bluuebunny/crossref_metadata_2025 huggingface dataset:
Probing bacterial nucleoid structure with optical tweezers
Authors: Dorman Charles J.
Published: February 2007

The H‐NS protein is a major component of the nucleoid in Gram‐negative bacterial cells. It is a global regulator of transcription that affects the expression of many genes, including virulence genes in pathogenic species. At a local level, it facilitates the formation of nucleoprotein structures that repress transcriptional promoter function. H‐NS can form bridges between different DNA molecules or between different sections of the same molecule, allowing it to compact and impose structure on the nucleoid. A recent paper by Dame et al.1 reports new insights into H‐NS‐mediated DNA bridging that were obtained using an optical tweezers device. BioEssays 29: 212–216, 2007. © 2007 Wiley Periodicals, Inc.
Stalk‐eyed flies (Diopsidae): Modelling the evolution and development of an exaggerated sexual trait
Authors: Warren Ian , Smith Hazel
Published: February 2007

Stalk‐eyed flies of the family Diopsidae exhibit a unique form of hypercephaly, which has evolved under both natural and sexual selection. Male hypercephaly is used by female diopsids as an indicator of male quality. By choosing to mate with males expressing the most‐exaggerated hypercephaly, females can benefit both from the enhanced fertility of these males and the transmission of other heritable advantages to their offspring. Stalk‐eyed flies are close relatives of the model organism, Drosophila melanogaster. We have shown that similar genetic and cellular mechanisms regulate the initial development of the head capsule in fruitflies and diopsids. The great diversity of stalk‐eyed fly species, exhibiting varying degrees of hypercephaly and sexual dimorphism, constitutes a major advantage for comparative studies of their development and evolution. BioEssays 29: 300–307, 2007. © 2007 Wiley Periodicals, Inc.
The relationship between non‐protein‐coding DNA and eukaryotic complexity
Authors: Taft Ryan J. , Pheasant Michael , Mattick John S.
Published: February 2007

There are two intriguing paradoxes in molecular biology—the inconsistent relationship between organismal complexity and (1) cellular DNA content and (2) the number of protein‐coding genes—referred to as the C‐value and G‐value paradoxes, respectively. The C‐value paradox may be largely explained by varying ploidy. The G‐value paradox is more problematic, as the extent of protein coding sequence remains relatively static over a wide range of developmental complexity. We show by analysis of sequenced genomes that the relative amount of non‐protein‐coding sequence increases consistently with complexity. We also show that the distribution of introns in complex organisms is non‐random. Genes composed of large amounts of intronic sequence are significantly overrepresented amongst genes that are highly expressed in the nervous system, and amongst genes downregulated in embryonic stem cells and cancers. We suggest that the informational paradox in complex organisms may be explained by the expansion of cis‐acting regulatory elements and genes specifying trans‐acting non‐protein‐coding RNAs. BioEssays 29: 288–299, 2007. © 2007 Wiley Periodicals, Inc.
The origins of polypeptide domains
Authors: Schmidt Edward E. , Davies Christopher J.
Published: February 2007

Three decades ago Gilbert posited that novel proteins arise by re‐shuffling genomic sequences encoding polypeptide domains. Today, with numerous genomes and countless genes sequenced, it is well established that recombination of sequences encoding polypeptide domains plays a major role in protein evolution. There is, however, less evidence to suggest how the novel polypeptide domains, themselves, arise. Recent comparisons of genomes from closely related species have revealed numerous species‐specific exons, supporting models of domain origin based on “exonization” of intron sequences. Also, a mechanism for the origin of novel polypeptide domains has been proposed based on analyses of insertion‐based polymorphisms between orthologous genes across broad phylogenetic spectra and between allelic variants of genes within species. This review discusses these processes and how each might participate in the evolutionary emergence of novel polypeptide domains. BioEssays 29: 262–270, 2007. © 2007 Wiley Periodicals, Inc.
DNA methylation with a sting: An active DNA methylation system in the honeybee
Authors: Schaefer Matthias , Lyko Frank
Published: February 2007

The existence of DNA methylation in insects has been a controversial subject over a long period of time. The recently completed genome sequence of the honeybee Apis mellifera has revealed the first insect with a full complement of DNA methyltransferases.1 A parallel study demonstrated that these enzymes are catalytically active and that Apis genes can be methylated in specific patterns.2 These findings establish bees as a model to analyze the function of DNA methylation systems in invertebrate organisms and might also be important to understand evolutionary aspects of DNA methylation in higher eukaryotes. BioEssays 29: 208–211, 2007. © 2007 Wiley Periodicals, Inc.
Stereospecific determination of cis‐ and trans‐resveratrol in rat plasma by HPLC: application to pharmacokinetic studies
Authors: Chen Xijing , He Hui , Wang Guangji , Yang Bing , Ren Weichao , Ma Le , Yu Qiaoling
Published: February 2007

A simple, accurate, precise, specific and reproducible high‐performance liquid chromatography (HPLC) method was developed for simultaneous determination of resveratrol isomers in rat plasma. Cis‐resveratrol was made by exposure of a trans‐resveratrol solution to sunlight for 5 days followed by separation by HPLC and identification by mass spectrometry (MS). The assay procedure involved simple liquid–liquid extraction of resveratrol isomers and internal standard (IS, caffeine) from a small plasma volume directly into acetonitrile. The supernatant liquid was added an equal volume of water and injected onto a Hypersil ODS2 C18 column (5 µm, 4.6 × 250 mm). Mobile phase consisting of methanol and distilled water was used at a flow rate of 1.0 mL/min for the effective separation of cis‐, trans‐resveratrol and caffeine (IS). The detection of the analyte peak was achieved by monitoring the eluate using a UV detector set at 303 nm. The ratio of peak area of analyte to IS was used for quantification of plasma samples. Nominal retention times of cis‐, trans‐resveratrol and IS were 3.2, 4.3 and 6.1 min, respectively. The calibration curve was linear ranging from 0.066 to 6.64 and 0.134 to 13.4 µg/mL with correlation coefficients of 0.9998 and 0.9997 for trans and cis isomers, respectively. The absolute recovery of both isomers was more than 85%. The inter‐ and intra‐day precisions in the measurement of quality control (QC) samples, 0.066, 0.664 and 6.64 µg/mL of trans‐resveratrol, were in the range 2.37–6.95% relative standard deviation (RSD) and 0.77–6.97% RSD, respectively. The inter‐ and intra‐day precisions in the measurement of quality control (QC) samples, 0.134, 1.34 and 13.4 µg/mL of cis‐resveratrol, were in the range 1.93–3.72% relative standard deviation (RSD) and 1.13–6.57% RSD, respectively. Both analytes and IS were stable in the battery of stability studies and freeze–thaw cycles. Resveratrol isomers were found to be stable for a period of 30 days on storage at −20°C. The application of the assay to determine the pharmacokinetic disposition after a single oral dose to rats is described. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of anabolic steroids in hair by GC/MS/MS
Authors: Gambelunghe C. , Sommavilla M. , Ferranti C. , Rossi R. , Aroni K. , Manes N. , Bacci M.
Published: February 2007

ASTRACT: A simple and sensitive gas chromatography/tandem mass spectrometry (GC/MS/MS) method is described for the detection of anabolic steroids, usually found in keratin matrix at very low concentrations. Hair samples from seven athletes who spontaneously reported their abuse of anabolic steroids, and in a single case cocaine, were analyzed for methyltestosterone, nandrolone, boldenone, fluoxymesterolone, cocaine and its metabolite benzoylecgonine. Anabolic steroids were determinate by digestion of hair samples in 1 m NaOH for 15 min at 95°C. After cooling, samples were purificated by solid‐phase and liquid–liquid extraction, then anabolic steroids were converted to their trimethylsilyl derivative and finally analyzed by GC/MS/MS. For detection of cocaine and benzoylecgonine, hair samples were extracted with methanol in an ultrasonic bath for 2 h at 56°C then overnight in a thermostatic bath at the same temperature. After the incubation, methanol was evaporated to dryness, and benzoylecgonine was converted to its trimethylsilyl derivative prior of GC/MS/MS analysis. Results obtained are in agreement with the athletes' reports, confirming that hair is a valid biological matrix to establish long‐term intake of drugs. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitative LC/MS/MS method and in vivo pharmacokinetic studies of vitexin rhamnoside, a bioactive constituent on cardiovascular system from hawthorn
Authors: Liang Mingjin , Xu Wen , Zhang Weidong , Zhang Chuan , Liu Runhui , Shen Yunheng , Li Huiliang , Wang Xiaolin , Wang Xiangwei , Pan Qiongqun , Chen Chunlin
Published: February 2007

A simple and accurate liquid chromatography coupled with tandem mass spectrometry method was developed for determination and in vivo pharmacokinetic studies of vitexin rhamnoside in rat plasma. After protein precipitation using methanol, the analytes were separated by a Luna C18 column with an isocratic elution and analyzed by mass spectrometry in multiple reaction monitoring mode using the respective negative ion at m/z 577.2–293.0 for vitexin rhamnoside and m/z 593.2–413.0 for internal standard (IS) vitexin glucoside. The method was validated systematically within the concentration range 5–5000 µg/L (R > 0.996) and the lower limit of quantitation was 5 µg/L. Acceptable precision and accuracy were acquired for concentrations over the standard curve range. It was further applied to assess pharmacokinetics and bioavailability of vitexin rhamnoside after intravenous and oral administration to rats. The oral bioavailability of vitexin rhamnoside was only 3.57%, which indicated that vitexin rhamnoside had poor absorption or underwent extensive first‐pass metabolism. Practical utility of this new LC/MS/MS method was confirmed in pilot pharmacokinetic studies in rats following both intravenous and oral administration. Copyright © 2007 John Wiley & Sons, Ltd.
Comparative study on the interaction of recombinant human soluble catechol‐O‐methyltransferase on some hydrophobic adsorbents
Authors: Passarinha L. A. , Bonifácio M. J. , Queiroz J. A.
Published: February 2007

The main scope of this work is the evaluation and potential application of hydrophobic interaction chromatography in the isolation of recombinant human soluble catechol‐O‐methyltransferase (hSCOMT) from an Escherichia coli cell extract. Therefore, a comparative study on the interaction of recombinant hSCOMT with different hydrophobic adsorbents (butyl‐, octyl‐, phenyl‐ and epoxy‐Sepharose), was developed. The four adsorbents were evaluated in terms of selectivity, recovery and fractionation of recombinant hSCOMT from its Escherichia coli‐free culture broth. Our data shows that the adjustment of the ionic strength on the mobile phase and the type of hydrophobic ligand are the most useful factors for a complete binding of hSCOMT and a selective fractionation of contaminating proteins. The results of these studies demonstrate that, although epoxy‐Sepharose is used as a last resort due to the high salt concentrations needed, hSCOMT bind to the other three resins at low concentrations of ammonium sulfate (≤0.6 m) and eluted just by decreasing the ionic strength on the eluent to 0 m, without loss of specific of activity. The stepwise gradient with 0.6, 0.2, 0.075 and 0 m of ammonium sulfate onto a butyl‐Sepharose media was found to be the most effective in the isolation of hSCOMT, leading to an enzyme solution with a 3.9‐fold increased in specific activity. Since biochemical and structural studies require significant quantities of the enzyme in an active form, the above described approach may give some insight into the optimization and development of new purification strategies of mammalian COMTs. Copyright © 2007 John Wiley & Sons, Ltd.
Permeability of atenolol and propranolol in the presence of dimethyl sulfoxide in rat single‐pass intestinal perfusion assay with liquid chromatography/UV detection
Authors: Venkatesh Gantala , Ramanathan S. , Nair N. K. , Mansor S. M. , Sattar Munavvar Abdul , Khan Md. Abdul Hye , Navaratnam V.
Published: February 2007

A simple and sensitive RP‐HPLC‐UV method was developed and validated for simultaneous determination of atenolol and propranolol and subsequently applied to investigate the effect of dimethyl sulfoxide in rat in situ intestinal permeability studies. Atenolol (400 µm) and propranolol (100 µm) were perfused in the small intestine of anaesthetized (pentobarbitone sodium 60 mg/kg, i.p.) male Sprague–Dawley rats either in the presence (1, 3 and 5%) or in the absence of dimethyl sulfoxide. There was no significant alteration (p > 0.05) in the permeability of atenolol and propranolol, which indicated there was no effect of various concentrations of dimethyl sulfoxide (1–5%) on the membrane integrity of the rat intestinal tissues. The analytical method was validated on a C4 column with a mobile phase comprising ammonium acetate buffer (pH 3.5, 0.02 m) and acetonitrile in the ratio of 30:70 (v/v) at a flow rate of 1.0 mL/min. The validated method was found to be accurate and precise and stability studies were carried out at different storage conditions and both analytes were found to be stable. These findings are applicable for determining the absorbability of water‐insoluble drugs and new chemical entities for the purpose of classifying them in the biopharmaceutical classification system. Copyright © 2007 John Wiley & Sons, Ltd.
Rapid determination of cinchocaine in skin by high‐performance liquid chromatography
Authors: Elsayed Mustafa M. A.
Published: February 2007

A simple, rapid, accurate, precise and specific analytical method has been developed, validated and applied for determination of cinchocaine in guinea pig and albino rabbit dorsal skins, after in vivo application of cinchocaine formulations. Extraction was performed using a solvent mixture of ethanol and 0.1 M hydrochloric acid (90:10; v/v). Samples were chromatographed on Spheri‐5, RP18 column with a particle size of 5 µm and 220 mm × 4.6 mm i.d. The mobile phase was a mixture of acetonitrile and triethylamine phosphate buffer (pH 2.8; 0.04 M) (60:40, v/v). UV detection was carried out at 247 nm and the run time was 6 min with typical retention time of cinchocaine of 3.63 ± 0.02 min. Specificity was demonstrated, showing that the cinchocaine peak was free of interference from skin endogenous components. The detector response was found to be linear in the concentration range 0.96–56.00 µg/mL with a coefficient of correlation r = 0.99996. The relative standard deviations of within‐ and between‐day analyses were all below 5%. The drug extraction procedure was validated. Satisfactory recoveries with relative standard deviation values below 5% were obtained, indicating efficient quantitative reproducible extraction procedure. Copyright © 2007 John Wiley & Sons, Ltd.
Simultaneous quantification of five anthraquinones in rat plasma by high‐performance liquid chromatography with fluorescence detection
Authors: Yan Dongming , Ma Yueming
Published: February 2007

A sensitive high‐performance liquid chromatographic method with fluorescence detection (excitation 435 and emission 515 nm) was established and validated for quantification of five anthraquinones (aloe‐emodin, rhein, emodin, chrysophanol and physcion) in rat plasma. Following a single‐step liquid–liquid extraction, the analytes and internal standard (1,8‐dihydroxyanthraquinone) were separated on a reversed‐phase C18 column with water–phosphoric acid–methanol as mobile phase at a flow rate of 1 mL/min. The linear ranges of the calibration curves were 6.5–1300 ng/mL for aloe‐emodin, 20–4000 ng/mL for rhein, 40–8000 ng/mL for emodin, 15–3000 ng/mL for chrysophanol and 13–2600 ng/mL for physcion. The lower limit of quantification was 6.5 ng/mL for aloe‐emodin, 20 ng/mL for rhein, 40 ng/mL for emodin, 15 ng/mL for chrysophanol and 13 ng/mL for physcion. The mean accuracy was 94.3–105.1% for aloe‐emodin, 90.3–108.8% for rhein, 92.6–106.7% for emodin, 95.8–103.8% for chrysophanol and 98.7–101.2% for physcion. The within‐batch and between‐batch precisions were ≤5.5% and ≤13.4%, respectively. This method is suitable for determining the five anthraquinones in plasma simultaneously and thus investigating the pharmacokinetics of anthraquinones from Xiexin decoction in rats. Copyright © 2007 John Wiley & Sons, Ltd.
Simultaneous determination of aminothiols, ascorbic acid and uric acid in biological samples by capillary electrophoresis with electrochemical detection
Authors: Yao Xiao , Wang Yuting , Chen Gang
Published: February 2007

A method based on capillary electrophoresis with electrochemical detection has been employed for the separation and determination of homocysteine, cysteine, reduced glutathione, ascorbic acid and uric acid. Effects of several important factors such as the acidity and concentration of the running buffer, separation voltage, injection time and detection potential were investigated to acquire the optimum conditions. The detection electrode was a 500 µm diameter platinum disk electrode at a working potential of +1.05 V (vs saturated calomel electrode). The five analytes were well separated within 10 min in a 50 cm long fused silica capillary at a separation voltage of 18 kV in a 100 mm phosphate buffer (pH 7.8). The relation between peak current and analyte concentration was linear over about 3 orders of magnitude with the detection limits (S/N = 3) ranging from 0.83 to 2.58 µm. The proposed method was successfully applied to determine cysteine, reduced glutathione, ascorbic acid and uric acid in human whole blood and rat brain tissues with satisfactory assay results and should find a wide range of bioanalytical applications. Copyright © 2007 John Wiley & Sons, Ltd.
Role of regulator of G‐protein signaling 2 (RGS2) in periodontal ligament cells under mechanical stress
Authors: de Araujo Rui M. Santos , Oba Yasuo , Moriyama Keiji
Published: February 2007

Mechanical stress is thought to regulate the expression of genes in the periodontal ligament (PDL) cells. Using a microarray approach, we recently identified a regulator of G‐protein signaling 2 (RGS2) as an up‐regulated gene in the PDL cells under compressive force. The RGS protein family is known to turn off G‐protein signaling. G‐protein signaling involves the production of cAMP, which is thought to be one of the biological mediators in response to mechanical stress. Here, we investigated the role of RGS2 in the PDL cells under mechanical stress. PDL cells derived from the ligament tissues of human premolar teeth were cultured in collagen gels and subjected to static compressive force. Compressive force application time‐dependently enhanced RGS2 expression and intracellular cAMP levels. To examine the interrelationship between RGS2 and cAMP, the PDL cells were treated with 2′,5′‐dideoxyadenosine (DDA), an inhibitor of adenyl cyclase, or antisense S‐oligonucleotide (S‐ODN) to RGS2 under compressive force. DDA dose‐dependently inhibited RGS2 stimulated by compressive force. Blockage of RGS2 by antisense S‐ODN elevated the cAMP levels compared with controls. These results indicate that cAMP stimulates RGS2 expression, which in turn leads to a decrease in the cAMP production by inactivating the G‐protein signaling in the mechanically stressed PDL cells. Copyright © 2007 John Wiley & Sons, Ltd.
QTc‐interval abnormalities in a forensic population
Authors: Girgis Sobhi , Huckstep Bernard , Oakley Janette , Ferriter Michael , Nikolaou Vassilis
Published: February 2007

Background Antipsychotic drugs have been linked to sudden death among psychiatric patients, with a suggestion that prolongation of the QT‐interval detectable on a standard electrocardiogram may be linked to fatal cardiac arrhythmias in these circumstances. Patients in secure forensic psychiatric facilities may be particularly likely to be on high‐dose antipsychotic medication, and yet, as far as the authors are aware, no study of QT‐intervals among such patients has been reported.

Aim To investigate the prevalence of QT‐interval abnormalities and associated known risk factors for fatal cardiac arrhythmias in a sample of forensic patients.

Method Participants had a 12‐lead electrocardiogram taken at 50 mm/s. Information was collected on their age, gender, psychiatric diagnosis, history of cardiovascular, liver and kidney diseases, and smoking, on all medications and on history of seclusion over the previous 12 months. Analysis was carried out using binary logistic regression.

Results Lower rates of QT‐interval abnormalities than might be expected for this population were found. It was also found that a high dose of antipsychotics was associated with QTc prolongation (Adjusted OR = 9.5, 95% CI 2.6–34.2), a result consistent with previous literature.

Conclusion Forensic patients need not be at increased risk of QTc abnormality provided risk factors are properly managed. A high dose of antipsychotic medication increases the risk of QTc prolongation. Copyright © 2007 John Wiley & Sons, Ltd.
What do you think you're looking at? Investigating social cognition in young offenders
Authors: Jones Alice P. , Forster Alice S. , Skuse David
Published: February 2007

Aim This small study was designed to assess the nature and severity of social‐cognitive deficits in antisocial adolescents.

Method Thirty‐seven boys aged 15–18 from a Young Offenders Institute and Community College participated. They were asked to complete a test of general intellectual ability and self‐rating of social competence as well as tasks from the Skuse Schedules for the Assessment of Social Intelligence.

Results Young offenders were poor at recognizing the facial expression of anger, regardless of intellectual ability. They could not accurately identify the direction of another's eye gaze. Their performance on theory of mind tasks, however, was unimpaired.

Conclusion These preliminary findings imply selective impairment in the cognitive appraisal of threat, which may contribute to social maladjustment. Further such study of social cognition among young offenders is indicated. Copyright © 2007 John Wiley & Sons, Ltd.
Mortality among homicide offenders: a retrospective population‐based long‐term follow‐up
Authors: Lindqvist Per , Leifman Anders , Eriksson Anders
Published: February 2007

Background Empirical data on homicide and homicide offenders are needed in the ongoing discussion on violence and crime prevention. One issue, insufficiently investigated, is the post‐trial life course of homicide offenders.

Aim To examine whether the mortality rate, as well as cause and manner of death, of homicide offenders is different from the general population.

Method An incidence cohort of Swedish homicide offenders from 1970 to 1980 (n = 153) was re‐examined by computerized record linkage with the National Cause‐of‐Death Register for the period between trial and 1 October 2002, i.e. 22–32 years after the offence. Death certificates were analysed, and standard procedures for calculating Standard Mortality Rate (SMR) and survival analysis were employed.

Results Half of the study subjects had died by 2002. The overall mortality rate was about three times higher than that of the general population. In particular, the risk of suicide was salient.

Implications It can be argued that offenders' self‐neglect and self‐contempt merge with public and professional views, predisposing to an increased risk of premature death. Copyright © 2007 John Wiley & Sons, Ltd.
The validity of the Violence Risk Appraisal Guide (VRAG) in predicting criminal recidivism
Authors: Kröner Carolin , Stadtland Cornelis , Eidt Matthias , Nedopil Norbert
Published: February 2007

Introduction The VRAG is an actuarial risk assessment instrument, developed in Canada as an aid to estimating the probability of reoffending by mentally ill offenders.

Aim To test the predictive validity of the VRAG with a German sample.

Method The predictive validity of the VRAG was tested on a sample of 136 people charged with a criminal offence and under evaluation for criminal responsibility in the forensic psychiatry department at the University of Munich in 1994–95. The predicted outcome was tested by means of ROC analysis for correlation with the observed rate of recidivism between discharge after the 1994–95 assessment and the census date of 31 March 2003. Recidivism rate was calculated from the official records of the National Conviction Registry.

Results Just over 38% of the sample had reoffended by 2003. Their mean time‐at‐risk was 58 months (SD 3.391; range 0–115 months). The VRAG yielded a high predictive accuracy in the ROC analysis with an AUC of 0.703. For a constant time‐at‐risk < = 7 years, the predicted probability and observed rates of recidivism correlated significantly with Pearson's r = 0.941.

Conclusions The validity of the VRAG was replicated with a German sample. The VRAG yielded good predictive accuracy, despite differences in sample and outcome variables compared with its original sample. Copyright © 2007 John Wiley & Sons, Ltd.
Balloon angioplasty for branch pulmonary artery stenosis—Cutting balloons
Authors: De Giovanni Joseph V.
Published: February 2007

Pulmonary artery stenosis can cause right ventricular strain but intrapulmonary lesions are inaccessible to surgery; moreover, some are also resistant to high pressure balloon angioplasty. An alternative is the use of microsurgical devices mounted on balloons for transvenous delivery, including cutting balloons. The current literature is sparse but seems to indicate a role for cutting balloons in specific situations. The higher cost of these devices does not merit routine use instead of high pressure balloons but a randomised controlled study is underway to address this issue. Until the results of this become available, the role of cutting balloons for pulmonary artery stenosis remains limited to specific situations. The recommendations for the safe use of these devices must be adhered to by all operators. © 2007 Wiley‐Liss, Inc.
Selective Catalysis and Nanoscience: An Inseparable Pair
Authors: Zecchina Adriano , Groppo Elena , Bordiga Silvia
Published: February 2007

Selective catalysts can be considered as nanomachines designed to perform the synthesis of molecules with high reaction activity and high selectivity. These properties arise from a precise control of the structure of the active sites, of the three‐dimensional environment and of their relationship. In both homogeneous and heterogeneous catalysts the active site three‐dimensional environment ensemble is always a complex structure resembling the tuneable structure of enzymes, which are the most efficient catalysts optimized by nature over billions of years. To illustrate this concept the structure of a few homogeneous and heterogeneous catalysts for alkenes hydrogenation and for olefin polymerization are chosen and discussed as examples.
Carbon Dioxide Hydrogenation Catalyzed by a Ruthenium Dihydride: A DFT and High‐Pressure Spectroscopic Investigation
Authors: Urakawa Atsushi , Jutz Fabian , Laurenczy Gábor , Baiker Alfons
Published: February 2007

Reaction pathways during CO2 hydrogenation catalyzed by the Ru dihydride complex [Ru(dmpe)2H2] (dmpe=Me2PCH2CH2PMe2) have been studied by DFT calculations and by IR and NMR spectroscopy up to 120 bar in toluene at 300 K. CO2 and formic acid readily inserted into or reacted with the complex to form formates. Two formate complexes, cis‐[Ru(dmpe)2(OCHO)2] and trans‐[Ru(dmpe)2H(OCHO)], were formed at low CO2 pressure (<5 bar). The latter occurred exclusively when formic acid reacted with the complex. A RuH⋅⋅⋅HOCHO dihydrogen‐bonded complex of the trans form was identified at H2 partial pressure higher than about 50 bar. The trans form of the complex is suggested to play a pivotal role in the reaction pathway. Potential‐energy profiles along possible reaction paths have been investigated by static DFT calculations, and lower activation‐energy profiles via the trans route were confirmed. The H2 insertion has been identified as the rate‐limiting step of the overall reaction. The high energy of the transition state for H2 insertion is attributed to the elongated RuO bond. The H2 insertion and the subsequent formation of formic acid proceed via Ru(η2‐H2)‐like complexes, in which apparently formate ion and Ru+ or Ru(η2‐H2)+ interact. The bond properties of involved Ru complexes were characterized by natural bond orbital analysis, and the highly ionic characters of various complexes and transition states are shown. The stability of the formate ion near the Ru center likely plays a decisive role for catalytic activity. Removal of formic acid from the dihydrogen‐bonded complex (RuH⋅⋅⋅HOCHO) seems to be crucial for catalytic efficiency, since formic acid can easily react with the complex to regenerate the original formate complex. Important aspects for the design of highly active catalytic systems are discussed.
Feststoffextraktion
Authors: Bart H.‐J. , Schmidt M.
Published: February 2007

Die Feststoffextraktion aus Pflanzen ermöglicht eine Gewinnung unter Strukturerhaltung komplexer chemischer Verbindungen. Am Beispiel der Extraktion von Triterpensäuren aus Salbei werden dazu mögliche Extrahierphasen (überkritische, tensidhaltige etc.) diskutiert. Klassische organische Lösungsmittelgemische zeigen die höchsten Extraktionskapazitäten, doch kann eine Verbesserung der Extraktionsausbeute (Löslichkeit, Selektivität) durch Zusätze (Lösungsvermittler, Puffer etc.) erreicht werden.
Biokraftstoffe – Eine langfristige Energiequelle
Authors: Wille A.
Published: February 2007

Bei der Entwicklung und dem Einsatz von Biokraftstoffen handelt es sich um ein ebenso spannendes wie weitgefächertes Thema, das in den letzten Jahren eine Dynamik erfahren hat, die einen ganzen Wissenschafts‐ und Wirtschaftszweig geschaffen hat. Dieser wird durch die Verknappung der globalen fossilen Energieträgerbasis für eine energiehungrige Weltgemeinschaft angetrieben. Eine Vielzahl von Technologien und Einsatzmöglichkeiten von Biomasse ist vonnöten, um die Energiematrix sinnvoll und nachhaltig zu ergänzen. Viele Forschungsvorhaben kreisen heute um die Frage nach der Weiterentwicklung der Biokraftstoffe, um von der ersten zur zweiten Generation zu kommen. Dafür ist es notwendig, technisch machbare und makroökonomisch verträgliche Verfahren zu entwickeln, die nicht nur die Energieausbeute des Kohlenstoffspeichers Biomasse weiter steigern, um die fossile Energie zu ergänzen und teilweise zu ersetzen, sondern auch, um damit einen Beitrag zur Verbesserung des globalen Klimas zu ermöglichen.
Multidisciplinary frontiers in breast cancer management
Authors: Singletary S. Eva
Published: February 2007

The current paradigm of breast cancer management may be altered significantly over the coming years by the adoption of new treatment schema and devices outside of the surgical arena. New advances in breast cancer imaging will improve our ability to detect early‐stage disease but also will assist in monitoring treatment outcomes and support the development of nonsurgical ablation techniques. These advances, some already in use, include a 3‐dimensional adaptation of digital mammography, color Doppler ultrasonography that can visualize neovascularization in growing tumors, contrast‐enhanced magnetic resonance imaging with improved accuracy for the detection of occult cancers, a specialized approach to positron emission tomography designed for use on the breast, and the development of nanoparticle contrast agents that can be visualized with near‐infrared light. Systemic therapy, which revolutionized breast cancer management in the last half of the 20th century, is being reconceptualized, with attention turning to adjusting the timing of chemotherapy. Dose‐dense regimens are being tested, and there also is interest in so‐called metronomic chemotherapy in which very low doses are given on a very frequent schedule, resulting in reduced toxicity and treatment outcomes that reflect an antiangiogenic mode of action. Finally, the possibility of a breast cancer vaccine continues to intrigue and excite physicians and patients alike, with the promise of enlisting the body's own immune system to seek out and destroy cancer cells and/or prevent the development of future disease. It will be important for surgeons to stay aware of all developments that may improve the care of their patients and to be true surgical oncologists rather than merely surgical technicians. Cancer 2007. © 2007 American Cancer Society.
A novel circuit element and its application in signal amplification
Authors: Gift Stephan J. G. , Maundy Brent
Published: February 2007

A novel IC‐based current amplifier configuration for signal‐processing applications that can be configured using commercially available integrated circuit elements is presented. The circuit is accurate, has a wide bandwidth and can drive grounded loads. It utilizes a CCII+ type current conveyor with its input circuit in the feedback loop of a current feedback amplifier (CFA). In the current amplifying mode, the circuit has a low input impedance over a broad frequency range which never rises above the low input impedance of the inverting input of the associated CFA. Experimental results obtained using AD844s confirm the results derived. Copyright © 2007 John Wiley & Sons, Ltd.
An extended core‐based framework for delay‐constrained group communication
Authors: Karaman Ayşe , Hassanein Hossam
Published: February 2007

Multipoint communications is the simultaneous transmission of data streams from a number of sources to a set of receivers in a group according to predetermined metrics. The core‐based approach in multipoint communication enhances potential solutions in terms of quality‐of‐service (QoS)‐efficiency and feasibility of the results in inter and intra‐domain routing. In this paper, we first analyse the solution space for constrained multipoint communication problems under the core‐based approach. We show that the range of solutions examined by the models proposed to date is restricted to a subset of the entire solution space, which restricts the potential efficiency of the results. We propose SPAN, a core‐based framework processing on our identified extended solution space for constrained multi‐source group applications. SPAN consists of core selection and tree construction as two modular components complimenting one another to achieve more efficient solutions in distributed processing. SPAN is also asymmetric, hence potentially operates in domains in which link weights are not necessarily equal in both directions. We analyse the computational and message complexity of our framework and show its feasibility for distributed deployment. Our performance results show that SPAN consistently outperforms its counterparts in the literature in terms of cost and QoS‐efficiency. Copyright © 2007 John Wiley & Sons, Ltd.
Pak1 regulates dendritic branching and spine formation
Authors: Hayashi Kanehiro , Ohshima Toshio , Hashimoto Mitsuhiro , Mikoshiba Katsuhiko
Published: February 2007

The serine/threonine kinase p21‐activated kinase 1 (Pak1) modulates actin and microtubule dynamics. The neuronal functions of Pak1, despite its abundant expression in the brain, have not yet been fully delineated. Previously, we reported that Pak1 mediates initiation of dendrite formation. In the present study, the role of Pak1 in dendritogenesis, spine formation and maintenance was examined in detail. Overexpression of constitutively active‐Pak1 in immature cortical neurons increased not only the number of the primary branching on apical dendrites but also the number of basal dendrites. In contrast, introduction of dominant negative‐Pak caused a reduction in both of these morphological features. The length and the number of secondary apical branch points of dendrites were not significantly different in cultured neurons expressing these mutant forms, suggesting that Pak1 plays a role in dendritogenesis. Pak1 also plays a role in the formation and maintenance of spines, as evidenced by the altered spine morphology, resulting from overexpression of mutant forms of Pak1 in immature and mature hippocampal neurons. Thus, our results provide further evidence of the key role of Pak1 in the regulation of dendritogenesis, dendritic arborization, the spine formation, and maintenance. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007.
Kit‐like immunoreactivity in the zebrafish gastrointestinal tract reveals putative ICC
Authors: Rich A. , Leddon S.A. , Hess S.L. , Gibbons S.J. , Miller S. , Xu X. , Farrugai G.
Published: February 2007

Gastrointestinal (GI) motility results from the coordinated actions of enteric neurons, interstitial cells of Cajal (ICC), and smooth muscle cells. The GI tract of the zebrafish has a cellular anatomy that is essentially similar to humans. Although enteric nerves and smooth muscle cells have been described, it is unknown if ICC are present in the zebrafish. Immunohistochemistry and PCR were used determine expression for the zebrafish Kit orthologue in the zebrafish gastrointestinal tract. Cells displaying Kit‐like immunoreactivity were identified in the muscular layers of the adult zebrafish gastrointestinal tract. Two layers of Kit‐positive cells were identified, one with multipolar cells located between the longitudinal and circular smooth muscle layers and one with simple bipolar cells located deep in the circular muscle layer. Primers specifically designed to amplify mRNA coding for two zebrafish kit genes, kita and kitb, and two kit ligands, kitla and kitlb, amplified the expected transcript from total RNA isolated from zebrafish GI tissues. The Sparse mutant, a kita null mutant, showed reduced contraction frequency and increased size of the GI tract indicating a functional role for kita. These data establish the presence of a cellular network with Kit‐like immunoreactivity in the myenteric plexus region of the zebrafish GI tract, adjacent to enteric neurons. Expression of kita and kitb, and the ligands kitla and kitlb, were verified in the adult GI tract. The anatomical arrangement of the Kit‐positive cells strongly suggests that they are ICC. Developmental Dynamics 236:903–911, 2007. © 2007 Wiley‐Liss, Inc.
Functional role of transforming growth factor‐β type III receptor during palatal fusion
Authors: Nakajima Akira , Ito Yoshihiro , Asano Masatake , Maeno Masao , Iwata Koichi , Mitsui Narihiro , Shimizu Noriyoshi , Cui Xiao‐Mei , Shuler Charles F.
Published: February 2007

The molecular regulation of palatogenesis continues to be an active area of investigation to provide a foundation for understanding the molecular etiology of cleft palate. Transforming growth factor (TGF) ‐β type III receptor (TβR‐III) has been shown to be specifically expressed in the medial edge epithelium at critical stages of palatal shelf adherence during palatogenesis. The aim of this study was to examine TβR‐III mRNA localization and expression levels in vivo and to determine the requirement for TβR‐III expression during palatal fusion in vitro. TβR‐III gene expression was analyzed by in situ hybridization in tissue specimens and real‐time reverse transcriptase‐polymerase chain reaction using specific cells in the palatal shelf isolated by laser capture microdissection. TβR‐III was knocked down in embryonic day (E) 13 palatal shelves in organ culture. Palatal shelf organ cultures were treated with small interfering RNA (siRNA) at final concentrations of 300, 400, and 500 nM, respectively. The treatment with siRNA specific for TβR‐III decreased the amount of protein by approximately 75%. The reduction in TβR‐III resulted in a delay in the process of palatal fusion compared with control. The protein expression of phospho‐Smad2 was decreased in the TβR‐III siRNA group. In addition, palatal organ cultures treated with TβR‐III siRNA + rhTGF‐β3 completely fused by 72 hr in vitro. These results support our hypothesis that TβR‐III has a critical role in the process of palatal fusion. Developmental Dynamics 236:791–801, 2007. © 2007 Wiley‐Liss, Inc.
Spectrum of ENU‐induced mutations in phenotype‐driven and gene‐driven screens in the mouse
Authors: Barbaric Ivana , Wells Sara , Russ Andreas , Dear T. Neil
Published: February 2007

N‐ethyl‐N‐nitrosourea (ENU) mutagenesis in mice has become a standard tool for (i) increasing the pool of mutants in many areas of biology, (ii) identifying novel genes involved in physiological processes and disease, and (iii) in assisting in assigning functions to genes. ENU is assumed to cause random mutations throughout the mouse genome, but this presumption has never been analyzed. This is a crucial point, especially for large‐scale mutagenesis, as a bias would reflect a constraint on identifying possible genetic targets. There is a significant body of published data now available from both phenotype‐driven and gene‐driven ENU mutagenesis screens in the mouse that can be used to reveal the effectiveness and limitations of an ENU mutagenesis approach. Analysis of the published data is presented in this paper. As expected for a randomly acting mutagen, ENU‐induced mutations identified in phenotype‐driven screens were in genes that had higher coding sequence length and higher exon number than the average for the mouse genome. Unexpectedly, the data showed that ENU‐induced mutations were more likely to be found in genes that had a higher G + C content and neighboring base analysis revealed that the identified ENU mutations were more often directly flanked by G or C nucleotides. ENU mutations from phenotype‐driven and gene‐driven screens were dominantly A:T to T:A transversions or A:T to G:C transitions. Knowledge of the spectrum of mutations that ENU elicits will assist in positional cloning of ENU‐induced mutations by allowing prioritization of candidate genes based on some of their inherent features. Environ. Mol. Mutagen., 2007. © 2007 Wiley‐Liss, Inc.
The co‐morbidity of eating disorders and anxiety disorders: a review
Authors: Swinbourne Jessica M. , Touyz Stephen W.
Published: February 2007

Objective

To critically review the literature examining the co‐morbidity between eating disorders and anxiety disorders.

Method

A review of the literature on the co‐morbidity between anorexia nervosa, bulimia nervosa and eating disorders not otherwise specified and the anxiety disorders of OCD, PTSD, social anxiety, GAD, panic and agoraphobia.

Results

Of the empirical studies undertaken, it is clear that anxiety disorders are significantly more frequent in subjects with eating disorders than the general community. Researchers have shown that often anxiety disorders pre‐date eating disorders, leading to a suggestion that early onset anxiety may predispose individuals to developing an eating disorder. To date however, the research presents strikingly inconsistent findings, thus complicating our understanding of eating disorder and anxiety co‐morbidity. Furthermore, despite indications that eating disorder prevalence amongst individuals presenting for anxiety treatment may be high, there is a distinct lack of research in this area.

Discussion

This review critically examines the available research to date on the co‐morbidity of eating disorders and anxiety disorders. Some of the methodological limitations of previous research are presented, in order to highlight the issues which warrant further scientific investigation in this area. Copyright © 2007 John Wiley & Sons, Ltd and Eating Disorders Association.
The experience of ‘feeling fat’ in women with anorexia nervosa, dieting and non‐dieting women: an exploratory study
Authors: Cooper Myra J. , Deepak Kavita , Grocutt Elizabeth , Bailey Emma
Published: February 2007

Objective

To provide a preliminary, systematic exploration of some features associated with the experience of ‘feeling fat’.

Method

Women with anorexia nervosa (N = 16), women who were dieting (N = 15) and non‐dieting women (N = 17) took part in a semi‐structured interview.

Results

Feeling fat was common in all three groups of women. It was associated with distress, negative emotions, internal and external body sensations, images in a range of modalities, negative self beliefs and a first memory of feeling fat. Differences specifically characteristic of those with anorexia nervosa were identified, including feeling fatter, greater associated distress, more negative emotions, greater ‘emotional’ belief in cognitions, a richer experience, an earlier first memory, greater strength of negative self beliefs and a link to restricting behaviour. Some qualitative data are reported.

Conclusions

The experience of feeling fat can be ‘unpacked’ in a way that may be useful in cognitive therapy for those with anorexia nervosa. Copyright © 2007 John Wiley & Sons, Ltd and Eating Disorders Association.
Feasibility and acceptability of CD‐ROM‐based cognitive‐behavioural treatment for binge‐eating disorder
Authors: Shapiro Jennifer R. , Reba‐Harrelson Lauren , Dymek‐Valentine Maureen , Woolson Sandra L. , Hamer Robert M. , Bulik Cynthia M.
Published: February 2007

We compared preliminary feasibility and acceptability of CD‐ROM‐delivered CBT for overweight individuals with binge‐eating disorder (BED) to 10 weekly group CBT sessions (Group) and to a waiting list control (WL). Attrition was numerically greater in the Group than the CD‐ROM condition; although only Group differed significantly from WL in dropout rates. Those in the CD‐ROM condition reported continued use of their CD‐ROM after treatment. Also, the majority of WL participants elected to receive CD‐ROM over Group treatment at the end of the waiting period. Preliminarily, no significant differences emerged across the active treatment groups on most outcome measures. However, there was a significantly greater decline in binge days in the two active groups relative to WL. CD‐ROM appears to be an acceptable and at least initially preferred method of CBT delivery for overweight individuals with BED. Copyright © 2007 John Wiley & Sons, Ltd and Eating Disorders Association.
2‐Dimensional code design for an optical CDMA system with a parallel interference cancellation receiver
Authors: Morelle Mikaël , Goursaud Claire , Julien‐Vergonjanne Anne , Aupetit‐Berthelemot Christelle , Cances Jean‐Pierre , Dumas Jean‐Michel
Published: February 2007

The objective of this paper is to design a two‐Dimensional Optical Code Division Multiple Access system (2D‐OCDMA) for application in access networks, with coding and decoding functions performed by electronic devices. We present a new construction method of Multi‐Wavelength Optical Orthogonal Codes (MWOOC), which permits a high flexibility in the code parameters choice. This work evaluates in the noiseless case, the MWOOC potentialities for two receiver structures: a Conventional Correlation Receiver (CCR) and a Parallel Interference Cancellation receiver (PIC). We show that with a PIC receiver, it is possible to design two‐Dimensional codes that respect the access specifications. Copyright © 2007 John Wiley & Sons, Ltd.
Throughput performance of Hybrid ARQ schemes with packet and code combining for DS‐CDMA downlink systems using orthogonal spreading sequences
Authors: Boujemâa Hatem , Bahri Mohamed Wissem El , Siala Mohamed
Published: February 2007

In this paper, we evaluate the throughput performance of Automatic Repeat reQuest (ARQ) and HARQ I, with packet combining, and HARQ II, with code combining, using convolutional codes for DS‐CDMA downlink systems employing a Rake receiver. The different user packets are code multiplexed using a set of orthogonal variable spreading factor sequences. The analysis is carried out in two extreme scenarios, with either a constant or a packet‐by‐packet independent multipath fading channel during the different transmissions. The obtained results are valid for any multipath intensity profile of the channel and take simultaneously into account AWGN noise, path gains estimation noise, intersymbol interference and multiuser interference. Copyright © 2008 John Wiley & Sons, Ltd.