cssi/SciSciGPT-SciSciNet huggingface dataset:
Symptomatic and Asymptomatic Host Range of Fusarium virguliforme, the Causal Agent of Soybean Sudden Death Syndrome

Sudden death syndrome, caused by Fusarium virguliforme, is an important disease of soybean in the United States. Fifteen species of crops, weeds, or prairie plants were evaluated for their potential as hosts of F. virguliforme. Root and foliar symptoms and plant biomass were assessed following greenhouse inoculation studies. Root colonization of F. virguliforme was determined with isolations and with polymerase chain reaction assays. Soybean, alfalfa, pinto and navy bean, white and red clover, pea, and Canadian milk vetch developed root necrosis. Soybean, alfalfa, and red clover also developed foliar symptoms following inoculation. Sugar beet and canola did not develop symptoms but had significant reductions in biomass, suggesting that they are also hosts of F. virguliforme. Corn, wheat, ryegrass, pigweed, and lambsquarters did not develop symptoms. However, these species appeared to be asymptomatic hosts because quantities of pathogen DNA detected in inoculated roots were similar to quantities detected in inoculated soybean roots. These results suggest that the number and diversity of hosts for F. virguliforme are greater than previously reported. The likely broad host range limits the efficacy of crop rotation and indicates that crops other than soybean can be damaged by F. virguliforme and maintain or increase inoculum in soil.
Monte Carlo Simulation of Shear Capacity of URM Walls Retrofitted by Polyurea Reinforced GFRP Grids

A model proposed in the literature for the evaluation of the in-plane shear capacity of unstrengthened and strengthened concrete and clay brick unreinforced masonry (URM) walls was modified and calibrated following the results from an experimental research program. The tested walls were strengthened with grids made from glass fiber-reinforced polymer (GFRP) embedded within a rapid-setting sprayed polyurea. Various GFRP grid reinforced polyurea layouts were investigated, and consisted of strips oriented in either the vertical or horizontal direction and installed on one or both faces. The prediction models proposed in this paper were subsequently evaluated using a probabilistic Monte Carlo simulation (MCS) by considering the uncertainty and variability of the independent variables, which were assumed to follow a truncated normal distribution. Corroborated by the MCS, test results clearly show that the failure modes of the strengthened URM walls were affected by the strengthening scheme. Experimental and simulation results are presented and discussed in this paper.
Characteristics of College Students Enrolled in an Alternative Health/Complementary and Alternative Medicine Course: A Cross-Sectional Comparison

Context The rising prevalence of chronic disease in the United States signifies a need for innovative health education strategies. One approach would be to integrate holistically oriented alternative health content into university health education curricula. This would capitalize on growing consumer interest in alternative health practices and on the observed relationship between the use of alternative health practices and conventional preventive health behaviors. Objective The aim of this study was to explore the potential value of alternative health curricula. The study was conducted to obtain information on demographics, attitudes, and behaviors of students enrolled in a holistic health education course. Design A cross-sectional survey design was employed. Setting Data was collected at a public university that offers a comprehensive undergraduate holistic health curriculum. Participants Participants were undergraduate students fulfilling general education requirements. Methods A convenience sample of three self-selected groups was surveyed: a holistic health education course, a conventional health education course, and a human sexuality course. Outcome Measures Outcomes included use of alternative health/complementary and alternative medicine practices, perceived effects of courses on health behaviors, intentions for future employment in a health field, and identification with holistic postmodern cultural values. Results Holistic health students were significantly more likely to employ alternative health practices and to report identification with holistic cultural values compared with the other two groups. Both holistic and conventional health education students were significantly more likely to report perceived positive effects of courses on health behaviors and intended future employment in a health profession. Implications for health promotion and workforce development are considered. Conclusion Findings suggest potential benefits of including holistic health content in university health education curricula. Replication with a larger, representative student sample would be a logical next step.
Ultrasensitive magnetic biosensor for homogeneous immunoassay

Abstract A technique is described for specific, sensitive, quantitative, and rapid detection of biological targets by using superparamagnetic nanoparticles and a “microscope” based on a high-transition temperature dc superconducting quantum interference device (SQUID). In this technique, a mylar film to which the targets have been bound is placed on the microscope. The film, at room temperature and atmospheric pressure, is typically 40 μm from the SQUID, which is at 77 K in a vacuum. A suspension of magnetic nanoparticles carrying antibodies directed against the target is added to the mixture in the well, and 1-s pulses of magnetic field are applied parallel to the SQUID. In the presence of this aligning field the nanoparticles develop a net magnetization, which relaxes when the field is turned off. Unbound nanoparticles relax rapidly by Brownian rotation and contribute no measurable signal. Nanoparticles that are bound to the target on the film are immobilized and undergo Neel relaxation, producing a slowly decaying magnetic flux, which is detected by the SQUID. The ability to distinguish between bound and unbound labels allows one to run homogeneous assays, which do not require separation and removal of unbound magnetic particles. The technique has been demonstrated with a model system of liposomes carrying the FLAG epitope. The SQUID microscope requires no more than (5 ± 2) × 104 magnetic nanoparticles to register a reproducible signal.
The expected linearity of a simple equivalence algorithm

Abstract The average time needed to form unions of disjoint equivalence classes, using an algorithm suggested by Aho, Hopcroft, and Ullman, is shown to be linear in the total number of elements, thereby establishing a conjecture of Yao. The analytic methods used to prove this result are of interest in themselves, as they are based on extensions of Stepanov's approach to the study of random graphs. Several refinements of Yao's analyses of related algorithms are also presented.
Microplasmas and applications

Atmospheric-pressure, non-equilibrium plasmas are susceptible to instabilities and, in particular, to arcing (glow-to-arc transition). Spatially confining the plasma to dimensions of 1 mm or less is a promising approach to the generation and maintenance of stable, glow discharges at atmospheric-pressure. Often referred to as microdischarges or microplasmas, these weakly-ionized discharges represent a new and fascinating realm of plasma science, where issues such as the possible breakdown of 'pd scaling' and the role of boundary-dominated phenomena come to the fore. Microplasmas are generated under conditions that promote the efficient production of transient molecular species such as the rare gas excimers, which generally are formed by three-body collisions. Pulsed excitation on a sub-microsecond time scale results in microplasmas with significant shifts in both the temperatures and energy distribution functions associated with the ions and electrons. This allows for the selective production of chemically reactive species and opens the door to a wide range of new applications of microplasmas. The implementation of semiconductor and microelectronics and MEMs microfabrication techniques has resulted in the realization of microplasma arrays as large as 250,000 devices. Fabricated in silicon or ceramics with characteristic device dimensions as small as 10 µm and at packing densities up to 104 cm−2, these arrays offer optical and electrical characteristics well suited for applications in medical diagnostics, displays and environmental sensing. Several microplasma device structures, including their fundamental properties and selected applications, will be discussed.
CELL-MEDIATED CYTOTOXIC MECHANISMS

There are two competing, but probably really complementary, models for the mechanism of cell-mediated cytotoxicity. One depends upon contact-mediated transmembrane signaling, and the other on the exocytosis of toxic materials by the killer cell. There is exciting news on both fronts. Transmembrane signaling has been shown to involve the surface molecule Fas/APO-1 on targets and its ligand on cytotoxic T cells. The Fas ligand has been cloned, and is a member of the tumor necrosis factor family. The major cytolytic molecule in the exocytosis pathway is perforin; perforin knock-out mice have been produced, and they display many intriguing abnormalities. It has been a bumper year for cytotoxicologists.
THE COLLECTION AND LOSS OF RADIOACTIVE IODINE COMPARED WITH THE ANATOMIC CHANGES INDUCED IN THE THYROID OF THE CHICK BY THE INJECTION OF THYROTROPIC HORMONE1

THE MODE of action of thyrotropic hormone has been the subject of intensive study. This is not surprising in view of the fact that of the various active principles of the anterior hypophysis the thyrotropic fraction is one whose anatomic and physiologic effects are most readily adaptable to quantitative observations. Furthermore much interest in the effects of thyrotropic hormone arises from the fact that its injection is a practical means of producing experimentally in thelaboratory animal a goiter which is both hyperplastic and hyperfunctioning (Lambie, 1939). Marine (1915) was the first to study the marked capacity of the thyroid gland to collect exogenous iodine. Both in vivo experiments (Marine, 1915) and in vitro perfusion studies (Marine and Feiss, 1915) disclosed that the capacity to collect iodine increased with the degree of hyperplasia of the gland. Marine and Rogoff (1916a and b) demonstrated that the rate of collection of an injected dose of iodine was greatest during the first ten minutes.
Half-time-based reflectivity tomography and its application to thermoacoustic tomography

Thermoacoustic tomography (TAT) is an emerging imaging technique with great potential for a wide range of biomedical imaging applications. In this work, we propose and investigate reconstruction approaches for TAT that are based on the half-time reflectivity tomography paradigm. We demonstrate that half-time reconstruction approaches can produce images in TAT that possess better statistical properties than images produced by use of conventional reconstruction approaches.
Quasi-equilibrium pharmacokinetic model for drugs exhibiting target-mediated drug disposition.

The aim of this study is to derive and evaluate an equilibrium model of a previously developed general pharmacokinetic model for drugs exhibiting target-mediated drug disposition (TMDD). A quasi-equilibrium solution to the system of ordinary differential equations that describe the kinetics of TMDD was obtained. Computer simulations of the equilibrium model were carried out to generate plasma concentration-time profiles resulting from a large range of intravenous bolus doses. Additionally, the final model was fitted to previously published pharmacokinetic profiles of leukemia inhibitory factor (LIF), a cytokine that seems to exhibit TMDD, following intravenous administration of 12.5, 25, 100, 250, 500, or 750 μg/kg in sheep. Simulations show that pharmacokinetic profiles display steeper distribution phases for lower doses and similar terminal disposition phases, but with slight underestimation at early time points as theoretically expected. The final model well-described LIF pharmacokinetics, and the final parameters, which were estimated with relatively good precision, were in good agreement with literature values. An equilibrium model of TMDD is developed that recapitulates the essential features of the full general model and eliminates the need for estimating drug-binding microconstants that are often difficult or impossible to identify from typical in vivo pharmacokinetic data.
The evolving approval plan: how academic librarians evaluate services for vendor selection and performance

A survey of 291 academic librarians addressed the question of how libraries choose approval plan vendors, specifically how much emphasis is placed on various approval plan services and product features in choosing between competing approval plan vendors and how vendor performance is rated in those areas. Traditional services, including expertise in managing approval plans, e.g., profiling, and acquisitions services, customer service, and discount rate, along with corporate reputation and business practices, retained their core status. Electronic financial transactions was found to be very important to the libraries already using these services. Outsourcing services, e.g., cataloging or physical processing, with approval plan vendors, although newer, appear established and of considerable interest to some segments. Vendor performance was rated highest in corporate reputation, approval plan management, and in electronic financial transactions. Libraries with approval budgets under $100,000 expressed a degre...
Using the landmark method for creating prediction models in large datasets derived from electronic health records

With the integration of electronic health records (EHRs), health data has become easily accessible and abounded. The EHR has the potential to provide important healthcare information to researchers by creating study cohorts. However, accessing this information comes with three major issues: 1) Predictor variables often change over time, 2) Patients have various lengths of follow up within the EHR, and 3) the size of the EHR data can be computationally challenging. Landmark analyses provide a perfect complement to EHR data and help to alleviate these three issues. We present two examples that utilize patient birthdays as landmark times for creating dynamic datasets for predicting clinical outcomes. The use of landmark times help to solve these three issues by incorporating information that changes over time, by creating unbiased reference points that are not related to a patient’s exposure within the EHR, and reducing the size of a dataset compared to true time-varying analysis. These techniques are shown using two example cohort studies from the Cleveland Clinic that utilized 4.5 million and 17,787 unique patients, respectively.
Designing readable scrolling displays

Abstract This report focuses on a form of scrolling display in which the message moves horizontally along a single-line display panel. Recommendations are given for the optimal scrolling mode, window width and display rate. The properties that enhance alphanumeric legibility and the techniques that maximize the effectiveness of a scrolling message are also discussed.
Testicular and Paratesticular Pathology in Children: a 12-Year Histopathological Review

Our institution is the principal pediatric surgical referral center for a population of 1.6 million. The objective of this study was to determine the spectrum and incidence of pediatric testicular and paratesticular pathology in this population. Pathology results of all testicular and paratesticular specimens between August 1995 to September 2007 were analyzed. Clinical details were retrieved retrospectively from the computerized database, recording age, mode of presentation, laterality, and associated inguinoscrotal pathology. Over 12 years 2 months, 474 patients (502 specimens) were identified. Testicular and paratesticular pathology was most frequent in patients aged 1–2 years (11%) and 11–12 years (10.5%). In all, 442 patients had non-neoplastic pathology, with 60.4% presenting acutely. The most common non-neoplastic pathologies were hydatid of Morgagni (42.6%) and “vanishing testis” (14.3%). Vanishing and atrophic testes were frequently explored between 1 and 2 years of age, with a left predominance. Most atrophic testes were undescended (54.8%). Testicular torsion occurred in 11.2%, with bimodal peak ages of <1 year and 13–14 years. Interestingly, testicular torsion also occurred more on the left side (68%). A total of 32 patients had neoplasms. Of 27 patients with testicular neoplasms, 55.6% were malignant (29.6% primary and 26% secondary), the principal primary malignancy was yolk sac tumor; the most common benign neoplasms were epidermoid cysts and teratomas. Five patients had paratesticular neoplasms, with rhabdomyosarcoma in 80%. The variety of scrotal and testicular pathology in children is considerable, with acute pathologic conditions comprising the bulk in the older (7–15 years) children, whereas impalpable testes and neoplasms comprise most of the lesions in infants. Interestingly testicular torsion, vanishing testes, and atrophic testes occur mainly on the left side. Benign testicular neoplasms occur more frequently than primary malignancies.
STOP-LIGHT COMPLIANCE BY CYCLISTS: AN INFORMAL LOOK

To gain some further insight as to the degree of mandated (New York State, 1984) cyclists' observance of stop-lights, noted in Trinkaus' (1984) study of motor vehicle compliance with such signals, the research design was replicated one year later by observing bicycles rather than motor vehicles. The same urban traffic intersection, through which flowed four lanes of east-west and four lanes of north-south traffic, was viewed. Similarly, a total of 45 1-hr. citings of convenience were made of the north-south movement, equally divided among Tuesday, Wednesday, and Thursday, during the summer months from 1000 to 1500 hours. The timing of the traffic signal was identical: 45 sec. "go" (green), 4 sec. "caution" (yellow), and 41 sec. "stop" (red). The definition of passing the stop-light was the same: entering into and continuing through the intersection in the face of a red signal. Bicycle traffic averaged approximately 137 machines per hour, of which about 61 confronted a red-signal situation. Of these, approximately 19 went through, 41 stopped seemingly only because the pattern of vehicle cross-traffic did not permit passage, while 1 halted apparently simply because the traffic signal was red. Also, 1-hr. viewings were made at six other large intersections in other parts of the area, through which flowed approximately 140 bicycles per hour per intersection. At four of the six, no cyclist, called upon to stop when confronted with a safe passage through the intersection, did so. At the other two a total of three cyclists stopped when they could have safely proceeded. The results imply support for Trinkaus' earlier suggestion that generally cyclists disregard stop signals. It is interesting to note, however, that about half of those running a red light sounded a whistle as they did so. The practice may well stem from advice on avoiding accidents suggested by leaders in the field, such as the Editors of Bike World ( 1976).
Role of Tai Chi in the Treatment of Rheumatologic Diseases

Rheumatologic diseases (e.g., fibromyalgia, osteoarthritis, and rheumatoid arthritis) consist of a complex interplay between biologic and psychological aspects, resulting in therapeutically challenging chronic conditions to control. Encouraging evidence suggests that Tai Chi, a multi-component Chinese mind–body exercise, has multiple benefits for patients with a variety of chronic disorders, particularly those with musculoskeletal conditions. Thus, Tai Chi may modulate complex factors and improve health outcomes in patients with chronic rheumatologic conditions. As a form of physical exercise, Tai Chi enhances cardiovascular fitness, muscular strength, balance, and physical function. It also appears to be associated with reduced stress, anxiety, and depression, as well as improved quality of life. Thus, Tai Chi can be safely recommended to patients with fibromyalgia, osteoarthritis, and rheumatoid arthritis as a complementary and alternative medical approach to improve patient well-being. This review highlights the current body of knowledge about the role of this ancient Chinese mind–body medicine as an effective treatment of rheumatologic diseases to better inform clinical decision-making for our patients.
Adriamycin and metabolites: separation by high-pressure liquid chromatography and quantitation by radioimmunoassay.

Abstract High-pressure liquid chromatography (HPLC) is used to separate adriamycin and the metabolites, adriamycinol, and adriamycin aglycone(s) found in the urine of patients treated with the drug. The concentrations of the isolated compounds are determined by radioimmunoassay (RIA). Their excretion rates decrease with time and their relative molar ratios vary in collections made at different times and from different individuals. This combined HPLC-RIA system offers an efficient and sensitive procedure for separation and estimation of these compounds that is not subject to interference from nonrelated endogenous materials which may affect results obtained with other methods.
Distinguishing native conformations of proteins from decoys with an effective free energy estimator based on the OPLS all-atom force field and the Surface Generalized Born solvent model.

Protein decoy data sets provide a benchmark for testing scoring functions designed for fold recognition and protein homology modeling problems. It is commonly believed that statistical potentials based on reduced atomic models are better able to discriminate native-like from misfolded decoys than scoring functions based on more detailed molecular mechanics models. Recent benchmark tests on small data sets, however, suggest otherwise. In this work, we report the results of extensive decoy detection tests using an effective free energy function based on the OPLS all-atom (OPLS-AA) force field and the Surface Generalized Born (SGB) model for the solvent electrostatic effects. The OPLS-AA/SGB effective free energy is used as a scoring function to detect native protein folds among a total of 48,832 decoys for 32 different proteins from Park and Levitt's 4-state-reduced, Levitt's local-minima, Baker's ROSETTA all-atom, and Skolnick's decoy sets. Solvent electrostatic effects are included through the Surface Generalized Born (SGB) model. All structures are locally minimized without restraints. From an analysis of the individual energy components of the OPLS-AA/SGB energy function for the native and the best-ranked decoy, it is determined that a balance of the terms of the potential is responsible for the minimized energies that most successfully distinguish the native from the misfolded conformations. Different combinations of individual energy terms provide less discrimination than the total energy. The results are consistent with observations that all-atom molecular potentials coupled with intermediate level solvent dielectric models are competitive with knowledge-based potentials for decoy detection and protein modeling problems such as fold recognition and homology modeling.
Regulation of cotton photosynthesis during moderate chilling

Abstract This study was initiated to determine the effect of long-term, moderate chilling at moderate light intensity on cotton (Gossypium hirsutum cv. Coker 312) leaf net photosynthesis (A). Upon exposure of warm-grown plants to 15°C and a photosynthetic photon flux density of ∼ 500 μmol m−2s−1, A declined 40% in 2 days and then an additional 20% from days 2 to 8. A parallel decline occurred in A measured at saturating CO2 and 28°C. Maintaining the roots at 27°C had no effect on the decline in A. The initial, 40% reduction in A was associated with an 88% reduction in stomatal conductance (gs), a 33% reduction in internal CO2 concentration (Ci), and a 29% reduction in the ratio of the variable to maximum chlorophyll fluorescence ( Fv Fm ), but the in vivo capacities of ribulose 1,5-bisphosphate carboxylase (Rubisco) and stromal fructose 1,6-bisphosphatase remained high, suggesting that the initial decline in A was primarily a photoinhibitory response coupled with some restriction by gs. From days 2 to 8, gs and Fv Fm remained constant, Ci rose gradually, and the inhibition of A by ambient O2 decreased from 25% to 4% implicating an increasing phosphate limitation to A. We hypothesized that this putative increase in phosphate limitation was the result of a slowing of sucrose and starch synthesis and not increased phosphate sequestration since the total pool of leaf hexose phosphate rose only 11% from day 1, starch accumulation during the photoperiod declined, and the extractable activity of sucrose phosphate synthase on day 8 was 60% of pre-chilling values. After the plants were returned to warm conditions, a 1-day lag in the recovery of A occurred that was associated with a decrease of in vivo Rubisco capacity, some photoinhibition, and a low gs.
The protein state of matter

Three ways are generally used to visualize proteins: (1) a static model in which the atomic positions are defined, (2) a dynamic model taking into account fluctuations, and (3) a reactive model that reflects the internal and external electric fields of the molecule. The properties of chromophoric prosthetic groups can be probed by optical spectroscopy, and when high resolution techniques are used, the results reveal information about the local electric fields in proteins, as influenced and determined by atomic positions and dynamics.
Influence of Sensor Substrate Geometry on the Sensitivity of MEMS Micro-Extensometers

In order to determine the influence of the silicon chip substrate on measurement fidelity in a silicon MEMS micro-extensometer, finite element modeling of strain transfer efficiency from a steel beam through a bond layer and silicon chip is investigated over a range of chip and steel beam geometries under both axial and pure bending load conditions. The finite element model results are verified against experimental data. An analytical model that incorporates both influence of the bonded substrate on the effective load and shear-lag phenomenon in the bond is developed and is shown to compare favorably to the finite element model over a wide range of chip and beam geometries. Based on these results, a partially-trenched silicon chip is also investigated as an alternate means of locally enhancing the strain transfer to the micro-extensometer without compromising the ability of the substrate to act as part of the encapsulation of moving elements of the micro-extensometer from the environment. The partially-trenched substrate in bending is experimentally shown to generate strains that are 118% of the strain applied to the substrate—a 23% percent improvement over the equivalent unpatterned substrate geometry.Copyright © 2005 by ASME
A physiologically based model of creatine kinase-MB release in reperfusion of acute myocardial infarction

To gain insight into the altered kinetics of creatine kinase-MB (CK-MB) release after reperfusion, a physiologically based model with first-order CK-MB appearance and disappearance functions was postulated. This biexponential model is based on the assumption that reperfusion reestablishes nutritive blood flow, providing direct access of interstitial CK-MB to the bloodstream. This is in contrast to persistent coronary artery occlusion, in which no direct access to nutritive flow is present. The accuracy of this model was examined in 8 dogs reperfused after 2 hours of coronary artery occlusion. The fit to observed values was excellent, with a mean r2 of 0.97 ± 0.05. In agreement with the biexponential model, the initial increase in CK-MB activity was abrupt and rapid. The same degree of accuracy was found in 21 patients with angiographic evidence of reperfusion after thrombolytic therapy (mean r2 0.97 ± 0.02). The appearance characteristics were similar to the animal model, with an abrupt and rapid increase in CK-MB activity. When compared with 5 patients with persistent occlusion, ka, the rate constant of the appearance function, clearly distinguished patients with reperfusion (chi-square = 20.6, p < 0.0001), whereas considerable overlap was present in the time to peak CK-MB (time to peak <12 hours, chi-square = 3.6, difference not significant). Alterations of CK-MB release in reperfusion can be accurately modeled with the biexponential model. The characteristics of this model suggest that early identification of reperfusion by serial CK-MB assay is possible.
The Fading affect bias: But what the hell is it for?

SUMMARY This article reviews research examining the fading affect bias (FAB): The finding that the intensity of affect associated with negative autobiographical memories fades faster than affect associated with positive autobiographical memories. The FAB is a robust effect in autobiographical memory that has been replicated using a variety of methods and populations. The FAB is linked to both cognitive and social processes that support a positive view of the self. Accordingly, we speculate that one function of the FAB may be to induce individuals to be positive and action-oriented so that they may better face and master life challenges. Copyright # 2009 John Wiley & Sons, Ltd. Baddeley (1988) challenged researchers in memory and cognition to explain any given phenomenon by answering a simple question: What the hell is for? The present article poses this question in relation to the fading affect bias (FAB). The FAB shows that the emotion associated with negative event memories generally fades faster than the emotion associated with positive event memories. This phenomenon has been well documented in several studies over the years, receiving the most intense scrutiny in the last decade. To better understand the possible functions of the FAB, this articlewill first review some of the classic perspectives on memory and emotion. Next, the article will provide a review of some the relevant research documenting this phenomenon, including research that describes factors that both strengthen and weaken the FAB. Finally, this article will consider the adaptive value of changes in the emotions that accompany autobiographical memories.
Myocardial distribution of coronary blood flow in the isolated supported heart preparation

The regional distribution of myocardial blood flow was studied by use of radioactive microspheres (15 micro-meters [mum]) under control conditions and during an intracoronary infusion of norepinephrine (2mug/min). In control experiments endocardial blood flow was generally greater than epicardial flow; during administration of norepinephrine the endocardium received significantly less blood flow. It is proposed that normally the endocardium is well perfused, but under conditions of stress, eg, norepinephrine infusion in the presence of a constant coronary blood flow, decreased endocardial blood flow results.
A structural superfamily of growth factors containing a cystine knot motif.

Neil Q. McDonald and Wayne A. Hendrickson Department of Biochemistry and Molecular Biophysics and Howard Hughes Medical Institute College of Physicians and Surgeons of Columbia University New York, New York 10032 The three-dimensional structures of proteins can provide important insights, sometimes unexpectedly, into the evo- lutionary relationships of proteins. Proteins may evolve from a common ancestor to the point at which they no longer share any significant overall sequence similarity (less than 20% identity), but their evolutionary relatedness may still be evident from a structural comparison. This is because those few invariant or conservatively replaced amino acid residues that are critical for the preservation of the three-dimensional structure can be identified from structural information. Locating such weaksignalsof relat- edness by sequence comparisons alone requires large numbers of sequences, whereas two related three- dimensional structures can be expected to show a good superposition of these invariant residues in topologically equivalent positions, despite great sequence divergence elsewhere. Polypeptide growth factors, a diverse group of regula- tory agents that control cell survival, proliferation, and dif- ferentiation, provide a good illustration of this phenome- non (Table 1). Nerve growth factor (NGF), transforming growth factor 82 (TGFj32), and platelet-derived growth fac- tor BB (PDGF-BB) have been found to adopt similar pro- tomeric structures that contain a motif we shall refer to as the cystine knot. These growth factors contain this motif and aconserved b-strand structure, arguing that they form a structural superfamily. The evolutionary and functional implications that arise from this observation, which is the focus of this minireview, are discussed here. The determination of the crystal structure of dimeric NGF revealed a novel three-dimensional fold. Each sub- unit consists of predominantly P-strand secondary struc- ture and an unusual clustering of three cystine bridges (McDonald et al., 1991). Subsequently, the structure of TGFj32 (Daopin et al., 1992a; Schlunegger and Griitter, 1992) showed a tertiary fold similar to NGF (Swindells, 1992; Murzin and Chothia, 1992). This observation has been confirmed by a structural comparison of the NGF and TGF82 molecules (Daopin et al., 1992b). The structure determination of PDGF-BB has provided another example of this structural fold (Oefner et al., 1992). Figure 1 shows a schematic summary of the three pro- tomer structures of NGF, TGFpP, and PDGF-BB that high- lights the common features characterizing the fold, partic- ularly the cystine knot motif (open circles) and two pairs of antiparallel 8 strands (labeled 81-84). In the NGF struc- ture, the disulfide bridges Cy~~-Cys~~ and Cys”-Cy~~~~ form a 1Cmembered ring through which the Cy~~~-Cys~ juncture passes. These three disulfide bridges have topo-
Scattering Spectra of Single Gold Nanoshells

Single particle dark field spectroscopy has been combined with high-resolution scanning electron and atomic force microscopy to study the scattering spectra of single gold/silica nanoshells. The plasmon resonant peak energies match those calculated by Mie theory based on the nanoshell geometry. The resonance line widths fit Mie theory without the inclusion of a size-dependent surface scattering term, which is often included to fit ensemble measurements. These results suggest that plasmon spectral measurements of nanoparticle ensembles are broadened due to particle inhomogeneity.
Multilayer-coating-induced aberrations in extreme-ultraviolet lithography optics

A multilayer coating alters the amplitude and phase of a reflected wave front. The amplitude effects are multiplicative and well understood. We present a mathematical formalism that can be used to describe the phase effects of coating in a general case. On the basis of this formalism we have developed an analytical method of estimating the wave-front aberrations introduced by the multilayer coating. For the case of field-independent aberrations, we studied both uniform and graded multilayer coatings. For the case of field-dependent aberrations, we studied only the effects of a uniform multilayer coating. Our analysis is based on a coated plane mirror tilted with respect to an incident converging beam. Altogether we have found, up to the second order, the following aberrations: a field-dependent piston, a field-squared-dependent piston, defocus, field-independent tilt, field-independent astigmatism, and anamorphic magnification. To obtain numerical results we apply our analysis to the specific case of a plane mirror tilted 8.2 deg with respect to an incident converging beam with a numerical aperture of 0.1. We find that the magnitudes of the field-independent aberration coefficients for the graded coating are approximately ten times smaller than those for the uniform coating. We show that a coating can introduce anamorphic magnification.
Highly conductive crystalline poly(2-methoxy-p-phenylene vinylene)

Abstract The synthesis and the structural, thermal and charge transport properties of poly(2-methoxy- p -phenylene vinylene) (MeOPPV) are reported. An inverse emulsion polymerization procedure for the preparation of the precursor polymer is described; this method provided improved yields with higher molecular weights. Also discussed are disorder and defects in the rigid conjugated crystalline polymer revealed by infra-red spectra and X-ray diffraction. It was observed that the charge transport properties of the polymer were affected by structural disorders. Films of MeOPPV became highly conductive when oxidatively doped, and they exhibited excellent air stability. The electron-donating substitution is shown to lower the ionization potential of the parent polymer, thereby improving the stability of the doped form. Differential scanning calorimetry and variable-temperature ultra-violet/visible spectra indicated that the polymer undergoes unusual backbone motions.
Enthalpies of Hydrogen Bonding in Psychotropic Drugs

The enthalpy of hydrogen bonding of some antipsychotic, antidepressant, anticonvulsant, and antianxiety agents with phenol, as determined from IR and NMR spectroscopic measurements, was shown not to be responsible for differences in activity within the drug classes. These results support a theoretical prediction advanced for anticonvulsant activity.
Groups versus individuals as the comparison unit in cognitive aging research

A database containing speed and memory data from 362 adults ranging from 20 to 79 years of age was analyzed (a) to determine the nature of the normative cross‐sectional age trends for each variable and (b) to estimate the sensitivity of within‐individual comparisons for detection of age differences. The cross‐sectional results revealed largely monotonic, linear declines for each variable, a trend evident in each quartile of the sample of individuals from each decade. Because the consistency of scores from the same individual within the same measurement occasion was rather low, it was inferred that it may prove very difficult to detect the effects of aging within individual adults.
Utilizing Nurse Practitioners to Provide Health Care for Elderly Patients in Massachusetts Nursing Homes

This study evaluates the nursing contribution to the process of care utilizing nurse practitioners (NPs) to provide health care for nursing home patients in Massachusetts. Using magnetic tapes of data collected through retrospective chart reviews of 2,651 patient records in 110 Massachusetts nursing homes, comparisons were made of the process of care variables of NP/physician team and physician-only models of care. Results from discriminant function analysis revealed process of care variables did discriminate between the two models. The conclusion that NPs provide not only a substitutive role to that of medical care but also a complementary one should be instrumental in enabling policy decisions that encourage the full utilization of NPs.
Experimental investigation and model development for a harmonic drive transmission

Harmonic drive transmissions (HDTs) are compact, low-backlash, high-ratio, high-resolution rotary motion transmissions. One application to benefit from these attributes is the revolute joint robot. Engineers at the Advanced Photon Source (APS) are investigating the use of this type of robot for the positioning of an x-ray detector; understanding the properties of the robot components is crucial to modeling positioner behavior. The robot bearing elements had been investigated previously, leaving the transmission as the missing component. While the benefits of HDTs are well known, the disadvantages, including fluctuating dissipation characteristics and nonlinear stiffness, are not understood as well. These characteristics can contribute uncontrolled dynamics to the overall robot performance. A dynamometer has been constructed at the APS to experimentally measure the HDT's response. Empirical torque and position data were recorded for multiple transmission load cases and input conditions. In turn, a computer model of the dynamometer HDT system was constructed to approximate the observed response.
Continuous Improvement of H-Mode Discharge Performance with Progressively Increasing Lithium Coatings in the National Spherical Torus Experiment

Lithium wall coatings have been shown to reduce recycling, improve energy confinement, and suppress edge localized modes in the National Spherical Torus Experiment. Here, we show that these effects depend continuously on the amount of predischarge lithium evaporation. We observed a nearly monotonic reduction in recycling, decrease in electron transport, and modification of the edge profiles and stability with increasing lithium. These correlations challenge basic expectations, given that even the smallest coatings exceeded that needed for a nominal thickness of the order of the implantation range.
Demonstration of an elastically coupled twist control concept for tilt rotor blade application

The purpose of this Note is to present results from an analytic/experimental study that investigated the potential for passively changing blade twist through the use of extension-twist coupling. A set of composite model rotor blades was manufactured from existing blade molds for a low-twist metal helicopter rotor blade, with a view toward establishing a preliminary proof concept for extension-twist-coupled rotor blades. Data were obtained in hover for both a ballasted and unballasted blade configuration in sea-level atmospheric conditions. Test data were compared with results obtained from a geometrically nonlinear analysis of a detailed finite element model of the rotor blade developed in MSC/NASTRAN.
Effects of hyaluronan supplementation on cryopreserved equine spermatozoa hyaluronan and cryopreserved equine spermatozoa

Abstract Addition of hyaluronan, a nonsulfated glycosaminoglycan, to fresh and frozen thawed human semen results in substantial retention of motility over time. Hyaluronan also has been reported to preserve postthaw viability and maintain membrane stability of boar spermatozoa. Therefore, experiments were designed to investigate the use of a commercially available hyaluronan (Map-5, Bioniche Animal Health, Inc., Athens, GA) in freezing extender for cryopreservation of equine spermatozoa. In experiment 1, aliquots from ejaculates were supplemented before freezing with one of four levels of hyaluronan: 100 μg/mL, 200 μg/mL, 400 μg/mL, and 1000 μg/mL along with an untreated control. No differences in sperm motility, assessed by computer-assisted sperm motility analysis (CASA), were found for any treatment at times 0, 30, or 60 minutes postthaw. Decreases in motility were noted in the highest hyaluronan group (1,000 μg/mL) after 90 and 120 minutes of incubation. Sperm viability, as assessed using SYBR-14/propidium iodide staining, was decreased ( P P P
First-principles-based Monte Carlo methodology applied to O/Rh(100)

Abstract A kinetic Monte Carlo algorithm was developed to simulate the temperature-programmed desorption of oxygen on Rh(100). The interactions between surface oxygen atoms were derived by a bond order conservation (BOC) model that was parameterized from a database of ab-initio density functional quantum chemical results. The intrinsic activation barriers and heats of adsorption were taken from the DFT-calculated database. The effect of coverage on these intrinsic parameters was calculated internal to the simulation at each site throughout the simulation using the modified BOC model. The Monte Carlo simulation was subsequently used to follow the coverage-dependent desorption kinetics for O/Rh(100). The simulated temperature-programmed desorption peaks of 820, 925, and 1250 K compare favorably with experimental peak temperatures at 810, 920, and 1200 K. Below 0.3 ML, oxygen prefers the fourfold hollow sites and orders in a (2×2) arrangement. Between 0.3 and 0.5 ML, oxygen begins to reorder due to repulsive lateral interactions. The results shown here indicate that oxygen begins to occupy bridge sites. Although reconstruction is not explicitly considered, it would likely demonstrate similar effects of reducing repulsive interactions through a change in the surface structure.
Sphincterotome stricturoplasty for long ampullary stenoses and benign biliary strictures (with video)

Long ampullary stenoses and fibrotic distal biliary strictures are not infrequently encountered during endoscopic retrograde cholangiopancreatography (ERCP). Instead of balloon dilation and stenting, we propose that these strictures can be managed with sphincterotome stricturoplasty (SS) during the initial ERCP. To report our clinical experience with SS for benign distal biliary strictures. Review on prospectively collected data. All (consecutive) patients who underwent ERCP and SS performed by the authors in a 12-month period. Long ampullary stenosis and/or distal biliary stricture is defined as significant narrowing of CBD from the level of duodenal wall into the common bile duct (CBD) after initial sphincterotomy. The upstream CBD is dilated. Despite adequate ES, contrast drainage is poor due to the downstream stricture. SS was performed using the same sphincterotome in slightly bowed position under endoscopic and fluoroscopic guidance. The cutting wire was placed parallel to the superior border within the stricture and incising the stenosis. In cases of relatively long strictures, during initial SS the majority of the cutting wire was inside the biliary opening. This differs from ES, where about one-third to one-half of the length of cutting wire is outside the ampulla. Clinical data, hospital course, procedure-related complication rates, and outcomes were prospectively collected in a database. During the study period, 308 ERCPs were performed. Benign and short (≤15 mm in length) distal biliary strictures were observed in 25 patients. Mean ± SD stricture length was 7.4 ± 3.0 mm. The presumed etiologies for these strictures were choledocholithiasis (n = 22) and postsphincterotomy stenosis (n = 3). There was no perforation, post-ERCP pancreatitis, postsphincterotomy bleeding, or cholangitis. To date, none of these patients who had SS have needed follow-up ERCP. Single-operator experience, limited follow-up period. Compared with balloon stricturoplasty ± biliary stenting, SS is a simple and cost-effective alternative option in managing long ampullary stenosis and/or distal fibrotic biliary stricture during the initial ERCP.
Simulated performance of a RISC-based multiprocessor using orthogonal-access memory

Abstract This paper reports the simulated performance of the Orthogonal MultiProcessor (OMP) under development at the University of Southern California. The OMP is simulated with hardware parameters used in the system design. The results are obtained by using a CSIM-based multiprocessor simulator developed at USC. The OMP was evaluated in SPMD (Single-Program and Multiple-Data-streams) mode, which demands interprocessor synchronizations at the subprogram level, rather than at the instruction lockstep level as in an SIMD machine. The simulated OMP consists of 16 Intel i860 processors and 256 memory modules interconnected by two-dimensional spanning buses. The simulated benchmarks include unfolded matrix multiplication, two-dimensional FFT, orthogonal sorting, and parallel pattern clustering. These simulation experiments resulted in a speedup factor between 10 and 15, as compared with a system using a single i860 processor. The paper also reports program and data partitioning methods for the OMP and discusses the effects of synchronization and vector register windows on the multiprocessor performance.
1,3-Diphenyl-1,3-cyclopentanediyl: A remarkably stable localized biradical

Abstract The triplet ground state of 1,3-diphenyl-1,3-cyclopentanediyl ( 3 ) has been directly observed by matrix-isolation EPR spectroscopy at both 4 K and 77 K.