cssi/SciSciGPT-SciSciNet huggingface dataset:
Influence of nonenzymatic glycation on biomechanical properties of cortical bone

In this study, the influence of nonenzymatic glycation (NEG) on the mechanical properties of bone and bone collagen were investigated. Bovine cortical bone specimens were incubated in ribose to cause collagen cross-links in vitro, and nondestructive mechanical testing was used to determine tensile and compressive elastic modulus as a function of incubation time. Mechanical properties associated with yield, postyield, and final fracture of bone were determined at the end of the incubation period. The stiffness of the collagen network was measured using stress relaxation tests of demineralized bone cylinders extracted periodically throughout the incubation period. It was found that accumulation of nonenzymatic glycation end-products in cortical bone caused stiffening of the type I collagen network in bone (r2 = 0.92; p < 0.001) but did not significantly affect the overall stiffness of the mineralized bone (p = 0.98). The ribosylated group had significantly more NEG products and higher yield stress and strain than the control group (p < 0.05). Postyield properties including postyield strain and strain energy were lower in the ribosylated group but were not significantly different from the control group (p = 0.24). Compared with the control group, the ribosylated group was characterized by significantly higher secant modulus and lower damage fraction (p < 0.05). Taken together, the results of this study suggest that collagen in bone is susceptible to the same NEG-mediated changes as collagen in other connective tissues and that an increased stiffness of the collagen network in bone due to NEG may explain some of the age-related increase in skeletal fragility and fracture risk.
Bandwidth-Tunable Add-Drop Filters Based on MEMS-Actuated Single-Crystalline Silicon Microtoroidal Resonators

A bandwidth-tunable filter has been demonstrated by MEMS-actuated single-crystalline silicon microtoroidal resonator. Bandwidth is tuned from 2.8 to 78.4 GHz by voltage control. A 21.8 dB extinction ratio is attained as a dynamic add-drop filter.
Intrahepatic expression of HBcAg and delta antigen in anti-HBe positive HBsAg carriers with acute exacerbation or chronic active liver disease

Intrahepatic expression of HBcAg and hepatitis delta antigen (HDAg) was studied in 43 patients with acute exacerbation AE and 37 with chronic active liver disease CALD, in order to evaluate the role of hepatitis B virus (HBV) replication and hepatitis delta virus (HDV) superinfection in development of AE or CALD in anti-HBe positive HBsAg carriers in Taiwan, and the results were compared with 37 patients with only minor hepatitic activity. Only 8.1% of patients with minor hepatitic activity were HBcAg positive, and none were HDAg positive. In contrast, 41.8% and 32.6% of patients with AE were positive for HBcAg and HDAg, respectively, and the other 25.6% were negative for both. The clinical features of AE showed no difference in relation to HBcAg and HDAg activity in the liver except that patients without HBcAg and HDAg were predominantly older adults. These patients might be supposed to have non-A, non-B hepatitis (NANB) virus superinfection, as many reports have shown a predominance of older patients in acute NANB hepatitis. Of the patients with CALD, 40.5% were HBcAg positive, 27.0% were HDAg positive, and 32.5% were positive for neither. Histological features of CALD were identified in 83.3% and 100% of patients with HBcAg and HDAg activity, respectively, but only in 26.1% of those without HBcAg and HDAg. The etiology of CALD in the latter group remains unclear. Furthermore, some of the anti-delta seropositive patients with AE or CALD expressed HBcAg rather than HDAg in the liver.(ABSTRACT TRUNCATED AT 250 WORDS)
Monte Carlo Information-Reuse Approach to Aircraft Conceptual Design Optimization Under Uncertainty

This paper develops a multi-information source formulation for aerospace design under uncertainty problems. As a specific demonstration of the approach, it presents the optimization under uncertainty of an advanced subsonic transport aircraft developed to meet the NASA N+3 goals and shows how the multi-information source approach enables practical turnaround time for this conceptual aircraft optimization under uncertainty problem. In the conceptual design phase, there are often uncertainties about future developments of the underlying technologies. An aircraft design that is robust to uncertainty is more likely to meet performance requirements as the technologies mature in the intermediate and detailed design phases, reducing the need for expensive redesigns. In the particular example selected here to present the new approach, the multi-information source approach uses an information-reuse estimator that takes advantage of the correlation of the aircraft model in the design space to reduce the number of m...
A hydrodynamic approach to particle target efficiency in the presence of diffusiophoresis

Abstract An alternate approach to estimating the diffusiophoretic target efficiency of small particles by spherical collectors is presented. The vapor diffusion flux affecting the particle motion is incorporated into the fluid velocity field using different source terms for viscous and potential flow about the sphere. The calculated target efficiencies depend on the respective source terms, in addition to the Stokes number, collector Reynolds number, and interception parameter. The calculated diffusiophoretic target efficiency decreases for an evaporating drop and increases for a condensing drop. These effects become more pronounced as the source term becomes more positive or more negative. In the latter case, the target efficiency can exceed unity for small Stokes number and strong diffusion fluxes toward the collector surface.
Naval weaponry and the law of the sea

Abstract Major naval weapons and weapons systems are examined as they relate to naval strategy and the law of the sea. Although there are some legal limitations on the development and use of nuclear and other mass destruction weapons on the seabed, and in nuclear free zones such as Latin America, and on naval weaponry in Antarctica, the use of naval weapons systems is largely unrestricted by international law and the law of the sea. Weapons systems from mines to large submarines and carriers are related to areas, to categories of states, and to the main sub‐fields of international relations. The conclusion to be drawn is that a third Hague Conference on the laws of war should be called and arms control and disarmament issues in naval weaponry should be addressed urgently. Detailed data on naval weapons, missile systems, and maritime zones are presented in three appendixes. Glossary of Abbreviations for Naval Weaponry immediately precedes the appendices.
Characterization by CO/FTIR spectroscopy of palladium supported on NaY zeolites

Abstract Oxidized and reduced Pd/NaY samples were characterized by CO/FTIR spectroscopy. After calcination at 500°C, most Pd2+ ions are inaccessible to CO; those which are, have various oxidation numbers. After mild reduction at 350°C and admission of CO, FTIR spectra with sharp bands appear, suggesting that most Pd atoms are present in similar Pd clusters. A band at 2120 cm−1 indicates a strong electron-deficient character. Reduction at 450°C, followed by adsorption of CO produces IR spectra of little structure, similar to CO on Pd supported on amorphous oxides, lacking the 2120 cm−1 band. After extensive purging in Ar for 4 h most CO is removed, but residual terminal and multiply bonded CO remains detectable, the latter still distinguishing gently reduced (1829 cm−1) and severely reduced (1904 cm−1) samples. It is concluded that the calcination temperature is decisive for the fraction of Pd present in the supercages after gentle reduction, but the reduction temperature determines the microgeometry of the sites adsorbing CO on Pd particles in supercages.
Candesartan cilexetil in combination with low-dose hydrochlorothiazide is effective in severe hypertension

This randomized, double-blind, placebo-controlled multicenter study was designed to evaluate the efficacy, tolerability, and safety of candesartan cilexetil in a diverse population of patients with severe systemic hypertension (diastolic blood pressure > or =110 mm Hg). After a placebo run-in period, patients were given hydrochlorothiazide (HCTZ) 12.5 mg once daily for 1 week. A total of 217 patients with sitting diastolic blood pressure >95 mm Hg while receiving HCTZ were then randomized in a 2:1 ratio to receive candesartan cilexetil or placebo once daily for 4 weeks. Candesartan cilexetil was started at 8 mg and titrated to 16 mg if needed for blood pressure control; background HCTZ was continued in both groups. Candesartan cilexetil was significantly more effective than placebo in lowering trough diastolic and systolic blood pressure. The mean change in trough sitting diastolic blood pressure from the end of the HCTZ run-in period to the week 4 endpoint (primary study endpoint) was -9.1 mm Hg with candesartan cilexetil and -3.1 mm Hg with placebo (p = 0.0001). A higher percentage of patients treated with candesartan cilexetil than placebo responded to treatment (53% vs 29%) and achieved diastolic blood pressure <90 mm Hg (32% vs 15%). Subgroup analyses indicated that candesartan cilexetil was especially effective in patients with higher trough diastolic blood pressure at randomization, and it was significantly more effective than placebo in both black and nonblack patients alike as well as in women and men. Candesartan cilexetil was safe and well tolerated, with an adverse-event profile comparable to placebo. These results demonstrate that candesartan cilexetil added to background HCTZ therapy is effective and well tolerated in lowering blood pressure in patients with severe systemic hypertension.
Qualitative models of spreading-center processes, including hydrothermal penetration: reply

Abstract Observations on active geothermal areas suggest that water can penetrate rapidly into hot rock, and this is confirmed by semi-quantitative theory. Upwelling of magma material at an oceanic spreading center places hot rock close to an ample supply of cold water. Clues to the nature of the interaction can be found in the structure of ophiolite suites, and in simple physical induction on the nature of the upwelling. The subsurface dike injection zone seems to be dominated by conductive cooling and to provide a barrier against water penetration as long as it is heated by liquid magma in a chamber below. As soon as the magma has crystallized into a cumulate, water penetration proceeds rapidly to the base of the crust. It is probably stopped by meeting an ultramafic layer of olivine phenocrysts separated from the upwelling melt. The olivine crystals may be oriented by a fluidized-bed process near the spreading axis, forming a thin acoustically anisotropic layer. Below, mantle material depleted by partial melting grades back to primitive composition at depth. The mantle material should remain viscous enough to upwell in a broad zone, and the coupling of distributed upwelling to a thick rigid crust formed close to the spreading axis is responsible for the central valley and block tectonics characteristic of slow-spreading ridges. At fast spreading rates, the larger magma chamber decouples a thinner rigid surface layer and smooth topography results.
Knowledge representation issues in complex decision domains: an example from inherent audit risk assessment

There has been significant discussion in artificial intelligence and expert systems concerning different representation systems for complex domain knowledge. This article discusses the strengths, weaknesses and psychological validity of two common systems, associational or rule- and model-based, and presents a computer model which incorporates both approaches into a hybrid system. The computer model reasons in the complex decision domain of inherent audit risk assessment.
Cell cycle control of morphogenesis in budding yeast

A detailed description of the cytoskeletal rearrangements that orchestrate bud formation is beginning to emerge from studies on yeast morphogenesis. In this review, we focus on recent advances in our understanding of how the timing of these rearrangements is controlled. Dramatic changes in cell polarity that occur in G1 (polarization to the bud site), G2 (depolarization within the bud), and mitosis (repolarization to the mother/bud neck) are triggered by changes in the kinase activity of Cdc28, the universal regulator of cell cycle progression. The hunt for Cdc28 morphogenesis substrates is on.
Metabolism of d-xylose and d-xylonic acid in vivo and in vitro by the guinea pig

Abstract After intraperitoneal injection of a tracer dose of d -xylose-1-14C into guinea pigs, 10.8 ± 2.0% (mean ± one standard deviation) of the radioactivity was recovered as expired 14CO2 in 4 hours and 41.3 ± 3.0% as urinary 14C in 5 hours. Approximately 60% of the urinary 14C exhibited chromatographic properties identical to those of authentic d -xylose; the remainder migrated as a single unidentified compound. After injection of d -xylose-1-14C into nephrectomized guinea pigs, a mean of 28.3% (range 23.0–32.0) of the radioactivity was recovered as 14CO2 in 6 hours. In vitro studies revealed that kidney and liver oxidize d -xylose-1-14C to 14CO2. Liver extract catalyzed the conversion of d -xylose to d -xylonic acid with pyridine nucleotide as a cofactor. Evidence is presented to show that this enzyme activity differs from hepatic glucose dehydrogenase. d -Xylonic acid-1-14C was oxidized to 14CO2 by intact guinea pigs. Slices of kidney and liver, and homogenates of kidney carried out this oxidation in vitro. These observations support the possibility that the oxidation of d -xylose by the guinea pig involves its initial conversion to d -xylonic acid and subsequent decarboxylation.
A CONSERVATIVE ISOPARAMETRIC SPECTRAL ELEMENT METHOD FOR FORCED CONVECTION; APPLICATION TO FULLY DEVELOPED FLOW IN PERIODIC GEOMETRIES

This paper addresses the problem of unsteady, flux-driven, fully developed forced convection in general periodic configurations, in which globed conservation properties are used to uniquely determine the proper form for developed thermal profiles. A numerical implementation of the problem is formulated using the isoparametric spectral element method, a high-order (exponentially convergent) finite-element technique for solution of the unsteady incompressible Navier-Stokes and energy equations. As the problem statement requires global energy balance, special emphasis is placed on proper treatment of the convective terms so as to ensure conservation of thermal energy in the appropriate discrete sense. The technique is applied to several test problems, including steady-periodic flow in grooved channels and steady flow past cylindrical obstructions, to indicate the stability, accuracy, and generality of the formulation.
Use of Two Waterbird Guilds as Evaluation Tools for the Kissimmee River Restoration

Two groups of waterbirds have been chosen to assist in measuring the success of restoration of the traditional channel configuration, hydrologic regimes, and floodplain wetlands of the Kissimmee River : waterfowl (Anseriformes) and waders (Ciconiiformes). Waterfowl are dominant, swimming omnivores that use seeds, foliage, and invertebrates; waders are mainly walking predators that eat fish of various sizes. Both can be censused by well-established air and ground techniques, and both can be used to compare post-restoration with channelized or pre-channelization population data (waterfowl) or bird use of channelized versus restored wetlands (waders). In addition to use of population data, species richness and regularity of occurrence should provide a basis for assessing restoration of biological integrity. Conceptual models of avian habitat use for nesting and feeding demonstrate patterns of segregation that will aid assessments for some species. Other species show high overlap in foods and habitats and will require additional measures of response. To understand these patterns and reasons underlying waterbird use, measurements of habitat type, vegetation structure, and food resources will be essential. Integration of these high trophic, level guilds with evaluations of other system components will ensure an ecosystem perspective. Predicted responses to restoration suggest an increase in species richness and number of individuals of many species.
Leveraging public‐private partnerships to improve community resilience in times of disaster

Purpose – As noted in the Department of Homeland Security's National Response Framework, disasters are inherently local and ultimately the responsibility of the lowest jurisdictional level present within the impacted area. Given these parameters, this paper aims to sharpen the concept of national resilience by recommending a framework which positions community resilience as an integral variable in understanding the ability of impacted areas to effectively manage the consequences of disasters. Conceptualized as a dependent variable, community resilience is influenced by the relationships government (public) agencies develop with private sector partners and the resilience of relevant supply chains and critical infrastructures/key resources which exist in their communities.Design/methodology/approach – The authors augment a topical literature review of academic and practitioner journals by synthesizing existing findings into a holistic framework of community resilience.Findings – This paper argues that inter...
Observation of resonant tunneling in silicon inversion layers.

Measurements of the temperature and carrier-density dependence of the strongly localized conductance of short silicon inversion layers are reported. At the lowest temperatures we observe well-isolated, large conductance peaks whose width and temperature dependence are only consistent with resonant tunneling and are inconsistent with Mott hopping. Several new features are observed which we believe may be the result of Coulomb interactions.
Intravenous basic fibroblast growth factor does not ameliorate brain injury resulting from transient focal ischemia in cats

This study sought to test the hypothesis that intravenous basic fibroblast growth factor (bFGF) inhibits the development of brain injury during transient focal ischemia. Halothane-anesthetized cats (n=39) underwent left middle cerebral artery occlusion for 60 minutes. After the onset of reperfusion, wounds were closed and the cats were allowed to emerge from anesthesia. Experimental cats were treated with intravenous bFGF at a dose of either 2 or 5 microg/kg per hour, beginning 45 minutes after initiation of ischemia and continuing until 24 hours of reperfusion, when neurologic function and infarction volume were evaluated. The cats in the control group received diluent. Three of thirteen cats treated with bFGF 2 microg/kg/hour and six of sixteen cats treated with bFGF 5 microg/kg/hour died during the 24 hour reperfusion period. There was no difference in injury volume or neurologic evaluation score in the control group (n=10; hemisphere injury, 1301+/-306 mm3, mean+/-SE; score 53+/-3), and cats treated with either 2 microg/kg/hour (n=10; hemisphere injury, 1170+/-292 mm3; score 50+/-3) or 5 microg/kg/hour bFGF (n=10; hemisphere injury, 1343+/-374 mm3; score 50+/-2). The data collected do not support the hypothesis that intravenous bFGF is neuroprotective in a cat model of transient focal ischemia.
Chaos due to homoclinic and heteroclinic orbits in two coupled oscillators with nonisochronism

We show that chaotic dynamics occur in a pair of weakly nonlinear coupled active oscillators when nonisochronism, the dependence of oscillation frequencies on amplitudes, is included. The strange attractor in this system develops from a nearby homoclinic orbit, the same mechanism that leads to chaos in coupled active-passive modes. After analytically determining the most likely parameter region for such a homoclinic orbit, we found the neighboring region of chaos predicted by Shilnikov's theorem. These coupled oscillators also exhibit multistability and unexpected three-frequency oscillations.
Discovery and evidence of nitrogen fixation by thermophilic heterotrophs in hot springs

A previously unknown phenomenon, nitrogenase activity at high temperatures by nonphotosynthetic prokaryotes in thermal springs, is reported. This activity was revealed by dark-bottle incubations during cyanobacterial nitrogenase studies in hot springs of Yellowstone National Park. Benthic mat cores from alkaline thermal streams reduced acetylene in the dark from 30° to 60°C. the bacterial activity was distinguished from that of sympatric cyanobacteria by its sensitivity to oxygen (light bottles), heterotrophic response to organic amendments, and distinctive spatial distribution. Field tests for other biotic or abiotic explanations of the activity were negative. Anaerobic enrichment cultures supported the field evidence. Fourteen morphological types of presumptive diazotrophs, including sulfate-reducing and spore-forming rods. have been observed in these cultures.
Simultaneous pole assignment in linear periodic systems by constrained structure feedback

The authors present methods for pole assignment by feedback with constrained structure in linear periodic systems using generalized sampled-data hold functions (GSHF). Constrained structure is taken to mean that the input of each channel is restricted to depend only on the measurements of some specific output channels. The basic idea of GSHF control is to use sample and hold, but to consider the hold function as a design parameter. Four strategies are proposed for closing a control loop using GSHF. The key to the results obtained is that, when GSHF control with constrained structure is applied to a periodic system, a discrete-time time-invariant, decentralized system is obtained for which control design methods are available. >
Metabolic and mitochondrial disorders associated with epilepsy in children with autism spectrum disorder

Autism spectrum disorder (ASD) affects a significant number of individuals in the United States, with the prevalence continuing to grow. A significant proportion of individuals with ASD have comorbid medical conditions such as epilepsy. In fact, treatment-resistant epilepsy appears to have a higher prevalence in children with ASD than in children without ASD, suggesting that current antiepileptic treatments may be suboptimal in controlling seizures in many individuals with ASD. Many individuals with ASD also appear to have underlying metabolic conditions. Metabolic conditions such as mitochondrial disease and dysfunction and abnormalities in cerebral folate metabolism may affect a substantial number of children with ASD, while other metabolic conditions that have been associated with ASD such as disorders of creatine, cholesterol, pyridoxine, biotin, carnitine, γ-aminobutyric acid, purine, pyrimidine, and amino acid metabolism and urea cycle disorders have also been associated with ASD without the prevalence clearly known. Interestingly, all of these metabolic conditions have been associated with epilepsy in children with ASD. The identification and treatment of these disorders could improve the underlying metabolic derangements and potentially improve behavior and seizure frequency and/or severity in these individuals. This paper provides an overview of these metabolic disorders in the context of ASD and discusses their characteristics, diagnostic testing, and treatment with concentration on mitochondrial disorders. To this end, this paper aims to help optimize the diagnosis and treatment of children with ASD and epilepsy. This article is part of a Special Issue entitled "Autism and Epilepsy".
Collagenase in Wound Healing: Effect of Wound Age and Type

Collagenase is believed to be important for cell migration and collagen remodeling during tissue repair and regeneration. We have investigated collagenase concentrations in different types of surgically inflicted wounds in pigs. Collagenase was extracted from tissue homogenates of wounds by heating to 60 degrees C for 6 min in 0.1 M CaCl2. The molecular weight of latent collagenase was about 52 kDa. Activated collagenase produced the characteristic 3/4 fragment of collagen. Collagenase was assayed by the use of radiolabeled telopeptide-free collagen. To detect maximal collagenase activity, extracts were reduced and alkylated to destroy inhibitors, then activated with aminophenylmercuric acetate. Sutured incisions showed peak collagenase content on postoperative day 1 and thereafter steadily declining concentrations. Granulation tissue from non-sutured large defect full-thickness wounds showed high collagenase content on postoperative day 5 and then a sharp decline to day 7 followed by a slowly declining curve to postoperative day 21. Partial-thickness wounds exhibited a different time course, with collagenase increasing to peak concentrations on postoperative days 3-5; however, a large proportion of the detected collagenase was due to the adherent scab. By day 7 collagenase concentrations approached the low concentrations of normal skin when epithelialization was complete and the scab rejected. In general, collagenase shows an early maximum and then declines with postoperative time, with the sharpest decline occurring when epithelialization is complete.
Endoreplication: The advantage to initiating DNA replication without the ORC?

The endocycle is a developmentally specialized cell cycle that lacks M phase and consists of only S and G phases. Endoreplicating cells acquire high ploidies by multiple rounds of replication without cell divisions in order to increase protein synthesis to support growth and development of the organism. Endoreplication occurs in developmentally specialized cell types after they terminally differentiate. These cells include: ovarian nurse cells and follicle cells, most of the larval tissues in flies and the placenta giant trophoblasts and megakaryocytes in mammals. To date, studies of endoreplication have mainly focused on two aspects: Cyclin-dependent kinase (CDK)-mediated controls to license and re-license replication origins in the absence of mitosis, and development or differentiation signaling pathways that mediate the transition from mitotic replication to endoreplication. The replication initiation machinery itself has not been much studied, partly because it has been generally considered to consist of the same set of factors used in mitotic cycle. Recently we reported a loss-of-function analysis of the Drosophila orc1 gene, which revealed that the Origin Recognition Complex (ORC) is dispensable for endoreplication. This finding is surprising and rather provocative as it runs against the accepted dogma and is expected to stimulate discussion and interest in the identification of the molecular mechanisms of the initiation of endoreplication. What follows is a highly speculative view of how endoreplication occurs in the absence of the ORC and what advantage ORC-independent replication brings to the organism.
The emissivity of the diffuse spherical cavity.

Similarities between various cavity emissivity theories have been examined. It is shown here that, for the special case of the (isothermal) diffuse spherical cavity, the closed form emissivity expressions obtainable from the work of Gouffe, DeVos, and Sparrow and Jonsson agree exactly. Further, this result is not limited by the size of the opening in the cavity.
Envisioning an emission diet: Application of travel demand mechanisms to facilitate policy decision making

Emission reduction strategies are gaining attention as planning agencies work towards adherence to air quality conformity standards. Policymakers struggling to reduce greenhouse gases (GHG) must grapple with a growing number of travel demand policies. To consider any of these emerging demand mechanisms as a viable option to meet emission targets, planners and policymakers need tools to better understand the implications of such policies on travel behavior. In this paper we present an integrated multimodal travel demand and emission model of four policy strategies; presenting GHG and air pollutant reduction results at a very detailed level. Multiple policy outcomes are compared within a single modeling framework and study area. The results reveal that while no one demand mechanism is likely to reduce emissions to a level that meets policy-maker’s goals; a first-best pricing strategy that incorporates marginal social costs is the most effective emission reduction mechanism. Implementing such a mechanism may offer total emission reductions of up to 24 %. However, the efficacy of this strategy must be weighed against difficulties of establishing efficient pricing, a costly implementation, and substantial negative impacts to non-highway facilities. Decision makers must select a mixture of pricing and land use strategies to achieve emission goals on all road facilities.
The Influence of the Quasi-Biennial Oscillation on the Troposphere in Winter in a Hierarchy of Models. Part II: Perpetual Winter WACCM Runs

AbstractExperiments with the Whole Atmosphere Community Climate Model (WACCM) are used to understand the influence of the stratospheric tropical quasi-biennial oscillation (QBO) in the troposphere. The zonally symmetric circulation in thermal wind balance with the QBO affects high-frequency eddies throughout the extratropical troposphere. The influence of the QBO is strongest and most robust in the North Pacific near the jet exit region, in agreement with observations. Variability of the stratospheric polar vortex does not appear to explain the effect of the QBO in the troposphere in the model, although it does contribute to the response in the North Atlantic. Anomalies in tropical deep convection associated with the QBO appear to damp, rather than drive, the effect of the QBO in the extratropical troposphere. Rather, the crucial mechanism whereby the QBO modulates the extratropical troposphere appears to be the interaction of tropospheric transient waves with the axisymmetric circulation in thermal wind ...
Induction of mutations in the zebrafish with ultraviolet light.

Recessive lethal germline and specific locus somatic mutations were induced efficiently in the zebrafish by exposure of mature sperm to UV light. Mutagenesis of sperm yielded mosaic individuals: clones bearing novel mutations represented approximately 12–25% of the haploid germ cells and 25–50 % of the somatic tissue. Simple methods are described for the reliable identification and propagation of newly arising developmental mutations in zebrafish.
P450 induction alters paclitaxel pharmacokinetics and tissue distribution with multiple dosing

Paclitaxel (Taxol) is an effective agent against a broad range of human cancers. Studies on the metabolism and disposition of paclitaxel have shown that it is primarily eliminated via hepatic metabolism by P450 enzymes (2C8 and 3A4) to essentially inactive metabolites, and that biliary and gut transport by P-glycoprotein (PGP) as well as urinary elimination of the parent compound play relatively minor roles. Recent studies in vitro have shown that paclitaxel treatment increases the level of CYP2C8 and CYP3A4 in human hepatocytes as well as PGP in colon tumor cells. The data suggest that previous paclitaxel exposure may influence metabolism and elimination of subsequent doses. Further, since weekly paclitaxel dose schedules are becoming more common as opposed to the original every 21-day dosing, the likelihood of enzyme induction from previous doses impacting that from subsequent doses is increased. To study the potential for such sequence-dependent alterations in paclitaxel pharmacokinetics, we carried out pharmacokinetic studies in mouse plasma and tissues following day 1 and days 1 and 5 dosing at 20 mg/kg. Paclitaxel concentrations were determined by a sensitive LC/MS/MS assay out to 16 h post-dosing in plasma, liver, kidney, gut and heart. The effect of paclitaxel treatment on hepatic expression of PGP and P450 isoforms (CYP2C and CYP3A) was determined to elucidate the mechanism by which paclitaxel disposition is altered by previous drug exposure. Pharmacokinetic analysis of the data showed that plasma and tissue AUC values after treatment on day 5 following a dose on day 1 were between 50% and 74% of those determined following a single dose on day 1. The terminal elimination half-life was not different. Activity and protein levels for CYP2C in liver were elevated at 24 and 96 h after paclitaxel dosing. Cremophor EL, a carrier solvent for paclitaxel, also caused elevated CYP2C activity. Neither CYP3A nor PGP levels in liver were altered by paclitaxel or Cremophor EL treatment at the 24-h and 96-h time points. The levels of 6α-OH-paclitaxel in feces were increased on day 5 as opposed to day 1 while paclitaxel levels in feces were unchanged. The results of our studies showed that paclitaxel pharmacokinetics are altered by previous paclitaxel exposure up to 96 h earlier.
Anger, Depression, and Disability: A Path Analysis of Relationships in a Sample of Chronic Posttraumatic Headache Patients

Anger and depression are common affective concomitants of chronic headache. Previous research suggests that the affective component of headache may contribute to the patient's perceptions of the degree to which the headache is disabling. The present study examined the relationship between anger expression, anger suppression, depression, and headache-related disability (interference with function) in a sample of chronic posttraumatic headache patients. A path analytic model indicated a direct relationship between depression and perceived disability. Anger suppression and anger expression each had a direct influence on depression, but their effects on disability were mediated through depression. The results partially replicate a previous path analytic study of the relationships among these variables in a chronic headache sample.
Lifestyle modification in the management of obesity.

The World Health Organization has labeled obesity a global epidemic (1). In the United States, the prevalence of obesity (body mass index [BMI] ≥30 kg/m2) doubled from 15% in 1980 to 30% in 2000 (2). Despite the recent discovery of genetic factors that regulate body weight, an increase of this magnitude cannot be attributed to changes in our genes. The eating and activity habits of Americans have changed significantly during that time period and are the more likely culprits behind the nation’s fattening. Some have labeled ours a “toxic environment,” characterized by heavily advertised and readily available high-calorie foods, large portion sizes, and technological advances that implicitly discourage physical activity (3).
High-Brightness Lasers Using Integrated Optics

Monolithic, integrated optical designs for high-spectral-radiance, GaAs/GaAlAs laser sources are discussed. The sources described are designed to emit up to one watt of power in a CW, room-temperature operating mode. Specifically discussed are integrated optical techniques and devices for minimizing source spectral linewidth, maximizing source power, and achieving optimal output beam apodization.© (1978) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Inferring ecological disturbance in the fossil record: A case study from the late Oligocene of Ethiopia

Abstract Environmental disturbances profoundly impact the structure, composition, and diversity of modern forest communities. A review of modern studies demonstrates that important characteristics used to describe fossil angiosperm assemblages, including leaf margin type, plant form, plant diversity, insect herbivore diversity and specialization, and variation in herbivory among plant species, differ between early and late successional forests. Therefore, sequences of fossil floras that include a mix of early and later successional communities may not be appropriate to study long-term temporal trends or biotic effects of climate, latitude, or other variables. We conducted sedimentological, paleobotanical, and insect damage analyses at two contemporaneous late Oligocene (27–28 Ma) leaf localities in the Chilga Basin, northwest Ethiopia, to test the hypothesis that successional stage explains variation between the assemblages. The Guang River and Bull's Bellow fossil plant localities are stratigraphically equivalent and only 1.5 km apart, but they have no plant species in common. Sedimentary structures at Bull's Bellow suggest multiple episodes of deposition and a more disturbed environment than the single, featureless mudstone that composes the Guang River fossil unit. Bull's Bellow has a significantly higher percentage of plant species with toothed margins, lower plant and insect herbivore damage diversity, and less specialized herbivore damage than Guang. Furthermore, the nearest living relatives of many of the Bull's Bellow plant species are associated with early successional forests, whereas the Guang River plants are a mix of early and late successional species. Thus, the physiological and ecological attributes of the Guang flora are consistent with a more mature forest community, and the differences between the two floras emphasize the importance of collecting multiple floras from the same stratigraphic level in order to account for landscape-level ecological processes. More specifically, accurate estimates of diversity and feeding specialization in tropical, angiosperm-rich fossil assemblages are essential to address adequately the origin and persistence of relatively high species diversity in the modern tropics, and diversity differences between regions such as modern tropical Africa and South America.
Elasticity of Pseudomonas putida KT2442 Surface Polymers Probed with Single-Molecule Force Microscopy

Single-molecule force microscopy was used to study the effect of solvent polarity and ionic strength on the elasticity of bacterial surface polymers. Adhesion forces were measured between Pseudomonas putida KT2442 bacterial cells and silicon nitride tips of an atomic force microscope (AFM). Force−extension profiles were analyzed to determine the elasticity of the polymer chains in several solvents (water, formamide, methanol, 0.1 M KCl, and 0.01 M KCl). Adhesion peaks were fit to entropic-based, statistical mechanical, random walk formulations (the freely jointed chain (FJC) and the wormlike chain (WLC) models). The experimental data showed better agreement with the FJC (average R2 = 0.86 ± 0.20) than the WLC model (average R2 = 0.76 ± 0.22). The segment length was 0.18−1.0 nm in all five solvents using the FJC model, with about 60% of the chains having a segment length of 0.154−0.20 nm. The persistence length was 0.18−0.83 nm using the WLC model, with about 78% of chains having a persistence length of 0....
Shining new light on old principles: localization of evanescent field interactions at infrared-attenuated total reflection sensing interfaces.

A combined experimental and spectral ray tracing approach for identifying and evaluating evanescent field interactions with discrete surface deposits along a horizontal attenuated total reflection (HATR) element is presented. By experimentally depositing poly(styrene-co-butadiene) (PSCB) residues at fixed intervals along the measurement surface of a HATR crystal, distinct regions of evanescent field interaction with the surface deposits along the multi-reflection waveguide are visualized via infrared absorption features of PSCB. The infrared–attenuated total reflection (IR-ATR) measurements were confirmed by spectral ray tracing analysis simulating transmission–absorption spectra after modeling the polymeric surface deposits as thin-film IR absorbing cylinders. The presented analytical procedures and simulations provide a generic strategy for identifying and evaluating “active” sensing regions along ATR elements. Additionally, the simulated ATR setup along with the presented spectral ray tracing procedure...
Synoptic CCD Spectrophotometry of Pluto Over the Past 15 Years

Over the 15 years from 1980 to 1994, the same spectrometer has been used to obtain spectrophotometric observations of Pluto+Charon over the wavelength range from 0.5 to 1.0 μm. This time period spanned Pluto's perihelion passage in 1989, as well as the Pluto–Charon mutual event season. The data set is presented and a search made for variations in Pluto's methane absorptions and continuum slope correlating with Pluto's 6.4-day lightcurve as well as possible longer term secular evolution. Four quantities derived from Pluto's spectrum are examined for variation with Pluto's rotational phase. Although the depths of the methane bands are generally deeper away from the lightcurve minimum, they are found not to correlate in a simple way with the lightcurve, in contrast with the behavior of the stronger methane bands at longer wavelengths. This behavior implies that Pluto's CH4is not exclusively associated with the brightest or the darkest terrain, and that weak and strong methane bands are sensitive to different methane reservoirs on Pluto's surface. The wavelengths of CH4bands also change, being longest at the rotational phases where the CH4bands are deepest. The wavelength shifts can be attributed to variable concentration of CH4dissolved in N2ice. No statistically significant trend of bandwidth with longitude is detected. It is confirmed that the reddest slope of the continuum coincides with the darkest surface terrain. Examining spectral data pairs taken at similar Pluto longitudes, a modest but consistent secular trend is seen, with the depth of the 0.73-μm CH4absorption diminishing relative to that of the stronger 0.89-μm band. The observations are interpreted by means of Hapke scattering models. While unique solutions are not possible, it is found that the observed spectra can be matched by geographically diverse models possessing both methane rich and methane poor terrains. Terrain types proposed are a high albedo, CH4poor, N2dominated surface, a dark, red,tholin-rich surface, and a transitional zone, rich in CH4, with an intermediate albedo. The slight secular weakening of the 0.73-μm CH4band can be interpreted as resulting from differences between Pluto's southern and northern hemispheres or from a temporal evolution in the geographic proportions of the CH4rich and CH4poor terrains.
Co-Regulation of Student Motivation and Emergent Identity

In this article I outline a co-regulation model of identity that is based on an emergent interaction perspective derived from Vygotskian theory. I use this model to suggest the role of motivation in identity development. The co-regulation approach is one of many modern attempts (e.g., social cognitive, social constructivist, sociocultural) to understand how social and cultural influences might impact the development of the individual or perhaps transcend the individual. This article articulates a co-regulation model of emergent identity and provides an illustration of its potential for understanding how students might make school personally meaningful.
Escherichia coli DNA topoisomerase I catalyzed linking of single-stranded rings of complementary base sequences

Eco DNA topoisomerase I (E. coli ω protein) has been observed to catalyze the formation of double-stranded, covalently closed DNA from complementary single-stranded DNA rings, a novel reaction which is topologically forbidden without the enzyme-catalyzed breakage and rejoining of DNA backbone bonds. Incubation of a mixture of single-stranded PM2 DNA rings of complementary base sequences with ω yields a species with a sedimentation coefficient in an alkaline medium characteristic of a covalently closed circular double-stranded DNA. Buoyant density measurements in CsCl at alkaline pH also identify the product as a covalently closed duplex ring. If the ω-catalyzed reaction is stopped short of completion, highly negatively supercoiled molecules are formed which sediment more slowly in an alkaline medium than the final duplex product. As the reaction proceeds the mean sedimentation rate of the intermediates increases. This is in agreement with the expectation that the linking number between the two complementary rings increases gradually during the course of the reaction from zero to that of a relaxed covalently closed circular DNA duplex. The possible role of DNA topoisomerases in genetic recombination is discussed.
Risk Considerations for Fusion Energy

An assessment is made of the public and occupational health effects implied in the utilization of fusion reactors as a source of electricity. Three conceptual designs for TOKAMAK fusion reactors are used in the assessment. It was assumed in this analysis that a fusion plant will release 10 Ci/day of tritium to the atmosphere. Risk from waste management and accidents are estimated relative to risk of LWR's energy cycle. Comparison of the fusion occupational and public risk from coal, LWR, solar thermal and solar-photovoltaic plants has been undertaken. It is concluded that, compared to other fuel cycles, fusion can potentially have a favorable position with respect to risk.
Managerial Analysis of Doctoral Candidates and Professors: Research Attitudes and Interpersonal Relations

The authors feel that managerial analysis can contribute to the better understanding of many problems facing the modern university. This study, in analyzing the staffing problems of colleges of bus...
Association of methanogenic bacteria with flagellated protozoa from a termite hindgut

Epifluorescence microscopy was used to examine hindgut contents ofZootermopsis angusticollis (Hagen) termites for the presence of methanogenic bacteria, which can be identified on the basis of the fluorescence of the novel cofactors F420 and F350. Small, autofluorescent, rod-shaped bacteria of theMethanobrevibacter sp. morphotype were observed associated with three flagellates tentatively identified asTrichomitopsis termopsidis (Cleveland),Tricercomitus termopsidis Kirby andHexamastix termopsidis Kirby. Methanogens were not observed associated with any other protozoal morphotypes and were not numerous in the free-living state inZ. angusticollis hindgut fluid. Electron micrographs of thin sections of hindgut protozoa suggest methanogens are endosymbionts in the small trichomonad protozoa. Our observations are consistent with the finding of Odelson and Breznak that methane is a minor endproduct of the metabolism of termite gut microbiota.
Ganglion cell density in albino and pigmented rabbit retinas labeled with a ganglion cell-specific monoclonal antibody

Retinas from two rabbits, one normally pigmented and one albino, were labeled with monoclonal antibody AB5, which has been shown to be a specific marker for ganglion cells. This method obviates criteria for distinguishing among ganglion cells, displaced amacrine cells, and glia. Labeled cells were counted within small fields at some 2000 regularly spaced points on each retina. These counts were transformed to maps of ganglion cell density. In general, the density map for the pigmented retina was similar to those obtained by earlier studies with non-specific stains, thereby confirming the basic validity of most previous studies and demonstrating the applicability of AB5 labeling to work of this type. The ganglion cell density map of the albino retina was abnormal, showing a clear deficit of ganglion cells in the nasal portion of the visual streak. This result not only indicates that the albino anomaly has retinal effects, but also suggests a major impact on ganglion cells whose projections (in normal animals) are contralateral.