cssi/SciSciGPT-SciSciNet huggingface dataset:
Prefabrication provides synapses on demand

The process of synaptogenesis between neurons is by no means uneventful. Axonal growth cones and dendritic filopodia rapidly extend and retract as they desperately attempt to find appropriate partners to form connections required for cell survival. During development in mammalian cortex, synaptogenesis proceeds at an amazing pace with the majority of connections formed during a brief 5-day window in the second postnatal week. The advent of powerful imaging techniques has allowed direct visualization of synaptogenesis in vivo and in vitro. Little is known, however, about how synaptogenesis is initiated, the molecular events involved and the time course of these processes.
The Lutong of Kuala Selangor

A field study of the Lutong, (Presbytis cristatus) was conducted in Malaya. Lutong troops were observed for more than 1000 hours and were found to be markedly territorial. Only one control male lives in each troop and he actively defends the territory against incursions by other lutong males. Each troop moves slowly through its territory feeding and resting and comes into frequent visual contact with adjacent troops. Each troop is a well organized social unit but only the control males show consistent hostility to one another when troops meet. Grooming, play, sexual responses, maternal behavior and agonistic episodes are described as well as travel, feeding and diurnal patterns. These patterns appear similar to those reported in other Presbytis species, but contrast markedly with macaque and baboon reports. Differences in behavior between species of Presbytis do not exceed differences reported in the same species by different observers in different areas.
Radiative transfer in an anisotropically scattering vegetative medium

Abstract In this paper, we describe a method to compute the angular distribution of multiply scattered radiation in and from a vegetative canopy. The canopy scattering phase functions are derived from consideration of both the individual leaf scattering behavior and the geometrical disposition of such leaves in an elementary canopy space. The single scattering albedos are treated as dependent on the incident beam direction. The radiative transport problem is approximated successively for each order of scattering using a hydbrid formulation based on the principles of invariance. The method was used to compute the anisotropy in the scattered fluxes, and reflectance from a soybean canopy had a strong specular component for oblique angles of incidence of the collimated flux.
The Effect of Glycerol and Its Removal on Cock Spermatozoa Concanavalin A and Cationized Ferritin Binding Sites

Abstract Concanavalin A (Con A) and cationized ferritin (CF) were utilized to assess the effects of glycerol and its removal on their respective sperm plasma membrane binding sites. Diluted semen was equally divided: One part diluted with a diluent that was 15% glycerol by volume and the other was unchanged. Sperm labeling with Con A and CF was done with diluted spermatozoa, diluted spermatozoa held for 3 hr. at room temperature, glycerol-treated spermatozoa and dialyzed, glycerol-treated spermatozoa. Both probes uniformly labeled the surface of spermatozoa from all treatments. The plasma membrane of some glycerol-treated spermatozoa and of some dialyzed spermatozoa exhibited disruption in the form of ruffling, ballooning, and discontinuity. Nearly 60% of the dialyzed, glycerol-treated spermatozoa were observed to have some surface membrane irregularity. Glycerol-induced osmotic effects may have resulted in the surface damage. In addition, glycerol’s ability to destabilize membranes may have rendered the sperm’s plasmalemma more labile thus augmenting the osmotic-induced damage. It was concluded that the loss of fertility after vaginal insemination of glycerol-treated spermatozoa did not appear to be associated with alterations of the surface glycoproteins which bind Con A and CF. However, it may be related to the loss of plasma membrane integrity.
Government policy cross effects: The cotton and dairy programs' influence on alfalfa hay markets

To illustrate the magnitude of government policy impacts on nonprogram products, estimates are presented of the 1986–1987 crop year effects of both the 1986 cotton and dairy programs on the Arizona alfalfa hay market. These policy “cross effects” are calculated from simulation results of a simple econometric model. The estimated impact of $8.91 per ton represents a nine percent reduction in gross unit revenues from hay.
Laser-induced damage measurements in CdTe and other II-VI materials.

Results of laser-induced damage measurements in CdTe and other selected II–VI materials are reported. These studies were conducted using pulsed 1.06-μm radiation from a Nd:YAG laser. The laser pulse width was varied from ~40 to 9000 psec (9 nsec). The laser-induced surface breakdown irradiance measured for CdTe over this pulse width range scaled as tp-1/2 [tp is the laser pulse width (FWHM)]. This indicates that laser-induced damage in this material is due to linear absorption by a thin surface contamination layer.
Mechanism of Very Large Scale Assembly of SWNTs in Template Guided Fluidic Assembly Process

Very large scale patterned single-walled carbon nanotube (SWNT) networks were fabricated using a newly developed template guided fluidic assembly process. A mechanism for SWNT assembly and their control is described here. To maximize the directed assembly efficiency of SWNTs toward a wafer level SWNT deposition, Si or SiO2 substrate was pretreated with precisely controlled SF6, O2, and Ar plasma. Chemical and physical properties of the surface were characterized using several surface characterization techniques to investigate and control the mechanism of SWNT assembly. We found that hydrophilic chemical groups such as hydroxides were created on the silicon or silicon oxide surface through the controlled plasma treatment and fluidic SWNT dip-coating process. Also we found that nanoscale rough surface structures formed during the plasma treatment significantly increased the number of dangling bonds and hydroxide functional groups on the surface. These combined chemical and physical enhancements that attract...
The Effect of Computerized Provider Order Entry on Medical Students’ Ability to Write Orders

Background: Computerized provider order entry (CPOE) is being implemented at increasing numbers of U.S. hospitals, yet the effects of CPOE on medical student education are largely unstudied. Purpose: The objective is to investigate the effects of CPOE on medical students’ ability to write orders for patients. Methods: One hundred forty-three medical students who began their Basic Medicine clerkship between March 2003 and April 2004 were asked to write mock admission orders for a patient with pneumonia after the 1st month of their clerkship. Students had spent the month at 1 of 3 hospitals: 1 using CPOE, 1 paper orders, and 1 that began using CPOE midway through this study. Admission orders were scored for the presence of specific orders and features. Results: One hundred twenty students attempted to write admission orders. Students who trained at hospitals using CPOE and those who trained at hospitals using paper orders included expected basic, lifesaving, and higher level orders at similar rates. No sign...
GROUP AND INDIVIDUAL PERFORMANCE IN PROBLEM SOLVING RELATED TO PREVIOUS EXPOSURE TO PROBLEM, LEVEL OF ASPIRATION, AND GROUP SIZE

Different results from studies in problem solving conducted 25 years apart have led these authors to a consideration of the part increased experience with puzzles and problems over a generation has played in producing such differences. The relation of previous experience to the level of aspiration of the individual, alone and operating in groups of varying sizes, is detailed in this study.
Some influences of approximate values for velocity, density and total temperature sensitivities on hot wire anemometer results

There is a renewed interest in hot wire anemometry at transonic speeds. Recent results were published which indicate that at transonic speeds a heated wire is sensitive only to mass flow and total temperature, results similar to those obtained for supersonic flows. Other results were obtained to show that the sensitivity is a function of velocity, density, and total temperature, results in agreement with many of those obtained in the 1950s. An analysis of anemometry results was made to evaluate possible errors when various assumptions were made concerning the sensitivity of a heated wire to fluid flow variables.
Distant Corners: American Soccer’s History of Missed Opportunities and Lost Causes

David Wingerin (Philadelphia: Temple University Press, 2011). Pp. 264. ISBN: 978-1439906309 The world’s most popular game has struggled for attention in the crowded American sports scene. Millions ...
Integrated Optics Techniques

Optical waveguides having cross-sectional dimensions on the order of a few micrometers on a side and lengths on the order of a few centimeters have been fabricated using photo-lithography and electron beam lithography. These guides can be produced in single crystal materials suitable for optical switches, lasers and detectors. The waveguide devices are often more efficient and potentially less expensive to construct than their bulk counterparts. Moreover, when the demand is sufficiently strong, means may be found to design complex integrated optical circuits consisting of networks of these wave-guide elements connected on a single substrate. The theory and techniques of optical waveguide devices, which have been reviewed elsewhere,1,2 will be discussed briefly. An especially simple method of producing waveguide switches is by diffusion of metal into LiNb03,4 The photomask may be conveniently made using the EBES (electorn beam exposure system) designed for integrated electronic circuits.5 The high resolution metal pattern required for preparing the diffused waveguides is made by a positive-resist lift-off method.6 Waveguide patterns can also be fabricated using a positive electron-beam resist and a scanning electron microscope.7© (1977) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Response to Letter by Taggar et al

Response: Thank you for your interest in our work. We agree with you that no model of stroke risk estimation is ideal. We also recognize the inadequacy of the schema with respect to the moderate risk patient whose management …
Assisting Students with Difficult Textbooks: Teacher Perceptions and Practices.

Abstract The primary purpose of this investigation was to examine teachers' perceptions and practices pertaining to textbook adaptations and instructional strategies to facilitate understanding of textual material. Subjects included 20 elementary, 20 middle, and 20 high school teachers. Each teacher completed the Textbook Adaptation Evaluation Instrument, a Likert‐type scale that consists of 31 textbook adaptations. Teachers rated each adaptation in respect to desirability, feasibility, and use. Analyses provided a comparison of teachers' overall rankings of desirability, feasibility, and use for each of the three grade groups (elementary, middle, and high). Findings are discussed in respect to types of adaptations preferred, grade grouping differences, and implications for future research.
Testosterone regulates galanin gene expression in the bed nucleus of the stria terminalis

The regulation of galanin (GAL) gene expression in the bed nucleus of the stria terminalis (BNST) by testosterone (T) was investigated using in situ hybridization histochemistry. Castration of adult male rats significantly reduced both the number of cells which expressed GAL mRNA and the average number of grains per cell. These effects were reversed by testosterone treatment. Testosterone stimulates GAL gene expression in the same neurons that have previously been shown to exhibit steroid regulation of vasopressin gene expression.
Environment, disease and mortality in early Virginia.

Abstract Early Virginia (1607-24) was a nightmarish world of disease and death, perhaps uncurpassed in the annals of English colonization. Typhoid fever and dysentery visited Jamestown in recurrent epidemics killing 30 per cent or more of the colonists with each onslaught. Yet Jamestown endured because the leaders of the Virginia Company misapprehended the nexus between the estuarine environment and water-borne, non-immunizing diseases. Each summer, death stalked the town as invading salt water pushed up the estuary and concentrated pathogens in the town's water supply. The prevention of disease and death required the abandonment of Jamestown and relocation into healthier niches, which occurred with the dissolution of the Virginia Company in 1624.
Regulation of energy metabolism by creatine in cardiac and skeletal muscle cells in culture

Abstract Cardiac and skeletal muscle cells grown in culture were used in experiments designed to test the regulatory function of creatine. An increased concentration of intracellular phosphorylcreatine resulted from the addition of creatine to the growth media and the addition of metabolic inhibitors prevented the new high steady state concentration without depletion of ATP. With 1-fluoro-2, 4-dinitrobenzene the high concentration of phosphorylcreatine remained unchanged, while ATP was depleted. The use of the inhibitors provided additional evidence for creatine as the effector molecule in a feedback regulation of energy production, and for phosphorylcreatine in the regulation of energy charge at the contractile site. The effect of creatine on the fusion of myoblasts into myotubes supported its role in the control of cellular functions other than those involved in the energy metabolism. The correlation of the growth of muscle with increased muscular activity might be mediated through creatine, the end product of muscle activity. Creatine, synthesized in tissues other than muscle, might be involved in the coordination of muscle development throughout the body. Furthermore, it is suggested that the metabolic regulatory function of creatine is limited to the cells which do not synthesize creatine de novo , while in the tissues, such as the liver and kidney which have the mechanism for de novo synthesis of creatine, the absence of mitochondrial CPK precludes metabolic regulation of ∼ P synthesis by creatine.
Diagnosis of aortoenteric fistulas with CT angiography.

Purpose To describe the diagnostic findings of primary and secondary aortoenteric fistulas (AEFs) at computed tomographic (CT) angiography in a cohort of patients known to have AEF and to correlate those findings with those from endoscopic gastroduodenoscopy (EGD) and surgery. Materials and Methods CT angiography was performed in nine patients with AEF. There were four men and five women aged 43–85 years (mean age, 67 years). All CT angiograms were retrospectively reviewed for signs of AEF. Reports from EGD, surgery, and pathologic examination were also reviewed. Results One patient had a primary AEF, and eight patients had a secondary AEF. Findings at CT angiography were suggestive of the diagnosis in all nine patients. The two definitive CT angiographic findings were identification of the graft within the bowel lumen in two patients (22%) and active extravasation in one patient (11%), allowing the definitive diagnosis in three of the nine patients (33%). Secondary signs, which helped predict the high likelihood of the diagnosis but could also be seen in graft infection or inflammation without AEF, were as follows (in descending order of frequency): effacement of the periaortic or perigraft fat plane and the fat plane between the aorta and bowel (nine patients, 100%), perigraft soft tissue (nine patients, 100%), bowel wall thickening adjacent to the graft (eight patients, 89%), perigraft fluid (seven patients, 78%), perigraft hematoma (six patients, 67%), pseudoaneurysm or aneurysm bulge (six patients, 67%), ectopic gas (five patients, 56%), and dystrophic vascular graft calcification (one patient, 11%). The diagnosis was confirmed surgically in seven patients and with clinical follow-up in two. Conclusion CT angiography is well suited for helping make or suggesting the diagnosis of AEF and is potentially more accurate than EGD.
It’s never too late to remediate: Teaching word recognition to students with reading disabilities in grades 4–7

Twenty children in fourth through seventh grade participated in 16 one-hour individual tutorials over a four-month period. Half of the children received structural analysis and alphabet principle training; half received only alphabetic principle training; all received training in orthographic and phonological skills, practice in oral reading of connected text, and monitoring strategies for comprehension. Results showed that the children improved reliably in reading and related measures. Treatment condition did not predict rate of growth. Only rapid automatic naming of letters predicted response to intervention and only on rate of real word reading. Results of this study indicate that upper elementary and middle school students who have not yet mastered accuracy and automaticity of word recognition should be given explicit instruction in word recognition, especially in the alphabetic principle. The benefits of structural analysis training were evident only in trends for individual students on hierarchical linear modeling (HLM) growth analyses.
A stochastic modeling of early HIV-1 population dynamics

Abstract In a recent paper, Tuckwell and Le Corfec [J. Theor. Biol. 195 (1998) 450–463] applied the multi-dimensional diffusion process to model early human immunodeficiency virus type-1 (HIV-1) population dynamics. The purpose of this paper is to assess certain features and consequences of their model in the context of Tan and Wu's stochastic approach [Math. Biosci. 147 (1998) 173–205].
Stress transmission anomalies in femoral heads altered by aseptic necrosis

Abstract The effects of aseptic necrosis upon load transmission patterns in the adult femoral head are explored by means of a two-dimensional finite element model. Experimental measurements of the modulus reductions of necrotic human cancellous bone are incorporated in the computation, by reducing the elasticity matrix values within the simulated infarct regions. Stress distribution patterns characterizing the effects of parametric variations of the stiffness deficit, and the lesion base width, depth, and apex width are presented. The data show that the intact viable bone surrounding a weakened infarct preferentially takes up additional load, but that the degree of stress relief achieved is a strong function of the infarct geometry. The results indicate that osteotomies undertaken to provide stress relief are likely to be most effective for narrow infarcts, and that achieving stress relief for the superior aspect of the lesion should be the principal objective of such procedures.
Single European Sky and the functional airspace blocks: Will they improve economic efficiency?

The paper examines the potential economic efficiency of on-going changes in the European air traffic control system. Air navigation services in Europe are undergoing a process of consolidation and technological changes known as the Single European Sky initiative. The ultimate aim is to shift the industry from a paradigm based on national borders, to one where operational efficiency is the goal. One of the key components of the movement toward this is the notion of functional airspace blocks (FABs) whereby blocks of airspace are combined as a precursory to total unification of the system. To study the effects that those changes might have on the economic efficiency of the system, a data envelopment analysis framework is used. Although these FABs are not yet deployed, it is possible to simulate, ceteris paribus, how these different systems would have ranked in terms of economic efficiency by using data for each individual air navigation service provider.
Identifying the pairing symmetry in the Sr 2 RuO 4 superconductor

We have analyzed heat capacity and thermal conductivity measurements of ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ in the normal and superconducting state and come to the conclusion that an order parameter with nodal lines on the Fermi surface is required to account for the observed low-temperature behavior. A gapped order parameter is inconsistent with the reported thermodynamic and transport data. Guided by a strongly peaked dynamical susceptibility along the diagonals of the Brillouin zone in neutron-scattering data, we suggest a spin-fluctuation mechanism that would favor the pairing state with the gap maxima along the zone diagonals (such as for a ${d}_{\mathrm{xy}}$ gap). The most plausible candidates are an odd parity, spin-triplet, f-wave pairing state, or an even parity, spin-singlet, d-wave state. Based on our analysis of possible pairing functions we propose measurements of the ultrasound attenuation and thermal conductivity in the magnetic field to further constrain the list of possible pairing states.
Renormalization of the vector current in QED

It is commonly asserted that the electromagnetic current is conserved and therefore is not renormalized. Within QED we show (a) that this statement is false, (b) how to obtain the renormalization of the current to all orders of perturbation theory, and (c) how to correctly define an electron number operator. The current mixes with the four-divergence of the electromagnetic field-strength tensor. The true electron number operator is the integral of the time component of the electron number density, but only when the current differs from the [overline MS]-renormalized current by a definite finite renormalization. This happens in such a way that Gauss's law holds: the charge operator is the surface integral of the electric field at infinity. The theorem extends naturally to any gauge theory.
Laryngeal Effects of Antigen Stimulation Challenge with Perennial Allergen Dermatophagoides Pteronyssinus

Abstract Objective We conducted a pilot study to assess the effects of antigen stimulation on the appearance and function of the larynx. Study design and subjects The prospective, double-blind, randomized study included 9 adult patients with a skin-prick test positive for Dermatophagoides pteronyssinus . Main outcome measures Subjects were blindly challenged via nebulizer with either an active antigenic suspension or placebo. Baseline and 30-minute evaluations of the larynx were performed. Assessments included subjective voice and videostroboscopic assessments, acoustic analysis of voice, speech aerodynamic testing, and allergy and voice handicap questionnaires. Results Although both inflammation and increased mucus were noted, there were no significant differences between the antigen- and placebo-exposed subjects on any of the measures obtained. Conclusions Our preliminary investigation was not successful in demonstrating a direct causal relationship between antigen exposure and physical or functional changes in the larynx. Future studies will involve modifications to our current methodology, including increasing the concentration of antigen, prolonging the exposure time, and observing for late phase responses.
Synthesis of tire equations for use in shimmy and other dynamic studies

.4 system of transfer functions relating the cornering force and aligning torque of a rolling pneumatic tire to its yaw angle and lateral displacement are developed from experimental and theoretical frequency response curves. These transfer functions consist of ratios of polynomials in the Laplaciari variable s, which lead to a system of linear constant coefficient differential equations. The resulting equations have the advantage of both simplicity and accuracy and are ideally suited for use in dynamical analysis such as the study of wheel shimmy phenomena. These differential equations, along with the corresponding experimental frequency response curves, are compared with those derived from the widely used Moreland tire theory. This comparison reveals a number of inadequacies in the Moreland theory.
Fiber Bragg grating OSNR monitor

A novel optical signal-to-noise ratio (OSNR) monitor has been proposed and demonstrated. The device is completely passive, very simple, compact and cost effective. More than 30 dB dynamic range polarization insensitive OSNR monitoring has been achieved.
Electronic structure and properties of YBa2Cu4O8

Abstract The electronic structure and properties of the new high- T c superconductor, YBa 2 Cu 4 O 8 (called Y124), have been determined using the local-density full potential linearized augmented plane wave method. Despite the additional layer of Cu(1)-O(1) chains relative to YBa 2 Cu 3 O 7 (called Y123): (i) the band structure at and near E F is simplified with the absence of the Cu(1)-O(1) dpπ band which plagued the Y123 results; (ii) the Fermi surface is also simplified, shows greater nestings, but still cannot be represented by a simple nearest neighbor tight-binding Hamiltonian model; (iii) the density of states of E F is one-half of that in Y123 (in good agreement with experiment). Further, as a result of (i) and (iii) together with the lower Madelung potential at the O(1) sites, which leads to the higher binding energy for O(1) the Cu(1)-O(1) chains are now stable and Y124 should be stable in its oxygen stoichiometry — as its observed.
621 TISSUE DISTRIBUTION OF SELENIUM (Se) IN SUCKLING RAT PUPS

The information on Se is inadequate with regard to the relative tissue distribution and the reversibility of accumulation after the cessation of exposure in sucking subjects after the administration of the Se to their lactating mothers. Two lactating rat dams (dam A and B) were provided sodium selenite in their drinking water at the concentration of 0 and 3 ppm, respectively. There were 15 experimental pups (B) and 13 pups in control group (A). Experiment was carried out during the first 6 weeks post partum. Third group (C) comprised of 6 pups who were separated from dam B and adopted by dam A after the first 3 weeks. Se concentrations (μg/gm tissue) follows (X±SD): Standard at experimental versus control:*=<0.05, **=<0.01 Se concentrations were higher in tissues of pups B, however, pups C showed a reversal yet with persistence of higher levels in hair (p<0.05). There appears to be a transfer and accumulation of Se in tissues of suckling pups which is reversible. Hair Se determinations may be useful for assessment of internal organ Se status in Se exposed suckling subjects.
Use of single-dose epidural morphine in a patient undergoing an abdominal aortic aneurysm resection

Abstract To avoid possible trauma to the epidural venous plexus in a 56-year-old male who presented for abdominal aortic aneurysm resection, the authors preoperatively injected a single dose of epidural morphine rather than inserting an indwelling epidural catheter. The patient's intraoperative anesthetic requirements appeared to have been decreased, he was extubated shortly after the end of the procedure, and he experienced good postoperative analgesia. No untoward neurologic sequelae occurred. The authors feel that a single dose of epidural morphine, compared to epidural catheter placement when systemic heparinization is planned, decreases intraoperahve anesthetic requirements, provides good post-operative analgesia, and may have the benefit of decreasing the possibility of epidural hematoma formation.
Tuberous sclerosis: from tubers to mTOR.

Summary Tuberous sclerosis (TSC) is an autosomal dominant hamartoma syndrome whose causative genes (TSC1 and TSC2) were identified 5 and 9 years ago respectively. Their encoded proteins are large, and apart from a strong binding interaction with each other, relatively little was known about their biochemical function. Recent studies in Drosophila have pinpointed a critical function for the Drosophila TSC1/TSC2 homologues in the regulation of cell size. Epistasis experiments and a variety of biochemical studies that followed have indicated a critical function for these proteins in the highly conserved PI-3-kinase-Akt-mTOR signalling pathway. The clinical problem Tuberous sclerosis (TSC) is an autosomal dominant hamartoma syndrome with a prevalence of 1 in 6000 to 10000 births. Most of the hamartomas and other lesions seen in tuberous sclerosis are very unusual in the general population, such that the formal diagnostic criteria (Roach et al. 1998) may be condensed fairly accurately to the following simple formulation: a patient has TSC if they have two different types of classic TSC hamartoma. Most TSC patients have hamartomas in the brain, skin, kidneys, and heart (Gomez et al. 1999). Involvement of the lung, gastrointestinal tract, bones, retina, and gingiva are also often seen. A hamartoma is a group of dysplastic, disorganized cells within an organ with some growth potential. In aggregate the TSC hamartomas occurring in the brain, skin, kidneys and heart have no common histologic features, but often consist of multiple cell types. During childhood the predominant morbidity in TSC is neurologic, due to involvement of the brain by the hallmark cortical tubers. Seizures are seen in about 90% of patients, often presenting as infantile spasms, and mental retardation and a
PKC α regulates thrombin-induced PDGF-B chain gene expression in mesangial cells

Thrombin is a potent mitogen for mesangial cells and stimulates PDGF B-chain gene expression in these cells. It also activates phospholipase C (PLC) resulting in an increase in cytosolic Ca2+ and diacylglycerol (DAG) that are the physiological activators of protein kinase C (PKC). Immunoprecipitation of specific PKC isotypes from thrombin-stimulated mesangial cells with subsequent measurement of their enzymatic activity shows activation of Ca2+-dependent PKC α and Ca2+-independent PKC Σ in a time dependent manner. Optimum activation of both of these isozymes was obtained at 60 minutes. PKC α activity increased 83% over basal while activity of PKC Σ increased 104%. Prolonged exposure of mesangial cells to phorbol myristate acetic acid (PMA) inhibited the enzymatic activity of PKC α but not PKC Σ. This inhibition of PKC α had no effect on thrombin-induced DNA synthesis but abolished PDGF B-chain gene expression induced by thrombin. These data provide the first evidence that PKC α activation is necessary for thrombin-induced PDGF B-chain gene expression but not for thrombin-induced DNA synthesis.
Organ weights in rats with activity-stress ulcers

Rats were housed in activity cages and fed 1 h daily. When these rats died, wet and dry weights were obtained for adrenals, spleen, liver, kidney, heart, stomach rumen, and stomach body. Most activity rats, as compared to food-yoke control and home-cage control rats, had lesions in the glandular stomach. Adrenal and heart weights suggested that activity rats had been subjected to some degree of stress. Characteristic starvation effects, such as rumenal lesions and edema of stomach tissue, were not observed in activity rats.
Three- and Four-Year-Old Children's Ability to Use Desire- and Belief-Based Reasoning.

Recently, several researchers have claimed that young 3-year-old children rely on desire when making behavioral predictions and that this causes poor performance on standard measures of false-belief understanding. This study investigates this claim. Results suggest that young children may, in fact, be using desire to predict behavior in these standard paradigms. Importantly, it is the desires of the agent, not the child's own desires that are used to make the prediction. Further, older preschool children also have some difficulty coordinating both belief and desire when processing demands are increased.
A block design for split-field tests of accelerator alignment.

We present a block design that facilitates split-field tests, a technique frequently employed to assess several potential misalignments in linear accelerators. Two tests are possible with this device using: (1) opposed collimator angles and (2) opposed gantry angles. The first test is sensitive to jaw symmetry only. In the second test, the alignment of one field edge indicates gantry sag, while the other field edge is sensitive to the combined effects of jaw asymmetry, misalignment of the beam spot, and misalignment of the gantry and collimator rotation axes. The block arrangement consists of a pattern of three polygons cast in lead or Cerrobend. The assembly mounts in the accessory tray of the accelerator and allows all necessary exposures to be taken in a single room entry. Any field size up to 24 cm can be tested with the assembly constructed here. A simultaneous test of light field-radiation field coincidence can also be accommodated. Exposed films with a prototype device show that offsets of ±1 mm are readily visible. The block design facilitates the required measurements for split-field tests and makes this a practical technique for routine quality assurance on a linear accelerator.
Communication: Direct determination of triple-point coexistence through cell model simulation

In simulations of fluid-solid coexistence, the solid phase is modeled as a constrained system of Wigner-Seitz cells with one particle per cell. This model, commonly referred to as the constrained cell model, is a limiting case of a more general cell model, which is formed by considering a homogeneous external field that controls the number of particles per cell and, hence, the relative stability of the solid against the fluid phase. The generalized cell model provides a link that connects the disordered, fluid phase with the ordered, solid phase. In the present work, the phase diagram of this model is investigated through multicanonical simulations at constant pressure and histogram reweighting techniques for a system of 256 Lennard-Jones particles. The simulation data are used to obtain an estimate of the triple point of the Lennard-Jones system. The triple-point pressure is found to be higher compared to previous work. The likely explanation for this discrepancy is the highly compressible nature of the gas phase.
How dihydrofolate reductase facilitates protonation of dihydrofolate.

Dihydrofolate Reductase (DHFR) catalyzes the reduction of dihydrofolate (H2F) to tetrahydrofolate. On the basis of 10−12.5 ns molecular dynamics simulations of two conformations (closed and occluded) of the ternary DHFR/NADPH/H2F complex from Escherichia coli and a free energy perturbation approach, we have calculated the pKa value for the N5 atom in H2F. Our results suggest that the N5 atom in H2F is responsible for the pH dependency of the catalyzed reaction, meaning that DHFR facilitates protonation of H2F by approximately 4 pKa units. The mechanism behind this increase is due to favorable electrostatic interactions between the Asp27 residue and a proton at the N5 atom. The electrostatic interactions are enhanced by a hydrophobic active site, which to a large extent is made hydrophobic by the M20 loop in DHFR. Moreover, we find that the conformation imposed on H2F by DHFR to some extent also favors protonation of the N5 atom. Our results add support to previous findings and suggestions by Callender and...
Issues of regret in women with contralateral prophylactic mastectomies.

Background: Patients with a history of carcinoma of one breast have an estimated risk of 0.5% to 0.75% per year of developing a contralateral breast cancer. This risk prompts many women to consider contralateral prophylactic mastectomy (CPM) as a preventive measure. Virtually nothing is known about patient acceptance following CPM. We have developed a National Prophylactic Mastectomy Registry comprised of a volunteer population of 817 women from 43 states who have undergone prophylactic (unilateral or bilateral) mastectomy. Methods: Of the 346 women with CPM who responded to national notices, 296 women returned detailed questionnaires. The information obtained included patient demographics, family history, reproductive history, ipsilateral breast cancer staging and treatment, as well as issues involving the CPM. Results: At median follow-up of 4.9 years, the respondents were primarily married (79%), white (97%) women who had some level of college education or above (81%). These women cited the following reasons for choosing CPM: (1) physician advice regarding the high risk of developing contralateral breast cancer (30%); (2) fear of developing more breast cancer (14%); (3) desire for cosmetic symmetry (10%); (4) family history (7%); (5) fibrocystic breast disease (4%); (6) a combination of all of these reasons (32%); (7) other (2%); and (8) unknown (1%). Eighteen of the 296 women (6%) expressed regrets regarding their decision to undergo CPM. Unlike women with bilateral prophylactic mastectomies, regrets tended to be less common in the women with whom the discussion of CPM had been initiated by their physician (5%) than in the women who had initiated the discussion themselves (8%) (P = ns). Family history and stage of index lesion had no impact on regret status. The reasons for regret included: (1) poor cosmetic result, either of the CPM or of the reconstruction (39%); (2) diminished sense of sexuality (22%); (3) lack of education regarding alternative surveillance methods or CPM efficacy (22%); and (4) other reasons (17%). Conclusions: To minimize the risk of regrets in women contemplating CPM, it is imperative that these women be counseled regarding an estimation of contralateral breast cancer risk, the alternatives to CPM, and the efficacy of CPM. In addition, these women should have realistic expectations of the cosmetic outcomes of surgery and understand the potential impact on their body image.
Ultrastructural differences in efferent ducts and several regions of the epididymis of the hamster

The ultrastructure of the hamster efferent ducts and epididymis was studied and the results were correlated with previously published data on the composition of luminal fluid obtained by micropuncture. Samples of the efferent ducts and parts of the epididymis designated initial segment, caput, corpus, proximal cauda, distal cauda, and “epididymal vas” were prepared. The efferent ducts contained principal cells characterized by a profusion of apical vesicles and numerous very large vacuoles that were distributed throughout the cytoplasm. Ciliated cells had few vesicles and vacuoles. Occasional cells contained many particles resembling glycogen. In the epididymis, the following trends were observed. The height of the epithelium and the size of the principal cells declined from initial segment to distal cauda. Apical vesicles and vacuoles with a light content were extremely numerous in principal cells of the initial segment and decreased progressively in the more distal regions. In the initial segment, basal and perinuclear rough endoplasmic reticulum was abundant and was distended with a material that resembled newly synthesized protein. Further distally in the epididymis cisternae of the rough endoplasmic reticulum were narrow and contained little intracisternal material. Light cells containing many vesicles, vacuoles, and lysosome-like structures were very prominent in the caudal segments. The epithelium of the epididymal vas had features intermediate between cauda epididymidis and ductus deferens. The cytoplasmic droplet in luminal sperm began to migrate caudally between the caput and corpus epididymidis and reached the posterior extremity of the middle piece in the distal cauda. Some degenerating sperm were observed in the lumen of the distal segments of the epididymis. The abundance of cytoplasmic vesicles and vacuoles in principal cells of the efferent ducts and initial segment of the epididymis correlated with the site of greatest fluid absorption as determined by micropuncture studies, suggesting that these structures are involved in absorption of fluid from the lumen. Between the caput and distal cauda epididymal segments, where absorption of sodium and potassium but not of fluid occurred, there were few vesicles and vacuoles in principal cells, but the “light” cells were large and numerous and contained many vacuoles. The principal cells of the initial segment were best equipped with rough endoplasmic reticulum to synthesize a protein.
Edge effects in computer models of spatial competition

Abstract Spatially explicit models of biological growth processes make assumptions about the interactions near the edges of the finite plots modeled. The most realistic approach is to embed the plot of interest in a larger space, but this is computationally costly and only moves the edge further away. To determine the bias introduced by using computationally efficient but less realistic methods, we used Monte Carlo simulation to compare four approaches to modeling the effects of boundaries on sessile organisms growing into asymmetric shapes under crowded conditions in finite regions. The four algorithms compared were: (a) embedding the modeled area in a space larger than the plot, (b) reflecting the area over the boundaries, (c) mapping the area onto a torus (translation), and (d) linearly expanding (extrapolating) the proportion of occupied area outside from that occupied inside. We studied the behavior of each algorithm in different ecological situations that varied the intensity of interactions and maximum sizes of individuals. Asymmetric growth due to interactions between individuals was modeled, and six different indices of individual size and shape were compared. When spatial interactions were intense, the embedded method was significantly different from other algorithms in almost all comparisons. Over all treatments and dependent variables, the torus was different from the embedded method in 18 of 30 comparisons. The reflection and linear expansion algorithms were approximately equal in their disagreement with the embedding space method: 28 and 27 comparisons, respectively, were different out of 30 comparisons. Dependent variables were ranked by the numerical differences between the embedding and non-embedding methods: measures of individual growth asymmetry produced the greate differences; measures of interactions between individuals produced intermediate differences; measures of individual size and percent cover were the least different. The relative numerical differences between the means of the variables produced by the non-embedding algorithms and the embedding method ranged from 60% to 0%, but 1 2 of these comparisons were within 5% of the embedding method estimates.
Fluorescence Lifetime Correlation Spectroscopic Study of Fluorophore-Labeled Silver Nanoparticles

In this paper, we introduce the use of fluorescence lifetime correlation spectroscopy to study the metal−-fluorophore interactions in solution at the single-fluorophore level. A single-stranded oligonucleotide was chemically bound to a 50-nm-diameter single silver particle, and a Cy5-labeled complementary single-stranded oligonucleotide was hybridized with the silver particle-bound oligonucleotide. The distance between the fluorophore and silver particle was maintained by a rigid hybridized DNA duplex of 8 nm in length. The single Cy5-DNA-Ag particles showed more than 10-fold increase in fluorescence intensity and a 5-fold decrease in emission lifetimes as compared with Cy5-DNA free molecules in the absence of metal. The decrease of lifetime for the Cy5-DNA-Ag particle allowed us to resolve the correlation functions of the two species based on the intensity decays. The increased brightness of the Cy5-DNA-Ag particle as compared to free Cy5-DNA resulted in an increased contribution of Cy5-DNA-Ag to the cor...
Activation of metabotropic glutamate (mGlu)2 receptors suppresses histamine release in limbic brain regions following acute ketamine challenge.

In the present study we demonstrated that ketamine, an NMDA antagonist and possible psychotomimetic, increases extracellular histamine (HA) in the rat brain. We then examined the ability of the group II mGlu receptor agonist LY379268 to modulate the ketamine evoked increases in HA release in three limbic brain regions. Ketamine (25 mg/kg) increased HA in the medial prefrontal cortex (mPFC), ventral hippocampus (vHipp) and the nucleus accumbens (NAc) shell. LY379268 administered alone was without effect on basal HA efflux in the mPFC or vHipp but modestly decreased HA efflux in the NAc shell. Administration of LY379268 (3 and 10 mg/kg) prior to ketamine significantly attenuated the HA response in the mPFC, vHipp and the NAc shell. The inhibitory effects of LY379268 in the mPFC were mimicked by the systemic administration of the mGlu2 receptor positive allosteric modulator CBiPES (60 mg/kg). Finally, local perfusion experiments revealed that the effects of LY379268 on ketamine evoked HA efflux appear to be mediated by mGlu2 receptors outside the PFC as the intra-mPFC perfusion of LY379268 (100 μM or 300 μM) failed to attenuate ketamine evoked increases in HA efflux. Together, these novel observations reveal an effect of ketamine on histaminergic transmission in limbic brain areas and provide further insight into the possible antipsychotic mechanism of action of mGlu2/3 receptor agonists.
Immunolocalization of Aromatase- and Androgen Receptor-Positive Neurons in the Goldfish Brain ☆

Full expression of testosterone (T) actions in the brain requires both direct binding to androgen receptors (AR) and in situ aromatization to estradiol (E2). To determine the cellular basis of constitutively high aromatase and AR binding activities in teleost fish brain, and the neuroanatomic location and spatial relations of cells of each type, an immunocytochemical mapping study of goldfish (Carassius auratus) brain was carried out using antibodies to human placental aromatase and human/rat AR peptide and the avidin-biotin-peroxidase technique. Both antibodies specifically labeled cells that were neuronal in appearance and were most numerous in reproductive control centers: medial and ventral telencephalon (TEL) and preoptic and hypothalamic periventricular nuclei. Additional populations of aromatase- and AR-labeled cells were present in the olfactory bulbs, central telencephalon, and stratum periventriculare of the optic tectum. Anti-aromatase, but not anti-AR, labeled fiber tracts and fibrous layers in visual and auditory pathways, and perikarya and processes of premotor neurons known to integrate sensory input (reticulospinal neurons, Mauthner cells). Anti-AR selectively labeled lateral TEL regions, the nucleus ventromedialis thalami, and discrete cell clusters in the medial tegmental nucleus. Aromatase-immunoreactivity (-ir) was primarily cytoplasmic, whereas AR-ir was primarily nuclear, but relative intensity of nuclear vs cytoplasmic labeling with each antibody differed by brain region. Aromatase- and AR-ir cells were not obviously more numerous in goldfish brain than previously seen in birds and mammals, suggesting that enhanced expression occurs on a per cell basis. We conclude that T exerts its actions coordinately via direct and indirect pathways in most brain regions but independently via AR- or aromatase-mediated mechanisms in selected areas. These studies point to a wide role for androgen in modulating primary sensory signals as well as in classical reproductive processes.
Latitudinal variation in the availability and use of dissolved organic nitrogen in Atlantic coast salt marshes

North American Atlantic salt marshes are generally considered to be nitrogen (N) limited systems, and plants within these marshes were historically thought to use only inorganic forms of N, such as NH4+. Recent research has suggested that Spartina alterniflora may take up some organic nitrogen compounds directly. To determine the availability of dissolved organic nitrogen (DON) to S. alterniflora in marshes along the North American Atlantic coast, porewater was sampled at eight field sites along the North American Atlantic Coast, ranging from Maine (44° N) to Florida (30° N). To determine if a latitudinal gradient existed in the assimilation of either DON or NH4+, replicated mesocosm experiments were conducted with S. alterniflora plants at three field sites (Massachusetts, Virginia, South Carolina), which represented three distinct ecotypes in the latitudinal range. To determine how microbial activity may influence DON availability, we also assessed rates of microbial activity. We found that porewater DO...