bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of Diabetes and Impaired Fasting Glucose in Adults in the U.S. Population
Authors: Cowie Catherine C. , Rust Keith F. , Byrd-Holt Danita D. , Eberhardt Mark S. , Flegal Katherine M. , Engelgau Michael M. , Saydah Sharon H. , Williams Desmond E. , Geiss Linda S. , Gregg Edward W.
Published: May 2006

OBJECTIVE—The purpose of this study was to examine the prevalences of diagnosed and undiagnosed diabetes, and impaired fasting glucose (IFG) in U.S. adults during 1999–2002, and compare prevalences to those in 1988–1994.

RESEARCH DESIGN AND METHODS—The National Health and Nutrition Examination Survey (NHANES) contains a probability sample of adults aged ≥20 years. In the NHANES 1999–2002, 4,761 adults were classified on glycemic status using standard criteria, based on an interview for diagnosed diabetes and fasting plasma glucose measured in a subsample.

RESULTS—The crude prevalence of total diabetes in 1999–2002 was 9.3% (19.3 million, 2002 U.S. population), consisting of 6.5% diagnosed and 2.8% undiagnosed. An additional 26.0% had IFG, totaling 35.3% (73.3 million) with either diabetes or IFG. The prevalence of total diabetes rose with age, reaching 21.6% for those aged ≥65 years. The prevalence of diagnosed diabetes was twice as high in non-Hispanic blacks and Mexican Americans compared with non-Hispanic whites (both P < 0.00001), whereas the prevalence of undiagnosed diabetes was similar by race/ethnicity, adjusted for age and sex. The prevalence of diagnosed diabetes was similar by sex, but prevalences of undiagnosed diabetes and IFG were significantly higher in men. The crude prevalence of diagnosed diabetes rose significantly from 5.1% in 1988–1994 to 6.5% in 1999–2002, but the crude prevalences were stable for undiagnosed diabetes (from 2.7 to 2.8%) and IFG (from 24.7 to 26.0%). Results were similar after adjustment for age and sex.

CONCLUSIONS—Although the prevalence of diagnosed diabetes has increased significantly over the last decade, the prevalences of undiagnosed diabetes and IFG have remained relatively stable. Minority groups remain disproportionately affected.
Iron Intake and the Risk of Type 2 Diabetes in Women
Authors: Rajpathak Swapnil , Ma Jing , Manson JoAnn , Willett Walter C. , Hu Frank B.
Published: May 2006

OBJECTIVE—Epidemiological studies suggest that high body iron stores are associated with insulin resistance and type 2 diabetes. The aim of this study was to evaluate the association between dietary intake of iron and the risk of type 2 diabetes.

RESEARCH DESIGN AND METHODS—We conducted a prospective cohort study within the Nurses’ Health Study. We followed 85,031 healthy women aged 34–59 years from 1980 to 2000. Dietary data were collected every 4 years, and data on medical history and lifestyle factors were updated biennially.

RESULTS—During the 20 years of follow-up, we documented 4,599 incident cases of type 2 diabetes. We found no association between total, dietary, supplemental, or nonheme iron and the risk of type 2 diabetes. However, heme iron intake (derived from animal products) was positively associated with risk; relative risks (RRs) across increasing quintiles of cumulative intake were 1.00, 1.08 (95% CI 0.97–1.19), 1.20 (1.09–1.33), 1.27 (1.14–1.41), and 1.28 (1.14–1.45) (Ptrend < 0.0001) after controlling for age, BMI, and other nondietary and dietary risk factors. In addition, when we modeled heme iron in seven categories, the multivariate RR comparing women who consumed ≥2.25 mg/day and those with intake <0.75 mg/day was 1.52 (1.22–1.88). The association between heme iron and the risk of diabetes was significant in both overweight and lean women.

CONCLUSIONS—This large cohort study suggests that higher heme iron intake is associated with a significantly increased risk of type 2 diabetes.
Relations Between Carotid Artery Wall Thickness and Liver Histology in Subjects With Nonalcoholic Fatty Liver Disease
Authors: Targher Giovanni , Bertolini Lorenzo , Padovani Roberto , Rodella Stefano , Zoppini Giacomo , Zenari Luciano , Cigolini Massimo , Falezza Giancarlo , Arcaro Guido
Published: May 2006

OBJECTIVE—Nonalcoholic fatty liver disease (NAFLD) is closely associated with several metabolic syndrome features. We assessed whether NAFLD is associated with carotid artery intima-media thickness (IMT) as a marker of subclinical atherosclerosis and whether such an association is independent of classical risk factors, insulin resistance, and metabolic syndrome features.

RESEARCH DESIGN AND METHODS—We compared carotid IMT, as assessed by ultrasonography, in 85 consecutive patients with biopsy-proven NAFLD and 160 age-, sex-, and BMI-matched healthy control subjects.

RESULTS—NAFLD patients had a markedly greater carotid IMT (1.14 ± 0.20 vs. 0.82 ± 0.12 mm; P < 0.001) than control subjects. The metabolic syndrome (according to Adult Treatment Panel III criteria) and its individual components were more frequent in those with NAFLD (P < 0.001). The marked differences in carotid IMT observed between the groups were only slightly weakened after adjustment for age, sex, BMI, smoking history, LDL cholesterol, insulin resistance (by homeostasis model assessment), and metabolic syndrome components. Notably, carotid IMT was strongly associated with degree of hepatic steatosis, necroinflammation, and fibrosis among NAFLD patients (P < 0.001 for all). Similarly, by logistic regression analysis, the severity of histological features of NAFLD independently predicted carotid IMT (P < 0.001) after adjustment for all potential confounders.

CONCLUSIONS—These results suggest that the severity of liver histopathology among NAFLD patients is strongly associated with early carotid atherosclerosis, independent of classical risk factors, insulin resistance, and the presence of metabolic syndrome.
Lifestyle Intervention for Pre-Diabetic Neuropathy
Authors: Smith A. Gordon , Russell James , Feldman Eva L. , Goldstein Jonathan , Peltier Amanda , Smith Sheldon , Hamwi Jouhaina , Pollari Donald , Bixby Billie , Howard James , Singleton J. Robinson
Published: May 2006

OBJECTIVE—The purpose of this study was to evaluate intraepidermal nerve fiber density (IENFD) as a sensitive measure of neuropathy change in patients with neuropathy associated with impaired glucose tolerance (IGT) receiving lifestyle intervention based on that used in the Diabetes Prevention Program.

RESEARCH DESIGN AND METHODS—We performed 3-mm skin biopsies with measurement of IENFD at the distal leg and proximal thigh at baseline and after 1 year in 32 subjects with IGT. Each received individualized diet and exercise counseling as a standard of care. Nerve conduction studies, quantitative sensory testing, quantitative sudomotor axon reflex testing, and the Michigan Diabetic Neuropathy score were performed, and a visual analog pain scale was completed. Two-hour oral glucose tolerance tests (OGTTs) following the American Diabetes Association guidelines were performed, and serum lipid levels were measured at baseline and 1 year later.

RESULTS—Baseline distal IENFD was 0.9 ± 1.2 fibers/mm and proximal IENFD was 4.8 ± 2.3 fibers/mm. Baseline distal IENFD correlated with fasting glucose (P < 0.001) and OGTT (P < 0.01). After 1 year of treatment, there was a 0.3 ± 1.1-fiber/mm improvement in distal IENFD and a 1.4 ± 2.3-fiber/mm improvement in proximal IENFD (P < 0.004). The change in proximal IENFD correlated with decreased neuropathic pain (P < 0.05) and a change in sural sensory amplitude (P < 0.03).

CONCLUSIONS—These findings indicate that diet and exercise counseling for IGT results in cutaneous reinnervation and improved pain. Skin biopsy was the most sensitive measure of neuropathy change over 1 year. IENFD should be included as an end point in future neuropathy trials.
Assessment of Patients’ and Physicians’ Compliance to an ACE Inhibitor Treatment Based on Urinary N-Acetyl Ser-Asp-Lys-Pro Determination in the Noninsulin-Dependent Diabetes, Hypertension, Microalbuminuria, Proteinuria, Cardiovascular Events, and Ramipril (DIABHYCAR) Study
Authors: Azizi Michel , Ménard Joël , Peyrard Séverine , Lièvre Michel , Marre Michel , Chatellier Gilles
Published: May 2006

OBJECTIVE—The purpose of this study was to assess patients’ and physicians’ compliance with ACE inhibitor treatment, by measuring an endogenous biomarker of ACE inhibition, urinary N-acetyl-Ser-Asp-Lys-Pro (AcSDKP), in the Noninsulin-Dependent Diabetes, Hypertension, Microalbuminuria, Proteinuria, Cardiovascular Events, and Ramipril (DIABHYCAR) trial, which compared ramipril (1.25 mg o.d.) with placebo in 4,912 patients with type 2 diabetes and microalbuminuria/proteinuria.

RESEARCH DESIGN AND METHODS—The urine AcSDKP-to-creatinine ratio was measured blind to treatment in all participants who completed follow-up and provided spot urine samples (n = 1,871).

RESULTS—The median urinary AcSDKP-to-creatinine ratio was six times higher for ramipril than for placebo. Urinary AcSDKP-to-creatinine ratios displayed a bimodal distribution in both groups, with a very large intergroup overlap. Based on cluster analysis, we defined truly adherent ramipril patients as those with a ratio ≥4 nmol/mmol and truly adherent placebo patients as those with a ratio <4 nmol/mmol. After excluding patients withdrawing prematurely from the study or known to have used a nonstudy ACE inhibitor, 27.3% of the 597 ramipril patients had ratios <4, indicating poor compliance, and 9.7% of the 621 placebo patients had ratios ≥4, indicating intake of a nonstudy ACE inhibitor. Correcting for compliance by using AcSDKP-guided analysis affected surrogate outcome results (decrease in systolic blood pressure and urinary albumin excretion) only slightly.

CONCLUSIONS—The systematic use of spot urinary AcSDKP determination facilitated the detection of defects in compliance with ACE inhibitor treatment in both patients and physicians. Urinary AcSDKP measurement could be a useful biomarker for assessing compliance with ACE inhibition in the routine care of diabetic patients.
1,5-Anhydroglucitol and Postprandial Hyperglycemia as Measured by Continuous Glucose Monitoring System in Moderately Controlled Patients With Diabetes
Authors: Dungan Kathleen M. , Buse John B. , Largay Joseph , Kelly Mary M. , Button Eric A. , Kato Shuhei , Wittlin Steven
Published: May 2006

OBJECTIVE—Postprandial hyperglycemia is often inadequately assessed in diabetes management. Serum 1,5-anhydroglucitol (1,5-AG) drops as serum glucose rises above the renal threshold for glucose and has been proposed as a marker for postprandial hyperglycemia. The objective of this study is to demonstrate the relationship between 1,5-AG and postprandial hyperglycemia, as assessed by the continuous glucose monitoring system (CGMS) in suboptimally controlled patients with diabetes.

RESEARCH DESIGN AND METHODS—Patients with type 1 or type 2 diabetes and an HbA1c (A1C) between 6.5 and 8% with stable glycemic control were recruited from two sites. A CGMS monitor was worn for two consecutive 72-h periods. Mean glucose, mean postmeal maximum glucose (MPMG), and area under the curve for glucose above 180 mg/dl (AUC-180), were compared with 1,5-AG, fructosamine (FA), and A1C at baseline, day 4, and day 7.

RESULTS—1,5-AG varied considerably between patients (6.5 ± 3.2 μg/ml [means ± SD]) despite similar A1C (7.3 ± 0.5%). Mean 1,5-AG (r = −0.45, P = 0.006) correlated with AUC-180 more robustly than A1C (r = 0.33, P = 0.057) or FA (r = 0.38, P = 0.88). MPMG correlated more strongly with 1,5-AG (r = −0.54, P = 0.004) than with A1C (r = 0.40, P = 0.03) or FA (r = 0.32, P = 0.07).

CONCLUSIONS—1,5-AG reflects glycemic excursions, often in the postprandial state, more robustly than A1C or FA. 1,5-AG may be useful as a complementary marker to A1C to assess glycemic control in moderately controlled patients with diabetes.
Inside Front Cover: Rigid, Self‐Assembled Hydrogel Composed of a Modified Aromatic Dipeptide (Adv. Mater. 11/2006)
Authors: Mahler A. , Reches M. , Rechter M. , Cohen S. , Gazit E.
Published: May 2006

Formation of a self‐assembled hydrogel with remarkable mechanical rigidity using a very simple building block, 9‐fluorenylmethoxycarbonyl‐diphenylalanine peptide, is reported by Gazit and co‐workers on p. 1365. The hydrogel forms under mild conditions in aqueous solution, using a much shorter peptide than previously reported, and has physical properties exceeding those of hydrogels formed by much longer polypeptides, as previously reported for diphenylalanine nanotubes. The rigidity is likely facilitated by the aromatic nature of the peptide building block. The hydrogel is stable under extreme conditions, and can be shaped in accordance to the vessel it is assembled in, making it useful for a variety of applications.
„Fremde Körperwelten”︁. Russische Anthropologie und Medizin im kolonialen Diskurs des ausgehenden Zarenreiches
Authors: Stolberg Eva‐Maria
Published: May 2006

„Exotic Bodies”︁: Russian Anthropology and Medicine in the Colonial Discours of Late Imperial Russia. In the nineteenth century Russian anthropologists adopted Western theories on the biological superiority of the white man in order to justify Russian colonization at the Asiatic periphery. After the Great Reforms the imperial process of acculturation was discussed in the context of modernization that also touched the institutionalization of colonial medicine. Whereas Russian armchair anthropologists were operating with racial idioms, physicians as practitioners on the colonial spot were not receptive to the ideology of “white man's burden”. From experience with the socioeconomic backwardness of Russia's Asiatic periphery physicians stood up for the vital rights of the indigenous population in the colonial Public Health. With deep respect for indigenous medicine Russian physicians were not advocates of Russian colonial expansion and racial discrimination that made them different to their Western colleagues. On the basis of Russian nineteenth century medical literature and Siberian archival sources this paper outlines the critical reflections of Russian physicians on Tsarist colonialism
Wissenschaftswachstum in wichtigen naturwissenschaftlichen Disziplinen vom 17. bis zum 21. Jahrhundert
Authors: Behrens Heinrich , Lankenau Irmgard
Published: May 2006

The Growth of Science within Important Scientific Disciplines from 17th to 21st century. – In this paper the growth of knowledge is investigated for the disciplines of Astrophysics / Astronomy, of Physics and of Chemistry in the last centuries. In this context the main emphasis is devoted to the discussion of the growth of literature. Besides, this is also illustrated by the growth of indicators like for example important books, new discoveries in science, the chemical elements, the known chemical compounds and the number of known inorganic chemical structures. Compared to numerous earlier studies a systematic evaluation of all presently available data sources is carried out. The data are fitted by different mathematical growth models (linear, quadratic, exponential, hyperbolic). These are discussed and compared. As far as the exponential growth model is applied the doubling periods obtained have values between 11 and 32 years for the cumulative total of publications, between 24 and 98 years for that of important books, between 79 and 163 years for that of new discoveries and between 10 and 14 years for that of chemical substances. From an order of magnitude point of view this is in agreement with the results of other authors. It is however also demonstrated that the exponential growth model which is normally used is not necessarily the best to describe the growth of the data. Other models are often better suitable to explain the growth. It is shown that linear growth of the yearly publications describes the data better than exponential growth in certain epochs. In this latter case it is demonstrated that the parameter (linear slope) for the rate of increase has a constant values in certain epochs, but rises in steps from epoch to epoch by a factor of 3 to 40. After the second world war the linear growth model for the yearly publications or the quadratic growth model for the cumulative total of publications respectively delivers the best results. This is therefore used for forecasting the future.
Maximally Selected Chi‐Square Statistics and Binary Splits of Nominal Variables
Authors: Boulesteix Anne‐Laure
Published: May 2006

We address the problem of maximally selected chi‐square statistics in the case of a binary Y variable and a nominal X variable with several categories. The distribution of the maximally selected chi‐square statistic has already been derived when the best cutpoint is chosen from a continuous or an ordinal X, but not when the best split is chosen from a nominal X. In this paper, we derive the exact distribution of the maximally selected chi‐square statistic in this case using a combinatorial approach. Applications of the derived distribution to variable selection and hypothesis testing are discussed based on simulations. As an illustration, our method is applied to a birth data set. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, Electrochemical and Electrogenerated Chemiluminescence Studies of Ruthenium(II) Bis(2,2′‐bipyridyl){2‐(4‐methylpyridin‐2‐yl)benzo[d]‐X‐azole} Complexes
Authors: Gobetto Roberto , Caputo Giuseppe , Garino Claudio , Ghiani Simona , Nervi Carlo , Salassa Luca , Rosenberg Edward , Ross J. B. Alexander , Viscardi Guido , Martra Gianmario , Miletto Ivana , Milanesio Marco
Published: May 2006

A series of photoactive complexes of [RuIIbis(bipyridyl){2‐(4‐methylpyridin‐2‐yl)benzo[d]‐X‐azole}](PF6)2 (X = N–CH3, 1; S, 2; or O, 3) have been synthesized and fully characterized by proton and 13C NMR spectroscopy and UV/Vis spectroscopy. The X‐ray structure of 1 is also reported. The electrochemical behavior and the photophysical properties of 1–3 have been investigated. Cyclic voltammetry (CV) reveals the presence of three consecutive one‐electron reduction processes and a single one‐electron oxidation process that are chemically and electrochemically reversible. In all cases, electrogenerated chemiluminescence (ECL) has been observed in the presence of the co‐reactant tri‐n‐propylamine (TPA). An analogue of 1 has been synthesized, [RuIIbis(bipyridyl){2‐(4‐methylpyridin‐2‐yl)benzo[d]‐X‐azole}](PF6)2 [X = N(CH2)5CO2H, 4], it has been coupled with bovine serum albumin (BSA), and its photophysical properties investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Tricarbonylchlororhenium(I) Carboxaldimine Derivatives: Synthesis, Structure, and NMR Characterization of Z and E Isomers
Authors: Garino Claudio , Ghiani Simona , Gobetto Roberto , Nervi Carlo , Salassa Luca , Croce Gianluca , Milanesio Marco , Rosenberg Edward , Ross J. B. Alexander
Published: May 2006

The ligand N‐(2‐pyridylmethyl)anthracene‐9‐carboxaldimine (1) has been synthesized and characterized by NMR spectroscopic techniques. The experimental procedure leads selectively to the E isomer, which has been studied by a combined theoretical (Density Functional Theory) and 2D NOESY NMR spectroscopic approach. The trifluoroacetic acid promotes the E to Z isomerization of 1. The process has been investigated by NMR spectroscopy and computationally for the neutral ligand 1. DFT methods calculate that the E isomer is 2.2 kcal/mol more stable than the Z isomer, whereas the reverse situation is observed for the protonated species, where the Z isomer is 4.5 kcal/mol more stable than the E isomer. Transition state calculations for the interconversion of the neutral and protonated E species into their corresponding Z isomers show that the energy barriers are 27.6 and 20.3 kcal/mol for the neutral and protonated species, respectively. The reaction with pentacarbonylchlororhenium leads, in the absence and in the presence of trifluoroacetic acid, to the synthesis of the corresponding tricarbonylchlororhenium isomer complexes Re‐E‐1 and Re‐Z‐1, respectively. Compounds Re‐E‐1 and Re‐Z‐1 were characterized by 1D and 2D NMR spectroscopy in solution, and their crystal structures were determined. Their photophysical and electrochemical properties are also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Preparation, Characterization, and Aquation Kinetics of Pyridine N‐Oxide Complexes of Chromium(III)
Authors: Kotowski Mirjana , Marcec Radovan , Butkovic Vjera , Bakac Andreja , Orhanovic Matko
Published: May 2006

A series of (H2O)5Cr(X‐pyO)3+ ions (pyO = pyridine N‐oxide, X = H, 3‐CH3, 4‐CH3, 4‐OCH3, 4‐NO2) were prepared by the reduction of the corresponding pyridine N‐oxide adducts of diperoxochromium(VI) species with acidic ferrous perchlorate. The (H2O)5Cr(X‐pyO)3+ complexes undergo aquation to yield Cr(H2O)63+ and X‐pyO according to the rate law kobs = ko + k–1[H+]–1. The values of the rate constants extrapolated to 298 K at 1.0 M ionic strength are: k0 = 2.80 × 10–6 s–1, k–1 = 1.86 × 10–8 M s–1 (X = 4‐NO2); 7.80 × 10–8, 6.27 × 10–10 (H);4.80 × 10–8, 3.20 × 10–10 (3‐CH3); 3.05 × 10–8, 1.60 × 10–10 (4‐CH3); and 2.37 × 10–9, 4.76 × 10–11 (4‐OCH3). The reaction of the 4‐OCH3 complex exhibits two additional terms in the rate law, k1[H+] + k–2[H+]–2. The binding of 4‐OCH3–pyO to chromium is suggested to take place through the methoxy group. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Convenient Synthetic Route to Tetrahydropyran‐Based Liquid Crystals
Authors: Kirsch Peer , Maillard David
Published: May 2006

The tetrahydropyran moiety has been identified as a highly advantageous addition to the toolbox for the design of nematic liquid crystals for LCD applications. A new synthetic procedure based on the Lewis acid catalysed ring opening of oxetanes by lithium iminoenolates followed by reductive dehydroxylation of the resulting hemiketal provides a convenient preparative access to this class of materials.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Characterization of the antioxidative activity of novel nontoxic neuropeptides by using capillary electrophoresis
Authors: Vaher Merike , Viirlaid Säde , Ehrlich Kersti , Mahlapuu Riina , Jarvet Jüri , Soomets Ursel , Kaljurand Mihkel
Published: May 2006

In the present study, we have monitored the oxidation process of novel nontoxic neuropeptides and determined its rate constants, which describe the antioxidative potential of the peptides. A capillary electrophoretic method was implemented which ensures the simultaneity of analysis of reactants and products in a short time of analysis. The rate constants of oxidation of the four novel peptides, 4‐methoxy‐L‐tyrosinyl‐γ‐L‐glutamyl‐L‐cysteinyl‐glycine (UPF1), D‐serinyl‐γ‐L‐glutamyl‐L‐cysteinyl‐glycine (UPF6), 4‐methoxy‐L‐tyrosinyl‐α‐L‐glutamyl‐L‐cysteinyl‐glycine and D‐serinyl‐α‐L‐glutamyl‐L‐cysteinyl‐glycine, designed by us, were compared with those of oxidation of glutathione (reduced glutathione) by using capillary electrophoresis. The second‐order rate constants were similar for all peptides if the oxidation was carried out with hydrogen peroxide (kII = 0.208 — 0.236×103/M·min). The rate constants were also determined for the mixtures of peptides. When the oxidation is caused by hydroxyl radical (OH*), the γ‐glutamate containing peptides (UPF1 and UPF6) exhibited two to four times higher antioxidative activity (kII =  4.428 and 2.152×103/M·min, respectively). The results suggest that the antioxidative potential of the peptides studied is not determined by the formation of disulphide bridge alone.
Bioanalytical interaction studies executed by preincubation affinity capillary electrophoresis
Authors: Østergaard Jesper , Heegaard Niels H. H.
Published: May 2006

The versatility of CE is beneficial for the study of many types of molecular interactions, because different experimental designs can be made to suit the characteristics of a particular interaction. A very versatile starting point is the preequilibration type of affinity CE that has been used extensively for characterizing biomolecular interactions in the last 15 years. We review this field here and include a comprehensive overview of the existing preincubation ACE modes including their advantages and limitations as well as the methodological developments and applications within the bioanalytical field.
Cover Picture: Macromol. Rapid Commun. 11/2006
Authors: Millard Pierre‐Eric , Barner Leonie , Stenzel Martina H. , Davis Thomas P. , Barner‐Kowollik Christopher , Müller Axel H. E.
Published: May 2006

Cover: γ‐Initiated living free radical polymerization (RAFT) at ambient temperature of N‐isopropyl acrylamide and acrylic acid in aqueous media provides facile access to extremely low polydispersity high molecular weight stimuli responsive polymers. Further details can be found in the article by P.‐E. Millard, L. Barner, M. H. Stenzel, T. P. Davis, C. Barner‐ Kowollik,* and A. H. E. Müller* on page 821.
A Discrete, Space Variation Model for Studying the Kinetics of Shape Deformation of Vesicles Coupled with Phase Separation
Authors: Li Jianfeng , Zhang Hongdong , Tang Ping , Qiu Feng , Yang Yuliang
Published: May 2006

Summary: The evolution dynamics of phase separation, coupled with shape deformation of vesicles is described by using dissipative dynamic equations, specifically the time‐dependent Ginzburg‐Landau (TDGL) equations. In order to improve the numerical stability and thus to efficiently deal with a large deformation of vesicles, a new algorithm, namely the discrete space variation model (DSVM) has been developed for the first time. The algorithm is based on the variation of the discretized free‐energy functional, which is constructed in discrete membrane space, in contrast to the commonly used continuous free‐energy functional. For the sake of numerical tractability, only the cylindrical vesicles (2D), with two components, are taken into consideration to illustrate the efficiency and validity of new algorithm. The simulation results, based on the DSVM algorithm have been compared with those from both linear analysis and strong segregation theory using the continuous space free‐energy functional. It is found that the DSVM algorithm can correctly describe the coupling between the lateral phase‐separation on the vesicle membrane and the vesicle shape deformation, both for early and late stages.

A flower‐like vesicle obtained by DSVM simulation.

magnified image

A flower‐like vesicle obtained by DSVM simulation.
Surface enhanced Raman scattering by GaN nanocolumns
Authors: Milekhin A. G. , Meijers R. , Richter T. , Calarco R. , Lüth H. , Paez Sierra B. A. , Zahn D. R. T.
Published: May 2006

The GaN nanocolumns were grown by plasma‐assisted molecular beam epitaxy (PAMBE) on Si(111) substrates. Scanning electron microscopy shows that the nanocolumns with diameters of 20–150 nm and lengths of 300‐500 nm grow parallel to the [111] direction of the Si substrate. The vibrational spectrum (including optical and interface phonons) of the nanocolumns was studied using conventional and surface enhanced Raman scattering. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaluation of strain in AlN thin films grown on sapphire and 6H‐SiC by metalorganic chemical vapor deposition
Authors: Kato Naoto , Inushima Takashi
Published: May 2006

The effect of growth rate on the strain in AlN films grown on sapphire and 6H‐SiC c‐planes at 1150 °C by metalorganic chemical vapor deposition was investigated. The strain was measured by X‐ray diffraction and Raman spectroscopy. It was found that the strain in the films was expressed by the biaxial stress and that it depended on the growth rate of the films and on the surface pre‐treatments. When the growth rate was lower than 2.4 nm/min, the strain was constant, and it was compressive for the films grown on sapphire, and tensile for those on 6H‐SiC. These stresses were produced by the differences of the thermal expansion coefficients between the films and substrates. The low temperature AlN‐buffer layer, which was useful for the high temperature growth of AlN on sapphire, was revealed not to be applicable for 6H‐SiC. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Observation of a filled electronic state in the conduction band of InN
Authors: Kim J. J. , Makino H. , Kobayashi K. , Chen P. P. , Ikenaga E. , Kobata M. , Takeuchi A. , Awaji M. , Hanada T. , Cho M. W. , Yao T.
Published: May 2006

We have investigated the electronic structure of InN epilayers grown by molecular beam epitaxy at different growth temperatures by hard X‐ray photoemission spectroscopy. We observed filled electronic states in the conduction band of the InN films. Integral intensity of the filled electronic states developed with decreasing growth temperature. The decreasing growth temperature induced increasing oxygen incorporation into the InN films and increasing carrier concentration and optical band gap of the InN films. Therefore, the filled electronic states should be indicated the filling of carriers in the conduction band caused by oxygen incorporation and the present results support the Burstein‐Moss shift. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical properties of Ni/i‐AlGaN/GaN structures and influence of thermal annealing
Authors: Sawada T. , Kimura N. , Suzuki K. , Imai K. , Kim S.‐W. , Suzuki T.
Published: May 2006

Electrical properties of Ni/i‐AlGaN/GaN heterostructures prepared by various surface preparation conditions have been studied by I‐V and C‐V measurements. The surface native oxide lowered the effective Schottky barrier height (SBH) accompanied with significant increase of the reverse leakage current. Tunneling together with surface patches seems to take part in the reverse leakage current. Annealing in N2 improved the effective SBH and the leakage current. The optimum annealing temperature depended on both the surface preparation condition and the Al composition. Insertion of a thin anodic Al2O3 layer between Ni and i‐AlGaN effectively reduced the leakage current to 10–6 A/cm2. Hall effect measurements revealed that tharmal annealing of bare i‐AlGaN(x = 0.20)/GaN heterostructures, at above 600 °C, leads to reduction of the electron mobility and the 2DEG density. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anisotropic ambipolar diffusion of carriers in InGaN/GaN quantum wells
Authors: Wang Y. J. , Xu S. J. , Li Q.
Published: May 2006

By directly imaging the photoluminescence of the samples, we observe strong anisotropic lateral diffusion of photogenerated carriers in InGaN/GaN quantum‐wells structures. For quantitative interpretation of the phenomenon, the ambipolar diffusion of carriers in such structures is calculated using the two‐dimensional drift‐diffusion equation when the huge piezoelectric field in the strained InGaN/GaN quantum wells is taken into account. Very good agreement between theory and experiment is achieved. Our results show that the strong piezoelectric field and crystalline direction dependence of the carrier mobility are responsible for the enhancement and anisotropy of carriers' lateral diffusion, respectively. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Depth profiling of ion‐implanted AlInN using time‐of‐flight secondary ion mass spectrometry and cathodoluminescence
Authors: Martin R. W. , Rading D. , Kersting R. , Tallarek E. , Nogales E. , Amabile D. , Wang K. , Katchkanov V. , Trager‐Cowan C. , O'Donnell K. P. , Watson I. M. , Matias V. , Vantomme A. , Lorenz K. , Alves E.
Published: May 2006

Investigation of the depth profiles and luminescence of Eu and Er‐ions implanted into AlInN/GaN bilayers differentiates between ions located in the two different III‐N hosts. Differences between samples implanted using channeling or off‐axis geometries are studied using time‐of‐flight secondary ion mass spectometry. A fraction of ions have crossed the AlInN layer (either 130 or 250 nm thick) and reached the underlying GaN. Cathodoluminescence spectra as a function of incident electron energy and photoluminescence excitation data distinguish between ions within AlInN and GaN. The RE emission from the AlInN is broader and red‐shifted and the dependence of the intensity on host is discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Diffusion lengths in GaN obtained from steady state photocarrier gratings (SSPG)
Authors: Niehus M. , Schwarz R.
Published: May 2006

We present diffusion length measurements in gallium nitride (GaN) and AlXGa1–XN/GaN multilayers with aluminium contents up to Xmax = 37 at.%. The opto‐electrical method employed is the steady‐state photocarrier grating (SSPG), which uses two interfering laser beams to induce a periodic resistivity modulation normal to the sense current lines. We experimentally refined the SSPG, using a double beamsplitter technique and introducing a variable ND filter. We measured diffusion lengths of single GaN and AlXGa1–XN/GaN double layers, and analysed the obtained diffusion lengths as function of the aluminium concentration, comparing them with the respective drift lengths. Finally, we critically discuss the common interpretation in terms of ambipolar transport. We suggest a new model in which minority carriers are rapidly trapped in acceptor‐like valence band tails and participate in the grating blurring passively, as spatially localized recombination centres. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recent results on AlN growth by HVPE and fabrication of free standing AlN wafers
Authors: Soukhoveev V. , Kovalenkov O. , Ivantsov V. , Syrkin A. , Usikov A. , Maslennikov V. , Dmitriev V.
Published: May 2006

Properties of thick crack‐free AlN layers grown by hydride vapor phase epitaxy (HVPE) on 2‐inch and 3‐inch silicon carbide (SiC) and sapphire substrates are described. The maximum thickness of crack free layer was 75 μm and 15 μm for AlN grown on SiC and sapphire, respectively. Wafer bow was contolled below 50 μm for AlN/SiC wafers. Surface for as‐grown and polished AlN surface was studied. X‐ray diffraction and wet chemical etching was used for crystal quality evaluation showing defect density in high 107 to low 108 cm–2 range. Initial experiments on AlN growth on patterened SiC wafers resulted in local etch pit density of about 2x107 cm–2 for 35 μm thick AlN layer. Electrical resistivity of AlN layers exceeded 1011 and 106 Ω cm at 300 K and 600 K, respectively. Free‐standing 2‐inch AlN wafers were fabricated by removal of SiC substrate using reactive ion etching. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
[Sb11]3− and [As11]3−: Synthesis and Crystal Structure of Two New Ammoniates containing Trishomocubane‐like Polyanions
Authors: Hanauer Tobias , Korber Nikolaus
Published: May 2006

The ammoniates [K(18‐crown‐6)(NH3)2]3Sb11 · 5.5NH3 (1) and [Cs(18‐crown‐6)]2CsAs11 · 8NH3 (2) (18‐crown‐6 = 18C6: 1,4,7,10,13,16‐Hexaoxacyclooctadecan) were synthesized by either the reaction of K3Sb7 with SbPh3 in liquid ammonia or by extraction of Cs3As11 with liquid ammonia. Single crystals were isolated and characterized by low temperature X‐ray structure analysis. [K(18‐crown‐6)(NH3)2]3Sb11 · 5.5NH3 crystallizes in the space group $P{\bar 1}$ with a = 13.31(2) Å, b = 15.161(2) Å, c = 22.521(3) Å, α = 99.23(1)°, β = 100.99(1)° and γ = 105.03(1)°. [Cs(18‐crown‐6)]2CsAs11 · 8NH3 crystallizes in the monoclinic space group C2/c with a = 20.009(3) Å, b = 17.024(1) Å, c = 19.838(2) Å and β = 119.732(9)°. While 1 contains isolated [Sb11]3− anions and [K(18‐crown‐6)(NH3)2]+ complexes, cesium–arsenic contacts lead to one–dimensionally infinite $^{1}_{\infty}\rm [CsAs_{11}]^{2-}$ chains in 2.
Structure Motifs of Sodium Stannides on the Tin‐rich Side of the Phase Diagram
Authors: Fässler Thomas F.
Published: May 2006

The flexibility of the Sn‐Sn bond is acknowledged by the structural variety of compounds which are formed between tin and electropositive metals as minority components. As demonstrated for Na/Sn, already in the case of simple, binary systems a plethora of different structural motifs becomes obvious. Although the phase diagram of sodium and tin has been studied extensively for many years, the series of sodium stannides could be complemented by several new representatives during the last few years.
Structure and Stability of TaON Polymorphs
Authors: Bredow Thomas , Lumey Marck‐Willem , Dronskowski Richard , Schilling Heikko , Pickardt Joachim , Lerch Martin
Published: May 2006

The stabilities and electronic structures of several polymorphs of tantalum oxynitride, TaON, were studied quantum‐chemically at density‐functional level. Results obtained by complementary quantum‐chemical techniques with wave‐functions either expanded in atom‐centered functions or in plane waves were compared. Close agreement was obtained for the relative stabilities of the baddeleyite, anatase, rutile, and fluorite phases of TaON. The effect of anion distribution on the structural parameters and the lattice energies of the anatase and rutile polymorphs was investigated. The calculated band structure of the polymorphs is compared with available experimental information.
Synthesis and Characterization of Na5[VO4][O] and Na4[VO4][OH]
Authors: Kerp Oliver , Möller Angela
Published: May 2006

Na5[VO4][O] and Na4[VO4][OH] were obtained from reactions of V2O5 with Na2O and additional NaOH in the latter case, respectively, at 600‐700 °C in sealed Ag containers under Ar atmosphere. The crystal structures have been determined from X‐ray single crystal data. The structures contain isolated [VO4]3− complexes and non‐coordinating oxide and hydroxide anions, respectively. Raman and infrared data is compared for both compounds and hydrogen bonding is discussed for Na4[VO4][OH].
Verbindungen A3M5 (A = Erdalkalimetall, M = Triel/Tetrel): Eine Fallstudie zur strukturellen und elektronischen Stabilität polarer intermetallischer Phasen
Authors: Rhode Michael , Wendorff Marco , Röhr Caroline
Published: May 2006

Compounds A3M5 (A = alkaline earth, M = triel/tetrel): A Case Study on Structural and Electronic Factors Stabilizing Polar Intermetallics

Starting from the non electron precise binary compounds Ca3Ga5/Sr3In5 (Hf3Ni2Si3 type) and Ba3Al5 at one hand and Ba3Pb5 (Pu3Pd5 type) at the other hand, a series of new ternary intermetallics of the general formula A3M5 (A: alkaline earth, M: triel/tetrel) has been synthesized, structurally characterized and studied by band structure calculations. The chemical substitution of M in A3M5 allows, via the continous variation of the radius ratio (rA:rM) and the valence electron number (VE/M) the detection of the geometrically and electronically determined stability ranges of the three structure types formed by the binary compounds. At values of rA:rM between 1.30 and 1.52 in the triel rich region of A3M′xM″5−x the Hf3Ni2Si3 type (orthorhombic, space group Cmcm) is formed: In Ca3Ga5 up to 1.8 Ga can be substituted by Al, in Sr3In5 similar amount of In can be replaced by either Al or Ga. The mixed trielide Sr3Al2.6Ga2.4 (a = 468.4(1), b = 1132.5(1), c = 1570.0(2) pm, R1 = 0.0261) can be obtained, although both corresponding binary phases are not known. At larger values of the ratio rA/rM as in Ba3Al3Ga2 (Ba3Al5 type, hexagonal, space group P63/mmc, a = 598.9(1), c = 1456.0(3) pm, R1 = 0.0353) layers of condensed M5 building blocks with Al‐Al partial bonds are formed. Substituting one In position in Sr3In5 against Pb results in the isotypic, but electron precise Zintl compound Sr3In4Pb (a = 506.1(1), b = 1191.8(3), c = 1650.2(4) pm, R1 = 0.0286), where the Fermi level in shifted into a distinct minimum of the density of states. Conversely, at the tetrele rich end of the series A3InxPb5−x, characterized by compounds of the Pu3Pd5 type (orthorhombic, space group Cmcm) with almost isolated nido clusters M5, a minimum of the DOS can be reached, if Pb is partially substituted by In (A3InxPb5−x with A = Sr/Ba: x = 0.7/0.6; a = 1084.6(2)/1118.6(2), b = 867.1(2)/904.4(1), c = 1104.8(2)/1133.9(2) pm, R1 = 0.0394/0.0434).
Characterization of Mixed Crystals in the System Cu2MnxCo1−xGeS4 and Investigations of the Tetrahedra Volumes
Authors: Bernert Thomas , Pfitzner Arno
Published: May 2006

In a series of investigations on normal tetrahedral compounds we present mixed crystals in the system Cu2MnxCo1−xGeS4 (0 < x < 1) and an inspection of their tetrahedra volumes. Cu2CoGeS4 crystallizes tetragonal in a stannite type structure, Cu2MnGeS4 crystallizes orthorhombic in the wurtzstannite structure type. The crystal structures of Cu2CoGeS4 and Cu2Mn0.68Co0.32GeS4 were refined from single crystal diffraction data. The refinement of Cu2CoGeS4 converged to R = 0.0547 and wR2 = 0.0847 for 299 unique reflections. The refinement of Cu2Mn0.68Co0.32GeS4 converged to R = 0.0481 and wR2 = 0.0877 for 1556 unique reflections. From these data the tetrahedra volumes of the end members and of Cu2Mn0.68Co0.32GeS4 are calculated. In Cu2CoGeS4 tetrahedra [MS4] are similar in size. In contrast, the differences of the volumes of the polyhedra [MS4] in the orthorhombic wurtzite superstructure type compounds Cu2MnGeS4 and Cu2Mn0.68Co0.32GeS4 are significant (M = Cu, Mn, (Mn0.68Co0.32), Co, Ge). From x = 0 to x = 0.5 the tetragonal structure type dominates while from x = 0.7 to the Cu2MnGeS4 end member the products crystallize in the orthorhombic structure type. Melting points of the mixed crystals decrease linearly with increasing manganese content.
PdAs2O6, das erste paramagnetische Palladiumoxid
Authors: Orosel Denis , Jansen Martin
Published: May 2006

PdAs2O6, the First Paramagnetic Palladium Oxide

Ssolid state reaction of palladium(II) oxide (PdO) and arsenic(V) oxide (As2O5) yielded an auburn colored microcrystalline powder of palladium(II) metaarsenate(V), PdAs2O6. The crystal structure of the compound belongs to the PbSb2O6 structure type, $P{\bar 3}{\rm 1}m$ (no. 162), a = 4.8196(0) Å, c = 4.6646(1) Å, V = 93.84(0) Å3 and Z = 1. The structure consists of layers of edge sharing AsO6 octahedra and PdO6 octahedra connecting them. This is one of the rare structures with divalent palladium in octahedral coordination by oxygen. The compound is paramagnetic and shows antiferromagnetic ordering at about 150 K, which is 5 times higher than that of the isotypic NiAs2O6 compound.
The Structural Systematics of Protonation of Some Important Nitrogen‐base Ligands. IV. Some Ethane‐1,2‐diaminium Univalent Anion Salt/1,10‐Phenanthroline (Hydrate) Arrays
Authors: Buttery Jarrod H. , Effendy  , Junk Peter C. , Mutrofin Siti , Skelton Brian W. , Whitaker Claire R. , White Allan H.
Published: May 2006

Syntheses and single crystal X‐ray structure characterisations are recorded for some novel series of crystalline complexes formed between salts of univalent anions of the ethane‐1,2‐diaminium cation, [enH2]X2, and 1,10‐phenanthroline (‘phen’), variously hydrated, thus: [enH2]X2·mphen(·nH2O), for m = 2, 4 and 10 (one example), n various. In all cases, the motifs constituting the arrays comprise columns of [enH2]2+ cations, carrying the protonic array but linked in a second dimension by hydrogen‐bonding to associated anions and water molecules (where present), expanding the column in some cases to form a sheet, different degrees of hydration compensating for changing anion bulk. In a third dimension the protonic hydrogen complement also links to the nitrogenous component of phen stacks which surround the column. Thus, for the m = 2 array, in a triclinic $P{\bar 1}$ cell, a, b, c broadly 10‐11 (x2), 7Å, α, β, γ 80, 70° (x2), the cation and phen columns lie parallel to c; in the unsolvated trichloroacetate compound, the cation column is associated with anions to either side, these linking into a sheet with water molecules in the more highly hydrated trifluoroacetate (‘tfa’) and nitrate (n = 2), and chloride and bromide (n = 4) arrays (the tfa adduct a superlattice doubled in c). In the m = 4 arrays, an additional phen stack is inserted, forming a sheet with the first in the second dimension for the perchlorate tetrahydrate array, the iodide pentahydrate counterpart being a 2 x c superlattice. A second nitrate salt, m = 10, n = 4, is also described, a complex array of multiple networks of the above type. Single crystal X‐ray structure determinations are also recorded for salts [phenH](PF6)·phen and [2,9‐Me2phenH](PF6). In the phen adduct, the protonic hydrogen atom is closely associated (N···H 0.90(4) Å) with one of the two independent phen moieties, these disposed alternately in a stack up b close to the 21 screw axis, so that the hydrogen bridges to the unprotonated moiety (H···N′ 2.36(4) Å) pitched at an angle of 47° to it in the screw‐related stack. In the Me2phen salt, the phen moieties lie in crystallographic mirror planes, normal to and stacked up b, with the protonic hydrogen atom contacting a PF6 fluorine atom (H···F 1.96(3) Å). The structure of unsolvated Me2phen is also recorded.
Solvothermal Synthesis and Crystal Structure of Mn2(C5H14N2)Sb2S5: A New Member of the Mn2(L)Sb2S5 Family (L is an Organic Structure Director)
Authors: Puls A. , Näther C. , Bensch W.
Published: May 2006

The new compound Mn2(C5H14N2)Sb2S5 (C5H14N2 = 1,3‐diaminopentane, DAPE) was prepared under solvothermal conditions using the elements as starting materials. The compound crystallizes in the orthorhombic space group Pbca with the lattice parameters a = 12.620(3), b = 11.877(2) and c = 21.814(4) Å. The primary building units are trigonal SbS3 pyramids and distorted MnS6 and MnS4N2 octahedra. These primary building blocks are joined to form Mn2Sb2S4 hetero‐cubane units which are then connected via common corners, edges and faces thus forming a second type of hetero‐cubane. The hetero‐cubanes are condensed into layers within the (001) plane. The connection mode yields ellipsoidal pores within the layers with dimensions of about 9·7.5Å. The N atoms of the structure directing amines are exclusively bound to one of the two crystallographically independent Mn2+ cations and they point into the pores and between the layers separating the layers from each other. The interlayer separation measures about 6.7Å. Whereas the MnS6 octahedron shows only a moderate distortion the MnS4N2 octahedron is severely distorted with a remarkable long Mn‐S bond length of 2.968Å.
Syntheses of Phosphoryl Chloro‐ and Bromofluorides and Crystal Structures of POFCl2 and POF2Cl
Authors: Rovnaník Pavel , Žák Zdirad , Černík Miloš
Published: May 2006

A simple procedure for the preparation of phosphoryl chlorofluorides, POFCl2 and POF2Cl, by chlorination of the appropriate potassium fluorophosphates, K2PO3F and KPO2F2, respectively, with PCl5 is described. The analogous bromination with PBr5 gives POFBr2 and POF2Br. However, due to low yields and high content of impurities, this method is not suitable for the synthesis of the former compound. Both chlorofluorides were crystallized from the melt at low temperatures and their crystal structures were determined by X‐ray diffraction at −153 °C. Distorted tetrahedral molecules of POFCl2 are only weakly associated through intermolecular O···Cl contacts forming infinite chains similarly as in crystalline POCl3. In POF2Cl, however, the chains are formed by the O···P contacts, and an additional P–O···Cl bridging leads to their linkage into a double‐chain structure.
Synthese und Kristallstruktur von Blei(II)‐oxidhalogenid‐Alkoholaten mit unterschiedlichen Verknüpfungsvarianten von Pb4O4‐Heterokubaneinheiten
Authors: Oldag Thorsten , Keller Hans‐Lothar
Published: May 2006

Synthesis and Crystal Structure Determination of Lead(II) Oxide Halide Alcoholates with Different Connectivity of Pb4O4 Heterocubane‐like Subunits

The reaction of red lead(II) oxide (Litharge) and lead(II) halide (Cl− and Br−) with diethylene glycole at a temperature of 180 °C leads to the isotypic compounds [Pb6(C4H8O3)O2Cl6] (1) and [Pb6(C4H8O3)O2Br6] (2). In a similar synthesis with PbI2 as educt at temperature of 160 °C the two modifications β‐[Pb6(C4H8O3)O2I6] (3) and α‐[Pb6(C4H8O3)O2I6] (4) were found, whereas at a reaction temperature of 180 °C [Pb9(C2H4O2)(C4H8O3)O3I8] (5) was surprisingly obtained as product. The X‐ray diffraction data show that at a temperature of 180 °C a splitting of the ether took place. The cited compounds show cubane like subunits built by lead and oxygen atoms. These fragments are connected by alkoholate molecules. In 5 additionally an I6 octahedra centered by lead is observed.