cssi/SciSciGPT-SciSciNet huggingface dataset:
STRUCTURE STUDIES OF ALUMINUM BASED QUASICRYSTALS

Etude par diffraction de rayons X et microscopie electronique a transmission de AlMn et AlMnSi quasi cristallins
SU‐GG‐T‐370: Optical Fiber Based Ionizing Radiation Microdetector

Purpose: Develop an optical fiber based isotropic detector for ionizing radiationdose in water‐equivalent materials that could be used for a variety of measurements in situations where isotropy and spatial resolution are of major concern (e.g. for IMRT, IGRT, and brachytherapy QA in complex non‐idealized geometry settings, where currently available diode‐type detectors display relatively large un‐isotropy). Method and Materials: Commercially available plastic scintillators, optical fibers, a QE65000 Ocean Optics spectrometer, and a laptop computer were used to measure the response of “in house” built milimetric detectors for several setups and known calibrated ionizing radiation beams (from a Varian 21EX linear accelerator). Results: A proportional response was observed for the known dose at different depths in a water‐equivalent phantom for 6 MV and 18 MV photon beams and electron beams between 6 MeV and 20 MeV in a relatively wide window of the measured spectra, after background and stray light corrections were applied. Conclusion: A relatively simple, robust, and inexpensive isotropic detector based device can be developed by replacing the spectrometer with a set of inexpensive light detectors with an efficient response at the desired wavelength window.
Potent mutagenic impurities in a commercial sample of 3-nitro-9-fluorenone.

Abstract A commercial sample of 3-nitro-9-fluorenone was a pontent mutagen in the Ames Salmonella assay, producing 1000 TA98 net revertants per plate at 0.76 μg/plate without the presence of liver homogenates (−S9). After purification by high-pressur liquid chromatography (HPLC), 3-nitro-9-fluorenone was found to be at least 6 times less active than the parent sample. The commercial sample was fractionated by HPLC and the mutagenic impurity peaks collected and subjected to high-resolution mass spectrometry (HRMS). The mass spectra of 2 potent mutagenic fractions showed the principal molecular species to be a dinitrofluorenone and an acetamidomononitrofluorenone. Samples of synthetic 2,7-dinitro-9-fluorenone and 2-acetamido-3-nitro-9-fluorenone had mutagenic activities, HPLC retention times, and mass spectra characteristics similar to the mutagenic impurity fractions collected from the commercial sample.
Cysteine transfer RNA of Escherichia coli: nucleotide sequence and unusual metabolic properties of the 3' C-C-A terminus.

Transfer RNA nucleotidyltransferase is required for the normal growth of Escherichia coli and for biosynthesis of some bacteriophage tRNAs. In order to investigate the involvement of this enzyme in the biosynthesis of E. coli tRNA we have studied the synthesis of these molecules in wild-type ( cca + ) and tRNA nucleotidyltransferase-deficient ( cca ) strains. We found that a small subset of tRNA species lack a complete C-C-A terminus in the cca strain. Within this subset of tRNAs, tRNA Cys was the most severely affected; nucleotide sequence analysis showed that 79% of tRNA Cys molecules lacked one or more of the 3′-terminal C-C-A residues. However, in this same cca strain, the tRNA Cys synthesized in the presence of chloramphenicol, an antibiotic which inhibits turnover of the terminal AMP residue of tRNAs, possessed a complete C-C-A terminus. These results indicate that tRNA nucleotidyltransferase is not required for the biosynthesis of tRNA Cys . We infer from these findings that the 3′ C-C-A sequence of tRNA Cys arises during transcription, and that the high proportion of defective tRNA Cys molecules found in cca cells results from unusually high turnover at the 3′ terminus of this tRNA. This conclusion must be stated with some reservation, for it is based on studies using a mutant strain which contains 2% residual tRNA nucleotidyltransferase activity. Regardless of its mode of biosynthesis, however, tRNA Cys does possess an unusual metabolic feature in that it is subject to rapid end-turnover. We have not determined why tRNA Cys exhibits such unusual behavior.
Differences in Freeze Tolerance of Zoysiagrasses: I. Role of Proteins

Genotypic variation in winter injury exists among zoysiagrasses (Zoysia spp.), but the physiological basis for these differences is not understood. Our objective was to determine the relationships between protein accumulation, polypeptide compo sition, and freeze tolerance of zoysiagrass. Thirteen genotypes of zoysiagrass with contrasting cold hardiness were identifi ed. Cold acclimation was induced with 4 wk of 8/2°C day/night cycles and a 10-h photoperiod of 300 μmol m −2 s −1 . Rhizomes and stolons of zoysiagrass were harvested from nonacclimated and cold-acclimated plants and used for protein analysis. Protein composition was analyzed using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting with an antidehydrin polyclonal antibody. Buffer-soluble protein concentrations were higher among coldacclimated (7.3 g kg −1 dry wt.) than nonacclimated (5.1 g kg −1 dry wt.) plants. The SDS-PAGE analysis indicated few differences in polypeptide composition among genotypes irrespective of cold acclimation. Immunoblotting indicated that dehydrin polypeptides (23 and 25 kDa) increased during cold acclimation. Abundance of the 23kDa dehydrin polypeptide was positively associated (r 2 = 0.41) with genetic variation in freezing tolerance. Our results suggest that dehydrins are associated with zoysiagrass cold acclimation, but that only the 23-kDa dehydrin plays a role in improving freeze tolerance.
Out of sight, out of compliance: US detained girls’ health justice

Due to an overreliance on arrests in the late 1990s, the incarceration of young women in the United States increased dramatically. On any given day in 2010, over 9000 girls were held in residential placement. Largely hidden from public view, little is known about the health requirements of female adolescent offenders in US secure custody. Less is known about how those needs are met while in detention. Curiously, while most theories regarding female juvenile delinquency draw upon non-criminogenic health-related factors – sexual abuse, family violence, and low self-esteem – their specific legal troubles are rarely, if ever, framed in public health terms. Drawing on original interviews with 100 court-involved girls, detainees’ perceptions of their medical, psychological, sexual, and social health concerns are highlighted. The data link court-involved girls’ prior health issues to their coming to the attention of juvenile authorities as well as demonstrating possible non-compliance with domestic and internati...
Steady finite motions of a conducting liquid

In certain cases of steady motion of a conducting fluid in a magnetic field, the primitive equations may be integrated once, yielding a second-order partial differential equation in the stream function. This equation is highly non-linear in general, but for certain choices of basic flow and magnetic fields it is tractable. Several arbitrary functions of integration have to be evaluated to make the analysis useful. This may be done in a region that remains undisturbed. A short discussion is given to suggest a procedure for deciding in a spectal case whether this undisturbed region is "upstream" or "downstream". (auth)
AN ENUMERATION METHOD FOR THE MINIMAL PATHS OF NETWORK SYSTEMS

This paper presents a technique for the enumeration of minimal paths of two-terminal networks. The method is developed based on the multiway tree structure that has been used widely for sorting and searching. The new technique does not require any matrix multiplication; it only requires a connection matrix. Furthermore, this simple method has capability of evaluating the reliability of a network after a topological modification, without going through the entire evaluation process. The method is compared with the existing algorithms, and the application simplicity of this method is demonstrated through examples.
The Invisible Y: A Case for Spelling in Pronunciation Learning

What can a teacher say to help the student whose rendering of community sounds like come-moon-ity and whose ridiculous rhymes with tickle us? One possibility is, “Go to a dictionary and look up the pronunciation of these words.” Another, more helpful possibility is, “Let me show you whereto use the Invisible Y in English,” The Invisible Y is the unwritten /y/ that is required in continue, omitted in construe, optional in continuity, and in issue, combines to make /s/ in American English speech but remains /sy/ in some British English speech. Its apparent erratic behavior is a point of frustration for ESL learners, for whom there is virtually no guidance. This article 1) shows that the learner's mistakes in this area ordinarily arise, not from a lack of articulatory skill, but from a lack of information about the system; 2) presents the simple rules governing the use of the Invisible Y, rules accessible to learners through standard orthography; and 3) discusses how standard orthography can be used as a pronunciation resource for learners.
High glucose alters Cx43 expression and gap junction intercellular communication in retinal Müller cells: promotes Müller cell and pericyte apoptosis.

Purpose To investigate whether high glucose (HG) alters connexin 43 (Cx43) expression and gap junction intercellular communication (GJIC) activity in retinal Muller cells, and promotes Muller cell and pericyte loss. Methods Retinal Muller cells (rMC-1) and cocultures of rMC-1 and retinal pericytes were grown in normal (N) or HG (30 mM glucose) medium. Additionally, rMC-1 transfected with Cx43 small interfering RNA (siRNA) were grown as cocultures with pericytes, and rMC-1 transfected with Cx43 plasmid were grown in HG. Expression of Cx43 was determined by Western blotting and immunostaining and GJIC was assessed by scrape-loading dye transfer (SLDT) technique. Apoptosis was analyzed by TUNEL or differential staining assay, and Akt activation by assessing Akt phosphorylation. Results In monocultures of rMC-1 and cocultures of rMC-1 and pericytes, Cx43 protein level, number of Cx43 plaques, GJIC, and Akt phosphorylation were significantly reduced in HG medium. Number of TUNEL-positive cells was also significantly increased in rMC-1 monocultures and in rMC-1 and pericyte cocultures grown in HG medium. Importantly, when rMC-1 transfected with Cx43 siRNA were grown as cocultures with pericytes, a significant decrease in GJIC, and increase in TUNEL-positive cells was observed, concomitant with decreased Akt phosphorylation. Upregulation of Cx43 rescued rMC-1 from HG-induced apoptosis. Conclusions Gap junction communication between Muller cells and pericytes is essential for their survival. Downregulation of Cx43 that is HG induced and impairment of GJIC activity in Muller cells contributes to loss of glial and vascular cells associated with the pathogenesis of diabetic retinopathy.
A new species of Peperomia (Piperaceae) from Venezuela

Peperomia boomii Steyermark is described from an area of igneous rocks in the northwestern sector of the state of Bolivar, Venezuela. It is compared withP. pseudodependens, P. turboensis, andP. lanceolato-peltata.
Discharge response to channelization of a coastal plain stream

The Obion River in western Tennessee was channelized by the U.S. Army Corps of Engineers in the 1960s. The primary purpose was to reduce flooding that inhibits agricultural productivity in the lower bottomlands. Channel enlargement and straightening has improved hydraulic efficiency. The increase in water velocity has effectively decreased flooding in the upper sections of the Obion River. However, runoff from the channelized portion of the drainage basin converges at downstream locations faster than the stream channel can accommodate, resulting in higher peak discharges and an increase in flood frequency. During the growing season months (May–October), the number of floods on the lower Obion River increased 140 percent following channelization. The greater flow efficiency allows water to move rapidly out of the Obion River drainage, decreasing the average duration of flood events. Brief periods of inundation, however, can destroy crops; therefore, the change in flood duration caused by channelization is not a desirable alternative to the higher number of floods that also occur. Conditions for bottomland cultivation have improved in the upper channelized sections of the Obion River. However, the higher flood frequency during the growing season on the lower river segments will limit agricultural productivity, which is contrary to the initial justification for channelization.
Auditory morphological priming in the lexicon

Abstract Three auditory lexical decision experiments were conducted which investigated how morphological structure is represented in the lexicon. The first experiment showed that morphological relationships can be represented independently of semantic relatedness. A large facilitatory priming effect was found for morphologically related words that were not semantically related (e.g. submit, permit). Significant priming was not found for words that were simply phonologically related (e.g. balloon, saloon). The second and third experiments indicated that suffixes do not have lexical representations that can be primed during lexical access; morpholgical priming was not found between words that shared a suffix (e.g. joking, typing). Formal models which propose separate lexical entries for affixes are not supported. Finally, phonological priming was observed when words shared a final syllable but not when they simply shared final segments. Models of word recognition which include a level of syllabic representa...
Improvement of optical depth relations to PM2.5 concentrations using lidar derived PBL heights

To provide reasonable forcasts of near surface PM2.5 levels, it necessary that satellite measurments provide a reasonable estimator of PM2.5 which can be coupled to a transport model. Unfortunately this requires that the aerosol be homogeneously mixed and that the extent of the PBL be sufficiently accurate. For example, the IDEA product (Infusing satellite Data into Environmental Applications) used by the EPA relies on a static relationship connecting PM2.5 to MODIS aerosol optical depth (AOD) which relies on a static model of the PBL aerosol height. In this paper, we show that the PBL height is far from static and by taking the variable PBL into account, a better prediction of PM2.5 from the MODIS (AOD) measurements is obtained. In addition, seasonal variations in the microphysical properties are also demonstrated and accounting for the additional variability further improves the PM25/AOD slope predictor.
dc: A live webcast control system

Live Internet streaming media programs, called webcasts, can adopt techniques developed by television to obtain higher quality. We have developed a general webcast production model composed of three stages (i.e., sources, broadcast, and transmission) and a tool, called the Director's Console (dc), to control live webcasts. The tool is one component of a distributed service architecture, which adapts to varying physical infrastructure and broadcast configurations.
Cems investigations of reactions at buried MoS2−Fe interfaces

Understanding the chemistry at buried MoS2−Fe interfaces is important since it impacts on the adhesion and wear characteristics of lubricant-substrate systems. To probe those syntems, conversion Electron Mossbauer Spectroscopy (CEMS) was employed to provide nondestructive characterization of the chemistry and crystallographic orientation at the interface.
Toward A Computational Model Of IP3R1-associated Ataxia

Individuals with ataxia suffer impaired imbalance and incoordination of motor functions. Approximately 150,000 Americans are afflicted with ataxia, as are thousands of individuals worldwide. Among these are families with reduced levels of IP3R1 protein, the primary receptor for IP3 in cerebellar Purkinje neurons. Mice with reduced levels of IP3R1 are also ataxic; cerebellar microsomes from IP3R1 knockout mice exhibit little calcium release when probed with IP3. This suggests that altered calcium response to IP3 may mediate the pathophysiology of cerebellar ataxia associated with reduced IP3R1. Currently, there are no direct therapeutics for hereditary ataxias. We hypothesized that adjusting IP3R1 sensitivity to IP3 in the context of reduced IP3R1 could restore normal calcium response. To investigate our hypothesis, we adapted a computational compartmental model of a cerebellar Purkinje neuron previously published by our laboratory, using optimal parameters for calcium release. These parameters were dependent on the shape of the IP3 signal produced from PIP2 hydrolysis, determined in a recent study published by our group. In our optimized model, we reduced the value of Jmax, the variable representing IP3R1 abundance in Purkinje spines, to 50%, 40%, 30%, 20%, and 10% of the normal level of IP3R1 found in mouse cerebellum. Next, we adjusted the sensitivity of IP3R1 to IP3 in a similar cumulative fashion to see whether increasing sensitivity could rescue low abundance. We did this by varying values for dIP3, the dissociation constant for IP3 from the receptor. We found that correspondent increases in IP3R1 sensitivity to IP3 restored normal calcium response when IP3R1 abundance was reduced to as low as 30% of its normal value. This promises significant therapeutic benefit for individuals with ‘IP3R1-associated ataxia’, as the phosphorylation status of IP3R1 can be regulated experimentally to adjust its sensitivity. (Supported by NIH RR013186)
Cooperative education, career exploration, and occupational concepts for community college students☆

Abstract Super's self-concept theory of career development and Jordaan's construct of vocational exploratory behavior were used to investigate the outcomes of a college cooperative education program. The effects of an internship were compared with those of a classroom experience with regard to change in similarity between self- and occupational pictures (incorporation scores). A measure of incorporation was administered to 85 students who worked during one quarter, and 99 students who were enrolled in classes during the same period. Both groups increased in incorporation for prospective occupation (t = .01, p > .10). For the internship group no difference was found between increase in incorporation for first- and second-choice occupation (t = .24, p > .10), while for the classroom group the increase in incorporation for prospective occupation was significantly greater than for second-choice (t = 2.80, p
Association of immunosuppressant-induced protein changes in the rat kidney with changes in urine metabolite patterns: a proteo-metabonomic study.

The basic mechanisms underlying calcineurin inhibitor (CI) nephrotoxicity and its enhancement by sirolimus are still largely unknown. We investigated the effects of CIs alone and in combination with sirolimus on the renal proteome and correlated these effects with urine metabolite pattern changes. Thirty-six male Wistar rats were assigned to six treatment groups (n=4/group for proteome analysis and n=6/group for urine 1H-NMR metabolite pattern analysis): vehicle controls, sirolimus 1mg/kg/day, cyclosporine 10mg/kg/day, cyclosporine 10mg/kg/day + sirolimus 1mg/kg/day, tacrolimus 1mg/kg/day, tacrolimus 1mg/kg/day + sirolimus 1mg/kg/day. After 28 days, 24h-urine was collected for 1H-NMR-based metabolic analysis and kidneys were harvested for 2D-gel electrophoresis and histology. Cyclosporine affected the following groups of proteins: calcium homeostasis (regucalcin, calbindin), cytoskeleton (vimentin, caldesmon), response to hypoxia and mitochondrial function (prolyl 4-hydroxylase, proteasome, NADH dehydrogenase) and cell metabolism (kidney aminoacylase, pyruvate dehydrogenase, fructose-1,6-bis phosphate). Several of the changes in protein expression, confirmed by Western blot, were associated with and explained changes in metabolite concentrations in urine. Representative examples are an increase in kidney aminoacylase expression (decrease of hippurate concentrations in urine), up regulation of pyruvate dehydrogenase and fructose-1, 6-bisphosphatase, (increased glucose metabolism) and down regulation of arginine:glycine-amidino transferase (most likely due to an increase in creatinine concentrations). Protein changes explained and qualified immunosuppressant-induced metabolite pattern changes in urine.
THE FINE STRUCTURE OF THE SUPRAMEDULLARY NEURONS OF THE PUFFER WITH SPECIAL REFERENCE TO ENDOCELLULAR AND PERICELLULAR CAPILLARIES.

Many capillaries are embedded in the cytoplasm of large supramedullary neurons (about 200 to 300 μ in diameter). Fewer such capillaries are seen in the smaller neurons (about 80 to 100 μ in diameter). The neuron clusters remain unstained after vital staining with trypan blue indicating presence of the blood-brain barrier. Electron microscopic studies show that the capillary lumen is lined by nonfenestrated endothelial cells, pericytes, and a continuous basement membrane. Glial cell processes consisting mostly of astrocytes abut onto the capillary basement membrane separating the capillary from the neuron. The continuous glial investment around blood vessels may play a role in maintenance of the blood-brain barrier. The nucleus in supramedullary cells is roughly circular and contains one large and several small nucleoli. The perikaryon contains neurofilaments, diffusely distributed elements of endoplasmic reticulum, clusters of RNP granules, Golgi complex, mitochondria, multivesicular bodies, and inclusion bodies; but is devoid of elementary neurosecretory granules. The cell body of the neuron is entirely covered by glial cells, often with processes which deeply indent the soma surface. Neither synapses nor arborizing dendrites are found on the cell body.
Computational methodology to predict damage growth in unidirectional composites—II. Case studies

Abstract A computational methodology was used to simulate the damage growth processes in center notched unidirectional Boron-Epoxy, Boron-Aluminum, and Silicon Carbide-Titanium composites subjected to quasi-static tensile loading. This methodology uses a specially developed finite element program, Micromechanics Analysis and Damage Growth In Composites (MADGIC) code and a hybrid micromechanical-anisotropic continuum model. The unique feature of the approach is that multiple modes of damage can be simulated simultaneously and the crack path need not be preselected. The direction and path of damage growth are dictated by the local mechanics in conjunction with the failure criteria. This paper reports on the applications of this computational methodology to several case studies. Predictions of the damage growth process in unidirectional aluminum and titanium matrix composites were correlated with experimental observations, which have shown to be highly dependent on the properties of the constituents. The computational simulations captured the salient features of the observed notch-dip damage evolution in each of the materials evaluated. The predictions agreed qualitatively quite well with the experimental observations of the failure process.
Development of consolidated in-situ metallization processes for enhanced productivity

Backend metallization processes routinely consist of three separate steps when metallic barrier layers are sputtered: (1) deposition of the primary, conducting metal layer, (2) removal from the deposition system, and (3) deposition of a capping layer of a different metal, usually a metallic anti-reflective (ARC) coating. Physical sputtering systems sometimes are not configured to deposit the metal layers sequentially (insitu) without removal from the system, even though these modern tools have multiple chambers. This paper details how different metallization processes were consolidated to eliminate the air break between the primary conducting layer, typically Al or Cu, and the capping layers. This paper details the motivation, characterization, development, and electrical results of these new insitu processes for separate technologies on an Applied Materials Endura 5500 PVD. The motivation for backend process consolidation consisted of significant cycle time reduction, reduced cost of ownership across multiple tools, and reduced chance of depositing wrong capping layers. Wafer scrap risk and process integration is detailed for developing the insitu depositions for the A1CuW/TiN ARC stack. Optimization and characterization of the multiple step A1CuW deposition has been detailed previously [1] and is used as basis for this work. The concerns for both metal 1 and metal 2 A1CuW layers are described in addition to possible impact on existing photolithography and metal etch processes corresponding to these metal layers. Results show no significant difference in the critical dimensions after develop and after metal etch on both metal layers for the insitu AICuW ITiN ARC process even though there was a 32% increase in the insitu A1CuW ITiN stack reflectivity compared to the standard stack A1CuW ITiN ARC process. Data is presented showing throughput increased by close to 20% using the insitu AICuW ITiN ARC process compared to the standard process for both metal stack layers. Cycle time reduction and reduced cost of equipment ownership was achieved without any decrease in wafer die probe yield or significant change to existing photolithography and etch processes.
University of Wisconsin solution for human donor heart preservation: initial clinical experience.

Abstract Although in vitro and primate orthotopic transplant experiments have suggested the superiority of University of Wisconsin solution (UWS) compared with crystalloid cardioplegia and saline solution storage for hypothermic heart preservation, concerns about the viscosity and the high potassium concentration of UWS have precluded its use in human cardiac transplantation. To test the safety and efficacy of UWS, 16 patients received hearts arrested with, flushed with, and stored in UWS at 4 °C for a mean ischemic time of 153.3 ± 30.7 minutes. After reperfusion, the hearts contracted vigorously and attained a stable sinus rhythm within 4.0 ± 2.4 minutes, and the patients were weaned from bypass in 24.5 ± 8.0 minutes. There was no evidence of acute or chronic ischemic myocardial injury by enzymatic analysis, electrocardiography, or biopsy specimen histology. The results suggest UWS can be safely used, within currently accepted limits of donor ischemic time, to arrest and preserve human hearts for transplantation. Further studies of preservation are required to compare UWS with crystalloid cardioplegia and saline solution storage and to test the ability of UWS to prolong the period of safe donor hypothermic ischemia in clinical heart transplantation.
Functional MRI in human somatosensory cortex activated by touching textured surfaces

MRI revealed activation foci in human somatosensory cortex during protocols involving stimulation of the fingertips with a textured surface. A 2D T2*-weighted gradient echo sequence was used to acquire images. The imaging protocol included acquiring images while subjects performed specific tactile stimulation paradigms (activation scans) or rested. Three different paradigms were used to produce functional activation using a textured surface to rub the fingertips of one hand. First, motor sensory activation was produced by rubbing the textured surface held in one hand against the fingertips of the opposite hand only during the activation scans. Second, the hand holding the textured surface moved throughout the experiment but touched the fingertips of the opposite hand only during the activation scans. Third, subjects remained still in the magnet throughout the entire study while an investigator rubbed the textured surface against the subjects' fingertips during the activation scans. Images were postprocessed using a cross-correlation scheme. The results revealed multiple foci of motor sensory activation near the central sulcus, postcentral sulcus, and prefrontal cortex.
Level of agreement between DIS and UM-CIDI alcohol and marijuana use disorders: Implications for research

By and large, recent epidemiological investigations of alcohol and drug use disorders are based on structured interviews, such as the Diagnostic Interview Schedule (DIS) and the Composite International Diagnostic Interview (CIDI), which are designed to be administered by trained lay interviewers. Little is known about the level of agreement between these instruments. To fill this gap, we compared responses from 971 young adults from an epidemiological sample, who were administered both the DIS and the University of Michigan CIDI (UM-CIDI) in the same interview session. Level of agreement was estimated for responses to individual items, and for DSM-IIIR abuse/dependence (A/D) diagnoses and symptoms for alcohol and marijuana. DIS/UM-CIDI agreement for drug use disorders in the year preceding the interview was moderate for each disorder (alcohol A/D, kappa = 0.58; marijuana A/D, kappa = 0.68), although one-year prevalences of alcohol and marijuana A/D were approximately 40% higher for the DIS compared to the UM-CIDI. Despite the discrepancies, levels of comorbidity with other psychiatric disorders and associations with risk factors were similar for the DIS and UM-CIDI. Copyright © 1999 Whurr Publishers Ltd.
Charges on semiconducting nanotubes in polar media: Polarons and excitons

Abstract Charge carriers on semiconducting nanotubes immersed in the polar medium such as polar solvents undergo self-trapping into polarons. In the effectively 1d regime polarons are found to have binding energies of approximately 30–35% of the binding energy of excitons. As the thermal dissociation of excitons would occur into polaron pairs, the thermal ionization energy of excitons is substantially reduced, which is expected to lead to enhanced separation of charges.
The Impact of Obesity and Metabolic Syndrome on Chronic Hepatitis C

The metabolic syndrome and the hepatitis C virus (HCV) infection are 2 global health care challenges with a complex interaction. Insulin resistance, a central component of the metabolic syndrome, is epidemiologically and pathophysiologically intrinsically linked to HCV infection. Insulin resistance and diabetes affect clinical outcomes in patients with liver disease related to HCV, namely, incidence of hepatocellular carcinoma, liver-related mortality, fibrosis progression rate, response to antiviral therapy, and possibly the incidence of cardiovascular events. Viral and metabolic steatosis and its interactions with HCV and the metabolic syndrome are discussed. Management and the need for further research conclude the article.
A two-site kinetic mechanism for ATP binding and hydrolysis by E. coli rep helicase dimer bound to a single-stranded oligodeoxynucleotide

Escherichia coli Rep helicase catalyzes the unwinding of duplex DNA in reactions that are coupled to ATP binding and hydrolysis. We have investigated the kinetic mechanism of ATP binding and hydrolysis by a proposed intermediate in Rep-catalyzed DNA unwinding, the Rep “P2S” dimer (formed with the single-stranded (ss) oligodeoxynucleotide, (dT)16), in which only one subunit of a Rep homo-dimer is bound to ssDNA. Pre-steady-state quenched-flow studies under both single turnover and multiple turnover conditions as well as fluorescence stopped-flow studies were used (4 °C, pH 7.5, 6 mM NaCl, 5 mM MgCl2, 10 % (v/v) glycerol). Although steady-state studies indicate that a single ATPase site dominates the kinetics (kcat=17(±2) s−1;KM=3 μM), pre-steady-state studies provide evidence for a two-ATP site mechanism in which both sites of the dimer are catalytically active and communicate allosterically. Single turnover ATPase studies indicate that ATP hydrolysis does not require the simultaneous binding of two ATP molecules, and under these conditions release of product (ADP-Pi) is preceded by a slow rate-limiting isomerization (∼0.2 s−1). However, product (ADP or Pi) release is not rate-limiting under multiple turnover conditions, indicating the involvement of a second ATP site under conditions of excess ATP. Stopped-flow fluorescence studies monitoring ATP-induced changes in Rep’s tryptophan fluorescence displayed biphasic time courses. The binding of the first ATP occurs by a two-step mechanism in which binding (k+1=1.5(±0.2)×107M−1s−1, k−1=29(±2) s−1) is followed by a protein conformational change (k+2=23(±3) s−1), monitored by an enhancement of Trp fluorescence. The second Trp fluorescence quenching phase is associated with binding of a second ATP. The first ATP appears to bind to the DNA-free subunit and hydrolysis induces a global conformational change to form a high energy intermediate state with tightly bound (ADP-Pi). Binding of the second ATP then leads to the steady-state ATP cycle. As proposed previously, the role of steady-state ATP hydrolysis by the DNA-bound Rep subunit may be to maintain the DNA-free subunit in an activated state in preparation for binding a second fragment of DNA as needed for translocation and/or DNA unwinding. We propose that the roles of the two ATP sites may alternate upon binding DNA to the second subunit of the Rep dimer during unwinding and translocation using a subunit switching mechanism.
Fully stratified compact hypersurfaces in Minkowski 4-space

A compact hypersurface in Minkowski space decomposes as a disjoint union of loci where the induced metric is: definite, degenerate, or indefinite. Here we deduce several global properties of the hypersurface from properties of its degenerate loci.
Amino acid sequence around the active-site selenocysteine of rat liver glutathione peroxidase.

Abstract Glutathione peroxidase (glutathione:hydrogen-peroxide oxidoreductase, EC 1.11.1.9) from rat liver was purified to at least 95% purity. A peptide of 16 amino acids, including the active-site selenocysteine (SeCys) residue, was isolated from a tryptic digest by reverse-phase HPLC and gel filtration. The amino acid sequence of the first 46 residues of glutathione peroxidase was obtained from the overlapping sequences of the tryptic selenopeptide and the intact subunit. The selenocysteine residue was located at residue 41, and the sequence of the tryptic selenopeptide was Val-Leu-Leu-Ile-Glu-Asn-Val-Ala-Ser-Leu-SeCys-Gly-Thr-ThrThr-Arg. The sequence was analyzed by computer for homology with other proteins, but no closely related sequences were found. Glutathione peroxidase is the first selenoprotein for which sequence data have been obtained, and the methods described should be applicable to mapping and to sequence analysis of Se-containing peptides from other selenoproteins.
Plant-species richness in corridor intersections: is intersection shape influential?

Corridor intersections constitute nodes that can be more mesic than the intersecting corridors themselves. Such microclimatic conditions may lead to an “intersection effect,” in which plant richness is higher in the intersection than in the corridors. We hypothesized that an additional factor contributing to intersection effects is the movement of plants along corridors into intersections by way of bird- and mammal-dispersed seeds. If this hypothesis is correct, one would expect intersection-shape effects, defined herein as differences in intersection section richness associated with the number of possible avenues for plant influx into the intersection. Specifically, richness in intersections should be lowest for L-shape intersections (two avenues), higher for T-shape intersections (three avenues), and highest for X-shape intersections (four avenues). We used data from fencerow networks to test this hypothesis about corridor intersections. During October 1992 and March 1993, we determined woody- and herbaceous-plant richness for 25 intersections and their associated fencerows in central Texas, USA. We compared two measures of intersection richness among the three intersection shapes: richness of plants dispersed primarily by birds and mammals (vertebrate-dispersed plant richness), and richness of plants dispersed primarily by wind, ants or other means (non-vertebrate dispersed plant richness). Vertebrate-dispersed plant richness differed significantly among intersection shapes, but no differences in nonvertebrate dispersed plant richness were evident, which is what one would expect if the number of avenues for vertebrate vectors into an intersection was an important factor influencing intersection richness. The intersection-shape effects we found were not attributable to fencerow features (amount of woody cover, width, pressence of breaks) or intersection characteristics (amount of woody cover, size, distance to nearest connected intersection or patch). Our results from fencerow networks support the hypothesis that intersection effects on plant richness are influenced by intersection shape via the number of intersecting corridors. Understanding patterns and processes that occur in networks is important for conservation biologists because intersections in networks have the potential to function as refugia for plant species that require conditions more mesic than those of the surrounding matrix. Networks also may be valuable asin situ sources of seed for managers attempting to restore plant communities in the matrix.
Identification of Aim-1 as the underwhite mouse mutant and its transcriptional regulation by MITF.

Animal pigmentation mutants have provided rich models for the identification of genes modulating pathways from melanocyte development to melanoma. One mouse model is theunderwhite locus, alleles of which manifest altered pigmentation of both eye and fur, sometimes in an age-dependent fashion. Here we show that the mouse homolog of a recently identified gene whose mutation produces Japanese gold-colored fish, medaka b, maps to the mouseunderwhite locus. We identify distinct mutations of this gene, known as Aim-1, in three underwhite mouse alleles and find that structure/function differences correlate with recessive versus dominant inheritance. The human ortholog of AIM-1 was originally identified as a melanocyte-restricted antigen that is recognized by autologous T cells from a patient with melanoma. We also provide evidence that AIM-1 is transcriptionally modulated by MITF, a melanocyte-specific transcription factor essential to pigmentation and a clinical diagnostic marker in human melanoma. Although AIM-1 appears to reside downstream of MITF, chromatin immunoprecipitations do not reveal binding of MITF to a 5′-flanking region containing histone 3 acetylation, indicating that MITF either acts indirectly on AIM-1 or it binds to a remote regulatory sequence. Nevertheless, MITF links AIM-1 expression and theunderwhite phenotype to a transcriptional network central to pigmentation in mammals.
Dopamine concentrations in the rat brain following injections into the substantia nigra of baclofen, γ-aminobutyric acid, γ-hydroxybutyric acid, apomorphine and amphetamine

Systemic administration of dl-baclofen (20–80 mg/kg) and γ-butyrolactone (250–500 mg/kg) increased the concentration of dopamine but not of norepinephrine in the rat forebrain. These drugs caused an equivalent increase in the concentration of dopamine in the striatum and olfactory tubercle, regions containing terminals of nigrostriatal and mesolimbic dopaminergic neurones, respectively. When injected directly into substantia nigra (A9), GABA, γ-hydroxybutyrate and baclofen increased the dopamine concentration in the forebrain; apomorphine and d-amphetamine were without effect. When injected into the medial portion of the ventral tegmentum (A10) baclofen increased the dopamine concentration in the olfactory tubercle and nucleus accumbens. Following intracerebral injections, dl-baclofen was several hundred times more potent than GABA, and most of the activity of baclofen resided in the l-isomer. Intracerebral injections of picrotoxin antagonized the ability of GABA but not of baclofen to increase the striatal concentration of dopamine. After unilateral intranigral injections of GABA, γ-hydroxybutyrate and baclofen rats circled away from the side of the drug injection.
Strategies for stationary and portable fuel cell markets

Abstract In the future, hydrogen-based stationary and portable fuel cell systems can help supply some or all of the power demanded with additional advantages of higher reliability, lower emissions, independence from the general grid, and cogeneration capability. In order to understand how to prepare the future for this technology, this paper describes a thorough investigation of past alternative stationary and portable power projects in order for an assessment of the opportunities for stationary and portable fuel cell markets, as well as interactions with transportation hydrogen systems. The lessons learned from the programs are used to establish best practices and recommendations for a hydrogen strategy that addresses opportunities for hydrogen in power generation systems, as well as to make recommendations for market transformation within the hydrogen fuel cell industry.
Peri-Implant Cystic Lesion With Unusual Cellular Changes: A Case Report

Introduction: This report describes the history and management of a cyst developing in anatomic contact with an immediately placed dental implant.Case Presentation: The lesion presented clinically as a facial swelling of the gingiva adjacent to an osseointegrated and restored maxillary right lateral incisor implant. Radiographs showed a well-circumscribed radiolucency, which was contiguous with the implant surface. After reflection of a mucoperiosteal flap, the lesion was enucleated in toto, and the defect was curetted. The bony defect was grafted, and the lesional tissues were sent for histologic analysis. The results demonstrated the presence of a cyst of unknown origin with some unusual cellular changes in localized areas of the cyst lining resembling ameloblasts. Healing occurred uneventfully, and the patient was monitored for recurrence. At the 2-year follow-up appointment, the patient presented no clinical or radiographic signs of recurrence of the lesion. The etiology of this lesion is unknown.Conc...
Linkage of preaxial polydactyly type 2 to 7q36

We have characterized a 6-generation North American Caucasian kindred segregating one form of preaxial polydactyly type 2 (PPD-2). We demonstrate linkage to the 7q36 region and describe a submicroscopic telomeric chromosomal deletion in phase with the PPD-2 phenotype. Recently, several kindreds segregating triphalangeal thumb (TPT) with and without associated hand anomalies (syndactyly and/or postaxial polydactyly) have also been linked to the subtelomeric region of chromosome 7q. We demonstrate by haplotype analysis that our North American pedigree represents a PPD allele that is independent of the founder PPD allele present in the previously described kindreds. 23 refs., 5 figs., 2 tabs.
Two soybean ribulose-1,5-bisphosphate carboxylase small subunit genes share extensive homology even in distant flanking sequences

Soybean contains a multigene family which encodes the small subunit of ribulose-1,5-bisphosphate carboxylase (RuBPCss). A member of this gene family, SRS4, has been isolated from a soybean genomic DNA library. Its nucleotide sequence has been determined and compared to the sequence of SRS1, a previously characterized RuBPCss gene from soybean. Relevant regulatory sequences such as the PuPuCCAAT boxes, TATA box, the actual start of transcription and poly A addition sites are conserved between the two genes. Using a gene specific synthetic probe to the 3′ flanking region the steady state mRNA levels of SRS4, like SRS1, are shown to be very high in light grown soybean seedlings and low in seedlings grown in darkness. SRS1 and SRS4 are very closely related, the three exons being 96%, 93% and 96.5% homologous in nucleotide sequence. The polypeptide sequences are nearly identical with only one amino acid change in each of the three exons encoding the 178 amino acid precursor polypeptide. The two introns are about 75% homologous and the flanking regions are more than 85% homologous (700 base pairs on the 5′ end and 300 base pairs on the 3′ end). Furthermore, hybridization studies between lambda clones containing the SRS1 and SRS4 genes reveal that a region of strong homology extends at least 4 kb on the 5′ end and about 1.1 kb on the 3′ end. We propose that these two genes may be alloalleles or homeologous alleles. This proposal is consistent with soybean having an allotetraploid origin, and would imply that the divergence of two ancient Papilionoidae species gave rise to these two genes.
Surgical factors in pediatric cochlear implantation and their early effects on electrode activation and functional outcomes.

Multiple factors likely influence speech perception and language outcomes after early cochlear implantation (1,2). Medical, surgical, and anatomic factors may contribute to variability in these outcomes as suggested by the influence of electrode position on speech perception results in adults (3,4). Although long-term morbidity rarely results from perioperative complications (5–7), the long-term effects on device function and patient outcome are less clear. The present report examines whether optimization of surgical implantation represents an opportunity for greater implant benefit. We considered surgery-related variables, including cochlear anatomy, cause, and complications alongside other child, environmental, and device variables to assess effects on auditory behavior and receptive language at 2 years after surgery. Our goal was to examine how surgical factors relate to device function and their early effects on auditory performance and verbal language comprehension.
On common values of φ(n) and σ(m). I

We show, conditional on a uniform version of the prime k-tuples conjecture, that there are x/(log x)1+o(1) numbers not exceeding x common to the ranges of φ and σ. Here φ is Euler’s totient function and σ is the sum-of-divisors function.
CONTINUOUS EXTENSIONS ARE NOT HÖLDER

Let Q denote a quadratic polynomial and A∞ the super-attracting basin of Q at the point ∞ on the Riemann sphere . There exists a unique Riemann mapping Φ from the open disk onto A∞ such that Φ(∞)=∞, Φ'(∞)=1 and Φ-1 conjugates Q:A∞→A∞ to the squaring map S:D→D:z↦z2. In this paper, we show if Q is real and infinitely renormalizable of bounded type then the continuous extension of Φ to the closed disk cannot have any Holder continuity on the boundary circle .
Amaranthus hybridus can be pollinated frequently by A. tuberculatus under field conditions

Recent studies have confirmed that weedy Amaranthus species are capable of interspecific hybridization, and such hybridization may foster the evolution of herbicide resistance. However, the extent to which hybridization among these species occurs in nature is unknown. The purpose of this study was to determine the frequency under field conditions at which A. hybridus, a monoecious and predominantly self-pollinated species, would be pollinated by A. tuberculatus, a dioecious species. To do this, parents carrying different alleles at the ALS locus, which encodes a herbicide target site, were used. Male A. tuberculatus parents were homozygous for a dominant herbicide-insensitive allele, while A. hybridus parents were homozygous for a sensitive form. Hybrid progeny therefore could be detected via herbicide selection. Mean hybridization frequencies between 0.4 and 2.3% were obtained, depending on the proximity between parents (P=0.02). The robustness of the hybrid selection assay was verified using a molecular marker and DNA content analyses. Using these techniques, more than 99% of the progeny that survived the herbicide were confirmed to be hybrids. Frequencies obtained in this study were many times higher than the generally expected rate of mutation. Therefore, even minimal fertility in hybrid progeny would support the view that hybridization could play a role in adaptive evolution of weedy Amaranthus species.