cssi/SciSciGPT-SciSciNet huggingface dataset:
Vibrational relaxation dynamics in layered perovskite quantum wells

Organic-inorganic layered perovskites, or Ruddlesden-Popper perovskites, are two-dimensional quantum wells with layers of lead-halide octahedra stacked between organic ligand barriers. The combination of their dielectric confinement and ionic sublattice results in excitonic excitations with substantial binding energies that are strongly coupled to the surrounding soft, polar lattice. However, the ligand environment in layered perovskites can significantly alter their optical properties due to the complex dynamic disorder of the soft perovskite lattice. Here, we infer dynamic disorder through phonon dephasing lifetimes initiated by resonant impulsive stimulated Raman photoexcitation followed by transient absorption probing for a variety of ligand substitutions. We demonstrate that vibrational relaxation in layered perovskite formed from flexible alkyl-amines as organic barriers is fast and relatively independent of the lattice temperature. Relaxation in layered perovskites spaced by aromatic amines is slower, although still fast relative to bulk inorganic lead bromide lattices, with a rate that is temperature dependent. Using molecular dynamics simulations, we explain the fast rates of relaxation by quantifying the large anharmonic coupling of the optical modes with the ligand layers and rationalize the temperature independence due to their amorphous packing. This work provides a molecular and time-domain depiction of the relaxation of nascent optical excitations and opens opportunities to understand how they couple to the complex layered perovskite lattice, elucidating design principles for optoelectronic devices.
Untransit: Remote Work and the Transformation of Local Land Use Law

Remote work is poised to transform land use law by untethering labor from centralized workplaces and blurring the boundaries between work and home. Traditionally, land use law and local governments have focused on separating work from home through the conduit of transit. The division of work from home in land use law and accompanying transit mindset have stunted the local role in remote work—or untransit. This Article argues that land use law should shift from (at best) tolerating work from home toward experimenting with policies that support and promote it. The local level is a productive ground for such experimentation. Differing local approaches respond to variability in the prevalence, benefits, and costs of remote work and uncertainty about its effects. The Article proposes a number of remote work policies that localities may consider. Most critically, expanding the local role in internet connectivity and boosting cybersecurity services will facilitate remote work for a broad range of workers and job seekers. The Article also suggests and considers other local policies, including incentive zoning for private work centers or remote work-friendly businesses, public provision of work spaces, financial relocation incentives for remote workers, land use planning for remote work needs, and default zoning rules that allow working from home.
Household Composition, Income, and Body Mass Index Among Adults by Race/Ethnicity and Sex

Disparities in obesity highlight the need for an examination of determinants that may be uniquely experienced by race and sex. An understudied factor is household composition with the potential for variation in its obesogenic impacts. This study examines the association between household composition and body mass index (BMI) among Black, Hispanic, and White adults and determines whether income moderates these associations. Using cross-sectional data from the 2011–2018 National Health and Nutrition Examination Survey, the number of children and adults aged ≥ 60 years in the household were reported among non-Hispanic Black and White adults as well as Hispanic adults aged 20–59 years old. Multivariable linear regressions were used to assess the associations between household composition and BMI with income as a potential moderator. Having multiple school-aged children was associated with higher BMI (β = 1.34, standard error (s.e.) = 0.50) among Hispanic men, while having older adults in the household was associated with lower BMI among Black women (β = − 3.21, s.e. = 1.42). Income moderated the associations between household composition and BMI among Black women and men. There were no associations between household composition and BMI in White women or men. Future studies should further explicate the mechanisms of household composition that uniquely impact obesity outcomes among Black women and men by income. Efforts to address higher BMI among those with more young children in the household should target Hispanic men.
Short and Long-term Outcomes Among High-Volume vs Low-Volume Esophagectomy Surgeons at a High-Volume Center.

To determine associations between surgeon volume and esophagectomy outcomes at a high-volume institution. All esophagectomies for esophageal cancer at our institution from August 2005 to August 2019 were reviewed. Cases were divided by surgeon into low,
Induction of Labor with Prostaglandins

The earliest reported observations of the biological activity of prostaglandins were those of Kurzrok and Lieb in 1930. They found that the effect of human semen on the motility of isolated nonpregnant uterine strips was influenced by the reproductive history of the patients. Semen relaxed strips from patients with previous successful pregnancy, and stimulated those from women with a history of sterility. Many subsequent studies revealed that the normal response of nonpregnant uterine strips to human seminal fluid is relaxation. Bergstrom and Sjovall (1957, 1960) were the first to isolate pure crystalline prostaglandins E1 and E2 from sheep vesicular glands. These and other workers (Bergstrom and Samuelsson, 1962; Bygdeman et al., 1966; Bygdeman and Samuelsson, 1966; Hamberg and Samuelsson, 1965; Samuelsson, 1963a, b) soon identified 13 different prostaglandins in human seminal fluid. In 1964, Bygdeman reported that isolated strips of nonpregnant uterus responded to PGE compounds by relaxation. In contrast, most strips from pregnant uteri were stimulated by PGEs and both nonpregnant and pregnant strips were stimulated by PGFs. Sandberg et al. (1964) reported that the inhibitory effect of PGEs on nonpregnant myometrium in vitro was most pronounced on strips from the isthmus area, in contrast to those from the corpus.
U.S. Government Electronic Information Resources: A Start-up Kit for Small and Medium-Sized Libraries

he U.S. Government is the largest producer of information in the world. Through its agencies it creates, gathers, and produces information on topics from the arts to the sciences and for all types of library users – children to senior citizens. Since 1858 the Federal Depository Library Program (F.D.L.P.) has been responsible for collecting, organizing, maintaining, preserving, and providing information from the federal government. Congressionally-designated libraries (up to two per congressional district) receive selected classes of government resources at no cost, and in return are obligated to provide open and free access to this material. These include some of the most useful reference sources at the information desk – the Occupational Outlook Handbook, Statistical Abstract of the United States, and the World Factbook. While depository libraries receive these items free, non-depository libraries have had to purchase these materials from the Government Printing Office (G.P.O.) or a repackaged version from a commercial publisher.
Case-Based Reasoning

The ability to generate a quick and accurate quotation brings a significant advantage to mass-customized production companies. Cost estimation is essentially a process that attempts to predict the final cost of a product, even though not all of the manufacturing parameters and conditions are known when the cost estimation is prepared. This chapter presents a case-based reasoning methodology for rapid and accurate estimation of cost of mass-customized products. Unlike existing parametric cost estimation techniques that compute an estimate based on a mathematical relationship between product specification and cost, this approach uses case-based reasoning to model the relationship between product configuration, resources requirement, and costs. Empirical results show that this approach produces reasonably accurate quotes. Thus, we contend that case-based reasoning approach hold a good promise for providing rapid and effective response to customers’ request for quotation.
Chapter 19 Future of the Antiphospholipid Syndrome

Abstract Although rapid progress has been made in our understanding of antiphospholipid antibodies (aPL) and their clinical associations, many issues are unresolved. In the coming years it is anticipated that significant advances will be made in several key areas. Laboratory research will further elucidate the mechanisms by which aPL are produced and how these antibodies contribute to hypercoagulability and pregnancy loss. Clinical research will clarify areas of uncertainty regarding risk assessment (e.g., how to interpret antibody titers that fluctuate over time) and optimal treatment (e.g. the optimal intensity and duration of warfarin anticoagulation). New, potentially safer therapeutic approaches will be evaluated, including antiplatelet drugs, novel anticoagulant agents (such as direct inhibitors of thrombin and factor Xa), and several promising immunomodulatory and anti-inflammatory strategies. Importantly, better educational resources and advocacy efforts will increase awareness of the antiphospholipid syndrome and benefit patients and their families.
Interaction of structurally diverse HSPs with ligand binding domains of CD91 (APP2P.110)

Select members of the Heat Shock Proteins (HSPs) are molecular chaperones, carrying diverse cargo including nucleotides, lipids, misfolded proteins and peptides. Immunization of mice or humans with HSPs leads to priming of T cell responses specific for the peptide antigens that they chaperone. HSPs, with the chaperoned peptides, in the extracellular environment have been shown to associate with the cell surface receptor CD91 expressed on antigen presenting cells (APCs). CD91 on APCs allow for endocytosis of HSP-peptide complexes and cross-presentation. Recently, we discovered that the same receptor CD91 acts as a signaling receptor for HSPs. HSPs were shown to cause the phosphorylation of the cytoplasmic tail of CD91, and thereby dictate the release of cytokines in a CD91-dependent manner. In this study, we aim to identify the domains on CD91 that are necessary for HSP binding. CD91 is expressed as a single polypeptide chain in the ER that is cleaved into the extracellular 515 kDa α-chain, included four ligand-binding domains, and the 85 kDa β-chain. By creating mini-gene constructs representing the ligand binding domains of CD91, the association of each HSP with each construct can be examined. The completion of this study will explain how the structurally diverse HSPs bind to a single receptor, necessary for priming immune responses.
Binary Reachability Analysis of Pushdown Timed Automata with Dense Clocks

We consider pushdown timed automata (PTAs) that are timed automata (with dense clocks) augmented with a pushdown stack. A configuration of a PTA includes a control state, dense clock values and a stack word. By using the pattern technique, we give a decidable characterization of the binary reachability (i.e., the set of all pairs of configurations such that one can reach the other) of a PTA. Since a timed automaton can be treated as a PTA without the pushdown stack, we can show that the binary reachability of a timed automaton is definable in the additive theory of reals and integers. The results can be used to verify a class of properties containing linear relations over both dense variables and unbounded discrete variables. The properties previously could not be verified using the classic region technique nor expressed by timed temporal logics for timed automata and CTL* for pushdown systems.
Business Groups, Political Action, and Republican Party Development

Connections between political parties and key economic interests are regularly asserted – labor and the Democratic Party, business and the Republicans. In organizational terms, support from labor unions is accorded a prominent role in understanding Democratic party development – lessening the need for a strong formal structure. The apparent absence of such support from business interest groups in the Republican case, however, remains under-explored.In this paper, I suggest that the lessons of business involvement in the electoral realm in the 1930s, ambiguities in the party positions on their issues of concern over the course of the next two decades, and an ideological vision based on individual action, constrained the ability of business groups to participate actively in the electoral realm, and to channel that support toward the Republican Party. This hesitation to embrace political action left the Republican party without a comparable source of outside support in comparison to the Democrats, providing a further reason for the noted Republican emphasis on internal party development since the 1950s.
Healthymagination at GE Healthcare Systems

Jeff Immelt, the CEO of GE, introduced a new innovation strategy named "healthymagination" in Spring 2009. With cost, quality, and access as its three pillars, healthymagination ensures a strong focus for new product introduction efforts all around GE. But will this focus enable GE to achieve and maintain market leadership across a healthcare market that is being buffeted by strong currents, including cost pressures, changes in chronic disease patterns, and rationalization of buyer behavior? Moreover, healthcare spending is also increasing in emerging economies, which could provide a strong growth engine for the future. Tom Gentile, the CEO of GE Healthcare Systems (GEHS), a key player in the Medical Imaging market, wonders how the innovation strategy might respond to these changes. GE has historically been a technology leader, selling the most advanced equipment to a variety of medical establishments. Will a complete shift to healthymagination allow GE to demonstrate strong organic growth through innovation, as Immelt had charged executives at GE?Learning Objective: The purpose of the case is to enable discussion on how contextual changes in technology as well as customer behavior, combined with macro-trends, require a constant reassessment of a broad innovation strategy. Such a strategy has to work, not for one product at a time, but must be developed with an eye to developing product portfolios for the future. These changes might require companies to move from technology-leadership to market-leadership. How should managers think about strategies that are flexible to meet the needs of multiple product lines, multiple geographic markets, and different customer segments, but also be focused enough? This case has been taught in the Marketing core at Harvard Business School, as part of a module focusing on "Growing and Sustaining Value." It would also fit well in elective courses on Innovation, Technology Strategy, New Product Development, or High-Technology Marketing.
The Decision to Tell

Abstract This paper examines the factors which affect the decision by gay men to disclose their sexual orientation to parents, siblings, friends, at school, at the workplace, and in their neighborhoods. The findings indicate that the generation that grew up before Stonewall remains more closeted in most settings than members of the younger generations. The gay individual's level of religiosity was not found to be associated with disclosure in most settings, and parental religiosity affected only disclosure by the youngest generation.
Prenatal Origins of Parent-Young Interactions in Birds: A Naturalistic Approach

Publisher Summary This chapter presents qualitative and quantitative data on the incubation behavior of wild birds, with special reference to gulls. The chapter focuses on auditory modality and other types of stimulation occurring in association with rising and resettling on the eggs. The chapter describes an experiment that was designed to discover whether and how laughing gull embryos would respond to certain parental calls to which they are naturally exposed during incubation. It was found that one such call—crooning—enhances aspects of embryonic motility. Another call—kow—appears to have depressing effects as early as day 15. Another experiment showed that late prenatal experience of parental calls—crooning—bears on their effectiveness in eliciting feeding responses in neonatal gull chicks.
Excitotoxic degeneration is initiated at non-random sites in cultured rat cerebellar neurons.

Prolonged stimulation of cultured cerebellar neurons by kainic acid (KA) leads to death of neurons first evident from the swelling of soma and neurites. Stimulation is accompanied by increases in [Ca2+]i and [Na+]i as monitored using digital imaging microfluorimetry. “Blebs” tended to form on neurites with the highest increases in [Ca2+]i. Points of Ca2+ entry into neurites via glutamate-receptor-gated channels predicted where approximately 80% of blebs would form tens of minutes later. These sites were close to neurite intersections where there was a high likelihood of synaptic contacts and were enriched in mitochondria as revealed by rhodamine 123 staining. Ca2+, but not Na+ entry, produced a loss of mitochondrial potential. Prolonged KA, but not 50K, applications could fully dissipate the neuronal Na+ gradient. Recovery of resting [Na+]i was delayed by Ca2+ loading. We propose that blebs form at certain synaptic regions due to localized ionic fluxes and local Ca2+ overloading. Increased [Ca2+]i may hamper restoration of normal [Na+]i permitting local osmotic swelling as well as activation of Ca(2+)-dependent enzymes and other processes. Na+ may slow, block, or reverse Na/Ca exchange and enhance swelling. These conditions could not be reproduced by global changes in ion concentrations produced by Ca2+ or Na+ ionophores. The earliest stages of excitotoxicity thus appear to be manifestations of localized disruptions of ionic homeostasis mediated by Ca2+ overload and Na+ influx.
Metamorphic equilibria in the siliceous dolomite system: 6 kbar experimental data and geologic implications

Hydrothermal experiments with H2O-CO2 fluids at Pfluid = 6 kbar yielded the following quilibrium conditions for reactions important in metamorphosed siliceous dolomites (T = °C; X = Xco2): (3) dolomite + 2 quartz = diopside + 2 CO2T = 620 ± 8X = 0.73 ± 0.03 (5) 5 dolomite + 8 quartz + H2O = tremolite + 3 calcite + 7 CO2T = 600 ± 5 550 ±5 540±5 500±5X = 0.66 ± 0.03 0.21 ± 0.03 0.21 ± 0.04 0.06 ± 0.02 (7) 3 dolomite + 4 quartz + H2O = talc + 3 calcite + 3 CO2T = 550±5 500±5 450 ±5X = 0.25 ± 0.05 0.07 ± 0.02 0.03 ± 0.02 (8) 2 dolomite + talc + 4 quartz = tremolite + 4 CO2T = 550 ± 5 540 ±5 500 ± 5X = 0.22 ± 0.03 0.21 ± 0.02 0.06 ± 0.02 A thermodynamically self-consistent 6 kbar T-XCO2, topology results by extrapolating equilibria from experimental brackets using a modified Redlich-Kwong equation for activities in H2O-CO2 mixtures. This topology restricts the assemblage talc + calcite to a narrow stability band in T-XCO2 space at XCO2 < 0.55 and T < 590°C. Accordingly, the occurrence of talc + calcite in pure siliceous dolomites metamorphosed at Pfluid = 6 kbar implies correspondingly water-rich fluids.
Fluorescently detectable magnetic resonance imaging agents.

This report describes the synthesis, characterization, and in vivo testing of several bifunctional contrast-enhancing agents for optical and magnetic resonance imaging (MRI) of experimental animals. These new agents integrate the advantages of both techniques since they can be visualized simultaneously by light and MRI microscopy. Employing this strategy allows the same biological structures of a specimen to be studied at dramatically different resolutions and depths. The complexes possess a metal chelator for binding a paramagnetic ion, gadolinium (Gd3+), and a covalently attached fluorescent dye. The first class of complexes are low-molecular weight species that are composed of the macrocyclic tetraamine 1,4,7,10-tetraazacyclododecane-N,N,N',N"-tetraacetic acid (DOTA) as the metal-chelating ligand coupled to tetramethylrhodamine. The second class of MRI-enhancing agents are composed of high-molecular weight polymers that are membrane impermeable and once injected into a cell or cells are trapped inside. These complexes possess multiple copies of both the metal−chelator−diethylenetriaminepentaacetic acid (DTPA) and the tetramethylrhodamine attached to a macromolecular framework of either poly(d-lysine) (pdl) or dextran. Images acquired of single cells after injection with these bifunctional agents enabled us to follow the relative motions and reorganizations of different cell layers during amphibian gastrulation and neurulation in Xenopus laevis embryos.
The Maximum Principle for Control Systems Described by Linear Parabolic Equations

We prove a version of the maximum principle for linear parabolic distributed parameter systems that avoids some of the usual smoothness assumptions on the target.
The Conformational Switch from the Factor X Zymogen to Protease State Mediates Exosite Expression and Prothrombinase Assembly

Zymogens of the chymotrypsin-like serine protease family are converted to the protease state following insertion of a newly formed, highly conserved N terminus. This transition is accompanied by active site formation and ordering of several surface loops in the catalytic domain. Here we show that disruption of this transition in factor X through mutagenesis (FXaI16L and FXaV17A) not only alters active site function, but also significantly impairs Na+ and factor Va binding. Active site binding was improved in the presence of high NaCl or with saturating amounts of factor Va membranes, suggesting that allosteric linkage exists between these sites. In line with this, irreversible stabilization of FXaI16L with Glu-Gly-Arg-chloromethyl ketone fully rescued FVa binding. Furthermore, the Km for prothrombin conversion with the factor Xa variants assembled into prothrombinase was unaltered, whereas the kcat was modestly reduced (3- to 4-fold). These findings show that intramolecular activation of factor X following the zymogen to protease transition not only drives catalytic site activation but also contributes to the formation of the Na+ and factor Va binding sites. This structural plasticity of the catalytic domain plays a key role in the regulation of exosite expression and prothrombinase assembly.
A formal rate law for slow double layer processes

Summary Formal rate laws previously derived for faradaic and non-faradaic heterogeneous electrode reactions are extended to other cases of slow relaxations confined to the solution-electrode interface. The electrode impedance is derived for the general case of a single slow process and a variety of simplified cases. Alternatives are offered for interpretations given of slow relaxations in published work.
Effect of hydrogen on the solidification velocity of highly undercooled nickel

Abstract The solidification velocity of undercooled nickel was measured in electromagnetic levitation under two different cooling gas environments, and residual gas concentrations were quantified in processed samples. Significant quantities of hydrogen were measured suggesting that hydrogen causes historically observed deviations from theoretically predicted solidification velocity at high undercoolings.
Experimentalidade: ciência, capital e poder no mundo dos ensaios clínicos

A terceirizacao e expatriacao de ensaios clinicos abriram um campo de atividade experimental sem precedentes. Este ensaio discute os mecanismos cientificos e regulatorios atraves dos quais um campo global de experimentalidade se configura. Ele mapeia a industria de ensaios clinicos e seu deslocamento para paises de media e baixa renda (especialmente o Leste Europeu e o Brasil). Enquanto o empreendimento de ensaios clinicos se adapta a normas regulatorias nacionais e internacionais, o reconhecimento de riscos prejudiciais a pacientes e populacoes e frequentemente adiado ou evitado. Este texto explora as brechas legais em relacao a como os beneficios e riscos desse empreendimento sao calculados, bem como as praticas emergentes de responsabilidade.
Just doing it: A visual ethnographic study of spectacular consumption behavior at Nike Town

This paper uses visual ethnographic methods, specifically participant observation and photography supplemented with interviews, in its investigation of the consumption of spectacle at Nike Town, Ch...
Myelodysplasia and deficiency of uridine diphosphate–galactose 4-epimerase

A 4-year-old girl known to have peripheral uridine diphosphate-galactose 4-epimerase deficiency was examined for bruising and thrombocytopenia. She had dysplastic peripheral blood and bone marrow changes, with a global platelet function defect. Uridine diphosphate-galactose-4-epimerase participates in a metabolic pathway that provides substrates for posttranslational glycosylation of secreted and membrane glycoproteins, including hematopoietic growth factors and their receptors; there may be a causal relationship between the two disorders.
The effects of ventromedial tegmental lesions on the biosynthesis of catecholamines in the striatum

Abstract Following ventromedial tegmental lesions in the brain stem of monkeys, tyrosine hydroxylase activity is significantly lower on the lesion side of the caudate nucleus and putamen. The in vivo formation of dopamine-C 14 from tyrosine-C 14 is impaired on the lesion side in these two regions of the CNS. The present findings support the idea that ventromedial tegmental lesions produce a degeneration of dopamine neurons in the ipsilateral caudate nucleus and putamen.
X-ray tomography verification for determining phase proportions in volcanic rocks

Traditionally, phase proportions in igneous rocks have been estimated by optical microscopy of thin-sectioned rocks to study the mineralogy and identify the proportions of equilibrium phases. For example, an in-depth investigation of basaltic igneous rocks recovered from the oceanic crust at Hess Deep, 110Km west of the Galapagos Islands used phase proportions estimated from petrography to verify results calculated from chemical analyses of the basaltic samples. Chemical analysis divided these samples into two groupings based on their relative FeO content. Those with low-FeO contents dominated the volcanic rock subset and those with higher-FeO contents dominated the intrusive subset. Calculations based on the chemical analyses suggested that plagioclase (an Fe-poor phase) had accumulated in magmas and resulted in the low-FeO group. Petrographic microscopy supported the calculations by verifying that plagioclase exist in relatively greater abundance in the low-FeO group compared to the high-FeO group. Optical microscopy requires the rock samples be sectioned and polished, and then each section is individually imaged in only two dimensions by the petrographic microscope. From these images modal percent of phases is determined for a threedimensional sample. Using nondestructive x-ray tomography and three-dimensional image analysis, we produce a more accurate assessment of phase proportions using an intact lava sample from the low-FeO group, and provide a threedimensional perspective on the relationship between phases in the rocks unavailable with standard petrographic microscopy techniques.
Prevention of prostate cancer through custom tailoring of chemopreventive regimen

One practical way to control cancer is through chemoprevention, which refers to the administration of synthetic or naturally occurring agents to block, reverse or delay the process of carcinogenesis. For a variety of reasons, the most important of which is human acceptance, for chemopreventive intervention naturally occurring diet-based agents are preferred over synthetic agents. For a long time, the prevailing mantra of cancer chemoprevention has been: "Find effective agents with acceptable or no toxicity and use them in preventing cancer in relatively healthy people or individuals at high risk for developing cancer". In pursuing this goal many naturally occurring phytochemicals capable of affording protection against carcinogenesis in preclinical settings in experimental animals have been described. However, clinical trials of single agents have yielded disappointing results. Since carcinogenesis is a multistage phenomenon in which many normal cellular pathways become aberrant, it is unlikely that one agent could prove effective in preventing cancer. This review underscores the need to build an armamentarium of naturally occurring chemopreventive substances that could prevent or slow down the development and progression of prostate cancer. Thus, the new effective approach for cancer prevention "building a customized mechanism-based chemoprevention cocktail of naturally occurring substances" is advocated.
Coinage Reform Under the Abbāsid Caliph Al-Ma¸Mūn1)

Etude de la politique monetaire menee sous le regne du calife Al-Ma'mūn : la reforme monetaire.Presentation par categorie des differentes pieces mises en circulation durant cette periode.
Configurational effects on conformational properties of cyclic nucleotides. I. Theoretical calculations of conformer preferences in α-nucleoside 3′,5′ cyclic monophosphates

A comparative study has been made of the configurational effects on the conformational properties of ..cap alpha..- and ..beta..-anomers of purine and pyrimidine nucleoside 3',5'-cyclic monophosphates and their 2'-arabino epimers. Correlations between orientation of the base and the 2'-hydroxyl group have been studied theoretically using the PCILO (Perturbative Configuration Interaction using Localized Orbitals) method. The effect of change in ribose puckering on the base-hydroxyl interaction has also been studied. The results show that steric repulsions and stabilizing effects of intramolecular hydrogen bonding between the base and the 2'-hydroxyl (OH) group are of major importance in determining conformations of ..cap alpha..-anomers and 2'-arabino-..beta..-epimers. For example, hydrogen bonding between the 2'-hydroxyl group and polar centers on the base ring is clearly implicated as a determinant of syn-anti preferences of the purine (adenine) or pyrimidine (uracil) bases in ..cap alpha..-nucleoside 3',5'-cyclic monophosphates. Moreover, barrier heights for interconversion between conformers are sensitive to ribose pucker and 2'-OH orientations. The results clearly show that a change in ribose-ring pucker plays an essential role in relieving repulsive interactions between the base and the 2'-hydroxyl group. Thus a C2'-exo-C3'-endo (/sub 2/T/sup 3/) pucker is favored for ..cap alpha..-anomers in contrast with the C4'-exo-C3'-endo (/sub 4/T/sup 3/) formmore » found in ..beta..-compounds. 54 references, 6 figures, 2 tables.« less
Hyperelastic modelling and parametric study of soft tissue embedded lump for MIS applications.

Background The existing MIS (minimally invasive surgery) instruments have caused severe restrictions to surgeons' tactile perception. In particular, palpation, which is an important technique in open surgery to assess the softness of the tissue and to detect any hidden lumps, is entirely absent in MIS procedures. Many researchers have developed smart endoscopic graspers to rectify different aspects of this problem. However, the effect of an anatomical feature in general and a lump in particular on the stress distribution on the sensitive surfaces of the smart MIS graspers still needs a lot of attention. Methods This paper investigates the effect of the important parameters of a lump on the stress distribution at the contact surface and subsequently the output of smart endoscopic graspers. Using experimental stress–strain compression test data, the material parameters required for the Mooney–Rivlin model were obtained and used in hyperelastic finite element analysis. Results The influence of size, depth and stiffness of the lump on the stress distribution at the contact surface are shown and discussed. The results of the non-linear finite element analysis were validated against experiments conducted on elastomeric material replicating soft tissue. Conclusions The consistency between finite element analysis results and experimental work validates the developed model, which is based on the hyperelastic formulation. The finite element analysis results obtained in this study are particularly useful for the development of an inverse model. The inverse model would extract fundamental information, such as size, depth and stiffness, of any hidden lump, using the outputs of the sensors. Copyright © 2008 John Wiley & Sons, Ltd.
Modern Day Moabites: The Bible and the Debate About Same-Sex Marriage

With the debate about same-sex marriage raging in the United States, this paper asks whether the canonical scriptures of Judaism and Christianity offer any justification for blessing same-sex unions. It looks to the ways that the Bible is used by proponents and opponents of same-sex marriage. It analyzes the hermeneutics of the religious left and the religious right, particularly as they grapple with the "clobber texts" of Lev. 18:22 and 20:13. It then turns to the biblical book of Ruth, which critic J. Hillis Miller describes as having "been alienated from itself, translated from itself" through new uses. The paper puts the book of Ruth to yet another new use/misprision, using it as a prooftext to support same-sex marriage. The book has already been upheld by lesbian readers of scripture because of the intimate relationship between the protagonists, Ruth and Naomi, but this paper "misreads" the text differently. Ruth describes how a marriage made between an Israelite and a Moabite brings about the line of King David, one of the most important figures in the Bible and the man from whose line the Messiah is expected to come. The biblical law, however, is unequivocal: Moabites are not permitted to enter into the community of Israel. Juxtaposing the levitical laws (ostensibly) prohibiting homosexuality with those banning Moabites from Israel, this paper argues that the religious left could hold up the book of Ruth as a biblical model for allowing marriage that seems explicitly forbidden by biblical law.
Visual serial search for Arabic and Roman numbers.

To discover whether there was a significant difference between visual serial search time for Arabic and Roman numbers, a repeated-measurements design was used with a group of 20 undergraduate female Ss. Results demonstrated the superiority of visual serial search for Arabic over Roman numbers across 10 30-sec. trials with 60-sec. intervening between equivalent tasks. This effect was thought to be a function of the heterogeneity of target and field components.
Classical and quantum superdiffusion in a time-dependent random potential.

We consider wandering of a nonrelativistic particle in a time-dependent random potential in d spatial dimensions. Its root-mean-square displacement from the initial position increases superdiffusively with time t as ${\mathit{t}}^{9/8}$ for dg1, and as ${\mathit{t}}^{6/5}$ in d=1. Its kinetic energy increases as ${\mathit{t}}^{1/2}$ for dg1, and as ${\mathit{t}}^{2/5}$ in d=1. These scaling behaviors hold for both the classical and the corresponding quantum-mechanical problem in continuous space-time and differ from those of lattice models.
Flow-independent drop deformation with zero surface tension

We derive exact solutions describing three-dimensional ellipsoidal drop deformation with zero surface tension in steady, planar linear flows. We apply the analysis to study the development of lamellar drop morphologies as observed in recent experiments.
Pharmaceutical research involving the homeless

Discussions of research involving vulnerable populations have left the homeless comparatively ignored. Participation by these subjects in drug studies has the potential to be upsetting, inconvenient, or unpleasant. Participation occasionally produces injury, health emergencies, and chronic health problems. Nonetheless, no ethical justification exists for the categorical exclusion of homeless persons from research. The appropriate framework for informed consent for these subjects of pharmaceutical research is not a single event of oral or written consent, but a multi-staged arrangement of disclosure, dialogue, and permission-giving. Payments and other rewards in biomedical research raise issues of whether it is ethical to offer inducements to the homeless in exchange for participation in drug studies. Such inducements can influence desperate persons who are seriously lacking in resources. The key is to strike a balance between a rate of payment high enough that it does not exploit subjects by underpayment and low enough that it does not create an irresistible inducement. This proposal does not underestimate the risks of research, which are often overestimated and need to be appraised in light of the relevant empirical literature.
Problems in Physically Based Simulations of Real-World Environments

For the design of buildings, advertising for the automotive industry, or interior design, physically-based simulations must be accurate representations of real-world environments. This heavily illustrated graphical talk identifies the unsolved research areas necessary to reach this goal and shows several compelling applications.
Study of Cu diffusion in Be using ion backscattering

The diffusion of Cu in single-crystal Be has been studied as a function of temperature, crystal orientation, and method of Cu introduction. Concentration-versus-depth profiles were obtained from the energy spectra of backscattered 2-MeV ${\mathrm{He}}^{+}$ and 2-MeV protons. The Cu was introduced by ion implantation at 100 keV or by vapor deposition. Reliable values of the dilute diffusion coefficient $D$ were obtained from the implanted samples when the Cu had diffused more than a factor of 2 beyond the initial implanted range ($\ensuremath{\simeq}900$ \AA{}), whereas anomalous diffusion rates were found over shorter distances. The vapor-deposited Cu films were not used to determine $D$ values, primarily because of substantial surface oxidation. However, the qualitative behavior of the three-component system Be-Cu-O was interpreted in terms of intermetallic compound formation and the heats of formation of the respective metal oxides. For example, whenever Be and Cu are present together, gettering of oxygen by Be is observed, and a surface layer of BeO is formed from which Cu is excluded. Also, the solubility of Cu in hcp Be at 750\ifmmode^\circ\else\textdegree\fi{}C was measured to be 5.5 \ifmmode\pm\else\textpm\fi{} 1.0 at.%, in good agreement with the published phase diagram. The coefficient $D$ was measured for Cu diffusion along both the $c$ and $a$ crystallographic axes of the hcp Be lattice, between 420 and 640\ifmmode^\circ\else\textdegree\fi{}C. There is a significant anisotropy, with $\frac{{D}_{c}}{{D}_{a}}=0.5\ifmmode\pm\else\textpm\fi{}0.1$ at 600\ifmmode^\circ\else\textdegree\fi{}C. These results merge smoothly with those obtained by Dupouy, Mathie, and Adda over the range 700-1000\ifmmode^\circ\else\textdegree\fi{}C, by the radioactive-tracer method. The combined data represent a variation in $D$ of a factor of $\ensuremath{\simeq}5\ifmmode\times\else\texttimes\fi{}{10}^{6}$ and permit an accurate determination of the activation energies. These are 2.00 \ifmmode\pm\else\textpm\fi{} 0.10 eV for the $a$ axis and 2.05 \ifmmode\pm\else\textpm\fi{} 0.10 eV for the $c$ axis. The LeClaire theory of heterovalent impurity diffusion was used to compare the Cu results with Be self-diffusion data of Dupouy, Mathie, and Adda. This theory was found to be inconsistent with the observed overall difference in activation energies between Cu and self-diffusion, and also with the observed anisotropy for Cu diffusion. In order to determine the sensitivity of the diffusion rate to radiation damage, a sample was bombarded with a flux of $\ensuremath{\simeq}3\ifmmode\times\else\texttimes\fi{}{10}^{13}$ ${\mathrm{Ne}}^{+}$/${\mathrm{cm}}^{2}$ sec during a 30-min anneal at 500\ifmmode^\circ\else\textdegree\fi{}C. The resulting rate of atomic displacement, $\ensuremath{\simeq}0.01$ dpa/sec for depths 5000 \AA{}, was not sufficient to produce an observable change in the diffusion rate.
Stress relaxation behavior of nanocluster-strengthened ferritic alloy at high temperatures

Abstract Stress relaxation behavior was investigated for the nanoclusters/dispersoids-strengthened steels including the nanostructured ferritic alloy 14YWT (SM10), oxide-dispersion strengthened (ODS) Eurofer97, and commercial ODS steel PM2000. The stress relaxation tests were carried out at high temperatures ranging from 600 to 1000 °C. Overall, the relaxation rates of 14YWT and ODS-Eurofer97 were lower than that of PM2000. To analyze the strain rate sensitivity of the alloys, the load drop–time curves were converted to the stress–strain rate curves. In the log–log plots of these curves, no significant change in slope was observed in the strain rate range of 2 × 10−5–1 × 10−3s−1. At 600 °C, 14YWT and ODS-Eurofer97 have similar activation values of ∼50b3 while PM2000 has ∼100b3. Above 700 °C, the differences of the activation energy among alloys become more noticeable with increasing temperature. The activation energies of the three alloys were derived and compared. The rate-controlling mechanisms in the stress relaxation of the three nanoclusters/dispersoids-hardened alloys include dislocation glide and climb, and further study is necessary to clarify detailed contributing mechanisms.
A pseudo-two-dimensional analysis of short channel MOSFETs

Abstract A new version of a pseudo-two dimensional analysis for the drain region of short channel MOSFETs is proposed. Second order effects such as mobility degradation, velocity saturation, and short channel effects are included in the analysis and the dependence on the processing parameters is taken into consideration. The model proposed in this paper guarantees the continuity of the output conductance and its derivative with respect to the drain voltage at the point of transition from the linear to the saturation region. The predictions of the model are confirmed by a comparison with the experimental data available in the literature.
Defect based spin mediation in δ-phase plutonium

We earlier reported the measured decrease of electrical resistivity during isochronal-annealing of ion irradiation damage that was accumulated at low-temperature (10 or 20K), and the temperature dependence of the resistance of defect-populations produced by low-temperature damage-accumulation and annealing in a stabilized {delta}-phase plutonium alloy, Pu(3.3 at%Ga)[1]. We noted that the temperature dependence of the resistance of defects resulting from low-temperature damage accumulation and subsequent annealing exhibits a -ln(T) temperature dependence suggestive of a Kondo impurity. A discussion of a possible ''structure-property'' effect, as it might relate to the nature of the {delta}-phase of Pu, is presented.
The study of the oxidation of nickel using resistivity measurements

Abstract Resistance measurements on thin nickel foils in argon-oxygen mixtures at 780°C provide previously unknown data on the initial oxidation kinetics of the Ni-O system. After the foils are annealed in dry hydrogen, resistance measurements upon introduction of argon-oxygen mixtures shown an initial parabolic increase, then decrease, then increase in resistance of the foils.
Terahertz Emission in Asymmetric Quantum Wells by Frequency Mixing of Midinfrared Waves

Generation of terahertz (THz), and sub-THz, coherent waves has been demonstrated at room temperature in GaAs-AlGaAs asymmetric quantum wells by mixing two CO2 laser beams. Two overlapping regimes were studied: the double resonance regime where three states are involved and the optical rectification which relies on two states only. The measured conversion efficiency of ~10-7 W-1 is in reasonable agreement with theoretical predictions. In addition, this technique of THz generation provides a model system to study the emission profile from an ensemble of radiating dipoles. For instance, backward emission and strong diffraction effects have been observed
Development of buffer layers on 30 mm wide textured metal substrates for REBCO coated conductors

Abstract We have been studying REBa 2 Cu 3 O x (RE: rare earth elements) coated conductors on clad-type substrates. We developed coated conductors on the 10 mm wide clad-type tape, and succeeded in obtaining the maximum critical current of 380 A/cm with the 2.0 μm thick GdBa 2 Cu 3 O x superconducting film. At present, we are trying to widen the tape width from 10 mm to 30 mm in order to increase production throughput. We report our recent progress on scaling-up of the buffer layers and their properties. The buffer layers consisted of three layers; CeO 2 as the seed layer, yttrium-stabilized zirconia (YSZ) as the diffusion barrier layer and CeO 2 as the lattice matching layer. They were grown by the RF-sputtering method and the electron beam evaporation technique (EB). EB deposition has possibility of higher throughput compared with the RF-sputtering. The intensity ratio of (2 0 0) to (2 0 0) + (1 1 1) for the lattice matching layer showed as high as 98%. The uniform properties of 40 m long and 30 mm wide substrates were successfully produced by all sputtering method. Additionally, the tape travel speed of the seed layer can be increased from 7 m/h (RF-sputtering deposition) to 10 m/h (EB deposition) on short sample (0.3 m long).
Dimensional modeling: Identification, classification, and evaluation of patterns

Software design is a complex activity. A successful designer requires knowledge and training in specific design techniques combined with practical experience. Designing a dimensional model embodies this challenge. This paper presents Dimensional Design Patterns (DDPs) and their application to the design of dimensional models. We describe a metamodel of the DDPs and show their integration into Kimball's dimensional modeling design process so they can be applied to design problems using a known practice. By providing a metamodel and a method for DDP use, we combine theory and a practical design technique with the goal of increasing the efficiency and effectiveness of the software designer. The experimental results show that the classroom use of DDPs increase the effectiveness by 25% and efficiency by 9% for students in designing dimensional models. This research shows that DDPs could be an effective tool not only for teaching a dimensional model in academia, but also for designing dimensional models in an industry setting.
Space-based augmentation for global navigation satellite systems

This paper describes space-based augmentation for global navigation satellite systems (GNSS). Space-based augmentations increase the accuracy and integrity of the GNSS, thereby enhancing users' safety. The corrections for ephemeris, ionospheric delay, and clocks are calculated from reference station measurements of GNSS data in wide-area master stations and broadcast via geostationary earth orbit (GEO) satellites. This paper discusses the clock models, satellite orbit determination, ionospheric delay estimation, multipath mitigation, and GEO uplink subsystem (GUS) as used in the Wide Area Augmentation System developed by the FAA.