cssi/SciSciGPT-SciSciNet huggingface dataset:
Molecular Basis of C–S Bond Cleavage in the Glycyl Radical Enzyme Isethionate Sulfite-Lyase

Desulfonation of isethionate by the bacterial glycyl radical enzyme (GRE) isethionate sulfite-lyase (IslA) generates sulfite, a substrate for sulfite respiration that in turn produces the disease-associated metabolite hydrogen sulfide. Here, we present a 2.7 A resolution X-ray structure of wild-type IslA from Bilophila wadsworthia with isethionate bound. In comparison to other GREs, alternate positioning of the active site β strands allows for distinct residue positions to contribute to substrate binding. These structural differences combined with sequence variations create a highly tailored active site for the binding of the negatively charged isethionate substrate. Through the kinetic analysis of fourteen IslA variants, we probe the mechanism by which radical chemistry is used for C–S bond cleavage. This work further elucidates the structural basis of chemistry within the GRE superfamily and will inform structure-based inhibitor design of IsIA and thus of microbial hydrogen sulfide production.
Wnt2b Is Essential for Adrenocortical Progenitor Cell Fate and Zona Glomerulosa Identity in Vivo

Dysregulation of normal adrenal structure and function contributes to a spectrum of diseases from hypoplasia to cancer. Peripheral adrenocortical progenitor cells in the zona glomerulosa (zG) centripetally migrate and differentiate to replenish steroidogenic cells of the zG and the inner cortex over time. Both the fate of progenitor cells and aldosterone production by steroidogenic cells in the zG are regulated by Wnt/β-catenin signaling, but the cell-specific effects of individual WNT ligands in the adrenal cortex are not fully understood. To further characterize Wnt signaling components crucial for progenitor cell fate and zG identity, we analyzed mouse adrenals using single molecule in situ hybridization, which revealed the previously unknown expression of Wnt2b exclusively in the adrenal capsule. Wnt2b is co-expressed in the capsule with the Wnt signaling potentiator Rspo3, the loss of which causes zG depletion and reduced adrenal size in mice. Therefore, we hypothesized that capsular WNT2B activates Wnt signaling in the underlying zG to maintain the undifferentiated state of progenitor cells. To define the role of WNT2B in these processes, we first generated whole body Wnt2b knockout (KO) mice, which exhibit complete zG loss, as defined by known markers of zG identity (β-catenin and DAB2). To more fully determine the mechanism by which Wnt2b deletion results in zG loss, we crossed Wnt2b-floxed and capsule-specific Gli1-CreERT2 mice to generate a Wnt2b conditional knockout (cKO) model and study the effects of Wnt2b loss on the zG during homeostasis of the adult adrenal cortex. Gli1-CreERT2 activation by tamoxifen in 6-week-old mice significantly decreased Wnt2b expression and resulted in a lower adrenal-to-body weight ratio in Wnt2b cKOs compared to controls four weeks later. Adrenocortical proliferation (Ki67) was also significantly decreased in Wnt2b cKO mice, suggesting that WNT2B may promote progenitor cell self-renewal. To characterize the consequences of WNT2B loss on canonical Wnt signaling, we assessed activation of β-catenin, the primary Wnt signaling effector. High β-catenin activity in the zG observed in wild-type mice was disrupted in Wnt2b cKO mice, together with markedly reduced expression of adrenocortical Wnt target genes Axin2 and Wnt4. In addition, Wnt2b loss resulted in downregulation of steroidogenic genes Cyp11b2 and Hsd3b6. Together, these data reveal that capsule-derived WNT2B is required for zG differentiation and maintenance, potentially through activating adrenocortical Wnt/β-catenin signaling and downstream target gene expression involved in both progenitor cell fate and steroid-producing cell function. Studies to more fully elucidate the dynamic effects of WNT2B on the adrenal zG are ongoing as they have important implications for adrenal homeostasis and disease, including both primary adrenal failure and neoplasia.
Reactivity-guided formulation of composite solid polymer electrolytes for superior sodium metal batteries

Solid-state electrolytes (SSEs) can effectively address the dendrite growth and safety concerns associated with current battery technologies, but their implementation is still plagued by low ionic conductivity and high interfacial impedance. Herein, we report a reactivity-guided strategy towards the synthesis of a composite solid polymer electrolyte (SPE) with optimized compositions of polyester PPC, ceramic NASICON and the PEO host to simultaneously improve ionic conductivity, interfacial impedance, electrochemical stability, and mechanical properties. We formulate a novel synergistic approach that effectively increases the amorphousness of the composite SPE and forms an in situ sodium-ion conductive wetting layer upon contacting and reacting with the metallic sodium electrode to enable solid-state sodium metal batteries with superior performance. Compared to the conventional PEO electrolyte, the proposed composite SPE exhibits 25 times higher Na+ conductivity (0.12 mS cm−1) and 10 times lower interfacial impedance. Solid-state full cells are further demonstrated with nearly 90% capacity retention after cycling at 1C rate for 500 cycles.
NOSTALGIA AND THE BACKLOG: /R/PATIENTGAMERS AND THE TRANSACTIONAL NATURE OF LEISURE

This paper uses the findings of an investigation into the /r/patientgamers subreddit to account for the ways that our leisure time and our play have been assimilated by the logics of neoliberal, late capitalism. I do this by tracing classed experiences of slowness as experienced by video game players. The figure of the patientgamer was selected not just because of their protracted approach to video game consumption, but because the grows out of a frustration with the financial and temporal costs to access leisure. Through Foucauldian discourse analysis, two major themes were detected across a number of posts which traced how many players tried, and often failed, to slow down their lives in restful ways through their play and the conversations that emerged from the impulse to treat their leisure time as work. Specifically, users’ nostalgia for their childhoods and their anxieties around possessing a video game backlog are both emblematic of the way that video game play has been made legible to capitalist logics such that any distinction between labour and leisure becomes moot and attempt to lift from the patientgamer ethos some potential ways that the work of play may be reframed to undercut logics of efficiency and productivity. The case study of /r/patientgamers holds relevance not just for the study of games and/as culture, but of how technocapitalism instrumentalizes all leisure and the consequences felt by those who try to slow their rhythms of consumption but do so without proper attention to issues of class and power.
Prairie Fever: British Aristocrats in the American West, 1830–1890

Review of: "Prairie Fever: British Aristocrats in the American West, 1830–1890," by Peter Pagnamenta.
Impact of mTORC1 inhibition on keratinocyte proliferation during skin tumor promotion in wild-type and BK5.AktWT mice

In this study, we examined the impact of rapamycin on mTORC1 signaling during 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced keratinocyte proliferation and skin tumor promotion in both wild-type (FVB/N) and BK5.Akt(WT) mice. TPA activated mTORC1 signaling in a time-dependent manner in cultured primary mouse keratinocytes and a mouse keratinocyte cell line. Early activation (15-30 min) of mTORC1 signaling induced by TPA was mediated in part by PKC activation, whereas later activation (2-4 h) was mediated by activation of EGFR and Akt. BK5.Akt(WT) transgenic mice, where Akt1 is overexpressed in basal epidermis, are highly sensitive to TPA-induced epidermal proliferation and two-stage skin carcinogenesis. Targeting mTORC1 with rapamycin effectively inhibited TPA-induced epidermal hyperplasia and hyperproliferation as well as tumor promotion in a dose-dependent manner in both wild-type and BK5.Akt(WT) mice. A significant expansion (∼threefold) of the label retaining cell (LRC) population per hair follicle was observed in BK5.Akt(WT) mice compared to FVB/N mice. There was also a significant increase in K15 expressing cells in the hair follicle of transgenic mice that coincided with expression of phospho-Akt, phospho-S6K, and phospho-PRAS40, suggesting an important role of mTORC1 signaling in bulge-region keratinocyte stem cell (KSC) homeostasis. After 2 weeks of TPA treatment, LRCs had moved upward into the interfollicular epidermis from the bulge region of both wild-type and BK5.Akt(WT) mice. TPA-mediated LRC proliferation and migration was significantly inhibited by rapamycin. Collectively, the current data indicate that signaling through mTORC1 contributes significantly to the process of skin tumor promotion through effects on proliferation of the target cells for tumor development.
Doubting Free Will: Three Experiments

This paper describes three experiments that cast doubt on the existence of free will. All deal with the phenomenon that, for a variety of reasons, people do not consciously experience events (including their own “choices”) at the exact instant they occur. The existence of these delays is sufficient to cast serious doubt on the possibility of conscious free will, i.e., free will as we usually understand it. While these experiments do not definitely exclude the possibility of free will, they do provide affirmative evidence that our brains do not consciously make decisions in quite the way that introspection tells us. As such, they throw into question the factual basis of the freewill justification for purposefully inflicting serious human suffering as punishment. This paper is a break out from an earlier version of my companion paper, Free Will Ideology: Experiments, Evolution and Virtue Ethics, available at SSRN: http://ssrn.com/abstract=1428002.
A Review of: “Thomas Hegghammer. Jihad in Saudi Arabia: Violence and Pan-Islamism Since 1979.”

Thomas Hegghammer explores pan-Islamism and political violence in Saudi Arabia with careful attention to the evolution of jihadism since the Soviet invasion of Afghanistan. One key question the aut...
The feminine matrix of sex and gender in classical Athens

1. Introduction 2. Collapsing order: typologies of women in the speech against Neaira 3. Why is Diotima a priestess?: the feminine continuum in Plato's Symposium 4. Bringing the polis home: private performance and the civic gaze in Xenophon's Symposium 5. Sex and sacrifice in Aristophanes' Lysistrata 6. Conclusion.
Learning and Verifying Graphs Using Queries with a Focus on Edge Counting

We consider the problem of learning and verifying hidden graphs and their properties given query access to the graphs. We analyze various queries (edge detection, edge counting, shortest path), but we focus mainly on edge counting queries. We give an algorithm for learning graph partitions using O(nlogn) edge counting queries. We introduce a problem that has not been considered: verifying graphs with edge counting queries, and give a randomized algorithm with error i¾?for graph verification using O(log(1/i¾?)) edge counting queries. We examine the current state of the art and add some original results for edge detection and shortest path queries to give a more complete picture of the relative power of these queries to learn various graph classes. Finally, we relate our work to Freivalds' `fingerprinting technique' --- a probabilistic method for verifying that two matrices are equal by multiplying them by random vectors.
Efficient Querying and Animation of Periodic Spatio-Temporal Databases

We propose a representation of spatio-temporal objects with continuous and cyclic or acyclic periodic movements. We also describe an extended relational algebra query language for databases with such objects. We show that the new spatio-temporal databases are closed under the extended relational algebra queries, and each fixed relational algebra query can be evaluated in PTIME in the size of the input database.
Abstract P368: Genome Wide Association Study Identifies Susceptibility Loci for Coronary Artery Calcium in Smokers

Introduction: Coronary artery calcium (CAC) is a measure of coronary atherosclerosis, which is strongly associated with the presence of coronary artery disease and predicts future coronary disease events and mortality. CAC is a heritable trait. Numerous candidate gene studies and more recently genome-wide association studies (GWAS) have identified susceptibility loci for CAC. In addition, cardiovascular disease risk factors such as smoking are associated with CAC. Hypothesis: We hypothesized that we would identify new genetic loci and replicate known genomic regions for CAC by performing a GWAS among heavy smokers in the COPDGene study, a multi-center observational study designed to identify genetic factors associated with risk of COPD. Methods: We conducted a GWAS of CAC in COPDGene, a study of 10,192 current and former smokers with at least 10 pack-years of smoking history. CAC was measured from chest CT scans using an established protocol and was available in 8,739 individuals (6,150 non-Hispanic Whites and 2,589 African Americans). The analysis was performed using PLINK v1.07 adjusting for genetic ancestry using principal components as well as and cardiovascular disease risk factors (age, gender, BMI, smoking status, pack-years of smoking history, diabetes, high blood pressure, steroid use, high cholesterol, and presence of a coronary stent). Results: Using the log transformation of CAC plus 1 as the outcome, there were 9 single nucleotide polymorphisms (SNPs) on chromosome 9 [CDKN2B-AS1] that reached genome wide significance in non-Hispanic Whites, with the most significant result being rs10757272 (p = 3.572e-11). Additional top loci that have been previously identified were rs9349379 on chromosome 6 [PHACTR1] (p =8.760e-08) and rs1263982 on chromosome 17 [CA10] (p =4.654e-06). Among African Americans, no genome-wide significant associations were identified; however, one of the top findings was rs7412 on chromosome 19 [APOE] (p = 1.597e-06). Conclusions: This study confirms genome wide significance for CAC for CDKN2B-AS1 on chromosome 9 among non-Hispanic Whites. This is the major GWAS signal for clinically manifested coronary artery disease. Among African Americans, we found a suggestive association signal in the APOE gene. In conclusion, genetic susceptibility for atherosclerosis is evident, even among individuals with a substantial smoking burden. This highlights the importance of both genetics and behavioral risk factors in the susceptibility to atherosclerosis.
Use of selected reaction monitoring mass spectrometry for the detection of specific MHC class I peptide antigens on A3 supertype family members

The development of peptide-based vaccines that are useful in the therapeutic treatment of melanoma and other cancers ultimately requires the identification of a sufficient number of antigenic peptides so that most individuals, regardless of their major histocompatibility complex (MHC)-encoded class I molecule phenotype, can develop a cytotoxic T lymphocyte (CTL) response against one or more peptide components of the vaccine. While it is relatively easy to identify antigenic peptides that are presented by the most prevalent MHC class I molecules in the population, it is problematic to identify antigenic peptides that are presented by MHC class I molecules that have less frequent expression in the population. One manner in which this problem can be overcome is by taking advantage of known MHC class I supertypes, which are groupings of MHC class I molecules that bind peptides sharing a common motif. We have developed a mass spectrometric approach which can be used to determine if an antigenic peptide is naturally processed and presented by any given MHC class I molecule. This approach has been applied to the A3 supertype, and the results demonstrate that some, but not all, A3 supertype family-associated peptides can associate with all A3 supertype family members. The approach also demonstrates the shared nature of several newly identified peptide antigens. The use of this technology negates the need to test peptides for their ability to stimulate CTL responses in those cases where the peptide is not naturally processed and bound to the target MHC class I molecule of interest, thus allowing resources to be focused on the most promising vaccine candidates.
A General Method for Plasmid Isolation in Lactobacilli

A simple procedure for rapid isolation and detection of plasmid DNA fromLactobacillus species is described. Using an alkaline-detergent lysis method, plasmid DNA was released and characterized from cells treated with either mutanolysin or lysozyme for 1 h at 0°C. Treatment of cells with either enzyme at 37°C for 1h was detrimental to plasmid isolation and charaterization in someLactobacillus species. The procedure was effective with small volumes of cells and allowed rapid characterization of plasmid DNA inLactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus helveticus, andLactobacillus bulgaricus strains.
Characterization of the rat basilar artery in vitro

Segments of the rat basilar artery were examined in vitro for their mechanical responsiveness to a variety of vasoactive substances. Serotonin was the most potent agonist while norepinephrine elicited a dose-dependent relaxation. The findings lend support to the concept that there exists a marked heterogeneity amongst species in cerebrovascular responsiveness.
Distinguishing negatively-charged and highly conductive dislocations in gallium nitride using scanning Kelvin probe and conductive atomic force microscopy

Scanning Kelvin probe microscopy (SKPM) and conductive atomic force microscopy (C-AFM) are used to image surfaces of GaN grown by molecular beam epitaxy (MBE). Numerical simulations are used to assist in the interpretation of SKPM images. Detailed analysis of the same area using both techniques allows imaging of surface potential variations arising from the presence of negatively charged dislocations and dislocation-related current leakage paths. Correlations between the charge state of dislocations, conductivity of leakage current paths, and possibly dislocation type can thereby be established. Approximately 25% of the leakage paths appear to be spatially correlated with negatively charged dislocation features. This is approximately the level of correlation expected due to spatial overlap of randomly distributed, distinct features of the size observed, suggesting that the negatively charged dislocations are distinct from those responsible for localized leakage paths found in GaN. The effects of charged dislocation networks on the local potential profile is modeled and discussed.
Two forms of the pH 4 folding intermediate of apomyoglobin

Abstract The pH 4 folding intermediate of apomyoglobin exists in two forms (Ia, Ib) at equilibrium. Their ratio depends on pH, urea concentration and the presence or absence of a stabilizing anion (citrate, sulfate), and it does not depend on protein concentration. The Ia and Ib species are separated by a kinetic barrier and their interconversion can be monitored by tryptophan fluorescence in stopped-flow experiments. At pH 4.2, Ib is converted to Ia at low urea concentrations and urea unfolding gives the unfolding transition of Ia. During the refolding of native (N) apomyoglobin at pH 6, starting from the acid unfolded species (U), both Ia and Ib appear as transient intermediates and both Ia and Ib appear as transient intermediates in the acid-induced unfolding of N. The results are consistent with a linear folding and unfolding pathway: U ⇌ Ia ⇌ Ib ⇌ N. Apomyoglobin provides the opportunity to investigate at equilibrium the structures and properties of two different kinetic folding intermediates. A non-obligatory dimeric species of the pH 4 intermediate is formed slowly and contributes to the refolding kinetics at concentrations above 5 μM. The dimer dissociates slowly and during refolding at pH 6 it forms N in a later time range than does the monomer.
The relationship of corn oil and animal fats to serum cholesterol values at various dietary protein levels.

A high level of dietary protein lowered serum cholesterol. Incorporation of increasing amounts of beef tallow did not increase the serum cholesterol levels significantly, and some dietary fat was found to be desirable. Addition of up to 0.3% of dietary cholesterol did not significantly increase the serum cholesterol levels on either low or high levels of dietary fat or protein. The energy protein (E/P) ratio of a diet had a significant effect on serum and carcass cholesterol levels. The type of fat had an effect on serum cholesterol levels, but with lowering of the E/P ratio this effect became negligible.
Reduced diameter spheres increases the risk of chest blow–induced ventricular fibrillation (commotio cordis)

Background Sudden death due to low-energy blunt trauma to the precordium (commotio cordis) has been described with a variety of sporting objects. However, the risk of ventricular fibrillation (VF) relative to the shape of the impact object is not known. Objective The objective of the current experiment is to test whether the impact object shape is a clinical variable that affects the risk for commotio cordis. Methods In a juvenile swine model, impacts were given in random order with two different spherical shapes (72 mm diameter, equivalent to a baseball; 42 mm diameter, equivalent to a golf ball) and a flat round object 72 mm in diameter. Objects were equal in weight (150 g), thrown at 30 mph, and gated to the vulnerable portion of the cardiac cycle. Results Sixteen swine received 144 impacts. The flat object did not cause VF ( P = .01 compared with the two spherical objects), nonsustained VF, ST elevation, or bundle branch block. The smaller diameter sphere caused VF in nine of 48 impacts (19%), and the larger diameter sphere caused VF in five of 48 impacts (10%; P = .25). The smaller diameter sphere was associated with a greater increase in left ventricular pressure ( P P = .001 compared with larger sphere only) and a higher likelihood of ST segment elevations ( P P = .08 compared with larger sphere only) and bundle branch block (Fisher's exact P = .008, and Fisher's exact P = .18 compared with larger sphere only). Conclusion The shape of the projectile markedly influences the risk of VF from chest wall impact. This effect is likely mediated via a greater increase in left ventricular pressure with smaller diameter objects. Spreading the impact force over a larger area may decrease the risk of sudden death and has implications for the design of protective athletic equipment.
THE KINETICS AND INFRARED SPECTROSCOPY OF C1 HYDROCARBONS ADSORBED ON CLEAN AND OXYGEN-MODIFIED Mo(100)

The surface infrared spectra (700–2300 cm-1) of CH3I, CD3I, CH2I2 and CD2I2 adsorbed on Mo(100) at 80 K have been observed and assigned. The strongest infrared absorption of CH3I is the δs(CH3) mode at 1236 cm-1, which shifts significantly on heating the surface to 135 K, yielding a new peak at 1106 cm-1 indicating the formation of a surface-CH3 species. This new feature dominates the spectrum after annealing to 160 K and disappears at 235 K, where the TPD results show the desorption of methane. This chemistry was also studied on oxygen-covered Mo(100) with oxygen coverages of 1.0 and 1.5. These were not found to substantially affect the surface chemistry. When CH2I2 is adsorbed on Mo(100), the ω(CH2) mode at 1107 cm-1 is the strongest feature, and when one heats the sample to 135 K, a new peak appears at 1061 cm-1 which is ascribed to the formation of a surface-CH2I species. This peak disappears on heating at about 200 K, where previous ultraviolet-photoelectron-spectroscopic data showed the formation of a surface-C1 species. No RAIRS data have been reported for adsorbed-methylene species, because of either a low-adsorption cross section or the lack of appropriate symmetry of these modes. The deuterated molecules show the same effects except that peaks are shifted as expected so that ν(H)/ν(D) ~1.35.
Professional organizations in the emergency department

It is not so important the specific professional organizations to which one belongs, but rather one's activity in the organization and his or her willingness to get involved and contribute to it. The relevance of a professional organization to a member of the ED staff is only as valid as the level of participation by that member in the professional organization. Membership in any organization, including a professional organization, is a contractual two-way street. The individual or the group of individuals gives something to the professional organization and the professional organization gives something back to the individual or the group of individuals. The relationship is only as strong a link as the effort that both parties are willing to commit. There are also many instances in which individuals in the ED are passive beneficiaries or recipients of activities and functions of a professional organization because the professional organization provides benefits to all members of a class without requiring membership. An excellent example of this is national legislation and the regulations that follow, such as EMTALA and Medicare funding. Professional organizations can play many roles in the EDs of America. Their relative applicability and need depends entirely on the unique characteristics of each ED and its staff.
Complementary and Alternative Provider Use by Insured Patients with Diabetes in Washington State

Objectives: The authors investigated whether insurance coverage for complementary and alternative medicine (CAM) providers is associated with increased medical care use among diabetes patients. Predictors of CAM use and how CAM affects health care use and expenditures under insurance coverage were examined. Design: Claims data from two large insurers in Washington State were obtained for 2002. Types of providers used, comorbid medical conditions, number of visits, and expenditures were calculated for the study sample and compared to a nondiabetic matched group. Results: Of the 20,722 adults with diabetes, 3605 (17.4%) had one or more visits to any licensed CAM provider (mostly chiropractors). This was lower than the 20% CAM use in the comparison group. Diabetes patients who used CAM were more likely to have multiple other medical problems than CAM nonusers. CAM users had a higher average number of annual outpatient visits compared to nonusers (28 versus 16), and higher average annual expenditures ($8,736 ...
Emerging biobehavioral factors of fatigue in sickle cell disease.

Purpose: The symptom most frequently associated with sickle cell disease (SCD) is pain, but recent research is beginning to indicate that fatigue as an increasingly important symptom of this disease upon which to focus research efforts. This article explores biological and behavioral factors that can potentially contribute to fatigue in SCD. Organizing Framework: A biobehavioral framework guides this discussion of factors that may contribute to SCD fatigue. Findings: The pathophysiology of the disease process, such as the profound hemolytic anemia and unpredictable vasoocclusive crises, suggests that individuals with SCD are at risk for both acute and chronic fatigue. For example, hypoxemia can cause muscle weakness and produce oxidative stress, which, in turn, increases fatigue. Sickled erythrocytes disrupt the vascular endothelium and stimulate proinflammatory cytokines, which are linked to sleep disruptions. Pain, the most notorious symptom of SCD, has a complex and mechanistically poorly understood relationship with fatigue. Conclusions: Little is known about the symptom of fatigue in SCD. Considering the biological and behavioral factors of SCD that could potentially contribute to fatigue, there is a great need for research on the nature and potential mechanisms of fatigue in SCD. Clinical Relevance: Fatigue in SCD may negatively affect quality of life. Understanding factors that may contribute to fatigue aids the clinician in identifying causes and determining treatment.
Periodic components of hand acceleration/deceleration impulses during telemanipulation

Responsiveness is the ability of a telemanipulator to recreate user trajectories and impedance in time and space. For trajectory production, a key determinant of responsiveness is the ability of the system to accept user inputs, which are forces on the master handle generated by user hand acceleration/deceleration (a/d) impulses, and translate them into slave arm acceleration/deceleration. This paper presents observations of master controller a/d impulses during completion of a simple target acquisition task. Power spectral density functions calculated from hand controller a/d impulses were used to assess impulse waveform. The relative contributions of frequency intervals ranging up to 25 Hz for three spatially different versions of the task were used to determine which frequencies were most important. The highest relative power was observed in frequencies between 1 Hz and 6 Hz. The key frequencies related to task difficult were in the range from 2 Hz to 8 Hz. Differences were also observed from 9 Hz to 12 Hz. The results provide clues to the source of the performance inhibition.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Measurement of residual stresses in sapphire fiber composites using optical fluorescence

Abstract The residual stresses in c-axis sapphire fibers in a γ-TiAl matrix and in a polycrystalline Al2O3 matrix as a function of distance below a surface are determined. They are obtained from the shift in frequency of the characteristic R2 fluorescence line of chromium in sapphire obtained by focusing an optical probe at different depths in a sapphire fiber intersecting the surface of the composite. The method is described together with its calibration. Both the axial and radial components of the residual stress in the fiber are observed to vary over a depth of approximately the fiber diameter and are then almost independent of depth.
Computers in Physician Licensure and Certification: New Methods of Assessment:

The newer methods of assessment that could become part of a licensure or certification program for physicians in the next decade include standardized patients which assess clinical skills and four computer-based methods that provide an assessment of cognitive ability: simple computerized tests, computer simulations, adapting item presentation, and continuous testing. The prognosis for standardized patients is mixed, with implementation more likely to occur outside of the U.S. Over the next five years, simple computerized tests will be implemented and significant strides will be made in computer simulations and adapting item presentations. These two methods should be implemented toward the end of the decade. The prognosis for the use of continuous testing is poor because so much fundamental work is needed.
A flow dialysis technique for the measurement of free testosterone in human plasma under physiologic conditions

Abstract A technique is described for measuring the percentage of free (unbound) testosterone under physiologic conditions (37°C in whole plasma) without disturbance of the equilibrium state. The technique employs 10 ml of whole plasma with a tracer amount of tritiated testosterone in a flow dialysis cell. The precision of the technique is 5–10%. The percentage of free testosterone values so obtained for several samples of human plasma are in general agreement with previous estimates. The technique permits re-evaluation of individual plasma samples several times, and it can be easily generalized to the study of other steroids in whole blood or plasma. The free testosterone is generally believed to be the biologically active portion of the plasma testosterone (1, 2). Free testosterone is that portion of the total which is not bound to plasma binding species. Practically speaking, the free testosterone fraction is that portion of testosterone in plasma which is capable of diffusing through a dialysis membrane. A technique has been described by Colowick and Womack (3) for the measurement of the percentage of diffusible molecules at equilibrium without significantly disturbing the equilibrium state. An apparatus is described here which is a modification of that used by Colowick and Womack and which permits measurement of the percentage of free steroid in plasma under physiologic conditions.
On Slater's transition state for ionization energies

Abstract For theXα- and the Xαβ-exchange appropriation the transition state for concept for estimating ionzation energies is analyzed mainly in atomic systems. Comparisons with HF results and experimental data are presented to put the different theoretical approach in proper perspectives.
Conventional heart rate variability analysis of ambulatory electrocardiographiic recording fails to predict imminent ventricular fibrillation

OBJECTIVES. The purpose of this report was to study heart rate variability in Holter recordings of patients who experienced ventricular fibrillation during the recording. BACKGROUND. Decreased heart rate variability is recognized as a long-term predictor of overall and arrhythmic death after myocardial infarction. It was therefore postulated that heart rate variability would be lowest when measured immediately before ventricular fibrillation. METHODS. Conventional indexes of heart rate variability were calculated from Holter recordings of 24 patients with structural heart disease who had ventricular fibrillation during monitoring. The control group consisted of 19 patients with coronary artery disease, of comparable age and left ventricular ejection fraction, who had nonsustained ventricular tachycardia but no ventricular fibrillation. RESULTS. Heart rate variability did not differ between the two groups, and no consistent trends in heart rate variability were observed before ventricular fibrillation occurred. CONCLUSIONS. Although conventional heart rate variability is an independent long-term predictor of adverse outcome after myocardial infarction, its clinical utility as a short-term predictor of life-threatening arrhythmias remains to be elucidated.
Detection of phosphorus oxyanions in synthetic geothermal water using ion chromatography-mass spectrometry techniques.

Abstract Recent developments in microbiology suggest that reduced inorganic phosphorus oxyanions, including hypophosphite and phosphite, may be present in nature. These studies have inspired the development of specific and sensitive methods that detect phosphorus oxyanions in natural water. This paper will discuss a new technique that couples suppressed conductivity ion chromatography (Dionex AS17 analytical column and potassium hydroxide eluent) with electrospray mass spectrometry (IC/MS) with limits of detection nearly 200 times lower than those reported using suppressed conductivity detection. The technique was optimized for the detection of hypophosphite, phosphite, and phosphate in a synthetic geothermal water matrix. Samples were pre-treated with silver and sulfonic acid cartridges, and injection loop sizes as large as 800 μl were employed to enhance instrument sensitivity. All peaks were clearly resolved, and calibrations were linear with estimated 3 σ limits of detection of 0.011, 0.0020, and 0.029 μM for hypophosphite, phosphite, and phosphate, respectively.
Multiculturalism, universalism, and science education

Multiculturalists have recently raised a number of important challenges to the school curriculum, including whose knowledge are we teaching? and who benefits and loses by existing approaches to the curriculum? In this article we examine a number of issues in this debate that are of primary importance to science educators. These issues include: (1) problems with the universalist account of the nature of science that has been the most powerful defense against multiculturalism; (2) an examination of some historical cases that illuminate the consequences of maintaining a universalist perspective on science; and (3) an argument for a multicultural perspective on scientific knowledge. These issues are examined in the context of a national science education reform in which there is considerable consensus that the science curriculum should include teaching about the nature of science. We argue that the nature of science taught in school should reflect a multicultural perspective on scientific knowledge. © 1994 John Wiley & Sons, Inc.
Microlaser-pumped periodically poled lithium niobate optical parametric generator-optical parametric amplifier.

For what is believed to be the first time, a single-longitudinal-mode passively Q-switched Nd:YAG microlaser is used to pump a narrow-bandwidth periodically poled lithium niobate (PPLN) optical parametric generator–optical parametric amplifier (OPG–OPA). Before amplification in the OPA, the output of the OPG stage was spectrally filtered with an air-spaced etalon, resulting in spectroscopically useful radiation (bandwidth, ∼0.05 cm-1 FWHM) that was tunable in 15‐cm-1 segments anywhere in the signal range 6820–6220 cm-1 and the idler range 2580–3180 cm-1. The ability to pump an OPG–OPA with compact, high-repetition-rate, intrinsically narrow-bandwidth microlasers is made possible by the high gain of PPLN. The result is a tunable light source that is well suited for use in portable spectroscopic gas sensors.
Effect of light and water stress on mineral element composition of plants 1

Many factors affect the composition of mineral elements in plants. The effects of many of these factors, such as element concentration, temperature, pH, plant part, plant age, metabolic inhibitors, element interactions, fertilizer, and type of soil, have been studied extensively by many scientists who are concerned with plant mineral nutrition. However, relatively few studies have focused on the effects of light and water stress. The objective of this review was to consider some of the effects that light and water stress have on the mineral element composition of plants.
The return of subducted continental crust in Samoan lavas

to date. The data are consistent with the presence of a recycled sediment component (with a composition similar to the upper continental crust) in the Samoan mantle. Trace-element data show affinities similar to those of the upper continental crust— including exceptionally low Ce/Pb and Nb/U ratios 8 —that complement the enriched 87 Sr/ 86 Sr and 143 Nd/ 144 Nd isotope signatures. The geochemical evidence from these Samoan lavas significantly redefines the composition of the EM2 (enriched mantle 2; ref. 9) mantle endmember, and points to the presence of an ancient recycled upper continental crust component in the Samoan mantle plume. The Earth’s mantle, as sampled by ocean island basalts erupted at hotspots, is chemically and isotopically heterogeneous. However, the origin of the geochemical heterogeneity of the mantle is not well understood. One model for the geochemical evolution of the mantle assumes thatmuchof thechemical diversity isaresultof subduction, a tectonic process that introduces enriched oceanic crust and compositionally heterogeneous sediment into a largely primitive (or slightly depleted) mantle 5,10,11 . Following subduction, these surface materials mix with a peridotitic mantle, thus imprinting their enriched chemical and isotopic signatures on its various domains. A number of isotopically distinct geochemical reservoirs, as sampled by ocean island basalts, have resulted from this process. The isotopic
Design, synthesis, and biological evaluation of (E)- and (Z)-styryl-2-acetoxyphenyl sulfides and sulfones as cyclooxygenase-2 inhibitors

A new series of styryl acetoxyphenyl sulfides and sulfones possessing (E)- and (Z)-configurations were designed and prepared by stereospecific syntheses. All these compounds were evaluated for their ability to inhibit COX-2 enzyme in vitro. Structure-activity relationship studies on these compounds revealed that only sulfides with (Z)-configuration have potential COX-2 inhibitory activity. This inactivation of the enzyme is believed to be due to the selective covalent modification of COX-2 by the inhibitors.
Do adverse childhood experiences increase the risk of postdeployment posttraumatic stress disorder in US Marines

Posttraumatic stress disorder (PTSD) has been associated with combat intensity, lack of social support, and adverse childhood factors among military personnel in previous studies. It has not been well established if adverse childhood experiences reported predeployment are independently associated with postdeployment PTSD. Data were evaluated from 8,391 male responders of the Recruit Assessment Program survey at Marine Corps Recruit Depot in San Diego who were deployed in support of military conflicts between September 2001 and June 2004. Using patient medical records to determine PTSD diagnoses, Cox proportional hazard modeling was performed to examine if adverse childhood experiences were independently associated with postdeployment PTSD. After adjustment, those who reported adverse childhood experiences in more than one category were significantly more likely to be diagnosed with postdeployment PTSD. Specifically, childhood physical neglect was mostly strongly associated with postdeployment PTSD. Findings suggest that Marines who experience multiple types of adverse childhood experiences may be at increased risk for postdeployment PTSD. It is possible, however, that these results indicate that men willing to report childhood adverse experiences are also more willing to seek care for PTSD.
Effects of Adoption of International Financial Reporting Standards in Belgium: The Evidence from BEL-20 Companies

Abstract This study examines the adoption of International Financial Reporting Standards (IFRS) by BEL-20 companies in Belgium. The research analyses the application of IFRS in the consolidated financial statements of Belgian publicly traded companies. In Belgium, as in several other continental European countries, a close link exists between accounting and taxation. The study provides insight into IFRS implementation problems based on a survey sent to BEL-20 companies. The survey focused on the impact that IFRS conversion has on companies, their internal organization and accounting and finance strategy. The benefits and challenges of the adoption of IFRS are analysed, as well as the level of understanding and experience with IFRS, perception of the quality of IFRS, and the impact of adoption of IFRS on consolidated equity and net income. Principal differences between IFRS and Belgian generally accepted accounting principles (GAAP), having a major impact on the conversion to IFRS, are identified. This stu...
Determination of the glyceride structure of fats: Anomalous features of the seed fat of bitter gourd (Momordica charantia)

Glyceride composition of the seed fat ofMomordica charantia has been determined by gas liquid chromatography (GLC) of oxidized esterifield glycerides. Stearodiunsaturated glycerides form ca. 80% of the total glycerides. Values obtained by the above method agree closely with those obtained by Youngs' (8) method. However, there is a wide variation between the present results and those calculated according to Vander-Wal (5) from lipase hydrolysis data. Possible reasons for this anomalous glyceride pattern are discussed.
l-Gulono-γ-lactone oxidase and dehydrogenase

An enzyme from rat-liver microsomes which catalyzes the aerobic oxidation of l-gulono-γ-lactone to l-ascorbate has been studied. A sensitive and convenient aerobic optical assay procedure based on the reduction of 2,6-dichlorophenolindophenol in the presence of phenazine methosulfate is described. The activity determined in this assay procedure is defined as l-gulono-γ-lactone dehydrogenase activity as opposed to l-gulono-γ-lactone oxidase activity, which is assayed by measuring the formation of l-ascorbate with oxygen as electron acceptor. By both assays a value of Km for l-gulono-γ-lactone of 4 · 10−4M was obtained. The l-gulono-γ-lactone oxidase reaction is insensitive to azide, cyanide, antimycin A, amytal, and diisopropylfluorophosphate; it is, however, reversibly inhibited by p-chloromercuribenzoate. The rate of the oxidase reaction is 2 to 3 times higher in 100% oxygen than in air. Since the dehydrogenase can be obtained in soluble form free of oxidase activity, it appears that the oxidase consists either of an autooxidizable dehydrogenase which is altered during the fractionation procedure, or of a dehydrogenase and one or more components of electron transport which is removed or denatured during the fractionation procedure. It is not known if a flavin or cytochrome b5 is involved in the oxidase reaction. Evidence has been presented which indicates that the inability of guinea pigs and primates to synthesize l-ascorbic acid is due to a deficiency of the l-gulono-γ-lactone dehydrogenase reaction, although it is not possible to exclude the possible deficiency of an additional component of the oxidase system. No evidence was found which would suggest that primate and guinea pig liver preparations contain an inhibitor of l-gulono-γ-lactone oxidase or dehydrogenase.
Observation of the Auger Resonant Raman Effect

Monochromatized synchrotron radiation near the photoionization threshold was used to produce the (2p/sub 3/2/) vacancy state in atomic Xe. Deexcitation of the state through L/sub 3/-M/sub 4/M/sub 5/(/sup 1/G/sub 4/) Auger-electron emission was measured. The 5d spectator-electron Auger satellite was observed. The satellite energy exhibits linear dispersion. The observed width of the /sup 1/G diagram line decreases by approx. 40% when the exciting photon energy reaches the vicinity of the Xe L/sub 3/ binding energy. This radiationless process can thus be construed as the Auger analog of the x-ray resonant Raman effect. The /sup 1/G diagram line is shifted by -+3 eV due to post-collision interaction; this shift varies with excitation energy.
Systemic neutrophil intrinsic 5-lipoxygenase activity and CD18 receptor expression linked to reperfusion injury.

Objective: To determine if systemic neutrophil intrinsic 5-lipoxygenase (5-LO) inhibition correlates with decreased expression of surface adhesion molecules and attenuation of ischemia-reperfusion (i/r) injury in guinea pig island skin flaps. Methods: Eighty-one adult female Hartley guinea pigs were divided into one control group, three 2-hour ischemia groups, and four 10-hour ischemia groups. Island dorsal skin flaps were developed (except in the control group), and 2 hours before reperfusion, zileutin (a 5-LO inhibitor) or vehicle was administered orally. Postreperfusion systemic neutrophil receptor expression, neutrophil flap infiltration, and flap survival were measured. Neutrophils from whole blood were analyzed for CD 18 containing surface receptor expression using monoclonal antibodies and cell associated fluorescence. Neutrophil infiltration into a distal centimeter squared of flap tissue was assessed using myeloperoxidase antibodies, and flap survival was determined within 7 days postoperatively. Results: Flaps in the treated 2− and 10-hour ischemic groups survived totally intact, while the untreated 10-hour ischemic flaps underwent total necrosis. A significant main effect of the drug was detected using analysis of variance (ANOVA) (P =.0001). Surface receptor detection and neutrophil infiltration were significantly increased in the untreated animals. Conclusions: Zileuton, a 5-LO inhibitor, reduces adhesion receptor expression on systemic neutrophils and attenuates i/r injury. Systemic neutrophil intrinsic 5-LO activity and CD18 receptor expression are linked to reperfusion injury and may be fundamental events in its pathogenesis.