cssi/SciSciGPT-SciSciNet huggingface dataset:
Ester and related derivatives of ring N-pentafluorobenzylated 5-hydroxymethyluracil. Hydrolytic stability, mass spectral properties, and trace detection by gas chromatography-electron-capture detection, gas chromatography-electron-capture negative ion mass spectrometry, and moving-belt liquid chromatography-electron-capture negative ion mass spectrometry.

Abstract One consequence of radiation damage to DNA is the conversion of thymine to 5-hydroxymethyluracil (HMU). In order to sensitively detect this DNA adduct by gas chromatography (GC) or high-performance liquid chromatography (HPLC) with electron-capture detection techniques, it is necessary to derivatize it. This study was designed to select an optimum ester derivative of the aliphatic hydroxyl group on HMU. N 1 ,N 3 -Bis(pentafluorobenzyl)-HMU was formed as a parent derivative, and from this a series of esters. Also O-pentafluorobenzyl and O-tetrafluorobenzyl ether derivatives were prepared. Of the esters the pivalyl derivative was the best choice because it formed easily, was relatively stable to aqueous hydrolysis ( t 1 2 = 9.8 days at pH 11.5, 24°C) and gave a response at fmol levels by GC and LC comparable to that of the ethers. Unanticipated was a good response as well for the parent derivative, a free hydroxyl compound, by GC and LC at this level. The work also demonstrates a high performance by LC-electron-capture negative ion mass spectrometry with a belt interface for the trace detection of derivatives of this type.
A formalized proof of Dirichlet's theorem on primes in arithmetic progression

We describe the formalization using the HOL Light theorem prover of Dirichlet's theorem on primes in arithmetic progression. The proof turned out to be more straightforward than expected, but this depended on a careful choice of an informal proof to use as a starting-point. The goal of this paper iis twofold. First we describe a simple and efficient proof of the theorem informally, which iis otherwise difficult to find in one self-contained place at an elementary level. We also describe its, largely routine, HOL Light formalization, a task that took only a few days.
Security through Collaboration in MANETs

It is well understood that Mobile Ad Hoc Networks (MANETs) are extremely susceptible to a variety of attacks, and traditional security mechanisms do not work well. Many security schemes have been proposed that depend on cooperation amongst the nodes in a MANET for identifying nodes that are exhibiting malicious behavior such as packet dropping, packet modification, and packet misrouting. We argue that in general, this problem can be viewed as an instance of detecting nodes whose behavior is an outlier when compared to others. In this paper, we propose a collaborative outlier detection algorithm for MANETs that factors in a nodes reputation. The algorithm leads to a common outlier view amongst distributed nodes with a limited communication overhead. Simulation results demonstrate that the proposed algorithm is efficient and accurate.
Protecting the Supply Chain: Differentiating Financial Distress at Large and Small Suppliers

The paper examines whether it is better to separate a model/sample to account for differences between large and small firms when developing a predictive tool to identify which companies are likely to become distressed, and therefore at risk to the supply chain. Previous research has scaled data by size of company but has not considered whether the process leading to financial distress may be different depending on firm size.
Purification and Comparative Properties of a Pyrimidine Nucleoside Phosphorylase from Bacillus stearothermophilus

Abstract The pyrimidine-nucleoside:orthophosphate ribosyltransferase (EC 2.4.2.2), or pyrimidine nucleoside phosphorylase, from Bacillus stearothermophilus has been purified and compared with similar enzymes from Bacillus subtilis and Escherichia coli. The enzyme is stable at 60°, appears to be induced by either uridine or thymidine, and has a molecular weight of approximately 78,000. Unlike nucleoside phosphorylases from most other sources, the thermophile enzyme catalyzes the phosphorolysis of both thymidine (apparent Km = 3.8 x 10-4 m) and uridine (apparent Km = 2.5 x 10-4 m) and, in the synthetic direction, does not distinguish between ribose 1-phosphate and deoxyribose 1-phosphate. It differs from E. coli and B. subtilis nucleoside phosphorylases in many properties including molecular weight, substrate specificity, thermostability, and induction properties.
Born in China

Abstract International adoption has been presented in the literature almost exclusively from a dominant western perspective with little consideration for that of the sending countries. This study seeks to capture Chinese perceptions of international adoption. The inextricable relationship between China's family planning policies and the placing of orphans in the diaspora for adoption led to a sample which included government officials (N = 12), welfare institution administrators (currently in China, the official term for an orphanage is “welfare institution”) (N = 15), and a non-specific adult population (N = 180). Findings indicated that overall participants viewed international adoption as providing positive opportunities for abandoned children, with government and welfare institution personnel viewing it as an appropriate response to an overburdened system. They also pointed to the government's active role in post-placement monitoring to be integral to the success of China's international adoptions. Co...
A 56-year-old man with hypercalcemia.

He has no symptoms, but his liver is palpable and his calcium, glucose, and creatinine concentrations are elevated. What is the cause?
Transformation of data traversals and operations in application programs to account for semantic changes of databases

This paper addresses the problem of application program conversion to account for changes in database semantics that result in changes in the schema and database contents. With the observation that the existing data models can be viewed as alternative ways of modeling the same database semantics, a methodology of application program analysis and conversion based on an existing-DBMS-model-and schema-independent representation of both the database and programs is presented. In this methodology, the source and target databases are described in terms of the association types of a semantic association model. The structural properties, the integrity constraints, and the operational characteristics (storage operation behaviors) of the association types are more explicitly defined to reveal the semantics that is generally hidden in application programs. The explicit descriptions of the source and target databases are used as the basis for program analysis and conversion. Application programs are described in terms of a small number of “access patterns” which define the data traversals and operations of the programs. In addition to the methodology, this paper (1) describes a model of a generalized application program conversion system that serves as a framework for research, (2) presents an analysis of access patterns that serve as the primitives for program description, (3) delineates some meaningful semantic changes to databases and their corresponding transformation rules for program conversion, (4) illustrates the application of these rules to two different approaches to program conversion problems, and (5) reports on the development effort undertaken at the University of Florida.
Isoform-specific enhancement of adenylyl cyclase activity by n-alkanols.

Background: Numerous studies suggest that cAMP signaling pathways play important roles in the development of and predisposition to alcoholism. Our previous study showed that cAMP generation by various isoforms of adenylyl cyclase (AC) exhibits a broad spectrum of responses to ethanol in the human embryonic kidney (HEK) 293 cell system overexpressing individual AC isoforms. These findings suggest that the target of ethanol’s action in the cAMP-generating system is AC. However, it is unknown if the action of ethanol is direct or indirect. Methods: The effect of a series of n-alkanols (ethanol to decanol) on dopamine (DA)–stimulated activity of AC isoforms type 6, 7, and 9 (AC6, AC7, and AC9) were examined in transfected HEK293 cells by cAMP accumulation assay. Results: n-Alkanols increased DA-stimulated cAMP production in an AC isoform-specific manner, and displayed the alcohol cutoff phenomenon (defined as the carbon chain length beyond which there is no further increase in the potency of an ascending series of n-alkanols). The n-alkanol cutoffs for AC6, AC7, and AC9 are butanol (C4), pentanol (C5), and equal to or greater than decanol (C10), respectively. Conclusion: The results clearly indicate that, in the HEK293 expression system, the alcohol cutoff effect for n-alkanol potentiation of DA-stimulated AC activity is AC isoform specific. These results strongly suggest that alcohols interact directly with AC molecules.
A simplified analysis of the optical bistability of multiple quantum well etalons

An analysis of static room-temperature-operation characteristics of a reflection-mode semiconductor multiple-quantum well etalon by a simplified two-level system formula of optical nonlinear properties and a computer simulation is presented. In the calculation for a GaAs/AlGaAs multiple-quantum-well etalon using the parameters reported in experimental measurement, it is shown that the very large excitonic optical nonlinearity is not effectively utilized for the optical bistable operation. This occurs because the effective positive-feedback mechanism which increases the etalon internal light intensity is suppressed when a hardly saturable background interband absorption tail is larger than a few thousand cm/sup -1/ at a wavelength where the large excitonic dispersive nonlinearity is observed. >
FREQUENCY OF ALARM BARKS IN TWO BLACK-TAILED PRAIRIE DOG TOWNS

Strm7nary.-The frequency of alarm barks of prairie dogs was found to increase as the distance from an observer to the prairie dog decreased. This orderly relarionship occurred in both a town heavily visited by tourists and in an isolated town. However, the frequency of barking, the distance at which barking began, and the distance between the observer and the prairie dog before the prairie dog retreated into in burrow were all greater for the prairie dogs in the isolated town.
Well-posedness Results for Models of Elastomers

Existence and uniqueness of weak solutions are shown for different models of the dynamic behavior of elastomers. The models are based on a nonlinear stress-strain relationship (satisfying a locally Lipschitz and affine domination property) and incorporate hysteretic effects as well. The results provide alternatives to previous theories that required monotonicity assumptions on the nonlinearities. Results with a nonlinear constitutive law and nonlinear internal dynamics are presented for the first time.
FXR acetylation is normally dynamically regulated by p300 and SIRT1 but constitutively elevated in metabolic disease states

The nuclear bile acid receptor FXR is critical for regulation of lipid and glucose metabolism. Here, we report that FXR is a target of SIRT1, a deacetylase that mediates nutritional and hormonal modulation of hepatic metabolism. Lysine 217 of FXR is the major acetylation site targeted by p300 and SIRT1. Acetylation of FXR increases its stability but inhibits heterodimerization with RXRalpha, DNA binding, and transactivation activity. Downregulation of hepatic SIRT1 increased FXR acetylation with deleterious metabolic outcomes. Surprisingly, in mouse models of metabolic disease, FXR interaction with SIRT1 and p300 was dramatically altered, FXR acetylation levels were elevated, and overexpression of SIRT1 or resveratrol treatment reduced acetylated FXR levels. Our data demonstrate that FXR acetylation is normally dynamically regulated by p300 and SIRT1 but is constitutively elevated in metabolic disease states. Small molecules that inhibit FXR acetylation by targeting SIRT1 or p300 may be promising therapeutic agents for metabolic disorders.
Benching Jim Crow: the Rise and Fall of the Color Line in Southern College Sports, 1890–1980

Benching Jim Crow: the Rise and Fall of the Color Line in Southern College Sports, 1890–1980, by Charles H. Martin, Urbana, University of Illinois, 2010, xxiv + 374 pp., note on sources, index, $30...
Nuclear vacuolar acantholytic vesicular dermatitis associated with leukocytoclastic vasculitis

A 48-year-old obese white woman had had a recurrent vesicular eruption for the previous 5 years. This eruption involved almost all parts of the body, including vaginal mucosa. The plantar and palmar surfaces were not involved. Eruptions start with a prodromal phase: 24 to 48 hours prior to the eruption, the normal-appearing skin becomes painful. A reddish discoloration occurs, and vesicles form within a half hour. The histologic features of the vesicles are unique in that they contain acantholytic cells. The nuclei of these cells are vacuolated and contain a reddish, "target"-appearing substance. The underlying corium shows a necrotizing leukocytoclastic vasculitis. The only effective medication for this disease is cyclophosphamide. Pathogenesis is discussed and is compared with that of other vesiculo-bullous acantholytic lesions with that of leukocytoclastic vasculitis. To the best of our knowledge, this disease appears to be unique.
The “Efficiency Transient Control” Concept for Optimal Load Control in Kaplan Turbine Hydroelectric Installations

In the case of Kaplan turbines the consideration of the efficiency parameter is critical from the control strategy synthesis viewpoint. As it is not essential in hydrosystem analysis, explicit efficiency parameter relationships have not been deployed to date for linearized Kaplan mathematical models used in control design. The “efficiency transient control” concept is developed herein. Basically, this approach purports to optimize transient behavior by controlling so as to decrease efficiency during the early transient portion of load rejection and likewise maximizing efficiency for the load acceptance case. For each perturbation this method leads to minimal flow change and, therefore, minimal over or under-pressures. As applied to a dominant gate with blade follow-up control scheme, the efficiency transient control concept prescribes the appropriate delay to be employed for optimum performance within the constraint of a follow-up device. Where the early transient deviates from best efficiency operation, a return to steady-state or “cam” operation occurs as the follow-up. The standard equations describing Kaplan turbine operation in linearized form by partial derivatives have been revised to include the efficiency parameter explicitly and now present a comprehensive and intelligible approach to Kaplan turbine control synthesis. The effect of the efficiency transient control upon system stability is analyzed and recommendations are made for desirable deployment. Application to nonlinear system operation is discussed. The efficiency transient control is compared with present day control schemes to assess their effectiveness. It is determined that a delay imposed upon the blades for the load-on case is suboptimal performancewise. The one-to-one gate-to-blade control is optimal in that case.
Occurrence of Sport Fish in a Commercial Net Fishery in Kentucky

Abstract Commercial fishermen reported removing 1,006 sport fishes from their nets during the 5-month 1980-1981 season. Observations of field monitors who accompanied these fishermen during retrieval operations revealed that the commercial gill nets and trammel nets (89-114 mm bar mesh) used for harvesting buffalofish (Ictiobus spp.) and common carp (Cyprinus carpio) in two mainstream Kentucky reservoirs had minimal impact on sport fish. The sport-fish catch was less than 1/1,000 m of net, with 65% of those in good condition when released. No largemouth bass (Micropterus salmoides) mortality was observed in the 39 km of gear monitored.
A Continous-Review s, S Inventory System with Arbitrary Interarrival Distribution between Unit Demand

For a continuous-review inventory system where demand is defined by a discrete-valued process with units withdrawn from stock one at a time and where the interarrival times between successive demands are independently and identically distributed, the transient and steady-state distribution for the position inventory are derived when operating under an s, S policy. This paper shows that the limiting distribution of the position inventory is uniform over the set s + 1, ', S and is independent of the distribution of the interarrival times. When instantaneous delivery of orders is allowed, the problem is equivalent to an independent stand-by system consisting of Q = S-s operating elements subject to failure, where, following the failure of the last operating element, all Q failed elements are immediately repaired or replaced by Q new identical elements.
How I do it — Necrosectomy in acute pancreatitis

Diagnostic objectives in the management of necrotizing pancreatitis include determining the anatomic extent of necrosis by computed tomography (CT) scan with vascular enhancement, the physiologic assessment of severity, ascertaining the etiology of pancreatitis, and distinguishing between patients who have sterile and infected necrosis. Treatment objectives in severe pancreatitis include: maximizing fluid resuscitation by Swan Ganz monitoring, in which the object of therapy is to create a hyperdynamic circulation maximizing cardiac index, providing mechanical ventilatory support when needed, and utilizing antibiotics on a presumptive basis in patients with more than 25% necrosis of the colon is often necessary. Triple lumen Davol catheters are used for irrigation with Chloropactin, delivered at a rate of 100–300 ml/h. Suction drainage is not employed. A No. 40 siliconized chest tube is used for gravity drainage. Open packing is preferred in patients with extensive necrosis of pancreatic and peripancreatic tissue or in patients who become infected soon after the onset of symptoms. Patients who are packed open are returned to the operating room every 2–3 days until there is no further visual or CT scan evidence of necrotic tissue or fluid. The literature shows 40%–50% of patients treated by closed drainage have room every 2–3 days until there is no further visual or CT scan evidence of necrotic tissue or fluid. The literature shows 40%–50% of patients treated by closed drainage have residual areas of necrosis and infection and require re-operation. Continued sepsis is synonymous with undrained infection and requires reoperation.
Photometry of Saturn at large phase angles

In the present paper, the single-scattering phase function of Saturn's aerosols is determined from the vertical structure of Saturn's atmosphere, derived in a previous analysis, and Pioneer's imaging photometry of bright and dark zones on Saturn in red and blue light. The single-scattering phase function is well represented by a combination of two Henyey-Greenstein functions. Moderately forward scattering functions fit well both in red and blue light, although a definite difference between the two colors is found.
Effects of water speed and temperature on icing in thermal siphons

A numerical study has been made on the freezing in a thermal siphon immersed in water with free or forced convection. The effects of various factors on the ice column diameter are examined.
Indirect cytotoxic evaluation of dental materials

Abstract The standard for cellular biocompatibility in vitro testing is American National Standards Institute/American Dental Association Document No. 41a (1982). The standard allows for the contact testing of solid dental materials for cytotoxicity with HeLa or mouse fibroblasts (L929). The purpose of this study was to evaluate a new method of cytoxicity testing of biomaterials that allows for an economic standardized indirect cytotoxic screening of the originally dispensed material over a period of time at intervals decided by the investigator. The results show a significant difference of cytotoxicity on the basis of the material between the direct contact method and the indirect or diffusion method described.
Microfluidics for medical diagnostics and biosensors

Abstract This article reviews the recent development in microfluidics for medical diagnostics and integrations with biosensors. Diagnostic and sensing applications have been the focus of much of the development of the micro-Total-Analysis-Systems (MicroTAS), and have recently enjoyed further development in new fabrication technologies, integrations, and utilities in field- and medical-applications. The challenges for these applications have been to reduce cost, to meet the sensitivity requirements while providing throughput and speed, and to expand the repertoire of applications. This review focuses mostly on new developments in the last 5–10 years in materials development, chip architecture and integration, different sensing modes that can be used in conjunction with microfluidics, and new applications that have emerged or have been demonstrated; it also aims to point out where future research can be directed to in these areas.
Keeping Kids Safe from a Design Perspective: Ethical and Legal Guidelines for Designing a Video-Based App for Children

Educators can use video to gain invaluable information about their students. A concern is that collecting videos online can create an increased security risk for children. The purpose of this article is to provide ethical and legal guidelines for designing video-based apps for mobile devices and the web. By reviewing the literature, law, and code of ethics around designing sites that capture video of young children, we have developed a set of questions that can guide designers through the decisions that need to be considered in their plans. As an example, we describe how we applied these questions to the design of a Story Retell app, which enables students to share videos of themselves reading to gain feedback from their teachers. Although each design decision will vary across instructional contexts, these guidelines can serve as a framework for designing similar apps that collect video of children.
Intercomparison of Single-Frequency Methods for Retrieving a Vertical Rain Profile from Airborne or Spaceborne Radar Data

Abstract This paper briefly reviews several single-frequency rain profiling methods for an airborne or spaceborne radar. The authors describe the different methods from a unified point of view starting from the basic differential equation. This facilitates the comparisons between the methods and also provides a better understanding of the physical and mathematical basis of the methods. The application of several methods to airborne radar data taken during the Convective and Precipitation/Electrification Experiment is shown. Finally, the authors consider a hybrid method that provides a smooth transition between the Hitschfeld-Bordan method, which performs well at low attenuations, and the surface reference method, for which the relative error decreases with increasing path attenuation.
The priming of association test responses: Generalizing the phenomenon

Priming refers to the activation of words in a pretask and their recovery as associates on a subsequent association test. Four types of pretask were used: a list of 14 words to learn, a matrix containing the 14 words, each of which S checked when it was called off, a task of matching each of the words with a geometric figure, and an association test where S responded to each of the 14 words. The Ss were also asked to recall the words after the association test, and for certain groups recall was taken before the association test as well. Priming was obtained in all conditions, but the amount of priming did not differ significantly among conditions. This fact was taken as an indication of the generality of the priming phenomenon. Special effects of rehearsal and of association test priming were also considered.
Technical advances of pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension.

Pulmonary endarterectomy is the definitive treatment for chronic pulmonary hypertension as the result of thromboembolic disease. Although significant progress has been made over the last decade in recognition, diagnostic modalities, and treatment of this disease, chronic thromboembolic pulmonary hypertension (CTEPH) continues to be severely underdiagnosed and as a consequence pulmonary endarterectomy remains an uncommon procedure. Patients with CTEPH may present with a variety of debilitating cardiopulmonary symptoms. However, once diagnosed, there is no curative role for medical management, and surgery remains the only option. Medical management in these patients is only palliative, and surgery by means of transplantation for this type of pulmonary hypertension is an inappropriate use of resources with less than satisfactory results. In this article we describe the technical advances of pulmonary endarterectomy and the current procedure as it is performed at University of California–San Diego Medical Center.
When Do Essential Tremor Patients Develop Head Tremor? Influences of Age and Duration and Evidence of a Biological Clock

Background: Essential tremor (ET) is a chronic, progressive neurological disease. Head (neck) tremor may eventually develop in as many as 30-60% of patients, yet
Staging Resistance in Bil'in: The Performance of Violence in a Palestinian Village

Weekly confrontation between Palestinian villagers and the Israeli army in Bil'in is a ritual played out with such consistency and deliberation one cannot but note the performance on both sides. A closer look reveals a politics of oppression and a strategy of resistance that extend far beyond the massive concrete wall being built between them.
Corrections to “A Selective Feature Information Approach for Iris Image-Quality Measure” [Sep 08 572-277]

In the above titled paper (ibid., vol. 3, no. 3, pp. 572-577, Sep. 08), equation (2-11) on page 574 contains a typo. The correct equation is presented here.
Motivating creativity through a computer-mediated employee suggestion management system

This paper describes the requirements for an automated employee suggestion management system (ESMS) based on expectancy theory and computer-mediated communications. Although research has found that suggestion systems can be a useful way to obtain and utilize employees' creative ideas, effective suggestion management systems must also motivate employees to think creatively and to participate in the suggestion process. According to expectancy theory, employees are most strongly motivated to participate when they believe that they can do so successfully and when they know that their participation will result in an outcome that they value. The system proposed here addresses the requirements of expectancy theory, and the weaknesses of existing suggestion systems, by establishing a communications infrastructure and protocol similar to those used in group decision support systems. The system motivates employees to submit suggestions by providing an interactive networked forum within which employees and intereste...
Latent partition analysis

Latent partition analysis has been formulated to study the relationships between two or more partitions of the same set of items. The major structural hypothesis is that a latent partition underlies the manifest partitions; that is, it is assumed that each item belongs to a latent category and that the manifest categories are derived by dividing and combining the latent categories. We have found that by examining manifest categories it is possible to reconstruct information about the latent partition and about its relation to the manifest partitions.
Porous inorganic-organic shape memory polymers.

Thermoresponsive shape memory polymers (SMPs) are a type of stimuli-sensitive materials that switch from a temporary shape back to their permanent shape upon exposure to heat. While the majority of SMPs have been fabricated in the solid form, porous SMP foams exhibit distinct properties and are better suited for certain applications, including some in the biomedical field. Like solid SMPs, SMP foams have been restricted to a limited group of organic polymer systems. In this study, we prepared inorganic–organic SMP foams based on the photochemical cure of a macromer comprised of inorganic polydimethylsiloxane (PDMS) segments and organic poly(e-caprolactone) (PCL) segments, diacrylated PCL40-block-PDMS37-block-PCL40. To achieve tunable pore size with high interconnectivity, the SMP foams were prepared via a refined solvent-casting/particulate-leaching (SCPL) method. By varying design parameters such as degree of salt fusion, macromer concentration in the solvent and salt particle size, the SMP foams with excellent shape memory behavior and tunable pore size, pore morphology, and modulus were obtained.
Thermodynamic evolution during diffusion

The diffusion equation (continuity of matter) is generally used to predict the change of composition during mass transport. The equation may also be used to analyze the evolution of the chemical potential. Since the resulting equation is nonlinear, solutions for practical situations are difficult. It is shown that the linear equation with composition as the dependent variable can be used as a parallel equation to aid in the description of the chemical potential. Once the history of the chemical potential is determined, composition can be found for the complicated cases where the activity coefficient varies in a discontinuous manner leading to the “uphill” diffusion associated with interstitial diffusion in multicomponent systems and trapping situations.
Reticular Mandibular Gingival Ridges

This paper reports five cases of a heretofore unreported condition of the gingiva named reticular mandibular gingival ridges. Occurring in middle-aged males, macroscopically, they are bilateral ridges on the mandibular attached gingivae resembling rugae and having a reticular pattern that may be mistaken for lichen planus. Microscopically, they are formed of fibrous tissue with vessels that have a minimal perivascular infiltrate; the epithelium has extension of rete ridges. Of unknown etiology, the condition does not appear to change, is innocuous and does not require treatment.
A goal programming approach to job evaluation

Abstract Job evaluatio refers to a systematic determination of the relative values of jobs in an organization. Often, jobs are evaluated based upon subjective judgement. By considering each job to consist of certain levels of different job factors, this paper develops a goal programming model to evaluate various levels of job factors. The main constraints in such a formation are obtained by using some existing benchmark jobs. The model development and application in evaluating new jobs are illustrated by solving an example problem consisting of four factors and six levels of each factor.
On comparing restricted least squares estimators

Abstract This paper examines the conditions under which it is possible to make comparisons between restricted least squares estimators under a generalized mean square error criterion. Our results demonstrate the rather extreme limitations on such comparisons — in many cases it is not possible to compare two restricted least squares estimators using the generalized mean square error criterion.
Preliminary evaluation of tensile and stress-rupture behavior of W + 24 at. pct Re + 0.4 at. pct HfC wire

Results are presented of an evaluation of tensile properties and stress-rupture bahavior of a small-diameter W24ReHfC (W-24Re-0.4(HfC)) wire, which is considered to be an excellent reinforcing fiber candidate for a variety of metal-matrix composites. The results were compared to data of Petrasek (1972) on W4ReHfC (W-4Re-0.4(HfC)) wire. It was found that the room-temperature (RT) tensile strength of the W24ReHfC wire was about 3250 MPa, higher than that of the W4ReHfC (3160 MPa) and WHfC (2250 MPa) wires. Above 1366 K, the W4ReHfC wire had both a greater tensile strength and the stress rupture strength than the W24ReHfC wire.
An Improved Approach To Characterizing And Presenting Streak Camera Performance

The performance of a streak camera recording system is strongly linked to the technique used to amplify, detect and quantify the streaked image. At the Lawrence Livermore National Laboratory (LLNL) streak camera images have been recorded both on film and by fiber-optically coupling to charge-coupled devices (CCD's). During the development of a new process for recording these images (lens coupling the image onto a cooled CCD) the definitions of important performance characteristics such as resolution and dynamic range were re-examined. As a result of this development, these performance characteristics are now presented to the streak camera user in a more useful format than in the past. This paper describes how these techniques are used within the Laser Fusion Program at LLNL. The system resolution is presented as a modulation transfer function, including the seldom reported effects that flare and light scattering have at low spatial frequencies. Data are presented such that a user can adjust image intensifier gain and pixel averaging to optimize the useful dynamic range in any particular application.
The effects of waveform asymmetry on the offtrack capability of an MR head

When the waveform distortion in a magnetoresistive head is affected by the alignment between the sensor and the recorded track, changes in the ontrack asymmetry can produce systematic changes in the offtrack capability. A qualitative model is presented to illustrate the mechanism responsible for producing this relationship.
Considering expected utility of future bidding options in bundle purchasing with multiple auctions

This paper presents an algorithm for decision-making in multiple open ascending-price (English) auctions where the buyer needs to procure a complete bundle of complementary products. When making bidding decisions, the utility of each choice is determined by considering the buyer's expected utility of future consequential decisions. The problem is modeled as a Markov decision process (MDP), and the value iteration method of dynamic programming is used to determine the value of bidding/not bidding in each state. To ease the computational burden, three state-reducing techniques are employed. When tested against adaptations of two methods from the literature, results show that the algorithm works significantly better when sufficient information on the progress of other concurrently running auctions will be available when future bidding decisions are made.
Psychosocial manifestations of arthritis for the individual and family

A person diagnosed with arthritis is in most cases confronted with a lifelong chronic disease. Arthritis often follows an unpredictable course with an uncertain future. Patients are faced with many life changes and cannot help but respond to each new situation emotionally. Many patients claim that the mental pain and emotional turmoil caused by this chronic illness are worse than the physical pain. This article presents developmental models to enhance the health care professional's understanding of the emotional needs of the patient with arthritis.
Photostimulated Generation of Defects and Surface Reactions on a Series of Wide Band Gap Metal-Oxide Solids

The interconnection between photostimulated formation and destruction of defect centers (F- and V-type color centers) and surface photochemical reactions taking place on the surface has been examined for a series of 21 wide band gap metal-oxide specimens, which comprise insulators and semiconductors whose band-gap energies span the range from ca. 3 eV (ZnO, TiO2) to ca. 11 eV (BeO). Photostimulated post-adsorption of O2 was seen for 9 of the 21 metal oxides tested. Three of these specimens, namely scandia (Sc2O3), zirconia (ZrO2), and normal spinel (MgAl2O4), were chosen for detailed study to establish that spectral sensitization of metal oxides by UV illumination is a generally occurring phenomenon which is carried over to photostimulated adsorption of molecules and to surface photochemical reactions. Results demonstrate that irradiation into the absorption bands of the color centers of the photocolored metal oxides leads to a red shift of the spectral limit of surface photoreactions. A simple mechanism ...
Use of a push enteroscope improves ability to perform total colonoscopy in previously unsuccessful attempts at colonoscopy in adult patients.

Objective: Total colonoscopy with use of a standard adult colonoscope can be difficult in the presence of a redundant or angulated colon. It is often possible to traverse these areas with the use of a thinner, more flexible endoscope. The objective of this study was to evaluate the efficacy of completing total colonoscopy using a push enteroscope when a standard colonoscope was unsuccessful. Methods: A prospective analysis was performed for 721 consecutive colonoscopies attempted by two gastroenterologists. Those patients in whom complete colonoscopy was unsuccessful using the standard colonoscope (Olympus CF-100L) had attempts to complete colonoscopy using the enteroscope (Olympus SIF-100). The extent of each exam was recorded. Additional pathologic findings discovered by the use of the enteroscope and therapeutic interventions performed were additionally noted. Results: Colonoscopy using an enteroscope was performed in 32 patients with successful total colonoscopy in 22 patients (68.7%). Additional pathology was noted in nine patients who had successful complete colonoscopy using the enteroscope; adenomatous polyp (n = 5), adenocarcinoma (n = 1), bleeding source (n = 2), and extent of colitis (n = 1). Total colonoscopy rate using standard adult colonoscope was 93.2% (630 of 676) when cases with poor bowel preparation (n = 23) and obstructing lesions (n = 14) were excluded. When the results of successful colonoscopies with the enteroscope were included, the overall completion rate of total colonoscopy improved to 96.4% (652 of 676). Conclusion: The use of the enteroscope to help evaluate patients who have had incomplete colonoscopies with the standard colonoscope increases the diagnostic yield of colonic examination.
Paradoxical effects of exogenous norepinephrine on cold-induced thermogenesis in the rat ☆

Abstract The effect of norepinephrine (NE, 250 μg/kg IP) on thermoregulatory behavior of rats in a cold environement was tested. Norepinephrine produced an increase in operant responding for heat reward but a decrease in core temperature. Since animals compensate behaviorally for alterations in autonomic thermoregulation, this suggested that NE might inhibit cold-induced thermogenesis, an effect contrary to the expected action of this agent. A second experiment showed that NE increased oxygen consumption when rats were tested at 25°C as expected, but decreased oxygen consumption when tested at 5°C. The beta-adrenoceptor antagonist propranolol decreased oxygen consumption both at 25 and at 5°C as expected. These results suggest that the thermogenic effect of NE is highly dependent on ambient temperature.
Ileal dysgenesis presenting with anemia and growth failure

A case of ileal dysgenesis in a child presenting with anemia and chronic growth suppression, and characterized preoperatively with duodenal barium infusion and technetium pertechnetate scan is discussed.
Sequences and structures required for recombination between virus-associated RNAs

RNA recombination has been described for a number of viruses in the plant and animal kingdoms, but the mechanisms of selection of recombination sites are poorly understood. The nonrandom recombination between two subviral RNAs associated with turnip crinkle virus was used to study the requirement for specific sequences and structures in the generation of recombinant molecules. Single-base mutations that disrupted either the stem or the loop of one of the two computer-predicted stem-loop structures eliminated detectable recombinant molecules. However, recombinants were detected if compensatory mutations were generated that re-formed a stable hairpin structure. These results provide evidence for the necessity of specific structures in the formation of recombinant molecules in this system.
Adaptive reduction of intensity levels in 3D images for mutual information-based registration

Mutual information is currently one of the most widely used image similarity measures for multimodality image registration. An important step in the calculation of the mutual information of two images is the estimation of their joint histogram. Most algorithms use lateral joint histogram sizes that are smaller than the actual number of intensity levels present in the images being registered. Using a reduced joint histogram size is especially useful when registering small portions of the images to obtain local deformations in nonrigid registration algorithms, and when implementing hardware solutions for acceleration of mutual information calculation. The most commonly used method for reducing the size of the joint histogram is to perform a linear rescaling of intensity values. The main problem with this method is that image regions with similar intensity values but corresponding to distinct tissue types tend to merge, thus compromising the accuracy of registration. We present new algorithms for reducing the number of gray levels present in 3D medical images, and compare their performance with previously reported ones. The tested algorithms are classified in three categories: histogram shape preserving algorithms, entropy maximization algorithms and quantization error minimization algorithms. Results show that in CT and MRI registration the best accuracy is achieved using entropy maximization algorithms, while in PET and MRI registration the best accuracy is achieved using histogram shape preservation algorithms.
High strain-rate response and deformation mechanisms in polycrystalline Ti2AlC

Abstract Ti2AlC is a representative member of MAX phase materials, which are known to exhibit a unique combination of properties observed in conventional ceramics and metals. In this paper, experimental protocols for the high strain-rate compressive response (up to ~4700 s−1) using a Split Hopkinson Pressure Bar (SHPB) is developed. The optimized specimen geometry for Ti2AlC, derived in this work, ensures dynamic equilibrium and minimizes dispersion in the transmitted pulse. A modification of the conventional SHPB experimental set-up involves in situ high speed imaging, which facilitates identification of real strains free of macroscopic crack artifacts. Characteristics of the high strain-rate response of polycrystalline Ti2AlC, associated deformation mechanisms and micro-scale origins are presented. The results show that Ti2AlC shows significant inelastic deformation and strain softening before fracture, even at very high strain-rates. Post-fracture microstructures are analyzed to determine dominant deformation mechanisms which reveal simultaneous coexistence of kink bands and delamination, grain-pullouts and trans-granular cracks induced by high strain-rate loading. These deformation characteristics – also active under quasi-static loading, are responsible for the exceptional damage tolerance of Ti2 AlC and provide experimental evidence for high rate kink banding in MAX phases.
Fixed-structure discrete-time mixed H/sub 2//H/sub /spl infin// controller synthesis using the delta-operator

For discrete-time control, it has been shown that a difference operator formulation provides improved performance over the standard shift operator when using finite wordlength computation. This property has led to the use of the difference operator in several areas of modern multivariable control, including LQR/LQG and H/sup /spl infin//-optimal control. The discrete-time fixed-structure mixed H/sup 2//H/sup /spl infin// problem has been formulated using the shift operator (q-domain) framework using both an H/sup 2//H/sup /spl infin// norm overbound and a formulation of the exact constrained minimization problem. In both cases, the problem is nonconvex and thus requires a numerical algorithm for solution. The difference operator is applied to mixed H/sup 2//H/sup /spl infin// controller synthesis. Necessary conditions for optimal mixed H/sup 2//H/sup /spl infin// controller synthesis utilizing the difference operator are developed. Approximate solutions to these conditions are computed via a hybrid BFGS quasi-Newton/continuation algorithm, and compared with the solutions obtained from formulating the same problem in the q-domain.
Sphingolipids in the DNA damage response

Recently, sphingolipid metabolizing enzymes have emerged as important targets of many chemotherapeutics and DNA damaging agents and therefore play significant roles in mediating the physiological response of the cell to DNA damage. In this review we will highlight points of connection between the DNA damage response (DDR) and sphingolipid metabolism; specifically how certain sphingolipid enzymes are regulated in response to DNA damage and how the bioactive lipids produced by these enzymes affect cell fate.
Development of auditory temporal resolution in school-age children revealed by word recognition in continuous and interrupted noise.

Objective: The purpose of the study was to investigate the development of one aspect of auditory temporal resolution in normal-hearing school-age children with word recognition in quiet and in spectrally identical continuous and interrupted noise. Typically, listeners experience a perceptual advantage (i.e., a release from masking) in the interrupted noise relative to the continuous noise at equivalent signal-to-noise ratios (S/Ns). Any release from masking observed with children in the interrupted noise compared with the continuous noise at equivalent S/Ns could be interpreted as evidence for acquired temporal resolution ability. Differences in the amount of release from masking in the interrupted noise between children and adults could be interpreted as development of temporal resolution ability, or lack thereof, as revealed by word recognition in noise. It was hypothesized that word recognition performance would be poorer in children than adults; performance differences would be more pronounced with competition; word recognition performance would reach an asymptote to adult levels sooner in quiet than with competing stimuli; children would demonstrate better performance in the interrupted noise relative to the continuous noise (i.e., display a release from masking); and younger children would experience less release from masking compared with older children and adults (i.e., have less developed temporal resolution). Design: Eighty normal-hearing children aged 6 to 15 yr and 16 normal-hearing young adults participated. Word recognition performance with Northwestern University-Children's Perception of Speech (NU-CHIPs) stimuli was evaluated with an open-set response mode in quiet and in backgrounds of competing continuous steady-state and interrupted noise at S/Ns of 10, 0, -10, and -20 dB. Both noises were essentially identical in their spectral content and differed only in their temporal continuity. Results: Performance was better in the interrupted noise at poorer S/Ns, increased with increasing S/N, and improved with increasing age. Younger listeners were more susceptible to noise. They did not experience an equivalent perceptual advantage (i.e., a release from masking) in the interrupted noise at poorer S/Ns (i.e., <10 dB) and generally required more favorable S/Ns to perform the same as the adult participants. These trends were less pronounced with increasing age. By 8 yr of age, children's performance in quiet equated that of adult levels, but it did not do so in noise until after 11 yr of age. Conclusions: As revealed by their NU-CHIPs word recognition performance in continuous and interrupted noises, children's temporal resolving abilities improve in their early school years and reach adult performance levels after 11 yr of age. It was speculated that these changes reflect maturation in their central auditory system.