cssi/SciSciGPT-SciSciNet huggingface dataset:
Small efficient scale as a foundation for Walrasian equilibrium

Publisher Summary This chapter presents small efficient scale as a foundation for Walrasian equilibrium. The set of aggregate technological possibilities for the economy is obtained by summing the production sets of a very large number of productive units, interpreted as firms. These units are most efficient when their output is small (infinitesimal) relative to the demand, and the classical case of U-shaped average cost is admitted in the analysis. Moreover, because efficient scale is small, firms have only an infinitesimal effect on price when confined to the region in which they make positive profit. This enables one to capture the notion that the demand curve appears flat to a firm, while at the same time demand price may change substantially with substantial changes in aggregate quantity. The mass of firms active in an equilibrium is determined by the conditions of supply and demand. Small changes in aggregate demand will typically change the list of firms which are present in an equilibrium. Because changes in taste cause some firms to leave the market and others to enter, and because there are usually firms on the margin of entry, entry plays an important role in the explanation of value.
Bisphosphonate Treatment of Tumor-Induced Hypercalcemia in a Toddler: Case Report and Review of Related Literature

Objective: To describe the initial manifestations and treatment of parathyroid hormone-related peptide (PTH-rP)-induced hypercalcemia in a toddler with a malignant rhabdoid tumor.Methods: We report...
New detection schemes in liquid chromatography

A micropolarimeter interfaced to a liquid chromatograph is shown to be suitable for selective monitoring of the optically-active components in complex samples. When an optically-active eluent is used, indirect determination of even optically-inactive materials is possible, down to the level of 10 ng of an injected component. If a second chromatogram is obtained using the racemic analogue of the optically-active eluent, quantitation can be achieved without standards and without prior analyte identification. This concept is also applicable to the refractive index detector, the absorption detector and the conductivity detector in the special case of ion chromatography, and the ultrasonic detector in gas chromatography.
Systemic Activin signaling independently regulates sugar homeostasis, cellular metabolism, and pH balance in Drosophila melanogaster

The ability to maintain cellular and physiological metabolic homeostasis is key for the survival of multicellular organisms in changing environmental conditions. However, our understanding of extracellular signaling pathways that modulate metabolic processes remains limited. In this study we show that the Activin-like ligand Dawdle (Daw) is a major regulator of systemic metabolic homeostasis and cellular metabolism in Drosophila. We find that loss of canonical Smad signaling downstream of Daw leads to defects in sugar and systemic pH homeostasis. Although Daw regulates sugar homeostasis by positively influencing insulin release, we find that the effect of Daw on pH balance is independent of its role in insulin signaling and is caused by accumulation of organic acids that are primarily tricarboxylic acid (TCA) cycle intermediates. RNA sequencing reveals that a number of TCA cycle enzymes and nuclear-encoded mitochondrial genes including genes involved in oxidative phosphorylation and β-oxidation are up-regulated in the daw mutants, indicating either a direct or indirect role of Daw in regulating these genes. These findings establish Activin signaling as a major metabolic regulator and uncover a functional link between TGF-β signaling, insulin signaling, and metabolism in Drosophila.
Autoimmunity and Allergy: Regulatory Implications

Although allergies and autoimmunity are among the most serious adverse reactions associated with drug therapy, there are few truly useful nonclinical models for predicting these phenomena. Drug-associated allergies or autoimmune reactions are usually observed either in clinical trials or during postmarketing surveillance. There are no general regulatory requirements in the United States concerning nonclinical evaluation of drugs for sensitizing potential. Drugs intended for topical application are usually evaluated for skin sensitizing potential and assays for this phenomenon are somewhat predictive and useful. If a drug is demonstrated to have skin-sensitizing potential, it is likely that it could produce other types of sensitization as well. Particular classes of drugs should be evaluated based on known mechanisms of sensitization or antigenicity (eg, proteins, highly reactive small molecular weight molecules, photoreactive compounds, β-lactams, etc.). There are no useful models for predicting autoimmun...
Glioblastoma, transforming growth factor-β, and Candida meningitis: A potential link

The development of Candida meningitis in a patient following partial resection of a glioblastoma raised suspicion that transforming growth factor (TGF-beta), an immunosuppressive cytokine known to be produced by this tumor, would be elevated in his cerebrospinal fluid (CSF). By using a highly specific bioassay, the concentration of TGF-beta was found to be 609 pg/mL, which was 10-fold greater than the mean CSF TGF-beta value in control subjects with no neurologic disease. Increased CSF TGF-beta levels were also detected in patients with other central nervous system (CNS) diseases: malignancies and AIDS dementia complex. These findings suggest that TGF-beta may play an immunopathogenetic role in the CNS.
Autologous stem cell transplant in a patient with Down syndrome and relapsed Hodgkin lymphoma

Children with Down syndrome (DS) are at increased risk for the development of acute leukemia but they rarely develop other hematologic malignancies or solid tumors. Despite aggressive supportive care, DS patients have increased risk of treatment related morbidity and mortality compared to other children. There are few reported cases of Hodgkin disease in children with DS, and no reported cases of successful therapy for patients with relapsed disease. We report on a child with DS and relapsed Hodgkin disease who was successfully treated with high-dose chemotherapy and autologous stem cell transplant. Pediatr Blood Cancer 2009; 53:1327–1328. © 2009 Wiley-Liss, Inc.
Effects of repeated exposure to nitric acid vapor and ozone on respiratory tract clearance in the rat

AbstractThis study assessed the effects of repeated exposure to environmentally realistic levels of two urban air pollutants—nitric acid vapor (HNO3) and ozone (O3)—on tracer particle clearance from the rat xrespiratory tract The measurement of particle clearance efficiency is important because failure of this function could contribute to a buildup of foreign matter in the respiratory tract. Separate groups of rats (30 rats per group) were exposed nose-only for 4 h/day, 3 days/wk (a surrogate for an air pollution episode) for 40 wk to 4 atmospheres: purified air; 0.15 ppm 03; 50 μg/m3 HNO3; and 0.15 ppm O3 + 50 μg/m3 HNO3 At 4 wk prior to the end of the exposure, the rats inhaled radiolabeled tracer particles nose-only for 30 min. A clearance measurement protocol was then followed to estimate the rates of early and late clearance. Early (presumably upper respiratory tract) clearance was monitored during the 48 h following tracer deposition by the analysis of radioactivity excreted in the feces, while late...
Philosophy's Roles in Afrocentric Education.

Should philosophy be introduced as a formal subject to kindergarten through 12th grade students in Afrocentric schools? U.S. public education's aversion to philosophy is so pervasive that Afrocentr...
Influence of averaging interval on shear velocity estimates for aeolian transport modeling

Abstract Recent investigations of aeolian transport have focused on increasingly short time scales because of growing recognition that wind unsteadiness is a major factor in the dynamics of sediment transport. However, the statistical reliability of shear velocity ( u * ) estimates becomes increasingly uncertain as averaging interval is decreased. This study provides an empirical assessment of the influence of averaging interval on the reliability of u * estimates. The data consist of 15-min wind-speed profiles (1 Hz sampling) collected at four coastal sites. Each profile was subdivided into progressively shorter fixed-length time intervals, and estimates of u * and the 95% confidence interval for u * were determined for each time-block using standard statistical techniques. The logarithmic model accurately represents the measured wind-speed profiles, even with relatively brief averaging intervals. Mean r 2 values remain robust down to block lengths as short as 10–20 s, typically retaining better than 98% of the r 2 value found for the full-length data sets. Fewer than 2% of the individual 10-s blocks had r 2 values less than 0.9. However, mean confidence intervals typically expanded by 70–80% of the full-record value as block length decreased from 900 to 10 s. For highly log-linear profiles, this amounted to an absolute increase from about ±8% to only ±14% of u * , so that the additional information gained through the use of shorter averaging intervals may outweigh the increase in statistical uncertainty. Nevertheless, given that rates of aeolian transport are generally modeled as a function of u * 3 , this increase in uncertainty may be significant for transport modeling. Thus, very short averaging intervals should be used with caution when predicting aeolian sediment flux. It is proposed that transport modeling should incorporate the shear velocity confidence interval as an indicator of the potential error associated with this source of uncertainty.
Density Effects on Subyearling Fall Chinook Salmon During Hatchery Rearing in Raceways with Oxygen Supplementation and After Release

Abstract To determine the effects of hatchery rearing density on fall Chinook Salmon Oncorhynchus tshawytscha released as age-0 subyearlings, we experimentally reared fish at densities of 200,000, 300,000 and 400,000 fish per raceway in Michigan-style raceways that employ oxygen supplementation to achieve high density rearing. The study was conducted for two release years at a maximum raceway density of 52.3 kg/m3 and a maximum loading of 0.92 kg·L−1·min−1. At the end of hatchery rearing there was no significant difference in weight in either release year and Fulton's condition factor was similar in the first year. In the second release year condition factors were significantly different; the low-density group had significantly lower values and the high-density group had significantly higher values. Following release into the Umatilla River, Oregon, out-migration survival and travel time to John Day Dam on the Columbia River was monitored by using passive integrated transponder tags in a subsample of each...
Vibrational spectra of tetraethylaluminate anions

Abstract The vibrational spectra of LiAlEt 4 and NaAlEt 4 are reported. It is concluded that the former has D 24 symmetry and that the latter has T d symmetry.
Suppression of luteinizing hormone release by the α1-adrenergic receptor antagonist prazosin in the ovariectomized female rhesus monkey.

The effects of adrenergic antagonists on LH release were examined in ovariectomized female rhesus monkeys implanted with indwelling jugular catheters. While the α2-adrenergic antagonist rauwolscine and the vehicle were without effect, the α1-antagonist prazosin suppressed LH release. In 5 of the 8 monkeys tested, LH pulses were completely arrested; in the remaining 3 monkeys, small LH pulses were detectable after the administration of 0.2 mg/kg prazosin. In a second series of experiments, the effects of three different doses of prazosin were examined. Doses of 0.1 mg/kg and 0.4 mg/kg suppressed LH release in a manner indistinguishable from that of the 0.2 mg/kg dose. Finally, the ability of the pituitary to respond to a bolus of LHRH during the prazosin-induced suppression was tested. In all 6 animals, the injection of LHRH during the time when LH was suppressed by prazosin resulted in a marked increase in LH release. These results indicate 1) that α1-adrenergic receptors but not α2 receptors are important for pulsatile LH secretion, 2) that varying the dose of prazosin administered does not alter the effect of the drug or LH release within the range of doses tested, and 3) the pituitary is able to respond to LHRH with an increase in LH release during the prazosin-induced suppression period.
Distribution of orexin/hypocretin immunoreactivity in the nervous system of the green Treefrog, Hyla cinerea

We examined the distribution of orexin/hypocretin immunoreactive neurons and projections throughout the brain of the green treefrog (Hyla cinerea). Orexin A and B neurons were located in a single population centered on the suprachiasmatic nucleus. Orexin A and B fibers were visible across the brain, with the highest density within the preoptic area and hypothalamus. Our data suggest different distributions of orexin neurons but not projections between families of amphibians.
Institutional influences on business model choice by new ventures in the microgenerated energy industry

Abstract Business model choice plays an important source of competitive advantage for new ventures in the microgeneration sector. Yet, existing literature focuses on strategic management of internal resources as the constraints in this choice process. In the energy sector, external factors may be at least as influential in shaping these business models. This paper examines the roles of politico-institutional and socio-institutional dynamics in the choice of business models for microgeneration ventures. Business models have traditionally been viewed as constructions of the internal values, strategies, and resources of organizations. But, this perspective overlooks the role that external forces have on these models, particularly in more highly institutionalized contexts like microgeneration. When these factors are introduced into the existing framework for business model choice, the business model based less on firm decision-making and more about variables that exist within national innovation systems and political structure, local socio-technological conditions, and cognitive abilities of the entrepreneur and corresponding stakeholders.
Complementary and alternative medicine for perinatal depression.

Abstract Introduction Perinatal Major Depressive Disorder (MDD) is common and poses particular treatment dilemmas. Complementary and Alternative Medicine (CAM) treatments are widely used, accessible, and understudied for well-defined psychiatric indications. Women are more likely than men to both suffer from MDD and use CAM. Methods A PubMed/Medline search was conducted to assess the evidence base for commonly utilized CAM treatments, MDD, and perinatal depression. Results Among CAM treatments, omega-3 fatty acids have received the most specific study in terms of epidemiological, preclinical, and clinical research for perinatal depression. Three randomized placebo-controlled trials have been conducted in which investigators assessed omega-3 fatty acids vs. placebo for perinatal depression, with conflicting results. CAM interventions that can be easily added to a treatment plan with little risk and general health benefits for most women include omega-3 fatty acids, exercise, and folate, although data are insufficient at this time to recommend any of these as monotherapy for perinatal depression. S-adenosyl-methionine (SAMe) and bright light therapy may be reasonable to consider based on the evidence in MDD. St. John's Wort requires further study with regard to safety in pregnancy, and drug interactions can be a potential problem. Discussion Further study is required to elucidate the role of CAM treatments for perinatal depression, and the clinical context of perinatal depression requires safe, effective, and accessible treatment options.
Distributed neural computations for embedded sensor networks

ABSTRACT Wireless sensing technologies have recently emerged as an inex pensive and robust method of data collection in a variety of structural monitoring applications. In comparison with cabled monitoring systems, wi reless systems offer low-cost and low-power communication between a network of sensing devices. Wireless sensing networks possess embedded data processing capabilities which allow fo r data processing directly at the sensor, thereby eliminating the need for the transmission of raw data. In this study, the Volterra/Weiner neural network (VWNN), a powerful modeling tool for non-linear hysteretic behavior, is decentralized for embedment in a network of wirele ss sensors so as to take advantage of each sensors processing capabilities. The VWNN was chosen for modeling nonlinear dynamic systems because its architecture is computationally efficient and allows computational tasks to be decomposed for parallel execution. In the algorithm, each sensor collects it own data and performs a seri es of calculations. It then shares its resulting calculations with every other sensor in the network, while the other sensors are simultaneously exchanging their information. Because resource conservation is important in embedded sensor design, the data is pruned wh erever possible to eliminate excessive communication between sensors. Once a sensor has its required data, it continues its calculations and computes a prediction of the system acceleration. The VWNN is embedded in the computational core of the Narada wireless sensor node for on-line execution. Data generated by a steel framed structure excited by seismic ground motions is used for validation of the embedded VWNN model. Keywords: distributed computing, embedded neural networks, wireless sensor networks, structural health monitoring
Dynamics of soldering reactions: Microscopic observations

This paper provides a summary of some in situ, high-resolution studies of solder spreading reactions on microelectronic circuit metallizations. Experiments are described that focus on the use of the environmental scanning electron microscope, or ESEM. Those experiments have been complemented by studies using optical hot-stage microscopy and have been supplemented by additional analytical tools such as energy dispersive X-ray microanalysis, Auger and ESCA to evaluate chemical processes. Two general results from dynamic scanning electron microscope observations are that (1) molten solder alloys undergo a segregation process during spreading in which a “precursor” film spreads in advance of the bulk solder and (2) the spreading front, which may be enriched in Sn from Pb-Sn or Bi-Sn solders, or In from Pb-In solders, spreads along high-reactivity features of the metallization surface as a reacting “precursor” film. A third observation from these tests is that, in unconfined geometries, the reactive metallization, if not sufficiently thick, can be dissolved by the solder before wetting is complete, leading to dewetting of the solder. Both the kinetics and extent of spreading of these films and the relationship of these phenomena to the commonly measured contact angle and wetting forces are currently being examined by a range of complementary techniques. Information gathered in these studies shows that process temperature as well as composition, reactivity, and relative amounts of the solder and metallization species should all be factors of interest to the those responsible for control of soldering processes. © 1993 Wiley-Liss, Inc.
PHOTOINDUCED ELECTRON TRANSFER

Abstract— Given the pre-eminent roles of photoinduced electron transfer and energy transfer as primary events in photobiology, it is incumbent on practitioners of the science to understand those principles which govern these elementary events. Recent developments in both theory and experiment on photoinduced electron transfer have allowed for important insights into understanding the factors governing such steps. For example, shown in Fig. 1 is a representation of the positions of the chromophores in the photosynthetic reaction center of Rhodopseudomonas sphaeroides, as determined from crystallographic measurements (Chang et al., 1986), showing that its three dimensional arrangement within an intact membrane is analogous to that observed earlier in Rhodopseudomonas viridis (Deisenhofer et al., 1984). In both systems, the critical event of photosynthesis is the transfer of an electron from the photoexcited special pair of bacteriochlorophylls located at the top via the pheophytin at the far right to the quinone at the bottom which acts as an ultimate repository for the separated charge. Of great importance is a determination of those factors which govern the efficiency and the rate of electron transfer through this photoinduced cascade and a better understanding of how this fixed, prearranged structure maximizes the efficiency of photochemical energy storage. Although the reaction center represents nature's most graphic and most detailed connection between the experimental and theoretical models of photoinduced electron transfer, much of the physical insight into this process has been developed on simpler organic molecules. Rattier than focusing on the details of photosynthesis, this article will concentrate on recent developments in model systems which evaluate the relative importance of factors influencing the efficiency and rates of excited state induced electron transfer. We introduce these concepts at a level appropriate for the scientifically literate biologist who has not heretofore been concerned with such details. Since this is an overview article, few citations of the original literature will appear, and the interested reader should refer to any number of excellent topical reviews which consider specific aspects of photoinduced electron transfer for further investigation (Fox and Chanon, 1989; Pac and Oshitani, 1989).
Quercetin Increases the Severity of Estradiol-Induced Tumorigenesis in Hamster Kidney

Catechol estrogens have been postulated to mediate estradiol-induced kidney tumorigenesis in Syrian hamsters. As part of an examination of this postulate, we studied the influence of quercetin, a polyphenolic flavonoid, on the incidence and severity of estrogen-induced kidney tumors, on the metabolic activation of estradiol to catechol estrogens, and on the inactivation of catechol estrogens by catechol-O-methyltransferase-mediated O-methylation. None of the hamsters treated with 0.3 or 3% quercetin in the diet for 5.7 or 6.5 months, respectively, developed tumors, whereas all animals treated with estradiol developed kidney tumors. The coadministration of estradiol plus 3% quercetin significantly (p < 0.05) increased the mean number of large tumor nodules and the incidence of abdominal metastases over values obtained with hormone treatment alone. The coadministration of estradiol plus 0.3 or 3% quercetin for 16 days increased renal NADPH-dependent estradiol-4- but not estradiol-2-hydroxylase activities by 91 or 73%, respectively, over values obtained with hormone treatment alone. In vitro, quercetin and its structural analog, fisetin, strongly inhibited the catechol-O-methyltransferase-catalyzed O-methylation of 60 microM 4-hydroxyestradiol, with IC50 values of approximately 2-4 microM. Kinetic analyses of the enzyme inhibition by quercetin and fisetin revealed a mixed-type of inhibition (competitive plus non-competitive). Combined treatment of estradiol plus 3% quercetin decreased the rates of kidney catechol-O-methyltransferase-catalyzed O-methylation of 2- and 4-hydroxyestradiol by 34 and 22%, respectively, from values obtained with hormone treatment alone. Rates of hamster liver and kidney microsome-mediated estrogen quinone formation and quinone reduction (redox cycling) in estradiol plus 3% quercetin-treated hamsters were not markedly altered compared to values obtained in estradiol-treated animals. It is concluded that increased rates of formation of 4-hydroxyestradiol combined with an inhibition of the inactivation of this catechol estrogen by catechol-O-methyltransferase may result in elevated levels of this estrogen metabolite, specifically in the hamster kidney, where it may undergo metabolic redox cycling and generate potentially mutagenic free radicals. Thus, the potentiation by quercetin of estradiol-induced tumorigenesis in hamster kidney supports a role of 4-hydroxyestradiol in estrogen-induced carcinogenesis in this species.
Direct scanning active enzyme gel chromatography with halted flow for detecting molecular weight heterogeneity of active enzymes

Abstract As an extension of the method of scanning active enzyme chromatography we have introduced the option of halting flow while the enzyme is still present on the column. Once the flow has been halted, continuous monitoring of the absorbancy profile provides information on the relative distribution of the enzyme activity. When the baseline is relatively stable, one can detect very low levels of enzyme activity and thus monitor for the presence of small amounts of active enzyme of molecular weight different from that of the predominant form. This gives a significant improvement over regular active enzyme chromatography in the qualitative detection of molecular weight heterogeneity, by in effect reducing the noise level of the experiment. The method has been applied to several systems including aldolase from rabbit muscle, pyruvate dehydrogenase, and α-ketoglutarate dehydrogenase of bovine heart and hexokinase and glucose-6-phosphate dehydrogenase from yeast.
Challenges in assessing the potential allergenicity of biotechnology products

Regulatory guidelines for assessing the safety of new food crops developed using biotechnology were published in the early 1990s, before the introduction of genetically modified (GM) crops. Many GM crops are now widely adopted as 77% of global soybean and 26% of maize production is from GM varieties. The early safety assessment guidelines seem to work as there are no proven cases of harm from these products. The greatest potential risk of food allergy would be the transfer of a gene encoding an allergen or protein sufficiently identical to an allergen to a different food crop so that unexpected reactions might occur upon ingestion. These risks can be evaluated using sera from subjects allergic to the source or with a sequence matched to an allergen based on FASTA or BLASTP. Some potential risk is also possible due to de novo sensitization as nearly every food may cause occasional allergies, yet only a few foods and proteins present great risk. The current paradigm considers stability of the protein in pepsin under fixed conditions, abundance of the protein in foods and the potential impact of heating and processing, features common to some major allergens. Those methods are not fully predictive and will likely be improved through experience. However, proposed revisions by the European Food Safety Authority (EFSA) as well as demands from some regulators to include the use of short-amino acid sequence matches, animal models and evaluation of potential changes in endogenous allergen expression using proteomics approaches could reduce the effectiveness of the assessment. The value of new tests should be rigorously tested. It is clear that absolute safety is not possible and that demands for these tests have never been applied to new crop varieties derived through inter-specific hybridization, mutagenesis or the introduction of a whole new food crop.
Transfer in part-whole and whole-part free recall: A comparative evaluation of theories

Two experiments, involving part-whole and whole-part transfer respectively, investigated the adequacy of two organizational and two list discrimination accounts of transfer. The organizational accounts were those of Tulving (1966) and of Novinski (1972) , while the list discrimination accounts were those of Slamecka, Moore, and Carey (1972) and of Anderson and Bower (1972) . In each transfer task, 45 subjects were instructed to recall all words from both initial and transfer lists, indicating a list membership for each word and a confidence rating for each list assignment. A list-identification task was administered at the end. Recall and list-identification were scored for overall proportions of types and tokens, and for proportions of tokens recalled from each of three list partitions. Analyses of recall and organizational measures failed to support either organizational interpretation of transfer. Patterns of recall, list-identification, and confidence ratings were consistent with the theory of Anderson and Bower, but not with the response-withholding theory of Slamecka, Moore, and Carey.
On a Few of Ann and Rud Turnbull's Many Contributions as Public Intellectuals

Abstract This article reflects on a few of the major intellectual contributions Ann and Rud Turnbull and their colleagues at the Beach Center on Family and Disability have made to their academic fi...
Optimization of Three-Dimensional Micropost Microcavities for Cavity Quantum Electrodynamics

This paper presents a detailed analysis, based on the first-principles finite-difference time-domain method, of the resonant frequency, quality factor (Q), mode volume (V), and radiation pattern of the fundamental (HE11) mode in a three-dimensional distributed-Bragg-reflector (DBR) micropost microcavity. By treating this structure as a one-dimensional cylindrical photonic crystal containing a single defect, we are able to push the limits of Q/V beyond those achievable by standard micropost designs, based on the simple rules established for planar DBR microcavities. We show that some of the rules that work well for designing large-diameter microposts (e.g., high-refractive-index contrast) fail to provide high-quality cavities with small diameters. By tuning the thicknesses of mirror layers and the spacer, the number of mirror pairs, the refractive indices of high- and low-refractive index regions, and the cavity diameter, we are able to achieve Q as high as 10(4), together with a mode volume of 1.6 cubic wavelengths of light in the high-refractive-index material. The combination of high Q and small V makes these structures promising candidates for the observation of such cavity-quantum-electrodynamics phenomena as strong coupling between a quantum dot and the cavity field, and single-quantum-dot lasing.
Opsonin and leukophilic γ globulin in chronically splenectomised rats with and without heterotropic autotransplanted splenic tissue

Opsonin and leukophilic γ globulin in chronically splenectomised rats with and without heterotropic autotransplanted splenic tissue
Synthesis and Conformational Analysis of 6-C-Methyl-Substituted 2-Acetamido-2-deoxy-β-d-glucopyranosyl Mono- and Disaccharides

Several 6-C-substituted 2-acetamido-2-deoxy-beta-D-glucopyranosides (beta-D-GlcNAc monosaccharides 1a-3a and 1,4-linked disaccharides 1b-3b) were studied by solution NMR spectroscopy. Conformational analysis of the (6S)- and (6R)-C-methyl-substituted beta-d-GlcNAc monosaccharides indicates that the stereodefined methyl groups impose predictable conformational biases on the exocyclic C-5-C-6 bond, as determined by (1)H-(1)H and (13)C-(1)H coupling constants. Variable-temperature NMR experiments in methanol-d(4) were performed to determine DeltaDeltaH and DeltaDeltaS values derived from the two lowest energy conformers. These indicate that while the influence of 6-C-methyl substitution on conformational enthalpy is in accord with the classic principles of steric interactions, conformational preference in solution can also be strongly affected by other factors such as solvent-solute interactions and solvent reorganization.
Electrical and Optical Properties of Polysilicon Sheets for Photovoltaic Devices Grown from Powder

In a search for low-cost and high efficiency solar cell manufacturing, several techniques of growing thin silicon sheets from powder have been adopted, such as: plasma spraying on various substrates, zone-melting using incoherent focussed light as heat source, and low-angle horizontal pulling of thin ribbon over the melted tin-lead support. Undoped, and n- and p-type silicon powders of various grain sizes have been used as starting materials, with pure graphite, quartz, or low-cost ceramics serving as temporary or permanent substrates. N + /p + /n junctions, and back surface fields were formed by implanting PF 5 and BF 3 + ions in a glow discharge ion implanter at ultralow energies (less than 1 keg) and high total ion doses. Ion induced damage was annealed by RTP in the incoherent light furnace at temperatures as low as 700°C. Structural and optoelectronic properties of as-grown and processed thin polysilicon sheets were determined by Raman spectroscopy, spectral response, and electrical transport measurements. A sharp peak at 520 cm −1 in the Raman spectra, associated with TO ((Г) phonons, indicated a good crystallinity of polysilicon sheets. High values of short-circuit currents, and an almost flat spectral response down to 400 nm, without intentionally applying a surface passivating oxide, illustrate the advantage of the applied novel technologies.
Distributed algorithms for formation of geometric patterns with many mobile robots

We discuss a method for controlling a group of mobile robots in a distributed manner. The method is distributed in the sense that all robots, or most of the robots in some cases, plan their motion individually based upon the given goal of the group and the observed positions of other robots. We illustrate the method by showing how a large number of robots can form an approximation of a circle, a simple polygon, or a line segment in the plane. We also show how the robots can distribute themselves nearly uniformly within a circle or a convex polygon in the plane. Finally, we show how the robots can be divided into two or more groups. It turns out that in many cases most robots execute an identical, simple algorithm. The performance of the method is demonstrated by simulation. © 1996 John Wiley & Sons, Inc.
Methods of Series Analysis. I. Comparison of Current Methods Used in the Theory of Critical Phenomena

We survey the principal types of methods of series analysis which have been used in the study of critical phenomena with a view to determining their accuracy and applicability to the treatment of the critical-point singularities. These methods include the ratio method and its variants, such as the Neville-table method; the Pad\'e-approximant procedures; and the procedures based on the generalized-Polya theorems of Thompson et al. We show that the actual procedures of Thompson et al. are mathematically equivalent to certain of the Pad\'e-approximant procedures. We give a general error analysis for the series-analysis procedures and derive a relation between the expected magnitude of the errors in the parameters of $A{(1\ensuremath{-}yx)}^{\ensuremath{-}\ensuremath{\gamma}}$, namely, $\ensuremath{\Delta}y:\ensuremath{\Delta}\ensuremath{\gamma}:\ensuremath{\Delta}A$ as $1:J:J \mathrm{ln}J$, where $J$ is the order of the last term of the series analyzed. This relation is briefly illustrated by numerical data. We further give procedures for establishing estimates of the magnitude of errors in the parameters that have the same type of validity as those commonly used to determine the accuracy of a truncated Taylor series. We discuss the commonly occurring but anomalous case of "defects" (errant close pole and zero) in Pad\'e-approximant procedures. We show them to be related to Pad\'e's block structure of the approximant table and emphasize the artificial nature of the apparently rapid convergence that they cause. By numerical investigation of many test functions, similar in structure to those believed to appear in problems of critical phenomena, we have illustrated the following conclusions. First, for series where there is only a simple algebraic singularity, closer to the origin and well separated from any other singularity, the ratio method, perhaps with Neville-table improvement, is the most effective procedure. Second, for series where there are interfering singularities close to the one considered, or where there are singularities either closer than or nearly at the same distance from the origin as the one considered, the Pad\'e procedures are best. Finally, for not exactly representable singularity structures of the type just decscribed, the convergence of even the Pad\'e-approximant procedures are significantly slowed. None of the general methods described does a very impressive job in computing the $\ensuremath{\gamma}$ value if the function is in fact of the form $A{(1\ensuremath{-}yx)}^{\ensuremath{-}\ensuremath{\gamma}}\mathrm{ln}|1\ensuremath{-}yx|$.
Enhanced pulmonary inflammation following experimental intracerebral hemorrhage.

Abstract The association between brain damage and respiratory dysfunction has been recognized although mechanistic link between the two is still poorly defined. Intracerebral hemorrhage is accompanied by brain injury, stroke, and parenchymal hematoma formation with surrounding inflammation. Increase intracranial pressure as a result of intracerebral hemorrhage may promote localized activation of cytokines and coagulation system including tissue factor release. However, whether intracerebral hemorrhage triggers inflammation in noncerebral organs has not been elucidated. The aim of the present study was to examine the impact of intracerebral hemorrhage on lung inflammatory response. Intracerebral hemorrhage was induced by stereotaxic intrastriatal administration of bacterial collagenase. Expression of intracellular adhesion molecule-1 (ICAM-1), I K B-α, tissue factor, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) was evaluated by Western blot analysis. Our results revealed that intracerebral hemorrhage upregulated expression of ICAM-1 and tissue factor in both brain and lung, whereas it enhanced TNF-α and IL-1β mainly in brain within 6 and 24 h of the brain injury. Levels of I K B-α remained unchanged in brain and lung tissues. Appearance of inflammatory markers in the lung was accompanied by morphological pulmonary damage. These data suggest that intracerebral hemorrhage may trigger acute inflammatory response in both brain and lung.
Duplex scan characteristics of bypass grafts to mesenteric arteries

Background Mesenteric bypass grafts may be followed postoperatively with duplex scanning. It is unknown, however, if duplex-derived velocity measurements vary over time or if the type of procedure (antegrade vs retrograde) and the caliber of graft affect velocity measurements. The purpose of this study was to characterize duplex findings in mesenteric bypass grafts with respect to the type of revascularization, graft caliber, and changes over time. This study also sought to identify duplex characteristics that could predict subsequent graft failure. Methods Duplex examinations of mesenteric bypass grafts were reviewed. Peak systolic velocities (PSV) from the inflow artery, proximal anastomosis, mid graft, distal anastomosis, and outflow arteries were analyzed with respect to timing of the examination (index study vs follow-up exam), inflow source, distal target, and graft diameter. The results were compared with analysis of variance ( P Results Fasting postoperative duplex scans were reviewed from 43 mesenteric bypass grafts in 38 patients (28 superior mesenteric artery [SMA] alone, 3 celiac alone, 5 celiac and SMA, 2 SMA and renal). A total of 167 duplex exams were analyzed (mean of 4.5 studies per patient; range, 1 to 14). Inflow artery velocities were significantly lower in antegrade vs retrograde configurations (93 ± 73 cm/s vs 154 ± 73 cm/s, P P = NS). An association between smaller graft diameter and higher mid-graft PSV was seen with univariate analysis ( P = .03), with a trend toward significance with multivariate analysis ( P = .06). In 18 bypass grafts where a follow-up examination was available >1 year (mean 38 ± 25 months) after the index postoperative exam, velocity did not significantly change over time. No duplex scan characteristics were predictive of graft thrombosis. Conclusion This is the first study, to our knowledge, to fully characterize duplex-derived flow velocities in mesenteric artery bypass grafts. Although surveillance duplex scans after mesenteric bypass procedures may be affected by graft diameter, they are not significantly affected by the choice of inflow artery. These data can serve as standards for postoperative surveillance of mesenteric bypass grafts.
Pressure Effects on Cholesterol and Lipid Synthesis by the Swimbladder of an Abyssal Coryphaenoides Species

SYNOPSIS. The swimbladder gas gland is recognized as a cholesterol synthesis site in abyssal rattail fishes, Coryphaenoides sp. (from 2000 m depth), and Galapagos Islands surface fish, Orthopristis forbesi, Seriola mazatlana , and Sphoeroides annulatus . This relates to high levels of cholesterol in the gas gland (up to 21% of lipid) and high cholesterol levels in the fatty swimbladder interior (up to 49% of lipid). The gas gland has more protein (45.4%) than the internal fatty mass (18%). Lipids synthesized include phospholipids and triglycerides in 2:1 ratio in the gas gland and 1:2 ratio in the liver. Deep fish have fatty livers (66%) compared to shallow fish (28%). Shallow fish incorporated five times as much acetate-l-14C into lipids as did deep fish, and seven to eight times as much acetate-l-14C into cholesterol. Pressure facilitation of cholesterol synthesis was observed in gas gland and liver of O. forbesi and Coryphaenoides , whereas total lipid synthesis was inhibited by higher pressures. Optimal acetate-l-14C incorporation into lipids occurred at 5000 psi and 2°C in Coryphaenoides ; it occurred at 14.7 psi and 15° in O. forbesi . These conditions closely approximate the environment of the fish.
Climate change policy: quantifying uncertainties for damages and optimal carbon taxes

Abstract Controversy surrounds climate change policy analyses because of uncertainties in climatic effects, impacts, mitigation costs and their distributions. Here we address uncertainties in impacts, and provide a method for quantitative estimation of the policy implications of such uncertainties. To calculate an “optimal” control rate or carbon tax a climate-economy model can be used on estimates of climate damages resulting from warming scenarios and several other key assumptions. The dynamic integrated climate-economy (DICE) model, in its original specification, suggested that an efficient policy for slowing global warming would incorporate only a relatively modest amount of abatement of greenhouse gas emissions, via the mechanism of a small (about $5 per ton initially) carbon tax. Here, the DICE model is reformulated to reflect several alternate published estimates and opinions of the possible damages from climatic change. Our analyses show that incorporating most of these alternate damage estimates into DICE results in a significantly more aggressive optimal policy than that suggested by the original model using a single damage function. In addition, statistical distributions of these damage estimates are constructed and used in a probabilistic analysis of optimal carbon tax rates, resulting in mostly much larger (but occasionally smaller) carbon taxes than those of DICE using point values of damage estimates. In view of the large uncertainties in estimates of climate damages, a probabilistic formulation that links many of the structural and data uncertainties and thus acknowledges the wide range of “optimal” policies is essential to policy analysis, since point values or “best guesses” deny policy makers the opportunity to consider low probability, but policy-relevant, outliers. Our presentation is offered as a prototypical example of a method to represent such uncertainties explicitly in an integrated assessment.
Classical conditioning of heart rate discriminations using subcortical electrical stimulation as conditioned and unconditioned stimuli

Abstract Heart rate (HR) discriminations were classically conditioned in rabbits by having electrical stimulation of one medial geniculate or dorsal lateral geniculate body, but not the contralateral structure, immediately followed by hypothalamic, subthalamic or midbrain electrical stimulation. The major findings were that: (a) HR discriminations were elicited to midbrain or diencephalic unconditioned stimuli (US); (b) larger HR discriminations were conditioned to diencephalic than to midbrain US stimulation; (c) in both the midbrain and diencephalon, US electrode placements were found which either elicited accelerative or decelerative HR conditioning; and, (d) in diencephalic and midbrain reticular formation, but not midbrain central grey US sites, a strong positive relationship was found between accelerative HR responses and diffuse movement.
Examining the role of emotion in suicidality: negative urgency as an amplifier of the relationship between components of the interpersonal-psychological theory of suicidal behavior and lifetime number of suicide attempts.

Abstract Joiner's (2005) interpersonal–psychological theory of suicidal behavior posits that an individual must exhibit elevations on three variables – perceived burdensomeness, thwarted belongingness, and the acquired capability for suicide – in order to enact lethal self-harm. Thus far, however, no research has examined the role of emotion in this process or whether the interaction of these three variables is more problematic for certain populations than for others. We sought to address these voids by examining the role of negative urgency as an amplifier of the relationship between the components of the theory and lifetime number of suicide attempts. Results indicated that the four-way interaction of negative urgency and the three components of the theory predicted lifetime number of suicide attempts, controlling for depression symptoms and sex. Additionally, the three-way interaction of the theory components significantly predicted lifetime number of suicide attempts in the full sample. Furthermore, for individuals with negative urgency scores at or above the median, the three-way interaction of the theory components significantly predicted lifetime number of suicide attempts whereas, for individuals with negative urgency scores below the median, the interaction was non-significant. These findings indicate that, although elevations on the three components of the theory may be dangerous for anyone, this is particularly true for individuals exhibiting high levels of negative urgency, as they might be more likely to quickly develop suicidal ideation and resort to painful self-harming behaviors while experiencing negative affective states.
Use of kinetic models to explore the role of base promoters on Ru/MgO ammonia synthesis catalysts

The kinetics of ammonia synthesis over unpromoted and Cs-, Ba-, and La-promoted Ru/MgO (∼2 wt%) were studied in a tubular reactor at 20.7 atm. The reaction over all of the catalysts was nearly first order in N2 and nearly zero order in NH3. However, the order of reaction in H2 was largely dependent on the choice of promoter, with Ba and La significantly reducing the inhibition by dihydrogen seen on Cs-promoted Ru/MgO. The turnover frequencies on Ba- and La-promoted Ru/MgO under stoichiometric conditions and 673 K were almost an order of magnitude greater than that on Cs-promoted Ru/MgO. Two kinetic models with optimized parameters were used to describe the outlet ammonia pressures determined experimentally both close to and far from equilibrium. Although Cs promotion of Ru lowered the activation barrier for N2 dissociation, the enthalpy of dihydrogen adsorption and therefore the H atom surface coverage increased. Thus, promotion of Ru catalysts with bases cannot be attributed solely to an effect on dinitrogen dissociation, which is the rate-determining step. Base promotion is a trade-off between lowering the activation barrier for N2 dissociation and increasing the competitive adsorption of H2. The coverages of nitrogen-containing species determined by an optimized kinetic model matched well those determined experimentally by isotopic transient analysis over the same catalysts.