cssi/SciSciGPT-SciSciNet huggingface dataset:
Dispersion hardening in Al-V by plasma-jet spray-quenching☆

Abstract Al-V alloys have been quenched from the melt at rates of the order of 10 7 °C/sec by plasma-jet spraying. Considerably extended solid solubility of vanadium in aluminum is evident from X-ray lattice-constant measurements. Samples cold worked to a hardness three times that of annealed aluminum retained this hardness after high-temperature heat treatments, behavior typical of a dis persion-hardened alloy. Electron microscopy revealed a precipitated phase, subsequently identified as Al 11 V by electron diffraction.
Fossil wood from the middle Cretaceous Moreno Hill Formation: Unique expressions of wood mineralization and implications for the processes of wood preservation

Abstract The Cretaceous (Turonian) Moreno Hill Formation of west–central New Mexico provides an opportune isotaphonomic setting to study wood preservation because both carbonized and mineralized wood are commonly found within the same sediments and often within individual specimens. Petrographic, reflectance, maceral, and chemical analyses were used to compare and characterize mineralized and carbonized wood from the study site to investigate biases which influence mode of preservation. Coal (in the form of coal inclusions) is the most common form of fossil wood, and mineralized wood is also widespread in the formation. Two striking specimens of in situ coalified stumps are particularly informative because each includes a mineralized ring that appears to represent the former location of sapwood. Most of the mineralized samples are primarily composed of quartz, but a few specimens are predominantly mineralized with apatite. Calcite is present in charcoal samples where it permineralized, but never replaced organic carbon. This study points to two key factors that influence mineralization; wood permeability and the chemical alteration of the wood prior to incorporation into the sediment. The patterns of mineralization are consistent with hypothesized microbial involvement in the mineralization process. The coexistence of coal and mineralized tissues in some samples suggests that the processes of silicification and phosphatization co-occurred with coalification and that these processes are competitive within individual pieces of wood. As such, various stages of wood degradation have been preserved in mineralized samples from the Moreno Hill Formation. The study suggests that coal inclusions and mineralized wood/coal associations may also be common in other ancient sediments even though weathering may obscure their presence. Such information is important for paleoecological and paleoenvironmental studies which utilize the occurrence of fossil wood to help reconstruct floral composition or climatic conditions.
Adsorption and decomposition of formaldehyde on tungsten (100) and (111) crystal planes

Abstract The chemisorption of formaldehyde at ~100 K has been investigated on two single crystal planes of tungsten, W(100) and W(111). At low H2CO coverages, only H2 and CO are observed as thermal desorption products. At higher H2CO coverages both CH4 and CO2 are observed as additional desorption products. Work function and flash desorption measurements indicate that the dissociative adsorption of H2CO into H(ads) and CO(ads) is accompanied at higher surface coverages by the formation of other surface complexes. A detailed comparison of W(100) with W(111) indicates that crystallographic differences play a minor role in the surface catalyzed decomposition of H2CO by tungsten.
Examination of external apical root resorption with scanning electron microscopy

Abstract Objective External apical root resorption may be evident histologically but not visible radiographically until it is advanced. If working length is determined without considering this resorption, overinstrumentation or overfilling may occur. This study used scanning electron microscopy to examine the appearance and to compare the incidence of external apical root resorption in 40 teeth with differing pulpal and periapical diagnoses. Study design After extraction, 46 roots were sectioned horizontally 6 mm from the anatomic apex and prepared for scanning electron microscopy examination. Photomicrographs were scored by two blinded independent examiners. Apical resorption was categorized as: none, partial, or complete. Presence or absence of a funneling appearance of the resorption was also recorded. Results Kruskal Wallis showed a significant difference in resorption between groups; teeth with irreversible pulpitis/normal periapex had the least resorption. Duncan's multiple range test found radiographic apical lesions to have more resorption than those without lesions; teeth with necrotic pulps had more resorption than those with vital pulps. Conclusions Pulp necrosis with radiolucent apical pathosis is more likely to demonstrate resorption.
Screening for dementia and investigating its causes.

▪ Objective: To examine, from the perspective of primary care physicians, the value of mental status findings and ancillary tests in diagnosing dementia or its causes. ▪ Data Sources: Studies ident...
Automatic Analysis of Sleep Electroencephalograms by Hybrid Computation

An automated sleep electroencephalogram (EEG) analyzer has been designed and tested in an effort to eliminate tedious and variable human interpretation of experimental EEG data. Data is presented to a hybrid computer from EEG tapes recorded during experimental studies in a human sleep laboratory. Special analog filters are used to identify specific transient waveforms in the EEG. Bandpass filters are used to detect the rhythmical waveforms. The outputs of these filters are then processed by digital logic circuitry, whose algorithms emulate the rules used by human readers quantitating the level of sleep each minute according to the EEG pattem. Preliminary results give 89-percent correlation with a minute-by-minute comparison to the human evaluation of the same test EEG.
Global-Scale Waves in the Venus Atmosphere

The nature of global-scale waves that can exist in the atmosphere of Venus is examined. A linear three-dimensional model atmosphere with spherical geometry is used to study large-scale forced and free waves. Solutions are obtained numerically with grid points in the vertical and a spherical harmonic expansion in the horizontal. Observations have shown a global-scale traveling wave with phase speed near the cloud-top wind velocity. Global-scale wave modes are found to exist in the model at this velocity. When a radiative-dynamic cloud feedback is added to the model, the most unstable wave mode is found to have the same phase speed as the observed wave. The horizontal structure of this wave is consistent with the observed horizontal structure of the 'Y' feature seen in ultraviolet images of the Venus cloud top.
Who are the medical travelers and what do they want?: a qualitative study.

The ongoing debate on U.S. healthcare reform fueled by increasing cost and poor access to quality healthcare is spurring interest in medical travel. The topic of medical travel—going abroad to seek medical care—has been widely reported in various news outlets. This issue even resulted in a Senate Hearing before the Special Committee on Aging. Despite this popularity, very little empirical research has been conducted to describe and understand medical travelers. To fill this gap, the present study involves in-depth interviews of medical travel facilitators with extensive exposure to and communication with medical travelers. This article has multiple objectives. It aims to develop a demographic and psychographic profile of medical travelers and identify their underlying motives to seek medical care overseas. Based on these insights, it presents a list of propositions to be tested in further research. Finally, it offers practical implications for the healthcare industry.
Fluorodeoxyglucose positron emission tomography studies in diagnosis and staging of clinically organ-confined prostate cancer.

Abstract Objectives. To determine the value of 18-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) studies in the evaluation of patients with organ-confined prostate cancer. This imaging method has previously found little usefulness in localized prostate tumors because of excretion of the isotope into the urine, masking any lower urinary tract lesions. We evaluated this imaging modality using hydration, furosemide, and bladder emptying before the procedure to evacuate the nonspecific isotope in the urine. Methods. FDG PET scans were performed on 24 patients diagnosed with clinically organ-confined prostate cancer. No patient had received any prior treatments for the cancer. FDG PET scans were performed 1 hour after injection of 15 mCi of F-18 deoxyglucose. Patients were scanned from the base of the skull through the inguinal region (including the pelvis). Additional signal attenuation-corrected images of the inguinal region were acquired 30 minutes after intravenous injection of 40 mg of furosemide. The final diagnosis was made by histologic examination, correlative imaging studies, and/or clinical follow-up. Results. FDG PET studies were negative in 23 of the 24 organ-confined prostate cancers and the study was only faintly positive in 1 tumor (4.0% sensitivity). Conclusions. FDG PET is not a useful test in the evaluation of clinically organ-confined prostate cancer.
Pheromone Studies of the Twospotted Spider Mite. 3. Response of Males to Different Plant Tissues, Age, Searching Area, Sex Ratios, and Solvents in Bioassay Trials

Bioassay of a sex attractant produced by quiescent female deutonymphs of Tetranychus urticae Koch was improved if both male and female mites were reared and tested on hop-leaf tissue rather than bean-leaf tissue. Male response was greater on smaller leaf discs (5.5, 8.5 mm) than on larger discs (10.3, 21.0 mm) which fact indicated limited searching ability is a significant aspect of the bioassay technique. Adult males 0–3 days old responded slightly better than males 4–7 days old and 10–15% better than males 10 days old. Two males and 1 female quiescent deutonymph per leaf disc produced higher male response than 1♂:1♀, 2♂:2♀, 4♂:2'♀. Ether, water, and methylene chloride were tested as solvents for crude extraction of quiescent female deutonymphs. When tested over a range of concentrations, ether extract produced a mean male response of 18.6%, water extract 17.9%, and methylene chloride 13.7%.
Development of crystalline keratopathy after intravitreal injections of pegaptanib.

Anti-VEGF pharmacotheraphy has recently become popular for the treatment of retinal vascular diseases due to the stabilization or even improvement of vision with these agents. Herein, we report a rare corneal complication of anti-VEGF treatment with pegaptanib (Macugen; OSI Inc. and Pfizer Inc., New York, NY, USA).
Interactions of yeast ribosomal protein rpS14 with RNA.

Abstract Yeast ribosomal protein S14 (rpS14) binds to two different RNA molecules: (1) helix 23 of 18 S rRNA during its assembly into 40 S ribosomal subunits and (2) a stem-loop structure in RPS14B pre-mRNA to repress expression of the RPS14B gene. We used the three-dimensional structure of Thermus thermophilus ribosomal protein S11, a bacterial homologue of rpS14, as a guide to identify conserved, surface-exposed amino acid residues that are likely to contact RNA. Eight residues that met these criteria were mutated to alanine. Most of these mutations affected interaction of rpS14 with either helix 23 or the RPS14B stem-loop RNA or both. Assembly of 40 S ribosomal subunits and repression of RPS14B were also affected. S11 contains an extended carboxy-terminal domain rich in basic amino acids, which interacts with rRNA. We systematically evaluated the importance of each of the last ten amino acid residues in the basic, carboxy-terminal tail of yeast rpS14 for binding to RNA, by mutating each to alanine. Mutations in nine of these residues decreased binding of rpS14 to one or both of its RNA ligands. In addition, we examined the importance of four structural motifs in helix 23 of 18 S rRNA for binding to rpS14. Mutations that altered either the terminal loop, the G-U base-pair closing the terminal loop, or the internal loop affected binding of rpS14 to helix 23.
COST OF THE MARSHALL PLAN TO THE UNITED STATES

According to the Committe on European Economic Cooperation (C.E.E.C.), the Economic Recovery Program (E.R.P.) would cost $22.4 billion over the years 1948-51, of which about $3.1 billion would be financed by the International Bank or through other credit operations. Participating countries, it was estimated, would incur a deficit in the balance of payments with the American continent of $22.4 billion.'
A comparison of peripheral and central effects of CCK8 on water-reinforced operant responding

Systemic administration of cholecystokinin-octapeptide (CCK8) suppresses operant responding in water deprived rats, but it is unclear whether this effect is centrally or peripherally mediated. Rats were trained to press a lever for water in an operant conditioning chamber under a variable-interval schedule of reinforcement. After response rate stabilized injections were administered, and response suppression was measured by comparing injection response rate to baseline rate. Intracerebroventricular injections of CCK8 reduced lever pressing at relatively high doses (20 and 50 micrograms/rat). But in a direct comparison, the same dose of CCK8 (20 micrograms/rat) given intraperitoneally reduced responding significantly more than when given into the lateral ventricle. The suppressive effects of CCK8 (30 and 300 micrograms/kg i.p.) were significantly reduced by complete abdominal vagotomy. The effects of CCK8 (30 micrograms/kg i.p.) were blocked by pretreatment with the specific competitive CCK8 antagonist dibutyryl cyclic GMP (70 and 140 mg/kg i.p.), but not by the acetylcholine antagonist atropine (0.1 to 10 mg/kg i.p.). These data suggest that suppression by CCK8 of operant lever pressing in water-deprived rats is primarily mediated by vagal afferent fibers.
If at First You Don't Succeed Setting Passing Scores When More Than One Attempt Is Permitted:

For licensing and certification examinations designed to protect the public, passing incompetent candidates (false positives) is a more serious error than failing competent ones. Yet to avoid classification mistakes against individuals and subsequent litigation, current practices for these tests increase the relative risk of false positives. These practices are identified, and one that allows positive errors of measurement arising from multiple opportunities to pass the test is discussed in detail. Unsatisfactory ways to mitigate this problem are considered. Increasing the amount of testing or, if that is not feasible, raising the required passing score for repeaters is recommended.
Uniformity of Al2O3-ZrO2 Composites by Colloidal Filtration

Dispersion states of aqueous composite Al2O3/ZrO2 colloidal suspensions were studied by measuring particle size distribution as a function of pH. Mutual dispersion was achieved at pH values of 2.0 to 3.5. Consolidated composites formed by colloidal filtration reflected the uniformity of the colloidal state. The mean flexural strength (896 MPa) of the sintered compacts was 1.6 times that of bodies consolidated by isostatic pressing.
Toward the design and analysis of blind, bouncing robots

What kind of tasks are robots with extremely simple control laws capable of performing? Consider a point robot that navigates by aligning itself to a certain fixed angle relative to the environment boundary, then driving in a straight line. Even without knowing the robot's exact location, basic, noisy odometry and counting sensors can be used to narrow down the robot's possible locations over time. This paper describes methods of determining the possible locations of the robot after the robot has moved a sufficient distance or has impacted the boundary a sufficient number of times.
Technology requirements and readiness for very large aircraft

Common concerns of very large aircraft in the areas of economics, transportation system interfaces and operational problems were reviewed regarding their influence on vehicle configurations and technology. Fifty-four technology requirements were identified which are judged to be unigue, or particularly critical, to very large aircraft. The requirements were about equally divided among the four general areas of aerodynamics, propulsion and acoustics, structures, and vehicle systems and operations. The state of technology readiness was judged to be poor to fair for slightly more than one-half of the requirements. In the classic disciplinary areas, the state of technology readiness appears to be more advanced than for vehicle systems and operations.
Heat capacity and thermodynamic properties of strontium from 5 to 350 K

Abstract The heat capacity of pure strontium metal was measured by adiabatic-shield calorimetry from 5 to 350 K. At 298.15 K values of the thermodynamic functions are found to be: C p /cal th K −1 mol −1 = 6.402, S o /cal th K −1 mol −1 = 13.313, { H ( T ) − H o (0)}/cal th mol −1 = 1570.2, and { G o ( T ) − H o (0)}/ T cal th K −1 mol −1 = 8.047. Although the entropy at this temperature is in reasonable accord with another measurement (13.24 cal th K −1 mol −1 ) reported in the literature since initiation of these studies, serious differences in the temperature dependence of the heat capacity can be best explained by the assumption that the other sample contained approximately 10 moles per cent of strontium oxide.
Enhancement of Fish Feeding and Growth after an Increase in Minimum Flow below the Conowingo Dam

Abstract A summer minimum flow requirement was instituted in 1982 for the Conowingo Hydroelectric Dam, Maryland, where no such requirement existed previously. The response of fish to this minimum flow was assessed by monitoring food consumption and condition factor of three abundant, downstream species (white perch Morone americana, yellow perch Perca flavescens, and channel catfish Ictalurus punctatus), and by comparing the values from before and after the minimum flow was established. We also compared growth rates of white perch before and after the minimum flow was established by back-calculating length from otoliths. We found that fish condition (weight at length) was significantly greater for all species in years when the minimum flow was maintained. Similarly, growth rate (length at age) was significantly higher after the minimum flow requirement was instituted. Changes in food consumption appear to explain the differences in growth, as fewer empty stomachs and greater food consumption occurred afte...
Rapid eye movement definition and count: an on-line detector.

Abstract Rapid eye movement (REM—defined as abrupt, coordinate shifts of eye position) may be identified automatically by a detector designed in our laboratory. A conventionally obtained electrooculogram (EOG) records eye movement and simultaneously provides suitable electrical input for the REM detector. Detector criteria are based directly on our definition of REM (high speed leading edge slope, out of phase electrical change recorded from lateral canthi). Circuitry is straightforward, utilizing a combination of operational amplifiers and standard logic modules. Advantages are: (1) REMs may be counted when they occur too rapidly for visual identification; (2) only a REM with specified synchrony and eye transit velocity is identified: (3) EOG REM amplitude is not used as a criterion measure; and (4) the detector's output is in the form of a relay closure, which may perform several functions, such as operate cumulative recorders and trigger other circuits.
Nucleoside deaminase and adenosine deaminase activities in regenerating mouse liver.

Abstract The specific activities of nucleoside deaminase (cytidine aminohydrolase, EC 3.5.4.5) and adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) were determined in extracts of mouse liver following 70 % hepatectomy. There was an increase in the levels of these enzymes which preceded the onset of DNA synthesis by many hours. Enzyme levels remained elevated during the period of rapid DNA synthesis and for more than a week after the cessation of DNA synthesis. It is suggested that the increases in nucleoside deaminase and adenosine deaminase may be related to altered RNA metabolism in regenerating liver.
Characterization of ubiquinone from vegetative amoebae and mature sorocarps of the cellular slime mold, Dictyostelium Discoideum

Abstract 1. 1. Ubiquinone, or coenzyme Q, has been isolated from neutral lipid fractions of all developmental stages of the cellular slime mold, Dictyostelium discoideum . 2. 2. The ratio of Q-8 to Q-9 forms was about 2 : 1 in both vegetative and mature sorocarp cells. 3. 3. The amount of ubiquinone in the mature sorocarp is 2.3 mg/g dry weight or 1.5 per cent of the total lipid, a content which is among the highest reported in the literature for any organism.
DO THE RIGHT THING”: INNOVATION DIFFUSION AND RISK DIMENSIONS IN THE PASSAGE FROM CONVENTIONAL TO ORGANIC AGRICULTURE

Risk is quintessential in agricultural activities and the introduction of innovation in a farm always implies additional risks difficult to quantify and identify in advance. Surely farm’s internal and external sources of risk or kind of activities determine a complex entrepreneurial scenario but also psychological attitudes, feelings and behaviours of the individuals involved, a co-shared mentality and contextual culture may play a critical role as well. The case of the passage from conventional to organic agriculture exemplifies how a better understanding of “risk” and the related facets, perspectives and questions may provide relevant contributions to overcome the commonly shared idea of innate conservatism/impulsiveness in certain firms, economic sectors or class of entrepreneurs, to explain many cases of irrational resistance to innovation and to fill that frequent gap between technologists and farmers in the evaluation of the possibilities to adopt and implement also those innovations and new technologies necessary to achieve a more sustainable agriculture.
Carriage of methicillin-resistant Staphylococcus aureus at hospital admission.

Objectives:To measure the prevalence of, and to establish predictors for, the nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) at hospital admission. To evaluate mannitol-salt agar with oxacillin for the simultaneous detection and identification of MRSA from nasal swabs.Design:Three-month prospective case-control survey, with data collected from interviews and computerized databases. The criterion standard for MRSA detection was culture on Mueller-Hinton agar with oxacillin 6 μg/mL (National Committee for Clinical Laboratory Standards method).Setting:320-bed tertiary-care hospital.Patients:387 patients screened within 24 hours after admission, including 10 MRSA carriers (cases), 291 patients with no S aureus, and 86 patients with methicillin-susceptible S aureus.Results:The prevalence of MRSA nasal carriage was 2.6%, whereas the prevalence of carriage was 3.1% when both nasal and wound cultures were performed. The significant predictors of carriage were a prior detection of MRSA, open wounds, diabetes mellitus, treatments by injection, prior nursing home stays, visits at home by a nurse, and prior antibiotic treatments. Cases had stayed for longer periods in hospitals and had received longer antibiotic treatments within a year. Eighty patients (including the 10 cases) had diabetes, had been exposed to healthcare facilities within a year, and had antibiotics within 6 months. The sensitivity and negative predictive value of nasal swabs on mannitol-salt agar with oxacillin were 60% and 71%, respectively.Conclusion:MRSA carriage on admission to the hospital may be an increasing and underestimated problem. Further studies are needed to develop and validate a sensitive and specific prediction rule.
Improving planet-finding spectrometers

Adaptive optics (AO) systems correct for optical wavefront errors introduced by Earth's turbulent atmosphere, turning initially blurry images into intense diffraction-limited concentrations of light. The implementation of AO systems on the world's largest telescopes has revolutionized essentially all areas of astronomy ( 1 ). Instruments that receive a well-corrected beam of light can operate as if observing from space and thus benefit from an order-of-magnitude higher spatial and spectral resolution (see the figure). Given the benefits of working with nonfuzzy images, it may therefore be surprising to learn that one of the most important techniques for finding extrasolar planets, the Doppler radial velocity method, still uses “seeing-limited” observations—that is, measurements obtained without AO correction.
Joint and Cross Acceptances for Cross-Flow-Induced Vibration—Part II: Charts and Applications

Using closed-form and finite element solutions derived in Part 1 of this paper together with a standard commercial finite element structural-analysis computer program, the joint and cross acceptances for tubes and beams with different boundary conditions are calculated as a function of the correlation length up to 10 times the length of the structures. The results are presented in the form of charts. Steps are given to show how to use these charts together with standard commercial finite-element structural-analysis computer programs to estimate the responses of single and multi-span tubes and beams to cross-flow turbulence-induced vibration. The importance of cross-modal coupling for multi-supported beams is investigated. Examples are given.
Breath Hydrogen and Methane Responses of Men and Women to Breads Made with White Flour or Whole Wheat Flours of Different Particle Sizes

Objective: While it is well known that consumption of whole grain foods results in beneficial health effects, the great majority of Americans prefer bread made with white flour. Consumption of whole grain foods in high fiber menus may cause undesirable intestinal responses. The purpose of this study was to determine whether consumption of bread made with ultra fine ground whole wheat flour retained beneficial effects while reducing undesirable effects.Methods: Twenty-six men and women (31 to 55 years of age) consumed glucose solutions or bread made with white, whole wheat or fine ground whole wheat flour (1 g carbohydrate/kg body weight) in a Latin square design after two days of controlled diet. Breath methane and hydrogen were determined over the 24 hours after consumption of test foods.Results: Hydrogen and methane responses of men and women were similar. There were no significant differences in methane responses to the different treatments, but hydrogen response was increased by all breads (p<0.0001)....
Relative dissociation energies of protonated peptides by electrospray ionization/surface-induced dissociation

Relative dissociation energies (RDEs) are obtained for the major fragment ions produced by electrospray ionization/surface-induced dissociation of singly protonated triglycine, tetraglycine, leucine enkephalin, and leucine enkephalin arginine. A previously described data analysis method (Lim, H.; et al. J. Phys. Chem. B 1998, 102, 4753) is employed to analyze the energy-resolved mass spectra by subtracting out the distribution of energy transferred to the surface, integrating over the distribution of the incident ion energy, and taking into account the precursor ion initial internal energy and kinetic energy distributions. These variables are optimized by anchoring the RDE for the lowest energy fragment of a given precursor ion to its literature values and then using these optimized parameters to obtain the other RDEs. The RDEs of the four major fragments of triglycine vary from 2.4 eV for the b2 fragment ion to 6.0 eV for the a2 ion. The RDEs of the four major fragments of tetraglycine vary from 3.2 eV f...
The anthropology of modern human teeth: Dental morphology and its variation in recent human populations

By G. Richard Scott and Christy G. Turner II. New York: Cambridge University Press. 1997. 382 pp. ISBN 0-521-45508-1. $80.00 (cloth). © 1998 Wiley-Liss, Inc.
Magnitude of oceanic nitrogen fixation influenced by the nutrient uptake ratio of phytoplankton

The ratio of nitrogen to phosphorus in phytoplankton varies greatly with taxa and growth conditions. An ecosystem model suggests that the relative abundance of fast- and slow-growing phytoplankton controls the amount of new nitrogen added to the ocean. The elemental stoichiometry of sea water and particulate organic matter is remarkably similar. This observation led Redfield to hypothesize that the oceanic ratio of nitrate to phosphate is controlled by the remineralization of phytoplankton biomass1. The Redfield ratio is used universally to quantitatively link the marine nitrogen and phosphorus cycles in numerous biogeochemical applications2,3,4. Yet, empirical and theoretical studies show that the ratio of nitrogen to phosphorus in phytoplankton varies greatly with taxa5,6 and growth conditions7,8,9. Here we present a dynamic five-box ecosystem model showing that non-Redfield utilization of dissolved nitrogen and phosphorus by non-nitrogen-fixing phytoplankton controls the magnitude and distribution of nitrogen fixation. In our simulations, systems dominated by rapidly growing phytoplankton with low nitrogen to phosphorus uptake ratios reduce the phosphorus available for nitrogen fixation. In contrast, in systems dominated by slow-growing phytoplankton with high nitrogen to phosphorus uptake ratios nitrogen deficits are enhanced, and nitrogen fixation is promoted. We show that estimates of nitrogen fixation are up to fourfold too high when non-Redfield uptake stoichiometries are ignored. We suggest that the relative abundance of fast- and slow-growing phytoplankton controls the amount of new nitrogen added to the ocean.
S-adenosylhomocysteine hydrolase is an adenosine-binding protein: a target for adenosine toxicity

When adenosine deaminase activity is inhibited, low concentrations of adenosine are toxic to human lymphoblast mutants that are unable to convert adenosine to intracellular nucleotides. In order to identify the mediator of this cytotoxicity, we searched for a cytoplasmic protein capable of binding adenosine with high affinity. Such a protein was identified in extracts of human lymphoblasts and placenta as the enzyme S-adenosylhomocysteine hydrolase.
Inductive and space charge electric fields in a whistler wave packet

A low-frequency whistler wave packet is excited with a pulsed magnetic loop antenna in a large laboratory plasma (1 m diam\ifmmode\times\else\texttimes\fi{}2.5 m, ${\mathit{n}}_{\mathit{e}}$=7\ifmmode\times\else\texttimes\fi{}${10}^{11}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$, ${\mathrm{kT}}_{\mathrm{e}}$=1.3 eV, ${\mathit{B}}_{0}$=20 G). Multipoint (${10}^{4}$) measurements of the wave magnetic field, B(r,t), and 4D fast Fourier transformation, B(k,\ensuremath{\omega}), both verify the dispersion of oblique plane whistler modes and permit the calculation of the wave electric field, decomposed into its rotational (inductive) and irrotational (space charge) contributions, E(r,t)=${\mathbf{E}}_{\mathrm{ind}}$+${\mathbf{E}}_{\mathrm{sc}}$. The space charge density, \ensuremath{\rho}(r,t), for a whistler wave is also shown.
Studies on the frog's sartorius at different stages of activity.

Abstract Myosin was prepared from I g of frog's sartorius muscle and the yield was 20 mg to 30 mg of purified protein per gram wet weight tissue. The extractability of myosin was the same whether the muscle was at rest, in contraction or in fatigue. The adenosine triphosphate concentration was not changed in activity nor in fatigue and thus the extractability of myosin could be related to the unchanged concentration of adenosine triphosphate, but not to the state of activity of the muscle. The adenosine triphosphate activity and the concentration of sulfhydryl groups were the same in pairs of muscles either at rest and in contraction or at test and in fatigue. A fifteen fold decrease in the rate of relaxation of a muscle fatigued by single twitches suggests a progressive change in the relaxing factor system during fatigue.
A simple, rapid HPLC method for the concurrent measurement of cocaine and catecholamines in brain tissue samples

We describe a simplified HPLC method for the measurement of cocaine and catecholamines in the same brain tissue sample. Using this method to measure cocaine in the brain of rats which received either 10 or 20 mg/kg cocaine injections, we found substantial cocaine concentration differences between medial prefrontal cortex, striatum and limbic brain areas. Specifically, for each cocaine dose level there was a nearly 2-fold differential between cocaine concentration in the cortex as compared to limbic tissue. A shortcoming of many neurobehavioral studies of cocaine effects is the absence of brain cocaine measurements. The simplicity of the present method makes the measurement of cocaine and catecholamines from the same tissue sample a procedure which can readily be incorporated in the studies designed to evaluate the neurochemical effects of cocaine treatments.
Inhibition of proximal convoluted tubule transport by dopamine

Inhibition of proximal convoluted tubule transport by dopamine. Background Dopamine can produce a natriuresis and diuresis independent of changes in renal hemodynamics. However, previous studies have failed to demonstrate an inhibition of transport by dopamine in intact proximal convoluted tubules. Methods Rabbit proximal convoluted tubules were perfused in vitro with an ultrafiltrate-like solution and bathed in a serum-like albumin solution. Results In the present study, the addition of 10 -5 m dopamine to the lumen or bath of proximal convoluted tubules perfused in vitro had no effect on transport. In proximal convoluted tubules, addition of 10 -6 m bath norepinephrine increased the rate of volume absorption from 0.65 ± 0.08 to 0.93 ± 0.08nl/mm · min ( P -5 m luminal dopamine in the presence of bath norepinephrine inhibited the rate of volume absorption to 0.72 ± 0.10nl/mm · min ( P = 0.01). The inhibition in the rate of volume absorption by luminal dopamine in the presence of bath norepinephrine was completely blocked by the DA 1 antagonist, SCH 23390. The DA 1 agonist luminal 10 -5 m fenoldopam also inhibited volume absorption in the presence of bath norepinephrine, but the DA 2 agonist luminal 10 -5 m quinpirole was without effect. Bath 10 -5 m dopamine had no effect on volume absorption in the presence of bath norepinephrine. Conclusion Dopamine has no direct epithelial action on the proximal convoluted tubule. However, luminal dopamine antagonizes the stimulation in transport produced by norepinephrine. These studies suggest that luminal dopamine may play a role to modulate sodium transport in the presence of renal nerve activity.
PATTERN ANALYSIS FOR THE ULTRASONIC NONDESTRUCTIVE EVALUATION OF MATERIALS

In this paper the use of digital pattern recognition in ultrasonic nondestructive evaluation (NDE) of materials is examined. Emphasis is placed on identifying effective features from time and frequency domains, correlation functions and impulse responses to classify aluminium plate specimen into three major defect geometries: flat and angular cuts, and circular holes. A multi-stage classification procedure is developed which can further determine the angles and sizes for defect characterization and classification. The research clearly demonstrates that modern pattern analysis can significantly improve the nondestructive material evaluation capability of the ultrasonic methods.
Facial Hypertrophic Scarring from Pulsed Dye Laser

background. The 585-nm, 450-msec pulsed dye laser is widely used to treat benign vascular lesions. The biophysical interactive properties of this laser allow effective, precise small vessel ablation with very low incidence of pigmentary alteration and atrophic scarring side effects. objective. We are reporting a case of hypertrophic scar development on the upper lip of a patient whose facial hypertrophic port-wine stain was treated by pulsed dye laser. methods. The most effective energy fluence was determined by analysis of test areas treated at various fluences. This fluence was used for the initial full lesion treatment, with subsequent fluences chosen by treatment response at each 4-week follow-up visit. results. After the fourth treatment a hypertrophic scar developed on our patient's left cutaneous upper lip. conclusions. This hypertrophic scar developed after pulsed dye laser treatment because the patient did not follow posttreatment care instructions, and because the initial treatment fluences of 8.0–8.5 J/cm2 may have been too high.
RADIATION MEASUREMENTS OVER THE EQUATORIAL CENTRAL PACIFIC

Abstract During the Line Islands Experiment in spring 1967, surface shortwave and net radiation was continuously recorded at Palmyra, and Snomi-Kuhn infrared radiationsondes were released daily at the islands of Palmyra, (5°53′ N., 162°05′ W.) and Christmas (1°59′ N., 157°22′ W.) as part of an extensive surface and upper air observation program. Data are evaluated in terms of the diurnal march of the surface radiation balance and the radiation budget characteristics of the troposphere-ocean system. These direct measurements indicate a substantially larger surface net radiation than is expected from available climatic mean charts based on empirical formulas. Implications for the tropical heat budget are pointed out.
Differential involvement of RalA and RalB in colorectal cancer

Mutationally activated K-Ras can utilize a multitude of downstream effector proteins to promote oncogenesis. While the Raf and phosphoinositol 3-kinase effector pathways are the best-studied and validated, recent studies have established the critical importance of Ral guanine nucleotide exchange factor (RalGEF) activation of the RalA and RalB small GTPases in cancer biology. Due to recent evidence that the RalGEF-Ral pathway is necessary for the tumorigenic and metastatic potential of KRAS mutant pancreatic ductal adenocarcinoma (PDAC) tumor cells, we investigated whether or not Ral signaling was necessary for KRAS mutant colorectal cancer (CRC) tumor cell growth. As in PDAC, we found upregulated RalA and RalB activation in CRC tumor cell lines and tumors. Surprisingly we found antagonistic roles for RalA and RalB in the regulation of CRC tumor cell anchorage-independent growth. This observation contrasts with PDAC, where RalA but not RalB is necessary for PDAC tumor cell anchorage-independent growth. Our results emphasize cancer cell type differences in Ral function and hence the need for distinct Ral targeted therapeutic approaches in the treatment of CRC vs. PDAC.
Leptin Signaling in the Hypothalamus during Chronic Central Leptin Infusion

Using a rat model of chronic central leptin infusion in which neuropeptide Y neurons develop leptin resistance, we examined whether leptin signal transduction mechanism in the hypothalamus is altered during central leptin infusion. Adult male rats were infused chronically into the lateral cerebroventricle with leptin (160 ng/h) or vehicle via Alzet pumps for 16 d. In the leptin-infused group, the initial decrease in food intake was followed by a recovery to their preleptin levels by d 16, although food intake remained significantly lower than in artificial cerebrospinal fluid controls; and body weight gradually decreased reaching a nadir at d 11 and remained stabilized at lower level thereafter. Phosphorylated leptin receptor and phosphorylated signal transducer and activator of transcription-3 (p-STAT3) remained elevated in association with a sustained elevation in DNA-binding activity of STAT3 in the hypothalamus throughout 16-d period of leptin infusion. However, phosphorylated Janus kinase-2 was increased during the early part of leptin infusion but remained unaltered on d 16. Although hypothalamic suppressors of cytokine signaling-3 (SOCS3) mRNA levels were increased throughout leptin infusion, SOCS3 protein levels were increased only on d 16. This study demonstrates a sustained elevation in hypothalamic leptin receptor signaling through Janus kinase-STAT pathway despite an increased expression of SOCS3 during chronic central leptin infusion. We propose that an alteration in leptin signaling in the hypothalamus through pathways other than STAT3 and/or a defect in downstream of STAT3 signaling may be involved in food intake recovery seen after an initial decrease during chronic central leptin infusion.
Phosphorylation of Cdc20 is required for its inhibition by the spindle checkpoint

The spindle checkpoint delays anaphase until all chromosomes are properly attached to spindle microtubules. When the spindle checkpoint is activated at unattached kinetochores, the checkpoint proteins BubR1, Bub3 and Mad2 bind and inhibit Cdc20, an activator of the anaphase-promoting complex (APC). Here, we show that Xenopus laevis Cdc20 is phosphorylated at Ser 50, Thr 64, Thr 68 and Thr 79 during mitosis and that mitogen-activated protein kinase (MAPK) contributes to the phosphorylation at Thr 64 or Thr 68. Cdc20 mutants that are phosphorylation-deficient are able to activate the APC in X. laevis egg extracts. However, Cdc20 mutants in which any of the four phosphorylation sites were altered to Ala or Val failed to respond to the spindle checkpoint signal, owing to their reduced affinity for the spindle checkpoint proteins. This study demonstrates that the spindle checkpoint stops anaphase by inhibiting fully-phosphorylated Cdc20. Our results also have implications for the spindle checkpoint silencing mechanism.
Consuming Compassion AIDS, Figure Skating, and Canadian Identity

This article explores media coverage of male figure skaters who have died of AIDS-related illnesses, and the implication of the “AIDS crisis in figure skating” in ongoing struggles over HIV/AIDS po...
Flexibility of the RHO framework: A comparison of the Rb-exchange zeolite and the novel composition Rb24Be24As24O96·3.2 D2O

Abstract the structure of D 2 O-exchanged partially dehydrated Rb 24 Be 24 As 24 O 36 ·3.2 D 2 O was refined using a combination of neutron and X-ray powder diffraction data coupled with interatomic distance constraints. This material crystallizes with the framework of zeolite RHO [ I23, a = 14.01(1) A ]. The 24 Rb + are distributed as follows: The six double 8-ring sites (D8R) are fully occupied, two single 6-ring sites (S6R) are occupied by an average of 15 Rb + , and the remaining Rb + are randomly distributed over the 12 single 8-ring sites (S8R). The structure of the analogous D 2 O-exchanged, dehydrated aluminosilicate RHO, Rb 1 ]Al 10 Si 36 O 96 [ I 43 m, a =14.374(1) A ] was refined using neutron powder diffraction data. The Rb + ions are located, in order of preference, at the D8R and at only one of the S6R-sites at ( x,x,x ); x = 0.191(1). The relative framework distortion parameters for the elliptical 8-rings, Δ/ a , are 0.14 and 0.22 for the aluminosilicate and berylloarsenate, respectively. This variation of distortion with the unit cell parameter follows the same trend as that established for a number of materials with the RHO framework.
Innovation with Low-Ionization Plasma Sources for Enhanced Aluminum Processing

About 32 million tons of aluminum is melted every year. A significant amount is lost to dross during primary and secondary melting operations. Typically, to overcome the dross loss, either a nitrogen cover or a chemical cover is used over the molten metal. A new method, that uses a cover of low-ionization air, has proven to be effective in significantly reducing the dross. The method, low-ionization plasma melting, and its impact on the environment and on melting energy efficiency are discussed in relation to some of the other historical innovations for aluminum processing.
On the constructive episodic simulation of past and future events

We consider the relation between past and future events from the perspective of the constructive episodic simulation hypothesis, which holds that episodic simulation of future events requires a memory system that allows the flexible recombination of details from past events into novel scenarios. We discuss recent neuroimaging and behavioral evidence that support this hypothesis in relation to the theater production metaphor.
Thermal decomposition of 1-pentyl radicals at high pressures and temperatures

Abstract Shock-tube studies at the National Institute of Standards and Technology (NIST) and the University of Illinois at Chicago (UIC) have been used to examine the decomposition of 1-pentyl radicals in argon between (833–1130) K and (100–5000) kPa. High pressure limiting values of the product branching ratios appear to be approached at the highest pressures studied. Results agree well with a ‘best-fit’ model previously developed [1] and are consistent with an energy transfer value 〈ΔEdown〉 = (675 ± 100) cm−1 at 1000 K.
Initial Development of an Automated Task Analysis Profiling System

A program for automated task analysis is described. Called TAPS (task analysis profiling system), the program accepts normal English prose and outputs skills, knowledges, attitudes, and abilities (SKAAs) along with specific guidance and recommended ability measurement tests for nuclear power plant operators. A new method for defining SKAAs is presented along with a sample program output.
Short communication: Annatto in Cheddar cheese-derived whey protein concentrate is primarily associated with milk fat globule membrane

The yellow color of Cheddar cheese whey arises from a residual amount of annatto that partitions into the whey during Cheddar cheese manufacture. Bleaching of the color using hydrogen peroxide or benzoyl peroxide is often a prerequisite to produce an acceptable neutral-colored whey protein concentrate and isolate. However, the use of these strong oxidizing agents often generates off-flavors as a result of lipid oxidation and results in loss of nutritive value due to protein oxidation. The objective of this study was to determine the extent of partitioning of annatto between protein, milk fat globule membrane (MFGM), and aqueous (serum) phases of cheese whey so that a simple method can be developed to remove annatto from cheese whey. The MFGM was separated from Cheddar cheese whey using a recently developed novel method. Quantitative analysis of the distribution of annatto in the fat-free whey protein isolate (WPI), the MFGM fractions, and the serum phase revealed that annatto was not bound to the protein fraction but was mostly distributed between the serum phase and the MFGM fraction. The results showed that a colorless WPI or whey protein concentrate could be produced from Cheddar cheese whey by separation of MFGM from the whey, followed by diafiltration. This approach will negate the need for using bleaching agents.
Enzymatic production of pentoses from the hemicellulose fraction of corn residues

Abstract Three commercial xylanase preparations were evaluated as a sole enzyme source for the enzymatic production of pentoses from the hemicellulose fraction of corn husks and corn cobs. The hemicellulose fraction was obtained by extracting corn husks or corn cobs with 1.25 mol/l NaOH, and the alkaline extract was used as a substrate for enzymatic hydrolysis. Rapidase Pomaliq (Gist-brocades) was found to yield significantly more pentoses from corn husks and corn conb than Clarex ML (Genenor) or Validase × (Valley Research). Rapidase Pomaliq was capable of increasing the concentration of pentoses from an initial value of 106.5 to 210.6 g/kg dry matter of corn husks or 8.6 to 141.6 g/kg dry matter of corn cobs, respectively, under favorable conditions (480 min of reaction at pH 5.0 and 50 °C). Products of the enzymatic reaction were identified as arabinose, xylose, xylobiose, and xylotriose. The results of this study indicate that Rapidase Pomaliq, an enzyme preparation derived from Aspergillus niger and Trichoderma reesei , could serve as a sole enzyme source for the production of pentoses and xylooligosaccharides from corn residues.