cssi/SciSciGPT-SciSciNet huggingface dataset:
Silver-Enhanced Imaging of DNA Hybridization at DNA Microarrays with Scanning Electrochemical Microscopy

The use of scanning electrochemical microscopy (SECM) to image oligodeoxynucleotide (ODN) hybridization at spots on microarrays has been demonstrated. ODN probes at a microarray surface were hybrid...
A Bode-like integral for discrete-time linear periodic systems

We present a generalization of Bode's integral formula for discrete-time linear periodic systems. It is shown that similar to the classical Bode's integral formula, the sensitivity integral for a discrete-time linear periodic system depends only on the open-loop dynamics; in particular, on the open-loop characteristic multipliers outside the unit circle in the complex plane. The integral is derived by using an asymptotic eigenvalue distribution theorem for block Toeplitz matrices. We do not require the open loop system to be stable. Further, as opposed to the existing results on Bode like integrals for unstable open loop systems, we do not require the disturbance to be Gaussian.
Efficacy of a vibratory stimulus for the relief of HIV-associated neuropathic pain

Abstract Pain related to HIV disease is frequently debilitating. Of the many pain syndromes that occur in persons with HIV, distal symmetrical polyneuropathy (DSPN) is particularly devastating. Because DSPN often responds, at best, only partially to available pharmacologic interventions, non-pharmacologic interventions need to be investigated. Vibration has been suggested to be effective for reducing pain in other populations with chronic pain. This randomized, sham-controlled, double-masked study tested the short-term efficacy of a 45-min vibration treatment for DSPN foot pain in persons infected with HIV. Vibration therapy was delivered using a portable platform foot vibrator that provided stimulation at a frequency of 60 Hz. For all patients, the control box for the vibrator emitted an audible hum and part of the control box lit up during treatment, but only patients randomized to active treatment received vibration. Pain intensity (0–10) was measured immediately prior to and after treatment. Subjects were also questioned regarding pain relief (0–100%) immediately after the treatment. The mean percentage pain relief was 61.0±33.1% (median 70.0; range 0–100) for all patients, 67.3±34.0% (median 80.0; range 0–100) for vibration patients, and 55.0±32.0% (median 60.0; range 0–100) for sham patients. No statistically significant differences were found between the vibration and sham groups with respect to percentage pain relief (Mann–Whitney test; P=0.19) or the pre- and post-treatment current-pain difference (Mann–Whitney test; P=0.92). These results underscore the necessity for control groups in studies of non-pharmacologic therapies for pain.
Evaluation of an Isolate ofMyrothecium verrucariafrom Sicklepod (Senna obtusifolia) as a Potential Mycoherbicide Agent

In greenhouse studies,Myrothecium verrucariaisolated from sicklepod (Senna obtusifolia) affected several plant species, including a number of economically important crop, ornamental, and weed species. Responses of inoculated plants to the fungus ranged from no reduction in dry weight to 100% mortality. New host responses (as indicated by mortality and/or ≥50% reductions in dry weights of inoculated plants) included: beet (Beta vulgaris), turnip (Brassica rapa), radish (Raphanus sativus), sicklepod, coffee senna (Cassia occidentalis), hemp sesbania (Sesbania exaltata), spurred anoda (Anoda cristata), and jimsonweed (Datura stramonium). Disease development in sicklepod was influenced by inoculum and surfactant concentrations, dew temperature, dew duration, and growth stage of plants when inoculated. Inoculum concentrations of 2 × 107conidia/ml plus 0.05% (w/v) surfactant resulted in approximately 95% mortality of sicklepod seedlings following a 6-h dew at 25°C. Inoculum concentrations of 8 × 107conidia/ml killed approximately 40% of sicklepod seedlings in the absence of dew. Soybean (Glycine max) plants inoculated by foliar applications of 2 × 107conidia/ml exhibited dry-weight reductions of 65–75%. However, the fungus applied as directed spray applications (8 × 107conidia/ml) to mixed plantings of sicklepod and soybean seedlings, so that the soybean plants were inoculated only on the stems and lower leaves, killed 97% of the sicklepod plants after a 6-h dew period at 25°C, with no dry-weight reduction in the soybean plants. Additional research is needed to assess the potential of the sicklepod isolate ofM. verrucariaas a mycoherbicide agent.
Upper excited-state photochemistry of DNA and nucleotides

Two sets of experiments dealing with the upper excited states of DNA are presented here. In one investigation, one-photon excitation of DNA with low intensity UV laser radiation (199.8, 217.8, and 239.5 nm) is exploited to assess damage done upon excitation to singlet states higher than the first excited singlet state. In another, the sequential excitation of DNA with 266 nm laser radiation and 532 nm photons was explored using ps laser radiation.
Parallel simulations of wireless networks with TED: radio propagation, mobility and protocols

We describe the TeD/C++ implementation of WiPPET, a parallel simulation testbed for mobile wireless networks. In this article we emphasize the techniques for modeling of radio propagation (long- and short-scale fading and interference) and protocols for integrated radio resource management in mobile wireless voice networks. The testbed includes the standards-based AMPS, NA-TDMA and GSM protocols, and several research-oriented protocol families.
Human capital and the rise of American cities, 1900–1990

Abstract We propose that cities that start out with proportionately more knowledgeable people grow faster in the long run because (a) knowledge spillovers are geographically limited to the city and (b) much knowledge is most productive in the city within which it is acquired. We found that city-aggregates and metropolitan areas with higher average levels of human capital grew faster over the 20th century. The estimated effects of human capital were large: a standard deviation increase in human capital in 1900 was associated with a 38% increase in average annual employment growth of city-aggregates over the period 1900–86. The estimated effects for metropolitan areas were smaller but still economically significant: a standard deviation increase in 1940 human capital was associated with an increase in average annual employment growth over the period 1940–90 of about 15%. Although the rise of the automobile appears to have overwhelmed the importance of human capital in cities dominated by manufacturing early on, human capital seems to have been economically more important in manufacturing cities than in non-manufacturing cities later on. Moreover, the estimated effects of human capital persisted for very long periods of time, suggesting either that adjusting to the steady state is very lengthy, or that shocks to growth are correlated with the presence of human capital.
Learning-set formation in the bottlenose dolphin

Formation of a discrimination-learning set was investigated in the Pacific bottlenose dolphin over 80 two-choice problems. Although average Trial-2 performance compared well with some primate species, performance level on later trials and on successive blocks of problems did not progressively improve. Spatial separation of stimulus cue and response locus was discussed as a possible contributor to the observed limited performance level.
Labiovelar compensation in back vowels

Various studies have revealed apparent motoric compensation between articulatory structures such as the jaw and lips which contribute to articulatory goals of vocal tract constriction. The present study, like Perkell et al. [J. Acoust. Soc. Am. 93, 2948-2961 (1993)] and Savariaux et al. [J. Acoust. Soc. Am. 98, 2428-2442 (1995)], investigates the possibility of compensation between labial protrusion and constriction and dorsovelar constriction-a relationship based on the similarity of the acoustic effects of such articulatory goals. The present study differs from these earlier studies in that it assumes an articulatory model of gestures, and it examines nonperipheral back vowels. X-ray microbeam records of American English speakers producing back vowels under various stress conditions were investigated. Results reveal systematic speaker differences in the direction of correlation between measures of labial and dorsal position. These results show that speakers differ as to whether they exhibit coupling between labial and dorsal activity in the lowering of back vowel timbre.
Fractures in Brief: Radial Head Fractures

Fractures of the radial head are common [4], constituting approximately one-third of all elbow fractures. These fractures typically occur when an axial load is applied to the forearm, causing the radial head to hit the capitellum of the humerus. The severity of these injuries runs the gamut from minimally displaced fractures needing minimal treatment to those with major displacement or comminution, requiring surgical fixation, excision, or replacement.
Reminiscence: An Independent Nursing Intervention for the Elderly

The nursing literature states that reminiscence is an independent nursing intervention for elderly clients and patients. This paper is about the use of reminiscence by nurses in all settings. Nurses have not to date built a firm knowledge base. The paper discusses the need for knowledge about the phenomenon and life review versus reminiscence. The uses of reminiscence therapy in one-to-one interaction, in the group modality, and as a research tool are all important applications of the concept. In contrast to other disciplines, reminiscence therapy, as studied by nurses, focuses on interventions. Reminiscence is a fascinating, elusive, and complex phenomenon, but although nursing textbooks tout its usefulness, the research findings are less optimistic.
A hybrid approach to software reuse

We describe a hybrid approach to software reuse in an ongoing project that addresses a challenging software engineering task. The approach is driven by an architectural design and makes use of both code components and program synthesis technology. We describe criteria that were used in choosing the reuse strategy for different parts of the application and argue that to be successful a reuse strategy must be driven by the needs of an application program instead of adapting a software development strategy around a reuse program.
Sustainable Distribution Design: Contrasting Disposable, Recyclable, and Reusable Strategies for Packaging Materials Using a Total Cost Analysis With an Illustration of Milk Distribution

Engineers, policy makers, and managers have shown increasing interest in increasing the sustainability of products over their complete lifecycles and also from the ‘cradle to grave’ or from production to the disposal of each specific product. However, a significant amount of material is disposed of in landfills rather than being reused in some form. A sizeable proportion of the products being dumped in landfills consist of packaging materials for consumable products. Technological advances in plastics, packaging, cleaning, logistics, and new environmental awareness and understanding may have altered the cost structures surrounding the lifecycle use and disposal costs of many materials and products resulting in different cost-benefit trade-offs. An explicit and well-informed economic analysis of reusing certain containers might change current practices and results in significantly less waste disposal in landfills and in less consumption of resources for manufacturing packaging materials. This work presents a method for calculating the costs associated with a complete process of implementing a system to reuse plastic containers for food products. Specifically, the different relative costs of using a container and then either disposing of it in a landfill, recycling the material, or reconditioning the container for reuse and then reusing it are compared explicitly. Specific numbers and values are calculated for the case of plastic milk bottles to demonstrate the complicated interactions and the feasibility of such a strategy.Copyright © 2010 by ASME
Numerical integration techniques for discontinuous manufactured solutions

When applying the method of manufactured solutions (MMS) on computational fluid dynamic software, determining the exact solutions and source terms for finite volume codes where the stored value is an integrated average over the control volume is non-trivial and not frequently discussed. MMS with discontinuities further complicates the problem of determining these values. In an effort to adapt the standard MMS procedure to solutions that contain discontinuities we show that Newton-Cotes and Gauss quadrature numerical integration methods exhibit high error, first order limitations. We propose a new method for determining the exact solutions and source terms on a uniform structured grid containing shock discontinuities by performing linearly and quadratically exact transformations on split cells. Transformations are performed on triangular and quadrilateral elements of a systematically divided discontinuous cell. Using a quadratic transformation in conjunction with a nine point Gauss quadrature method, a minimum of 4th order accuracy is achieved for fully general solutions and shock shapes. A linear approximation of curved shocks is also experimentally shown to be 2nd order accurate. The numerical integration method is then applied to a CFD code using simple discontinuous manufactured solutions which return consistent 1st order convergence values. The result is an important step towards being able to use MMS to verify solutions with discontinuities. This work also highlights the use of higher order numerical integration techniques for continuous and discontinuous solutions that are required for MMS on higher order finite volume codes.
The coenzyme A requirement of mammalian fatty acid synthetase: Evidence for involvement in the elongation of acyl-enzyme thioesters

Abstract We have confirmed that coenzyme A is required for rat fatty acid synthetase activity (T. C. Linn, M. J. Stark, and P. A. Srere, 1980, J. Biol. Chem. 255 , 1388–1392) . When rat liver or mammary gland fatty acid synthetase was assayed in the presence of a CoA-scavenging system such as ATP citrate lyase, almost complete inhibition of fatty acid synthesis was observed. The inhibition was reversed by addition of CoA or pantetheine, but not by addition of N -acetylcysteamine or other thiols. In the absence of CoA, the rate of elongation of acyl moieties on both native fatty acid synthetase and fatty acid synthetase lacking the chain-terminating thioesterase I component (trypsinized fatty acid synthetase) was reduced 100-fold. All of the palmitate synthesized slowly by the CoA-depleted native multienzyme was released, by the thioesterase I component, as the free fatty acid; only shorter-chainlength acyl moieties remained bound to the enzyme. The acyl- S -multienzyme thioesters formed by the trypsinized fatty acid synthetase in the absence of CoA contained saturated moieties of chain length C 6 -C 16 ; addition of CoA promoted elongation of the acyl- S -multienzyme thioesters without release from the enzyme. The transfer of acetyl and malonyl moieties from CoA to the multienzyme, the reduction of S -acetoacetyl- N -acetylcysteamine and S -crotonyl- N -acetylcysteamine, and the dehydration of S -β-hydroxybutyryl- N -acetylcysteamine, reactions catalyzed by the fatty acid synthetase, were not dependent on the presence of CoA. The hydrolysis of acyl- S -multienzyme catalyzed by thioesterase I, the resident chain-terminating component of the fatty acid synthetase, and thioesterase II, a monofunctional mammary gland chain-terminating enzyme, was also independent of CoA availability as was hydrolysis of an acyl- S -pantetheine pentapeptide isolated from the multienzyme. On the basis of these observations we conclude that CoA is required for the elongation of acyl moieties on the fatty acid synthetase but not for their release from the multienzyme.
Effects of operating conditions on internal resistances in enzyme fuel cells studied via electrochemical impedance spectroscopy

Enzyme fuel cells (EFCs) offer some advantages over traditional precious-metal-catalyzed fuel cells, such as polymer electrolyte membrane fuel cells (PEMFCs). However, EFCs exhibit far less power output than PEMFCs and have relatively short life spans before materials must be replaced. In this work, electrochemical impedance spectroscopy (EIS) is used to analyze the internal resistances throughout the EFC at a variety of operating conditions. EIS analysis is focused primarily on the resistances of the anode, solution/membrane, and cathode. Increased enzyme loading results in improved power output and reductions in internal resistance. Conditions are identified for which enzyme loading does not limit the EFC performance. EIS experiments are also reported for EFCs operated continuously for 2 days; power output declines sharply over time, while all internal resistances increase. Drying of the cathode and enzyme/mediator degradation are believed to have contributed to this behavior. Finally, experiments are performed at varying air-humidification temperatures. Little effect on internal resistances or power output is observed. However, it is anticipated that increased air humidification can improve longevity by delivering more water to the cathode. Improvements to the enzymatic cathode are needed for EFC development. These improvements need to focus on improving transport rather than increasing enzyme loading.
1.1.2 The Missing Link in Systems Engineering

This paper explores a methodology of integrating the Manufacturing Process Design and Prove-out into a Systems Engineering Process. The methodology include Key Product Characteristics (KPCs) as well as Failure Modes and Effects Analyses (FMEAs). The paper provides examples and insights from the author's implementation on a presently ongoing design effort.
Relation between language comprehension and cognitive functioning in persons with mental retardation

Research on the relation between language comprehension and cognitive functioning in persons with mental retardation is reviewed. The purpose is to evaluate the validity of the clinical practice of cognitive referencing. In cognitive referencing, an individual is considered to be a good candidate for (i.e., likely to benefit from) entry into a remedial language program only if he or she displays a mental age in advance of his or her language age. The studies reviewed concern: (a) the relation between various aspects of language comprehension (e.g., pragmatic, syntactic) and mental age, (b) the relation between different cognitive skills (e.g., sequential analysis, short term memory) and language comprehension, (c) the stability of the relation between language comprehension and cognition over development, and (d) whether remedial language services can lead to levels of comprehension that exceed mental age expectations. The evidence suggests that the theoretical assumptions underlying cognitive referencing are incorrect, with the result being that many persons with mental retardation who could benefit from remedial language services may not receive those services.
Comminution of solids caused by kinetic energy of high shear strain rate, with implications for impact, shock, and shale fracturing

Although there exists a vast literature on the dynamic comminution or fragmentation of rocks, concrete, metals, and ceramics, none of the known models suffices for macroscopic dynamic finite element analysis. This paper outlines the basic idea of the macroscopic model. Unlike static fracture, in which the driving force is the release of strain energy, here the essential idea is that the driving force of comminution under high-rate compression is the release of the local kinetic energy of shear strain rate. The density of this energy at strain rates >1,000/s is found to exceed the maximum possible strain energy density by orders of magnitude, making the strain energy irrelevant. It is shown that particle size is proportional to the −2/3 power of the shear strain rate and the 2/3 power of the interface fracture energy or interface shear stress, and that the comminution process is macroscopically equivalent to an apparent shear viscosity that is proportional (at constant interface stress) to the −1/3 power of this rate. A dimensionless indicator of the comminution intensity is formulated. The theory was inspired by noting that the local kinetic energy of shear strain rate plays a role analogous to the local kinetic energy of eddies in turbulent flow.
Young African American Males: Barriers to Access to Health Care

African American males continue to experience an unacceptable and disproportionate number of health disparities when compared with other racial and ethnic groups. Young African American males can expect to live the least amount of time when compared to any other ethnic minority or racial sub-group. Understanding the obstacles and barriers that impede access to health care and wellness services among young African American males is essential to begin the process of decreasing health disparities. The goal of this qualitative study was to explore and identify the barriers experienced by young African American males in accessing health care services while also creating a rare opportunity to give voice to young African American males. The study results indicate that young African American males have multiple perceptions of barriers to health care services. Their perceptions fell into three categories: the negative impact of environment or community, lack of finances or no insurance, and distrust of medical pra...
Maternal diabetes and neonatal macrosomia. III. Neonatal body water estimates

Body water estimates were obtained within 12 h of birth in 52 infants of non-diabetic mothers and 61 infants of diabetic mothers. Neonates were grouped as normally-grown or macrosomic. Total body water and extracellular water were estimated from antipyrine space and corrected bromide space, respectively. Intracellular water was assumed to be the difference between total and extracellular water. Infants of diabetic mothers, whether normally-grown or macrosomic, had markedly less mean total body water than normally-grown neonates of non-diabetic mothers. No effect of neonatal macrosomia or maternal diabetes on extracellular and intracellular water estimates could be detected with the techniques used. It is suggested that changes in total body water occur as a result of excessive fat accretion during fetal life.
CloudChecker: An imperative framework for cloud configuration management

Cloud computing became one of the major research areas recently. The interest in cloud computing increases day by day because of the features provided by cloud providers. Pay-as-you-go is one of these features that attract customers to adopt this idea. Another feature is providing different levels of services to the customers; Software, Platform, and Infrastructure as a Service are the major services provided by clouds.
Ethnopolitical Parties and Development Cooperation The Case of Belgium

What are the effects of ethnopolitical cleavages within the state on its foreign policy? This question has not received much attention in the literature. The coalition participation of ethnopolitical parties in Belgium offers a unique opportunity to empirically evaluate the implications of ethnic politics for a state's foreign policy. Twice, nationalist politicians held the post of minister of development cooperation. The rhetoric and policy behavior of these individuals is compared with that of a “mainstream” minister of development cooperation. The article derives its expectations from the literatures on foreign assistance donor motivation, national identity, consociationalism, and coalition theory. The findings suggest that there is no statistically significant difference between nationalist and mainstream ministers of development cooperation. A potential explanation for this finding is advanced.
The application of program verification techniques to hardware verification

The growing complexity of machine designs and costs of engineering changes are increasing the demand for tools and methods to detect errors earlier in the hardware development cycle. Because of similar concerns in the development of software there has been a great deal of work on methods for proving that a program satisfies a given specification. This paper examines one such program verification technique, based on the notion of symbolic execution, and then explores its application to the problem of establishing the correct behavior of a piece of hardware.
Involvement of the pineal gland and melatonin in murine analgesia

Abstract The data presented herein suggest that an intact pineal gland is required for the expression of the increased nocturnal sensitivity to morphine observed in mice. We report that the day/night rhythm of morphine analgesia was not evident in pinealectomized mice. Further, mice treated with melatonin exhibited a dose-related analgesic response. The decrease in sensitivity to pain was not observed in animals in which melatonin administration was followed by the opiate antagonist, naloxone. These data suggest that information derived from environmental lighting regulates sensitivity to pain via the pineal gland hormone melatonin, which is released and acts upon other areas of the CNS.
Therapeutic choices in the treatment of acute community-acquired bacterial rhinosinusitis.

BackgroundAcute bacterial rhinosinusitis (ABRS) is a common medical problem affecting a large percentage of the population. The disease will most often follow a viral upper respiratory tract infection.MethodsAppropriately diagnosed, ABRS is best treated with antibiotics, but other medications may play a role in some circumstances. Increasing antibiotic resistance to the common bacteria causing ABRS has occurred in the past 20 years, driven largely by inappropriate or unnecessary antibiotic use.ResultsThere are many antibiotics available that may be used for the treatment of ABRS. The selection of the best antibiotic option is determined by evaluating a number of factors, with the potential antibiotic resistance being an important consideration.ConclusionThis article reviews current recommendations for the antibiotic treatment of ABRS.
Postpartum Death with Maternal Congenital Heart Disease

Four women, with congenital heart disease, who died following parturition are presented. All had advanced pulmonary arterial lesions before delivery. In the intrapartum or early postpartum period widespread fibrin and platelet thrombi occluded already narrowed pulmonary arterial channels increasing right-to-left cardiac shunts. The etiology of the preterminal thrombotic disorder has not been established in any of the cases.
Marketing and Retention Strategies for Adult Degree Programs.

Four marketing strategies are critical to the success of adult degree programs: integrating marketing, knowing your students (research), shaping programs and services for adults, and staying the course (retention).
Thermodynamics of electron transfer in oxygenic photosynthetic reaction centers: volume change, enthalpy, and entropy of electron-transfer reactions in manganese-depleted photosystem II core complexes.

We have previously reported the thermodynamic data of electron transfer in photosystem I using pulsed time-resolved photoacoustics [Hou et al. (2001) Biochemistry 40, 7109−7116]. In the present work, using preparations of purified manganese-depleted photosystem II (PS II) core complexes from Synechocystis sp. PCC 6803, we have measured the ΔV, ΔH, and estimated TΔS of electron transfer on the time scale of 1 μs. At pH 6.0, the volume contraction of PS II was determined to be −9 ± 1 A3. The thermal efficiency was found to be 52 ± 5%, which corresponds to an enthalpy change of −0.9 ± 0.1 eV for the formation of the state P680+QA- from P680*. An unexpected volume expansion on pulse saturation of PS II was observed, which is reversible in the dark. At pH 9.0, the volume contraction, the thermal efficiency, and the enthalpy change were −3.4 ± 0.5 A3, 37 ± 7%, and −1.15 ± 0.13 eV, respectively. The ΔV of PS II, smaller than that of PS I and bacterial centers, is assigned to electrostriction and analyzed using t...
The effects of calcitonin in hypercalcemia in patients with malignancy

Porcine calcitonin (PC) is a potent serum calcium lowering agent in human subjects with hypercalcemia. Hypercalcemia in patients with neoplasia was temporarily corrected with these agents until more definitive measures were instituted to control their neoplastic disease. Of the 10 hypercalcemic patients administered calcitonin I.M. every 4–6 hours or as a 24-hour I.V. infusion, 9 who were treated with PC experienced depressed serum calcium levels. The average change in serum calcium was –2.9 mg/100 ml. The dose range of calcitonin, 2–8 Medical Research Council Units (MRUC)/kg disclosed no adverse systemic or hypersensitive reactions to the drug. This study further confirmed that calcitonin affects both kidney and bone. These findings suggest that calcitonin has great potential as an effective therapeutic agent in the treatment of hypercalcemia.
Economic Aspects of General Anaesthesia

Proper economic evaluation involves comparative analysis of alternative courses of action in terms of both costs and outcome. This is difficult for general anaesthesia as there are few alternatives and measurement of outcome is difficult to define. All that is generally available is a cost description of different anaesthetic techniques. This article outlines the choice of drugs, breathing systems and ventilatory pattern available to the anaesthetist, and compares regional with general anaesthesia. For each technique the cost and advantages/disadvantages are outlined. There is a discussion of some wider issues involved together with their implications: the abandonment of cyclopropane and nitrous oxide; equipment costs and recommendations by the Association of Anaesthetists of Great Britain and Ireland; staffing levels; legal aspects and the increase in day surgery. The limitation of cost-effectiveness analysis of general anaesthesia is outlined.
Varying DNA Base-Pair Size in Subangstrom Increments: Evidence for a Loose, Not Large, Active Site in Low-Fidelity Dpo4 Polymerase

We describe the first systematic test of steric effects in the active site of a Y-family DNA polymerase, Dpo4. It has been hypothesized that low-fidelity repair polymerases in this family more readily accept damaged or mismatched base pairs because of a sterically more open active site, which might place lower geometric constraints on the incipient pair. We have tested the origin of low fidelity by use of five nonpolar thymidine analogues that vary in size by a total of 1.0 A over the series. The efficiency and fidelity of base-pair synthesis was measured by steady-state kinetics for single-nucleotide insertions. Analogues were examined both as incoming deoxynucleoside triphosphate (dNTP) derivatives and as template bases. The results showed that Dpo4 preferred to pair the thymidine shape mimics with adenine and, surprisingly, the preferred size was at the center of the range, the same optimum size as recently found for the high-fidelity Klenow fragment (Kf) of Escherichia coli DNA Pol I. However, the siz...
Effect of Rapid Pacing and T-Wave Scanning on the Relation Between the Defibrillation and Upper-Limit-of-Vulnerability Dose-Response Curves

Background The critical-point and upper-limit-of-vulnerability (ULV) hypotheses predict that the ULV dose-response curve should be steeper and to the right of the defibrillation (DF) curve. Yet, some recent experimental data contradict this prediction. Two studies are presented that test two explanations for the contradiction: (1) Testing at a single point in the T wave underestimates the ULV dose-response curve and (2) ULV testing at normal heart rates does not mimic the mechanical or electrical state of the heart in ventricular fibrillation (VF). Methods and Results A nonthoracotomy lead system with a biphasic waveform was used throughout. In eight dogs, the dose-response curve widths (a measure of steepness) were compared between DF data and ULV data gathered at the peak (ULV PK ), middownslope (ULV DWN ), midupslope (ULV UP ), and all times (scanning or ULV SCN ) in the T wave. In another eight dogs, ULV data (ULV RAP ) were gathered by scanning the T wave after 15 rapidly paced beats (166- to 198-ms pacing interval). The rapid pacing interval was chosen to more closely mimic the hemodynamics and activation rate of early VF. ULV data (ULV STD ) at normal heart rates were gathered for all animals. In the first study, scanning significantly reduced the ULV curve width (ULV SCN , 63.5±29.7 V; ULV PK , 81.9±45.2 V; ULV DWN , 116±36.5 V; DF, 105±22.0 V; P 80 SCN , 410±62.6 V; ULV 80 PK , 266±35.3 V; ULV 80 DWN , 355±80.4 V; DF 80 , 427±60.9 V; P RAP curve was shifted dramatically to the right, the average ULV 50 RAP being greater than the average DF 90 . Furthermore, 92% of the ULV RAP VF inductions occurred between 10 ms before and 50 ms after the peak of the T wave, suggesting that scanning of the entire T wave may not be necessary. Conclusions With a single rapidly paced ULV sequence with limited T-wave scanning, it may be possible to estimate highly effective defibrillation doses with few VF episodes and high-voltage stimuli.
The Reputations of American Medical Schools

This study is one of a larger inquiry into organizational stratification. About U.S. medical schools it asks: How does a sample of full-time clinical and basic science medical school faculty rank 94 medical schools as to quality of faculty and effectiveness of instruction? And: What are the structural correlates of such rankings? The resulting rank order takes on significance as it affects recruitment and placement of students and faculty. Measures of aggrandizement (inflated estimates of worth by insiders) are estimated. Characteristics of medical schools that correlate with perceived quality are: research and publication, eminence of faculty, training and research grants available, size of full-time faculty, and perceived effectiveness of training. While the data support the view that reputation stems from functionally appropriate performance, there is some evidence of a ceiling effect (Harvard) and a halo effect for schools affiliated with universities having national reputations. Regional location is positively associated with perceived reputation in the North and West, negatively in the South. Caveats are entered about interpreting the data. There is now a history spanning almost 50 years of studies that attempt to measure the quality of graduate departments of Arts and Sciences in the United States. The earliest assessment was by Raymond M. Hughes; three decades later a study was made by Hayward Keniston, followed by two American Council on Education studies, by Allan M. Cartter, and by Kenneth D. Roose and Charles J. Andersen.' The last two studies reported rankings for engineering departments, but not for other professional schools. Very little previous work has been done on the reputations, or comparative perceived quality, of professional schools generally, and medical schools specifically.2 This paper reports findings of a study designed to examine the reputational standings of American medical schools as assessed by the community of physicians and scientists who work in them.3 While reputation should not be equated with quality, it also should not be dismissed as an insignificant part of the social reality of the medical community.4 Reputation makes a difference because it has multiple consequences for students, for faculty members, and for medical schools. Students are concerned with the reputation of medical schools when they elect to apply to some rather than others. They are aware that the reputation of their alma mater has an impact on their subsequent career mobility; they perceive the medical school as a first, but critical stepping stone in the medical career, opening or closing future opportunities. *This study was supported by a grant from the National Science Foundation to the Columbia University Program in the Sociology of Science, NSF-SOC72-95326; by the Center for Advanced Study in the Behavioral Sciences, where the first author was a Fellow in 1975-76; and by a Guggenheim Fellowship, held by the first author in 1975-76. We thank Bernard Barber, Peter M. Blau, Stephen Cole, and Robert K. Merton for their helpful comments on an earlier draft of this paper.
Are aggressive treatment strategies less cost-effective for older patients? The case of ventilator support and aggressive care for patients with acute respiratory failure.

OBJECTIVES: A common assumption is that life-sustaining treatments are much less cost-effective for older patients than for younger patients. We estimated the incremental cost-effectiveness of providing mechanical ventilation and intensive care for patients of various ages who had acute respiratory failure. DESIGN: Retrospective analysis of data on acute respiratory failure from Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT). SETTING: Acute hospital. PARTICIPANTS: 1,005 with acute respiratory failure; 963 received ventilator support and 42 had ventilator support withheld. MEASUREMENTS: We studied 1,005 patients enrolled in a five-center study of seriously ill patients (SUPPORT) with acute respiratory failure (pneumonia or acute respiratory distress syndrome and an Acute Physiology Score ≥10) requiring ventilator support. For cost-effectiveness analyses, we estimated life expectancy based on long-term follow-up of SUPPORT patients and estimated utilities (quality-of-life weights) using time-tradeoff questions. We used hospital fiscal data and Medicare data to estimate healthcare costs. We divided patients into three age groups ( 50% probability of surviving at least 2 months (low-risk group). RESULTS: Of the 963 patients who received ventilator support, 44% were female; 48% survived 6 months; and the median (25th, 75th percentile) age was 63 (46, 75) years. For the 42 patients for whom ventilator support was withheld, the median survival was 3 days. For low-risk patients (>50% estimated 2-month survival), the incremental cost (1998 dollars) per quality-adjusted life-year (QALY) saved by providing ventilator support and aggressive care increased across the three age groups ($32,000 for patients age <65, $44,000 for those age 65-74, and $46,000 for those age ≥75). For high-risk patients, the incremental cost-effectiveness was much less favorable and was least favorable for younger patients ($130,000 for patients age <65, $100,000 for those age 65-74, and $96,000 for those age ≥75). When we varied our assumptions from 50% to 200% of our baseline estimates in sensitivity analyses, results were most sensitive to the costs of the index hospitalization. CONCLUSIONS: For patients with relatively good short-term prognoses, we found that ventilator support and aggressive care were economically worthwhile, even for patients 75 years and older. For patients with poor short-term prognoses, ventilator support and aggressive care were much less cost-effective for adults of all ages.
Preparation and characterization of spray-dried oxidized cellulose microparticles.

The goal of this study was to investigate the feasibility of spray drying to produce microparticles of oxidized cellulose (OC), a biocompatible and bioresorbable polymer. OCs containing 7, 13, and 20 wt% carboxylic groups were converted into stable aqueous dispersions and then spray dried using a Yamoto G-32 spray dryer, equipped with a standard fluid nozzle with an orifice of 406 μm. The following operating conditions were investigated: inlet temperature 140, 170, and 190°C; feed rate 3, 6, and 9 mL / min; and atomization air pressure 0.5, 1, and 1.5 kg f/cm2. The amounts of OC used in feed were 1, 2.5, and 5%. OC microparticles produced under these conditions were shrunken spheres, ranging in size between 0.98 ± 0.47 and 2.05 ± 0.98 μm. The different operating conditions used had no significant effect on the size and shape of particles. The use of a water-soluble plasticizer (glycerin, polyethylene glycol 400, or polyethylene glycol 6000) in the dispersion yielded microparticles with a good sphericity a...
Intercalibration of analyses of recently biosynthesized hydrocarbons and petroleum hydrocarbons in marine lipids.

The evaluation of the extent and seriousness of petroleum contamination in the marine environment requires the ef forts of many investigators. There are no adequate standardized methods for determining the levels of petroleum contamination in marine samples. Thus, i t w i l l be necessary, i n i t i a l l y , to compare resul ts of analyses in d i f ferent laboratories often obtained with d i f ferent analytical procedures. We have conducted an in te rca l i bration exercise to determine the accuracy and precision of hydrocarbon analyses.
Automated methods for estimation of sperm flagellar bending parameters

Parameters to describe flagellar bending patterns can be obtained by a microcomputer procedure that uses a set of parameters to synthesize model bending patterns, compares the model bending patterns with digitized and filtered data from flagellar photographs, and uses the Simplex method to vary the parameters until a solution with minimum root mean square differences between the model and the data is found. Parameters for Chlamydomonas bending patterns have been obtained from comparison of shear angle curves for the model and the data. To avoid the determination of the orientation of the basal end of the flagellum, which is required for calculation of shear angles, parameters for sperm flagella have been obtained by comparison of curves of curvature as a function of length for the model and for the data. A constant curvature model, modified from that originally used for Chlamydomonas flagella, has been used for obtaining parameters from sperm flagella, but the methods can be applied using other models for synthesizing the model bending patterns.
Stress induces alteration of esophageal pressures in healthy volunteers and non-cardiac chest pain patients

The present study was designed to explore the relationship between psychological stress and esophageal motility disorders. Nineteen non-cardiac chest pain patients (10 with the nutcracker esophagus and nine with normal baseline manometry) and 20 healthy control subjects were administered two acute stressors: intermittent bursts of white noise and difficult cognitive problems. The results indicated that the esophageal contraction amplitudes and levels of anxiety-related behaviors of non-cardiac chest pain patients and control subjects were significantly greater during the stressors than during baseline periods. All patients demonstrated significantly greater (P less than 0.01) increases in contraction amplitude and anxiety-related behavior during cognitive problems than during the noise stressor. The nutcracker esophagus patients showed a greater increase in contraction amplitude during the problems (23.50 +/- 9.42 mm Hg, X +/- SE) than control subjects (P less than 0.01), while the amplitude changes of chest pain patients with normal baseline manometry were not significantly greater than that of control subjects (9.00 +/- 1.91 mm Hg). The present results identified an increase in contraction amplitude as the primary esophageal response to stress. The possible interaction of esophageal contraction abnormalities, psychological stress, and the perception of chest pain is discussed.
Xylem heterochrony: an unappreciated key to angiosperm origin and diversifications.

All angiosperms can be arranged along a spectrum from a preponderance of juvenile traits (cambial activity lost) to one of nearly all adult characters (cambium maximally active, mature patterns realized rapidly early in ontogeny). Angiosperms are unique among seed plants in the width of this spectrum. Xylem patterns are considered here to be indicative of contemporary function, not relictual. Nevertheless, most families of early-divergent angiosperms exhibit paedomorphic xylem structure, a circumstance that is most plausibly explained by the concept that early angiosperms had sympodial growth forms featuring limited accumulation of secondary xylem. Sympodial habits have been retained in various ways not only in early-divergent angiosperms, but also among eudicots in Ranunculales. The early angiosperm vessel, relatively marginal in conductive abilities, was improved in various ways, with concurrent redesign of parenchyma and fibre systems to enhance conductive, storage and mechanical capabilities. Flexibility in degree of cambial activity and kinds of juvenile/adult expressions has been basic to diversification in eudicots as a whole. Sympodial growth that lacks cambium, such as in monocots, provides advantages by various features, such as organographic compartmentalization of tracheid and vessel types. Woody monopodial eudicots were able to diversify as a result of production of new solutions to embolism prevention and conductive efficiency, particularly in vessel design, but also in parenchyma histology. Criteria for paedomorphosis in wood include slow decrease in length of fusiform cambial initials, predominance of procumbent ray cells and lesser degrees of cambial activity. Retention of ancestral features in primary xylem (the ‘refugium’ effect) is, in effect, a sort of inverse evidence of acceleration of adult patterns in later formed xylem. Xylem heterochrony is analysed not only for all key groups of angiosperms (including monocots), but also for different growth forms, such as lianas, annuals, various types of perennials, rosette trees and stem succulents. Xylary phenomena that potentially could be confused with heterochrony are discussed. Heterochronous xylem features seem at least as important as other often cited factors (pollination biology) because various degrees of paedomorphic xylem are found in so many growth forms that relate in xylary terms to ecological sites. Xylem heterochrony can probably be accessed during evolution by relatively simple gene changes in a wide range of angiosperms and thus represents a current as well as a past source of variation upon which diversification was based. Results discussed here are compatible with both current molecular-based phylogenetic analyses and all recent physiological work on conduction in xylem and thus represent an integration of these fields. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161, 26–65.
On the dynamics of a beam with switching crack and damaged boundaries

AbstractThe local equivalent linear stiffness method (LELSM), which has previously been found to be efficient in predicting themodal behavior of nonlinear structural dynamic systems with cubic and dead-zone nonlinearities, is applied to a beamwith a switching crack where the crack is modeled as a nonsmooth (clearance) nonlinearity. In addition, the LELSM is alsoapplied for the boundary damage of the beam where the damage is modeled via smooth (cubic) nonlinearity, while a newtechnique for finding the global equivalent bilinear stiffness matrix (GEBSM) is introduced here to be applied to thesystems with clearance nonlinearity or switching stiffness. As a result, the GEBSM of the system of concern is formulatedbased on the approximated analytical values of the bilinear frequencies of the system. For a system with mixed clearanceand cubic nonlinearities, the GEBSM is found first for the clearance nonlinearity, and then the LELSM is subsequentlyapplied to update the GEBSM for finding the global equivalent linear stiffness matrix (GELSM) of the system. It is foundthat the GEBSM and GELSM modes, for which no a priori simulation is required, closely approximate the correspondingproper orthogonal modes for either a vanishing clearance or a small nonvanishing clearance.KeywordsLocal equivalent linear stiffness, model order reduction, nonlinear dynamic systems, proper orthogonal decomposition,smooth nonlinearity