cssi/SciSciGPT-SciSciNet huggingface dataset:
Methylmercury decomposition in sediments and bacterial cultures: involvement of methanogens and sulfate reducers in oxidative demethylation.

Demethylation of monomethylmercury in freshwater and estuarine sediments and in bacterial cultures was investigated with 14CH3HgI. Under anaerobiosis, results with inhibitors indicated partial involvement of both sulfate reducers and methanogens, the former dominating estuarine sediments, while both were active in freshwaters. Aerobes were the most significant demethylators in estuarine sediments, but were unimportant in freshwater sediments. Products of anaerobic demethylation were mainly 14CO2 as well as lesser amounts of 14CH4. Acetogenic activity resulted in fixation of some 14CO2 produced from 14CH3HgI into acetate. Aerobic demethylation in estuarine sediments produced only 14CH4, while aerobic demethylation in freshwater sediments produced small amounts of both 14CH4 and 14CO2. Two species of Desulfovibrio produced only traces of 14CH4 from 14CH3HgI, while a culture of a methylotrophic methanogen formed traces of 14CO2 and 14CH4 when grown on trimethylamine in the presence of the 14CH3HgI. These results indicate that both aerobes and anaerobes demethylate mercury in sediments, but that either group may dominate in a particular sediment type. Aerobic demethylation in the estuarine sediments appeared to proceed by the previously characterized organomercurial-lyase pathway, because methane was the sole product. However, aerobic demethylation in freshwater sediments as well as anaerobic demethylation in all sediments studied produced primarily carbon dioxide. This indicates the presence of an oxidative pathway, possibly one in which methylmercury serves as an analog of one-carbon substrates.
Kolbenverdichter für ölfreie Förderung von Luft und Gasen

Der im folgenden beschriebene Kolbenverdichter arbeitet mit ungeschmierten Kolben und Stopfbuchsen. Die Abdichtung wird durch Labyrinthdichtungen erreicht. Dadurch behalt das verdichtete Medium die ursprungliche Reinheit, so das der Verdichter in der chemischen Industrie und der Lebensmittelindustrie da verwendet werden kann, wo vollig reine Druckluft gebraucht wird.
Temperature-Dependent $I$ – $V$ Characteristics of a Vertical $\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}$ Tunnel FET

We report on the experimental temperature-dependent characteristics of vertical In0.53Ga0.47As tunnel field-effect transistors (TFETs) at low drain bias to provide key insight into its device operation and design. Leakage floor (IOFF) is determined by the ungated p+-i-n+ reverse bias leakage and is dominated by Shockley-Read-Hall generation-recombination current. The temperature dependence of subthreshold slope arises from tunneling into mid-gap states at the oxide-semiconductor interface, followed by thermal emission into the conduction band. At intermediate gate voltages, pure band-to-band tunneling dominates, while at higher gate voltages, current transport is diffusion limited. The temperature-dependent study of In0.53Ga0.47As TFET highlights the importance of passivating the III-V and dielectric interface.
Blown Cellulose Fiber Thermal Insulations: Part 2—Thermal Resistance

The thermal resistance of a number of commercial blown loose-fill cellulose fiber thermal insulations measured using the guarded hot plate and heat flowmeter methods, is noted. An equation describing the variation of thermal resistance with temperature, temperature difference, density, and thickness derived from these measurements and, with lesser precision, from the data provided by other investigators is given. The equation does not include the effects of chemical content, moisture content, chemical composition, or structure of the paper particles. The thermal resistance of a layer of insulation was found not to be directly proportional to thickness. The equation for thermal resistance fits the National Research Council of Canada (NRC) data with a standard deviation of less than 3.5% for thickness of 50 to 305 mm.
The electron/electron acoustic instability

The electron acoustic wave becomes a normal mode of an unmagnetized collisionless plasma in the presence of two electron components with similar densities, but strongly disparate temperatures. The characteristic frequency of this mode is the plasma frequency of the cooler electron component. If these two electron components have a relative drift speed several times the thermal speed of the cooler component, the electron/electron acoustic instability may arise. This paper describes the parametric dependences of the threshold drift speed and maximum growth rate of this instability, and compares these with the same properties of the electron/ion acoustic instability. Under the condition of zero current, the electron/ion acoustic instability typically has the lower threshold drift speed, so that observation of the electron/electron acoustic instability is a strong indication of the presence of an electrical current in the plasma.
Prostaglandin B2-Induced Cutaneous Vasoconstriction of the Canine Hind Paw

The cutaneous vascular effects of prostaglandin B2 (PGB2) were studied in dogs during constant-flow perfusion of the hind paw. The effects of PGB2 (50-800 ng/kg min-1, ia) on systemic pressure, hind-paw perfusion pressure, and responses to local heating at 45°C (30 seconds) and cooling at 4°C (90 seconds) were measured in 44 dogs. PGB2 increased perfusion pressure by 50 ± 19 mm Hg to 218 ± 21 mm Hg without any effect on systemic arterial blood pressure. The pressor response to cooling increased from 34 mm Hg to 53 mm Hg (50 ng/kg min-1PGB2), but the dilator response to heating was reduced significantly during infusions of PGB2 (50 and 100 ng/kg). Acute denervation and reserpine treatment (0.5 mg/kg dog-1 for 2 days) reduced the constrictor responses to PGB2. The abilities of PGB2 to produce intense vasoconstriction, which is blocked by acute denervation and reserpine, to enhance responses to cooling, and to antagonize responses to heating make this preparation a useful model for the study of Raynaud's phenomenon and suggest that a prostaglandin, perhaps PGB2ss, may participate in cutaneous vasospastic disorders.
Brownian Dynamics Study of Mixed Linear-Hyperbranched Polymers

Brownian dynamics simulations have been performed on a variety of mixed linear-branched molecules. The rheological properties of three different constant molecular weight systems, with varying ratios of linear segments to branch points, are reported. The transition from perfectly branched behavior (low viscosity) to linear-chain-like behavior (high viscosity) is found to occur at a mole fraction of linear segments of 0.8.
Ultra-fine polyelectrolyte hydrogel fibres from poly(acrylic acid)/poly(vinyl alcohol)

Ultra-fine fibrous membranes were prepared by electrospinning of aqueous mixtures of poly(acrylic acid) and poly(vinyl alcohol) at 17%–83% PAA or 0.14–3.5 COOH/OH molar ratios and cross-linked by heat-induced (140 °C, 5 min) esterification. The fibre diameters increased from 270 to 450 nm with increasing PAA contents. The swelling ratio of the fibrous hydrogels increased up to 31 times their dry weight with increasing pH from 2 to 7, and most significantly between pH 4 and pH 5. The liquid uptake of the fibrous hydrogels was attributed to both the liquid diffused into the fibres and that held in the inter-fibre pores. About 53%, 35%, 43% and 37% of the swelling was contributed by the liquid in the inter-fibre pores when the fibrous hydrogels were swollen at pH 2, 4, 5 and 7, respectively. The fully swollen fibrous membranes could be triggered by an applied electric field to swell further. Such additional swelling was dependent upon the polymer compositions, strength of electric field and pH, and was reversible.
Implications for the United States

(1991). Implications for the United States. Arms Control: Vol. 12, European Security without the Soviet Union, pp. 139-144.
The dual function steroid receptor coactivator/ubiquitin protein-ligase integrator E6-AP is overexpressed in mouse mammary tumorigenesis

Steroid receptor coactivator and corepressor proteins are important mediators of steroid receptor function. Changes in the expression or activity of these limiting cofactors can contribute to the etiology of steroidal cancers. Using a mouse mammary model of multistage tumorigenesis we have examined whether the expression of select steroid receptor coactivators is altered. The 10 kb transcript of the novel dual function steroid receptor coactivator/ubiquitin protein-ligase integrator E6-AP is overexpressed 2.5-4.5 fold in the mammary tumors but not in the precursor steps of tumorigenesis; that is, immortal ductal and alveolar hyperplastic outgrowths. The over expression is striking because the 10 kb transcript is expressed to variable levels in other wild type tissues like the uterus, ovary, testis, kidney and brain but is undetectable in normal virgin mammary gland and the prostate gland. The E6-AP overexpression in the mammary tumors is substantiated by western blot analysis and immunohistochemical analysis. Absence of ER and PR in these tumors in the presence of high levels of E6-AP could contribute to steroid receptor-independent function and tumorigenesis. There is no obvious correlation between p53 (a well-characterized substrate of E6-AP) status (wt vs. mutant) and levels of E6-AP in the mouse mammary tumors.
Numerical computation of metal oxidation problems on bounded domains

This paper is a study of metal oxidation problems with moving oxidation fronts, modeled by Fickian oxygen diffusion through the oxide scale and metal. A numerical algorithm is developed and implemented based on a variable grid finite difference scheme. A domain transformation technique is introduced for the space and time variables, resulting in a transformed problem defined over a fixed domain but with non-linear diffusion equations. The numerical algorithm is implemented for nominal values of the material constants corresponding to titanium alloys at elevated temperatures. Three different benchmark problems with planar, cylindrical and spherical oxidation fronts are analyzed in this work. Also, the influence of the geometry of bounded domains on moving oxidation fronts is discussed.
Doing Research that is Useful to Practice a Model and Empirical Exploration

Drawing from literature on knowledge transfer and cognition, we develop a theoretical model for conducting research that is useful to practitioners. We explore the potential of this model by examin...
Adrenergic modulation of potassium metabolism in uremia

Adrenergic modulation of potassium metabolism in uremia. The effect of chronic beta adrenergic blockade on potassium homeostasis during moderate intensity exercise (40% of VO 2 max) was examined in seven end-stage renal patients who were being maintained on chronic dialysis treatment. Subjects participated in three study protocols: 1) exercise alone, 2) exercise plus propranolol (a nonselective beta-1, beta-2 antagonist), and 3) exercise plus metoprolol (a specific beta-1 antagonist). The basal potassium concentration was similar in all three studies and averaged 4.95 ± 0.12 mEq/liter. During Study 1 (exercise alone), plasma potassium rose by 0.26 ± 0.09 mEq/liter. During exercise with propranolol, plasma K concentration rose significantly higher (Δ plasma K=0.44 ± 0.26 mEq/liter; P
Development of a salt marsh microecosystem

Four replicate outdoor microecosystems were constructed, utilizing “ sodded” Spartina alterniflora salt marsh plots (with attendant fauna and flora) contained within polyvinylchloride (PVC) metabolism chambers which were open to the atmosphere. This study was designed to demonstrate replicability of salt marsh microecosystem units and to observe how closely the structural and functional processes within the microecosystems “tracked” those of the natural marsh site. This paper describes an approach to the design of the units and provides a rationale for measuring selected community structure and functional processes within the units. Each unit consisted of 6 m2 plots of salt marsh with substrate intact to a depth 18 cm and was provided with a flow‐through sea water system to simulate the following characteristics of the tides at the natural site: (1) sheet flow, (2) real time synchrony with the natural tides, (3) depth of inundation, and (4) duration of inundation. In addition, each unit had flow measureme...
Site characterization for field radionuclide migration studies in Climax granite

Radionuclide migration experiments in fractured granite at the Climax Stock, Nevada Test Site, are needed to compare field and laboratory measured retardation factors to determine whether laboratory studies accurately reflect in situ conditions. Initial field activities have concentrated on hydrological investigations to determine whether the fractures in Climax granite are suitable for migration experiments. A critical question was whether we could isolate a single vertical fracture between two boreholes and establish flow along that fracture from an upper to a lower borehole. Of the ten fractures tested, one fracture would not take water at pressures up to 200 psig for 24 hours. Several fractures were so permeable they accepted water at a rate which exceeded the pumping capacity of the equipment. Other fractures failed to show a connection between the two boreholes. In two fractures, we were able to establish a circulating system with up to 90 percent of the injected water being recovered. Constant pressure injection tests were conducted. Intrinsic permeabilities of 33 and 75 ({mu}m){sup 2} were estimated using a radial nonsteady flow model. These values correspond to effective fracture apertures of 20 and 30 {mu}m respectively. Concurrent with the hydraulic testing activities is a study of themore » Climax ground-water chemistry. Our analyses show the natural water to be very different in composition from the granite equilibrated water used in laboratory sorption studies. This paper includes the results of the hydrogeological and geochemical investigations, and describes the overall experimental design plans for the radionuclide migration experiments.« less
The Differences in Electroencephalographic Changes in Patients Undergoing Carotid Endarterectomies while under Local versus General Anesthesia

Objective This study compared the electroencephalographic (EEG) changes occurring during carotid occlusion in 225 consecutive patients undergoing carotid endarterectomies performed by two surgeons, one using local and the other using general anesthesia. Methods A retrospective review of patients undergoing carotid endarterectomies for carotid occlusive disease was conducted. EEG changes associated with intraoperative ischemia (decreased amplitude, generalized slowing, and loss of fast activity) resulting in the need for an indwelling arterial shunt were recorded for the two anesthesia groups. To determine the similarities or differences between the two groups, the groups were compared regarding age, risk factors, and indications for surgery. Results Significant EEG changes were noted in 6 of 96 patients (6.3%) in the local anesthesia group versus 19 of 121 patients (15.7%) in the general anesthesia group. EEG changes consisted solely of generalized slowing in the local anesthesia group, whereas a more varied spectrum was observed in the general anesthesia group. The two groups were similar regarding age and risk factors. Although the local anesthesia group had more asymptomatic patients, symptomatic patients did not have a greater incidence of EEG changes. Conclusion There is a large difference in EEG changes potentially requiring shunt placement in patients undergoing surgery while under local (6.3%) versus general (15.7%) anesthesia. This could not be explained based on age, risk factors, interpretation of EEG findings, or indications between the two groups. We conclude that EEG monitoring may be insensitive and may fail to detect ischemia in patients who are under regional anesthesia. Alternately, the presence of general anesthetics may alter the character of the EEG findings and increase the sensitivity of EEG monitoring to ischemic events.
Impact of radiosurgery on the surgical treatment of trigeminal neuralgia.

Abstract Background The history of the development of current available techniques to treat TN was reviewed. Methods The largest peer-reviewed publications on the surgical treatment of refractory TN were analyzed, considering the pros and cons of each technique. Results of modern peer-reviewed radiosurgery series were presented, taking into consideration the approach of each research article. Radiation doses and targets for radiosurgery were discussed to maximize the understanding of this technique. Results It is concluded that radiosurgery is the least invasive modality with the fewest side effects, although, to match the results of the competing techniques, a substantial number of patients still need some medication intake. Conclusion Further studies determining the ideal target and radiation dose may bring radiosurgery results to the level of the ones achieved with microvascular decompression, currently considered the gold-standard method.
Challenges in marine, soft-sediment benthoscape ecology

In this paper I address three sets of challenges that face ecologists who are studying soft-sediment benthic landscapes (or benthoscapes). These include (a) development of technology and analytical approaches for sea floor mapping and quantifying benthoscape structure, (b) development of benthoscape ecology theory that integrates ideas from terrestrial and other marine systems, but focuses on the unique aspects of these environments, and (c) making empirical headway. Coordinated efforts in all three areas are needed to make progress in understanding soft-sediment systems, which arguably comprise the largest set of landscapes on the earth. In particular, much more work is needed in relating biotic patterns to the actual spatial structural aspects of soft-sediment benthoscapes.
Cancer Survivorship: Developing Clinical Practice Guidelines

Cancer survivorship is a growing field, and advanced practitioners in both oncology and primary care will likely see an increasing number of cancer survivors in their practices. Despite the numerous recent publications and conferences on survivorship, the specific plan of care for cancer survivors remains unclear; this is especially true in the long-term survivorship phase. Advanced practitioners rely on clinical practice guidelines to provide a stan- dard of care for managing various illnesses. This article describes a step-by- step process for developing a practice guideline for cancer survivors based on a national model of care. An example of the guideline is included. J Adv Pract Oncol 2010;1:273-278
Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia in First Complete Remission: Are We Closer to Knowing Who Needs It?

Acute myeloid leukemia (AML) is a very heterogeneous disease. Prognosis is related not only to intrinsic characteristics such as cytogenetics and molecular markers, but also the patient's ability to tolerate therapy, and treatment response. Allogeneic stem cell transplantation (allo-HCT) has been traditionally indicated for poor-risk disease in first complete remission (CR1) or for treatment of relapsed or refractory AML. 'Poor-risk' disease is now better defined due to genetic subtyping, particularly in chromosomally normal AML. In addition, the presence of comorbid conditions should be included in the decision-making process. Improvements in supportive care and the use of modern conditioning regimens have been associated with improved outcomes, mostly due to a reduction in treatment-related mortality. Therefore, a significant proportion of patients with AML-CR1 can potentially benefit from allo-HCT. We give general guidelines on how to incorporate cytogenetic and molecular risk factors, donor selection, and patient characteristics in order to determine when allo-HCT should be indicated in CR1.
Production and purification of a granular-starch-binding domain of glucoamylase 1 from Aspergillus niger

A domain of glucoamylase 1 from Aspergillus niger which binds to granular starch was produced by proteolytic digestion and purified to apparent homogeneity by extraction with corn starch followed by anion-exchange chromatography and gel filtration. The peptide has a molecular weight of 25,100, contains approximately 38% carbohydrate (w/w) and corresponds to residues 471-616 at the C-terminus of glucoamylase 1. The peptide bound to granular corn starch maximally at 1.08 nmol/mg starch. It inhibited the hydrolysis of granular starch by glucoamylase 1 but had no effect on the hydrolysis of starch in solution.
Rotation of the linear-polarization plane of transmitted and reflected light by single- and few-layer graphene

Transmission and reflection measurements performed on single- and few-layer graphene indicate the presence of circular dichroism (CD). Surface roughness appears to moderate the effect with ultraflat graphene on mica not showing CD. Application of an external magnetic field had no effect, ruling out any contribution from spin polarization. Symmetry breaking of the graphene lattice due to a soft shear mode in the graphene sheet is believed to be the origin of the requisite asymmetry for this effect to occur.
The Politics of Ground‐Water Management Reform in Oklahomaa

This paper examines the politics of ground-water management reform in Oklahoma. It argues that the geographic distribution of water supplies and uses significantly modifies the distribution of costs and benefits of reform among political constituencies. Effective restrictions on ground-water withdrawals would raise large and immediate threats to irrigators and farm communities dependent on irrigation in western Oklahoma. Municipal and industrial water users, concentrated in eastern Oklahoma and reliant on more plentiful surface-water supplies, would receive more diffuse, longer-range benefits to management reform. These effects have significant implications for the politics of ground-water management. The results of the analysis suggest that approaches taken to ground-water management reform in Oklahoma, and the other eastern Ogallala states, may be more effective and realistic than might initially be thought. Oklahoma's present ground-water law, adopted in 1973, is based on a utilization policy of planned depletion and represents a major change in direction entailing significant implementation costs. Agricultural interests, seeking to protect their irrigation rights, were influential in both the adoption and implementation processes. Considering the problems encountered, the immediate outlook for effective state management of ground water remains unfavorable. Future prospects, however, are more favorable. Oklahoma has developed an institutional structure capable of responding to changing priorities and needs of irrigators. This long-run approach to ground-water management matches the interests of the most relevant political constituency and may prove to be the most effective strategy.
Application of the CO2 Laser to Thermal Properties Measurements in Biomaterials

The CO2 laser provides radiation that is strongly absorbed and only weakly back-scattered by high water-content materials, such as biological tissue. Several methods can be employed to obtain radial distributions of laser irradiance that are described by simple mathematical functions. It is therefore possible to use the CO2 laser to noninvasively establish an accurately known surface heat source. An effective thermal conductivity of the material can be determined from the temperature response due to laser heating. Thermal conductivity is reported for agar gel using CO2 laser heating and thermocouple temperature sensing.
Characterization and potential use of a Cryptosporidium parvum virus (CPV) antigen for detecting C. parvum oocysts.

The purpose of this study was to characterize the viral symbiont (CPV) of Cryptosporidium parvum sporozoites and evaluate the CPV capsid protein (CPV40) as a target for sensitive detection of the parasite. Recombinant CPV40 was produced in Escherichia coli, purified by affinity chromatography, and used to prepare polyclonal rabbit sera specific for the viral capsid protein. Anti-rCPV40 recognized a 40 kDa and a 30 kDa protein in C. parvum oocysts and appeared to localize to the apical end of the parasite. Anti-rCPV40 serum was capable of detecting as few as 1 C. parvum oocyst in a dot blot assay, the sensitivity being at least 1000-fold greater than sera reactive with total native C. parvum oocyst protein or specific for the 41 kDa oocyst surface antigen. Water samples were seeded with C. parvum oocysts and incubated at 4, 20, or 25 °C for greater than 3 months to determine if CPV levels were correlated with oocyst infectivity. Samples were removed monthly and subjected to mouse and cell culture infectivity, as well as PCR analysis for infectivity and viral particle presence. While sporozoite infectivity declined by more than 75% after 1 month at 25 °C, the CPV signal was similar to that of control samples at 4 °C. By 3 months at 20 °C, the C. parvum oocysts were found to be non-infectious, but retained a high CPV signal. This study indicates that CPV is an excellent target for sensitive detection of C. parvum oocysts in water, but may persist for an indefinite time after oocysts become non-infectious.
Nanoindentation of juvenile and mature loblolly pine ( Pinus taeda L.) wood fibers as affected by thermomechanical refining pressure

The effects of thermomechanical refining pressures, varying from 2 to 18 bars, on the cell-wall properties of refined wood fibers of a 54-year-old loblolly pine (Pinus taeda L.) with reference to both juvenile (JW) and mature wood (MW) were investigated using nanoindentation and atomic force microscopy. The results of this study indicate that refining pressure plays a significant role in the physical damage sustained by refined wood fibers. No obvious damage was observed in the cell walls of MW fibers refined at 2 and 4 bar. Nanocracks ( 3,000 nm in width) were found in both MW and JW fibers subjected to a refining pressure of 14 and 18 bar. The micro damage to the fibers refined at higher pressures was more severe inside the lumen than on the surface of the fibers, and the lumen or S3 layer was significantly damaged. The elastic modulus, hardness, and creep resistance of MW fibers were higher than those of the JW fibers subjected to the same refining-pressure conditions. The elastic modulus and hardness decreased, whereas nanoindentation creep increased, with increasing refining pressure. This study also suggests that lower refining pressures ( 14 bar for MW and >12 bar for JW) should be avoided in the manufacture of fiberboards and wood fiber–polymer composites, because of the lower aspect ratio of the fiber bundles, shorter length of the fibers and fines, and severe damages to the fiber cell walls.
A revised potential-energy surface for molecular mechanics studies of carbohydrates.

Abstract A revised CHARMM-type molecular mechanics potential-energy function has been developed for use in the dynamical simulation of simple carbohydrates in aqueous solution. Atomic charges used in this parameterization were taken to be those previously determined to be appropriate for hydrogen-bonded systems, and the various force-constants were selected by the nonlinear least-squares matching of the calculated normal-mode frequencies and minimum-energy structure to experiment as a function of the parameter set. The new function was found to represent the vibrational spectrum and ring pucker of α- d -glucopyranose as well as previously studied potentials, while incorporating the charges necessary for the simulation of condensed phases. Molecular dynamics simulations of the motions of α- d -glucopyranose in vacuo in both the 1 C 4 and 4 C 1 conformation were conducted, and compared to the results of previous simulations using another potential-energy function. The revised potential function was found to produce a d -glucose molecule less flexible in vacuo than had been previously observed.
Modified production switching heuristics for aggregate production planning

Abstract The Production Switching Heuristic (PSH) developed by Mellichamp and Love [ Management Science 24 , 1242–1251] has been suggested as a more realistic, practical and intuitively appealing approach to aggregate production planning (APP). In this paper, the PSH has been modified to present a more sophisticated open grid search procedure for solving the APP problem. The effectiveness of this approach has been demonstrated by determining a near-optimal solution to the classic paint factory problem using a personal computer based application written in THINK PASCAL. The performance of the modified production switching heuristics is then compared in the context of the paint factory problem with results obtained by other prominent APP models including the linear decision rule, parametric production planning, and PSH to conclude that the modified PSH offers a better minimum cost solution than the original PSH model.
On the Rational Description of Mixtures

The rational activity of a solute becomes equal to the mole fraction of the solute as the mixture becomes infinitely dilute. Simultaneously, the corresponding rational activity coefficient approaches unity. A rational description of a mixture is such that the activity coefficient of each solute component is rational. It is shown for a binary mixture that a description is rational if and only if the solvent osmotic coefficient approaches unity as the solvent mole fraction approaches unity. When the description is not rational, the limiting value of the osmotic coefficient is the van't Hoff number. For multicomponent mixtures, the limiting behavior of the osmotic coefficient is related to the composite extent of association and/or dissociation of all the solutes. It is further shown how the extent of aggregation of individual solutes at infinite dilution can be determined from the limiting behavior of individual activity coefficients. Die rationelle Aktivitat eines gelosten Stoffes wird, im Falle unendlicher Verdunnung, gleich seinem Molenbruch. Gleichzeitig nahert sich der Wert des rationellen Aktivitatskoeffizienten dem Wert eins. Eine rationelle Beschreibung einer Mischung besteht darin, das fur jede geloste Komponente der Aktivitatskoeffizient rationell ist. Fur eine binare Mischung wird gezeigt, das die Beschreibung dann und nur dann rationell ist, wenn der osmotische Koeffizient des Losungsmittels bei Naherung dessen Molenbruchs an eins sich dem Wert eins nahert. Bei nicht rationeller Beschreibung nimmt der osmotische Koeffizient die van't Hoff-Zahl als Grenzwert an. Fur multikomponente Mischungen hangt das Grenzverhalten des osmotischen Koeffizienten von dem Ausmas der Assoziation und/oder der Dissoziation aller gelosten Stoffe ab. Es wird weiterhin gezeigt, wie das Mas der Aggregation der einzelnen gelosten Stoffe bei unendlicher Verdunnung bestimmt werden kann aus dem Grenzverhalten der einzelnen Aktivitatskoeffizienten.
Radio Sources and Star Formation in the Local Universe

Galaxies from the entire Uppsala Galaxy Catalog (UGC) have been identified with 4583 radio sources stronger than 2.5 mJy at 1.4 GHz from the NRAO VLA Sky Survey (NVSS). The complete sample of 3398 galaxies brighter than mp = 14.5 in the area defined by δ > -2°30' and |b| > 20° yielded the UGC/NVSS sample of 1966 radio sources. Their dominant energy sources were classified as stars (85%) or active galactic nuclei (15%). The luminosity function of star-forming galaxies agrees well with the far-infrared (FIR) luminosity function converted to 1.4 GHz by the FIR/radio correlation. The spectral power density of star-forming galaxies is USF = (1.53 ± 0.07) × 1019 W Hz-1 Mpc-3 (statistical errors only) if H0 = 70 km s-1 Mpc-1. We used a model consistent with the observed FIR/radio correlation to estimate the corresponding star formation rate density within the past τ ~ 3 × 108 yr; it is ρSF(M > 0.1 M⊙) ≈ 0.018 M⊙ yr-1 Mpc-3. The radio sources in star-forming galaxies may be evolving even at moderately low redshifts (z ~ 0.1).
Statistics, renewal theory, and particle transport

Abstract A model involving integral renewal equations is derived which describes the ensemble-averaged intensity for time-independent particle transport in a nonscattering medium composed of two randomly mixed, immiscible fluids. It is shown that for a special class of mixing statistics these renewal equations can be recast into integro-differential equations resembling usual transport/kinetic equations. An extension of this model is proposed which includes time dependence as well as scattering. This generalizes an earlier description proposed for the special case of Markov mixing statistics. An Appendix is included which gives several statistical results useful in this line of research.
TUNNELING INTO SUPERCONDUCTORS

The tunneling of electrons through a thin insulating layer between a normal and a superconducting metal is discussed. A previous derivation is examined to bring out the connection with the semiconductor model of a superconductor, and the quasi-particle excitations in normal and superconducting states are discussed. (H.D.R.)
Investigating the effects of filtering, clipping, and power amplification on the performance of OFDM waveforms

Orthogonal Frequency Division Multiplexing (OFDM) has become a very popular technique for digital data transmission on multipath fading channels due to its low computational complexity and simple equalization process. However, the multipath component of these types of channels causes a phenomenon known as frequency selective fading. This type of fading can severely degrade or completely eliminate the signal energy of many of the OFDM tones producing an irreducible error rate, even when no noise is present. Consequently, most OFDM systems operating in multipath fading environments utilize some form of forward error correction (FEC) and block interleaving. OFDM waveforms which utilize FEC are usually referred to as coded OFDM (COFDM). One of the main drawbacks of OFDM and COFDM waveforms is the very large peak envelope power to average power ratio (PAPR) which requires the use of very linear power amplifiers (PA) and a large power back-off into the PA. To reduce the PAPR, clipping is typically utilized. In addition, filtering must be applied to OFDM and COFDM waveforms in order to contain their spectral occupancy. This paper will investigate the effects of filtering, clipping and power amplification on the performance of OFDM and COFDM waveforms. The multipath fading channels used for testing will be based on the High Frequency (HF) channels due to their challenging nature.
Update in rheumatology.

The 1997 literature included important information on new treatment approaches to rheumatoid arthritis, ways to moderate toxic effects of antirheumatic drugs, state-of-the-art laboratory testing, a...
Market Reactions to Merger, Acquisition, and Divestiture Announcements in the Media Industries

There has been extensive restructuring in the media industries in recent times. This article examines the effects of large media restructuring transactions on the value of firms engaging in such transactions. It considers all media restructuring transactions with a value of over $1 billion between 1997 and 2008—a time period that included 1 of the largest waves of mergers and acquisitions (M&A) activity in industrial history, and was marked in media by transformative changes in the industry due to digital technology and the loosening of ownership restrictions under the Telecommunications Act of 1996. Over that time period, 57 M&A transactions with a total value of $675 billion and 65 divestitures with a total value of $338 billion were identified. This article employs event-study methodology to calibrate the impact of these restructurings on firm value. Over time, the market was cautious about the ability of media firms to launch successful mergers or acquisitions, with losses for the media acquirers larger than those in cross-industry studies. This is even more pronounced when the acquirer is a non-media firm. Alternatively, divestitures yield positive results for both buyers and sellers. Recognizing the impact that restructuring has on firms, this work provides insights for understanding the market evaluation of future restructuring transactions. ACCESS TO FULL TEXT
Ab-initio heats of formation of medium-sized hydrocarbons. 4. Perhydrotriquinacene

Abstract The ΔH f of perhydrotriquinacene is obtained from that of adamantane and their enthalpy of isomerization computed by ab initio SCF methods, with corrections for zero-point and thermal effects.
VERTICAL MIGRATION OF A MIXED-SPECIES EUGLENA (EUGLENOPHYTA) ASSEMBLAGE INHABITING THE HIGH-INTERTIDAL SANDS OF NYE BEACH, OREGON(1).

Comparatively little is known about the vertical migration of the microphytobenthic community forming visible patches on high-energy beaches. We collected surface and cored samples to evaluate the timing and extent of downward migration of a multispecies Euglena assemblage inhabiting Nye Beach, Oregon. Euglena density at the surface was highly variable and was not correlated with the time of low tide or instantaneous irradiance measurements; however, triplicate cores collected at low and high tides revealed a tidal rhythm in mean depth. On average, 95% of the assemblage occurred within 1 cm of the surface during low tide, but 54% of the assemblage was collected between 1 and 8 cm below the surface during high tide. A midday shading experiment revealed that short-term changes in irradiance levels altered the Euglena density at the sediment surface by inducing vertical migration. This response to short-term fluctuations in light may explain the weak correlation between cell density at the surface and time of day. The high-intertidal location of these patches prevented the removal of nonmigrating cells by daily high tides, which increased the variability in surface samples and obscured the tidal migration rhythm detected in the core samples. Due in part to the semidiurnal nature of Oregon tides, this study provides in situ confirmation of past mesocosm research indicating that sediment disturbance during daily submersed periods is an important process in maintaining the quasi-tidal rhythm in the appearance and disappearance of Euglena spp. from the surface of beaches and intertidal sandflats.
Decreased pancreatic CCK receptor binding and CCK-stimulated amylase release in Zucker obese rats

Abstract In Zucker obese rats the response to the effects of CCK on food intake and pancreatic exocrine function are decreased. However, it is unknown whether the decreased responsiveness is due to decreased receptor number and/or sensitivity or abnormal circulating concentrations of CCK. In these experiments percent total binding of 125I-CCK-33 to pancreatic acini from obese rats was one-half that in lean rats when data was expressed on a per μg DNA basis (19.6±5.1 vs. 47.4±11.4, p
Erythropoietin receptors induced by dimethyl sulfoxide exhibit positive cooperativity associated with an amplified biologic response.

Abstract Erythropoietin triggers the differentiation of erythrocyte progenitors by binding to receptors on their plasma membrane. We report here that pretreatment of erythropoietin-responsive murine erythroleukemia cells with chemical inducers resulted in a striking increase in erythropoietin-specific hemoglobinization. This amplification of the erythropoietin biologic response was accompanied by the induction of a new population of high-density receptors (approximately 20,000 per cell) exhibiting marked positive cooperativity. Erythropoietin binding to new receptors displayed a convex upward Scatchard plot and a Hill coefficient (nH) of 6.75. Measurement of erythropoietin receptor mRNA demonstrated an initial decrease in receptor transcript followed by an approximately 2- to 3-fold increase after 24-48 hr. This increase in receptor message does not appear to account for the magnitude of the receptor up-regulation by dimethyl sulfoxide. We propose that this positive cooperativity reflects the interaction (clustering) of receptors, presumably through the formation of homooligomers or heterooligomers, and that this receptor interaction may amplify the erythropoietin signal transduction pathway.
On the relationship between queen number and fecundity in polygyne colonies of the fire ant Solenopsis invicta

ABSTRACT. The reproductive status of individual queens in relation to the number of queens in polygyne colonies of Solenopsis invicta Buren was investigated under both field and laboratory conditions. In field colonies, the weight of individual queens is inversely related to the number of resident queens present. The weight of a queen is positively correlated with fecundity, as measured by the number of eggs laid in 5 h in isolation. Thus increasing queen number has a strong negative effect on the fecundity of individual queens in these colonies. A similar relationship was established in standardized laboratory colonies using queens from a single experimental population. Colony size by itself had no significant effect on queen weight in either the field or laboratory colonies, suggesting that the inverse relationship between queen number and fecundity results from mutual inhibition among queens, possibly involving pheromones, rather than reduced nutrition through lower worker/queen ratios. While uninseminated queens can comprise up to 50% of the functional (i.e. egglaying) queens in polygyne colonies of this ant, they tend to be less fecund than their inseminated nestmates; uninseminated queens within a given colony generally weigh 5–25% less.
Assessment of Secondhand Smoke Exposure at School Among U.S. Middle and High School Students

To obtain nationally representative estimates of the prevalence of secondhand smoke (SHS) exposure at U.S. schools, we assessed the prevalence and correlates of SHS exposure at school among U.S. mi...
DNA delivery from an intravascular stent with a denatured collagen-polylactic-polyglycolic acid-controlled release coating: mechanisms of enhanced transfection

We previously demonstrated that DNA–polylactic–polyglycolic acid (PLGA)-coated stents can deliver genes to the arterial wall with reporter expression involving 1% of neointimal cells. The present study investigated a novel formulation utilizing denatured collagen in DNA-stent coatings; denatured collagen was hypothesized to enhance gene transfer due to adhesion molecule interactions and actin-related mechanisms. Arterial smooth muscle cells (SMCs) cultivated on denatured collagen had significantly greater plasmid DNA (β-galactosidase) transfection than SMC grown on native collagen (18.3±1.2 vs 1.0±0.1%, P<0.001). The denatured-collagen effect was completely blocked with anti-αvβ3 integrin antibody. SMCs cultivated on native collagen supplemented with tenascin-C (TN-C), a protein recognized by αvβ3 integrins, showed a 33-fold increase in transfection compared to control (P<0.001); this effect was also blocked with anti-αvβ3 antibody. We observed that cells grown on denatured collagen had marked F-actin-enriched stress fibers and intense perinuclear G actin, compared to those grown on native collagen, which demonstrated F-actin-enriched focal adhesions without perinuclear G-actin localization. Cytochalasin-D, an F actin depolymerizing agent, caused significantly increased SMC transfection in cells cultivated on native collagen compared to control cells (18.0±1.8 vs 3.02±0.9%, P<0.001) further supporting the view that actin-related cytoskeletal changes influence transfection. A denatured-collagen–PLGA composite vascular stent coating similarly resulted in increased plasmid DNA green fluorescent protein (GFP) expression compared to controls (P<0.001) in SMC cultures; the increased transfection was blocked by anti-αvβ3 antibody. Pig coronary studies comparing denatured-collagen–PLGA-coated stents containing plasmid DNA (encoding GFP) to coated stents without DNA demonstrated 10.8% of neointimal cells transfected; this level of expression was almost an order of magnitude greater than previously reported with a DNA delivery stent. It is concluded that denatured collagen incorporated into plasmid DNA-stent coating formulations may increase the level of gene expression in vitro and in vivo because of integrin-related mechanisms and associated changes in the arterial smooth muscle cell actin cytoskeleton.
HIV risk in women: A multifaceted model.

A comprehensive model was designed to predict risky HIV-related sex in women from a set of behavioral interpersonal and psychoattitudinal measures. Survey measures were administered to two university samples of 234 and 263 women. Three sets of dependent measures assessed Partner-Related HIV Risk Unprotected Vaginal Intercourse and Anal Intercourse. There were three multifaceted sets of independent variables that involved 12 factors. The first set behavioral risk involved (a) Social Substance Use (b) Hard Substance Use (c) Foreplay Sexual Experience and (d) Advanced Sexual Experience. The second set interpersonal risk examined (a) Victimization (b) Anticipated Partner Reaction (c) Birth Control Sexual Assertiveness (d) Refusal Sexual Assertiveness and (e) Initiation Sexual Assertiveness. The third set psychoattitudinal risk involved (a) Psychosocial Functioning (b) Psychosexual Attitudes and (c) Self-Efficacy for AIDS Prevention. Substantial variance was explained using structural modeling methods with the strongest prediction involving behavioral and interpersonal HIV risk factors. Psychoattitudinal factors were less central although still important. The results supported and extended previous findings and suggested that the biggest HIV risk factors for women include: greater social substance use greater sexual experience anticipated or actual victimization low assertiveness about requesting birth control overly positive psychosocial attitudes negative attitudes about sexuality and less self-efficacy about avoiding HIV risk. (authors)
Specific entities affecting the craniocervical region: syndromes affecting the craniocervical junction

Introduction The craniocervical junction is a vital component in understanding the function of the human central nervous system. It is the threshold for major pathways affecting both brain and spinal cord function, and these structures are intricately housed in a network of bone, ligaments, and soft tissues. Abnormal development of any of these components may lead to altered structure, and therefore, altered function in the central nervous system.
Ampicillin Prevents Intrapartum Transmission of Group B Streptococcus

Early-onset group B streptococcus (GBS) disease in the infant is acquired by vertical transmission from the mother colonized with GBS. Thirty-four women colonized with GBS were treated with intravenous ampicillin sodium during labor. None of their infants were colonized with GBS at birth or within 48 hours. Twenty-four women colonized with GBS received no antibiotic therapy; 14 (58%) of their infants were colonized with GBS at birth or by 48 hours. This difference was highly significant. Mechanisms by which this may have occurred were temporary suppression of GBS vaginal and rectal colonization, high concentration of ampicillin in the amniotic fluid, and transplacental transport of the antibiotic to the infant. In areas where GBS disease is prevalent, we recommend screening pregnant women (34 to 36 weeks' gestation) and treating those colonized with GBS (with no history of penicillin hypersensitivity) with intravenous ampicillin during labor. ( JAMA 241:1245-1247, 1979)