cssi/SciSciGPT-SciSciNet huggingface dataset:
Second Order Optical Effects In Multilayer Polymeric Thin Films

Multilayer Langmuir/Blodgett thin films provide a means of designing thin film optical devices monolayer by monolayer. A single layer of a hemicyanine dye or a mixture of hemicyanine dye and PMMA, as the polymeric host, produce second harmonic generation (SHG). With proper dipping procedure it is possible to deposit such films one monolayer at a time and maintain the noncentrosymmetric structure required for SHG. Addition of more layers of the same material increases the amount of generated second harmonic. This evidence of enhanced second harmonic generation in multilayer Langmuir/Blodgett thin films will be presented. Discussion of microwave detection using the linear electrooptic effect in slab and coated fiber structures will be presented. Some of the theoretical problems and advantages of using optical fibers coated by Langmuir/Blodgett films are discussed. Emphasis is placed on the importance of developing in situ diagnostic tools for use during deposition of the organic films.
Similar functional anatomy of spontaneous and precipitated morphine withdrawal

The distribution and magnitude of changes in regional cerebral glucose utilization were similar whether opiate withdrawal was spontaneous or naloxone induced.
Synthesis of halogenated pregnanes, mechanistic probes of steroid hydroxylases CYP17A1 and CYP21A2

The human steroidogenic cytochromes P450 CYP17A1 (P450c17, 17α-hydroxylase/17,20-lyase) and CYP21A2 (P450c21, 21-hydroxylase) are required for the biosynthesis of androgens, glucocorticoids, and mineralocorticoids. Both enzymes hydroxylate progesterone at adjacent, distal carbon atoms and show limited tolerance for substrate modification. Halogenated substrate analogs have been employed for many years to probe cytochrome P450 catalysis and to block sites of reactivity, particularly for potential drugs. Consequently, we developed efficient synthetic approaches to introducing one or more halogen atom to the 17- and 21-positions of progesterone and pregnenolone. In particular, novel 21,21,21-tribromoprogesterone and 21,21,21-trichloroprogesterone were synthesized using the nucleophilic addition of either bromoform or chloroform anion onto an aldehyde precursor as the key step to introduce the trihalomethyl moieties. When incubated with microsomes from yeast expressing human CYP21A2 or CYP17A1 with P450-oxidoreductase, CYP21A2 metabolized 17-fluoroprogesterone to a single product, whereas incubations with CYP17A1 gave no products. Halogenated steroids provide a robust system for exploring the substrate tolerance and catalytic plasticity of human steroid hydroxylases.
Transurethral radio frequency ablation of the prostate

Since 1993, radiofrequency ablation of the prostate has been studied as a potential treatment for symptomatic bladder outlet obstruction due to benign prostatic hyperplasia. Two transurethral radiofrequency delivery systems have been developed to the point of undergoing initial human clinical trials. The TUNATM system involves focal interstitial radiofrequency energy application, while the TURAPYTM system involves a circumferential application of radiofrequency energy to the prostatic urethra via a simple delivery catheter. Experimental studies in animal models and human prostate tissue have demonstrated the nature of radiofrequency induced tissue heating and thermal injury. Observed thermal effects are relatively focused, with steep temperature gradients occurring over a few millimeters from the radiofrequency emission source. This allows precise and focused tissue treatment with little or no danger of injury to surrounding structures. Early human clinical experience in the treatment of benign prostatic hyperplasia has demonstrated efficacy in the relief of voiding symptoms and safety and minimal morbidity associated with this technology. The existing operative approaches are relatively simple. Ongoing development of more versatile delivery systems for radiofrequency ablation of the prostate is expected. Results from larger clinical trials with longer term followup will eventually allow adequate assessment of the role of radiofrequency ablation in the surgical management of benign prostatic hyperplasia.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Engineering Properties of Polymer-Modified Asphalt Mixtures:

A large research program sponsored by the Michigan Department of Transportation was designed and completed to evaluate the effect of polymer modification on the various properties of asphalt mixtures. These include the micro- and macrostructural, morphological, chemical, and engineering properties. Some of the engineering properties of the styrene-butadiene-styrene and styrene-etylene-butylene-styrene polymer-modified asphalt mixtures are presented and discussed. The elastic, fatigue, tensile, and permanent deformation properties were investigated at 60, 25, and —5° C. It was found that, for some polymer systems, the fatigue life and the indirect tensile strength increased considerably at 25° C while the elastic properties at -5° C were not affected by the addition of polymer. The implication of this is that the use of some polymer systems in asphalt mixtures enhances their fatigue cracking and rutting resistance without affecting the low temperature cracking potential.
Increasing registration precision for liver movement with respiration using electromagnetic tracking

Abstract Respiratory motion of the liver is a major concern when trying to precisely target liver lesions. The purpose of this study is to increase the accuracy of an image-guided system for abdominal interventions by tracking multiple needles within the liver and selecting the time stamp that provides the smallest registration error throughout the whole respiratory cycle. Phantom and swine studies have been completed. The results indicate that the method presented can increase the precision of registration compensation compared with respiratory gating and non-gating methods.
Reaction of 3-amino-1:2:4-triazole with bovine liver catalase and human erythrocyte catalase.

Abstract The stoichiometry of the reaction of 3-amino-1:2:4-triazole with catalase is different for bovine liver and human erythrocyte catalases, and can be correlated with the hematin content of the two types of catalase. A specific histidyl residue in catalase is modified, but an intact hematin appears to be necessary for binding of hydrogen peroxide before reaction with aminotriazole can occur.
Book Review of Stroke Rehabilitation

Excerpt To the editor: Although I was disturbed when I originally read the review ofStroke Rehabilitation(1) by Dr. McDowell (2), I did not write to the journal in recognition of the propriety of a...
The overlearning reversal effect in monkeys provided a salient irrelevant dimension

Capuchin monkeys were first trained on a color discrimination and then reversed. Later these same colors formed irrelevant background cues for a form discrimination. Despite the ready availability of the irrelevant (color) dimension, the controls reversed the form discrimination just as fast as overtrained Ss. Yet the controls reverted to color earlier than the overtrained Ss and responded to it more frequently during the first 80 reversal trials.
The meteoritic chromium isotopic composition and limits for radioactive 53Mn in the early solar system

We have studied the Cr isotopic composition of early solar system samples to search for anomalies caused by either the decay of extinct radio-nuclide 53Mn or the nucleosynthetic heterogeneities in Cr itself. The samples are spinels from five Allende inclusions, one “chromite carbon” Allende residue, and olivines from both Eagle Station pallasite and Angra dos Reis pyroxenite. We have also analyzed silicates from five Allende inclusions which are known to have a variety of anomalies. Our detection limits are 0.6%. and 1.4%. for fractionation corrected 53Cr52Cr and 54Cr52Cr, respectively. No isotopic effects beyond these limits were found among the samples studied. The limits for 53Mn55Mn for Allende Cr-rich phases, Eagle Station, and Angra dos Reis are inferred to be 85, 11, and 2.8 × 10−6 at their respective formation times. The lack of detectable 53Mn effects could be due to late formation of the high MnCr phases and heterogeneity in the 53Mn distribution for the low MnCr samples. It may also be caused by unusually large dilution factor for Mn. The lack of 53Cr effect does not support models in which the pre-solar source for the 26Al was a massive star. Neither does it support a proton irradiation production for 26Al. Our relatively poor detection limit on 54Cr does not permit verification of small (≲.8%.) effects reported recently by Birck and Allegre (1984).
IQGAP1-dependent signaling pathway regulates endothelial cell proliferation and angiogenesis.

Background: Vascular endothelial growth factor receptor-2 (VEGFR-2) signaling is an obligate requirement for normal development and pathological angiogenesis such as cancer and age-related macular degeneration. Although autophosphorylation of tyrosine 1173 (Y1173) of VEGFR-2 is considered a focal point for its angiogenic signal relay, however, the mechanism of phosphorylation of Y1173, signaling proteins that are recruited to this residue and their role in angiogenesis is not fully understood. Methodology/Principal Findings: In this study we demonstrate that c-Src kinase directly through its Src homology 2 (SH2) domain and indirectly via c-Cbl binds to phospho-Y1057 of VEGFR-2. Activation of c-Src kinase by a positive feedback mechanism phosphorylates VEGFR-2 at multi-docking site, Y1173. c-Src also catalyzes tyrosine phosphorylation of IQGAP1 and acts as an adaptor to bridge IQGAP1 to VEGFR-2. In turn, IQGAP1 activates b-Raf and mediates proliferation of endothelial cells. Silencing expression of IQGAP1 and b-Raf revealed that their activity is essential for VEGF to stimulate angiogenesis in an in vivo angiogenesis model of chicken chorioallantoic membrane (CAM). Conclusions/Significance: Angiogenesis contributes to the pathology of numerous human diseases ranging from cancer to age-related macular degeneration. Determining molecular mechanism of tyrosine phosphorylation of VEGFR-2 and identification of molecules that are relaying its angiogenic signaling may identify novel targets for therapeutic intervention against angiogenesis-associated diseases. Our study shows that recruitment and activation of c-Src by VEGFR-2 plays a pivotal role in relaying angiogenic signaling of VEGFR-2; it phosphorylates VEGFR-2 at Y1173, facilitates association and activation of IQGAP1 and other signaling proteins to VEGFR-2. IQGAP1-dependent signaling, in part, is critically required for endothelial cell proliferation, a key step in angiogenesis. Thus, Y1057 of VEGFR-2 serves to regulate VEGFR-2 function in a combinatorial manner by supporting both diversity of recruitment of angiogenic signaling proteins to VEGFR-2, and its ability to promote angiogenesis.
Becoming a (Pan)ethnic Attorney: How Asian American and Latino Law Students Manage Dual Identities

Managing professional and personal identities often belabor upwardly mobile racialized individuals. I examine in this article how Asian American and Latino law students negotiate (pan)ethnic identities while learning to become lawyers. I contend that managing dual identities creates (pan)ethnic duty among Asian American and Latino law students. I focus on those planning to work in law firms, at least initially. While there are many career options for law students, most, irrespective of race, pursue initial careers at law firms. What leads them there? How do racialization and expectations play a role in this career aspiration? And how do students negotiate the pressure to give back, or manage the internally/externally imposed duty they feel to serve respective communities? I find that Asian American and Latino law students draw on a repertoire of strategies (marginal panethnicity, tempered altruism, and instrumental ethnicity) that encompass different accounts, identities, and roles enabling creativity and elasticity for professional and personal identities. The findings suggest that panethnicity remains salient for upwardly mobile individuals of color, even those who do not ostensibly appear to be concerned with panethnic communities and causes.
Visualizing worm micelle dynamics and phase transitions of a charged diblock copolymer in water.

Assemblies of block copolymer amphiphiles are sometimes viewed as glassy, frozen, or static colloids, especially in strongly segregating solutions. Here, we visualize by fluorescence microscopy and AFM the dynamics and transitions of single cylindrical micelles and vesicles composed of a charged diblock copolymer in water. In mapping the salt- and pH-dependent phase diagrams of a near-symmetric diblock of poly(acrylic acid)-polybutadiene, low pH and high salt (NaCl, CaCl2) neutralize and screen the charged corona sufficiently to foster membrane formation and generate vesicles. Decreased salt and neutral pH increases intra-coronal repulsion and drives a transition to multi-branched cylinders and highly stable, but fluid and flexible, worm micelles. Ca2+ both stiffens cylinders and stabilizes them relative to spheres. Further increase of intra-coronal repulsion generates spherical micelles by fragmentation and pinch-off at the ends of worms. Both the transition kinetics and phase diagrams indicate divalent ...
Seismic Data Mapping

This work describes Seismic Data Mapping (SDM), its definition, properties, applications, limitations and goals. A variety of problems such as offset-continuation, azimuthal-continuation (AMO), layer replacement and datuming can be cast as special cases of SDM. In general, this process is a cascade of prestack migration and inverse migration (demigration). We find a simplification of the operator that requires less computational effort than either the individual prestack migration and demigration processes that generated it.
Prostate cancer: making the switch from LHRH antagonist to LHRH agonist.

One very important issue faced by clinicians managing patients with prostate cancer is whether after initiating a man on a pure luteinizing-hormone-releasing hormone (LHRH) antagonist, he should then be switched to a longer-acting depot LHRH agonist. New evidence suggests that this therapeutic approach is both safe and effective.
Selection of Pattern Features by Mathematical Programming Algorithms

The selection of a "best" subset of features from a given set is considered for the case where a multiplicity of constraints are present in the two-class pattern recognition problem. The problem can be formulated with a Lagrangian multiplier and an efficient iterative technique used in conjunction with dynamic programming procedures to obtain a solution when two constraints are present. The problem can be formulated in integer programming terms and use made of available integer programming computer algorithms for solution when multiple constraints are present. The Lemke-Spielberg zero-one integer algorithm is particularly useful, but other integer programming algorithms can be used also.
Mass spectrometric methods for determination of [13C]leucine enrichment in human muscle protein

Abstract Two modified GC-based isotope ratio MS (IRMS) techniques, for measurement of [13C]leucine enrichment in muscle protein, were compared with a conventional dual inlet technique. Of these three, two involved HPLC purification of leucine and liberation of carbon dioxide (CO2) using the ninhydrin reaction. In the conventional technique the CO2was introduced into the MS by a dual inlet system following cryogenic concentration. In the second method (ninhydrin/GC/IRMS) the CO2was purified by on-line GC. In the third technique, GC/combustion/IRMS, derivatized amino acids are separated by GC and analyzed after combustion. A primed continuous infusion of L -[1-13C]leucine was given intravenously to human subjects and needle quadriceps muscle biopsies were taken to measure [13C]leucine enrichment in muscle protein. All three methods demonstrated excellent correlation (r> 0.999). Differences in the measurement of [13C]leucine enrichment in muscle protein were
Conversational implicature in a second language: learned slowly when not deliberately taught

Abstract The importance of conversational implicature (Grice, 1975) in expressing a message indirectly is well established. Yet Keenan (1976) has shown that members of different cultures derive different implicatures from the same utterance in essentially the same context, and Bouton (1988) found that even reasonably proficient nonnative speakers (NNS) of English (average TOEFL score = 550) interpret implicatures differently from American native speakers (NS) 21% of the time. Yet relatively few examples of implicature appear in ESL textbooks and few of those are dealt with directly (Bouton, 1990). These facts, then, suggest that little attempt is made in the ESL/EFL classroom to make learners aware of implicature as a tool of communication or to give them practice at using it in English. And this raises a question: can NNS learn to use implicature with little or no direct instruction. To investigate this question, two groups of international students at an American university who had been tested with regard to their ability to interpret implicatures when they first arrived on campus were tested again 18 and 54 months later, respectively. This paper reports on their progress in regard both to the overall set of implicatures and to various specific types identified during the original study.
Understanding opportunities and challenges for collaborative greenway planning in New England

Protection of natural, cultural, and recreational resources requires a regional approach to greenway planning that transcends political boundaries. Previous research on greenway planning has shown there are four main challenges in multi-jurisdictional greenway implementation: inter-governmental coordination, the lack of regional governance, funding, and public perceptions about greenways. The focus of this study was to understand successful strategies for collaborative greenway planning in the fragmented political landscape of New England (USA). To understand these issues, in-depth interviews were conducted with key greenway planners in New England from federal and state agencies and non-governmental organizations. The results of the study revealed four key strategies that are essential to multi-jurisdictional greenway planning in New England: partnerships, clearly defined goals, public involvement, and regional coordination. This study provides lessons for greenway planners who are implementing regional greenways across state, provincial, and international boundaries.
Sliding fragility of block‐type non‐structural components. Part 2: Restrained components

This paper focuses on seismic vulnerability assessment of restrained block-type non-structural components under sliding response on the basis of seismic inputs specified by current seismic codes. The general representation of restrained equipment considered in this study consists of a rigid block restrained by four post-tensioned, symmetrically arranged cables. Two sliding-related failure modes are considered: restraint breakage and excessive absolute acceleration. Fragility analysis is proposed as an appropriate tool to evaluate these failure modes. Sample fragility curves developed through Monte-Carlo simulations show that the restraint breakage limit state is sensitive to the parameters of the equation of motion. For instance, fragility estimates obtained without taking into account vertical base accelerations can be significantly unconservative for relatively large values of the coefficient of friction. In contrast, the excessive absolute acceleration limit state exhibits little sensitivity to the parameters of the equation of motion. Peak absolute acceleration response is almost always equal to or greater than the horizontal peak base acceleration. Representative results suggest that reasonable response estimates for blocks located at stories other than the ground in multistorey buildings can in general be obtained by simply scaling the ground acceleration to the peak acceleration at the corresponding storey. Copyright © 2002 John Wiley & Sons, Ltd.
Ties between lexical and grammatical development: evidence from early-talkers*

Case studies are presented for two linguistically precocious children (early-talkers) aged 1;9 and 1;5, one of whom represents a striking dissociation between vocabulary size and mean length of utterance. Each early-talker is compared to controls in the same language stage; 10 in Early Stage I (mean age 1; 7) and 10 in Stage II (mean age 2; 3). Data are explored to determine if the dissociation is best characterized as one between grammar and semantics, or a difference in cognitive style. Results showed that the child who used mostly single words produced high proportions of predicates and bound and closed class grammatical morphemes, providing no evidence of a dissociation between grammar and semantics. Results also failed to support a clear contrast between analytic and holistic processing, although partial support was found for some predictions based on cognitive style. A unifying account is proposed that considers differences in auditory short term memory, a factor which could affect the size of the linguistic unit that children can store, manipulate, and/or retrieve at a particular point in development.
Stiffness Matrices of Isoparametric Four-Node Finite Elements by Exact Analytical Integration

Explicit algebraic expressions needed to compute element stiffness matrices using procedural (FORTRAN) and object oriented ( C++ ) computer programs are presented. Numerical illustrations for a convex quadrilateral and a triangle with a side node are included. The wide controversy due to conventional element level approximate numerical quadrature within the computational square domain in η and ξ coordinates is completely resolved here by the closed form analytical integration within the physical element, in x and y coordinates.
Searching for Success: Defining Success in Co-Management

Much of the co-management literature is dedicated to determining the conditions that allow for successful management of natural resources. However, what constitutes "success" is often left undefined. In practice, though, it is clear that different actors have different ways of conceptualizing success. This paper examines how different actors define success in the context of a common property system in southwestern France that is transitioning to a co-management system. Different definitions of success employed by different stakeholders in the process stemmed from their different objectives for the project, their differential experiences of the implementation process, relationships between Basque farmers and the French state and the European Union, senses of identity, and the effects of scale. I argue that in order to facilitate more informed project design and evaluation, we need to be clear in our writings about how success is defined, whose definition we are using, and how that definition is contested a...
Buying a better witch doctor: Witch-finding, neoliberalism, and the development imagination in the Taita Hills, Kenya

In this article, I examine the efforts of a Kenyan community to make sense of, and to act on, structural transformations associated with economic and political liberalization and globalization. To locate the sources of its conjoined moral and economic decline, the community employed the witch finder Maji Marefu to expose the real circuits of power and abuse underlying the false appearances of everyday life and to make the institutions and practices long associated with “development” real again through the ritualized public exposure of new forms of witchcraft. Maji Marefu's “movement” sought to revitalize institutions that were iconic of an earlier model of development, coming to life in the vacuum that a retreating, downsized state left behind. Yet Maji Marefu ultimately came to epitomize the foreign vices he was hired to rid the community of, and the state and church were revitalized to intervene on the citizenry's behalf so as to control this “criminal” menace.
Development of a PET radiotracer for non-invasive imaging of the reactive oxygen species, superoxide, in vivo.

Reactive oxygen species (ROS) have been implicated in the pathogenesis of a wide range of human disease states and drug toxicities, but development of imaging tools to study ROS biology in vivo remains a challenge. Here we synthesized and validated a novel PET tracer (12) and its 18F radiolabeled version [18F]12 to allow PET (positron emission tomography) imaging of superoxide in vivo. Initial analysis of ROS reaction kinetics found that compound 12 was rapidly and selectively oxidized by superoxide, but not other ROS. Cell culture studies in EMT6 cells exposed to the cancer chemotherapeutic agent Doxorubicin (DOX), which activates the superoxide-generating enzyme, NADPH oxidase, showed that compound 12 was a sensitive and specific probe for superoxide in cells. The microPET imaging of heart in mice with DOX-induced cardiac inflammation observed 2-fold greater oxidation of [18F]12 in the DOX-treated mice compared to controls (p = 0.02), the results were confirmed by distribution studies on organs subsequently removed from the mice and HPLC analysis of [18F] radioactivity compounds. These data indicate that compound 12 is a useful PET tracer to imaging ROS in vivo.
Reduction of intracellular calcium removal rate can explain changes in seizure dynamics: studies in neuronal network models

Complex partial seizures originating from mesial temporal structures are characterized by relatively short durations of organized rhythmic activity (ORA) of 5-8 Hz, typically lasting less than 60s. Previous investigations into seizure dynamics have revealed that this ORA undergoes a monotonic decline prior to seizure evolution into intermittent bursting and subsequent seizure termination. Large neural network models of simplified single-compartment neurons were employed to address the hypothesis that changes in the free intracellular calcium ([Ca2+]i) removal rate during network bursting can result in the alterations of rhythmic seizure activity similar to that observed in recordings from humans. Both exponential and linear models of decreasing calcium removal rates resulted in changes in the predominant frequency of network bursting very similar in frequency and time course to those seen in human intracranial recordings. This supports the concept that changes in [Ca2+]i removal can explain this important network behavior, while not excluding alternative hypotheses. Identifying potential mechanisms underlying the dynamic changes seen in epileptogenic activity in large neural networks can provide important insights into seizure evolution and termination. Model neural network ensembles are attractive systems to address these questions that are difficult to investigate in biological preparations.
Algorithm to automatically detect abnormally long periods of inactivity in a home

An algorithm has been developed to automatically construct individual models of normal activity within a home using motion sensor data. Alerts can be generated when a period of inactivity exceeds a normal length for a particular residence. Alerting frequency has been optimized on a total of 650 days of real data from four homes of seniors who live independently. Results suggest that an inexpensive system that does not require the occupant to push any buttons or wear any devices could nonetheless alert within hours if a senior is unusually inactive. Further, such algorithms may facilitate widespread deployment of smart home technology to persons with different behavior patterns and home layouts by using automatic learning in place of potentially tedious manual configuration.
Erythromycin Prophylaxis for Recurrent Otitis Media

Patients with recurrent otitis media without persistent middle ear effusion were studied for antibiotic prophylaxis efficacy. In the first phase, erythromycin ethylsuccinate was used as prophylaxis for otitis media in 45 patients in a dose of 10 mg/kg twice daily. Acute otitis media occurred in eight of 45 (18%) while receiving erythromycin, and in 22 of 41 (54%) following prophylaxis termination. The attack rate (episodes of otitis media per 2-month period) was 0.86 before prophylaxis, 0.20 during prophylaxis, and 0.79 following prophylaxis.In a second phase of the study, erythromycin was compared with sulfisoxazole for otitis media prophylaxis in a group of 42 children. Sulfisoxazole (500 mg per dose) was administered twice daily. Acute otitis media occurred in five of 28 (18%) children while receiving erythromycin and in nine of 21 (43%) children while receiving no prophylaxis. The attack rate (episodes of otitis media per 2-month period) was 0.81 before erythromycin prophylaxis, 0.18 while receiving e...
Role of muscle loss in the age-associated reduction in VO2 max

A progressive decline in maximal O2 consumption (VO2max) expressed traditionally as per kilogram body weight generally occurs with advancing age. To investigate the extent to which this decline could be attributable to the age-associated loss of metabolically active tissue, i.e., muscle, we measured 24-h urinary creatinine excretion, an index of muscle mass, in 184 healthy nonobese volunteers, ages 22-87 yr, from the Baltimore Longitudinal Study of Aging who had achieved a true VO2max during graded treadmill exercise. A positive correlation was found between VO2max and creatinine excretion in both men (r = 0.64, P less than 0.001) and women (r = 0.47, P less than 0.001). As anticipated, VO2max showed a strong negative linear relationship with age in both men and women. Creatinine excretion also declined with age in men and women. When VO2max was normalized for creatinine excretion, the variance in the VO2max decline attributable to age declined from 60 to 14% in men and from 50 to 8% in women. Thus comparing the standard age regression of VO2max per kilogram body weight with that in which VO2max is normalized per milligram creatinine excretion, the decline in VO2max between a hypothetical 30 yr old and a 70 yr old was reduced from 39 to 18% in men and from 30 to 14% in women. We conclude that in both sexes, a large portion of the age-associated decline in VO2max in non-endurance-trained individuals is explicable by the loss of muscle mass, which is observed with advancing age.
Morphological Evolution Of Titanium Carbide Whiskers

The early growth of titanium carbide whiskers from mixtures of TiCl4-CH4-H2 was investigated. Fine nickel particles were the catalytic agent in a hot-wall CVD reactor. It was confirmed that whisker growth is initiated by the vapor-liquid-solid mechanism at the growth temperature of 1423 K. The initial growth proceeds by the diffusion of the constituent species through a Ni-Ti liquid droplet and is characterized by a rapid increase in whisker length, the diameter remaining essentially constant. In the later stage, the whiskers grow primarily in the axial direction at a reduced rate with a gradual increase in the diameter. The whisker diameter (D) and its rate of increase are independent of the nickel particle sizes, but increased proportionately to the reactant supersaturations. The whisker length (L) also increased with increasing nickel particle size and reactant supersaturation, resulting in large aspect ratios (L/D = 12.5). The whiskers exhibited extensive branching and kinking and a primary growth direction.
Interbilayer interactions from high-resolution x-ray scattering

The fundamental issue of interactions between lipid bilayers is addressed experimentally and theoretically. We report high-resolution x-ray scattering data for bilayers composed of three different kinds of phosphatidylcholine lipids. These data yield the interbilayer water spacing fluctuation $\ensuremath{\sigma},$ as well as the traditional osmotic pressure $P,$ both as functions of the lamellar repeat spacing $D$ and the aqueous separation $a.$ We show theoretically how to obtain the functional form of the fluctuational free energy from the $\ensuremath{\sigma}$ data, which is then determined to within a factor that depends upon the bending modulus, ${K}_{c}.$ The resulting functional form determined from experimental data has an exponential decay rather than the power law decay that applies for hard confinement in the large $a$ regime, thereby showing that a theory of soft confinement is necessary. However, the existing theory of soft confinement predicts an exponential decay, but with a smaller decay length ${\ensuremath{\lambda}}_{\mathrm{fl}}$ than we obtain. We then use these results to analyze the osmotic pressure data in terms of the bending modulus ${K}_{c}$ and the interbilayer interactions consisting of van der Waals and hydration interactions. For all three chemically different lipids we find that the decay length $\ensuremath{\lambda}$ of the hydration pressure is $1.9\ensuremath{-}2.0 \mathrm{\AA{}};$ the Hamaker parameter for the van der Waals interaction is about $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14} \mathrm{erg}$ if the bending moduli ${K}_{c}$ are chosen to be different for the three lipids and in the range $(0.5\ensuremath{-}0.8)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12} \mathrm{erg}.$
Interleukin-4 secretion by the allograft fails to affect the allograft-specific interleukin-4 response in vitro.

Background The role of the cytokine, interleukin (IL)-4, in allograft rejection and protection is not clear. We have previously shown that IL-4 transgenically expressed in a pancreas allograft does not protect the allograft from rejection. Here, we analyze the effect of the transgenically expressed IL-4 on the cytokine profile of the allograft-specific immune response. Methods. C57BL/6SCID mice were infused with small numbers of spleen cells from C57BL/6 donors. The former received pancreas grafts from 1- to 2-day-old BALB/c donors which did or did not transgenically express IL-4 in the graft. Three weeks after the cell infusion, the spleens were removed and the splenocytes were restimulated in vitro with BALB/c APC, and third party BALB.K APC. IL-2 and IL-4 levels in the culture supernatants were measured. Results. The presence of a pancreatic allograft induced an increase in the levels of both IL-2 and IL-4 in culture supernatants from splenocytes of mice receiving grafts compared with mice not receiving grafts. The presence of IL-4 transgenically expressed in the pancreas allograft had no effect on the in vitro cytokine profile. Conclusions. from these results we conclude that the failure of transgenically expressed IL-4 to protect the allograft was not associated with up-regulation of a graft antigen-specific IL-4 response.
Rapid Nitrate Loss and Denitrification in a Temperate River Floodplain

Nitrogen (N) pollution is a problem in many large temperate zone rivers, and N retention in river channels is often small in these systems. To determine the potential for floodplains to act as N sinks during overbank flooding, we combined monitoring, denitrification assays, and experimental nitrate (NO 3 − -N) additions to determine how the amount and form of N changed during flooding and the processes responsible for these changes in the Wisconsin River floodplain (USA). Spring flooding increased N concentrations in the floodplain to levels equal to the river. As discharge declined and connectivity between the river and floodplain was disrupted, total dissolved N decreased over 75% from 1.41 mg l−1, equivalent to source water in the Wisconsin River on 14 April 2001, to 0.34 mg l−1 on 22 April 2001. Simultaneously NO 3 − -N was attenuated almost 100% from 1.09 to <0.002 mg l−1. Unamended sediment denitrification rates were moderate (0–483 μg m−2 h−1) and seasonally variable, and activity was limited by the availability of NO 3 − -N on all dates. Two experimental NO 3 − -N pulse additions to floodplain water bodies confirmed rapid NO 3 − -N depletion. Over 80% of the observed NO 3 − -N decline was caused by hydrologic export for addition #1 but only 22% in addition #2. During the second addition, a significant fraction (>60%) of NO 3 − -N mass loss was not attributable to hydrologic losses or conversion to other forms of N, suggesting that denitrification was likely responsible for most of the NO 3 − -N disappearance. Floodplain capacity to decrease the dominant fraction of river borne N within days of inundation demonstrates that the Wisconsin River floodplain was an active N sink, that denitrification often drives N losses, and that enhancing connections between rivers and their floodplains may enhance overall retention and reduce N exports from large basins.
Fastpath Optimizations for Cluster Recovery in Shared-Disk Systems

We describe the design and implementation of a clustering service for a high-performance, shared-disk file system. The service provides failure detection and recovery, reliable end-to-end messaging, and a centralized and recoverable management interface. We implement novel optimizations in the voting protocol that resolves cluster membership. Optimizations allow clusters to form as quickly as possible without introducing livelock or requiring timeout parameters to be tuned carefully. Our treatment includes performance results that quantify the scalability of the system and measure recovery times.
Scaling, Universality, and Geomorphology

Theories of scaling apply wherever similarity exists across many scales. This similarity may be found in geometry and in dynamical processes. Universality arises when the qualitative character of a system is sufficient to quantitatively predict its essential features, such as the exponents that characterize scaling laws. Within geomorphology, two areas where the concepts of scaling and universality have found application are the geometry of river networks and the statistical structure of topography. We begin this review with a pedagogical presentation of scaling and universality. We then describe recent progress made in applying these ideas to networks and topography. This overview leads to a synthesis that attempts a classification of surface and network properties based on generic mechanisms and geometric constraints. We also briefly review how scaling and universality have been applied to related problems in sedimentology—specifically, the origin of stromatolites and the relation of the statistical pro...
Large-Eddy Simulations of Radiatively Driven Convection: Sensitivities to the Representation of Small Scales

Abstract Large-eddy simulations of a smoke cloud are examined with respect to their sensitivity to small scales as manifest in either the grid spacing or the subgrid-scale (SGS) model. Calculations based on a Smagorinsky SGS model are found to be more sensitive to the effective resolution of the simulation than are calculations based on the prognostic turbulent kinetic energy (TKE) SGS model. The difference between calculations based on the two SGS models is attributed to the advective transport, diffusive transport, and/or time-rate-of-change terms in the TKE equation. These terms are found to be leading order in the entrainment zone and allow the SGS TKE to behave in a way that tends to compensate for changes that result in larger or smaller resolved scale entrainment fluxes. This compensating behavior of the SGS TKE model is attributed to the fact that changes that reduce the resolved entrainment flux (viz., values of the eddy viscosity in the upper part of the PBL) simultaneously tend to increase the ...
Definition, Incidence, Risk Factors, and Prevention of Paralytic Ileus Following Radical Cystectomy: A Systematic Review

Abstract Context Postoperative paralytic ileus (POI) has profound clinical consequences because it represents a substantial burden on both patients and health care resources. Objective To determine the knowledge base regarding POI in the radical cystectomy (RC) population with an emphasis on preventive measures and risk factors. Evidence acquisition A systematic literature search of Medline (1966 to February 2011) and a study review were conducted. Eligible studies explicitly reported the incidence of POI and/or at least two quantitative measures of gastrointestinal recovery. Evidence synthesis The search identified 727 relevant articles; 77 met eligibility criteria, comprising 13 793 patients. Of these, 21 used explicit definitions of POI, and they varied widely. Across studies, the incidence of POI ranged from 1.58% to 23.5%. Possible risk factors for POI included increasing age and body mass index. Seventeen studies reported effects of an intervention on POI: 3 randomized controlled studies, 11 observational cohort studies with concurrent comparison, and 3 observational cohort studies with nonconcurrent comparison. Gum chewing was associated with shortened times to flatus (2.4 vs 2.9 d; p p n =102); omission of a postoperative nasogastric tube (NGT) was associated with shorter time to flatus (4.21 vs 5.33 d; p =0.0001) and shorter length of stay (14.4 vs 19.1 d; p =0.001) in one observational cohort study ( n =430); and the routine use of bowel preparation was associated with an increased incidence of POI (5% vs 19%) in another series ( n =86). Additionally, readaptation of the dorsolateral peritoneal layer was shown to shorten times to flatus ( p =0.016) and times to BM ( p =0.011) in one randomized controlled study ( n =200). Conclusions The incidence/definition of POI after RC is highly variable. An improved reporting strategy is needed to identify true incidence and risk factors, and to guide future research for both potential preventive and therapeutic interventions.
Genetic differentiation among populations of a Hispaniolan trunk anole that exhibit geographical variation in dewlap colour

Long neglected by classic island biogeographical theory, speciation within and among islands is increasingly recognized as a major contributor to insular diversity. Although the factors responsible for island speciation remain poorly understood, this process appears critically dependent on geographical variation and speciation in allopatry or parapatry. Here, we investigate geographical variation and speciation in a complex of Hispaniolan trunk anoles (Anolis distichus), where populations with strikingly distinct dewlap colours and patterns correspond with deeply divergent mtDNA structure. Using a multilocus, population-level analysis, we investigate whether these phenotypically and mitochondrially distinct populations exhibit the type of nuclear differentiation expected among species or incipient species. Along a transect that extends across a recently recessed marine barrier, our results are consistent with the persistence of an abrupt phenotypic and mitochondrial transition following secondary contact, in spite of little or no evidence for a reduction in nuclear gene flow. Along a second transect extending across a steep environmental gradient, our phenotypic and microsatellite data suggest a sharp genetic break with little or no admixture, whereas mtDNA recovers a signature of extensive unidirectional introgression. Together, these results are consistent with previous studies of Lesser Antillean anoles, suggesting that allopatric divergence alone is insufficient for speciation, whereas reduced gene flow and partial reproductive isolation may accumulate in the presence of ecological gradients.
The Role of Curcumin in Modulating Colonic Microbiota During Colitis and Colon Cancer Prevention.

Background Intestinal microbiota influences the progression of colitis-associated colorectal cancer. With diet being a key determinant of the gut microbial ecology, dietary interventions are an attractive avenue for the prevention of colitis-associated colorectal cancer. Curcumin is the most active constituent of the ground rhizome of the Curcuma longa plant, which has been demonstrated to have anti-inflammatory, antioxidative, and antiproliferative properties. Methods Il10 mice on 129/SvEv background were used as a model of colitis-associated colorectal cancer. Starting at 10 weeks of age, wild-type or Il10 mice received 6 weekly intraperitoneal injections of azoxymethane (AOM) or phosphate-buffered saline (PBS) and were started on either a control or a curcumin-supplemented diet. Stools were collected every 4 weeks for microbial community analysis. Mice were killed at 30 weeks of age. Results Curcumin-supplemented diet increased survival, decreased colon weight/length ratio, and, at 0.5%, entirely eliminated tumor burden. Although colonic histology indicated improvement with curcumin, no effects of mucosal immune responses have been observed in PBS/Il10 mice and limited effects were seen in AOM/Il10 mice. In wild-type and in Il10 mice, curcumin increased bacterial richness, prevented age-related decrease in alpha diversity, increased the relative abundance of Lactobacillales, and decreased Coriobacterales order. Taxonomic profile of AOM/Il10 mice receiving curcumin was more similar to those of wild-type mice than those fed control diet. Conclusions In AOM/Il10 model, curcumin reduced or eliminated colonic tumor burden with limited effects on mucosal immune responses. The beneficial effect of curcumin on tumorigenesis was associated with the maintenance of a more diverse colonic microbial ecology.
Evolution of pharyngeal behaviors and neuronal functions in free-living soil nematodes.

SUMMARY To explore the use of Caenorhabditis elegans and related nematodes for studying behavioral evolution, we conducted a comparative study of pharyngeal behaviors and neuronal regulation in free-living soil nematodes. The pharynx is divided into three parts: corpus, isthmus and terminal bulb, and pharyngeal behaviors consist of stereotyped patterns of two motions: pumping and peristalsis. Based on an outgroup species, Teratocephalus lirellus , the ancestral pattern of pharyngeal behaviors consisted of corpus pumping, isthmus peristalsis and terminal bulb pumping, each occurring independently. Whereas corpus pumping remained largely conserved, isthmus and terminal bulb behaviors evolved extensively from the ancestral pattern in the four major free-living soil nematode families. In the Rhabditidae family, which includes Caenorhabditis elegans , the anterior isthmus switched from peristalsis to pumping, and anterior isthmus and terminal bulb pumping became coupled to corpus pumping. In the Diplogasteridae family, the terminal bulb switched from pumping to peristalsis, and isthmus and terminal bulb became coupled for peristalsis. In the Cephalobidae family, isthmus peristalsis and terminal bulb pumping became coupled. And in the Panagrolaimidae family, the posterior isthmus switched from peristalsis to pumping. Along with these behavioral changes, we also found differences in the neuronal regulation of isthmus and terminal bulb behaviors. M2, a neuron that has no detectable function in C. elegans , stimulated anterior isthmus peristalsis in the Panagrolaimidae. Further, M4 was an important excitatory neuron in each family, but its exact downstream function varied between stimulation of posterior isthmus peristalsis in the Rhabditidae, isthmus/terminal bulb peristalsis in the Diplogasteridae, isthmus peristalsis and terminal bulb pumping in the Cephalobidae, and posterior isthmus/terminal bulb pumping in the Panagrolaimidae. In the Rhabditidae family, although M4 normally has no effect on the terminal bulb, we found that M4 can stimulate the terminal bulb in C. elegans if the Ca 2+ -activated K + channel SLO-1 is inactivated. C. elegans slo-1 mutants have generally increased neurotransmission, and in slo-1 mutants we found novel electropharyngeogram signals and increased pumping rates that suggested activation of M4-terminal bulb synapses. Thus, we suggest that the lack of M4-terminal bulb stimulations in C. elegans and the Rhabditidae family evolved by changes in synaptic transmission. Altogether, we found behavioral and neuronal differences in the isthmus and terminal bulb of free-living soil nematodes, and we examined potential underlying mechanisms of one aspect of M4 evolution. Our results suggest the utility of Caenorhabditis elegans and related nematodes for studying behavioral evolution.