cssi/SciSciGPT-SciSciNet huggingface dataset:
Increased forest ecosystem carbon and nitrogen storage from nitrogen rich bedrock

Bioavailable nitrogen commonly limits plant growth in natural ecosystems. In the absence of humans, this essential nutrient is thought to come mainly from the atmosphere through bacterial metabolism. Morford et al. present measurements of the nitrogen concentration and isotopic composition of rocks, soil and leaves to demonstrate that bedrock is a further, hitherto-overlooked source of bioavailable nitrogen to forests in the western United States. Furthermore, the forests growing above nitrogen-rich geology store appreciably more carbon than their impoverished counterparts. The authors suggest that this novel pathway might be a universal phenomenon. Nitrogen (N) limits the productivity of many ecosystems worldwide, thereby restricting the ability of terrestrial ecosystems to offset the effects of rising atmospheric CO2 emissions naturally1,2. Understanding input pathways of bioavailable N is therefore paramount for predicting carbon (C) storage on land, particularly in temperate and boreal forests3,4. Paradigms of nutrient cycling and limitation posit that new N enters terrestrial ecosystems solely from the atmosphere. Here we show that bedrock comprises a hitherto overlooked source of ecologically available N to forests. We report that the N content of soils and forest foliage on N-rich metasedimentary rocks (350–950 mg N kg−1) is elevated by more than 50% compared with similar temperate forest sites underlain by N-poor igneous parent material (30–70 mg N kg−1). Natural abundance N isotopes attribute this difference to rock-derived N: 15N/14N values for rock, soils and plants are indistinguishable in sites underlain by N-rich lithology, in marked contrast to sites on N-poor substrates. Furthermore, forests associated with N-rich parent material contain on average 42% more carbon in above-ground tree biomass and 60% more carbon in the upper 30 cm of the soil than similar sites underlain by N-poor rocks. Our results raise the possibility that bedrock N input may represent an important and overlooked component of ecosystem N and C cycling elsewhere.
OxyR contributes to the virulence of a Clonal Group A Escherichia coli strain (O17:K+:H18) in animal models of urinary tract infection, subcutaneous infection, and systemic sepsis.

The oxidative stress response regulator OxyR was assessed as both a urinary and extra-urinary virulence factor in Escherichia coli strain UCB34 (O17:K+:H18), a representative of the emergent Clonal Group A (CGA). Compared to UCB34, the isogenic oxyR mutant exhibited increased H2O2 sensitivity, indistinguishable in vitro growth, and attenuated virulence in rodent models of urinary tract, subcutaneous infection, and systemic sepsis. Complemented mutants showed virulence levels comparable to parent strains in all models. These findings uniquely fulfill molecular Koch's postulates for a putative virulence factor of CGA, provide experimental evidence of an extra-urinary virulence promoting trait in CGA, and document a role for OxyR in local and systemic extra-urinary E. coli infections.
CO oxidation on PtSn nanoparticle catalysts occurs at the interface of Pt and Sn oxide domains formed under reaction conditions

The barrier to CO oxidation on Pt catalysts is the strongly bound adsorbed CO, which inhibits O2 adsorption and hinders CO2 formation. Using reaction studies and in situ X-ray spectroscopy with colloidally prepared, monodisperse 2 nm Pt and PtSn nanoparticle catalysts, we show that the addition of Sn to Pt provides distinctly different reaction sites and a more efficient reaction mechanism for CO oxidation compared to pure Pt catalysts. To probe the influence of Sn, we intentionally poisoned the Pt component of the nanoparticle catalysts using a CO-rich atmosphere. With a reaction environment comprised of 100 Torr CO and 40 Torr O2 and a temperature range between 200 and 300 C, Pt and PtSn catalysts exhibited activation barriers for CO2 formation of 133 kJ/mol and 35 kJ/mol, respectively. While pure Sn is readily oxidized and is not active for CO oxidation, the addition of Sn to Pt provides an active site for O2 adsorption that is important when Pt is covered with CO. Sn oxide was identified as the active Sn species under reaction conditions by in situ ambient pressure X-ray photoelectron spectroscopy measurements. While chemical signatures of Pt and Sn indicated intermixed metallic components under reducing conditions, Pt and Sn were found to reversibly separate into isolated domains of Pt and oxidic Sn on the nanoparticle surface under reaction conditions of 100 mTorr CO and 40 mTorr O2 between temperatures of 200–275 C. Under these conditions, PtSn catalysts exhibited apparent reaction orders in O2 for CO2 production that were 0.5 and lower with increasing partial pressures. These reaction orders contrast the first-order dependence in O2 known for pure Pt. The differences in activation barriers, non-first-order dependence in O2, and the presence of a partially oxidized Sn indicate that the enhanced activity is due to a reaction mechanism that occurs at a Pt/Sn oxide interface present at the nanoparticle surface.
EVALUATION OF PULSE OXIMETER ACCURACY IN NEONATES

The Nellcor 100C pulse oximeter was studied with the following objectives: 1) to compare its reading with functional and fractional arterial oxygen saturation (SaO2), and 2) to establish 95% prediction intervals for individual pulse oximeter readings. Four arterial samples were obtained from each of 16 neonates less than 7 days of age, and compared to simultaneous pulse oximeter readings. Fetal hemoglobin was quantified on each infant (range 19-99%). Fractional SaO2 was measured on the IL 282 co-oximet.er and corrected for carboxyhemoglobin (Clin Chem 1983;29: 1555) .Fractional SaO2 was converted to functional SaO2: We found: 1) the pulse oximeter reading was closer to fractional SaO2 (p< 0.001). Agreement must be reached on whether to use fractional or functional SaO2 as the gold standard with which to compare pulse oximeter readings. 2) The width of the prediction interval was 12-13%. Thus with a reading of 90%, the SaO2 could be as low as 85%, or as high as 98%. The wide span of this prediction interval must be considered when using the pulse oximeter to control oxygen therapy in neonates.
Climate change and human security in Africa

Climate change poses a major threat to human security and poverty in Africa. In Africa, where livelihoods are mainly based on climate-dependent resources and environment, the effect of climate change will be disproportionate and severe. Moreover, Africa's capacity to adapt to and cope with the adverse effects of climate variability is generally weak. This article discusses how climate change affects human security in Africa. It also assesses the policy options available to policymakers in terms of mitigation and adaptation to climate change to reduce vulnerability and human insecurity in Africa.
Decreased plasma levels of lipoprotein(a) in patients with hypertriglyceridemia.

Lipoprotein(a) (Lp(a)) is an atherogenic lipoprotein which is similar in structure to, but metabolically distinct from, LDL. Factors modulating plasma Lp(a) concentrations are poorly understood. To investigate the possible interaction of Lp(a) with triglycerides, we determined the apo(a) phenotype, Lp(a) concentration, and distribution of Lp(a) in a group of patients with triglycerides > 400 mg/dl (n = 60) compared with a control group (n = 128). Lp(a) concentrations were significantly lower in hypertriglyceridemic patients (mean +/- S.E., 13 +/- 4 mg/dl; median, 6 mg/dl; 25/75 percentile, 2-13 mg/dl) as compared with the controls (mean, 22 +/- 2 mg/dl; median, 10 mg/dl; 25/75 percentile, 7-30 mg/dl). Plasma Lp(a) concentrations in the hypertriglyceridemic patients correlated negatively with triglyceride levels (r = -0.69, P = 0.03). The difference in Lp(a) levels between patients and controls was maintained when subjects were stratified by apo(a) phenotype and type of hyperlipidemia. After subdividing the hypertriglyceridemic patients into one group with apo(a) isoforms or = S3, we found that the differences in plasma Lp(a) concentrations between patients and controls were more pronounced in the group with the lower molecular weight apo(a) isoforms. These data indicate that hypertriglyceridemia is associated with lower plasma Lp(a) concentrations and suggest that increased levels of triglyceride-rich lipoproteins may influence the metabolism of Lp(a).
Lack of effectiveness of combined 5- fluorouracil and methyl-CCNU therapy in advanced colorectal cancer.

Fifty-two patients with advanced colorectal cancer were treated with a combination of 5-Fluorouracil (FU) plus methyl-1,3-cis (2-chlorethyl)-1-nitrosourea (MeCCNU). The treatment schedule program consisted of 5-FU, 300 mg/m2 i.v. bolus, daily for 5 days, repeated at 5-week cycles. MeCCNU was administered at a dose of 150 mg/m2 orally on day 1 of the initial 5-day course of FU and repeated at 10-week intervals. Eighty-four percent (44/52) of the patients with advanced measurable disease developed progressive disease by 4 months or one and a half cycles of therapy. Only two patients had definite partial regression of tumor over the period of observation. The median survival of all patients measured from the onset of treatment was 9 months and is comparable to literature reports of untreated advanced colorectal cancer. This therapeutic trial of combined FU and MeCCNU, employing a dose-schedule distinct from but comparable to previous studies has failed to confirm the substantial response rate reported by other investigators and reinforces the need for exploring new drugs and combinations of drugs in advanced colorectal cancer. The use of sequential plasma CEA determinations as a primary monitor of therapy is discussed in relationship to clinical trials and guidelines for determining significant quantitative changes in plasma CEA levels are recommended.
Mutations in a Conserved Motif Inhibit Single-stranded DNA Binding and Recombination Mediator Activities of Bacteriophage T4 UvsY Protein

The UvsY recombination mediator protein is critical for homologous recombination in bacteriophage T4. UvsY uses both protein-protein and protein-DNA interactions to mediate the assembly of the T4 UvsX recombinase onto single-stranded (ss) DNA, forming presynaptic filaments that initiate DNA strand exchange. UvsY helps UvsX compete with Gp32, the T4 ssDNA-binding protein, for binding sites on ssDNA, in part by destabilizing Gp32-ssDNA interactions, and in part by stabilizing UvsX-ssDNA interactions. The relative contributions of UvsY-ssDNA, UvsY-Gp32, UvsY-UvsX, and UvsY-UvsY interactions to these processes are only partially understood. The goal of this study was to isolate mutant forms of UvsY protein that are specifically defective in UvsY-ssDNA interactions, so that the contribution of this activity to recombination processes could be assessed independent of other factors. A conserved motif of UvsY found in other DNA-binding proteins was targeted for mutagenesis. Two missense mutants of UvsY were isolated in which ssDNA binding activity is compromised. These mutants retain self-association activity, and form stable associations with UvsX and Gp32 proteins in patterns similar to wild-type UvsY. Both mutants are partially, but not totally, defective in stimulating UvsX-catalyzed recombination functions including ssDNA-dependent ATP hydrolysis and DNA strand exchange. The data are consistent with a model in which UvsY plays bipartite roles in presynaptic filament assembly. Its protein-ssDNA interactions are suggested to moderate the destabilization of Gp32-ssDNA, whereas its protein-protein contacts induce a conformational change of the UvsX protein, giving UvsX a higher affinity for the ssDNA and allowing it to compete more effectively with Gp32 for binding sites.
Transcending life: The practice wisdom of nursing hospice experts

In philosophy and theology, to transcend is to go beyond the limits of lived human experience. Hospice workers accompany people who are traveling beyond the limits. "Whoever would be a companion to the dying, therefore, must enter into their darkness, go with them at least part way along their lonely and frightening road." This paper explores the requisite hospice practice competencies of caring spiritually and guiding letting go, as identified in a qualitative analysis of the practice stories of 32 hospice nurse experts working with people nearing death. Spirituality has been described as the essence of personhood, the longing for meaning in existence, experience of God, experience of ultimate values, and trust in the transcendent. Its ultimate end is union or connection with a reality more enduring than the individual self. In contrast, spiritual distress is manifested as alienation and disconnection. The reality of the dying process involves a progressive series of disconnections from life, which requires the process of letting go. Thus, transcending life involves both the need to detach and separate from life as it has been lived. One home visiting hospice nurse has described dying as a spiritual process of both reflecting and detaching. Nagai-Jacobsen and Burkhardt identify three goals of caring spiritually: Fostering personal integrity; Promoting interpersonal connection; Supporting personal search for meaning. O'Connor describes hospice spiritual care promoted through the practice of presence, compassion, hopefulness, and the affirmation of life as fruitful. Stiles has completed the only published qualitative description of hospice nursing as spiritual care.(ABSTRACT TRUNCATED AT 250 WORDS)
Petrogenesis of the nakhlite meteorites - Evidence from cumulate mineral zoning

Attention is given to a simple igneous petrogenesis for the meteorite Nakhla, which was previously called into question because Mg/Fe ratios in olivine indicate substantial disequilibrium between the predominant cumulus minerals (olivine and augite). Comparative analyses of simulated diffusive zoning and the observed cumulus mineral zoning for all three nakhlites (Nakhla, Governador Valadares, and Lafayette) show that their current compositions do not necessarily reflect parental magma compositions. Diffusion has altered primary cumulus compositions to varying degrees, Nakhla being the least affected, and Lafayette being almost completely reequilibrated. Since mineral zoning in each meteorite is strongly concentric around mesostasis areas, it is inferred that reaction with intercumulus liquid has controlled the observed zoning. It is argued that the nakhlites appear to be a series of relatively simple cumulate rocks which have undergone various amounts of late-magmatic and subsolidus diffusion, possibly reflecting their relative positions in a cooling cumulate pile.
Software population pyramids: the current and the future of OSS development communities

Context: Since human power is an essential resource, the number of contributors in a software development community is one of the health indicators of an open source software (OSS) project. For maintaining and increasing the populations in software development communities, both attracting new contributors and retaining existing contributors are important. Goal: Our goal is understanding the current status of projects' population, especially the different experienced contributors' composition of the projects. Method: We propose software population pyramids, a graphical illustration of the distribution of various experience groups in a software development community. Results: From the study with OSS projects in GitHub, we found that the shapes of software population pyramids varies depending on the current status of OSS development communities. Conclusions: This paper present a software population pyramid of the distribution of various experience groups in a software community population. Our results can be considered as predictors of the near future of a project.
KINETICS OF OXYGEN UPTAKE IN LIQUID FOODS

An important consideration in the investigation of liquid food quality degradation by oxidative reactions is the kinetics of oxygen uptake. The purpose of this research was to investigate oxygen uptake rates in a liquid food during storage. A commercially prepared infant formula was used as the model system. The influence of three variables (light intensity, storage temperature and initial concentration of dissolved oxygen) on the rate of oxygen uptake was determined. Results of the study indicated that the oxygen uptake in liquid foods follows fist order rate kinetics during the first 24 hr of storage. In the range of 0–4300 lux, it was found that the rate of oxygen uptake increases linearly with increasing light intensity. The rate of oxygen uptake at three different levels of initial dissolved oxygen from 1 mg/liter to nearly saturation showed that the rate of oxygen uptake increases linearly with increasing initial dissolved oxygen concentration. The influence of temperature on rate of oxygen uptake indicated that the Arrhenius equation could be used to describe the relationship.
Characterization of a boron neutron capture therapy beam line at the University of Missouri Research Reactor

A new research effort aimed at increasing the catalog of boron delivery agents for boron neutron capture therapy (BNCT) has been undertaken by the International Institute of Nano and Molecular Medicine (IINMM) at the University of Missouri. The MU Research Reactor (MURR) and Idaho National Laboratory (INL) have constructed a facility for small animal BNCT experiments. The facility incorporates silicon and bismuth single crystal filters to produce a thermal neutron beam. The thermal beam has a measured thermal flux of 8.8 × 108 n cm−2 s−1 and a gold cadmium ratio of 130. The neutron and photon dose rates were measured using paired ion chambers.
Fluorescein-hemoglobin as a substrate for cathepsin D and other proteases

Abstract A sensitive fluorometric assay for cathepsin D and other proteases is described. The method is based upon a hemoglobin substrate modified by being linked with fluorescein isothiocyanate. Trichloroacetic acid soluble hydrolysis products are diluted with 0.1 N NaOH and the fluorescence is read at 515 nm with excitation at 490 nm. The method satisfies the conditions for linearity of reaction velocity with incubation time and for proportionality with enzyme concentration. The main advantages of the assay are high sensitivity and short time requirement. Specific and general applications of the method are described.
Indirect computed tomography venography of the lower extremities using single-source dual-energy computed tomography: Advantage of low-kiloelectron volt monochromatic images

Abstract Purpose To study the performance of dual-energy indirect computed tomography (CT) venography from single-source dual-energy CT in the assessment of lower extremity deep venous thrombosis (DVT). Materials and Methods In a retrospective study, 110 patients suspected to have pulmonary embolism (PE) underwent dual-energy CT venography on a single-source dual-energy CT scanner as a part of CT pulmonary angiography protocol at 3 minutes after injection of contrast material. Two radiologists evaluated 50-kiloelectron volt (keV) and 70-keV monochromatic images reconstructed from a dual-energy CT scan for image quality, image noise, venous contrast, and confidence level in interpretation for DVT using a scale of 1–5. In addition, a combined 50-keV and 70-keV data set was assessed for confidence level in image interpretation. Attenuation, contrast-to-noise ratio (CNR), and objective noise were measured in bilateral common femoral and popliteal veins. Data were analyzed using Student t test and Wilcoxon rank sum test. Radiation dose was measured for dual-energy CT venography protocol. Results A diagnosis of DVT was made in 8 of 110 patients (7.27%). The subjective image quality was comparable between 50-keV and 70-keV images (4.3 vs 4.5; P > .05). The subjective venous contrast opacification (4.7 vs 3.5; P = .0036) and confidence (4.8 vs 3.9; P = .0028) in image interpretation were superior at 50 keV. Confidence level for interpretation on combined 50-keV and 70-keV series (score 4.7) was similar to that for 50-keV series (score 4.8). Compared with 70-keV data, 50-keV data yielded 90% increase in intravascular CT attenuation (207.4 Hounsfield units [HU] ± 39.0 vs 106.8 HU ±7.6; P P = .0001) of the deep veins. However, objective noise at 50 keV was higher (14.8 HU vs 6.5 HU; P = .0031). Because of inadequate contrast opacification, 6% of CT venography studies were deemed suboptimal for rendering a diagnostic interpretation on 70-keV images, but these images were considered acceptable at 50 keV. The mean effective radiation dose for the dual-energy CT venography examination was 4.2 mSv. Conclusions Optimal image quality with substantially higher venous attenuation is provided by 50-keV monochromatic images from dual-energy CT venography acquisition compared with 70-keV images. The 50-keV monochromatic images increase the confidence in the image interpretation of DVT and decrease the number of indeterminate studies.
DNA Transposition by the RAG1 and RAG2 Proteins: A Possible Source of Oncogenic Translocations

The RAG1 and RAG2 proteins are known to initiate V(D)J recombination by making a double-strand break between the recombination signal sequence (RSS) and the neighboring coding DNA. We show that these proteins can also drive the coupled insertion of cleaved recombination signals into new DNA sites in a transpositional reaction. This RAG-mediated DNA transfer provides strong evidence for the evolution of the V(D)J recombination system from an ancient mobile DNA element and suggests that repeated transposition may have promoted the expansion of the antigen receptor loci. The inappropriate diversion of V(D)J rearrangement to a transpositional pathway may also help to explain certain types of DNA translocation associated with lymphatic tumors.
Genetic modification and recombination of salivary gland organ cultures.

Branching morphogenesis occurs during the development of many organs, and the embryonic mouse submandibular gland (SMG) is a classical model for the study of branching morphogenesis. In the developing SMG, this process involves iterative steps of epithelial bud and duct formation, to ultimately give rise to a complex branched network of acini and ducts, which serve to produce and modify/transport the saliva, respectively, into the oral cavity1-3. The epithelial-associated basement membrane and aspects of the mesenchymal compartment, including the mesenchyme cells, growth factors and the extracellular matrix, produced by these cells, are critical to the branching mechanism, although how the cellular and molecular events are coordinated remains poorly understood 4. The study of the molecular mechanisms driving epithelial morphogenesis advances our understanding of developmental mechanisms and provides insight into possible regenerative medicine approaches. Such studies have been hampered due to the lack of effective methods for genetic manipulation of the salivary epithelium. Currently, adenoviral transduction represents the most effective method for targeting epithelial cells in adult glands in vivo5. However, in embryonic explants, dense mesenchyme and the basement membrane surrounding the epithelial cells impedes viral access to the epithelial cells. If the mesenchyme is removed, the epithelium can be transfected using adenoviruses, and epithelial rudiments can resume branching morphogenesis in the presence of Matrigel or laminin-1116,7. Mesenchyme-free epithelial rudiment growth also requires additional supplementation with soluble growth factors and does not fully recapitulate branching morphogenesis as it occurs in intact glands8. Here we describe a technique which facilitates adenoviral transduction of epithelial cells and culture of the transfected epithelium with associated mesenchyme. Following microdissection of the embryonic SMGs, removal of the mesenchyme, and viral infection of the epithelium with a GFP-containing adenovirus, we show that the epithelium spontaneously recombines with uninfected mesenchyme, recapitulating intact SMG glandular structure and branching morphogenesis. The genetically modified epithelial cell population can be easily monitored using standard fluorescence microscopy methods, if fluorescently-tagged adenoviral constructs are used. The tissue recombination method described here is currently the most effective and accessible method for transfection of epithelial cells with a wild-type or mutant vector within a complex 3D tissue construct that does not require generation of transgenic animals.
Strong segregation gettering of transition metals by implantation-formed cavities and boron-silicide precipitates in silicon

We have mechanistically and quantitatively characterized the binding of transition-metal impurities in Si to cavities formed by He implantation and to B-Si precipitates resulting from B implantation. Both sinks are inferred to act by the segregation of metal atoms to pre-existing low-energy sites, namely surface chemisorption sites in the case of cavities and bulk solution sites in the case of the B-Si phase. These gettering processes exhibit large binding energies, and they are predicted to remain active for arbitrarily small initial impurity concentrations as a result of the segregation mechanisms. Both appear promising for gettering in Si devices.
The Papain-Like Protease of Severe Acute Respiratory Syndrome Coronavirus Has Deubiquitinating Activity

Replication of the genomic RNA of severe acute respiratory syndrome coronavirus (SARS-CoV) is mediated by replicase polyproteins that are processed by two viral proteases, papain-like protease (PLpro) and 3C-like protease (3CLpro). Previously, we showed that SARS-CoV PLpro processes the replicase polyprotein at three conserved cleavage sites. Here, we report the identification and characterization of a 316-amino-acid catalytic core domain of PLpro that can efficiently cleave replicase substrates in trans-cleavage assays and peptide substrates in fluorescent resonance energy transfer-based protease assays. We performed bioinformatics analysis on 16 papain-like protease domains from nine different coronaviruses and identified a putative catalytic triad (Cys1651-His1812-Asp1826) and zinc-binding site. Mutagenesis studies revealed that Asp1826 and the four cysteine residues involved in zinc binding are essential for SARS-CoV PLpro activity. Molecular modeling of SARS-CoV PLpro suggested that this catalytic core may also have deubiquitinating activity. We tested this hypothesis by measuring the deubiquitinating activity of PLpro by two independent assays. SARS CoV-PLpro hydrolyzed both diubiquitin and ubiquitin-7-amino-4-methylcoumarin (AMC) substrates, and hydrolysis of ubiquitin-AMC is approximately 180-fold more efficient than hydrolysis of a peptide substrate that mimics the PLpro replicase recognition sequence. To investigate the critical determinants recognized by PLpro, we performed site-directed mutagenesis on the P6 to P2' residues at each of the three PLpro cleavage sites. We found that PLpro recognizes the consensus cleavage sequence LXGG, which is also the consensus sequence recognized by cellular deubiquitinating enzymes. This similarity in the substrate recognition sites should be considered during the development of SARS-CoV PLpro inhibitors.
Infrared radiative heat transfer in nongray gases

Abstract The object of this investigation is to study various approximate methods of analyzing infrared radiative heat transfer in nongray nonisothermal gases. For this purpose, a very simple physical system was chosen consisting of a gas bounded by two infinite parallel black plates having the same uniform temperature. There is a uniform heat source (or sink) within the gas. Furthermore, attention is restricted to gases having a single fundamental vibration-rotation band; that is, diatomic gases. It is found that for intermediate optical thicknesses, the line structure of the vibration-rotation band can have a significant effect upon the temperature distribution within the gas. Predictions based on the gray gas assumption are shown to be greatly in error. It is further illustrated that one cannot apply the optically thick limit to an entire vibration-rotation band, since there will always be an optically non-thick region in the band wings, and such regions will contribute significantly to the radiative transfer process.
Primary structure of the essential thiol peptide from the lactate dehydrogenase C subunit

Abstract Lactate dehydrogenase isozymes are inhibited when mercurial reagents are bound to cysteine-165 although no functional role is ascribed to this residue. Identical tryptic peptides containing this cysteine have been isolated from many LDH isozymes, including both A and B subunits. This report identifies an identical peptide from a third subunit type, C, of mouse. The rigorous conservation of this sequence implies an important functional role for this region of the molecule.
The effect of compactness on the carbothermal conversion of interpenetrating metal oxide/resorcinol-formaldehyde nanoparticle networks to porous metals and carbides

This study establishes that the necessary and sufficient condition for efficient reaction between nanoparticles includes both high surface-to-volume ratios and high compactness. For this, a wide range of interpenetrating networks of resorcinol-formaldehyde (RF) and metal oxide (MOx, M: Fe, Co, Ni, Sn, Cu, Cr, Ti, Hf, Y, Dy) nanoparticles were synthesized via a simple one-pot process using the acidity of gelling solutions of hydrated metal ions to catalyze gelation of RF. The compactness of the nanoparticles in the dry composites is controlled by the drying method: supercritical fluid (SCF) CO2 drying affords aerogels with open skeletal frameworks, while drying under ambient pressure yields much more compact xerogels. A second independent method to impart compactness is by crosslinking the framework nanoparticles with a conformal polyurea (PUA) coating followed by drying with SCF CO2: although those materials (X-aerogels) have an open aerogel-like structure, upon heating in the 200 °C range, the conformal PUA coating melts and causes local structural collapse of the underlying framework creating macropores defined by xerogel-like walls. Depending on the chemical identity of the metal ion, pyrolysis at higher temperatures sets off carbothermal processes yielding pure metal monolithic nanostructures (up to 800 °C; cases of M; Fe, Co, Ni, Sn, Cu) or carbides (up to 1400 °C; cases of M: Cr, Ti, Hf). Irrespective of the specific chemical processes responsible for those transformations, the rate determining factor is the innate compactness of the xerogels, or the induced skeletal compactness in X-aerogels: both kind of materials react at as much as 400 °C lower temperatures than their corresponding native aerogels. By comparison, bulk (micron size) mixtures of the corresponding oxides and carbon black remained practically unreacted in the entire temperature range used for the nanoparticle networks. In addition to the significance of the RF-MOx interpenetrating networks in the design of new materials (mesoporous and macroporous monolithic metals and carbides), the effect of compactness on the activation of the carbothermal processes has important implications for process-design engineering.
Programmable multilayer optical neural networks with asymmetric interconnection weights

A hybrid optical-electronic architecture is described which uses gratings stored in a photorefractive crystal to interconnect neurons using coherent light beams. Neurons are represented by pixels on two liquid crystal light valves. Threshold functions are implemented electronically using lookup tables. Area transformation of two neuron planes are used to implement arbitrary multilayer neural networks with asymmetric interconnection weights using a single hologram to store the interconnection pattern. Some factors limiting storage capacity and processing speed are discussed. >
A Matchmaking Methodology for Supply Chain Deployment in Distributed Manufacturing Environments

In modern manufacturing era, supply chains are increasingly becoming global and agile. To build agile global supply chains, companies first need to have access to a large supply base and secondly need an efficient mechanism for cost-effective and rapid location, evaluation, and selection of suppliers. This work introduces a matchmaking algorithm for connecting buyers and sellers of manufacturing services based on their semantic similarities in terms of manufacturing capabilities. The proposed matchmaking algorithm operates over Manufacturing Service Description Language (MSDL), an ontology for formal representation of manufacturing services. Since MSDL descriptions can be represented as directed labeled trees, a tree matching approach is implemented in this work.
Health status and the end-of-life stage

Abstract Although numerous studies highlight the social, psychological, and physiological significance of life stages based on specific ages, little scholarly attention has been devoted to identifying factors that distinguish the stage prior to death. Instead of conceptualizing the life course as stages delineated by specific ages, our study explores the changes in self-rated health status and functional health limitations that occur when older adults pass from a vital stage of life into the end-of-life stage. Using data from the Longitudinal Study on Aging, we compare the health status of those at varying points near the end-of-life (died within 1–6 years from the initial interview) to vital survivors (survived beyond 6 years). Controlling for age, sex, race, education, and a host of diagnosed diseases and serious health conditions, those in the end-of-life stage have more lower and upper body limitations, greater difficulty with activities of daily living, and worse overall self-rated health than vital survivors. We conclude that the end-of-life stage should be considered a unique period in the life course that is irreducible to age.
The insight-value-perception (iVP) model for user-centered design

Abstract Through an inductive, multi-case analysis of eight medical device firms, this paper maps user-centered design and development practices to product performance outcomes. First, the data highlight that designing products under variable use conditions enabled firms to optimize products for widespread use and to increase the predictability of product outcomes. Second, the study shows that product adoption relied on maximizing benefits for multiple product stakeholders with often-conflicting needs, while minimizing required changes in end user behavior. Third, the paper highlights that managing perceptions toward product use through performance data positively influenced product adoption among the cases studied to a greater degree than did market demand or regulatory clearance. Fourth, rival explanations for outcomes involving limited user involvement, indicate that competitive advantages were achieved through maintaining dominant financial and intellectual property positions. From these findings, the insight-value-perception (iVP) model for user-centered design was constructed. This model links design and development practices to outcomes, from a combination of consumer-oriented, technical, and financial perspectives. Although rooted in the experiences of device developers within early stage medical device companies, the iVP Model may be used as a theoretical framework to examine a range of complex systems involving an embedded network of product users and stakeholders.
Processing of analytical signals using Matlab

Abstract Matlab is a software package for matrix manipulation that can also be used as a high-level programming language. In this article the application of Matlab in the implementation of several signal processing algorithms used in analytical chemistry is discussed. Some of the popular algorithms are explained and their software implementation in Matlab are presented. A brief tutorial on Matlab is also presented with some coding examples. Mitra, S. and Bose, T., 1994. Processing of analytical signals using Matlab. Chemometrics and Intelligent Laboratory Systems , 22: 3–16.
Wettability of cotton modified by admicellar polymerization

The wettability of yarns from plain cotton fabric and from polystrene-coated fabric modified by admicellar polymerization was examined by transient force measurements with a microbalance. Analysis of the observed time scales and forces suggests that water transport in cotton yarn proceeds by an initial rapid, capillary-driven axial flow over the exterior, followed by a radial flow between fibers, and is completed by a slow diffusion of water into the individual fibers. Both the initial and final forces indicated a significant reduction in the affinity of the modified fabric for water. Admicellar polymerization after optimization yielded coated cotton yarn that absorbed only 3% of the water retained by the unmodified yarn.
Laser Weather Identifier: Present and Future

Abstract Prototype Laser Weather Identifier (LWI) systems designed to detect fog, rain and snow were tested for several months at Stapleton International Airport in Denver, and at the AFGL Weather Test Facility at Otis Air Force Base, Massachusetts. We present a detailed analysis of the performance of these systems, compared with human weather observations and tipping-bucket raingages, and suggest modifications for future operational instruments.
Strong realcompactness and weakly measurable cardinals

Denote βX − X by X∗. Define properties P0 and P1 of a space X by Pi (i<2): if D ⊆ X∗ is countable and relatively discrete and if D is compact, then - if i = 0: D ≠ αD, the smallest (=one-point) compactification of D, - if i = 1: D = βD, the biggest (=Cech-Stone) compactification of D. (Note: X has P0 iff X∗ has no nontrivial convergent sequences.) Realcompact spaces are known to have P0, and a dense-in-itself metrizable space with P0 is realcompact. There is a separable first countable locally compact realcompact normal space without P1. The question of whether there is a realcompact metrizable space without P1 leads to a new small large cardinal. There is one iff there is a weakly measurable cardinal that is not measurable; a cardinal κ is called weakly measurable if there is a countable set F of free ultrafilters on κ such that the filter ∩ F is κ-complete. Let κ be the first weakly measurable cardinal that is not measurable (if there is one). We show that κ < c and κ ≠ cf c and that Con(ZFC + ∃ measurable)⇒Con(ZFC + κ exists).
A reduced complexity DS-CDMA system for personal communication networks

Most of the analyses of direct sequence-code division multiple access (DS-CDMA) protocols for centralized packet radio networks are based on the assumption that each system user has a unique spread spectrum code and there is a receiver for each user at the central station. For a system with a very large number of users, this implies a very complex central station. The authors develop a more efficient DS-CDMA protocol for centralized packet radio networks, which reduces the central station complexity in terms of the required number of receivers, while maintaining the channel throughput at an acceptable level. To reduce the central station complexity, the authors group all system users into cells and assume that all users in a given cell use the same spread spectrum code. It is found that the central station complexity reduction can be obtained at the price of throughput reduction. However, with an appropriate choice of system parameters, the throughput reduction can be made insignificant compared to the reduction achieved with the required number of receivers. >
PERFORMANCE CHARACTERISTICS OF A DIGITAL FLUOROGRAPHIC SYSTEM.

Abstract Several technical characteristics of digital fluorography are discussed. A derivation is made for the noise levels in the acquisition of digital fluorographic video images. The importance of high video signal-to-noise ratio is demonstrated and discussed. A noise analysis is made for reprocessing amplified difference images from analog video disk. It is shown that under the most stringent circumstances a disk with a signal-to- noise ratio of 200:1 increases the rms noise by at most 7%. Potential artifacts associated with the measurement of iodine sensitivity for digital radio-graphic systems are discussed. A phantom is presented which eliminates such artifacts. Experimental digital fluorographic phantom images are shown.The effects of noise in the acquisition of digital fluorographic imagesIn the conversion of the x-ray fluence detected at the input phosphor of an image intensifier to a video signal, virtually all stages are statistical ones. Thus, the original uncertainty in the detection of a finite number of x-rays is potentially increased at each step. A detailed discussion of this conversion process is given by Roehrig et al.^ In addition to the x-ray detection statistics the other major noise source is the contribution from the video electronics. In this section we study how these noise components enter into a logarithmically amplified video image.A derivation of the noise levels of x-ray statistical and electrical components as a function of signal level has been given in earlier works^/3f but, because of its importance in digital fluorography, it is repeated here. The result will be used in the next section in the derivation of the noise levels that result when images stored on an analog video disk are reprocessed. We make the following definitions:V = video signal voltage when the maximum useable signal max current is read from the camera target.aE = the rms noise voltage in the video signal due to non x-ray statistical sources.SNR = V max /a hi = video signal-to-noise ratio, N = the detected x-rays per pixel corresponding to V , 0 the brightest point in the video image. maxN = detected x-rays per pixel corresponding to darker portions of the video image.= N exp(-yx) where x is incremental object thickness.a = a to gain, V such as video camera aperture, which maps N° maxV can be measured by determining the region over which the camera has a smooth output asPa function of input light level. V is the largest output level in this region just below saturation. Similarly a canxbe measured as the rms signal variation read from the camera with no light input: Thus, the SNR can be determined experimentally. We are making the approximation that a measured for darkest signal is same for all signal levels. Although in fact a increases slightly with signal this does not alter our conclusions as will be shown?The video signal read from the camera is given by:V = otN + m (1) where m represents the video noise.
Effects of genotype on differential behavioral responsiveness to progesterone and 5alpha-dihdroprogesterone in mice.

Thirty female CD-1 mice, 30 female Swiss-Webster mice, 45 hybrid female mice of the strain SWCD1F1, and 45 hybrid female mice of the strain CD1SWF1 were ovariectomized and administered estradiol benzoate once weekly for 6 weeks. Estrogen injections were followed 2 days later by injections of progesterone, dihydroprogesterone (DHP), or oil and the animals were tested for receptivity 7 hr later. Over the six tests, there was a progressive increase in the frequency of lordosis responses in all strains following progesterone treatment. However, lordosis scores varied widely across animals within strains. Following DHP treatment, lordosis frequency was not increased in the Swiss-Webster strain. Females in the other strains did show a progressive increase in lordosis frequency over weeks. The data indicate that the hybrid strains develop the potential to respond to DHP and thus behave like the CD-1 strain, suggesting that sensitivity to DHP is a dominant trait.
Measurement of the Linewidth Enhancement Factor of a 1550-nm Injection-Locked Quantum Dash Laser

Injection-locking in quantum dash lasers is studied for the first time. A measurement of the linewidth enhancement factor from 1.2-8.6 is obtained by comparing the positive and negative detuning ranges of the stable locking regime.
Distribution of transcripts of thetub B1 β-tubulin gene in developing soybean (Glycine max [L.] Merr.) seedling organs

A previously cloned and sequenced soybean (Glycine max [L.] Merr.) β-tubulin gene, designatedtub B1, encodes a rather divergent β-tubulin protein and appears to be transcribed in a developmentally regulated manner. The steady state level oftub B1 gene transcripts in seedling tissues and organs was examined using a sensitive RNase protection assay and atub B1-gene-specific probe. A soybean ubiquitin gene probe was used as a control to insure that equivalent amounts of RNA were assayed from each sample. Consistent with a previous report of ours, we observed high levels oftub B1 gene transcripts only in the hypocotyls of etiolated seedlings. Illumination of the etiolated seedlings at any time between day three and six halted further hypocotyl elongation and reduced thetub B1 gene transcripts levels to near the detection limit of the RNase protection assay. Here we show further thattub B1 transcripts are confined to the apical-most region of the etiolated hypocotyl, including the hypocotyl hook and the subjacent region of cell elongation, and are absent in the lower half of the hypocotyl throughout its development. However, transcripts of thetub B1 gene also were detected in the cotyledons at low levels. Transcript levels did not change significantly during cotyledon development and the transcript levels were not significantly affected by environmental conditions. Illumination of the seedlings did not decreasetub B1 transcript levels in cotyledons, as it did in the hypocotyls, and may even have increased these slightly, as compared to transcript levels present in the cotyledons of etiolated seedlings. Low levels oftub B1 gene transcripts also were detected in the terminal 2 cm of the root, but the appearance oftub B1 gene transcripts in these tissues was transitory. Transcripts were most abundant in the root within the first few days of germination. They declined subsequently and were not detectable after the sixth day of germination. Transcripts of an additional five β-tubulin genes were detected in etiolated hypocotyls using a PCR technique. Transcripts of another two β-tubulin genes were found in light-grown hypocotyls, but not in etiolated hypocotyls. Thus, thetub B1 gene exhibits a complex, and apparently unique, pattern of expression. It exhibits apparently constitutive expression in cotyledons, temporally regulated expression in the root, and strong, organspecific expression in the hypocotyl, but only in dark-grown seedlings, and this hypocotyl expression is down-regulated dramatically by light.