cssi/SciSciGPT-SciSciNet huggingface dataset:
A Role for Tectal Midline Glia in the Unilateral Containment of Retinocollicular Axons

Retinal fibers approach close to the tectal midline but do not encroach on the other side. Just before the entry of retinal axons into the superior colliculus (SC), a group of radial glia differentiates at the tectal midline; the spatiotemporal deployment of these cells points to their involvement in the unilateral containment of retinotectal axons. To test for such a barrier function of the tectal midline cells, we used two lesion paradigms for disrupting their radial processes in the neonatal hamster: (1) a heat lesion was used to destroy the superficial layers of the right SC, including the midline region, and (2) a horizontally oriented hooked wire was inserted from the lateral edge of the left SC toward the midline and was used to undercut the midline cells, leaving intact the retinorecipient layers in the right SC. In both cases, the left SC was denervated by removing its contralateral retinal input. Animals were killed 12 hr to 2 weeks later, after intraocular injections of anterograde tracers to label the axons from the remaining eye. Both lesions resulted in degeneration of the distal processes of the tectal raphe glia and in an abnormal crossing of the tectal midline by retinal axons, leading to an innervation of the opposite (“wrong”) tectum. The crossover occurred only where glial cell attachments were disrupted. These results document that during normal development, the integrity of the midline septum is critical in compartmentalizing retinal axons and in retaining the laterality of the retinotectal projection.
Recurrent intestinal metaplasia after radiofrequency ablation for Barrett’s esophagus: endoscopic findings and anatomic location

Background Radiofrequency ablation (RFA) is a safe and effective treatment for Barrett's esophagus (BE) that results in high rates of complete eradication of intestinal metaplasia (CEIM). However, recurrence is common after CEIM, and surveillance endoscopy is recommended. Neither the anatomic location nor the endoscopic appearance of these recurrences is well-described. Objective Describe the location of histologic specimens positive for recurrence after CEIM and the testing performance of endoscopic findings for the histopathologic detection of recurrence. Design Retrospective cohort. Setting Single referral center. Patients A total of 198 patients with BE with at least 2 surveillance endoscopies after CEIM. Interventions RFA, EMR, surveillance endoscopy. Main outcome measurements The anatomic location and histologic grade of recurrence. Results In a mean 3.0 years of follow-up, 32 (16.2%; 95% confidence interval [CI], 11.0%-22.0%) patients had recurrence of disease, 5 (2.5%; 95% CI, 0.3%-4.7%) of whom progressed beyond their worst before-treatment histology. Recurrence was most common at or near the gastroesophageal junction (GEJ). Recurrence>1 cm proximal to the GEJ always was accompanied by endoscopic findings, and random biopsies in these areas detected no additional cases. The sensitivity of any esophageal sign under high-definition white light or narrow-band imaging for recurrence was 59.4% (42.4%, 76.4%), and the specificity was 80.6% (77.2%, 84.0%). Limitations Single-center study. Conclusion Recurrent intestinal metaplasia often is not visible to the endoscopist and is most common near the GEJ. Random biopsies>1 cm above the GEJ had no yield for recurrence. In addition to biopsy of prior EMR sites and of suspicious lesions, random biopsies oversampling the GEJ are recommended.
A paired comparison of two precipitation chemistry sites in East-Central Mississipi

Abstract A paired comparison was performed on 2 years of precipitation chemistry data from Meridian and Newton, MS. The Meridian site is in violation of several National Atmospheric Deposition Program siting criteria, whereas the Newton site, 35 km west, is mostly in compliance. The two sites are compared through the use of volume-weighted means, deposition, logarithmic distributions, boxplots, paired t-tests, the nonparametric Wilcoxon test, and a form of linear regression analysis that accounts for cases in which both populations are subject to error. Results indicate Meridian has higher concentrations of all measured ions except NH4+. Elevated NH4+ concentrations at Newton are most likely due to the location of the site in a cattle pasture. Significant differences (95% confidence level) were found for Cl−, Na+, K+, Ca2+ and Mg2+. SO42− was found to be borderline significant.
Definition of the Pulmonary Antibody Response to Ovalbumin following Local Challenge in Systemically Immunized Rats

AbstractThe in vivo pulmonary immune response of rats to local stimulation with antigen was assessed by measuring antigen-specific antibody and antibody-secreting cells utilizing enzyme-immunoassay technology. Sprague-Dawley rats were immunized subcutaneously with ovalbumin (OA) emulsified in Freund's incomplete adjuvant, challenged with OA intratra-cheally on Day 19 and sacrificed 1, 2, 3, or 4 days later. Specific antibody-secreting cells in the lung-associated lymph nodes were enumerated with the ELISA-SPOT assay and antibody concentration in the pulmonary lavage fluids and sera was assessed with the ELISA. The greatest response for each parameter was on Day 2. Cellular infiltration of the lung was minimal. Cellular infiltrates consisted mainly of polymorphonuclear leukocytes and were most numerous in the lavage fluid on Days 1 and 2 and in the lung parenchyma on Day 2 after challenge. Local production versus serum transudation of antibody was evaluated by comparing the levels of OA-specific antibody t...
Physical fitness cannot be used to predict the likelihood of acute coronary syndromes in ED patients with chest pain.

Abstract Objective The objective of the study was to explore the association between physical fitness and the likelihood of acute coronary syndrome (ACS) in patients presenting to the emergency department (ED) with chest pain (CP). We hypothesized that the likelihood of ACS would be lower in physically fit patients and higher in patients with exercise-induced CP. Methods The study involved a prospective, descriptive cohort in an academic suburban ED. Subjects were ED patients with CP admitted for suspected ACS. Demographic and clinical data were collected by trained research assistants using standardized forms. Patients were surveyed on level of fitness and whether they had ever experienced anginal type symptoms during exercise. Acute coronary syndrome was considered present if the patient had electrocardiographic evidence of infarction or ischemia; elevated troponin I levels; greater than 70% stenosis of culprit coronary artery; or a positive nuclear, echocardiographic, or treadmill stress test result. Patients readmitted within 30 days for reinfarction, cardiogenic shock, or arrhythmias were also considered to have ACS. The association between physical fitness and ACS was determined using χ2 tests and odds ratios (ORs). Results One hundred patients were enrolled. Mean age was 55.8 (±15.3) years; 36% were female; 85% were white. Thirteen (13%) patients had positive troponins, 22 of 36 catheterized patients had greater than 70% coronary artery stenosis, and 6 (6%) had abnormal stress test results. There were no deaths or reinfarctions within 30 days. The rate of ACS was similar in patients who were physically fit and those who were not (24% vs 37%; OR, 0.5 [95% confidence interval, 0.2-1.3]) and in patients who had experienced exercise-induced CP and those who had not (32% vs 29%; OR, 1.2 [95% confidence interval, 0.4-3.2]). Neither the frequency nor the intensity of exercise was associated with ACS. Conclusions Physically fit patients with CP were as likely to have ACS as those not physically fit. A history of exercise-induced CP was not associated with an increased likelihood of ACS.
YBX1 expression and function in early hematopoiesis and leukemic cells

Hematopoietic transcription factors play a critical role in directing the commitment and differentiation of hematopoietic stem cells along a particular lineage. Y-box protein (YBX1) is a transcription factor which is widely expressed throughout development and is involved in erythroid cell development; however, its role in early hematopoietic differentiation is not known. This study aims to investigate the role of YBX1 expression in early hematopoietic differentiation and leukemia. Here, we show that YBX1 is highly expressed in mouse erythroid myeloid lymphoid-clone 1 (EML), a hematopoietic precursor cell line, but is down-regulated in myeloid progenitors and GM-CSF-treated EML cells during the course of myeloid differentiation. Moreover, we found that lineage(-)/IL-7R(-)/c-kit(+)/Sca1(+) (LKS; enriched fraction of hematopoietic stem cells) and lineage(-)/IL-7R(-)/c-kit(+)/Sca1(-) myeloid progenitor cells showed high level of YBX1 expression as compared to the differentiated cells like granulocytes in mouse bone marrow. Also, YBX1 protein was expressed at high levels in myeloid leukemic cell lines blocked at different stages of myeloid development. We further investigated the role of YBX1 in leukemic cells by knockdown studies and observed that down-regulation of YBX1 expression in K562 leukemic cells inhibited their proliferation ability, induced apoptosis, and differentiation towards megakaryocytic lineage upon arsenic trioxide treatments relative to untreated. Overall, our data indicates that YBX1 is down-regulated during myeloid differentiation and the aberrant YBX1 expression in leukemic cells could be a contributing factor in the development of leukemia by blocking their differentiation. Thus, YBX1 protein could be an excellent molecular target for therapy in myeloproliferative disorders and leukemia.
Micro-scale Modeling of Flow and Oxygen Transfer in Hollow Fiber Membrane Bundle

Abstract The aim of this work was to develop a modeling approach to solve the flow and oxygen transfer when the blood passes through the hollow-fiber membrane bundle. For this purpose, a “two-region” modeling approach was developed regarding the hollow-fiber and blood regions. The oxygen transfer in these regions was defined with separate diffusion processes. Two-dimensional single and multi-fiber geometries were created and flow solutions were obtained for a non-Newtonian fluid. The convection–diffusion–reaction equation was solved to produce the oxygen partial pressure distributions. As a benefit of coupling the interstitial flow field into the oxygen transfer through the hollow-fiber membrane bundle, the membrane resistance was taken into consideration. Thus, varying oxygen partial pressures were observed on the outer fiber surface, which is contrary to the common simplifying assumptions of negligible membrane resistance and uniform oxygen content on the fiber surface (traditional approach). It was illustrated that, the current approach can be utilized to predict the mass transfer efficiencies without overestimating as compared to the predictions obtained with the traditional approach. Utilization of the current approach was found to be beneficial for the geometries with lower packing density which allows significant P O 2 variations on the fiber surfaces. For the geometries with dense packings, the above simplifying assumptions could be applicable. The model predictions were validated with the experimental measurements taken from a benchmark device.
Estimating locations and total magnetization vectors of compact magnetic sources from scalar, vector, or tensor magnetic measurements through combined Helbig and Euler analysis

Summary The Helbig method for estimating total magnetization directions of compact sources from magnetic vector components is extended so that tensor magnetic gradient components can be used instead. Depths of the compact sources can be estimated using the Euler equation, and their dipole moment magnitudes can be estimated using a least squares fit to the vector component or tensor gradient component data.
Self-Care Self-Efficacy, Religious Participation and Depression as Predictors of Poststroke Self-Care Among Underserved Ethnic Minorities.

Underserved ethnic minorities have multiple chronic disease risk factors, including tobacco, alcohol and substance use, which contribute to increased incidence of stroke. Self-efficacy (self-care self-efficacy), religious participation and depression may directly and indirectly influence engagement in post stroke self-care behaviors. The primary aim of the present study was to investigate the effects of self-care self-efficacy, religious participation and depression, on tobacco, alcohol and substance use in a sample of largely ethnic minority, underserved stroke survivors (n=52). Participants previously recruited for a culturally tailored secondary stroke prevention self-care intervention were included. The treatment group received three stroke self-care sessions. The usual care group completed assessments only. Both groups were included in these analyses. Main outcome measures included tobacco, alcohol and substance use. Self-care self-efficacy, religious participation and depression were also assessed. Logistic regression analyses, using self-efficacy, religious practice and depression as the referents, were used to predict binary outcomes of tobacco, alcohol and substance use at 4-weeks post-stroke. Higher depression and self-care self-efficacy were associated with reduced odds of smoking and substance use. Greater participation in religious activities was associated with lower odds of alcohol use. We can conclude that incorporating depression treatment and techniques to increase self-care self-efficacy, and encouraging religious participation may help to improve stroke self-care behaviors for underserved and low socioeconomic status individuals. Results are discussed in the context of stroke self-management.
Ankle Stability in Simulated Lateral Ankle Ligament Injuries

Background: We performed a laboratory-based study of the ankle-hindfoot complex in normal cadaveric ankles with simulated lateral ankle ligament injuries, utilizing an ankle stability testing device. The ankle stability testing device distinguished between intact, injury to anterior talofibular ligament (ATFL) and combined injury to ATFL and calcaneofibular ligament (CFL). Materials and Methods: Ankles were tested in an ankle stability testing device, with a specified inversion torque applied through the range of sagittal plane motion, then internal rotation torque applied through the entire range of sagittal plane motion. Three-dimensional motion of the calcaneus and talus in relation to the tibia were determined with a magnetic tracking system. The specimens were tested in the intact condition, then after sectioning the ATFL, then the CFL. Results: Upon sectioning the ATFL, there was a significant increase in the internal rotation motion at the tibiotalar joint. Subsequent sectioning of the CFL did not ...
The Affirmative Action and Social Policy Views of a Select Group of White Male Private High School Students.

This study investigates race views of students from a Midwestern, predominantly White, all-male high school. Findings corroborate a belief that students at the pre-sophomore college level lack a proper understanding of affirmative action (AA). Forty-three percent (n = 266) lacked knowledge altogether, whereas 30% (n = 188) opposed AA as a job hiring and promotion (out-come) measure. Conversely, a majority of students (n = 394, 65%) supported AA as an academic scholarship (front-end) measure, compared to those opposed (n = 188, 30%). When using a .05 alpha criterion, significant differences were shown for relationships between (a) job-hiring AA and age of student, grade average, and four selected social policy variables, and (b) academic scholarship AA and five of the social welfare indices. Five of the eleven relationships disappeared, however, when a stricter .01 rule was applied. In spite of the school's elitist reputation, students were supportive of multicultural education, adding credence to the argu...
The thermal structure of Jupiter; II, Observations and analysis of 8-14 micron radiation

Observations of Jovian limb structure at 8.11 and 8.45 microns are reported. These are used along with other limb structure and spectral data in the 8-14 micron region to derive a model of the thermal and cloud structure within the 1.0-0.01 bar pressure regime. The temperature is about 165 K at 1.00 bar, 108 K at 0.10 bar, and 143 K at 0.03 bar. In zones, an optically opaque cloud of NH3 exists near the 143 K (0.60 bar) level. A partly transparent haze of solid NH3 particles overlies the cloud. Belts are free of the cloud and have a much lower abundance of NH3 haze than the zones. The data are consistent with an NH3 gas abundance defined by saturation equilibrium, with a mixing ratio of 0.00015 deep in the atmosphere, and with a CH4 mixing ratio of 0.002, about three times the currently accepted value.
Spontaneous action potential activity in isolated dorsal root ganglion neurons from rats with a painful neuropathy

One of the physiological changes accompanying neuropathic pain from nerve injury is the spontaneous firing of primary afferent fibers. At least some of this activity is thought to arise from the dorsal root ganglion. We have investigated whether this activity is resident in the cell bodies of dorsal root ganglion neurons and if it is retained in vitro. Dorsal root ganglion neurons from rats with a chronic constriction injury (CCI) from 4 loose ligatures of chromic gut sutures around the sciatic nerve were used. Isolated neurons were studied using the whole cell patch technique in current clamp mode within 6 hours of preparation. Neurons from rats with CCI showed a significantly increased incidence of spontaneous action potential activity (18/88 vs. 1/36 neurons). Firing activity consisted of both random spikes and long trains of regular, rapid spikes, with random activity being the exclusive mode in most cells. Spontaneous resting potential fluctuations (up to 10 m V peak-to-peak) occurred in both control and CCI neurons, and triggered the spontaneous, random action potentials in neurons from CCI rats. Spontaneously firing neurons exhibited more negative action potential threshold (-34.8 mV) when compared to quiescent neurons from ganglia either after CCI (-18.7 mV) or controls (-20.5 mV). These findings show that spontaneous action potential activity after CCI is a property residing in the cell bodies of dorsal root ganglion neurons and is amenable to more detailed analysis using such an in vitro system, allowing better understanding of the cellular changes underlying neuropathic pain from nerve injury.
Intravenous isosorbide dinitrate inhibits neutrophil aggregation and plasma-mediated stimulation of superoxide anion production

Abstract Polymorphonuclear neutrophils are known to be activated during myocardial ischaemia causing release of free oxygen radicals and capillary plugging by cell aggregates and therefore to exacerbate ischaemic myocardial injury. Nitric oxide has been shown to modulate neutrophil activation within the ischaemic myocardium and therefore reduce myocardial injury during ischaemia. Drugs that act as nitric oxide donors may therefore modify neutrophil activation. We evaluated the effect of intravenous treatment with isosorbide dinitrate on neutrophil aggregation and plasmamediated stimulation of neutrophil superoxide anion production in patients with ischaemic heart disease. Samples were obtained from patients before treatment and 15 and 30 min after receiving intravenous isosorbide dinitrate. Isosorbide dinitrate decreased neutrophil aggregation visualised in whole blood (25.3 ± 3.6, 19.0 ± 2.6 and 18.5 ± 2.6 per 300 cells, respectively, P P
Stability of RNA hairpin loops: A6-Cm-U6

Abstract The thermodynamics and circular dichroism of a series of A6-Cm-U6 (m = 4, 5, 6 or 8) oligoribonucleotides have been studied. These molecules form intramolecular hairpin loops at low temperatures and therefore are useful models for similar structures which occur in larger, natural RNA molecules. The stability of the helix forming the stem of these loops was found to be considerably greater than an intermolecular helix with the same length and composition. The most stable loop is m = 6. The enthalpy for initiation of the loop is unfavorable; it ranges from + 24 kcal, for m = 4 to + 21 kcal, for m = 6. The maximum in stability for the C6 loop and the large positive enthalpy for loop initiation are in disagreement with expectations from simple theories assuming a Gaussian distribution of end-to-end distances. Loop strain for m = 4 and m = 5 and the unstacking of the cytosines on loop formation are likely physical explanations for these thermodynamic data. The circular dichroism spectrum of cytosine residues in the C6 and C8 loops is very similar to the spectrum of single-stranded oligoribocytidylate. However, the cytosine residues in the C5 loop have a very different circular dichroism spectrum from the corresponding oligo(C5) spectrum. In accordance with the thermodynamic data, we conclude from the circular dichroism data that the C5 loop has an altered conformation from the C5 and C8 loops.
First report of Streptomyces stelliscabiei causing potato common scab in Michigan.

Potato (Solanum tuberosum L.) common scab can be caused by multiple Streptomyces spp., with S. scabies as a predominant species (2,3). However, according to our survey in August 2007, many symptomatic potato tubers did not have S. scabies in Michigan. To identify the pathogen, potato tubers with scab symptoms were collected from two fields in Michigan, and Streptomyces spp. were isolated using Streptomyces selective medium (STR) (2). Pure cultures of the isolates were obtained by transferring single colonies and incubation at 28°C on STR. Three isolates, designated HER21, HER24, and HER26, were identified as Streptomyces stelliscabiei based on morphological and physiological characterization (1). Bacterial cultures were prepared in liquid yeast malt extract at 28°C on an incubator shaker at 150 rpm. Genomic DNA was extracted from the cultures and used as a template for PCR with species-specific primers for Streptomyces spp. (4). The isolates gave a positive PCR reaction with primers Stel3 and T2st2 for S....
A disaster queue with Markovian arrivals and impatient customers

We consider a single server queueing system in which arrivals occur according to a Markovian arrival process. The system is subject to disastrous failures at which times all customers in the system are lost. Arrivals occurring during the time the system undergoes repair are stored in a buffer of finite capacity. These customers can become impatient after waiting a random amount of time and leave the system. However, these customers do not become impatient once the system becomes operable. When the system is operable, there is no limit on the number of customers who can be admitted. The structure of this queueing model is of GI/M/1-type that has been extensively studied by Neuts and others. The model is analyzed in steady state by exploiting the special nature of this type queueing model. A number of useful performance measures along with some illustrative examples are reported.
Localization of heme oxygenase in rat retina: effect of light adaptation

Heme oxygenase-2 isozyme is the predominant form of heme oxygenase in rat brain by western blot analysis. Heme oxygenase-1 isozyme is not induced by light adaptation in rat retina by western blot analysis. Immunocytochemistry localizes heme oxygenase-2 in three areas of the retina: the retinal pigment epithelium, inner segment and external nuclear layers of the rat retina. Ganglion cells and cell bodies of the internal nuclear layer of the retina and Muller cells were largely unstained for heme oxygenase-2. The localization of heme oxygenase-2 in the retina implies that its function is not associated with phototransduction. Also, light adaptation does not appear to induce heme oxygenase-1, a measure of oxidative injury.
Actions of phosphomonoesters on CA1 hippocampal neurons as revealed by a combined electrophysiological and nuclear magnetic resonance study.

Phosphomonoesters (PMEs), precursors of membrane phospholipids, are found in high levels in the developing brain and in Alzheimer's disease brain. The present study details the neurophysiological and metabolic effects of acute PME elevation on the Fisher 344 rat in vitro hippocampal slice. Two abundant PMEs, phosphoethanolamine (PE) and L-phosphoserine (PS), reliably altered properties of synaptic transmission at the Schaffer collateral/commissural—CA1 cell synapse. Specifically, PE reversibly depressed the amplitude of population EPSPs at millimolar concentrations but had no effect at micromolar concentrations. PS had biphasic effects on population EPSPs, inducing first a reduction followed by an enhancement of response amplitude. In contrast to PE, the effects of PS were not reversible; population EPSPs were augmented during the wash of PS, and the CA3 region generated evoked (but not spontaneous) epileptiform discharges. 31P nuclear magnetic resonance spectroscopy revealed enhanced slice uptake of PS compared to PE. There was no significant effect of PE on slice high-energy phosphates but incubation with PS significantly lowered slice phosphocreatine (PCr) and ATP concentrations. These observations indicate that the slice uptake of PS could be energy requiring and the enhanced response amplitude observed at 5 mM PS also could produce a drain on high-energy phosphates. Possible modes of PME action on hippocampal physiology are discussed.
Biological messiness vs. biological genius: Mechanistic aspects and roles of protein promiscuity.

In contrast to the traditional biological paradigms focused on ‘specificity’, recent research and theoretical efforts have focused on functional ‘promiscuity’ exhibited by proteins and enzymes in many biological settings, including enzymatic detoxication, steroid biochemistry, signal transduction and immune responses. In addition, divergent evolutionary processes are apparently facilitated by random mutations that yield promiscuous enzyme intermediates. The intermediates, in turn, provide opportunities for further evolution to optimize new functions from existing protein scaffolds. In some cases, promiscuity may simply represent the inherent plasticity of proteins resulting from their polymeric nature with distributed conformational ensembles. Enzymes or proteins that bind or metabolize noncognate substrates create ‘messiness’ or noise in the systems they contribute to. With our increasing awareness of the frequency of these promiscuous behaviors it becomes interesting and important to understand the molecular bases for promiscuous behavior and to distinguish between evolutionarily selected promiscuity and evolutionarily tolerated messiness. This review provides an overview of current understanding of these aspects of protein biochemistry and enzymology.
Mechanisms of Disease: congenital muscular dystrophies—glycosylation takes center stage

The dystroglycanopathies are a group of muscular dystrophies that are caused by glycosylation defects in α-dystroglycan, an important membrane protein that binds to the extracellular matrix. In this review, Paul Martin summarizes the genetic and clinical features of these disorders, and discusses the possible roles of dystroglycanopathy-associated genes in α-dystroglycan glycosylation. Recent studies have defined a group of muscular dystrophies, now termed the dystroglycanopathies, as novel disorders of glycosylation. These conditions include Walker–Warburg syndrome, muscle–eye–brain disease, Fukuyama-type congenital muscular dystrophy, congenital muscular dystrophy types 1C and 1D, and limb-girdle muscular dystrophy type 2I. Although clinical findings can be highly variable, dystroglycanopathies are all characterized by cortical malformations and ocular defects at the more severe end of the clinical spectrum, in addition to muscular dystrophy. All of these disorders are defined by the underglycosylation of α-dystroglycan. Defective glycosylation of dystroglycan severs the link between this important cell adhesion molecule and the extracellular matrix, thereby contributing to cellular pathology. Recent experiments indicate that glycosylation might not only define forms of muscular dystrophy but also provide an avenue to the development of therapies for these disorders.
Island biogeographical theory: Can it be used to predict lotic recovery rates?

Classic island biogeographic theory predicts that equilibrium will be reached when immigration and extinction rates are equal. These rates are modified by number of species in source area, number of intermediate islands, distance to recipient island, and size of intermediate islands. This general model has been variously modified and proposed to be a stochastic process with minimal competitive interaction or heavily deterministic. Predictive models of recovery (regardless of the end point chosen) have been based on the appropriateness of the MacArthur-Wilson models. Because disturbance frequency, severity, and intensity vary in their effect on community dynamics, we propose that disturbance levels should first be defined before evaluating the applicability of island biogeographical theory. Thus, we suggest a classification system of four disturbance levels based on recovery patterns by primary and secondary succession and faunal organization by primary (invasion of vacant areas) and secondary (remnant of previous community remains) processes. Level 1A disturbances completely destroy communities with no upstream or downstream sources of colonizers, while some component of near surface interstitial or hyporheic flora and fauna survive level 1B disturbances. Recovery has been reported to take from five years to longer than 25 years, when most invading colonists do not have an aerial form. Level 2 disturbances destroy the communities but leave upstream and downstream colonization sources (level 2A) and, sometimes, a hyporheic pool of colonizers (level 2B). Recovery studies have indicated primary succession and faunal structuring patterns (2A) with recovery times of 90–400 days or secondary succession and faunal structuring patterns (2B) with recovery times of 40–250 days. Level 3 disturbances result in reduction in species abundance and diversity along a stream reach; level 4 disturbances result in reduction of abundance and diversity in discrete patches. Both disturbance types lead to secondary succession and secondary faunal organization. Recovery rates can be quite rapid, varying from less than 10 days to 100 or more days. We suggest that island biogeographical models seem appropriate to recovery by secondary processes after level 3 and 4 disturbances, where competition may be an important organizing factor, while models of numerical abundance and resource tracking are probably of better use where community development is by primary succession (levels 1 and 2). Development of predictive recovery models requires research that addresses a number of fundamental questions. These include the role of hydrologic patterns on colonization dynamics, the role of nonaerial colonizers in recovery from level 1 disturbances, and assessment of the impact of changes in the order of invasion by colonizers of varying energetic efficiencies. Finally, we must be able to assemble these data and determine whether information that guides community organization at one level of disturbance can provide insights into colonization dynamics at other levels.
Toxicity and antiviral activity of LY253963 against respiratory syncytial and parainfluenza type 3 viruses in tissue culture and in cotton rats.

Abstract LY253963, the sodium salt of 1,3,4-thiadiazol-2-ylcyanamide, was evaluated in tissue culture and in cotton rats for toxicity and antiviral efficacy against respiratory syncytial (RSV) and parainfluenza type 3 (PIV3) viruses. The selective index (ratio of the median toxic dose: median efficacious dose) of LY253963 in HEp2 tissue culture cells was >100 against both RSV and PIV3. When given intraperitoneally to cotton rats, the minimum protective dose of LY253963 against both of these viruses was between 1 and 3 mg/kg/day. In contrast, doses of LY253963 as high as 30 mg/kg/day, administered orally after experimental inoculation of virus, did not significantly reduce pulmonary virus titers in treated animals compared to control animals given placebo. No toxic effects were noted in cotton rats, even in those given 20 mg/kg/day for eight consecutive days.
Pattern-aware file reorganization in MPI-IO

Scientific computing is becoming more data-intensive; however I/O throughput is not growing at the same rate. MPI-IO and parallel file systems are expected to help bridge the gap by increasing data access parallelism. Compared to traditional I/O systems, some factors are more important in parallel I/O system in order to achieve better performance, such as the number of requests and contiguousness of accesses. The variation of these factors can lead to significant differences in performance. Programmers usually arrange data in a logical fashion for ease of programming and data manipulation; however, this may not be ideal for parallel I/O systems. Without taking into account the organization of file and behavior of the I/O system, the performance may be badly degraded. In this paper, a novel method of reorganizing files in I/O middleware level is proposed, which takes into account the access patterns. By placing data in a way favoring the parallel I/O system, gains of up to two orders of magnitudes in reading and up to one order of magnitude in writing were observed with spinning disks and solid-state disks.
Antisense inhibition of Chk2/hCds1 expression attenuates DNA damage-induced S and G2 checkpoints and enhances apoptotic activity in HEK-293 cells

The cellular response to DNA damage involves checkpoint controls that delay cell cycle progression in order to provide time for repair of damaged DNA. Chk2/hCds1 is a recently identified homolog of the yeast Cds1 kinase that is involved in cell cycle checkpoint response to DNA damage. To investigate the functions of Chk2/hCds1 in response to DNA damage in mammalian cells, we established a stable human kidney embryonic cell line (HEK-293) that expresses antisense Chk2/hCds1 (Chk2AS) under the control of an inducible promoter. Cells that express Chk2AS display defective S-phase delay in response to DNA replication-mediated DNA damage induced by the topoisomerase I inhibitor camptothecin. The defective G2 checkpoint was also observed in Chk2AS cells exposed to the DNA damaging agent VP-16 or γ-radiation. Enhanced apoptosis was observed in Chk2AS cells after exposure to γ-radiation or camptothecin. No p53 activation was observed after DNA damage in HEK-293 or Chk2AS cells. Our results indicate that perturbation of Chk2/hCds1 expression adversely affects the S- and G2-phase checkpoints following DNA damage or DNA replication block, and suggest that reduced expression of Chk2/hCds1 might promote a p53-independent apoptotic response.
Immunohistologic identification of phenotypic antigens associated with Hodgkin and Reed-Sternberg cells. A paraffin section study.

A combination of two monoclonal antibodies, designated LN-1 and LN-2, were used in an attempt to identify the corresponding antigens in Hodgkin and Reed-Sternberg cells. The LN-1 antibody has been shown in previous studies in our laboratories to identify follicular center cells, whereas LN-2 marks certain B-cell subpopulations as well as interfollicular histiocytes. Utilizing the perioxidase-antiperioxidase (PAP) technique, paraffin-embedded sections were examined representing 39 cases of various histologic subgroups of Hodgkin's lymphoma following immunostaining with LN-1, LN-2, and the antibody to S-100. Of these 39 cases, the LN-2 antibody was found to consistently mark the majority of Hodgkin and Reed-Sternberg cells. LN-1 was found to identify Hodgkin and Reed-Sternberg cells in a smaller number of cases. In no instance were Hodgkin or Reed-Sternberg cells found to mark for the S-100 protein. The use of LN-1 and LN-2 antibodies facilitated the identification of Hodgkin and Reed-Sternberg cells and produced additional information regarding the phentotypic nature of these cells.
Radiopharmaceutical considerations for using Tc-99m MAA in lung transplant patients.

Abstract Objectives To elucidate radiopharmaceutical considerations for using technetium Tc-99m albumin aggregated (Tc-99m MAA) in lung transplant patients and to establish an appropriate routine dose and preparation procedure. Setting Tertiary care academic hospital during May 2007 to May 2009. Practice description Nuclear pharmacist working in nuclear medicine department. Practice innovation Radiopharmaceutical considerations deemed important for the use of Tc-99m MAA in lung transplant patients included radioactivity dose, particulate dose, rate of the radiolabeling reaction (preparation time), and final radiochemical purity. Evaluation of our initial 12-month experience, published literature, and professional practice guidelines provided the basis for establishing an appropriate dose and preparation procedure of Tc-99m MAA for use in lung transplant patients. Main outcome measures Radiochemical purity at typical incubation times and image quality in subsequent lung transplant patients imaged during the next 12 months. Results Based on considerations of radioactivity dose, particulate dose, rate of the radiolabeling reaction (preparation time), and final radiochemical purity, a routine dose consisting of 3mCi (111 MBq) and 100,000 particles of Tc-99m MAA for planar perfusion lung imaging of adult lung transplant patients was established as reasonable and appropriate. MAA kits were prepared with a more reasonable amount of Tc-99m and yielded high radiochemical purity values in typical incubation times. Images have continued to be of high diagnostic quality. Conclusion Tc-99m MAA used for lung transplant imaging can be readily prepared with high radiochemical purity to provide a dose of 3mCi (111 GBq)/100,000 particles, which provides images of high diagnostic quality.
Anisotropy studies of tRNA-T box antiterminator RNA complex in the presence of 1,4-disubstituted 1,2,3-triazoles.

Abstract The binding of tRNA to the T box antiterminator RNA element is a critical component of the T box riboswitch mechanism that regulates essential genes in many Gram-positive bacteria. A series of 1,4-disubstituted 1,2,3-triazoles was screened for disruption of the tRNA-T box antiterminator RNA interaction using a fluorescence anisotropy-based assay. Several compounds reduced the anisotropy greater than 50% likely indicating significant competition for binding antiterminator RNA. General structure–activity trends indicated that the substituents at both N-1 and C-4 likely are involved in ligand binding. In addition, the anisotropy of the complex was significantly decreased not only by ligands with the possibility for electrostatic interactions with the RNA, but also by ligands with the potential for π–π stacking or other hydrophobic interactions indicating that these non-electrostatic interactions could possibly be utilized in the future development of compounds that target and disrupt the function of this medicinally important riboswitch.
Ion beam properties after mass filtering with a linear radiofrequency quadrupole

The properties of ion beams passing through a linear radiofrequency quadrupole mass filter were investigated with special attention to their dependence on the mass resolving power. Experimentally, an increase of the transverse emittance was observed as the mass-to-charge selectivity of the mass filter was raised. The experimental behavior was confirmed by beam transport simulations.
Measurement and analysis of sound levels from a RASS site near Barrow, Alaska

Abstract Measurements of sound levels from an acoustic source for a RASS (Radio Acoustic Sounding System) system have been analyzed in support of the environmental assessment and permitting for an ARM (Atmospheric Radiation Measurement) site near Barrow, Alaska. Background sound levels and noise levels at two frequencies have been measured as a function of distance from the source. The Fast Field Program (FFP) is used to extrapolate the data for cases where the sound levels are significant at the maximum measurement range. The FFP is also used to investigate the effect of wind direction for three of the highest level days.
How do I remember? Let me count the ways.

In this issue, Diekelmann, Wilhelm and Born1 provide an extensive and critical review of the rapidly growing literature on sleep-dependent memory consolidation. But rather than simply reviewing this literature, they have taken this opportunity to ask several important questions concerning off-line memory processing. Most gratifying is their decision not to simply look ever more deeply into frequently discussed questions, but rather to raise several new ones. They ask what kinds of memories are consolidated by sleep, what kinds of consolidation are accomplished, and what kinds of sleep are required. For the reader looking for a quick set of answer, they won't find them here or in the Diekelmann article. But the authors have done a superb job of organize the literature to support a series of proposed answers, and I will offer a few more, all of which will hopefully serve as a basis for further investigations. The task of sorting out the interactions between sleep and memory is a daunting one. We summarized some of these issues in an earlier review.2 At the very least (Fig 1), one has to address the question of how five stages of sleep3 interact with at least six types of memories4 and six stages of post-encoding memory processing,2 for a combined total of 144 distinct sub-questions (e.g., how does REM sleep affect the stabilization of classical conditioning; Fig 1). But Diekelmann and colleagues have now added another layer of more subtle questions – how do the strength of initial encoding and the perceived value of the memory interact with these sleep-dependent processes, how do the amount of sleep and the timing of the sleep affect them, and how do these processes change with age and in the presence of psychiatric disorders? Open in a separate window Figure 1 The sleep cycle, memory systems, and memory stages (A) The human sleep cycle—across the night, NREM and REM sleep cycle every 90 min in an ultradian manner, while the ratio of NREM to REM sleep shifts. During the first half of the night, stages 3 and 4 NREM (SWS) dominate, while stage 2 NREM and REM sleep prevail in the latter half of the night. EEG patterns also differ significantly between sleep stages, with electrical oscillations such as K complexes and sleep spindles occurring during stage 2 NREM, slow (0.5–4Hz) delta waves developing in SWS, and theta waves seen during REM. (B) Memory systems—human memory is most commonly divided into declarative forms, with further subdivisions into episodic and semantic; and nondeclarative forms, subdivided into an array of different types including procedural skill memory (C) Developing stages of memory—following the initial encoding of a memory, several ensuing stages are proposed, beginning with consolidation, as well as integration of the memory representation, translocation of the representation, or erasure of the memory. Also, following later recall, the memory representation is believed to become unstable once again, requiring periods of reconsolidation. Reproduced from 2.
Imaging of photo-occlusion colour films for quantitative strain and stress analysis:

AbstractDigital image analysis and processing techniques have been applied to colour films obtained by a photo-occlusion method to quantitatively describe strain and stress distributions. The objective here is to outline the different colour areas (training areas) on each image accurately and consistently in order for a quantitative comparison of the induced stress on each film to be made based on the size of each colour area. To ensure that the outlined colour areas are uniform in terms of grey levels (isochromatic areas), a statistical analysis was pursued. To ensure consistency of the outline process on each image, an autocorrelation distance was used. The technique described allows direct quantitative judgement of strain fields obtained ‘before’ and ‘after’ treatment.The technique can be applied in any research area where a sequence of isochromatic areas can be recorded on a photographic film.
Directional phase instability on a cubic compressible lattice near a second-order phase transition with a three-component order parameter

We have examined the question of whether a second-order phase transition can occur in a normal manner for a n = 3 component order parameter on a compressible cubic lattice, for which the perovskites are an example. For the general third-order strain coupling, the strain-mediated quartic interactions of the order parameter are found to be controlled by three exponents ..cap alpha../sub I/, ..cap alpha../sub 2//sub I/, and ..cap alpha..'/sub 2//sub I/ obtained on the incompressible lattice. Since the specific-heat exponent ..cap alpha../sub I/ <0 for n = 3 in d = 3 dimensions, the component of the strain-mediated interactions controlled by ..cap alpha../sub I/ does not have the microscopic directional instability discussed by Bergman and Halperin and by de Moura, Lubensky, Imry, and Aharony for the Ising model on an elastically nonisotropic lattice. The expansion in epsilon = 4 - d to O (epsilon/sup 2/) indicates that ..cap alpha../sub 2//sub I/ and ..cap alpha..'/sub 2//sub I/ are positive at d = 3. The twenty components of the interaction controlled basically by ..cap alpha../sub 2//sub I/ or ..cap alpha..'/sub 2//sub I/ will thus exhibit the instability and, contrary to the conjecture of de Moura et al., will prevent the cubic ormore » Heisenberg fixed points or the fourteen possible Fisher-renormalized versions thereof from being reached. Stability is not restored if the host lattice is taken to be elastically isotropic but is restored if the strain couples only to the scalar product of order-parameter fields. Otherwise, it appears that the n = 3 compressible cubic phase transition cannot be simply second order.« less
Role of support-nanoalloy interactions in the atomic-scale structural and chemical ordering for tuning catalytic sites.

The understanding of the atomic-scale structural and chemical ordering in supported nanosized alloy particles is fundamental for achieving active catalysts by design. This report shows how such knowledge can be obtained by a combination of techniques including X-ray photoelectron spectroscopy and synchrotron radiation based X-ray fine structure absorption spectroscopy and high-energy X-ray diffraction coupled to atomic pair distribution function analysis, and how the support-nanoalloy interaction influences the catalytic activity of ternary nanoalloy (platinum–nickel–cobalt) particles on three different supports: carbon, silica, and titania. The reaction of carbon monoxide with oxygen is employed as a probe to the catalytic activity. The thermochemical processing of this ternary composition, in combination with the different support materials, is demonstrated to be capable of fine-tuning the catalytic activity and stability. The support-nanoalloy interaction is shown to influence structural and chemical o...
First-principles study of ternary fcc solution phases from special quasirandom structures

In the present work, ternary special quasirandom structures (SQSs) for a fcc solid solution phase are generated at different compositions, xA=xB=xC=(1/3) and xA=(1/2), xB=xC=(1/4), whose correlation functions are satisfactorily close to those of a random fcc solution. The generated SQSs are used to calculate the mixing enthalpy of the fcc phase in the Ca-Sr-Yb system. It is observed that first-principles calculations of all the binary and ternary SQSs in the Ca-Sr-Yb system exhibit very small local relaxation. It is concluded that the fcc ternary SQSs can provide valuable information about the mixing behavior of the fcc ternary solid solution phase. The SQSs presented in this work can be widely used to study the behavior of ternary fcc solid solutions.