bluuebunny/crossref_metadata_2025 huggingface dataset:
Clopidogrel-Precipitated Rhabdomyolysis in a Stable Heart Transplant Patient
Authors: Burton Jeffrey R , Burton Ilene , Pearson Glen J
Published: January 2007

Objective:

To report the case of an orthotopic heart transplant recipient who developed rhabdomyolysis precipitated by the addition of clopidogrel to the existing regimen of cyclosporine and atorvastatin, which had been tolerated for more than 3 years without adverse effects or laboratory evidence of myositis.

Case Summary:

Fourteen years after cardiac transplantation, a 58-year-old woman began a planned 4 week course of clopidogrel 75 mg/day following coronary angioplasty and placement of a stent in the left circumflex coronary artery. Almost 4 weeks later, she presented with severe muscle pain and weakness and laboratory evidence of rhabdomyolysis, with marked elevations of plasma creatine kinase (96 000 U/L) and urine myoglobin (332 872 μg/L.) as well as early acute renal failure (serum creatinine 2.9 mg/dL). Symptoms and laboratory abnormalities resolved with cessation of cyclosporine, atorvastatin, and clopidogrel. Clopidogrel was not restarted, while atorvastatin and cyclosporine were; the patient had no recurrence of symptoms up to 15 months later.

Discussion:

Both atorvastatin and cyclosporine, as well as clopidogrel's active thiol derivative, are metabolized by the cytochrome P450 3A4 isoenzyme. Cyclosporine is also a moderate inhibitor of this isoenzyme. We postulate that competition between atorvastatin and clopidogrel for CYP3A4 receptors, already partially inhibited by cyclosporine, led to increased atorvastatin concentrations, resulting in the acute onset of rhabdomyolysis. This theory is further supported by the patient's continued ability to tolerate the combination of atorvastatin and cyclosporine, without clopidogrel, on rechallenge. Use of the Naranjo probability scale revealed that rhabdomyolysis was probably precipitated by the addition of clopidogrel to the stable baseline regimen of cyclosporine and atorvastatin.

Conclusions:

Practitioners must be conscious of the potential for adverse effects when prescribing clopidogrel to heart transplant patients who are concomitantly receiving cyclosporine and a statin. If concomitant administration is required, careful clinical and laboratory monitoring of the patient is necessary.
Caregiver Health Literacy and the Use of Child Health Services
Authors: Sanders Lee M. , Thompson Valerie T. , Wilkinson James D.
Published: January 2007

OBJECTIVES. Eighty million US adults have low health literacy, a risk factor for increased health care use among adults. The purpose of this work was to assess the association between caregiver health literacy and the use and cost of child health services.

METHODS. We conducted a cross-sectional study of caregiver-child dyads from a sample of children aged 12 months to 12 years presenting to the pediatric emergency department of an urban, public hospital. Caregiver health literacy was measured by the Short Test of Functional Health Literacy in their preferred language (English or Spanish). Child health care use was measured by a 12-month retrospective review of the public hospital system's electronic database and of state Medicaid billing records for 4 types of visits: preventive care, urgent care, emergency care, and hospital care. Cost of child health care use was provided by Medicaid billing records. Multivariate analysis included caregiver education, age, and language proficiency, as well as child age, special health care needs, ethnicity, and health-insurance coverage.

RESULTS. A total of 290 dyads were enrolled in the study. Twenty-two percent of caregivers had low (inadequate or marginal) health literacy. Caregivers with low health literacy were more likely to have less than a high school education, to have limited English proficiency, and to have been born outside the United States. There were no differences in health care use or cost between children of caregivers with low health literacy and children of caregivers with adequate health literacy. Three caregiver characteristics were associated with increased use of child health care services: born outside the United States, age at child’s birth <24 years, and limited English proficiency.

CONCLUSIONS. One in 5 caregivers of young children has low health literacy. Caregiver health literacy, however, was not associated with disparities in the use of child health services in this inner-city, ethnic minority population.
Adolescent Depression Screening in Primary Care: Feasibility and Acceptability
Authors: Zuckerbrot Rachel A. , Maxon Laura , Pagar Dana , Davies Mark , Fisher Prudence W. , Shaffer David
Published: January 2007

OBJECTIVE. Despite available depression treatments, only one fourth to one third of depressed adolescents are receiving care. The problem of underdiagnosis and underreferral might be redressed if assessment of suicidality and depression became a more formal part of routine pediatric care. Our purpose for this study was to explore the feasibility and acceptability of implementing adolescent depression screening into clinical practice.

METHODS. In this study we implemented a 2-stage adolescent identification protocol, a first-stage pen-and-paper screen and a second-stage computerized assessment, into a busy primary care pediatric practice. Providers tracked the number of eligible patients screened at both health maintenance and urgent care visits and provided survey responses regarding the burden that screening placed on the practice and the effect on patient/parent-provider relationships.

RESULTS. Seventy-nine percent of adolescent patients presenting for health maintenance visits were screened, as were the majority of patients presenting for any type of visit. The average completion time for the paper screen was 4.6 minutes. Providers perceived parents and patients as expressing more satisfaction than dissatisfaction with the screening procedures and that the increased time burden could be handled. All providers wished to continue using the paper screen at the conclusion of the protocol.

CONCLUSIONS. Instituting universal systematic depression screening in a practice with a standardized screening instrument met with little resistance by patients and parents and was well perceived and accepted by providers.
A Randomized, Controlled Trial of Heparin Versus Placebo Infusion to Prolong the Usability of Peripherally Placed Percutaneous Central Venous Catheters (PCVCs) in Neonates: The HIP (Heparin Infusion for PCVC) Study
Authors: Shah Prakesh S. , Kalyn Angela , Satodia Prakash , Dunn Michael S. , Parvez Boriana , Daneman Alan , Salem Shia , Glanc Phyllis , Ohlsson Arne , Shah Vibhuti
Published: January 2007

BACKGROUND. Mechanical and infectious complications shorten the effective duration of peripherally inserted central venous catheters. Heparin use to prevent such complications and prolong the usability of peripherally inserted central venous catheters is inconclusive.

OBJECTIVE. Our goal was to evaluate the effectiveness of heparin in prolonging the usability of peripherally inserted central venous catheters in neonates.

DESIGN/METHODS. We performed a multicenter, randomized, controlled trial of heparin infusion (0.5 U/kg per hour) versus placebo for peripherally inserted central venous catheters in neonates. The primary outcome was duration of catheter use. Secondary outcomes were occlusion, catheter-related sepsis, thrombosis, and adverse effects of heparin. To detect a 168-hour (1-week) difference in the duration of catheter use, 192 patients were needed. Kaplan-Meier and Cox regression analyses were performed.

RESULTS. A total of 201 neonates were enrolled (heparin group: n = 100; control group: n = 101). Baseline demographics were similar between the groups. Duration of catheter use was longer in the infants in the heparin versus the placebo group. Study center, gender, birth weight, and type and position of the catheter were not predictors of duration of catheter use. For those in the heparin versus the placebo group, the incidence of elective catheter removal (therapy completed) was 63% vs 42%, of occlusion was 6% vs 31%, of thrombosis was 20% vs 21%, and of catheter-related sepsis was 10% vs 6%, respectively. No adverse events were noted.

CONCLUSIONS. Heparin infusion prolonged the duration of peripherally inserted central venous catheter usability, which permitted a higher percentage of neonates to complete therapy without increasing adverse effects.
Breastfeeding and Infant Eczema in the First Year of Life in the KOALA Birth Cohort Study: A Risk Period–Specific Analysis
Authors: Snijders Bianca E. P. , Thijs Carel , Kummeling Ischa , Penders John , van den Brandt Piet A.
Published: January 2007

OBJECTIVE. We studied the association between breastfeeding and eczema, taking into account the possible influence of reverse causation, with risk period–specific analyses.

METHODS. Information on breastfeeding, determinants, and outcomes at 1 year of age was collected with repeated questionnaires for 2405 mother-infant pairs participating in the KOALA (Child, Parent and Health: Lifestyle and Genetic Constitution [in Dutch]) birth cohort study. By using multivariate logistic regression analysis, we compared an overall analysis with risk period–specific analyses.

RESULTS. By the age of 1 year, 535 infants (22.2%) had developed eczema. In an overall analysis, we found a weak nonsignificant trend toward a reduced risk of eczema in the first year of life with increasing duration of breastfeeding (lowest risk for those breastfed for ≥7 months versus never breastfed). In the risk period–specific analysis (confined to infants “at risk” for eczema onset after 3 months of age), no indication for reverse causation was found (results were not very different, compared with the overall analysis). Infants who were breastfed from birth on had a slightly (although not statistically significantly) increased risk for eczema in the first 3 months of life, compared with infants who were formula fed from birth on.

CONCLUSIONS. Our results indicated that no strong effect of breastfeeding on eczema in the first year of life was present. This conclusion was strengthened by risk period–specific analysis, which made the influence of reverse causation unlikely.
Lactobacillus reuteri(American Type Culture Collection Strain 55730) Versus Simethicone in the Treatment of Infantile Colic: A Prospective Randomized Study
Authors: Savino Francesco , Pelle Emanuela , Palumeri Elisabetta , Oggero Roberto , Miniero Roberto
Published: January 2007

OBJECTIVE. The goal was to test the hypothesis that oral administration of Lactobacillus reuteri in a prospective randomized study would improve symptoms of infantile colic.

METHODS. Ninety breastfed colicky infants were assigned randomly to receive either the probiotic L reuteri (108 live bacteria per day) or simethicone (60 mg/day) each day for 28 days. The mothers avoided cow's milk in their diet. Parents monitored daily crying times and adverse effects by using a questionnaire.

RESULTS. Eighty-three infants completed the trial: 41 in the probiotic group and 42 in the simethicone group. The infants were similar regarding gestational age, birth weight, gender, and crying time at baseline. Daily median crying times in the probiotic and simethicone groups were 159 minutes/day and 177 minutes/day, respectively, on the seventh day and 51 minutes/day and 145 minutes/day on the 28th day. On day 28, 39 patients (95%) were responders in the probiotic group and 3 patients (7%) were responders in the simethicone group. No adverse effects were reported.

CONCLUSIONS. In our cohort, L reuteri improved colicky symptoms in breastfed infants within 1 week of treatment, compared with simethicone, which suggests that probiotics may have a role in the treatment of infantile colic.
No Improvement in Outcome of Nationwide Extremely Low Birth Weight Infant Populations Between 1996–1997 and 1999–2000
Authors: Tommiska Viena , Heinonen Kirsti , Lehtonen Liisa , Renlund Martin , Saarela Timo , Tammela Outi , Virtanen Martti , Fellman Vineta
Published: January 2007

OBJECTIVE. Our goal was to investigate whether outcome in extremely low birth weight infants changes over time in Finland.

PATIENTS AND METHODS. All infants with a birth weight <1000 g born in Finland in 1996–1997 and 1999–2000 were included in the study. Perinatal and follow-up data were collected in a national extremely low birth weight infant research register. Data concerning cerebral palsy and visual impairment were obtained from hospitals, the national discharge, and visual impairment registers.

RESULTS. A total of 529 and 511 extremely low birth weight infants were born during 1996–1997 and 1999–2000. No changes were detected in prenatal, perinatal, neonatal, and postneonatal mortality rates between the periods. The survival rates including stillborn infants were 40% and 44%. The incidence of respiratory distress syndrome and septicemia increased from 1996–1997 to 1999–2000 (75% vs 83% and 23% vs 31%). The overall incidence of intraventricular hemorrhage increased (29% vs 37%), but the incidence of intraventricular hemorrhage grades 3 through 4 did not (16% vs 17%). The rates of oxygen dependency at the age corresponding with 36 gestational weeks, retinopathy of prematurity stages 3 to 5, cerebral palsy, and severe visual impairment did not change. Mortality remained higher in 1 university hospital area during both periods compared with the other 4 areas, but no regional differences in morbidity were detected during the later period.

CONCLUSIONS. No significant changes were detected in birth or mortality rate in extremely low birth weight infants born in Finland during the late 1990s, but some neonatal morbidities seemed to increase. Regional differences in mortality were detected in both cohorts. Repeated long-term follow-up studies on geographically defined very preterm infant cohorts are needed for establishing reliable outcome data of current perinatal care. Regional differences warrant thorough audits to assess causalities.
Binge Drinking and Associated Health Risk Behaviors Among High School Students
Authors: Miller Jacqueline W. , Naimi Timothy S. , Brewer Robert D. , Jones Sherry Everett
Published: January 2007

OBJECTIVES. Underage drinking contributes to the 3 leading causes of death (unintentional injury, homicide, and suicide) among persons aged 12 to 20 years. Most adverse health effects from underage drinking stem from acute intoxication resulting from binge drinking. Although binge drinking, typically defined as consuming ≥5 drinks on an occasion, is a common pattern of alcohol consumption among youth, few population-based studies have focused specifically on the characteristics of underage binge drinkers and their associated health risk behaviors.

METHODS. We analyzed data on current drinking, binge drinking, and other health risk behaviors from the 2003 National Youth Risk Behavior Survey. Prevalence estimates and 95% confidence intervals were calculated by using SAS and SUDAAN statistical software. Logistic regression was used to examine the associations between different patterns of alcohol consumption and health risk behaviors.

RESULTS. Overall, 44.9% of high school students reported drinking alcohol during the past 30 days (28.8% binge drank and 16.1% drank alcohol but did not binge drink). Although girls reported more current drinking with no binge drinking, binge-drinking rates were similar among boys and girls. Binge-drinking rates increased with age and school grade. Students who binge drank were more likely than both nondrinkers and current drinkers who did not binge to report poor school performance and involvement in other health risk behaviors such as riding with a driver who had been drinking, being currently sexually active, smoking cigarettes or cigars, being a victim of dating violence, attempting suicide, and using illicit drugs. A strong dose-response relationship was found between the frequency of binge drinking and the prevalence of other health risk behaviors.

CONCLUSIONS. Binge drinking is the most common pattern of alcohol consumption among high school youth who drink alcohol and is strongly associated with a wide range of other health risk behaviors. Effective intervention strategies (eg, enforcement of the minimum legal drinking age, screening and brief intervention, and increasing alcohol taxes) should be implemented to prevent underage alcohol consumption and adverse health and social consequences resulting from this behavior.
Pediatric Hospital and Intensive Care Unit Capacity in Regional Disasters: Expanding Capacity by Altering Standards of Care
Authors: Kanter Robert K. , Moran John R.
Published: January 2007

BACKGROUND. Federal planners have suggested that one strategy to accommodate disaster surges of 500 inpatients per million population would involve altering standards of care. No data are available indicating the extent of alterations necessary to meet disaster surge targets.

OBJECTIVE. Our goal was to, in a Monte Carlo simulation study, determine the probability that specified numbers of children could be accommodated for PICU and non-ICU hospital care in a disaster by a set of strategies involving altered standards of care.

METHODS. Simulated daily vacancies at each hospital in New York City were generated as the difference between peak capacity and daily occupancy (generated randomly from a normal distribution on the basis of empirical data for each hospital). Simulations were repeated 1000 times. Capacity for new patients was explored for normal standards of care, for expansion of capacity by a discretionary 20% increase in vacancies by altering admission and discharge criteria, and for more strictly reduced standards of care to double or quadruple admissions for each vacancy. Resources were considered to reliably serve specified numbers of patients if that number could be accommodated with a probability of 90%.

RESULTS. Providing normal standards of care, hospitals in New York City would reliably accommodate 250 children per million age-specific population. Hypothetical strict reductions in standards of care would reliably permit hospital care of 500 children per million, even if the disaster reduced hospital resources by 40%. On the basis of historical experience that as many as 30% of disaster casualties may be critically ill or injured, existing pediatric intensive care beds will typically be insufficient, even with modified standards of care.

CONCLUSIONS. Extending resources by hypothetical alterations of standards of care would usually satisfy targets for hospital surge capacity, but ICU capacity would remain inadequate for large disasters.
Improving runoff modelling using satellite-derived snow covered area?
Authors: Udnæs Hans-Christian , Alfnes Eli , Andreassen Liss M.
Published: January 2007

Operational use of satellite-observed snow covered area (SCA) in the HBV model was studied in order to improve the spring flood prediction. The study included calibration of HBV models against both discharge and SCA, against discharge only, and updating of the HBV models based on satellite observed SCA. Ten test catchments were selected for the study. The results confirmed that HBV models calibrated against SCA in addition to discharge simulate discharge nearly as well as models calibrated against discharge only. The simulated SCA was markedly improved when SCA was included in the calibration.

Deviations between observed and simulated SCA was used to trigger model updates. In such cases, the model input (precipitation and temperature) was adjusted until a reasonable fit in the SCA was obtained. The results of the updates were ambiguous. Only 28% of the updates improved the runoff simulations. Improved simulations were most frequent at large SCA values.

SCA derived from radar and optical satellite sensors differed considerably. Harmonisation is required before both types of data can be integrated in the same model simulations.
Optimal model for warehouse location and retailer allocation
Authors: Gill Avninder , Ishaq Bhatti M.
Published: January 2007

Warehouse location and retailer allocation is a high‐level strategic decision problem that is commonly encountered by logisticians and supply chain managers, especially during the supply chain design phase. Considering the product distribution cost and warehouse capital cost trade‐offs, this paper models the warehouse location and retailer allocation problem as a 0–1 integer programming problem and provides an efficient two‐stage set covering heuristic algorithm to solve large‐sized problems. Finally, concluding remarks and some recommendations for further research are also presented. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of oral vitamin E supplementation on oxidative stress in guinea‐pigs with short‐term hypothermia
Authors: Aslan Leyla , Meral Ismail
Published: January 2007

Effects of oral vitamin E supplementation on blood malondialdehyde (MDA), glutathione (GSH) and vitamin E levels and superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) enzyme activities in acute hypothermia of guinea‐pigs were investigated. Thirty male guinea pigs, weighing 500–800 g were randomly divided into one of three experimental groups: A (control, without cooling), B (hypothermic) and C (hypothermic with vitamin E supplementation). The guinea‐pigs of group C received daily oral supplementation of 460 mg kg−1 bw vitamin E for 4 days before inducing hypothermia. Twenty‐four hours after the last vitamin E supplementation, the guinea‐pigs of the B and C groups were cooled by immersion into cold water (10–12°C), and the control guinea‐pigs were immersed into water of body temperature (37°C) up to the neck for 5 min without using any anaesthetic or tranquilizer. Rectal body temperatures of groups were measured and blood samples for biochemical analysis were collected immediately after the cooling. The body temperature, GSH and vitamin E levels and GSH‐Px enzyme activity of hypothermic guinea‐pigs were lower (p < 0.05), but SOD enzyme activity was not different (p > 0.05) from those of control animals. Although, the body temperature of hypothermic with vitamin E supplementation group was lower (p < 0.05), all other parameters of this group were not different (p > 0.05) from the controls. It was concluded that oral supplementation of vitamin E can alleviate the lipid peroxidation‐induced disturbances associated with hypothermia by increasing the serum vitamin E level to normal. However, more studies are needed to prove whether this vitamin can improve quality of life during the cold seasons. Copyright © 2007 John Wiley & Sons, Ltd.
Protective effects of N‐acetyl‐L‐cysteine against acute carbon tetrachloride hepatotoxicity in rats
Authors: Maksimchik Yu. Z. , Lapshina E. A. , Sudnikovich E. Yu. , Zabrodskaya S. V. , Zavodnik I. B.
Published: January 2007

In recent years, N‐acetyl‐L‐cysteine (NAC) has been widely investigated as a potentially useful protective and antioxidative agent to be applied in many pathological states. The aim of the present work was further evaluation of the mechanisms of the NAC protective effect under carbon tetrachloride‐induced acute liver injuries in rats. The rat treatment with CCl4 (4 g/kg, intragastrically) caused pronounced hepatolysis observed as an increase in blood plasma bilirubin levels and hepatic enzyme activities, which agreed with numerous previous observations. The rat intoxication was accompanied by an enhancement of membrane lipid peroxidation (1.4‐fold) and protein oxidative damage (protein carbonyl group and mixed protein‐glutathione disulphide formations) in the rat liver. The levels of nitric oxide in blood plasma and liver tissue significantly increased (5.3‐ and 1.5‐fold, respectively) as blood plasma triacylglycerols decreased (1.6‐fold). The NAC administration to control and intoxicated animals (three times at doses of 150 mg/kg) elevated low‐molecular‐weight thiols in the liver. The NAC administration under CCl4‐induced intoxication prevented oxidative damage of liver cells, decreased membrane lipid peroxidation, protein carbonyls and mixed protein‐glutathione disulphides formation, and partially normalized plasma triacylglycerols. At the same time the NAC treatment of intoxicated animals did not produce a marked decrease of the elevated levels of blood plasma ALT and AST activities and bilirubin. The in vitro exposure of human red blood cells to NAC increased the cellular low‐molecular‐weight thiol levels and retarded tert‐butylhydroperoxide‐induced cellular thiol depletion and membrane lipid peroxidation as well as effectively inhibited hypochlorous acid‐induced erythrocyte lysis. Thus, NAC can replenish non‐protein cellular thiols and protect membrane lipids and proteins due to its direct radical‐scavenging properties, but it did not attenuate hepatotoxicity in the acute rat CCl4‐intoxication model. Copyright © 2007 John Wiley & Sons, Ltd.
Treatment of recurrent pulmonary vein stenoses with endovascular stenting and adjuvant oral sirolimus
Authors: Bromberg‐Marin Guilherme , Tsimikas Sotirios , Mahmud Ehtisham
Published: January 2007

The increasing use of radiofrequency catheter ablation for the cure of atrial fibrillation has led to iatrogenic pulmonary vein stenosis as a new clinical entity. The optimal diagnostic modality and treatment for pulmonary vein stenosis and restenosis remain unclear. We report the successful treatment of pulmonary vein restenosis following percutaneous balloon angioplasty, and for the first time, following surgical bovine pericardial patch angioplasty, with endovascular stenting and adjuvant oral sirolimus. Both patients remain asymptomatic at 1 year follow‐up without evidence of restenosis. © 2006 Wiley‐Liss, Inc.
The Impact of Microtechnologies on Chemical and Pharmaceutical Production Processes
Authors: Pieters B. , Andrieux G. , Eloy J.‐C.
Published: January 2007

Microreaction technology has been developed as a new chemical tool for process intensification. The technology is still at its early stage but has started to succeed its implementation in R&D labs of fine and specialty chemicals companies. This technology has many advantages to drive innovation. It leads to new and high quality products. Fine and speciality chemicals represent a niche market for this technology that could reach about EUR 140 million for microstructured parts but only in 15 to 20 years while implemented for production purpose. The improvement of the technology leading to increased technical and economical benefits will open the way to larger markets like commodity chemicals and energy applications.
High Rate Convergent Synthesis and Deposition of Polyamide Dendrimers using a Continuous‐Flow Microreactor
Authors: Liu S. , Chang C.‐H.
Published: January 2007

Polyamide dendrons and dendrimers have been synthesized using a continuous‐flow microreactor. Furthermore, the synthesized polyamide dendron was deposited onto functionalized glass surface through the formation of amide bond using a facile coupling procedure via a microreactor. The dendron deposition process involved two major steps: the functionalization of the native glass surface using 3‐aminopropyl triethoxysilane, and followed by coupling of the synthesized polyamide dendron with an aminosilanised surface. Compared with the conventional synthesis method, the microreactor provides a comparable yield, selectivity and a considerably faster synthesis rate. Nanostructured polyamide G1 dendron thin films could be deposited using an impinging flux from this microreactor in minutes.
Guest‐Dependent Flexible Coordination Networks with Fluorinated Ligands
Authors: Kasai Kayoko , Fujita Makoto
Published: January 2007

Guest‐dependent flexible coordination networks are formed from 1,4‐bis(4‐pyridylmethyl)tetrafluorobenzene (bpf), 4,4′‐bis(4‐pyridylmethyl)octafluorobiphenyl (bpfb), 2,6‐bis(4‐pyridylmethyl)hexafluoronaphthalene (2,6‐bpfn), and 2,7‐bis(4‐pyridylmethyl)hexafluoronaphthalene (2,7‐bpfn) with Cd(NO3)2 in the presence of various organic compounds. The reaction of bpf affords one‐dimensional cyclic chains, two‐dimensional rhombus grid sheets, and three‐dimensional diamond frameworks with threefold interpenetration. The reaction of bpfb mainly affords two‐dimensional rhombus grid sheets with twofold parallel interpenetration. The reaction of 2,6‐bpfn affords a one‐dimensional ladder and two‐dimensional rhombus grid, twisted grid, and herringbone sheets. The reaction of 2,7‐bpfn affords two‐dimensional rhombus grid sheets and grid sheets with dumbbell‐shaped cavities. This diversity of network topologies is induced by interactions between the guest molecules and the flexible ligand frameworks.
Calcium, dietary, and lifestyle factors in the prevention of colorectal adenomas
Authors: Miller Eric A. , Keku Temitope O. , Satia Jessie A. , Martin Christopher F. , Galanko Joseph A. , Sandler Robert S.
Published: January 2007

BACKGROUND.

Many studies have suggested a role for calcium in reducing the risk of colorectal adenomas and cancer but its effectiveness may be dependent on interactions with other dietary and/or lifestyle factors. We examined the association between calcium and prevalence of adenomas and assessed whether the association was stronger in biologically plausible subgroups.

METHODS.

Cross‐sectional data from 222 cases and 479 adenoma‐free controls who underwent colonoscopies and completed food frequency and lifestyle questionnaires were used in the analyses. Multivariable logistic regression was used to estimate the association between calcium and prevalence of adenomas. Stratified analyses and the likelihood ratio test were used to examine effect modification by various demographic, lifestyle, and behavioral factors.

RESULTS.

Overall, little association was observed comparing total calcium intake of ≥900 mg/day to <500 mg/day (adjusted odds ratio [OR] = 0.85, 95% confidence interval [CI]: 0.53–1.37). However, stronger associations were observed in patients with lower fat intake and in those who regularly (≥15 times/month) took nonsteroidal antiinflammatory drugs (NSAIDs). Specifically, total calcium intake of ≥900 mg/day was associated with a lower prevalence of adenomas among patients with lower fat intake (OR = 0.47, 95% CI: 0.25–0.91) but not among those with higher fat intake (OR = 1.20, 95% CI: 0.61–2.35; P‐value for interaction = .01). For NSAIDs, the associations were OR = 0.37 (95% CI: 0.16–0.86) for regular NSAID users and OR = 1.27 (95% CI: 0.73–2.22) with infrequent or nonuse of NSAIDs, respectively (P = .06).

CONCLUSIONS.

The data suggest that a lower‐fat diet and regular NSAID use may enhance calcium's effectiveness as a colorectal cancer preventive agent. Cancer 2007 © 2007 American Cancer Society.
Micro‐Structured Methane Steam Reformer with Integrated Catalytic Combustor
Authors: Cremers C. , Pelz A. , Stimming U. , Haas‐Santo K. , Görke O. , Pfeifer P. , Schubert K.
Published: January 2007

Experimental results of tests using a micro‐structured steam reformer for hydrogen generation from methane in fuel cell systems are reported. A distinctive feature of this work is the integration of a catalytic combustor into the reactor to deliver the necessary heat to the endothermic steam reforming reaction. The tests are performed under static and dynamic load conditions. The reactor is operated autonomously without external heat supply. The best results are obtained by firing the integrated combustor with a mixture of hydrogen and methane in co‐flow with the reforming reaction. Providing carbon dioxide to the combustor feed in order to simulate the situation of anode off‐gas firing has only minor effects on system performance. Under static load conditions up to 2 / min–1 of hydrogen are produced at high methane conversion rates of about 70%. Start‐up tests show that a stable product composition is obtained in less than 20 s after admission of methane to the reformer. Furthermore, the product composition shows only minor variations with throughput and load changes if heating adjustments are done simultaneously. Overall, the reactor proves to be very suitable for operation in fuel cell systems.
Synthesis, characterization, and solution properties of some new organotellurium compounds based on di(cyclohexylmethyl)telluride
Authors: Al‐Rubaie Ali Z. , Al‐Derawi Ala'a K.
Published: January 2007

A new series of organotellurium(IV) compounds based on di(cyclohexylmethyl)telluride (1) (i.e., (C6H11CH2)2TeX2 and (C6H11CH2)2Te(R)X) was prepared by the reaction of compound 1 with halogens, N‐bromosuccinimide, and alkyl halides. Phenylation of (C6H11CH2)2TeX2 with sodium tetraphenylborate gave di(cyclohexylmethyl)phenyltelluronium tetraphenylborate in good yield. Conductivity measurements in dimethylsulfoxide (DMSO) showed a considerable ionic character of these compounds and they behave as 1:1 electrolytes. 1H NMR studies in CDCl3 solution indicated that telluronium salts employed in this study are unstable toward reductive elimination. Reaction of di(cyclohexylmethyl)telluride, (C6H11CH2)2Te(CH3)I, and (C6H11CH2)2Te(PhCH2)Br with HgX2 (X = Cl or Br) afforded 1:1 complexes. All compounds were characterized by elemental analyses and spectroscopic data. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:93–99, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20240
Analysis of processes limiting quantum efficiency of AlGaInN LEDs at high pumping
Authors: Rozhansky I. V. , Zakheim D. A.
Published: January 2007

In this paper we argue that the quenching of external quantum efficiency (EQE) with increase of current typically observed for AlInGaN LEDs is caused by reduction of injection efficiency. It is shown as a result of numerical simulations that the current blocking AlGaN layer is inefficient at high current density due to piezoelectric field of GaN/AlGaN interface. The results of numerical simulation are in good agreement with experimental dependence of EQE on pumping. A new design of LED heterostructure is proposed, for which the EQE quenching is not expected. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rapid identification of C21 steroidal saponins in Cynanchum versicolor Bunge by electrospray ionization multi‐stage tandem mass spectrometry and liquid chromatography/tandem mass spectrometry
Authors: Zheng Zhaoguang , Zhang Weidong , Kong Lingyi , Liang Mingjin , Li Huiliang , Lin Min , Liu Runhui , Zhang Chuan
Published: January 2007

Electrospray ionization multi‐stage tandem mass spectrometry (ESI‐MSn) and liquid chromatography coupled with on‐line electrospray ionization tandem mass spectrometry (LC/ESI‐MSn) were performed to elucidate the clearage rule of nine investigated C21 steroidal saponins and identify them in the saponin fraction of 90% ethanolic extracts from the root and rhizome of Cynanchum versicolor Bunge. The fragments of C21 steroidal saponins in positive and negative ESI‐MSn were used to deduce their mass spectral fragmentation mechanisms, and their structures were further confirmed by ESI‐MSn in positive mode. The MSn spectra of the [M+Na]+ ions for saponins provided a wealth of structural information on glycosidic bond cleavage, which allowed a straightforward interpretation of spectra, with respect to the identifications of features such as the sequences of sugars attached to saponins and sugar type. By using LC/ESI‐MSn, nine C21 steroidal saponins were detected in the saponin fraction of C. versicolor, and an isomer of atratoglaucoside A was elucidated simultaneously. All nine compounds showed an abundant ion for the loss of 46 Da (HCOOH) from [M+Na]+. The losses of monosaccharide sequences and aglycone as neutral fragmentation from [M+Na‐HCOOH]+ were also acquired as the characteristic ions of these C21 steroidal saponins. It provided important information on monosaccharide sequences and in particular on sugar types and could be used to identify and elucidate other C21 steroidal saponins. These studies allowed us to rapidly identify C21 steroidal saponins from Radix cynanchi atrati. It is indicated that the described method had wide applicability to rapidly screen and provide structural confirmation on C21 steroidal saponins in crude materials. Copyright © 2007 John Wiley & Sons, Ltd.
Immuno‐mass spectrometry assay of EPI‐HNE4, a recombinant protein inhibitor of human elastase
Authors: Dubois Mathieu , Becher François , Herbet Amaury , Ezan Eric
Published: January 2007

In order to increase the sensitivity of liquid chromatography/mass spectrometry (LC/MS) assays of recombinant proteins for pharmacokinetics studies, we have developed an immuno‐mass spectrometry assay for EPI‐hNE4, a 6237 Da protein currently developed for respiratory distress syndromes. After immunocapture of the analyte in human plasma with magnetic beads coated with anti‐EPI‐hNE4 antibodies, the intact protein was eluted and separated in reversed‐phase LC and then analysed by tandem mass spectrometry (MS/MS) in selected reaction monitoring (SRM) mode. The problem of analytical interference due to endogenous binding antibodies was addressed by successive steps of acidification and neutralisation before immunocapture. Furthermore, potential variations in the recovery of analyte during sample extraction were compensated for by addition of an internal standard recognised by the antibodies. The precision of the assay remained therefore below 15%. A significant increase in assay sensitivity was achieved since the extraction step allowed sample concentration and removal of matrix components interfering with the electrospray ionisation process. Using 0.4 mL of plasma, a limit of quantification at 0.5 ng/mL (80 pM) was reached, which represents a 10‐fold improvement in sensitivity over our previous work using sample precipitation. This technique was able to monitor EPI‐hNE4 kinetics in the plasma of human subjects for 36 h after an intravenous administration of 0.125 mg/kg. Copyright © 2007 John Wiley & Sons, Ltd.
On the convergence of nonlinear optimal control using pseudospectral methods for feedback linearizable systems
Authors: Kang W. , Gong Q. , Ross I. M. , Fahroo F.
Published: January 2007

We consider the optimal control of feedback linearizable dynamic systems subject to mixed state and control constraints. In contrast to the existing results, the optimal controller addressed in this paper is allowed to be discontinuous. This generalization requires a substantial modification to the existing convergence analysis in terms of both the framework as well as the notion of convergence around points of discontinuity. Although the nonlinear system is assumed to be feedback linearizable, the optimal control does not necessarily linearize the dynamics. Such problems frequently arise in astronautical applications where stringent performance requirements demand optimality over feedback linearizing controls. We prove that a sequence of solutions obtained using the Legendre pseudospectral method converges to the optimal solution of the continuous‐time problem under mild conditions. Published in 2007 by John Wiley & Sons, Ltd.
Motion of large bubbles in curved channels
Authors: MURADOGLU METIN , STONE HOWARD A.
Published: January 2007

We study the motion of large bubbles in curved channels both semi-analytically using the lubrication approximation and computationally using a finite-volume/front-tracking method. The steady film thickness is governed by the classical Landau–Levich–Derjaguin–Bretherton (LLDB) equation in the low-capillary-number limit but with the boundary conditions modified to account for the channel curvature. The lubrication results show that the film is thinner on the inside of a bend than on the outside of a bend. They also indicate that the bubble velocity relative to the average liquid velocity is always larger in a curved channel than that in a corresponding straight channel and increases monotonically with increasing channel curvature. Numerical computations are performed for two-dimensional cases and the computational results are found to be in a good agreement with the lubrication theory for small capillary numbers and small or moderate channel curvatures. For moderate capillary numbers the numerical results for the film thickness, when rescaled to account for channel curvature as suggested in the lubrication calculation, essentially collapse onto the corresponding results for a bubble in a straight tube. The lubrication theory is also extended to the motion of large bubbles in a curved channel of circular cross-section.
Statistical structure of turbulent-boundary-layer velocity–vorticity products at high and low Reynolds numbers
Authors: PRIYADARSHANA P. J. A. , KLEWICKI J. C. , TREAT S. , FOSS J. F.
Published: January 2007

The mean wall-normal gradients of the Reynolds shear stress and the turbulent kinetic energy have direct connections to the transport mechanisms of turbulent-boundary-layer flow. According to the Stokes–Helmholtz decomposition, these gradients can be expressed in terms of velocity–vorticity products. Physical experiments were conducted to explore the statistical properties of some of the relevant velocity–vorticity products. The high-Reynolds-number data (Rθ≃O(106), where θ is the momentum thickness) were acquired in the near neutrally stable atmospheric-surface-layer flow over a salt playa under both smooth- and rough-wall conditions. The low-Rθdata were from a database acquired in a large-scale laboratory facility at 1000 >Rθ> 5000. Corresponding to a companion study of the Reynolds stresses (Priyadarshana & Klewicki,Phys. Fluids, vol. 16, 2004, p. 4586), comparisons of low- and high-Rθas well as smooth- and rough-wall boundary-layer results were made at the approximate wall-normal locationsyp/2 and 2yp, whereypis the wall-normal location of the peak of the Reynolds shear stress, at each Reynolds number. In this paper, the properties of thevωz,wωyanduωzproducts are analysed through their statistics and cospectra over a three-decade variation in Reynolds number. Hereu,vandware the fluctuating streamwise, wall-normal and spanwise velocity components and ωyand ωzare the fluctuating wall-normal and spanwise vorticity components. It is observed thatv–ωzstatistics and spectral behaviours exhibit considerable sensitivity to Reynolds number as well as to wall roughness. More broadly, the correlations between thevand ω fields are seen to arise from a ‘scale selection’ near the peak in the associated vorticity spectra and, in some cases, near the peak in the associated velocity spectra as well.
Two-dimensional simulation of unsteady heat transfer from a circular cylinder in crossflow
Authors: BOUHAIRIE SALEM , CHU VINCENT H.
Published: January 2007

The heat transfer from the surface of a circular cylinder into a crossflow has been computed using a two-dimensional model, for a range of Reynolds numbers fromRe=200 to 15550. The boundary-layer separation, the local and overall heat-transfer rates, the eddy- and flare-detachment frequencies and the width of the flares were determined from the numerical simulations. In this range of Reynolds numbers, the heat-transfer process is unsteady and is characterized by a viscous length scale that is inversely proportional to the square root of the Reynolds number. To ensure uniform numerical accuracy for all Reynolds numbers, the dimensions of the computational mesh were selected in proportion to this viscous length scale. The small scales were resolved by at least three nodes within the boundary layers. The frequency of the heat flares increases, and the width of each flare decreases, with the Reynolds number, in proportion to the viscous time and length scales. Despite the presence of three-dimensional structures for the range of Reynolds numbers considered, the two-dimensional model captures the unsteady processes and produced results that were consistent with the available experimental data. It correctly simulated the overall, the front-stagnation and the back-to-total heat-transfer rates.
The persistence of balance in geophysical flows
Authors: DRITSCHEL DAVID G. , VIÚDEZ ÁLVARO
Published: January 2007

Rotating stably stratified geophysical flows can exhibit a near ‘balanced’ evolution controlled by the conservative advection of a single scalar quantity, the potential vorticity (PV). This occurs frequently in the Earth's atmosphere and oceans where motions tend to be weak compared with the background planetary rotation and where stratification greatly inhibits vertical motion. Under these circumstances, both high-frequency acoustic waves and lower-frequency inertia–gravity waves (IGWs) contribute little to the flow evolution compared with the even-lower-frequency advection of PV. Moreover, this ‘slow’ PV-controlled balanced evolution appears unable to excite these higher-frequency waves in any significant way – i.e. balance persists.

The present work pushes the limits of balance by systematically exploring the evolution of a range of highly nonlinear flows in which motions are comparable with the background rotation. These flows do not possess a frequency separation between PV advection and IGWs. Nonetheless, the flows exhibit a remarkable persistence of balance. Even when flows are not initialized to minimize the amount of IGWs initially present, and indeed even when flows are deliberately seeded with significant IGW amplitudes, the flow evolution – over many inertial periods (days) – remains strongly controlled by PV advection.
Flow structure and variability in the subtropical Indian Ocean: Instability of the South Indian Ocean Countercurrent
Authors: Palastanga V. , van Leeuwen P. J. , Schouten M. W. , de Ruijter W. P. M.
Published: January 2007

The origin of the eddy variability around the 25°S band in the Indian Ocean is investigated. We have found that the surface circulation east of Madagascar shows an anticyclonic subgyre bounded to the south by eastward flow from southwest Madagascar, and to the north by the westward flowing South Equatorial Current (SEC) between 15° and 20°S. The shallow, eastward flowing South Indian Ocean Countercurrent (SICC) extends above the deep reaching, westward flowing SEC to 95°E around the latitude of the high variability band. Applying a two‐layer model reveals that regions of large vertical shear along the SICC‐SEC system are baroclinically unstable. Estimates of the frequencies (3.5–6 times/year) and wavelengths (290–470 km) of the unstable modes are close to observations of the mesoscale variability derived from altimetry data. It is likely then that Rossby wave variability locally generated in the subtropical South Indian Ocean by baroclinic instability is the origin of the eddy variability around 25°S as seen, for example, in satellite altimetry.
Smallest Angiosperm Genomes Found in Lentibulariaceae, with Chromosomes of Bacterial Size
Authors: Greilhuber J. , Borsch T. , Müller K. , Worberg A. , Porembski S. , Barthlott W.
Published: January 2007

Abstract: Nuclear holoploid genome sizes (C‐values) have been estimated to vary about 800‐fold in angiosperms, with the smallest established 1C‐value of 157 Mbp recorded in Arabidopsis thaliana. In the highly specialized carnivorous family Lentibulariaceae now three taxa have been found that exhibit significantly lower values: Genlisea margaretae with 63 Mbp, G. aurea with 64 Mbp, and Utricularia gibba with 88 Mbp. The smallest mitotic anaphase chromatids in G. aurea have 2.1 Mbp and are thus of bacterial size (NB: E. coli has ca. 4 Mbp). Several Utricularia species range somewhat lower than A. thaliana or are similar in genome size. The highest 1C‐value known from species of Lentibulariaceae was found in Genlisea hispidula with 1510 Mbp, and results in about 24‐fold variation for Genlisea and the Lentibulariaceae. Taking into account these new measurements, genome size variation in angiosperms is now almost 2000‐fold. Genlisea and Utricularia are plants with terminal positions in the phylogeny of the eudicots, so that the findings are relevant for the understanding of genome miniaturization. Moreover, the Genlisea‐Utricularia clade exhibits one of the highest mutational rates in several genomic regions in angiosperms, what may be linked to specialized patterns of genome evolution. Ultrasmall genomes have not been found in Pinguicula, which is the sister group of the Genlisea‐Utricularia clade, and which does not show accelerated mutational rates. C‐values in Pinguicula varied only 1.7‐fold from 487 to 829 Mbp.