bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of published recommendations on the management of penetrating abdominal injury
Authors: Clarke S C E , Stearns A T , Payne C , McKay A J
Published: December 2007

Background

In patients with penetrating abdominal injury (PAI), haemodynamic instability and peritonitis are indications for laparotomy, but it remains uncertain whether laparotomy is indicated for evisceration, retained foreign body and pneumoperitoneum. In 1989, a review of 107 patients with PAI revealed a 78·5 per cent laparotomy rate, with 35 per cent considered unnecessary. The aim of this study was to review current practice in the same hospitals.

Methods

A retrospective review included case notes from 224 patients with PAI presenting to three hospitals between 2001 and 2005.

Results

Some 206 patients (92·0 per cent) were male and the mean age was 30·5 years. Aetiologies were stabbing (96·4 per cent), impalement (2·7 per cent) and gunshot wound (0·9 per cent). Laparotomy was performed in 48 patients (21·4 per cent), and was positive in 33 and unnecessary or negative in 15. Haemodynamic instability and peritonitis were strong indicators of positive laparotomy; seven of 13 laparotomies for evisceration alone were negative, as were two of four for retained foreign bodies.

Conclusion

The laparotomy rate fell from 78·5 to 21·4 per cent over 25 years. The rate of unnecessary or negative laparotomy did not change. Isolated evisceration and retained foreign body remain relative indications.
The clinical anatomy of congenital portosystemic venous shunts
Authors: Stringer Mark D.
Published: December 2007

Congenital portosystemic venous shunts are rare. Their gross anatomy has not been well defined. Four different varieties of congenital portosystemic venous shunts are described in six children seen during a 10‐year period, focusing on the anatomy of the shunt as determined by imaging studies and surgery. A detailed review of the literature indicates that congenital portosystemic venous shunts are best classified as: extrahepatic or intrahepatic. Extrahepatic shunts may be further subdivided into portocaval shunts (type 1 end‐to‐side and type 2 side‐to‐side) and others. Intrahepatic shunts are due to an abnormal intrahepatic connection between the portal vein and hepatic vein/inferior vena cava or a persistent patent ductus venosus. Additional congenital anomalies, particularly cardiac malformations, may be associated with any type. Some congenital intrahepatic portosystemic venous shunts close spontaneously in infancy; all other congenital portosystemic venous shunts tend to remain patent. To a variable extent, depending largely on the volume and duration of the shunt, affected individuals are at risk of developing hepatic encephalopathy and/or an intrahepatic tumor. The key to understanding the pathogenesis of these shunts lies in the normal developmental mechanisms underlying the formation of the portal vein and inferior vena cava in the embryo. Clin. Anat. 21:147–157, 2008. © 2008 Wiley‐Liss, Inc.
Parallel Analysis of Two Analytes in Solutions or on Surfaces by Using a Bifunctional Aptamer: Applications for Biosensing and Logic Gate Operations
Authors: Elbaz Johann , Shlyahovsky Bella , Li Di , Willner Itamar
Published: December 2007

A bifunctional aptamer that includes two aptamer units for cocaine and adenosine 5′‐monophosphate (AMP) is blocked by a nucleic acid to form a hybrid structure with two duplex regions. The blocked bifunctional aptamer assembly is used as a functional structure for the simultaneous sensing of cocaine or AMP. The blocked bifunctional aptamer is dissociated by either of the two analytes, and the readout of the separation of the sensing structure is accomplished by a colorimetric detection, by a released DNAzyme, or by electronic means that use Faradaic impedance spectroscopy or field‐effect transistors. In one configuration, the blocked bifunctional aptamer structure is separated by the substrates cocaine or AMP, and the displaced blocker units act as a horseradish peroxidase‐mimicking DNAzyme that permits the colorimetric detection of the analytes. In the second system, the blocked bifunctional aptamer hybrid is associated with a Au electrode. The displacement of the aptamer by any of the substrates alters the interfacial electron transfer resistance at the electrode surface, thus providing an electronic signal for the sensing process. In the third configuration, the blocked aptamer hybrid is linked to the gate of a field‐effect transistor device. The separation of the complex by means of any of the analytes, cocaine, or AMP alters the gate potential, and this allows the electronic transduction of the sensing process by following the changes in the gate‐to‐source potentials. The different systems enable not only the simultaneous detection of the two analytes, but they provide a functional assembly that performs a logic gate “OR” operation.
The Role of the Conserved Threonine in P450BM3 Oxygen Activation: Substrate‐Determined Hydroxylation Activity of the Thr268Ala Mutant
Authors: Cryle Max J. , De Voss James J.
Published: December 2007

The hydroxylation activity of the Thr268Ala mutant of P450BM3 has been shown to occur to varying degrees with small alterations in the structure of a fatty‐acid substrate. Ten substrates were investigated, including straight chain, branched chain and cis‐cyclopropyl substituted fatty acids with a straight‐chain length that varied between 12 and 16 carbon atoms. The efficacy of the hydroxylation activity appeared to be governed by the chain length of the substrate. Substrates possessing 14 to 15 carbons afforded the highest levels of activity, which were comparable with the wild‐type enzyme. Outside of this window, straight‐chain fatty acids showed reduced activity over the other substrate types. These results provide a cautionary tale concerning the loss of ferryl activity in such cytochrome P450 threonine to alanine mutants, as the nature of the substrate can determine the extent to which hydroxylation chemistry is abolished.
H2O2/Nitrite‐Induced Post‐translational Modifications of Human Hemoglobin Determined by Mass Spectrometry: Redox Regulation of Tyrosine Nitration and 3‐Nitrotyrosine Reduction by Antioxidants
Authors: Chen Hauh‐Jyun Candy , Chang Chia‐Ming , Lin Wen‐Peng , Cheng Dar‐Long , Leong Mei‐I
Published: December 2007

Covalent modifications of proteins by endogenous reactive nitrogen oxide species lead to cytotoxic effects that are implicated in diseases associated with chronic infections and inflammation. Tyrosine nitration is a major post‐translational modification of proteins by reactive nitrogen oxide species. Recent studies suggest that nitrotyrosine is not a permanent protein modification. We previously demonstrated that lipoyl dehydrogenase is capable of converting 3‐nitrotyrosine into 3‐aminotyrosine in the presence of certain reducing agents. In this study, we compared the abilities of various hemoproteins, hemin, and the cobalt‐containing cofactor cyanocobalamin to mediate H2O2/nitrite‐dependent tyrosine nitration and found that these hemoproteins and metal‐containing cofactors also catalyzed the reduction of 3‐nitrotyrosine to various extents in the presence of thiol reducing agents or ascorbate. The H2O2/nitrite‐induced post‐translational modifications of human hemoglobin identified by nanoLC/nanospray ionization tandem mass spectrometric analysis of the tryptic digest include nitration of tyrosine and tryptophan, as well as oxidation of methionine and cysteine residues. Nitration of human hemoglobin by H2O2/nitrite was detected on Tyr24 and Tyr42 (α‐chain) and on Tyr130 and Trp15 (β‐chain) in the αβ‐dimer. Oxidation of methionine and cysteine residues was also observed. Furthermore, hemoglobin also catalyzed nitro reduction of 3‐nitrotyrosine to form 3‐aminotyrosine, at Tyr24 in the α‐chain peptide of human Hb in the presence of ascorbate. The enhanced peroxidase activity of nitrated hemoglobin can be reversed by the antioxidant ascorbate. These results suggest a possible in vivo pathway for hemoglobin contributing to denitration of nitrated proteins through redox regulation.
Supramolecular Gels Formed by Amphiphilic Low‐Molecular‐Weight Gelators of Nα,Nε‐Diacyl‐L‐Lysine Derivatives
Authors: Suzuki M. , Yumoto M. , Shirai H. , Hanabusa K.
Published: December 2007

Simple L‐lysine derivatives, Nα‐hexanoyl‐Nε‐lauroyl‐L‐lysine (1), its alkali metal salts (2–4), and two‐component compounds that consist of 1 with 2 to 4, were synthesized and their hydrogelation and organogelation properties were studied. Addition of hydrochloric acid to an aqueous solution of the alkali metal salt at room temperature produced a translucent hydrogel. This hydrogelation occurred as a result of a change in nanostructure from micelle‐like aggregates to nanofibers, which was induced by partial protonation of the carboxylate to form a carboxylic acid. On the other hand, two‐component low‐molecular‐weight gelators exhibited amphiphilic gelation behavior and functioned as not only hydrogelators, but also as organogelators. FTIR studies revealed that lateral ionic interactions between the carboxylate, alkali metal cation, carboxylic acid, and protons, in addition to hydrogen‐bonding and van der Waals interactions play a very important role in hydrogelation. Furthermore, it was found that the water‐insoluble carboxylic acid compound underwent a precipitation–dissolution transition with a thermally reversible sol–gel transition in the two‐component gelator systems.
A Pattern Recognition Based Fluorescence Quenching Assay for the Detection and Identification of Nitrated Explosive Analytes
Authors: Hughes Andrew D. , Glenn Ian C. , Patrick Andrew D. , Ellington Andrew , Anslyn Eric V.
Published: December 2007

Herein we report a differential array of micelle‐solubilized fluorophores for the detection and identification of small nitrated analytes, such as the explosives TNT, tetryl, RDX and HMX. The quenching ability of the analytes can be used to correlate their analyte identity, wherein the quenching patterns generated from the differential array are used in linear discriminant analysis (LDA). LDA results in a well‐clustered two‐dimensional plot, and a jack‐knife analysis of the data suggests that this system can be used to identify unknown samples of analyte with 96 % accuracy and with a detection limit of 19 μM.
The Calculation of Polar Surface Area from First Principles: An Application of Quantum Chemical Topology to Drug Design
Authors: Bytheway Ian , Darley Michael G. , Popelier Paul L. A.
Published: December 2007

The calculation of polar surface areas (PSA) from the electron density using quantum chemical topology (QCT) and a newly developed algorithm to determine isodensity surface areas is described. PSA values were calculated from the atomic partitioning of B3LYP/6‐311G* wavefunctions and the results described herein represent the first application of this new algorithm. PSA values were calculated for forty drugs and compared to the topological polar surface area (TPSA) and those calculated by the QikProp program. Oral bioavailabilities predicted from the QCT PSA values for a subset of twenty drugs (the Palm set) were similar to those predicted by the dynamic polar surface area (DPSA) and in general, are in agreement with the observed values. Overall, PSA values obtained from QCT were generally similar to the DPSA, TPSA, and QikProp values, though differences in fragment contributions were found, with nitrogen‐bearing functional groups showing the largest variation between methods. Differences between methods showed how the calculation of the PSA is dependent on the method used and, therefore, judicious application of the upper limits used in the prediction of oral bioavailability is warranted. These results also indicate that, because of the differences in the way PSA values are calculated, values from the different methods should not be used interchangeably.
Carbonic Anhydrase Inhibitors: Binding of Indanesulfonamides to the Human Isoform II
Authors: D'Ambrosio Katia , Masereel Bernard , Thiry Anne , Scozzafava Andrea , Supuran Claudiu T. , De Simone Giuseppina
Published: December 2007

Indanesulfonamides are interesting lead compounds for designing selective inhibitors of the different isoforms of the zinc enzyme Carbonic Anhydrase (CA). Herein, we report for the first time the X‐ray crystal structure of two such derivatives, namely indane‐5‐sulfonamide and indane‐2‐valproylamido‐5‐sulfonamide, in complex with the physiologically dominant human isoform II. The structural analysis reveals that, although these two inhibitors have quite similar chemical structures, the arrangement of their indane ring within the enzyme active site is significantly diverse. Thus, our findings suggest that the introduction of bulky substituents on the indane‐sulfonamide ring may alter the binding mode of this potent class of CA inhibitors, although retaining good inhibitory properties. Accordingly, the introduction of bulky tail moieties on the indane‐sulfonamide scaffold may represent a powerful strategy to induce a desired physicochemical property to an aromatic sulfonamide or to obtain inhibitors with diverse inhibition profiles and selectivity for various mammalian CAs.
Die Anwendung von numerischen Methoden zur Tragwerksanalyse von Baudenkmälern
Authors: Lourenço Paulo
Published: December 2007

Die Erhaltung und Sanierung von historischen Bauwerken stellen immer noch eine Herausforderung für die Praktiker dar, da gerade in den letzten Jahrzehnten beträchtliche Fortschritte und Erkenntnisse in der Forschung erzielt werden konnten, insbesondere in Bezug auf zerstörungsfreie Prüfverfahren, Erfassung der mechanischen Eigenschaften, Berechnungsmethoden zur realitätsnahen numerischen Untersuchung, sowie zu traditionellen als auch innovativen Baumaterialien und Techniken. In diesem Beitrag werden die Bedeutung der statisch‐konstruktiven Denkmalpflege und ihrer ingenieurtechnischen Aspekte erörtert und die Anwendung von modernen numerischen Berechnungsmethoden anhand von ausgewählten Fallstudien diskutiert. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nichtlineare Nachstellung von Mauerwerksversuchen am Beispiel von Zug‐ und Biege‐zugbeanspruchung
Authors: Jäger Wolfram , Hoffmann Jens , Schöps Peter
Published: December 2007

Die beiden aktuellen deutschen Bemessungsnormen für Mauerwerk enthalten für den Nachweis von Zugbeanspruchungen (Biegezug und zentrischer Zug jeweils parallel zu den Lagerfugen) sehr einfache und praktische Beziehungen, die innerhalb der Zugbruchkriterien den Einfluss der Lagerfugen vernachlässigen. In Versuchen wurde jedoch immer wieder ein derartiger Einfluss festgestellt. Mit Hilfe nichtlinearer numerischer Methoden lässt sich das Tragverhalten von Mauerwerk immer besser nachstellen und so können in Parameterstudien die Einflüsse einzelner Mauerwerkskomponenten ohne den störenden Einfluss unvermeidbarer Streuungen im Experiment qualitativ als auch – in eingeschränktem Maße – quantitativ bewertet werden. Der vorliegende Beitrag berichtet über zwei Untersuchungsreihen, in denen sich der Einfluss der Mörtelfestigkeit und der Lagerfugendicke auf die Biegezugfestigkeit und die zentrische Zugfestigkeit parallel zu den Lagerfugen offensichtlich herausstellen. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sensitivitätsanalyse und Parameteridentifikation von bestehenden Mauerwerkstrukturen
Authors: Schlegel Roger , Will Johannes
Published: December 2007

Der Beitrag stellt neue Softwareentwicklungen und Simulationsverfahren vor, mit denen es möglich ist, komplexe Simulationsmodelle hinsichtlich ihrer Prognosefähigkeit, Robustheit und Abhängigkeit von streuenden Inputparametern zu überprüfen. Am Beispiel der Untersuchung bestehender Mauerwerkstrukturen wird gezeigt, wie mit Hilfe von Sensitivitätsstudien die Einflüsse einzelner Inputparameter bzw. Inputparametergruppen auf die Ergebnisgrößen eines numerischen Simulationsmodells ermittelt werden können. Auf der Basis von Sensitivitätsanalysen können anschließend mit Hilfe von Parameteridentifikationen gezielt fehlende Werte oder Wertebereiche von Inputparametern durch den inversen Abgleich von berechneten Ergebnissen mit gemessenen Werten ermittelt werden. Damit ist es möglich, sowohl fehlende bzw. auf experimentellem Wege nicht oder nur sehr aufwendig bestimmbare Materialkenngrößen zu erhalten als auch die erforderliche Prognosefähigkeit eines Simulationsmodells sicherzustellen. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mauerwerkswände unter zyklischer Schubbeanspruchung
Authors: Butenweg Christoph , Gellert Christoph , Meskouris Konstantin
Published: December 2007

Die Tragfähigkeit von unbewehrten Mauerwerkswänden unter Erdbebenbeanspruchung wird in den Bemessungsnormen durch analytische Berechnungsformeln als Minimum der möglichen Versagensformen von Mauerwerksschubwänden abgeschätzt. Der seismische Standsicherheitsnachweis erfolgt kraftbasiert durch die Gegenüberstellung der Wandkapazität mit der nach dem Antwortspektrenverfahren ermittelten maximalen Beanspruchung. Der kraftbasierte Ansatz führt jedoch oft dazu, dass traditionelle Mauerwerksbauten schon bei moderaten Erdbebeneinwirkungen nicht mehr nachgewiesen werden können. Hier helfen verformungsbasierte Verfahren weiter, mit denen die Tragwerksreserven wesentlich besser ausgenutzt werden können. Grundlage zur Anwendung solcher Verfahren ist die Kenntnis der zyklischen Last‐Verformungskurven für die am horizontalen Lastabtrag beteiligten Schubwände. Der Verlauf der Kurven ist abhängig von der Wandgeometrie, der vertikalen Auflast, der Stein/Mörtel‐Kombination und dem Einspanngrad am Wandkopf. Aufgrund der Vielzahl möglicher Kombinationen stellen experimentelle Untersuchungen immer nur Tastuntersuchungen dar, so dass für eine parametrisierte Beschreibung der Kurven ergänzend numerische Simulationen und analytische Ansätze hinzugezogen werden müssen.

In dem Beitrag wird die Problematik der Definition von zyklischen Last‐Verformungskurven diskutiert. Zunächst werden die verschiedenen Möglichkeiten zur Approximation der zyklischen Last‐Verformungskurven vorgestellt und hinsichtlich ihrer Qualität und praktischen Anwendbarkeit bewertet. Im Anschluss wird daraus ein Konzept für die Definition der Last‐Verformungskurven abgeleitet. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Festlegung von Ertüchtigungsmaßnahmen für erdbebengefährdete Bauwerke auf der Grundlage von Kollapsanalysen
Authors: Jäger Wolfram , Bakeer Tammam
Published: December 2007

Nachdem das Erdbeben von Dezember 2003 der Zitadelle von Bam, dem größten Lehmbaukomplex der Welt, schwerste Schäden zufügte, wurden viele Maßnahmen zur Beräumung und zum Wiederaufbau der Anlage eingeleitet. Der hohe Zerstörungsgrad wirft die Frage nach der Ertüchtigung der Bauwerke beim Wiederaufbau auf. Um die Versagensursachen der Gebäude abklären zu können, wurde für zwei Räume eines Hauses eine Einsturzsimulation durchgeführt. Dabei kam die Diskrete Elementmethode (DEM) gekoppelt mit der Finiten‐Element‐Methode (FEM) zum Einsatz. Für die Erdbebenanalyse wurde die Standard‐Software LS‐DYNA angewendet. Das Mauerwerk innerhalb der Diskreten Elemente ist mittels Makromodellierung verschmiert abgebildet worden. Die Elementierung wurde mit Hilfe einer CAD‐Software erstellt, und zwar so, dass Versagensflächen Grenzflächen der Diskreten Elemente darstellen. Es wurde die Einsturzsimulation des Tragwerks zuerst im Originalzustand ohne Bewehrung durchgeführt, um die Schwachstellen und die Bruchsequenz zu ermitteln. Danach erfolgte die schrittweise Ertüchtigung durch Bewehrung aus Glasfaserstäben, die systematisch an verschiedenen Stellen angeordnet wurden, jeweils verbunden mit einer erneuten Analyse des Gesamtverhaltens. Auf diese Weise konnte die minimal notwendige Bewehrung bestimmt werden, um den Einsturz bei einem erneuten Erdbeben gleicher Art und Stärke zu verhindern. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
α‐Phenyl‐n‐tert‐butyl‐nitrone reduces lipopolysaccharide‐induced white matter injury in the neonatal rat brain
Authors: Fan Lir‐Wan , Mitchell Helen J. , Tien Lu‐Tai , Zheng Baoying , Pang Yi , Rhodes Philip G. , Cai Zhengwei
Published: December 2007

Lipopolysaccharide (LPS)‐induced white matter injury in the neonatal rat brain is at least partially associated with oxidative stress. α‐Phenyl‐n‐tert‐butyl‐nitrone (PBN) (100 mg/kg) significantly attenuated LPS (1 mg/kg)‐induced brain injury, as indicated by the reduction in bilateral ventricular enlargement, apoptotic cell death of oligodendrocytes (OLs), and the loss of OL immunoreactivity in the neonatal rat brain. Protection of PBN was linked with the attenuated oxidative stress induced by LPS, as indicated by the decreased elevation of 8‐isoprostane content and by the reduced number of 4‐hydroxynonenal or malondialdehyde positive OLs following LPS exposure. Interestingly, while LPS exposure elevated, rather than depleted, levels of the reduced glutathione (GSH) and the GSH/GSSG (oxidized form) ratio, LPS exposure significantly suppressed glutathione peroxidase activity in the rat brain. PBN attenuated LPS‐induced alterations in glutathione homeostasis in the rat brain. Additionally, the inflammatory responses were also reduced in the PBN‐treated brain, as indicated by the decreased number of activated microglia following LPS exposure and by the consequently decreased elevation of interleukin1‐β and tumor necrosis factor‐α contents in the rat brain. The overall results suggest that antioxidant PBN, more than a straightforward free radical scavenger, may also involve anti‐inflammatory and anti‐apoptotic properties in protection of the neonatal rat brain from LPS‐induced injury. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008.
Inhibition of Müller glial cell division blocks regeneration of the light‐damaged zebrafish retina
Authors: Thummel Ryan , Kassen Sean C. , Montgomery Jacob E. , Enright Jennifer M. , Hyde David R.
Published: December 2007

The adult zebrafish retina possesses a robust regenerative response. In the light‐damaged retina, Müller glial cell divisions precede regeneration of rod and cone photoreceptors. Neuronal progenitors, which arise from the Müller glia, continue to divide and use the Müller glial cell processes to migrate to the outer nuclear layer and replace the lost photoreceptors. We tested the necessity of Müller glial cell division for photoreceptor regeneration. As knockdown tools were unavailable for use in the adult zebrafish retina, we developed a method to conditionally inhibit the expression of specific proteins by in vivo electroporation of morpholinos. We determined that two separate morpholinos targeted against the proliferating cell nuclear antigen (PCNA) mRNA reduced PCNA protein levels. Furthermore, injection and in vivo electroporation of PCNA morpholinos immediately prior to starting intense light exposure inhibited both Müller glial cell proliferation and neuronal progenitor marker Pax6 expression. PCNA knockdown additionally resulted in decreased expression of glutamine synthetase in Müller glia and Müller glial cell death, while amacrine and ganglion cells were unaffected. Finally, histological and immunological methods showed that long‐term effects of PCNA knockdown resulted in decreased numbers of Müller glia and the failure to regenerate rod photoreceptors, short single cones, and long single cones. These data suggest that Müller glial cell division is necessary for proper photoreceptor regeneration in the light‐damaged zebrafish retina and are consistent with the Müller glia serving as the source of neuronal progenitor cells in regenerating teleost retinas. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008.
Behavioral and synaptic defects in C. elegans lacking the NK‐2 homeobox gene ceh‐28
Authors: Ray Paramita , Schnabel Ralf , Okkema Peter G.
Published: December 2007

C. elegans pharyngeal behavior consists of two distinct types of muscle contractions, termed pumping and peristalsis. Pumping ingests and concentrates bacteria in the anterior pharyngeal lumen, and it is occasionally followed by a transient peristaltic contraction that carries ingested bacteria through the posterior pharyngeal isthmus. These behaviors are controlled by a small pharyngeal nervous system consisting of 20 neurons that is almost completely independent of the extra‐pharyngeal nervous system. The cholinergic motor neuron M4 controls peristalsis via synapses with the posterior isthmus muscles. Here we show that the NK‐2 family homeobox gene ceh‐28 is expressed in M4, where it regulates synapse assembly and peristalsis. ceh‐28 mutants exhibit frequent and prolonged peristalses, and treatment with agonists or antagonists of muscarinic acetylcholine receptors can phenocopy or suppress ceh‐28 mutant defects, respectively. Synapses in ceh‐28 mutant M4 cells are irregularly spaced and sized, and they are abnormally located along the full length of the isthmus. We suggest that CEH‐28 inhibits synaptogenesis, and that ceh‐28 mutant behavioral defects result from excessive or ectopic stimulation of muscarinic acetylcholine receptors in the isthmus muscles. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008
NF‐kB induces lung maturation during mouse lung morphogenesis
Authors: Londhe Vedang A. , Nguyen Hanh T. , Jeng Jade‐Ming , Li Xia , Li Changgong , Tiozzo Caterina , Zhu Nianling , Minoo Parviz
Published: December 2007

Lung maturation is hallmarked by the appearance of surfactant‐producing alveoli during transition from the saccular to alveolar stage of lung development. Inflammation can disrupt this process and accelerate lung maturity following intrauterine amniotic infection (chorioamnionitis). Nuclear factor kB (NF‐kB) is a transcription factor central to multiple inflammatory and developmental pathways, including dorsal–ventral patterning in fruit flies, limb and mammary and submandibular gland development in mice, and branching morphogenesis in chick lungs. Given its shared role in inflammation and developmental signaling, we hypothesized that overexpression of NF‐kB targeted to the lung epithelium would exert maturational effects on alveolar development. We generated transgenic mice with lung‐specific overexpression of the RelA subunit of NF‐kB using a surfactant protein C promoter construct. Our results showed that RelA overexpression in the lung yields increased alveolar type I and type II cells. These findings are consistent with a model whereby NF‐kB may induce maturation of lung development through decreased apoptosis of epithelial cells. Developmental Dynamics 237:328–338, 2008. © 2007 Wiley‐Liss, Inc.
System for tamoxifen‐inducible expression of cre‐recombinase from the Foxa2 locus in mice
Authors: Park Eon Joo , Sun Xiaoxia , Nichol Peter , Saijoh Yukio , Martin James F. , Moon Anne M.
Published: December 2007

To study the roles of key transcription factor networks, growth factors, and signaling molecules in the endoderm, notochord, and floorplate, we developed an inducible Cre‐expressing system for altering gene function in this tissue. We generated an allele of Foxa2 that directs a tamoxifen‐regulated Cre in the Foxa2 expression domain (Foxa2mcm). Activity of Foxa2mcm recapitulates endogenous Foxa2 expression in endoderm, notochord, and floorplate. Efficiency of the system in a given tissue type was dose‐ and timing‐dependent. By comparing efficiency and location of Cre activity after administration of tamoxifen by oral gavage vs. intraperitoneal injection, we found that oral gavage achieves more rapid, robust recombination with less embryonic toxicity. This system will be useful for controlling the activity of floxed alleles at multiple stages of mouse embryogenesis and fetal development. Developmental Dynamics 237:447–453, 2008. © 2007 Wiley‐Liss, Inc.
Recent applications in CEC
Authors: Huo Yuli , Kok Wim Th.
Published: December 2007

In this review, research papers on CEC are summarized that have been published between May 2005 and May 2007. Application‐oriented research is discussed in which CEC is used in biochemical and pharmaceutical studies, in the analysis of food and natural products, and in industrial, environmental, and forensic analysis. Some trends and developments in separation science that may increase the applicability of the separation technique CEC are highlighted: 2‐D separation systems and the application of nano‐ and microfluidic devices in separations.
Ionic liquids and CE combination
Authors: López‐Pastor Mercedes , Simonet Bartolomé M. , Lendl Bernhard , Valcárcel Miguel
Published: December 2007

This paper reviews and discusses the analytical combination of ionic liquids (IL) with CE. On the one hand, it shows CE as a powerful technique to separate impurities from IL as well as being capable to determine physical and chemical properties of IL. On the other hand, it also shows how IL are employed in CE separations to enhance resolution, peak efficiency and peak symmetry. Specifically, IL are used as additives in CZE, NACE, and MEKC and as support coatings of the capillary wall in electrochromatography. The integrity of the IL in the electrophoretic system as well as the roles of the cations and anions of the IL in the electrophoretic separation are also discussed.
Microemulsion electrokinetic chromatography hyphenated to atmospheric pressure photoionization mass spectrometry
Authors: Schappler Julie , Guillarme Davy , Rudaz Serge , Veuthey Jean‐Luc
Published: December 2007

CZE is an appropriate technique for separating charged species, but lacks selectivity for neutral compounds. Alternative approaches such as microemulsion electrokinetic chromatography (MEEKC) have been developed to broaden its range of applications. Hyphenation of MEEKC with MS is an attractive perspective since it can enhance sensitivity and selectivity. The on‐line coupling of MEEKC with MS, however, is not straightforward due to the low compatibility of non‐volatile surfactant additives (e.g. SDS) and the commonly used API source, namely ESI. In order to hyphenate MEEKC with MS detection, the atmospheric pressure photoionization (APPI) source was investigated. Possibilities offered by the coupling of MEEKC with APPI‐MS were highlighted for the complex separation of ionized and neutral compounds in both the positive and negative modes. MEEKC‐APPI‐MS performance, in terms of selectivity, efficiency and sensitivity was compared to CZE‐ESI‐MS and MEEKC‐ESI‐MS for the screening of doping substances (β‐blockers, central stimulants, diuretics, etc). Relevant selectivity and detectability, particularly for neutral, structurally related and isobaric compounds was demonstrated with the MEEKC‐APPI‐MS approach opening new avenues for CE‐MS, in addition to the well‐established CZE‐ESI‐MS technique.
Trends in CE‐MS 2005–2006
Authors: Gaspar Andras , Englmann Matthias , Fekete Agnes , Harir Mourad , Schmitt‐Kopplin Philippe
Published: December 2007

CE‐MS has gained further attention as a multidimensional analytical approach. The number of publications dealing with this technique is still increasing on the level of application as well as method development‐oriented approaches. Additionally, 15 reviews were published the last two years focusing on CE‐MS. An overview of all papers found to have been published within 2005 and 2006 is given in tabulated form. Additionally, four promising technical trends are chosen to be presented in detail: (i) chip‐based CE‐MS, (ii) capillary coatings in CE‐MS, (iii) new trends in CEC‐MS and (iv) the application of 2‐D CE‐MS.
A note on classical damping matrices
Authors: Luco J. Enrique
Published: December 2007

An alternative damping matrix that leads to classical normal modes and that depends explicitly on a set of prescribed modal damping ratios is presented. The alternative damping matrix can be thought of as a factorized Caughey series that allows for a simple explicit solution for the coefficients of the series and thus avoids the need to solve a potentially ill‐conditioned system of algebraic equations. The relation between the proposed damping matrix and Rayleigh, Caughey and modal damping matrices is examined. Copyright © 2008 John Wiley & Sons, Ltd.
Variants of projection‐based finite element variational multiscale methods for the simulation of turbulent flows
Authors: John Volker , Kindl Adela
Published: December 2007

Some variants of a three‐scale projection‐based finite element variational multiscale (VMS) method are studied for turbulent channel flow computations at Reτ=180. Different spaces for the large scales, two eddy viscosity models and two ways of discretizing the projection terms in time are explored. The results obtained with the resolved small scales in the definition of the eddy viscosity are very sensitive to the temporal discretization of the projection terms. The computations were performed on three grids commonly used in turbulent channel flow simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Wenn Sternleichen Signale senden
Authors: Lesch Harald , Jessner Axel
Published: December 2007

Kosmische Elektrotechnik: Pulsare strahlen intensiver als jedes andere Objekt im Universum. Astrophysiker sind den rotierenden Neutronensternen auf der Spur – und finden dabei die Naturgesetze der Erde auch am Rande der Materie bestätigt
Das Geheimnis der grünen Haut
Authors: Karsten Ulf , Schumann Rhena , Gustavs Lydia , Friedl Thomas
Published: December 2007

Sie sind überall: Mikroalgen besiedeln Hausfassaden, Böden und Bäume. Selbst widrige Lebensumstände stören die Algengemeinschaften kaum. Wie sich die Biofilme schützen und immer wieder an ihre Umwelt anpassen, interessiert auch Grundlagenforscher
Unser Wort des Jahres
Authors: Kleiner Matthias
Published: December 2007

Die Exzellenzinitiative bringt nicht nur die deutsche Wissenschaft weit voran – sondern das ganze Land und seine Gesellschaft
Der Preis des Todes
Authors: Krüger Oliver
Published: December 2007

Religiöse Rituale gelten als langlebig und kaum veränderbar. Die Bestattungskultur in den Vereinigten Staaten zeigt jedoch, dass auch sie sich ständig wandeln – nicht zuletzt aus kommerziellen Gründen
Platelet count is not a predictor of the presence or development of gastroesophageal varices in cirrhosis
Authors: Qamar Amir A. , Grace Norman D. , Groszmann Roberto J. , Garcia-Tsao Guadalupe , Bosch Jaime , Burroughs Andrew K. , Maurer Rie , Planas Ramon , Escorsell Angels , Garcia-Pagan Juan Carlos , Patch David , Matloff Daniel S. , Makuch Robert
Published: December 2007

Current guidelines recommend esophagogastroduodenoscopy (EGD) in patients with cirrhosis to screen for gastroesophageal varices (GEV). Thrombocytopenia has been proposed as a noninvasive test to predict the presence of GEV. There is no agreement regarding a specific platelet count (PLT) that can reliably predict GEV. The present longitudinal study aims to (1) further investigate the relationship between varices and PLT at the time of endoscopy, (2) investigate whether changes in PLT from the baseline over time can predict the development of GEV, and (3) investigate whether changes in PLT correlate with the hepatic venous pressure gradient (HVPG). A secondary analysis was conducted for 213 subjects with compensated cirrhosis with portal hypertension but without GEV enrolled in a randomized, placebo-controlled, double-blind trial of a nonselective beta-blocker used to prevent GEV. PLTs were obtained every 3 months, and HVPG measurements and EGD were done annually. The PLTs were compared between subjects who did and did not develop GEV. In a median follow-up of 54.9 months, 84 patients developed GEV. PLT was greater than 150,000 in 15% of patients at the development of GEV. A receiver operating curve did not show any PLT with high sensitivity or specificity for the presence of GEV. Subjects with clinically insignificant portal hypertension (HVPG < 10 mm Hg) whose PLT remained greater than 100,000 had a 2-fold reduction in the occurrence of GEV (

P

= 0.0374). A significant correlation was found between HVPG and PLT at the baseline, year 1, and year 5 (

P

< 0.0001).

Conclusion:

Cross-sectional or longitudinal evaluations of PLTs are inadequate noninvasive markers for GEV. Patients with mild portal hypertension whose PLT remains greater than 100,000 have significantly less risk of GEV. Although HVPG correlates somewhat with PLT, changes in PLT cannot be used as a surrogate for HVPG changes. (Hepatology 2008;47:153–159.)
The synthesis and characterization of polymerizable and biocompatible N‐maleic acyl‐chitosan
Authors: Zhu Aiping , Pan Yingnan , Liao Tianqing , Zhao Feng , Chen Tian
Published: December 2007

Biocompatible and polymerizable natural macromolecules have been found to provide great advantages in the preparation of hydrogels, which have wide applications in the fields of tissue engineering and polymeric drug delivery systems. To develop a new biocompatible polymerizable chitosan derivative, N‐maleic acyl‐chitosan (NMCS) was synthesized in this study. This novel biomaterial was designed from the N‐acylation of chitosan with maleic anhydride introducing functional carboxyl and vinylated (CC) groups. The structure of NMCS was characterized by FTIR, 1H NMR, element analysis, and X‐ray diffraction (XRD). NMCS can be dissolved into water because of its decreased crystallinity compared with chitosan. The NMCS's multiporous and microgel morphology was revealed by transmission electron microscope (TEM). Crosslinked hydrogel films can be successfully obtain through the macromolecular polymerization of NMCS. Subsequently, 3T3 fibroblasts were cultured onto the surface of the polymerized NMCS (P‐NMCS) films to examine the capability of cell attachment and proliferation. Results from the cell culture demonstrate that P‐NMCS films provide significant improvement in cell attachment and proliferation over unmodified chitosan. The improved P‐NMCS cytocompatibility is expected to provide substantial contributions to tissue engineering in the future. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
In vitro degradation and in vivo biocompatibility of poly(lactic acid) mesh for soft tissue reinforcement in vaginal surgery
Authors: de Tayrac Renaud , Chentouf Samir , Garreau Henri , Braud Christian , Guiraud Isabelle , Boudeville Philippe , Vert Michel
Published: December 2007

This study was aimed at evaluating the in vitro degradation, the in vivo biocompatibility and at comparing the effects of two methods of sterilization on poly(L‐lactic acid) (PLA94) resorbable mesh. The mesh was manufactured to be used as surgical soft tissue reinforcement in the vaginal area. Samples of 100 mg of PLA94 mesh (10 × 10 mm2) were immersed in isoosmolar 0.13M, pH 7.4 phosphate buffer solution at 37°C, during 12 months. The hydrolytic degradation up to 12 months after immersion was monitored by measuring weight loss, mesh area changes, and by various analytical techniques namely Differential scanning calorimetry (DSC), capillary zone electrophoresis (CZE), size exclusion chromatography (SEC), and environmental scanning electron microscopy (ESEM). Specimens of nonsterilized, ethylene‐oxide (ETO) sterilized, and γ‐ray sterilized PLA94 mesh were compared. Fifteen samples were implanted in an incisional hernia Wistar rat model. Histopathology was performed up to 90 days after implantation to evaluate the inflammatory response and the collagen deposition. Although the decrease of molecular weight due to polymer chain scissions started 6 weeks after in vitro immersion, water‐soluble degradation products and decrease of tensile strength appeared after 8 months only. Analyses showed also that ETO sterilization did not affect the degradation of the PLA94 mesh. In contrast, γ‐ray sterilization increased very much the sensitivity of the mesh to the hydrolytic degradation. In vivo, the PLA94 mesh exhibited good biocompatibility over the investigated time period. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Bone regeneration by using scaffold based on mineralized recombinant collagen
Authors: Wang Y. , Cui F. Z. , Hu K. , Zhu X. D. , Fan D. D.
Published: December 2007

Bone regeneration was achieved in the 15‐mm segmental defect model in the radius of rabbit by using the scaffold based on mineralized recombinant collagen for the first time. The recombinant collagen was recombinant human‐like type I collagen, which was produced by cloning a partial cDNA that was reversed by mRNA from human collagen α1(I) and transferred to E. coli. The scaffold material nano‐hydroxyapatite/recombinant human‐like collagen/poly(lactic acid) (nHA/RHLC/PLA) was developed by biomimetic synthesis. Thermo gravimetric analysis, X‐ray diffraction and scanning electron microscopy were applied to exhibit that the scaffold showed some features of natural bone both in main component and hierarchical microstructure. The percentages of organic phase and inorganic phase of nHA/RHLC were similar to that of natural bone. The three‐dimensional porous scaffold materials mimic the microstructure of cancellous bone. In the implantation experiment, the segmental defect was healed 24 weeks after surgery, and the implanted composite was completely substituted by new bone tissue. The results of the implantation experiment were very comparable with that of the scaffold based on mineralized animal‐sourced collagen. It is concluded that the scaffold based on mineralized recombinant collagen maintains the advantages of mineralized animal‐sourced collagen, while avoids potential virus‐dangers. The scaffold is a promising material for bone tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Neural tissue engineering of the CNS using hydrogels
Authors: Nisbet David R. , Crompton Kylie E. , Horne Malcolm K. , Finkelstein David I. , Forsythe John S.
Published: December 2007

Current therapies have limited capacity to curtail disease progression or damage of the central nervous system (CNS) of adult mammals and successful regeneration following injury or disease does not occur. Regeneration of the CNS is limited by physical and chemical inhibitory barriers within the injured environment and the absence of positive cues that elicit and guide repair. Neural tissue engineering strategies focus on developing scaffolds that artificially generate favourable cellular microenvironments that attempt to tip the balance in favour of regeneration. Some recent advances using scaffolds to promote regeneration within the CNS, particularly in conjunction with stem cells, has generated promising results. This review focuses on hydrogel scaffolds which have been used extensively in neural tissue engineering applications and addresses the physical and chemical modifications of these materials to promote nerve regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Study of the micro‐structural properties of RISUG®—A newly developed male contraceptive
Authors: Kumar Sunil , Roy Sohini , Chaudhury Koel , Sen Prasenjit , Guha Sujoy K.
Published: December 2007

A new male contraceptive given the name RISUG® (an acronym for reversible inhibition of sperm under guidance) and presently undergoing advanced clinical trials has been developed. When injected into the lumen of the vas deferens, its polyelectrolytic nature induces a surface charge imbalance on sperm membrane system leading to the leakage of enzymes essential for fertilization. Contact mode atomic force microscopy (AFM) has been used to analyze quantitatively the micro‐structural properties of RISUG® and its precipitate in various systems. Hydrolysis of the contraceptive gel resulted in the formation of pores of varying dimensions. RISUG® being a highly charged molecule, as evident from zeta potential measurements, has a tendency to form a complex with ionic biomolecules present in the seminal plasma. This is supported by the experimental observations using AFM. This RISUG®‐biomolecule complex possibly acts as an ionic trap for spermatozoa passing through the vas deferens. Micro‐structural properties of RISUG® including amplitude (root mean square, peak‐to‐valley distance, skewness and kurtosis) and spatial roughness have been studied to understand its response to various physiological conditions. Significant alterations in the surface charge distribution of the sperm cell is observed on exposure to RISUG®. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Effect of In vitro degradation of poly(D,L‐lactide)/β‐tricalcium composite on its shape‐memory properties
Authors: Zheng Xiaotong , Zhou Shaobing , Yu Xiongjun , Li Xiaohong , Feng Bo , Qu Shuxin , Weng Jie
Published: December 2007

The in vitro degradation characteristic and shape‐memory properties of poly(D,L‐lactide) (PDLLA)/β‐tricalcium phosphate (β‐TCP) composites were investigated because of their wide application in biomedical fields. In this article, PDLLA and crystalline β‐TCP were compounded and interesting shape‐memory behaviors of the composite were first investigated. Then, in vitro degradation of the PDLLA/β‐TCP composites with weight ratios of 1:1, 2:1, and 3:1 was performed in phosphate buffer saline solution (PBS) (154 mM, pH 7.4) at 37°C. The effect of in vitro degradation time for PDLLA/β‐TCP composites on shape‐memory properties was studied by scanning electron microscopy, differential scanning calorimetry, gel permeation chromatography, X‐ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The changes of structural morphology, glass transition temperature (Tg), molecular weight, and weight loss of composites matrix and pH change of degradation medium indicated that shape‐memory effects at different degradation time were nonlinearly influenced because of the breaking down of polymer chain and the formation of degradation products. Furthermore, the results from XRD and FTIR implied that the degradation products, for example, hydroxyapatite (HA), calcium hydrogen phosphate (CaHPO4), and calcium pyrophosphate (Ca2P2O7) phases also had some effects on shape‐memory properties during the degradation. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Comparative histomorphometric and tomographic analysis of maxillary sinus floor augmentation in rabbits using autografts and xenografts
Authors: Sicca Cristina Miguel , Corotti Mauro Vinícius , Sgarbosa Sílvia Helena Pereira Vergili , Cestari Tania Mary , Cavalcanti Marcelo Gusmão Paraíso , Ferreira Paulo Martins , Taga Rumio , Granjeiro José Mauro
Published: December 2007

Our goal was to evaluate bone neoformation promoted by a bovine xenograft composite (XC) compared with autogenous graft for maxillary sinus augmentation in a rabbit model. The left maxillary sinus of 18 male rabbits was filled with 200 mg of cortical and cancellous autogenous bone and the right sinus was filled with 200 mg of a composite comprised organic and inorganic bovine matrices, pool of bBMPs and collagen. Postoperative implant intervals of 2, 4, and 8 weeks were analyzed. Differences in the bone optical density among the groups and experimental periods were evaluated by computed tomography analysis. The tissue response was evaluated by histomorphometric analysis of the newly formed bone, connective tissue and/or granulation tissue, residual material, and bone marrow. The tomographic analyses showed a maximum optical density in the 4‐week period for both groups. Histologically, an inflammatory infiltrate was observed at 2 weeks in the XC group but exclusively around the organic particles of the biomaterial. Regarding to the amount of newly formed bone, no statistical differences (p > 0.05) were observed among the two treatments throughout the implant intervals. However, by the end of the 8 weeks, the quantity of bone marrow was two times greater (p < 0.05) in the control group than in the XC group. In conclusion, the xenograft composite promotes formation of new bone in a similar fashion to autogenous bone and could therefore be considered a biomaterial with potential applications as a bone substitute in maxillary sinus floor augmentation. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008