cssi/SciSciGPT-SciSciNet huggingface dataset:
The Sixteenth International Mathematical Olympiad and Some Implications.

For the past three years, the Mathe matical Association of America has con ducted the U.S.A. Mathematical Olym piad. (Reports on these Olympiads have appeared in the March 1973, February 1974, and January 1975 issues of the Mathematics Teacher.) On 1 April 1974, the United States received an invitation to participate in the Sixteenth International Mathematical Olympiad, to be held in Erfurt, in the German Democratic Re public, on 8 and 9 July 1974. The invita tion was extended to the U.S. Commission on Mathematical Instruction by the G.D.R., the host nation for this year. The U.S. Olympiad Committee was not entirely unprepared for this invitation, as unofficial word had come to us from the U.S.S.R., the Netherlands, and Great Britain that an invitation to participate would be forthcoming. The committee had decided to select a team of eight students who had scored high on the U.S.A. Olym piad. A grant had been received from the National Science Foundation to fund a three-week training period for the team. The Spencer Foundation of Chicago, Illinois, provided $5,000 to cover travel expenses to and from Europe for the team of eight students, one director, and one secretary. Other minor miracles took care of passports and visas and, on 4 July, we arrived in Erfurt. Our experiences in the G.D.R., while very interesting, will not be detailed here. Instead, we will concentrate on the In ternational Olympiad, the results ob tained, and the implications for the United States of these results. The Sixteenth International Mathe matical Olympiad took place on 8 and 9 July 1974. Each day, three problems were presented and four and one-half hours given to solve them. The Olympiad prob lems follow.
Effects of Chronic Neutral Endopeptidase Inhibition on the Progression of Left Ventricular Dysfunction and Remodeling in Dogs with Moderate Heart Failure

Background. The diuretic actions of endogenously produced atrial natriuretic factor (ANF) may be beneficial in the treatment of chronic heart failure (CHF). Neutral endopeptidase (NEP) is the primary enzyme responsible for the degradation of ANF. The present study investigates the effects of long-term NEP inhibition on the progression of left ventricular (LV) dysfunction and remodeling in dogs with moderate heart failure. Methods. LV dysfunction was produced in 12 dogs by multiple sequential intracoronary microembolizations. Embolizations were discontinued when LV ejection fraction (EF) was between 30–40%. Two weeks after the last embolization, dogs were randomized to 3 months of oral therapy with the NEP inhibitor ecadotril (100 mg, once daily, n = 6) or to no therapy at all (control, n = 6). Results. During the 3 months of follow-up, LV EF in control dogs decreased from 37 ± 1% to 28 ± 1% (P < 0.01) and LV end-diastolic volume (EDV) and end-systolic volume (ESV) increased (EDV: 72 ± 3 vs. 84 ± 5 ml, P < 0.01); ESV: 45 ± 1 vs. 60 ± 4 ml, P < 0.01). In dogs treated with ecadotril, LV EF (34 ± 1% vs. 37 ± 2%), EDV (79± 5 vs. 78± 6 ml) and ESV (52 ± 3 vs. 49 ± 4) remained essentially unchanged after 3 months of therapy. Histomorphometric measurements at the termination of the study showed that ecadotril was associated with significantly reduced cardiomyocyte hypertrophy compared to control. Conclusion. Early, long-term NEP inhibition with ecadotril prevents the progression of LV dysfunction and attenuates progressive LV remodeling in dogs with moderate heart failure.
Implications of the severe acute respiratory syndrome associated with the novel coronavirus-2 on vascular surgery practices.

Abstract Background We sought to understand the effects of coronavirus disease-2019 (COVID-19) on vascular surgery practices as related to the Vascular Activity Condition (VASCON) scale. Methods All members of the Vascular and Endovascular Surgery Society were surveyed on the effects of COVID-19 in their practices, educational programs, and self-reported grading of their surgical acuity level using the VASCON scale. Results Total response rate was 28% (206/731). Most respondents (99.5%) reported an effect of COVID-19 on their practice, and most were VASCON3 or lower level. Most reported a decrease in clinic referrals, inpatient/emergency room consults, and case volume (P Conclusions Nearly all vascular surgeons studied are affected by the COVID-19 pandemic with decreased clinical and operative volume, educational opportunities for trainees, and compensation issues. The VASCON level may be helpful in determining surgical readiness.
Neurologic effects of short-term treatment with a soluble epoxide hydrolase inhibitor after cardiac arrest in pediatric swine

Cardiac arrest (CA) is the most common cause of acute neurologic insult in children. Many survivors have significant neurocognitive deficits at 1 year of recovery. Epoxyeicosatrienoic acids (EETs) are multifunctional endogenous lipid signaling molecules that are involved in brain pathobiology and may be therapeutically relevant. However, EETs are rapidly metabolized to less active dihydroxyeicosatrienoic acids by soluble epoxide hydrolase (sEH), limiting their bioavailability. We hypothesized that sEH inhibition would improve outcomes after CA in an infant swine model. Male piglets (3–4 kg, 2 weeks old) underwent hypoxic-asphyxic CA. After resuscitation, they were randomized to intravenous treatment with an sEH inhibitor (TPPU, 1 mg/kg; n = 8) or vehicle (10% poly(ethylene glycol); n = 9) administered at 30 min and 24 h after return of spontaneous circulation. Two sham-operated groups received either TPPU (n = 9) or vehicle (n = 8). Neurons were counted in hematoxylin- and eosin-stained sections from putamen and motor cortex in 4-day survivors. Piglets in the CA + vehicle groups had fewer neurons than sham animals in both putamen and motor cortex. However, the number of neurons after CA did not differ between vehicle- and TPPU-treated groups in either anatomic area. Further, 20% of putamen neurons in the Sham + TPPU group had abnormal morphology, with cell body attrition and nuclear condensation. TPPU treatment also did not reduce neurologic deficits. Treatment with an sEH inhibitor at 30 min and 24 h after resuscitation from asphyxic CA does not protect neurons or improve acute neurologic outcomes in piglets.
Experimental determination of solubilities of tri-calcium di-citrate tetrahydrate [Ca3[C3H5O(COO)3]2∙4H2O], earlandite, in NaCl and MgCl2 solutions to high ionic strengths

Abstract In this study, solubility measurements on tri-calcium di-citrate tetrahydrate [Ca3[C3H5O(COO)3]2•4H2O, abbreviated as Ca3[Citrate]2•4H2O, earlandite] as a function of ionic strength are conducted in NaCl solutions up to I = 5.0 mol kg−1 and in MgCl2 solutions up to I = 7.5 mol kg−1, at room temperature (22.5 ± 0.5 °C). The solubility constant ( log K s p 0 ) for Ca3[Citrate]2•4H2O and formation constant ( log β 1 0 ) for Ca[C3H5O(COO)3]–, (1) Ca3[C3H5O(COO)3]2•4H2O (earlandite) = 3Ca2+ + 2[C3H5O(COO)3]3– + 4H2O (2) Ca2+ + [C3H5O(COO)3]3– = Ca[C3H5O(COO)3]– are determined as −18.11 ± 0.15 and 4.97 ± 0.15, respectively, with a set of Pitzer parameters describing the specific interactions in NaCl-bearing and MgCl2-bearing media. The solubility measurements and thermodynamic modeling indicate that earlandite could become a solubility-controlling phase for citrate in the near field of geological repositories for nuclear waste when the inventories of citrate reach the saturation concentrations for Ca3[Citrate]2•4H2O, and it is a solubility-limiting phase for calcium/citrate in other low temperature environments such as agro-food industrial waste-waters. The Pitzer model presented in this work will enable researchers to assess the role of citrate in low temperature environments over a wide range of ionic strengths, and is expected to find applications in many fields such as food and pharmaceutical sciences, cement and concrete industries as well as nuclear waste management.
Risk factors and outcomes for delayed kidney graft function in simultaneous heart and kidney transplant recipients: A UNOS/OPTN database analysis

There are no prior studies assessing the risk factors and outcomes for kidney delayed graft function (K-DGF) in simultaneous heart and kidney (SHK) transplant recipients. Using the OPTN/UNOS database, we sought to identify risk factors associated with the development of K-DGF in this unique population, as well as outcomes associated with K-DGF. A total of 1161 SHK transplanted between 1998 and 2018 were included in the analysis, of which 311 (27%) were in the K-DGF (+) group and 850 in the K-DGF (-) group. In the multivariable analysis, history of pretransplant dialysis (OR: 3.95; 95% CI: 2.94 to 5.29; p < .001) was significantly associated with the development of K-DGF, as was donor death from cerebrovascular accident and longer cold ischemia time of either organ. SHK recipients with K-DGF had increased mortality (HR: 1.99; 95% CI: 1.52 to 2.60; p < .001) and death censored kidney graft failure (HR: 3.51; 95% CI: 2.29 to 5.36; p < .001) in the multivariable analysis. Similar outcomes were obtained when limiting our study to 2008-2018. Similar to kidney-only recipients, K-DGF in SHK recipients is associated with worse outcomes. Careful matching of recipients and donors, as well as peri-operative management, may help reduce the risk of K-DGF and the associated detrimental effects.
The influence of inferior vena cava compression on the level of spinal anesthesia.

Abstract It is well known that the pregnant patient requires less anesthetic agent for induction of spinal anesthesia than does the nonpregnant patient. The purpose of this study was to demonstrate that compression of the inferior vena cava by the pregnant uterus or by an abdominal binder causes engorgement of the vertebral venous system, which in turn decreases the capacity of the spinal subarachnoid space for spinal fluid. Therefore, a smaller quantity of anesthetic agent would be required to induce spinal anesthesia. A spinal anesthetic was administered under standard conditions to 20 nonpregnant patients, 15 pregnant patients at term, and 15 nonpregnant patients in whom the inferior vena cava pressure was artificially increased to approximately 250 mm. of water. The results indicated that an increase in inferior vena cava pressure causes a decreased requirement for anesthetic agent for the induction of spinal anesthesia.
Serum IgA to Epstein‐Barr virus Early Antigen‐Diffuse identifies Hodgkin's lymphoma

Hodgkin's lymphoma is associated with immune dysregulation. Immune impairment often results in aberrant immune responses and lytic reactivation of ubiquitous Herpesviruses, such as Epstein-Barr virus (EBV) in mucosal tissues. Accordingly, the specificity of IgA to EBV early lytic antigens, which are important for reactivation, was evaluated to determine Hodgkin's lymphoma-specific sero-reactive patterns. Sera from 42 patients with Hodgkin's lymphoma were compared to sera from 17 patients with infectious mononucleosis (IM), another EBV-related condition that often presents in a similar manner; and to sera from 15 healthy EBV-seropositive subjects. Flow cytometry analysis demonstrated that like IM sera, most Hodgkin's lymphoma sera contained IgA that labeled cells expressing EBV early lytic antigens whereas healthy EBV-seropositive sera did not. Further evaluation to distinguish Hodgkin's lymphoma from IM showed that IgA in most Hodgkin's lymphoma, irrespective of the presence of EBV in primary tumors, detected only modified forms of EBV lytic Early Antigen-Diffuse (EA-D) while IM sera detected the un-modified form as well, further supporting the presence of immune dysregulation in Hodgkin's lymphoma patients. This IgA pattern distinguished Hodgkin's lymphoma from IM sera with a sensitivity of 92.9%, specificity 100%, positive predictive value 100%, and negative predictive value 85%. Our findings lay the groundwork for additional scientific and clinical investigation, particularly into the potential for developing Hodgkin's lymphoma-associated diagnostic and prognostic biomarkers.
Computational and experimental investigation of constitutive behavior in AraC

Many mutations in the N-terminal arm of AraC result in constitutive behavior in which transcription of the araBAD genes occurs even in the absence of arabinose. To begin to understand the mechanism underlying this class of mutations, we used molecular dynamics with self-guided Langevin dynamics to simulate (1) wild-type (WT) AraC, (2) known constitutive mutants resulting from alterations in the regulatory arm, particularly alanine and glycine substitutions at residue 8 because P8G is constitutive, whereas P8A behaves like wild type, and (3) selected variant AraC proteins containing alterations in the dimerization core. In all of the constitutive arm mutants, but not the WT protein, residues 37-42, which are located in the core of the dimerization domain, became restructured. This raised the question of whether or not these structural changes are an obligatory component of constitutivity. Using molecular dynamics, we identified alterations in the core that produced a similar restructuring. The corresponding mutants were constructed and their ara constitutivity status was determined experimentally. Because the core mutants were not found to be constitutive, we conclude that restructuring of core residues 37-42 does not, itself, lead to constitutivity of AraC. The available data lead to the hypothesis that the interaction of the N-terminal arm with something other than the front lip is the primary determinant of the inducing versus repressing state of AraC.
Piezoelectric PZT tubes and fibers for passive vibrational damping

Passive vibrational damping was demonstrated in piezoelectric lead zirconate titanate (PZT) tubes incorporated into a hard epoxy matrix. For a poled tube, the coupling constant k/sub 33/, measured from the resonance frequency, was about 0.66. Sol-gel methods were used to fabricate piezoelectric fibers of Pb(Zr/sub 0.52/Ti/sub 0.48/)O/sub 3/ and niobium- and CdBO/sub 3/-substituted PZT. Continuous and fine gel fibers of about 5 to 100 mu m in diameter were prepared by extruding and drawing spinnable viscous resins through a spinnaret. When fired at 600 degrees C for 1 h, these fibers exhibited well-crystallized perovskite phases of PZT. Fibers fired between 700 degrees and 1250 degrees C were dense with varying grain sizes (0.1 to 5 mu m). The dielectric constant of Pb(Zr/sub 0.52/Ti/sub 0.48/)O/sub 3/ fiber that was fired at 700 degrees C for 1 h was about 800. These fibers will be incorporated into structural materials to obtain maximum damping properties. >
Adipocyte Differentiation and Gene Expression

The major function of adipocytes is to store triacylglycerol in periods of energy excess and to mobilize this energy during times of deprivation. The short-term control of these lipogenic and lipolytic processes is carefully modulated by hormonal signals from the bloodstream, which provide an inventory of the body's metabolic state. Long-term changes in fat storage needs are accomplished by altering both the size and number of fat cells within the body because terminally differentiated adipocytes cannot divide. Alterations in the number of fat cells within the body must be accomplished by the differentiation of preadipocytes, which act as the renewable source of adipocytes. Our understanding of the events that occur during preadipocyte differentiation has advanced considerably in the last few years and has relied mainly on the use of tissue culture models of adipogenesis. This article will discuss the various models used for studying the preadipocyte differentiation process, with the mouse 3T3-L1 cell culture line described in detail. We focus on those genetic events that link effectors to induction of adipocyte gene expression.
Formation and degradation of dichloroacetonitrile in drinking waters

Dichloroacetonitrile (DCAN) is an important example of a reactive disinfection by-product for which a large body of occurrence data exists. Although it is known to undergo base-catalysed hydrolysis, DCAN9s peculiar dependence on reaction time, chlorine dose and pH has never been fully reconciled with expectations based on its presumed precursor (i.e. amino acid residues). The purpose of this research was to improve existing models for DCAN degradation and to use this information for interpretation of DCAN concentration profiles. Laboratory studies were performed using buffered solutions of DCAN, natural organic matter (NOM) and treated drinking waters, both with and without free residual chlorine. DCAN concentrations were measured as a function of reaction time. Results indicate a decomposition scheme encompassing three pathways of hydrolysis: attack by hydroxide, hypochlorite and water. Any one of the three pathways may predominate in drinking water systems, depending on the pH and chlorine residual. The resulting chemical kinetic model was used to show that the DCAN formed (and subsequently decomposed) was often many times the actual measured DCAN concentration. DCAN formation was found to agree with expectations based on the underlying chemistry of chlorine attack on proteinaceous material.
The Connected Learner: Design patterns for transforming computing and informatics education

The Connected Learner is a re-orientation of undergraduate computing and informatics education to focus on student learning that connects to peers, the profession, and the community. The vision for this project is to transform the student entering an undergraduate computing and informatics program from a person with an interest in computing to a person with an identity as a computing professional. The project equally will transform the faculty attitude towards education, shifting their attitudes and behaviors away from mere knowledge transmission and lecturing toward a refreshed approach of developing educational activities that scaffold the computing knowledge and skills to build successful computing professionals. The project will catalyze and sustain this transition with the identification of pedagogical design patterns for The Connected Learner to guide all faculty in teaching courses in the undergraduate computing and informatics curriculum. The intellectual merit comprises innovative teaching and assessment practices across an entire undergraduate computing and informatics curriculum demonstrating the applicability and efficacy of these practices across a student body diverse in terms of socio-economic status and demographics. The project will develop taxonomies and design patterns for knowledge and assessment to facilitate scaling and disseminating educational innovation in computing. Additionally, the project will examine the key factors in building a sustainable practice of educational innovation, which includes faculty attitudinal shifts and infrastructures to support and sustain learning practices.
The role of perinatal brain damage in developmental disabilities: An epidemiologic perspective

To examine the potential contribution of epidemiologic research to the identification of perinatal brain damage as a “cause” of developmental disabilities, the authors review definitions and methods used in this field. The current literature provides considerably different estimates of the population prevalence of mental retardation (3–40 per thousand), cerebral palsy (1.2–2.6 per thousand), and learning disabilities (33–65 per thousand). Furthermore, the presumable proportion of disabilities caused in the perinatal period also differs with the population under investigation, age at examination, and exposure and outcome definition. Approximately 8–43% of cerebral palsy and 10–25% of mental retardation may be associated with variables describing perinatal morbidity usually interpreted as indicators of brain damage. The authors discuss the recent literature on the association of developmental disabilities and proxy variables, e.g., abnormal neuroimaging results, so-called asphyxia, abnormal fetal heart rate patterns or thyroxine levels, and severity of illness scores. Exact definitions of exposure and outcome, a proper study design, and agreement of findings from multiple studies are needed before associations between perinatal brain damage and developmental disabilities should be accepted as causal. MRDD Research Reviews 3:13–21, 1997. © 1997 Wiley-Liss, Inc.
The Caregiver as Part of the Dementia Management Team

Care for older people with dementia living in the community involves not only a physician and the patient, but also a family member as the ‘primary caregiver’. This caregiver communicates medical information from the physician to the patient (screening this information as necessary), ensures that treatment plans are carried out, and relays patient (and family) concerns to the physician. Optimal patient care depends, in part, on inclusion of such caregivers in the dementia management team. However, review of the literature suggests that physicians do not make optimal use of family members as partners in disease management. Further research is required to assess the effect of efforts to include family caregivers as part of the dementia management team and to determine how best to support family members in their role as partners in dementia management.
Proteolysis of protein C in pooled normal plasma and purified protein C by activated protein C (APC).

Abstract Protein C is a vitamin-K dependent zymogen of the anti-coagulant serine protease activated protein C (APC). In this paper, we report four lines of evidence that APC can activate protein C in pooled normal plasma, and purified protein C. First, the addition of APC to protein C-deficient plasma supplemented with protein C produces a prolongation of the clotting time of plasma that is proportional to the amount of protein C. This behavior was observed with APC from the Chromogenix APC resistance kit (Dia Pharm, Franklin, OH, USA) and from APC derived from the thrombin activation of human protein C (Enzyme Research Laboratories, South Bend, IN, USA). Secondly, using immunoblotting after gel electrophoresis, the disappearance of epitopes for monoclonal antibodies that recognize protein C but not APC indicates a time course for the activation by APC of protein C in pooled normal plasma and protein C purified from plasma. Thirdly, the same time course for the disappearance of protein C specific epitope can be followed using ELISA. Finally, protein C can be activated by APC as indicated by the increase in APC specific synthetic substrate Tryp–Arg–Arg– p nitroaniline hydrolysis. Kinetic data indicate a value of 4.7±0.4 mM −1 s −1 for the activation of protein C by APC under physiological conditions and in the presence of calcium. These observations document that APC must function not only in the inactivation of activated factors V and VIII, but also in the activation of protein C. This additional action of APC may be important to consider more broadly because of APC in the treatment of sepsis.
TOTAL PLASMA HOMOCYSTEINE DETERMINATION USING ION-EXCHANGE CHROMATOGRAPHY

Plasma homocysteine level has been linked with the risk of occlusive vascular disease. Due to the presence of multiple forms of homocysteine, with the majority found as protein-bound homocysteine, and the interchanges among non-protein-bound homocysteines, the concern of analytical reliability for total plasma homocysteine has been raised. In this research, plasma samples are reduced by dithiothreitol to break disulfide linkages. The reduced samples are separated and analyzed for homocysteine and its related compounds by ion-exchange chromatography with post-column ninhydrin derivatization and spectrometric detection. The total homocysteine of plasma is determined as the sum of homocysteine, homocysteine thiolactone, homocystine, and cysteine-homocysteine disulfide.
A novel DPP6 isoform (DPP6-E) can account for differences between neuronal and reconstituted A-type K+ channels

The channels mediating most of the somatodendritic A-type K+ current in neurons are thought to be ternary complexes of Kv4 pore-forming subunits and two types of auxiliary subunits, the K+ channel interacting proteins (KChIPs) and dipeptidyl-peptidase-like (DPPL) proteins. The channels expressed in heterologous expression systems by mixtures of Kv4.2, KChIP1 and DPP6-S resemble in many properties the A-type current in hippocampal CA1 pyramidal neurons and cerebellar granule cells, neurons with prominent A-type K+ currents. However, the native currents have faster kinetics. Moreover, the A-type currents in neurons in intermediary layers of the superior colliculus have even faster inactivating rates. We have characterized a new DPP6 spliced isoform, DPP6-E, that produces in heterologous cells ternary Kv4 channels with very fast kinetics. DPP6-E is selectively expressed in a few neuronal populations in brain including cerebellar granule neurons, hippocampal pyramidal cells and neurons in intermediary layers of the superior colliculus. The effects of DPP6-E explain past discrepancies between reconstituted and native Kv4 channels in some neurons, and contributes to the diversity of A-type K+ currents in neurons.
Mathematical representation of the vascular structure and applications

The complexity and diversity of the vascular system makes it difficult to perform quantitative blood vessel modeling and analysis. Emerging applications in biomedical modeling, bio-mimetic manufacturing and tissue engineering necessitate the development of new approaches to computational modeling of vascular structures. In this paper, we address the computational representation of realistic vascular objects to enable deformable blood vessels. First, we construct a swept volume based vascular model from a physiological vascular model. Second, we construct the NURBS surface based on deformable circles, i.e., the primitive of swept volume, as the boundary of the swept volumes. The approach of NURBS surface construction can also be extended to reconstruct medical image based vasclar models. In the end, potential applications of the mathematical representation of vascular structure including blood flow simulation in scaffold are discussed. As a computational representation, our vascular model enables multiscale visualization of a realistic vascular system.The work in this paper presents the initial steps toward creating computational models suitable for high-fidelity vascular modeling, design and analysis. The authors believe that improved computational modeling for biological structures will enable new applications in tissues engineering and biological analysis.
Proteomic Analysis of Coregulators Bound to ERα on DNA and Nucleosomes Reveals Coregulator Dynamics

Chromatin immunoprecipitation studies have mapped protein occupancies at many genomic loci. However, a detailed picture of the complexity of coregulators (CoRs) bound to a defined enhancer along with a transcription factor is missing. To address this, we used biotin-DNA pull-down assays coupled with mass spectrometry-immunoblotting to identify at least 17 CoRs from nuclear extracts bound to 17β-estradiol (E2)-liganded estrogen receptor-α on estrogen response elements (EREs). Unexpectedly, these complexes initially are biochemically stable and contain certain atypical corepressors. Addition of ATP dynamically converts these complexes to an "activated" state by phosphorylation events, primarily mediated by DNA-dependent protein kinase. Importantly, a "natural" ERE-containing enhancer and nucleosomal EREs recruit similar complexes. We further discovered the mechanism whereby H3K4me3 stimulates ERα-mediated transcription as compared with unmodified nucleosomes. H3K4me3 templates promote specific CoR dynamics in the presence of ATP and AcCoA, as manifested by CBP/p300 and SRC-3 dismissal and SAGA and TFIID stabilization/recruitment.
High-flux mitochondrial cholesterol trafficking, a specialized function of the adrenal cortex

The adrenal cortex is a tissue of excess in terms of both cholesterol metabolism and cholesterol exchange with the circulation. Exceptionally high levels of lipoprotein receptors in this highly vascularized tissue provide ready access to dietary cholesterol, allowing the adrenocortical cells to maintain impressive stores of cytoplasmic cholesterol ester (CE) droplets. Tightly packed among the CE droplets are specialized mitochondria, carrying in their inner membranes high levels of the cytochrome P450scc (CYP11A1). This enzyme carries out the so-called side chain cleavage reaction, consuming cholesterol to produce pregnenolone, the precursor of cortisol and all other steroids. Glucocorticoid synthesis is tightly regulated at the level of cholesterol metabolism, which responds to ACTH stimulation over a period of minutes and ceases equally quickly when this hormone is removed. Remarkably, this dynamic process is modulated under most circumstances not by control of the intrinsic enzymatic activity of P450scc, but rather by substrate availability. For this reason, cholesterol transport within the mitochondrion has emerged as the key control point for steroidogenesis. The adrenal cortex is not alone in requiring efficient and controlled delivery of cholesterol into mitochondria. Other steroidogenic cells, including several cell types in the ovary, the Leydig cells of the testis, and a subset of hippocampal neurons (1), also employ P450scc to produce pregnenolone and a variety of downstream steroid hormones or neurosteroids. In vertebrates ranging from birds and fish (2) to mammals, these various cell types all express a short-lived mitochondrial import factor now called the steroidogenic acute regulatory protein (StAR), which mediates this process. Here, I examine the often confusing literature on StAR’s mechanism of action, particularly in light of recent work establishing the importance of other players, and I present a model for StAR’s interaction with cholesterol and with some of these other proteins. I also discuss the insights into mitochondrial function that have come from the analysis of patients with congenital adrenal hyperplasia (CAH), who lack this factor. Finally, I consider the multi-tiered regulation of StAR and related proteins in adrenocortical cells and other steroidogenic cell types.
Generating pseudo-random variables from mixture models by exemplary sampling

Generating samples from a two-stage distribution is an important part of the study of mixture models. These samples are used to examine estimation procedures, and other properties of the mixture model. In this paper we present an exemplary sampling method for generating data from the mixed distribution. This method uses the order statistic spacings of the mixing distribution and random sampling from the distribution conditional on the mixing variable to produce samples from the mixed distribution. We show that this exemplary procedure often produces data with an empirical distribution function closer to the mixed distribution than the Method of Composition. We illustrate the method with an example.
Morphology of the seagull's inner ear.

The morphology of the seagull ear was investigated and found to be generally similar to that of other Aves. Several specific outer middle and inner ear features were found to be sufficiently different as to be remarkable. Most notably, the dual membranes of the external auditory meatus: one, a collecting (and possibly amplifying and reflecting) parabolic membrane chamber situated immediately anterior to the slightly deeper tympanic membrane. The convex tympanic membrane attaches a cartilagenous extracolumella and a thick osseous columella, which is less thin and fragile than that observed in domestic fowl of comparable body size. The columella footplate and round window are completely covered with a second middle ear membrane which apparently serves as an H2O seal and hydrostatic pressure matcher. The short, hard seagull cochlea houses an elaborate basilar papilla which contains thousands of short and tall hair cells, each with a systematic arrangement of stereocilia bundles. In the seagull, the length of...
Radiology and social media: are private practice radiology groups more social than academic radiology departments?

Abstract Purpose This study assesses the prevalence of use of the most commonly used social media sites among private radiology groups (PRGs) and academic radiology departments (ARDs). Methods The 50 largest PRGs and the 50 ARDs with the highest level of funding from the National Institutes of Health were assessed for presence of a radiology-specific social media account on Facebook, Twitter, Instagram, Pinterest, YouTube, and LinkedIn. Measures of organizational activity and end-user activity were collected, including the number of posts and followers, as appropriate; between-group comparisons were performed. Results PRGs adopted Facebook 12 months earlier ( P = .02) and Twitter 18 months earlier ( P = .02) than did ARDs. A total of 76% of PRGs maintained ≥1 account on the social media sites included in the study, compared with 28% of ARDs ( P Conclusions Use of social media in health care is emerging as mainstream, with PRGs being early adopters of Facebook and Twitter in comparison with ARDs. Competitive environments and institutional policies may be strong factors that influence how social media is used by radiologists at the group and department levels.
Indigenous Traditions and Ecological Ethics in Earth's Insights

Using the term, lifeway, this article emphasises the cosmology-cum-economy coherence of indigenous traditions. It explores the role of indigenous traditions in the formation of a global ecological ethic as put forward by J. Baird Callicott in his work, Earth's Insights. Recommending a cosmological approach, the article makes connections to advocacy issues. Finally, the significance of ordinary life in indigenous societies is foregrounded as the arena for teaching local ecological ethics.
Characterizing the Biaxial Mechanical Properties of Vaginal Maternal Adaptations During Pregnancy

Pelvic organ prolapse impacts the lives of many women. Injury during vaginal delivery is considered to be one of the greatest risk factors for developing this disorder. In this study, we characterized vaginal adaptations during pregnancy in terms of changes in the mechanical behavior of virgin and mid-pregnant vaginas using a planar biaxial mechanical testing protocol to determine the change necessary to avoid maternal birth injury. The findings of this study show that the vagina is anisotropic and that the tissue becomes more distensible circumferentially by mid-pregnancy in the rodent model.Copyright © 2010 by ASME
On theorems of minimum energy dissipation in magnetohydrodynamics

This paper is concerned with some theorems on the dissipation of energy in magnetohydrodynamics. It is shown that when certain conditions, (2.21) or (2.27) of the text, are satisfied, the steady motion of an electrically conducting incompressible fluid has an absolute minimum of energy dissipation. Furthermore, when the same conditions are satisfied, an unsteady motion with steady boundary conditions always tends to its steady state, which is stable as well as unique. The present theorems are also applicable to ordinary hydrodynamics and magnetohydrostatics. A brief implication of these theorems is discussed.
Effect of sway on image fidelity in whole-body digitizing

For 3D digitizers to be useful data collection tools in scientific and human factors engineering applications, the models created from scan data must match the original object very closely. Factors such as ambient light, characteristics of the object's surface, and object movement, among others can affect the quality of the image produced by any 3D digitizing system. Recently, Cyberware has developed a whole body digitizer for collecting data on human size and shape. With a digitizing time of about 15 seconds, the effect subject movement, or sway, on model fidelity is an important issue to be addressed. The effect of sway is best measured by comparing the dimensions of an object of known geometry to the model of the same object captured by the digitizer. Since it is difficult to know the geometry of a human body accurately, it was decided to compare an object of simple geometry to its digitized counterpart. Preliminary analysis showed that a single cardboard tube would provide the best artifact for detecting sway. A tube was attached to the subjects using supports that allowed the cylinder to stand away from the body. The stand-off was necessary to minimize occluded areas. Multiple scans were taken of 1 subject and the cylinder extracted from the images. Comparison of the actual cylinder dimensions to those extracted from the whole body images found the effect of sway to be minimal. This follows earlier findings that anthropometric dimensions extracted from whole body scans are very close to the same dimensions measured using standard manual methods. Recommendations for subject preparation and stabilization are discussed.
Preparation of vanadium- and chromium-substituted KIT-1 disordered mesoporous materials by direct incorporation

Abstract Vanadium- and chromium-substituted KIT-1 mesoporous materials were prepared by a direct hydrothermal synthesis for the first time and characterized by nitrogen physical adsorption, X-ray diffraction (XRD), and X-ray absorption near edge structure (XANES). These materials show narrow pore size distributions centered at 3.77 nm for V-KIT-1 and 3.37 nm for Cr-KIT-1 and high surface areas obtained from N 2 adsorption and desorption isotherms, which suggests that the incorporation of metal atoms does not much affect the mesoporous structure. It was determined from the XRD patterns that all samples had the KIT-1 disordered mesoporous structure. The pre-edge peak was observed in the XANES at the V and Cr K absorption edge, respectively, which suggests that V and Cr atoms have a tetrahedral coordination in the framework of the KIT-1 mesoporous material.
A constrained resource allocation study for LOS MIMO fading ad-hoc networks

We study constrained resource allocation problems for MIMO wireless ad-hoc networks under LOS fading. By considering the tradeoff between the aggregate consumed power and throughput of such networks, we investigate the performance characteristics of a number of MIMO coding techniques, namely MRC, STBCs, and orthogonal STTCs. Our study shows that utilizing space-time coding techniques can decrease the power consumption and/or increase the achievable throughput of ad-hoc networks under loss constraints
The assay of hydrazine mononitrate as a base in acetic acid

Hydrazine mononitrate has been determined as a base by non-aqueous titration in glacial acetic acid. The titrant was 0.05 N perchloric acid in glacial acetic acid which must be prepared without acetic anhydride. Small amounts of water increase the solubility of hydrazine nitrate, but reduce the sensitivity of the method.
Corporal punishment and student outcomes in rural schools

This study examined the effects of corporal punishment on student outcomes in rural schools by analyzing 1,067 samples from the School Survey on Crime and Safety 2007–2008. Results of descriptive statistics and multivariate regression analyses indicated that schools with corporal punishment may decrease students’ violent behaviors and increase the attendance rate, yet those schools may have more student insubordination incidents and fewer students with academic aspirations than schools without corporal punishment. All the associations in the results remained after controlling for school background characteristics. Rural school leaders should consider whether corporal punishment maximizes students’ educational benefits.
Testicular metamorphosis and prolongation of spermatogenesis in starlings (Sturnus vulgaris) in the absence of daily photostimulation

Male European starlings (Sturnus vulgaris) were held in constant darkness for 448 days. Testicular widths, measured in situ via unilateral laparotomy at two to four week intervals, revealed that testicular growth reached a size associated with spermatogenesis in an average of 101 days. The spermatogenic period persisted for an average of 296 days. Histological examination of testes from two birds after 280 days of treatment revealed mature sperm in the seminiferous tubules. Complete testicular involution did not occur. Current photoperiodic theory must be modified to explain testicular metamorphosis without daily photostimulation in an avian species known to be photoperiodic.
Duration of immunity in salmonids vaccinated by direct immersion with Yersinia ruckeri and Vibrio anguillarum bacterins

Abstract. The level of protective immunity was determined for several salmonid species following vaccination by the direct immersion method with commercial Vibrio anguillarum (two serotypes) and Yersinia ruckeri (Hagerman strain) bacterins. The duration of protective immunity varied with the bacterin concentration, size and species of fish, but the duration between the two bacterins was comparable. In fish under 1 g duration of protective immunity was longest when the most concentrated bacterin was used. Generally, immunity lasted in 1-g fish for about 120 days, in 2-g fish for about 180 days, but in 4-g fish and larger immunity lasted for a year or longer. Coho salmon (Oncorhynchus kisutch) and sockeye salmon (O. nerka) retained immunity for a longer time and pink salmon (O. gorbuscha) the shortest time. Chinook salmon (O. tshawytscha) and rainbow trout (Salmo gairdneri) were intermediate. Field data generally followed the laboratory tests, but the duration appeared somewhat shortened. In one test 20-g rainbow trout were vaccinated by the shower method and no loss of immunity occurred after 311 days.
Report On 15Th International Congress On High Speed Photography And Photonics

The 15th International Congress on High Speed Photography and Photonics was a gathering of international representatives who presented papers on the latest developnents on the use of high speed photography for scientific, industrial, research, medical and educational purposes.
Genetic Divergence among Northern Pike from Spawning Locations in the Upper St. Lawrence River

Abstract To assess the ecological consequences associated with the degradation of riparian wetlands that historically provided spawning and rearing habitat for northern pike Esox lucius, annual spawning migrations and genetic structure were used to examine this species' dependence on four specific spawning areas in the Thousand Islands region of the Saint Lawrence River. Tagging and recapture over three consecutive spawning seasons resulted in low return rates (ranging from 1.2% in bays to 8.3% in tributaries), and some exchange was observed between locations. Angler recaptures indicated that northern pike did not disperse widely; 72% were recaptured less than 2.5 km from their tagging location, though the remainder moved distances ranging from 2.5 to 18 km. Six microsatellite loci showed significant allele frequency differences and small but significant genetic differentiation (F ST) values among spawning sites in close proximity ( 20 km) were ...
Energy transfer in the photochemical apparatus of flashed bean leaves

Fluorescence and energy transfer properties of bean leaves greened by brief, repetitive xenon flashes were studied at -196 degrees C. The bleaching of P-700 has no influence on the yield of fluorescence at any wavelength of emission. The light-induced fluorescence yield changes which are observed in both the 690 and 730 nm emission bands in the low temperature fluorescence spectra are due to changes in the state of the Photosystem II reaction centers. The fluorescence yield changes in the 730 nm band are attributed to energy transfer from Photosystem II to Photosystem I. Such energy transfer was also confirmed by measurements of the rate of photooxidation of P-700 AT -196 degrees C in leaves in which the Photosystem II reaction centers were either all open or all closed. It is concluded that energy transfer from Photosystem II to Photosystem I occurs in the flashed bean leaves which lack the light-harvesting chlorophyll a/b protein.
Determining the significance of coagulase-negative staphylococci isolated from blood cultures at a community hospital: A role for species and strain identification

Objectives:To determine the degree to which species identification or strain relatedness assessment of successive blood culture isolates of coagulase-negative staphylococci (CNS) may improve the clinical diagnosis of bloodstream infection (BSI).Setting:400-bed community hospital.Design:Prospective laboratory survey during which all CNS blood culture isolates obtained between mid-August 1996 and mid-February 1997 (study period) were saved and later identified to the species level; selected isolates were genotyped using pulsed-field gel electrophoresis at the Centers for Disease Control and Prevention (CDC). Retrospective review of medical records of 37 patients with multiple cultures positive for CNS.Results:During the study period, 171 patients had blood cultures positive for CNS; 130 had single positive cultures and 41 had ≥2 positive cultures. Of these 41, 23 (62%) were from patients with signs and symptoms of BSI according to CDC surveillance definitions. Species identification and strain clonality of CNS isolates from patients with ≥2 positives revealed 3 (13%) of the 23 patients did not have a consistent CNS species, and another 3 (13%) did not have a consistent genotype in the ≥2 positive cultures, suggesting that CNS from these patients probably were contaminants. Thus, species identification and strain clonality assessment reduced by 27% the number of patients with BSI diagnosed based on the presence of symptoms and ≥2 positive blood cultures.Conclusions:Routine species identification and selected strain genotyping of CNS may reduce the misinterpretation of probable contaminants among patients with ≥2 positive blood cultures.
Current Concepts of Hip Arthroplasty for Radiologists: Part 1, Features and Radiographic Assessment

OBJECTIVE. This article will systematically review radiographic assessment of hip arthroplasty including classifications based on different types and techniques of hip arthro plasty, terminology for prosthetic designs and materials, surgical techniques, and initial and follow-up radiographic assessments. CONCLUSION. Assessment of postoperative hip arthroplasty radiographs is extremely important. It is well known that patients with complications may be asymptomatic, and for this reason, routine radiographic follow-up is recommended for all patients with hip arthroplasty. The foundation of radiologic interpretation of hip arthroplasty is knowledge of the normal appearance of the many different types of prostheses. A standard approach to radiologic reporting should be undertaken.
“Friendship” Interactions and Expression of Agitation among Residents of a Dementia Care Unit: Six-Month Observational Data

“Friendships” (ongoing interpersonal interactions) and agitated behavior were studied among 59 residents of a dementia special care unit; most residents had mild to moderate cognitive impairment. Behavior scan data were recorded by trained observers over six months. Three scans per hour were conducted, seven days a week, between 9 a.m. and 9 p.m., producing more than 17,000 observations. A marginal model for binary longitudinal data was developed to associate covariates with repeated observations of agitation, the dependent variable; generalized estimating equations were used to estimate regression parameters. Friendship behavior was significantly associated with (less) observed agitation in this group of dementia residents, controlling for additional variables expected to predict agitation. Opportunity for self-initiated interpersonal engagement may contribute significantly to the well-being of moderately impaired dementia residents. Repeated over-time assessments are important in understanding factors r...