bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive evolution of mammalian aromatases: lessons from Suiformes
Authors: Conley A. J. , Corbin C. J. , Hughes A. L.
Published: April 2008

Estrogen synthesis evolved in chordates to control reproduction. The terminal enzyme in the cascade directly responsible for estrogen synthesis is aromatase cytochrome P450 (P450arom) encoded by the CYP19 gene. Mammals typically have a single CYP19 gene but pigs, peccaries and other Suiformes have two or more resulting from duplication in a common ancestor. Duplication of CYP genes in the steroid synthetic cascade has occurred for only one other enzyme, also terminal, 11β‐hydroxylase P450 (P450c11). P450arom and P450c11 share common substrates and even physiological functions as possible remnants from a common P450 progenitor, perhaps an ancestral P450arom, which is supported by phylogenetic analysis. Conserved tissue‐specific expression patterns of P450arom paralogs in placenta and gonads of pigs and peccaries suggest how functional adaptation may have proceeded divergently and influenced adopted reproductive strategies including ovulation rate and litter size. Data suggest that the porcine placental paralog evolved catalytically to protect female conceptuses from testosterone produced by male siblings; the gonadal paralog to synthesize a novel, nonaromatizable testosterone metabolite (1OH‐testosterone) that may increase ovulation rate. This would represent a coevolution facilitating litter bearing as pigs diverged from peccaries. Evidence of convergence between the peccary CYP19 genes and lower tissue expression may therefore represent initiation of loss of the functional paralogs. Studies on the Suiforme aromatases provide insights into the evolution of the steroidogenic cascade and metabolic pathways in general, how it translates into physiological adaptations (altered reproductive strategies for instance), and how duplicated genes become stabilized or disappear from genomes. J. Exp. Zool. 311A:346–357, 2009. © 2008 Wiley‐Liss, Inc.
The role of the state in the Turkish earthquake of 1999
Authors: Jacoby Tim , Özerdem Alpaslan
Published: April 2008

This paper seeks to contextualise the 1999 Turkish earthquake within the institutional structure of Turkey's development. Particularly focussed upon the role—and culpability—of the state in the disaster, it outlines a number of key continuities within Turkey's political tradition. In all, it argues that Ankara's inadequate response can be understood both in terms of the persistence of these older social structures and in a more recent weakening of the public sector. Despite a pronounced sense of instrumental activism which emerged in the immediate aftermath of the earthquake, the result, it is concluded, is a perpetuation of both state insularity and a fragmented pattern of civil organisation. Copyright © 2008 John Wiley & Sons, Ltd.
The spleen contributes to stroke‐induced neurodegeneration
Authors: Ajmo Craig T. , Vernon Dionne O. L. , Collier Lisa , Hall Aaron A. , Garbuzova‐Davis Svitlana , Willing Alison , Pennypacker Keith R.
Published: April 2008

Stroke, a cerebrovascular injury, is the leading cause of disability and third leading cause of death in the world. Recent reports indicate that inhibiting the inflammatory response to stroke enhances neurosurvival and limits expansion of the infarction. The immune response that is initiated in the spleen has been linked to the systemic inflammatory response to stroke, contributing to neurodegeneration. Here we show that removal of the spleen significantly reduces neurodegeneration after ischemic insult. Rats splenectomized 2 weeks before permanent middle cerebral artery occlusion had a >80% decrease in infarction volume in the brain compared with those rats that were subjected to the stroke surgery alone. Splenectomy also resulted in decreased numbers of activated microglia, macrophages, and neutrophils present in the brain tissue. Our results demonstrate that the peripheral immune response as mediated by the spleen is a major contributor to the inflammation that enhances neurodegeneration after stroke. © 2008 Wiley‐Liss, Inc.
Neuronal coupling via connexin36 contributes to spontaneous synaptic currents of striatal medium‐sized spiny neurons
Authors: Cummings Damian M. , Yamazaki Irene , Cepeda Carlos , Paul David L. , Levine Michael S.
Published: April 2008

Gap junctions provide a means for electrotonic coupling between neurons, allowing for the generation of synchronous activity, an important contributor to learning and memory. Connexin36 (Cx36) is largely neuron specific and provides a target for genetic manipulation to determine the physiological relevance of neuronal coupling. Within the striatum, Cx36 is more specifically localized to the interneuronal population, which provides the main inhibitory input to the principal projection medium‐sized spiny neurons. In the present study, we examined the impact of genetic ablation of Cx36 on striatal spontaneous synaptic activity. Patch‐clamp recordings were performed from medium‐sized spiny neurons, the primary target of interneurons. In Cx36 knockout mice, the frequencies of both excitatory and inhibitory spontaneous postsynaptic currents were reduced. We also showed that activation of dopamine receptors differentially modulated the frequency of GABAergic currents in Cx36 knockout mice compared with their wild‐type littermates, suggesting that dopamine plays a role in altering the coupling of interneurons. Taken together, the present findings demonstrate that electrical coupling of neuronal populations is important for the maintenance of normal chemical synaptic interactions within the striatum. © 2008 Wiley‐Liss, Inc.
Surface protein patterns govern morphology, proliferation, and expression of cellular markers but have no effect on physiological properties of cortical precursor cells
Authors: Magnusson Anna K. , Linderholm Pontus , Vieider Christian , Ulfendahl Mats , Erlandsson Anna
Published: April 2008

The ability to differentiate and give rise to neurons, astrocytes, and oligodendrocytes is an inherent feature of neural stem cells, which raises hopes for cell‐based therapies of neurodegenerative diseases. However, there are many hurdles to cross before such regimens can be applied clinically. A considerable challenge is to elucidate the factors that contribute to neural differentiation. In this study, we evaluated the possibility of steering neuronal maturation by growing cortical precursor cells on microscale surface patterns of extracellular matrix (ECM) proteins. When the cells were encouraged to extend processes along lines of ECM proteins, they displayed a much more mature morphology, less proliferation capacity, and greater expression of a neuronal marker in comparison with cells grown in clusters on ECM dots. This implied that the growth pattern alone could play a crucial role for neural differentiation. However, in spite of the strikingly different morphology, when performing whole‐cell patch‐clamp experiments, we never observed any differences in the functional properties between cells grown on the two patterns. These results clearly demonstrate that morphological appearances are not representative measures of the functional phenotype or grade of neuronal maturation, stressing the importance of complementary electrophysiological evidence. To develop successful transplantation therapies, increased cell survival is critical. Because process‐bearing neurons are sensitive and break easily, it would be of clinical interest to explore further the differentiating capacity of the cells cultured on the ECM dot pattern, described in this article, which are devoid of processes but display the same functional properties as neurons with mature morphology. © 2008 Wiley‐Liss, Inc.
Mixture design optimization of extraction and mobile phase media for fingerprint analysis of Bauhinia variegata L.
Authors: Delaroza Fernanda , Scarminio Ieda Spacino
Published: April 2008

Two statistical mixture designs were used to optimize the proportions of solvents used in both the extraction medium and the reversed liquid chromatographic mobile phase to improve the quality of chromatographic fingerprints of Bauhinia variegata L extracts. For modeling, the number of peaks was used as a measure of fingerprint information. Three mobile phases, each with a chromatographic strength of two, gave good results. A methanol/water (77:23 v/v) mixture resulted in 17 peaks in the chromatographic fingerprint whereas acetonitrile/water (64.5:35.5 v/v) and methanol/acetonitrile/water (35:35:30 v/v/v) mixtures resulted in 18 and 20 peaks, respectively. The corresponding optimum solvent compositions to extract chemical substances for these three mobile phases were ethanol/acetone (25:75 v/v/v) and dichloromethane/acetone (70:30 v/v) mixtures, and pure dichloromethane, respectively. The mixture designs are useful for understanding the influence of different solvents on the strengths of the extraction medium and the mobile phase.
Analysis of amino acids in human vascular endothelial (ECV‐304) cells by microchip electrophoresis with fluorescence detection
Authors: Shi Baoxian , Huang Weihua , Cheng Jieke
Published: April 2008

A rapid and sensitive method was developed for the analysis of amino acids by microchip electrophoresis with Hg‐lamp excitation fluorescence detection. Fluorescein‐isothiocyanate (FITC) was chosen to estimate the sensitivity of this system, and the detection limit (S/N = 3) with FITC was 1.7 nM, which showed that the system was sensitive as well as simple. Two derivatizing agents, FITC and ortho‐phthalaldehyde (OPA) were employed to label amino acids and were compared in the same fluorescence detection system with an Hg lamp as the excitation source. The separation parameters were optimized in detail. Optimum separation of OPA‐labeled amino acids was obtained in less than 200 s with 20 mM borate buffer (pH 9.0) containing 20% acetonitrile and 10 mM β‐cyclodextrin. Detection limits for amino acids (alanine (Ala), taurine (Tau), glycine (Gly), glutamic acid (Glu), and aspartic acid (Asp)) of 0.38–1.0 μM were achieved. The method was successfully applied to analysis of amino acids in human vascular endothelial cells (ECV‐304). The average amount of amino acids in single ECV‐304 cells is estimated to be 5.84 fmol for Ala, 2.78 fmol for Tau, 1.15 fmol for Gly, 3.10 fmol for Glu, and 1.30 fmol for Asp.
Enantioselective HPLC resolution of synthetic intermediates of armodafinil and related substances
Authors: Nageswara Rao Ramisetti , Shinde Dhananjay D. , Kumar Talluri Murali V. N.
Published: April 2008

Armodafinil is a unique psychostimulant recently approved by the US Food and Drug Administration for the treatment of narcolepsy. The chromatographic resolution of its chiral intermediates including related substances in the total synthesis of armodafinil was studied on polysaccharide‐based stationary phases, viz. cellulose tris‐(3,5‐dimethylphenylcarbamate) (Chiralcel OD‐H) and amylose tris‐(3,5‐dimethylphenylcarbamate) (Chiralpak AD‐H) by HPLC. The effects of 1‐propanol, 2‐propanol, ethanol, and trifluoroacetic acid added to the mobile phase and of column temperature on resolution were studied. A good separation was achieved on cellulose‐based Chiralcel OD‐H column compared to amylose‐based Chiralpak AD‐H. The effects of structural features of the solutes and solvents on discrimination between the enantiomers were examined. Baseline separation with Rs >1.38 was obtained using a mobile phase containing n‐hexane–ethanol–TFA (75:25:0.15 v/v/v). Detection was carried out at 225 nm with photodiode array detector while identification of enantiomers was accomplished by a polarimetric detector connected in series. The method was found to be suitable not only for process development of armodafinil but also for determination of the enantiomeric purity of bulk drugs and pharmaceuticals.
Fast‐GC–conventional quadrupole mass spectrometry in essential oil analysis
Authors: Rubiolo Patrizia , Liberto Erica , Sgorbini Barbara , Russo Rossana , Veuthey Jean‐Luc , Bicchi Carlo
Published: April 2008

This study reports on the compatibility of a conventional quadrupole MS (qMS) as detector for Fast‐GC in terms of separation, identification, and quantitation when applied to the analysis of peppermint essential oil (e.o.), adopted as representative of this field. The influence of Fast‐GC carried out on a 10 m×0.1 mm id narrow bore column with temperature programmes from 20 to 60°C/min on the results of a qMS in total ion chromatograms (TIC) at different speeds (from 999 and 11 111 amu/s) and SIM modes was evaluated on ten differently abundant components characterizing peppermint e.o. Separation measure (S), peak capacity (n), and half height peak width were taken as separation parameters; match quality, number of scans per peak (NP), spectral skewing, and TIC area repeatability were used for identification. Quantitation was in SIM mode and NP, dwell time, SIM area repeatability and calibration curves, LOD, and LOQ of the selected components were measured. The results show that the peppermint e.o. markers can successfully be analysed qualitatively and quantitatively by F‐GC–qMS up to temperature programmes of 60°/min provided that a suitable scan speed is applied. Fast‐GC–qMS reduces analysis time by a factor greater than ten and gives results that are qualitatively reliable and quantitatively comparable to those obtained by conventional GC–qMS.
Preparation of Chitinous Compound/Gelatin Composite and Their Biological Application
Authors: Nagahama Hideaki , New Nitar , Jayakumar Rangasamy , Furuike Tetsuya , Tamura Hiroshi
Published: April 2008

Chitin, a natural abundant polysaccharide, have been investigated as prospected biochemical material due to its several biological advantages. It is insoluble in the most of the organic solvents due to its rigid crystalline structure. However, chitin regenerated hydrogel (RG) has been prepared by using the saturated calcium solvent system under mild conditions. And also, swelling hydrogel (SG) was prepared by using water. In this study, we prepared the suspension of chitinous hydrogel, and applied to fabricated the chitinous compound/gelatin composite sheets. Additionally, N‐acetyl D‐(+)‐glucosamine was added into some composite sheets. We investigated the mechanical properties and growth of NIH/3T3 fibroblast cell for the prepared composite sheet.
Ultraviolet Protection Characteristics of Silicone/Titanium Dioxide Composite Sheets
Authors: Seetapan Nispa , Panyathammaporn Thammarat
Published: April 2008

Silicone/titanium dioxide (TiO2) composite sheets were prepared from TiO2 particles and silicone elastomer by a compression‐molding process at 140 °C. The particles were produced through sol‐gel method, and emulsion technique consecutively. The prepared composite sheets with thickness of 0.8 mm had ultraviolet radiation protection property such that the transmission of ultraviolet (UV) B ray through the sheets was less than 1%. The UVA ray transmitted the sheets in the range of 0.02–4% at 320 nm and 2–43% at 400 nm, depending on the amount of TiO2 emulsion presented in the silicone elastomer. The composite sheets still remained transparent since the transmission of the visible light through the sheets was up to 60%. On the other hand, the transmissions of UVB ray, UVA ray, and visible light through the pure silicone elastomer sheets were in the range of 47–58%, 58–71%, and 71–88%, respectively. Comparable with silicone elastomer sheets, the addition of TiO2 emulsion resulted in the composite sheets with higher strain and lower modulus; however, these differences in tensile properties were up to the amount of the emulsion in the silicone elastomer.
Polymer‐Based Superhydrophobic Coating Fabricated from Polyelectrolyte Multilayers of Poly(allylamine hydrochloride) and Poly(acrylic acid)
Authors: Nimittrakoolchai On‐uma , Supothina Sitthisuntorn
Published: April 2008

Superhydrophobic films mainly based on poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) polyelectrolyte multilayer have been deposited onto cleaned glass substrate by a layer‐by‐layer dip coating method. 3 bilayers of the PAH and PAA was directly coated onto the substrate as an underlying layer for subsequent coating. Desired surface roughness on the polyelectrolyte bilayers was created by etching the bilayers in hydrochloric acid solution so as to create the open pore having suitable size at the surface. Then, nanoparticles such as SiO2 and TiO2 of various sizes were deposited onto the etched polyelectrolyte bilayers. Finally, the surfaces were further modified with semifluorinated silane followed by cross‐linking at 180 °C for 2 h to obtain desirable surface morphological features. The effect of etching time and addition of nanoparticles on surface morphology was investigated using an atomic force microscope (AFM). Wetting ability of the prepared film was determined by measuring water droplet contact angle using a goniometer. Adhesion between the superhydrophobic films and the substrate was evaluated by using a standard tape test method (D3359). The adhesion was improved by reducing the organic content in the films.
Ultrafine Electrospun Conducting Polymer Blend Fibers and Their Photoluminescence Properties
Authors: Chuangchote Surawut , Sagawa Takashi , Yoshikawa Susumu
Published: April 2008

Ultrafine poly(2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylene‐vinylene) (MEH‐PPV)/polyvinylpyrrolidone (PVP) blend fibers with the average diameters ranging from 625 nm to 1.46 µm were prepared by electrospinning of polymer blend solutions in the mixed solvent of chlorobenzene and methanol. The average diameter of fibers was found to decrease with initial increase in the applied electrical potential and composition of MEH‐PPV, reach a minimum value at an intermediate value, and increase with further increase in the applied electrical potential and composition of MEH‐PPV, while it was found to decrease with increasing collection distance. PVP was easily removed from MEH‐PPV/PVP fibers by the Soxhlet extraction, and after the removal of PVP at high composition of MEH‐PPV, pure MEH‐PPV fibers were obtained as a ribbon‐like structure aligned with wrinkled surface in fiber direction. The increase in MEH‐PPV composition and the removal of PVP from as‐spun MEH‐PPV/PVP fibers resulted in a significant blue‐shift in UV‐Vis absorption peak and red‐shift in PL peak.
Novel Interpenetrating Networks (IPNs) Hydrogels Prepared In Situ by Liquid‐Phase Photopolymerization
Authors: Yongmei Jiang , Yang Liu , Yun Ma , Xiaoli Liu , Zongyi Qin , Meifang Zhu , Adler H. J.
Published: April 2008

Novel interpenetrating networks (IPNs) hydrogels responsive to temperature were prepared in situ by liquid‐phase photopolymerization. The first network of the IPNs (poly isopropyl acrylamide) were formed with a special kind of hectorite (Laponite XLS) modified by tetrasodium pyrophosphate as cross‐linker and 2‐oxogultaric acid as photoinitiator. The samples were subsequently immersed in an acrylamide (AAm) aqueous solution for at least one day for preparing IPNs hydrogels, in which acrylamide aqueous solution containing N,N′‐Dimetyl acrylamide (MBAA) as cross‐linker and 2‐oxogultaric acid as photoinitiator. Then the second networks were in situ formed by introducing ultraviolet light irradiated PNIPAAm gels. The swelling/deswelling behaviors of IPNs hydrogels were measured. Compared with the corresponding nanocomposite PNIPAAm hydroges(NC hydrogels), chemically cross‐linked PNIPAAm and PAAm IPNs hydrogels, the results indicate that the new IPN hydrogel has a faster deswelling rate above its LCST (≈32 °C). The effect was explained as being an additional contribution of the PAAm chains in IPN hydrogels, which may act as a water‐releasing channel when the hydrophobic aggregation of PNIPA takes place.
Thermal Properties and Crystallization Behaviors of Polylactide and Its Enantiomeric Blends
Authors: Opaprakasit Pakorn , Opaprakasit Mantana
Published: April 2008

Thermal properties and crystallization behaviors of polylactide and its enantiomeric blends are investigated. DSC results demonstrate that only homopolymer crystallite is observed in PDLA and PLLA single polymers. A relatively stronger crystal structure, stereocomplex, can be achieved by mixing the two PLAs in a 1:1 ratio. For non‐equimolar blends, both types of crystallites are formed at lower temperature than that of the single polymer counterparts. The degree of reduction in crystallization temperature is dependent on the degree of deviation of blend content from the equimolar value and the mobility of the polymer chain. The composition of the two crystallite domains is also dependent on the blend content, where the stereocomplex content is maximized in a 1:1 blend, and decreases upon varying the mixing ratio from equimolar value. Infrared spectroscopy is employed to follow the crystallization mechanisms of the non‐equimolar blend. Results indicate a domination of stereocomplex formation band characteristics, despite evidences suggesting an existent of homopolymer crystallite formation, probably due to the involvement of CH··OC hydrogen bonding, which leads to larger change in dipole moment responsible for infrared transitions.
Preparation and Physico‐Chemical Characteristics of N‐Maleoyl Chitosan Films
Authors: Vanichvattanadecha Chutima , Supaphol Pitt , Rujiravanit Ratana
Published: April 2008

N‐Maleoyl chitosan (N‐MC), a water‐soluble derivative of chitosan, was synthesized by N‐carboxyacylation of chitosan and maleic anhydride. N‐MC films were prepared by solvent casting and kept in a desiccator for different time intervals in order to obtain N‐MC films with different degrees of cross‐linking. The swelling characteristic of N‐MC films was investigated. When the ageing time increased from 5 to 30 d, the swelling of the N‐MC films decreased from ∼475 to ∼160% and the weight loss decreased from ∼25 to ∼8%, corresponding to the increase in the cross‐linking density from 0.86 × 10−6 to 8.97 × 10−6 mol · cm−3. Additionally, the swelling behavior of the N‐MC films was influenced by changes in either the pH or the ionic strength of the media.
Synthesis and Characterization of UV‐Curable Poly(dimethylsiloxane) Dimethacrylate
Authors: Thavornyutikarn Boonlom , Janvikul Wanida
Published: April 2008

This paper presents a new route to the synthesis of UV‐curable poly(dimethylsiloxane) dimethacrylate (PDMSDMA). PDMSDMA was essentially prepared by modification of poly(dimethylsiloxane), bis(3‐aminopropyl) terminated (PDMS‐NH2) with methacrylic anhydride (MAA). The synthesized products were cured under UV in the presence of camphorquinone (CQ) used as a photoinitiator. The chemical structure of PDMSDMA samples was analyzed by FT‐IR and 1H‐NMR spectroscopy. The 1H‐NMR spectrum of PDMSDMA revealed new peaks at 3.20 ppm, corresponding to methylene protons in CH2NH, and 5.25 and 5.65 ppm, corresponding to vinylic protons in NHCOCCH3CH2. The chemical structure of the cured products and the degree of curing were determined by solid state 13C CP/MAS NMR and FT‐IR (Micro‐ATR) spectroscopy. Various parameters, such as concentration of methacrylic anhydride, amount of camphorquinone, and curing time, were studied.
Determination of Operating Conditions of Ethylene/1‐Octene Copolymerization Using Artificial Neural Network (ANN)
Authors: Anantawaraskul Siripon , Toungsetwut Mahapon , Pinyapong Ratchadaporn
Published: April 2008

An artificial neural network (ANN) is applied to determine appropriate parameters in copolymerization of ethylene and 1‐octene via metallocene catalytic system for producing a copolymer with desired chain microstructures. The polymerization parameters of interests are polymerization temperature, ethylene pressure, and the amount of hydrogen used. The ANN used is a feed‐forward network with a back propagation learning method and has a 5‐6‐6‐3 architecture. When comparing with both training and testing experimental data sets, it was found that ANN can provide a good guesstimation of polymerization parameters.
Physical and Electrical Properties of Chlorophyllin/Carboxymethyl Chitin and Chlorophyllin/Carboxymethyl Chitosan Blend Films
Authors: Thanpitcha Tuspon , Sirivat Anuvat , Jamieson Alexander M. , Rujiravanit Ratana
Published: April 2008

Blend films consisting of chlorophyllin dispersed in carboxymethyl chitin (CM‐chitin) and carboxymethyl chitosan (CM‐chitosan) were prepared by solution casting and characterized for their physical and electrical properties. Homogeneous films were obtained having chlorophyllin content up to 50 wt% in the CM‐chitin matrix and 30 wt% in the CM‐chitosan matrix. Agglomeration of chlorophyllin particles in the chlorophyllin/CM‐chitosan blend was observed, when chlorophyllin content reached 50 wt%. The electrical conductivity of CM‐chitosan was higher than that of CM‐chitin by approximately 2 orders of magnitude due to the higher content of amino polar groups. The electrical conductivity increased with increasing chlorophyllin content. The addition of metal ion salts improved the electrical conductivity of the blend films.
Electromechanical Responses of a Crosslinked Polydimethylsiloxane
Authors: Niamlang Sumonman , Sirivat Anuvat
Published: April 2008

A high molecular weight polydimethylsiloxane, PDMS, gel was prepared and investigated as an electroactive polymer actuator. Electromechanical properties of the PDMS gels were measured under an oscillatory shear mode at the temperature of 27 °C to determine the effects of crosslink ratio and electric field strength. The storage modulus, G′, of PDMS gel increases linearly with crosslink density but nonlinearly with electric field. The increase in the storage modulus with crosslink density is due to the increase in the number of junction points and strands. With increasing electric field strength, the storage modulus increases as the electric field induces dipole moments generating the electrostatic forces within the matrices. The gel with the crosslink ratio of 0.01 possesses the highest G′ sensitivity of 41% at 2 kV/mm. The temporal response of PDMS gels upon repeated applications of electric field strength of 2 kV/mm was investigated. For the crosslink PDMS (Nc/Nm = 0.01) system, at the electric field of 2 kV/mm, G′ immediately increases and rapidly reaches a steady‐state value. With electric field off, G′ decreases and nearly recovers its original value. The crosslinked PDMS (Nc/Nm = 0.01) is nearly a reversible system. Finally, we investigated the bending response of the PDMS films, suspended in silicone oil between copper electrodes. From the deformation data, we estimated the dielectrophoresis force, FD, to be a linear function of electric field strength.
Selective inhibitors of picornavirus replication
Authors: De Palma Armando M. , Vliegen Inge , De Clercq Erik , Neyts Johan
Published: April 2008

Picornaviruses cover a large family of pathogens that have a major impact on human but also on veterinary health. Although most infections in man subside mildly or asymptomatically, picornaviruses can also be responsible for severe, potentially life‐threatening disease. To date, no therapy has been approved for the treatment of picornavirus infections. However, efforts to develop an antiviral that is effective in treating picornavirus‐associated diseases are ongoing. In 2007, Schering‐Plough, under license of ViroPharma, completed a phase II clinical trial with Pleconaril, a drug that was originally rejected by the FDA after a New Drug Application in 2001. Rupintrivir, a rhinovirus protease inhibitor developed at Pfizer, reached clinical trials but was recently halted from further development. Finally, Biota's HRV drug BTA‐798 is scheduled for phase II trials in 2008. Several key steps in the picornaviral replication cycle, involving structural as well as non‐structural proteins, have been identified as valuable targets for inhibition. The current review aims to highlight the most important developments during the past decades in the search for antivirals against picornaviruses. © 2008 Wiley Periodicals, Inc. Med Res Rev, 28, No. 6, 823–884, 2008
Repopulation of donor cells from the recipient following extremity graft: Studies using the LACZ transgenic rat
Authors: Muramatsu Keiichi , Kuriyama Ryutaro , Taguchi Toshihiko
Published: April 2008

Cell traffic from the recipient into the graft, so called graft chimerism, appears to play a major role in graft acceptance. This study was conducted using LacZ transgenic rats to define recipient cell migration into whole‐limb grafts. Eighteen hind limb transplants were performed across LacZ+ transgenic and LacZ− rats. LacZ expression was evaluated by X‐gal staining. Intense LacZ expression was observed at the interfollicular epidermis in the skin component of LacZ− limb grafts 48 weeks after transplant. Muscle fibers and cartilage showed intense LacZ expression in LacZ+ limb grafts at 48 weeks but no expression in LacZ− grafts. Polymerase chain reaction studies confirmed the presence of the LacZ gene in the bone and skin of LacZ− limb grafts and in the muscle of LacZ+ grafts. Our results demonstrate that there is a gradual increase in repopulation of recipient cells in grafted skin and bone tissues, but muscle and cartilage tissues retain donor cell origin. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Complexation study of midazolam hydrochloride with β‐cyclodextrin: NMR spectroscopic study in solution
Authors: Ali Syed Mashhood , Upadhyay Santosh Kumar
Published: April 2008

1H NMR spectroscopic study of midazolam hydrochloride (MDL), β‐cyclodextrin (β‐CD) and their mixtures confirmed the formation of β‐CD‐MDL inclusion complex in aqueous solution. The stoichiometry of the complexes was determined by Scott's method to be 1:1, and the association constant (Ka) was calculated to be 108 M−1. It was confirmed on the basis of 2D ROESY spectral data that only a fluorine‐substituted aromatic ring acted as guest in complexation. Most of the aromatic signals of MDL exhibited induced shift changes as well as splitting, in the presence of β‐CD, indicating chiral differentiation of MDL by β‐CD. Copyright © 2008 John Wiley & Sons, Ltd.
Models of judicial administration and the independence of the judiciary: a comparison of Romanian self‐management and the Czech executive model
Authors: Smith B. C.
Published: March 2008

The Rule of Law is a necessary condition for economic, social and political development in countries undergoing transition from authoritarianism to democracy. The Rule of Law requires an independent judiciary, one that is impartial and insular. In Eastern Europe democratic transition has produced two models of judicial administration: judicial self‐management and the executive model. Romania is a case of the former, the Czech Republic an instance of the latter. Comparison of the two cases suggests that while political developments are important to the preservation of judicial independence, the consolidation of democracy and the organisation of the judiciary are in a reciprocal relationship. The organisation of the judiciary is necessary for the legislative transparency and oversight of the executive branch which in turn guards against the politicisation of judicial management, with its adverse consequences for the independence of the judiciary and ultimately the Rule of Law. Copyright © 2008 John Wiley & Sons, Ltd.
Intensive induction chemotherapy followed by high dose chemotherapy with autologous hematopoietic progenitor cell rescue in young children newly diagnosed with central nervous system atypical teratoid rhabdoid tumors
Authors: Gardner Sharon L. , Asgharzadeh Shahab , Green Adam , Horn Biljana , McCowage Geoffrey , Finlay Jonathan
Published: April 2008

Background

Central nervous system (CNS) atypical teratoid rhabdoid tumors (AT/RT) are rare tumors of childhood with a dismal prognosis. Historically, surgery and standard dose chemotherapy have resulted in a median survival of 8.5 months from diagnosis.

Methods

Thirteen children newly diagnosed with CNS AT/RT were treated with either the “Head Start I” (HS I) or “Head Start II” (HS II) regimens. Therapy included resection followed by five cycles of cisplatin, vincristine, cyclophosphamide, and etoposide. High dose methotrexate was added to each of the five induction courses in HS II. Consolidation for both regimens included carboplatin, thiotepa, and etoposide with autologous hematopoietic progenitor cell rescue (AHPCR).

Results

Six children, median age of 36 months, were treated on HS I between 1992 and 1997. Seven children, median age of 28 months, were treated on HS II between 1997 and 2002. One patient received craniospinal irradiation following AHPCR but prior to recurrence. There are presently three event‐free survivors 42+, 54+, and 67+ months following diagnosis; none received RT. All three survivors were enrolled on HS II. Eight patients died of disease (six on HS I); one patient died from infection; one patient died from secondary malignancy following treatment for recurrent AT/RT.

Conclusion

Three of seven children with CNS AT/RT treated on HS II have experienced long term remissions. Long term survival can be achieved in a subset of young children with CNS AT/RT following resection with the use of multi‐drug chemotherapy including high dose methotrexate and myeloablative chemotherapy without radiation therapy (RT). Pediatr Blood Cancer 2008;51:235–240. © 2006 Wiley‐Liss, Inc.
Risk of drug‐related problems for various antibiotics in hospital: assessment by use of a novel method
Authors: Blix Hege Salvesen , Viktil Kirsten K. , Moger Tron Anders , Reikvam Aasmund
Published: April 2008

Purpose

To investigate the use of antibiotics in hospitals, to explore drug‐related problems (DRPs) linked to antibiotics and to introduce a novel way of expressing the risks accompanying use of various antibiotics.

Methods

Patients from internal medicine departments in four Norwegian hospitals were prospectively included in 2002. Demographics, drugs used, medical history, laboratory data and clinical/pharmacological risk factors were recorded. DRPs were identified by clinical pharmacists and assessed in multidisciplinary hospital teams. A new term, the drug risk ratio, was established and defined as the number of times the antibiotic was associated with DRPs in relation to the number of times it was used.

Results

Out of the 668 patients included, 283 patients (42%) used antibiotics (AB users). AB users were older (76.2 vs. 73.9), used more drugs on admission (5.1 vs. 4.4) and had more DRPs (3.0 vs. 2.2) than non‐users.

The DRP categories no further need for drug, non‐optimal drug and non‐optimal dose were most frequently observed. The drug risk ratio, calculated for 12 antibiotic groups, was highest for aminoglycosides (0.77), β‐lactamase‐resistant penicillins (0.56), macrolides (0.54) and quinolones (0.48) and lowest for first‐ and third‐generation cephalosporins, 0.17 and 0.13, respectively.

Conclusions

Nearly half of the hospitalised patients were prescribed antibiotics and antibiotic associated DRPs occurred frequently. The drug risk ratio for the different antibiotic groups varied with a factor of six from the lowest to the highest. A high drug risk ratio would alert of antibiotics which require heightened awareness when going to be used in clinical practice. Copyright © 2008 John Wiley & Sons, Ltd.
Efficacy of the pyrethroid alpha‐cypermethrin against Bactrocera oleae populations from Greece, and improved diagnostic for an iAChE mutation
Authors: Margaritopoulos John T , Skavdis George , Kalogiannis Nikos , Nikou Dimitra , Morou Evangelia , Skouras Panagiotis J , Tsitsipis John A , Vontas John
Published: April 2008

BACKGROUND: The most important pest of olive orchards worldwide is the olive fruit fly Bactrocera oleae (Gmelin). Its control in Greece has been based on organophosphates (OPs), but their intense use has led to the development of resistance. A test previously developed to monitor the trait may not be as robust as originally thought. The pyrethroid alpha‐cypermethrin has recently been registered for bait sprays, as an alternative to OPs.

RESULTS: The susceptibility of 20 B. oleae populations to alpha‐cypermethrin was examined. Variation was observed in their response, with LD50 ranging from 0.14 to 3.28 ng insect−1 and resistance factors from 2.3 to 54.7. Resistance mechanisms were investigated. Cytochrome P450 monoxygenase activities showed an association with resistance. Sequences in the domain IIS4–IIS6 of the B. oleae para‐type sodium channel were also analysed, but no resistance‐associated mutations were identified. Finally, a novel diagnostic assay able to reliably monitor the frequency of the iAChE G488S resistance mutation was developed.

CONCLUSION: This is the first attempt to evaluate the efficacy of alpha‐cypermethrin against B. oleae from Greece. Data showed that it can be used effectively, but also highlighted the importance of continuous monitoring. The IIS4–IIS6 sodium channel region is the default area in which to look for resistance mutations if target‐site resistance to pyrethroids arises. The application of the novel iAChE molecular diagnostic may facilitate the introduction of pyrethroids alongside OPs currently in use. Copyright © 2008 Society of Chemical Industry
Synthesis of full length PB1‐F2 influenza A virus proteins from ‘Spanish flu’ and ‘bird flu’
Authors: Röder René , Bruns Karsten , Sharma Alok , Eissmann André , Hahn Friedrich , Studtrucker Nicole , Fossen Torgils , Wray Victor , Henklein Peter , Schubert Ulrich
Published: April 2008

The proapoptotic influenza A virus PB1‐F2 protein contributes to viral pathogenicity and is present in most human and avian isolates. Previous synthetic protocols have been improved to provide a synthetic full length H1N1 type PB1‐F2 protein that is encoded by the ‘Spanish flu’ isolate and an equivalent protein from an avian host that is representative of a highly pathogenic H5N1 ‘bird flu’ isolate, termed SF2 and BF2, respectively. Full length SF2, different mutants of BF2 and a number of fragments of these peptides have been synthesized by either the standard solid‐phase peptide synthesis method or by native chemical ligation of unprotected N‐ and C‐terminal peptide fragments. For SF2 chemical ligation made use of the histidine and the cysteine residues located in positions 41 and 42 of the native sequence, respectively, to afford a highly efficient synthesis of SF2 compared to the standard SPPS elongation method. By‐product formation at the aspartic acid residue in position 23 was prevented by specific modifications of the SPPS protocol. As the native sequence of BF2 does not contain a cysteine residue two different mutants of BF2 (Y42C) and BF2 (S47C) with appropriate cysteine exchanges were produced. In addition to the full length molecules, fragments of the native sequences were synthesized for comparison of their physical characteristics with those from the H1N1 human isolate A/Puerto Rico/8/34 (H1N1). All peptides were analyzed by mass spectrometry, 1H NMR spectroscopy, and SDS‐PAGE. The protocols allow the synthesis of significant amounts of PB1‐F2 and its related peptides. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Polarization dependent photoluminescence of charged quantum dot molecules
Authors: Stinaff E. A. , Ramanathan Swati , Wijesundara Kushal C. , Garrido Mauricio , Scheibner M. , Bracker A. S. , Gammon D.
Published: April 2008

We present the polarization dependent photoluminescence from coupled InAs quantum dots. We find polarization memory signatures consistent with those reported for single quantum dots. We also observe a continuous change in the polarization memory of the positively charged exciton as it changes charge configuration due to a hole tunnelling as a function of applied bias. This may provide a method for electrical control of the anisotropic exchange interaction which would be useful for spin manipulation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and optical properties of a‐plane AlN and Al rich AlN/AlxGa1–xN quantum wells grown on r‐plane sapphire substrates
Authors: Tahtamouni T. Al , Sedhain A. , Lin J. Y. , Jiang H. X.
Published: April 2008

A‐plane AlN epilayers and AlN/Al0.65Ga0.35N quantum wells (QWs) have been grown on r‐plane sapphire substrates by metal organic chemical vapor deposition. The growth surface and high crystalline quality were confirmed by x‐ray diffraction. Photoluminescence (PL) spectroscopy has been employed to probe the optical quality of the grown templates and QWs. The PL emission intensity of a‐plane AlN has been compared with that of c‐plane AlN. It was shown that the surface emission intensity of a‐plane AlN epilayers is compara‐ ble to that of c‐plane AlN. The PL emission properties of a‐ and c‐plane AlN/Al0.65Ga0.35N QWs were studied and compared. It was found that the low temperature PL characteristics of a ‐plane QWs are primarily governed by the quantum size effect, whereas those of c ‐plane QWs are significantly affected by the polarization fields. The PL decay time was found to be only weakly dependent on the well width, Lw, for a ‐plane QWs, whereas a strong dependence of the PL decay time on Lw was observed for c ‐plane QWs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improvement of GaN‐based LED with SiO2 photonic crystal on an ITO film by holographic lithography
Authors: Yen H. H. , Kuo H. C. , Yeh W. Y.
Published: April 2008

GaN‐based light‐emitting diode (LED) with SiO2 photonic crystals (PCs) structure made by holographic lithography on an indium‐tin‐oxide (ITO) film was fabricated. The PCs made on SiO2 but an ITO film both improves the light extraction efficiency of the GaN‐based LED and prevents the sheet resistance increasing of the ITO film from the dry etching damage. It was found that the forward voltage at 20 mA of the GaN‐based LED with SiO2 PCs on an ITO film was 1.9% higher than the GaN‐based LED with a planar ITO film only. The output power of GaN‐based LED with SiO2 PCs on an ITO film at 20mA was 17.1%, 26.5% and 125.3% higher than that of the GaN‐based LEDs with the planar SiO2/ITO, planar ITO or Ni/Au surface layers, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN vertical n‐p junctions prepared by Si ion implantation
Authors: Kocan M. , Umana‐Membreno G. A. , Recht F. , Baharin A. , Fichtenbaum N. A. , McCarthy L. , Keller S. , Menozzi R. , Mishra U. K. , Parish G. , Nener B. D.
Published: April 2008

We report on n‐p junctions formed on p/p+ GaN layers by silicon ion‐implantation. Post‐implantation damage removal was performed by annealing at 1260 °C in N2/NH3 ambient. Rectifying behaviour observed in current‐voltage measurements was associated with the n‐p junctions formed by ion‐implantation. In circular devices with a vertical n‐p junction topology, light emission under forward bias conditions was observed as a ring near the periphery of the n‐contact region, confirming the existence of an electrically active n‐p junction. The electrical‐characteristics of the n‐p diodes does not seem to be limited by the quality of the implanted junction but rather by the high spreading resistance of the underlying p+ contact layer, for which activation was incomplete. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sidewall epitaxial lateral overgrowth of nonpolar a‐plane GaN by metalorganic vapor phase epitaxy
Authors: Iida Daisuke , Kawashima Takeshi , Iwaya Motoaki , Kamiyama Satoshi , Amano Hiroshi , Akasaki Isamu
Published: April 2008

A major obstacle to achieving high‐performance devices using nonpolar a‐plane and m‐plane GaN is the existence of high‐density threading dislocations and stacking faults. Low‐defect‐density nonpolar plane GaN films were previously grown by sidewall epitaxial overgrowth using metalorganic vapor phase epitaxy [1, 2]. In this study, we control the growth‐rate ratio of Ga‐polar GaN to N‐polar GaN by adjusting the V/III ratio. It is possible to grow GaN only from the N‐face sidewall of grooves by maintaining a high V/III ratio, which reduces the number of coalescence regions on grooves and decreases the threading‐dislocation density and stacking‐fault density. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nitride based nanotransistors as new sources and detectors of THz radiations
Authors: Fatimy A. El , Teppe F. , Boubanga S. , Dyakonova N. , Gil B. , Coquillat D. , Seliuta D. , Valušis G. , Poisson M.‐A. , Morvan E. , Gaquiere Ch. , Theron D. , Cappy A. , Knap W.
Published: April 2008

The plasma waves in gated two‐dimensional electron gas have a linear dispersion law, similar to the sound waves. The transistor channel is acting as a resonator cavity for the plasma waves, which can reach frequencies in the Terahertz (THz) range for a sufficiently short gate length Field Effect Transistors (FETs). THz emission and detection by nanometer III‐V transistors have been recently reported. In this work we report on THz emission and detection by nanometer GaN/AlGaN HEMTs. In particular, we show that specific GaN properties allow to observe THz emission up to room temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport properties in n‐type AlGaN/AlN/GaN‐superlattices
Authors: Hertkorn J. , Brückner P. , Gao C. , Scholz F. , Chuvilin A. , Kaiser U. , Wurstbauer U. , Wegscheider W.
Published: April 2008

In order to improve the lateral conductivity in optoelectronic devices, we have investigated Si‐doped AlGaN/AlN/GaN‐superlattices. As a first step we performed calculations of the band structure of Al‐GaN/AlN/GaN modulation doped multi heterostructures. Based on these results we worked on optimizing the growth of low Al content (xAl ≤ 20%) superlattices by MOVPE. Several tens of abrupt and graded AlGaN/AlN/GaN‐layer pairs could be grown crack‐free on 2 μm thick n‐GaN layers deposited on sapphire substrates with AlN nucleation. By Van‐der‐Pauw Hall measurements, we determined that the lateral conductivity of a 1.5 μm thick superlattice structure is a factor of four higher than in highly n‐doped bulk material with comparable thickness without compromising too much the vertical conductivity as confirmed by two step TLM‐measurements. At 4K we could demonstrate an extremely high effective mobility of 18760 cm2/Vs at n=2×1014 cm–2 (R=1.6Ω/®), a clear verification of our excellent crystal quality. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effects of growth temperature on the crystallinity of GaN in gallium hydride vapor phase epitaxy method
Authors: Yamada Norihide , Imade Mamoru , Kitano Yoshihiro , Kawamura Fumio , Yoshimura Masashi , Kitaoka Yasuo , Sasaki Takatomo , Mori Yusuke
Published: April 2008

High temperature growth was investigated as a way of improving the crystallinity and surface morphology of the gallium hydride vapor phase epitaxy (GaH‐VPE) crystal growth method. In this method, gallium hydride (GaHx: x=1, 2, 3) is characteristically used as a Ga source to grow GaN crystals. We previously confirmed that the growth rate of GaN increased with GaHx supply and could attain almost the same rate as that of the hydride vapor phase epitaxy (HVPE) method. However, an improvement of the surface morphology and crystallinity of GaN crystals was required. In the present study, the dependence of growth temperature on the crystallinity and the surface morphology of grown crystals was investigated, resulting in both a flat surface and an improvement in crystallinity at temperatures higher than 1150 °C. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computer systems availability evaluation using a segregated failures model
Authors: Vilkomir Sergiy A. , Parnas David L. , Mendiratta Veena B. , Murphy Eamonn
Published: April 2008

This paper presents the segregated failures model (SFM) of availability of fault‐tolerant computer systems with several recovery procedures. This model is compared with a Markov chain model and its advantages are explained. The basic model is then extended for the situation when the coverage factor is unknown and the failure escalation rates must be used instead. A simple practical analytical approach to availability evaluation is provided and illustrated in detail by estimating the availability of two versions of a reliable clustered computing architecture. For these examples, numeric values of availability indexes are computed and the contribution of each recovery procedure to total system availability is analysed. Copyright © 2008 John Wiley & Sons, Ltd.