cssi/SciSciGPT-SciSciNet huggingface dataset:
Energetics and Structures of Gas Phase Ions: Macromolecules, Clusters and Ligated Transition Metals

In this paper a number of methods for determining thermochemical data for gas phase ions are described. Of most importance are ion equilibrium measurements where emphasis is placed on the differences in our work from earlier studies. Most of the paper is devoted to novel applications. These emphasize transition metal centers, the roles ligands play in activating them, and the very subtle interplay between the nearly degenerate s and d orbitals. A case study of sequential ligation by dihydrogen of the entire first transition metal series is given. Generally the first solvation sphere closes at n = 6 but interesting exceptions are noted. High level ab initio calculations are done on each system allowing structural information and details of the bonding to be obtained. Other systems discussed include a few second row metals, the role of the Cp ligand in activating Co+ and the discussion of a novel cluster assisted σ-bond activation scheme. The paper concludes with a demonstration that the structurally important ion chromatography technique can be used to extract thermochemical information on macromolecules under favorable conditions.
Dilational Response of Voided Polycrystals

Finite-element (FE) cell model computations have been used to gain insights into the ductile response of porous polycrystals. Generally, the behavior of the matrix is described by a J 2-plasticity model. In this article, we present a new computational approach to FE cell models for porous polycrystals deforming by slip based on crystal plasticity. The cell provides the homogenized dilational response, where the constitutive response of every integration point is based on a single-crystal visco-plasticity law. The calculations are performed for a body-centered cubic polycrystal with random texture. Axisymmetric tensile and compressive loadings are imposed corresponding to the fixed values of the stress triaxiality and to two possible values of the Lode parameter. The resulting numerical yield points are compared with those obtained using a J 2-FE cell and an analytical model. The predictions confirm the combined effects of the mean stress and third-invariant on yielding recently revealed by the analytical model.
Snow depth, soil temperature and plant–herbivore interactions mediate plant response to climate change

Northern forest ecosystems are projected to experience warmer growing seasons, as well as winters with reduced snowpack depth and duration. Reduced snowpack will expose soils to cold winter air and lead to increased frequency of freeze-thaw cycles. The interactions between warmer soils in the growing season and colder soils in winter may have important implications for the phenology, productivity and nutrient content of forest plants. We conducted an experiment at Hubbard Brook Experimental Forest, NH, USA, to examine the effects of growing season warming, reduced depth and duration of winter snowpack, as well as increased frequency of soil freeze-thaw cycles on sugar maple (Acer saccharum) and red maple (Acer rubrum) saplings. We examined the direct effects of soil temperatures on plant root health, timing of leaf-out, foliar nitrogen, rates of photosynthesis and growth, as well as the indirect effects of snowpack reduction on herbivory on plant stems. A smaller winter snowpack and increased frequency of soil freeze-thaw cycles in winter led to increased root damage and delayed leaf-out for maple saplings. Snowpack reduction decreased rates of stem herbivory in winter, indicating that alleviation of above-ground stem damage in winters with reduced snowpack may offset the root damage incurred from successive soil freeze-thaw cycles in winters with low snowpack. Synthesis. By examining the response of two dominant tree species to simulated climate change in both the growing season and winter, we find that plant responses are mediated through a combination of changes in soil temperature and plant–herbivore interactions that differentially affect above- and below-ground plant components. These results highlight the feedbacks between trophic levels that shape forest function and demonstrate the need for considering climate change across seasons in global change experiments to determine how forest function may change in the future.
Effect of support structures on Ti-6Al-4V overhang parts fabricated by powder bed fusion electron beam additive manufacturing

Abstract The effects of the two support structures, thin-wall tooth contact (TC) and solid-gap (SG), on the Ti-6Al-4V parts fabricated by powder bed fusion electron beam additive manufacturing were investigated. In the Y-plane of the overhang, equiaxed β′ microstructure formed initially and gradually grew into a wider columnar structure with its width about 3 times of that iRn the solid section. Fine α/α′ and β phases were identified within the β′ grains, in which the content of α′ increases from the bottom to the top of the part and α/α′ phase presents strong textures of 0 0 0 1 and 1 1 2 ¯ 0 parallel to the build-direction. In addition, more defects were observed in the overhang than the solid, especially at the interface between the solid and the overhang sections which also induced the stress concentration. Compressive residual stresses were revealed in the parts with some points showing minor tensile residual stresses. Compared to the SG part, the TC part had a lower Vickers hardness. The solid part under the SG part acted as a heat sink and enhanced heat dissipation during the manufacturing process, which affected the thermal gradient and improved the microstructures and mechanical properties in the overhang. The teeth in the TC part did limit the occurrence of the wrapping phenomenon. Taking advantages of the two designs, a new support design, SG support with teeth at the tip-end of overhang, is recommended.
A Single, Post-ACTH Cortisol Measurement to Screen for Adrenal Insufficiency in the Hospitalized Patient.

BACKGROUND Cosyntropin stimulation testing (CST) is used to screen patients for adrenal insufficiency (AI). Traditionally, CST includes baseline cortisol concentration, the administration of cosyntropin, and cortisol concentration at 30 and 60 minutes poststimulation. There is debate surrounding the utility of testing and cut-off points for concentrations at each time point. OBJECTIVE To determine if a single cortisol measurement at 30 or 60 minutes could replace the traditional approach. DESIGN looked retrospectively at inpatients who underwent standard, high-dose CST (n = 702) and evaluated the number of patients who would screen positive for AI by using a single time point (30 or 60 minutes) compared with the traditional CST. SETTING A tertiary-care, academic medical center. PATIENTS Hospital inpatients present between January 2012 and September 2013. RESULTS Of tests, 84.3% were normal, which was defined as at least 1 cortisol concentration of 18 mcg/dL or higher at any time after stimulation. The average 60-minute concentration was higher than the average 30-minute concentration (P < .001). A single 60-minute concentration is 100% concordant with the full CST in the intensive care unit (ICU) subgroup and 99.6% concordant in floor patients. A single 30-minute concentration is significantly less concordant, 91.9% and 86.9%, in the ICU and floor subgroups, respectively. CONCLUSIONS Overall, a single 60-minute cortisol concentration to screen for AI was 99.7% concordant with the traditional CST, and the positive percent agreement was 98%. Fewer false-positive screens would occur with a single 60-minute cortisol concentration compared with a single 30-minute concentration (P < .001). High-dose CST screening may safely be interpreted with single 60-minute poststimulation cortisol serum concentrations.
Mature weight, maturation rate, maternal performance and their interrelationships in purebred and crossbred cows of angus and milking shorthorn parentage.

Mature weight, maturation rate and lifetime maternal performance, through a maximum of seven calving seasons, were analyzed for 182 cows of Angus (A) and Milking Shorthorn (S) breeds and the two reciprocal crossbred groups. Mature weight and rate of maturation were estimated for the three-parameter growth curve described by Brody. Estimates derived for mature weight (kilograms), both unadjusted and adjusted for cow condition, were, respectively: Angus, 421, 407; Shorthorn, 409, 459; A x S, 448, 455 and S x A, 440, 441 (approximate standard error, 8 kg). Estimates for the maturation rate parameter were, respectively: Angus, 5.8, 6.3; Shorthorn, 6.6, 5.4, A x S, 6.2, 6.1 and S x A, 5.9, 6.1%/month (approximate SE, .3%/month). Heterosis for mature weight was 3 to 7% (28 +/- 8 and 15 +/- 6 kg, respectively). No heterosis was observed for the maturation rate parameter. Birth weight (.048 +/- .025 kg/kg) and weaning weight (.142 +/- .044 kg/kg) of the first calves were positively related with mature size of the dam. Weaning weights of first calves increased with increasing rate of maturation of the dams (3.6 +/- 1.5 kg/percentage/month) while birth weights remained unchanged. Under the culling criteria used in this study, the number of calves produced by a cow in her lifetime decreased (-.007 +/- .003 calves/kg) with increasing mature weight, while average weaning weight of the calves increased (.132 +/- .03 kg/kg). Total weight weaned, years in the herd and weight weaned per year tended to decrease (P greater than .05) with increasing mature weight of dam, but not significantly. Positive heterosis was expressed for all lifetime cow productivity characters, with crossbred cows weaning 22% (230 +/- 57 kg) more calf weight in their lifetime.
Fat Is a Social Justice Issue, Too:

Empirical evidence continues to show that like other historically marginalized groups, fat people experience discrimination in employment, education, the media, politics, interpersonal relationship...
Direct triplet sensitization of oligothiophene by quantum dots.

Effective sensitization of triplet states is essential to many applications, including triplet–triplet annihilation based photon upconversion schemes. This work demonstrates successful triplet sensitization of a CdSe quantum dot (QD)–bound oligothiophene carboxylic acid (T6). Transient absorption spectroscopy provides direct evidence of Dexter-type triplet energy transfer from the QD to the acceptor without populating the singlet excited state or charge transfer intermediates. Analysis of T6 concentration dependent triplet formation kinetics shows that the intrinsic triplet energy transfer rate in 1 : 1 QD–T6 complexes is 0.077 ns−1 and the apparent transfer rate and efficiency can be improved by increasing the acceptor binding strength. This work demonstrates a new class of triplet acceptor molecules for QD-based upconversion systems that are more stable and tunable than the extensively studied polyacenes.
Self-perception of aging among HIV-positive and HIV-negative participants in the Multicenter AIDS Cohort Study

Self-perception of aging is an important predictor of quality of life. Therefore, we sought to examine self-perceptions of aging (age discrepancy and aging satisfaction) between HIV-positive and HIV-negative men in the Multicenter AIDS Cohort Study (MACS). We included 835 HIV-negative and 784 HIV-positive men aged 50 years and older who had completed a survey about age discrepancy and aging satisfaction from the "Attitude toward own aging" subscale of the Philadelphia Geriatric Center Morale scale. Multinomial generalized logit models were generated to assess self-perception of aging by HIV-status. Most of the participants self-identified as white, former smokers, and had completed high school. HIV-positive individuals reported higher prevalence of comorbidities than HIV-negative individuals. After adjusting for covariates, positive age discrepancy (older subjective age) was positively associated with being HIV-positive and having less than a high school education, depressive symptoms, diabetes, and medium and low aging satisfaction. Low aging satisfaction was associated with being a current and former smoker and having depressive symptoms, diabetes, and no age and positive age discrepancy. Being black had decreased odds of low aging satisfaction. These findings should inform health care professionals to promote positive views of aging in the assessment and management of HIV, depression, and diabetes.
Omega-3 Fatty Acids and Gut Microbiota: A Reciprocal Interaction in Nonalcoholic Fatty Liver Disease.

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease characterized with the spectrum of hepatic steatosis, inflammation, and fibrosis. The etiology of NAFLD remains incompletely understood. Numerous studies have implied that the gut microbiota (GM) is involved in the development of NAFLD, as it particularly mediating the interaction between nutrient intake and the gut–liver function. Meanwhile, the omega-3 and omega-6 polyunsaturated fatty acids (n-3/n-6 PUFA) as essential fatty acids have been linked to NAFLD. Increasing studies in the past decades have indicated that there is a reciprocal interaction between GM and n-3/n-6 PUFA, which may be underlying at least in part, the pathogenesis of NAFLD. In this review, we will discuss: (1) How GM is linked to NAFLD by interacting with various nutrients; (2) How imbalanced dietary n-3/n-6 PUFA is linked to NAFLD; (3) How n-3/n-6 PUFA may affect the GM balance, leading to altered nutrients release to the liver; and (4) How GM may modify ingested n-3/n-6 PUFA and alter their absorption, bioavailability, and biotransformation.
Effects of group activity schedule training on preference for social play among children with autism

Abstract Group activity schedules have been used to increase social engagement in children with autism spectrum disorders, but it is not known whether these experiences increase children’s preference for such interactions outside of therapy sessions or with different partners. This study evaluated the effects of training through the use of group activity schedules on children’s social responding in a concurrent choice paradigm. Four children with autism were given choices between social and solitary play prior to and following training in the use of group activity schedules. Prior to training, all participants predominantly chose to engage in solitary play. Subsequent to training, four out of four participants demonstrated increased preference for social play. For children with autism, exposure to structured social activities with systematically decreasing adult support may facilitate social skill development as well as preference for social interaction.
Charge Transfer Excitons at van der Waals Interfaces

The van der Waals interfaces of molecular donor/acceptor or graphene-like two-dimensional (2D) semiconductors are central to concepts and emerging technologies of light-electricity interconversion. Examples include, among others, solar cells, photodetectors, and light emitting diodes. A salient feature in both types of van der Waals interfaces is the poorly screened Coulomb potential that can give rise to bound electron–hole pairs across the interface, i.e., charge transfer (CT) or interlayer excitons. Here we address common features of CT excitons at both types of interfaces. We emphasize the competition between localization and delocalization in ensuring efficient charge separation. At the molecular donor/acceptor interface, electronic delocalization in real space can dictate charge carrier separation. In contrast, at the 2D semiconductor heterojunction, delocalization in momentum space due to strong exciton binding may assist in parallel momentum conservation in CT exciton formation.
Closed Incision Negative Pressure Wound Therapy for Elective Hip and Knee Arthroplasty: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Abstract Background Persistent wound drainage after total joint arthroplasty (TJA) increases the risk of surgical site infections (SSIs). Closed incision negative pressure wound therapy (ciNPWT) decreases infections in traumatic wounds, but evidence for its use after elective TJA is limited. The purpose of this meta-analysis of level I studies is to determine the effect of ciNPWT on risk of SSI and wound complications following TJA. Methods MEDLINE, EMBASE, CINAHL, and Cochrane Library were searched for randomized controlled trials comparing ciNPWT vs standard dressings after total hip (THA) and total knee arthroplasty (TKA). Studies exclusively involving THA for femoral neck fractures were excluded. Risk of SSI and noninfectious wound complications (blisters, seroma, hematoma, persistent drainage, dehiscence, and wound edge necrosis) following TJA were analyzed. Results SSI risk was lower with ciNPWT compared to standard dressings (3.4% vs 7%; relative risk [RR] 0.48, P = .007), specifically in revision THA and TKA (4.1% vs 10.5%; RR 0.41, P = .03). ciNPWT increased the noninfectious complication risk after primary TKA (RR 4.71, P Conclusion ciNPWT decreases SSI risk compared to standard dressings after revision TJA, but not primary TJA. ciNPWT is associated with >12-fold increased risk of wound blistering after primary TKA. ciNPWT plays a role in revision TJA management, but additional randomized controlled trials with uniform wound assessment methods must be performed to sufficiently power findings and draw conclusions on the use of ciNPWT after primary TJA.
To Flip or Not to Flip: Learning Style Preferences among Millennial Physician Assistant Students.

Introduction Presenting material in a manner that is most palatable to students is important to improve the learning process. We evaluated the efficacy of different teaching styles including the flipped classroom and assessed the learning style preferences of a cohort of medical learners in a preclinical obstetrics and gynecology course. Methods We conducted three teaching sessions with 35 physician assistant students. A different teaching style was implemented for each session including a traditional lecture with interactive learning technology augmentation, a flipped classroom, and a hybrid approach incorporating lecture and group work. Students were surveyed using a Likert scale regarding the efficacy of the format, clinical relevance of the material, and their learning preference for future sessions. Results Students rated the traditional approach as the most effective, most relevant, and most preferred method. Students preferred the flipped classroom least, but they rated it as slightly more effective and relevant than the hybrid approach. Conclusion The teaching style of various coursework including the preclinical obstetrics and gynecology curriculum may not need to be altered for millennial learners. This study showed the flipped classroom was the least favored teaching style and that there was a marked preference by students for a more traditional didactic lecture.
Mosquito Empires: Ecology and War in the Greater Caribbean, 1620–1914

Part I. Setting the Scene: 1. The argument: mosquito determinism and its limits 2. Atlantic empires and Caribbean ecology 3. Deadly fevers, deadly doctors Part II. Imperial Mosquitoes: 4. From Recife to Kourou: yellow fever takes hold, 1620-1764 5. Cartagena and Havana: yellow fever rampant Part III. Revolutionary Mosquitoes: 6. Lord Cornwallis vs anopheles quadrimaculatus, 1780-1 7. Revolutionary fevers: Haiti, New Granada, and Cuba, 1790-1898 8. Epilogue: vector and virus vanquished.
Allocation of Capital under the Test of Rapidly Changing Economic Conditions

The Great Depression is a unique historical episode, so shocking that at least the contemporaries became determined not to allow its recurrence. The experience is valuable, however, in that it permits us to observe how major changes in the economic structure affect a country’s past commitment of resources to specific uses. After all, all investment decisions usually allocate capital for the duration of several years.
Studies on Sperm Motility by Laser-Light Scattering

Measurement of sperm motility has received considerable attention of many investigators since the earliest observations of Leeuwenhoek. However, sperm motility has often been judged subjectively by an individual. Therefore, a suitable definition for the measurement of sperm motility continues to confuse the observer. Many methods of measurement have been developed in recent years (1,2). Essentially, these techniques can be divided into two categories depending upon the objectives of the study, which may be associated with the mechanism of flagellation of single cells or may be concerned with the evaluation of relevant statistical parameters which describe the quality of sperm motility. In the studies of effects of exogenous factors on sperm motility and clinical evaluations of semen quality, the microphoto-graphic technique for studying single cells becomes cumbersome due to its inherent disadvantage of being time-consuming. This paper summarizes some of our recent studies of sperm motility by laser-light scattering. Results of these measurements show that this simple and objective method has considerable potential for both basic research and clinical use in biomedical studies.
The Education of an Engineer (A Continuing Story)

The education of an engineer is and must be a continuing process. In addition to the basic knowledge, there are certain skills and philosophies also necessary for progression toward and attainment of the title of engineer. These are effective communication; interpersonal relations; a feel for the lessons of the past; an understanding of economics and politics; a code of ethics for personal and professional development; and a committment to society. The quest for these qualities is an education which is never finished.
Physiology of the Bdellovibrios

Publisher Summary This chapter discusses the physiology of the bdellovibrios. Additional cultures of this unusual organism were isolated in California, it was further characterized, and it was named “Bdellovihrio hucteriovorw.” Bdellovibrio can be distinguished from bacteriophages by the kinetics of development of the plaques on host lawns. Bdellovibrio plaques become in lawns only after 2–4 days and then enlarge progressively with continued incubation up to six days. Bdellovibrio has been characterized by its being an actively motile, rather small, vibroid bacterium, which attaches to the bacterial host cell. This chapter also deals with the treatments that emphasize the physiology and biochemistry of the bdellovibrios, which stresses the morphological, ecological, and taxonomic aspects of the burgeoning bdellovibrios.
Biological Implications of Global Marine Pollution

The sea is discussed as an excellent source of animal protein, the lack of which contributes to malnutrition of large numbers of the human population. Although the sea produces large amounts of vegetable material, its harvest is unrealistic because it is so sparsely distributed. Consequently, the land must continue to produce the energy rich plant materials in the human diet. Pollution has already limited our harvest of seafood in estuaries, and the remaining areas, suitable for marine life, must be protected from additional pollution if we are to maintain and increase our harvest of protein from the sea. The potential supply, and its limitation, are briefly discussed and it is suggested that development of modern aquaculture would be desirable, in addition to the search for and exploitation of additional natural populations.
Spatial and temporal distributions of bromoform and dibromomethane in the Atlantic Ocean and their relationship with photosynthetic biomass

[1] Atmospheric mixing ratios and seawater concentrations of bromoform (CHBr3), dibromomethane (CH2Br2), and other brominated very short-lived substances (BrVSLS) were measured during five cruises from 1994 to 2010. These cruises were conducted over large latitudinal (62°N–60°S) and longitudinal transects (11°W–86°W) in the Atlantic Ocean. Elevated seawater concentrations of CHBr3 and CH2Br2 were often observed in regions where chlorophyll a concentrations were also elevated, which suggests biogeochemical processes associated with photosynthetic biomass may be related to CHBr3 and CH2Br2 production. Our results suggest that, at least in the open ocean, several phytoplankton taxa may contribute to the production of these trace gases. While observed correlations between CHBr3 and CH2Br2 in different regions are usually interpreted as common sources for these compounds, results in this study suggest different biogeochemical processes may contribute separately to the production of these trace gases. Heterotrophic bacterial abundance was significantly correlated with CH2Br2, but not with CHBr3, which suggests the biogeochemical processes associated with heterotrophic bacteria may be related to CH2Br2 in seawater but probably not to CHBr3. In general, the Atlantic Ocean is a net source for CHBr3 and CH2Br2, except for a few locations where these trace gases were undersaturated in seawater. Assuming fluxes measured in the Atlantic open ocean are globally representative, the resulting extrapolated, global open-ocean annual net sea-to-air fluxes calculated from data from the five cruises was estimated at 0.24–3.80 Gmol Br yr−1 for CHBr3 and 0.11–0.77 Gmol Br yr−1 for CH2Br2.
The Role of Prevalence Rates, Sensitivity, and Specificity in Assessment Accuracy: Rolling the Dice in Social Work Process

A little discussed issue for practitioners is the probability that a client actually has (or does not have) a disorder that he or she has been diagnosed as having (or not having). These probabilities depend upon the sensitivity and specificity of the assessment procedure used, and on the prevalence of the disorder among those seeking services. Probability theory is used in this article to demonstrate that in many, if not most cases, these probabilities will be quite low and that the likelihood of misdiagnosis will be high. The implications of these findings for assessment in social work practice are discussed.
Generating Efficient Code from Strictness Annotations

Normal order functional languages (NOFLs) offer conceptual simplicity, expressive power, and attractiveness for parallel execution. However, current implementations of NOFLs on conventional von Neumann machines are not competitive with those of imperative languages. The central reasons for this poor performance include the high control overhead (e.g. demand evaluation) and fine object code granularity (e.g. SKI combinators) used in most NOFL implementations. Strictness analysis gathers information that helps to overcome these inefficiencies through optimized compilation. We propose here a rule-based strategy for such compilation, working from a new textual representation for strictness analyzed source programs. This representation offers readability and ease of manipulation, while expressing all essential strictness information, including basic block structure and block dominance and disjunction relationships. The rules presented here show how to compile this intermediate form into optimized single processor G-machine code. In addition, this representation appears to be useful for a number of other execution methods, including interpretation, compilation into conventional Lisp with “promises”, and mapping into “supercombinators” for parallel architectures.
Reinvigorating Educational Malpractice Claims: A Representational Focus

For the past twenty tears, courts have faced a wide array of claims alleging misconduct by schools and their officials. These claims have involved diverse injuries, including: negligence in permitting functional illiterates to pass through the school system; negligent misdiagnosis of learning disabilities; and failure to deliver a promised package of educational skills and services.The judiciary has almost uniformly refused to allow recovery, in tort or otherwise, for such injuries. Some courts have conceded that, on the pleadings, a good case might be made out. Plaintiffs have nonetheless been turned away because of courts' related concerns with untrammeled litigation and with invading the province of the legislative and administrative bodies charged with operating the schools.This Article adopts the position that such a wastebasket approach to claims of educational injury is unjustified, and should be abandoned. The Article first attempts to sort out the various kinds of cases that courts have treated identically. It then proposes that a proper focus on the kinds of representations made in the educational setting, and plaintiff's sometimes forced reliance on those representations, can aid in the resolution of these disputes without justifying judicial fears. This emphasis on representation and reliance is justified through an examination of the role that representational notions play in other areas of tort law.Armed with the ordnance of representation, the Article then reconsiders a wide range of educational malpractice cases, suggesting approaches and solutions to problems that have thus far evaded principled analysis.
Variations of lipid-protein interactions in erythrocyte ghosts as a function of temperature and pH in physiological and non-physiological ranges. A study using a paramagnetic quenching of protein fluorescence by nitroxide lipid analogues.

Abstract 1. 1.|Incorporation of stearic acid nitroxides into erythrocyte ghosts markedly depresses the fluorescence of membrane protein tryptophan residues. 5-Nitroxide stearate quenches fluorescence more efficiently than 16-nitroxide stearate. Both compounds exhibit dynamic (diffusion-limited) quenching above 0.28 μmol/mg protein and static quenching at lower nitroxide protein ratios. Static quenching can be attributed to high affinity binding of nitroxide stearates by membrane protein. The dynamic phase represents distribution of the stearate analogues into a fluid lipid system. 2. 2.|Protein fluorophores accessible to quenching by a cholesterol analogue, androstane nitroxide, are saturated at low nitroxide/protein ratios ( mol/mg protein), without resolution of a static quenching phase. This suggests that sterols are segregated away from protein, probably in “clusters”. 3. 3.|Paramagnetic quenching by stearate nitroxides increases abruptly between 35 and 50 °C. This discontinuous enhancement of quenching by temperature is reversible up to 41 °C but irreversible at higher temperatures. The discontinuity is also diminished by lowering pH from 7.3 through 6.5 to 6.0. Quenching by androstane nitroxide increases linearly with temperature up to approx. 41 °C and then rises exponentially. We attribute the reversible quenching thermotropism detected by stearate derivatives to reversible, thermotropic unfolding and/or depolymerisation of membrane proteins. The irreversible phase, detected also by the sterol derivative can be attributed to non-reversible protein denaturation. 4. 4.|Paramagnetic quenching of membrane tryptophan fluorescence by stearate derivatives is minimal at approx. pH 7.1 (35 °C) and increases sharply at lower and higher pH values, suggesting that two categories of protein residues, titrating between pH 6 and 8, profoundly influence the association of fatty acyl chains and penetrating protein segments. Quenching by androstane nitroxide exhibits no significant variation between pH 6 and 8, consistent with other data indicating that erythrocyte membrane sterols are segregated from membrane proteins, probably in clusters. 5. 5.|Our new approach confirms previous suggestions of a boundary layer of lipid in close association with some proteins in erythrocyte membranes, as well as experiments indicating that the lipid status in this boundary layer depends on that state of membrane proteins. However, sterols appear to be largely excluded from this boundary domain. Our data further show that lipid-protein interactions in erythrocyte membranes can vary significantly with fluctuations of temperature and pH in the physiological range.
Plasmid-Associated Functions of a Stable Flac

Abstract Several functions associated with the stable plasmid, FlacS, have been examined. Our results indicate that the sex pili synthesized by Escherichia coli strains carrying FlacS are altered in some manner as evidenced by a very inefficient adsorption of male-specific phages. On the other hand, FlacS-mediated entry exclusion of related plasmids and plasmid incompatibility function(s) appear normal. The presence of covalently closed circular deoxyribonucleic acid in E. coli strains harboring FlacS indicates that it is an autonomously replicating plasmid. Based on β-galactosidase levels and the percentage of covalently closed circular deoxyribonucleic acid, it appears that the stability of the FlacS is not the result of multiple copies of this plasmid. FlacS appears larger than its precursor, Fts114lac, in sedimentation through alkaline sucrose gradients.
Effects of Staurosporine on Exocytosis and Endocytosis at Frog Motor Nerve Terminals

Observations of the dynamic staining and destaining of FM1-43 in frog motor nerve terminals (Henkel and Betz, 1995) suggested that staurosporine might shorten the interval between exocytosis and endocytosis, inducing a “kiss and run” mode of exocytosis and endocytosis. We tested this hypothesis by using FM1-43 imaging (to measure the time course of FM1-43 endocytosis), intracellular recording of evoked synaptic potentials (to measure acetylcholine release), and electron microscopy (to examine synaptic vesicle distribution). Staurosporine reduced FM1-43 uptake during but not after a tetanus, increased the speed of end plate potential (EPP) amplitude rundown, and greatly slowed the recovery from synaptic depression. Ultrastructural observations showed pronounced vesicle depletion near active zones after tetanic stimulation in staurosporine-treated preparations. These results suggest that staurosporine acted primarily to impair mobilization of synaptic vesicles during tetanic stimulation.
The Strange New World of the Quantum: Wave-Particle Dualism

When Heisenberg said of wave-particle dualism that it was as if a box were “full and empty at the same time,” he chose this Zen-like analogy not only because this strange dualism defies the normative Western sense of logical relationships; he was also suggesting that the allegedly “full” description of this reality in physical theory, wave mechanics, was “empty” in the sense that only the wave or particle aspect can be revealed in single acts of observation. Both aspects are never present in a single measurement, and the aspect that is apparent is a function of experimental choice. The new logic that describes this situation, developed by Niels Bohr, is known as the “logical framework of complementarity.”
A Bliss-Type Multiplier Rule for Constrained Variational Problems with Time Delay

Abstract This paper gives a Bliss-type multiplier rule for general constrained variational problems with time delay. Our formulation allows the time delay terms and their derivatives to be present in both the objective functional and the equality and inequality constraint equations. Our major results include a Lagrange Multiplier Rule involving Euler–Lagrange equations for delay differential equations and transversality conditions. Of special note is that these results will be used in later work by the authors to obtain new analytical techniques to solve general constrained problems involving delay differential equations for the Calculus of Variations and for Optimal Control Theory. They will also lead to new general, accurate, and efficient numerical methods to solve these important problems where no such methods exist at this time. Thus, for the first time, we will be able to solve this important class of problems obtaining analytic solutions for simpler problems and accurate numerical results for more complex problems when such a solution exists.
Delayed human herpes virus 6 encephalitis in a patient with allogeneic stem cell transplant.

Human herpes virus 6 (HHV-6) can become reactivated in immunosuppressed individuals typically within the first 50–100 days following an allogeneic stem cell transplant [1,2]. Invasion of neural tis...
Microstructure evolution during severe shear deformation at small length-scales

Microstructure evolution during severe shear in micrometer-scale sample sizes is examined by performing large-strain machining experiments inside a scanning electron microscope. The effect of depths of cut ranging from 1 to 10 μm on the mechanics is examined using digital image correlation of secondary electron images. The resulting microstructure is characterized via electron backscattered diffraction, which shows that with shrinking length-scales the gradual microstructure refinement observed for deeper cuts is replaced by abrupt but sporadic refinement mechanisms.
Depression in Substance-Dependent Delinquents

ABSTRACT Objective Depression often is comorbid with conduct disorder. The purpose of this study is to assess whether, among youths with conduct disorder, those with depression differ in other ways from those without depression. Method Ninety-nine delinquent boys (aged 13 through 19 years) were evaluated with the Diagnostic Interview Schedule for Children and other instruments. All boys had conduct disorder and substance use disorders. Results Staff-rated and self-rated depression scores correlated significantly. Twenty-one boys had major depression and/or dysthymia. Depressed boys had more substance dependence diagnoses and were more likely to have attention-deficit hyperactivity disorder, posttraumatic stress disorder, and anxiety disorders, compared with the nondepressed boys. Depressed boys tended to develop conduct symptoms earlier than did the nondepressed boys. Depression scores did not change after at least 4 weeks of abstinence, for either depressed or nondepressed boys. Conclusions Depressed delinquents have more substance dependence diagnoses, tend to initiate behavioral problems at an earlier age, have increased anxiety and attentional problems, and more trauma effects, than nondepressed delinquents. Depression does not appear to be related to substance intoxication, since it is not alleviated after 4 weeks of abstinence. Such boys may require combined psychiatric and substance treatment. J. Am. Acad. Child Adolesc. Psychlatry , 1995, 34, 6:764–771.
Arctic Marine Seismic Acquisition Feasibility: A Case Study Northeast of Greenland

The Northeast Greenland Shelf is one of many marine arctic areas with potential for significant hydrocarbon accumulations. However, to date, multichannel seismic data are missing north of 73 degrees due to Arctic pack-ice which usually covers the Northeast Greenland Shelf. Seismic data have become a prerequisite to drilling, particularly in expensive arctic areas. Noise due to operations on pack-ice can limit successful seismic acquisition. Hence, seismic acquisition feasibility can be the critical factor limiting future arctic oil exploration. The object of this study is to evaluate the feasibility of various concepts for acquiring multichannel seismic data from 73 to 80 degrees north in water depths less than 500 metres. These concepts include ice-reinforced seismic ships, submarine seismic, acquisition from floating ice, and land-fast-ice acquisition. This report concludes that it is feasible to acquire multichannel seismic data over Greenland's Northeast Continental Shelf north of 73 degrees.
Use of microwave-assisted evaporation for the complete recovery of volatile species of inorganic trace analytes

Solutions must often be evaporated prior to analysis either to preconcentrate the analyte or to eliminate an incompatible matrix component. Elimination of the halogen-based acids HCl and HF using t...
Standard Reference Materials to support US regulations for nutrients and contaminants in food and dietary supplements

To address the measurement and standard needs of the food and nutrition communities, the National Institute of Standards and Technology (NIST) has developed a suite of food-matrix Standard Reference Materials (SRMs) characterized for nutrient concentrations. These food-matrix SRMs include infant formula, baby food, and typical diet composites; meat homogenate, oyster, mussel, and fish tissues; baking chocolate; peanut butter; and spinach. Many of these materials were developed based on recommendations of the food industry to populate a nine-sectored triangle, developed by the Association of Analytical Communities (AOAC) International, in which foods are positioned based on their fat, protein, and carbohydrate contents. Value assignment of proximates, vitamins, and elements of nutritional interest in these food-matrix SRMs has been based primarily on the combination of results from measurements at NIST and from a group of collaborating laboratories involved in food measurements. Food-matrix SRMs are now available that are representative of all nine sectors of the AOAC International food-matrix triangle. Current activities are focused on the development of SRMs for dietary supplements including botanical and multivitamin/multielement materials.
Structure determination of soybean and wheat glucosylceramides by tandem mass spectrometry.

Glucosylceramide (GluCer) is a major sphingolipid of plant tissue and, thus, abundant in nature and in dietary food sources. The lipid backbones of mammalian GluCer (sphingosine, d18:1(delta4), and ceramide) induce cell death (apoptosis) and inhibit colon carcinogenesis, it is critical to know the structures of GluCer present in plants as a first step toward understanding this potential link between diet and cancer. This study characterized the molecular species of GluCer from soybean and wheat by low-resolution, high-resolution and tandem mass spectrometry. Soybean GluCer was comprised primarily (>95%) of ceramide with 4,8-sphingadiene (d18:2(delta4,delta8)) and alpha-hydroxypalmitic acid (h16:0); the remainder had the same backbone with h18:0, h20:0, h22:0 and h24:0 fatty acids. Wheat GluCer had three major ceramide, d18:2(delta4,delta8) with h16:0, d18:1(delta8) with h16:0 and d18: 2(delta4,delta8) with h20:0, and smaller amounts of other homologs. These backbones differ from those of mammalian sphingolipids, which often have a delta4-double bond (but rarely a delta8-double bond), and have alpha-hydroxy fatty acids in only some cases. Previously unexplained fragmentations that were diagnostic for the type of sphingoid base backbone (i.e. by homolytic cleavage of the doubly allylic C-6-C-7 bond to yield a stable distonic allylic radical cation and an allylic radical neutral) were also identified. Hence this method should be useful in the identification of double bonds in sphingolipids, and structure-function relationships between sphingolipids and colon carcinogenesis.
Chemical composition and antioxidant activity of seven cultivars of guava (Psidium guajava) fruits

The antioxidant activity and identification of phenolic compounds of seven edible guava (Psidium guajava) cultivars that varied in colour from white to pink were examined. In the DPPH assay all four pink-pulp guavas (Barbie Pink, Homestead, Sardina 1, Sardina 2) included in the study showed higher activity than the white pulp cultivars (Yen 2 and Sayla) and less than the red pulp guava cultivar (Thai Maroon). In the ABTS(+) assay this trend was the same up to 20 min, but from 20 to 40 min Barbie Pink showed lower activity than the white guavas. Twenty-one compounds were characterised in the cultivars, and ten of them are reported for the first time in this fruit. Principle component analysis was performed to identify differences in chemistry among these cultivars. Our results suggest that the antioxidant activity and phytochemical composition of P. guajava vary significantly according to the cultivar and pulp colour.
Quantitation of Permethylated N-Glycans through Multiple-Reaction Monitoring (MRM) LC-MS/MS

The important biological roles of glycans and their implications in disease development and progression have created a demand for the development of sensitive quantitative glycomics methods. Quantitation of glycans existing at low abundance is still analytically challenging. In this study, an N-linked glycans quantitation method using multiple-reaction monitoring (MRM) on a triple quadrupole instrument was developed. Optimum normalized collision energy (CE) for both sialylated and fucosylated N-glycan was determined to be 30%, whereas it was found to be 35% for either fucosylated or sialylated N-glycans. The optimum CE for mannose and complex type N-glycan was determined to be 35%. Additionally, the use of three transitions was shown to facilitate reliable quantitation. A total of 88 N-glycan compositions in human blood serum were quantified using this MRM approach. Reliable detection and quantitation of these glycans was achieved when the equivalence of 0.005 μL of blood serum was analyzed. Accordingly, N-glycans down to the 100th of a μL level can be reliably quantified in pooled human blood serum, spanning a dynamic concentration range of three orders of magnitude. MRM was also effectively utilized to quantitatively compare the expression of N-glycans derived from brain-targeting breast carcinoma cells (MDA-MB-231BR) and metastatic breast cancer cells (MDA-MB-231). Thus, the described MRM method of permethylated N-glycan enables a rapid and reliable identification and quantitation of glycans derived from glycoproteins purified or present in complex biological samples.
Envelope Solitary Waves and Periodic Waves in the AB Equations

This article deals with the envelope solitary waves and periodic waves in the AB equations that serve as model equations describing marginally unstable baroclinic wave packets in geophysical fluids and also ultra-short pulses in nonlinear optics. An envelope solitary wave has a width proportional to its velocity and inversely proportional to its amplitude. The velocity of the envelope solitary wave is partially dependent on its amplitude in the sense that the amplitude determines the upper or lower limit of the velocity. When two envelope solitary waves collide, they survive the collision and retain their identities except for a shift in the positions of both the envelopes and the carrier waves. The periodic wave solutions in sine wave form may be stable or unstable depending upon the wave parameters. When the sine wave is destabilized by small perturbations, its long-time evolution shows a Fermi–Pasta–Ulam-type oscillation.
The effect of the large hydrogen dissociation activation energy on an equilibrium-broadened hydrogen-oxygen diffusion flame

The structure of a hydrogen-oxygen diffusion flame under equilibrium conditions is dominated by the influence of the equilibrium constant for the hydrogen dissociation-recombination reaction. An attempt to continue a previous solution, which used the method of matched asymptotic expansions, to higher orders of approximation led to difficulties of a numerical kind as a result of the large rate-of-change of this equilibrium constant with temperature. It is shown how the matter can be resolved by using the asymptotic expansion method with the small parameter (reciprocal of the equilibrium constant) treated as a function of temperature; the solutions follow from a simple iterative procedure.
The role of kelp detritus in the growth of benthic suspension feeders in an understory kelp forest

Abstract Stands of understory kelps greatly alter the physical and biological environment within the algal canopy. In some regions, kelps can also contribute significantly to suspension feeder nutrition through detrital pathways. In a field experiment utilizing artificial kelps, we attempted to decouple and evaluate the physical versus nutritional mechanisms by which understory kelps affect the growth rates of benthic suspension feeders. Suspension feeding organisms were translocated to patches of real and artificial kelps at two subtidal sites, and growth rates measured. Physical parameters were not significantly different between treatments (real versus artificial kelp) and thus any differences in growth rate should be attributable to differences in detrital contribution between real and plastic plants. Of six taxa of suspension feeders examined, only one showed a significant treatment effect and that species grew faster in the artificial kelp treatment. The difference between our result and those of previously published studies may relate to issues of scale and species-specific plant secondary substances.