cssi/SciSciGPT-SciSciNet huggingface dataset:
Patient handling and musculoskeletal disorders among hospital workers: Analysis of 7 years of institutional workers' compensation claims data

Objectives Musculoskeletal disorders (MSDs) are the most common occupational injuries and illnesses among hospital workers in the United States. To date, there is little in the literature examining the principal effect of patient handling on MSDs. The primary objective of this study was to investigate and confirm the principal effect of patient handling on hospital worker MSDs. Methods Workers' Compensation (WC) claims related to MSDs filed during 2003–2009 by employees in a large US healthcare system were classified using ICD-9. Patient handling, demographic, work, and injury characteristics were obtained. Two multivariable Poisson regression models were compared to evaluate association between risk factors and MSDs. One model contained all risk factors, excluding patient handling; the other model included patient handling. Results Among 3,452 claims from 24,824 FTEs, 76% were MSDs. About half of the MSDs involved patient handling. In the regression model without patient handling, EMS workers, women, 50–59 years of age, union members, evening shift workers, and fulltime workers showed associations with MSDs. However, all the observed associations disappeared when patient handling was included in the second regression model; patient handling was the only factor showing an association with MSDs, although the effect was not strong (RR = 1.2, 95% CI = 1.2–1.3). Conclusions All the observed associations of risk factors disappeared and were further away from patient handling on the causal pathway to MSDs. Patient handling involves numerous work elements and dynamic physical activities. Understanding the work elements of patient handling and conducting interventions based on specific patient handling tasks can substantially reduce MSDs among hospital workers. Am. J. Ind. Med. 55:683–690, 2012. © 2012 Wiley Periodicals, Inc.
Predicting the Effect of Nonionic Surfactants of Interfacial Tensions

The reductions in water–air, oil–air, and water–oil interfacial tensions produced by nonionic surfactants have been successfully predicted using a form of the Langmuir adsorption equation. The reduction in the water-oil interfacial tension produced by a hydrophilic and a lipophilic surfactant acting simultaneously has been successfully predicted using a modified form of the Langmuir equation. The experimental results indicate that all interfacial adsorption sites behave alike, independently of each other. The data also indicate that the lipophilic and hydrophilic surfactants do not interact to reduce interfacial tension more effectively than when used alone. It is suggested that the effect of hydrophilic and lipophilic surfactants on water-oil interfacial tension may serve as an analog for the pharmacological response that would be produced when two drugs which compete for the same sites of action but have different potencies and/or dose response curves are administered together.
Neural Crest Invasion is a Spatially-Ordered Progression Into the Head with Higher Cell Proliferation at the Migratory Front as Revealed by the Photoactivatable Protein, KikGR

Neural crest cell (NCC) invasion is a complex sculpting of individual cells into organized migratory streams that lead to organ development along the vertebrate axis. Key to our understanding of how molecular mechanisms modulate the NCC migratory pattern is information about cell behaviors, yet it has been challenging to selectively mark and analyze migratory NCCs in a living embryo. Here, we apply an innovative in vivo strategy to investigate chick NCC behaviors within the rhombomere 4 (r4) migratory stream by combining photoactivation of KikGR and confocal time-lapse analysis of H2B-mRFP1 transfected NCCs. We find that the spatial order of r4 NCC emergence translates into a distal-to-proximal invasion of the 2nd branchial arch. Lead and trailing NCCs display similar average cell speeds and directionalities. Surprisingly, we find that lead NCCs proliferate along the migratory route and grow to outnumber trailing NCCs by nearly 3 to 1. A simple, cell-based computational model reproduces the r4 NCC migratory pattern and predicts the invasion order can be disrupted by slower, less directional lead cells or by environmental noise. Our results suggest a model in which NCC behaviors maintain a spatially-ordered invasion of the branchial arches with differences in cell proliferation between the migratory front and trailing NCCs.
Bridge retrofit prioritisation for ageing transportation networks subject to seismic hazards

The deteriorating state of highway bridges is traditionally ignored in estimating the seismic reliability of transportation networks. In this study, the present day seismic reliability of ageing bridges in highway networks is evaluated through a time-dependent seismic fragility analysis of typical bridge classes. An efficient algorithm based on finite-state Markov Chain Monte Carlo simulations is also presented to assess the reliability of large ageing highway bridge networks without the need to simplify the network topology. The criticality of ageing bridges is then assessed through different proposed ranking strategies to arrive at an optimised seismic retrofit prioritisation. A case study on an existing bridge network with 515 bridges in the state of South Carolina, USA reveals striking differences between results of the proposed ranking strategies and those from state-of-the-practice methods. Such differences emphasise the significance of accounting for network-level importance in seismic retrofit pro...
Exploratory brand switching: An empirical examination of its determinants

Abstract Exploratory brand switching is switching which arises due to some intrinsic desire for change or variety and which cannot be attributed to dissatisfaction with a previous or existing alternative. Four factors which are likely to influence such switching were examined using consumer self-reports and an experimental design methodology. The factors were Optimum Stimulation Level (OSL, an individual difference variable), brand awareness, monetary deal, and product class. Both homemaker and student samples were used. Results show that brand awareness has a fairly large impact on exploratory switching. Monetary deal has a consistently significant, though much smaller, effect. The influence of OSL is small and erratic. The results vary over product classes, but the relative influence of the factors appears to be generalizable to non-food household items such as cleaning products, paper products, and personal care items. Implications for marketers are outlined.
Third Place—Resident Clinical Science Award 1998: Effects of Cis-Platinum Chemotherapy on Otoacoustic Emissions: The Development of an Objective Screening Protocol

Abstract To develop an objective, fast, and simply performed screening protocol for cis-platinum (CP) ototoxicity, we compared the efficacy of screening with distortion-product otoacoustic emissions (DPOAEs) with the outcome of both conventional and ultra-high-frequency (UHF) audiometry. Baseline audiometric and DPOAE testing was performed in 66 patients, 33 of whom met criteria for inclusion in the final database. Comparisons were made between baseline measurements and those recorded before subsequent CP infusions. Outcomes were analyzed clinically and with paired repeated-measures analysis of variance. Results indicated that DPOAEs and UHF were better measures than conventional audiometry. Further, DPOAEs may be better suited for screening older patients receiving CP chemotherapy because DPOAEs are as sensitive as UHF and are present in a greater number of these patients. Screening with DPOAEs may be enhanced by testing only in the 3- to 5.2-kHz range, thus decreasing testing time. Higher time averages to increase the signal-to-noise ratio and use of this narrower bandwidth might also allow for accurate bedside testing. (Otolaryngol Head Neck Surg 1999;121:693-701.)
How the messenger got its tail: addition of poly(A) in the nucleus

Most mRNAs end in a poly(A) tail, the addition of which is catalysed by a poly(A) polymerase in conjunction with a distinct factor that provides specificity for mRNAs. The reaction is dynamic, involving separable initiation, elongation and termination phases. A companion article in next month's TIBS will review the regulation of poly(A) addition and removal during early animal development.
The current status of tardive dystonia

Tardive dystonia (TDt), a persistent dystonia associated with exposure to neuroleptic drugs, is an uncommon disorder. It differs from tardive dyskinesia (TDk) in epidemiology, clinical features, risk factors, pathophysiology, course, prognosis, and treatment outcome. TDt seems to develop faster and is more painful, distressing, and disabling than tardive dyskinesia. In this article, evidence is reviewed on the face, descriptive, construct, and predictive validity of this iatrogenic complication of antipsychotic drugs. It is suggested that TDt should not be lumped together with TDk. It deserves a separate nosological status as an independent diagnostic category. The subclassification of TDt into various subtypes based on coexistence of other movement disorders is suggested.
Binge Drinking Among College Athletes and Non-Athletes

Concerns about incidence, forms, and consequences of alcohol use among college students lack examinations of the lifestyles and predictors of college student athletes. This article, using a sample of student-athletes and non-athletes from four Southern universities, identifies the lifestyle predictors for each population, identifying patterns and sets of predictors of binge drinking behavior. Findings indicate that for both samples, binge drinking behavior is explained by sex, drinking in bars, number of male friends who drink, and cigarette smoking. Student-athletes' binge drinking is explained further by residing on campus. Non-athlete binge drinking is related to race and amount of study time per week. Implications for these findings are also discussed.
The impact of watching television on evening melatonin levels

Self-luminous electronic devices emit optical radiation at short wavelengths, close to the peak sensitivity of melatonin suppression. The present paper investigated if light from a 178-cm (70 in.) television suppressed melatonin. Results showed that light from televisions does not impact melatonin levels in the evening.
The Effects of Ketoconazole on the Pharmacokinetics of Cyclosporine A in Cats

Objective To determine the effects of ketoconazole (KC) on the pharmacokinetics of cyclosporine A (CsA) elimination in cats. Study Design Research study and prospective clinical trial. Animals Five healthy adult cats (pharmacokinetic studies) and 6 client-owned cats with chronic renal failure. Methods Blood CsA concentrations were measured after CsA (4 mg/kg IV) administration with or without concurrent oral KC (10 mg/kg). Subsequently, a combined CsA-KC immunosuppressive regimen was used in cats after kidney transplantation. Blood CsA concentrations were measured using high performance liquid chromatography. CsA elimination was analyzed using a computerized pharmacokinetics program. Results KC increased blood CsA concentrations 1.8-fold and 2.2-fold at 12 and 24 hours after CsA administration. KC significantly decreased the mean systemic CsA clearance from 2.73 mL/min/kg to 1.22 mL/min/kg resulting in an increase in the terminal phase half-life from 10.7 to 22.2 hours. The volume of distribution of steady-state of CsA was unaffected by KC. In a series of clinical feline kidney transplant patients, a once-a-day CsA-KC regimen was able to be used in most of the cats and was effective for prevention of allograft rejection in all of these cats. Conclusion and Clinical Relevance KC is an effective adjunct treatment for immunosuppression in feline kidney transplant patients. KC suppresses CsA elimination, which reduces the need for CsA and allows once daily administration of CsA.
Ocean science: Gulf of Mexico aftermath

Massive amounts of natural gas catastrophically released into the Gulf of Mexico last year are missing. Two investigations suggest that a bloom of tiny specialized bacteria is responsible for this heavy-duty scrubbing job.
Imaging modalities in pediatric oncology.

The incidence of childhood malignancy has remained relatively stable over the last 30 years. Fortunately, survival rates have improved. 1 Diagnostic imaging plays a central role in the evaluation of malignancy in children. This article reviews the roles of specific imaging modalities in the diagnosis and management of noncentral nervous system childhood cancer. Imaging modalities to be discussed include conventional radiography, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine, including positron emission tomography (PET). Emerging imaging techniques will also be discussed. Current literature will be referenced for more in-depth review. RADIOGRAPHY Conventional radiography plays an important role in the evaluation of cancer in children, not only as an initial screening tool, but also in the assessment of tumor response and recurrence. Conventional radiographs are fast, inexpensive, widely available, and often the initial imaging examination performed in a child with cancer. Conventional radiographs are useful in determining the aggressiveness of bone tumors, and they may identify calcifications in the soft tissues in the abdomen or pelvis or detect pathology in the chest and bones. Conventional radiographs, however, only provide a 1-dimensional representation of 3-dimensional structures, have relatively poor soft tissue contrast, and are often less sensitive and specific than more advanced imaging modalities. Although conventional film-screen technology is stillcommon,thedigitalmodalitiesofcomputedradiography (CR) using a cassette-based system and direct radiography (DR) using a flat-panel based system are widely used. These technologies will likelygain further acceptance asa result of improvements in resolution and decreased radiation exposure in conjunction with more wide-spread use of picture archiving and communication systems
The Surgical Treatment of Coronary Insufficiency

CONCLUSIONS 1. The surgical procedures devised for the treatment of coronary arterial insufficiency may be classified according to the objectives they seek to accomplish. 2. Measures which modify only the clinical manifestations of the coronary arterial insufficiency consist of those which destroy the sympathetic pathways mediating pain sensation from the heart by postganglionic resection of the upper dorsal and lower cervical chains, by division of the preganglionic fibers to these same areas, or by paravertebral injections of alcohol. 3. The only available method which modifies the degree of coronary insufficiency by decreasing myocardial demand is destruction of thyroid function by surgical or medical therapy. 4. Coronary insufficiency may be decreased by a variety of procedures which are designed to increase the size of the coronary vascular bed. These are best termed revascularization techniques, and represent the most physiological approach to the problem. They are classified according to their ability to increase the vascularity at a superficial level or throughout all layers of the myocardium. 5. The blood supply to the epicardium, or the layers immediately beneath the epicardium, may be augmented by omentopexy, myopexy, pneumonopexy, the intrapericardial insufflation of irritants, or the implantation of the bleeding end of the mobilized left internal mammary artery into the left ventricular wall. The intrapericardial instillation of a powdered silicate appears to be the most promising of the surface revascularization procedures. 6. The term total revascularization is applied to the techniques which create an anastomsis between the aorta and the coronary sinus either through a vascular graft (Beck II) or directly (Kralik modification) thus establishing a retrograde flow of arterial blood to the myocardial capillary bed by way of the venous channels. Such retrograde flow is transient but great augmentation of the adequacy of the intercoronary collateral system is produced and remains. Simple ligation of the coronary sinus also may be considered as a total revascularization procedure although a lesser degree of intercoronary overdevelopment is obtained by this procedure. 7. The selection of patients for the revascularization procedures is based upon those manifestations of the disease which indicate an ominous prognosis or seriously interfere with the ability of the patient to meet the requirements of ordinary living. 8. Resection of a ventricular aneurysm represents a promising surgical development in the management of a relatively recalcitrant and untoward cardiac complication which nearly always is the result of occlusive coronary arterial disease. The first historically successful case is herein presented. 9. The development of a seemingly satisfactory and rather safe surgical treatment for complete or varying heart block is detailed with presentation of the first apparently successful human operation.
A systems biology approach to understanding the regulation of lignin biosynthesis

Lignin is a complex phenolic structural component of the secondary cell walls of all vascular plants. It is an irreversible end point of a major metabolic pathway in plant secondary metabolism. Lignin is fundamental to the adaptation of plants to land, the evolution of vascular transport and the resistance of plants to pests and pathogens. Lignin is a major barrier to the utilization of biomass for energy, for papermaking, and for forage digestibility due to the interaction of lignin with cellulosics in the plant cell secondary wall. The past research on lignin biosynthesis is substantial, creating one of a few opportunities in higher plants to integrate genomics, proteomics, biochemistry, chemistry and modeling to develop a comprehensive understanding of biosynthesis and structure of a major component of morphology and adaptation. We are conducting a systems biology study on regulation of lignin biosynthesis in wood formation. We seek to build models to quantitatively illustrate how the entire pathway is organized and regulated and to reveal regulatory and metabolic flux control mechanisms, leading to lignin quantity and structures. We use the model woody plant, Populus trichocarpa (Nisqually-1), and the systems approach including advanced quantitative methods of genomics, proteomics, metabolomics, biochemistry and structural chemistry, to provide a comprehensive analysis of the regulation of lignin biosynthesis. A perturbation strategy is used to systematically knock down the expression of all pathway and regulatory genes known to be involved in lignin biosynthesis during wood formation, and the effects on lignin biosynthesis (gene transcripts, proteins, metabolites, quantity and structures) analyzed using advanced genomic methods available. This information forms the foundation of statistics-based mechanistic modeling and lignin quantity/structural predictions for a quantitative model of lignin biosynthesis. Details of systems data generation, data analyses and model development will be presented. Substantial data have been generated for gene-specific (amiRNA & RNAi) transgenic P. trichocarpa, enzyme kinetics, protein regulation and numerical modeling, and stable-isotope-dilution based absolute quantitation of proteins and of metabolites. These results will be discussed. Our long term goal is a predictive model of lignin biosynthesis and quantity/structure for greater understanding of the plant response to environmental stress and for more precise strategies to improve plant productivity and the production of energy, biomaterials and food.
An algorithm for determining minimal normal forms of an incomplete truth function

In certain applications of truth-function logic it is of interest to consider the minimization problem in a more general form.1 So-called ?algebraic? procedures for determining the irredundant forms of a truth function fall into two categories depending on whether the method requires preliminary expansion of a formula into developed normal form or not. The methods of McCluskey2 and Petrick,3 for example, require canonical expansion of a formula; whereas the table of ratio functions by Gazale4 and a method developed by the author5 determine irredundant forms solely from the list of prime implicants themselves. The latter (referred to hereafter as the ?method of iterated consensus?) arrives at minimal forms by an iterative scheme where the rule of consensus is applied repeatedly to the prime implicants. The purpose of this paper is to indicate how algebraic methods of the second variety apply to the more general case where the class of simplest normal truth functions to be determined is that of formulas equivalent to a given formula ? under the hypothesis that certain conjunctions of letters of ? are always false.
Elastic properties of the incommensurate phase of akermanite, Ca2MgSi2O7

The crystal structure of akermanite, Ca2Mg-Si2O7, consists of mixed tetrahedral sheets formed by [MgO4] tetrahedra and [Si2O7] groups interleaved along the c axis with Ca2+ ions in eight-fold coordination. Above 358 K, the structure is tetragonal \((P\bar 42_1 {\text{ }}m)\), and below it is incommensurate with modulations parallel to [110] and \([1\bar 10]\). The elastic stiffness moduli, Cij of the incommensurate phase at room temperature were measured from wave velocities in the 20–75 MHz carrier frequency range by the ultrasonic phase comparison method using optically clear synthetic single crystal plates (3×3×2 mm) oriented parallel to (100), (001), (110) and (101) planes. The Cij values (GPa) are: C11 159.40, C33 149.43, C44 30.26, C66 58.10, C12 76.58 and C13 57.80. In (010) and (001) planes, the compressional modulus, ρV2(L) from the longitudinal wave, L is considerably larger than the shear moduli, ρV2(T1, T2) both from the in-plane and perpendicular-to-plane shear waves, T1 and T2. The relatively small values of the shear moduli indicate the ease of tetrahedral rotations in response to in-plane and perpendicular-to-plane shears and may provide preconditions for structural changes involving shear-type atomic movements.
A guide to characterizing heat release rate measurement uncertainty for full-scale fire tests†

Accurate heat release rate measurements provide essential information to defining the fire safety characteristics of products. The size, complexity, and cost of full-scale fire tests make achieving accurate and quantitative results a serious challenge. A detailed uncertainty analysis of a large-scale heat release rate measurement facility is presented as a guide to the process of estimating the uncertainty of similar facilities. Quantitative heat release rate measurements of full-scale fires up to 2.7 MW were conducted using the principle of oxygen consumption calorimetry. Uncertainty estimates were also computed for the heat input measurements from a well-controlled natural gas burner. The measurements of heat input and heat release rate were performed independently, and the discrepancy between the two was well within the uncertainty limits. The propagation of uncertainty was performed at the level of voltage and temperature measurements, which avoided using mutually dependent measurement parameters. Reasons for the significant contribution to the combined uncertainty from the oxygen concentration and exhaust flow measurements are demonstrated. Also presented is a first-order effort to account for the uncertainty due to factors in full-scale fire tests such as operator error and environmental influences that are not modeled by the heat release rate equation. Published in 2008 by John Wiley & Sons, Ltd.
Pesticides in Urban Streams and Prespawn Mortality of Pacific Coho Salmon

The listing of several runs of Pacific salmon as threatened or endangered and associated federal, state, and local efforts to restore/enhance salmon habitat in the Pacific Northwest make it imperative that the factors associated with these population declines are understood. Prespawn mortality (PSM) has been documented in coho salmon (Oncorhynchus kisutch) within urban streams in western Washington since the late 1990s and is characterized by a suite of neurological and respiratory symptoms with mortality occurring shortly thereafter. Mortality rates in returning adults have ranged between 17 and 100 %. The cause of PSM is not known, but the presence of pesticide residues within urban streams led to a hypothesis that PSM in coho salmon and pesticides in urban streams were linked. We exposed pairs of “green” (unripe) prespawn male and female coho salmon to a pesticide mixture (“cocktail”) reported in urban streams in western Washington State, USA. Longevity, ripening in female salmon, and brain acetylcholinesterase were not significantly affected by continuous exposure to the maximum reported concentrations of the pesticides. Fertilization, hatching success, and growth of fry were also not affected when green adults were exposed to these concentrations for 96 h. The absence of effects suggests it is unlikely that pesticides within stormwater are singularly responsible for PSM in coho salmon or that they impair the reproductive capability of exposed adults.
Sobolev estimates for the complex green operator on a class of weakly pseudoconvex boundaries

On the boundary of a smooth bounded convex domain in Cn (more generally, a domain that admits a defining funtion that is plurisubharmonic on the boundary), the canonicl (narm-minimizing) solution operator of the -equation, the inverse of □b (the complex Gereen Operator) and the Szego projection are continuous is Sobolev norms.
Hydrazides of N-blocked amino acids as sole substrates with unique difunctional behavior under papain catalysis

Abstract Hydrazides of five N -acylamino acids have been used alone as substrates for papain catalysis to yield N 1 , N 2 -diacylhydrazines. With the exception of N -(benzyloxycarbonyl)(Z)- d -alanine hydrazide, they were very effective as both acylating agents of the enzyme and nucleophiles in attacking the enzyme-substrate intermediate. Although Z - d -alanine hydrazide was a minimal acylating agent, it was a satisfactory nucleophile. The most favorable reaction involved Z- l -alanine hydrazide in producing N 1 , N 2 -bis(Z- l -alanyl)hydrazine. When Z- dl -alanine hydrazide was the substrate, this same chiral diacylhydrazine was formed along with meso N 1 -(Z- d -alanyl)- N 2 -(Z- l -alanyl)hydrazine. For the acylation step, the enzyme displayed powerful, essentially stereospecific, bias toward the l enantiomer. Once the thioester intermediate was formed, little preference was detected for attack by the enantiomers as nucleophiles. The most direct procedure for synthesis of substrates was conversion of Z-amino acids to their esters by means of dry HCl in an absolute alcohol. Treatment with hydrazine produced the hydrazides in excellent yield.
Functional integration of human neural precursor cells in mouse cortex

This study investigates the electrophysiological properties and functional integration of different phenotypes of transplanted human neural precursor cells (hNPCs) in immunodeficient NSG mice. Postnatal day 2 mice received unilateral injections of 100,000 GFP+ hNPCs into the right parietal cortex. Eight weeks after transplantation, 1.21% of transplanted hNPCs survived. In these hNPCs, parvalbumin (PV)-, calretinin (CR)-, somatostatin (SS)-positive inhibitory interneurons and excitatory pyramidal neurons were confirmed electrophysiologically and histologically. All GFP+ hNPCs were immunoreactive with anti-human specific nuclear protein. The proportions of PV-, CR-, and SS-positive cells among GFP+ cells were 35.5%, 15.7%, and 17.1%, respectively; around 15% of GFP+ cells were identified as pyramidal neurons. Those electrophysiologically and histological identified GFP+ hNPCs were shown to fire action potentials with the appropriate firing patterns for different classes of neurons and to display spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs). The amplitude, frequency and kinetic properties of sEPSCs and sIPSCs in different types of hNPCs were comparable to host cells of the same type. In conclusion, GFP+ hNPCs produce neurons that are competent to integrate functionally into host neocortical neuronal networks. This provides promising data on the potential for hNPCs to serve as therapeutic agents in neurological diseases with abnormal neuronal circuitry such as epilepsy.
A Model for Relating Advertising Media Exposures to Purchase Incidence Behavior Patterns

A stochastic model is proposed to study the effect of advertising on consumer purchase dynamics by specifically relating the distribution of exposures, from a brand's media schedule, to brand purchase incidence behavior patterns over time. The approach is based on underlying individual consumer behavior assumptions that reflect the dynamics of exposures to advertising and brand purchase behavior, conditional on the level of advertising exposure received. Moreover, a population-based model is derived by aggregating over individual consumers who may be heterogeneous with respect to exposure probability, purchase rate, and sensitivity to advertising. The approach can be implemented with experimentally-based data and estimation procedures that seek to isolate the effect of advertising and also permit the evaluation of advertising influences on purchase behavior patterns. For the purpose of model implementation, parameter estimation procedures are outlined and applied to empirically evaluate three alternative model versions that reflect different advertising exposure behavior assumptions. Both the goodness of fit results presented and prior empirical experience, in connection with past applications to TV media schedule analysis, lend to the model's validity. The paper concludes with an appraisal of the potential strengths and limitations of the proposed model as a tool for advertising media analysis and planning in practice.
Observation of strain-induced splitting of degenerate valence bands using angle-resolved photoemission spectroscopy.

We report the observation of strain-induced splitting of degenerate valence bands at the Γ point in coherently strained Ge(100) layers using angle-resolved photoemission spectroscopy. Strain was supplied via pseudomorphic epitaxial growth of Ge films on well-ordered InP(100) substrates: the inherent lattice mismatch between the two semiconductors resulted in a 3.9% tensile biaxial strain in the Ge epilayers. A surfactant layer was employed to increase the critical layer thickness and film quality so that measurements could be made on high-quality, fully strained films
Field test measures amount and type of iron in spent acids

The amount and type of dissolved iron present in spent acidizing fluids is important information for stimulation design. This information can be used to optimize the amount and type of iron control chemicals used in an acidizing treatment. With insufficient iron control, precipitation of iron-containing compounds can occur in the near wellbore area and reduce well injectivitity or productivity. Excessive amounts of iron control chemicals can add a significant unnecessary chemical cost to the treatment. In the literature, the ratio of iron (II) to iron (III) from acidizing treatments ranges from 3:1 up to more than 25:1, with ratios of 3:1 most commonly reported. No details are available about the well type or the analytical methods used in the measurements. Typically only one data point was reported for each well tested. In this work, a field method for iron (II) was selected and extensively tested for interferences present in live and spent acids. The method uses 1,10-phenanthroline to form a colored complex with iron (II) only. Total iron concentrations were measured in the lab by inductively coupled argon plasma emission spectroscopy (ICP). Iron (III) was calculated by difference. Since iron (II) is readily oxidized to iron (III) in the presence of air, measurements of iron (II) were made in the field. Spent acidizing fluids obtained from seawater injection wells, oil production wells (dry wells), and oil production wells (high water cut) were evaluated in carbonate reservoirs in Saudi Arabia. At each well, samples were collected and analyzed over the entire flowback time of the treatment. Results showed a variation in the iron (II)/iron (III) ratio and the total iron concentration depending on the well type. Oil production wells (both dry and wet) produced almost entirely iron (II), with low concentrations (less than 1000 mg/L) of total iron. Water injection wells had total iron concentrations up to 30,000 mg/L. In pickle treatments of seawater injection wells, iron (II) to iron (III) ratios from 0.7:1 to 2.0:1 were observed. In the main acid treatment after the well pickle, iron (II) to iron (III) ratios from 2.7:1 to 8.7:1 were measured. These results were calculated based on the amount of iron (II) and iron (III) produced over the entire flowback time of each well. The results of the measurements were used to make significant cost reductions in similar acid treatments. In general, concentrations of iron control chemicals were much higher than required. Significant cost savings were made in the acid stimulation of seawater injection wells. The following new results were obtained: 1. A field method was tested for interferences and adapted for measurement of iron (II) and iron (III) in acids and stimulation fluids. 2. Iron (III) was only observed in significant amounts in seawater injection wells. 3. The ratio of iron (II) to iron (III) observed in water injection wells was much lower (more Fe (III)) than previously reported. 4. Iron (III) reducing agents are not required in the oil production wells examined in this work.
Bacterial characteristics important to rhizosphere competence

Inoculation of bacteria onto seeds and roots has attracted growing interest for the purpose of biological control, nitrogen fixation, and plant growth promotion. A major impediment to fully exploiting the potential of microorganisms in these areas has been a lack of knowledge about factors determining rhizosphere competence. Recently, studies have been conducted which evaluate the contribution of specific characteristics to the root-colonizing ability of individual bacteria. The purpose of the present study was to compare bacteria isolated from roots and from soil with respect to several characteristics that have been suggested as important to successful root colonization.
Coherence as an explanation for theory of mind task failure in autism

O’Loughlin and Thagard (2000) present a specific computational implementation of the idea that the problems encountered by a child with autism in classic False Belief tasks derive from a failure to maintain coherence among multiple propositions. They argue that this failure can be explained as a structural feature of a connectionist network attempting to maintain coherence. The current paper criticizes this implementation because it falsely predicts that the same children will have a parallel problem with the False Photographs task. The fact that the content of representations makes a difference while the structure remains constant casts doubt upon their claim.
Gentamicin-resistantPseudomonas aeruginosa: Concepts regarding their evolution and attenuated virulence.

Pseudomonas aeruginosa, a free-living bacterial species, is a major nosocomial pathogen, especially of compromised patients within medical facilities. Numerous factors contribute to the ecological selection of this bacterial species within the hospital environment, among which the expression of newly acquired or quiescent enzymatic capability seems par-amount. The emergence of pathogenic strains ofP. aeruginosa appears to be gradual, embodying a transition of strains from their natural aquatic environment, to establishing inanimate (hospital) and animate (human) reservoirs. In this stepwise transition, subsets ofP. aeruginosa may evolve which express a survival trait, for example, gentamicin resistance, but concomitantly suffer a loss of invasive potential. In this study,P. aeruginosa strains from natural [22], hospital [11], and stool [17] sources were evaluated for their physiological and exoenzymatic activity and compared with gentamicin-resistantP. aeruginosa (GRPA) strains [49] of clinical origin. As a whole, environmental and hospital isolates showed reduced enzymatic potential, for example, frequency of production of elastase, lipase, deoxyribonuclease, and pyocyanin production. Human fecal isolates most closely resembled the prototype of human invasiveP. aeruginosa in their gentamicin susceptibility (95%) and increased frequencies of exoenzymes, including elastase production. On the other hand, GRPA were frequently apyocyanogenic (9/49), lacked extracellular enzymes correlated with pathogenicity, and were rarely isolated from systemic sites. When encountered, these strains appeared to represent colonization of a body site rather than incitants of overt infection. As a “subset” ofP. aeruginosa, gentamicin resistance was seen predominantly among serotype 11 strains, and encountered most frequently from patients with localized urinary tract infections.
An integrated system for microalgal and nursery seed clam culture

A PC-controlled integrated system for the production of algae and culture of northern quahog seed was constructed. The diatom, Chaetoceros muelleri, was cultured in covered 550 l tanks. The harvested alga was the food source for the land-based nursery seed clam system. The nursery clam system consisted of six culture units constructed of clear PVC tubing, a 400 l feed reservoir, a solids separator, and a bead filter (0.03 m3). The culture units were 5 cm in diameter and 76 cm in height. The total system volume was 450 l and the recirculation flow rate was 40 lpm. Components of the computer control system include a laptop computer, a multiport connector, analog to digital converter (ADC) boards, and solid-state relays for each control output. Sampling, harvesting, refilling, and redosing of the algal chambers, seed clam feeding operations, cleaning of the seed bed by increased fluid flow, purging of the separator wastes, and backflushing of the bead filter were all computer controlled. The integrated system was tested using Mercenaria seed clams. The initial shell length of the seed clams were 2.5 (±0.5) mm, and were stocked at a density of 3.0 g whole wet weight cm−2. During 83 days of culture using the system the seed clams were sorted twice and reached an average shell length of 7.9 (±0.8) mm. The percentage of survival percent was determined at different stages of growth during the culture period and ranged from 67.3 to 88.0%.
Classification of forbidden subsequences of length 4

We complete the classification of forbidden subsequences of length 4 by resolving the last open question concerning thesymmetry classesof (1234) and (4123). Our method is to construct specificswitchingoperations onSn(123) which partition its elements intoequivalence classes.This and the fact that the treeT(123) can be embedded nicely inT(1234) andT(4123) lead to the conclusion that |Sn(1234)|= |Sn(4123)| for alln∈N.
Rapid thermal processing of ZnTe:Cu contacted CdTe solar cells

Cadmium telluride (CdTe) is a leading absorber for thin-film solar cells. However, state-of-the art open circuit voltages (V oc ) of CdTe thin film solar cells fall ∼350 mV below the value expected based on the band gap of CdTe. One of the reasons is due to barriers at the back contact. In this paper, we report on the development of a the back contact process for ZnTe:Cu contacted device that employs rapid thermal processing (RTP) to precisely control the activation and distribution of Cu. It is shown that 30 s annealing steps significantly improve fill factor and V oc without compromising the current density. Devices with >14% efficiency and >825 mV V oc are obtained under optimal conditions.
Bifurcations leading to summer Arctic sea ice loss

[1] There is significant interest in whether there could be a bifurcation, sometimes referred to as a “tipping point,” associated with Arctic sea ice loss. A low-order model of Arctic sea ice has recently been proposed and used to argue that a bifurcation associated with summer sea ice loss (the transition from perennial to seasonal ice) is unlikely. Here bifurcations are investigated in a variation of this model that incorporates additional effects, including parameterizations of changes in clouds and heat transport as sea ice is lost. It is shown that bifurcations can separate perennially and seasonally ice-covered states in this model in a robust parameter regime, although smooth loss of summer sea ice is also possible. Hysteresis and jumps associated with bifurcations involving winter sea ice loss are larger than those associated with summer sea ice loss. Finally, in analogy with simulations in global climate models, the low-order model is integrated with time-varying greenhouse gas forcing in both the regime in which summer sea ice is lost via bifurcations and the regime in which it is not. The resulting time series are compared as a preliminary way of investigating ways in which these regimes could be distinguished from each other.
Health-effects related structure-toxicity relationships: a paradigm for the first decade of the new millennium.

Abstract Prediction of the effects of industrial chemicals to humans will be an area of increasing concern in the next century. The role of quantitative structure–activity relationships (QSARs) is to aid in the prediction of effects by determination of the limits of variation in structure that are consistent with the production of a specific toxic effect and define the ways in which alterations in structure influences toxicity. The paradigm followed in the development of QSARs for ecotoxic-endpoints has been successful as a direct result of the availability of in vivo toxicity data in which to build initial QSARs and validate surrogate test systems. However, the lack of quantitative in vivo toxicity data means this paradigm cannot be used in the prediction of human health-effect endpoints. Therefore, a new paradigm, which provides guidance in the use of predictive QSARs for health-effects that serves to circumvent the problems associated with the lack of whole-mammal toxicity data must be established. A scenario is given that provides for the development, standardization, and validation of health-effects related QSARs in the first decade of the 21st century. Due to the structural diversity and sheer number of industrial organic chemicals, assays used to garner health-effects data must be based on quantifiable, rapid, reliable, and inexpensive surrogate endpoints. New ‘biotools’ developed using modern molecular techniques will aid in the circumvention of in vivo health-effects data and provide measurable endpoints, which can be used as surrogates for health-effects endpoints. This has particular application in receptor-mediated toxicity and gene expression. The lack of whole-mammal health-effects data means that the standardization and validation, of these endpoints will be accomplished in novel ways. Databases garnered using modern biotools will allow the derivation of QSARs developed for validated surrogate health-effect endpoints. If QSARs are to be useful in bridging gaps in health-effects data, they must be based on accurate, reproducible data for a robust series of non-congeneric chemicals. The latter applies to both toxicity and descriptor values. Because health-effects are often the result of metabolic activation, if these new QSARs are to be meaningful, validated software for predicting metabolite formation must be incorporated. Lastly, once QSARs and software are developed and validated, they will need to be linked into some type of expert system.
To Slip or Skip, Visualizing Frameshift Mutation Dynamics for Error-prone DNA Polymerases

Abstract Three models describing frameshift mutations are “classical” Streisinger slippage, proposed for repetitive DNA, and “misincorporatation misalignment” and “dNTP-stabilized misalignment,” proposed for non-repetitive DNA. We distinguish between models using pre-steady state fluorescence kinetics to visualize transiently misaligned DNA intermediates and nucleotide incorporation products formed by DNA polymerases adept at making small frameshift mutations in vivo. Human polymerase (pol) μ catalyzes Streisinger slippage exclusively in repetitive DNA, requiring as little as a dinucleotide repeat. Escherichia coli pol IV uses dNTP-stabilized misalignment in identical repetitive DNA sequences, revealing that pol μ and pol IV use different mechanisms in repetitive DNA to achieve the same mutational end point. In non-repeat sequences, pol μ switches to dNTP-stabilized misalignment. pol β generates –1 frameshifts in “long” repeats and base substitutions in “short” repeats. Thus, two polymerases can use two different frameshift mechanisms on identical sequences, whereas one polymerase can alternate between frameshift mechanisms to process different sequences.
A computational study of gas-phase and surface reactions in deposition and etching of GaAs and AlAs in the presence of HCl

Abstract Gas-phase and surface reaction mechanisms underlying MOCVD of AlAs and GaAs in the presence of HCl are studied using quantum chemistry. Density functional theory and conventional transition state theory are used to determine kinetic constants of gas-phase reactions following the dissociation of Al(CH3)3 and Ga(CH3)3 and the subsequent reactions with HCl. The developed kinetic schemes are then explored through sensitivity analysis. Adsorption energies of the most abundant gas phase molecules as well as activation energies of key reactions on GaAs and AlAs (1 0 0) surfaces are predicted quantum chemistry computations. The surface is modeled as semiconductor clusters of increasing size. Comparisons of predictions to available experimental data show that a cluster need to reproduce the β2(2×4) surface reconstruction in order to successfully predict the surface reactivity. Surface and gas phase kinetic schemes are developed on the basis of the calculations as well as published data. These reaction schemes are linked with a two-dimensional computational fluid dynamic model to simulate experimental growth rates measured in different reactors. The simulations suggest that the AlAs gas phase and surface chemistry differ from that of GaAs. In particular, the mechanism for desorption of CH3 and Cl from an AlAs surface is different from that active for a GaAs surface.
Further studies of the transkull transmission of an intense focused ultrasonic beam: Lesion production at 500 kHz

Abstract Focal lesions in lucite blocks and live brain tissue produced by an intense focused 500 kHz ultrasonic beam which had first been transmitted through an excised adult human skull section (formalin fixed) are described. The incident acoustic intensifies ranged from about 880 to 1200 W/cm 2 with exposure durations of 5–6 sec. The character of such lesions suggests that essential focal beam dimensions and temporal coherence of the sound wave were preserved with minimal distortion after transmission through this particular skull section (7–8 mm thickness over the region of sound transmission), which has been determined to exhibit sound intensity losses of about 16 dB at 500 kHz. These appears to be little heating of the skull section during irradiation at this incident intensity.