bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, Characterization, and Properties of Some Copper(II) Complexes of 2‐Pyridineformamide Thiosemicarbazone (HAm4DH)
Authors: del Carmen Aguirre María , Borrás Joaquín , Castiñeiras Alfonso , García‐Monteagudo José M. , García‐Santos Isabel , Niclós Juan , West Douglas X.
Published: January 2006

Reactions between different copper(II) salts and 2‐pyridineformamide thiosemicarbazone (HAm4DH) in neutral ethanolic media led to the formation of complexes with the formulae [Cu(HAm4DH)X2] (X = Cl or Br) (1, 2) and [Cu(HAm4DH)2]X2 (X = NO3 or ClO4) (3, 4). The same reactions carried out in the presence of triethylamine gave rise to new complexes with the general formulae [Cu(Am4DH)X] (X = Cl, Br, AcO, or NO3) (5–8), [Cu(H2O)(Am4DH)](ClO4) (9), and [Cu(Am4DH)2] (10), many of which were isolated with different molecules of crystallization and contain a deprotonated thiosemicarbazone (Am4DH). These complexes were characterized by elemental analysis, and different spectroscopic and magnetic techniques. The thermal and redox behavior of the complexes was also evaluated. Complexes 1, 2, 5, and 6 show better nuclease activity than [Cu(phen)2]2+. Inaddition, crystals were isolated in the cases of [Cu(HAm4DH)Cl2]2 (5a), 1∞[Cu(Am4DH)Cl] (5b), 1∞[Cu(Am4DH)Br] (6a), and [Cu(HAm4DH)(H2O)(ClO4)2]·MeOH·H2O (9a) and these structures were analyzed by X‐ray diffraction. Compound 5a has a dimeric structure with chlorine bridges and shows weak antiferromagnetism (J = –12.2 cm–1). Complexes 5b and 6a are one‐dimensional polymers formed through halogen bridges and the deprotonated thiosemicarbazone in the thiolate form. In compound 9a the copper(II) is in a distorted octahedral environment with two ClO4 units coordinated to the metal center. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Supported Ionic Liquid Phase (SILP) Catalysis: An Innovative Concept for Homogeneous Catalysis in Continuous Fixed‐Bed Reactors
Authors: Riisager Anders , Fehrmann Rasmus , Haumann Marco , Wasserscheid Peter
Published: January 2006

Applications of ionic liquids to replace conventional solvents in homogeneous transition‐metal catalysis have increased significantly during the last decade. Biphasic ionic liquid/organic liquid systems offer advantages with regard to product separation, catalyst stability, and recycling but utilise in the case of fast chemical reactions only a small amount of expensive ionic liquid and catalyst. The novel Supported Ionic Liquid Phase (SILP) catalysis concept overcomes these drawbacks and allows the use of fixed‐bed reactors for continuous reactions. In this Microreview the SILP catalysis concept is surveyed by presenting results for the continuous gas‐phase hydroformylation of propene, as a reaction example. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Precursor‐Directed Biosynthesis of New Hormaomycin Analogues
Authors: Zlatopolskiy Boris D. , Radzom Markus , Zeeck Axel , de Meijere Armin
Published: January 2006

Several new analogues of hormaomycin (1), a peptide lactone with interesting biological activities, were prepared by total synthesis or by precursor‐directed biosynthesis. The new analogues 2a–c, 3a–c, O‐MOM‐1 and epi‐O‐MOM‐1 as well as the model acyl tripeptides 20a–c and 21a–e were tested for their antibiotic activities to give new insights into structure–activity relationships of this class of compounds. In this context, an unexpected activity of 2c against C. albicans was discovered. The precursors necessary for feeding experiments, the amino acids 14a, 14b and 17, were prepared in 31, 48 and 55 % yield over 4 and 3 steps, respectively. In addition, these studies provided some new information about the biosynthetic route to furnish compound 1. They also support the notion that the combination of chemical and biological methods may provide a broad range of analogues of an interesting biologically active natural product. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Chemoenzymatic One‐Pot Synthesis of Enantiopure L‐Arylalanines from Arylaldehydes
Authors: Paizs Csaba , Katona Adrian , Rétey János
Published: January 2006

Various enantiopure L‐arylalanines can be prepared from the corresponding arylaldehydes in one‐pot fashion by a combination of chemical and enzymatic reactions. The reagents used were (triphenyl‐λ5‐phosphanylidene)ethyl acetate (Wittig reaction), porcine liver esterase (PLE), phenylalanine ammonia lyase (PAL) from parsley and ammonia. As examples the following aryl groups were used: phenyl, 4‐chlorophenyl, 3‐fluorophenyl and thiophen‐2‐yl. The pure L‐enantiomers of phenyl‐, 4‐chlorophenyl‐, 3‐fluorophenyl‐ and thiophen‐2‐ylalanines were obtained after ion‐exchange chromatography in 88, 78, 72 and 91 % yields, respectively, calculated from the arylaldehydes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Enhanced binding and conformational selectivity in affinity capillary electrophoresis using a water‐soluble resorcin[4]arene as intrinsic buffer and electrokinetic host
Authors: Samson Sheeba , Britz‐McKibbin Philip
Published: January 2006

Affinity capillary electrophoresis (ACE) is a widely used technique for quantifying non‐covalent molecular interactions that is dependent on the specific buffer conditions selected. In this study, dynamic 1:1 host‐guest inclusion complexation involving a charged resorcin[4]arene with a group of neutral corticosteroids was examined by ACE, where the macrocycle serves as both an intrinsic buffer and electrokinetic host. It was determined that over a 200% enhancement in the apparent binding constant (KB) was realized by ACE when using the host as an intrinsic buffer at pH 7.5 relative to an extrinsic sodium phosphate buffer system, which was also confirmed by 1H‐NMR experiments. This report also revealed improved selectivity mediated by the discrete conformational properties of the complex among similar corticosteroid guests, as reflected by the complex mobility (μep, AC) or the relative change in complexation‐induced mobility (1–μep, AC/μep, C). This latter property is a unique feature of ACE reflective of hydrodynamic size selectivity involving bulky guests or substrates. 1H‐NMR and computer molecular modeling provided complementary information regarding the relative orientation, conformation and overall molecular area of the complex. The coupling of thermodynamic (KB) and electrokinetic (μep, AC) factors associated with complex formation in buffered solutions that minimize the effects of extrinsic electrolytes serves to enhance enthalpy‐driven molecular recognition processes by ACE.
Effects of G‐quartet DNA stationary phase destabilization on fibrinogen peptide resolution in capillary electrochromatography
Authors: Vo Trang U. , McGown Linda B.
Published: January 2006

The migration of fibrinogen peptides in capillaries coated with G‐quartet‐forming DNA oligonucleotides in open‐tubular CEC (OTCEC) was studied, in order to investigate factors affecting the retention of peptides on G‐quartet DNA stationary phases. At 25°C, the peptides eluted in the same order in OTCEC using a two‐plane G‐quartet DNA stationary phase as in CZE, including two peptides that were completely overlapped. It was found that baseline resolution of the coeluting peptides could be achieved in the OTCEC experiment, but not in CZE, at run temperatures of 35–40°C. A stationary phase formed by a scrambled‐sequence oligonucleotide that does not form a G‐quartet did not provide any resolution of the two coeluting peptides, even at the higher temperatures, indicating that some destabilization of the G‐quartet enhances resolution but that some degree of G‐quartet structure is necessary. The effects of destabilization were further explored through variation of the cations (sodium or potassium) used in attachment of the G‐quartet oligonucleotide to the capillary surface and in the mobile‐phase buffer. Resolution was lower when a more stable, four‐plane G‐quartet stationary phase was used, supporting the conclusion that some flexibility in the G‐quartet structure facilitates differential interactions that resolve otherwise coeluting peptides. The increase in peptide resolution upon destabilization of the G‐quartet structure could prove to be an important factor in the application of G‐quartet DNA stationary phases for nonaffinity‐based separation of native proteins and peptides.
Large‐pore mesoporous SBA‐15 silica particles with submicrometer size as stationary phases for high‐speed CEC separation
Authors: Tian Ruijun , Sun Junming , Zhang He , Ye Mingliang , Xie Chuanhui , Dong Jin , Hu Jiwei , Ma Ding , Bao Xinhe , Zou Hanfa
Published: January 2006

A new mesoporous sphere‐like SBA‐15 silica was synthesized and evaluated in terms of its suitability as stationary phases for CEC. The unique and attractive properties of the silica particle are its submicrometer particle size of 400 nm and highly ordered cylindrical mesopores with uniform pore size of 12 nm running along the same direction. The bare silica particles with submicrometer size have been successfully employed for the normal‐phase electrochromatographic separation of polar compounds with high efficiency (e.g., 210 000 for thiourea), which is matched well with its submicrometer particle size. The Van Deemeter plot showed the hindrance to mass transfer because of the existence of pore structure. The lowest plate height of 2.0 μm was obtained at the linear velocity of 1.1 mm/s. On the other hand, because of the relatively high linear velocity (e.g., 4.0 mm/s) can be generated, high‐speed separation of neutral compounds, anilines, and basic pharmaceuticals in CEC with C18‐modified SBA‐15 silica as stationary phases was achieved within 36, 60, and 34 s, respectively.
Recent advances in the applications of CE to forensic sciences (2001–2004)
Authors: Tagliaro Franco , Bortolotti Federica
Published: January 2006

The present article reviews the applications of CE in forensic science covering the period from 2001 until the first part of 2005. The overview includes the most relevant examples of analytical applications of capillary electrophoretic and electrokinetic techniques in the following fields: (i) Forensic drugs and poisons, (ii) explosive analysis and gunshot residues, (iii) small ions of forensic interest, (iv) forensic DNA and RNA analysis, (v) proteins of forensic interest, and (vi) ink analysis.
Genomewide screening of DNA copy number changes in chronic myelogenous leukemia with the use of high‐resolution array‐based comparative genomic hybridization
Authors: Hosoya Noriko , Sanada Masashi , Nannya Yasuhito , Nakazaki Kumi , Wang Lili , Hangaishi Akira , Kurokawa Mineo , Chiba Shigeru , Ogawa Seishi
Published: January 2006

Chronic myelogenous leukemia (CML) evolves from an indolent chronic phase (CP) characterized by the Philadelphia chromosome. Without effective therapy, it progresses to an accelerated phase (AP) and eventually to a fatal blast crisis (BC). To identify the genes involved in stage progression in CML, we performed a genomewide screening of DNA copy number changes in a total of 55 CML patients in different stages with the use of the high‐resolution array‐based comparative genomic hybridization (array CGH) technique. We constructed Human 1M arrays that contained 3,151 bacterial artificial chromosome (BAC) DNAs, allowing for an average resolution of 1.0 Mb across the entire genome. In addition to common chromosomal abnormalities, array CGH analysis unveiled a number of novel copy number changes. These alterations included losses in 2q26.2–q37.3, 5q23.1–q23.3, 5q31.2–q32, 7p21.3–p11.2, 7q31.1–q31.33, 8pter‐p12(p11.2), 9p, and 22q13.1–q13.31 and gains in 3q26.2–q29, 6p22.3, 7p15.2–p14.3, 8p12, 8p21.3, 8p23.2, 8q24.13–q24.21, 9q, 19p13.2–p12, and 22q13.1–q13.32 and occurred at a higher frequency in AP and BC. Minimal copy number changes affecting even a single BAC locus were also identified. Our data suggests that at least a proportion of CML patients carry still‐unknown cryptic genomic alterations that could affect a gene or genes of importance in the disease progression of CML. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045‐2257/suppmat. © 2006 Wiley‐Liss, Inc.
Hippocampal cell proliferation is reduced following prenatal ethanol exposure but can be rescued with voluntary exercise
Authors: Redila Van A. , Olson Andrea K. , Swann Sarah E. , Mohades Gisou , Webber Alina J. , Weinberg Joanne , Christie Brian R.
Published: January 2006

The ingestion of ethanol during pregnancy has a number of deleterious consequences for the unborn offspring, producing structural and functional deficits that affect the brain and many other organs into adulthood. The hippocampus is a brain area that is particularly sensitive to ethanol's adverse effects. In a previous study we showed that voluntary exercise can ameliorate deficits in long‐term potentiation and behavior that occur following prenatal ethanol exposure (Eur J Neurosci, 2005, 21, 1719–1726). In the present study, we investigated the effects of prenatal ethanol exposure on neurogenesis in adulthood, and tested the hypothesis that voluntary exercise would ameliorate any deficits observed. Sprague‐Dawley females were administered one of three diets throughout gestation: (i) ethanol (E), a liquid diet containing 36.5% ethanol‐derived calories; (ii) pair‐fed (PF), a liquid control diet, with maltose‐dextrin isocalorically substituted for ethanol, in the amount consumed by an E partner (g/kg body wt/day of gestation); and (iii) ad‐libitum‐fed control (C), normal laboratory chow and water, ad libitum. The offspring were housed individually at postnatal day (PND) 35, and at PND 50 were randomly assigned to cages either with or without an exercise wheel. BrdU (200 mg/kg, I.P.) was injected on PND 57, and animals terminated either 24 h (proliferation) or 4 weeks (neurogenesis) later. Our results demonstrate that prenatal ethanol exposure significantly decreases both cell proliferation and neurogenesis in the adult dentate gyrus. Animals in the PF condition also showed reduced neurogenesis. In contrast, all animals that engaged in voluntary exercise showed a significant increase in cell proliferation and neurogenesis. These results indicate that prenatal ethanol exposure can suppress both cell proliferation and neurogenesis, and that these effects may be, at least in part, nutritionally mediated. Importantly, voluntary exercise appears to have beneficial effects for these long‐lasting deficits in hippocampal volume and cell number that have been observed in animals exposed to ethanol in utero. © 2006 Wiley‐Liss, Inc.
Cancer incidence among pesticide applicators exposed to metolachlor in the Agricultural Health Study
Authors: Rusiecki Jennifer A. , Hou Lifang , Lee Won Jin , Blair Aaron , Dosemeci Mustafa , Lubin Jay H. , Bonner Matthew , Samanic Claudine , Hoppin Jane A. , Sandler Dale P. , Alavanja Michael C.R.
Published: January 2006

Metolachlor is one of the most widely used herbicides in the United States. We evaluated the incidence of cancer among pesticide applicators exposed to metolachlor in the Agricultural Health Study, a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina. A total of 50,193 pesticide applicators were included. Detailed information on pesticide exposure and lifestyle factors was obtained from self‐administered enrollment questionnaires completed between 1993 and 1997; average length of follow‐up was 7.33 years. Two metolachlor exposure metrics were used : (i) lifetime days personally mixed or applied metolachlor and (ii) intensity‐weighted lifetime days (lifetime days × an intensity level). Poisson regression analysis was used to estimate relative risks (RR) and 95% confidence intervals (95%CI) for cancer subtypes by tertiles of metolachlor exposure. No clear risk for any cancer subtype was found for exposure to metolachlor. A significantly decreased RR was found for prostate cancer in the highest category of lifetime days exposure (RR = 0.59; 95%CI, 0.39–0.89) and in the second highest category of intensity‐weighted lifetime days exposure (RR = 0.66; 95%CI, 0.45–0.97); however, the test for trend was not significant for either exposure metric. A nonsignificantly increased risk was found for lung cancer with lifetime days exposure in the highest category (RR = 2.37; 95%CI, 0.97–5.82, p‐trend = 0.03) but not with intensity‐weighted lifetime days. Given the widespread use of metolachlor and the frequent detection of metolachlor in both surface and ground water, future analyses of the AHS will allow further examination of long‐term health effects, including lung cancer and the less common cancers. © 2006 Wiley‐Liss, Inc.
Fruits and vegetables and renal cell carcinoma: Findings from the European prospective investigation into cancer and nutrition (EPIC)
Authors: Weikert Steffen , Boeing Heiner , Pischon Tobias , Olsen Anja , Tjonneland Anne , Overvad Kim , Becker Nikolaus , Linseisen Jacob , Lahmann Petra H. , Arvaniti Athina , Kassapa Christina , Trichoupoulou Antonia , Sieri Sabina , Palli Domenico , Tumino Rosario , Vineis Paolo , Panico Salvatore , van Gils Carla H. , Peeters Petra H. M. , Bueno‐de‐Mesquita H. Bas , Büchner Frederike L. , Ljungberg Börje , Hallmans Göran , Berglund Göran , Wirfält Elisabet , Pera Guillem , Dorronsoro Miren , Gurrea Aurelio Barricarte , Navarro Carmen , Martinez Carmen , Quirós J. Ramón , Allen Naomi , Roddam Andrew , Bingham Sheila , Jenab Mazda , Slimani Nadia , Norat Teresa , Riboli Elio
Published: January 2006

We examined the association between fruits and vegetables and risk of renal cell carcinoma (RCC) in the European Prospective Investigation into Cancer and Nutrition (EPIC). Dietary intake data and complete follow‐up information on cancer incidence were available for 375,851 participants recruited in EPIC centers of 8 countries. During an average follow‐up of 6.2 years, 306 incident cases of RCC were identified. The associations of consumption of total vegetables, total fruits, combined total fruits and vegetables and specific subtypes of vegetables with RCC risk were analyzed using Cox proportional hazards, stratified by centre and adjusted for potential confounders. No significant associations between fruit and vegetable consumption and RCC risk were observed despite a wide range of intake. The estimated relative risks (95% confidence intervals [CI]) in men and women combined were 0.97 (0.85–1.11) per 40 g increase in vegetable intake, 1.03 (0.97–1.08) per 40 g increase in fruit intake and 1.02 (0.93–1.11) per 80 g increase in fruit and vegetable intake combined. Among the vegetable subtypes, an inverse association was observed for root vegetables (RR per 8 g increase: 0.88; 95% CI: 0.78–0.99). These results suggest that total consumption of fruits and vegetables is not related to risk of RCC, although we cannot exclude the possibility that very low consumption is related to higher risk. The relationship of specific fruit and vegetable subgroups with RCC risk warrant further investigation. © 2006 Wiley‐Liss, Inc.
Iron and colorectal cancer risk in the α‐tocopherol, β‐carotene cancer prevention study
Authors: Cross Amanda J. , Gunter Marc J. , Wood Richard J. , Pietinen Pirjo , Taylor Philip R. , Virtamo Jarmo , Albanes Demetrius , Sinha Rashmi
Published: January 2006

In vitro and in vivo studies have associated iron with both the initiation and promotional stages of carcinogenesis. We investigated whether iron was associated with colorectal cancer in a nested case‐control study within the α‐tocopherol, β‐carotene cancer prevention study cohort. Exposure was assessed at baseline, using a 276‐item food frequency questionnaire and a fasting serum sample. The study included 130 colorectal cancer cases (73 colon cancers and 57 rectal cancers) and 260 controls. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Supplemental iron intake was only reported for 4 cases and 18 controls; therefore, we were unable to obtain meaningful results for this variable. Comparing the highest to the lowest quartiles, there was an inverse association between serum ferritin and colorectal cancer risk (OR = 0.4, 95% CI = 0.2–0.9) and a suggestion of an inverse association between dietary iron and colorectal cancer risk (OR = 0.4, 95% CI = 0.1–1.1). In addition, serum ferritin, serum iron and transferrin saturation were all inversely associated with colon cancer risk specifically (OR = 0.2, 95% CI = 0.1–0.7, p trend = 0.02; OR = 0.2, 95% CI = 0.1–0.9, p trend = 0.05; OR = 0.1, 95% CI = 0.02–0.5, p trend = 0.003, respectively), whereas serum unsaturated iron binding capacity was positively associated with colon cancer risk (OR = 4.7, 95% CI = 1.4–15.1, p trend = 0.009). In summary, we found a significant inverse association between several serum iron indices and colon cancer risk. © 2006 Wiley‐Liss, Inc.
Prognostic impact of hematogenous tumor cell dissemination in patients with stage II colorectal cancer
Authors: Koch Moritz , Kienle Peter , Kastrati Dorejd , Antolovic Dalibor , Schmidt Jan , Herfarth Christian , von Knebel Doeberitz Magnus , Weitz Jürgen
Published: January 2006

Adjuvant chemotherapy is not routinely recommended in patients with colorectal cancer stage UICC II. Some of these patients, however, develop recurrent disease. Therefore, valid prognostic criteria are needed to identify high‐risk patients who might benefit from adjuvant therapy. Disseminated tumor cells, detected in blood and bone marrow, may prove to be a valid marker, however, the prognostic relevance of these cells remains debated. In our study, we examined the prognostic significance of disseminated tumor cells in blood and bone marrow of patients with stage II colorectal cancer. Ninety patients with potentially curative (R0) resection of colorectal cancer stage II were prospectively enrolled into the study. Bone marrow and blood samples were examined for disseminated tumor cells by CK 20 RT‐PCR. Patient, tumor and treatment factors were analyzed as prognostic factors. Multivariate analysis confirmed tumor cell detection in blood (hazard ratio 2.1,p= 0.03) and T‐category (hazard ratio 2.2,p= 0.02) to be independent prognostic factors for relapse‐free survival. Tumor cell detection in postoperative blood samples (hazard ratio 7.7,p< 0.001) and number of removed lymph nodes (hazard ratio 6.4,p< 0.001) were independent prognostic factors for disease‐specific survival. Detection of circulating tumor cells in blood samples of patients with stage II colorectal cancer identifies patients with poor outcome. This finding should be confirmed by further studies and could then be used as a basis for conducting a randomized trial evaluating the effect of adjuvant chemotherapy in stage II patients. © 2006 Wiley‐Liss, Inc.
Air pollution and childhood cancer: A review of the epidemiological literature
Authors: Raaschou‐Nielsen Ole , Reynolds Peggy
Published: January 2006

The authors evaluated support in the literature for the hypothesis that ambient air pollution causes childhood cancer. The PubMed database was searched for original articles, which were reviewed for evidence of a relation with the main types of childhood cancer, using criteria including sample size, magnitude and precision of relative risk estimates, presence of a dose–response pattern and potential for bias. The hypothesis has been studied almost entirely with respect to traffic‐related air pollution. Since derivation of the hypothesis from 2 case–control studies in Denver, USA, two further case–control studies have provided new positive evidence and 4 case–control and 7 ecological studies mainly negative evidence. The 4 case–control studies providing positive evidence were relatively small and tended to have more methodological limitations than those showing no association. Publication bias is possible. The weight of the epidemiological evidence indicates no increased risk for childhood cancer associated with exposure to traffic‐related residential air pollution. Nevertheless, the limited number of studies, the methodological limitations of both positive and negative studies and the absence of consistency in the results obviate a firm conclusion of no effect. In particular, nondifferential misclassification of exposure might have masked true, weak associations. © 2006 Wiley‐Liss, Inc.
In vivo biostability of polysiloxane polyether polyurethanes: Resistance to metal ion oxidation
Authors: Ward Bob , Anderson James , Ebert Mike , McVenes Rick , Stokes Ken
Published: January 2006

Polyether polyurethanes are subject to oxidation catalyzed by and through direct (redox) reaction with transition metal ions (cobalt), released by corrosion of metallic parts in an implanted device. Replacing part of the polyether with polysiloxane appears to reduce susceptibility to metal ion oxidation (MIO). In vitro studies indicated that polyurethanes containing 20–35% polysiloxane (PS‐20 and PS‐35) are about optimum. We implanted tubing samples containing cobalt mandrels in the subcutis of rabbits for periods up to 2 years. After 2 years, only traces of microscopic cracks were seen on half the PS‐35 samples, PS‐20 significantly delayed MIO, while the polysiloxane‐free control was very severely degraded. Infrared spectroscopy established that polyether soft segment oxidation was occurring in PS‐20. We could not directly evaluate oxidation in PS‐35 because siloxane bands mask the aliphatic ether. Indirect FTIR evidence suggests that there is very slight polyether oxidation that develops early, and then seems to stabilize. The molecular weight of degraded PS‐20 decreased. That of microcracked PS‐35 decreased negligibly while that of undamaged PS‐35 increased slightly after 2‐year in vivo. The polysiloxane‐free control was profoundly degraded. PS‐20 has much improved MIO resistance, while that for PS‐35 is highly MIO resistant compared with its polysiloxane‐free control. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Biodegradable polymeric microspheres and nanospheres for drug delivery in the peritoneum
Authors: Kohane Daniel S. , Tse Julie Y. , Yeo Yoon , Padera Robert , Shubina Maria , Langer Robert
Published: January 2006

Drug delivery to the peritoneum is hampered by rapid clearance, and could be improved by application of controlled release technology. We investigated the suitability for peritoneal use of micro‐ and nanoparticles of poly(lactic‐co‐glycolic) acid (PLGA), a biodegradable polymer with generally excellent biocompatibility commonly used for controlled drug release. We injected 90 kDa PLGA microparticles, 5–250 μm in diameter, into the murine peritoneum, in dosages of 10–100 mg (n = 3–5 per group). We found a high incidence of polymeric residue and adhesions 2 weeks after injection (e.g., 50 mg of 5‐μm microparticles caused adhesions in 83% of animals). Histology revealed chronic inflammation, with foreign body giant cells prominent with particles >5 μm in diameter. Five micrometer microspheres made from 54, 57, and 10 kDa PLGA (gamma irradiated) caused fewer adhesions (16.7%) with a similar incidence of residue. Nanoparticles (265 nm) of 90 kDa PLGA also caused much fewer adhesions (6.3% of animals), possibly because they were cleared from the peritoneum within 2 days, and sequestered in the spleen and liver, where foamy macrophages were noted. The effect of sterilization technique on the incidence of adhesion formation is also studied. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Investigation of kinetics of iso‐octane ignition under scramjet conditions
Authors: Kahandawala Moshan S. P. , Corera Shehan A. P. , Williams Skip , Carter Campbell D. , Sidhu Sukh S.
Published: January 2006

A single pulse reflected shock tube was used to investigate iso‐octane ignition over the temperature range of 900–1400 K at a pressure of ∼1 atm. To account for the anticipated long ignition delay times at the lower temperatures, long shock tube dwell times (∼12 ms) at lower temperature and near atmospheric pressure were achieved by using argon–helium mix as a driver gas. Chemical thermometer experiments were conducted to remove any uncertainties in determining postreflected shock temperatures. The ignition delay data obtained in this study are in good agreement (in the overlap region) with the iso‐octane ignition data from a previous shock tube study. However, the activation energy of iso‐octane ignition obtained in this study in the lower temperature region (<1300 K) is significantly smaller (∼15 kcal vs. ∼40 kcal) than that obtained in a previous higher temperature study. The deflagration may be responsible for lowering of activation energy under the conditions of this study. Two detailed iso‐octane kinetic models (Air Force Research Laboratory—AFRL and Curran et al.) were used to model the experimental results of this study. The AFRL mechanism showed a good agreement with the experimental iso‐octane ignition delays and their temperature dependence. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 194–201, 2006
DFT Study of substituent effects of 2‐substituted alkyl ethyl methylcarbonates in homogeneous, unimolecular gas phase elimination kinetics
Authors: Añez Rafael , Herize Armando , Sierraalta Aníbal , Cordova Tania , Chuchani Gabriel
Published: January 2006

Theoretical studies on the gas phase elimination of 2‐substituted alkyl ethyl methylcarbonates were performed at the B3LYP/6‐31G* and B3LYP/6‐31+G** level of theory. The results of these calculations provide additional evidence that the mechanism of carbonates with a CβH bond proceeds through a concerted nonsynchronous six‐membered cyclic transition state to produce methylcarbonic acid and the corresponding olefin. The unstable intermediate, methylcarbonic acid, rapidly decomposes through a four‐membered cyclic transition state to methanol and carbon dioxide. The correlation of the logarithm of theoretical rate coefficients against Hancock's steric parameters E gave an approximate straight line (δ = 0.30, r = 0.996 at 400°C). An additional fact is that when experimental log kre.l is plotted against the theoretical log kre.l. for 2‐alkyl ethyl methylcarbonates an approximate straight line (r = 0.997 at 400°C) is obtained. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 184–193, 2006
Ammonium‐Functionalized Polydimethylsiloxanes: Synthesis and Properties
Authors: Novi Christina , Mourran Ahmed , Keul Helmut , Möller Martin
Published: January 2006

Summary: Polydimethylsiloxane with trimethylammonium end groups and polydimethylsiloxane with diethylmethylammonium groups in the main chain was prepared by two routes. A novel carbonate coupler – (2‐oxo‐1,3‐dioxolan‐4‐yl) methyl phenyl carbonate – and the amine compounds α,ω‐(3‐aminopropyl) polydimethylsiloxane, 3‐(dimethylamino)‐1‐propylamine, and bis(2‐amino ethyl)amine served as the starting materials. The polymers obtained are hydrophobic and contain ammonium groups suitable for interaction with negatively charged surfaces. Thus these materials can be used for special surface modifications. Thin films were prepared by spin‐coating. Their morphology and properties were determined by means of optical microscopy, SFM, and contact angle measurements. The particle size distribution in aqueous solution of the vesicles formed was determined by means of a laser scattering technique; the particle sizes determined correspond to those obtained by optical microscopy. Finally, the antibacterial effects of these polymers with hydrophobic and cationic groups were tested.

α,ω‐Diammonium octadimethylsiloxane molecule (6), an SFM phase image for a spin‐coated film of 6 on a silicon wafer, and a scheme of the way the molecules stack on the surface.

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α,ω‐Diammonium octadimethylsiloxane molecule (6), an SFM phase image for a spin‐coated film of 6 on a silicon wafer, and a scheme of the way the molecules stack on the surface.
Activation of rac‐Me2Si(ind)2ZrCl2 by Methylalumoxane Modified by Aluminum Alkyls: An EPR Spin‐Probe, 1H NMR, and Polymerization Study
Authors: Bryliakov Konstantin P. , Semikolenova Nina V. , Panchenko Valentina N. , Zakharov Vladimir A. , Brintzinger Hans H. , Talsi Evgenii P.
Published: January 2006

Summary: Solutions containing mixtures of methylalumoxane (MAO) and iBu3Al give rise to 1H NMR signals indicative of the presence of the mixed alkyl aluminum dimers iBu2Al(µ‐Me)2AliBu2 and of mixed clusters of the type (AlMe(1 + 2x − y)iBuyO(1 − x))n. These mixed clusters, as well as related species present in solutions containing either MAO–Et3Al or commercially available modified MAO (MMAO), appear to have stronger Lewis acidic sites and greater hydrodynamic radii than comparable clusters present in solutions of MAO alone, as judged from EPR signals observed in these solutions upon addition of TEMPO. When (SBI)ZrCl2 (SBI = rac‐Me2Si(ind)2) is reacted with one of these mixed activator reagents, the mixed heterobinuclear cation [(SBI)Zr(µ‐Me)2AlMeiBu]+ appears to be formed, together with its methyl counterpart [(SBI)Zr(µ‐Me)2AlMe2]+, which is normally predominant in the (SBI)ZrCl2/MAO system at [Al]MAO/[Zr] ratios above 100. In the presence of iBu3Al, the formation of heterobinuclear cations is suppressed in favor of ion pairs containing the cation [(SBI)ZrMe]+ in contact with a (MAO–TIBA)‐derived counter anion. The greater reactivity of these contact‐ion pairs, as compared to the normally prevalent AlMe3 adducts, as well as an increased Lewis acidity of MMAO, and the ensuing decreased coordination ability of the [Me‐(MAO–TIBA)]− counter ion as compared to [Me‐MAO]−, are likely to contribute to the positive effects of TIBA additions on the co‐catalytic activity of MAO.

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Efficient Donor for Terbium Luminescence Based on Polymer Ligand Containing Quinolinone Fluorophore
Authors: Výprachtický Drahomír , Cimrová Věra , Kukla Stanislav , Pavlačková Petra
Published: January 2006

Summary: Polymer ligand containing a quinolinone fluorophore and carboxyl binding sites (III) was synthesized by the reaction of parent poly[styrene‐alt‐(maleic anhydride)] with 7‐amino‐4‐methylquinolin‐2(1H)‐one (I) and methanol. The ligand‐to‐metal resonance energy transfer and ligand binding properties of Tb(III)‐III complexes were investigated by steady‐state and time‐resolved luminescence spectroscopy in methanol or deuterated methanol and compared with those of the low‐molecular‐weight model compound, N‐[4‐methyl‐2‐oxo‐1,2‐dihydroquinolin‐7‐yl]succinamic acid (II). The long‐lived emission intensity of Tb3+ at 490, 545, 585, and 620 nm corresponding to the 5D4 → 7F6, 5D4 → 7F5, 5D4 → 7F4, and 5D4 → 7F3 transitions, respectively, was strongly increased by the addition of III (as much as 10 000 times) and decreased in the order of Tb(III)‐III ≫ Tb(III)‐II > Tb(III)‐I > Tb(III). The efficiency of energy transfer (E) was evaluated from emission intensity of the donor (III) in the presence or absence of the acceptor (Tb3+) as E = 0.71–0.94, depending on the acceptor concentration and ligand neutralization. The experimental luminescence‐decay curves were double‐exponential (τ1, τ2) with a predominating longer component (rel B1 = 85%) for Tb(III)‐III and single‐exponential (τ) for Tb(III)‐II. One or three methanol molecules were coordinated to Tb3+ in Tb(III)‐III with or without neutralization of III, respectively, whereas approximately 6.5 methanol molecules were coordinated to Tb3+ in Tb(III)‐II. Terbium ion coordinates with 7–8 molecules of methanol in methanolic solution.

Schematic energy‐level diagram for fluorescence resonance energy transfer in a Tb(III)‐ligand complex.

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Schematic energy‐level diagram for fluorescence resonance energy transfer in a Tb(III)‐ligand complex.
Effect of β‐Cyclodextrins on the Morphological Change of Poly(3‐hydroxybutyrate)
Authors: Shin Kyung‐moo , Dong Tungalag , He Yong , Inoue Yoshio
Published: January 2006

Summary: The effects of β‐CD, partially methylated and per‐methylated β‐CDs on the crystallization behavior of P(3HB) have been investigated. All measurements, including FT‐IR spectra, WAXD, and DSC, showed that the details of interaction between P(3HB) and respective CDs were varied with the degree of methyl substitution of CDs. The crystallization of P(3HB) was enhanced by an addition of immiscible β‐CD, while it was restricted by the introduction of methylated CDs via the formation of miscible blend with di‐O‐methyl β‐CD and via the formation of an IC with tri‐O‐methyl β‐CD, respectively.

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Cover Picture: Macromol. Theory Simul. 1/2006
Authors: Zetterlund Per B. , Okubo Masayoshi
Published: January 2006

Cover: The influence on polymerization kinetics of the Laplace pressure in polymer particles in heterogeneous radical polymerization is investigated. The Figure on the cover shows (kp/kt0.5)/(kp/kt0.5)0 (subscript 0 denotes atmospheric pressure) vs. particle radius for styrene at 60 °C at low conversion (black line) and 50% conversion (red line) with γ(styrene) = 30 mN · m−1. Further details can be found in the article by P. B. Zetterlund and M. Okubo* on page 40.
Beneficial effects of tea and its polyphenols against prostate cancer
Authors: Siddiqui Imtiaz A. , Adhami Vaqar M. , Saleem Mohammad , Mukhtar Hasan
Published: January 2006

Tea, next to water, is the most widely consumed beverage in the world. Depending upon the level of fermentation, tea can be categorized into three types: green (unfermented), oolong (partially fermented), and black (highly to fully fermented). In general, green tea has been found to be superior to black and oolong tea in terms of antioxidant and health promoting benefits owing to the higher content of (–)‐epigallocatechin‐3‐gallate. Tea polyphenols comprise about one‐third of the weight of the dried leaf, and they exhibit biochemical and pharmacological activities including antioxidant activities, inhibition of cell proliferation, induction of apoptosis, cell cycle arrest and modulation of carcinogen metabolism. Several studies demonstrate that most tea polyphenols exert their effects by scavenging reactive oxygen species (ROS) since excessive production of ROS has been implicated in the development of a variety of ailments including cancer of the prostate gland (CaP). Using cell culture and animal model systems, molecular targets for these remarkable beneficial effects of green tea drinking on CaP prevention and therapy have been defined. Geographical and case‐control studies are showing that green tea drinking could afford CaP chemopreventive effects in human population. In this review we attempt to summarize the experimental as well as the epidemiological basis for the possible role of tea and its polyphenols for chemoprevention and chemotherapy of CaP.
Comments on ‘Piperidone derivative from Dalbergia sympathetica’
Authors: Winkler Tammo
Published: January 2006

Alcoholic extraction of Dalbergia sympathetica leaves yielded N‐methyl‐trans‐4‐hydroxy‐L‐proline and not 3,6‐dihydroxy‐N‐methyl‐2‐piperidone, as previously reported. This is shown by the identity of the 1H and 13C NMR data of the isolated compound with those of N‐methyl‐trans‐4‐hydroxy‐L‐proline. Copyright © 2006 John Wiley & Sons, Ltd.
Role of the basic helix‐loop‐helix protein ITF2 in the hormonal regulation of Sertoli cell differentiation
Authors: Muir Terla , Sadler‐Riggleman Ingrid , Stevens Jeffrey D. , Skinner Michael K.
Published: January 2006

Sertoli cells are a post‐mitotic terminally differentiated cell population that forms the seminiferous tubules in the adult testis and provides the microenvironment and structural support for developing germ cells. During pubertal development, Sertoli cells are responsive to follicle‐stimulating hormone (FSH) to promote the expression of differentiated gene products. The basic helix‐loop‐helix (bHLH) and inhibitors of differentiation (Id) transcription factors are involved in the differentiation of a variety of cell lineages during development. Both bHLH and Id transcription factors have been identified in Sertoli cells. A yeast two‐hybrid screen was conducted using a rat Sertoli cell cDNA library to identify bHLH dimerization partners for the Id1 transcription factor. The ubiquitous bHLH protein ITF2 (i.e., E2‐2) was identified as one of the interacting partners. The current study investigates the expression and function of ITF2 in Sertoli cells. ITF2 was found to be ubiquitously expressed in all testicular cell types including germ cells, peritubular myoid cells, and Sertoli cells. Stimulation of cultured Sertoli cells with FSH or dibutryl cAMP resulted in a transient decrease in expression of ITF2 mRNA levels followed by a rise in expression with FSH treatment. ITF2 expression was at its highest in mid‐pubertal 20‐day‐old rat Sertoli cells. ITF2 was found to directly bind to negative acting Id HLH proteins and positive acting bHLH proteins such as scleraxis. Transient overexpression of ITF2 protein in cultured Sertoli cells stimulated transferrin promoter activity, which is a marker of Sertoli cell differentiation. Co‐transfections of ITF2 and Id proteins sequestered the inhibitory effects of the Id family of proteins. Observations suggest ITF2 can enhance FSH actions through suppressing the inhibitory actions of the Id family of proteins and increasing the actions of stimulatory bHLH proteins (i.e., scleraxis) in Sertoli cells. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Establishment of an in vitro culture system for chicken preblastodermal cells
Authors: Park Hyun Jeong , Park Tae Sub , Kim Tae Min , Kim Jin Nam , Shin Sang Su , Lim Jeong Mook , Han Jae Yong
Published: January 2006

To develop an alternative source for chicken pluripotent cells, we examined (1) whether undifferentiated preblastodermal cells could be subcultured in vitro for an extended period and (2) how subculturing affected the physiological properties of preblastodermal cells. The average number of preblastodermal cells was 2,397 in stage V embryos and 36,345 in stage VII embryos; stage X embryos had an average of 53,857 blastodermal cells. The average cell size decreased significantly (70.63–18.83 µm in diameter; P < 0.0001) as the embryo grew; this was closely related to a reduction in the size and number of lipid vesicles in the cell cytoplasm. The culture conditions were optimized for the stage V preblastodermal cells and the control stage X blastodermal cells. On STO feeder cells, the preblastodermal cells achieved stable growth in vitro only in HES medium or a mixed medium of the Knockout DMEM and HES media. However, more than 10 passages of preblastodermal cells at intervals of 3–4 days was possible only by using the Knockout/HES mixed medium and BRL cell‐conditioned HES medium for the primary cultures and subcultures, respectively. Colony‐forming preblastodermal cells had well‐delineated cytoplasm, which was positively stained for stem cell‐specific markers by anti‐stage‐specific embryo antigen‐1 antibody, periodic acid‐Schiff's solution, and alkaline phosphatase. When preblastodermal cells with or without culturing were transferred into the blastodermal cavity of stage X embryos, only in vitro‐cultured preblastodermal cells at stage V (4/5 = 80%) and stage VII (2/8 = 25%) induced somatic chimerism in recipient chickens. In conclusion, undifferentiated preblastodermal cells could be subcultured, and only the colony‐forming preblastodermal cells that stained positively for stem cell markers could induce somatic chimerism. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.
Fatal Fournier's gangrene in a young adult with acute lymphoblastic leukemia
Authors: Mantadakis Elpis , Pontikoglou Charalampos , Papadaki Helen A. , Aggelidakis George , Samonis George
Published: January 2006

Fournier's gangrene (FG) is a fulminant necrotizing fasciitis of the external genitalia. Few reports of FG exist in patients with hematologic malignancies. We describe a case of fatal FG in a 21‐year‐old man with acute lymphoblastic leukemia who was receiving remission‐induction chemotherapy. Despite early local surgery, administration of appropriate antibiotics, resurgery for wider debridement and aggressive ICU support he succumbed while pancytopenic to septic shock, 26 days after initiation of chemotherapy. Multi‐drug resistant Pseudomonas aeruginosa was isolated from blood and scrotal cultures obtained at initial surgery. FG is a fulminant infection, especially in the face of profound cytopenias. Pediatr Blood Cancer 2007;49:862–864. © 2006 Wiley‐Liss, Inc.
Runx2 phosphorylation induced by fibroblast growth factor‐2/protein kinase C pathways
Authors: Kim Byung‐Gyu , Kim Hyun‐Jung , Park Hye‐Jeong , Kim Youn‐Jeong , Yoon Won‐Joon , Lee Seung‐Jin , Ryoo Hyun‐Mo , Cho Je‐Yoel
Published: January 2006

Runx2 is a key transcription factor in osteoblast differentiation, and its activity is regulated by fibroblast growth factors (FGFs). Craniosynostosis, characterized by premature suture closure, results from mutations that generate constitutively active FGF receptors (FGFRs). We previously showed that FGF/FGFR‐activated protein kinase C (PKC) is involved in the expression and activity of Runx2. Activated PKCδ physically interacts with Runx2 in FGF2‐stimulated MC3T3‐E1 preosteoblastic cells. Immunopurified Runx2 protein reacted with PKCδ kinase, and a phosphorylated 1460‐Da peptide fragment (amino acids 241–252, 1380‐Da) derived from Runx2 was also detected in MS analysis. Computer analysis predicted that Ser247 in this Runx2 can be a possible phosphorylation site by PKCδ. We also showed that Runx2 activity after FGF stimulation correlates with the presence of the Runx2 Ser247 residue. The S247A (Ser → Ala) mutation confers decreased transcriptional activity on a Runx2‐responsive promoter after FGF treatment.
Proteomic analysis of pathogenic bacterium Vibrio vulnificus
Authors: Lee Ah Young , Park Sung Goo , Jang Mi , Cho Sayeon , Myung Pyung Keun , Kim Young Ran , Rhee Joon Haeng , Lee Do Hee , Park Byoung Chul
Published: January 2006

In this study we have constructed a proteome reference map of the pathogenic bacterium Vibrio vulnificus. From the reference map, we identified several virulence‐related proteins, such as ToxR and ToxS, as well as numerous proteins involved in diverse cellular functions. To search for additional virulence‐related proteins, we compared the whole proteomes from the wild‐type and toxR mutant of V. vulnificus and found that several proteins were up‐ or down‐regulated in the toxR mutant. We suggest that these differentially regulated proteins whose expression is coordinately controlled by a virulence regulator ToxR, some of which are already implicated in virulence, play roles in the pathogenesis of V. vulnificus.
The cassava (Manihot esculenta Crantz) root proteome: Protein identification and differential expression
Authors: Sheffield Jeanne , Taylor Nigel , Fauquet Claude , Chen Sixue
Published: January 2006

Using high‐resolution 2‐DE, we resolved proteins extracted from fibrous and tuberous root tissues of 3‐month‐old cassava plants. Gel image analysis revealed an average of 1467 electrophoretically resolved spots on the fibrous gels and 1595 spots on the tuberous gels in pH 3–10 range. Protein spots from both sets of gels were digested with trypsin. The digests were subjected to nanoelectrospray quadrupole TOF tandem mass analysis. Currently, we have obtained 299 protein identifications for 292 gel spots corresponding to 237 proteins. The proteins span various functional categories from energy, primary and secondary metabolism, disease and defense, destination and storage, transport, signal transduction, protein synthesis, cell structure, and transcription to cell growth and division. Gel image analysis has shown unique, as well as up‐ and down‐regulated proteins, present in the tuberous and the fibrous tissues. Quantitative and qualitative analysis of the cassava root proteome is an important step towards further characterization of differentially expressed proteins and the elucidation of the mechanisms underlying the development and biological functions of the two types of roots.