bluuebunny/crossref_metadata_2025_split huggingface dataset:
RISK FACTORS FOR POST‐APPENDICECTOMY INTRA‐ABDOMINAL ABSCESS
Authors: Reid Richard I. , Dobbs Bruce R. , Frizelle Frank A. 
Published: July 2002

Background: Appendicectomy is a common emergency operation, after which major complications are uncommon, however when they do occur they are a major cause of concern to patient and surgeon. This study aims to determine the incidence and risk factors for post‐appendicectomy intra‐abdominal abscess formation. Method: A retrospective review was undertaken of all appendicectomies undertaken in Christchurch Hospital between 1 January and 31 December 1995. Appendicectomies were identified from a database of histology. The patients’ notes were reviewed and the surgical approach, histological diagnosis and postoperative complications identified. Results: A total of 417 appendicectomies was identified of which 331 were open, 66 laparoscopic, and 20 undertaken at laparotomy. Mean day stays for each group were 4.4, 4.2 and 11.5 days, respectively. The percentages of patients with acute appendicitis in each group were 87, 58 and 35%. Histologically the appendix was inflamed in 80% (334) of patients (acute 232, chronic 15, perforated 56 and gangrenous 24). There were six postoperative intra‐abdominal abscesses (1.4%), all occurring in the open appendicectomy group when the histology was either perforated or gangrenous appendicitis (P < 0.001). There were no cases of postoperative abscess formation following laparoscopic appendicectomy. All cases of postoperative intra‐abdominal abscess were associated with perforated and/or gangrenous appendicitis (P < 0.001). The incidence of intra‐abdominal abscesses was 7.5% with a perforated and/or gangrenous appendix. There were two cases of iatrogenic perforation following laparoscopic appendicectomy. Conclusion: The incidence of intra‐abdominal abscess is 1.4% of all appendicectomies. The only identified risk factor for development of post‐appendicectomy intra‐abdominal abscess was the underlying pathology of gangrenous or perforated appendicitis.
Maximal post‐prandial triglyceride increase reflects post‐prandial hypertriglyceridaemia and is associated with the insulin resistance syndrome
Authors: Karamanos B. G. , Thanopoulou A. C. , Roussi‐Penesi D. P. 
Published: July 2002

SUMMARY Aims  To assess the value of maximal post‐prandial triglyceride increase after a high fat, low carbohydrate (CHO) test meal, as index of post‐prandial hypertriglyceridaemia and its relation with insulin resistance.Methods  Fifty non‐diabetic subjects, 22 male and 28 female, aged 52.1 ± 4.5 and 56.9 ± 3.8 years, were studied. Glucose, insulin and triglycerides were measured fasting and 1, 2, 3 and 4 h after a meal consisting of 40 g fat, 19 g protein and 10 g CHO. Insulin resistance was calculated according to the HOMA model.Results  The maximal triglyceride increment occurred during the 4th hour. Its absolute value (Δ‐TG) and the per cent increase over the fasting value (PTI), were considered appropriate for the evaluation of the post‐prandial triglyceride response. Both Δ‐TG and PTI were strongly correlated with triglycerides incremental area in males and females, r = 0.797 and r = 0.700, P < 0.01 and r = 0.805 and r = 0.774, P < 0.001, respectively, and thus they can be used as indices of the post‐prandial triglyceride response. No correlation was found between fasting triglyceride and triglyceride incremental area or Δ‐TG. Thus, post‐prandial hypertriglyceridaemia can occur irrespectively of the fasting triglyceride concentrations. A weak correlation was found between PTI and insulin resistance in females, r = 0.384, P < 0.05, but not in males, r = 0.224, P > 0.05. However further analysis by quartiles of PTI showed similar insulin resistance levels in the first three quartiles and a significant increase in the 4th, both for males and females, 4th vs. 3rd quartile 7.4 ± 3.6 vs. 2.2 ± 0.7 and 6.4 ± 2.4 vs. 2.2 ± 0.6, respectively. The 4th quartile corresponds to a PTI ≥ 80%.Conclusions  PTI after the high fat, low CHO test meal used, consistently reflects post‐prandial hypertriglyceridaemia, is easily measured and it is not predicted by fasting triglycerides. A PTI ≥ 80% is associated with a significant increase of insulin resistance, and might therefore be considered the cut‐off point for an abnormal post‐prandial hypertriglyceridaemic response, at least in relation with insulin resistance. Such response could be added to the abnormalities of the insulin resistance syndrome, as an independent parameter.
An interrupted field time-of-flight (IFTOF) technique in transient photoconductivity measurements
Authors: Kasap S. O. , Polischuk B. , Dodds D. 
Published: July 2002

An interrupted field time-of-flight (IFTOF) technique that enables displacement-current-free measurement of the photocurrent in the conventional transient photoconductivity experiment is described and implemented. During the drift of the photoinjected charge carriers across the sample, the applied field is removed at time T1 and reapplied at time T2=T1+ti, where ti is the interruption time. During the interruption period ti, the charge carriers interact with the deep traps so that the recovered photocurrent when the field is reapplied at T2 = T1 + ti indicates the concentration of carriers remaining in the transport band. Although the IFTOF technique has a number of distinct advantages for studying charge trapping and release processes in high-resistivity solids, it has generally not been adopted as a convenient experiment since the sample capacitance results in large displacement currents at switching.
The present paper describes a Schering-type bridge network that is excited by a switchable floating high-voltage supply. Recently available high-voltage complementary TMOS transistors were used to switch voltages as high as 500 V. Trigger signals to initiate the various IFTOF events were simply and economically generated from TTL logic gates and IC timers while the required time delays were obtained via clocked digital countdown techniques. The IFTOF method was successfully applied to the examination of hole trapping processes in chlorinated a-Se:0.3%As xeroradiographic-type films for which the conventional TOF measurement indicated essentially trap-free photocurrent. Using the IFTOF technique, it is shown that over a time scale far exceeding the conventional TOF transit time, the photoinjected hole concentration under low field conditions decays almost exponentially with a well-defined trapping time τ. Furthermore, by interrupting the electric field while the photoinjected charge packet is at different locations in the film, it is shown that the IFTOF technique may be used to examine the dependence of the trapping time on the distance into the film. IFTOF is therefore a valuable technique for studying trapping inhomogeneities in amorphous semiconductor films. It is expected that the simple displacement-current-free IFTOF technique described in this paper, with further improvements, may be applied to study charge carrier trapping and release kinetics in a wide variety of high-resistivity solids.
Force calculations with three-dimensional scalar potential based finite-element programs (abstract)
Authors: Lowther D. A. , Forghani B. 
Published: July 2002

In the design of many electromagnetomechanical devices one of the prime parameters of interest is the mechanical force of torque produced by the device. The generated forces are of interest in two forms. The first is the distribution, which might be used to indicate a particular loading on some part of the structure; the second is a global value which appears at the mechanical interface. It is with the calculation of the latter that this paper is concerned. Much has been published concerning force calculations in two-dimensional solutions and it is the intention of this paper to discuss the extension of these methods to three-dimensional, scalar potential based analyses and to give examples of computed and measured results on several different devices.
In general, the methods that are used in two dimensions are applicable in three dimensions. These are ususally classified as single- and multiple-solution techniques. Into the first category fall Maxwell stresses and the Coulomb implementation of virtual work; into the second falls the classical virtual work approach. The Maxwell stress approach requires a surface integral of a product of flux density (B) components. In two dimensions this is a relatively simple task; it reduces to defining a line in the plane and computing B as the differential of A (the vector potential). In three dimensions, the definition of a surface may not be simple and, if a scalar potential is used for the solution, the computation of flux density components is far from trivial. When these requirements are compared with the classical virtual work approach, the reduction in computing effort by using a single-solution technique many not seem so significant. A second factor influencing the use of a multiple-solution approach is fundamental to the finite-element method; in general, the method produces accurate values for global quantities such as coenergy, with coarser discretizations than those required for local accuracy. Single-solution methods tend to require high-accuracy local fields and thus require considerably more computer effort per solution. On problems ranging from a disk drive actuator to a permanent magnet generator accuracies within 3% of measured have been computed with virtual work. The equivalent two-dimensional solutions did not do better than 10%.
Pressure isotherms, phase transition, instability, and structure of tethered polymers in good, Θ, and poor solvents
Authors: Carignano M. A. , Szleifer I. 
Published: July 2002

The conformational and thermodynamic behavior of chain molecules tethered to a planar surface are studied for a variety of solvent qualities with a recently developed single-chain mean-field theory. The lateral pressure isotherms calculated from the theory for chains of n=50 segments show very good quantitative agreement with the recent molecular dynamics simulations of Grest, without the use of any adjustable parameter, for good and Θ solvents. The behavior of the pressure isotherms is analyzed in terms of a virial expansion and it is shown that the regimes where there is scaling of the pressure with surface coverage σ are very narrow for this chain length. Moreover, comparisons with analytical self-consistent field (SCF) theory show good agreement only when the parabolic density profile is used in the full virial equation. In the bad solvent regime the pressure isotherms for grafted chains show negative values of the pressure and also a negative compressibility for some range of surface coverages for temperatures below the Θ temperature. This indicates the possibility of microphase separation in this regime of temperature and surface coverages.
For chains with translational degrees of freedom there is a first-order phase separation at temperatures below the Θ temperature into a very dilute and more concentrated polymer phase. From results of two different chain lengths it seems that there is a universal coexistence phase diagram in the scaling variables n0.5(T/Θ−1) vs nσ. In the bad solvent regime it is found that the chains are highly collapsed for very low surface coverage. As the surface coverage is increased the chains tend to stretch laterally in order to gain as much contact as possible with the other polymer chains. This is in contrast to the good solvent regime where the chains always stretch perpendicular to the surface in order to avoid as much contact as possible with the other polymer chains. In the intermediate surface coverage regime it is found that the density profiles look parabolic-like for good solvents becoming more steplike as the quality of the solvent becomes poorer, in agreement with recent neutron scattering experiments. For very high surface coverages the density profiles in the good solvent regime also look steplike.
Thermodynamic and stochastic theory of nonequilibrium systems: Fluctuation probabilities and excess work
Authors: Peng Bo , Hunt Katharine L. C. , Hunt Paul M. , Suárez Alberto , Ross John 
Published: July 2002

For a nonequilibrium system described at the mesoscopic level by the master equation, we prove that the probability of fluctuations about a steady state is governed by a thermodynamic function, the ‘‘excess work.’’ The theory applies to systems with one or more nonequilibrium steady states, for reactions in a compartment that contains intermediates Xj of variable concentration, along with a reactant A and product B whose concentrations are held constant by connection of the reaction chamber to external reservoirs. We use a known relation between the stationary solution Ps(X) of the master equation and an underlying stochastic Hamiltonian H: to logarithmic accuracy, the potential that gives Ps(X) is the stochastic action S evaluated along fluctuational trajectories, obtained by solving Hamilton’s equations of motion starting at a steady state. We prove that the differential action dS equals a differential excess work dφ0, and show that dφ0 can be measured experimentally in terms of total free energy changes for the reaction compartment and the reservoirs. Thus we connect the probability of concentration fluctuations in an open reaction compartment to thermodynamic functions for the entire closed system containing the compartment. The excess work dφ0 is the difference between the total free energy change for a specified change in the quantities of A, X, Y, and B in the state of interest, and the free energy change for the same changes in species numbers, imposed on the same system in a reference state (A,X0,Y0,B).
The reference-state concentration for species Xj is derived from the momentum pj canonically conjugate to Xj along the fluctuational trajectory. For systems with linear rate laws, the reference state (A,X0,Y0,B) is the steady state, and φ0 is equivalent to the deterministic excess work φdet* introduced in our previous work. For nonlinear systems, (A,X0,Y0,B) differs from the deterministic reference state (A,X*,Y*,B) in general, and φ0≠φdet*. If the species numbers change by ±1 or 0 in each elementary step and if the overall reaction is a conversion A→X→Y→B, the reference state (A,X0,Y0,B) is the steady state of a corresponding linear system, identified in this work. In each case, dφ0 is an exact differential. Along the fluctuational trajectory away from the steady state, dφ0≳0. Along the deterministic kinetic trajectory, dφ0≤0, and φ0 is a Liapunov function. For two-variable systems linearized about a steady state, we establish a separate analytic relation between Ps(X), φdet*, and a scaled temperature T*.
Generalized Green’s functions and spectral densities in the complex energy plane
Authors: Engdahl Erik , Brändas Erkki , Rittby Magnus , Elander Nils 
Published: July 2002

The Titchmarsh–Weyl theory is applied to the Schrödinger equation in the case when the asymptotic form of the solution is not known. It is assumed that the potential belongs to the Weyl’s limit-point classification. A rigorous analytical continuation of the Green’s function, obtained from the solution regular at the origin and the square integrable Weyl’s solution (regular at infinity), to the ‘‘unphysical’’ Riemann energy sheet is carried out. It is demonstrated how the Green’s function can be uniquely constructed from the Titchmarsh–Weyl m-function and its Nevanlinna representation. The behavior of the m-function in the neighborhood of poles is investigated. The m-function is decomposed in a, so called, generalized real part (Reg) and a generalized imaginary part (Img). Reg(m) is found to have a significant argument change upon pole passages. Img(m) is found to be a generalized spectral density. From the generalized spectral density, a spectral resolution of the differential operator and its resolvent is derived. In the expansion contributions are obtained from bound states, resonance states (Gamow states), and the ‘‘deformed continuum’’ given by the generalized spectral density.
The present expansion theorem is applicable to the general partial differential operator via a decomposition into partial waves. The numerical procedure involves all quantum numbers l and m, but for convenience, and with the inverse problem in mind, this study is focused on the case when the rotational quantum number equals zero. The theory is tested numerically and analyzed for an analytic model potential exhibiting a barrier and decreasing exponentially at infinity. The potential is Weyl’s limit point at infinity and allows for an analytical continuation into a sector in the complex plane. An attractive feature of the generalized spectral density of the present potential is that the poles close to the real axis seem to exhaust or deflate the above-mentioned density inside the pole string. Outside this string the density rapidly approaches that of a free particle. This information is used to derive an approximate representation of the m-function in terms of poles and residues as well as free-particle background. In order to display the features mentioned above, the present study is accompanied with several plots of analytically continued quantities related to the Green’s function.
Kinetic description of harmonic instabilities in a planar wiggler free-electron laser
Authors: Davidson Ronald C. 
Published: July 2002

The linearized Vlasov–Maxwell equations are used to investigate harmonic stability properties for a planar wiggler free-electron laser (FEL). The analysis is carried out in the Compton regime for a tenuous electron beam propagating in the z direction through the constant-amplitude planar wiggler magnetic field B0=−Bw  cos k0zêx. Transverse spatial variations are neglected (∂/∂x =0=∂/∂y), and the case of an FEL oscillator (temporal growth) is considered. Assuming ultrarelativistic electrons and κ2=a2w/(γ20−1) ≪1, where a2w =e2B2w /m2c4k20 and γ0mc2 is the electron energy, the kinetic dispersion relation is derived in the diagonal approximation for perturbations about general beam equilibrium distribution function G+0(γ0). Because of the wiggler modulation of the axial electron orbits, strong wave–particle interaction can occur for ω≊[k+k0(1+2l)] βFc, where βFc is the axial velocity, ω and k are the wave oscillation frequency and wavenumber, respectively, and l=0, 1, 2, . . . are harmonic numbers corresponding to an upshift in frequency. The strength of the lth harmonic wave–particle coupling is proportional to Kl(b1) =[Jl (b1)−Jl+1 (b1)]2, where b1=(k/8k0)κ2. Assuming that G+0(γ0) is strongly peaked around γ0=γ̂≫1, detailed lth harmonic stability properties are investigated for (a) strong FEL instability corresponding to monoenergetic electrons (Δγ=0), and (b) weak resonant FEL instability corresponding to a sufficiently large energy spread that ‖Im ω/[k+k0(1+2l)] Δvz ‖≪1.
For monoenergetic electrons the characteristic maximum growth rate scales as [Kl (b̂1)(1+2l)]1/3, which exhibits a relatively weak dependence on harmonic number l. Here, b̂1= 1/2 [a2w/(2+a2w)] (1+2l). On the other hand, for weak resonant FEL instability, the growth rate scales as Kl (b̂1)/(1+2l), which decreases rapidly for harmonic numbers l≥1.
Factors associated with continued smoking during pregnancy: analysis of socio‐demographic, pregnancy and smoking‐related factors
Authors: PENN G. , OWEN L. 
Published: July 2002

AbstractThis study investigated the characteristics associated with smoking during pregnancy. A total of 7836 pregnant women were surveyed between 1992 and 1999 in England. Of these 27% were smoking during pregnancy. Pregnant women were more likely to smoke if they were less educated, living in rented accommodation, in unskilled manual or unemployed groups, and single or had a partner who smokes. Analysed by logistic regression, whether or not a pregnant women has a partner and, if so, his smoking status, was by far the biggest predictor of the pregnant woman's current smoking status. Thus, compared with women with partners who never smoke, the odds ratio (OR) of smoking during pregnancy for women with a partner who smokes was 2.3 (1.9–2.7) while those with no partner had an OR of 4.8 (3.8–6.0). For women exposed to passive smoke at home or at work the OR was 2.5 (2.1–3.0). Housing tenure was the most important socio‐demographic predictor. Thus pregnant women living in rented council housing were nearly twice as likely (OR 1.93;1.63–2.29) as those buying their own home to be current smokers. The number of women who continued to smoke during pregnancy increased 10‐fold from the least to the most deprived group. These findings highlight the importance of tobacco control strategies that address pregnant women's life circumstances and broader inequalities as well as those that focus on individual smoking behaviour.
Daip1, a Dictyostelium Homologue of the Yeast Actin-Interacting Protein 1, Is Involved in Endocytosis, Cytokinesis, and Motility
Authors: Konzok Angelika , Weber Igor , Simmeth Evelyn , Hacker Ulrike , Maniak Markus , Müller-Taubenberger Annette 
Published: July 2002

The 64-kD protein DAip1 from Dictyostelium contains nine WD40-repeats and is homologous to the actin-interacting protein 1, Aip1p, from Saccharomyces cerevisiae, and to related proteins from Caenorhabditis, Physarum, and higher eukaryotes.
We show that DAip1 is localized to dynamic regions of the cell cortex that are enriched in filamentous actin: phagocytic cups, macropinosomes, lamellipodia, and other pseudopodia. In cells expressing green fluorescent protein (GFP)-tagged DAip1, the protein rapidly redistributes into newly formed cortical protrusions.
Functions of DAip1 in vivo were assessed using null mutants generated by gene replacement, and by overexpressing DAip1. DAip1-null cells are impaired in growth and their rates of fluid-phase uptake, phagocytosis, and movement are reduced in comparison to wild-type rates. Cytokinesis is prolonged in DAip1-null cells and they tend to become multinucleate. On the basis of similar results obtained by DAip1 overexpression and effects of latrunculin-A treatment, we propose a function for DAip1 in the control of actin depolymerization in vivo, probably through interaction with cofilin. Our data suggest that DAip1 plays an important regulatory role in the rapid remodeling of the cortical actin meshwork.
A posteriori error estimate for the mixed finite element method
Authors: Carstensen Carsten 
Published: July 2002

A computable error bound for mixed finite element methods is established in the model case of the Poisson–problem to control the error in the H(div,

Ω
\Omega

)

×

L
2

(
Ω
)

\times L^2(\Omega )

–norm. The reliable and efficient a posteriori error estimate applies, e.g., to Raviart–Thomas, Brezzi-Douglas-Marini, and Brezzi-Douglas-Fortin-Marini elements.
Locating probable genes using Fourier transform approach
Authors: Issac Biju , Singh Harpreet , Kaur Harpreet , Raghava G. P. S. 
Published: July 2002

Abstract
Summary: FTG is a web server for analyzing nucleotide sequences to predict the genes using Fourier transform techniques. This server implements the existing Fourier transform algorithms for gene prediction and allows the rapid visualization of analysis by output in GIF format.
Availability: The server is available at http://www.imtech.res.in/raghava/ftg/
Contact: raghava@imtech.res.in
Supplementary information: http://www.imtech.res.in/raghava/ftg/help/supl.html
* To whom correspondence should be addressed.