bluuebunny/crossref_metadata_2025 huggingface dataset:
Hb Baden: Structural and functional characterization
Authors: Abdulmalik Osheiza , Safo Martin K. , Seeholzer Steven H. , Asakura Toshio , Hasbrouck Nicole C. , Russell J. Eric
Published: July 2010

Hb Baden (β18Val→Met) is a rare variant hemoglobin that has never been functionally or clinically characterized. We describe a Hb Baden heterozygote who exhibits normal growth and development, as well as age‐ and gender‐appropriate hematological values. Surprisingly, in vitro analyses demonstrate that Hb Baden is relatively unstable and exhibits an abnormally high affinity for O2. These properties are likely to affect the physiologies of individuals who inherit the βBaden mutation in trans to a determinant for either a functionally relevant hemoglobinopathy or a mild thalassemia. The data also provide insights into the function of the A‐helix/AB‐segment of β globin, supporting a structural model in which this poorly understood region serves as a scaffold that fixes the positions of other helices that directly impact β‐globin function. Am. J. Hematol., 2010. © 2010 Wiley‐Liss, Inc.
Bio‐MOFs: Metall‐organische Gerüste für biologische und medizinische Anwendungen
Authors: McKinlay Alistair C. , Morris Russell E. , Horcajada Patricia , Férey Gérard , Gref Ruxandra , Couvreur Patrick , Serre Christian
Published: July 2010

Metall‐organische Gerüste bieten als eine Klasse von hochgradig porösen Materialien vielfältige Möglichkeiten für biologische und medizinische Anwendungen. Durch die große Bandbreite an chemischen Zusammensetzungen sind toxikologisch zulässige Rezepturen realisierbar, und durch die hohe Funktionalität der MOFs eröffnen sich Anwendungsmöglichkeiten in Bildgebungsverfahren und als Transporter für therapeutische Wirkstoffe. Die Herausforderungen auf diesem Gebiet bestehen nicht nur in der Entwicklung von neuen Feststoffen, sondern auch in der Verbesserung der Rezeptur und der Verarbeitung der Materialien. Hierzu gehören auch die Feineinstellung der Morphologie der Gerüste und die Modifizierung ihrer Oberflächen im Hinblick auf die angestrebten Anwendungen.
Abscheidung von Kohlendioxid: Perspektiven für neue Materialien
Authors: D'Alessandro Deanna M. , Smit Berend , Long Jeffrey R.
Published: July 2010

Der stark ansteigende Kohlendioxidgehalt in der Atmosphäre ist eines der drängendsten Umweltprobleme unserer Zeit. Eine Option zur Verringerung anthropogener CO2‐Emissionen ist die Abscheidung und Speicherung von Kohlendioxid (Carbon Capture and Storage, CCS) an Punktquellen wie Kraftwerken. Durch diese Sequestrierung steigt allerdings der Energiebedarf der Kraftwerke um 25–40 %. Wir berichten hier über die Technologien zur Abscheidung, die zur Verringerung der CO2‐Emissionen wahrscheinlich am besten geeignet sind. Dazu zählen Postcombustion‐Verfahren, bei denen die Abscheidung nach der Verbrennung stattfindet (vor allem die CO2/N2‐Separation), Precombustion‐Verfahren, bei denen CO2/H2‐Gemische eingesetzt werden, und die Konditionierung von Erdgas (CO2/CH4). Der Schlüssel zu deutlichen Fortschritten sind bessere Trennmittel zur Separation. Wir werden hier aktuelle Entwicklungen und neuartige Konzepte zur CO2‐Abtrennung durch Lösungsmittel‐Absorption, chemische und physikalische Adsorption und Membranen schildern und besonders auf Fortschritte auf dem wachsenden Gebiet Metall‐organischer Gerüste eingehen.
Deposition of hydroxyapatite and calcium oxalate dihydrate on a heat exchanger tube
Authors: East C. P. , Doherty W. O. S. , Fellows C. M. , Yu H.
Published: July 2010

Most studies on the characterisation of deposits on heat exchangers have been based on bulk analysis, neglecting the fine structural features and the compositional profiles of layered deposits. Attempts have been made to fully characterise a fouled stainless steel tube obtained from a quintuple Roberts evaporator of a sugar factory using X‐ray diffraction and scanning electron microscopy techniques. The deposit contains three layers at the bottom of the tube and two layers on the other sections and is composed of hydroxyapatite, calcium oxalate dihydrate and an amorphous material. The proportions of these phases varied along the tube height. Energy‐dispersive spectroscopy and XRD analysis on the surfaces of the outermost and innermost layers showed that hydroxyapatite was the major phase attached to the tube wall, while calcium oxalate dihydrate (with pits and voids) was the major phase on the juice side. Elemental mapping of the cross‐sections of the deposit revealed the presence of a mineral, Si‐Mg‐Al‐Fe‐O, which is probably a silicate mineral. Reasons for the defects in the oxalate crystal surfaces, the differences in the crystal size distribution from bottom to the top of the tube and the composite fouling process have been postulated. © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
IL‐13 upregulates GPIIb expression in megakaryocytic cell lines via STAT6
Authors: Shi Xiaoyu , Cai Wei , Zhou Ying , Zhang Xuejun , Xiong Lixia , Li Rong , Yu Xuemei , Li Wenlin
Published: July 2010

Interleukin 13 (IL‐13) is a key cytokine involved in the regulation of inflammatory, immune responses, and cell differentiation. The present study was to investigate the effect of IL‐13 on the expression of glycoprotein IIb (GPIIb), a megakaryocytic gene, in Dami cells (human megakaryoblastic leukemia cell line) and HEL cells (human erythroleukemic cell line, which has both erythroid and megakaryocytic markers). Furthermore, it addresses the mechanisms governing the regulation of GPIIb expression by IL‐13. The molecular responses of Dami cells and HEL cells to IL‐13 treatment were analyzed by RT‐PCR, Western blot, chromatin immunoprecipitation (ChIP) and flow cytometry analysis. We show that IL‐13Rα1 and IL‐4Rα are expressed in Dami cells and HEL cells. The expression of GPIIb was significantly upregulated at the mRNA and protein levels by treatment with IL‐13. Moreover, IL‐13 induced phosphorylation of signal transducer and activator of transcription 6(STAT6). By using a STAT6‐specific antibody and PCR primers designed to yield a product, which encompasses the STAT6 binding site of the GPIIb promoter, we have shown the binding of the IL‐13‐mediated activation of STAT6 to the promoter of GPIIb gene. These results broaden the involvement of IL‐13 into megakaryocyte differentiation by STAT6 pathway. Anat Rec 293:1470–1476, 2010. © 2010 Wiley‐Liss, Inc.
Degree of Mineralization at the Attachment of Lateral Pterygoid
Authors: Cioffi Iacopo , van Ruijven Leo J. , Michelotti Ambrosina , Langenbach Geerling E.J.
Published: July 2010

The degree of mineralization of bone (DMB) in the human mandibular condyle is heterogeneous, and differences in DMB have been related to variations in bone turnover caused by local strains. The lateral pterygoid muscle inserts at the anterior surface of the condyle. The aim of this study is to analyze the DMB at the attachment of this muscle as compared with a control region. It was hypothesized that, DMB at the attachment sites of lateral pterygoid muscles was lower than at the control regions, because of the larger number of loadings and subsequently higher remodeling rates. Also, as the human lateral pterygoid muscle is heterogeneous in its internal architecture, variations in DMB within the attachment sites were expected. 10 human mandibular condyles were scanned in a micro CT system. Within each condyle, two regions, that is, the pterygoid fovea and a posterior (control) region where no muscle was inserted, were selected to analyze regional differences in DMB. The attachment site was further divided into eight subregions to analyze subregional differences. At the pterygoid fovea the DMB of cortical bone was significantly lower than at the control region (p = 0.003) and increased in medio‐lateral direction. The results of this study could suggest an influence of the lateral pterygoid muscle on bone turnover at this site. Anat Rec 293:1387–1392, 2010. © 2010 Wiley‐Liss, Inc.
Biomarkers for the Prediction of Major Adverse Cardiovascular Events in Patients With Acute Coronary Syndrome
Authors: Zeng Qiang , Sun Xiao‐Nan , Ma Li‐Hua , Chen Lian , Wang Yu , Chen Chun , Ye Zai‐Yuan , Wu Zheng‐Hu , Li Yong‐Zhe , Xu Yang
Published: July 2010

The aim of this study is to find novel biomarkers for prognosis in patients with acute coronary syndrome (ACS). We enrolled 245 eligible patients with ACS and compared the protein expression between the two groups, with or without major adverse cardiovascular events (MACE). To determine biomarkers for prognosis, we performed mass spectrometry analysis. We found 10 proteins in the serum that can be used to classify ACS with or without MACE and specific protein peaks at m/z 1921.0, 2124.2, and 20887.3 that were increased in patients with MACE. These peaks reliably predict MACE occurrence in patients with ACS, in addition to the widely accepted markers troponin and brain natriuretic peptide precursor. The characteristic changes in the peaks at m/z 1921.09, 2124.2, and 20887.3 correlate with poor prognosis in ACS patients. These proteins could potentially be used as predictive biomarkers to evaluate patient prognosis. Anat Rec 293:1512–1518, 2010. © 2010 Wiley‐Liss, Inc.
Postnatal Development of Type II Collagen and Aggrecan mRNA Expression in a Rabbit Craniomandibular Joint
Authors: Feng Jianying , Gu Zhiyuan , Lin Xinping , Fan Yi
Published: July 2010

The aim of this study was to investigate the postnatal growth changes in the condyle and disc of the rabbit craniomandibular joint (CMJ). Forty‐eight rabbits from newborn to an age of 120 days were divided into eight groups, and chondrocytic differentiation and function were evaluated within the CMJ by in situ hybridization of type II collagen and aggrecan mRNA. The morphology of the posterior band and the bilaminar zone were similar in the newborn group and were composed primarily of mesenchymal cells and capillaries. After weaning, mastication loading induced the differentiation of mesenchymal cells, which was accompanied by structural differentiation between the posterior band and the bilaminar zone. Aggrecan first appeared in the posterior band of the disc at 30 days postnatally, when the rabbits began to masticate solid food. Type II collagen emerged in the disc at the age of 45 days. Both genes coexpressed in the deeper half of the proliferative layer, the whole hypertrophic layer, and the mineralized layer of the condylar cartilage and staining intensity increased with age. The coexpression of aggrecan and Type II collagen indicates the maturation of chondrocyte differentiation in the disc and condyle, which contributes to the biomechanical characteristics of the CMJ that resist functional stimulation. Anat Rec 293:1574–1580, 2010. © 2010 Wiley‐Liss, Inc.
Morphological Study on Microvasculature of Left Ventricular Wall in Infant and Adult Yaks
Authors: He Y.Y. , Yu S.J. , Cui Y. , Du P.
Published: July 2010

Observations on the microvasculature in the left ventricular wall of infant and adult yaks under light and scanning electron microscope (SEM) were presented. Moreover, the diameter of different microvasculature and the density of the capillaries in three layers of the ventricular myocardium were measured using Image Pro‐Plus 5.0. The results showed that the average luminal diameter of arterioles and precapillary arterioles in adult yak's hearts were, in most cases, larger than those in infant yaks. On the contrary, the diameters of the capillary in infant yak's hearts were larger than those in adult yaks. The density of capillary in the myocardium of adult yak's heart had significantly higher values (P<0.01) than those in infant yaks. Arterioles of yak's hearts were characterized by the bark‐like structure and the impressions of endothelial cell nuclei, and it always gave rise to capillary after three to four grades of embranchment. The outer surface of capillaries cast in infant yak's hearts was smooth, and no constrictions were found. This was different from adult yak that always had some constrictions. The capillary anastomosis of “H” and “Y” usually existed in the myocardium of both adult and infant yaks; however, those in infant yaks were not typical as in adult yaks in their shape. The peculiar arrangement of the venules in infant yak was a “baggy” or “bulgy” arrangement, while in the adult yak, they had a root‐like pattern. Our findings suggest that the patterns of microvasculature in yak's heart could be propitious to adapt better in their environment following their increase of age. Anat Rec 293:1519–1526, 2010. © 2010 Wiley‐Liss, Inc.
The Global Impact of Sutures Assessed in a Finite Element Model of a Macaque Cranium
Authors: Wang Qian , Smith Amanda L. , Strait David S. , Wright Barth W. , Richmond Brian G. , Grosse Ian R. , Byron Craig D. , Zapata Uriel
Published: July 2010

The biomechanical significance of cranial sutures in primates is an open question because their global impact is unclear, and their material properties are difficult to measure. In this study, eight suture‐bone functional units representing eight facial sutures were created in a finite element model of a monkey cranium. All the sutures were assumed to have identical isotropic linear elastic material behavior that varied in different modeling experiments, representing either fused or unfused sutures. The values of elastic moduli employed in these trials ranged over several orders of magnitude. Each model was evaluated under incisor, premolar, and molar biting conditions. Results demonstrate that skulls with unfused sutures permitted more deformations and experienced higher total strain energy. However, strain patterns remained relatively unaffected away from the suture sites, and bite reaction force was likewise barely affected. These findings suggest that suture elasticity does not substantially alter load paths through the macaque skull or its underlying rigid body kinematics. An implication is that, for the purposes of finite element analysis, omitting or fusing sutures is a reasonable modeling approximation for skulls with small suture volume fraction if the research objective is to observe general patterns of craniofacial biomechanics under static loading conditions. The manner in which suture morphology and ossification affect the mechanical integrity of skulls and their ontogeny and evolution awaits further investigation, and their viscoelastic properties call for dynamic simulations. Anat Rec 293:1477–1491, 2010. © 2010 Wiley‐Liss, Inc.
Computer simulation: The imaginary friend of auxin transport biology
Authors: Garnett Philip , Steinacher Arno , Stepney Susan , Clayton Richard , Leyser Ottoline
Published: July 2010

Regulated transport of the plant hormone auxin is central to many aspects of plant development. Directional transport, mediated by membrane transporters, produces patterns of auxin distribution in tissues that trigger developmental processes, such as vascular patterning or leaf formation. Experimentation has produced many, largely qualitative, data providing strong evidence for multiple feedback systems between auxin and its transport. However, the exact mechanisms concerned remain elusive and the experiments required to evaluate alternative hypotheses are challenging. Because of this, computational modelling now plays an important role in auxin transport research. Here we review some current approaches and underlying assumptions of computational auxin transport models. We focus on self‐organising models for polar auxin transport and on recent attempts to unify conflicting mechanistic explanations. In addition, we discuss in general how these computer simulations are proving to be increasingly effective in hypothesis generation and testing, and how simulation can be used to direct future experiments.

Editor's suggested further reading in BioEssays Local auxin production: a small contribution to a big field Abstract
Claudin‐5a in developing zebrafish brain barriers: another brick in the wall
Authors: Abdelilah‐Seyfried Salim
Published: July 2010

Claudins serve essential roles in regulating paracellular permeability properties within occluding junctions. Recent studies have begun to elucidate developmental roles of claudins within immature tissues. This work has uncovered an involvement of several claudins in determining tight junction properties that have an effect on embryonic morphogenesis and physiology. During zebrafish brain morphogenesis, Claudin‐5a determines the paracellular permeability of tight junctions within a transient neuroepithelial‐ventricular barrier that maintains the hydrostatic fluid pressure required for brain ventricular lumen expansion. However, the roles of Claudins in development may well extend beyond being mere junctional components. Several post‐translational modifications of Claudins have been characterized that indicate a direct regulation by developmental signals. This review focuses on the involvement of Claudin‐5a in cerebral barrier formation in the zebrafish embryo and includes some speculations about possible modes of regulation.
In‐line analysis of a fluid bed pellet coating process using a combination of near infrared and Raman spectroscopy
Authors: Bogomolov Andrey , Engler Maximiliane , Melichar Michael , Wigmore Anthony
Published: July 2010

Near infrared (NIR) and Raman spectroscopic analyzers applied through an immersion Lighthouse Probe (LHP) were used for simultaneous in‐line monitoring of a fluid bed pellet coating process. Multivariate curve resolution analysis of data, collected from four pilot‐scale batches, has shown that the two techniques deliver complementary information about the process and their combination may be synergistic. This data analysis enabled a much better understanding of some of the process observations and also gave some interesting insights into the best way to use the techniques themselves.

PLS regression analysis of the product moisture and the quantity of coating material sprayed was performed using NIR and Raman data blocks both separately and in combination. The performance of method combination compared to individual techniques is analyzed and discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Chiral Transformation in Protonated and Deprotonated Adipic Acids through Multistep Internal Proton Transfer
Authors: Min Seung Kyu , Park Mina , Singh N. Jiten , Lee Han Myoung , Lee Eun Cheol , Kim Kwang S. , Lagutschenkov Anita , Niedner‐Schatteburg Gereon
Published: July 2010

Protonated and deprotonated adipic acids (PAA: HOOC(CH2)4COOH2+ and DAA: HOOC(CH2)4COO−) have a charged hydrogen bond under the influence of steric constraint due to the molecular skeleton of a circular ring. Despite the similarity between PAA and DAA, it is surprising that the lowest energy structure of PAA is predicted to have (H2O⋅⋅⋅H⋅⋅⋅OH2)+ Zundel‐like symmetric hydrogen bonding, whereas that of DAA has H3O+ Eigen‐like asymmetric hydrogen bonding. The energy profiles show that direct proton transfer between mirror image structures is unfavorable. Instead, the chiral transformation is possible by subsequent backbone twistings through stepwise proton transfer along multistep intermediate structures, which are Zundel‐like ions for PAA and Eigen‐like ions for DAA. This type of chiral transformation by multistep intramolecular proton transfers is unprecedented. Several prominent OH⋅⋅⋅O short hydrogen‐bond stretching peaks are predicted in the range of 1000–1700 cm−1 in the Car–Parrinello molecular dynamics (CPMD) simulations, which show distinctive signatures different from ordinary hydrogen‐bond peaks. The OHO stretching peaks in the range of 1800–2700 cm−1 become insignificant above around 150 K and are almost washed out at about 300 K.
Insights into the Dynamics and Molecular Recognition Features of Glycopeptides by Protein Receptors: The 3D Solution Structure of Hevein Bound to the Trisaccharide Core of N‐Glycoproteins
Authors: Hernández‐Gay José Juan , Ardá Ana , Eller Steffen , Mezzato Stefano , Leeflang Bas R. , Unverzagt Carlo , Cañada F. Javier , Jiménez‐Barbero Jesús
Published: July 2010

Protein‐carbohydrate interactions are at the heart of a variety of essential molecular recognition events. Hevein, a model lectin related to the superantigen family, recognizes the trisaccharide core of N‐glycoproteins (1). A combined approach of NMR spectroscopy and molecular modeling has permitted us to demonstrate that an Asn‐linked Man(GlcNAc)2 (2) is bound with even higher affinity than (GlcNAc)3. The molecular recognition process entails conformational selection of only one of the possibilities existing for chitooligosaccharides. The deduced 3D structure of the hevein/2 complex permits the extension of polypeptide chains from the Asn moiety of 2, as well as glycosylation at Man O‐3 and Man O‐6 of the terminal sugar. Given the ubiquity of the Man(GlcNAc)2 core in all mammalian N‐glycoproteins, the basic recognition mode presented herein might be extended to a variety of systems with biomedical importance.
Optimierung der Herstellung von Biotensiden auf Basis nachwachsender Rohstoffe
Authors: Weber A. , Hoffmann A. , Górak A.
Published: July 2010

Ein Konzept zur Prozessentwicklung und ‐optimierung von biotechnologischen Produkten wurde am Beispiel der Herstellung von Sophoroselipiden entwickelt. Neben der mikrobiellen Herstellung mit produktionsintegrierter Produktabtrennung mittels Sedimentation wurde in dieser Arbeit die Extraktion im Rahmen der Grundoperationenauswahl als Aufreinigungsoption experimentell untersucht.
Verweilzeitverkürzung bei der Biogasentstehung durch Zerkleinerung von lignocellulosehaltigen Substraten
Authors: Haeffner B. , Nied C. , Voigt J. , Sommer K.
Published: July 2010

Der anaerobe Abbau von organischen Substraten zu Kohlendioxid und Methan ist ein mikrobiell katalysierter Prozess. Die einstufige Biogasgewinnung ist in der Landwirtschaft und in der Klärschlammaufbereitung weit verbreitet. Es findet eine Grobzerkleinerung statt, die nicht der Optimierung der Verweilzeitverkürzung dient, sondern das Verstopfen der Ventile und Pumpen verhindern soll. Ziel war es, den Einfluss der Partikelgröße auf den Biogasertrag festzustellen und die Zerkleinerung zu optimieren. Mit feinstzerkleinerten Trebersuspensionen als Substrat für die anaerobe Fermentation konnte bei stabilen Prozessbedingungen eine kürzere hydraulischer Verweilzeit, ein höherer Abbaugrad und ein höherer Methangehalt des Biogases erreicht werden.
Electrodialytic Defluoridation of Brackish Water: Effect of Process Parameters and Water Characteristics
Authors: Ben Sik Ali Mourad , Hamrouni Béchir , Dhahbi Mahmoud
Published: July 2010

The aim of this work is to study the removal of fluoride from brackish polluted water using electrodialysis. The influence of several parameters such as flow rate, initial feed concentration, co‐existing ions, and initial pH on process efficiency were studied. This efficiency is evaluated by the removal rate, demineralization rate, and power consumption. The defluoridation process showed to be independent of pH of feed solution. Although the remained studied parameters plays a significant role on the defluoridation efficiency and mainly on the specific power consumption. The defluoridation of a contaminated real water sample was investigated so as to improve the efficiency of the process. The fluoride concentration could be reduced from 2.9 to 0.4 mg L−1 which was lower than World Health Organization (WHO) standard (1.5 mg L−1). Moreover the concentrations of different species in the obtained treated water are below the amounts recommended by WHO for drinking water.
Novel Peptidyl Aryl Vinyl Sulfones as Highly Potent and Selective Inhibitors of Cathepsins L and B
Authors: Mendieta Laura , Picó Anna , Tarragó Teresa , Teixidó Meritxell , Castillo Marcos , Rafecas Llorenç , Moyano Albert , Giralt Ernest
Published: July 2010

Herein we present the design, synthesis, and evaluation of a structurally novel library of 20 peptidyl 3‐aryl vinyl sulfones as inhibitors of cathepsins L and B. The building blocks, described here for the first time, were synthesized in a highly efficient and enantioselective manner, starting from 3‐aryl‐substituted allyl alcohols. The corresponding vinyl sulfones were prepared by a new approach, based on a combination of solid‐phase peptide synthesis using the Fmoc/tBu strategy, followed by solution‐phase coupling to the corresponding (R)‐3‐amino‐3‐aryl vinyl sulfones as trifluoroacetate salts. The inhibitory activity of the resulting compounds against cathepsins L and B was evaluated, and the compound exhibiting the best activity was selected for enzymatic characterization. Finally, docking studies were performed in order to identify key structural features of the aryl substituent.
Limited resection followed by intraoperative seed implantation is comparable to stereotactic body radiotherapy for solitary lung cancer
Authors: Parashar Bhupesh , Patel Priti , Monni Stefano , Singh Prabhsimranjot , Sood Nikki , Trichter Samuel , Sabbas Albert , Wernicke A. Gabriella , Nori Dattatreyudu , Chao K. S. Clifford
Published: July 2010

BACKGROUND:

The objective of this study was to compare the outcomes of patients who underwent wedge resection plus intraoperative brachytherapy versus patients who received stereotactic body radiotherapy (SBRT) for single malignant lung nodules.

METHODS:

A retrospective chart review included 55 patients who were treated for single lung nodules, and 47 of those patients who had adequate information were chosen for the current analysis. Twenty‐five patients with single malignant lung nodules received SBRT. Twenty‐two patients underwent limited surgical resection plus radioactive seed implantation for solitary malignant lung nodules.

RESULTS:

Univariate statistical analysis demonstrated a significance difference only for age in the 2 groups: The mean age in the radioactive seed group (66.6 years) was statistically significantly different from the mean of the age in the SBRT group (75.9 years; 2‐sided P = .04). No significant differences were observed between the 2 groups in terms of local control, distant metastasis, survival, or toxicity.

CONCLUSIONS:

The current results demonstrated comparable efficacy in outcome and toxicity between surgical resection with radioactive seed implantation and SBRT for the treatment of single malignant lung nodules in patients who were not candidates for lobectomy/pneumonectomy. Cancer 2010. © 2010 American Cancer Society.
An access method using fixed backoff for wireless LANs
Authors: Nakamura Kazutoyo , Satake Shinsuke , Inai Hiroshi
Published: July 2010

In a wireless LAN, since two or more terminals randomly access a signal channel, frame collisions might occur. Under the standard IEEE 802.11 protocol, to avoid collisions, each terminal sets a random backoff before frame transmission. Although this measure avoids collisions, it results in useless standby duration and low throughput. To solve that problem, this paper proposes a media access method which has a fixed backoff after a successful transmission. It is shown by simulation that the proposed method reduces frame collisions and improves throughput. Furthermore, our method reduces the frame loss probability and the file transfer delay. 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(3): 30–39, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.21044
Impedimetric Aptasensors Based on Carbon Nanotubes – Poly(methylene blue) Composite
Authors: Porfireva Anna V. , Evtugyn Gennady A. , Ivanov Alexey N. , Hianik Tibor
Published: July 2010

The effect of aptamer structure and immobilization platform on the efficiency of thrombin binding and its detection using electrochemical impedance spectroscopy (EIS) characteristics was investigated with aptasensors based on glassy carbon electrodes covered with multiwalled carbon nanotubes (MWNTs). Aptamers with one or two binding sequences GGTTGGTGTGGTTGG specific for thrombin and poly(dA) and poly(dT) tags able to form dimeric products (aptabodies) were used to establish significance of steric and electrostatic factors in aptasensor performance. We have shown that electropolymerization of methylene blue onto MWNTs significantly improved electrochemical characteristics and sensitivity of thrombin detection against bare MWNTs. Charge transfer resistance and capacitance of the surface layer were measured in the presence of redox probe [Fe(CN)6]3−/4−. Aptasensors make it possible to detect thrombin in the concentration range 1 nM–1 µM with the limit of detection of 0.7 nM (monitoring resistance changes) and 0.5 nM (capacitance changes), respectively.
Differential Pulse Anodic Stripping Voltammetric Simultaneous Determination of Copper(II) and Silver(I) with Bis(2‐hydroxyacetophenone) Butane‐2,3‐dihydrazone Modified Carbon Paste Electrodes
Authors: Gholivand M. B. , Parvin M. H.
Published: July 2010

The behavior of a modified carbon paste electrode (CPE) for simultaneous determination of copper(II) and silver(I) by anodic adsorptive stripping voltammetry (ASV) was studied. The electrode was built incorporating the bis(2‐hydroxyacetophenone) butane‐2,3‐dihydrazone (BHAB) as a complexing agent to a Nujol‐graphite base paste. The resulting electrode demonstrated linear responses over the range of Cu(II) and Ag(I) concentrations 0.1–20 and 0.01–2.0 µM respectively. The relative standard deviation (RSD) for the determination of 5.0 µM of both metal ions were 2.9 and 3.1 % for Cu(II) and Ag(I), respectively. The method has been applied to the analysis of copper in wheat and barley seed samples and silver in developed radiological film.
Voltammetry of Os(VI)‐Modified Polysaccharides
Authors: Trefulka Mojmír , Paleček Emil
Published: July 2010

Polysaccharides (PSs), such as dextran, yeast mannan, starch and amylose, were modified with complexes of six‐valent osmium with nitrogen ligands [Os(VI)L] and voltammetric behavior of PS‐Os(VI)L adducts was studied at mercury and carbon electrodes. Using Os(VI)temed as a modification agent and adsorptive transfer stripping (ex situ) method it was possible to determine PSs at submicromolar concentrations directly in the reaction mixture in an excess of monomeric glucose or sucrose both at Hg and carbon electrodes. Conventional (in situ) PS determination in the reaction mixture was possible only with mercury electrodes. The above methods have great potentiality in biological research.
Substantial Influence of Temperature on Anchoring of Gold‐Nanoparticle Monolayer for Performance of DNA Biosensors
Authors: Nowicka Anna M. , Kowalczyk Agata , Donten Mikolaj , Leech Dónal , Hepel Maria , Stojek Zbigniew
Published: July 2010

This paper presents a way of modification of crystalline gold surface with a high quality layer of gold nanoparticles (Au NPs) via self‐assembled dithiol. The application of additional Au NPs monolayer prepared at various temperatures was tested with three types of biosensors previously described in the literature. The examined DNA biosensors differed by the detection method and the way of the immobilization of DNA probe at the modified gold electrode surface. For the immobilization of DNA probe in the sensing layer either the formation of SAM or the affinity binding (biotin – sterptavidin) or covalent attachment were used. The necessary condition of successful preparation of a perfect such monolayer is the preparation temperature of 4 °C. The preparation of Au NPs layers at higher than 4 °C temperatures leads to poor repeatability and unsatisfactory precision of the measurements. The application of the perfect Au monolayer lowers the detection limit (circa by 10 to 100 times) for all tested DNA biosensors.
Sonographic assessment of cervical lymphadenopathy: Role of high‐resolution and color Doppler imaging
Authors: Gupta Abhishek , Rahman Khaliqur , Shahid Mohammad , Kumar Abhishek , Qaseem S. M. Danish , Hassan S. Abrar , Siddiqui Farhan Asif
Published: July 2010

Background.

The objective of this article was to study the role of high frequency ultrasound and color Doppler imaging in the diagnostic evaluation of patients with cervical lymphadenopathy.

Methods.

The present study was carried out over a period of 18 months and included 64 patients of different age groups presenting with cervical lymphadenopathy. Comprehensive sonographic examination of the neck for cervical lymph nodes was performed using the LOGIQ 500 ultrasound machine (GE Wipro Proseries). The scanning was performed with the patient in the supine position, and with the neck hyperextended using a pad or pillow under the shoulders in order to provide optimum exposure of the neck. The parameters considered in this study included: site, mean long axis (L), mean short axis (S), shape index (S/L), echotexture and homogenicity, margins, ancillary features like calcification, necrosis, posterior enhancement, matting and surrounding tissue changes, vascular pattern, and mean arterial resistive index (RI). These findings were correlated with fine‐needle aspiration cytology and excisional biopsy. The nodes were classified as reactive, lymphomatous, and metastatic. The results were subjected to statistical analysis using SPSS software. A p value of <.05 was considered to be significant.

Results.

The results showed that malignant lymph nodes, especially metastatic nodes, are mostly accompanied with rounded shape, homogenous echotexture, peripheral vascularity, and significantly high RI. Among these sonographic findings, nodal shape (S/L ratio) and RI were more accurate for differentiating benign from malignant lymph nodes. Most of the malignant nodes had well‐defined borders. Calcification, necrosis, posterior enhancement, matting, and hilar flow patterns were characteristically found in tubercular lymphadenitis. A combined ultrasound‐guided and fine‐needle aspiration (FNA) diagnosis had a high sensitivity (95.4%) and specificity (92.3) as compared with situations in which they were used alone.

Conclusion.

Sonographic findings have a high accuracy in differentiating benign from malignant cervical lymph nodes. An ultrasound scan can be used as the first‐line imaging tool in the diagnostic evaluation of cervical lymphadenopathy, especially in developing countries like India due to its ease, noninvasiveness, reproducibility, and cost effectiveness. It can also be used as an imaging tool for the guided aspirations. However, because of some overlapping in sonographic appearances of benign and malignant nodes, this modality may not have definite diagnostic values. But when combined with FNA, it has a very high sensitivity and specificity. © 2010 Wiley Periodicals, Inc. Head Neck, 2010
Central compartment dissection in laryngeal cancer
Authors: Medina Jesus E. , Ferlito Alfio , Robbins K. Thomas , Silver Carl E. , Rodrigo Juan P. , de Bree Remco , Rinaldo Alessandra , Elsheikh Mohamed N. , Weber Randal S. , Werner Jochen A.
Published: July 2010

We report here a review of the literature intended to clarify the nomenclature and boundaries of the nodes in the “central compartment” of the neck, the frequency with which tumors from the different laryngeal sites metastasize to these nodes, and the indications for central compartment node dissection in the treatment of cancers of the larynx. From this review, we conclude that, until consensus is reached about grouping of the lymph nodes in this area, it is best to refer to these nodes by their anatomic location, ie, prelaryngeal, pretracheal, or paratracheal lymph nodes. It is also advisable to describe dissection of these nodes as selective neck dissection (SND) with an annotation about the specific lymph node groups removed. Metastases in prelaryngeal and paratracheal lymph nodes in patients with squamous cell carcinoma of the larynx are associated with increased tumor recurrence, more frequent metastases in lymph nodes of the lateral compartment of the neck, and decreased survival. If untreated, they may lead to the development of peristomal recurrence. Therefore, elective treatment of level VI nodes is recommended in patients with squamous cell carcinomas of the subglottic region, advanced glottis carcinomas with subglottic extension, and in certain advanced carcinomas of the supraglottic region. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
Prognostic significance of nuclear pSTAT3 in oral cancer
Authors: Macha Muzafar A. , Matta Ajay , Kaur Jatinder , Chauhan S. S. , Thakar Alok , Shukla Nootan K. , Gupta Siddhartha Datta , Ralhan Ranju
Published: July 2010

Background

Aberrant nuclear accumulation of proteins influences tumor development and may predict biologic aggressiveness and disease prognosis. This study determined the prognostic significance of pSTAT3 (phosphorylayed signal transducer and activator of transcription 3) in oral squamous cell carcinomas (OSCCs).

Methods and Results

Using immunohistochemistry, a significant increase in nuclear accumulation of pSTAT3 was observed in 49 of 90 leukoplakias (54.4%) and 63/94 OSCCs (67%) (ptrend < .001). Increased pSTAT3 was associated with tumor stage (p = .01), nodal metastasis (p = .0018), and tobacco consumption (p = .004). Kaplan–Meier analysis demonstrated that OSCC with increased nuclear pSTAT3 showed significantly reduced disease‐free survival (13 months), compared with the patients with no nuclear pSTAT3 expression (64 months, p = .019). Cox regression analysis revealed nuclear pSTAT3 as the most significant predictor of poor prognosis (p = .024, hazard ratio [HR] = 2.7).

Conclusions

Increased nuclear accumulation of pSTAT3 occurs in early premalignant stages and is a marker for poor prognosis of OSCC. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
Bridging gold: B‐Au‐B three‐center‐two‐electron bonds in electron‐deficient B2Aun−/0 (n = 1, 3, 5) and mixed analogues
Authors: Yao Wen‐Zhi , Li Da‐Zhi , Li Si‐Dian
Published: July 2010

A systematic density functional theory and wave function theory investigation on the geometrical and electronic structures of the electron‐deficient diboron aurides B2Au (n = 1, 3, 5) and their mixed analogues B2HmAu (m + n = 3, 5) has been performed in this work. Ab initio theoretical evidences strongly suggest that bridging gold atoms exist in the ground states of C2v B2Au−(1A1), C2 B2Au(1A), C2v B2Au3(2B1), C2v B2Au(1A1), and Cs B2Au5(2A″), which all prove to possess a BAuB three‐center‐two‐electron (3c‐2e) bond. For B2HmAu (m + n = 3, 5) mixed anions, bridging BAuB units appear to be favored in energy over bridging BHB, as demonstrated by the fact that the Au‐bridged C2v B2H2Au− (1A1), Cs B2HAu (1A′), and C1 B2HAu (1A) lie clearly lower than their H‐bridged counterparts Cs B2H2Au− (1A′), C2 B2HAu (1A), and C2v B2HAu (1A1), respectively. Orbital analyses indicate that Au 6s makes about 92–96% contribution to the Au‐based orbitals in these B‐Au‐B 3c‐2e interactions, whereas Au 5d contributes 8–4%. The adiabatic and vertical detachment energies of the concerned anions have been calculated to facilitate their future experimental characterizations. The results obtained in this work establish an interesting 3c‐2e bonding model (BAuB) for electron‐deficient systems in which Au 6s plays a major role with non‐negligible contribution from Au 5d. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011
Geometrically associative yet electronically dissociative character in the transition state of enzymatic reversible phosphorylation
Authors: Re Suyong , Imai Takashi , Jung Jaewoon , Ten‐No Seiichiro , Sugita Yuji
Published: July 2010

Reversible phosphorylation of proteins is a post‐translational modification that regulates diverse biological processes. The molecular mechanism underlying phosphoryl transfer catalyzed by enzymes remains a subject of active debate. In particular, the nature of transition state (TS), whether it has an associative or dissociative character, has been one of the most controversial issues. Structural evidence supports associative TS, whereas physical organic studies point to a dissociative character. Here we perform hybrid quantum mechanics/molecular mechanics simulations for the reversible phosphorylation of phosphoserine phosphatase (PSP) to study the nature of the TS. Both phosphorylation and dephosphorylation reactions are investigated based on the two‐dimensional energy surfaces along phosphoryl and proton transfer coordinates. The structures of the active site at TS in both reactions reveal compact geometries, consistent with crystal structures of PSP with phosphate analogues. However, the electron density of the phosphoryl group in both TS structures slightly decreases compared with that in the reactant states. These findings suggest that the TS of PSP has a geometrically associative yet electronically dissociative character and strongly depends on proton transfer being coupled with phosphoryl transfer. Structure and literature database, which searches on phosphotransferases, suggest that such a hybrid TS is consistent with many structures and physical organic studies and likely holds for most enzymes catalyzing phosphoryl transfer. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011
Heisenberg behavior of some carbon‐beryllium compounds: How well truncated‐CI approaches work
Authors: Calzado Carmen J. , Monari A. , Evangelisti S.
Published: July 2010

This works tries to establish the performance of truncated CI calculations on the evaluation of magnetic coupling parameters with respect to available FCI estimates on a set of carbon‐beryllium clusters. First‐, second‐ and third‐neighbor magnetic coupling constants have been evaluated and many body effective parameters as the cyclic terms. They result from the fitting of the low‐lying states to the eigenvalues of an extended Heisenberg Hamiltonian, involving not only two‐body isotropic terms but also cyclic terms. SDCI and DDCI calculations have been carried out and their performance compared with FCI ones. The impact of the basis set choice and size‐consistency errors have been explored. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011
Noise analysis for 3‐point chemical shift‐based water‐fat separation with spectral modeling of fat
Authors: Chebrolu Venkata V. , Yu Huanzhou , Pineda Angel R. , McKenzie Charles A. , Brittain Jean H. , Reeder Scott B.
Published: July 2010

Purpose:

To model the theoretical signal‐to‐noise ratio (SNR) behavior of 3‐point chemical shift‐based water‐fat separation, using spectral modeling of fat, with experimental validation for spin‐echo and gradient‐echo imaging. The echo combination that achieves the best SNR performance for a given spectral model of fat was also investigated.

Materials and Methods:

Cramér‐Rao bound analysis was used to calculate the best possible SNR performance for a given echo combination. Experimental validation in a fat‐water phantom was performed and compared with theory. In vivo scans were performed to compare fat separation with and with out spectral modeling of fat.

Results:

Theoretical SNR calculations for methods that include spectral modeling of fat agree closely with experimental SNR measurements. Spectral modeling of fat more accurately separates fat and water signals, with only a slight decrease in the SNR performance of the water‐only image, although with a relatively large decrease in the fat SNR performance.

Conclusion:

The optimal echo combination that provides the best SNR performance for water using spectral modeling of fat is very similar to previous optimizations that modeled fat as a single peak. Therefore, the optimal echo spacing commonly used for single fat peak models is adequate for most applications that use spectral modeling of fat. J. Magn. Reson. Imaging 2010;32:493–500. © 2010 Wiley‐Liss, Inc.
Edited MRS is sensitive to changes in lactate concentration during inspiratory hypoxia
Authors: Edden Richard A.E. , Harris Ashley D. , Murphy Kevin , Evans C. John , Saxena Neeraj , Hall Judith E. , Bailey Damian M. , Wise Richard G.
Published: July 2010

Purpose:

To demonstrate the application of Mescher‐Garwood (MEGA) point‐resolved spectroscopy sequence (PRESS) editing to the detection of lactate in the brain at 3T and to investigate changes in lactate concentration associated with inspiratory gas challenges.

Materials and Methods:

Edited lactate measurements were made in six healthy volunteers while the subjects breathed normoxic (21% O2), hypoxic (12% O2), and hyperoxic (40% O2) gas mixtures. Lactate concentration was quantified relative to the unsuppressed water signal from the same volume.

Results:

Lactate concentration was elevated in all subjects during hypoxia in a highly significant fashion (mean increase = 39%; P = 0.0003). There was no significant change seen in hyperoxia.

Conclusion:

MEGA‐PRESS editing at 3T is sufficiently sensitive to detect lactate in the healthy brain with good signal‐to‐noise ratio (SNR), and can be used to investigate changes in cerebral metabolism arising during inspiratory gas challenges. J. Magn. Reson. Imaging 2010;32:320–325. © 2010 Wiley‐Liss, Inc.
Evaluation of group homogeneity during acupuncture stimulation in fMRI studies
Authors: Sun Jinbo , Qin Wei , Dong Minghao , Yuan Kai , Liu Jixin , Liu Peng , Zhang Yi , von Deneen Karen M. , Tian Jie
Published: July 2010

Purpose:

To evaluate the extent of individual differences of functional MRI (fMRI) signal changes induced by acupuncture stimulation.

Materials and Methods:

Acupuncture at ST36 and checkerboard stimulation was applied to 16 subjects. We calculated the mean distance using beta values in a generalized linear model (GLM) analysis and employed it to study the group homogeneity by detecting the outliers.

Results:

A more significant individual difference was presented in acupuncture stimulation compared with visual stimulation through evaluation of the mean distance. From the group results, we found that the activations were more significant in the homogeneous group results. Combining the behavior and fMRI results, there was no direct correlation between deqi index and mean distance in acupuncture stimulation. The deqi index of the outlier was in the normal range and did not differ significantly from others.

Conclusion:

Traditional group results without removing outliers were not sensitive enough to detect the real acupuncture effect. We suggest that individual difference should be taken into consideration for future acupuncture studies. Also, group analysis paralleled with individual analysis is critical for a full understanding of acupuncture effects. J. Magn. Reson. Imaging 2010;32:298–305. © 2010 Wiley‐Liss, Inc.
Neurovascular changes measured by time‐of‐flight MR angiography in cholesterol‐fed rabbits with cortical amyloid β‐peptide accumulation
Authors: Lemieux Susan K. , Smith‐Bell Carrie A. , Wells Jered R , Ezerioha Nnadozie M. , Carpenter Jeffrey S. , Sparks D. Larry , Schreurs Bernard G.
Published: July 2010

Purpose:

To test the hypothesis that narrowing of cranial blood vessels in cholesterol‐fed rabbits is a function of the duration of the high cholesterol diet. Such neurovascular changes, caused by elevated serum cholesterol, are linked to stroke and Alzheimer's disease risk.

Materials and Methods:

Four groups of New Zealand White rabbits were studied. Six were fed a normal diet, 19 were fed a 2% cholesterol diet with 0.12 ppm copper in the drinking water for 8 weeks, 10 weeks, or 12 weeks. Time‐of‐flight (TOF) MR angiography (MRA) at 3 Tesla was used to measure arterial diameters in 11 vessels. Previously published data for amyloid β‐peptide (Aβ) accumulation in the brains measured postmortem were correlated to vessel diameters. Ventricular volumes of rabbits were measured on group‐averaged data.

Results:

Several vessel diameters decreased with cholesterol diet duration. The posterior communicating arteries showed the largest significant effect. Aβ accumulation was inversely correlated with arterial diameter. Ventricular volumes between the normal diet and 12 weeks cholesterol‐fed groups were not significantly different.

Conclusion:

Reduction in vessel diameter of medium‐sized vessels but not large vessels was measured in these hypercholesterolemic rabbits. The vessel diameter narrowing and cortical Aβ deposition occurred before measurable ventricular enlargement. J. Magn. Reson. Imaging 2010;32:306–314. © 2010 Wiley‐Liss, Inc.