cssi/SciSciGPT-SciSciNet huggingface dataset:
Surgical Versus Percutaneous Approaches for Degenerative Mitral Valve Repair: A Review

ABSTRACTThere is a wide range of pathologies to account for severe degenerative mitral regurgitation. Mitral valve repair has proven superior to replacement in the treatment of degenerative mitral ...
It Takes a Village to Grow a Person: A Case of a Psychoanalytic Treatment in a Hospital Setting

In today’s culture of evidence-based treatment and managed care, psychoanalysis is mostly relegated to the private consulting rooms of psychoanalysts, no longer available in hospital settings for t...
Differences in the constituent fiber types contribute to the intermuscular variation in the timing of the developmental synapse elimination

The emergence of a mature nervous system requires a significant refinement of the synaptic connections initially formed during development. Redundant synaptic connections are removed in a process known as synapse elimination. Synapse elimination has been extensively studied at the rodent neuromuscular junction (NMJ). Although several axons initially converge onto each postsynaptic muscle fiber, all redundant inputs are removed during early postnatal development until a single motor neuron innervates each NMJ. Neuronal activity as well as synaptic glia influence the course of synapse elimination. It is, however, unclear whether target muscle fibers are more than naive substrates in this process. I examined the influence of target myofiber contractile properties on synapse elimination. The timing of redundant input removal in muscles examined correlates strongly with their proportion of slow myofibers: muscles with more slow fibers undergo elimination more slowly. Moreover, this intermuscular difference in the timing of synapse elimination appears to result from local differences in the rate of elimination on fast versus slow myofibers. These results, therefore, imply that differences in the constituent fiber types help account for the variation in the timing of the developmental synapse elimination between muscles and show that the muscle plays a role in the process.
Personalizing with Human Cognitive Biases

Human cognitive biases are numerous and well established. Due to inherent limitations in our knowledge of the world, and computational constraints, our judgments and decisions do not rigidly adhere to the principle of maximizing expected utility. We frequently employ cognitive shortcuts, ignoring relevant information, and make errors in how we store and retrieve items from memory. Human decisions are additionally influenced by moral, emotional and cultural parameters. People often perceive value in a way that is very different from well-established decision-theoretic frameworks, but much of the work on personalization does not capture human cognitive biases. Our central hypothesis is that a new generation of recommendation systems can be designed by explicitly modeling human cognitive biases such as contrast, decoy, distinction, and framing. We are just now beginning to see explicit non-linear models of human risk perception being incorporated into machine learning algorithms, and we believe this trend will accelerate in the near future. In this paper we review today's recommendation systems, give an analysis of their limitations and make an argument for why future recommendation systems should incorporate explicit models of human cognitive bias.
Interdisciplinary travel courses - creating magical experiences

I describe here the development of a travel experience made up of two courses designed to pair up Physics and Computer Science students. The students, after a semester of research and study, were placed into teams and asked to design an attraction suitable for use in a major theme park. Course development, expectations and outcomes, travel planning, and a description of the travel experience are discussed herein.
Genetic deletion of Urocortin 3 does not prevent functional maturation of beta cells

There is great interest in generating functionally mature beta cells from stem cells, as loss of functional beta cell mass contributes to the pathophysiology of diabetes. Identifying markers of beta cell maturity is therefore very helpful for distinguishing stem cells that have been successfully differentiated into fully mature beta cells from stem cells that did not. Urocortin 3 (UCN3) is a peptide hormone whose expression is associated with the acquisition of functional maturity in beta cells. The onset of its expression occurs after other beta cell maturity markers are already expressed and its loss marks the beginning of beta cell dedifferentiation. Its expression pattern is therefore tightly correlated with beta cell maturity. While this makes UCN3 an excellent marker of beta cell maturity, it is not established whether UCN3 is required for beta cell maturation. Here, we compared gene expression and function of beta cells from Ucn3-null mice relative to WT mice to determine whether beta cells are functionally mature in the absence of UCN3. Our results show that genetic deletion of Ucn3 does not cause a loss of beta cell maturity or an increase in beta cell dedifferentiation. Furthermore, virgin beta cells, first identified as insulin-expressing, UCN3-negative beta cells, can still be detected at the islet periphery in Ucn3-null mice. Beta cells from Ucn3-null mice also exhibit normal calcium response when exposed to high glucose. Collectively, these observations indicate that UCN3 is an excellent mature beta cell marker that is nevertheless not necessary for beta cell maturation.
The impact of tumor NGS testing on hereditary cancer risk assessment and population management in an integrated community health care system.

1517Background: Next-generation sequencing (NGS) for tumor molecular profiling is used in Oncology to identify ‘actionable alterations’ for clinical trials or on/ off-label therapy. Tumor NGS can a...
Linking isotope analysis and paleopathology: An andean perspective

This paper reviews the significant advances in isotopic investigations in Andean South America and directs scholars to explore new theoretical and analytical directions, specifically the applicability of isotope data to paleopathology. Excellent preservation and large skeletal collections of human remains make the Central Andes ideal for biogeochemical reconstructions and advancements in isotopic methods. Our aims are twofold: first, we present a meta-analysis of stable and radiogenic isotope research in the Central Andes since 1985, and highlight those that combine analyses of isotope ratios and pathological conditions. Second, we discuss useful directions for incorporating stable isotope analysis more explicitly in studies of paleopathology in the Andes more in the future. Principle research foci have described dietary variation and regional population mobility since the 1980s, where early methodological explorations identified significant trends in isotopic variation. For the years 1980-2017, we identified 96 scholarly publications through a meta-data analysis of major peer-reviewed journals, book chapters, and conference proceedings. These demonstrate specific trends in topical and methodological preferences across the Andean region and a shift from 10 publications pre-1997 to 67 in the last 10 years. However, combined isotope and paleopathology studies in this region remain sparse; given the ecological, geological, and cultural complexity of the Central Andes, analyses of pathological conditions in different regions would significantly benefit from the information on diet, mobility, and local ecology that isotope ratios provide. Isotope analysis requires destruction of archaeological tissues, and interpreting isotope data can be complex, but it can also provide unique insights into the pathogenesis of multifactorial conditions and assist differential diagnosis. Therefore, we also discuss research designs for pairing isotopic and paleopathological variables that will allow researchers to better capture disease ecologies in archaeological samples and their variation across different regions, within related sites, and within individual lifespans.
Keepers of the comments: How comment moderators handle audience contributions:

As news commenting has evolved as a participatory tool and journalists have developed traditional practices for moderation, there are questions about how to promote quality spaces for news discours...
Clinical Translation of an Insertion Tool for Minimally Invasive Cochlear Implant Surgery.

The objective of this paper is to describe the development of a minimally invasive cochlear implant surgery (MICIS) electrode array insertion tool concept to enable clinical translation. First, analysis of the geometric parameters of potential MICIS patients (N = 97) was performed to inform tool design, inform MICIS phantom model design, and provide further insight into MICIS candidacy. Design changes were made to the insertion tool based on clinical requirements and parameter analysis results. A MICIS phantom testing model was built to evaluate insertion force profiles in a clinically realistic manner, and the new tool design was evaluated in the model and in cadavers to test clinical viability. Finally, after regulatory approval, the tool was used for the first time in a clinical case. Results of this work included first, in the parameter analysis, approximately 20% of the population was not considered viable MICIS candidates. Additionally, one 3D printed tool could accommodate all viable candidates with polyimide sheath length adjustments accounting for interpatient variation. The insertion tool design was miniaturized out of clinical necessity and a disassembly method, necessary for removal around the cochlear implant, was developed and tested. Phantom model testing revealed that the force profile of the insertion tool was similar to that of traditional forceps insertion. Cadaver testing demonstrated that all clinical requirements (including complete disassembly) were achieved with the tool, and the new tool enabled 15% deeper insertions compared to the forceps approach. Finally, and most importantly, the tool helped achieve a full insertion in its first MICIS clinical case. In conclusion, the new insertion tool provides a clinically viable solution to one of the most difficult aspects of MICIS.
Meta-analysis of AKI to CKD transition in perioperative patients.

BACKGROUND Recent research shows AKI increases the risk of incident CKD. We hypothesized that perioperative AKI may confer increased risk of subsequent CKD compared to nonperioperative AKI. METHODS A MEDLINE search was performed for "AKI, CKD, chronic renal insufficiency, surgery, and perioperative" and related terms yielded 5209 articles. One thousand sixty-five relevant studies were reviewed. One thousand six were excluded because they were review, animal, or pediatric studies. Fifty-nine studies underwent full manuscript review by two independent evaluators. Seventeen met all inclusion criteria and underwent analysis. Two-by-two tables were constructed from AKI +/- and CKD +/- data. The R package metafor was employed to determine odds ratio (OR), and a random-effects model was used to calculate weighted ORs. Leave-1-out, funnel analysis, and structured analysis were used to estimate effects of study heterogeneity and bias. RESULTS Nonperioperative studies included studies of oncology, percutaneous coronary intervention, and myocardial infarction patients. Perioperative studies comprised patients from cardiac surgery, vascular surgery, and burns. There was significant heterogeneity, but risk of bias was overall assessed as low. The OR for AKI versus non-AKI patients developing CKD in all studies was 4.31 (95% CI 3.01-6.17; p < 0.01). Nonperioperative subjects demonstrated OR 3.32 for developing CKD compared to non-AKI patients (95% CI 2.06-5.34; p < 0.01) while perioperative patients demonstrated OR 5.20 (95% CI 3.12-8.66; p < 0.01) for the same event. CONCLUSIONS We conclude that studies conducted in perioperative and nonperioperative patient populations suggest similar risk of development of CKD after AKI.
HIV and the Kidney

Human immunodeficiency virus (HIV) infection, now a worldwide phenomenon has seen remarkable therapeutic advances in the last few decades. As people live longer with HIV, the long-term effects of the disease are emerging. One such condition is HIV-related renal disease. HIV-associated nephropathy was common in perinatally-infected children in the pre-anti-retroviral era. However, in the current scenario when highly active antiretroviral therapy (HAART) is widely used, HIV-associated renal disease is being identified in more children at later ages, and continues to be a significant reason for morbidity and mortality. Careful diagnosis and management of HIV-associated kidney disease may minimize the adverse effects of renal disease on the growth and development of these children. In addition, pioneers in kidney transplantation among HIV-infected recipients have made major strides forward, and results have been encouraging. This chapter reviews the spectrum of HIV-related renal disease in children, including approach to diagnosis and management, as well as advances in renal replacement therapies. Drug dosing adjustments for renal impairment of antiretroviral agents and other commonly used medications in HIV infection are also outlined.
The Diets, Preferences, and Overlap of the Primate Community in the Budongo Forest Reserve, Uganda

The forest management in Budongo over the past 60 years has reduced the dominance of C. alexandri and encouraged a more diverse and mixed forest. This has led to a greater density of trees bearing fleshy fruits, particularly C. durandii, which forms an important component of the diet for all the primates. Food availability is probably not the only factor determining primate densities in this forest though, as there is little indication that there is competition for food. It is possible that at the low density sites, food is a determining factor but that at high density sites social factors between primate groups may determine densities rather than food supply. Much of the change in the forest can be attributed to the arboricide treatment rather than the logging because it was not the logging that reduced the monodominance in the forest. In Uganda there has been little hunting of primates for meat because most Ugandans will not eat primate meat. More recently, with movements of people between the Democratic Republic of Congo and Uganda, there are now some people who will hunt primates for meat; however, the level of hunting is still very low in comparison with Central Africa. Care must therefore be taken when extrapolating from these results to other logging sites in Africa. In Central and West Africa, the building of roads by logging companies opens up the forest and encourages hunters to penetrate deeper into the forest. Hunting, rather than the logging practices themselves, exacts a major toll on the wildlife, including primates, in these regions.
The Weighted Sum Rate Maximization in MIMO Interference Networks: The Minimax Lagrangian Duality and Algorithm

We take a new perspective on the weighted sum-rate maximization in multiple-input multiple-output (MIMO) interference networks, by formulating an equivalent max-min problem. This seemingly trivial reformulation has significant implications: the Lagrangian duality of the equivalent max-min problem provides an elegant way to establish the sum-rate duality between an interference network and its reciprocal when such a duality exists, and more importantly, suggests a novel iterative minimax algorithm for the weighted sum-rate maximization. Moreover, the design and convergence proof of the algorithm use only general convex analysis. They apply and extend to any max-min problems with similar structure, and thus provide a general class of algorithms for such optimization problems. This paper presents a promising step and lends hope for establishing a general framework based on the minimax Lagrangian duality for characterizing the weighted sum-rate and developing efficient algorithms for general MIMO interference networks.
An Electron Microscopic Study of Human Epidermis

Since the introduction of the electron microscope there have been a series of improvements in both the microscope and in the technics of preparing the tissue. These have resulted in its present accuracy and widespread use in the biomedical field. The electron microscope has increased resolving power attainable in sections from the previous limit of 2,000 Angstroms with the light microscope to the present limit of 20 Angstroms. In so doing, it has led to a description of many previously unseen structures, and thus to much new terminology in the field of anatomy. Many concepts on structure have had to be revised and many others have been upheld and extended by this new visual aid.
Time and Quantum Measurement

Counting photons as a function of time as they arrive from distant objects is one of the simplest astronomical measurements, and one of the most rewarding. This process is examined in the broad context of scientific measurement in general, in the context of quantum mechanics, along with the contruction of models to match the behavior observed. The relationship between classical and quantum phenomena is placed in a new framework where each is seen to be an essential part of the model building process. Much of the “weirdness” involved in current interpretations of quantum mechanics is thus dispelled, and this new interpretation sheds some light on the nature of time itself.
High-dose intravenous levetiracetam for acute seizure exacerbation in children with intractable epilepsy

SUMMARY We review our experience with high-dose intravenous levetiracetam (IV-LEV) for acute seizure exacerbations in nine children with medically intractable epilepsy. All children had acute repetitive seizures—while on chronic antiepileptic drugs—that either led to hospitalization (eight) or occurred during hospitalization (one), and received doses of IV-LEV of 150 mg/kg/day or greater, with a mean dose of 228 ± 48 mg/kg/day. Eight of nine children had resolution of the acute repetitive seizures. Seizure frequency was reduced to less than baseline in seven children (seizure-free in two, ‡80% % reduction in four, and 50% % reduction in one). Except for one child with increased seizures, IV-LEV was well tolerated in all children without complications.
Engineering cellular trafficking via glycosyltransferase-programmed stereosubstitution

The proximate hurdle for cell trafficking to any anatomic site is the initial attachment of circulating cells to target tissue endothelium with sufficient strength to overcome prevailing forces of blood flow. E-selectin, an endothelial molecule that is inducibly-expressed at all sites of inflammation, is a potent effector of this primary braking process. This molecule is a member of a family of C-type lectins, known as selectins, that bind sialofucosylated glycans displayed on either a protein (i.e., glycoprotein) or lipid (i.e., glycolipid) scaffold. On human cells, the predominant E-selectin ligand is a specialized glycoform of CD44 known as hematopoietic cell E-/L-selectin ligand (HCELL). This review focuses on the biology of HCELL/E-selectin interactions in cell migration, and discusses the utility and applicability of glycosyltransferase-programmed stereosubstitution (GPS) for glycoengineering HCELL expression. Without compromising cell viability or native phenotype, this exoglycosylation technology literally “sweetens” CD44, licensing E–selectin dependent vascular delivery for all cell-based therapeutics.
A quasiclassical trajectory study of the reaction O(3P) + HCl (ν = 2, j = 1, 6, 9) → OH(ν′, j′) + Cl on a new potential surface

A quasiclassical trajectory analysis of the reaction of O(3P) with HCl at a collision energy of 3.2 kcal/mol is presented. The potential surface used is based on ab initio calculations at the MRCl level. The MRCl energies with the Davidson correction (MRCI + Q) were scaled in a manner similar to the scaling external correlation (SEC) method of Brown and Truhlar and fitted to a simple analytic function. This surface has a reaction barrier of approximately 10.06 kcal/mol. The classical dynamics of the reaction are studied by initiating 20000 trajectories in each of the three initial states HCl (ν = 2, j = 1, 6, 9). The results are compared to the experiments of Zare and coworkers.
A comparison of K−p→π−Y1∗+(1385) and π+p→K+Y1∗+(1385) at 5.5 GeV/c

Abstract At 5.5 GeV/ c incident momentum the rate for K − p →π − Y 1 ∗+ (1385) exceeds the rate for π + p → K + Y 1 ∗+ (1385) by a factor of ∼1.8. This factor is qualitatively predicted by a one-meso exchange model when absorption is taken into acocunt.
Corepressors in Mediating Repression by Nuclear Receptors

Publisher Summary Nuclear receptors are modular proteins characterized by a central zinc finger coordinated DNA binding domain, a C-terminal ligand binding domain (LBD), and a variable N-terminal domain. The LBD consists of a number of layered anti-parallel α-helices assembled to form a ligand binding cavity with a protruding C-terminal α-helix (AF-2) that changes position upon ligand binding. In the absence of hormone, corepressors including NCoR and SMRT interact with the receptor LBD through an elongated helix containing variations of the sequence LXXI/HIXXXI/L, also referred to as the CoRNR-box. NCoR and SMRT are huge adaptor proteins that interact with the same NR hydrophobic pocket contacted by alternate coregulatory factors characterized by LXXLL motifs. HDAC3 plays a major role in nuclear receptor corepressor activity for many transcriptional targets. HDAC3 activity is mediated by direct association with NCoR/SMRT through interaction with one of the two highly conserved domains originally identified in SWI3, ADA2 and TFIIIB, termed the SANT domain. HDAC3 can be localized to the inner cytoplasmic membrane and the cytoplasm, in addition to the nucleus. The primary amino acid sequence reveals two nuclear export signals on HDAC3 and a C-terminal nuclear localization signal (NLS). Subcellular localization of HDAC3 has been attributed to a number of posttranslational modifications. During apoptosis, caspase dependent cleavage of HDAC3 separates the C-terminal NLS from the catalytic domain and HDAC3 enzymatic activity is relegated to the cytoplasm and can associate with IкB. Enzymatic activity of HDAC3 can also be regulated by posttranslation modification.
Improving BGP Convergence Time via MRAI Timer

The Border Gateway Protocol (BGP) is the path vector protocol that routes inter-domain traffic, connecting Autonomous Systems (AS’s) together to form the decentralized backbone of the Internet. In the event of a network failure, BGP can take minutes to converge under default settings. With the route withdrawal rate limit (WRATE) change in the new BGP specification, the effect of the Minimum Route Advertisement Interval (MRAI) timer on convergence time needs to be re-evaluated. This paper shows that the reduction of the MRAI timer remains critical to the improvement of BGP convergence time. This paper also shows that while WRATE is not effective in improving convergence time, it reduces the number of transient loops and messages on the network at the optimal MRAI value.
Morphological and property investigations of carboxylated cellulose nanofibers extracted from different biological species

Carboxylated cellulose nanofibers were extracted from different biological species, including cotton, spruce wood, bamboo and bacterial cellulose, through a combined (2,2,6,6-tetramethyl- piperidine-1-yl)oxyl (TEMPO)-mediated oxidation and mechanical defibrillation treatment. The cross-section dimensions of isolated cellulose nanofibers in suspension were characterized by small-angle X-ray scattering, where the results were in agreement with the transmission electron microscopy measurement. For the spruce wood samples, the effects of three experimental variables in the combined TEMPO-oxidation and mechanical treatment on the dimensions and degree of oxidation of the resulting cellulose nanofibers were quantitatively investigated.
Bacterial infection–related glomerulonephritis in adults

In the past, most cases of bacterial infection–related glomerulonephritis (IRGN) occurred in children following streptococcal upper respiratory tract or skin infections and were called postinfectious GN. Over the past 3 decades, there has been an important shift in epidemiology, bacteriology, and outcome of IRGN. A significant percentage of cases now target adults, particularly the elderly or immunocompromised. Because adult infections are often ongoing at the time of diagnosis, the term IRGN appears more appropriate. The sites of infection in adult IRGN are more heterogeneous than in children, and include the upper respiratory tract, skin, lung, heart, urinary tract, teeth/oral mucosa, and bone. In adults, the disease is more likely to be secondary to non-streptococcal infections, particularly staphylococcal infection. In contrast to the favorable course in children, a significant proportion of adults with IRGN, especially the elderly and diabetics, do not recover renal function. Whereas the pathogenesis of post-streptococcal glomerulonephritis has been studied extensively, leading to the identification of two candidate nephritogenic streptococcal antigens, glyceraldehyde-3-phosphate dehydrogenase and pyrogenic exotoxin B, few investigations have focused on IRGN caused by other bacteria. This review will address the current status of sporadic bacterial IRGN in adults.
Measurement of a variable frequency drive loss and efficiency using both calorimeter and powermeter

Variable frequency drive efficiency plays an important role in green energy applications. However, how to accurately measure drive loss and efficiency is still a question to the industry. This paper reviews the powermeter method, calorimeter method, and factors that affect accuracy. After a calorimeter is constructed and calibrated, a variable frequency drive is tested using both methods. Test results are compared and uncertainty analysis is given.
Comparison of argon and CO2 laser stapedotomy in primary otosclerosis surgery

Abstract Purpose: The primary use for the laser in otosclerosis surgery is to create a stapes footplate fenestration that obviates the need for mechanical footplate removal. Experimental studies that evaluate the potential safety of visible (argon and potassium-titanyl-phosphate [KTP]) and invisible (CO 2 ) light laser systems in stapes surgery report conflicting results. The purpose of this study is to compare the clinical safety and efficacy of the CO 2 and argon laser systems when used for primary laser stapedotomy. Materials and Methods: A retrospective case review of 124 primary laser stapedotomies using either the argon (n = 59) or CO 2 (n = 65) laser was performed. Data consisted of pre- and postoperative air and bone conduction audiometry, speech discrimination scores (SDS), intraoperative findings, and postoperative complications. Between group differences (argon v CO 2 ) were sought using standard statistical methodology. Results: The argon and CO 2 laser groups were comparable with regards to age, sex, preoperative air-bone gap, and laterality. Mean preoperative air and bone conduction pure-tone average (PTA) and SDS were somewhat higher in the CO 2 laser group ( P Conclusions: The results suggest that the argon and CO 2 laser systems are comparable with regards to safety and efficacy when used by experienced surgeons for stapedotomy. (Am J Otolaryngol 2000;21:227-230. Copyright © 2000 by W.B. Saunders Company
DOPPLER SCINTILLATION MEASUREMENTS OF THE HELIOSPHERIC CURRENT SHEET AND CORONAL STREAMERS CLOSE TO THE SUN

Prominent enhancements in Doppler scintillation lasting a fraction of a day (solar source several degrees wide) and overlying the neutral line represent the signature of the heliospheric current sheet and the apparent interplanetary manifestation of coronal streamers near the Sun. This first detection of coronal streamers in radio scintillation measurements provides the link between in situ measurements of the spatial wavenumber spectrum of electron density fluctuations beyond 0.3 AU and earlier measurements deduced from radio scintillation and scattering observations inside 0.3 AU. Significant differences between the density spectra of fast streams and slow solar wind associated with the heliospheric current sheet near the Sun reinforce the emerging picture that high-and low-speed flows are organized by the large-scale solar magnetic field, and that while the contrast between solar wind properties of the two flows is highest near the Sun, it undergoes substantial erosion in the ecliptic plane as the solar wind expands.
Heparin preserves nitric oxide activity in coronary endothelium during ischemia-reperfusion injury

Abstract Background . Brief episodes of ischemia followed by reperfusion adversely affect endothelial vasomotor function. We hypothesized that heparin may impart a protective effect on the coronary endothelium during ischemia-reperfusion injury possibly via the nitric oxide pathway. Methods . Eighteen anesthetized dogs were randomly assigned to one of two treatment groups: saline solution or bovine heparin (6.0 mg · kg intravenously). A flow probe and cannula were placed in the left anterior descending artery. Functional recovery of the coronary endothelium was assessed after 15 minutes of ischemia and during 120 minutes of reperfusion after acetylcholine and nitroprusside challenge. In a separate group (n = 10), nitric oxide activity was measured as nitrate/nitrite levels and cyclic guanosine monophosphate levels in the left anterior descending artery. Results . Control dogs displayed a significant decrease in percent change of left anterior descending artery flow at 15, 30, and 60 minutes of reperfusion (67% ± 8%, 76% ± 11%, and 84% ± 8%) when compared with preischemic values (108 ± 6; p p p Conclusions . Heparin preserves the vasoregulatory function of the coronary endothelium during brief episodes of ischemia-reperfusion injury, in part, via the nitric oxide pathway. Administration of heparin may have important therapeutic implications in the prevention of coronary endothelial dysfunction associated with reperfusion injury.
New polyisobutylene-based model elastomeric ionomers: RheoLogical behavior

The rheological behavior of sulfonated polyisobutylene based elastomeric ionomers has been studied. The effects of molecular architecture, type of cation, and addition of excess neutralization agent were investigated. The effect of temperature was studied to a limited extent. In a specific case, the influence of an ionic plasticizer, zinc stearate was also examined. It was found that in these telechelic ionomers where the ionic groups are located exclusively at the chain ends, significant Ionic interactions may persist even at 180°C. The zinc-neutralized ionomers had the lowest viscosity as compared to the corresponding potassium- or calcium-neutralized ionomers. The covalent character of zinc is believed responsible for this behavior. Other factors being constant, the triarm based ionomers are more viscous than the monofunctional ionomers. A mixture of monofunctional ionomers with the triarm, species is a model for dangling chain ends, and results in a slight lowering of the viscosity under the conditions studied. Zinc stearate acts as an ionic plasticizer. Upon the addition of 15 percent by weight of zinc-stearate to the ionomer, the low shear rate viscosity drops by several orders of magnitude and renders the ionomer thermally processable at moderate temperatures.
Role of zebrafish thrombocyte and non-thrombocyte microparticles in hemostasis

Hemostasis is a defense mechanism that protects an organism from bleeding in the event of injury. We have previously demonstrated the utility of the zebrafish as a model to study human hemostasis. However, there are no studies on the role of microparticles in hemostasis in early vertebrates. Studying microparticles in zebrafish may provide insight into the evolution of microparticle function in hemostasis and may lead to direct observation of these microparticles in zebrafish larvae due to transparency of the vessels. In this investigation we demonstrate the presence of cellular microparticles in fish blood by both immunostaining as well as by using zebrafish whose thrombocytes are labeled with green fluorescent protein. Further investigation showed that microparticles were also labeled by fluorescein isothiocyanate annexin V, suggesting that these particles are derived via apoptosis. A portion of the fluorescein isothiocyanate annexin V labeled microparticles was also labeled by DiI-C18. Labeling by DiI-C18 suggests that some microparticles are derived from young thrombocytes. Additionally, GpIIb antibody labels almost all thrombocyte-derived microparticles and a greater percentage of microparticles are labeled by GpIIb antibody than by DiI-C18. This suggests that thrombocyte microparticles are derived from both young and mature thrombocytes. Furthermore, the increase of microparticles by adding excessive microparticles into blood in vitro and through intravenous injections led to an increased hemostatic response. In addition, treatment with tumor necrosis factor alpha resulted in an increased number of thrombocyte microparticles and enhanced hemostasis; in contrast, treatment with zVAD-FMK, a caspase inhibitor, resulted in a decrease in thrombocyte microparticles and decreased hemostasis. We also found that thrombocyte microparticles agglutinate, along with other cells and cellular microparticles, in the presence of an excess of either ristocetin or ultra-large von Willebrand factor. Also, stimulation of von Willebrand factor release in vivo resulted in clusters of thrombocyte microparticles in the veins. Moreover, thrombocyte microparticles were the first to appear at the site of arterial injury. We found that thrombocyte microparticles are functionally equivalent to platelet microparticles. The microparticles initiate arterial thrombus formation in a von Willebrand factor-dependent manner and further enhance thrombus formation by forming clusters of microparticles in venous thrombosis. This finding may have applications for understanding the role of platelet microparticles in humans and may have diagnostic applications.
Invited Article: The Construct of Suspicion and How It Can Benefit Theories and Models in Organizational Science

This article introduces the construct of suspicion to researchers in business and applied psychology, provides a literature-based definition of state suspicion and an initial self-report measure of that construct, and encourages research on this important topic. The construct of suspicion is under-researched in business and applied psychology, yet has wide application for both researchers and practitioners. These applications occur across many content domains (e.g., consumer psychology, leadership), as well as at varying levels of analysis (e.g., individual, group, organizational). To motivate research on this construct, possible studies are delineated/suggested by way of example and a Call for Papers also appears. The organizational sciences will benefit from the incorporation of suspicion-based constructs in theoretical and explanatory models. Organizations might also function more efficiently because of these efforts —as decision makers assess, understand, and better manage appropriate levels of suspicion in their employees and work groups.
Lead isotopes in tree rings: Chronology of pollution in Bayou Trepagnier, Louisiana

We have measured the Pb isotopic composition of tree rings from seven trees in both highly contaminated and relatively noncontaminated regions of Bayou Trepagnier, a bayou in southern Louisiana that has had oil refinery effluent discharged into it over the past 70 years. To our knowledge, this is the first time that Pb isotope tree-ring records have been used to assess the sources and extent of heavy-metal contamination of the environment through time. When tree ring 206Pb/208Pb and 206Pb/207Pb isotope ratios are plotted against one another, a straight line is defined by four of the most contaminated trees. This linear correlation suggests mixing between two sources of Pb. One of the sources is derived from the highly polluted dredge spoils on the banks of the bayou and the other from the natural environment. The nature of the contaminant Pb is unique in that it is, isotopically, relatively homogeneous and extremely radiogenic, similar to ores of the Mississippi Valley (i.e., 206Pb/207Pb = 1.28). This sin...
Historical Understanding and the Human Sciences

Historical Understanding and the Human Sciences By Mark Bevir I. CONTACT INFORMATION Department of Political Science, University of California, Berkeley, CA 94720, USA Email: mbevir@berkeley.edu II. BIOGRAPHICAL NOTE Mark Bevir is a Professor in the Department of Political Science, University of California, Berkeley. He is the author of The Logic of the History of Ideas (1999) and New Labour: A Critique (2005), and co-author, with R. A. W. Rhodes, of Interpreting British Governance (2003) and Governance Stories (2006).
Monitoring Cardiac Troponin Structural Changes using In-Situ Time-Resolved FRET: Implications on the Regulatory Roles of Cross-Bridges and Sarcomere Length

During cardiac thin filament activation, the N-domain of Ca2+-binding cardiac troponin C (N-cTnC) interacts with the actomyosin inhibitory troponin I (cTnI) subunit, which concomitantly opens the cTnC N-domain and leads to force generation. Recently, we used in situ steady state FRET measurements based on N-cTnC opening to determine that strongly bound cross-bridges (XBs) stabilize this Ca2+-sensitizing N-cTnC-cTnI interaction. However, the method was unable to determine how N-cTnC opening is affected by sarcomere length (SL). In this study, we used time-resolved in situ FRET to monitor the effects of Ca2+-occupancy, XB state, and SL on N-cTnC opening in skinned cardiac muscle fibers. FRET donor (AEDANS) and acceptor (DDPM) modified double-cysteine mutant cTnC(13C/51C)AEDANS-DDPM was reconstituted into skinned muscle fibers to examine the N domain of cTnC (N-cTnC) opening. To study the effect of SL on structural transitions of cTnC, we monitored the protein structural transitions at low and high [Ca2+] and SL 1.8 and 2.2 μm. Mg2+-ADP and sodium orthovanadate (Vi) were used to examine the effects of non-cyclng strong and weak XBs, respectively. We found that strongly bound XBs alter structural transitions of cardiac troponin only at 2.2 μm. On the other hand, Vi blunted the SL dependent opening of N-cTnC such that weak XBs have no effect on N-cTnC at either [Ca2+] or SL. In addition, distance distribution analysis indicated that N-cTnC adopts four unique conformations associated with the four states of thin filament regulation, and that N-cTnC conformational equilibria are caused by cycling XBs. Based on our findings, we conclude that the observed dependence of myosin positive feedback regulation on SL is an important determinant of the Frank-Starling law of the heart.
Biosynthesis of the coumarins. Tracer studies on coumarin formation in Hierochloe odorata and Melilotus officinalis.

Coumarin formation has been studied with C14 in the perennial grass, Hierochloe odorata, and in yellow sweet clover, Melilotus officinalis. In general the latter species yielded inconsistent data. ...
Assessing the reliability of wall-coated microfabricated gas chromatographic separation columns

Abstract This study addresses several aspects of etched-silicon/glass microfabricated channels that affect their performance as micro-gas chromatographic (μGC) separation columns, including the consistency of stationary phase deposition, deactivation of surface-adsorption sites on the microcolumn walls, and the stability of the stationary phase following repeated thermal cycling. Convolved square-spiral microcolumns 0.5–3-m long with cross sections of 150 μm × 240 μm consisting of deep-reactive-ion-etched (DRIE) Si with anodically bonded Pyrex caps are used. Replicate devices with wall-coated films of the non-polar polydimethylsiloxane (PDMS) or the moderately polar poly(trifluoropropylmethyl)siloxane (PTFPMS) deposited statically to a nominal thickness of 0.15 μm provide minimum plate heights that are reproducible to 5% in air or helium carrier gases. Using split-flow injection, 4900 theoretical plates/m can be produced and a 19-vapor mixture can be separated on a 0.5-m PDMS-coated column in air in less than 3.5 min. Significant reductions in peak tailing of polar analytes are afforded by surface pre-treatment or post-treatment with the deactivation agent hexamethyldisilazane (HMDS). In addition, retention times remain stable and peak widths remain stable or decrease after prolonged pre-conditioning at 200 °C in air. Non-pretreated PTFPMS-coated microcolumns can produce 2300 plates/m and also retain high resolution after pre-conditioning at 200 °C in air. Marginal improvements in separation efficiency are achieved by pre-treatment with trifluoropropylmethylcyclotrisiloxane. Results demonstrate that efficient μGC columns with polar and non-polar stationary phases can be made reproducibly and operated at elevated temperatures in air.
Activation energy calculations for discontinuous yielding in Inconel 718SPF

Abstract The kinetics of yield point return and of dynamic strain aging (DSA) were investigated for a commercial heat of Inconel 718SPF. During uniaxial tensile tests, the alloy exhibited serrated flow on the load–elongation curves at intermediate temperatures. Types A, B and C serrations were observed depending upon the test temperature and strain rate. For type A and B serrations, apparent activation energies ranging from 97 to 133 kJ mol −1 were measured, which suggests that type A and B serrated flow results from the diffusion of an interstitial solute, most likely carbon. For type C serrations, apparent activation energies in the range ∼210 to ∼272 kJ mol −1 were measured, which suggests that type C serrations arise from the diffusion of a substitutional solute, most likely Cr. Yield points induced during strain aging under stress experiments increased with a t n relationship, where the exponent n ranged from 0.3 to 0.5 before reaching a plateau. This suggests that the yield points were a combined result of bulk lattice diffusion and dislocation pipe diffusion of solutes. The apparent activation energies, ranging from 42 to 50 kJ mol −1 , are consistent with prior observations, but cannot be explained by any classic models for static strain aging. It is suggested that the yield points result from the reorientation of carbon-vacancy pairs in the strain fields of dislocations.
Near-Threshold Fatigue Crack Growth in 2 1/4 Cr-1Mo Pressure Vessel Steel in Air and Hydrogen

As part of an ongoing program to examine subcritical flaw growth in candidate steels for proposed coal gasifier pressure vessels, an initial study is made of characteristics of ultralow growth rate fatigue crack propagation in thick-section, normalized 2 1/4 Cr-1Mo pressure vessel steel (ASTM A387, Class 2 Grade 22). Crack propagation data are generated over a wide range of growth rates, from 10−8 to 10−2 mm/cycle, for load ratios between 0.05 and 0.80 at ambient temperatures in low pressure environments of moist air, dry hydrogen gas and dry argon gas. Particular emphasis is placed on behavior at near-threshold growth rates, below 10−6 mm/cycle, approaching the so-called threshold stress intensity for fatigue crack growth, ΔK0 . Near-threshold growth rates, in addition to showing a marked sensitivity to load ratio, are found to be significantly enhanced in gaseous hydrogen compared to air. Similar environmentally-enhanced growth is observed in argon gas. To account for such results, previous models of threshold behavior based on environmental factors (e.g., hydrogen embrittlement) are questioned, and a new approach is presented in terms of the role of oxide debris from moist environments in promoting crack closure. This oxide-induced closure model is found to be consistent with most experimental observations of near-threshold fatigue crack propagation behavior and is proposed as a mechanism for environmental effects at ultra-low growth rates.
The effect of recombinant bovine placental lactogen on induced lactation in dairy heifers

The primary objective of this study was to determine whether bovine placental lactogen stimulated additional mammary growth as assessed by milk yield from a lactation induced by steroids. Pubertal, nonpregnant Holstein heifers (n = 23) were given daily subcutaneous injections of estradiol-17β (0.05 mg/kg) and progesterone (0.25 mg/kg) for 7 d to initiate mammary growth. Prolactin secretion was suppressed in all heifers via bromocriptine, which was administered until d 15. Heifers were treated with either placental lactogen (40 mg/d; n = 12) or water (control group; n = 11) for 18 d. Lactation was induced by daily injection of dexamethasone for 3 d and twice daily injections of recombinant bovine prolactin for 5 d starting on d 18. From 3 to 8 wk of lactation, milk yield of heifers treated with placental lactogen was numerically higher (22%) than the yield of control heifers, but the difference was not significant because of the high coefficient of variation. Daily injection of bovine somatotropin (d 57 to 66 of lactation) increased milk yield of both groups and stimulated a greater numerical increase in milk yield for heifers that were treated with placental lactogen. These results support the hypothesis that bovine placental lactogen is mammogenic and is one of the factors that regulates mammary growth during pregnancy.
Employing mutants to study thrombin residues responsible for factor XIII activation peptide recognition: a kinetic study.

In the last stages of coagulation, thrombin helps to activate Factor XIII. The resultant transglutaminase introduces covalent cross-links into fibrin thus promoting clot stability. To better understand the roles of individual thrombin residues in recognition and hydrolysis of the Factor XIII activation peptide, mutations within thrombin's aryl and apolar binding site were explored. The thrombin mutants W215A, E217A, W215A/E217A, L99A, and I174A were examined through HPLC kinetics against the substrates FXIII (28-41) V34 AP and FXIII (28-41) V34L AP. Several mutants responded differently to FXIII (28-41) V34 AP vs the cardioprotective V34L AP. W215 provides an important platform for binding and directing FXIII APs for proper hydrolysis. Loss of this platform leads to decreases in kinetics, particularly to the k cat of FXIII V34L AP. E217 also plays a supporting role, but the E217A mutation is not as detrimental as W215A. W215A/E217A is unfavorable for both activation peptides and its coupling effect has been characterized. This mutant can readily bind the peptides but cannot orient them for effective hydrolysis. Kinetic studies with I174A indicate that this thrombin residue is more crucial for interactions with the larger V34L AP segment. The L99A mutation causes deleterious effects to binding and hydrolysis of both APs. The V34L, however, is able to partially compensate for the loss perhaps by increasing contact within the aryl and apolar sites. Understanding how specific FXIII and thrombin residues participate in binding and control hydrolysis may lead to the design of coagulation enzymes whose degree of activation and optimal target site can be controlled.
Host defense against Neisseria meningitidis requires a complement-dependent bactericidal activity

Some individuals, with severe or recurrent infection with Neisseria species, have been identified as lacking a component in the terminal attack sequence of complement (complement components 5 to 9). The relevance of the terminal attack sequence to various phases of host defense was tested with the use of the C-11 strain of meningococci and human serum genetically deficient in complement component 8 (C8-D). The C8-D serum was comparable to normal serum in supporting ingestion and intracellular killing by leukocytes but was not bactericidal in the fluid phase unless reconstituted with C8. Thus, serum complement-dependent bactericidal activity may be especially critical for the host's defense against invasive Neisseria species.