bluuebunny/crossref_metadata_2025 huggingface dataset:
Human matrix metalloproteinases: Characteristics and pathologic role in altering mesangial homeostasis
Authors: Keeling John , Herrera Guillermo A.
Published: February 2008

Matrix metalloproteinases are zinc dependent endopeptidases belonging to the M10 family of the metalloproteinase superfamily. They are ubiquitous enzymes, structurally and functionally related, with a high degree of sequence homology. They are primarily involved in extracellular matrix (ECM) turn‐over and cell migration through their expanding repertoire of substrate affinities. Twenty three different forms of human MMPs have been described to be arranged in eight distinct structural classes. Their interactions with tissue inhibitors of metalloproteinases (TIMPs), and other indigenous inhibitors have been well documented. This manuscript reviews pertinent information available on matrix metalloproteinases and TIMPs in the literature. Light chain‐mediated glomerular injury represents an excellent example of how metalloproteinases participate in altering mesangial homeostasis. Investigations regarding these conditions have shown that the physico–chemical characteristics of the light chains govern the pattern of renal damage that will ensue with the mesangium representing the critical site where pathological alterations are centered. The mesangium is either replaced or expanded depending on the light chains involved in the pathologic process. Microsc. Res. Tech., 2008. © 2008 Wiley‐Liss, Inc.
Integrin‐dependent translational control: Implication in cancer progression
Authors: Chung Jun , Kim Tae Hyong
Published: February 2008

The importance of translational control in cancer progression has been underscored by a number of recent studies. However, little is known how cancer cells maintain their high efficiency of translation. Here, we summarize studies that support the role of integrins in translational control, especially at the initiation step, and discuss the various mechanisms by which integrins regulate the recruitment of translational machinery. This review also examines the hypothesis that integrins contribute to various aspects of cancer progression such as proliferation, survival, angiogenesis, and invasion through translational control. Microsc. Res. Tech. 2008. © 2008 Wiley‐Liss, Inc.
Test–retest reliability of a functional MRI anticipatory anxiety paradigm in healthy volunteers
Authors: Schunck Thérèse , Erb Gilles , Mathis Alexandre , Jacob Nathalie , Gilles Christian , Namer Izzie Jacques , Meier Dieter , Luthringer Rémy
Published: February 2008

Purpose

To evaluate the reproducibility of neural activations induced by an anticipatory anxiety provocation challenge in healthy volunteers.

Materials and Methods

Fourteen healthy male volunteers participated in two separate functional MRI (fMRI) sessions in which they underwent a paradigm based on anticipation of aversive transcutaneous electrical nerve stimulations. This paradigm consisted of alternating presentation of red circles associated with the likelihood that aversive stimuli may be given and blue circles during which the subjects knew that no shock could be given. Anxiety state was compared before the fMRI sessions and during the threat periods using clinical scales (Hamilton, STAI‐Y1), the Bond and Lader Visual Analogue Scale, and self‐rating scales of apprehension and stimulus aversivity.

Results

The selected paradigm induced anticipatory anxiety of moderate intensity as suggested by clinical scales and apprehension rating, without any habituation to the somatosensory stimulus across sessions. Compared to rest periods, threat of the aversive stimulus induced clear brain activation in anticipatory anxiety‐related areas: frontal/prefrontal cortex, insula, lentiform nucleus, temporal pole, and cingulate cortex. Anxiety symptoms and cerebral activity were reproducible across sessions.

Conclusion

The fMRI paradigm and its assessment method include all criteria to speed up the evaluation and the development of new anxiolytics. J. Magn. Reson. Imaging 2008;27:459–468. © 2008 Wiley‐Liss, Inc.
Precipitation forecast over western Himalayas using k‐nearest neighbour method
Authors: Dimri A. P. , Joshi P. , Ganju A.
Published: February 2008

Knowledge of precipitation over the western Himalayas is of utmost importance during winter season (December, January, February, and March—DJFM) due to extreme weather conditions. During winter, eastward moving synoptic weather systems called western disturbances (WDs) yield enormous amount of precipitation over this region. This amount of precipitation by a number of WDs keeps on accumulating and poses an avalanche threat to the habitat. Not only this, low temperature conditions along with precipitation form extremely hostile winter conditions to live with. In the present study, the nearest neighbour (NN) method is used to forecast probability of precipitation (PoP) occurrence/non‐occurrence and its quantity. The method of NN is introduced to visualize the results. The NN forecast technique attempts to compare similar situations in the past with current data and assumes that similar events are likely to occur under similar conditions. At present, only nine important weather variables are considered for generating a 3‐day advance forecast of PoP occurrence/non‐occurrence and quantity at eight representative observatories in Jammu and Kashmir (J&K), the northmost state of India. This state receives maximum amount of solid precipitation in the form of snow during winter. Past data of 8–14 years (between 1988 and 2003) is considered, from which the nearest days are looked for and tested with data of 2–4 years (between 2003 and 2005). PoP occurrence/non‐occurrence is well predicted by k‐Nearest Neighbour (k‐NN) sampling method. It is evident from the results that the model is able to give the projections 3 days in advance, with an accuracy of 71–88%. Probability forecast of occurrence of precipitation is predicted well by the present model setup, but the quantitative precipitation forecast (QPF) is an important issue that still needs improvement, keeping in view the topographical and land‐use heterogeneity of the area under study. Copyright © 2008 Royal Meteorological Society
Storage stability of an egg yolk cream formulation: texture and microbiological assessment
Authors: Fundo Joana F , Quintas Mafalda AC , Brandão Teresa RS , Silva Cristina LM
Published: February 2008

BACKGROUND: Egg yolk cream is confectioned with egg yolk, sugar and water. Pasteurized liquid eggs may be used in order to increase product safety, although these samples may differ from the classic ones produced with raw eggs. The objective was to evaluate and compare the stability (physicochemical characteristics, such as texture assessment, pH and water activity, and microbiological assessment) of a classic formulation and an alternative one produced with pasteurized eggs, during storage at 6, 26, 30 and 37 °C.

RESULTS: From a microbiological point of view (mesophile and psychrotrophic activity), no differences were observed in either formulations. At 6 and 26 °C, rheological behaviour of both formulations remained approximately constant. At 30 and 37 °C, differences were only detected after 20 days of storage. Texture was better retained in samples prepared with pasteurized eggs, while the classic samples showed an increase in complex viscosity.

CONCLUSION: Cream storage did not require refrigeration. In terms of texture and microbial load, results obtained at 6 and 26 °C were identical. The formulations only differed in texture when stored at 30 and 37 °C and for long periods. These conclusions may allow reduction of costs related to refrigerated distribution/storage of either classic or alternative formulations. Copyright © 2008 Society of Chemical Industry
Alternative organic solvents for HILIC separation of cisplatin species with on‐line ICP‐MS detection
Authors: Hemström Petrus , Nygren Yvonne , Björn Erik , Irgum Knut
Published: February 2008

Several low volatile organic solvents were evaluated as organic modifiers in eluents for HILIC separations of cisplatin species to optimize the on‐line coupling of HILIC to inductively coupled plasma MS (ICP‐MS). The aim was to identify a solvent giving low solvent vapor loading of the ICP, to maximize analyte sensitivity and minimize carbon depositions on instrumental parts, while retaining chromatographic performance. The best overall performance of the HILIC‐ICP‐MS system for the analysis of cisplatin was achieved using 1,4‐dioxane as eluent, yielding high retention and an HILIC type retention mechanism, at the expense of a 50% drop in column efficiency due to the higher viscosity of 1,4‐dioxane compared to the more commonly used HILIC solvent ACN. Using 1,4‐dioxane as solvent in HILIC provides the best compromise between carbon deposition and separation efficiency among a series of high‐boiling water‐miscible solvents tested.
Enantioseparation of cetirizine by sulfated‐β‐cyclodextrin‐mediated capillary electrophoresis
Authors: Chou Yu‐Wei , Huang Wei‐Shan , Ko Chen‐Chun , Chen Su‐Hwei
Published: February 2008

A sulfated β‐cyclodextrin (sulfated β‐CD)‐mediated capillary electrophoresis method is described for the enantioseparation of cetirizine using achiral cefazolin as an internal standard. The enantioseparation of the drug was performed in a borate buffer (5 mM, pH 8.7) with 1% sulfated β‐CD (w/v) as chiral selector at 10 kV. Several parameters affecting the separation were studied, including the pH and the concentration of borate buffer and chiral selector. Under optimized conditions, a baseline separation of two enantiomers was achieved in less than 7 min. Using cefazolin as an internal standard (IS), the linear range of the method for the determination of levocetirizine was over 1.0 to 50.0 μg/mL; the detection limit (signal‐to‐noise ratio = 3) of levocetirizine was 0.5 μg/mL. The method allowed the enantioseparation of cetirizine in bulk samples and enantiomeric purity evaluation of levocetirizine (R‐enantiomer) in pharmaceutical tablets (Xyzal®), and it was also found to be suitable for enantioseparation in human plasma.
Human liver dihydrodiol dehydrogenase 1‐catalyzed reaction generating 9α,11β‐prostaglandin F2 from prostaglandin D2 followed by micellar electrokinetic chromatography
Authors: Inagaki Shinsuke , Esaka Yukihiro , Deyashiki Yoshihiro , Uno Bunji , Hara Akira , Toyo'oka Toshimasa
Published: February 2008

An enzyme reaction converting prostaglandin D2 (PGD2) into 9α,11β‐prostaglandin F2 (9α,11β‐PGF2) by a human liver‐originated recombinant dihydrodiol dehydrogenase 1 (DD1) has been studied using CE. Four prostaglandins, viz. PGD2, 9α,11β‐PGF2, PGE2, and PGF2a (see Fig. 1, the latter two major PGs are possibly coexisting compounds in the assay mixtures), were completely separated by using SDS or PEG as buffer additives. Because analysis times in the SDS system were shorter than in the PEG system, SDS was employed in measurements of the enzyme activity of DD1. The pH dependence and the reaction temperature dependence of enzyme activity have been studied. The present method enabled us to detect all of the participants in the enzyme reaction: PGD2, 9α,11β‐PGF2, nicotinamide adenine dinucleotide phosphate (NADPH), and NADP+. Thus, direct, comprehensive, and reliable analysis of the enzyme reaction becomes possible. Enzyme activity has hitherto been estimated indirectly from the decrease of fluorescence derived from NADPH as an index of progress of the enzyme reactions in batch methods employed in conventional studies. In addition, the low sample consumption characteristic of CE should be a significant advantage of the present method in characterization of less commonly available enzymes such as the recombinant species used in this work.
Validation of an ultra‐fast UPLC‐UV method for the separation of antituberculosis tablets
Authors: Nguyen Dao T.‐T. , Guillarme Davy , Rudaz Serge , Veuthey Jean‐Luc
Published: February 2008

A simple method using ultra performance LC (UPLC) coupled with UV detection was developed and validated for the determination of antituberculosis drugs in combined dosage form, i. e. isoniazid (ISN), pyrazinamide (PYR) and rifampicin (RIF). Drugs were separated on a short column (2.1 mm×50 mm) packed with 1.7 μm particles, using an elution gradient procedure. At 30°C, less than 2 min was necessary for the complete separation of the three antituberculosis drugs, while the original USP method was performed in 15 min. Further improvements were obtained with the combination of UPLC and high temperature (up to 90°C), namely HT‐UPLC, which allows the application of higher mobile phase flow rates. Therefore, the separation of ISN, PYR and RIF was performed in less than 1 min. After validation (selectivity, trueness, precision and accuracy), both methods (UPLC and HT‐UPLC) have proven suitable for the routine quality control analysis of antituberculosis drugs in combined dosage form. Additionally, a large number of samples per day can be analysed due to the short analysis times.
Separation and determination of estrone in environmental and drinking water using molecularly imprinted solid phase extraction coupled with HPLC
Authors: Wang Shuo , Xu Zhixiang , Fang Guozhen , Zhang Yan , He Jinxing
Published: February 2008

Estrone has been identified as an important potential endocrine‐disrupting compound, so that sensitive and reliable analytical methods are required for its determination and the assurance of human health. Using estrone as the template, acrylamide as the functional monomer, and methacryloxypropyltrimethoxysilane as the cross‐linker, an organic‐inorganic hybrid material has been synthesized by the molecular imprinting technique combined with a non‐hydrolytic so‐gel process. The synthesized polymer was characterized by FT‐IR and static adsorption experiments, and the results showed that it had good recognition and selective ability for estrone. A novel method for separation and determination of trace estrone in water samples was developed using molecularly imprinted solid phase extraction coupled with HPLC. Under the selected experimental condition, the detection limit (S/N = 3) was 9.3 ng/L, and the RSD for five replicate extractions of 10 μg/L estrone was less than 5.0%. This method was employed for quantitative determination of estrone in river, lake, and tap water with recoveries ranging from 83.38 to 98.12%.
Knowledge management for corporate entrepreneurship and growth: a case study
Authors: Guadamillas Fátima , Donate Mario J. , Pablo Jesús D. Sánchez de
Published: February 2008

This study presents a case of corporate entrepreneurship analyzed from a Knowledge‐based perspective as an extension of the Resource‐based View (RBV) of the firm. This approach proposes that the development of knowledge can underpin the growth of the firm through corporate entrepreneurship. Following this perspective, we analyze the way an established firm uses resources and capabilities, especially its accumulated knowledge, as a foundation on which to develop a growth strategy through diversification to related businesses in the fields of electronics and Information Technology (IT). Moreover, we identify some of the most important factors contributing to the success of this strategy, such as the internal development and integration of relevant technological knowledge, human resources (HR) policies, organizational flexibility, knowledge management tools based on IT, and purchase of companies and cooperation agreements for the acquisition of external knowledge. Copyright © 2008 John Wiley & Sons, Ltd.
Susceptibility of pRb‐deficient epidermis to chemical skin carcinogenesis is dependent on the p107 allele dosage
Authors: Santos Mirentxu , Ruiz Sergio , Lara M. Fernanda , Segrelles Carmen , Moral Marta , Martínez‐Cruz Ana Belén , Ballestín Claudio , Lorz Corina , García‐Escudero Ramón , Paramio Jesús M.
Published: February 2008

Functional inactivation of the pRb‐dependent pathway is a general feature of human cancer. However, only a reduced spectrum of tumors displays inactivation of the Rb gene. This can be attributed, at least partially, to the possible overlapping functions carried out by the related retinoblastoma family members p107 and p130. We observed that loss of pRb in epidermis, using the Cre/LoxP technology, results in proliferation and differentiation defects. These alterations are partially compensated by the elevation in the levels of p107. Moreover, epidermis lacking pRb and p107, but not pRb alone, develops spontaneous tumors, and double deficient primary keratinocytes are highly susceptible to Ha‐ras‐induced transformation. Two‐stage chemical carcinogenesis experiments in mice lacking pRb in epidermis revealed a reduced susceptibility in papilloma formation and an increase in the malignant conversion. We have now explored whether the loss of one p107 allele, inducing a decrease in the levels of p107 up to normal levels could restore the susceptibility of pRb‐deficient skin to two‐stage protocol. We observed partial restoration in the incidence, number, and size of tumors. However, there is no increased malignancy despite sustained p53 activation. We also observed a partial reduction in the levels of proapoptotic proteins in benign papillomas. These data confirm our previous suggestions on the role of p107 as a tumor suppressor in epidermis in the absence of pRb. © 2008 Wiley‐Liss, Inc.
Emotional speech in Parkinson's disease
Authors: Möbes Janine , Joppich Gregor , Stiebritz Frank , Dengler Reinhard , Schröder Christine
Published: February 2008

Patients with Parkinson's disease (PD) tend to speak monotonously with minor modulation of pitch and intensity. The goal of this study was to find out whether these speech changes can be explained mainly by motor impairment, i.e. akinesia and rigidity of the articulatory apparatus, or whether alterations of emotional processing play an additional role. Sixteen patients with mild PD and 16 healthy controls (HC) were compared. Fundamental frequencies (pitch) and intensities (loudness) were determined as (1) maximal upper and lower values achieved in nonemotional speech (phonation capacity), (2) upper and lower values used when speaking “Anna” in emotional intonation (neutral, sad, happy) as requested (production task), or (3) when imitating a professional speaker (imitation task). Although groups did not significantly differ in their phonation capacity, patients showed a significantly smaller pitch and intensity range than HC in the production task. In the imitation task, however, ranges were again similar. These results suggest that alterations of emotional processing contribute to speech changes in PD, especially regarding emotional prosody, in addition to motor impairment. © 2008 Movement Disorder Society
Validation of the “QUICK” questionnaire—A tool for diagnosis of “wearing‐off” in patients with Parkinson's disease
Authors: Martinez‐Martin Pablo , Tolosa Eduardo , Hernandez Basilio , Badia Xavier ,   ValidQUICK Study Group
Published: February 2008

The main objective of the present study was to test the validity of a 19‐items instrument (QUICK Questionnaire, QQ) as a tool for screening of WO. Two hundred twenty‐two patients (36.0% without WO; 64.0% with mild or moderate/severe WO) were included. Diagnosis of WO by the participant neurologist was considered the “gold standard.” The complete Unified Parkinson's Disease Rating Scale battery, the Cumulative Illness Rating Scale‐Geriatrics, and a form about WO presence and severity were completed by the neurologist. Patients independently completed the QQ just before the clinical assessment. As a whole, patients with WO were more disabled than patients without and patients with moderate/severe WO were in worse condition than patients with mild WO. The number of QQ symptoms declared to improve usually after the following dose of medication was 1.0 ± 1.8 in the group without WO, but 6.0 ± 3.8 in patients with WO (P < 0.001). A two QQ positive symptoms cut‐off showed the following attributes: sensitivity, 88%; specificity, 80%; positive predictive value, 88.7%; negative predictive value, 79%; diagnostic accuracy, 85%; positive and negative likelihood ratios 4.4 and 0.15, respectively. The area under the ROC curve resulted 0.90 (CI95%: 0.86–0.94%). In summary, the QQ proved to be a valid screening tool to identify WO in PD patients. To our knowledge, the QQ is the only validated tool for diagnosis of WO. © 2008 Movement Disorder Society
Huntington's disease as caused by 34 CAG repeats
Authors: Andrich Jürgen , Arning Larissa , Wieczorek Stefan , Kraus Peter H. , Gold Ralf , Saft Carsten
Published: February 2008

Huntington's disease (HD) is an autosomal dominantly inherited neurodegenerative disorder caused by an abnormal expansion of a polymorphic stretch of CAG repeats in the coding 5′ part of the HD gene on chromosome 4p. Expansions of CAG blocks beyond 35 repeats are associated with the clinical presentation of HD. There is an intermediate range of rare alleles between 27 and 35 CAG repeats with a higher risk for further expansion in subsequent generations. Here, we report a 75‐year‐old male with clinical features of HD and 34 CAG repeat units. © 2008 Movement Disorder Society
Discriminating raining from non‐raining cloud areas at mid‐latitudes using meteosat second generation SEVIRI night‐time data
Authors: Thies B. , Nauss T. , Bendix J.
Published: February 2008

A new method for the delineation of precipitation during night‐time using multispectral satellite data is proposed. The approach is not only applicable to the detection of mainly convective precipitation by means of the commonly used relation between infrared cloud‐top temperature and rainfall probability but enables also the detection of stratiform precipitation (e.g. in connection with mid‐latitude frontal systems).

The presented scheme is based on the conceptual model that precipitating clouds are characterized by a combination of particles large enough to fall, an adequate vertical extension [both represented by the cloud water path (CWP)], and the existence of ice particles in the upper part of the cloud. As no operational retrieval exists for Meteosat Second Generation (MSG) to compute the CWP during night‐time, suitable combinations of brightness temperature differences (ΔT) between the thermal bands of Meteosat Second Generation‐Spinning Enhanced Visible and InfraRed Imager (MSG SEVIRI, ΔT3.9–10.8, ΔT3.9–7.3, ΔT8.7–10.8, ΔT10.8–12.1) are used to infer implicit information about the CWP and to compute a rainfall confidence level. ΔT8.7–10.8 and ΔT10.8–12.1 are particularly considered to supply information about the cloud phase.

Rain area delineation is realized by using a minimum threshold of the rainfall confidence. To obtain a statistical transfer function between the rainfall confidence and the channel differences, the value combination of the channel differences is compared with ground‐based radar data. The retrieval is validated against independent radar data not used for deriving the transfer function and shows an encouraging performance as well as clear improvements compared to existing optical retrieval techniques using only IR thresholds for cloud‐top temperature. Copyright © 2008 Royal Meteorological Society
Ultra‐fast and accurate assessment of cardiac function in rats using accelerated MRI at 9.4 Tesla
Authors: Schneider Jürgen E. , Lanz Titus , Barnes Hannah , Medway Debra , Stork Lee‐Anne , Lygate Craig A. , Smart Sean , Griswold Mark A. , Neubauer Stefan
Published: February 2008

MRI can accurately and reproducibly assess cardiac function in rodents but requires relatively long imaging times. Therefore, parallel imaging techniques using a 4‐element RF‐coil array and MR sequences for cardiac MRI in rats were implemented at ultra‐high magnetic fields (9.4 Tesla [T]). The hypothesis that these developments would result in a major reduction in imaging time without loss of accuracy was tested on female Wistar rats under isoflurane anesthesia. High‐resolution, contiguous short‐axis slices (thickness 1.5 mm) were acquired covering the entire heart. Two interleaved data sets (i) with the volume coil (eight averages) and (ii) with the four‐element coil array (one average) were obtained. In addition, two‐, three‐, and fourfold accelerated data sets were generated through postprocessing of the coil array data, followed by a TGRAPPA reconstruction, resulting in five data sets per rat (in‐plane voxel size 100 × 100 μm). Using a single blinded operator, excellent agreement was obtained between volume coil (acquisition time: 88 min) and the fourfold accelerated (<3 min) data sets (e.g., LV mass 436 ± 21 mg vs 433 ± 19 mg; ejection fraction 74 ± 5% vs 75 ± 4%). This finding demonstrates that it is possible to complete a rat cine‐MRI study under 3 min with low variability and without losing temporal or spatial resolution, making high throughput screening programs feasible. Magn Reson Med 59:636–641, 2008. © 2008 Wiley‐Liss, Inc.
Metabolic markers of neuronal injury correlate with SIV CNS disease severity and inoculum in the macaque model of neuroAIDS
Authors: Lentz Margaret R. , Westmoreland Susan V. , Lee Vallent , Ratai Eva‐Maria , Halpern Elkan F. , González R. Gilberto
Published: February 2008

In vivo MR spectroscopy (MRS) studies have shown reductions in NAA/Cr levels in patients with severe neurocognitive deficits due to AIDS dementia complex (ADC), also known as neuroAIDS. The relationship between the cellular changes within the brain during neuroAIDS and the role of NAA/Cr as a metabolic marker remains unclear. In order to clarify the relationship between NAA/Cr and disease severity we utilized the simian immunodeficiency virus (SIV)/macaque model of encephalitis. High‐field proton MRS was performed on extracted metabolites from frontal cortex tissue samples of 29 rhesus macaques (6 healthy, 23 moribund with AIDS). Neuropathologic determination of encephalitis severity for each animal was completed and was found to correlate with NAA/Cr levels. Decreases in Glu/Cr and GABA/Cr may indicate that both excitatory and inhibitory neurons are affected. Highly significant correlations between NAA/Cr, Glu/Cr, and GABA/Cr were observed. These neuronal metabolites were also decreased in the absence of classical SIV encephalitis (SIVE). At any disease classification, animals inoculated with SIVmac251 were found to have lower levels of NAA/Cr than animals inoculated with SIVmac239. In considering therapy for neuroAIDS the findings here support prevention of the encephalitic process, but suggest that suppressing the formation of multinucleated giant cells alone would be insufficient to prevent neuronal injury. Magn Reson Med 59:475–484, 2008. © 2008 Wiley‐Liss, Inc.
Decontamination of hypercubes by mobile agents
Authors: Flocchini Paola , Huang Miao Jun , Luccio Flaminia L.
Published: February 2008

In this article we consider the decontamination problem in a hypercube network of size n. The nodes of the network are assumed to be contaminated and they have to be decontaminated by a sufficient number of agents. An agent is a mobile entity that asynchronously moves along the network links and decontaminates all the nodes it touches. A decontaminated node that is not occupied by an agent is re‐contaminated if it has a contaminated neighbor. We consider some variations of the model based on the capabilities of mobile agents: locality, where the agents can only access local information; visibility, where they can “see” the state of their neighbors; and cloning, where they can create copies of themselves. We also consider synchronicity as an alternative system requirement. For each model, we design a decontamination strategy and we make several observations. For agents with locality, our strategy is based on the use of a coordinator that leads the other agents. Our strategy results in an optimal number of agents, $\Theta ({n \over \sqrt{\log n}})$, and requires O(n log n) moves and O(n log n) time steps. For agents with visibility, we assume that the agents can move autonomously. In this setting, our decontamination strategy achieves an optimal time complexity (log n time steps), but the number of agents increases to $ {n \over 2}$. Finally, we show that when the agents have the capability to clone combined with either visibility or synchronicity, we can reduce the move complexity—which becomes optimal—at the expense of an increase in the number of agents. © 2008 Wiley Periodicals, Inc. NETWORKS, 2008
Cyclic sums, network sharing, and restricted edge cuts in graphs with long cycles
Authors: Rautenbach Dieter , Volkmann Lutz
Published: February 2008

We study graphs G = (V,E) containing a long cycle which for given integers a1, a2,…,ak ∈
\input amssym ${\Bbb N}$
have an edge cut whose removal results in k components with vertex sets V1,V2,…,Vk such that |Vi| ≥ ai for 1 ≤ i ≤ k. Our results closely relate to problems and recent research in network sharing and network reliability. © 2008 Wiley Periodicals, Inc. NETWORKS, 2008
An efficient reduced‐order modeling approach for non‐linear parametrized partial differential equations
Authors: Nguyen N. C. , Peraire J.
Published: February 2008

For general non‐linear parametrized partial differential equations (PDEs), the standard Galerkin projection is no longer efficient to generate reduced‐order models. This is because the evaluation of the integrals involving the non‐linear terms has a high computational complexity and cannot be pre‐computed. This situation also occurs for linear equations when the parametric dependence is nonaffine. In this paper, we propose an efficient approach to generate reduced‐order models for large‐scale systems derived from PDEs, which may involve non‐linear terms and nonaffine parametric dependence. The main idea is to replace the non‐linear and nonaffine terms with a coefficient‐function approximation consisting of a linear combination of pre‐computed basis functions with parameter‐dependent coefficients. The coefficients are determined efficiently by an inexpensive and stable interpolation at some pre‐computed points. The efficiency and accuracy of this method are demonstrated on several test cases, which show significant computational savings relative to the standard Galerkin projection reduced‐order approach. Copyright © 2008 John Wiley & Sons, Ltd.
Trends in treatment‐related deaths (TRDs) in childhood cancer and leukemia over time: A follow‐up of patients included in the childhood cancer registry of the Rhône‐Alpes region in France (ARCERRA)
Authors: Freycon Fernand , Trombert‐Paviot Béatrice , Casagranda Léonie , Bertrand Yves , Plantaz Dominique , Marec‐Bérard Perrine
Published: February 2008

Background

We assessed the number and causes of treatment‐related deaths (TRDs) in childhood cancer over time and correlated them with adherence to therapeutic guidelines.

Procedure

We compared two cohorts of children of the Childhood Cancer Registry of the Rhône‐Alpes Region: Cohort I (1987–1992, 909 patients) and Cohort II (1996–1999, 648 patients).

Results

In all cancers together, 75 TRDs were reported in Cohort I and 24 in Cohort II (P = 0.001). Cumulative incidence at 5 years declined from 7.9% to 4.1%, and overall survival (OS) increased from 71.0% to 77.2%. TRDs declined by nearly 10‐fold in patients with solid malignant tumors (P = 0.02) and central nervous system tumors (P = 0.001), but OS improved for patients with solid malignant tumors only (P = 0.01). No difference was observed in treatment‐ and transplantation‐related deaths in patients with acute lymphoblastic leukemia (ALL) and acute myeloblastic leukemia (AML), but OS was better in patients with AML (P = 0.02). Between the two cohorts, transplantation‐related mortality did not decrease and was higher at 5 years in patients with ALL who received unrelated‐matched donor transplants (41.3%) than in those receiving sibling‐matched donor transplants (18.7%). OS improved in the respective transplant groups (37.0% and 64.2%). Severe graft‐versus‐host disease was also observed among patients with ALL (P = 0.036). The decrease in TRDs was correlated with compliance to therapeutic guidelines.

Conclusion

Although mortality declined, improved adherence to therapeutic guidelines and more restricted indications of allograft are needed to preclude further treatment‐ and transplantation‐related deaths, particularly among those with leukemia. Pediatr Blood Cancer 2008;50:1213–1220. © 2008 Wiley‐Liss, Inc.
Hyperleukocytosis from arsenic trioxide
Authors: Levy Michael , Wofford Marcia M. , Powell Bayard L. , McLean Thomas W.
Published: February 2008

We report the case of a 14‐year‐old male treated with arsenic trioxide for recurrent acute promyelocytic leukemia. He developed hyperleukocytosis (WBC 111.6 × 109/L) which then resolved while continuing daily arsenic. Hyperleukocytosis without other complications may not be an indication for adding cytotoxic therapy or steroids, nor for discontinuing arsenic trioxide therapy in children. Pediatr Blood Cancer 2008;50:1265–1267. © 2008 Wiley‐Liss, Inc.
Simulation of the residual stresses in the contour laser welding of thermoplastics
Authors: Potente H. , Wilke L. , Ridder H. , Mahnken R. , Shaban A.
Published: February 2008

This article presents the influence of the process parameters in laser transmission welding for plastics on the residual stress in the welded part. The contour welding process is modeled by means of finite element (FE) simulation. In this process, the weld seam is only partially heated, i.e., only part of it melts. The calculations are performed using a material model that describes the time‐dependent temperature and stress development in a plate geometry, making allowance for the material's asymmetric compressive‐tensile behavior. Experimental data were measured under different load cases to present the time‐dependent material behavior, and then implemented in numerical terms by formulating the necessary constitutive equations. The calculations to simulate the influence of process parameters on the residual stress behavior were performed using a finite element model that was developed. The simulation covers the entire welding process, including the heating and cooling stages. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Mixed methods research in school psychology: A mixed methods investigation of trends in the literature
Authors: Powell Heather , Mihalas Stephanie , Onwuegbuzie Anthony J. , Suldo Shannon , Daley Christine E.
Published: February 2008

This article illustrates the utility of mixed methods research (i.e., combining quantitative and qualitative techniques) to the field of school psychology. First, the use of mixed methods approaches in school psychology practice is discussed. Second, the mixed methods research process is described in terms of school psychology research. Third, the current state of affairs with respect to mixed methods designs in school psychology research is illustrated through a mixed methods analysis of the types of empirical studies published in the four leading school psychology journals between 2001 and 2005. Only 13.7% of these studies were classified as representing mixed methods research. We conclude that this relatively small proportion likely reflects the fact that only 3.5% of graduate‐level school psychology programs appear to require that students enroll in one or more qualitative and/or mixed methods research courses, and only 19.3% appear to offer one or more qualitative courses as an elective. Finally, the utility of mixed methods research is illustrated by critiquing select monomethod (i.e., qualitative or quantitative) and mixed methods studies conducted on the increasingly important topic of bullying. We demonstrate how using mixed methods techniques results in richer data being collected, leading to a greater understanding of underlying phenomena. © 2008 Wiley Periodicals, Inc.
Gender matters in transition to adulthood: A survey study of adolescents with disabilities and their families
Authors: Powers Kristin , Hogansen Jennifer , Geenen Sarah , Powers Laurie E. , Gil‐Kashiwabara Eleanor
Published: February 2008

This survey study explored gender differences in transition imperatives and opportunities for youth with disabilities (N = 521). Results indicated that males and females differ in terms of the adult outcomes they hope to achieve, transition training opportunities they have received, and their access to teachers and other nonfamilial adults to assist them. Youth and parents who responded to the survey indicated that gender stereotypes continue to exist and that these stereotypes result in lowered expectations for girls. Gender stereotypes were found to vary by ethnicity. Access to health insurance and a good doctor were rated as top priorities for all youth transitioning to adulthood. Implications for educators, psychologists, and counselors are discussed. © 2008 Wiley Periodicals, Inc.
Relationships among stress, coping, and mental health in high‐achieving high school students
Authors: Suldo Shannon M. , Shaunessy Elizabeth , Hardesty Robin
Published: February 2008

This study investigates the relationships among stress, coping, and mental health in 139 students participating in an International Baccalaureate (IB) high school diploma program. Mental health was assessed using both positive indicators (life satisfaction, academic achievement, academic self‐efficacy) and negative indicators (psychopathology) of adolescent social‐emotional and school functioning. Findings include that students in an IB program perceive significantly more stress than a sample of 168 of their general education peers, and that specific coping styles are differentially related to mental health outcomes in this subgroup of high‐achieving high school students. Furthermore, coping styles (specifically, anger and positive appraisal) moderate the influence of stress on global life satisfaction and internalizing symptoms of psychopathology. © 2008 Wiley Periodicals, Inc.
Chemische Reaktion perfekt kontrolliert
Authors: Dürr Stephan
Published: February 2008

Physiker am Max‐Planck‐Institut für Quantenoptik können das Zustandekommen einer chemischen Bindung zwischen zwei Atomen voll kontrollieren. Dabei kommt es zu quantenmechanischen Oszillationen zwischen ungebundenen Atompaaren und gebundenen Molekülen.
Antimaterie in der Milchstraße
Authors: Bührke Thomas
Published: February 2008

Vor etwa 30 Jahren entdeckten Astronomen Gammastrahlung, die aus der Richtung des Zentrums unserer Milchstraße kommt. Sie besitzt eine Energie von 511 keV und stammt somit offenbar von der Vernichtung von Elektronen und deren Antiteilchen, Positronen. Da Antimaterie in der Natur normalerweise nicht vorkommt, wurden zahlreiche Erklärungen für dieses Phänomen vorgeschlagen. Auch exotische Theorien, wonach die Strahlung beim Zerfall von hypothetischen Dunkle‐Materie‐Teilchen frei wird, wurden diskutiert. Jetzt hat ein internationales Team um Georg Weidenspointner vom Max‐Planck‐Institut für extraterrestrisch Physik in Garching herausgefunden, dass die Positronen wahrscheinlich in ungewöhnlichen Doppelstern‐Systemen entstehen.
Synthesis of polypeptides from activated urethane derivatives of α‐amino acids
Authors: Kamei Yasutaka , Sudo Atsushi , Nishida Haruo , Kikukawa Kiyoshi , Endo Takeshi
Published: February 2008

A series of activated urethane‐type derivatives of α‐amino acids were synthesized and applied to polypeptide synthesis. The urethane used herein, N‐(4‐nitrophenoxycarbonyl)‐α‐amino acids 1, were synthesized by N‐carbamoylation of γ‐benzyl‐L‐glutamate, β‐benzyl‐L‐aspartate, L‐leucine, L‐phenylalanine, and L‐proline, with 4‐nitrophenyl chloroformate. When 1 was dissolved in N,N‐dimethylacetamide (DMAc) and heated at 60 °C, it was smoothly converted into the corresponding polypeptides with releasing 4‐nitrophenol and carbon dioxide. Spectroscopic analyses of the obtained polypeptides revealed that they were comparable with the authentic polypeptides synthesized by the ring‐opening polymerizations of amino acid N‐carboxyanhydrides (NCAs). Besides the successful polycondensations of a series of 1, their polycondensations of 1a and other 1 were also successfully carried out to obtain the corresponding statistic copolypeptides. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2525–2535, 2008
The conserved salt bridge linking two C‐terminal β/α units in homodimeric triosephosphate isomerase determines the folding rate of the monomer
Authors: Reyes‐López César A. , González‐Mondragón Edith , Benítez‐Cardoza Claudia G. , Chánez‐Cárdenas María E. , Cabrera Nallely , Pérez‐Montfort Ruy , Hernández‐Arana Andrés
Published: February 2008

Triosephosphate isomerase (TIM), whose structure is archetypal of dimeric (β/α)8 barrels, has a conserved salt bridge (Arg189–Asp225 in yeast TIM) that connects the two C‐terminal β/α segments to rest of the monomer. We constructed the mutant D225Q, and studied its catalysis and stability in comparison with those of the wild‐type enzyme. Replacement of Asp225 by Gln caused minor drops in kcat and KM, but the catalytic efficiency (kcat/KM) was practically unaffected. Temperature‐induced unfolding–refolding of both TIM samples displayed hysteresis cycles, indicative of processes far from equilibrium. Kinetic studies showed that the rate constant for unfolding was about three‐fold larger in the mutant than in wild‐type TIM. However, more drastic changes were found in the kinetics of refolding: upon mutation, the rate‐limiting step changed from a second‐order (at submicromolar concentrations) to a first‐order reaction. These results thus indicate that renaturation of yTIM occurs through a uni–bimolecular mechanism in which refolding of the monomer most likely begins at the C‐terminal half of its polypeptide chain. From the temperature dependence of the refolding rate, we determined the change in heat capacity for the formation of the transition state from unfolded monomers. The value for the D225Q mutant, which is about 40% of the corresponding value for yTIM, would implicate the folding of only three quarters of a monomer chain in the transition state. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Enhanced self‐ordering of anodic ZrO2 nanotubes in inorganic and organic electrolytes using two‐step anodization
Authors: Berger Steffen , Faltenbacher Josef , Bauer Sebastian , Schmuki Patrik
Published: February 2008

This work reports on the optimized growth of self‐ordered ZrO2 nanotubes in inorganic water‐based and organic electrolyte systems containing small amounts of fluoride employing a two‐step anodization process. We show how surface pretreatments of the metallic Zr substrate can drastically improve the growth and morphology of the resulting anodic ZrO2 nanotube arrays. Using two step anodization and employing organic electrolytes, highly regular and ordered nanotubular ZrO2 oxide layers can be grown to significantly increased tube lengths compared with aqueous electrolytes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Instream flow determination using a multiple input fuzzy‐based rule system: a case study
Authors: Ahmadi‐Nedushan B. , St‐Hilaire A. , Bérubé M. , Ouarda T. B. M. J. , Robichaud É.
Published: February 2008

The attempts made to manage water to meet human requirements should also consider the needs of freshwater species and ecosystems. There are many tools available to assess instream flow needs, one of which is the use of habitat preference models. In this study, a fuzzy approach was used for modelling habitat preferences for two life stages of Atlantic salmon (Salmo salar). Experienced fish biologists and technicians contributed to the development of fuzzy sets and fuzzy preference rules for spawning and parr habitat. Fuzzy sets were defined for water depth, velocity and substrate composition. Fuzzy preference rules for the two life stages were then defined as sets of IF–THEN rules relating the physical attributes to habitat suitability. The fuzzy suitability indices are then used to obtain weighted usable area (WUA) at different discharges and to estimate the ecologic flow required to preserve habitat. Different methods are applied to combine the membership function and rules defined by the experts. A sensitivity analysis of rules of the combined system indicated that a limited number of rules are determinant and results are highly dependent on the consequences of these rules. A modification in the consequence of these rules can significantly alter WUA estimations. It is therefore recommended to combine the knowledge of many experts in the elicitation process and to quantify the uncertainty associated with the combination of expert knowledge. Copyright © 2007 John Wiley & Sons, Ltd.
Sustainable reservoir operation: can we generate hydropower and preserve ecosystem values?
Authors: Jager Henriette I. , Smith Brennan T.
Published: February 2008

Hydroelectric power provides a cheap source of electricity with few carbon emissions. Yet, reservoirs are not operated sustainably, which we define as meeting societal needs for water and power while protecting long‐term health of the river ecosystem. Reservoirs that generate hydropower are typically operated with the goal of maximizing energy revenue, while meeting other legal water requirements. Reservoir optimization schemes used in practice do not seek flow regimes that maximize aquatic ecosystem health. Here, we review optimization studies that considered environmental goals in one of three approaches. The first approach seeks flow regimes that maximize hydropower generation, while satisfying legal requirements, including environmental (or minimum) flows. Solutions from this approach are often used in practice to operate hydropower projects. In the second approach, flow releases from a dam are timed to meet water quality constraints on dissolved oxygen (DO), temperature and nutrients. In the third approach, flow releases are timed to improve the health of fish populations. We conclude by suggesting three steps for bringing multi‐objective reservoir operation closer to the goal of ecological sustainability: (1) conduct research to identify which features of flow variation are essential for river health and to quantify these relationships, (2) develop valuation methods to assess the total value of river health and (3) develop optimal control softwares that combine water balance modelling with models that predict ecosystem responses to flow. Copyright © 2007 John Wiley & Sons, Ltd.
The cover time of the giant component of a random graph
Authors: Cooper Colin , Frieze Alan
Published: February 2008

We study the cover time of a random walk on the largest component of the random graph Gn,p. We determine its value up to a factor 1 + o(1) whenever np = c > 1, c = O(lnn). In particular, we show that the cover time is not monotone for c = Θ(lnn). We also determine the cover time of the k‐cores, k ≥ 2. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Mobile GPS carrier phase tracking using a novel intelligent dual‐loop receiver
Authors: Mao Wei‐Lung , Chen An‐Bang
Published: February 2008

Carrier phase information is necessary for accurate measurements in global positioning system (GPS) applications. This paper presents a novel intelligent GPS carrier tracking loop with variable‐bandwidth characteristics for fast acquisition and better tracking capability in the presence of dynamic environments. Our dual‐loop receiver is composed of a frequency‐locked loop‐assisted phase‐locked loop structure, the fuzzy controllers (FCs), and the ATAN discriminator functions. The soft‐computing FCs provide the time‐varying loop gains to perform accurate and reliable control of the dual‐loop paradigm. Once the phase dynamic errors become large under kinematic conditions, the fuzzy loop gains increase adaptively and achieve rapid acquisition. On the other hand, when the tracking errors approach zero in the steady state, the loop gains decrease and the corresponding dual‐loop receiver returns to a narrowband system. Four types of carrier phase signals, i.e. phase offset, decaying sinusoidal phase jitter, frequency offset, and frequency ramp offset, are considered to emulate realistic mobile circumstances. Simulation results show that our proposed receiver does achieve a superior performance over conventional tracking loops in terms of faster settling time and wider acquisition range while preventing the occurrence of cycle slips. Copyright © 2008 John Wiley & Sons, Ltd.