bluuebunny/crossref_metadata_2025 huggingface dataset:
Investments in Global Health: Private and Public Innovation Systems of Essential Pharmaceuticals
Authors: Rantanen Tiina-Riitta
Published: November 2006

In recent years the scope and application of intellectual property rights has been expanded remarkably in the area of medical research and development. This has strengthened the role of the private sector in developing and producing new medicinal drugs. However, medical research is usually close to a pure public good and thus not efficiently produced by private firms. One rationale for the role of the public sector in financing medical research and development involves market failures such as imperfect competition among suppliers and externalities. Another justification for government intervention is inequality — a private market for medical research could be Pareto efficient, providing or even developing no medicines to members of the population who are too poor to pay for them. The main objective of this article is to analyse and compare the effects of private and public innovation systems in medical research and development on global health levels using the theory of (global) public goods as a tool of the analysis.
Long-Term Effect of the Internet-Based Glucose Monitoring System on HbA1c Reduction and Glucose Stability
Authors: Cho Jae-Hyoung , Chang Sang-Ah , Kwon Hyuk-Sang , Choi Yoon-Hee , Ko Seung-Hyun , Moon Sung-Dae , Yoo Soon-Jib , Song Ki-Ho , Son Hyun-Shik , Kim Hee-Seung , Lee Won-Chul , Cha Bong-Yun , Son Ho-Young , Yoon Kun-Ho
Published: November 2006

OBJECTIVE—To investigate the long-term effectiveness of the Internet-based glucose monitoring system (IBGMS) on glucose control in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS—We conducted a prospective, randomized, controlled trial in 80 patients with type 2 diabetes for 30 months. The intervention group was treated with the IBGMS, while the control group made conventional office visits only. HbA1c (A1C) was performed at 3-month intervals. For measuring of the stability of glucose control, the SD value of A1C levels for each subject was used as the A1C fluctuation index (HFI).

RESULTS—The mean A1C and HFI were significantly lower in the intervention group (n = 40) than in the control group (n = 40). (A1C [mean ± SD] 6.9 ± 0.9 vs. 7.5 ± 1.0%, P = 0.009; HFI 0.47 ± 0.23 vs. 0.78 ± 0.51, P = 0.001; intervention versus control groups, respectively). Patients in the intervention group with a basal A1C ≥7% (n = 27) had markedly lower A1C levels than corresponding patients in the control group during the first 3 months and maintained more stable levels throughout the study (P = 0.022). Control patients with a basal A1C <7% (n = 15) showed the characteristic bimodal distribution of A1C levels, whereas the A1C levels in the intervention group remained stable throughout the study with low HFI.

CONCLUSIONS—Long-term use of the IBGMS has proven to be superior to conventional diabetes care systems based on office visits for controlling blood glucose and achieving glucose stability.
Beneficial Associations of Physical Activity With 2-h but Not Fasting Blood Glucose in Australian Adults
Authors: Healy Genevieve N. , Dunstan David W. , Shaw Jonathan E. , Zimmet Paul Z. , Owen Neville
Published: November 2006

OBJECTIVE—We examined the associations of physical activity with fasting plasma glucose (FPG) and with 2-h postload plasma glucose (2-h PG) in men and women with low, moderate, and high waist circumference.

RESEARCH DESIGN AND METHODS—The Australian Diabetes, Obesity and Lifestyle (AusDiab) study provided data on a population-based cross-sectional sample of 4,108 men and 5,106 women aged ≥25 years without known diabetes or health conditions that could affect physical activity. FPG and 2-h PG were obtained from an oral glucose tolerance test. Self-reported physical activity level was defined according to the current public health guidelines as active (≥150 min/week across five or more sessions) or inactive (<150 min/week and/or less than five sessions). Sex-specific quintiles of physical activity time were used to ascertain dose response.

RESULTS—Being physically active and total physical activity time were independently and negatively associated with 2-h PG. When physical activity level was considered within each waist circumference category, 2-h PG was significantly lower in active high–waist circumference women (β −0.30 [95% CI −0.59 to −0.01], P = 0.044) and active low–waist circumference men (β −0.25 [−0.49 to −0.02], P = 0.036) compared with their inactive counterparts. Considered across physical activity and waist circumference categories, 2-h PG levels were not significantly different between active moderate–waist circumference participants and active low–waist circumference participants. Associations between physical activity and FPG were nonsignificant.

CONCLUSIONS—There are important differences between 2-h PG and FPG related to physical activity. It appears that 2-h PG is more sensitive to the beneficial effects of physical activity, and these benefits occur across the waist circumference spectrum.
Serum and Urinary Nitrites and Nitrates and Doppler Sonography in Children With Diabetes
Authors: Savino Alessandra , Pelliccia Piernicola , Schiavone Cosima , Primavera Alessandra , Tumini Stefano , Mohn Angelika , Chiarelli Francesco
Published: November 2006

OBJECTIVE—The aim of the present study was to evaluate serum and urinary nitric oxide (NO) concentrations in children and adolescents with diabetes compared with age-matched healthy control subjects to find out whether Doppler ultrasonography could be used to detect changes in renal resistive indexes (RIs) in children with diabetes and to assess whether there are correlations between these parameters and NO excretion.

RESEARCH DESIGN AND METHODS—We studied 42 children with type 1 diabetes and 41 matched healthy control subjects, both divided into prepubertal or pubertal children. Serum and urinary nitrite and nitrate (NO2−+NO3−) concentrations were evaluated as an index of NO production. Doppler ultrasonographic registration of intrarenal RI was performed.

RESULTS—Compared with healthy control subjects, children with diabetes had significantly increased concentrations of serum (30.26 ± 6.52 vs. 24.47 ± 7.27 mmol/l, P = 0.001) and urinary NO2−+NO3− (345.07 ± 151.35 vs. 245.86 ± 80.25 mmol/l, P = 0.002); the same was true for Doppler RI values (0.64 ± 0.03 vs. 0.60 ± 0.04, P = 0.035). This occurs in both prepubertal and the pubertal children. A significant positive correlation was found between serum and urinary NO2−+NO3− levels (P = 0.002, r = 0.374). Serum NO2−+NO3− concentrations also correlated positively with Doppler RI (P = 0.032, r = 0.262) and HbA1c (A1C) (P = 0.004, r = 0.329); urinary NO2−+NO3− concentrations correlated positively with A1C (P = 0.001, r = 0.394). Doppler RI correlated positively with A1C (P = 0.000, r = 0.424).

CONCLUSIONS—This study demonstrates that in children with diabetes, chronic hyperglycemia may act through a mechanism that involves increased NO production and/or action and contributes to generating intrarenal hemodynamic abnormalities, which are detectable by Doppler ultrasonography even in early diabetic nephropathy.
Efficacy and Safety of the Dipeptidyl Peptidase-4 Inhibitor Sitagliptin Added to Ongoing Metformin Therapy in Patients With Type 2 Diabetes Inadequately Controlled With Metformin Alone
Authors: Charbonnel Bernard , Karasik Avraham , Liu Ji , Wu Mei , Meininger Gary ,   for the Sitagliptin Study 020 Group
Published: November 2006

OBJECTIVE—The efficacy and safety of the dipeptidyl peptidase-4 inhibitor, sitagliptin, added to ongoing metformin therapy, were assessed in patients with type 2 diabetes who had inadequate glycemic control (HbA1c [A1C] ≥7 and ≤10%) with metformin alone.

RESEARCH DESIGN AND METHODS—After a screening diet/exercise run-in period, a metformin dose titration/stabilization period, and a 2-week, single-blind, placebo run-in period, 701 patients, aged 19–78 years, with mild to moderate hyperglycemia (mean A1C 8.0%) receiving ongoing metformin (≥1,500 mg/day) were randomly assigned to receive the addition of placebo or sitagliptin 100 mg once-daily in a 1:2 ratio for 24 weeks. Patients exceeding specific glycemic limits were provided rescue therapy (pioglitazone) until the end of the study. The efficacy analyses were based on an all-patients-treated population using an ANCOVA and excluded data obtained after glycemic rescue.

RESULTS—At week 24, sitagliptin treatment led to significant reductions compared with placebo in A1C (−0.65%), fasting plasma glucose, and 2-h postmeal glucose. Fasting insulin, fasting C-peptide, fasting proinsulin-to-insulin ratio, postmeal insulin and C-peptide areas under the curve (AUCs), postmeal insulin AUC–to–glucose AUC ratio, homeostasis model assessment of β-cell function, and quantitative insulin sensitivity check index were significantly improved with sitagliptin relative to placebo. A significantly greater proportion of patients achieved an A1C <7% with sitagliptin (47.0%) than with placebo (18.3%). There was no increased risk of hypoglycemia or gastrointestinal adverse experiences with sitagliptin compared with placebo. Body weight decreased similarly with sitagliptin and placebo.

CONCLUSIONS—Sitagliptin 100 mg once-daily added to ongoing metformin therapy was efficacious and well tolerated in patients with type 2 diabetes who had inadequate glycemic control with metformin alone.
Transforming Growth Factor-β in Human Diabetic Nephropathy
Authors: Langham Robyn G. , Kelly Darren J. , Gow Renae M. , Zhang Yuan , Cordonnier Daniel J. , Pinel Nicole , Zaoui Phillipe , Gilbert Richard E.
Published: November 2006

OBJECTIVE—Studies in rodent models have suggested that reduction in renal transforming growth factor (TGF)-β1 may underlie the renoprotective effects of the renin-angiotensin system (RAS) blockade. However, the role of the RAS blockade in abrogating TGF-β in human disease is unknown. Accordingly, we sought to examine TGF-β gene expression and biological activity in human renal biopsies, before and after ACE inhibition.

RESEARCH DESIGN AND METHODS—RNA was extracted from renal biopsies taken from participants in the Diabiopsies study, a randomized controlled 2-year trial of 4 mg/day perindopril versus placebo that reported a reduction in proteinuria and cortical matrix expansion in type 2 diabetic nephropathy. Biopsies taken at study entry and at 2 years were obtained in 12 patients (6 placebo and 6 taking perindopril). TGF-β1 and its receptor mRNA were quantified by real-time PCR, and its biological activity was assessed by examining the activation of its intracellular signaling pathway (phosphorylated Smad2) and the expression TGF-β–inducible gene H3 (βig-H3).

RESULTS—At baseline, TGF-β1 expression was similar in both placebo- and perindopril-treated groups and was unchanged over a 2-year period in biopsies of placebo-treated subjects. In contrast, perindopril treatment led to a substantial diminution in TGF-β1 mRNA (mean 83% reduction, P < 0.05). Phosphorylated Smad2 immunolabeling and βig-H3 mRNA were similarly reduced with ACE inhibition (P < 0.05) but unchanged in the placebo group. No differences were noted in the gene expression of TGF-β receptor II in biopsies of either placebo- or perindopril-treated subjects.

CONCLUSIONS—This study demonstrates that over a 2-year period, treatment with perindopril in patients with type 2 diabetes and nephropathy leads to a reduction in both renal TGF-β1 gene expression and its downstream activation.
Plasma Metallothionein Antibody, Urinary Cadmium, and Renal Dysfunction in a Chinese Type 2 Diabetic Population
Authors: Chen Liang , Lei Lijian , Jin Taiyi , Nordberg Monica , Nordberg Gunnar F.
Published: November 2006

OBJECTIVE—It has been reported that diabetes may increase the risk of cadmium-induced kidney damage. The presence of metallothionein antibody (MT-Ab) increased the susceptibility for tubular damage among cadmium workers. This study focused on the relationships between levels of MT-Ab, urinary cadmium, and kidney function in a Chinese type 2 diabetic population.

RESEARCH DESIGN AND METHODS—A cross-sectional study was performed on 229 type 2 diabetic patients (92 men and 137 women) who were recruited from two community centers in one district of Shanghai City in China. Information was obtained from interviews, health records, and blood and urine samples.

RESULTS—Levels of the tubular biomarker β2-microglobulin increased significantly when the levels of MT-Ab and urinary cadmium were elevated in male and female subjects; in contrast, the levels of urinary albumin, a glomerular biomarker, did not display such a pattern. After adjusting for potential confounding covariates, logistic regression showed that the odds ratios (ORs) of tubular dysfunction increased upon 1) increasing the MT-Ab concentration from a low to high level (OR 5.56 [95% CI 2.25–13.73]) and 2) increasing the level of urinary cadmium from <1 to ≥1 μg/g creatinine (3.34 [1.17–9.53]); the OR of patients currently smoking was 3.51 (1.14–10.80) relative to that of those who had never smoked.

CONCLUSIONS—This study proves that the presence of MT-Ab can potentiate tubular dysfunction among diabetic subjects and that patients with high MT-Ab levels are more prone to development of tubular damage.
Prediction of Postprandial Glycemic Exposure
Authors: Cohen Ohad , Basu Rita , Bock Gerlies , Dalla Man Chiara , Campioni Marco , Basu Ananda , Toffolo Gianna , Cobelli Claudio , Rizza Robert A.
Published: November 2006

OBJECTIVE—To determine the best predictors of total postprandial glycemic exposure and peak glucose concentrations in nondiabetic humans.

RESEARCH DESIGN AND METHODS—Data from 203 nondiabetic volunteers who ingested a carbohydrate-containing mixed meal were analyzed.

RESULTS—Fasting glucose and insulin concentrations were poor predictors of postprandial glucose area above basal (R2 = ∼0.07, P < 0.001). The correlation was stronger for 2-h glucose concentration (R2 = 0.55, P < 0.001) and improved slightly but significantly (P < 0.001) with the addition of fasting glucose, insulin, age, sex, and body weight to the model (r2 = 0.58). The 2-h glucose concentration also predicted the peak glucose concentration (R2 = 0.37, P < 0.001) with strength of the prediction increasing (P < 0.001) modestly with the addition of fasting glucose, insulin, age, sex, and body weight to the model (R2 = 0.48, P < 0.001). On the other hand, addition of measures of body function and composition did not improve prediction of total glycemic exposure or peak glucose concentration.

CONCLUSIONS—Isolated measures of fasting or 2-h glucose concentrations alone or in combination with more complex measures of body composition and function are poor predictors of postprandial glycemic exposure or peak glucose concentration. This may explain, at least in part, the weak and at times inconsistent relationship between these parameters and cardiovascular risk.
Relationship of Fasting and Hourly Blood Glucose Levels to HbA1c Values
Authors: Garg Satish , Jovanovic Lois
Published: November 2006

OBJECTIVE—In this study, we evaluated the safety and efficacy of 7-day transcutaneous, real-time, continuous glucose monitoring (CGM) in subjects with insulin-requiring diabetes.

RESEARCH DESIGN AND METHODS—Eighty-six subjects were enrolled at five U.S. centers. Subjects wore a sensor inserted under the skin of the abdomen for 7 days during each of three consecutive periods. Data were blinded during period 1 and unblinded during periods 2 and 3.

RESULTS—Of the 6,811 matched self-monitoring of blood glucose to sensor values prospectively analyzed, 97.2% fell in the Clarke error grid zones A and B, and median absolute relative difference was 11.4%. After unblinding, subjects reduced time spent at <55 mg/dl by 0.3 h/day, reduced time spent at >240 mg/dl by 1.5 h/day, and increased time in the target zone (81–140 mg/dl) by 1.4 h/day (P < 0.05 for all three comparisons). Improvements were seen in both types 1 and 2 diabetes and with use of both multiple daily injections and continuous subcutaneous insulin infusion. Modal day graphs were generated in six groups of subjects based on HbA1c (A1C) (≤6, 6–7, 7–8, 8–9, 9–10, and >10%). Mean glucose levels from midnight to 7:00 a.m. (fasting and dawn phenomenon periods) were only normal for subjects with A1C ≤6%. All other groups were hyperglycemic during this and all periods. Reductions in overall mean glucose were achieved for the four highest A1C groupings with unblinded device use.

CONCLUSIONS—This is the first report of a real-time, transcutaneous glucose sensor that functioned for 7 days. The use of CGM in the unblinded phase resulted in improvements in target-range glycemia across all A1C values.
Functional defects in adenylyl cyclase signaling mechanisms of insulin and relaxin in skeletal muscles of rat with streptozotocin type 1 diabetes
Authors: Shpakov Alexander , Kuznetsova Ludmila , Plesneva Svetlana , Kolychev Alexander , Bondareva Vera , Chistyakova Oksana , Pertseva Marianna
Published: November 2006

Functional disturbance in the novel adenylyl cyclase signaling mechanism (ACSM) of insulin and relaxin action in rat streptozotocin (STZ) type I diabetes was studied on the basis of the authors’ conception of molecular defects in hormonal signaling systems as the main causes of endocrine diseases. Studying the functional state of molecular components of the ACSM and the mechanism as a whole, the following changes were found in the skeletal muscles of diabetic rats compared with control animals: 1) increase of insulin receptor binding due to an increase in the number of insulin binding sites with high and low affinity; 2) increase of the basal adenylyl cyclase (AC) activity and the reduction of AC-activating effect of non-hormonal agents (guanine nucleotides, sodium fluoride, forskolin); 3) reduction of ACSM response to stimulatory action of insulin and relaxin; 4) decrease of the insulin-activating effect on the key enzymes of carbohydrate metabolism, glycogen synthase and glucose-6-phosphate dehydrogenase. Hence, the functional activity of GTP-binding protein of stimulatory type, AC and their functional coupling are decreased during experimental type 1 diabetes that leads to the impairment of the transduction of insulin and relaxin signals via ACSM.
Synthesis of Indolizines and Benzoindolizines by Annulation of Donor‐Acceptor Cyclopropanes with Electron‐Deficient Pyridines and Quinolines
Authors: Morra Nicholas A. , Morales Christian L. , Bajtos Barbora , Wang Xin , Jang Hyosook , Wang Jian , Yu Ming , Pagenkopf Brian L.
Published: November 2006

The formal [3+2] dipolar cycloaddition (or annulation) of donor‐acceptor cyclopropanoate esters with pyridines and 5‐nitroquinoline is reported. Electron‐deficient pyridine dipolarophiles (R=CN, CO2Et, COMe) participate in the annulation whereas electron rich species do not. The product 2,3‐dihydroindolizines undergo rapid autooxidation, and the X‐ray structures for two of the aromatic products are reported.
Iridium‐Catalyzed Enantioselective [2+2+2] Cycloaddition of Diynes and Monoalkynes for the Generation of Axial Chiralities
Authors: Shibata Takanori , Arai Yoshikazu , Takami Kyoko , Tsuchikama Kyoji , Fujimoto Takayoshi , Takebayashi Satoshi , Takagi Kentaro
Published: November 2006

A highly enantioselective intermolecular [2+2+2] cycloaddition of alkynes was catalyzed by a chiral iridium complex. Symmetrical and unsymmetrical diynes, and monoalkynes possessing functional group(s) were subjected to the reaction and various types of axially chiral compounds possessing biaryl skeletons were obtained in good to excellent enantiomeric excesses.
Stereoselective Synthesis of Multifunctionalized 1,2,4‐Triazolidines by a Ruthenium Porphyrin‐Catalyzed Three‐Component Coupling Reaction
Authors: Wang Ming‐Zhong , Xu Hai‐Wei , Liu Yungen , Wong Man‐Kin , Che Chi‐Ming
Published: November 2006

Multifunctionalized 1,2,4‐triazolidines have been synthesized by a ruthenium porphyrin‐catalyzed three‐component coupling reaction. In a one‐pot reaction, ruthenium porphyrins catalyzed the in situ generation of azomethine ylides from α‐diazo esters and imines. Stereoselective 1,3‐dipolar cycloaddition reactions of the azomethine ylides with dialkyl azodicarboxylates gave the corresponding 1,2,4‐triazolidines in good yields (up to 85 %). Using chiral 8‐phenylmenthanol α‐diazo ester as the carbenoid source, chiral 1,2,4‐triazolidines have been obtained with good diastereoselectivity (up to 84 % de). Some of the 1,2,4‐triazolidines exhibited good cytotoxicity against human nasopharyngeal carcinoma (SUNE1) (IC50=10.4 μM) and human cervical carcinoma (Hela) (IC50=10.7 μM) cell lines.
Recent Advances in the Catalytic Pauson–Khand‐Type Reaction
Authors: Shibata Takanori
Published: November 2006

The Pauson–Khand‐type reaction is formally a [2+2+1] cycloaddition involving an alkyne, an alkene and carbon monoxide catalyzed or mediated by transition metal complexes. This review focuses on the catalytic reaction and describes the recent research on the Pauson–Khand‐type reaction.
Enantioselective Cyclopropanation with TADDOL‐Derived Phosphate Ligands
Authors: Voituriez Arnaud , Charette André B.
Published: November 2006

The synthesis of new chiral TADDOL‐derived phosphate ligands is described. The ligands were efficiently synthesized on a multi‐gram scale in three steps starting from the readily available corresponding TADDOL and were fully characterized. An X‐ray structure was obtained and compared to known BINOL‐phosphates. Their use in the asymmetric Simmons–Smith cyclopropanation of both functionalized and unfunctionalized olefins gave the desired cyclopropanes in good yields and good to moderate enantioselectivities.
Copper Salt‐Catalyzed Azide‐[3 + 2] Cycloadditions of Ynamides and Bis‐Ynamides
Authors: Zhang Xuejun , Li Hongyan , You Lingfeng , Tang Yu , Hsung Richard P.
Published: November 2006

A one‐pot synthesis of amide‐substituted triazoles from alkyl bromides and ynamides is described here along with syntheses of novel bis‐ynamides and their applications in [3+2] cycloadditions with azides to construct unique bis‐triazoles.
A correlation for the diameter of electrospun polymer nanofibers
Authors: Helgeson Matthew E. , Wagner Norman J.
Published: November 2006

A rational method to control morphology of polymer nanofibers produced by electrospinning is developed using dimensional analysis of the electrospinning process. The analysis is validated against data sets from the literature, which provides an empirical correlation between fiber size, controllable operating conditions, and measurable spinning solution properties. A stable jet operating regime is identified for which scaling of dimensionless groups is presented. Deviations from this scaling are qualitatively consistent with capillary instability of the electrospinning jet, for which a beaded fiber morphology is obtained. The results provide criteria for designing and controlling electrospinning of polymer solutions and resulting nanofiber morphology. © 2006 American Institute of Chemical Engineers AIChE J, 2007
Fitness and extra‐group reproduction in male Verreaux's sifaka: An analysis of reproductive success from 1989–1999
Authors: Lawler Richard R.
Published: November 2006

Adult males in social groups often compete with other male group members for access to adult females. In some primate species, males also seek mating opportunities in neighboring social groups. Such extra‐group fertilizations (EGFs) provide an additional source of variation in male fitness. This additional component of fitness provided by EGFs must be incorporated into analyses that investigate sources of variation in male lifetime reproductive success. In this study, a model is analyzed in which male fitness over a 10‐year sample period is decomposed into additive and multiplicative variance and covariance components. The data come from an ongoing study of a wild population of Verreaux's sifaka (Propithecus verreauxi verreauxi) located at Beza Mahafaly Special Reserve, Southwest Madagascar. Paternity and demographic data for 134 males are used to decompose male fitness into the following three multiplicative components: reproductive lifespan during sample period, fertility, and offspring survival. These multiplicative components are estimated for males reproducing within their resident groups plus (i.e., the additive portion) for males reproducing in neighboring social groups. The analysis shows that variation in fertility makes the largest contribution to variation in total fitness, followed by variation in amount of time spent in sample period (which is a proxy of total reproductive lifespan) and variation in offspring survival. EGFs contribute an important source of variation to male fitness, and numerous factors enhance the opportunities for EGFs in male sifaka. These include female choice, a high degree of home range overlap, and a limited mating season. Am J Phys Anthropol, 2007. © 2006 Wiley‐Liss, Inc.
Gold‐Katalyse
Authors: Hashmi A. Stephen K. , Hutchings Graham J.
Published: November 2006

Die Katalyse durch Gold ist schnell ein “heißes Thema” der Chemie geworden – fast wöchentlich werden neue Entdeckungen gemacht. Gold ist gleichermaßen als heterogener wie auch als homogener Katalysator aktiv, und im folgenden Aufsatz wollen wir diese beiden Facetten gemeinsam präsentieren, um so die vielfältigen Möglichkeiten der Gold‐Katalyse darzulegen. Die neuesten Entdeckungen werden im historischen Kontext diskutiert, Hauptziel ist aber, die neuen Optionen aufzuzeigen, die Gold‐Katalysatoren dem Synthesechemiker bieten – besonders auf den Gebieten der Redoxreaktionen und nucleophilen Additionen an π‐Systeme. Oft erweist sich Gold sogar als guter Katalysator für zuvor unbekannte Reaktionen, und in diesem Bereich gibt es mit Sicherheit noch viel zu entdecken.
Titelbild: Total Synthesis and Antitumor Activity of ZK‐EPO: The First Fully Synthetic Epothilone in Clinical Development (Angew. Chem. 47/2006)
Authors: Klar Ulrich , Buchmann Bernd , Schwede Wolfgang , Skuballa Werner , Hoffmann Jens , Lichtner Rosemarie B.
Published: November 2006

Die Natur ist ein brillanter Architekt für das Design von Verbindungen mit interessanten biologischen Eigenschaften. Epothilon B, ein Metabolit von Myxobakterien (Fruchtkörper im Hintergrund), fungierte als Leitstruktur zur Entwicklung eines möglichen Tumortherapeutikums. Eine Optimierung führte zu ZK‐EPO (unten) als Kandidat für die klinische Entwicklung. ZK‐EPO wird nicht durch multiwirkstoffresistente Effluxmechanismen erkannt und hat ein verbessertes Therapiefenster. U. Klar et al. beschreiben auf S. 8110 ff. die Totalsynthese von ZK‐EPO aus einfachen Verbindungen (blau).
Natural fiber suspensions in thermoplastic polymers. I. Analysis of fiber damage during processing
Authors: Terenzi Andrea , Kenny José M. , Barbosa Silvia E.
Published: November 2006

The final properties of the composites materials are strongly dependent on the residual aspect ratio, orientation, and distribution of the fibers, which are determined by the processing conditions. Present work is a systematic study of the influence of natural fiber concentration on its damage during all the steps involved in the composite compounding. The system under study is cellulose fiber‐reinforced polypropylene. The fiber geometrical parameters—length, diameter, and aspect ratio—are measured, and their statistical distributions are assessed for different concentrations. It is found that the higher the fiber concentration, the lower the fiber damage. These results evidence a difference in behavior between the damage of flexible natural fiber and rigid ones. The results are analyzed in terms of fiber concentration regimes, fiber–fiber interaction, flexibility, and entanglements. Two competitive mechanisms of the fiber interaction are proposed for explaining the fiber damage behavior during the flow of the flexible natural fiber suspensions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2501–2506, 2007
Effect of organosilica isomers on the interfacial interaction in polyimide/aromatic organosilica hybrids
Authors: Choi Seokwon , Kim Youngkyoo , Kim Il , Ha Chang‐Sik
Published: November 2006

We report the effect of organosilica precursor isomers on the interfacial interaction between polyimide and organosilica in polyimide/organosilica hybrid composite films. Poly(4,4′‐oxydianiline biphenyltetracarboxamic acid) (BPDA‐ODA PAA) was used as the polyimide precursor, while the organosilica was made using o‐substituted, m‐substituted, and p‐substituted phenyl organosilica precursor isomers. For the preparation of precursor hybrid films, BPDA‐ODA PAA and organosilica precursors were mixed and then the organosilica precursors were converted to corresponding organosilica via sol–gel process. Finally, these precursor films were converted to corresponding polyimide/organosilica hybrid films by the thermal imidization of BPDA‐ODA PAA, which results in poly(4,4′‐oxydianiline biphenyltetracarboximide) (BPDA‐ODA PI). The polyimide/organosilica hybrid films were characterized using three distinctive nuclear magnetic resonance spectroscopies (1H NMR, 13C‐CPMAS‐NMR, and 29Si‐MAS‐NMR), wide‐angle X‐ray diffraction (WAXD), small‐angle X‐ray scattering (SAXS), and peel strength measurement. We found that the m‐substituted phenyl organosilica shows poorer interfacial interaction with BPDA‐ODA PI than do the o‐ or p‐substituted phenyl organosilicas. It was observed, however, that the peel strength of the hybrid films against an aluminum substrate increased with increasing contents of organosilicas, regardless of the nature of the organosilica isomers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2507–2513, 2007
Influence of alkyl chain length on the gelation mechanism of thermoreversible gels of regioregular poly(3‐alkyl thiophenes) in xylene
Authors: Malik Sudip , Nandi Arun K.
Published: November 2006

The gelation rates of poly(3‐alkyl thiophenes) (P3AT) are strongly dependent on the pendent alkyl chain length. Poly(3‐hexyl thiophene (P3HT) gels at higher isothermal temperatures than that of poly(3‐dodecyl thiophene), (P3DDT). Gelation rate has been expressed as a combination of a temperature dependent function f(T) and a concentration dependent function (φn); φ being the reduced overlapping concentration of P3AT. From the slope of double logarithmic plot of gelation rate and φ, n values are calculated to be 0.52 and 0.60 for P3HT and P3DDT, respectively. These values are close to the value of percolation exponent β (0.45) for three‐dimensional lattice; so both the gels may approximately obey three dimensional percolation model. The f(T) of gelation rate consists of two steps (i) coil‐to‐rod transformation followed by (ii) fibrillar crystallization. The coil‐to‐rod transition is accompanied by a red shift in the π–π* transition band in UV–vis spectra. Flory and Weaver theory is used to understand the coil‐to‐rod transformation process. The theory of fibrillar crystallization extended to dilute solution has been employed to understand the crystallization process. The results clearly indicate that the activation energy of conformational change (ΔF) is higher for P3DDT than that of P3HT. But the free energy change for the formation of critical size nucleus (Δ G) is lower for P3DDT than that of P3HT. A comparison of ΔF and Δ G values indicate conformational ordering is the rate‐determining step for P3AT with dodecyl substituent whereas crystallization is the rate‐determining step for P3AT with hexyl substituent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2528–2537, 2007
Copolymerization and blending of poly(phthalazinone ether ketone)s to improve their melt processability
Authors: Xia Jiqiang , Zhang Jun , Liao Gongxiong , Jian Xigao
Published: November 2006

The melt processability of phthalazinone‐containing poly(aryl ether)s (PAEs) was improved through copolymerization and blending. Poly(phthalazinone ether ketone) (PPEK) copolymers containing phthalazinone and bisphenol‐A (BPA) moieties were synthesized through nucleophilic substitution polycondensation. The PPEK copolymers exhibited high glass transition temperatures, excellent thermooxidative properties, good mechanical properties and improved solubility, all of which can be tailored by changing the molar ratio of phthalazinone to bisphenol monomers. The rheological investigation indicated that the incorporation of the flexible BPA moiety into the main chain lowered the melt viscosity of the copolymers. To improve the melt processability further, polymer blends of a PPEK copolymer/polycarbonate (PC) were prepared. The results suggested that blending is an effective approach for improving the melt processability of phthalazinone‐containing PAEs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2575–2580, 2007
Effects of antiplasticization on the thermal, volumetric, and transport properties of polyethersulfone
Authors: Vidotti S. E. , Chinellato A. C. , Pessan L. A.
Published: November 2006

The aim of this work was to study the effects of the addition of low molar mass additives such as N‐phenyl‐2‐naphthylamine (PNA) and hexafluoro‐bisphenol‐A (HFBPA) on the volumetric, thermal and transport properties of polyethersulfone (PES). The additive incorporation resulted in changes in molecular mobility and properties of the glassy PES matrix associated with antiplasticization. The changes in molecular mobility were accompanied by reductions in water vapor permeability of the PES of up to 93% for 30 wt % incorporation of PNA and of up to 70% for the addition of 20 wt % of HFBPA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2627–2633, 2007
Pervaporation separation of sodium alginate/chitosan polyelectrolyte complex composite membranes for the separation of water/alcohol mixtures: Characterization of the permeation behavior with molecular modeling techniques
Authors: Kim Sang‐Gyun , Lee Ki‐Sub , Lee Kew‐Ho
Published: November 2006

Polyelectrolyte complex (PEC) membranes were prepared by the complexation of protonated chitosan with sodium alginate doped on a porous, polysulfone‐supporting membrane. The pervaporation characteristics of the membranes were investigated with various alcohol/water mixtures. The physicochemical properties of the permeant molecules and polyion complex membranes were determined with molecular modeling methods, and the data from these methods were used to explain the permeation of water and alcohol molecules through the PEC membranes. The experimental results showed that the prepared PEC membranes had an excellent pervaporation performance in most aqueous alcohol solutions and that the selectivity and permeability of the membranes depended on the molecular size, polarity, and hydrophilicity of the permeant alcohols. However, the aqueous methanol solutions showed a permeation behavior different from that of the other alcohol solutions. Methanol permeated the prepared PEC membranes more easily than water even though water molecules have stronger polarity and are smaller than methanol molecules. The experimental results are discussed from the point of view of the physical properties of the permeant molecules and the membranes in the permeation state. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2634–2641, 2007
Preparation and drug‐release behavior of 5‐fluorouracil‐loaded poly(lactic acid–4‐hydroxyproline–polyethylene glycol) amphipathic copolymer nanoparticles
Authors: Duan Jiufang , Du Jie , Zheng Yu Bin
Published: November 2006

Poly(lactic acid–4‐hydroxyproline–polyethylene glycol) (PLA–Hpr–PEG) was synthesized via melt copolymerization with stannous chloride as a catalyst activated by a proton acid. Copolymers with different poly(ethylene glycol) (PEG) concentrations (0.1, 0.5, 1, and 5 wt %) were synthesized and exhibited moderate molecular weights (weight‐average molecular weight = 9705–13,600 g/mol) and reasonable molecular weight distributions (weight‐average molecular weight/number‐average molecular weight = 1.35– 1.66). The structure of the polymers was verified with infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The nanoparticles were made by the nanoprecipitation method with PLA–Hpr–PEG. The size and size distribution of the nanoparticles were investigated with laser light scattering, and the surface morphology of the nanoparticles was investigated with transmission electron microscopy. The drug encapsulation efficiency and drug loading content were measured with ultraviolet absorption spectroscopy. The effects of various formulation parameters were evaluated. The prepared nanoparticles were spherical and greater than 100 nm in size. The drug loading content and encapsulation efficiency were greatly influenced by the amount of the copolymer and the volume of the solvent. The PEG content in the polymer could affect the release of drugs from the PLA–Hpr–PEG nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2654–2659, 2007
Investigation of the polycarbonate/crushed‐rubber‐particle interphase by nanoindentation
Authors: Bourmaud A. , Grohens Y. , Zribi K. , Feller J. F.
Published: November 2006

Nanoindentation tests were carried out to determine the nanomechanical characteristics of recycled polycarbonate (PC)/crushed‐rubber blends. Both the modulus and hardness of the matrix, particles, and PC/rubber interphase were obtained. Different blends with untreated, flamed, and washed rubber particles were characterized. The results proved the good recyclability of PC. Indentations performed in the PC matrix showed that the rubber acted as a plasticizer for the PC matrix, probably because of a diffusion of free rubber chains. This plasticizing effect was accentuated by flamed rubber particles in the blends. The results showed that flame and methanol treatments modified the morphology of the rubber particles. These treatments induced a significant increase in the nanomechanical properties of the rubber particles. In the interface region between the PC matrix and rubber particles, a gradual change in the mechanical properties was confirmed. Profiles of the interface modulus and hardness helped to determine the interface width according to the particle treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2687–2694, 2007
Knee joint loading differs in individuals with mild compared with moderate medial knee osteoarthritis
Authors: Thorp Laura E. , Sumner D. Richman , Block Joel A. , Moisio Kirsten C. , Shott Susan , Wimmer Markus A.
Published: November 2006

Objective

To compare the knee joint loading patterns in individuals with differing radiographic grades of knee osteoarthritis (OA) for characterization of the mechanical implications of different structural states, and to compare the knee adduction angular impulse, a measure of gait complementary to the commonly used peak knee adduction moment.

Methods

Asymptomatic subjects (those without knee OA) having a Kellgren/Lawrence (K/L) radiographic severity grade of 0 or 1 (n = 28) and subjects with symptomatic knee OA having K/L grades of 2 (n = 66) or 3 (n = 23) were recruited. Gait analysis was used to calculate the peak external knee adduction moment and the external knee adduction angular impulse for the whole stance and for the 4 subdivisions of stance.

Results

Both the peak knee adduction moment and the knee adduction angular impulse increased with K/L radiographic grade (P < 0.05). However, only the knee adduction angular impulse differed between subjects with moderate (grade 3) and those with mild (grade 2) radiographic knee OA (P < 0.05).

Conclusion

The differences between mild and moderate symptomatic radiographic knee OA are not only structural but also functional, based on the magnitude of load in the medial knee joint. Moreover, knee adduction angular impulse provides additional information beyond that available from the peak knee adduction moment, and may therefore be an important gait parameter to include in OA research. These findings are important for our understanding of the pathophysiologic mechanisms of OA.
Automatic cognitive style identification of digital library users for personalization
Authors: Frias‐Martinez Enrique , Chen Sherry Y. , Liu Xiaohui
Published: November 2006

Digital libraries have become one of the most important Web services for information seeking. One of their main drawbacks is their global approach: In general, there is just one interface for all users. One of the key elements in improving user satisfaction in digital libraries is personalization. When considering personalizing factors, cognitive styles have been proved to be one of the relevant parameters that affect information seeking. This justifies the introduction of cognitive style as one of the parameters of a Web personalized service. Nevertheless, this approach has one major drawback: Each user has to run a time‐consuming test that determines his or her cognitive style. In this article, we present a study of how different classification systems can be used to automatically identify the cognitive style of a user using the set of interactions with a digital library. These classification systems can be used to automatically personalize, from a cognitive‐style point of view, the interaction of the digital library and each of its users.
Models for the X‐ray spectra and variability of luminous accreting black holes
Authors: Malzac J. , Merloni A. , Suebsuwong T.
Published: November 2006

The X‐ray spectra of luminous Seyfert 1 galaxies often appear to be reflection dominated. In a number of Narrow Line Seyfert 1 (NLS1) galaxies and galactic black holes in the very high state, the variability of the continuum and of the iron line are decoupled, the reflected component being often much less variable than the continuum. These properties have been interpreted as effects of gravitational light bending. In this framework, we present detailed Monte‐Carlo simulations of the reflection continuum in the Kerr metric. These calculations confirm that the spectra and variability behaviour of these sources can be reproduced by the light bending model. As an alternative to the light bending model, we show that similar observational properties are expected from radiation pressure dominated discs subject to violent clumping instabilities and, as a result, have a highly inhomogeneous two‐phase structure. In this model, most of the observed spectral and variability features originate from the complex geometrical structure of the inner regions of near‐Eddington accretion flows and are therefore a signature of accretion physics rather than general relativity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The iron emission line complex of MCG‐5‐23‐16: the long XMMNewton look
Authors: Braito V. , Reeves J. N. , Dewangan G. , George I. , Griffiths R. , Markowitz A. , Nandra K. , Porquet D. , Ptak A. , Turner T. J. , Yaqoob T. , Weaver K.
Published: November 2006

We present the results of the simultaneous XMM‐Newton and Chandra observations of the bright Seyfert 1.9 galaxy MCG–5‐23‐16, which is one of the best known examples of a relativistically broadened iron Kα line. We find that: a) the soft X‐ray emission is likely to be dominated by photoionized gas, b) the complex iron emission line is best modelled with a narrow and a broad component with a FWHM ∼44000 km/s. This latter component has an EW ∼50 eV and its profile is well described with an emission line mainly originating from the accretion disk a few tens of gravitational radii from the central black hole and viewed with an inclination angle ∼40°. We found evidence of a possible sporadic absorption line at ∼7.7 keV which, if associated with Fe XXVI Kα resonance absorption, is indicative of a possible high velocity (v ∼ 0.1c) outflow. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cover Picture: A Cyclam Core Dendrimer Containing Dansyl and Oligoethylene Glycol Chains in the Branches: Protonation and Metal Coordination (Chem. Eur. J. 35/2006)
Authors: Branchi Barbara , Ceroni Paola , Bergamini Giacomo , Balzani Vincenzo , Maestri Mauro , van Heyst Jeroen , Lee Sang‐Kyu , Luppertz Friedhelm , Vögtle Fritz
Published: November 2006

A most important feature of dendrimer chemistry is the possibility to insert selected chemical units in predetermined sites of the dendritic structure. In their Full Paper on page 8926 ff., P. Ceroni, F. Vögtle et al. discuss how it is possible to design and construct dendrimers that can perform complex functions that derive from the integration of the specific properties of the constituent moieties. The cover picture was created by Fausto Puntoriero.
The Crystal Structure, Thermal Behavior and Ionic Conductivity of a Novel Lithium Gadolinium Polyphosphate LiGd(PO3)4.
Authors: Ettis Hasna , Naili Houcine , Mhiri Tahar
Published: November 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Oxoneptunium(V) as Part of the Framework of a Polyoxometalate.
Authors: Copping Roy , Gaunt Andrew J. , May Iain , Sharrad Clint A. , Collison David , Helliwell Madeleine , Fox O. Danny , Jones Chris J.
Published: November 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Rare Earth—Copper—Magnesium Compounds LnCu9Mg2 (Ln: Y, La—Nd, Sm—Ho, Yb) with Ordered CeNi3‐Type Structure.
Authors: Solokha P. , Pavlyuk V. , Saccone A. , De Negri S. , Prochwicz W. , Marciniak B. , Rozycka‐Sokolowska E.
Published: November 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Behavior of Benzoins and Hydroxy Ketones in Acid Medium. Part 2. Reactions of 1,2‐Bis(2,5‐dimethyl‐3‐thienyl)‐2‐hydroxyethan‐1‐one with N,S‐Binucleophiles in Trifluoroacetic Acid.
Authors: Krayushkin M. M. , Lichitskii B. V. , Mikhalev A. P. , Nabatov B. V. , Dudinov A. A. , Ivanov S. N.
Published: November 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Oxidative Ring Opening of 2,5‐Diarylfurans by Selectfluor®.
Authors: Blank Stephen J. , Stephens Chad E.
Published: November 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Comparison and Evaluation of Two Immobilization Techniques for Task Specific Onium Salts (TSOS) in Mizoroki‐Heck Cross Coupling Reactions.
Authors: Brochwitz Christoph , Feldhoff Armin , Kunz Ulrich , Vaultier Michel , Kirschning Andreas
Published: November 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Diastereoselective Cobalt‐Catalyzed Reductive Aldol Cyclizations Using Diethylzinc as the Stoichiometric Reductant.
Authors: Lam Hon Wai , Joensuu Pekka M. , Murray Gordon J. , Fordyce Euan A. F. , Prieto Oscar , Luebbers Thomas
Published: November 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Chiral‐Bridged Aminotroponiminate Complex of Lutetium as Catalyst for the Asymmetric Hydroamination.
Authors: Meyer Nils , Zulys Agustino , Roesky Peter W.
Published: November 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Reaction of 4‐Substituted Thiosemicarbazides with (2,4,7‐Trinitro‐9H‐fluoren‐9‐ylidene)propanedinitrile.
Authors: Hassan Alaa A. , Ibrahim Yusria R. , Shawky Ahmed M. , Doepp Dietrich
Published: November 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.