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  1. Uncorrected refractive error and associated factors among primary school children in Debre Markos District, Northwest Ethiopia

    PubMed Central

    2014-01-01

    Background Uncorrected Refractive Error is one of the leading cause amblyopia that exposes children to poor school performance. It refrain them from productive working lives resulting in severe economic and social loses in their latter adulthood lives. The objective of the study was to assess the prevalence of uncorrected refractive error and its associated factors among school children in Debre Markos District. Method A cross section study design was employed. Four hundred thirty two students were randomly selected using a multistage stratified sampling technique. The data were collected by trained ophthalmic nurses through interview, structured questionnaires and physical examinations. Snellens visual acuity measurement chart was used to identify the visual acuity of students. Students with visual acuity less than 6/12 had undergone further examination using auto refractor and cross-checked using spherical and cylindrical lenses. The data were entered into epi data statistical software version 3.1 and analyzed by SPSS version 20. The statistical significance was set at α ≤ 0.05. Descriptive, bivariate and multivariate analyses were done using odds ratios with 95% confidence interval. Result Out of 432 students selected for the study, 420 (97.2%) were in the age group 7–15 years. The mean age was 12 ± 2.1SD. Overall prevalence of refractive error was 43 (10.2%). Myopia was found among the most dominant 5.47% followed by astigmatism 1.9% and hyperopia 1.4% in both sexes. Female sex (AOR: 3.96, 95% CI: 1.55-10.09), higher grade level (AOR: 4.82, 95% CI: 1.98-11.47) and using computers regularly (AOR: 4.53, 95% CI: 1.58-12.96) were significantly associated with refractive error. Conclusion The burden of uncorrected refractive errors is high among primary schools children. Myopia was common in both sexes. The potential risk factors were sex, regular use of computers and higher grade level of students. Hence, school health programs should work on health

  2. Ciguatera fish poisoning in Hong Kong--a 10-year perspective on the class of ciguatoxins.

    PubMed

    Wong, Chun-Kwan; Hung, Patricia; Lo, Janice Y C

    2014-08-01

    The present study used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate retrospectively ciguatoxin (CTX)-positive samples as determined by mouse bioassay (MBA) in the past 10 years in Hong Kong. The results showed that Pacific CTXs (P-CTX-1, -2 and -3) were the most commonly observed toxins found in the samples, indicating Pacific Ocean areas as the most important origin of ciguatera fish poisoning. Clinical diagnosis from ciguatera patients also revealed the predominance of neurological illnesses in most cases, supporting intoxication of Pacific origin. This study demonstrated the ability of laboratory analysis to identify and quantify Pacific CTXs in suspected fish samples, so as to support the clinical diagnosis of ciguatera. Comparative analysis (Student's t-test and Spearman's rank correlation analysis) on the two CTX detection methods showed approximate linearity for overall P-CTXs (P-CTX-1, -2 and -3)/P-CTX-1 alone as derived by LC-MS/MS and total toxicity levels (P-CTX-1 equivalent) as determined by MBA. The LC-MS/MS method coupled with the rapid extraction method could allow the detection of trace amount of CTXs at levels below the clinically relevant limit, 0.1 ppb P-CTX-1 in fish flesh. For practical application, the adoption of a two-tiered approach for testing, chemical analysis by LC-MS/MS for toxic fish screening, coupled with biological assay by MBA for final toxicity confirmation, was proposed for first-line screening of CTX in potentially contaminated fish samples in the market, with an aim to minimizing the use of laboratory mice and at the same time providing reasonably effective means for routine analysis. PMID:24878373

  3. Physical measurements of Chinese children in Hong Kong-A pilot study in preschools and kindergartens.

    PubMed

    Mok, Gary T K; Chan, Sharon S; Chu, Yoyo W Y; Chan, Sau Man; Wong, Wilfred H S; Chung, Brian H Y

    2016-08-01

    Normal growth is essential to a developing child. Most syndromes with dysmorphic features demonstrate recognizable patterns of disproportionate growth, thus physical measurements are an important aspect of patient evaluation. Delineating the abnormal growth pattern depends greatly on the accuracy of the normal range. However, the currently available reference data are restricted in terms of ethnicity and geographical location, hence may not be applicable to all children worldwide. In Hong Kong, reference data are limited only to the neonatal period. The aim of our pilot study is to obtain a set of region-specific physical measurement data for Chinese children in Hong Kong. Two to six year olds were recruited from preschools and kindergartens in different regions of Hong Kong. Twenty-six parameters found in previous publications were measured with minor modifications. Three medical personnel trained by a clinical geneticist obtained these parameters. Satisfactory inter-rater reliability was achieved in a training cohort prior to the study. Raw measurement data collected were normalized and fitted into growth curves modeled by LMS method. We recruited 448 children (55.6% male) between 2 and 6 years old from five preschools and kindergartens. Growth curves with essential percentile lines were drawn. Significant differences were identified in 11 parameters when compared with Caucasian children, including canthal distances and facial width/height. Our current pilot study presents the first local- and ethnicity-specific data on physical measurements of 2-6 year olds. Our findings highlighted the substantial ethnic variability in physical measurements and the need for an ethnic-specific reference for Chinese children. © 2016 Wiley Periodicals, Inc. PMID:27244049

  4. Attitudes toward Euthanasia in Hong Kong--A Comparison between Physicians and the General Public

    ERIC Educational Resources Information Center

    Chong, Alice Ming-lin; Fok, Shiu-yeu

    2005-01-01

    This article reports the findings of a cross-sectional study that compared the attitudes of 618 respondents of a general household survey and a random sample of 1,197 physicians toward different types of euthanasia in Hong Kong. The general public was found to agree with active euthanasia and non-voluntary euthanasia and was neutral about passive…

  5. Reggio Experiences in Hong Kong--A Touch of Chinese Culture: The Sheung Wan Story and Chinese Opera Project

    ERIC Educational Resources Information Center

    Lee Lai Wan, Maria; Tsang Kam Shau Wan, Sanly

    2005-01-01

    This paper reports two projects done by children in Hong Kong, adapting the Reggio experience to fit the local needs of the community and the children. As Carla Rinaldi said, children are constantly "in search of meaning, finding the sense and meaning of things we do" (Lee, 2001, p. 29). The first project documented how children of the Lee Wai Lee…

  6. Postnatal Care Service Utilization and Associated Factors among Women Who Gave Birth in the Last 12 Months prior to the Study in Debre Markos Town, Northwestern Ethiopia: A Community-Based Cross-Sectional Study

    PubMed Central

    Limenih, Miteku Andualem; Endale, Zerfu Mulaw; Dachew, Berihun Assefa

    2016-01-01

    Improving maternal and newborn health through proper postnatal care services under the care of skilled health personnel is the key strategy to reduce maternal and neonatal mortality. However, there were limited evidences on utilization of postnatal care services in Ethiopia. A community based cross-sectional study was conducted in Debremarkos town, Northwest Ethiopia. Cluster sampling technique was used to select 588 study participants. Bivariate and multivariable logistic regression model was fitted to identify factors associated with postnatal care utilization. Odds ratio with 95% confidence interval was computed to determine the level of significance. Postnatal care service utilization was found to be 33.5%. Awareness about maternal complication (AOR: 2.72, 95% CI (1.71, 4.34)), place of delivery of last child (AOR: 1.68, 95% CI: (1.01, 2.79)), outcome of birth (AOR: 2.71, 95% CI (1.19, 6.19)), delivery by cesarean section (AOR: 4.82, 95% CI (1.86, 12.54)), and delivery complication that occurred during birth (AOR: 2.58, 95% CI (1.56, 4.28)) were factors associated with postnatal care service utilization. Postnatal care service utilization was found to be low. Increasing awareness about postnatal care, preventing maternal and neonatal complication, and scheduling mothers based on the national postnatal care follow-up protocol would increase postnatal care service utilization. PMID:27433481

  7. Current Level and Correlates of Traditional Cooking Energy Sources Utilization in Urban Settings in the Context of Climate Change and Health, Northwest Ethiopia: A Case of Debre Markos Town

    PubMed Central

    Geremew, Kumlachew; Gedefaw, Molla; Dagnew, Zewdu; Jara, Dube

    2014-01-01

    Background. Traditional biomass has been the major source of cooking energy for major segment of Ethiopian population for thousands of years. Cognizant of this energy poverty, the Government of Ethiopia has been spending huge sum of money to increase hydroelectric power generating stations. Objective. To assess current levels and correlates of traditional cooking energy sources utilization. Methods. A community based cross-sectional study was conducted employing both quantitative and qualitative approaches on systematically selected 423 households for quantitative and purposively selected 20 people for qualitative parts. SPSS version 16 for windows was used to analyze the quantitative data. Logistic regression was fitted to assess possible associations and its strength was measured using odds ratio at 95% CI. Qualitative data were analyzed thematically. Result. The study indicated that 95% of households still use traditional biomass for cooking. Those who were less knowledgeable about negative health and environmental effects of traditional cooking energy sources were seven and six times more likely to utilize them compared with those who were knowledgeable (AOR (95% CI) = 7.56 (1.635, 34.926), AOR (95% CI) = 6.68 (1.80, 24.385), resp.). The most outstanding finding of this study was that people use traditional energy for cooking mainly due to lack of the knowledge and their beliefs about food prepared using traditional energy. That means “…people still believe that food cooked with charcoal is believed to taste delicious than cooked with other means.”  Conclusion. The majority of households use traditional biomass for cooking due to lack of knowledge and belief. Therefore, mechanisms should be designed to promote electric energy and to teach the public about health effects of traditional cooking energy source. PMID:24895591

  8. Postnatal Care Service Utilization and Associated Factors among Women Who Gave Birth in the Last 12 Months prior to the Study in Debre Markos Town, Northwestern Ethiopia: A Community-Based Cross-Sectional Study.

    PubMed

    Limenih, Miteku Andualem; Endale, Zerfu Mulaw; Dachew, Berihun Assefa

    2016-01-01

    Improving maternal and newborn health through proper postnatal care services under the care of skilled health personnel is the key strategy to reduce maternal and neonatal mortality. However, there were limited evidences on utilization of postnatal care services in Ethiopia. A community based cross-sectional study was conducted in Debremarkos town, Northwest Ethiopia. Cluster sampling technique was used to select 588 study participants. Bivariate and multivariable logistic regression model was fitted to identify factors associated with postnatal care utilization. Odds ratio with 95% confidence interval was computed to determine the level of significance. Postnatal care service utilization was found to be 33.5%. Awareness about maternal complication (AOR: 2.72, 95% CI (1.71, 4.34)), place of delivery of last child (AOR: 1.68, 95% CI: (1.01, 2.79)), outcome of birth (AOR: 2.71, 95% CI (1.19, 6.19)), delivery by cesarean section (AOR: 4.82, 95% CI (1.86, 12.54)), and delivery complication that occurred during birth (AOR: 2.58, 95% CI (1.56, 4.28)) were factors associated with postnatal care service utilization. Postnatal care service utilization was found to be low. Increasing awareness about postnatal care, preventing maternal and neonatal complication, and scheduling mothers based on the national postnatal care follow-up protocol would increase postnatal care service utilization. PMID:27433481

  9. User's Guide and Metadata to Coastal Biodiversity Risk Analysis Tool (CBRAT): Framework for the Systemization of Life History and Biogeographic Information

    EPA Science Inventory

    ABSTRACTUser’s Guide & Metadata to Coastal Biodiversity Risk Analysis Tool (CBRAT): Framework for the Systemization of Life History and Biogeographic Information(EPA/601/B-15/001, 2015, 123 pages)Henry Lee II, U.S. EPA, Western Ecology DivisionKatharine Marko, U.S. EPA,...

  10. Spring Research Festival Features Visit from FCPS Superintendent | Poster

    Cancer.gov

    One of the highlights of the 19th annual Spring Research Festival (SRF), held May 4–7, was a visit from Terry Alban, Ph.D., superintendent of Frederick County Public Schools (FCPS), and Mike Markoe, deputy superintendent, FCPS. They toured the event on May 7, talking to researchers and students about their posters. “Dr. Alban was very interested in hearing what the Werner H. Kirsten students were presenting at their posters,” said Andrea Frydl, public affairs specialist, Office of Scientific Operations, NCI at Frederick. “Many WHK students are also FCPS students, some of whom Dr. Alban and Dr. Markoe knew personally.” Alban tweeted (@FCPSMDSuper) photos and information about four of the students whose posters she visited during the tour.

  11. Role of chain entropy in an analytic model of protein binding in single-DNA stretching experiments.

    PubMed

    Lam, Pui-Man; Neumann, Richard M

    2011-09-01

    We show that the simple analytical model proposed by Zhang and Marko [Phys. Rev. E 77, 031916 (2008)] to illustrate Maxwell relations for single-DNA experiments can be improved by including the zero-force entropy of a Gaussian chain. The resulting model is in excellent agreement with the discrete persistent-chain model and is in a form convenient for analyzing experimental data. PMID:22060437

  12. This Car Seems to Be Alive--Perspectives on the Documentary, "Plan F"

    ERIC Educational Resources Information Center

    Quinlan, Margaret M.; Smith, J. Webster; Hayward, Casey

    2009-01-01

    Ed Marko redefines what it means to be not only an auto mechanic but also a person who is blind. At the age of 20 years, he lost his sight from a degenerative disease called infantile glaucoma. However, he has surpassed what we traditionally think of as the capabilities of blind people. Now in his late 60s, he was once a rehabilitation counsellor,…

  13. Left-handed materials and negative refraction: Transfer matrix and FDTD calculations

    NASA Astrophysics Data System (ADS)

    Soukoulis, Costas M.

    2004-03-01

    We will present transfer matrix calculations of metallic wires, split ring resonators (SRR) and left-handed materials (LHM). Our results [1] show that the transfer matrix method can capture all the details characteristics of the metamaterials. In particular the dependence of the resonance frequency and its width on the structural parameters of the SRR and the size of the unit cell is studied. Also the dependence of the imaginary part of effective permittivity of arrays of metallic wires is studied in detail. It is found [2,3] that the imaginary part of effective permittivity has small values even for wires as small as 20 micron in diameter. The transfer matrix is very useful in calculating both the amplitude and the phase of the transmission and reflection coefficient. These numerical data was used [4] in the determination of the effective parameters of the metamaterials. It was indeed found that the refractive index was unambiguously negative in the frequency region where both ɛ and μ were negative. Finally, we will show that SRR have a strong electric response, equivalent to that of cut wires [5], which dominates the response of LHM. A new criterion is introduced to clearly identify if an experimental expression peak is left- or right handed. Finite difference time domain (FDTD) simulations will be presented for the transmission of the EM wave through the interface of the positive and negative refraction index. It is found [6] that the wave is trapped temporarily at the interface and after a long time the wave front moves eventually in the direction of negative refraction. The differences between negative refraction in photonic crystals and left-handed materials will be also discussed. Work supported by US-DOE, DARPA, NSF and EU (DALHM project). References: [1] P. Markos and C. M. Soukoulis, Phys. Rev. B 65, 033401 (2002); Phys. Rev. E 65, 036622 (2002). [2] P. Markos, I. Rousochatzakis and C. M. Soukoulis, Phys. Rev. B 66, 045601 (2002). [3] P. Markos and C. M

  14. Simulation of λ-phage DNA in microchannels using a coarse-grained MD method

    NASA Astrophysics Data System (ADS)

    Symeonidis, Vasileios

    2005-11-01

    In this work we present Dissipative Particle Dynamics (dpd) simulations of polymers subject to the Marko-Siggia wormlike chain (wlc) spring law. We demonstrate the advantages of Lowe's dpd method, which simulates high Schmidt numbers for the solvent, and contrast it with the velocity-Verlet scheme. Shear flow results for the wormlike chain (wlc) simulating single dna molecules compare well with average extensions from experiments, irrespective of the number of beads. However, coarse-graining with more than a few beads degrades the agreement of the autocorrelation of the extension.

  15. Polymer chain simulations in microchannels with Dissipative Particle Dynamics

    NASA Astrophysics Data System (ADS)

    Symeonidis, Vasileios; Karniadakis, George; Caswell, Bruce

    2006-03-01

    In this work we employ Dissipative Particle Dynamics (dpd) for simulations of dilute polymer solutions using bead-spring representations. We present comparison of two time-marching schemes: the popular velocity-Verlet and Lowe's scheme. Schmidt number effects are investigated for a series of cases, including λ-dna molecules under shear (using the Marko-Siggia wormlike chain spring law) and Poiseuille flow in microchannels. Effects on the polymer depletion layer, power-law profiles and apparent viscosities are presented as a function of the number of beads per polymer chain.

  16. A kinetic proofreading mechanism for disentanglement of DNA by topoisomerases

    NASA Astrophysics Data System (ADS)

    Yan, Jie; Magnasco, Marcelo O.; Marko, John

    2000-03-01

    Cells must remove all entanglements between their replicated chromosomal DNAs to segregate them during cell division. Entanglement removal is done by ATP-driven enzymes which pass DNA strands through one another, called type II topoisomerases (topos). In vitro some type II topos can reduce entanglements to a level much below that expected given the assumption that they pass DNA segments through one another at random. These type II topos (of less than 10 nm in diameter) thus use ATP hydrolysis to sense and remove entanglements spread along up to 3000 nm-long flexible DNAs. We propose a mechanism for this, based on the higher rate of collisions along DNAs which are entangled, relative to rates on disentangled DNAs. We show that if a type II topo requires an initial `activating' collision in advance of a second strand-passing collision, it can reduce the probability of entanglement to experimentally observed levels. This two-collision reaction is similar to `kinetic proofreading' models of molecular recognition. This talk will briefly review the experimental results, summurize the key points of our model, and report the rates of collisions of both entangled and disentangled DNAs obtained by Brownian Dynamical Simulation. We acknowledge support of the NSF, Research Corporation, the Petroleum Research Fund, and the Whitaker Foundation. MOM acknowledges support of the Sloan Foundation and the Mathers Foundation. Ref: JIE YAN, MARCELO O. MAGNASCO, and JOHN F. MARKO, Nature 401, 932-935 (1999).

  17. Polymer extension under flow: A path integral evaluation of the free energy change using the Jarzynski relation.

    PubMed

    Ghosal, Aishani; Cherayil, Binny J

    2016-06-01

    The Jarzynski relation (and its variants) has provided a route to the experimental evaluation of equilibrium free energy changes based on measurements conducted under arbitrary non-equilibrium conditions. Schroeder and co-workers [Soft Matter 10, 2178 (2014) and J. Chem. Phys. 141, 174903 (2014)] have recently exploited this fact to determine the elastic properties of model DNA from simulations and experiments of chain extension under elongational flow, bypassing the need to make these measurements mechanically using sophisticated optical trapping techniques. In this paper, motivated by these observations, we investigate chain elasticity analytically, using the Jarzynski relation and a finitely extensible nonlinear elastic-type Rouse model within a path integral formalism to calculate (essentially exactly) both the flow-induced free energy change between chain conformations of definite average end-to-end distance, as well as the force-extension curve that follows from it. This curve, based on a new analytic expression, matches the trends in the corresponding curve obtained from a model of chain stretching developed by Marko and Siggia [Macromolecules 28, 8759 (1995)], which itself is in very satisfactory agreement with the numerical and experimental data from the work of Schroeder et al. PMID:27276965

  18. Polymer extension under flow: A path integral evaluation of the free energy change using the Jarzynski relation

    NASA Astrophysics Data System (ADS)

    Ghosal, Aishani; Cherayil, Binny J.

    2016-06-01

    The Jarzynski relation (and its variants) has provided a route to the experimental evaluation of equilibrium free energy changes based on measurements conducted under arbitrary non-equilibrium conditions. Schroeder and co-workers [Soft Matter 10, 2178 (2014) and J. Chem. Phys. 141, 174903 (2014)] have recently exploited this fact to determine the elastic properties of model DNA from simulations and experiments of chain extension under elongational flow, bypassing the need to make these measurements mechanically using sophisticated optical trapping techniques. In this paper, motivated by these observations, we investigate chain elasticity analytically, using the Jarzynski relation and a finitely extensible nonlinear elastic-type Rouse model within a path integral formalism to calculate (essentially exactly) both the flow-induced free energy change between chain conformations of definite average end-to-end distance, as well as the force-extension curve that follows from it. This curve, based on a new analytic expression, matches the trends in the corresponding curve obtained from a model of chain stretching developed by Marko and Siggia [Macromolecules 28, 8759 (1995)], which itself is in very satisfactory agreement with the numerical and experimental data from the work of Schroeder et al.

  19. The use of the RBI nuclear microprobe in conservation process studies of a church portal

    NASA Astrophysics Data System (ADS)

    Pastuović, Ž.; Fazinić, S.; Jakšić, M.; Krstić, D.; Mudronja, D.

    2005-04-01

    The southern portal of the St. Marko church in Zagreb, Croatia, is currently under the process of conservation. The conservation treatments on calcareous sandstone consist of (i) removal of harmful sulfates (gypsum) from the surface of the material by saturated solution of ammonium carbonate; and (ii) treatment of the material surface with a 10% solution of barium hydroxide in order to convert the remaining dissolvable sulfates into non-dissolvable compounds and to strengthen the material surface. The nuclear microprobe has been used to measure the level of gypsum induced damage, and quality of conservation. More specifically, the surface quantity and depth concentration profiles of sulfur have been determined in several samples taken from the portal before and after the treatment with the solution of ammonium carbonate. To test the quality of treatment by the barium hydroxide solution, the depth concentration of barium in the samples has been determined after the treatment. Both sulfur and barium concentration levels have been determined by scanning the focused proton beam over the samples, detecting PIXE spectra and creating elemental distribution maps. Beside portal samples, the efficiency of the barium hydroxide treatment was tested on sandstone samples from nearby stone pit assumed to be the origin of material used for portal construction.

  20. Microelasticity of Single Mitotic Chromosomes

    NASA Astrophysics Data System (ADS)

    Poirier, Michael; Eroglu, Sertac; Chatenay, Didier; Marko, John F.; Hirano, Tatsuya

    2000-03-01

    The force-extension behavior of mitotic chromosomes from the newt TVI tumor cell line was studied using micropipette manipulation and force measuring techniques. Reversible, linear elastic response was observed for extensions up to 5 times the native length; the force required to double chromosome length was 1 nanonewton (nN). For further elongations, the linear response teminates at a force plateau of 15 nN and at an extension of 20x. Beyond this extension, the chromosome breaks at elongations between 20x and 70x. These results will be compared to the similar behavior of mitotic chromosomes from explanted newt cells (Poirier, Eroglu, Chatenay and Marko, Mol. Biol. Cell, in press). Also, the effect of biochemical modifications on the elasticity was studied. Ethidium Bromide, which binds to DNA, induces up to a 10 times increase in the Young's modulus. Anti-XCAP-E, which binds to a putative chromosome folding protein, induces up to a 2 times increase in the Young's modulus. Preliminary results on the dynamical relaxation of chromosomes will also be presented. Support of this research through a Biomedical Engineering Research Grant from The Whitaker Foundation is gratefully acknowledged.

  1. Advanced powder metallurgy aluminum alloys via rapid solidification technology, phase 2

    NASA Technical Reports Server (NTRS)

    Ray, Ranjan; Jha, Sunil C.

    1987-01-01

    Marko's rapid solidification technology was applied to processing high strength aluminum alloys. Four classes of alloys, namely, Al-Li based (class 1), 2124 type (class 2), high temperature Al-Fe-Mo (class 3), and PM X7091 type (class 4) alloy, were produced as melt-spun ribbons. The ribbons were pulverized, cold compacted, hot-degassed, and consolidated through single or double stage extrusion. The mechanical properties of all four classes of alloys were measured at room and elevated temperatures and their microstructures were investigated optically and through electron microscopy. The microstructure of class 1 Al-Li-Mg alloy was predominantly unrecrystallized due to Zr addition. Yield strengths to the order of 50 Ksi were obtained, but tensile elongation in most cases remained below 2 percent. The class 2 alloys were modified composition of 2124 aluminum alloy, through addition of 0.6 weight percent Zr and 1 weight percent Ni. Nickel addition gave rise to a fine dispersion of intermetallic particles resisting coarsening during elevated temperature exposure. The class 2 alloy showed good combination of tensile strength and ductility and retained high strength after 1000 hour exposure at 177 C. The class 3 Al-Fe-Mo alloy showed high strength and good ductility both at room and high temperatures. The yield and tensile strength of class 4 alloy exceeded those of the commercial 7075 aluminum alloy.

  2. Rate of recovery of Mycobacterium tuberculosis from frozen acid-fast-bacillus smear-positive sputum samples subjected to long-term storage in Northwest Ethiopia.

    PubMed

    Tessema, Belay; Beer, Joerg; Emmrich, Frank; Sack, Ulrich; Rodloff, Arne C

    2011-07-01

    Tuberculosis is a major public health problem in Ethiopia. The diagnosis and treatment of drug-resistant tuberculosis remain a challenge in the country. This study aimed to assess whether single morning sputum samples could be stored at -20 °C for extended periods of time at remote settings and then transported and successfully cultured for Mycobacterium tuberculosis. Single morning sputum samples were collected from all smear-positive tuberculosis patients diagnosed at Gondar Hospital, Gondar Health Center, Metemma Hospital, Bahir Dar Hospital, and Debre Markos Hospital in Northwest Ethiopia between March and July 2009. Specimens were stored at the study sites and sent to the mycobacteriology laboratory at the University Hospital, Leipzig, Germany, where specimens were processed and inoculated into the BacT/Alert 3D system and Lowenstein-Jensen and Gottsacker media. Ice packs were added in the package of the specimens during transport. A total of 319 patients were enrolled in this study. The median specimen storage time was 132 days (range, 16 to 180 days). Of all specimens, 283 (88.7%) were culture positive by any of the three culturing systems. M. tuberculosis isolates from four contaminated specimens in all culturing systems were successfully isolated on Middlebrook 7H10 agar; thereby, the recovery rate increased to 287 (90.0%). The length of time of sputum storage had no significant effect on the rate of recovery of M. tuberculosis in all culturing systems. In conclusion, single morning sputum specimens collected at remote settings stored at -20 °C for long periods of time without the addition of preservatives can yield a high recovery rate. These findings suggest a simple and cost-effective alternative method of sputum storage for epidemiological and drug resistance studies in low-resource countries. PMID:21562105

  3. Prediction of sea ice thickness cluster in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Fuckar, Neven-Stjepan; Guemas, Virginie; Johnson, Nathaniel; Doblas-Reyes, Francisco

    2016-04-01

    Sea ice thickness (SIT) has a potential to contain substantial climate memory and predictability in the northern hemisphere (NH) sea ice system. We use 5-member NH SIT, reconstructed with an ocean-sea-ice general circulation model (NEMOv3.3 with LIM2) with a simple data assimilation routine, to determine NH SIT modes of variability disentangled from the long-term climate change. Specifically, we apply the K-means cluster analysis - one of nonhierarchical clustering methods that partition data into modes or clusters based on their distances in the physical - to determine optimal number of NH SIT clusters (K=3) and their historical variability. To examine prediction skill of NH SIT clusters in EC-Earth2.3, a state-of-the-art coupled climate forecast system, we use 5-member ocean and sea ice initial conditions (IC) from the same ocean-sea-ice historical reconstruction and atmospheric IC from ERA-Interim reanalysis. We focus on May 1st and Nov 1st start dates from 1979 to 2010. Common skill metrics of probability forecast, such as rank probability skill core and ROC (relative operating characteristics - hit rate versus false alarm rate) and reliability diagrams show that our dynamical model predominately perform better than the 1st order Marko chain forecast (that beats climatological forecast) over the first forecast year. On average May 1st start dates initially have lower skill than Nov 1st start dates, but their skill is degraded at slower rate than skill of forecast started on Nov 1st.

  4. Catalytic Deprotection of Acetals In Strongly Basic Solution Usinga Self-Assembled Supramolecular 'Nanozyme'

    SciTech Connect

    Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

    2007-07-26

    Acetals are among the most commonly used protecting groups for aldehydes and ketones in organic synthesis due to their ease of installation and resistance to cleavage in neutral or basic solution.[1] The common methods for hydrolyzing acetals almost always involve the use of either Broensted acid or Lewis acid catalysts.[2] Usually aqueous acids or organic solutions acidified with organic or inorganic acids have been used for reconversion of the acetal functionality to the corresponding carbonyl group; however, recently a number of reports have documented a variety of strategies for acetal cleavage under mild conditions. These include the use of Lewis acids such as bismuth(III)[3] or cerium(IV),[4, 5] functionalized silica gel, such as silica sulfuric acid[6] or silica-supported pyridinium p-toluene sulfonate,[7] or the use of silicon-based reagents such as TESOTf-2,6-Lutidine.[8] Despite these mild reagents, all of the above conditions require either added acid or overall acidic media. Marko and co-workers recently reported the first example of acetal deprotection under mildly basic conditions using catalytic cerium ammonium nitrate at pH 8 in a water-acetonitrile solution.[5] Also recently, Rao and co-workers described a purely aqueous system at neutral pH for the deprotection of acetals using {beta}-cyclodextrin as the catalyst.[9] Herein, we report the hydrolysis of acetals in strongly basic aqueous solution using a self-assembled supramolecular host as the catalyst. During the last decade, we have used metal-ligand interactions for the formation of well-defined supramolecular assemblies with the stoichiometry M{sub 4}L{sub 6}6 (M = Ga{sup III} (1 refers to K{sub 12}[Ga{sub 4}L{sub 6}]), Al{sup III}, In{sup III}, Fe{sup III}, Ti{sup IV}, or Ge{sup IV}, L = N,N{prime}-bis(2,3-dihydroxybenzoyl)-1,5-diaminonaphthalene) (Figure 1).[10] The metal ions occupy the vertices of the tetrahedron and the bisbidentate catecholamide ligands span the edges. The strong

  5. PREFACE: The Universe under the Microscope: Astrophysics at High Angular Resolution

    NASA Astrophysics Data System (ADS)

    Schödel, Rainer

    2009-01-01

    Köln, Köln, Germany Eduardo Ros Max-Planck-Institut für extraterrestrische Physik, Bonn, Germany Scientific organizing committee Dennis Downes Institut de Radio Astronomie Millimétrique, France Wolfgang Duschl University of Kiel, Germany Andrea Ghez University of California, Los Angeles, USA Vladimir Karas Academy of Sciences, Czech Republic Andreas Eckart University of Cologne, Germany Sera Marko University of Amsterdam, The Netherlands Susanne Pfalzner University of Cologne, Germany Sebastian Rabien Max-Planck-Institute for Extraterrestrial Physics, Germany Daniel Rouan Observatoire de Paris-Meudon, France Eduardo Ros Max-Planck-Institute for Radio Astronomy, Germany Rainer Schödel Instituto de Astrofísica de Andalucía -CSIC, Spain Zhiqiang Shen Shanghai Astronomical Observatory, China Anton Zensus Max-Planck-Institute for Radio Astronomy, Germany Local organizing committee Sebastian Fischer University of Cologne, Germany Devaky Kunneriath University of Cologne, Germany Leo Meyer University of Cologne, Germany Koraljka Muzic University of Cologne, Germany Rainer Schödel University of Cologne, Germany/IAA -CSIC, Spain Christian Straubmeier University of Cologne, Germany Mohammad Zamaninasab University of Cologne, Germany

  6. Toward efficient fiber-based quantum interface (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Soshenko, Vladimir; Vorobyov, Vadim V.; Bolshedvorsky, Stepan; Lebedev, Nikolay; Akimov, Alexey V.; Sorokin, Vadim; Smolyaninov, Andrey

    2016-04-01

    , vol. 528, no. 1, p. 1-45, 2013. [2] A.V. Akimov, A. Mukherjee, C.L. Yu, D.E. Chang, A.S. Zibrov, P.R. Hemmer, H. Park and M.D. Lukin, "Generation of single optical plasmons in metallic nanowires coupled to quantum dots," Nature, vol. 450, p. 402-406, 2007. [3] Michael J. Burek , Yiwen Chu, Madelaine S.Z. Liddy, Parth Patel, Jake Rochman , Srujan Meesala, Wooyoung Hong, Qimin Quan, Mikhail D. Lukin and Marko Loncar High quality-factor optical nanocavities in bulk single-crystal diamond, Nature communications 6718 (2014) [4] Tim Schroder, Andreas W. Schell, Gunter Kewes, Thomas Aichele, and Oliver Benson Fiber-Integrated Diamond-Based Single Photon Source, Nano Lett. 2011, 11, 198-202 [5]Lars Liebermeister, et. al. "Tapered fiber coupling of single photons emitted by a deterministically positioned single nitrogen vacancy center", Appl. Phys. Lett. 104, 031101 (2014)

  7. EDITORIAL: Focus on Cold and Ultracold Molecules FOCUS ON COLD AND ULTRACOLD MOLECULES

    NASA Astrophysics Data System (ADS)

    Carr, Lincoln D.; Ye, Jun

    2009-05-01

    öhlich, A Griesmaier, T Pfau, H Saito, Y Kawaguchi and M Ueda High-energy-resolution molecular beams for cold collision studies L P Parazzoli, N Fitch, D S Lobser and H J Lewandowski Collisional effects in the formation of cold guided beams of polar molecules M Motsch, C Sommer, M Zeppenfeld, L D van Buuren, P W H Pinkse and G Rempe Towards sympathetic cooling of large molecules: cold collisions between benzene and rare gas atoms P Barletta, J Tennyson and P F Barker Efficient formation of ground-state ultracold molecules via STIRAP from the continuum at a Feshbach resonance Elena Kuznetsova, Marko Gacesa, Philippe Pellegrini, Susanne F Yelin and Robin Côté Emergent timescales in entangled quantum dynamics of ultracold molecules in optical lattices M L Wall and L D Carr Rotational state resolved photodissociation spectroscopy of translationally and vibrationally cold MgH+ ions: toward rotational cooling of molecular ions K Højbjerre, A K Hansen, P S Skyt, P F Staanum and M Drewsen Collective transverse cavity cooling of a dense molecular beam Thomas Salzburger and Helmut Ritsch A Stark decelerator on a chip Samuel A Meek, Horst Conrad and Gerard Meijer Deceleration of molecules by dipole force potential: a numerical simulation Susumu Kuma and Takamasa Momose Ultracold molecules: vehicles to scalable quantum information processing Kathy-Anne Brickman Soderberg, Nathan Gemelke and Cheng Chin Magnetic field modification of ultracold molecule-molecule collisions T V Tscherbul, Yu V Suleimanov, V Aquilanti and R V Krems Spectroscopy of 39K85Rb triplet excited states using ultracold a 3Σ+ state molecules formed by photoassociation J T Kim, D Wang, E E Eyler, P L Gould and W C Stwalley Pumping vortex into a Bose-Einstein condensate of heteronuclear molecules Z F Xu, R Q Wang and L You Intense atomic and molecular beams via neon buffer-gas cooling David Patterson, Julia Rasmussen and John M Doyle Dynamical properties of dipolar Fermi gases T Sogo, L He, T Miyakawa, S Yi, H Lu