bluuebunny/crossref_metadata_2025 huggingface dataset:
LASER BEAT-WAVE BUNCHED BEAM FOR COMPACT SUPERRADIANCE SOURCES
Authors: HUANG YEN-CHIEH
Published: February 2007

A periodically bunched electron beam is useful for generating high-brightness electron superradiance. This paper studies the generation and acceleration of density-modulated electron beams from a photocathode electron gun driven by a laser beat wave. Computer simulation shows the feasibility of accelerating and preserving the density-modulated electron beam in an accelerator. This paper also details the implementation of a beat-wave laser system with a variable beat frequency for driving a photocathode electron gun.
GENERATION OF GOOD-QUALITY RELATIVISTIC ELECTRON BEAM FROM SELF-MODULATED LASER WAKEFIELD ACCELERATION
Authors: HAFZ N. , KIM G. H. , KIM C. , SUK H.
Published: February 2007

A relativistic electron bunch with a large charge (~2 nC ) was produced from a self-modulated laser wakefield acceleration configuration. In this experiment, an intense laser pulse with a peak power of 2 TW and a duration of 700 fs was focused in a nitrogen gas jet, and multi-MeV electrons were observed from the strong laser-plasma interaction. By passing the electrons through a small pinhole-like collimator of cone f/70, we observed a narrowing in the electron beam's energy spread. The beam clearly showed a small energy-spread behavior with a central energy of 4.8 MeV and a charge of 115 pC. The acceleration gradient was estimated to be about 20 GeV/m.
GENERATION OF ULTRA-SHORT ELECTRON BUNCHES FOR LIGHT SOURCE RESEARCH
Authors: WANG Y. C. , HSU S. Y. , HWANG C. S. , HWANG J. Y. , LAU W. K. , LIN F. Y. , YANG T. T. , RIMJAEM S.
Published: February 2007

An S-band thermionic 1.5-cell rf gun injector system is being built at NSRRC for Taiwan Photon Source (TPS) booster. At optimized field ratio, an electron beam with linear energy chirp can be generated by the rf gun. The beam is then compressed by an alpha magnet such that ultra-short electron bunches at femto-second bunch length can be obtained. Particle dynamics has been studied for an rf gun with nose cone at the cathode, simulation results show that 74 pC bunches at about 97 fs is achievable. Some of the critical components such as the rf gun and alpha magnet have been fabricated and being tested in house. Experiments for intense coherent THz radiations and tunable femto-second X-ray from ultra-short bunches are being proposed as future applications.
ELECTRON ACCELERATION IN A GLASS CAPILLARY AND ITS APPLICATION
Authors:   Collaborators: Y. Mori (National Institute of Radiation Science), K. Kondo, T. Norimatsu, S. Fukumochi, M. Kashihara, K. Kimura, T. Tanimoto, M. Tampa, K. Tsuji, N. Nakanii (ILE Osaka University) and Y. Sentoku (University of Nevada Reno)., KITAGAWA YONEYOSHI
Published: February 2007

The discussion how to accelerate electrons to GeV leads us to the concept of the capillary. The 40 TW laser with prepulses, guided into a 1 cm-long capillary has accelerated the electrons to 100 MeV. The prepulse-free PW laser was also guided into the longer capillary, which formed a 3 cm plasma channel, but the energy gain was only 40 MeV. The prepulse-free laser made it clear that the cone works as an electron seeder. Application of the capillary accelerator was finally discussed.
ION ACCELERATION USING CIRCULARLY POLARIZED PULSES: PHYSICS AND POSSIBLE APPLICATIONS
Authors: MACCHI ANDREA , CORNOLTI FULVIO
Published: February 2007

The acceleration of ions in the interaction of ultrashort, high intensity, circularly polarized laser pulses with overdense plasmas has been theoretically investigated. By using particle-in-cell (PIC) simulations it is found that high-density, short duration ion bunches moving into the plasma are promptly generated at the laser-plasma interaction surface. This regime is qualitatively different from ion acceleration regimes driven by fast electrons such as sheath acceleration at the rear side of the target. A simple analytical model accounts for the numerical observations and provides scaling laws for the ion bunch velocity and generation time as a function of pulse intensity and plasma density. The ion bunches have moderate energies (100 keV-1 MeV) but very high density and low beam divergence, and might be of interest for problems of ultrafast compression, acceleration or heating of high–density matter. In particular, we have studied their application to the development of compact sources of fusion neutrons. We analyzed two target schemes showing that intense neutron bursts with femtosecond duration are produced.
EARLY OUT-OF-EQUILIBRIUM BEAM-PLASMA EVOLUTION: POSSIBLE FORMATION OF A BEAM RING STRUCTURE
Authors: FIRPO M. C. , LIFSCHITZ A. F.
Published: February 2007

We solve analytically the out-of-equilibrium initial stage that follows the injection of a radially finite electron beam into a plasma at rest and test it against particle-in-cell simulations. For initial large beam edge gradients and not too large beam radius, compared to the electron skin depth, the electron beam is shown to evolve into a ring structure. For low enough transverse temperatures, filamentation instability eventually proceeds and saturates when transverse isotropy is reached. The analysis accounts for the variety of very recent experimental beam transverse observations.
RANK ONE CHAOS IN SWITCH-CONTROLLED MURALI–LAKSHMANAN–CHUA CIRCUIT
Authors: OKSASOGLU ALI , MA DONGSHENG , WANG QIUDONG
Published: February 2007

In this paper, we investigate the creation of strange attractors in a switch-controlled MLC (Murali–Lakshmanan–Chua) circuit. The design and use of this circuit is motivated by a recent mathematical theory of rank one attractors developed by Wang and Young. Strange attractors are created by periodically kicking a weakly stable limit cycle emerging from the center of a supercritical Hopf bifurcation, and are found in numerical simulations by following a recipe-like algorithm. Rigorous conditions for chaos are derived and various switch control schemes, such as synchronous, asynchronous, single-, and multi-pulse, are investigated in numerical simulations.
GLOBAL SYNCHRONIZATION IN AN ARRAY OF LINEARLY COUPLED DELAYED NEURAL NETWORKS WITH AN ARBITRARY COUPLING MATRIX
Authors: LU HONGTAO , CHEN GUANRONG
Published: February 2007

In this paper, we investigate global synchronization in an array of linearly coupled identical delayed neural networks. We consider the array with an arbitrary coupling matrix without assuming it to be symmetric, irreducible and diffusive. Moreover, we consider the array being connected through two different coupling schemes, state-coupling and output-coupling, respectively. For state-coupling, we derive a more general sufficient condition ensuring global synchronization, which is an extension of some existing results in the literature. For output-coupling, we derive a new sufficient condition for global synchronization. Numerical simulations are given to illustrate the theoretical results.
NEW ESTIMATIONS FOR GLOBALLY ATTRACTIVE AND POSITIVE INVARIANT SET OF THE FAMILY OF THE LORENZ SYSTEMS
Authors: YU PEI , LIAO XIAOXIN
Published: February 2007

In this paper, we employ generalized Lyapunov functions to derive new estimations of the ultimate boundary for the trajectories of two types of Lorenz systems, one with parameters in finite intervals and the other in infinite intervals. The new estimations improve the results reported so far in the literature. In particular, for the singular cases: b → 1+ and a → 0+, we have obtained the estimations independent of a. Moreover, our method using elementary algebra greatly simplifies the proofs in the literature. This is an interesting attempt in obtaining information of the attractors which is difficult when merely based on differential equations. It indicates that Lyapunov function is still a powerful tool in the study of qualitative behavior of chaotic systems.
SYMMETRIC PERIODIC ORBITS NEAR HETEROCLINIC LOOPS AT INFINITY FOR A CLASS OF POLYNOMIAL VECTOR FIELDS
Authors: CORBERA MONTSERRAT , LLIBRE JAUME
Published: February 2007

For polynomial vector fields in ℝ3, in general, it is very difficult to detect the existence of an open set of periodic orbits in their phase portraits. Here, we characterize a class of polynomial vector fields of arbitrary even degree having an open set of periodic orbits. The main two tools for proving this result are, first, the existence in the phase portrait of a symmetry with respect to a plane and, second, the existence of two symmetric heteroclinic loops.
OBSERVER-BASED ADAPTIVE FEEDBACK CONTROLLER OF A CLASS OF CHAOTIC SYSTEMS
Authors: BOULKROUNE ABDESSELEM , CHEKIREB HACHEMI , TADJINE MOHAMED , BOUATMANE SABRINA
Published: February 2007

In this paper, an observer-based adaptive feedback controller is developed for a class of chaotic systems. This controller does not need the availability of state variables. It can be used for tracking a smooth orbit that can be a limit cycle or a chaotic orbit of another system. This adaptive feedback controller is constructed with the aid of its H∞ control technique to achieve the H∞ tracking performance. Based on Lyapunov stability theorem, the proposed adaptive feedback control system can guarantee the stability of whole closed-loop system and obtain good tracking performance as well. To demonstrate the efficiency of the proposed scheme, two well-known chaotic systems, namely Chua's circuit and Lur'e system are considered as illustrative examples.
Comparative studies of the role of hormone-sensitive lipase and adipose triglyceride lipase in human fat cell lipolysis
Authors: Rydén Mikael , Jocken Johan , van Harmelen Vanessa , Dicker Andrea , Hoffstedt Johan , Wirén Mikael , Blomqvist Lennart , Mairal Aline , Langin Dominique , Blaak Ellen , Arner Peter
Published: February 2007

Hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) regulate adipocyte lipolysis in rodents. The purpose of this study was to compare the roles of these lipases for lipolysis in human adipocytes. Subcutaneous adipose tissue was investigated. HSL and ATGL protein expression were related to lipolysis in isolated mature fat cells. ATGL or HSL were knocked down by RNA interference (RNAi) or selectively inhibited, and effects on lipolysis were studied in differentiated preadipocytes or adipocytes derived from human mesenchymal stem cells (hMSC). Subjects were all women. There were 12 lean controls, 8 lean with polycystic ovary syndrome (PCOS), and 27 otherwise healthy obese subjects. We found that norepinephrine-induced lipolysis was positively correlated with HSL protein levels ( P < 0.0001) but not with ATGL protein. Women with PCOS or obesity had significantly decreased norepinephrine-induced lipolysis and HSL protein expression but no change in ATGL protein expression. HSL knock down by RNAi reduced basal and catecholamine-induced lipolysis. Knock down of ATGL decreased basal lipolysis but did not change catecholamine-stimulated lipolysis. Treatment of hMSC with a selective HSL inhibitor during and/or after differentiation in adipocytes reduced basal lipolysis by 50%, but stimulated lipolysis was inhibited completely. In contrast to findings in rodents, ATGL is of less importance than HSL in regulating catecholamine-induced lipolysis and cannot replace HSL when this enzyme is continuously inhibited. However, both lipases regulate basal lipolysis in human adipocytes. ATGL expression, unlike HSL, is not influenced by obesity or PCOS.
Somatostatin decreases voltage-gated Ca2+currents in GH3 cells through activation of somatostatin receptor 2
Authors: Yang Seung-Kwon , Parkington Helena C. , Epelbaum Jacques , Keating Damien J. , Chen Chen
Published: February 2007

The secretion of growth hormone (GH) is inhibited by hypothalamic somatostatin (SRIF) in somatotropes through five subtypes of the somatostatin receptor (SSTR1–SSTR5). We aimed to characterize the subtype(s) of SSTRs involved in the Ca2+current reduction in GH3 somatotrope cells using specific SSTR subtype agonists. We used nystatin-perforated patch clamp to record voltage-gated Ca2+currents, using a holding potential of −80 mV in the presence of K+and Na+channel blockers. We first established the presence of T-, L-, N-, and P/Q-type Ca2+currents in GH3 cells using a variety of channel blockers (Ni+, nifedipine, ω-conotoxin GVIA, and ω-agatoxin IVA). SRIF (200 nM) reduced L- and N-type but not T- or P/Q-type currents in GH3 cells. A range of concentrations of each specific SSTR agonist was tested on Ca2+currents to find the maximal effective concentration. Activation of SSTR2 with 10−7and 10−8M L-797,976 decreased the voltage-gated Ca2+current and abolished any further decrease by SRIF. SSTR1, SSTR3, SSTR4, and SSTR5 agonists at 10−7M did not modify the voltage-gated Ca2+current and did not affect the Ca2+current response to SRIF. These results indicate that SSTR2 is involved mainly in regulating voltage-gated Ca2+currents by SRIF, which contributes to the decrease in intracellular Ca2+concentration and GH secretion by SRIF.
Endotoxin attenuates growth hormone-induced hepatic insulin-like growth factor I expression by inhibiting JAK2/STAT5 signal transduction and STAT5b DNA binding
Authors: Chen Yu , Sun Difei , Krishnamurthy Vidya M. R. , Rabkin Ralph
Published: February 2007

Gram-negative sepsis with release of endotoxin is a frequent cause of cachexia that develops partly because of resistance to growth hormone (GH) with reduced insulin-like growth factor-I (IGF-I) expression. We set out to more fully characterize the mechanisms for the resistance and to determine whether in addition to a defect in the janus kinase 2 (JAK2)-signal transducer and activator of transcription (STAT) 5b pathway, required for GH-induced IGF-I expression, there might also be a more distal defect. Conscious rats were given endotoxin and studied 4 h later. In liver of these animals, GH-induced JAK2 and STAT5 phosphorylation was impaired and appeared to be caused, at least in part, by a marked increase in hepatic tumor necrosis factor-α and interleukin-6 mRNA expression accompanied by elevated levels of inhibitors of GH signaling, namely cytokine-inducible suppressors of cytokine signaling-1 and -3 and cytokine-inducible SH2 protein (CIS). Nuclear phosphorylated STAT5b levels were significantly depressed to 61% of the control values and represent a potential cause of the reduced GH-induced IGF-I expression. In addition, binding of phosphorylated STAT5b to DNA was reduced to an even greater extent and averaged 17% of the normal control value. This provides a further explanation for the impaired IGF-I gene transcription. Interestingly, when endotoxin-treated rats were treated with GH, there was a marked increase in proinflammatory cytokine gene expression in the liver. If such a response were to occur in humans, this might provide a partial explanation for the adverse effect of GH treatment reported in critically ill patients.
Dysregulated intracellular signaling impairs CTGF-stimulated responses in human mesangial cells exposed to high extracellular glucose
Authors: Furlong Fiona , Crean John , Thornton Laura , O'Leary Ronan , Murphy Madeline , Martin Finian
Published: February 2007

High ambient glucose activates intracellular signaling pathways to induce the expression of extracellular matrix and cytokines such as connective tissue growth factor (CTGF). Cell responses to CTGF in already glucose-stressed cells may act to transform the mesangial cell phenotype leading to the development of glomerulosclerosis. We analyzed cell signaling downstream of CTGF in high glucose-stressed mesangial cells to model signaling in the diabetic milieu. The addition of CTGF to primary human mesangial cells activates cell migration which is associated with a PKC-ζ-GSK3β signaling axis. In high ambient glucose basal PKC-ζ and GSK3β phosphorylation levels are selectively increased and CTGF-stimulated PKC-ζ and GSK3β phosphorylation was impaired. These effects were not induced by osmotic changes. CTGF-driven profibrotic cell signaling as determined by p42/44 MAPK and Akt phosphorylation was unaffected by high glucose. Nonresponsiveness of the PKC-ζ-GSK3β signaling axis suppressed effective remodeling of the microtubule network necessary to support cell migration. However, interestingly the cells remain plastic: modulation of glucose-induced PKC-β activity in human mesangial cells reversed some of the pathological effects of glucose damage in these cells. We show that inhibition of PKC-β with LY379196 and PKC-β siRNA reduced basal PKC-ζ and GSK3β phosphorylation in human mesangial cells exposed to high glucose. CTGF stimulation under these conditions again resulted in PKC-ζ phosphorylation and human mesangial cell migration. Regulation of PKC-ζ by PKC-β in this instance may establish PKC-ζ as a target for constraining the progression of mesangial cell dysfunction in the pathogenesis of diabetic nephropathy.
A Roadmap to functional genomics
Authors: Penn Raymond B. , Ortega Victor E. , Bleecker Eugene R.
Published: February 2007

In August 2006, the Center for Human Genomics of the Wake Forest University School of Medicine in Winston-Salem, NC, hosted the National Institutes of Health-sponsored Roadmap Course entitled Models and Technologies for Defining Phenotype. Twenty-four biomedical and genomic researchers from throughout the world and with varying degrees of experience in the genomics, biological, and biomedical engineering sciences were invited to participate as students in a comprehensive course dedicated to presenting and evaluating current and future approaches that can overcome the problems experienced to date in characterizing the functional consequences of gene variation. A total of 34 senior researchers from four different academic institutions served as course faculty and employed a pedagogical approach that emphasized hands-on workshops, demonstrations, and small group discussions and tasks. Through this report we convey the complex and formidable problems unique to genomics research as we attempt to link the field of genomic research to complex human diseases. Furthermore, we describe the logic and organization of a Roadmap Course designed to teach a diverse group of researchers a multi-disciplinary approach to addressing complex biomedical scenarios in the field of human genomics.
Gene profiling during regression of pressure overload-induced cardiac hypertrophy
Authors: Yang Dong Kwon , Choi Bo Youn , Lee Young-Hoon , Kim Young-Gyu , Cho Myeong-Chan , Hong Seong-Eui , Kim Do Han , Hajjar Roger J. , Park Woo Jin
Published: February 2007

Regression of cardiac hypertrophy and improvement of the functional capacity of failing hearts have reportedly been achieved by mechanical unloading in cardiac work. In this study, cardiac hypertrophy was first induced in rats by transverse aortic constriction and then mechanically unloaded by relieving the constriction after significant cardiac hypertrophy had developed. Hypertrophy was significantly regressed at the cellular and molecular levels at day 1, 3, and 7 after constriction relief. Gene profiling analysis revealed that 52 genes out of 9,911 genes probed on a gene array were specifically upregulated during the early regression period. Among these regression-induced genes, Eyes absent 2 ( eya2) was of particular interest because it is a transcriptional cofactor involved in mammalian organogenesis as well as Drosophila eye development. Adenovirus-mediated overexpression of eya2 in rat neonatal cardiomyocytes completely abrogated phenylephrine-induced development of cardiomyocyte hypertrophy as determined by cell size, sarcomere rearrangement and fetal gene re-expression. Our data strongly suggest that transcriptional programs distinct from those mediating cardiac hypertrophy may be operating during the regression of hypertrophy, and eya2 may be a key regulator of one of these programs.
On the Physical Aspect of Heraclitus' Psychology
Authors: Betegh Gábor
Published: February 2007

The paper first discusses the metaphysical framework that allows the soul's integration into the physical world. A close examination of B36, supported by the comparative evidence of some other early theories of the soul, suggests that the word psuchê could function as both a mass term and a count noun for Heraclitus. There is a stuff in the world, alongside other physical elements, that manifests mental functions. Humans, and possibly other beings, show mental functions in so far as they have a portion of that stuff. Turning to the physical characterization of the soul, the paper argues that B36 is entirely consistent with the ancient testimonies that say that psuchê for Heraclitus is exhalation. But exhalations cover all states of matter from the lowest moist part of atmospheric air to the fire of celestial bodies. If so, psuchê for Heraclitus is both air and fire. The fact that psuchê can manifest the whole range of physical properties along the dry-wet axis guarantees that souls can show different intellectual and ethical properties as well. Moreover, Sextus Empiricus, supported by some other sources, provides us with an answer how portions of soul stuff are individuated into individual souls. The paper closes with a brief discussion of the question whether, and if so with what qualifications, we can apply the term 'physicalism' to Presocratic theories of the soul.
Tides and the Climate: Some Speculations
Authors: Munk Walter , Bills Bruce
Published: February 2007

The important role of tides in the mixing of the pelagic oceans has been established by recent experiments and analyses. The tide potential is modulated by long-period orbital modulations. Previously, Loder and Garrett found evidence for the 18.6-yr lunar nodal cycle in the sea surface temperatures of shallow seas. In this paper, the possible role of the 41 000-yr variation of the obliquity of the ecliptic is considered. The obliquity modulation of tidal mixing by a few percent and the associated modulation in the meridional overturning circulation (MOC) may play a role comparable to the obliquity modulation of the incoming solar radiation (insolation), a cornerstone of the Milanković theory of ice ages. This speculation involves even more than the usual number of uncertainties found in climate speculations.
Decadal Spinup of the South Pacific Subtropical Gyre
Authors: Roemmich D. , Gilson J. , Davis R. , Sutton P. , Wijffels S. , Riser S.
Published: February 2007

An increase in the circulation of the South Pacific Ocean subtropical gyre, extending from the sea surface to middepth, is observed over 12 years. Datasets used to quantify the decadal gyre spinup include satellite altimetric height, the World Ocean Circulation Experiment (WOCE) hydrographic and float survey of the South Pacific, a repeated hydrographic transect along 170°W, and profiling float data from the global Argo array. The signal in sea surface height is a 12-cm increase between 1993 and 2004, on large spatial scale centered at about 40°S, 170°W. The subsurface datasets show that this signal is predominantly due to density variations in the water column, that is, to deepening of isopycnal surfaces, extending to depths of at least 1800 m. The maximum increase in dynamic height is collocated with the deep center of the subtropical gyre, and the signal represents an increase in the total counterclockwise geostrophic circulation of the gyre, by at least 20% at 1000 m. A comparison of WOCE and Argo float trajectories at 1000 m confirms the gyre spinup during the 1990s. The signals in sea surface height, dynamic height, and velocity all peaked around 2003 and subsequently began to decline. The 1990s increase in wind-driven circulation resulted from decadal intensification of wind stress curl east of New Zealand—variability associated with an increase in the atmosphere’s Southern Hemisphere annular mode. It is suggested (based on altimetric height) that midlatitude gyres in all of the oceans have been affected by variability in the atmospheric annular modes on decadal time scales.
Is the World Ocean Warming? Upper-Ocean Temperature Trends: 1950–2000
Authors: Harrison D. E. , Carson Mark
Published: February 2007

Subsurface temperature trends in the better-sampled parts of the World Ocean are reported. Where there are sufficient observations for this analysis, there is large spatial variability of 51-yr trends in the upper ocean, with some regions showing cooling in excess of 3°C, and others warming of similar magnitude. Some 95% of the ocean area analyzed has both cooled and warmed over 20-yr subsets of this period. There is much space and time variability of 20-yr running trend estimates, indicating that trends over a decade or two may not be representative of longer-term trends. Results are based on sorting individual observations in World Ocean Database 2001 into 1° × 1° and 2° × 2° bins. Only bins with at least five observations per decade for four of the five decades since 1950 are used. Much of the World Ocean cannot be examined from this perspective. The 51-yr trends significant at the 90% level are given particular attention. Results are presented for depths of 100, 300, and 500 m. The patterns of the 90% significant trends are spatially coherent on scales resolved by the bin size. The vertical structure of the trends is coherent in some regions, but changes sign between the analysis depths in a number of others. It is suggested that additional attention should be given to uncertainty estimates for basin average and World Ocean average thermal trends.
Antarctic Circumpolar Current Transport Variability during 2003–05 from GRACE
Authors: Zlotnicki Victor , Wahr John , Fukumori Ichiro , Song Yuhe T.
Published: February 2007

Gravity Recovery and Climate Experiment (GRACE) gravity data spanning January 2003–November 2005 are used as proxies for ocean bottom pressure (BP) averaged over 1 month, spherical Gaussian caps 500 km in radius, and along paths bracketing the Antarctic Circumpolar Current’s various fronts. The GRACE BP signals are compared with those derived from the Estimating the Circulation and Climate of the Ocean (ECCO) ocean modeling–assimilation system, and to a non-Boussinesq version of the Regional Ocean Model System (ROMS). The discrepancy found between GRACE and the models is 1.7 cmH2O (1 cmH2O ∼ 1 hPa), slightly lower than the 1.9 cmH2O estimated by the authors independently from propagation of GRACE errors. The northern signals are weak and uncorrelated among basins. The southern signals are strong, with a common seasonality. The seasonal cycle GRACE data observed in the Pacific and Indian Ocean sectors of the ACC are consistent, with annual and semiannual amplitudes of 3.6 and 0.6 cmH2O (1.1 and 0.6 cmH2O with ECCO), the average over the full southern path peaks (stronger ACC) in the southern winter, on days of year 197 and 97 for the annual and semiannual components, respectively; the Atlantic Ocean annual peak is 20 days earlier. An approximate conversion factor of 3.1 Sv (Sv ≡ 106 m3 s−1) of barotropic transport variability per cmH2O of BP change is estimated. Wind stress data time series from the Quick Scatterometer (QuikSCAT), averaged monthly, zonally, and over the latitude band 40°–65°S, are also constructed and subsampled at the same months as with the GRACE data. The annual and semiannual harmonics of the wind stress peak on days 198 and 82, respectively. A decreasing trend over the 3 yr is observed in the three data types.
Comparison of the effectiveness of two programmes on older adults at risk of falling: unsupervised home exercise and supervised group exercise
Authors: Donat Hülya , Özcan Ayşe
Published: February 2007

Objective: To compare the effectiveness of unsupervised home and supervised group exercise on parameters related to risk of falling among older adults.

Design: Prospective, single-blind, randomized and controlled trial.

Setting: Nursing home.

Subjects: The subjects were selected from 535 independent individuals who resided in a nursing home. Forty-two older adults, aged > 65 years, with risk of falling were recruited, and 32 of them completed the study.

Intervention: The 42 subjects were divided into two groups (unsupervised home exercise and supervised exercise group) randomly. Exercise sessions were performed three times a week for a period of eight weeks.

Main measures: Measurements were taken at baseline and after the completion of the exercise programme. The fear of falling was evaluated using a visual analogue scale, quadriceps muscle strength was measured with a dynamometer, flexibility was assessed with the sit and reach test, functional mobility was determined using the Timed Up and Go Test, balance was evaluated using one-leg and tandem standing, and Berg Balance Scale and proprioception was assessed with knee position sense.

Results: Thirty-two subjects (unsupervised home exercise n = 15, supervised group exercise n = 17) completed the exercise programme and all of the measurements. The unsupervised home exercise group showed significant improvement in balance, functional mobility and flexibility (P > 0.05). In addition to balance, functional mobility and flexibility, the supervised exercise group also showed significant improvements in both strength and proprioception (P > 0.05).

Conclusions: Supervised group exercise is more effective at reducing the risk factors related to falling among older adults living in a nursing home than is unsupervised home exercise.
Development and validation of the Generalized Anxiety Disorder Inventory (GADI)
Authors: Argyropoulos Spilios V. , Ploubidis George B. , Wright Tamsin S. , Palm Marisha E. , Hood Sean D. , Nash Jon R. , Taylor A. Clare , Forshall Sam W. , Anderson Ian M. , Nutt David J. , Potokar John P.
Published: February 2007

The psychometric tools used for the assessment of generalized anxiety disorder (GAD) either do not conform to the current concept of the condition or have important limitations. We aimed to develop and validate a new questionnaire for the assessment of symptom profile and severity of GAD.

An original pool of potential scale items was subjected to a series of studies in non-clinical and clinical populations, in order to determine the final composition of the scale. The psychometric properties of the new scale, the Generalized Anxiety Disorder Inventory (GADI), were evaluated using a factor analytic model suitable for ordinal data and the Graded Response Model. The precision of measurement of the GADI was quantified through the item information functions.

A total of 197 outpatients and 522 non-clinical subjects participated in four studies and completed the GADI. The final 18-item scale was derived from an original pool of 30 potential items. The GADI showed good reliability, convergent and divergent validity. The scale comprises three factors, relating to cognitive, somatic and sleep symptoms. It accurately distinguished GAD patients from non-patient controls. The cognitive factor also distinguished GAD from other anxiety disorders and depression.

The GADI is a useful tool in the assessment of the breadth of symptoms and the severity of generalized anxiety disorder in clinical settings.
Waste management and recycling practices of the urban poor: a case study in Kuala Lumpur city, Malaysia
Authors: Murad Wahid , Siwar Chamhuri
Published: February 2007

This study assesses waste management and recycling practices of the urban poor households residing as squatters and in low cost flats of Kuala Lumpur city, Malaysia. To attain the objective, the study employed some statistical techniques such as t-tests of equality of means, one-way analysis of variance, chisquared ‘likelihood ratio’ tests, and simple descriptive statistics. The statistical techniques were used to determine and analyse the factors that significantly influence the environmental behaviour of the urban poor concerning solid waste management, particularly their recycling practices. The findings of the study show that the urban poor and low-income communities have been proved to behave in ways that are consistent with and conducive to environmentally friendly solid waste management. This study provides evidence that the urban poor and low-income communities are the main recyclers, re-users, and source-reducers of their household solid waste. The study, however, suggests that policies should be formulated to focus on promoting knowledge, education, and the skills of the urban poor and, in addition, to empower them as a means of improving their quality of life.
HIV Infection Among Transport Workers Operating Through Siliguri-Guwahati National Highway, India
Authors: Bal Baishali , Ahmed Syed Iftikar , Mukherjee Rita , Chakraborty Sekhar , Niyogi Swapan Kumar , Talukder Arunangshu , Chakraborty Nilanjan , Sarkar Kamalesh
Published: February 2007

A community-based cross-sectional study was conducted in July 2004 to understand the problem of HIV and other sexually transmitted infections among long-distance transport workers operating through the Siliguri-Guwahati national highway. The study included 301 transport workers who were contacted at different transport workers’ stops on the Siliguri-Guwahati national highway. Informed consent was obtained. Participants were interviewed for their socio-demographic characteristics, risk behavior, and risk perceptions. Blood testing for HIV, hepatitis B virus, and syphilis (at least 1:8 dilution) showed seroprevalence rates of 2.3%, 3.7%, and 6.3%, respectively. About 67% said they visited sex workers. The reported condom use rate was 58%. About 27% sustained a sexually transmitted infection within the last year. The existing HIV prevalence among transport workers appears to be low, but in view of their risk behavior and high rate of sexually transmitted infection, HIV rates may increase unless a suitable behavioral intervention is urgently initiated toward them.
Antiretroviral Treatment Literacy Among HIV Voluntary Counseling and Testing Clients in Moshi, Tanzania, 2003 to 2005
Authors: Landman Keren Z. , Thielman Nathan M. , Mgonja Anna , Shao Humphrey J. , Itemba Dafrosa K. , Ndosi Evelyn M. , Tribble Alison C. , Shao John F. , Bartlett John A. , Crump John A.
Published: February 2007

Antiretroviral treatment literacy leads to greater HIV testing and treatment and antiretroviral treatment adherence. Among northern Tanzanian subjects, antiretroviral treatment awareness was only 17%. Factors associated with low antiretroviral treatment literacy included having exchanged money or gifts for sex, living in rural areas, having more than 2 children, and having a primary education only. Previous HIV testing was protective against low antiretroviral treatment literacy. These results support refocusing HIV education efforts and increasing synergy between HIV prevention and treatment programs.
Evidence that the Pim1 kinase gene is a direct target of HOXA9
Authors: Hu Yu-Long , Passegué Emmanuelle , Fong Stephen , Largman Corey , Lawrence Hugh Jeffrey
Published: February 2007

The HOXA9 homeoprotein exerts dramatic effects in hematopoiesis. Enforced expression of HOXA9 enhances proliferation of primitive blood cells, expands hematopoietic stem cells (HSCs), and leads to myeloid leukemia. Conversely, loss of HOXA9 inhibits proliferation and impairs HSC function. The pathways by which HOXA9 acts are largely unknown, and although HOXA9 is a transcription factor, few direct target genes have been identified. Our previous study suggested that HOXA9 positively regulates Pim1, an oncogenic kinase. The hematologic phenotypes of Hoxa9- and Pim1-deficient animals are strikingly similar. Here we show that HOXA9 protein binds to the Pim1 promoter and induces Pim1 mRNA and protein in hematopoietic cells. Pim1 protein is diminished in Hoxa9−/− cells, and Hoxa9 and Pim1 mRNA levels track together in early hematopoietic compartments. Induction of Pim1 protein by HOXA9 increases the phosphorylation and inactivation of the proapoptotic BAD protein, a target of Pim1. Hoxa9−/− cells show increased apoptosis and decreased proliferation, defects that are ameliorated by reintroduction of Pim1. Thus Pim1 appears to be a direct transcriptional target of HOXA9 and a mediator of its antiapoptotic and proproliferative effects in early cells. Since HOXA9 is frequently up-regulated in acute myeloid leukemia, Pim1 may be a therapeutic target in human disease.
β-Trcp mediates ubiquitination and degradation of the erythropoietin receptor and controls cell proliferation
Authors: Meyer Laure , Deau Bénédicte , Forejtníková Hana , Duménil Dominique , Margottin-Goguet Florence , Lacombe Catherine , Mayeux Patrick , Verdier Frédérique
Published: February 2007

Control of intensity and duration of erythropoietin (Epo) signaling is necessary to tightly regulate red blood cell production. We have recently shown that the ubiquitin/proteasome system plays a major role in the control of Epo-R signaling. Indeed, after Epo stimulation, Epo-R is ubiquitinated and its intracellular part is degraded by the proteasome, preventing further signal transduction. The remaining part of the receptor and associated Epo are internalized and degraded by the lysosomes. We show that β-Trcp is responsible for Epo-R ubiquitination and degradation. After Epo stimulation, β-Trcp binds to the Epo-R. This binding, like Epo-R ubiquitination, requires Jak2 activation. The Epo-R contains a typical DSG binding sequence for β-Trcp that is highly conserved among species. Interestingly, this sequence is located in a region of the Epo-R that is deleted in patients with familial polycythemia. Mutation of the serine residue of this motif to alanine (Epo-RS462A) abolished β-Trcp binding, Epo-R ubiquitination, and degradation. Epo-RS462A activation was prolonged and BaF3 cells expressing this receptor are hypersensitive to Epo, suggesting that part of the hypersensitivity to Epo in familial polycythemia could be the result of the lack of β-Trcp recruitment to the Epo-R.
Exclusion of activeMycobacterium tuberculosiscomplex infection with the T-SPOTTM.TBassay
Authors: van Leeuwen R. M. L. , Bossink A. W. J. , Thijsen S. F. T.
Published: February 2007

The present brief report describes four cases with mycobacterial infection and negative T-SPOTTM.TBtests. This test proved to be a useful tool to help rule out the diagnosis of activeMycobacterium tuberculosisinfection and could therefore prevent unnecessary or inappropriate therapy.
The coding/non-coding overlapping architecture of the gene encoding the Drosophila pseudouridine synthase
Authors: Riccardo Sara , Tortoriello Giuseppe , Giordano Ennio , Turano Mimmo , Furia Maria
Published: February 2007

Background

In eukaryotic cells, each molecule of H/ACA small nucleolar RNA (snoRNA) assembles with four evolutionarily conserved core proteins to compose a specific ribonucleoprotein particle. One of the four core components has pseudouridine synthase activity and catalyzes the conversion of a selected uridine to pseudouridine. Members of the pseudouridine synthase family are highly conserved. In addition to catalyzing pseudouridylation of target RNAs, they carry out a variety of essential functions related to ribosome biogenesis and, in mammals, to telomere maintenance. To investigate further the molecular mechanisms underlying the expression of pseudouridine synthase genes, we analyzed the transcriptional activity of the Drosophila member of this family in great detail.

Results

The Drosophila gene for pseudouridine synthase, minifly/Nop60b (mfl), encodes two novel mRNAs ending at a downstream poly(A) site. One species is characterized only by an extended 3'-untranslated region (3'UTR), while a minor mRNA encodes a variant protein that represents the first example of an alternative subform described for any member of the family to date. The rare spliced variant is detected mainly in females and is predicted to have distinct functional properties. We also report that a cluster comprising four isoforms of a C/D box snoRNA and two highly related copies of a small ncRNA gene of unknown function is intron-encoded at the gene-variable 3'UTRs. Because this arrangement, the alternative 3' ends allow mfl not only to produce two distinct protein subforms, but also to release different ncRNAs. Intriguingly, accumulation of all these intron-encoded RNAs was found to be sex-biased and quantitatively modulated throughout development and, within the ovaries, the ncRNAs of unknown function were found not ubiquitously expressed.

Conclusion

Our results expand the repertoire of coding/non-coding transcripts derived from the gene encoding Drosophila pseudouridine synthase. This gene exhibits a complex and interlaced organization, and its genetic information may be expressed as different protein subforms and/or ncRNAs that may potentially contribute to its biological functions.
Nidogen 1 and 2 gene promoters are aberrantly methylated in human gastrointestinal cancer
Authors: Ulazzi Linda , Sabbioni Silvia , Miotto Elena , Veronese Angelo , Angusti Angela , Gafà Roberta , Manfredini Stefano , Farinati Fabio , Sasaki Takako , Lanza Giovanni , Negrini Massimo
Published: February 2007

Background

Nidogens are highly conserved proteins of basement membranes. Two nidogen proteins, nidogen 1 and nidogen 2, are known in mammals.

Results

We show that CpG islands of both NID1 and NID2 genes are aberrantly methylated in human cancer samples and cancer cell lines. For both genes, methylation was correlated with loss of gene transcription in human cell lines. Furthermore, demethylation of the NID1 and NID2 promoters restored gene transcription, demonstrating that methylation was responsible for silencing nidogen genes. In primary tumors, we detected NID1 promoter methylation in 67% of colon cancer samples and in 90% of gastric cancers. NID2 promoter was methylated in 29% of colon and 95% of gastric cancers. Immuno-staining for nidogen-2 confirmed the correlation between aberrant methylation and loss of nidogen expression also in primary tumors, implying that aberrant methylation was a mechanism for inhibiting nidogens expression in human gastrointestinal tumors.

Conclusion

These results suggest that loss of nidogens expression has a potential pathogenetic role in colon and stomach tumorigenesis. Nidogens are believed to connect laminin and collagen IV networks, hence stabilizing the basement membrane structure. Nidogens are also important for cell adhesion, as they establish contacts with various cellular integrins. Loss of nidogen expression may favor invasion and metastasis of cancer cells by loosening cell interaction with basal membrane and by weakening the strength of the basement membrane itself, first barrier from the connective vascularized matrix.
Expression of kinin B1 and B2 receptors in immature, monocyte-derived dendritic cells and bradykinin-mediated increase in intracellular Ca2+ and cell migration
Authors: Bertram Cornelia M , Baltic Svetlana , Misso Neil L , Bhoola Kanti D , Foster Paul S , Thompson Philip J , Fogel-Petrovic Mirjana
Published: February 2007

The kinins, bradykinin (BK) and Lys-des[Arg9]-BK, are important inflammatory mediators that act via two specific G protein-coupled kinins, B1 and B2 receptors (B2R). Kinins influence the activity of immune cells by stimulating the synthesis of cytokines, eicosanoids, and chemotactic factors. Whether human dendritic cells (DC) express kinin receptors and whether kinins influence DC function are unknown. Fluorescence immunocytochemistry and RT-PCR were used to demonstrate that immature human monocyte-derived DC (hMo-DC) constitutively expressed kinins B1R and B2R. Kinin receptor expression was induced on the 3rd and 4th days of culture during differentiation of hMo-DC from monocytes and was not dependent on the presence of IL-4 or GM-CSF. Although monocytes also expressed B2R mRNA, the protein was not detected. The kinin agonists BK and Lys-des[Arg9]-BK up-regulated the expression of their respective receptors. BK, acting via the B2R, increased intracellular Ca2+, as visualized by confocal microscopy using the fluorescent Ca2+ dye, Fluor-4 AM. Evaluation of migration in Trans-well chambers demonstrated significant enhancement by BK of migration of immature hMo-DC, which was B2R-dependent. However, kinins did not induce maturation of hMo-DC. The novel finding that kinin receptors are constitutively expressed in immature hMo-DC suggests that these receptors may be expressed in the absence of proinflammatory stimuli. BK, which increases the migration of immature hMo-DC in vitro, may play an important role in the migration of immature DC in noninflammatory conditions and may also be involved in the recruitment of immature DC to sites of inflammation.
Native and fragmented fibronectin oppositely modulate monocyte secretion of MMP-9
Authors: Marom Barak , Rahat Michal A , Lahat Nitza , Weiss-Cerem Lea , Kinarty Amalia , Bitterman Haim
Published: February 2007

Monocytes remodel the extracellular matrix (ECM) by secreting proteins composing the ECM such as fibronectin (FN) and degrading proteases such as matrix metalloproteinase-9 (MMP-9), which cleaves FN into fragments. The effects of FN and its fragmented products on the expression of monocyte MMP-9 are controversial and largely unknown. We showed that in human monocytes, the proinflammatory cytokine TNF-α induced MMP-9 secretion and increased fragmentation of FN into distinct fragments. When primary monocytes or the U937 monocytic cell line were incubated on a plastic substrate, plastic-coated with native FN, and plastic-coated with fragmented FN (frag-FN), native FN inhibited TNF-α-induced proMMP-9 secretion by twofold (P<0.01) compared with plastic or frag-FN. Exploration of the dynamics of inflammation by incubating cells sequentially on the three substrates showed that frag-FN opposed the inhibitory effect of native FN. Inhibition of proMMP-9 by native FN was exerted at the translational level, as no change in MMP-9 mRNA, intracellular protein accumulation, or proteomic degradation was observed, and when degradation was blocked, no de novo translation of MMP-9 could be measured. We also showed that the reduction of MMP-9 secretion by native FN was responsible for attenuated migration of U937 cells (P<0.05). We suggest that in the inflammatory tissue, intact, native FN has a homeostatic role in harnessing MMP-9 activity. However, as fragmented products accumulate locally, they alleviate the inhibition and enable faster migration of the monocytes through the degraded ECM.
Service innovation: policing mental health – the St Andrew's scheme
Authors: Mann Alison , Sugarman Philip , Rooney Carol , Goodman Mary , Lynch Jim
Published: February 2007

Assaults against healthcare staff have gained increasing attention, prompting the Zero Tolerance Zone campaign in the National Health Service (NHS) (Department of Health, 1999). This advised that treatment could be withheld as a sanction, although not from ‘anyone who is mentally ill or under the influence of drugs'. More recently the NHS Security Management Service (Department of Health, 2005) found that the greatest number of assaults (over 43 000) were found in mental health and learning disability environments.