bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of sputtering conditions on microstructure and mechanical properties of Zr–Si–N films prepared by radio-frequency-reactive sputtering
Authors: Zhou M. , Nose M. , Deguchi Y. , Mae T. , Nogi K.
Published: September 2003

ZrN and ZrSiN films were prepared in an rf-sputtering apparatus which has a pair of targets facing each other (referred to as the facing target-type rf sputtering). In order to investigate the influence of substrate temperature on the structure and mechanical properties of Zr–Si–N films, the substrate temperature during the deposition was changed from 373 K to 673 K. Only one phase with a cubic B1 NaCl structure, typical for ZrN, can be clearly identified in all Zr–Si–N films in this study. Increasing substrate temperature can improve crystalline quality in all Zr–Si–N films in this study. Grain sizes of all Zr–Si–N thin films, despite the Si content, increase linearly with increasing substrate temperature. However, the grain growth speed with increasing substrate temperature in a pure ZrN thin film is much faster than that in Zr–Si–N thin films, because Si atom occupation of interstitial sites tends to lock diffusion paths and thus stabilize the structure. The hardness of Zr–Si–N films with low Si content, such as 3 at. % Si, decreases after the substrate temperature increases above 600 K because the internal stress drops. In the high Si content Zr–Si–N films, the hardness improved by increasing substrate temperature due to the increased strength in the grain boundaries.
Transition from reciprocal-space to real-space surface science—advent of the scanning tunneling microscope
Authors: Lagally Max G.
Published: September 2003

The emergence of surface science as an identifiable field of research depended to a large measure on structural determinations, which were dominated in the early days by diffraction methods. The scanning tunneling microscope enabled a transition to real-space imaging, making surface science visual and thus much more accessible. The evolution of surface structural determination is roughly traced from its inception to the present, where both diffraction and scanning tunneling microscopy have become commodities: Must haves for the serious surface scientist.
Vacuum science and technology: 1950–2003
Authors: Redhead P. A.
Published: September 2003

The “new vacuum technology” began in 1950 with the development of the Bayard–Alpert gauge which ended the limitation on the lowest measurable pressure that had existed for more than two decades. This led to the development of ultrahigh vacuum technology and the conversion of vacuum methodology from an art to a science. The Committee on Vacuum Technology, which was the precursor to the American Vacuum Society (AVS), was born three years later. This article considers the history, and possible future, of vacuum science and technology, and serves to introduce the following five articles which review the major advances in vacuum science and technology during the 50 years of the lifetime of the AVS.
Chemical methods of thin film deposition: Chemical vapor deposition, atomic layer deposition, and related technologies
Authors: Crowell John E.
Published: September 2003

This article provides a brief overview of thin film growth utilizing the reactive processes of chemical vapor deposition (CVD) and atomic layer deposition (ALD). In CVD, thin films are deposited upon the chemical reaction of vapor phase precursors with a solid surface. ALD is a surface reaction-controlled variant of CVD in which the chemical precursors are introduced in a sequential, pulsed manner, resulting in the growth of a self-limited monolayer (or less) film for each pulse step. The aim of both methodologies is the controlled growth of thin films with desired and reproducible properties. Emphasis is given to the latest advancements and future directions, and the processes and precursors commonly used to achieve controlled deposition.
Toy models for the falling chimney
Authors: Varieschi Gabriele , Kamiya Kaoru
Published: September 2003

In this paper we review the theory of the “falling chimney,” which deals with the breaking in mid-air of tall structures when they fall to the ground. We show that these ruptures can be caused by either shear forces typically developing near the base, or by the bending of the structure which is caused primarily by the internal bending moment. In the latter case the breaking is more likely to occur between one-third and one-half of the height of the chimney. Small scale toy models are used to reproduce the dynamics of the falling chimney. By examining photos taken during the fall of these models we test the adequacy of the theory. This type of experiment, which is easy to perform and conceptually challenging, can become part of a rotational mechanics lab for undergraduate students.
Using image recognition to automate video analysis of physical processes
Authors: Riera Jaime , Monsoriu Juan A. , Giménez Marcos H. , Hueso José L. , Torregrosa Juan R.
Published: September 2003

Multimedia technologies and video analysis allow the design of low-cost physical measurement and data acquisition systems. The number of pixels in the images limits their spatial resolution, whereas their time resolution depends on the number of frames recorded per second. Both characteristics are determined by the video recording system used. We have developed a laboratory system with these characteristics where important improvements have been reached by using image recognition to automate video analysis. In the present work we first examine several image recognition techniques and evaluate them from the point of view of their application to measurement systems. Then we describe the proposed system and the methodology followed in the measurement process. An image of an experimental object is recorded and used as a filter, while the sequence of images of that object in motion become the input frames for the recognition process. Finally, we discuss the results obtained by this measurement process and compare them with those obtained by using traditional measurement techniques.
Graphical computing in the undergraduate laboratory: Teaching and interfacing with LabVIEW
Authors: Moriarty P. J. , Gallagher B. L. , Mellor C. J. , Baines R. R.
Published: September 2003

We describe the development and implementation of an undergraduate physics laboratory course based on National Instruments’ LabVIEW application. LabVIEW, a graphical programming language, provides an intuitive interface with which to teach fundamental computer-based data acquisition techniques. To convey the importance of these techniques in modern experimental physics, during our course the students complete a variety of tasks and experiments based around LabVIEW virtual instruments that they have constructed. Furthermore, LabVIEW is a powerful signal processing and waveform analysis tool, it may be used to reinforce core physics concepts taught in an analytical fashion in other courses. Foremost among these is Fourier analysis. We discuss the efficacy of LabVIEW as a pedagogical tool in a number of Fourier-related areas. Other important pure and applied physics topics covered in our LabVIEW course and briefly described here include resonance, filtering and lock-in techniques, thermal diffusivity, chaos, and optical absorption in solids.
Orientation of Asymmetric Stem Cell Division by the APC Tumor Suppressor and Centrosome
Authors: Yamashita Yukiko M. , Jones D. Leanne , Fuller Margaret T.
Published: September 2003

Stem cell self-renewal can be specified by local signals from the surrounding microenvironment, or niche. However, the relation between the niche and the mechanisms that ensure the correct balance between stem cell self-renewal and differentiation is poorly understood. Here, we show that dividing
Drosophila
male germline stem cells use intracellular mechanisms involving centrosome function and cortically localized Adenomatous Polyposis Coli tumor suppressor protein to orient mitotic spindles perpendicular to the niche, ensuring a reliably asymmetric outcome in which one daughter cell remains in the niche and self-renews stem cell identity, whereas the other, displaced away, initiates differentiation.
Alkyl substituent effect on the polarity of phenols-tri-n-alkylamine complexes
Authors: Pawelka Zbigniew , Zeegers-Huyskens Therese
Published: September 2003

The formation constants and the dipole moments of the H-bonded adducts of 1:1 and 2:1 stoichiometries formed between three different phenols (phenol, 2,4,6-trichlorophenol, and 2,4-dinitrophenol) and different tri-n-alkylamines are determined in solvents of weak polarity. The polarity of the 1:1 complexes of 2,4,6-trichlorophenol with tri-n-alkylamines markedly increases with increasing degree of amine alkylation, in contrast with the complexes involving the two other phenols. The influence of the basicity and steric hindrance of the tri-n-alkylamines on the proton-transfer constant is discussed and quantitative correlations are deduced.Key words: phenols, tri-n-alkylamines, H-bonded complexes, proton transfer, polarity, steric effect.
Imitation Dynamic and Nash Equilibrium in Cournot Oligopoly with Capacities
Authors: Possajennikov Alex
Published: September 2003

The paper considers an imitation dynamic in the context of Cournot oligopoly. The pure "imitate-the-best" behavior can lead to an outcome inconsistent with Cournot-Nash equilibrium. The paper extends purely imitative behavior to imperfect imitation in the two-stage model with capacities and prices. This variation in the imitative behavior improves efficiency and makes the Cournot-Nash equilibrium a possible outcome of the dynamic imitation process.
Ulcerative Colitis in Kuwait: A Review of 90 Cases
Authors: Al-Shamali Mohammed A. , Kalaoui Maher , Patty Istivan , Hasan Fuad , Khajah Abdulkareem , Al-Nakib Basil
Published: September 2003

Background: Chronic ulcerative colitis is a disease of unknown etiology. Its incidence is on the rise in various developing countries as has been reported in studies from South-East Asia and the Middle East. There seems to be significant differences in the pattern and the clinical course of this disease in our patient population. The aim of our study is to assess the incidence and the clinical course of the disease in Kuwait. Methods: This is a retrospective study of cases identified over a period of 14 years (1985–1999). Three hundred forty-six patients were identified to have chronic ulcerative colitis. Ninety patients were interviewed for this study. Results: Chronic ulcerative colitis is being identified with increasing frequency. Our local incidence was 2.8 per 100,000 persons per year. The disease was seen in both sexes with equal frequency. It peaks at the third decade of life, with no second peak observed in the sixth decade. The disease was of mild to moderate severity in 93% of the cases. The distribution of the disease in the colon showed pancolitis in 45%, left-sided colitis in 14%, proctosigmoiditis in 21% and proctitis in 20%. Arthritis and arthralgia were the most frequent extraintestinal manifestation seen in 31%. Perianal disease, although rare in ulcerative colitis, was seen in 8%. Of interest is the fact that over 14 years of follow-up, none of our patients developed high-grade dysplasia or colorectal cancer. Four patients required total colectomy mainly due to failure of medical therapy. Conclusions: Chronic ulcerative colitis is occurring with increasing frequency similar to that seen in Western countries. The disease observed in our patient population was of mild to moderate severity, with fewer complications than reported in Western countries. It peaks in the third decade with no second peak. None of our patients developed high-grade dysplasia or colorectal carcinoma.
Prevalence of Low Back Pain among Physical Therapists in Kuwait
Authors: Shehab Dia , Al-Jarallah Khalid , Moussa Mohamed A.A. , Adham Nihad
Published: September 2003

Objective: To determine the life and point prevalence rates and study the characteristics of work-related and non-work-related low back pain (LBP) among physical therapists in Kuwait and its effect on their regular activities. Subjects and Methods: A specially designed self-administered questionnaire was distributed to 143 physical therapists in Kuwait. The questionnaire included demographic data, history and characteristics of LBP before and after working as a physical therapist, the effect of LBP on regular activities and current LBP. A visual analogue scale was used to score the intensity of the pain. Results: One hundred (70%) of the 143 physical therapists completed the questionnaire; mean age and standard deviation of the respondents were 35.9 ± 8.45 years. The lifetime prevalence of work-related LBP was 70% (61.8% in males and 74.2% in females) and the point (current) prevalence rate was 57% (31.6% in males and 68.4% in females). All the 100 therapists were college graduates who worked full-time and 82% were employed in general hospitals and rehabilitation centers. The most common areas of specialty were orthopedics (32%) and neurology (23%). Fifty percent reported that LBP affected their regular activities, 28.6% reported limitation due to pain and 11.4% changed their work settings because of LBP. The main site of pain was at low back and buttocks. Pain intensity was scored similarly among male and female physical therapists. Conclusion: Work-related and point prevalence rates of LBP among physical therapists in Kuwait are high and affect their daily activities, necessitating changes in work settings.
Efficacy of Chordal Cutting to Relieve Chronic Persistent Ischemic Mitral Regurgitation
Authors: Messas Emmanuel , Pouzet Bruno , Touchot Bernard , Guerrero J. Luis , Vlahakes Gus J. , Desnos Michel , Menasché Philippe , Hagège Albert , Levine Robert A.
Published: September 2003

Background—

Mitral regurgitation (MR) conveys adverse prognosis in ischemic heart disease. Leaflet closure is restricted by tethering to displaced papillary muscles, and is, therefore, incompletely treated by annular reduction. In an acute ischemic model, we reduced such MR by cutting a limited number of critically positioned chordae to the leaflet base that most restrict closure but are not required to prevent prolapse. Whether this is effective without prolapse, recurrent MR, or left ventricular (LV) failure in chronic persistent ischemic MR, despite greater LV remodeling, remains to be established. Therefore, we studied 7 sheep with chronic inferobasal infarcts known to produce progressive MR over 2 months. In all of those sheep, after a mean of 4.1 months, the 2 central basal (intermediate) chordae were cut at the chronic ischemic MR stage. 3-Dimensional echo quantified MR, LV function, and valve geometry. Five other sheep were followed for a mean of 7.8±1.2 months after inferobasal infarction with chordal cutting.

Results—

All 7 of the sheep with chronic ischemic MR (increased from 1.4±0.4 to 11.1±0.5 mL/beat, regurgitant fraction=39.0±4.2%,
P
<0.0001) showed anterior leaflet angulation at the basal chord insertion. Although end-systolic volume had doubled, cutting the 2 central basal chordae significantly decreased the MR to baseline (
P
<0.0001) without prolapse or decline in EF (41.1±1.5% to 42.6±1.6%,
P
=not significant [NS]). The five sheep with long-term follow-up showed no prolapse or MR, and no significant post-infarct decrease in LV ejection fraction (EF; 38.9±2.4% to 41.4±1.2%,
P
=NS).

Conclusion—

Cutting a minimum number of basal (intermediate) chordae can improve coaptation and reduce chronic persistent ischemic MR without impairing LVEF. No adverse effects were noted long-term after chordal cutting at the time of infarction.
Early Versus Delayed Revascularization in Patients With Ischemic Cardiomyopathy and Substantial Viability: Impact on Outcome
Authors: Bax Jeroen J. , Schinkel Arend F.L. , Boersma Eric , Rizzello Vittoria , Elhendy Abdou , Maat Alexander , Roelandt Jos R.T.C. , van der Wall Ernst E. , Poldermans Don
Published: September 2003

Background—

Patients with ischemic cardiomyopathy and viable myocardium may improve in function and prognosis following revascularization. Delayed revascularization may result in less favorable outcome, and therefore the impact of timing of revascularization on long-term outcome was evaluated.

Methods and Results—

Patients (n=85) with ischemic cardiomyopathy and substantial viability (≥25% of the left ventricle) on dobutamine stress echocardiography underwent surgical revascularization. Based on the waiting time for revascularization, patients were divided into 2 groups: early (≤1 month) and late (>1 month) revascularization. Left ventricular ejection fraction (LVEF) was assessed before and 9 to 12 months after revascularization; follow-up data were acquired up to 2 years after revascularization. Hence, 40 patients underwent early (20±12 days) and 45 late (85±47 days) revascularization. Baseline characteristics of the two groups were comparable. Preoperative deaths were 0 in the early and 2 in the late group. Patients with early revascularization remained shorter time in the intensive care unit (2.4±1.5 days versus 5.9±2.1 days for the late group,
P
<0.05). Low output syndrome was observed more frequently in the late group (8% versus 22%,
P
=0.06). On long-term follow-up, mortality (5% versus 20%,
P
<0.05) and re-hospitalization for heart failure (10% versus 24%, NS) were higher in the late group. LVEF improved from 28±9% to 40±12% (
P
<0.05) in the early group and remained unchanged in the late group (27±10% versus 25±7%, NS).

Conclusion—

Patients with ischemic cardiomyopathy and viable myocardium benefit from early revascularization (with improvement in LVEF and favorable prognosis), whereas delayed revascularization of these patients is associated with worse outcome.
The Role of the Social Sciences in Emerging Civil Society in Thailand
Authors: Vaddhanaphuti Chayan
Published: September 2003

This paper examines social development as a process and as a historically produced discourse before and during the crisis in Southeast Asia. Using the case of Thai social science in different historical periods — from distanced social science to socially engaged social science — to illustrate its relevance to social development, this paper argues that new modes of knowing is necessary to challenge, rethink, and reconstruct the role of social science based on situated knowledge and contextualised views expressed.
Looking Back on the Asian Crisis: The Question of Convergence
Authors: Robison Richard
Published: September 2003

The persistence of non-liberal regimes in Asia, even after the financial and economic crisis, raises questions about how social and economic regimes change and the sort of legal and political frameworks required by modern market capitalism. This paper looks at the issue of convergence and critically assesses claims that the apparent failure of market transformation results from poor policies, weak institutions, captured states and weak social capital. It is argued that the failures of convergence call into question the very assumptions that neo-liberal reform requires markets that are open, governments where public and private interest is separated and defined by law, and democratic political systems.
Crises as Opportunities to Consolidate Reforms: The 1997 Financial Crisis and Banking Policy Reform in Malaysia and the Philippines
Authors: Cook Malcolm
Published: September 2003

Looking at crisis responses in the Philippines and Malaysia, this paper will analyse how state-based banking policy elites in both states used the 1997–2000 crisis to radically accelerate pre-crisis policy directions that were opposed by local banking institutions and their peak associations. Drawing on empirical evidence and policy reform theory, the paper will detail how these elites used both their ability to define the nature of the 1997–2000 crisis and the appropriate responses, and their control of the executive to accelerate these directions and minimize the voice of local banking players. In the case of Malaysia, the banking policy direction to be analyzed will be banking sector consolidation, while for the Philippines it will be foreign entry and equity participation in the local banking sector. Moving away from the singular domestic focus of much policy reform literature, this paper will attempt to develop a two-level model for these crisis-driven policy accelerations. To do this, it will look at the use by these state elites of their relationships with the IMF and their banking policy obligations of the GATS as the rationale for acceleration and as the rationale for their overriding of local banking interests. This incorporation of external actors and changes to the international political economy should allow for a more nuanced and well-rounded understanding of these specific elements of the 1997–2000 crisis response, as well as the political economy of policy reform in general for both Malaysia and the Philippines.
Preparing for the Pox: A Theory of Smallpox in Bengal and Britain
Authors: Naraindas Harish
Published: September 2003

This essay is to be conceived in two parts. The first part is an exegesis of an eighteenth-century tract on the practice of smallpox inoculation in Bengal written by a Scottish medic. Cited repeatedly in the contemporary history and anthropology of smallpox in India, it has been invariably used to highlight the

technique

of inoculation in eighteenth-century India. Caught in disciplinary cleaving between anthropology and history, its original import has not been addressed. The exegesis in restoring the text to its intended import, argues that it offers a

theory

of smallpox, and in this theory the technique of inoculation is a moment in larger therapeutics. The latter-day privileging of this moment has resulted in seeing the nineteenth-century as a standoff between variolation (smallpox inoculation) and vaccination. The exegesis, however, recasts this as a passage from a therapeutics to a pure prophylactics that caccination represents. Having restored what I think is the central concern of the essay, I then begin to ask whether the essay is actually about the manner of inoculating for the smallpox in Bengal as Holwell says it is or is it actually about its practice in Britain. It is this very restoration, when we locate the essay in 18th century Britain, that allows us, in the latter part of the essay, to to see that not only is the theoretical articulation "induced" by his audience, but also every detail of the

description of the practice

, which has hitherto been seen as a description determined by his experience in India, is equally induced and

determined by his location in Britain

. While this could lead me to argue that Holwell's essay has nothing to do with India, I suggest that what the text effects, if not represents, is a kind of

translation

: one that is both possible and enabled by the fact that the kind of medical theory and practice that underlies disease and its cure is similar - not identical - in India and Britain.
Elevated Umbilical Cord Ghrelin Concentrations in Small for Gestational Age Neonates
Authors: Farquhar Juliet , Heiman Mark , Wong Alfred C. K. , Wach Richard , Chessex Philippe , Chanoine Jean-Pierre
Published: September 2003

Ghrelin has orexigenic effects. It is present in umbilical cord plasma in full-term neonates, raising the prospect that ghrelin plays a role in fetal and neonatal energy balance. We measured ghrelin in small (SGA), appropriate (AGA), and large (LGA) for gestational age neonates and evaluated whether ghrelin levels are modulated by neonatal insulin and glucose concentrations. Plasma concentrations of ghrelin, insulin, and glucose were measured in cord blood sampled at birth in 123 SGA, AGA, and LGA neonates (gestational age, 24–41 wk) born to mothers with and without diabetes. Ghrelin was detected in samples from all infants. Its concentration was 40% higher in SGA neonates (mean ± sd, 2436 ± 657 pg/ml) compared with AGA (1738 ± 380) and LGA (1723 ± 269) neonates. There was a positive correlation between ghrelin and gestational age in AGA/LGA (r = 0.23; P < 0.05) and a negative correlation in SGA (r = −0.67; P < 0.005) neonates. Therefore, the difference in ghrelin between SGA and AGA/LGA neonates decreases with advancing gestational age. Birth weight z-score, maternal hypertension, and glucose concentrations were significant determinants of ghrelin concentrations. In conclusion, SGA neonates present with higher umbilical cord ghrelin plasma concentrations than AGA/LGA neonates. Ghrelin may play a physiological role in fetal adaptation to intrauterine malnutrition.
Hydrostatic bearings with multiport viscous pumps
Authors: Arafa H. A. , Osman T. A.
Published: September 2003

An analysis of multirecess hydrostatic bearings with linear flow-pressure supply characteristics is presented. These characteristics can be obtained using either a constant supply pressure source with a laminar flow restrictor before each recess, or, as suggested in this paper, a multiport viscous pump. Analysis of the viscous pump-bearing system is made for odd numbers of recesses, and it is shown that a staggered or skip-one sequence of connection of the pump ports to the bearing recesses gives the least unbalanced reaction between the pump rotor/stator. The flow-pressure characteristics of viscous pumps with peripheral shrouded Rayleigh steps in a cylindrical configuration are derived and used to design a five-port pump to match a hydrostatic bearing. An experimental pump is designed, manufactured and tested, and the results obtained at one port show good agreement with the theoretically calculated values of pressure and flow. If this port is taken as representative of a pump, which is manufactured with higher accuracy, then the principle of having an effective multiport viscous pump is hereby validated. A simple means is suggested for making the bearing stiffness and load-carrying capacity insensitive to temperature/viscosity changes.
Total ozone observations prior to the IGY. I: A history
Authors: Brönnimann S. , Staehelin J. , Farmer S. F. G. , Cain J. C. , Svendby T. , Svenøe T.
Published: September 2003

Current data archives of total ozone measurements, with only few exceptions, provide data only since the International Geophysical Year (IGY, July 1957 to June 1958) when a global network was established. However, total ozone data from the period prior to the IGY could be useful to study the past variability of the stratosphere. For this purpose, we have systematically compiled information and data from approximately 60 total ozone measurement series prior to 1957. This paper provides an overview of the measurement principles and techniques, discusses the historical and scientific context of the observations and summarizes specific information for each series (location, time period of observation, instrument, responsible person, current state and availability of the data, references). In an accompanying paper the quality of 17 data series is critically assessed and some corrections are proposed. © Royal Meteorological Society, 2003. S. F. G. Farmer's contribution is Crown copyright
The impact of the cooling time‐scale on the subgrid moisture field during cloud formation through homogeneous cooling
Authors: Stiller Olaf
Published: September 2003

Cloud formation induced by homogeneous cooling has recently been found to substantially alter the moisture distribution. This study uses cloud‐resolving simulations of an idealized atmospheric layer to investigate the impact of the cooling time τ (i.e. of how fast the cooling is applied) on this process. The findings can be interpreted as an increased mixing (of air with different moisture content) for increasing τ. More specifically the mixing‐induced decrease of the moisture fluctuations and the corresponding decrease of the cloud water content are stronger for larger τ.

This enhanced mixing is explained by the atmosphere's fast degrees of freedom (related to buoyancy oscillations) whose influence is found to grow for increasing τ. Exploiting scale separation between the different time‐scales, the behaviour of the fast degrees of freedom is deduced from the system's energy budget where the energy of the fast degrees of freedom is produced by the slow cooling process. © Crown copyright, 2003. Royal Meteorological Society
Shallow cumulus convection: A validation of large‐eddy simulation against aircraft and Landsat observations
Authors: Neggers R. A. J. , Duynkerke P. G. , Rodts S. M. A.
Published: September 2003

Large‐eddy simulation (LES) results of shallow cumulus convection are directly evaluated against in‐cloud aircraft measurements, as made during the Small Cumulus Microphysics Study (SCMS). To this purpose an LES case is first constructed, based on available observations (during SCMS). Then the simulations are directly compared with the in‐cloud measurements by using conditionally sampled fields. An advantage of the SCMS dataset is the combination of a range of different surface measurements, in‐cloud measurements by an aircraft at many levels in the cloud layer, and the availability of high‐resolution Landsat images.

The results show that given the correct initial and boundary conditions the LES concept is capable of realistically predicting the bulk thermodynamic properties of temperature, moisture and liquid‐water content of the cumulus‐cloud ensemble as observed in SCMS. Furthermore, the vertical component of the in‐cloud turbulent kinetic energy and the cloud size distribution in LES were in agreement with the observations. These results support the credibility of cloud statistics as produced by LES in general, and encourage its use as a tool for testing hypotheses and developing parametrizations of shallow cumulus cloud processes.

Several hypotheses which make use of conditionally sampled fields were tested on the SCMS data. The magnitudes and the decrease with height of the bulk entrainment rate following from the SCMS data confirm the typical values of the order of magnitude of 10−3 m−1 as reported in several other recent LES studies. An alternative formulation of the lateral entrainment rate as a function of the liquid‐water content and the mean lapse rate agrees well with the original form based on the conserved variables. Applying an often‐used simplified equation for the cloud vertical velocity to the aircraft measurements results in a reasonably closed budget. Copyright © 2003 Royal Meteorological Society
Gastrin: an analytical review
Authors: Varro Andrea , Ardill Joy ES
Published: September 2003

The gastric hormone gastrin is produced in multiple forms that vary in their biological properties. In this analytical review, the strategies available for the assay of different gastrins in plasma are considered. Except for research purposes, it is seldom necessary or even desirable to employ assays that are specific for an individual molecular form of gastrin. Instead, routine clinical assays of plasma gastrin should ideally react equally with the sulphated and unsulphated forms of the COOH-terminally amidated peptides, the most important of which are peptides of 17 and 34 amino acid residues (i.e. G17 and G34), and should not react with the related hormone cholecystokinin. Methods appropriate for the use of such assays are reviewed. These assays are important in the diagnosis of gastrinoma. Although it is recognized that circulating concentrations of gastrin are elevated in other conditions, including chronic atrophic gastritis, Helicobacter pylori infection and long-term administration of proton pump inhibitors, it is not clear whether gastrin radioimmunoassay is important for the clinical management in these conditions.
National guidelines for analysis of cerebrospinal fluid for bilirubin in suspected subarachnoid haemorrhage
Authors:   UK National External Quality Assessment Scheme for Immunochemistry Working Group
Published: September 2003

It is crucially important to detect subarachnoid haemorrhage (SAH) in all patients in whom it has occurred in order to select patients for angiography and preventative surgery. A computed tomography (CT) scan is positive in up to 98% of patients with SAH presenting within 12h but is positive in only 50% of patients presenting within 1 week.

Cerebrospinal fluid (CSF) bilirubin spectrophotometry can be used to determine the need for angiography in those few CT-negative patients in whom clinical suspicion of a SAH remains high; it may remain positive for up to 2 weeks after the event. The lumbar puncture (LP) should only be performed >12h after the onset of presenting symptoms. Whenever possible, collect four sequential CSF specimens. Always ensure that the last CSF sample taken is sent for bilirubin analysis. Protect the CSF from light and avoid vacuum tube transport systems if possible.

Always use spectrophotometry in preference to visual inspection. All CSF specimens are precious and should be analysed no matter how they were transported, where necessary with appropriate notice of the caveats regarding oxyhaemoglobin. Centrifuge the specimen at >2000 rpm for 5 min as soon as possible after receipt in the laboratory and in any case within 1 h of collection. Store the supernatant at 4°C in the dark until analysis.

An increase in CSF bilirubin is the key finding which supports the occurrence of SAH, but it is not specific for this. In most positive cases bilirubin will occur with oxyhaemoglobin. Oxyhaemoglobin occurring on its own is difficult to interpret and may be increased as a result of in vitro haemolysis of red cells introduced into the CSF during lumbar puncture. This process is exacerbated by vacuum tube transport systems. Results should be interpreted in the light of other investigations (e.g. if scan shows bilirubin then measure serum bilirubin and CSF oxyhaemoglobin and protein) and other confounding variables such as the time elapsed from presentation to LP.
Innovative Reactive Power Saving in Wind-driven Grid-connected Induction Generators Using a Delta-star Stator Winding Part I: Performance Analysis of the Delta-Star Generator and Test Results
Authors: Kumaresan N. , Subbiah M.
Published: September 2003

An innovative delta-star three-phase winding, developed earlier for harmonic reduction in 3-phase induction motors, is applied for constant speed grid-connected induction generators. A method has been developed for the prediction of the performance of the generator with such an unconventional winding. It has been demonstrated that with a suitable switching arrangement, the proposed delta-star generator can result in increased real power delivered to the grid and reduced reactive power drawn from the grid, as compared to a fixed stator configuration. A suitable microcontroller-based switching-scheme has also been designed for changing the stator connection according to the wind speed. The facility for using the star mode of the generator while connecting it to the grid with much reduced inrush current is also illustrated.
Cystamine inhibits transglutaminase and caspase‐3 cleavage in glutamate‐exposed astroglial cells
Authors: Ientile R. , Campisi A. , Raciti G. , Caccamo D. , Currò M. , Cannavò G. , Li Volti G. , Macaione S. , Vanella A.
Published: September 2003

Although the precise role of transglutaminase in cell death is unknown, several findings demonstrate that tissue transglutaminase selectively accumulates in cells undergoing apoptosis both in vivo and in vitro. Calcium‐dependent transglutaminase reactions are also implicated in several neurodegenerative diseases, including alterations in the release of excitatory amino acids. One prevalent theme in cell damage induced by excitotoxic stimuli in different regions of the CNS is that apoptosis may be executed by intracellular caspase proteases. Furthermore, the presence of functional ion channel‐gated receptors in glial cells suggests that also astrocytes can be susceptible to glutamate's toxic effects. In this study, we demonstrated that prolonged exposure to glutamate (100 μM) of cultured astrocytes caused an increase in the expression of tissue transglutaminase (tTG). This effect was prevented by preincubation with GYKI 52466, an antagonist of AMPA/KA receptors. Glutamate exposure also promoted an increase in caspase‐3 compared with control cultures. Confocal laser microscopy analysis demonstrated the presence of activated caspase‐3 in the cytoplasm as well as in the nucleus. The inhibition of TG‐catalyzed reactions by cystamine (1 mM) blocked the activation pathway of caspase‐3, with an evident reduction of enzyme cleavage. These results suggest that glutamate increased both TG and caspase‐3 in astroglial cells early in the excitotoxin‐induced events. © 2003 Wiley‐Liss, Inc.
‘Ultimate’ robustness in meshing an arbitrary polyhedron
Authors: George P. L. , Borouchaki H. , Saltel E.
Published: September 2003

Given a boundary surface mesh (a set of triangular facets) of a polyhedron, the problem of deciding whether or not a triangulation exists is reported to be NP‐hard. In this paper, an algorithm to triangulate a general polyhedron is presented which makes use of a classical Delaunay triangulation algorithm, a phase for recovering the missing boundary facets by means of facet partitioning, and a final phase that makes it possible to remove the additional points defined in the previous step. Following this phase, the resulting mesh conforms to the given boundary surface mesh. The proposed method results in a discussion of theoretical interest about existence and complexity issues. In practice, however, the method should provide what we call ‘ultimate’ robustness in mesh generation methods. Copyright © 2003 John Wiley & Sons, Ltd.
Enhanced gene silencing by the application of multiple specific small interfering RNAs
Authors: Ji Jingmin , Wernli Marion , Klimkait Thomas , Erb Peter
Published: September 2003

Small interfering RNA duplexes (siRNA) induce gene silencing in various eukaryotic cells, although usually in an incomplete manner. Using chemically synthesized siRNAs targeting the HIV‐1 co‐receptor CXCR4 or the apoptosis‐inducing Fas‐ligand (FasL), co‐transfection of cells with two or more siRNA duplexes targeting different sites on the same mRNA resulted in an enhanced gene silencing compared with each single siRNA. This was shown in the down‐regulation of protein and mRNA expression, and functionally in the inhibition of CXCR4‐mediated HIV infection and of FasL‐mediated cell apoptosis. Transfection efficiency determined for the FasL‐specific siRNAs was dose‐dependent and varied among the siRNAs tested, but was not the main reason for the enhanced gene silencing.
Two mammalian glucosamine‐6‐phosphate deaminases: a structural and genetic study
Authors: Arreola Rodrigo , Valderrama Brenda , Morante Maria L , Horjales Eduardo
Published: September 2003

Glucosamine‐6‐phosphate deaminase (EC 3.5.99.6) is an allosteric enzyme that catalyzes the reversible conversion of D‐glucosamine‐6‐phosphate into D‐fructose‐6‐phosphate and ammonium. Here we describe the existence of two mammalian glucosamine‐6‐phosphate deaminase enzymes. We present the crystallographic structure of one of them, the long human glucosamine‐6‐phosphate deaminase, at 1.75 Å resolution. Crystals belong to the space group P212121 and present a whole hexamer in the asymmetric unit. The active‐site lid (residues 162–182) presented significant structural differences among monomers. Interestingly the region with the largest differences, when compared with the Escherichia coli homologue, was found to be close to the active site. These structural differences can be related to the kinetic and allosteric properties of both mammalian enzymes.
Identification and characterisation of a new human glucose‐6‐phosphatase isoform
Authors: Guionie Olivier , Clottes Eric , Stafford Kirsten , Burchell Ann
Published: September 2003

The liver endoplasmic reticulum glucose‐6‐phosphatase catalytic subunit (G6PC1) catalyses glucose 6‐phosphate hydrolysis during gluconeogenesis and glycogenolysis. The highest glucose‐6‐phosphatase activities are found in the liver and the kidney; there have been many reports of glucose 6‐phosphate hydrolysis in other tissues. We cloned a new G6Pase isoform (G6PC3) from human brain encoded by a six‐exon gene (chromosome 17q21). G6PC3 protein was able to hydrolyse glucose 6‐phosphate in transfected Chinese hamster ovary cells. The optimal pH for glucose 6‐phosphate hydrolysis was lower and the K
m higher relative to G6PC1. G6PC3 preferentially hydrolyzed other substrates including pNPP and 2‐deoxy‐glucose‐6‐phosphate compared to the liver enzyme.
Enhanced in vivo delivery of antisense oligonucleotides to restore dystrophin expression in adult mdx mouse muscle
Authors: Wells K.E. , Fletcher S. , Mann C.J. , Wilton S.D. , Wells D.J.
Published: September 2003

The use of antisense oligonucleotides (AOs) to induce exon skipping leading to generation of an in‐frame dystrophin protein product could be of benefit in around 70% of Duchenne muscular dystrophy patients. We describe the use of hyaluronidase enhanced electrotransfer to deliver uncomplexed 2′‐O‐methyl modified phosphorothioate AO to adult dystrophic mouse muscle, resulting in dystrophin expression in 20–30% of fibres in tibialis anterior muscle after a single injection. Although expression was transient, many of the corrected fibres initially showed levels of dystrophin expression well above the 20% of endogenous previously shown to be necessary for phenotypic correction of the dystrophic phenotype.
Adhesion forces measured between a calcium blocker drug and its receptor in living cells using atomic force microscope
Authors: de Souza Pereira Ricardo , da Silva Maria Ivonete Nogueira , Cotta Mônica Alonso
Published: September 2003

The adhesion force between the tip of an atomic force microscope cantilever derivatized with nimodipine (a calcium blocker, from the dihydropyridine class, currently used in clinical medicine for hypertension) and living cells of Saccharomyces cerevisiae (unicellular eukaryotes which portray ultrastructural features characteristic of higher eukaryotic cells) was measured. This methodology allowed us to locate (and visualize) pores on the cell surface which may be responsible for calcium transportation in the living cells. The interaction of the cantilever derivatized with the calcium blocker and a pore, which can be a calcium channel, is more intense than a non‐derivatized cantilever and the pore. Outside the pore (on the rest of cell surface), a derivatized or a non‐derivatized cantilever has the same pattern of adhesion force. The information obtained with this method is very important for the design of new, more potent and less toxic drugs for pharmacological use.
A transient tobacco expression system coupled to MALDI‐TOF‐MS allows validation of the impact of differential targeting on structure and activity of a recombinant therapeutic glycoprotein produced in plants
Authors: Mokrzycki-Issartel Nathalie , Bouchon Bernadette , Farrer Sibille , Berland Patricia , Laparra Hélène , Madelmont Jean-Claude , Theisen Manfred
Published: September 2003

Tobacco‐based transient expression was employed to elucidate the impact of differential targeting to subcellular compartments on activity and quality of gastric lipase as a model for the production of recombinant glycoproteins in plants. Overall N‐linked glycan structures of recombinant lipase were analyzed and for the first time sugar structures of its four individual N‐glycosylation sites were determined in situ by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) on a trypsin digest without isolation or deglycosylation of the peptides. Three glycosylation sites contain both complex‐type N‐glycans and high‐mannose‐type structures, the fourth is exclusively linked to high‐mannose glycans. Although the overall pattern of glycan structures is influenced by the targeting, our results show that the type of glycans found linked to a given Asn residue is largely influenced by the physico‐chemical environment of the site. The transient tobacco system combined with MALDI‐TOF‐MS appears to be a useful tool for the evaluation of glycoprotein production in plants.
Cationic lipids and cationic ligands induce DNA helix denaturation: detection of single stranded regions by KMnO4 probing
Authors: Prasad T.K , Gopal Vijaya , Rao N.Madhusudhana
Published: September 2003

Cationic lipids and cationic polymers are widely used in gene delivery. Using 1,2‐dioleoyl‐3‐trimethylammonium‐propane (DOTAP) as a cationic lipid, we have investigated the stability of the DNA in DOTAP:DNA complexes by probing with potassium permanganate (KMnO4). Interestingly, thymidines followed by a purine showed higher susceptibility to cationic ligand‐mediated melting. Similar studies performed with other water‐soluble cationic ligands such as polylysine, protamine sulfate and polyethyleneimine also demonstrated melting of the DNA but with variations. Small cations such as spermine and spermidine and a cationic detergent, cetyl trimethylammonium bromide, also rendered the DNA susceptible to modification by KMnO4. The data presented here provide direct proof for melting of DNA upon interaction with cationic lipids. Structural changes subsequent to binding of cationic lipids/ligands to DNA may lead to instability and formation of DNA bubbles in double‐stranded DNA.
Platelet‐derived growth factor induces p21/WAF1 promoter in vascular smooth muscle cells via activation of an Sp1 site
Authors: Moon Sung-Kwon , Jung Sun-Young , Choi Yung-Hyun , Lee Young-Choon , Kim Cheorl-Ho
Published: September 2003

Many studies suggested that cyclin‐dependent kinase inhibitor (CDKI) p21 acts as a universal inhibitor of cyclin/CDK catalytic activity. This protein has also been shown to be a component of active cyclin/CDK complexes. In addition, it has recently been suggested that p21 serves as an assembly factor in platelet‐derived growth factor (PDGF)‐stimulated vascular smooth muscle cells (VSMC). However, little is known concerning the molecular mechanisms by which PDGF induces p21 gene expression in VSMC. In this report we demonstrate that PDGF induces the p21 expression at both the mRNA and protein levels. This increase in p21 gene expression was due to activation of the p21 promoter by PDGF. Through both deletion and mutation analysis of the p21 promoter, we defined a 10‐bp sequence that is required for the activation of the p21 promoter by PDGF. In addition, gel shift and supershift assays demonstrated that this PDGF‐responsive element binds specifically to the transcription factor Sp1. These results demonstrate that Sp1 mediates PDGF‐induced p21 gene expression in VSMC. Moreover, immunoblot and immonoprecipitation analysis showed that the level of hyperphosphorylated retinoblastoma protein (Rb) is increased and the protein is physically associated with Sp1 in PDGF‐treated cells, indicating that phosphorylated Rb may play a role in regulating Sp1 to activate p21 expression.
Surgical Treatment of Gunshot Injuries to the Mandible
Authors: Newlands Shawn D. , Samudrala Sreedhar , Katzenmeyer W. Kevin
Published: September 2003

OBJECTIVES

Our goal was to review and identify risk factors for complications from treatment of mandible fractures due to gunshot wounds.

STUDY DESIGN AND SETTING

We conducted a retrospective review of treatment outcomes in 90 patients with gunshot wounds to the mandible treated over a 10‐year period at 2 tertiary care centers.

RESULTS

Our series of 90 patients with mandibular injuries due to gunshot wounds included 68 patients who underwent surgical procedures on the mandible. There were 14 complications in this group. Complications were more common in patients whose mandibles were rigidly fixated; however, these patients' injuries were more severe. Complications were significantly increased in patients who lost a segment of mandible in the injury.

CONCLUSIONS

Complications were related to severity of injury and independent of treatment modality.

SIGNIFICANCE

The complication rate for patients with gunshot injuries can be very high, particularly if bone is missing. Stabilization of remaining mandibular segments with potentially multiple subsequent reconstructive procedures is often required to restore mandibular continuity in these patients.