bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconstructing evolution: Gene transfer from plastids to the nucleus
Authors: Bock Ralph , Timmis Jeremy N.
Published: May 2008

During evolution, the genomes of eukaryotic cells have undergone major restructuring to meet the new regulatory challenges associated with compartmentalization of the genetic material in the nucleus and the organelles acquired by endosymbiosis (mitochondria and plastids). Restructuring involved the loss of dispensable or redundant genes and the massive translocation of genes from the ancestral organelles to the nucleus. Genomics and bioinformatic data suggest that the process of DNA transfer from organelles to the nucleus still continues, providing raw material for evolutionary tinkering in the nuclear genome. Recent reconstruction of these events in the laboratory has provided a unique tool to observe genome evolution in real time and to study the molecular mechanisms by which plastid genes are converted into functional nuclear genes. Here, we summarize current knowledge about plastid‐to‐nuclear gene transfer in the context of genome evolution and discuss new insights gained from experiments that recapitulate endosymbiotic gene transfer in the laboratory. BioEssays 30:556–566, 2008. © 2008 Wiley Periodicals, Inc.
Modeling the circadian clock: From molecular mechanism to physiological disorders
Authors: Leloup Jean‐Christophe , Goldbeter Albert
Published: May 2008

Based on genetic and biochemical advances on the molecular mechanism of circadian rhythms, a computational model for the mammalian circadian clock is used to examine the dynamical bases of circadian‐clock‐related physiological disorders in humans. Entrainment by the light–dark cycle with a phase advance or a phase delay is associated with the Familial advanced sleep phase syndrome (FASPS) or the Delayed sleep phase syndrome (DSPS), respectively. Lack of entrainment corresponding to the occurrence of quasiperiodic oscillations with or without phase jump can be associated with the non‐24 h sleep–wake syndrome. In the close vicinity of the entrainment domain, the model uncovers the possibility of infradian oscillations of very long period. Perturbation in the form of chronic jet lag, as used in mice, prevents entrainment of the circadian clock and results in chaotic or quasiperiodic oscillations. It is important to clarify the conditions for entrainment and for its failure because dysfunctions of the circadian clock may lead to physiological disorders, which pertain not only to the sleep–wake cycle but also to mood and cancer. BioEssays 30:590–600, 2008. © 2008 Wiley Periodicals, Inc.
Control of epithelial cell structure and developmental fate: Lessons from Helicobacter pylori
Authors: Mimuro Hitomi , Berg Douglas E. , Sasakawa Chihiro
Published: May 2008

Valuable insights into eukaryotic regulatory circuits can emerge from studying interactions of bacterial pathogens such as Helicobacter pylori with host tissues. H. pylori uses a type IV secretion system (T4SS) to deliver its CagA virulence protein to epithelial cells, where much of it becomes phosphorylated. CagA's phosphorylated and non‐phosphorylated forms each interact with host regulatory proteins to alter cell structure and cell fate. Kwok and colleagues1 showed that CagA destined for phosphorylation is delivered using host integrin as receptor and H. pylori's CagL protein as an integrin‐specific adhesin, and that CagL–integrin‐binding activates the kinase cascade responsible for CagA phosphorylation. This research contributes to understanding infectious disease and the control of cell fates. BioEssays 30:515–520, 2008. © 2008 Wiley Periodicals, Inc.
α‐Lactosylceramide as a Novel “Sugar‐Capped” CD1d Ligand for Natural Killer T Cells: Biased Cytokine Profile and Therapeutic Activities
Authors: Zhang Wenpeng , Zheng Xincheng , Xia Chengfeng , Perali Ramu Sridhar , Yao Qingjia , Liu Yang , Zheng Pan , Wang Peng George
Published: May 2008

The invariant natural killer T cells (iNKT) cells have emerged as an important regulator of immunity to infection, cancer, and autoimmune diseases. They can be activated by glycolipids that bind to CD1d. The most effective iNKT ligand reported to date is α‐galactosylceramide (α‐GalCer), which stimulates iNKT cells to secrete both Th‐1 and Th‐2 cytokines. Indiscriminate induction of both types of cytokines could limit the therapeutic potential of iNKT ligands, as Th‐1 and Th‐2 cytokines play different roles under physiological and pathological conditions. Therefore, a ligand with a biased cytokine‐release profile would be highly desirable. Here, we report the synthesis and biological activity of α‐lactosylceramide (α‐LacCer). Our data demonstrate that α‐LacCer can stimulate iNKT cells to proliferate and release cytokines, both in vitro and in vivo. Interestingly, while α‐LacCer is approximately 1000‐times less efficient than α‐GalCer in inducing Th‐1 cytokines, it is as potent as α‐GalCer in the induction of Th‐2 cytokines; therefore, α‐LacCer is a novel compound that induces a biased cytokine release. Processing by β‐glycosidase was critical for α‐LacCer activity. Moreover, in vivo experiments suggest that α‐LacCer is at least as potent as α‐GalCer in the treatment of tumors and experimental autoimmune encephalomyelitis.
Generation of an Aromatic Amide‐Derived Phosphane (Aphos) Library by Self‐Assisted Molecular Editing and Applications of Aphos in Room‐Temperature Suzuki–Miyaura Reactions
Authors: Dai Wei‐Min , Li Yannian , Zhang Ye , Yue Congyong , Wu Jinlong
Published: May 2008

Aromatic amide‐derived phosphanes (Aphos) are hemilabile P,O‐coordinating ligands, which, when combined with a Pd precursor, yield a promising precatalyst system for Suzuki–Miyaura cross‐coupling reactions. A focused library of Aphos ligands has been constructed for structural optimization, with the target of improving catalytic efficacy. By using microwave irradiation at accurately regulated temperature, an expeditious and reproducible one‐pot synthesis and screening protocol was designed and experimentally validated. The success is based on a unique self‐assisted molecular editing (SAME) process in which both the substrate and the product molecules catalyze formation of the product. Thus, starting from a 4‐chlorobenzamide‐derived Aphos as the substrate, parallel reactions with a selected set of arylboronic acids, in the absence of an added external phosphane ligand to Pd, produced a family of structurally edited Aphos ligands. The resultant reaction mixture containing the new Aphos, the Pd species, and the base could be used for in situ screening of the Aphos efficacy in a reference Suzuki–Miyaura coupling reaction. The structures of all Aphos ligands were characterized by 31P NMR spectroscopy and their catalytic profiles in the reference reaction were evaluated by HPLC analysis. These data allowed the identification of an efficient Aphos ligand, capable of promoting room‐temperature Suzuki–Miyaura coupling of unactivated and sterically hindered aryl chlorides with arylboronic acids under mildly basic conditions.
Fine needle aspiration of head and neck masses in the operating room: Accuracy and potential benefits
Authors: Arabi Haitham , Yousef Nida , Bandyopadhyay Sudeshna , Feng Jining , Yoo George H. , Al‐Abbadi Mousa A.
Published: May 2008

Fine needle aspiration (FNA) in the operating room is a convenient optional diagnostic approach. Our objective of this study was to evaluate the accuracy and study the potential benefits of fine needle aspiration in the operating room.

Retrospective review of all intraoperative FNA that were requested and performed by pathologists over 20‐month period was carried out. Immediate smears were interpreted by the cytopathology team after staining with Diff Quik stain. All cases were reviewed and correlation with subsequent tissue diagnosis was done. Accuracy was calculated and potential benefits were discussed. The number of aspirates was 32. Adequate material for immediate and final interpretation was achieved in 31 cases (sensitivity 97%). In 20 cases (63%), malignancy was diagnosed while a benign diagnosis was rendered in 12 (37%). All cases had a follow up tissue diagnosis. No false–positive cases were identified (specificity 100%). The information gained from this approach was considered helpful to the surgeons. We concluded that FNA of head and neck masses in the operating room is an accurate and sensitive diagnostic approach. The service provides helpful information to surgeons and is an additional optional diagnostic approach. Diagn. Cytopathol. 2008;36:369–374. © 2008 Wiley‐Liss, Inc.
Indications for thyroid FNA and pre‐FNA requirements: A synopsis of the National Cancer Institute Thyroid Fine‐Needle Aspiration State of the Science Conference
Authors: Cibas Edmund S. , Alexander Erik K. , Benson Carol B. , de Agustín Pedro Patricio , Doherty Gerard M. , Faquin William C. , Middleton William D. , Miller Theodore , Raab Stephen S. , White Matthew L. , Mandel Susan J.
Published: May 2008

The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine‐Needle Aspiration (FNA) State of the Science Conference on October 22–23, 2007 in Bethesda, MD. The 2‐day meeting was accompanied by a permanent informational website and several on‐line discussions between May 1 and December 15, 2007 (http://thyroidfna.cancer.gov). This document summarizes the indications for performing an FNA of a nodule discovered by physical examination or an imaging study; the indications for using ultrasound versus palpation for guidance when performing a thyroid FNA; the issues surrounding informed consent for thyroid FNA; and the information required on a requisition form that accompanies a thyroid FNA specimen. (http://thyroidfna.cancer.gov/pages/info/agenda/) Diagn. Cytopathol. 2008;36:390–399. © 2008 Wiley‐Liss, Inc.
Training, credentialing and re‐credentialing for the performance of a thyroid FNA: A synopsis of the National Cancer Institute Thyroid Fine‐Needle Aspiration State of the Science Conference
Authors: Ljung Britt‐Marie E. , Langer Jill , Mazzaferri Ernest L. , Oertel Yolanda C. , Wells Samuel A. , Waisman Jerry
Published: May 2008

The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine‐Needle Aspiration (FNA) State of the Science Conference on October 22–23, 2007 in Bethesda, MD. The 2‐day meeting was accompanied by a permanent informational website and several on‐line discussion periods between May 1 and December 15, 2007 (http://thyroidfna.cancer.gov). This document summarizes matters regarding training for the performance of thyroid FNA via palpation; training for the performance of thyroid FNA via ultrasound imaging, and credentialing/re‐credentialing for the performance of a thyroid FNA. (http://thyroidfna.cancer.gov/pages/info/agenda/) Diagn. Cytopathol. 2008;36:400–406. © 2008 Wiley‐Liss, Inc.
Post‐thyroid FNA testing and treatment options: A synopsis of the National Cancer Institute Thyroid Fine Needle Aspiration State of the Science Conference
Authors: Layfield Lester J. , Abrams Jacki , Cochand‐Priollet Beatrix , Evans Doug , Gharib Hossein , Greenspan Frank , Henry Michael , LiVolsi Virginia , Merino Maria , Michael Claire W. , Wang Helen , Wells Samuel A.
Published: May 2008

The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine Needle Aspiration (FNA) State of the Science Conference on October 22–23, 2007 in Bethesda, MD. The 2‐day meeting was accompanied by a permanent informational Web site and several on‐line discussion periods between May 1 and December 15, 2007 (http://thyroidfna.cancer.gov). This document addresses follow‐up procedures and therapeutic options for suggested diagnostic categories. Follow‐up options for “nondiagnostic” and “benign” thyroid aspirates are given. The value of ultrasound examination in the follow‐up of “nondiagnostic” and “benign” thyroid aspirates is discussed. Ultrasound findings requiring reaspiration or surgical resection are described as are the timing and length of clinical and ultrasonographic surveillance for cytologically “benign” nodules. Options for surgical intervention are given for the diagnostic categories of “atypical/borderline,” “follicular neoplasm,” “suspicious for malignancy” and “malignant” (http://thyroidfna.cancer.gov/pages/info/agenda/). Diagn. Cytopathol. 2008;36:442–448. © 2008 Wiley‐Liss, Inc.
A Tetragonal Core with Asymmetric Iron Environments Supported Solely by Bis(μ‐OH){μ‐(O–H···O)} Bridging and Terminal Pyridine Amide (N, O) Coordination: A New Member of the Tetrairon(III) Family
Authors: Singh Akhilesh K. , Jacob Wilson , Boudalis Athanassios K. , Tuchagues Jean‐Pierre , Mukherjee Rabindranath
Published: May 2008

Room‐temperature aerobic reaction of [Fe(MeCN)4][ClO4]2 with 1,3‐bis(2‐pyridinecarboxamido)propane (H2bpp) yields the tetrairon(III) complex [Fe4(H2bpp)4(μ‐OH)2(μ‐OHO)][ClO4]7·2H2O·xMeCN (1·xMeCN, 0 ≤ x ≤ 3). Crystal structure determination reveals that 1·3MeCN is a new member of the tetrairon(III) family, bridged solely by two hydroxido ligands and a localized {O–H···O}3– bridging unit. The properties of the “tetragonal” core [Fe4(μ‐OH)2{μ‐(O–H···O)}]7+ have been investigated by variable‐temperature magnetic and Mössbauer spectroscopic measurements. Successful modeling of the data has revealed asymmetric iron environments and three types of magnetic exchange interactions [through μ‐OH and μ‐O/μ‐OH of μ‐(O–H···O) bridges]. This tetragonal core is a valuable addition to the tetrairon(III) cluster family from inorganic and bioinorganic perspectives.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
The Cyclooligomerisation of Acetylene at Metal Centres
Authors: Xu Rong , Winget Paul , Clark Timothy
Published: May 2008

Density‐functional theory (DFT) and QCISD(T) calculations have been used to investigate the mechanism of cyclodimerisation and cyclotrimerisation of acetylene at a cyclopentadienyl‐CoI centre. In contrast to earlier investigations, we find that the most favourable mechanism for the formation of benzene involves the insertion of an acetylene molecule into a Co–C bond of the well known cobaltacyclopentadienyl intermediate. The product of this reaction then undergoes very facile ring‐closure to benzene. This mechanism is found to be more favourable than the concerted Diels–Alder path, which is the highest in energy of the three mechanisms considered. The remaining reaction path involves initial addition of an acetylene molecule to the cyclopentadienyl ligand followed by rearrangement to give a 1,3,5‐hexatrien‐1‐ylcyclopentane ligand system, which cleaves to give benzene and cyclopentadienyl ligands. Spin crossovers between the singlet and triplet states are found for the ring‐closure of the cobaltacyclopentadienyl intermediate to give a cyclobutadiene complex and for the concerted Diels–Alder process. These spin crossovers and the reaction mechanisms in general are rationalised in terms of the concept of electron‐transfer catalysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Iridium‐Catalyzed Hydrogenation of β‐Dehydroamino Acid Derivatives Using Monodentate Phosphoramidites
Authors: Enthaler Stephan , Erre Giulia , Junge Kathrin , Schröder Kristin , Addis Daniele , Michalik Dirk , Hapke Marko , Redkin Dmitry , Beller Matthias
Published: May 2008

The iridium‐catalyzed asymmetric hydrogenation of 13 different β‐dehydroamino acid derivatives to give optically active β‐amino acid esters has been examined. Readily accessible monodentate octahydrobinaphthol‐based phosphoramidites were used as chiral ligands. Good to excellent enantioselectivities and yields were obtained for the E isomers, whereas poorer catalyst performance was found for the Z isomers. Importantly, to obtain high enantioselectivity, substitution at the 3,3′‐positions of the ligands was necessary. Enantioselectivities of up to 94 % ee were achieved under optimized conditions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
The Thread & Cut Method: Syntheses of Molecular Knot Precursors
Authors: Fenlon Edward E. , Ito Brandon R.
Published: May 2008

A novel approach to molecular knots is described. This method may allow access to smaller and more complex knots. Two knot precursors, 1a and 1b, are efficiently prepared in overall yields of 9.6 % and 8.7 %, respectively. The convergent six‐step syntheses utilize Fréchet‐type etherifications, alkyne/azide click cycloadditions, and bis‐macrolactonizations.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Morphological analysis of the Sudd region using land survey and remote sensing data
Authors: Petersen G. , Sutcliffe J. V. , Fohrer N.
Published: May 2008

An analysis of the vast wetland of the Sudd swamps in southern Sudan was designed to assess and describe interdependencies between morphology and hydrology. Findings based on field survey and remote sensing data include an assessment of the effect of ground slopes and morphological features on spill and flooding of the seasonally flooded grasslands. Through bathymetric surveys and analysis of Landsat images, depth profiles and cross‐sectional depth and flow distributions were established. Data from remote sensing, field survey and historical sources were correlated and correction factors established; the SRTM was found to be partly unsuitable for further assessments. Further analysis of remote sensing data was used to investigate the Sudd's inland delta as well as the question of spill into the Bahr el Ghazal basin. Copyright © 2008 John Wiley & Sons, Ltd.
A low‐dimensional physically based model of hydrologic control of shallow landsliding on complex hillslopes
Authors: Talebi Ali , Uijlenhoet Remko , Troch Peter A.
Published: May 2008

Hillslopes have complex three‐dimensional shapes that are characterized by their plan shape, profile curvature of surface and bedrock, and soil depth. To investigate the stability of complex hillslopes (with different slope curvatures and plan shapes), we combine the hillslope‐storage Boussinesq (HSB) model with the infinite slope stability method. The HSB model is based on the continuity and Darcy equations expressed in terms of storage along the hillslope. Solutions of the HSB equation account explicitly for plan shape by introducing the hillslope width function and for profile curvature through the bedrock slope angle and the hillslope soil depth function. The presented model is composed of three parts: a topography model conceptualizing three‐dimensional soil mantled landscapes, a dynamic hydrology model for shallow subsurface flow and water table depth (HSB model) and an infinite slope stability method based on the Mohr–Coulomb failure law. The resulting hillslope‐storage Boussinesq stability model (HSB‐SM) is able to simulate rain‐induced shallow landsliding on hillslopes with non‐constant bedrock slope and non‐parallel plan shape. We apply the model to nine characteristic hillslope types with three different profile curvatures (concave, straight, convex) and three different plan shapes (convergent, parallel, divergent). In the presented model, the unsaturated storage has been calculated based on the unit head gradient assumption. To relax this assumption and to investigate the effect of neglecting the variations of unsaturated storage on the assessment of slope stability in the transient case, we also combine a coupled model of saturated and unsaturated storage and the infinite slope stability method. The results show that the variations of the unsaturated zone storage do not play a critical role in hillslope stability. Therefore, it can be concluded that the presented dynamic slope stability model (HSB‐SM) can be used safely for slope stability analysis on complex hillslopes. Our results show that after a certain period of rainfall the convergent hillslopes with concave and straight profiles become unstable more quickly than others, whilst divergent convex hillslopes remain stable (even after intense rainfall). In addition, the relation between subsurface flow and hillslope stability has been investigated. Our analyses show that the minimum safety factor (FS) occurs when the rate of subsurface flow is a maximum. In fact, by increasing the subsurface flow, stability decreases for all hillslope shapes. Copyright © 2008 John Wiley & Sons, Ltd.
Consequences of short‐term changes in coastal processes: a case study
Authors: Phillips M. R.
Published: May 2008

In 1997–98, unique critical beach erosion led to structural failure along the Penarth, South Wales, UK coastline and anthropogenic activities, such as the construction of the Cardiff Bay Barrage and offshore marine aggregate dredging, were suggested as causes. The time‐frame of significant erosion was between 1995 and 1997 and forcing agents (extreme sea level and wind direction) and shoreline indicators (mean beach level and MHW) were analysed in order to assess change. Water level analysis showed that although there was no significant difference between actual and predicted mean sea levels, extreme sea levels at that time were significantly higher (t = 3·305; d.f. = 8; p < 0·05). Three wind direction analyses (annual mean, mean annual maximum gust and mean annual maximum gust ≥28 kn) between 1995 and 1997 also showed significant differences (p < 0·05). All comprised more easterly components which meant they approached the beach from the sea. Furthermore, gusts ≥28 kn from the northeast quadrant, that is, 0° to 90° true, were significantly more frequent during these years (t = 3·674; d.f. = 8; p < 0·01). Justification of statistical significances was established and there was supporting evidence of unusual meteorological conditions at that time. Relationships showed correlation between forcing agents (extreme sea level and wind direction) and shoreline indicators (mean beach level and Mean High Water). Furthermore, regression analysis showed winds from the northeast quadrant resulted in steeper longshore gradients, as a consequence of beach material loss. Therefore, it was concluded that the critical erosion of Penarth beach between 1995 and 1997 was caused by increased wave attack from the northeast and southeast quadrants, generated by unique significant changes in wind direction and extreme sea levels. Copyright © 2008 John Wiley & Sons, Ltd.
Bank erosion and channel width change in a tropical catchment
Authors: Bartley Rebecca , Keen Rex J. , Hawdon Aaron A. , Hairsine Peter B. , Disher Mark G. , Kinsey‐Henderson A. E.
Published: May 2008

Catchment sediment budget models are used to predict the location and rates of bank erosion in tropical catchments draining to the Great Barrier Reef lagoon, yet the reliability of these predictions has not been tested due to a lack of measured bank erosion data. This paper presents the results of a 3 year field study examining bank erosion and channel change on the Daintree River, Australia. Three different methods were employed: (1) erosion pins were used to assess the influence of riparian vegetation on bank erosion, (2) bench‐marked cross‐sections were used to evaluate annual changes in channel width and (3) historical aerial photos were used to place the short term data into a longer temporal perspective of channel change (1972–2000). The erosion pin data suggest that the mean erosion rate of banks with riparian vegetation is 6·5 times (or 85%) lower than that of banks without riparian vegetation. The changes measured from cross‐section surveys suggest that channel width has increased by an average of 0·74 (±0·47) m a−1 over the study period (or ∼0·8% yr−1). The aerial photo results suggest that over the last 30 years the Daintree River has undergone channel contraction of the order of 0·25 m a−1. The cross‐section data were compared against modelled SedNet bank erosion rates, and it was found that the model underestimated bank erosion and was unable to represent the variable erosion and accretion processes that were observed in the field data. The reach averaged bank erosion rates were improved by the inclusion of locally derived bed slope and discharge estimates; however, the results suggest that it will be difficult for catchment scale sediment budget models to ever accurately predict the location and rate of bank erosion due to the variation in bank erosion rates in both space and time. Copyright © 2008 John Wiley & Sons, Ltd.
The potential of digital filtering of generic topographic data for geomorphological research
Authors: Milledge D. G. , Lane S. N. , Warburton J.
Published: May 2008

High resolution terrain models generated from widely available Interferometric Synthetic Aperture Radar (IfSAR) and digital photogrammetry are an exciting resource for geomorphological research. However, these data contain error, necessitating pre‐processing to improve their quality. We evaluate the ability of digital filters to improve topographic representation, using: (1) a Gaussian noise removal filter; (2) the proprietary filters commonly applied to these datasets; and (3) a terrain sensitive filter, similar to those applied to laser altimetry data. Topographic representation is assessed in terms of both absolute accuracy measured with reference to independent check data and derived geomorphological variables (slope, upslope contributing area, topographic index and landslide failure probability) from a steepland catchment in northern England. Results suggest that proprietary filters often degrade or fail to improve precision. A combination of terrain sensitive and Gaussian filters performs best for both IfSAR and digital photogrammetry datasets, improving the precision of photogrammetry digital elevation models (DEMs) by more than 50 per cent relative to the unfiltered data. High‐frequency noise and high‐magnitude gross errors corrupt geomorphological variables derived from unfiltered photogrammetry DEMs. However, a terrain sensitive filter effectively removes gross errors and noise is minimized using a Gaussian filter. These improvements propagate through derived variables in a landslide prediction model, to reduce the area of predicted instability by up to 29 per cent of the study area. Interferometric Synthetic Aperture Radar is susceptible to removal of topographic detail by oversmoothing and its errors are less sensitive to filtering (maximum improvement in precision of 5 per cent relative to the raw data). Copyright © 2008 John Wiley and Sons, Ltd.
Avulsion regimes in southeast Texas rivers
Authors: Phillips Jonathan D.
Published: May 2008

Avulsions – relatively sudden changes in course, or establishment of new anabranches – are an important process in alluvial rivers. Their key role in floodplain construction and alluvial architecture, and the general conditions favouring avulsions, are well known. However, avulsion processes and evolution, and the factors controlling avulsion regimes, are poorly understood. In the southeast Texas coastal plain, where avulsions are common features of the river valleys, avulsions were studied on the lower Brazos, Navasota, Trinity, Neches and Sabine rivers using a combination of aerial imagery, digital elevation models and field surveys. Avulsions have important influences on the surface morphology and contemporary processes in all five rivers. Features associated with avulsions are active and distinct throughout the study area, and all the rivers have experienced geologically (if not historically) recent avulsions. However, no two of the study rivers have the same contemporary avulsion regime. First‐order differences in avulsion style are controlled by the stage of valley filling, and within the three rivers characterized by an unfilled incised valley, antecedent morphology associated with late Quaternary and Holocene coastal and fluvial‐deltaic processes accounts for the major differences. In the Navasota (27 avulsions in 185 km) and Neches (21 in 340 km) rivers, subchannels associated with avulsions exist in all stages of development from active to infilled, and some have occurred in recent decades. The other rivers have fewer avulsions, but both the Sabine and Trinity have experienced historic channel shifts. Only the Brazos River has experienced no avulsions within the past c. 300 years. Results show that even within a region of similar environmental controls and geological history local variations in inherited morphology can result in different avulsion regimes. Copyright © 2008 John Wiley & Sons, Ltd.
A comparison of predictive methods in modelling the distribution of periglacial landforms in Finnish Lapland
Authors: Marmion Mathieu , Hjort Jan , Thuiller Wilfried , Luoto Miska
Published: May 2008

This study compares the predictive accuracy of eight state‐of‐the‐art modelling techniques for 12 landforms types in a cold environment. The methods used are Random Forest (RF), Artificial Neural Networks (ANN), Generalized Boosting Methods (GBM), Generalized Linear Models (GLM), Generalized Additive Models (GAM), Multivariate Adaptive Regression Splines (MARS), Classification Tree Analysis (CTA) and Mixture Discriminant Analysis (MDA). The spatial distributions of 12 periglacial landforms types were recorded in sub‐Arctic landscape of northern Finland in 2032 grid squares at a resolution of 25 ha. First, three topographic variables were implemented into the eight modelling techniques (simple model), and then six other variables were added (three soil and three vegetation variables; complex model) to reflect the environmental conditions of each grid square. The predictive accuracy was measured by two methods: the area under the curve (AUC) of a receiver operating characteristic (ROC) plot, and the Kappa index (κ), based on spatially independent model evaluation data. The mean AUC values of the simple models varied between 0·709 and 0·796, whereas the AUC values of the complex model ranged from 0·725 to 0·825. For both simple and complex models GAM, GLM, ANN and GBM provided the highest predictive performances based on both AUC and κ values. The results encourage further applications of the novel modelling methods in geomorphology. Copyright © 2008 John Wiley & Sons, Ltd.
When Humanity Began to Settle Down
Authors: Schmidt Klaus
Published: May 2008

Paths to the early history of humanity: At the Göbekli Tepe in Anatolia, archaeologists are uncovering unique Stone Age monuments. They are thereby contributing to a new understanding of settlement history and of incipient agriculture
A Balancing Act
Authors: Schaeffer Magdalena
Published: May 2008

How the physicist and two‐time mother Elisa Resconi combines science and family
The Secrets of the “Glass Mountain”
Authors: Heide Klaus
Published: May 2008

Glasses occur even where they are least expected – in nature. The study of their mechanisms of formation and their characteristics is of considerable importance for the creation of new materials and for technical applications
Precarious Success in the Humanities
Authors: Gehrke Hans‐Joachim
Published: May 2008

The DFG's funding initiative has given this discipline a boost – but budget cuts and the principle of exploitation remain a threat
Where Science Builds Bridges
Authors: Streier Eva‐Maria
Published: May 2008

Excavation site Wiskiauten: A team of Russian and German archaeologists dig near Kaliningrad in former East Prussia
The Emperor's New Colonies
Authors: Schmidt Wilhelm R.
Published: May 2008

The Colonial Picture Archive in Frankfurt offers a unique pictorial record of German colonial history. For many years the collection was virtually forgotten. However, following painstaking description and digitalisation, the photo documents are now available on the Internet to researchers in Germany and abroad
Seasonal waves on glaciers
Authors: Hewitt I. J. , Fowler A. C.
Published: May 2008

Seasonal waves accompanying annual changes in the sliding velocity of ice travel down glacier at speeds much faster than the ice itself. A simple explanation for these waves in terms of the passage of a pressure wave through the subglacial drainage system is given. Drainage by both distributed and localized systems is explored, with the sliding velocity governed by a dependence on the effective pressure. Waves are caused by drainage through a slow distributed system, but may be damped if this is well connected to an efficient channelized system. A possible connection between these waves and high velocity spring events is discussed. Copyright © 2008 John Wiley & Sons, Ltd.
Elevated oxidative stress and DNA damage and repair levels in urinary bladder carcinomas associated with schistosomiasis
Authors: Salim Elsayed I. , Morimura Keiichirou , Menesi Ahmed , El‐Lity Mohammed , Fukushima Shoji , Wanibuchi Hideki
Published: May 2008

To cast light on mechanisms underlying development of urothelial carcinomas (UCs) of the urinary bladder associated with Schistosomiasis, we immunohistochemically analyzed the relationship between oxidative stress markers, DNA single strand breaks (ssDNA) which could also measure the levels of base damage and apoptosis in DNA, and expression of DNA repair genes with levels of nitric oxide synthases in bladder carcinomas of Egyptian patients with or without Schistosoma hematobium infection. Marked elevation of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) levels was found in squamous cell carcinomas and UCs associated with Schistosomiasis when compared with non‐Schistosomal carcinomas. This was accompanied by strong over expression of the DNA‐repair genes, 8‐oxoguanine‐DNA‐glycosylase and apurinic/apyrimidinic endonuclease, as well as increased formation levels of ssDNA. Expression levels of inducible nitric oxide synthase (iNOS) which is known to be indirectly related to oxidative stress was higher in Schistosomal than in the non‐Schistosomal carcinomas. However, expression of endothelial nitric oxide synthase was slightly stronger in non‐Schistosomal than in the Schistosomal carcinomas. In conclusion, these findings suggest a strong correlation between Schistosoma haematobium infection and increased levels of oxidative stress accompanied by a continuous DNA damage and repair in UCs, all directly correlating with elevated iNOS. © 2008 Wiley‐Liss, Inc.
All cause mortality and incidence of cancer in workers in bauxite mines and alumina refineries
Authors: Fritschi Lin , Hoving Jan Lucas , Sim Malcolm R. , Del Monaco Anthony , MacFarlane Ewan , McKenzie Dean , Benke Geza , de Klerk Nicholas
Published: May 2008

Bauxite is a reddish clay that is refined to produce alumina, which is then reduced to aluminium. There have been studies examining the health of workers in aluminium smelters, but not workers in bauxite mining and alumina refining. A cohort of employees of 1 large aluminium company since 1983 was assembled (n = 6,485, 5,828 men). Deaths and incident cancers to 2002 were ascertained by linkage to national and state cancer and death registries. SIRs and SMRs were calculated compared to national rates standardizing for calendar year, sex and 5‐year age group. The mortality from all causes (SMR 0.68, 95% CI: 0.60–0.77), and from circulatory and respiratory diseases, all cancers combined and injury in the male cohort were lower than in the Australian male population and were similar across work groups and with duration of employment. The only significant increased mortality risk was from pleural mesothelioma. The incidence of all cancers combined was similar to the Australian rate. The cohort had a lower risk of incident lymphohaematopoietic cancer (SIR 0.50, 95% CI: 0.31–0.88) and a higher risk of melanoma (SIR 1.30, 95% CI: 1.00–1.69) although no dose‐responses were seen. There was also an increased risk of mesothelioma (SIR 3.49, 95% CI: 1.82–6.71), which was associated with exposures outside the aluminium industry. This study is the first to examine cancer and mortality amongst workers in bauxite mines and alumina refineries and found little evidence for increased cancer incidence or mortality in these workers. © 2008 Wiley‐Liss, Inc.
Contributions of the mother–infant relationship to dissociative, borderline, and conduct symptoms in young adulthood
Authors: Lyons‐Ruth Karlen
Published: May 2008

Recent high‐risk longitudinal studies have documented a unique contribution of the quality of the early mother–child relationship to diverse forms of psychopathology in young adulthood, even with family economic status, later traumatic experiences, and some genetic factors controlled. In addition, measures of attachment‐related deviations in caregiver–infant interaction predict more than measures of infant attachment behavior alone. This article reviews those findings in the context of cross‐disciplinary thinking on the importance of shared subjectivities in human evolution and development and in the context of recent studies beginning to map the intersection between processes of interaction and the development of the child's propensities to share mental states with others.
Tethering a laminin peptide to a crosslinked collagen scaffold for biofunctionality
Authors: Damodaran Gopinath , Collighan Russell , Griffin Martin , Pandit Abhay
Published: May 2008

Cell adhesion peptide regulates various cellular functions like proliferation, attachment, and spreading. The cellular response to laminin peptide (PPFLMLLKGSTR), a motif of laminin‐5 α3 chain, tethered to type I collagen, crosslinked using microbial transglutaminase (mTGase) was investigated. mTGase is an enzyme that initiates crosslinking by reacting with the glutamine and lysine residues on the collagen fibers stabilizing the molecular structure. In this study that tethering of the laminin peptide in a mTGase crosslinked collagen scaffold enhanced cell proliferation and attachment. Laminin peptide tethered crosslinked scaffold showed unaltered cell morphology of 3T3 fibroblasts when compared with collagen and crosslinked scaffold. The triple helical structure of collagen remained unaltered by the addition of laminin peptide. In addition a dose‐dependent affinity of the laminin peptide towards collagen was seen. The degree of crosslinking was measured by amino acid analysis, differential scanning calorimeter and fourier transform infrared spectroscopy. Increased crosslinking was observed in mTGase crosslinked group. mTGase crosslinking showed higher shrinkage temperature. There was alteration in the fibrillar architecture due to the crosslinking activity of mTGase. Hence, the use of enzyme‐mediated linking shows promise in tethering cell adhesive peptides through biodegradable scaffolds. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Structural characterization and cell response evaluation of electrospun PCL membranes: Micrometric versus submicrometric fibers
Authors: Del Gaudio Costantino , Bianco Alessandra , Folin Marcella , Baiguera Silvia , Grigioni Mauro
Published: May 2008

Electrospinning is a valuable technique to fabricate fibrous scaffolds for tissue engineering. The typical nonwoven architecture allows cell adhesion and proliferation, and supports diffusion of nutrients and waste products. Poly(ε‐caprolactone) (PCL) electrospun membranes were produced starting from 14% w/v solutions in (a) mixture 1:1 tetrahydrofuran and N,N‐dimethylformamide and (b) chloroform. Matrices made up of randomly arranged uniform fibers free of beads were obtained. The average fiber diameters were (a) 0.8 ± 0.2 μm and (b) 3.6 ± 0.8 μm. PCL matrices showed the following tensile mechanical properties: tensile modulus (a) 5.0 ± 0.7 MPa (b) 6.4 ± 0.2 MPa, yield stress (a) 0.55 ± 0.06 MPa (b) 0.43 ± 0.02 MPa, and ultimate tensile stress (a) 1.7 ± 0.2 MPa and (b) 0.8 ± 0.1 MPa. The ultimate strain ranged between 300% and 400%. Cytotoxicity of electrospun membranes was continuously evaluated by means of electric cell–substrate impedance sensing technique using human umbilical vein endothelial cells (HUVEC). PCL matrices resulted free of toxic amounts of contaminants and/or process by‐products. In vitro studies performed by culturing HUVEC on micrometric and submicrometric fibrous mats showed that both structures supported cell adhesion and spreading. However, cells cultured on the micrometric network showed higher vitality and improved interaction with the polymeric fibers, suggesting an increased ability to promote cell colonization. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
In vivo study on hydroxyapatite scaffolds with trabecular architecture for bone repair
Authors: Appleford Mark R. , Oh Sunho , Oh Namsik , Ong Joo L.
Published: May 2008

The objective of this research was to investigate the bone formation and angio‐conductive potential of hydroxyapatite (HA) scaffolds closely matched to trabecular bone in a canine segmental defect after 3 and 12 weeks post implantation. Histomorphometric comparisons were made between naturally forming trabecular bone (control) and defects implanted with scaffolds fabricated with micro‐size (M‐HA) and nano‐size HA (N‐HA) ceramic surfaces. Scaffold architecture was similar to trabecular bone formed in control defects at 3 weeks. No significant differences were identified between the two HA scaffolds; however, significant bone in‐growth was observed by 12 weeks with 43.9 ± 4.1% and 50.4 ± 8.8% of the cross‐sectional area filled with mineralized bone in M‐HA and N‐HA scaffolds, respectively. Partially organized, lamellar collagen fibrils were identified by birefringence under cross‐polarized light at both 3 and 12 weeks post implantation. Substantial blood vessel infiltration was identified in the scaffolds and compared with the distribution and diameter of vessels in the surrounding cortical bone. Vessels were less numerous but significantly larger than native cortical Haversian and Volkmann canals reflecting the scaffold architecture where open spaces allowed interconnected channels of bone to form. This study demonstrated the potential of trabecular bone modeled, highly porous and interconnected, HA scaffolds for regenerative orthopedics. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Synthesis and evaluation of collagen–chitosan–hydroxyapatite nanocomposites for bone grafting
Authors: Wang Xiaoliang , Wang Xiaomin , Tan Yanfei , Zhang Bo , Gu Zhongwei , Li Xudong
Published: May 2008

Incorporation of hydroxyapatite (HA) into the matrix of collagen (Col) and chitosan (Chi) by in situ synthesis was introduced to prepare nanocomposites. Structural investigations of the pure Col–Chi mixture validated the influence of Chi on Col assembly, but the molecular interactions between Col and Chi was partially depressed during the intervention of in situ HA synthesis, as revealed by FTIR and DSC analyses. A series of Col–Chi–HA (CCHA) nanocomposites with varying HA content were thereby prepared by a sequential method, involving in situ synthesis in the Col–Chi system, then gelling at 25°C and subsequently washing the resultant elastic gel followed by dehydration consolidation. The structural characteristics and biological properties of the dehydrated CCHA nanocomposites were further evaluated by using XRD, FTIR, TG, and SEM analyses and the osteoblast culture experiment. Formation of a well integrated microstructure of organic fibers (ca. 90 nm in size) and dense matrix including inorganic aggregates (less than 30 nm in size) was found in these nanocomposites. Rat Ros 17/2.8 Osteoblasts proliferated and attached well on the surface of both CCHA nanocomposite and Col–Chi mixture. These results indicated that in situ HA synthesis in the Col–Chi system provided a feasible route for bone grafting nanocomposites. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Improvement in molecule exchange efficiency in Gibbs ensemble Monte Carlo: Development and implementation of the continuous fractional component move
Authors: Shi Wei , Maginn Edward J.
Published: May 2008

The continuous fractional component Monte Carlo (CFC MC) move (J Chem Theory Comput, 2007, 3, 1451) is extended to the Gibbs ensemble. The algorithm is validated against conventional simulations for the Lennard Jones fluid and a flexible water model. The method is also used to compute the vapor‐liquid coexistence densities of a model for SO2. The CFC molecule exchange move relies on the gradual insertion and deletion of molecules in conjunction with a self‐adapting bias potential. As a result, the method does not require the formation of spontaneous voids in the dense fluid phase to be successful, leading to molecule exchange acceptance probabilities that are nearly independent of temperature. For example, over 1% of the vapor‐liquid molecule exchange moves are successful for water at 280 K, whereas advanced rotational and configurational bias methods have success rates of less than 0.03%. The CFC move can be combined with other Monte Carlo moves to enable efficient simulation of dense strongly associating fluids that are to this point infeasible to model with standard methods. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008
Interactions between the L1 cell adhesion molecule and ezrin support traction‐force generation and can be regulated by tyrosine phosphorylation
Authors: Sakurai Takeshi , Gil Orlando D. , Whittard John D. , Gazdoiu Mihaela , Joseph Todd , Wu James , Waksman Adam , Benson Deanna L. , Salton Stephen R. , Felsenfeld Dan P.
Published: May 2008

An Ig superfamily cell‐adhesion molecule, L1, forms an adhesion complex at the cell membrane containing both signaling molecules and cytoskeletal proteins. This complex mediates the transduction of extracellular signals and generates actin‐mediated traction forces, both of which support axon outgrowth. The L1 cytoplasmic region binds ezrin, an adapter protein that interacts with the actin cytoskeleton. In this study, we analyzed L1–ezrin interactions in detail, assessed their role in generating traction forces by L1, and identified potential regulatory mechanisms controlling ezrin–L1 interactions. The FERM domain of ezrin binds to the juxtamembrane region of L1, demonstrated by yeast two‐hybrid interaction traps and protein binding analyses in vitro. A lysine‐to‐leucine substitution in this domain of L1 (K1147L) shows reduced binding to the ezrin FERM domain. Additionally, in ND7 cells, the K1147L mutation inhibits retrograde movement of L1 on the cell surface that has been linked to the generation of the traction forces necessary for axon growth. A membrane‐permeable peptide consisting of the juxtamembrane region of L1 that can disrupt endogenous L1–ezrin interactions inhibits neurite extension of cerebellar cells on L1 substrates. Moreover, the L1–ezrin interactions can be modulated by tyrosine phosphorylation of the L1 cytoplasmic region, namely, Y1151, possibly through Src‐family kinases. Replacement of this tyrosine together with Y1176 with either aspartate or phenylalanine changes ezrin binding and alters colocalization with ezrin in ND7 cells. Collectively, these data suggest that L1–ezrin interactions mediated by the L1 juxtamembrane region are involved in traction‐force generation and can be regulated by the phosphorylation of L1. © 2008 Wiley‐Liss, Inc.
Caveat emptor, caveat venditor: buyers and sellers beware the tender trap
Authors: Harris Ian , Mainelli Michael , Jones Haydn
Published: May 2008

Suppliers increasingly find themselves required to put in competitive tenders in order to win business, especially public sector contracts. Indeed, large organizations of all kinds, including NGOs, increasingly require their suppliers to go through structured tendering processes. But often those structured tendering processes are inappropriate for the procurement situation, leading to non‐optimal results for both buyers and sellers.

Copyright © 2008 John Wiley & Sons, Ltd.
Strategic knowledge management: creating comparative advantages
Authors: Kasper Helmut , Mühlbacher Jürgen , Müller Barbara
Published: May 2008

Knowledge management can be seen as an important precondition to build dynamic capabilities and comparative advantages (Teece et al., 1997). In this article we look at the interdependencies among knowledge management, the market segment chosen, and the strategy of multinational companies.

Based on the theoretical literature about dynamic capabilities and competition, we will build a model on the relationship of knowledge management and strategic management. We support the theoretical results with the findings of four cases involving multinational companies.

We differentiate among four settings of knowledge management and corporate strategy, depending on the dynamics of the market (external focus), the rate of innovation (internal focus), and the dominant kind of knowledge used in an industry.

Copyright © 2008 John Wiley & Sons, Ltd.