cssi/SciSciGPT-SciSciNet huggingface dataset:
Comparative Cost-Effectiveness Analysis of Modified 1-Layer versus Formal 2-Layer Vasovasostomy Technique

Purpose: Approximately 2% to 6% of men undergoing vasectomy will ultimately have it reversed. Cost is a major consideration for patients and providers with regard to vasovasostomy. Opportunities for cost savings for vasectomy reversal lie in the reduction of variable costs, namely operative time and materials used. In this study we determine the cost benefits of a modified 1-layer vasovasostomy compared to a formal 2-layer vasovasostomy.Materials and Methods: A retrospective analysis was performed of a single surgeon experience of vasectomy reversals performed from 2010 to 2015. The cohort consisted of men who underwent bilateral vasovasostomy using a formal 2-layer or modified 1-layer technique. The primary end points of the analysis were total operative time; number, cost and type of suture used; and patency/postoperative semen analysis. Bivariate analysis was performed for these continuous variables using the Wilcoxon rank test and the chi-square test was used for categorical variables.Results: Of the ...
Landscape management for sustainable supplies of bioenergy feedstock and enhanced soil quality

Agriculture can simultaneously address global food, feed, fi ber, and energy challenges provided our soil, water, and air resources are not compromised in doing so. As we embark on the 19th Triennial Conference of the International Soil and Tillage Research Organization (ISTRO), I am pleased to proclaim that our members are well poised to lead these endeavors because of our comprehensive understanding of soil, water, agricultural and bio-systems engineering processes. The concept of landscape management, as an approach for integrating multiple bioenergy feedstock sources, including biomass residuals, into current crop production systems, is used as the focal point to show how these ever-increasing global challenges can be met in a sustainable manner. Starting with the 2005 Billion Ton Study (BTS) goals, research and technology transfer activities leading to the 2011 U.S. Department of Energy (DOE) Revised Billion Ton Study (BT2) and development of a residue management tool to guide sustainable crop residue harvest will be reviewed. Multi-location USDA-Agricultural Research Service (ARS) Renewable Energy Assessment Project (REAP) team research and on-going partnerships between public and private sector groups will be shared to show the development of landscape management strategies that can simultaneously address the multiple factors that must be balanced to meet the global challenges. Effective landscape management strategies recognize the importance of nature’s diversity and strive to emulate those conditions to sustain multiple critical ecosystem services. To illustrate those services, the soil quality impact of harvesting crop residues are presented to show how careful, comprehensive monitoring of soil, water and air resources must be an integral part of sustainable bioenergy feedstock production systems. Preliminary analyses suggest that to sustain soil resources within the U.S. Corn Belt, corn ( Zea mays L.) stover should not be harvested if average grain yields are less than 11 Mg ha-1 (175 bu ac-1) unless more intensive landscape management practices are implemented. Furthermore, although non-irrigated corn grain yields east and west of the primary Corn Belt may not consistently achieve the 11 Mg ha-1 yield levels, corn can still be part of an overall landscape approach for sustainable feedstock production. Another option for producers with consistently high yields (> 12.6 Mg ha-1 or 200 bu ac-1) that may enable them to sustainably harvest even more stover is to decrease their tillage intensity which will reduce fuel use, preserve rhizosphere carbon, and/or help maintain soil structure and soil quality benefi ts often attributed to no-till production systems. In conclusion, I challenge all ISTRO scientists to critically ask if your research is contributing to improved soil and crop management strategies that effectively address the complexity associated with sustainable food, feed, fi ber and fuel production throughout the world.
Primitive pollen cone structure in Upper Pennsylvanian (Stephanian) Walchian conifers

A large number of conifer pollen cones associated with primitive walchian conifers, including Emporia , occur within an exceptionally preserved fossilized biota near Hamilton, Kansas, USA. The fossils are derived from channel deposits within the Upper Pennsylvanian (Stephanian B/C) Topeka Limestone and show excellent external morphology, internal anatomy, and cuticular features. Pollen cones are cylindrical, up to 5 cm long and 1 cm wide and are simply organized. Each pollen cone consists of a nonwoody central axis from which sporophylls diverge in a helical arrangement. Vascular tissue comprises a ring of tiny cauline bundles that divide at intervals to produce a single trace to each sporophyll. Sporophylls consist of a terete stalk and a heeled distal lamina. Sporangia are attached as a cluster on the adaxial surface of the sporophyll stalk. Stomata occur in one or two bands on the inner surface of sporophyll laminae and consist of guard cells surrounded by a ring of subsidiary cells, each with one overarching papilla. The Hamilton specimens provide conclusive evidence that pollen cones with a distinctive morphology were produced by some of the most ancient walchians from both North America and Europe. Contrary to traditional interpretations, these cones differ significantly from those of the Pinaceae. The broad geographic and stratigraphic distribution of this morphology reveals that conifer pollen cones similar to those at Hamilton are more widespread than previously suspected, and provides evidence for the potentially ancestral morphology of all conifer pollen cones.
Nanoclay-reinforced Polyacrylamide Composite: Synthesis, Structural and Mechanical Characterization

A facile electrophoretic deposition method was successfully applied to achieve novel nanoclay-reinforced polyacrylamide nanocomposite thin films. A special curled architecture of the re-aggregated nanoclay-platelets was identified, providing a possible source for realizing the interlocking mechanism in the nanocomposites. The curled architecture could be the result from strain releasing when the thin films were peeled off from the substrates. Through micro-/nano-indentation and in situ observation of the deformation during tensile test with an atomic force microscope (AFM), the localized deformation mechanism of the synthesized materials was investigated in further details. The results implied that a localized crack diversion mechanism worked in the synthesized nanocomposite thin films, which resembled its nature counterpart-nacre. The deformation behavior and fracture mechanism were discussed with reference to lamellar structure, interfacial strength between the nanoclays and the polyacrylamide matrix, and nanoclay agglomeration.
Electrocatalysis at a conducting composite electrode doped with a ruthenium(II) metallodendrimer.

A pentaerythritol-based metallodendrimer with RuIIterpyridine units was synthesized and tested as a mediator for the electrochemical oxidation of methionine (l-Met), cystine (l-Cys), and AsIII. A reversible oxidation of RuII was observed with the metallodendrimer as a solute in mixed acetonitrile−water solvents and as a component of carbon-based conducting composite electrodes. Mediated oxidation of the test species was observed. In aqueous solution, the composite electrode yielded a cyclic voltammetric peak current for the oxidation of l-Met in a 0.1 M phosphate buffer (pH 7.0) at 1.1 V vs Ag/AgCl. This anodic process was employed for amperometric detection in a flow system. Linear calibration curves were obtained over the range 1.0−10 μM Met and Cys. Using the criterion of the concentration yielding a signal 3 times the uncertainty of a blank, detection limits of 0.6 and 0.5 μM were calculated for Met and Cys, respectively. The slopes with three nominally identical electrodes varied by 10%.
A new force field model of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and acetonitrile mixtures.

Recently, we introduced a new force field (FF) to simulate transport properties of imidazolium-based room-temperature ionic liquids (RTILs) using a solid physical background. In the present work, we apply this FF to derive thermodynamic, structure, and transport properties of the mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM][BF4], and acetonitrile (ACN) over the whole composition range. Three approaches to derive a force field are formulated based on different treatments of the ion–ion and ion–molecule Coulomb interactions: unit-charge, scaled-charge and floating-charge approaches. The simulation results are justified with the help of experimental data on specific density and shear viscosity for these mixtures. We find that a phenomenological account (particularly, a simple scaled-charge model) of electronic polarization leads to the best-performing model. Remarkably, its validity does not depend on the molar fraction of [BMIM][BF4] in the mixture. The derived FF is so far the first molecular model which is able to simulate all transport properties of the mixtures, comprising RTIL and ACN, fully realistically.
Pathogenetic role for early focal macrophage infiltration in a pig model of arteriovenous fistula (AVF) stenosis.

PurposeArteriovenous fistula non-maturation because of a peri-anastomotic venous stenosis is currently a huge clinical problem for which there are no effective therapies.MethodsIn an attempt to fur...
Biological skeletal carbonate records changes in major-ion chemistry of paleo-oceans.

The history of the chemical evolution of seawater is of first-order importance given its fundamental role in a broad spectrum of geologic, geochemical, and paleontologic phenomena. A growing body of evidence for a more dynamic evolution of seawater chemistry than previously considered has been building over the past two decades. Central to this body of evidence are oscillating global trends, on a 100- to 200-million-year time scale, in the mineralogy of marine carbonate cements (1), late-stage salts in marine evaporites (2), and calcifying organisms that are interpreted to record secular change in seawater chemistry (3, 4). The degree to which the basic seawater signal has varied over the past 550 million years is, however, an issue that has been strongly debated in the literature (e.g., refs. 5–9). This primarily reflects the arguably equivocal nature of the evidence used to infer secular changes in seawater chemistry and the mechanisms for driving that change. Reconstructions of seawater chemical composition based on marine inorganic precipitate and fossil proxy records may be compromised by the influence of various environmental factors, and by the geochemical insults of diagenesis on their mineralogy and chemical composition (5, 10, 11). Complimentary modeling efforts that focus on constraining the mechanism(s) for driving substantial chemical change in seawater are challenged by the uncertainties associated with defining model input parameters (2, 5, 9). The degree to which the basic seawater signal has varied over the past 550 million years is an issue that has been strongly debated. In a recent issue of PNAS, Stanley et al. (12) provide compelling, experimentally derived evidence that the skeletal carbonate of biologically simple marine organisms, analogous to inorganic marine carbonate, has the potential to record faithfully changes in the major-ion chemistry of paleo-oceans. Their results, in concert with recently published …
Measurement of reduced, oxidized and total ascorbate content in plants

Ascorbate is one of the major antioxidant metabolites in plant tissues. This protocol describes a microplate-adapted colorimetric ascorbate assay, in which ferric ion is reduced by ascorbate to the ferrous ion. The ferrous ion reacts with alpha-alpha'-bipyridl to form a complex with characteristic absorbance at 525 nm. With the chemical reduction of any dehydroascorbate (DHA) in a sample, total ascorbate can be assayed using the alpha-alpha'-bipyridl method, and DHA can be estimated by subtracting the reduced portion from the total ascorbate pool. The assay is performed in microcentrifuge tubes and assessed in a 96-well plate reader. Reduced ascorbate, DHA and total ascorbate of at least 64 experimental samples can be analyzed easily in 1 d.
STUDENTS' PERCEPTIONS OF TEACHER CREDIBILITY AND LEARNING EXPECTATIONS IN CLASSROOM COURSES WITH WEBSITES

A growing number of community college faculty incorporate Internet technology into their course delivery, including the use of a supplemental Web site for classroom courses. This study employed hypothetical scenarios and experimental research design to examine students’ initial perceptions of teacher credibility and their expectations for learning in the presence of and absence of a course Web site. Three hypotheses predicted that the availability of a supplemental course Web site would positively influence certain student attitudes about the instructors and expected learning in the courses, but none of the hypotheses was supported. The neutral responses of these students stand in contrast to the very positive attitudes of instructors who create such sites and deem them to be essential to successful course delivery. The article concludes with a discussion of the disparate viewpoints of students and teachers.
A contrast enhancement filter for improving stent visibility in interventional X-ray fluoroscopy: an initial study

Low exposure X-ray fluoroscopy is widely used to guide some complicate interventional procedures. Given its inherent high noise, improving the visibility of interventional devices such as stents will greatly benefit the procedures. In this study, a contrast enhancement filter has been proposed to improve stent visibility. It is designed to selectively improve the contrast of stent contour segments without dramatically accentuating quantum and clinical background noises. To achieve this, convolution directional filter banks were applied to detect the edges and orientations of stent. Next, symmetry measures were used to extract symmetrical portions of the stent image. Those information were combined to generate a partial stent contour map. The contour map was then scaled and added back to the original image to get the stent in the image contrast enhanced. It is shown that this stent enhancement filter effectively improves stent visibility in the interventional X-ray fluoroscopy.
Professional Sports Experiences as Contested Racial Terrain

African-American athletes have been widely represented in the sporting world throughout the twenty-first century. Sport participation has been positive for the group and for American society as a whole by both aiding integration and providing opportunities, such as college scholarships, social mobility, etc. that may not have been available in other avenues. Comprising 78 % of the National Basketball Association and 67 % of the National Football League, African-Americans males’ overrepresentation as professional athletes seems to illustrate opportunities for the group unfettered by any major barriers (Lapchick 2011). However, contemporary scholars have debated whether or not sports are actually a way out of less than desirable economic and social situations for African-American males. Although most Americans, and athletes themselves, think of professional sports in terms of the fame and fortune experienced by the most successful athletes, this article examines the experiences that is perhaps most common among professional athletes through the lens of contested racial terrain.
Homogeneous alternating projection neural networks

Abstract The homogeneous form of the alternating projection neural network (APNN) performs as a content-addressable memory. We analyze and illustrate the characteristics and performance of the homogeneous APNN. Convergence of the iterative reconstruction becomes faster when the percentage of the clamped neurons, corresponding to known states, increases and the number of stored library vectors decreases. For a bipolar (±1) library, we demonstrate one-step convergence when the number of output neurons is sufficiently small. A new per-step minimization method for relaxation is introduced and is favorably contrasted in performance to other relaxation methods. We also propose a modified training procedure that requires neither a global norm operation nor division. Lastly, the noise characteristics of the APNN are examined and illustrated.
A Technology Commitment Model of Post-Adoption Behavior

Every year, individuals and organizations end up adopting licensing many competing software products. Yet, over time, much of the adopted software remains unused because users forgo the use of one software product for another adopted alternative. Although much research in the IS field has examined initial IS adoption, less is known about such post-adoption behavior. This article argues that a sense of "technology commitment" to one technology over other adopted alternatives is key to sustained post-adoption use intentions. By forwarding a technology commitment model, this article investigates the antecedents of technology commitment and its consequent effects on IS continuance. In the model, the article also examines how technological inertia moderates IS continuance intentions. Gathering empirical evidence from IS continuance intentions related to Webmail services, findings from the study offer interesting insights into the mechanics of continuance.
Identifying the principal protective antigenic determinants of type A botulinum neurotoxin.

The neurotoxins from Clostridium botulinum (BoNT serotypes A-G) exert their lethal effect by preventing the release of acetylcholine at the neuromuscular junction. As with tetanus toxin, immunization with a non-toxic fragment, the 50 kDa C-terminal portion of BoNT/A (H c ; residues 861-1296), protects mice against lethal challenges with the intact toxin. To locate the neutralizing epitopes, several protective monoclonal antibodies (mAbs) against BoNT/A-H c were isolated and cloned. Specific binding of the mAbs to BoNT/A-H c was demonstrated by surface plasmon resonance, with K d s in the range of 10 10 to 10 -1 M. These antibodies recognized a genetically engineered polypeptide (1150-1289) that was previously shown to induce protective immunity. Prior to the determination of the X-ray crystal structure of the tetanus neurotoxin H c fragment, molecular modelling studies indicated that it contained two highly solvent-exposed loops. Based on these predictions, two 25-mer H c -peptides corresponding to these two regions were synthesized and were demonstrated to bind the neutralizing mAbs. Mice immunized with the H c -peptides had high levels of antibodies that recognized BoNT/A-H c . However, immunizations with only one of the H c peptides protected when mice were challenged with BoNT/A. On the basis of these analyses, it should be possible to develop small peptides that could be useful in the design of future vaccines against these neurotoxins.
THE LATTICE OF IDEALS OF THE NEARRING OF COSET PRESERVING FUNCTIONS

Let G be a group and let N be a normal subgroup of G . The lattice of ideals of the nearring D ( N ) = { f : G → G | f (0) = 0 and f ( x + N) ⊆ f ( x ) + N for all x ∈ G } is determined. Keywords: near-rings, ideals, lattice Mathematics Subject Classification (1991): 16Y30 Quaestiones Mathematicae 24(1) 2001, 1-8
Does mandatory inpatient alcohol detoxification reduce emergency department recidivism, hospital admissions, and emergency medical services transports for patients with chronic, severe alcohol dependence?

Abstract Background: In Massachusetts, patients with chronic alcohol dependence can be committed to 30 days of mandatory inpatient alcohol detoxification (MAD). Study Objectives: To examine the effects of MAD on the number of emergency department (ED) visits, hospital admissions, and emergency medical service (EMS) transports. Methods: This retrospective study identified patients in our urban ED committed to MAD. We compared the number of ED visits and admissions to our hospital and Boston EMS transports to any facility in the 1, 3, and 6 months pre- and post-MAD, excluding the 30-day MAD period. Paired t tests were used for analysis of mean values across time. Results: Ten subjects were enrolled. Comparing pre- and post-MAD, the mean number of ED visits fell 6.5 to 2.7 ( p = 0.05) in the first month, 14.2 to 9.3 ( p = 0.18) in 3 months, and 25.6 to 17.7 ( p = 0.15) in 6 months. Mean number of hospital admissions declined: 1.3 to 0.1 ( p = 0.03) in 1 month, 2.3 to 0.9 ( p = 0.06) in 3 months, and 3.2 to 1.9 ( p = 0.08) in 6 months. Mean number of EMS transports fell 4.6 to 2.3 ( p = 0.21) in the first month, 9.2 to 5.6 ( p = 0.14) in 3 months, and 13.9 to 10.0 ( p = 0.26) in 6 months pre- and post-MAD. Conclusions: MAD was associated with an immediate reduction in ED visits and hospital admissions that did not remain statistically significant long term, and a non-significant reduction in EMS transports.
Present status of research on the physical constants at the (United States) National Bureau of Standards

The accuracy with which our present standards of length, mass, and time can be measured is discussed. The difficulties in determining certain derived standards needed to proceed from primary standards to physical constants as standards are summarized. National Bureau of Standards measurements of such physical constants as the velocity of light, the gyromagnetic ratio of the proton, cyclotron rcsonance of the proton, fundamental constants derived with the aid of the resonance constants, and the faraday are described. It was concluded that length and time can be satisfactorily defined in terms of physical constants, but the inaccuracies in the measurement of mass cannot be overcome at the present time. It is suggested that it would be more advantageous to go directly to a four standard system by defining a fourth independent standard in terms of a physical constant which is precisely related to one of the electric quantities. (M.H.R.)
Multiple scattering in a synthetic foggy atmosphere experimental results

Abstract Measurements of polarized radiances multiply scattered by a plane-parallel slab containing spherical scatterers of known single scattering properties are described and compared with calculations made with scalar radiative transfer theory and with a vector Monte Carlo calculation. These measurements were obtained with a newly designed light-scattering photometer which simulates quite closely the requirements of the theory for the plane-parallel monochromatic beam. A polystyrene latex of narrow size distribution and of the average diameter .245 μm was investigated at various concentrations. Two wavelengths were used at four angles of incidence, and the angular variation of the Stokes radiance vector was measured in both the transmitted and back-scattered half-spaces. The experimental results are in excellent accord with the theoretical calculations. Accordingly, this experimental arrangement can serve as an analog computer for systems for which the theory is either intractable or too complex for machine calculations.
Knockdown Screens to Knockout HIV-1

Three recent screens use siRNAs to identify host genes that are critical for HIV-1 replication. These screens have uncovered hundreds of human genes not previously known to be commandeered by the virus during infection. Although some caveats remain, this screening approach opens up a new landscape of viral-host interactions for future exploration.
The redistribution equilibria of silanic hydrogen with chlorine on methylsilicon moieties

Abstract The scrambling equilibria of silanic hydrogen with chlorine atoms on various combinations of mono-, di-, and trimethylsilicon moieties have been determined by proton nuclear magnetic resonance. The data have been evaluated in terms of sets of equilibrium constants which show that at equilibrium, the exchangeable hydrogen atoms prefer to be with the silicon moiety bearing the least number of methyl groups.
Carbon Dioxide Measurements with and without Barium Peroxide in Electrolytic Studies with and without a Supporting Electrolyte

Abstract This research deals with the quantitative formation of carbon dioxide in electrolytic oxidation reactions. The electrolytic reactions were run with barium peroxide to generate the superoxide anion at the anode. With the organic compounds used in these electrolytic studies we needed to develop a method where we could determine the amount of carbon dioxide liberated from these compounds with the superoxide anion. This method degasses an acidified solution with dry nitrogen, which carries the carbon dioxide to a standard solution of sodium hydroxide. Titration of the sodium hydroxide solution with standardized hydrochloric acid revealed the amount of carbon dioxide formed in the reaction after precipitation of the carbonate ions with barium chloride. Blank runs with the apparatus using anhydrous sodium carbonate produced 99% plus results of recovered carbon dioxide from the sodium carbonate.
War and PC: Obstacles to free thought

MJr tOpic is the relat ionship between "political correctness" and academic e e d o m dur ing wartime. I will offer two sets of claims about that topic. The first involves "political correctness," which I unde r s t and to m e a n h u m a n vulnerability to social pressure to adopt one or ano t he r position. So understood, political correctness is ubiquitous. This kind of vulnerability is hardly l imited to left-leaning intellectuals, and the pressure is likely to be especially strong when national security is at risk. I a t tempt to explain what makes political correctness possible, showing that people learn from the beliefs of relevant others, and also that they want, naturally enough, to avoid social opprobr ium. The second claim is that academic f r e e d o m should be unde r s tood to entail freedom from institutional discrimination against any point of view. Protection of academic f reedom, so unders tood , is quite important . But in a way, this unders tanding of academic f r e e d o m is relatively narrow, allowing universities to punish students or faculties when the reason is no t to punish viewpoints, but to ensure the successful p e r f o r m a n c e o f the educat ional mission. My remarks will come in two parts. The first par t at tempts to clarify the idea of political correctness, with special r e f e r ence to times of war. The second explores the re la t ionship be tween academic f r e e d o m and d i sc r imina t ion against certain points of view, again with special r e fe rence to p u n i s h m e n t of unpopu la r views dur ing wartime.
Century to millennial-scale temperature variations for the last two thousand years indicated from glacial geologic records of Southern Alaska

Abstract Comparisons of temperature sensitive climate proxy records with tree-ring, lichen and radiocarbon dated histories from land-terminating, non-surging glaciers for the last two millennia from southern Alaska identify summer temperature as a primary driver of glacial expansions. Two major intervals in the Alaskan chronology of glaciation, during the First Millennium AD (FMA) and again during the Little Ice Age (LIA), are evident as broad times of cooling and ice expansion. These two intervals are respectively followed by ice retreat coincident with the Medieval Warm Period (MWP) and contemporary warming, and together correspond with millennial-scale variations recognized in the North Atlantic. The FMA advance appears to be of similar extent as the subsequent LIA expansions indicating a uniformity of forcing over the past two millennia.
Motion artifact as a pitfall in diagnosis of meniscal tear on gradient reoriented MRI of the knee

Objective Reorientation of the phase and frequency encoding gradients is frequently performed for knee MRI to improve visualization of the cruciate ligaments. This technique allows pulsation artifacts arising from the popliteal vessels to be redirected away from the intercondylar notch. The objective of this study was to evaluate the potential for this method to result in false-positive depictions of meniscal tears based on subtle patient motion. Materials and methods Magnetic resonance imaging of the knee was performed in five patients using gradient reorientation. Repeat examinations were then performed following deliberate instruction to the patients regarding the importance of refraining from moving the extremity. Results The MRI performed with gradient reorientation demonstrated apparent meniscal tears using standard criteria. However, the repeat examinations following deliberate patient instructions to refrain from moving demonstrated the affected menisci to be normal in all patients. Conclusion Knee motion during image acquisition may result in ghosting artifacts of relatively high signal intensity structures such as marrow within the femoral condyles and hyaline cartilage along the articular surfaces. These artifacts may traverse the menisci on gradient-reoriented images and result in confusion with meniscal tear. Whereas gradient reorientation is a valuable tool for improving depiction of the cruciate ligaments, one must be aware of the potential for this technique to result in simulation of meniscal tears.
Endovascular Repair of Ruptured Aortic Aneurysms Using Carbon Dioxide Contrast Angiography

Background Endovascular aneurysm repair (EVAR) has become a common approach to the management of ruptured abdominal aortic aneurysms (rAAA). The use of iodinated contrast during EVAR for rAAA has several disadvantages, including contrast nephropathy, potential allergic response, and the need for high-pressure injection. We evaluated the use of carbon dioxide (CO 2 ) as the primary contrast agent for endovascular repair of ruptured aortic aneurysms. Methods Between December 2007 and July 2009, we retrospectively reviewed our experience with patients undergoing endovascular repair of rAAA, with CO 2 as the principal contrast agent, and compared them with patients who underwent EVAR using iodinated contrast. Results Four patients underwent endovascular repair of rAAA with CO 2 angiography (group 1) and seven with iodinated contrast (group 2). The mean age of the patients was not different between groups ( p = 0.353). Patients in group 1 received a mean of 443 ± 99 mL of CO 2 and 4.3 ± 8.5 mL of iodinated contrast. Patients in group 2 received 110.2 ± 37.6 mL of iodinated contrast ( p p = 0.491). In patients who survived to discharge, the change in creatinine between admission and discharge was greater in group 2 although not statistically significant (0.25 ± 0.19 mg/dL for group 1 vs. 0.58 ± 0.25 mg/dL for group 2, p = 0.066). There was no significant difference in length of stay between group 1 (intensive care unit, 1.00 ± 0.82 days; hospital, 4.25 ± 0.96 days) and group 2 (intensive care unit, 3.60 ± 3.44 days; hospital, 9.00 ± 6.60 days). Conclusions Endovascular repair of rAAA using CO 2 as a contrast agent is technically feasible and safe. The potential benefits of CO 2 angiography support the continued use of CO 2 in cases of ruptured aneurysms. Further studies are necessary to determine whether CO 2 improves survival and limits the progression of renal dysfunction after endovascular repair of rAAA.
Skin tumorigenesis in mice by petroleum asphalts and coal-tar pitches of known polynuclear aromatic hydrocarbon content

Abstract Benzene solutions of eight petroleum asphalts and two coal-tar pitches of known polynuclear aromatic hydrocarbon content were applied topically to Swiss mice. Epidermal carcinomas and papillomas were observed in over 90% of coal-tar pitch treated animals. Only one carcinoma and 5 papillomatous growths were observed in 218 mice treated with asphalts. The relatively low tumor incidence resulting from the asphalt treatments precluded an evaluation of a possible relationship between polynuclear aromatic hydrocarbon content and tumorigenicity. An analytical method for determining the polynuclear aromatic hydrocarbon content of asphalt and coal-tar pitch is presented, and values are given for 17 such compounds in each of the test materials.
Microscopic studies of dental tissues. I. Electron microscopy of tooth structure.

Abstract The applications of the electron microscope in the study of dental tissues have been described. Some of the results of the investigations of the structure of mature and developing enamel and dentine, and various other tissues, have been presented.
Spin-glass behavior in a giant unit cell compound Tb117Fe52Ge113.8(1)

In this paper we demonstrate evidence of a cluster spin glass in Tb117Fe52Ge113.8(1) (a compound with a giant cubic unit cell) via ac and dc magnetic susceptibility, magnetization, magnetic relaxation and heat capacity measurements. The results clearly show that Tb117Fe52Ge113.8(1) undergoes a spin glass phase transition at the freezing temperature, ~38 K. The good fit of the frequency dependence of the freezing temperature to the critical slowing down model and Vogel-Fulcher law strongly suggest the formation of cluster glass in the Tb117Fe52Ge113.8(1) system. The heat capacity data exhibit no evidence for long-range magnetic order, and yield a large value of Sommerfeld coefficient. The spin glass behavior of Tb117Fe52Ge113.8(1) may be understood by assuming the presence of competing interactions among multiple non-equivalent Tb sites present in the highly complex unit cell.
A closure-approximation calculation of a pion double-charge-exchange reaction

Abstract A pion double-charge-exchange reaction is studied by using a closure approximation to sum the intermediate nuclear states. The calculated first minimum of the differential cross section of 18 O (π + , π − ) 18 Ne is at 30°, which is much smaller than the value of the optical-model calculation. However, the closure-approximation model cannot describe the data even when the polarization of the 16O core is treated properly.
Expressions for batched searching of sequential and hierarchical files

Batching yields significant savings in access costs in sequential, tree structured, and random files. A direct and simple expression is developed for computing the average number of records/pages accessed to satisfy a batched query of a sequential tile. The advantages of batching for sequential and random files are discussed. A direct equation is provided for the number of nodes accessed in unhatched queries of hierarchical files. An exact recursive expression is developed for node accesses in batched queries of hierarchical files. In addition to the recursive relationship, good, closed-form upper- and lower-bound approximations are provided for the case of batched queries of hierarchical files.
Transient heat conduction in non-homogeneous spherical systems

A comprehensive study encompassing a general analytical development and an archival presentation of results is made for transient heat conduction in thermally coupled spherical regions. The system consists of a sphere and its surrounding environment, each region having different thermal properties and different initial temperatures. The general closed form solution, which accommodates an arbitrary inital temperature distribution in the sphere, is specialized to apply to a number of interesting problems. Among these, the situation in which the sphere and the surroundings are initially at different uniform temperatures constitutes a basic problem in the theory of heat conduction. Correspondingly, a comprehensive presentation of transient temperature histories is made for various locations in the sphere and in the surroundings, with relevant thermal property ratios serving as parameters. Characteristics such as the duration of the transient period and the penetration depth of the temperature field into the surroundings are illuminated. Another interesting situation is that in which the thermal conductivity of the sphere is much greater than that of the surroundings, so that the sphere temperature may be regarded as being spatially uniform. In addition to a presentation of temperature histories, the conditions are identified under which the assumed spatial uniformity of the sphere temperature is valid. For the case of a metallic sphere situated in a gaseous environment, it is demonstrated that the transient response can be represented by a single universal curve.
Nonlinear Fourier correlation

Fourier correlators perform space-invariant linear filtering on all input points, so they can identify and locate patterns in parallel. Each output point is a weighted sum of components of the Fourier transform of the input, so the discriminants used are inherently linear. As most practical problems are not linearly discriminable, that causes a problem. This paper describes a quite general solution involving nonlinear combining of nonlinearly processed outputs from multiple Fourier masks. The design of the masks and nonlinearities allows very powerful nonlinear discrimination that preserves the space-invariant feature that makes Fourier correlators attractive. Given a set of target-class images, henceforth referred to as the training set or trainers, the algorithm developed herein computes an ordered set of classifier filters - Generalized Matched Filters (GMFs) threshold values. An unlabeled image is applied to the classifier filter set, hereafter referred to as super-generalized matched filter (SGMF). If the peak response of any of the classifier filters (GMFs) to the unlabeled test image exceeds the threshold level the decision is made in favor of labeling the image as target-class otherwise it is labeled non-target- class.
Political Support for Decentralization: An Analysis of the Colombian and Venezuelan Legislatures

Policy makers have supported decentralization as the solution to a diverse range of problems. Its popularity is rivaled only by its irony, as decentralization requires an explicit decision on the part of the national government to give away power and authority to subnational levels of government. In Latin America, this decision came during a period of extensive economic adjustment characterized by the significant involvement of international financial institutions. Both the timing of decentralization and its popularity with organizations such as the World Bank, led many to assume that these institutions were responsible for decentralization (see, for instance, Rosenfeld 1995). At the same time governments have embraced and implemented decentralization more extensively than originally conceived by the international agencies that suggested it. This makes it important to identify the domestic constituencies responsible for promoting it to understand the political motivations behind decentralization. Most studies have focused on presidents or nongovernmental actors and have ignored the role of the legislature. Yet understanding the role of the congress in Colombia and Venezuela is important as deputies both authored decentralizing legislation and actively tried to influence its scope, pace, and character even when the bill was initiated by the executive branch. Thus, studying
Simultaneous transport of parent and daughter compounds in aquifers with linear first-order sorption kinetics

Abstract In soils, daughter compounds may be generated from a parent compound by microbial metabolism, chemical reactions, radioactive decay, or other mechanisms. These daughter compounds are also acted upon by soil physical, chemical and biological processes. A system often referred to as a cascade or chain of compounds system results. While a great deal of attention has been given to this problem with the linear equilibrium assumption applied uniformly to all transport and reacting compounds, little attention has been given to the simultaneous transport and fate of a parent-daughter chain with a first-order rate assumed for the adsorption-desorption kinetics of each compound and with the soil partitioned into three sorption classes. A general one-dimensional cascade or chain model for the simultaneous transport of parent and daughter compounds in sorbing, homogeneous, water table aquifers is presented. The model is based on an advective-dispersive mass accounting formulation for both compounds and includes: (a) first-order rate of conversion of parent to daughter; (2) first-order rates of loss of either parent or daughter or both due to metabolism, chemical reaction and/or irreversible processes; (3) partitioning of the aquifer material into three sorption classes, namely mildly sorbing, strongly sorbing and organic matter; (4) linear first-order kinetic rules for adsorption and desorption operating on each of the sorbing soil fractions for each compound; (5) constantly emitting sources of rectangular shape of parent compound; and (6) mass accounting boundary conditions; and a tailorable initial distribution on [0, ∞). Mathematical analysis yields a coupled, linear system of equations including two transport and fate equations, initial and boundary data, and six kinetic rules, namely three each for parent and daughter compound. A numerical scheme for solving the system of equations was developed using readily available procedures since analytical solutions could not be found. Solutions for scenarios based on leaking underground sources are presented.
Computer and Experimental Models of Transient Flow in a Pipe Involving Backflow Preventers

Transient flow in a pipe was studied using both experimental and computer models. In the present study, three different numerical models: The method of characteristics model, the axisymmetrical model, and the implicit scheme model are utilized and compared. Experiments for transient flow in a simple pipeline have been conducted to verify the results from the computer models. It was found that head loss coefficient for the 1D models, such as the method of characteristics model and the implicit scheme model, should be much bigger than the Darcy-Weisbach frictional coefficient. Experiments for transient flow with the backflow preventer in a pipe were conducted. Results show that backflow preventer serves as a strong damper to the water hammer generated by the hydraulic transients. Numerical investigation simulating a backflow preventer in transient flow has been performed in this study. It was found that different values of head loss coefficient should be applied for the upstream and downstream of backflow preventer. All of the numerical models were compared with the experiments. The results of different computer models developed in the present study agree well with the experimental data.
Polymeric composite bipolar plates for vehicle applications

Abstract At present membrane electrode assembly performance levels and stack operating conditions of PEM fuel cells, a plate area specific resistance of less than approximately 20 mΩ cm 2 and a plate thickness of less than 2 mm are required to meet the vehicular volumetric power density target (>2 kW l −1 ). It is, however, difficult to meet these aggressive requirements, and simultaneously obtain good mechanical properties when using polymeric plate materials. Polymers become brittle and break frequently at the high conductive filler loadings (e.g., >50 v/o graphite) required for high conductivity. This study investigates a potential approach for obtaining high plate conductivity at low conductive filler loadings, thus enabling high volumes of thin and ductile plates to be manufactured at low scrap rates.
Effects of dried algae Schizochytrium sp., a rich source of docosahexaenoic acid, on growth, fatty acid composition, and sensory quality of channel catfish Ictalurus punctatus

Abstract A laboratory study was conducted to investigate the effect of supplementation of dried algae Schizochytrium sp., a rich source of 22:6 n-3, on growth, fatty acid composition, and sensory quality of channel catfish Ictalurus punctatus . Five isonitrogenous (28% crude protein) and isocaloric (2.78 kcal/g), all-plant diets were formulated to contain 0, 0.5, 1.0, 1.5, and 2.0% dried algae. These diets were fed once daily to satiation for 9 weeks to channel catfish with an average initial weight of 20.4 g per fish in a flow-through system. Fish fed diets containing 1.0% and 1.5% dried algae gained significantly more weight than fish fed diets containing 0% and 0.5% dried algae. Feed efficiency ratio of fish fed 0.5%–2.0% dried algae was significantly greater than that of fish fed the control diet without dried algae. No significant differences were observed in fillet protein, fat, and moisture concentrations, or overall preference and fishy taste scores among fish fed various levels of dried algae. As dietary levels of dried algae increased, 20:5 n-3, 22:6 n-3, total n-3, total n-3 long-chain polyunsaturated fatty acids (LC-PUFAs), 22:5 n-6, and total n-6 LC-PUFAs in the fillet generally increased. These results indicate that supplementation of dried algae increases weight gain of fish and feed efficiency ratio of the fish. Addition of 2% dried algae in the diet markedly improves the levels of 22:6 n-3 and total n-3 LC-PUFAs in the edible tissue of fish. Dried algae Schizochytrium sp. can play an important role to supply essential fatty acids to fish, and humans who consume the fish product enriched with n-3 LC-PUFAs.
Lithium ion cells using a new high capacity cathode

Abstract The application of a new series of layered first row transition metal oxides as cathodes in lithium ion cells is demonstrated. The cathodes were made from a quaternary oxide of lithium, chromium, and manganese belonging to the compositional series Li x Cr y Mn 2− y O 4+ z with x >2.2, 0 y z ≥0. The layered structure is stabilized by the partial substitution of the manganese by chromium and lithium atoms and by the partial or complete oxidation of the manganese to the +4 oxidation state.
Similarity solutions of population balances

Abstract Population balances containing two independent variables can sometimes be transformed with a similarity transformation into an ordinary integro-differential equation. The possibility of such a transformation, however, does not mean that a similarity solution exists. A similarity solution may exist and can represent the exact solution of the population balance at long times if a certain criterion, established in this paper, is satisfied. For physical processes like coagulation of colloids, aging of supported metal catalysts, and granulation, this criterion is applied and conditions under which a similarity solution may exist identified.
Use of oral contraceptives in women of older reproductive age

Abstract Evidence of increased risk for cardiovascular disease in oral contraceptive users of older reproductive age is based on early data involving formulations containing higher doses of estrogen and progestin than those in use today. In addition, early studies included patients who would not receive oral contraceptives with today's more stringent prescribing criteria. When these data were carefully analyzed, a significant increase in myocardial infarction was noted only in oral contraceptive users with concemitant risk factors for cardiovascular disease. Analysis of other studies also showed a significant increase in the incidence of cardiovascular disease and mortality only in oral contraceptive users older than age 35 years who smoked. A recent long-term cohort study of women without risk factors for cardiovascular disease who mainly used oral contraceptives containing ≤50 μg estrogen showed no increased risk of myocardial infarction or cerebrovascular accident with oral contraceptive use. Use of oral contraceptives containing