cssi/SciSciGPT-SciSciNet huggingface dataset:
Mechanisms of Product Feedback Regulation and Drug Resistance in Cytidine Triphosphate Synthetases from the Structure of a CTP-Inhibited Complex†,‡

Cytidine triphosphate synthetases (CTPSs) synthesize CTP and regulate its intracellular concentration through direct interactions with the four ribonucleotide triphosphates. In particular, CTP product is a feedback inhibitor that competes with UTP substrate. Selected CTPS mutations that impart resistance to pyrimidine antimetabolite inhibitors also relieve CTP inhibition and cause a dramatic increase in intracellular CTP concentration, indicating that the drugs act by binding to the CTP inhibitory site. Resistance mutations map to a pocket that, although adjacent, does not coincide with the expected UTP binding site in apo Escherichia coli CTPS [EcCTPS; Endrizzi, J. A., et al. (2004) Biochemistry 43, 6447-6463], suggesting allosteric rather than competitive inhibition. Here, bound CTP and ADP were visualized in catalytically active EcCTPS crystals soaked in either ATP and UTP substrates or ADP and CTP products. The CTP cytosine ring resides in the pocket predicted by the resistance mutations, while the triphosphate moiety overlaps the putative UTP triphosphate binding site, explaining how CTP competes with UTP while CTP resistance mutations are acquired without loss of catalytic efficiency. Extensive complementarity and interaction networks at the interfacial binding sites provide the high specificity for pyrimidine triphosphates and mediate nucleotide-dependent tetramer formation. Overall, these results depict a novel product inhibition strategy in which shared substrate and product moieties bind to a single subsite while specificity is conferred by separate subsites. This arrangement allows for independent adaptation of UTP and CTP binding affinities while efficiently utilizing the enzyme surface.
Molecular markers associated with the immature fiber (im) gene affecting the degree of fiber cell wall thickening in cotton (Gossypium hirsutum L.).

Cotton fiber fineness and maturity measured indirectly as micronaire (MIC) are important properties of determining fiber grades in the textile market. To understand the genetic control and molecular mechanisms of fiber fineness and maturity, we studied two near isogenic lines, Gossypium hirsutum, Texas Marker-1 wild type (TM-1) and immature fiber (im) mutant showing a significant difference in MIC values. The fibers from im mutant plants were finer and less mature with lower MIC values than those from the recurrent parent, TM-1. A comprehensive fiber property analysis of TM-1 and im mutant showed that the lower MIC of fibers in im mutant was due to the lower degree of fiber cell wall thickening as compared to the TM-1 fibers. Using an F2 population comprising 366 progenies derived from a cross between TM-1 and im mutant, we confirmed that the immature fiber phenotype present in a mutant plant was controlled by one single recessive gene im. Furthermore, we identified 13 simple sequence repeat markers that were closely linked to the im gene located on chromosome 3. Molecular markers associated with the im gene will lay the foundation to further investigate genetic information required for improving cotton fiber fineness and maturity.
Relationship between placental blood flow resistance and precordial venous Doppler indices

Objective To characterize the relationship between placental blood flow resistance and precordial venous Doppler indices in normal fetuses. Methods This was a prospective cross-sectional Doppler study of uncomplicated pregnancies. Umbilical artery (UA), inferior vena cava (IVC) and ductus venosus (DV) were examined. Multiple indices were calculated for each vein and correlated with the UA pulsatility index (PI) and gestational age (GA). In addition, an arteriovenous ratio (AV ratio) between the UA PI and multiple venous indices was calculated and related to GA. Results In the 237 patients studied all venous indices showed a linear relationship with the UA PI. All venous indices except the IVC preload index (PLI) had a significant positive correlation with the UA PI. Seven AV ratios were calculated and each had a linear negative relationship with GA. The relationship between UA PI and IVC pulsatility index for veins (PIV) and DV PIV remained constant throughout gestation. The AV ratio that utilized the IVC PLI and DV systolic/a-wave ratio showed a significant decline with GA. Conclusion Placental blood flow resistance least influences the IVC PLI while the converse is true for the PIV in both veins. A differential effect of placental afterload on various venous indices needs to be accounted for in situations of elevated placental blood flow resistance. AV Doppler ratios may be useful for this purpose. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
An application of Thompson's typology to TQM in service firms

Abstract This work is based on the premise that service firms are different. The involvement of customers in the provision of services not only creates an uncertainty that makes service organizations different from manufacturing firms, but, within the broad classification of service organizations, they can also be different from each other. In line with previous research on service firms, we use Thompson's [Thompson, J.D. (1967). Organizations in action. New York: McGraw-Hill] typology of interdependence (pooled, sequential, and reciprocal) as a useful framework for addressing those differences. We deduce that components of TQM content and TQM process should vary according to an organization's degree of interdependence if output uncertainty, expressed in terms of service quality, is to be minimized. Thus, the success of TQM in service organizations is dependent upon the fit among interdependence and the strategy's content and process.
Higher-order unification via combinators

Abstract We present an algorithm for unification in the simply typed lambda calculus which enumerates complete sets of unifiers using a finitely branching search space. In fact, the types of terms may contain type variables, so that a solution may involve type-substitution as well as term substitution. The problem is first translated into the problem of unification with respect to exstensional equality in combinatory logic, and the algorithm is defined in terms of transformations on systems of combinatory terms. These transformations are based on a new method (itself based on systems) for deciding extensional equality between typed combinatory logic terms.
The interstellar absorption-line spectrum of Mu Ophiuchi

UV interstellar lines have been measured on high-resolution, long- and short-wavelength IUE spectra of the B8 V star Mu Oph. Column densities for the observed atoms and ions have been determined as well as turbulent velocities. The interstellar spectrum of Mu Oph is similar to the ones for Rho Oph and Zeta Oph. The ionization equilibria of several elements give consistent limits for the electron density. The C I line arising from different fine-structure levels are studied to yield estimates on the physical conditions in the cloud. Relative depletion of elements in the cloud seen in the interstellar spectrum of Mu Oph follows the same pattern as seen in the interstellar spectra of Zeta Oph and six other stars in the Rho Oph cloud complex.
The effect of escapable versus inescapable social defeat on conditioned defeat and social recognition in Syrian hamsters

Male Syrian hamsters are naturally aggressive animals that reliably defend their home territory against intruding conspecifics. Hamsters that lose agonistic encounters subsequently exhibit a striking change in their agonistic behavior, however, expressing no aggression and instead becoming highly submissive, a behavioral change that we have termed conditioned defeat. We have generally employed an inescapable defeat training protocol when studying conditioned defeat. The purpose of the present study was to determine if conditioned defeat is an epiphenomenon of the inescapable defeat experience by comparing the behavior of hamsters exposed to inescapable versus escapable defeat. In the conditioned defeat model, defeated hamsters subsequently generalize their submission and social avoidance to a novel, non-aggressive opponent, suggesting that hamsters subjected to inescapable defeat may not form a specific memory of their aggressive opponent. Thus, a secondary purpose of the present study was to determine whether hamsters subjected to our defeat protocol have the ability to recognize a familiar opponent following defeat. Our results provide evidence that conditioned defeat is not solely a by-product of inescapable defeat because all experimental animals, regardless of the type of defeat, expressed conditioned defeat during testing. We also found that animals experiencing an inescapable defeat avoided a familiar aggressor significantly more than they did an unfamiliar aggressor, demonstrating that these animals have the ability to recognize their previous attacker. Thus, we maintain that a variety of social defeat models, and conditioned defeat in particular, represent generalizable and ethologically valid models with which to study the effects of social stress on physiology and behavior.
On the complexity of finite, pushdown, and stack automata

The complexity of predicates on several classes of formal languages is studied. For finite automata, pushdown automata, and several classes of stack automata, every nontrivial predicate on the languages accepted by the 1-way devices requires as much time and space as the recognition problem for any language accepted by the corresponding 2-way devices. Moreover there are nontrivial predicates on the languages accepted by the 1-way devices such that is the accepted language of some corresponding one or two head 2-way device. Thus our lower bounds are fairly tight.
On the polyhedral complexity of the integer points in a hyperball

Let B^n be a hyperball in R^n, n>=2, and denote B"Z^n=B^[email protected]?Z^n. Define polyhedral facet complexity of B"Z^n as FC(B"Z^n)=min"P{f"n"-"1(P)} where P is an enclosing polyhedron for B"Z^n (i.e., P"[email protected]?Z^n=B"Z^n) and f"n"-"1(P) is the number of the (n-1)-facets of P. Analogously, define polyhedral vertex complexity of B"Z^n as VC(B"Z^n)=min"P{f"0(P)} where P is an enclosing polyhedron for B"Z^n and f"0(P) is the number of the 0-facets (vertices) of P. Upper bounds for FC(B"Z^n) follow from a well-known bound for the number of facets and vertices of the convex hull of B"Z^n [I. Barany, D.G. Larman, The convex hull of the integer points in a large ball, Math. Ann. 312 (1998) 167-181]. In this note we provide the first nontrivial lower bounds on FC(B"Z^n) and VC(B"Z^n).
Cultural aspects of suicide: The case of Japanese oyako shinj[ubar] (parent-child suicide)

Abstract The psychocultural view of suicide deals with it in terms of an interaction between personality and environment, especially the social resources available for the individual. Social resources are environmental factors that the individual can use for his tension-reduction and problem-solving. That social resources and personality are involved in Japanese suicide is illustrated by oyako shinj[ubar] (“parent-child suicide” in Japan; “murder-suicide” in the United States). It is concluded that social meanings attached to self-destructive behaviour is understandable only by personological, contextualized approaches to suicide.
Quantifying the literature of computer-aided instruction in medical education.

ABSTRACTPurposeTo characterize the literature about computer-aided instruction (CAI) as it relates to medical education.MethodA descriptive study using the Medline and ERIC databases, reviewing articles pertaining to CAI for medical professionals. The literature was evaluated with respect to type of
How and why young adults do and do not search for health information: Cognitive and affective factors:

Objective:The goal of this study was to take an in-depth look at why college students do (or do not) seek health information, and how they seek information when they do.Design:Qualitative content a...
Oxygen-regulated expression of the Wilms' tumor suppressor Wt1 involves hypoxia-inducible factor-1 (HIF-1).

SPECIFIC AIMSWe recently reported de novo expression of the Wilms’ tumor suppressor Wt1, a critical molecule for development of the heart and genitourinary system, in blood vessels of the ischemic myocardium. The purpose of this study was to analyze the mechanism(s) of hypoxic/ischemic induction of Wt1 and to assess the potential impact of oxygen-regulated Wt1 expression.PRINCIPAL FINDINGS1. Wt1 mRNA in normoxic and hypoxic organsRNase protection assay was used to measure Wt1 mRNA in various organs of rats exposed at normal atmosphere (20% O2) or at normobaric hypoxia (8% O2). Hypoxic exposure increased Wt1 transcripts in the kidneys and heart on average 3.3- and 2.3-fold (n=5, each) compared with rats at normoxia (20% O2). A significant increase of Wt1 mRNA was detectable after 2 h of oxygen restriction and could be mimicked by exposure at 0.1% carbon monoxide. No differences in Wt1 mRNA were found in the brain and spleen of normoxic and hypoxic rats.2. Wt1 is expressed de novo in the tubules of hypoxic ...
Extreme events in a changing climate: Variability is more important than averages

Extreme events act as a catalyst for concern about whether the climate is changing. Statistical theory for extremes is used to demonstrate that the frequency of such events is relatively more dependent on any changes in the variability (more generally, the scale parameter) than in the mean (more generally, the location parameter) of climate. Moreover, this sensitivity is relatively greater the more extreme the event. These results provide additional support for the conclusions that experiments using climate models need to be designed to detect changes in climate variability, and that policy analysis should not rely on scenarios of future climate involving only changes in means.
Comment on the model for isothermal oscillations of ethylene oxidation on platinum

From a study of the governing equations of Vayenas et al model, these authors report that the mathematical model does not actually produce observable limit cycles. There is agreement that catalytic activity variations due to thermodynamic stability of a new phae may be the key mechanism for osciallations in this system and other oxidation reactions on noble metals. The differences in results are explained by the large time step sizes assumed in the Euler calculations. 1 table.
Correlation of Endothelin-1 and Transforming Growth Factor β1 with Malignancy and Vascularity in Human Gliomas

Because the prominent neovascularization characteristic of high grade primary brain tumors is composed mostly of vascular smooth muscle cells (VSMC), we studied the expression of the potent smooth muscle mitogen endothelin-1 (ET-1) and one of its secretagogues, transforming growth factor β1 (TGF-β1) in a series of astrocytic tumors. TGF-β1 is also of interest due to its known activity as an angiogenic factor. Using immunohistochemical methods, we examined 30 surgical cases: 10 glioblastoma multiforme, 10 anaplastic astrocytomas, and 10 low-grade astrocytomas. Using a monoclonal antibody to TGF-β1 and a polyclonal antibody to ET-1, we detected both growth factors in all cases of glioblastoma examined. In cases of anaplastic astrocytoma, 4 tumors were positive for both factors; 2 contained only ET-1; 2 contained only TGF-β1; and 2 exhibited no tumor cell immunoreactivity for either factor. In low-grade astrocytoma, 4 of 10 tumors showed weak ET-1 immunoreactivity; 2 of those contained TGF-β1 immunopositive tumor astrocytes; 6 tumors were negative for both factors. In all tumors that expressed both factors, serial sections showed that regions of ET-1 immunopositivity also tended to be positive for TGF-β1. Endothelial cells within all tumors were positive for ET-1. ET-1 and TGF-β1 are present in human astrocytomas and their expression correlates with tumor vascularity and malignancy. These results suggest roles for both ET-1 and TGF-β1 in the growth and progressive angiogenesis of the human glioma.
Plasmalogens, phospholipase A2, and docosahexaenoic acid turnover in brain tissue

Plasmalogens are glycerophospholipids of neural membranes containing vinyl ether bonds. Their synthetic pathway is located in peroxisomes and endoplasmic reticulum. The rate-limiting enzymes are in the peroxisomes and are induced by docosahexaenoic acid (DHA). Plasmalogens often contain arachidonic acid (AA) or DHA at the sn-2 position of the glycerol moiety. The receptor-mediated hydrolysis of plasmalogens by cytosolic plasmalogen-selective phospholipase A2 generates AA or DHA and lysoplasmalogens. AA is metabolized to eicosanoids. The mechanism of signaling with DHA is not known. The plasmalogen-selective phospholipase A2 differs from other intracellular phospholipases A2 in molecular mass, kinetic properties, substrate specificity, and response to glycosaminoglycans, gangliosides, and sialoglycoproteins. A major portion of [3H]DHA incorporated into neural membranes is found at the sn-2 position of ethanolamine glycerophospholipids. Studies with a mutant cell line defective in plasmalogen biosynthesis indicate that the incorporation of DHA is reduced in this RAW 264.7 cell line by 50%. In contrast, the incorporation of AA remains unaffected. This is reversed completely when the growth medium is supplemented with sn-1-hexadecylglycerol, suggesting that DHA can be selectively targeted for incorporation into plasmalogens. We suggest that deficiencies of DHA and plasmalogens in peroxisomal disorders, Alzheimer's disease (AD), depression, and attention deficit hyperactivity disorders (ADHD) may be responsible for abnormal signal transduction associated with learning disability, cognitive deficit, and visual dysfunction. These abnormalities in the signal-transduction process can be partially corrected by supplementation with a diet enriched with DHA.
Line-graphs of cubic graphs are normal

A graph is called normal if its vertex set can be covered by cliques Q"1,Q"2,...,Q"k and also by stable sets S"1,S"2,...,S"l, such that S"[email protected]?Q"j @A for every i,j. This notion is due to Korner, who introduced the class of normal graphs as an extension of the class of perfect graphs. Normality has also relevance in information theory. Here we prove, that the line graphs of cubic graphs are normal.
Reconstitution of a Functional Bovine Papillomavirus Type 1 Origin of Replication Reveals a Modular Tripartite Replicon with an Essential AT-Rich Element

A functional replication origin was reconstituted using oligonucleotide cassettes corresponding to three sequence subelements within the Bovine Papillomavirus Type 1 (BPV-1) replication origin: the 23-bp AT-rich region (ATR), the 18-bp binding site for the viral replication initiator protein E1 (E1BS), and a binding site for the viral transcriptional transactivator and replication enhancer protein E2 (E2BS). Replication of the reconstituted origin depended on heterologous expression of both the E1 and E2 proteins and on the presence of both the E1BS and E2BS, indicating that it is functionally analogous to the authentic BPV-1 origin. In addition, pairwise testing of subelement combinations revealed that the ATR was also essential and that a functional origin required at least one copy of all three subelements. While the E1BS and E2BS are sequence-specific elements, the function of the BPV-1 ATR could be at least partially substituted with heterologous AT-rich sequences, suggesting that the role of this element is primarily AT content-dependent rather than sequence-dependent. A stringent requirement for the ATR was also observed in the context of an authentic minimal origin sequence confirming that it is an intrinsic property of the BPV-1 origin and not simply an artifact of the reconstitution system. This study indicates that the minimal functional BPV-1 origin shares the tripartite modular organization characteristic of other simple eukaryotic replication origins. The reconstitution system described now provides a convenient approach to define the physical and functional interrelationships between the three subelements in a systematic fashion.
The 17th Annual Intelligent Ground Vehicle Competition: intelligent robots built by intelligent students

The Intelligent Ground Vehicle Competition (IGVC) is one of four unmanned systems student competitions that were founded by the Association for Unmanned Vehicle Systems International (AUVSI). The IGVC is a multidisciplinary exercise in product realization that challenges college engineering student teams to integrate advanced control theory, machine vision, vehicular electronics and mobile platform fundamentals to design and build an unmanned ground vehicle. Teams from around the world focus on developing a suite of dual-use technologies to equip their system of the future with intelligent driving capabilities. Over the past 17 years, the competition has challenged undergraduate, graduate and Ph.D. students with real world applications in intelligent transportation systems, the military and manufacturing automation. To date, teams from over 70 universities and colleges have participated. This paper describes some of the applications of the technologies required by this competition and discusses the educational benefits. The primary goal of the IGVC is to advance engineering education in intelligent vehicles and related technologies. The employment and professional networking opportunities created for students and industrial sponsors through a series of technical events over the four-day competition are highlighted. Finally, an assessment of the competition based on participation is presented.
Maturation of Jejunal Phosphate Transport by Rat Brush Border Membrane Vesicles

ABSTRACT: The transport of phosphate into jejunal brush border membrane vesicles isolated from 14- to 42- day-old rats was investigated using a rapid filtration technique. The presence of a sodium gradient enhanced phosphate uptake at all ages. Both sodium-dependent phosphate uptake and passive phosphate uptake declined with increasing age. The activity of the sodium/phosphate cotransporter was significantly greater in the 14-day-old suckling animals than in the 42-day-old animals. Experiments with valinomycin in 14- and 42-day-old animals showed that at pH 7.4, phosphate uptake is electroneutral at both ages. These findings demonstrate there are maturational changes in the jejunal transport of phosphate. Suckling animals transport significantly more phosphate than adult animals. The increased uptake in the younger animals is related to an increase in the active uptake of phosphate and an increase in the passive permeability to phosphate.
Relating laboratory and outdoor exposure of coatings: II. Effects of relative humidity on photodegradation and the apparent quantum yield of acrylic-melamine coatings

The effect of relative humidity (RH) from ≪1% to 90% on the photodegradation and quantum efficiency for a partially-methylated melamine acrylic coating exposed to UV/50°C condition has been investigated. The UV source is supplied by two 1000 W Xenon arc solar simulators and the relative humidities are provided by specially designed humidity generators, which control relative humidity in the 0 to 90% range to within <3% of the measured values. Radiation absorbed in the coating and degradation of the films are measured by UV-visible and Fourier transform infrared spectroscopies, respectively. The degradation at a particular RH/UV condition consists of four different modes: reactions taken place during post curing, hydrolysis due to water in the film at a particular RH, photodegradation, and moisture-enhanced photodegradation. Total degradation, hydrolysis, and moisture-enhanced photodegradation increase with increasing RH. At low relative humidities, photodegradation is an important degradation mode but hydrolysis dominates the degradation at high RH levels. Moisture in the film is found to increase the quantum efficiency of acrylic melamine coating photodegradation.
Removal of the vomeronasal organ reduces reproductive performance and aggression in male prairie voles

Several short-duration tests have demonstrated that the surgical removal of the vomeronasal organ (VNX) from sexually-inexperienced male rodents results in a reduction in copulatory behavior, compared to the effects of sham surgery (SHAM). We extended these studies to adult male prairie voles, Microtus ochrogaster, and substantially increased the duration of the tests. During the initial interactions with females, VNX males spent significantly less time with their noses in close proximity to the females than did SHAM males. Moreover, only two of nine VNX males sired offspring after having been paired with females for 8 weeks, whereas nine of 12 SHAM males sired offspring in that interval. We also found that VNX and SHAM males were equivalently non-aggressive to an anesthetized stimulus-male prior to being paired with females. However, after spending 2 weeks paired with a female, the VNX males were significantly less aggressive than were the SHAM males, possibly as a result of having copulated less often. In a later test, nearly all of the VNX and SHAM males that sired offspring were vigorously aggressive to a stimulus male. We conclude that the stimulation of the vomeronasal system in sexually-inexperienced male prairie voles is important for maximal reproductive performance and that the VNX-induced impairment in reproduction is associated with a decrease in inter-male aggression. The possible sensory effects of the vomeronasal system on the neural and endocrine control of reproduction and behavior are discussed.
Refractive abnormalities in childhood.

Every pediatric practice includes many patients with refractive problems. Some of these problems pose a serious threat to vision, others significantly affect performance or comfort but cause no lasting harm, and many have little or no impact on the child's life. Some are likely to need lifelong attention, whereas others represent an active concern only for a few years. Some require that the child wear glasses full time; others permit correction on a part-time or discretionary basis. This article helps make sense of these varied, important, and much misunderstood disorders.
Intra-chromosomal rearrangements generated by Cre-lox site-specific recombination

Chromosomal rearrangements are useful genetic and breeding tools but are often difficult to detect and characterize. To more easily identify and define chromosome deletions and inversions, we have used the bacteriophage P1 Cre-lox site-specific recombination system to generate these events in plants. This involves three steps: (i) the introduction of two lox sites into one locus in a plant genome, including one site within a modified Ds transposon; (ii) Ac transposase-mediated transposition of the Ds-lox element to a new locus on the same chromosome; (iii) Cre-mediated site-specific recombination between the two lox sites that bracket a chromosome segment. We report the production of a deletion and three inversion events in tobacco. The utility of chromosomal segments bracketed by lox sites for targeted manipulation and cloning is discussed.
The structure of multilayered titania nanotubes based on delaminated anatase

Abstract We constructed a truly nanotubular structure model of titania nanotubes based on delaminated anatase with realistic dimensions replicating those observed in experiments. It is shown that this nanotubular structure based on delaminated anatase produces an XRD pattern in excellent agreement with the observed spectrum and that the tube axis is along the [0 1 0] direction of the anatase structure. Preserving the atomic registry of delaminated anatase between adjacent layers is essential along the tube axis but unnecessary along the circumference. These understandings provide detailed information on the structure and morphology of hydrothermally synthesized titania nanotubes. The findings will help discern the complex surface chemistry of these materials.
A Meta-Analytic Review of the Dark Triad-Intelligence Connection

Abstract We conducted a meta-analytic review of the relations between general mental ability (GMA) and the Dark Triad (DT) personality traits—Machiavellianism, narcissism, and psychopathy—to determine if individuals who display socially exploitative social qualities tend to be more intelligent or less intelligent. Across 48 independent samples, GMA showed no consistent relation with any DT trait. These effects were not sufficient to support either the “evil genius” hypothesis (highly intelligent individuals tend to display socially exploitative personality traits) or the “compensatory” hypothesis (less intelligent individuals compensate for their cognitive disadvantages by adopting manipulative behavioral tendencies). However, these relations were moderated, to some extent, by the sex and age of the participants, type of sample studied, and the measure of GMA.
Management of enterocutaneous fistulas.

Management of enterocutaneous fistulas (ECFs) involves (1) recognition and stabilization, (2) anatomic definition and decision, and (3) definitive operation. Phase 1 encompasses correction of fluid and electrolyte imbalance, skin protection, and nutritional support. Abdominal imaging defines the anatomy of the fistula in phase 2. ECFs that do not heal spontaneously require segmental resection of the bowel segment communicating with the fistula and restoration of intestinal continuity in phase 3. The enteroatmospheric fistula (EAF) is a malevolent condition requiring prolonged wound care and nutritional support. Complex abdominal wall reconstruction immediately following fistula resection is necessary for all EAFs.
High-performance liquid chromatography—continuous-flow fast atom bombardment mass spectrometry of chlorophyll derivatives

Abstract Nine chlorophyll derivatives from different spinach preparations were separated and identified using reversed-phase high-performance liquid chromatography—mass spectrometry (HPLC—MS). These pigments included chlorophylls a and b, chlorophyllides a and b, pheophorbide a, pheophytins a and b, and pyropheophytins a and b. HPLC—MS measurements were carried out using HPLC—frit-fast atom bombardment (FAB)-MS, which is a continuous-flow FAB-MS interface. The highly hydrophobic chlorophyll derivatives were eluted from a reversed-phase HPLC column using a gradient of increasing ethyl acetate concentration. Glycerol was included in the mobile phase to serve as the matrix for FAB ionization. During analysis by positive-ion HPLC—frit-FAB-MS, abundant protonated molecules, [M + H]+ were detected for all nine chlorophyll derivatives. Fragment ions were observed in the mass spectra that were similar to those produced during standard probe FAB-MS. These HPLC—MS procedures were shown to be useful for the rapid separation and identification of a variety of chlorophyll derivatives from natural sources.
Exploring Quasi-Concurrency in Introductory Computer Science

Most programming courses taught today are focused on managing batch-oriented problems. It is primarily because parallel computers are not commonly available, therefore problems with concurrent nature could not be explored. This consequence, at the same time, causes student's under preparation to meet the challenge of modern multi-process computation technologies. This article demonstrates an easy solution for implementing concurrent programming projects in computer labs. This solution does not require special hardware support or special programming languages. The goal is to facilitate a means to deal with the concept and usefulness of multi-process software systems in the early stage of computer science curriculum. We also include detailed descriptions on a few creative and interesting concurrent examples to illustrate this idea.
Nanofluidic ionic diodes. Comparison of analytical and numerical solutions.

Recently reported experimental and theoretical studies of nanofluidic nonlinear devices, such as bipolar and unipolar ionic diodes, have yet to answer the question about the possibility of their further miniaturization. In this Article, we theoretically investigate the effects of size reduction, applied bias, and solution ionic strength in such devices. We compare the numerical solutions of the Poisson, Nernst−Planck (PNP), and Navier−Stokes (NS) equations with their one-dimensional, analytical approximations. We demonstrate that the contribution of electroosmosis is insignificant and find analytical approximations to PNP for bipolar and unipolar diodes that are in good agreement with numerical 3D solutions. We identify the minimal dimensions for such diodes that demonstrate ion current rectification behavior and demonstrate the importance of the edge effect in very short diodes.
Phonon-limited and effective low-field mobility in n- and p-type [100]-, [110]-, and [111]-oriented Si nanowire transistors

Ultrascaled n- and p-type Si nanowire field-effect transistors (NW FETs) with [100], [110], and [111] as channel orientations are simulated in the presence of electron-phonon scattering using an atomistic quantum transport solver based on the sp3d5s∗ tight-binding model for electrons and holes, a modified Keating model for phonons, and the nonequilibrium Green’s function formalism. The channel resistances of devices with different gate lengths and carrier concentrations are computed at room temperature and used to extract phonon-limited, ballistic, and effective low-field mobilities. It is found that a [110] channel represents the best choice for high n- and p-type NW FET performances.
Mythmanagement: An Examination of Corporate Diversification As Fact and Theory

The article reviews the book “Myth Management: An Examination of Corporate Diversification As Fact and Theory,” by Milton Leontiades.
Associations Between Physical Activity and Reduced Rates of Hopelessness, Depression, and Suicidal Behavior Among College Students

Objective: The authors explored associations among types of physical activity and hopelessness, depression, and suicidal behavior among college students. Participants: Participants included 43,499 college students aged 18 to 25 who completed the 2005 National College Health Assessment conducted by the American College Health Association. Methods: The authors used logistic regression modeling to compare the odds of experiencing hopelessness, depression, and suicidal behavior in students who engaged in various levels of aerobic and strength or toning activity with students who did not perform these activities. Results: Men and women who engaged in some physical activity each week demonstrated a reduced risk of hopelessness, depression, and suicidal behavior compared with their inactive counterparts. Conclusions: This study provides empirical evidence that establishes the association between physical activity, especially aerobic activity, and reduced risk of hopelessness, depression, and suicidal behavior am...
The Distribution of Energy in Molecules.

The author has recently attempted to account for the rates of unimolecular reactions by a theory [1] which assumes activation by collision and treats the reacting molecules as mechanical systems with many internal degrees of freedom. A somewhat similar theory had been advanced earlier by Rice and Ramsperger [2]. For the complete development of the author's theory it is necessary to solve the problem: Given a number of oscillators, classical or quantum, harmonic or otherwise, and a value for the total energy of these oscillators, calculate the chance that a specified one of the oscillators shall have energy in excess of some given value. The solution of this problem for the case of classical harmonic oscillators was given in the author's first paper. The methods used there, however, were somewhat elementary and not suitable for more complex cases. The problem may be solved, in general, by a consideration of the total phase-space volumes associated with various conditions of the molecule. Some of the special cases have been worked out, and will be considered here.
Haemoglobin P (the Galveston type).

AN earlier communication1 described a new variant of human haemoglobin tentatively called the ‘Galveston type’. This variant appears identical with haemoglobin L2 in paper electrophoresis, veronal buffer, pH 8.6, 0.05 M, but differs from similar types in that it does not separate from haemoglobin A in free electrophoresis, cacodylate buffer, pH 6.2–6.9, 0.1 M. It is now suggested that this variant (found in a Negro woman, ‘MTu’, and in one of her two children) be called haemoglobin P. Fig. 1 shows a photograph of the paper electrophoresis pattern of ‘MTu's’ haemoglobin sample, compared with those from subjects with sickle cell trait, haemoglobin G trait, and haemoglobin Q trait. (The sample of haemoglobin G trait3 is from the subject ‘AK’; that of haemoglobin Q trait4 was kindly supplied by Dr. H. Lehmann.) The various types of haemoglobin in these samples, listed in order of decreasing mobility, are as follows: A, Q, G, P and S.
Efficacy of Azathioprine Versus Cyclosporine on Kidney Graft Survival in Transfused and Nontransfused Ummatched Mongrel Dogs

Sixteen mongrel dogs had bilateral nephrectomy and received a renal allograft from an unmatched mongrel. One group of eight dogs was treated orally with azathioprine and prednisone; another group of eight dogs was treated orally with cyclosporine and prednisone. Four dogs of each group received four blood transfusions each prior to surgery. Mean survival time was nearly the same in the azathioprine-treated and the cyclosporine-treated dogs. Transfusions prolonged survival in the azathioprine-treated group but not in the cyclosporine-treated group. Retrospective measurement of whole blood trough cyclosporine concentrations indicated marked variation between dogs and in the same dog at different times. This variation may have influenced graft survival. Only one dog survived the 9-month period of observation, indicating that refinements of the techniques used in this study will be required for long-term survival of renal allografts in unrelated mongrel dogs.
Die darstellungen der starken kopplung und das resonanzproblem der meson-nucleon-streuung

Abstract This paper deals with the completion of the strong-coupling method in meson field theory. By means of a canonical and non-linear transformation of variables the original meson field is split into a free meson part and a self field part of the nucleon. The transformation is defined so that the interaction between the compound nucleon system thus arising and the free mesons vanishes in the case of infinitely strong coupling. It is shown that there exists a family of transformations satisfying the conditions. A system of equations for certain transformation functions is stated as the consequence of the conditions. The solutions of the field-splitting problem are investigated. The general scheme for a strong-coupling approximation method based on this field splitting is derived, and the problem of calculating the pion-nucleon resonance scattering from the strong coupling theory is treated on this basis. A special approximation is made for calculations near the resonance. Numerical results obtained from such a calculation are discussed. For the sake of simplicity the symmetric scalar fixed-source meson theory is used. But the principle of the method will be the same in the more essential but more complicated symmetric pseudoscalar case. Thus the present considerations will serve to guide an analogous investigation using the symmetric pseudoscalar theory.
Pyridoxal‐5′‐phosphate as a probe for rotational diffusion

Abstract Pyridoxal-5′-phosphate, a metabolic derivative of vitamin B6, was successfully used as a probe for rotational diffusion. As the intrinsic cofactor in glycogen phosphorylase b , in binding with bovine serum albumin and in mixed micelles, the Schiff base adduct exhibited transient absorption dichroism at μs times. Its usefulness in measuring the slow rotation of proteins and micelles was demonstrated.
The Modeling and Simulation of the Precision CNC Lathe Knife Tower Servo System Based on Matlab/Simulink

Based on the analysis of the PMSM’s mathematic model, we’ll use the Matlab/Simulink to construct the simulation model of the precision CNC lathe knife tower servo system. The control system uses the classical three closed structure. According to the servo system's performance requirements, we'll do the parameter selection and simulation. The simulation result proves the validity of the model and provides the theory basis for the system's design and debug.
CYTOLOGICAL EVIDENCE OF SECRETORY ACTIVITY IN THE MAMMALIAN PARATHYROID GLAND

ALTHOUGH there is abundant clinical and experimental evidence of hormone production by the parathyroid gland, clear cytological evidence of secretory - activity has not been forthcoming. Study of the human gland has demonstrated the presence of fatty inclusions, glycogen and occasionally pigment in the ‘principal’ cells, to which the essential role in hormone production is generally ascribed; in addition to these inclusions, no recognizable secretion antecedents have been observed. The ‘oxyphile’ cells are usually regarded as a degenerative form of the ‘principal’ cells; they are typically filled with acidophilic granules,which are com monly considered to be of no importance in the secretion of the gland. A large nunv ber of mammals has been investigated; the parathyroid usually consists of a single basic cell type,homologous with the ‘principal’ cell of man; ‘oxyphile’ cells are absent in the common laboratory mammals, but have been described in the cow and steer.
Superimposed Training for Channel Shortening Equalization in OFDM

In orthogonal frequency division multiplexing (OFDM) systems, the cyclic prefix (CP) is required to be greater than the length of the channel impulse response to avoid inter-block interference. However, a long CP decreases power and bandwidth efficiences. Recently channel shortening equalizers (CSEs) have been introduced to enable the use of a shorter CP, but they either require perfect channel knowledge, or demand high complexity and long decoding delay when the channel is unknown. In this paper, we propose a low complexity CSE for OFDM with unknown channels by using superimposed training. Our unique design achieves bandwidth efficient channel estimation, and low complexity channel shortening equalization as well as symbol decoding. Simulation results demonstrate the effectiveness of the proposed scheme.
Amiodarone Analysis by Capillary Electrophoresis

Abstract Amiodarone is a broad spectrum antiarrhythmic medication. Toxicity symptoms can occur at high serum levels of this drug; thus the level of this drug requires routine monitoring. Because this drug is very hydrophobic, it is difficult to analyze by both HPLC and capillary electrophoresis (CE). A simple method for measuring amiodarone (A) by CE without sample extraction is described. It is based on separation of the drug in a strong phosphate buffer 170 mmol/L, pH 5.9, with added ethanol, and stacking after acetonitrile deproteinization. The ethanol in the phosphate buffer aids to solubilize the drug, migrate it from the neutral to the cationic molecules region, and to separate it from its metabolite, desethylamiodarone (D). The metabolite D is pharmacologically active; has the similar therapeutic range as the parent drug; similar ultra violet absorption; and at steady state is present at equal ratio. Based on these facts, we choose for routine analysis, conditions where the drug and its metabolite ...
An XRD and TEM Investigation of the Structure of Alumina-Supported Ceria–Zirconia

Abstract Dispersed CeO 2 –ZrO 2 is of interest as a thermally stable oxygen-storage component of automotive catalysts. Alumina-supported CeO 2 –ZrO 2 samples were prepared by coimpregnation in order to maximize the interaction between Zr and Ce. The phases present, their particle sizes and the interactions among the phases of fresh, steam-aged and reduced samples were investigated by XRD and TEM. In the fresh samples, a particulate solid solution phase Zr x Ce 1− x O 2 of cubic symmetry was identified. However, the zirconium concentration of this particulate phase was found to be smaller than that expected from the Zr loading. This suggests the existence of finely dispersed zirconia on the Al 2 O 3 surface. For the steam-aged samples, a second Ce–Zr oxide solid solution phase of higher Zr concentration and tetragonal symmetry was found in addition to the original CeO 2 -based cubic solid solution. The appearance of this second phase may have resulted from sintering of the highly dispersed zirconia. The highly dispersed zirconia may also be responsible for preventing reaction between CeO 2 and the Al 2 O 3 support, since CeAlO 3 was found only in high-temperature reduced samples without zirconia. The particle sizes of the various phases were measured by XRD and TEM. The particle size of the supported particulate phase decreased with increasing zirconium loading, but a discrepancy was noted between the XRD and the TEM results. This discrepancy is discussed in terms of compositional inhomogeneity in the Zr x Ce 1− x O 2 solid solution phase.
Selected complementary feeding practices and their association with maternal education.

OBJECTIVE. As infants transition from a milk-based diet to one that includes most food groups, the timing of the transition, how infants are fed, and the quality of their diet can have important health implications. Our objective is to describe these factors for US infants. METHODS. We analyzed data from the Infant Feeding Practices Study II. Sample sizes varied for relevant questions from ∼1600 to ∼2400. We analyzed the prevalence of 14 feeding practices and their association with the mothers9 education and also examined participants9 use of commercial baby foods. RESULTS. Approximately 21% of the mothers introduced solid foods before 4 months; 7% introduced solids after 6 months. Twenty-nine percent of the mothers introduced >3 new foods per week to infants aged 5 to 10 months. Approximately 20% of the mothers fed juice before 6 months, fed cow9s milk before 12 months, and fed infants CONCLUSIONS. Nutrition and feeding guidance should be especially targeted to mothers with a high school education or less.
Immunology and biochemistry of the regan isoenzyme

The Regan isoenzyme is a placental-type alkaline phosphatase that is expressed in a number of human tumors, particularly in gonadal and urologic cancers. Attention is given to the unique gene that codes for placental alkaline phosphatase and the similarities and differences in the tumor and placental gene products. The separation and identification of individual organ-specific isoenzymes is accomplished by a variety of biochemical, immunologic, and electrophoretic techniques and the correlation of the Regan isoenzyme, non-Regan isoenzyme, and Nagao isoenzyme, and the Kasahara isoenzyme is made with their developmental counterparts. The L-leucine-sensitivity phenotypes of placental and tumor alkaline phosphatases and the non-Regan early placental type alkaline phosphatases appear to be developmental phase-specific. Oncotrophoblast gene expression has been investigated with monophenotypic cell culture lines as a consequence of modulation by prednisolone and hyperosmolarity. Finally, general discussion of oncodevelopmental proteins as tumor markers precedes a current opinion of Regan isoenzyme as a tumor marker. Evidence now points to seminoma as a consistent producer of Regan isoenzyme although much more work will be required to establish its clinical utility.
Bernstein's asymptotic best bound for the Kth derivative of a polynomial

A complete proof, which yields an error term showing a dependence on n and x, is given for Bernstein's result that the best bound on the kth derivative on polynomials of degree less than or equal to n, at a point x in ( −1, 1), is asymptotic to (n√1 − x2)k as n tends to infinity.