cssi/SciSciGPT-SciSciNet huggingface dataset:
The effect of the core shell nanostructure arrays on PEM fuel cells a short review

Fuel cell technology is one of the solutions which can play an important role in the environmentally friendly with more efficient cleaner and quieter than traditional internal combustion engines Among the fuel cells types polymer electrolyte membrane fuel cells have many advantages regarding quick start up time less warm up time high power density and high efficiency There are still some limitations due to the cost of Pt based catalysts Platinum based catalysts are presently the most promising catalysts for Oxygen Reduction Reaction ORR in Fuel Cells Homogenously distributed Pt nanoparticles on carbon support Pt C nanoparticles are mostly using in conventional way to produce Fuel Cells Pt based electrocatalysts with higher activity and durability are needed for cost competitive PEM Fuel Cells It can be developed improved further by using Platinum based alloy thin film core shell nanostructures For this reason this article reviewed the significance and processing of such core shell structures The general information about Fuel Cells is given at the beginning of this review article Later type of the fuel cells along with more definition of the PEM Fuel Cells are described The Pt shell on Ni Cr Pd Ru and WC core nanorods increase the stability and durability and decrease the cost based on the published works This nanostructured design will significantly impact the fuel cell technology by improving catalysts Specifically by controlling size composition and surface area to volume ratios this review article describes the investigation of the core shell nanostructured array catalysts A few of the following examples of core shell structures and supported catalysts proved electrocatalytic oxygen reduction
Treatment of Digestive Disorders

The digestive system is made up of the hollow muscular organs, esophagus, stomach, small intestine, large intestine and rectum, through which food passes during the digestive process. There are also several accessory organs of the digestive system, the salivary glands, liver and gall-bladder, and pancreas; these supply digestive juices and digestive enzymes. The appendix, an organ with an uncertain function, also forms a part of the system.
Variants of FFT Algorithm and Their Implementations

In chapter 3, additive FFT algorithms were derived corresponding to the factorization of the transform size N into the product of two factors. Analogous algorithms will now be designed corresponding to transform sizes given as the product of three or more factors. In general, as the number of factors increases, the number of possible algorithms increases.
The Michigan computer-aided engineering network

Publisher Summary The College of Engineering at the University of Michigan has planned its computing environment around the total computing needs of the faculty, staff, and students. In planning to meet these needs, it developed a statement of purpose that is (1) provide an environment where computing resources are used as naturally as mathematics, (2) provide state-of-the art facilities comparable to the facilities that are available in high tech employment, (3) serve concurrently and comprehensively: research, instructional, administrative, and personal needs, (4) provide resources for all engineering disciplines, and (5) develop a hierarchical network of networks that involve several communications protocols supporting the workstations of several classes and providing complete nodal interconnection. The decision to make the statement of purpose was prompted by a number of facts, namely, dramatic increases in the cost/performance of hardware; it is also economically feasible to provide every student, staff, and faculty member almost unlimited access to an individual workstation and immense computing power.
Microhabitat selection by small mammals in a southern Appalachian fen in the USA

Little ecological information is available on small mammals inhabiting wetlands in the southern Appalachian mountains of the USA. These wetland systems are becoming rare features in southern landscapes due to human activities. We investigated the small mammal fauna and examined the microhabitat associations of the two most abundant species in a southern Appalachian fen. Four species of small mammals were captured: the meadow jumping mouse (Zapus hudsonius), short-tailed shrew ( Blarina brevicauda), white-footed mouse ( Peromyscus leucopus), and golden mouse ( Ochrotomys nuttalli). Peromyscus and Ochrotomys, which were caught in the largest numbers, preferred sites characterized by moderate herbaceous cover and substantial canopy closure. Peromyscus, however, selected areas with greater canopy closure and higher tree densities, suggesting that they are greater habitat specialists than Ochrotomys in this wetland community.
Bread and Butter or Bread and Roses? Experimental Evidence on Why Public Sector Employees Support Unions

Despite their decline, unions, and especially public unions, remain important associations. Yet we do not have a good understanding of why workers voluntarily support and join unions. We report on a field experiment conducted during a 2017 Iowa teachers union recertification election. We randomly assigned union members voting in the election to receive emails describing union benefits and measured effects on turnout effort (N=10,461). Union members were more likely to try to vote when reminded of the professional benefits — but not legal protections or political representation — their union offered. A follow-up survey identified the specific benefits that members most valued and why. In a context where union membership and support is voluntary, our findings emphasize the importance of selective professional benefits. Our results have broader implications for understanding the American labor movement and civic participation. They suggest that public-sector unions may face a tension between political activities and offering excludable workplace benefits.
Relationship of food insecurity to women's dietary outcomes: a systematic review

Context Food insecurity matters for women's nutrition and health. Objective This review sought to comprehensively evaluate how food insecurity relates to a full range of dietary outcomes (food groups, total energy, macronutrients, micronutrients, and overall dietary quality) among adult women living in Canada and the United States. Data sources Peer-reviewed databases (PubMed/MEDLINE, CINAHL, Scopus, Web of Science) and gray literature sources from 1995 to 2016 were searched. Data extraction Observational studies were used to calculate a percentage difference in dietary intake for food-insecure and food-secure groups. Results Of the 24 included studies, the majority found food-insecure women had lower food group frequencies (dairy, total fruits and vegetables, total grains, and meats/meat alternatives) and intakes of macro- and micronutrients relative to food-secure women. Methodological quality varied. Among high-quality studies, food insecurity was negatively associated with dairy, fruits and vegetables, grains, meats/meats alternatives, protein, total fat, calcium, iron, magnesium, vitamins A and C, and folate. Conclusions Results hold practical relevance for selecting nutritional targets in programs, particularly for nutrient-rich foods with iron and folate, which are more important for women's health.
Trajectories of pre- and postnatal co-use of cannabis and tobacco predict co-use and drug use disorders in adult offspring

Abstract Co-use of cannabis and tobacco is increasingly common among women and is associated with tobacco and cannabis dependence and poorer cessation outcomes. However, no study has examined maternal patterns of co-use over time, or the impact of maternal co-use on co-use and drug problems in adult offspring. Pregnant women (M age = 23, range = 18–42; 52% African American, 48% White) were asked about substance use during each trimester of pregnancy, and at 8 and 18 months, 3, 6, 10, 14, 16, and 22 years postpartum. We examined patterns of any maternal cigarette and cannabis use during pregnancy and the postpartum years. As young adults (M age = 22.8 years, range = 21–26), 603 offspring completed the Diagnostic Interview Schedule (DIS). Growth mixture modeling (GMM) was used to identify four maternal trajectories through 16 years postpartum: (1) no co-use (66%), (2) decreasing co-use (16%), (3) postpartum-only co-use (11%), and (4) chronic co-use (7%). Offspring whose mothers were in the decreasing co-use group (co-users primarily during prenatal and preschool periods) were more likely to be co-users than the offspring of non-co-users. Offspring whose mothers were chronic co-users of cigarettes and cannabis were more than twice as likely to have a drug use disorder than young adults whose mothers were not co-users. The results of this study highlight the heterogeneity in maternal co-use of tobacco and cannabis over time, with some women quitting during pregnancy but resuming co-use in the postpartum, and other women co-using during pregnancy but desisting co-use over time. Maternal trajectories of co-use were associated with inter-generational transfer of risk for substance use and dependence in adult offspring.
Demonstration of phase-assisted material decomposition with a Talbot-Lau interferometer using a single x-ray tube potential

We present a proof-of-principle demonstration of material decomposition using a single X-ray tube potential (38 kVp + 0.2 mm Sn, for an effective energy around 27 keV) with a Talbot-Lau grating-based phase-contrast computed tomography (CT) system. We show good material separation of water and fat and an accurate quantitative measurement of isopropyl alcohol. This method utilizes the distinctiveness of both components of the refractive index, δ and β, and is promising for separating soft tissue materials that have similar attenuation values such as water and fat.
A New Safe Harbor - Turning Drug Rebates into Discounts in Medicare Part D.

A New Safe Harbor A proposal to require drug companies to pass discounts directly to Medicare patients at the point of sale would fundamentally change the role of medication rebates in Part D — and...
Resistin induces breast cancer cells epithelial to mesenchymal transition (EMT) and stemness through both adenylyl cyclase-associated protein 1 (CAP1)-dependent and CAP1-independent mechanisms

Breast cancer incidence and metastasis in postmenopausal women are known to associate with obesity, but the molecular mechanisms behind this association are largely unknown. We investigated the effect of adipokine resistin on epithelial to mesenchymal transition (EMT) and stemness in breast cancer cells in vitro. Previous reports demonstrated that the inflammatory actions of resistin are mediated by the adenylyl cyclase-associated protein 1 (CAP1), which serves as its receptor. As a model for our study, we used MCF-7 and MDA-MB-231 breast cancer and MCF-10A breast epithelial cells. We showed that in MCF-7 cells resistin increases the migration of MCF-7 and MDA-MB-231 cells and induces the formation of cellular protrusions through reorganization of F-actin filaments. Resistin upregulated the expression of mesenchymal markers involved in EMT (SNAIL, SLUG, ZEB1, TWIST1, fibronectin, and vimentin), and downregulated those of epithelial markers (E-cadherin and claudin-1). Resistin also potentiated the nuclear translocation of SNAIL protein, indicating initiation of EMT reprogramming. We further induced EMT in non-carcinogenic breast epithelial MCF-10A cells demonstrating that the effects of resistin on EMT were not breast cancer cell specific. In order to assess whether resistin-induced EMT depends on CAP1, we used siRNA approach to silence CAP1 gene in MCF-7 cells. Results demonstrated that when CAP1 was silenced, the induction of SNAIL, ZEB1 and vimentin expression by resistin as well as SNAIL and ZEB1 nuclear translocation, were abolished. Additionally, CAP1 silencing resulted in a suppression of MCF-7 cells migration. We performed quantitative PCR array profiling the expression of 84 genes related to cancer stem cells (CSC), pluripotency and metastasis and selected a set of genes (ALDH1A1, ITGA4, LIN28B, SMO, KLF17, PTPRC, PROM1, SIRT1, and PECAM1) that were modulated by resistin. Further experiments demonstrated that the effect of resistin on the expression of some of these genes (PROM1, PTPRC, KLF17, SIRT1, and PECAM1) was also dependent on CAP1. Our results demonstrate that resistin promotes the metastatic potential of breast cancer cells by inducing EMT and stemness and some of these effects are mediated by CAP1.
S06.2 T. pallidum in vitro growth

For over a century, investigation of Treponema pallidum subsp. pallidum, the spiral-shaped bacterium that causes syphilis, was hindered by an inability to culture the organism in vitro. Recently, we reported long-term cultivation of this enigmatic organism using modifications of previously described mammalian cell co-culture. In vitro cultures of T. pallidum have now been maintained continuously for over 500 days, with full retention of multiplication rate, motility, structural integrity, and infectivity in a rabbit model. Genome sequencing of long-term in vitro cultured T. pallidum has revealed remarkable genetic stability, in that organisms from long-term in vitro culture had identical genome sequences and the same intrastrain heterogeneity observed in the original organisms used for inoculation. We have verified that replacement of Eagle’s MEM with CMRL 1066 as the basal medium was key to achieving long-term growth. Surprisingly, the reducing agent dithiothreitol (DTT) was not required for long-term multiplication in the tissue culture system. We have also examined the effects of the scale of culture, medium composition, and axenic vs. mammalian cell co-culture. Finally, we have utilized limiting dilution to generate clonal isolates of T. pallidum, an important first step in developing a system to genetically manipulate the bacterium. Further development of the T. pallidum in vitro culture system is likely to have far-reaching effects on many aspects of T. pallidum research, including studies of physiology, structure, genetics, gene regulation, antimicrobial susceptibility, pathogenesis, immune reactivity, and epidemiology. Disclosure No significant relationships.
The initial development and validation of the Racial Socialization Competency Scale: Quality and quantity.

Objectives The present study investigated the reliability and validity of the Racial Socialization Competency Scale (RaSCS). As posited by the Racial Encounter Coping Appraisal and Socialization Theory (RECAST), the RaSCS consists of 3 factors representing 3 novel dimensions of racial socialization competency present in families (e.g., stress, skills, and confidence). Method Responses to the RaSCS were collected from 361 self-identified Black and African American parents and primary caretakers across the United States. Results After factor analysis, three scales and 27 items were maintained. Evidence was consistently found for 2 subscales within the stress dimension, namely "Call to Action" and "General" racial socialization stressors. Dimensions were also related to their respectively hypothesized constructs, including overall stress, racial socialization frequency, and self-efficacy. Conclusions Future directions and recommendations on the measure's use, particularly in the context of interventions, are also discussed. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
Critical Rhetoric| Between Critical and Rhetoric: McKerrow’s Contribution to Contemporary Critical Practice

The introduction of critical rhetoric into the discourse of rhetorical studies constituted an important rupture with previous traditions within the field. Emerging out of a complex mix of political, philosophical, and academic trends, critical rhetoric produced significant shifts in the ways in which criticism was understood and practiced. The shifting and transformations did not, however, stop with the term’s introduction in 1989. In this essay, we trace the development of critical rhetoric through three additional phases: the Marxist challenge presented by Dana Cloud; the shift to vernacular discourse in the works of Kent Ono and John Sloop; and the recent development of participatory critical rhetoric in the works of Michael Middleton et al. We pursue this historical tracing to demonstrate the points of rupture and discontinuity by which critical rhetoric has been transformed.
The Risk, Reward, and Asset Allocation of Nonprofit Endowment Funds

We collect tax return data from all 311,222 public NPOs in the United States over the 2009-2017 period to study the asset allocation choices and investment returns of their endowment funds. One in nine public NPOs have endowment funds. The majority of funds allocate their assets conservatively to low-risk assets, and as a result, earn an average annual return of 5.3%. There is substantial heterogeneity in investment returns across funds. Large funds significantly outperform small funds across all return measures and nonprofit sectors. Endowments in NPO sectors devoted to public and societal benefit, the environment, and the arts are among the top performers. High returns among higher education endowments are explained by size, while hospital endowments significantly underperform. Higher investment returns are associated with better governance, more highly paid management, lower discretionary spending, and lower investment management fees. Lastly, when faced with volatile contributions, endowment funds hold more cash and invest more conservatively.
Societat : Barcelona'92, un punt de vista des de l'antropologia cultural

John MacAloon fa un repas dels Jocs de Barcelona'92 des de la perspectiva de l'antropologia cultural.
Platinum nanometal interconnection of copper–carbon nanotube hybrid electrical conductors

Abstract This study demonstrates the versatility of Joule heating driven chemical vapor deposition to deposit nanometal interconnections into porous CNT roving with application in the production of high electrical conductivity copper-carbon nanotube (Cu-CNT) hybrids. Modifications of vapor deposition parameters allow for deposited nanometal masses from less than 5% w/w to over 85% w/w and distributions that can be controlled towards either hot-spot site-specificity or overall uniformity. Depositions of copper, platinum, nickel, palladium, ruthenium, rhodium, and iridium are demonstrated from acetylacetonate precursors. In particular, platinum acetylacetonate [Pt(acac)2] deposits nanometal seeds that adhere tightly to the CNT roving, producing improvements in resistance and specific conductivity. The properties of the platinum deposition compared to the copper deposition motivate an investigation into its use as an interfacial layer for Cu-CNT hybrids. CNT conductors with ∼30% w/w platinum are electroplated with copper, densified, and annealed to produce Cu-CNT hybrid conductors with specific conductivities as high as 5772 S m2/kg and TCR (from 300 to 600 K) as low as 3.12 × 10−3 K−1, indicating good interconnection of the metal and CNT portions. Room temperature conductivities of 29.8 MS/m are achieved, comparable to metallic conductors. Thus, Pt(acac)2 seeded Cu-CNT hybrids offer abundant promise in high conductivity applications.
Characteristics and Outcomes of Patients With Takotsubo Syndrome: Incremental Prognostic Value of Baseline Left Ventricular Systolic Function.

Background We sought to determine (1) long‐term outcomes in patients presenting with documented Takotsubo syndrome (TS), (2) whether left ventricular global longitudinal strain (LV‐GLS) provides in...
Characterization of a dual-mode horn for submillimeter wavelengths

A simple dual-mode conical horn has been developed and tested at 0.5 mm, 1.4 mm, 3.1 mm, and 34.2 mm. The horn has nearly equal beam shape in the E and H plane far field patterns with a 3dB half angle of 6°. At 34.2 mm the waveguide reflection loss and the phase center have been determined.
Selective Chronic Recording in the Peripheral Nervous System

Reliable interfacing with the peripheral nervous system has been and still remains a difficult problem to solve. Yet the ability to obtain signals from peripheral nerves would have significant benefits such as detection of motor intent in patients with amputation. Similarly decoding signals from the autonomic nervous system would allow continuous monitoring of organ function.
Scaffolding Multimodal Composition With Emergent Bilingual Students

Digital multimodal composition offers opportunities for emergent bilingual (EB) students to orchestrate semiotic resources in ways that develop their identities, strengthen their understandings of ...
Collaboration with China in social work education: experiences, suggestions and implications

The theme of this special issue is Global Collaboration with China in Social Work Education. The goals of this special issue are (1) to increase our understanding of the expansion of social work ed...
For Translation: Virginia Woolf, J. M. Coetzee, and Transnational Comparison

he transnational legacy of literary modernism typically begins with idiom. 1 Early twentieth-century novelists, from James Joyce and Virginia Woolf to Ernest Hemingway and Zora Neale Hurston, replaced the heroic lexicons of patriotism and imperial confidence with explicit language and the syncretic vocabularies of cosmopolitanism and regionalism. Among late twentieth-century novelists, a revival of idiomatic modernism is not far to seek: think of the “chutneyfication” of English in Salman Rushdie’s Midnight’s Children (1981), East, West (1994), and The Satanic Verses (1988); the use of syn tactic infelicity and translated speech in Kazuo Ishiguro’s A Pale View of Hills (1982) and An Artist of the Floating World (1986); and the play of accented voices in Irvine Welsh’s Train spotting (1993) and Zadie Smith’s White Teeth (2000). 2These works deploy the vernacular resources of English to explore the politics of language in an age of decolonization, multiculturalism, and global migration. They are indebted to modernist precursors because, like Ulysses (1922) and Mrs. Dalloway (1925), they suture narrative events to the sound and sense of Anglophone words. A modernist work such as Ulysses is difficult to translate, the novelist and translator Tim Parks has remarked, because it appears as “a thing made of lan guage. 3The same may be said of Midnight’s Children and A Pale View of Hills , whose “accented” English signals the transnational circulation of their narrators but does not itself circulate into other languages with ease. 4 This itinerary of modernist transnationalism appears persuasive if one looks forward from the major works of the early twentieth century, but it seems more limited from the perspec tive of the present. It doesn’t satisfactorily explain contemporary novels whose treatment of multilingualism and transnational collectivity eschews idiom but embraces other mod ernist strategies such as parataxis, recursive narration, and collage. And it misses altogeth er contemporary novels that resist homogeneous collectivities but nevertheless welcome, accept, or accommodate translation. What do translatable novels tell us about the afterlives of modernist transnationalism? To consider this question, we need to begin by distinguishing among modernist literary strategies, so that we can observe greater variety within modernism’s legacy. It will there fore be useful, as a preliminary gesture, to understand works of contemporary fiction as being modernist in some ways and non-modernist in others. Such an approach will allow
Molecular mechanisms and clinical significance of fibrinolysis

Fibrinolysis is the process of proteolytic digestion of fibrin aimed in vivo at dissolving clots or thrombi to restore the blood flow. In blood, the fibrinolytic system comprises a network of interrelated biochemical reactions that occur predominantly on the surface of fibrin fibers, the structural scaffold of hemostatic clots and obstructive thrombi. This review provides a brief description of the fibrinolytic system components and of the most important fibrinolytic reactions, including their modulation. The central enzyme in fibrinolysis is plasmin, a serine protease formed from its inactive precursor, plasminogen, upon the action of proteins and enzymes, whose formation and/or activation is triggered by various pathological stimuli. Plasmin cleaves a variety of substrates other than fibrin and therefore is involved in a number of biological processes other than hemostasis and thrombosis. There are several mechanisms moderating the activity of fibrinolytic enzymes that may become altered in various diseases. When the ratio of blood pro-and antifibrinolytic compounds is altered, hyper-or hypofibrinolysis might develop that causes and/or exacerbates hemorrhage or thrombosis, respectively. The paper contains an original pathogenic classification of fibrinolytic disorders and describes mechanisms of the primary and secondary hypo-and hyperfibrinolysis in various pathological conditions. Diagnosis of fibrinolytic defects builds on clinical symptoms along with defining the time of serum clots dissolving in vitro and serum levels of molecular markers. The principles of laboratory diagnostics of pathological fibrinolysis, based on the comprehension of the molecular mechanisms of normal and impaired fibrinolytic reactions, are reviewed. Treatment of pathological fibrinolysis implies the correction of either hyper-or hypofibrinolytic conditions and, therefore, is based on the administration of either antifibrinolytics (e-eminocaproic and tranexamic acids) or thrombolytics (mainly, plasminogen activators) in combination with other therapies against bleeding and thrombosis.
Using Bayesian networks to direct stochastic search in inductive logic programming

Stochastically searching the space of candidate clauses is an appealing way to scale up ILP to large datasets. We address an approach that uses a Bayesian network model to adaptively guide search in this space. We examine guiding search towards areas that previously performed well and towards areas that ILP has not yet thoroughly explored. We show improvement in area under the curve for recall-precision curves using these modifications.
Heat capacity of YBa2Cu3O7- delta crystals along the Hc2 line.

We report high-resolution ac heat-capacity measurements on ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ crystals near the critical temperature, several of which display untwinned regions comprising at least 50% of the sample volume. A \ensuremath{\lambda}-like anomaly is observed, indicative of an exceptionally short T=0 Ginzburg-Landau coherence length in this material. If the fluctuations are assumed to be Gaussian corrections to mean-field behavior, the data are best described by three-dimensional fluctuations of a two-component order parameter, with the underlying BCS step indicating strong-coupling behavior. However, a more complicated order parameter or a logarithmic (critical) divergence cannot be ruled out on statistical grounds. Application of a magnetic field B broadens the transition and reduces the amplitude of the anomaly with little or no apparent shift in the onset of superconductivity; the effects are more pronounced for B parallel to the c axis than for B in the ab plane. These results are not consistent with mean-field theory, but may be understood in the context of critical finite-size scaling. This approach exploits the well-known dimensional reduction for superconductors in a magnetic field.
Multi-band acoustic modem for the communications and navigation aid AUV

An acoustic communications system with the capability to operate at multiple data rates in two frequency bands has been designed and developed for use in 21-inch AUVs. The system is specifically designed around the 21-inch diameter Bluefin Robotics AUV, though it could be adapted to smaller vehicles (12-inch), or similar free-flooded vehicles. The system includes both high (25 kHz) and mid-frequency (3 kHz) modems and supports data rates from 80 bps to more than 5000 bps. Both of the modems utilize four-channel arrays to increase reliability. The high-frequency modem is also used to support multi-vehicle navigation via one-way travel time measurements using synchronized clocks on all of the vehicles in a work group
Potential mechanisms of interaction among secretagogues

Abstract We have considered three possible explanations for the ability of cimetidine to inhibit basal gastric acid secretion as well as acid secretion stimulated by histamine, gastrin, and cholinergic agents. Two of these explanations cannot account for existing experimental observations. The possibility that cimetidine is a noncompetitive inhibitor of gastric acid secretion can be excluded because cimetidine has been shown to be a competitive antagonist of the action of histamine on gastric acid secretion as well as other functions. The hypothesis that histamine is the final common mediator of acid secretion cannot account for these findings: (1) anticholinergic agents inhibit the action of gastrin and histamine on acid secretion, and (2) gastrin as well as acetylcholine potentiate the action of histamine on acid secretion. In contrast, all of the existing experimental observations can be explained by the hypothesis that cimetidine inhibits the direct action of histamine on acid secretion and inhibits the potentiating action of histamine on acid secretion stimulated by gastrin or acetylcholine. We have also examined potentiating interactions between pairs of pancreatic secretagogues and have shown how an anticholingergic agent can appear to inhibit the action of noncholinergic secretagogues by virtue of its ability to abolish the potentiating interaction between the secretagogue and a cholinergic agent. Finally, we have illustrated how the pattern of the response to two agents which potentiate each other may reflect characteristics of the response mechanism rather than the quantitative features of the interaction between the two agents.
Protein Quaternary Structure: Symmetry Patterns

Protein molecules can assemble into larger, multisubunit oligomers that possess unique quaternary structures and biological properties. The properties of the oligomeric protein can be quite different from those of the individual subunits. The noncovalent protein–protein interactions giving rise to oligomers often result in symmetric complexes containing identical monomers in identical environments. The symmetry properties of these complexes are described, in particular with respect to the types of subunit–subunit interactions giving rise to the oligomers. Because the symmetry of the macromolecular assemblies is based on the symmetric interactions between the subunits, understanding the symmetry provides further insight into the functioning of the oligomers. Specific examples presented include: dimers and heptamers with cyclic symmetry, tetrameric and octameric oligomers with dihedral symmetry, multienzyme complexes with tetrahedral and dodecahedral structures, and pilin helical oligomers. Key Concepts: Many proteins form large complexes made up of multiple copies of identical subunits. Analysis of the quaternary structures of protein complexes in terms of symmetry can determine how equivalent the subunits are, in function as well as structure. Subunits in dimeric proteins related by twofold rotation axes interact using the same functional groups on each subunit, that is, isologously. Protein complexes showing cyclic and helical symmetries have subunits that do not interact with the same functional groups on each subunit; they interact heterologously. Large protein complexes can take on the symmetries shown by the Platonic solids. Helical symmetry is found in large rod-like structures such as pili. Protein complexes showing point group symmetry are constructed using all of the available subunit–subunit binding surfaces and are ‘closed’ to addition of further subunits. Helical structures containing identical subunits have unoccupied binding surfaces at the termini of the helix that can bind additional subunits and grow into unlimited polymers. Keywords: quaternary structure; symmetry; viruses; multienzyme complexes; protein–protein interactions; protein oligomers
The neuroprotective potential of endoplasmic reticulum chaperones

Diseases of the nervous system are characterized by axon dysfunction, axon degeneration, and neuronal cell death. The roster of neurodegenerative diseases is striking in the selective vulnerability of the affected neuronal populations and the timing of the onset of disease manifestation and functional deficits. We are particularly fascinated by the extreme long term progression of many of these diseases prior to onset of significant functional loss and believe this reveals essential qualities of these diseases and offers considerable therapeutic opportunity. Though a complete mechanistic understanding of axon maintenance and neurodegeneration remains elusive, the primary process of neurodegeneration appears similar (e.g., Wallerian degeneration) across neuronal populations, as does caspase-dependent or -independent apoptotic cell death and likewise other forms of cell death (e.g., necrosis and necroptosis). Thus, it seems probable that the basic mechanisms of neuronal cell death and degeneration can be selectively manipulated through core cell processes, thereby preventing and/or halting the disease onset and progression.
Understanding Members’ Active Participation in Online Question-and-Answer Communities: A Theory and Empirical Analysis

AbstractCommunity-based question-and-answer (Q&A) websites have become increasingly popular in recent years as an alternative to general-purpose Web search engines for open-ended complex questions. Despite their unique contextual characteristics, only a handful of Q&A websites have been successful in sustaining members’ active participation that, unlike lurking, consists of not only posting questions but also answering others’ inquiries. Because the specific design of the information technology artifacts on Q&A websites can influence their level of success, studying leading Q&A communities such as Yahoo! Answers (YA) provides insights into more effective design mechanisms. We tested a goal-oriented action framework using data from 2,920 YA users, and found that active online participation is largely driven by artifacts (e.g., incentives), membership (e.g., levels of membership and tenure), and habit (e.g., past behavior). This study contributes to the information systems literature by showing that active ...
SU‐FF‐T‐385: Reproducibility of the Optical CT‐Based Polymer Gel Dosimetry

Purpose: To study the reproducibility of the reconstructed dose distributions from optical CT scanning of polymergel dosimeters with variation of time between irradiation and scanning using phantoms of the same and different geometry. Method and Materials: The commercial BANG®3 polymergels from the same batch were housed in cylindrical phantoms of 3 types: a) PET bottles of 15 cm diameter and 20 cm height; b) Barex cylinders of 17 cm diameter and 15 cm height; c) Acrylic cylinders of 25 cm diameter and 25 cm height. Four PET and Acrylic gel phantoms were irradiated with a 5 field IMRT and a 3DCRT once each. Six Barex cylinders were irradiated with the same IMRT and 3DCRT plans three times each. One additional Barex gel phantom was irradiated with a 6 cm × 6cm, 12 MeV electron field for calibration purpose. The gel phantoms were scanned using the OCTOPUS™ optical scanner one day after irradiation. One Barex phantom irradiated with IMRT fields was scanned 1 and 8 weeks later. All reconstructed images were calibrated using the dose response curve from the electron field irradiation. Root mean square of the pixel dose differences in a cylindrical region of 10 cm diameter and 10 cm height were compared for each pair of phantoms irradiated with the same plan. Results: The reconstructed dose distributions from scanning the same IMRTgel phantom 8 weeks apart change less than 1%. The root mean square dose difference among the 3 different kinds of phantoms irradiated with the IMRT and 3DCRT plans are all less than 3%. Conclusion: The optical CT‐based polymergeldosimetry is reproducible within the experimental uncertainty (3%) when different gel phantoms are irradiated and scanned at different time after irradiation. This work was supported by MGS research Inc. (Madison, CT; www.mgsresearch.com).
Prenatal alcohol exposure alters enkephalin levels, without affecting ethanol preference

Pregnant dams were pair-fed a liquid diet containing 35% ethanol derived calories or isocaloric sucrose during the last two trimesters of pregnancy. No differences were observed in adult ethanol preference between fetal alcohol exposed (FAE) animals and pair-fed controls. However, Met- and Leu-enkephalin levels were significantly elevated in globus pallidus of adult FAE animals. Pituitary levels were unaffected.
No words of their own

The Anthropology of Slavery: the Womb of Iron and Gold. CLAUDE MEILLASSOUX, translated by Alide Dasnois. London: The Athlone Press and Chicago: University of Chicago Press. 1991. 421pp.
Exaggerated [Ca2+]I Signaling and Alzheimer's Disease-Like Phenotypes of PS1M146V Mice are Attenuated by Decreasing Brain InsP3R-1 Protein Levels

Familial Alzheimer's disease (FAD) is linked to mutations in the presenilin (PS) homologs. FAD mutations have several cellular consequences, including exaggerated intracellular Ca2+ ([Ca2+]i) signaling - enhanced sensitivity to agonists of ER Ca2+ release and increased magnitudes of [Ca2+]i signals. Single channel recordings suggest exaggerated [Ca2+]i signaling is due to a gain-of-function interaction between FAD mutant PS and the inositol 1,4,5-trisphosphate receptor (InsP3R). However, the in vivo significance of the PS-InsP3R interaction to exaggerated [Ca2+]i signaling and the contribution of exaggerated [Ca2+]i signaling to the development of AD are unknown. If exaggerated [Ca2+]i signaling is InsP3R-dependent, we hypothesize that decreasing InsP3R protein expression will normalize [Ca2+]i signaling. Therefore, we crossed the Opisthotonus (Opt) mouse, deficient in InsP3R1 protein, to the PS1M146V knock-in (PS1KIN) AD mouse model to investigate the contribution of InsP3R-1-mediated [Ca2+]i release to exaggerated [Ca2+]i signaling, and the role of exaggerated [Ca2+]i signaling to the AD-like phenotypes of this mouse model. We observed that the Opt allele normalizes exaggerated [Ca2+]i release in vitro and ex vivo. Interestingly, in young (5wk) and mature (3 mth) PS1KIN mice we observed that the Opt allele normalized aberrantly activated hippocampal biochemical pathways and the enhancement of CA3-CA1 early long-term potentiation present in these mice - phenotypes that mirror the early hippocampal hyperactivity in patients that later develop AD. These findings indicate that FAD mutant PS-associated exaggerated [Ca2+]i signaling is InsP3R1-dependent and a early event in Alzheimer's disease.
Notes on calycophyllous Rubiaceae. Part I. Morphological comparisons of the genera Chimarrhis, Bathysa, and Calycophyllum, with new combinations and a new species, Chimarrhis gentryana

A comparison of some genera of the Condaminecae (Rubiaceae) with a few taxa of closely related tribes (Rondeletieae, Calycophylleae, and Cinchoneae) revealed that some species ofChimarrhis (Condamineeae s. 1.),Bathysa (Rondeletieae), andCalycophyllum (Calycophylleae) are often misassigned to genera. The taxonomic significance of calycophylls is discussed; the generic boundaries ofChimarrhis, Bathysa, andCalycophyllum are reevaluated; and their similarities and differences are discussed. As a result, a new calycophyllous species ofChimarrhis from the Amazon,C. gentryana, is described, two of its species are transferred toBathysa (B. Bathysoides, B. perijaensis), and one species ofBathysa (B. difformis) is reduced to synonymy underChimarrhis (C. turbinata).
Regulation of cardiomyocyte signaling by RGS proteins: Differential selectivity towards G proteins and susceptibility to regulation

Many signals that regulate cardiomyocyte growth, differentiation and function are mediated via heterotrimeric G proteins, which are under the control of RGS proteins (Regulators of G protein Signaling). Several RGS proteins are expressed in the heart, but so far little is known about their function and regulation. Using adenoviral gene transfer, we conducted the first comprehensive analysis of the capacity and selectivity of the major cardiac RGS proteins (RGS2-RGS5) to regulate central G protein-mediated signaling pathways in adult ventricular myocytes (AVM). All four RGS proteins potently inhibited Gq/11-mediated phospholipase C beta stimulation and cell growth (assessed in neonatal myocytes). Importantly, RGS2 selectively inhibited Gq/11 signaling, whereas RGS3, RGS4 and RGS5 had the capacity to regulate both Gq/11 and Gi/o signaling (carbachol-induced cAMP inhibition). Gs signaling was unaffected, and, contrary to reports in other cell lines, RGS2-RGS5 did not appear to regulate adenylate cyclase directly in AVM. Since RGS proteins can be highly regulated in their expression by many different stimuli, we also tested the hypothesis that RGS expression is subject to G protein-mediated regulation in AVM and determined the specificity with which enhanced G protein signaling alters endogenous RGS expression in AVM. RGS2 mRNA and protein were markedly but transiently up-regulated by enhanced Gq/11 signaling (alpha1-adrenergic stimulation or Galphaq* overexpression), possibly by a negative feedback mechanism. In contrast, the other negative regulators of Gq/11 signaling (RGS3-RGS5) were unchanged. Endogenous RGS2 (but not RGS3-RGS5) expression was also up-regulated in cells with enhanced AC signaling (beta-adrenergic or forskolin stimulation). Taken together, these findings suggest diverse roles of RGS proteins in regulating myocyte signaling. RGS2 emerged as the only selective and highly regulated inhibitor of Gq/11 signaling that could potentially become a promising target for ameliorating Gq/11-mediated signaling and growth.
The Influence of Hemispheric Dominance on Scores of the Myers-Briggs Type Indicator

For 75 medical students and 248 undergraduates (samples treated separately), principal components analysis (PCA) revealed that the TF and El scales of the Myers-Briggs Type Indicator (MBTI) each de...
A model for matrix cracking in short fiber composites

Abstract To model the crack-fiber interaction in the case of matrix cracking in short fiber composites, the plane problem of an elastic elliptical inclusion interacting with an arbitrarily oriented crack is solved, where the fiber is modeled as an elliptical inclusion. Complex potentials presented by Stagni and Lizzio (1983, J. Appl. Phys . A30 , 217–221) are used to obtain the Green's function for this problem. The problem is formulated in terms of systems of singular integral equations which are solved numerically. Some detailed results are given for various crack and fiber geometries and fiber and matrix material combinations.
Protein-Ligand Interactions as a Driving Force for a High-Enthalpy Two-State Transition in Glutamate Dehydrogenase: The Opposing Roles of Phosphate and Acetate Ions

Abstract It is known that the binding of the reduced coenzyme (NADPH) to bovine liver glutamate dehydrogenase is controlled by the presence of phosphate, acetate, and other anions as well as the pH of the medium. These effecters mediate this binding by lowering the p K (8.5) of an ionizable group on the enzyme, and this p K shift is linked to a high enthalpy E ⇌ E′ transition in the protein. In this study, we have measured enthalpy changes and proton transfer for enzyme-NADPH binding under a variety of combinations of phosphate, acetate, and hydrogen ion concentrations. Positive interactions are observed in the pairs acetate-NADPH and H + -phosphate, and negative interactions are seen in the pairs H + -NADPH, phosphate-NADPH, acetate-phosphate, and H + -acetate. We present a general model to account for all of these effects. This model incorporates a newly defined coenzyme binding subsite. The observed phenomena are interpreted in terms of the extent of loading of the specific anion-binding site on the enzyme that regulates the ionization of an enzyme group of p K 8.5. A proton is cooperatively shared with two phosphate groups at this site. Furthermore, we conclude that this cooperative trimolecular binding to the enzyme constitutes an allosteric driving force for the high enthalpy two-state transition observed in the ligand binding reactions of this enzyme.
Evolution in Structural Polymorphism of Pluronic F127 Poly(ethylene oxide)−Poly(propylene oxide) Block Copolymer in Ternary Systems with Water and Pharmaceutically Acceptable Organic Solvents: From “Glycols” to “Oils”†

The evolution in the self-assembly of an amphiphilic poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) (PEO-PPO-PEO) block copolymer in ternary systems with water and organic solvents of varying relative polarity is examined. The phase behavior and microstructure of two ternary systems consisting of Pluronic F127 (Poloxamer 407), water, and the pharmaceutically acceptable solvents propylene carbonate (4-methyl-1,3-dioxolan-2-one) or triacetin (glycerol triacetate) are presented. The microstructure of the lyotropic liquid crystalline phases formed and their characteristic length scales are determined from small-angle X-ray scattering (SAXS). The trends in the SAXS lattice spacing and the interfacial area per block copolymer molecule help establish the location of the solvents in the microstructure. The phase behavior of the two systems studied here is discussed in the context of ternary systems of Pluronic F127 with water and polar solvents (“glycols”, e.g., propylene glycol) or apolar organi...
Elastic radiation from a propagating phase boundary

Abstract The elastic effects which occur when a solid undergoes a phase change from a metastable to a stable structure are considered. In such a change, stored energy is released, and some of this energy may appear in elastic form. Equations describing the elastic effects of the process are derived from an examination of internal strain and an assumption of linearity for frequencies in the seismic range. According to concepts presented in this paper, a solid can be strained internally by the presence of dislocations (real internal strain), and also by possessing a potential to deform at every point through a change in crystal structure (frozen internal strain). Equations for elastic effects are derived by using these concepts, and they are solved for plane phase boundaries in steady motion. These results are valid only for times sufficiently short that the linear approximation still applies. The speed of boundary motion cannot be determined from macroscopic classical theory, but the equations have solutions that correspond to two different mechanisms of boundary propagation. The first occurs if a stress pulse is able to induce the transformation. The plane phase boundary then propagates at the speed of sound, with a growing elastic wave tied to it, using up some of the energy released in the transformation. The second propagation mechanism occurs when externally applied stress exerts a force on the real strain field associated with the phase boundary. In this case, the speed of propagation is different from the sound velocity, but the process again involves an increase in elastic energy at the boundary due to the release of internal strain under phase transition. The amount of internal strain release depends on the thermodynamic nature of the process. If the reaction is sudden, strain release is small, and the transformation essentially diffusionless, the initial process is considered to occur at constant entropy. If the reaction continues, it becomes non-linear and the entropy is expected to increase. The non-linear problem is not treated in this paper. An estimate of energy release for the linear problem is given for the purpose of considering the propagating phase boundary as a possible earthquake source mechanism.