bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamische Untersuchungen zum Aminosäure‐Stoffwechsel von Bacillus megaterium mittels stabiler Isotope
Authors: Fürch T. , Hollmann R. , Wang W. , Wittmann C. , Deckwer W.‐D.
Published: March 2006

Neuere Untersuchungen haben gezeigt, dass Bacillus megaterium auch als Produktionsstamm bei der Expression von Fremd‐Genen vorteilhaft eingesetzt werden kann. Gegenstand dieses Beitrags sind Ergebnisse aus dynamischen Untersuchungen des Aminosäure‐Stoffwechsels von Bacillus megaterium. Vorgestellt wird eine dynamische Methode zur Markierung mit stabilen Isotopen (13C). Damit ist es möglich, kinetische Informationen über die Biosynthese von proteinogenen Aminosäuren zu erhalten und diese als Grundlage zum verbesserten Verständnis der für die Proteinproduktion wichtigen Stoffwechselwege zu nutzen.
Kohlenhydrate als Fermentationsrohstoff
Authors: Peters D.
Published: March 2006

Durch photosynthetische Fixierung von Kohlendioxid gebildete Biomasse ist die einzige erneuerbare Kohlenstoffquelle und somit die einzige nachwachsende Rohstoffquelle für die chemische Industrie. Kohlenhydrate sind der Hauptbestandteil der Biomasse und finden sich dort insbesondere als Gerüst‐ und Speicherkohlenhydrate, aber auch als Transportkohlenhydrate sowie in Glycokonjugaten wieder. Die mengenmäßig wichtigsten natürlichen Kohlenhydrate sind Cellulose, Hemicellulosen und Stärke sowie in geringerem Ausmaß Pektine, Inuline und Saccharose. Glucose ist das wichtigste Monosaccharid von natürlichen Kohlenhydraten und damit die am häufigsten vorkommende organische Verbindung auf der Erde. Im chemisch‐technischen Bereich sind die Gewinnung von Cellulose aus Holz, die Nutzung von Stärke bei der Papierherstellung sowie die Verwendung von Glucose und Saccharose für Fermentationen die wichtigsten industriellen Anwendungen von Kohlenhydraten. Für die chemische Industrie sind Kohlenhydrate als Fermentationsrohstoff unverzichtbar. Ihre Bedeutung hat in den letzten Jahren mit dem Aufschwung von biotechnologischen Verfahren stetig zugenommen. Aufgrund ihrer überragenden Bedeutung als Fermentationsrohstoff sollen in dieser Übersicht Kohlenhydrate aus agrarischen Rohstoffen näher betrachtet werden.
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

Die 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.
Cover Picture: Tuning Wasp Toxin Structure for Nicotinic Receptor Antagonism: Cyclohexylalanine‐Containing Analogues as Potent and Voltage‐Dependent Blockers (ChemMedChem 3/2006)
Authors: Olsen Christian A. , Mellor Ian R. , Wellendorph Petrine , Usherwood Peter N. R. , Witt Matthias , Franzyk Henrik , Jaroszewski Jerzy W.
Published: March 2006

The cover picture shows an analogue of the natural wasp toxin PhTX‐433 (lower right). The natural toxin is a noncompetitive antagonist of ionotropic receptors (depicted in the lipid bilayer as space‐filling models). As PhTX‐433 is relatively nonselective in its action, solid‐phase synthetic methods have given access to analogues of this toxin that have potency toward the nicotine acetylcholine receptor in the nanomolar concentration range. For more details, see the communication by J. Jaroszewski et al. on p. 303 ff. (Thanks to Steen Drozd Lund, Flemming Steen Jørgensen, Christian Adam Olsen, Baysic Dsn, and Good Morning Technology for the graphics.)
Stable signal recovery from incomplete and inaccurate measurements
Authors: Candès Emmanuel J. , Romberg Justin K. , Tao Terence
Published: March 2006

Suppose 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

We 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

This 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

Synthesis 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

Tertiary 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

The 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

In 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

Two 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

The 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

Predicting 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

High 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

We 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

Transcription 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

Acupuncture 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

Amyloid 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

Beacon (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.
Insulin degrading enzyme is localized predominantly at the cell surface of polarized and unpolarized human cerebrovascular endothelial cell cultures
Authors: Lynch John A. , George Ana M. , Eisenhauer Patricia B. , Conn Kelly , Gao Wenwu , Carreras Isabel , Wells John M. , McKee Ann , Ullman M. David , Fine Richard E.
Published: March 2006

Insulin degrading enzyme (IDE) is expressed in the brain and may play an important role there in the degradation of the amyloid beta peptide (Aβ). Our results show that cultured human cerebrovascular endothelial cells (HCECs), a primary component of the blood–brain barrier, express IDE and may respond to exposure to low levels of Aβ by upregulating its expression. When radiolabeled Aβ is introduced to the medium of cultured HCECs, it is rapidly degraded to smaller fragments. We believe that this degradation is largely the result of the action of IDE, as it can be substantially blocked by the presence of insulin in the medium, a competitive substrate of IDE. No inhibition is seen when an inhibitor of neprilysin, another protease that may degrade Aβ, is present in the medium. Our evidence suggests that the action of IDE occurs outside the cell, as inhibitors of internalization fail to affect the rate of the observed degradation. Further, our evidence suggests that degradation by IDE occurs on the plasma membrane, as much of the IDE present in HCECs was biotin‐labeled by a plasma membrane impermeable reagent. This activity seems to be polarity dependent, as measurement of Aβ degradation by each surface of differentiated HCECs shows greater degradation on the basolateral (brain‐facing) surface. Thus, IDE could be an important therapeutic target to decrease the amount of Aβ in the cerebrovasculature. © 2006 Wiley‐Liss, Inc.
Cerebrolysin decreases amyloid‐β production by regulating amyloid protein precursor maturation in a transgenic model of Alzheimer's disease
Authors: Rockenstein Edward , Torrance Magdalena , Mante Michael , Adame Anthony , Paulino Amy , Rose John B. , Crews Leslie , Moessler Herbert , Masliah Eliezer
Published: March 2006

Cerebrolysin is a peptide mixture with neurotrophic effects that might reduce the neurodegenerative pathology in Alzheimer's disease (AD). We have previously shown in an amyloid protein precursor (APP) transgenic (tg) mouse model of AD‐like neuropathology that Cerebrolysin ameliorates behavioral deficits, is neuroprotective, and decreases amyloid burden; however, the mechanisms involved are not completely clear. Cerebrolysin might reduce amyloid deposition by regulating amyloid‐β (Aβ) degradation or by modulating APP expression, maturation, or processing. To investigate these possibilities, APP tg mice were treated for 6 months with Cerebrolysin and analyzed in the water maze, followed by RNA, immunoblot, and confocal microscopy analysis of full‐length (FL) APP and its fragments, β‐secretase (BACE1), and Aβ‐degrading enzymes [neprilysin (Nep) and insulin‐degrading enzyme (IDE)]. Consistent with previous studies, Cerebrolysin ameliorated the performance deficits in the spatial learning portion of the water maze and reduced the synaptic pathology and amyloid burden in the brains of APP tg mice. These effects were associated with reduced levels of FL APP and APP C‐terminal fragments, but levels of BACE1, Notch1, Nep, and IDE were unchanged. In contrast, levels of active cyclin‐dependent kinase‐5 (CDK5) and glycogen synthase kinase‐3β [GSK‐3β; but not stress‐activated protein kinase‐1 (SAPK1)], kinases that phosphorylate APP, were reduced. Furthermore, Cerebrolysin reduced the levels of phosphorylated APP and the accumulation of APP in the neuritic processes. Taken together, these results suggest that Cerebrolysin might reduce AD‐like pathology in the APP tg mice by regulating APP maturation and transport to sites where Aβ protein is generated. This study clarifies the mechanisms through which Cerebrolysin might reduce Aβ production and deposition in AD and further supports the importance of this compound in the potential treatment of early AD. © 2006 Wiley‐Liss, Inc.
Preliminary studies by visible and near‐infrared reflectance spectroscopy of juvenile and adult olive (Olea europaea L.) leaves
Authors: León Lorenzo , Downey Gerard
Published: March 2006

The spectral properties of olive leaves were studied by visible and near‐infrared spectroscopy to discriminate between the juvenile and adult origin of leaf samples. Spectral data from 400 to 2500 nm were recorded on 18 leaf samples from juvenile (6) and adult (12) seedling plants using four different sample presentations to the instrument. Spectra of leaves were remarkably similar owing to dominant features related to absorption by photosynthetic pigments (visible) and water (near‐infrared), although high variability was observed for all the sample presentations tested. The fibre‐optic probe presentation provided the best procedure as it maximised (in relative terms) the spectral variability attributable to differences between seedlings and minimised that arising from the sampling procedure. Principal component analysis (PCA) performed with average values per seedling showed that two groups can be clearly observed according to the origin (juvenile or adult) of the samples. This method could provide a rapid screening technique useful as a selection tool in olive breeding programmes. Copyright © 2006 Society of Chemical Industry
Seed treatments affect functional and antinutritional properties of amaranth flours
Authors: Gamel Tamer H , Linssen Jozef P , Mesallam Ahmed S , Damir Ahmed A , Shekib Lila A
Published: March 2006

The effects of seed treatments, including cooking, popping germination and flour air classification, on the functional properties and antinutritional factors of Amaranthus caudatus and Amaranthus cruentus seeds were studied. Thermal treatments increased the water absorption with a maximum value of 5.1 and 6.3 g g−1 in flour of popped seeds of both species. Generally, fat absorption increased after the treatments. Air classification and germination followed by drying at low temperature increased the foam stability of the flours, while thermal treatment and germination followed by drying at higher temperatures reduced the foam stability. All treatments except air classification decreased the emulsion stability. Also, all treatments except germination followed by drying at 30 °C increased the flour dispersibility, whereas the soluble nitrogen index was increased in the germinated seed flours and decreased in thermal treated seeds and air‐classified flours. Air classification increased the contents of phenolic compounds and phytate and decreased the contents of enzyme inhibitors, whereas the thermal treatments reduced the contents of phenolic compounds, phytate and enzyme inhibitors to a greater extent for cooking than for popping. Germination followed by drying reduced the level of phenolic compounds, phytate and enzyme inhibitors. Copyright © 2006 Society of Chemical Industry
Chemometric evaluation of relationships between retention and physicochemical parameters in terms of multidimensional liquid chromatography of peptides
Authors: Baczek Tomasz
Published: March 2006

Statistical evaluation of relationships between chromatographic retention and physicochemical descriptors of peptides was performed. The relationships describing retention were derived for a set of 98 structurally diversified peptides chromatographed on HPLC columns using acetonitrile and water with the addition of 0.1% trifluoroacetic acid as the mobile phase. It was found with the aid of multivariate principal component analysis (PCA) and factor analysis that the retention contributions of the amino acids comprising the individual peptide and the physicochemical parameters describing the bulkiness properties of peptides have the greatest influence on the retention of peptides, independent of the stationary phase used. Retention data were determined on six physicochemically different HPLC columns with the aid of experiments performed with various gradient times and column temperatures. Moreover, PCA permitted differentiation of the RP‐HPLC columns used in terms of their similarities and dissimilarities in respect of peptide separations.
Determination of beef tallow in lard through a multidimensional off‐line non‐aqueous reversed phase–argentation LC method coupled to mass spectrometry
Authors: Dugo Paola , Kumm Tiina , Fazio Alessia , Dugo Giovanni , Mondello Luigi
Published: March 2006

The presence of tallow in lard is not easy to determine, due to the similarity of the composition of these two animal fats, which differ mainly in the distribution of fatty acids (FA) in the three positions of the glycerol molecule. The determination of the composition of the triacylglycerol (TAG) fraction of lard, tallow, and their mixtures was investigated by HPLC in combination with atmospheric pressure chemical ionization mass spectrometry (APCI‐MS). The presence of tallow in lard was determined through the study of the sn‐POP/sn‐PPO ratio by multidimensional HPLC. The off‐line bidimensional system was attained through the coupling of non‐aqueous reversed phase (NARP)‐HPLC and silver ion (Ag)‐HPLC. The primary column eluate was fractionated and the fraction containing POP/PPO isomers was injected onto the secondary column, allowing the separation of positional isomers, unresolved in the first dimension. Peak assignment was carried out by combining retention data with APCI‐MS spectral information. The fatty acid distribution along the glycerol backbone, determined by Ag‐HPLC, was confirmed through diglyceride ion ratios derived from APCI‐MS analysis. Method validation was carried out in preliminary applications on standard TAGs. The analytical results obtained show that even a 5% addition of tallow to lard modifies the distribution of positional isomers.
Two‐dimensional and serial column reversed‐phase separation of phenolic antioxidants on octadecyl‐, polyethyleneglycol‐, and pentafluorophenylpropyl‐silica columns
Authors: Blahová Eva , Jandera Pavel , Cacciola Francesco , Mondello Luigi
Published: March 2006

The separation selectivity of octadecyl‐silica (C18) and of bonded pentafluorophenylpropyl‐silica (F5) and PEG‐silica columns was compared for natural phenolic antioxidants. The separation selectivities for phenolic antioxidants on C18 and F5 columns are strongly correlated, but low selectivity correlation indicating strong differences in the retention mechanism was observed between the C18 and PEG columns. Hence, the combination of a C18 and a PEG column is useful for separation of phenolic antioxidants that are not fully separated on single columns. Two‐dimensional comprehensive liquid chromatography using a short PEG‐silica column in the first dimension and a conventional C18‐silica in the second dimension has the advantage of on‐column focusing of the fractions transferred onto the C18 column in the second dimension, as a weaker mobile phase is used in the first dimension than in the second dimension. However, a stop‐flow set‐up in the first dimension system is necessary after the transfer of each fraction to the second dimension. Peak capacity is considerably larger but the separation time is much longer than with serially coupled PEG and C18 columns, which were employed for separation of beer and hop extract samples in connection with coulometric detection.
Upregulation of dopamine D2 receptors in dopaminergic drug‐naive patients with parkin gene mutations
Authors: Scherfler Christoph , Khan Naheed L. , Pavese Nicola , Lees Andrew J. , Quinn Niall P. , Brooks David J. , Piccini Paola P.
Published: March 2006

Medicated patients with Parkinsonism and parkin gene mutations have been reported to show a significant decrease in striatal dopamine D2 receptors (D2R) in comparison to medicated idiopathic Parkinson's disease (IPD) patients with similar age and disease severity. The aim of this study was to verify whether the genetic defect per se is responsible for this decrease. We have studied with [11C]raclopride (RAC) positron emission tomography (PET) in a group of 14 sporadic patients with parkin‐linked Parkinsonism, 6 of whom had never received levodopa or dopamine agonists. The remaining 8 patients had been treated with levodopa for at least 5 years. Presynaptic striatal [18F]dopa storage was not significantly different between these two groups of patients. In untreated parkin‐positive patients, significant putaminal increases in RAC‐binding potential (BP) were found in comparison to an age‐matched healthy control group by using a classical region of interest approach and statistical parametric mapping. In contrast, levodopa‐treated parkin‐positive patients showed significant decreases in RAC‐BP in the caudate and putamen when compared to an age‐matched healthy control group. The RAC PET findings revealed that striatal D2R upregulation occurs in dopaminergic drug‐naive parkin‐positive patients, in a similar fashion to the upregulation reported in drug‐naive IPD. D2R downregulation observed in medicated parkin‐positive patients, therefore, is not caused primarily by the genetic defect itself. Parkin‐positive patients appear to have a greater susceptibility to the exposure to dopaminergic medication than IPD patients, which in turn might be an indirect effect of their genetic mutation. © 2006 Movement Disorder Society
Lack of G2019S LRRK2 mutation in a cohort of Taiwanese with sporadic Parkinson's disease
Authors: Fung Hon‐Chung , Chen Chiung‐Mei , Hardy John , Hernandez Dena , Singleton Andrew , Wu Yih‐Ru
Published: March 2006

Mutations in the leucine‐rich repeat kinase 2 (LRRK2) gene have been shown to cause autosomal dominant and sporadic Parkinson's disease (PD). We report here the frequency of a common heterozygous mutation, 2877510G>A, which produces a glycine‐to‐serine amino acid substitution at codon 2019 in idiopathic Taiwanese PD. The extreme rarity of the G2019S mutation in our population suggests the occurrence of this mutation resulted from a common European founder. © 2006 Movement Disorder Society
Psychological adjustment has a greater effect on health‐related quality of life than on severity of disease in Parkinson's disease
Authors: Suzukamo Yoshimi , Ohbu Sadayoshi , Kondo Tomoyoshi , Kohmoto Junko , Fukuhara Shunichi
Published: March 2006

The objective of this study was to investigate the effect of psychological adjustment to Parkinson's disease (PD) on the health‐related quality of life (HRQL) in patients with this condition. One hundred eighty‐three patients (77 male, 106 female; mean age, 65.8 years) were evaluated using the Parkinson's Disease Questionnaire (PDQ‐39) and the Japanese version of the Nottingham Adjustment Scale (NAS‐J). Multiple regression analysis was performed using age and sex as the explanatory variables. Comparisons were made of changes in R2 when severity and psychological adjustment subscales were added. In addition, comparisons were made of HRQL scores between groups with different levels of psychological adjustment. R2 was higher when psychological adjustment was included in comparison with severity in the some subscales (emotional well‐being, stigma, social support, cognition, communication, and bodily discomfort). HRQL was significantly lower in the low‐adjustment group compared with other groups. Psychological adjustment had a greater effect than severity of disease on several subscales in the HRQL of patients with PD. This finding suggests that, in addition to any suppression of the progression of symptoms, psychological intervention may also be effective in enhancing the HRQL of patients with PD. © 2006 Movement Disorder Society
Rheumatology telephone helplines: Patient and health professionals' requirements
Authors: Brown Susan J , McCabe Candy S. , Hewlett Sarah , McDowell Jackie A. , Cushnaghan Janet , Breslin Anne M. , Stafford Sue , Carmichael Charlotte R.
Published: March 2006

Objectives: The aim of this study was to ascertain patients' and health professionals' requirements from a rheumatology helpline and how such a service should be delivered.

Methods: Self‐completed questionnaires were administered to both users of rheumatology helplines, patients and health professionals (HPs), and providers of rheumatology services at five UK NHS trusts. Additional data were sought from experts in the field. Information was elicited on access to the service, preferred waiting time for response to a call, acceptability of an answerphone and choice of HP responding. Quantitative data were analysed using percentages and Chi‐squared tests. Open questions were analysed as free text responses, and organized into clusters of themes.

Results: A total of 607 questionnaires were returned, 523 from users (411 patients, 112 health professionals) and 84 from providers. There were no significant differences across the five Trusts. The top six reasons for patients contacting the helpline were: advice on changes in condition, drug information, understanding symptoms, blood results, information on diagnosis, and appointment queries. All groups recommended a return call on the same day and were happy to leave an answerphone message. HP users requested additional access via e‐mail and fax. Rheumatology practitioners were deemed the most appropriate personnel to staff a helpline.

Conclusions: The findings of this study have contributed a valuable insight into the essential components of a rheumatology helpline service from a user and provider perspective. These data will add to existing recommendations for the management of a rheumatology helpline service and ultimately contribute to a proposal for national guidelines. Copyright © 2006 John Wiley & Sons, Ltd.
Small proportions: what to report for confidence intervals?
Authors: Tobi Hilde , van den Berg Paul B. , de Jong‐van den Berg Lolkje TW
Published: March 2006

The original article to which this Erratum refers was published in Pharmacoepidemiology and Drug Safety 2005; 14: 239–247.
Synthesis of diblock copolymers by combining stable free radical polymerization and atom transfer radical polymerization
Authors: Shi Yan , Fu Zhifeng , Li Bingyi , Yang Wantai
Published: March 2006

A stable nitroxyl radical functionalized with an initiating group for atom transfer radical polymerization (ATRP), 4‐(2‐bromo‐2‐methylpropionyloxy)‐2,2,6,6‐tetramethyl‐1‐piperidinyloxy (Br‐TEMPO), was synthesized by the reaction of 4‐hydroxyl‐2,2,6,6‐tetramethyl‐1‐piperidinyloxy with 2‐bromo‐2‐methylpropionyl bromide. Stable free radical polymerization of styrene was then carried out using a conventional thermal initiator, dibenzoyl peroxide, along with Br‐TEMPO. The obtained polystyrene had an active bromine atom for ATRP at the ω‐end of the chain and was used as the macroinitiator for ATRP of methyl acrylate and ethyl acrylate to prepare block copolymers. The molecular weights of the resulting block copolymers at different monomer conversions shifted to higher molecular weights and increased with monomer conversion. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2468–2475, 2006
Electrochemical polymerization of aniline in the SDS/n‐C5H11OH/H2SO4(aq) lyotropic liquid crystal
Authors: Guo Rong , Li Zhong Chun , Liu Tian Qing
Published: March 2006

Electrochemical polymerization of aniline was performed by the method of ultramicroelectrode cyclic voltammetry in the lamellar liquid crystal and hexagonal liquid crystal of SDS/n‐C5H11OH/H2SO4(aq) system. The results indicate that the electrochemical polymerization of aniline can be catalyzed by the SDS/n‐C5H11OH/H2SO4(aq) lyotropic liquid crystal. The polymerization potential of aniline is smaller in the lyotropic liquid crystal system than that in the 0.10 mol L−1 sulfuric acid solution. The catalytic efficiency and polymerization rate of aniline increase with then‐pentanol content, but decrease with the increase of the SDS content or [PhNH2/H2SO4(aq)] content. Moreover, the catalytic efficiency of the lamellar liquid crystal exceeds that of the hexagonal liquid crystal in the SDS/n‐C5H11OH/H2SO4(aq) system. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2388–2394, 2006