bluuebunny/crossref_metadata_2025 huggingface dataset:
Exchange bias and the origin of magnetism in Mn-doped ZnO tetrapods
Authors: Zheng R. K. , Liu H. , Zhang X. X. , Roy V. A. L. , Djurišić A. B.
Published: September 2004

Wurtzite-type ZnO tetrapod nanostructures were prepared by evaporating Zn metal under humid argon flow. After the fabrication, Mn was doped into ZnO nanostructures by diffusion at 600°C. The average concentration of Mn was determined to be 8.4mol% by x-ray fluorescence. X-ray diffraction patterns obtained from the doped and undoped samples are almost the same. High-resolution transmission electron microscopy observations reveal the existence of surface layers. Magnetic measurements show that the sample has a very large coercivity HC=5500Oe at 5.5K and a Curie temperature TC=43K, which may suggest that ferrimagnetic (Zn,Mn)Mn2O4 exists at the surface. Exchange bias is clearly observed below 22K. Exchange bias is attributed to the exchange interaction between ferrimagnetic (Zn,Mn)Mn2O4 and spin-glass-like (or antiferromagnetic) phase in manganese oxides.
Multiexcitonic two-state lasing in a CdSe nanocrystal laser
Authors: Chan Y. , Caruge J.-Michel , Snee P. T. , Bawendi M. G.
Published: September 2004

We report simultaneous amplified spontaneous emission from two different multiexcitonic transitions −1Se–1S3∕2 and 1Pe–1P3∕2− of colloidal CdSe nanocrystals (NCs) stabilized in high volume fraction in titania matrices. Two-state lasing from both multiexcitonic transitions is achieved in a surface-emitting distributed feedback CdSe NC laser. Variable stripe length measurements show that the gain from the 1Pe–1P3∕2 transition is approximately twice that of the −1Se–1S3∕2 transition for 4.2nm radius CdSe∕ZnS core-shell NCs.
Microscopic magnetic squeezer
Authors: Helseth L. E. , Fischer T. M. , Hansen R. W. , Johansen T. H.
Published: September 2004

A microscopic magnetic squeezer based on two magnetic domain walls moving along a one-dimensional potential well generated by a stress line in ferrite garnet films is demonstrated. The squeezer can operate on magnetic objects of size 1–200μm and exert compressive forces up to 10pN. The squeezer operation, i.e., the relative motion of the two domain walls, is well controlled by a small external magnetic field modulation. The squeezer has potential applications in microfluidics and also as sensitive pressure gauges for microbiological systems.
On the fragility of Nb-Ni-based and Zr-based bulk metallic glasses
Authors: Shadowspeaker L. , Busch R.
Published: September 2004

The heating rate dependencies of the glass transition temperature of the Ni65Nb35, Ni60Nb35Sn5, Ni59.35Nb34.45Sn6.2, Ni60(Nb40Ta60)34Sn6, and Ni57Fe3Nb35Sn5 metallic glass-forming alloys were investigated with a differential scanning calorimeter (DSC). The relaxation time for each DSC experiment was plotted versus inverse temperature, and a Vogel-Fulcher-Tamman (VFT)-type relation was fitted to the data. The fragilities of the alloys were characterized with the fragility parameter, D*, and the VFT temperature, T0, which are the fit parameters from the VFT relation. It was found that for the binary alloy D*=6.2, for the ternary alloys D*=11.0, and that for the quaternary alloys D* was between 16.4 and 19.0. These D* increase monotonically as the number of components in the alloy is increased. It was also found that the fragilities of Zr-based alloys show a similar trend.
Spin filtering through a double-bend structure
Authors: Shi Q. W. , Zhou J. , Wu M. W.
Published: September 2004

We propose a simple scheme for a spin filter by studying the coherent transport of electrons through a double-bend structure in a quantum wire with a weak lateral magnetic potential which is much weaker than the Fermi energy of the leads. Extremely large spin-polarized current in the order of microampere can be obtained because of the strong resonant behavior from the double bends. Further study suggests the robustness of this spin filter.
High-resolution transmission electron microscopic analysis of porous silicon∕silicon interface
Authors: Martín-Palma R. J. , Pascual L. , Landa A. , Herrero P. , Martínez-Duart J. M.
Published: September 2004

From high-resolution transmission electron microscopy, a strong contrast was observed in the interface between porous silicon and the silicon substrate, which was associated with the presence of high stress. It was determined that stress in the porous silicon∕Si interface is caused by dislocations and that lattice matching occurs through pairs of edge-dislocations. In addition, a high density of dislocations was also observed in the neighborhood of the Si nanocrystals that compose porous silicon. From the experimental results, a mechanism for the formation of porous silicon is proposed.
An effective cathode structure for inverted top-emitting organic light-emitting devices
Authors: Chen Chieh-Wei , Lin Chun-Liang , Wu Chung-Chih
Published: September 2004

Inverted top-emitting organic light-emitting devices (OLEDs) combine technical merits of top-emitting OLEDs and inverted OLEDs for active-matrix OLED displays. One major challenge in inverted top-emitting OLEDs, however, is to prepare a reflective bottom cathode capable of effective electron injection. In this letter, we report an effective cathode structure for enhancing the electron-injection capability of the bottom cathode in inverted top-emitting OLEDs. Such an approach does not involve handling reactive metals during fabrication and permits use of highly reflective materials such as Al and Ag as the bottom cathodes. Efficient inverted top-emitting devices employing such a cathode scheme have been demonstrated.
Focusing inside negative index materials
Authors: Brock Jeffrey B. , Houck Andrew A. , Chuang Isaac L.
Published: September 2004

Two key theoretical predictions for flat negative index lenses are that thicker lenses should have both internal and external foci, and that these foci should move linearly with small deviations in frequency. Two-dimensional electric field profiles of microwave transmission through rectangular slabs of composite wire and split-ring resonator material are presented. By scanning inside and outside the material, both internal and external foci are revealed. The power concentration around the internal focus is shown to have a negative curvature, consistent with the theoretical predictions.
Masking and scrambling in the auditory thalamus of awake rats by Gaussian and modulated noises
Authors: Martin Eugene M. , West Morris F. , Bedenbaugh Purvis H.
Published: September 2004

This paper provides a look at how modulated broad-band noises modulate the thalamic response evoked by brief probe sounds in the awake animal. We demonstrate that noise not only attenuates the response to probe sounds (masking) but also changes the temporal response pattern (scrambling). Two brief probe sounds, a Gaussian noise burst and a brief sinusoidal tone, were presented in silence and in three ongoing noises. The three noises were targeted at activating the auditory system in qualitatively distinct ways. Dynamic ripple noise, containing many random tone-like elements, is targeted at those parts of the auditory system that respond well to tones. International Collegium of Rehabilitative Audiology noise, comprised of the sum of several simultaneous streams of Schroeder-phase speech, is targeted at those parts of the auditory system that respond well to modulated sounds but lack a well defined response to tones. Gaussian noise is targeted at those parts of the auditory system that respond to acoustic energy regardless of modulation. All noises both attenuated and decreased the precise temporal repeatability of the onset response to probe sounds. In addition, the modulated noises induced context-specific changes in the temporal pattern of the response to probe sounds. Scrambling of the temporal response pattern may be a direct neural correlate of the unfortunate experience of being able to hear, but not understand, speech sounds in noisy environments.
Long-range intramolecular signaling in a tRNA synthetase complex revealed by pre-steady-state kinetics
Authors: Uter Nathan T. , Perona John J.
Published: September 2004

Pre-steady-state kinetic studies of
Escherichia coli
glutaminyl-tRNA synthetase conclusively demonstrate the existence of long-distance pathways of communication through the protein-RNA complex. Measurements of aminoacyl-tRNA synthesis reveal a rapid burst of product formation followed by a slower linear increase corresponding to
k
cat
. Thus, a step after chemistry but before regeneration of active enzyme is rate-limiting for synthesis of Gln-tRNA
Gln
. Single-turnover kinetics validates these observations, confirming that the rate of the chemical step for tRNA aminoacylation (
k
chem
) exceeds the steady-state rate by nearly 10-fold. The concentration dependence of the single-turnover reaction further reveals that the glutamine
K
d
is significantly higher than the steady-state
K
m
value. The separation of binding from catalytic events by transient kinetics now allows precise interpretation of how alterations in tRNA structure affect the aminoacylation reaction. Mutation of U35 in the tRNA anticodon loop decreases
k
chem
by 30-fold and weakens glutamine binding affinity by 20-fold, demonstrating that the active-site configuration depends on enzyme-tRNA contacts some 40 Å distant. By contrast, mutation of the adjacent G36 has very small effects on
k
chem
and
K
d
for glutamine. Together with x-ray crystallographic data, these findings allow a comparative evaluation of alternative long-range signaling pathways and lay the groundwork for systematic exploration of how induced-fit conformational transitions may control substrate selection in this model enzyme-RNA complex.
Foxa2
is required for transition to air breathing at birth
Authors: Wan Huajing , Xu Yan , Ikegami Machiko , Stahlman Mildred T. , Kaestner Klaus H. , Ang Siew-Lan , Whitsett Jeffrey A.
Published: September 2004

Toward the end of gestation in mammals, the fetal lung undergoes a process of differentiation that is required for transition to air breathing at birth. Respiratory epithelial cells synthesize the surfactant proteins and lipids that together form the pulmonary surfactant complex necessary for lung function. Failure of this process causes respiratory distress syndrome, a leading cause of perinatal death and morbidity in newborn infants. Here we demonstrate that expression of the forkhead gene
Foxa2
in respiratory epithelial cells of the peripheral lung controls pulmonary maturation at birth. Newborn mice lacking
Foxa2
expression in the lung develop severe pulmonary disease on the first day of life, with all of the morphological, molecular, and biochemical features of respiratory distress syndrome in preterm infants, including atelectasis, hyaline membranes, and the lack of pulmonary surfactant lipids and proteins. RNA microarray analysis at embryonic day 18.5 demonstrated that Foxa2-regulated expression of a group of genes mediating surfactant protein and lipid synthesis, host defense, and antioxidant production.
Foxa2
regulates a complex pulmonary program of epithelial cell maturation required for transition to air breathing at birth.
Elementary inequalities that involve two nonnegative vectors or functions
Authors: Cohen Joel E. , Kemperman J. H. B. , Zbăganu Gheorghe
Published: September 2004

We report 96 inequalities with common structure, all elementary to state but many not elementary to prove. If
n
is a positive integer,
a
= (
a
1
,...,

a
n

) and
b
= (
b
1
,...,

b
n

) are arbitrary vectors in

\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\setlength{\oddsidemargin}{-69pt}
\begin{document}
\begin{equation*}R_{+}^{n}=[0,{\infty})^{n}\end{equation*}\end{document}

, and ρ(

m
ij

) is the spectral radius of an
n
×
n
matrix with elements

m
ij

, then, for example:

\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\setlength{\oddsidemargin}{-69pt}
\begin{document}
\begin{equation*} \begin{matrix}\\ {{\sum_{i,j}}}{\mathrm{min}}((a_{i}a_{j}),(b_{i}b_{j})){\leq}{{\sum_{i,j}}}{\mathrm{min}}((a_{i}b_{j}),(b_{i}a_{j})),\\ {{\sum_{i,j}}}{\mathrm{max}}((a_{i}+a_{j}),(b_{i}+b_{j})){\geq}{{\sum_{i,j}}}{\mathrm{max}}((a_{i}+b_{j}),(b_{i}+a_{j})),\\ {\rho}({\mathrm{min}}((a_{i}a_{j}),(b_{i}b_{j}))){\leq}{\rho}({\mathrm{min}}((a_{i}b_{j}),(b_{i}a_{j}))),\\ {{\sum_{i,j}}}{\mathrm{min}}((a_{i}a_{j}),(b_{i}b_{j}))x_{i}x_{j}{\leq}{{\sum_{i,j}}}{\mathrm{min}}((a_{i}b_{j}),(b_{i}a_{j}))x_{i}x_{j},{\mathrm{for\;all\;real}}~x_{i},i=1,{\ldots},n,\\ {\int \int }{\mathrm{log}}[(f(x)+f(y))(g(x)+g(y))]d{\mu}(x)d{\mu}(y){\leq}{\int \int }{\mathrm{log}}[(f(x)+g(y))(g(x)+f(y))]d{\mu}(x)d{\mu}(y).\end{matrix} \end{equation*}\end{document}

The second inequality is obtained from the first inequality by replacing min with max and × with + and by reversing the direction of the inequality. The third inequality is obtained from the first by replacing the summation by the spectral radius. The fourth inequality is obtained from the first by taking each summand as a coefficient in a quadratic form. The fifth inequality is obtained from the first by replacing both outer summations by products, min by ×, × by +, and the nonnegative vectors
a
and
b
by nonnegative measurable functions
f
and
g
. The proofs of these inequalities are mysteriously diverse.
Molecular dynamics studies of ground state and intermediate of the hyperthermophilic indole-3-glycerol phosphate synthase
Authors: Mazumder-Shivakumar Devleena , Bruice Thomas C.
Published: September 2004

Indole-3-glycerol phosphate synthase catalyzes the terminal ring closure step in tryptophan biosynthesis. In this paper, we compare the results from molecular dynamics (MD) simulations of enzyme-bound substrate at 298, 333, 363, and 385 K and the enzyme-bound intermediate at 385 K, solvated in TIP3P water box with a
charmm
force field. Results from MD simulations agree with experimental studies supporting the observation that Lys-110 is the general acid. Based on its location in the active site during the MD simulations, Glu-210 warrants classification as the general base instead of the previously proposed Glu-159. We find that the relative population of the reactive enzyme-substrate Michaelis conformers [near attack conformers (NACs)] with temperature correlates well (correlation coefficient of 0.96) with the relative activity of this thermophilic enzyme. At higher temperature, the enzyme-substrate electrostatic interaction favors the binding of the substrate in NAC conformation, whereas, at lower temperature, the substrate is distorted and bound in a nonreactive conformation. This change is reflected in the ≈1,100-fold increase in population of NACs at 385 K relative to 298 K. The easily determined population of NACs at given temperature tells much about the thermophilic property of the enzyme. Thus, the hyperthermophilic enzyme has evolved to have optimum activity at high temperatures, and, with lowering of the temperature, the electrostatic interaction at the active site is enhanced and the structure is deformed. This model can be regarded as a general explanation for the activity of hyperthermophilic enzymes.
Problems Associated with the Recognition and Confirmation of Low-Dose Endocrine Toxicities
Authors: Ashby John
Published: September 2004

Our attempts to confirm reports of low-dose/hormetic effects in rodent endocrine toxicity studies are reviewed. It is concluded that our present failure to confirm any such effects is due, in large part, to a general lack of understanding of confounding influences and the failure of most investigators to confirm their findings before publication. The major potential confounding factor is suggested to be variability of the parameters under study within control groups, a factor that assumes increased importance when attempting to demonstrate weak low-dose effects. This is illustrated by our studies with bisphenol A in the mouse uterotrophic assay and of finasteride in the Hershberger antiandrogenicity assay. In both of these cases our ability to demonstrate a low-dose effect is dependent on whether concurrent or recent control values are used.
Setting Ambient Water Quality Standards: New York State's Nonlinear Approach for Carcinogens
Authors: Stoner Scott J. , Bogdan Kenneth G.
Published: September 2004

The New York State Department of Environmental Conservation promulgates ambient water quality standards to protect sources of potable water from contamination by toxic chemicals and other substances. Ambient water quality standards are a state program with U.S. EPA oversight, including a federal Clean Water Act requirement for “triennial review.” New York's standards are derived according to procedures in state regulation and in conjunction with the New York State Department of Health. Because standards are set at levels much below those that demonstrate effects in laboratory studies, high-to-low dose extrapolations are required. The procedures address both carcinogenic and noncarcinogenic effects. Existing regulations essentially require a linear high-to-low dose extrapolation for carcinogenic effects of a chemical (i.e., there is a finite risk at all doses above zero dose). The regulations also require a nonlinear high-to-low dose extrapolation for the noncarcinogenic effects (uncertainty factor approach) of the chemical (i.e., once below the threshold for the effect, the risk at all doses above zero is zero). New York's ongoing triennial review is addressing both standards and standard-setting procedures. Proposed revisions to the procedures, yet to be formally adopted, would allow greater flexibility and use of a nonlinear uncertainty-factor-based approach for carcinogenic effects of chemicals where warranted. The presentation will focus on the expected revisions to the procedures for carcinogenic effects.
The Influence of Very Low Doses of Cisplatin on Tumor Cell Proliferation In Vitro and on Some Hematological and Enzymatic Parameters of Healthy Rats
Authors: Malarczyk Elżbieta , Kandefer-Szerszeń Martyna , Jarosz-Wilkołazka Anna
Published: September 2004

Healthy rats had been treated for 2 or 6 weeks with 1.0 mL of 10−8 and 10−16 mg/mL of cisplatin. After 2 weeks of treatment, a significant increase in leukocyte and erythrocyte count and also in hematocrit was observed. Among leukocytes the number of neutrophils and eosinophils significantly increased. Biochemical analyses indicated a decrease in the glycogen content in the liver and kidneys after 2 weeks of treatment with low doses of cisplatin but at the end of the experiment (8th week of experiment) the stores of glycogen increased significantly. Biochemical analyses concerning the activity of some enzymes in the liver revealed a significant increase of peroxidase and acid phosphatase as well as catalase activities after 2 weeks of treatment. However, catalase was induced by a very low concentration of cisplatin, 10−16 mg/mL. After the cessation of cisplatin treatment the activity of enzymes returned to normal values.

Human lung carcinoma cell line A549 (ECACC No 86012804) was also studied after treatment with the same doses of cisplatin and inhibition of its growth was observed. The results of these experiments strongly indicated that low doses of cisplatin could be stimulating for healthy cells but cytostatic for tumor cells.

Possible mechanisms involved in the biological activity of very low cisplatin concentrations are discussed.
Chlamydia Inhibit Host Cell Apoptosis by Degradation of Proapoptotic BH3-only Proteins
Authors: Fischer Silke F. , Vier Juliane , Kirschnek Susanne , Klos Andreas , Hess Simone , Ying Songmin , Häcker Georg
Published: September 2004

Chlamydia are obligate intracellular bacteria that replicate in a vacuole inside a host cell. Chlamydial infection has been shown to protect the host cell against apoptotic stimuli. This is likely important for the ability of Chlamydia to reproduce in human cells. Here we show that resistance to apoptosis is conveyed by the destruction of the proapoptotic BH3-only proteins Bim/Bod, Puma, and Bad during infection. Apoptotic stimuli were blocked upstream of the mitochondrial activation of Bax/Bak. During infection with both species, Chlamydia trachomatis and Chlamydia pneumoniae, Bim protein gradually disappeared without noticeable changes in Bim mRNA. The disappearance was blocked by inhibitors of the proteasome. Infected cells retained sensitivity to Bim expressed by transfection, indicating functional relevance of the Bim disappearance. Fusion to Bim targeted the green fluorescent protein for destruction during infection. Analysis of truncation mutants showed that a short region of Bim containing the BH3 domain was sufficient for destruction during chlamydial infection. Like Bim, Puma and Bad proteins disappeared during infection. These results reveal a novel way by which microbes can interfere with the host cell's apoptotic machinery, and provide a molecular explanation of the cellular resistance to apoptosis during infection with Chlamydia.
Assessment of Salivary Flow Rate: Biologic Variation and Measure Error
Authors: Jongerius Peter H. , van Limbeek Jacques , Rotteveel Jan J.
Published: September 2004

Objective: To investigate the applicability of the swab method in the measurement of salivary flow rate in multiple‐handicap drooling children. To quantify the measurement error of the procedure and the biologic variation in the population.

Study Design: Cohort study.

Methods: In a repeated measurements design, a baseline series of salivary flow rates were obtained from 45 children. The within‐subject SD (SW) was calculated to express the measurements error according to a procedure introduced by Bland and Altman.

Results: Two hundred twenty‐four samples (mean 0.40 mL/min, SD 0.19 mL/min) were obtained and analyzed. The results of this study indicate that consistent scores were obtained at subsequent measurements, and good parity existed between the two measurements of salivary flow rate at each session. The SW could be estimated (0.11 mL/min), which was applied to quantify the specific variation of the salivary flow rate in our population.

Conclusion: According to Bland and Altman, the SW, which is a quantification of the measurement error and biologic variation, was found to be a useful tool to evaluate the obtained baseline salivary flow rate measurements. The swab method can be used to evaluate salivary flow rates in drooling children with cerebral palsy during interventional studies that aim to reduce saliva production.
OK‐432 Therapy for Cervical Lymphangioma
Authors: Sichel Jean‐Yves , Udassin Raphael , Gozal David , Koplewitz Benjamin Z. , Dano Itszhak , Eliashar Ron
Published: September 2004

Objective: To describe our experience with sclerosing treatment of lymphangiomas in the head and neck region by intralesional injections of OK‐432.

Study Design: Case series.

Methods: Patients with the diagnosis of a macrocystic‐type cervical lymphangioma were treated by one to three intralesional injections of OK‐432 (0.01 mg of OK‐432/1 mL of lymphangioma fluid, up to a maximum of 0.2 mg in the first injection and 0.3 mg in the second or third injections). All injections were performed under ultrasound guidance. Children were injected under sedation.

Results: Eleven patients were treated with injections of OK‐432: 7 children and 4 adults. They were followed up for a period of 5 to 68 (mean 30) months. Eight (73%) patients had complete or subcomplete resolution of the lymphangioma after one or two injections. In three (27%) cases, no response was obtained (2 cases) or the lymphangioma recurred (1 case) after two to three injections. In two cases, surgical excision was performed. There was no evidence of fibrosis around the cysts. There were no complications to OK‐432 injections.

Conclusion: Intralesional injection of OK‐432 is an effective treatment modality for macrocystic‐type lymphangiomas in the head and neck region. It has no complications, and surgical excision in case of failure is not compromised by fibrosis. Sclerosing of macrocystic‐type lymphangiomas with OK‐432 should therefore be considered before surgical excision.
Predicting Decannulation Outcomes after Distraction Osteogenesis for Syndromic Micrognathia
Authors: Sorin Alexander , McCarthy Joseph G. , Bernstein Joseph M.
Published: September 2004

Objectives: To characterize the airway anatomy by upper endoscopy in children with syndromal mandibular hypoplasia and to determine whether predistraction endoscopy is predictive of the likelihood of successful outcomes after mandibular distraction.

Study Design: Retrospective chart review.

Methods: Assessment of the upper airway by subsites was qualitatively extrapolated into a devised 4‐point scale. Upper airways were characterized and evaluated in patients on the basis of decannulation outcomes after distraction.

Results: Of the 20 patients, 12 were decannulated, and 6 remain tracheostomy dependent. The average compiled preoperative airway obstruction scores in decannulated patients (2.25) compared with those who failed decannulation (2.36) was not statistically significant (P = .291). A significant change after distraction was noted only at the levels of the oropharynx and supraglottis (P < .001). The average airway scores at these subsites in decannulated patients improved from a mean of 3.46 to 2.17 (P = .002). In patients who failed decannulation, the pre‐ and postdistraction scores also improved from 3.92 to 2.50 (P = .026). Analysis of the average postdistraction airway scores in decannulated patients (2.17) compared with failures (2.5) failed to reveal a significant difference (P = .375), suggesting that some patients remain tracheostomy dependent despite adequate mandibular expansion. Preoperative airway scores in the two groups were statistically equivocal and, therefore, not predictive of the likelihood of decannulation.

Conclusions: Preoperative airway endoscopy alone is not predictive of the likelihood of successful decannulation after distraction osteogenesis. Comparison of the airway patency after distraction revealed statistically equivocal airway caliber, suggesting that some children fail to advance to decannulation despite adequate mandibular distraction.
Symptoms of stress incontinence 1 year after childbirth: prevalence and predictors in a national Swedish sample
Authors: Schytt Erica , Lindmark Gunilla , Waldenström Ulla
Published: September 2004

Background.  The aims of the present study were to describe the prevalence of stress incontinence, as described by women themselves, 1 year after childbirth in a national sample of Swedish‐speaking women, and to identify possible predictors.

Methods.  A cohort study, including 2390 women recruited from 593 antenatal clinics in Sweden during three 1‐week periods evenly spread over 1 year (1999–2000), representing 53% of women eligible for the study and 75% of those who consented to participate. Data were collected by means of questionnaires in early pregnancy, 2 months and 1 year after the birth, and from the Swedish Medical Birth Register.

Results.  One year after the birth, 22% of the women had symptoms of stress incontinence but only 2% said it caused them major problems. The strongest predictor was urinary incontinence (overall leakage) 4–8 weeks after a vaginal delivery (OR 5.5, CI 95% 4.1–7.4) as well as after a cesarean section (OR 11.9, CI 95% 2.9–48.1). Other predictors in women with a vaginal delivery were: multiparity (OR 1.4; CI 95% 1.1–1.8), obesity (OR 1.6; CI 95% 1.1–2.4) and constipation 4–8 weeks postpartum (OR 1.4; CI 95% 1.1–1.9).

Conclusion.  Stress incontinence 1 year after childbirth is a common symptom, which could possibly be reduced by identifying women with urinary leakage at the postnatal check‐up.
Factors predicting successful DNA recovery from archival cervical smear samples
Authors: Canfell K. , Gray W. , Snijders P. , Murray C. , Tipper S. , Drinkwater K. , Beral V.
Published: September 2004

Polymerase chain reaction (PCR)‐based DNA testing of archival cervical smear slides is a useful method of retrospectively establishing the presence of the human papillomavirus (HPV) in cervical cells. A cellular DNA recovery test is performed in parallel to HPV DNA testing to ensure that sufficient cells are present and purification of sample DNA has been successfully performed. Previous studies have not comprehensively assessed DNA recovery rates in slides older than 13 years. We undertook a study to determine the factors impacting DNA recovery in 436 UK slides dating from 11 to 33 years prior to testing. Overall, a low cellular DNA recovery success rate of 29% was obtained but a strong trend was observed with increasing recovery rates the older the slides (P < 0.001). Recovery rates increased from 22% in the most recent slides collected from 1988 to 1992, to 61% in the oldest slides, collected in 1970–72. It is likely that fixation compounds incorporating acetic acid, introduced in the UK through the 1980s, have compromised subsequent attempts at PCR amplification. These findings emphasize the importance of the original fixation method in the success of DNA recovery from archival smear samples.
A Comparative Analysis of Specialization and Extinction Risk in Temperate‐Zone Bats
Authors: SAFI KAMRAN , KERTH GERALD
Published: September 2004

Abstract: Identifying the factors that influence the extinction risk of animals is essential in conservation biology because they help identify endangered species and provide the basis for their preservation. We present a comparative study that uses data from the literature on the diet and morphological specialization of European and North American bat species to investigate the effect of specialization on extinction risk. We focused on bats because many species are endangered and their high ecological diversity makes them a good model system for our purpose. After correcting for phylogenetic inertia, we compared the influence of dietary niche breadth as a measure of food specialization and of wing morphology as a measure of foraging strategy, habitat adaptation, and migratory ability on the vulnerability of 35 insectivorous bat species. Our results do not support the hypothesis that a narrow dietary niche breadth is related to high extinction risk. Instead they suggest that habitat specialization, which is reflected in wing morphology, influences the extinction risk of bats. Our study shows that an initial risk assessment in temperate‐zone bats could be based on data of wing morphology but not on dietary data obtained from fecal analyses.
International Trade Status and Crisis for Snake Species in China
Authors: ZHOU ZHIHUA , JIANG ZHIGANG
Published: September 2004

Abstract:  In recent years, the purchase of snakes for leather, food, and traditional medicine has increased in China, which has greatly reduced certain snake populations. Trade records show that since the 1990s, with respect to some species of snakes, China is changing from a net export country to a net import country. We analyzed data on international trade in snake species, concentrating, in particular, on trade dynamics and species composition. The overall number of snakes exported appears to have decreased in the last 10 years. However, the number of snakes imported during this period has increased steadily. Many species of snakes that are traded in significant numbers are endangered or threatened species. To conserve snakes in China, we recommended that the Chinese government and the international conservation community take the following actions: enhance legislation and list several species in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) appendices; register all snake farms in China; carry out population and market surveys; monitor the dynamics of trade; encourage biological research; encourage change in food habits; and enhance cooperation between Hong Kong and mainland China.
The protein kinase C system in focal adenitis of the lacrimal gland in the non‐obese diabetic mouse model for Sjögren's syndrome
Authors: Tensing E‐K. , Törnwall J. , Hukkanen M. , Nordström D. C. E. , Konttinen Y. T.
Published: September 2004

Purpose:  Non‐obese diabetic (NOD) mice develop an autoimmune exocrinopathy characterized by hyposecretion of saliva and acinar cell atrophy. As the protein kinase C (PKC) system is involved in the signal transduction pathways associated with primary secretion and acinar cell differentiation and growth, the PKC profile was analysed in NOD mice.

Methods:  Lacrimal glands from BALB/c, NOD, NOD scid and transgenic NOD × interferon‐γ (IFN‐γ) mice were analysed for their PKC profiles using antibodies against several conventional (α, β, γ), novel (δ, ε, θ) and atypical (ι, λ) PKC isoforms using the Streptavidin/HRP (horseradish peroxidase) method.

Results:  Acinar cells in BALB/c control mice expressed two conventional (α, β) and two atypical (ι, λ) PKC isoforms. In NOD and transgenic NOD × IFN‐γ mice the same isoforms were more strongly expressed. NOD scid mice lacked all other PKC isoforms except PKC λ.

Conclusions:  Co‐expression of several PKC isoforms in single cell type may be necessary for transcriptional activation and agonist‐induced secretory responses. Hyposecretion in NOD mice was paradoxically associated with up‐regulation of the PKC system. This may be associated with a deranged signal transduction per se rather than with the immune‐inflammation, as the transgenic NOD × IFN‐γ mice showed similar PKC profiles. The NOD model does not reproduce lack/consumption of PKC II and PKC as in Sjögren's syndrome. This may be because the receptor autoantibodies in mice are directed against the adrenergic, not muscarinic, receptors. Lack and/or low level PKC expression in NOD scid mouse may explain the excessive acinar cell apoptosis in this model.
Marius Tscherning (1854–1939): his life and work in optical physiology
Authors: Norn Mogens , Jensen Ove A.
Published: September 2004

Background:  This article is based on Tscherning's papers, scientific protocols and letters and the many original instruments kept in the Medical History Museum in Copenhagen, Denmark.

History:  In 1884, after his thesis concerning the frequency of myopia in Denmark, Tscherning became adjunct director of the ophthalmological laboratory at the Sorbonne University in Paris. He was called back to Denmark in 1910 and appointed professor of ophthalmology and head of the Eye Department, Rigshospitalet. He continued to work scientifically as emeritus from 1925.

Achievements:  Tscherning published about 100 scientific papers, mainly concerning optical physiology (i.e. the aetiology of myopia, entoptic phenomena, Purkinje pictures, the polygonal pattern provoked by corneal rubbing, etc.). He studied the law of Listing and projections depending on torsion of the eye and invented the ophthalmophacometer, which measures the changes that occur in the front and back curvatures of the crystalline lens during accommodation. Tscherning also studied aberration and calculated and constructed forward bulging periscopic (punctal) spectacle lenses. In addition, he studied colour sense, dark vision and adaptation.
Assessment of Geometry Correction Functions of Tanker Knuckle Details Based on Fatigue Tests and Finite-Element Analysis
Authors: Garbatov Y. , Rudan S. , Guedes Soares C.
Published: September 2004

The paper analyzes the fatigue crack growth of knuckle detail typical of tankers. An approach for evaluation of the fatigue life based on fracture mechanics is presented, where a Paris-Erdogan crack-growth law is applied. A geometry correction function is determined from fatigue test data. A closed-form equation is proposed for fatigue life estimation. The results obtained from a fatigue test and the calculated fatigue lives are compared.
The Reconstruction of Significant Wave Height Time Series by Using a Neural Network Approach
Authors: Arena Felice , Puca Silvia
Published: September 2004

A Multivariate Neural Network (MNN) algorithm is proposed for the reconstruction of significant wave height time series, without any increase of the error of the MNN output with the number of modelled data. The algorithm uses a weighted error function during the learning phase, to improve the modelling of the higher significant wave height. The ability of the MNN to reconstruct sea storms is tested by applying the equivalent triangular storm model. Finally an application to the NOAA buoys moored off California shows a good performance of the MNN algorithm, both during sea storms and calm time periods.
Seasonal Modeling of Multivariate Distributions of Metocean Parameters With Application to Marine Operations
Authors: Fouques Se´bastien , Myrhaug Dag , Nielsen Finn Gunnar
Published: September 2004

Statistical information about the joint occurrence of metocean parameters is of importance for many offshore activities. For instance, in marine operations, environmental limitations may be brought about by both wind and wave conditions. Thus, knowledge of their joint occurrence is important as the persistence duration (i.e., the duration of the sea state persistence above or beneath a given level) and the seasonal dependence of wind and waves appear to be of large interest. However, such a modeling becomes difficult as the number of considered variables increases, especially when utilizing a common parameterization of some conditional distributions. This paper proposes a general methodology that aims at modeling seasonal joint distributions of n such parameters from their correlation structure and the n marginal distributions fitted by generalized gamma ones. Two methods are proposed in order to derive an approximate joint distribution from the modeled margins. The first one matches the correlation matrix only, whereas the second one, which is based on a multivariate Hermite polynomials expansion of the multinormal distribution, is able to match joint moments of order higher than two. However, more restrictive conditions are shown by the latter. An application to the simple example of the joint occurrence of significant wave height and the mean wind velocity at the 10m elevation is used to illustrate the methods. Eventually, examples of applications like simultaneous persistence of wind and wave conditions as well as seastate forecasting from statistics are given.
Low Reynolds Number Viscous Flow in an Alveolated Duct
Authors: Karl Alexander , Henry Frank S. , Tsuda Akira
Published: September 2004

Flow visualization studies and supplementary numerical simulations are carried out on slow flow through a model alveolated duct. The results reveal that the type of flow that develops in the alveoli, or cavities, is controlled by the ratio of the depth to the width of the cavity and by the ratio of cavity volume to duct volume. While weak, the slowly rotating flow in the cavity is thought to be important to the convective transport of heat and mass transfer to, or from, the walls of the cavity. The relevance of these finding to particle transport and deposition deep in the lung is discussed.
Analysis of the Dynamic Permeation Experiment with Implication to Cartilaginous Tissue Engineering
Authors: Gu W. Y. , Sun D. N. , Lai W. M. , Mow V. C.
Published: September 2004

In the present study, a 1-D dynamic permeation of a monovalent electrolyte solution through a negatively charged-hydrated cartilaginous tissue is analyzed using the mechano-electrochemical theory developed by Lai et al. (1991) as the constitutive model for the tissue. The spatial distributions of stress, strain, fluid pressure, ion concentrations, electrical potential, ion and fluid fluxes within and across the tissue have been calculated. The dependencies of these mechanical, electrical and physicochemical responses on the tissue fixed charge density, with specified modulus, permeability, diffusion coefficients, and frequency and magnitude of pressure differential are determined. The results demonstrate that these mechanical, electrical and physicochemical fields within the tissue are intrinsically and nonlinearly coupled, and they all vary with time and depth within the tissue.
Maternal Calcium Intake and Offspring Blood Pressure
Authors: Gillman Matthew W. , Rifas-Shiman Sheryl L. , Kleinman Ken P. , Rich-Edwards Janet W. , Lipshultz Steven E.
Published: September 2004

Background—

Few data exist on the intergenerational influence of calcium intake during pregnancy on offspring blood pressure.

Methods and Results—

As part of the ongoing US prospective cohort study Project Viva, we analyzed 4091 Dinamap blood pressure measurements from 936 six-month-old infants whose mothers had completed food frequency questionnaires during the second trimester of pregnancy. We used mixed models to estimate effects of maternal calcium intake on offspring systolic blood pressure. Mean±SD daily total maternal calcium intake was 1494±523 mg, consisting of 1230±486 mg from foods and 264±191 mg from supplements. Mean±SD 6-month blood pressure was 89.9±12.9 mm Hg. From bottom to top quartile of dietary calcium from foods adjusted for energy intake and measurement conditions, mean infant systolic blood pressures were 91.0, 90.2, 90.9, and 90.2 mm Hg (trend
P
=0.62). From calcium supplements only, the values were 91.5, 90.2, 90.4, and 88.4 mm Hg (trend
P
=0.006). After further adjustment for demographic, anthropometric, dietary, social, and economic variables, the decrease in 6-month systolic blood pressure was −3.0 mm Hg (95% CI, −4.9 to −1.1) for each 500-mg increment of maternal supplemental calcium intake during pregnancy. We did not find evidence of effect modification by maternal vitamin D or potassium intake or by infant body mass index. First-trimester calcium intake was not associated with offspring blood pressure.

Conclusions—

These observational data suggest that supplementing maternal midgestational calcium intake may lower offspring blood pressure, thus helping to prevent hypertension in the next generation.
Endocannabinoids Acting at Cannabinoid-1 Receptors Regulate Cardiovascular Function in Hypertension
Authors: Bátkai Sándor , Pacher Pál , Osei-Hyiaman Douglas , Radaeva Svetlana , Liu Jie , Harvey-White Judith , Offertáler László , Mackie Ken , Rudd M. Audrey , Bukoski Richard D. , Kunos George
Published: September 2004

Background—

Endocannabinoids are novel lipid mediators with hypotensive and cardiodepressor activity. Here, we examined the possible role of the endocannabinergic system in cardiovascular regulation in hypertension.

Methods and Results—

In spontaneously hypertensive rats (SHR), cannabinoid-1 receptor (CB
1
) antagonists increase blood pressure and left ventricular contractile performance. Conversely, preventing the degradation of the endocannabinoid anandamide by an inhibitor of fatty acid amidohydrolase reduces blood pressure, cardiac contractility, and vascular resistance to levels in normotensive rats, and these effects are prevented by CB
1
antagonists. Similar changes are observed in 2 additional models of hypertension, whereas in normotensive control rats, the same parameters remain unaffected by any of these treatments. CB
1
agonists lower blood pressure much more in SHR than in normotensive Wistar-Kyoto rats, and the expression of CB
1
is increased in heart and aortic endothelium of SHR compared with Wistar-Kyoto rats.

Conclusions—

We conclude that endocannabinoids tonically suppress cardiac contractility in hypertension and that enhancing the CB
1
-mediated cardiodepressor and vasodilator effects of endogenous anandamide by blocking its hydrolysis can normalize blood pressure. Targeting the endocannabinoid system offers novel therapeutic strategies in the treatment of hypertension.
Lipoprotein-Associated Phospholipase A
2
Adds to Risk Prediction of Incident Coronary Events by C-Reactive Protein in Apparently Healthy Middle-Aged Men From the General Population
Authors: Koenig Wolfgang , Khuseyinova Natalie , Löwel Hannelore , Trischler Gerlinde , Meisinger Christa
Published: September 2004

Background—

Chronic inflammation represents an essential feature of the atherosclerotic process. Lipoprotein-associated phospholipase A
2
(Lp-PLA
2
), an enzyme mainly produced by monocytes/macrophages, generates potent proinflammatory products.

Methods and Results—

Plasma concentrations of Lp-PLA
2
were determined by ELISA in 934 apparently healthy men aged 45 to 64 years sampled from the general population in 1984 and followed up until 1998. During this period, 97 men experienced a coronary event diagnosed according to the MONICA (MONItoring of trends and determinants in CArdiovascular disease) protocol. Baseline levels of Lp-PLA
2
were higher in subjects who experienced an event than in event-free subjects (295±113 versus 263±79 ng/mL,
P
<0.01). Lp-PLA
2
was positively correlated with total cholesterol (
R
=0.30,
P
<0.0001) and age (
R
=0.12,
P
=0.001), was only slightly correlated with HDL cholesterol (
R
=0.09,
P
=0.005) and C-reactive protein
R
=0.06,
P
=0.06), but was not correlated with body mass index or blood pressure. In a Cox model, a 1-SD increase in Lp-PLA
2
was associated with risk of future coronary events (hazard ratio [HR] 1.37, 95% CI 1.16 to 1.62). After controlling for potential confounders, the HR was attenuated but remained statistically significant (HR 1.23, 95% CI 1.02 to 1.47). Further inclusion of C-reactive protein in the model did not appreciably affect its predictive ability (HR 1.21, 95% CI 1.01 to 1.45).

Conclusions—

Elevated levels of Lp-PLA
2
appeared to be predictive of future coronary events in apparently healthy middle-aged men with moderately elevated total cholesterol, independent of CRP. This suggests that Lp-PLA
2
and CRP may be additive in their ability to predict risk of coronary heart disease.
Prognostic Value of Systemic Endothelial Dysfunction in Patients With Acute Coronary Syndromes
Authors: Fichtlscherer Stephan , Breuer Susanne , Zeiher Andreas M.
Published: September 2004

Background—

Endothelial vasodilator dysfunction may serve as a marker integrating the vascular risk of an individual; however, whether systemic vasodilator function predicts disease progression and cardiovascular event rates in patients with manifest acute coronary syndromes (ACS) is unknown.

Methods and Results—

In 198 patients with angiographically documented ACS, forearm blood flow (FBF) responses to acetylcholine (ACH; 10 to 50 μg/min) and sodium nitroprusside (SNP; 2 to 8 μg/min) were measured by venous occlusion plethysmography before hospital discharge within 5 days of an episode of an ACS. Cardiovascular events (cardiovascular death, myocardial infarction, and ischemic stroke) served as outcome variables over a mean follow-up period of 47.7±15.1 months. Patients who experienced cardiovascular events during follow-up (n=31) had a significantly reduced vasodilator response to ACH (
P
<0.05) and SNP (
P
<0.05). By multivariate analysis, vasodilator response to ACH and elevated troponin T serum levels were the only significant (
P
<0.05) independent predictors of a poor prognosis, even after adjustment for traditional cardiovascular risk factors, concurrent medication, invasive treatment strategy, and C-reactive protein serum levels. Recovery of endothelium-dependent vasoreactivity as assessed by repeated FBF assessment 8 weeks after the index measurement after the ACS predicted further event-free survival in a subset of 78 patients.

Conclusions—

Systemic endothelium-dependent vasoreactivity predicts recurrence of instability and cardiovascular event rates in patients with ACS. Furthermore, the recovery of systemic endothelial function is associated with event-free survival. Assessment of systemic vasoreactivity, measured by a minimally invasive test, provides important prognostic information in addition to that derived from traditional risk factor assessment in patients with ACS.