cssi/SciSciGPT-SciSciNet huggingface dataset:
Performance of St707 getter material in a rep-rated high power microwave sealed-tube vircator under UHV conditions

This study focuses on the use of St707 non-evaporable getter (NEG) material in a high power microwave (HPM) sealed-tube virtual cathode oscillator (vircator) operated at 500 Hz repetition rate. High-current pulsed operation releases gases trapped within the bulk materials and gas monolayers on material surfaces, leading to localized plasma production in the A-K gap. This can lead to gap closure, shorten the duration of microwave emission, and spoil vacuum. A single current pulse increases the chamber pressure to the low 10−6 Torr range from an initial background pressure in the low 10−9 Torr range, desorbing approximately 1014 particles. At 500 Hz operation, a sufficiently large pumping speed (∼2,500 L/s) is necessary to evacuate desorbed particles from the vircator volume during consecutive shots. Previous work has identified hydrogen (H, H 2 ) as the main outgassing species during vircator operation, with contributions from CH 4 , N 2 , CO, CO 2 , and Ar as the other primary gas constituents[1]. The St707 NEG pumps shows an affinity for pumping hydrogen, making it a suitable choice to adsorb vircator outgassing species, of which hydrogen is an order of magnitude greater than any other gas species. Previously, without the presence of NEG material, degradation of microwave output power from the vircator has been observed during subsequent shots at 1 Hz, 10 second burst mode operation. Subsequently, an increase in chamber pressure from 1.25×10−6 Torr on the first shot to 10−5 Torr on the tenth shot has been experimentally observed. This paper details the performance of the St707 NEG material (70% Zr, 24.6% V, 5.4% Fe) for maintaining UHV conditions during rep-rated vircator operation. Pumping characteristics of multiple St707 NEG pumps in the presence of rep-rated high-current pulses are presented. Diagnostic results obtained with a residual gas analyzer to observe individual gas constituents and two inverted magnetron cold cathode gauges for absolute pressure are utilized to analyze vircator and getter performance in detail.
Single-cell chemical lysis in picoliter-scale closed volumes using a microfabricated device.

Investigating the intracellular contents of single cells is essential for understanding physiologic and pathologic processes at the cellular level. While existing protocols for cell lysis and sample preparation work well for larger samples, scaling to a single-cell level is challenging because of unavoidable analyte dilution and losses. Thus, we are proposing a microfabricated device for the controlled handling and mixing of picoliter cell suspension and lysis solution volumes. Cells and fluids are independently isolated in two microchambers of 25-pL volumes using the geometry of the microchannels and the coordinated action of four on-chip thermopneumatic actuators. Virtual walls formed by liquid−air interfaces in the hydrophobic capillary separate the two volumes, which are subsequently allowed to mix after drawing the air out of the capillary connecting the two microchambers. Following cell lysis, a limited and stable dilution of intracellular components is achieved, simplifying the requirements for sub...
Design of Simulation Tools for Trainig Programs in Lean Manufacturing

Lean Manufacturing is a powerful philosophy, which advocates minimization of waste throughout the value stream both within the organization and enterprise which includes the supply chain. A concept, which was first used by automobile manufacturers to enhance their operational efficiencies, Lean focuses on driving out non-value added activities from a company’s operation, while streamlining its value added activities. A number of companies in the United States have adopted the Lean Manufacturing philosophy to reduce cost and increase efficiency. To augment the existing training programs five new simulation tools in Ship Design Processes, Supply Chain Integration, Ship Repair Processes, Value Stream Mapping and Scheduling were developed under a grant from National Shipbuilding Research Program (NSRP) by Old Dominion University, Northrop Grumman Newport News and South Tidewater Association of Ship Repairers. The paper will discuss the design, development and implementation of two of these new simulation tools.Copyright © 2005 by ASME
A variant of frobeniu' method for the emden fowler equation

In this note, special solutions of the Emden Fowler equations are constructed by Puiseux expansions. The approach is a generalisation of the Frobenius theory at regular singular points of linear analytic differential equations. Convergence of the expansions is proved by a contraction argument. It is shown that two different families of solutions are constructible via Puiseux expansions. The solutions reduce to Bessel functions for exponent β = 1, where the equation gets linear, and to the homoclinic loop at the second critical exponent β2. The relation to the seperatrices from the phase plane systems introduced by Rothe in [17], as well as van den Broek and Verhulst in [5] is established. One of the two families of solutions are just the well known (E) solutions arising in the description of selfgravitating polytropic gasspheres. The mass radius relation of polytropic gasspheres as discussed in Shapiro and Teukolsky [18] is extended to exponents from zero up to the second critical exponent.
Aging of polyurethane foams

Abstract The degradation of foam thermal properties due to the diffusion of the air into the foam, termed the foam aging, is a major drawback of polyurethane foams. An analytical model was developed to predict the effective diffusion coefficient of the foam and from it the rate of gas diffusion and foam aging. The model requires a measurement of the wall permeability and foam internal geometry. An experimental steady-state technique was developed to measure the permeability of the cell walls. To check the models an experimental technique was developed to measure the foam effective diffusion coefficient. The model predictions of the effective diffusion coefficient were found to be within 29% of the foam data or better.
Solar cycle length and 20th Century northern hemisphere warming: Revisited

It has been suggested that the length of the solar cycle (SCL) is related to solar forcing of global climate change [Friis-Christensen and Lassen, 1991]. Although no physical mechanism had been proposed, the relation seemed to be supported by interesting correlations with several paleoclimate records and, separately, with the 20th century Northern Hemisphere instrumental record. Actually, what has been correlated is the quasi-sinusoidal Gleissberg cycle which is slightly greater in the 18th century than in the 20th century. Using the pre-industrial record as a boundary condition, the SCL-temperature correlation corresponds to an estimated 25% of global warming to 1980 and 15% to 1997.
Size effects and the shear response of aluminum foam

Abstract Aluminum foam samples produced by the melt route were subjected to static and quasi-static low-rate shear deformation using a specially designed loading fixture. Characteristic response curves are presented for a range of relative densities (3.1–15%). For the range of densities examined, the shear modulus shows a linear dependence on relative density, while the ultimate strength follows a non-linear power law. Over the range of strain rates examined, the aluminum foam shear response is shown to have no rate dependence in the linear regime, while the ultimate strength and energy absorption are strain rate dependent, increasing by 24% and 63%, respectively. Size effects in shear deformation are examined with optical techniques through which the average shear strain is calculated over sub-regions of the sample. The strain in these sub-regions deviates significantly from the global applied strain for regions smaller than 18 mean cell diameters, indicating a critical specimen size, below which certain bulk properties are no longer representative.
Method of Multiple Reference Frames Applied to the Analysis of Symmetrical Induction Machinery

A method of analyzing the constant-speed performance of a symmetrical induction machine with applied stator phase voltages of any periodic form is presented. Symmetrical components are not used in this analysis. Instead, it is shown that by employing a series of reference frames, dc circuit theory may be used to determine the performance of induction machines. Since phasor and complex impedance concepts are not incorporated, the theory of multiple reference frames permits a convenient and simple method of analyzing steady-state modes of unbalanced or nonsinusoidal operation which have heretofore been limited to analysis by the method of symmetrical components. Also, this method establishes a rigorous approach to the analysis of constant-speed electrical transients of induction machinery.
A time-dependent parameter acquisition system for the characterization of MOS transistors and SONOS memory devices

An inexpensive and fully automated test station is described for the dynamic characterization of MOS and SONOS devices. The system incorporates a novel circuit which monitors the extrapolated threshold, transconductance, and subthreshold slope over time; onboard circuitry to place the system into one of several different modes of operation; an IEEE-488 interface to a controlling desktop computer; and a control program which performs several different measurement functions. Nonvolatile memory transistors are evaluated by the use of memory retention, programming, and endurance measurements, while short-channel MOS transistor reliability under DC and AC voltage stress is evaluated by monitoring the degradation in threshold and transconductance over time. >
Geocomputation's future at the extremes: high performance computing and nanoclients

Recent developments in computing are reviewed, with consideration given to the nature of the human-computer interface and its development. The emergence of the desktop metaphor and the Windows-Icons-Menus Pointers interface, while suitable for most computing tasks, has now played out its course as far as innovation in hardware is concerned. The next phase of computing is only now emerging, and is being fed by changes at the "extremes" of computing, the parallel supercomputer at one end, and the extremely thin or "nano" client at the other. The paradox, of fat servers and ultrathin clients implies a further separation toward the extremes as systems develop. Examples are given of nanoclients, including wearable computers, smart dust, microelectromechanical systems and wireless integrated network sensors. Clearly, the user interface for nanoclients must explicitly or implicitly include geographical space, because the primitive of location, coordinates, will often be a critical part of the data stream. At the parallel and HPC end, the advantages and types of parallel computing are discussed, and examined in the light of what they can do for geographical systems. Some examples of the computing extremes are given in terms of application, including wearable computers, and geo-smart dust. Finally, the relationship between massive combined computing power at both the client and server side are considered in the light of tractability in geoscience. It seems quite likely that a new suite of methods, based in computing, will emerge to replace the standard set of mathematical tools, such as optimization methods, in use today.
A very high density floating electrode flexible sensor array for high-resolution measurements of contact forces

We present the development, fabrication and testing results of a new high-density flexible sensor array (HDFA) suitable of recording three-axis stresses with high spatial resolution. The new HDFA consists of 676 (26×26) sensing cells fabricated on top of a high-density flex circuit substrate. Each sensing cell is implemented using four floating comb electrodes separated from the flex substrate by a thin layer of a compressible PDMS film. Each sensing cell measures 2.77×2.55 mm2 thus packing 2704 capacitors in an area of ~ 50 cm2. The HDFA is read using a high-speed switched-capacitor circuit with a 13-bit resolution at full frame rates of 100 Hz (~0.8Mb/s). The new array is capable of detecting contact line displacements as low as 35 μm and contact line velocities as low as 38 μm/s.
Unpolarized nucleon structure studies utilizing polarized electromagnetic probes

By the mid-1980s, measurements of the nucleon form factors had reached a stage where only slow, incremental progress was possible using unpolarized electron scattering. The development of high quality polarized beams, polarized targets, and recoil polarimeters led to a renaissance in the experimental program. I provide an overview of the changes in the field in the last ten years, which were driven by the dramatically improved data made possible by a new family of tools to measure polarization observables.
Activation of prothrombin with Taipan snake venom

Abstract Thrombin formation in mixtures of purified prothrombin, Taipan snake venom, phospholipid, and CaCl2 was studied as a function of varying concentrations of individual components of the reaction mixture. Under optimal conditions prothrombin yielded stable thrombin activity, rapidly and quantitatively, providing the basis for a convenient assay of purified prothrombin.
In situ evidence for chirality-dependent growth rates of individual carbon nanotubes.

The large-scale synthesis of single-walled carbon nanotubes (SWCNTs) with controlled chirality—which could find applications in fields such as electronics—remains a great challenge. It is now shown that the growth rates of SWCNTs are directly proportional to their chiral angles, suggesting a route towards selective synthesis based on kinetic control.
Measuring changes in social behavior during a social skills intervention for higher-functioning children and adolescents with autism spectrum disorder.

The social behavior of children and adolescents with Autism Spectrum Disorder was evaluated weekly over 19 weeks of a social skills training program. Participants’ vocalizations were coded as initiating, responding, or other (e.g., self-talk). Participants’ interactions were coded as dyadic peer interactions, dyadic leader interactions, interactions with a group of peers, interactions with a group of peer(s) and leader(s), or time spent by self. Over the course of the intervention, participants made fewer initiating and other vocalizations, more responding vocalizations, spent more time interacting with a group of peers, and spent marginally less time interacting with a leader. Gender, age, and intervention attendance effects on social behavior are also noted.
Facile Fabrication of Nanosized Nickel Powder via Solid-State Reaction at Low Heat and its Catalytic Performance

Nano-Nickel (Ni0) powders have been successfully prepared via the reduction of nanosized NiO powders by the solid state reaction. And the nanosized NiO powders were derived from low temperature (350°C) calcinations in muffle in air of nanosized Ni(OH)2 powders firstly prepared by the room temperature solid state reaction between NiSO4•6H2O and NaOH by H2 at 400°C for 4 h. The crystallinity, microstructure of surface and xps property of obtained nickel powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Furthermore, the catalytic activity of the obtained nanosized Ni powders for hydrogenation of nitrobenzene to aniline was investigated. The results show that the spherical Ni parepared in particle sizes ranges from 20 to 25 nm and achieves enhanced catalytic activity for hydrogenation of nitrobenzene to aniline compared with Raney Ni.
THE TREATMENT OF SLEEP DISORDERS WITH MELATONIN

Fifteen children (most of whom were neurologically multiply disabled) with severe, chronic sleep disorders were treated with 2 to 10mg of oral melatonin, given at bedtime. Nine had fragmented sleep patterns, three had delayed sleep onset and three others had non-specific sleep disturbance of unclear aetiology; all had failed to respond to conventional management. Nine patients had ocular or cortical visual impairment. The health, behavioural and social benefits of treatment were significant, and there were no adverse side-effects. While the response was not always complete, the study clearly showed that melatonin has an important role in the treatment of certain types of chronic sleep disorders.
Water requirements of African goats and haired-sheep.

A number of species of desert-dwelling ungulates (e.g. Grant's gazelle and oryx) can apparently survive desert conditions without drinking. We were interested in finding out whether goats and sheep herded in the arid Northern Frontier Region of Kenya utilized the same physiological strategies for reducing water requirements as the wild ungulates.Using simulated desert conditions (12 h per day at22 °C alternating with 12 hper day at 40 °C) we found: (a) both goats and sheep used water amounting to about 8% of their body weight per day when water was available ad libitum; and (b) this was reduced to about half (or 4% body weight per day) when the water intake was restricted.Evaporation was the major avenue of water loss under all experimental conditions. It was reduced from over 6% of body weight per day to about 3% in the simulated desert by restricting water intake.Restricting water intake had no effect on the temperature regulation of goats and sheep as had been observed in the wild desert-dwelling ungulates.It would appear that African goats and haired-sheep lack the physiological mechanisms and are not free to utilize the behavioural mechanisms involved in freeing wild desert-dwelling ungulates from their dependence on drinking water.
Uniqueness and localization—I. Associative and non-associative elastoplasticity

Abstract Localization of deformation into a planar band in the incremental response of elasto-plastic material is studied in the case of small strains and rotations. The critical hardening modulus for localization is given in an explicit form (uncoupled from the band normal) for an arbitrary rate independent non-associative plasticity. Loss of uniqueness of the response is investigated in terms of positiveness of the second order work density. Criteria for loss of second order work positiveness and localization are compared for plane stress and plane strain. In these cases, for the associative flow rule, the threshold for the second order work positiveness coincides with the threshold for shear band formation. This coincidence may not, however, occur if localization into splitting mode is attained.
A84: Changes over Time in Symptoms and Treatment of Juvenile Primary Fibromyalgia Syndrome

Background/Purpose: There are limited data describing longitudinal trends of symptoms and outcomes among children seeking treatment for Juvenile Primary Fibromyalgia Syndrome (JPFS). Pediatric rheumatologists often are the first point of subspecialty contact for children and adolescents with JPFS and typically evaluate the outcome of their initial treatment recommendations over one or more follow-up visits. Using baseline and follow-up data entered into the Childhood Arthritis and Rheumatology Research Alliance (CARRA) registry for patients with JPFS, we sought to determine the extent to which symptoms, function, and treatment recommendations change over time in this patient population. Methods: Deidentified information on symptoms, treatments, and function (CHAQ scores, subjective well-being numerical rating scale, and 5-point HRQOL rating scale) were extracted from the CARRA registry for all baseline and follow-up entries between May 2010 and September 2013. Data were analyzed for 66 patients (38% of the baseline cohort) having at least one follow-up visit recorded in the registry; the follow-up period ranged from 0.25 to 2.5 years from baseline (M = .88 years +/− .51 years). The analyzed cohort was 82% female and ranged in age (at baseline) from 9–21 years (M = 15.0 +/− 2.28 years). Multilevel growth models were used to determine time-related trends in symptoms, function, and treatments since completion of baseline evaluation; logistic growth models were used for models with binary outcome variables. Results: Pain scores were in the moderate to severe range at baseline (M = 6.00/10, SD = 2.74) and significantly worsened over time (b = .43 ± .19, t(91) = 2.17, p = .03). Similarly, indicators of function and well-being either worsened over time (for CHAQ: b = .10 ± .05, t(111) = 2.05, p = .04; for subjective well-being: b = .67 ± .21, t(91) = 3.28, p <.01) or did not improve (for HRQOL: b = .03 ± .08, t(91) = .36, p = .72). These findings did not change when controlling for whether or not patients followed treatment recommendations. The likelihood of typical disease symptoms being reported as present (i.e., headache, sleep disruption, irritable bowel symptoms, subjective soft tissue swelling, and paresthesias) remained relatively constant over time, except for a reduced likelihood of reporting widespread pain over years since baseline (b = −.57 ± .22, t(91) = −2.53, p = .01). Treatment recommendations made by rheumatologists at baseline (e.g., physical therapy, counseling, biofeedback, medications) did not significantly change over time. Conclusion: Children with JPFS exhibit worsening pain and quality of life over time regardless of treatment modality recommendations or patient compliance to therapy. Patients returning for follow-up visits may be those whose symptoms are most refractory. Additional studies are needed to identify barriers to improvement in this patient population and to determine effective treatment approaches to improve health outcomes.
Complete amino acid sequence of human cartilage link protein (CRTL1) deduced from cDNA clones and chromosomal assignment of the gene.

Abstract Little is known about the primary amino acid structure of human cartilage link protein (CRTL1). We screened a human genomic library with a cDNA encoding the 3′ untranslated region and the adjoining B1 domain of chicken link protein. One clone was isolated and characterized. A 3.5-kb EcoRI-KpnI fragment from this genomic clone that contains the human B1 exon was used to map the gene to chromosome 5q13 → q14.1. The same fragment was used to screen a cDNA library prepared from mRNA of Caco-2, a human colon tumor cell line. Two overlapping clones were isolated and shown to encode all of CRTL1. The deduced amino acid sequence is 354 residues long. The amino acid sequence shows a striking degree of identity to the porcine (96%), rat (96%), and chicken (85%) link protein sequences. Furthermore, there is greater than 86% homology between the 3′ untranslated region of the genes encoding human and porcine link proteins. These results indicate that there has been strong evolutionary pressure against changes in the coding and 3′ untranslated regions of the gene encoding cartilage link protein.
Plague in San Francisco: an essay review.

[Rieux] knew what those jubilant crowds did not know but could have learned from books: that the plague bacillus never dies or disappears for good; that it can lie dormant for years and years in furniture and linen-chests; that it bides its time in bedrooms, cellars, trunks, and bookshelves; and that perhaps the day would come when, for the bane and the enlightening of men, it would rouse up its rats again and send them forth to die in a happy city.
Interpreting Abstract Interpretations in Membership Equational Logic

We present a logical framework in which abstract interpretations can be naturally specified and then verified. Our approach is based on membership equational logic which extends equational logics by membership axioms, asserting that a term has a certain sort. We represent an abstract interpretation as a membership equational logic specification, usually as an overloaded order-sorted signature with membership axioms. It turns out that, for any term, its least sort over this specification corresponds to its most concrete abstract value. Maude implements membership equational logic and provides mechanisms to calculate the least sort of a term efficiently. We first show how Maude can be used to get prototyping of abstract interpretations ``for free.'''' Building on the meta-logic facilities of Maude, we further develop a tool that automatically checks an abstract interpretation against a set of user-defined properties. This can be used to select an appropriate abstract interpretation, to characterize the specific loss of information during abstraction, and to compare different abstractions with each other.}
A review of ECT for children and adolescents.

ABSTRACT Two cases of electroconvulsive therapy (ECT) in adolescence are presented and the literature on the use of ECT in childhood and adolescence is reviewed. ECT was effective in children and adolescents with bipolar disorder and depression. Inadequate information exists to make a judgment regarding schizophrenia, delirium, and anorexia nervosa. ECT is not effective in autism and chronic organic brain syndromes. Complications cited include organicity and seizures in the period immediately after ECT, anxiety reactions, and disinhibition. Long-term memory deficit or cognitive impairment has not been found, although further research to rule out residual impairment is needed.
Is the glass half empty or half full? Good news for caregivers

Caregivers of Alzheimer's patients are faced with a tremendously trying task. It is imperative that caregivers are knowledgeable about strategies and techniques for caring for patients. This article explains creative and effective methods of dealing with AD patients. Some of these care techniques are adapted from other disciplines. It is suggested that these care techniques are shared through support groups, or by telephone or written correspondence.
The World Bank and Poverty: A Review of the Evidence on Whether the Agency Has Diminished Emphasis on Aid to the Poor

. The World Bank's loan patterns in recent years are examined to see if there is any empirical evidence of a diminution of interest in poverty alleviation programs. Four very different concepts on what poverty alleviation is are used to categorize the international agency's loans: the share of lending going to (1) poor countries; (2) programs targeting direct aid to poor individuals; (3) certain sectors deemed to be intrinsically beneficial in meeting basic human needs, and (4) overall country programs which make poverty a key element of their goals. Each of the concepts has different criteria and standards. Analysis of the data indicates that the Bank seems to be doing at least as well today in the struggle against poverty as in previous decades. In some ways the Bank's current program is more poverty-oriented than are bilateral aid programs financed by the United States and other major donor countries.
Computer detection of premature ventricular complexes: A modified approach

Abstract The accuracy of a data reduction system for arrhythmia detection in identifying premature ventricular complexes was evaluated in continuous tape records of 30 patients in a coronary care unit. Computer analysis was performed with a Honeywell 316 digital computer. Threshold values for dominant complexes were automatically determined and recognition of premature ventricular complexes was based on differences in QRS configuration, timing and T wave configuration from the dominant complexes. Verification of the computer accuracy in detecting premature ventricular complexes was made with visual beat by beat inspection using a two channel strip chart recorder with simultaneous recording of the electrocardiogram and computer signal. This procedure allowed for exact beat to beat correlation and, thus, absolute determination of false positive and false negative identifications. From 0.5 to 6 continuous hours of monitoring per patient (average 3.5 hours) were analyzed for a total of 105 monitoring hours. The basic cardiac rhythms noted were normal sinus rhythm, sinus arrhythmia, sinus tachycardia, demand pacemaker rhythm, atrial fibrillation and atrioventricular (A-V) dissociation with junctional rhythm. Premature ventricular complexes were evident in 28 tapes (93 percent) including 12 (43 percent) with multifocal premature ventricular complexes and 3 (11 percent) with ventricular tachycardia. The visual count of premature ventricular complexes totaled 7,921. Of these, 7,542 (95 percent) were properly classified by the computer. The total computer count was 8,717, representing a 13 percent false positive and 5 percent false negative identification rate. The false positive identifications of premature ventricular complexes occurred during periods of 10 seconds or more of continuous noise artifact and in the presence of atrial premature complexes conducted aberrantly. When these sections of tape were excluded, the computer had a less than 2 percent false negative and 3 percent false positive rate of identification of premature ventricular complexes.
Athletes, nonsteroidal anti-inflammatory drugs, coxibs, and the gastrointestinal tract

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most common self-administered and prescribed drugs taken in the United States. From 30% to 50% of those using these medications experience some degree of gastrointestinal (GI) side effect. Independent of NSAID use, a majority of athletes suffer GI symptoms, most of which has been documented in endurance athletes. Studies of NSAID use in patients with chronic osteo- and rheumatoid arthritis have defined a set of factors that can identify those who are at higher risk of serious GI events. Using such a model, clinicians can choose either to discontinue NSAID use, or prescribe a lower-risk NSAID or coxib (rofecoxib, celecoxib), prophylaxis with misoprostol, or proton pump inhibitor. Coxibs have been designed to decrease GI ulceration and bleeding by selective inhibition of cyclooxygenase-2, and offer an option for patients at high risk of GI hemorrhage. There are data suggesting that rofecoxib may be associated with an increased risk of myocardial infarction, and until further data are available, caution should be used when considering its prescription to patients at high risk of cardiovascular events.
Consumer Reactions to Explicit Brand Comparisons in Advertisements

The relative influence of comparative and noncomparative advertising on purchase intention ratings, perceptions of believability, credibility, quantity of information, and usefulness of information...
Self-consistent molecular dynamics formulation for electric-field-mediated electrolyte transport through nanochannels.

A self-consistent molecular dynamics (SCMD) formulation is presented for electric-field-mediated transport of water and ions through a nanochannel connected to reservoirs or baths. The SCMD formulation is compared with a uniform field MD approach, where the applied electric field is assumed to be uniform, for $2\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ and $3.5\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ wide nanochannels immersed in a $0.5M$ KCl solution. Reservoir ionic concentrations are maintained using the dual-control-volume grand canonical molecular dynamics technique. Simulation results with varying channel height indicate that the SCMD approach calculates the electrostatic potential in the simulation domain more accurately compared to the uniform field approach, with the deviation in results increasing with the channel height. The translocation times and ionic fluxes predicted by uniform field MD can be substantially different from those predicted by the SCMD approach. Our results also indicate that during a $2\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$ simulation time ${\mathrm{K}}^{+}$ ions can permeate through a $1\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ channel when the applied electric field is computed self-consistently, while the permeation is not observed when the electric field is assumed to be uniform.
Coordination of Dimethyl Methylphosphonate to the Bidentate Lewis Acid 1,2-Bis(chloromercurio)tetrafluorobenzene

Incremental addition of the nerve gas simulant dimethyl methylphosphonate (DMMP) to an acetone solution of the bidentate Lewis acid 1,2-bis(chloromercurio)tetrafluorobenzene results in a downfield shift of the 199Hg NMR resonance. This phenomenon is explained by the formation of a complex involving the bifunctional Lewis acid and DMMP with a stability of 3.7 (±0.4) M-1. Upon cooling of a hot solution of 1,2-bis(chloromercurio)tetrafluorobenzene in neat DMMP, needlelike crystals of a 1:2 complex are formed. This compound has been characterized by IR, 31P{1H} CP/MAS NMR, elemental analysis, and X-ray single-crystal analysis. The structural data show that the phosphoryl oxygen atom of each DMMP bridges the two mercury centers of the bidentate Lewis acid. The individual adduct molecules interact by intermolecular Hg···Cl contacts, which leads to the formation of polymeric chains. Each chain interacts with two neighboring chains via formation of offset π−π contacts. These weak interactions result in the format...
Influence of zirconium salt precursors on the crystal structures of zirconia

Procedures have been developed for preparing zirconia to yield either tetragonal or monoclinic phases following low (400–600 °C) temperature calcination. The data in this note emphasize the need for paying attention to the precursor zirconium salt in preparing the monoclinic or tetragonal phases. A salt precursor obtained from a supplier at different times may produce different results. Generally, it is more difficult to obtain a precursor that will produce the monoclinic phase than the one that will produce the tetragonal form.
Low-temperature bitumen stiffness and viscous paraffinic nano- and micro-domains by cryogenic AFM and PDM

In an effort to better understand the structure and behaviour of bitumen in low temperature, we describe the first use of cryogenic atomic force microscopy and phase detection microscopy to characterize bitumen nano- and micro-structures. The results were interpreted in light of glass transition temperatures (T(g)s) for bitumen fractions. The domains visible by microscopy, the catana, peri and para phases, were attributed to domains rich in asphaltenes, naphthene and polar aromatics, and saturates, respectively. Between -10 degrees C and -30 degrees C, atomic force microscopy images revealed topographic features not visible in atomic force microscopy images acquired at room temperature. According to phase detection microscopy and T(g)s, the features were assigned to viscous unfrozen saturates. Upon cooling to -72 degrees C, unfrozen domains of 20-400 nm were observed. These domains were found in the paraphase rich in saturates and in the periphase rich in naphthene aromatics and polar aromatics. The findings indicate that new viscous domains form upon cooling to low temperatures owing to phase segregation, and that some bitumens are never entirely rigid in low temperatures.
Control of Tetrahedral Coordination and Superconductivity in FeSe0.5Te0.5 Thin Films

We demonstrate a close relationship between superconductivity and the dimensions of the Fe-Se(Te) tetrahedron in FeSe0.5Te0.5. This is done by exploiting thin film epitaxy, which provides controlled biaxial stress, both compressive and tensile, to distort the tetrahedron. The Se/Te height within the tetrahedron is found to be of crucial importance to superconductivity, in agreement with the scenario that (π, π) spin fluctuations promote superconductivity in Fe superconductors.
Activation of BlaR1 protein of methicillin-resistant Staphylococcus aureus, its proteolytic processing, and recovery from induction of resistance

The fates of BlaI, the gene repressor protein for the bla operon, BlaR1, the β-lactam sensor/signal transducer, and PC1 β-lactamase in four strains of Staphylococcus aureus upon exposure to four different β-lactam antibiotics were investigated as a function of time. The genes for the three proteins are encoded by the bla operon, the functions of which afford inducible resistance to β-lactam antibiotics in S. aureus. BlaR1 protein is expressed at low copy number. Acylation of the sensor domain of BlaR1 by β-lactam antibiotics initiates signal transduction to the cytoplasmic domain, a zinc protease, which is activated and degrades BlaI. This proteolytic degradation derepresses transcription of all three genes, resulting in inducible resistance. These processes take place within minutes of exposure to the antibiotics. The BlaR1 protein was shown to undergo fragmentation in three S. aureus strains within the time frame relevant for manifestation of resistance and was below the detection threshold in the fourth. Two specific sites of fragmentation were identified, one cytoplasmic and the other in the sensor domain. This is proposed as a means for turnover, a process required for recovery from induction of resistance in S. aureus in the absence of the antibiotic challenge. In S. aureus not exposed to β-lactam antibiotics (i.e. not acylated by antibiotic) the same fragmentation of BlaR1 is still observed, including the shedding of the sensor domain, an observation that leads to the conclusion that the sites of proteolysis might have evolved to predispose the protein to degradation within a set period of time.
Acute postnatal cataract formation in Smith-Lemli-Opitz syndrome

We report on two patients with severe Smith-Lemli-Opitz syndrome who acutely developed postnatal cataracts. These postnatal cataracts appear to be due to a different pathological mechanism and have a different clinical course than the typical congenital cataracts that occur in SLOS. The rapid development of these cataracts suggests that dysfunction or rupture of the lens capsule leading to acute osmotic shifts contributes to their formation. In addition, cataract formation in these patients was associated with conjunctival injection, fibrotic irido-lenticular adhesions, and capsular fibrosis. These findings are suggestive an inflammatory component that is consistent with impaired competence of the lens capsule.
Mutations in the Tetrahymena Ribozyme Internal Guide Sequence: Effects on Docking of the P1 Helix into the Catalytic Core and Correlation with Catalytic Activity†

Binding of substrate by the ribozyme derived from the self-splicing intron of Tetrahymena thermophila involves at least two steps. In the first step, base pairing between the ribozyme internal guide sequence (IGS) and the substrate forms a helical duplex (P1). Through specific tertiary interactions between P1 and the ribozyme core, P1 is then docked into the ribozyme active site. We have investigated the effects of compensatory mutations in positions 2-6 of the P1 helix on docking of P1 into the ribozyme core. Equilibrium binding of matching oligonucleotides by catalytically active IGS mutant ribozymes was evaluated by gel-shift analysis. While the strength of base pairing changed with base composition as expected, the strength of tertiary interactions between P1 and the ribozyme core was not affected by the P1 mutations. These results support a model in which efficient docking of P1 is determined by P1 structure and the presence of a conserved G-U pair. Determination of the rate of dissociation of matching oligonucleotides from each ribozyme revealed that mutations in the IGS change the tightness of binding by increasing or decreasing the dissociation rate. Surprisingly, dissociation rates determined in this fashion were 20-900-fold less than the values of the multiple-turnover rate constant for these ribozymes, initially suggesting that turnover did not require product dissociation. A more detailed analysis for the wild-type ribozyme defined two distinct product dissociation rates. The slower rate equaled that determined under the conditions used for the equilibrium binding studies. The weighted average of the two dissociation rates equaled the multiple-turnover rate constant. These results are explained by a model in which ribozyme preparations consist of two ribozyme conformers: one with tight docking of P1 and another with weaker docking of P1.
Pharmacokinetic Analysis of Oral Doxycycline in Rhesus Macaques

Background Following administration of an antibiotic, the concentration in blood changes over time and is dependent on the type of antibiotic, the route and species of the individual. The most relevant pharmacodynamic property of a bacteriostatic antibiotic such as doxycycline is the minimum inhibitory concentration (MIC), whereas pharmacokinetics may include rates of absorption and elimination from blood. Methods We determined serum concentrations of doxycycline following administration of 5 mg/kg in two macaques. Results The area under the concentration–time curve over 24 hours (AUC0–24) following two doses was extrapolated from the curve over 12 hours following a single dose, with the purpose of calculating the AUC0–24:MIC. Conclusions Other than a somewhat faster rate of elimination, the PK-PD values for doxycycline in macaques appears similar to those determined for humans. This information will be valuable for treating disease in macaques and for research in bacterial infection models that use macaques.
Ego's important discussants or significant people: an experiment in varying the wording of personal network name generators ☆

Abstract There is considerable disagreement about the best personal network name generator to employ when only a single question is practical. One general approach is to ask the respondents (egos) to delineate the core members (alters) of their personal networks according to affective criteria (e.g., “the most significant people in your life”). Another approach provides more guidance to the egos by asking about alters with whom they have had specific interactions or social exchanges (e.g., “discuss important matters”). Finally, most name generators have been criticized for their preoccupation with positive ties to the exclusion of the difficult or negative relationships that may be an important part of ego's social world. An experiment (2×2 factorial design) was embedded within an interviewer-administered survey of 426 college students to explore the effects on reported network size and composition of (a) varying the delineation criteria (“significant people” or the 1985 General Social Survey (GSS) “important matters”) and (b) including or excluding a probe for negative interactions (“These may include people that sometimes make you angry or upset”). The name-generator wording manipulations produced modest network compositional differences (ego–alter role relationships and discussion topics) that varied by the sex of both egos and their alters. Compared to the “important matters” criterion, the “significant people” generator elicited slightly more cross-sex relatives and fewer same-sex close friends and co-workers from female (but not male) respondents. The negative probe produced some statistically significant but substantively unimportant compositional differences. The results suggest that major differences in name-generator wording may in some situations have little or no effect on reported egocentric networks.
Topic: A Literature Review

There is a wide discussion for Chinese topic structure and topic-sentence acquisition in Second Language Acquisition since Li & Thompson (1976). This paper reviews the contribution made by Li & Thompson on topic and later researches on the basis of them. The relationship between subject and topic also is concentrated.
Biological Synthesis of a Growth Factor for Mammalian Cells in Tissue Culture.

SummaryA non-dialyzable substance was recovered in crude form from growth fluid of mouse lung fibroblasts adapted to a serum-free medium. This substance was capable of replacing the serum protein normally required for human liver cell growth. The substance in the material from mouse lung cell growth fluid is heat labile. The crude material was heat coagulable with loss of growth promoting activity for human liver cells. A graded dose response of growth of liver cells was obtained.
The impact of exchange rate volatility on commodity trade between the US and Thailand

The impact of exchange rate volatility on trade flows continues to occupy the international finance literature. More recent studies have deviated from the traditional approach of using aggregate trade flows and have employed trade data at commodity level. This study investigates the impact of exchange rate uncertainty on the trade flows of 118 US exporting industries to Thailand and 41 US importing industries from Thailand. We find that exchange rate uncertainty has short-run effects on the trade flows of most industries. In the long-run, the main determinants of the trade flows are the level of economic activity in both countries.
Spectroscopic far ultraviolet observations of transition zone instabilities and their possible role in a pre-flare energy build-up.

(1) Highly flare-productive new emerging active regions are characterized by numerous small low-lying loops which frequently show a chaotic pattern. (2) Flare activity in such a region subsides as the chaotic loop structures relax and expand into a bipolar configuration. (3) The transition zone in such an active region is highly unstable as shown by broadened and shifted non-thermal line profiles of medium ionized elements like Si iii, Si iv, C iv, etc. (4) These transition zone instabilities which occur as isolated events in active regions of low flare productivity are often observed prior to flares. (5) Transition zone instabilities can be traced to the footpoints of active loops, and seem to be accompanied by heating of the loop. (6) The loops vary in size and show differing degrees of activity, with the brightest and most compact ones seemingly being in a pre-flare state which results in the catastrophic energy release along the loop during a flare.
Effect of melt spinning on the structure and superconducting transition temperature of “Nb3Si” alloys

Abstract Melt spinning with a sample suspension device was used to rapidly solidify Nb-Si alloys ranging from 18 to 24 at% Si. Amorphous ductile ribbons were obtained for all of the above compositions; the superconducting transition temperatures T c were 4.0 to 4.4 K. Furthermore, by accurate control of the quenching rates, metastable A-15 crystallites embedded in an amorphous matrix were obtained; the ribbons were semi-ductile and T c onset of the A-15 phase was 5.6 K.