cssi/SciSciGPT-SciSciNet huggingface dataset:
Compositional and structural insights into the nature of the H-cluster precursor on HydF

Assembly of an active [FeFe]-hydrogenase requires dedicated maturation enzymes that generate the active-site H-cluster: the radical SAM enzymes HydE and HydG synthesize the unusual non-protein ligands – carbon monoxide, cyanide, and dithiomethylamine – while the GTPase HydF serves as a scaffold for assembly of the 2Fe subcluster containing these ligands. In the current study, enzymatically cluster-loaded HydF ([2Fe]F) is produced by co-expression with HydE and HydG in an Escherichia coli host followed by isolation and examination by FTIR and EPR spectroscopy. FTIR reveals the presence of well-defined terminal CO and CN− ligands; however, unlike in the [FeFe]-hydrogenase, no bridging CO is observed. Exposure of this loaded HydF to exogenous CO or H2 produces no significant changes to the FTIR spectrum, indicating that, unlike in the [FeFe]-hydrogenase, the 2Fe cluster in loaded HydF is coordinatively saturated and relatively unreactive. EPR spectroscopy reveals the presence of both [4Fe–4S] and [2Fe–2S] clusters on this loaded HydF, but provides no direct evidence for these being linked to the [2Fe]F. Using the chemical reactivity and FTIR data, a large collection of computational models were evaluated. Their scaled quantum chemical vibrational spectra allowed us to score various [2Fe]F structures in terms of their ability to reproduce the diatomic stretching frequencies observed in the FTIR experimental spectra. Collectively, the results provide new insights that support the presence of a diamagnetic, but spin-polarized FeI–FeI oxidation state for the [2Fe]F precursor cluster that is coordinated by 4 CO and 2 CN− ligands, and bridged to an adjacent iron–sulfur cluster through one of the CN− ligands.
Stress Induced Mutagenesis, Genetic Diversification, and Cell Survival via Anastasis, the Reversal of Late Stage Apoptosis

Changes in genomic DNA are critical for evolution as they generate genetic diversity, which is the substrate for natural selection. However, most mutations are deleterious, so protective mechanisms have evolved such as apoptotic cell death, to eliminate damaged cells. Apoptosis is generally assumed to be irreversible once massive destruction of structural and functional cellular components occurs. Recent surprising studies reveal that dying cells can reverse the apoptotic process, survive, and proliferate, even after sustaining DNA damage. This process has been named anastasis. While most cells repair their damaged DNA, residual genetic alterations persist in some cells and can result in oncogenic transformation. Although proliferation of transformed cells is a negative consequence, anastasis may serve useful purposes as well. For example, such a cell survival mechanism could serve to salvage postmitotic cells, which are difficult to replace, and thereby limit permanent tissue damage due to transient stresses. The DNA mutations that persist following anastasis represent a form of stress-induced mutagenesis, increasing genetic and phenotypic diversity in response to environmental or physiological stresses that initiate apoptosis. Negative side effects of this otherwise beneficial process may include carcinogenesis and evolution of drug resistance following chemotherapy.
Calibration of Lutetium for Measurements of Effective Neutron Temperatures

Experiments were conducted to determine the feasibility of using the ratio of activity of Lu/sup 177/ to that of Lu/sup 176m/ to measure effective neutron temperature. The experimental results include the half life of each activity, cadmium ratios for each isotope, and the ratio of the two activities for various neutron temperatures. The half lives were measured as 6.74 plus or minus 0.04 days and 3.69 plus or minus 0.04 hr for Lu/sup 177/ and Lu/sup 176m/ , respectively. (W.L.H.)
Ablation Outcomes for HIV-Infected and Uninfected Patients with Anal High-grade Squamous Intraepithelial Lesions (HSIL)

Background HPV-induced anal HSIL, the putative anal cancer precursors, are highly prevalent in HIV-infected patients. Screening and ablation of anal HSIL has been proposed for high-risk patients but is associated with substantial recurrence rates. Using data from a large anal cancer-screening cohort, we evaluated long-term outcomes following HSIL ablation. Methods 427 participants with HSIL were treated with electrocautery ablation. Using HRA, surveillance was conducted within 12 months to assess treatment response. HSILs in the same anatomic region as the index lesion were defined as persistent; HSILs in a different region were defined as metachronous. Results Our cohort consisted of MSM (93%) and HIV+ persons (91%). HSIL persistence after ablation was 39% (95% CI: 34%-43%) and did not differ significantly by HIV status or sexual behavior. Metachronous HSIL was found in 27% (95% CI: 23%-31%). The overall recurrence (persistent plus metachronous) was 53% and was more frequent in HIV+ persons (56% vs. 28%; p=0.001). Subjects with more than one HSIL at baseline had a higher risk of persistence than those with solitary lesions (48% vs. 32%; p=0.001). No other factors were associated with persistence, including age, race/ethnicity, smoking, HIV viral load and CD4 count. After adjustment for baseline number of lesions, HIV infection was associated with overall recurrence of HSIL (odds ratio 3.2; 95% CI: 1.5–6.9). Conclusions In our cohort, over one third of anal HSILs persisted after ablation. HIV+ patients with multiple HSILs at baseline are at a higher risk of recurrence and may require careful surveillance.
The impact of electrical injuries on long-term outcomes: A Burn Model System National Database study

Abstract Introduction Electrical injuries exhibit significant acute and long-term sequelae. Amputation and neurological deficits are common in electrical injury survivors. There is a paucity of information on the long-term outcomes of this population. Therefore, this study examines the long-term outcomes of electrical injuries by comparing them to fire/flame injuries. Methods Data from the Burn Model System National Database collected between 1996 and 2015 was examined. Demographic and clinical characteristics for adult burn survivors with electrical and fire/flame injuries were compared. Satisfaction With Life Scale (SWLS), Short Form-12 Physical Composite Score (SF-12 PCS), Short Form-12 Mental Composite Score (SF-12 MCS), and employment status were examined at 24 months post-injury. Linear and logistic regression models were used to assess differences in outcome measures between groups, controlling for demographic and clinical variables. Results A total of 1147 adult burn survivors (111 with electrical injuries; 1036 with fire/flame injuries) were included in this study. Persons with electrical injuries were more likely to be male and injured at work (p Conclusions Adult survivors with electrical injuries reported worse physical health and were less likely to be employed at 24 months post-injury compared to survivors with fire/flame injuries. A more detailed understanding of return to work barriers and work accommodations is merited for the electrical injury population. Furthermore, the results of this study should inform future resource allocation for the physical health and employment needs of this population.
The Intersections Between Social Determinants of Health, Health Literacy, and Health Disparities

This chapter synthesizes what is known about the relationship between social disadvantage and measures of low health literacy (LHL), and reviews the research examining whether LHL is an explanatory factor connecting social disadvantage, health outcomes, and health disparities. Written from a U.S. perspective, the chapter then offers a novel conceptual framework that presents how the social determinants of health might interact with LHL to result in health disparities. The framework articulates relationships that reflect public health pathways and healthcare pathways, which include their related health literacies. In addition, the chapter highlights as an exemplar one important potential causal mechanism in the healthcare pathway by exploring the communication model in outpatient care, as communication has been very well-studied with respect to both health disparities and HL. The chapter then, provides two examples of HL interventions aligned with the conceptual framework, one of which addresses the health care literacy pathway, and the other addresses the public health literacy pathway. The chapter continues with a number of cautionary statements based on the inherent limitations of current HL research, including problems and concerns specific to the attribution of HL as an explanatory factor for extant socioeconomic and racial/ethnic health disparities. The chapter closes with recommendations regarding future research directions.
GLAD: GLocalized Anomaly Detection via Human-in-the-Loop Learning

Human analysts that use anomaly detection systems in practice want to retain the use of simple and explainable global anomaly detectors. In this paper, we propose a novel human-in-the-loop learning algorithm called GLAD (GLocalized Anomaly Detection) that supports global anomaly detectors. GLAD automatically learns their local relevance to specific data instances using label feedback from human analysts. The key idea is to place a uniform prior on the relevance of each member of the anomaly detection ensemble over the input feature space via a neural network trained on unlabeled instances. Subsequently, weights of the neural network are tuned to adjust the local relevance of each ensemble member using all labeled instances. GLAD also provides explanations which can improve the understanding of end-users about anomalies. Our experiments on synthetic and real-world data show the effectiveness of GLAD in learning the local relevance of ensemble members and discovering anomalies via label feedback.
eDNA metabarcoding as a biomonitoring tool for marine protected areas

Abstract Monitoring of marine protected areas (MPAs) is critical for marine ecosystem management, yet current protocols rely on SCUBA-based visual surveys that are costly and time consuming, limiting their scope and effectiveness. Environmental DNA (eDNA) metabarcoding is a promising alternative for marine ecosystem monitoring, but more direct comparisons to visual surveys are needed to understand the strengths and limitations of each approach. This study compares fish communities inside and outside the Scorpion State Marine Reserve off Santa Cruz Island, CA using eDNA metabarcoding and underwater visual census surveys. Results from eDNA captured 76% (19/25) of fish species and 95% (19/20) of fish genera observed during pairwise underwater visual census. Species missed by eDNA were due to the inability of MiFish 12S barcodes to differentiate species of rockfishes (Sebastes, n=4) or low site occupancy rates of crevice-dwelling Lythrypnus gobies. However, eDNA detected an additional 30 fish species not recorded in paired visual surveys, but previously reported from prior visual surveys, highlighting the sensitivity of eDNA. Significant variation in eDNA signatures by location (50m) and site (~1000m) demonstrates the sensitivity of eDNA to address key questions such as community composition inside and outside MPAs. Interestingly, eDNA results recorded higher species richness outside the MPA while visual surveys observed the opposite pattern. This result is likely caused by swamping effects of high fish abundance in MPAs that reduce detection probabilities of pelagic and intertidal taxa. Results demonstrate the utility of eDNA metabarcoding for monitoring marine ecosystems, providing an important complementary tool to visual methods.
Laissez-faire Ableism in the Academy: Contouring the Map with Graduate Student Perspectives

Graduate studies present unique contexts for accommodation due to the factors such as student age, professional background, and employment status within the university. Scholars recognize the need to reframe the dominant narrative which positions dis/ability in relation to ability, or ableism. The present study uses graduate student experiences with self-advocacy to examine Laissez-faire ableism at interactional and personal levels of higher education. We argue that dis/ability accommodation should be viewed as an iterative and interactive process between the student, faculty, and other institutional actors such as Dis/ability Services. The authors are doctoral students in education with hidden dis/abilities who are racialized differently. This article values dis/abled student voice as essential to the equity and inclusion for dis/abled students (Pearson, 2015). We use Black Feminism in Qualitative Inquiry (BFQI) and duoethnography to empirically investigate our ongoing attempt to transform our institutional climate. Our purpose is to highlight the centrality of humanity in the pursuit of dis/ability justice by putting our lived experiences becoming coconspirators in conversation with each other.
Learning More About HHV-6 Encephalitis

In this issue of Neurology® Neuroimmunology & Neuroinflammation , a retrospective study using an institutional virology database addresses the clinical nature, radiologic findings, and biological underpinnings of human herpesvirus 6 (HHV-6) encephalitis. The data had been …
Identifying Agricultural Managed Aquifer Recharge Locations to Benefit Drinking Water Supply in Rural Communities

Author(s): Marwaha, N; Kourakos, G; Levintal, E; Dahlke, HE | Abstract: The southern Central Valley of California is one of the most productive agricultural regions in the world. Yet, decades of groundwater use beyond sustainable yield have left rural communities highly vulnerable to shortages and contamination of their drinking water supply. As state regulation begins to address these issues, a need exists to design adaptive and appropriate management systems to increase resilience of rural communities. Targeted managed aquifer recharge on agricultural land (Ag-MAR) near rural communities is one such strategy that could potentially stabilize groundwater tables and maintain or improve groundwater quality in domestic supply wells. Here we present a geographic information system-based multicriteria decision analysis that combines biophysical data (soils, land use, and surface water conveyance) with groundwater modeling and particle tracking to identify suitable agricultural land parcels for multibenefit groundwater recharge within well capture zones of 288 rural communities. Parcels are prioritized using a vulnerability index to change in groundwater supply, derived from well reliance and failures, pesticide applications, land subsidence, and socio-economic data. Our analysis identifies 2,998 suitable land parcels for Ag-MAR within the well capture zones of 149 of the 288 communities, of which 144 rely mainly on groundwater for drinking water. The majority of identified Ag-MAR parcels serve communities ranked as having extreme or very high vulnerability to changes in groundwater supply. Our research produces new understanding of factors contributing to community vulnerability and resilience to changes in drinking water supply and can be used to discuss actions to help achieve a stable and high-quality water supply.
Hydrosurgical Debridement Use Associated With Decreased Surgical Site-Related Readmissions: A Retrospective Analysis.

INTRODUCTION Debridement is the cornerstone of wound care management. It allows for the removal of fibrinous and necrotic debris from the wound bed as well as the reduction of bacterial bioburden, thus allowing for proper granulation and wound healing. Hydrosurgical debridement uses a controlled, high-pressure fluid jet to cut and remove necrotic debris, contaminants, and bacteria, thereby facilitating a potentially more aggressive debridement. OBJECTIVE The efficacy of this system was compared with that of other methods of debridement in reducing readmissions due to surgical site infections (SSIs). MATERIALS AND METHODS Two Current Procedural Terminology codes were used to identify 289 unique patients treated for lower extremity wounds. All patients were treated at a vascular surgery service in a large tertiary care wound program from January 2016 to June 2018. Chart review on wound management was performed. A total of 190 of the 289 patients underwent wound debridement over the course of treatment. Logistic regression was calculated with subsequent SSI admission as the dependent variable. RESULTS On assessing readmissions owing to SSI following debridement, use of hydrosurgical debridement was found to be associated with decreased SSI admissions (odds ratio, 0.31; 95% CI, 0.142-0.677; P < .05). This finding was compared with the results of either standard sharp soft tissue excisional debridement or the use of pulse irrigation. CONCLUSIONS There are multiple options to consider when formulating an approach for wound management, including the method of debridement used. One goal of debridement is to decrease the bacterial bioburden in the wound bed to both encourage better wound healing and decrease the rate of wound infections. The present study found that the use of hydrosurgical debridement was associated with decreased SSI readmissions, which could potentially result in better wound care for the patient and possibly decreased health care costs because of a lower rate of readmissions. Further investigation of these 2 potential outcomes is necessary.
Does Private Equity Over-Lever Portfolio Companies?

Detractors have warned that Private Equity (PE) funds tend to over-lever their portfolio companies because of an option-like payoff, building up debt overhang and widespread bankruptcy risks. Drawing on standard trade-off theory, this paper argues PE-ownership leads to higher levels of optimal (value-maximizing) leverage. I embed key features of PE-ownership into a model of firm value, leverage and credit risk. Using a large sample of PE-sponsored leveraged buyouts (LBO), the estimated model fully explains both the level and change in leverage ratios in the data following PE-takeover. Higher levels of optimal leverage arise endogenously from (i) lower asset volatility (ii) higher expected future return and (iii) lower deadweight bankruptcy costs. In equilibrium, tax benefit is greater and expected distress cost of debt is much lower since bankruptcy is both less likely and less costly. Counterfactual analysis reveals substantial loss in firm value if PE sub-optimally chose lower leverage. Post-LBO, I estimate Distance-to-Default increases by 28 percent and credit spreads narrow by 3.6 percentage points for the median firm, suggesting concerns about default risks may have been overstated. Additional tests show PE-backed firms receive equity injections from sponsoring funds if they fall into financial distress, corroborating the lower distress cost channel. My results suggest new policies regulating leveraged loans should focus on the borrower's optimal capital structure.
Model Verification and Validation

Model Verification and Validation (V&V) is concerned with having a model and the model’s results “correct” for a specific model use or purpose. This chapter presents an overview of V&V of computerized structural models. Formally, model verification of computerized structured models is defined as “ensuring that the computer program of the computerized model with its solution method and the computer program’s implementation are correct” and model validation is defined as the “substantiation that a computerized model within its domain of applicability possesses a satisfactory range of accuracy consistent with the intended application of the model.” Model V&V is part of the model development process. The overview of V&V presented includes the decision-making approaches for deciding model V&V, a graphical paradigm for relating V&V to the model development process, a discussion of each of the steps of performing V&V during the model development process, the criticalness of documenting V&V, and a recommended model V&V procedure.
The influenza data summary: a prototype application for visualizing national influenza activity

The Influenza Data Summary (IDS) is a tool that provides a unified view of influenza activity in the United States. It currently incorporates data from portions of the U.S. Influenza Surveillance System and BioSense. The IDS allows users to customize dashboards, interactive maps, and graphs from each of these data sources. The purpose of this paper is to provide an overview of the IDS and to discuss current features and future plans for improvement.
Early detection of requirements specification errors

An important class of system errors is defined and initial results with two prototype requirements-analysis tools are described. A requirements-specification technique that is highly operational is presented; it expresses the sequential behavior of a system in terms of processes that are equivalent to Petri nets. Subsequent definitions based on directed graphs describe the possible ways in which individual processes might interact, thereby providing a basis for requirements-analysis tools that can detect class two errors at the end of the requirements-specification phase, rather than after system delivery. >
Tax Policy Inside the Two Kingdoms

This article illustrates that my article, An Evaluation of Federal Tax Policy Based on Judeo-Christian Ethics, which states that tax policy consistent with the moral principles of Judeo-Christian ethics must raise an adequate level of revenues embracing the reasonable opportunity of all individuals to reach their potential under a moderately progressive model is consistent with Gregory Boyd’s interpretation of Two Kingdom Theory in his book The Myth of a Christian Nation. Boyd’s heavy criticism of Christians using Scripture to specifically answer questions and then voting to enforce those values on persons outside the church poses no conflicts with my arguments to persons inside the church. This article concludes that the moral obligation of Christians, especially those enjoying higher levels of income and wealth, to embrace the higher sacrifice required by the general moral guidelines of reasonable opportunity and moderate progressivity and to avoid being tempted to support flat models is consistent with the general themes of Boyd’s book. Although Boyd does not address tax policy he states that costly self-sacrifice must be at the center of kingdom of God responses to ambiguous kingdom of the world issues. Flat tax models not only demand far lower sacrifice from the wealthy as compared to the middle class but are also supported by objectivist ethics, a form of atheism with core values denying the existence of broad duties of self-sacrifice under any circumstances.
Fair Warning to Law Schools... and an Invitation to 1Ls, 2Ls & 3Ls

Aspiring law students and professors should have more and better information about the relative quality of law schools. Unfortunately, the people in the best positions to provide that information - the AALS and ABA - have powerful reasons to avoid doing so. The void has been filled in part by the U.S. News rankings. We could go on about their defects and limitations, but we have done that before. U.S. News could improve its product, but why bother? Doing more and better work would be costly, and in the absence of a genuine competitive threat there is no reason to make the investment. Enter the Deadwood Report, in which the Green Bag will provide rough and admittedly partial but transparent measures of law school faculty quality by measuring teaching, scholarship, and (eventually) service. Law schools generally hold themselves out as institutions led by faculties whose members are committed to working in all three areas. Why? Because - according to the law schools and many leaders of the profession - the best teachers tend to be active scholars, and the best scholars tend to be active teachers, and all the best lawyers of every stripe engage in service for the public good. Evidence of the law schools' commitment to this view is reflected in the practically universal requirement of high achievement in all three areas for tenure. And so we should be able to say with some confidence that a good law school will have a faculty consisting of hard-working teacher-scholar-humanitarians. The Deadwood Report will simply test the accuracy of that picture. Our focus will be on the most dully objective of measures: whether the work is being done - whether each law school faculty member is teaching courses, publishing scholarly works, and performing pro bono service.
Degos' disease mimicking vasculitis.

Introduction Degos’ disease is a rare disorder with multisystem involvement and unknown etiology. This entity was first described by Degos in 1942 (1,2). Other synonyms for this disease are malignant atrophic papulosis, atrophic papulosquamous dermatitis, fatal cutaneous-intestinal syndrome, and thromboangiitis cutaneointestinalis disseminata (3). It has been more commonly reported in whites, men, and those in the third decade of life, although onset age ranges from 3 weeks to 67 years (4). The average course of the disease is reported to be around 2 years (1), but case reports of patients with a benign variant have been reported with survival of 14 years (5). Death is most commonly due to intestinal perforation or cerebral infarction. We report a fatal case of Degos’ disease that presented with abdominal pain and intestinal perforations, which clinically mimicked vasculitis.
Notes on the Use of Regional Science Methods in Economic History

My notes this morning are a continuation of Professor Broude's paper which has been circulated. I take the position that study of regional, interregional, and spatial interaction can provide insights for understanding not only national but all economic development. Put even more strongly, a well-balanced economic history must explicitly consider spatial processes and the evolving web of interregional relationships.
A Phase I Study of the combination of oxaliplatin/docetaxel and vandetanib for the treatment of advanced gastroesophageal cancer

Introduction This study aimed to assess the safety and tolerability of the multitargeted tyrosine kinase inhibitor, vandetanib (V), in combination with two chemotherapeutic agents, oxaliplatin (O) and docetaxel (D) in advanced gastroesophageal (GE) cancer. Methods This was a Phase I study (NCT00732745) with a standard 3 + 3 dose escalation design. The primary aim was to determine the optimal dose of the combination of vandetanib and OD chemotherapy. Results Initial treatment for the first cohort consisted of oxaliplatin at 100 mg/m2 on day 1, docetaxel at 35 mg/m2 on days 1 and 8 and vandetanib 100 mg PO daily of 21-day treatment cycles. As dose limiting toxicity (DLT) was reached in 2 out of 3 patients in cohort 1 (one grade 3 and one grade 4 diarrhea with dehydration), 6 patients were treated then at dose level −1 (O 80 mg/m2 on day 1, D 30 mg/m2 on days 1 and 8, V 100 mg PO daily days 1–21) in which no further DLTs were observed. This dose was established as maximum tolerated dose and is the recommended phase 2 dose. 8 out of 9 enrolled patients had adenocarcinoma. At dose level 1, 1 of the 3 patients had a documented partial response and 2 patients had stable disease. At dose level −1, 1 of 6 patients achieved a complete response, 2 of 6 patients had stable disease, and 3 of 6 patients had progressive disease. Conclusions Vandetanib added to oxaliplatin and docetaxel showed manageable toxicity and limited activity in advanced GE cancer.
The Inheritance of Two Standard Disqualifications in White Leghorn Chickens

Abstract In outlining the standard requirements for the various breeds and varieties of poultry in the American Standard of Perfection but little consideration has been given to the genetics involved. It is true that very little study has been made of the genetics of such characers as are listed as breed defects and very little reliable information has been available. The fact that a defect has been sufficiently persistent in the breed to be listed as a disqualification may be taken as an indication of its heritability. It is also to be expected that such defects will be of a recessive nature since dominants would not persist in spite of continuous selection against them. It might seem that undesired recessives would also be eliminated by conscious selection against them for a period of any length. However, the writer’s experience with more rapidly breeding forms such as the vinegar fly, Drosophila, has . . .
SLOW INTRACELLULAR ACCUMULATION OF GABAA RECEPTOR δ SUBUNIT IS MODULATED BY BRAIN-DERIVED NEUROTROPHIC FACTOR

Abstract GABAA receptors composed of the γ2 and δ subunits have distinct properties, functions and subcellular localization, and pathological conditions differentially modulate their surface expression. Recent studies demonstrate that acute seizure activity accelerated trafficking of the γ2 and β2/3 subunits but not that of the δ subunit. The trafficking of the γ2 and β2/3 subunits is relatively well understood but that of the δ subunit has not been studied. We compared intracellular accumulation of the δ and γ2 subunits in cultured hippocampal neurons using an antibody feeding technique. Intracellular accumulation of the δ subunit peaked between 3 and 6 h, whereas, maximum internalization of the γ2 subunit took 30 min. In the organotypic hippocampal slice cultures internalization of the δ subunit studied using a biotinylation assay revealed highest accumulation between 3 and 5 h and that of the γ2 subunit between 15 and 45 min. The surface half-life of the δ subunit was 171 min in cultured hippocampal neurons and 102 min in the organotypic hippocampal slice cultures. In the subsequent studies, internalization of the δ subunit was found to be dependent on network activity but independent of ligand-binding. Brain-derived neurotrophic factor (BDNF) reduced buildup of the δ subunit in the cytoplasmic compartments and increased its surface expression, and this BDNF effect was independent of network activity. BDNF effect was mediated by activation of TrkB receptors, PLCγ and PKC. Increase in the basal PKC activity augmented cell surface stability of the δ subunit. These results suggest that rate of intracellular accumulation of the δ subunit was distinct and modulated by BDNF.
NMR AT CRYOGENIC TEMPERATURES : A 13C NMR STUDY OF FERROCENE

A new cryogenic apparatus is described that can be used to obtain NMR spectra at temperatures down to 8−10 K. The static solid 13C NMR spectrum of ferrocene is recorded at that temperature. Spectra recorded at higher temperatures show that ferrocene is still freely rotating about its 5-fold symmetry axis on the 13C NMR time scale at 45−50 K. A comparison of the principal values of the 13C chemical-shift tensor obtained from the room- and low-temperature spectra of ferrocene indicates that the lowest frequency chemical shift principal component, δ33, is tilted off this symmetry axis by approximately 12°. Quantum chemical calculations of the chemical-shift tensor, completed on structures of ferrocene from the literature as well as on optimized structures with the cyclopentadienyl rings locked in both the staggered and eclipsed arrangements, predict the angle between the δ33 direction and the rotation axis to be between 11° and 15°, depending upon the geometry used in the calculation. The calculations also p...
Activation of PKC-Alpha Increases Ca2+ Sparklet Activity in Cardiac Myocytes

Ca2+ sparklets are local elevations in intracellular Ca2+ produced by the opening of a single or a small cluster of sarcolemmal L-type Cav1.2 Ca2+ channels. At present, however, the spatial organization and mechanisms of modulation of Ca2+ sparklets in cardiac myocytes is unknown. Here, we tested the hypothesis that Ca2+ sparklets activity varies within the sarcolemma of neonatal cardiac myocytes and that chemically-induced translocation of PKCα increases the Ca2+ sparklet activity in these cells. Consistent with this hypothesis we found that application of the PKC activator phorbol 12,13-dibutyrate (PDBu; 500 nM) increased Ca2+ sparklet activity in neonatal cardiac myocytes. Analysis of the spatial distribution Ca2+ sparklet activity was not random (i.e. did not have a Poisson distribution). Rather, as in reported in smooth muscle cells, Ca2+ sparklet activity was higher at specific regions of the cell. Translocation of PKCα to the sarcolemma of neonatal cardiac myocytes resulted in an increase in Ca2+ sparklet activity in specific regions of the cell. Data will be presented on the relationship between Ca2+ sparklet activity and Ca2+ release from the sarcoplasmic reticulum via ryanodine receptors (i.e. Ca2+ sparks) during excitation-contraction coupling. Our data suggest that Ca2+ sparklet (i.e. L-type Ca2+ channels) activity varies within the sarcolemma of neonatal cardiac myocytes and that they are modulated by PKCα, potentially regulating SR Ca2+ release during EC coupling in heart.
The chemistry of heterocycles. IV. 2H-pyrido[4,3-e]-1,3-oxazine-2,4(3H)-dione, its precursors and some 3-substituted derivatives.†‡

The preparation of 2H-pyrido[4, 3-e]-1, 3-oxazine-2, 4(3H)-dione (II) and the anisoyl, benzoyl, 4-chlorobenzoyl, trans-cinnamoyl, 3, 5-dinitrobenzoyl, 2-furoyl, and 2-naphthoyl derivatives substituted at position 3 of II together with their infrared and ultraviolet spectra are described. The 3-substituted 2 and 4-(2-pyridylethyl) and hydroxymethyl derivatives of quinolinimide and cinchomeronimide were also prepared and their spectra recorded.
Simultaneous generation of CD34+ primitive hematopoietic cells and CD73+ mesenchymal stem cells from human embryonic stem cells cocultured with murine OP9 stromal cells.

Objective Human embryonic stem cells (hESCs) have been shown to generate CD34 + primitive hematopoietic cells after several days of coculturing with the OP9 murine stromal cell line. CD73 + multipotent mesenchymal cells have also been isolated from hESC/OP9 cocultures after several weeks. We hypothesized that generation of CD34 + hematopoietic cells and CD73 + mesenchymal stem cells (MSCs) may follow similar kinetics, so we investigated the generation of CD73 + cells in the first 2 weeks of hESC/OP9 cocultures, at a time when CD34 + cells are generated. Materials and Methods We cocultured hESCs with OP9 cells and examined the time course of appearance of human CD34 + and CD73 + cells using flow cytometry. We tested the hematopoietic progenitor potentials of CD34 + cells generated using hematopoietic colony-forming assays, and the multipotent mesenchymal properties of CD73 + cells generated using in vitro differentiation assays. Results We observed that in the first 2 weeks of the hESC/OP9 coculture system CD34 + hematopoietic and CD73 + MSC generation follows a similar pattern. We sorted the CD34 + cells and showed that they can generate hematopoietic progenitor colonies. Starting with cocultured cells on day 8, and through an enrichment procedure, we also could generate a pure population of MSCs. These hESC-derived MSCs had typical morphological and cell surface marker characteristics of adult bone marrow-derived MSCs, and could be differentiated toward osteogenic, adipogenic, and chondrogenic cells in vitro, a hallmark property of MSCs. Conclusions OP9 cells when cocultured with hESCs support simultaneous generation of CD34 + primitive hematopoietic cells and CD73 + MSCs from hESCs.
TOF PET offset calibration from clinical data

In this paper, we present a timing calibration technique for time-of-flight positron emission tomography (TOF PET) that eliminates the need for a specialized data acquisition. By eliminating the acquisition, the process becomes fully automated, and can be performed with any clinical data set and whenever computing resources are available. It also can be applied retroactively to datasets for which a TOF offset calibration is missing or suboptimal. Since the method can use an arbitrary data set to perform a calibration prior to a TOF reconstruction, possibly of the same data set, one also can view this as reconstruction from uncalibrated data. We present a performance comparison with existing calibration techniques.
Statin treatment of adult human glial progenitors induces PPARγ-mediated oligodendrocytic differentiation

The statins have been proposed as possible therapeutic agents for a variety of autoimmune disorders, including multiple sclerosis. In a genomic screen, we found that glial progenitor cells (GPCs) of the adult human white matter expressed significant levels of the principal statin target, HMG-CoA reductase, as well as additional downstream members of the sterol synthesis pathway. We therefore asked if statin treatment might influence the differentiated fate of adult glial progenitor cells. To assess the functional importance of the sterol synthesis pathway to adult human glial progenitors, we used simvastatin or pravastatin to inhibit HMG-CoA reductase, and then assessed the phenotypic differentiation of the progenitors, as well as the molecular concomitants thereof. We found that both statins induced a dose-dependent induction of oligodendrocyte phenotype, and concomitant reduction in progenitor number. Oligodendrocyte commitment was associated with induction of the sterol-regulated nuclear co-receptor PPARgamma, and could be blocked by the specific PPARgamma antagonist GW9662. Thus, statins may promote oligodendrocyte lineage commitment by parenchymal glial progenitor cells; this might reduce the available progenitor pool, and hence degrade the long-term regenerative competence of the adult white matter.
“Yes We Can” or “Yes We Did”? Prospective and Retrospective Change in the Obama Presidency

The election of Barack Obama as the first African American president speaks to the progress made in fulfilling the promise of one nation for all people. Obama’s success reflects retrospective changes, such as the advent of viral technology, the mobilization of Black voters, and the shift toward tolerance in White racial attitudes, all of which allowed a strategic Obama campaign to make landmark gains. But are these changes permanent? Moreover, will these retrospective changes benefit future African American candidates seeking political office? On the other hand, following an extremely unpopular Bush administration, the Obama victory could reflect the prospective changes that many voters believed would follow, including the restoration of American credibility abroad, economic recovery, and the move toward a postracial state. Have Obama’s first 100 days fulfilled these prospective visions? And if so, will Obama’s actions in these areas prove advantageous to minority candidates who follow in his historic foo...
Petrology and chemistry of recent lavas in the northern Marianas: Implications for the origin of island arc basalts

Petrologic and chemical data are presented for samples from five volcanically active islands in the northern Marianas group, an intra-oceanic island arc. The data include microprobe analyses of phenocryst and xenolith assemblages, whole rock major and trace element chemistry including REE, and Sr isotope determinations (87Sr/86Sr=0.7034±0.0001). Quartz-normative basalt and basaltic andesite are the most abundant lava types. These are mineralogically and chemically similar to the mafic products of other intra-oceanic islands arcs. It is suggested, however, that they are not typical of the ‘island arc tholeiitic’ series, having Fe enrichment trends and K/Rb, for example, more typical of calc-alkaline suits. Major and trace element characteristics, and the presence of cumulate xenoliths, indicate that extensive near surface (< 3 Kb) fractionation has occurred. Thus, even least fractionated basalts have low abundances of Mg, Ni and Cr, and high abundances of K and other large cation, imcompatible elements, relative to ocean ridge tholeiites. However, abundances of REE and small cation lithophile elements, such as Ti, Zr, Nb, and Hf are lower than typical ocean ridge tholeiites. The REE data and Sr isotope compositions suggest a purely mantle origin for the Marianas island arc basalts, with negligible input from subducted crustal material. Thus, subduction of oceanic lithosphere may not be a sufficient condition for initiation of island arc magmatism. Intersection of the Benioff zone with an asthenosphere under appropriate conditions may be requisite. Element ratios and abundances, combined with isotopic data, suggest that the source for the Marianas island arc basalts is more chondritic in some respects, and less depleted in large cations than the shallow (?) mantle source for ocean ridge tholeiites.
Mitochondrial citric acid cycle and related enzymes: adaptive response to exercise.

Abstract The levels of activity of citrate synthase and of DPN-specific isocitrate dehydrogenase increased 2-fold in muscles of rats subjected to a program of running. A parallel increase occurred in the concentration of cytochrome c and in the level of activity of succinate dehydrogenase. In contrast, glutamate dehydrogenase activity increased approximately 35%, while the levels of α-ketoglutarate dehydrogenase and mitochondrial malate dehydrogenase increased 50%. These findings provide evidence that, unlike the constituents of the respiratory chain, the mitochondrial citric acid cycle and citric acid cycle related enzymes do not increase in parallel during the adaptive response of skeletal muscle to exercise, resulting in a change in mitochondrial composition.
Shape of ammonium chloride dendrite tips at small supersaturation

Abstract We report detailed shape measurements of the tips of three-dimensional NH 4 Cl dendrites grown from supersaturated aqueous solution. For growth at small supersaturation, we compare two models for the tip shape: parabolic with a fourth-order correction and a power law. Neither is ideal, but the fourth-order fit appears to provide the most robust description of both the tip shape and position for this material. For that fit, the magnitude of the fourth-order coefficient is about half of the theoretically expected value.
Effects of Mutations in the γ-Phosphate Binding Site of Myosin on Its Motor Function

The role of the highly conserved residues in the γ-phosphate binding site of myosin upon myosin motor function was studied. Each of five residues (Ser181, Lys185, Asn235, Ser236, and Arg238) in smooth muscle myosin was mutated. K185Q has neither a steady state ATPase nor an initial Pi burst. Although ATP and actin bind to K185Q, it is not dissociated from actin by ATP. These results indicate that the hydrolysis of bound ATP by K185Q is inhibited. S236T has nearly normal basal Mg2+-ATPase activity, initial Pi burst, ATP-induced enhancement of intrinsic tryptophan fluorescence, and ATP-induced dissociation from actin. However, the actin activation of the Mg2+-ATPase activity and actin translocation of S236T were blocked. In contrast S236A has nearly normal enzymatic properties and actin-translocating activity. These results indicate that 1) the hydroxyl group of Ser236 is not critical as an intermediary of proton transfer during the ATP hydrolysis step, and 2) the bulk of the extra methyl group of the threonine residue in S236T blocks the acceleration of product release from the active site by actin. Arg238, which interacts with Glu459 at the Switch II region, was mutated to Lys and Ile, respectively. R238K has essentially normal enzymatic activity and motility. In contrast, R238I does not hydrolyze ATP or support motility, although it still binds ATP. These results indicate that the charge interaction between Glu459 and Arg238 is critical for ATP hydrolysis by myosin. Other mutants, S181A, S181T, and N235I, showed nearly normal enzymatic and motile activity.
Attitude similarity-dissimilarity and attraction: generality beyond the college sophomore.

(1969). Attitude Similarity-Dissimilarity and Attraction: Generality Beyond the College Sophomore. The Journal of Social Psychology: Vol. 79, No. 2, pp. 155-161.
Energy component analysis of rotational barriers

Abstract The energy components, V att  V ne and V rep  T ÷ V nn ÷ V ee are employed in the analysis of the barrier mechanism. Molecules treated are: CH 3 CH 3 , CH 3 NH 2 , CH 3 OH, CH 3 CH 2 F, CH 3 CHO, CH 3 CHCH 2 , H 3 BNH 3 , NH 2 NH 2 , NH 2 OH, HOOH, HONO, and HOCHO.
Effect of Centrally Located Samples in the Integrating Sphere

The radiance distribution on the wall of an integrating sphere having a centrally located sample is analyzed. The radiance of the sphere wall is found as a function of the angular position inside the sphere. The analysis assumes mixed reflectance for the samples. It takes into account the effect of (1) the size of the sample relative to the sphere, (2) the average diffuse reflectance of the sphere wall, (3) the reflectance of the back face of the sample, and (4) the angle of incidence of the reference beam incident on the sample. The analysis considers the effect of the radiant exchange between the sample, its back, and the sphere wall. It allows also for the shadow of the sample on the sphere wall. The radiance distribution inside the sphere is found in case the reference beam does not hit the sample directly upon its entry into the sphere (this is useful in the absolute-reflectance-measurement technique). It is also derived when the sample is in the way of the reference beam. The expressions found for the radiance distribution allow accurate estimation of the errors due to the effect of centrally located samples in integrating sphere in reflectance measurements. The effects of the different factors involved in the interaction between the sample and the sphere wall can be seen from radiance-distribution expressions and would be of use in design of integrating-sphere reflectance-measurement systems. An example of the estimation of errors due to the effect of a centrally located sample inside an integrating sphere, in the measurement of mixed reflectance, is demonstrated.
Thermal criteria for tundish nozzle or taphole blockage

A formulation is presented to describe the rate at which a solidified crust is formed (and possibly remelted) on the inside walls of a nozzle through which molten metal is being poured. The molten metal stream is considered to be turbulent and in the formulation allowance is made for transient heat conduction in the skull and in the refractory walls, together with the time dependent mass flow rate due to the presence of the skull. The resultant differential equations are solved numerically and computed results are presented for conditions that are thought representative of some tundish pouring practices. It was found that the growth and possible remelting of the solidified crust would take place very rapidly, in a matter of seconds. The effect of several parameters was examined, including the role played by the nozzle diameter, the superheat of the steel and the preheating of the nozzle walls. It was found that the nozzle diameter was the most critical variable; nozzles less than about 1/2 in. in diam were likely to freeze rather readily. The superheat of the steel was found important in affecting closure, but the preheat of the nozzle appeared to be less significant a variable, provided the nozzle was brought within about 500‡F of the freezing temperature of the steel.
Incentive Level Influence on Overt Rehearsal and Free Recall as a Function of Age.

Abstract Two studies were conducted to test incentive magnitude effects on free recall. Experiment I examined whether two incentive levels would differentially influence rehearsal of words paired with the incentive values. Fifth and eighth graders and college adults were tested in conditions in which they were instructed to (a) do all rehearsal overtly or (b) engage in a counting task subsequent to item presentation and refrain from overt and covert rehearsal. College subjects rehearsed and recalled significantly more 10¢ than 1¢ words. Eighth graders tended to favor 10¢ items in recall and rehearsal, but the differences were of questionable reliability. Fifth graders failed to produce reliable Incentive Level effects. Experiment II showed that fifth graders, as well as older subjects, recalled more high-incentive words under standard free-recall instructions in which rehearsal was presumed to be covert. Results support theories emphasizing rehearsal as a mediator of incentive level effects on learning.