cssi/SciSciGPT-SciSciNet huggingface dataset:
SU‐E‐P‐14: Dosimetric Effects of Magnetic Field in MRI‐Guided Radiation Therapy Delivery for Breast Cancer

Purpose: MRI-guided radiation therapy (RT) delivery would be beneficial for breast irradiation. The electron return effect due to the presence of a transverse magnetic field (TMF) may cause dosimetric issues on dose on skin and at the lung-tissue interface. The purpose of this study is to investigate these issues. Methods: IMRT plans with tangential beams and VMAT plans with 200 degree arcs to cover ipsilateral breast were generated for 10 randomly selected breast cancer cases using a research planning system (Monaco, Elekta) utilizing Monte Carlo dose calculation with or without a TMF of 1.5 T. Plans were optimized to deliver uniform dose to the whole breast with an exclusion of 5 mm tissue under the skin (PTV-EVAL). All four plans for each patient were re-scaled to have the same PTV-EVAL volume to receive the same prescription dose. The skin is defined as the first 5 mm of ipsilateral-breast tissue, plus extensions in the surrounding region. Results: The presence of 1.5 T TMF resulted in (1)increased skin dose, with the mean and maximum skin dose increase of 5% and 9%, respectively; (2) similar dose homogeneity within the PTV-EVAL; (3) the slightly improved (3%) dose homogeneity in the whole breast; (4) Averagesmore » of 9 and 16% increases in V5 and V20, respectively, for ipsilateral lung; and (5) increased the mean heart dose by 34%. VMAT plans don’t improve whole breast dose uniformity as compared that to the tangential plans. Conclusion: The presence of transverse magnetic field in MRI-guided RT delivery for whole breast irradiation can Result in slightly improved dose homogeneity in the whole breast, increased dose to the ipsilateral lung, heart, and skin. Plan optimization with additional specific dose volume constraints may eliminate/reduce these dose increases. This work is partially supported by Elekta Inc.« less
Phosphatidylglycerol Flip-Flop Suppression due to Headgroup Charge Repulsion.

The kinetics and thermodynamics of 1,2-distearoyl-sn-glycero-3-[phospho(1′-rac-glycerol)] (DSPG) flip-flop in 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) membranes were examined by sum-frequency vibrational spectroscopy (SFVS). The effect of DSPG concentration in the membrane and the influence of electrolyte concentration were examined in an attempt to decipher the role the anionic PG headgroup plays in dictating the dynamics of PG flip-flop for this biologically important lipid species. DSPG flip-flop dynamics and the activation barrier to exchange were found to be directly dependent on the amount of DSPG present in the bilayer. Analysis of the activation free energy for DSPG flip-flop in mixed DSPG + DSPC bilayers reveals that charge repulsion between neighboring PG headgroups modulates the free energy barrier and subsequently, the rate of translocation. Specifically, when DSPG comprises a small portion of the bilayer, the electrostatic potential of neighboring PG lipids are effectively shielded f...
“Lyme”: Chronic Fatigue Syndrome by Another Name?

Clinical Infectious Diseases Advance Access published August 12, 2015 “Lyme”: Chronic Fatigue Syndrome By Another Name? Alan G. Barbour California Irvine cr ipt Departments of Medicine and Microbiology & Molecular Genetics, University of Corresponding Author: Alan G. Barbour, Microbiology and Molecular Genetics, University of California, Irvine, 3012 Hewitt, Irvine, CA 92697-4028, TEL: (949) 824- us an M pt ed ce Ac © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com. Downloaded from http://cid.oxfordjournals.org/ at University of California, Irvine on August 18, 2015 5626, FAX: (949) 824-8598, e-mail: abarbour@uci.edu
Substances Involved in Neurotransmission

This chapter discusses the substances involved in neurotransmission. All neurotransmitters are synthesized within the body, from precursors generally ingested during meals consumed as part of a normal diet. Thus, changes in levels of neurotransmitter precursors may, at least theoretically, change the amount of neurotransmitter substances synthesized by the cells. Even when sufficient amounts of precursors are present, a variety of other enzymes and related substances, collectively called second messengers, affects neurotransmitter synthesis. While some of these enzymes are also synthesized within the cells, others must cross the membrane in order to enter the cell, and molecules that regulate the permeability of cell membranes may affect the degree to which these substances can travel into the cell.
Experimental measurement of the drag coefficient.

The drag coefficient is related to the dissipative viscous force which acts on a dislocation in motion. The magnitude of the drag coefficient for a dislocation of known Burgers vector is determined by measurement of the viscous force at a known dislocation velocity, or by measurement of the energy dissipation brought about by the viscous force. We discuss here these measurements and explore the special conditions which make possible the determination of the drag coefficient.
Inducible expression of encephalomyocarditis virus 3C protease activity in stably transformed mouse cell lines.

Abstract An inducible expression vector system has been developed to facilitate the study of the effects of individual virus gene products on cell function. The vector utilizes the mouse metallothionein promoter carried on the bovine papillomavirus genome. Conditions which optimize the induced expression of open reading frames inserted downstream from the mouse metallothionein promoter have recently been described. In this communication we describe the use of this system to clone and express the encephalomyocarditis virus 3C protease in cultured mouse cells. Stably transformed cell lines could be induced to produce levels of 3C protease activity comparable to those observed during normal virus infection. In spite of this, no effects on cellular protein synthesis rate or membrane permeability were observed. It was also discovered that 3C protease as well as 3C protease-containing polyproteins are turned over. This was true not only in the induced cell clones, but also during the normal course of encephalomyocarditis virus infection, as well as in translation systems in vitro. This phenomenon was highly specific for this family of polypeptides, perhaps explaining their apparent lack of cytotoxic effects.
STEP: A Scalable Testing and Evaluation Platform

The emergence of online crowdsourcing sites, online work platforms, and evenMassive Open Online Courses (MOOCs), has created an increasing need for reliably evaluating the skills of the participating users in a scalable way.Many platforms already allow users to take online tests and verify their skills, but the existing approaches face many problems. First of all, cheating is very common in online testing without supervision, as the test questions often "leak" and become easily available online together with the answers.Second, technical skills, such as programming, require the tests to be frequently updated in order to reflect the current state-of-the-art. Third,there is very limited evaluation of the tests themselves, and how effectively they measure the skill that the users are tested for. In this paper, we present a Scalable Testing and Evaluation Platform (STEP),that allows continuous generation and evaluation of test questions. STEP leverages already available content, on Question Answering sites such as StackOverflow and re-purposes these questions to generate tests. The system utilizes a crowdsourcing component for the editing of the questions, while it uses automated techniques for identifying promising QA threads that can be successfully re-purposed for testing. This continuous question generation decreases the impact of cheating and also creates questions that are closer to the real problems that the skill holder is expected to solve in real life.STEP also leverages the use of Item Response Theory to evaluate the quality of the questions. We also use external signals about the quality of the workers.These identify the questions that have the strongest predictive ability in distinguishing workers that have the potential to succeed in the online job marketplaces. Existing approaches contrast in using only internal consistency metrics to evaluate the questions. Finally, our system employs an automatic "leakage detector" that queries the Internet to identify leaked versions of our questions. We then mark these questions as "practice only," effectively removing them from the pool of questions used for evaluation. Our experimental evaluation shows that our system generates questions of comparable or higher quality compared to existing tests, with a cost of approximately 3-5 dollars per question, which is lower than the cost of licensing questions from existing test banks.
Distributed fault detection via particle filtering and decision fusion

Due to the growing demands for system reliability and availability of large amounts of data, efficient fault detection techniques are desired. In this paper, we consider nonlinear, non-Gaussian systems monitored by multiple sensors. Normal and faulty behaviors can be modeled as two hypotheses. Due to the communication constraints, it is assumed that sensors can only send binary data to the fusion center. Under the assumption of independent, identically distributed observations, we propose a distributed fault detection algorithm, including local detector design and decision fusion rule design, based on the state estimation by particle filtering. Experimental results show the efficiency of our proposed algorithm and its superiority over the conventional Kalman filter-based methods.
The composition and origin of large microporphyritic chondrules in the Manych (L-3) chondrite

Abstract The majority (26/37) of the largest chondrules (d ≥ 1400 μm) exposed in a thin section of the Manych chondrite are more or less rounded fragments of microporphyry, most of which contain from 50 to 80 vol.% olivine. Modal and phase analyses were used to calculate the approximate bulk compositions of nine such chondrules. Six vary modestly around the mean composition of L-group chondrites less most of their metal and troilite and are thought to have formed by bulk melting of L-group material with loss of an immiscible Fe-Ni-S liquid. Two other chondrules, which are olivine-rich and Na- and Si-poor, formed in the same way but with some loss of volatile constituents to a vapor phase. The ninth chondrule, an olivine-poor microporphyry, may be a non-representative sample of a coarser microporphyritic rock. Comparison of these microporphyritic chondrules with the products of controlled cooling experiments and with chemically similar olivine microporphyry in the St. Mesmin chondrite (LL-breccia) suggests that the microporphyritic chondrules are fragments of magmatic rocks which crystallized from masses of liquid no less than 10 cm across.
Ascorbic acid transport by a clonal line of pheochromocytoma cells.

Abstract A clonal line of rat pheochromocytoma cells was used as a model of noradrenergic tissue to study ascorbic acid transport. These cells were used because, like sympathetic neurons, they synthesize large amounts of noradrenaline in the presence of ascorbate, they respond to nerve growth factor with the production of neurites and they release, store and take up catecholamines. In these cells, both with and without nerve growth factor (NGF) treatment, [ 14 C]ascorbic acid was concentrated by a stereospecific saturable, energy dependent transport system that could be described by a Michaelis-Menten transport—model. The K t and V max for ascorbic acid were approximately0.03m M and 0.3 nmole per min per mg protein respectively for both untreated and NGF-treated cells. The ability of the cells to concentrate ascorbic acid was not due to intracellular binding. Cells untreated with NGF and loaded with [ 14 C]ascorbic acid to a concentration of 5.6 nmoles per mg protein retained only 6% of the initial intracellular [ 14 C]ascorbic acid after the 24 h in normal growth medium. Thus, although pheochromocytoma cells contain an ascorbate concentrating system, optimal production of noradrenaline requires ascorbate in the medium.
Quantum scattering from a sinusoidal hard wall: Atomic diffraction from solid surfaces

An exact quantum formalism for atom scattering from a sinusoidal hard- wall surface is presented. The Lippmann-Schwinger equation is solved for a scattering kernel consistent with the hard-wall boundary conditions on the Schrodinger equation. It results in an infinite-dimensional matrix equation for the Fourier coefficients of the scattering kernel which can be solved in a finite- dimensional limit to convergence. The results show either rainbow or specular patterns depending on the surface roughness and incident k vector, as predicted by semiclassical and coupled-channel calculations. Bragg-like structure is present with the periodicity of the amplitude of the sinusoidal hard wall and the effects of multiple scattering are evidenced at large surface amplitudes. (AIP)
The effects of recoding and presentation format on recency and suffix effects

The primary linguistic theory of Shand and Klima (1981) hypothesizes that stimuli that cannot be directly processed without recoding are not in the primary linguistic mode of the subject and thus should lead to lesser recency and associated suffix effects. In three experiments, different normal hearing subjects learned to pair American Sign Language (ASL) stimuli, visual “quasivocables” (QVs), word-like letter strings, and auditory QVs with common English words. In the first experiment, the subjects were given sequences of ASL or QV stimuli and required to recall the associated words in strict serial order. In two other experiments involving auditory and visual presentation, respectively, subjects who had never been given paired associate training were required to recall the English words that had previously been associated with the ASL and QV stimuli, in a standard suffix paradigm. The results showed recency and suffix effects to be present only with auditorily presented QVs and words. Contrary to the predictions of the primary linguistic hypothesis, greater recency and larger suffix effects were present with the auditory QVs than with the auditory words, although the QVs were not primary linguistic and the task involved forced recoding. Previous results showing recency with ASL stimuli in normal subjects were not replicated. It is concluded that recency and suffix effects are not related either to the primary linguistic mode of the subject or to stimulus recoding, as we and Shand and Klima have defined them.
Design considerations for a medical school hospital cancer patient data system

Tumor registries abound, but there are few that successfully incorporate information age data management resources. This article describes the evolutionary process of designing, implementing, and maintaining a computer-based cancer patient information system for a medical school hospital. The primary requirement was that accurate information about the cancer experience at University of Texas Medical Branch (UTMB) be readily available. Since the tumor registry staff were not data processing professionals, this system had to use commonly available, well documented, readily maintained, and easily used data management resources. The UTMB registry, as documented by the marked increase in frequency and scope of use, demonstrates that a quality information resource can have a significant impact on hospital cancer programs and could serve as a prototype for other institutions having similar needs.
Glutathione in whole blood: a novel determination using double quantum coherence transfer proton NMR spectroscopy

Abstract Double quantum selective coherence transfer proton NMR spectroscopy has been used to observe glutathione in whole blood. The efficient water suppression of this technique avoids the need to resuspend the cells in D 2 O, hence avoiding equilibrium and kinetic isotope effects. Using this method we estimate the concentration of glutathione in fresh whole rabbit blood at ~1.7 mM.
Hybridization in the Mexican and 13-lined ground squirrels, Spermophilus mexicanus and Spermophilus tridecemlineatus.

Evidence of hybridization between the ground squirrels,Spermophilus tridecemlineatus andS. mexicanus is presented on the basis of chromosomal and protein data. The hybrids produced appear to be completely interfertile. Based on the evidence of hybridization and the recent reestablishment of contact between these two species, they are considered to be semispecies.
Apoprotein B quantification in rhesus and cynomolgus monkey atherosclerotic lesions.

Abstract The concept that much of the cholesterol deposition in atherosclerotic plaque development is provided by ingress of blood-derived apo B-rich lipoproteins into the arterial intima is given support by the study of arterial apo B accumulation. To compare the arterial wall level of immunoreactive apo B during the progression of diet-induced atherosclerosis in two widely used animal models of atherosclerosis, rhesus and cynomolgus monkeys were fed an atherogenic diet for 4, 8, and 12 months and their abdominal aortas quantitated for apo B. Apo B was extracted from aortic intima-media homogenates in two forms: Tris-buffer extractable or ‘loosely bound' and detergent (Triton X-100) extractable or ‘tightly bound'. The aortic extracts were quantitated for apo B by radial immunodiffusion, using goat antirhesus apo B along with serum LDL standards of the appropriate species diluted in the two extract solutions. The control monkeys' aortas contained only buffer-extractable apo B. The atherosclerotic aortas of both species of monkeys progressively increased their levels of loosely bound and tightly bound apo B through 4, 8, and 12 months of atherogenic diet feeding, with the 8- and 12-month cynomolgus aortas containing much larger amounts of apo B than the rhesus aortas. These differences in aortic apo B content could be accounted for by the greater rate at which the cynomolgus atherosclerotic lesions developed at the later time points. When the total lesion apo B levels were correlated with representative morphometrically-quantitated histopathologic sections of the homogenized aortas, a highly significant correlation was seen between the total aortic apo B values and both the absolute area of the intimal lesions and the total area of oil red O stainable lipid in the lesions ( P
Reducibilities on real numbers

The concept of reducibility in recursive function theory and computational complexity theory is applied to real numbers to investigate the notion of relative computability and relative complexity of real numbers. Several common types of reducibility such as Turing, truth-table and many-one reducibilities are considered. We also consider reducibilities defined by various sub-classes of recursive real functions. Some equivalence results among these reducibilities are obtained: The reducibility defined by recursive real functions is equivalent to the generalized truth-table redicibility; and the reducibility defined by recursive increasing real functions is equivalent to the generalized many-one reducibility. Similar equivalence results on polynomial time reducibilities are also proved. Different reducibilities are distinguished.
Global and variable cost manufacturing systems

Abstract The advent of global manufacturing companies has led to a series of new challenges and problems. One of the more important of these is planning capacity and facilities in the environment of exchange rate uncertainties. While exchange rate uncertainty is a feature of a global environment, the problem formulations actually apply to a wide range of facility and network design problems. This article presents a series of models and results to address these problems.
Use of Hymenal Measurements in the Diagnosis of Previous Penetration

Objective. To determine the usefulness of measurements of the vaginal opening and amount of hymenal tissue present inferiorly and laterally in the diagnosis of vaginal penetration. Methods. The transhymenal diameters and the amount of tissue present between the hymenal edge and vestibule inferiorly at 6 o’clock and laterally at 3 o’clock and 9 o’clock were measured from photographs of 189 prepubertal children with a validated history of digital or penile penetration and 197 children who denied previous sexual abuse. Statistical analyses were conducted to compare the mean values and hymenal symmetry between groups as well as to determine the sensitivity and specificity of various cutoff points. Results. Comparison of the mean diameters demonstrated that children with a penetration history had a significantly larger transverse opening than nonabused children when examined in the knee-chest position (5.6 vs 4.6 mm). However, there was extensive overlap in measurements between the 2 groups. No significant differences were noted between groups in the size of the vertical diameter, the amount of tissue present inferiorly or laterally, or the symmetry of the hymen in either position. Children with previous penetration were more likely than nonabused children to have a horizontal opening measuring >6.5 mm in the knee-chest position, but the sensitivity and specificity of this test were low (29% and 86%, respectively). Higher values had better specificity but very low sensitivity. Less than 1.0 mm of hymenal tissue was detected at 6 o’clock only in those with a history of penetration (100% specificity), but the sensitivity was low (1%–2%). Conclusion. Most hymenal measurements lack adequate sensitivity or specificity to be used to confirm previous penetration. Less than 1.0 mm of hymenal tissue at 6 o’clock was detected only in victims of abuse, but the usefulness of this test is limited by the rarity of this finding.
European union responses to AIDS/HIV and policy networks in the pre‐Maastricht era

Abstract The study of European public policy is attracting increasing attention. This article reviews the role which European Union‐wide networks have played in translating knowledge, experience and practices into a European Union Policy on AIDS/HIV in the pre‐Maastricht era. The article found three distinct types of network which have emerged in response to a variety of activities: macro‐policy development networks, research networks and community‐based networks. The weight of the evidence supports the argument that a distinctly ‘European policy style’ is emerging but it is not what one would expect from the literature on European integration, interest group politics or comparative politics or from some models of national policy‐making.
Abnormal differentiation of immunoregulatory T-lymphocyte subpopulations in the major histocompatibility complex (MHC) class II antigen deficiency syndrome.

The major histocompatibility complex (MHC) class II deficiency syndrome is a rare immunodeficiency disease associated with defective expression of class II MHC antigens. We have examined the consequences of this defect for the differentiation and functional capabilities of immunoregulatory T-cell subpopulations in an affected patient. Although the number of circulating T cells was normal, there was a striking reduction in the number of CD4+ T cells. Furthermore, purified CD4+ cells from the patient were unable to provide help for antibody secretion. This defect in helper function appeared to be due to the abnormal differentiation of the few CD4+ cells present, virtually all of which expressed the CD4 + HB11 + phenotype characteristic of immature “virgin” T cells. Abnormal development of immunoregulatory CD8+ T cells was also observed. Although increased numbers of CD8+ T cells were present, virtually none had phenotypic properties of suppressor cells (i.e., CD3+/CD8+/9.3-granular lymphocytes that coexpress the Leu-15 or Leu-7 antigens), and purified CD8+ cells from the patient had no suppressor activity. Thus, the absence of class II MHC antigens profoundly disrupts the development of immunoregulatory T cells. We propose that these effects occur by the following mechanisms: (1) the absence of intrathymic class II antigens results in deficient production of CD4+ cells, (2) the CD4+ cells that do emerge from the thymus do not undergo postthymic maturation into CD4+HB11- cells with helper capabilities, and (3) the absence of CD4+HB11- effector cells results in abortive development of suppressor cells involved in feedback suppression.
Endemic and Planned Corruption in a Monarchical Regime

Corruption may be defined in a legal or normative sense, and in some societies the two definitions may be coincident. In the legal sense, corruption is self-regarding behavior on the part of public functionaries that directly violates legal restrictions on such behavior. Normatively, a public functionary may be considered corrupt whedier or not a law is being violated in the process. A legally corrupt person may arouse no normative reprobation; a person judged corrupt by normative standards may be legally clean. What is common to both definitions is the notion of the abuse of public power and influence for private ends. It can safely be assumed that any society or political system manifests some level of one or the other, or both of these forms of corruption.
Slow Spin Relaxation in Two-Dimensional Electron Systems with Antidots

We report a Monte Carlo investigation of the effect of a lattice of antidots on spin relaxation in two-dimensional electron systems. The spin relaxation time is calculated as a function of geometrical parameters describing the antidot lattice, namely the antidot radius and the distance between their centers. It is shown that spin polarization relaxation can be efficiently suppressed by the chaotic spatial motion due to the antidot lattice. This phenomenon offers a new approach to spin coherence manipulation in spintronics devices.
Carbon dioxide in anaerobic spermatozoan metabolism.

Abstract The mechanism of CO 2 effects in mammalian spermatozoan metabolism is little understood. The demonstration of a need for CO 2 in anaerobic metabolism of epididymal-like bovine spermatozoa presented an opportunity for further study of CO 2 effects on glycolysis. A PCO 2 of 2 to 3% was optimum for maximum glycolysis, while levels above and below this narrow optimum range progressively depressed glycolysis. An initial PCO 2 of 1% or greater maintained spermatozoan motility, but lower levels did not. Sperm cells deprived of CO 2 for 2 hr or longer did not recover metabolism or motility when regassed with 5% CO 2 95% N2, whereas cells first subjected to 5% CO 2 demonstrated inhibited metabolism resulting from the removal of CO 2 only after the first hour. With fructose as substrate, a study of the addition of several substances revealed that only the complex material egg yolk replaced CO 2 in initiating glycolysis. Carbon dioxide was necessary for the anaerobic cellular conversion of pyruvate to lactate. The addition of NADH caused an early, marked uptake of CO 2 , which could be completely inhibited by γ -(3,4-urelenecyclohexyl) butyric acid, a biotin antagonist.
Prostaglandins in the uterus: modulation by steroid hormones.

Abstract Phospholipase A 2 (PLA 2 ), one of the enzymes considered to be rate-limiting in generating free arachidonic acid for prostaglandin (PG) synthesis, endogenous concentrations and in vitro production of PGs in the rat uterus were studied under various experimental conditions. Uterine PLA 2 activity showed a 167-fold increase in ovariectomized rats bearing estradiol-17 β (E 2 )-implants as compared to those treated with vehicle only. On the other hand, dexamenthasone treatment reduced the E 2 -stimulable PLA 2 activity by about 24-fold. The uterine PLA 2 activity in the ovariectomized rat uterus was low and not altered by instillation of progesterone (P 4 ) implants or by administration of dexamethasiome. On the contrary, simultaneously placement of E 2 - and P 4 -implants prevented significantly the rise in PLA 2 activity as observed under upposed E 2 exposure. Dexamethasome treatment further reduced the activity. The endogenous concentration of uterine PGF was several fold higher in the E 2 -implanted ovariectomized rats as compared to those without the E 2 -implants or carrying only P 4 -implants. The simulataneous treatment of the E 2 -implanted rats with P 4 and/or dexamethasone reduced the uterine PGF concentrations considerably. The uterine PGF concentration was always lower in the ovariectomized rats under any condition if they were not treated with E 2 . Uterine PGE-A concentration did not change significantly between the ovariectomized rats and the ovariectimized rats carrying E 2 -implants. The treatment with P 4 and/or dexamethasome, however, tended to decrease the PGE-A concentration. The production of PGF by the uterine homogenate increased by several fold in ovariectomized rats implanted with E 2 -silastic capsules as compared to those without the e 2 implants. The treatments of the E 2 -implanted rats with P 4 or dexamethasome did not alter this production. However, simultaneous exposure of E 2 -implanted rats to P 4 and dexamethasone lowered the production rate of PGF in the uterus. The treatment of the ovariectomized rats with dexanethasome or P 4 tended to elevate the uterine PGF production. The uterine PGE-A production followed more or less the same pattern. The analysis of our present data suggest that although a relationship exists between uterine PLA 2 activity and PGD concentration, the role of PG synthetase could also be important in regulating PGF synthesis. Our study with dexamethasome, which showed inhibition of uterine PLA 2 activity and decline in endogenous but not in vitro production of PGs, indicate that cellular integrity is essential for PLA 2 of function as a rate-limiting step in PG synthesis. The present findings also imply that alteration in PLA 2 or PG synthesis has little influence on PGE formation and the latter is not sensitive, to any great extent, to steroid hormonal changes. We considere that fluctuation in PGF/PGE ratio is mainly due to fluctuation in PGF level under various conditions.
A comparison of the effects of alkylation on the DNA of sensitive and resistant lettre-Ehrlich cells following in vivo exposure to nitrogen mustard.

Nitrogen mustard-sensitive and resistant Lettre-Ehrlich cells have been compared as to the effects of in vivo recovery on the DNA. It has been observed that: 1. 1. Both sensitive and resistant cells rapidly open cross-links and remove alkylated bases from their DNA, the rates being indistinguishable for the two cell strains. 2. 2. Both cell types preferentially excise N7-bis-diguaninyl alkylation products as compared to total as well as to N7-mono-guaninyl alkylations. 3. 3. Sensitive cells show a rapid and uncoordinated nicking of their DNA after alkylation and a failure to rejoin the broken ends. In contrast, resistant cells show a coordinated process of excision and repair. Our data, taken in conjunction with those of Walker I. G. and Reid, D. B. (1971) Cancer Res. 31, 510, suggest the existence of various repair deficiencies in mammalian cells, analogous to repair specific ligase and endonuclease deficiencies in microorganisms.
Square-free Lucas $d$-pseudoprimes and Carmichael-Lucas numbers

Let d be a fixed positive integer. A Lucas d-pseudoprime is a Lucas pseudoprime N for which there exists a Lucas sequence U(P, Q) such that the rank of N in U(P, Q) is exactly (N − e(N))/d, where e is the signature of U(P, Q). We prove here that all but a finite number of Lucas d-pseudoprimes are square free. We also prove that all but a finite number of Lucas d-pseudoprimes are Carmichael-Lucas numbers.
Hypoxia Increases Superoxide Anion Production from Bovine Coronary Microvessels, But Not Cardiac Myocytes, via Increased Xanthine Oxidase

Objective: To determine if 30 min of hypoxia (Po2 8–10 Torr) affects basal, mitochondrial, or xanthine oxidase-derived lucigenin-detectable superoxide anion (O2.-) production by intact isolated bovine coronary microvessels and myocytes.Methods: O2.- was quantitated by lucigenin-elicited chemiluminescence. Antimycin A (10 μM) and hypoxanthine (0.1 mM) were employed to increase O2.- from mitochondria and xanthine oxidase, respectively.Results: Chemiluminescence from microvessels and myocytes was enhanced (∼ twofold, P < 0.05, n = 8–10) by inhibition of Cu,Zn-SOD via pretreatment with diethyldithiocarbamate (10 mM, 30 min) and was decreased (P < 0.05, n = 8–10) by an intracellular scavenger of O2.- (10 mM Tiron), but not by added SOD (3 μM, n = 8–10). In the presence of SOD inhibition, hypoxia produced a hypoxanthine-dependent (n = 8–10) twofold increase in chemiluminescence (P < 0.05, n = 10) in microvessels but not in myocytes. Other combinations of hypoxia, antimycin, or hypoxanthine did not significantly...
Tumorigenic and mitogenic capacities are reduced in transfected fibroblasts expressing mutant insulin-like growth factor (IGF)-I receptors. The role of tyrosine residues 1250, 1251, and 1316 in the carboxy-terminus of the IGF-I receptor

Regulation of ligand-mediated signal transduction through transmembrane tyrosine kinase growth factor receptors involves phosphorylation of tyrosine residues in the intracellular domain of the receptor. The insulin-like growth factor-I (IGF-I) receptor contains three tyrosine residues in the carboxy-terminal domain at positions 1250, 1251, and 1316. Of these, only the tyrosine at position 1316 is conserved in the homologous position of the insulin receptor. Mutational analysis was used to study the role of these tyrosines in specific outcomes of IGF-I-mediated signal transduction. Mutations in the human IGF-I receptor were either replacement of tyrosines 1250 and 1251 with phenylalanine and histidine (yyFH), respectively, or replacement of the conserved distal tyrosine (position 1316) with phenylalanine (yCF). The yyFH mutation results in an IGF-I receptor with the amino acids found in the homologous position of the human insulin receptor. Cells overexpressing mutated IGF-I receptors were compared with ce...
Purification and characterization of a dipeptidase from Cucurbita maxima cotyledons

Abstract A dipeptidase has been isolated from Cucurbita maxima Duch, var. Hubbard cotyledons and purified nearly 2000-fold. The enzyme appeared to be specific for L -dipeptide hydrolysis. Although L -leucyl-glycine was hydrolyzed more rapidly than any other L -dipeptide investigated, all twelve L -dipeptides tested were hydrolyzed by this enzyme. D -dipeptides, tripeptides, aminoacid amides, chloroacetyldipeptides, tripeptide amides, proteins were not hydrolyzed by this dipeptidase. There was some indication of activation of L -leucylglycine hydrolysis by Mg ++ and Mn ++ and inhibition by EDTA, Zn ++ , and Co ++ . The pH optima was a broad one between 8·0 and 8·5. The dipeptidase activity with L -leucylglycine was stable to temperatures up to 85° and the activity changed very little between 25–50°. The Km value was 3·34 × 10 −1 M/1 with L -leucylglycine as the substrate at pH 7·6. This dipeptidase was different from the two aminopeptidases studied in our previous paper, and these aminopeptidases were removed during the purification.
Excursions of a normal random walk above a boundary

Abstract An integral condition is derived that is equivalent to the condition that the expected number of excursions by a normal random walk beyond a boundary is finite. In the case where the expected number of excursions is infinite, the asymptotic size is determined relative to the number of steps. Applications are given and the behavior for a transitional family of boundaries is investigated.
Cirrhosis with ascites: increased atrial natriuretic peptide messenger RNA expression in rat ventricle.

Abstract Background/Aims Atrial natriuretic peptides (ANPs) are increased in the circulation of cirrhotics with ascites; however, it is unknown whether this increase is caused by increased synthesis or a decrease in the metabolic processing of these peptides. ANP gene expression in the liver, atria, ventricles, and gastrointestinal tract of cirrhotic vs. control rats was studied as was their metabolism. Methods Sprague-Dawley rats developed cirrhosis with ascites approximately 20 weeks after weekly intragastric instillation of carbon tetrachloride. Their circulating, ascitic, and urinary levels of ANPs were measured by radioimmunoassays. ANP gene expression was measured by a ribonuclease protection assay. Results ANP gene expression was increased 2.8- to 4.1-fold in the ventricles of cirrhotic rats compared with age-matched healthy rats. ANP gene expression was present but not increased in the liver, atria, and gastrointestinal tract of cirrhotic rats. No increase of metabolic processing of these peptides was found in the circulation. Cardiac ultrasonography and catheterization revealed no ventricular dilation or increased ventricular pressure. Conclusions Elevation of circulating ANPs with cirrhosis was associated with increased ventricular steady-state ANP messenger RNA concentrations. The increased ANP gene expression in cirrhosis seems to involve a novel mechanism not related to stretch because neither increased ventricular pressure nor dilation was present.
Purification and biochemical characterization of the ATH1 gene product, vacuolar acid trehalase, from Saccharomyces cerevisiae

The disaccharide trehalose plays a critical role in yeast cell survival during conditions of environmental stress. The vacuole of the yeast Saccharomyces cerevisiae contains an enzyme, acid trehalose (ATH), that is capable of degrading trehalose. Recently, a gene required for ATH activity, ATH1, was cloned and sequenced [Destruelle et al., (1995) Yeast 11, 1015–1025]. The relationship between ATH1 and ATH, however, was not determined. We have purified ATH and shown that it is the ATH1 gene product; peptide sequences from the purified protein correspond to the deduced amino acid sequence of Ath1p. In addition, antiserum to Ath1p specifically recognizes purified ATH.
Sympathetic vasomotor changes induced by manual and electrical acupuncture of the hoku point visualized by thermography

Considerable evidence implicates sympathetic neural activity in acupuncture analgesia. However, the exact nature of these effects has not been specified in detail, and many experimental findings are contradictory. This study evaluated in normal conditions the specific sympathetic effects of both manual and electrical acupuncture applied to the same hand (Hoku) point. Thermographic measures of superficial skin temperature were used to assess sympathetic vasomotor tone in the face, hand and foot of 19 normal subjects. Baseline assessment, manual acupuncture and electrical acupuncture were performed in 3 separate sessions in a well controlled, 23 degrees C environment. Superficial skin temperature decreased slowly in the control condition. Both manual and electrical acupuncture produced a generalized long-lasting warming effect, indicating reduced sympathetic activity (sympatholytic effect). In addition, electrical acupuncture induced a localized short-term cooling effect, indicating a transient segmental increase in sympathetic activity (sympathomimetic effect).
Adaptations for viviparity in embryos and ovary of Anableps Anableps

In the Anablepidae, a family of viviparous Cyprinodont fishes, the mature eggs are fertilized in the ovarian follicles. The embryos are retained in the modified ovarian follicles until birth and are born when about 44 mm. in length. The embryos develop expanded yolk sacs which reach a maximal diameter of about 10. mm. The vitelline veins on the surface of the yolk sac develop rows of bead-like swellings, yolk sac bulbs, which serve to facilitate absorption of materials from the fluid of the follicle cavity. There is an extensive system of follicular villi upon the internal lining of the follicular capsule, the apparent function of which is to increase the vascular surface of the internal lining of the follicular capsule and to facilitate the interchange of materials between the blood of parent and fluid of the follicular cavity. The follicular villi and the yolk sac bulbs develop at the same time. These two adaptations for viviparity are apparently unique in this family of fishes.
Lectin binding patterns in diffuse large cell lymphoma.

The staining reaction of a panel of lectins in paraffin embedded lymph node specimens of diffuse large cell lymphoma was studied in relation to survival. In 47 of 49 patients, varying degrees of lectin binding were observed with Ricinus communis agglutinin (RCA), crude extract of Arachis hypogaea (c-PNA), Concanavalin ensiformis A (Con A), Triticum vulgaris A (WGA) and Phaseolus vulgaris A (PHA). Binding was either absent or only minimal with Pisum sativum A (PSA) and Lens culinaris A (LCA). Two categories of binding were observed: cell surface and cytoplasmic. Cell surface binding was seen in tumor cells, while cytoplasmic binding was observed in macrophage–histiocytes. Varying numbers of tumor cells were stained with RCA, WGA, c-PNA or PHA; but with Con A virtually no tumor cells were stained. Stromal macrophage–histiocytes were stained with RCA, WGA, or Con A in all but one case, frequently with all three lectins; c-PNA binding macrophage–histiocytes were absent in one third of the cases. With PHA the staining of stromal macrophage–histiocytes was extremely rare. Tumor cells that stained with RCA but not with c-PNA were observed in 9 of 15 patients who survived more than 2 years after diagnosis. In all 15 long-term survivors, stromal macrophage–histiocytes were positive for c-PNA. Tumor cells that reacted with c-PNA but not with RCA were seen in five patients who survived less than two years. All 16 patients whose tumors lacked c-PNA binding stromal macrophage–histiocytes in the presence of RCA binding macrophage–histiocytes were short-term survivors. These observations suggest the heterogeneity of stromal macrophage–histiocytes as well as that of tumor cells. Furthermore, the variation of lectin binding might be useful in assessing prognosis. Cancer 52:2089-2099, 1983.
An approximation of the relative real per capita GDP of the People's Republic of China☆

Abstract This paper presents a rough estimate of the real per capita GDP of the People's Republic of China, relative to that of the U. S. and other countries, with a 1975 reference date.
Bosonic quantum codes for amplitude damping

Traditional quantum error correction involves the redundant encoding of $k$ quantum bits using $n$ quantum bits to allow the detection and correction of any $t$ bit error. The smallest general $t=1$ code requires $n=5$ for $k=1$. However, the dominant error process in a physical system is often well known, thus inviting the following question: Given a specific error model, can more efficient codes be devised? We demonstrate alternative codes that correct just amplitude damping errors that allow, for example, a $t=1$, $k=1$ code using effectively $n=4.6$. Our scheme is based on using bosonic states of photons in a finite number of optical modes. We present necessary and sufficient conditions for the codes and describe construction algorithms, physical implementation, and performance bounds.
Viscous Flow in Glass‐to‐Metal Seals

Birefringence measurements were made on glass-to-metal seals with simple geometries during cooling at various rates. Thermal contraction data were also obtained on the metal and on the glass while cooling at the same rates. Using these data, the viscosity of the glass during cooling at a constant rate was calculated. The viscosity deviates markedly from the equilibrium curve and is a function of cooling rate in this temperature region. Viscous flow in the seal is measurable as much as 125°C. below the strain point.
Photoaging and Topical Tretinoin: Therapy, Pathogenesis, and Prevention

Repeated exposure to UV radiation from the sun causes premature skin aging. This photoaging is characterized by wrinkles, mottled pigmentations, dry and rough skin, and loss of skin tone. Since the clinical demonstration that the use of topical tretinoin can improve photoaged skin, a great deal of knowledge that may explain wrinkle effacement has been acquired. Central to this pursuit has been dermal collagen. In this article, we summarize evidence (mainly from humans) that implicates a deficiency of superficial dermal collagen as the cause of the dermal aspects of photoaging. In addition, a mechanism through which UV radiation can lead to reduced collagen is presented. Through our understanding of the pathophysiological mechanism of photoaging, our ability to treat and possibly prevent this skin condition is enhanced.
Functional Analysis of Genetic Variation in Catechol-O-Methyltransferase (COMT): Effects on mRNA, Protein, and Enzyme Activity in Postmortem Human Brain

Catechol-O-methyltransferase (COMT) is a key enzyme in the elimination of dopamine in the prefrontal cortex of the human brain. Genetic variation in the COMT gene (MIM 116790) has been associated with altered prefrontal cortex function and higher risk for schizophrenia, but the specific alleles and their functional implications have been controversial. We analyzed the effects of several single-nucleotide polymorphisms (SNPs) within COMT on mRNA expression levels (using reverse-transcriptase polymerase chain reaction analysis), protein levels (using Western blot analysis), and enzyme activity (using catechol methylation) in a large sample (n = 108) of postmortem human prefrontal cortex tissue, which predominantly expresses the -membrane-bound isoform. A common coding SNP, Val158Met (rs4680), significantly affected protein abundance and enzyme activity but not mRNA expression levels, suggesting that differences in protein integrity account for the difference in enzyme activity between alleles. A SNP in intron 1 (rs737865) and a SNP in the 3′ flanking region (rs165599)—both of which have been reported to contribute to allelic expression differences and to be associated with schizophrenia as part of a haplotype with Val—had no effect on mRNA expression levels, protein immunoreactivity, or enzyme activity. In lymphocytes from 47 subjects, we confirmed a similar effect on enzyme activity in samples with the Val/Met genotype but no effect in samples with the intron 1 or 3′ SNPs. Separate analyses revealed that the subject's sex, as well as the presence of a SNP in the P2 promoter region (rs2097603), had small effects on COMT enzyme activity. Using site-directed mutagenesis of mouse COMT cDNA, followed by in vitro translation, we found that the conversion of Leu at the homologous position into Met or Val progressively and significantly diminished enzyme activity. Thus, although we cannot exclude a more complex genetic basis for functional effects of COMT, Val is a predominant factor that determines higher COMT activity in the prefrontal cortex, which presumably leads to lower synaptic dopamine levels and relatively deleterious prefrontal function.
An unusual lignin from kenaf

A novel (possibly unique) lignin isolated from kenaf bast fibers had a high syringyl:guaiacyl ratio, was highly etherified, and was high in β-ether units with predominantly erythro stereochemistry. Moreover, it was extensively side-chain acetylated (primarily at γ), implicating 4-hydroxycinnamyl acetates as monomers in its biosynthesis.
An Upper Bound for the Length of a Finite-Dimensional Algebra☆

Abstract LetFbe a field, and letAbe a finite-dimensionalF-algebra. Writed = dimF A, and letebe the largest degree of the minimal polynomial for anya ∈ A. Define the function f(d, e) = e 2d/(e − 1) + 1/4 + e/2 − 2 . We prove that, ifSis any finite generating set forAas anF-algebra, the words inSof length less thanf(d, e) spanAas anF-vector space. In the special case ofn-by-nmatrices, this bound becomes f(n 2 , n) = n 2n 2 /(n − 1) + 1/4 + n/2 − 2 ∈ O(n 3/2 ) . This is a substantial improvement over previous bounds, which have all beenO(n2). We also prove that, for particular setsSof matrices, the bound can be sharpened to one that is linear inn. As an application of these results, we reprove a theorem of Small, Stafford, and Warfield about semiprime affineF-algebras.