cssi/SciSciGPT-SciSciNet huggingface dataset:
Novel differentially strained p-doped quantum well infrared detector

Abstract We propose a differentially strained p-doped quantum well infrared (IR) photodetector that achieves high performance specifications. We examine key device and material considerations for such a detector for near 10 μm detection. We calculate that through differential strain, this novel detector has improved gain and substantially reduced dark current over previous quantum well IR photodetectors, while being able to detect normal incident light.
Covalent structure of three phase-1 flagellar filament proteins of Salmonella

Using recombinant DNA techniques, the covalent structure was determined for three flagellar filament proteins produced by Salmonella serotypes with phase-1 antigens a, c and d. Comparison of the results obtained, together with previous results for antigen i, indicated an overall structure in which conservation of amino acid sequence was absolute at both ends of the molecule and proceeded inwards with progressively greater variation. Very few differences in nucleotide sequence were detected in regions of amino acid conservation, which suggested that these areas of the gene may be involved in regulatory functions.
Perturbation of ribosome subunit interaction by glutaraldehyde fixation

Ultracentrifugal analysis of ribosomal purity is complicated by the rapid reequilibration of ribosomes with their subunits, and this is further enhanced by the effects of hydrostatic pressure. Fixation of the ribosome system prior to ultracentrifugal analysis supposedly freezes the reequilibration, and thus tends to obviate these difficulties. However, no redistribution of the ribosome-subunit population must be allowed to occur during fixation. Thus, it is necessary that fixation be extremely rapid compared to the ribosome-subunit reequilibration, in order to avoid errors in analysis. It was the purpose of this investigation to make a direct experimental comparison of the rates of these two processes, fixation and ribosome-subunit reequilibration, using the stopped-flow technique with a light-scattering detector, under a variety of buffer environment readjustments. The following findings resulted from this study: (1) Fixation in Tris buffers could not be followed by light scattering because of interaction of glutaraldehyde with Tris, leading to continuous production of high molecular weight contaminants. (2) Polymerization of glutaraldehyde leads to increased ultraviolet absorption, which must not be confused with scattering changes. (3) Undialyzed ribosome solutions prepared by dissolving stock suspensions stored at high levels of magnesium and univalent electrolyte into a known standard buffer produced solutions having free Mg2+ levels lower than those of original buffer, complicating kinetic observations and threatening ribosome stability. (4) Addition of malonic acid as a buffer for Mg2+ largely eliminated this problem. (5) The kinetics of glutaraldehyde were measured quantitatively by studying the perturbation of ribosome association and dissociation kinetics produced during shifts of Mg2+ levels. (6) At fixative levels not producing coagulation, fixation kinetics can be competitive with those of association-dissociation. (7) Mass action effects like those of dilution can be caused by fixation, and can give rise to excess subunits, which may be mistaken for loose couples in original ribosome preparations.
Intraoperative neuro-monitoring corner editorial: The need for preoperative sep and mep baselines in spinal surgery: Why can’t we and our monitoring colleagues get this right?

Background: The majority of spinal surgeons now utilize intraoperative neurophysiological monitoring (IONM) during spinal procedures to limit the risk of inadvertent injury. Nevertheless, probably the most frequent error is the failure of the surgeon and IONM to obtain adequate preoperative baselines (e.g. before intubation or positioning).
Acoustic emission waveforms in composite laminates under low velocity impact

Hidden damage caused by foreign object impact in a composite structure, if left undetected, can grow and lead to a catastrophic failure of the structure. Detection of impact events and characterization of the degree of damage caused by them, preferably in real time, would be extremely helpful in safe continued operation of composite structures. In this paper, low velocity impact experiments are carried out on AS4/3501-6 [0/90]8S cross-ply graphite epoxy composite plates. An instrumented impact testing system is used to record the contact force and the surface motion at locations away from the impact point. The response of the plate due to localized sources is calculated using a modified laminate theory providing detailed information on the relationship between the impact load and the signals generated by the load. For thin plates, the far-field response is dominated by plate guided Lamb waves. It is shown that the occurrence of an impact loading can be easily detected from the recorded signals. Delamination damage, if any, can also be determined through careful analysis of the recorded waveforms. Practical applications of the technique in structural health monitoring will require careful investigation and elimination of environmental noise.
Designed surface residue substitutions in [NiFe] hydrogenase that improve electron transfer characteristics.

Photobiological hydrogen production is an attractive, carbon-neutral means to convert solar energy to hydrogen. We build on previous research improving the Alteromonas macleodii “Deep Ecotype” [NiFe] hydrogenase, and report progress towards creating an artificial electron transfer pathway to supply the hydrogenase with electrons necessary for hydrogen production. Ferredoxin is the first soluble electron transfer mediator to receive high-energy electrons from photosystem I, and bears an electron with sufficient potential to efficiently reduce protons. Thus, we engineered a hydrogenase-ferredoxin fusion that also contained several other modifications. In addition to the C-terminal ferredoxin fusion, we truncated the C-terminus of the hydrogenase small subunit, identified as the available terminus closer to the electron transfer region. We also neutralized an anionic patch surrounding the interface Fe-S cluster to improve transfer kinetics with the negatively charged ferredoxin. Initial screening showed the enzyme tolerated both truncation and charge neutralization on the small subunit ferredoxin-binding face. While the enzyme activity was relatively unchanged using the substrate methyl viologen, we observed a marked improvement from both the ferredoxin fusion and surface modification using only dithionite as an electron donor. Combining ferredoxin fusion and surface charge modification showed progressively improved activity in an in vitro assay with purified enzyme.
Higher order Bezier circles

Rational Bezier and B-spline representations of circles have been heavily publicized. However, all the literature assumes the rational Bezier segments in the homogeneous space are both planar and (equivalent to) quadratic. This creates the illusion that circles can only be achieved by planar and quadratic curves. Circles that are formed by higher order rational Bezier curves which are nonplanar in the homogeneous space are shown. The problem of whether it is possible to represent a complete circle with one Bezier curve is investigated. In addition, some other interesting properties of cubic Bezier arcs are discussed.
Interpopulation Variation in the Social Organization of Female Collared Lizards, Crotaphytus collaris

We tested the hypotheses that levels of intrasexual aggression and the social structure among neighboring females differed in two central Oklahoma populations of collared lizards, Crotaphytus collaris, and examined the extent to which variation in aggression might be related to differences in the availability of arthropods, elevated perches used by females to scan for prey, and crawlspace refugia. Because both the costs of aggression and access to resources may influence female fitness, we also compared growth and survival rates and the number of clutches produced. At Morningside Farms Ranch (MS), lizards occupied naturally-formed sandstone washes with naturally-sculpted irregular topographies, whereas they inhabited homogenous fields of boulders used to construct flood control spillways at the Arcadia Lake Dam (AL). The frequency of intrasexual aggression was markedly higher at MS, and groups of MS females had social hierarchies structured by size and age with older females defending territories, whereas no such social structure was apparent at AL. Moreover, experimental removal of individuals from female groups resulted in more pronounced changes by the remaining females at MS than at AL. Elevated perches and crawlspace refugia were much less abundant at MS. Arthropod availability was similar at the two sites, but at AL arthropods were clustered near the edges of rock patches where elevated perches overlooking adjacent grassy areas were particularly abundant. MS females showed lower rates of survival, and growth during the first year (when growth is highest) than AL females, whereas the number of clutches produced by females at the two sites was similar. Our results suggest that variation in the availability of perch rocks may have resulted in differences in female social structure at the two sites, and relaxed intrasexual competition for perches may have resulted in higher female fitness at AL.
Auditory illusion analogous to Baldwin illusion redux.

Two tones, differing only in duration, were used to define an interval. The perceived midpoint of the interval was displaced towards the tone of longer duration. Language: en
Quantitative evaluation of viral fitness due to a single nucleotide polymorphism in the Marek's disease virus UL41 gene via an in vitro competition assay.

Abstract Marek's disease, a T cell lymphoma, is an economically important disease of poultry caused by the Marek's disease virus (MDV), a highly cell-associated alphaherpesvirus. A greater understanding of viral gene function and the contribution of sequence variation to virulence should facilitate efforts to control Marek's disease in chickens. To characterize a naturally occurring single nucleotide polymorphism (SNP; AY510475 :g.108,206C > T) in the MDV UL41 gene that results in a missense mutation ( AAS01683 :p.Arg377Cys), bacterial artificial chromosome (BAC)-derived MDVs that differed only in the UL41 SNP were evaluated using a head-to-head competition assay in vitro. Monitoring the frequency of each SNP by pyrosequencing during virus passage determined the ratio of each viral genome in a single monolayer, which is a very sensitive method to monitor viral fitness. MDV with the UL41*Cys allele showed enhanced fitness in vitro. To evaluate the mechanism of altered viral fitness caused by this SNP, the virion-associated host shutoff (vhs) activity of both UL41 alleles was determined. The UL41*Cys allele had no vhs activity, which suggests that enhanced fitness in vitro for MDV with inactive vhs was due to reduced degradation of viral transcripts. The in vitro competition assay should be applicable to other MDV genes and mutations.
Wall shear stress is decreased in the pulmonary arteries of patients with pulmonary arterial hypertension: An image-based, computational fluid dynamics study

Previous clinical studies in pulmonary arterial hypertension (PAH) have concentrated predominantly on distal pulmonary vascular resistance, its contribution to the disease process, and response to therapy. However, it is well known that biomechanical factors such as shear stress have an impact on endothelial health and dysfunction in other parts of the vasculature. This study tested the hypothesis that wall shear stress is reduced in the proximal pulmonary arteries of PAH patients with the belief that reduced shear stress may contribute to pulmonary endothelial cell dysfunction and as a result, PAH progression. A combined MRI and computational fluid dynamics (CFD) approach was used to construct subject-specific pulmonary artery models and quantify flow features and wall shear stress (WSS) in five PAH patients with moderate-to-severe disease and five age- and sex-matched controls. Three-dimensional model reconstruction showed PAH patients have significantly larger main, right, and left pulmonary artery diameters (3.5 ± 0.4 vs. 2.7 ± 0.1 cm, P = 0.01; 2.5 ± 0.4 vs. 1.9 ± 0.2 cm, P = 0.04; and 2.6 ± 0.4 vs. 2.0 ± 0.2 cm, P = 0.01, respectively), and lower cardiac output (3.7 ± 1.2 vs. 5.8 ± 0.6 L/min, P = 0.02.). CFD showed significantly lower time-averaged central pulmonary artery WSS in PAH patients compared to controls (4.3 ± 2.8 vs. 20.5 ± 4.0 dynes/cm(2), P = 0.0004). Distal WSS was not significantly different. A novel method of measuring WSS was utilized to demonstrate for the first time that WSS is altered in some patients with PAH. Using computational modeling in patient-specific models, WSS was found to be significantly lower in the proximal pulmonary arteries of PAH patients compared to controls. Reduced WSS in proximal pulmonary arteries may play a role in the pathogenesis and progression of PAH. This data may serve as a basis for future in vitro studies of, for example, effects of WSS on gene expression.
Minimally invasive treatments for benign prostatic hyperplasia

Minimally invasive treatment (MIT) options for relief of symptoms attributed to benign prostatic obstruction (BPO) are becoming a more commonly used option for patients failing medical therapy. These MIT utilize an endoscopic approach to either ablate the obstructing prostatic tissue by a variety of techniques or to place a urethral stent to relieve BPO. The uniting factor in all MIT is to decrease or eliminate the current morbidity and complications that accompany the standard surgical therapy such as transurethral resection of prostate (TURP). Clinical trials evaluating the efficacy and morbidity of these MIT modalities, either alone or in comparison to TURP are reviewed. Level I evidence (randomized controlled trials) are present for most of the MITs and provide the strongest support for overall conclusions. Symptomatic improvements and quality of life (QoL) improvements for all of the MIT follow a similar pattern with a more pronounced improvement in outcomes for the more ablative techniques. Uroflowmetry and durability of outcomes, however, seem to demonstrate little differences amongst the therapies. Disparities existed in the morbidity observed with the different techniques. Urinary retention and urinary infections were more common in the ablative technologies. Rates of blood loss, urinary incontinence, sexual dysfunction and urethral strictures were observed at a lower rate in the MIT groups when compared to the rates observed in TURP. The morbidity and durability of TURP is higher and longer than that of MIT, respectively.
Gene Organization in Herpesvirus of Turkeys: Identification of a Novel Open Reading Frame in the Long Unique Region and a Truncated Homologue of pp38 in the Internal Repeat

Abstract The DNA sequence of a 4.792-kb fragment comprising 3.176 kb of the long unique region (U L ) and 1.605 kb of the internal repeat (IR L ) flanking U L of herpesvirus of turkeys (HVT) was determined. Three potential open reading frames (ORFs) and an origin of replication have been identified. ORF 1, which maps entirely within U L , has the capacity to code for an 82K protein, 731 amino acids long, which has a counterpart in Marek's disease virus (MDV) but not in other herpesviruses. ORF 2 has the potential to encode a protein consisting of 129 amino acids with a predicted M r of 13.5K which appears to be unique to HVT. ORF 3 is encoded entirely within IR L and codes for an 84 amino acids long protein with a predicted M r of 8.5K. ORF 3 shows significant homology with the C-terminal region of the MDV-1-specific phosphoprotein pp38 and its recently identified homologue in MDV-2. Northern blot analysis of RNA extracted from HVT-infected chick embryo fibroblasts identified a 5.6-kb RNA transcribed in a leftward direction toward U L spanning ORF 1, ORF 2, and ORF 3 and a 2.8-kb also transcribed leftward toward U L which spanned only ORFs 2 and 3. In addition, a 2.3- to 2.8-kb RNA family was transcribed rightwards through the origin of replication. In vitro transcription and translation of ORF 1 and ORF 3 resulted in the synthesis of polypeptides consistent with their expected M r but ORF 2 failed to produce any translation product.
Propagating viscous modes in a Taylor-Couette system

Abstract The nonequilibrium eigenmodes for the Taylor-Couette system are investigated in the narrow gap approximation. Propagating viscous modes are found under a wide variety of conditions.
A generalized inverse procedure for bifurcation problems

Abstract We give a systematic procedure for handling the linear aspects of the investigation of a bifurcation problem for the solutions of a boundary-value problem with ordinary differential equations. The method is an alternative method. The required projections are uniquely specified. We also use the related generalized inverse of the linear mapping. The technique is illustrated with two examples of periodic solutions of second-order nonlinear differential equations.
The relation between internal friction and tensile creep deformation on alumina ceramics

Abstract The properties of internal friction and tensile creep deformation of alumina ceramics are compared. The internal friction was measured by a torsion pendulum-type testing equipment, with increasing temperature up to 1450 °C. Tensile creep deformation was measured by a dead weight-type creep deformation testing equipment and an optical extensometer, at 1350, 1400 and 1450 °C. The internal friction increases exponentially with temperature, and shows no characteristic peaks with temperature scanning. The activation energy of internal friction obtained from changing the mechanical vibration frequency was 505–587 kJ mol −1 . The activation energy obtained from creep deformation was 584–684 kJ mol −1 . However, the grain size dependence of internal friction and creep deformation show different results. The grain-size dependence is significant for creep deformation, and the grain size exponent is 1.8-4.1. On the contrary, grain-size dependence is not clearly observed for internal friction.
CUES TO WORD SIMILARITY USED BY CHILDREN AND ADULTS: SUPPLEMENTARY REPORT

Use of letter and shape cues in visual recognition of 3- and 5-letter nonsense words by 1st- and 3rd-graders, and college students (ns = 50) was investigated. Shape cues were used less frequently than letters; use of shape cues decreased with increasing educational level of Ss and were more frequently used with longer words.
Measurement of systolic blood pressure using pulse oximetry during helicopter flight.

OBJECTIVE Monitoring of vital signs in critically ill patients during helicopter flight is difficult because of the noise and vibrations of the aircraft. We evaluated the use of a pulse oximeter to measure systolic BP intraflight. DESIGN Systolic BP measured by pulse oximetry was compared with systolic BP measured by the direct intra-arterial and the arterial occlusion methods intraflight. Systolic BP by pulse oximetry was measured by observing the return of the plethysmographic waveform of the pulse oximeter as the BP cuff ipsilateral to the pulse oximeter probe was slowly deflated. Arterial occlusion pressure was measured by observing the return of the intraarterial waveform as the BP cuff ipsilateral to the arterial cannula was slowly deflated. SETTING The study was performed during patient transport, intraflight. PATIENTS Ten critically ill patients were studied. INTERVENTIONS None MEASUREMENTS AND MAIN RESULTS Seventy-three sets of measurements were recorded. The best correlation (r2 = .99) was found between pulse oximetry and the arterial occlusion method. The indirect methods correlated better with each other than with direct intraarterial measurements. The noise and the vibrations of the helicopter did not significantly interfere with the operation of the pulse oximeter. CONCLUSIONS We conclude that a pulse oximeter that displays a plethysmographic waveform can accurately measure systolic BP intraflight.
Insights from a nonvocal learner on social communication.

Language is unique to humans. As a result, the neurobiological underpinnings of language are difficult to study in animal models. Fortunately, components of language, such as vocal learning, occur in other animals, including cetaceans, pinnipeds, elephants, bats, and several classes of birds,
Sea Lamprey International Symposium (SLIS II): Advances in the Integrated Management of Sea Lamprey in the Great Lakes

This paper provides a brief history of sea lamprey (Petromyzon marinus) control in the Great Lakes and introduces the second Sea Lamprey International Symposium (SLIS II). SLIS II was held during August 2000 to synthesize advances in sea lamprey management during the two decades since the first Sea Lamprey International Symposium (SLIS I) in 1979. SLIS I was convened by the Great Lakes Fishery Commission (the commission) to reflect on the effects of the first 20 years of sea lamprey control. Recommendations from SLIS I guided advances in the sea lamprey control program that are reported in this volume, including: improvements in chemical control methods; refinements in monitoring of the effectiveness of alternative methods; evaluations of changes in stream production; the search for natural controls; improvements in the understanding of sea lamprey population regulation; better estimation of alternative sources of sea lamprey; and improved understanding of the damage caused by sea lampreys. The most significant development emerging from SLIS I was the policy of Integrated Management of Sea Lamprey (IMSL) that was ultimately adopted by the commission in its Strategic Vision. IMSL was organized around the concepts of Integrated Pest Management (IPM) including: defining targets for control that optimize benefits; application of alternative techniques; and use of quantitative methods and systems approaches. Decision support tools have been developed to aid tactical control planning and to estimate strategic targets for sea lamprey management. The science reported in this volume points the way toward further improvements in the effectiveness and efficiency of sea lamprey management in the Great Lakes.
A comparison of three microbial assay procedures for measuring toxicity of chemical residues.

Public concern about environmental and health effects from the disposal of residues from the manufacture of agricultural and industrial process chemicals into landfills led to the passage of the Comprehensive Environmental Response, Compensation and Liability Act of 1980, commonly referred to as the “Superfund” Law. One method of defining the potential toxicity of these chemical residues is the use of bioassays, a number of which use bacteria as the test organism and have been proposed to assess the impact of chemical pollutants on the environment. Efforts were directed toward the establishment of short-term methods that are inexpensive, rapid, reproducible and sensitive. A major advantage of microbial toxicity tests over chemical analysis is their direct assessement of potential biotic impact without extrapolation from chemical analysis of uncertain completeness. It was the intent of this paper to evaluate the relative sensitivity, precision, and accuracy of three published microbial bioassay procedures for ascertaining their ability to define the toxicity potential at hazardous waste sites.
Mass and heat transfer in a circular tube with biofouling

Abstract A mathematical model of heat and mass transfer for a fluid flowing in a hollow cylinder with a tubular biofilm is developed. Results in dimensionless form are presented for mass transfer in isothermal laminar and turbulent flow and for heat transfer and combined heat-mass transfer in turbulent flow. For each system, the dominant resistance to the transport of heat and mass is determined. In a typical heat exchanger, the presence of a biofilm is found to decrease heat transfer significantly. For systems of interest, the biofilm thickness is nearly constant over the length of the tube in isothermal turbulent flow. In tubes with combined heat and mass transfer the thickness varies appreciably with the temperature of the fluid.
Transient experiences following hypnotic testing and special termination procedures.

Abstract For those who are responsive to hypnosis, the experiences can be unusual and involving. It is not surprising, therefore, that such experiences in response to tests of susceptibility may not be fully terminated when the hypnotic sessions end. In order to study the initial persistence of the effects, following administration of the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor and E. Orne (1962) and the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of Weitzenhoffer and E.R. Hilgard (1962), 107 college Ss were interviewed about their hypnotic experiences and subsequent experiences related to hypnosis. 72% of Ss reported feelings of relaxation and being rested following SHSS:C. Only 5% reported minor transient posthypnotic experiences following HGSHS:A, while 29% of Ss reported these feelings following SHSS:C. Except in 1 case, cognitive distortions or confusion were reported only following the more cognitively oriented SHSS:C by Ss who scored significantly higher...
The Cerebellum: A Neuronal Learning Machine?

Comparison of two seemingly quite different behaviors yields a surprisingly consistent picture of the role of the cerebellum in motor learning. Behavioral and physiological data about classical conditioning of the eyelid response and motor learning in the vestibulo-ocular reflex suggests that (i) plasticity is distributed between the cerebellar cortex and the deep cerebellar nuclei; (ii) the cerebellar cortex plays a special role in learning the timing of movement; and (iii) the cerebellar cortex guides learning in the deep nuclei, which may allow learning to be transferred from the cortex to the deep nuclei. Because many of the similarities in the data from the two systems typify general features of cerebellar organization, the cerebellar mechanisms of learning in these two systems may represent principles that apply to many motor systems.
Synthesis and Characterization of Water-Soluble Starch-Acrylamide Graft Copolymers

Abstract A series of water-soluble starch-polyacrylamide graft copolymers (ST-g-PAM) were prepared by Ce4+-initiated graft copolym-erizations of acrylamide (AM) onto starch (ST) dissolved in water at 30°C. The copolymers were found to contain 3-33% (wt) of ST. The structure of the copolymers, including the average number of grafts per chain and the efficiency of the initiator, was determined by acid-catalyzed degradation of the ST followed by size exclusion chromatography (SEC) analysis of the PAM chains and was found to be consistent with the presence or absence of free ST in the polymerization product prior to hydrolysis. The average number of grafts per starch molecule was found to be three or less, depending on conditions. The initiator efficiency (6–43%) was shown to decrease with increasing [Ce4+] and decreasing [AM], and this was found to be qualitatively in accord with the proposed mechanism of initiation and polymerization. The low efficiency was shown to be due, in part, to the low rate of react...
Modulation of K+ current by frequency and external [K+]: A tale of two inactivation mechanisms

Voltage-activated K+ currents and their inactivation properties are important for controlling frequency-dependent signaling in neurons and other excitable cells. Two distinct molecular mechanisms for K+ channel inactivation have been described: N-type, which involves rapid occlusion of the open channel by an intracellular tethered blocker, and C-type, which involves a slower change at the extracellular mouth of the pore. We find that frequency-dependent cumulative inactivation of Shaker channels is very sensitive to changes of extracellular [K+] in the physiological range, with much more inactivation at low [K+]out, and that it results from the interaction of N- and C-type inactivation. N-type inactivation enhances C-type inactivation by two mechanisms. First, it inhibits outward K+ flux, which normally fills an external ion site and thus prevents C-type inactivation. Second, it keeps the channel's activation gate open even after repolarization, allowing C-type inactivation to occur for a prolonged period.
Durability of AR Glass Fiber Reinforced Plastic Bars

Since the development of reinforced concrete over a century ago, engineers have constantly struggled with the corrosion problem of steel reinforcement. The new advances in the field of materials science have resulted in the development of fiber reinforced plastic (FRP) materials that could potentially be used as bars in reinforced concrete structures. The attractive features of this type of bars include high strength, light weight, and resistance to electrochemical corrosion. E-glass is the most widely used fiber material in FRPs; however, studies have shown that this type of fiber is susceptible to degradation in alkaline environments (i.e., concrete). This paper presents the results of a durability study on FRP bars made from an alternative glass fiber, alkali resistant (AR) glass, that could potentially improve the durability of FRP bars. A total of 160 bar samples were tested after exposure to corrosive solutions at temperatures of 25°C and 60°C. These solutions were designed to simulate accelerated exposure to adverse conditions in the field. Test variables included two matrix materials (polyester and vinyl ester), seven chemical solutions, and ultraviolet radiation. Moisture absorption by bars and associated changes in the mechanical properties were the focus of this study. In addition, 10 reinforced concrete beams were tested in flexure until failure, to examine the effects of exposure to concrete and deicing salts. Test results indicated that significant loss of strength could result from exposure of AR glass FRP bars to simulated aggressive field conditions. An analytical study based on diffusion models and Fick’s law was also conducted to predict the loss of strength. In the Fickian range of diffusion, the models predicted the loss of strength with a reasonable accuracy.
Phosphorylation of microsomal HMG CoA reductase increases susceptibility to proteolytic degradation in vitro.

Conversion of native, 97–100 kDa rat liver microsomal HMG CoA reductase to membrane-bound 62 kDa and soluble 52–56 kDa catalytically active forms was catalyzed invitro by the calcium-dependent, leupeptin- and calpastatin-sensitive protease calpain-II purified from rat liver cytosol. Cleavage of the native 97–100 kDa reductase was enhanced by pretreatment (inactivation) of microsomes with ATP(Mg2+) and liver reductase kinase (compared to protein phosphatase-pretreated controls). This was reflected in a loss of the 97–100 kDa species and an increase in the soluble 52–56 kDa species (total enzyme activity and specific immunoblot recovery).
A meta-analysis of gender gap in student achievement in African countries

We conducted a meta-analysis to examine gender differences in educational assessments in African countries. We analyzed the primary database of the Southern and Eastern Africa Consortium for Monitoring Educational Quality (SACMEQ) assessments. This study included a review of the relevant literature on meta-analysis techniques, and an overview of SACMEQ and gender issues in kindergarten (K)–12 in developing countries. The process of meta-analysis employed in this methodological study included searching, coding, calculation of effect sizes and their variances, weighting, confidence interval plots, Q test, funnel plots, and a discussion of results, implications, and future research. We found a small significant gender difference in mathematics in favor of boys and an insignificant gender difference in reading. Moreover, fertility rate was found to be an important predictor of gender gap in reading and math. Finally, we suggest a few implications for theoretical perspectives by connecting the key findings.
Effect of dietary fat on cholesterol turnover in old and new world monkeys.

Abstract Intravenously and orally administered doses of isotopic cholesterol were utilized to compare cholesterol turnover and absorption in squirrel, cebus, and rhesus monkeys fed cholesterol-free diets containing saturated (coconut oil) or unsaturated (safflower or corn oil) fat. The cholesterol turnover data for the comparison period fit a two-pool model, and the calculated turnover rates, PRΔ, were best compared between species on the basis of metabolic body size, kg0.75. Cebus and squirrel monkeys had rates of whole-body cholesterol turnover which were similar and twice that calculated for the rhesus monkey. The percentage of endogenous cholesterol reabsorbed tended to be less in squirrel monkeys than in cebus or rhesus monkeys, but no effect of dietary fat on absorption could be demonstrated with the procedure used, nor did dietary fat affect the overall excretion rate. The most remarkable difference was the decreased fractional removal of circulating cholesterol (metabolic clearance factor) associated with saturated fat feeding, reflecting an elevated plasma cholesterol level without a measurable difference in PRΔ. Neither the mass of total exchangeable cholesterol in pools A and B nor the flux between pools was changed with saturated fat feeding. A serious constraint of the method was the relative imprecision of the measure. Thus, the redistribution of the mass of circulating cholesterol (20–50 mg/kg) from the plasma compartment into other compartments within pool A or B of monkeys fed unsaturated fat could not be traced with certainty. Nonetheless, the data best support the suggestion that dietary polyunsaturated fat causes redistribution of cholesterol into tissue pools without altering total body balance.
Determination of trace metals in water using x-ray fluorescence spectrometry

A simple, rapid and accurate method for water analysis is proposed. The analytical procedure for the determination of Fe, Mn, Zn, Cu, Cd, As, Pb and Se in water in concentrations as low as a few ppM involves precipitation with a carrier of the metals by diethyldithiocarbamate (DDTC) or 1-(2-pyridylazo)-2-naphthol (PAN) and filitration through a Millipore filter. The precipitates collected on the filter disc are examined by X-ray fluorescence analysis. PAN is excellent for the determination of several metal ions at the ppM level, and DDTC can be used with tartrate as a masking agent if water samples contain large amounts of iron(III).
Nitric Oxide and Regulation of Heart Rate in Patients With Postural Tachycardia Syndrome and Healthy Subjects

The objective is to study the role of nitric oxide (NO) on cardiovascular regulation in healthy subjects and postural tachycardia syndrome (POTS) patients. Reduced neuronal NO function, which could contribute to a hyperadrenergic state, and increased NO-induced vasodilation, which could contribute to orthostatic intolerance, have been reported in POTS. In protocol 1, 13 healthy volunteers (33 ± 3 years) underwent autonomic blockade with trimethaphan and were administered equipressor doses of Nω-monomethyl-L-arginine (L-NMMA, a NO synthase inhibitor) and phenylephrine to determine the direct chronotropic effects of NO (independent of baroreflex modulation). In protocol 2, we compared the effects of L-NMMA in 9 POTS patients (31 ± 3 years) and 14 healthy (32 ± 2 years) volunteers, during autonomic blockade. During autonomic blockade, L-NMMA and phenylephrine produced similar increases in systolic blood pressure (27 ± 2 versus 27 ± 3 mm Hg). Phenylephrine produced only minimal heart rate changes, whereas L-NMMA produced a modest, but significant, bradycardia (-0.8 ± 0.4 versus -4.8 ± 1.2 bpm; P=0.011). There were no differences between POTS and healthy volunteers in the systolic blood pressure increase (22 ± 2 and 28 ± 5 mm Hg) or heart rate decrease (-6 ± 2 and -4 ± 1 bpm for POTS and controls, respectively) produced by L-NMMA. In the absence of baroreflex buffering, inhibition of endogenous NO synthesis results in a significant bradycardia, reflecting direct tonic modulation of heart rate by NO in healthy individuals. We found no evidence of a primary alteration in NO function in POTS. If NO dysfunction plays a role in POTS, it is through its interaction with the autonomic nervous system.
Using linear landmarks for path planning with uncertainty in outdoor environments

This paper presents two new approaches that enable the use of linear landmarks for planning paths with uncertainty in position in outdoor environments.
Calibration and Evaluation of an Objective Measure of Physical Activity in Preschool Children

Background The purposes of this study were 1) to establish accelerometer count cutoffs to categorize activity intensity of 3 to 5-y old-children and 2) to evaluate the accelerometer as a measure of children’s physical activity in preschool settings. Methods While wearing an ActiGraph accelerometer, 16 preschool children performed five, 3-min structured activities. Receiver Operating Characteristic (ROC) curve analyses identified count cutoffs for four physical activity intensities. In 9 preschools, 281 children wore an ActiGraph during observations performed by three trained observers (interobserver reli-ability = 0.91 to 0.98). Results Separate count cutoffs for 3, 4, and 5-y olds were established. Sensitivity and specificity for the count cutoffs ranged from 86.7% to 100.0% and 66.7% to 100.0%, respectively. ActiGraph counts/15 s were different among all activities (P < 0.05) except the two sitting activities. Correlations between observed and ActiGraph intensity categorizations at the preschools ranged from 0.46 to 0.70 (P < 0.001). Conclusions The ActiGraph count cutoffs established and validated in this study can be used to objectively categorize the time that preschool-age children spend in different physical activity intensity levels.
Modes of ventilation in early tetrapods: Costal aspiration as a key feature of amniotes

respects, and we propose that the changes in the mode of ventilation occurred in a stepwise fashion among the stem amniotes. We also argue that the change in ventilatory mode in amniotes related to changes in the postural role of the epaxial muscles, and can be correlated with the evolution of herbivory.
Straight-hair nevus syndrome: a case report with scanning electron microscopic findings of hair morphology.

ABSTRACT: Straight-hair nevus of the scalp is a distinct clinical entity. A case is reported and 2 other cases from the literature are reviewed. In our patient, specific morphology of the hair shown by scanning electron microscopy suggested a disorder in keratogenesis from loss of cuticular cells. Straight-hair nevus is probably a form of localized trichodysplasia.
Spatially amplifying modes of the Charney baroclinic-instability problem

We determine the circumstances under which baroclinic instability in the Charney model subjected to localized time-periodic forcing manifests itself as a wavetrain that oscillates at the source frequency and amplifies in space with distance from the source; analytical and numerical results describing the salient characteristics of such waves are presented. The spatially amplifying disturbance is a hitherto unsuspected part of the response to a pulsating source, and coexists with the more familiar neutral Rossby wavetrains; it is likely to play a role in a wide range of atmospheric and oceanic phenomena.The central results rely on a careful application of a causality criterion due to Briggs. These results illustrate a practical means of attacking spatial instability problems, which can be applied to a broad class of systems besides the one at hand. We have found that the Charney problem with positive vertical shear is not absolutely unstable, so long as the wind at the ground is non-negative. This implies that spatial instability and forced stationary-wave problems are well posed in an open domain under typical atmospheric circumstances.The amplifying waves appear on the downstream side of the source, have eastward (downstream) phase propagation and have wavelengths that increase monotonically with decreasing frequency, becoming infinite at zero frequency. When the surface wind is not too large, the spatial amplification rate has a single maximum near the frequency ωm = (f/N)Uz, where f is the Coriolis parameter, N is the stability frequency and Uz is the vertical shear; the rate approaches zero at zero frequency and asymptotes algebraically to zero at large frequency for any positive surface wind. Distinct Charney and Green modes do not appear until the surface wind is made very large. The amplification rate at ωm becomes infinite as surface wind approaches zero, suggesting a mechanism for the concentration of eddy activity.We also discuss the relationship of these results to the structure of low- and high-frequency atmospheric variability.
Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record‐Breaking Enterprise

On 20 April 2010, an explosion on the Deepwater Horizon oil drilling platform killed 11 people, and the subsequent blowout of the deepwater wellhead sparked one of the most costly oil spills in history. In the days and months that followed, researchers and disaster response crews flocked to the Gulf of Mexico to study, assess, and guide cleanup operations. In the AGU monograph Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record-Breaking Enterprise, editors Yonggang Liu, Amy MacFadyen, Zhen-Gang Ji, and Robert H. Weisberg pull together the results of the state-of-the-art rapid response research conducted during the Gulf oil spill. Here Eos talks to Yonggang Liu.
Gifted Education in the 21st Century

The beginning of the 21st Century has been marked by sizable shifts in our viewpoints on a number of factors that affect the education of gifted students. Such changes have been brought about by new knowledge, plus the reorganization of existing information. Five major dimensions can be noted; (1) Our view of the concept of intelligence, (2) Our view on who is gifted, (3) Our differentiation of curriculum for gifted students, (4) Our struggle over the competing values of equity vs. excellence in American education, and (5) the new easy access to the world's knowledge through technology, which makes life-long learning a possibility and changes the role of teacher and student.
Patient With Hypofibrinolysis-mediated Thromboembolism Converted to a Hypercoagulable/Hyperfibrinolytic State via Ventricular Assist Device Placement

Mechanical circulatory support with ventricular assist devices (VADs) for end-stage heart failure has been a focus of intense interest for nearly four decades. Despite improvements in VAD design and biomaterial composition, it is common to administer anti-coagulation (e.g., warfarin, anti-platelet agents) to prevent both device thrombosis and thromboembolism. We present a patient with pre-operative thrombophilia (pulmonary embolism, intracardiac thrombus) and hypofibrinolysis, who subsequently developed hypercoagulability with hyperfibrinolysis with normalization of clot lifespan after left VAD placement. Such complex patient–VAD–hemostatic-state interactions serve as the rationale for continuing investigation of the effects of mechanical circulation on the fibrinolytic system and thrombophilia.
Acute complications following gamma knife radiosurgery are rare.

Abstract BACKGROUND Gamma knife radiosurgery (GKR) is a safe and effective alternative to surgery for intracranial lesions. Most studies evaluating toxicity after GKR have concentrated on the delayed radiation effects. METHODS We retrospectively reviewed 835 consecutive GKR cases for early (within 7 days) neurological complications or death. RESULTS We identified a total of 18 patients (2.2%) who had a neurological event or death. Five (0.6%) patients developed new focal deficits, 12 (1.4%) patients experienced a seizure and there were three (0.4%) deaths. Two deaths were related to development of seizures and neurological deterioration. One death was caused by a respiratory arrest related to the patient’s primary cancer. Of the five patients with neurological deficits, none had a persistent deficit. In two cases the neurological deficits were due to an increase in edema. Whether this occurred as a result of the gamma knife treatment or was the natural progression of the tumor is unclear. CONCLUSIONS Complications after GKR are uncommon and the risk of a permanent deficit arising from an acute neurological event is exceedingly low.
The choking child- a life-threatening emergency. Evaluation of current recommendations

Recently, there has been much controversy in the pediatric literature concerning the appropriate emergency treatment of the choking child. The current recommendations of the American Academy of Pediatrics suggest a series of back blows followed by several chest thrusts. The research literature supporting these recommendations is reviewed. In addition, the data of investigators who disagree with this approach are presented. It is concluded that; although there are inadequacies in all of the existing research, there are no contraindications to the AAP recommendations. It is suggested that our focus, as pediatricians, should be on educating the lay public in the performance of a series of routine maneuvers that may be life-saving.
Public health and primary care: struggling to "win friends and influence people".

Why are the goals of public health and primary care less politically popular and financially supported than those of curative medicine? A major part of the answer to this question lies in the fact that humans often worry wrongly by assessing risk poorly. This reality is a significant obstacle to the adequate promotion of and investment in public health, primary care, and prevention. Also, public health’s tendency to infringe on personal privacy—as well as to call for difficult behavioral change—often sparks intense controversy and interest group opposition that discourage broader political support. Finally, in contrast to curative medicine, both the cost-benefit structure of public health (costs now, benefits later) and the way in which the profession operates make it largely invisible to and, thus, underappreciated by the general public. When curative medicine works well, most everybody notices. When public health and primary care work well, virtually nobody notices.
Re-accessing the Power of Art in the Discipline of Pan-African Studies

The visual arts and art history in general provide a powerful lens to understand the Diaspora. Regardless of what aspect of the Diaspora one examines, images of varying types can add depth to how someone can understand of power and experience. In this article I examine the role visual arts played in the Black Power movement and the positive impact it has had on the field of PanAfrican Studies. I accomplish this examination through the discussion of several works of art to illustrate the importance of incorporating more visual arts into the field and its curricula.