bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphanylborohydrides: First Assessment of the Relative Lewis Basicities of [BH3PPh2]–, CH3PPh2, and HPPh2
Authors: Dornhaus Franz , Bolte Michael , Lerner Hans‐Wolfram , Wagner Matthias
Published: March 2006

The compounds K[PPh2], HPPh2, CH3PPh2, BH3(H)PPh2, BBr3(H)PPh2, BH3(CH3)PPh2, BBr3(CH3)PPh2, [H2PPh2]I, [CH3(H)PPh2]I, [(CH3)2PPh2]I, and K[(BH3)2PPh2] have been investigated by NMR spectroscopy. In addition, X‐ray crystal structures have been determined for K(18‐crown‐6)[PPh2], BBr3(H)PPh2, BBr3(CH3)PPh2, [H2PPh2]I, [CH3(H)PPh2]I, [(CH3)2PPh2]I, and K(18‐crown‐6)[(BH3)2PPh2]. An evaluation of coupling constants (e.g. 1JPCi; Ci = ipso carbon atom of a phenyl ring) augmented by an inspection of key structural parameters (e.g. the angles Ci–P–Ci′) leads to the conclusion that dative bonds originating from ligand [BH3PPh2]– possess a significantly higher p character than dative bonds involving the ligands HPPh2 and CH3PPh2. The 1JPB values obtained for BH3(H)PPh2, BH3(CH3)PPh2, and [(BH3)2PPh2]– suggest [BH3PPh2]– to form the strongest [BH3] adduct of all three compounds which is in agreement with the results of displacement reactions employing the couples CH3PPh2/[(BH3)2PPh2]– and [BH3PPh2]–/BH3(CH3)PPh2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
The topographic data source of digital terrain models as a key element in the accuracy of hydraulic flood modelling
Authors: Casas A. , Benito G. , Thorndycraft V.R. , Rico M.
Published: March 2006

The effects of the topographic data source and resolution on the hydraulic modelling of floods were analysed. Seven digital terrain models (DTMs) were generated from three different altimetric sources: a global positioning system (GPS) survey and bathymetry; high‐resolution laser altimetry data LiDAR (light detection and ranging); and vectorial cartography (1:5000). Hydraulic results were obtained, using the HEC‐RAS one‐dimensional model, for all seven DTMs. The importance of the DTM's accuracy on the hydraulic modelling results was analysed within three different hydraulic contexts: (1) the discharge and water surface elevation results from the hydraulic model; (2) the delineation of the flooded area; and (3) the relative sensitivity of the hydraulic model to changes in the Manning's n roughness coefficient. The contour‐based DTM was the least accurate with a root mean square error (RMSE) of 4·5 m in the determination of the water level and a variation of up to 50 per cent in the estimation of the inundated area of the floodplain. The GPS‐based DTM produced more realistic water surface elevation results and variations of up to 8 per cent in terms of the flooded area. The laser‐based model's RMSE for water level was 0·3 m, with the flooded area varying by less than 1 per cent. The LiDAR data also showed the greatest sensitivity to changes in the Manning's roughness coefficient. An analysis of the effect of mesh resolution indicated an influence on the delineation of the flooded area with variations of up to 7·3 per cent. In addition to determining the accuracy of the hydraulic modelling results produced from each DTM, an analysis of the time–cost ratio of each topographic data source illustrates that airborne laser scanning is a cost‐effective means of developing a DTM of sufficient accuracy, especially over large areas. Copyright © 2006 John Wiley & Sons, Ltd.
Relative contributions of runoff and sediment from sources within a road prism and implications for total sediment delivery
Authors: Croke Jacky , Mockler Simon , Hairsine Peter , Fogarty Peter
Published: March 2006

This study examines runoff and sediment generation rates within the road prism on unsealed road segments in the Cuttagee Creek catchment near Bermagui in New South Wales, Australia. A large (600 m2) rainfall simulator was used to measure runoff and sediment yields from each of the potential sediment and runoff sources and pathways. These included the road surface, table‐drain, upslope contributing area and cutslope face, and the entire road segment as measured at the drain outlet. Experiments were conducted on two major types of road (ridge‐top and cut‐and‐fill) of varying traffic usage and maintenance standard for two 30‐minute simulations of increasing rainfall intensity. From the range of possible sources within the road prism, the road surface produced the dominant source of excess runoff and sediment at each site with limited contributions from the table‐drain, cutslope face or contributing hillslope. Sediment generation varied significantly with road usage and traffic intensity. Road usage was strongly related to the amount of loose available sediment as measured prior to the experiments. Table‐drains acted primarily as sediment traps during the low rainfall event but changes in sediment concentration within the drains were observed as runoff volumes increased during the higher rainfall event of 110 mm h−1, releasing sediment previously stored in litter and organic dams. The experiments demonstrate the potential roles of various features of the road prism in the generation and movement of sediment and water. Copyright © 2006 John Wiley & Sons, Ltd.
Gullying and erosion control at archaeological sites in Grand Canyon, Arizona
Authors: Pederson Joel L. , Petersen Paul A. , Dierker Jennifer L.
Published: March 2006

Gully erosion of cultural sites in Grand Canyon National Park is an urgent management problem that has intensified in recent decades, potentially related to the effects of Glen Canyon Dam. We studied 25 gullies at nine sites in Grand Canyon over the 2002 monsoon–erosion season to better understand the geomorphology of the gully erosion and the effectiveness of erosion‐control structures (ECS) installed by the park under the direction of the Zuni Conservation Program. Field results indicate that Hortonian overland flow leads to concentrated flow in gullies and erosion focused at knickpoints along channels as well as at gully heads. Though groundcover type, soil shear strength and permeability vary systemat‐ically across catchments, gradient and, to a lesser degree, contributing drainage area seem to be the first‐order controls on gully extent, location of new knickpoints, and ECS damage. The installed ECS do reduce erosion relative to reaches without them and initial data suggest woody checkdams are preferable to rock linings, but maintenance is essential because damaged structures can exacerbate erosion.

Topographic data from intensive field surveys and detailed photogrammetry provide slope–contributing area data for gully heads that have a trend consistent with previous empirical and theoretical formulations from a variety of landscapes. The same scaling holds below gully heads for knickpoint and ECS topographic data, with threshold coefficients the lowest for gully heads, slightly higher for knickpoints, and notably higher for damaged ECS. These topographic thresholds were used with 10‐cm digital elevation models to create simple predictive models for gully extent and structure damage. The model predictions accounted for the observed gullies but there are also many false‐positives. Purely topographical models are probably inadequate at this scale and application, but models that also parameterize the variable soil properties across sites would be useful for predicting erosion problems and ECS failure. Copyright © 2006 John Wiley & Sons, Ltd.
Geostatistical mapping of geomorphic variables in the presence of trend
Authors: Lark R. M. , Webster R.
Published: March 2006

Mapping geomorphic variables geostatistically, specifically by kriging, runs into difficulties when there is trend. The reason is that the variogram required for the kriging must be of residuals from any trend, which in turn cannot be estimated optimally by the usual method of trend surface analysis because the residuals are correlated. The difficulties can be overcome by the use of residual maximum likelihood (REML) to estimate both the trend and the variogram of the residuals simultaneously.

We summarize the theory of REML as it applies to kriging in the presence of trend. We present the equations to show how estimates of the trend are combined with kriging of residuals to give empirical best linear unbiased predictions (E‐BLUPs). We then apply the method to estimate the height of the sub‐Upper‐Chalk surface beneath the Chiltern Hills of southeast England from 238 borehole data. The variogram of the REML residuals is substantially different from that computed by ordinary least squares (OLS) analysis. The map of the predicted surface is similar to that made from kriging with the OLS variogram. The variances, however, are substantially larger because (a) they derive from a variogram with a much larger sill and (b) they include the uncertainty of the estimate of the trend. Copyright © 2006 John Wiley & Sons, Ltd.
Efficacy of atelocollagen honeycomb scaffold in bone formation using KUSA/A1 cells
Authors: Rodriguez Andrea Paola , Missana Liliana , Nagatsuka Hitoshi , Gunduz Mehmet , Tsujigiwa Hidetsugu , Rivera Rosario , Nagai Noriyuki
Published: March 2006

To induce new bone formation, mesenchymal stem cells were seeded onto atelocollagen honeycomb scaffold. We evaluated the efficacy of this scaffold combined with KUSA/A1 cells in vivo. KUSA/A1 cells alone and with atelocollagen were implanted in the subcutaneous pockets of 4‐week‐old male SCID mice. The transplants were subjected to radiographical, histological, and immunohistochemical examinations after 2 and 4 weeks of implantation. Radiographically, both KUSA/A1 cells alone and KUSA/A1‐atelocollagen showed some radiopaque areas formation but the latter disclosed a larger amount. Histologically, KUSA/A1 cells alone showed few small islands of new bone formation surrounded by a thin layer of cellular proliferation. On the other hand, KUSA/A1‐atelocollagen revealed abundant new bone formation as well as cellular proliferation. We also determined the immunolocalization of type I collagen, CD34, osteocalcin, osteopontin, and PCNA in this newly formed bone. Our results indicated that collagen scaffold plays an important role allowing vessel formation and cell anchorage, especially through the proliferation and differentiation process in a confined space. This study supports tissue engineering as an alternative for treating different target diseases, such as trauma or congenital defects, and enhances existing therapeutic applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Functionalized chitosan/NIPAM (HEMA) hybrid polymer networks as inserts for ocular drug delivery: Synthesis, in vitro assessment, and in vivo evaluation
Authors: Verestiuc Liliana , Nastasescu Oana , Barbu Eugen , Sarvaiya Indrajeetsinh , Green Keith L. , Tsibouklis John
Published: March 2006

A series of hybrid polymeric hydrogels, prepared by the reaction of acrylic acid‐functionalized chitosan with either N‐isopropylacrylamide or 2‐hydroxyethyl methacrylate monomers, were synthesized, pressed into minitablets, and investigated for their ability to act as controlled release vehicles for ophthalmic drug delivery. For comparison, interpolymeric complex analogues synthesized using the same monomers and pure, unfunctionalized chitosan were examined by means of an identical characterization protocol. The effects of network structure and composition upon the swelling properties, adhesion behavior, and drug release characteristics were investigated. Comparative in vitro studies employing chloramphenicol, atropine, norfloxacin, or pilocarpine informed the selection of drug‐specific carrier compositions for the controlled delivery of these compounds. In addition, in vivo (rabbit model) experiments involving the delivery of pilocarpine indicated that chitosan‐based hybrid polymer networks containing 2‐hydroxyethyl methacrylate are useful carriers for the delivery of this therapeutic agent. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2006
Ectopia cordis in a fetus with trisomy 18
Authors: Shaw Sheng‐Wen , Cheng Po‐Jen , Chueh Ho‐Yen , Chang Shuenn‐Dyh , Soong Yung‐Kuei
Published: March 2006

Trisomy 18 is the second‐most common autosomal trisomy and represents one third of the chromosomal trisomies identified prenatally. We present a case of a fetus with trisomy 18 in which thoracoabdominal ectopia cordis was detected prenatally; it was noted as a dominant defect on a sonographic examination performed at 19 weeks' gestation. Furthermore, our case exhibits a rare type of multiple‐marker screening result with increased maternal serum alpha‐fetoprotein. This case demonstrates the need for thorough sonographic evaluation of the fetal thoracoabdominal wall as early as possible, because fetal ectopia cordis can be the major abnormality of trisomy 18. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound 34:95–98, 2006
B‐flow sonographic demonstration for assessing carotid atherosclerosis in young patients with heterozygous familial hypercholesterolemia
Authors: Noto Nobutaka , Okada Tomoo , Yoshino Yayoi , Harada Kensuke
Published: March 2006

Purpose:

To determine whether bloodstream swirls detected with B‐mode flow (B‐flow) sonography at the region of the carotid bifurcation can predict the early progression of atherosclerosis, we prospectively examined the relationships between the size of bloodstream swirls as identified with B‐flow sonography, the local mechanical behavior of the common carotid artery (CCA), and some cardiovascular risk factors in young patients with heterozygous familial hypercholesterolemia (FH).

Methods:

Thirty‐eight young patients (mean age 25.8 ± 14.1 years) with FH were evaluated for the following parameters: age, sex, body mass index, degree of dyslipidemia, presence of a plaque, intima‐media thickness (IMT), elastic modulus (Ep) and internal diameter of the CCA via duplex scan, wall shear stress, maximal diameter of the bloodstream swirl (Sm) at bifurcation, maximal diameter of the CCA (Cm) at the level of the swirl's center, and diameter ratio (Sm/Cm) via B‐flow sonography.

Results:

Bloodstream swirls of varying size at the site of bifurcation were observed in all patients. Six (15.7%) out of 38 patients exhibited plaques at bifurcation. All plaques were located at the far wall and were in contact with the distal portion of the bloodstream swirl as observed with B‐flow sonography. Univariate analysis revealed that Sm/Cm and Sm were positively correlated with age, presence of a plaque, IMT, and Ep and were negatively correlated with shear stress. Multivariate analysis revealed that Sm was significantly correlated with age (P < 0.01) and Ep (P < 0.05).

Conclusions:

Our results suggest that a bloodstream swirl visualized at the carotid bifurcation with B‐flow sonography may be an indicator of a local mechanism for the age‐related progression of atherosclerosis in young patients with FH. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound 34:43–49, 2006
Early evolution of vertebrate skeletal tissues and cellular interactions, and the canalization of skeletal development
Authors: Donoghue Philip Conrad James , Sansom Ivan James , Downs Jason Philip
Published: March 2006

The stratigraphically earliest and the most primitive examples of vertebrate skeletal mineralization belong to lineages that are entirely extinct. Therefore, palaeontology offers a singular opportunity to address the patterns and mechanisms of evolution in the vertebrate mineralized skeleton. We test the two leading hypotheses for the emergence of the four skeletal tissue types (bone, dentine, enamel, cartilage) that define the present state of skeletal tissue diversity in vertebrates. Although primitive vertebrate skeletons demonstrate a broad range of tissues that are difficult to classify, the first hypothesis maintains that the four skeletal tissue types emerged early in vertebrate phylogeny and that the full spectrum of vertebrate skeletal tissue diversity is explained by the traditional classification system. The opposing hypothesis suggests that the early evolution of the mineralized vertebrate skeleton was a time of plasticity and that the four tissue types did not emerge until later. On the basis of a considerable, and expanding, palaeontological dataset, we track the stratigraphic and phylogenetic histories of vertebrate skeletal tissues. With a cladistic perspective, we present findings that differ substantially from long‐standing models of tissue evolution. Despite a greater diversity of skeletal tissues early in vertebrate phylogeny, our synthesis finds that bone, dentine, enamel and cartilage do appear to account for the full extent of this variation and do appear to be fundamentally distinct from their first inceptions, although why a higher diversity of tissue structural grades exists within these types early in vertebrate phylogeny is a question that remains to be addressed. Citing recent evidence that presents a correlation between duplication events in secretory calcium‐binding phosphoproteins (SCPPs) and the structural complexity of mineralized tissues, we suggest that the high diversity of skeletal tissues early in vertebrate phylogeny may result from a low diversity of SCPPs and a corresponding lack of constraints on the mineralization of these tissues.J. Exp. Zool. (Mol. Dev. Evol.) 306B, 2006. © 2006 Wiley‐Liss, Inc.
Multislice dark‐blood carotid artery wall imaging: A 1.5 T and 3.0 T comparison
Authors: Koktzoglou Ioannis , Chung Yiu‐Cho , Mani Venkatesh , Carroll Timothy J. , Morasch Mark D. , Mizsei Gabor , Simonetti Orlando P. , Fayad Zahi A. , Li Debiao
Published: March 2006

Purpose

To compare two multislice turbo spin‐echo (TSE) carotid artery wall imaging techniques at 1.5 T and 3.0 T, and to investigate the feasibility of higher spatial resolution carotid artery wall imaging at 3.0 T.

Materials and Methods

Multislice proton density‐weighted (PDW), T2‐weighted (T2W), and T1‐weighted (T1W) inflow/outflow saturation band (IOSB) and rapid extended coverage double inversion‐recovery (REX‐DIR) TSE carotid artery wall imaging was performed on six healthy volunteers at 1.5 T and 3.0 T using time‐, coverage‐, and spatial resolution–matched (0.47 × 0.47 × 3 mm3) imaging protocols. To investigate whether improved signal‐to‐noise ratio (SNR) at 3.0 T could allow for improved spatial resolution, higher spatial resolution imaging (0.31 × 0.31 × 3 mm3) was performed at 3.0 T. Carotid artery wall SNR, carotid lumen SNR, and wall‐lumen contrast‐to‐noise ratio (CNR) were measured.

Results

Signal gain at 3.0 T relative to 1.5 T was observed for carotid artery wall SNR (223%) and wall‐lumen CNR (255%) in all acquisitions (P < 0.025). IOSB and REX‐DIR images were found to have different levels of SNR and CNR (P < 0.05) with IOSB values observed to be larger. Normalized to a common imaging time, the higher spatial resolution imaging at 3.0 T and the lower spatial resolution imaging at 1.5 T provided similar levels of wall‐lumen CNR (P = NS).

Conclusion

Multislice carotid wall imaging at 3.0 T with IOSB and REX‐DIR benefits from improved SNR and CNR relative to 1.5 T, and allows for higher spatial resolution carotid artery wall imaging. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Proteinaceous inhibitors of carbohydrate‐active enzymes in cereals: implication in agriculture, cereal processing and nutrition
Authors: Juge Nathalie , Svensson Birte
Published: March 2006

Enzymes that degrade, modify, or create glycosidic bonds are involved in carbohydrate biosynthesis and remodelling. Microbial carbohydrate‐active enzymes form the basis of current green technology in the food, feed, starch, paper and pulp industries and the revolution in genomics may offer long‐term gains on the quality and quantity of the raw materials. Proteinaceous inhibitors of carbohydrate‐active enzymes (α‐amylase, limit‐dextrinase, polygalacturonase, pectin lyase, pectin methylesterase, invertase and xyloglucan endoglucanase) naturally occur in plants where they are involved in various roles from plant defence to metabolism. Xylanase inhibitors represent the latest addition to this growing family. In this review, we will focus on the inhibitors of carbohydrate‐active enzymes present in cereals, mostly represented by α‐amylase and xylanase inhibitors, and summarise the existing knowledge on their structure, function, and implication in cereal processing, agriculture and nutrition. Copyright © 2006 Society of Chemical Industry
‘We are not eating our own food here’: food security and the cash economy in Eastern Uganda
Authors: Whyte M. A. , Kyaddondo D.
Published: March 2006

In this paper we explore changes in agriculture and provisioning in Bunyole County, located in Tororo District on Uganda's eastern border. Since the 1980s parts of the region have experienced a ‘rice boom’ based on the cultivation of paddy rice in irrigated schemes and seasonal swamps. During the same period, the cultivation of cotton, the traditional cash crop, has declined precipitously. Many households in the region are no longer self‐sufficient in food, and food security is a common concern. Drawing both on anthropological field studies in contrasting parts of Bunyole County (1992–3 and 2001–2), as well as long‐term field research in Bunyole that started in 1969, we examine changes in farming systems and land use, in the gender‐based division of labour in family production, and in the interdependence of families and individuals as expressed in social exchange. We trace the increasing importance of trade in food crops of all sorts and in particular the significance for the local rice economy of an emerging year‐round market for agricultural labour. Finally we examine the developing and changing discourse about ‘food’—as a commercial, a nutritional and a symbolic commodity—and the corresponding discourse about ‘money’. We see food security—at household level and in regions—as an outcome of the strategic actions of individuals. However, we also argue that local debates about food security reflect a changing relationship between ‘food’ and ‘money’—a change that involves both social and productive relationships. In eastern Bunyole these changes are expressed in terms of the new rice economy but, we suggest, the changes are more fundamental, and can be seen in many parts of Uganda. Copyright © 2006 John Wiley & Sons, Ltd.
Trends over a decade of pediatric liver transplantation in the United States
Authors: Feng Sandy , Si Ming , Taranto Sarah E. , McBride Maureen A. , Mudge Christine , Stritzel Susan , Roberts John P. , Rosenthal Philip
Published: March 2006

During the last 10 to 15 years, medical and surgical innovations have established pediatric liver transplantation as the optimal therapy for children suffering acute and chronic liver disease. We hypothesized that the profile of current pediatric liver transplant recipients would differ significantly from that of an earlier era. We collected and compared data regarding the characteristics of children undergoing liver transplantation alone in 2 eras separated by more than a decade from the Organ Procurement and Transplantation Network/United Network for Organ Sharing database. Transplant recipients from March 1, 2002 to December 31, 2004, compared to those from January 1, 1990, to December 31, 1992, tended to be more evenly distributed across age, race/ethnicity, and disease etiology. There was a major shift toward utilization of partial grafts from both deceased and living donors to achieve transplantation for the youngest children (<1 and 1–5 yr) in particular. However, in spite of these innovative transplant strategies and only a modest increase in demand for pediatric liver transplantation, wait list times for both pediatric candidates and recipients have still increased between eras. In conclusion, the sobering reality that mortality on the waiting list remains highest for the youngest pediatric liver candidates frames our challenge for the next decade.
Liver Transpl 12:578–584, 2006.

© 2006 AASLD.
Preoperative characteristics and intraoperative transfusion and vasopressor requirements in patients with low vs. high MELD scores
Authors: Xia Victor W. , Du Bin , Braunfeld Michelle , Neelakanta Gundappa , Hu Ke-Qin , Nourmand Hamid , Levin Philip , Enriquez Ronald , Hiatt Jonathan R. , Ghobrial Mark R. , Farmer Douglas G. , Busuttil Ronald W. , Steadman Randolph H.
Published: March 2006

Recent changes in organ allocation based on the model for end-stage liver disease (MELD) prioritize the most ill patients on the waiting list for liver transplantation. While patients undergoing liver transplantation in the MELD era are more acutely ill, the impact of the policy changes on perioperative management has not been completely assessed. We retrospectively reviewed the records of 124 primary adult liver transplant patients. Patients were divided into low (≤30) and high MELD (>30) score groups. Preoperative characteristics and intraoperative management were compared between the 2 groups. Patients with high MELD scores had lower baseline hematocrit and fibrinogen levels and were more likely to require ventilatory and vasopressor support before transplantation. Intraoperative transfusion requirements and use of vasopressors were also significantly increased in patients with high MELD scores compared to patients with low MELD scores. In conclusion, these data suggest that pretransplant MELD scores provide important information for perioperative management of patients undergoing liver transplantation.
Liver Transpl 12:614–620, 2006.

© 2006 AASLD.
Disseminated histoplasmosis in a liver transplant recipient
Authors: Oh Young S. , Lisker-Melman Mauricio , Korenblat Kevin M. , Zuckerman Gary R. , Crippin Jeffrey S.
Published: March 2006

A 61-yr-old liver transplant recipient presented with abdominal cramping and nonbloody diarrhea resulting in orthostasis. Multiple ulcerations throughout the colon were seen during endoscopy, and biopsies from the ulcer edges revealed histoplasmosis. Treatment with a course of itraconazole improved the diarrhea. The patient later presented with pericarditis and symptomatic pleural effusions, the latter of which was confirmed to be a result of disseminated histoplasmosis. Treatment with amphotericin B led to resolution. Histoplasmosis should be considered in liver transplant patients with diarrhea and large ulcers in the colon. The presence of disseminated histoplasmosis should be ruled out once colonic histoplasmosis has been diagnosed.
Liver Transpl 12:677–681, 2006.

© 2006 AASLD.
Compatibility Investigations on Polymer‐Fiber‐Reinforced Cements Modified with Polymer Latexes
Authors: Rottstegge Jörg , Han Charles C. , Hergeth Wolf Dieter
Published: March 2006

Summary: In construction, polymer fibers are commonly applied beside steel, glass and mineral fibers to improve material's flexibility to shear stress. As in other composite systems, there are compatibility problems present between the fibers and the cement due to the different chemical natures and the different thermal expansion coefficients of the cement and the polymers. Within this study the interactions between two Portland cements and polymer fibers were investigated by SEM and solid‐state NMR spectroscopy. To improve the wetting ability of the polymer fibers by the cement matrix, redispersible latex powders were successfully applied to improve the adhesion between the cement matrix and the fibers. Within this study, several solid‐state nuclear magnetic resonance (NMR) spectroscopy methods, detecting 1H, 13C, 27Al and 29Si nuclei, and scanning electron microscopy (SEM) were applied. Thus, cement pastes, inorganic additives and organic admixtures could be monitored individually.

SEM images of the interface between poly(propylene) fibers and Portland cement, hardened and hydrated in the presence of a 2 wt.‐% poly[(vinyl acetate)‐co‐ethylene] latex.

magnified image

SEM images of the interface between poly(propylene) fibers and Portland cement, hardened and hydrated in the presence of a 2 wt.‐% poly[(vinyl acetate)‐co‐ethylene] latex.
Mass spectrometry in grape and wine chemistry. Part II: The consumer protection
Authors: Flamini Riccardo , Panighel Annarita
Published: March 2006

Controls in food industry are fundamental to protect the consumer health. For products of high quality, warranty of origin and identity is required and analytical control is very important to prevent frauds. In this article, the “state of art” of mass spectrometry in enological chemistry as a consumer safety contribute is reported. Gas chromatography‐mass spectrometry (GC/MS) and liquid‐chromatography‐mass spectrometry (LC/MS) methods have been developed to determine pesticides, ethyl carbamate, and compounds from the yeast and bacterial metabolism in wine. The presence of pesticides in wine is mainly linked to the use of dicarboxyimide fungicides on vineyard shortly before the harvest to prevent theBotrytis cinereaattack of grape. Pesticide residues are regulated at maximum residue limits in grape of low ppm levels, but significantly lower levels in wine have to be detected, and mass spectrometry offers effective and sensitive methods. Moreover, mass spectrometry represent an advantageous alternative to the radioactive‐source‐containing electron capture detector commonly used in GC analysis of pesticides. Analysis of ochratoxin A (OTA) in wine by LC/MS and multiple mass spectrometry (MS/MS) permits to confirm the toxin presence without the use of expensive immunoaffinity columns, or time and solvent consuming sample derivatization procedures. Inductively coupled plasma‐mass spectrometry (ICP/MS) is used to control heavy metals contamination in wine, and to verify the wine origin and authenticity. Isotopic ratio‐mass spectrometry (IRMS) is applied to reveal wine watering and sugar additions, and to determine the product origin and traceability. © 2006 Wiley Periodicals, Inc.
Radial nerve repetitive stimulation in myasthenia gravis
Authors: Petretska Adriana , Jarrar Randa , Rubin Devon I.
Published: March 2006

The purpose of this study was to compare the diagnostic yield of repetitive radial nerve stimulation (RNS) while recording from extensor indicis proprius (EIP) to other commonly used muscle–nerve combinations in patients with myasthenia gravis (MG). Radial RNS with recording from EIP was performed in 20 controls and 20 patients with MG. It revealed an abnormal decrement at rest in 35% of patients compared to 11% with ulnar nerve stimulation, 64% with spinal accessory nerve stimulation, and 74% with facial nerve stimulation. Radial‐EIP RNS is a reliable technique in the evaluation of MG and appears more sensitive than ulnar nerve RNS. Muscle Nerve, 2006
Contractual agreements for coordination and vendor‐managed delivery under explicit transportation considerations
Authors: Toptal Ayşegül , Çetinkaya Sıla
Published: March 2006

We consider the coordination problem between a vendor and a buyer operating under generalized replenishment costs that include fixed costs as well as stepwise freight costs. We study the stochastic demand, single‐period setting where the buyer must decide on the order quantity to satisfy random demand for a single item with a short product life cycle. The full order for the cycle is placed before the cycle begins and no additional orders are accepted by the vendor. Due to the nonrecurring nature of the problem, the vendor's replenishment quantity is determined by the buyer's order quantity. Consequently, by using an appropriate pricing schedule to influence the buyer's ordering behavior, there is an opportunity for the vendor to achieve substantial savings from transportation expenses, which are represented in the generalized replenishment cost function.

For the problem of interest, we prove that the vendor's expected profit is not increasing in buyer's order quantity. Therefore, unlike the earlier work in the area, it is not necessarily profitable for the vendor to encourage larger order quantities. Using this nontraditional result, we demonstrate that the concept of economies of scale may or may not work by identifying the cases where the vendor can increase his/her profits either by increasing or decreasing the buyer's order quantity. We prove useful properties of the expected profit functions in the centralized and decentralized models of the problem, and we utilize these properties to develop alternative incentive schemes for win–win solutions. Our analysis allows us to quantify the value of coordination and, hence, to identify additional opportunities for the vendor to improve his/her profits by potentially turning a nonprofitable transaction into a profitable one through the use of an appropriate tariff schedule or a vendor‐managed delivery contract. We demonstrate that financial gain associated with these opportunities is truly tangible under a vendor‐managed delivery arrangement that potentially improves the centralized solution.

Although we take the viewpoint of supply chain coordination and our goal is to provide insights about the effect of transportation considerations on the channel coordination objective and contractual agreements, the paper also contributes to the literature by analyzing and developing efficient approaches for solving the centralized problem with stepwise freight costs in the single‐period setting. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006
A simple approach for optimum channel reservation for hand‐over calls in cellular systems
Authors: Laith Mohamed , Bakry Saad Haj , Alheraish Abdulmohsen
Published: March 2006

In cellular mobile communication systems, while an active subscriber is moving from one cell to another, the service of his call needs to be handed over to the base station of the new cell. In such a case, cutting the service, due to all channels being busy at the new base station, would be more annoying to subscribers than normal congestion at the first initiation of calls. This paper is concerned with providing a simple approach for choosing the optimum set of channels that need to be reserved for hand‐over calls, while maintaining an acceptable overall system performance. The approach evaluates channel reservation at the cell level, taking into account the offered traffic, that is both the newly initiated original traffic and the hand‐over traffic. The approach produces a simple mathematical solution based on Erlang‐B formula. It uses the concept of ‘Combined Failure Rate’ to evaluate the required reservation. The approach is supported by a simulation study that verifies its validity. Applications of the approach to illustrate its use are also presented. Copyright © 2006 John Wiley & Sons, Ltd.
A tutorial on using genetic algorithms for the design of network topology
Authors: Al‐Bassam Bassam , Alheraish Abdulmohsen , Bakry Saad Haj
Published: March 2006

The design of network topology is an important part of network design, since network topology is directly associated with network operational behavior, capacity, reliability, and cost. This paper is a tutorial paper concerned with illustrating how the optimization capabilities of genetic algorithms can be used to design suitable network topologies considering basic topology problems. Simple genetic algorithms have been developed for the topology problem of mesh networks, considering single node and single link failure tolerance. The algorithms are based on criteria of two important measures: minimizing the length of communication links; and minimizing traffic flow through these links for given traffic loads. The first measure contributes to minimizing the cost of cabling, while the second measure contributes to minimizing the cost of link capacity. The work provides a useful approach and tools to network students and professionals concerned with the topology design of backbone networks. The developed software is made available on the Internet. Copyright © 2006 John Wiley & Sons, Ltd.
Mitochondrial clustering at the vertebrate neuromuscular junction during presynaptic differentiation
Authors: Lee Chi Wai , Peng H. Benjamin
Published: March 2006

During vertebrate neuromuscular junction (NMJ) development, presynaptic motor axons differentiate into nerve termini enriched in synaptic vesicles (SVs). At the nerve terminal, mitochondria are also concentrated, but how mitochondria become localized at these specialized domains is poorly understood. This process was studied in cultured Xenopus spinal neurons with mitochondrion‐specific probe MitoTracker and SV markers. In nerve‐muscle cocultures, mitochondria were concentrated stably at sites where neurites and muscle cells formed NMJs, and mitochondria coclustered with SVs where neurites were focally stimulated by beads coated with growth factors. Labeling with a mitochondrial membrane potential‐dependent probe JC‐1 revealed that these synaptic mitochondria were with higher membrane potential than the extrasynaptic ones. At early stages of bead‐stimulation, actin‐based protrusions and microtubule fragmentation were observed in neurites at bead contact sites, suggesting the involvement of cytoskeletal dynamics and rearrangement during presynaptic differentiation. Treating the cultures with an actin polymerization blocker, latrunculin A (Ltn A), almost completely abolished the formation of actin‐based protrusions and partially inhibited bead‐induced mitochondrial and SV clustering, whereas the microtubule disrupting agent nocodazole was ineffective in inhibiting the clustering of mitochondria and SVs. Lastly, in contrast to Ltn A, which blocked bead‐induced clustering of both mitochondria and SVs, the ser/thr phosphatase inhibitor okadaic acid inhibited SV clustering but not mitochondrial clustering. These results suggest that at developing NMJs, synaptogenic stimuli induce the clustering of mitochondria together with SVs at presynaptic terminals in an actin cytoskeleton‐dependent manner and involving different intracellular signaling molecules. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Maladaptation to mental stress mitigated by the adaptive immune system via depletion of naturally occurring regulatory CD4+CD25+ cells
Authors: Cohen Hagit , Ziv Yaniv , Cardon Michal , Kaplan Zeev , Matar Michael A. , Gidron Yori , Schwartz Michal , Kipnis Jonathan
Published: March 2006

Peripheral cellular immunity was recently shown to play a critical role in brain plasticity and performance. The antigenic specificity of the participating T cells, however, was not investigated, and nor was their relevance to psychological stress. Here we show, using a mouse model, that adaptive immunity mitigates maladaptation to the acute psychological stress known to trigger abnormal behaviors reminiscent of human post‐traumatic stress disorder. Assessment of behavioral adaptation (measured by the acoustic startle response and avoidance behavior) in mice after their exposure to predator odor revealed that maladaptation was several times more prevalent in T cell‐deficient mice than in their wild‐type counterparts. A single population of T cells reactive to central nervous system (CNS)‐associated self‐protein was sufficient to endow immune‐deficient mice with the ability to withstand the psychological stress. Naturally occurring CD4+CD25+ regulatory T cells were found to suppress this endogenous anti‐stress attribute. These findings suggest that T cells specific to abundantly expressed CNS antigens are responsible for brain tissue homeostasis and help the individual to cope with stressful life episodes. They might also point the way to development of immune‐based therapies for mental disorders, based either on up‐regulation of T cells that partially cross‐react with self‐antigens or on weakening of the activity of regulatory T cells. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Long‐term effects of a single exposure to immobilization: A C‐fos mRNA study of the response to the homotypic stressor in the rat brain
Authors: Vallès Astrid , Martí Octavi , Armario Antonio
Published: March 2006

A single exposure to a severe emotional stressor such as immobilization in wooden boards (IMO) causes long‐term (days to weeks) peripheral and central desensitization of the hypothalamic‐pituitary‐adrenal (HPA) response to the same (homotypic) stressor. However, the brain areas putatively involved in long‐term desensitization are unknown. In the present experiment, adult male rats were subjected to 2 h of IMO and, 1 or 4 weeks later, exposed again to 1 h IMO together with stress‐naive rats. C‐fos mRNA activation just after IMO and 1 h after the termination of IMO (post‐IMO) were evaluated by in situ hybridization. Whereas in most brain areas c‐fos mRNA induction caused by the last IMO session was similar in stress‐naive (controls) and previously immobilized rats, a few brain areas showed a reduced c‐fos mRNA response: ventral lateral septum (LSv), medial amygdala (MeA), parvocellular region of the paraventricular hypothalamic nucleus (pPVN), and locus coeruleus (LC). In contrast, an enhanced expression was observed in the medial division of the bed nucleus stria terminalis (BSTMv). The present work demonstrates that a previous experience with a stressor can induce changes in c‐fos mRNA expression in different brain areas in response to the homotypic stressor and suggests that LSv, MeA, and BSTMv may be important for providing signals to lower diencephalic (pPVN) and brainstem (LC) nuclei, which results in a lower physiological response to the homotypic stressor. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Proteomic analysis of the binding partners to enteropathogenic Escherichia coli virulence proteins expressed in Saccharomyces cerevisiae
Authors: Hardwidge Philip R. , Donohoe Sam , Aebersold Ruedi , Finlay B. Brett
Published: March 2006

Enteropathogenic Escherichia coli (EPEC) is an enteric human pathogen responsible for much worldwide morbidity and mortality. EPEC uses a type III secretion system to inject bacterial proteins into the cytosol of intestinal epithelial cells to cause diarrheal disease. We are interested in determining the host proteins to which EPEC translocator and effector proteins bind during infection. To facilitate protein enrichment, we created fusions between GST and EPEC virulence proteins, and expressed these fusions individually in Saccharomyces cerevisiae. The biology of S. cerevisiae is well understood and often employed as a model eukaryote to study the function of bacterial virulence factors. We isolated the yeast proteins that interact with individual EPEC proteins by affinity purifying against the GST tag. These complexes were subjected to ICAT combined with ESI‐MS/MS. Database searching of sequenced peptides provided a list of proteins that bound specifically to each EPEC virulence protein. The dataset suggests several potential mammalian targets of these proteins that may guide future experimentation.
Organosoluble and colorless fluorinated poly(ether imide)s from 1,2‐bis(3,4‐dicarboxyphenoxy)benzene dianhydride and trifluoromethyl‐substituted aromatic bis(ether amine)s
Authors: Chung Cheng‐Lin , Yang Chin‐Ping , Hsiao Sheng‐Huei
Published: March 2006

A series of novel aromatic poly(ether imide)s (PEI) containing ortho‐catenated phenylene rings and pendant trifluoromethyl group have been prepared from 1,2‐bis(3,4‐dicarboxyphenoxy)benzene dianhydride (1) with seven trifluoromethyl‐substituted aromatic bis(ether amine)s (2a‐g) via a conventional two‐stage process that included ring‐opening polyaddition to form the poly(amic acid)s followed by chemical imidization to the polyimides. These PEIs had inherent viscosities in the range of 0.45–1.17 dL/g that corresponded to weight–average and number–average molecular weights (by gel‐permeation chromatography) of 42,000–102,000 and 28,500–67,500, respectively. All the PEIs were readily soluble in many organic solvents and could be solution‐cast into transparent, flexible, and strong films. These films were essentially colorless; they had a very low yellowness index of 4.34–6.55 and an UV–vis absorption cut‐off wavelength at 361–370 nm. The PEIs exhibited moderate‐to‐high glass‐transition temperatures (Tg) in the range of 185–270 °C, softening temperatures (Ts) in the range of 184–275 °C, and 10% weight loss temperatures higher than 466 °C in nitrogen or in air. They also showed low moisture absorptions of 0.49–0.70% and low dielectric constants of 2.78–3.26 (measured at 10 kHz). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3092–3102, 2006
Copolymerization of poly(vinyl alcohol)‐graft‐poly(1,4‐dioxan‐2‐one) with designed molecular structure by a solid‐state polymerization method
Authors: Chen Si‐Chong , Wang Xiu‐Li , Yang Ke‐Ke , Wu Gang , Wang Yu‐Zhong
Published: March 2006

Poly(vinyl alcohol)‐graft‐poly(1,4‐dioxan‐2‐one) (PVA‐g‐PPDO) with designed molecular structure was synthesized by a solid‐state polymerization. The solid‐state copolymerization was preceded by a graft copolymerization of PDO initiated with PVA as a multifunctional initiator, and Sn (Oct)2 as a coininitiator/catalyst in a homogeneous molten state. The polymerization temperature was then decreased and the copolymerization was carried out in a solid state. The products prepared by solid‐state polymerization were characterized by 1H NMR and DSC, and were compared with those synthesized in the homogeneous molten state. The degree of polymerization (Dp), degree of substitution (Ds), yield and the average molecular weight of the graft copolymer with different molecular structure were calculated from the 1H NMR spectra. The results show that the crystallization process during the solid‐state polymerization may suppress the undesirable inter‐ or intramolecular side reactions, then resulting in a controlled molecular structure of PVA‐g‐PPDO. The results of DSC measurement show that the molecular structures determine the thermal behavior of the PVA‐g‐PPDO. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3083–3091, 2006
MO‐LCAO approach and ab initio computations
Authors: Re Giuseppe Del , Capobianco Amedeo
Published: March 2006

The physical reliability and foundations of the Hund–Hückel MO‐LCAO model, in which a molecular orbital (MO) is represented as a linear combination of atomic orbitals (LCAO), are examined in light of ab initio self‐consistent field (SCF) computations with bases of various sizes. It is shown that appropriate linear transformations of the basis make evident a substructure of the relevant ab initio matrices and vectors that justifies the physical assumptions on which the MO‐LCAO model rests. The main conceptual aspects, viz. hydrogen‐like atomic orbitals, hybrids, localized orbitals, give a coherent picture, and the numerical data show that the contributions to occupied orbital energies ignored in the MO‐LCAO model are actually small enough to justify their neglect in chemical structure studies. The numerical parameter values can therefore be read quantitatively in the ab inito results and the importance of the approximations made estimated. These conclusions have been drawn from studies on a variety of molecules with first‐ and second‐row atoms. The well‐established transferability of group properties in molecules suggests that they are generally valid. The claim that hybrids are method‐independent, and therefore features of chemical reality at the orbital level, is discussed due to its relevance for comparisons of the stability of chemical bonds based on overlap. Of course, further work on questions such as electronegativities and promotion is needed. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006