cssi/SciSciGPT-SciSciNet huggingface dataset:
The influence of age on the toxicity and metabolism of methyl parathion and parathion in male and female rats.

Abstract To determine the mechanisms responsible for the variations in toxicity of methyl parathion and parathion, the in vitro metabolism of these insecticides and cholinesterase sensitivity to their respective oxygen analogs methyl paraoxon and paraoxon were studied in male and female rats of several ages. For rats of five ages studied (1, 12–13, 23–24, 35–40, and 56–63 days), there was a gradual decrease in susceptibility to poisoning by both insecticides with increasing age up to 35–40 days for both sexes. Age differences in susceptibility were not related to differences in sensitivity of cholinesterase to inhibition by paraoxon or methyl paraoxon in vitro. Oxidative formation of the oxygen analogs, oxidative aryl cleavage, and glutathione-dependent dealkylation and dearylation of methyl parathion and parathion were assayed in liver homogenates of male and female rats of the five ages. Rates of enzymatic detoxification of their corresponding oxygen analogs by A-esterase, glutathione- S -aryl-, and - S -alkyl-transferase and inactivation by binding were also investigated. Correlation coefficients for rates of metabolism versus LD50 values for the different ages were calculated. In general, changes in LD50 values with age for methyl parathion and parathion correlated better with changes in rates of reactions which represented detoxification pathways for methyl paraoxon and paraoxon than for reactions which represented direct metabolism of the parent insecticides. Both male and female rats became much less sensitive to the acute lethal effects of methyl paraoxon and paraoxon with increasing age. This is consistent with a hypothesis that changes in LD50 values of methyl parathion and parathion with age are due to changes in rates of metabolism of the oxygen analogs.
Clearance of infused triglyceride by resting horses.

Abstract 1. 1. Clearance of infused lipid was observed in six mature resting horses, 2 to 6 hr after receiving a meal of alfalfa hay. 2. 2. Intralipid®, a 10% triglyceride emulsion, was infused at a rate of 0.2 ml/kg into the jugular vein. 3. 3. Blood samples were obtained for 80min post-infusion and assayed for plasma triglyceride concentration. 4. 4. Clearance rate of the infused lipid was very slow (mean t 1 2 = 269 min). 5. 5. The clearance rate of the infused lipid in these horses was much slower than has been observed in other species. 6. 6. The slow clearance of infused triglyceride in horses may suggest an inability to efficiently metabolize lipoproteins.
ORGANIC CARBON RELEASE BY DUNALIELLA SALINA (CHLOROPHYTA) UNDER DIFFERENT GROWTH CONDITIONS OF CO2, NITROGEN, AND SALINITY1

Two strains of Dunaliella salina (Dunal) Teod., UTEX 1644 and UTEX 200, were cultured under different growth regimes, including 10 mM NO3− or NH4+, 1.5 or 3.0 M NaCl, and low (0.035%) or high (5%) CO2 in air. The release of 14C-labeled dissolved organic carbon (DOC), expressed as a rate and as a percentage of photosynthetic 14CO2 assimilation, was subsequently determined. The percentage of DOC released was inversely related to cell density in the assay medium, but photosynthesis on a per-cell basis was not. Release of DOC was low, in the range of 1–5% of photosynthesis, but during acclimation to growth on NH4+, it rose to 11%. The presence of NH4+ rather than NO3− in the growth medium increased the rate of release by both strains, but the percentage release was stimulated only in UTEX 200 cells, because their photosynthetic rate was depressed by NH4+. For UTEX 1644, high, as compared to low, CO2-grown cells, had somewhat higher rates and percentages of DOC release, but release from UTEX 200 cells was unaffected by the growth-CO2. The rate of DOC release by high CO2-grown cells was not enhanced at a low concentration of dissolved inorganic carbon, indicating that the released material did not originate from the photorespiratory pathway. The effects of NaCl on DOC release varied with strain and growth conditions. For UTEX 200, the cells in NO3−, but not NH4+, exhibited a doubling or more in percentage of release with a doubling in NaCl concentration, irrespective of growth-CO2. With UTEX 1644 the low CO2-grown cells showed the greatest enhancement in 3.0 M NaCl. Organic matter accumulated on the external surface of the cell membrane and constituted a well-defined cell-coat, which was more dense in NH4+ than in NO3−-grown cells. Microtubules, which may play a role in maintaining cell shape, were observed just below the plasma membrane. From a practical viewpoint, the presence of organic material in the hypersaline ponds of salt-works is detrimental to salt production. When D. salina cells become abundant in such ponds, the attendant, continuous release of DOC may make a significant contribution to the problem.
Us food and drug administration survey of cadmium, lead and other elements in clams and oysters

In Fiscal Years 1985/1986, the US Food and Drug Administration conducted a survey of cadmium, lead and other elements in fresh clams and oysters collected from US coastal areas in use for shellfish production. Shellfish were analysed for cadmium and lead by using a dry ash-anodic stripping voltammetric method. Other elements (aluminium, arsenic, beryllium, calcium, chromium, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, phosphorus, potassium, selenium, sodium, strontium, vanadium and zinc) were determined by using inductively coupled plasma-atomic emission spectrometry, direct current plasma-atomic emission spectrometry or hydride generation atomic absorption spectrometry. A total of 75 hardshell clam, 59 softshell clam, 104 Eastern oyster and 40 Pacific oyster samples were analysed for cadmium and lead. Average levels found were 0.09, 0.05, 0.51 and 1.1 mg/kg wet weight for cadmium and 0.24, 0.30, 0.11 and 0.06 mg/kg wet weight for lead in hardshell clams, softshell clams, Eastern oysters and Pacific oysters, respectively. The other 19 elements were determined in 10-104 samples of the four types of shellfish. These data provide baseline values for elements in clams and oysters harvested from US coastal waters.
In vitro growth of glial cell-enriched and depleted populations from mouse cerebellum.

Summary Glial cell-enriched and -depleted populations isolated from 10-day-old mouse cerebella have been grown in vitro. There are marked differences in the cellular morphology between these two populations. The glial cell-enriched populations are very heterogeneous with respect to cell size, morphology and processes, whereas the glial cell-depleted populations are very homogeneous, containing a cell type with a small cell body and predominantly bipolar processes. Further characterization of the cell types has been effected using antiserum prepared against GFA protein and tubulin. The immunocytochemical localization of these proteins clearly identifies astrocytes and neurons. The glial cell enriched populations contain several types of astrocytes and neurons in addition to cells of nonectodermal origin, whereas the glial cell-depleted populations contain predominantly a single neuronal cell type, the granule cells.
Dual-Aircraft Investigation of the inner Core of Hurricane Norbert. Part III: Water Budget

Abstract The hydrometeor water budget of Hurricane Norbert on 24 September 1984 is computed using two micro- physical retrieval techniques. Three-dimensional distributions of condensation, evaporation, precipitation, and advection of cloud and precipitation are computed, and a bulk water budget is computed as the volume integral of these distributions. The role of the microphysical retrievals is to provide the three-dimensional distribution of cloud water content, since it cannot be determined with the equipment available. Both retrieval methods use the steady-state continuity equation for water. The first method determines precipitation formation mechanisms from the radar-reflectivity and Doppler wind fields. The cloud water content is determined, through microphysical modeling, to be the amount necessary to explain the rate of precipitation formation. The second method (that of Hauser el al.) solves the water continuity equations as a boundary value problem, while also employing microphysical modeling. ...
Deciphering the Regulatory Circuitry That Controls Reversible Lysine Acetylation in Salmonella enterica

In Salmonella enterica, the reversible lysine acetylation (RLA) system is comprised of the protein acetyltransferase (Pat) and sirtuin deacetylase (CobB). RLA controls the activities of many proteins, including the acetyl coenzyme A (acetyl-CoA) synthetase (Acs), by modulating the degree of Acs acetylation. We report that IolR, a myo-inositol catabolism repressor, activates the expression of genes encoding components of the RLA system. In vitro evidence shows that the IolR protein directly regulates patexpression. AniolRmutant strain displayed a growth defect in minimal medium containing 10 mM acetate, a condition un- der which RLA function is critical to control Acs activity. Increased levels of Pat, CobB, or Acs activity reversed the growth de- fect, suggesting the Pat/CobB ratio in an iolRstrain is altered and that such a change affects the level of acetylated, inactive Acs. Results of quantitative reverse transcription-PCR (qRT-PCR) analyses of pat,cobB, andacsexpression indicated that expression of the genes alluded to in the IolR-deficient strain was reduced 5-, 3-, and 2.6-fold, respectively, relative to the levels present in the strain carrying the iolRallele. Acs activity in cell-free extracts from an iolRmutant strain was reduced ~25% relative to that of theiolRstrain. Glucose differentially regulated expression of pat,cobB, andacs. The catabolite repressor protein (Crp) posi- tively regulated expression of patwhile having no effect oncobB. IMPORTANCE Reversible lysine acylation is used by cells of all domains of life to modulate the function of proteins involved in diverse cellular processes. Work reported herein begins to outline the regulatory circuitry that integrates the expression of genes encoding enzymes that control the activity of a central metabolic enzyme in C2 metabolism. Genetic analyses revealed effects on reversible lysine acylation that greatly impacted the growth behavior of the cell. This work provides thefirst insights into the complexities of the system responsible for controlling reversible lysine acylation at the transcriptional level in the enteropatho- genic bacterium Salmonella enterica.
Alternative Approaches to Research in Physical Therapy: Positivism and Phenomenology

This article presents philosophical approaches to research in physical therapy. A comparison is made to demonstrate how the research purpose, research design, research methods, and research data differ when one approaches research from the philosophical perspective of positivism (predominantly quantitative) as compared with the philosophical perspective of phenomenology (predominantly qualitative). Differences between the two approaches are highlighted by examples from research articles published in Physical Therapy . The authors urge physical therapy researchers to become familiar with the tenets, rigor, and knowledge gained from the use of both approaches in order to increase their options in conducting research relevant to the practice of physical therapy.
Rupture Propagation and Ground Motion of Strike‐Slip Stepovers with Intermediate Fault Segments

Field studies of historic rupture traces show that fault stepovers commonly serve as endpoints to earthquake ruptures. This is an effect that is corroborated by past dynamic modeling studies. However, field studies also show a great deal of complexity in fault‐zone structure within a stepover, which is often simplified out of modeling studies. In the present study, we use the 3D finite‐element method to investigate the effect of one type of smaller‐scale complexity on the rupture process: a smaller fault segment positioned between the two primary strands of a strike‐slip fault stepover. We find that such small faults can have a controlling effect on whether or not a rupture is able to jump the stepover and on the resulting ground motions from these ruptures. However, this effect is neither straightforward nor linear: the length of the intermediate segment and its basal depth, as well as whether the stepover is extensional or compressional, all contribute to the rupture behavior and ground‐motion distribution. These results have important implications for assessing the probability of a rupture propagating through small‐ and large‐scale discontinuities in faults, as well as for evaluating ground‐motion intensities near fault stepovers. Because of the sensitivity of results to so many parameters, these results also suggest that modeling studies on idealized fault geometries may not be sufficient to describe the rupture behaviors of specific complex fault systems. Site‐specific modeling studies, where possible, will provide better inputs and constraints for probabilistic rupture length assessments as well as for ground‐motion estimates.
A directed graph formulation of the multistage distribution expansion problem

In this paper, the objectives and detailed analysis of the multistage distribution expansion are presented. The problem is modeled as a directed graph minimum edge cost network flow problem. This new formulation details a multistage framework within a single mathematical program while addressing several deficiencies of previous approaches. The accuracy of a single step approximation of the objective function, without using the conventional linearization techniques, is discussed. Each of the constraints is introduced in terms of industry standard practices. Detailed numerical results for practical study cases are provided in a separate paper.
Oxidative Dissolution Potential of Biogenic and Abiogenic TcO2 in Subsurface Sediments

Technetium-99 (Tc) is an important fission product contaminant associated with sites of nuclear fuels reprocessing and geologic nuclear waste disposal. Tc is highly mobile in its most oxidized state [Tc(VII)O{sub 4}{sup -}] and less mobile in the reduced form [Tc(IV)O{sub 2} {center_dot} nH{sub 2}O]. Here we investigate the potential for oxidation of Tc(IV) that was heterogeneously reduced by reaction with biogenic Fe(II) in two sediments differing in mineralogy and aggregation state; unconsolidated Pliocene-age fluvial sediment from the upper Ringold (RG) Formation at the Hanford Site and a clay-rich saprolite from the Field Research Center (FRC) background site on the Oak Ridge Site. Both sediments contained Fe(III) and Mn(III/IV) as redox active phases, but FRC also contained mass-dominant Fe-phyllosilicates of different types. Shewanella putrefaciens CN32 reduced Mn(III/IV) oxides and generated Fe(II) that was reactive with Tc(VII) in heat-killed, bioreduced sediment. After bioreduction and heat-killing, biogenic Fe(II) in the FRC exceeded that in RG by a factor of two. More rapid reduction rates were observed in the RG that had lower biogenic Fe(II), and less particle aggregation. EXAFS measurements indicated that the primary reduction product was a TcO{sub 2}-like phase in both sediments. The biogenic redox product Tc(IV) oxidized rapidly and completelymore » in RG when contacted with air. Oxidation, in contrast, was slow and incomplete in the FRC, in spite of similar molecular scale speciation of Tc compared to RG. X-ray microprobe, electron microprobe, X-ray absorption spectroscopy, and micro X-ray diffraction were applied to the whole sediment and isolated Tc-containing particles. These analyses revealed that non-oxidizable Tc(IV) in the FRC existed as complexes with octahedral Fe(III) within intra-grain domains of 50-100 {micro}m-sized, Fe-containing micas presumptively identified as celadonite. The markedly slower oxidation rates in FRC as compared to RG were attributed to mass-transfer-limited migration of O{sub 2} into intra-aggregate and intraparticle domains where Tc(IV) existed; and the formation of unique, oxidation-resistant, intragrain Tc(IV)-Fe(III) molecular species.« less
Video steganalysis using spatial and temporal redundancies

In this paper we present a novel video steganalysis method using neural networks and support vector machines to detect video steganograms with very limited a-prior knowledge about the steganogram embedding method.
Validity of assessments for English Language Learning students in a national/international context

This paper provides a summary of research that shows a substantial performance gap between native and non-native speakers of assessment language. Such a performance gap increases with the level of language demand of the test items. Results of studies indicate that unnecessary linguistic complexity may impact reliability and validity of the assessment outcomes. To control for language factors as a source of bias, this paper introduces the concept of linguistic modification of assessment through which unnecessary linguistic complexity of test items is reduced or eliminated. The paper recommends that test developers be aware of the impact of linguistic complexity in assessment and should plan to control for such possible source of bias.
Depression in Medicaid-covered youth: differences by race and ethnicity.

Background Racial disparities have previously been noted in antidepressant use among Medicaid-covered youth. Objective To determine if racial and ethnic differences are due to dissimilarity in the prevalence of diagnosed depression or disparate treatment patterns. Methods Claims were examined for 192 441 youth (5-18 years old) who had been continuously enrolled in Medicaid from July 1, 1997, to December 31, 1998. Diagnosed depression was defined as having been assigned anInternational Classification of Diseases, Ninth Revisioncode for a depressive disorder in a medical claim. Logistic regression methods were used to evaluate the association between race/ethnicity and (1) depression diagnosis and (2) depression treatment in the 6 months following a new episode of diagnosed depression. All analyses were controlled for age, sex, and rural or urban residence. Results Two percent of the total sample had a depression diagnosis, 25% of which were new episodes of depression. Compared with white youth, Hispanic (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.46-0.57), Asian/Pacific Islander (OR, 0.16; 95% CI, 0.12-0.21), and black (OR, 0.31; 95% CI, 0.26-0.37) youth were less likely to have a depression diagnosis. Following a new diagnosis, Native American (OR, 0.29; 95% CI, 0.18-0.46) and Hispanic (OR, 0.42; 95% CI, 0.30-0.61) youth were less likely than white youth to have received an antidepressant or a mental health specialty visit. Conclusions Racial and ethnic disparities exist in both the prevalence and treatment of diagnosed depression. Future studies should examine underlying reasons for these disparities and how they affect the quality of care for depressed Medicaid-covered youth.
The Mechanical Properties of E. coli Type 1 Pili Measured by Atomic Force Microscopy Techniques

The first step in the encounter between a host and a pathogen is attachment to the host epithelium. For uropathogenic Escherichia coli, these interactions are mediated by type 1 and P adhesive pili, which are long (approximately 1 microm) rods composed of more than 1000 protein subunits arranged in a helical structure. Here we used single-molecule atomic force microscopy to study the mechanical properties of type 1 pili. We found that type 1 pili readily extend under an applied force and that this extensibility is the result of unwinding the pilus rod's helical quaternary structure. The forced unraveling is also reversible, with helical rewinding taking place under considerable forces (approximately 60 pN). These data are similar to those obtained on P pili using optical tweezers, indicating that these are conserved properties of uropathogenic E. coli pili. We also show that our data can readily be reproduced using Monte Carlo simulation techniques based on a two-state kinetic model. This model provides a simple way to extrapolate the mechanical behavior of pili under a wide range of forces. We propose that type 1 pilus unraveling is an essential mechanism for absorbing physiological shear forces encountered during urinary tract infections and probably essential for adhesion and colonization of the bladder epithelium.
Epidemiology and Child Psychiatry: Introduction

Most of the contributions to this special section were first presented at an Institute on Epidemiology and Child Psychiatry that was held at the 26th Annual Meeting of the American Academy of Child Psychiatry in Atlanta, Georgia. The papers have been revised and expanded for written presentation, and additional contributions have been solicited and included. Epidemiology is the study of the distribution of disease in the population. Knowledge about the way that diseases are distributed can be used for a number of purposes. These include the planning of services, the prevention of disease, and understanding the causes and the classification of disease. The contributions in the special section have been chosen to illustrate each of these uses. Epidemiologists use a number of concepts and special terms to describe the occurrence and distribution of disease. These are defined and illustrated in the paper by Zena Stein and Mervyn Susser, which serves as a technical introduction for the epidemiological novice. Basic concepts such as incidence and prevalence are defined, and the process of population screening is described. The properties of screening instruments including their sensitivity and specificity arc defined. Stein and Susser also describe the differences between cohort and case-control studies, and in the process illustrate the range of areas in which the epidemiological method can be applied.
Murray et al., Music Education in the Middle Ages and the Renaissance

The essays collected in Music Education in the Middle Ages and the Renaissance show a wide diversity of approaches to musical pedagogy, which they illuminate in new and often suggestive ways; they make a significant contribution to the history of music pedagogy and will amply repay careful study. Collectively, the essays address five questions. What pedagogical methods were used? What did students learn? Who were the teachers, and who the students? Where and when was music learned? Why was music learned? Readers led by the book’s title to assume that the Middle Ages and the Renaissance will receive equal treatment may be disappointed: only three of the book's seventeen essays are devoted to medieval topics. “Early Modern” would have served the later period more appropriately than “Renaissance,” as publications addressed include those as late as Mace (1676) and Playford (1683). A comprehensive bibliography would have been a service to readers.
Advancing Public Health and Medical Preparedness with Operations Research

Planning for a catastrophe involving a disease outbreak with the potential for mass casualties is a significant challenge for emergency managers. Public health experts at the US Centers for Disease Control and Prevention CDC teamed with operations researchers to address important aspects of mass dispensing: medical supply distribution, locations of dispensing facilities, optimal facility staffing and resource allocation, routing of the population, and dispensing methods. Simulation-optimization technology was integrated into a decision support and data management suite, RealOpt©, for tactical and strategic operational planning. RealOpt has enabled the CDC to provide modern tools that support dynamic planning for emergencies and that establish a knowledge data bank to provide feedback about the deployment of various techniques. The RealOpt suite now has a US user base of over 6,500 public health and emergency directors covering all states, plus many international users. RealOpt has been applied in hundreds of drills and dispensing events, including anthrax preparedness, and for seasonal flu and H1N1 vaccination events.
Influence of antimony catalysts with hydroxyethoxy ligands on polyester polymerization

The effectiveness of antimony polymerization catalysts for polyester, with varying numbers of hydroxyethoxy ligands on antimony, was studied. The ligand number, ranked in decreasing effectiveness was 5 = 3 > 2 > 1 ≫ 0. Results for this series of compounds are consistent with a mechanism in which antimony bonds with polyester chain ends to catalyze intermolecular condensation.
Inpatient Surgical Bowel Preps: Making Them Work

This article will describe the evidence-based approach our hospital developed to best prepare children for abdominal surgery. Our evidence-based interdisciplinary approach was based on the work of [McCallin, A. (2001). Interdisciplinary practice—A matter of teamwork: An integrated literature review. Journal of Clinical Nursing, 10, 419–428], [Melnyk, B. M. (2002). Evidence-based practice. Strategies for overcoming barriers in implementing evidence-based practice. Pediatric Nursing, 28, 159–161], [Melnyk, B. M., & Fineout-Overholt, E. (2002). Evidence-based practice. Key steps in implementing evidence-based practice: Asking compelling, searchable questions and searching for the best evidence. Pediatric Nursing, 28, 262–266], [Sierchio, G. P. (2003). A multidisciplinary approach for improving outcomes. Journal of Infusion Nursing, 26, 34–43], and [Wojner, A. W. (1996). Outcomes management: An interdisciplinary search for best practice. AACN Clinical Issues, 7, 133–145]. At our hospital, a leading children's hospital in an eastern urban setting, we surgically manage children, from newborns to young adults, with a variety of diagnoses. These diagnoses include the following: inflammatory bowel diseases, such as Crohn's disease and UC, imperforate anus, necrotizing enterocolitis, and abdominal tumors. The bowel prep is an integral part of these children's surgical preparation.
Natural and experimental infections of Arcobacter in poultry

Abstract Arcobacter butzleri causes human enteritis and is frequently recovered from poultry carcasses. The purpose of this study was to determine 1) the natural distribution of A. butzleri in poultry and 2) its relative pathogenicity in experimentally infected poultry. Cloacal samples (n = 407) were collected on four occasions from three flocks of chickens. Overall, Arcobacter spp. were recovered from 15% of the birds; A. butzleri was identified in 1% of cloacal samples. Three experimental trials were conducted to determine the susceptibility of birds. In Trial 1, 3-d-old chicks (n = 62) were divided into three groups and infected per os with 1) A. butzleri American Type Culture Collection (ATCC) 49616, 2) a suspension of four field strains of A. butzleri isolated from retail purchased chicken, and 3) Campylobacter jejuni (positive control). Arcobacter was not detected in cloacal swabs or in cecal samples of chicks through Day 5 postinfection; C. jejuni was detected in cloacal swabs of all positive control birds. In Trial 2, 5-d-old outbred turkey poults (n = 88) were infected as described above with the addition of a group infected with a suspension of four field strains of A. butzleri from turkey meat. Arcobacter butzleri was recovered from either cloacal swabs or cecal contents of only 6.0% of birds (4 of 67); C. jejuni was recovered from 100% of the positive control birds (n = 21). In Trial 3, 3-d-old turkey poults of the highly inbred Beltsville White strain (n = 141) were experimentally inoculated. In contrast to earlier trials, A. butzleri was recovered overall from the cloacal swabs or tissues of 65% of the turkeys.
Serum Albumin and Prealbumin in Calorically Restricted, Nondiseased Individuals: A Systematic Review

Abstract Purpose Undernutrition is often suspected in patients when serum albumin or prealbumin levels are low. We asked whether these measures are indeed low in undernourished people if no inflammatory illness is present. Methods We did a systematic review to identify otherwise healthy subjects who were severely nutrient-deprived due to poor access to food or unwillingness to eat. We excluded children and pregnant women. We tabulated available measures of nutrient intake, anthropometry, serum albumin and prealbumin, and, when available, changes in these measures during nutritional intervention. Results In otherwise healthy subjects, serum albumin and prealbumin levels remained normal despite marked nutrient deprivation until the extremes of starvation, that is, body mass index Conclusions In these otherwise healthy subjects, serum albumin and prealbumin levels are not "markers of nutritional status." The "markers" failed to identify subjects with severe protein-calorie malnutrition until extreme starvation. That is, they failed to identify healthy individuals who would benefit from nutrition support, becoming abnormal only when starvation was already obvious. In contrast, serum albumin and prealbumin levels are known to fall promptly with injury or illness regardless of nutrient intake. They are negative acute-phase reactants. When these measures are low in sick patients, this cannot be assumed to reflect nutritional deprivation. Decisions about nutrition support should be based on evidence of meaningful benefit from this treatment rather than on assessment of "nutritional markers."
Management Development Activities and Learning Interests of University Residence Hall Foodservice Managers

This study identified university residence hall foodservice managers' percep tions of training frequency, the degree of their learning interest on selected topics, and their demographic characteris...
From One-Cell to Tissue: Reprogramming, Cell Differentiation and Tissue Engineering

Adult somatic cells can be reprogrammed into pluripotent stem cells, which can indefinitely proliferate in a dish and differentiate into almost all the cell types that constitute the human body. These cells hold great promise for cell therapy and regenerative medicine, as well as drug screening and disease modeling. Theoretically, we can create a source of versatile, therapeutic cells that could be genetically matched to any patient. These pluripotent stem cells can be differentiated into desired cell types and eventually used to reconstruct a tissue or an organ with insights gained from tissue engineering. Inspired by the pioneering work in stem cells, particularly the remarkable reprogramming technique, the fields of regenerative medicine and tissue engineering have advanced rapidly in the past several years. Here recent progress in the fields of induced pluripotent stem cells and tissue engineering is reviewed, with a focus on applications in medicine.
Increased Phosphorylation of a Distinct Subcellular Pool of Protein Phosphatase, PP1γ2, During Epididymal Sperm Maturation

The enzyme PP1γ2 is a testis- and sperm-specific isoform of type 1 protein phosphatase (PP1), and it is the only isoform of PP1 in spermatozoa. The enzyme PP1γ2 is essential for spermatogenesis and is also a key enzyme in the development and regulation of sperm motility. The carboxy terminus of the enzyme contains a consensus amino acid sequence for phosphorylation by cyclin-dependent kinases. Using antibodies specific to this phosphorylated amino acid sequence domain, we found that phosphorylated PP1γ2 is present in bovine epididymal spermatozoa. The level of phosphorylated PP1γ2 is significantly higher in motile caudal compared to immotile caput epididymal spermatozoa. A number of treatments, such as 2-chloro adenosine, cAMP analogues, cAMP phosphodiesterase inhibitors, and calcium, which stimulate sperm motility, did not alter the level of phosphorylated PP1γ2. However, calyculin A, which is an inhibitor of protein phosphatase subtypes PP1 and PP2A, significantly increases the level of phosphorylated PP1γ2 in both caput and caudal epididymal spermatozoa. Partial purification by column chromatography showed that phosphorylated PP1γ2 is catalytically active. Phosphorylated PP1γ2 is the only spontaneously catalytically active form of the enzyme in caudal sperm extracts. Western blot analysis shows that the enzyme cyclin-dependent kinase 2, one of the enzymes that phosphorylates the consensus domain at the carboxy terminus in PP1 isoforms, is present in spermatozoa. Western blot analysis of proteins extracted from purified head and tail fragments of spermatozoa showed that phosphorylated PP1γ2 is present predominantly in the sperm head. Fluorescence immunocytochemistry also showed that phosphorylated PP1γ2 is present predominantly in the posterior region of the sperm head. The distinct subcellular localization and changes in its level during sperm maturation suggest a possible role for sperm phosphorylated PP1γ2 in signaling events during fertilization.
From first class to third class: recent upheaval in antiarrhythmic therapy--lessons from clinical trials.

Abstract In recent years, the results of large randomized and controlled trials of antiarrhythmic agents for primary and secondary prevention of ventricular tachycardia and ventricular fibrillation have changed perceptions of the actions of antiarrhythmic agents regarding both efficacy and risk. The premature termination of the CAST trials of primary prevention in postinfarct patients highlighted the proarrhythmic risk and inefficacy of the sodium channel blockers (class I action), encainide, flecainide, and moricizine, in patients at relatively low risk for death in the long term. The excess mortality with therapy was attributed to proarrhythmia due to facilitation of reentry, especially during acute ischemia. About the same time, European trials with amiodarone, a complex agent with antiadrenergic action and powerful action to prolong refractoriness (class III action), indicated enhanced survival after infarction with amiodarone but not with agents with class I action. Recent verbal reports of larger and placebo-controlled trials (EMIAT and CAMIAT) confirm a significant reduction in arrhythmia mortality, possibly with a favorable trend in total mortality. While an older trial with dl -sotalol (class III and β-blocking actions) showed a trend toward improved survival after infarction, a recent trial with d -sotalol in patients with recent infarction or remote infarction and heart failure was prematurely terminated because of excess mortality attributed to proarrhythmia (torsades de pointes), indicating the importance of β-blocking properties of a class III agent. A secondary prevention trial (ESVEM) in patients surviving an episode of VT or VF showed significant superiority of dl -sotalol compared to an array of agents that block sodium channels with respect to both efficacy and tolerance. Occurrence rates of arrhythmias treated with drugs tested for efficacy either by suppression of inducible arrhythmias or by suppression of spontaneous ectopy were higher and equivalent for both testing methods. A secondary prevention trial of amiodarone and multiple agents that block sodium channels in survivors of cardiac arrest (CASCADE) showed a significant increased efficacy of amiodarone but poorer long-term tolerance compared with the other agents. Comparative analysis of the results of the various trials suggests that class III action coupled with antiadrenergic action is more efficacious in both primary and secondary prevention of life-threatening ventricular arrhythmias and that lethal proarrhythmias may be the predominant effect in attempts at primary prevention in low-risk populations due to class I or so-called pure class III action. (Am J Cardiol 1996;78 (suppl 4A):28–33)
Determining user information goals in media-rich web sites by rethinking information scent theory

The “information goal” underlying user activity on the web is an important latent parameter. Its determination can help in a wide variety of tasks ranging from improving the quality of a search engine's results to design and evaluation of web sites. The problem of determining user information goals is exacerbated in media-rich websites. The complexity lies in the fact that the semantics as well as the user-content interactions associated with media-rich information are context-based, emergent, and hard to capture. Furthermore, simple summary data such as traversal history or links clicked are, by themselves, insufficient to obtain insights about the information needs of a user. Doing so requires an explanatory model of user action. In this paper we propose techniques for automatically estimating user information goals from usage patterns in media-rich sites. Our research builds on ideas from information foraging theory; specifically, we propose methods to capture the influence of media-rich information and its structure on information goals and re-think the classical notion of information scent to capture the subjective perception of the value/cost/access-path of media-based informational entities. Putative information goals can subsequently be estimated from browsing patterns. Experimental investigations study the efficacy of the proposed techniques for estimating user goals and user-content interaction patterns in complex media rich sites.
Youth Antecedents to News Media Consumption: Parent and Youth Newspaper Use, News Discussion, and Long-Term News Behavior

Intergenerational panel data are used to test a model of youth news socialization. We hypothesize that observing parent news reading and participating in family news discussions have concurrent effects on youth news use, ultimately resulting in a propensity for news consumption that persists into adulthood. Results from a recursive path model demonstrate parent communication variables have direct and indirect effects on frequency of youth news use. Frequency of youth news use, in turn, predicts news use among the same respondents 7 years later. We also find a latent, lagged effect of parent news reading on their kids’ long-term news use.
Fast and Accurate Statistical Criticality Computation Under Process Variations

With ever-shrinking device geometries, process variations play an increased role in determining the delay of a digital circuit. Under such variations, a gate may lie on the critical path of a manufactured die with a certain probability, called the criticality probability. In this paper, we present a new technique to compute the statistical criticality information in a digital circuit under process variations by linearly traversing the edges in its timing graph and dividing it into ldquozones.rdquo We investigate the sources of error in using tightness probabilities for criticality computation with Clark's statistical maximum formulation. The errors are dealt with using a new clustering-based pruning algorithm which greatly reduces the size of circuit-level cutsets improving both accuracy and runtime over the current state of the art. On large benchmark circuits, our clustering algorithm gives about a 250times speedup compared with a pairwise pruning strategy with similar accuracy in results. Coupled with a localized sampling technique, errors are reduced to around 5% of Monte Carlo simulations with large speedups in runtime.
Hydrostatic pressure reduces thrombogenicity of polytetrafluoroethylene vascular grafts

A prime factor in the thrombogenicity of synthetic materials in contact with blood is the blood-gas interface. Small pockets of gas, known as gas nuclei, are trapped within surface interstices. The resulting blood-gas interface denatures plasma proteins and activates clotting factors and platelets. Expanded polytetrafluoroethylene (ePTFE) vascular prostheses 1 mm in internal diameter were placed in saline under 6,000 psig hydrostatic pressure for 2 h in an attempt to dissolve all gas nuclei (i.e., to denucleate). Carotid-carotid bypasses were performed in rats using 280-mm lengths of ePTFE. All 10 control grafts lost patency in 5 min, whereas the 14 denucleated grafts had a median patency duration of 300 min (P less than 0.01). In 15-mm-long rat femoral artery interpositional ePTFE grafts, 90% of controls thrombosed within 10 min, whereas only 7% of denucleated grafts thrombosed over the duration of the 7-day observation period (P less than 0.001). Denucleation also resulted in a significant reduction (P less than 0.02) in 111In-labeled platelet adhesion to 36% of control. Scanning electron microscopy confirmed the reduced accumulation of platelets on denucleated grafts. These data suggest that the removal of trapped air with hydrostatic pressure significantly reduces the thrombogenicity of ePTFE microvascular prostheses and may have application to other clinical (catheters, valves, tubing, etc.) or experimental (micropipettes, electrodes, etc.) materials that interface with blood.
Detection and Clinical Patterns of Nephron Hypertrophy and Nephrosclerosis Among Apparently Healthy Adults

Background Even among ostensibly healthy adults, there is often mild pathology in the kidney. The detection of kidney microstructural variation and pathology by imaging and the clinical pattern associated with these structural findings is unclear. Study Design Cross-sectional (clinical-pathologic correlation). Setting & Participants Living kidney donors at Mayo Clinic (Minnesota and Arizona sites) and Cleveland Clinic 2000 to 2011. Predictors Predonation kidney function, risk factors, and contrast computed tomographic scan of the kidneys. These scans were segmented for cortical volume and medullary volume, reviewed for parenchymal cysts, and scored for kidney surface roughness. Outcomes Nephrosclerosis (glomerulosclerosis, interstitial fibrosis/tubular atrophy, and arteriosclerosis) and nephron size (glomerular volume, mean profile tubular area, and cortical volume per glomerulus) determined from an implantation biopsy of the kidney cortex at donation. Results Among 1,520 living kidney donors, nephrosclerosis associated with increased kidney surface roughness, cysts, and smaller cortical to medullary volume ratio. Larger nephron size (nephron hypertrophy) associated with larger cortical volume. Nephron hypertrophy and larger cortical volume associated with higher systolic blood pressure, glomerular filtration rate, and urine albumin excretion; larger body mass index; higher serum uric acid level; and family history of end-stage renal disease. Both nephron hypertrophy and nephrosclerosis associated with older age and mild hypertension. The net effect of both nephron hypertrophy and nephrosclerosis associating with cortical volume was that nephron hypertrophy diminished volume loss with age-related nephrosclerosis and fully negated volume loss with mild hypertension-related nephrosclerosis. Limitations Kidney donors are selected on health, restricting the spectrum of pathologic findings. Kidney biopsies in living donors are a small tissue sample leading to imprecise estimates of structural findings. Conclusions Among apparently healthy adults, the microstructural findings of nephron hypertrophy and nephrosclerosis differ in their associations with kidney function, macrostructure, and risk factors.
Absolute Calibration of Sims Depth Profiles of a-SiNx:H/a-Si:H and a-SiOx:H/a-Si:H Multilayers

We calibrated secondary ion mass spectrometry (SIMS) depth profiles of a-SiN x :H/a-Si:H and a-SiO x :H/a-Si:H multilayer samples by comparing them to high-spatial-resolution SIMS maps of cross sections through the layers. Both profiles and images were acquired with a focused scanning 45 keV Ga + ion microprobe. During depth profiling an area gating technique was used to improve depth resolution. At the beginning of the profile the resolution was 8 nm. By cutting the multilayer films at a small angle through the layers, we obtained SIMS images of cross sections through thesemultilayer samples. The resolution along the expanded direction is about 10 nm. By comparing the depth profiles and the cross section images, we determined the ionbeam-induced atomic mixing in the samples, as a function of depth and the sputtering yield for each layer.
Effective Damping of a Flexible-Matrix-Composite Laminate With a Negative Effective Poisson’s Ratio

Two very important factors which determine the effectiveness of a pump are its volumetric and energy efficiencies. Yin and Ghoneim constructed a prototype of a flexible body pump with a very high volumetric efficiency or pumping potential (the relative volume reduction due to a relative input stroke) [1]. The high volumetric efficiency is attributed to the geometry of the pump’s structure (hyperboloid) as well as the high negative effective Poisson’s ratio of the 3-layer ([θ/β/θ]) flexible-matrix-composite (carbon/polyurethane) laminate adopted for the body of the pump. The energy efficiency was not evaluated. An important factor in assessing the energy efficiency of flexible-body pumps is the effective damping (a measure of the energy dissipation per cycle) of the flexible body material. An objective of the current work is to determine the effective damping inherent in the 3-layer laminate, as a function of the two angle orientations θ and β, employed for the design of the flexible body pump. Thereby, the best fiber angle orientation, for the highest volumetric as well as energy efficiency, can be considered. The contribution of this work is twofold: 1) viscoelastic characterization (longitudinal, transverse, and shear complex moduli, as well as the in-plane complex Poisson’s ratio) of the polyurethane/carbon composite, used in the Geo-polymer lab at RIT; the results may be utilized as benchmarks for other researchers using similar carbon/polyurethane in dynamic applications, and 2) provide a comprehensive study of the effect of the two angles θ and β on the effective damping factors of the three-layer laminate. Together with the similar study on the negative Poisson’s ratio [1], a better design of the laminate for the most efficient flexible-body pump performance can be established.Copyright © 2015 by ASME
Minimally invasive repair of pectus excavatum

Pectus excavatum, an acquired or congenital depression of the anterior chest wall, is the most commonly occurring chest wall deformity. Patients with pectus excavatum experience psychosocial and physiologic consequences such as impaired social development and pulmonary and/or cardiac dysfunction as a result of the deformity. Traditionally, repair of the defect was performed with a major open operation, the most common being based on modifications of the Ravitch procedure. In the late 1990's, the operative approach was challenged with a new minimally invasive technique described by Dr. Donald Nuss. This approach utilizes thoracoscopic visualization with small incisions and placement of a temporary metal bar positioned behind the sternum for support it while the costal cartilages remodel. Since introduction, the minimally invasive repair of pectus excavatum (MIRPE) has become accepted in many centers as the procedure of choice for repair of pectus excavatum. In experienced hands, the procedure has excellent outcomes, shorter procedural length, and outstanding cosmetic results. However, proper patient selection and attention to technical details are essential to achieve optimal outcomes and prevent significant complications. In the following, we describe our perspective on pectus excavatum deformities, operative planning, and technical details of the MIRPE procedure.
Tuning Carbon-Based Fuel Cell Catalyst Support Structures via Nitrogen Functionalization. II. Investigation of Durability of Pt-Ru Nanoparticles Supported on Highly Oriented Pyrolytic Graphite Model Catalyst Supports As a Function of Nitrogen Implantation Dose

Nitrogen functionalization of carbon-based support materials for low-temperature fuel cell catalysts has been shown to improve catalyst–support interactions and therefore enhance both the performan...