cssi/SciSciGPT-SciSciNet huggingface dataset:
Histologic findings in specimens obtained by percutaneous directional coronary atherectomy

Abstract Percutaneous directional coronary atherectomy is a second-generation, catheter-based technique for the treatment of coronary artery disease that provides a unique opportunity to study tissue obtained from coronary artery stenoses. We reviewed the histologic finding in 131 coronary atherectomy specimens from 116 patients, including 79 primary lesions and 52 restenosis lesions that developed after a prior coronary intervention. Although atherosclerotic plaque was seen in 95% of cases, an important observation was the finding of deep arterial wall components in the majority of patients, including media in 61% and adventitia in 31%. Despite the relatively common finding of deep wall components, this was not associated with acute clinical complications. Intimal hyperplasia was seen in 64% of cases, including 96% of restenosis lesions. However, intimal hyperplasia was also seen in 45% of primary lesions. The intimal hyperplasia in primary and restenosis lesions was histologically identical and was characterized by cells that showed staining for vimentin and muscle-specific actin, consistent with a myogenous and/or myofibroblastic phenotype. Restenosis was seen in 29 of 94 lesions (31%) with angiographic follow-up an average of 6.3 months after atherectomy. The risk of restenosis was not significantly related to the vessel treated, the nature of the lesion treated (ie, primary v restenosis lesion), or any of the histologic features evaluated. In conclusion, (1) deep arterial wall components are commonly observed in coronary atherectomy specimens without acute complications and (2) intimal hyperplasia is a sensitive, but not specific, marker for restenosis lesions.
Multiple-antenna microwave ablation: analysis of non-parallel antenna implants

Microwave ablation is a minimally invasive modality increasingly being used for thermal treatment of cancer in various organs. During ablation procedures, treatment planning is typically restricted to vendor specifications of expected ablation zone volumes based on experiments in unperfused ex vivo tissues, presuming parallel insertion of antennas. However, parallel antenna implants are not always clinically possible due to the restricted control of flexible antennas and presence of intervening organs. This paper aims to quantify the effect of non-parallel antenna implants on the ablation volume. 3D electromagnetic-bioheat transfer models were implemented to analyze ablation zone profiles created by dual antenna arrays. Parallel and non-parallel implants spaced 10-25 mm with antenna tips deviated to create converging or diverging configurations were analyzed. Volumetric Dice Similarity Coefficients (DSC) were calculated to compare ablation zone volumes for parallel and non-parallel configuration. Antenna tip displacements of 3 mm/antenna yielded an average DSC of 0.78. Tip displacements of 5 mm/antenna yielded a DSC of 0.78 and 0.64 for 15 mm and 20 mm antenna spacing, respectively. For ablation with dipole antennas as the frequency of operation decreases from 2.45 GHz to 915 MHz the similarity between the ablation zones for parallel and angled cases increased significantly. In conclusion, ablation volumes with non-parallel antenna implants may differ significantly from the parallel configuration. Patient-specific treatment planning tools may provide more accurate predictions of 3D-ablation volumes based on imaging data of actual implanted antenna configurations. Methods to compare ablation zone volumes incorporating uncertainty in antenna positions and experimental results to validate the numerical modelling are also presented.
The Management of Common Infections in Ambulatory Children

Antimicrobial therapy of infection in ambulatory children remains the cornerstone of the pediatrician's practice. Despite a cornucopia of newer antimicrobial agents, the older "tried and true" drugs continue to be favored based on their history of effectiveness, lack of toxicity, and low price. It also is clear that the widespread use of antimicrobial agents has contributed to the development of resistance. We must reevaluate our antimicrobial use so that we only treat infections likely to benefit from antimicrobials. Better diagnostic techniques should be developed for rapid and accurate identification of pathogens. Finally, alternative therapeutic strategies should be investigated, such as shorter courses of treatment or use of vaccines, to lessen the selective pressure on the microbial flora. To fail to meet this challenge will mean the more rapid transition into the "postantibiotic era".
CNV-ROC

Display Omitted Chromosomal microarrays (CMAs) are important research and diagnostic tools.CNV-ROC is a software tool that can aid in the evaluation of CMA platforms.CNV-ROC uses a per-probe approach for comparison of copy number variants (CNVs).CNV-ROC calculates genome-wide true and false positive and negative results.CNV-ROC can use both unique and common, polymorphic CNVs. Chromosomal microarrays (CMAs) are routinely used in both research and clinical laboratories; yet, little attention has been given to the estimation of genome-wide true and false negatives during the assessment of these assays and how such information could be used to calibrate various algorithmic metrics to improve performance. Low-throughput, locus-specific methods such as fluorescence in situ hybridization (FISH), quantitative PCR (qPCR), or multiplex ligation-dependent probe amplification (MLPA) preclude rigorous calibration of various metrics used by copy number variant (CNV) detection algorithms. To aid this task, we have established a comparative methodology, CNV-ROC, which is capable of performing a high throughput, low cost, analysis of CMAs that takes into consideration genome-wide true and false negatives. CNV-ROC uses a higher resolution microarray to confirm calls from a lower resolution microarray and provides for a true measure of genome-wide performance metrics at the resolution offered by microarray testing. CNV-ROC also provides for a very precise comparison of CNV calls between two microarray platforms without the need to establish an arbitrary degree of overlap. Comparison of CNVs across microarrays is done on a per-probe basis and receiver operator characteristic (ROC) analysis is used to calibrate algorithmic metrics, such as log2 ratio threshold, to enhance CNV calling performance. CNV-ROC addresses a critical and consistently overlooked aspect of analytical assessments of genome-wide techniques like CMAs which is the measurement and use of genome-wide true and false negative data for the calculation of performance metrics and comparison of CNV profiles between different microarray experiments.
Motivational Factors Affecting Advanced Literacy Learning of Community College Students

This article explores the possible intrinsic and extrinsic motivational factors that community college students may bring with them into the classroom. It examines how these motivational factors affect students' learning inside and outside the community college classroom walls. The motivational factors such as mastery, self-determination, belongingness, and social responsibility that drive first language learners to achieve a level of advanced literacy is an important avenue of exploration. Such exploration helps develop an understanding of many of the problems related to developing highly literate community college students. By gaining a stronger understanding of what motivates our students, especially what motivates them outside of the classroom, both community college leaders and instructors may be better equipped to provide appropriate environmental and pedagogical opportunities for literacy learning.
Light output and radiation damage in a lead tungstate crystal

The optical absorption, light output and effects of radiation damage have been studied in a 2.2 {times} 2.2 {times} 12.8 cm{sup 3} crystal of lead tungstate. The crystal exhibits a longitudinal attenuation length which varies from roughly 13 cm to 1.5 m over the region where the scintillation emission occurs (400--800 nm). The light yield produces approximately 10 photoelectrons per MeV on a photomultiplier tube with a bialkali photocathode. The scintillation and light transmission properties of the crystal were characterized before and after exposure to 1 Mrad of {sup 60}CO gamma rays. Significant radiation induced optical absorption was observed in this crystal, along with a considerable amount of phosphorescence after irradiation. Partial spontaneous recovery from the damage occurred at room temperature, and it was possible to induce additional recovery by optical bleaching.
An artificial neural network ensemble to predict disposition and length of stay in children presenting with bronchiolitis.

Background: Artificial neural networks apply complex non-linear functions to pattern recognition problems. An ensemble is a ‘committee’ of neural networks that usually outperforms single neural networks. Bronchiolitis is a common manifestation of viral lower respiratory tract infection in infants and toddlers. Objective: To train artificial neural network ensembles to predict the disposition and length of stay in children presenting to the Emergency Department with bronchiolitis. Methods: A specifically constructed database of 119 episodes of bronchiolitis was used to train, validate, and test a neural network ensemble. We used EasyNN 7.0 on a 200 Mhz pentium PC with a maths co-processor. The ensemble of neural networks constructed was subjected to fivefold validation. Comparison with actual and predicted dispositions was measured using the kappa statistic for disposition and the Kaplan–Meier estimations and log rank test for predictions of length of stay. Results: The neural network ensembles correctly predicted disposition in 81% (range 75–90%) of test cases. When compared with actual disposition the neural network performed similarly to a logistic regression model and significantly better than various ‘dumb machine’ strategies with which we compared it. The prediction of length of stay was poorer, 65% (range 60–80%), but the difference between observed and predicted lengths of stay were not significantly different. Conclusion: Artificial neural network ensembles can predict disposition for infants and toddlers with bronchiolitis; however, the prediction of length of hospital stay is not as good.
Feasibility of the Use of Phosphodiesterase Type 5 Inhibitors in a Pharmacologic Prevention Program for Recurrent Priapism

ABSTRACT Introduction Recurrent ischemic priapism is an enigmatic erectile disorder in need of improved clinical interventions to avert its known, potentially serious complications. Aim To evaluate the use of a long‐term, continuous phosphodiesterase type 5 (PDE5) inhibitor therapeutic regimen in controlling recurrent ischemic priapism and its feasibility in a clinical management program for the disorder. Main Outcome Measures The main outcome measure was reduction in frequency or duration of priapism episodes. A secondary outcome measure was preservation of erectile ability. Methods We retrospectively evaluated the clinical progress of seven patients (age 22–37 years) with sickle cell disease‐associated “stuttering” priapism (N = 4) and idiopathic recurrent priapism (N = 3), who were counseled and consented to the “off‐label” use of the PDE5 inhibitors sildenafil citrate and tadalafil. The medications were administered according to a specified therapeutic regimen based on scientific evidence that chronic PDE5 inhibitor administration in priapism contexts effectively reconditions PDE5 regulatory function in the penis. The duration of clinical follow‐up extended through 2 years. Results All seven patients were confirmed to have recurrent ischemic priapism without identifiable pharmacologic, traumatic, or neoplastic disease associations based on clinical history, physical examination, laboratory testing, and penile diagnostics. PDE5 inhibitor treatment was successful in alleviating or resolving priapism recurrences in six of the seven patients. Erectile function was unchanged in six patients and improved in one patient at last follow‐up compared with baseline status. All the patients reported that PDE5 inhibitor therapy was well tolerated and did not cause any adverse effects limiting their continued use of the medication. Conclusions Because of their efficacy, safety, and tolerability as shown in this case series, PDE5 inhibitors would appear to have a possible role in a rigorously implemented clinical management program to control recurrent priapism. However, completion of a controlled clinical trial is necessary to confirm the utility of this treatment. Burnett AL, Bivalacqua TJ, Champion HC, and Musicki B. Feasibility of the use of phosphodiesterase type 5 inhibitors in a pharmacologic prevention program for recurrent priapism. J Sex Med 2006;3:1077–1084.
Scalar gravitation: A laboratory for numerical relativity. III. Axisymmetry.

We construct a two-dimensional axisymmetric mean-field particle simulation scheme that solves the equations of relativistic scalar gravitation coupled to collisionless matter. Although scalar gravitation theory disagrees with experiment, it is useful as a testing ground for numerical methods used to solve the equations of general relativity, particularly in the generation of gravitational waves. We discuss methods for extracting the gravitational wave amplitude from the field variables, as well as methods for imposing an accurate outgoing-wave boundary condition on the scalar field at a finite radius. We find that for continuous matter distributions, our code is able to calculate smooth and accurate gravitational wave forms, despite the stochastic representation of the matter source terms caused by sampling with a finite number of particles. A similar scheme should provide accurate wave forms in general relativity, provided sufficient computer resources are used.
What Kind of Media, and When? Public Opinion about Press Coverage of Politicians' Private Lives

Respondents in a southern state telephone survey agreed that media coverage of public leaders' private lives is an important news media responsibility, with agreement greater for legacy media than for online media, and differing depending on hypothetical scenario. The data also suggest increasing tolerance for such coverage and growing belief in responsibility of media to report on private indiscretions relative to previous studies.
Path Dependence of Shape Memory Alloys during Cyclic Loading

It has long been recognized that Ni-Ti shape memory alloys (SMAs) behave pseudo-elastically above the austenite finish temperature (Af) with a nearly perfectly plastic character during the initial cycles of transformation. Under conditions of cyclic loading with a maximum strain ∈max, the critical stress to initiate stress-induced martensitic (SIM) transformation decreases, the strain-hardening rate increases, residual strain accumulates and the hysteresis energy progressively decreases over many cycles of loading. Hence the hysteresis energy available for dissipation gradually decreases during cycling. Recent work (Miyazaki et al., 1981, 1986; Contardo and Guenin, 1990; Filip and Mazanec, 1994) has shown that dislocations are generated in the alloy during the phase transformation to accommodate formation of SIM, giving rise to the change of hysteresis behavior of the SMA. Upon loading the SMA to a strain level higher than ∈max, the alloy behaves almost identical to the "virgin material". Likewise, it has...
Oral β-lactams applied to uncomplicated infections of skin and skin structures

Uncomplicated skin and skin structure infections (uSSSIs) include impetigo, erysipelas, folliculitis, simple abscesses, and cellulitis. Their common bacterial causative agents include Staphylococcus aureus and Streptococcus pyogenes. Current guidelines predate the widespread occurrences of methicillin-resistant S. aureus (MRSA) as a community-acquired pathogen and include dicloxacillin, cephalexin, erythromycin, clindamycin, and amoxicillin/clavulanic acid, all orally, or mupirocin ointment applied topically, for impetigo. For other uSSSI, recommendations are based on the probability of the infection being caused by MRSA. If methicillin-susceptible S. aureus (MSSA) are known or suspected, the oral agents recommended include clindamycin, dicloxacillin, cephalexin, doxycycline, minocycline, and trimethoprim-sulfamethoxazole (SXT). For MRSA, recommended oral agents are linezolid, clindamycin, doxycycline, minocycline, and SXT. Because community-acquired MRSA infections now predominate in patients with abscesses in the United States, agents recommended for MRSA should be used for this indication. Local susceptibility patterns should guide empiric therapy. However, no placebo-controlled trials of uSSSI are available, and the evidence used to generate these recommendations is based on comparative noninferiority studies, often with wide noninferiority margins and confidence intervals. The evidence used in developing current guidelines therefore has significant limitations. Further studies, such as superiority outcome studies, placebo-controlled studies, measurement of time to resolution, or other novel approaches, are needed to resolve these treatment dilemmas. Until such studies are performed, the best surrogate available for predicting clinical outcome is application of pharmacokinetic and pharmacodynamic principles; these describe in vivo drug behavior and allow determination of susceptibility breakpoints for predicting in vivo antimicrobial efficacy via attainment of antimicrobial targets.
Key exchange using ‘keyless cryptography’

Abstract Protocols to generate and distribute secret keys in a computer network are described. They are based on keyless cryptography , a new cryptographic technique where information is hidden by only keeping the originator of a message, and not its contents, secret.
A randomized trial of medical care with and without physical therapy and chiropractic care with and without physical modalities for patients with low back pain: 6-month follow-up outcomes from the UCLA low back pain study.

Study design A randomized clinical trial. Objectives To compare the effectiveness of medical and chiropractic care for low back pain patients in managed care; to assess the effectiveness of physical therapy among medical patients; and to assess the effectiveness of physical modalities among chiropractic patients. Summary of background data Despite the burden that low back pain places on patients, providers, and society, the relative effectiveness of common treatment strategies offered in managed care is unknown. Methods Low back pain patients presenting to a large managed care facility from October 30, 1995, through November 9, 1998, were randomly assigned in a balanced design to medical care with and without physical therapy and to chiropractic care with and without physical modalities. The primary outcome variables are average and most severe low back pain intensity in the past week, assessed with 0 to 10 numerical rating scales, and low back-related disability, assessed with the 24-item Roland-Morris Disability Questionnaire. Results Of 1,469 eligible patients, 681 were enrolled; 95.7% were followed through 6 months. The mean changes in low back pain intensity and disability of participants in the medical and chiropractic care-only groups were similar at each follow-up assessment (adjusted mean differences at 6 months for most severe pain, 0.27, 95% confidence interval, -0.32-0.86; average pain, 0.22, -0.25-0.69; and disability, 0.75, -0.29-1.79). Physical therapy yielded somewhat better 6-month disability outcomes than did medical care alone (1.26, 0.20-2.32). Conclusions After 6 months of follow-up, chiropractic care and medical care for low back pain were comparable in their effectiveness. Physical therapy may be marginally more effective than medical care alone for reducing disability in some patients, but the possible benefit is small.
Micromorphic record and interpretations of carbonate forms in the Rolling Plains of Texas

Abstract The Rolling Plains of Texas comprises about 10 million hectares of soils developed in Permianage deposits. Most soils occur on erosional landscape positions. Soils have ustic moisture regimes and thermic temperature regimes. These soils have developed in a wide variety of sediments ranging from red bed shales to sandstones. Most of the soils have carbonate-enriched Bk horizons while parent materials are slightly- to non-calcareous. Pedogenic calcite usually occurs as nodules, calcans, neocalcans and crystallaria. Calcite nodules are the dominant form in upper Bk horizons, while the other forms occur primarily in lower Bk/Cr horizons. Additional forms of calcite include pseudomorphs after gypsum and equant anhedral calcite which fill fracture or joint seams, and sand-calcite crystals (poikilotopic). These are considered pedogenic although formed under an earlier climatic regime. Dolomite, a post-depositional lithogenic mineral, occurs as nodules, intercalary crystals and clustered to dispersed microsparite crystals. Micromorphic forms of calcite indicate that the soils have been through several major and minor fluctuations in the soil chemical environment. On stable landscape positions, carbonate minerals preserve the long-term pedogenic record of soil development.
On asymptotic distribution of the test statistic for the mean of the non-isotropic principal component

In this paper, the authors derived the large sample distribution of the t statistic based upon the observations on the first principal component instead of the original variables. It is shown that the above statistic is distributed asymptotically as Student's t distribution.
Enhancing and Calibrating the Rakha-Pasumarthy-Adjerid Car-Following Model using Naturalistic Driving Data

The research presented in this paper analyzes the simplified behavioral vehicle longitudinal motion model, currently implemented in the INTEGRATION software, known as the Rakha-Pasumarthy-Adjerid (RPA) model. The model utilizes a steady-state formulation along with two constraints, namely: acceleration and collision avoidance. An analysis of the model using the naturalistic driving data identified a deficiency in the model formulation, in that it predicts more conservative driving behavior compared to naturalistic driving. Much of the error in simulated car-following behavior occurs when a car-following event is initiated at a spacing that is often much shorter than is desired. The observed behavior is that, rather than the following vehicle decelerating aggressively, the following vehicle coasts until the desired headway/spacing is achieved. Consequently, the model is enhanced to reflect this empirically observed behavior. Finally, a quantitative and qualitative evaluation of the original and proposed model formulations demonstrates that the proposed modification significantly decreases the modeling error and produces car-following behavior that is consistent with empirically observed driver behavior.
A 4800 bit/s microprocessor-based CCITT compatible data modem

Abstract The microprocessor-based implementation of data modems has been attracting a great deal of scientific interest in the past decade. It is a kind of interdisciplinary field where both information theory and microprocessor engineering strongly interact. A number of different microprocessor-based modems are available on the market. Most of the modems with speeds above 2400 bit/s are commonly implemented on bit-slice processors (e.g., AMD 2900) or fast and expensive MOS microprocessors (e.g., TMS 320). For these speeds, it is considered that slow and cheap MOS microprocessors (e.g., Intel 8085) can be used only at the cost of simplifications in the algorithms for signal demodulation and detection, i.e., at the cost of decreased performance. This paper, however, describes a MOS microprocessor-based implementation of the 4800 bit/s modem which was achieved without any deterioration of the modem performance. Both algorithmic details (connected with the processing of signals) and implementational details (connected with the microprocessor-based implementation) are given.
Ab initio calculations of the ultraviolet resonance Raman spectra of uracil

An equation been derived to calculate, ab initio, the frequencies and intensities of a resonant Raman spectrum from the transform theory of resonance Raman scattering. This equation has been used to calculate the intensities of the ultraviolet resonance Raman spectra from the first π-π* excited state of uracil and 1,3-dideuterouracil. The protocol for this calculation is as follows: (1) The force constant matrix elements in Cartesian coordinate space, the vibrational frequencies, and the minimum energy ground and excited state geometries of the molecule are calculated ab initio using the molecular orbital program Gaussian 92, (2) the force constants in Cartesian coordinates are transformed into force constants in the space of a set of 3N – 6 nonredundant symmetrized internal coordinates, (3) the G matrix is constructed from the energy minimized ground state Cartesian coordinates and the GFL = LΛ eigenvalue equation is solved in internal coordinate space, (4) the elements of the L and L−1 matrices are calculated, (5) the changes in all of the internal coordinates in going from the ground to the excited state are calculated, and (6) these results are used in combination with the transform theory of resonance Raman scattering to calculate the relative intensities of each of the 3N – 6 vibrations as a function of the exciting laser frequency. There are no adjustable parameters in this calculation, which reproduces the experimental frequencies and intensities with remarkable fidelity. This indicates that the Dushinsky rotation of the modes in the excited state of these molecules is not important and that the simplest form of the transform theory is adequate. © 1995 John Wiley & Sons, Inc.
Erythrocyte Destruction by Prosthetic Heart Valves

Immediate hemolysis induced by eight aortic and five mitral valve prostheses was measured in in vitro steady- and pulsatile-flow systems. The mean index of hemolysis (IH) for the aortic valves ranged from 0.010 to 0.031 and 0.012 to 0.035 with steady and pulsatile flow, respectively. The IH for the mitral valves ranged from 0.004 to 0.021 in the steady-flow system, and from 0.011 to 0.021 in the pulsatile system. The Barnard-UCT aortic valve and the Kay-Shiley and Portex-Hammersmith mitral valves produced the least hemolysis in each group. The graphite-benzalkonium-heparin-coated Gott-Daggett valve was the most hemolytic valve in both the mitral and the aortic groups. The degree of hemolysis demonstrated in these experiments appears to be important, particularly since several factors which are likely to have minimized these data have been cited. The calculated daily hemoglobin released from a single prosthetic valve represents a substantial fraction of a human's total hemoglobin clearance capacity and red...
Predictors of quality of life in patients at one year after heart transplantation

Abstract Background A multivariate approach to the study of relationships between quality of life and demographic, physical, and psychosocial variables after heart transplantation has not been examined in a large, multi-site sample. The purpose of this study was to describe quality of life, examine relationships between quality of life and demographic, physical, and psychosocial variables, and identify predictors of quality of life in patients who were 1 year post heart transplantation. % Methods: Data were collected from a nonrandom sample of adult patients ( n = 232) who were 1 year post heart transplantation at a Midwestern or Southern medical center. Nine self-administered instruments and chart review were used to gather data from patients. All tools had adequate psychometric support. Descriptive statistics, Pearson correlations, and step-wise multiple regression were used to analyze data. Level of significance was set at 0.05. Results Patients were most satisfied with the areas of quality of life regarding social interaction and least satisfied with their psychological state. Patients experienced an average amount of stress, were coping fairly well, reported overall good quality of life, and were very satisfied with the outcome of their transplant surgery. Nine out of 16 variables were significant predictors of quality of life and explained 66% of the variance in quality of life: less stress, more helpfulness of information from health care providers, better health perception, better compliance with the transplant regimen, more effective coping, less functional disability, less symptom distress, older age, and fewer complications. Conclusions Predictors of quality of life at 1 year after heart transplantation were primarily psychological. Additional variance in quality of life was explained by physical, somatic sensation, demographic, and health status variables. Knowledge of these factors provides (1) information to identify patients who are at risk for poor quality of life at 1 year after heart transplantation and (2) direction for the development of interventions to improve quality of life.
Nitric oxide red blood cell membrane permeability at high and low oxygen tension.

Abstract Red blood cell (RBC) encapsulated hemoglobin in the blood scavenges nitric oxide (NO) much more slowly than cell-free hemoglobin would. Part of this reduced NO scavenging has been attributed to an intrinsic membrane barrier to diffusion of NO through the RBC membrane. Published values for the permeability of RBCs to NO vary over several orders of magnitude. Recently, the rate that RBCs scavenge NO has been shown to depend on the hematocrit (percentage volume of RBCs) and oxygen tension. The difference in rate constants was hypothesized to be due to oxygen modulation of the RBC membrane permeability, but also could have been due to the difference in bimolecular rate constants for the reaction of NO and oxygenated vs deoxygenated hemoglobin. Here, we model NO scavenging by RBCs under previously published experimental conditions. A finite-element based computer program model is constrained by published values for the reaction rates of NO with oxygenated and deoxygenated hemoglobin as well as RBC NO scavenging rates. We find that the permeability of RBCs to NO under oxygenated conditions is between 4400 and 5100 μm s−1 while the permeability under deoxygenated conditions is greater than 64,000 μm s−1. The permeability changes by a factor of 10 or more upon oxygenation of anoxic RBCs. These results may have important implications with respect to NO import or export in physiology.
Graphs omitting a finite set of cycles

We prove that for C a finite set of cycles, there is a universal C-free graph if and only if C consists precisely of all the odd cycles of order less than same specified bound. The sufficiency of this condition was proved by Komjath, Mekler, and Pach (Israel J. Math64 (1988), 158–168). © 1996 John Wiley & Sons, Inc.
Dynamics of telomere length variation in tetrahymena thermophila

Abstract We have analyzed the mechanism and dynamics of telomere length variation in the macronucleus of Tetrahymena thermophila. In a newly differentiated macronucleus, the average length of the telomeric repeated sequence, (C 4 A 2 ·T 2 G 4 )n, is closely regulated. In contrast, in vegetatively dividing cells in log phase, all macronuclear: telomeric sequences lengthen coordinately by 3–10 bp per generation until up to 1000 bp are added. In both elongated and short telomeres, characteristic single-stranded breaks on both strands are distally located. Reduction of elongated telomeres to their original length involves either the appearance of a novel type of variant cell, incapable of net telomere elongation, or, under stationary phase conditions, a reversible removal of telomeric sequences. The demonstration that telomeres are dynamic structures provides evidence for a model of telomere length regulation by activities that add and remove telomeric repeats.
Hypersensitive substrate for ribonucleases

A substrate for a hypersensitive assay of ribonucleolytic activity was developed in a systematic manner. This substrate is based on the fluorescence quenching of fluorescein held in proximity to rhodamine by a single ribonucleotide embedded within a series of deoxynucleotides. When the substrate is cleaved, the fluorescence of fluorescein is manifested. The optimal substrate is a tetranucleotide with a 5',6-carboxyfluorescein label (6-FAM) and a 3',6-carboxy-tetramethylrhodamine (6-TAMRA) label: 6-FAM-dArUdAdA-6-TAMRA. The fluorescence of this substrate increases 180-fold upon cleavage. Bovine pancreatic ribonuclease A (RNase A) cleaves this substrate with a k (cat)/ K (m)of 3.6 x 10(7)M(-1)s(-1). Human angiogenin, which is a homolog of RNase A that promotes neovascularization, cleaves this substrate with a k (cat)/ K (m)of 3. 3 x 10(2)M(-1)s(-1). This value is >10-fold larger than that for other known substrates of angio-genin. With these attributes, 6-FAM-dArUdAdA-6-TAMRA is the most sensitive known substrate for detecting ribo-nucleolytic activity. This high sensitivity enables a simple protocol for the rapid determination of the inhibition constant ( K (i)) for competitive inhibitors such as uridine 3'-phosphate and adenosine 5'-diphos-phate.
FACTORS AFFECTING LYING BEHAVIOR AND STALL UTILIZATION OF DAIRY CATTLE

Abstract Intensive management of dairy cattle in free-stall housing during the dry period may impose unknown stresses. In this study, factors affecting laterality (side cow lies on), and stall usage under relatively uncrowded conditions by dairy animals in late pregnancy were evaluated. Fifty-nine dry Holstein cows and 18 heifers were observed during seven 24-h periods. Left laterality was observed 64.7 ± 1.1% of the time for cows and 61.8 ± 2.7% of the time for heifers. Exercise had no significant effect on laterality. When a single stall was occupied either to right or left of a cow, a significant number lay with dorsal side (backbone) toward the occupied stall. A 2% slope across the stall width had a highly significant effect on laterality. Cows preferred to lie with their dorsal side uphill. Right laterality increased with age of cows but decreased with approaching calving. Averages and standard deviations for length of resting episodes (min), stalls used, and number of resting episodes in each 24-h period were 82.5 (62.9), 4.7 (2.0) and 6.5 (2.9), respectively. There was not a significant single stall preference, but cows chose one side of the shed significantly more than the other. In designing free-stall housing for dry cow comfort, these results indicate that a downhill slope to a cow's right as she faces the stall and access to a dry lot during warm weather would be ideal.
Mathematical and computational models of immune-receptor signalling.

The process of signalling through receptors of the immune system involves highly connected networks of interacting components. Understanding the often counter-intuitive behaviour of these networks requires the development of mathematical and computational models. Here, we focus on the application of these models to understand signalling through immune receptors that are involved in antigen recognition. Simple models, which ignore the details of the signalling machinery, have provided considerable insight into how ligand–receptor binding properties affect signalling outcomes. Detailed models, which include specific molecular components and interactions beyond the ligand and receptor, are difficult to develop but have already provided new mechanistic understanding and uncovered relationships that are difficult to detect by experimental observation alone. They offer hope that models might eventually predict the full spectrum of signalling behaviour.
3-D finite-volume model of dam-break flow over uneven beds based on VOF method

A 3-D numerical model has been developed to simulate dam-break flow over uneven beds in irregular domains. The model solves the Reynolds-Averaged Navier–Stokes equations (RANS) using a finite-volume method based on collocated mesh that fits the solid boundaries such as bed and walls. The velocity and pressure coupling is achieved using the PISO algorithm and the Rhie and Chow’s momentum interpolation. The Smagorinsky eddy viscosity model is used for turbulence closure of the RANS equations. The movement of water surface is captured using the Volume-of-Fluid (VOF) method with the Compressive Interface Capturing Scheme for Arbitrary Meshes (CICSAM) to solve the VOF advection equation. The accuracy and robustness of the model has been tested using several small- and large-scale laboratory experiments of dam-break flow. Some comparisons between the calculated results by the present model and those calculated by depth-averaged 2-D and 3-D models in the literature are presented.
Changes Induced in Peroxidase Activity under Simulated Hypo‐gravity

A new method of inducing and maintaining a hypo-gravity environment is described. Using this new technique (buoyancy compensation), the effect of reduced gravitational stress on dwarf marigolds (Tagetes patula) was studied. It was found that the specific activity of peroxidase was elevated significantly in gravity compensated seedlings. This effect, discovered with the buoyancy compensators, was confirmed with plants grown on traditional clinostats.
Effect of age on detecting a loss of balance in a seated whole-body balancing task.

Abstract Background. Most falls are attributed to a loss of balance without a quantitative definition of the term. It has been proposed that a loss of balance is detectable as an unusually large (anomalous) value of the system control error. The hypotheses were tested that age will not affect the detection of control error anomaly, or prediction of the associated compensatory response, in a challenging balancing task. Methods. Twenty healthy older adults were asked to sit and balance a chair over its rear legs for as long as possible. The dominant foot’s ground reaction force and the chair’s sagittal-plane acceleration represented the system input and output, respectively. Control error was the difference between actual and expected acceleration output from a self-identified forward internal model of the system. A control error anomaly was detected once the error crossed a threshold set at three standard deviations (3-Sigma) above the mean of baseline data. Results from five trials were compared to published results in 20 healthy young adults. Findings. A control error anomaly was successfully detected in 91% of 91 older adult trials, statistically similar to the 92% success rate obtained previously in young adults. A response was predicted in 57% of the 77 older adult trials with responses, significantly less than the 92% obtained in the young adult trials (age effect significant: P Interpretation. The condition leading to uncontrolled backward acceleration of the chair was reliably detected in both groups. While the young waited to respond to this condition, older subjects responded prematurely.
Recent Progress in Cyano Complexes of Platinum and Gold as Sensitizers of Lanthanide Emissions

Lanthanide ions have sharp characteristic emission in the visible and near-infrared (NIR) ranges, long luminescence lifetimes, and large Stokes shifts, which make them very attractive candidates for the development of optical devices, including as light conversion materials. The potential for these and other applications requires a new approach in the choice of chromophores suitable for lanthanide sensitizations. Although great progress has been made to circumvent the problem of inefficient direct f-f absorption in lanthanide systems through the process of sensitization, the conversion efficiency of the absorbed photon to visible emission is typically low, except in a few cases. A class of chromophores involving transition metal complexes is emerging as a suitable choice as a sensitizer for lanthanide ion acceptors. A major advantage afforded by these chromophores is their ability to sustain a better energy match-up with most Ln3+ acceptor states. Unique advantages of metal complexes over organic chromoph...
Environment and Trade in General Equilibrium: Theory, Methodology, and Evidence: Discussion

The subtitle of this three-paper session-theory, methodology, and evidence-is particularly apt, since each paper deals primarily with one of the three items. The Copeland-Taylor paper is a theoretical contribution to the debate, "Is free trade good or bad for the environment?" The Espinosa-Smith paper, although it presents empirical results, is mainly a methodological contribution showing how to incorporate nonmarket information into a computable general equilibrium (CGE) model. Finally, the Beghin, Roland-Holst, and van der Mensbrugghe paper provides evidence in the form of simulation results of trade liberalization and emissions taxes
“So My Family Can Survive:” Prisoner Re-Entry and the Risk and Resilience of Black Families

Given the thousands of African American men that are released from prison each year, a growing number of national, state and local programs have been established to facilitate easier transitions for these men into the workforce. However, very little is known about the relational risk and resilience factors of married and cohabiting African American men and their partners after their release from prison. More specifically, there is a lack of data that addresses the qualitative responses of married and cohabiting African Americans regarding the following seven dimensions: (a) factors associated with initial attraction; (b) feelings when they realized they were in a “coupled” relationship; (c) post-cohabitation adjustments; (d) the meaning of commitment; (e) perceptions regarding how being in a relationship changed their lives; (f) perceptions regarding how the relationship expanded the couple’s view of commitment; as well as (g) couple perceptions regarding the future of their relationship. To address this paucity, this paper will feature narratives provided by two previously incarcerated African American men (one married; one cohabiting) and their partners. Qualitative analyses of the data resulted in risk and resilience themes related to each of the aforementioned dimensions. Themes were related to the start of the relationship, perceptions regarding in a “coupled” relationship, psychological and behavioral changes after cohabitation, the definition and demonstration of commitment, how being in a relationship positively changed the lives of these couples, broadened how they think about commitment, as well as confidence regarding the future of their relationship. Supporting qualitative data are presented in connection with each theme. Using qualitative coding and analysis, implications and recommendations regarding how national, state, and local programs can identify the risks and further develop the strengths of these men are also provided.
Zinc uptake by cultured human lymphoblasts

At physiological plasma concentrations (12–20 μM), zinc uptake by cultured human B lymphoblasts is biphasic with an early, rapid, saturable phase, followed by a slower, unsaturable phase. The saturable component is specific for zinc and cadmium, with aK m of 1–2 μM and aV max of 3.0 pmol/min/106 cells. This early phase does not require metabolic energy derived directly from ATP or the presence of sulfhydryl groups. At higher zinc concentrations (>30 μM), zinc uptake is more complex, although biphasic kinetics are also evident.
Optical control of yields of CO photodesorbed from Cu(001) by chirped light pulses: density matrix theory and calculations

Abstract Yields of CO photodesorbed from Cu metal surfaces by absorption of femtosecond chirped pulses of visible light are obtained within a density matrix approach, including the non-linear optical response of the substrate for pulses of large fluence. Our model is based on potential energy surfaces, couplings and transition dipoles parametrized from electronic structure calculations for CO/Cu. Results show that the yields of desorbed CO can be controlled by both positive and negative chirping, to obtain either a suppression or an enhancement of the yield. The effect can be as large as a doubling of the yields.
Will fatty worms help cure human obesity

The incidence of obesity has reached epidemic proportions within industrial societies; however, research on human obesity has been hampered by our inability to control genetic and environmental factors. The control of energy homeostasis appears to be conserved among species. Recent creative research in Caenorhabditis elegans, including the application of a genome-wide RNA interference analysis, has provided insight into the genes involved in energy balance. In this article, we discuss the results of these studies and their potential importance to humans.
Réseaux polyuréthanne: étude théorique et expérimentale de leurs propriétés élastiques

Resume On a etudie les relations structure-proprietes de reseaux polyurethanne. La fraction sol, le taux de gonflement et le module elastique ont ete determines. Les parametres structuraux tires de ces mesures ont ete comparees aux previsions theoriques. Les resultats conduisent a attribuer a ces gels un comportement intermediaire entre ceux prevus par les modeles du reseau fantome et du reseau affine.
Distribution of phosphatidylethanolamine arachidonic acid in platelet membranes.

Abstract Arachidonic acid (20:4) and other fatty acids and aldehydes in phosphatidylethanolamine (PE) present on the platelet surface was determined. Surface-exposed PE was isolated by using 2,4,6-trinitrobenzenesulfonate, a nonpenetrating probe (Schick, P.K., Kurica, K.B. and Chacko, G.K. (1976) J. Clin. Invest. 57, 1221–1226). PE contains 50% total platelet arachidonic acid. Approx. 16% platelet PE is present on the platelet surface. The study showed that the fatty acid and aldehyde composition of PE on the platelet surface is virtually identical to that in PE present inside the platelet. Therefore, 8 nmol arachidonic acid are present in PE in the outer layer of the plasma membrane in 109 platelets.
Detection of Atherosclerosis in Human Artery by Mid-Infrared Attenuated Total Reflectance

Atherosclerosis, with its clinical sequelae, is the most common cause of death in the United States. In the atherosclerotic process, the innermost layer of the arterial wall becomes thickened due to cellular proliferation and the accumulation of cholesterol and lipids. The primary means of characterizing atherosclerotic lesions is histochemical analysis, in which arterial wall cross sections are studied under a microscope. This method requires removal of arterial tissue and is therefore not suited to arterial wall characterization in vivo. Consequently, histopathological information is rarely available clinically for selecting an appropriate therapy. To overcome this limitation, researchers are exploring several nondestructive techniques, such as ultrasound, UV-visible absorption, and UV-visible fluorescence, as alternative methods of probing arterial wall composition and structure.
The firm export and FDI choice in the context of gravity

Abstract In this paper, I show that in a theoretical environment where monopolistic competitive firms choose between exporting and servicing through a multinational with foreign direct investment (FDI), a gravity representation of exports and FDI can be derived. I then discuss the extent to which the resulting gravity equations are comparable and suggest a gravity-type regression that allows for direct interpretation of the differential effects of variables on exports and FDI.