bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single and Double CCl‐Activation of Methylene Chloride by P,N‐ligand Coordinated Rhodium Complexes
Authors: Blank Benoît , Glatz Germund , Kempe Rhett 
Published: December 2008

AbstractTwo in one: The simultaneous formation of bimetallic μ‐methylene bridged RhIII complexes as well as dimeric RhIII complexes with terminal chloromethyl groups is observed for P,N‐ligand stabilized RhI complexes by CCl bond activation of methylene chloride. A mechanistic proposal for the formation of both activation products is also discussed.magnified imageThe synthesis of RhI complexes with P‐functionalized aminopyridine ligands is reported as well as the first simultaneous observation of a single and double activation of CCl bonds of methylene chloride affording both a dimeric RhIII complex bearing terminal CH2Cl groups in addition to a binuclear RhIII complex with a bridging μ‐CH2 group. The structures of the oxidative addition products were obtained by X‐ray diffraction studies and NMR experiments were performed to elucidate some aspects of the reaction pathway.
Magneto‐Structural Correlations in a 1,3,2‐Dithiazolyl Radical Crystal, BBDTA⋅GaBr4: Structure and Magnetic Properties of its Three Polymorphs
Authors: Fujita Wataru , Kikuchi Koichi 
Published: December 2008

AbstractThree attractions in one cage: Various magnetic networks are formed in the three polymorphs of an organic magnet, BBTDA(=benzo[1,2‐d:4,5‐d′]bis[1,3,2]dithiazole)⋅GaBr4. The three phases show quite different magnetic behaviors in spite of having the same chemical formula. Their magnetic differences originate from the relative configuration of the neighboring organic radical molecules in their crystals.magnified imageWe investigate the preparation, crystal growth, crystal structure, and magnetic properties of the three polymorphs (α, β, and γ) of an organic magnet, BBDTA(=benzo[1,2‐d:4,5‐d′] bis[1,3,2]dithiazole)⋅GaBr4, which is an S‐1/2 system. In the α phase, BBDTA+ units form a square‐planar lattice, and show canted antiferromagnetism with a magnetic coupling constant J/kB of −18 K and a canting angle of 0.15° below 15.5 K. The β phase is composed of a ferromagnetic regular chain with a J/kB value of +4.5 K and a strong antiferromagnetic chain with J/kB=−99 K, and shows ferromagnetic ordering in spins of purely the ferromagnetic chain below 0.4 K. The γ phase is isostructural with γ‐BBDTA⋅GaCl4, which is an organic ferromagnet below 7.0 K, and possesses antiferromagnetic interactions of J/kB=−60 K between BBDTA+ cations, and shows no magnetic ordering until 2 K. The magnetic properties of these phases are quite sensitive to the molecular alignment in the crystals.
Point and Interval Estimation of the Population Size Using a Zero‐Truncated Negative Binomial Regression Model
Authors: Cruyff Maarten J. L. F. , van der Heijden Peter G. M. 
Published: December 2008

AbstractThis paper presents the zero‐truncated negative binomial regression model to estimate the population size in the presence of a single registration file. The model is an alternative to the zero‐truncated Poisson regression model and it may be useful if the data are overdispersed due to unobserved heterogeneity. Horvitz–Thompson point and interval estimates for the population size are derived, and the performance of these estimators is evaluated in a simulation study. To illustrate the model, the size of the population of opiate users in the city of Rotterdam is estimated. In comparison to the Poisson model, the zero‐truncated negative binomial regression model fits these data better and yields a substantially higher population size estimate. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Comparison of Population Size Estimators under the Truncated Count Model With and Without Allowance for Contaminations
Authors: Viwatwongkasem Chukiat , Kuhnert Ronny , Satitvipawee Pratana 
Published: December 2008

AbstractThe purpose of the study is to estimate the population size under a homogeneous truncated count model and under model contaminations via the Horvitz‐Thompson approach on the basis of a count capture‐recapture experiment. The proposed estimator is based on a mixture of zero‐truncated Poisson distributions. The benefit of using the proposed model is statistical inference of the long‐tailed or skewed distributions and the concavity of the likelihood function with strong results available on the nonparametric maximum likelihood estimator (NPMLE). The results of comparisons, for finding the appropriate estimator among McKendrick's, Mantel‐Haenszel's, Zelterman's, Chao's, the maximum likelihood, and the proposed methods in a simulation study, reveal that under model contaminations the proposed estimator provides the best choice according to its smallest bias and smallest mean square error for a situation of sufficiently large population sizes and the further results show that the proposed estimator performs well even for a homogeneous situation. The empirical examples, containing the cholera epidemic in India based on homogeneity and the heroin user data in Bangkok 2002 based on heterogeneity, are fitted with an excellent goodness‐of‐fit of the models and the confidence interval estimations may also be of considerable interest. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the role of protein structural dynamics in the catalytic activity and thermostability of serine protease subtilisin Carlsberg
Authors: Pagán Miraida , Solá Ricardo J. , Griebenow Kai 
Published: December 2008

AbstractThe effect of structural dynamics on enzyme activity and thermostability has thus far only been investigated in detail for the serine protease α‐chymotrypsin (for a recent review see Solá et al., Cell Mol Life Sci 2007, 64(16): 2133–2152). Herein, we extend this type of study to a structurally unrelated serine protease, specifically, subtilisin Carlsberg. The protease was incrementally glycosylated with chemically activated lactose to obtain various subtilisin glycoconjugates which were biophysically characterized. Near UV‐CD spectroscopy revealed that the tertiary structure was unaffected by the glycosylation procedure. H/D exchange FT‐IR spectroscopy was performed to assess the changes in structural dynamics of the enzyme. It was found that increasing the level of glycosylation caused a linearly dependent reduction in structural dynamics. This led to an increase in thermostability and a decrease in the catalytic turnover rate for both, the enzyme acylation and deacylation steps. These results highlight the possibility that a structural dynamics—activity relationship might be a phenomenon generally found in serine proteases. Biotechnol. Bioeng. 2009;103: 77–84. © 2008 Wiley Periodicals, Inc.
Biofilm monitoring on rotating discs by image analysis
Authors: Pons Marie‐Noëlle , Milferstedt Kim , Morgenroth Eberhard 
Published: December 2008

AbstractThe macrostructure development of biofilms grown in a lab‐scale rotating biological contactor was monitored by analyzing the average opacity and the texture of gray‐level images of the discs. The reactor was fed with municipal or synthetic wastewater. Experiments lasted on average 4–14 weeks. The images were obtained with a flat‐bed scanner. The opacity and its standard deviation are directly extracted from the annular zone where the biofilm develops. This zone is defined by the outer edge of the disc and the waterline. The spatial gray‐level dependence matrix (SGLDM) approach was used for the texture assessment. As this method requires rectangular images, a geometrical transformation had to be developed to transform the ring into a workable area. This transformation now allows quantitative image analysis on circular biofilms. As a last step, Principal Components Analysis was applied to the set of textural descriptors to reduce the number of textural parameters. Opacity and textural information allowed the non‐intrusive monitoring of the growth/regrowth of the biofilms as well as biofilm loss, due to detachment, auto‐digestion, or protozoan grazing. Textural description was very valuable by helping to discriminate biofilms of similar opacity characteristics but presenting different macrostructures. Biotechnol. Bioeng. 2009;103: 105–116. © 2008 Wiley Periodicals, Inc.
Modern cross‐linking strategies for synthesizing acellular hemoglobin‐based oxygen carriers
Authors: Harris David Raphael , Palmer Andre Francis 
Published: December 2008

AbstractUnmodified cell‐free hemoglobin (Hb) is structurally unstable when transfused into the blood stream (Valeri et al., Artif Cells Blood Substit Immobil Biotechnol. 2000;28:451‐475; Chan et al., Toxicol Pathol. 2000;28:635‐642; Eike, Dissertation, 2005; Eike and Palmer, Biotechnol Prog. 2004;20:946‐952). This review examines some of the latest chemical strategies used over the last 5 years to intra‐ and intermolecularly cross‐link Hb, thereby stabilizing its quaternary structure. Therefore, this work will address the following aspects: (1) site‐specific chemical modifications of Hb and (2) non‐site‐specific chemical modifications of Hb, including, but not limited to, PolyHeme®, Hemopure®, Oxyglobin®, and SOD‐Hb. Current strategies for synthesizing PEGylated Hb is outside the scope of this review and will not be discussed herein. For a more thorough review of PEGylated Hb, the reader is directed to the following works: Cabrales and Friedman, Transfus Alternatives in Transfus Med. 2007;9:281–293 and Winslow, Biochim Biophys Acta, 2008;1784(10):1382–1386.
Surface‐Induced Regulation of Podosome Organization and Dynamics in Cultured Osteoclasts
Authors: Geblinger Dafna , Geiger Benjamin , Addadi Lia 
Published: December 2008

AbstractBone is continuously repaired and remodeled through the well‐coordinated activity of osteoblasts, which form new bone, and osteoclasts, which resorb it. How osteoclasts sense the properties of the bone surface remains unclear. By combining light and electron microscopy, we compared osteoclast behavior on three distinct surfaces: glass, calcite single crystals, and bone. Podosomes, the basic units of the adhesion structure, and their organization into superstructures were found to be common to cells that were attached to all three substrates, whereas the structure of the resorption organelle, the so‐called “ruffled border,” markedly differed. Moreover, the integrity, stability, and dynamic behavior of the adhesion superstructures also fundamentally differed, depending on the substrate. We conclude that osteoclasts sense the local properties of the underlying substrate and respond to these signals, both locally and globally.
Utilization of Evaporation during the Crystallization Process: Self‐Templation of Organic Parallelogrammatic Pipes
Authors: Seo Myungeun , Kim Jung Hak , Seo Gon , Shin Chae‐Ho , Kim Sang Youl 
Published: December 2008

AbstractAnalogues of 4‐dodecyloxy‐2‐trifluoromethylbenzamide (12FH2) consisting of a hydrophobic alkyl chain, a trifluoromethylated aromatic ring, and a self‐complementary hydrogen‐bonding amido group were synthesized, and the structural effect of each component on the formation of parallelogrammatic pipes was investigated. Differential scanning calorimetry and powder XRD analyses revealed that all‐trans L and gauche‐rich S polymorphic forms appeared for the analogues with more than eight carbon atoms in the alkyl chain, that is, the polymorphism originates in the conformation of the alkyl groups and hydrogen‐bonding patterns of the benzamide group. Also, the trifluoromethyl substituent is crucial in that it provides an appropriate molecular balance between the benzamide and alkyl groups. Scanning electron microscopy and powder XRD analyses of solids obtained by a drying‐mediated assembly process revealed that production of the L polymorph by polymorphic transition from the S polymorph resulted in evolution of a three‐dimensional structure when the alkyl group has more than 12 carbon atoms. Among the series of compounds, 12FH2 and 4‐tetradecyloxy‐2‐trifluoromethylbenzamide (14FH2) formed parallelogrammatic pipes with micrometer dimensions. An atomic force microscopy study of 12FH2 suggested that a single pipe may be composed of platelike crystallites of L polymorph. From a mercury‐intrusion porosimetry study, it was determined that macroporous materials with average pore diameters of about 40 μm and porosity of about 80 % were obtained. The previously proposed self‐templation mechanism by polymorphic transition from S to L polymorph was further discussed in view of polymorphism and the crystallization rate. An appropriate molecular balance between the benzamide and alkyl groups is necessary to induce a proper polymorphic transition for the development of a three‐dimensional hollow structure in the evaporation process.
Photochemical Regulation of an Artificial Hydrolase by a Backbone Incorporated Tertiary Structure Switch
Authors: Lindgren N. Johan V. , Varedian Miranda , Gogoll Adolf 
Published: December 2008

AbstractA stilbene chromophore has been incorporated into the turn region of a 42 amino acid peptide, linking two helical peptide sections. Spatial proximity between these sections, as well as aggregation into dimers, is required to facilitate the catalytic function of this artificial hydrolase. Photomodulation of the hydrolase activity results in an increase of the activity of 42 % upon switching from the trans to the cis isomer of the chromophore. This is rationalized by a change in the aggregation state of the peptidomimetic, which is supported by diffusion coefficients obtained from PFG‐NMR experiments. The results show that incorporation of a small, relatively flexible chromophore into a large peptide is capable of inducing a considerable change in tertiary structure and thus, functionality.
Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings
Authors: Fernández Rafael , Grirrane Abdessamad , Resa Irene , Rodríguez Amor , Carmona Ernesto , Álvarez Eleuterio , Gutiérrez‐Puebla Enrique , Monge Ángeles , López del Amo Juan Miguel , Limbach Hans‐Heinrich , Lledós Agustí , Maseras Feliu , del Río Diego 
Published: December 2008

AbstractNew zincocenes [ZnCp′2] (2–5) with substituted cyclopentadienyl ligands C5Me4H, C5Me4tBu, C5Me4SiMe2tBu and C5Me4SiMe3, respectively, have been prepared by the reaction of ZnCl2 with the appropriate Cp′‐transfer reagent. For a comparative structural study, the known [Zn(C5H4SiMe3)2] (1), has also been investigated, along with the mixed‐ring zincocenes [Zn(C5Me5)(C5Me4SiMe3)] (6) and [Zn(C5Me5)(C5H4SiMe3)] (7), the last two obtained by conproportionation of [Zn(C5Me5)2] with 5 or 1, as appropriate. All new compounds were characterised by NMR spectroscopy, and by X‐ray methods, with the exception of 7, which yields a side‐product (C) upon attempted crystallisation. Compounds 5 and 6 were also investigated by 13C CPMAS NMR spectroscopy. Zincocenes 1 and 2 have infinite chain structures with bridging Cp′ ligands, while 3 and 4 exhibit slipped‐sandwich geometries. Compounds 5 and 6 have rigid, η5/η1(σ) structures, in which the monohapto C5Me4SiMe3 ligand is bound to zinc through the silyl‐bearing carbon atom, forming a ZnC bond of comparable strength to the ZnMe bond in ZnMe2. Zincocene 5 has dynamic behaviour in solution, but a rigid η5/η1(σ) structure in the solid state, as revealed by 13C CPMAS NMR studies, whereas for 6 the different nature of the Cp′ ligands and of the ring substituents of the η1‐Cp′ group (Me and SiMe3) have permitted observation for the first time of the rigid η5/η1 solution structure. Iminoacyl compounds of composition [Zn(η5‐C5Me4R)(η1‐C(NXyl)C5Me4R)] resulting from the reactions of some of the above zincocenes and CNXyl (Xyl=2,6‐dimethylphenylisocyanide) have also been obtained and characterised.
Grün fluoreszierendes Protein: unschätzbares Werkzeug der Zellforscher
Authors: Welter Kira 
Published: December 2008

AbstractDie Verwendung fluoreszierender Proteine zur Untersuchung von chemischen Prozessen in lebenden Zellen ist heute eine Standardmethode in der Biologie und der medizinischen Forschung. Damit können Wissenschaftler neue Einblicke in die molekularen Dimensionen des Lebens gewinnen und Prozesse wie etwa die Ausbreitung von Krebszellen oder die Arbeitsweise von Nervenzellen im Gehirn in Echtzeit untersuchen. Das grün fluoreszierende Protein (GFP) hat bei der Entwicklung dieser wertvollen Technik eine Pionierrolle gespielt. Für die Entdeckung und Weiterentwicklung des GFP teilen sich in diesem Jahr der Japaner Osamu Shimomura und die beiden US‐Amerikaner Martin Chalfie und Roger Y. Tsien den Nobelpreis für Chemie.
A simple PWM method for improving lamp current crest factor of valley‐filled electronic ballast
Authors: Lee Zhi‐Ren , Hsiao Horng‐Ching 
Published: December 2008

AbstractIn this paper, a PWM method to improve the lamp current crest factor (CCF) of the valley‐filled electronic ballast (VFEB) is presented. The VFEB has merits of high power factor, simple structure, and low cost. However, it results in an excessive CCF, which will shorten the lifetime of low‐pressure discharge lamp. The proposed method controls switching duty ratio by feeding forward the dc‐link voltage waveform of VFEB. It decreased the duty ratio with rising of dc‐link voltage. Therefore, the proposed method could restrain the lamp peak current and improve the lamp CCF. The control block diagram and basic theory are introduced to improve the CCF. The computer simulations verify the proposed method and derive a minimum lamp CCF. The experimental results demonstrate that the lamp CCF was reduced from 1.9 to 1.58, the ac line power factor is 96%, and the input current THD is 29.3%. The fixed switching frequency operation gains a satisfactory power quality. Copyright © 2008 John Wiley & Sons, Ltd.
Serum homocysteine, folate, vitamin B12 levels and arterial stiffness in diabetic patients: which of them is really important in atherogenesis?
Authors: Shargorodsky M. , Boaz M. , Pasternak S. , Hanah R. , Matas Z. , Fux A. , Beigel Y. , Mashavi M. 
Published: December 2008

AbstractAimHyperhomocystinaemia is associated with macro‐ and microangiopathic diabetic complications. However, the role of homocysteine (Hcy), serum folate, and vitamin B12 level in the development of premature vascular damage in type 2 diabetic patients is not clear. The present study was designed to assess the relationship between total Hcy, folate, and vitamin B12 levels and arterial stiffness, an early marker of generalized atherosclerosis.MethodsAs many as 86 subjects with type 2 diabetes mellitus were studied. All participants were evaluated for glucose, HbA1C, lipid profile, hs‐CRP, endothelin, Hcy, vitamin B12, and folate. Pulse wave velocity (PWV) and augmentation index (AI) were performed as a non‐invasive recording and computer analysis of the two artery sites pressure waveform using SphygmoCor (version 7.1, AtCor Medical, Sydney, Australia).ResultsHcy was significantly positively associated with age, serum creatinine, and vitamin B12 levels. No association between Hcy and folate was observed. The Hcy concentration was significantly positively associated with PWV (r = 0.540, p < 0.0001) and AI (r = 0.390, p < 0.0001). In a general linear model of PWV, Hcy emerged as an independent predictor of PWV even after controlling for age, creatinine, vitamin B12, and folate levels. In a multiple linear regression analysis, the association between Hcy and arterial stiffness was independent of traditional cardiovascular risk factors. Vitamin B12 levels were significantly inversely associated with tHcy (r = − 0.263, p = 0.015) and marginally associated with PWV(r = − 0.212, p = 0.052). Significant associations between folate levels and PWV were not detected.ConclusionsThe results lend support to the hypothesis that elevated Hcy may have a key role in the development of atherogenesis in diabetic patients. Additionally, vitamin B12 is significantly associated with tHcy concentrations and is identified as a marginally independent correlate of PWV in diabetic patients in the absence of folate deficiency. Copyright © 2008 John Wiley & Sons, Ltd.
Proneural gene ash1 promotes amacrine cell production in the chick retina
Authors: Mao Weiming , Yan Run‐Tao , Wang Shu‐Zhen 
Published: December 2008

AbstractThe diverse types of neurons and Müller glia in the vertebrate retina are believed to arise from common progenitor cells. To better understand how neural diversity is achieved during retinal neurogenesis, we examined the function of ash1, a proneural bHLH gene expressed in progenitor cells throughout retinal neurogenesis. Published studies using retinal explant culture derived from knockout mice concluded that ash1 is required for the production of late‐born neurons, including bipolar cells. In this study, gain‐of‐function experiments were carried out in ovo in embryonic chick retina. In the developing chick retina, expression of ash1 temporally overlapped with, but spatially differed from, the expression of ngn2, also a proneural gene expressed in progenitor cells throughout retinal neurogenesis. Retrovirus‐driven overexpression of ash1 in the developing chick retina decreased the progenitor population (BrdU+ or expressing ngn2), expanded the amacrine population (AP2α+ or Pax6+), and reduced bipolar (chx10 mRNA+) and Müller glial (vimentin+) populations. Photoreceptor deficiency occurred after the completion of neurogenesis. The number of ganglion cells, which are born first during retinal neurogenesis, remained unchanged. Similar overexpression of ngn2 did not produce discernible changes in retinal neurogenesis, nor in ash1 expression. These results suggest that ash1 promotes the production of amacrine cells and thus may participate in a regulatory network governing neural diversity in the chick retina. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2009
Image contrast enhancement based on differential gray level of gradient pixel pairs
Authors: Saitoh Fumihiko 
Published: December 2008

AbstractThis paper proposes a method for image contrast enhancement by using not only the distribution of gray levels but also the spatial features included in an objective input image. A contour appears on the boundary between two planes that have different gray levels. For image contrast enhancement, expanding the difference of the gray levels in the planes located on both sides of the contour is assumed to be effective. By expanding the subtraction between the gray levels in the neighboring planes, the contour becomes visually conspicuous. Therefore, the difference between the gray levels of the pixel pair is treated as the weight for contrast enhancement in the proposed method. The resultant images obtained by the proposed method had better contrast and less noise than those obtained by the conventional methods. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(7): 1–9, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10014
Ultrasonic diagnosis of cirrhosis based on preprocessing using pyramid recurrent neural network
Authors: Lu Jianming , Liu Jiang , Zhao Xueqin , Yahagi Takashi 
Published: December 2008

AbstractIn this paper, a pyramid recurrent neural network is applied to characterize the hepatic parenchymal diseases in ultrasonic B‐scan texture. The cirrhotic parenchymal diseases are classified into four types according to the size of hypoechoic nodular lesions. The B‐mode patterns are wavelet transformed, and then the compressed data are fed into a pyramid neural network to diagnose the type of cirrhotic diseases. Compared with the three‐layer neural networks, the performance of the proposed pyramid recurrent neural network is improved by a more efficient utilization of lower layers. Simulation results show that the proposed system is suitable for diagnosis of cirrhosis diseases. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(7): 10–19, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10121