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1

Relationships between ultimate pH and microbial, chemical, and physical characteristics of vacuum-packaged pork loins.  

PubMed

This study evaluated the effect of ultimate pH (pHu) of pork on shelf life based upon microbial growth, drip loss, and oxidative rancidity (2-thiobarbituric acid [TBA] procedure) in vacuum-packaged loins stored at 4 degrees C. Glucose and lactate concentrations of the pork loins were also measured. Thirty-six pork loins (pH = 5.56 to 6.57) were collected at a commercial slaughter facility 1-d postslaughter. All pigs were from the same genetic line. Loins were grouped by pH (group: pH range): A: 5.55 to 5.70, B: 5.71 to 5.85, C: 5.86 to 6.00, D: 6.01 to 6.15, and E: > 6.16. They were analyzed at days 0, 6, 14, 24, and 34. For aerobic plate counts, groups A and B were significantly lower than C through E, while psychrotrophic or Enterobacteriaceae counts of groups A and A through C were significantly lower than groups B through E and D and E, respectively. Lactic acid bacteria counts were not significantly influenced by pHu. Group A had higher glucose concentrations than groups C through E and higher lactate concentrations than groups D through E on most sampling days. Group A had a higher TBA value than group E at days 0 and 34. Group A displayed greater drip loss than groups D and E at day 6 and groups B through D on days 24 and 34. Based on the microbial and drip loss results, a pork loin pHu of 5.8 to 5.9 appears to be optimum to provide a vacuum-packaged shelf life of at least 24 d with minimum drip loss. PMID:18387112

Knox, B L; van Laack, R L J M; Davidson, P M

2008-04-01

2

The effects of early post-mortem pH and ultimate pH on level and amount of destructured zones in cooked cured hams.  

PubMed

Effects of early (1h p.m. and 3h p.m.) and ultimate pH (24h p.m.) on level and amount of destructured zones in cooked cured hams were evaluated. In experiment 1, electrically stimulated (50 V, 14 Hz, 2 x 90s) and non-stimulated carcass halves, both in combination with two cooling procedures (2 degrees C from 30 min p.m. vs. 120 min p.m.) resulted in 1.5-35.2g/kg destructured zones in silversides and 58.4-120.0 g/kg destructured zones in topsides. A high temperature 1h p.m. in silversides (P=0.067) and topsides (P=0.054) was identified as the most important predictor for the defect. In experiment 2, cooked cured hams from topsides selected according to ultimate pH groups (pH<5.5, pH 5.5-5.7, pH>5.7) showed between 12.3 and 61.8 g/kg destructured zones. Ultimate pH was specified as most important, however, statistically still not significant (P=0.135) predictor for the defect. Chemical analysis resulted in low crude ash and high dry matter content as being characteristic for the defect. PMID:20456869

Hugenschmidt, Gabriel; Hadorn, Ruedi; Scheeder, Martin R L; Silacci, Paolo; Scherrer, Daniel; Wenk, Caspar

2010-08-01

3

Effect of Acacia karroo Supplementation on Growth, Ultimate pH, Colour and Cooking Losses of Meat from Indigenous Xhosa Lop-eared Goats  

PubMed Central

The objective of the study was to determine the effect of Acacia karroo supplementation on growth, ultimate pH, colour and cooking losses of meat from indigenous Xhosa lop-eared goats. Eighteen castrated 4-month-old kids were used in the study until slaughter. The kids were subdivided in two treatment groups A. karroo supplemented (AK) and non-supplemented (NS). The supplemented goats were given 200 g per head per d of fresh A. karroo leaves. The kids were slaughtered on d 60 and sample cuttings for meat quality assessment were taken from the Longistimus dorsi muscle. The supplemented kids had higher (p<0.05) growth rates than the non-supplemented ones. The meat from the A. karroo supplemented goats had lower (p<0.05) ultimate pH and cooking loss than the meat from the non-supplemented goats. Acacia karroo supplemented goats produced higher (p<0.05) b* (yellowness) value, but supplementation had no significant effect on L* (lightness) and a* (redness) of the meat. Therefore, A. karroo supplementation improved growth performance and the quality of meat from goats.

Ngambu, S.; Muchenje, V.; Marume, U.

2013-01-01

4

Sequence stratigraphy and hydrocarbon potential of the Phu Khanh Basin offshore central Vietnam, South China Sea  

Microsoft Academic Search

The Phu Khanh Basin offshore central Vietnam is one of the few untested basins on the Vietnam margin of the South China Sea. Analysis of over 1,600 km of multi-channel seismic reflection data indicates that the Phu Khanh Basin follows a typical rift-margin order: faulted basement, synrift sedimentation, a breakup unconformity, and postrift sedimentation. Postrift sedimentation consists of a transgressive

G. H. Lee; J. S. Watkins

1996-01-01

5

Evaluation of Water Hyacinth Diets for Fattening Pigs in Tan Phu Thanh Village  

Microsoft Academic Search

An on- farm trial was carried out in Tan Phu Thanh village, with 30 Yorkshire fattening pigs (15 females and 15 males), with an average initial live weight of 60 kg and final live weight of 110 kg. It included 3 Water hyacinth (WH) diets (1% WH, 3% WH and 5% WH diets in dry matter basis) and 5 small

Seishi Yamasaki; Nguyen Thi; Kim Khang; Nguyen Ngoc; Bao Quyen; Ryozo Takada

6

Structural analysis and identification of PhuS as a heme-degrading enzyme from Pseudomonas aeruginosa.  

PubMed

Bacterial pathogens require iron for proliferation and pathogenesis. Pseudomonas aeruginosa is a prevalent Gram-negative opportunistic human pathogen that takes advantage of immunocompromised hosts and encodes a number of proteins for uptake and utilization of iron. Here we report the crystal structures of PhuS, previously known as the cytoplasmic heme-trafficking protein from P. aeruginosa, in both the apo- and the holo-forms. In comparison to its homologue ChuS from Escherichia coli O157:H7, the heme orientation is rotated 180° across the ?-? axis, which may account for some of the unique functional properties of PhuS. In contrast to previous findings, heme binding does not result in an overall conformational change of PhuS. We employed spectroscopic analysis and CO measurement by gas chromatography to analyze heme degradation, demonstrating that PhuS is capable of degrading heme using ascorbic acid or cytochrome P450 reductase-NADPH as an electron donor and produces five times more CO than ChuS. Addition of catalase slows down but does not stop PhuS-catalyzed heme degradation. Through spectroscopic and mass spectrometry analysis, we identified the enzymatic product of heme degradation to be verdoheme. These data taken together suggest that PhuS is a potent heme-degrading enzyme, in addition to its proposed heme-trafficking function. PMID:24560694

Lee, Michael J Y; Schep, Daniel; McLaughlin, Brian; Kaufmann, Martin; Jia, Zongchao

2014-05-01

7

Implications of river morphology response to Dien Bien Phu fault in NW Vietnam  

NASA Astrophysics Data System (ADS)

In northern Vietnam, most rivers are flowing southeastward sub- or parallel to the valley of Red River and characterized by long but narrow catchments. The Dien Bien Phu fault is associated with the most seismically active zone in Vietnam and situated in the potential eastern boundary of the rotating southeastern Tibetan block. It cuts the Da River, the largest tributary of Red River in northwest Vietnam and has distorted the drainage basin resulting in complex river patterns. To assess the river morphology response to active Dien Bien Phu fault, we use 1/50,000 topographic data and ASTER images to map the precise river courses and digital elevation model data of SRTM to retrieve and analyze the river profiles. From the mapping results, the N-S striking fault results in three conspicuous north-trending river valleys coincided with the different fault segments to facilitate the measurement and reconstruction of the offsets along the fault. Further combining the longitudinal profile analysis we obtain ca. 10 km offsets by deflected river as the largest left-lateral displacement recorded along the active fault. The restored results show the downstream paleochannel of the Da River had been abandoned and becomes two small tributaries in opposite flow directions at present due to differential crustal uplift. Also the present crisscross valley at the junction of the Da River and the fault is resulted from the capture by another river which has been also deflected by the neotectonics. Based on our observations on river response, the Dien Bien Phu fault is a sinistral dominant fault with an uplift occurring in its eastern block. Furthermore the active Dien Bien Phu fault does not cut through the Red River northward indicating the western block of the fault can not be regarded as a single rigid block. There should be possible to find NW-SE trending faults paralleling to Red River to accommodate the deformation of the western block of the fault.

Lai, K.; Chen, Y.; Lam, D.

2004-12-01

8

Implications of river morphology response to Dien Bien Phu fault in NW Vietnam  

NASA Astrophysics Data System (ADS)

In northern Vietnam, most rivers are flowing southeastward sub- or parallel to the valley of Red River and characterized by long but narrow catchments. The Dien Bien Phu fault is associated with the most seismically active zone in Vietnam and situated in the potential eastern boundary of the rotating southeastern Tibetan block. It cuts the Da River, the largest tributary of Red River in northwest Vietnam and has distorted the drainage basin resulting in complex river patterns. To assess the river morphology response to active Dien Bien Phu fault, we use 1/50,000 topographic data and ASTER images to map the precise river courses and digital elevation model data of SRTM to retrieve and analyze the river profiles. From the mapping results, the N-S striking fault results in three conspicuous north-trending river valleys coincided with the different fault segments to facilitate the measurement and reconstruction of the offsets along the fault. Further combining the longitudinal profile analysis we obtain ca. 10 km offsets by deflected river as the largest left-lateral displacement recorded along the active fault. The restored results show the downstream paleochannel of the Da River had been abandoned and becomes two small tributaries in opposite flow directions at present due to differential crustal uplift. Also the present crisscross valley at the junction of the Da River and the fault is resulted from the capture by another river which has been also deflected by the neotectonics. Based on our observations on river response, the Dien Bien Phu fault is a sinistral dominant fault with an uplift occurring in its eastern block. Furthermore the active Dien Bien Phu fault does not cut through the Red River northward indicating the western block of the fault can not be regarded as a single rigid block. There should be possible to find NW-SE trending faults paralleling to Red River to accommodate the deformation of the western block of the fault.

Lai, K.; Chen, Y.; Lam, D.

2007-12-01

9

Crustal contamination of Late Neogene basalts in the Dien Bien Phu Basin, NW Vietnam: Some insights from petrological and geochronological studies  

Microsoft Academic Search

Early Pliocene (Zanclean) basalts in the Dien Bien Phu pull-apart basin in NW Vietnam, associated with the presently sinistral Dien Bien Phu Fault Zone, have been dated by the K–Ar method at 4.4–4.9 and 5.4–5.2Ma. Rapid migration of basaltic magma to the surface in the Dien Bien Phu Fault Zone may be due to Pliocene transtension of the crust in

Ewa Koszowska; Anna Wolska; Witold Zuchiewicz; Nguyen Quoc Cuong; Zoltan Pécskay

2007-01-01

10

Insight of the reactivated Dien Bien Phu fault, northwest Vietnam: Implication of the kinematics in north Indochina  

NASA Astrophysics Data System (ADS)

As one of the most conspicuous fault systems in the Indochina, the NNE-trending Dien Bien Phu fault zone extends over a distance of 150 km from Yunnan, China through the NW Vietnam into Laos and may dextrally displaces the Paleozoic-Triassic granitoids and Song Ma suture, performing a great geological discontinuity. Detailed active fault mapping, compiled from stereographic aerial photos, topographic maps, ASTER satellite imageries, and field reconnaissance, along the Dien Bien Phu fault reveals information about the fault geometry, the magnitude and distribution of displacement along the fault, and the relationship between river offset and activity of fault. The modern Dien Bien Phu fault is complex, including step-overs and branches, and is dominated by left-lateral strike-slip displacement. Numerous multiple offsets along the fault can be detected and reconstructed, and the largest sinistral displacement on the Dien Bien Phu fault is probably ca. 12.5 km. Since sinistral motion is likely to have initiated around 5 Ma, the most reasonable Pliocene to present-day average slip rate on the Dien Bien Phu fault is at an order of 2.5 mm/yr. There are several basins developed along the fault and the strongest evidence for an extensional component of displacement is along the southern part of the fault where the basin developed by a half graben with growing strata. Based on the combined Global Positioning System velocity fields observed from northwest Vietnam and south China, about 2 to 3 mm/yr left-lateral slip is measured across the Dien Bien Phu fault, implying the order of ~10 mm/yr left-lateral slip of the Xianshuihe-Xiaojang fault is transferred southward to Dien Bien Phu fault but with an abrupt decrease in magnitude. Further the western block of Dien Bien Phu fault represents more significant E-W extensional behavior as non-rigid block with internal deformation. Results of this study suggest the modern Dien Bien Phu fault performs as a reactivated fault, yet different slip sense, and acts as an eastern boundary of the crustal deformation in north Indochina. However, the present-day kinematics in north Indochina may be dominated by E-W extension and be accommodated by internal distributed deformation different from the crustal fragment defined by Xianshuihe-Xiaojang fault with a clockwise rotating around the eastern Himalayan syntaxis.

Lai, Kuang-Yin; Chen, Yue-Gau; Lâm, Doãn.

2010-05-01

11

The Role of the Cytoplasmic Heme-binding Protein (PhuS) of Pseudomonas aeruginosa in Intracellular Heme Trafficking and Iron Homeostasis*S?  

PubMed Central

The cytoplasmic heme-binding protein PhuS, encoded within the Fur-regulated Pseudomonas heme utilization (phu) operon, has previously been shown to traffic heme to the iron-regulated heme oxygenase (HO). We further investigate the role of PhuS in heme trafficking to HO on disruption of the phuS and hemO genes in a Pseudomonas aeruginosa siderophore-deficient and wild-type background. Previous studies have shown that deletion of hemO prevents the cells from utilizing heme as the sole source of iron. However, disruption of phuS alone resulted in a slow growth phenotype, consistent with its role as a heme-trafficking protein to HO. Furthermore, in contrast to the hemO and hemO/phuS deletion strains, the phuS knockout prematurely produced pyocyanin in the presence of heme. Western blot analysis of PhuS protein levels in the wild-type strain showed that Fur-regulation of the phu operon could be derepressed in the presence of heme. In addition the premature onset of pyocyanin production requires both heme and a functional HO. Suppression of the phenotype on increasing the external heme concentration suggested that the decreased heme-flux through HO results in premature production of pyocyanin. The premature production of pyocyanin was not due to lower intracellular iron levels as a result of decreased heme flux through HO. However, transcriptional analysis of the phuS mutants indicates that the cells are sensing iron deprivation. The present data suggest that PhuS has a dual function in trafficking heme to HO, and in directly or indirectly sensing and maintaining iron and heme homeostasis.

Kaur, Ajinder P.; Lansky, Ila B.; Wilks, Angela

2009-01-01

12

Induced fit on heme binding to the Pseudomonas aeruginosa cytoplasmic protein (PhuS) drives interaction with heme oxygenase (HemO)  

PubMed Central

Iron, an essential nutrient with limited bioavailability, requires specialized cellular mechanisms for uptake. Although iron uptake into the cytoplasm in the form of heme has been well characterized in many bacteria, the subsequent trafficking is poorly understood. The cytoplasmic heme-binding proteins belong to a structurally related family thought to have evolved as “induced fit” ligand-binding macromolecules. One member, Pseudomonas aeruginosa cytoplasmic protein (PhuS), has previously been shown to be important for delivering heme to the iron regulated heme oxygenase (HemO). Spectroscopic investigations of the holo-PhuS complex revealed a dynamic heme environment with overlapping but distinct heme-binding sites with alternative coordinating heme ligands, His-209 or His-212. In the present work we establish a mechanism for how heme is transferred from PhuS to its partner, HemO. Using surface plasmon resonance and isothermal titration calorimetry, we have discovered that holo-PhuS, but not apo-PhuS, forms a 1:1 complex with HemO. Sedimentation velocity and limited proteolysis experiments suggest that heme binding to PhuS induces a conformational rearrangement that drives the protein interaction with HemO. Hydrodynamic analysis reveals that the holo-PhuS displays a more expanded hydrodynamic envelope compared with apo-PhuS, and we propose that this conformational change drives the interaction with HemO. We further demonstrate that replacement of His-212 by Ala disrupts the interaction of holo-PhuS with HemO; in contrast, the His-209-Ala variant can still complex with HemO, albeit more weakly. Together, the present studies reveal a mechanism that couples a heme-dependent conformational switch in PhuS to protein–protein interaction, the subsequent free energy of which drives heme release to HemO.

O'Neill, Maura J.; Bhakta, Mehul N.; Fleming, Karen G.; Wilks, Angela

2012-01-01

13

StatSoft Inc. 2005 statistic (data analysis software system) version 7.1. www.statsoft.com. lack R.L.J.M. KAUFFMAN ROG. GREASER Mel. 2001 Determinants ultimate pH meat. Proceedings 47th International Congress Meat Science Technology August 26-31 Creco Poland Volume I 22-26.  

EPA Pesticide Factsheets

Did you mean: StatSoft Inc. 2005 statistic (data analysis software system) version 7.1. www.statsoft.com. lack R.L.J.M. KAUFFMAN ROG. GREASER Mel. 2001 Determinants ultimate pH meat. Proceedings 47th International Congress Meat Science Technology August 26-31 Creco Poland Volume I 22-26. ?

14

The Ultimate Flag Games.  

ERIC Educational Resources Information Center

This paper describes six Ultimate Flag Games which offer a change from traditional games and sports that are usually geared toward athletically inclined students. These new games, aimed at middle school through college students, allow for success from the least-skilled through the most athletically talented students. Players are ability grouped…

Angel, Kenny; Sutton, Nancy

15

The Ultimate Fizz  

NSDL National Science Digital Library

Many recipes for elementary science activities suggest making carbon dioxide from baking soda and vinegar; however, they often do not give exact measurements of the ingredients. The author was able to turn this "drawback" into a plus by challenging her fifth-grade students to find the ultimate fizz--i.,e. , "What amount of baking soda added to a set amount of vineagar gives the maximum reaction without having leftover baking soda?" As students investigated this question with enthusiasm, graphing and measurement skills developed in the process.

Heckscher, Mary

2008-12-01

16

Ultimate injuries: a survey.  

PubMed

Injuries sustained while playing Ultimate at six tournaments between 1986 and 1990 were recorded. Thigh muscle strains, ankle ligament sprains and skin abrasions/friction burns were the most frequent injuries. Factors contributing to injury include pitch state, player fitness and preparation, clothing, 'lay-out' technique, tournament organization and squad size. Reducing excessive playing time, improved preparation by the player, sensible use of protective clothing, and care with pitch selection should all lead to a reduction in the number of injuries. PMID:1810621

Marfleet, P

1991-12-01

17

Ultimate Realities: Deterministic and Evolutionary  

ERIC Educational Resources Information Center

References to ultimate reality commonly turn up in the behavioral literature as references to determinism. However, this determinism is often difficult to interpret. There are different kinds of determinisms as well as different kinds of ultimate realities for a behaviorist to consider. To clarify some of the issues involved, the views of ultimate

Moxley, Roy A.

2007-01-01

18

Crustal contamination of Late Neogene basalts in the Dien Bien Phu Basin, NW Vietnam: Some insights from petrological and geochronological studies  

NASA Astrophysics Data System (ADS)

Early Pliocene (Zanclean) basalts in the Dien Bien Phu pull-apart basin in NW Vietnam, associated with the presently sinistral Dien Bien Phu Fault Zone, have been dated by the K-Ar method at 4.4-4.9 and 5.4-5.2 Ma. Rapid migration of basaltic magma to the surface in the Dien Bien Phu Fault Zone may be due to Pliocene transtension of the crust in this region, resulting from asthenospheric upwelling induced by lateral displacement of the mantle. The basalts are moderately phyric ( < 10%) and consist of olivine (hyalosiderite), plagioclase (bytownite-labradorite) and orthopyroxene (bytownite-labradorite) phenocrysts, and a fine-grained crystalline matrix (olivine-hortonolite, plagioclase-labradorite, clinopyroxene-pigeonite and augite, K-feldspar). The presence of Fe-rich olivine and orthopyroxene phenocrysts indicates that the basalts are SiO 2-saturated/oversaturated olivine tholeiites which formed under water-undersaturated conditions. The Dien Bien Phu basalts contain both mantle-derived (pyroxenites, dunites, gabbros) and crustal (sillimanite/mullite + Mg-Fe spinel), wallrock xenoliths, indicative of crustal contamination during the ascent of the basaltic magma. The basalts show selective enrichment in some mobile elements (K, Rb, Sr and Th), a feature considered to be a result of metasomatism. These rocks, classified on the basis of their normative composition as quartz tholeiites, could represent primary olivine tholeiites/basalts, in which the geochemical signatures were modified by the processes of contamination.

Koszowska, Ewa; Wolska, Anna; Zuchiewicz, Witold; Cuong, Nguyen Quoc; Pécskay, Zoltan

2007-01-01

19

Shear wall ultimate drift limits  

SciTech Connect

Drift limits for reinforced-concrete shear walls are investigated by reviewing the open literature for appropriate experimental data. Drift values at ultimate are determined for walls with aspect ratios ranging up to a maximum of 3.53 and undergoing different types of lateral loading (cyclic static, monotonic static, and dynamic). Based on the geometry of actual nuclear power plant structures exclusive of containments and concerns regarding their response during seismic (i.e.,cyclic) loading, data are obtained from pertinent references for which the wall aspect ratio is less than or equal to approximately 1, and for which testing is cyclic in nature (typically displacement controlled). In particular, lateral deflections at ultimate load, and at points in the softening region beyond ultimate for which the load has dropped to 90, 80, 70, 60, and 50 percent of its ultimate value, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of statistics to estimate Probability of Failure for a shear wall structure is illustrated.

Duffey, T.A. [Duffy, (T.A.) Tijeras, NM (United States); Goldman, A. [Goldman, (A.), Sandia, Los Alamos, NM (United States); Farrar, C.R. [Los Alamos National Lab., NM (United States)

1994-04-01

20

Ultimate Cost of Building Walls.  

ERIC Educational Resources Information Center

The need for economic analysis of building walls is discussed, and the factors influencing the ultimate cost of exterior walls are studied. The present worth method is used to analyze three types of exterior non-loadbearing panel or curtain walls. Anticipated costs are expressed in terms of their present value per square foot of wall area. The…

Grimm, Clayford T.; Gross, James G.

21

Quaternary basin formation along the Dien Bien Phu fault zone and its neotectonic implication of northwestern Vietnam  

NASA Astrophysics Data System (ADS)

The Dien Bien Phu (DBP) fault zone is one of the most conspicuous fault systems in the Indochina, extending over a distance of 150 km from Yunnan, China through the NW Vietnam into Laos. Recent Global Positioning system (GPS) data in China yielded that the present clockwise rotation of the southeastern Tibet block geologically corresponds to a region of left-lateral strike-slip faults, such as the Xianshuihe-Xiaojang fault and Dien Bien Phu fault, which appear to have accommodated clockwise rotation; whereas other GPS data from the network of Southeast Asia proposed that Indochina constitutes a stable tectonic block moving approximately east with respect to Eurasia. Although above GPS data show insignificant differential motion along DBP fault, active sinistral slip can be identified by clear geomorphic features, focal solutions and seismicity distribution in a NNE-striking zone parallel to the fault zone. Mapping of surface fault traces along the DBP fault zone using field outcrops, geophysical data, and geomorphologic features recognized by the aerial photos, SRTM, ASTER imageries and derived digital elevation models shows that virtually all active faults are reactivated structures sub-parallel to chronostratigraphic boundary. Along the DBF fault, three larger basins have been developed by different kinematics from north to south. The northern one at Chan Nua is rhomboidal in shape with a dimension of 2.5 km?.5 km, which can be defined as a pull-apart basin resulted by the strike-slip motion of the DBP fault. The fault configuration associated with the central one changes to two parallel sinistral and sinistral-normal faults forming a narrow subsiding weak zone (10 km?.5 km) filled with Quaternary deposits. The southern one is, however, created by that the main DBP fault bends the strike from NNE to NE where branches out a sinistral- normal fault with N-striking controlling a half-graben basin (17 km? km) filled with Quaternary deposits about 200 m in depth above the late Neogene olivine basalt. The late Neogene basalt of age ca. 5 Ma seems being at least displaced 10 km by the branched sinistral-normal fault, giving a rate of ca. 2 mm/yr by left-lateral strike-slip since volcanic eruption. For the southern two basins, normal faulting has been confirmed occurring along their east margin, implying the NW-striking fault systems, i.e. Son La and Song Ma faults, in northwestern Vietnam are active. Although the proposed mechanisms of above-mentioned basins are still tentative, the DBP fault zone is undoubtedly undergoing extensional tectonic environment in rigid Indochina block. Further studies on basin depositional history and age determination are needed for the purpose of establishing the dynamic model of each basin and recognizing the neotectonic behavior of DBP fault.

Lai, K.; Chen, Y.; Chung, L.; Li, P.; Lam, D.

2006-12-01

22

Quaternary sediments in the Dien Bien Phu fault zone, NW Vietnam: a record of young tectonic processes in the light of OSL-SAR dating results  

NASA Astrophysics Data System (ADS)

The Dien Bien Phu fault zone (DBP), orientated NNE to N, is one of the most seismically active zones in Indochina. In NW Vietnam, this zone is 160 km long and 6-10 km wide, cutting sedimentary and metamorphic rocks of the Late Proterozoic, Palaeozoic and Mesozoic age, as well as Palaeozoic and Late Triassic granitoids. Along the DBP relatively small, narrow pull-apart basins occur, the three largest of which (Chan Nua, Lai Chau and Dien Bien Phu) have been studied in detail. All of them are bounded by sinistral and sinistral-normal faults, responsible for offset and deflected drainage, presence of numerous shutter ridges and displaced terraces and alluvial fans. The normal component of motion is testified to by well-preserved triangular facets on fault scarps, highly elevated straths in river watergaps, overhanging tributary valleys, as well as high and uneven river-bed gradients. Our observations indicate a minimum recent sinistral offset ranging from 6-8 to 150 m for Holocene valleys to 1.2-9.75 km for middle-late Pleistocene valleys in different fault segments. The thickness of Quaternary sediments varies from 5-25 m in the Lai Chau area to some 130 m in the Dien Bien Phu Basin. In the Lai Chau Basin, the middle terrace (23 m) alluvia of Nam Na River at Muong Te bridge have been optically stimulated luminescence/single aliquot regenerative dose technique (OSL-SAR) dated at 23-40 to 13 ka. These sediments were normal-faulted by some 11 m after 13 ka, and mantled by vari-coloured slope loams, 8-12 m thick, containing colluvial wedges composed of angular debris. These wedges were probably formed due to at least three palaeoseismic events postdating 6 ka. In the Dien Bien Phu Basin, in turn, alluvium of the upper Holocene terraces has been OSL-SAR dated to 6.5-7 and 1.7-1.0 ka, whereas the younger (sub-recent) terrace sediments give ages of 0.5-0.2 ka. Displaced terraces and alluvial fans allow us to suppose that the sinistral and sinistral-normal faults bounding narrow pull-apart basins in the southern portion of the DBP fault reveal minimum rates of left-lateral strike-slip ranging from 0.6 to 2 mm/year in Holocene and 0.5-3.8 mm/year in Pleistocene times, whereas rates of Holocene uplift tend to attain 1 mm/year north of Lai Chau and 0.4-0.6 mm/year west of Dien Bien Phu. More precise estimations, however, are difficult to obtain due to poor age control of the displaced drainage. Rates of Quaternary strike-slip are comparable with those of the Red River fault; the sense of movement being, however, opposite. Taking into account the presence of two phases of Late Cenozoic strike-slip of contrasting sense of motion, as well as the geometry of the two fault zones, we hypothesize that the Red River and Dien Bien Phu faults are conjugate faults capable of generating relatively strong earthquakes in the future.

Zuchiewicz, Witold; Cuong, Nguyen Quoc; Bluszcz, Andrzej; Michalik, Marek

2004-06-01

23

GPS measurements of horizontal deformation across the Lai Chau-Dien Bien (Dien Bien Phu) fault, in Northwest of Vietnam, 2002-2004  

NASA Astrophysics Data System (ADS)

Global Positioning System (GPS) measurements from Feb. 2002 through Mar. 2004 were used to estimate the recent crustal movement along the Lai Chau - Dien Bien (Dien Bien Phu) fault (LC-DBF) system in the Northwest of Vietnam. Four GPS campaign data were processed to estimate ITRF2000 and local horizontal velocities, as well as extensive and compressive strain rates across the LC-DBF. ITRF2000 velocities are consistent with east-southeastward movement of Sundaland i.e. Indochina. Local velocities did not reveal much left-lateral strike-slip of the fault system and the derived strain rates were insignificantly different from zero at 95% confidence.

Duong, C. C.; Yun, H.-S.; Cho, J.-M.

2006-05-01

24

Morphotectonics of the Dien Bien Phu fault, northwest Vietnam and its implications for present-day kinematics in northern Indochina  

NASA Astrophysics Data System (ADS)

The north- to northeast-trending Dien Bien Phu fault (DBPF) zone is one of the most conspicuous fault systems in Indochina, extending over a distance of 150 km from Yunnan, China through northwest Vietnam into Laos, and dextrally displaces the northwest-trending Song Ma suture, and Mesozoic and Paleozoic strata, acting as a great geological discontinuity. Detailed mapping, compiled from topographic maps, stereographic aerial photos, ASTER satellite imageries, and field reconnaissance discovers new information on the fault geometry, the slip magnitude and distribution along the fault, and the relationship between river-channel offset and fault activity. The geometry of the modern DBPF is complex, consisting of step-overs and strands, and is currently dominated by left-lateral strike-slip displacement. Numerous multiple offsets along the fault are recognized and reconstructed, and the largest sinistral displacement on the DBPF is ca. 12.5 km. Since sinistral motion is likely to have initiated around 5 Ma, the most probable Pliocene to present average slip rate on the DBPF is on the order of 2.5 mm/yr. Based on the combined Global Positioning system velocity fields observed from northwest Vietnam and south China, about 2 to 3 mm/yr left-lateral slip is measured across the DBPF, indicating the left-lateral slip rate of ~10 mm/yr of the Xianshuihe-Xiaojiang fault (XSHF-XJF) has been transferred to DBPF but with an drastic decrease in magnitude. Furthermore, northern Indochina located at the western side of DBPF represents more significant east-west extension, implying the non-rigid block with internal deformation. Results of this study suggest that the modern DBPF zone performs as a reactivated fault, with a different slip sense from its previous phase, and plays a role as an eastern boundary of the crustal deformation in northern Indochina. However, the present-day kinematics in northern Indochina may be dominated by east-west extension and be accommodated by internal distributed deformation different from the crustal fragment defined by XSHF-XJF zone with a clockwise rotation around the eastern Himalayan syntaxis.

Lai, K.; Chen, Y.; Lam, D.

2011-12-01

25

Seeking Ultimates. An Intuitive Guide to Physics  

Microsoft Academic Search

Physics has the reputation of being a difficult and dry subject. Many books have been written in attempts to show that the difficulties are not insurmountable, even for the layman, and to convey some of the fascination it provides for those within it. In Seeking Ultimates Peter Landsberg avoids mathematics, the source of so many difficulties, entirely, and seeks to

Neil Brown

2000-01-01

26

Probing the ultimate limits of plasmonic enhancement.  

PubMed

Metals support surface plasmons at optical wavelengths and have the ability to localize light to subwavelength regions. The field enhancements that occur in these regions set the ultimate limitations on a wide range of nonlinear and quantum optical phenomena. We found that the dominant limiting factor is not the resistive loss of the metal, but rather the intrinsic nonlocality of its dielectric response. A semiclassical model of the electronic response of a metal places strict bounds on the ultimate field enhancement. To demonstrate the accuracy of this model, we studied optical scattering from gold nanoparticles spaced a few angstroms from a gold film. The bounds derived from the models and experiments impose limitations on all nanophotonic systems. PMID:22936772

Ciracì, C; Hill, R T; Mock, J J; Urzhumov, Y; Fernández-Domínguez, A I; Maier, S A; Pendry, J B; Chilkoti, A; Smith, D R

2012-08-31

27

Probing the Ultimate Limits of Plasmonic Enhancement  

PubMed Central

Metals support surface plasmons at optical wavelengths and have the ability to localize light to sub-wavelength regions. The field enhancements that occur in these regions set the ultimate limitations on a wide range of nonlinear and quantum optical phenomena. Here we show that the dominant limiting factor is not the resistive loss of the metal, but the intrinsic nonlocality of its dielectric response. A semi-classical model of the electronic response of a metal places strict bounds on the ultimate field enhancement. We demonstrate the accuracy of this model by studying the optical scattering from gold nanoparticles spaced a few angstroms from a gold film. The bounds derived from the models and experiments impose limitations on all nanophotonic systems.

Ciraci, C.; Hill, R. T.; Mock, J. J.; Urzhumov, Y.; Fernandez-Dominguez, A. I.; Maier, S. A.; Pendry, J. B.; Chilkoti, A.; Smith, D. R.

2013-01-01

28

The Ultimate Analysis of Natural Waters  

Microsoft Academic Search

Although waters have been analyzed for over 2,000 years, no one has yet accomplished a truly complete analysis for the detection and determination of all the ions, the molecules and complex species that must be present. The significance and challenge of the ultimate analysis of waters is discussed.While testifying in a court case in the 1890's, Professor Angstrom swore that

Philip W. West; Roberta Bustin

1972-01-01

29

The ultimate disposition of depleted uranium  

SciTech Connect

Significant amounts of the depleted uranium (DU) created by past uranium enrichment activities have been sold, disposed of commercially, or utilized by defense programs. In recent years, however, the demand for DU has become quite small compared to quantities available, and within the US Department of Energy (DOE) there is concern for any risks and/or cost liabilities that might be associated with the ever-growing inventory of this material. As a result, Martin Marietta Energy Systems, Inc. (Energy Systems), was asked to review options and to develop a comprehensive plan for inventory management and the ultimate disposition of DU accumulated at the gaseous diffusion plants (GDPs). An Energy Systems task team, under the chairmanship of T. R. Lemons, was formed in late 1989 to provide advice and guidance for this task. This report reviews options and recommends actions and objectives in the management of working inventories of partially depleted feed (PDF) materials and for the ultimate disposition of fully depleted uranium (FDU). Actions that should be considered are as follows. (1) Inspect UF{sub 6} cylinders on a semiannual basis. (2) Upgrade cylinder maintenance and storage yards. (3) Convert FDU to U{sub 3}O{sub 8} for long-term storage or disposal. This will include provisions for partial recovery of costs to offset those associated with DU inventory management and the ultimate disposal of FDU. Another recommendation is to drop the term tails'' in favor of depleted uranium'' or DU'' because the tails'' label implies that it is waste.'' 13 refs.

Not Available

1990-12-01

30

Toward the ultimate synthesis/recognition system.  

PubMed Central

This paper predicts speech synthesis, speech recognition, and speaker recognition technology for the year 2001, and it describes the most important research problems to be solved in order to arrive at these ultimate synthesis and recognition systems. The problems for speech synthesis include natural and intelligible voice production, prosody control based on meaning, capability of controlling synthesized voice quality and choosing individual speaking style, multilingual and multidialectal synthesis, choice of application-oriented speaking styles, capability of adding emotion, and synthesis from concepts. The problems for speech recognition include robust recognition against speech variations, adaptation/normalization to variations due to environmental conditions and speakers, automatic knowledge acquisition for acoustic and linguistic modeling, spontaneous speech recognition, naturalness and ease of human-machine interaction, and recognition of emotion. The problems for speaker recognition are similar to those for speech recognition. The research topics related to all these techniques include the use of articulatory and perceptual constraints and evaluation methods for measuring the quality of technology and systems. Images Fig. 3

Furui, S

1995-01-01

31

Two ultimate tests of constrained supersymmetry  

NASA Astrophysics Data System (ADS)

We examine the prospects of using two alternative and complementary ways to explore the regions that are favored by global constraints in two simple unified supersymmetric models: the CMSSM and the NUHM. First, we consider BR ( B s ? ? + ? -), which has recently been for the first time measured by LHCb. In the CMSSM we show that ultimate, but realistic, improvement in the determination of the observable to about 5-10% around the Standard Model value would strongly disfavor the A-funnel region, while not affecting much the other favored regions. Second, we show that all the favored regions of the CMSSM will be, for the most part, sensitive to direct dark matter searches in future one-tonne detectors. A signal at low WIMP mass (? 450 GeV) and low spin-independent cross section would then strongly favor the stau coannihilation region while a signal at higher WIMP mass (~ 800 GeV to ~ 1 .2 TeV) would clearly point to the region where the neutralino is higgsino-like with mass ~ 1 TeV. A nearly complete experimental testing of the CMSSM over multi-TeV ranges of superpartner masses, far beyond the reach of direct SUSY searches at the LHC, can therefore be achievable. In the NUHM, in contrast, similar favored regions exist but a sample study reveals that even a precise determination of BR ( B s ? ? + ? -) would have a much less constraining power on the model, including the A-funnel region. On the other hand, this could allow one to, by detecting in one-tonne detectors a signal for 500 GeV ? m? ? 800 GeV, strongly disfavor the CMSSM.

Kowalska, Kamila; Roszkowski, Leszek; Sessolo, Enrico Maria

2013-06-01

32

Bilabiate Flowers: The Ultimate Response to Bees?  

PubMed Central

Background and Aims Bilabiate flowers have evolved in many lineages of the angiosperms, thus representing a convincing example of parallel evolution. Similar to keel blossoms, they have obviously evolved in order to protect pollen against pollen-collecting bees. Although many examples are known, a comprehensive survey on floral diversity and functional constraints of bilabiate flowers is lacking. Here, the concept is widened and described as a general pattern. Methods The present paper is a conceptional review including personal observations of the authors. To form a survey on the diversity of bilabiate blossoms, a search was made for examples across the angiosperms and these were combined with personal observations collected during the last 25 years, coupled with knowledge from the literature. New functional terms are introduced that are independent of morphological and taxonomic associations. Key Results Bilabiate constructions occur in at least 38 angiosperm families. They are characterized by dorsiventral organization and dorsal pollen transfer. They are most often realised on the level of a single flower, but may also be present in an inflorescence or as part of a so-called ‘walk-around flower’. Interestingly, in functional terms all nototribic blossoms represent bilabiate constructions. The great majority of specialized bee-flowers can thus be included under bilabiate and keel blossoms. The syndrome introduced here, however, also paves the way for the inclusion of larger animals such as birds and bats. The most important evolutionary trends appear to be in the saving of pollen and the precision of its transfer. With special reference to the Lamiales, selected examples of bilabiate flowers are presented and their functional significance is discussed. Conclusions Bilabiate blossoms protect their pollen against pollen-collecting bees and at the same time render their pollination more precisely. The huge diversity of realised forms indicate the high selection pressure towards the bilabiate syndrome. As bees are very inventive, however, bilabiate constructions will not represent the ultimate response to bees.

Westerkamp, Christian; Classen-Bockhoff, Regine

2007-01-01

33

Ultimate Performance Limits and Mission Capabilities of Advanced Ion Thrusters.  

National Technical Information Service (NTIS)

The ultimate performance limits and mission capabilities of a nuclear powered, advanced ion thruster propulsion system were examined. This involves consideration of the ultimate ion thruster capability and performance level, together with power supply out...

A. R. Martin A. Bond R. A. Bond

1988-01-01

34

"Got Disc?" The "Ultimate" Experience in Physical Education  

ERIC Educational Resources Information Center

A quality physical education program is one in which students are exposed to and can participate in a variety of sports and activities. One activity that is increasing in popularity in and outside of physical education is the game of "Ultimate." Opportunities to play Ultimate are increasing rapidly in intramural programs and community and…

Johnson, Tyler G.; Darst, Paul W.; Brusseau, Timothy A.

2006-01-01

35

Dynamics of ultimately short electromagnetic pulses in silicene waveguides  

NASA Astrophysics Data System (ADS)

The propagation of ultimately short discrete electromagnetic pulses, which can be considered as optical solitons, in silicene waveguide layers has been studied. A phenomenological equation is obtained that describes the dynamics of ultimately short light pulses in a system of silicene waveguides. Phenomena observed on varying the width of the primary pulse are analyzed.

Konobeeva, N. N.; Belonenko, M. B.

2013-06-01

36

pH Protocol  

NSDL National Science Digital Library

The purpose of this resource is to measure the pH of water. Students use either a pH meter or pH paper to measure the pH. If using the pH meter, the meter needs to be calibrated with buffer solutions that have pH values of 4, 7, and 10.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2005-06-02

37

INFORMATION THEORY: 'Ultimate PC' Would Be a Hot Little Number.  

PubMed

A physicist has used the laws of thermodynamics, information, relativity, and quantum mechanics to figure out the ultimate physical limits on the speed of a computer. His calculations show that, in principle, a kilogram of matter in a liter-sized container could be an "ultimate laptop" more than a trillion trillion trillion times as powerful as today's fastest supercomputer--if it could be turned into a black hole. PMID:17839510

Seife, C

2000-09-01

38

Centaur Standard Shroud (CSS) static ultimate load structural tests  

NASA Technical Reports Server (NTRS)

A series of tests were conducted on the jettisonable metallic shroud used on the Titan/Centaur launch vehicle to verify its structural capabilities and to evaluate its structural interaction with the Centaur stage. A flight configured shroud and the interfacing Titan/Centaur structural assemblies were subjected to tests consisting of combinations of applied axial and shear loads to design ultimate values, including a set of tests on thermal conditions and two dynamic response tests to verify the analytical stiffness model. The strength capabilities were demonstrated at ultimate (125 percent of design limit) loads. It was also verified that the spring rate of the flight configured shroud-to-Centaur forward structural deflections of the specimen became nonlinear, as expected, above limit load values. This test series qualification program verified that the Titan/Centaur shroud and the Centaur and Titan interface components are qualified structurally at design ultimate loads.

1975-01-01

39

Regions of absolute ultimate boundedness for discrete-time systems.  

NASA Technical Reports Server (NTRS)

This paper considers discrete-time systems of the Lur'e-Postnikov class where the linear part is not asymptotically stable and the nonlinear characteristic satisfies only partially the usual sector condition. Estimates of the resulting finite regions of absolute ultimate boundedness are calculated by means of a quadratic Liapunov function.

Siljak, D. D.; Weissenberger, S.

1972-01-01

40

The Ultimate Strength of Single-Story Frames.  

National Technical Information Service (NTIS)

The ultimate strength of single-story, pinned-base rigid frames subjected to vertical and horizontal loads is solved. Interaction curves between the axial load and the horizontal load are developed for a column L/r = 40. Inelastic behavior and residual st...

J. A. Yura T. V. Galambos

1964-01-01

41

Efficiency of preliminary transmutation of actinides before ultimate storage  

Microsoft Academic Search

The concept of preliminary transmutation of minor actinides before placement to the long-term storage is considered. The purpose of such preliminary transmutation before ultimate storage is to incinerate a part of actinides and to transform another part into new actinides providing low level of radiotoxicity accumulated in the storage. Modes of transmutation in reactors of PWR, CANDU, and Superphenix types

B. R. Bergelson; A. S. Gerasimov; G. V. Kiselev; G. V. Tikhomirov

2004-01-01

42

The Ultimate Sampling Dilemma in Experience-Based Decision Making  

ERIC Educational Resources Information Center

Computer simulations and 2 experiments demonstrate the ultimate sampling dilemma, which constitutes a serious obstacle to inductive inferences in a probabilistic world. Participants were asked to take the role of a manager who is to make purchasing decisions based on positive versus negative feedback about 3 providers in 2 different product…

Fiedler, Klaus

2008-01-01

43

37. ALTERNATE DESIGN, SIMILAR TO THAT ULTIMATELY SELECTED, BUT USING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

37. ALTERNATE DESIGN, SIMILAR TO THAT ULTIMATELY SELECTED, BUT USING STEPPED TOWERS, AND WITH PYLONS CAPPED BY LANTERNS Pen-and-ink drawing by project architect Alfred Eichler, ca. 1934. - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

44

BOOK REVIEW: Seeking Ultimates. An Intuitive Guide to Physics  

Microsoft Academic Search

Physics has the reputation of being a difficult and dry subject. Many books have been written in attempts to show that the difficulties are not insurmountable, even for the layman, and to convey some of the fascination it provides for those within it. In Seeking Ultimates Peter Landsberg avoids mathematics, the source of so many difficulties, entirely, and seeks to

Peter T. Landsberg

2000-01-01

45

Pre-slaughter stress arising from on-farm handling and its interactions with electrical stimulation on tenderness of lambs.  

PubMed

The effect of electrical stimulation of lamb carcasses (n=269) or its absence (n=257) on shear force of m. longissimus thoracis et lumborum (LT) was monitored during ageing in pasture-fed merino lambs (n=526). The lambs were slaughtered on four different days allowing durations of between one to 10 days of recovery from pre-slaughter handling (yarding, weighing and crutching) that affected ultimate pH (pH(u)). The right LT was removed 20-40min post-slaughter, tightly-wrapped in cling film (prevents the muscle cross-section increasing and thus minimising shortening) and rapidly cooled to 15°C to enter rigor mortis and age. At 0, 4, 24 and 72h post-slaughter, pH measurements and samples for shear force measurement were taken. Pre-slaughter handling had a significant negative effect on pH(u) and several days recovery were required for pH(u) to reach values associated with optimal meat quality as reflected by pH(u). Lambs with one and three days recovery (no significant difference between them) had a pH(u)>5.7 in 50% of the muscles and 19.4%>pH(u) 5.8. Whereas, in lambs with 8-10 days recovery (no significant difference between them), only 8% had a pH(u)>5.7 and 3.1%>pH(u) 5.8. Within each slaughter day electrically stimulated lambs were always more tender than non-stimulated lambs. For non-stimulated muscles at 72h, shear force values >40N occurred for 11.2% of the muscles: for electrically stimulated muscles at 72h, shear force values >40N occurred for 1.9% of the muscles. The rates of tenderisation were slower for intermediate pH(u) values resulting in higher shear force values at all ageing durations. With ageing at 72h for intermediate pH(u), non-stimulated muscles (n=38) 17.64% were >40N and for stimulated muscles (n=34), 7.9% were >40N. PMID:22062302

Devine, C E; Lowe, T E; Wells, R W; Edwards, N J; Edwards, J E Hocking; Starbuck, T J; Speck, P A

2006-06-01

46

Landau damping: the mechanics model and its ultimate entropy gain  

NASA Astrophysics Data System (ADS)

Classical mechanics has only been invoked to account for Landau damping in a rather half-hearted way, alongside plasma perturbation theory. In particular this invocation is essential for the study of the saturation, or post-linear (or 'nonlinear') regime of the damping initiated by Dawson and O'Neill. By embracing mechanics wholeheartedly here, with its attendant phase space, one can access results, old and new, cleanly and directly, and with one fewer numerical integration for the post-linear regime. By using a summation technique familiar in semiclassical quantum mechanics (Poisson summation), the one remaining numerical integration can be much improved in accuracy. Also accessible from mechanics is the ultimate entropy gain. Though zero for any finite time (in the absence of coarse graining), the entropy gain is ultimately non-zero (at infinite time the required coarse graining is zero). It is calculated analytically by using the appropriate asymptotics, hitherto not fully exploited.

Hannay, J. H.; Kluge, Michel

2011-02-01

47

Thermally assisted MRAMs: ultimate scalability and logic functionalities  

NASA Astrophysics Data System (ADS)

This paper is focused on thermally assisted magnetic random access memories (TA-MRAMs). It explains how the heating produced by Joule dissipation around the tunnel barrier of magnetic tunnel junctions (MTJs) can be used advantageously to assist writing in MRAMs. The main idea is to apply a heating pulse to the junction simultaneously with a magnetic field (field-induced thermally assisted (TA) switching). Since the heating current also provides a spin-transfer torque (current-induced TA switching), the magnetic field lines can be removed to increase the storage density of TA-MRAMs. Ultimately, thermally induced anisotropy reorientation (TIAR)-assisted spin-transfer torque switching can be used in MTJs with perpendicular magnetic anisotropy to obtain ultimate downsize scalability with reduced power consumption. TA writing allows extending the downsize scalability of MRAMs as it does in hard disk drive technology, but it also allows introducing new functionalities particularly useful for security applications (Match-in-Place™ technology).

Prejbeanu, I. L.; Bandiera, S.; Alvarez-Hérault, J.; Sousa, R. C.; Dieny, B.; Nozières, J.-P.

2013-02-01

48

Shear wall ultimate drift limits for PRA applications  

SciTech Connect

Drift limits for reinforced concrete shear walls are investigated by reviewing the technical literature for appropriate experimental data. Based on the geometry of actual nuclear power plant structures (exclusive of containments) and concerns regarding their response during seismic loading, data are obtained from pertinent references where the wall aspect ratio is less than or equal to approximately 1, and for which the loading is cyclic. Lateral deflections at ultimate load, and at points in the softening region beyond ultimate, are obtained and converted to drift information. The statistical nature of the data is also investigated. These data are shown to be lognormally distributed, and an analysis of variance is performed. The use of these statistics to estimate Probability of Failure for a shear wall structure is illustrated.

Duffey, T.A. [New Mexico Highlands Univ., Las Vegas, NM (United States); Farrar, C.R.; Goldman, A. [Los Alamos National Lab., NM (United States)

1995-03-01

49

On the ultimate x-ray detector for angiography  

Microsoft Academic Search

The purpose of our research is to describe the ultimate X-ray detector for angiography. Angiography is a well established X-ray imaging technique for the examination of blood vessels. Contrast agent is injected followed by X-ray exposures and possible obstructions in the blood vessels can be visualized. Standard angiography primarily inspects for possible occlusions and views the vessels as rigid pipes.

Cornelis H. Slump; Joost A. Kauffman; M. J. Flynn

2005-01-01

50

Ultimate low loss of hollow-core photonic crystal fibres  

Microsoft Academic Search

Hollow-core photonic crystal fibres have excited interest as potential ultra-low loss telecommunications fibres because light propagates mainly in air instead of solid glass. We propose that the ultimate limit to the attenuation of such fibres is determined by surface roughness due to frozenin capillary waves. This is confirmed by measurements of the surface roughness in a HC-PCF, the angular distribution

P. J. Roberts; F. Couny; H. Sabert; B. J. Mangan; D. P. Williams; L. Farr; M. W. Mason; A. Tomlinson; T. A. Birks; J. C. Knight; P. St. J. Russell

2005-01-01

51

Silicon wafer-based tandem cells: The ultimate photovoltaic solution?  

NASA Astrophysics Data System (ADS)

Recent large price reductions with wafer-based cells have increased the difficulty of dislodging silicon solar cell technology from its dominant market position. With market leaders expected to be manufacturing modules above 16% efficiency at 0.36/Watt by 2017, even the cost per unit area (60-70/m2) will be difficult for any thin-film photovoltaic technology to significantly undercut. This may make dislodgement likely only by appreciably higher energy conversion efficiency approaches. A silicon wafer-based cell able to capitalize on on-going cost reductions within the mainstream industry, but with an appreciably higher than present efficiency, might therefore provide the ultimate PV solution. With average selling prices of 156 mm quasi-square monocrystalline Si photovoltaic wafers recently approaching 1 (per wafer), wafers now provide clean, low cost templates for overgrowth of thin, wider bandgap high performance cells, nearly doubling silicon's ultimate efficiency potential. The range of possible Si-based tandem approaches is reviewed together with recent results and ultimate prospects.

Green, Martin A.

2014-03-01

52

75 FR 60133 - Agency Information Collection Activities: Declaration of Ultimate Consignee That Articles Were...  

Federal Register 2010, 2011, 2012, 2013

...Declaration of Ultimate Consignee That Articles Were Exported for Temporary Scientific...Declaration of Ultimate Consignee That Articles Were Exported for Temporary Scientific...Declaration of Ultimate Consignee That Articles Were Exported for Temporary...

2010-09-29

53

78 FR 69101 - Agency Information Collection Activities: Declaration of the Ultimate Consignee That Articles...  

Federal Register 2010, 2011, 2012, 2013

...Declaration of the Ultimate Consignee That Articles Were Exported for Temporary Scientific...Declaration of the Ultimate Consignee that Articles were Exported for Temporary Scientific...Declaration of the Ultimate Consignee that Articles were Exported for Temporary...

2013-11-18

54

75 FR 76746 - Agency Information Collection Activities: Declaration of Ultimate Consignee That Articles Were...  

Federal Register 2010, 2011, 2012, 2013

...Declaration of Ultimate Consignee That Articles Were Exported for Temporary Scientific...Declaration of Ultimate Consignee That Articles Were Exported for Temporary Scientific...Declaration of Ultimate Consignee That Articles Were Exported for Temporary...

2010-12-09

55

Understanding pH  

NSDL National Science Digital Library

The first site related to pH is from the Horiba corporate Web site entitled the Story of pH (1). Visitors can learn what pH is and how it's measured, explore various facts about pH, and read several anecdotes such as "Is the Rain in Our Cities Acidic." The site contains simple text, attractive graphics, and a well-designed layout making it fun and easy for anyone to explore. The second site from the Miami Museum of Science is called the pH Factor (2) kids activity page. This interactive and extensive site contains lessons on testing items for pH, tasting acids and bases, an interactive meter to find the pH of common household items, and much more. Next, is the pH and Water Quality (3) page, which is part of the State of Kentucky Division of Water Web site. The site provides a table of the effects of pH on fish and aquatic life and gives a short description of the most significant environmental impacts of pH. Trout for example, can tolerate a pH range between 4.1 and 9.5 while Mosquito larvae can survive within the 3.3 and 4.7 range. The fourth site from Gardengate Magazine.com is entitled More Soil Stuff: Soil pH (4). Described is the pH range of most soil types, requirements of certain plants, how to test soil for pH, and how to adjust it using sulfur and limestone. Seaworld.org maintains the Understanding the pH Cycle within the Aquarium (5) lesson plan site. The stated objective of the activity is to have students define pH, explain how it affects a tank's water quality, and test the pH level in a classroom aquarium. Although an aquarium is obviously needed, the activity offers a unique and fun way for kids to learn about this basic chemistry concept. About.com offers the next site, which is an interactive pH calculator called pH (6). Users simply enter a pH to get the concentration of Hydrogen ions or, conversely, the Hydrogen ion concentration to get the pH. Another tool to learn about pH and Hydrogen ions is called Acids and Alkalis--the pH Scale (7). Provided by Purchon.com, the interactive pH scale illustrates how the ion concentration changes with pH, common acids associated with each, and whether it is a weak or strong acid or alkali. The last site maintained by the National Park Service is called Acid Rain Lesson Plan: Activity 1 The pH Scale (8). Kids will be able to describe the pH scale and its components, explain why a pH measurement must be accurate, and explain why small changes in pH are important. Everything needed to complete the activity is provided, including a materials list, complete instructions, thinking questions, as well as links for further information.

Brieske, Joel A.

56

The ultimate quantum limits on the accuracy of measurements  

NASA Technical Reports Server (NTRS)

A quantum generalization of rate-distortion theory from standard communication and information theory is developed for application to determining the ultimate performance limit of measurement systems in physics. For the estimation of a real or a phase parameter, it is shown that the root-mean-square error obtained in a measurement with a single-mode photon level N cannot do better than approximately N exp -1, while approximately exp(-N) may be obtained for multi-mode fields with the same photon level N. Possible ways to achieve the remarkable exponential performance are indicated.

Yuen, Horace P.

1992-01-01

57

The ultimate challenge: prove B. F. Skinner wrong.  

PubMed

For much of his career, B. F. Skinner displayed the optimism that is often attributed to behaviorists. With time, however, he became less and less sanguine about the power of behavior science to solve the major problems facing humanity. Near the end of his life he concluded that a fair consideration of principles revealed by the scientific analysis of behavior leads to pessimism about our species. In this article I discuss the case for Skinner's pessimism and suggest that the ultimate challenge for behavior analysts today is to prove Skinner wrong. PMID:22478494

Chance, Paul

2007-01-01

58

Design and application of a cusum quality control chart suitable for monitoring effects on ultimate muscle pH  

Microsoft Academic Search

The cumulative sum, or cusum, chart is introduced for on?farm monitoring of meat quality traits. The average time over which production is satisfactory or in control (average run length) is defined for the cusum chart and the calculation of this statistic discussed.Data from 9958 Angus and Hereford steers slaughtered at Manawatu Beef Packers (AFFCO) between February 1993 and February 1994

A. B. Pleasants; D. G. McCall; G. W. Sheath

1998-01-01

59

What is the Ultimate Goal in Acid-Base Regulation?  

ERIC Educational Resources Information Center

It is common to see chapters on acid-base physiology state that the goal of acid-base regulatory mechanisms is to maintain the pH of arterial plasma and not arterial PCO [subscript 2] (Pa[subscript CO[subscript 2

Balakrishnan, Selvakumar; Gopalakrishnan, Maya; Alagesan, Murali; Prakash, E. Sankaranarayanan

2007-01-01

60

The protection of bovine skeletal myofibrils from proteolytic damage post mortem by small heat shock proteins.  

PubMed

This study aimed to determine how small heat shock proteins (sHSPs) protect myofibrillar proteins from ?-calpain degradation during ageing. Immunoprecipitation experiments with M. longissimus dorsi (LD) from Angus heifers (n=14) examined the interaction between ??-crystallin, desmin, titin, HSP20, HSP27 and ?-calpain. Results showed that ??-crystallin associated with desmin, titin, HSP20, HSP27 and ?-calpain. Exogenous ??-crystallin reduced desmin and titin degradations in myofibrillar extracts and attenuated ?-calpain activity. In a second experiment, bull LD (n=94) were aged at -1.5°C for up to 28days post mortem. ?-Calpain autolysed faster in high ultimate pH (pHu) meat (pHu?6.2) and this was concomitant with the more rapid degradation of titin and filamin in this pHu group. Desmin stability in intermediate pHu meat (pHu 5.8 to 6.19) may be due to the protection of myofibril-bound sHSPs combined with the competitive inhibition of ?-calpain by sHSPs. PMID:24769876

Lomiwes, D; Hurst, S M; Dobbie, P; Frost, D A; Hurst, R D; Young, O A; Farouk, M M

2014-08-01

61

The Displacement Perspective During Ultimate Failure of Composite Laminates  

NASA Astrophysics Data System (ADS)

This paper deals with the studies on the state of displacement of symmetric and anti-symmetric angle-ply and cross-ply laminated composite plates during its ultimate failure, subjected to transverse static load. First-order shear deformation theory (FSDT) is employed in conjunction with the finite element approach using eight-noded quadratic isoparametric element. The free vibration analyses of isotropic and laminated composite plates are carried out to ensure the overall validity of the present finite element formulation. The mid surface of the laminate is considered as the reference plane. The principal material directions in different laminae are oriented to produce a laminated structural element capable of resisting loads in several directions. The stiffness of a composite laminate is obtained from the properties of the constituent laminae. The affected stiffness of the failed lamina is discarded completely after the failure of weakest ply. The rigidity matrix of the laminate with remaining laminae is re-established. The re-evaluation process continues until the laminate fails completely. To investigate the displacement behaviour of laminates during the ultimate failure, parametric studies are carried out for different cases by varying the stacking sequences, fiber orientations, layer thicknesses, aspect ratios and the number of layers in the laminate. The comparison of results in terms of non-dimensional natural frequencies and ply-by-ply failure analyses obtained from the present investigation are made with those available in the reported literature.

Pal, P.; Bhar, A.

2013-04-01

62

What is the Ultimate Goal in Acid-base Regulation?  

NSDL National Science Digital Library

Chapters on acid-base physiology often state that the goal of acid-base regulatory mechanisms is to maintain the pH of arterial plasma and not arterial PCO2 or plasma HCO3. A hypothetical situation in which the PaCO2 of arterial plasma is 80 mmHg and the plasma HCO3 concentration is 48 mM is presented and analyzed to get over this misconception.

Selvakumar Balakrishnan (Postgraduate Medical Education and Research Department of Physiology, Jawaharlal Institute); Maya Gopalakrishnan (Postgraduate Medical Education and Research Department of Physiology, Jawaharlal Institute); Murali Alagesan (Asian Institute of Medicine, Science, and Technology, School of Medicine Faculty of Medical and Health Sciences,); Dr. E. Sankaranarayanan Prakash (Asian Institute of Medicine, Science, and Technology School of Medicine Faculty of Medical and Health Sciences)

2007-03-01

63

Approaching ultimate resolution for soft x-ray spectrometers.  

PubMed

We explore the potential performance of soft x-ray spectrometers based on the use of varied-line-spacing spherical diffraction gratings (VLS-SG). The quantitative assessment is based on an optimization procedure to obtain both negligible optical aberrations at full illumination of the grating and a quasi linear focal curve. It involves high-order optical aberration cancellation to calculate the focal curves. We also examine the validity of small divergence closed-form formulas describing the light path function. Optimizing the optical and geometric parameters gives an ultimate resolving power, at 930 eV, of between 10,800 for a 3 m long instrument and 34,000 for an 11 m spectrometer according to the Rayleigh criterion. Typical fabrication tolerances would scale these values down by about 10%. The findings are validated by ray-tracing simulations. PMID:22781243

Chiuzb?ian, Sorin G; Hague, Coryn F; Lüning, Jan

2012-07-10

64

pH Game  

NSDL National Science Digital Library

The purpose of this resource is to teach students about the acidity levels of liquids and other substances around their school so they understand what pH levels tell us about the environment. Students will create mixtures of water samples, soil samples, plants and other natural materials to better understand the importance of pH levels.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

65

Exercise and Pulmonary Hypertension (PH)  

MedlinePLUS

... International PH News and Projects Let Me Breathe Music Video PATIENTS Patients Newly Diagnosed Request an Envelope ... International PH News and Projects Let Me Breathe Music Video Help spread PH awareness and share PH ...

66

Future Synchrotron Light Sources Based on Ultimate Storage Rings  

SciTech Connect

The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving an ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend achromatic cell, we have made significant progress with the design of PEP-X, a USR that would inhabit the decommissioned PEP-II tunnel at SLAC. The enlargement of the dynamic aperture is largely a result of the cancellations of the 4th-order resonances in the 3rd-order achromats and the effective use of lattice optimization programs. In this paper, we will show those cancellations of the 4th-order resonances using an analytical approach based on the exponential Lie operators and the Poisson brackets. Wherever possible, our analytical results will be compared with their numerical counterparts. Using the derived formulae, we will construct 4th-order geometric achromats and use them as modules for the lattice of the PEP-X USR, noting that only geometric terms are canceled to the 4th order.

Cai, Yunhai; /SLAC

2012-04-09

67

Collagen cross-linking and ultimate tensile strength in dentin.  

PubMed

Several studies have indicated differences in bond strength of dental materials to crown and root dentin. To investigate the potential differences in matrix properties between these locations, we analyzed upper root and crown dentin in human third molars for ultimate tensile strength and collagen biochemistry. In both locations, tensile strength tested perpendicular to the direction of dentinal tubules (undemineralized crown = 140.4 +/- 48.6/root = 95.9 +/- 26.1; demineralized crown = 16.6 +/- 6.3/root = 29.0 +/- 12.4) was greater than that tested parallel to the tubular direction (undemineralized crown = 73.1 +/- 21.2/root = 63.2 +/- 22.6; demineralized crown = 9.0 +/- 3.9/root = 16.2 +/- 8.0). The demineralized specimens showed significantly greater tensile strength in root than in crown. Although the collagen content was comparable in both locations, two major collagen cross-links, dehydrodihydroxylysinonorleucine/its ketoamine and pyridinoline, were significantly higher in the root (by ~ 30 and ~ 55%, respectively) when compared with those in the crown. These results indicate that the profile of collagen cross-linking varies as a function of anatomical location in dentin and that the difference may partly explain the site-specific tensile strength. PMID:15381724

Miguez, P A; Pereira, P N R; Atsawasuwan, P; Yamauchi, M

2004-10-01

68

On the ultimate x-ray detector for angiography  

NASA Astrophysics Data System (ADS)

The purpose of our research is to describe the ultimate X-ray detector for angiography. Angiography is a well established X-ray imaging technique for the examination of blood vessels. Contrast agent is injected followed by X-ray exposures and possible obstructions in the blood vessels can be visualized. Standard angiography primarily inspects for possible occlusions and views the vessels as rigid pipes. However, due to the beating heart the flow in arteries is pulsatile. Healthy arteries are not rigid tubes but adapt to various pressure and flow conditions. Our interest is in the (small) response of the artery on the pulse flow. If the arteries responses elastically on the pulse flow, we can expect that it is still healthy. So the detection of artery diameter variations is of interest for the detection of atherosclerosis in an early stage. In this contribution we specify and test a model X-ray detector for its abilities to record the responses of arteries on pulsatile propagating flow distributions. Under normal physiological conditions vessels respond with a temporal increase in arterial internal cross-sectional area of order 10%. This pulse flow propagates along the arteries in response of the left ventricle ejections. We show results of the detection of simulated vessel distensabilities for the model detector and discuss salient parameters features.

Slump, Cornelis H.; Kauffman, Joost A.

2005-04-01

69

Histologic remission: the ultimate therapeutic goal in ulcerative colitis?  

PubMed

Ulcerative colitis (UC) is a disease of the mucosal layer, and activity of the disease is assumed to be related to mucosal appearance. Mucosal healing has emerged as a major therapeutic goal in UC. Whether mucosal healing should be the ultimate therapeutic goal in these patients is unknown. Even when endoscopy suggests mucosal healing, evidence of histologic activity has been observed. Histologic healing requires complete recovery of the colonic mucosa, with absence of inflammation or structural changes. Histologic improvements have been linked with improved clinical outcomes, such as a reduced risk of relapse and need for surgery/hospitalization and a reduced risk of developing cancer. Hence, there is a rationale for aiming for histologic remission in UC. Numerous methods of classification of histologic activity in UC have been proposed, although only some of these are widely used. We review the current definitions of histologic remission, the range of scoring systems most commonly used, and the evidence of histologic improvement that is available from the latest therapies for UC. We also highlight questions that will require careful consideration if histologic remission is to become more widely used as an end point in clinical trials and a treatment goal in clinical practice. PMID:23911875

Peyrin-Biroulet, Laurent; Bressenot, Aude; Kampman, Wendy

2014-06-01

70

The development of high cooling power and low ultimate temperature superfluid Stirling refrigerators  

NASA Astrophysics Data System (ADS)

The superfluid Stirling refrigerator (SSR) is a recuperative Stirling cycle refrigerator which provides cooling to below 2 K by using a liquid 3He-4He mixture as the working fluid. In 1990, Kotsubo and Swift demonstrated the first SSR, and by 1995, Brisson and Swift had developed an experimental prototype capable of reaching a low temperature of 296 mK. The goal of this thesis was to improve these capabilities by developing a better understanding of the SSR and building SSR's with higher cooling powers and lower ultimate temperatures. This thesis contains four main parts. In the first part, a numerical analysis demonstrates that the optimal design and ultimate performance of a recuperative Stirling refrigerator is fundamentally different from that of a standard regenerative Stirling refrigerator due to a mass flow imbalance within the recuperator. The analysis also shows that high efficiency recuperators remain a key to SSR performance. Due to a quantum effect called Kapitza resistance, the only realistic and economical method of creating higher efficiency recuperators for use with an SSR is to construct the heat exchangers from very thin (12 ?m - 25 ?m thick) plastic films. The second part of this thesis involves the design and construction of these recuperators. This research resulted in Kapton heat exchangers which are leaktight to superfluid helium and capable of surviving repeated thermal cycling. In the third part of this thesis, two different single stage SSR's are operated to test whether the plastic recuperators would actually improve SSR performance. Operating from a high temperature of 1.0 K and with 1.5% and 3.0% 3He-4He mixtures, these SSR's achieved a low temperature of 291 mK and delivered net cooling powers of 3705 ?W at 750 mK, 977 ?W at 500 mK, and 409 ?W at 400 mK. Finally, this thesis describes the operation of three versions of a two stage SSR. Unfortunately, due to experimental difficulties, the merits of a two stage SSR were not demonstrated and further work is still required. However, despite these difficulties, one of the two stage SSR's was able to reach an ultimate low temperature of 248 mK from a high temperature of 1.03 K. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Patel, Ashok B.

71

Predicted ultimate capacity of laterally loaded piles in clay using support vector machine  

Microsoft Academic Search

The determination of ultimate capacity of laterally loaded pile in clay is a key parameter for designing the laterally loaded pile. The available methods for determination of ultimate resistance of pile in clay are not reliable. This study investigates the potential of a support vector machine (SVM)-based approach to predict the ultimate capacity of laterally loaded pile in clay. The

Pijush Samui

2008-01-01

72

Ph.D. shortage  

NASA Astrophysics Data System (ADS)

The late 1990s will see a shortage of Ph.D. graduates, according to the Association of American Universities, Washington, D.C. AAU's new comprehensive study, “The Ph.D. Shortage: The Federal Role,” reports that competition for new Ph.D.s is already intense and can only intensify because demand is greater than supply in both academic and nonacademic markets.Doctoral education plays an increasingly important role in U.S. research and development programs. Students have a pivotal part in doing research and enriching it with new ideas. The AAU report says that graduate students are “major determinants of the creativity and productivity of U.S. academic research, the source of more than 50% of the nation's basic research.’ The market for doctoral education extends beyond the university. In 1985, about 43% of all Ph.D.s employed in this country were working outside higher education; the demand for doctorate recipients in nonacademic sectors continues to grow.

73

BOOK REVIEW: Seeking Ultimates. An Intuitive Guide to Physics  

NASA Astrophysics Data System (ADS)

Physics has the reputation of being a difficult and dry subject. Many books have been written in attempts to show that the difficulties are not insurmountable, even for the layman, and to convey some of the fascination it provides for those within it. In Seeking Ultimates Peter Landsberg avoids mathematics, the source of so many difficulties, entirely, and seeks to make physics comprehensible by what he terms intuition. He also emphasizes that there is almost no part of science that is completely understood; there are always areas of incompleteness and uncertainty, capable of providing exciting new results, and examples of this are highlighted throughout the book. After an introduction Landsberg starts with macroscopic phenomena for ease of understanding, though one might question whether the chosen topic of thermodynamics is ever going to be easy. Next he looks at microscopic effects, from atomic structure to the fundamental particles of the standard model and their interactions. There follow chapters on time and entropy, on chaos theory, on quantum mechanics and then cosmology. The final chapters look at physical constants (including the anthropic principle), whether physics has room for a creator God (the conclusion is that this is not the province of science), and some thoughts on science as a human activity. The chosen topics are those which have been important in the late twentieth century and remain important. Each chapter cites an eminent scientist as a `hero', though little is made of this. There are occasional historical notes, set in boxes, and a few short poems to leaven the text. What the book achieves is difficult to assess. Removing mathematics and adding a glossary of technical terms do not necessarily allow non-scientists to enjoy the text, as the publisher's note on the back cover suggests. The concepts can baffle the layman even more than the mathematics, and one of the most difficult of all physical concepts permeates so much of this book: entropy. It is physicists who can benefit most from discarding mathematics and seeking intuitive understanding. It is often too easy to put the numbers into a formula, with little real comprehension of the underlying physics. For layman or physicist the book is hard work. It is not a volume to be read from cover to cover; each section needs to be considered and digested, with frequent turning backwards (or sometimes forwards) to other pages. Even then the outcome may leave questions that can only be answered by access to an academic library to look up some of the copious references to original papers (which, of course, do not eschew mathematics or make concessions to conceptual difficulties). Unfortunately the book is marred by an impression of haste and lack of care, leading to errors that should not have reached the final print. For example, a graph of increase of population with generation number is shown as and stated to be a straight line. It should be exponential. This sort of thing undermines confidence in the whole text. High temperature superconductivity may have a revolutionary effect on electrical machines in the future, but for the time being magnets for magnetic resonance imaging machines and the like still use the old superconductors. Amusing anecdotes make for interesting reading, but the one about Faraday is garbled: he had nothing to do with frogs' legs (that was Galvani), and the quip about taxing electricity one day, if not apocryphal, was made either to Peel or to Gladstone, not to the King. In at least one case a topic mentioned in the index and glossary does not appear on the stated page in the text, apparently having been cut out at a late stage. Personally I did not find the book satisfying, but others will differ. Especially when dealing with intuitive appreciation, what is straightforward to one person may be utterly opaque to another. Making physics comprehensible and conveying its fascination is a daunting and often thankless task, but a very necessary one. The more it is attempted by those with a command of the subject, the more likely i

Brown, Neil

2000-05-01

74

17-4 PH and 15-5 PH  

NASA Technical Reports Server (NTRS)

17-4 PH and 15-5 PH are extremely useful and versatile precipitation-hardening stainless steels. Armco 17-4 PH is well suited for the magnetic particle inspection requirements of Aerospace Material Specification. Armco 15-5 PH and 17-4 PH are produced in billet, plate, bar, and wire. Also, 15-5 PH is able to meet the stringent mechanical properties required in the aerospace and nuclear industries. Both products are easy to heat treat and machine, making them very useful in many applications.

Johnson, Howard T.

1995-01-01

75

A New Ultimate Strength Model of Notched Composite Laminates — Including the Effects of Matrix Failure  

Microsoft Academic Search

A new ultimate strength model is developed to predict the final failure, with the influence of matrix failure, of notched cross-ply laminates. The present model is based on the estimation of the local stresses and the redistribution of the local stresses in the critical damage zones around the notches. The new ultimate strength model can be stated as: when the

C. J. Liu; A. H. J. Nijhof; L. J. Ernst; R. Marissen

2010-01-01

76

Ultimate strength analyses of the Watts Bar, Maine Yankee, and Bellefonte containments  

Microsoft Academic Search

As part of Sandia National Laboratories' Severe Accident Sequence Analysis (SASA) Program, structural analyses of the Watts Bar, Maine Yankee, and Bellefonte containment structures were performed with the obtective of obtaining realistic estimates of their ultimate static pressure capacities. The Watts Bar investigation included analyses of the containment shell, equipment hatch, anchorage systems, and personnel lock. The ultimate pressure capability

1984-01-01

77

Ultimate performance of infrared photodetectors and figure of merit of detector material  

Microsoft Academic Search

A general model describing the ultimate performance of infrared photodetectors arising from fundamental properties of a semiconductor material is presented. The model is applicable to a wide variety of infrared photodetectors and materials. It was shown that the ultimate performance of any type of infrared photodetectors is proportional to (?\\/G)12, where ? is the absorption coefficient and G is the

J. Piotrowski; W. Gawron

1997-01-01

78

Ultimate flexibility  

SciTech Connect

As a result of massive restructuring and streamlining since the privatization of British Gas in 1986, the company runs one of the biggest integrated energy networks in the world, from the exploration for new reserves, through transmission and power generation, to t he delivery of gas to homes and businesses in Great Britain and, increasingly, overseas. Nevertheless, despite shedding 10,000 employees, British Gas has lost, and continues to lose, its share of the local non-domestic supply market. Because of fierce competition, the company`s hold on this British sector dropped from 50 to 40 percent in 1994 alone. Further, the company is facing tough competition fro other developers on the international scene. But the company has been highly successful in developing gas exploration and production initiatives, notably through exploration initiatives in Tunisia, the United ARab Emirates, and in the former Soviet Union.

O`Sullivan, D.

1995-09-01

79

Ultimate Strength of Ship Hull Girders under Moment, Shear and Torque.  

National Technical Information Service (NTIS)

A method was developed to analyze the behavior and ultimate strength of longitudinally stiffened ship hull girder segments of rectangular single-cell cross section, subjected to bending, shear and torsion. Principal features: (1) Enforcement of compatibil...

A. Ostapenko A. Vaucher

1980-01-01

80

METHODS/MATERIALS MATRIX OF ULTIMATE DISPOSAL TECHNIQUES FOR SPILLED HAZARDOUS MATERIALS  

EPA Science Inventory

A study was undertaken to evaluate conventional and novel methods for the ultimate disposal of spilled or released hazardous substances. Disposal methods studied include incineration, pyrolysis, landfilling, fixation, biological treatment, and chemical treatment. Applications of ...

81

78 FR 72972 - Application of Ultimate JETCHARTERS, LLC for Commuter Air Carrier Authority  

Federal Register 2010, 2011, 2012, 2013

...SUMMARY: The Department of Transportation is directing all interested persons to show cause why it should not issue an order finding Ultimate JETCHARTERS, LLC, fit, willing, and able, and awarding it commuter air...

2013-12-04

82

Trends in the ultimate breakdown strength of high dielectric-constant materials  

Microsoft Academic Search

The ultimate breakdown strength Ebd of a dielectric material is found to decrease as the dielectric-constant k increases. A thermochemical description of the ultimate breakdown strength of high-k dielectrics suggests that Ebd should reduce approximately as (k)-12\\/ over a wide range of dielectric materials while the field-acceleration parameter ? should increase in similar but inverse manner. New time-dependent dielectric breakdown

Joe W. McPherson; Jinyoung Kim; Ajit Shanware; Homi Mogul; John Rodriguez

2003-01-01

83

The pH Game.  

ERIC Educational Resources Information Center

Describes a game that can be used to teach students about the acidity of liquids and substances around their school and enable them to understand what pH levels tell us about the environment. Students collect samples and measure the pH of water, soil, plants, and other natural material. (DDR)

Chemecology, 1996

1996-01-01

84

Coping with PH over the Long Term  

MedlinePLUS

... International PH News and Projects Let Me Breathe Music Video PATIENTS Patients Newly Diagnosed Request an Envelope ... International PH News and Projects Let Me Breathe Music Video Help spread PH awareness and share PH ...

85

Universal limiter for transient interpolation modeling of the advective transport equations: The ULTIMATE conservative difference scheme  

NASA Technical Reports Server (NTRS)

A fresh approach is taken to the embarrassingly difficult problem of adequately modeling simple pure advection. An explicit conservative control-volume formation makes use of a universal limiter for transient interpolation modeling of the advective transport equations. This ULTIMATE conservative difference scheme is applied to unsteady, one-dimensional scalar pure advection at constant velocity, using three critical test profiles: an isolated sine-squared wave, a discontinuous step, and a semi-ellipse. The goal, of course, is to devise a single robust scheme which achieves sharp monotonic resolution of the step without corrupting the other profiles. The semi-ellipse is particularly challenging because of its combination of sudden and gradual changes in gradient. The ULTIMATE strategy can be applied to explicit conservation schemes of any order of accuracy. Second-order schemes are unsatisfactory, showing steepening and clipping typical of currently popular so-called high resolution shock-capturing of TVD schemes. The ULTIMATE third-order upwind scheme is highly satisfactory for most flows of practical importance. Higher order methods give predictably better step resolution, although even-order schemes generate a (monotonic) waviness in the difficult semi-ellipse simulation. Little is to be gained above ULTIMATE fifth-order upwinding which gives results close to the ultimate for which one might hope.

Leonard, B. P.

1988-01-01

86

26 CFR 48.6421-1 - Credits or payments to ultimate purchaser of gasoline used for certain nonhighway purposes.  

Code of Federal Regulations, 2013 CFR

...payments to ultimate purchaser of gasoline used for certain nonhighway purposes...payments to ultimate purchaser of gasoline used for certain nonhighway purposes. (a) In general. (1) If gasoline is used in a qualified...

2013-04-01

87

Estimating the ultimate bound and positively invariant set for a class of Hopfield networks.  

PubMed

In this paper, we investigate the ultimate bound and positively invariant set for a class of Hopfield neural networks (HNNs) based on the Lyapunov stability criterion and Lagrange multiplier method. It is shown that a hyperelliptic estimate of the ultimate bound and positively invariant set for the HNNs can be calculated by solving a linear matrix inequality (LMI). Furthermore, the global stability of the unique equilibrium and the instability region of the HNNs are analyzed, respectively. Finally, the most accurate estimate of the ultimate bound and positively invariant set can be derived by solving the corresponding optimization problems involving the LMI constraints. Some numerical examples are given to illustrate the effectiveness of the proposed results. PMID:21954204

Zhang, Jianxiong; Tang, Wansheng; Zheng, Pengsheng

2011-11-01

88

Temperature dependent elastic constants and ultimate strength of graphene and graphyne  

NASA Astrophysics Data System (ADS)

Based on the first principles calculation combined with quasi-harmonic approximation in this work, we focus on the analysis of temperature dependent lattice geometries, thermal expansion coefficients, elastic constants, and ultimate strength of graphene and graphyne. For the linear thermal expansion coefficient, both graphene and graphyne show a negative region in the low temperature regime. This coefficient increases up to be positive at high temperatures. Graphene has superior mechanical properties with Young's modulus E = 350.01 N/m and ultimate tensile strength of 119.2 GPa at room temperature. Based on our analysis, it is found that graphene's mechanical properties have strong resistance against temperature increase up to 1000 K. Graphyne also shows good mechanical properties with Young's modulus E = 250.9 N/m and ultimate tensile strength of 81.2 GPa at room temperature, but graphyne's mechanical properties have a weaker resistance with respect to the increase of temperature than that of graphene.

Shao, Tianjiao; Wen, Bin; Melnik, Roderick; Yao, Shan; Kawazoe, Yoshiyuki; Tian, Yongjun

2012-11-01

89

Temperature dependent elastic constants and ultimate strength of graphene and graphyne.  

PubMed

Based on the first principles calculation combined with quasi-harmonic approximation in this work, we focus on the analysis of temperature dependent lattice geometries, thermal expansion coefficients, elastic constants, and ultimate strength of graphene and graphyne. For the linear thermal expansion coefficient, both graphene and graphyne show a negative region in the low temperature regime. This coefficient increases up to be positive at high temperatures. Graphene has superior mechanical properties with Young's modulus E = 350.01 N/m and ultimate tensile strength of 119.2 GPa at room temperature. Based on our analysis, it is found that graphene's mechanical properties have strong resistance against temperature increase up to 1000 K. Graphyne also shows good mechanical properties with Young's modulus E = 250.9 N/m and ultimate tensile strength of 81.2 GPa at room temperature, but graphyne's mechanical properties have a weaker resistance with respect to the increase of temperature than that of graphene. PMID:23181329

Shao, Tianjiao; Wen, Bin; Melnik, Roderick; Yao, Shan; Kawazoe, Yoshiyuki; Tian, Yongjun

2012-11-21

90

Intra-Beam Scattering, Impedance, and Instabilities in Ultimate Storage Rings  

SciTech Connect

We have investigated collective effects in an ultimate storage ring, i.e. one with diffraction limited emittances in both planes, using PEP-X as an example. In an ultimate ring intra-beam scattering (IBS) sets the limit of current that can be stored. In PEP-X, a 4.5 GeV ring running round beams at 200 mA in 3300 bunches, IBS doubles the emittances to 11.5 pm at the design current. The Touschek lifetime is 11 hours. Impedance driven collective effects tend not to be important since the beam current is relatively low. We have investigated collective effects in PEP-X, an ultimate storage ring, i.e. one with diffraction limited emittances (at one angstrom wavelength) in both planes. In an ultimate ring intra-beam scattering (IBS) sets the limit of current that can be stored. In PEP-X, IBS doubles the emittances to 11.5 pm at the design current of 200 mA, assuming round beams. The Touschek lifetime is quite large in PEP-X, 11.6 hours, and - near the operating point - increases with decreasing emittance. It is, however, a very sensitive function of momentum acceptance. In an ultimate ring like PEP-X impedance driven collective effects tend not to be important since the beam current is relatively low. Before ultimate PEP-X can be realized, the question of how to run a machine with round beams needs serious study. For example, in this report we assumed that the vertical emittance is coupling dominated. It may turn out that using vertical dispersion is a preferable way to generate round beams. The choice will affect IBS and the Touschek effect.

Bane, Karl; /SLAC

2012-03-28

91

Evaluation of QTL for carcass merit and meat quality traits in a US commercial Duroc population.  

PubMed

Putative quantitative trait loci (QTL) regions on 5 chromosomes (SSC3, 6, 12, 15, and 18) were selected from our previous genome scans of a Duroc×Pietrain F(2) resource population for further evaluation in a US commercial Duroc population (n=331). A total of 81 gene-specific single nucleotide polymorphism (SNP) markers were genotyped and 33 markers were segregating. The MDH1 SNP on SSC3 was associated with 45-min and ultimate pH (pHu), and pH decline. PRKAG3 on SSC15 was associated with pHu. The HSPG2 SNP on SSC6 was associated with marbling score and days to 113kg. Markers for NUP88 and FKBP10 on SSC12 were associated with 45-min pH and L*, respectively. The SSC15 marker SF3B1 was associated with L* and LMA, and the SSC18 marker ARF5 was associated with pHu and color score. These results in a commercial Duroc population showed a general consistency with our previous genome scan. PMID:22578477

Choi, Igseo; Bates, Ronald O; Raney, Nancy E; Steibel, Juan P; Ernst, Catherine W

2012-10-01

92

Ultimate charge sensitivity and efficiency of a quantum point contact with a superposed input state  

NASA Astrophysics Data System (ADS)

We address the ultimate charge detection scheme with a quantum point contact. It is shown that a superposed input state is necessary to exploit the full sensitivity of a quantum point contact detector. The coherence of the input state provides an improvement in charge sensitivity, and this improvement is a result of a fundamental property of the scattering matrix. Further, a quantum-limited (maximally efficient) detection is made possible by controlling the interference between the two output waves. Our scheme provides the ultimate sensitivity and efficiency of charge detection with a generic quantum point contact.

Lee, Kang-Ho; Kang, Kicheon

2013-01-01

93

Space simulation ultimate pressure lowered two decades by removal of diffusion pump oil contaminants during operation  

NASA Technical Reports Server (NTRS)

The complex problem why large space simulation chambers do not realize the true ultimate vacuum was investigated. Some contaminating factors affecting diffusion pump performance have been identified and some advances in vacuum/distillation/fractionation technology have been achieved which resulted in a two decade or more lower ultimate pressure. Data are presented to show the overall or individual contaminating effect of commonly used phthalate ester plasticizers of 390 to 530 molecular weight on diffusion pump performance. Methods for removing contaminants from diffusion pump silicone oil during operation and reclaiming contaminated oil by high vacuum molecular distillation are described.

Buggele, A. E.

1973-01-01

94

Japanese quail meat quality: characteristics, heritabilities, and genetic correlations with some slaughter traits.  

PubMed

The aim of this study was to evaluate the genetic parameters of several breast meat quality traits and their genetic relationships with some slaughter traits [BW, breast yield (BRY), and abdominal fat yield (AFY)]. In total, 1,093 pedigreed quail were slaughtered at 35 d of age to measure BRY, AFY, and breast meat quality traits [ultimate pH (pHU), Commission Internationale d'Eclairage color parameters (L*, lightness; a*, redness; and b*, yellowness), thawing and cooking loss (TL and CL, respectively), and Warner-Bratzler shear value (WB)]. The average pHU, L*, a*, and b* were determined to be 5.94, 43.09, 19.24, and 7.74, respectively. In addition, a very high WB average (7.75 kg) indicated the firmness of breast meat. High heritabilities were estimated for BW, BRY, and AFY (0.51, 0.49, and 0.35). Genetic correlations of BW between BRY and AFY were found to be high (0.32 and 0.58). On the other hand, the moderate negative relationship between BRY and AFY (-0.24) implies that selection for breast yield should not increase abdominal fat. The pHU was found to be the most heritable trait (0.64), whereas the other meat quality traits showed heritabilities in the range of 0.39 to 0.48. Contrary to chickens, the genetic correlation between pHU and L* was low. The pHU exhibited a negative and high correlation with BW and AFY, whereas L* showed a positive but smaller relationship with these traits. Moreover, pHU exhibited high negative correlations (-0.43 and -0.62) with TL and WB, whereas L* showed a moderate relationship (0.24) with CL. This genetic study confirmed that the multi-trait selection could be used to improve meat quality traits. Further, the ultimate pH of breast meat is a relevant selection criterion due to its strong relationships with either water-holding capacity and texture or low abdominal fatness. PMID:23776259

Narinc, Dogan; Aksoy, Tulin; Karaman, Emre; Aygun, Ali; Firat, Mehmet Ziya; Uslu, Mustafa Kemal

2013-07-01

95

Philip Prorok, PhD  

Cancer.gov

Philip Prorok, PhD, mirum est notare quam littera gothica, quam nunc putamus parum claram, anteposuerit litterarum formas humanitatis per seacula quarta decima et quinta decima. Eodem modo typi, qui nunc nobis videntur parum clari, fiant sollemnes in futurum.

96

PhEDEx Data Service  

NASA Astrophysics Data System (ADS)

The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the "SiteDB" service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

Egeland, Ricky; Wildish, Tony; Huang, Chih-Hao

2010-04-01

97

Predicting the Ultimate Load Carrying Capacity of Long-Span Precast Concrete Arch Culverts.  

National Technical Information Service (NTIS)

In a previous full-scale live load test, partially sponsored by the Ohio Department of Transportation, conducted on a 36-ft precast reinforced concrete culvert the ultimate load carrying capacity could not be established due to the limited hydraulic jack'...

M. Zoghi

2000-01-01

98

Determination of heat of combustion of solid wastes from ultimate analysis. Open-file report  

Microsoft Academic Search

The Dulong formula which determines heat of combustion (British thermal units per pound, Btu\\/no.) of coal from an ultimate analysis is not applicable for solid wastes samples. However, with modifications and additions the formula can reasonably estimate heat of combustion of solid waste samples. These modifications and additions to the Dulong formula are discussed.

1971-01-01

99

Predicting the heating value of sewage sludges in Thailand from proximate and ultimate analyses  

Microsoft Academic Search

There have been various methods used for determining a heating value of solid fuel such as coal, biomass and municipal solid waste (MSW) either by experiment using a bomb calorimeter or by modeling based on its compositions. This work proposes another aspect in developing models to predict the heating value of sewage sludge from its proximate and ultimate analyses data.

Puchong Thipkhunthoda

100

Is this the ultimate in recycling. [Legislation in Germany requiring private industry packaging recycling  

Microsoft Academic Search

In Germany, as in the US, packaging waste makes up a third of total municipal solid waste. The principle of polluter pays, or the internalizing of environmental costs by industry is being tested in Germany. Legislation, enacted on June 12, 1991, requires private industry to collect, sort, and ultimately recycle packaging waste including container to hold basic product, secondary packaging,

1993-01-01

101

Simultaneous prediction of coal rank parameters based on ultimate analysis using regression and artificial neural network  

Microsoft Academic Search

Results from ultimate analysis, proximate and petrographic analyses of a wide range of Kentucky coal samples were used to predict coal rank parameters (vitrinite maximum reflectance (Rmax) and gross calorific value (GCV)) using multivariable regression and artificial neural network (ANN) methods. Volatile matter, carbon, total sulfur, hydrogen and oxygen were used to predict both Rmax and GCV by regression and

S. Chehreh Chelgani; Sh. Mesroghli; James C. Hower

2010-01-01

102

Ultimate Lateral Load of a Pile in Soft Clay under Cyclic Loading  

Microsoft Academic Search

In this paper, the ultimate lateral resistance of a long, flexible, unrestrained vertical pile in soft clay is computed under cyclic loading condition using p-y curves. A new method for the construction of p-y curves is proposed. The comparison of calculated results of the proposed method with the field test results reported by Matlock (1970) shows a good agreement. An

D. M. Dewaikar; S. V. Padmavathi; R. S. Salimath

103

Time and Temperature Dependence of the Ultimate Properties of an SBR Rubber at Constant Elongations  

Microsoft Academic Search

The ultimate properties of amorphous rubbers at temperatures above Tg are considered in terms of stress-strain curves to rupture measured at different strain rates and temperatures. The consideration indicates that a specimen held at a fixed elongation should break eventually, provided the elongation exceeds a critical value. This expected behavior was found by studying an SBR rubber. For samples maintained

Thor L. Smith; Paul J. Stedry

1960-01-01

104

Petroleum Market Shares. Report on Sales of Propane to Ultimate Consumers. 1975.  

National Technical Information Service (NTIS)

The report summarizes data, for the period January 1975 through December 1975, provided by refiners and by a sample of independent marketers of propane and propane-butane mixes. Nationally, the total 1975 sales of propane to ultimate consumers as reported...

1976-01-01

105

Student's Ultimate Career Coursework, Employment, & Student Services Handbook. "SUCCESS Handbook" Final Report.  

ERIC Educational Resources Information Center

The Student's Ultimate Career Coursework, Employment and Student Services (SUCCESS) Handbook project was undertaken to identify student support services available through the California Community Colleges (CCC), increase student retention among special needs vocational education students, and identify common barriers to employment. The project…

Foothill-De Anza Community Coll. District, Cupertino, CA. Occupational Training Inst.

106

Seismic Proving Test of Ultimate Piping Strength: Current Status of Preliminary Tests - II  

Microsoft Academic Search

In 1998 FY, the 6 year program of piping tests was initiated with the following objectives: i) to clarify the elasto-plastic response and ultimate strength of nuclear piping, ii) to ascertain the seismic safety margin of the current seismic design code for piping, and iii) to assess new allowable stress rules. In order to resolve extensive technical issues before proceeding

Kenichi Suzuki; Y. Namita; H. Abe; I. Ichihashi; Kohei Suzuki; M. Ishiwata; T. Fujiwaka; H. Yokota

2002-01-01

107

Avoiding Expert Opinions on the Ultimate Legal Question: The Case for Integrity  

Microsoft Academic Search

In this article, we argue against testifying to the ultimate legal issue. There is no basis in science or clinical knowledge for determining the degree of capacity that is required in order to reach the threshold of capacity associated with legal questions such as competency and criminal responsibility. Society qualifies mental health professionals to provide expert testimony on the basis

Chad E. Tillbrook; Denise L. Mumley; Thomas Grisso

2003-01-01

108

Getting "Just Deserts" or Seeing the "Silver Lining": The Relation between Judgments of Immanent and Ultimate Justice  

PubMed Central

People can perceive misfortunes as caused by previous bad deeds (immanent justice reasoning) or resulting in ultimate compensation (ultimate justice reasoning). Across two studies, we investigated the relation between these types of justice reasoning and identified the processes (perceptions of deservingness) that underlie them for both others (Study 1) and the self (Study 2). Study 1 demonstrated that observers engaged in more ultimate (vs. immanent) justice reasoning for a “good” victim and greater immanent (vs. ultimate) justice reasoning for a “bad” victim. In Study 2, participants' construals of their bad breaks varied as a function of their self-worth, with greater ultimate (immanent) justice reasoning for participants with higher (lower) self-esteem. Across both studies, perceived deservingness of bad breaks or perceived deservingness of ultimate compensation mediated immanent and ultimate justice reasoning respectively.

Harvey, Annelie J.; Callan, Mitchell J.

2014-01-01

109

In Vitro Colonization of the Muscle Extracellular Matrix Components by Escherichia coli O157:H7: The Influence of Growth Medium, Temperature and pH on Initial Adhesion and Induction of Biofilm Formation by Collagens I and III  

PubMed Central

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 are responsible for repeated food-poisoning cases often caused by contaminated burgers. EHEC infection is predominantly a pediatric illness, which can lead to life-threatening diseases. Ruminants are the main natural reservoir for EHEC and food contamination almost always originates from faecal contamination. In beef meat products, primary bacterial contamination occurs at the dehiding stage of slaughtering. The extracellular matrix (ECM) is the most exposed part of the skeletal muscles in beef carcasses. Investigating the adhesion to the main muscle fibrous ECM proteins, insoluble fibronectin, collagen I, III and IV, laminin-?2 and elastin, results demonstrated that the preceding growth conditions had a great influence on subsequent bacterial attachment. In the tested experimental conditions, maximal adhesion to fibril-forming collagens I or III occurred at 25°C and pH 7. Once initially adhered, exposure to lower temperatures, as applied to meat during cutting and storage, or acidification, as in the course of post-mortem physiological modifications of muscle, had no effect on detachment, except at pHu. In addition, dense biofilm formation occurred on immobilized collagen I or III and was induced in growth medium supplemented with collagen I in solution. From this first comprehensive investigation of EHEC adhesion to ECM proteins with respect to muscle biology and meat processing, new research directions for the development of innovative practices to minimize the risk of meat contamination are further discussed.

Chagnot, Caroline; Agus, Allison; Renier, Sandra; Peyrin, Frederic; Talon, Regine; Astruc, Thierry; Desvaux, Mickael

2013-01-01

110

Alkaline-induced unfolding and salt-induced folding of pig heart lactate dehydrogenase under high pH conditions  

Microsoft Academic Search

The alkaline-induced unfolding and the salt-induced folding of pig heart lactate dehydrogenase under high pH conditions have been followed by fluorescence emission spectra and circular dichroism spectra. The results for alkaline-induced denaturation of lactate dehydrogenase show that at low ionic strength, increasing the pH value increased the extent of unfolding of the enzyme to the maximum ultimate unfolded conformation at

Ji-Hong Bai; Hao-Jing Wang; Hai-Meng Zhou

1998-01-01

111

Radka Stoyanova, PhD  

Cancer.gov

Dr. Radka Stoyanova, PhD has extensive background in developing approaches to best utilize imaging techniques in cancer research, diagnosis and treatment, as well as in developing approaches for the analysis, mining, and interpretation of "big data" generated by high-throughput approaches such as genomics, proteomics, and metabolomics. She received her Masters Degree in Mathematics from the University of Sofia, Bulgaria. Dr. Stoyanova obtained her doctoral training and PhD degree at the Imperial College London, under the mentorship of Profs.

112

pH Optrode Instrumentation  

NASA Technical Reports Server (NTRS)

pH-sensitive chromophoric reagents immobilized in porous optical fibers. Optoelectronic instrumentation system measures acidity or alkalinity of aqueous nutrient solution. Includes one or more optrodes, which are optical-fiber chemical sensors, in sense, analogous to electrodes but not subject to some of spurious effects distorting readings taken by pH electrodes. Concept of optrodes also described in "Ethylene-Vapor Optrodes" (KSC-11579). pH optrode sensor head, with lead-in and lead-out optical fibers, convenient for monitoring solutions located away from supporting electronic equipment.

Tabacco, Mary Beth; Zhou, Quan

1995-01-01

113

Computational Study of the Ultimate Scaling Limits of CNT Tunneling Devices  

Microsoft Academic Search

The ultimate scaling limits of p-i-n carbon-nanotube field-effect transistors (CNT-FETs) are investigated through numerical simulations based on a quantum-mechanical transport within the nonequilibrium Green's function formalism, based on an energy-dependent effective mass, including inelastic phonon scattering. Starting from the projected specifications of the International Technology Roadmap for Semiconductors for the low-operating-power double-gate MOSFETs, the effect of variations of oxide thickness,

Stefano Poli; Susanna Reggiani; Antonio Gnudi; Elena Gnani; Giorgio Baccarani

2008-01-01

114

The ultimate safe (US) Reactor: A concept for the third millenium  

SciTech Connect

The Ultimate Safe (U.S.) Reactor is based on a novel safety concept. Fission products in the reactor are allowed to accumulate only to a level at which they would constitute a harmless source term. Removal of fission products also removes the decay heat - the driving force for the source term. The reactor has no excess criticality and is controlled by the reactivity temperature coefficient. Safety is inherent and passive. Waste is removed from the site promptly.

Gat, U.

1986-01-01

115

Multiple proximate and ultimate causes of natal dispersal in white-tailed deer  

USGS Publications Warehouse

Proximate and ultimate causes of dispersal in vertebrates vary, and relative importance of these causes is poorly understood. Among populations, inter- and intrasexual social cues for dispersal are thought to reduce inbreeding and local mate competition, respectively, and specific emigration cue may affect dispersal distance, such that inbreeding avoidance dispersal tends to be farther than dispersal to reduce local competition. To investigate potential occurrence of multiple proximate and ultimate causes of dispersal within populations, we radio-marked 363 juvenile male white-tailed deer (Odocoileus virginianus) in 2 study areas in Pennsylvania. Natal dispersal probability and distance were monitored over a 3-year period when large-scale management changes reduced density of adult females and increased density of adult males. Most dispersal (95-97%) occurred during two 12-week periods: spring, when yearling males still closely associate with related females, and prior to fall breeding season, when yearling males closely associate with other breeding-age males. Following changes to sex and age structure that reduced potential for inbreeding and increased potential for mate competition, annual dispersal probability did not change; however, probability of spring dispersal decreased, whereas probability of fall dispersal increased. Spring dispersal distances were greater than fall dispersal distances, suggesting that adaptive inbreeding avoidance dispersal requires greater distance than mate competition dispersal where opposite-sex relatives are philopatric and populations are not patchily distributed. Both inbreeding avoidance and mate competition are important ultimate causes of dispersal of white-tailed deer, but ultimate motivations for dispersal are proximately cued by different social mechanisms and elicit different responses in dispersers.

Long, E. S.; Diefenbach, D. R.; Rosenberry, C. S.; Wallingford, B. D.

2008-01-01

116

Effects of welding residual stress on compressive behavior and ultimate strength of corroded plate  

Microsoft Academic Search

This study examined the effects of welding residual stress on the compressive behavior and the ultimate strength of the corroded\\u000a plate. First, welding residual stress was obtained by the thermal elastic-plastic analysis. Then, the change of welding residual\\u000a stress and the deflection due to the volume loss was investigated by using a newly developed program based on FEM. Finally,\\u000a the

Shingo Tamagawa; You-Chul Kim

2010-01-01

117

Structural Optimization of Air-Guiding Photonic Bandgap Fibers for Realizing Ultimate Low Loss Waveguides  

Microsoft Academic Search

In this paper, we investigate the ultimate low loss property for several realistic core shapes in triangular-type air-guiding photonic bandgap fibers (PBGFs) through a full-vector modal solver based on the finite element method. We show that the surface mode free condition is expressed as a normalized silica-ring thickness T = 0.5 for any core size and the cladding structural parameters,

Tadashi Murao; Kunimasa Saitoh; Masanori Koshiba

2008-01-01

118

An investigation into geometry and microstructural effects upon the ultimate tensile strengths of butt welds  

NASA Technical Reports Server (NTRS)

A mathematical theory was evaluated empirically. This theory predicts weld ultimate tensile strength based on material properties and fusion line angles, mismatch, peaking, and weld widths. Welds were made on 1/4 and 1/2 in. aluminum 2219-T87, their geometries were measured, they were tensile tested, and these results were compared to theoretical predictions. Statistical analysis of results was performed to evaluate correlation of theory to results for many different categories of weld geometries.

Gordon, Stephen S.

1992-01-01

119

The ultimate estimate of the upper norm bound for the summation of operators  

Microsoft Academic Search

Let A and B be bounded linear operators acting on a Hilbert space H. It is shown that the triangular inequality serves as the ultimate estimate of the upper norm bound for the sum of two operators in the sense thatsup{?U*AU+V*BV?:U and V are unitaries}=min{?A+?I?+?B-?I?:??C}.Consequences of the result related to spectral sets, the von Neumann inequality, and normal dilations are

Man-Duen Choi; Chi-Kwong Li

2006-01-01

120

Ultimate capacity of a laser diode in transporting multichannel M-QAM signals  

Microsoft Academic Search

In this paper, we investigate the ultimate M-ary quadrature amplitude modulated (M-QAM) channel capacity of a laser diode which is limited by the laser clipping induced nonlinear distortions. Our study includes a spectral analysis, a complete system simulation, and an experiment which used up to 70 channels of vector arbitrary waveform synthesizer generated quadrature phase shift keyed (QPSK) or 16-QAM

Pi-Yang Chiang

1997-01-01

121

Reliability of Strain-Si FPGA Product Fabricated by Novel Ultimate Spacer Process  

Microsoft Academic Search

Strain-Si field-programmable gate arrays (FPGA) is fabricated by using ultimate spacer process (USP) with a single capping stress liner. An overall 15% speed enhancement without compromising yield was obtained. The product reliability assessment, including HTOL, TCT, ESD (CDM and HBM) and latch-up, was performed simultaneously on USP and control parts. They show comparable product reliability and both pass product specs.

Y. H. Luo; D. Nayak; J. Lee; D. Gitlin; C. T. Tsai

2006-01-01

122

Back Propagation Neural Networks for Predicting Ultimate Strengths of Unidirectional Graphite/Epoxy Tensile Specimens  

NASA Technical Reports Server (NTRS)

The research presented herein demonstrates the feasibility of predicting ultimate strengths in simple composite structures through a neural network analysis of their acoustic emission (AE) amplitude distribution data. A series of eleven ASTM D-3039 unidirectional graphite/epoxy tensile samples were loaded to failure to generate the amplitude distributions for this analysis. A back propagation neural network was trained to correlate the AE amplitude distribution signatures generated during the first 25% of loading with the ultimate strengths of the samples. The network was trained using two sets of inputs: (1) the statistical parameters obtained from a Weibull distribution fit of the amplitude distribution data, and (2) the event frequency (amplitude) distribution itself. The neural networks were able to predict ultimate strengths with a worst case error of -8.99% for the Weibull modeled amplitude distribution data and 3.74% when the amplitude distribution itself was used to train the network. The principal reason for the improved prediction capability of the latter technique lies in the ability of the neural network to extract subtle features from within the amplitude distribution.

Walker, James L.; Hill, Eric v. K.

1993-01-01

123

Making pH Tangible.  

ERIC Educational Resources Information Center

Presents a laboratory exercise in which students test the pH of different substances, study the effect of a buffer on acidic solutions by comparing the behavior of buffered and unbuffered solutions upon the addition of acid, and compare common over-the-counter antacid remedies. (MKR)

McIntosh, Elizabeth; Moss, Robert

1995-01-01

124

Sashwati Roy, PhD  

Cancer.gov

Dr. Sashwati Roy is an Associate Professor of Surgery and Director of the Laser Capture Molecular Core at The Ohio State University, Columbus, Ohio. In 1994 she received her PhD degree in Physiology and Environmental Sciences and later completed her postdoctoral training at the University of California, Berkeley. Dr.

125

Karl Krueger, PhD  

Cancer.gov

Dr. Karl Krueger received a PhD in biochemistry from Vanderbilt University and continued his research training at NIH as a postdoctoral fellow before joining the faculty at Georgetown University School of Medicine. His research throughout this period focused on different aspects of drug receptors and their role in the nervous system.

126

Fluorophilic Ionophores for Potentiometric pH Determinations with Fluorous Membranes of Exceptional Selectivity  

Microsoft Academic Search

Ionophore-doped sensor membranes exhibit greater se- lectivities and wider measuring ranges when they are prepared with noncoordinating matrixes. Since fluorous phases are the least polar and least polarizable liquid phases known, a fluorous phase was used for this work as the membrane matrix for a series of ionophore-based sensors to explore the ultimate limit of selectivity. Fluo- rous pH electrode

Paul G. Boswell; Csongor Szijjarto; Markus Jurisch; John A. Gladysz; Jozsef Rabai; Philippe Bu

2008-01-01

127

PhET Simulation: Density  

NSDL National Science Digital Library

This simulation provides a highly visual, intuitive way for students to explore how density is related to an object's mass and volume. Using a virtual water tank, users drop various objects to see what floats and what sinks. Use the mouse to submerge the object and see how much fluid it displaces. A scale is provided to measure the mass of the objects, with a density table available for view. Students can easily see why the density formula works, especially when they identify the "mystery" objects. Editor's Note: Scroll down on the page for exemplary lesson plans for grades 6-12 developed by the PhET project specifically to accompany the "Density" simulation. This item is part of a larger collection of simulations developed by the Physics Education Technology project (PhET).

2011-02-16

128

Christos Patriotis, PhD  

Cancer.gov

Dr. Christos Patriotis obtained his MSc in Biochemistry from the University of Sofia, Bulgaria in 1985 and his PhD in Molecular Biology from the Bulgarian Academy of Sciences in 1990. Postdoctoral training focused on signal transduction and tumor cell biology. He joined the faculty at Fox Chase Cancer Center in 1998; his research was directed toward understanding mechanisms of breast and ovarian cancer pathogenesis and identification of biomarkers associated with the early stages of the two types of cancer.

129

Engineering Ultimate Self-Protection in Autonomic Agents for Space Exploration Missions  

NASA Technical Reports Server (NTRS)

NASA's Exploration Initiative (EI) will push space exploration missions to the limit. Future missions will be required to be self-managing as well as self-directed, in order to meet the challenges of human and robotic space exploration. We discuss security and self protection in autonomic agent based-systems, and propose the ultimate self-protection mechanism for such systems-self-destruction. Like other metaphors in Autonomic Computing, this is inspired by biological systems, and is the analog of biological apoptosis. Finally, we discus the role it might play in future NASA space exploration missions.

Sterritt, Roy; Hinchey, Mike

2005-01-01

130

Measurement of ultimate tensile strength and Young modulus in LYSO scintillating crystals  

Microsoft Academic Search

Scintillating crystals are employed in high energy physics, in medical imaging, diagnostic and security. Two mechanical properties of lutetium–yttrium oxyorthosilicate cerium-doped Lu2(1?x)Y2xSiO5:Ce with x=0.1 (LYSO) crystals have been measured: the ultimate tensile stress (?UTS) and the Young elastic modulus (E). Measurements are made by means of a 4-points loading device and the experimental results account for an elastic–brittle stress–strain relation,

Lorenzo Scalise; Daniele Rinaldi; Fabrizio Davì; Nicola Paone

2011-01-01

131

Lava ultimate resin nano ceramic for CAD/ CAM: customization case study.  

PubMed

Lava Ultimate Resin Nano Ceramic (RNC) blocks are innovative new CAD/CAM materials that make it possible to achieve superior esthetic results in easy steps. The blocks are made of nano ceramic particles embedded in a highly cured resin matrix. Therefore, composite materials can be used to characterize and adjust resin nano ceramic restorations after milling. The milled RNC restorations can be individualized intra-orally or extra-orally, either before or after insertion. Unlike conventional ceramic restorations, customization and glaze firing is neither necessary nor possible with RNC restorations. This opens up the opportunity for intraoral individualization and adaptation of the restorations. PMID:22891419

Koller, M; Arnetzl, G V; Holly, L; Arnetzl, G

2012-01-01

132

Effect of Ph on Human Complement Activity.  

National Technical Information Service (NTIS)

The influence of pH on the haemolytic activity of human complement (HuC') was investigated over the pH range 5.55-8.20. Maximum haemolytic activity of HuC' was observed at pH 6.77 and not at the pH level (7.2) usually used. Adjustment of pH to either the ...

B. J. Fogel W. A. Hook E. H. Fife

1966-01-01

133

26 CFR 48.6420-1 - Credits or payments to ultimate purchaser of gasoline used on a farm.  

Code of Federal Regulations, 2013 CFR

...Credits or payments to ultimate purchaser of gasoline used on a farm. 48.6420-1 Section...Credits or payments to ultimate purchaser of gasoline used on a farm. (a) In general. If gasoline is used on a farm for farming...

2013-04-01

134

26 CFR 48.6427-9 - Diesel fuel and kerosene; claims by registered ultimate vendors (farming and State use).  

Code of Federal Regulations, 2013 CFR

...claims by registered ultimate vendors (farming and State use). 48.6427-9 Section...claims by registered ultimate vendors (farming and State use). (a) Overview...and kerosene sold for use on a farm for farming purposes and by a State. Claims...

2013-04-01

135

Plasticity and constraints on social evolution in African mole-rats: ultimate and proximate factors  

PubMed Central

Here, we review comparative studies of African mole-rats (family Bathyergidae) to explain how constraints acting at the ultimate (environmental) and proximate (organismal) levels have led to convergent gains and losses of sociality within this extensive adaptive radiation of subterranean rodents endemic to sub-Saharan Africa. At the ultimate level, living in environments that range from mesic through to arid has led to both variation and flexibility in social organization among species, culminating in the pinnacle of social evolution in the eusocial naked and Damaraland mole-rats (Heterocephalus glaber and Fukomys damarensis). The common mole-rat (Cryptomys hottentotus) provides a model example of how plasticity in social traits exists within a single species inhabiting areas with different ecological constraint. At the proximate level, reproductive strategies and cooperative breeding may be constrained by the correlated evolution of a suite of traits including physiological suppression of reproduction, the development of physiological and morphological castes, and the mode of ovulatory control and seasonality in breeding. Furthermore, recent neurobiological advances indicate that differential patterns of neurotransmitter expression within the forebrain may underpin (and limit) either a solitary or group living/cooperative lifestyle not only in mole-rats, but also more widely among disparate mammalian taxa.

Faulkes, Chris G.; Bennett, Nigel C.

2013-01-01

136

ULtiMATE System for Rapid Assembly of Customized TAL Effectors  

PubMed Central

Engineered TAL-effector nucleases (TALENs) and TALE-based constructs have become powerful tools for eukaryotic genome editing. Although many methods have been reported, it remains a challenge for the assembly of designer-based TALE repeats in a fast, precise and cost-effective manner. We present an ULtiMATE (USER-based Ligation Mediated Assembly of TAL Effector) system for speedy and accurate assembly of customized TALE constructs. This method takes advantage of uracil-specific excision reagent (USER) to create multiple distinct sticky ends between any neighboring DNA fragments for specific ligation. With pre-assembled templates, multiple TALE DNA-binding domains could be efficiently assembled in order within hours with minimal manual operation. This system has been demonstrated to produce both functional TALENs for effective gene knockout and TALE-mediated gene-specific transcription activation (TALE-TA). The feature of both ease-of-operation and high efficiency of ULtiMATE system makes it not only an ideal method for biologic labs, but also an approach well suited for large-scale assembly of TALENs and any other TALE-based constructions.

Wen, Dingqiao; Sheng, Ying; Zhu, Shiyou; Yu, Yuezhou; Gao, Xiang; Wei, Wensheng

2013-01-01

137

The theoretical ultimate magnetoelectric coefficients of magnetoelectric composites by optimization design  

NASA Astrophysics Data System (ADS)

This paper investigates what is the largest magnetoelectric (ME) coefficient of ME composites, and how to realize it. From the standpoint of energy conservation, a theoretical analysis is carried out on an imaginary lever structure consisting of a magnetostrictive phase, a piezoelectric phase, and a rigid lever. This structure is a generalization of various composite layouts for optimization on ME effect. The predicted theoretical ultimate ME coefficient plays a similar role as the efficiency of ideal heat engine in thermodynamics, and is used to evaluate the existing typical ME layouts, such as the parallel sandwiched layout and the serial layout. These two typical layouts exhibit ME coefficient much lower than the theoretical largest values, because in the general analysis the stress amplification ratio and the volume ratio can be optimized independently and freely, but in typical layouts they are dependent or fixed. To overcome this shortcoming and achieve the theoretical largest ME coefficient, a new design is presented. In addition, it is found that the most commonly used electric field ME coefficient can be designed to be infinitely large. We doubt the validity of this coefficient as a reasonable ME effect index and consider three more ME coefficients, namely the electric charge ME coefficient, the voltage ME coefficient, and the static electric energy ME coefficient. We note that the theoretical ultimate value of the static electric energy ME coefficient is finite and might be a more proper measure of ME effect.

Wang, H.-L.; Liu, B.

2014-03-01

138

Ultimate Heat Sink Thermal Performance and Water Utilization: Measurements on Cooling and Spray Ponds  

SciTech Connect

A data acquisition research program, entitled "Ultimate Heat Sink Performance Field Experiments," has been brought to completion. The primary objective is to obtain the requisite data to characterize thermal performance and water utilization for cooling ponds and spray ponds at elevated temperature. Such data are useful for modeling purposes, but the work reported here does not contain modeling efforts within its scope. The water bodies which have been studied are indicative of nuclear reactor ultimate heat sinks, components of emergency core cooling systems. The data reflect thermal performance and water utilization for meteorological and solar influences which are representative of worst-case combinations of conditions. Constructed water retention ponds, provided with absolute seals against seepage, have been chosen as facilities for the measurement programs; the first pond was located at Raft River, Idaho, and the second at East Mesa, California. The data illustrate and describe, for both cooling ponds and spray ponds, thermal performance and water utilization as the ponds cool from an initially elevated temperature. To obtain the initial elevated temperature, it has been convenient to conduct the measurements at geothermal sites having large supplies and delivery rates of hot geothermal fluid. The data are described and discussed in the text, and presented in the form of data volumes as appendices.

Athey, G. F.; Hadlock, R. K.; Abbey, 0. B.

1982-02-01

139

PERFORMANCE EVALUATION OF A 32-ELEMENT HEAD ARRAY WITH RESPECT TO THE ULTIMATE INTRINSIC SNR  

PubMed Central

The quality of an RF detector coil design is commonly judged on how it compares with other coil configurations. The aim of this article is to develop a tool for evaluating the absolute performance of RF coil arrays. An algorithm to calculate the ultimate intrinsic signal-to-noise ratio (SNR) was implemented for a spherical geometry. The same imaging tasks modeled in the calculations were reproduced experimentally using a 32-element head array. Coil performance maps were then generated based on the ratio of experimentally measured SNR to the ultimate intrinsic SNR, for different acceleration factors associated with different degrees of parallel imaging. The relative performance in all cases was highest near the center of the samples (where the absolute SNR was lowest). The highest performance was found in the unaccelerated case and a maximum of 85% was observed with a phantom whose electrical properties are consistent with values in the human brain. The performance remained almost constant for 2-fold acceleration, but deteriorated at higher acceleration factors, suggesting that larger arrays are needed for effective highly-accelerated parallel imaging. The method proposed here can serve as a tool for the evaluation of coil designs, as well as a tool to guide the development of original designs which may begin to approach the optimal performance.

Lattanzi, Riccardo; Grant, Aaron K.; Polimeni, Jonathan R.; Ohliger, Michael A.; Wiggins, Graham C.; Wald, Lawrence L.; Sodickson, Daniel K.

2010-01-01

140

Plasticity and constraints on social evolution in African mole-rats: ultimate and proximate factors.  

PubMed

Here, we review comparative studies of African mole-rats (family Bathyergidae) to explain how constraints acting at the ultimate (environmental) and proximate (organismal) levels have led to convergent gains and losses of sociality within this extensive adaptive radiation of subterranean rodents endemic to sub-Saharan Africa. At the ultimate level, living in environments that range from mesic through to arid has led to both variation and flexibility in social organization among species, culminating in the pinnacle of social evolution in the eusocial naked and Damaraland mole-rats (Heterocephalus glaber and Fukomys damarensis). The common mole-rat (Cryptomys hottentotus) provides a model example of how plasticity in social traits exists within a single species inhabiting areas with different ecological constraint. At the proximate level, reproductive strategies and cooperative breeding may be constrained by the correlated evolution of a suite of traits including physiological suppression of reproduction, the development of physiological and morphological castes, and the mode of ovulatory control and seasonality in breeding. Furthermore, recent neurobiological advances indicate that differential patterns of neurotransmitter expression within the forebrain may underpin (and limit) either a solitary or group living/cooperative lifestyle not only in mole-rats, but also more widely among disparate mammalian taxa. PMID:23569295

Faulkes, Chris G; Bennett, Nigel C

2013-05-19

141

1-Sulfooxymethylpyrene is an electrophilic mutagen and ultimate carcinogen of 1-methyl- and 1-hydroxymethylpyrene.  

PubMed

1-Hydroxymethylpyrene and 1-sulfooxymethylpyrene were tested for complete carcinogenic activity by repeated s.c. injection in groups of 12 female Sprague-Dawley rats, respectively. A dose of 0.2 mumol of either 1-sulfooxymethylpyrene or 1-hydroxymethylpyrene was administered every other weekday for 20 doses (i.e., total dose 4 mumol) to each of 12 rats, beginning at 30 days of age. Once a week the rats were weighed then palpated for the appearance of tumors. Tumor-bearing rats were sacrificed 20-50 days after the appearance of first palpable tumor. By 52 weeks, 1-sulfooxymethylpyrene had induced sarcomas at the site of injection in 58% of the rats with an average induction time of 33 weeks. By contrast, 20, 0.2 mumol doses of 1-hydroxymethylpyrene failed to induce tumors at the site of injection in a group of 12 rats. Similarly, neither of the two control groups produced tumors. The present experiment, together with previous data, strongly supports the hypothesis that 1-sulfooxymethylpyrene is either itself an ultimate carcinogen or a direct precursor of an ultimate carcinogen, the highly reactive benzylic carbonium ion, which reacts with DNA to form aralkyl-DNA adducts in a chain of events leading to malignant growth. PMID:8912643

Horn, J; Flesher, J W; Lehner, A F

1996-11-01

142

Modified multi-walled carbon nanotubes potentially suitable for intracellular pH measurements  

NASA Astrophysics Data System (ADS)

Carboxylic acid functionalized multi-walled carbon nanotubes (COOH-MWCNTs) have been studied as macromolecular carriers for pH indicators to be used inside cells. The activation of carboxylic groups with thionyl chloride (SOCl2) followed by the reaction with a family of fluorescein ethylen glycol derivatives led to dyes covalently anchored to the MWCNT surface. Such a functionalization was found to preserve wholly the fluorescence properties of the dye ultimately providing higher water solubility to the modified macromolecular systems. Moreover, the use of a polyether spacer between the dye and the MWCNT surface preserved from undesired florescence quenching effects. The pH dependence of the modified nanotubes was investigated interrogating a solution of MWCNTs, the pH of which was adjusted in the range 4-9 pH units by adding drops of hydrochloric acid and sodium hydroxide. Light from LED was suitably filtered at 480 nm with a high pass-band filter and coupled to an optical fiber which illuminates the solution containing the fluorescein-functionalised MWCNTs. An optical fiber, at 90° with respect to the LED illumination, is connected with a Hamamtsu spectrum analyzer for the recording of the fluorescence spectra. The modified MWCNTs exhibited linear pH dependence in the range between 6 and 8 pH units with a sensitivity less than 0.1 pH units.

Ghini, Giacomo; Puleo, Gian Luigi; Trono, Cosimo; Giannetti, Ambra; Luconi, Lapo; Bianchini, Claudio; Giambastiani, Giuliano; Baldini, Francesco

2010-02-01

143

The pH of antiseptic cleansers  

PubMed Central

Background Daily bathing with antiseptic cleansers are proposed by some physicians as an adjunctive management of atopic dermatitis (AD). As atopic skin is sensitive, selection of cleansing products becomes a topic of concern. Objective Our purpose is to evaluate the pH of various antiseptic body cleansers to give an overview for recommendation to patients with AD. Methods Commonly bar and liquid cleansers consisted of antiseptic agents were measured for pH using pH meter and pH-indicator strips. For comparison, mild cleansers and general body cleansers were also measured. Results All cleansing bars had pH 9.8-11.3 except syndet bar that had neutral pH. For liquid cleansers, three cleansing agents had pH close to pH of normal skin, one of antiseptic cleansers, one of mild cleansers and another one of general cleansers. The rest of antiseptic cleansers had pH 8.9-9.6 while mild cleansers had pH 6.9-7.5. Syndet liquid had pH 7 and general liquid cleansers had pH 9.6. Conclusion The pH of cleanser depends on composition of that cleanser. Adding antiseptic agents are not the only factor determining variation of pH. Moreover, benefit of antiseptic properties should be considered especially in cases of infected skin lesions in the selection of proper cleansers for patients with AD.

Kulthanan, Kanokvalai; Varothai, Supenya; Nuchkull, Piyavadee

2014-01-01

144

Welcomed within Graceland, Elvis impersonators gather for finals of the first "Ultimate Elvis" contest  

NSDL National Science Digital Library

The King serves motorists at Roseburg Albertson's, will entertain for employeeshttp://www.newsreview.info/article/20070814/NEWS/70814022Ultimate Elvis Contest [pdf]http://www.elvis.com/ultimatecontest/How Did Elvis Get Turned Into a Racist?http://www.elvis.com.au/presley/peter_guralnick__elvis_racist.shtmlJoe Moscheo's The Gospel of Elvis Presleyhttp://www.cmt.com/news/articles/1566978/20070813/presley_elvis.jhtmlElvis: 30 weird and wonderful factshttp://www.belfasttelegraph.co.uk/entertainment/music-gigs/news/article2859595.eceAmazing Grace [Real Player]http://lcweb2.loc.gov/diglib/ihas/loc.natlib.ihas.200149090/default.htmlIf imitation is in fact the sincerest form of flattery, then the late Elvis Presley must certainly be flattered someplace in the great beyond. Even before he passed away thirty years ago, there were Elvis impersonators (some prefer the term "tribute artist") who traveled the globe performing as the King of Rock and Roll in a variety of guises. The permutations are seemingly endless, and they include those who adopt Elvis's signature late 1960s massive sideburns and still others whose sartorial style is not complete with a jumpsuit overloaded with sequins and other trappings. The folks who have managed Elvis's estate and Graceland have generally been dismissive of these tribute artists. However, this indifference has recently changed into a rather warm welcome as the company that operates Graceland will pay host to the first annual finals of the "Ultimate Elvis" contest this Friday. The contest has been going on since March, and one grand prize winner will be selected in what promises to be quite a competition. While some Elvis devotees may still look askance at such events, Paul Jankowski, the marketing chief of Elvis Presley Enterprises, Inc. was emphatic as he spoke about this event: "This is not an impersonator contest. This is all about paying tribute to Elvis." The first link will take visitors to a piece from this Tuesday's Washington Post which talks about the "Ultimate Elvis" contest at Graceland. Several thousand miles away in Roseburg, Oregon, The News-Review recently reported on Jerry Norby, a newly minted Elvis, and his first day on the job. Visitors can read about Norby and his work pumping gas and singing "My Way" at the second link. The third link leads to the homepage of the Ultimate Elvis Contest. Here, visitors can learn about the finalists and read a letter from Elvis to a tribute artist. The fourth link leads to a recent editorial by Elvis biographer Peter Guralnick which first appeared in the New York Times. In the piece, Guralnick addresses the "absurd claims" that contend Elvis was a racist. For another perspective on Elvis's life, visitors will want to check out the fifth link, which contains an excerpt from Joe Moscheo's recent book which recalls his time performing with Elvis and his well-documented love of gospel music. The sixth link leads to a listing of thirty little-known facts about Elvis, including the observation that his Grammy Awards all came from his numerous gospel recordings. The final link leads to one such recording, which happens to be his 1971 recording of "Amazing Grace".

Grinnell, Max

2007-08-17

145

Biomimetics and the Development of Humanlike Robots as the Ultimate Challenge  

NASA Technical Reports Server (NTRS)

Evolution led to effective solutions to nature's challenges and they were improved over millions of years. Humans have always made efforts to use nature as a model for innovation and problems solving. These efforts became more intensive in recent years where systematic studies of nature are being made towards better understanding and applying more sophisticated capabilities. Making humanlike robots, including the appearance, functions and intelligence, poses the ultimate challenges to biomimetics. For many years, making such robots was considered science fiction, but as a result of significant advances in biologically inspired technologies, such robots are increasingly becoming an engineering reality. There are already humanlike robots that walk, talk, interpret speech, make eye-contact and facial expressions, as well as perform many other humanlike functions. In this paper, the state-of-the-art of humanlike robots, potential applications and issues of concern will be reviewed.

Bar-Cohen, Yoseph

2011-01-01

146

Ultimate capacity evaluation of reinforced concrete slabs using yield line analysis  

SciTech Connect

Yield line theory offers a simplified nonlinear analytical method that can determine the ultimate bending capacity of flat reinforced concrete planes subject to distributed and concentrated loads. Alternately, yield line theory, combined with hinge rotation limits can determine the energy absorption capacity of plates subject to impulsive and impact loads. This method is especially useful in evaluating existing structures that cannot be qualified using conservative simplifying analytical assumptions. Typical components analyzed by yield line theory are basements, floor and roof slabs subject to vertical loads along with walls subject to out of plant wall loads. One limitation of yield line theory is that it is difficult to evaluate some mechanisms; this is aggravated by the complex geometry and reinforcing layouts commonly found in practice. A yield line evaluation methodology is proposed to solve computationally tedious yield line mechanisms. This methodology is implemented in a small PC based computer program that allows the engineer to quickly evaluate multiple yield line mechanisms.

Mertz, G.E.

1995-12-31

147

[Pilot scale research on impacts of leachate recirculation on its ultimate treatment].  

PubMed

Two pilot scale simulated columns, with and without leachate recirculation, were erected to study impacts of leachate recirculation of traditional anaerobic bioreactor landfill on leachate ultimate treatment methods. The results indicate that recirculation can remove organic pollutants visibly, but it isn't effective to inbiodegradable components, nitrogen (N) and phosphorus (P) pollutants. After recircualted for 44 weeks, test column has a BODs removal ratio of 98.5%. BOD5/COD value of outflow is only 0.07. BOD5/TN and BOD5/TP are 0.13 and 11 respectively, which are much lower than the adequate value for anaerobic microorganisms. It's difficult to treat this kind of leachate by traditional biological methods. When a bioreactor landfill is being designed, leachate characteristics after recirculated should be well considered and adequate leachate treatment, landfill and recirculation schemes should be chosen to take full advantage of waste stack decontamination effects. PMID:16921969

Deng, Zhou; Jiang, Jian-guo; Huang, Zhong-lin; Feng, Xiang-ming; Zhou, Sheng-yong; Yang, Guo-dong

2006-06-01

148

Regions of attraction and ultimate boundedness for linear quadratic regulators with nonlinearities  

NASA Technical Reports Server (NTRS)

The closed-loop stability of multivariable linear time-invariant systems controlled by optimal linear quadratic (LQ) regulators is investigated for the case when the feedback loops have nonlinearities N(sigma) that violate the standard stability condition, sigma N(sigma) or = 0.5 sigma(2). The violations of the condition are assumed to occur either (1) for values of sigma away from the origin (sigma = 0) or (2) for values of sigma in a neighborhood of the origin. It is proved that there exists a region of attraction for case (1) and a region of ultimate boundedness for case (2), and estimates are obtained for these regions. The results provide methods for selecting the performance function parameters to design LQ regulators with better tolerance to nonlinearities. The results are demonstrated by application to the problem of attitude and vibration control of a large, flexible space antenna in the presence of actuator nonlinearities.

Joshi, S. M.

1984-01-01

149

Coordinated breathing in bottlenose dolphins (Tursiops truncatus) as cooperation: integrating proximate and ultimate explanations.  

PubMed

In this study, coordinated breathing was studied in 13 common bottlenose dolphins because of its links with spontaneous coordinated behaviors (e.g., swimming, foraging, and playing). A strong link was shown between dyadic coordination levels and age/sex categories when both association patterns and spatial formation are considered. This is consistent with a significant influence of social relationships on cooperating and contrasts with an economic perspective based on immediate material outcomes alone. This cooperation bias is explained by linking proximate processes that evoke performance with ultimate evolutionary processes driven by long-term adaptive outcomes. Proximate processes can include 2 kinds of immediate outcomes: material reinforcements and affective states associated with acts of cooperating that can provide positive reinforcement regardless of immediate material benefits (e.g., when there is a time lag between cooperative acts and material outcomes). Affective states can then be adaptive by strengthening social relationships that lead to eventual gains in fitness. PMID:18489227

Perelberg, Amir; Schuster, Richard

2008-05-01

150

Pulmonary interstitial glycogenosis in a patient ultimately diagnosed with Noonan syndrome.  

PubMed

We describe an infant prenatally diagnosed with hydrops fetalis ultimately found to have Noonan syndrome (NS). Prior to genetic confirmation of diagnosis, lung biopsy was performed which revealed widespread pulmonary interstitial glycogenosis (PIG), abnormal alveolarization, and mild inflammation. Although genetic alterations have been identified in NS, the mutations are heterogeneous and the diagnosis remains one of clinical suspicion. The combination of PIG and NS has not yet been documented in the literature. While the underlying pathophysiologic mechanism of PIG is unclear, we suggest that the mitogen-activated protein kinase signal transduction pathway members (PTPN11, KRAS, SOS1, RAF1, SHOC2, NRAS) involved in cellular growth factor signaling, which are affected in NS, can provide clues. In addition, this case demonstrates that empiric corticosteroids can be considered in complicated cases since biopsy did reveal an inflammatory component, not typically noted in PIG. PMID:24039098

Ross, Mindy K; Ellis, Linda S; Bird, Lynne M; Hagood, James S

2014-05-01

151

Assessing Fatigue and Ultimate Load Uncertainty in Floating Offshore Wind Turbines Due to Varying Simulation Length  

SciTech Connect

With the push towards siting wind turbines farther offshore due to higher wind quality and less visibility, floating offshore wind turbines, which can be located in deep water, are becoming an economically attractive option. The International Electrotechnical Commission's (IEC) 61400-3 design standard covers fixed-bottom offshore wind turbines, but there are a number of new research questions that need to be answered to modify these standards so that they are applicable to floating wind turbines. One issue is the appropriate simulation length needed for floating turbines. This paper will discuss the results from a study assessing the impact of simulation length on the ultimate and fatigue loads of the structure, and will address uncertainties associated with changing the simulation length for the analyzed floating platform. Recommendations of required simulation length based on load uncertainty will be made and compared to current simulation length requirements.

Stewart, G.; Lackner, M.; Haid, L.; Matha, D.; Jonkman, J.; Robertson, A.

2013-07-01

152

Stapledon's Interplanetary Man: A Commonwealth of Worlds and the Ultimate Purpose of Space Colonisation  

NASA Astrophysics Data System (ADS)

In his 1948 lecture to the British Interplanetary Society Stapledon considered the ultimate purpose of colonising other worlds. Having examined the possible motivations arising from improved scientific knowledge and access to extraterrestrial raw materials, he concludes that the ultimate benefits of space colonisation will be the increased opportunities for developing human (and post-human) diversity, intellectual and aesthetic potential and, especially, `spirituality'. By the latter concept he meant a striving for ``sensitive and intelligent awareness of things in the universe (including persons), and of the universe as a whole.'' A key insight articulated by Stapledon in this lecture was that this should be the aspiration of all human development anyway, with or without space colonisation, but that the latter would greatly increase the scope for such developments. Another key aspect of his vision was the development of a diverse, but connected, `Commonwealth of Worlds' extending throughout the Solar System, and eventually beyond, within which human potential would be maximised. In this paper I analyse Stapledon's vision of space colonisation, and will conclude that his overall conclusions remain sound. However, I will also argue that he was overly utopian in believing that human social and political unity are prerequisites for space exploration (while agreeing that they are desirable objectives in their own right), and that he unnecessarily downplayed the more prosaic scientific and economic motivations which are likely to be key drivers for space exploration (if not colonisation) in the shorter term. Finally, I draw attention to some recent developments in international space policy which, although probably not influenced by Stapledon's work, are nevertheless congruent with his overarching philosophy as outlined in `Interplanetary Man?'.

Crawford, Ian A.

153

PhDAHP1 is required for floral volatile benzenoid/phenylpropanoid biosynthesis in Petunia × hybrida cv 'Mitchell Diploid'.  

PubMed

Floral volatile benzenoid/phenylpropanoid (FVBP) biosynthesis consists of numerous enzymatic and regulatory processes. The initial enzymatic step bridging primary metabolism to secondary metabolism is the condensation of phosphoenolpyruvate (PEP) and erythrose-4-phosphate (E4P) carried out via 3-DEOXY-D-ARABINO-HEPTULOSONATE-7-PHOSPHATE (DAHP) synthase. Here, identified, cloned, localized, and functionally characterized were two DAHP synthases from the model plant species Petunia × hybrida cv 'Mitchell Diploid' (MD). Full-length transcript sequences for PhDAHP1 and PhDAHP2 were identified and cloned using cDNA SMART libraries constructed from pooled MD corolla and leaf total RNA. Predicted amino acid sequence of PhDAHP1 and PhDAHP2 proteins were 76% and 80% identical to AtDAHP1 and AtDAHP2 from Arabidopsis, respectively. PhDAHP1 transcript accumulated to relatively highest levels in petal limb and tube tissues, while PhDAHP2 accumulated to highest levels in leaf and stem tissues. Through floral development, PhDAHP1 transcript accumulated to highest levels during open flower stages, and PhDAHP2 transcript remained constitutive throughout. Radiolabeled PhDAHP1 and PhDAHP2 proteins localized to plastids, however, PhDAHP2 localization appeared less efficient. PhDAHP1 RNAi knockdown petunia lines were reduced in total FVBP emission compared to MD, while PhDAHP2 RNAi lines emitted 'wildtype' FVBP levels. These results demonstrate that PhDAHP1 is the principal DAHP synthase protein responsible for the coupling of metabolites from primary metabolism to secondary metabolism, and the ultimate biosynthesis of FVBPs in the MD flower. PMID:24815009

Langer, Kelly M; Jones, Correy R; Jaworski, Elizabeth A; Rushing, Gabrielle V; Kim, Joo Young; Clark, David G; Colquhoun, Thomas A

2014-07-01

154

Defining and Teaching pH  

Microsoft Academic Search

The 1909 definition of pH given in most general chemistry textbooks conflicts with the modern, operationally-defined pH scale that underlies laboratory measurement and relates to activities. At an elementary level, pH and the algebra of equilibria can be simply and correctly taught, without logarithms, in terms of the latter scale.

Richard F. Burton

2007-01-01

155

Petroleum Market Shares: A Report on Sales of Distillate and Residual Fuel Oil to Ultimate Consumers, 1975.  

National Technical Information Service (NTIS)

This report presents the results of the Federal Energy Administration (FEA) survey of firms that sold distillate and residual fuel oil to ultimate consumers during the period January 1, 1975, through December 31, 1975. Nationally, refiner-marketers sold a...

1976-01-01

156

Direct Ultimate Disposal of Spent Fuel Elements. Preparatory Tests for Selection of a Suitable Packing Method. Final Report.  

National Technical Information Service (NTIS)

The pneumatic packing method and the slinger stowing method have been tested under boundary conditions valid for an ultimate disposal site, and have been evaluated quality. Two test series have been made, accompanied by extensive sampling work and analyse...

K. H. Wildt

1987-01-01

157

PhET Simulation: Sound  

NSDL National Science Digital Library

This interactive simulation allows users to analyze the properties of sound waves. Frequency and amplitude can be controlled, and users can enable audio tones to explore how pitch is related to frequency. Other options allow users to experiment with constructive and destructive interference by moving positions of speakers and listeners. Tools are also provided to measure wavelengths of various frequencies. Experimenting with interference from a wall and exploring sound in environments without air pressure are also possible. This simulation is part of a large and growing collection developed by the Physics Educational Technology Project using research-based principles. See the Related Materials below for a link to clicker questions and tutorials designed specifically for this simulation by the PhET team.

2008-10-29

158

Soil pH and Fertilizers  

NSDL National Science Digital Library

This Web site by the Mississippi State University Extension Service discusses why fertilizers are added to soils. The Web site begins by introducing the concept of the pH of the soil and how nutrients are affected by this pH level. Students can then learn about the pH logarithmic scale and about the factors that affect soil pH. At the end of the site, users will find a clear and concise table concerning different fertilizer materials characteristics including their speed of reaction and effect on pH in soils.

159

Soils - Part 4: Soil pH  

NSDL National Science Digital Library

Soil pH is defined and its implications for crop production are described in this lesson. How are soil pH and buffer pH determined? How are these assessments used in lime recommendations? The factors that influence pH variations in soils, the chemistry involved in changing the pH of a soil, and the benefits associated with liming acid soils will be discussed.[This lesson, as well as the other nine lessons in the Soils series, is taken from the "Soils Home Study Course," published in 1999 by the University of Nebraska Cooperative Extension.

160

How to Relate Complex DNA Repair Genotypes to Pathway Function and, Ultimately, Health Risk  

SciTech Connect

Exposure to ionizing radiation increases the incidence of cancer. However, predicting which individuals are at most risk from radiation exposure is a distant goal. Predictive ability is needed to guide policies that regulate radiation exposure and ensure that medical treatments have maximum benefit and minimum risk. Differences between people in susceptibility to radiation are largely based on their genotype, the genes inherited from their parents. Among the important genes are those that produce proteins that repair DNA damaged by radiation. Base Excision Repair (BER) proteins repair single strand breaks and oxidized bases in DNA. Double Strand Break Repair proteins repair broken chromosomes. Using technologies and information from the Human Genome Project, we have previously determined that the DNA sequence of DNA repair genes varies within the human population. An average of 3-4 different variants were found that affect the protein for each of 37 genes studied. The average frequency of these variants is 5%. Given the many genes in each DNA repair pathway and their many variants, technical ability to determine an individual's repair genotype greatly exceeds ability to interpret the information. A long-term goal is to relate DNA repair genotypes to health risk from radiation. This study focused on the BER pathway. The BER genes are known, variants of the genes have been identified at LLNL, and LLNL had recently developed an assay for BER function using white blood cells. The goal of this initial effort was to begin developing data that could be used to test the hypothesis that many different genotypes have similar DNA repair capacity phenotypes (function). Relationships between genotype and phenotype could then be used to group genotypes with similar function and ultimately test the association of groups of genotypes with health risk from radiation. Genotypes with reduced repair function are expected to increase risk of radiation-induced health effects. The goal of this pilot project was to obtain preliminary data on genetic variation in DNA repair function in human cells that might encourage our efforts to establish a research program to relate DNA repair function to complex DNA repair genotype and ultimately to cancer risk of radiation exposure.

Jones, IM

2002-01-09

161

Lattice Design for PEP-X Ultimate Storage Ring Light Source  

SciTech Connect

SLAC expertise in designing and operating high current storage rings and the availability of the 2.2-km PEP-II tunnel present an opportunity for building a next generation light source - PEP-X - that would replace the SPEAR3 storage ring in the future. The PEP-X 'baseline' design, with 164 pm-rad emittance at 4.5 GeV beam energy and a current of 1.5 A, was completed in 2010. As a next step, a so-called 'ultimate' PEP-X lattice, reducing the emittance to 11 pm-rad at zero current, has been designed. This emittance approaches the diffraction limited photon emittance for multi-keV photons, providing near maximum photon brightness and high coherence. It is achieved by using 7-bend achromat cells in the ring arcs and a 90-m damping wiggler in one of the 6 long straight sections. Details of the lattice design, dynamic aperture, and calculations of the intra-beam scattering effect and Touschek lifetime at a nominal 0.2 A current are presented. Accelerator-based light sources are in high demand for many experimental applications. The availability of the 2.2-km PEP-II tunnel at SLAC presents an opportunity for building a next generation light source - PEP-X - that would replace the existing SPEAR3 light source in the future. The PEP-X study started in 2008, and the 'baseline' design, yielding 164 pm-rad emittance at 4.5 GeV beam energy and a current of 1.5 A, was completed in 2010. This relatively conservative design can be built using existing technology. However, for a long term future, it is natural to investigate a more aggressive, so-called 'ultimate' ring design. The goal is to reduce the electron emittance in both x and y planes to near the diffraction limited photon emittance of 8 pm-rad at hard X-ray photon wavelength of 0.1 nm. This would provide a near maximum photon brightness and significant increase in photon coherence. This study was motivated by the advances in low emittance design at MAX-IV. The latter was used as a starting point for the PEP-X arc lattice, however new features were included into the design for better tuning capabilities and compensation of non-linear optics effects. Further emittance reduction is achieved with a 90-m damping wiggler. Finally, intra-beam scattering (IBS) and Touschek lifetime effects were estimated and cross-checked using various codes.

Bane, K.L.F.; Cai, Y.; Nosochkov, Y.; Wang, M.-H.; /SLAC; Hettel, R.O.; /SLAC

2011-12-13

162

Effect of Load Rate on Ultimate Tensile Strength of Ceramic Matrix Composites at Elevated Temperatures  

NASA Technical Reports Server (NTRS)

The strengths of three continuous fiber-reinforced ceramic composites, including SiC/CAS-II, SiC/MAS-5 and SiC/SiC, were determined as a function of test rate in air at 1100 to 1200 C. All three composite materials exhibited a strong dependency of strength on test rate, similar to the behavior observed in many advanced monolithic ceramics at elevated temperatures. The application of the preloading technique as well as the prediction of life from one loading configuration (constant stress-rate) to another (constant stress loading) suggested that the overall macroscopic failure mechanism of the composites would be the one governed by a power-law type of damage evolution/accumulation, analogous to slow crack growth commonly observed in advanced monolithic ceramics. It was further found that constant stress-rate testing could be used as an alternative to life prediction test methodology even for composite materials, at least for short range of lifetimes and when ultimate strength is used as the failure criterion.

Choi, Sung R.; Gyekenyesi, John P.

2001-01-01

163

Bottlenose dolphins (Tursiops truncatus) prefer to cooperate when petted: Integrating proximate and ultimate explanations II.  

PubMed

Cooperation poses theoretical problems because the behaviors of individuals can benefit others. Evolutionary and game-theory explanations that focus on maximizing one's own material outcomes are usually supported by experimental models with isolated and anonymous subjects. Cooperation in the natural world, however, is often a social act whereby familiar individuals coordinate behaviors for shared outcomes. Social cooperation is also associated with a cooperation bias expressed as a preference for cooperation even when noncooperation is immediately more beneficial. The authors report on evidence for such a bias in a captive group of bottlenose dolphins that voluntarily preferred to receive petting from human guides by using a pairwise coordinated approach, even though this was more difficult, and total petting amount was thereby reduced. To explain why this bias occurs, the authors propose an integrated behavioral-evolutionary approach whereby performance is determined by two kinds of immediate outcomes: material gains and intrinsic affective states associated with cooperating. The latter can provide reinforcement when immediate material gains are reduced, delayed, or absent. Over a lifetime, this proximate mechanism can lead to cooperative relationships whose long-term ultimate consequences can be adaptive. PMID:19236144

Perelberg, Amir; Schuster, Richard

2009-02-01

164

Reproductive skew in female common marmosets: what can proximate mechanisms tell us about ultimate causes?  

PubMed

Common marmosets are cooperatively breeding monkeys that exhibit high reproductive skew: most subordinate females fail to reproduce, while others attempt to breed but produce very few surviving infants. An extensive dataset on the mechanisms limiting reproduction in laboratory-housed and free living subordinate females provides unique insights into the causes of reproductive skew. Non-breeding adult females undergo suppression of ovulation and inhibition of sexual behaviour; however, they receive little or no aggression or mating interference by dominants and do not exhibit behavioural or physiological signs of stress. Breeding subordinate females receive comparable amounts of aggression to non-breeding females but are able to conceive, gestate and lactate normally. In groups containing two breeding females,however, both dominant and subordinate breeders kill one another's infants. These findings suggest that preconception reproductive suppression is not imposed on subordinate females by dominants, at a proximate level, but is instead self-imposed by most subordinates, consistent with restraint models of reproductive skew. In contrast to restraint models, however, this self-suppression probably evolved not in response to the threat of eviction by dominant females but in response to the threat of infanticide. Thus,reproductive skew in this species appears to be generated predominantly by subordinate self-restraint, in a proximate sense, but ultimately by dominant control over subordinates' reproductive attempts. PMID:18945663

Saltzman, Wendy; Digby, Leslie J; Abbott, David H

2009-02-01

165

A novel pathway to the ultimate mutagens of aromatic amino and nitro compounds.  

PubMed Central

Photolysis of arylazides in aqueous media was recently found to generate presumed nitrenium ions, species which are generally considered as the ultimate mutagens/carcinogens derived from arylamines and nitroarenes. The primary photolysis products of arylazides, the arylnitrenes, can possibly react as electrophiles themselves, or they can be protonated and thus form the electrophilic nitrenium ions. Numerous arylazides and aryldiazides can be photoactivated to short-lived mutagens detectable in Salmonella typhimurium TA98. Structure-activity comparisons between arylazides and the matching arylamines and nitroarenes show correlations; e.g., phenyl azide and methyl-substituted phenyl azides are not mutagenic or only weakly mutagenic like aniline, nitrobenzene, and their methyl homologues, whereas 4-azidodiphenyl, 2-azidofluorene, 1-azidopyrene, azido-IQ, and azido-isoIQ are increasingly mutagenic in that order, like the matching amino and nitro compounds. It is hypothesized on the basis of these data that the nitrene/nitrenium ion is the reactive intermediate common to the three mutagenic pathways and that the reaction of the nitrene/nitrenium ion with DNA is rate limiting for the overall mutagenic process in Salmonella. The photochemical generation from arylazides of the reactive species, the nitrene/nitrenium ions, opens new perspectives for the understanding of the genotoxic activity of arylamines and nitroarenes in general and, specifically, of the food mutagens/carcinogens of the IQ type.

Wild, D

1990-01-01

166

NDM-1, the ultimate promiscuous enzyme: substrate recognition and catalytic mechanism  

PubMed Central

The specter of a return to an era in which infectious disease looms as a significant threat to human health is not just hyperbole; there are serious concerns about the widespread overuse and misuse of antibiotics contributing to increased antibiotic resistance in pathogens. The recent discovery of a new enzyme, first identified in Klebsiella pneumoniae from a patient from New Delhi and denoted as NDM-1, represents an example of extreme promiscuity: It hydrolyzes and inactivates nearly all known ?-lactam-based antibiotics with startling efficiency. NDM-1 can utilize different metal cofactors and seems to exploit an alternative mechanism based on the reaction conditions. Here we report the results of a combined experimental and theoretical study that examines the substrate, metal binding, and catalytic mechanism of the enzyme. We utilize structures obtained through X-ray crystallography, biochemical assays, and numerical simulation to construct a model of the enzyme catalytic pathway. The NDM-1 enzyme interacts with the substrate solely through zinc, or other metals, bound in the active site, explaining the observed lack of specificity against a broad range of ?-lactam antibiotic agents. The zinc ions also serve to activate a water molecule that hydrolyzes the ?-lactam ring through a proton shuttle.—Kim, Y., Cunningham, M. A.; Mire, J., Tesar, C., Sacchettini, J., Joachimiak, A. NDM-1, the ultimate promiscuous enzyme: substrate recognition and catalytic mechanism.

Kim, Youngchang; Cunningham, Mark A.; Mire, Joseph; Tesar, Christine; Sacchettini, James; Joachimiak, Andrzej

2013-01-01

167

Online PH measurement technique in seawater desalination  

NASA Astrophysics Data System (ADS)

The measurement technology of pH is essential in seawater desalination. Glass electrode is the main pH sensor in seawater desalination. Because the internal impedance of glass electrode is high and the signal of pH sensor is easy to be disturbed, a signal processing circuit with high input impedance was designed. Because of high salinity of seawater and the characteristic of glass electrode, ultrasonic cleaning technology was used to online clean pH sensor. Temperature compensation was also designed to reduce the measurement error caused by variety of environment temperature. Additionally, the potential drift of pH sensor was analyzed and an automatic calibration method was proposed. In order to online monitor the variety of pH in seawater desalination, three operating modes were designed. The three modes are online monitoring mode, ultrasonic cleaning mode and auto-calibration mode. The current pH in seawater desalination was measured and displayed in online monitoring mode. The cleaning process of pH sensor was done in ultrasonic cleaning mode. The calibration of pH sensor was finished in auto-calibration mode. The result of experiments showed that the measurement technology of pH could meet the technical requirements for desalination. The glass electrode could be promptly and online cleaned and its service life was lengthened greatly.

Wang, Haibo; Wu, Kaihua; Hu, Shaopeng

2009-11-01

168

Functional photoacoustic microscopy of pH  

NASA Astrophysics Data System (ADS)

pH is a tightly regulated indicator of metabolic activity. In mammalian systems, imbalance of pH regulation may result from or result in serious illness. Even though the regulation system of pH is very robust, tissue pH can be altered in many diseases such as cancer, osteoporosis and diabetes mellitus. Traditional high-resolution optical imaging techniques, such as confocal microscopy, routinely image pH in cells and tissues using pH sensitive fluorescent dyes, which change their fluorescence properties with the surrounding pH. Since strong optical scattering in biological tissue blurs images at greater depths, high-resolution pH imaging is limited to penetration depths of 1mm. Here, we report photoacoustic microscopy (PAM) of commercially available pH-sensitive fluorescent dye in tissue phantoms. Using both opticalresolution photoacoustic microscopy (OR-PAM), and acoustic resolution photoacoustic microscopy (AR-PAM), we explored the possibility of recovering the pH values in tissue phantoms. In this paper, we demonstrate that PAM was capable of recovering pH values up to a depth of 2 mm, greater than possible with other forms of optical microscopy.

Chatni, M. Rameez; Yao, Junjie; Danielli, Amos; Favazza, Christopher P.; Maslov, Konstantin I.; Wang, Lihong V.

2012-02-01

169

Dynamic regulation of gastric surface pH by luminal pH  

PubMed Central

In vivo confocal imaging of the mucosal surface of rat stomach was used to measure pH noninvasively under the mucus gel layer while simultaneously imaging mucus gel thickness and tissue architecture. When tissue was superfused at pH 3, the 25 ?m adjacent to the epithelial surface was relatively alkaline (pH 4.1 ± 0.1), and surface alkalinity was enhanced by topical dimethyl prostaglandin E2 (pH 4.8 ± 0.2). Luminal pH was changed from pH 3 to pH 5 to mimic the fasted-to-fed transition in intragastric pH in rats. Under pH 5 superfusion, surface pH was relatively acidic (pH 4.2 ± 0.2). This surface acidity was enhanced by pentagastrin (pH 3.5 ± 0.2) and eliminated by omeprazole, implicating parietal cell H,K-ATPase as the dominant regulator of surface pH under pH 5 superfusion. With either pH 5 or pH 3 superfusion (a) gastric pit lumens had the most divergent pH from luminal superfusates; (b) qualitatively similar results were observed with and without superfusion flow; (c) local mucus gel thickness was a poor predictor of surface pH values; and (d) no channels carrying primary gastric gland fluid through the mucus were observed. The model of gastric defense that includes an alkaline mucus gel and viscous fingering of secreted acid through the mucus may be appropriate at the intragastric pH of the fasted, but not fed, animal. J. Clin. Invest. 103:605–612 (1999)

Chu, Shaoyou; Tanaka, Shin; Kaunitz, Jonathan D.; Montrose, Marshall H.

1999-01-01

170

Ultimate contact hole resolution using immersion lithography with line/space imaging  

NASA Astrophysics Data System (ADS)

Contact Hole (CH) resolution is limited by the low aerial image contrast using dark field masks. Moreover the 2- Dimensional character of CH is a limiting factor in the use of extreme Resolution Enhancement Techniques for reaching the smallest pitch. These limitations can be overcome if one deconvolves the 2D CH into two exposures of 1D structures (i.e. lines). These 1D structures can indeed be printed at the ultimate resolution limit of the scanner using dipole exposures. Recently, several materials have become available to pattern CH from such a double exposure of line patterns. It is shown in this paper how this concept of deconvolution can be used in different techniques: Two 1D aerial images can be recomposed in order to obtain 2D images which will subsequently be reversed into CH. We can distinguish, on the one hand, a reversal based on the positive development of line crossings into resist pillar patterns, on which are deposited or coated a gap-fill material layer. The pillars are then removed, leaving a masking material layer with holes. On the other hand, negative tone development can be used to reverse directly the recomposed 2D aerial image: while the classical positive development creates pillars, the negative tone development inverses immediately this image to create contact holes in the resist layer. In this paper, we demonstrate the potential of the double exposure method. We characterise three reversal techniques using a NA=1.35 immersion scanner for patterning 40nm or lower CH at pitch 80nm. We also show etch performance of these processes and address the complexity of each solution.

Truffert, V.; Bekaert, J.; Lazzarino, F.; Maenhoudt, M.; Miller, A.; Moelants, M.; Wu, T.

2009-03-01

171

BNL NONLINEAR PRE TEST SEISMIC ANALYSIS FOR THE NUPEC ULTIMATE STRENGTH PIPING TEST PROGRAM.  

SciTech Connect

The Nuclear Power Engineering Corporation (NUPEC) of Japan has been conducting a multi-year research program to investigate the behavior of nuclear power plant piping systems under large seismic loads. The objectives of the program are: to develop a better understanding of the elasto-plastic response and ultimate strength of nuclear piping; to ascertain the seismic safety margin of current piping design codes; and to assess new piping code allowable stress rules. Under this program, NUPEC has performed a large-scale seismic proving test of a representative nuclear power plant piping system. In support of the proving test, a series of materials tests, static and dynamic piping component tests, and seismic tests of simplified piping systems have also been performed. As part of collaborative efforts between the United States and Japan on seismic issues, the US Nuclear Regulatory Commission (USNRC) and its contractor, the Brookhaven National Laboratory (BNL), are participating in this research program by performing pre-test and post-test analyses, and by evaluating the significance of the program results with regard to safety margins. This paper describes BNL's pre-test analysis to predict the elasto-plastic response for one of NUPEC's simplified piping system seismic tests. The capability to simulate the anticipated ratcheting response of the system was of particular interest. Analyses were performed using classical bilinear and multilinear kinematic hardening models as well as a nonlinear kinematic hardening model. Comparisons of analysis results for each plasticity model against test results for a static cycling elbow component test and for a simplified piping system seismic test are presented in the paper.

DEGRASSI,G.; HOFMAYER,C.; MURPHY,C.; SUZUKI,K.; NAMITA,Y.

2003-08-17

172

Functional photoacoustic microscopy of pH  

Microsoft Academic Search

pH is a tightly regulated indicator of metabolic activity. In mammalian systems, an imbalance of pH regulation may result from or result in serious illness. In this paper, we report photoacoustic microscopy (PAM) of a commercially available pH-sensitive fluorescent dye (SNARF-5F carboxylic acid) in tissue phantoms. We demonstrated that PAM is capable of pH imaging in absolute values at tissue

Muhammad Rameez Chatni; Junjie Yao; Amos Danielli; Christopher P. Favazza; Konstantin I. Maslov; Lihong V. Wang

2011-01-01

173

The PH20 Protein in Human Spermatozoa  

Microsoft Academic Search

PH-20 is a sperm plasma-membrane protein that has been shown to have hyaluronidase activity in several mammalian species including nonhuman primates. In this investigation, the PH-20 protein was characterized in noncapacitated human sperm and in capacitated human sperm. Two forms of PH-20 were ob- served in immunoblots of sodium dodecylsulfate polyacrylamide-gel electrophoresis (SDS PAGE) using a polyclonal antibody to recom-

KHALIDA SABEUR; GARY N. CHERR; ASHLEY I. YUDIN; PAUL PRIMAKOFF; MING-WEN LI; JAMES W. OVERSTREET

174

The pH of estuarine waters  

Microsoft Academic Search

The emf measurements for the TRIS buffer in seawater have been used to define buffer solutions that can be used to determine the pH on a free or total proton scale for estuarine waters. The pH is related to the stoichiometric dissociation constant (K*) of TRISH I-, the concentration of buffer (mTRrs) and salinity (5) by pH = pK* +

FRANK J. MILLERO

1986-01-01

175

26 CFR 48.6421-2 - Credits or payments to ultimate purchasers of gasoline used in intercity, local, or school buses.  

Code of Federal Regulations, 2013 CFR

...payments to ultimate purchasers of gasoline used in intercity, local, or school...payments to ultimate purchasers of gasoline used in intercity, local, or school buses. (a) In general. If gasoline is used in an intercity...

2013-04-01

176

Ultimate Tensile Strength as a Function of Test Rate for Various Ceramic Matrix Composites at Elevated Temperatures  

NASA Technical Reports Server (NTRS)

Ultimate tensile strength of five different continuous fiber-reinforced ceramic composites, including SiC/BSAS (2D 2 types), SiC/MAS-5 (2D), SiC/SiC (2D enhanced), and C/SiC(2D) was determined as a function of test rate at I 100 to 1200 'C in air. All five composite materials exhibited a significant dependency of ultimate strength on test rate such that the ultimate strength decreased with decreasing test rate, similar to the behavior observed in many advanced monolithic ceramics at elevated temperatures. The application of the preloading technique as well as the prediction of life from one loading configuration (constant stress rate) to another (constant stress loading) for SiC/BSAS suggested that the overall macroscopic failure mechanism of the composites would be the one governed by a power-law type of damage evolution/accumulation, analogous to slow crack growth commonly observed in advanced monolithic ceramics.

Choi, Sung R.; Bansal, Narottam P.; Gyekenyesi, John P.

2002-01-01

177

Characterisation of Phaseolus symbionts isolated from Mediterranean soils and analysis of genetic factors related to pH tolerance  

Microsoft Academic Search

The ultimate objective of PhIMED, in which two European (Germany, Italy) and two Mediterranean (Morocco, Egypt) countries collaborate, is to improve the cultivation of French bean (Phaseolusvulgaris) under arid and semi-arid conditions by analysing and enhancing stress tolerance of the nitrogen fixing rhizobial microsymbionts. Rhizobial strains nodulating P.vulgaris (RP strains) isolated from areas in Morocco frequently subjected to drought were

U. B Priefer; J Aurag; B Boesten; I Bouhmouch; R Defez; A Filali-Maltouf; M Miklis; H Moawad; B Mouhsine; J Prell; A Schlüter; B Senatore

2001-01-01

178

Anthropogenic carbon and ocean pH  

NASA Astrophysics Data System (ADS)

The burning of fossil fuels and forests increases atmospheric CO2 content, which drives a CO2 flux into the ocean, and thereby makes the ocean more acidic. The effects of increased CO2 and decreased ocean pH may individually and in combination have significant consequences for marine biota We present ocean pH change results from ocean geochemistry and ocean general circulation models for both atmospheric CO2 change scenarios and ocean carbon sequestration scenarios. Unsurprisingly, the pH decrease in the ocean reflects the spatial and temporal distribution of anthropogenic carbon. However, the pH response of the ocean depends sensitively on the rate at which carbon is added to the ocean. When CO2 changes occur over hundreds of thousands of years and longer, ocean carbonate-ion concentration is buffered by interaction with carbonate sediments, buffering ocean pH. However, when CO2 changes occur over decades and centuries, ocean alkalinity remains roughly constant, tending to make ocean pH relatively sensitive to changes in ocean carbon content. A doubling of atmospheric CO2 over a few centuries would decrease ocean pH by ~0.3 units. This is roughly the magnitude of pH variation over the past ~50 million years inferred from boron isotopes. There is no evidence of such rapid pH variation of this magnitude in the geologic record (with possible exceptions for rare catastrophic events). If CO2 is emitted as per the IPCC IS92a ``Business as Usual'' scenario, or even as per most of the proposed CO2 stabilization scenarios, ocean pH may decrease by an amount and at a rate not experienced by the Earth for the past few tens of millions of years. The biological consequences of such pH changes are uncertain at present.

Caldeira, K.; Wickett, M. E.; Duffy, P. B.; Barry, J. P.

2001-12-01

179

Predictors of binge drinking in adolescents: ultimate and distal factors - a representative study  

PubMed Central

Background As epidemiological surveys have shown, binge drinking is a constant and wide-spread problem behavior in adolescents. It is not rare to find that more than half of all adolescents engage in this behavior when assessing only the last 4 weeks of time independent of the urbanity of the region they live in. There have been several reviews on predictors of substance consumption in adolescents in general, but there has been less high quality research on predictors of binge drinking, and most studies have not been theoretically based. The current study aimed to analyze the ultimate and distal factors predicting substance consumption according to Petraitis' theory of triadic influence. We assessed the predictive value of these factors with respect to binge drinking in German adolescents, including the identification of influence direction. Methods In the years 2007/2008, a representative written survey of N = 44,610 students in the 9th grade of different school types in Germany was carried out (net sample). The return rate of questionnaires was 88% regarding all students whose teachers or school directors had agreed to participate in the study. In this survey, prevalence of binge drinking was investigated as well as potential predictors from the social/interpersonal, the attitudinal/environmental, and the intrapersonal fields (3 factors of Petraitis). In a multivariate logistic regression analysis, these variables were included after testing for multicollinearity in order to assess their ability to predict binge drinking. Results Prevalence of binge drinking in the last 30 days was 52.3% for the surveyed adolescents with a higher prevalence for boys (56.9%) than for girls (47.5%). The two most influential factors found to protect against binge drinking with p < .001 were low economic status and importance of religion. The four most relevant risk factors for binge drinking (p < .001) were life-time prevalence of school absenteeism/truancy, academic failure, suicidal thoughts, and violence at school in the form of aggressive behavior of teachers. The model of Petraitis was partly confirmed for Binge Drinking in German adolescents and the direction of influence factors was clarified. Conclusions Whereas some of the risk and protective factors for binge drinking are not surprising since they are known for substance abuse in general, there are two points that could be targeted in interventions that do not focus on adolescents alone: (a) training teachers in positive, reassuring behavior and constructive criticism and (b) a focus on high risk adolescents either because they have a lack of coping strategies when in a negative mood or because of their low academic achievement in combination with absenteeism from school.

2012-01-01

180

The Extreme Globular Cluster System of Abell 1689: The Ultimate Test of Universal Formation Efficiency  

NASA Astrophysics Data System (ADS)

The stellar masses of the most luminous galaxies poorly represent the masses of the halos in which they reside. However, recent studies of the very rich globular cluster {GC} populations in the centers of galaxy clusters point toward an apparently linear scaling of the number of GCs with the total core mass of the galaxy cluster. Thus, unlike for the stars in cD galaxies, GC formation in these systems appears to have proceeded with a roughly universal mass conversion efficiency. GCs are also distinct in that their spatial distributions are more extended than the starlight, and recent simulations suggest that they follow the mass density profile of the merged dark matter halos that formed stars at high redshift. To provide a definitive test of the universal efficiency hypothesis requires measuring the number of GCs in the most massive galaxy clusters, where the number should be a factor of 5 or more greater than seen in M87. Likewise, the relationship between GCs and mass density can only be tested in systems where the total mass and mass density are well-determined. Fortunately, the imaging power of HST brings the GC population of Abell 1689, the most extreme high-mass lensing cluster, into range. Estimates of the size of the A1689 GC population from available data suggest an unprecedented 100,000 GCs, but this number is based on the tip of the iceberg and is extremely uncertain. We propose to obtain the first accurate measurement of the number of GCs and their density profile in this extraordinary system - the most massive and most distant GC system ever studied - and thus make the ultimate test of the universal GC formation hypothesis. Our deep I-band image will also provide a stringent "null-detection" test of several known z>7 galaxy candidates and improve the mass model of the system by increasing the number of usable lensed background galaxies. Finally, we will take deep multi-band parallel observations with WFC3/IR to help in quantifying the abundance of rare faint red objects.;

Blakeslee, John

2008-07-01

181

Response to the "Responsive PhD"  

ERIC Educational Resources Information Center

In June 2005, 50 graduate school deans gathered at Princeton to address the fact that the number of new PhDs conferred each year far exceeds the number of tenure-track academic jobs on offer. Under the auspices of the Woodrow Wilson National Fellowship Foundation's Responsive PhD Project, these deans spoke passionately about how American…

Huyssen, David

2007-01-01

182

pH. Agricultural Lesson Plans.  

ERIC Educational Resources Information Center

This lesson plan is intended for use in conducting classes on the effect of pH on plant growth. Presented first are an attention step/problem statement and a series of questions and answers designed to convey general information about soil pH and its effect on plants. The following topics are among those discussed: acidity and alkalinity; the…

Southern Illinois Univ., Carbondale. Dept. of Agricultural Education and Mechanization.

183

CALCULATING THE PH OF CALCIUM CARBONATE SATURATION  

EPA Science Inventory

Two new expressions for the pH of saturation (pH subs) were derived. One is a simplified equation developed from an aqueous carbonate equilibrium system in which correction for ionic strength was considered. The other is a more accurate quadratic formula that involves computerize...

184

Frequently Asked Questions for Parents of Children with PH  

MedlinePLUS

... International PH News and Projects Let Me Breathe Music Video Families Patients Newly Diagnosed Request an Envelope ... International PH News and Projects Let Me Breathe Music Video Help spread PH awareness and share PH ...

185

Smart pH cuvette for optical monitoring of pH of biological samples  

NASA Astrophysics Data System (ADS)

A Smart pH Cuvette is developed by coating the inner surface with pH sensitive thin film. The coating is a hydroscopic sol-gel material doped with colorimetric pH indicator dye sensitive to the pH of analyte solutions in biological range. Ocean optics miniaturized spectrometers are used for signal detection and analysis, along with multimode optical fibers. This new pH sensing arrangement yields an inexpensive solution for monitoring the pH of samples for biological applications. The Smart pH Cuvettes provide a resolution of 0.01 pH units, an accuracy of 1% of the reading, and 90% response in less than 10 seconds.

Guenther, Derek A.; Shahriari, Mahmoud R.

2010-02-01

186

Regression models of ultimate methane yields of fruits and vegetable solid wastes, sorghum and napiergrass on chemical composition  

Microsoft Academic Search

Several fractions of fruits and vegetable solid wastes (FVSW), sorghum and napiergrass were analyzed for total solids (TS), volatile solids (VS), total organic carbon, total kjeldahl nitrogen, total soluble carbohydrate, extractable protein, acid–detergent fiber (ADF), lignin, cellulose and ash contents. Their ultimate methane yields (Bo) were determined using the biochemical methane potential (BMP) assay. A series of simple and multiple

V. Nallathambi Gunaseelan

2007-01-01

187

Ultimate beam capacity limit of fibre grating based true-time-delay beam-formers for phased arrays  

Microsoft Academic Search

A new grating based beam-former is presented which can synthesise a large number of beams with the minimum number of interconnects. A partitioned WDM grating topology is also described which removes the frequency and beat noise limits, and results are presented for the ultimate capacity of grating true-time-delay beam-formers

Robert A. Minasian; Kamal E. Alameh

1998-01-01

188

ARSENIC (III) METHYLATED SPECIES REACT WITH DNA DIRECTLY AND COULD BE PROXIMATED/ULTIMATE GENOTOXIC FORMS OF ARSENIC  

EPA Science Inventory

ARSENIC(III) METHYLATED SPECIES REACT WITH DNA DIRECTL Y AND COULD BE PROXIMATE/ULTIMATE GENOTOXIC FORMS OF ARSENIC Arsenite and arsenate (iAs, inorganic arsenic) have been thought to act as genotoxicants without reacting directly with DNA; neither iAs nor As(V) m...

189

Ultimate recovery analysis by formation and play for deep Anadarko Basin and estimation of undiscovered gas potential  

SciTech Connect

Deep gas resources have assumed a growing role in the United States gas picture since the mid-1960s. The deep Anadarko basin has been one of the areas of heavy activity, and is thought to contain a significant portion of the remaining unproven deep gas resource in the lower-48 states. A detailed analysis of gas production and proven reserves in the deep basin has established the characteristics and historical importance of each of the major plays and productive formations. The analysis should prove to be a valuable tool in estimating the undiscovered gas potential of the deep basin. Through 1985, there were 908 completions in the deep Anadarko basin. These completions accounted for 6.10 tcf of proven ultimate recovery, an average of 6.72 bcf per completion. In general, there is one completion per well and one well per section. Thus, ultimate recovery per completion represents ultimate recovery per section. The Hunton Group has the highest mean ultimate recovery at 15.3 bcf, followed by the Arbuckle Group at 10.1 bcf. In an attempt to evaluate existing resource appraisals of the deep basin, the areal distribution of production by formation was determined for the mature, shallow part of the basin. Over 20,000 completions were included in this analysis, demonstrating a significant database application. By using this distribution as a guide, along with certain other constraints, a range of 15-47 tcf of undiscovered potential was estimated.

Hugman, R.H.

1988-01-01

190

The ‘ultimate objective’ of the framework convention on climate change requires a new approach in climate change research  

Microsoft Academic Search

In the Framework Convention on Climate Change an ‘ultimate objective’ is formulated that calls for stabilization of the concentrations of greenhouse gases in the atmosphere at a level that would allow ecosystems to adapt naturally, safeguard food supply and enable sustainable development to proceed in a sustainable manner. This paper addresses the possible contribution of science to translate this rather

Robert J. Swart; Pier Vellinga

1994-01-01

191

The Utilization of Spin Polarized Photoelectron Spectroscopy as a Probe of Electron Correlation with an Ultimate Goal of Pu  

SciTech Connect

We are developing the technique of spin-polarized photoelectron spectroscopy as a probe of electron correlation with the ultimate goal of resolving the Pu electronic structure controversy. Over the last several years, we have demonstrated the utility of spin polarized photoelectron spectroscopy for determining the fine details of the electronic structure in complex systems such as those shown in the paper.

Tobin, James; Yu, Sung; Chung, Brandon; Morton, Simon; Komesu, Takashi; Waddill, George

2008-02-11

192

The Utilization of Spin Polarized Photoelectron Spectroscopy as a Probe of Electron Correlation with an Ultimate Goal of Pu  

SciTech Connect

We are developing the technique of spin-polarized photoelectron spectroscopy as a probe of electron correlation with the ultimate goal of resolving the Pu electronic structure controversy. Over the last several years, we have demonstrated the utility of spin polarized photoelectron spectroscopy for determining the fine details of the electronic structure in complex systems such as those shown in this report.

Tobin, J G; Yu, S W; Chung, B W; Morton, S A; Komesu, T; Waddill, G D

2008-02-07

193

Management of Ultimate Risk of Nuclear Power Plants by Source Terms - Lessons Learned from the Chernobyl Accident  

Microsoft Academic Search

The term 'ultimate risk' is used here to describe the probabilities and radiological consequences that should be incorporated in siting, containment design and accident management of nuclear power plants for hypothetical accidents. It is closely related with the source terms specified in siting criteria which assures an adequate separation of radioactive inventories of the plants from the public, in the

Genn Saji

2006-01-01

194

Embedding of human vertebral bodies leads to higher ultimate load and altered damage localisation under axial compression.  

PubMed

Computer tomography (CT)-based finite element (FE) models of vertebral bodies assess fracture load in vitro better than dual energy X-ray absorptiometry, but boundary conditions affect stress distribution under the endplates that may influence ultimate load and damage localisation under post-yield strains. Therefore, HRpQCT-based homogenised FE models of 12 vertebral bodies were subjected to axial compression with two distinct boundary conditions: embedding in polymethylmethalcrylate (PMMA) and bonding to a healthy intervertebral disc (IVD) with distinct hyperelastic properties for nucleus and annulus. Bone volume fraction and fabric assessed from HRpQCT data were used to determine the elastic, plastic and damage behaviour of bone. Ultimate forces obtained with PMMA were 22% higher than with IVD but correlated highly (R(2) = 0.99). At ultimate force, distinct fractions of damage were computed in the endplates (PMMA: 6%, IVD: 70%), cortex and trabecular sub-regions, which confirms previous observations that in contrast to PMMA embedding, failure initiated underneath the nuclei in healthy IVDs. In conclusion, axial loading of vertebral bodies via PMMA embedding versus healthy IVD overestimates ultimate load and leads to distinct damage localisation and failure pattern. PMID:23237518

Maquer, Ghislain; Schwiedrzik, Jakob; Zysset, Philippe K

2014-09-01

195

The quest for ultimate patterning tools and techniques - focused ion beams: status, future applications and new ideas  

Microsoft Academic Search

The aim of this presentation is to present our results and new ideas aiming to explore the nano-structuring potential of ultimately focussed pencils of ions and charged clusters. We will show that Focused Ion Beam technology (FIB) is capable of overcoming some basic limitations of current nano-fabrication techniques and to allow innovative patterning schemes, in particular for nanoscience. We will

Jacques Gierak; Ralf Jede; Peter Hawkes; Günter Zschornack; Ali Madouri; Joël Thomas; Klaus Hasselbach

196

Ultimate Attainment in Late Second Language Acquisition: Phonetic and Grammatical Challenges in Advanced Dutch-English Bilingualism  

ERIC Educational Resources Information Center

The present article provides an exploration of ultimate attainment in second language (L2) and its limitations. It is argued that the question of maturational constraints can best be investigated when the reference population is bilingual and exposed on a regular basis to varieties of their first language (L1) that show cross-linguistic influence.…

Schmid, Monika S.; Gilbers, Steven; Nota, Amber

2014-01-01

197

EFFECT OF PH ON HUMAN MYCOPLASMA STRAINS.  

PubMed

Shepard, Maurice C. (U.S. Naval Medical Field Research Laboratory, Camp Lejeune, N.C.), and Carl D. Lunceford. Effect of pH on human Mycoplasma strains. J. Bacteriol. 89:265-270. 1965.-The optimal reaction of culture media for the cultivation of T-strain Mycoplasma of human origin was investigated. By use of a recently modified tryptic digest medium, the optimal reaction in either agar or fluid medium was found to be pH 6.0. In contrast, human classic (large-colony) Mycoplasma could be cultivated in agar or fluid medium over a rather broad pH range, and the influence of the reaction of the medium appeared to be primarily species-dependent. M. salivarium, for example, grew best in agar from pH 5.5 through 6.5. M. pneumoniae (Easton's agent) yielded largest colony numbers in agar and highest titers in broth at pH 8.0. In the case of T-strain Mycoplasma, both maximal colony numbers in agar and highest titers in fluid media were achieved at a reaction of pH 6.0. In addition, largest colony size of T-strain Mycoplasma was also achieved in agar at pH 6.0, and averaged 50 to 100% larger than that obtained by cultivation at pH 8.0 with the same medium. Although T-strains will develop in agar media over a pH range of from 5.0 through 10.0, the extremely small colony size and poor staining properties resulting from growth in an alkaline medium make their recognition in agar cultures difficult. Aerobic cultivation of T-strains was first achieved in agar adjusted to pH 5.5 to 6.0. In fluid medium, multiplication of T-strains occurred only within the limits of pH 5.0 through 8.0, with highest titers being reached at pH 6.0. Greater attention to the reaction of complete Mycoplasma media is stressed. PMID:14255688

SHEPARD, M C; LUNCEFORD, C D

1965-02-01

198

Functional photoacoustic microscopy of pH  

PubMed Central

pH is a tightly regulated indicator of metabolic activity. In mammalian systems, an imbalance of pH regulation may result from or result in serious illness. In this paper, we report photoacoustic microscopy (PAM) of a commercially available pH-sensitive fluorescent dye (SNARF-5F carboxylic acid) in tissue phantoms. We demonstrated that PAM is capable of pH imaging in absolute values at tissue depths of up to 2.0 mm, greater than possible with other forms of optical microscopy.

Chatni, Muhammad Rameez; Yao, Junjie; Danielli, Amos; Favazza, Christopher P.; Maslov, Konstantin I.; Wang, Lihong V.

2011-01-01

199

Colorimetric Determination of pH.  

ERIC Educational Resources Information Center

Presented is an activity in which the pH of a solution can be quantitatively measured using a spectrophotometer. The theory, experimental details, sample preparation and selection, instrumentation, and results are discussed. (CW)

Tucker, Sheryl; And Others

1989-01-01

200

Mary Fennell, PhD Chair  

Cancer.gov

NCI Community Cancer Centers Program Evaluation Oversight Committee Roster CHAIR Mary Fennell, Ph.D. Chair, Department of Sociology and Community Health Brown University Box 1916, 211 Maxcy Hall 112 George Street Providence, RI 02912

201

Paul Pinsky, PhD, MPH  

Cancer.gov

Division of Cancer Prevention Staff Paul Pinsky, PhD, MPH Acting ChiefEarly Detection Research Group Location Division of Cancer PreventionNational Cancer Institute9609 Medical Center Drive, Room 5E444 Rockville, MD 20850 Phone

202

Aqueous-Solution pH Scales  

Microsoft Academic Search

The parallel existence of two forms of pH scale is considered, which is unique for the international metrological community. The basic advantages and shortcomings are considered for the multireference NIST scale and the single-reference BSI one.

O. V. Karpov; I. I. Maksimov; A. L. Seifer

2000-01-01

203

Effective endogenous gene silencing mediated by pH responsive peptides proceeds via multiple pathways  

PubMed Central

Cationic amphipathic histidine rich peptides possess high plasmid DNA and siRNA delivery capabilities. To further understand the pH responsive siRNA delivery process and evaluate the capabilities of such peptides we have investigated their ability to mediate specific silencing of endogenous GAPDH gene activity in MCF-7 and A549 cells and compared this with plasmid DNA delivery. A substantial and selective reduction of both GAPDH activity and expression was achieved using pH responsive peptide vectors, which compared favourably with that mediated by commercially available non-viral vectors in terms of efficacy and toxicity. Furthermore, by comparing the efficacy of both gene delivery and silencing mediated by a series of such peptides, their sensitivities to known inhibitors of endocytotic processes, and their route of uptake via confocal live cell imaging, we show that both plasmid DNA and siRNA are internalised via endocytosis. However siRNA entry facilitated by LAH4-L1, proceeds via a cholesterol dependent mechanism, in contrast to DNA transfer which is associated with clathrin dependent endocytosis. Furthermore, using peptides that respond at increasingly acidic pH, we demonstrate that the route of entry for the siRNA that ultimately mediates silencing is peptide specific and while some pH responsive peptides promote the escape of labelled siRNA from endosomes, others may promote entry via alternative mechanisms.

Lam, Jenny. K.W.; Liang, Wanling; Lan, Yun; Chaudhuri, Poulami; Chow, Michael Y.T.; Witt, Katarzyna; Kudsiova, Laila; Mason, A. James

2012-01-01

204

Predicting ultimate tensile and bending strengths of three finger-jointed tropical African hardwoods using acoustic emissions  

Microsoft Academic Search

The acoustic emissions behaviour of finger-joints from three tropical African hardwoods, Obeche (Triplochiton scleroxylon), Makore (Tieghemella heckelii) and Moabi (Baillonella toxisperma) were examined with a view to establishing their potential usefulness for non-destructively predicting ultimate tensile and bending strengths. Stress at first acoustic emission event-count as well as the cumulative event-count at 80 percent of mean failure stress and the

J. Ayarkwa; Y. Hirashima; K. Ando; Y. Sasaki

2000-01-01

205

Effect of Strain Rate on Cathodic Reaction During Stress Corrosion Cracking of X70 Pipeline Steel in a Near-Neutral pH Solution  

Microsoft Academic Search

The effect of strain rate on cathodic reactions of X70 pipeline steel during stress corrosion cracking in a near-neutral pH\\u000a solution was investigated by electrochemical impedance spectroscope and potentiodynamic polarization curve measurements as\\u000a well as slow strain rate tests. A local additional potential model was used to understand mechanistically the role of strain\\u000a rate in electrochemical cathodic reaction. It was

Z. Y. Liu; X. G. Li; Y. F. Cheng

206

MRF with adjustable pH  

NASA Astrophysics Data System (ADS)

Deterministic final polishing of high precision optics using sub-aperture processing with magnetorheological finishing (MRF) is an accepted practice throughout the world. A wide variety of materials can be successfully worked with aqueous (pH 10), magnetorheological (MR) fluids, using magnetic carbonyl iron (CI) and either ceria or nanodiamond nonmagnetic abrasives. Polycrystalline materials like zinc sulfide (ZnS) and zinc selenide (ZnSe) are difficult to polish at pH 10 with MRF, due to their grain size and the relatively low stiffness of the MR fluid lap. If microns of material are removed, the grain structure of the material begins to appear. In 2005, Kozhinova et al. (Appl. Opt. 44 4671-4677) demonstrated that lowering pH could improve MRF of ZnS. However, magnetic CI particle corrosion rendered their low pH approach unstable and unsuitable for commercial implementation. In 2009, Shafrir et al. described a sol-gel coating process for manufacturing a zirconia-coated CI particle that protects the magnetic core from aqueous corrosion (Appl. Opt .48 6797-6810). The coating process produces free nanozirconia polishing abrasives during the coating procedure, thereby creating an MR polishing powder that is "self-charged" with the polishing abrasive. By simply adding water, it was possible to polish optical glasses and ceramics with good stability at pH 8 for three weeks. The development of a corrosion resistant, MR polishing powder, opens up the possibility for polishing additional materials, wherein the pH may be adjusted to optimize effectiveness. In this paper we describe the CI coating process, the characterization of the coated powder, and procedures for making stable MR fluids with adjustable pH, giving polishing results for a variety of optical glasses and crystalline ceramics.

Jacobs, Stephen D.

2011-09-01

207

POTENSI KURKUMIN SEBAGAI PENUNJUK pH SEMULAJADI UNTUK PEMBANGUNAN SENSOR OPTIK pH  

Microsoft Academic Search

The potential of curcumin reagent as a natural pH indicator for the development of an optical pH sensor was discussed in this study. Curcumin has been chosen because it has never been reported before for use in the development of an optical pH sensor. Curcumin is a colouring constituent of tumeric that giving yellow pigmentation. Curcumin showed clear colour changes

Rosmawani Mohammad; Musa Ahmad; Jamaluddin Mohd Daud

2007-01-01

208

Novel optical pH sensor for high and low pH values  

Microsoft Academic Search

The development of an optical pH sensor based on immobilization of mixture of two dyes on a triacetylcellulose membrane is described. The sensor has a useful pH range at low and high pH values, where glass electrodes show acidic and alkaline errors, respectively. Application of a back-propagation artificial neural network (ANN) model extends the measuring range of the proposed optode

Afsaneh Safavi; Mozhgan Bagheri

2003-01-01

209

Ruminal pH regulation and nutritional consequences of low pH  

Microsoft Academic Search

Volatile fatty acids (VFA) and lactic acid can build up in the rumen and reduce ruminal pH. Low ruminal pH for prolonged periods each day can affect feed intake, microbial metabolism and feed digestion, and has also been related to inflammation, diarrhea and milk fat depression. This paper considers aspects of pH regulation, as well as the effects of ruminal

J. Dijkstra; J. L. Ellis; E. Kebreab; A. B. Strathe; S. Lopez; A. Bannink

2012-01-01

210

PhET Simulation: Build An Atom  

NSDL National Science Digital Library

This simulation is designed to help learners visualize atomic structure, as they drag protons, neutrons, and electrons to construct an atom. As particles are moved into place in the nucleus or the electron orbits, the simulation automatically displays the net charge, mass number, atomic symbol, and name of the element. After practicing with atom-building, users can test their skills against the clock in a game with four levels of increasing difficulty. See Related Materials for a lesson plan and student guide developed by the PhET project specifically for use with Build An Atom. The atom building simulation, which must be open and displayed to complete this activity, is available from PhET at: Build An Atom. This lesson is part of PhET (Physics Education Technology Project), a large collection of free interactive simulations for science education.

211

PhET Teacher Activities: Modeling Isotopes  

NSDL National Science Digital Library

This lesson plan was created specifically to accompany the PhET simulation "Isotopes and Atomic Mass". Appropriate for grades 7-10, it provides explicit guidance for modeling atoms and their variant isotopes. As students add neutrons to the nuclear model, they can see a relationship between the stability of the atom and its abundance in nature. The model makes it easy to visualize that atoms of one element always have the same number of protons, but can have various numbers of neutrons. It will help students differentiate Atomic Number (number of protons in the nucleus) from Mass Number (the number of protons and neutrons. The isotope simulation, which must be open and displayed to complete this activity, is available from PhET at: Isotopes and Atomic Mass. This lesson is part of PhET (Physics Education Technology Project), a large collection of free interactive simulations for science education.

Marrero, Robert

2011-07-18

212

CRCHD Principal Investigator: Campbell, Janis, Ph.D.  

Cancer.gov

CRCHD Principal Investigator: Campbell, Janis, Ph.D.  Back to CRCHD Ongoing Research CNP Project Listing Janis Campbell, Ph.D. CNP Project Listing CNP Pilot Projects Project Investigator Biography Campbell, Janis, Ph.D. University of

213

CRCHD Principal Investigator: Paula A. Espinoza, Ph.D.  

Cancer.gov

CRCHD Principal Investigator: Paula A. Espinoza, Ph.D.  Back to CRCHD Ongoing Research CNP Project Listing Paula A. Espinoza, Ph.D. CNP Project Listing CNP Pilot Projects Project Investigator Biography Paula A. Espinoza, Ph.D. University

214

PhET Simulations: Quantum Phenomena  

NSDL National Science Digital Library

This is a collection of simulations from the PhET project in Quantum and Modern Physics. The simulations cover a range of topics including the photoelectric effect, wave interference, lasers, blackbody radiation, tunneling, the Stern-Gerlach experiment, nuclear physics, and applications of quantum mechanics. Each simulation provides a user interface that allows learners to explore the physical systems. These resources are part of the PhET project that has created a large collection of research-validated physics, chemistry, and math simulations.

Project, Physics E.

2008-07-13

215

PhEt - Physics Education Technology  

NSDL National Science Digital Library

PhEt is a free website of over sixty interactive simulations that provides opportunities for students to learn physics and chemistry through exploration and virtual labs. A browsable teacher-contributed collection of homework assignments, lectures, activities, and concept questions is available. Additional contributions designed to be used in conjunction with the PhET simulations may be submitted. Simulations can be run in three different ways: on line, by downloading one or more simulations at a time, or by a download of the entire website to your computer. Many simulations have been translated into different languages.

216

Differential genotoxicity of diphenyl diselenide (PhSe)2 and diphenyl ditelluride (PhTe)2.  

PubMed

Organoselenium compounds have been pointed out as therapeutic agents. In contrast, the potential therapeutic aspects of tellurides have not yet been demonstrated. The present study evaluated the comparative toxicological effects of diphenyl diselenide (PhSe)2 and diphenyl ditelluride (PhTe)2 in mice after in vivo administration. Genotoxicity (as determined by comet assay) and mutagenicicity were used as end-points of toxicity. Subcutaneous administration of high doses of (PhSe)2 or (PhTe)2 (500 µmol/kg) caused distinct genotoxicity in mice. (PhSe)2 significantly decreased the DNA damage index after 48 and 96 h of its injection (p < 0.05). In contrast, (PhTe) caused a significant increase in DNA damage (p < 0.05) after 48 and 96 h of intoxication. (PhSe)2 did not cause mutagenicity but (PhTe)2 increased the micronuclei frequency, indicating its mutagenic potential. The present study demonstrated that acute in vivo exposure to ditelluride caused genotoxicity in mice, which may be associated with pro-oxidant effects of diphenyl ditelluride. In addition, the use of this compound and possibly other related tellurides must be carefully controlled. PMID:24711962

Meinerz, Daiane Francine; Allebrandt, Josiane; Mariano, Douglas O C; Waczuk, Emily P; Soares, Felix Antunes; Hassan, Waseem; Rocha, João Batista T

2014-01-01

217

The Utilization of Spin Polarized Photoelectron Spectroscopy as a Probe of Electron Correlation with an Ultimate Goal of Pu  

SciTech Connect

We are developing the technique of spin-polarized photoelectron spectroscopy as a probe of electron correlation with the ultimate goal of resolving the Pu electronic structure controversy. Over the last several years, we have demonstrated the utility of spin polarized photoelectron spectroscopy for determining the fine details of the electronic structure in complex systems such as those shown in this paper. Various recent publications have addressed the ongoing question of the nature of the Pu electronic structure. One possibility is the existence of a Kondo-like shielding of the 5f electrons. We propose that spin resolved PES is the most promising approach to resolving this question. (authors)

Tobin, J.G.; Yu, S.W.; Chung, B.W. [LLNL, Livermore, CA, 94550 (United States); Morton, S.A. [LLNL, Livermore, CA, 94550 (United States)]|[LBNL, Berkeley, CA, 94720 (United States); Komesu, T.; Waddill, G.D. [Missouri University of Science and Technology, Rolla, MO, 65401 (United States)

2008-07-01

218

pH & Rate of Enzymatic Reactions.  

ERIC Educational Resources Information Center

A quantitative and inexpensive way to measure the rate of enzymatic reaction is provided. The effects of different pH levels on the reaction rate of an enzyme from yeast are investigated and the results graphed. Background information, a list of needed materials, directions for preparing solutions, procedure, and results and discussion are…

Clariana, Roy B.

1991-01-01

219

Effect of Ph on Human Mycoplasma Strains.  

National Technical Information Service (NTIS)

The optimal reaction of culture media for the cultivation of T-strain Mycoplasma of human origin was investigated. By use of a recently modified tryptic digest medium, the optimal reaction in either agar or fluid medium was found to be pH 6.0. In contrast...

M. C. Shepard C. D. Lunceford

1964-01-01

220

The Economic Contribution of PhDs  

ERIC Educational Resources Information Center

This paper looks at what the value of a doctorate is, both to employers in particular and to society and the economy at large. Given the emphasis many universities and funding agencies/governments are putting upon the development of PhD programmes, this is an issue deserving attention. The paper tries to show how two separate but interrelated…

Casey, Bernard H.

2009-01-01

221

Monitoring fetal pH by telemetry  

NASA Technical Reports Server (NTRS)

Telemetry unit has been developed for possible use in measuring scalp-tissue pH and heart rate of unborn infant. Unit radius data to receiver as much as 50 ft. away. Application exists during hours just prior to childbirth to give warning of problems that might require cesarean delivery.

Blum, A.; Donahoe, T.; Jhabvala, M. D.; Ryan, W.

1980-01-01

222

First-Principles pH Theory  

NASA Astrophysics Data System (ADS)

Despite being one of the most important macroscopic measures and a long history even before the quantum mechanics, the concept of pH has rarely been mentioned in microscopic theories, nor being incorporated computationally into first-principles theory of aqueous solutions. Here, we formulate a theory for the pH dependence of solution formation energy by introducing the proton chemical potential as the microscopic counterpart of pH in atomistic solution models. Within the theory, the general acid-base chemistry can be cast in a simple pictorial representation. We adopt density-functional molecular dynamics to demonstrate the usefulness of the method by studying a number of solution systems including water, small solute molecules such as NH3 and HCOOH, and more complex amino acids with several functional groups. For pure water, we calculated the auto- ionization constant to be 13.2 with a 95 % accuracy. For other solutes, the calculated dissociation constants, i.e., the so- called pKa, are also in reasonable agreement with experiments. Our first-principles pH theory can be readily applied to broad solution chemistry problems such as redox reactions.

Kim, Yong-Hyun; Zhang, S. B.

2006-03-01

223

The Ph.D. Value Proposition  

ERIC Educational Resources Information Center

Atlanta University launched its doctor of arts in humanities (DAH) programs almost 40 years ago, and, since the 1988 merger with Clark College, Clark Atlanta University has continued to award the degrees. This fall, for the first time, its students will be able to earn Ph.D.s in humanities instead. In DAH programs around the country, there's been…

Cooper, Kenneth J.

2012-01-01

224

Teaching Physics Using PhET Simulations  

ERIC Educational Resources Information Center

PhET Interactive Simulations (sims) are now being widely used in teaching physics and chemistry. Sims can be used in many different educational settings, including lecture, individual or small group inquiry activities, homework, and lab. Here we will highlight a few ways to use them in teaching, based on our research and experiences using them in…

Wieman, C. E.; Adams, W. K.; Loeblein, P.; Perkins, K. K.

2010-01-01

225

Endoscopic thoracic sympathetic block by clipping for palmar and axillary hyperhidrosis in children and adolescents  

Microsoft Academic Search

.   Endoscopic thoracic sympathectomy or sympathicotomy is a safe and effective method of treating primary hyperhidrosis (PH),\\u000a but postoperative compensatory sweating may be a problem. There are few reports of sympathetic blockade by clipping for PH.\\u000a We present our experience of endoscopic thoracic sympathetic block (ETSB) by clipping in treating palmar (PAH) and axillary\\u000a hyperhidrosis (AH) in children and adolescents.

Torng-Sen Lin; Ling-Chu Huang; Nai-Phon Wang; Cheng-Chuan Chang

2001-01-01

226

New improvements of the extended minimum cost flow phase unwrapping for processing multitemporal full resolution interferograms  

Microsoft Academic Search

We present an efficient space-time phase unwrapping (PhU) algorithm allowing us to analyze sequences of multitemporal full resolution differential Synthetic Aperture Radar (SAR) interferograms for the generation of deformation time-series. The core of the proposed technique is represented by the extended minimum cost flow (EMCF) PhU algorithm. Our method is based on a joint analysis of the spatial and temporal

A Pepe; M Bonano; Y Yang; M Manunta; R Lanari

2011-01-01

227

Dose-dependent effects of an immune challenge at both ultimate and proximate levels in Drosophila melanogaster.  

PubMed

Immune responses are highly dynamic. The magnitude and efficiency of an immune response to a pathogen can change markedly across individuals, and such changes may be influenced by variance in a range of intrinsic (e.g. age, genotype, sex) and external (e.g. abiotic stress, pathogen identity, strain) factors. Life history theory predicts that up-regulation of the immune system will come at a physiological cost, and studies have confirmed that increased investment in immunity can reduce reproductive output and survival. Furthermore, males and females often have divergent reproductive strategies, and this might drive the evolution of sex-specific life history trade-offs involving immunity, and sexual dimorphism in immune responses per se. Here, we employ an experiment design to elucidate dose-dependent and sex-specific responses to exposure to a nonpathogenic immune elicitor at two scales - the 'ultimate' life history and the underlying 'proximate' immune level in Drosophila melanogaster. We found dose-dependent effects of immune challenges on both male and female components of reproductive success, but not on survival, as well as a response in antimicrobial activity. These results indicate that even in the absence of the direct pathogenic effects that are associated with actual disease, individual life histories respond to a perceived immune challenge - but with the magnitude of this response being contingent on the initial dose of exposure. Furthermore, the results indicate that immune responses at the ultimate life history level may indeed reflect underlying processes that occur at the proximate level. PMID:24731072

Nystrand, M; Dowling, D K

2014-05-01

228

Water Droplet Erosion Behavior of High-Power Diode Laser Treated 17Cr4Ni PH Stainless Steel  

NASA Astrophysics Data System (ADS)

This article deals with water droplet erosion (WDE) behavior of high-power diode laser (HPDL) treated 17Cr4Ni PH stainless steel. After HPDL treatment, the water droplet erosion resistance (WDER) of 17Cr4Ni PH stainless steel has not improved. The main reason is the surface hardness, which has not improved after HPDL treatment though the microstructure has become much finer. On the other hand, precipitation hardening of the alloy at 490°C for 3 h has resulted in improved WDER more than twice. This is because of its increased microhardness and improved modified ultimate resilience (MUR), and formation of fine grained microstructure. The WDER has been correlated with MUR, a single mechanical property, based upon microhardness, ultimate tensile strength, and Young's modulus. WDERs of HPDL treated, untreated, and precipitation hardened 17Cr4Ni PH stainless steel samples were determined using a WDE test facility as per ASTM G73-1978. The WDE damage mechanism, compared on the basis of MUR and scanning electron micrographs, is discussed and reported in this article.

Mann, B. S.

2014-05-01

229

Effect of electrolyte pH on CIEF with narrow pH range ampholytes.  

PubMed

CIEF of components following sequential injection of ampholytes and the sample zone offers unique advantages for analysis. The most important one of these is the efficient separation of amphoteric compounds having pIs outside the pH range of the ampholytes applied, but the resolution of the components can be increased by an adequate setup in the injection protocol. In this study, the effect of the pH of the anolyte and catholyte on the selectivity and speed of the isoelectric focusing was investigated. Changes in the pH values significantly influenced the resolution and the length of the pH gradient, while changes in the charge state of components were also observed. Three ampholyte solutions (from different suppliers) covering only two pH units were used for the analyses of substituted nitrophenol dyes in uncoated capillary. With appropriate setup, the components, with pIs not covered by the ampholyte pH range, migrated in charged state outside the pH gradient. This phenomenon is preferable for coupling isoelectric focusing to MS detection, by evading the undesirable ion suppression effect of ampholytes. PMID:23086725

Páger, Csilla; Vargová, Andrea; Takácsi-Nagy, Anna; Dörnyei, Ágnes; Kilár, Ferenc

2012-11-01

230

Optical pH sensor for physiological pH measurement  

NASA Astrophysics Data System (ADS)

A miniature optical sensor based on the fluorescent indicator, 8-hydroxyl-1,3,6-pyrene trisulfonic Acid Trisodium Salt (HOPSA), was developed for physiological pH measurement. Dowex-1 strongly basic anion exchange resin was used as a medium to immobilize the indicator on the end of an optical fiber to form a pH sensing layer. Polyetherurethane was dip- coated onto the sensing layer as the permeable membrane for H+. The properties of the sensor were assessed and found to be suitable for monitoring physiological pH values.

Zhang, Sifu; Rolfe, Peter; Wickramasinghe, Yapa A.

1994-02-01

231

Coordination complexes of Ph?Sb²? and Ph?Bi²?: beyond pnictonium cations.  

PubMed

The syntheses of salts containing ligand-stabilized Ph3Sb(2+) and Ph3Bi(2+) dications have been realized by in?situ formation of Ph3Pn(OTf)2 (Pn=Sb or Bi) and subsequent reaction with OPPh3, dmap and bipy. The solid-state structures demonstrate diversity imposed by the steric demands and nature of the ligands. The synthetic method has the potential for broad application enabling widespread development of the coordination chemistry for Pn(V) acceptors. PMID:24616180

Robertson, Alasdair P M; Burford, Neil; McDonald, Robert; Ferguson, Michael J

2014-03-24

232

The ultimate high tide  

SciTech Connect

This paper discusses the possible coastal impacts of a rise in sea level. Control measures that are available to coastal communities are emphasized, including pumping of seawater into the ground, replenishing beach sand, protection or moving of potable-water intakes, elevating roadways, and building dikes. Economics will determine which, if any, measures are reasonable at a particular site. There is an upward trend in the mean CO{sub 2} concentration and predictions about the greenhouse effect are creating a rising tide of concern.

Dean, R.G. (Florida Dept. of Natural Resources, Tallahassee (USA))

1990-01-01

233

The Ultimate Private Observatory  

NASA Astrophysics Data System (ADS)

An amateur astronomer from Washington Parish, Southeast Louisiana, USA has designed and built an amazing observatory. It is not only an astronomical observatory, but a home theater, and tornado shelter designed to take a direct hit from an F5 tornado. The facility is fully equipped and automated, with a hydraulically driven roof that weighs 20,571 lbs., which lifts up, then rolls away to the end of the tracks. This leaves the user sitting inside of four 14-foot high walls open to the night sky. It has two premium quality telescopes for viewing deep space and objects inside the solar system. The chair that the observer sits on is also hydraulically driven.

Aymond, J.

2009-03-01

234

The Ultimate Upgrade Guide  

NSDL National Science Digital Library

Computers, as everyone knows, seems to get cheaper every day. Many users find that they can now buy twice the computer for half the money they spent a few years ago. A brand new computer, however, may not be the only answer for users wishing for better performance or simply a level playing field, as prices for computer components have kept pace with whole computers. This new report from PC Magazine Online is designed to help users decide if and how to upgrade their present hardware to get a few more years out of their original investment. The report is composed of three main sections (Core Components, Multimedia, and Internet and I/O Connections), each of which analyzes the merits and prices of various upgrades, and offers tips and instructions for installation.

235

Science and Ultimate Reality  

NASA Astrophysics Data System (ADS)

This preview of the future of physics comprises contributions from recognized authorities inspired by the pioneering work of John Wheeler. Quantum theory represents a unifying theme within the book, as it relates to the topics of the nature of physical reality, cosmic inflation, the arrow of time, models of the universe, superstrings, quantum gravity and cosmology. Attempts to formulate a final unification theory of physics are also considered, along with the existence of hidden dimensions of space, hidden cosmic matter, and the strange world of quantum technology. John Archibald Wheeler is one of the most influential scientists of the twentieth century. His extraordinary career has spanned momentous advances in physics, from the birth of the nuclear age to the conception of the quantum computer. Famous for coining the term "black hole," Professor Wheeler helped lay the foundations for the rebirth of gravitation as a mainstream branch of science, triggering the explosive growth in astrophysics and cosmology that followed. His early contributions to physics include the S matrix, the theory of nuclear rotation (with Edward Teller), the theory of nuclear fission (with Niels Bohr), action-at-a-distance electrodynamics (with Richard Feynman), positrons as backward-in-time electrons, the universal Fermi interaction (with Jayme Tiomno), muonic atoms, and the collective model of the nucleus. His inimitable style of thinking, quirky wit, and love of the bizarre have inspired generations of physicists.

Barrow, John D.; Davies, Paul C. W.; Harper, Charles L., Jr.

2004-06-01

236

Ultimate Cary Grant Pages  

NSDL National Science Digital Library

Maintained and developed by Debbie Dunlap, a devoted fan, this site pays homage to Cary Grant (whose real name was the slightly less marquee-friendly, Archibald Leach), one of Hollywood's leading men during the 20th century. The site provides a host of material about Grant, his films, and his life, including a filmography, movie reviews, a photo gallery, a sound gallery, and links to old radio shows in which Cary Grant appeared. The sound gallery is an excellent part of the site, as visitors can listen to audio clips from Grant vehicles like North by Northwest, Arsenic and Old Lace, and Charade. Visitors will learn quite a bit about Cary Grant from the site, including the fact that he never won an Academy Award for his acting, although he was awarded an honorary Oscar in 1970 for his life's work.

237

The ultimate curse.  

PubMed Central

This paper tells the story of a doctor in a vegetative state. The approach towards him is quite different from that towards a common patient. The other physicians cannot deal with this situation with the necessary open mind.

Crisci, C

1995-01-01

238

Multitechnique investigation of the pH dependence of phosphate induced transformations of ZnO nanoparticles.  

PubMed

In order to properly evaluate the ecological and human health risks of ZnO manufactured nanomaterials (MNMs) released to the environment, it is critical to understand the likely transformation products in various environments, such as soils, surface and ground waters, and wastewater treatment processes. To address this knowledge gap, we examined the transformation of 30 nm ZnO MNMs in the presence of different concentrations of phosphate as a function of time and pH using a variety of orthogonal analytical techniques. The data reveal that ZnO MNMs react with phosphate at various concentrations and transform into two distinct morphological/structural phases: a micrometer scale crystalline zinc phosphate phase (hopeite-like) and a nanoscale phase that likely consists of a ZnO core with an amorphous Zn3(PO4)2 shell. The P species composition was also pH dependent, with 82% occurring as hopeite-like P at pH 6 while only 15% occurred as hopeite-like P at pH 8. These results highlight how reactions of ZnO MNMs with phosphate are influenced by environmental variables, including pH, and may ultimately result in structurally and morphologically heterogeneous end products. PMID:24693856

Rathnayake, Sewwandi; Unrine, Jason M; Judy, Jonathan; Miller, Anne-Frances; Rao, William; Bertsch, Paul M

2014-05-01

239

Re-envisioning the PhD  

NSDL National Science Digital Library

This new site, sponsored by the Pew Charitable Trusts, is home to the Re-envisioning the PhD project, which is tasked with investigating change in doctoral education, in particular, helping to expand the career choices available to PhD students. In the Re-envisioning Project Resources section, visitors will find conference materials, recommendations from studies, summaries of interviews, a bibliography, career resources, and more. The Promising Practices section contains information on the different ways in which groups (universities, associations, organizations, and more) are responding to concerns about doctoral education. The other two main sections of the site, National/ International Resources and News and Updates contain links to even more resources, studies, current news, related projects, and more.

2001-01-01

240

PhET Simulation: States of Matter  

NSDL National Science Digital Library

This simulation helps learners visualize how molecules behave in solids, liquids, and gases. Add or remove heat and watch the motion of the molecules as they change phase. Push the pump and change the volume of matter in the closed container and watch the pressure gauge respond. More advanced students can compare the potential energy graphs for neon, argon, oxygen, and water -- which all have different interaction potential. Editor's Note: This particular activity would be well paired with the PhET "Gas Properties" simulation, which goes into more depth to explore the behavior of gas molecules in a closed container. Together, the simulations promote understanding of gas laws, states of matter, phase change, and kinetic theory. See Related Materials for a link to an exemplary lesson plan developed to accompany "States of Matter" simulation. This item is part of a larger collection of simulations developed by the Physics Education Technology project (PhET).

2011-07-18

241

Highlights From PhUn Week 2007  

NSDL National Science Digital Library

This is an article from The Physiologist. "More than 100 APS physiologists volunteered their time in reaching out to more than 3000 students last November during Physiology Understanding Week (PhUn Week), the APS member-based annual outreach program to local area K-12 schools (http://www.PhUnWeek.org). APS members partnered with more than 70 teachers and science educators from across the nation to develop engaging classroom or campus presentations for students at all grade levels, from day care through twelfth grades. The following vignettes are only a few samples of the excitement and fun generated by the focus on the physiology of health and exercise during the first week in November. All events with the primary APS member and lead teacher coordinators are listed in Table 1.".

2008-02-01

242

Nanometer optical fiber pH sensor  

Microsoft Academic Search

A thousandfold miniaturization of immobilized optical fiber sensors has been achieved by a near-field optical technique. This technology is based on nanofabricated optical fiber tips and near-field photoinitiated polymerization. Submicrometer pH sensors have been prepared by attaching a copolymer covalently to a silanized fiber tip surface. The sensors have demonstrated their high spatial resolving ability, excellent detection limit (zeptomoles), very

Raoul Kopelman; Weihong Tan; Zhong-You Shi

1993-01-01

243

Cellulose based bulk pH optomembranes  

Microsoft Academic Search

The paper presents an efficient technique for the preparation of pH-sensitive bulk optomembranes for fiber optic chemical sensors (FOCS). The method is based on the physical entrapment of the reagent molecules in the bulk of cellulose acetate membranes. The durable immobilization of a pH indicator is achieved by the addition of an appropriate ion-balance reagent to the cellulose matrix. The

Wojciech Wróblewski; Ewa Ro?niecka; Artur Dybko; Zbigniew Brzózka

1998-01-01

244

PhET: Energy Skate Park  

NSDL National Science Digital Library

Students explore conservation of energy by building ramps, jumps, and tracks for a skateboarder. The relationship of kinetic and potential energy becomes clear through charts of energy vs. time and energy vs. position. The skater can be transported to different planets to illustrate the effects of changing the gravitational constant. This item is part of a larger collection of simulations developed by the Physics Education Technology project (PhET). The simulations are animated, interactive, and game-like environments.

2009-11-25

245

PhET Simulation: Balloons & Buoyancy  

NSDL National Science Digital Library

This applet experiments with a helium balloon, a hot air balloon, or a rigid sphere filled with different gases. The user can discover what makes some balloons float and others sink. Teaching ideas and activities are included. The direct link to the simulation is given as a mirror URL. This is part of a larger collection developed by the Physics Education Technology project (PhET).

2008-07-15

246

Hua Zhang, PhD, Biologist  

Cancer.gov

Hua Zhang received his Bachelor of Medicine at Shanghai Second Medical University then a PhD in Microbiology and Immunology at the University of Arizona. Dr. Zhang has had a longstanding interest in the development of immunotherapies for cancer. He first postdoctoral fellowship was in the Department of Chemical Engineering at the University of Texas where he worked to develop scFv antibody derived biologics (Zhang et al, Cancer Research 1995) and then he subsequently studied with Dr.

247

STM Studies of Mn12-Ph  

NASA Astrophysics Data System (ADS)

Mn12-Ph displays tunneling of quantized magnetization below 3K. In other Mn12 ligand variants this magnetic behavior can alter the electronic behavior of the molecule making them good candidates for a molecular logic gate or q-bit. Mn12O12(C6H5COO)16 (referred to as Mn12-Ph) has a Mn12 core with 16 Phenyl ligands and is deposited via spray injection onto surfaces of highly oriented pyrolytic graphite (HOPG) and other surfaces. We report Mn12-Ph in isolation, resembling single molecules with metallic core atoms and organic outer ligands. The local tunneling current observed within the molecular structure shows a strong bias voltage dependence, which is distinct from that of the surface. Further, evidence of internal inhomogeneity in the local density of states has been observed with high spatial resolution, and this inhomogeneity appears to be due to localized metallic behavior. These results facilitate magneto-metric studies of single molecule magnets in isolation. As compared to bulk crystal studies, our experiments allow the specific investigation of atomic sites in individual molecules.

Reaves, K.; Kim, K.; Iwaya, K.; Hitosugi, T.; Zhao, H.; Dunbar, K. R.; Katzgraber, H. G.; Teizer, W.

2013-03-01

248

Magnetic Optical Sensor Particles for pH Measurement  

Microsoft Academic Search

Magnetic optical sensor particles (MOSePs) in nanometer scale for pH measurement were synthesized and characterized. The measurement of pH is based on a ratiometric evaluation of the fluorescence of a pH-sensitive indicator dye (N-fluorescein-acrylamide) and a reference dye (a rhodamine derivative) which is not affected by pH. Measurement of pH in aqueous media in the range of pH 5 to

Elisabeth Scheucher; Günter Mistlberger; Ingo Klimant

2010-01-01

249

A wireless passive pH sensor based on pH electrode potential measurement  

Microsoft Academic Search

We present a wireless coupled-coil passive pH sensor for high-resolution remote pH monitoring. The sensor is based on a passive LC coil resonator whose resonant frequency is monitored remotely by measuring the impedance of an interrogator coil coupled to the sensor coil. The sensor consists of an inductive coil connected in parallel with a varactor (voltage dependent capacitor) and a

S. Bhadra; G. E. Bridges; D. J. Thomson; M. S. Freund

2010-01-01

250

Optical pH sensor for physiological pH measurement  

Microsoft Academic Search

A miniature optical sensor based on the fluorescent indicator, 8-hydroxyl-1,3,6-pyrene trisulfonic Acid Trisodium Salt (HOPSA), was developed for physiological pH measurement. Dowex-1 strongly basic anion exchange resin was used as a medium to immobilize the indicator on the end of an optical fiber to form a pH sensing layer. Polyetherurethane was dip- coated onto the sensing layer as the permeable

Sifu Zhang; Peter Rolfe; Yapa A. Wickramasinghe

1994-01-01

251

PhD job market: professional trajectories and incentives during the PhD  

Microsoft Academic Search

It is becoming more and more difficult for PhD graduates to find a job corresponding to their qualifications. Stephan and Levin have shown that this situation weakens the implicit contract between PhD students (or post-doc) and the research team in which they are doing their research. This weakness of the implicit contract may slow down scientific production because of the

V. Mangematin

2000-01-01

252

Effect of cooling rate on eutectic cell count, grain size, microstructure, and ultimate tensile strength of hypoeutectic cast iron  

SciTech Connect

This article describes a series of microstructural and strength studies performed on hypoeutectic cast iron, which was sand cast using a variety of end chills (metallic, nonmetallic, water-cooled, and subzero, respectively). The effects of cooling rate on the eutectic cell count (ECC), grain size, and the ultimate tensile strength (UTS) were evaluated. Attempts were also made to explain these effects and to correlate the UTS with ECC. It was found that subzero chilled and water-cool, chilled cast iron exhibit severe undercooling compared to normal sand cast iron. It was concluded from this investigation that nucleation conditions are completely altered but growth conditions prevail as usual. Therefore, undercooling during solidification is considered to be responsible for variation in ECC, grain size, and microstructure, and tensile strength.

Hemanth, J.; Rao, K.V.S. (Siddaganga Inst. of Tech., Karnataka (India). Dept. of Mechanical Engineering)

1999-08-01

253

Towards the Artsutanov's dream of the space elevator: The ultimate design of a 35 GPa strong tether thanks to graphene  

NASA Astrophysics Data System (ADS)

In this paper, we have evaluated the strength of a graphene/nanotube bundle considering the two possible failure mechanisms, i.e. intrinsic fracture or sliding. We have accordingly proposed smart strengthening strategies, such as a flaw tolerant design and the nanotube self-collapse. The flaw tolerant design reduces the required strength whereas the self-collapse can increase the achievable strength. Only by coupling these complementary, and possibly other e.g. self-healing, smart strategies, the Artsutanov's dream of the space elevator could be realized. The ultimate design of a 35 GPa strong tether is thus proposed for the first time in this paper, thanks to graphene bundles and the numerous previous investigations performed by the author. Graphene bundles and composites, in which sliding is the current weakest link, are demonstrated to be two times stronger than their nanotube counterparts.

Pugno, Nicola M.

2013-02-01

254

Common and small molecules as the ultimate regulatory and effector mediators of antigen-specific transplantation reactions.  

PubMed

In spite of intensive research, the molecular basis of allograft and xenograft rejection still remains not fully understood. The acute rejection of an allograft is associated with the intragraft Th1 cytokine response, while tolerance of an allograft or xenograft rejection is accompanied by a higher production of the Th2 cytokines interleukin (IL)-4 and IL-10. Nevertheless, these cytokines are not the final regulatory and effector molecules mediating transplantation reactions. Data indicate that the functioning of common molecules with enzymatic activities, such are inducible nitric oxide synthase (iNOS), arginase, heme oxygenase-1 (HO-1) or indoleamine-2,3-dioxygenase (IDO), the bioavailability of their substrates (L-arginine, tryptophan, heme) and the cytotoxic and regulatory actions of their small gaseous products (NO, CO) can be the ultimate mechanisms responsible for effector or regulatory reactions. Using models of transplantation immunity and tolerance we show that T cell receptor-mediated recognition of allogeneic or xenogeneic antigens as well as the balance between immunity/tolerance induces distinct cytokine production profiles. The ratio between Th1 and Th2 cytokines efficiently regulates the expression of genes for common enzymes, such as iNOS, arginase, HO-1 and IDO. These enzymes may compete for substrates, such as L-arginine or tryptophan, and the final product of their activity are small molecules (NO, CO) displaying effector or regulatory functions of the immune system. Thus, it is suggested that in spite of the high immunological specificity of transplatation reaction, the ultimate players in regulatory and effector functions could be small and common molecules. PMID:24392309

Holan, Vladimir; Krulova, Magdalena

2013-12-24

255

Measuring the Ultimate Halo Mass of Galaxy Clusters: Redshifts and Mass Profiles from the Hectospec Cluster Survey (HeCS)  

NASA Astrophysics Data System (ADS)

The infall regions of galaxy clusters represent the largest gravitationally bound structures in a ?CDM universe. Measuring cluster mass profiles into the infall regions provides an estimate of the ultimate mass of these halos. We use the caustic technique to measure cluster mass profiles from galaxy redshifts obtained with the Hectospec Cluster Survey (HeCS), an extensive spectroscopic survey of galaxy clusters with MMT/Hectospec. We survey 58 clusters selected by X-ray flux at 0.1 < z < 0.3. The survey includes 22,680 unique MMT/Hectospec redshifts for individual galaxies; 10,145 of these galaxies are cluster members. For each cluster, we acquired high signal-to-noise spectra for ~200 cluster members and a comparable number of foreground/background galaxies. The cluster members trace out infall patterns around the clusters. The members define a very narrow red sequence. We demonstrate that the determination of velocity dispersion is insensitive to the inclusion of bluer members (a small fraction of the cluster population). We apply the caustic technique to define membership and estimate the mass profiles to large radii. The ultimate halo mass of clusters (the mass that remains bound in the far future of a ?CDM universe) is on average (1.99 ± 0.11)M 200, a new observational cosmological test in essential agreement with simulations. Summed profiles binned in M 200 and in LX demonstrate that the predicted Navarro-Frenk-White form of the density profile is a remarkably good representation of the data in agreement with weak lensing results extending to large radius. The concentration of these summed profiles is also consistent with theoretical predictions.

Rines, Kenneth; Geller, Margaret J.; Diaferio, Antonaldo; Kurtz, Michael J.

2013-04-01

256

Common and small molecules as the ultimate regulatory and effector mediators of antigen-specific transplantation reactions  

PubMed Central

In spite of intensive research, the molecular basis of allograft and xenograft rejection still remains not fully understood. The acute rejection of an allograft is associated with the intragraft Th1 cytokine response, while tolerance of an allograft or xenograft rejection is accompanied by a higher production of the Th2 cytokines interleukin (IL)-4 and IL-10. Nevertheless, these cytokines are not the final regulatory and effector molecules mediating transplantation reactions. Data indicate that the functioning of common molecules with enzymatic activities, such are inducible nitric oxide synthase (iNOS), arginase, heme oxygenase-1 (HO-1) or indoleamine-2,3-dioxygenase (IDO), the bioavailability of their substrates (L-arginine, tryptophan, heme) and the cytotoxic and regulatory actions of their small gaseous products (NO, CO) can be the ultimate mechanisms responsible for effector or regulatory reactions. Using models of transplantation immunity and tolerance we show that T cell receptor-mediated recognition of allogeneic or xenogeneic antigens as well as the balance between immunity/tolerance induces distinct cytokine production profiles. The ratio between Th1 and Th2 cytokines efficiently regulates the expression of genes for common enzymes, such as iNOS, arginase, HO-1 and IDO. These enzymes may compete for substrates, such as L-arginine or tryptophan, and the final product of their activity are small molecules (NO, CO) displaying effector or regulatory functions of the immune system. Thus, it is suggested that in spite of the high immunological specificity of transplatation reaction, the ultimate players in regulatory and effector functions could be small and common molecules.

Holan, Vladimir; Krulova, Magdalena

2013-01-01

257

Analysis at the sequence level of mutations induced by the ultimate carcinogen N-acetoxy-N-2-acetylaminofluorene  

PubMed Central

The covalent binding of an ultimate carcinogen to the DNA bases or phosphate groups creates a premutational lesion that in vivo is processed by the repair, replication and recombination enzymes, and eventually may be converted into a mutation. Being interested in the way that an initial premutational event is converted into a stable heritable mutation, we have sequenced stable mutations in a gene that has formed covalent adducts in vitro with N-acetoxy-N-2-acetylaminofluorene (N-AcO-AAF, a model for the ultimate metabolite of the rat liver carcinogen 2-acetylaminofluorene, AAF). In vivo studies have shown the mutagenicity of AAF and its derivatives in both bacterial and eukaryotic systems. N-AcO-AAF reacts in vitro with DNA leading mainly to the formation of a guanine adduct, N-2-(deoxyguanosin-8-yl)-acetylaminofluorene (80%) and to at least three minor adducts. Studies by our group showed that binding of N-AcO-AAF to DNA resulted in a local distortion of the DNA helix around the C-8 adduct (the insertion-denaturation model). We describe here the analysis of forward mutations induced in the tetracycline-resistance gene of pBR322 by directing the chemical reaction of the carcinogen to a small restriction fragment (BamHI-SalI) inside the antibiotic-resistance gene. Mutants are selected for ampicillin (Ap) resistance and tetracycline (Tc) sensitivity. The plasmid DNA of such mutants was analyzed for sequence changes in the fragment where the AAF binding had been directed. We show here that the mutations are mainly frameshifts involving GC base pairs and that certain base pairs (hotspots) are affected at high frequencies. ImagesFIGURE 3.

Fuchs, Robert P. P.; Schwartz, Nicole; Daune, Michel P.

1983-01-01

258

The influence of deposition solution pH and ionic strength on the quality of poly(N-isopropylacrylamide) microgel-based thin films and etalons.  

PubMed

Poly(N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgel-based thin films and etalons were fabricated via "painting" a pNIPAm-co-AAc microgel monolayer on a Au-coated substrate, followed by the deposition of another Au overlayer. Herein, in situ observation of how the pH and ionic strength (I.S.) of the painting solution influenced microgel deposition and, ultimately, the optical homogeneity and pH sensitivity of the etalon was carried out. It was shown that microgels closely pack on the Au substrate when they are deposited at pH 3.0, leading to a good optical homogeneity. Additionally, increasing the painting solution I.S. leads to a slight decrease in microgel packing density on the substrate, but enhances the ability of the microgel layer to swell, exhibiting thicker polymer layers when immersed in pH 3.0 solutions. When painting at pH 7.5, the optical homogeneity of the etalon is improved at the expense of swellability, exaggerated high I.S. We also determined the device's sensitivity to pH changes and found a maximum sensitivity when the microgels were deposited at pH 7.5 with an I.S. of 10 mM. PMID:24191757

Hu, Liang; Serpe, Michael J

2013-11-27

259

PhET Simulation: Reactions & Rates  

NSDL National Science Digital Library

This applet is designed for study of the kinetics of chemical reactions. It uses a model gas of three atomic species to illustrate the formation and disassociation of the different possible diatomic molecules. The user can run experiments with either one of each atom type or a gas of many atoms, controlling the density of the various species, the temperature, and energetics of the reaction. Data collection tools are available to calculate rate coefficients. Tips for teachers, ideas and activities are included. The direct link to the simulation is given as a mirror URL. This is part of a larger collection developed by the Physics Education Technology project (PhET).

2008-11-03

260

Ultimate detectability of volatile organic compounds: how much further can we reduce their ambient air sample volumes for analysis?  

PubMed

To understand the ultimately lowest detection range of volatile organic compounds (VOCs) in air, application of a high sensitivity analytical system was investigated by coupling thermal desorption (TD) technique with gas chromatography (GC) and time-of-flight (TOF) mass spectrometry (MS). The performance of the TD-GC/TOF MS system was evaluated using liquid standards of 19 target VOCs prepared in the range of 35 pg to 2.79 ng per ?L. Studies were carried out using both total ion chromatogram (TIC) and extracted ion chromatogram (EIC) mode. EIC mode was used for calibration to reduce background and to improve signal-to-noise. The detectability of 19 target VOCs, if assessed in terms of method detection limit (MDL, per US EPA definition) and limit of detection (LOD), averaged 5.90 pg and 0.122 pg, respectively, with the mean coefficient of correlation (R(2)) of 0.9975. The minimum quantifiable mass of target analytes, when determined using real air samples by the TD-GC/TOF MS, is highly comparable to the detection limits determined experimentally by standard. In fact, volumes for the actual detection of the major aromatic VOCs like benzene, toluene, and xylene (BTX) in ambient air samples were as low as 1.0 mL in the 0.11-2.25 ppb range. It was thus possible to demonstrate that most target compounds including those in low abundance could be reliably quantified at concentrations down to 0.1 ppb at sample volumes of less than 10 mL. The unique sensitivity of this advanced analytical system can ultimately lead to a shift in field sampling strategy with smaller air sample volumes facilitating faster, simpler air sampling (e.g., use of gas syringes rather than the relative complexity of pumps or bags/canisters), with greatly reduced risk of analyte breakthrough and minimal interference, e.g., from atmospheric humidity. The improved detection limits offered by this system can also enhance accuracy and measurement precision. PMID:22934885

Kim, Yong-Hyun; Kim, Ki-Hyun

2012-10-01

261

PhET Simulation: Balancing Chemical Equations  

NSDL National Science Digital Library

This simulation provides practice for beginners in balancing chemical equations. Introductory activities include separating a water molecule and making ammonia (a compound composed of sodium and hydrogen). The user clicks up or down arrows to add/delete atoms, while bar charts and balance scales are displayed to show when the equation is in balance. Next, apply what you've learned and play the "Balancing Game", with three levels of difficulty. Editor's Note: The game-like nature of this activity not only gives students practice with chemical equations, but goes much deeper. By viewing the distribution of individual atoms in real-time charts alongside the equation, the learner is building a basis to understand conservation of matter and chemical interactions. See Related Materials for a link to downloadable lessons and student guides developed specifically for use with this PhET simulation. This item is part of a larger collection of simulations developed by the Physics Education Technology project (PhET).

2011-08-15

262

The pH of Mars  

NASA Technical Reports Server (NTRS)

The Viking labeled release (LR) experiments provided data that can be used to determine the acid-base characteristics of the regolith. Constraints on the acid-base properties and redox potentials of the Martian surface material would provide additional information for determining what reactions are possible and defining formation conditions for the regolith. Calculations devised to determine the pH of Mars must include the amount of soluble acid species or base species present in the LR regolith sample and the solubility product of the carbonate with the limiting solubility. This analysis shows that CaCO3, either as calcite or aragonite, has the correct K(sub sp) to have produced the Viking LR successive injection reabsorption effects. Thus CaCO3 or another MeCO3 with very similar solubility characteristics must have been present on Mars. A small amount of soluble acid, but no more than 4 micro-mol per sample, could also have been present. It is concluded that the pH of the regolith is 7.2 +/- 0.1.

Plumb, R. C.; Bishop, J. L.; Edwards, J. O.

1993-01-01

263

NASA Graduate Student Researchers Program Ronald E. McNair PhD Program  

NASA Technical Reports Server (NTRS)

The NASA Ronald E. McNair PHD Program was funded in September 1995. Implementation began during the spring of 1996. The deferment of the actual program initial semester enabled the program to continue support through the fall semester of 1998. This was accomplished by a no-cost extension from August 15, 1998 through December 31, 1998. There were 12 fellows supported by the program in 1996, 15 fellows in 1997, and 15 fellows 1998. Current program capacity is 15 fellows per funding support. Support for the academic outreach component began in spring 1998. The program was named the "Good Enough" Crew Activity (GECA) in honor of Dr. McNair's philosophy of everyone being good enough to achieve anything they want bad enough. The program currently enrolls 65 students from the third through the eight grades. The program is held 12 Saturdays per semester. The time is 9:00 AM to 12:30 PM each Saturday Morning. Program direction and facilitation is jointly administered with the PHD fellows and the Saturday Academy staff. Dr. John Kelly, REM-PHD Principal Investigator serves in a program oversight and leadership capacity. Ms. Sunnie Howard, The NASA REM-PHD Administrative Coordinator serves in an administrative and logistical capacity. Mr. Aaron Hatch, the NASA-AMES Liaison Officer, serve@'in a consultative and curriculum review capacity. The first recognition activity will be held on December 12, 1998, with the students, parents, faculty, PHD fellows, and other local student support services persons. Program outreach efforts are jointly supported by the NASA REM-PHD Program and the National Space Grant College and Fellowship Program. The Ph.D. program reached its first milestone in May 1998. North Carolina A&T State University graduated the first Ph.D. fellows. The first three Ph.D. Alumni were Ronald E. McNair PHD Program Fellows. It is hoped that this is just the beginning of a highly acclaimed doctoral program. The ultimate program success will be recognized when the program begins to graduate 15 fellows per year. The Ph.D. Program is only three and a half years old and the expectations of graduating PH.D's in that timeframe, is a phenomenal accomplishment for any program in the country. Since inception of the NASA REM-PHD program, tuitions and fees have increased. Stipend support was increased to offer the Ph.D. program on a competitive basis. These increases will place allocation restraints on r_ the current level of funding. These issues are being addressed in the proposal and will bear their own merit.

Howard, Sunnie

1998-01-01

264

Development of FRP composite structural biomaterials: ultimate strength of the fiber/matrix interfacial bond in in vivo simulated environments.  

PubMed

Fiber reinforced polymer (FRP) composites are being developed as alternatives to metals for structural orthopedic implant applications. FRP composite fracture behavior and environmental interactions are distinctly different from those which occur in metals. These differences must be accounted for in the design and evaluation of implant performance. Fiber/matrix interfacial bond strength in a FRP composite is known to strongly influence fracture behavior. The interfacial bond strength of four candidate fiber/matrix combinations (carbon fiber/polycarbonate, carbon fiber/polysulfone, polyaramid fiber/polycarbonate, polyaramid fiber/polysulfone) were investigated at 37 degrees C in dry and in vivo simulated (saline, exudate) environments. Ultimate bond strength was measured by a single fiber-microdroplet pull-out test. Dry bond strengths were significantly decreased following exposure to either saline or exudate with bond strength loss being approximately equal in both the saline and exudate. Bond strength loss is attributed to the diffusion of water and/or salt ions into the sample and their interaction with interfacial bonding. Because bond degradation is dependent upon diffusion, diffusional equilibrium must be obtained in composite test samples before the full effect of the test environment upon composite mechanical behavior can be determined. PMID:1512281

Latour, R A; Black, J

1992-05-01

265

Assessing brain plasticity across the lifespan with transcranial magnetic stimulation: why, how, and what is the ultimate goal?  

PubMed

Sustaining brain and cognitive function across the lifespan must be one of the main biomedical goals of the twenty-first century. We need to aim to prevent neuropsychiatric diseases and, thus, to identify and remediate brain and cognitive dysfunction before clinical symptoms manifest and disability develops. The brain undergoes a complex array of changes from developmental years into old age, putatively the underpinnings of changes in cognition and behavior throughout life. A functionally "normal" brain is a changing brain, a brain whose capacity and mechanisms of change are shifting appropriately from one time-point to another in a given individual's life. Therefore, assessing the mechanisms of brain plasticity across the lifespan is critical to gain insight into an individual's brain health. Indexing brain plasticity in humans is possible with transcranial magnetic stimulation (TMS), which, in combination with neuroimaging, provides a powerful tool for exploring local cortical and brain network plasticity. Here, we review investigations to date, summarize findings, and discuss some of the challenges that need to be solved to enhance the use of TMS measures of brain plasticity across all ages. Ultimately, TMS measures of plasticity can become the foundation for a brain health index (BHI) to enable objective correlates of an individual's brain health over time, assessment across diseases and disorders, and reliable evaluation of indicators of efficacy of future preventive and therapeutic interventions. PMID:23565072

Freitas, Catarina; Farzan, Faranak; Pascual-Leone, Alvaro

2013-01-01

266

Assessing brain plasticity across the lifespan with transcranial magnetic stimulation: why, how, and what is the ultimate goal?  

PubMed Central

Sustaining brain and cognitive function across the lifespan must be one of the main biomedical goals of the twenty-first century. We need to aim to prevent neuropsychiatric diseases and, thus, to identify and remediate brain and cognitive dysfunction before clinical symptoms manifest and disability develops. The brain undergoes a complex array of changes from developmental years into old age, putatively the underpinnings of changes in cognition and behavior throughout life. A functionally “normal” brain is a changing brain, a brain whose capacity and mechanisms of change are shifting appropriately from one time-point to another in a given individual's life. Therefore, assessing the mechanisms of brain plasticity across the lifespan is critical to gain insight into an individual's brain health. Indexing brain plasticity in humans is possible with transcranial magnetic stimulation (TMS), which, in combination with neuroimaging, provides a powerful tool for exploring local cortical and brain network plasticity. Here, we review investigations to date, summarize findings, and discuss some of the challenges that need to be solved to enhance the use of TMS measures of brain plasticity across all ages. Ultimately, TMS measures of plasticity can become the foundation for a brain health index (BHI) to enable objective correlates of an individual's brain health over time, assessment across diseases and disorders, and reliable evaluation of indicators of efficacy of future preventive and therapeutic interventions.

Freitas, Catarina; Farzan, Faranak; Pascual-Leone, Alvaro

2013-01-01

267

Effects of shear stirrup details on ultimate capacity and tensile-membrane behavior of reinforced concrete slabs. Final report  

SciTech Connect

At the time this study was initiated, civil defense planning in the United States called for the evacuation of nonessential personnel to safe host areas when a nuclear attack is probable, requiring the construction of blasts shelters to protect the keyworkers remaining in the risk areas. The placement of shear stirrups in the one-way reinforced concrete roof slabs of the shelters will contribute significantly to project costs. Ten one-way reinforced concrete slabs were statically and uniformly loaded with water pressure, primarily to investigate the effect of stirrups and stirrup details on the load-response behavior of the slabs. The slabs had clear spans of 24.0 inches, span to effective depth ratios of 12.4, tensile reinforcement of 0.75%, and concrete strengths of approximately 5,000 psi. The test series significantly increased the data base for uniformly loaded one-way slabs. Support rotations between 13.1 and 20.6 degrees were observed. A more ductile behavior was observed in slabs with construction details, implying better concrete confinement due to more confining steel (i.e., closely spaced stirrups, double-leg stirrups, and closely spaced principal reinforcing bars). The parameters investigated did not appear to have a significant effect on ultimate load capacity.

Woodson, S.C.

1985-08-01

268

CRCHD - CRCHD Research - Principal Investigator: Bruce Macher, Ph.D.  

Cancer.gov

CRCHD - CRCHD Research - Principal Investigator: Bruce Macher, Ph.D. Home Disparities Research Programs CRCHD Ongoing Research PACHE PACHE Partnership Listing Bruce Macher, Ph.D. CRCHD Research Ongoing Research

269

CRCHD - CRCHD Research - Principal Investigator: Bruce Macher, Ph.D.  

Cancer.gov

CRCHD - CRCHD Research - Principal Investigator: Bruce Macher, Ph.D. Home Health Disparities Research CRCHD Research Ongoing Research PACHE PACHE Partnership Listing Bruce Macher, Ph.D. CRCHD Research Ongoing

270

Catalytic Decomposition of PH3 on Heated Tungsten Wire Surfaces  

NASA Astrophysics Data System (ADS)

The catalytic decomposition processes of PH3 on heated tungsten surfaces were studied to clarify the mechanisms governing phosphorus doping into silicon substrates. Mass spectrometric measurements show that PH3 can be decomposed by more than 50% over 2000 K. H, P, PH, and PH2 radicals were identified by laser spectroscopic techniques. Absolute density measurements of these radical species, as well as their PH3 flow rate dependence, show that the major products on the catalyst surfaces are P and H atoms, while PH and PH2 are produced in secondary processes in the gas phase. In other words, catalytic decomposition, unlike plasma decomposition processes, can be a clean source of P atoms, which can be the only major dopant precursors. In the presence of an excess amount of H2, the apparent decomposition efficiency is small. This can be explained by rapid cyclic reactions including decomposition, deposition, and etching to reproduce PH3.

Umemoto, Hironobu; Nishihara, Yushin; Ishikawa, Takuma; Yamamoto, Shingo

2012-08-01

271

Putting the pH into phosphatidic acid signaling  

PubMed Central

The lipid phosphatidic acid (PA) has important roles in cell signaling and metabolic regulation in all organisms. New evidence indicates that PA also has an unprecedented role as a pH biosensor, coupling changes in pH to intracellular signaling pathways. pH sensing is a property of the phosphomonoester headgroup of PA. A number of other potent signaling lipids also contain headgroups with phosphomonoesters, implying that pH sensing by lipids may be widespread in biology.

2011-01-01

272

Use and abuse of pH measurements  

Microsoft Academic Search

The development of the concept of pH from its invention by Sorenson in 1909 to the present-day National Bureau of Standards' pH scale is reviewed. The liquid junction potential problem involved in the use of the pH meter is discussed in detail. The magnitude of the error due to the junction potential depends upon the pH, ionic strength, nature of

Isaac Feldman

1956-01-01

273

New Routes to the PhD: Cause for Concern?  

ERIC Educational Resources Information Center

Recent developments suggest that the PhD is at a turning point. Professional groups have criticised the so-called traditional PhD. New routes to the PhD are proposed by several bodies and endorsed by one funding council. In light of these developments, it is appropriate to ask what the implications are for the PhD and for the academy. A focus…

Johnston, Bill; Murray, Rowena

2004-01-01

274

Organelle pH in the Arabidopsis endomembrane system.  

PubMed

The pH of intracellular compartments is essential for the viability of cells. Despite its relevance, little is known about the pH of these compartments. To measure pH in vivo, we have first generated two pH sensors by combining the improved-solubility feature of solubility-modified green fluorescent protein (GFP) (smGFP) with the pH-sensing capability of the pHluorins and codon optimized for expression in Arabidopsis. PEpHluorin (plant-solubility-modified ecliptic pHluorin) gradually loses fluorescence as pH is lowered with fluorescence vanishing at pH 6.2 and PRpHluorin (plant-solubility-modified ratiomatric pHluorin), a dual-excitation sensor, allowing for precise measurements. Compartment-specific sensors were generated by further fusing specific sorting signals to PEpHluorin and PRpHluorin. Our results show that the pH of cytosol and nucleus is similar (pH 7.3 and 7.2), while peroxisomes, mitochondrial matrix, and plastidial stroma have alkaline pH. Compartments of the secretory pathway reveal a gradual acidification, spanning from pH 7.1 in the endoplasmic reticulum (ER) to pH 5.2 in the vacuole. Surprisingly, pH in the trans-Golgi network (TGN) and multivesicular body (MVB) is, with pH 6.3 and 6.2, quite similar. The inhibition of vacuolar-type H(+)-ATPase (V-ATPase) with concanamycin A (ConcA) caused drastic increase in pH in TGN and vacuole. Overall, the PEpHluorin and PRpHluorin are excellent pH sensors for visualization and quantification of pH in vivo, respectively. PMID:23702593

Shen, Jinbo; Zeng, Yonglun; Zhuang, Xiaohong; Sun, Lei; Yao, Xiaoqiang; Pimpl, Peter; Jiang, Liwen

2013-09-01

275

Application of SERS Nanoparticles for Intracellular pH Measurements.  

National Technical Information Service (NTIS)

We present an alternative approach to optical probes that will ultimately allow us to measure chemical concentrations in microenvironments within cells and tissues. This approach is based on monitoring the surface-enhanced Raman scattering (SERS) response...

T. Laurence C. Talley M. Colvin T. Huser

2004-01-01

276

Notes on the Measurement of pH Values.  

National Technical Information Service (NTIS)

The original definition of pH is: pH = -log a(sub H). Where a(sub H) is the (relative) hydrogen ion activity. However, a single ion activity cannot be measured. Activities of individual ionic species are necessarily conventional. The pH number, of course,...

R. M. Carranza R. B. Rebak

2005-01-01

277

A Multiattributes Approach for Ranking PhD Programs  

ERIC Educational Resources Information Center

In its plan to combat the PhD shortage crisis, the Association to Advance Collegiate Schools of Business International (AACSB; 2003) has called for the development of PhD program rankings to serve as incentives for academic institutions to invest more in PhD programs, thereby counterbalancing the disproportionate influence of master of business…

Urbancic, Frank R.

2008-01-01

278

pH dynamics in sewers and its modeling.  

PubMed

pH variation in sewers has a significant effect on hydrogen sulfide production and emissions, and hence its accurate prediction is critical for the optimization of mitigation strategies. In this study, the nature and dynamics of pH variation in a sewer system is examined. Three sewer systems collecting domestic wastewater were monitored, with pH in all cases showing large diurnal variations. pH in fresh sewage in all three cases had a very similar trend with maximum pH in the range of 8.5-8.7. pH variation in fresh sewage followed the same pattern as the sewage flow rate, suggesting that sewage pH is influenced by household water use. Nitrogen content of the wastewater was found to be the most influential factor causing pH variation in fresh sewage, with the total ammonium concentration variation well correlated with the pH variation. A methodology for predicting pH variation in sewers is developed and calibration protocols proposed. The methodology, which is based on the concept of charge balance, was validated using titration curves and field pH data. Measurement of the total ammonium concentration in fresh sewage was found necessary and adequate for the calibration of the charge balance-based pH model. PMID:23962970

Sharma, Keshab; Ganigue, Ramon; Yuan, Zhiguo

2013-10-15

279

Writing your own activities - PhET Activity Guidelines  

NSDL National Science Digital Library

You can create your own lectures, homework, and labs around any PhET simulation by using the PhET Activity Guidelines . These guidelines will help you create "guided inquiry activities which encourage students to construct their own understanding," which are the most effective way to use PhET simulations.

Mckagan, Sam

280

Recent bruising in cattle at abattoirs.  

PubMed

In two surveys of a total of over 16,000 cattle carcases, animals from live auctions had more bruising and more meat rejected for bruising than animals from dealers and farms. The proportion of carcases with stick-markings was higher in market cattle (2.5 per cent) than in cattle from farms (0.9 per cent). The amount of bruising was much higher in animals which were stick-marked (35 per cent) than in the whole population surveyed (6.5 per cent). Young bulls had the lowest percentage of bruising and the least amount of meat rejected of all the categories of animals surveyed. There was less "important' bruising in animals travelling less than 50 miles from markets, but over 50 miles the amount of "important' bruising did not increase. However, the incidence of all bruising increased with the distance travelled and with the time the animal spent in the lairage. More than half the carcases surveyed (59 per cent) had some degree of bruising caused by preslaughter handling. The areas most frequently bruised were the butt and hip, loin, shoulder/foreleg and neck, hind leg and flank/brisket. The number of carcases with an ultimate pH (pHu) of over 5-8 and the average pHu of the muscle increased with the amount of carcase bruising. PMID:8650914

McNally, P W; Warriss, P D

1996-02-10

281

Bruising in Slaughter Cattle and Its Relationship with Creatine Kinase Levels and Beef Quality as Affected by Animal Related Factors  

PubMed Central

The objective of the study was to determine the effects of animal related factors on bruising in slaughter cattle, creatine kinase (CK) and beef quality. Three hundred and twenty one cattle from three breeds (108 Bonsmara, 130 Beefmaster and 83 Brahman) were used in this study. The animals were grouped as follows: Group 1 (16 months old), Group 2 (18 months old) and Group 3 (24 months old). At exsanguinations, blood samples for CK determination were collected using disposable vacutainer tubes. Muscularis longissimus thoracis et lumborum (LTL) was collected 24 h after slaughter to determine the colour (L*, a*, and b*) and ultimate pH (pHu) of beef. Breed, sex and age had significant effects (p<0.05) on bruising score, CK levels and beef quality. Bonsmara breed had the highest (80%) bruising score percentage, CK (705.3±80.57 U/L) and pHu (6.3±0.05) values while the Bonsmara had the highest L* (24.8±0.78) a* (17.5±0.53) and b* (12.8±0.53) values. Higher CK levels were also observed in winter compared to summer, spring and autumn respectively. Therefore, animal factors (sex, breed and animal age at slaughter) contribute to the development of bruises and have an effect on the levels of CK and meat quality. It was also concluded that there is no significant relationship between meat parameters (L,* a*, and b*) and CK levels.

Mpakama, T.; Chulayo, A. Y.; Muchenje, V.

2014-01-01

282

PhET Simulation: Build a Molecule  

NSDL National Science Digital Library

Students will have fun constructing simple molecules with this simulation, while also gaining insight about how to read molecular formulas. Click and drag atoms to see which ones bond to form diatomic molecules (composed of a pair of the same element.) Drag different atoms into the field to build a more complex molecule composed of different elements. After a molecule is built, it can be viewed in 3D models. Editor's Note: This resource is appropriate for grades 6-12, with teacher adaptation. Basic concepts of molecular structure should be comprehensible in the middle grades. Students will recognize that the subscript in the molecular formula indicates the number of that atom in the molecule, and the coefficient indicates the total number of molecules. High school teachers may wish to introduce covalent bonding and electron sharing. This item is part of a larger collection of simulations developed by the Physics Education Technology project (PhET).

2011-06-27

283

Ian Douglass Coulter, PhD  

PubMed Central

This paper focuses on Dr. Ian Coulter’s accomplishments from the time he became Executive Vice-President of CMCC in 1981, until he ended his presidency with a year’s administrative leave in 1990. Annual planning initiatives, pedagogy, scholarship, conflicts, and the quest for university affiliation are discussed as well as his legacy to the College and the chiropractic profession. The term “adventurous” was first attributed to Coulter by Oswald Hall, PhD, Professor Emeritus, University of Toronto who had worked closely with Coulter in a major investigation of the chiropractic profession from 1976 to 1979. Throughout this article the author tries to capture the spirit of daring, innovation and intellect that permeated Coulter’s presidency, enthralling his advocates and confounding his detractors.

Brown, Douglas M

2004-01-01

284

In Memoriam; Recent Ph.D.; Honors  

NASA Astrophysics Data System (ADS)

Byron Boville, 51, 6 June 2006; Atmospheric Sciences, 1991 David Cummings, 87, 5 September 2006; retired member, Tectonophysics, 1963 Andrew Godfrey, 66, 18 August 2006; Hydrology, 1995 Henry M. Morris, 87, 26 February 2006; Hydrology, 1948 Fred N. Spiess, 86, 8 September 2006; Life Fellow, Marine Geology and Geophysics, 1957 Recent Ph.D. Jeremy Shannon, Geology, Michigan Technological University, April 2006. ``Development and application of new techniques for sulfur dioxide monitoring at active volcanoes.'' Advisor: Gregg Bluth. Honors Mark D. Zoback of Stanford University received the Emil Wiechert Medal in March 2006 from the German Geophysical Society. Zoback was honored for his original and essential scientific contributions to the investigation of the distribution of tectonic stresses on the globe and at depth, which are fundamental for the understanding of the tectonic processes in the lithosphere.

2006-10-01

285

PhET Simulation: Magnets and Electromagnets  

NSDL National Science Digital Library

In this interactive simulation, users explore the interactions between a compass and a bar magnet and investigate characteristics of electromagnets. This resource was developed to help students build a foundation to understand electromagnetism and factors affecting magnetic field strength. It is appropriate for use in middle school and high school, and could also be adapted for use in college physics preparatory courses. This resource is part of the PhET project (Physics Education Technology) a growing collection of simulations and curriculum support for teachers and learners of physics, biology, chemistry, and earth science. See Related Items for a link to a standards-based lesson plan and elicitation questions developed specifically to accompany the "Magnets and Electromagnets" simulation.

2010-12-02

286

Elementary PhUn Fair - PhUn Week Poster Session EB 2012  

NSDL National Science Digital Library

Approximately 40 high school students, enrolled in the Clinton High School Human Anatomy & Physiology course, organized and hosted a community PhUn Fair. During a week early in the semester, students researched various human physiological systems. The following week, students developed and planned learning stations based on their research. Students received input and feedback from a visiting physiologist, their instructor, and their peers. The culminating event was the PhUn Fair, during which more than 100 second-graders spent an afternoon rotating through eight active learning stations taught by the high school students. All learning stations introduced a different physiological concept through inquiry-based activities. The PhUn Fair concluded with a question and answer period with the visiting physiologist. While the high school students conducted the research and planning during the two weeks prior to the PhUn Fair, initial organization was conducted by the authors during the APS Frontiers in Physiology Fellowship summer research experience. P. Schork was supported by 2011 The American Physiological Society Frontiers in Physiology Fellowship.

Pauline Schork (Clinton High School)

2012-04-22

287

Plastic pH electrodes for the measurement of gastrointestinal pH.  

PubMed Central

Plastic electrodes have been developed for measuring pH in the human gastrointestinal tract. The electrodes have a plastic hydrogen ion sensitive membrane sealed to a length of fluid filled PVC tubing. Two recently developed hydrogen ion sensitive ligands have been examined. Their operational characteristics have been described. These electrodes have an electrical response of 52 to 58 mV/pH unit change in the range pH 4-9, with a diminished response outwith this range. They have a low resistance value and a fast response time of one second to reach 90% of their maximum response. The electrodes can be passed down the biopsy channel of an endoscope to obtain mucosal pH readings under direct vision. Readings obtained in this way using plastic electrodes are comparable to those obtained with glass electrodes. Alternatively, these electrodes can be joined to a Crosby capsule, allowing continuous recording of mucosal pH through to the jejunum during jejunal biopsy procedures. These electrodes can be used repeatedly or may be acceptable as inexpensive disposable items for sterile clinical use. Images Fig. 1

Rawlings, J M; Lucas, M L

1985-01-01

288

Comparison of Rumen Fluid pH by Continuous Telemetry System and Bench pH Meter in Sheep with Different Ranges of Ruminal pH  

PubMed Central

We aimed to compare the measurements of sheep ruminal pH using a continuous telemetry system or a bench pH meter using sheep with different degrees of ruminal pH. Ruminal lactic acidosis was induced in nine adult crossbred Santa Ines sheep by the administration of 15?g of sucrose per kg/BW. Samples of rumen fluid were collected at the baseline, before the induction of acidosis (T0) and at six, 12, 18, 24, 48, and 72 hours after the induction for pH measurement using a bench pH meter. During this 72-hour period, all animals had electrodes for the continuous measurement of pH. The results were compared using the Bland-Altman analysis of agreement, Pearson coefficients of correlation and determination, and paired analysis of variance with Student's t-test. The measurement methods presented a strong correlation (r = 0.94, P < 0.05) but the rumen pH that was measured continuously using a telemetry system resulted in lower values than the bench pH meter (overall mean of 5.38 and 5.48, resp., P = 0.0001). The telemetry system was able to detect smaller changes in rumen fluid pH and was more accurate in diagnosing both subacute ruminal lactic acidosis and acute ruminal lactic acidosis in sheep.

Reis, Leonardo F.; Minervino, Antonio H. H.; Araujo, Carolina A. S. C.; Sousa, Rejane S.; Oliveira, Francisco L. C.; Rodrigues, Frederico A. M. L.; Meira-Junior, Enoch B. S.; Barreto-Junior, Raimundo A.; Mori, Clara S.; Ortolani, Enrico L.

2014-01-01

289

PhD Students' Work Conditions and Study Environment in University- and Industry-Based PhD Programmes  

ERIC Educational Resources Information Center

During the last 10 years, new models of funding and training PhD students have been established in Denmark in order to integrate industry into the entire PhD education. Several programmes have been conducted where it is possible to co-finance PhD scholarships or to become an employee as an industrial PhD in a company. An important question is what…

Kolmos, A.; Kofoed, L. B.; Du, X. Y.

2008-01-01

290

On the ?? to ? transformation in maraging (grade 350), PH 13-8 Mo and 17-4 PH steels  

Microsoft Academic Search

The martensite to austenite transformation during continuous heating was studied over a range of heating rates for 350 grade maraging steel (M350), PH 13-8 Mo, and 17-4 PH stainless steel using a programmable dilatometer. The ???? transformation splits into two steps at lower heating rates for the M350 and PH 13-8 Mo, whereas occurs in one step for 17-4 PH.

Rajeev Kapoor; I. S. Batra

2004-01-01

291

The FP7 ULTimateCO2 project: a study of the long term fate of CO2  

NASA Astrophysics Data System (ADS)

The objectives of the European FP7 ULTimateCO2 project are to study specific processes that could influence the long-term fate of geologically stored CO2, mainly: the trapping mechanisms occurring in the storage reservoir, the influence of fluid-rock interactions on mechanical integrity of caprock and well vicinity, and also the modifications induced at the regional scale (brine displacement, fault reactivation, hydrogeology changes...). A comprehensive approach combining laboratory experiments, numerical modeling and natural analogue studies is developed to assess all the processes mentioned above. A collection of data has been generated from natural and industrial (oil industry) analogues on the fluid flow and mechanical properties, structure, and mineralogy of faults and fractures that could affect the long-term storage capacity of underground CO2 storage sites. To address geochemical trapping at reservoir scale, an experimental approach is developed using sandstone core materials in batch reactive mode with CO2 and impurities at reservoir pressure and temperature conditions. Three inter-related lines of laboratory experiments investigate the long-term evolution of the mechanical properties and sealing integrity of fractured and faulted caprocks using Opalinus clay of Mont Terri Gallery (Switzerland), an analogue for caprock well investigated in the past for nuclear waste disposal purpose. To evaluate the interactions between CO2 (and formation fluid) and the well environment (formation, cement, casing) and to assess the consequences of these interactions on the transport properties of well materials, a 1 to 1 scale experiment has been set in the Mont Terri Gallery Opalinus clay to reproduce classical well objects (cemented annulus, casing and cement plug) perforating caprock formations. An extensive program of numerical modeling is also developed to calibrate, to reproduce and to extrapolate the experimental results at longer time scales including uncertainty assessment methods. www.ultimateco2.eu

Audigane, Pascal; Waldmann, Svenja; Pearce, Jonathan; Dimier, Alain; Le Gallo, Yann; Frykman, Peter; Maurand, Nicolas; Gherardi, Fabrizio; Yalamas, Thierry; Cremer, Holger; Spiers, Chris; Nussbaum, Christophe

2014-05-01

292

Pre-heated dual-cured resin cements: analysis of the degree of conversion and ultimate tensile strength.  

PubMed

This study evaluated the degree of conversion (DC) and ultimate tensile strength (UTS) of dual-cured resin cements heated to 50º C prior to and during polymerization. Disc- and hourglass-shaped specimens of Rely X ARC (RX) and Variolink II (VII) were obtained using addition silicon molds. The products were manipulated at 25º C or 50º C and were subjected to 3 curing conditions: light-activation through a glass slide or through a pre-cured 2-mm thick resin composite disc, or they were allowed to self-cure (SC). All specimens were dark-stored dry for 15 days. For DC analysis, the resin cements were placed into the mold located on the center of a horizontal diamond on the attenuated total reflectance element in the optical bench of a Fourier Transformed Infrared spectrometer. Infrared spectra (n = 6) were collected between 1680 and 1500 cm-1, and DC was calculated by standard methods using changes in ratios of aliphatic-to-aromatic C=C absorption peaks from uncured and cured states. For UTS test, specimens (n = 10) were tested in tension in a universal testing machine (crosshead speed of 1 mm/min) until failure. DC and UTS data were submitted to 2-way ANOVA, followed by Tukey's test (?= 5%). Both products showed higher DC at 50º C than at 25º C in all curing conditions. No significant difference in UTS was noted between most light-activated groups at 25º C and those at 50º C. VII SC groups showed higher UTS at 50º C than at 25º C (p < 0.05). Increased temperature led to higher DC, but its effects on resin cement UTS depended on the curing condition. PMID:21537644

França, Flávio Álvares; Oliveira, Michele de; Rodrigues, José Augusto; Arrais, César Augusto Galvão

2011-01-01

293

Phosphate availability and the ultimate control of new nitrogen input by nitrogen fixation in the tropical Pacific Ocean  

NASA Astrophysics Data System (ADS)

Due to the low atmospheric input of phosphate into the open ocean, it is one of the key nutrients that could ultimately control primary production and carbon export into the deep ocean. The observed trend over the last 20 years has shown a decrease in the dissolved inorganic phosphate (DIP) pool in the North Pacific gyre, which has been correlated to the increase in di-nitrogen (N2) fixation rates. Following a NW-SE transect, in the Southeast Pacific during the early austral summer (BIOSOPE cruise), we present data on DIP, dissolved organic phosphate (DOP) and particulate phosphate (PP) pools along with DIP turnover times (TDIP) and N2 fixation rates. We observed a decrease in DIP concentration from the edges to the centre of the gyre. Nevertheless the DIP concentrations remained above 100 nmol L-1 and T DIP was more than 6 months in the centre of the gyre; DIP availability remained largely above the level required for phosphate limitation to occur and the absence of Trichodesmium spp and low nitrogen fixation rates were likely to be controlled by other factors such as temperature or iron availability. This contrasts with recent observations in the North Pacific Ocean at the ALOHA station and in the western Pacific Ocean at the same latitude (DIAPALIS cruises) where lower DIP concentrations (<20 nmol L-1) and T DIP <50 h were measured during the summer season in the upper layer. The South Pacific gyre can be considered a High Phosphate Low Chlorophyll (HPLC) oligotrophic area, which could potentially support high N2 fixation rates and possibly carbon dioxide sequestration, if the primary ecophysiological controls, temperature and/or iron availability, were alleviated.

Moutin, T.; Karl, D. M.; Duhamel, S.; Rimmelin, P.; Raimbault, P.; van Mooy, B. A. S.; Claustre, H.

2008-01-01

294

Time course of pH change in plant epidermis using microscopic pH imaging system  

NASA Astrophysics Data System (ADS)

We established a microscopic pH imaging system to track the time course of pH change in plant epidermis in vivo. In the previous research, we have found out that anthocyanin containing cells have higher pH. However, it was not clear whether the anthocyanin increased the pH or anthocyanin was synthesized result from the higher pH. Therefore, we further investigated the relationship between anthocyanin and pH change. To track the time course of pH change in plant epidermis, we established a system using luminescent imaging technique. We used HPTS (8-Hydroxypyrene-1,3,6-Trisulfonate) as pH indicator and applied excitation ratio imaging method. Luminescent image was converted to a pH distribution by obtained in vitro calibration using known pH solution. Cellular level observation was enabled by merging microscopic color picture of the same region to the pH change image. The established system was applied to epidermal cells of red-tip leaf lettuce, Lactuca Sativa L. and the time course was tracked in the growth process. We would discuss about the relationship between anthocyanin and pH change in plant epidermis.

Dan, Risako; Shimizu, Megumi; Kazama, Haruko; Sakaue, Hirotaka

2010-11-01

295

Imaging of Mitochondrial pH Using SNARF-1  

PubMed Central

Laser scanning confocal microscopy provides the ability to image submicron sections in living cells and tissues. In conjunction with pH-indicating fluorescent probes, confocal microscopy can be used to visualize the distribution of pH inside living cells. Here, we describe a confocal microscopic technique to image intracellular pH in living cells using SNARF-1, a ratiometric pH-indicating fluorescent probe. SNARF-1 is ester-loaded into the cytosol and mitochondria of adult cardiac myocytes. Using 568-nm excitation, emitted fluorescence longer and shorter than 595-nm are imaged and then ratioed after background subtraction. Ratio values for each pixel are converted to values of pH using a standard curve (lookup table). Images of the intracellular distribution of pH show cytosolic and nuclear areas to have a pH of ~7.1, but in regions corresponding to mitochondria, pH is 8.0, giving a mitochondrial ?pH of 0.9. During hypoxia, mitochondrial pH decreases to cytosolic values, signifying the collapse of ?pH. These results illustrate the ability of laser scanning confocal microscopy to image the intracellular distribution of pH in living cells and to determine mitochondrial ?pH.

Ramshesh, Venkat K.; Lemasters, John J.

2014-01-01

296

Variation in hydraulic conductivity with decreasing pH in a biologically-clogged porous medium (Invited)  

NASA Astrophysics Data System (ADS)

Microbial biomass can clog porous media and ultimately affect both structural and mineral trapping of CO2 in geological carbon storage reservoirs. Whether biomass can remain intact following a sudden decrease in groundwater pH, a geochemical change associated with CO2 injection, is unclear. We examined this question using twelve biologically-active and three control column-reactor experiments. Cell abundance and distribution was monitored using confocal microscopy, plating, and direct counting. Hydraulic conductivity (K) was monitored using pressure sensors. Growth occurred for four days at neutral pH. During that time, K within the clogged portion of the reactors decreased from 0.013 to 0.0006 cm s-1 on average, a 1.47 log reduction. Next, the pH of the inflowing aqueous medium was lowered to pH 4 in six experiments and pH 5.7 in six experiments. As a result, K increased in five of the pH 4 experiments and two of the pH 5.7 experiments. Despite this increase, however, the columns remained largely clogged. Compared to pre-inoculation K values, log reductions averaged 1.13 and 1.44 in pH 4 and pH 5.7 experiments, respectively. Our findings show that biomass can largely remain intact following acidification and continue to reduce K, even when considerable cell stress and death occurs. This material is based upon work supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001114. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Altman, S. J.; Kirk, M. F.; Santillan, E. U.; McGrath, L. K.

2013-12-01

297

Effects of conventional welding and laser welding on the tensile strength, ultimate tensile strength and surface characteristics of two cobalt-chromium alloys: a comparative study.  

PubMed

The purpose of this study was to evaluate the efficacy of laser welding and conventional welding on the tensile strength and ultimate tensile strength of the cobalt-chromium alloy. Samples were prepared with two commercially available cobalt-chromium alloys (Wironium plus and Diadur alloy). The samples were sectioned and the broken fragments were joined using Conventional and Laser welding techniques. The welded joints were subjected to tensile and ultimate tensile strength testing; and scanning electron microscope to evaluate the surface characteristics at the welded site. Both on laser welding as well as on conventional welding technique, Diadur alloy samples showed lesser values when tested for tensile and ultimate tensile strength when compared to Wironium alloy samples. Under the scanning electron microscope, the laser welded joints show uniform welding and continuous molt pool all over the surface with less porosity than the conventionally welded joints. Laser welding is an advantageous method of connecting or repairing cast metal prosthetic frameworks. PMID:23858281

Madhan Kumar, Seenivasan; Sethumadhava, Jayesh Raghavendra; Anand Kumar, Vaidyanathan; Manita, Grover

2012-06-01

298

Bridging the Reef gaps: first evidence for corals surviving under low pH conditions  

NASA Astrophysics Data System (ADS)

Following two major extinction events, the late Permian and Triassic/Jurassic, there is a long absence of corals from the geological record followed by a recurrence coral fossils. This unusual disappearance and reappearance, referred to commonly as 'reef gaps', was explained as a failure in sampling effort, and/or the movement of these species into geographic 'refugia' that have not been found. Because the phylogeny of recent corals suggests their origin in the pre-Permian-extinction , an alternative explanation for reef gaps hypothesized that corals have a means of alternating between soft bodies and fossilizing forms. This study supports this hypothesis. Thirty coral fragments from 5 coral colonies of the scleractinian Mediterranean corals Oculina patagonica (encrusting) and Madracis pharencis (bulbous) were subjected to pH 7.4-7.6 (in accordance with the pH projected by the IPCC for the year 2300) and 30 fragments to pH 8.0-8.3 (ambient) over a period of 12 months. 100% of the colonies in the experiment and 90% of all polyps survived to the end the experiment. The corals grown in acidified conditions, where skeleton-building conditions were absent, maintained basic life functions as a solitary skeleton-less ecophenotype resembling a sea anemone. On an evolutionary scale, these results provide a possible explanation to coral survival over major extinction events such as the Permian/Triassic and Triassic/Jurassic events. It is important to note that these results only demonstrate that corals can persist as soft bodied ecophoenotypes, but the loss of reef framework has major ramifications to the entire structure and function of coral reef ecosystems, ultimately impacting the services they provide to human society.

Tchernov, D.; Fine, M.

2007-12-01

299

Microtubule assembly and disassembly at alkaline pH  

PubMed Central

Although it is now apparent that the intracellular pH may rise considerably above neutrality under physiological conditions, information on the effect of alkaline pH on microtubule assembly and disassembly is still quite fragmentay. We have studied the assembly/disassembly of bovine brain microtubule protein at alkaline pH in vitro. When microtubules are assembled to a new steady state at pH less than 7 and pH is then made more alkaline, they undergo a rapid disassembly to a new steady state. This disassembly is reversed by acidification. The degree of disassembly is determined largely by the pH- dependence of the critical concentration, which increases five to eight times, from pH 7 to 8. A fraction of assembly-incompetent tubulin is identified that increases with pH, but its incompetency is largely reversed with acidification. Measurements of microtubule lengths are used to indicate that disassembly occurs by uniform shortening of microtubules. A comparison of shortening by alkalinization with dilution suggests that the intrinsic rate of disassembly is accelerated by increasing pH. The capacity for initiating assembly is progressively lost with incubation at alkaline pH (although some protection is afforded by sulfhydryl-reducing agents). However, direct assembly from depolymerized mixtures is possible at least up to pH 8.3, and the steady state achieved at these alkaline pH values is stable. Such preparations are readily disassembled by cold and podophyllotoxin (PLN). Disassembly induced by PLN is also markedly enhanced at alkaline pH, suggesting a corresponding enhancement of “treadmilling.” The implications of physiological events leading to alkaline shifts of pH for microtubule assembly/disassembly are discussed, particularly in the light of recent hypotheses regarding treadmilling and its role in controlling the distribution of microtubules in vivo.

Regula, CS; Pfeiffer; Berlin, RD

1981-01-01

300

The CH3PH 2 and CH 3PH isomers: isomerization, hydrogen release, thermodynamic, and spectroscopy properties.  

PubMed

In this study was performed a quantum chemical investigation of the methylphosphine molecule and its radical, which may show potential implications in interstellar processes, and may be crucial atmospheric tracer gasses in the atmosphere of Giant planets. The analyses were performed with the density functional theory and coupled cluster methods. The anharmonic vibrational modes were predicted for all the isomers. The atomic charge distribution was analyzed with different methodologies and some methods fail to establish the correct sign for phosphorous atom charges. The CH2PH2/CH3PH and CHPH3/CH3PH energy gap is 16.45-17.43 and 67.05-69.02 kcal mol(-1), respectively. The CH2PH3/CH3PH2 energy difference ranges from 44.62 to 50.05 kcal mol(-1). The ionization energy predicted with the W1BD method for CH3PH and CH3PH2 are 8.73 and 9.01 eV, respectively. The heat of formation at 298 K for each molecule were calculated in kcal mol(-1): CH3PH (24.16-25.27), CH2PH2 (41.20-42.47), CHPH3 (92.50-94.23), CH3PH2 (-4.73-2.83) and CH2PH3 (40.03-42.55). The rotational energy barriers for CH3PH2 and CH2PH3 are 1.65 and 2.81 kcal mol(-1), respectively. The CHPH3???CH2PH2 unimolecular arrangement presents a barrier energy of 29.89 kcal mol(-1), whereas CH3PH???CH2PH2 is accessible overcoming a barrier of 42.42 kcal mol(-1). The H2-release routes for CH2PH2 from carbon and phosphorous atoms show a barrier of 98.19 and 46.67 kcal mol(-1), respectively. For the CH3PH2???CH2PH3 isomerization, an energy barrier of 94.00 kcal mol(-1) was predicted, while for the H2-release pathway for CH3PH2 it is necessary to pass a potential energy barrier of 97.56 kcal mol(-1). PMID:25037491

Viana, Rommel B; da Silva, Albérico B F

2014-08-01

301

To PhET or Not To PhET: That Is the Question  

NASA Astrophysics Data System (ADS)

The investigation examined use of a Physics Education Technology (PhET) simulation versus a hands-on lab activity on student's conceptual understanding of physics content. Topics of study included vectors, projectile motion, direct current (DC) circuits, and the photoelectric effect. Participants consisted of high school juniors and seniors enrolled in a physics course. Assessment instruments consisted of questions taken from the Vector Evaluation Test, the Electric Circuits Concept Evaluation test, textbook test banks, or written to address concepts under evaluation. Data collection consisted of a pre-test score, a post-test score, and a gain score. The conceptual understanding of the experimental and the control groups did not significantly differ for vectors and DC circuits. The conceptual understanding of the experimental and control groups did significantly differ for projectile motion. The results indicated a conceptual gain for students using the photoelectric effect simulation. Student attitudes towards the PhET simulations were positive.

Casao, Robert

2008-10-01

302

Occurrence of the antidiabetic drug Metformin and its ultimate transformation product Guanylurea in several compartments of the aquatic cycle.  

PubMed

In 2030, the World Health Organization estimates that more than 350million people will be diagnosed with diabetes. Consequently, Metformin - the biguanide drug of choice orally administered for diabetes type II - is anticipated to see a spike in production. Unlike many pharmaceutical drugs, Metformin (Met) is not metabolized by humans but passes through the body unchanged. Entering aquatic compartments, such as in sewage, it can be bacterially transformed to the ultimate transformation product Guanylurea (Gua). Sampling over one week (n=5) from a Southern German sewage treatment plant revealed very high average (AV) concentrations in influent (AVMet=111,800ng/L, AVGua=1300ng/L) and effluent samples (AVMet=4800ng/L, AVGua=44,000ng/L). To provide a more complete picture of the distribution and potential persistence of these compounds in the German water cycle, a new, efficient and highly sensitive liquid chromatography mass spectrometric method with direct injection was used for the measurement of Metformin and Guanylurea in drinking, surface, sewage and seawater. Limits of quantification (LOQ) ranging from 2-10ng/L allowed the detection of Metformin and Guanylurea in different locations such as: Lake Constance (n=11: AVMet=102ng/L, AVGua=16ng/L), river Elbe (n=12: AVMet=472ng/L, AVGua=9ng/L), river Weser (n=6: AVMet=349ng/L, AVGua=137ng/L) and for the first time in marine North Sea water (n=14: AVMet=13ng/L, AVGua=11ng/L). Based on daily water discharges, Metformin loads of 15.2kg/d (Elbe) and 6.4kg/d (Weser) into the North Sea were calculated. Lake Constance is used to abstract potable water which is further purified to be used as drinking water. A first screening of two tap water samples contained 2ng/L and 61ng/L of Metformin, respectively. The results of this study suggest that Metformin and Guanylurea could be distributed over a large fraction of the world's potable water sources and oceans. With no natural degradation processes, these compounds can be easily reintroduced to humans as they enter the food chain. PMID:24954924

Trautwein, Christoph; Berset, Jean-Daniel; Wolschke, Hendrik; Kümmerer, Klaus

2014-09-01

303

PhET Simulation: The Greenhouse Effect  

NSDL National Science Digital Library

This simulation explores how greenhouse gases affect Earth's climate. Students can view levels of atmospheric greenhouse gases present during Earth's last Ice Age, in the year 1750, today, or some time in the future.....and observe how the Earth's temperature changes. Levels of 4 greenhouse gases are displayed: water, carbon dioxide, methane, and nitrous oxide. Add cloud cover to the simulation and observe the resulting temperature changes. Choose the tab "Glass Layers" to see what happens in an ideal greenhouse model. In the third simulation, students can adjust levels of atmospheric gases, then shoot infrared and visible photons from a photon emitter. How do the gases influence photon absorption? See Related Materials for a comprehensive student guide that explains how to use the "Greenhouse Effect" simulation to conduct a lab experiment. The experimental question: Which atmospheric gas is the best absorber of infrared photons? This item is part of a growing collection of simulations by the Physics Education Technology Project (PhET). Simulations were designed using principles from physics education research and refined based on student interviews and classroom observations.

304

Managing in a federal system without an ‘ultimate arbiter’: Kompetenz-Kompetenz in the EU and the ante-bellum United States  

Microsoft Academic Search

Although an ‘ultimate arbiter’ is generally accepted as a necessary element of a federation, emerging federal systems are often unable to agree on who should play the role. Legally, the debate surrounds the right to monitor the limits of federal and state competences – or the right to Kompetenz-Kompetenz. This article looks at how the early United States and the

Erin Delaney

2005-01-01

305

Analyse der Langzeitsicherheit von Endlagerkonzepten fuer waermeerzeugende radioaktive Abfaelle. (Analysis of the long-term safety of ultimate storage concepts for heat generating radioactive wastes).  

National Technical Information Service (NTIS)

An overall assessment of the studied ultimate storage concepts provides as the best concept in terms of best estimate values pure drift emplacement on three levels with advanced MAW (SL3) conditioning. When MAW and HAW are stored together, there are no co...

D. Buhmann A. Nies R. Storck

1991-01-01

306

"Our Ultimate Competition," a Speech by John Neufeld, and Readers' Responses to Neufeld's "Boys Lie" by Matthew Ellis, Jaime Miller and Liz Ackert.  

ERIC Educational Resources Information Center

Suggests the ultimate competition for writers of contemporary adolescent fiction is life--the world that children inhabit is getting stranger and stranger. Discusses parents' and adolescents' different reactions to the novel "Boys Lie," which addresses the issues of rape and sexual harassment. Presents reactions to the speech and the responses of…

Moore, John Noell, Ed.

2000-01-01

307

Strategies for developing pH sensitive fluorescent probes  

NASA Astrophysics Data System (ADS)

Many physiological processes function efficiently within a well-controlled pH range. Higher acidity level has been implicated with a number of systemic pathologies. The potential of pH sensitive fluorescent probes for reporting on biological environments has been widely utilized in a variety of cell studies and has been recently recognized as a powerful technique for in vivo imaging of diseases associated with elevated acidity level. We present several strategies for the development of pH sensitive probes suitable for in vivo imaging. The strategies include incorporation of pH sensitive functionalities in known fluorophores, synthesis of novel pH sensitive skeletons, and design of pH sensitive nanoparticles using acid-degradable polymers.

Berezin, Mikhail Y.; Guo, Kevin; Lee, Hyeran; Akers, Walter; Almutairi, Adah; Fréchet, Jean M. J.; Achilefu, Samuel

2010-02-01

308

pH dependence of actin self-assembly.  

PubMed Central

Fluorescence enhancement and fluorescence photobleaching recovery have been utilized to examine actin self-assembly over the pH range 6.6-8.0. The kinetics of assembly are faster and the critical concentrations are lower at lower pH. Filament diffusion coefficients are not a function of pH, indicating that average filament lengths are not pH dependent. Although critical actin concentrations are a sensitive function of the concentrations of various cations in the medium, the relative pH dependences of critical concentrations are similar for all combinations of cations employed. The pH dependence of actin self-assembly is sufficiently great that it should be taken into account when comparing data from different reports and when relating in vitro measurements to cytoplasmic mechanisms.

Wang, F; Sampogna, R V; Ware, B R

1989-01-01

309

Spectral Modeling for Accelerated pH Spectroscopy using EPR  

PubMed Central

A data modeling and processing method for electron paramagnetic resonance (EPR)-based pH spectroscopy is presented. The proposed method models the EPR spectrum of a pH-sensitive probe in both protonated and unprotonated forms. Under slow-exchange conditions, the EPR spectrum of a sample with an unknown pH value can be accurately represented by a weighted sum of the two models, with the pH value completely determined by their relative weights. Unlike traditional pH spectroscopy, which relies on locating resonance peaks, the proposed modeling-based approach utilizes the information from the entire scan and hence leads to more accurate estimation of pH for a given acquisition time. By employing the proposed methodology, we expect a reduction in the pH estimation error by more than a factor of three, which represents an order of magnitude reduction in acquisition time compared to the traditional method.

Ahmad, R.; Potter, L.C.; Khramtsov, V.V.

2012-01-01

310

Optical sensor for high pH values  

Microsoft Academic Search

A new optical pH sensor for high pH values has been developed by covalently immobilizing Thiazole Yellow on an optically transparent triacetylcellulose membrane, which had been previously hydrolyzed. The advantageous features of the sensor include (a) the ability to respond at high pH values (12.0–13.5), where glass electrodes show an alkaline error, (b) a rapid equilibration time, (c) high reproducibility,

A Safavi; H Abdollahi

1998-01-01

311

Ambulatory Esophageal pH Monitoring: New Directions  

Microsoft Academic Search

pH testing remains a commonly used evaluative tool in clinical practice. However, the original tool that included a nasally placed pH catheter was plagued with a variety of shortcomings, primarily the effect of the procedure on patients’ lifestyle and thus on reflux-provoking activities. The miniaturization of evaluative techniques in gastroenterology was the impetus for the development of the wireless pH

Ram Dickman; Ronnie Fass

2006-01-01

312

A droplet-based pH regulator in microfluidics.  

PubMed

In this paper, we develop a strategy to form on-demand droplets with specific pH values. The pH control is based on electrolysis of water in microfluidics, and the produced hydrogen and hydroxyl ions are separated and confined in individual containers during the droplet generation, triggered by a pressure pulse. By tuning the applied voltages and pressure pulses, we can control on demand the pH value in a droplet. PMID:24745036

Zhou, Hongbo; Li, Gang; Yao, Shuhuai

2014-06-01

313

Primary state standard for the pH unit  

Microsoft Academic Search

wide utilization of pH measurements started with the application of the glass electrode whose theory was established by Academician B. P. Nikol'skii in 1937. The first instruments with a glass electrode, the pH meters, appeared in the USSR at the end of the fifties. At present more than 100,000 such instruments have been produced. The wide application of pH measurements

M. Yu. Gorina; D. K. Kollerov; L. P. Piskunova

1975-01-01

314

Notes on the Measurement of pH Values  

Microsoft Academic Search

The original definition of pH is: pH = -log a{sub H}. Where a{sub H} is the (relative) hydrogen ion activity. However, a single ion activity cannot be measured. Activities of individual ionic species are necessarily conventional. The pH number, of course, has in itself little absolute significance. As the negative of the logarithm of a product of a concentration (c

R M Carranza; R B Rebak

2005-01-01

315

Quantum dot photoluminescence lifetime-based pH nanosensor.  

PubMed

The first CdSe/ZnS quantum dot photoluminescence lifetime-based pH nanosensor has been developed. The average lifetime of mercaptopropionic acid-capped QD nanosensors showed a linear response in the pH range of 5.2-6.9. These nanosensors have been satisfactorily applied for pH estimation in simulated intracellular media, with high sensitivity and high selectivity toward most of the intracellular components. PMID:21240450

Ruedas-Rama, Maria J; Orte, Angel; Hall, Elizabeth A H; Alvarez-Pez, Jose M; Talavera, Eva M

2011-03-14

316

A profound analysis of Rb2[PH] and Cs2[PH] and the role of [PH]2- ions during temperature-induced solid-solid phase transitions  

NASA Astrophysics Data System (ADS)

The temperature-induced solid-solid transformation of Rb2[PH] and Cs2[PH] is characterized from both experiment and theory. Neutron diffraction, IR-spectroscopy and ab-initio molecular dynamics simulations reveal an asymmetric shift of the lattice constants at 80 K. The molecular mechanism of the structural transformation as identified from IR-spectroscopy and ab-initio molecular dynamics simulations is closely connected to the orientation of the [PH]2- moieties which undergo a partial order-disorder phase transition.

Somer, M.; Schnering, H. G. v.; Hochrein, O.; Zahn, D.

2014-06-01

317

Influence of the Kingak Shale ultimate shelf margin on frontal structures of the Brooks Range in the National Petroleum Reserve in Alaska  

USGS Publications Warehouse

The Jurassic–Lower Cretaceous Kingak Shale in the National Petroleum Reserve in Alaska (NPRA) includes several southward-offlapping depositional sequences that culminate in an ultimate shelf margin, which preserves the depositional profile in southern NPRA. The Kingak Shale thins abruptly southward across the ultimate shelf margin and grades into condensed shale, which is intercalated with underlying condensed shale and chert of the Upper Triassic Shublik Formation and overlying condensed shale of the Lower Cretaceous pebble shale unit and the gamma-ray zone (GRZ) of the Hue Shale. This composite of condensed shale forms a thin (?300-meter) and mechanically weak section between much thicker and mechanically stronger units, including the Sadlerochit and Lisburne Groups below and the sandstone-prone foredeep wedge of the Torok Formation above. Seismic interpretation indicates that the composite condensed section acted as the major detachment during an Early Tertiary phase of deformation in the northern foothills of the Brooks Range and that thrust faults step up northward to the top of the Kingak, or to other surfaces within the Kingak or the overlying Torok. The main structural style is imbricate fault-bend folding, although fault-propagation folding is evident locally, and large-displacement thrust faults incorporate backthrusting to form structural wedges. The Kingak ultimate shelf margin served as a ramp to localize several thrust faults, and the spatial relationship between the ultimate shelf margin and thrust vergence is inferred to have controlled many structures in southern NPRA. For example, the obliqueness of the Carbon Creek anticline relative to other structures in the foothills is the result of northward-verging thrust faults impinging obliquely on the Kingak ultimate shelf margin in southwestern NPRA.

Stier, Natalie E.; Connors, Christopher D.; Houseknecht, David W.

2014-01-01

318

Development of pH Responsive Fluorescent False Neurotransmitters  

PubMed Central

We introduce pH responsive fluorescent false neurotransmitters (pH responsive FFNs) as novel probes that act as vesicular monoamine transporter (VMAT) substrates and ratiometric fluorescent pH sensors. The development of these agents was achieved by systematic molecular design that integrated several structural elements, including the aminoethyl group (VMAT recognition), halogenated hydroxycoumarin core (ratiometric optical pH sensing in the desired pH range), and N- or C-alkylation (modulation of lipophilicity). Of fourteen compounds that were synthesized, the probe Mini202 was selected based on the highest uptake in VMAT2-transfected HEK cells and desirable optical properties. Using Mini202, we measured the pH of catecholamine secretory vesicles in PC-12 cells (pH ~ 5.9) via two-photon fluorescence microscopy. Incubation with methamphetamine led to an increase in vesicular pH (pH ~ 6.4), consistent with a proposed mechanism of action of this psychostimulant, and eventually to redistribution of vesicular content (including Mini202) from vesicles to cytoplasm. Mini202 is sufficiently bright, photostable and suitable for two-photon microscopy. This probe will enable fundamental neuroscience and neuroendocrine research as well as drug screening efforts.

Lee, Minhee; Gubernator, Niko G.; Sulzer, David; Sames, Dalibor

2010-01-01

319

pH dependence of drug-membrane interaction  

NASA Astrophysics Data System (ADS)

Langmuir monolayer technique has been used to understand the interaction of piroxicam, a NSAID of oxicam class with the DMPC half membrane. It has been found that drug-membrane interaction is dependent on the pH of the environment. The interaction slightly increases with pH in the range 2.5-6.5 whereas the interaction becomes stronger in the pH range 6.6-8.5. The mechanism of interaction has been explained considering the pH dependent molecular conformation and ionic state of drug and lipid molecules.

Basak, Uttam Kumar; Datta, Alokmay

2014-04-01

320

Field measurement of alkalinity and pH  

USGS Publications Warehouse

The behavior of electrometric pH equipment under field conditions departs from the behavior predicted from Nernst's law. The response is a linear function of pH, and hence measured pH values may be corrected to true pH if the instrument is calibrated with two reference solutions for each measurement. Alkalinity titrations may also be made in terms of true pH. Standard methods, such as colorimetric titrations, were rejected as unreliable or too cumbersome for rapid field use. The true pH of the end point of the alkalinity titration as a function of temperature, ionic strength, and total alkalinity has been calculated. Total alkalinity in potable waters is the most important factor influencing the end point pH, which varies from 5.38 (0 ? C, 5 ppm (parts per million) HC0a-) to 4.32 (300 ppm HC0a-,35 ? C), for the ranges of variables considered. With proper precautions, the pH may be determined to =i:0.02 pH and the alkalinity to =i:0.6 ppm HCO3- for many naturally occurring bodies of fresh water.

Barnes, Ivan

1964-01-01

321

Marine teleost locates live prey through pH sensing.  

PubMed

We report that the Japanese sea catfish Plotosus japonicus senses local pH-associated increases in H(+)/CO2 equating to a decrease of ?0.1 pH unit in ambient seawater. We demonstrated that these sensors, located on the external body of the fish, detect undamaged cryptic respiring prey, such as polychaete worms. Sensitivity is maximal at the natural pH of seawater (pH 8.1 to 8.2) and decreases dramatically in seawater with a pH <8.0. PMID:24904164

Caprio, John; Shimohara, Mami; Marui, Takayuki; Harada, Shuitsu; Kiyohara, Sadao

2014-06-01

322

Molecular aspects of bacterial pH sensing and homeostasis  

PubMed Central

Diverse mechanisms for pH-sensing and cytoplasmic pH homeostasis enable most bacteria to tolerate or grow at external pH values that are outside the cytoplasmic pH range they must maintain for growth. The most extreme cases are exemplified by the extremophiles that inhabit environments whose pH is below 3 or above 11. Here we describe how recent insights into the structure and function of key molecules and their regulators reveal novel strategies of bacterial pH-homeostasis. These insights may help us better target certain pathogens and better harness the capacities of environmental bacteria.

Krulwich, Terry A.; Sachs, George; Padan, Etana

2011-01-01

323

Microscale pH regulation by splitting water  

PubMed Central

We present a simple, flexible approach for pH regulation in micro-chambers by injecting controllable amounts of protons and hydroxide ions via field-enhanced dissociation of water molecules. Under a DC voltage bias, the polymeric bipolar membranes integrated in microfluidics devices generate and separate H+ and OH? ions without gas production or contaminant generation resulting from electron-transfer reactions. Robust local on-chip pH and pH gradients are sustained with no need of additional acidic?basic solutions that dilute analyte concentrations. The method could provide a better strategy for pH control in microfluidics.

Cheng, Li-Jing; Chang, Hsueh-Chia

2011-01-01

324

Rhizosphere pH dynamics in trace-metal-contaminated soils, monitored with planar pH optodes  

Microsoft Academic Search

The present study presents new insights into pH dynamics in the rhizosphere of alpine pennycress (Noccaea caerulescens (J. Presl & C. Presl) F.K. Mey), maize (Zea mays\\u000a L.) and ryegrass (Lolium perenne\\u000a L.), when growing on three soils contaminated by trace metals with initial pH values varying from 5.6 to 7.4. The pH dynamics\\u000a were recorded, using a recently developed

Stephan Blossfeld; Jérôme Perriguey; Thibault Sterckeman; Jean-Louis Morel; Rainer Lösch

2010-01-01

325

Chondrocytes, synoviocytes and dermal fibroblasts all express PH20, a hyaluronidase active at neutral pH  

Microsoft Academic Search

Hyaluronan (HA), an important component of connective tissues, is highly metabolically active, but the mechanisms involved in its catabolism are still largely unknown. We hypothesized that a protein similar to sperm PH-20, the only mammalian hyaluronidase known to be active at neutral pH, could be expressed in connective tissue cells. An mRNA transcript similar to that of PH-20 was found

Hafida El Hajjaji; Ada Asbury Cole; Daniel-Henri Manicourt

2005-01-01

326

Extracellular pH modulates GABAergic neurotransmission in rat hypothalamus.  

PubMed

Changes in extracellular pH have a modulatory effect on GABAA receptor function. It has been reported that pH sensitivity of the GABA receptor is dependent on subunit composition and GABA concentration. Most of previous investigations focused on GABA-evoked currents, which only reflect the postsynaptic receptors. The physiological relevance of pH modulation of GABAergic neurotransmission is not fully elucidated. In the present studies, we examined the influence of extracellular pH on the GABAA receptor-mediated inhibitory neurotransmission in rat hypothalamic neurons. The inhibitory postsynaptic currents (IPSCs), tonic currents, and the GABA-evoked currents were recorded with whole-cell patch techniques on the hypothalamic slices from Sprague-Dawley rats at 15-26 postnatal days. The amplitude and frequency of spontaneous GABA IPSCs were significantly increased while the external pH was changed from 7.3 to 8.4. In the acidic pH (6.4), the spontaneous GABA IPSCs were reduced in amplitude and frequency. The pH induced changes in miniature GABA IPSCs (mIPSCs) similar to that in spontaneous IPSCs. The pH effect on the postsynaptic GABA receptors was assessed with exogenously applied varying concentrations of GABA. The tonic currents and the currents evoked by sub-saturating concentration of GABA ([GABA]) (10?M) were inhibited by acidic pH and potentiated by alkaline pH. In contrast, the currents evoked by saturating [GABA] (1mM) were not affected by pH changes. We also investigated the influence of pH buffers and buffering capacity on pH sensitivity of GABAA receptors on human recombinant ?1?2?2 GABAA receptors stably expressed in HEK 293 cells. The pH influence on GABAA receptors was similar in HEPES- and MES-buffered media, and not dependent on protonated buffers, suggesting that the observed pH effect on GABA response is a specific consequence of changes in extracellular protons. Our data suggest that the hydrogen ions suppress the GABAergic neurotransmission, which is mediated by both presynaptic and postsynaptic mechanisms. PMID:24780768

Chen, Z-L; Huang, R-Q

2014-06-20

327

Biomedical PhD education--an international perspective.  

PubMed

The PhD, otherwise known as the doctor of philosophy or Dr. Phil., is an internationally recognized degree, indicating that the PhD graduate has received training in research under supervision. Traditionally, the PhD was the route to an academic career, with most successful PhD graduates receiving tenured university positions. However, over the past 20-30 years, and particularly the past 10 years, the situation has changed dramatically. Governments in many countries have invested massively in PhD education, believing that trained researchers will contribute to the 'knowledge society', and thus increase the competitiveness of their countries in the future economies of the world. Thus, only a small fraction of PhD graduates now end up in academic research. Yet, the PhD remains a research degree, and indeed, institutions have become heavily dependent on PhD students for their research output. The situation has thus created a paradox. On the one hand, it has become essential for institutions to have many PhD students and for the research performed to be of the highest level. On the other hand, the careers of PhD students are not necessarily going to be directly related to the research performed during their PhD studies. The purpose of this article is to explore how this seeming paradox is being addressed in biomedicine and to show that far from being inconsistent that the two aspects are in fact complementary. The article is based on the author's experience as Head of Aarhus Graduate School of Health Sciences 2002-2011 and his work with graduate schools across Europe and internationally through the organization ORPHEUS. PMID:23461869

Mulvany, Michael J

2013-05-01

328

The Early Development of Electronic pH Meters  

ERIC Educational Resources Information Center

A 19-year-old undergraduate at the University of Chicago, Kenneth Goode, in 1921 came up with the idea of an electronic pH meter, worked out some of its initial problems, and set in motion an international scientific effort that culminated in the current, wide availability of electronic pH meters. Except for the replacement of vacuum tubes by…

Hines, Wallis G.; de Levie, Robert

2010-01-01

329

Predicting Computer Science Ph.D. Completion: A Case Study  

ERIC Educational Resources Information Center

This paper presents the results of an analysis of indicators that can be used to predict whether a student will succeed in a Computer Science Ph.D. program. The analysis was conducted by studying the records of 75 students who have been in the Computer Science Ph.D. program of the University of Alabama in Huntsville. Seventy-seven variables were…

Cox, G. W.; Hughes, W. E., Jr.; Etzkorn, L. H.; Weisskopf, M. E.

2009-01-01

330

Effect of pH on biological phosphorus uptake.  

PubMed

An anaerobic aerobic laboratory scale sequencing batch reactor (SBR) was operated to study the effect of pH on enhanced biological phosphorus removal. Seven steady states were achieved under different operating conditions. In all of them, a slight variation in the pH value was observed during anaerobic phase. However, pH rose significantly during aerobic phase. The increase observed was due to phosphorus uptake and carbon dioxide stripping. When pH was higher than 8.2-8.25 the phosphorus uptake rate clearly decreased. The capability of Activated Sludge Model No. 2d (ASM2d) and Biological Nutrient Removal Model No. 1 (BNRM1) to simulate experimental results was evaluated. Both models successfully characterized the enhanced biological phosphorus removal performance of the SBR. Furthermore, BNRM1 also reproduced the pH variations observed and the decrease in the phosphorus uptake rate. This model includes a switch function in the kinetic expressions to represent the pH inhibition in biological processes. The pH inhibition constants related to polyphosphate storage process were obtained by adjusting model predictions to measured phosphorus concentrations. On the other hand, pH inhibition should be included in ASM2d to accurately simulate experimental phosphorus evolution observed in an A/O SBR. PMID:16958137

Serralta, J; Ferrer, J; Borrás, L; Seco, A

2006-12-01

331

Optical fibre PH sensor based on immobilized indicator  

Microsoft Academic Search

An optical fiber pH sensor which has the immobilized pH sensitive indicator dye reagents on the tip of the optical fiber has been studied. The probe is made by covalently immobilizing the phenol red, bromine phenol blue, or bromothymol blue on the polyacrylamide microsphere fixed by polyterafluoroethylene (PTFE) film. A gap between the dye and optical fiber was used to

Defu Cai; Qiang Cao; Jinghong Han; Jine Cai; Yating Li; Zemin Zhu; Jie Fan; Ning Gao

1991-01-01

332

pH sensitivity of epidermal growth factor receptor complexes.  

PubMed

The association/dissociation binding kinetics of 125I-labeled mouse epidermal growth factor (EGF) to receptors on human fibroblast cells in monolayer culture have been measured at 4 degrees C as a function of extracellular pH from pH 5-9. At pH 8, steady-state total binding is maximal. As pH is lowered to 6.5, total binding monotonically decreases dramatically. It changes further only slightly between pH 6.5 and 5 to about 20% of the maximum binding value. Scatchard binding plots at pH 7.5 and above show the commonly observed concave-upward, non-linear curve; as pH is lowered, this plot becomes much more linear, indicating that the "high affinity" bound receptor population is greatly diminished. Application of our ternary complex binding model [Mayo et al., J Biol Chem 264:17838-17844, 1989], which hypothesizes complexation of the EGF-bound receptor with a cell surface interaction molecule, indicates that pH may have some direct effects on ternary complex formation, but the major effect is on EGF-receptor dissociation. PMID:8501133

Nunez, M; Mayo, K H; Starbuck, C; Lauffenburger, D

1993-03-01

333

What if We Made Fewer Ph.D.'s?  

ERIC Educational Resources Information Center

Whenever a discussion opens about nonacademic employment for Ph.D.s, it is not long before someone suggests reducing graduate-school admissions. "The market for full-time scholars has fallen off a cliff lately," this argument goes, "so why not just train fewer of them?" The strategy to reduce the number of Ph.D. students recurs in those…

Cassuto, Leonard

2012-01-01

334

State primary standard for the pH scale  

Microsoft Academic Search

Information is given on the state primary standard for the pH scale that has been set up at VNIIFTRI. The measurement system\\u000a is described and certification results are given. The future development of pH measurement in Russia is considered.

N. N. Zdorikov; O. V. Karpov; I. I. Maksimov; E. E. Seiku

1998-01-01

335

Teaching Ph.D.'s How to Reach Out  

ERIC Educational Resources Information Center

Marc Aronson, a lecturer in the School of Communication and Information at Rutgers University at New Brunswick and a historian who writes books for young adults, recently suggested that all Ph.D. candidates be required to take a course he calls "Communications." The goal would be to teach Ph.D.'s--both would-be academics and those who will pursue…

Cassuto, Leonard

2012-01-01

336

Rethinking PhD Learning Incorporating Communities of Practice  

ERIC Educational Resources Information Center

This paper grows from research which focuses on the learning characteristics of PhD students, incorporating communities of practice both during their studies and beyond completion of their PhD, and drawing on theories of adult learning and lifelong learning. It shows how professional discourse enhances academic discourse through student engagement…

Shacham, Miri; Od-Cohen, Yehudit

2009-01-01

337

The Ph.D. Surplus - Realities and Illusions.  

ERIC Educational Resources Information Center

Every 6 years the number of Ph.D.'s produced doubles. At this point about 1 percent of the babies born 27 years ago gets a Ph.D. This production rate will probably increase to 6 percent of the adult population. With the present situation in higher education, which includes an average retirement after 40 years of service, the supply already…

Hansen, Harold P.

338

PhDs in Australia, from the Beginning  

ERIC Educational Resources Information Center

The Australian PhD is a relatively recent phenomenon, the first three being awarded in 1948. Before that, most Australian scholars typically went to Britain (predominantly) or the USA to undertake their doctoral studies. The aim of this research note is to provide a brief statistical history of the Australian PhD, noting changes over time between…

Dobson, Ian R.

2012-01-01

339

Regulation of Vacuolar pH in Citrus Limon.  

National Technical Information Service (NTIS)

The primary objective of this grant was to characterize the vacuolar V-ATPase of lemon fruits. Lemon fruit vacuoles have an internal pH of about 2.5. Since a typical plant vacuole has a luminal pH of around 5.5, the lemon fruit V-APTase must have special ...

2005-01-01

340

Production of Leuconostoc oenos Biomass under pH Control †  

PubMed Central

Leuconostoc oenos was grown on apple juice-based media. The effect of pH control on metabolism and biomass production was studied. Without pH control, L. oenos acidified the apple juice media to approximately pH 3.6. More than 75% of the malic acid was used under these conditions, but less than half of the carbohydrates was assimilated. Under pH control, biomass yields increased by 60%; most of the malic acid was used, but high levels of unfermented carbohydrates remained. The addition of tomato juice, vitamins, nucleotides, Mn+, and malic acid did not permit further increases in the cell counts; however, malic acid did induce further acidification. Growth without pH control favored a more homofermentative metabolism. Biomass production was higher in filter-sterilized apple juice media compared with that in the autoclaved media.

Champagne, Claude P.; Gardner, Nancy; Doyon, Gilles

1989-01-01

341

MERIT Award Recipient: Stephen P. Goff, Ph.D.  

Cancer.gov

The Goff laboratory is interested in the replication of a simple retrovirus, the Moloney murine leukemia virus, and the interaction of the virus with the host. The ultimate goal of the research is to determine the roles of each of the viral proteins in the complex viral life cycle, and to identify the impact of these proteins on host cellular machinery.

342

Signal-dependent membrane targeting by pleckstrin homology (PH) domains.  

PubMed Central

Pleckstrin homology (PH) domains are small protein modules of around 120 amino acids found in many proteins involved in cell signalling, cytoskeletal rearrangement and other processes. Although several different protein ligands have been proposed for PH domains, their only clearly demonstrated physiological function to date is to bind membrane phosphoinositides. The PH domain from phospholipase C-delta(1) binds specifically to PtdIns(4,5)P(2) and its headgroup, and has become a valuable tool for studying cellular PtdIns(4,5)P(2) functions. More recent developments have demonstrated that a subset of PH domains recognizes the products of agonist-stimulated phosphoinositide 3-kinases. Fusion of these PH domains to green fluorescent protein has allowed dramatic demonstrations of their independent ability to drive signal-dependent recruitment of their host proteins to the plasma membrane. We discuss the structural basis for this 3-phosphoinoistide recognition and the role that it plays in cellular signalling. PH domains that bind specifically to phosphoinositides comprise only a minority (perhaps 15%) of those known, raising questions as to the physiological role of the remaining 85% of PH domains. Most (if not all) PH domains bind weakly and non-specifically to phosphoinositides. Studies of dynamin-1 have indicated that oligomerization of its PH domain may be important in driving membrane association. We discuss the possibility that membrane targeting by PH domains with low affinity for phosphoinositides could be driven by alteration of their oligomeric state and thus the avidity of their membrane binding.

Lemmon, M A; Ferguson, K M

2000-01-01

343

pH homeostasis in promyelocytic leukemic HL60 cells  

PubMed Central

By measuring the membrane potential using the influx of the lipophilic cation tetraphenylphosphonium and intracellular pH using 2,7-biscarboxy- ethyl-5(6)-carboxyfluorescein and the distribution of the weak acid 5,5- dimethyl-2,4-oxazolidinedione, we have determined that intracellular pH is 0.9-1.1 pH units above electrochemical equilibrium in undifferentiated HL60 cells, indicating that these cells actively extrude proton equivalents. The Na/H exchanger is not the system responsible for keeping the pH above the electrochemical equilibrium, since adding inhibitors of this transport system (dimethylamiloride and ethylisopropylamiloride) or removing the extracellular sodium has no effect on intracellular pH. In contrast, the addition of the Cl/HCO3 exchange inhibitors H2 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) or pentachlorophenol (PCP) causes a drop in intracellular pH, and the removal of extracellular chloride in the presence of bicarbonate leads to a large intracellular alkalinization, which indicates a role for the anion exchanger in pH homeostasis in these cells. In addition, we find that the intracellular chloride concentration is about one order of magnitude above electrochemical equilibrium. We conclude that an H2DIDS and PCP inhibitable system, probably the Cl/HCO3 exchanger, is at least partially responsible for keeping intracellular pH above electrochemical equilibrium in HL60 cells under resting conditions. We also find no change in intracellular pH when cells differentiate along the granulocytic pathway (having been induced by the addition of dimethylsulfoxide or of retinoic acid), which indicates that changes in intracellular pH are not causally related to cell differentiation.

1988-01-01

344

Plant based dietary supplement increases urinary pH  

PubMed Central

Background Research has demonstrated that the net acid load of the typical Western diet has the potential to influence many aspects of human health, including osteoporosis risk/progression; obesity; cardiovascular disease risk/progression; and overall well-being. As urinary pH provides a reliable surrogate measure for dietary acid load, this study examined whether a plant-based dietary supplement, one marketed to increase alkalinity, impacts urinary pH as advertised. Methods Using pH test strips, the urinary pH of 34 healthy men and women (33.9 +/- 1.57 y, 79.3 +/- 3.1 kg) was measured for seven days to establish a baseline urinary pH without supplementation. After this initial baseline period, urinary pH was measured for an additional 14 days while participants ingested the plant-based nutritional supplement. At the end of the investigation, pH values at baseline and during the treatment period were compared to determine the efficacy of the supplement. Results Mean urinary pH statistically increased (p = 0.03) with the plant-based dietary supplement. Mean urinary pH was 6.07 +/- 0.04 during the baseline period and increased to 6.21 +/- 0.03 during the first week of treatment and to 6.27 +/- 0.06 during the second week of treatment. Conclusion Supplementation with a plant-based dietary product for at least seven days increases urinary pH, potentially increasing the alkalinity of the body.

Berardi, John M; Logan, Alan C; Rao, A Venket

2008-01-01

345

Ultimate emulsion and its applications: a laboratory-made silver halide emulsion of optimized quality for monochromatic pulsed and full-color holography  

NASA Astrophysics Data System (ADS)

A ultra-high sensitivity holographic Ultimate emulsion (10nm grains) has been produced, which allows the realization with short exposure times of bright, large sized, with wide view angle and full color holograms of fragile still subjects of monochromatic pulsed reflection holograms of alived subjects. The high transparency of Ultimate emulsions as color transmission holograms makes them highly suitable for mastering, the copies keeping the same performances as the master. Copies on other materials, especially polymer emulsions are possible. Coating machines have been performed for the production of 36 x 44 cm triacetate films and 60 x 84 cm glass plates under controlled conditions of temperature and humidity. Also, a homemade portable camera with pulsed YLF or ruby lasers allows to realize holograms in situ of alive subjects on H1 transmission holograms up to 60 x80 cm and instant H2 reflection copies up to 30 x 40 cm. Some examples of holograms are displayed.

Gentet, Yves; Gentet, Philippe

2000-10-01

346

Removal of the cortical endplates has little effect on ultimate load and damage distribution in QCT-based voxel models of human lumbar vertebrae under axial compression.  

PubMed

Every year, 500,000 osteoporotic vertebral compression fractures occur in Europe. Quantitative computed tomography (QCT)-based finite element (FE) voxel models predict ultimate force whether they simulate vertebral bodies embedded in polymethylmethacrylate (PMMA) or vertebral sections with both endplates removed. To assess the effect of endplate removal in those predictions, non-linear FE analyses of QCT-based voxel models of human vertebral bodies were performed. High resolution pQCT images of 11 human lumbar vertebrae without posterior elements were coarsened to clinical resolution and bone volume fraction was used to determine the elastic, plastic and damage behavior of bone tissue. Three model boundary conditions (BCs) were chosen: the endplates were cropped (BC1, BC2) or voxel layers were added on the intact vertebrae to mimic embedding (BC3). For BC1 and BC3, the bottom nodes were fully constrained and the top nodes were constrained transversely while both node sets were freed transversely for BC2. Axial displacement was prescribed to the top nodes. In each model, we compared ultimate force and damage distribution during post-yield loading. The results showed that ultimate forces obtained with BC3 correlated perfectly with those computed with BC1 (R(2)=0.9988) and BC2 (R(2)=0.9987), but were in average 3.4% lower and 6% higher respectively. Moreover, good correlation of damage distribution calculated for BC3 was found with those of BC1 (R(2)=0.92) and BC2 (R(2)=0.73). This study demonstrated that voxel models of vertebral sections provide the same ultimate forces and damage distributions as embedded vertebral bodies, but with less preprocessing and computing time required. PMID:22503577

Maquer, Ghislain; Dall'Ara, Enrico; Zysset, Philippe K

2012-06-01

347

Career Outcomes for Astronomy Ph.D. Graduates of the University of Texas at Austin: The Next Generation  

NASA Astrophysics Data System (ADS)

Sixteen years ago I conducted a survey of the career trajectories and outcomes of 78 individuals who earned Ph.D.s from the Department of Astronomy at the University of Texas at Austin during the period 1984-1995 (Dinerstein, H. 1996, AAS, 189.0501). In the current poster I extend these statistics up to the present, adding 68 Ph.D. recipients from 1996-2010. This is a sufficiently large sample to search for secular trends such as possible changes in duration of the postdoctoral stage, redistribution of demographics among different kinds of long-term positions, and the emergence of new categories of astronomy-related employment. The picture is less discouraging than one might expect. As of 2010, about 75% of the Texas graduates 7 - 14 years past the Ph.D. are still doing astronomy, and most of those in non-astronomical careers left the field by choice (and often have had considerable success in their alternate careers). Of those 6 years or less past the Ph.D., 50% were in postdoctoral positions and less than 10% had left astronomy. Recent reconsiderations of the employment market (Metcalfe, T.S. 2008, PASP, 120, 229; Seth, A. 2009, Astro2010: The Astronomy and Astrophysics Decadal Survey, Position Paper No. 51) make the point that a typical astronomer who ultimately achieves a permanent position will have held two or three prior temporary positions; this was equally true three decades ago. There has been notable growth nationwide in the number of astronomers employed as faculty at small liberal arts colleges and other undergraduate-centered institutions, a trend that to some degree was anticipated by the University of Texas cohort, which included a number of students for whom this was their personal goal. In a world where job certainty is no longer so prevalent, motivated and resourceful astronomers are finding ways to remain active members of our community.

Dinerstein, Harriet L.

2011-01-01

348

What is the pH at ice surfaces?  

NASA Astrophysics Data System (ADS)

Despite its importance, the effective pH of sea-ice surfaces is not well known. Studying the pH of ice surfaces represents a significant experimental challenge. We studied the pH at the surface of frozen aqueous samples was studied using glancing-angle Laser-induced fluorescence (LIF), a surface-sensitive spectroscopic technique. The fluorescent molecules acridine and harmine were used as pH-sensitive probes: the neutral and cationic forms give rise to fluorescence maxima at different wavelengths, and thus the relative intensities of the neutral and cationic features in the fluorescence spectra can be used to infer local pH. We present results from a study in which we probed pH at the surface of frozen water samples a) whose pre-freezing pH was adjusted using HNO3, HCl or NaOH and b) before and after the deposition of gas-phase HCl to the ice surface. Our results suggests that protons are not enhanced at the ice surface. We also present preliminary results from our studies of the pH at the surface of frozen sea-water samples. This study has important implications for understanding pH-sensitive heterogeneous processes occurring on ice, particularly bromide activation, which is thought to occur on frozen sea-water surfaces and may be proton-mediated.

Wren, S. N.; Donaldson, D. J.

2011-12-01

349

Optical fibre PH sensor based on immobilized indicator  

NASA Astrophysics Data System (ADS)

An optical fiber pH sensor which has the immobilized pH sensitive indicator dye reagents on the tip of the optical fiber has been studied. The probe is made by covalently immobilizing the phenol red, bromine phenol blue, or bromothymol blue on the polyacrylamide microsphere fixed by polyterafluoroethylene (PTFE) film. A gap between the dye and optical fiber was used to make the diffusion of the hydrogen ions easier. The parameters of the optical fiber pH sensor have been given completely. The ranges of measurement are 3.0 - 5.0 pH, 7.0 - 8.5 pH, and 8.0 - 10.0 pH for bromine phenol blue, phenol red, and bromothymol blue, respectively. The sensitivity is 66.6 mV/pH. The probe has a precision of better than 0.55 pH. The linear correlation coefficient is 0.999. The response time is 1 - 2 min. The hysteresis is 0.52%. The repeatability is 0.013 mV, while the stability is 0.015 pH/h.

Cai, Defu; Cao, Qiang; Han, Jinghong; Cai, Jine; Li, Yating; Zhu, Zemin; Fan, Jie; Gao, Ning

1991-08-01

350

PhET Teacher Ideas & Activities: Wave Clicker Questions  

NSDL National Science Digital Library

This page contains a set of 67 concept (clicker) questions with answer key on the topic of waves, available for free download in Power Point or pdf format. It is a PhET Gold Star award-winning resource, developed for use with PhET interactive simulations on waves. Concept questions are intended to introduce a topic and probe students' existing beliefs prior to formal instruction. Students discuss their viewpoints, then "vote" on the correct response to the concept question. The use of concept questions has been extensively tested by physics education researchers and correlated with improved learner outcomes. The clicker questions were created specifically to supplement the following PhET simulations: Fourier: Making Waves, Sound, Wave on a String, Wave Interference, Geometric Optics, and Resonance. This resource is part of a set of teacher-created materials developed to supplement the PhET collection of interactive physics simulations.

Project, The P.; Loeblein, Trish

351

Stress-Corrosion Cracking in Martensitic PH Stainless Steels  

NASA Technical Reports Server (NTRS)

Precipitation-hardening alloys evaluated in marine environment tests. Report describes marine-environment stress-corrosion cracking (SCC) tests of three martensitic precipitation hardening (PH) stainless-steel alloys.

Humphries, T.; Nelson, E.

1984-01-01

352

Micromechanical cantilever as an ultrasensitive pH microsensor  

NASA Astrophysics Data System (ADS)

We report on a pH sensor with ultrahigh sensitivity based on a microcantilever structure with a lithographically-defined crosslinked copolymeric hydrogel. Silicon-on-insulator wafers were used to fabricate cantilevers on which a polymer consisting of poly(methacrylic acid) (PMAA) with poly(ethylene glycol) dimethacrylate was patterned using free-radical UV polymerization. As the pH around the cantilever was increased above the pKa of PMAA, the polymer network expanded and resulted in a reversible change in surface stress causing the microcantilever to bend. Excellent mechanical amplification of polymer swelling as a function of pH change within the dynamic range was obtained, with a maximum deflection sensitivity of 1 nm/5×10-5 ?pH.

Bashir, R.; Hilt, J. Z.; Elibol, O.; Gupta, A.; Peppas, N. A.

2002-10-01

353

ChemTeacher Resource: PhET Balloons and Buoyancy  

NSDL National Science Digital Library

This simulator expands on the PhET Gas Laws simulator. In addition to controlling the pressure, volume, temperature, and number of particles, students can now control balloons and other objects and balance pressures inside and outside of the object.

Colorado, Phet I.

2011-01-01

354

pH Paper (ChemPages Lab)  

NSDL National Science Digital Library

pH Paper: this is a resource in the collection "ChemPages Laboratory Resources". The approximate pH of a solution can be determined by placing a drop of the solution on a piece of indicator paper. Two types of pH paper are commonly used: litmus paper and universal (Alkacid) paper. The type of pH paper used is dependent on the type of measurement and degree of accuracy required. The ChemPages Laboratory Resources are a set of web pages that include text, images, video, and self check questions. The topics included are those that are commonly encountered in the first-year chemistry laboratory. They have been put together for use as both a pre-laboratory preparation tool and an in-laboratory reference source.

355

PhET Teacher Ideas: Build An Atom  

NSDL National Science Digital Library

This is a lesson plan developed specifically to accompany the PhET simulation Build An Atom. Created by a PhET "Gold-Star" teacher, the lesson contains a complete student guide in printable pdf format, and pre-lab/post-lab assessments. By following the student guide, learners will be able to create models of stable and unstable atoms, identify elements and their position on the periodic table, and determine if a model depicts a neutral atom or an ion. The atom builder simulation, which must be open and displayed to complete this activity, is available from PhET at: Build An Atom. This item is part of a larger collection of simulations developed by the Physics Education Technology project (PhET).

Loeblein, Trish

2011-07-13

356

DCEG Seminar in February: Michael Cook, Ph.D.  

Cancer.gov

February 27, 2014 10:30 AM - 11:30 AM + Add to Outlook Calendar Speaker Michael Blaise Cook, Ph.D. Investigator, Hormonal and Reproductive Epidemiology Branch Division of Cancer Epidemiology and Genetics, National Cancer Institute Title Epidemiologic

357

Commentary: PhDs in Biochemistry Education--5 Years Later  

ERIC Educational Resources Information Center

In this commentary, the discussion of PhDs in biochemistry education research is expanded to explore a number of diverse pathways leading to a competitive research program in biochemistry education research.

Offerdahl, Erika G.; Momsen, Jennifer L.; Osgood, Marcy

2014-01-01

358

Strategies for developing pH sensitive fluorescent probes  

Microsoft Academic Search

Many physiological processes function efficiently within a well-controlled pH range. Higher acidity level has been implicated with a number of systemic pathologies. The potential of pH sensitive fluorescent probes for reporting on biological environments has been widely utilized in a variety of cell studies and has been recently recognized as a powerful technique for in vivo imaging of diseases associated

Mikhail Y. Berezin; Kevin Guo; Hyeran Lee; Walter Akers; Adah Almutairi; Jean M. J. Fréchet; Samuel Achilefu

2010-01-01

359

Ambulatory 24-hour esophageal pH monitoring  

Microsoft Academic Search

If 24-hour esophageal pH monitoring is to be a useful diagnostic tool, it must reliably discriminate gastroesophageal reflux patients despite daily variations in distal esophageal acid exposure. To address this issue, we studied 53 subjects (14 healthy normals, 14 esophagitis patients, and 25 patients with atypical symptoms) with two ambulatory pH tests performed within 10 days of each other. Intrasubject

G. J. Wiener; T. M. Morgan; J. B. Copper; D. O. Castell; J. W. Sinclair; J. E. Richter

1988-01-01

360

Improving the quality of potentiometric pH measurements  

Microsoft Academic Search

Like all experimentally determined physical and chemical properties, pH measurements are affected by the limited precision\\u000a and accuracy of the measurement procedures. Fundamental studies of pH standards, based on measurement of the potential of\\u000a an electrochemical cell without transference, known as the Harned cell, containing a platinum–hydrogen electrode and a silver–silver\\u000a chloride reference electrode, indicate that vapour condensation phenomena on

M. J. Guiomar; H. M. Lito; M. Filomena Camões; Catarina M. Viçoso

2007-01-01

361

Wireless pH capsule--yield in clinical practice.  

PubMed

Wireless pH monitoring is one of the recent technologies that focus on improving the diagnosis of gastroesophageal reflux disease (GERD). The capsule, which is fixed within the esophagus, transmits data via telemetry to an external receiver. The capsule is usually inserted 6 cm above the squamocolumnar junction during an upper endoscopy. The standard recording duration is 48 hours but this can be extended to 96 hours. The wireless capsule has been shown to be at least as accurate as the conventional catheter for the monitoring of esophageal pH. Normal pH values have been established in three different series. The use of a wireless capsule provides an increased diagnostic yield for GERD compared with the conventional catheter. The increased yield is the result of higher sensitivity to detect both abnormal acid esophageal exposure and positive symptom-reflux association. This may be related both to the prolonged recording duration and to fewer dietary modifications and restrictions on activities. Several studies have shown that the pH capsule was better tolerated by patients than the conventional pH catheter. Mild-to-moderate chest pain represents the main side effect of the pH capsule: severe chest pain requiring endoscopic removal of the capsule is rare. The main indication for wireless capsule application is monitoring of distal esophageal pH for diagnostic purpose, particularly in patients with a normal endoscopic examination. The capsule technique has some limitations: costs are higher than conventional pH monitoring, misplacement may occur, and the sampling rate is lower. Finally, compared with pH-impedance monitoring, only acid reflux events can be evaluated. PMID:22275050

Roman, S; Mion, F; Zerbib, F; Benamouzig, R; Letard, J C; Bruley des Varannes, S

2012-03-01

362

Dysregulated pH in Tumor Microenvironment Checkmates Cancer Therapy  

PubMed Central

Introduction: The dysregulation of pH by cancerous cells of solid tumors is able to create a unique milieu that is in favor of progression, invasion and metastasis as well as chemo-/immuno-resistance traits of solid tumors. Bioelements involved in pH dysregulation provide new set of oncotargets, inhibition of which may result in better clinical outcome. Methods: To study the impacts of pH dysregulation, we investigated the tumor development and progression in relation with Warburg effect, glycolysis and formation of aberrant tumor microenvironment. Results: The upregulation of glucose transporter GLUT-1 and several enzymes involve in glycolysis exacerbates this phenomenon. The accumulation of lactic acids in cancer cells provokes upregulation of several transport machineries (MCT-1, NHE-1, CA IX and H+ pump V-ATPase) resulting in reinforced efflux of proton into extracellular fluid. This deviant event makes pH to be settled at 7.4 and 6.6 respectively in cancer cells cytoplasm and extracellular fluid within the tumor microenvironment, which in return triggers secretion of lysosomal components (various enzymes in acidic milieu with pH 5) into cytoplasm. All these anomalous phenomena make tumor microenvironment (TME) to be exposed to cocktail of various enzymes with acidic pH, upon which extracellular matrix (ECM) can be remodeled and even deformed, resulting in emergence of a complex viscose TME with high interstitial fluid pressure. Conclusion: It seems that pH dysregulation is able to remodel various physiologic functions and make solid tumors to become much more invasive and metastatic. It also can cause undesired resistance to chemotherapy and immunotherapy. Hence, cancer therapy needs to be reinforced using specific inhibitors of bioelements involved in pH dysregulation of TME in solid tumors.

Barar, Jaleh; Omidi, Yadollah

2013-01-01

363

High-speed contouring enhanced with PH curves  

Microsoft Academic Search

In this paper, Pythagorean hodograph (P-H) curve theory is used for high-speed contouring applications. There are large contouring\\u000a errors around sharp corners when low-bandwidth servo controllers (such as P-PI control) are used. It is possible to construct\\u000a a P-H curve in the region of sharp corners in order to decrease the amount of cornering error. The developed algorithm is\\u000a implemented

Behnam Moetakef Imani; Javad Jahanpour

2008-01-01

364

Platinum, iridium and rhodium complexes with substituted bis -(diphenylphosphino)methane ligands Ph 2 PCH(R)PPh 2 (R = Me, Ph or SiMe 3 )  

Microsoft Academic Search

Substituted phosphines of the type Ph2PCH(R)PPh2 and their PtII complexes [PtX2{Ph2PCH(R)PPh2}] (R = Me, Ph or SiMe3; X = halide) were prepared. Treatment of [PtCl2(NCBut)2] with Ph2PCH(SiMe3)-PPh2 gave [PtCl2(Ph2PCH2PPh2)], while treatment with Ph2PCH(Ph)PPh2 gave [Pt{Ph2PCH(Ph)PPh2}2]Cl2. Reaction of p-MeC6H4C?CLi or PhC?CLi with [PtX2{Ph2PCH(Me)PPh2}] gave [Pt(C?CC6H4Me-p)2-{Ph2PCH(Me)PPh2}] (X = I) and [Pt{Ph2PC(Me)PPh2}2](X = Cl),while reaction of p-MeC6H4C?CLi with [Pt{Ph2PCH(Ph)PPh2}2]Cl2 gave [Pt{Ph2PC(Ph)PPh2}2]. The platinum

Lamaan J. Al-Hayaly

1998-01-01

365

Magnetic Optical Sensor Particles for pH Measurement  

NASA Astrophysics Data System (ADS)

Magnetic optical sensor particles (MOSePs) in nanometer scale for pH measurement were synthesized and characterized. The measurement of pH is based on a ratiometric evaluation of the fluorescence of a pH-sensitive indicator dye (N-fluorescein-acrylamide) and a reference dye (a rhodamine derivative) which is not affected by pH. Measurement of pH in aqueous media in the range of pH 5 to 9 is reversibly possible. As the particles can be collected in front of fiber optics with a specially designed separator, signal enhancement is easily achieved. Therefore, a low concentration of MOSePs is sufficient for investigations. Using the here reported MOSePs, the read out of pH is noninvasive, i.e., no dip probe needs to be inserted into the medium. In addition, no further preparation steps are required, pH-sensitive MOSePs can be simply pipetted into the medium prior to measurement, magnetically collected at the side and read out with a fiber optic device through the glass wall.

Scheucher, Elisabeth; Mistlberger, Günter; Klimant, Ingo

2010-12-01

366

Automated high precision secondary pH measurements  

NASA Astrophysics Data System (ADS)

A new setup for high precision, automated secondary pH measurements together with a reference measurement procedure has been developed and tested in interlaboratory comparisons using buffers pH 4.005, pH 7.000, and pH 10.012 at 25 °C and 37 °C. Using primary buffers as standards, a standard uncertainty in pH better than 0.005 can be reached. The central measuring device is a one piece, thermostatted cell of PFA (perfluoroalkoxy) with a built-in Hamilton® Single Pore™ Glass electrode. Due to its flow-through principle this device allows pH measurements with low consumption of measurement solutions. The very hydrophobic and smooth PFA as construction material facilitates complete emptying of the cell. Furthermore, the tempering unit affords very precise temperature control and hence contributes to the low target uncertainty of the produced secondary buffer solutions. Use of a symmetric measurement sequence and the two point calibration was sufficient to reach high precision and accuracy.

Bastkowski, F.; Jakobsen, P. T.; Stefan, F.; Kristensen, H. B.; Jensen, H. D.; Kawiecki, R.; Wied, C. E.; Kauert, A.; Seidl, B.; Spitzer, P.; Eberhardt, R.; Adel, B.

2013-04-01

367

Monitoring pH and ORP in a SHARON reactor.  

PubMed

This paper analyses the valuable information provided by the on-line measurements of pH and oxidation reduction potential (ORP) in a continuous single high ammonia removal over nitrite (SHARON) reactor. A laboratory-scale SHARON reactor equipped with pH, ORP, electric conductivity and dissolved oxygen (DO) probes has been operated for more than one year. Nitrogen removal over nitrite has been achieved by adding methanol at the beginning of anoxic stages. Time evolution of pH and ORP along each cycle allows identifying the decrease in nitritation rate when ammonia is consumed during the aerobic phase and the end of the denitrification process during the anoxic phase. Therefore, monitoring pH and ORP can be used to develop a real-time control system aimed at optimizing the length of both aerobic and anoxic stages. Real-time control of methanol addition can be carried out by using the information provided by these probes: excessive methanol addition in the anoxic stage is clearly detected in the ORP profile of the following aerobic phase, while a deficit of methanol is detected in both pH and ORP profiles of that anoxic phase. Moreover, other valuable information such as the amount of ammonia nitrified, failures in DO measurements, excessive stirring during the anoxic stage and methanol dosage in the aerobic phase was also provided by the pH and ORP profiles. PMID:22049741

Claros, J; Serralta, J; Seco, A; Ferrer, J; Aguado, D

2011-01-01

368

pH- and ionic-strength-induced structural changes in poly(acrylic acid)-lipid-based self-assembled materials.  

SciTech Connect

The effect of a polyanion introduced as a lipid conjugate (poly(acrylic acid)- dimyristoyl-sn-glycero-3-phosphoethanolamine, PAA-DMPE) on the structure of a self-assembled, biomembrane mimetic has been evaluated using synchrotron small-angle X-ray scattering (SAXS). At high grafting density (8-11 mol.%), the PAA chains were found to produce significant changes in structure in response to changes in pH and electrolyte composition. At low pH and in the absence of salt (NaCl), the neutral PAA chains adopt a coil conformational state that leads to the formation of a swollen lamellar structure. Upon the addition of salt at low to intermediate pH values, two lamellar phases, a collapsed and an expanded structure, coexist. Finally, when the polymer is fully ionized (at high pH), the extended conformation of the polymer generates a cubic phase. The results of this study contribute to an understanding of how polyelectrolytes may ultimately be harnessed for the preparation of self-assembling materials responsive to external stimuli.

Crisci, A.; Hay, D. N. T.; Seifert, S.; Firestone, M. A.

2009-01-01

369

Comparing Metal Leaching and Toxicity from High pH, Low pH, and High Ammonia Fly Ash  

SciTech Connect

Previous work with both class F and class C fly ash indicated minimal leaching from most fly ashes tested. However, the addition of NOx removal equipment might result in higher levels of ammonia in the fly ash. We have recently been testing fly ash with a wide range of pH (3.7-12.4) originating from systems with NOx removal equipment. Leaching experiments were done using dilute CaCl2 solutions in batch and columns and a batch nitric acid method. All methods indicated that the leaching of heavy metals was different in the highest ammonia sample tested and the high pH sample. However, toxicity testing with the Microtox system has indicated little potential toxicity in leachates except for the fly ash at the highest pH (12.4). When the leachate from the high pH fly ash was neutralized, toxicity was eliminated.

Palumbo, Anthony Vito [ORNL; Phillips, Jana Randolph [ORNL; Fagan, Lisa Anne [ORNL; Drake, Meghan M [ORNL; Ruther, Rose Emily [New College of Florida, Sarasota, FL; Fisher, L. Suzanne [Tennessee Valley Authority (TVA); Amonette, J. E. [Pacific Northwest National Laboratory (PNNL)

2007-01-01

370

Comparing metal leaching and toxicity from high pH, low pH, and high ammonia fly ash  

SciTech Connect

Previous work with both class F and class C fly ash indicated minimal leaching from most fly ashes tested. However, the addition of NOx removal equipment might result in higher levels of ammonia in the fly ash. We have recently been testing fly ash with a wide range of pH (3.7–12.4) originating from systems with NOx removal equipment. Leaching experiments were done using dilute CaCl2 solutions in batch and columns and a batch nitric acid method. All methods indicated that the leaching of heavy metals was different in the highest ammonia sample tested and the high pH sample. However, toxicity testing with the Microtox* system has indicated little potential toxicity in leachates except for the fly ash at the highest pH (12.4). When the leachate from the high pH fly ash was neutralized, toxicity was eliminated.

Palumbo, Anthony V.; Tarver, Jana R.; Fagan, Lisa A.; McNeilly, Meghan S.; Ruther, Rose; Fisher, L. S.; Amonette, James E.

2007-07-01

371

A first-principles study on the effect of biaxial strain on the ultimate performance of monolayer MoS2-based double gate field effect transistor  

NASA Astrophysics Data System (ADS)

In this work, the effect of biaxial strain on the electronic band structure of monolayers of MoS2 is investigated. The effective mass of carriers under different strain values is extracted and the achieved results are discussed. For the first time, we have assessed the effect of biaxial strain on the ultimate performance of MoS2-based double gate field effect transistors (DGFETs). The results indicate that by strain engineering, a significant performance improvement of MoS2-based DGFETs can be achieved.

Mohammad Tabatabaei, Seyed; Noei, Maziar; Khaliji, Kaveh; Pourfath, Mahdi; Fathipour, Morteza

2013-04-01

372

Secondary pH standards and their uncertainty in the context of the problem of two pH scales  

Microsoft Academic Search

Establishing a traceability route with all measurement and uncertainty relationships determined is an important aspect of traceability, and seems to be particularly striking in pH measurement. In this paper the issue of evaluation of secondary pH standards measured with reference to a primary standard in a differential cell with free diffusion type liquid junctions is considered. Relatively high uncertainty, U=0.015,

Rouvim Kadis

2002-01-01

373

Atomistic simulations of liquid crystal mixtures of alkoxy substituted phenylpyrimidines 2PhP and PhP14  

NASA Astrophysics Data System (ADS)

We study liquid crystal mixtures of alkoxy substituted phenylpyrimidines 2-[4-(butyloxy)phenyl]-5-(octyloxy)pyrimidine (2PhP) and 2-[4-(tetradecyloxy)phenyl]-5-(tetradecyloxy)pyrimidine (PhP14) using molecular dynamics simulations at the all atom level. The molecular length of PhP14 is 1.8 times that of 2PhP, resulting in an interesting binary mixture phase diagram. Our simulations are composed of 1000-1600 molecules for a total of 80 000-130 000 atomic sites, with total simulation times of 60-100 ns. We first show that a pure 2PhP system self-assembles into isotropic, nematic, smectic A and smectic C phases, and a pure PhP14 system self-assembles into isotropic and smectic C phases. Binary mixtures of PhP14 and 2PhP display a stabilization of the smectic A phase at the expense of the smectic C and nematic phases. We determine that the concentration-induced phase transition from the smectic C to the smectic A phase in the mixture is driven by an out-of-layer fluctuation arrangement of the molecules. We also observe that the tilt angle in the smectic C phases formed in the mixtures is concentration dependent. The results of our simulations are in good agreement with the experimental findings of Kapernaum et al. [J. Org. Chem. 5, 65 (2009)], thus showing that atomistic simulations are capable of reproducing the phase behavior of liquid crystal mixtures and can also provide microscopic details regarding the mechanisms that govern phase stability.

Yan, Fangyong; Earl, David J.

2012-03-01

374

Intracellular pH modulation of ADF/cofilin proteins.  

PubMed

The ADF/cofilin (AC) proteins are necessary for the high rates of actin filament turnover seen in vivo. Their regulation is complex enough to underlie the precision in filament dynamics needed by stimulated cells. Disassembly of actin by AC proteins is inhibited in vitro by phosphorylation of ser3 and pH<7.1. This study of Swiss 3T3 cells demonstrates that pH also affects AC behavior in vivo: (1) Wounded cells show pH-dependent AC translocation to alkaline-induced ruffling membrane; (2) The Triton extractable (soluble) ADF from Swiss 3T3 cells decreases from 42+/-4% to 23+/-4% when the intracellular pH (pH(i)) is reduced from 7.4 to 6.6; (3) Covariance and colocalization analyses of immunostained endogenous proteins show that ADF partitions more with monomeric actin and less with polymeric actin when pH(i) increases. However, the distribution of cofilin, a less pH-sensitive AC in vitro, does not change with pH; (4) Only the unphosphorylatable AC mutant (A3), when overexpressed as a GFP chimera, uniquely produces aberrant cellular phenotypes and only if the pH is shifted from 7.1 to 6.6 or 7.4. A mechanism is proposed that explains why AC(A3)-GFP and AC(wt)-GFP chimeras generate different phenotypes in response to pH changes. Phospho-AC levels increase with cell density, and in motile cells, phospho-AC increases with alkalization, suggesting a homeostatic mechanism that compensates for increased AC activity and filament turnover. These results show that the behavior of AC proteins with pH-sensitivity in vitro is affected by pH in vivo. PMID:11093252

Bernstein, B W; Painter, W B; Chen, H; Minamide, L S; Abe, H; Bamburg, J R

2000-12-01

375

Abnormal Vaginal pH and Mycoplasma genitalium infection  

PubMed Central

Study Objective Mycoplasma genitalium (MG) is a sexually transmitted pathogen linked to female morbidity, but testing for MG is not standardized. We aimed to determine which point-of-care (POC) vaginal tests could predict MG infection. Design, Setting, Participants A cross sectional study recruited sexually active adolescent women, aged 14–22 years (n=217) from an urban medical center. Interventions and Main Outcome Measures Vaginal swabs were POC tested for pH, amines, clue cells, sialidase and Trichomonas vaginalis (TV). MG was detected by research-use-only transcription mediated amplification (TMA) assay. Presence of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) were confirmed using TMA. Three criteria were required for diagnosis of Clinical BV: pH >4.5, presence of amines, and > 20% clue cells. Associations were assessed using logistic regression (LR). Results TMA detected MG in 30 (14%), CT in 49 (23%), and NG in 21 (10%) of the samples tested. POC vaginal tests were positive for TV in 21%, amines in 52%, clue cells in 33%, sialidase in 22%, pH > 4.5 in 56%, and clinical BV in 19% of the samples tested. Using logistic regression, pH > 4.5 was a predictor of MG (odds ratio 4.4, p<.05). Of 131 women without clinical BV or TV, 25% of those with pH>4.5 had MG, compared to 9% of those with pH?4.5 (p=.02). Conclusions Until standardized, approved testing for MG is available, pH may be a useful indicator to suspect MG, especially in the absence of BV and TV.

Huppert, Jill S.; Bates, Justin R.; Weber, Akilah F.; Quinn, Nicole; Gaydos, Charlotte A.

2012-01-01

376

DIGESTION PRODUCTS OF THE PH20 HYALURONIDASE INHIBIT REMYELINATION  

PubMed Central

OBJECTIVE Oligodendrocyte progenitor cells (OPCs) recruited to demyelinating lesions often fail to mature into oligodendrocytes (OLs) that remyelinate spared axons. The glycosaminoglycan hyaluronan (HA) accumulates in demyelinating lesions and has been implicated in the failure of OPC maturation and remyelination. We tested the hypothesis that OPCs in demyelinating lesions express a specific hyaluronidase, and that digestion products of this enzyme inhibit OPC maturation. METHODS Mouse OPCs grown in vitro were analyzed for hyaluronidase expression and activity. Gain of function studies were used to define the hyaluronidases that blocked OPC maturation. Mouse and human demyelinating lesions were assessed for hyaluronidase expression. Digestion products from different hyaluronidases and a hyaluronidase inhibitor were tested for their effects on OPC maturation and functional remyelination in vivo. RESULTS OPCs demonstrated hyaluronidase activity in vitro and expressed multiple hyaluronidases including HYAL1, HYAL2, and PH20. HA digestion by PH20 but not other hyaluronidases inhibited OPC maturation into OLs. In contrast, inhibiting HA synthesis did not influence OPC maturation. PH20 expression was elevated in OPCs and reactive astrocytes in both rodent and human demyelinating lesions. HA-digestion products generated by the PH20 hyaluronidase but not another hyaluronidase inhibited remyelination following lysolecithin-induced demyelination. Inhibition of hyaluronidase activity lead to increased OPC maturation and promoted increased conduction velocities through lesions. INTERPRETATION We determined that PH20 is elevated in demyelinating lesions and that increased PH20 expression is sufficient to inhibit OPC maturation and remyelination. Pharmacological inhibition of PH20 may therefore be an effective way to promote remyelination in multiple sclerosis and related conditions.

Preston, Marnie; Gong, Xi; Su, Weiping; Matsumoto, Steven G.; Banine, Fatima; Winkler, Clayton; Foster, Scott; Xing, Rubing; Struve, Jaime; Dean, Justin; Baggenstoss, Bruce; Weigel, Paul H.; Montine, Thomas J.; Back, Stephen A.; Sherman, Larry S.

2012-01-01

377

Optical measurement method for determining the pH of a medium using ageladine A as a fluorescent pH indicator  

US Patent & Trademark Office Database

An optical measurement method for determining a pH of a medium includes adding a fluorescent pH indicator to the medium. The pH indicator is based on naturally-obtained or synthesized ageladine A. The pH indicator is irradiated with light of at least one wavelength so as to provide fluorescence excitation of the pH indicator. An emitted fluorescence intensity of the pH indicator is detected as a measure for the pH of the medium.

2012-06-12

378

Intracellular pH and the Control of Multidrug Resistance  

NASA Astrophysics Data System (ADS)

Many anticancer drugs are classified as either weak bases or molecules whose binding to cellular structures is pH dependent. Accumulation of these drugs within tumor cells should be affected by transmembrane pH gradients. Indeed, development of multidrug resistance (MDR) in tumor cells has been correlated with an alkaline shift of cytosolic pH. To examine the role of pH in drug partitioning, the distribution of two drugs, doxorubicin and daunomycin, was monitored in fibroblasts and myeloma cells. In both cell types the drugs rapidly accumulated within the cells. The highest concentrations were measured in the most acidic compartments-e.g., lysosomes. Modifying the cellular pH in drug-sensitive cells to mimic reported shifts in MDR caused an immediate change in the cellular drug concentration. Drug accumulation was enhanced by acidic shifts and reversed by alkaline shifts. All of these effects were rapid and reversible. These results demonstrate that the alkaline shift observed in MDR is sufficient to prevent the accumulation of chemotherapeutic drugs independent of active drug efflux.

Simon, Sanford; Roy, Deborshi; Schindler, Melvin

1994-02-01

379

Near-infrared noninvasive spectroscopic determination of pH  

DOEpatents

Methods and apparatus for, preferably, determining noninvasively and in vitro pH in a human. The non-invasive method includes the steps of: generating light at three or more different wavelengths in the range of 1000 nm to 2500 nm; irradiating blood containing tissue; measuring the intensities of the wavelengths emerging from the blood containing tissue to obtain a set of at least three spectral intensities v. wavelengths; and determining the unknown values of pH. The determination of pH is made by using measured intensities at wavelengths that exhibit change in absorbance due to histidine titration. Histidine absorbance changes are due to titration by hydrogen ions. The determination of the unknown pH values is performed by at least one multivariate algorithm using two or more variables and at least one calibration model. The determined pH values are within the physiological ranges observed in blood containing tissue. The apparatus includes a tissue positioning device, a source, at least one detector, electronics, a microprocessor, memory, and apparatus for indicating the determined values.

Alam, Mary K. (P.O. Box 1083, Cedar Crest, NM 87008); Robinson, Mark R. (1415 Calle del Ranchero NE, Albuquerque, NM 87106)

1998-08-11

380

The Production Rate and Employment of Ph.D. Astronomers  

NASA Astrophysics Data System (ADS)

In an effort to encourage self-regulation of the astronomy job market, I examine the supply of, and demand for, astronomers over time. On the supply side, I document the production rate of Ph.D. astronomers from 1970 to 2006 using the UMI Dissertation Abstracts database, along with data from other independent sources. I compare the long-term trends in Ph.D. production with federal astronomy research funding over the same time period, and I demonstrate that additional funding is correlated with higher subsequent Ph.D. production. On the demand side, I monitor the changing patterns of employment using statistics about the number and types of jobs advertised in the AAS Job Register from 1984 to 2006. Finally, I assess the sustainability of the job market by normalizing this demand by the annual Ph.D. production. The most recent data suggest that there are now annual advertisements for about one postdoctoral job, half a faculty job, and half a research/support position for every new domestic Ph.D. recipient in astronomy and astrophysics. The average new astronomer might expect to hold up to 3 jobs before finding a steady position.

Metcalfe, Travis S.

2008-02-01

381

The role of ph fronts in tissue electroporation based treatments.  

PubMed

Treatments based on electroporation (EP) induce the formation of pores in cell membranes due to the application of pulsed electric fields. We present experimental evidence of the existence of pH fronts emerging from both electrodes during treatments based on tissue EP, for conditions found in many studies, and that these fronts are immediate and substantial. pH fronts are indirectly measured through the evanescence time (ET), defined as the time required for the tissue buffer to neutralize them. The ET was measured through a pH indicator imaged at a series of time intervals using a four-cluster hard fuzzy-c-means algorithm to segment pixels corresponding to the pH indicator at every frame. The ET was calculated as the time during which the number of pixels was 10% of those in the initial frame. While in EP-based treatments such as reversible (ECT) and irreversible electroporation (IRE) the ET is very short (though enough to cause minor injuries) due to electric pulse characteristics and biological buffers present in the tissue, in gene electrotransfer (GET), ET is much longer, enough to denaturate plasmids and produce cell damage. When any of the electric pulse parameters is doubled or tripled the ET grows and, remarkably, when any of the pulse parameters in GET is halved, the ET drops significantly. Reducing pH fronts has relevant implications for GET treatment efficiency, due to a substantial reduction of plasmid damage and cell loss. PMID:24278257

Maglietti, Felipe; Michinski, Sebastian; Olaiz, Nahuel; Castro, Marcelo; Suárez, Cecilia; Marshall, Guillermo

2013-01-01

382

The conundrum of pH in water nanodroplets: sensing pH in reverse micelle water pools.  

PubMed

In aqueous environments, acidity is arguably the most important property dictating the chemical, physical, and biological processes that can occur. However, in a variety of environments where the minuscule size limits the number of water molecules, the conventional macroscopic description of pH is no longer valid. This situation arises for any and all nanoscopically confined water including cavities in minerals, porous solids, zeolites, atmospheric aerosols, enzyme active sites, membrane channels, and biological cells and organelles. To understand pH in these confined spaces, we have explored reverse micelles as a model system that confines water to nanoscale droplets. At the appropriate concentrations, reverse micelles form in ternary or higher order solutions of nonpolar solvent, polar solvent (usually water), and amphipathic molecules, usually surfactants or lipids. Measuring the acidity, or local density of protons, commonly known as pH, of these nanoscopic water pools in reverse micelles is challenging. First, because the volume of the water in these reverse micelles is so minute, we cannot probe its proton concentration using traditional pH meters. Second, the traditional concept of pH breaks down in a nanosystem that includes fewer than 10(7) water molecules. Third, the interpretation of results from studies attempting to measure acidity or pH in these environments is nontrivial because the conditions fall outside the accepted IUPAC definition for pH. Researchers have developed experimental methods to measure acidity indirectly using various spectroscopic probe molecules. Most measurements of intramicellar pH have employed optical spectroscopy of organic probe molecules containing at least one labile proton coupled to electronic transitions to track pH changes in the environment. These indirect measurements of the pH reflect the local environment sensed by the probe and are complicated by the probe location within the sample and how that location affects properties such as pK(a). Thus, interpretation of the measurement in the highly heterogeneous reverse micellar environment can be challenging. Organic pH probes can often produce ambiguous acidity measurements, because the probes can readily associate with or penetrate the micellar interface. Protonation can also dramatically change the polarity of the probe and shift the probe's location within the system. As a result, researchers have developed highly charged pH-sensitive probes such as hydroxypyrene trisulfonate, vanadate or phosphate that reside in the water pool both before and after protonation. For inorganic probes researchers have used multinuclear NMR spectroscopy to directly measure conditions in the water droplet. Regardless of the probe and method employed, reverse micellar studies include many implicit assumptions. All reported pH measurements comprise averages of molecular ensembles rather than the response of a single molecule. Experiments also represent averages of the dynamic reverse micelles over the time of the experiments. Thus the experiments report results from an average molecular position, pK(a), ionic strength, viscosity, etc. Although the exact meaning of pH in nanosized waterpools challenges scientific intuition and experimental data are non-trivial to interpret, continued experimental studies are critical to improve understanding of these nanoscopic water pools. Experimental data will allow theorists the tools to develop the models that further explore the meaning of pH in nanosized environments. PMID:22812536

Crans, Debbie C; Levinger, Nancy E

2012-10-16

383

Chondrocytes, synoviocytes and dermal fibroblasts all express PH-20, a hyaluronidase active at neutral pH  

PubMed Central

Hyaluronan (HA), an important component of connective tissues, is highly metabolically active, but the mechanisms involved in its catabolism are still largely unknown. We hypothesized that a protein similar to sperm PH-20, the only mammalian hyaluronidase known to be active at neutral pH, could be expressed in connective tissue cells. An mRNA transcript similar to that of PH-20 was found in chondrocytes, synoviocytes, and dermal fibroblasts, and its levels were enhanced upon stimulation with IL-1. In cell layers extracted with Triton X-100 – but not with octylglucoside – and in culture media, a polyclonal antipeptide anti-PH-20 antibody identified protein bands with a molecular weight similar to that of sperm PH-20 (60 to 65 kDa) and exhibiting a hyaluronidase activity at neutral pH. Further, upon stimulation with IL-1, the amounts of the neutral-active hyaluronidase increased in both cell layers and culture media. These findings contribute potential important new insights into the biology of connective tissues. It is likely that PH-20 facilitates cell-receptor-mediated uptake of HA, while overexpression or uncontrolled expression of the enzyme can cause great havoc to connective tissues: not only does HA fragmentation compromise the structural integrity of tissues, but also the HA fragments generated are highly angiogenic and are potent inducers of proinflammatory cytokines. On the other hand, the enzyme activity may account for the progressive depletion of HA seen in osteoarthritis cartilage, a depletion that is believed to play an important role in the apparent irreversibility of this disease process.

El Hajjaji, Hafida; Cole, Ada Asbury; Manicourt, Daniel-Henri

2005-01-01

384

Chondrocytes, synoviocytes and dermal fibroblasts all express PH-20, a hyaluronidase active at neutral pH.  

PubMed

Hyaluronan (HA), an important component of connective tissues, is highly metabolically active, but the mechanisms involved in its catabolism are still largely unknown. We hypothesized that a protein similar to sperm PH-20, the only mammalian hyaluronidase known to be active at neutral pH, could be expressed in connective tissue cells. An mRNA transcript similar to that of PH-20 was found in chondrocytes, synoviocytes, and dermal fibroblasts, and its levels were enhanced upon stimulation with IL-1. In cell layers extracted with Triton X-100 - but not with octylglucoside - and in culture media, a polyclonal antipeptide anti-PH-20 antibody identified protein bands with a molecular weight similar to that of sperm PH-20 (60 to 65 kDa) and exhibiting a hyaluronidase activity at neutral pH. Further, upon stimulation with IL-1, the amounts of the neutral-active hyaluronidase increased in both cell layers and culture media. These findings contribute potential important new insights into the biology of connective tissues. It is likely that PH-20 facilitates cell-receptor-mediated uptake of HA, while overexpression or uncontrolled expression of the enzyme can cause great havoc to connective tissues: not only does HA fragmentation compromise the structural integrity of tissues, but also the HA fragments generated are highly angiogenic and are potent inducers of proinflammatory cytokines. On the other hand, the enzyme activity may account for the progressive depletion of HA seen in osteoarthritis cartilage, a depletion that is believed to play an important role in the apparent irreversibility of this disease process. PMID:15987477

El Hajjaji, Hafida; Cole, Ada Asbury; Manicourt, Daniel-Henri

2005-01-01

385

Ruthenium(II) chemistry of phosphorus-based ligands, Ph 2PN(R)PPh 2 (R=Me or Ph) and Ph 2PN(Ph)P(E) Ph 2 (E=S or Se). Solution thermochemical study of ligand substitution reactions in the Cp?RuCl(COD) (Cp?=Cp, Cp*; COD=cyclooctadiene) system  

Microsoft Academic Search

The enthalpies of reactions of Cp?RuCl(COD) (Cp?=Cp, Cp*; COD=cyclooctadiene) with bis(phosphino)amines of the type Ph2PN(R)PPh2(R=Me 1 or R=Ph 2) and the monochalcogen derivatives Ph2PN(Ph)P(E)Ph2(E=S 3 or Se 4) leading to the formation of Cp?RuCl(PNP) and Cp?RuCl{PNP(E)} complexes, respectively, have been measured by anaerobic solution calorimetry in THF at 30°C. These reactions are clean and quantitative. The synthesis and characterization of

Rashmishree Panda; Dale C. Smith Jr; Amy Klaman

2000-01-01

386

Nanocrystalline hydroxyapatite prepared under various pH conditions.  

PubMed

Hydroxyapatite (HAP) has sovereign biomedical application due to its excellent biocompatibility, chemical and crystallographic similitude with natural human bone. In this present work, we discussed about the role of pH in the synthesis of calcium phosphate compound using calcium nitrate tetrahydrate and di-ammonium hydrogen phosphate as starting materials by chemical precipitation method assisted with ultrasonic irradiation technique. 5% polyethylene glycol (PEG600) is added along with the precursors under various pH condition of 7, 9 and 11 respectively. The functional group analysis, crystallized size and fraction of crystallized size are confirmed using Fourier Transformation Infra-Red spectroscopy and X-ray diffraction pattern. Morphological observations are done by scanning electron microscope. The results revealed the presence of nanocrystalline hydroxyapatite at pH above 9. PMID:24820320

Palanivelu, R; Mary Saral, A; Ruban Kumar, A

2014-10-15

387

Memristive sensors for pH measure in dry conditions  

NASA Astrophysics Data System (ADS)

A large progress in pH sensing with nanowire based ion-sensitive field-effect transistors (ISFETs) has been demonstrated over the years. The electrochemical reactions occurring at the wire surface-to-electrolyte interface play a key role in the detection of ions. In this letter, we show that pH sensing can also be performed on dried samples, through electrical measurements in air with a new kind of memristive sensor. The detection of different concentrations of [H+] is confirmed by both the increased conductance and hysteretic voltage gap of the wires. The observed change in the electrical properties with pH in dry conditions is related to the formation of a wet film at the nanowire surface. Ions from the initial solution are free to move in the final water thin film at the sensing interface with consequent polarization of the NW surface.

Puppo, Francesca; Di Ventra, Massimiliano; De Micheli, Giovanni; Carrara, Sandro

2014-06-01

388

PhET Teacher Activities: Experimental Design with Forces  

NSDL National Science Digital Library

This middle school lesson plan blends a classroom experiment with the interactive PhET simulation Masses and Springs. Students design and conduct an experiment to test their predictions about the behavior of springs with masses attached. The simulation is used to explore kinetic and potential energy of spring motion and to visualize how the spring moves on different planets with varied gravitational constants. The lesson provides extensive background information for both educators and learners, scripted teacher discussion, student guides, and assessment materials with answer keys. The "Masses & Springs" simulation (which is required to complete this activity) is available from PhET at: Masses & Springs. This lesson is part of the PhET (Physics Education Technology Project), a large collection of free interactive science simulations.

Texas, Uteach -.

2012-09-24

389

PhET Teacher Activities: Nuclear Fission Simulation - Student Guide  

NSDL National Science Digital Library

This student hand-out was created specifically to accompany the PhET simulation "Nuclear Fission". It provides guided directions on using the simulation to ensure that students stay focused on learning goals. The simulation features a neutron gun that "fires" an accelerated neutron into a Uranium-235 nucleus. By using this printed guide, students will be prompted to think about what happens in a nuclear reaction, what makes a nucleus "fissionable" and how nuclear power containment vessels prevent a runaway chain reaction. The fission simulation, which must be open and displayed to complete this activity, is available from PhET at: Nuclear Fission. This lesson is part of PhET (Physics Education Technology Project), a large collection of free interactive simulations for science education.

Blaisdell, Mark

390

PhET Teacher Ideas: The Greenhouse Effect Lab  

NSDL National Science Digital Library

This page features an inquiry-based lab, created by a high school teacher for use with the PhET simulation Greenhouse Effect. The author gives explicit instructions for using the simulation to conduct an experiment. The experimental question: "Which atmospheric gas -- methane, water, carbon dioxide, oxygen, or nitrogen -- is the best absorber of infrared photons?" Students will be using the "Photon Absorption" section of the simulation, in which they shoot infrared and visible photons from a virtual emission gun. They can change and adjust levels of each gas to build their own atmospheric conditions. A comprehensive rubric is included. The related simulation, which is required to complete this activity, is available from PhET at: Greenhouse Effect Simulation. This item is part of a growing collection of simulations by the Physics Education Technology Project (PhET). Simulations were designed using principles from physics education research and refined based on student interviews and classroom observations.

Van Houten, Greg

391

PH and Electrochemical Responsive Materials for Corrosion Smart Coating Applications  

NASA Technical Reports Server (NTRS)

Corrosion is a costly issue for military operations and civil industries. While most corrosion initiates from localized corrosion form, such as pitting, failure directly caused by localized corrosion is the most dangerous kind, because it is difficult to anticipate and prevent, occurs very suddenly and can be catastrophic. One way of preventing these failures is with a coating that can detect and heal localized corrosion. pH and other electrochemical changes are often associated with localized corrosion, so it is expected that materials that are pH or otherwise electrochemical responsive can be used to detect and control corrosion. This paper will review various pH and electrochemical responsive materials and their potential applications in corrosion smart coatings. Current research results in this field will also be reported.

Li, Wenyan; Calle, Luz M.

2008-01-01

392

Nanocrystalline hydroxyapatite prepared under various pH conditions  

NASA Astrophysics Data System (ADS)

Hydroxyapatite (HAP) has sovereign biomedical application due to its excellent biocompatibility, chemical and crystallographic similitude with natural human bone. In this present work, we discussed about the role of pH in the synthesis of calcium phosphate compound using calcium nitrate tetrahydrate and di-ammonium hydrogen phosphate as starting materials by chemical precipitation method assisted with ultrasonic irradiation technique. 5% polyethylene glycol (PEG600) is added along with the precursors under various pH condition of 7, 9 and 11 respectively. The functional group analysis, crystallized size and fraction of crystallized size are confirmed using Fourier Transformation Infra-Red spectroscopy and X-ray diffraction pattern. Morphological observations are done by scanning electron microscope. The results revealed the presence of nanocrystalline hydroxyapatite at pH above 9.

Palanivelu, R.; Mary Saral, A.; Ruban Kumar, A.

2014-10-01

393

Chloride Concentration and pH Along the Endosomal Pathway  

NSDL National Science Digital Library

This animation depicts three membrane trafficking routes in a mammalian neurosecretory cell, highlighting the changing Cl– concentrations and pH values of the various endosomal subcompartments. The focus is on the endocytotic pathway and the different paths taken by clathrin-coated vesicles: the pathway for receptor recycling to the plasma membrane, the lysosomal pathway, or the pathway for synaptic vesicle recycling (in neurons). Each compartment shown has a distinctive pH and [Cl–], with values for pH indicated in blue and values for Cl– indicated in orange. This animation will be useful for teaching cell biology and highlighting both the dynamic nature of vesicular traffic and the changes in ionic balance associated with different cellular compartments.

Victor Faundez (Emory University School of Medicine;Department of Cell Biology REV); H. Criss Hartzell (Emory University School of Medicine;Department of Cell Biology REV); Elizabeth M. Adler (American Association for the Advancement of Science;Science's STKE)

2004-05-25

394

PPAR?, the ultimate thrifty gene  

Microsoft Academic Search

\\u000a \\u000a Abstract\\u000a \\u000a    The peroxisome proliferator-activated receptor gamma (PPAR?) quickly evolved over the last decade from a new orphan receptor to one of the best characterized nuclear receptors. This\\u000a fast pace in PPAR? research was triggered by two main discoveries. Firstly, that PPAR? was shown to have a key role in adipogenesis and be a master controller of the “thrifty gene

J. Auwerx

1999-01-01

395

SUPER ESP: Ultimate Electrostatic Precipitation.  

National Technical Information Service (NTIS)

The paper discusses SUPER ESP, a new electrostatic precipitator (ESP) concept, enabling high collection efficiencies with considerably smaller collection areas than has previously been possible. The new concept allows a major reduction in ESP size by usin...

N. Plaks

1991-01-01

396

The Ultimate Utility of Nonutility  

ERIC Educational Resources Information Center

While every sector of American life has been affected by the difficult financial times, higher education is experiencing a profound crisis that threatens the very foundations of education and the meaning of intellectual endeavor. The impact of the financial downturn has been both economic--in the form of lower enrollments, rising tuition, and…

Colletta, Lisa

2010-01-01

397

The Physics Professor's Ultimate Resources  

NSDL National Science Digital Library

Created by the CollegeOnline organization, this website corrals a number of websites together from institutions like the University of California - Irvine, the University of Kentucky, and the University of Utah. First-time visitors can scan through seven different subsections, such as "Geometry/Trigonometry", "Tools", and "Optics". A good place to start is with the "Virtual Labs", as they offer a melange of websites from physics labs around the country, complete with research summaries, interactive web activities, and so on. Moving on, the "Optics" area provides a fine explanation of visual illusions, Newton's color wheel, and a place where visitors can build their own rainbow. Finally, the site is rounded out by a nice "Miscellaneous" section that offers sine wave demonstrations, lunar phase illustrations, and a space time lab game.

398

Effect of pH on Porphyromonas gingivalis endotoxin affinity for resins.  

PubMed

This study evaluated the effect of pH on Porphyromonas gingivalis lipopolysaccharide (LPS) affinity for polymethyl methacrylate, polyethyl methacrylate, and polyethyl and polyisobutyl methacrylate resins. Specimens were exposed to 1,010 endotoxin units LPS in potassium phosphate buffer at pH 6, pH 7, or pH 8. Control specimens were incubated in LPS-free water. Sequence I evaluated LPS uptake and release from resin when exposure and elution pH were identical, whereas Sequence II evaluated LPS release from resin when elution pH differed from exposure pH. A slightly acidic pH decreased LPS affinity for all resins compared to pH 7. A slightly alkaline pH increased LPS affinity for the polyethyl methacrylate resin but decreased LPS affinity for the others compared to pH 7. The pH may affect resin-LPS affinity by altering LPS molecular charge. PMID:8957858

Knoernschild, K L; Tompkins, G R; Lefebvre, C A; Griffiths, L L; Schuster, G S

1996-01-01

399

pH sensing and regulation in cancer.  

PubMed

Cells maintain intracellular pH (pHi) within a narrow range (7.1-7.2) by controlling membrane proton pumps and transporters whose activity is set by intra-cytoplasmic pH sensors. These sensors have the ability to recognize and induce cellular responses to maintain the pHi, often at the expense of acidifying the extracellular pH. In turn, extracellular acidification impacts cells via specific acid-sensing ion channels (ASICs) and proton-sensing G-protein coupled receptors (GPCRs). In this review, we will discuss some of the major players in proton sensing at the plasma membrane and their downstream consequences in cancer cells and how these pH-mediated changes affect processes such as migration and metastasis. The complex mechanisms by which they transduce acid pH signals to the cytoplasm and nucleus are not well understood. However, there is evidence that expression of proton-sensing GPCRs such as GPR4, TDAG8, and OGR1 can regulate aspects of tumorigenesis and invasion, including cofilin and talin regulated actin (de-)polymerization. Major mechanisms for maintenance of pHi homeostasis include monocarboxylate, bicarbonate, and proton transporters. Notably, there is little evidence suggesting a link between their activities and those of the extracellular H(+)-sensors, suggesting a mechanistic disconnect between intra- and extracellular pH. Understanding the mechanisms of pH sensing and regulation may lead to novel and informed therapeutic strategies that can target acidosis, a common physical hallmark of solid tumors. PMID:24381558

Damaghi, Mehdi; Wojtkowiak, Jonathan W; Gillies, Robert J

2013-01-01

400

Critical issues in PhD training for biomedical scientists.  

PubMed

The rapidly changing world of modern biomedical research is raising important new issues for traditional PhD training programs and is creating concern among young PhD scientists about their futures. Specifically, the United States is producing substantially more biomedical PhDs than can be accommodated in professional positions that truly require the PhD as a credential. The "surplus" PhD population is being relegated to poorly paid, unstable, and increasingly unsatisfying jobs. In addition, many current graduate and postdoctoral training programs may not be adequately preparing young scientists for the more complex, more quantitative biological science of the future. Finally, many current graduate training programs are not attracting a sufficient portion of the most talented young people in the nation. To ameliorate these problems in the training and early career paths of basic biomedical scientists, the authors make specific recommendations, such as urging (1) that graduate trainees should be supported exclusively by competitive individual fellowships, training grants, or institutional funds and not by RO1s or similar research awards; (2) that graduate and postdoctoral stipends be increased so that they provide a reasonable living wage; and (3) that research-intensive academic institutions create a career path for biomedical PhDs other than that designed for the traditional tenure-track, grant-funded principal investigator and faculty member. They conclude that it is in the interest of faculty and institutions to make these and other drastic changes because the current system is both inherently unfair and self-destructive. PMID:11597839

Juliano, R L; Oxford, G S

2001-10-01

401

pH sensitive quantum dot-anthraquinone nanoconjugates.  

PubMed

Semiconductor quantum dots (QDs) have been shown to be highly sensitive to electron or charge transfer processes, which may alter their optical properties. This feature can be exploited for different sensing applications. Here, we demonstrate that QD-anthraquinone conjugates can function as electron transfer-based pH nanosensors. The attachment of the anthraquinones on the surface of QDs results in the reduction of electron hole recombination, and therefore a quenching of the photoluminescence intensity. For some anthraquinone derivatives tested, the quenching mechanism is simply caused by an electron transfer process from QDs to the anthraquinone, functioning as an electron acceptor. For others, electron transfer and energy transfer (FRET) processes were found. A detailed analysis of the quenching processes for CdSe/ZnS QD of two different sizes is presented. The photoluminescence quenching phenomenon of QDs is consistent with the pH sensitive anthraquinone redox chemistry. The resultant family of pH nanosensors shows pKa ranging ?5-8, being ideal for applications of pH determination in physiological samples like blood or serum, for intracellular pH determination, and for more acidic cellular compartments such as endosomes and lysosomes. The nanosensors showed high selectivity towards many metal cations, including the most physiologically important cations which exist at high concentration in living cells. The reversibility of the proposed systems was also demonstrated. The nanosensors were applied in the determination of pH in samples mimicking the intracellular environment. Finally, the possibility of incorporating a reference QD to achieve quantitative ratiometric measurements was investigated. PMID:24762336

Ruedas-Rama, Maria Jose; Hall, Elizabeth A H

2014-05-16

402

pH sensitive quantum dot–anthraquinone nanoconjugates  

NASA Astrophysics Data System (ADS)

Semiconductor quantum dots (QDs) have been shown to be highly sensitive to electron or charge transfer processes, which may alter their optical properties. This feature can be exploited for different sensing applications. Here, we demonstrate that QD-anthraquinone conjugates can function as electron transfer-based pH nanosensors. The attachment of the anthraquinones on the surface of QDs results in the reduction of electron hole recombination, and therefore a quenching of the photoluminescence intensity. For some anthraquinone derivatives tested, the quenching mechanism is simply caused by an electron transfer process from QDs to the anthraquinone, functioning as an electron acceptor. For others, electron transfer and energy transfer (FRET) processes were found. A detailed analysis of the quenching processes for CdSe/ZnS QD of two different sizes is presented. The photoluminescence quenching phenomenon of QDs is consistent with the pH sensitive anthraquinone redox chemistry. The resultant family of pH nanosensors shows pKa ranging ?5–8, being ideal for applications of pH determination in physiological samples like blood or serum, for intracellular pH determination, and for more acidic cellular compartments such as endosomes and lysosomes. The nanosensors showed high selectivity towards many metal cations, including the most physiologically important cations which exist at high concentration in living cells. The reversibility of the proposed systems was also demonstrated. The nanosensors were applied in the determination of pH in samples mimicking the intracellular environment. Finally, the possibility of incorporating a reference QD to achieve quantitative ratiometric measurements was investigated.

Ruedas-Rama, Maria Jose; Hall, Elizabeth A. H.

2014-05-01

403

Harvard College Observatory: Shapley's Factory for PhD Degrees?  

NASA Astrophysics Data System (ADS)

When Harlow Shapley assumed the Directorship of Harvard College Observatory in 1921, there was no program in place there to train the next generation of astronomers. In 1923, using the Pickering Fund for women assistants, Shapley hired a young English woman, Cecilia Payne, to work on stellar spectra. Just two short years later, Payne completed her research and wrote a celebrated thesis on stellar atmospheres. Because Harvard University was not prepared to confer a PhD degree on a woman at that time, Payne presented her thesis to Radcliffe College. Thus, in 1925 she became the first person to receive a PhD in astronomy for a research project at HCO. By 1933, a PhD in Astronomy had been conferred on eight graduate students who had undertaken research projects at HCO: four men who received their degree from Harvard, and four women, from Radcliffe. In subsequent years, however, the equal distribution of degrees for men and women quickly changed. When the 30th degree was bestowed in 1943, only 10 of the candidates were women. By 1955, when the 60th degree was conferred, only 14 women had received a PhD. In just two decades, then, the ratio of women astronomers had steadily dropped from a solid 50% at the height of the Shapley era to slightly less than 25% at his retirement. Also, until the mid-1960s, the women astronomers still had to apply to Radcliffe for their PhD degrees. This paper will briefly examine the funding and research topics of some of the HCO PhD candidates in the Shapley Era (1921-1955). It will also highlight some of their subsequent contributions to 20th-century American Astronomy.

Welther, B. L.

2000-12-01

404

Manganese toxicity to fungi: influence of pH  

SciTech Connect

The effects of Mn on mycelial proliferation of fungi and the effect of pH on Mn toxicity were evaluated. Results indicated that the fungi exhibited wide differences in their sensitivities to Mn. Incipient inhibition (i.e., the level of Mn at which growth inhibition was noted initially, P < 0.05) for Scopulariopsis brevicaulis and Aspergillus giganteus occurred at 100 ppM Mn; for Rhizopus stolonifer, Arthrobotrys conoides, Aspergillus niger, Aspergillus flavus, Trichoderma viride, and Penicillium vermiculatum at 500 ppM Mn; for Cephalosporium sp. at 1000 ppM Mn; and for Gliocladium sp. at 1000 to 1500 ppM Mn; growth of Aspergillus clavatus was not inhibited even at 2000 ppM Mn. No growth of S. brevicaulis occurred at 500 ppM Mn and of R. stolonifer at 1500 ppM Mn. The levels of Mn causing incipient and/or total inhibition of mycelial growth of the fungi studied were comparable to the levels reported to inhibit mycelial proliferation of some phylloplane fungi. Only A. conoides showed significant (P < 0.5) stimulation of mycelial growth by Mn; 10, 50, and 100 ppM Mn increased growth rates over control (0 ppM Mn) values. There was no consistent trend in the effect of pH on Mn toxicity to the fungi. However, each fungus showed a definitive response to Mn at the different pH levels. Thus, increasing the pH from 5.5 to 8.5 did not significantly affect the toxicity of Mn to Gliocladium sp., P. vermiculatum, or A. niger. The toxicity of Mn to R. stolonifer and T. viride was not different at pH 5.5 and 6.5, but increasing the pH to 7.5 or 8.5 significantly enhanced the toxicity.

Babich, H.; Stotzky, G.

1981-10-01

405

PhET Teacher Activities: Vectors Simulations Lab  

NSDL National Science Digital Library

This virtual lab was developed by a high school teacher specifically for use with the PhET simulation "Motion in 2D". It provides explicit direction for using the simulation to explore vector quantities, vector addition, and calculating resultants. In the last half of the activity, students demonstrate understanding by performing specific calculations, then using the simulation to check their work. The lesson includes printable student data tables. The associated simulation (which must be running to complete this activity) is available from PhET at: Motion in 2D.

Bires, Chris

2013-02-05

406

Water Quality and pH Levels in Aquatic Ecosystems  

NSDL National Science Digital Library

In this fun and in depth hands-on experiment, learners test various liquid samples (distilled water, lemon juice, vinegar, and baking soda mixed with water) to determine their pH levels and identify each sample as either acid, base or neutral chemical. Then, over the course of several weeks, learners perform a number of tests and observe the affects of pH level on plants. The wrap up section of this activity discusses acid rain and its dramatic impact on aquatic animals, and tips for going further.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

407

Measurement and control of pH in hydrothermal solutions  

SciTech Connect

Hydrogen-electrode concentration cells with liquid junction are routinely used to measure the pH of aqueous solutions from 0 to 300 C. Results include the dissociation constants of common acids and bases and the hydrolysis and complexation of metal ions in aqueous electrolytes over a wide range of salinities. Recently, we have utilized these cells to examine the sorption of H{sup +} on mineral surfaces, the solubility of minerals with continuous in situ pH measurement, and the thermal decompositon rates of organic acids.

Wesolowski, D.J.; Palmer, D.A.; Mesmer, R.E.

1995-12-31

408

Virtual instrumentation for pH measurements in biological systems.  

PubMed

In the present communication a personal computer control methodology for pH data acquisition and analysis in biological systems is reported. The instrumental control, acquisition, storage, processing and presentation of the experimental data are provided by a data acquisition board, a graphical programming software and numerical analysis/graphics software. The major objective of this work is to improve the performance and flexibility of the personal computer acquisition system compared with traditional approaches depending on potentiometric recorders. In particular, virtual instruments for interfacing pH meters of different brands to a personal computer and for measuring proton changes in lightly buffered solutions during enzymatic reactions are provided. PMID:10430463

Rigobello, M P; Cazzaro, F; Scutari, G; Bindoli, A

1999-07-01

409

pH microprobe manipulated in microchannels using optical tweezers  

NASA Astrophysics Data System (ADS)

SNARF-1 fluorochrome was used to functionalize 3?m diameter latex spheres making them sensitive to the pH of their environment, manifested as a change in their fluorescence. The fluorescence emission at 580nm was excited using a filtered xenon arc lamp at 515nm. A solution of functionalized latex spheres was placed between gold microelectrodes in a microfluidic channel. Optical tweezers were used to trap and manipulate the spheres in the vicinity of the microelectrodes, to map out the pH profile in the electrolyte solution, induced by passing 20 microsecond transient current pulses through the microelectrodes.

Sinclair, Gavin S.; Klauke, Norbert; Monaghan, Paul; Padgett, Miles J.; Cooper, Jon

2005-03-01

410

Enzyme Activity as a Function of pH  

NSDL National Science Digital Library

A matched pair of documents providing an introduction to the role of pH in the regulation of enzyme activity. The tutorial document contains all the equations and graphs for students to use to study the role of pH in enzyme kinetics. In the EnzymeExercise twin document all quations are omitted so that students can develop these interactively. The Exercise document is also ideal for display during lecture where the ideas can be developed interactively with the class as a whole.

411

Stress corrosion cracking properties of 15-5PH steel  

NASA Technical Reports Server (NTRS)

Unexpected occurrence of failures, due to stress corrosion cracking (SCC) of structural components, indicate a need for improved characterization of materials and more advanced analytical procedures for reliably predicting structures performance. Accordingly, the purpose of this study was to determine the stress corrosion susceptibility of 15-5PH steel over a wide range of applied strain rates in a highly corrosive environment. The selected environment for this investigation was a highly acidified sodium chloride (NaCl) aqueous solution. The selected alloy for the study was a 15-5PH steel in the H900 condition. The slow strain rate technique was selected to test the metals specimens.

Rosa, Ferdinand

1993-01-01

412

Influence of Tumor pH on Therapeutic Response  

Microsoft Academic Search

The intratumor microenvironment is intrinsically acidic due mainly to accumulation of lactic acid as a result of increased\\u000a aerobic and anaerobic glycolysis by the tumor cells. In general, the extracellular pH (pHe) in human tumors is below 7.0,\\u000a whereas the intracellular pH (pHi) is maintained at neutral range, i.e.,>7.0, by powerful pHi control mechanisms. The low\\u000a pHe and the significant

Chang W. Song; Robert Griffin; Heon Joo Park

413

Metal/Metal Oxide Differential Electrode pH Sensors  

NASA Technical Reports Server (NTRS)

Solid-state electrochemical sensors for measuring the degrees of acidity or alkalinity (in terms of pH values) of liquid solutions are being developed. These sensors are intended to supplant older electrochemical pH sensors that include glass electrode structures and reference solutions. The older sensors are fragile and subject to drift. The present developmental solid-state sensors are more rugged and are expected to be usable in harsh environments. The present sensors are based on a differential-electrode measurement principle. Each sensor includes two electrodes, made of different materials, in equilibrium with the solution of interest.

West, William; Buehler, Martin; Keymeulen, Didier

2007-01-01

414

Hypopharyngeal pH Monitoring Artifact in Detection of Laryngopharyngeal Reflux  

Microsoft Academic Search

Hypopharyngeal pH artifacts have been a concern in the detection of laryngopharyngeal reflux. Our purpose was to analyze and quantify artifacts from dual-sensor hypopharyngeal pH monitoring. In all, 42 hypopharyngeal and 58 esophageal pH studies were reviewed. Type 1 (out of range), type 2 (pH drift), and type 3 (isolated pH drop) artifacts were identified. The proportion of proximal-sensor pH

John M. Wo; Abdul Jabbar; Welby Winstead; Steve Goudy; Robert Cacchione; Jeff W. Allen

2002-01-01

415

Scale meter: a new method for determining the critical pH of scaling  

Microsoft Academic Search

A new understanding of the Saturation Index is presented which leads to the concept of a critical pH, the true pH of scaling. The critical pH is about 1.7 to 2.0 pH units higher than the pH of saturation predicted by the index. The method of determining the critical pH is described as is a continuous controller which utilizes this

Feitler

1972-01-01

416

High Mg effective incorporation in Al-rich Al x Ga1 - x N by periodic repetition of ultimate V/III ratio conditions  

PubMed Central

According to first-principles calculations, the solubility of Mg as a substitute for Ga or Al in Al x Ga1 – x N bulk is limited by large, positive formation enthalpies. In contrast to the bulk case, the formation enthalpies become negative on Al x Ga1 – x N surface. In addition, the N-rich growth atmosphere can also be favorable to Mg incorporation on the surface by changing the chemical potentials. On the basis of these special features, we proposed a modified surface engineering technique that applies periodical interruptions under an ultimate V/III ratio condition (extremely N-rich), to enhance Mg effective incorporation. By optimizing the interruption conditions (2 nm interruption interval with 2 s interruption time), the enhancement ratio can be up to about 5 in the Al0.99Ga0.01N epilayer.

2014-01-01

417

Dihydro-1,4-benzothiazine-6,7-dione, the ultimate toxic metabolite of 4-S-cysteaminylphenol and 4-S-cysteaminylcatechol.  

PubMed

4-S-Cysteaminylphenol (4-S-CAP) and the corresponding catechol 4-S-cysteaminylcatechol (4-S-CAC) have been evaluated for melanocytotoxicity. It was shown recently that tyrosinase oxidation of these substrates produces a violet pigment, dihydro-1,4-benzothiazine-6,7-dione (BQ). In this study we examined whether BQ is the ultimate toxic metabolite produced in melanoma cells from 4-S-CAP/4-S-CAC. Biochemical experiments showed that (1) BQ was formed by autoxidation of 4-S-CAC as well as by tyrosinase oxidation of 4-S-CAP/4-S-CAC, (2) BQ reacted rapidly with thiols such as reduced glutathione (GSH), and (3) BQ inhibited the activity of alcohol dehydrogenase, an SH enzyme. In vitro experiments showed that (1) the cytotoxicity of 4-S-CAC was mostly prevented by catalase and superoxide dismutase, (2) BQ was highly cytotoxic to B16 melanoma cells (IC50 being 3.9 microM as compared with 507 microM for 4-S-CAP), (3) BQ was metabolized rapidly to a GSH adduct in melanoma cells, and (4) the same GSH adduct was also formed upon incubation of melanoma cells with 4-S-CAP, the reaction being tyrosinase dependent. In vivo experiments showed that intratumoral administration of BQ (0.5 micromol) inhibited the subcutaneous growth of B16 melanoma nearly as effectively as 4-S-CAP/4-S-CAC (20 micromol). These results indicate that BQ is the ultimate toxic metabolite produced by tyrosinase oxidation of 4-S-CAP/4-S-CAC. BQ deprives melanoma cells of GSH and may inactivate SH enzymes essential for DNA synthesis and cell proliferation by covalent binding through their cysteine residues, thereby exerting melanocytotoxicity. Cytotoxicity of 4-S-CAC depends mostly on autoxidation producing BQ and active oxygens. PMID:9260870

Hasegawa, K; Ito, S; Inoue, S; Wakamatsu, K; Ozeki, H; Ishiguro, I

1997-05-15

418

Multidrug resistance-associated proteins are involved in the transport of the glutathione conjugates of the ultimate carcinogen of benzo[a]pyrene in human Caco-2 cells.  

PubMed

A wide variety of contaminants are ingested through food, among them the pro-carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene (BP) that is resorbed and partially metabolized in the enterocytes of the small intestine. Previous in vitro studies have revealed that BP phenols are excreted as Phase II metabolites including glucuronides and sulfates. This export is mediated by the breast cancer resistance protein (ABCG2). The ultimate carcinogenic Phase I BP metabolite anti-BP-7,8-dihydrodiol-9,10-epoxide (BPDE) can be detoxified by glutathione conjugate formation catalyzed by glutathione S-transferases. In the present study, differentiated human intestinal Caco-2 cells were used as a model for the human small intestine to investigate the detoxification of BPDE and excretion of stereoisomeric glutathione conjugates in the presence of an inhibitor of the glutathione-cleaving enzyme ?-glutamyl transpeptidase at the cell surface. The results indicate that the glutathione conjugates of BPDE are formed and excreted mainly to the apical and to a minor extent to the basolateral side of polarized Caco-2 monolayers. Inhibition studies revealed that the multidrug resistance-associated proteins (ABCCs) are involved in the transport of BPDE glutathione conjugates. Stable ABCC1, ABCC2 and ABCC3 knockdown cell lines were generated, thus making it possible to demonstrate that ABCC1 mediates the basolateral and ABCC2 the apical excretion of BPDE glutathione conjugates. In conclusion, the ultimate carcinogen BPDE is detoxified via glutathione conjugation and subsequently excreted by Caco-2 cells in both apical and basolateral directions. This finding is equivalent to a transport into feces as well as blood system in the in vivo situation. PMID:22899102

Hessel, Stefanie; John, Andrea; Seidel, Albrecht; Lampen, Alfonso

2013-02-01

419

Metallurgical Evaluation of 17-4 PH Stainless Steel Castings,  

National Technical Information Service (NTIS)

A metallurgical evaluation was conducted to determine if selected castings of 17-4 PH stainless steel used in head caps on missile weapon systems had been properly heat treated as required by SAE specification AMS-5355D. Optical metallographic analysis an...

G. E. Hicho J. H. Smith

1989-01-01

420

Interview Scheduling Strategies of New Ph.D. Economists.  

ERIC Educational Resources Information Center

Investigates the factors that affect procuring job interviews for new Ph.D. economists. Used a data set from the personal surveys of a cohort of first-time job seekers who attended the 1997 American Economic Association (AEA) meeting in New Orleans (Louisiana). States that estimation results suggest a heterogeneity in the interview decision across…

List, John A.

2000-01-01

421

Plastic optical fiber sensor for gastric ph detection  

Microsoft Academic Search

An optical fiber sensor for gastric pH detection is described, making use of plastic fibers as light carriers and a proper electronic system for both source driving and signal processing. The use of a suitable microprocessor and an internal buffer allows the realization of a portable and reliable device, fed by batteries. The indicators, bromophenol blue (BPB) or thymol blue

Francesco Baldini; Susanna Bracci; Franco Cosi

1994-01-01

422

Porous Fiber Optical Sensor For pH Measurement  

Microsoft Academic Search

summary: Numemus fiber optic pH sensors have been proposed in the past decade. Most of these sensors utilize polymers as a substrate to immobilize optically active organic indicatorsl32. However, these devices often exhibit significant degradation in the presence of organic solvents and are less stable at high temperatures or pressures typically encountered in many

J. Y. Ding; M. R. Shahriari; G. H. Sigel

1992-01-01

423

2D luminescence imaging of pH in vivo  

PubMed Central

Luminescence imaging of biological parameters is an emerging field in biomedical sciences. Tools to study 2D pH distribution are needed to gain new insights into complex disease processes, such as wound healing and tumor metabolism. In recent years, luminescence-based methods for pH measurement have been developed. However, for in vivo applications, especially for studies on humans, biocompatibility and reliability under varying conditions have to be ensured. Here, we present a referenced luminescent sensor for 2D high-resolution imaging of pH in vivo. The ratiometric sensing scheme is based on time-domain luminescence imaging of FITC and ruthenium(II)tris-(4,7-diphenyl-1,10-phenanthroline). To create a biocompatible 2D sensor, these dyes were bound to or incorporated into microparticles (aminocellulose and polyacrylonitrile), and particles were immobilized in polyurethane hydrogel on transparent foils. We show sensor precision and validity by conducting in vitro and in vivo experiments, and we show the versatility in imaging pH during physiological and chronic cutaneous wound healing in humans. Implementation of this technique may open vistas in wound healing, tumor biology, and other biomedical fields.

Schreml, Stephan; Meier, Robert J.; Wolfbeis, Otto S.; Landthaler, Michael; Szeimies, Rolf-Markus; Babilas, Philipp

2011-01-01

424

Improvements in Apparatus for Ph Measurement of Water.  

National Technical Information Service (NTIS)

An electronic device which automatically corrects the measurement of the pH of ammonia dosed power station boiler feedwater for changes in alkalinity brought about by the temperature dependence of the association of ammonia is described. It is noted that ...

I. R. Claxton

1979-01-01

425

Intracellular pH measurements using perfluorocarbon nanoemulsions.  

PubMed

We report the synthesis and formulation of unique perfluorocarbon (PFC) nanoemulsions enabling intracellular pH measurements in living cells via fluorescent microscopy and flow cytometry. These nanoemulsions are formulated to readily enter cells upon coincubation and contain two cyanine-based fluorescent reporters covalently bound to the PFC molecules, specifically Cy3-PFC and CypHer5-PFC conjugates. The spectral and pH-sensing properties of the nanoemulsions were characterized in vitro and showed the unaltered spectral behavior of dyes after formulation. In rat 9L glioma cells loaded with nanoemulsion, the local pH of nanoemulsions was longitudinally quantified using optical microscopy and flow cytometry and displayed a steady decrease in pH to a level of 5.5 over 3 h, indicating rapid uptake of nanoemulsion to acidic compartments. Overall, these reagents enable real-time optical detection of intracellular pH in living cells in response to pharmacological manipulations. Moreover, recent approaches for in vivo cell tracking using magnetic resonance imaging (MRI) employ intracellular PFC nanoemulsion probes to track cells using (19)F MRI. However, the intracellular fate of these imaging probes is poorly understood. The pH-sensing nanoemulsions allow the study of the fate of the PFC tracer inside the labeled cell, which is important for understanding the PFC cell loading dynamics, nanoemulsion stability and cell viability over time. PMID:24266634

Patrick, Michael J; Janjic, Jelena M; Teng, Haibing; O'Hear, Meredith R; Brown, Cortlyn W; Stokum, Jesse A; Schmidt, Brigitte F; Ahrens, Eric T; Waggoner, Alan S

2013-12-11

426

The social science PhD: A literature review  

Microsoft Academic Search

Following the Winfield Report on the social science PhD and the Economic and Social Research Council (ESRC) response to it, this literature review examines what research has been accomplished on the process of doctoral education in the social sciences. The review encompasses the debate over whether the focus of doctoral research should be education or training. Also examined are such

John Hockey

1991-01-01

427

Variation of RF of Vitamin B6 Group with PH.  

National Technical Information Service (NTIS)

The RF values of some members of the vitamin B6 complex have been reported to vary from run to run. A reinvestigation of these variable results revealed that the RF values of this group are a function of pH of the developing solvent at constant temperatur...

W. R. Gustavson G. Ledin A. Furst

1966-01-01

428

PhDs by Publications: An "Easy Way Out"?  

ERIC Educational Resources Information Center

PhDs by publications are a relatively new model for doctoral research, especially in the context of the Humanities or Education. This paper describes two writers' experiences of conducting doctoral studies in this genre and in these faculties. Each discover alternative ways of employing a body of published research papers in development of an…

Niven, Penelope; Grant, Carolyn

2012-01-01

429

Kids learn that physiology can be PhUn  

NSDL National Science Digital Library

A news article from The Miami Herald about PhUn Week 2009. "As part of a national campaign to acquaint students with exercise physiology and how their bodies work, students at South Miami Middle School participated in a week of fun activities."

Laura Morales (The Miami Herald)

2009-11-08

430

Microenvironment Changes (in pH) Affect VEGF Alternative Splicing  

PubMed Central

Vascular endothelial growth factor-A (VEGF-A) has several isoforms, which differ in their capacity to bind extracellular matrix proteins and also in their affinity for VEGF receptors. Although the relative contribution of the VEGF isoforms has been studied in tumor angiogenesis, little is known about the mechanisms that regulate the alternative splicing process. Here, we tested microenvironment cues that might regulate VEGF alternative splicing. To test this, we used endometrial cancer cells that produce all VEGF isoforms as a model, and exposed them to varying pH levels, hormones, glucose and CoCl2 (to mimic hypoxia). Low pH had the most consistent effects in inducing variations in VEGF splicing pattern (VEGF121 increased significantly, p?pH stimulation, blocking the shift in VEGF isoforms production. Taken together, we show for the first time that acidosis (low pH) regulates VEGF-A alternative splicing, may be through p38 activation and suggest the possible SR proteins involved in this process. Electronic supplementary material The online version of this article (doi:10.1007/s12307-008-0013-4) contains supplementary material, which is available to authorized users.

Elias, Ana Paula

2008-01-01

431

Output of Science Ph.D.'s will Continue Slide  

ERIC Educational Resources Information Center

Discusses a study which projects the future output of science doctoral degrees. The figures project the following decreases in Ph.D. productions: physical sciences, minus 51 percent; engineering, minus 32 percent; and mathematics, minus 50 percent; and the following increases during the same period: social sciences, 41 percent; and life sciences,…

Murray, Chris

1975-01-01

432

Ph.D. Outlook: Too Many for Too Few Jobs.  

ERIC Educational Resources Information Center

Discusses a report which concludes that the number of science and engineering Ph.D's in the labor force will increase nearly 50 percent by 1987, while the number of "traditional" employment positions will increase only 35 percent, forcing more and more of the degree holders to work outside their fields. (GA)

Chemical and Engineering News, 1979

1979-01-01

433

Factors Influencing Successful Submission of PhD Theses  

Microsoft Academic Search

This article examines the submission rates of 3579 postgraduate research students who studied for the traditional PhD degree at a single large civic university between 1984 and 1993. An examination is made of individual factors which may have an effect on students' rate of completion, attempting to identify characteristics of the student 'most likely to succeed'. The analysis excludes intrinsic

Toni Wright; Ray Cochrane

2000-01-01

434

Cancer Genes: Discovery and Function - Michael Dean, Ph.D.  

Cancer.gov

April 29, 2014 1:00 PM - 2:00 PM Shady Grove, Room TE408/410 + Add to Outlook Calendar Speaker: Michael Dean, Ph.D. Chief, Human Genetics Section Laboratory of Experimental Immunology, CCR, NCI Print This Page Cancer Genes: Discovery and Function

435

Improved pH buffering agent for sodium hypochlorite  

NASA Technical Reports Server (NTRS)

Sodium citrate/citric acid was found to be an effective buffer for pH control when used with sodium hypochlorite. The mixture does not corrode aluminum. The buffer appears to form a type of conversion coating that may provide corrosion-resistant properties to aluminum in other applications.

Nash, J. R.; Veeder, L. N.

1969-01-01

436

A Smooth Passage toward an Online PhD  

ERIC Educational Resources Information Center

There is a need for research into understanding students' learning barriers and cognitive style of learning before they embark on an online PhD program. Online university students in the School of Education express success and difficulties electronically as they navigate through a spectrum of courses, Learning Agreements, Knowledge Area Modules…

Cleeton, Lorraine; Cleeton, Gilbert

2006-01-01

437

Gaseous hydrogen embrittlement of PH 13-8 Mo steel  

Microsoft Academic Search

In this study, notched tensile and fatigue crack growth tests in gaseous hydrogen were performed on PH 13-8 Mo stainless steel specimens at room temperature. These specimens were susceptible to hydrogen embrittlement (HE), but at different degrees, depending on the aging conditions or the microstructures of the alloys. In hydrogen, the accelerated fatigue crack growth rate (FCGR) usually accompanied a

Y. S. Ding; L. W. Tsay; M. F. Chiang; C. Chen

2009-01-01

438

Evaluation of Armco PH13-8Mo.  

National Technical Information Service (NTIS)

The PH-13 13-8 Mo is a precipitation hardenable stainless steel. This steel can be heat treated to 225 ksi and has excellent toughness, general corrosion, and stress corrision at this strength level. The fatigue life is comparable to 4330 in both the smoo...

J. M. Uchida

1969-01-01

439

PhAst: A Flexible IDL Astronomical Image Viewer  

NASA Astrophysics Data System (ADS)

We present near-Earth asteroid data analyzed with PhAst, a new IDL astronomical image viewer based on the existing application ATV. PhAst opens, displays, and analyzes an arbitrary number of FITS images. Analysis packages include image calibration, photometry, and astrometry (provided through an interface with SExtractor, SCAMP, and missFITS). PhAst has been designed to generate reports for Minor Planet Center reporting. PhAst is cross platform (Linux/Mac OSX/Windows for image viewing and Linux/Mac OSX for image analysis) and can be downloaded from the following website at NOAO: http://www.noao.edu/staff/mighell/phast/. Rehnberg was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 13 (AST-0754223) of the Cooperative Agreement No. AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.

Rehnberg, Morgan; Crawford, R.; Trueblood, M.; Mighell, K.

2012-01-01

440

The Production Rate and Employment of Ph.D. Astronomers  

NASA Astrophysics Data System (ADS)

As in many sciences, the production rate of new Ph.D. astronomers is decoupled from the global demand for trained scientists. As noted by Thronson (1991, PASP, 103, 90), overproduction appears to be built into the system, making the mathematical formulation of surplus astronomer production similar to that for industrial pollution models -- an unintended side effect of the process. Following Harris (1994, ASP Conf., 57, 12), I document the production of Ph.D. astronomers from 1990 to 2005 using the online Dissertation Abstracts database. To monitor the changing patterns of employment, I examine the number of postdoctoral, tenure-track, and other jobs advertised in the AAS Job Register during this same period. Although the current situation is clearly unsustainable, it was much worse a decade ago with nearly 7 new Ph.D. astronomers in 1995 for every new tenure-track job. While the number of new permanent positions steadily increased throughout the late 1990's, the number of new Ph.D. recipients gradually declined. After the turn of the century, the production of new astronomers leveled off, but new postdoctoral positions grew dramatically. There has also been recent growth in the number of non-tenure-track lecturer, research, and support positions. This is just one example of a larger cultural shift to temporary employment that is happening throughout society -- it is not unique to astronomy.

Metcalfe, Travis S.

2007-05-01

441

Electrochemical Stability of Polyaniline Beyond pH 9  

NASA Astrophysics Data System (ADS)

Conductive polymer films are promising candidates for solution-based biosensor and organic electrochemical transistor devices. For many conducting polymers, however, stable electrochemical activity often demands restrictively acidic solutions. This need has in turn limited the use of conductive polymers in near-neutral and physiological conditions. Using spectroelectrochemical methods, we studied the stability of polyaniline that is template synthesized on poly(2-acrylamido-2-methyl-1-propanesulfonic acid) as a function of pH. Transitions between the different oxidation states of polyaniline are stable and reversible in solutions as high as pH 10. This range of sustained electroactivity far exceeds that of previously reported polyaniline systems. In comparison, polyaniline that is doped with small-molecule acids loses its electroactivity in solutions beyond pH 4. Immobilization of polyaniline within a polymer acid matrix retards dopant diffusivity and reduces proton mobility. The preservation of local acidic conditions within the film greatly extends the pH range of stable electroactivity.

Tarver, Jacob; Yoo, Joung Eun; Loo, Yueh-Lin

2009-03-01

442

pH Sensors Based on Iridium Oxide.  

National Technical Information Service (NTIS)

Results are presented on the pH-potential response of d.c. magnetron reactively sputtered iridium oxide films. The films exhibit a nearly Nernstian response to pH, no hysteresis effects, and minimal response to ionic interferences. Sensitivity to certain ...

M. J. Tarlov K. G. Kreider S. Semancik P. Huang

1990-01-01

443

Octocoral Tissue Provides Protection from Declining Oceanic pH.  

PubMed

Increase in anthropogenic pCO2 alters seawater chemistry and could lead to reduced calcification or skeleton dissolution of calcifiers and thereby weaken coral-reef structure. Studies have suggested that the complex and diverse responses in stony coral growth and calcification, as a result of elevated pCO2, can be explained by the extent to which their soft tissues cover the underlying skeleton. This study compared the effects of decreased pH on the microstructural features of both in hospite (within the colony) and isolated sclerites (in the absence of tissue protection) of the zooxanthellate reef-dwelling octocoral Ovabunda macrospiculata. Colonies and isolated sclerites were maintained under normal (8.2) and reduced (7.6 and 7.3) pH conditions for up to 42 days. Both in hospite and isolated sclerites were then examined under SEM and ESEM microscopy in order to detect any microstructural changes. No differences were found in the microstructure of the in hospite sclerites between the control and the pH treatments. In stark contrast, the isolated sclerites revealed dissolution damage related to the acidity of the water. These findings suggest a protective role of the octocoral tissue against adverse pH conditions, thus maintaining them unharmed at high pCO2. In light of the competition for space with the less resilient reef calcifiers, octocorals may thus have a significant advantage under greater than normal acidic conditions. PMID:24710022

Gabay, Yasmin; Fine, Maoz; Barkay, Zahava; Benayahu, Yehuda

2014-01-01

444

Troubling Talk: Assembling the PhD Candidate  

ERIC Educational Resources Information Center

When PhD students complain it is assumed there are problems and that troubles talk is evidence of a "sick" research candidature or culture. This paper argues that such a one-dimensional reading fails to attend closely to the academic identity work that is done when students talk together. Identity work has become a useful way of thinking about the…

Mewburn, I.

2011-01-01

445

The Role of pH Fronts in Reversible Electroporation  

PubMed Central

We present experimental measurements and theoretical predictions of ion transport in agar gels during reversible electroporation (ECT) for conditions typical to many clinical studies found in the literature, revealing the presence of pH fronts emerging from both electrodes. These results suggest that pH fronts are immediate and substantial. Since they might give rise to tissue necrosis, an unwanted condition in clinical applications of ECT as well as in irreversible electroporation (IRE) and in electrogenetherapy (EGT), it is important to quantify their extent and evolution. Here, a tracking technique is used to follow the space-time evolution of these pH fronts. It is found that they scale in time as , characteristic of a predominantly diffusive process. Comparing ECT pH fronts with those arising in electrotherapy (EChT), another treatment applying constant electric fields whose main goal is tissue necrosis, a striking result is observed: anodic acidification is larger in ECT than in EChT, suggesting that tissue necrosis could also be greater. Ways to minimize these adverse effects in ECT are suggested.

Turjanski, Pablo; Olaiz, Nahuel; Maglietti, Felipe; Michinski, Sebastian; Suarez, Cecilia; Molina, Fernando Victor; Marshall, Guillermo

2011-01-01

446

The role of pH fronts in reversible electroporation.  

PubMed

We present experimental measurements and theoretical predictions of ion transport in agar gels during reversible electroporation (ECT) for conditions typical to many clinical studies found in the literature, revealing the presence of pH fronts emerging from both electrodes. These results suggest that pH fronts are immediate and substantial. Since they might give rise to tissue necrosis, an unwanted condition in clinical applications of ECT as well as in irreversible electroporation (IRE) and in electrogenetherapy (EGT), it is important to quantify their extent and evolution. Here, a tracking technique is used to follow the space-time evolution of these pH fronts. It is found that they scale in time as t(½), characteristic of a predominantly diffusive process. Comparing ECT pH fronts with those arising in electrotherapy (EChT), another treatment applying constant electric fields whose main goal is tissue necrosis, a striking result is observed: anodic acidification is larger in ECT than in EChT, suggesting that tissue necrosis could also be greater. Ways to minimize these adverse effects in ECT are suggested. PMID:21559079

Turjanski, Pablo; Olaiz, Nahuel; Maglietti, Felipe; Michinski, Sebastian; Suárez, Cecilia; Molina, Fernando Victor; Marshall, Guillermo

2011-01-01

447

Octocoral Tissue Provides Protection from Declining Oceanic pH  

PubMed Central

Increase in anthropogenic pCO2 alters seawater chemistry and could lead to reduced calcification or skeleton dissolution of calcifiers and thereby weaken coral-reef structure. Studies have suggested that the complex and diverse responses in stony coral growth and calcification, as a result of elevated pCO2, can be explained by the extent to which their soft tissues cover the underlying skeleton. This study compared the effects of decreased pH on the microstructural features of both in hospite (within the colony) and isolated sclerites (in the absence of tissue protection) of the zooxanthellate reef-dwelling octocoral Ovabunda macrospiculata. Colonies and isolated sclerites were maintained under normal (8.2) and reduced (7.6 and 7.3) pH conditions for up to 42 days. Both in hospite and isolated sclerites were then examined under SEM and ESEM microscopy in order to detect any microstructural changes. No differences were found in the microstructure of the in hospite sclerites between the control and the pH treatments. In stark contrast, the isolated sclerites revealed dissolution damage related to the acidity of the water. These findings suggest a protective role of the octocoral tissue against adverse pH conditions, thus maintaining them unharmed at high pCO2. In light of the competition for space with the less resilient reef calcifiers, octocorals may thus have a significant advantage under greater than normal acidic conditions.

Gabay, Yasmin; Fine, Maoz; Barkay, Zahava; Benayahu, Yehuda

2014-01-01

448

DCEG Seminar in April: Jonine Figueroa, Ph.D.  

Cancer.gov

April 17, 2014 10:30 AM - 11:30 AM + Add to Outlook Calendar Speaker Jonine D. Figueroa, Ph.D. Investigator, Hormonal and Reproductive Epidemiology Branch Division of Cancer Epidemiology and Genetics, National Cancer Institute Title: TBA Location: Shady

449

DISSOLVED ORGANIC MATTER AND METALS: EFFECTS OF PH ON PARTITIONING  

EPA Science Inventory

Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb, and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was fractionated into three operationally defined fractions: hydrophilic acids (Hyd), fulvic acids (FA), an...

450

[Regulation effects of tourmaline on seawater pH value].  

PubMed

In this paper, chemical analysis, X-ray diffraction and atomic force microscopy were employed to examine the characteristics of tourmaline produced in east Inner Mongolia Autonomous Region, and batch experiments were conducted to study its regulation effects on seawater pH value. The factors affecting the regulation, such as the dosage of tourmaline and the salinity and initial pH value of seawater, were also studied. The results showed that tourmaline could regulate the seawater pH value from its initial 3 and 10 to 7.1 and 8.9, respectively, and the regulation effect was greater in the seawater with lower salinity, e.g., after 120 minutes treatment, the initial pH value (5.0) of the seawater with a salinity of 5, 10, 15, 20 and 35 was increased by 3.24, 3.16, 3.06, 2.99 and 2.85 unit, respectively. Tourmaline had little effect on seawater conductivity. This study would provide an experimental base for the application of tourmaline in aquaculture. PMID:16422525

Xia, Meisheng; Zhang, Hongmei; Hu, Caihong; Xu, Zirong

2005-10-01

451

Gender Differences in Research Patterns among PhD Economists  

ERIC Educational Resources Information Center

This study is based on a 1996 survey of PhD economists working in the academic and nonacademic sectors since 1989. Despite a raw gender difference in all types of research output, the male dummy variable proves statistically significant in predicting only one publication measure. In a full sample and faculty subsample, number of years since…

Barbezat, Debra A.

2006-01-01

452

PHYSICOCHEMICAL FACTORS AFFECTING TOXICITY IN FRESHWATER: HARDNESS, PH, AND TEMPERATURE  

EPA Science Inventory

A search of the literature for effects of hardness, pH, or temperature on the toxicity of chemicals to freshwater organisms suggested that the amount of reliable and useful data is limited. uch of the disparity among results reported in the literature was caused by improperly des...

453

Effects of pH on aquatic biodegradation processes  

NASA Astrophysics Data System (ADS)

To date, little is known about the pH-stimulated mineralization of organic matter in aquatic environments. In this study, we investigated biodegradation processes in alkaline waters. Study site is a large shallow soda lake in Central Europe (Neusiedler See/Ferto). The decomposition rate of plant litter was measured as a function of pH by incubating air-saturated lake-water samples in contact with Phragmites litter (leaves) from the littoral vegetation. All samples showed high decomposition rates (up to 32% mass loss within 35 days) and a characteristic two-step degradation mechanism. During the degradation process, the solid plant litter was dissolved forming humic colloids. Subsequently, the humic colloids were mineralized to CO2 in the water column. The decomposition rate was linearly related to pH. Increasing pH values accelerated significantly the leaching of humic colloids as well as the final degradation process. The observed two-step mechanism controls the wetland/lake/air carbon fluxes, since large quantities of humic colloids are currently produced in the reed belt, exported through wind-driven circulations and incorporated into the open lake foodweb. At present, the lake is rapidly shrinking due to peat deposition in the littoral zone, whereas it has been resistant to silting-up processes for thousands of years. In order to investigate the cause of this abrupt change, the chemical composition of the lake-water was measured during 1995-2007. A thorough analysis of these data revealed that major lake-water discharges through the lake's artificial outlet channel led to a decline in salinity and alkalinity. According to our estimates, the lake's