bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of Isoprostanes as Markers of Oxidative Stress in Neuronal Tissue
Authors: Milatovic Dejan , Aschner Michael
Published: February 2009

Oxidative stress is implicated in the pathogenesis of a variety of human diseases, including neurodegenerative disease, atherosclerosis, and cancer, as well as progressive and even normal aging processes. Increased generation of free radicals derived primarily from molecular oxygen has also been associated with neuronal damage induced by a variety of environmental agents. However, measuring oxidative stress in biological systems is complex and requires accurate quantification of either free radicals or damaged biomolecules. One method for quantifying oxidative injury is to measure lipid peroxidation caused by free radicals. One group of these peroxidation products, F2‐isoprostanes (F2‐IsoPs), is derived by free‐radical peroxidation of arachidonic acid (AA). These prostaglandin F2‐like compounds are currently the most accurate measure of oxidative damage in vivo. This unit summarizes current methodology for quantifying F2‐IsoPs and discusses the utility of these and other prostaglandin (PG)‐like compounds as in vivo biomarkers for oxidative stress in neuronal tissues.Curr. Protoc. Toxicol. 39:12.14.1‐12.14.12. © 2009 by John Wiley & Sons, Inc.
Analysis of Oxidative Modification of Proteins
Authors: Yan Liang‐Jun
Published: February 2009

Proteins are targets of oxidative modification. This unit describes detailed procedures for the analysis of popular indices of protein oxidation including protein carbonyl formation, loss of protein thiols, and nitrotyrosine and dityrosine formation, as well as isoaspartate formation. Procedures are detailed for the analysis of protein carbonyls labeled with 2,4‐dinitrophenylhydrazine, tritiated sodium borohydride, and biotin‐hydrazide, followed by detection measurements that are based on the distinguishing feature of each labeling chemical. Methods are outlined for the determination of protein cysteine oxidation by quantifying the loss of free protein thiols using radiolabeled [14C]‐iodoacetamide. Protocols are described for the measurement of protein dityrosine by gas chromatography/mass spectrometry, as are the details for the detection of protein nitrotyrosine by a competitive ELISA approach. Finally, methods are described for the quantification of protein‐bound isoaspartate using protein‐L‐isoaspartyl methyltransferase that converts aberrant L‐isoaspartyl residues in peptides and proteins to normal aspartyl residues. Curr. Protoc. Protein Sci. 55:14.4.1‐14.4.27. © 2009 by John Wiley & Sons, Inc.
Tandem Affinity Purification of Proteins
Authors: Günzl Arthur , Schimanski Bernd
Published: February 2009

Tandem affinity purification (TAP) is a very efficient method to isolate proteins, protein complexes, or ribonucleoprotein particles from crude extracts. The method depends on the expression of one protein component fused N‐ or C‐terminally to a TAP tag in the organism of interest. The TAP tag is a composite tag consisting of two different epitope domains and a protease cleavage site, and it facilitates the purification of the tagged protein in two consecutive, high‐affinity chromatography steps. Combined, the two steps are typically so efficient that a protein complex can be purified virtually to homogeneity without the need for protein overexpression. If the tag does not interfere with protein function, TAP is likely to yield an intact protein complex because all steps of the procedure are carried out under nondenaturing conditions. In this unit, a TAP procedure is detailed which employs a novel epitope combination termed PTP. Curr. Protoc. Protein Sci. 55:19.19.1‐19.19.16. © 2009 by John Wiley & Sons, Inc.
Skin Allograft Rejection
Authors: McFarland Hugh I. , Rosenberg Amy S.
Published: February 2009

Skin allograft rejection is a test of the competence of T lymphocytes to mediate in vivo tissue destruction, which in turn reflects their role in critical functions such as anti‐viral and tumor immunity. The tail‐skin graft procedure described in this unit is useful predominantly because of the ease of preparation and resistance to ischemic (nonspecific) necrosis. Additionally, it is not necessary to sacrifice the donor mouse. However, rejection of tail‐skin grafts should not be used to test for genetic homogeneity in breeding experiments or to detect minor histocompatibility (minor‐H) antigens because tail skin is less sensitive than trunk skin in detecting such differences. Curr. Protoc. Immunol. 84:4.4.1‐4.4.13. © 2009 by John Wiley & Sons, Inc.
Human Natural Killer Receptors, Co‐Receptors, and Their Ligands
Authors: Biassoni Roberto
Published: February 2009

In the last 20 years, the study of human natural killer (NK) cells has moved from the first molecular characterizations of very few receptor molecules to the identification of a plethora of receptors displaying surprisingly divergent functions. Our laboratory has contributed to the description of inhibitory receptors and their signaling pathways, important in fine regulation in many cell types, but unknown until their discovery in the NK cells. Inhibitory function is central to regulating NK‐mediated cytolysis, with different molecular structures evolving during speciation to assure its persistence. Only in the last ten years has it become possible to characterize the NK triggering receptors mediating natural cytotoxicity, leading to an appreciation of the existence of a cellular interaction network between effectors of both natural and adaptive immunity. This report reviews the contemporary history of molecular studies of receptors and ligands involved in NK cell function, characterizing the ligands of the triggering receptor and the mechanisms for finely regulating their expression in pathogen‐infected or tumor cells. Curr. Protoc. Immunol. 84:14.10.1‐14.10.40. © 2009 by John Wiley & Sons, Inc.
Molecular Cloning and Characterization of MHC Class I– and II–Restricted Tumor Antigens Recognized by T Cells
Authors: Wang Rong‐Fu
Published: February 2009

T cells play a central role in cancer immunosurveillance, autoimmune, and infectious diseases. Identification of MHC class I– and II–restricted T cell peptides is a critical step for the development of effective vaccines against cancer and infectious diseases. This unit describes a cDNA expression system and a genetic targeting expression system for the cloning of genes encoding for MHC class I– and II–restricted antigens recognized by antigen‐specific CD8+ and CD4+ T cells. Curr. Protoc. Immunol. 84:20.10.1‐20.10.29. © 2009 by John Wiley & Sons, Inc.
Derivation of Epicardium‐Derived Progenitor Cells (EPDCs) from Adult Epicardium
Authors: Smart Nicola , Riley Paul R.
Published: February 2009

The epicardium has, like the other cell lineages of the terminally differentiated adult heart, long been regarded as quiescent, incapable of migration or differentiation. In contrast, the embryonic epicardium possesses an innate ability to proliferate, migrate, and differentiate into a number of mature cardiovascular cell types, including vascular smooth muscle cells, fibroblasts, cardiomyocytes, and, arguably, some endothelial cells. In recapitulating its essential developmental role, we recognized the ability of the actin‐binding peptide thymosin β4 (Tβ4) to induce epicardium‐derived progenitor cell (EPDC) migration from adult heart and noted the derivation of cell types originating from embryonic epicardium. This protocol provides a means of enabling adult EPDC outgrowth and culture. We establish a model system in which to study the ability of factors to influence the migration of vascular precursors and their differentiation and to move towards screening of small molecules ex vivo prior to clinical trials of therapeutic cardiac repair. Curr. Protoc. Stem Cell Biol. 8:2C.2.1‐2C.2.9. © 2009 by John Wiley & Sons, Inc.
Fungal Transmission of Plant Viruses
Authors: Rochon D'Ann
Published: February 2009

Fungal zoospores of Olpidium species transmit several viruses in the family Tombusviridae as well as in the Ophio‐ and Varicosavirus genera. This unit describes procedures for virus transmission by Olpidium sp. The method is useful for assessing fungal transmissibility of a given virus as well as for further studies on molecular and biological aspects of virus/vector interaction. Curr. Protoc. Microbiol. 12:16B.4.1‐16B.4.17. © 2009 by John Wiley & Sons, Inc.
Structure‐Based Approaches to Antibiotic Drug Discovery
Authors: Nicola George , Abagyan Ruben
Published: February 2009

The development of antimicrobials has advanced tremendously over the past century. However, as our production capacity increases, the threat of resistance is ever‐present. To combat this resistance, two main avenues of drug discovery are being pursued: identifying new microbial proteins for which to direct drug discovery efforts, and designing innovative drugs that target existing proteins. The advent of structural genomics research has advanced to the point of rapidly discovering novel microbial protein targets. In addition, modern tools of computational biology greatly enhance the speed and reliability of antimicrobial discovery. The various steps of this process are outlined and discussed, including virtual ligand screening, pocket identification, and compound optimization. Curr. Protoc. Microbiol. 12:17.2.1‐17.2.10. © 2009 by John Wiley & Sons, Inc.
Anaerobic Cell Culture
Authors: Speers Allison M. , Cologgi Dena L. , Reguera Gemma
Published: February 2009

Although the ability of some microorganisms to grow without O2 has long been recognized, the application of new methodologies has greatly expanded the known diversity and potential of anaerobic microorganisms and processes. In particular, anaerobic techniques that permit the successful cultivation of microorganisms on solid media have opened new avenues for the study of the physiology and metabolic potential of many new microorganisms using molecular, genomic, and proteomic tools. One technique above all has proven instrumental for anaerobic studies over the years: the use of the anaerobic chamber. This unit gives a brief description of the methods used for the cultivation of anaerobic microorganisms, and describes in detail the principles and applications of anaerobic chambers, with special emphasis on vinyl glove boxes. The methodologies described in this unit should provide the interested but inexperienced investigator with the basic tools to successfully cultivate anaerobic microorganisms and study anaerobic processes. Curr. Protoc. Microbiol. 12:A.4F.1‐A.4F.16. © 2009 by John Wiley & Sons, Inc.
Fabrication and Optical Characteristics of Position‐Controlled ZnO Nanotubes and ZnO/Zn0.8Mg0.2O Coaxial Nanotube Quantum Structure Arrays
Authors: Yoo Jinkyoung , Hong Young Joon , Jung Hye Seong , Kim Yong‐Jin , Lee Chul‐Ho , Cho Jeonghui , Doh Yong‐Joo , Dang Le Si , Park Kyung Ho , Yi Gyu‐Chul
Published: February 2009

The position‐controlled growth and structural and optical characteristics of ZnO nanotubes and their coaxial heterostructures are reported. To control both the shape and position of ZnO nanotubes, hole‐patterned SiO2 growth‐mask layers on Si(111) substrates with GaN/AlN intermediate layers using conventional lithography are prepared. ZnO nanotubes are grown only on the hole patterns at 600 °C by catalyst‐free metal–organic vapor‐phase epitaxy. Furthermore, the position‐controlled nanotube growth method allows the fabrication of artificial arrays of ZnO‐based coaxial nanotube single‐quantum‐well structures (SQWs) on Si substrates. In situ heteroepitaxial growth of ZnO and Zn0.8Mg0.2O layers along the circumference of the ZnO nanotube enable an artificial formation of quantum‐well arrays in a designed fashion. The structural and optical characteristics of the ZnO nanotubes and SQW arrays are also investigated using synchrotron radiation X‐ray diffractometry and photoluminescence and cathodoluminescence spectroscopy.
Multifunctional Composites of Ceramics and Single‐Walled Carbon Nanotubes
Authors: Padture Nitin P.
Published: February 2009

Polycrystalline ceramic/single‐walled carbon nanotube (SWNT) composites possess unique grain boundaries, containing 1D tortuous SWNTs bundles that form 2D tangled embedded nets. This unprecedented grain‐boundary structure allows tailoring of multifunctional ceramic/SWNTs composites with unique combinations of desirable mechanical (toughness, strength, creep) and transport (electrical, thermal) properties. A brief discussion and analysis of recent developments in these composites are presented.
Characteristics of occupational burns in Oregon, 2001–2006
Authors: Walters Jaime K.
Published: February 2009

Background

Occupational burns are known to be a serious public health concern. This article describes work‐related burns in Oregon between 2001 and 2006.

Methods

Oregon Workers' Compensation (WC) burn claims were analyzed; data from a commercial insurance carrier (CIC) was used to characterize non‐disabling burn claims. To ensure that our primary data source (WC) captures as many burn cases as possible, we compared hospitalized cases to a regional burn center (RBC) and Oregon hospital discharge index (HDI) data.

Results

The WC burn injury rate ranged from a high of 1.8 per 10,000 workers in 2001 to a low of 1.4 per 10,000 in 2004. We identified 2,165 accepted burn claims in CIC data, of which 85% were non‐disabling. We matched data from a regional burn center to a subset of hospitalized claims from WC data and found an additional 44 cases of occupational hospitalized burns representing a 3% increase in total cases captured.

Conclusions

Occupational burns continue to be a problem for working Oregonians, and the use of additional data sources outside of WC augments our surveillance system. Am. J. Ind. Med. 52:380–390, 2009. © 2009 Wiley‐Liss, Inc.
The effects of infant births on male–female relationships in Cebus capucinus
Authors: Sheller Claire R. , King Zdanna , Jack Katharine
Published: February 2009

Most primates are characterized by cohesive male–female bonds that are maintained year round. While recent studies have addressed the selective pressures influencing the evolution of male–female relationships in primates, we know relatively little about the proximate mechanisms affecting them. It has been demonstrated that newborn white‐faced capuchins (Cebus capucinus) attract the attention of other group members and this may be an important mechanism influencing male–female relationships. We studied two groups of C. capucinus in the Area de Conservación Guanacaste, Costa Rica, between February and July 2007. A total of 348 hr of focal data were collected on all adult males (n=6) residing in each of the study groups. During our study, 13 of the 14 group females were either pregnant or lactating, and 9 infants were born. We calculated an average daily affiliation rate between all group males combined and each adult female four weeks before and four weeks after the birth of her infant. Repeated measures ANOVAs revealed no significant changes in affiliation following infant births (F=2.262, df=1, P<0.176). Results remained nonsignificant for rank (F=1.550, df=1, P<0.260) and group membership (F=0.729, df=1, P<0.429). Infant sex was the only variable with a significant effect on affiliation rates between males and females (F=10.020, df=1, P<0.019). Adult males increased their affiliation with all adult females that gave birth to male infants (n=4), while their rates decreased with all but one of the adult females with female infants (n=4). While preliminary, these results indicate that the adult males may cultivate relationships with other males at a young age. Am. J. Primatol. 71:380–383, 2009. © 2009 Wiley‐Liss, Inc.
Seasonality of LH, testosterone and sperm parameters in spider monkey males (Ateles geoffroyi)
Authors: Cerda‐Molina Ana Lilia , Hernández‐López Leonor , Chavira‐Ramírez Roberto , Cárdenas Mario , Mondragón‐Ceballos Ricardo
Published: February 2009

There are no reported data on hormonal fluctuations in black‐handed spider monkey males. On previous research about the reproductive physiology of this monkey we have found that during the dry season females show ovulatory estrogen peaks and males present the best quality semen. As part of an ongoing research, in this study we assessed seasonal variations in the concentration of serum luteinizing hormone (LH) and testosterone (T) in three adult spider monkey males to corroborate the seasonal reproductive synchrony. At the same time sperm count and motility were evaluated to search for any correlation between those sperm parameters and hormonal concentrations. We took blood and semen samples (by electroejaculation) of anesthetized males throughout the rainy (June–September) and dry (October–May) months. Our results revealed that T and LH were higher throughout the dry season and there was a significant correlation between T concentration and sperm count. Although higher during the dry season, sperm motility tended to correlate with testosterone and LH levels. These results demonstrated that black‐handed spider monkeys have a tendency to show a seasonal pattern of reproduction being the dry season the most likely time to achieve fertilization. Am. J. Primatol. 71:427–431, 2009. © 2009 Wiley‐Liss, Inc.
Estimating chimpanzee population size with nest counts: validating methods in Taï National Park
Authors: Kouakou Célestin Yao , Boesch Christophe , Kuehl Hjalmar
Published: February 2009

Successful conservation and management of wild animals require reliable estimates of their population size. Ape surveys almost always rely on counts of sleeping nests, as the animals occur at low densities and visibility is low in tropical forests. The reliability of standing‐crop nest counts and marked‐nest counts, the most widely used methods, has not been tested on populations of known size. Therefore, the answer to the question of which method is more appropriate for surveying chimpanzee population remains problematic and comparisons among sites are difficult.

This study aimed to test the validity of these two methods by comparing their estimates to the known population size of three habituated chimpanzee communities in Taï National Park [Boesch et al., Am J Phys Anthropol 130:103–115, 2006; Boesch et al., Am J Primatol 70:519–532, 2008]. In addition to transect surveys, we made observations on nest production rate and nest lifetime. Taï chimpanzees built 1.143 nests per day. The mean nest lifetime of 141 fresh nests was 91.22 days. Estimate precision for the two methods did not differ considerably (difference of coefficient of variation <5%). The estimate of mean nest decay time was more precise (CV=6.46%) when we used covariates (tree species, rainfall, nest height and age) to model nest decay rate, than when we took a simple mean of nest decay times (CV=9.17%). The two survey methods produced point estimates of chimpanzee abundance that were similar and reliable: i.e. for both methods the true chimpanzee abundance was included within the 95% estimate confidence interval. We recommend further research on covariate modeling of nest decay times as one way to improve the precision and to reduce the costs of conducting nest surveys. Am. J. Primatol. 71:447–457, 2009. © 2009 Wiley‐Liss, Inc.
Coalescent simulations of Yakut mtDNA variation suggest small founding population
Authors: Zlojutro Mark , Tarskaia Larissa A. , Sorensen Mark , Snodgrass J. Josh , Leonard William R. , Crawford Michael H.
Published: February 2009

The Yakuts are a Turkic‐speaking population from northeastern Siberia who are believed to have originated from ancient Turkic populations in South Siberia, based on archaeological and ethnohistorical evidence. In order to better understand Yakut origins, we modeled 25 demographic scenarios and tested by coalescent simulation whether any are consistent with the patterns of mtDNA diversity observed in present‐day Yakuts. The models consist of either two simulated demes that represent Yakuts and a South Siberian ancestral population, or three demes that also include a regional Northeast Siberian population that served as a source of local gene flow into the Yakut deme. The model that produced the best fit to the observed data defined a founder group with an effective female population size of only 150 individuals that migrated northwards approximately 1,000 years BP and who experienced significant admixture with neighboring populations in Northeastern Siberia. These simulation results indicate a pronounced founder effect that was primarily kin‐structured and reconcile reported discrepancies between Yakut mtDNA and Y chromosome diversity levels. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.
Socioecological correlates of facial mobility in nonhuman anthropoids
Authors: Dobson Seth D.
Published: February 2009

Facial mobility, or the variety of facial movements a species can produce, is likely influenced by selection for facial expression in diurnal anthropoids. The purpose of this study is to examine socioecological correlates of facial mobility independent of body size, focusing on social group size and arboreality as possible evolutionary agents. Group size was chosen because facial expressions are important for group cohesion, while arboreality may limit the utility of facial expressions. Data for 12 nonhuman anthropoid species were taken from previous studies and analyzed using a phylogenetic generalized least‐squares approach. Regression results indicate that group size is a good predictor of facial mobility independent of body size. No statistical support was found for the hypothesis that arboreality constrains the evolution of facial mobility. The correlation between facial mobility and group size may be a consequence of selection for more effective facial expression to help manage conflicts and facilitate bonding in larger groups. These findings support the hypothesis that the ultimate function of facial expression is related to group cohesion. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.
Dietary and physiological controls on the hydrogen and oxygen isotope ratios of hair from mid‐20th century indigenous populations
Authors: Bowen Gabriel J. , Ehleringer James R. , Chesson Lesley A. , Thompson Alexandra H. , Podlesak David W. , Cerling Thure E.
Published: February 2009

A semimechanistic model has recently been proposed to explain observed correlations between the H and O isotopic composition of hair from modern residents of the USA and the isotopic composition of drinking water, but the applicability of this model to hair from non‐USA and preglobalization populations is unknown. Here we test the model against data from hair samples collected during the 1930s–1950s from populations of five continents. Although C and N isotopes confirm that the samples represent a much larger range of dietary “space” than the modern USA residents, the model is able to reproduce the observed δ2H and δ18O values given reasonable adjustments to 2 model parameters: the fraction of dietary intake derived from locally produced foods and the fraction of keratin H fixed during the in vivo synthesis of amino acids. The model is most sensitive to the local dietary intake, which appears to constitute between 60% and 80% of diet among the groups sampled. The isotopic data are consistent with a trophic‐level effect on protein H isotopes, which we suggest primarily reflects mixing of 2H‐enriched water and 2H‐depleted food H in the body rather than fractionation during biosynthesis. Samples from Inuit groups suggest that humans with marine‐dominated diets can be identified on the basis of coupled δ2H and δ18O values of hair. These results indicate a dual role for H and O isotopic measurements of keratin, including both biological (diet, physiology) and environmental (geographic movement, paleoclimate) reconstruction. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.
Enantioselektive Katalyse mit kationischen Oxazaborolidinen
Authors: Corey E. J.
Published: February 2009

Chirale Oxazaborolidine können mit starken Protonensäuren oder durch Koordination von AlBr3 am Stickstoffatom aktiviert werden und bilden dabei sehr starke chirale Lewis‐Säuren. Die entstehenden chiralen Bor‐Elektrophile (siehe Struktur) sind leistungsfähige chirale Katalysatoren, die [4+2]‐, [3+2]‐ und [2+2]‐Cycloadditionen mit hoher Enantioselektivität vermitteln.

magnified image

In den letzten Jahrzehnten hat in der Chemie eine Revolution stattgefunden, die außerhalb unserer Disziplin – und selbst in anderen Wissenschaften – praktisch unbemerkt geblieben ist. Grundlegend gewandelt hat sich: 1) unser Verständnis davon, wie chemische Reaktionen ablaufen, 2) unsere Fähigkeit, neue Reaktionen zu entwickeln, 3) unsere Fähigkeit, Reaktionen nutzbar zu machen, die zur Synthese einer riesigen Vielfalt an nützlichen oder komplexen Molekülen geführt haben, und 4) unsere Fähigkeit, chemische Prinzipien und chemisches Wissen zum Verständnis biologischer und medizinischer Fragestellungen anzuwenden. Im Bereich der Synthesechemie ist eine ganz neue Art von Wissenschaft herangewachsen, die eine nahezu perfekte Kontrolle der absoluten und relativen Stereochemie ermöglicht und mit der gezielten Entwicklung von Katalysatoren einhergeht, deren Funktionsweisen vor Jahren noch unvorstellbar schienen. Dieser Aufsatz befasst sich mit einem speziellen Aspekt dieser Chemie, der erst in den letzten Jahren aufgetaucht ist: der Erzeugung und Anwendung der supersauren chiralen Oxazaborolidiniumionen in der enantioselektiven Katalyse. Die Fortschritte in diesem Bereich sind vielschichtiger Natur und betreffen 1) die Bildung der Katalysatoren, 2) die Aufklärung der detaillierten Mechanismen, über die sich Reaktionen steuern und beschleunigen lassen, 3) Erkenntnisse über die katalysierten Reaktionen und 4) die Entwicklung und Optimierung von Syntheseverfahren.
A Quantitative Universal Detection System for Organic Compounds in Gas Chromatography with Isotopically Enriched 13CO2
Authors: Cueto Díaz Sergio , Ruiz Encinar Jorge , Sanz‐Medel Alfredo , García Alonso J. Ignacio
Published: February 2009

Gut und günstig: Die Verdünnung von Kohlenstoffisotopen mit 13CO2 nach dem Säulvorgang zusammen mit gekoppelter Gaschromatographie, Verbrennung und EI‐MS (Ventil in Position B; siehe Bild) ist eine allgemein anwendbare Methode zur Quantifizierung organischer Verbindungen ohne Einsatz spezifischer Standards. Ein GC/MS‐Apparat lässt sich kostengünstig aufrüsten, ohne dass dabei massenspektrometrische Strukturinformationen verloren gehen.

magnified image
Total Synthesis and Absolute Configuration of the Bisanthraquinone Antibiotic BE‐43472B
Authors: Nicolaou K. C. , Lim Yee Hwee , Becker Jochen
Published: February 2009

Einladung zum T: Erstmals wurde der T‐förmige Bisanthrachinon‐Naturstoff BE‐43472B durch Totalsynthese hergestellt und seine Absolutkonfiguration aufgeklärt. Wesentliche Schritte der zentralen Kaskadensequenz sind eine Diels‐Alder‐Reaktion, die Bildung eines Halbketals und eine nucleophile aromatische ipso‐Substitution. TBS=tert‐Butyldimethylsilyl.

magnified image
Innentitelbild: Cognitive‐Performance Recovery of Alzheimer's Disease Model Mice by Modulation of Early Soluble Amyloidal Assemblies (Angew. Chem. 11/2009)
Authors: Frydman‐Marom Anat , Rechter Meirav , Shefler Irit , Bram Yaron , Shalev Deborah E. , Gazit Ehud
Published: February 2009

Die Akkumulation von β‐Amyloid (Aβ) in Form von Amyloidfibrillenablagerungen spielt eine wesentliche Rolle in der Pathogenese der Alzheimer‐Demenz, einer der häufigsten Erkrankungen des 21. Jahrhunderts. E. Gazit et al. beschreiben in ihrer Zuschrift auf S. 2015 ff. einen neuartigen Inhibitor der Aβ‐Fibrillierung, dessen Wirkmechanismus auf dem Angriff auf aromatische Erkennungsmodule und einer einzigartigen Strategie aus Cα‐Methylierung und β‐Spaltung beruht. Graphik: Tal Mazor.

magnified image
Detection and Analysis of Low‐Abundance Cell‐Surface Biomarkers Using Enzymatic Amplification in Microfluidic Droplets
Authors: Joensson Haakan N. , Samuels Michael L. , Brouzes Eric R. , Medkova Martina , Uhlén Mathias , Link Darren R. , Andersson‐Svahn Helene
Published: February 2009

Finding the few: Cell‐surface proteins are useful disease biomarkers, but current high‐throughput methods are limited to detecting cells expressing more than several hundred proteins. Enzymatic amplification in microfluidic droplets (see picture) is a high‐throughput method for detection and analysis of cell‐surface biomarkers expressed at very low levels on individual human cells. Droplet optical labels allow concurrent analysis of several samples.

magnified image
A Quantitative Universal Detection System for Organic Compounds in Gas Chromatography with Isotopically Enriched 13CO2
Authors: Cueto Díaz Sergio , Ruiz Encinar Jorge , Sanz‐Medel Alfredo , García Alonso J. Ignacio
Published: February 2009

Cheap and cheerful: Postcolumn carbon‐isotope dilution with 13CO2 in combination with the coupling of gas chromatography, combustion, and EIMS (valve in position B in the picture) provides a generic quantitative approach for every organic compound without the need for specific standards. A GC–MS instrument can be upgraded by a simple low‐cost modification without any loss of the structural information provided by electron ionization sources.

magnified image
Total Synthesis of Cribrostatin 6
Authors: Knueppel Daniel , Martin Stephen F.
Published: February 2009

Fast and furious: Cribrostatin 6, an antimicrobial and antineoplastic agent, was the target of a total synthesis where the longest linear sequence was only four steps. The key step involves a tandem 4π electrocyclic ring opening, radical cyclization, and homolytic aromatic substitution sequence to afford the tricyclic core of the natural product.

magnified image
Cover Picture: SERS Labels for Red Laser Excitation: Silica‐Encapsulated SAMs on Tunable Gold/Silver Nanoshells (Angew. Chem. Int. Ed. 11/2009)
Authors: Küstner Bernd , Gellner Magdalena , Schütz Max , Schöppler Friedrich , Marx Alexander , Ströbel Philipp , Adam Patrick , Schmuck Carsten , Schlücker Sebastian
Published: February 2009

Silica‐encapsulated SAMs …︁ (self‐assembled monolayers) on tunable Au/Ag nanoshells are described by S. Schlücker et al. in their Communication on page 1950 ff. These systems show great potential as labels for surface‐enhanced Raman scattering (SERS) in bioanalytical and biomedical applications with red laser excitation, for example, in assays and microscopy. This method combines the spectroscopic advantages of SAMs with the stability of glass shells.

magnified image
Inside Cover: Cognitive‐Performance Recovery of Alzheimer's Disease Model Mice by Modulation of Early Soluble Amyloidal Assemblies (Angew. Chem. Int. Ed. 11/2009)
Authors: Frydman‐Marom Anat , Rechter Meirav , Shefler Irit , Bram Yaron , Shalev Deborah E. , Gazit Ehud
Published: February 2009

The accumulation of amyloid‐β (Aβ) as amyloid fibril deposits may play a central role in the pathogenesis of Alzheimer's disease, which is among the most common diseases of the 21st century. E. Gazit and co‐workers describe in their Communication on page 1981 ff. a novel Aβ fibrilization inhibitor, whose mechanism of action is based on targeting aromatic recognition modules together with a unique Cα‐methylation β‐breakage strategy. We thank Tal Mazor for the graphical assistance with the cover.

magnified image
The tribological characteristics of phosphorylated 3‐aminopropyltriethoxysilane nanometer film
Authors: Li J. , Li X. Z.
Published: February 2009

Thin films deposited on the phosphonate 3‐aminopropyltriethoxysilane (APTES) self‐assembled monolayer (SAM) were prepared on the hydroxylated silicon substrate by a self‐assembling process from specially formulated solution. Chemical compositions of the films and chemical state of the elements were detected by X‐ray photoelectron spectrometry. The thickness of the films was determined with an ellipsometer, whereas the morphologies and nanotribological properties of the samples were analyzed by means of atomic force microscopy. As the results, the target film was obtained and reaction may have taken place between the thin films and the silicon substrate. It was also found that the thin films showed the lowest friction and adhesion followed by APTES‐SAM and phosphorylated APTES‐SAM, whereas silicon substrate showed high friction and adhesion. Microscale scratch/wear studies clearly showed that thin films were much more scratch/wear resistant than the other samples. The superior friction reduction and scratch/wear resistance of thin films may be attributed to low work of adhesion of nonpolar terminal groups and the strong bonding strength between the films and the substrate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Temperature‐sensitive poly(N‐tert‐butylacrylamide‐co‐acrylamide) hydrogels bonded on cotton fabrics by coating technique
Authors: Liu Shufang , Niu Jiarong , Gu Zhenya
Published: February 2009

Different from the conventional method of developing stimuli‐sensitive textiles by graft copolymerization of environmental responsive polymers onto the fabric, the coating technique was applied to bond temperature‐sensitive hydrogels with cotton fabric through chemical covalent in our work. A temperature‐sensitive linear copolymer of N‐tert‐butylacrylamide (NTBA) and acrylamide (AAm) was prepared in methanol. Then, the cotton fabrics were coated using an aqueous solution of this copolymer containing 1,2,3,4‐butanetertracarboxylic acid as a crosslinker and sodium hypophosphite (SHP) as a catalyst, followed by drying and curing. The surface of the cotton fabrics was bonded on more or less coatings of poly (NTBA‐co‐AAm) hydrogels, as verified by Fourier transform infrared spectroscopy and scanning electron microscopy images. The poly(NTBA‐co‐AAm) hydrogels‐coated fabrics exhibited temperature sensitive, and the temperature interval of the deswelling transition was higher than lower critical solution temperature of linear copolymer solution. The coated fabrics presented good water‐impermeable ability because of the swelling of hydrogels bonded, especially when the add‐on was as high as 14.14%. Environmental scanning electron microscopy images revealed that coating hydrogels swelled and covered on the surface as a barrier to prevent water from penetrating once the coated fabric came into contact with water. The findings demonstrate that the temperature‐sensitive hydrogels can be covalently bonded on the cotton fabrics by coating technique and the coated fabrics have potential on immersion fabrics. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanism of the droplet formation and stabilization in the aqueous two‐phase polymerization of acrylamide
Authors: Lü Ting , Shan Guorong
Published: February 2009

Aqueous two‐phase polymerization of acrylamide has been carried out in an aqueous solution of poly(ethylene glycol) initiated by ammonium persulfate. The chemical composition of the product was characterized by FTIR, and the droplet size distribution in the initial stage of the polymerization was followed by dynamic light scattering. On the basis of the evolution of polyacrylamide aqueous droplets size distribution and morphology at every stage, a new mechanism of droplet formation was proposed. The experimental phenomenon that the small droplets always existed in the process of polymerization and some irregular shape droplets were formed in the product of aqueous two phase polymerization could be successfully explained by the new mechanism. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Optimization of preparation conditions on the dielectric properties of polyaniline
Authors: Thomas Rinku M. , John Honey , Mathew K. T. , Joseph Rani , George K. E.
Published: February 2009

The dielectric response in the microwave field of polyaniline prepared at different temperatures and using different inorganic and organic dopants was studied. Chemical oxidative polymerization of aniline was done at low temperature (0–5°C), at room temperature, and at high (60°C) temperature using different inorganic dopants like HCl, HNO3, H2SO4, HClO4, etc. Polyaniline was also prepared with different organic dopants like camphor sulfonic acid, Toluene sulfonic acid, and Naphthalene sulfonic acid. All polymers formed were characterized using IR, TGA, DSC, and SEM, etc. The dielectric responses of all polymers are studied using cavity perturbation technique in the microwave field. The studies indicates that the polyaniline prepared with perchloric acid at room temperature shows higher conductivity and absorption coefficient compared with all other samples. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The changes of transesterification level in PET/PEN blends with the addition of PET–PEN copolymer
Authors: Ida Shin‐Ichiro , Yamamoto Hiroko , Ito Masayoshi
Published: February 2009

The extent of transesterification in poly(ethylene terephthalate) (PET)/poly(ethylene‐2,6‐naphthalate) (PEN) blends with the addition of PET–PEN copolymers was examined by DSC and 1H‐NMR measurements to evaluate the factor affecting the reaction level at a given temperature and time. Both block (P(ET‐block‐EN)) and random (P(ET‐ran‐EN)) copolymers were used as the copolymers. At a given treatment temperature and time, the level was increased by the addition of P(ET‐block‐EN) into PET/PEN blends. On the other hand, a reverse change was observed when P(ET‐ran‐EN) was mixed with PET/PEN blends. During the treatment, an inhomogeneous phase of the blends changed into the homogeneous one; however, the change showed little effect on the reaction level. The effects of molecular weight on the reaction level were also examined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Changes in northern Tanzania coral reefs during a period of increased fisheries management and climatic disturbance
Authors: McClanahan Tim R. , Muthiga Nyawira A. , Maina Joseph , Kamukuru Albogast T. , Yahya Saleh A.S.
Published: February 2009

Surveys of coral reefs in northern Tanzania were conducted in 2004/5 with the aim of comparing them over an∼8‐year period during a time of increased efforts at fisheries management and the 1998 El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) coral mortality event that caused 45% mortality in northern Tanzania and much of the Indian Ocean.

Changes associated with both management, its absence, and the ENSO were found but changes were generally small and ecological measures indicated stability or improvements over this period, particularly when compared with reports from much of the northern Indian Ocean.

Fisheries management in two areas increased the biomass of fish and benthic communities. A small fisheries closure (0.3 km2) displayed little change in the coral community but ecological conditions declined as measured by sea urchins and fish abundances. This change may be associated with its small size because similar changes were not measured in the large closure (28 km2).

The few sites without any increased management were still degraded and one site had experienced a population explosion of a pest sea urchin, Echinometra mathaei.

The lack of significant changes across this disturbance indicates that these reefs are moderately resilient to climate change and, therefore, a high priority for future conservation actions.

Copyright © 2009 John Wiley & Sons, Ltd.
Geochemistry as an aid in archaeological prospection and site interpretation: current issues and research directions
Authors: Oonk S. , Slomp C. P. , Huisman D. J.
Published: February 2009

Human habitation may significantly affect the chemical soil composition leading to enrichments and depletions of specific chemical elements and the formation of archaeological soils. Prospection and interpretation of sites by means of element analysis of soils requires appropriate and well‐tested geochemical methodologies. In this paper element analysis in archaeological prospection and site interpretation is briefly reviewed and three major unresolved issues are discussed: (i) how to distinguish archaeological chemical signals in soils from modern and geogenic signals; (ii) what role do geochemical processes play in the formation of archaeological soils; (iii) how to implement geochemical methods in archaeological research programmes. These issues are addressed with reference to the geochemical literature on retention and sequestration pathways of presumed anthropogenic elements in soils and analytical procedures. Based on the acquired knowledge, several directions for future research are proposed. Copyright © 2009 John Wiley & Sons, Ltd.
Geophysical investigation of the Environs of Rattin Castle Tower House, County Westmeath, Ireland
Authors: O'Rourke T. , Gibson P. J.
Published: February 2009

No visible archaeological features are today associated with Rattin Castle Tower House in County Westmeath, Ireland located near the boundary of the Pale, the area around Dublin and adjoining counties where English control prevailed. However, both magnetic and resistance data show that Rattin Castle was surrounded by a substantial bawn wall, which has since been removed. Interpretation of two‐dimensional resistivity shows a deep trench at the site of the bawn wall. A small (12 by 16 m) rectangular low‐resistance anomaly located outside the northern section of the bawn wall but connected to it, is interpreted as a possible gatehouse providing access to the castle. Less than 20 m from this anomaly, the course of an old military road is delineated by magnetic data but is seen most clearly on the resistance data where it is represented by two parallel low‐resistance anomalies 230 m long. This road is possibly older than the castle. Rattin is associated with an extensive network of subrectangular field boundaries and enclosures, most noticeably west of the castle. The presence of the military road, potential gatehouse, substantial bawn wall and geographical location all suggest that Rattin Castle was an important strategic fortification in Ireland. Copyright © 2009 John Wiley & Sons, Ltd.
Three‐dimensional resistivity probability tomography at the prehistoric site of grotta reali (Molise, Italy)
Authors: Compare Vincenzo , Cozzolino Marilena , Mauriello Paolo , Patella Domenico
Published: February 2009

A geoelectrical survey has been performed at the Mousterian (Palaeolithic) site of Grotta Reali (Molise Region, central Italy), which is one of the most important archaeological locations in the region, where Neanderthal fossils have been brought to light. An array of dipole–dipole profiles was designed in order to explore the nature of some archaeological levels found in a mostly fine‐grained waste matrix along the wall of a travertine open quarry, very close to the Grotta Reali, which is a natural cavity of karst origin. Data analysis utilized a three‐dimensional tomography approach based on the concept of occurrence probability of anomaly sources in the electrical resistivity distribution. The three‐dimensional probability tomography allowed the geometry of an occluded portion of the prehistoric cavity to be delineated, and a vertical, elongated high resistivity block to be fully imaged inside this part of the cavity. Subsequent excavations have confirmed the inner geometry of the cavity, and identified a travertine column correlating with the high‐resistivity block delineated by the three‐dimensional geoelectrical tomography. Copyright © 2009 John Wiley & Sons, Ltd.
Chemical Modification of Proteins at Cysteine: Opportunities in Chemistry and Biology
Authors: Chalker Justin M. , Bernardes Gonçalo J. L. , Lin Yuya A. , Davis Benjamin G.
Published: February 2009

Cys‐tematic modification: Cysteine is a versatile amino acid for selective chemical modification of proteins. Both chemical and biological innovations made possible by cysteine modification are highlighted in this Focus Review.

magnified image

Chemical modification of proteins is a rapidly expanding area in chemical biology. Selective installation of biochemical probes has led to a better understanding of natural protein modification and macromolecular function. In other cases such chemical alterations have changed the protein function entirely. Additionally, tethering therapeutic cargo to proteins has proven invaluable in campaigns against disease. For controlled, selective access to such modified proteins, a unique chemical handle is required. Cysteine, with its unique reactivity, has long been used for such modifications. Cysteine has enjoyed widespread use in selective protein modification, yet new applications and even new reactions continue to emerge. This Focus Review highlights the enduring utility of cysteine in protein modification with special focus on recent innovations in chemistry and biology associated with such modifications.
Diurnal and semidiurnal rainfall cycles during the rain season in SW Amazonia, observed via rain gauges and estimated using S‐band radar
Authors: Santos e Silva Cláudio Moisés , Gielow Ralf , de Freitas Saulo Ribeiro
Published: February 2009

The rainfall field estimated by an S‐band radar was evaluated with rain gauges network measurements during the Tropical Rainfall Measuring Mission and Large‐Scale Biosphere–Atmosphere Experiment in Amazonia (TRMM‐LBA), then the daily variability associated with the presence (absence) of the South Atlantic convergence zone (SACZ) were studied. The results showed the high spatial variability of the rainfall over southwest (SW) Amazonia and suggest that local mechanisms (topography and/or local circulations induced by contrast of vegetation) may be associated with heavy rainfall episodes; moreover, it was possible to observe the squall line influence on the diurnal and semidiurnal cycles. Copyright © 2009 Royal Meteorological Society
Deciphering the role of Shh signaling in axial defects produced by ethanol exposure
Authors: Loucks Evyn J. , Ahlgren Sara C.
Published: February 2009

BACKGROUND: The phenotype of embryos exposed to ethanol is complex and likely due to multiple alterations in developmental pathways. We have previously demonstrated that Sonic hedgehog signaling (Shh‐s) was reduced in both chicken and zebrafish embryos when exposed to ethanol. METHODS: There are many tissues affected by embryonic ethanol exposure, and in this article we explore the development of axial tissues, using zebrafish embryos. We then compare these effects to the phenotypes produced by exposure to two drugs that also inhibit Shh‐s: cyclopamine and forskolin. RESULTS: We found alterations in the development of the notochord and somites produced by all three compounds, although only ethanol produced developmental delay of epiboly. Upon observation of early developing embryos, muscle pioneer cells were completely lost in cyclopamine‐treated embryos, and reduced, but less so, in embryos treated with forskolin and ethanol. Ethanol treatment produced a dose‐dependent reduction in total body length that may be linked to epiboly delay seen earlier during development. Despite the differences between cyclopamine and forskolin, we found that shh mRNA injection rescued the short body length, the alteration in somite shape, and the cyclopia produced by ethanol exposure. CONCLUSIONS: Taken together, each teratogen produced a unique set of phenotypic changes in the body axis, suggesting that each compound affects Shh‐s and also produces a distinctive set of molecular alterations. However, addition of exogenous Shh to ethanol treated zebrafish prevented many of the gross physical phenotypes, suggesting that the suppression of Shh‐s is one of the major effects of ethanol exposure. Birth Defects Research (Part A), 2009. © 2009 Wiley‐Liss, Inc.