the field of hydrogels used for agriculture and medicine

NASA Astrophysics Data System (ADS)

Radoiu, M.; Martin, D.; Oproiu, C.; Toma, M.; Popescu, A. S.; Bestea, V.; Dragusin, M.; Moraru, R.; Calinescu, I.; Manea, A.

1999-01-01

Some hydrogel types, obtained by gamma ray and electron beam irradiation, such as homopolymers of acrylamide (pAA type), co-polymers of acrylamide and sodium acrylate (pAANA type), homo-polymers of sodium acrylate (pNA type) and homo-polymers of 2-hydroxyethylmethacrylate (pHEMA type), are presented. The effects of the solution's chemical composition, swelling medium nature, radiation absorbed dose and radiation absorbed dose rate upon the swelling degree and mechanical strength of pAA, pAANA, pNA types are discussed. For the pHEMA type, which are reinforced in the polyester network, the studies concerning the influence of the irradiation parameters and chemical composition upon the shape stability after swelling and surface's roughness are also discussed.

The relative contributions of tropical Pacific sea surface temperatures and atmospheric internal variability to the recent global warming hiatus

NASA Astrophysics Data System (ADS)

Deser, Clara; Guo, Ruixia; Lehner, Flavio

2017-08-01

The recent slowdown in global mean surface temperature (GMST) warming during boreal winter is examined from a regional perspective using 10-member initial-condition ensembles with two global coupled climate models in which observed tropical Pacific sea surface temperature anomalies (TPAC SSTAs) and radiative forcings are specified. Both models show considerable diversity in their surface air temperature (SAT) trend patterns across the members, attesting to the importance of internal variability beyond the tropical Pacific that is superimposed upon the response to TPAC SSTA and radiative forcing. Only one model shows a close relationship between the realism of its simulated GMST trends and SAT trend patterns. In this model, Eurasian cooling plays a dominant role in determining the GMST trend amplitude, just as in nature. In the most realistic member, intrinsic atmospheric dynamics and teleconnections forced by TPAC SSTA cause cooling over Eurasia (and North America), and contribute equally to its GMST trend.

Arctic and Tropical Influence on Extreme Precipitation Events, Atmospheric Rivers, and Associated Isotopic Values in the Western U.S.

NASA Astrophysics Data System (ADS)

McCabe-Glynn, S. E.; Johnson, K. R.; Zou, Y.; Welker, J. M.; Strong, C.; Rutz, J. J.; Yu, J. Y.; Yoshimura, K.; Sellars, S. L.; Payne, A. E.

2014-12-01

Extreme precipitation events along the U.S. West Coast can result in major damage and are projected by most climate models to increase in frequency and severity. One of the most prevalent extreme precipitation events that occurs along the west coast of North America are known as 'Atmospheric Rivers' (ARs), whereby extensive fluxes of water vapor are transported from the tropics and/or subtropics, delivering substantial precipitation and contributing to flooding when they encounter mountains. This region is particularly vulnerable to ARs, with 30-50% of annual precipitation in this region occurring from just a few AR events. Because of the tropical and/or subtropical origin of ARs, they can carry unique isotopic properties. Here we present the results of analysis of weekly precipitation data and accompanying isotopic values from Giant Forest, in Sequoia National Park, in the southwestern Sierra Nevada Mountains (36.57° N; 118.78° W; 1921m) from 2001 to 2011. To better characterize these events, we focused on the 10 weeks with the highest precipitation totals (all greater than 150 mm) during the study period. We show that nine of the top ten weeks contain documented 'AR' events and that 90% occurred during the negative phase of the Arctic Oscillation. A comparison of extreme precipitation events across the Western U.S. with several key climate indices demonstrate these events occur most frequently when the negative phase of the Arctic Oscillation is in sync with the negative phase of the El Niño Southern Oscillation (ENSO) and the negative or neutral Pacific North American (PNA) pattern. We also demonstrate that central or eastern Pacific location of ENSO sea surface temperature anomalies can further enhance predictive capabilities of the landfall location of extreme precipitation. Stable isotope results show that extreme precipitation events are characterized by highly variable δ18O (-7.20‰ to -19.27‰), however, we find that more negative δ18O values typically occur during the negative PNA pattern. Finally, we will present the results of data comparison with NCAR-NCEP reanalysis, Hysplit back trajectories, and isotope enabled climate model (IsoGSM) results.

Multi-scale Quantitative Precipitation Forecasting Using ...

EPA Pesticide Factsheets

Global sea surface temperature (SST) anomalies can affect terrestrial precipitation via ocean-atmosphere interaction known as climate teleconnection. Non-stationary and non-linear characteristics of the ocean-atmosphere system make the identification of the teleconnection signals difficult to be detected at a local scale as it could cause large uncertainties when using linear correlation analysis only. This paper explores the relationship between global SST and terrestrial precipitation with respect to long-term non-stationary teleconnection signals during 1981-2010 over three regions in North America and one in Central America. Empirical mode decomposition as well as wavelet analysis is utilized to extract the intrinsic trend and the dominant oscillation of the SST and precipitation time series in sequence. After finding possible associations between the dominant oscillation of seasonal precipitation and global SST through lagged correlation analysis, the statistically significant SST regions are extracted based on the correlation coefficient. With these characterized associations, individual contribution of these SST forcing regions linked to the related precipitation responses are further quantified through nonlinear modeling with the aid of extreme learning machine. Results indicate that the non-leading SST regions also contribute a salient portion to the terrestrial precipitation variability compared to some known leading SST regions. In some cases, these

A binary genetic programing model for teleconnection identification between global sea surface temperature and local maximum monthly rainfall events

NASA Astrophysics Data System (ADS)

Danandeh Mehr, Ali; Nourani, Vahid; Hrnjica, Bahrudin; Molajou, Amir

2017-12-01

The effectiveness of genetic programming (GP) for solving regression problems in hydrology has been recognized in recent studies. However, its capability to solve classification problems has not been sufficiently explored so far. This study develops and applies a novel classification-forecasting model, namely Binary GP (BGP), for teleconnection studies between sea surface temperature (SST) variations and maximum monthly rainfall (MMR) events. The BGP integrates certain types of data pre-processing and post-processing methods with conventional GP engine to enhance its ability to solve both regression and classification problems simultaneously. The model was trained and tested using SST series of Black Sea, Mediterranean Sea, and Red Sea as potential predictors as well as classified MMR events at two locations in Iran as predictand. Skill of the model was measured in regard to different rainfall thresholds and SST lags and compared to that of the hybrid decision tree-association rule (DTAR) model available in the literature. The results indicated that the proposed model can identify potential teleconnection signals of surrounding seas beneficial to long-term forecasting of the occurrence of the classified MMR events.

Global Water Cycle Diagrams Minimize Human Influence and Over-represent Water Security

NASA Astrophysics Data System (ADS)

Abbott, B. W.; Bishop, K.; Zarnetske, J. P.; Minaudo, C.; Chapin, F. S., III; Plont, S.; Marçais, J.; Ellison, D.; Roy Chowdhury, S.; Kolbe, T.; Ursache, O.; Hampton, T. B.; GU, S.; Chapin, M.; Krause, S.; Henderson, K. D.; Hannah, D. M.; Pinay, G.

2017-12-01

The diagram of the global water cycle is the central icon of hydrology, and for many people, the point of entry to thinking about key scientific concepts such as conservation of mass, teleconnections, and human dependence on ecological systems. Because humans now dominate critical components of the hydrosphere, improving our understanding of the global water cycle has graduated from an academic exercise to an urgent priority. To assess how the water cycle is conceptualized by researchers and the general public, we analyzed 455 water cycle diagrams from textbooks, scientific articles, and online image searches performed in different languages. Only 15% of diagrams integrated human activity into the water cycle and 77% showed no sign of humans whatsoever, although representation of humans varied substantially by region (lowest in China, N. America, and Australia; highest in Western Europe). The abundance and accessibility of freshwater resources were overrepresented, with 98% of diagrams omitting water pollution and climate change, and over 90% of diagrams making no distinction for saline groundwater and lakes. Oceanic aspects of the water cycle (i.e. ocean size, circulation, and precipitation) and related teleconnections were nearly always underrepresented. These patterns held across disciplinary boundaries and through time. We explore the historical and contemporary reasons for some of these biases and present a revised version of the global water cycle based on research from natural and social sciences. We conclude that current depictions of the global water cycle convey a false sense of water security and that reintegrating humans into water cycle diagrams is an important first step towards understanding and sustaining the hydrosocial cycle.

The response of European and Asian climate to global and regional aerosol emissions

NASA Astrophysics Data System (ADS)

Wilcox, Laura; Dunstone, Nick; Highwood, Eleanor; Bollasina, Massimo; Dong, Buwen; Sutton, Rowan

2017-04-01

Asia has the world's highest anthropogenic aerosol loading and has experienced a dramatic increase in emissions since the 1950s, which has continued in the 21st century, in stark contrast with European (and North American) emissions which started to decrease in the 1970s. We use a set of transient coupled model experiments (HadGEM2-GC2) to explore the regional climate effects of anthropogenic aerosol changes since the 1980s, with a focus on the European and Asian responses. Comparing simulations with globally varying aerosol emissions to an equivalent set with Asian emissions fixed at their 1971-1980 mean over Asia, we identify the contribution of Asian emissions to the total impact. Identifying thermodynamic and dynamic responses to global and regional aerosol changes, we diagnose atmospheric teleconnections and their interactions with local processes, and the mechanisms by which aerosol affects both European and Asian climate. It is found that Asian aerosols led to substantial changes in Asian climate, weakening the summer monsoon, which is a key driver of the observed precipitation changes there in recent decades. Asian emissions are also able to induce planetary-scale teleconnection patterns in both winter and summer. The impact of the regional diabatic heating anomaly propagates remotely by exciting northern hemisphere wave-trains which, enhanced by regional feedbacks, cause changes in near-surface climate over Europe. To examine the robustness of the mechanisms we identify in HadGEM2, we analyse similar sets of experiments from NorESM1-M and GFDL-CM3: models with very different climatologies and representations of aerosol processes.

Client-Friendly Forecasting: Seasonal Runoff Predictions Using Out-of-the-Box Indices

NASA Astrophysics Data System (ADS)

Weil, P.

2013-12-01

For more than a century, statistical relationships have been recognized between atmospheric conditions at locations separated by thousands of miles, referred to as teleconnections. Some of the recognized teleconnections provide useful information about expected hydrologic conditions, so certain records of atmospheric conditions are quantified and published as hydroclimate indices. Certain hydroclimate indices can serve as strong leading indicators of climate patterns over North America and can be used to make skillful forecasts of seasonal runoff. The methodology described here creates a simple-to-use model that utilizes easily accessed data to make forecasts of April through September runoff months before the runoff season begins. For this project, forecasting models were developed for two snowmelt-driven river systems in Colorado and Wyoming. In addition to the global hydroclimate indices, the methodology uses several local hydrologic variables including the previous year's drought severity, headwater snow water equivalent and the reservoir contents for the major reservoirs in each basin. To improve the skill of the forecasts, logistic regression is used to develop a model that provides the likelihood that a year will fall into the upper, middle or lower tercile of historical flows. Categorical forecasting has two major advantages over modeling of specific flow amounts: (1) with less prediction outcomes models tend to have better predictive skill and (2) categorical models are very useful to clients and agencies with specific flow thresholds that dictate major changes in water resources management. The resulting methodology and functional forecasting model product is highly portable, applicable to many major river systems and easily explained to a non-technical audience.

Drivers and Effects of Virtual Water Cycling

NASA Astrophysics Data System (ADS)

D'Odorico, P.

2016-12-01

The increasing global demand for farmland products by the growing and increasingly burgeoning human population is placing unprecedented pressure on the global agricultural system and its water resources. Many regions of the world that are not self-sufficient because of their chronic water scarcity or lack of suitable agricultural land strongly depend on the importation of agricultural commodities and associated embodied (or "virtual") water. International trade, however, may become unreliable when the supplies in the international food market are scarce. As a result, transboundary investments in agricultural land have become a priority for a number of governments and corporations that are trying to expand their agricultural production while securing good profits. This global "land rush" is often driven by the need for a secure access to water resources for agriculture. The globalization of water and land through trade and foreign land acquisitions is leading to a displacement of land use and a disconnection between human populations and the water resources they rely on. Despite the recognized importance of these phenomena in reshaping the patterns of water dependency through teleconnections between consumer behavior and production areas, their effect on global and regional food security, remains poorly quantified. New teleconnections are also emerging from the increasing water use for energy production. Competition in water use for food and energy security constitutes the core of an emerging debate that is generating new questions on the environmental, ethical, economic, and policy implications of human appropriation of water resources. This lecture will examine the ways societies virtually modify their access to water through trade and foreign land acquisitions to meet their growing food and energy needs.

Structured teleconnections reveal the South American monsoon onset: A network approach

NASA Astrophysics Data System (ADS)

Ciemer, Catrin; Ekhtiari, Nikoo; Barbosa, Henrique; Boers, Niklas; Donner, Reik; Kurths, Jürgen; Rammig, Anja; Winkelmann, Ricarda

2017-04-01

The regional onset dates of the global monsoon systems are, to first order, determined by the seasonal shift of the intertropical convergence zone. However, precise onset dates vary substantially from year to year due to the complexity of the involved mechanisms. In this study, we investigate processes determining the onset of the South American monsoon system (SAMS). In recent years, a trend towards later onset dates of the SAMS has been observed. A later onset of the monsoon can have severe impacts on agriculture and infrastructure such as farming, water transport routes, and the stability of the Amazon rainforest in the long term. Possible reasons for this shift involve a multitude of climatic phenomena and variables relevant for the SAMS. To account for the highly interactive nature of the SAMS, we here investigate it with the help of complex networks. By studying the temporal changes of the correlation structure in spatial rainfall networks, we are able to determine coherent areas of similar precipitation patterns, spot teleconnections in terms of strongly correlated areas, detect key regions for precipitation correlations, and finally reveal the monsoon onset by an abrupt shift from an unordered to an ordered correlation structure of the network. To further evaluate the shift in the monsoon onset, we couple our rainfall network to a network of climate networks using sea surface temperature as a second variable. We are thereby able to emphasize oceanic regions that are particularly important for the SAMS and anticipate the influence of future changes of sea-surface temperature on the SAMS.

Spatiotemporal dynamics of historical droughts over Canada: role of observational uncertainties and teleconnections

NASA Astrophysics Data System (ADS)

Asong, Z. E.; Wheater, H. S.; Bonsal, B. R.; Razavi, S.; Kurkute, S.

2017-12-01

Drought is a naturally occurring environmental phenomenon, and a major costly natural hazard that can have devastating impacts on regional water resources, agriculture, energy and other social-ecological systems. Of particular interest here is drought occurrence over Canada, where drought is both a frequent and damaging phenomenon, particularly in the interior Prairie region. However, nation-wide drought assessments are currently lacking and hampered partly by observational uncertainties. Therefore, this study aims to fill these gaps by providing a comprehensive analysis of historical droughts over the whole of Canada, including the role of observational uncertainties and teleconnectivity. This is carried out by analysing different monthly precipitation and temperature products for the period 1950 - 2013. Drought events are characterized by the Standardized Precipitation-Evapotranspiration Index (SPEI) over various temporal scales (1, 3, 6, and 12 consecutive months and 6 months from April to September and 12 months from October to September). First, trends in the SPEI are investigated by means of the Modified Mann Kendall test, while the Pettitt test was used to detect change points/transition years during the period of record. Major spatial patterns of long-term change, inter/intra-annual variability and periodicity of drought events are then characterized using the Rotated Empirical Orthogonal Function, and Continuous Wavelet Transform techniques. In addition, potential key drivers of drought are investigated using Wavelet Coherence Analysis, with a special emphasis on the role played by large-scale modes of climate variability. This provides important insight into the physical and dynamical mechanisms associated with the variability of drought events over different Canadian sub-regions.

Climate Teleconnections and Recent Patterns of Human and Animal Disease Outbreaks

PubMed Central

Anyamba, Assaf; Linthicum, Kenneth J.; Small, Jennifer L.; Collins, Kathrine M.; Tucker, Compton J.; Pak, Edwin W.; Britch, Seth C.; Eastman, James Ronald; Pinzon, Jorge E.; Russell, Kevin L.

2012-01-01

Background Recent clusters of outbreaks of mosquito-borne diseases (Rift Valley fever and chikungunya) in Africa and parts of the Indian Ocean islands illustrate how interannual climate variability influences the changing risk patterns of disease outbreaks. Although Rift Valley fever outbreaks have been known to follow periods of above-normal rainfall, the timing of the outbreak events has largely been unknown. Similarly, there is inadequate knowledge on climate drivers of chikungunya outbreaks. We analyze a variety of climate and satellite-derived vegetation measurements to explain the coupling between patterns of climate variability and disease outbreaks of Rift Valley fever and chikungunya. Methods and Findings We derived a teleconnections map by correlating long-term monthly global precipitation data with the NINO3.4 sea surface temperature (SST) anomaly index. This map identifies regional hot-spots where rainfall variability may have an influence on the ecology of vector borne disease. Among the regions are Eastern and Southern Africa where outbreaks of chikungunya and Rift Valley fever occurred 2004–2009. Chikungunya and Rift Valley fever case locations were mapped to corresponding climate data anomalies to understand associations between specific anomaly patterns in ecological and climate variables and disease outbreak patterns through space and time. From these maps we explored associations among Rift Valley fever disease occurrence locations and cumulative rainfall and vegetation index anomalies. We illustrated the time lag between the driving climate conditions and the timing of the first case of Rift Valley fever. Results showed that reported outbreaks of Rift Valley fever occurred after ∼3–4 months of sustained above-normal rainfall and associated green-up in vegetation, conditions ideal for Rift Valley fever mosquito vectors. For chikungunya we explored associations among surface air temperature, precipitation anomalies, and chikungunya outbreak locations. We found that chikungunya outbreaks occurred under conditions of anomalously high temperatures and drought over Eastern Africa. However, in Southeast Asia, chikungunya outbreaks were negatively correlated (p<0.05) with drought conditions, but positively correlated with warmer-than-normal temperatures and rainfall. Conclusions/Significance Extremes in climate conditions forced by the El Niño/Southern Oscillation (ENSO) lead to severe droughts or floods, ideal ecological conditions for disease vectors to emerge, and may result in epizootics and epidemics of Rift Valley fever and chikungunya. However, the immune status of livestock (Rift Valley fever) and human (chikungunya) populations is a factor that is largely unknown but very likely plays a role in the spatial-temporal patterns of these disease outbreaks. As the frequency and severity of extremes in climate increase, the potential for globalization of vectors and disease is likely to accelerate. Understanding the underlying patterns of global and regional climate variability and their impacts on ecological drivers of vector-borne diseases is critical in long-range planning of appropriate disease and disease-vector response, control, and mitigation strategies. PMID:22292093

Climate teleconnections and recent patterns of human and animal disease outbreaks.

PubMed

Anyamba, Assaf; Linthicum, Kenneth J; Small, Jennifer L; Collins, Kathrine M; Tucker, Compton J; Pak, Edwin W; Britch, Seth C; Eastman, James Ronald; Pinzon, Jorge E; Russell, Kevin L

2012-01-01

Recent clusters of outbreaks of mosquito-borne diseases (Rift Valley fever and chikungunya) in Africa and parts of the Indian Ocean islands illustrate how interannual climate variability influences the changing risk patterns of disease outbreaks. Although Rift Valley fever outbreaks have been known to follow periods of above-normal rainfall, the timing of the outbreak events has largely been unknown. Similarly, there is inadequate knowledge on climate drivers of chikungunya outbreaks. We analyze a variety of climate and satellite-derived vegetation measurements to explain the coupling between patterns of climate variability and disease outbreaks of Rift Valley fever and chikungunya. We derived a teleconnections map by correlating long-term monthly global precipitation data with the NINO3.4 sea surface temperature (SST) anomaly index. This map identifies regional hot-spots where rainfall variability may have an influence on the ecology of vector borne disease. Among the regions are Eastern and Southern Africa where outbreaks of chikungunya and Rift Valley fever occurred 2004-2009. Chikungunya and Rift Valley fever case locations were mapped to corresponding climate data anomalies to understand associations between specific anomaly patterns in ecological and climate variables and disease outbreak patterns through space and time. From these maps we explored associations among Rift Valley fever disease occurrence locations and cumulative rainfall and vegetation index anomalies. We illustrated the time lag between the driving climate conditions and the timing of the first case of Rift Valley fever. Results showed that reported outbreaks of Rift Valley fever occurred after ∼3-4 months of sustained above-normal rainfall and associated green-up in vegetation, conditions ideal for Rift Valley fever mosquito vectors. For chikungunya we explored associations among surface air temperature, precipitation anomalies, and chikungunya outbreak locations. We found that chikungunya outbreaks occurred under conditions of anomalously high temperatures and drought over Eastern Africa. However, in Southeast Asia, chikungunya outbreaks were negatively correlated (p<0.05) with drought conditions, but positively correlated with warmer-than-normal temperatures and rainfall. Extremes in climate conditions forced by the El Niño/Southern Oscillation (ENSO) lead to severe droughts or floods, ideal ecological conditions for disease vectors to emerge, and may result in epizootics and epidemics of Rift Valley fever and chikungunya. However, the immune status of livestock (Rift Valley fever) and human (chikungunya) populations is a factor that is largely unknown but very likely plays a role in the spatial-temporal patterns of these disease outbreaks. As the frequency and severity of extremes in climate increase, the potential for globalization of vectors and disease is likely to accelerate. Understanding the underlying patterns of global and regional climate variability and their impacts on ecological drivers of vector-borne diseases is critical in long-range planning of appropriate disease and disease-vector response, control, and mitigation strategies.

Phosphorylation-specific status of RNAi triggers in pharmacokinetic and biodistribution analyses

PubMed Central

Trubetskoy, Vladimir S.; Griffin, Jacob B.; Nicholas, Anthony L.; Nord, Eric M.; Xu, Zhao; Peterson, Ryan M.; Wooddell, Christine I.; Rozema, David B.; Wakefield, Darren H.; Lewis, David L.

2017-01-01

Abstract The RNA interference (RNAi)-based therapeutic ARC-520 for chronic hepatitis B virus (HBV) infection consists of a melittin-derived peptide conjugated to N-acetylgalactosamine for hepatocyte targeting and endosomal escape, and cholesterol-conjugated RNAi triggers, which together result in HBV gene silencing. To characterize the kinetics of RNAi trigger delivery and 5΄-phosphorylation of guide strands correlating with gene knockdown, we employed a peptide-nucleic acid (PNA) hybridization assay. A fluorescent sense strand PNA probe binding to RNAi duplex guide strands was coupled with anion exchange high performance liquid chromatography to quantitate guide strands and metabolites. Compared to PCR- or ELISA-based methods, this assay enables separate quantitation of non-phosphorylated full-length guide strands from 5΄-phosphorylated forms that may associate with RNA-induced silencing complexes (RISC). Biodistribution studies in mice indicated that ARC-520 guide strands predominantly accumulated in liver. 5΄-phosphorylation of guide strands was observed within 5 min after ARC-520 injection, and was detected for at least 4 weeks corresponding to the duration of HBV mRNA silencing. Guide strands detected in RISC by AGO2 immuno-isolation represented 16% of total 5΄-phosphorylated guide strands in liver, correlating with a 2.7 log10 reduction of HBsAg. The PNA method enables pharmacokinetic analysis of RNAi triggers, elucidates potential metabolic processing events and defines pharmacokinetic-pharmacodynamic relationships. PMID:28180327

Nematicidal Activity of Kojic Acid Produced by Aspergillus oryzae against Meloidogyne incognita.

PubMed

Kim, Tae Yoon; Jang, Ja Yeong; Jeon, Sun Jeong; Lee, Hye Won; Bae, Chang-Hwan; Yeo, Joo Hong; Lee, Hyang Burm; Kim, In Seon; Park, Hae Woong; Kim, Jin-Cheol

2016-08-28

The fungal strain EML-DML3PNa1 isolated from leaf of white dogwood (Cornus alba L.) showed strong nematicidal activity with juvenile mortality of 87.6% at a concentration of 20% fermentation broth filtrate at 3 days after treatment. The active fungal strain was identified as Aspergillus oryzae, which belongs to section Flavi, based on the morphological characteristics and sequence analysis of the ITS rDNA, calmodulin (CaM), and β-tubulin (BenA) genes. The strain reduced the pH value to 5.62 after 7 days of incubation. Organic acid analysis revealed the presence of citric acid (515.0 mg/kg), malic acid (506.6 mg/kg), and fumaric acid (21.7 mg/kg). The three organic acids showed moderate nematicidal activities, but the mixture of citric acid, malic acid, and fumaric acid did not exhibit the full nematicidal activity of the culture filtrate of EML- DML3PNa1. Bioassay-guided fractionation coupled with (1)H- and (13)C-NMR and EI-MS analyses led to identification of kojic acid as the major nematicidal metabolite. Kojic acid exhibited dose-dependent mortality and inhibited the hatchability of M. incognita, showing EC50 values of 195.2 µg/ml and 238.3 µg/ml, respectively, at 72 h postexposure. These results suggest that A. oryzae EML-DML3PNa1 and kojic acid have potential as a biological control agent against M. incognita.

Size and morphology controlled NiSe nanoparticles as efficient catalyst for the reduction reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subbarao, Udumula; Marakatti, Vijaykumar S.; Amshumali, Mungalimane K.

Facile and efficient ball milling and polyol methods were employed for the synthesis of nickel selenide (NiSe) nanoparticle. The particle size of the NiSe nanoparticle has been controlled mechanically by varying the ball size in the milling process. The role of the surfactants in the formation of various morphologies was studied. The compounds were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray energy dispersive spectroscopy (EDS). The efficiency of the NiSe nanoparticle as a catalyst was tested for the reduction of para-nitroaniline (PNA) to para-phenyldiamine (PPD) and para-nitrophenol (PNP) to para-aminophenol (PAP)more » using NaBH{sub 4} as the reducing agent. Particle size, morphology and the presence of surfactant played a crucial role in the reduction process. - Graphical abstract: NiSe nanoparticles in different size and morphology were synthesized using facile ball milling and polyol methods. Particle size, morphology and the presence of surfactant in these materials played a crucial role in the hydrogenation of PNA and PNP. - Highlights: • NiSe nanoparticles synthesized using ball milling and solution phase methods. • NiSe nanoparticle is an efficient catalyst for the reduction of PNA and PNP. • NiSe is found to be better than the best reported noble metal catalysts.« less

Identification of cell surface glycoprotein markers for glioblastoma-derived stem-like cells using a lectin microarray and LC-MS/MS approach

PubMed Central

He, Jintang; Liu, Yashu; Xie, Xiaolei; Zhu, Thant; Soules, Mary; DiMeco, Francesco; Vescovi, Angelo L.; Fan, Xing; Lubman, David M.

2010-01-01

Despite progress in the treatment of glioblastoma, more than 95% of patients suffering from this disease still die within two years. Recent findings support the belief that cancer stem-like cells are responsible for tumor formation and ongoing growth. Here a method combining lectin microarray and LC-MS/MS was used to discover the cell surface glycoprotein markers of a glioblastoma-derived stem-like cell line. Lectin microarray analysis of cell surface glycans showed that two galactose-specific lectins Trichosanthes kirilowii agglutinin (TKA) and Peanut agglutinin (PNA) could distinguish the stem-like glioblastoma neurosphere culture from a traditional adherent glioblastoma cell line. Agarose-bound TKA and PNA were used to capture the glycoproteins from the two cell cultures, which were analyzed by LC-MS/MS. The glycoproteins were quantified by spectral counting, resulting in the identification of 12 and 11 potential glycoprotein markers from the TKA and PNA captured fractions respectively. Almost all of these proteins were membrane proteins. Differential expression was verified by Western blotting analysis of 6 interesting proteins, including the up-regulated Receptor-type tyrosine-protein phosphatase zeta, Tenascin-C, Chondroitin sulfate proteoglycan NG2, Podocalyxin-like protein 1 and CD90, and the down-regulated CD44. An improved understanding of these proteins may be important for earlier diagnosis and better therapeutic targeting of glioblastoma. PMID:20235609

Influence of copper surfaces on biofilm formation by Legionella pneumophila in potable water.

PubMed

Gião, M S; Wilks, S A; Keevil, C W

2015-04-01

Legionella pneumophila is a waterborne pathogen that can cause Legionnaires' disease, a fatal pneumonia, or Pontiac fever, a mild form of disease. Copper is an antimicrobial material used for thousands of years. Its incorporation in several surface materials to control the transmission of pathogens has been gaining importance in the past decade. In this work, the ability of copper to control the survival of L. pneumophila in biofilms was studied. For that, the incorporation of L. pneumophila in polymicrobial drinking water biofilms formed on copper, PVC and PEX, and L. pneumophila mono-species biofilms formed on copper and uPVC were studied by comparing cultivable and total numbers (quantified by peptide nucleic acid (PNA) hybridisation). L. pneumophila was never recovered by culture from heterotrophic biofilms; however, PNA-positive numbers were slightly higher in biofilms formed on copper (5.9 × 10(5) cells cm(-2)) than on PVC (2.8 × 10(5) cells cm(-2)) and PEX (1.7 × 10(5) cells cm(-2)). L. pneumophila mono-species biofilms grown on copper gave 6.9 × 10(5) cells cm(-2) for PNA-positive cells and 4.8 × 10(5) CFU cm(-2) for cultivable numbers, showing that copper is not directly effective in killing L. pneumophila. Therefore previous published studies showing inactivation of L. pneumophila by copper surfaces in potable water polymicrobial species biofilms must be carefully interpreted.

Absorption characteristics of epidural levobupivacaine with adrenaline and clonidine in children.

PubMed

Chalkiadis, George A; Abdullah, Farah; Bjorksten, Andrew R; Clarke, Alexander; Cortinez, Luis I; Udayasiri, Sonal; Anderson, Brian J

2013-01-01

To determine if the addition of adrenaline, clonidine, or their combination altered the pharmacokinetic profile of levobupivacaine administered via the caudal epidural route in children. Children aged <18 years old scheduled to undergo sub-umbilical surgery were administered caudal levobupivacaine plain 2.5 mg · ml(-1) or with adjuvants adrenaline 5 mcg · ml(-1) or clonidine 2 mcg · ml(-1) or their combination. Covariate analysis included weight and postnatal age (PNA). Time-concentration profile analysis was undertaken using nonlinear mixed effects models. A one-compartment linear disposition model with first-order input and first-order elimination was used to describe the data. The effect of either clonidine or adrenaline on absorption was investigated using a scaling parameter (Fabs(CLON), Fabs(ADR)) applied to the absorption half-life (Tabs). There were 240 children (median weight 11.0, range 1.9-56.1 kg; median postnatal age 16.7, range 0.6-167.6 months). Absorption of levobupivacaine was faster when mixed with clonidine (Fabs(CLON) 0.60; 95%CI 0.44, 0.83) but slower when mixed with adrenaline (Fabs(ADR) 2.12; 95%CI 1.45, 3.08). The addition of adrenaline to levobupivacaine resulted in a bifid absorption pattern. While initial absorption was unchanged (Tabs 0.15 h 95%CI 0.12, 0.18 h), there was a late absorption peak characterized by a Tabs(LATE) 2.34 h (95%CI 1.44, 4.97 h). The additional use of clonidine with adrenaline had minimal effect on the bifid absorption profile observed with adrenaline alone. Neither clonidine nor adrenaline had any effect on clearance. The population parameter estimate for volume of distribution was 157 l 70 kg(-1). Clearance was 6.5 l · h(-1) 70 kg(-1) at 1-month PNA and increased with a maturation half-time of 1.6 months to reach 90% of the mature value (18.5 l · h(-1) 70 kg(-1)) by 5 months PNA. The addition of adrenaline decreases the rate of levobupivacaine systemic absorption, reducing peak concentration by half. Levobupivacaine concentrations with adrenaline adjuvant were reduced compared to plain levobupivacaine for up to 3.5 hours. Clonidine as an adjuvant results in faster systemic absorption of levobupivacaine and similar concentration time profile to levobupivacaine alone. Adding adrenaline with clonidine does not alter the concentration profile observed with adrenaline alone. © 2012 Blackwell Publishing Ltd.