cssi/SciSciGPT-SciSciNet huggingface dataset:
Insulated Railway Joint Design Methodology Through Parametric Finite Element Based Modeling

The Railroad Industry experiences multiple failures with currently used bonded insulated joint designs. These failures have encouraged an increased effort in strength and fatigue analysis for the joints. This paper presents a program initiated by Virginia Tech and Transportation Technology Center Incorporated (TTCI) to develop, analyze, and test a family of insulated joint designs featuring non-adhesive bolted connections. This program utilizes a hierarchical set of Finite Element (FE) parametric models that explore the problem’s mechanics for a family of rail joint design concepts by refining the analysis with each subsequent model. Currently, there is limited information concerning design criteria for insulated joints in the Railroad industry. Therefore, an initial task in this program is to define design criteria and representative load cases characteristic of typical life cycles for commercial freight rails. Design criteria are either proprietary to the railroad or do not appear to be published in the AREMA handbooks. However, the AREMA handbooks do define an acceptance test for the failure of rail joint. Failure criteria were derived from the AREMA rolling wheel acceptance test with some modifications to the magnitude of the loads. Using these load cases and design criteria, multiple FE models are used to identify the dominant mechanics of the bolted joint and contact problem. Each model features parametric relationships that enable rapid design changes including geometric features and mechanics. The development of hierarchical FE models facilitates the selection of a specific model that embodies the essential mechanics of the problem while maintaining a geometry that allows for parametric tradeoff studies. The design variables and baseline finite element model are used as an analysis tool developed as an Abaqus scripted template for design comparison studies. The hierarchical approach to finite element modeling with a parametric model has been applied to the development of a bolted insulated rail joint design, which has been realized in a new insulated joint prototype. The mechanics explored in the FE models can be verified using various full-scale load frame tests in a controlled environment. Tests are standardized across models using identical boundary conditions and load cases. The results obtained will be used to confirm modeling assumptions and provide necessary information for further prototype development. The prototype of the full 3-D geometry will be tested in track at TTCI for final design verification. The hierarchical parametric finite element modeling approach results in a tool that can be applied to joint design across the rail industry.Copyright © 2010 by ASME
Youths' health-related social problems: concerns often overlooked during the medical visit.

Abstract Objective The objectives of this study were to (1) measure the prevalence of health-related social problems among adolescent and young adult primary care patients; (2) estimate previous screening and referral experiences; and (3) examine participant attitudes toward screening and referral. Methods Data were collected as part of a cross-sectional study conducted in an urban young adult clinic. Patients aged 15 to 25 years completed a computerized questionnaire screening for health-related social problems in nine social domains. In addition, participants answered questions about their previous screening experiences, need for referrals, and their experience using the system. Results Seventy-six percent (304/401) of youth screened positive for at least one major problem, including healthcare access (37%), housing (34%), and food security (29%). Forty-seven percent (190/401) experienced major problems in two or more social domains. The prevalence of screening in the past year for each domain averaged 26%; 3% were screened in all nine domains in the previous 12 months and 33% were not screened in any domain. Overall, 75% needed a referral within the previous year, and 42% identified at least one unmet referral need. The majority (84%) of participants reported that it was acceptable to screen for these problems. Conclusion Prevalence of health-related social problems among youth is high. The majority needed at least one referral for a social need in the previous year. Primary care physicians would benefit from improved systems for screening and referral of health-related social problems in order to create a comprehensive medical home for their patients.
Ion chemistry in photon-dominated regions: Examining the [HCO +]/[HOC+]/[CO-] chemical network

HOC+ and CO+ have been detected toward two well-known photon-dominated regions (PDRs), S140 and NGC 2023, using the Arizona Radio Observatory 12 m telescope. The J = 1 → 0 transition of HOC+ at 89 GHz and the two spin components of the N = 2 → 1 line of CO+ near 236 GHz were observed, as well as the J = 1 → 0 transitions of H13CO+ and HC18O+. The J = 3 → 2 line of HOC+ at 268 GHz was also mapped across the Orion Bar. The [HCO+]/[HOC+] ratios determined in S140 and NGC 2023 were ~12,408 and 1913, respectively, values indicative of quiescent molecular gas rather than PDR sources, where the abundance of HOC+ is thought to be enhanced. However, the beam in both these measurements may contain material from the adjoining molecular cloud, favoring HCO+. Alternatively, the [HCO+]/[HOC+] ratio may vary with Av in PDR regions. The [CO+]/[HOC+] ratio in S140 and NGC 2023, at several positions in the Orion Bar, and in other PDRs, on the other hand, falls uniformly in the range ~1-10. In addition, the line profiles of CO+ and HOC+ in the Orion Bar look remarkably similar. The syntheses of HOC+ and CO+ appear to be correlated in PDRs, most likely through the common precursor, C+. The reaction of C+ and H2O is thought to preferentially create HOC+, as opposed to HCO+, and C+ + OH or O2 leads favorably to CO+.
The effect of the S14A mutation on the conformation and thermostability of Saccharomyces cerevisiae G-actin and its interaction with adenine nucleotides

The actin Ser14 hydroxyl is one of a number of ligands that binds to the gamma-phosphate of ATP thereby stabilizing the actin.ATP complex. In yeast actin, conversion of Ser14 to Ala (S14A), causes a temperature-sensitive phenotype in vivo and temperature-sensitive polymerization defects in vitro (Chen, X., and Rubenstein, P. A. (1995) J. Biol. Chem. 270, 11406-11414). Here, using a new luciferase-based procedure, we show that the mutation results in a 40-60-fold decrease in actin's affinity for ATP. The mutation causes a decrease in the intrinsic ATPase activity of both Ca- and Mg-G-actin at 30 degrees C and alters the protease susceptibility of sites on subdomain 2. Ca-S14A-actin but not Mg-S14A-actin binds etheno-ATP at 37 degrees C. Intrinsic tryptophan fluorescence measurements show that at 37 degrees C, Mg-S14A-actin but not the calcium form unfolds. CD measurements show the mutation causes a decrease in the apparent denaturation temperature for Ca-actin from 57 to 45 degrees C and for the magnesium form a decrease from 52 to 40 degrees C. Based on a re-examination of actin's crystal structure coordinates, we propose that the Ser14 hydroxyl forms a polar bridge between the ATP gamma-phosphate and the amide nitrogen of Gly74, thus conferring additional stability on the actin small domain.
Early- and Late-Lanthanide Pyridinethiolates: Synthesis, Redox Stability, and Structure.

The early and late lanthanides form stable complexes with the pyridinethiolate (2-S-NC5H4, or SPy) ligands. The Ce compound Ce(SPy)3 is relatively insoluble in neutral organic donor solvents such a...
Recovery of cognition from persistent vegetative state in a child with normal somatosensory evoked potentials.

The absence of bilateral early cortical SEPs in a PVS due to nontraumatic coma is usually associated with failure to recover cognition or awareness, although rarely patients with bilaterally absent cortical SEPs in posttraumatic PVS may regain cognition. On the other hand, normal cortical SEPs in nontraumatic coma may be related to favorable outcomes as shown in this patient and other reports. Our patient is unique in that he had had serial normal SEPs, was in a PVS for 7 1/2 months, and recovered cognition, but not without cost in terms of damage to intellectual capability. Further long-term clinical follow-up studies to correlate clinical outcome with serial SEP data may be indicated. Language: en
A knowledge management perspective to evaluation of enterprise information portals

The paper develops conceptual criteria for evaluating Enterprise Information Portal (EIP) systems in the context of knowledge management activities such as knowledge integration and application. The criteria have been drawn from an Activity theory perspective consisting of actors, community, object, tools, rules, and division of labor. It then discusses the characteristics of several commercial EIPs and evaluates one major commercial EIP in the context of the framework. Copyright © 2002 John Wiley & Sons, Ltd.
We've come this far by faith: Faith and spirituality as a facilitator to self-care management of type 2 diabetes among African-American men

Purpose: To explore and understand how the church, faith, and spirituality plays a role in type 2 diabetes management among African-American men (AA men). Materials and Methods: Participants ( n = 19) were AA men ages 35-69 years, who were diagnosed with type 2 diabetes. Participants were recruited via community outreach efforts, including barbershops and churches located in predominantly African-American communities in southeast US. Upon the consent, individual interviews were conducted, audio-recorded and subsequently transcribed. Transcripts were analyzed using a phenomenological approach, and focused on identifying common themes among the descriptions of AA men's experiences specific to type 2 diabetes. Results: Overall the participants from the present study stated that their faith in God as well as attending church does help them in their daily diabetes management. Interestingly, 2 of the 19 participants chose not to answer the faith and spirituality questions and 1 of the 19 stated that his faith was nonexistent. Conclusions: Diabetes self-management may be facilitated by incorporating the spiritual beliefs and virtues of AA men living with the illness. Little is still known, in general, about the process of how spirituality affects self-management of chronic illness. Further research should also focus on faith-based diabetes education among diabetics of all ethnic backgrounds.
Changes in composition and distribution of LDL subspecies in hypertriglyceridemic and hypercholesterolemic patients during gemfibrozil therapy

The effect of gemfibrozil (GEM) on composition and distribution of LDL subspecies in 10 hypertriglyceridemic (HTG) patients with triglyceride (TG) levels of 300-750 mg/dl and low density lipoprotein cholesterol (LDL-C) or = 190 mg/dl and TG < 200 mg/dl was investigated. Patients were randomized in a double-blind, crossover design to 12 week periods of placebo and 1200 mg/day GEM with an intervening washout period. All 7 LDL subspecies in the density range of 1.029 to 1.063 g/ml in the HTG group contained more TG (P < 0.01) and less free cholesterol (P < 0.05), while the proportion of cholesterol ester was lower only in LDL subspecies 1 to 3 (P < 0.05) as compared to the HC group. In HTG patients, GEM increased the proportion of cholesterol ester (P < 0.05) in all subfractions, while the proportion of free cholesterol was increased and TG was decreased in LDL subspecies 1 to 4 only (P < 0.05). GEM decreased the LDL subspecies score from 4.8 +/- 0.7 to 4.2 +/- 0.5, and the major LDL subclass density from 1.048 +/- 0.006 to 1.043 +/- 0.002 g/ml (P < 0.01) in HTG patients. GEM decreased TG levels to mean of 228 +/- 52 mg/dl in HTG patients, but there was no change in LDL phenotype. No significant changes in composition and distribution of LDL subspecies were noted in HC patients with GEM. We conclude that GEM significantly altered the composition and distribution of LDL subspecies with a shift from small dense LDL particles to large, less dense particles in HTG patients.
KRAS Mutation and Microsatellite Instability: Two Genetic Markers of Early Tumor Development That Influence the Prognosis of Colorectal Cancer

Introduction We examined two genetic markers established early in colorectal tumor development, microsatellite instability (MSI) and mutation of the KRAS proto-oncogene, to see if these genetic changes influence metastatic disease progression and survival.
Influence on 5-[3H]hydroxytryptamine binding site development in chick embryo by serotonergic compounds.

: Saturable and specific binding sites for 5-[3H]hydroxytryptamine (5-HT, serotonin) characterized by a KD of 3.5–4.5 nM were detected in the chick embryo brain and were shown to develop linearly as a function of age, weight, and protein content. Saturation and displacement studies using unlabeled 5-HT as the displacing ligand suggested a single population of binding sites. However, displacement studies using 5-methoxytryptamine, lysergic acid diethylamide (LSD), 2-bromo-lysergic acid diethylamide (BOL), methysergide, and spiperone as competing ligands suggested the existence of subclasses of [3H]5-HT binding sites because the Hill coefficients were less than unity. When compared with the reported [3H]5-HT binding sites (5-HT1) in the rat forebrain, the IC50 values of the competing ligands were similar. However, the Hill coefficients for LSD and methysergide were less than unity which suggested that the [3H]5-HT binding sites in the chick embryo brain may be more similar to those found in rat spinal cord than rat forebrain. To study [3H]5-HT binding site regulation and development, various serotonergic compounds were injected into the chorioallantoic fluid of the eggs at different times during embryonic development. Multiple pretreatments with d,l-5-hydroxytryptophan, 5-HT, or BOL were found to have no significant effects on either the affinity (KD) or number (Bmax) of specific [3H]5-HT binding sites. Multiple pretreatments with p-chlorophenylalanine were found to increase the Bmax of specific [3H]5-HT binding by 23% (p < 0.01) whereas multiple pretreatments with LSD were found to decrease the Bmax of specific binding by 45% (p < 0.01). Neither of these pretreatments affected KD values which indicated that only the number of specific [3H]5-HT binding sites was altered. Evidence was presented suggesting that these effects were probably not due to excess endogenous 5-HT or LSD remaining in the tissue preparation. The overall evidence indicated that the chick embryo brain may have a functioning serotonergic system and that the chick embryo may be an ideal system for the study of [3H]5-HT binding site regulation and development.
Adiabatic theory of symmetry breaking and dipole moments of isotopic molecules. Correct dissociation of their electronic and muonic ions.

To calculate the nonzero dipole moment of isotopic molecules such as HD or the correct dissociation limit of ions such as ${\mathrm{HD}}^{+}$ via the usual approach requires cumbersome, expansive nonadiabatic corrections to the Born-Oppenheimer approximation. Such a complication is herein shown unnecessary; the ``best adiabatic'' approximation of Pack and Hirschfelder [J. Chem. Phys. 52, 521 (1970)] provides a single straightforward formalism which gives such effects correctly and yet retains the potential energy curve concept. Simple example calculations show the size of these symmetry-breaking effects to be at the level of high-resolution spectroscopy for ${\mathrm{HD}}^{+}$ but very large in ions such as dt\ensuremath{\mu}, which contains a deuteron, a triton, and a negative muon.
Non-selective membranes for separations

Membranes which give high fluxes without selectivities provide a large interfacial area between fluid phases which is independent of the normal constraints of loading and flooding. These membranes offer a largely unexplored route to separation process intensification. Three examples are given in the paper. First, studies of hollow fiber blood oxygenators show that flows which are only a few percent from uniform can reduce overall mass transfer by an order of magnitude. Second, flat sheet membrane evaporators promise the performance of a centrifugal evaporator at a fraction of that unit's cost. Third, distillation in hollow fibers means that the height of the transfer units can be smaller than 0.1 cm, indeed as small as desired.
Effects of 1,25 dihydroxyvitamin D3 administration on circadian mineral rhythms in humans

1,25 Dihydroxyvitamin D3 (1,25(OH)2D3) (2.0 μg) was given intramuscularly to 6 healthy adult males. Twenty-four circadian patterns of blood-ionized calcium (Ca2+), serum phosphate (Pi), and total calcium (CaT) were assessed pre- and posthormone administration. Correlations of mean mineral rhythms with normative models were significant for each mineral pattern on both study days. Mean Ca2+ and CaT rhythms became weakly correlated after hormone treatment (r=.39). A small but statistically significant increment in the 24 h grand mean Ca2+ concentration was observed on the treatment day compared with the baseline day. However, this increment is less than the year-to-year variability in the grand mean mineral concentrations derived from the same subjects studied under baseline conditions previously. These data indicate that acute parenteral administration of near-physiological (2.0 μg) doses of 1,25(OH)2D3 appears to have no major effect on circadian mineral pattern shape or mean mineral concentrations.
Employment, structural adjustment and sustainable growth in Mexico

The impact of slow growth since the early 1980s on the Mexican labour market is analysed by comparing Mexico's employment performance to that of other OECD countries through three different components, that is, the labour force participation ratio, occupational structure and output per worker. The ‘old’ employment components of Mexico's development problem — low participation ratios and a high employment share of agriculture — have remained, to which is added a new employment problem in the form of a massive increase in underemployment in the tertiary sectors of the economy driving down wages for a large part of the population. This article raises two sets of questions. First, given the current employment problems and the prospective expansion of the labour force, what are the output and employment growth rates, and the related pattern of structural change, required to prevent a worsening of underemployment and income distribution? Second, given Mexico's debt problems since the early 1980s, what is the ou...
Buoyant Jets Discharging Nonvertically Into a Uniform, Quiescent Ambient—A Finite-Difference Analysis and Turbulence Modeling

A differential approach for analysis of turbulent, axisymmetric, buoyant jets and plumes issuing nonvertically into a quiescent, uniform ambient is presented, in which the governing differential equations for conservation of mass, momentum, and energy, derived in a curvilinear, orthogonal coordinate system, are solved by a finite-difference method of the Dufort-Frankel type. This jet configuration is of interest with regard to the design of submerged, offshore outfalls from power plants. The analysis includes consideration of the transverse momentum equation as the jet follows a curved trajectory under the influence of buoyancy forces. The turbulent shear stress and heat flux terms in the governing equations are evaluated through a relatively simple turbulence model which accounts for the effect of buoyancy on the apparent turbulent viscosity through the gradient Richardson number. Predictions for buoyant jets discharging horizontally and at 45 deg to the horizontal are compared with recent experimental data and the results of other prediction methods.
Blind inversion in nonlinear space-variant imaging using Cauchy machine

A Cauchy Machine has been applied to solve nonlinear space-variant blind imaging problem with positivity constraints on the pixel-by-pixel basis. Nonlinearity parameters, de-mixing matrix and source vector are found at the minimum of the thermodynamics free energy H=U-T0S, where U is estimation error energy, T 0 is temperature and S is the entropy. Free energy represents dynamic balance of an open information system with constraints defined by data vector. Solution was found through Lagrange Constraint Neural Network algorithm for computing the unknown source vector, exhaustive search to find unknown nonlinearity parameters and Cauchy Machine for seeking de-mixing matrix at the global minimum of H for each pixel. We demonstrate the algorithm capability to recover images from the synthetic noise free nonlinear mixture of two images. Capability of the Cauchy Machine to find the global minimum of the golf hole type of landscape has hitherto never been demonstrated in higher dimensions with a much less computation complexity than an exhaustive search algorithm.
Building a Testis: Formation of Functional Testis Tissue after Transplantation of Isolated Porcine (Sus scrofa) Testis Cells

During mammalian development, morphogenesis of the testis requires the coordinated interplay of somatic cells to form seminiferous cords in which the primitive germ cells reside. These cords are the precursor of the functional male gonad and as such form the basis of male fertility. Cell migration during mammalian organogenesis and formation of complex tissues, such as the testis, are difficult to study in situ. Herein, we report extensive rearrangement of cells to regenerate complete functional testis tissue after implantation of isolated neonatal porcine testis cells under the skin of immunodeficient mice. Somatic cells and germ cells reorganized into structures that have remarkable morphologic and physiologic similarity to normal testis tissue, forming the endocrine and spermatogenic compartment of the testis. This unique in vivo system provides an accessible model for the study of testicular morphogenesis that could be especially useful in nonrodent species.
Zur Chemie der kondensierten Phosphate und Arsenate. III. Über die Herstellung und Eigenschaften von Meta - Arsenatophosphaten und die Konstitution des MADDRELLschen Salzes (NaPO3)x

Auf Grund von DEBYE- und Drehkristallaufnahmen und durch Bestimmung der spezifischen Gewichte und Molekularvolumina wird gezeigt, das aus den Schmelzen von Gemischen aus NaH2AsO4 und NaH2PO4 beim Tempern Kristalle der Zusammensetzung [Na(As,P)O3]x, also Metaarsenatophosphate, entstehen, die den gleichen Bau wie die Hochtemperaturform des Maddrellschen Salzes, der in Wasser unloslichen Modifikation des Natriummetaphosphates, haben. Fur das gegen Wasser sehr instabile Natriummetaarsenat wird ein ganz ahnlicher Bau sehr wahrscheinlich gemacht. Bei der Hydrolyse werden die Mischpolymerisate, wenn sie nicht mehr als 4 P-Atome auf 1 As-Atom und diese in ganzzahligen Atomverhaltnissen enthalten, in Orthoarsenat und jeweils ein ganz bestimmtes Polyphosphat aufgespalten, dessen Gliederzahl der pro As-Atom im Kristall enthaltenen P-Atome entspricht. Hieraus wird auf den Kettenbau der Anionen der Mischpolymerisate und des Maddrellschen Salzes in der Hochtemperaturform geschlossen. Ein zweiter Weg zur Herstellung von Tetraphosphaten wird angegeben. Aus Schmelzen mit mehr als 5 PO3-Resten auf 1 AsO3-Rest scheidet sich neben dem 1:4-Meta-Arsenatophosphat der Uberschus an Phosphor als Trimetaphosphat aus. Aus der 1:5-Schmelze entsteht als Nebenprodukt ein Metaphosphat bisher unbekannter Konstitution, das ein in Wasser schwer losliches, farbloses Silbersalz gibt.
Model calculation of gas-surface energy accommodation coefficients: The importance of multiple collisions and of trapping

A theoretical study of gas-surface energy transfer is presented based on a model in which a gas-surface collision is pictured as the collision between an atom and a harmonic oscillator. The gas-surface interaction potential is taken as a one-dimensional square well. The motion of gas and surface atoms is accounted for exactly by integrating over the respective velocity distributions. In the absence of trapping, i.e. with a purely repulsive potential, the energy accommodation coefficient (EAC) is independent of surface temperature Ts and gas temperature Tg as long as Ts ⪡ Tg or Ts ⪢ Tg. When Ts = Tg the EAC diverges unless multiple collisions are taken into account. With a non-zero attractive potential, the dependence of the EAC on Ts, Tg, gas atom mass and angle of incidence is dominated by the dependence of the trapping probability on those parameters. The general validity of these results is examined, and some assumptions frequently made in model studies of gas-surface energy transfer are discussed in light of these results.
Characterization of General Esterases from Susceptible and Parathion-Resistant Strains of the Greenbug (Homoptera: Aphididae)

J. Econ. Entomol. 87(6): 1430-1436 (1994) ABSTRACT A susceptible and two parathion-resistant strains of the greenbug, Schiza- phis graminum (Rondani), exhibit three different patterns of general esterase isozymes in native polyacrylamide electrophoresis gels. Characterization of general esterase activity using a-naphtholic esters as model substrates indicated that the three strains differed in isozyme composition. The type-I1 strain, which had the highest level of resistance, exhib- ited the highest levels of general esterase activity under all assay conditions, and the type-I strain had consistently higher levels than the susceptible strain. In all three strains, these esterases were more active toward a-naphtholic esters with side chains of six or fewer carbon atoms. a-Naphthyl propionate was the optimal substrate for both susceptible and type-I strains, and a-naphthyl butyrate for type 11. Over 90% of esterase activity was localized in the cytosolic fraction of type-I1 greenbugs. In susceptible and type-I green- bugs, the activity was distributed equally between the cytosolic and microsomal fractions. Differences in kinetic properties of the general esterases from the three strains also were evident, further indicating differences in isozyme composition. Although the three strains differed in properties of the general esterase activities, the differences do not provide sufficient discrimination to distinguish reliably among the three strains using single aphid activity measurements.
Longitudinal profiles of oxygen uptake during treadmill walking in able-bodied children: the locomotion energy and growth study.

Abstract The purpose of this study was to document age-related changes in walking V O 2 in able-bodied boys and girls. Beginning at age 6 and ending at age 10, 23 children (14 girls, 9 boys) performed six 5-min bouts of level treadmill walking at 0.67, 0.89, 1.12, 1.34, 1.56, and 1.79 m s −1 on an annual basis. Prior to data collection, subjects received 60 min of treadmill walking practice. During the last 2 min of each walking bout, a 2-min sample of expired air was collected in a meteorological balloon and analyzed to determine V O 2 . Averaged across age, interindividual variation in V O 2 ranged from 32 to 41%. Repeated-measures analysis of variance demonstrated a speed by age interaction for V O 2 , such that mean V O 2 rose ( P ≤0.05) across the five fastest speeds for 6-, 7-, 8-, and 10-year olds and increased over the entire speed range for 9-year olds. For all speeds, V O 2 decreased yearly from the ages of 6 to 8. When averaged across speeds, V O 2 was 27% higher for 6-year olds compared with 10-year olds. From a clinical perspective, access to longitudinal measurements of walking V O 2 in able-bodied children should be helpful in interpreting gait energy use in children with movement disorders and evaluating treatment strategies designed to reduce the aerobic demand of locomotion in youth with impaired mobility.
Flower vases in hospitals as reservoirs of pathogens.

Abstract Flower vases on surgical wards and a burn unit in two Miami hospitals carried large numbers of potentially pathogenic bacteria in the water they contained. Bacterial counts reached 1×10 13 colony-forming units (C.F.U.) per ml. within 3 days of placing flowers in clean tap-water. Counts of gentamicin-resistant bacteria in flower vases found on surgical wards reached 8 million C.F.U. per ml. of flower water. Among the species identified were Pseudomonas œruginosa, Ps. cepacia, Ps. alcaligenes, Aeromonas hydrophila, Acinetobacter spp., Flavobacterium spp., Escherichia coli, Klebsiella ozœna, and Proteus mirabilis. Six of these species have previously been reported as causing hospital infections. These findings suggest that flowers should not be introduced into hospital areas occupied by susceptible or debilitated patients.
Solution to a Bistable Vibration Problem Using a Plain, Uncentralized Squeeze Film Damper Bearing

During service introduction of an uprated turbojet engine, which has a three-bearing rotor support system with an overhung turbine, several problems related to system vibration were encountered — cabin noise and high engine vibration levels. These problems led to a factory and field investigation which showed that the source of the problem was a nonlinear interaction between rotor and casing modes coupled through bearing clearance. This interaction led to a bistable vibration of the system. This paper documents the results of this investigation and demonstrates that the use of a plain, uncentralized, squeeze film damper to support the turbine rotor solves all vibration problems by reducing the turbine critical speed and separating it from the casing mode. Also included are effects of exhaust system weight on engine vibration and cabin noise levels.Copyright © 1982 by ASME
Compact high power mid-IR spectroscopic source based on difference frequency generation in PPLN

An all solid-state, fiber coupled spectroscopic source based on difference frequency generation (DFG) in periodically poled lithium niobate (PPLN) is reported that generates up to 0.7 mW continuous wave (cw), tunable mid-infrared power at 3.3 µm with a linewidth of < 60 MHz.
Treatment and Prophylaxis of Hematologic Malignancy in the Central Nervous System

Central nervous system (CNS) involvement is a serious, and frequently fatal, complication of acute leukemias and very aggressive lymphomas. In patients with no evidence of CNS involvement at the time of diagnosis, the decision to include CNS prophylaxis in the treatment regimen should be based on cytologic diagnosis and other risk factors. Patients with a risk of CNS relapse greater than 10% should receive CNS prophylaxis with high-dose systemic chemotherapy, intrathecal therapy, radiation, or a combination thereof. The most commonly used systemic and intrathecal chemotherapies are methotrexate and cytarabine. Liposomal cytarabine, which increases CNS bioavailability and decreases the number of lumbar punctures needed, is our preference for intrathecal therapy. We usually reserve radiation therapy for patients who may not tolerate other forms of CNS prophylaxis. Patients with evidence of CNS involvement, either at diagnosis or relapse, should be treated until CNS disease clearance or dose-limiting toxicity is reached. Recent studies suggest that autologous stem cell transplantation may offer longer survivals for patients with CNS involvement and should be considered for patients who can tolerate the procedure. The use of rituximab in CNS prophylaxis and treatment has not yet been clearly delineated, but initial reports indicate that this agent and others may soon be available as an effective and tolerable CNS-directed therapy for lymphomas.
Dynamic Complexation of Copper(I) Chloride by Carbene- Stabilized Disilicon

Reaction of N-heterocyclic-carbene (NHC)-stabilized disilicon (1) with CuCl gave a carbene-stabilized disilicon-copper(I) chloride complex (2). The nature of the structure and bonding in 2 has been investigated by crystallographic, spectroscopic, and computational methods. The dynamic complexation behavior of 2 was experimentally explored by variable-temperature NMR analysis.
FOXO3A directs a protective autophagy program in haematopoietic stem cells

Blood production is ensured by rare, self-renewing haematopoietic stem cells (HSCs). How HSCs accommodate the diverse cellular stresses associated with their life-long activity remains elusive. Here we identify autophagy as an essential mechanism protecting HSCs from metabolic stress. We show that mouse HSCs, in contrast to their short-lived myeloid progeny, robustly induce autophagy after ex vivo cytokine withdrawal and in vivo calorie restriction. We demonstrate that FOXO3A is critical to maintain a gene expression program that poises HSCs for rapid induction of autophagy upon starvation. Notably, we find that old HSCs retain an intact FOXO3A-driven pro-autophagy gene program, and that ongoing autophagy is needed to mitigate an energy crisis and allow their survival. Our results demonstrate that autophagy is essential for the life-long maintenance of the HSC compartment and for supporting an old, failing blood system.
Clinical pearls in dermatology.

At the 2001 Annual Conference of the American College of Physicians, a new teaching format to aid physician learning, Clinical Pearls, was introduced. Clinical Pearls is designed with the 3 qualities of physician-learners in mind. First, we physicians enjoy learning from cases. Second, we like concise, practical points that we can use in our practice. Finally, we take pleasure in problem solving.
Conception rates in dairy cows after timed-insemination and simultaneous treatment with gonadotrophin releasing hormone and/or prostaglandin F2 alpha

Abstract This study was designed to determine conception rates in dairy cows after timed-insemination and simultaneous treatment with gonadotrophin releasing hormone (GnRH) and/or prostaglandin F2 alpha (PGF2α). A total of 2352 cows was randomly assigned to six groups. Cows in Groups 1 to 5 were palpated per rectum to determine the presence of a corpus luteum (CL) on the ovary, and blood samples were obtained for the determination of plasma progesterone (P4) concentrations. Cows with a CL and P4 concentrations >1 ng/ml were treated (Day 0) with PGF2α (25 mg, i.m.) and were observed for estrus. Cows in estrus prior to 72 hours after treatment (Group 5, n = 106) were bred, but were not treated. Cows not observed in estrus by 72 hours were divided into four remaining groups, were bred between 72 and 80 hours and were assigned as follows: Cows in Group 1 (n = 203) were not treated; Cows in Group 2 (n = 200) were treated with GnRH (100 ug, i.m.); Cows in Group 3 (n = 201) were treated with PGF2α (25 mg, i.m.); and cows in Group 4 (n = 202) were treated with both GnRH and PGF2α. Cows in Group 6 (n = 1440) were not treated with PGF2α on Day 0 and were estrual cows that were bred on days when cows in Groups 1 to 5 were time-inseminated. The percentage of cows in all groups pregnant at 45 to 50 days after one insemination was compared using analysis of variance (P
Left ventricular mechanical dyssynchrony by phase analysis of gated single photon emission computed tomography in end-stage renal disease.

The presence and degree of left ventricular (LV) dyssynchrony in patients with end-stage renal disease (ESRD) has not been well studied. We hypothesized that these patients would be more likely to have mechanical dyssynchrony than a control cohort. The indexes of LV mechanical dyssynchrony were measured by automated analysis of gated single photon emission computed tomography myocardial perfusion imaging in 290 patients with ESRD and 109 control patients. Only patients with normal myocardial perfusion imaging findings and a narrow QRS duration were included. The following variables were derived: LV ejection fraction (EF), volume, mass, and 2 indexes of dyssynchrony, the standard deviation and bandwidth. The standard deviation and bandwidth were significantly greater in those with ESRD (23° ± 13° vs 15° ± 6° and 65° ± 40° vs 42° ± 14°, respectively, p 43° (p = 0.01). In conclusion, patients with ESRD had significantly more mechanical dyssynchrony than did the control group, even in absence of electrical dyssynchrony and abnormal LV perfusion or function.
Aqueous-phase adsorption of glycerol and propylene glycol onto activated carbon

Abstract Adsorption of reactant and product species can have a major effect on local pore concentrations in activated carbon-supported metal catalysts. Individual and combined adsorption of glycerol (GO) and propylene glycol (PG) onto activated carbon in aqueous solution is reported here at concentration ranges of 0.05–2.0 M and temperatures from 25 °C to 160 °C. Langmuir and Freundlich isotherms are used to model the single component data, with the Langmuir model best describing results below 0.75 M. The extended Langmuir model has been used to model the competitive adsorption system – model parameters determined from single component experiments accurately predict two component adsorption data over the temperature and concentration ranges studied. Propylene glycol adsorbs more strongly than GO onto the activated carbon supports studied, and also adsorbs to a somewhat greater extent compared to GO. This is attributed to the greater organic character of PG, which favors its selective adsorption onto the support material.
Centerline-based colon segmentation for CT colonography

We have developed a fully automated algorithm for colon segmentation, centerline-based segmentation (CBS), which is faster than any of the previously presented segmentation algorithms, but also has high sensitivity as well as high specificity. The algorithm first thresholds a set of unprocessed CT slices. Outer air is removed, after which a bounding box is computed. A centerline is computed for all remaining regions in the thresholded volume, disregarding segments related to extracolonic structures. Centerline segments are connected, after which the anatomy-based removal of segments representing extracolonic structures occurs. Segments related to the remaining centerline are locally region grown, and the colonic wall is found by dilation. Shape-based interpolation provides an isotropic mask. For 38 CT datasets, CBS was compared with the knowledge-guided segmentation (KGS) algorithm for sensitivity and specificity. With use of a 1.5 GHz AMD Athlon-based PC, the average computation time for the segmentation was 14.8 s. The sensitivity was, on average, 96%, and the specificity was 99%. A total of 21% of the voxels segmented by KGS, of which 96% represented extracolonic structures and 4% represented the colon, were removed.
Orbital forces and chemical bonding in density-functional theory: Application to first-row dimers

The local-density-functional description of chemical bonding in first-row homonuclear dimers is analyzed in terms of both static and dynamic orbital forces. The dynamic orbital force of the i-italicth molecular orbital is equal to the negative of the derivative of the one-electron energy epsilon-c/sub i-italic/ with respect to the p-italicth nuclear coordinate, i.e., -partialepsilon-c/sub i-italic//partialX/sub p/. The static orbital force is also equal to a derivative of the one-electron energy, but the differentiation is carried out with the orbital held fixed, i.e., (-partialepsilon-c/sub i-italic//partialX/sub p/)psi. It is shown that the static force is the orbital's contribution to the total Hellmann-Feynman force, whereas the dynamic force describes the change in the total force due to change in the orbital's occupation number. The chemical bond force in the first-row dimers is observed to be a delicate balance between bonding and antibonding orbital forces. Most of the bond force comes from the 2sigma/sub g-italic/ orbital and to a lesser extent from the 1..pi../sub u-italic/ state. The polarization of the core orbitals in N/sub 2/, O/sub 2/, and F/sub 2/ is found to originate indirectly through their interaction with the 3sigma/sub g-italic/ orbital. The dynamic orbital force gives accurate predictions about the change of equilibriummore » bond distances accompanying electronic ionization and excitation. The formalism and results are related to earlier Hartree-Fock studies.« less
Radiation damage in l-valine at liquid helium temperature

One of the most fundamental limitations to resolution in the electron microscopy of organic materials is the structural damage caused by the incident radiation. While the primary inelastic interactions between the electrons and the specimen molecules cannot be stopped, it has been hoped that the use of very low temperatures would ‘freeze’ molecular fragments in place to allow extended microscopy of minimally damaged structures. Knapek and Dubochet1 have reported that the rate of damage is much less (30–300 times) when diffraction patterns of organic materials are observed in an electron microscope with a superconducting objective lens, in which the specimen is held at 4.2 K. Previous workers had not seen such an effect when using liquid helium cooled stages, and it was suggested1 that this was mostly due to insufficiently low temperature. A microscope with a superconducting objective lens, which was constructed at Oak Ridge National Laboratory2, has been installed recently at Duke University. We selected l-valine as a test material because it has been so extensively examined in the past. Knapek and Dubochet1 reported that l-valine crystals at 4.2 K could tolerate an electron dose 67 times greater than at room temperature and Dietrich et al.3, using the same microscope, reported a tolerance 87 times greater; we report here that it is only 4 to 6 times greater. We have tested effects of temperature and of the specimen substrate, both suggested as important components in the limitation of radiation damage, and we find no further improvement. The results of Knapek and Dubochet and Dietrich et al. therefore remain unconfirmed, and the mechanism and extent of protection from radiation-induced damage at low temperatures must remain under study.
Disbelievers in evolution.

In their Policy Forum “Public acceptance of evolution” (11 Aug., p. [765][1]), J. Miller, E. Scott, and S. Okamoto show that Americans are less likely to accept evolution than citizens of other industrial nations, and that U.S. attitudes are strongly tied to fundamentalist religious beliefs.
Genetic analyses of gene function and pathogenesis of murine cytomegalovirus by transposon-mediated mutagenesis

Murine cytomegalovirus (MCMV) has a linear genome of 230 kb and encodes more than 170 genes, many of which have not been extensively studied for their functions in pathogenesis in vivo. A Tn3-based transposon was constructed and used to generate MCMV mutants by disrupting viral gene targets. The functions of the mutated genes were investigated by studying the viral mutants in cultured cells and in immunocompetent Balb/c and immunodeficient SCID mice. A pool of MCMV mutants that contained the transposon sequence randomly inserted at the viral genome was generated. Studies of several mutants (e.g. a viral mutant with the transposon inserted at open reading frame m09) in cultured cells and in mice indicate that the presence of the transposon sequence per se in the viral genome does not significantly affect viral growth in vitro and in vivo. Moreover, the genome structures of the viral mutants, including the transposon insertion regions, were stable during replication in cultured cells and in animals. Several viral mutants (e.g. a viral mutant with the transposon at M27) that are attenuated in growth and virulence in animals were identified. These results suggest that the genes mutated in these viral mutants may be important for viral virulence and pathogenesis. The Tn3-based system may be a useful tool for the systematic construction of CMV mutants and for studies of CMV gene functions in viral replication in vitro and in pathogenesis in vivo.
A fourth-order approximate projection method for the incompressible Navier-Stokes equations on locally-refined periodic domains

In this follow-up of our previous work [30], the author proposes a high-order semi-implicit method for numerically solving the incompressible Navier-Stokes equations on locally-refined periodic domains. Fourth-order finite-volume stencils are employed for spatially discretizing various operators in the context of structured adaptive mesh refinement (AMR). Time integration adopts a fourth-order, semi-implicit, additive Runge-Kutta method to treat the non-stiff convection term explicitly and the stiff diffusion term implicitly. The divergence-free condition is fulfilled by an approximate projection operator. Altogether, these components yield a simple algorithm for simulating incompressible viscous flows on periodic domains with fourth-order accuracies both in time and in space. Results of numerical tests show that the proposed method is superior to previous second-order methods in terms of accuracy and efficiency. A major contribution of this work is the analysis of a fourth-order approximate projection operator.
Stability of the Marchenko inversion

The stability of the Marchenko inversion in one-dimensional nonrelativistic quantum mechanics is studied. First, two bounds on the integral of the potential difference are given in terms of the integral of the difference in the scattering matrix. Second, a pointwise bound on the potential difference is obtained. Finally, the estimates are refined for the case of two scattering matrices coinciding on the finite energy interval k in (0,N).
A generative semi-supervised model for multi-view learning when some views are label-free

We consider multi-view classification for the challenging scenario where, for some views, there are no labeled training examples. Several discriminative approaches have been recently proposed for special instances of this problem. Here, alternatively, we propose a generative semi-supervised mixture model across all views which, via marginalization, flexibly performs exact class inference, given any subset of available views. The proposed model is an extension of semi-supervised mixtures to a multi-view setting, as well as a semi-supervised extension of mixtures of factors analyzers (MFA)[1]. A novel EM algorithm with a computationally efficient E-step is derived for learning our multi-view model. Specialization of this formulation to the standard MFA problem also gives a reduced complexity E-step, compared to the original EM algorithm proposed for MFA. Our multi-view method is experimentally demonstrated on digit recognition using audio and lip video views, achieving competitive results with alternative, discriminative approaches.
Mechanisms of Substrate Degradation by Energy-Dependent Proteases

Energy-dependent proteases of the AAA+ family catalyze the highly specific protein degradation involved in cellular protein quality control and the regulation of numerous vital processes, yet the detailed mechanisms coupling ATP hydrolysis with mechanical substrate unfolding and translocation remain poorly understood.Our cryo-EM structural studies of the eukaryotic 26S proteasome show that its heterohexameric AAA+ ATPase ring adopts a conformation with pronounced spiral-staircase arrangement of subunits in the absence of substrate, but transitions into a translocation-competent conformation upon substrate engagement. This substrate-engaged ring conformation is characterized by uniform interfaces between the six ATPase subunit, a widened central channel coaxially aligned with the peptidase, and a rearranged, more planar spiral orientation of ATPase subunits that suggests a highly coordinated rapid progression of ATP-hydrolysis events around the ring.This coordinated ATP hydrolysis mechanism is further supported by our optical tweezers single-molecule studies of the related bacterial protease ClpXP and may be a general feature of AAA+ translocases. ClpXP translocates substrate polypeptides in steps with constant frequency but variable length, depending on the number of ATP-hydrolyzing subunits.