cssi/SciSciGPT-SciSciNet huggingface dataset:
Cation and vacancy ordering in Li x CoO 2

Using a combination of first-principles total energies, a cluster expansion technique, and Monte Carlo simulations, we have studied the Li/Co ordering in ${\mathrm{LiCoO}}_{2}$ and Li-vacancy/Co ordering in the $\ensuremath{\square}{\mathrm{CoO}}_{2}$. We find: (i) A ground-state search of the space of substitutional cation configurations yields the CuPt structure as the lowest-energy state in the octahedral system ${\mathrm{LiCoO}}_{2}$ (and $\ensuremath{\square}{\mathrm{CoO}}_{2})$, in agreement with the experimentally observed phase. (ii) Finite-temperature calculations predict that the solid-state order-disorder transitions for ${\mathrm{LiCoO}}_{2}$ and $\ensuremath{\square}{\mathrm{CoO}}_{2}$ occur at temperatures $(\ensuremath{\sim}5100 \mathrm{K}$ and $\ensuremath{\sim}4400 \mathrm{K}$, respectively) much higher than melting, thus making these transitions experimentally inaccessible. (iii) The energy of the reaction ${E}_{\mathrm{tot}}(\ensuremath{\sigma},\mathrm{Li}\mathrm{Co}{\mathrm{O}}_{2})\ensuremath{-}{E}_{\mathrm{tot}}(\ensuremath{\sigma},\ensuremath{\square}\mathrm{Co}{\mathrm{O}}_{2})\ensuremath{-}{E}_{\mathrm{tot}}(\mathrm{L}\mathrm{i},\mathrm{}\mathrm{bcc})$ gives the average battery voltage $\overline{V}$ of a ${\mathrm{Li}}_{x}{\mathrm{CoO}}_{2}/\mathrm{Li}$ cell for the cathode in the structure $\ensuremath{\sigma}$. Searching the space of configurations $\ensuremath{\sigma}$ for large average voltages, we find that $\ensuremath{\sigma}=\mathrm{CuPt}$ [a monolayer $〈111〉$ superlattice] has a high voltage $(\overline{V}=3.78 \mathrm{V})$, but that this could be increased by cation randomization $(\overline{V}=3.99 \mathrm{V})$, by partial disordering $(\overline{V}=3.86 \mathrm{V})$, or by forming a two-layer ${\mathrm{Li}}_{2}{\mathrm{Co}}_{2}{\mathrm{O}}_{4}$ superlattice along $〈111〉$ $(\overline{V}=4.90 \mathrm{V})$.
Case Series of Transcutaneous Magnetic Stimulation for Ventricular Tachycardia Storm.

This case series describes outcomes for 5 patients with VT storm refractory to drug therapy treated with left stellate ganglion transcutaneous magnetic stimulation (TCMS) to reduce cardiac sympathetic input.
La animalidad a la luz de la Destruktion. Una lectura a partir (y a pesar) de Martin Heidegger

Proponemos en las siguientes paginas realizar una lectura critica y reflexiva en torno al seminario que Martin Heidegger impartio entre el ano 1929-1930 titulado Los conceptos fundamentales de la metafisica: Mundo, Finitud y Soledad. De lo que se tratara es de revisar los paragrafos en torno al problema de la animalidad, prestando especial atencion al momento de estructuracion de la diferencia con el hombre, en cuanto a este se le define como configurador de mundo (Weltbildend). Proponemos leer estos enigmaticos pasajes de Heidegger a la luz (Lichtung) del metodo planteado en Ser y tiempo, especificamente en el paragrafo seis que gira en torno a la Destruktion de la metafisica, al cual adscribimos como proyecto transversal de la obra de Heidegger. Pero habra en primera instancia que ver hasta que punto el analisis de la animalidad responde en Heidegger a una metodologia de la Destruktion. ?Sera quiza que la animalidad le presenta un limite a la Destruktion? ?Responde el analisis sobre el animal que lleva a cabo Heidegger a las exigencias de una destruccion de la metafisica tal y como se lo plantea en Ser y tiempo y otros textos? ?Hasta que punto Heidegger se desmarca de la axiomatica aristotelica metafisica que caracteriza la diferencia entre humano y animal en torno a la carencia de logos? ?Sera que Heidegger reproduce la diferencia humana/animal de la cual se pretende desmarcar y queda atrapado por los despojos de una comprension metafisica de occidente? Estas seran algunas de las preguntas que intentaremos pensar.
Group-level Fairness Maximization in Online Bipartite Matching.

We consider the allocation of limited resources to heterogeneous customers who arrive in an online fashion. We would like to allocate the resources "fairly", so that no group of customers is marginalized in terms of their overall service rate. We study whether this is possible to do so in an online fashion, and if so, what a good online allocation policy is. We model this problem using online bipartite matching under stationary arrivals, a fundamental model in the literature typically studied under the objective of maximizing the total number of customers served. We instead study the objective of maximizing the minimum service rate across all groups, and propose two notions of fairness: long-run and short-run. For these fairness objectives, we analyze how competitive online algorithms can be, in comparison to offline algorithms which know the sequence of demands in advance. For long-run fairness, we propose two online heuristics (Sampling and Pooling) which establish asymptotic optimality in different regimes (no specialized supplies, no rare demand types, or imbalanced supply/demand). By contrast, outside all of these regimes, we show that the competitive ratio of online algorithms is between 0.632 and 0.732. For short-run fairness, we show for complete bipartite graphs that the competitive ratio of online algorithms is between 0.863 and 0.942; we also derive a probabilistic rejection algorithm which is asymptotically optimal in the total demand. Depending on the overall scarcity of resources, either our Sampling or Pooling heuristics could be desirable. The most difficult situation for online allocation occurs when the total supply is just enough to serve the total demand. We simulate our algorithms on a public ride-hailing dataset, which both demonstrates the efficacy of our heuristics and validates our managerial insights.
PMU and Communication Infrastructure Restoration for Post-Attack Observability Recovery of Power Grids

This paper is concerned about recovering the observability of cyber-physical power grids after massive cyber attacks, which helps to achieve the cyber-physical resilience of the grids. For recovering the observability of the grid, the measurability of the Phasor Measurement Units (PMUs) and the connectivity of the communication network are needed to be restored. The PMU and communication infrastructure restorations are jointly formulated as a Mixed Integer Linear Programming (MILP) problem to minimize the observability loss of the grid over time after a cyber attack while considering the constraint of limited resources. The efficacy of the proposed optimal restoration strategy is verified by comparing with heuristic methods on the IEEE 57-bus system.
Effect of Pore Connectivity on the Behavior of Fluids Confined in Sub-Nanometer Pores: Ethane and CO2 Confined in ZSM-22.

The behavior of fluids under nano-confinement varies from that in bulk due to an interplay of several factors including pore connectivity. In this work, we use molecular dynamics simulations to study the behavior of two fluids—ethane and CO2 confined in ZSM-22, a zeolite with channel-like pores of diameter 0.55 nm isolated from each other. By comparing the behavior of the two fluids in ZSM-22 with that reported earlier in ZSM-5, a zeolite with pores of similar shape and size connected to each other via sinusoidal pores running perpendicular to them, we reveal the important role of pore connectivity. Further, by artificially imposing pore connectivity in ZSM-22 via inserting a 2-dimensional slab-like inter-crystalline space of thickness 0.5 nm, we also studied the effect of the dimensionality and geometry of pore connectivity. While the translational motion of both ethane and CO2 in ZSM-22 is suppressed as a result of connecting the pores by perpendicular quasi-one-dimensional pores of similar dimensions, the effect of connecting the pores by inserting the inter-crystalline space is different on the translational motion of the two fluids. For ethane, pores connected via inter-crystalline space facilitate translational motion but suppress rotational motion, whereas in the case of CO2, both types of motion are suppressed by pore connection due to the strong interaction of CO2 with the surface of the substrate.
Scaling of Polymer Solutions as a Quantitative Tool

Knowledge of interaction parameters and Kuhn length for a polymer/solvent pair is a foundation of polymer physics of synthetic and biological macromolecules. Here, we demonstrate how to obtain thes...
The Challenge of Incongruence in Richard de Fournival’s Bestiaire d’amour

This article considers Richard de Fournival’s Bestiaire d’amour, a French text from the second quarter of the thirteenth century. The Bestiaire’s narrator combines a love-lyric and a bestiary to ad...
Monitoring and estimation of late spring frost and its impact on winter wheat through multi-temporal GF-1 remotely sensed imagery

Frost events pose a threat to normal development of winter wheat and increase risk of production loss, even given the context of global warming. Henan province, which is the largest region of winter wheat cultivation in China, late spring frost damage has been one of the major meteorological catastrophes. For systematical and accurate monitoring and estimation of single-event frost damage of winter wheat, serial GF-1 remotely sensed imageries were collected during the winter wheat growth with field investigations and yield measurements in Yanjin county, Henan. Field investigation across Yanjin county based on five grades (normal growth, frost damage grade I to frost damage grade IV) defined by the agricultural indicators was conducted on 15 April and in which 133 ground samples were collected. Based on the investigation, the remotely sensed monitoring and estimation indicated that frost-affected areas accounted for 87.71% of the winter wheat planting area in the whole county. From frost damage I to frost damage IV, the frost-affected areas accounted for 55.52%, 15.79%, 2.90% and 16.32%, respectively. The frost-affected regions were distributed from northeast to southwest of the county, showing zonal distribution; and the severe frost damage regions showed scattered and irregular distribution. Based on the agronomic freezing indicators, it can be concluded that the frost damage III and frost damage IV would cause yield loss of the winter wheat. In an average year, the yield of winter wheat in Yanjin county was about 6750-9000 kg/ha. In 2018, the yield of winter wheat for normal growth and mild frost damage (grade I) was about 6750 kg/ha according to the field investigation; whereas, the yield of winter wheat was 3000-4500 kg/ha for slight frost damage (grade II) which did not form a disaster; and the yield of winter wheat was 600-2250 kg/ha for the severe frost damage (grade III and IV). According to the proportions of areas affected by the frost damage and the yield for different grades, the yield reduction of winter wheat caused by this late spring frost was about 24%-33% in 2018. Our findings reveal region-specific changes in the spring-frost risk that can inform decision-making in land management, forestry, agriculture, and insurance policy.
Adjusting Our Gaze: An Alternative Approach to Understanding Youth Radicalization

The article intends to provide an alternative perspective to examine the radicalization process. It rejects the causal paradigm in favor of a discursive approach that focuses on understanding psychological phenomena as revealed in discourse. My central argument is that a discursive approach offers greater explanatory power than is offered by the causal, reductionist approach that currently dominates the field. My article concludes by offering an interdisciplinary framework that uses discursive psychology as a mode of explanation to better understand how radicalization may occur at the individual level in various sociocultural contexts as a product of lived experience. The framework employs positioning theory as an analytic tool to examine discursive exchanges to provide insight into pathways to the development of radical belief systems among at-risk youth. This article is available in Journal of Strategic Security: http://scholarcommons.usf.edu/jss/vol8/iss1/1
Heparan Sulfate Degradation by Heparanases

Publisher Summary Interactions between the extracellular environment and the cell surface influence the growth and differentiation of cells as well as their organization into organs and tissues. Heparanases may remove all binding sites from proteoglycans by cleaving the heparan sulfate (HS chain) off the core protein or they may destroy specific binding sites when degrading the chain to shorter oligosaccharides. Apparent lack of heparanase 1 (Hpa1) expression in normal, non-lymphoid tissue raises the question of whether there are other heparanase enzymes. The increased expression is inhibited if the cells are exposed to the MEK inhibitor PD98059, providing evidence that induction of Hpa1 in T-cell activation may occur through MEK/ERK pathway. When Jurkat T cells are incubated with PMA to mimic T-cell activation, there is an increase in Hpa l expression. Four putative estrogen response elements in the 1700-base pair upstream of the transcription start site have been identified. Studies with carcinoma cell lines and tumor tissue also suggest that the expression of Hpa l may be regulated by the methylation state of the Hpa l promoter.
'Calling in the Troops': The Uneasy Relationship among Women's Rights, Human Rights, and Humanitarian Intervention

In this Article, I explore these changes in human rights law and discourse and suggest that feminists have participated in, even contributed to, the shift in discourse on both the right and the left. For the most part, for example, women’s rights advocates opposed neither the U.S. invasion of Afghanistan nor the use of women’s human rights to justify the invasion. Moreover, some of the women’s rights advocates who sought intervention in Bosnia and Herzegovina to respond to what they considered “genocidal rape” hoped to appeal to conservative hawks as well as liberal human rights advocates. Both of these appeals to or support for military force to respond to women’s rights in the 1990s participated in the development of an emerging consensus on humanitarian intervention.Part I uses the publications of the Harvard Human Rights Journal over the past twenty years to consider the developments within human rights scholarship and activism regarding women’s human rights and humanitarian intervention. Part II explores the consensus that is building around understanding humanitarian intervention as an “emerging norm,” and discusses how human rights and humanitarian non-governmental and intergovernmental organizations have increasingly embraced military intervention as the ultimate mechanism for enforcing human rights. Part III considers the international law surrounding that emerging norm, and what the norm might include. It examines the leading justifications for military intervention, noting the primacy of genocide in the hierarchy of justifications. Part IV returns to feminist debates of the 1990s over whether rape constituted genocide in Bosnia and Herzegovina, re-reading those debates in light of the emerging norm of humanitarian intervention. It then examines advocacy on behalf of intervention in Darfur as a recent example of the conflation of rape and genocide. Part V concludes by encouraging reconsideration of the potential consequences of increased calls for the use of force to protect human rights, not just for those involved in or directly affected by the military action, but for international law and policy more generally.
Altered reactivity to measles virus. Skin test reactivity and antibody response to measles virus antigens in recipients of killed measles virus vaccine.

Serum antibody response and skin test reactivity to intradermal measles antigens were studied in 3 groups of children who differed in their prior experience with natural measles or measles vaccines. Children who had received killed measles virus vaccine in the past had an almost universal skin test reactivity to killed measles antigen. Almost 2/3 of this group lacked serum antibody prior to intradermal testing; almost all responded to challenge with significant increase in serum antibody. In contrast, children who had measles previously or had been given live measles vaccine had no skin test reactivity and had detectable serum antibody. These data and others cited suggest that delayed hypersensitivity is responsible for the altered reactivity in some recipients of killed measles vaccine.
Identification and characterization of the products of six region III flagellar genes (flaAII.3 through flaQII) of Salmonella typhimurium.

A portion of flagellar region III of the Salmonella typhimurium genome has been cloned and shown to contain six genes: flaAII.3, flaAIII, flaS, flaR, flaQI, and flaQII. Of these, all but flaQI were known to exist from mutant studies; the former flaQ has been renamed flaQII. The genes were shown by minicell analysis to encode proteins with apparent molecular masses of 28, 48, 15, 46, 17, and 37 kilodaltons, respectively. The presence of a flagellar-gene-specific promoter in the vicinity of flaQI was established by testing expression of the plasmid-encoded tetracycline resistance gene in artificial constructions. In minicell preparations, the flaAII.3 and flaR products were found principally in the cytoplasmic fraction; the rest were found principally in the membrane fraction. A comparison between the homologous genes of S. typhimurium and Escherichia coli confirmed that their genomic organizations were similar and that their products had similar molecular masses and isoelectric points. Images
Whither or Wither Global Labour

Those of us who work in the garden of international labour repeatedly hope for a great flowering of global solidarity but usually find only slim harvests. We have become used to a broad gap between the rhetorical promise of global labour movements and the improvements in the lives of workers around the world that such global efforts actually bring. Thus observers of the workings of international labour organizations and of the connections of unions across borders search hard for the small shoots of collaboration that we imagine may someday allow unions to operate effectively in a globalized world. But all too often, we let our hopes overwhelm our analytical minds. The Seattle demonstrations of 1999 inspired this writer and many others with visions of a revitalized global left based on the coalition of a new generation of labour, environmentalist, and social justice activists. This renewed left quickly created ongoing connections through institutions like the World Social Forum as counterparts to those of the global elite and appeared to be having some progressive world effects. Rejecting simplistic protectionism as counterproductive and doomed, leftists spawned proposals for “globalization from below,” to use the title of a hopeful book of the time. Trade unions around the world not only participated in this wider left, but also launched reforms of their own to revitalize the global side of their movement. Cold War divisions fell as one-time Communist labour organizations joined the International Confederation of Free Trade Unions (icftu), an organization of national review essay / note critique
Endometrial cancer in a 14-year-old girl with Cowden syndrome: A case report

The appearance of endometrial cancer in adolescence is uncommon and warrants investigation for an hereditary cancer syndrome. Cowden syndrome is an autosomal dominant cancer syndrome associated with a germline PTEN mutation and increased risk of breast, thyroid, endometrial and colon cancer. In this report we present a case of a 14-year-old nulligravid female diagnosed with grade 1 endometrial adenocarcinoma. She subsequently developed fibrocystic breast disease and colon polyps and was diagnosed with Cowden syndrome at age 20. We therefore recommend formal evaluation for Cowden syndrome to be considered when endometrial cancer is diagnosed in adolescence.
Electric Field Effects on Natural Convection in Enclosures

Modes de couplage des equations de Navier-Stokes aux equations de Maxwell de l'electrodynamique. Effets de ces couplages sur le transfert de chaleur convectif
Phytoplankton Regulation in a Eutrophic Tidal River (San Joaquin River, California)

As in many U.S. estuaries, the tidal San Joaquin River exhibits elevated organic matter production that interferes with beneficial uses of the river, including fish spawning and migration. High phytoplankton biomass in the tidal river is consequently a focus of management strategies. An unusually long and comprehensive monitoring dataset enabled identification of the determinants of phytoplankton biomass. Phytoplankton carrying capacity may be set by nitrogen or phosphorus during extreme drought years but, in most years, growth rate is light-limited. The size of the annual phytoplankton bloom depends primarily on river discharge during late spring and early summer, which determines the cumulative light exposure in transit downstream. The biomass-discharge relationship has shifted over the years, for reasons as yet unknown. Water diversions from the tidal San Joaquin River also affect residence time during passage downstream and may have resulted in more than a doubling of peak concentration in some years. Dam construction and accompanying changes in storage-and-release patterns from upstream reservoirs have caused a long-term decrease in the frequency of large blooms since the early 1980s, but projected climate change favors a future increase. Only large decreases in nonpoint nutrient sources will limit phytoplankton biomass reliably. Growth rate and concentration could increase if nonpoint source management decreases mineral suspensoid load but does not decrease nutrient load sufficiently. Small changes in water storage and release patterns due to dam operation have a major influence on peak phytoplankton biomass, and offer a near-term approach for management of nuisance algal blooms.
Menu Auctions, Resource Allocation, and Economic Influence

In many examples of competitive bidding (e.g., government construction contracting) the relevant object is either partially divisible or ill-defined, in contrast to much of the recent theoretical work on auctions. In this paper we consider a more general class of auctions, in which bidders name a "menu" of offers for various possible actions (allocations) available to the auctioneer. We focus upon "first-price" menu auctions under the assumption of complete information, and show that, for an attractive refinement of the set of Nash Equilibria, an efficient action always results. Our model also has application to situations of economic influence, in which interested parties independently attempt to influence a decision-maker's action.
Reliability of a k out of n system of components sharing a common environment

This paper deals with the reliability function and the failure rate of the k out of n system of components, with and without incorporating the environmental effect. Special cases of the series system and the parallel system provide more compact expressions and interpretations. Some of the results in the literature follow as our special cases. Examples are given to illustrate the results.
DNA double-strand breaks, chromosomal rearrangements, and genomic instability

DNA double-strand breaks can lead to chromosomal rearrangements at the first mitosis after exposure to the DNA strand-breaking agent. The evidence suggests a number of different pathways for DNA double-strand break rejoining in mammalian cells, but it is unclear what factors determine the fate of the induced break and whether or not it will lead to chromosomal rearrangement. If a cell does survive and proliferate after DNA cleavage, delayed chromosomal instability can be observed in the clonal descendants of the exposed cell. Most, but not all DNA double-strand breaking agents are effective at inducing this delayed chromosomal instability. In this paper, we review the evidence for the role of the DNA double-strand break in directly induced and delayed chromosomal rearrangements.
Past, present, and future of perpendicular magnetic recording

The past, present, and future developments of perpendicular magnetic recording are discussed.
Fragile Pages of Grey Ashes Inoperative archives in Dubravka Ugrešić's The Museum of Unconditional Surrender and David Markson's Wittgenstein's Mistress

This essay begins with a consideration of the burning of the National and University Library in Sarajevo in 1992, drawing from a description of this event the problem of how to think of remainder and dispersal as the modalities of a common distribution. Posing the question of how to read an archive that is distributed through its vanishing, the article turns to two texts that have this question, but little else, in common. Evoking the contingent connections between two novels that would only uncommonly be read together, Dubravka Ugresic's The Museum of Unconditional Surrender and David Markson's Wittgenstein's Mistress, I ask how such texts might be drawn together at a site that is nothing other than the remainder of a dispersal. Attempting to engage that question formally, through its own practice of writing, the essay concludes by theorizing a comparative methodology that moves away from models of address, reconstruction, commemoration, or mourning and toward a circulation of texts and memory that is me...
The specific type IV phosphodiesterase inhibitor rolipram combined with adenosine reduces tumor necrosis factor-α-primed neutrophil oxidative activity

Monocytes and macrophages produce tumor necrosis factor-alpha (TNF alpha) in response to microbial products including endotoxin. TNF alpha is a potent primer of neutrophil (PMN) oxidative activity. Certain xanthine phosphodiesterase (PDE) inhibitors such as pentoxifylline have been shown to inhibit stimulated oxidative activity in PMN. In the present study, the non-xanthine PDE type IV inhibitor rolipram (4-[3'-cyclopentyloxy-4'-methoxyphenyl]-2-pyrrolidone) alone and in combination with adenosine is examined as a potential modulator of TNF alpha-primed PMN oxidative activity. Attainable in vivo concentrations of rolipram and physiological concentrations of adenosine alone and together synergistically decreased rhTNF alpha-primed suspended PMN oxidative activity stimulated by the chemoattractant f-met-leu-phe. The rolipram effect was reversible by washing, and rolipram had a comparable effect if added before or after priming, indicating that its effect was on the primed response rather than on priming per se. In addition, rolipram especially when combined with adenosine, decreased rhTNF alpha-stimulated PMN adherence to a fibrinogen-coated surface, and the oxidative burst of rhTNF alpha-stimulated adherent PMN. The specific adenosine A2a receptor agonists CGS 21680 and WRC-0474 had comparable activity to adenosine in these experiments. Adenosine (or CGS 21680) combined with rolipram synergistically increased f-met-leu-phe-stimulated PMN cAMP content. The effects of both adenosine and rolipram with adenosine could be only partly counteracted by treatment of the PMN with the protein kinase A inhibitor KT 5720, indicating that protein phosphorylation is only partially involved. Rolipram activity was about 1000 x (by molar concentration) greater than pentoxifylline in comparable assays. Thus, rolipram, especially when combined with adenosine, has potent modulating effects on PMN activation and may be useful in decreasing inflammatory tissue damage in patients with sepsis.
Polyamine Depletion Induces Rapid NF-κB Activation in IEC-6 Cells

The proliferation of the rat intestinal mucosal IEC-6 cell line requires polyamines, whose synthesis is catalyzed by the enzyme ornithine decarboxylase (ODC). ODC inhibition leads to polyamine depletion, as well as inhibition of both cell proliferation and apoptosis by regulating gene expression. The NF-κB transcription factor regulates genes involved in apoptotic, immune, and inflammatory responses. In the present study we tested the hypothesis that NF-κB is activated following ODC inhibition. We found that the inhibition of ODC by α-difluoromethylornithine (DFMO) resulted in a ∼50% decrease in intracellular putrescine levels within 1 h. NF-κB is activated by DFMO through the degradation of the inhibitory protein IκBα that sequesters NF-κB in the cytoplasm. The DFMO-induced NF-κB complexes contain the p65 and p50 members of the Rel protein family. DFMO-induced NF-κB activation was accompanied by the translocation of p65 from the cytoplasm into the nucleus. DFMO selectively inhibited a gene reporter construct dependent on the κB site present in the HLA-B7 gene. In contrast, DFMO had no effect on a gene reporter construct dependent on the κB site present in the interleukin-8 gene. Thus, we report that ODC inhibition activates the NF-κB transcription factor, which may mediate the altered physiological state of intestinal cells that occurs following polyamine depletion.
Crystallization and X-ray diffraction analysis of an all-RNA U39C mutant of the minimal hairpin ribozyme.

The hairpin ribozyme is a naturally occurring catalytic RNA composed of two helix-loop-helix domains, A and B, that dock to form the biologically active enzyme. Previously, the crystal structure of the hairpin has been solved as a four-way helical junction that incorporated the U1A protein as an artificial crystal-packing motif [Rupert & Ferre-D'Amare (2001), Nature (London), 410, 780-786]. Here, the crystallization of a minimal junctionless hairpin ribozyme 64-mer is reported in the absence of protein. Crystals grow in space group P6(1)22, with unit-cell parameters a = 93.1, c = 123.2 A. Complete diffraction data have been collected to 3.35 A resolution. Structural analysis should provide details of intermolecular RNA docking, including the ground-state conformations of the U(39)C mutation relevant to hairpin catalysis.
Purchasing cd-rom products: Considerations for a new technology

Abstract This article outlines primary considerations in the acquisition of CD-ROM products. The advantages and disadvantages of CD-ROM technology are delineated, and approximately 30 products are listed. A statement about collection development goals is included, as is a summary of equipment needs and a selected bibliography.
Relationship of patient-nurse activity to intracranial pressure variations: a pilot study.

Persons with increased intracranial pressure (ICP) from all causes are subject to periods of markedly increased pressure. Research since the initial clinical studies in the early 1960s has focused primarily on characteristics of ICP variations in specific pathologies and on mechanisms basic to increases in ICP rather than on the relationship between basic patient-care activities, such as moving the patient in bed, and variations in ICP. Therefore, nine patients with pressure-controlled ventriculostomy drainage systems were observed continuously for up to 24 hours to determine whate, if any, patient-nurse activities were associated with transient of sustained increased ICP. Frequencies of ventricular fluid drainage (VFD) during activity and nonactivity were compared to predicted frequencies. One patient had no VFD; eight patients had greater than predicted incidence of VFD associated with activity and less than predicted incidence associated with nonactivity. The difference between predicted and actual incidence of VFD was statistically significant (p less than .001) for all eight patients. Although each patient displayed individual patterns of specific activity associated with VFD, turning in bed and conversation about the patient's condition were consistent among the sample. Coughing, chewing use of bedpan, and restless movemenss were consistently associated with VFD in patients.
Investigation of the strength contrast at the Moho: A case study from the Oman Ophiolite

We investigate the viscosity contrast between the crust and mantle by analysis of deformed gabbronorite dikes in the mantle section of the Oman Ophiolite. Our study provides a rare opportunity to directly constrain the rheological contrast between a plagioclase-rich lithology typical of the lower crust and an olivine-dominated harzburgite. We constrain deformation conditions using field relationships, geothermometry, grain size piezometry, and electron backscatter diffraction. The viscosity of gabbronorite was at least two orders of magnitude lower than the viscosity of the harzburgite, consistent with the rheological contrast between plagioclase and olivine calculated via experimental flow laws. These flow laws predict that a significant viscosity contrast exists at the crust-mantle boundary where the crustal lithology is dominated by plagioclase, or where deformation localizes within plagioclase-rich layers.
Modern Microphone Array for Hearing Aid and Speech Processing

For various audio, teleconference, hearing aid, and voice recognition applications, a microphone array is known to be an effective method to enhance the SNR in noisy environments resulting in significant improvement of speech intelligibility or recognition. We propose an novel electronically steerable microphone array based on the Maximum Energy concentration criterion to form a focused beam toward the desired speech source, attenuating background noises and rejecting discrete spatial interferers. The design and implementation of a prototype DSP-based microphone array system are described. Some details on microphone measurement, calibration, and optimization needed to achieve a high performance microphone array are discussed. Computer simulated and measured array performances are presented to show the effectiveness of the array system.
The effect of helium-oxygen mixtures on pulmonary function in asthmatic patients.

Abstract Eight patients with bronchial asthma were given air and a helium-oxygen mixture to breathe, and spirograms and measurements of speed of flow were obtained. In the severely ill patients, no significant change was observed in the expiratory reserve volume, the inspiratory capacity, the vital capacity, or the speed of flow during the performance of the vital capacity. In some measurements among the less ill patients, slightly larger values were obtained with helium.
Spidroin N-terminal Domain Promotes a pH-dependent Association of Silk Proteins during Self-assembly

Spider silks are spun from concentrated solutions of spidroin proteins. The appropriate timing of spidroin assembly into organized fibers must be highly regulated to avoid premature fiber formation. Chemical and physical signals presented to the silk proteins as they pass from the ampulle and through the tapered duct include changes in ionic environment and pH as well as the introduction of shear forces. Here, we show that the N-terminal domain of spidroins from the major ampullate gland (MaSp-NTDs) for both Nephila and Latrodectus spiders associate noncovalently as homodimers. The MaSp-NTDs are highly pH-responsive and undergo a structural transition in the physiological pH range of the spider duct. Tryptophan fluorescence of the MaSp-NTDs reveals a change in conformation when pH is decreased, and the pH at which the transition occurs is determined by the amount and type of salt present. Size exclusion chromatography and pulldown assays both indicate that the lower pH conformation is associated with a significantly increased MaSp-NTD homodimer stability. By transducing the duct pH signal into specific protein-protein interactions, this conserved spidroin domain likely contributes significantly to the silk-spinning process. Based on these results, we propose a model of spider silk assembly dynamics as mediated through the MaSp-NTD.
Has Total Hip Arthroplasty in Patients 30 Years or Younger Improved? A Systematic Review

Background The evolution of total hip arthroplasty (THA) generally has led to improved clinical results. However, THA in very young patients historically has been associated with lower survivorship, and it is unclear whether this, or results pertaining to pain and function, has improved with contemporary THA.
Early language intervention: A deterrent to reading disability.

Reading is a language art! In acquiring competence in reading we build on proficiencies already available in the primary (spoken) language system. Language is made up of three primary components that impact on reading—phonology, or the sound structure of language including syllables and phonemes; syntax, or the rules governing the sequential ordering of words in phrases and sentences; and semantics, or the meaning system that is attached to words and phrases as a consequence of experiences in a variety of contexts. All three depend upon adequate short- and long-term memory capacities and functioning for their growth and refinement. Additionally, the bridging of speech to print, or the task of establishing sound/symbol correspondences in beginning reading draws not only upon phonological competencies and memory, it is also dependent upon the discovery that words are made up of smaller and isolable parts. This knowledge is often referred to as auditory segmenting which is one aspect of metalinguistic awareness.
Phthalocyanine dimerization-based molecular beacons using near-IR fluorescence.

Herein we demonstrate the use of a novel dimerization-based molecular beacon (MB) probe consisting of two metallo-phthalocyanine (Pc) fluorophores that use near-IR fluorescence, appropriate for highly specific and sensitive in vivo and/or in vitro DNA/RNA detection. Pcʼs possess a propensity to form nonfluorescent H-dimers that is utilized as the molecular “off” switch in the closed MB conformation. The “on” switch, which is generated when the solution target binds to the loop of the MB forming the open form, also provides two fluorophores for transduction resulting in a doubling of the extinction coefficient and improving the resulting fluorescence yield compared to a classical single-fluorophore/quencher MB system. In addition, the Pc-based MBs possess high thermal, photo, and chemical stabilities that are essential for many highly sensitive applications, such as molecular imaging. The dimer-based MBs were obtained using a simple single-step synthesis procedure and demonstrated excellent quenching effic...
Quantified small-scale turbulence inhibits the growth of a green alga

1. Laboratory experiments were conducted to elucidate the effect of small-scale turbulent fluid motion on the growth of laboratory cultures of the freshwater algae Scenedesmus quadricauda. Turbulent flow was generated using an oscillating-grid apparatus. The experiments were performed under the range of fluid flow conditions similar to those occurring in nature. The only growth limiting factor was the effect of small-scale fluid motion; all other environmental factors, such as light, temperature and nutrients, were kept constant. 2. Growth of Scenedesmus quadricauda, measured in terms of chlorophyll a concentration, was inhibited when the level of turbulence in the water column was increased. Algal growth was maximum in a quiescent fluid. The inhibitory effect of fluid motion was observed independently of flow regime (laminar, transitional, turbulent) in the water column. 3. Cell destruction and aggregation of dead and living cells of algae were observed in a turbulent flow. High shear rates, estimated from the dissipation of turbulent kinetic energy, caused the cell destruction, algal collision and agglomeration of algae. Data on Scenedesmus responses to small-scale fluid motion will enhance and broaden our ability to develop predictive multispecies models for freshwater phytoplankton communities.
The place of science in the health professions.

SUMMARY The central premise of this paper is that medical education today is being driven by intellectual and social imperatives to make fundamental changes in the way it prepares students to be the doctors of tomorrow. Fully aware that over the past 50 years at least eight major national commissions in the USA alone have made similar claims, the present reality is such that the pressure for change has greater force than at any time since the beginning of the century, when the overall form of modern medical education was set. The new science base of medicine requires the activation of its students. Although medical educators have recognized for at least half a century that active student learning is preferable to the passive student roles of didactic methods, we no longer have a choice. Not only is the activated student a requisite for learning that is intrinsic to the new intellectual paradigm, it is necessary for its application in clinical practice. At the same time, it is important to recognize that the social organization of medical education is structured to resist the kinds of changes that are inherent to the basic knowledge and practice requirements of contemporary medicine. The modern medical centre contains vested bureaucratic and financial interests, shared by both scientists and practitioners, which form a highly resistent structural barrier to change.
Stereospecific allylation of ribo and galacto aldosulose derivatives

Abstract By varying the nature of the Lewis Acid catalyst in the Sakurai reaction, highly selective allylation of the side chain aldehydes can be achieved.
Schwann cell transplantation improves reticulospinal axon growth and forelimb strength after severe cervical spinal cord contusion

Schwann cell (SC) implantation alone has been shown to promote the growth of propriospinal and sensory axons, but not long-tract descending axons, after thoracic spinal cord injury (SCI). In the current study, we examined if an axotomy close to the cell body of origin (so as to enhance the intrinsic growth response) could permit supraspinal axons to grow onto SC grafts. Adult female Fischer rats received a severe (C5) cervical contusion (1.1 mm displacement, 3 KDyn). At 1 week postinjury, 2 million SCs ex vivo transduced with lentiviral vector encoding enhanced green fluorescent protein (EGFP) were implanted within media into the injury epicenter; injury-only animals served as controls. Animals were tested weekly using the BBB score for 7 weeks postimplantation and received at end point tests for upper body strength: self-supported forelimb hanging, forearm grip force, and the incline plane. Following behavioral assessment, animals were anterogradely traced bilaterally from the reticular formation using BDA-Texas Red. Stereological quantification revealed a twofold increase in the numbers of preserved NeuN+ neurons rostral and caudal to the injury/graft site in SC implanted animals, corroborating previous reports of their neuroprotective efficacy. Examination of labeled reticulospinal axon growth revealed that while rarely an axon was present within the lesion site of injury-only controls, numerous reticulospinal axons had penetrated the SC implant/lesion milieu. This has not been observed following implantation of SCs alone into the injured thoracic spinal cord. Significant behavioral improvements over injury-only controls in upper limb strength, including an enhanced grip strength (a 296% increase) and an increased self-supported forelimb hanging, accompanied SC-mediated neuroprotection and reticulospinal axon growth. The current study further supports the neuroprotective efficacy of SC implants after SCI and demonstrates that SCs alone are capable of supporting modest supraspinal axon growth when the site of axon injury is closer to the cell body of the axotomized neuron.
Isolation and characterization of lipocortin (lipomodulin)

Lipocortin is a phospholipase inhibitory protein whose synthesis is induced in various cells by glucocorticoids. At least three species with molecular weights of 40,000, 30,000, and 15,000 are presently known. This protein mimics the anti-inflammatory action of glucocorticoids in vitro as well as in vivo. The synthesis of the protein appears to be associated with the MHC genes.
Elderly subjects are impaired in spatial coordination in fine motor control

Elderly and young control subjects performed back-and-forth handwriting movements in various orientations, therefore varying the coordination demands. Elderly subjects showed higher normalized jerk and straightness scores than the young subjects. However, jerk scores were independent of the coordination demands in either group. In contrast, the straightness scores were highly dependent on stroke orientation for the elderly, but they remained constant across orientations for the young controls. Moreover, group differences in stroke size and stroke duration were not significant, and orientation effects were unrelated. It is suggested that the orientation-dependent straightness scores in the elderly may result from unequal timing or improper scaling of muscle forces. These data suggest that aging deteriorates the spatial coordination of finger and wrist movements, but not accelerative force control.
Preventing Future Oil Spills with Software-Based Event Detection

Complex event processing systems detect problems in mission-critical, real-time applications and generate intelligent decisions to modulate the system environment.
In-operando optical imaging of temporal and spatial distribution of polysulfides in lithium-sulfur batteries

Abstract Understanding the behavior of soluble intermediate lithium polysulfide species is vitally important for improving the electrochemical performances of lithium-sulfur batteries. Herein we explore a simple in-operando lithium-sulfur cell design to enable direct visualization of the formation of the soluble polysulfide species and their temporal and spatial distribution over the entire discharge/charge cycle under an optical microscope. Our results reveal detailed evidence of electrochemical degradation in lithium-sulfur batteries and help us to understand the improvements in electrochemical performances using advanced lithium-sulfur cell designs. As examples, we show that a cathode consisting of hollow sulfur nanoparticles with a conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) coating exhibits significantly reduced dissolution of polysulfides into the electrolyte, and thus superior electrochemical performance could be achieved. Moreover, the trapping of soluble polysulfide species in the cathode side was also confirmed in our designed in-operando lithium-sulfur cell with a Nafion modified separator.
Brachial artery retrograde flow increases with age: relationship to physical function

The purpose of this study was to examine the flow velocity pattern of the brachial artery and to determine its relationship to measures of physical function. Subjects from the Louisiana Healthy Aging Study (n = 95; age = 84 ± 10 years) were evaluated. Brachial artery flow velocities and dimensions were measured using high-resolution ultrasonography. The continuous scale of physical function and performance test (CS-PFP10) was used to assess physical function. This test is based on the performance of 11 activities of daily living. Total CS-PFP10 score was 39.51 ± 21.21 U. Mean antegrade and retrograde velocities at rest were 14.2 ± 4.7 and 3.6 ± 2.2 cm/s, respectively. Ante-/retrograde ratio was 5.5 ± 4.6. Brachial artery diameter was 4.3 ± 0.7 mm. Pulse pressure and vascular conductance were 66 ± 18 mmHg, and 0.9 ± 0.5 ml/min/mmHg, respectively. Vascular conductance (r = −0.34), ante-/retrograde ratio (r = −0.42) and CS-PFP10 (r = −0.65) were inversely and retrograde velocity (r = 0.40) and pulse pressure (r = 0.36), were directly associated with age. Retrograde velocity was inversely related to vascular conductance (r = −0.27) and CS-PFP10 total score (r = −0.45). A MANOVA revealed that those with the higher CS-PFP10 scores had a lower retrograde velocity (P = 0.0001), but this association was, in part, age-dependent. Among nonagenarians (n = 52), those in the lower tertiles of the CS-PFP10 scores had significantly higher retrograde velocities compared to those in the higher tertiles (P = 0.035). These data indicate an increase in brachial retrograde velocity with age. These hemodynamic changes are related to a decline in physical function.