bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Blood Flow Estimates in Lower-Leg Arteries Predict Cardiovascular Events in Japanese Patients With Type 2 Diabetes With Normal Ankle-Brachial Indexes
Authors: Yoshimura Toru , Suzuki Eiji , Egawa Katsuya , Nishio Yoshihiko , Maegawa Hiroshi , Morikawa Shigehiro , Inubushi Toshiro , Hisatomi Akitaka , Fujimoto Kazuma , Kashiwagi Atsunori
Published: July 2006

OBJECTIVE—To examine the association of baseline measures in lower-leg arteries and conventional cardiovascular risk factors with the incidence of cardiovascular disease (CVD) events in type 2 diabetic patients with normal ankle-brachial indexes (ABIs) (>0.9).

RESEARCH DESIGN AND METHODS—We studied 129 type 2 diabetic patients and 35 age-matched nondiabetic subjects with no apparent CVD consecutively admitted to our hospital. At baseline, total flow volume and resistive index, as an index of vascular resistance, at the popliteal artery was evaluated using gated two-dimensional cine-mode phase-contrast magnetic resonance imaging. Patients were followed 4.8 ± 1.5 years (range 3.0–8.2) or until their first event of CVD.

RESULTS—On follow-up, 16 patients developed primary CVD events. Patients with CVD had lower blood flow (P < 0.01) and higher vascular resistance (P < 0.05) than patients without CVD. When the patients were grouped into tertiles according to their levels of total flow volume (129.6–85.5, 85.3–63.3, and 62.7–23.8 ml/min), Kaplan-Meier analysis showed a higher probability of developing CVD events in patients in the lowest than in patients in the highest (P = 0.0199, log-rank test) tertile. Multivariate Cox proportional hazards analysis revealed that the lowest tertile for flow volume (hazard ratio [HR] 8.60, 95% CI 1.61–45.97, P = 0.012), hypertension (3.99, 1.12–14.25, P = 0.033), and smoking status (12.01, 1.21–119.28, P = 0.034) were significant independent predictors of CVD events.

CONCLUSIONS—We have demonstrated that low blood flow estimates in lower-leg arteries may be predictive for CVD events among Japanese patients with type 2 diabetes even though they have a normal ABI.
Impaired Exercise-Induced Blood Volume in Type 2 Diabetes With or Without Peripheral Arterial Disease Measured by Continuous-Wave Near-Infrared Spectroscopy
Authors: Mohler Emile R. , Lech Gwen , Supple Gregory E. , Wang Hao , Chance Britton
Published: July 2006

OBJECTIVE—Diabetes is a significant risk factor for peripheral arterial disease (PAD) and is associated with accelerated atherosclerosis and limb loss. However, the pathophysiology involved in PAD is unclear. This study was conducted to evaluate the hemodynamic response to exercise of patients with and without diabetes and PAD.

RESEARCH DESIGN AND METHODS—The hemodynamic response in calf muscles of patients with diabetes, PAD, or both was determined using near-infrared spectroscopy (NIRS). Patients performed both a plantar-flexion and treadmill-walking exercise regimen.

RESULTS—Skeletal muscle capillary blood volume expansion during exercise, as measured by NIRS, was significantly impaired in the lower extremities of diabetic patients with a normal ankle-brachial index. The relative deoxygenation and oxygenation recovery times measured by NIRS correlates significantly with the presence of PAD.

CONCLUSIONS—Patients with diabetes have reduced capillary volume expansion even without PAD. This is likely due to impaired vasodilation secondary to endothelial dysfunction. Further studies are needed to determine whether pharmaceutical intervention improves the blood volume expansion in the diabetic state.
Frequency and Temporal Profile of Poststroke Hyperglycemia Using Continuous Glucose Monitoring
Authors: Allport Louise , Baird Tracy , Butcher Ken , MacGregor Lachlan , Prosser Jane , Colman Peter , Davis Stephen
Published: July 2006

OBJECTIVE—Poststroke hyperglycemia (PSH) is common and has adverse effects on outcome. In this observational study, we aimed to describe the frequency and temporal profile of PSH using a continuous glucose monitoring system (CGMS) in patients with and without diabetes.

RESEARCH DESIGN AND METHODS—Fifty-nine patients with acute hemispheric ischemic stroke were prospectively studied with the CGMS, regardless of medication, admission plasma glucose value, and diabetes status. The CGMS records interstitial glucose every 5 min for 72 h.

RESULTS—On admission, 36% of patients had preexisting diabetes. At the earliest analyzed time point of 8 h from stroke onset, 50% of nondiabetic subjects and 100% of diabetic patients were hyperglycemic (≥7 mmol/l). This early-phase hyperglycemia was followed by a decrease in glucose 14–16 h poststroke when only 11% of nondiabetic and 27% of diabetic patients were hyperglycemic. A late hyperglycemic phase 48–88 h poststroke was observed in 27% of nondiabetic and 78% of diabetic patients. Thirty-four percent of nondiabetic and 86% of diabetic patients were hyperglycemic for at least a quarter of the monitoring period. Multivariate regression analysis demonstrated that diabetes, insular cortical ischemia, and increasing age independently predicted higher glucose values.

CONCLUSIONS—Poststroke hyperglycemia is common and prolonged despite treatment based on current guidelines. There are early and late hyperglycemic phases in nondiabetic as well as diabetic patients. Treatment protocols with frequent glucose measurement and intensive glucose-lowering therapy for a minimum of 72 h poststroke need to be evaluated.
Who Is Tested for Diabetic Kidney Disease and Who Initiates Treatment?
Authors: Johnson Susan L. , Tierney Edward F. , Onyemere Kingsley U. , Tseng Chien-Wen , Safford Monica M. , Karter Andrew J. , Ferrara Assiamira , Duru O. Kenrick , Brown Arleen F. , Narayan K.M. Venkat , Thompson Theodore J. , Herman William H.
Published: July 2006

OBJECTIVE—We examined factors associated with screening for albuminuria and initiation of ACE inhibitor or angiotensin receptor blocker (ARB) treatment in diabetic patients.

RESEARCH DESIGN AND METHODS—We conducted surveys and medical record reviews for 5,378 patients participating in a study of diabetes care in managed care at baseline (2000–2001) and follow-up (2002–2003). Factors associated with testing for albuminuria were examined in cross-sectional analysis at baseline. Factors associated with initiating ACE inhibitor/ARB therapy were determined prospectively.

RESULTS—At baseline, 52% of patients not receiving ACE inhibitor/ARB therapy and without known diabetic kidney disease (DKD) were screened for albuminuria. Patients ≥65 years of age, those with higher HbA1c, those with cardiovascular disease (CVD), and those without hyperlipidemia were less likely to be screened. Of the patients with positive screening tests, 47% began ACE inhibitor/ARB therapy. Initiation of therapy was associated with positive screening test results, BMI ≥25 kg/m2, treatment with insulin or oral antidiabetic agents, peripheral neuropathy, systolic blood pressure ≥140 mmHg, and CVD. Of the patients receiving ACE inhibitor/ARB therapy or with known DKD, 63% were tested for albuminuria.

CONCLUSIONS—Screening for albuminuria was inadequate, especially in older patients or those with competing medical concerns. The value of screening could be increased if more patients with positive screening tests initiated ACE inhibitor/ARB therapy. The efficiency of screening could be improved by limiting screening to diabetic patients not receiving ACE inhibitor/ARB therapy and without known DKD.
Deficiencies of Cardiovascular Risk Prediction Models for Type 1 Diabetes
Authors: Zgibor Janice C. , Piatt Gretchen A. , Ruppert Kristine , Orchard Trevor J. , Roberts Mark S.
Published: July 2006

OBJECTIVE—Cardiovascular risk prediction models are available for the general population (Framingham) and for type 2 diabetes (U.K. Prospective Diabetes Study [UKPDS] Risk Engine) but may not be appropriate in type 1 diabetes, as risk factors including younger age at diabetes onset and presence of diabetes complications are not considered. Therefore, our objective was to examine the accuracy of Framingham and UKPDS models for predicting coronary heart disease (CHD) in a type 1 diabetic cohort.

RESEARCH DESIGN AND METHODS—Ten-year follow-up data from the Pittsburgh Epidemiology of Diabetes Complications (EDC) study, a prospective cohort study of 658 subjects with childhood-onset type 1 diabetes diagnosed between 1950 and 1980 first seen in 1986–1988, were analyzed. EDC study data were used to calculate the 10-year probability of CHD (fatal CHD, nonfatal myocardial infarction, or Q-waves) applying to the Framingham and UKPDS equations.

RESULTS—Mean age at CHD onset was 39 years. When fatal/nonfatal myocardial infarction and CHD death were modeled, both the UKPDS and Framingham models showed significant lack of calibration (P < 0.0001) but moderate discrimination (0.76 UKPDS, 0.77 Framingham men, and 0.88 Framingham women). Both the UKPDS and Framingham models underestimated probability of events in highest risk deciles.

CONCLUSIONS—Currently available CHD models poorly predict events in type 1 diabetes. Future research should focus on determining the risk factors accounting for the lack of fit and developing prediction models specific to this high-risk group.
Association Between Serum Ferritin, Hemoglobin, Iron Intake, and Diabetes in Adults in Jiangsu, China
Authors: Shi Zumin , Hu Xiaoshu , Yuan Baojun , Pan Xiaoqun , Meyer Haakon E. , Holmboe-Ottesen Gerd
Published: July 2006

OBJECTIVE—To investigate the association between iron status, iron intake, and diabetes among Chinese adults.

RESEARCH DESIGN AND METHODS—This cross-sectional household survey was carried out in 2002 in Jiangsu Province, China. The sample contained 2,849 men and women aged ≥20 years with a response rate of 89.0%. Iron intake was assessed by food weighing plus consecutive individual 3-day food records. Fasting plasma glucose (FPG), serum ferritin, and hemoglobin were measured.

RESULTS—The prevalence of anemia was 18.3% in men and 31.5% in women. Mean hemoglobin and serum ferritin increased across groups with increasing FPG. The prevalence of anemia among women was 15.0% in individuals with FPG >7.0 mmol/l compared with 32.6% in individuals with FPG <5.6 mmol/l. There was a similar, however not significant, trend among men. In women, after adjusting for known risk factors, the odds ratio (OR) of diabetes was 2.15 (95% CI 1.03–4.51) for subjects in the upper quartile of hemoglobin compared with the rest, and the corresponding OR for the upper quartile of serum ferritin was 3.79 (1.72–8.36). Iron intake was positively associated with diabetes in women; fourth quartile intake of iron yielded an OR of 5.53 (1.47–20.44) compared with the first quartile in the multivariate analyses. In men, similar trends were suggested, although they were not statistically significant.

CONCLUSIONS—Iron status and iron intake was independently associated with risk of diabetes in Chinese women but not in men.
Influence of Hepatic Steatosis (Fatty Liver) on Severity and Composition of Dyslipidemia in Type 2 Diabetes
Authors: Toledo Frederico G.S. , Sniderman Allan D. , Kelley David E.
Published: July 2006

OBJECTIVE—The objective of this study was to examine the associations between the severity of hepatic steatosis and dyslipidemia in type 2 diabetes, including circulating apolipoprotein B100 (apoB) concentrations and lipoprotein particle size and numbers.

RESEARCH DESIGN AND METHODS—Computed tomography imaging was used to assess hepatic fat content and adipose tissue distribution in 67 men and women with type 2 diabetes, withdrawn from antidiabetic medications preceding the study. Fasting serum lipoprotein number and size was determined by nuclear magnetic resonance. Insulin sensitivity was measured with a glucose clamp and a [6,6-2H2]glucose isotope infusion.

RESULTS—Two-thirds of the cohort had fatty liver. Hepatic steatosis correlated with serum triglycerides (r = 0.40, P < 0.01) and lower HDL cholesterol (r = −0.31, P < 0.05). ApoB and LDL cholesterol did not, being virtually identical in those with or without steatosis. The association between serum triglycerides and hepatic steatosis was largely accounted for by greater triglyceride enrichment in VLDL particles, which were larger. Severe steatosis was also associated with 70% higher small, dense LDL concentrations. Visceral obesity did not fully explain these associations, and hepatic steatosis was better correlated with triglycerides than with hyperglycemia or hepatic insulin resistance (P > 0.05).

CONCLUSIONS—The presence of hepatic steatosis in type 2 diabetes does not appear to affect apoB levels, but potentially increases atherogenesis by increasing triglycerides, reducing HDL levels, and increasing small, dense LDL.
Impaired Insulin Secretion After Prenatal Exposure to the Dutch Famine
Authors: de Rooij Susanne R. , Painter Rebecca C. , Phillips David I.W. , Osmond Clive , Michels Robert P.J. , Godsland Ian F. , Bossuyt Patrick M.M. , Bleker Otto P. , Roseboom Tessa J.
Published: July 2006

OBJECTIVE—We previously reported that people prenatally exposed to famine during the Dutch Hunger Winter of 1944–1945 have higher 2-h glucose concentrations after an oral glucose tolerance test in later life. We aimed to determine whether this association is mediated through alterations in insulin secretion, insulin sensitivity, or a combination of both.

RESEARCH DESIGN AND METHODS—We performed a 15-sample intravenous glucose tolerance test in a subsample of 94 normoglycemic men and women from the Dutch Famine Birth Cohort. We used the disposition index, derived as the product of insulin sensitivity and the first-phase insulin response to glucose as a measure of the activity of the β-cells adjusted for insulin resistance. In all analyses, we adjusted for sex and BMI.

RESULTS—Glucose tolerance was impaired in people who had been prenatally exposed to famine compared with people unexposed to famine (difference in intravenous glucose tolerance test Kg value −21% [95% CI −41 to −4]). People exposed to famine during midgestation had a significantly lower disposition index (−53% [−126 to −3]) compared with people unexposed to famine. Prenatal exposure to famine during early gestation was also associated with a lower disposition index, but this difference did not reach statistical significance.

CONCLUSIONS—Impaired glucose tolerance after exposure to famine during mid-gestation and early gestation seems to be mediated through an insulin secretion defect.
Cognitive Dysfunction Is Associated With Poor Diabetes Control in Older Adults
Authors: Munshi Medha , Grande Laura , Hayes Mellody , Ayres Darlene , Suhl Emmy , Capelson Roberta , Lin Susan , Milberg William , Weinger Katie
Published: July 2006

OBJECTIVE—To evaluate the association between cognitive dysfunction and other barriers and glycemic control in older adults with diabetes.

RESEARCH DESIGN AND METHODS—Patients over the age of 70 years presenting to a geriatric diabetes clinic were evaluated for barriers to successful diabetes management. Patients were screened for cognitive dysfunction with the Mini Mental State Examination (MMSE) and a clock-drawing test (CDT) scored by 1) a method validated by Mendez et al. and 2) a modified CDT (clock in a box [CIB]). Depression was evaluated with the Geriatric Depression Scale. Interview questionnaires surveyed activities of daily living (ADLs) and instrumental ADLs (IADLs), as well as other functional disabilities.

RESULTS—Sixty patients (age 79 ± 5 years, diabetes duration 14 ± 13 years) were evaluated. Thirty-four percent of patients had low CIB (≤5), and 38% of patients had low CDT (≤13). Both CIB as well as CDT were inversely correlated with HbA1c, suggesting that cognitive dysfunction is associated with poor glycemic control (r = −0.37, P < 0.004 and r = −0.38, P < 0.004, respectively). Thirty-three percent of patients had depressive symptoms with greater difficulty completing the tasks of the IADL survey (5.7 ± 1.7 vs. 4.6 ± 2.0; P < 0.03). These older adults with diabetes had a high incidence of functional disabilities, including hearing impairment (48%), vision impairment (53%), history of recent falls (33%), fear of falls (44%), and difficulty performing IADLs (39%).

CONCLUSIONS—Older adults with diabetes have a high risk of undiagnosed cognitive dysfunction, depression, and functional disabilities. Cognitive dysfunction in this population is associated with poor diabetes control.
Conformational studies of aliphatic secondary ozonides (propene, 1-butene and 1-heptene) by means of FTIR spectroscopy
Authors: Bariseviciute Ruta , Ceponkus Justinas , Gruodis Alytis , Sablinskas Valdas
Published: July 2006

Ozonization reaction of simple alkenes was studied by means of FT infrared absorption gas spectroscopy. The reaction was performed at 95 K in neat films of the reactants. IR absorption spectra of the gaseous products were recorded. The spectra were analyzed combining experimental results with theoretical calculations performed at B3LYP 6-311++G (3df, 3pd) level. We found that among all theoretically predicted conformers of propene secondary ozonide, only one which has the O-O half-chair configuration for the five membered ring and the radical attached in the equatorial position was present in the sample. Samples of 1-butene and 1-heptene secondary ozonides consist from two conformers of very similar energy (ΔH=0.3 kJ/mol). The most stable conformer for both ozonides is the one with O-O half-chair configuration of the five membered ring and the radical attached in equatorial position and the aliphatic chain in gauche position. The second stable conformer has the aliphatic chain in anti position.
Schistosoma japonicum: The design and experimental evaluation of a multivalent DNA vaccine
Authors: Li Chunyan , Yu Longjiang , Liu Zhi , Zhu Lu , Hu Yuan , Zhu Min , Zhu Xiaohua , Shi Youen , Meng Sijin
Published: July 2006

The aim of this study was to construct and evaluate the immunity efficacy of the DNA multivalent vaccine pVIVO2SjFABP-23. The vaccine was constructed and produced as follows. Forty BALB/c mice were divided into four groups designated pVIVO2, pVIVO2Sj23, pVIVO2SjFABP and pVIVO2SjFABP-23. Each mouse was immunized with 100 μg of the corresponding plasmid DNA by intramuscular injection. 28 days post-vaccination, the mice were challenged with S. japonicum cercariae, and the worm and egg burdens were determined 42 days post-challenge. Serum samples were collected from all the mice before and after vaccination and at the end of the experiment, and used for antibody detection. The IFN-γ and IL-4 levels were quantified in the supernatants of specifically stimulated spleen cells. The number of worms was reduced by 52%, 40% and 42% in mice respectively immunized with pVIVO2SjFABP-23, pVIVO2Sj23 or pVIVO2SjFABP. A respective 61%, 38% and 39% egg reduction was determined relative to those mice that only received the empty pVIVO2 plasmid. pVIVO2SjFABP-23 immunization increased IgG levels against SWAP and SEA. Increased IFN-γ levels were detected in the supernatant of specific stimulated spleen cells from mice immunized with the 3 different constructs. The multivalent DNA vaccine developed induced higher levels of protection than the two monovalent tested vaccines.
Emulsions of oil from Adenanthera pavonina L. seeds and their protective effect
Authors: Jaromin Anna , Żarnowski Robert , Kozubek Arkadiusz
Published: July 2006

In our previous study, we developed very stable formulations of submicron oil-in-water emulsions from Adenanthera pavonina L. (family Leguminosae, subfamily Mimosoideae) seed oil, stabilised with soybean lecithin (SPC). Continuing our research, we introduced an additional co-emulsifier, Tween 80, to those formulations in order to decrease the size of the emulsion particles and improve their stability. Formulations with a mean particle size ranging from 43.6 to 306.5 nm and a negative surface charge from −45.3 to −28.5 mV were obtained. Our stability experiments also revealed that most of the tested formulations had a very good degree of stability over a 3-month storage period, both at 4°C and at room temperature.

Since many intravenous injectable drugs exhibit lytic activity against erythrocytes, we examined this activity for the emulsion form of cardol, a natural compound with already proven hemolytic properties. The incorporation of this agent into the emulsion caused an evident decrease in hemolytic activity (97–99%). This highly protective effect, observed against sheep erythrocytes, was independent of both the composition and the particle size of the emulsions used. Our studies suggest that nonionic surfactant/phospholipid-based emulsions containing this edible oil of A. pavonina L. may be useful as an alternative formulation matrix for pharmaceutical, nutritional or cosmetic applications of otherwise membrane-acting components.
Organizing a Ground Crew for Today's Helicopter Parents
Authors: Coburn Karen Levin
Published: July 2006

The relationship between college students and their parents is far closer than it was when most of today's educators were in school. Tapping into the upside and managing the potential drawbacks of highly involved parents is taking on great importance on an increasing number of campuses.
The Home of the Brave
Authors: Klein Thomas
Published: July 2006

Whereas some faculty members at the end of their careers choose the tidy comfort of the stand-alone classroom, Thomas Klein chose the rich and raw life of a residential learning community teacher. Poignant moments from his experience may offer inspiration to other courageous educators.
Training conditional and cumulative risk judgements: the role of frequencies, problem‐structure and einstellung
Authors: McCloy Rachel , Beaman C. Philip , Morgan Beth , Speed Rebecca
Published: July 2006

Two experiments implement and evaluate a training scheme for learning to apply frequency formats to probability judgements couched in terms of percentages. Results indicate that both conditional and cumulative probability judgements can be improved in this manner, however the scheme is insufficient to promote any deeper understanding of the problem structure. In both experiments, training on one problem type only (either conditional or cumulative risk judgements) resulted in an inappropriate transfer of a learned method at test. The obstacles facing a frequency‐based training programme for teaching appropriate use of probability data are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Three-year results of a randomized clinical trial of lightweight or standard polypropylene mesh in Lichtenstein repair of primary inguinal hernia
Authors: Bringman S , Wollert S , Österberg J , Smedberg S , Granlund H , Heikkinen T-J
Published: July 2006

Background

This randomized trial examined whether lightweight (LW) polypropylene mesh (large pore size, partially absorbable) could have long-term benefits in reducing chronic pain and inflammation after inguinal hernia repair.

Methods

Six hundred men with a primary unilateral inguinal hernia were randomized to Lichtenstein repair using a standard polypropylene mesh or a LW mesh in one of six centres. The patients were blinded to which mesh they received. Clinical examination was performed and a pain questionnaire completed 3 years after surgery.

Results

Of the 590 men who had surgery, 243 (82·7 per cent) of 294 in the standard mesh group and 251 (84·8 per cent) of 296 in the LW mesh group were examined in the clinic, a median of 37 (range 30-48) months after hernia repair. There were nine recurrent hernias in each group (3·7 per cent with standard mesh and 3·6 per cent with LW mesh). Patients who had LW mesh had less pain on examination, less pain on rising from lying to sitting, fewer miscellaneous groin problems and felt the mesh less often than patients with standard mesh.

Conclusion

Use of LW mesh for Lichtenstein hernia repair did not affect recurrence rates, but improved some aspects of pain and discomfort 3 years after surgery.
Proximal loop jejunostomy is a useful adjunct in the management of multiple intestinal suture lines in the septic abdomen
Authors: Shetty V , Teubner A , Morrison K , Scott N A
Published: July 2006

Background

Bowel repair in the septic abdomen can be problematic. This study investigated the use of a proximal loop jejunostomy to protect injured or fistulated bowel that had been returned to the abdomen after repair and/or anastomosis.

Methods

Ten patients who underwent laparotomy for intra-abdominal sepsis and/or fistulation, followed by distal enteric repair and/or anastomosis and construction of a proximal defunctioning loop jejunostomy, were studied retrospectively. Seven patients had 21 intestinal suture lines returned to the peritoneal cavity in the presence of intra-abdominal sepsis (14 anastomoses, two enterotomy closures and five serotomy repairs). Two patients had a difficult relaparotomy for pelvic abscess (two distal anastomoses, one enterotomy closure and three serotomy repairs). The final patient had pelvic sepsis and radiation enteritis; the distal anastomosis was defunctioned by a loop jejunostomy.

Results

The median distance from the duodenojejunal flexure to the loop stoma was 80 (range 30–170) cm. All jejunostomies were closed via a local approach, a median of 11 (range 9–18) months after formation. There was no significant postoperative morbidity and no postoperative death. At a median follow-up of 7 (range 0·5–56) months eight patients had no requirement for nutritional support.

Conclusion

Use of a loop jejunostomy to protect suture lines in the septic abdomen justifies consideration of this procedure in selected patients.
Molecular Pair Analysis: CH⋅⋅⋅F Interactions in the Crystal Structure of Fluorobenzene? And Related Matters
Authors: Dunitz Jack. D. , Schweizer W. Bernd
Published: July 2006

The crystal structure of fluorobenzene is compared with isomorphous crystal structures of molecules of roughly similar shape. The lowest‐energy fluorobenzene dimers are identified by theoretical calculations. Molecular pair analysis of the crystal structure of fluorobenzene and of an isomorphous virtual low‐energy polymorph of benzene suggests that the important intermolecular interactions in the two structures are closely similar. In particular, the intermolecular CH⋅⋅⋅F interactions in the fluorobenzene crystal have approximately the same structure‐directing ability and influence on the intermolecular energy as the corresponding CH⋅⋅⋅H interactions in benzene. Molecular pair analysis of the isomorphous crystal structures of benzonitrile, alloxan, and cyclopentene‐1,2,3‐trione indicates that essentially the same crystal structure can be adopted with quite different patterns of pair energies and atom–atom interactions. The question as to whether the packing radius of organic fluorine is larger or smaller than that of hydrogen, is addressed, but not answered.
From Supramolecular Porphyrin Tweezers to Dynamic AnBmClDk Multiporphyrin Arrangements Through Orthogonal Coordination
Authors: Kishore Ravuri S. K. , Paululat Thomas , Schmittel Michael
Published: July 2006

A dynamic, supramolecular, three‐component AnBmCl bis(zinc porphyrin) tweezer has been prepared quantitatively using the heteroleptic bisphenanthroline (HETPHEN) concept. Upon addition of nitrogenous spacers of different length, namely, the extended bipyridine 3 a, 4,4′‐bipyridine (3 b), and 1,4‐diazabicyclo[2.2.2]octane (DABCO; 3 c), to set up an additional orthogonal binding motif (ZnPor–Nspacer), three structurally different, still dynamic, four‐component AnBmClDk assemblies were cleanly formed, as indicated by UV/Vis and NMR titrations as well as by DOSY investigations. The structures were identified as a bridged monotweezer A2BC2D, a doubly bridged double tweezer A4B2C4D2, and a triply bridged double tweezer A4B2C4D3, the latter resembling a porphyrin stack. Notably, the same structures were equally formed directly from a mixture of the constituents A, B, C, and D put together in any sequence if the correct stoichiometry was applied.
Examining the use of subsidies for the abatement of greenhouse gas emissions through experimental simulations
Authors: Olsson Lars E. , Akiyama Manabu , Gärling Tommy , Gustafsson Mathias , Loukopoulos Peter
Published: July 2006

A market experiment was designed to empirically investigate the potential effectiveness of a governmental subsidy system to reduce sales and therefore production of environmentally harmful products. The important issue of whether the subsidy system preserves competitiveness was also examined. In the experiment two levels of a subsidy for unsold units were compared with no subsidy. To simulate the way in which subsidy levels may vary across time in real markets, the effects of high and low uncertainty regarding the subsidy level were also investigated. The results showed that subsidies, whether known and fixed or uncertain and varying, did not erode competition but nevertheless led to higher prices, which resulted in fewer sales. In the control condition a price war resulting in decreasing prices and increasing sales were observed. Several ways in which the proposed subsidy system may be implemented in the transport sector and other sectors are discussed. It is suggested that subsidies may make the adjustment process toward sustainable production less costly for the regulated parties. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
In situ HT‐XRD Study on the Formation of Hexagonal Ammonium Tungsten Bronze by Partial Reduction of Ammonium Paratungstate Tetrahydrate
Authors: Szilágyi Imre Miklós , Hange Ferenc , Madarász János , Pokol György
Published: July 2006

Hexagonal ammonium tungsten bronze, (NH4)0.33–xWO3–y, is a possible constituent of the intermediate “tungsten blue oxide” in non‐sag (NS) tungsten production and a material of chromogenic and sensor interest. Its formation has been studied by in situ high‐temperature powder X‐ray diffraction (HT‐XRD) accompanied by semiquantitative phase analysis through the partial thermal reduction of ammonium paratungstate tetrahydrate, (NH4)10[H2W12O42]·4H2O, in flowing 10 % H2/He. The effect of the heating program on the formation of the title compound has been discussed. Highly crystalline, monophasic hexagonal ammonium tungsten bronze prepared by partial reduction of ammonium paratungstate tetrahydrate has been characterised by high‐precision powder XRD, X‐ray photoelectron spectroscopy (XPS), chemical analysis and solid‐state 1H NMR spectroscopy (1H‐MAS‐NMR). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Crystal Structure of the VV Dimer [V2O2(μ‐O)(dmpp)2(OCH3)2] and Its Equilibrium with the VV Trimer [V3O3(μ‐O)3(dmpp)3(H2O)](H2O)2 in Methanol/Water Solutions
Authors: Avecilla Fernando , Geraldes Carlos F. G. C. , Macedo Anjos L. , Castro M. Margarida C. A.
Published: July 2006

The behaviour of the cyclic trimeric VV complex [V3O3(μ‐O)3(dmpp)3(H2O)](H2O)2, V3L3, (L = Hdmpp = 3‐hydroxy‐1,2‐dimethyl‐4‐pyridinone) was studied in methanol and methanol/water solutions by using 51V and 1D‐ and 2D 1H NMR spectroscopy. Red crystals, isolated from a highly concentrated methanol solution of the trimeric complex, were analysed by X‐ray crystallography. The solid‐state structure of the compound showed the presence of a new dinuclear VV cluster and allowed for its formulation as a [V2O2(μ‐O)(dmpp)2(OCH3)2] complex, V2Y2L2 (Y = OCH3). This complex crystallises in the monoclinic system: P21/c, a = 8.4573(11) Å, b = 15.034(2) Å and c = 15.849(2) Å, β = 105.300(2)°, V = 1943,7(4) Å3, Z = 2, and R1(wR2) = 0.0492(0.1706). The trimer V3L3 complex dissolved in a dry methanol solution fully decomposes, as shown by the 51V NMR signals at –388, –450 and –551 ppm, which are assigned to a monomer complex [VO(OMe)(dmpp)2] (VYL2), the dimer V2Y2L2 and the monomethyl ester of monovanadate, V1Y (V1 = monovanadate; Y = OCH3), respectively. In methanol/water solutions, a new 51V NMR signal appears at δ = –492 ppm, which is assigned to the [VO2(dmpp)(H2O)2] (VL) complex. When the percentage of water in the mixture increases, the relative intensities of the V2Y2L2 and V1Y signals decrease sharply, and a broad signal at –488 ppm appears, corresponding to the original VV trimer complex, which is the only species present in 94 % water. A temperature‐dependent 1H NMR study of a CD3OD solution of V3L3 confirmed the presence, at room temperature, of the dinuclear V2L2 complex and the VL2 species. At temperatures below 0 °C down to –50 °C, the appearance of new signals reflects the presence of isomers for the V2Y2L2 and VYL2 species with different stabilities and symmetries. 2D 1H homonuclear NMR exchange experiments (EXSY) allowed us to establish the isomeric equilibria that take place in solution, and indicates intramolecular exchange between the two ligands of the major isomer of VYL2 and intermolecular exchange between the major and minor isomers of species of different nuclearity, V2Y2L2 and VYL2. However, no evidence was found for intermolecular exchange between the major isomers and between the minor isomers of species of different nuclearity or between isomers of species of the same nuclearity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
On the Fate of Vanadate in Human Blood
Authors: Gorzsás András , Andersson Ingegärd , Pettersson Lage
Published: July 2006

As a summary of recent activities at our research group, a model describing the distribution of pentavalent vanadium (referred to as vanadate throughout the present work) in human blood has been constructed based on our speciation studies performed in the physiological medium of 0.150 M Na(Cl) with various blood constituents. In addition, other data (most notably with the high mass serum constituents albumin and transferrin) have also been used to give as broad a view as possible. Two antidiabetic drug candidate ligands, picolinate and maltol, have also been included in order to investigate the stability of their vanadium complexes in the presence of blood constituents, i.e. to account for ligand‐exchange possibilities. The model predicts transferrin to be the major carrier of vanadium in the bloodstream. It is capable of almost completely replacing the vanadium‐bound picolinate even if the latter is in large excess. Maltol, on the other hand, can retain most of the vanadium when it is supplied in about a 5 mM concentration. The model still has certain limitations but it serves as a useful base for investigating structure, stability, relationship effects and provides insight into the fate of vanadate in human blood.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Actinide‐Transition Metal Heteronuclear Ions and Their Oxides: {IrUO}+ as an Analogue to Uranyl
Authors: Santos Marta , Marçalo Joaquim , Pires de Matos António , Gibson John K. , Haire Richard G.
Published: July 2006

Recent theoretical calculations have shown that Ir should behave as a chemical analogue to N, with the result that IrUO+, like known NUO+, is predicted to be a stable species isoelectronic with UO22+, the uranyl dication. The target heterometallic analogue to uranyl has now been prepared by direct laser desorption/ionization of a U/Ir alloy, and by oxidation of UIr+ with N2O and C2H4O. Properties of UIr+, UPt+, and UAu+ bimetallic ions have been studied. They demonstrate direct actinide–transition metal bonding, and support the concept of “autogenic isolobality”. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Thermal Rearrangements of Heteroatom‐Bridged Diallenes
Authors: Bui Binh H. , Schreiner Peter R.
Published: July 2006

A systematic application of the BLYP/6‐311+G*//BLYP/6‐31G* computational scheme was utilized to identify the favored aromatic 2,6‐reactions leading to the formally aromatic hetero‐3,4‐dimethylenecyclopentadienediyl derivatives from the thermal rearrangements of (hetero)atom‐bridged diallenes (X = CH–, NH, O, S). Protonation of the heteroatom substituent raises the respective 2,6‐cyclization energybarrier, and the alternative 1,6‐cyclization reaction forming the hetero‐cyclohexadienediyl can compete.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Enantioselective aptameric molecular recognition material: Design of a novel chiral stationary phase for enantioseparation of a series of chiral herbicides by capillary electrochromatography
Authors: André Claire , Berthelot Alain , Thomassin Mireille , Guillaume Yves‐Claude
Published: July 2006

A chiral stationary phase derived from an L‐RNA aptamer is evaluated for the enantiomer separation of a series of herbicide molecules (aryloxypropionic, aryloxyphenoxypropionic, and aminopropionic acid) by CEC after binding to biotin and grafting upon streptavidin‐modified porous glass beads. We demonstrated that the aptamer capillary was stable in term of efficiency and retention during a long period. The influences of the mobile phase constitution and its flow‐velocity on the enantioseparation were also investigated. The results suggest that the interactions of the enantiomer during CEC are solely based on chromatographic mechanisms and that the electrophoresis plays only a minor role. The separation efficiency and peak shape could be improved by Mg2+ divalent cation that stabilized the aptamer secondary structure and thus enhanced the mass transfer kinetics during the ligand‐aptamer binding process. In addition, it was demonstrated that the determination of the enantiomerization barrier of flamprop was possible using this chiral stationary phase.
In‐capillary solid‐phase extraction–capillary electrophoresis for the determination of chlorophenols in water
Authors: Zhang Luo‐Hong , Zhang Cheng‐Jie , Chen Xueming , Feng Yu‐Qi , Wu Xing‐Zheng
Published: July 2006

A novel CE method combined with SPE in a single capillary was developed for analysis of chlorophenols in water. A frit of 0.5 mm was first made by a sol‐gel method, followed by packing a SPE sorbent in the inlet end of the capillary. Two phenol derivatives, 2,4‐dichlorophenol and 2,4,5‐trichlorophenol, were used as the model compounds. By loading sample solutions into the capillary, the two chlorophenols were extracted into the sorbent. They were desorbed by injecting only about 4 nL of methanol. Finally, the analytes were separated by conventional CE. The technique provided a concentration enhancement factor of over 4000‐fold for both chlorophenols. The detection limits (S/N = 3) of 2,4‐dichlorophenol and 2,4,5‐trichlorophenol were determined to be 0.1 ng/mL and 0.07 ng/mL, respectively. For replicate analyses of 5 ng/mL of 2,4‐dichlorophenol, within‐day and between‐day RSDs of migration time, peak height and peak area were in the range of 1.8–2.0%, 4.0–4.4% and 4.1–4.6%, respectively. The method shows wide linear range, acceptable reproducibility and excellent sensitivity, and it was applied to the analyses of spiked river water samples. The capillary packed with the SPE sorbents can be used for more than 400 runs without performance deterioration.
Evidence for freeze–thaw events and their implications for rock weathering in northern Canada: II. The temperature at which water freezes in rock
Authors: Hall Kevin
Published: July 2006

Many undertakings have used either a single value or a narrow window of temperatures as a threshold for the freezing of water within rock. These temperatures vary from 0 to −5 C, with most windows being in the range −1 to −4 C. Based on thermal data, these thresholds are commonly used to ‘count’ the number of freeze–thaw events as a basis for determining freeze–thaw weathering. Data collected from northern Canada indicate that the temperature at which freezing occurs can vary substantially, even for the same site. Using exotherm and zero curtain observations from bricks, at angles of 90 and 45, aligned to the four cardinal aspects, the various temperatures at which water froze are shown. Bricks on the north and east commonly did exhibit freezing, based on exotherms, within the window −1 to −5 C, while data for the south and west aspects showed substantial variation, with freezes sometimes between −6·4 and −8·9 C. The data were evaluated for evidence of zero curtain effects (indicative of water freezing), but no unequivocal events could be found, and it is suggested that, at the scale of observation used here, they are unlikely. It would therefore appear that the use of thermal thresholds may not be meaningful for evaluation of freeze–thaw events. The available data also indicate many instances when temperatures went substantially sub‐zero (e.g. −20 C) and yet no indication of water freezing occurred – most likely because there was no water available to freeze. This indicates that any form of freeze–thaw event counting, in the absence of some indicator of the presence of water and that it actually froze, is flawed, as thermal conditions alone are not adequate to indicate the occurrence or not of actual freeze–thaw weathering events. These data suggest that evaluations of freeze–thaw occurrence based simply on thermal thresholds may be substantially in error. Copyright © 2006 John Wiley & Sons, Ltd.
Export of organic carbon in run‐off from an Amazonian rainforest blackwater catchment
Authors: Waterloo Maarten J. , Oliveira Sylvia M. , Drucker Debora P. , Nobre Antonio D. , Cuartas Luz A. , Hodnett Martin G. , Langedijk Ivar , Jans Wilma W. P. , Tomasella Javier , de Araújo Alessandro C. , Pimentel Tania P. , Múnera Estrada Juan C.
Published: July 2006

Rainfall, run‐off and dissolved and particulate organic carbon concentrations were measured to investigate the hydrological export of organic carbon out of the blackwater Igarapé Asu rainforest catchment over a two‐year period. Annual rainfall was above average (2442 mm) at 2976 mm in 2002 and below average at 2054 mm in 2003. Surface run‐off dominated the flow out of the catchment, with groundwater outflow being negligible. Streamflow totals amounted to 1362 mm in 2002 and 780 mm in 2003. Dissolved organic carbon (DOC) concentrations in rainfall were similar to those measured in rainfall elsewhere in the Amazon Basin at 1·2 mg l−1, leading to atmospheric DOC deposition estimates of 3·5 g m−2 in 2002 and 2·4 g m−2 in 2003. Daily average DOC concentrations in run‐off ranged from 8 mg l−1 under low flow conditions to 27 mg l−1 during large quickflow events. Suspended sediment (10–2000‐µm size fraction) consisted for 28% of carbon and had a median concentration of 4·1 mg l−1. Daily run‐off varied between 1·2–2·5 mm day−1 during dry periods with corresponding organic carbon exports of 0·009–0·031 g m−2 day−1. Exports associated with large storms were much higher, reaching a daily maximum of 1·02 g m−2 day−1 for a discharge event of 38·4 mm. Export of carbon during the wet seasons amounted to 70% of the total. Annual exports in river water were different between the years because of differences in run‐off, varying between 26·2 g C m−2 in 2002 and 11·7 g C m−2 in 2003. Organic carbon exports were dominated by DOC, with exports in sediment constituting 6–8% of the total. Net carbon export, corrected for rainfall inputs, amounted to 22·7 and 9·3 g m−2 in 2002 and 2003, respectively. The present study indicates that accounting for exports of organic carbon in stream run‐off (averaging 19·0 g m−2 year−1 over the 2 years) would reduce the rainforest sink strength, estimated at 300–400 g m−2 year−1 from eddy covariance measurements, by 5–6% for this blackwater catchment. Copyright © 2006 John Wiley & Sons, Ltd.
Organic carbon fluxes within and streamwater exports from headwater catchments in the southern Amazon
Authors: Johnson Mark S. , Lehmann Johannes , Selva Evandro Carlos , Abdo Mara , Riha Susan , Couto Eduardo Guimarães
Published: July 2006

Forms and quantities of organic carbon (C) fluxes at the soil surface, and organic C exports from four small (1–2 ha) headwater catchments were quantified and contrasted in the seasonally dry southern Amazon for 1 year to compare C fluxes within the terrestrial ecosystem with exports to the aquatic ecosystem. At the soil surface, the flux of litterfall C was 43 times greater than the dissolved organic carbon (DOC) flux in throughfall, with the highest rates of C deposition during the dry season. The form and timing of organic C was reversed for watershed exports, where DOC comprised 59% of the annual total organic C export, and exports were greatest during the 4‐month rainy season (63% of total annual exports). Fine particulate organic carbon (FPOC) in streamwater was a substantially larger flux than coarse particulate organic carbon (CPOC), representing 37 and 4% of total annual organic C exports, respectively. Particulate organic C exports exhibited substantial seasonal variability, with FPOC and CPOC mobilized primarily in the rainy season and strongly connected to storm events. Storm flow comprised 6% of total streamflow for the year studied, and 10% of streamflow during the rainy season. In the rainy season, over 90% of FPOC exports were transported by storm flow, while only 32% of DOC exports were exported by storm flow during this period. Streamwater DOC concentrations were found to increase linearly with increasing terrestrial litterfall during the dry season (r2 = 0·92, p < 0·001), indicating that in‐stream processing of allochthonous litterfall is an important source of DOC during the dry season. Copyright © 2006 John Wiley & Sons, Ltd.
A modified technique for the impregnation of lanthanum tracer to study the integrity of tight junctions on cells grown on a permeable substrate
Authors: Nilsson Harriet , Dragomir Anca , Ahlander Anders , Ljungkvist Marianne , Roomans Godfried M.
Published: July 2006

Ionic lanthanum is commonly used to trace permeability pathways across epithelia and endothelia in biological electron microscopy. A method for obtaining a uniformly dense precipitate of lanthanum is described. The method, which is a modification of the technique described by Shaklai and Tavassoli (1977) was suitable for fixation of cell cultures grown on permeable filter inserts and was successfully applied to study opening of tight junctions by hypertonic solutions in the airway epithelial cell line 16HBE14o−. The preparation method formed the basis for a semiquantitative morphological determination in which the tight junctions were subdivided as “intact,” “weakened,” and “open.” By using this modified technique, it could be demonstrated that opening of tight junctions in airway epithelial cells increased, with increasing osmolarity with electrolytes having a stronger effect than nonelectrolytes. A significant linear relationship was found between the osmolarity of the medium and the open state of the tight junctions (as determined by the semiquantitative morphological technique) or the transepithelial electrical resistance. Microsc. Res. Tech., 2006. © 2006 Wiley‐Liss, Inc.
Aid, restitution and international fiscal redistribution in health care: implications of health professionals' migration
Authors: Mackintosh Maureen , Mensah Kwadwo , Henry Leroi , Rowson Michael
Published: July 2006

High and sustained levels of migration of health professionals from labour‐short health services in low‐income countries to the health services of rich countries create a perverse subsidy from poor to rich, flowing across national boundaries. This subsidy worsens international inequality, and creates an obligation, both ethical and legal, for the payment of restitution. Drawing on the case of the migration of health professionals from Sub‐Saharan Africa to the UK, we argue that this obligation in turn constitutes an opportunity to shift development aid relationships away from a framework of charity towards a less neo‐colonial commitment to progressive international fiscal transfers. Copyright © 2006 John Wiley & Sons, Ltd.