bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neue Biokatalysatoren für die Weiße Biotechnologie
Authors: Drepper T. , Eggert T. , Hummel W. , Leggewie C. , Pohl M. , Rosenau F. , Jaeger K.‐E. 
Published: March 2006

AbstractDie Weiße Biotechnologie verwendet Mikroorganismen und Enzyme, um chemische Produkte herzustellen. Daher nimmt der Bedarf an neuen Enzymen als Biokatalysatoren für die Biotechnologie‐Industrie stetig und schnell zu. Vorgestellt wird die Isolierung neuer Enzymgene, die Konstruktion von Expressionssystemen und Bakterienstämmen, aber auch die Optimierung bereits vorhandener Enzyme mit Methoden der gerichteten Evolution. Daneben werden biotechnologisch relevante Enzymklassen untersucht, die zur Darstellung enantiomerenreiner Verbindungen verwendet werden können.
Stable signal recovery from incomplete and inaccurate measurements
Authors: Candès Emmanuel J. , Romberg Justin K. , Tao Terence 
Published: March 2006

AbstractSuppose we wish to recover a vector x0 ∈ ℝ𝓂 (e.g., a digital signal or image) from incomplete and contaminated observations y = A x0 + e; A is an 𝓃 × 𝓂 matrix with far fewer rows than columns (𝓃 ≪ 𝓂) and e is an error term. Is it possible to recover x0 accurately based on the data y?To recover x0, we consider the solution x# to the 𝓁1‐regularization problem

where ϵ is the size of the error term e. We show that if A obeys a uniform uncertainty principle (with unit‐normed columns) and if the vector x0 is sufficiently sparse, then the solution is within the noise level

As a first example, suppose that A is a Gaussian random matrix; then stable recovery occurs for almost all such A's provided that the number of nonzeros of x0 is of about the same order as the number of observations. As a second instance, suppose one observes few Fourier samples of x0; then stable recovery occurs for almost any set of 𝓃 coefficients provided that the number of nonzeros is of the order of 𝓃/(log 𝓂)6.In the case where the error term vanishes, the recovery is of course exact, and this work actually provides novel insights into the exact recovery phenomenon discussed in earlier papers. The methodology also explains why one can also very nearly recover approximately sparse signals. © 2006 Wiley Periodicals, Inc.
Functional large deviations for burgers particle systems
Authors: Lifshits Mikhail A. , Shi Zhan 
Published: March 2006

AbstractWe consider Burgers particle systems, i.e., one‐dimensional systems of sticky particles with discrete white‐noise‐type initial data (not necessarily Gaussian), and describe functional large deviations for the state of the systems at any given time. For specific functionals such as maximal particle mass, particle speed, rarefaction interval, momentum, and energy, the research was initiated by Avellaneda and E [1, 2] and pursued further by Ryan [14]. Our results extend those of Ryan and contain many other examples. © 2006 Wiley Periodicals, Inc.
Fast‐scale bifurcation in single‐stage PFC power supplies operating with DCM boost stage and CCM forward stage
Authors: Wu Xiaoqun , Tse Chi K. , Wong Siu Chung , Lu Junan 
Published: March 2006

AbstractThis paper describes the fast‐scale bifurcation phenomena of a single‐stage single‐switch power‐factor‐correction (PFC) regulator comprising a boost stage operating in discontinuous conduction mode (DCM) and a forward stage operating in continuous conduction mode (CCM). The two stages combine into a single stage by sharing one main switch and one control loop. Using ‘exact’ cycle‐by‐cycle computer simulations, the effects of various circuit parameters on fast‐scale instabilities are studied. The results are qualitatively verified by experimental measurements. This work provides a clear picture of how the variation of certain practical parameters can render such a circuit fast‐scale unstable. Copyright © 2006 John Wiley & Sons, Ltd.
Iron(III) Complexes with the Ligand N′,N′‐Bis[(2‐pyridyl)methyl]ethylenediamine (uns‐penp) and Its Amide Derivative N‐Acetyl‐N′,N′‐bis[(2‐pyridyl)methyl]ethylenediamine (acetyl‐uns‐penp)
Authors: Xu Jing‐Yuan , Astner Jörg , Walter Olaf , Heinemann Frank W. , Schindler Siegfried , Merkel Michael , Krebs Bernt 
Published: March 2006

AbstractSynthesis and structural characterization of the iron(III) complexes of the tripodal ligands N′,N′‐bis[(2‐pyridyl)methyl]ethylenediamine (uns‐penp), [Fe(uns‐penp)Cl2]ClO4·CH3CN, [{Fe(uns‐penp)Cl}2O](ClO4)2·2CH3CN and the amide derivative N‐Acetyl‐N′,N′‐bis[(2‐pyridyl)methyl]ethylenediamine (acetyl‐uns‐penp), [Fe2(acetyl‐uns‐penp)2O](ClO4)2·H2O, [Fe(acetyl‐uns‐penp)(tcc)Br]·(C2H5)2O (tcc = tetrachlorocatecholate), and [{Fe(acetyl‐uns‐penp)(tcc)}2O]·(C2H5)2O·CH3OH are reported. Catechol dioxygenase reactivity of in situ prepared complex solutions was tested and showed that all complexes reacted slower compared with the iron tmpa system described in the literature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis of Novel α‐Aminoboronate Complexes of Aminoboranes and Aminocyanoboranes
Authors: Shibli Amal , Srebnik Morris 
Published: March 2006

AbstractTertiary amines activated either by borane (BH3) or cyanoborane (BH2CN) groups were α‐C lithiated with sBuLi (2 equiv.) and then treated with 2‐isopropoxy‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolane to produce the α‐aminoboronate complexes of aminoboranes and aminocyanoboranes 2–7 in 70–85 % yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Alteration in the Binding Property of a Laterally Nonsymmetric Aza Cryptand toward CuII, AgI, and TlIIons upon Derivatization with a Cyanomethyl Group
Authors: Ray Debdas , Bharadwaj Parimal K. 
Published: March 2006

AbstractThe laterally nonsymmetric aza cryptandLoreadily forms mononuclear inclusion complexes with metal ions like CuII, NiII, AgI, TlI, and so forth. However, when the secondary amines present in the three bridges are substituted by a cyanomethyl group to yield a new cryptandL, its metal‐binding properties are drastically altered. Thus, whileLobinds AgIat the tren end, showing AgN4coordination, inL, the bridgehead nitrogen atoms are pulled inside to form a two‐coordinate complex of AgIand none of the O or N atoms present in the three bridges are involved in coordination. This is probably the first example where the two bridgehead atoms are pulled inside to the maximum to bind the metal ion. Likewise, the TlIion shows TlN4coordination withLo, while inLit is loosely bound at the tren end, showing TlN3coordination. Upon treatment with a AgIsalt, the TlIcan be replaced almost instantaneously. On the other hand, with copper(II) tetrafluoroborate salt in moist DMF, two of the cyanide groups inLare converted to carboxylic acid groups and bind the metal ion from outside. The CuIIion in this complex shows distorted octahedral coordination where the two O atoms from the two carboxylic acid groups and the two corresponding N atoms in the two bridges are bound equatorially. The two axial sites are occupied by the nearby bridgehead N atom and the O atom of a DMF molecule. All five complexes and the free ligands are characterized by spectroscopic and X‐ray crystallographic studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Reactions of 13CO with Ethoxycarbonylcarbene‐Bridged Dicobalt Carbonyl Complexes: [μ2‐{Ethoxycarbonyl(methylene)}‐μ2‐(carbonyl)bis(tricarbonylcobalt)(Co–Co)] and [Di‐μ2‐{ethoxycarbonyl(methylene)}bis(tricarbonylcobalt)(Co–Co)]
Authors: Fördős Eszter , Ungvári Neszta , Kégl Tamás , Ungváry Ferenc 
Published: March 2006

AbstractIn a CH2Cl2 solution, under an atmospheric pressure of 13CO, the bridging and terminal CO ligands of the cobalt complex[μ2‐{ethoxycarbonyl(methylene)}‐μ2‐(carbonyl)bis(tricarbonylcobalt)(Co–Co)] (1) exchange with external 13CO at the same rate. The overall rate of CO exchange is kobs (10 °C) = 9.4 × 10–3 s–1 and kobs (25 °C) = (20.1 ± 1.2)  × 10–3 s–1. In the presence of excess ethanol diethyl malonate (DEM), EtO213CCH2CO2Et is formed from 1 at a much smaller rate [kDEM (10 °C) = 0.40 × 10–5 s–1 and kDEM (25 °C) = (1.2 ± 0.1) × 10–5 s–1]. On the other hand, the complex [di‐μ2‐{ethoxycarbonyl(methylene)}bis(tricarbonylcobalt)(Co–Co)](2) does not exchange its CO ligands for 13CO at all at 10 or 25 °C. In the presence of excess ethanol, diethyl malonate with natural isotopic distribution, and 13CO, ligands containing complex 1 are formed simultaneously and at the same rate, which is kobs (10 °C) = (15.2 ± 1.1) × 10–5 s–1 and kobs (25 °C) = (33.5 ± 1.8) × 10–5 s–1. Variable temperature 13C NMR spectra of 1 and 2 reveal fluxional behavior for both complexes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A comparison between two receptor models to determine the source apportionment of atmospheric pollutants
Authors: Caselli Maurizio , de Gennaro Gianluigi , Ielpo Pierina 
Published: March 2006

AbstractTwo frequently used factor analysis (FA) methods, Absolute Principal Components Scores (APCS) and Target Transformation Factor Analysis (TTFA), are compared by examining two cases with different complexity on sources and parameters. The effect of the noise contribution on the data is evaluated.By applying the methods to simulated data matrices, it has been found that the APCS method characterizes the source matrix better than TTFA method. APCS method also reconstructs the sample better than TTFA. In addition both methods are applied to real data collected during a monitoring campaign in Taranto city (South Italy). Copyright © 2006 John Wiley & Sons, Ltd.
Soil losses due to potato and sugar beet harvesting in NE China
Authors: Li Y. , Ruysschaert G. , Poesen J. , Zhang Q. W. , Bai L. Y. , Li L. , Sun L. F. 
Published: March 2006

AbstractThe study of soil loss due to crop harvesting (SLCH) started only recently in soil erosion research. It describes the mass of adhering soil, soil clods and rock fragments that is lost from arable land during the harvesting of crops such as potato, sugar beet, sweet potato and cassava. Some research on mechanized agriculture in Europe revealed that soil loss rates due to crop harvesting can be comparable to water and tillage erosion rates. However, little is known about soil losses caused by manually harvested crops in other parts of the world. This study investigated SLCH for potato and sugar beet plots on farmer's fields spread over four regions in northeast China where harvesting is carried out by hand. Soil losses for sugar beet were on average 1·0 Mg/ha/harvest, ranging from 0·2 to 1·9 Mg/ha/harvest, and SLCH for potato ranged from 0·2 to 3·0 Mg/ha/harvest with an average of 1·2 Mg/ha/harvest. Soil moisture content, average root mass and plant density could explain 45 to 67 per cent of the variability of SLCH for sugar beet. The effect of soil texture was the opposite to findings of other studies, which could be attributed to the strong correlations among the variables and to the effect of the harvesting operator. SLCH variability for potatoes could best be explained by soil texture. SLCH for sugar beet was much lower than European SLCH values for this crop, which can be explained by differences in harvesting technique and agronomic practices. SLCH for potato was comparable to soil losses measured in Belgium, especially if clods are removed on the harvesting machine. However, clay contents of the soils were larger in this study and soil losses were lower than in Belgium for comparable clay contents. Although SLCH is not the dominant soil erosion process in NE China, it contributes to overall soil loss rates, which have already exceeded their critical tolerance limits in this region. Copyright © 2006 John Wiley & Sons, Ltd.
Predicting catchment sediment yield in Mediterranean environments: the importance of sediment sources and connectivity in Italian drainage basins
Authors: de Vente Joris , Poesen Jean , Bazzoffi Paolo , Rompaey Anton Van , Verstraeten Gert 
Published: March 2006

AbstractPredicting sediment yield at the catchment scale is one of the main challenges in geomorphologic research. The application of both physics‐based models and regression models has until now not provided very satisfying results for prediction of sediment yield for medium to large sized catchments (c. >50 km2). The explanation for this lies in a combination of the large data requirements of most models and a lack of knowledge to describe all processes and process interactions at the catchment scale. In particular, point sources of sediment (e.g. gullies, mass movements), connectivity and sediment transport remain difficult to describe in most models. From reservoir sedimentation data of 44 Italian catchments, it appeared that there was a (non‐significant) positive relation between catchment area and sediment yield. This is in contrast to what is generally expected from the theory of decreasing sediment delivery rates with increasing catchment area. Furthermore, this positive relation suggests that processes other than upland erosion are responsible for catchment sediment yield. Here we explore the potential of the Factorial Scoring Model (FSM) and the Pacific Southwest Interagency Committee (PSIAC) model to predict sediment yield, and indicate the most important sediment sources. In these models different factors are used to characterize a drainage basin in terms of sensitivity to erosion and connectivity. In both models an index is calculated that is related to sediment yield. The FSM explained between 36 and 61 per cent of the variation in sediment yield, and the PSIAC model between 57 and 62 per cent, depending on the factors used to characterize the catchments. The FSM model performed best based on a factor to describe gullies, lithology, landslides, catchment shape and vegetation. Topography and catchment area did not explain additional variance. In particular, the addition of the landslide factor resulted in a significantly increased model performance. The FSM and PSIAC model both performed better than a spatially distributed model describing water erosion and sediment transport, which was applied to the same catchments but explained only between 20 and 51 per cent of the variation in sediment yield. Model results confirmed the hypothesis that processes other than upland erosion are probably responsible for sediment yield in the Italian catchments. A promising future development of the models is by the use of detailed spatially distributed data to determine the scores, decrease model subjectivity and provide spatially distributed output. Copyright © 2006 John Wiley & Sons, Ltd.
Consequences of hyperconcentrated flow for process‐based soil erosion modelling on the Chinese Loess Plateau
Authors: Hessel Rudi 
Published: March 2006

AbstractHigh sediment concentrations in runoff are a characteristic feature of the Chinese Loess Plateau, and are probably caused by factors such as the occurrence of erodible materials on steep slopes, the characteristics of the loess and the harsh climate that results in low plant cover. When sediment concentration increases, fluid density increases, viscosity increases and settling velocity decreases. These effects become increasingly important with increasing concentration and can result in flow behaviour that is quite different from that of clear water flow. Although the net effect of these changes on the flow is not always apparent, erosion models that deal with high sediment concentrations should consider such effects and could include corrections for some of these effects. A case study in a small catchment on the Loess Plateau indicated that sediment concentrations were considerable, and literature data suggested that for such sediment concentrations, corrections for settling velocity, fluid density and viscosity are needed. Furthermore, a number of corrections are necessary to be able to compare field measurements with results of soil erosion models: sediment volume should be subtracted from runoff volume and a density correction is needed to use data from a pressure transducer. For flumes that were used to measure discharge from smaller areas inside the catchment, the measured water level should be corrected by subtracting the sediment level in the flume from the water level, while the sediment volume should also be subtracted from the discharge. Finally, measured concentration should be corrected to give concentration expressed as grams per litre of clear water, since soil erosion models express sediment concentration in this way. Copyright © 2006 John Wiley & Sons, Ltd.
Differential priming effects of color‐opponent subliminal stimulation on visual magnetic responses
Authors: Hoshiyama Minoru , Kakigi Ryusuke , Takeshima Yasuyuki , Miki Kensaku , Watanabe Shoko 
Published: March 2006

AbstractWe investigated the effects of subliminal stimulation on visible stimulation to demonstrate the priority of facial discrimination processing, using a unique, indiscernible, color‐opponent subliminal (COS) stimulation. We recorded event‐related magnetic cortical fields (ERF) by magnetoencephalography (MEG) after the presentation of a face or flower stimulus with COS conditioning using a face, flower, random pattern, and blank. The COS stimulation enhanced the response to visible stimulation when the figure in the COS stimulation was identical to the target visible stimulus, but more so for the face than for the flower stimulus. The ERF component modulated by the COS stimulation was estimated to be located in the ventral temporal cortex. We speculated that the enhancement was caused by an interaction of the responses after subthreshold stimulation by the COS stimulation and the suprathreshold stimulation after target stimulation, such as in the processing for categorization or discrimination. We also speculated that the face was processed with priority at the level of the ventral temporal cortex during visual processing outside of consciousness. Hum Brain Mapp, 2006. © 2006 Wiley‐Liss, Inc.
Cooperativity between Rad51 and C/EBP family transcription factors modulates basal and Tat‐induced activation of the HIV‐1 LTR in astrocytes
Authors: Chipitsyna Galina , Sawaya Bassel E. , Khalili Kamel , Amini Shohreh 
Published: March 2006

AbstractTranscription of the HIV‐1 genome is a complex event that requires functional and physical communication of cellular proteins that recognize the LTR sequence with viral proteins, most notably, Tat. Moreover, studies have revealed the ability of Tat to induce transcription of a variety of cellular genes whose products can affect the status of cells, thus contributing to the pathogenesis of AIDS. Recently, we demonstrated that expression of Tat in astrocytes and other neural cells leads to upregulation of Rad51, a major component of DNA repair via homologous recombination. The unscheduled upregulation of Rad51, in turn, has an impact upon the extent of chromosomal abnormalities that are seen in Tat‐producing cells. Here, we asked whether an elevation in Rad51 levels influences the extent of viral gene transcription in astrocytic cells. Our results demonstrate that ectopic expression of Rad51 enhances the basal‐ and the Tat‐induced transcription of the LTR promoter. This event requires cooperativity from the C/EBP family of transcription factors including C/EBPβ and C/EBPβ homologous protein (CHOP). Similar to Tat, we showed that Rad51 interacts with C/EBPβ and augments its interaction with the DNA motif spanning nucleotides −120 to −94 of the LTR. Interestingly, Tat exhibited the capacity to augment the synergism between Rad51 and C/EBPβ. Our results also demonstrate that the level of activation of the LTR by CHOP and Tat, either alone or together, is elevated in the presence of the SW1/SNF1 chromatin remodeling complex. These observations unravel a new pathway for Tat activation of the LTR that includes the positive feedback loop involving Rad51 and C/EBPβ family proteins. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
Subcutaneous tissue fibroblast cytoskeletal remodeling induced by acupuncture: Evidence for a mechanotransduction‐based mechanism
Authors: Langevin Helene M. , Bouffard Nicole A. , Badger Gary J. , Churchill David L. , Howe Alan K. 
Published: March 2006

AbstractAcupuncture needle rotation has been previously shown to cause specific mechanical stimulation of subcutaneous connective tissue. This study uses acupuncture to investigate the role of mechanotransduction‐based mechanisms in mechanically‐induced cytoskeletal remodeling. The effect of acupuncture needle rotation was quantified by morphometric analysis of mouse tissue explants imaged with confocal microscopy. Needle rotation induced extensive fibroblast spreading and lamellipodia formation within 30 min, measurable as an increased in cell body cross sectional area. The effect of rotation peaked with two needle revolutions and decreased with further increases in rotation. Significant effects of rotation were present throughout the tissue, indicating the presence of a response extending laterally over several centimeters. The effect of rotation with two needle revolutions was prevented by pharmacological inhibitors of actomyosin contractility (blebbistatin), Rho kinase (Y‐27632 and H‐1152), and Rac signaling. The active cytoskeletal response of fibroblasts demonstrated in this study constitutes an important step in understanding cellular mechanotransduction responses to externally applied mechanical stimuli in whole tissue, and supports a previously proposed model for the mechanism of acupuncture involving connective tissue mechanotransduction. J. Cell. Physiol. © 2006 Wiley‐Liss, Inc.
Transforming growth factor β2 autocrinally mediates neuronal cell death induced by amyloid‐β
Authors: Hashimoto Yuichi , Nawa Mikiro , Chiba Tomohiro , Aiso Sadakazu , Nishimoto Ikuo , Matsuoka Masaaki 
Published: March 2006

AbstractAmyloid β (Aβ), the major component of the senile plaques of Alzheimer's disease, is implicated in neuronal cell death. We have found that Aβ42, a neurotoxic form of Aβ peptide, induces both neuronal and glial expression of TGFβ2. We have further demonstrated that the addition into culture media of neutralizing antibody to TGFβ2 or a large amount of the recombinant soluble amyloid precursor protein α, the extracellular domain of amyloid precursor protein (APP) generated by α secretase, suppresses death in primary cortical neurons (PCNs) induced by Aβ42 in vitro. Combined with the finding in our recent study indicating that TGFβ2 is a neuronal cell death‐inducing ligand for APP, it is suggested that TGFβ2 is an autocrinal mediator for Aβ42‐induced death in PCNs. © 2006 Wiley‐Liss, Inc.
Beacon immunoreactivity in the rat hypothalamus
Authors: Ng Y.K. , Brailoiu G.C. , Dun S.L. , Ling E.A. , Yang J. , Chang J.K. , Dun N.J. 
Published: March 2006

AbstractBeacon (BC) is a peptide of 73 amino acids, whose gene expression was first reported in the hypothalamus of Psammomys obesus (or Israeli sand rat). To appreciate better the functional role of BC in normal rats and sand rats, the distribution of BC immunoreactivity (irBC) and its subcellular localization were studied in the brain of Sprague‐Dawley rats. In the hypothalamus, intense staining was present in neurons of the supraoptic (SO), paraventricular (PVH), and accessory neurosecretory nuclei and in cell processes of median eminence. Double labeling of the hypothalamic sections with mouse monoclonal oxytocin (OT) antibody and rabbit polyclonal BC antiserum revealed that nearly all OT‐immunoreactive cells from SO, PVH, and accessory neurosecretory nuclei were irBC. Double labeling of the sections with guinea pig vasopressin (VP) antiserum and BC antiserum showed that a population of VP‐immunoreactive neurons was irBC. By immunoelectron microscopy, immunoreactive product was associated with mitochondrial membranes or appeared as electron‐dense bodies in many PVH and SO neurons. Most of the neurosecretory granules were unstained for BC. Taken together, our results indicate the presence of beacon in the OT‐containing neurons and a population of VP‐containing neurons, mostly associated with mithocondrial membrane. Insofar as the amino acids sequence of beacon is identical to that of ubiquitin‐like 5, it is possible that the distribution of BC immunoreactivity noted in our study is that of ubiquitin‐like 5 peptide in the rat hypothalamus. © 2006 Wiley‐Liss, Inc.