cssi/SciSciGPT-SciSciNet huggingface dataset:
Isolation, Characterization, and Regulation of the Prolactin Receptor

Abstract The prolactin, or lactogenic hormone, receptor has been purified (∼ 80%) from lactating mouse liver and human term placenta by the nondenaturing zwitterionic detergent 3-[(3-cholamidopropyl) -dimethylammonio] -1-propane sulfonate and a prolactin affinity column. The isolated "core-binding unit" has a molecular weight of 37,000±2,000 daltons. It retains the specificity for lactogenic hormones and binds prolactin with an affinity (K a = 2 to 6×10 9 M −1 ) similar to that of the receptor as it occurs in its membranous environment (K a = 3 to 5×10 9 M −1 ). Whether this "core-binding unit" exists on the cell surface in a cryptic or active form is influenced greatly by its association with other membrane proteins and the concentration of phosphatidylcholine within its local membranous environment.
Brain death documentation: analysis and issues.

Objective Specific guidelines for documenting the complete loss of brain function, for the declaration of brain death, have been established for 3 decades. This study assessed the quality and completeness of brain death notes and the effects of delays between notes on organ procurement. Methods A retrospective review of brain death declarations at a major medical center was performed. Fifty-eight cases, with a total of 121 brain death notes, were identified in a 12-month period. Notes were assessed for clinical and confirmatory tests of brain and brainstem function. Adverse physiological events that occurred in the time intervals between notes were also identified. Results The clinical tests most likely to be documented were tests of pupillary (86%) and gag (78%) reflexes. Corneal reflexes were tested in only 57% of cases, and motor responses were noted in only 66%. Documentation by the neurosurgery department was generally more complete. The delays between brain death declarations were highly variable but did not result in any loss of donor organs because of hemodynamic derangements. Conclusion To meet the needs of organ recipients and donor families and to comply with hospital, legal, and legislative mandates, hospitals may need to increase quality assurance activities with respect to declarations of brain death. Increased physician education should improve awareness of uniform brain death declaration guidelines.
Simple nonparametric tests for a known standard survival based on censored data

It is often of interest in survival analysis to test whether the distribution of lifetimes from which the sample under study was derived is the same as a reference distribution. The latter can be specified on the basis of previous studies or on subject matter considerations. In this paper several tests are developed for the above hypothesis, suitable for right-censored observations. The tests are based on modifications of Moses' one-sample limits of some classical two-sample rank tests. The asymptotic distributions of the test statistics are derived, consistency is established for alternatives which are stochastically ordered with respect to the null, and Pitman asymptotic efficiencies are calculated relative to competing tests. Simulated power comparisons are reported. An example is given with data on the survival times of lung cancer patients.
Advances in the Type I Boston Keratoprosthesis

Purpose: To give an update on the Type I Boston keratoprosthesis (KPro). Methods: We reviewed our recent experiences with the Type I Boston KPro with attention to design modifications, use in pediatric patients, post-operative care and management of complications. Results: The use of the Type I Boston KPro has increased dramatically since 2003, when only 57 of these devices were implanted. In 2006, more than 450 Type I Boston KPro’s were implanted worldwide. Recent modifications include a threadless front plate stem designed to reduce trauma to and maintain the health of the carrier corneal graft. The Type I Boston KPro appears to be a viable alternative to PK in children with corneal opacities and may simplify amblyopia management. Post-operative care following Boston KPro placement remains critical, with availability of preserved vancomycin reducing the risk of endophthalmitis. Management of complications including cataract formation and retinal detachment following Boston KPro will be discussed. Conclusions: The Type I Boston keratoprosthesis has shown continued acceptance among corneal surgeons throughout the world. Ongoing work at our institution aims to improve the utility of this device while minimizing complications from its use.
High tide movements of the temperate-zone herbivorous fish Cebidichthys violaceus (Girard) as determined by ultrasonic telemetry☆

Miniature, high-frequency (250 kHz), acoustic transmitters attached to the internal surface of the operculum were used to monitor the high tide movements of six medium-sized (225–410 mm SL) individuals of Cebidichthys violaceus (Girard) in the rocky intertidal zone near Piedras Biancas, California. The telemetry system consisted of a fixed, three-hydrophone array connected by cables to a shore-based receiver and microcomputer. Fish were tracked for sequences of 6 to 14 days, and the movements of as many as three individuals were monitored simultaneously. All fish showed a pattern of activity that was related primarily to the tidal cycle and secondarily to the diel cycle. Most movements of each fish occurred during flood tide. The three fish tracked in April were generally more active at night whereas the three tracked in June were more active during daylight hours. Differences in the time of flood tides with respect to the diel cycle may account for the dissimilarity in activity patterns of fish between the two months. Fish were highly restricted in their movements in that they were active < 1% of the time and traversed an area of ≈2 m2 or less per 40-min tracking episode. The results of this study coupled with known age and dietary attributes of the fish are consistent with the hypothesis that an energy-conserving lifestyle of low activity is the only one possible for a year-round, temperate-zone herbivore such as C. violaceus.
Imaging Analysis of Carbohydrate-Modified Surfaces Using ToF-SIMS and SPRi

Covalent modification of surfaces with carbohydrates (glycans) is a prerequisite for a variety of glycomics-based biomedical applications, including functional biomaterials, glycoarrays, and glycan-based biosensors. The chemistry of glycan immobilization plays an essential role in the bioavailability and function of the surface bound carbohydrate moiety. However, the scarcity of analytical methods to characterize carbohydrate-modified surfaces complicates efforts to optimize glycan surface chemistries for specific applications. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a surface sensitive technique suited for probing molecular composition at the biomaterial interface. Expanding ToF-SIMS analysis to interrogate carbohydrate-modified materials would increase our understanding of glycan surface chemistries and advance novel tools in the nascent field of glycomics. In this study, a printed glycan microarray surface was fabricated and subsequently characterized by ToF-SIMS imaging analysis. A multivariate technique based on principal component analysis (PCA) was used to analyze the ToF-SIMS dataset and reconstruct ToF-SIMS images of functionalized surfaces. These images reveal chemical species related to the immobilized glycan, underlying glycan-reactive chemistries, gold substrates, and outside contaminants. Printed glycoarray elements (spots) were also interrogated to resolve the spatial distribution and spot homogeneity of immobilized glycan. The bioavailability of the surface-bound glycan was validated using a specific carbohydrate-binding protein (lectin) as characterized by Surface Plasmon Resonance Imaging (SPRi). Our results demonstrate that ToF-SIMS is capable of characterizing chemical features of carbohydrate-modified surfaces and, when complemented with SPRi, can play an enabling role in optimizing glycan microarray fabrication and performance.
Impact of Concomitant Tricuspid Annuloplasty on Tricuspid Regurgitation, Right Ventricular Function, and Pulmonary Artery Hypertension After Repair of Mitral Valve Prolapse.

Abstract Background For patients undergoing mitral valve (MV) repair, the indications for and results of concomitant tricuspid annuloplasty remain controversial. Objectives This study was designed to compare a strategy of routine concomitant tricuspid annuloplasty for moderate tricuspid regurgitation (TR) or tricuspid annular dilation in patients undergoing degenerative MV surgery. Methods Of 645 consecutive patients (mean age 57 ± 13 years) undergoing primary repair of degenerative mitral regurgitation between 2003 and 2011, 419 (65%) underwent concomitant tricuspid annuloplasty for moderate TR and/or tricuspid annular dilation. These patients were retrospectively analyzed with longitudinal echocardiographic follow-up. Results Patients undergoing tricuspid valve repair were older (mean age 59.2 years vs. 52.3 years), had worse right and left ventricular function and higher pulmonary artery pressures, and were more likely to have had atrial fibrillation than patients undergoing isolated MV repair (all p Conclusions In patients with moderate TR or tricuspid annular dilation who were undergoing degenerative mitral repair, concomitant tricuspid annuloplasty is safe, effective, and associated with improved long-term right-sided remodeling. Routine treatment of moderate TR or tricuspid annular dilation at the time of MV repair appears to be beneficial.
Small signal impedance of heart cell membranes.

The electrical impedance of seven-day ventricular embryonic chick heart cell membranes maintained in tissue culture was measured under voltage clamp using the two-microelectrode voltage-clamp technique. Small sinusoidal perturbations were added to the voltage-clamp potential and the amplitude and phase of the steady-state sinusoidal response in current was recorded as a function of mean clamp potential or perturbing frequency. The experimental results are compared with two models of excitability for heart: the MNT model (McAllister, Noble & Tsien,J. Physiol. (London)251:1–59, (1975) and the BR model (Beeler & Reuter,J. Physiol. (London)268:177–210, 1977). The small signal impedance of heart cell membranes, in theory and experiment, shows a resonance near 1 Hz and near the threshold potential. The effect of this resonance is to increase the effective length constant of the membrane for these conditions.
Cardiac Troponins: Bench to Bedside Interpretation in Cardiac Disease

Cardiac troponins are the preferred biomarkers for the determination of acute myocardial necrosis. The high sensitivity of the available assays has significantly increased the detection of microscopic amounts of myocardial damage. Although compelling evidence indicates that elevated cardiac troponins are markers of poor prognosis and increased mortality, irrespective of the clinical scenario, small elevations can be seen in protean conditions and may confound the diagnosis of acute coronary syndromes. Emerging evidence suggests multiple different cellular mechanisms leading to cardiac troponin release, which challenge long held paradigms such as equivalency between troponin release into the circulation and irreversible cell death. Hence, knowledge of the physiology and pathophysiology of these cardiac biomarkers is essential for their accurate interpretation and consequent correct clinical diagnosis. Herein, the current relevant information about cardiac troponins is discussed, with special emphasis on pathophysiology and clinical correlates.
Ricco's Areas for S- and L-Cone Mechanisms Across the Retina.

The purposes of this study were to measure areas of complete spatial summation (i.e., Ricco's area) for S- and L-cone mechanisms and to evaluate whether the sizes of Ricco's area could be explained in terms of either the densities of photoreceptors or ganglion cells. Increment thresholds were measured at the fovea and at 1.5°, 4°, 8°, and 20° in the superior retina using a temporal two-alternative forced-choice procedure. Test stimuli ranging from -0.36 to 4.61 log area (min(2)) were presented on concentric 12.3° adapting and auxiliary fields, which isolated either an S- or L-cone mechanism on the plateau of the respective threshold vs. intensity function. The data indicate that from 0-20° retinal eccentricity, the size of Ricco's area is larger for the S-cone mechanism than the L-cone mechanism, increases monotonically for the L-cone mechanism, and, for both cone mechanisms, increases between 8-20° retinal eccentricity. This latter finding suggests that ganglion cell density rather than cone density defines the size of Ricco's area in the parafoveal and peripheral retina.
Independent Verification of Element 114 Production in the Ca 48 + Pu 242 Reaction

Independent verification of the production of element 114 in the reaction of 244-MeV $^{48}\mathrm{Ca}$ with $^{242}\mathrm{Pu}$ is presented. Two chains of time- and position-correlated decays have been assigned to $^{286}114$ and $^{287}114$. The observed decay modes, half-lives, and decay energies agree with published results. The measured cross sections at a center-of-target energy of 244 MeV for the $^{242}\mathrm{Pu}(^{48}\mathrm{Ca},3--4n)^{287,286}114$ reactions were ${1.4}_{\ensuremath{-}1.2}^{+3.2}\text{ }\text{ }\mathrm{pb}$ each, which are lower than the reported values.
ENHANCED PHOTOSYNTHETIC ASSIMILATION RATIOS IN ANTARCTIC POLAR FRONT (CONVERGENCE) DIATOMS1

Diatom populations from the Antarctic Polar Front (convergence) in the Drake Passage area exhibited relatively high photosynthesis : chlorophyll a ratios at light saturation. The permanent water column instability and the adverse meteorological conditions observed in the central Drake Passage area seem to product a light-color stress on the physiology of convergence diatoms that are restricted to a blue-green light environment during their life cycle. The enhanced photosynthesis : chlorophyll a ratios that were determined in experiments with Antarctic Polar Front diatoms when exposed to white (fluorescent) light sources, may bc related to the short-wavelength light background of these diatoms.
Sampling BIAS at Channel Junctions in Gated Flow Injection on Chips

The commonly used gated injection scheme was examined and found to suffer from multiple levels of electrokinetic sampling bias, including a new type based on transradial electrokinetic selection (TREKS). TREKS occurs as analytes of differing electrophoretic mobilities migrate around the corner at a channel junction in a microchip. The overall sample bias in gated injection was shown to be time-dependent and resulted in a larger sample bias against components of negative electrophoretic mobility. A new injection procedure for microchip devices based on interstream diffusion at zero potential is proposed. Diffusion of molecules into the separation channel is the main driving force for this type of injection. The new scheme is shown to be useful for injection of complex samples with multiply charged components, such as peptide mixtures. This procedure allows sampling of volumes from 12 to 45 pL, reproducible retention times (RSD < 1.5%), and reproducible peak areas (RSD < 2.3%).
Organic Sulfides in Hydrothermal Solution: Standard Partial Molal Properties and Role in Organic Geochemistry of Hydrothermal Environments

Thermodynamic properties for aqueous alkyl sulfides have been compiled and/or estimated through established methods. These properties are used to investigate reactions among various sulfur compounds in a variety of geological environments, ranging from sea floor hydrothermal systems to organic-rich sludge. Using thermodynamic data and the revised Helgeson-Kirkham-Flowers (HKF) equations of state, along with geochemical constraints imposed by the environment, it is possible to estimate the abiotic production of this class of organic sulfur compounds. For example, in hydrothermal systems in which H2 and H2S concentrations are buffered by the pyrite–pyrrhotite–magnetite (PPM) mineral assemblage, calculated equilibrium activities of dimethyl sulfide (DMS) are as high as 10−3 through formation reactions in which the environment contains millimolal concentrations of CO2. Higher activities are obtained when DMS formation from CO is considered and when more reducing mineral assemblages are present.
Response to the Barth Commentary (2012)

Richard Barth’s commentary on our research article (Spieker, Oxford, Kelly, Nelson & Fleming, 2012) of the first randomized clinical trial of Promoting First Relationships (PFR) notes the dearth of practices that are evidence-based, feasible, and available to support the healthy development of infants and toddlers in child welfare. Barth raises several important issues in his commentary. We appreciate the opportunity to explore these issues in greater depth, thereby contextualizing the development of PFR and its implementation in child welfare. We begin by elaborating on the history of the development and dissemination of the PFR program prior to the research published in Spieker et al., (2012.) Next, we place that history within a framework of program evaluation. Then we outline the complexities involved in a ‘real world’ evaluation of PFR. Finally, we clarify attachment theory as the theoretical foundation of the PFR approach and discuss why it is essential to focus on the parent-child relationship and caregiver sensitivity as a desired outcome. We will argue that there are several aspects of PFR that may make it relevant to child welfare.
Peripheral corneal relaxing incisions after excimer laser refractive surgery

Abstract Purpose: To evaluate the effectiveness of peripheral corneal relaxing incisions (PCRIs) for correcting corneal astigmatism after excimer laser refractive surgery. Setting: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA. Methods: In this retrospective case series, PCRIs were performed in 33 eyes (30 patients) that had residual astigmatism after photorefractive keratectomy or laser in situ keratomileusis according to a nomogram based on age and preoperative refractive astigmatism. Uncorrected visual acuity (UCVA) and refractive and keratometric astigmatism were evaluated, and vector analysis using the Holladay-Cravy-Koch formula was performed. Results: The percentage of eyes with a UCVA of 20/20 or better increased significantly from 6% (2/33) preoperatively to 61% (20/33) postoperatively (P Conclusion: Peripheral corneal relaxing incisions are an effective approach for correcting low amounts of corneal astigmatism in eyes that have had excimer laser refractive surgery.
Subepidermal vesiculobullous filarial dermatitis in free-ranging American badgers (Taxidea taxus).

Skin and superficial lymph nodes from the 65 juvenile ( 1 year old). Acute lesions consisted of multifocal vesiculobullous dermoepidermal separation and superficial perivascular dermatitis. Ultrastructural examination and Jones' silver-stained sections revealed separation between basal keratinocytes and the basal lamina (subepidermal vesiculation). Older lesions consisted of ulcerative superficial granulomatous dermatitis associated with ova and larvae. Multifocal granulomatous endolymphangitis, which involved afferent lymphatics of subcutaneous lymph nodes, was associated with viable as well as degenerative ova and larvae. Adult filarial worms were found in the subcutis alone and did not provoke an inflammatory reaction.
The regulation of pyruvate dehydrogenase by fatty acids in isolated rabbit heart mitochondria.

Abstract The rate of pyruvate oxidation by isolated rabbit heart mitochondria was inhibited by fatty acylcarnitine derivatives. The extent of inhibition by pyruvate oxidation in State 3 was greatest with palmitylcarnitine and only a minimal inhibition was observed with acetylcarnitine, while octanoylcarnitine or octanoate caused an intermediate extent of inhibition. Analyses of the intramitochondrial ATP ADP and NADH NAD + ratios under the different conditions of incubation indicated that it is unlikely that changes in either or both of these parameters were the primary negative effectors of the rate of pyruvate oxidation. A positive correlation between the decrease in the rate of pyruvate oxidation and the decrease in the level of free CoASH in the mitochondria was observed. Extraction and assay of the pyruvate dehydrogenase from rabbit heart mitochondria during the time course of the fatty acid-mediated inhibition of pyruvate oxidation indicated that pyruvate dehydrogenase was strongly inactivated when palmitylcarnitine was the fatty acid, while incubation with octanoate and acetylcarnitine resulted in less extensive inactivation of pyruvate dehydrogenase. Measurement of the effects of NADH, NAD + , acetyl-CoA, and CoASH on the inactivation of pyruvate dehydrogenase extracted from rabbit heart mitochondria indicated that NADH and acetyl-CoA activated the pyruvate dehydrogenasee kinase while CoASH strongly inhibited the kinase and NAD + was without effect. In addition, palmityl-CoA and octanoyl-CoA had little, if any, effect on the pyruvate dehydrogenase kinase activity. It was observed that palmityl-CoA but not octanoyl-CoA strongly inhibited the activity of the extracted pyruvate dehydrogenase. Hence, it is concluded that (a) decreased mitochondrial CoASH levels, which essentially remove a potent inhibitor of the pyruvate dehydrogenase kinase, (b) possibly a diminished free CoASH supply, which may be utilized as a substrate for the active complex, and (c) direct inhibitory effects of palmityl-CoA on the active form of the pyruvate dehydrogenase complex combine to make palmitylcarnitine a much more potent inhibitor of mitochondrial pyruvate oxidation than shorter chain length acylcarnitine derivatives.
French Local Politics: A Statistical Examination of Grass Roots Consensus*

The study of French politics has traditionally focused on the central issues of consensus and cleavage. Titles of representative works on French politics are revealing: In Search of France, France Against Herself, Crisis and Compromise, and France Torn. A foremost scholarly concern has been to explain the high degree of political conflict in France. Numerous explanations have been suggested, ranging from France's history to her values, regional diversity, and electoral system. However, in attempting to learn about French political behavior, an important source of information has been ignored. French local political patterns contrast sharply with national political patterns: the contrast is relevant to understanding the issues of consensus and cleavage in France.There are nearly 38,000 communes in France. Each elects a municipal council, and each municipal council (except the one for Paris) elects a mayor; there are manifold opportunities to examine French local consensus. Scholars have studied certain issues in French local government, but not the question of local consensus. French electoral sociologists have examined temporal changes of local voting patterns in national elections. Beginning with Andre Siegfried's Tableau politique de la France d'ouest sous la troisieme republique, these studies have provided detailed information on cantonal and even communal voting behavior. However, studies in electoral sociology are concerned with the result of the voting decision rather than with its causes. They do not question how local cleavages in national elections develop or are maintained. Still less do they examine local politics; their focus is primarily on municipalities' national voting behavior.
Improvement Technology and Research Contents of Machining Accuracy for CNC Machine Tools

To bring a new technological revolution, CNC technology and machines give the birth of a new era of control and production. The rapid development of CNC has considerably advanced the precision and ultra-precision machining technology to improve a new level and great attention. From error prevention and compensation, researches of the CNC machines precision at home and abroad were introduced. Key reasons for error compensation hardly use in the domestic widely were pointed out. Finally, the necessity and main contents of error compensation technology were presented according to the actual situation of enterprises.
A Passion for Difference: Essays in Anthropology and Gender

. Passion for Difference: Essays in Anthropology and Gender. Henrietta Moore. Bloomington: Indiana University Press, 1994. ix +177 pp., bibliography, notes, index.
Assessing landscape dynamics in a protected area

This article describes an approach to assessing spatial and temporal land-use and land-cover changes in and adjacent to protected areas and to the measurement of landscape stability within a protected area. Methods employed include aerial photographic interpretation and GIS technology. Odum's four-compartment ecosystem model provides the conceptual framework for assessing landscape stability. The study area is a selected sample of the Upper San Pedro National Riparian Conservation Area in the high desert grassland of southeastern Arizona. Significant changes were observed in the landscape matrix and riparian ecosystem. However, when these changes were assessed in the context of Odum's model, the change was nonsignificant. Implications of the approach and potential applications in protected area management are discussed.
A spectrophotometer-based method for crystallization induction time period measurement

Abstract A method for measurement of crystallization induction time periods using a spectrophotometer is described. The turbidity of lysozyme solutions at sodium chloride concentrations of 0%, 3%, 6%, 9% (w/v) in 0.1 M NaAc (pH 4.0) and a lysozyme concentration of 10 mg/ml was monitored at 350 nm and showed a dramatic increase after nucleation occurred. Heterogeneous sources of nucleation were removed via filtration with 100,000 and 500,000 MWCO filters. Larger pore size, 0.2 μm, filters were not able to remove these particles. The non-filtered and 0.2 μm filtered had the same turbidity profiles except that the 0.2 μm filtered had an induction time of 152 min compared with the 119 min induction time for the non-filtered solution. The 500,000 MWCO filter had a significant reduction in the formation of prenucleation aggregates and the induction time increased from 119 min for non-filtered to 178 min for the 500,000 MWCO filtered. Also, when the 100,000 MWCO filter was used there was no nucleation or crystallization over the 240 min time frame. The increase in turbidity was attributed to an increase in particle size and not to bacterial growth because the solutions were found to be free of bacteria or fungi by microbiological analysis. Results from hanging drop vapor diffusion crystallization on the same solutions used in the turbidity study indicate that the sources removed by filtration lead to nucleation. Finally, sodium azide was added to the solutions at a concentrations of 0.17% (w/w) and was found to interfere with or delay lysozyme nucleation.
Molecular determinants of coupling between the domain III voltage sensor and pore of a sodium channel

In voltage-gated sodium channels, a voltage-sensor domain communicates with the pore gate regions, but the details of this process remain unclear. Now the electromechanical coupling in a Na+ channel is probed by tryptophane scanning mutagenesis, together with structural modeling, with the results indicating a crucial role for the hinge regions.
Bioidentical hormones for menopausal hormone therapy: variation on a theme.

BACKGROUND Progesterone creams and natural or bioidentical compounded estrogen preparations are being promoted to consumers as safe alternatives to conventional menopausal hormone therapy and as health-promoting tonics. No reliable data support these claims.
Dynorphin release by the lateral olivocochlear efferents may inhibit auditory nerve activity: a cochlear drug delivery study.

Dynorphin (dyn) is suggested to excite the auditory nerve (AN) when released by the lateral olivocochlear (LOC) efferents. However, previous studies evaluated either intravenously delivered dyn-like agents, raising the potential for systemic (central) effects, or agent concentrations unlikely to be achieved via endogenous cochlear release. This study tested the hypothesis that biologically relevant increases in dyn levels in the cochlea achieved via diffusion of the drug of (−)pentazocine across the round window membrane enhances AN firing. In general, amplitude of the cochlear whole-nerve action potential (CAP) was depressed following drug application. These results suggest that dyn released by the LOC neurons would likely act as an inhibitory transmitter substance in the LOC system; neurotransmission is one of the LOC system's vast unknowns.
Technology assessment policy: top down or bottom up?

Abstract This paper briefy contrasts two approaches to formulating and implementing technology-related health policy. Policy changes are traditionally imposed from above, top down. However, policy changes related to adoption, diffusion, or rejection of new technologies for health care, can be very effective from the bottom up. The aggregated micro-decisions of thousands of health professionals and institutions can also become macro-policy, quite constructively. This paper argues for and documents the utility of bottom-up policy making.
Redundancy in Ribonucleotide Excision Repair: Competition, Compensation, and Cooperation

The survival of all living organisms is determined by their ability to reproduce, which in turn depends on accurate duplication of chromosomal DNA. In order to ensure the integrity of genome duplication, DNA polymerases are equipped with stringent mechanisms by which they select and insert correctly paired nucleotides with a deoxyribose sugar ring. However, this process is never 100% accurate. To fix occasional mistakes, cells have evolved highly sophisticated and often redundant mechanisms. A good example is mismatch repair (MMR), which corrects the majority of mispaired bases and which has been extensively studied for many years. On the contrary, pathways leading to the replacement of nucleotides with an incorrect sugar that is embedded in chromosomal DNA have only recently attracted significant attention. This review describes progress made during the last few years in understanding such pathways in both prokaryotes and eukaryotes. Genetic studies in Escherichia coli and Saccharomyces cerevisiae demonstrated that MMR has the capacity to replace errant ribonucleotides, but only when the base is mispaired. In contrast, the major evolutionarily conserved ribonucleotide repair pathway initiated by the ribonuclease activity of type 2 Rnase H has broad specificity. In yeast, this pathway also requires the concerted action of Fen1 and pol δ, while in bacteria it can be successfully completed by DNA polymerase I. Besides these main players, all organisms contain alternative enzymes able to accomplish the same tasks, although with differing efficiency and fidelity. Studies in bacteria have very recently demonstrated that isolated rNMPs can be removed from genomic DNA by error-free nucleotide excision repair (NER), while studies in yeast suggest the involvement of topoisomerase 1 in alternative mutagenic ribonucleotide processing. This review summarizes the most recent progress in understanding the ribonucleotide repair mechanisms in prokaryotes and eukaryotes.
Bacterial Skin Contamination Before and After Surgical Preparation of the Foot, Ankle, and Lower Leg in Patients with Diabetes and Intact Skin versus Patients with Diabetes and Ulceration: A Prospective Controlled Therapeutic Study

Eradication of bacterial flora from the foot, especially the nailfolds and toe webspaces, through surgical preparation remains a challenge. All previous studies have involved healthy patients undergoing elective foot and ankle surgery or healthy volunteers. However, the patient with diabetes is considered an immunocompromised host with decreased ability to combat invasive bacterial infections. The use of an efficacious surgical preparation is therefore of paramount importance. The author conducted a prospective study involving patients with diabetes with and without ulceration who underwent the current "best evidence available" surgical preparation (i.e., chlorhexidine gluconate [4%] scrub followed by alcohol impregnated with iodine [1%] solution). Qualitative aerobic cultures before and after completion of this surgical preparation technique were obtained from the hallux nailfold; second, third, and fourth toe webspaces (as one culture); and distal anterior tibia. A total of 120 organisms were cultured before surgical preparation with 64 in the elective group and 56 in the ulcerated group. The most commonly isolated organism was methicillin-resistant Staphylococcus epidermidis, which was identified in 46 pre-preparation cultures (38.3%). This was followed by methicillin-sensitive S. epidermidis (16.7%) and "other" organisms (10.0%). There was a significant reduction for both numbers of organisms identified and positive cultures for the 3 most commonly isolated organisms after surgical preparation. Based on the results of this study, the surgical preparation used here appears to be an efficacious surgical preparation technique for eradicating aerobic bacterial pathogens from the foot in patients with diabetes both with and without ulceration. The high incidence of methicillin-sensitive and methicillin-resistant S. epidermidis found in this patient population is a cause for concern, especially when metallic fixation is intended to be implanted.
Polar coordinate routing for multiple paths in wireless networks

We propose Polar Coordinate Routing (PCR) to create multiple paths between a source and a destination in wireless networks. Our scheme creates paths that are circular segments of different radii connecting a source and a destination. We propose a non-euclidean distance metric that allows messages to travel along these paths. Using PCR it is possible to maintain a known separation among the paths, which reduces the interference between the nodes belonging to two separate routes. Our extensive simulations show that while PCR achieves a known separation between the routes, it does so with a small increase in overall hop count. Moreover, we demonstrate that the variances of average separation and hop count are lower for the paths created using PCR compared to existing schemes, indicating a more reliable system. Existing multi-path routing schemes in wireless networks do not perform well in areas with obstacles or low node density. To overcome adverse areas in a network, we integrate PCR with simple robotic routing, which lets a message circumnavigate an obstacle and follow the trajectory to the destination as soon as the obstacle is passed.l
Effect of heart rate on myocardial relaxation in isometric twitches

Objective: Increased heart rate increases the amount of calcium that triggers myofilament interaction and thereby the load of calcium to be sequestered to cause relaxation, while decreasing the time for calcium sequestration. By studying the effect of heart rate on myocardial relaxation the hypothesis was therefore tested that increased heart rate impairs myocardial relaxation. Methods: In situ blood-perfused right ventricular papillary muscles of seven isolated Suga-Sagawa cross circulated canine hearts were studied with a servo system that clamped muscle length to produce isometric force, F(t), at one isometric length in each muscle at paced heart rates within the range 100–150. Each curve of F(t) was fitted, by Marquardt's algorithm, with the relation ![Formula][1] It was previously shown that the parameter B reflects changes in relaxation, whereas the parameters A and C reflect chronotropic and inotropic states. Changes in B reflect changes in the time course of relaxation that are not simply due to changes in total twitch duration guaranteed to be produced by altered heart rate. Linear regression analysis was performed on data from each muscle to determine whether each of the parameters A, B, and C changed significantly with heart rate. Results: The mean coefficient of determination, a measure of goodness of fit of the model to observed data, was 0.996(SD 0.001). With increase in heart rate, A and C increased significantly in six of the seven muscles. On the other hand B did not show significant change with heart rate in six of the seven muscles; in the seventh muscle, B increased significantly with heart rate. Similar results were obtained when other indices of lusitropy were used. Conclusion: Increase in heart rate does not impair myocardial lusitropy as measured by the parameter B which reflects changes in the time course of relaxation independent of change in total time course of mechanical activity. Cardiovascular Research 1994; 28 :92-99 [1]: /embed/graphic-1.gif
Measurement of Young's modulus on thin films under static and dynamic loading conditions

Measurement of Young's modulus of thin films is an important, yet challenging task. The purpose of this study, was to determine Young's modulus of an aluminum thin film using experimental data measured under static and dynamic loading conditions. The two test objects used in this study, a thin circular plate and a constant rectangular cross section cantilever beam, were constructed from an aluminum thin film. A nanoindenter was used to load the center of the thin circular plate, while simultaneously recording the applied force and displacement of the indenter tip. Then, using a basic equation relating the applied load and displacement to the geometry of the plate and its material properties, Young's modulus was determined. Using the experimental methods of electro-optic holography and laser vibrometry, the resonant frequency for the first bending mode of the cantilever beam was determined. Then, through an equation that relates the first resonant frequency to the material properties and the geometry of the cantilever beam. Young's modulus was determined. Uncertainty analyses of these basic equations, show that the uncertainty in Young's modulus is predominately affected by the measurement uncertainties of film thickness, and result, for the test samples used in this study, with uncertainties of 5 GPa for thickness errors on the order of 0.5 micrometers .© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Effects of fibroblast growth factor on type I 5'-deiodinase in FRTL-5 rat thyroid cells.

In the present study, we used FRTL-5 cells to study the effects of fibroblast growth factors (FGFs) on 5'-deiodinase (5'D) activity and messenger RNA (mRNA) levels. In FRTL-5 cells deprived of TSH for 7 days, type I 5'-deiodinase (5'D-I) activity decreased to low, but detectable levels. Incubation of cells with acidic and basic FGFs significantly decreased 5'D-I activity below the basal levels. After 7 days of TSH deprivation, the addition of TSH (100 microU/ml) to the medium for 3 days resulted in an increase in 5'D-I activity. This TSH-induced increase in 5'D-I activity was blocked by the FGFs in a dose-dependent manner. Kinetic analysis revealed that both acidic and basic FGFs decreased the maximum velocity of 5'D-I activity in the presence or absence of TSH, without any significant effect on the Km of enzyme binding. HPLC analysis of the products of the 5'D-I assay revealed that there was no sequential deiodination of rT3. Incubation of FRTL-5 cells with acidic or basic FGF did not affect basal cAMP c...
The Role of the Chest Radiograph in the Management of Childhood Asthma

Emergency Room records were analyzed retrospectively for 1548 asthma patient visits over a 24-month period. Chest x-rays were obtained during 391 visits. Five per cent had focal atelec tasis, ten per cent had a pulmonary infiltrate. There was no difference between the x-ray results of those children successfully treated as outpatients and those requiring hospitalization. Physicians frequently ordered x-rays for asthmatic children under 5 years of age, for those with temperature greater than 38.3 C, symptoms longer than 2 days, respiratory rate greater than 40, a more severe attack with asthma score greater than 3, or pulmonary rales. Significantly abnormal chest radio graphs (focal atelectasis or pulmonary infiltrate) were found only in patients under 5 years old or in older patients with pulmonary rales. The other patient characteristics which appeared to indicate a more severe asthma attack did not correlate with abnormal radiograph reports. The routine chest x-ray does not appear to provide useful info...
The intergranular segregation of boron in Ni3Al: Equilibrium segregation and segregation kinetics

Abstract The grain boundary B content of high-purity Ni-24 at.% Al alloys containing 0.048, 0.144, 0.240 and 0.480 at.% B (100, 300, 500, 1000 ppm mass) has been determined for samples aged from 1323 to 873 K for sufficient times to attain equilibrium. The B content was derived from Auger electron spectra of the intergranular fracture facets. Many facets were exposed during fracture at ≈ 300 K, and additional facets were formed upon fracturing following hydrogen charging after heat treatment. For each alloy sample, about 25 facets were analyzed. The grain boundary B contents were in the range of 0.5–2.5 at.%. The grain boundary B content increased with decreasing temperature and with increasing bulk B content in the alloys. The energy of binding of a B atom to the grain boundary was calculated using McLean's segregation theory and assuming a unique binding energy for each alloy. The values were in the range of 0.15–0.45 eV/atom, and increased with increasing temperature and with decreasing bulk B content. These results have been rationalized in terms of a spectrum of binding energies for a given alloy. However, when the entropy of adsorption was taken into account, an enthalpy of adsorption of B to the grain boundary of 0.13 eV/atom was obtained, independent of temperatire and bulk B content. This is interpreted to mean that the spectrum of binding energies is quite restricted. The grain boundary B content of these alloys has also been measured as a function of annealing time at 773, 873, 973 and 1173 K. The diffusion coefficient of B in Ni 3 Al at 773 K is about 5 × 10 −21 m 2 /s, and the equilibrium grain boundary B content is attained at about 3000 s. The diffusion coefficient at 973 K is between 10 −16 and 10 −17 m 2 /s. The activation energy for diffusion of B in Ni 3 Al is between 200,000 and 300,000 J/mol.
Comparison of direct numerical simulation of two-dimensional turbulence with two-point closure: the effects of intermittency

We compare results of high-resolution direct numerical simulation with equivalent two-point moment closure (the test-field model) for both randomly forced and spin-down problems. Our results indicate that moment closure is an adequate representation of observed spectra only if the random forcing is sufficiently strong to disrupt the dynamical tendency to form intermittent isolated vortices. For strong white-noise forcing near a lower-wavenumber cut-off, theory and simulation are in good agreement except in the dissipation range, with an enstrophy range less steep than the wavenumber to the minus fourth power. If the forcing is weak in amplitude, red noise, and at large wavenumbers, significant errors are made by the closure, particularly in the inverse-cascade range. For spin-down problems at large Reynolds numbers, the closure considerably overestimates enstrophy transfer to small scales, as well as energy transfer to large scales. We finally discuss the possibility that the closure errors are related to intermittency of various types. Intermittency can occur in either the inverse-cascade range (forced equilibrium) or the intermediate scales (spin-down), with isolated concentrations of vorticity forming the associated coherent structures, or it can occur in the dissipation range owing to the nonlinear amplification of variations in the cascade rate (Kraichnan 1967).
Coenzyme Q10 inhibits glutamate excitotoxicity and oxidative stress-mediated mitochondrial alteration in a mouse model of glaucoma.

Purpose. To test whether a diet supplemented with coenzyme Q10 (CoQ10) ameliorates glutamate excitotoxicity and oxidative stress–mediated retinal ganglion cell (RGC) degeneration by preventing mitochondrial alterations in the retina of glaucomatous DBA/2J mice.
Sizing swing check valves for stability and minimum velocity limits

Unexpected wear and failure of swing check valves cost power plants and water treatment facilities millions of dollars each year. Operating swing check valves at too low flow velocities can cause the check valve internals to rapidly wear and suddenly fail. Many of the swing check value failures could have been avoided by the use of a minimum velocity limit or a numerical model to predict the limit of minimum velocity limit or V[sub MIN] for swing check valves. The limit of V[sub MIN] is defined as the minimum flow velocity in which the valve disk is fully open and stable without motion. The procedures and equations can also be used to predict the velocity (V[sub OPEN]) to just open the disk to any position or angle. The equations presented in this paper are also unique in that they can be applied to swing check valves that have large degrees of disk position or value opening. The equations are not limited to swing check valves that must have a portion of the valve disk protruding into the flow through the check valve. Although the methodology was developed primarily for horizontal liquid flows, limited testing has shown that the equations canmore » be applied for installations with inclined slopes and for applications with compressible fluids. The following equations were derived from a large data base of tests of different sizes and types of swing check valves. Tables and figures are presented to support the suggested equations.« less
A Multidimensional Approach to the Study of the Structure of Coping with Stress

This article described a study in which the responses of 199 respondents to measures of coping with stress were submitted to multidimensional scaling. The three-dimensional solution suggests that respondents' perceptions of coping with stress are best explained along the following dimensions: (a) active coping versus denial/escape, (b) turning to interpersonal support versus seeking religious comfort, and (c) instrumental/cognitive disengagement versus affective/spiritual engagement.
Role of chordae tendineae in mitral valve opening: two-dimensional echocardiographic evidence

Abstract Study of 16 normal and 33 flail mitral valves provides evidence of the active participation of chordae tendineae in mitral valve opening. The normal valves have straight chordae at all phases of opening. During isovolumic relaxation and progressive opening phases, the smooth configuration of the mid-anterior mitral leaflet is broken by a sharp outward “tenting.” This tenting is localized at chordal insertions, reflecting significant tension at these points. Flail mitral valves allow comparison of opening motion between mitral segments with normal chordal attachment and flail segments without chordal support. Posterior flail leaflets demonstrate delay in initiation of opening motion relative to the normal anterior leaflet. The most dramatic examples of this delay reveal a maximal opening excursion of the anterior leaflet before the flail posterior leaflet initiates opening motion. The untethered free margins of opening flail anterior leaflets produce the appearance of the flail segment trailing the body of the anterior leaflet with a sharp break in leaflet contour between the supported and unsupported segments. These configurational expressions of mitral valve opening are inconsistent with a passive hemogenic mechanism. They support an active myogenic process mediated through direct traction on the valve by the chordae tendineae.