cssi/SciSciGPT-SciSciNet huggingface dataset:
Dry film process development for electroplating and lift-off of metal layers

A dry film photoresist (MX 5020 from DuPont Electronic Technologies) was selected to fabricate microstructures with high sidewall verticality. Sidewall verticality of dry film is very important for better pattern transfer and sharp features. A fractional factorial design (FFD) method was used to identify the significant process variables for sidewall optimization. The most significant factor was determined to be exposure energy, as other factors were not significant in improving sidewall verticality. It was found that the sidewall slope increased with a decrease in exposure energy. The fabricated dry film molds with nearly vertical sidewalls (86°) were used for copper electroplating and sputter deposited Ti lift-off applications. The electroplating process was also optimized using a fractional factorial design. A lower plating current density resulted in a smoother, fine grained deposit compared to the higher current density, and the dry film resist was able to withstand a very acidic (pH ~1) copper sulfate plating solution. Sputtered titanium films with a thickness of 200 nm were also successfully lifted-off using dry film patterning.
The gas-phase chemistry of metal and metal-containing ions with multifunctional organic molecules—investigating the utility of such ions as chemical-ionization reagents

Abstract Ion/molecule reactions of electron-impact-induced fragment ions of Co(CO) 3 NO with 2-chloroethanol, 3-chloro-2-butanone and allyl-X (X = -NH 2 , -Cl, -Br, -OH, -OC 3 H 5 ) are reported. The results indicate that the allyl compounds react similarly with Co + as do their saturated analogs, but as the number of ligand on the Co + ion increases new reactions are observed which are explained by ligand interactions. The use of metal-containing ions as chemical-ionization reagents for bifunctional organic compounds has also been investigated. The results indicate that the interpretation may be simple if each functional group reacts individually, such as in chlorobutanone, or may not be as simple if the two groups behave as one “new group”, as in 2-chloroethanol.
Effect of ionizing radiation on the development of photosynthesis in etiolated wheat leaves.

Abstract Doses of gamma radiation as high as 150 kr. delayed the greening of etiolated wheat plants in the light by as much as 10 hr. The irradiated plants developed a complete photosynthetic mechanism, as determined by C 14 O 2 incorporation into normal products. The inhibition of greening caused by gamma radiation could be overcome by exposure to white light, but was not changed after 24 hr. in the dark. Conversion of protochlorophyll to chlorophyll was not affected by gamma radiation. The normal lag between the beginning of sustained chlorophyll synthesis and the development of photosynthetic CO 2 fixation did not occur after gamma radiation.
Nanometer-Size Conducting and Insulating Molecular Devices

Using quantum ab initio techniquesa theoretical “microscope”we demonstrate that molecules of nanometer sizes can be characterized as low and high impedance devices, needed as building blocks in the field of molecular electronics. Small alkanes and polyynes chains with σ and π bonding, respectively, yield a high-low impedance relation of 2 orders of magnitude at 1-nm length and of 3 orders of magnitude at 1.3-nm length. For these small chains, it is concluded that no simple trends of conductance versus length can be determined. We also successfully test our methods against a recent precise experiment.
A redistribution method for axisymmetric diffusion

We develop grid-free numerical procedures to compute axisymmetric incompressible flows. In particular, we formulate a grid-free redistribution method' to handle diffusion processes accurately on a disordered collection of computational elements. We validate the numerical procedures by computing the Stokes flow and the Navier-Stokes flow of a vortex ring.
Half-sandwich ruthenium–arene complexes with thiosemicarbazones: Synthesis and biological evaluation of [(η6-p-cymene)Ru(piperonal thiosemicarbazones)Cl]Cl complexes

The synthesis and characterization of a number of organometallic ruthenium(II) complexes containing a series of bidentate thiosemicarbazone ligands derived from piperonal is reported. The structure of compounds have been confirmed by spectroscopic analysis (IR and NMR) as well as X-ray crystallographic analysis of [(η 6 - p -cymene)Ru(pPhTSC)Cl]Cl ( 4 ) (pPhTSC is piperonal-N(4)-phenylthiosemicarbazone). The interaction of the complexes ([(η 6 - p -cymene)Ru(pEtTSC)Cl]Cl) ( 3 ) (pEtTSC is piperonal-N(4)-ethylthiosemicarbazone) and 4 with calf thymus DNA, human serum albumin (HSA) and pBR322 plasmid DNA were studied by spectroscopic, gel electrophoresis and hydrodynamic methods. The apparent binding constant for the interaction with DNA was determined to be 3.97 × 10 3 M − 1 and 4.07 × 10 3 M − 1 at 293 K for 3 and 4 respectively. The complexes bind strongly to HSA with binding constants of 2.94 × 10 4 M − 1 and 12.2 × 10 4 M − 1 at 296 K for 3 and 4 respectively. The in vitro anticancer activity of 3 and 4 has been evaluated against two human colon cancer cell line (HCT-116 and Caco-2) with IC 50 values in the range of 26–150 μM. Both 3 and 4 show good activity as a catalytic inhibitor of human topoisomerase II at concentrations as low as 20 μM. The proficiency of 3 and 4 to act as antibacterial agents was also evaluated against six pathogenic bacterial strains with the best activity seen against Gram-positive strains.
Prevalence and predictors of asymptomatic liver disease in patients undergoing gastric bypass surgery.

Background Nonalcoholic steatohepatitis (NASH) is a form of fatty liver disease that is increasingly recognized. There are limited data on the prevalence of NASH and the role of risk factors for NASH among the morbidly obese. Hypothesis The prevalence of asymptomatic NASH among morbidly obese patients undergoing gastric bypass surgery is high, and there are identifiable risk factors for NASH. Design Prospective case study. Setting University hospital. Patients Forty-eight consecutive patients undergoing gastric bypass surgery who had a concurrent open liver biopsy. Exclusion criteria included current consumption of more than 2 alcohol beverages monthly and known cirrhosis. A hepatopathologist blinded to clinical data reviewed biopsy specimens. Main Outcome Measures The presence of NASH or severe fibrosis, preoperative body mass index (BMI) (calculated as weight in kilograms divided by the square of height in meters), fasting triglyceride level, and presence of type 2 diabetes mellitus (DM). Results Patients (mean ± SD age, 42 ± 10 years; 33 women) had an initial mean BMI of 59.9 ± 12. Thirty-one patients (65%) had moderate to severe steatosis. Only 6 (12%) had advanced fibrosis. Sixteen (33%) had evidence of NASH. There was no difference in mean age, sex, BMI, or fasting triglyceride level between patients with and without NASH or advanced fibrosis. The odds of NASH were 128 times greater (95% confidence interval [CI], 5.2-3137.0) and the odds of severe fibrosis 75 times greater (95% CI, 4.5-1247.0) in patients with DM than in those without DM. Preoperative BMI was not independently associated with NASH (odds ratio, 1.01; 95% CI, 0.9-1.1) or severe fibrosis (odds ratio, 0.9; 95% CI, 0.86-1.02) after adjustment for DM. Conclusions Moderate to severe hepatic steatosis and NASH are common among individuals undergoing gastric bypass procedures. Diabetes mellitus but not BMI is associated with NASH and advanced hepatic fibrosis in these patients.
The Microstructure of Transition Metal/Al(Cu) Layers

Etude par microscopie electronique en transmission des microstructures Hf/Al-0 a 9% Cu et Ti/Al-0 a 9% Cu. Influence d'un recuit et de la teneur en cuivre sur la structure des grains et sur la morphologie de l'interface
Improving energy efficiency for mobile platforms by exploiting low-power sleep states

Reducing energy consumption is one of the most important design aspects for small form-factor mobile platforms, such as smartphones and tablets. Despite its potential for power savings, optimally leveraging system low-power sleep states during active mobile workloads, such as video streaming and web browsing, has not been fully explored. One major challenge is to make intelligent power management decisions based on, among other things, accurate system idle duration prediction, which is difficult due to the non-deterministic system interrupt behavior. In this paper, we propose a novel framework, called E2S3 (Energy Efficient Sleep-State Selection), that dynamically enters the optimal low-power sleep state to minimize the system power consumption. In particular, E2S3 detects and exploits short idle durations during active mobile workloads by, (i) finding optimal thresholds (i.e., energy break-even times) for multiple low-power sleep states, (ii) predicting the sleep-state selection error probabilities heuristically, and by (iii) selecting the optimal sleep state based on the expected reward, e.g., power consumption, which incorporates the risks of making a wrong decision We implemented and evaluated E2S3 on Android-based smartphones, demonstrating the effectiveness of the algorithm. The evaluation results show that E2S3 significantly reduces the platform energy consumption, by up to 50% (hence extending battery life), without compromising system performance.
Student Self-Prediction of Academic Achievement

Increased use of student judgment of achievement for grading purposes presupposes student ability to supplement or supplant traditional systems based on test data. This assumption was tested using ...
Clinical experience and laboratory investigations in patients with anti-NMDAR encephalitis

Since its discovery in 2007, the encephalitis associated with antibodies against the N-methyl-D-aspartate receptor (NMDAR) has entered the mainstream of neurology and other disciplines. Most patients with anti-NMDAR encephalitis develop a multistage illness that progresses from psychosis, memory deficits, seizures, and language disintegration into a state of unresponsiveness with catatonic features often associated with abnormal movements, and autonomic and breathing instability. The disorder predominantly affects children and young adults, occurs with or without tumour association, and responds to treatment but can relapse. The presence of a tumour (usually an ovarian teratoma) is dependent on age, sex, and ethnicity, being more frequent in women older than 18 years, and slightly more predominant in black women than it is in white women. Patients treated with tumour resection and immunotherapy (corticosteroids, intravenous immunoglobulin, or plasma exchange) respond faster to treatment and less frequently need second-line immunotherapy (cyclophosphamide or rituximab, or both) than do patients without a tumour who receive similar initial immunotherapy. More than 75% of all patients have substantial recovery that occurs in inverse order of symptom development and is associated with a decline of antibody titres. Patients' antibodies cause a titre-dependent, reversible decrease of synaptic NMDAR by a mechanism of crosslinking and internalisation. On the basis of models of pharmacological or genetic disruption of NMDAR, these antibody effects reveal a probable pathogenic relation between the depletion of receptors and the clinical features of anti-NMDAR encephalitis.
Recognition based separation of HIV-Tat protein using avidin–biotin interaction in modified microfiltration membranes

Recognition based separation using modified microfiltration membranes provides an efficient and cost-effective alternative to conventional column chromatography for the separation and purification of a specific protein from mixture of proteins. In this study, Tat protein, which has been proposed as the specific target for AIDS vaccine, was separated and purified from a complex mixture of proteins, known as bacterial lysate (BL) using avidin–biotin interaction in 4-stack microfiltration membranes system. It was established by SDS-PAGE and Western Blot analysis that membrane based process recovered more pure form of Tat compared to conventional packed-bead column chromatography. The critical factors involved in the process, mainly, the accessibility of the covalently immobilized avidin sites by the biotinylated protein and the associated fouling of the membranes due to the permeation of proteins, were also studied. The accessibility of immobilized avidin sites in membrane was quantified by biotinylated solutions of different types and compositions. It was observed that permeation of proteins caused substantial fouling on the membrane matrix. The resistance offered by the protein layer and the approximate thickness of the protein layer were also quantified.
Mimicked in-situ stabilization of metals in a cropped soil : Bioavailability and chemical form of zinc

Agricultural lime, natural zeolite (clinoptilolite), hydroxyapatite, and an iron oxide waste byproduct (Fe-rich, a trademark name of E.I. du Pont de Nemours) were added to an artificially contaminated Applying silt loam soil to stabilize and limit the uptake of Zn by crops. A greenhouse pot study involves spiking the soil with flue dust FD at 0, 150, 300, 600, 1200, and 2400 mg of Zn kg{sup -1}. As much as 40% of the total Zn occurred in an exchangeable form, the form considered most bioavailable to plants, when the pH of the FD-spiked soil was below 6.0. The ameliorants (lime, zeolite, apatite, and Fe-rich) decreased the concentration of the exchangeable form of Zn at each level of FD in soil; however, the largest decrease occurred with the lowest dose. Maize (Zea mays), barley (Hordeum vulgare), and radish (Raphanus sativus) were growth to determine the effects of Zn on the plant growth and its uptake. The addition of ameliorants to soil enhanced the growth and yield of maize and barley, but only Fe-rich enhanced the growth of radish at all FD rates. Lime, zeolite, and apatite significantly reduced the Zn concentration in tissues of the 3-week-old maize, in mature maize tissuesmore » (roots, young leaves, old leaves, stems, grain), and in barley. The largest reduction (over 80%) in Zn uptake by all crops was effected by Fe-rich, which is consistent with the greatest reduction in soil-exchangeable Zn by this ameliorant. 44 refs., 4 figs., 7 tabs.« less
Phylogeography and systematics of the Peromyscus eremicus species group and the historical biogeography of North American warm regional deserts.

Phylogeographic relationships among 26 populations from throughout the geographic range of the Peromyscus eremicus species group are described based on sequence data for a 699-bp fragment of the mitochondrial DNA COIII gene. Distance, maximum-likelihood, and maximum-parsimony analyses of phylogenetic trees generated under four separate character-weighting strategies and representing five alternative biogeographic hypotheses revealed the existence of a cryptic species (Peromyscus fraterculus, previously included under P. eremicus) on the Baja California Peninsula and adjacent southwestern California and two distinct forms of P. eremicus, one from the Mojave, Sonoran, and northwestern Chihuahuan regional deserts (West) and one from the remainder of the Chihuahuan Desert (East). Distinctiveness of P. fraterculus is supported by previous morphometric and allozyme analyses, including comparisons with neighboring P. eremicus and parapatric P. eva, with which P. fraterculus shares a sister taxon relationship. Divergence of the eva + fraterculus, West + East eremicus, and P. merriami haplotype lineages likely occurred in the late Neogene (3 Ma), in response to northern extension of the Sea of Cortez and elevation of the Sierra Madre Occidental; divergence of eva from fraterculus is concordant with the existence of a trans-Peninsular seaway during the Pleistocene (1 Ma); and divergence of West from East eremicus occurred during the Pleistocene pluvial-interpluvial cycles, but well before the Wisconsinan glacial interval. The sequence of divergence within the eremicus species group and causal association of geological events of the Neogene and Holocene provide a working hypothesis against which phylogeographic patterns among other arid-adapted species of the warm regional deserts of North America may be compared.
THE EFFICACY OF TAILORED TESTING

(1969). THE EFFICACY OF TAILORED TESTING. Educational Research: Vol. 11, No. 3, pp. 219-222.
The co-degree density of the Fano plane

It is shown that every n vertex triple system with every pair of vertices lying in at least (1/2+o(1))n triples contains a copy of the Fano plane. The constant 1/2 is sharp. This is the first triple system for which such a (nonzero) constant is determined.
ULTRASONOGRAPHY OF GASTROINTESTINAL FOREIGN BODIES

The ultrasonographic findings of fourteen animals having gastrointestinal foreign bodies are presented. Ultrasonography confirmed the presence and location of foreign material within the gastrointestinal tract when radiographic findings were unclear. The acoustic patterns arising from each foreign body varied depending on its physical properties and interaction with the ultrasound beam. These patterns, some of which seemed characteristic for certain types of foreign bodies, and the associated findings of mechanical ileus, ascites, mesenteric lymph node enlargement and localized pancreatitis are discussed.
Protection from radiation‐induced chromosomal aberrations by the nitroxide tempol

Background. The nitroxide Tempol (4-hydroxy2,2,6,6-tetramethylpiperidine-1-oxyl) is a stable, free radical that exhibits protection from ionizing radiation damage and from oxidative stress mediated through exposure of cells to superoxide or hydrogen peroxide. Radiation protection has been observed in both in vivo and in vitro models. To understand the mechanism of Tempol-mediated radioprotection better, the production of radiation-induced chromosome aberrations was evaluated. This study analyzed Tempol-mediated radioprotection of human peripheral blood lymphocytes (PBLs). Methods. Peripheral blood lymphocytes were exposed to control (omM), 10 mM (Tpl0), and 50 mM (Tp50) concentrations of Tempol for 20 minutes before irradiation with 0, 150, 300, and 450 cGy. One quarter ml whole blood was cultured in F12 medium and phytohemagglutinin at 37°C for 49, 54, 59, and 64 hours. Colcemide was added to each sample for the last 5 hours before harvest. Cells were harvested, treated with hypotonic solution, and fixed before dropping on cold clean slides. Mitotic indices and frequency of dicentric, ring, and triradial chromosomal aberrations were determined at 1000X magnification for each treatment group at each collection point. Results. Treatment of cells with Tempol alone did not induce the chromosomal aberration frequency above that for unirradiated controls. Radiation dose response curves for total chromosome aberration production revealed radioprotection for Tempol treatment for both 10 and 50 mM exposures. Tempol protection factors (assessed at 0.2 aberrations/cell level) for Tp 10 and Tp 50 were 2.2 and 2.8, respectively. Conclusions. Tempol protects against radiation-induced chromosome aberrations in human PBLs. This finding is consistent with and lends support to previous studies in which Tempol was reported to enhance cell survival and reduce radiation-induced DNA double strand breaks Cancer 1995 ; 75 :2323-7.
An Inside Step in an Aerial Bucket Reduces Postural Instability During Ingress and Egress

The objective of this research study was to determine if an inside step in an aerial bucket reduces instability of a person entering and exiting the aerial bucket by reducing muscular exertion, which in theory can help reduce the risk of a fall. There are no publications based on laboratory or field studies regarding how the design of an aerial bucket affects postural instability and the risk of falls. Three configurations of aerial buckets (2 inside step locations and no inside step) for ingress and egress were tested to determine if the presence, and also the location, of an inside step affected three indicators of postural instability: location of person’s center of mass (CM), hand force on the bucket rim, and EMG activity of the triceps and rectus femoris (quadriceps). Sixteen electric utilities workers were tested. It was found that the presence of an inner step allowed for a lower CM of the person entering and exiting the bucket, reduced the muscle activity of the triceps and rectus femoris, and dec...
The differential use of monocular and binocular cues to depth in the perception of two trapezoid illusions

Twenty-four male and 24 female subjects were exposed to two dynamic trapezoid illusions under conditions of binocular and monocular regard. Distance and cues to perspective were also varied and the results on these two parameters were consistent with past research. In general, monocular regard resulted in significantly more illusory experiences than binocular regard. Binocular regard was not universally facilitating to veridical perception and, in fact, was detrimental for one-third of the subjects. There was strong evidence, moreover, that the effect of binocular cues was dependent on the particular illusion involved.
Role of endothelin in the exercise intolerance of chronic heart failure

Abstract In conclusion, plasma levels of the endothelialderived vasoconstrictor endothelin-1 (but not those of other neurohormonal vasoconstrictor factors), measured during exercise correlated closely with objective variables of exercise capacity in patients with heart failure. These findings suggest that endothelin-1 may contribute to exercise intolerance in patients with heart failure, perhaps by limiting the ability of the peripheral vasculature to dilate during exercise.
Cervical myelopathy due to dural compression in mucopolysaccharidosis

A patient with an unusual mixed mucopolysaccharidosis developed cervical myelopathy secondary to compression from a thickened dura mater. Extensive preoperative evaluation was carried out to help anticipate possible surgical problems. Decompression was accomplished safely and resulted in improved neurological function. An aggressive approach to patients with metabolic diseases with good prognosis is indicated.
The Decline in Southern Agricultural Output, 1860–1880

Per capita agricultural output sharply declined in the “Confederate States” between 1860 and 1880. This article asserts that the decline in agricultural output was partially the result of increased disease (hookworm) brought about by substandard living conditions suffered by the Southern population during the Civil War. Skeletal remains and mortality data, ubiquitous hookworm symptoms among the Southern population, and regression analysis support this hypothesis. The econometric results strongly suggest that emancipation and increased hookworm infection were responsible for the income decline while an increase in the percentage of sharecropping tenancy arrangements increased southern productivity.
Oxidation of chlorinated ethanes

The photooxidation study was undertaken to gain an understanding of the chemistry of conversion of the chlorinated ethanes to intermediate and final oxidation products. In the study, 10 ppm of each chlorinated ethane and 4 ppm of chlorine were irradiated with ultraviolet light. Three quarters of the lamps used were ''black light'' with a maximum intensity near 3650 A, while the remaining one quarter were ''sun lamps'' with 3100 A maximum intensity. A Fourier Transform spectrometer and a path length of 360 m were used to analyze the reactants and products. Chlorine atoms produced by the photolysis of molecular chlorine initiated the oxidation of each chlorinated ethane. Chlorinated products that formed during the oxidation of the chlorinated ethanes include phosgene, COCl/sub 2/; formyl chloride, HCOCl; hydrogen chloride, HCl; acetyl chloride; CH/sub 3/COCl; chloroacetyl chloride, CH/sub 2/ClCOCl; dichloroacetyl chloride, CHCl/sub 2/COCl; and trichlorocetyl chloride, CCl/sub 3/COCl. Mechanisms are proposed for the formation of these reaction products but are by no means conclusive and warrant further study. Many of the products will be further attacked in the atmosphere to produce HCl, CO/sub 2/, and CO. Hydrogen chloride will probably be washed out of the troposphere by rain but when it is formedmore » at higher altitudes it could persist and enter into the ozone destruction cycle. It is most important that information be obtained on the chemical and physical removal process for phosgene, formyl chloride, and acid chlorides. Of the chlorinated ethanes, methyl chloroform is the least reactive to atmospheric process whereas the 1,1-dichloroethane will likely be the most reactive.« less
Storable near-infrared chemiluminescent probes for in vivo optical imaging

A new class of chemiluminescent and fluorescent dyes and dye-doped nanoparticles can be stored at zero degrees and then made to emit near-infrared light by warming to body temperature (no chemical or electrical stimulus is needed). In vivo chemiluminescence imaging permits identification of target sites that are five times deeper than planar fluorescence imaging. A new imaging paradigm employs the dual modality probes first in high contrast chemiluminescence mode to locate relatively deep anatomical locations in vivo and subsequently in fluorescent mode to identify the microscopic targets within thin histopathology sections taken from the same specimen.
A computer control algorithm for feedback composition control using off-line analysis

Abstract A tunable feedback control algorithm is developed for a first-order plus dead time process which has a variable sample interval and a variable dead time. This variable sample interval, variable dead time (VSIVDT) controller is applied to controlling the product composition of a blender using off-line composition analysis. The blender and controllers are simulated using the IBM Real-Time Process Management System/Advanced Control System (RTPMS/ACS). The VSIVDT controller performed better than an alternative controller based on the Dahlin algorithm which uses off-line analysis. When compared to controllers using on-line analysis, it performed as well as a PI controller but not as well as a controller using the Dahlin algorithm.
The Formation of Linear Polymers from Diene Monomers by the Cyclopolymerization Mechanism. X. Polymers Containing Cyclohexamethylenesilyl and Cycloheptamethylenesilyl Ring Structures

Abstract In an effort to determine the feasibility of formation of larger rings from dialkenyl silanes by the cyclopolymerization mechanism through use of Ziegler-type initiators, four new silane monomers were synthesized and their polymerization studied. Allyldimethyl-(3-butene-1)-silane (I) and allyldiphenyl-(3-butene-1)-silane (III) are functionally capable of producing polymers containing a seven-membered ring. Dimethyl-bis-(3-butene-1)-silane (II) and diphenyl-bis-(3-butene-1)-silane (IV) are functionally capable of producing polymers containing an eight-membered ring. The diphenyl monomers gave benzene-soluble, solid polymers containing a low degree of residual unsaturation, interpreted as evidence that the predicted cyclization had occurred. The dimethyl derivatives, on the contrary, gave only viscous oils or semisolid products which could not be well characterized.
Legal rules as a source of comparative advantage: A case study of telecommunication equipment interconnection

Abstract Legal rules governing the interconnection of customer-premises equipment (CPE) to the telephone network have economic implications for both producers and users of such equipment. The United States instituted a free-interconnection policy between 1968 and 1976; Canada, Japan, and the United Kingdom adopted similar policies in the 1980s. A free-interconnection policy can impose costs on domestic producers as a result of increased competition among both foreign and domestic producers, but it can also provide benefits to domestic users who gain access to the world market in CPE. Interconnection rules can therefore provide a comparative advantage to countries that adopt the most favorable policy. It is shown here that free interconnection has been a favorable policy for the United States. Costs to domestic CPE producers have been small, and benefits to large users appear to have been large, both in terms of increased product diversity and in terms of price and quality of established products. The movement toward free interconnection in other countries appears to be based on the favorable experience in the countries that have already made this change. This CPE example suggests a generalization that can be expressed in terms of the “market for regulation” concept. It is suggested that an equilibrium in this market occurs at the point of maximum benefits minus costs, as experienced by the participants in this market. This equilibrium is a “rule equilibrium.” In the case of CPE, the old equilibrium was at the no interconnection point while the new equilibrium is at the free interconnection point toward which the world is presently moving.
Interaction between DNAs on a Gold Surface

Molecular dynamics (MD) methods have been used to study the conformation of DNA and its interaction with neighboring DNAs having the same base pair (bp) composition on a flat gold surface. Most of the simulations refer to a DNA that is surrounded by six other DNAs, with the initial distance between the DNAs chosen to be 27 A to simulate high packing conditions. A six-carbon alkylthiolate linker connects each DNA to the gold surface, and there is an A10 spacer between the alkylthiolate and an 18 bp double-stranded (ds) region for each DNA. In addition, there is a 5 base dangling end on each DNA to match recent experiments in which the dangling ends appeared to show important interactions. We performed 20 ns MD simulations in water with high salt concentration, and it is found that the ds-DNA maintains Watson−Crick B-DNA conformations. The tilt angle (relative to the surface) of the central DNA in the cluster is 27° ± 5°, whereas the tilt angle of the surrounding DNAs is 11° ± 5°. The average angle between ...
Problems, Philosophy, and Motivation: Trail Blazing Instructors for the Digital Frontier

A qualitative research study was conducted of innovative instructors who use the Internet to deliver college level courses. The study focuses on key concepts expressed by all of the Pioneers as important and develops recommendations for other instructors beginning to use the Internet for instructional purposes. Results are presented on the problems encountered, the Pioneers' philosophies toward teaching and learning, and the Pioneers' motives for moving their courses to the Internet. This research is a multiple case study that used four instructors from a university in the South concerning three courses being taught over the Internet during the Spring term of 1996.
Reaction of Silver-Tin Alloys and Mercury

In dentistry one of the most important alloy systems is the ternary mercury-silver-tin system. This is the basis for dental amalgams which constitute by far the greatest percentage of dental restorations. While the dental literature is abundant with studies of the physical properties of silver-tin (copper-zinc) amalgams, little of this work has been related to the mechanism of setting and the metallurgy of the resulting amalgams. Voluminous bibliographies of practical application and techniques of usage of amalgams may be found in the standard dental textbooks.1' 2 Studies of the silver-mercury and tin-mercury systems have been carried out by many workers, and information concerning these systems now appears to be well documented.3 6 While there have also been some attempts to study the mercury-silver-tin system, these have been comparatively few in number. Joyner7 appears to have been the first to study this system. Without doubt, the most extensive study was that of Gayler,8 who was concerned primarily with the silverrich alloys of the silver-tin system (i.e., silver > 74.22 per cent). Gayler used thermal analysis and microscopy to study this system. Troiano9 has carried out an X-ray diffraction investigation, while Stenbeck'0 has attempted to correlate X-ray diffraction studies with mechanical properties. These and other more recent studies of the ternary system have been reviewed and evaluated by Ryge, Fairhurst, and Fischer1 in 1961. Previous work in this field has to a large extent been based on the consideration of
Incidence of contralateral inguinal hernia: a prospective analysis.

Abstract Background/Purpose: Contralateral groin exploration in children with unilateral inguinal hernia is still controversial, particularly in infants. The authors have attempted to determine the age- and gender-stratified incidence of contralateral hernia and the necessity of routine bilateral procedures. Methods: This is a prospective study of 656 patients during a 34-month period at a single institution. Patients with unilateral hernia underwent an ipsilateral procedure only, regardless of age, gestational age, or gender. Follow-up was 6 to 40 months (mean, 25.5 months). Chi-square analysis was used for intergroup comparison ( P Results: Of 656 children, 108 (16.5%) presented with synchronous bilateral hernias. Bilateral inguinal hernia was significantly more common in premature infants (28.0%) and young children (33.8% if P 2 analysis. Conclusion: Routine contralateral inguinal exploration, without clinical evidence of a hernia, may be advisable in children with incarceration and possible in premature infants. The low incidence of contralateral hernias in all other patients, regard-less of gender or age, does not justify routine contralateral exploration.
Grafting of poly(ethylenimine) onto mesylated cellulose acetate, poly(methyl methacrylate) and poly(vinyl chloride)

Abstract Work on the formation of graft copolymers of cellulose derivatives has been continued by grafting poly(ethylenimine) (PEI) onto mesylated cellulose acetate (MCA) by second order nucleophilic displacement (SN2) of mesylate groups by amine groups. Three solutions each containing 5% MCA and 2·5, 5 and 10% PEI, respectively, in dimethylformamide (DMF) were reacted at 80°C. The first solution did not form a gel, while the others formed gels (since cross-linking occurs) in 3 h and 1·5 h, respectively. This indicates aminolysis of acetate groups was taking place preferentially to the SN2 reaction. Reaction of PEI with poly(methyl methacrylate) (PMMA) led to gelation, indicating that aminolysis of ester groups was occurring even with the ‘hindered’ esters of PMMA. The nucleophilic reaction leading to grafting was demonstrated by reaction of PEI with poly(vinyl chloride) (PVC), which also led to gelation. These grafting reactions could be used to produce cross-linked resins with high ion-exchange capacity.
Contributions of phytoplankton and other particles to inherent optical properties in New England continental shelf waters

Variability in upper ocean optical properties is often driven by changes in the particle pool. We investigated the effects of such changes by characterizing individual particles. For particles in natural assemblages, we used a combination of Mie theory and flow cytometry to determine diameter ( D), complex refractive index (n 1 in9), and optical cross-sections at 488 nm. Particles were grouped into categories of eukaryotic pico/nanophytoplankton, Synechococcus, heterotrophic prokaryotes, detritus, and minerals to interpret variability in concurrently measured bulk inherent optical properties (IOPs) in New England continental shelf waters during two seasons. The summed contributions of individual particles to phytoplankton absorption and particle scattering were close to values for these properties measured independently using bulk methods (87% and 107%, respectively). In surface waters during both seasons, eukaryotic phytoplankton were responsible for the majority of both total particle absorption and total particle scattering. Mineral particles contributed the most to backscattering ( bb) in the spring, whereas in the summer both mineral and detrital particles were important. Synechococcus and heterotrophic prokaryotes never contributed more than 14% to IOPs. Our findings emphasize that the measurement of nonliving particles, including detritus and minerals, is necessary for understanding variability in bb in the ocean, an important quantity in the interpretation of satellite ocean color. Knowledge of particle properties is important for the interpretation of variability in the inherent optical properties (IOPs; Table 1) of the upper ocean. Models of particle IOPs will be the basis for improved algorithms for light attenuation and for deriving properties such as chlorophyll concentration from satellite ocean color. Results of previous model simulations have shown how changes in particle type can give significantly different IOPs, even at the same chlorophyll concentration (Mobley and Stramski 1997; Stramski et al. 2001). These simulations were based on assumptions about the types of particles present and the distributions of diameter (D) and complex refractive index (n 1 in9) for each particle group included in the model. Certain of these particle properties are difficult to measure, especially distributions of n and n9. By definition, n governs scattering at interfaces and n9 is related to the absorption properties of a particle. Inferences of average n for a particle assemblage have been made by a variety of optical methods, in conjunction with Mie theory (e.g., Zaneveld et al. 1974; Morel and Bricaud 1986; Stramski and Morel 1990; Twardowski et al. 2001), but detailed distributions of individual particle properties (i.e., within-group variations) cannot be determined from bulk optical approaches. One approach for determining distributions of particle properties for natural pop1 Corresponding author.
The Competitiveness of the Cuban Tourism Industry in the Twenty-First Century: A Strategic Re-Evaluation

Cuba holds great potential for competitiveness within the Caribbean regional, and even global, tourism industry. The question “Can Cuba realize this potential?” looms increasingly large across the region and within U.S. tourism interests, as Castro's health is in question and brother Raul assumes more control over the country's political economy. This article analyzes the Cuban tourism industry's current position in the context of leading current models of competitive advantage. It is concluded that, in the case of Cuba, ambitious competitive strategies have been diminished to date by less-focused execution in practice. In general, however, careful analysis of competitive positioning can provide potential for greater success of individual destinations and enhanced regional cooperation.
On the Effectiveness of Measurement Reuse for Performance-Based Detouring

For both technological and economic reasons, the default path between two end systems in the wide-area Internet can be suboptimal. This observation has motivated a number of systems that attempt to improve reliability and performance by routing over one or more hops in an overlay. Most of the proposed solutions, however, fall at an extreme in the cost-performance trade-off. While some provide near-optimal performance with an un-scalable measurement overhead, others avoid measurement when selecting routes around network failures but make no attempt to optimize performance. This paper presents an experimental evaluation of an alternative approach to scalable, performance detouring based on the strategic reuse of measurements from other large distributed systems, namely content distribution networks (CDNs). By relying on CDN redirections as hints on network conditions, higher performance paths are readily found with little overhead and no active network measurement. We report results from a study of more than 13,700 paths between 170 widely-distributed hosts over a three-week period, showing the benefits of this approach. We demonstrate that it is practical by implementing an FTP suite that uses our publicly available Side Step library to take advantage of these alternative Internet routes.
Molecular Simulation Study of the Competitive Adsorption of H2O and CO2 in Zeolite 13X

The presence of H2O in postcombustion gas streams is an important technical issue for deploying CO2-selective adsorbents. Because of its permanent dipole, H2O can interact strongly with materials where the selectivity for CO2 is a consequence of its quadrupole interacting with charges in the material. We performed molecular simulations to model the adsorption of pure H2O and CO2 as well as H2O/CO2 mixtures in 13X, a popular zeolite for CO2 capture processes that is commercially available. The simulations show that H2O reduces the capacity of these materials for adsorbing CO2 by an order of magnitude and that at the partial pressures of H2O relevant for postcombustion capture, 13X will be essentially saturated with H2O .
Exploiting frequent field values in java objects for reducing heap memory requirements

The capabilities of applications executing on embedded and mobile devices are strongly influenced by memory size limitations. In fact, memory limitations are one of the main reasons that applications run slowly or even crash in embedded/mobile devices. While improvements in technology enable the integration of more memory into embedded devices, the amount memory that can be included is also limited by cost, power consumption, and form factor considerations. Consequently, addressing memory limitations will continue to be of importance.Focusing on embedded Java environments, this paper shows how object compression can improve memory space utilization. The main idea is to make use of the observation that a small set of values tend to appear in some fields of the heap-allocated objects much more frequently than other values. Our analysis shows the existence of such frequent field values in the SpecJVM98 benchmark suite. We then propose two object compression schemes that eliminate/reduce the space occupied by the frequent field values. Our extensive experimental evaluation using a set of eight Java benchmarks shows that these schemes can reduce the minimum heap size allowing Java applications to execute without out-of-memory exceptions by up to 24% (14% on an average).
Stacking Sequence and Geometrical Effects on Low-Velocity Impact Behaviors of GLARE 5 (3/2) Fiber–Metal Laminates

Impact responses and damage induced by a drop-weight on GLARE 5 (3/2) fiber–metal laminates (FMLs) with various lay-up configurations were studied experimentally. The effect of specimen geometry wa...
Life stage and sex specificity in relationships between the built and socioeconomic environments and physical activity

Background In the largely cross-sectional literature, built environment characteristics such as walkability and recreation centres are variably related to physical activity. Subgroup-specific effects could help explain inconsistent findings, yet few studies have compared built environment associations by key characteristics such as sex or life stage. Methods Using data from the National Longitudinal Study of Adolescent Health (wave I 1994–5, wave III 2001–2; n=12 701) and a linked geographic information system, cross-sectional relationships between moderate to vigorous physical activity (MVPA) bouts and built and socioeconomic environment measures were estimated. Negative binomial generalised estimating equation regression modelled MVPA as a function of log-transformed environment measures, controlling for individual sociodemographics and testing for interactions with sex and life stage (waves I and III, when respondents were adolescents and young adults, respectively). Results Higher landscape diversity (coefficient 0.040; 95% CI 0.019 to 0.062) and lower crime (coefficient −0.047; 95% CI −0.071 to −0.022) were related to greater weekly MVPA regardless of sex or life stage. Higher street connectivity was marginally related to lower MVPA (coefficient −0.176; 95% CI −0.357 to 0.005) in females but not males. Pay facilities and public facilities per 10 000 population and median household income were unrelated to MVPA. Conclusions Similar relationships between higher MVPA and higher landscape diversity and lower crime rate across sex and life stage suggest that application of these environment features may benefit broad populations. Sex-specific associations for street connectivity may partly account for the variation in findings across studies and have implications for targeting physical activity promotion strategies.
Reduced evolutionary rates in HIV-1 reveal extensive latency periods among replicating lineages

HIV-1 can persist for the duration of a patient's life due in part to its ability to hide from the immune system, and from antiretroviral drugs, in long-lived latent reservoirs. Latent forms of HIV-1 may also be disproportionally involved in transmission. Thus, it is important to detect and quantify latency in the HIV-1 life cycle. We developed a novel molecular clock–based phylogenetic tool to investigate the prevalence of HIV-1 lineages that have experienced latency. The method removes alternative sources that may affect evolutionary rates, such as hypermutation, recombination, and selection, to reveal the contribution of generation-time effects caused by latency. Our method was able to recover latent lineages with high specificity and sensitivity, and low false discovery rates, even on relatively short branches on simulated phylogenies. Applying the tool to HIV-1 sequences from 26 patients, we show that the majority of phylogenetic lineages have been affected by generation-time effects in every patient type, whether untreated, elite controller, or under effective or failing treatment. Furthermore, we discovered extensive effects of latency in sequence data (gag, pol, and env) from reservoirs as well as in the replicating plasma population. To better understand our phylogenetic findings, we developed a dynamic model of virus-host interactions to investigate the proportion of lineages in the actively replicating population that have ever been latent. Assuming neutral evolution, our dynamic modeling showed that under most parameter conditions, it is possible for a few activated latent viruses to propagate so that in time, most HIV-1 lineages will have been latent at some time in their past. These results suggest that cycling in and out of latency plays a major role in the evolution of HIV-1. Thus, no aspect of HIV-1 evolution can be fully understood without considering latency - including treatment, drug resistance, immune evasion, transmission, and pathogenesis.
The cohesive law for the particle/matrix interfaces in high explosives

Abstract The debonding of particle/matrix interfaces has an important effect on the macroscopic behavior of composite materials. There are extensive analytical and numerical studies on interface debonding in composite materials based on cohesive zone models which assume a phenomenological relation between the normal (and shear) traction(s) and opening (and sliding) displacement(s) across the particle/matrix interface. However, there are little or no experiments to determine the cohesive law for particle/matrix interfaces in composite materials. In this paper, we develop a method to determine the cohesive law for particle/matrix interfaces in the high explosive PBX 9501. We use the digital image correlation technique to obtain the stress and displacement around a macroscopic crack tip in the modified compact tension experiment of PBX 9501. We use the extended Mori–Tanaka method (which accounts for the effect of interface debonding) and the equivalence of cohesive energy on the macroscale and microscale to link the macroscale compact tension experiment to the microscale cohesive law for particle/matrix interfaces. Such an approach enables us to quantitatively determine key parameters in the microscale cohesive law, namely the linear modulus, cohesive strength, and softening modulus of particle/matrix interfaces in the high explosive PBX 9501. The present study shows that Ferrante et al.'s [1982 Universal binding energy relations in metallic adhesion. In: J.M. Georges (Ed.), Microscopic Aspects of Adhesion and Lubrication, Elsevier, Amsterdam, pp. 19–30.] cohesive law, which is established primarily for bimetallic interfaces, is not suitable to the high explosive PBX 9501.