bluuebunny/crossref_metadata_2025 huggingface dataset:
Trends in Overweight and Obesity in Chinese Adults: Between 1991 and 1999–2000
Authors: Wildman Rachel P. , Gu Dongfeng , Muntner Paul , Wu Xiqui , Reynolds Kristi , Duan Xiufang , Chen Chung‐Shiuan , Huang Guangyong , Bazzano Lydia A. , He Jiang
Published: April 2008

Objective: The aim of this study was to evaluate trends in BMI and the prevalence of overweight (BMI ≥ 25 kg/m2) and obesity (BMI ≥ 30 kg/m2) between 1991 and 1999–2000 among Chinese adults.

Methods and Procedures: In this study, two population‐based samples of Chinese adults aged between 45 and 79 years (n = 7,858 during each period), and comparable in the distributions of age, gender, degree of urbanization, and region (North/South) were used. Height and weight were measured using identical procedures at each period, and BMI was calculated as weight (in kilogram) divided by height (in square meter).

Results: From 1991 to 1999–2000, the mean BMI increased from 21.8 to 23.4 kg/m2 among men and from 21.8 to 23.5 kg/m2 among women (each P < 0.001). Among men, the prevalence of overweight and obesity increased from 9.6 and 0.6%, respectively, in 1991 to 20.0 and 3.0%, respectively, in 1999–2000 (each P < 0.001). Among women, the prevalence of overweight and obesity increased from 14.5 and 1.8%, respectively, in 1991 to 26.5 and 5.2%, respectively, in 1999–2000 (each P < 0.001). The prevalence of overweight and obesity increased in all age groups, in rural and urban areas, and in North and South China, with greater relative increases in obesity among older age groups, South China, and rural areas (P interaction < 0.05).

Discussion: Overweight and obesity increased tremendously during the 1990s in China. These data underscore the need for national programs in weight maintenance and reduction, to prevent obesity‐related outcomes in China.
Elevated Soluble Lectin‐like Oxidized LDL Receptor‐1 (sLOX‐1) Levels in Obese Postmenopausal Women
Authors: Brinkley Tina E. , Kume Noriaki , Mitsuoka Hirokazu , Phares Dana A. , Hagberg James M.
Published: April 2008

We investigated the association between soluble lectin‐like oxidized low‐density lipoprotein receptor‐1 (sLOX‐1) levels and obesity in older women. Fifty‐one postmenopausal women (10 lean, 22 overweight, and 19 obese) were included in this small retrospective analysis. Plasma sLOX‐1 levels were measured using a chemiluminescent enzyme‐linked immunoassay. Plasma levels of sLOX‐1 were significantly higher in obese women (55.33 ± 4.49 pg/ml) compared to lean (30.91 ± 6.19 pg/ml, P = 0.002) and overweight women (38.31 ± 4.18 pg/ml, P = 0.017). Plasma sLOX‐1 levels were positively associated with body weight, BMI, total body fat, and trunk fat. The relationship between sLOX‐1 and BMI was attenuated after adjustment for age, hormone replacement therapy, and body fat. In conclusion, obese women have higher sLOX‐1 levels, which may reflect increased LOX‐1 expression in adipose tissue.
Association Between BMI and Metabolic Syndrome and Adenomatous Colonic Polyps in Korean Men
Authors: Lee Go‐Eun , Park Hye S. , Yun Kyung E. , Jun Sung H. , Kim Hong K. , Cho Sung‐il , Kim Jin H.
Published: April 2008

Obesity and insulin resistance are associated with the risk of colon cancer. Adenomatous colonic polyps are precancerous lesions of colon cancer. We investigated whether BMI and the metabolic syndrome are associated with the presence of adenomatous colonic polyps in Korean men. Anthropometric measurements, metabolic risk factors, and colonoscopic pathologic findings were assessed in 1,898 men who underwent routine colonoscopy at the Health Promotion Center of Asan Medical Center in 2005. The modified National Cholesterol Education Program Adult Treatment Panel III (NCEP‐ATP III) and International Diabetes Federation (IDF) criteria were used for the definition of the metabolic syndrome. Multiple logistic regression analysis was used to evaluate the association between BMI and the metabolic syndrome and adenomatous polyps. Compared with men in the 1st quintile of the BMI, the adjusted odds ratio (OR) and 95% confidence interval (CI) for adenomatous polyps in men in the 2nd, 3rd, 4th, and 5th quintiles of the BMI were 1.55 (1.10–2.19), 1.57 (1.10–2.24), 1.94 (1.34–2.81), and 1.99 (1.31–3.01), respectively (P for trend <0.0001). Men with triglycerides (TGs) ≥150 mg/dl were significantly more likely to have adenomatous polyps than were men with TG <150 mg/dl (OR 1.29; 95% CI 1.03–1.62). As a function of the number of metabolic risk factors, the ORs for adenomatous polyps were 1.41 (1.03–1.93), 1.52 (1.08–2.12), 1.46 (1.01–2.12), and 1.77 (1.08–2.90) for 1, 2, 3, and ≥4 risk factors, respectively (P for trend <0.05). Adenomatous colonic polyps were significantly associated with increased BMI levels. Subjects with even one component of the metabolic syndrome had a significantly higher risk for developing adenomatous polyps compared to those subjects without any component in Korean men.
Mechanism by Which BMI Influences Leisure‐time Physical Activity Behavior
Authors: Godin Gaston , Bélanger‐Gravel Ariane , Nolin Bertrand
Published: April 2008

Objective: The objective of this prospective study was to clarify the mechanism by which BMI influences leisure‐time physical activity. This was achieved in accordance with the assumptions underlying the Theory of Planned Behavior (TPB), considered as one of the most useful theories to predict behavior adoption.

Methods and Procedures: At baseline, a sample of 1,530 respondents completed a short questionnaire to measure intention and perceived behavioral control (PBC), the two proximal determinants of behavior of TPB. Past behavior, sociodemographic variables, and weight and height were also assessed. The dependent variable, leisure‐time physical activity was assessed 3 months later.

Results: Hierarchical multiple regression analyses revealed that BMI is a direct predictor of future leisure‐time physical activity, not mediated by the variables of TPB. Additional hierarchical analyses indicated that BMI was not a moderator of the intention‐behavior and PBC‐behavior relationships.

Discussion: The results of this study suggest that high BMI is a significant negative determinant of leisure‐time physical activity. This observation reinforces the importance of preventing weight gain as a health promotion strategy for avoiding a sedentary lifestyle.
Prevalence and Characteristics of Energy Underreporting in African‐American Girls
Authors: Lanctot Jennifer Q. , Klesges Robert C. , Stockton Michelle B. , Klesges Lisa M.
Published: April 2008

Objective: To determine the frequency and characteristics of energy intake underreporting in African‐American preadolescent girls as part of the Girls health Enrichment Multi‐site Studies (GEMS).

Methods and Procedures: Energy intake was summarized using the Nutrition Data System for Research software and computed as a 3‐day average of 24‐h dietary recalls. Physical activity was assessed by an accelerometer, basal metabolic rate (BMR) was estimated using the World Health Organization's prediction equation, and underreporting of caloric intake was based on the Goldberg equation.

Results: Using a conservative criterion for determining energy underreporting, we classified 54.8% of the girls as underreporters; 45.2% were classified as plausible reporters. Factors related to underreporting included higher BMI (β = −0.506, P ≤ 0.001), older age (β = −0.159, P = 0.001), greater unhealthy eating behaviors (β = −0.118, P = 0.025), and higher self‐efficacy for diet (β = −0.098, P = 0.033).

Discussion: Underreporting of dietary intake, specifically energy, is common in African‐American preadolescent girls and can be partially explained by weight status and psychosocial variables. The extent of dietary underreporting in specific and high‐risk populations is largely unknown and could be evaluated by routinely including a report of such an index in future research studies.
Interaction Between PPARγ2 Variants and Gender on the Modulation of Body Weight
Authors: Morini Eleonora , Tassi Vittorio , Capponi Daria , Ludovico Ornella , Dallapiccola Bruno , Trischitta Vincenzo , Prudente Sabrina
Published: April 2008

Conflicting results have been reported regarding the effect of the peroxisome proliferator‐activated receptor‐γ−2 (PPARγ2) Pro12Ala polymorphism, (singly or in combination with the silent C1431T polymorphism) on BMI. Gender‐based dimorphism has been evidenced for genes that affect BMI, but few and conflicting data are available regarding PPARγ2. We sought to investigate whether the Pro12Ala interacts with gender in modulating BMI in 566 nondiabetic unrelated white subjects (men:women = 211:355, age 36.59 ± 11.85; BMI 25.36 ± 4.53). In the whole study population, BMI, fasting glucose and insulin levels, and lipid profile were similar in Ala12 carriers (i.e., XA) and Pro/Pro homozygous subjects. Among the men, but not among the women, X/Ala individuals showed higher BMI (25.9 ± 3.6 vs. 28.2 ± 4.9, P = 0.006) and risk of obesity (odds ratio = 2.85, 95% confidence interval = 1.07–7.62). A significant gene‐gender interaction in modulating BMI was observed (P = 0.039). Among the men, but not among the women, those carrying Ala‐T haplotype (i.e., containing both Ala12 and T1431 variants) showed the highest BMI (haplo‐score = 3.72, P = 0.0014). Our data indicate that in whites from Italy the PPARγ2 Pro12Ala polymorphism interacts with gender in modulating BMI, thereby replicating some, but not all, earlier data obtained in different populations. Whether the PPARγ2‐gender interaction is a general phenomenon across different populations, is still an open question, the answer to which requires additional, specifically designed, studies.
Insulin Increases Tristetraprolin and Decreases VEGF Gene Expression in Mouse 3T3–L1 Adipocytes
Authors: Cao Heping , Urban Joseph F. , Anderson Richard A.
Published: April 2008

Objectives: Tristetraprolin (TTP) family proteins (TTP/ZFP36; ZFP36L1, ZFP36L2, ZFP36L3) destabilize adenylate uridylate‐rich element‐containing mRNAs encoding cytokines, such as tumor necrosis factor (TNF) and vascular endothelial growth factor (VEGF). Little is known about the expression and insulin regulation of TTP and related genes in adipocytes. We analyzed the relative abundance of TTP family mRNAs in 3T3‐L1 adipocytes compared to RAW264.7 macrophages and investigated insulin effects on the expression of 43 genes in 3T3‐L1 adipocytes.

Methods and Procedures: Insulin was added to mouse 3T3‐L1 adipocytes. Relative abundance of mRNA levels was determined by quantitative real‐time PCR. TTP and ZFP36L1 proteins were detected by immunoblotting.

Results: Zfp36l1 and Zfp36l2 genes were expressed at eight‐ to tenfold higher than Ttp in adipocytes. Zfp36l3 mRNA was detected at ∼1% of Ttp mRNA levels in adipocytes and its low level expression was confirmed in RAW cells. Insulin at 10 and 100 nmol/l increased Ttp mRNA levels by five‐ to sevenfold, but decreased those of Zfp36l3 by 40% in adipocytes after a 30‐min treatment. Immunoblotting showed that insulin induced TTP but did not affect ZFP36L1 protein levels in adipocytes. Insulin decreased mRNA levels of Vegf and a number of other genes in adipocytes.

Discussion: Insulin induced Ttp mRNA and protein expression and decreased Vegf mRNA levels in adipocytes. Zfp36l3 mRNA was detected, for the first time, in cells other than mouse placenta and extraembryonic tissues. This study established a basis for the investigation of TTP and VEGF genes in the regulation of obesity and suggested that Vegf mRNA may be a target of TTP in fat cells.
Functionalization of FeCo alloy nanoparticles with highly dielectric amorphous oxide coatings
Authors: Nguyen Q. , Chinnasamy C. N. , Yoon S. D. , Sivasubramanian S. , Sakai T. , Baraskar A. , Mukerjee S. , Vittoria C. , Harris V. G.
Published: April 2008

FeCo alloy nanoparticles have been prepared by using a two step modified polyol process using Fe(II) chloride and Co acetate tetrahydrate as Fe and Co metal precursors. Tetraethyl silicate, aluminum isopropoxide, and zirconium(IV) acetyl acetonate were used to make amorphous SiO2, Al2O3, and ZrO2 coatings, respectively. X-ray diffraction studies showed that there are no crystalline peaks corresponding to SiO2, Al2O3, and ZrO2 because the oxide coatings of the FeCo core are amorphous in nature. The scanning electron micrograph analysis depicted the cubic nature of the particles with mean particle size of about 45nm. The maximum saturation magnetization of 205emu∕g was achieved at 300 and 4K. FeCo nanocomposites were screen printed as films and aligned by using an external magnetic field of 10kOe. The microwave properties measured by in-plane ferromagnetic resonance at various frequencies indicate a minimum linewidth of ≈3700Oe.
Design of adaptive compensator of force imbalance for a single active magnetic bearings suspended rotor system
Authors: Fan Yi-Hua , Chen Kuan-Yu , Weng Duan-Liang , Lee Ying-Tsun
Published: April 2008

This study proposes a model-based force estimator with an adaptive tuner for a single active magnetic bearing suspended rotor system to eliminate the vibration associated with imbalance of mass. The adaptive tuner is added to the integral-typed observer to overcome the estimation error caused by the parameter uncertainty and the model uncertainty. Simulation results show that the adaptive estimation system is more accurate than the integral-type estimator, even though the system model has a 20% parameter error, and the feed-forward compensator can ameliorate the rotational accuracy in the operational range.
Dissipation of classical energy in nonlinear quantum systems
Authors: Pereverzev Andrey , Pereverzev Yuriy V. , Prezhdo Oleg V.
Published: April 2008

We show using two simple nonlinear quantum systems that the infinite set of quantum dynamical variables, as introduced in quantized Hamilton dynamics [O. V. Prezhdo and Y. V. Pereverzev, J. Chem. Phys. 113, 6557 (2000)], behave as a thermostat with respect to the finite number of classical variables. The coherent classical component of the evolution decays by coupling to the chaotic quantum reservoir. The classical energy, understood as the part of system energy expressible through the average values of coordinates and momenta, is transferred to the quantum energy expressible through the higher moments of coordinates and momenta and other quantum variables. At long times, the classical variables reach equilibrium, and the classical energy fluctuates around the equilibrium value. These phenomena are illustrated with the exactly solvable Jaynes–Cummings model and a nonlinear oscillator.
Effect of N2, Ar, and O2 plasma treatments on surface properties of metals
Authors: Kim Soo Young , Hong Kihyon , Kim Kisoo , Yu Hak Ki , Kim Woong-Kwon , Lee Jong-Lam
Published: April 2008

We report the effect of N2, Ar, and O2 plasma treatments on the surface properties of metals. The carbon atoms reduced more in O2 and Ar plasma than in N2 plasma due to a chemical reaction with O2 plasma and large plasma density in Ar plasma. A water contact angle decreased after the plasma treatment regardless of the kinds of plasma gas, showing the increase in the hydrophilicity in surfaces. Synchrotron radiation photoemission spectroscopy data showed that the work function increased after N2, Ar, and O2 plasma treatments in sequence. This is due to the reduction of carbon atoms and the formation of O-rich surface in O2 plasma case.
Dissociative recombination of OPCl+ and OPCl2+: Pushing the upper mass limit at CRYRING
Authors: Zhaunerchyk V. , Thomas R. D. , Geppert W. D. , Hamberg M. , Kamińska M. , Vigren E. , Larsson M. , Midey A. J. , Viggiano A. A.
Published: April 2008

The dissociative recombination of OPCl+ and OPCl2+ has been studied at the storage ring CRYRING. The rate constants as a function of electron temperature have been derived to be 7.63×10−7(Te∕300)−0.89 and >1.2×10−6(Te∕300)−1.22cm3s−1, respectively. The lower limit quoted for the latter rate constant reflects the experimental inability to detect all of the reaction products. The branching fractions from the reaction have been measured for OPCl+ at ≈0eV interaction energy and are determined to be N(O+P+Cl)=(16±7)%, N(O+PCl)=(16±3)% and N(OP+Cl)=(68±5)%. These values have been obtained assuming that the rearrangement channel forming P+ClO is negligible, and ab initio calculations using GAUSSIAN03 are presented for the ion structures and energetics to support such an assumption. Finally, the limitations to using heavy ion storage rings such as CRYRING for studies into the dissociative recombination of large singly charged molecular ions are discussed.
Evolution of the vibrational spectrum of ammonia from single molecule to bulk
Authors: Slipchenko Mikhail N. , Sartakov Boris G. , Vilesov Andrey F.
Published: April 2008

Ammonia clusters (NH3)n (n=2–104) have been assembled inside helium droplets and studied via infrared laser spectroscopy. The studied spectral range of 3100–3500cm−1 covers the ν1 and ν3 fundamental stretching bands as well as the 2ν4 overtone of the bend of ammonia molecules. The results show strong coupling of the 2ν4 overtone with the fundamental vibrations for all cluster sizes except dimers. The intensity of the ν3 band relative to the total intensity in the spectrum increases from about 30% to about 80% upon increase of the average cluster size from ⟨n⟩=5 to ⟨n⟩=104. We attributed this effect to the concomitant decrease in the fraction of the surface molecules. The results indicate that ammonia clusters obtained in He droplets have a compact structure and that inner molecules in the clusters have similar hydrogen-bonded coordination as in the crystalline form of ammonia. This surprising result is ascribed to a directionality of the hydrogen bond, which guides the low temperature growth of the cluster in He droplets.
Kinetic study of the “surface explosion” phenomenon in the NO+CO reaction on Pt(100) through dynamic Monte Carlo simulation
Authors: Alas S. J. , Vicente L.
Published: April 2008

The extremely narrow production peak of N2 and CO2 which occurs in the reaction of NO+CO on Pt(100), a phenomenon known as “surface explosion,” is studied using a dynamic Monte Carlo method on a square lattice at low pressure under isothermal conditions. This analysis incorporates recent experimental evidence obtained for the same reaction on a Rh(111) surface, which has shown that N2 production occurs either from the classical N+N recombination step or by the formation and successive decay of a (N–NO)* intermediary species. Moreover, the NO dissociation rate is inhibited by coadsorbed NO and CO molecules and is enhanced both by the presence of empty sites and adsorbed N atoms as nearest neighbors. These effects are taken into account in this study, along with the experimental adsorption, desorption, and diffusion rates of the reactants. The “explosive” phenomenon is analyzed through the evolution over time of an adsorbed NO+CO monolayer at a fixed temperature of 400K. Furthermore, as the diffusion processes of the adsorbates are included, cellular structures are observed. Our simulations show quantitative agreement in the position of maxima with those obtained through experiments using isothermal desorption mass spectroscopy.
Projected gradient algorithms for Hartree-Fock and density matrix functional theory calculations
Authors: Cancès Eric , Pernal Katarzyna
Published: April 2008

We present projected gradient algorithms designed for optimizing various functionals defined on the set of N-representable one-electron reduced density matrices. We show that projected gradient algorithms are efficient in minimizing the Hartree-Fock or the Müller-Buijse-Baerends functional. On the other hand, they converge very slowly when applied to the recently proposed BBk (k=1,2,3) functionals [O. Gritsenko et al., J. Chem. Phys. 122, 204102 (2005)]. This is due to the fact that the BBk functionals are not proper functionals of the density matrix.
Hydrogenation of CO on a silica surface: An embedded cluster approach
Authors: Goumans T. P. M. , Catlow C. Richard A. , Brown Wendy A.
Published: April 2008

The sequential addition of H atoms to CO adsorbed on a siliceous edingtonite surface is studied with an embedded cluster approach, using density functional theory for the quantum mechanical (QM) cluster and a molecular force field for the molecular mechanical (MM) cluster. With this setup, calculated QM/MM adsorption energies are in agreement with previous calculations employing periodic boundary conditions. The catalytic effect of the siliceous edingtonite (100) surface on CO hydrogenation is assessed because of its relevance to astrochemistry. While adsorption of CO on a silanol group on the hydroxylated surface did not reduce the activation energy for the reaction with a H atom, a negatively charged defect on the surface is found to reduce the gas phase barriers for the hydrogenation of both CO and H2CO. The embedded cluster approach is shown to be a useful and flexible tool for studying reactions on (semi-)ionic surfaces and specific defects thereon. The methodology presented here could easily be applied to study reactions on silica surfaces that are of relevance to other scientific areas, such as biotoxicity of silica dust and geochemistry.
Plane model of fluid interface rupture in an electric field
Authors: Gubarenko Sergey I. , Chiarot Paul , Ben Mrad Ridha , Sullivan Pierre E.
Published: April 2008

Modeling of an air-fluid interface in an electric field is presented. Specifically, equilibrium of the interface under the dominant forces—electric stress, surface tension, and pressure—is investigated. Since interface shape and equilibrium are related, the shape of an electrified interface is also addressed. To determine the electric stress, an analytical expression for the electric field in the vicinity of the interface is determined. The operating point of the interface is shown to exist in a three-dimensional parameter space that is divided by a critical surface into equilibrium, quasiequilibrium, and nonequilibrium subdomains. The three parameters are applied voltage, electrode separation, and pressure difference. Interface size, counterelectrode size, and fluid properties are also considered. The subdomain in which the operating point resides defines the important characteristics of the interface. The operating point moves within, and transfers between, equilibrium subdomains, and points on the critical surface represent “rupture points” of the interface. The final shape of the interface is solved iteratively using this equilibrium model. Interfaces emitting an electrospray can have a range of apex angles, and it is shown that the magnitude of this angle impacts equilibrium. It is revealed that the excess pressure difference term is critical in determining the interface shape (specifically the cone generatrix) and that minimization of the potential energy of all forces can be used to predict the magnitude of the apex angle and pressure immediately after interface rupture. The equilibrium model is important from an operational and optimization perspective, as it is useful to predict the conditions required to break equilibrium and transfer to a quasiequilibrium state (i.e., an electrospray), and the conditions necessary to maintain quasiequilibrium once it is formed.
Nonholonomic Ricci flows. II. Evolution equations and dynamics
Authors: Vacaru Sergiu I.
Published: April 2008

This is the second paper in a series of works devoted to nonholonomic Ricci flows. By imposing nonintegrable (nonholonomic) constraints on the Ricci flows of Riemannian metrics, we can model mutual transforms of generalized Finsler–Lagrange and Riemann geometries. We verify some assertions made in the first partner paper and develop a formal scheme in which the geometric constructions with Ricci flow evolution are elaborated for canonical nonlinear and linear connection structures. This scheme is applied to a study of Hamilton’s Ricci flows on nonholonomic manifolds and related Einstein spaces and Ricci solitons. The nonholonomic evolution equations are derived from Perelman’s functionals which are redefined in such a form that can be adapted to the nonlinear connection structure. Next, the statistical analogy for nonholonomic Ricci flows is formulated and the corresponding thermodynamical expressions are found for compact configurations. Finally, we analyze two physical applications, the nonholonomic Ricci flows associated with evolution models for solitonic pp-wave solutions of Einstein equations, and compute the Perelman’s entropy for regular Lagrange and analogous gravitational systems.
Role of defects in the nonmonotonic behavior of secondary relaxation of polypropylene glycols
Authors: Grzybowska K. , Grzybowski A. , Paluch M.
Published: April 2008

A nonmonotonic relaxation kinetic model [Ya. Ryabov et al., J. Phys. Chem. B 105, 1845 (2001)] is successfully applied to describe an intriguing slow down in the dielectric secondary γ relaxation of polypropylene glycols (PPGs) with increasing temperature near the glass transition. The anomalous behavior is interpreted as a result of two simultaneous events: A thermal activation and a defect formation in the hydrogen bonded network formed by molecules of PPGs. This new insight into the molecular mechanism, which is responsible for the suggested sensitivity of the secondary process in PPGs to the glass transition phenomenon, is compared to our previous results obtained in terms of the minimal model for secondary relaxations.
A new advanced experimental setup for in-depth study of the interfacial reaction during reactive wetting
Authors: Frenznick Sascha , Stratmann Martin , Rohwerder Michael
Published: April 2008

Reactive wetting plays a crucial role in many technical processes, from soldering in microelectronics, production of metal/ceramic composites, to hot dip galvanizing in mass production of zinc coated steel sheet. In all these cases the wetting behavior of metal melts on different surfaces plays a crucial role in material joining and coating. In all these processes the formation of the interfacial reaction layer has to occur within as short a time as possible in order to ensure a fast overall production speed. As the interfacial layer determines the stability of the formed composites, detailed knowledge of its growth mechanisms is required for a directed process optimization. However, the investigation of the processes occurring at the buried interface between substrate and wetting phase is difficult, especially for the case of liquid metal wetting metallic or ceramic solid substrates at high temperatures. Here, a novel advanced technique for the investigation of high temperature wetting processes up to a temperature of 1100K is presented. It is based on the sessile drop technique but, in addition, allows spinning off the droplet at any chosen wetting time, thus providing direct access to the interfacial reaction layer. Since the experimental setup is integrated into a UHV compatible reaction chamber, not only excellent control of the composition of the atmosphere is ensured, but also direct transfer to surface analytical tools such as scanning electron microscope or electron spectroscopy for chemical analysis without intermediate exposure to air is realized. As will be shown for the case of hot dip galvanising of steel, this is an outstanding advance compared to existing methods.
Landau levels and magneto-optical properties of graphene ribbons
Authors: Huang Y. C. , Lin M. F. , Chang C. P.
Published: April 2008

On the basis of Peierl coupling tight-binding model, we study the low energy magnetoelectronic properties of zigzag graphene ribbons by changing the ribbon width from the nanometer to the mesoscopic scale. The evolution of the Landau levels with the ribbon width shows that the number and the range of Landau levels are chiefly dominated by the ribbon width and the magnetic field (B). The Landau-level energies abide by the simple relation ∣E∣∝∣n∣B at low energy, not at the high energy (n subband index). However, a scaling law between the number of Landau levels and the ribbon width cannot be figured out. The Landau states occur only when the ribbon width is close to or greater than the distribution width of the Landau wave function and more Landau levels are generated with the increase in width. The low-frequency magnetoabsorption spectra reveal electronic properties and, thus, exhibit distinguishable delta-function-like peaks (Landau peaks). The peak height runs higher when the width increases, for more Landau states are allowed in a wider ribbon. The spectral frequencies of the Landau peaks are not determined by the ribbon width but by the field strength. The transition channels of the Landau peaks are identified and the selection rule is analyzed and discussed. The bearded defects can hardly affect the magnetoabsorption peaks due to the Landau levels.
Differentiating the contributions between localized surface plasmon and surface plasmon polariton on a one-dimensional metal grating in coupling with a light emitter
Authors: Chuang Wen-Hung , Wang Jyh-Yang , Yang C. C. , Kiang Yean-Woei
Published: April 2008

The authors demonstrate the differentiation between the contributions of localized surface plasmon (LSP) and surface plasmon polariton (SPP) couplings with an emitting dipole to emission enhancement in a metallic grating structure. Because of the relatively higher loss and in-plane radiation of the SPP modes, the LSP modes dominate the enhancement effect. However, because the LSP resonance energy is sensitive to the metal/dielectric interface geometry, it may be difficult to precisely implement a particular geometry and achieve the emission enhancement of a desired emission wavelength based on the LSP coupling. On the other hand, because the SPP feature can be controlled by the period of a grating structure, the implementation of the SPP coupling for emission enhancement in a practical device can be more feasible.
Influence of carrier confinement on the subthreshold swing of multigate silicon-on-insulator transistors
Authors: Colinge Jean-Pierre , Afzalian Aryan , Lee Chi-Woo , Yan Ran , Akhavan Nima Dehdashti
Published: April 2008

The minimum energy of the first conduction subband varies with gate voltage in trigate silicon-on-insulator metal-oxide-silicon field-effect transistors (MOSFETs) in subthreshold operation. In an inversion-mode trigate device, the energy level of the lowest subband increases with electron concentration, while it decreases under the same conditions in some accumulation-mode devices. As a result of this quantum effect, the subthreshold swing of accumulation-mode trigate FETs is smaller than predicted by classical theory. This effect is not observed in fin-shaped FETs and gate-all-around MOSFETs and can be amplified by modifying the device cross section.
Using the Delphi Technique in Normative Planning Research: Methodological Design Considerations
Authors: Novakowski Nick , Wellar Barry
Published: April 2008

Worldwide, metropolitan areas continue to be confronted by a growing number of increasingly difficult planning issues. It is our experience that planning practitioners have not taken full advantage of what the Delphi technique can contribute to making informed choices in a wide variety of decision and policy environments. The objectives of this paper are to describe and explain the research design that supported a real-world application of the Delphi technique in an urban, regional, and ecosystem-based planning context, as well as to demonstrate how this model has been or can be adapted to serve a variety of planning research or application tasks.
Transcranial Direct Current Stimulation and Visual Perception
Authors: Antal Andrea , Paulus Walter
Published: April 2008

Membrane potentials and spike sequences represent the basic modes of cerebral information processing. Both can be externally modulated in humans by quite specific techniques: transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS). These methods induce reversible circumscribed cortical excitability changes, either excitatory or inhibitory, outlasting stimulation in time. Experimental pharmacological interventions may selectively enhance the duration of the aftereffects. Whereas rTMS induces externally triggered changes in the neuronal spiking pattern and interrupts or excites neuronal firing in a spatially and temporally restricted fashion, tDCS modulates the spontaneous firing rates of neurons by changing resting-membrane potential. The easiest and most common way of evaluating the cortical excitability changes is by applying TMS to the motor cortex, since it allows reproducible quantification through the motor-evoked potential. Threshold determinations at the visual cortex or psychophysical methods usually require repeated and longer measurements and thus more time for each data set. Here, results derived from the use of tDCS in visual perception, including contrast as well as motion detection and visuo – motor coordination and learning, are summarised. It is demonstrated that visual functions can be transiently altered by tDCS, as has been shown for the motor cortex previously. Up- and down-regulation of different cortical areas by tDCS is likely to open a new branch in the field of visual psychophysics.
Perisaccadic Parietal and Occipital Gamma Power in Light and in Complete Darkness
Authors: Forgacs Peter B , von Gizycki Hans , Selesnick Ivan , Syed Nasir A , Ebrahim Kurt , Avitable Matt , Amassian Vahe , Lytton William , Bodis-Wollner Ivan
Published: April 2008

Our objective was to determine perisaccadic gamma range oscillations in the EEG during voluntary saccades in humans. We evaluated occipital perisaccadic gamma activity both in the presence and absence of visual input, when the observer was blindfolded. We quantified gamma power in the time periods before, during, and after horizontal saccades. The corresponding EEG was evaluated for individual saccades and the wavelet transformed EEG averaged for each time window, without averaging the EEG first. We found that, in both dark and light, parietal and occipital gamma power increased during the saccade and peaked prior to reaching new fixation. We show that this is not the result of muscle activity and not the result of visual input during saccades. Saccade direction affects the laterality of gamma power over posterior electrodes. Gamma power recorded over the posterior scalp increases during a saccade. The phasic modulation of gamma by saccades in darkness—when occipital activity is decoupled from visual input—provides electrophysiological evidence that voluntary saccades affect ongoing EEG. We suggest that saccade-phasic gamma modulation may contribute to short-term plasticity required to realign the visual space to the intended fixation point of a saccade and provides a mechanism for neuronal assembly formation prior to achieving the intended saccadic goal. The wavelet-transformed perisaccadic EEG could provide an electrophysiological tool applicable in humans for the purpose of fine analysis and potential separation of stages of ‘planning’ and ‘action’.
Top — Down Control of Visual Perception: Attention in Natural Vision
Authors: Rolls Edmund T
Published: April 2008

Top – down perceptual influences can bias (or pre-empt) perception. In natural scenes, the receptive fields of neurons in the inferior temporal visual cortex (IT) shrink to become close to the size of objects. This facilitates the read-out of information from the ventral visual system, because the information is primarily about the object at the fovea. Top – down attentional influences are much less evident in natural scenes than when objects are shown against blank backgrounds, though are still present. It is suggested that the reduced receptive-field size in natural scenes, and the effects of top – down attention contribute to change blindness. The receptive fields of IT neurons in complex scenes, though including the fovea, are frequently asymmetric around the fovea, and it is proposed that this is the solution the IT uses to represent multiple objects and their relative spatial positions in a scene. Networks that implement probabilistic decision-making are described, and it is suggested that, when in perceptual systems they take decisions (or ‘test hypotheses’), they influence lower-level networks to bias visual perception. Finally, it is shown that similar processes extend to systems involved in the processing of emotion-provoking sensory stimuli, in that word-level cognitive states provide top – down biasing that reaches as far down as the orbitofrontal cortex, where, at the first stage of affective representations, olfactory, taste, flavour, and touch processing is biased (or pre-empted) in humans.
Pre-Emptive Perception
Authors: Bodis-Wollner Ivan
Published: April 2008

How can an action to a target be selected without yet knowing what it is? Pre-emptive perception (PEP) is a framework which orders neuronal mechanisms in association with voluntary actions before an action is started and until it is completed. It is assumed that PEP serves the purpose of perception, but a conscious, perceptual identification of the goal is not obligatorily completed during the time period of PEP itself. The concept of PEP is that the brain pre-emptively optimizes an action plan to maximize eventual perception, even before being sure what the goal is.

Experimental studies of voluntary saccadic eye movements are considered as prototypic activity within the framework of PEP. The core concept of pre-emption is that a particular saccade is selected while a large number of other possible actions are deselected. Pre-emptive computations include mechanisms associated with internal context and reward. Neurophysiological studies which show anatomically and functionally separate cortical and some subcortical neuronal groups in computing saccades are summarized.

There is a potential relationship of PEP as a neurobiological framework and some philosophical concepts. Terms for processes between planning and action, such as intention, anticipation, and attention, are often incongruent in everyday language and in epistemology. It is proposed here that a scrutiny of these terms can be rigorously approached by temporal subdivision of PEP and conversely, clear definitions of these terms can lead to organized experimental designs of cognitive neurobiology. The temporal subdivision of PEP allows a critique of The Will in the definition of Schopenhauer and distinguishes it from the ‘free will’.
Killin is a p53-regulated nuclear inhibitor of DNA synthesis
Authors: Cho Yong-jig , Liang Peng
Published: April 2008

Cell growth arrest and apoptosis are two best-known biological functions of tumor-suppressor p53. However, genetic evidence indicates that not only is p21 the major mediator of G
1
arrest, but also it can prevent apoptosis with an unknown mechanism. Here, we report the discovery of a p53 target gene dubbed
killin
, which lies in close proximity to pten on human chromosome 10 and encodes a 20-kDa nuclear protein. We show that Killin is not only necessary but also sufficient for p53-induced apoptosis. Genetic and biochemical analysis demonstrates that Killin is a high-affinity DNA-binding protein, which potently inhibits eukaryotic DNA synthesis
in vitro
and appears to trigger S phase arrest before apoptosis
in vivo
. The DNA-binding domain essential for DNA synthesis inhibition was mapped to within 42 amino acid residues near the N terminus of Killin. These results support Killin as a missing link between p53 activation and S phase checkpoint control designed to eliminate replicating precancerous cells, should they escape G
1
blockade mediated by p21.
The role of filament-packing dynamics in powering amoeboid cell motility
Authors: Miao Long , Vanderlinde Orion , Liu Jun , Grant Richard P. , Wouterse Alan , Shimabukuro Katsuya , Philipse Albert , Stewart Murray , Roberts Thomas M.
Published: April 2008

Although several models have been proposed to account for how cytoskeleton polymerization drives protrusion in cell motility, the precise mechanism remains controversial. Here, we show that, in addition to force exerted directly against the membrane by growing filaments, the way elongating filaments pack also contributes to protrusion by generating an expansion of the cytoskeleton gel. Tomography shows that filament packing in the major sperm protein (MSP) -based nematode sperm-motility machinery resembles that observed with rigid rods. Maximum rod-packing density decreases dramatically as the rods lengthen. Therefore, as filaments elongate, the cytoskeleton gel expands to accommodate their packing less densely. This volume expansion combines with polymerization to drive protrusion. Consistent with this hypothesis, an engineered MSP mutant that generates shorter filaments shows higher filament-packing density and slower movement.
The thermal impulse response of
Escherichia coli
Authors: Paster Eli , Ryu William S.
Published: April 2008

Swimming
Escherichia coli
responds to changes in temperature by modifying its motor behavior. Previous studies using populations of cells have shown that
E. coli
accumulate in spatial thermal gradients, but these experiments did not cleanly separate thermal responses from chemotactic responses. Here we have isolated the thermal response by studying the behavior of single, tethered cells. The motor output of cells grown at 33°C was measured at constant temperature, from 10° to 40°C, and in response to small, impulsive increases in temperature, from 23° to 43°C. The thermal impulse response at temperatures < 31°C is similar to the chemotactic impulse response: Both follow a similar time course, share the same directionality, and show biphasic characteristics. At temperatures > 31°C, some cells show an inverted response, switching from warm- to cold-seeking behavior. The fraction of inverted responses increases nonlinearly with temperature, switching steeply at the preferred temperature of 37°C.
Serotonin is necessary for place memory in
Drosophila
Authors: Sitaraman Divya , Zars Melissa , LaFerriere Holly , Chen Yin-Chieh , Sable-Smith Alex , Kitamoto Toshihiro , Rottinghaus George E. , Zars Troy
Published: April 2008

Biogenic amines, such as serotonin and dopamine, can be important in reinforcing associative learning. This function is evident as changes in memory performance with manipulation of either of these signals. In the insects, evidence begins to argue for a common role of dopamine in negatively reinforced memory. In contrast, the role of the serotonergic system in reinforcing insect associative learning is either unclear or controversial. We investigated the role of both of these signals in operant place learning in
Drosophila
. By genetically altering serotonin and dopamine levels, manipulating the neurons that make serotonin and dopamine, and pharmacological treatments we provide clear evidence that serotonin, but not dopamine, is necessary for place memory. Thus, serotonin can be critical for memory formation in an insect, and dopamine is not a universal negatively reinforcing signal.
Regulation of polymerase exchange between Polη and Polδ by monoubiquitination of PCNA and the movement of DNA polymerase holoenzyme
Authors: Zhuang Zhihao , Johnson Robert E. , Haracska Lajos , Prakash Louise , Prakash Satya , Benkovic Stephen J.
Published: April 2008

To ensure efficient and timely replication of genomic DNA, organisms in all three kingdoms of life possess specialized translesion DNA synthesis (TLS) polymerases (Pols) that tolerate various types of DNA lesions. It has been proposed that an exchange between the replicative DNA Pol and the TLS Pol at the site of DNA damage enables lesion bypass to occur. However, to date the molecular mechanism underlying this process is not fully understood. In this study, we demonstrated in a reconstituted system that the exchange of
Saccharomyces cerevisiae
Polδ with Polη requires both the stalling of the holoenzyme and the monoubiquitination of proliferating cell nuclear antigen (PCNA). A moving Polδ holoenzyme is refractory to the incoming Polη. Furthermore, we showed that the Polη C-terminal PCNA-interacting protein motif is required for the exchange process. We also demonstrated that the second exchange step to bring back Polδ is prohibited when Lys-164 of PCNA is monoubiquitinated. Thus the removal of the ubiquitin moiety from PCNA is likely required for the reverse exchange step after the lesion bypass synthesis by Polη.
Effects of Old Age on Vascular Complexity and Dispersion of the Hepatic Sinusoidal Network
Authors: Warren Alessandra , Chaberek Slawomir , Ostrowski Kazimierz , Cogger Victoria C. , Hilmer Sarah N. , McCuskey Robert S. , Fraser Robin , Le Couteur David G.
Published: April 2008

Objectives: In old age, there are marked changes in both the structure of the liver sinusoidal endothelial cell and liver perfusion. The objective of this study was to determine whether there are also aging changes in the microvascular architecture and vascular dispersion of the liver that might influence liver function.

Methods: Vascular corrosion casts and light micrographs of young (4 months) and old (24 months) rat livers were compared. Fractal and Fourier analyses and micro‐computed tomography were used. Vascular dispersion was determined from the dispersion number for sucrose and 100‐nm microspheres in impulse response experiments.

Results: Age did not affect sinusoidal dimensions, sinusoidal density, or dispersion number. There were changes in the geometry and complexity of the sinusoidal network as determined by fractal dimension and degree of anisotropy.

Conclusions: There are small, age‐related changes in the architecture of the liver sinusoidal network, which may influence hepatic function and reflect broader aging changes in the microcirculation. However, sinusoidal dimensions and hepatic vascular dispersion are not markedly influenced by old age.
Real‐Time Contrast Imaging: A New Method to Monitor Capillary Recruitment in Human Forearm Skeletal Muscle
Authors: Mulder Alexandra H. , Van Dijk Arie P.J. , Smits Paul , Tack Cees J.
Published: April 2008

Objective: Muscle capillary perfusion can be measured by contrast‐enhanced ultrasound. We examined whether a less time‐consuming ultrasound technique, called “real‐time imaging,” could be used to measure capillary recruitment in human forearm skeletal muscle.

Methods: We measured microvascular blood volume and microvascular flow velocity using bolus injections of contrast microbubbles after forearm muscle exercise and a two‐hour infusion of insulin into the brachial artery (both associated with capillary recruitment) and after sodium nitroprusside infusion (no changes in flow distribution).

Results: After an intravenous bolus injection of the contrast agent, the steady‐state concentration of contrast agent in forearm muscle lasted long enough (approximately 190 seconds) for the duration of the measurements (which take 70–80 seconds), rendering the continuous infusion of microbubbles unnecessary. Microvascular blood‐volume measurements showed a good short‐time reproducibility and a good reproducibility after repositioning of the forearm. Reproducibility of microvascular flow velocity was too low. Exercise and insulin infusion both increased microvascular blood volume, consistent with capillary recruitment. Sodium nitroprusside had no effect.

Conclusion: Real‐time contrast imaging, after bolus injections of an ultrasound contrast agent, provides reliable information about capillary recruitment in human forearm skeletal muscle, and may offer a valuable tool in studying human (patho)physiology.