cssi/SciSciGPT-SciSciNet huggingface dataset:
Detection of Phosphatidylcholine-Coated Gold Nanoparticles in Orthotopic Pancreatic Adenocarcinoma using Hyperspectral Imaging

Nanoparticle uptake and distribution to solid tumors are limited by reticuloendothelial system systemic filtering and transport limitations induced by irregular intra-tumoral vascularization. Although vascular enhanced permeability and retention can aid targeting, high interstitial fluid pressure and dense extracellular matrix may hinder local penetration. Extravascular diffusivity depends upon nanoparticle size, surface modifications, and tissue vascularization. Gold nanoparticles functionalized with biologically-compatible layers may achieve improved uptake and distribution while enabling cytotoxicity through synergistic combination of chemotherapy and thermal ablation. Evaluation of nanoparticle uptake in vivo remains difficult, as detection methods are limited. We employ hyperspectral imaging of histology sections to analyze uptake and distribution of phosphatidylcholine-coated citrate gold nanoparticles (CGN) and silica-gold nanoshells (SGN) after tail-vein injection in mice bearing orthotopic pancreatic adenocarcinoma. For CGN, the liver and tumor showed 26.5±8.2 and 23.3±4.1 particles/100μm2 within 10μm from the nearest source and few nanoparticles beyond 50μm, respectively. The spleen had 35.5±9.3 particles/100μm2 within 10μm with penetration also limited to 50μm. For SGN, the liver showed 31.1±4.1 particles/100μm2 within 10μm of the nearest source with penetration hindered beyond 30μm. The spleen and tumor showed uptake of 22.1±6.2 and 15.8±6.1 particles/100μm2 within 10μm, respectively, with penetration similarly hindered. CGH average concentration (nanoparticles/μm2) was 1.09±0.14 in the liver, 0.74±0.12 in the spleen, and 0.43±0.07 in the tumor. SGN average concentration (nanoparticles/μm2) was 0.43±0.07 in the liver, 0.30±0.06 in the spleen, and 0.20±0.04 in the tumor. Hyperspectral imaging of histology sections enables analysis of phosphatidylcholine-coated gold-based nanoparticles in pancreatic tumors with the goal to improve nanotherapeutic efficacy.
Review Of Inequality Metrics With Application In Income Inequality In Louisiana

Economic data sets usually are, by their nature, very large and therefore researchers naturally want to analyze the distribution of the data set and make statistical inference about various parameters of interest, such as means, medians, variances, etc. To perform such tasks several incomes metrics or indices are generally used. Among the metrics widely used, we will consider in this paper only three: Lorenz curve, the the so-called S-Gini index and the Atkinson index. We also consider a general index of economic inequality that covers a number of indices, including the aforementioned S-Gini and Atkinson indices.
Must Virtue Be Taught

Wittgenstein S stories using mathematical imagery-about the group o f wood sellers, and others about people “measuring” with lax rulers, making unsystematic lists, not caring whether they are cheated or not, “calculating” by asking someone to let a number come to mindread, From a step away, as though their characters are children. It is appropriate, in writing so fundamentally about instruction, and in which a central character is the child, that we haue dramatized for us the fact that we begin our liues as children. Those tribes o f big children can put us in mind o f how little in each o f us gets educated; and make us wonder how we euer haue Fresh recruits for our culture. -Stanley L. Cauell‘
Leadership and Inclusion: Reculturing for Reform.

It [inclusion] probably has some merit to it. If I were a parent, I certainly would be an advocate for it. On the other hand, as a regular ed teacher, I wouldn't get too excited about it&. For the ...
Regulation of the gal operon of Escherichia coli by the capR gene.

Abstract We have examined in greater detail the derepression of uridine diphosphate galactose-4-epimerase synthesis in capR mutants of Escherichia coli first observed by Markovitz. (Markovitz, A. (1964) Proc. Nat. Acad. Sci. U. S. A. 51, 239–246). All three enzymes of the gal operon are derepressed from 2- to 4-fold by this mutation. This derepression may be superimposed on the conventional derepression seen when the gal operon is induced with fucose or by a regulatory mutation. Measurement of the level of gal messenger ribonucleic acid indicates that the derepression caused by the capR mutation probably occurs at the level of transcription since there is a coordinate increase in gal enzyme activity and in the level of gal mRNA. The effect of the capR mutation on the gal operon appears to be independent of cyclic 3',5'-monophosphate or glucose-mediated repression. Thus the product of the capR locus behaves as if it is an additional negative control element affecting the expression of the gal operon.
Gangs, Sociology of

Beginning with Frederic Thrasher's classic, The Gang: A Study of 1,313 Gangs in Chicago (1927), gangs have been a subject of continuous sociological scrutiny, law enforcement attention, and public interest. Although the term has been applied to groups of adult criminals, especially those that control segments of organized and professional crime, the preponderance of scholarly attention has focused on youth gangs. Yet scholars and law enforcement agencies disagree among and between themselves as to the definition of what kinds of groups constitute youth gangs. This article defines youth gangs as groups of youth that are unsupervised by adults and self-determining with respect to membership criteria, group structure, and behavior. The article traces changes and continuities in processes associated with gang formation and their behavior. Study of gangs provides opportunities for the observation and understanding of broader principles of human behavior, including the forms and the roles of youth culture.
Direct Relationship between Magnetism and MnO 6 Distortions in La 1 − x Ca x MnO 3

Measured distortions of the $\mathrm{Mn}\ensuremath{-}\mathrm{O}$ bond length distribution from x-ray-absorption fine-structure measurements are found to relate linearly to the doped hole concentration $x$ at room temperature in ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$. Comparison of the distortions above and below ${T}_{c}$ for colossal magnetoresistor (CMR) samples gives an estimate of the number of delocalized holes ${n}_{\mathrm{dh}}$, and we find that $\mathrm{ln}({n}_{\mathrm{dh}})\ensuremath{\propto}M$ (magnetization). These results are complementary to resistance measurements that show that $\mathrm{ln}(\ensuremath{\rho})\ensuremath{\propto}\ensuremath{-}M$. We have thus established the functional relationship between the electronic, spin, and lattice degrees of freedom in the CMR perovskites.
Rigorous calculations of permeation in mixed-matrix membranes: Evaluation of interfacial equilibrium effects and permeability-based models

Abstract We present rigorous calculations of single-component permeation in mixed-matrix membranes (MMMs), and show their importance in developing a more reliable understanding of MMM permeation behavior. We first develop methods for the construction of detailed and large-scale 3D mixed-matrix membrane (MMM) models, which are then solved by finite-element methods. Our models explicitly account for the effects of matrix-filler interfacial equilibrium in addition to the differences in Fickian diffusivity between the two phases. Analytical equations ( e.g ., Maxwell model) can only predict the MMM permeability under an implicit assumption that the interfacial equilibrium constant K and the diffusivity ratio of the filler and the matrix ( D f / D m ) can be lumped into a single parameter, the permeability ratio P f / P m = KD f / D m . It is shown here that the individual values of K and D f / D m , and not the combined permeability ratio P f / P m , determine the MMM permeability. Our simulations also indicate that an ideal MMM shows no significant direct effect of filler particle size. We fit our computational data to an empirical correlation that can be easily and accurately used to calculate ideal MMM permeabilities, given equilibrium and diffusion data for the matrix and filler. We also examine some current issues regarding interpretation of MMM permeation behavior. For example, CO 2 solubilities and diffusivities in representative MOF filler and polymer matrix materials are used to rigorously compare the ‘exact’ predictions with permeability-based models. The rigorous calculations show non-monotonic behavior of the MMM permeability as a function of the matrix permeability, which cannot be predicted by permeability-based models. Also, the ‘apparent’ CO 2 permeability of ZIF-8 fillers extracted with Maxwell and Lewis–Nielsen models from the computational MMM permeation data, varies by 3 orders of magnitude depending upon the matrix polymer. Though the ZIF-8 filler maintains a constant permeability of ~3000 Barrer, the permeability models would require postulation of (spurious) non-idealities such as matrix-dependent filler behavior or interfacial rigidification to explain the results. Overall, this work provides a method for more reliable use of models to understand and design MMMs, as well as to better interpret the large and growing body of experimental data on these membranes.
Photochemical Transformation of Dissolved Organic Carbon in Lake Superior—An In-situ Experiment

A direct solar irradiation experiment was conducted for Lake Superior water (initial [DOC] = 2.49 mgC/L) and Sturgeon River water (initial [DOC] = 33.95 mgC/L) in Lake Superior on 22–23 August 1999. Water samples were sealed in quartz tubes and suspended in the lake at 0 m, 6 m, and 24 m. Samples were collected after 5.5 h and 15.5 h of exposure to sunlight. The dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) concentrations, UV-vis absorbance, and 3D fluorescence were measured on all samples. For irradiated lake water, DIC was photoproduced at a rate of 1.3 to 5.6 M DIC hr−1 for the first day and 1.3 to 2.1 × 102 nM DIC hr−1 for the second day, normalized to 1 mg DOC/L, and long wavelength absorbance decreased as a function of irradiation time. For both river and lake samples, integral fluorescence also decreased systematically and the fluorescence quantum yield decreased after photoirradiation. In addition, new fluorescence peaks at short wavelengths appeared in irradiated lake samples, suggesting the formation of new chromophores. After irradiation, DOC concentrations in surface samples were lower than those in deep samples. Rate constants for all processes measured decreased during the irradiation time. Rate constants for loss of fluorophores were greater than those for chromophores, which, in turn, were greater than the rate constants for loss of DOC.
A histochemical study of DPN-diaphorase in human white matter with some notes on myelination.

THERE is some indication of differences in the anatomical and chemical organization of individual fibre tracts in the brain, such as the outstanding activity of alkaline phosphatase in the retroflex bundle of the guinea pig (SHIMIZU, 1950) and the different rates of synthesis of acetylcholine in various fibre tracts (FELDBERG and VOGT, 1948). This paper reports on the distribution of DPN-diaphorase in human white matter. The distribution of enzyme activity in human grey matter will not be touched upon. It resembles, in principle, that of succinic dehydrogenase in the guinea pig brain which, in turn, is similar to that of several oxidative enzymes in cat brain as documented recently in an histochemical atlas (FRIEDE, 1961). The activity of oxidative enzymes is much less in white matter than in grey matter, as shown by both biochemical and histochemical data. Histochemical studies revealed detailed differences in the cytological enzyme distribution in the various tracts. Some data on myelination and on certain features of enzyme transport in axons were included in this study because they imply a difference in the chemical organization of the tracts.
Preparation and controlled self-assembly of Janus magnetic nanoparticles.

Janus magnetic nanoparticles (∼20 nm) were prepared by grafting either polystyrene sodium sulfonate (PSSNa) or polydimethylamino ethylmethacrylate (PDMAEMA) to the exposed surfaces of negatively charged poly(acrylic acid) (PAA)-coated magnetite nanoparticles adsorbed onto positively charged silica beads. Individually dispersed Janus nanoparticles were obtained by repulsion from the beads on reversal of the silica surface charge when the solution pH was increased. Controlled aggregation of the Janus nanoparticles was observed at low pH values, with the formation of stable clusters of approximately 2−4 times the initial size of the particles. Cluster formation was reversed, and individually dispersed nanoparticles recovered, by restoring the pH to high values. At intermediate pH values, PSSNa Janus nanoparticles showed moderate clustering, while PDMAEMA Janus nanoparticles aggregated uncontrollably due to dipolar interactions. The size of the stable clusters could be controlled by increasing the molecular w...
Energy-efficient In-network encryption/decryption for wireless body area sensor networks

Advances in wearable devices and pervasive computing provide unprecedented opportunity for ubiquitous realtime e-Healthcare and patient monitoring by placing wirelessly connected sensors in, on, and around the body of patients. Due to the privacy-sensitive and mission-critical nature of these wireless body area sensor networks (WBASNs), as well as the desire to use them for long-time uninterrupted monitoring of patients' vital physiological signals, the privacy/security and energy efficiency of WBASNs are of primary concerns. In this paper, we propose a novel In-network AES Equivalent (IAE) mechanism to protect the security/privacy and maintain good energy efficiency for WBASNs at the same time. IAE achieves this goal by outsourcing part of the energy-consuming cryptographic operation to other deliberately-selected peer sensor nodes so as to balance the energy consumption of the entire network. An analytical model is proposed to characterize the computation and communication energy consumption of IAE, based on which we optimize the outsourcing under given security constraints. Through extensive simulations, we verify the effectiveness and efficiency of the proposed mechanism in prolonging the network lifetime under given security requirements.
The Effects of Musical Discrimination Training in Beginning Instrumental Music Classes

The purpose of this study was to determine whether beginning instrumental music students who receive musical discrimination training that incorporates models/discriminator foils and modeling/imitation demonstrate higher levels of musical discrimination skill or instrumental music performance achievement than do students who do not receive this training. The author randomly assigned 43 fifth-grade beginning instrumental music students to experimental and control groups for 18 weeks. The experimental group underwent a tape-recorded discrimination training program that included (a) identification of aural music phenomena through use of models and discriminator foils (a variant of the model, differing in a single musical element), (b) discrimination exercises, and (c) student imitation of models. The findings of this study suggest that beginning instrumental music students can develop musical discrimination skills with systematic training procedures that incorporate models and discriminator foils as well as modeling and imitation.
Determination of Trace Elements in Samples by Nuclear Scattering and Reaction Techniques

The feasibility of using low energy (15-25 MeV) ?-particle scattering for detecting traces of heavy elements in a bulk of light elements as, for example, in biological and environmental matter is explored. These measurements can provide information on all the elements in the sample simultaneously. Heavy elements require good energy resolution (~10 keV) for definite identification while light elements can be identified even with very poor energy resolution (?100 keV). Results of some measurements on a fish sample are presented. Similarly sub-Coulomb (p,?) reactions are explored for measuring traces of very light elements in a bulk of heavy elements. Suitable choice of bombarding energy almost completely suppresses the contribution from the heavy element. Results of a measurement in a very pure Zr sample are presented.
Environmental and farm commodity policy linkages in the US and the EC

This paper analyzes restrictions on agricultural chemicals in the United States and the EC under various farm commodity policy scenarios using a partial equilibrium simulation model. The model has three regions (United States, EC, rest of the world) and four commodities (wheat, maize, coarse grains, soybeans). Medium- and long-run impacts are derived. Given existing farm programs, U.S. landowners gain from chemical restrictions while EC landowners generally lose. Given bilateral elimination of farm programs, both U.S. and EC landowners gain from chemical restrictions. Bilateral farm program elimination without chemical restrictions induces a shift in chemical usage from the EC to the United States. Copyright 1992 by Oxford University Press.
State of the Art in Imaging and Chemoprevention for High-Risk Patients

Recent developments in breast imaging technology and chemoprevention clinical trials have provided promising new options for patients at increased risk of breast cancer. Yet there remains much debate and confusion among providers, patients, and insurers regarding accurate breast cancer risk assessment, appropriate breast cancer screening, and options for breast cancer prevention. We review the most recent literature on these topics in order to provide practicing clinicians with current, practical updates on breast cancer prevention and early detection for women at increased risk of breast cancer.
Influence of Age and Dietary Protein on Certain Free Amino Acids in Chick Blood Plasma

Abstract DURING the past few years, there has been a great deal of interest in studying the relationship of dietary amino acid levels to the concentrations of free amino acids in the blood plasma. Richardson et al. (1953) demonstrated that the concentrations of the free amino acids in chick plasma were related to the level of the same amino acids in the diet. In an experiment conducted to determine the rate and extent of absorption of amino acids from the intestinal tract of dogs, Denton and Elvehjem (1954) reported that the concentrations of amino acids in the blood corresponded roughly to the amino acid composition of the protein fed. Recently, Tonkinson et al. (1961) have presented data suggesting a correlation of the free amino acids in the blood plasma with the dietary amino acid requirements for turkeys. Since the blood serves as the primary means of transport of constituents to the …
Behavior analysis, program development, and transfer of control in the treatment of self-injury☆

This case study illustrates an empirical approach to the diagnosis, treatment, and controlled follow-up of self-injurious clients. Following an assessment period, during which environmental factors associated with a severely retarded adolescent's self-injury were identified, the contingent application of protective equipment was combined with a differential reinforcement procedure (DRO) and implemented in a multiple baseline design across two hospital settings. Results showed a marked decrease in the rate of self-injury. Upon discharge from the hospital, the program was successfully replicated at the adolescent's residential center, again using a multiple baseline design across settings.
An individual-based, spatially-explicit simulation model of the population dynamics of the endangered red-cockaded woodpecker, Picoides borealis

Spatially-explicit population models allow a link between demography and the landscape. We developed a spatially-explicit simulation model for the red-cockaded woodpecker, Picoides borealis, an endangered and territorial cooperative breeder endemic to the southeastern United States. This kind of model is especially appropriate for this species because it can incorporate the spatial constraints on dispersal of helpers, and because territory locations are predictable. The model combines demographic data from a long-term study with a description of the spatial location of territories. Sensitivity analysis of demographic parameters revealed that population stability was most sensitive to changes in female breeder mortality, mortality of female dispersers and the number of fledglings produced per brood. Population behavior was insensitive to initial stage distribution; reducing the initial number of birds by one-half had a negligible effect. Most importantly, we found that the spatial distribution of territories had as strong an effect on response to demographic stochasticity as territory number. Populations were stable when territories were highly aggregated, with as few as 49 territories. When territories were highly dispersed, more than 169 territories were required to achieve stability. Model results indicate the importance of considering the spatial distribution of territories in management plans, and suggest that this approach is worthy of further development.
Pleural empyema in children.

n the late 1950’s a tremendous increase in the incidence of staphylococcal pneumonia and empyema occurred throughout many of the I pediatric centers in the country. This increase was thought to have been caused by the emergence of antibiotic-resistant strains of bacteria [3]. Several papers appeared in the literature reflecting this changing pattern [4, 6, 71, and some strict rules for surgical management were advised in order to decrease mortality in this disease [6]. Formerly, this mortality ranged from a high of 100% in some series [l] to about 25% in other centers [5, 61. The generally accepted surgical routine was to insert a chest tube in all children who exhibited pleural fluid containing gram-positive cocci. This was followed frequently by conversion to open drainage with or without rib resection, and finally decortication if there was no definite improvement in two or three weeks and a captive lung was assumed to be present. Strict adherence to these principles brought the mortality down to around 10 or 12% [6]. Since about 1962, pleural empyema in children, particularly that due to staphylococci, has become less virulent, probably entirely as the result of newer antibiotic agents. Now certain transgressions can be taken from the older rules of management in order to shorten the hospital stay and decrease the discomfort of these children. It is the purpose of this paper to review the experience with all children diagnosed as having primary pneumonia and secondary empyema over the past 20 years at the Children’s Hospital of Los Angeles, in order to compare present-day management with that practiced 10 years ago.
Electronically tunable silicon photonic delay lines

Electronically tunable optical true-time delay lines are proposed. The devices utilize the combination of apodised gratings and the free-carrier plasma effect to tune the enhanced delay of silicon waveguides at a fixed wavelength. Three variations of the proposed scheme are studied and compared. The compact and integrable devices can achieve tuning ranges as high as ~660 ps with a loss of < 2.2 dB when operated in the reflection mode of the gratings. A delay of ~40 ps with a loss of < 10 dB and an estimated operation bit rate of ~20 Gb/s can be achieved.
Conditioned saccharin taste aversion induced by mycotoxins in rats: Lack of effect of ochratoxin A

The present study examined the putative aversive action of ochratoxin A (OA) using a conditioned saccharin aversion paradigm. Adult male rats consumed a 0.1% saccharin solution then were treated (IP) with either a 5% NaHCO3 vehicle (negative control), 32 mg/kg LiCl (positive control) or 0.75, 1.5 or 3.0 mg/kg OA. Twenty-four hours later, the rats were given a choice between tap water and the 0.1% saccharin solution. Rats treated with the vehicle or any of the doses of OA exhibited a marked preference for the saccharin solution, whereas the rats treated with LiCl exhibited a marked rejection of the saccharin solution. The implications of these data for an understanding of mycotoxicosis are discussed.
Developmental changes in brain indoles, serum tryptophan and other serum neutral amino acids in the rat

Abstract The rates at which brain neurons synthesize and release serotonin depend in part on brain tryptophan concentrations; these, in turn, vary directly with serum (or plasma) tryptophan, and inversely with the serum concentrations of other large neutral amino acids (LNAA). Concentrations of serum tryptophan, LNAA and brain indoles were examined in samples drawn at noontime from rats aged 0–59 days. Developmental changes in serum tryptophan largely paralleled those in the tryptophan/LNAA ratio, and brain tryptophan concentrations. Brain serotonin and 5-hydroxyindole acetic acid (5-HIAA) levels also increased postnatally; the changes in 5-HIAA tended to parallel those in brain tryptophan while those in serotonin did not.
Measurement of a solid-state triple point at the metal-insulator transition in VO2

The precise location of a solid-state triple point, at which three solid phases coexist in thermal equilibrium, has been determined by controlling the stress and temperature in a nanobeam of vanadium dioxide near its metal–insulator transition. Vanadium dioxide (VO2) is of interest in ultrafast optical and electrical switching applications thanks to the material's unique phase transition between metallic and insulating states involving several competing phases. This study of single-crystal VO2 nanobeams in a system in which the metal–insulator transition is finely controlled by adjusting temperature and strain pinpoints the previously elusive 'triple point' — the transition temperature at which one metallic and two insulating phases can coexist — as 65 °C. Other so-called correlated materials, including manganites and pnictides, also have poorly understood strain-critical phase transitions involving multiple components, and this work demonstrates a method that should be widely applicable in such situations. First-order phase transitions in solids are notoriously challenging to study. The combination of change in unit cell shape, long range of elastic distortion and flow of latent heat leads to large energy barriers resulting in domain structure, hysteresis and cracking. The situation is worse near a triple point, where more than two phases are involved. The well-known metal–insulator transition in vanadium dioxide1, a popular candidate for ultrafast optical and electrical switching applications, is a case in point. Even though VO2 is one of the simplest strongly correlated materials, experimental difficulties posed by the first-order nature of the metal–insulator transition as well as the involvement of at least two competing insulating phases have led to persistent controversy about its nature1,2,3,4. Here we show that studying single-crystal VO2 nanobeams5,6,7,8,9,10,11,12,13,14,15,16 in a purpose-built nanomechanical strain apparatus allows investigation of this prototypical phase transition with unprecedented control and precision. Our results include the striking finding that the triple point of the metallic phase and two insulating phases is at the transition temperature, Ttr = Tc, which we determine to be 65.0 ± 0.1 °C. The findings have profound implications for the mechanism of the metal–insulator transition in VO2, but they also demonstrate the importance of this approach for mastering phase transitions in many other strongly correlated materials, such as manganites17 and iron-based superconductors18.
IQGAP1 binds Rap1 and modulates its activity

IQGAP1 is a scaffolding protein involved in multiple fundamental cellular activities, including transcription, cell-cell attachment, and regulation of the cytoskeleton. To function in these pathways, IQGAP1 associates with numerous proteins such as actin, calmodulin, E-cadherin, β-catenin, CLIP-170, and components of the mitogen-activated protein kinase pathway. Moreover, IQGAP1 binds to active Cdc42 and Rac1 but not RhoA or Ras. Here we show that IQGAP1 also binds to the small GTPase Rap1. In vitro analysis demonstrates a direct interaction between Rap1 and IQGAP1, which is augmented by activation (GTP loading) of Rap1. Cdc42 does not modulate the interaction between Rap1 and IQGAP1. In contrast, the association is eliminated by calmodulin both in the absence and presence of Ca2+. The binding of Rap1 to a point mutant IQGAP1 construct that is unable to interact with calmodulin is 2.5-fold more than to wild type IQGAP1. Consistent with these findings, Rap1 binds to the IQ region of IQGAP1. Confocal microscopy demonstrates that Rap1 and IQGAP1 co-localize at the periphery of human epithelial cells but not in the cytoplasm. The interaction has functional sequelae. Overexpression of IQGAP1 substantially reduces adhesion-mediated activation of Rap1. In addition, Rap1 activation by cAMP is attenuated in cells that overexpress IQGAP1 and enhanced in cells lacking IQGAP1. These findings reveal that the interaction of IQGAP1 with Rap1 differs in several respects from its interaction with other small GTPases. Furthermore, our data suggest that IQGAP1 may link the calmodulin and Rap1 signaling pathways.
Estimation of left ventricular systolic function by nonvolumetric echocardiographic analysis in subjects with poor left ventricular visualization: a pilot study.

Background: Accurate assessment of left ventricular (LV) systolic function is an essential requirement in clinical cardiology. Several echocardiographic methods provide quantitative analysis of LV volumes and ejection fraction (EF) based on the precise tracing of endocardial borders. Often, however, technically limited studies prohibit such direct analysis, and alternative techniques must be applied. Hypothesis: Nonvolumetric echocardiographic methods which do not require endocardial edge definition and tracing may accurately provide quantitative LV systolic function data. Methods: A pilot study was conducted to validate and compare two recently described indirect echocardiographic methods of LV systolic function analysis, with LVEF by radionu-clear cardiac angiography (RNCA). Thirty-two consecutive patients undergoing RNCA for clinical indications also underwent echocardiography within 24 h, with LV analysis performed by the techniques of (1) atrioventricular plane displacement (AVPD) and (2) mitral valve leaflet coaptation point to interventricular septum distance at end-systole (MVC-IVS). Results: Thirteen patients had an echocardiogram with poor two-dimensional visualization of LV endocardial borders. One patient could not be evaluated by the MVC-IVS method and two others by the AVPD method because of technical limitations. Chi-square analysis to compare how each method could discriminate between an RNCA LVEF of < or ≥ 50% demonstrated high correlations for the AVPD method (r = 0.6530, p < 0.0005) and the MVC-IVS method (r = –0.7029, p < 0.0001). Sensitivity, specificity, positive and negative predictive values, and test accuracy for the AVPD and MVC-IVS methods were 85 and 80%, 88 and 94%, 85 and 92%, 82 and 83%, and 83 and 87%, respectively. Conclusion: This pilot study demonstrates that both alternative echocardiographic methods may be useful in the assessment of LV systolic performance, even in the setting of poor LV endocardial border visualization. A larger study is warranted to apply and contrast these methods in different patient subsets.
Enzymatic variation in the Varipalpus group of Aedes (Ochlerotatus) (Diptera: Culicidae)

Polyacrylamide gel electrophoresis was used to examine isozyme variation in 15 populations among five species of the Varipalpus group of Aedes (Ochlerotatus) . Two related species of tree-hole breeding Aedes, A. muelleri Dyar and A. purpureipes Aitken, were also examined. Ten enzyme loci were used. Aedes sierrensis (Ludlow) displayed little variation in enzyme phenotypes throughout a 2,000-km range from San Diego, Calif., to Seattle, Wash. Two diagnostic loci (ME and IDH-1) distinguished A. sierrensis from sympatric populations of A. deserticola Zavortink in California. Also, A. monticola Belkin & McDonald and A. varipalpus (Coquillett) were distinguished by diagnostic alleles at two enzyme loci (ODH and IDH-2). A. varipalpus samples were invariant at all loci examined. Two enzymes (MDH and α-GPD) appear to characterize the Varipalpus group and distinguish it from A. muelleri and A. purpureipes . Enzymatically, the Varipalpus group is a uniform assemblage of five species, although definite frequency differences exist among all members. Genetic variability in this study is similar to that reported in other Aedes studies. Phenetic cluster analysis and distance matrix trees produce different groupings of species than those suggested by morphological studies.
Experimental evaluation of laser-assisted machining of silicon carbide particle-reinforced aluminum matrix composites

An experimental study on machining of a particle-reinforced metal matrix composite (MMC) subjected to laser-assisted machining (LAM) was conducted. The MMC studied is an A359 aluminum matrix composite reinforced with 20 % by volume fraction silicon carbide particles. LAM was evaluated experimentally for its potential to improve machinability while minimizing the subsurface damage. The effectiveness of LAM was studied by measuring the cutting forces, specific cutting energy, surface roughness, subsurface damage, and tool wear under various material removal temperatures (Tmr). The optimum Tmr is established as 300 °C, with LAM providing a 37 % reduction in the surface roughness, a 12 % reduction in the specific cutting energy, and 1.7–2.35 times improvement in tool life over conventional machining dependent on the cutting speed.
On the effect of time-ordering for Lyman-α

Numerical calculations of the wings of the hydrogen Lyman-alpha line due to Stark broadening by electrons have been performed including time ordering effects. It is concluded that two recent calculations, which apparently disagree, are numerically correct within their respective approximations and their differences are explained.
SIR-based call admission control for DS-CDMA cellular systems

Signal-to-interference ratio (SIR)-based call admission control (CAC) algorithms are proposed and studied in a DS-CDMA cellular system. Residual capacity is introduced as the additional number of initial calls a base station can accept such that system-wide outage probability will be guaranteed to remain below a certain level. The residual capacity at each cell is updated dynamically according to the reverse-link SIR measurements at the base station. A 2/sup k/ factorial experimental design and analysis via computer simulations is used to study the impact of the parameters used in the algorithms. The influence of these parameters on system performance, namely blocking probability and outage probability, is then examined via simulation. The performance of the algorithms is compared together with that of a fixed call admission control scheme (fixed CAC) under both homogeneous and hot spot traffic loading. The results show that SIR-based CAC always outperforms fixed CAC even under overload situations, which is not the case in FDMA/TDMA cellular systems. The primary benefit of SIR-based CAC in DS-CDMA cellular systems, however, lies in improving the system performance under hot spot traffic. >
No clear winner among dressings for partial-thickness burns

Methods Data Sources The authors searched the Cochrane Central Register of Controlled Trials (CENTRAL) and the Cochrane Wounds Group Specialized Register (May 29, 2008), MEDLINE (1950 to May 2008), EMBASE (1980 to May 2008), and CINAHL (1982 to May 2008). Study Selection The review included randomized controlled trials examining various burn dressings, frequently using silver sulfadiazine as a control. Dressing types included the following: •Hydrocolloids (eg, DuoDerm; ConvaTec Ltd, Skillman, NJ): 5 studies; 314 patients •Polyurethane films (eg, Tegaderm; 3M, St. Paul, MN): 2 studies; 106 patients •Hydrogels (eg, Curagel; Kendall, Mansfield, MA): 2 studies; 115 patients •Silicon-coated nylon (eg, Mepitel; Molnlycke Health Care, Norcross, GA): 2 studies; 142 patients •Biosynthetic skin substitutes (eg, Biobrane; Smith & Nephew, Largo, FL): 10 studies; 441 patients •Silver impregnated (eg, Acticoat; Smith & Nephew, Largo, FL): 3 studies; 162 patients •Hydrofiber (eg, Aquacel; ConvaTec Ltd): 2 studies; 152 patients Studies addressing topical skin agents, full-thickness burns, hand burns, and biological skin replacements were excluded. The primary outcomes included time to complete wound healing and change in wound surface area over time. Secondary outcomes included number of dressing changes, pain, patient satisfaction, infection rate, need for surgery, cost, and hospital length of stay. Data Extraction and Synthesis Studies were reviewed by 2 authors independently and data were abstracted using standardized forms. The authors abstracted and pooled data from eligible studies by using appropriate analytical methods according to the Cochrane Handbook , version 5.0.0. Studies were assessed for the adequacy of randomization and allocation concealment, blinding of providers and participants, potential selection bias after allocation, and completeness of follow-up.
Molecular basis of pituitary dysfunction in mouse and human.

The pituitary gland functions as an intermediary between the brain and the peripheral endocrine organs of the body (Tortora and Grabowski 1996). In the context of a complex system of feedback control, the pituitary gland relays signals from the hypothalamus to its target organs by secreting various hormones. These hormone signals, which are transmitted throughout the endocrine system, reflect the current homeostatic conditions of the body. Mechanisms of compensation, including the regulation of gene transcription, hormone secretion, and cell proliferation, allow the pituitary to respond to the continually changing needs of the organism. It is in this way that the pituitary aids in the regulation of many vital processes, including growth, metabolism, reproduction, and stress response. The mammalian pituitary is comprised of three lobes: the posterior lobe, the intermediate lobe, and the anterior lobe. The anterior lobe of the pituitary is composed of functionally distinct cell types that are the primary site of endocrine regulation. During embryogenesis, the anterior and intermediate lobes of the pituitary develop from an invagination in the oral ectoderm known as Rathke’s pouch (Dubois and ElAmraoui 1995). The pouch eventually separates from the oral ectoderm and undergoes a period of intense proliferation. This is followed by differentiation into the five anterior pituitary cell types on the rostral side of the pouch and the intermediate lobe melanotropes on the caudal side of the pouch (Dubois and Hemming 1991). By birth, the anterior pituitary is composed of functioning corticotropes, thyrotropes, somatotropes, gonadotropes, and lactotropes that produce adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), growth hormone (GH), gonadotropins (FSH and LH), and prolactin (PRL), respectively. Expression of each hormone gene, which defines the terminal differentiation of each cell type, occurs in a spatially and temporally specific manner during pituitary organogenesis (Japon et al. 1994; Burrows et al. 1999). The mechanisms that control this process involve the secretion of signals from surrounding structures and the expression of a cascade of homeodomain transcription factors. Studies in both mouse and human reveal that control of signaling events and homeobox gene expression is essential for proper pituitary gland development (Watkins-Chow and Camper 1998; Dasen and Rosenfeld 1999). Deregulation of these events can lead to various forms of pituitary gland dysfunction, including hypopituitarism and adenomas.
Investigation of the effect of carbon monoxide on the oxidative carbonylation of methanol to dimethyl carbonate over Cu+X and Cu+ZSM-5 zeolites

Direct synthesis of dimethyl carbonate offers prospects for a “green chemistry” replacement to eliminate use of phosgene for polymer production and other processes. The carbonylation of methanol to produce dimethyl carbonate over Cu+X and Cu+ZSM-5 zeolites prepared by solid-state ion exchange has been investigated, focusing on the interaction of carbon monoxide with the Cu+ zeolites. The methanol carbonylation mechanism reported previously has been extended to account for carbon monoxide adsorption at high pressure. The comparison of the results obtained from Cu+X and Cu+ZSM-5 show that strong CO adsorption on the catalyst is not related to increased rate of dimethyl carbonate production. The rate limiting step for DMC production is best described as the Eley-Rideal reaction of gas-phase CO with surface methoxide.
Density-driven groundwater flow in closed desert basins: field investigations and numerical experiments

Abstract With a numerical model, Duffy and Al-Hassan demonstrated that free convection of brine could occur under the playa lake in a closed basin. Since then, continued effort has been made to further our understanding of the role of free convection in closed basin hydrology. In this paper we present the results of 5 years of field investigation in Pilot Valley, Nevada, of a literature search for field studies in closed basins around the world, and of numerical simulations to examine the effect of heterogeneity on free convection and the effect of climate changes. Observations along the divide–playa transect revealed evidence of forced convective flow and the existence of a hinge line. The salinity profile and the inferred flux suggest that diffusion is the dominant solute transport mechanism under the field sites, but the stable isotopes (O, H) suggest that free convection of playa brine also occurs. We propose a model that explains these observations. First, free convection could occur farther out on the playa where the density of surface brines is higher. Second, once free convective flow penetrates the surface sediments, it could migrate laterally in the more permeable layers of alluvium. Third, free convection could occur during periods of time when brines pond on the surface for extended periods. The search for field studies of groundwater processes in other closed basins leads to a few cases where free convection has occurred on a basin scale. Based on this survey, we discuss the geologic and climatic conditions that favor free convection. Numerical simulations are carried out to examine the effect of basin-scale heterogeneity in hydraulic conductivity. The results indicate that heterogeneity changes the pattern of flow by creating multiple convection cells. Finally we address how a closed basin may respond to climate change. Climate changes alter the salinity of surface brines and the freshwater recharge, both acting as `boundary conditions' for subsurface processes. Using dimensional analysis and numerical simulations, we evaluate the effect of a warming and drying trend on free convection, and how the geologic features of a closed basin affect the response. ©1997 Elsevier Science B.V.
Patterns of Breast Magnetic Resonance Imaging Use: An Opportunity for Data-Driven Resource Allocation

Both theAmericanCancerSociety1and theNationalComprehensiveCancerNetwork2havepublishedguidelinesonthe recommended use of breast magnetic resonance imaging (MRI). In both sets of guidelines, lifetime breast cancer risk greater than 20%has been established as an acceptable threshold for annualMRI screeningwhenused togetherwith annualmammography screening. Routine breast MRI screening is not recommended for a new cancer diagnosis or for cancer surveillance. Nevertheless,MRI remains frequentlyused for theseother indications. A systematic review of the accuracy of MRI and its impact on surgical treatment of breast cancer showed that the use of MRI for treatment planning is widespread, although its benefit remains difficult todemonstrate.3 For evaluation of the contralateral breast in patients with a new diagnosis of breast cancer, the American College of Radiology Imaging Network (ACRIN) 6667 trial found that the contralateral breast cancer detection rate with breast MRI was 3.1%, indicating possible utility in this setting.4Recent studieshavealso indicatedvalue forbreastMRI inneoadjuvant treatmentwherebreastMRImay have clinical utility both in treatment planning and as a prognosticmarker.5 As yet, however, the impact ofMRI on clinical management has not been linked to improvements in breast cancer outcomes.
Tacit and explicit knowledge: empirical investigation in an emergency regime

Tacit knowledge has long been recognised as an important component of how individuals perform. But how can tacit knowledge be measured in organisational situations? This paper explores the role of tacit knowledge in performance of individuals and teams in emergency regime of the Emergency Department (ED) of a main hospital. Content analysis of two cases support the proposition that when explicit research – in the form of protocols of care – are unsuccessful, yet a patient is saved, tacit knowledge is the only component of knowledge that can explain this surge in performance.
Absorption of milk-borne insulin-like growth factor-I into portal blood of suckling rats.

Background: Insulin-like growth factors (IGFs) are potent mitogens that have been implicated in control of growth and development during the perinatal period. These hormones are also present in biologically significant quantities in mammalian milks. Although one site of action of these IGFs may be at the intestinal level, current information about whether they pass intact into the circulation is conflicting. Methods: To test the hypothesis that milk-borne IGFs are absorbed into blood in receptor-active form, suckling rats were given either recombinant human (rh) 125 I-IGF-I or -II (4 × 10 6 counts per minute [cpm]), and the activity present in portal and cardiac blood was examined at 5, 10, 20, and 30 minutes after ingestion for presence of appropriate molecular weight peptides in these samples. In selected samples, purified radioactive samples were tested for their ability to bind competitively to crude membranes bearing IGF receptors. Results: The results of these studies indicate that rh 125 I-IGF-I is absorbed in receptor-active form into the portal circulation and that maximal amounts are present 20 to 30 minutes after ingestion. Estimation of the presence of intact hormone was made on the basis of the elution profile of samples when run on gel chromatography as well as reversed-phase high-performance liquid chromatography. Isolated samples from portal blood also bound competitively to placental membranes bearing IGF receptors. In contrast, rh 125 I-IGF-II could not be demonstrated in receptor-active form in portal blood. Chromatography showed appropriate sized peaks with greater activity in portal than cardiac samples, but competitive binding was not appreciated. Conclusions: It is likely that at least milk-borne IGF-I is absorbed intact and may exert effects on liver and other peripheral tissues. In addition, this study lends further credence to the possibility of an enterohepatic circulation for IGF-I.