cssi/SciSciGPT-SciSciNet huggingface dataset:
Methacryl-polyhedral oligomeric silsesquioxane as a crosslinker for expediting photo-crosslinking of Poly(propylene fumarate): Material properties and bone cell behavior

Abstract We present photo-crosslinkable hybrid organic-inorganic composites of poly(propylene fumarate) (PPF), an injectable and biodegradable polyester, and methacryl-polyhedral oligomeric silsesquioxane (mPOSS), which has eight methacryl groups tethered with a cage-like hybrid inorganic–organic nanostructure, for bone tissue engineering applications. Two PPF samples, one with a higher molecular weight (HPPF) and one with a lower molecular weight (LPPF), were blended with mPOSS at various mPOSS compositions. We emphasize on the role of mPOSS in modifying the photo-crosslinking kinetics of PPF and the physical properties of crosslinked products, and in regulating mouse pre-osteoblastic MC3T3-E1 cell behavior on the crosslinked substrates. The viscoelastic behavior of uncrosslinked PPF/mPOSS and the mechanical, degradation, and surface characteristics of photo-crosslinked PPF/mPOSS samples have been investigated. The crosslinking kinetics of PPF/mPOSS was characterized using the gel fraction and rheological properties such as storage modulus and viscosity of the samples crosslinked for 0.5–5 min. Blending mPOSS with PPF was found to decrease the viscosity of PPF and expedite the photo-crosslinking process, both of which are important in formation of PPF networks. In addition, tensile modulus was increased by crosslinking PPF with mPOSS up to the mPOSS composition of 15%, above which phase separation occurred. The degradation rate in 1 N NaOH solution could also be regulated by varying the mPOSS composition, while crosslinked PPF/mPOSS samples did not show detectable degradation in one week in phosphate buffered saline (PBS) and mPOSS did not significantly alter surface wettability and serum protein adsorption. MC3T3 cell adhesion, spreading, proliferation, differentiation, and gene expression were examined on crosslinked PPF/mPOSS disks. Addition of mPOSS did not introduce cytotoxicity or influence cell behavior evidently. It is interesting to note that crosslinked HPPF/mPOSS showed distinct physical properties and promoted MC3T3 cell functions compared with their LPPF counterparts possibly because of higher crosslinking densities.
Angiotensin-induced cyclic GMP production is mediated by multiple receptor subtypes and nitric oxide in N1E-115 neuroblastoma cells.

: Angiotensin II (AngII) elicited a rapid and dose-related production of intracellular cyclic GMP (cGMP) in murine neuroblastoma N1E-115 cells. The agonist-induced rise in cGMP levels was blocked in a monophasic fashion by the AT1-selective antagonist DuP 753 or the nonselective antagonist [Sarc1,Ile8]-AngII, and both antagonists produced complete inhibition of the cGMP response elicited by submaximal concentrations of AngII. In contrast, the AT2-selective antagonist CGP 42112A inhibited the cGMP response biphasically. At lower antagonist concentrations, agonist-induced cGMP production was only partially inhibited, whereas complete inhibition was observed only when the concentration of CGP 42112A was increased sufficiently to interact with both AT1 and AT2 receptor subtypes. AngII-also increased inositol trisphosphate (InsP3) levels in N1E-115 cells. However, the InsP3 response was mediated exclusively by the AT1 receptor subtype because it was inhibited by lower, AT1 selective concentrations of DuP 753, whereas only higher, nonselective concentrations of CGP 42112A were effective. Finally, the stimulatory effects of AngII on cGMP production appeared to be mediated by the intracellular formation of nitric oxide in that they were attenuated by the nitric oxide synthase inhibitor, N-monomethyl-L-arginine. Collectively, these results suggest that the AngII-elicited rise in cGMP levels may require an interaction between AT1-mediated mobilization of intracellular Ca2+, as well as some partial role of AT2 receptors.
The impedance boundary condition at a two-dimensional rough metal surface

Abstract We consider the system consisting of vacuum in the region x 3 > ζ( x ‖ ) and a metal characterized by an isotropic, frequency-dependent, dielectric function ϵ(ω) in the region x 3 x ‖ ) . The surface profile function ζ( x ‖ ) is a single-valued function of the vector x ‖ = (x 1 , x 2 , 0) that is differentiable as many times as is necessary. By the application of the vectorial form of Green's second integral identity to the region filled by the metal a pair of coupled integral relations between the two independent components of each of the vectors J E ( x ‖ |ω ) = n × E(x|ω) | x 3 =ζ(x ‖ ) and J H (x ‖ |ω) = n × H(x|ω) | x 3 =ζ(x ‖ ) is obtained, where E (x|ω) and H (x|ω) are the frequency Fourier components of the macroscopic electric and magnetic fields in the system, while n = ( −∂ζ(x ‖ ) ∂x 1 , −∂ζ(x ‖ ) ∂x 2 , 1) . A nonlocal relation between J E (x ‖ |ω) 1,2 and J H ( x ‖ | ω ) 1,2 is implied by these relations, and a local relation of the form J E ( x ‖ | ω ) i = K ij (0) ( x ‖ | ω ) J H ( x ‖ | ω ) j ( i , j = 1,2) is extracted from it. The two coupled integral equations satisfied by the elements of the 2 × 2 matrix K ij (0) ( x ‖ | ω ) are solved analytically to yield K ij (0) ( x ‖ | ω ) as an expansion in powers of the skin depth of the metal at the frequency ω of the electromagnetic field. The first two terms in this expansion are presented. The way in which nonlocal corrections to the relations between J E ( x ‖ | ω ) 1,2 and J H ( x ‖ | ω ) 1,2 can be obtained is also outlined.
The effects of various catecholamines on specific vascular hemodynamics in hypotensive and normotensive subjects.

Abstract Data are presented which indicate that all vasopressor sympathicomimetic amines do not act on the same regional vascular bed in the same manner. For example, administration of one amine may cause marked renal vasoconstriction in relation to general vasoconstriction, whereas another may cause only slight renal vasoconstriction. Preliminary evidence suggests that such differences may exist as far as cerebral vasculature is concerned. The data suggest that consideration should be given to the total pharmacologic action of a vasopressor drug rather than only to its potency in raising blood pressure.
Band structure calculation for quantum dot solar cells using k.p method

Quantum dot hetero structures are possible candidate materials for high efficiency solar cells using advanced approaches such as intermediate bands. Lattice mismatch in the epitaxial growth of quantum dot (QD) causes strain in the structure. Here we report the use of the k.p method to calculate the band structure including the effects of strain, and light and heavy holes. With the modified band gaps due to strain, a material search is performed among III-V binaries and ternaries for a high efficiency QD solar cell material with negligible valence band offsets. It is found that the condition of negligible valence band offsets severely limits the choice of materials. The closest to ideal barrier/dot material system found is Al 0.57 In 0.43 As/InP 0.87 Sb 0.13 corresponding to an efficiency of 58% under x1000 solar concentration for AM 1.5 spectrum.
Experience with the ADAM Synthesis System

The ADAM synthesis system consists of two major subsystems: the program tools which synthesize RTL designs from behavioral descriptions and the prediction tools which guide the designer in exploring the design space for a good design. In this paper, we demonstrate the necessity for predictions in narrowing the search space. With the aid of an example, we describe the interaction of a designer with the two subsystems in designing an RTL implementation which maximizes performance while meeting a given area constraint.
What can public health nutritionists do to curb the epidemic of nutrition‐related noncommunicable disease?

As a result of the rapid shift in dietary and activity patterns, the world is facing a pandemic of obesity. This new global pandemic is rapidly becoming a problem of the poor. Extensive work has been undertaken to document the changes in weight and, to a much lesser extent, in diet, energy expenditures, and activity patterns. Broad-based creative public health actions are needed to offset these larger forces that promote energy imbalance, poor diets, and reduced physical activity. Inaction will result in an acceleration of morbidity, disability, and deaths from major nutrition-related noncommunicable diseases - primarily in developing countries.
Greenhouse gas emissions and biogas potential from livestock in Ecuador

article i nfo Article history: Received 27 September 2010 Accepted 27 September 2010 Greenhouse gas emissions inventories provide a baseline to develop mitigation projects for reducing emissions. However, a detailed inventory of livestock gas emissions is not available for Ecuador. This study attempts to fill this gap. The methodology selected comes from the 2006 Intergovernmental Panel on Climate Change guidelines toquantify emissions from thelivestock sector. Tier 1methodology wasimplemented using animal census data for the year 2000, and historical temperature data by province. The total methane emissions from enteric fermentation were 5596 GgCO2Eq.Methane emissions from manure came mainly from cattle and swine with 92.4 and 44.3 GgCO2Eq, respectively, and a livestock total of 182 GgCO2Eq. The total direct nitrous oxide (N2O) emissions from manure management were 172 GgCO2Eq, and total direct and indirect N2O emissions from manure deposited on soils by grazing livestock were 2176 GgCO2Eq. A further 103 GgCO2Eq of direct N2O emissions came from the application of confined-livestock manure to soils. We estimated the total potential reductions in emissions from capturing methane gas from anaerobic digestion of dairy, swine and poultry manure and substituting methane for liquefied petroleum gas (LPG) at 308 GgCO2Eq. The value of the methane produced could amount to US$ 77 M. Alternatively, that same methane gas could be used to generate 275 GWh of electricity. Additional benefits from anaerobic digestion of manure include the recovery of nutrients from the digested effluent, which could be used as biofertilizer and soil amendment. The capture of these greenhouse gases and the use of anaerobic digesters to produce energy and other products seem to have potential in Ecuador. However, lack of experience with anaerobic digestion and biogas production is a great limitation for the implementation of this technology. Also, anaerobic digester designs should be evaluated and modified to fit local needs given the variability of climatic and socio-economic conditions across the country.
Optical burst switching reservation process modeling and analysis

Optical burst switching (OBS) supports IP-over-photonics for future QoS-supporting Internet through combining advantages of electronic control processing and optical transmission. The resource reservation is critical for OBS. In this paper we examine optical burst switching (OBS) reservation process and discuss the most important parameters and their impact on the performance of the reservation process. A general framework for its modeling and analysis is presented. We model OBS reservation using queueing networks. Our framework and model cover all aspects of OBS reservation process including control packet arrival, offset time assignment. control packet processing, optical switch matrix setup, data burst arrival and transmission. Current models and analysis only consider offset time assignment and data burst arrival and transmission its OBS reservation. Further we show that even though widely assumed and used, conservation law does not hold generally for average burst loss probability for reservation processes which support multiple priority classes.
Feminist poststructuralism: a methodological paradigm for examining clinical decision-making.

Feminist poststructuralism: a methodological paradigm for examining clinical decision-making Aim. To present the philosophical framework of feminist poststructuralism, discuss its use as an innovative research approach and its implications for nursing knowledge development and practice. Background. This perspective examines the construction of meaning, power relationships, and the importance of language as it affects contemporary healthcare decisions. It seeks to identify and expose biases that marginalize the healthcare needs of women and contribute to healthcare disparities for this population. Additionally, a feminist poststructuralist perspective seeks to develop new knowledge for understanding gender differences. Nursing application. A feminist poststructuralist perspective represents an alternative paradigm for studying the phenomenon of clinical decision-making. An empirical application example of a feminist poststructuralist perspective is provided. This exemplar investigated emergency department registered nurses’ triage decisions for men and women with symptoms suggestive of coronary heart disease.
Dietary micronutrient intake and risk of progression to acquired immunodeficiency syndrome (AIDS) in human immunodeficiency virus type 1 (HIV-1)-infected homosexual men

The authors sought to determine if different levels of dietary intake of micronutrients are associated with the progression of human immunodeficiency virus type 1 (HIV-1) infection to acquired immunodeficiency syndrome (AIDS). A total of 281 HIV-1 seropositive homosexual/bisexual men were seen semiannually since 1984 at the Baltimore/Washington, DC site of the Multicenter AIDS Cohort Study. Participants completed a self-administered semiquantitative food frequency questionnaire at baseline. Levels of daily micronutrient intake at baseline were examined in relation to subsequent progression to AIDS (1987 Centers for Disease Control definition; n = 108) during a median follow-up period of 6.8 years. For each nutrient, the authors used a Cox proportional hazards model to adjust for age, presence of symptoms, CD4+ lymphocyte count, energy intake, use of antiretrovirals, and use of Pneumocystis carinii pneumonia prophylaxis. The highest levels of total intake (from food and supplements) of vitamins C and B1 and niacin were associated with a significantly decreased progression rate to AIDS: vitamin C (relative hazard (RH) = 0.55, 95% confidence interval (CI) 0.34-0.91), vitamin B1 (RH = 0.60, 95% CI 0.36-0.98), and niacin (RH = 0.52, 95% CI 0.31-0.86). The relation between total vitamin A intake and progression to AIDS appeared to be U-shaped; the lowest and highest quartiles of intake did most poorly, while the middle two quartiles were associated with significantly slower progression to AIDS (RH = 0.55, 95% CI 0.35-0.88). Increased intake of zinc was monotonically and significantly associated with an increased risk of progression to AIDS (for highest vs. lowest quartiles, RH = 2.06, 95% CI 1.16-3.64). In a final multinutrient model, vitamin A, niacin, and zinc remained significantly associated with progression to AIDS, while vitamin C was only marginally significant.
Comprehension of lexical subcategory distinctions by aphasic patients: proper/common and mass/count nouns.

Previous research has found that agrammatic Broca aphasic patients have particular difficulty using determiners like "a" and "the" for the purposes of sentence comprehension. In this study, we test whether or not such difficulty extends to the level where lexical subcategories are distinguished by these articles. The absence or presence of a determiner distinguishes proper from common nouns (e.g., "ROSE vs. "A ROSE"), and mass from count nouns (e.g., "GLASS" vs. "A GLASS"). Groups of agrammatic Broca and fluent aphasic subjects were required to point to one of two pictures in response to a sentence such as "Point to the picture of rose" or "Point to the picture of a rose". Sentences were presented in either printed or spoken form. Results indicated that for the agrammatic Broca patients, printed presentation yielded significant improvement over spoken presentation only for the proper noun/common noun distinction. Performance was significantly poorer for the mass noun/count noun distinction as compared to ...
Inequality in Preschool Education and School Readiness

Attendance in U.S. preschools has risen substantially in recent decades, but gaps in enrollment between children from advantaged and disadvantaged families remain. Using data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999, we analyze the effect of participation in child care and early education on children's school readiness as measured by early reading and math skills in kindergarten and first grade. We find that children who attended a center or school-based preschool program in the year before school entry perform better on assessments of reading and math skills upon beginning kindergarten, after controlling for a host of family background and other factors that might be associated with selection into early education programs and relatively high academic skills. This advantage persists when children's skills are measured in the spring of kindergarten and first grade, and children who attended early education programs are also less likely to be retained in kindergarten. In most instances, the effects are largest for disadvantaged groups, raising the possibility that policies promoting preschool enrollment of children from disadvantaged families might help to narrow the school readiness gap.
Polysaccharide Krestin is a novel TLR2 agonist that mediates inhibition of tumor growth via stimulation of CD8 T cells and NK cells

Purpose: Polysaccharide krestin (PSK) is a mushroom extract that has been long used in Asia and recently in Western countries as a treatment for cancer due to its presumed immune potentiating effects. Although there have been reports of clinical responses after patients have ingested PSK, the mechanism of action of the agent remains undefined. The current study was undertaken to investigate the mechanism of the antitumor actions of PSK. Experimental Design: The immunostimulatory effect of PSK was first evaluated in vitro using splenocytes from neu transgenic mice and Toll-like receptor (TLR) 2 knockout (TLR2 −/− ) mice. Then the immunostimualtory and antitumor effect of PSK was determined using tumor-bearing neu transgenic mice, TLR2 −/− , and wild-type C57BL/6 mice. Results: We demonstrate that PSK is a selective TLR2 agonist, and the activation of dendritic cells (DC) and T cells by PSK is dependent on TLR2. Oral administration of PSK in neu transgenic mice significantly inhibits breast cancer growth. Selective depletion of specific cell populations suggests that the antitumor effect of PSK is dependent on both CD8 + T cell and NK cells, but not CD4 + T cells. PSK does not inhibit tumor growth in TLR2 −/− mice suggesting that the antitumor effect is mediated by TLR2. Conclusion: These results demonstrate that PSK, a natural product commonly used for the treatment of cancer, is a specific TLR2 agonist and has potent antitumor effects via stimulation of both innate and adaptive immune pathways. Clin Cancer Res; 17(1); 67–76. ©2010 AACR .
First- and Second-Language Reading Comprehension of Literary Texts.

This study compared the English and French reading comprehension and inferencing skills of U.S. college students enrolled in an introductory French literature course. Participants each read two different texts—one in English and the other in French—by the same 18th-century author, recalled them in writing, and did a multiple-choice task on selected literary features, followed by a character analysis task. In the first phase of data analysis, quantitative measures were used to examine the amount of text accurately recalled in first language (L1) versus second language (L2), the relationship between recall and inferencing scores, and the relative contribution of L2 proficiency scores and L1 scores to L2 scores. Responses to the multiple-choice task were also examined across languages; those findings are also reported. The results revealed more accurate recall of L1 than L2 texts, but L1 scores were found to be a significant predictor of L2 recall and of L2 multiple-choice scores. No significant relationships were found between recall and multiple-choice scores, or between L2 proficiency and L2 recall scores. Analyses revealed that L1 scores contributed more to L2 performance than did L2 proficiency. Multiple-choice responses were more similar than different across languages. It is therefore important for researchers and instructors to consider and assess the L1 reading skills and knowledge sources of students enrolled in foreign language literature courses.
Nucleolar DNA in oocytes of crickets: representatives of the subfamilies Oecanthinae and Gryllotalpinae (Orthoptera: Gryllidae).

A large extrachromosomal mass of Feulgen positive material, the DNA body, has been visualized in early prophase oocytes of crickets (Orthoptera: Gryllidae) representative of the closely related subfamilies Gryllinae and Nemobiinae. A similar structure is present in oocytes of representatives of two subfamilies of crickets (subfamilies Oecanthinae and Gryllotalpinae) which taxonomically and phylogenetically are quite separate from those mentioned previously. In situ hybridization demonstrates that the body contains amplified copies of genes coding for ribosomal RNA. Unlike the DNA body in early diplotene oocytes of representatives of the subfamily Gryllinae, which is closely associated with the developing nucleolar apparatus, the DNA body in oocytes of the Oecanthinae and Gryllotalpinae cannot be demonstrated during diplotene. In the Oecanthinae, the nucleolar apparatus of early diplotene stage oocytes is composed of four to seven separate structures, the ribonucleoprotein of which has a characteristically lamellated appearance. During late diplotene, these nucleoli give rise to many smaller structures which are distributed throughout the germinal vesicle. In early diplotene stage oocytes of Scapteriscus acletus (Subfamily: Gryllotalpinae), the nucleolar apparatus consists of a single compact mass of ribonucleoprotein. In contrast to the oocytes of all other crickets that have been studied, the nucleolus of S. acletus remains single throughout diplotene. In situ hybridization analysis indicates that the amplified genes coding for rRNA which are localized in the DNA body of early prophase oocytes become incorporated into this compact nucleolar mass. Differences in nucleolar structure appear to reflect differences in the organization of amplified genes coding for rRNA.
The Future of the Radiology Information System

OBJECTIVE. Today in the hospital setting, several functions of the radiology information system (RIS), including order entry, patient registration, report repository, and the physician directory, have moved to enterprise electronic medical records. Some observers might conclude that the RIS is going away. In this article, we contend that because of the maturity of the RIS market compared with other areas of the health care enterprise, radiology has a unique opportunity to innovate. CONCLUSION. While most of the hospital enterprise spends the next several years going through the digital transformation converting from paper to a digital format, radiology can leap ahead in its use of analytics and information technology. This article presents a summary of new RIS functions still maturing and open to innovation in the RIS market.
Direct and indirect assortative mating: a multivariate approach to plant flowering schedules

This paper develops methods to partition the phenotypic correlation between mates for a focal trait ‐ the standard measure for assortative mating ‐ into a direct component and additional indirect components. Indirect assortative mating occurs when a nonassorting trait is correlated within individuals to a directly assorting trait. Direct and indirect assortative mating is assessed for flowering phenology in Brassica rapa. The flowering time of pollen recipients (mothers) was strongly correlated (q ¼ 0.67) to that of potential pollen donors (fathers). Similarly, recipients and donors were correlated for duration of their flowering periods (q ¼ 0.32) and stem diameters (q ¼ 0.52). A partitioning of between-mate correlations revealed direct assortative mating for flowering time and period duration. However, assortment for stem diameter is explained solely through its correlation to flowering time. Examination of standard quantitative genetic theory shows that indirect assortative mating inflates genetic variance in a focal trait and the genetic covariance between focal and phenotypically correlated traits.
Differences in outer membrane characteristics between gallstone-associated bacteria and normal bacterial flora

Previous studies with scanning electron microscopy (SEM) have suggested that pigment gallstones contain bacteria. We set out to culture these bacteria and to study their membrane characteristics. We studied gallstones from 54 patients (36 men, 18 women; mean age 55.4 years) admitted consecutively to two hospitals for cholecystectomy. SEM detected bacteria in all of 14 brown pigment stones, 2 of 14 black pigment stones, and in the pigmented centres of 9 of 19 mixed cholesterol stones; no bacteria were detected in 14 pure cholesterol stones or within the cholesterol portions of mixed stones. We were able to culture bacteria from all gallstones with bacteria seen on SEM and for which sufficient material was available (n = 16). 20 bacterial species were recovered from these stones. Gallstones containing bacteria were associated with clinical sepsis and cholangitis. All bacteria obtained from gallstones agglutinated human O P1 erythrocytes, which reflects the presence of P1-specific fimbriae. 5 strains were positive for Forssman-antigen-specific fimbriae. None showed evidence of mannose-specific fimbriae. All of the organisms bound anti-Gal, a ubiquitous naturally occurring IgG specific for alpha-galactosyl residues. The presence of P1 fimbriae and alpha-galactosyl residues and the absence of mannose-specific fimbriae distinguish these organisms from gut flora. We postulate that possession of these unusual properties may enhance the ability of bacteria to colonise the biliary tree and initiate pigment gallstone formation.
Projective Systems in Large Deviation Theory II: Some Applications

In the recent papers [5], [6] we proved some general results on large deviations for projective systems and showed how they apply to certain specific situations. The purpose of this note is to present some additional applications.
What's happening to the boys? Early high school experiences and school outcomes among African American male adolescents in Chicago.

This article examines the transition to high school among African American males who were part of a longitudinal study in Chicago. It begins with a comparison of gender differences in school performance from 8th to 12th grade. It then presents an in-depth qualitative look at the experiences of the 15 males in the longitudinal study. In 8th grade, there were few gender differences in school performance or teachers' ratings of students' behavior and skills. African American males experienced much more dramatic declines than females in their grades between 8th and 9th grade and were viewed more negatively by their 9th grade teachers. Ultimately, only 40% of the males graduated compared to 80% of the females. By looking carefully at individual students' experiences, this article seeks to gain insight into the school, peer, familial and developmental processes that shape the school performance of African American males over this critical period.
Measurement of Mass-Based Carbon Nanotube Penetration through Filtering Facepiece Respirator Filtering Media

Recent studies suggest that a wide range of human health effects could result from exposure to carbon nanotubes (CNTs). A National Institute for Occupational Safety and Health survey of the carbonaceous nanomaterial industry found that 77% of the companies used respiratory protection, such as filtering facepiece respirators (FFRs). Despite CNT studies in some occupational settings being reported, the literature for mass-based penetration of CNTs through FFRs is lacking. The aim of this study was to conduct a quantitative study of single-walled CNT (SWCNT) and multiwalled CNT (MWCNT) penetration through FFRs. A CNT aerosol respirator testing system was used to generate charge-neutralized airborne SWCNTs and MWCNTs for this study. The size distribution was 20–10000nm, with 99% of the particles between 25 and 2840nm. Mass median diameters were 598 and 634nm with geometric standard deviations of 1.34 and 1.48 for SWCNTs and MWCNTs, respectively. Upstream and downstream CNTs were collected simultaneously using closed-face 3.7-cm-diameter filter cassettes. These samples were subsequently analyzed for organic carbon and elemental carbon (EC), with EC as a measure of mass-based CNTs. The mass-based penetration of SWCNTs and MWCNTs through six FFR models at constant flow rates of 30 l min−1 (LPM) was determined. Generally, the penetrations of SWCNTs and MWCNTs at 30 LPM had a similar trend and were highest for the N95 FFRs, followed by N99 and P100 FFRs. The mass-based penetration of MWCNTs through six FFR models at two constant flow rates of 30 and 85 LPM was also determined. The penetration of MWCNTs at 85 LPM was greater compared with the values of MWCNTs at 30 LPM.
On the stability of sampled-data linear time-varying feedback systems

In this paper the stability of systems consisting of a continuous-time, linear time-varying plant with a discrete-time, linear time-varying feedback controller is analysed. It is shown that provided that the hybrid system is uniformly exponentially stable, then the feedback system will be input-output stable. It is also shown that exponential stability of the system can be guaranteed by ensuring that a related discrete-time system is exponentially stable. These results generalize results of Chen and Francis (1991) who consider time-invariant plants. >
Revealing the Role of Phosphatidylserine in Shear Stress-Mediated Protection in Endothelial Cells

Previous studies have demonstrated that endothelial cells exposed to laminar shear stress are protected from apoptotic stimuli such as tumor necrosis factor (TNF)-alpha. The authors investigated the role of phosphatidylserine (PS) in this phenomenon. Western blot analysis of cleaved caspase 3 was used as an indicator of apoptosis and revealed that in the absence of serine, endothelial cells exposed to laminar shear stress were unable to protect against TNF-alpha-induced apoptosis, in contrast to sheared cells grown in regular medium. It was also found that shear-induced activation of the Akt pathway was significantly decreased in cells grown without serine. In addition, quantitation of PS using a novel isotopic labeling technique involving the use of formalin revealed that stearoyl-oleic PS (18:0/18:1) did not increase during shear treatment. These findings suggest that basal levels of PS are required to activate survival pathways in endothelial cells and thereby contribute to the overall protective mechanism initiated by shear stress.
Evaluating the Evidence Is There a Rigid Hierarchy

Health outcomes research applies a wide range of methods to identify optimal approaches to determine optimal approaches to determine the effects of healthcare interventions and policies. Critical evaluation skills are necessary to navigate the evidence and identify studies that should influence clinical decision making and policy. A hierarchical “pyramid of evidence” that emphasizes randomized controlled clinical trials (RCTs) has been promulgated as the approach to judging study design and quality. Whereas this hierarchy may be suitable for the evaluation of efficacy, it may be inappropriate for many health outcomes research questions. This article examines the relevance of this construct to questions beyond those of therapeutic efficacy and discusses the essential role of study designs beyond RCTs. The strengths and weaknesses of study designs commonly encountered in the medical literature are reviewed. The article concludes with 2 case studies that apply the concepts reviewed and illustrate the need to match the study design with the research question. Of note, the concepts of internal validity, external validity, confounding, and bias are central to the discussion of the strengths and weaknesses of study designs in the medical literature. Readers not familiar with these concepts should refer to the Appendix in the online-only Data Supplement for clarification. ### The Pyramid of Evidence: A Useful Construct? Traditionally, the design of a study has been considered a principal barometer of the validity of its findings. In this construct, different study designs are considered in the context of a pyramid of evidence, in which studies most susceptible to threats to internal validity reside at the bottom and those least prone reside at the top (Figure). This hierarchy is widely used in discussions about the quality of medical studies and is integrated into the grading of evidence in practice guidelines.1 However, although the pyramid of evidence is undoubtedly well suited for questions of therapeutic efficacy, …
On-line biomass estimation using a modified oxygen utilization rate

A procedure for estimating biomass during batch fermentation from on-line gas analysis is presented. First, the respiratory quotient was used to determine the fraction of the total oxygen utilization rate required for cell maintenance and growth versus product synthesis. The modified oxygen utilization rate was then used to estimate biomass on-line by integrating the oxygen balance for cell synthesis-maintenance. The method is illustrated for the case of L-lysine synthesis by Corynebacterium glutamicum.
Efficient FDTD wideband matched sources for a homogeneous waveguide cross-section

A finite difference time domain (FDTD) wideband matched source, for waveguide problems, is developed by the FDTD diakoptics method. The efficiency of this matched source is obtained by using the modal amplitude, instead of the 2-D transverse field, to represent the incident and reflected waves. The performance of this matched source is demonstrated by the S-parameter calculation of an inductive iris and a back short. Comparisons with other matched sources with first-order absorbing boundary condition (ABC) and superabsorbing conditions are also provided.
Insights into eukaryotic primer synthesis from structures of the p48 subunit of human DNA primase.

Abstract DNA replication in all organisms requires polymerases to synthesize copies of the genome. DNA polymerases are unable to function on a bare template and require a primer. Primases are crucial RNA polymerases that perform the initial de novo synthesis, generating the first 8–10 nucleotides of the primer. Although structures of archaeal and bacterial primases have provided insights into general priming mechanisms, these proteins are not well conserved with heterodimeric (p48/p58) primases in eukaryotes. Here, we present X-ray crystal structures of the catalytic engine of a eukaryotic primase, which is contained in the p48 subunit. The structures of p48 reveal that eukaryotic primases maintain the conserved catalytic prim fold domain, but with a unique subdomain not found in the archaeal and bacterial primases. Calorimetry experiments reveal that Mn2 + but not Mg2 + significantly enhances the binding of nucleotide to primase, which correlates with higher catalytic efficiency in vitro. The structure of p48 with bound UTP and Mn2 + provides insights into the mechanism of nucleotide synthesis by primase. Substitution of conserved residues involved in either metal or nucleotide binding alter nucleotide binding affinities, and yeast strains containing the corresponding Pri1p substitutions are not viable. Our results reveal that two residues (S160 and H166) in direct contact with the nucleotide were previously unrecognized as critical to the human primase active site. Comparing p48 structures to those of similar polymerases in different states of action suggests changes that would be required to attain a catalytically competent conformation capable of initiating dinucleotide synthesis.
Specific α4β2 Nicotinic Acetylcholine Receptor Binding of [F-18]Nifene in the Rhesus Monkey

Objective [F-18]Nifene is a PET radioligand developed to image α4β2* nicotinic acetylcholine receptors (nAChR) in the brain. This work assesses the in vivo binding and imaging characteristics of [F-18]nifene in rhesus monkeys for the development of PET experiments examining nAChR binding.
The effect of vasectomy and oviduct section on mouse behavior (38554).

This study was undertaken to determine the effect of vasectomy and tubal section on spontaneous locomotive movement and exploratory behavior in mice which might reflect an alteration in endocrine function. Adult Swiss Webster mice were either vasectomized tubectomized castrated or sham-operated upon. Controls were not operated on. 45 days after operation spontaneous movement in a box was recorded by an electronic field and exploratory behavior was d:termined from activities in another box with marked lines which recorded searching activities. Spontaneous movement was 1.7 greater in normal or sham-operated mice than in vasectomized (p less than .001) and 1.3 times greater than in castrate animals (p less than .05). Tubectomy and ovariectomy had the same effects as vasectomy or castration but with more variability. Exploratory behavior was slightly less in tubectomized mice. It was concluded that vasectomized or tubectomized mice had 60% less spontaneous movement than normal mice 45 days after operation; exploratory behavior was not significantly influenced by either operation. Results do not confirm findings reported by others than vasectomy enhances testosterone secretion or rejuvinates the organism. A degenerative effect is suggested.
InAlAs solar cells grown by alternative MOVPE precursors

Epitaxial layers of InAlAs are potential candidates for the top cell in triple-junction photovoltaics on InP. Growth conditions during metalorganic vapor phase epitaxy (MOVPE) of InAlAs affect the material properties and subsequently the device characteristics of the epilayers. Material development of InAlAs lattice-matched to InP using trimethylaluminum (TMAl) and tritertiarybutyl aluminum (TTBAl) is compared. Furthermore, InAlAs development using TTBAl is compared in conjunction with either arsine or tertiarybutylarsine (TBAs). Identical devices were grown from each aluminum source and are fabricated in parallel. The TTBAl/TBAs-InAlAs may have degraded during growth due to gas phase pre-reactions and resulted in a 6% efficient cell. However, using arsine, the TMAl-InAlAs devices showed maximum efficiency of 11.5% under 1-sun AM1.5, while TTBAl-InAlAs devices showed 12% (both without anti-reflective coatings). Dark current-voltage measurements of TMAl-InAlAs indicate higher material quality, though TTBAl-InAlAs has greater spectral response.
Shift operators defined in the Riordan group and their applications

Abstract In this paper, we discuss a linear operator T defined in Riordan group R by using the upper shift matrix U and lower shift matrix U T , namely for each R ∈ R , T : R ↦ U R U T . Some isomorphic properties of the operator T and the structures of its range sets for different domains are studied. By using the operator T and the properties of Bell subgroup of R , the Riordan type Chu–Vandermonde identities and the Riordan equivalent identities of Format Last Theorem and Beal Conjecture are shown. The applications of the shift operators to the complementary Riordan arrays and to the Riordan involutions and Riordan pseudo-involutions are also presented.
A Circumstellar Dust Disk around T Tauri N: Subarcsecond Imaging at λ = 3 Millimeters

We present high-resolution imaging of the young binary T Tauri in continuum emission at ? = 3 mm. Compact dust emission with integrated flux density 50 ? 6 mJy is resolved in an aperture synthesis map at 05 resolution and is centered at the position of the optically visible component, T Tau N. No emission above a 3 ? level of 9 mJy is detected 07 south of T Tau N at the position of the infrared companion, T Tau S. We interpret the continuum detection as arising from a circumstellar disk around T Tau N, and estimate its properties by fitting a flat-disk model to visibilities at ? = 1 and 3 mm, and to the flux density at ? = 7 mm. Given the data, probability distributions are calculated for values of the free parameters, including the temperature, density, dust opacity, and disk outer radius. The radial variation in temperature and density is not narrowly constrained by the data. The most likely value of the frequency dependence of the dust opacity, ?=0.53 -->?0.17+0.27, is consistent with that of disks around other single T Tauri stars in which grain growth is believed to have taken place. The outer radius, R=41 -->?14+26 AU, is smaller than the projected separation between T Tau N and T Tau S, and may indicate tidal or resonance truncation of the disk by T Tau S. The total mass estimated for the disk, log (MD/M?) = -2.4 -->?0.6+0.7, is similar to masses observed around many single pre-main-sequence sources and, within the uncertainties, is similar to the minimum nebular mass required to form a planetary system like our own. This observation strongly suggests that the presence of a binary companion does not rule out the possibility of formation of a sizable planetary system.
Buckling mode localization in multi-span columns

The mode-localization phenomenon is utilized in order to passively control structural buckling. An exact treatment is presented for the buckling problem of a multi-span column that involves certain irregularities, including intermediate torsional springs and/or displaced intermediate supports. The buckled mode shapes show that the buckling is confined to a limited part of the structure.
THE POPULATION BIOLOGY OF ANNUAL GRASSLAND HEMIPARASITES. II. REPRODUCTIVE PATTERNS IN ORTHOCARPUS.

Members of the genus Orthocarpus, like many annual hemiparasites, will form haustorial connections (root grafts) with a majority of their grassland associates. Orthocarpus faucibarbatus formed root grafts with every kind of plant with which it was grown in cultivation (Thurman, 1965). This included 23 species in 16 families, and three species not normally associated in nature. Cannon (1909) reported members of a single population of 0. purpurascens grafted to individuals representing 18 genera in 13 families. The ability to form vascular root connections with individuals from a wide range of species does not, however, imply that all such plants are suitable hosts. In the preceding paper (Atsatt and Strong, 1970) it was noted that promiscuous root grafting can be a liability as well as an asset because some hosts reduce the reproductive potential of their parasitic partners. Yet each year Orthocarpus individuals reestablish what appear to be random host relationships. Consequently, it is of particular interest to understand how the regulation of genetic variability in Orthocarpus populations is correlated with the extremely heterogeneous host-environment found within the grassland habitat. This paper relates data on the reproductive biology of Orthocarpus to the hemiparasitic mode of life. Attention is focused on ten Orthocarpus species found mostly in the coastal, valley, and foothill grasslands of California. They are 0. attenuatus Gray, castillejoides Benth., densiflorus Benth., linearilobus Benth., purpurascens Benth., and brevistylus Hoover of the subgenus Orthocarpus, and 0. erianthus Benth., faucibarbatus Gray, floribundus Benth., and pusillus Benth. of the subgenus Triphysaria. Members of these two groups are morphologically and cytologically distinct, but exhibit similar patterns in distributions, habitat, breeding systems, and natural hybridization. The remaining 15 species constituting the genus are primarily montane, with distributions extending over many of the western states.
PHENYLKETONURIA AND NUTRITION.

The cause of phenylpyruvic oligophrenia, a hereditary mental disease, is now largely understood.Practical, inexpensive and reliable methods of screening detect the presence of the disease.The development of phenylpyruvic oligophrenia and its pathologic results can be prevented by placing the newborn infant on a special diet.This disease can and should be eradicated.
Management of Primitive Neuroectodermal Tumor of the Kidney with Inferior Vena Cava Thrombus

Primitive neuroectodermal tumors (PNET) are an aggressive group of small round cell tumors usually arising in the nervous system and affecting children. They have a tendency for local invasion, distant spread and formation of tumor thrombi. The kidney is a rare primary location for these tumors. Outcomes are frequently poor due to late diagnosis (Wilms tumor is a more common tumor in this population) and early spread. Immunohistochemistry is invaluable in making the diagnosis of PNET. We report a case of a primary renal PNET with extensive tumor thrombus into the inferior vena cava, and lung metastasis in a pediatric patient, and its successful management. Our 14-year-old patient with renal PNET was managed with radical nephrectomy, thrombectomy and chemotherapy and remains disease free to date. The diagnosis of renal PNETs should be considered in young adult patients who present with aggressive renal masses at initial presentations. Despite its aggressive nature, good outcomes can be achieved by a multimodality therapeutic strategy.
Utility of the Surgical Apgar Score in Kidney Transplantation: Is it Feasible to Predict ICU Admission, Hospital Readmission, Length of Stay, and Cost in This Patient Population?

Background:This study analyzed the utility of the Surgical Apgar Scoring (SAS) system in predicting morbidity in kidney transplantation. Recipient comorbidities were evaluated for any effect on the...
Should Doctoral Programs Produce Teachers

This paper briefly highlights a survey taken of students in marketing doctoral programs across the U.S. It reports that students are concerned about the lack of preparation they receive for teaching. The authors suggest that doctoral programs should be sensitive to this concern on the part of their students.
“If I knew the language, don’t think that I would be here”: Shifting Understandings of the Linguistic Capital of English

Mariano was a highly skilled worker with extensive experience in several trades who thought that not speaking English held him back because he could not get the kind of work he was qualified to do with Anglo employers. Mariano emigrated from El Salvador to Mexico at the age of 20 escaping the violent civil war that was unfolding. He lived in Chiapas for 17 years, and eventually left for Ciudad Juarez, where he lived for six years. Frustrated with a lack of work in Juarez, he went back to San Salvador for a short time but then decided to come to the United States. When I met Mariano, he had been in Saguaro City for two years and was planning on staying indefinitely. He spoke nostalgically of Chiapas, which he identified as his adopted home, but made no indication of wanting to return to live there or in El Salvador permanently, in part because he had fallen out of contact with family members in both countries. Although he had no family in Saguaro City, Mariano proudly spoke of setting up his own small apartment and wanted to learn English because he saw it as a way to increase his employment opportunities, dreaming of someday being selfemployed. Mariano was a dedicated leader at the Day Labor Center (DLC) and donated significant time and energy to the program. Taking on a leadership role sometimes led to conflicts with other workers, who accused Mariano of cherry-picking jobs when he was in charge of the hiring list.