cssi/SciSciGPT-SciSciNet huggingface dataset:
Spike initiation and propagation in wide field transient amacrine cells of the salamander retina

Our results suggest that the prominent spike, commonly recorded in wide field amacrine cells, is actively propagated along its processes. Current was passed through a patch pipette at the soma to elicit spike activity in the cell. The field potentials accompanying this spike activity were then measured with an extracellular electrode positioned at different sites along the cell and its processes, which had been made visible with Lucifer yellow. Different extracellular waveforms were measured at the soma, stalk, and cell processes: A monophasic negative-going extracellular voltage waveform, typically found at the site of action potential initiation, was recorded along the stalk between the soma and the radial processes. A biphasic, positive- negative waveform, typically associated with the truncated propagation of an action potential, was measured at the soma. A triphasic, positive- negative-positive extracellular waveform, typically associated with a fully propagated action potential, was recorded along the peripheral processes. The time to peak of this triphasic waveform increased with distance from the soma such that the calculated propagation velocity ranged from 0.5 to 2.5 cm/sec. The membrane regions carrying potassium, sodium, and calcium currents were examined by depolarizing the soma and eliminating different ionic currents in the cell. With only sodium present, extracellular potentials were measured at the stalk and processes, but rarely at the soma. When only potassium was present, extracellular potentials were measured at the soma and processes, but not the stalk. When only calcium channels carried the membrane current, extracellular potentials were measured only at the processes. The sites of different ligand-gated receptors were identified by puffing various transmitter substances at different positions radially along the processes and measuring their effects at the soma. In all cells tested, glutamate puffs elicited currents only when applied at processes within 200 microns of the soma. In some cells, GABA and glycine elicited currents up to 300 microns from the soma. As a control for the measurement of electrotonic spread, potassium puffs elicited depolarizations along a broader region of the processes. These results suggest that the excitatory glutamate-elicited synaptic input to these cells is confined to a narrow area of the processes near the soma. The spike then appears to be initiated at the stalk and propagated along the processes. Calcium currents at these processes suggest the presence of possible transmitter release sites. Thus, each wide field amacrine cell seems to be functionally and concentrically polarized, receiving input centrally near the soma and broadcasting its output by propagating spikes along its extensive processes.
Feedback-free kaleidoscope of patterns from nanosecond laser irradiated nematic liquid crystals

Summary form only given. The present paper is, to our knowledge, the first account of hexagon pattern formation under nanosecond laser irradiation in a single laser beam and without any feedback involved. In our experiment, regular structures in beam cross-section changed spontaneously from pulse to pulse from fringes and stripes to multiple hexagons of various scales.
On-chip cache memory resilience

This paper investigates the system-level impact of soft errors occurring in cache memory and proposes a novel cache-memory design approach for improving the soft-error resilience. Radiation experiments are conducted to quantify the severity of errors attributed to transients occurring in a cache memory subsystem. Simulation-based fault injections are then conducted to determine major failure modes and to assess the cost/benefits in cache memory designs/configuration alternatives. The performance, reliability, and overhead for each design configuration, e.g., cache block-size and write policy, are studied. The results indicate that the performance enhancement approaches using large cache block-sizes can adversely affect the soft-error sensitivity of the system. Write-through cache design is more susceptible to incomplete/incorrect program termination, while write-back cache design is more prone to data corruptions. A resilient cache design scheme, selective set invalidation (SSI), that better scrubs the cache-memory errors is proposed and evaluated.
Construction of Nucleic Acid Programmable Protein Arrays (NAPPA) 1: Coating Glass Slides with Amino Silane

INTRODUCTIONFunctional proteomics enables protein activities to be studied in vitro using high-throughput (HT) methods. Protein microarrays are the method of choice because they display many proteins simultaneously and require only small reaction volumes to assess function. Protein microarrays are typically used to (1) measure the abundance of many different analytes in a sample or (2) study the functions or properties of many proteins spotted on the array. Target protein microarrays are usually generated by expressing, purifying, and spotting the proteins onto a solid surface at very close spatial density. An alternative approach is to translate the proteins in situ on the array surface. This approach, termed "Nucleic Acid Protein Programmable Array" (NAPPA), enables the simultaneous expression of proteins in microarray format without the need for individual protein purification. This method uses cell-free extracts that transcribe and translate DNA into proteins which are then captured in situ, thus converting cDNA copies of genes into the desired target proteins. Instead of printing proteins at each feature of the array, the cDNA molecules for the corresponding genes that produce desired proteins are affixed to the array. Chemical treatment of glass slides and DNA isolation can be performed in advance and stored. The plasmid DNA can then be printed to make NAPPA slides, which can be stored dry for use. For experiments, NAPPA slides are expressed followed by detection of proteins and DNA using antibodies and stains. This protocol describes the initial preparation of slides to be used in the method.
Prodomains of Transforming Growth Factor β (TGFβ) Superfamily Members Specify Different Functions EXTRACELLULAR MATRIX INTERACTIONS AND GROWTH FACTOR BIOAVAILABILITY

The specific functions of the prodomains of TGFβ superfamily members are largely unknown. Interactions are known between prodomains of TGFβ-1–3 and latent TGFβ-binding proteins and between prodomains of BMP-2, -4, -7, and -10 and GDF-5 and fibrillins, raising the possibility that latent TGFβ-binding proteins and fibrillins may mediate interactions with all other prodomains of this superfamily. This possibility is tested in this study. Results show that the prodomain of BMP-5 interacts with the N-terminal regions of fibrillin-1 and -2 in a site similar to the binding sites for other bone morphogenetic proteins. However, in contrast, the prodomain of GDF-8 (myostatin) interacts with the glycosaminoglycan side chains of perlecan. The binding site for the GDF-8 prodomain is likely the heparan sulfate chain present on perlecan domain V. These results support and extend the emerging concept that TGFβ superfamily prodomains target their growth factor dimers to extracellular matrix macromolecules. In addition, biochemical studies of prodomain·growth factor complexes were performed to identify inactive complexes. For some members of the superfamily, the prodomain is noncovalently associated with its growth factor dimer in an inactive complex; for others, the prodomain·growth factor complex is active, even though the prodomain is noncovalently associated with its growth factor dimer. Results show that the BMP-10 prodomain, in contrast to BMP-4, -5, and -7 prodomains, can inhibit the bioactivity of the BMP-10 growth factor and suggest that the BMP-10 complex is like TGFβ and GDF-8 complexes, which can be activated by cleavage of the associated prodomain.
Estimating the infectivity of HIV from partner studies

The main sources of data for estimating infectivity of the human immunodeficiency virus (HIV) come from studies of the susceptible partners of individuals known to be infected with HIV. Estimation of infectivity from these studies is complicated by limitations imposed by the sampling designs. This paper reviews three sampling schemes that have been used in partner studies and, for each, proposes methods for estimating various theoretic models for infectivity. The methods, as well as procedures for checking goodness-of-fit, are illustrated using data from a study by Peterman and colleagues.
The G-Protein−Coupled Receptor GPR40 Directly Mediates Long-Chain Fatty Acid−Induced Secretion of Cholecystokinin

Background & Aims Long-chain fatty acid receptors G-protein−coupled receptor 40 (GPR40) (FFAR1) and GPR120 have been implicated in the chemosensation of dietary fats. I cells in the intestine secrete cholecystokinin (CCK), a peptide hormone that stimulates digestion of fat and protein, but these cells are rare and hard to identify. We sought to determine whether dietary fat-induced secretion of CCK is directly mediated by GPR40 expressed on I cells. Methods We used fluorescence-activated cell sorting to isolate a pure population of I cells from duodenal mucosa in transgenic mice that expressed green fluorescent protein under the control of the CCK promoter (CCK−enhanced green fluorescent protein [eGFP] bacterial artificial chromosome mice). CCK-eGFP cells were evaluated for GPR40 expression by quantitative reverse transcription polymerase chain reaction and immunostaining. GPR40 −/− mice were bred with CCK-eGFP mice to evaluate functional relevance of GPR40 on long-chain fatty acid−stimulated increases in [Ca 2+ ]i and CCK secretion in isolated CCK-eGFP cells. Plasma levels of CCK after olive oil gavage were compared between GPR40 +/+ and GPR40 −/− mice. Results Cells that expressed eGFP also expressed GPR40; expression of GPR40 was 100-fold greater than that of cells that did not express eGFP. In vitro, linoleic, oleic, and linolenic acids increased [Ca 2+ ]i; linolenic acid increased CCK secretion by 53% in isolated GPR40 +/+ cells that expressed eGFP. In contrast, in GPR40 −/− that expressed eGFP, [Ca 2+ ]i response to linoleic acid was reduced by 50% and there was no significant CCK secretion in response to linolenic acid. In mice, olive oil gavage significantly increased plasma levels of CCK compared with pregavage levels: 5.7-fold in GPR40 +/+ mice and 3.1-fold in GPR40 −/− mice. Conclusions Long-chain fatty acid receptor GPR40 induces secretion of CCK by I cells in response to dietary fat.
Pickleworm: Mortality on Cucumbers in the Field

At Charleston, S. C. in 1978 and 1979 and at Blackville, S. C. in 1979, immature stages of the pickleworm (Diaphania nitidalis (Stoll) were collected on cucumber and densities were estimated. Populations were higher at Charleston than at Blackville. Egg parasitism by Trichogramma exiguum Pinto and Platner ranged from 0 to 69% at Charleston and appeared to be density dependent and limited to late in the season but was unrecorded at Blackville. Larval parasitism ( Apantales sp.) was low, ranging from 0 to 10%. Fire ants ( Solanopsis spp.) were an important predator of pupae.
Parallel Algorithms to Set Up the Benes Permutation Network

A parallel algorithm to determine the switch settings for a Benes permutation network is developed. This algorithm can determine the switch settings for an N input/output Benes network in 0(log2N) time when a fully interconnected parallel computer with N processing elements is used. The algorithm runs in 0(N½) time on an N½× N½mesh-connected computer and 0(log4N) time on both a cube connected and a perfect shuffle computer with N processing elements. It runs in 0(k log3N) time on cube connected and perfect shuffle computers with N1+1/kprocessing elements.
Response to Wilkinson and Schwartz on the epistemologies of adolescents.

Sumwry.-In their 1987 paper Wilkinson and Schwartz address the priority of chronologid age vs academic aptitude as determinants of cognitive complexity. This critique observes that the authors misrepresent their major reference and do not follow the precedent they cite for their methods. They then dichotomize their sample of gifted students into dualists and relativism by arbitrarily labeling the students' scores on an inappropriate measure. Contrary to their major premise, Perry never mentions chronological age and even offers data supportive of these authors' claims for aptimde. However, his model links students' cognitive growth primarily to their experience of diversity among authorities and peers. I am puzzled by this paper. The authors state their inrerest "in determining whether differences in students' epistemological beliefs could be accounted for by chronological age or mental aptitude." Since the authors put the study forward as "An Empirical Test of Perry's Model" and assume that Perry links movement from dualistic into relativistic thinking to chronological age, I have researched Perry's work, and I find that he never mentions "chronological age." He does trace a development year by year in his samples of college students but reveals its source, in students' reports, in the experience of diversity in and out of the classroom. The authors go so far as to assume "that Perry would predicr that dl (sic) students below the age of 15 would be dualists." For this key assumption the authors rely on Perrg's 1968 report that a mujordty of freshmen of 1954 thought dualistically; they do not note his statement available to them in their 1981 reference (p. 98) estimating that the modal freshman in his sample of 1970-71 was thinking relativistically. It seems unlikely that Perry would have been confused on such a matter since he had, as a teacher (personal communication), received a paper from a sixth grader analyzing Andrew Jackson's monemrg policy in the light of the economic theories (plural) of his pred
A Mixture-Model Based Algorithm for Real-Time Terrain Estimation

A real-time terrain mapping and estimation algorithm using Gaussian sum elevation densities to model terrain variations in a planar gridded elevation model is presented. A formal probabilistic analysis of each individual sensor measurement allows the modeling of multiple sources of error in a rigorous manner. Measurements are associated to multiple locations in the elevation model using a Gaussian sum conditional density to account for uncertainty in measured elevation as well as uncertainty in the in-plane location of the measurement. The approach is constructed such that terrain estimates and estimation error statistics can be constructed in real-time without maintaining a history of sensor measurements. The algorithm is validated experimentally on the 2005 Cornell University DARPA Grand Challenge ground vehicle, demonstrating accurate and computationally feasible elevation estimates on dense terrain models, as well as estimates of the errors in the terrain model.
Measurement of mechanical resonance and losses in nanometer scale silicon wires

We present data on nanofabricated suspended silicon wires driven at resonance. The wires are electrostatically driven and detected optically. We have observed wires with widths as small as 45 nm and resonant frequencies as high as 380 MHz. We see a strong dependence of the resonant quality factor on the surface to volume ratio.
Grasp Planning for a Two-Fingered Parallel-Jawed Gripper

The main emphasis of this paper is on grasp planning for a two-fingered parallel jawed gripper (typically used in industries) utilizing visual feedback for improved grasping for a planar object. Appropriate placement of fingers on the object plays an important role in grasp stability. This task is relatively easier for a priori-known target. But when the model of the object is not known a priori, it becomes difficult to plan the grasp and the usability of manipulator becomes limited. The main difficulty is in deciding upon the grasp points in a random object at a random location. A general approach has been presented in this paper which is applicable to any planar object. The approach uses the 2D features extracted from the image such as centroid, dimensions and principal axes to compute the grasp points' coordinates and the location of grasp axis for stability. A specialized approach is also presented which deals with objects containing only straight edges. The specialized approach utilizes Hough transform and image features in conjunction to enhance the performance of the algorithm. The proposed method can handle abrupt changes in the contour of an object as the algorithm takes object corners into account. Experiments were conducted in the laboratory to test the effectiveness of the proposed algorithm and validate the resuls.Copyright © 2006 by ASME
Anti-pneumolysin activity of commercially available α1-antitrypsin is due to cholesterol impurities

Pneumolysin (PLY), the principal cytolytic toxin of Streptococcus pneumoniae, may be important in the pathogenesis of acute lung injury during pneumococcal pneumonia. However, the local host defenses that limit PLY injury to lung tissues have not been characterized. We investigated the ability of a commercial preparation of alpha 1-antitrypsin (alpha 1-AT), a major plasma anti-proteinase, to inhibit PLY. At normal plasma concentrations, the alpha 1-AT preparation prevented PLY injury to bovine pulmonary artery endothelial cells, rat alveolar epithelial cells, and human erythrocytes. The alpha 1-AT preparation selectively inhibited thiol-activated bacterial toxins; it was inactive against snake venom hemolysins, mastoparan, and oxygen-stable bacterial toxins. Biochemical characterization of the alpha 1-AT preparation and comparison with other available alpha 1-AT preparations revealed that this inhibitory activity was due to contamination with nanomolar concentrations of cholesterol. Characterization of non-immune human plasma anti-pneumolysin activity showed that beta-lipoprotein fractions contain the major inhibitory activity. We caution other investigators that the inhibition of bacterial virulence by these alpha 1-AT preparations may indicate toxin-mediated, rather than protease-mediated, mechanisms.
The P3(00) wave of the averaged evoked potential: A bibliography

Stimulated by the potential value of a measure of central cortical processing, research on the P3(00) wave of the averaged evoked potential has flourished since the initial studies in the mid-1960s. A compilation of 145 references to articles on the P3(00) wave is listed. The criteria used in developing the bibliography were completeness, currency, and accessibility.
A simulation study to examine the sensitivity of the Pettitt test to detect abrupt changes in mean

AbstractThe Pettitt test is a non-parametric test that has been used in a number of hydroclimatological studies to detect abrupt changes in the mean of the distribution of the variable of interest. This test is based on the Mann-Whitney two-sample test (rank-based test), and allows the detection of a single shift at an unknown point in time. This test is often used to detect shifts in extremes because of the lack of distributional assumptions. However, the downside of not specifying a distribution is that the Pettitt test may be inefficient in detecting breaks when dealing with extremes. Here we adopt a Monte Carlo approach to examine the sensitivity of the Pettitt test in detecting shifts in the mean under different conditions (location of the break within the series, magnitude of the shift, record length, level of variability in the data, extreme vs non-extreme records, and pre-assigned significance level). These simulation results show that the sensitivity of this test in detecting abrupt changes incre...
Localization of receptors for bombesin-like peptides in the rat brain.

BN-like peptides and receptors are present in discrete areas of the mammalian brain. By radioimmunoassay, endogenous BN/GRP, neuromedin B, and ranatensin-like peptides are present in the rat brain. High-to-moderate concentrations of BN/GRP are present in the rat hypothalamus and thalamus, whereas moderate-to-high densities of neuromedin B and ranatensin-like peptides are present in the olfactory bulb and hippocampus, as well as in the hypothalamus and thalamus. While the distribution of neuromedin B and ranatensin-like peptides appears similar, it is distinct from that of BN/GRP. When released from CNS neurons, these peptides may interact with receptors for BN-like peptides. BN, GRP, ranatensin, and neuromedin B inhibit specific (/sup 125/I-Tyr4)BN binding with high affinity. By use of in vitro autoradiographic techniques to detect binding of (/sup 125/I-Tyr4)BN to receptors for BN-like peptides, high grain densities were found in the olfactory bulb and tubercle, the nucleus accumbens, the suprachiasmatic and paraventricular nucleus of the hypothalamus, the central medial and paraventricular thalamic nuclei, the hippocampus, the dentate gyrus, and the amygdala of the rat brain. Some of these receptors may be biologically active and mediate the biological effects of BN-like peptides. For example, when BN is directly injected into the nucleus accumbens, pronounced grooming resultsmore » and the effects caused by BN are reversed by spantide and (D-Phe12)BN. Thus, the putative BN receptor antagonists may serve as useful agents to investigate the biological significance of BN-like peptides in the CNS.« less
THE SCANDALOUS JOURNEY OF MONSIEUR J.: SAINT-ÉVREMOND'S ‘LETTRE A M.J.G.E.C.D.P.’

Un examen de cette Lettre, editee par Barbin en 1692 mais avec d'importantes modifications au dire de son auteur
The hierarchy problem in supersymmetric grand unified theories

Abstract Supersymmetric models are discussed with a view to solving the hierarchy problem in grand unified theories. Several types of light scalars are obtained and classified. A definition of naturalness is given for supersymmetric grand unified models, and a semi-realistic O(10) model is presented.
Diversity and the handicapped: an informal look.

Data for viewings of 58 television game shows suggests none of the 157 observed contestants to be physically handicapped.
Policy Changes in Medicare Home Health Care: Challenges to Providing Family-Centered, Community-Based Care for Older Adults.

The Balanced Budget Act of 1997 (BBA) established new reimbursement systems in the Medicare home health fee-for-service benefit. Reimbursements were reduced to 1993 levels and per-beneficiary capitated limits were introduced for the first time. This article analyzes the impact of these changes on chronically ill older adults and their families. The study combined a secondary analysis of the Provider of Service file (1996, 1999, 2002, and the Medicare Current Beneficiary Survey (1996, 1998) with qualitative interviews of home health agency directors. The greatest decreases in staff and visits were for medical social work and home health aide services. Patients with caregivers saw greater decreases in visits and reimbursements for all visits, skilled nursing, medical social work, and home health aide visits. Agency directors reported that they increased caregiver education, training, and involvement in care in order to discharge patients sooner. Additional research is needed to understand the long-term, adv...
Gradients of prorenin and active renin in ovarian venous and peripheral venous blood samples obtained simultaneously

Abstract Previous studies have demonstrated the presence of prorenin, active renin, and angiotensin II in human follicular fluid. The purpose of this study was to analyze prorenin, active renin, and ovarian steroids in ovarian venous blood and peripheral venous blood samples obtained simultaneously. We studied 10 premenopausal patients undergoing oophorectomy in various phases of the menstrual cycle. Prorenin levels in the ovarian venous effluent were more than twofold higher than levels in peripheral blood, 136.8 ± 34.1 versus 35.6 ± 8.3 ng angiotensin I per milliliter per hour ( p p = 0.07). Prorenin levels correlated with those of active renin in ovarian venous blood ( r = 0.76, p r = −0.73, p
Radiation enhancement of radiolabelled antibody deposition in tumors.

Abstract Recent clinical observations led to the use of external radiation to increase tumor targeting by radiolabelled I31-1 antiferritin. Examination of increased uptake of 131-1 labelled antiferritin following external radiation was carried out in syngeneic implanted hepatomas (H4IIE, 3924A, 7800, and 7777). Exposure to 10 Gy increased the tumor: liver uptake ratio from 1.55 to 1.86 for H4IIE; from 1.56 to 2.0 for 7800; from 1.34 to 1.97 for 7777; and from 1.05 to 1.19 for 3924A. The pattern of uptake varied among the different tumor types, reflecting their inherent differences in vascularity, tumor permeability, antigen density and growth rate, all of which influence antibody targeting of the tumors. When tumor and liver were irradiated, the tumor showed increased differential uptake of labelled antibody compared to normal liver. 51-Cr labelled erythrocytes were used to study the relative vascularity and blood pooling in H4IIE hepatoma and normal tissue. External radiation to the tumor did not increase the uptake of 51-Cr labelled erythrocytes in any site. These studies provide an insight into the role of external radiation as a modality that increases radiolabelled antibody targeting in hepatoma.
The case for adversarial yahad.

The words yahad and yahdāw regularly denote the relationship between opponents in physical warfare. Evidence from Hebrew and Akkadian shows that they have a similar function in descriptions of legal disputes, as well.
Effects of birth trauma and estrogen on urethral elastic fibers and elastin expression.

Objectives To investigate the effects of birth trauma and estrogen on urethral elastic fibers and elastin expression. Methods Pregnant rats were subjected to sham operation (Delivery-only), DVDO (delivery, vaginal distension and ovariectomy), or DVDO + E2 (estrogen). At 2, 4, 8, or 12 weeks, their urethras were harvested for elastic fiber staining and reverse transcription–polymerase chain reaction analysis. Urethral cells were treated with transforming growth factor– β1 (TGFβ1) and/or estrogen and analyzed for elastin mRNA expression. Urethral cells were also examined for the activities of Smad1- and Smad3/4-responsive elements in response to TGFβ1 and estrogen. Results At 8 weeks post-treatment, the urethras of DVDO rats had fewer and shorter elastic fibers when compared with Delivery-only rats, and those of DVDO + E2 rats had fewer and shorter elastic fibers when compared with DVDO rats. Elastin mRNA was expressed at low levels in Delivery-only rats and at increasingly higher levels in DVDO rats at 2, 4, and 8 weeks but at sharply lower levels in DVDO + E2 rats when compared with DVDO rats at 8 weeks. Urethral cells expressed increasingly higher levels of elastin mRNA in response to increasing concentrations of TGFβ1 up to 1 ng/mL. At this TGFβ1 concentration, urethral cells expressed significantly lower levels of elastin mRNA when treated with estrogen before or after TGFβ1 treatment. Both Smad1- and Smad3/4-responsive elements were activated by TGFβ1 and such activation was suppressed by estrogen. Conclusions Birth trauma appears to activate urethral elastin expression via TGFβ1 signaling. Estrogen interferes with this signaling, resulting in improper assembly of elastic fibers.
Characterization of rat skeletal muscle monoamine oxidase

Abstract Optimal conditions for deamination of 5-hydroxytryptamine in rat skeletal muscle were determined. The presence of monoamine oxidase (MAO) A and MAO B isozymes was demonstrated by the use of tyramine (a substrate of both forms), specific substrates (serotonin and benzylamine), and specific inhibitors (clorgyline and deprenyl) of MAO A and B respectively. A 6.5:3.5 ratio of MAO A to B was found using a whole muscle homogenate, while a 7.5:2.5 ratio was found with isolated mitochondria. Thermal inactivation studies demonstrated that skeletal muscle MAO A is more susceptible to heat inactivation than MAO B. The approximate proportion of muscle homogenate MAO which is present in sympathetic nerves was found to be 18 per cent, as determined by treating rats with 6-hydroxydopamine and quantifying the decrease in activity. Significant inhibition of MAO activity was observed after administration in vivo of the MAO inhibitors pargyline, tranylcypromine and harmaline.
Mechanics of the dynamic release process for stiction failed microcantilever beams using structural vibrations

Recently it has been shown that structural vibrations are an efficient means to repair stiction failed microcantilever beams. Experiments and analysis have identified excitation parameters (amplitude and frequency) that successfully initiated the debonding process between the microcantilever and the substrate. That analysis could not describe what happened after the debonding process was initiated. For example it could not predict if the beam would transition from a s-shaped to an arc-shaped configuration or even be repaired to a free-standing beam. The current research examines the post-initiation behavior of stiction failed microcantilever beams. A new-coupled fracture/vibration model is formulated and used to track the evolution of the repair in order to determine the extent of repair under various conditions. This model successfully explains phenomenological observations made during the experiments regarding the repair process being dependent on direction of frequency sweeps, complete and partial repair, and monitors the degree of repair no repair, partial repair or complete repair along with releases time associated with such repairs.
MRI abnormalities in Behr syndrome

The etiology of Behr syndrome remains uncertain. A 6-year-old girl with a progressive syndrome of optic atrophy, ataxia, myoclonic epilepsy, urinary incontinence, and pyramidal tract degeneration suggestive of Behr syndrome is described. Diffuse, symmetric white matter abnormalities were demonstrated by magnetic resonance imaging suggesting that Behr syndrome may represent a disorder of white matter associated with an unknown biochemical abnormality.
LXR: A nuclear receptor target for cardiovascular disease?

The liver X receptors (LXRs) are sterol-responsive transcription factors that regulate the expression of genes involved in cholesterol homeostasis. Studies in murine models have confirmed that LXR agonists exert antiatherogenic effects, perhaps by inducing efflux from lipid-loaded cells. Unfortunately, these compounds also increase hepatic and serum triglyceride levels. LXR agonists that exert desirable effects in macrophages without stimulating hepatic lipogenesis will probably be required before the LXR pathway can be exploited as a therapeutic target in cardiovascular disease.
ON MULTIPLE BROODS AND THE BREEDING STRATEGY OF ARCTIC SANDERLINGS

Summary. Sanderlings on Bathurst Island in the Canadian arctic have two patterns of incubation. At some nests the eggs are covered soon after the fourth egg has been laid and at others incubation is delayed for 5–6 days. Because the delay is about the same time required to lay a second clutch and because a single individual alone incubates at any one nest, we suspected that Sanderlings might normally lay two clutches in a season, the male caring for one brood and the female for the other. Histological and gross examination of the ovaries of two females taken as the birds began incubation showed eight freshly ovulated follicles in each female. The size gradation and histological appearance of the follicles indicated that two clutches of four eggs each had been laid within 8–10 days by a single female. The ovary of one female had additional large yolky follicles, suggesting a physiological capability of further ovulations. Field conditions in the arctic summer are highly variable, and the small eggs and the rapid sequence of broods of Sanderlings may be breeding adaptations that permit them to multiply the traditional wader clutch of four eggs by 2 or 3 in favourable years. Selection for mating systems characterised by brief pair bonds and by polyandry is expected in precocial birds where some broods are incubated and cared for by the male, but further field work is required to determine the precise mating system of Sanderlings.
The quasiparticle properties of UPt3 and the high-Tc cuprates

The dynamic fluctuations due to localized Hubbard type of effective interactions, U and J, are calculated perturbatively up to second order around the local density approximation (LDA) electronic structure. We have found for UX3 (X  Ir, Pt, or Au), the mass-enhancement factors are in good agreement with experiment for U = 2eV, and that the trends in the enhancement factors are systematically related to changes in the underlying LDA electronic structure. As for La2CuO4 we find that the dynamic fluctuations are small despite the large effective interaction. Further, our approach reproduces the insulating ground state and the magnetic moment correctly. For the doped case [La2-xBaxCuO4 (x ≠ 0)] we find that even though the mass enhancement is small, there is a significant broadening of the quasiparticles close to the Fermi energy.
Line-of-sight wave propagation through the turbulent atmosphere

A review of the recent developments in the field of random fluctuations of an electromagnetic wave propagated over a line-of-sight path is presented. The major interest is in the optical to millimeter wavelength range where fluctuations in amplitude, phase, and angle-of-arrival are important system considerations. It is assumed that the fluctuations are the result of variations in the refractive index caused by turbulence in the atmosphere. The review concentrates on the major approximations involved in the theoretical developments, and in particular, attempts to put in perspective the arguments over Rytov's method. The paper includes a number of previously untranslated results from the Russian literature, and some previously unpublished results of the author's. A brief assessment of new theoretical approaches and a discussion of some extremely important experimental work are given.
Necrosis as a Prognostic Factor in Glioblastoma Multiforme

BACKGROUND Many pathologists require the presence of tumor necrosis within an astrocytic neoplasm to establish the diagnosis of glioblastoma multiforme (GM). Two new grading systems for astrocytic neoplasms allow a tumor to be diagnosed at the highest level of anaplasia without requiring the presence of tumor necrosis. METHODS To determine whether GMs without necrosis had biologic behavior most compatible with a diagnosis of GM or of anaplastic astrocytoma (AA), we examined the survival of 299 patients whose tumors were diagnosed as GM because they contained endothelial proliferation and who were treated according to prospective clinical protocols. Multivariate proportional-hazards survival analysis was used to assess the importance of tumor necrosis after adjustment for other prognostic factors. RESULTS Of 275 patients with GMs containing endothelial proliferation, 88% had tumor necrosis. Absence of necrosis was associated with younger age and with less extensive surgical resection. The absence of necrosis predicted longer survival in univariate analysis (P = 0.02) and after adjustment for age, Karnofsky performance score, and extent of resection in a multivariate analysis (P = 0.04). However, the magnitude of the survival difference was not clinically important: patients without tumor necrosis had a median survival of 12.5 months, and those with tumor necrosis had a median survival of 10.9 months. Kaplan-Meier survival rates two years after diagnosis were 13.0% for patients with necrosis and 27.1% for patients without necrosis; the difference in 2-year survival was not statistically significant (difference in survival rates = 14.1%, 95% confidence interval −2.2% to 30.4%). CONCLUSIONS The survival of patients with astrocytic neoplasms containing endothelial proliferation and no necrosis conforms best to the pattern expected for patients with GM rather than AA. This supports the classification of these tumors as GM in the revised World Health Organization grading system and as grade 4 astrocytomas in the St. Anne-Mayo grading system. Cancer 1996;77:1161-6.
X-GTRBAC: an XML-based policy specification framework and architecture for enterprise-wide access control

Modern day enterprises exhibit a growing trend toward adoption of enterprise computing services for efficient resource utilization, scalability, and flexibility. These environments are characterized by heterogeneous, distributed computing systems exchanging enormous volumes of time-critical data with varying levels of access control in a dynamic business environment. The enterprises are thus faced with significant challenges as they endeavor to achieve their primary goals, and simultaneously ensure enterprise-wide secure interoperation among the various collaborating entities. Key among these challenges are providing effective mechanism for enforcement of enterprise policy across distributed domains, ensuring secure content-based access to enterprise resources at all user levels, and allowing the specification of temporal and nontemporal context conditions to support fine-grained dynamic access control. In this paper, we investigate these challenges, and present X-GTRBAC, an XML-based GTRBAC policy specification language and its implementation for enforcing enterprise-wide access control. Our specification language is based on the GTRBAC model that incorporates the content- and context-aware dynamic access control requirements of an enterprise. An X-GTRBAC system has been implemented as a Java application. We discuss the salient features of the specification language, and present the software architecture of our system. A comprehensive example is included to discuss and motivate the applicability of the X-GTRBAC framework to a generic enterprise environment. An application level interface for implementing the policy in the X-GTRBAC system is also provided to consolidate the ideas presented in the paper.
OCD with comorbid OCPD: a subtype of OCD?

Abstract Objective The current study examined the validity of using comorbid obsessive–compulsive personality disorder (OCPD) to identify a subtype of individuals with obsessive–compulsive disorder (OCD). Method Data for the current study were drawn from an ongoing, longitudinal study of the course of OCD and include intake assessments for 238 subjects with primary and current DSM-IV OCD who were treatment seeking. Results More than one fourth of the subjects ( N = 65, 27%) met criteria for comorbid OCPD. As compared to OCD − OCPD subjects, the OCD + OCPD subjects had a significantly younger age at onset of first OC symptoms ( p = 0.013), and a higher rate of symmetry and hoarding obsessions, and cleaning, ordering, repeating, and hoarding compulsions (all p ’s p = 0.007) and avoidant personality disorder ( p = 0.006). The OCD + OCPD subjects also had significantly lower ratings of global functioning ( p = 0.001) and more impaired social functioning ( p = 0.004), despite a lack of significant differences on overall severity of OCD symptoms. Conclusions Our findings indicate that individuals with both OCD and OCPD have distinct clinical characteristics in terms of age at onset of initial OC symptoms, the types of obsessions and compulsions they experience, and psychiatric comorbidity. Our findings, coupled with data from family studies showing a higher than expected frequency of OCPD in first degree relatives of OCD probands, suggest that OCD associated with OCPD may represent a specific subtype of OCD. Additional research is warranted to further establish the validity of this subtype.
Investigation of electrooptic modulator disruption by microwave-induced transients

This paper presents a detailed investigation of the physical mechanisms underlying the disruption of a lithium niobate electrooptic modulator by RF pulses. It is shown that short-term modulator disruption is a direct consequence of resistive heating within the metal conductor of the coplanar waveguide electrode, which leads to a thermo-optic optical phase shift in the waveguides of the modulator. Resistive heating is also shown to contribute to permanent modulator damage at higher RF power. These results indicate that short-term RF disruption, and possibly RF damage, can be mitigated through improved thermal management. They also predict that short-term photonic link disruption can be reduced, if not eliminated, by use of a phase modulated photonic link.
Laser start-up system for magnetic mirror fusion.

A CO2 laser system has been developed at the Lawrence Livermore Laboratory to provide hot start-up plasmas for magnetic mirror fusion experiments. It can irradiate a frozen ammonia pellet with a laser power density in excess of 1013 W/cm2 in a 50-nsec pulse. The system uses commercially available lasers. Optical components were fabricated both by direct machining and by standard techniques. The technologies used are directly applicable to reactor-scale systems.
Influences of boil-off on the behavior of a two-phase natural circulation loop

Abstract This experimental study investigates the thermal hydraulic behavior and boiling mechanisms present in a natural circulation loop experiencing boil-off. Extended duration tests with inventory loss were conducted to examine the transient behavior of a test loop under constant heat load. Five different stages of natural circulation flow were identified: single-phase heating, transitional nucleate boiling, hydrostatic head fluctuations, stable two-phase flow, and geysering. The water level in the storage tank was observed to play an important role in the stability of the system as it directly influences the hydrostatic pressures and, therefore local saturation temperatures. It would found that changes in inventory can shift the boiling boundary to different segments of the loop, whose geometry and orientation dictate the flow regime and ultimately the system behavior. With continued loss of inventory, a break in the loop occurs and induces flow stagnation with geysering in the heated region. Further operation results in severe degradation of heat removal, with a potential for burn out and possible structural damage. For safety-related applications, the venting of steam can extend the long-term cooling time window for heat removal and is of significant practical interest.
Chemotherapeutic potential of methotrexate peptides.

Abstract MTX peptides in which the amino acid was linked to the α-carboxyl group have been prepared and examined for cytotoxicity before and after treatment with proteolytic enzymes. The alanine, aspartic acid and arginine derivatives (MTX-ala, MTX-asp and MTX-arg) were synthesized by a regio-specific route, following the general procedures of Rosowsky and Montgomery. Each compound was obtained in good yield, and purity was established by TLC, HPLC, absorbance spectra and elemental analyses. The MTX peptides were not hydrolyzed by a variety of proteolytic enzymes (e.g., trypsin, plasmin, urokinase, aminopeptidase). Pancreatic carboxypeptidase A, however, hydrolyzed MTX-ala readily, MTX-asp slowly and MTX-arg not at all. The MTX-ala and, to a lesser extent, MTX-arg were substrates for pancreatic carboxypeptidase B. MTX-arg was also hydrolyzed by the endogenous carboxypeptidase N in human serum. The cytotoxicity of these MTX peptides toward L1210 cells was measured in a microculture assay system using a tetrazolium dye. MTX-ala was weakly cytotoxic ( ID 50 = 2.0 × 10 −6 m ) compared to MTX ( ID 50 = 2.4 × 10 −8 m ). When MTX-ala was tested in the presence of carboxypeptidase A, the ID50 value improved to 8.5 × 10 −8 m . MTX-arg gave an ID50 of 5.0 × 10 −8 m , which was not unexpected in view of its susceptibility to hydrolysis by the carboxypeptidase activity present in the fetal calf serum of the culture medium. Inclusion of carboxypeptidase B lowered the ID50 value to 2.5 × 10 −8 m . Possible clinical uses of MTX peptides are discussed.
Distinct Mechanisms Mediate the Initial and Sustained Phases of Integrin-mediated Activation of the Raf/MEK/Mitogen-activated Protein Kinase Cascade *

Integrin-mediated adhesion to the extracellular matrix activates the canonical mitogen-activated protein kinase cascade, although the exact mechanism is not fully resolved. We show that integrin-mediated activation of Raf-1, an upstream regulator of mitogen-activated protein kinase, occurs in two phases. Efficient early activation of Raf required Raf-Ras interaction but was not affected by protein kinase C (PKC) inhibitors, while a lower, sustained level of activity was independent of Raf-Ras interaction but was reduced by PKC inhibitors. The combination of PKC inhibition and lack of Ras binding completely blocked integrin-mediated Raf activity. The activity of a membrane-bound Raf mutant that is deficient in Ras binding (Raf-R89L-CAAX) was also regulated by adhesion. Raf-R89L-CAAX activity was low in nonadherent cells, was rapidly stimulated to wild-type levels by cell adhesion, and remained at nearly maximal levels longer than wild-type activity. The activation of wild-type and mutant Raf proteins was ablated by cytochalasin D, demonstrating that cytoskeletal organization is required for activation of Raf, even when targeted to the membrane. These data suggest distinct initial and sustained phases of integrin-mediated Raf activation that require Raf membrane localization and possibly PKC activity, respectively, and that integrin-mediated adhesion may regulate a cytoskeleton-associated factor(s) responsible for Raf activation.
Satellite Laser Ranging: Current Status and Future Prospects

This paper is intended to be a nonmathematical tutorial on the subject of satellite laser ranging (SLR) with an emphasis on the characteristics and capabilities of present and future field-hardware and operational methods. Following a brief introduction to the basic concept of SLR and the many science applications of both satellite and lunar laser ranging, we discuss the developmental history of each of the major components which make up the ranging machine, i.e., the laser transmitter, photomultiplier, discriminator, and time interval unit. At the same time, we attempt to identify the sources of range error in each of the devices and present, whenever possible, experimental data which quantifies the magnitude of these errors. We also describe some of the subtleties associated with the operation of these devices in the field. Following the discussions on hardware and system calibration techniques, we briefly describe some error sources external to the basic ranging machine, but highly relevant to SLR, which are introduced by the target, atmospheric channel, ground surveys, epoch timekeeping, geopotential models, and numerical propagation errors. We summarize the description of modern day hardware with samples of actual satellite data, obtained as early as 1981, which show orbital fits with a 1.5 cm single shot rms and normal point rms of less than 3 mm with only 1-6 percent data editing. We conclude the paper with a discussion of ongoing research to develop systems potentially capable of millimeter absolute accuracies over satellite distances.