cssi/SciSciGPT-SciSciNet huggingface dataset:
Direct and Indirect Effects of Environmental Contaminants on Amphibians

Abstract Amphibians are the vertebrate group with the highest percentage of species listed as decreasing and threatened with extinction. They are in this predicament because of their unique life histories and adaptations that make them ecological lynchpins, in concert with many uninformed and unwise choices of modern societies. Amphibians are being devastated by losses of habitat, overharvest, climate change, exotic species, infectious pathogens, and contaminants—and many interactions among these stressors. Among the ~ 8000 species of amphibians, there are > 7000 species of frogs, 700 species of salamanders, and 200 species of caecilians, but very few species have been studied in regard to their health needs or the impacts of chemical contaminants. Different groups, species within groups, and developmental stages of amphibians have different exposures to contaminants and varied susceptibilities. Contaminants can cause direct toxicity that may affect any and all body systems and processes. They may also alter ecosystems in ways that deprive amphibians of oxygen, food, shelter, and hygiene. Highly important contaminants that harm amphibians directly and/or indirectly include nutrients, acids, heavy metals, insecticides, herbicides, fungicides, and salts. Vigorous ecological restoration efforts that include ways to avoid chemical contamination hold promise for recovery of our charismatic amphibian relatives.
Magnetic resonance imaging anatomy and morphometry of lumbar intervertebral foramina to guide safe transforaminal subarachnoid punctures

Percutaneous transforaminal lumbar punctures (TFLPs) offer alternative access routes to the lumbar subarachnoid cistern. Safe fluoroscopic insertion of a needle through a lumbar intervertebral foramen (IVF) should ideally avoid the exiting spinal nerve and surrounding vascular pedicles. A crescentic region in the posterior aspect of IVF is the conventional position for needle placement during TFLP, but the underlying anatomic basis for this has not been evaluated fully. To enhance TFLP safety, we defined the morphometry of normal lumbar IVFs and precise locations of neurovascular structures in the IVF posterior crescent. We retrospectively reviewed high-resolution T2-weighted lumbar spine magnetic resonance images of 40 normal adults to establish normative dimensions of each IVF from L1 to L5 bilaterally. We segmented the IVF posterior crescent into three parts, and within each, measured the areas occupied by neurovascular structures. We statistically correlated the presence or absence of neurovascular structures in each crescent segment using a chi-square test. The mean morphometrics for all 304 IVFs in 10 males and 30 females of similar ages were: area 115.3 ± 29.5 mm2 ; height 18.0 ± 2.4 mm; and width at mid-disc level 5.6 ± 2.1 mm. We found a significant association between crescent segment and presence or absence of neurovascular structures (χ2 = 95.9, p < .001). A post-hoc calculation of adjusted standardized residuals identified a significant association between the middle crescent segment and absence of neurovascular structures. Thus, the middle segment of the IVF posterior crescent is significantly most devoid of neurovascular structures, and more often would be the safest target for needle placement during TFLP.
On Supramolecular Self-Assembly: Interview with Samuel Stupp

Ranging from 2D assemblies to peptide amphiphile-based biomaterials, Prof. Samuel Stupp and his team have enriched the scientific community with many breakthroughs in the field of supramolecular self-assembly. This Interview offers the unique possibility to share some highlights along his journey, providing also a glimpse to his vision of the future of supramolecular chemistry. Interdisciplinarity is an integral part of Prof. Stupp's research philosophy, and, using his own words, "it is the only way to understand the complex universe around us and help society along the way". What a great guideline to us all!
Changes in knee adduction moment wearing a variable-stiffness shoe correlate with changes in pain and mechanically stimulated cartilage oligomeric matrix levels.

This study aimed to determine if changes in knee adduction moment (KAM) after 6 months of variable-stiffness shoe wear are associated with changes in symptoms or serum levels of cartilage oligomeric matrix protein (COMP) following a mechanical stimulus in subjects with medial knee osteoarthritis (OA). Twenty-five subjects were enrolled in the study and assigned a variable-stiffness shoe, and 19 subjects completed the 6-month follow-up. At baseline and follow-up subjects underwent gait analysis in control and variable-stiffness shoes, completed Western Ontario and McMaster Universities (WOMAC) questionnaires, and serum COMP concentrations were measured immediately before, 3.5 and 5.5 hours after a 30-minute walking activity. Relationships between changes in KAM (first peak and impulse) and changes in (a) COMP levels in response to the 30-minute walking activity and (b) WOMAC scores from baseline to 6-month follow-up were assessed by Pearson correlation coefficients. Changes in first peak KAM were associated with changes in COMP levels 5.5 hours postactivity from baseline to follow-up (R = .564, P = .045). Subjects with greater reductions in KAM had larger decreases in COMP (expressed as a percent of preactivity levels) at follow-up. Subjects with greater reductions in KAM impulse had significantly greater improvements in WOMAC Pain (R = -.56, P = .015) and Function (R = -.52, P = .028) scores at follow-up. The study results demonstrated the magnitude of reduction in the KAM wearing a variable-stiffness shoe is associated with decreases in mechanically stimulated COMP levels and pain/function. This work suggests that interactions between COMP and joint loading during walking should be further investigated in future studies of treatment outcomes in OA.
Detection of Merkel cell polyomavirus in formalin-fixed, paraffin-embedded tissue of Merkel cell carcinoma and its correlation with prognosis

6027 Background: Polyomaviruses are frequently associated with malignancies in their hosts. Recently, a novel polyoma virus, named Merkel cell polyomavirus (MCV) was identified integrated to the ge...
More is more: Explicit intertextuality in university writing placement exam essays

Abstract The ability to draw on information from published sources within one’s own texts is an important skill in academic writing at the university level. This study analyzed the source integration techniques employed by 99 students on an integrated reading-to write placement exam at an American university, with particular focus on direct quotes and citation phraseology. Patterns of direct quotation varied by course placement level, with advanced writers quoting more frequently and selecting shorter segments of source material. Writers at all four levels favored integral over non-integral (parenthetical) citation, and most often employed the Author + Reporting Verb phrasing pattern. Advanced writers cited more frequently, selected a wider variety of reporting verbs, and employed more “writerly act” verbs to express their own evaluation of the cited content. The implications for pedagogy, and placement are discussed.
Measuring muscle quality: associations between echo intensity and normalized strength and power

OBJECTIVE Muscle quality has received considerable attention within the literature due to its influence on health and performance. However, it has been assessed by various measures (e.g. ultrasound imaging, normalized strength), contributing to the lack of a consensus definition. The purpose of this study was to investigate the association between common muscle quality measures: vastus lateralis echo intensity (EI) and peak torque (PT) and power (PP) normalized to thigh lean mass (TLM) and thigh fat mass (TFM). APPROACH Participants' body composition was assessed via dual-energy Xray absorptiometry and custom thigh analysis. Subcutaneous fat-correction muscle EI was assessed via ultrasonography. Maximal strength and power assessments of the dominant leg extensors were completed. Maximal PT and PP was normalized to TLM and TFM, respectively. Pearson product-moment correlations were used to determine the relationships between EI and PT/TLM, PT/TFM, PP/TLM, and PP/TFM. MAIN RESULTS Greater muscle EI was significantly related with lower PT/TFM and PP/TFM (r=-0.74 - -0.70, P<0.001), but unrelated to PT/TLM or PP/TLM (P≥0.205). SIGNIFICANCE These findings suggest that muscle EI and normalized strength and power may not be used interchangeably to define muscle quality, and muscle EI may be more sensitive to the adiposity of the limb. Future studies should consider using unique definitions for these separate measures.
Atmospheric Deposition and Annual Flux of Legacy Perfluoroalkyl Substances and Replacement Perfluoroalkyl Ether Carboxylic Acids in Wilmington, NC, USA

Wet deposition and dry deposition of legacy per- and polyfluoroalkyl substances (PFAS) and perfluoroalkyl ether carboxylic acids (PFECAs) were assessed on the southeastern coast of the United States, specifically, in Wilmington, NC, which is located 110 km from a fluorochemical manufacturer. Analytes were quantified by liquid chromatography coupled to electrospray ionization with triple-quadrupole mass spectrometry. Total concentrations of six PFAS compounds ranged from below the method quantification limit to 110 ng L–¹ by wet deposition, and total fluxes of 0.3–29 ng m–² day–¹ by dry deposition were found. The estimated annual flux of all six PFAS was 30 μg m–² by wet deposition and 1.4 μg m–² by dry deposition, indicating that PFAS are more effectively removed from the atmosphere by wet deposition. There was a significant rainout/washout effect observed in our data, but there was no impact of the origin of the air mass on concentration or flux, suggesting that the incorporation of PFAS into rainwater is a relatively local phenomenon. This study shows the first direct evidence of PFECAs in wet and dry deposition. The data suggest that the particle-bound and gas-phase PFAS that may have undergone long-range transport can be incorporated into raindrops and removed rapidly.
Association between spinal stenosis and wild-type ATTR amyloidosis.

Age-related cardiac amyloidosis results from deposits of wild-type tranthyretin amyloid (ATTRwt) in cardiac tissue. ATTR may play a role in carpal tunnel syndrome (CTS) and in spinal stenosis (SS),...
Effectiveness of COVID-19 Convalescent Plasma Infusion Within 48 Hours of Hospitalization With SARS-CoV-2 Infection

On January 30, 2020, the World Health Organization (WHO) declared the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic a worldwide emergency. Worldwide there have been 170 million cases of the resulting disease coronavirus 2019 (COVID-19), of those, 3.53 million have resulted in death. The Food and Drug Administration (FDA) with Mayo Clinic as the lead institution authorized COVID-19 convalescent plasma (CCP) for treatment of SARS-CoV-2 infection. Effective therapeutic window for CCP administration had yet to be defined. We addressed this gap by characterizing longitudinal biologic response and clinical outcomes of COVID-19 patients treated with CCP. Primary outcome was discharged to home/home health.
The Active Times of Jerome Hershman, MD: An Interview with the Founding Editor of Thyroid About a Life Devoted to the Thyroid Gland (and Other Things).

Dr Jerome Hershman is a Distinguished Professor Emeritus at the David Geffen School of Medicine and Attending Consultant of the Endocrine Clinic at the West Los Angeles VA Medical Center in California. A well known and beloved member of the "thyroid community" who has published over 500 papers and reviews, he readily agreed to talk with us about his life and career as he approached his 89th birthday.
Quantum caustics and chaos in continuously measured quantum systems

Measured quantum systems exhibit their own form of dynamics that is stochastic and nonunitary. Of particular interest are the most likely paths in quantum space between two boundary conditions in a certain time. I will show how caustic structures can arise in these paths, and predict the occurrence of chaos. In the former case, comparison with experiments on superconducting quantum circuits will be given.
LGBTQ+ health research guides at North American health sciences libraries: a survey and content analysis

Objectives: Current literature recommends online research guides as an easy and effective tool to promote LGBTQ+ health information to both health care providers and the public. This cross-sectional study was designed to determine how extensive LGBTQ+ health guides are among hospital and academic libraries and which features are most prevalent. Methods: In order to locate LGBTQ+ health guides for content analysis, we searched for guides on the websites of libraries belonging to the Association of Academic Health Sciences Libraries (AAHSL) and the Canadian Association of Research Libraries (CARL). Additionally, we searched the Springshare interface for LibGuides with the word “health” and either “LGBT” or “transgender.” Content analysis was performed to identify major characteristics of the located guides, including target audience and the information type provided. Results: LGBTQ+ research guides were identified for 74 libraries. Of these, 5 were hospital libraries, and the rest were academic libraries. Of 158 AAHSL member libraries, 48 (30.4%) had LGBTQ+ guides on their websites. Nearly all guides (95.9%) provided general LGBTQ+ health information, and a large majority (87.8%) also had information resources for transgender health. Smaller percentages of guides contained information on HIV/AIDS (48.6%) and women’s health (16.2%). Conclusions: Even though literature recommends creating LGBTQ+ health guides, most health sciences libraries are missing an opportunity by not developing and maintaining these guides. Further research may be needed to determine the usage and usefulness of existing guides and to better identify barriers preventing libraries from creating guides.
Maintaining atomically smooth GaAs surfaces after high-temperature processing for precise interdiffusion analysis and materials engineering

Arsenic's high vapor pressure leads to thermal instability during high-temperature processing (>370 °C) of GaAs, contributing to the performance degradation of subsequently fabricated devices. The resulting surface damage also obfuscates the exact quantitative characterization of the diffusion process, a critical step in device manufacturing. In this experiment, an encapsulant-and-sacrificial-layer procedure is employed to reduce arsenic sublimation and preserve a smooth surface. A capped GaAs/InGaAs/GaAs quantum well structure is subjected to rapid thermal annealing, and AFM, SEM, and energy-dispersive x-ray spectroscopy are used to compare the surface qualities of the postannealed encapsulated GaAs against the reference GaAs. For the encapsulated substrate, a smooth surface with an average root-mean-squared value of 6.5 A is achieved after high-temperature processing. SIMS analysis is used to obtain the diffused indium atomic concentration profiles for a smooth and roughened GaAs surface and their corresponding diffusion parameters. The interdiffusion characterization process demonstrates in a GaAs/InGaAs system how precise diffusion parameter extraction requires preserving an atomically smooth surface when using surface-sensitive techniques.
Competitive Coadsorption of CO2 with H2O, NH3, SO2, NO, NO2, N2, O2, and CH4 in M-MOF-74 (M = Mg, Co, Ni): The Role of Hydrogen Bonding

The importance of coadsorption for applications of porous materials in gas separation has motivated fundamental studies, which have initially focused on the comparison of the binding energies of different gas molecules in the pores (i.e., energetics) and their overall transport. By examining the competitive coadsorption of several small molecules in M-MOF-74 (M = Mg, Co, Ni) with in situ infrared spectroscopy and ab initio simulations, we find that the binding energy at the most favorable (metal) site is not a sufficient indicator for prediction of molecular adsorption and stability in MOFs. Instead, the occupation of the open metal sites is governed by kinetics, whereby the interaction of the guest molecules with the MOF organic linkers controls the reaction barrier for molecular exchange. Specifically, the displacement of CO2 adsorbed at the metal center by other molecules such as H2O, NH3, SO2, NO, NO2, N2, O2, and CH4 is mainly observed for H2O and NH3, even though SO2, NO, and NO2 have higher binding...
Using Latent Class Analysis to Set Academic Performance Standards

This study investigated using latent class analysis to set performance standards for assessments comprised of multiple-choice and performance assessment items. Employing this procedure, it is possible to use a sample of student responses to accomplish four goals: (a) determine how well a specified latent structure fits student performance data; (b) determine which latent structure best represents the relationships in the data; (c) obtain estimates of item parameters for each latent class; and (d) identify to which class within that latent structure each response pattern most likely belongs. Comparisons with the Angoff and profile rating methods revealed that the approaches agreed with each other quite well, indicating that both empirical and test-based judgmental approaches may be used for setting performance standards for student achievement.
Optical Absorption Spectra of Cr3+ in MgO·Al2O3‐MgO·3.5Al2O3 Spinels

Spinel crystals in the system MgO·nAl2O3:Cr3+ (1.04≤n≤3.51) were synthesized by flame fusion; their absorption spectra were measured in transmission from 400 to 50,000 cm−1. The O-H band spectra suggest the presence of protons in octahedral site vacancies which appear for n>1. The spectra for Cr3+ indicate clearly that these ions occupy only octahedral sites. However, the effective trigonal field, which varies with n, causes the major absorption bands to split in the form of a lower-energy shoulder on a higher-energy component. The red-green transition in these spinels was rationalized and observed to arise from a somewhat different mechanism than that in other oxides in which the site radii and Cr3+ concentration vary considerably.
Imitate Others? Not if We Have the Chance: Competitive Differentiation in Medical Malpractice Insurers' Pricing Decisions under Uncertainty

Several perspectives assert that organizations facing uncertainty tend to imitate other organizations' actions. While one might therefore expect to see great homogeneity across fields characterized by uncertainty, it is surprising that this homogeneity has not been observed more frequently in practice. Research investigating this puzzle has typically focused on the role played by organizational characteristics or the information organizations possess about their environments. Instead, this study turns attention to the information others possess about the organization. To that end, I disaggregate organizational uncertainty into the uncertainty facing decision makers and the uncertainty faced by others about what those decision makers might ultimately do, providing a more fine grained analysis of uncertainty and its impact on competitive action than typically offered in this literature. I suggest that uncertainty in competitors' evaluations of the organization provides an opportunity for the organization to differentiate itself rather than imitate others. I also suggest that this effect is stronger than the effects of the uncertainty facing the decision makers themselves. Related hypotheses are tested on a panel of medical malpractice insurance providers. The study's perspective generates unique predictions regarding imitation and differentiation in this industry and across other contexts featuring both uncertainty and competition.
Contradictions and Limits of a Developmental State: With Illustrations from the South Korean Case

Studies of the rapid rise of East Asian nations in the world economy have focused on the “strong” and “developmental” state, documenting the foundations of the rise of the state and its remarkable achievements. Absent from these studies has been analysis of how the state changed as a result of development, the causes of change, and the actors involved in this transition. This study focuses on the case of South Korea, where the state's influence in the economy declined due to historical pressures and the inherent contradictions of autonomy and institution. The paradox of South Korea s remarkable success in development was that it forced the state to reevaluate its raison d'etre and to curtail its functions. The weakening developmental state is presented with unusual challenges when a more dramatic breakdown of the authoritarian regime and ensuing democratic consolidation occur. The former process is subsumed under broader, sweeping political reforms, and the political environment of democracy makes it difficult for the state to choose between the capitalists' demand for a protectionist government and labor's demand for a welfare state.
Selective axonal transport of anthracycline antibiotics.

Abstract The retrograde intraaxonal transport of several anthracycline antibiotics was assessed in the peripheral nervous system of adult mice. Despite certain chemical similarities, the intraaxonal transport of these molecules was variable and could be correlated with the structure of the aminosugar at the R-2 position. One particularly interesting compound, 4′-deoxydoxorubicin, was transported by dorsal root ganglia axons, but not by the axons of ventral horn neurons. These observations suggest that the sugar component of a molecule may be important for its intraaxonal transport in the peripheral nervous system.
Structural studies by NMR spectroscopy of the major oligomers from alkali-degraded arabinoigalactan from Larix occidentalis

Abstract Oligomers with terminal metasaccharinic acid residues have been derived from branches on the main chain of arabinogalactan by alkaline degradation. The major oligomers present have been studied by NMR. Individual oligomers existed as epimeric pairs in the approximate ratio 1.5:1. This study confirmed the presence of branches consisting of a single β- d -Ga1p residue, of two or three β- d -Galp residues linked (1→6) or of two β-D-Ga1p residues linked (1→6) with the proximate residue further substituted at O-3 by an α- L -arabinofuranosyl residue.
Magnetic Resonance Imaging of Therapy-Induced Necrosis Using Gadolinium-Chelated Polyglutamic Acids

Purpose: Necrosis is the most common morphologic alteration found in tumors and surrounding normal tissues after radiation therapy or chemotherapy. Accurate measurement of necrosis may provide an early indication of treatment efficacy or associated toxicity. The purpose of this report is to evaluate the selective accumulation of polymeric paramagnetic magnetic resonance (MR) contrast agents—gadolinium p-aminobenzyl-diethylenetriaminepentaacetic acid-poly(glutamic acid) (L-PG-DTPA-Gd and D-PG-DTPA-Gd)—in necrotic tissue. Methods and Materials: Two different solid tumor models, human Colo-205 xenograft and syngeneic murine OCA-1 ovarian tumors, were used in this study. Necrotic response was induced by treatment with poly(L-glutamic acid)-paclitaxel conjugate (PG-TXL). T1-weighted spin-echo images were obtained immediately and up to 4 days after contrast injection and compared with corresponding histologic specimens. Two low-molecular-weight contrast agents, DTPA-Gd and oligomeric(L-glutamic acid)-DTPA-Gd, were used as nonspecific controls. Results: Initially, there was minimal tumor enhancement after injection of either L-PG-DTPA-Gd or D-PG-DTPA-Gd, but rapid enhancement after injection of low-molecular-weight agents. However, polymeric contrast agents, but not low-molecular-weight contrast agents, caused sustained enhancement in regions of tumor necrosis in both tumors treated with PG-TXL and untreated tumors. These data indicate that high molecular weight, rather than in vivo biodegradation, is necessary for the specific localization of polymeric MR contrast agents to necrotic tissue. Moreover, biotinylated L-PG-DTPA-Gd colocalized with macrophages in the tumor necrotic areas, suggesting that selective accumulation of L- and D-PG-DTPA-Gd in necrotic tissue was mediated through residing macrophages. Conclusions: Our data suggest that MR imaging with PG-DTPA-Gd may be a useful technique for noninvasive characterization of treatment-induced necrosis.
Use of Otolith Microstructure to Discriminate Stocks of Juvenile Central Valley, California, Fall-Run Chinook Salmon

Abstract We examined the utility of otolith microstructure analysis as a means of discriminating among stocks and between rearing types of juvenile fall-run Chinook salmon Oncorhynchus tshawytscha in California's Central Valley. Otolith samples were collected from 11 geographically discrete stocks of fall-run Chinook salmon of river and hatchery rearing types over 2 years. Six measured otolith attributes and three statistics derived from these measurements served as dependent variables in a multifactor analysis of variance of paired river and hatchery stocks. Morphometrics that demonstrated no significant interaction between year and stock or rearing type were used as predictors in discriminant function analyses; 32% of samples were correctly classified by stock and 80% were correctly classified by rearing type. Measures of otolith size at fry emergence were the best predictors for distinguishing among both stocks and rearing types with discriminant function analysis. We hypothesize that observed differen...
NOAA's New Office of Marine Minerals

A new Office of Marine Minerals has been established in the Department of Commerce's National Oceanic & Atmospheric Administration (NOAA). The new office serves as a focal point for NOAA's new and expanding programs in marine minerals. It also has planning, coordinating and certain operational responsibilities. During the past year the new office has initiated various plans and studies. An important example in environmental assessment involves the development of a plan for a multi-phased "Assessment of Environmental and Socio-Economic Impacts of Onshore Processing Activities Associated with Deep Ocean Mining" in response to Congressional request and concerns of others. A contract on the first phase has already been awarded. One of the major areas of involvement was in determining national needs in marine minerals. A major workshop was convened in Silver Spring, Maryland in early 1976 to review past and present NOAA activities in marine minerals including those conducted by the Marine Minerals Technology Center (MMTC) and Sea Grant and to assess future national needs. Approximately eighty persons from academia, industry, government and NOAA participated. This is the first time such a widely based marine minerals workshop was ever held. This paper will also review some of the highlights of this meeting held in Silver Spring.
Small Molecule Analogs of Phospholipid-Metal Ion Binding Sites: Synthesis and Molecular Modeling of Cyclohexane-1,2,4-triol Trisphosphates

Abstract Four diastereomeric cyclohexane-1,2,4-triol trisphosphates were synthesized to serve as small molecule analogs of putative phospholipid-metal ion binding sites. The parent cyclehexane-1,2,4-triols were prepared and phosphorylated. Deprotection of the tris(diphenylphosphates) provided four regiochemical isomers: two with the trans -1,2-phosphate moiety, (±)-(1 R ,2 R ,4 S )- and (±)-(1 R ,2 R ,4 R )-cyclohexane-1,2,4-triol tris(ammonium hydrogen phosphate), and two with the cis -1,2-phosphate moiety, (±)-(1 R ,2 S ,4 R )- and (±)-(1R,2S, 4S)-cyclohexane-1,2,4-triol tris(ammonium hydrogen phosphate). Molecular mechanics calculations for each trisphosphate and the Ca(II) and Mg(II) complex were performed using MacroModel. Results from the molecular modeling studies indicate that two of the criteria for the suitability of the trisphosphates as analogs of phospholipid-metal ion binding sites are satisfied: (1) anionic groups which can interactively bind a metal ion and (2) interphosphate distances comparable to the phosphate-phosphate distances of a computational phospholipid surface.
CONFORMATIONS AND MUTAROTATIONS OF POLY(5-METHYL-L-PROLINE)

Optically active poly( cis -5-methyl-L-proline) and poly( trans -5-methyl-L-proline) were synthesized from their respective N-carboxy-anhydrides (NCA). Analysis of the i.r., u.v., n.m.r., ORD, and CD spectra of the polymers showed that two different conformations of each polymer exist in the solid and in solution in appropriate solvents. Form I and form II of poly( trans -5-methyl-L-proline) were found to have the same conformations as the form I and form II of poly-L-proline, respectively. Form B of poly( cis -5-methyl-L-proline) seemed to have a somewhat different conformation from form II of poly-L-proline. The changes in viscosity during the mutarotations of the two polymers showed that the mutarotation entailed cis-trans isomerization of amide bonds in the polymers. By following the kinetics of the mutarotations it was found that the activation energies for poly( cis -5-methyl-L-proline) was 22 kcal per residue mole, whereas E a of poly( trans -5-methyl-L-proline) was 33 kcal per residue mole. The excess 10 kcal for the latter polymer was attributed partially to the steric barrier between the methyl group at the trans -5-position and the carbonyl group in the polymer.
Guided Axon Growth by Gradients of Adhesion in Collagen Gels

During development, neurites are directed by gradients of attractive and repulsive soluble (chemotactic) cues and substrate-bound adhesive (haptotactic) cues. Many of these cues have been extensively researched in vitro, and incorporated into strategies for nerve and spinal cord regeneration, primarily to improve the regenerative environment. To enhance and direct growth, we have developed a system to create 1D gradients of adhesion through a 3D collagen gel using microfluidics. We test our system using collagen grafted with bioactive peptide sequences, IKVAV and YIGSR, from laminin — an extra-cellular matrix (ECM) protein known to strongly influence neurite outgrowth. Gradients are established from ∼0.37mg peptide/mg collagen – 0, and ∼0.18 mg peptide/mg collagen – 0 of each peptide and tested using chick dorsal root ganglia (DRG). Neurite growth is evaluated 5 days after gradient formation. Neurites show increased growth in the gradient system when compared to control and biased growth up the gradient of peptides. Growth in YIGSR-grafted collagen increased with steeper gradients, whereas growth in IKVAV-grafted collagen decreased with steeper gradients. These results demonstrate that neurite growth can be enhanced and directed by controlled, immobilized, haptotactic gradients through 3D scaffolds, and suggest that including these gradients in regenerative therapies may accelerate nerve and spinal cord regeneration.Copyright © 2008 by ASME
Regulatory Light Chain Mutants Linked to Heart Disease Modify the Cardiac Myosin Lever Arm

Myosin is the chemomechanical energy transducer in striated heart muscle. The myosin cross-bridge applies impulsive force to actin while consuming ATP chemical energy to propel myosin thick filaments relative to actin thin filaments in the fiber. Transduction begins with ATP hydrolysis in the cross-bridge driving rotary movement of a lever arm converting torque into linear displacement. Myosin regulatory light chain (RLC) binds to the lever arm and modifies its ability to translate actin. Gene sequencing implicated several RLC mutations in heart disease, and three of them are investigated here using photoactivatable GFP-tagged RLC (RLC-PAGFP) exchanged into permeabilized papillary muscle fibers. A single-lever arm probe orientation is detected in the crowded environment of the muscle fiber by using RLC-PAGFP with dipole orientation deduced from the three-spatial dimension fluorescence emission pattern of the single molecule. Symmetry and selection rules locate dipoles in their half-sarcomere, identify those at the minimal free energy, and specify active dipole contraction intermediates. Experiments were performed in a microfluidic chamber designed for isometric contraction, total internal reflection fluorescence detection, and two-photon excitation second harmonic generation to evaluate sarcomere length. The RLC-PAGFP reports apparently discretized lever arm orientation intermediates in active isometric fibers that on average produce the stall force. Disease-linked mutants introduced into RLC move intermediate occupancy further down the free energy gradient, implying lever arms rotate more to reach stall force because mutant RLC increases lever arm shear strain. A lower free energy intermediate occupancy involves a lower energy conversion efficiency in the fiber relating a specific myosin function modification to the disease-implicated mutant.
Committee choice and the core under supramajority rule: Results from simulation of majority choice in 2-dimensional space

While simple-majority choice by committees is generally unstable, supramajority rule has been demonstrated to yield nonempty sets of stable outcomes: outcomes in the core. This paper reports results of a computer simulation of majority choice by committees under supramajority rule. The object is to explore the transition from unstable to stable committee choice with increasing supramajority rules.
Ethanol effects on synaptic neurotransmission and tetanus-induced synaptic plasticity in hippocampal slices of chronic in vivo lead-exposed adult rats.

Abstract The interaction of chronic in vivo lead exposure and acute in vitro ethanol treatment on synaptic neurotransmission and plasticity were studied using extracellular electrophysiological techniques in CAI region of hippocampal brain slices from adult rats. Neither chronic lead exposure nor acute ethanol treatment had any significant effect on field excitatory postsynaptic potentials (EPSPs). In vivo lead exposure enhanced short-term potentiation (STP, potentiation that decays within 30 min) by 21% shortly after ‘weak’ tetanus, but had no effect on long-term potentiation (LTP, sustained at least 1 h). In vitro bath application of 60 mM ethanol inhibited STP by 35% and blocked LTP induced by ‘weak’ tetanus in slices from Pb-exposed rats (500 ppm lead acetate, 56–70 days), while having no effect on STP or LTP in slices from control counterpart Na-exposed rats (pair-fed 216 ppm sodium acetate). In contrast, `strong'-tetanus-induced LTP was abolished in Pb-exposed slices, and 60 mM ethanol slightly inhibited STP and blocked LTP in slices from Na-exposed rats. These differences could not be explained by differences in ethanol inhibition of NMDA-mediated field EPSPs because they were similarly reduced in slices from Na-exposed (30%) and Pb-exposed (25%) rats. These findings suggest that the strength of the tetanus used determines whether or not synaptic plasticity is blocked by either chronic lead exposure or acute ethanol treatment, and that even in adult rats, hippocampal synaptic LTP can be compromised by combined exposure to ethanol and lead. More importantly, these findings suggest the consequences of combined lead exposure and alcohol abuse in the adult human population may not be fully recognized yet.
The impact of synchrotron radiation on nanoscience

We shall review the various methods, which are currently in use or planned for the characterization of the structure and dynamics of nanostructured materials. These include X-ray microscopy, microdiffraction, imaging and X-ray scattering. Examples will be presented of nanostructured systems of interest where such studies are being used to study the effects of nanoconfinement in one, two and three dimensions. These include magnetic films, magnetic dots, quantum wells, nanowires, etc.
Empirical studies on agricultural impacts and adaptation

Agricultural production is heavily dependent on weather outcomes, and hence climate change has the potential to significantly alter the sector's productivity. Both reduced form studies as well as integrated assessment models have found that the agricultural sector might experience significant impacts. We discuss the advantages of empirical reduced-form studies and their link and potential usefulness to integrated assessment models. We further discuss challenges facing empirical studies and recent research that looks at the longer term changes in climate and attempts to measure adaptation.
Particle diffusivities and deposition velocities over a horizontal smooth surface

Abstract Particle effective eddy diffusion coefficients, ϵ/ν, [(inertial + diffusion)/viscous forces], were calculated from experimental deposition fluxes to a smooth horizontal surface. The ϵ/ν are a function of both particle inertia (τ+), the distance from the surface (y+), and the air friction velocity ( u ∗ ) which is contained in both dimensionless terms. These ϵ/ν are greater than the ϵ/ν for particle deposition along a vertical surface. Both correlations show that particle effective eddy diffusion coefficients are much greater than the eddy diffusion of air momentum for distances from the surface of y+ 350. These ϵ/ν are similar to those for air momentum transfer. The effective eddy diffusivities are combined with Brownian diffusion and gravity settling to predict particle deposition velocities for particle size from 10−3 to 102 μm diameter for particle densities of 1 and 10 gm/cm3. Each of these mechanisms of particle transport controls the predicted deposition in some range of particle size. The deposition velocities show minima of 1.8 × 10−4 to 7.7 × 10−3 cm/sec for particle sizes from 0.066 to 0.54 μm. The minima as well as all deposition velocities are equal to or much greater than predicted from gravitational settling.
Electrodeless Discharges at High Frequencies and Low Pressures

In the last ten years electrodeless discharges have become increasingly important to the spectroscopist as light sources that possess distinct advantages over d.c. discharge tubes. An attempt was made to gather information on the characteristics of such discharges at frequencies of 10, 15, 20, and 25 megacycles and pressures ranging from 10−2 to 10−4 mm of Hg using dry air as the filling gas. It is hoped that the data presented here in form of onset and offset potentials versus pressure will help the spectroscopist in the design of his light sources and of the associated electrical equipment, thus taking this aspect of his research at least partly out of the realm of trial and error.—With this as our primary objective the experimental conditions were not appropriate for yielding data that contribute to the understanding of the fundamental mechanisms of such discharges. Therefore a detailed discussion of the shapes of the characteristic curves Vsversusp is omitted.
Chinmo and Neuroblast Temporal Identity

Although spatial patterning during embryonic development is well characterized, a corresponding framework for temporal patterning has not been established. In this issue, Zhu et al. (2006) identify the Chinmo protein as conferring temporal identity on the neural progeny of Drosophila neuroblasts, revealing appealing parallels with spatial patterning.
Disturbance rejection and tracking using output feedforward control

The disturbance rejection and tracking problems that have particularly nice solutions when full state feedback is used are discussed. Although the output feedback problem, in general, has a very difficult solution, it is seen that for these special cases, the solution involves solving only a linear two-point boundary-value problem, rather than the nonlinear problem associated with the general case. The Kronecker algebra is of considerable usefulness in obtaining the solution, which involves a matrix linear two-point boundary-value problem. The solution has applications in the area of large-scale systems where one may consider the disturbance to be the interconnection vector which reflects how the other states of a large system affect the local dynamical model. >
A retrospective cohort study of perioperative management on the morbidity of urogynecologic surgery

To determine whether premenopausal and early (<70) and late postmenopausal women whose comorbidities were screened and managed using a standardized protocol experienced comparable perioperative complications after urogynecologic surgery. We retrospectively reviewed the charts of all women who presented for surgical management of their pelvic floor disorders over 4.5 years for any complications, which occurred intraoperatively to 6 weeks postoperatively. Late postmenopausal women underwent more vaginal (100/124, 159/246, and 226/288, p < 0.001) and obliterative (15/124, 0/246, and 4/288, p < 0.001), and fewer abdominal (9/124, 87/246, and 58/288, p < 0.001) procedures and had lower body mass index (27.1, 31.4, and 29.4, P < 0.001) and fewer smokers (4/124, 86/246, and 52/288, p < 0.001) than premenopausal and early postmenopausal subjects. After adjusting for these differences, the proportions that experienced perioperative complications were similar among the three groups (P = 0.789). With standardized screening and management, our premenopausal and early and late postmenopausal women experienced similar perioperative complications.
Effect of Modafinil on Impairments in Neurobehavioral Performance and Learning Associated with Extended Wakefulness and Circadian Misalignment

Although worldwide millions of people work prolonged hours, at adverse circadian phases, evidence suggests that cognitive function is impaired under these conditions with important societal consequences. In a double-blind placebo-controlled laboratory-based study, we investigated the effect of the wakefulness-promoting drug modafinil as a countermeasure against such neurobehavioral impairments induced by both prolonged wakefulness and circadian misalignment. Neurobehavioral performance, alertness, and sleep were studied in young healthy participants (N=18) who underwent a 25-day forced desynchrony protocol in which the period of the sleep-wakefulness cycle was scheduled to be 42.85 h (duration of each wakefulness episode: 28.57 h; sleep/rest episode: 14.28 h). Each waking day, participants were treated with either 400 mg modafinil, divided into three doses, or placebo, according to a randomized, parallel-group design. Treatment with modafinil significantly attenuated the performance decrements seen for several parameters including cognitive-psychomotor speed, visual attention and reaction times both with progressive hours awake and when working at adverse circadian phases. Subjective alertness and sleep parameters were similar between treatment groups, but modafinil-treated participants had fewer bouts of inadvertent sleep during scheduled waking. Modafinil reduced the neurobehavioral impairment associated with work, both during prolonged wakefulness and at adverse circadian phases, without adversely affecting subjective alertness or subsequent sleep. These features suggest that modafinil might be a particularly relevant countermeasure against the deleterious effects of prolonged work hours, shift work, and transmeridian travel.
Power, change, and gender relations in rural Java : a tale of two villages

Women's status in rural Java can appear contradictory to those both inside and outside the culture. In some ways, women have high status and broad access to resources, but other situations suggest that Javanese women lack real power and autonomy. Javanese women have major responsibilities in supporting their families and controlling household finances. They may also own and manage their own property. Yet these symbols and potential sources of independence and influence are determined by a culturally prescribed, state-reinforced, patriarchal gender ideology that limits women's autonomy. Power, Change, and Gender Relations in Rural Java examines this contradiction as well as sources of stability and change in contemporary Javanese gender relations. The authors conducted their research in two rural villages in Yogyakarta, Indonesia, during three important historical and political periods: the end of the New Order regime; the transitional period of reformation; and the subsequent establishment of a democratic government. Their collaboration brings a unique perspective, analyzing how gender is constructed and reproduced and how power is exercised as Indonesia faces the challenges of building a new social order.
The Intramolecular Loss of Fluorescence by Lysine Derivatized with Naphthalenedialdehyde

Derivatization of primary amines such as amino acids and peptides with naphthalenedialdehyde (NDA) in the presence of cyanide ion yields cyanobenzo[f]-isoindole (CBI) adducts that are highly fluorescent. However, the fluorescence is seriously quenched with amines that possess more than one primary amine site, as is the case with lysine. Although it was found that the adsorption of CBI2-lysine on a solid substrate restored the fluorescence, the reason for the solution quenching, with respect to results for mono-derivatized amines, was investigated. The experiments to probe the quenching were based on the assumption that the mechanism responsible for quenching involved a charge-transfer (CT) excited state. Thus, it was found that the solvent properties of viscosity and polarity affected the lifetime and quantum yield of fluorescence in a manner consistent with the proposed mechanism.
Crystal-melt and melt-vapor interfaces of nickel

The equilibrium crystal-to-melt interfaces for Ni(001) and Ni(111) and themelt-to-vapor interface are investigated at the melting point, with use ofmolecular-dynamics simulations and the embedded-atom method. The meltingtemperature of nickel determined from these simulations is1733+-22 K, in good agreement with the experimental value.The crystal-to-melt interface is found to be characterized by liquid layering,with properties such as structural order parameters and diffusion coefficientsvarying gradually across the transition region. The transition region extendsover several layers and is more diffuse at the (001) interface. At themelt-to-vapor interface the density increases, driven by an increase in themagnitude of the density-dependent embedding-energy contribution to thecohesive energy of the metal. This behavior is in contrast to that found at themelt-to-vapor interface of nonmetallic systems.
CONTINUOUS FLOW METHOD FOR MONITORING PROTEIN PRECIPITATION BY AMMONIUM SULFATE

I have proposed “Centrifugal Precipitation Chromatography”[1] as a new method for the precipitation of proteins using a linear gradient of ammonium sulfate (AS). However data on the solubility of proteins under these specific conditions are not available. Therefore, the following method is proposed to obtain these data. It uses an HPLC pump to form a linear concentration gradient between a protein solution and a concentrated ammonium sulfate (AS) solution (90% saturation) which is continuously monitored with a uv detector at 280 nm. At a low flow rate of 0.1 mL/min the protein is exposed to a gradually increasing AS concentration until it reaches the critical point where precipitation takes place. The resulting light scattering increases the absorbance reading to form a distinct peak on the uv gradient curve where the valley and summit of the peak correspond to the starting and ending points of the protein precipitation, respectively. The method has been tested with a set of stable proteins at various pHs...