cssi/SciSciGPT-SciSciNet huggingface dataset:
Mesoscale modeling of the influence of morphology on the mechanical properties of proton exchange membranes

Abstract The nano-scale morphology of a proton exchange membrane (PEM) strongly influences its proton conductivity and mechanical performance. In this paper, a multi-scale modeling approach has been developed to obtain the morphologies of hydrated perfluorosulfonic acid (PFSA) membranes and then to predict their mechanical properties based on the simulated morphology. Two representative ionic domain morphologies were compared, spherical and cylindrical, to represent cast and extruded membranes. The calculated overall elastic Young’s moduli are very close for both morphologies and agree well with experiments. The nano-scale phase segregation in hydrated PFSA induces a non-uniform distribution of local stress. The peak stress is localized at the smeared water/PFSA interface. The cylindrical morphology develops much lower peak stress than the isotropic spherical morphology under the same level of strain. These results explain why the extruded membranes show more than 10 times longer life in durability tests than recast membranes, despite having similar bulk moduli.
Brevetoxin exposure in bottlenose dolphins (Tursiops truncatus) associated with Karenia brevis blooms in Sarasota Bay, Florida

Bottlenose dolphins (Tursiops truncatus) face a variety of threats, including risk of exposure to brevetoxins produced by blooms of the harmful alga Karenia brevis. This study investigated brevetoxin exposure in a population of dolphins inhabiting Sarasota Bay, Florida, USA (27°N, 82°W), utilizing tissues from dolphins recovered between 1994 and 2003. Brevetoxin levels detected by ELISA in tissues, gastric samples and excreta from dolphin carcasses (n = 19) associated with K. brevis blooms were compared with with levels in carcasses (n = 16) associated with background K. brevis conditions. In the K. brevis-exposed set, 84% of dolphin carcasses recovered during K. brevis blooms had detectable brevetoxin levels, with values ranging between 7 and 2,896 ng PbTx-3 eq g−1. Over 50% of dolphin carcasses recovered during non-bloom conditions also tested positive by ELISA for brevetoxins, with concentrations ranging from 6 to 44 ng PbTx-3 eq g−1. Control samples from the east coast of Florida were negative by the ELISA. Results from this study establish baseline brevetoxin body burdens in a dolphin population frequently exposed to K. brevis blooms, and data indicate that dolphin carcasses not associated with large-scale mortality events can contain levels of brevetoxins comparable to carcasses stranding during such events.
Who should determine when health care is medically necessary

In the United States there has been a radical shift in the power to determine when health care is medically necessary and therefore covered by insurance. From the 1950s through the late 1970s, phys...
A computer program to study image formation of small blood vessels.

Abstract A computer program is described which facilitates the rapid assessment of a number of physical parameters affecting the image formation of small blood vessels. These parameters are: the dimensions of the focus, the intensity distribution of the emitted photons over the focus area, the energy spectrum of the emitted photons, the attenuation by the contrast agent used, and the geometry of the exposure. Independently measured or calculated values of the above parameters are used in the program. The output of these values is a map of the intensity distribution of X rays in the image plane during a simulated exposure of a small blood vessel.
Morphologic alterations in somatotrophs of the rat adenohypophysis following administration of hypothalamic extracts

Hypothalamic extracts injected intravenously into rats produced morphologic alterations in somatotrophs of the pars distalis as observed with light and electron microscopy. Histological changes were correlated with pituitary growth hormone content as determined by bioassay by the tibia test in the same tissue samples. Statistical analysis of data derived from fine structure (number of secretory granules/somatotroph profile) was useful as an index of granule storage and release. Increased numbers of secretory granules, hypertrophy of the Golgi complex, and increased granule extrusion which were observed within five minutes after injection of hypothalamic extract supported the concept that growth hormone-relasing factor in the hypothalamic extract was effective not only in releasing growth hormone but also in stimulating its biosynthesis. Significant increases in both growth hormone content and granule counts agreed with this concept. Extremes of granulation and variable organelle morphology were apparent 15 minutes after injection with hypothalamic extract, although overall granule counts and bioassable growth hormone were within normal limits. By 30 minutes somatotrophs depleted of granules were common, suggesting granule release of major proportion which was consistent with significant decreases in number of granules and growth hormone content. Granules remaining in somatotrophs were aligned peripherally. Vesicular Golgi complexes were prominent. Increased numbers of presumed lysosomes may be related to membrane and/or secretory product accumulation which may result from granule synthesis and release. Somatotrophs from control rats appeared normal.
Commitment, Learning, and Alliance Performance: A Formal Analysis Using an Agent-Based Network Formation Model

Current theoretical arguments highlight a dilemma faced by actors who either adopt a weak or strong commitment strategy for managing their alliances and partnerships. Actors who pursue a weak commitment strategy—that is, immediately abandon current partners when a more profitable alternative is presented—are more likely to identify the most rewarding alliances. On the other hand, actors who enact a strong commitment approach are more likely to take advantage of whatever opportunities can be found in existing partnerships. Using agent-based modeling, we show that actors who adopt a moderate commitment strategy overcome this dilemma and outperform actors who adopt either weak or strong commitment approaches. We also show that avoiding this dilemma rests on experiencing a related tradeoff: moderately-committed actors sacrifice short-term performance for the superior knowledge and information that allows them to eventually do better. [Supplementary material is available for this article. Go to the publisher's...
MT2-MMP-Dependent Release of Collagen IV NC1 Domains Regulates Submandibular Gland Branching Morphogenesis

Summary Proteolysis is essential during branching morphogenesis, but the roles of MT-MMPs and their proteolytic products are not clearly understood. Here, we discover that decreasing MT-MMP activity during submandibular gland branching morphogenesis decreases proliferation and increases collagen IV and MT-MMP expression. Specifically, reducing epithelial MT2-MMP profoundly decreases proliferation and morphogenesis, increases Col4a2 and intracellular accumulation of collagen IV, and decreases the proteolytic release of collagen IV NC1 domains. Importantly, we demonstrate the presence of collagen IV NC1 domains in developing tissue. Furthermore, recombinant collagen IV NC1 domains rescue branching morphogenesis after MT2-siRNA treatment, increasing MT-MMP and proproliferative gene expression via β1 integrin and PI3K-AKT signaling. Additionally, HBEGF also rescues MT2-siRNA treatment, increasing NC1 domain release, proliferation, and MT2-MMP and Hbegf expression. Our studies provide mechanistic insight into how MT2-MMP-dependent release of bioactive NC1 domains from collagen IV is critical for integrating collagen IV synthesis and proteolysis with epithelial proliferation during branching morphogenesis.
Genetic Sensitivity to 6-N-Propylthiouracil (prop) and Sensory Acceptance of Soy Products and Japanese Green Tea.

Abstract LEARNING OUTCOME: Sensory acceptance of functional foods, with reputed cancer preventive properties, such as soy products and Japanese green tea, may be influenced by genetic sensitivity to the bitter taste of PROP. Subjects were 53 young women (ages 20-45 y) recruited from the University of Michigan community. Taste detection thresholds for 6- n -propylthiouracil (PROP) were determined using the method of solutions. The subjects also tasted 5 suprathreshold solutions each of PROP and NaCl. Separation of subjects into nontasters (n=14), regular tasters (n=27) and supertasters (n=12) of PROP was based on PROP detection thresholds and mean response ratios to PROP as compared to NaCl solutions. The subjects also tasted a range of soy products including tofu, miso, plain soy milk and vanilla-flavored soy milk, as well as five different concentrations of Japanese green tea presented at room temperature. The most concentrated tea sample used 2.25g of tea per 50ml water, infused over a 5min period. Taste intensity ratings were recorded using 9-point category scales, while acceptability ratings were based on a 9-point hedonic preference scale. Results showed that tasters and supertasters of PROP found tofu less acceptable than did nontasters, and to the contrary, preferred sweetened vanilla-flavored soy milk. PROP tasters rated Japanese green tea as more bitter than did nontasters. Rated acceptance of green tea decreased as bitterness increased. In past studies, genetically mediated sensitivity to PROP predicted lower acceptance of grapefruit juice. Since potentially chemopreventive flavonoids in soy products and green tea also have a bitter taste, avoidance of bitter foods may alter eating habits and reduce dietary exposure to foods known to alter cancer risk. Supported by NCI grant CA61680 and funds from the Michigan Soybean Promotion Board.
Protein-Protein Interactions And The Energy Coupling Mechanism In TonB-Dependent Transport

BtuB is a TonB-dependent outer membrane transporter of vitamin B12 in E. coli. In this work, we investigated the interaction between BtuB and the inner membrane protein TonB using site-directed spin labeling (SDSL). In CHAPS/POPC mixed micelles, the Ton box of BtuB undergoes an order-to-disorder transition upon addition of vitamin B12 which appears to be identical to that seen in POPC bilayers. Under these conditions, addition of a C-terminal fragment of TonB broadens the EPR lineshapes, indicating that there is an ordering of the Ton box and an interaction between the transporter Ton box and this C-terminal fragment. Residues N-terminal to the Ton box do not appear to interact with TonB. These changes appear to be independent of the addition of the substrate, vitamin B12. The EPR data obtained are generally consistent with the crystal structure that has been obtained for this complex (Shultis et al. Science 312, (2006)); however, preliminary distance measurements using DEER indicate that there may be multiple states of TonB when it is bound to BtuB. Spin labels incorporated into TonB also become ordered upon interaction with BtuB, and the EPR lineshapes indicate that there is a decrease in backbone dynamics of TonB upon association with BtuB. An EPR based equilibrium binding assay was carried out to determine the affinity between this C-terminal TonB fragment and BtuB, and was performed using either labels on BtuB or labels on TonB. Both labels indicate that there is an affinity of approximately 50 μM between BtuB and TonB, which is, unexpectedly, independent of substrate addition.This work was supported by GM035215.
A Critical Evaluation of Carotid Duplex Scanning in the Diagnosis of Significant Carotid Artery Occlusive Disease

Carotid duplex (CD) scanning is the primary method of evaluating patients suspected of having extracranial carotid occlusive disease. It is incumbent on vascular laboratories (VL) to have internally validated criteria confirming overall accuracy, specificity (SP), sensitivity (SS), negative predictive value (NPV), and positive predictive value (PPV). Receiver operating characteristic (ROC) curves allow further analysis to update existing criteria. We correlated 127 internal carotid arteries studied by carotid duplex scanning and confirmatory modalities, which showed a SP of 83.3%, SS of 97.9%, NPV of 92.5%, PPV of 95%, and overall accuracy of 94.5% for >50% internal carotid artery stenosis. For >70% stenosis, SP was 88.8%, SS was 96.1%, NPV was 93.6%, PPV was 92.5%, and overall accuracy was 92.9%. ROC curves for the peak systolic velocities were used; for detecting a 50–69% stenosis range a sensitivity of 88%, specificity of 93%, NPV of 73%, and PPV of 97% were found. For detecting a 70–99% stenosis a sensitivity of 95%, specificity of 90%, NPV of 93%, and a PPV of 93% were found. All vascular laboratories must have a vigorous quality assurance program and must validate their own internal criteria or the recently promulgated consensus criteria for grading the severity of carotid stenosis by carotid duplex examination.
Assay, purification, and properties of bovine liver D-xylulokinase

Convenient specific assay methods using commercially available materials were developed for the measurement of D-xylulokinase and D-ribulokinase activities. Using these assays, D-xylulokinase from bovine liver has been purified to homogeneity. Purification involved column chromatography on DEAE-cellulose, Sephadex G-100, Dyematrex Red A, and Superose 12. The enzyme preparation was obtained with final yields of 15-30% and had activity toward both D-xylulose and D-ribulose. The final specific activities ranged from 2.5 to 7.5 and 1.9 to 5.9 mol/min for the two substrates and Km values of 0.14 and 0.27 mM were obtained, respectively. For ATP, a Km value of 0.080 mM was obtained with either substrate. AMP, ADP, and cAMP inhibited competitively with respect to ATP; Ki values were 0.34, 0.35, and 1.0 mM, respectively. Xylulokinase thus prepared was a monomeric protein of 51,000 Da and had a pH optimum between 7.4 and 8.2. The kinetics of the enzyme do not support any significant regulation of flux through the enzyme by metabolite level changes.
Automatic selection of a linear predictor through frequency domain cross-validation

Given data from a weakly stationary stochastic process in discrete time, and any L-step ahead linear predictor estimated from that data, we will construct an approximately unbiased estimator of the resulting mean squared error of L-step ahead linear prediction. The motivation for the estimator is based on frequency domain cross-validation, and hence the range of validity and applicability of the resulting selection method is not limited by particular assumptions about the structure of the underlying stochastic process or the form of the fitted linear predictors. We also propose a new frequency domain predictor fitting method. The method provides a natural finite-past analog to the existing spectral factorization techniques, and it compares favorably with the existing techniques, both asymptotically and for finite samples. In a Monte Carlo study, we compare several predictor selection methods, at lead times one and five. The performance criterion used is the mean squared prediction error of the selected pr...
An interactive computer program can effectively educate patients about genetic testing for breast cancer susceptibility.

As genetic testing for susceptibility to breast cancer becomes more widespread, alternative methods for educating individuals prior to testing will be needed. Our objective was to compare face-to-face education and counseling by a genetic counselor with education by an interactive computer program, assessing the effects of each on knowledge of breast cancer genetics and intent to undergo genetic testing. We used a randomized, controlled trial. Seventy-two self-referred women with a first-degree relative with breast cancer received outpatient education and counseling at the Clinical Center of the National Institutes of Health (NIH). Twenty-nine received individualized counseling from a genetic counselor (counseling group), 29 received education from an interactive computer program followed by individualized counseling (computer group), and 14 were controls. Both pre- and postintervention assessment of knowledge about breast cancer genetics and intent to undergo genetic testing were measured. The control group participants correctly answered 74% of the knowledge questions; the counselor group, 92%; and the computer group, 96% (P < .0001). Unadjusted mean knowledge scores were significantly higher in the computer group than the counselor group (P =.048), but they were equivalent when adjusted for demographic differences (P = 0.34). Intent to undergo genetic testing was influenced by the interventions: preintervention, a majority in all groups (69%) indicated that they were likely (definitely and most likely) to undergo testing; after either intervention coupled with counseling, only 44% indicated that they were likely to do so (P =.0002; odds ratio = 2.8, 95% CI = 1.7-4.9). We concluded that a computer program can successfully educate patients about breast cancer susceptibility, and, along with genetic counseling, can influence patients' intentions to undergo genetic testing. (C) 2001 Wiley-Liss, Inc.
A comparison of two timed-mating strategies for breeding pigtail monkeys. (Macaca nemestrina)

Abstract Pigtail monkeys ( Macaca nemestrina ) were time-mated using female perineal “sex skin” tumescence cyclicity as an indicator of ovulation time. The goal of these matings was production of infants of known gestational age for an investigation using a nonhuman primate model to study causes, correlates, and consequences of premature birth. Two breeding strategies were employed. The first involved allowing breeders constant access to one another for 72 hours at the time ovulation was predicted to occur from previous data on cyclicity of perineal tumescence. The second method limited exposure to two hours daily until perineal detumescence occurred. The second strategy has been considerably more effective than the first.
Nanocomposites derived from sulfonated poly(butylene terephthalate)

The effect of sodium sulfonate functionalization of poly(butylene terephthalate) (PBT) on the properties of PBT/montmorillonite composites was studied. The results of the study clearly showed that ...
Rush immunotherapy in a dog with severe ragweed and grass pollen allergy.

Background Forty years of study of naturally occurring IgE-mediated allergy in animals is briefly reviewed. These studies provided models for study of bioactive mediators and innovative pharmacologic therapies for IgE-mediated asthma. Objective Based on our experience with canine allergy we evaluated and treated a dog with severe grass and ragweed allergy whose allergic dermatitis was uncontrolled by H 1 blockers and topical corticosteroids. The dog was miserable during the Chicago grass and ragweed pollen seasons. Methods Rush immunotherapy was initiated during the ragweed season of 1997. Results Dramatic improvement was seen which persisted through the grass and ragweed seasons of 1998 after maintenance immunotherapy. Conclusion The case is presented not as a model for canine immunotherapy but as an example of how animal research can be of value to both animals and humans.
Investment prospects for geothermal power in El Salvador's electricity market

Abstract A mixed-integer optimizing programming model was created to simulate capacity expansion for the electricity market in El Salvador. Various demand scenarios were constructed, under which capacity expansion alternatives were tested. Results showed that possible geothermal projects were able to meet the growing energy needs of El Salvador, while yielding relatively low prices for the end-user. A best case projection for 2020 showed an increased proportion of geothermal generation in the energy mix by 6% compared to the present mix. Much of the current generating plants and planned capacity are distanced from the load center, San Salvador. In order to meet the country's increasing demand, it was found that generating capacity investment should be accompanied by transmission upgrades. Even when current conditions were simulated, transmission congestion appeared to be present. Results from some expansion scenarios showed that transmission congestion increased nodal prices despite the addition of further generating capacity.
Medical management of atrial fibrillation: Future directions

Atrial fibrillation is the most common arrhythmia that requires treatment, and although ablation is appropriate in many cases, antiarrythmic drug therapy remains the first and most appropriate therapy in most patients. Currently available antiarrhythmic drugs are limited by modest efficacy and significant toxicity. Cardiac toxicity realtes to effects on the ventricle, especially in prolonging the QT interval and causing torsades de pointes. Amiodarone, an agent with multiple antiarrhythmic effects, is unique in its relative lack of proarrhythmia, although its non-cardiac toxicities limit its use. Some investigational agents are directed at multiple ion channels, or are designed to be analogs of amiodarone. The other line of investigation focuses on the antiarrhythmic action of agents that affect novel ion channel targets. Basic and early clinical studies show promise for drugs that provide atrial antiarrhythmic effects without ventricular proarrhythmia by affecting the atrium preferentially or selectively (inhibiting the ITO and IKur currents, respectively). Future drugs may possess preferential effects on the remodeled atrium (and as such would be selective for patients with atrial fibrillation). It is hoped that efforts to develop new drugs, including those with preferential effects on the atrium, will provide therapy with greater efficacy and safety.
Item and Scale Information Functions for the Successive Intervals Rasch Model

Simulated data were used to investigate systematically the impact of various characteristics of the threshold values (number, symmetry, and distance between adjacent threshold values) and of the delta values on the distribution of item information in the successive intervals Rasch model. The results revealed that the shift in the peak of the information function away from the scale value of an item depended on the degree of asymmetry of the threshold values and the magnitude of the delta value of the item. The implications of the findings for computerized adaptive attitude measurement are discussed.
Learning to navigate in a virtual world using optic flow and stereo disparity signals

Navigating in a complex world is challenging in that the rich, real environment provides a very large number of sensory states that can immediately precede a collision. Biological organisms such as rodents are able to solve this problem, effortlessly navigating in closed spaces by encoding in neural representations distance toward walls or obstacles for a given direction. This paper presents a method that can be used by virtual (simulated) or robotic agents, which uses states similar to neural representations to learn collision avoidance. Unlike other approaches, our reinforcement learning approach uses a small number of states defined by discretized distances along three constant directions. These distances are estimated either from optic flow or binocular stereo information. Parameterized templates for optic flow or disparity information are compared against the input flow or input disparity to estimate these distances. Simulations in a virtual environment show learning of collision avoidance. Our results show that learning with only stereo information is superior to learning with only optic flow information. Our work motivates the usage of abstract state descriptions for the learning of visual navigation. Future work will focus on the fusion of optic flow and stereo information, and transferring these models to robotic platforms.
Orientation of enzymic domains in tryptophan synthase of Neurospora crassa: an immunoblot analysis of TRP3 mutant products.

Extracts of 52 TRP3 mutants of Neurospora crassa were tested for the presence of serologically cross-reacting material by the method of electrophoretic blot analysis. The test antigen was obtained by excision of lightly stained bands of denatured pure tryptophan synthase after SDS-polyacrylamide gel electrophoresis. Rabbit antisera raised against this antigen neutralized and precipitated native tryptophan synthase. Of the 52 strains, 19 exhibited banding patterns similar to wild type on electrophoretic blots, 25 strains gave no apparent bands, and 8 strains showed unique banding patterns. This evidence and related genetic fine structure mapping data indicate that strains exhibiting banding patterns similar to wild type carry missense mutations. Strains which did not exhibit any obvious bands may have resulted from certain kinds of missense or nonsense mutations or from frameshift mutations or extended deletions. Strains exhibiting unique banding patterns on electrophoretic blots were interpreted as carrying chain-terminating mutations or deletions. Genetic fine structure mapping data place the mutant lesions of these strains in a linear order corresponding to the apparent molecular weights of the crossreacting protein fragments which they exhibit. The direction of transcription and translation of the TRP3 locus in Neurospora was inferred from these relationships. The apparent organization of the Neurospora TRP3 gene is consistent with that ascribed to the Saccharomyces TRP5 system and suggests that the N-terminal portion of the protein corresponds to the “A” protein of the Escherichia coli system and that the C-terminal portion of the protein corresponds to the “B” protein of the bacterial system.
A model for courseware development in psychology

Many behavioral scientists are aware of the advantages of a systematic approach to research and the development of software used in research. However, coordinated and systematic efforts to develop instructional materials in the behavioral sciences are relatively rare. This paper and the symposium of which it is a part describe a systematic effort funded by FIPSE to assess the needs for microcomputer tools and courseware in the undergraduate curriculum in psychology and to stimulate the development of high-quality materials. The conceptual bases for development of materials are vertical and horizontal integration-the development of courseware that spans the curriculum from introductory to advanced, specialized, courses, and the systematic use of materials within a course and across courses and subject areas. The activities of the project, as well as implications for other computer-based development projects, are discussed.
Robustness of archaeal populations in anaerobic co-digestion of dairy and poultry wastes

The objective of this study is to investigate the responses of methanogen populations to poultry waste addition by comparing the archaeal microbial populations in continuous anaerobic digesters with or without the addition of poultry waste as a co-substrate. Poultry waste was characterized as an organic/nitrogen-rich substrate for anaerobic digestion. Supplementing dilute dairy waste with poultry waste for anaerobic co-digestion to increase organic loading rate by 50% resulted in improved biogas production. Elevated ammonia derived from poultry waste did not lead to process inhibition at the organic loadings tested, demonstrating the feasibility of the anaerobic co-digestion of dairy and poultry wastes for improved treatment efficiency. The stability of the anaerobic co-digestion process was linked to the robust archaeal microbial community, which remained mostly unchanged in community structure following increases in organic loading and ammonia levels. Surprisingly, Crenarchaeota archaeal populations, instead of the Euryarchaeota methanogens, dominated the archaeal communities in the anaerobic digesters. The ecological functions of these abundant non-methanogen archaeal populations in anaerobic digestion remain to be identified.
The evolution of the common law: Legal development in Kenya and India

Abstract Recent cross-national studies of the institutional prerequisites of economic growth have identified common law systems as superior to those of civil law. The assumption is that all common law systems share a similarity of structure and law which creates an environment facilitating investment and contract enforcement. Yet, due to its evolutionary nature, common law is not everywhere the same, nor is the historical development of the common law similar in all countries. This paper makes this point by examining the political development of common law in India and Kenya, in order to compare their legal institutions and histories. Both of these countries adopted common law through its transplantation in the context of colonial domination rather than organically. The paper concludes that the two countries, though sharing the common law, had very different colonial experiences of legal development. Moreover, once Kenya and India achieved independence, political circumstances affected institutional devel...
Developing a comprehensive communication strategy to meet the needs of various stakeholder groups

Instructional and Research Technology Services (IRTS) at Indiana State University, through input from various stakeholder groups, has developed a comprehensive communication strategy for the Office of Information Technology (OIT). This plan covers communications to internal OIT staff, Indiana State staff, faculty, and students, as well as the general public. This plan created mechanisms to market OIT services, publicize OIT accomplishments, support other OIT units in their documentation of operational services, and to support the CIO's goal of enhancing customer service. In working on this strategy IRTS has been identifying and implementing best practices for communicating to its campus constituencies.The plan was based around three communications and marketing channels (print, electronic, and events/presentations). During the first year of the plan IRTS has created and distributed:The ISU Technology Profile - The information for this document was collected from various units across campus. It details, in charts and graphs, the resources, personnel, and outputs from OIT.Technology @ Indiana State: Faculty/Staff and Student Guides - These guides provide basic, yet useful, information to help the university community to use the tremendous technology resources available at Indiana State.Sycamore.Net Newsletter - This bi-monthly newsletter was created to enhance communication across campus by informing the campus of technology-related activities and providing information to augment users' technology experience.Technology Infomercials - Short, 30-second to 3-minute, videos highlighting information technology services on campus.Other Communication Vehicles - Brochures, ads in the campus student newspaper, updated OIT Web site, scholarly publication centered on faculty use of technology, creation of a campus wide message board system, documentation of new initiatives, and monthly meetings with the local media to publicize new project and initiatives.
Oxidation-reduction potential dependence of low-temperature photoreactions of chloroplast photosystem. II.

Abstract The light-induced free-radical signal of Photosystem II (observed after illumination at 77 °K) has been studied in chloroplasts as a function of the oxidation-reduction potential established prior to freezing. The intensity of the light-induced signal is unchanged in the potential region of +590 mV to +760 mV. At higher potential (+850 mV), there is a 30% decrease in signal intensity. The light-induced signal decreases to zero in the low-potential region, with a midpoint potential of +475 mV. These results are considered in terms of a Photosystem II reaction-center complex in which the light-induced free-radical signal arises from the oxidized form of the reaction-center chlorophyll, and this chlorophyll molecule is capable of being reduced at liquid-nitrogen temperature by a secondary electron donor which has a midpoint oxidation-reduction potential of +475 mV.
Serum albumin beads: an injectable, biodegradable system for the sustained release of drugs

Biologically active compounds were entrapped in cross-linked serum albumin microbeads. Injection of these drug-impregnated beads into rabbits produced no adverse immunological reactions. Sustained release (20 days) of progesterone was demonstrated in vivo.
Interference of biocytin with opioid-evoked hyperpolarization and membrane properties of rat spinal substantia gelatinosa neurons.

Abstract In our laboratory, preliminary whole-cell, tight seal recordings of rat spinal substantia gelatinosa neurons including biocytin in the patch pipette yielded a significantly smaller proportion of neurons hyperpolarized by selective opioid agonists compared with recordings without biocytin. Therefore, we investigated the effects of biocytin inclusion on opioid responses and other membrane properties during whole-cell, tight seal recordings of these neurons. The percentage of neurons hyperpolarized by μ-, δ1-, and κ-selective opioids was significantly reduced when 1% but not ≤0.2% biocytin was included in the recording pipette, compared with neurons recorded without biocytin. However, a significantly higher proportion of neurons fired spontaneous action potentials with either 0.05–0.2 or 1% biocytin compared to no biocytin. Resting membrane potential, input impedance and the proportion of neurons displaying transient outward rectification were each significantly altered for neurons recorded with 1% but not 0.05–0.2% biocytin. These effects may be due to a relatively specific blockade of diverse potassium channel types. Because efficient labeling can be achieved with 0.1% biocytin with whole-cell recording, higher concentrations are contraindicated.
Noninvasive fluorescence-based instrumentation for cancer and precancer detection and screening

In this paper, we review our research in the use of UV and visible native fluorescence emission and excitation spectroscopy for the detection of cancer and precancer. We discuss some of the spectroscopic signatures indicative of the presence of cancer and precancer. We describe three generations of instruments being developed to extent optical biopsy technology into the clinical environment as both a screening tool and as a diagnostic aide suitable for gynecological, gastro-intestinal tract, oral cavity, brain and breast.
Abnormal collagen in cultures of fibroblasts from human beings with diabetes mellitus

Abstract Synthesis of collagen by fibroblasts from diabetic human beings was investigated to determine if abnormal synthesis might be responsible for an apparent acceleration of collagen aging observed previously in diabetics. Increased material was synthesized by cells from diabetics, and the material was abnormal in that it contained a very high molecular weight material and lacked a presumed procollagen dimer. Alpha chains did not appear altered. It is suggested that cultures of cells from diabetics yield a non-helical peptide of procollagen that contains abnormal reducible cross links and lacks normal non-reducible cross links.
Flavonoid data and populational observations in support of hybrid status for Populus acuminata

Flavonoid distribution and populational composition at the collection sites of several samples of Populus acuminata strongly suggest that this taxon is an inter-sectional hybrid between P. angustifolia, sect. Tacamahaca and any one of two or three different species of the section Aigeiros, when the entire range is considered. In the vicinity of the type locality, the Aigeiros parent is P. sargentii. Within any population, foliage of trees of P. acuminata is characterized by morphological intermediacy and an essentially additive flavonoid profile, as compared to the two parental taxa present. In habit the trees resemble those of P. sargentii, and habitats at the collection sites were found to be somewhat intermediate. Fifteen flavonoid compounds were consistently present in samples of the putative hybrid. Twelve of these had diagnostic value because they were absent in one of the parental species. One compound, apigenin 7-O-diglucoside, was found only in P. acuminata. In part, our identifications correspond to compounds reported by Crawford in a morphological and chemical study of P. acuminiata.
Registration For Health Care In City Clinics

Outpatient departments - as Franz Goldmann pointed out two decades ago - have been primarily a large-city development. In his broader discussion of the principles and problems of public medical care, Goldmann treats the Outpatient Department (OPD) as a type of clinic organization which has its own distinct history. In the current terminology of many New York City dwellers the term "Clinic" is commonly understood to refer to the particular places under study here; however, this type of organization is not unique to one locale. (Since the term "clinic" generally refers both to the whole outpatient department and to the medical specialties within any one department, the term will be capitalized when the reference is to its broader sense; lower case will be used when referring to the clinics as subunits.)
Relaxation of infinite-dimensional variational and control problems with state constraints

One examines the question of relaxability of infinite dimensional variational problems with state constraints. One considers systems governed by multivalued evolution equations («trajectory problem»). One starts with a new, general existence result for such inclusions with nonconvex valued orientor field. Then one proves a relaxation result. Using perturbed and penalized versions of the original variational problem, one shows that relaxability for the system is equivalent to a well-posedness notion that one calls «strong calmness». The same analysis is also carried on for semilinear systems. Finally one works an example of a distributed parameter control system
Individual- and group-directed leader behavior descriptions.

Relationships among individual- and group-directed measures of leader behavior descriptions and five variables were examined with an explicit consideration of multiple levels of analysis. In a sample of law enforcement personnel, results indicated that supervisor control and satisfaction with rewards were associated with individual- and group-directed measures of initiating structure based on differences between groups, but not within groups; role ambiguity and effort were associated with individual- and group-directed measures of consideration based on differences between groups, but not within groups; and satisfaction with supervisor was associated with individual- and group-directed measures of initiating structure and of consideration based on individual differences. Thus, different forms of measures (individual- or group-directed) of leader behavior descriptions were correlated with other variables based on different levels of analysis.
Synchronization of perturbed non-linear Hamiltonians

We propose a new method based on Lie transformations for simplifying perturbed Hamil- tonians in one degree of freedom. The method is most useful when the unperturbed part has solutions in non-elementary functions. A non-canonical Lie transformation is used to eliminate terms from the perturbation that are not of the same form as those in the main part. The system is thus transformed into a modified version of the principal part. In conjunction with a time transformation, the procedure synchronizes the motions of the perturbed system onto those of the unperturbed part. A specific algorithm is given for systems whose principal part consists of a kinetic energy plus an arbitrary potential which is polynomial in the coordinate; the perturbation applied to the principal part is a polynomial in the coordinate and possibly the momentum. We demonstrate the strategy by applying it in detail to a perturbed Duffing system. Our procedure allows us to avoid treating the system as a perturbed harmonic oscillator. In contrast to a canonical simplification, our method involves only polynomial manipulations in two variables. Only after the change of time do we start manipulating elliptic functions in an exhaustive discussion of the flows.
From Transcription to mRNA: PAF Provides a New Path

Two new studies (Penheiter et al. [2005] and Sheldon et al. [2005], this issue of Molecular Cell) reveal a novel connection between transcription and pre-mRNA processing: the Paf1 elongation complex is involved in the 3′ end formation of polyadenylated and nonpolyadenylated RNA polymerase II transcripts.
International volunteers' perceptions of intercultural competence

Abstract Although international volunteer sending organizations vary greatly, nearly all claim that volunteering will increase intercultural competence. Various theories of intercultural learning suggest, however, that cultural contact will only improve a volunteer's intercultural competence under certain conditions. The study collects self-reported responses from 291 volunteers who served in one of two service models that differ on multiple characteristics. This study isolates four key characteristics and employs a moderated multiple regression to test how these variations affect volunteers’ perceptions of intercultural competence. Findings suggest that that service duration, cultural immersion, guided reflection, and contact reciprocity are all positively associated with intercultural competence. In addition, guided reflection appears to moderate the relationship between duration and intercultural competence. This study responds to the need for research on the effects of international volunteering across institutional models.
X-ray study of atomic correlations in Zn{sub 0.5}Cd{sub 0.5}Se{sub 0.5}Te{sub 0.5} epitaxial thin films

X-ray absorption fine-structure spectroscopy (XAFS) measurements have been performed at approximately 90 K to study the local structure of II-VI quaternary alloy ${\mathrm{Zn}}_{0.5}$${\mathrm{Cd}}_{0.5}$${\mathrm{Se}}_{0.5}$${\mathrm{Te}}_{0.5}$. Samples were grown by molecular beam epitaxy on (100) GaAs substrates, 4\ifmmode^\circ\else\textdegree\fi{} miscut towards the (111)B direction with a ZnTe buffer layer. The XAFS data indicate that there are more Zn-Se and Cd-Te bonds in the alloy than expected for a random arrangement. The results imply the formation of high-strain local structure and indicate that electronic pairing energies dominate over strain energy. These results are similar to the earlier observation of interlayer switching in ZnTe/CdSe superlattices. The preference of Zn-Se and Cd-Te bonding also implies a tendency to spontaneously form a composition-modulated microstructure.
Retinoic acid differentially regulates expression of surfactant-associated proteins in human fetal lung

Retinoic acid is known to play an essential role in maintaining the differentiation of a wide variety of epithelial cell types. However, its effects on the differentiation of lung alveolar epithelium have not been described. In the present study, we examined the effects of retinoic acid on the differentiation of human fetal lung tissue maintained in vitro. Human fetal lung explants were cultured in serum-free medium for 6 days in the absence or presence of all-trans retinoic acid at concentrations from 0.3 nM to 3 microM. Explant content of the surfactant-associated protein SP-A was measured using a specific enzyme-linked immunosorbent assay. Retinoic acid reduced SP-A protein levels in a concentration-dependent manner [analysis of variance (ANOVA), P < 0.01]. To evaluate possible cytotoxic effects of retinoic acid, culture media were assayed for lactate dehydrogenase (LDH), a cytoplasmic enzyme. LDH levels in media from retinoic acid-treated explants were not significantly different than LDH levels in media from control explants, indicating that retinoic acid is not cytotoxic in human fetal lung explants. Changes in messenger RNA (mRNA) levels for surfactant-associated proteins SP-A, SP-B, and SP-C were measured by Northern blot analysis. Retinoic acid reduced SP-A mRNA levels in a concentration-dependent manner (ANOVA, P < 0.02) and reduced SP-C mRNA levels at 3 microM. In contrast, retinoic acid increased SP-B mRNA levels in a concentration-dependent manner (ANOVA, P < 0.03). Morphometric analysis showed that retinoic acid decreased epithelial volume density in the explants by approximately 17% and increased connective tissue volume density by approximately 20% when compared to dimethyl sulfoxide vehicle controls. These data indicate that retinoic acid regulates type II cell surfactant protein gene expression in human fetal lung tissue.
Witchcraft Practices and Psychocultural Therapy with Urban U. S. Families

Reports of an increase in witchcraft manifestations in the United States have given rise to the need for mental health staffs who can understand witchcraft behavior, beliefs, practices, and some of the dynamic factors influencing the occurrence of this phenomenon. Currently, witchcraft victims are being admitted to mental health clinics and hospitals, but often the staff may not be aware of witchcraft behavior or its significance, and may not know how to help the victims. Consequently, witchcraft victims may not be helped at all or may receive treatment which aggravates the condition. Witchcraft as an expression of psychological, social-cultural norm stresses must be understood within the victim's cultural context. This paper describes an empirically derived psychocultural framework which was used as a guide in helping the witchcraft victims.
Subset Selection Toward Optimizing the Best Performance at a Second Stage

In the search for the best of n candidates, two-stage procedures of the following type are in common use. In a first stage, weak candidates are removed, and the subset of promising candidates is then further examined. At a second stage, the best of the candidates in the subset is selected. In this article, optimization is not aimed at the parameter with largest value but rather at the best performance of the selected candidates at Stage 2. Under a normal model, a new procedure based on posterior percentiles is derived using a Bayes approach, where nonsymmetric normal (proper and improper) priors are applied. Comparisons are made with two other procedures frequently used in selection decisions. The three procedures and their performances are illustrated with data from a recent recruitment process at a Midwestern university.
Why be normal

Suppose we have an algebra A of quantum observables. What virtues must a function ω:A→C exhibit in order to qualify as a quantum state? One virtue familiar from density operator states is countable additivity: a density operator ρ on H determines a countably additive probability distribution over H's closed subspaces; such a probability distribution corresponds to what's known as a normal state on the von Neumann algebra B(H) of bounded operators on the Hilbert space. This essay investigates the virtue of normality, by presenting a number of physical situations and/or interpretive impulses that might tempt one to acknowledge states that are not normal, and by adducing reasons to resist these temptations.