cssi/SciSciGPT-SciSciNet huggingface dataset:
Mercury Accumulation in Periphyton of Eight River Ecosystems

: In 2003, the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) program and U.S. Environmental Protection Agency studied total mercury (THg) and methylmercury (MeHg) concentrations in periphyton at eight rivers in the United States in coordination with a larger USGS study on mercury cycling in rivers. Periphyton samples were collected using trace element clean techniques and NAWQA sampling protocols in spring and fall from targeted habitats (streambed surface-sediment, cobble, or woody snags) at each river site. A positive correlation was observed between concentrations of THg and MeHg in periphyton (r 2 = 0.88, in log-log space). Mean MeHg and THg concentrations in surface-sediment periphyton were significantly higher (1,333 ng/m 2 for MeHg and 53,980 ng/m 2 for THg) than cobble (64 ng/m 2 for MeHg and 1,192 ng/m 2 for THg) or woody snag (71 ng/m 2 for MeHg and 1,089 ng/m 2 for THg) periphyton. Concentrations of THg in surface-sediment periphyton had a strong positive correlation with concentrations of THg in sediment (dry weight). The ratio of MeHg:THg in surface-sediment periphyton increased with the ratio of MeHg:THg in sediment. These data suggest periphyton may play a key role in mercury bioaccumulation in river ecosystems.
Reequilibration of olivine with trapped liquid in the Duluth complex, Minnesota

A 525-m-long drill core (DDH-221) through the Partridge River intrusion in northeastern Minnesota consists of mesocumulates and/or orthocumulates of troctolite, olivine gabbro, and olivine gabbronorite. The cumulus olivine, whose composition (Fo 31 to Fo 71 ) is a function of the amount of intercumulus liquid, followed an equilibrium crystallization path with this liquid. Estimates of the primary magmatic compositions of the olivine are Fo 57 to Fo 79 . None of the olivine in the drill core samples has retained an original cumulus composition (i.e., one that was in equilibrium with the parental magma). The plagioclase is strongly zoned, and the cumulus cores (An 59 to An 73 ) are thought to record crystallization from the parental magma.
Activation of proteinases with trypsin-like specificity from bovine and human lenses

Proteinases with apparent trypsin-like substrate specificity were present in extracts prepared from both bovine and human lenses. The enzymes from both sources required an incubation period of 10–25 hr at 34°C in the presence of 60 m m -NaCl or 5 m m -MgCl2 before any hydrolytic activity could be observed. Assays for BAPNA hydrolysis by bovine lens cortical extracts using this assay system showed one pH optimum at pH 6·5 and another at pH 8·0. The pH 8·0 activity was separated from the pH 6·5 activity by precipitation at pH 5·0. The precipitate, α1 crystallin, contained the pH 8·0 activity and still required an incubation period of 10–15 hr to activate the enzyme. Fractionation of bovine lens α1 crystallin by Agarose A-1·5 m gel filtration separated the pH 8·0 activity into three peaks eluting at molecular weights of 25000, 70000 and 900000 daltons. Fractionation of human lens cortical extracts by Agarose A-1·5 m gel filtration showed two peaks of pH 8·0 activity eluting at molecular weights of 25000 and 900000 daltons. Bovine lens α1 crystallin was activated by incubation with either magnesium or calcium at a concentration of 5 m m or sodium or potassium at 100 m m . No activity was induced, however, when extracts were incubated in the presence of either 5 m m -dithiothreitol or 1 m m -EDTA. These reagents appear to inhibit the activation of the enzyme, since fully active enzyme was no longer sensitive to either of these compounds. The activated enzyme has trypsin-like specificity, but was not inhibited by any of the classical trypsin inhibitors except benzamidine. This enzyme is clearly distinct from the bovine lens neutral proteinase and has not been reported previously, presumably because it exists in normal lens cortex in an inactive or inhibited state. The data suggest that this enzyme is active only in the presence of high cation levels and in the absence of thiol reducing agents. This situation, while not present in normal lens, does occur during cataract formation.
Correlation of AFM and SFA Measurements Concerning the Stability of Supported Lipid Bilayers

Phospholipid bilayers were studied by means of atomic force microscopy (AFM) and a surface force apparatus (SFA). The stability of the supported bilayers was described by the amount of irregularities in the topography of the membrane by means of AFM and by the occurrence of hemifusion in the SFA, which is an indicator of defective bilayers. The bilayers, composed of lipids having the same headgroup but different chain lengths in the two leaflets, were prepared by Langmuir-Blodgett deposition and transferred at different surface pressures. The topography of the supported bilayers in aqueous solution, as imaged by AFM, revealed an increasing number of defects in the supported lipid membranes with decreased deposition pressure of the outer lipid layer. These defects, which appeared in the form of monolayer and bilayer (self-assembled) thick holes within the membrane, were energetically favorable over an evenly depleted bilayer. We found that the quantity of these defects (holes of ≤0.5 μm diameter and covering up to 30% of the surface area) correlated well with the stability of the bilayers as measured by SFA, a truly complementary instrument.
Long Term Outcomes for LVAD Patients Who Underwent Speed Optimization Using Pre-Discharge Ramp Test

Purpose The influence of speed optimization on long term outcome among Continuous Flow (CF) Left Ventricular Assist Device (LVAD) pts is still unknown. Current guidelines recommend setting device speed that will ensure intermittent Aortic Valve (AV) opening during support. This study sought to determine the feasibility of achieving this parameter prior to discharge using a ramp test and its potential role in preventing long-term device complications. Methods and Materials A prospective study on pre-discharge speed optimization via Ramp Protocol was conducted post-device implantation. Right and left Heart Failure (HF), Gastrointestinal (GI) bleeding, arrhythmia, device thrombosis, and ECHO parameters of aortic insufficiency (AI) were collected. Results 37 pts had speed optimization Ramp tests before discharge with a mean follow-up time of 9.6±6.7 months. Mean age was 59±12 years old and 84% were male. 49% (n=18) were discharged with a speed that allowed for intermittent AV opening while 32% (n=12) were discharged with a closed AV. 19% (n=7) had AV surgery (Park stitch) at the time of implant. The frequency of right and left HF, ventricular arrhythmia and GI bleeding were similar among all 3 groups. 28% (n=5) of the AV opening group had device exchange due to obstruction to pump flow, whereas none of the 19 pts in the AV closed and AV surgery groups experienced device thrombosis (OR = 6.92, p=0.094). None of the pts in the AV opening group developed significant AI as compared to 1 pt who developed AI from the AV-closed group. Conclusions Intermittent opening of the AV via speed optimization was achieved in only 49% of the pts. Pts with AV opening may be at higher risk for developing obstructions to flow. Pts with intermittent AV opening may be better protected from developing significant AI. This study implies a differential speed setting for Bridge-To-Transplant pts since long-term consequences of AI is of less concern than protecting them from experiencing obstruction to pump flow events. Larger cohorts with longer follow up times are warranted.
Experimental Simulation of Contaminant Deposition on a Film-Cooled Turbine Vane Pressure Side With a Trench

An important issue in the use of coal- or biomass-derived synthetic gaseous (syngas) fuels is the deposition of contaminants on film cooled turbine surfaces, which alter cooling and aerodynamic performance and increase material degradation. The current study applied a new experimental technique that simulated the key physical aspects of contaminant deposition on a film cooled turbine vane. The depositing contaminants were modeled in a wind tunnel facility with a spray of molten wax droplets of a size range that matched the Stokes number of the contaminant particles in engine conditions. Most experiments were performed using a vane model with a thermal conductivity selected such that the model had the same Biot number of an actual engine airfoil, resulting in a cooler surface temperature. Some experiments were performed using an approximately adiabatic model for comparison. The film cooling design consisted of three rows of showerhead cooling at the leading edge and one row of body film cooling holes on the pressure side. Two designs of pressure side body film cooling holes were considered: a standard design of straight, cylindrical holes and an advanced design of “trenched” cooling holes in which the hole exits were situated in a recessed, transverse trench. The results showed thin deposits formed in the trench, with the thickest deposits on its downstream wall between coolant jets. Adiabatic film effectiveness levels were essentially unchanged by the presence of deposits for either film configuration. Deposit formation was strongly influenced by the model surface temperature with cooler surfaces inhibiting deposition. There was evidence of a threshold surface temperature above which deposits became significantly thicker.Copyright © 2011 by ASME
Role of an Ncap residue in determining the stability and operator-binding affinity of Arc repressor

Abstract The Arc repressor of bacteriophage P22 is a member of the ribbon–helix–helix family of transcription factors. Ser32 is a solvent-exposed position that serves a structural role as the N cap residue of α-helix B of Arc, but also serves a functional role because its side chain is packed close to the sugar–phosphate DNA backbone in the repressor–operator complex. The tolerance of this N cap position to amino-acid substitutions was probed by determining the repressor activity in vivo, the thermal stability and the operator-binding activity in vitro of a set of 13 mutant proteins. The stability of position-32 Arc variants, except for Cys32, correlated well with the frequencies observed for the corresponding residues at N cap positions in α-helices of other proteins. Cysteine was quite stabilizing at the helix-B N cap position in Arc, but surprisingly was the least frequent N cap residue in the protein database. This latter finding may reflect a hyper-reactivity of N cap cysteines, which makes them prone to chemical modification. In general, only Arc variants with small, uncharged residues at position 32 were active in vivo or showed strong operator binding in vitro. Based upon the results presented here, revised sequence alignments of the MetJ and NikR subfamilies with Arc and other ribbon–helix–helix proteins are proposed.
Evaluating the cost of therapy for restenosis: Considerations for brachytherapy

Costs have become increasingly important in medicine in recent years as demand for services has outstripped readily available resources. Clinical microeconomics offers an approach to understanding cost and outcomes in an environment of economic scarcity. In this article the types of costs and methods for determining cost are presented. In addition, methods for assessing outcome and outcome in relation to cost are developed. Restenosis after coronary angioplasty is a prime example of a clinical problem requiring economic evaluation. This is because it results in little serious morbidity except for recurrent chest pain, but it has serious economic consequences which occur some time after the original angioplasty. This makes the economic assessment of restenosis complicated. The application of health care microeconomic principles to brachytherapy for restenosis in the coronary arteries is presented.
Looking for Signs of Community College Arts and Sciences Faculty Professionalization in Searches: An Alternative Approach to a Vexing Question

To explore professionalization of community college faculty, this study uses data from case studies of searches for full-time arts and sciences community college faculty. The author concludes that there is little evidence of a unique profession and that on a continuum of professionalization community college faculty are more professionalized than K-12 teachers but less so than research university faculty. Further, the author argues that understanding what it means to be a professional in the context of a community college is more important than whether community college teaching is or should become a profession unique from its K-12 or university counterparts.
Kinetics of the reaction of CH3S with NO, NO2 and O2

Abstract We have used the laser-induced fluorescence technique to study the reactions of the methyl thiyl radical (CH 3 S) with NO, NO 2 , and O 2 as a function of pressure (1–400 Torr N 2 or SF 6 ) and temperature (25–238°C). Rate constants for the reaction with NO are in the transition region between the low- and high-pressure limits and are fit using an expression developed by Troe. The resulting Arrhenius expression is k ∞ (±2σ) = (1.81 ± 0.84) × 10 −12 exp[(1800 ± 320 cal/mol)/ RT ] cm 3 /s. The rate constant for the reaction of CH 3 S with NO 2 is essentially pressure independent and yields k = (8.3 ± 1.4) × 10 −11 exp[(160 ± 120 cal/mol)/ RT ] cm 3 /s. The reaction with O 2 is too slow to measure in our system; we estimate that k ⩽ 2 × 10 −17 cm 3 /s at room temperature.
Right and left cerebral hemisphere damage and tactile perception: performance of the ipsilateral and contralateral sides of the body.

Abstract Patients with lateralized brain lesions were compared with respect to contralateral and ipsilateral tactile-perceptual difficulty as well as overall performance on such tasks. Results showed that patients with right hemisphere brain damage were more impaired on the contralateral and ipsilateral sides of the body than were patients with lesions of the left hemisphere. Total errors were also greater in the right than left brain-damaged group. Findings suggest the right hemisphere is pre-eminent in subserving tactile perception on both sides of the body.
Factorization of matrix functions with subgroup supported Fourier coefficients

Abstract It is proved that if a Wiener class matrix function on a connected compact abelian group admits a factorization with respect to a connected compact abelian supergroup, then it admits a factorization with respect to the original group. In particular, all factorization indices are characters of the original group. An illustrative example is considered.
Ribozyme recognition of RNA by tertiary interactions with specific ribose 2'-OH groups.

SHORTENED forms of the group I intron from Tetrahymena catalyse sequence-specific cleavage of exogenous oligonucleotide substrates1,2. The association between RNA enzyme (ribozyme) and substrate is mediated by pairing between an internal guide sequence on the ribozyme and a complementary sequence on the substrate1,3,4. RNA substrates and cleavage products associate with a binding energy greater than that of base-pairing by ∼4 kcal mol−1 (at 42°C), whereas DNA associates with an energy around that expected for base-pairing5–9. It has been proposed that the difference in binding affinity is due to specific 2′-OH groups on an RNA substrate forming stabilizing tertiary interactions with the core of the ribozyme, or that the RNA-RNA helix formed upon association of an RNA substrate and the ribozyme might be more stable than an RNA-DNA helix of the same sequence6. To differentiate between these two models, chimaeric oligonucleotides containing deoxynucleotide residues at successive positions along the chain were synthesized, and their equilibrium binding constants for association with the ribozyme were measured directly by a new gel electrophoresis technique5. We report here that most of the extra binding energy can be accounted for by discrete RNA–ribozyme interactions, the 2′-OH group on the sugar residue three nucleotides from the cleavage site contributing the most interaction energy. Thus, in addition to the well documented binding of RNA to RNA by base-pairing10–14, 2′-OH groups within a duplex can also mediate association between RNA molecules.
Vapor-phase self-assembly of carbon nanomaterials

Abstract A variety of carbon structures are produced in an electric arc discharge with an anode composed of carbon, cobalt, and sulfur. Single and multiple layered carbon nanotubes, as well as partially filled nanowires and bamboo-shaped carbon compartments, are found in different regions of the soot inside the chamber. Sulfur plays an important role in forming these carbon nanomaterials.
Aspheric optical elements for extended depth-of-field imaging

We provide experimental verification of the performance of an optical-digital imaging system that delivers near diffraction limited imaging over a wide depth of field. A custom aspheric optical element is used to modify an incoherent optical system so that the generated optical image is nearly independent of misfocus-induced blur. The resulting image, called an intermediate image, is not spatially diffraction limited. Digital processing of the intermediate image produces a final image that forms a close approximation to the diffraction limited image. The combined effect of the optical-digital system is to image objects independently of focus or range, that is, the system has an extended depth of field.
Ureteral ligation induces Fos expression in the dorsal horn.

Abstract To describe a sympathetic afferent circuit, the left ureter was ligated in anesthetized rats for 1.5–2 h followed by immunocytochemical processing to localize expression of either the immediate early gene (IEG) c- fos or Krox-24 in the spinal cord or dorsal root ganglia (DRG). No IEG expression was detected in DRG. Both Fos and Krox-24 expression was found in the dorsal horn. More Fos immunocytochemically stained cells were found in the dorsal hom both ipsi- and contralateral to the ligated ureter at spinal segments T 10 –T 13 after ureteral ligation than after either sham ligation or anesthesia control procedures. More Fos stained cells were in the dorsal horn ipsilateral to the ligated ureter than on the contralateral side. The Fos staining patterns in the dorsal horn of ligated and sham-ligated animals were similar with most labeled cells in dorsomedial portions of laminae I and II. In contrast, the Fos staining pattern in the dorsal horn in anesthetized animals (unoperated controls) was noticeably different from operated animals with the most Fos cells in the ventrolateral part of laminae I-II. These results indicate that (1) Fos immunocytochemistry may be useful for tracing sympathetic afferent pathways, (2) the sensory pathway activated by ureteral ligation enters the spinal cord at lower thoracic levels, where renal and upper ureteral afferents are terminating, and (3) some of this sympathetic afferent pathway is located contralateral to the stimulated kidney. Neurons activated by ureteral ligation in the contralateral dorsal horn may mediate reno-renal reflexes.
ALTERING IMPULSIVE DECISION MAKING WITH AN ACCEPTANCE-BASED PROCEDURE

Abstract Delay discounting is one facet of impulsive decision making and involves subjectively devaluing a delayed outcome. Steeply discounting delayed rewards is correlated with substance abuse and other problematic behaviors. To the extent that steep delay discounting underlies these clinical disorders, it would be advantageous to find psychosocial avenues for reducing delay discounting. Acceptance-based interventions may prove useful as they may help to decrease the distress that arises while waiting for a delayed outcome. The current study was conducted to determine if a 60–90 minute acceptance-based training would change delay discounting rates among 30 undergraduate university students in comparison to a waitlist control. Measures given at pre- and posttraining included a hypothetical monetary delay discounting task, the Acceptance and Action Questionnaire-II (AAQ-II), and the Distress Tolerance Scale. Those assigned to the treatment group decreased their discounting of delayed money, but not distress intolerance or psychological inflexibility when compared to the waitlist control group. After the waiting period, the control group received the intervention. Combining all participants’ pre- to posttreatment data, the acceptance-based treatment significantly decreased discounting of monetary rewards and increased distress tolerance. The difference in AAQ-II approached significance. Acceptance-based treatments may be a worthwhile option for decreasing delay discounting rates and, consequently, affecting the choices that underlie addiction and other problematic behaviors.
Removal of benzo(a)pyrene diol epoxide (BPDE)-DNA adducts as a measure of DNA repair capacity in lymphoblastoid cell lines from sisters discordant for breast cancer.

The mutagen sensitivity assay is one of the approaches used to investigate individual DNA repair capacity. This method is based on the premise that after in vitro treatment with a test mutagen, DNA from subjects with defective repair will be more damaged than DNA from those with an efficient repair system. However, very little is known about unmeasured processes that occur between cell treatment and final assessment of DNA damage. To develop a more precise assay, we modified the traditional mutagen sensitivity assay to also include measurement of DNA damage after culturing cells in the absence of mutagen. First, we treated apparently normal and xeroderma pigmentosum lymphoblastoid cell lines with various doses of benzo(a)pyrene diol epoxide (BPDE) and harvested cells at different time points. A polyclonal antiserum against BPDE-DNA was used to quantitate levels of adducts by immunoslot-blot and immunohistochemistry. Selected conditions included treatment with 10 μM BPDE, a 4-hr culture in mutagen-free medium, and immunohistochemical measurement of BPDE-DNA adducts. The method was then applied in a pilot study to 50 lymphoblastoid lines from sisters discordant for breast cancer. There was no significant difference between cases and controls in the level of BPDE-DNA adducts in lymphoblasts harvested immediately after BPDE treatment. However, after a 4-hr culture in mutagen-free medium, the level of adducts was significantly higher (P = 0.006) among cases than in controls. There was a two-fold increase in mean adduct removal in lines from nonaffected as compared to affected sisters (44% and 22% decrease, respectively). DNA repair capacity was predictive of case status (P = 0.04) in logistic regression analysis. This method, which can be easily applied to large numbers of samples, should be useful in studies to investigate the role of DNA repair in cancer risk. Environ. Mol. Mutagen. 40:93–100, 2002. © 2002 Wiley-Liss, Inc.
Higher-Order Linear-Time Unconditionally Stable Alternating Direction Implicit Methods for Nonlinear Convection-Diffusion Partial Differential Equation Systems

We introduce a class of alternating direction implicit (ADI) methods, based on approximate factorizations of backward differentiation formulas (BDFs) of order p≥2, for the numerical solution of two-dimensional, time-dependent, nonlinear, convection-diffusion partial differential equation (PDE) systems in Cartesian domains. The proposed algorithms, which do not require the solution of nonlinear systems, additionally produce solutions of spectral accuracy in space through the use of Chebyshev approximations. In particular, these methods give rise to minimal artificial dispersion and diffusion and they therefore enable use of relatively coarse discretizations to meet a prescribed error tolerance for a given problem. A variety of numerical results presented in this text demonstrate high-order accuracy and, for the particular cases of p=2,3, unconditional stability.
Feasibility of online divergent thinking assessment

The project examined creative thinking in online settings.The goal was to aid creative thinking research by increasing ecological validity.Online administration had no detrimental affect on divergent thinking.Imposition of time limits effectively reduced individual differences in time-on-task, fluency, and originality.Divergent thinking was stable across two different online samples. Two studies explored whether assessment of creative thinking is feasible using web-based methods and how participants reacted to the imposition of time constraints in online settings. Sixty-five participants (Study 1) completed a verbal fluency task and a divergent thinking task, half of the participants doing so over the Internet. Online administration did not affect originality, but led to slightly fewer responses overall. This demonstrated that online administration of creative thinking is indeed feasible and reliable, though steps must be taken to ensure participants exhaust all possible responses. To test the effect of time limits on responses, 84 participants (Study 2) completed a verbal fluency task and three divergent thinking tasks online, half of the participants doing so under time pressure (3min). There were significant interactions between time limits and task content for both time-on-task and fluency variables, but the task type was the dominant force in the varying fluency and time-on-task scores. Originality was not significantly affected by time limits, but did vary across tasks. In all cases the results illustrate that assessment of divergent thinking, as a proxy of creative thinking, is feasible using online methods. Implications for future work in this area are discussed.
Canopy cover effects on soil nitrogen mineralization in northern red oak (Quercus rubra) stands in northern Lower Michigan

Abstract It has been shown in many studies of nutrient cycling in forest ecosystems that clearcutting creates increased nitrogen (N) mineralization in the soils. However, little is known about the direction and rate of change of N mineralization following various levels of canopy removal in northern red oak ( Quercus rubra L.) stands, despite the fact that an understanding of these processes may have important implications for self-replacement in such stands. Accordingly, a series of experimental plots was manipulated to produce various levels of canopy cover, i.e. clearcut, 25% (50% during first sampling year), 75%, and uncut in northern red oak stands in northern Lower Michigan. Net N mineralization and nitrification in the top 15 cm of mineral soil were examined during the first two growing seasons (1991–1992) following the treatments, using an in situ buried bag technique. Net N mineralization over the course of both growing seasons (May–October) ranged from 79 kg ha −1 per growing season in the clearcut treatment to 22 kg ha −1 per growing season in the uncut stand. The highest net N mineralization was observed in the clearcut with the highest increase of soil temperature. Net N mineralization was significantly higher in the partial canopy cover treatments compared to the uncut stand during the second growing season, but not in the first growing season. Nitrification was unaffected by factors such as increased soil pH, elevated NH 4 + availability, and soil temperature after canopy removal. The results indicated that even small amounts of canopy removal (leaving 75% canopy cover) are sufficient to cause substantial increases in the amount of N available for the establishment and growth of understory oaks.
Knowing a word (sense) by its company

Supervised word sense disambiguation requires training corpora that have been tagged with word senses, and these word senses typically come from a pre-existing sense inventory. Space limitations imposed by dictionary publishers have biased the field towards lists of discrete senses for an individual lexeme. This approach does not capture information about relatedness of individual senses. How important is this information to knowing which sense distinctions are critical for particular types of NLP applications? How much does sense relatedness affect automatic word sense disambiguation performance? Recent psycholinguistic evidence seems to indicate that closely related word senses may be represented in the mental lexicon much like a single sense, whereas distantly related senses may be represented more like discrete entities. These results suggest that, for the purposes of WSD, closely related word senses can be clustered together into a more general sense with little meaning loss. This talk will describe the relatedness of verb senses and its impact on NLP applications and WSD components as well as recent psycholinguistic research results.
Mössbauer Study of Dehydro-N N′ N″-Trialkylguanidino-hexacarbonyldi-iron(O) and Related Compounds

Abstract The application of recoilless gamna ray absorption (Mossbauer effect) to organometallic chemistry dates back well over ten years, and its progress is described in a number of review articles and texts. 1–4 The usefulness of this tool has been enhanced by the elaboration of the concept of the additivity of isomer shifts from each of the bonds to a Mossbauer atom, i.e., partial isomer shifts.5 Partly in order to elucidate structural information, but mainly in an effort to study the bonding properties involving the iron atom, Mossbauer studies of the iron carbonyls and their more complex derivatives have been undertaken.6–8 In these compounds, the iron atoms have coordination number six and oxidation number of zero.
The influence of alloying elements on oxygen diffusion and flexure in tantalum base alloys

Abstract Experiments were conducted in which the flexure of specimens of tantalum and tantalum base alloys exposed on one side to oxygen at low pressures was examined with regard to oxygen diffusion and oxygen solution effects. Diffusion coefficients for oxygen in Ta, Ta-10% W. and Ta-10% W-2.5% Hf (T-222) were calculated from the flexure measurements on the basis of simple strain-diffusion models. The results indicated that both tungsten and hafnium influence oxygen diffusion in tantalum and that for the case of the hafnium-containing alloy, a model with hafnium serving as a saturable trap for oxygen is consistent with the observations.
Serum high density lipoprotein in diabetic patients

The purpose of the present investigation was the study of HDL lipoprotein changes in patients with diabetes mellitus. The comparison was made between 40 normal and 109 diabetic subjects and the following data was obtained: relative HDL concentration (polyacrylamide gel electrophoresis), HDL-cholesterol and apolipoprotein A concentrations. We found significant decreases in HDL (18–28%) and HDL-cholesterol (31–40 mg/ 100 ml) in most diabetics except in those with normalized serum levels of glucose and lipids (34% and 50 mg/100 ml respectively). There was a statistically significant difference in HDL and HDL-cholesterol concentrations between patients in the latter group and other diabetic patients. There was a negative correlation between HDL and HDL-cholesterol and serum glucose levels. No statistically significant difference was found when apolipoprotein A was compared in normal and diabetic subjects. Our results suggest that a deficient binding of cholesterol to apoprotein A might be present in diabetes.
STRUCTURE AND PHYCOBILIPROTEIN COMPOSITION OF PHYCOBILISOMES FROM GRIFFITHSIA PACIFICA (RHODOPHYCEAE)1

Phycobilisomes in Griffithsia pacifica are closely spaced on the thylakoid membrane. By negative staining, attached and isolated phycobilisomes have been shown to have a block shaped appearance. They are 63 nm long, 38 nm high, and 38 nm wide, making them the largest thus far reported. Isolated phycobilisomes, shown to be functionally intact by their 675 nm fluorescence emission (excitation 545 nm) were stable for more than a day. Phycobiliproteins from dissociated phycobilisomes, separated on sucrose gradients and by polyacrylamide electrophoresis, yielded large (R-) and small (r-) molecular weight species of phycoerythrin (ca. 4:1 respectively) constituting 89% of the phycobiliprotein content, with R-phycocyanin 8%, and allophycocyanin 3% accounting for the rest. Phycobilisomes of Griffithsia pacifica and Porphyridium purpureum (Bory) Drew and Ross (P. cruentum) are structurally very similar with phycoerythrin being on the outside and surrounding a core of R-phycocyanin and allophycocyanin.
Exploring the use of electrochemical impedance spectroscopy (EIS) in microbial fuel cell studies

Electrochemical impedance spectroscopy (EIS) is a powerful nondestructive technique that can act as a beneficial addition to the current techniques for studying microbial fuel cells (MFCs). Its application in MFC research should be further explored in the analysis of the internal resistance of MFCs, electrode materials, catalyst coatings on electrodes, biofilm development and electrochemical reactions on the anodes and the cathodes of MFCs.
On the expressive power of query languages for relational databases

The query languages used in relational database systems are a special class of programming languages. The majority, based on first-order logic, lend themselves to analysis using formal methods. First, we provide a definition of relational query languages and their expressive power. We prove some general results and show that only a proper subset of first-order logic formulas may be used as a practical query language. We characterize this subset in both semantic and syntactic terms. We then analyze the expressive power of several real query languages, including languages based on the relational calculus, languages with set operators and aggregate functions, and procedural query languages.Since the partial ordering "is more expressive than" determines a lattice among relational query languages, the results of the paper may be viewed as determining some of the structure of this lattice. We conclude with some applications of the results to the optimization problem for query processing.
Long-term neurologic outcome in psychogenic water drinkers with severe symptomatic hyponatremia: The effect of rapid correction

Abstract purpose: The purpose of our study was to ascertain the safety of rapidly correcting acute symptomatic hyponatremia in psychogenic water drinkers, particularly in regard to any delayed adverse neurologic sequelae. patients and methods: We reviewed the medical records of all known psychogenic water drinkers (34) in our hospital from 1977 to 1989. Using seizure as a marker of severity, we identified 13 patients having a total of 27 episodes associated with severe hyponatremia. We evaluated the charts of those patients in detail to assess the mode of treatment, rate of correction, and long-term neurologic outcome. None of the patients experienced respiratory arrest before treatment, which was initiated within 2 hours of seizure. results: For all 27 episodes, the initial serum sodium level (mean ± SE) was 110.9 ± 1.2 mmol/L, and the rate of correction (mean ± SE) was 1.65 ± 0.2 mmol/L/hour. All but one episode were corrected "rapidly" (initial correction rate of 0.7 or more mmol/L/hour) to 120 to 130 mmol/L within 12 hours. The absolute change in the serum sodium level was 15.1 ± 1.2 mmol/L in 12 hours, 21.6 ± 1.4 mmol/L in 24 hours, and 25.9 ± 1.4 mmol/L in 48 hours. In no instance did therapy induce hypernatremia. All patients recovered immediately after treatment. There was no clinical or radiologic evidence of adverse neurologic sequelae immediately after treatment or after 6 years of follow-up. conclusion: In this series of male psychogenic water drinkers, early "rapid" correction of acute symptomatic hyponatremia by raising the serum sodium level 15 mmol/L in 12 hours while maintaining an absolute change in the serum sodium level of 26 mmol/L within 48 hours produced no long-term neurologic sequelae.
Sequences of islet amyloid polypeptide precursors of an Old World monkey, the pig-tailed macaque (Macaca nemestrina), and the dog (Canis familiaris).

The 37-amino acid islet amyloid polypeptide represents the major protein component present in islet amyloid deposits. Although the presence of islet amyloid is a characteristic pathological feature of the islets of humans, monkeys and cats with Type 2 (non-insulin-dependent) diabetes mellitus, it is not found in the islets of diabetic rats, mice or dogs. To further explore the molecular basis for these species differences in amyloid deposition we have used a polymerase chain reaction based method to clone cDNAs encoding the monkey (Macaca nemestrina) and dog (Canis familiaris) islet amyloid polypeptide precursors. The predicted amino acid sequence of the monkey precursor is 96% identical to that of the human protein; differences include one replacement in the signal peptide and three in the islet amyloid polypeptide domain. The sequence of the dog precursor is most closely related to that of the cat protein (85% identity); the sequences of dog and cat islet amyloid polypeptide differ only at two positions and are identical in the region of amino acids 20–29, the region thought to be primarily responsible for amyloidogenesis. Thus, amino acid residues in addition to those at positions 20–29 may facilitate the aggregation of islet amyloid polypeptide. The presence of amyloid deposits in some dog pancreatic endocrine tumours suggests that the dog protein can be amyloidogenic, perhaps due to elevated expression of islet amyloid polypeptide by the tumours relative to normal islets.
Pyroelectricity of Water Ice

Water ice usually is thought to have zero pyroelectricity by symmetry. However, biasing it with ions breaks the symmetry because of the induced partial dipole alignment. This unmasks a large pyroelectricity. Ions were soft-landed upon 1 mum films of water ice at temperatures greater than 160 K. When cooled below 140-150 K, the dipole alignment locks in. Work function measurements of these films then show high and reversible pyroelectric activity from 30 to 150 K. For an initial approximately 10 V induced by the deposited ions at 160 K, the observed bias below 150 K varies approximately as 10 Vx(T/150 K)2. This implies that water has pyroelectric coefficients as large as that of many commercial pyroelectrics, such as lead zirconate titanate (PZT). The pyroelectricity of water ice, not previously reported, is in reasonable agreement with that predicted using harmonic analysis of a model system of SPC ice. The pyroelectricity is observed in crystalline and compact amorphous ice, deuterated or not. This implies that for water ice between 0 and 150 K (such as astrophysical ices), temperature changes can induce strong electric fields (approximately 10 MV/m) that can influence their chemistry, ion trajectories, or binding.
PHORADENDRON FLAVESCENS: CHROMOSOMES, SEEDLINGS, AND HOSTS

REASONS FOR this study were two: to investigate the possibility that different chromosome races of Phoradendron flavescens (Pursh) Nutt. might occur selectively on certain hosts and to determine whether the unusual sex-chromosome mechanism reported by Billings (1932, 1933) for P. flavescens var. macrophyllum Engelm. and for P. villosum Nutt. might operate in the plants of P. flavescens available in Virginia. Phoradendron Nutt. is a genus of 240 species widespread in the New World (Trelease, 1916). All members of the genus are semi-parasitic, mostly on woody angiosperms, though some are on conifers. Flowers are unisexual. All representatives of Phoradendron within the United States are reputedly dioecious, but many tropical species often have both sexes in the same spike. Phoradendron flavescens is dioecious. The species is polymorphic and occurs on a series of woody dicotyledonous hosts. Geographic range of the species is "from southern New Jersey to the lower Wabash, Oklahoma and eastern Texas, reaching southeast to the gulf and the ocean" (Trelease, 1916) and is likewise in New Mexico on cultivated Fraxinus (Tidestrom and Kittell, 1941). Additional species are in Florida, Texas, and New Mexico; otherwise, only P. flavescens is considered to be throughout the area designated-with var. orbiculatum Engelm. in Arkansas, Oklahoma, and Louisiana. Trelease, whom we choose to follow, considered that P. flavescens var. macrophyllum was properly a synonym under P. macrophyllum (Engelm.) Cockerell. Curtiss (1878) wrote that P. flavescens "abounds in Florida, where it may be found on nearly every kind of tree" and occasionally parasitic upon itself. Harper (1928) listed 30 species in 19 genera as hosts, for this mistletoe in Alabama and, by letter of ,,October 27, 1948, reported Ilamamelis as an additional host. Deam (1940) named 7 species in 6 genera as common hosts in Indiana for this hemiparasite. Bayard Long (letter of November 2, 1948) and Edgar T. Wherry (letter of October 20, 1948) stated that in the New Jersey-Pennsylvania part of its range this mistletoe is commonly on Nyssa sylvatica, rarely on Acer rubrum, and never on other hosts. Reed and Reed (1951) recorded for Kentucky 24 host species in 19 genera. Hedgcock (1915) enumerated for P. flavescens throughout its range 62 hosts in 33 genera, but he interpreted the species in a more inclusive sense than Trelease did in his monograph. METHOD)S.-For chromosome analyses young leaves and actively growing stem-tips of P. fla-
Quantitative analysis of lycopene isomers in human plasma using high-performance liquid chromatography-tandem mass spectrometry.

An analytical method for the determination of the concentrations of total lycopene and its cis and all-trans isomers in human plasma has been developed using high-performance liquid chromatography−tandem mass spectrometry (LC−MS−MS). This method was based on the observation that, during negative ion atmospheric pressure chemical ionization with collision-induced dissociation, a unique fragment of m/z 467 was formed from the molecular ion of m/z 536 by elimination of a terminal isoprene group. The use of multiple reaction monitoring facilitated the selective detection of lycopene isomers and an internal standard without interference from the isobaric carotenoids α-carotene and β-carotene, which are also abundant in human plasma. Measurement of total lycopene was carried out using a C18 high-performance liquid chromatography (HPLC) column and an isocratic mobile phase consisting of acetonitrile/methyl tert-butyl ether (95:5) so that all lycopene isomers eluted as a single chromatographic peak. all-trans-Lyc...
SURGERY FOR OBESITY

The medical risks of obesity increase exponentially as weight increases, and these risks are reduced by sustained weight loss. Behavior modification and dieting provide an approximately 6% loss of body weight at 1 year. Fenfluramine provides an approximately 8% weight loss at 1 year, which can be doubled to 16% when a drug such as phentermine, which works through a different biochemical mechanism, is added to it. This amount of weight loss is insufficient for many severely obese individuals. It was with these facts in mind that the National Institutes of Health Consensus Conference in 1992 recommended that obesity surgery is an appropriate treatment for patients with a body mass index greater than 40 kg/m2 who had failed in attempts at medical treatment and for patients with a body mass index greater than 35 kg/m2 with severe complications of obesity. Vertically banded gastroplasty and Roux-en-Y gastric bypass are the two operations presently recommended because of their relative safety and effectiveness. This article reviews previous procedures that have provided insight into the mechanisms by which these surgeries cause weight loss. The presently used surgeries and their results also are reviewed because until medical therapy improves substantially, surgery remains the most reasonable treatment option for most morbidly obese patients.
Sequential location of two facilities: comparing random to optimal location of the first facility

We investigate sequential location of two facilities. One strategy is to locate the first facility at its single facility optimum. A second strategy is to randomly locate the first facility. The second facility is then located at its optimal location given the first facility’s location. We investigate which of these two strategies is better. Three objectives are tested: minisum, minimax, and competitive. We considered three environments: uniform demand in a square, discrete demand in the plane, and demand at nodes of a network. For the competitive objective we obtained what might be considered the expected result of locating the first facility optimally is better. For the minisum and minimax objectives, we found a surprising result: it is better to locate the first facility at random. We investigate the reasons behind these results which support the principle of add-heuristics and the greedy randomized adaptive search procedure where the search does not necessarily select the best solution in a greedy sequential approach.
A tiered approach to threshold of regulation

This paper presents methods for extending the principle of a single "threshold of regulation" to a range of dietary concentrations between 0.5 and 15 parts per billion by using structure-activity relationships, genotoxicity, and short-term toxicity data. The database used to develop the FDA's threshold of regulation was examined to determine whether structural parameters or the result of certain short-term toxicity tests could be used to define a subset of less potent substances that supports higher threshold levels. In addition, results of reproductive toxicity tests for 3306 compounds and other multidose toxicity tests for 2542 compounds were compared with the database of carcinogenic potencies to establish that carcinogenic endpoints are the most conservative toxicity endpoint for establishing thresholds of regulation.
Climate informed monthly streamflow forecasts for the Brazilian hydropower network using a periodic ridge regression model

Summary Streamflow simulation and forecasts have been widely used in water resources management, particularly for flood and drought analysis and for the determination of optimal operational rules for reservoir systems used for water supply and energy production. Here we include climate information in a periodic-auto-regressive model in order to provide monthly streamflow forecasts for 54 hydropower sites in Brazil. Large scale climate information is included in the model through the use of climate indices obtained from the sea surface temperature field of the tropical Pacific and sub-tropical Atlantic oceans and the low-level zonal wind field over southeast Brazil. Correlation analysis of climate predictors and streamflow data show that the dependence of the latter on climate variability is seasonal and also a function of the lead time of the forecasts. A ridge regression framework is adopted in order to shrink parameter estimates and improve model outputs. The proposed model is compared with an ordinary linear regression based model with predictors selected by the BIC criterion and with the classical linear periodic-auto-regressive model (PAR), where no climate information is used. Cross-validated results show that the inclusion of climate indexes is able to improve forecast skills up to 3 months lead time. Higher skills are observed for reservoirs with large catchment areas.