bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure–Activity Relationships of Melanocortin Agonists Containing the Benzimidazole Scaffold
Authors: Todorovic Aleksandar , Joseph Christine G. , Sorensen Nicholas B. , Wood Michael S. , Haskell‐Luevano Carrie
Published: May 2007

The melanocortin system has been implicated in regulating various physiological processes including pigmentation, energy homeostasis, obesity, steroidogenesis cardiovascular, and exocrine gland function. The five melanocortin receptors that belong to the super family of G protein‐coupled receptors are stimulated by naturally occurring agonists. The aim of this research was focused on the design, synthesis, and pharmacological characterization of melanocortin ligands that contain the 1,2,5‐trisubstituted benzimidazole scaffold. A series of benzimidazole analogues, with three points of diversity at positions 1, 2, and 5, were designed, synthesized, pharmacologically assayed at the mouse melanocortin receptors MC1R, MC3R, MC4R, and MC5R and resulted in ligands possessing a range of agonist activity from nm to no stimulation at up to 100 μM concentrations. This study demonstrates that the benzimidazole structure template can be appended with key melanocortin agonist amino acids for the design melanocortin receptor agonist ligands.
Witness preparation and the prosecution of rape
Authors: Ellison Louise
Published: May 2007

In England and Wales, rape complainants currently receive little by way of pre-trial support and preparation. This stands in sharp contrast to prosecutorial practice in the USA where prosecutors meet with complainants prior to trial with the specific aim of preparing them for the unfamiliar process of testifying in criminal proceedings. This paper considers the case for adopting similar arrangements in rape cases in England and Wales. This is assessed primarily from an evidentiary perspective although due consideration is also given to the need to protect vulnerable complainants from the risk of secondary victimisation within the criminal trial process.
Growth Response and Resistance to Streptococcus iniae of Nile Tilapia, Oreochromis niloticus, Fed Diets Containing Distiller’s Dried Grains with Solubles
Authors: Lim Chhorn , Garcia Julio C. , Yildirim‐Aksoy Mediha , Klesius Phillip H. , Shoemaker Craig A. , Evans Joyce J.
Published: May 2007

This study was conducted to evaluate the effect of dietary levels of distiller’s dried grains with solubles (DDGS) on growth, body composition, hematology, and resistance of Nile tilapia, Oreochromis niloticus, to Streptococcus iniae challenge. Five isocaloric diets containing DDGS at levels of 0, 10, 20, and 40%, and 40% DDGS + lysine (Diets 1–5) as partial replacements of a combination of soybean meal (SBM) and corn meal (CM) on an equal protein basis were fed to juvenile Nile tilapia (9.41 ± 0.14 g) for 10 wk. Fish fed Diet 4 had the lowest weight gain (WG), feed efficiency ratio, protein efficiency ratio (PER), and whole‐body protein. Supplementation of lysine to the 40% DDGS diet (Diet 5) improved WG and PER. Hematological and immunological parameters were not affected by dietary treatment. There were no significant differences among the average number of days to first mortality after S. iniae challenge and cumulative mortality 14 d postchallenge among fish in various treatments. DDGS can be incorporated in tilapia diet at a level of 20% as a substitute for a combination of SBM and CM without affecting their growth performance, body composition, hematological parameters, immune response, and resistance to S. iniae infection.
Dietary Supplementation of a Purified Nucleotide Mixture Transiently Enhanced Growth and Feed Utilization of Juvenile Red Drum, Sciaenops ocellatus
Authors: Li Peng , Gatlin Delbert M. , Neill William H.
Published: May 2007

Abstract.— Commercial nucleotide products have been shown to enhance early growth as well as immunity and disease resistance in aquacultured fish. Thus, we investigated effects of a purified nucleotide mixture on growth and health of young red drum. The nucleotide premix, containing salts of cytidine, uridine, adenosine, and guanidine, was coated with binders, freeze‐dried, and grounded to powder. A fish‐meal‐based diet was supplemented with 0.03, 0.1, or 0.3% by weight of the coated nucleotide mixture or with 0.2% Optimûn® (Chemoforma Co., Basel, Switzerland), a commercial nucleotide product. The experimental diets were maintained isonitrogenous and isocaloric by adjusting amounts of casein, gelatin, and alanine. Five replicate groups of 12 juvenile red drum (10.2 ± 0.2 g/fish, mean ± SD) were fed each experimental diet for 4 wk, followed by an assay of neutrophil oxidative radical production and a bacterial challenge via intraperitoneal injection of Vibrio harveyi at 2.9 × 107 colony‐forming units/g fish. Fish fed all diets supplemented with various levels of purified nucleotides showed significantly (P < 0.01) enhanced weight gain and feed efficiency during the first week of feeding compared to fish fed the basal diet. However, the dietary effects became less significant during the following 3 wk of feeding. The transient growth‐enhancing effect of dietary nucleotides observed in the present study may explain the conventional controversy about nucleotide effects on fish growth. Dietary supplementation with nucleotides had no influence on terminal whole‐body composition.
Physiological Responses of Nile Tilapia, Oreochromis niloticus, Fed Vitamin C‐ and Lipid‐Supplemented Diets and Submitted to Low‐Temperature Stress*
Authors: Falcon Dario R. , Barros Margarida M. , Pezzato Luiz E. , Sampaio Fernanda G. , Hisano Hamilton
Published: May 2007

Abstract.— Water temperature alterations can determine harmful physiological modifications in fish, which should be prepared to cope with this, and nutrition strategies seem to be essential. This study evaluated the effects of different levels of vitamin C and lipids on physiological responses of Nile tilapia, Oreochromis niloticus, submitted to temperature stress. There were two phases: Phase I – preparing fish to store vitamin C and lipid at appropriate temperature, and Phase II – evaluating the contributions these reserves make to fish physiology under low‐temperature stress. The experiment used a 3 × 2 factorial design with three vitamin C levels (300, 600, and 1200 mg/kg diet) and two lipid levels (8.0 and 12.0%), plus absence of nutrient test and a diet of 6.0% lipids and 125.0 mg/kg vitamin C. In Phase I, 192 fish were kept at 26.0 ± 1.0 C for 112 d, and in Phase II, 48 fish were kept at 18.0 ± 0.5 C for 32 d and at 15.0 ± 0.5 C for 11 d. Fish fed C0L0 diet showed lower erythrocytes values in both phases; higher vitamin C supplement determined higher red blood cell (RBC) number and higher hematocrit (Htc) (Phase II); Htc was significantly lower in Phase II; after temperature stress, fish fed C0L0 diet had higher mean corpuscular volume, lower hemoglobin corpuscular concentration, and significantly lower vitamin C concentration in the liver; and higher supplementation determined a higher concentration in the liver (Phases I and II). Higher plasmatic cortisol concentration was seen in fish fed C0L0 diet. In conclusion, our results show that the absence of vitamin C in diets impairs RBC formation and does not enable fish to cope with stress; excess vitamin C is efficient in mitigating stress and 600 mg/kg diet is economic and physiologically sufficient to prepare fish for coping with low‐temperature stress. Lipid supplementation does not determine alterations in stress biochemical parameters.
Fish Offal Recycling by the Black Soldier Fly Produces a Foodstuff High in Omega‐3 Fatty Acids
Authors: St‐Hilaire Sophie , Cranfill Katie , McGuire Mark A. , Mosley Erin E. , Tomberlin Jeffery K. , Newton Larry , Sealey Wendy , Sheppard Craig , Irving Stephen
Published: May 2007

Abstract.— The black soldier fly, Hermetia illucens, has the potential to reduce animal waste on livestock facilities and produce an animal‐grade feedstuff high in protein and fat. The lipid content of insects is largely dependent on their diet. Data from this study suggest that black soldier fly prepupae incorporate α‐linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) when fish offal is included in their diet. Fly larvae were fed three different proportions of fish offal and cow manure diets over a 21‐d trial. An additional group of larvae were fed 22% fish offal diet within 24 h of their pupation. Larvae fed fish offal were, on average, 30% lipid, which was 43% more than the controls fed cow manure only, and approximately 3% of this lipid was omega‐3 fatty acids (EPA, DHA, and ALA). Furthermore, this concentration of omega‐3 fatty acids was achieved within 24 h of feeding fish offal. These omega‐3 fatty‐acid‐enhanced prepupae may be a suitable fish meal and fish oil replacement for carnivorous fish and other animal diets. In addition, they may provide a method of reducing and recycling fish offal from processing plants.
Current and Future Trends of Climatic Extremes in Switzerland
Authors: Beniston Martin
Published: May 2007

This article provides an overview of extreme climatic events that are a feature of current and future climate that require full understanding if they are to be assessed in terms of social and economic costs. A review is made of the type of events that are important in mid‐latitudes, with examples taken from the heat waves, floods and wind‐storms that have affected Switzerland during the twentieth century. Regional climate model results are also presented for a scenario conducted over Europe. These simulations suggest that there may be significant shifts in the frequency and intensity of many forms of extremes as a warmer global climate progressively replaces current climate. In view of the potential losses in human, economic and environmental terms, extreme events and their future evolution need to carefully assessed in order to formulate appropriate adaptation strategies aimed at minimizing the negative impacts that extremes are capable of generating.
GeoTools: A Toolkit for Fluvial System Analysis1
Authors: Bledsoe Brian P. , Brown Michael C. , Raff David A.
Published: May 2007

Abstract:  Detailed mechanistic modeling of hydrogeomorphic processes in fluvial systems is extremely challenging, expensive, and of limited usefulness without explicit knowledge of prediction uncertainty. Accordingly, there is a need for parsimonious tools that support probabilistic scientific assessments of physical‐biological linkages in streams and rivers. This paper introduces GeoTools, a suite of analysis tools for fluvial systems written in Visual Basic for Applications/Excel. Based on flow time series and basic geomorphic data, GeoTools automates computation of numerous hydrologic, hydraulic, and geomorphic descriptors including effective discharge, sediment transport and yield, temporal distributions of hydraulic parameters (e.g., shear stress and specific stream power), cumulative erosion potential, channel stability indices, and over 100 flow regime metrics. GeoTools accepts input flow records in standard USGS format and a variety of other formats and temporal densities. The package also serves as a post‐processor for SWMM, and HSPF/BASINS model output. Three case studies illustrate specific applications of GeoTools: a channel restoration project, a stormwater management/hydromodification study, and an analysis of the effects of flow regulation below an impoundment dam.
Five Hundred Years of Hydrological Drought in the Upper Colorado River Basin1
Authors: Timilsena Janak , Piechota Thomas C. , Hidalgo Hugo , Tootle Glenn
Published: May 2007

Abstract:  This article evaluates drought scenarios of the Upper Colorado River basin (UCRB) considering multiple drought variables for the past 500 years and positions the current drought in terms of the magnitude and frequency. Drought characteristics were developed considering water‐year data of UCRB’s streamflow, and basin‐wide averages of the Palmer Hydrological Drought Index (PHDI) and the Palmer Z Index. Streamflow and drought indices were reconstructed for the last 500 years using a principal component regression model based on tree‐ring data. The reconstructed streamflow showed higher variability as compared with reconstructed PHDI and reconstructed Palmer Z Index. The magnitude and severity of all droughts were obtained for the last 500 years for historical and reconstructed drought variables and ranked accordingly. The frequency of the current drought was obtained by considering two different drought frequency statistical approaches and three different methods of determining the beginning and end of the drought period (annual, 5‐year moving, and ten year moving average). It was concluded that the current drought is the worst in the observed record period (1923‐2004), but 6th to 14th largest in terms of magnitude and 1st to 12th considering severity in the past 500 years. Similarly, the current drought has a return period ranging from 37 to 103 years based on how the drought period was determined. It was concluded that if the 10‐year moving average is used for defining the drought period, the current drought appears less severe in terms of magnitude and severity in the last 500 years compared with the results using 1‐ and 5‐year averages.
A CT-Based High-Order Finite Element Analysis of the Human Proximal Femur Compared to In-vitro Experiments
Authors: Yosibash Zohar , Padan Royi , Joskowicz Leo , Milgrom Charles
Published: May 2007

The prediction of patient-specific proximal femur mechanical response to various load conditions is of major clinical importance in orthopaedics. This paper presents a novel, empirically validated high-order finite element method (FEM) for simulating the bone response to loads. A model of the bone geometry was constructed from a quantitative computerized tomography (QCT) scan using smooth surfaces for both the cortical and trabecular regions. Inhomogeneous isotropic elastic properties were assigned to the finite element model using distinct continuous spatial fields for each region. The Young’s modulus was represented as a continuous function computed by a least mean squares method. p-FEMs were used to bound the simulation numerical error and to quantify the modeling assumptions. We validated the FE results with in-vitro experiments on a fresh-frozen femur loaded by a quasi-static force of up to 1500N at four different angles. We measured the vertical displacement and strains at various locations and investigated the sensitivity of the simulation. Good agreement was found for the displacements, and a fair agreement found in the measured strain in some of the locations. The presented study is a first step toward a reliable p-FEM simulation of human femurs based on QCT data for clinical computer aided decision making.
Numerical Assessment of Thermal Response Associated With In Vivo Skin Electroporation: The Importance of the Composite Skin model
Authors: Becker S. M. , Kuznetsov A. V.
Published: May 2007

Electroporation is an approach used to enhance transdermal transport of large molecules in which the skin is exposed to a series of electric pulses. The structure of the transport inhibiting outer layer, the stratum corneum, is temporarily destabilized due to the development of microscopic pores. Consequently agents that are ordinarily unable to pass into the skin are able to pass through this outer barrier. Of possible concern when exposing biological tissue to an electric field is thermal tissue damage associated with Joule heating. This paper shows the importance of using a composite model in calculating the electrical and thermal effects associated with skin electroporation. A three-dimensional transient finite-volume model of in vivo skin electroporation is developed to emphasize the importance of representing the skin’s composite layers and to illustrate the underlying relationships between the physical parameters of the composite makeup of the skin and resulting thermal damage potential.
Equivalence Between Short-Time Biphasic and Incompressible Elastic Material Responses
Authors: Ateshian Gerard A. , Ellis Benjamin J. , Weiss Jeffrey A.
Published: May 2007

Porous-permeable tissues have often been modeled using porous media theories such as the biphasic theory. This study examines the equivalence of the short-time biphasic and incompressible elastic responses for arbitrary deformations and constitutive relations from first principles. This equivalence is illustrated in problems of unconfined compression of a disk, and of articular contact under finite deformation, using two different constitutive relations for the solid matrix of cartilage, one of which accounts for the large disparity observed between the tensile and compressive moduli in this tissue. Demonstrating this equivalence under general conditions provides a rationale for using available finite element codes for incompressible elastic materials as a practical substitute for biphasic analyses, so long as only the short-time biphasic response is sought. In practice, an incompressible elastic analysis is representative of a biphasic analysis over the short-term response δt⪡Δ2∕∥C4∥∥K∥, where Δ is a characteristic dimension, C4 is the elasticity tensor, and K is the hydraulic permeability tensor of the solid matrix. Certain notes of caution are provided with regard to implementation issues, particularly when finite element formulations of incompressible elasticity employ an uncoupled strain energy function consisting of additive deviatoric and volumetric components.
Effects of Tension-Compression Nonlinearity on Solute Transport in Charged Hydrated Fibrous Tissues Under Dynamic Unconfined Compression
Authors: Huang Chun-Yuh , Gu Wei Yong
Published: May 2007

Cartilage is a charged hydrated fibrous tissue exhibiting a high degree of tension-compression nonlinearity (i.e., tissue anisotropy). The effect of tension-compression nonlinearity on solute transport has not been investigated in cartilaginous tissue under dynamic loading conditions. In this study, a new model was developed based on the mechano-electrochemical mixture model [Yao and Gu, 2007, J. Biomech. Model Mechanobiol., 6, pp. 63–72, Lai et al., 1991, J. Biomech. Eng., 113, pp. 245–258], and conewise linear elasticity model [Soltz and Ateshian, 2000, J. Biomech. Eng., 122, pp. 576–586;Curnier et al., 1995, J. Elasticity, 37, pp. 1–38]. The solute desorption in cartilage under unconfined dynamic compression was investigated numerically using this new model. Analyses and results demonstrated that a high degree of tissue tension-compression nonlinearity could enhance the transport of large solutes considerably in the cartilage sample under dynamic unconfined compression, whereas it had little effect on the transport of small solutes (at 5% dynamic strain level). The loading-induced convection is an important mechanism for enhancing the transport of large solutes in the cartilage sample with tension-compression nonlinearity. The dynamic compression also promoted diffusion of large solutes in both tissues with and without tension-compression nonlinearity. These findings provide a new insight into the mechanisms of solute transport in hydrated, fibrous soft tissues.
Determination of Strain Gradient Plasticity Length Scale for
Microelectronics Solder Alloys
Authors: Gomez Juan , Basaran Cemal
Published: May 2007

Strain gradient plasticity theories that have emerged during recent years to provide an explanation for size dependent behavior exhibited by some materials have also created a need for additional material parameters. In this study on Pb∕Sn solder alloys’ material length scale, which is needed for use in strain gradient plasticity type constitutive models, is determined. The value of length scale is in agreement with values available in literature for different materials like copper, nickel, and aluminum.
Cross-Verification of Thermal Characterization of a
Microcooler
Authors: Kohári Zs. , Bognár Gy. , Horváth Gy. , Poppe A. , Rencz M. , Székely V.
Published: May 2007

The thermal behavior of a microcooler has been investigated using two different measurement methods to verify their feasibility. On the one hand structure function derived from the thermal measurements was used, while on the other hand, characterization was done with a heat-flux sensor array. The measurement sample was a square nickel plate microcooler holding 128 microchannels in radial arrangement. In our previous studies it was attached to a power transistor which was used as a dissipator and a temperature sensor. The thermal transient response to a dissipation step of the transistor was recorded in the measurement. The measured transients (cooling curves) were transformed into structure functions from which the partial thermal resistance corresponding to the cooling assembly was identified. In the current study the measurement setup was completed by a heat-flux sensor inbetween the dissipator and the microcooler to be able to verify the results extracted via structure functions. In this way we could compare the heat-transfer coefficient (HTC) values obtained from the identified thermal resistances to those calculated directly from the measured heat-flux values. Good matching of the HTC values resulting from the two different methods was found.
Pressure Drop of Impingement Air Cooled Plate Fin Heat Sinks
Authors: Duan Zhipeng , Muzychka Y. S.
Published: May 2007

The performance of impingement air cooled plate fin heat sinks differs significantly from that of parallel flow plate fin heat sinks. A simple impingement flow pressure drop model based on developing laminar flow in rectangular channels is proposed. The model is developed from simple momentum balance and utilizes fundamental solutions from fluid dynamics to predict its constitutive components. To test the validity of the model, experimental measurements of pressure drop are performed with heat sinks of various impingement inlet widths, fin spacings, fin heights, and airflow velocities. The accuracy of the pressure drop model was found to be within 20% of the experimental data taken on four heat sinks and other experimental data from the published literature at channel Reynolds numbers less than 1200. The simple model is suitable for impingement air cooled plate fin heat sinks parametric design studies.
Air Cooling of Variable Array of Heated Modules in a Vertical
Channel
Authors: Yadav Vipin , Kant Keshav
Published: May 2007

The effect of array size and substrate thermal conditions upon heat transfer characteristics of an array of heated modules subjected to buoyancy assisted convection cooling in air is investigated. The comparative analysis of numerical and experimental data for multimodular array of heated modules mounted on a printed circuit board (PCB) forming one of the walls of a vertical channel is presented. Numerical investigation involved turbulent flow analysis based on a realizable k−ε model. Experimental efforts involved development of a test rig and use of state-of-the-art data acquisition system for simulating the heat transfer phenomenon from the module surfaces under various test conditions. Moderate to high flow velocities in the channel and the heat flux values near those occurring in electronic cooling applications using air as coolant are considered. Initially, the data for mean Nusselt number occurring at various rows in the array under consideration are presented, and in order to validate the numerical model, variation pattern and deviation between numerical and experimental results are analyzed keeping the substrate (PCB) as the insulated surface. The same numerical model was extended to study the cases of varying substrate thermal conditions. An empirical relation is proposed for evaluating Nu under different substrate thermal conditions for array geometries considered and flow rates within the parametric ranges discussed.
A New Methodology to Determine the Anatomical Center and Radius of Curved Joint Surfaces
Authors: Meyer Dominik C. , Espinosa Norman , Lang Urs , Koch Peter P.
Published: May 2007

This study describes a mechanical tool which allows us to determine the radius and center of curved joint surfaces both intraoperatively and in vitro. The tool is composed of longitudinal parallel hinges, connected with cross bars on one end. In the middle of each cross bar, one needle is attached at an angle of 90deg to both the hinges and the cross bars. When the parallel hinges are held against a curved surface, they will adapt to the curvature and the needles on the cross bars will cross each other. The crossing point of two needles represents the mean center of the curvature within the plane spanned by the needles. The radius is the distance between the center of curvature and the joint surface. The proposed tool and method allow us to determine the mean center of convex or concave curvatures, which often represent the isometric point of a corresponding curved joint surface. Knowing the radius and center of curvature may facilitate various surgical procedures such as collateral or cruciate ligament reconstruction. Appropriate adaptations of the tool appear to be a useful basis for biomechanical and anatomical joint analyses in the laboratory.
Gravity-Balanced Arm Support With Energy-Free Adjustment
Authors: van Dorsser Wouter D. , Barents Rogier , Wisse Boudewijn M. , Herder Just L.
Published: May 2007

People with neuromuscular diseases have very limited muscle force. Many of them rely on mobile arm supports to move their arms. Most of these supports incorporate gravity balancers, i.e., spring-loaded mechanisms that achieve a constant total potential energy, thus eliminating any preferred position. The springs and the mechanism topology and dimensions are designed to exactly or approximately balance the weight of the user’s arm. Quasistatically, the mechanism, once statically balanced, can thus be moved virtually without operating energy. In case of change of effective arm weight, e.g., due to picking up an object or putting on a coat, the support mechanism should ideally be readjusted. In all available support mechanisms, this adjustment is associated with considerable mechanical effort, while clearly this application would benefit greatly from an energy-free adjustment. This paper will present an arm support that includes a novel design concept to adjust spring-based static balancers with no need for external energy. This concept will be explained, and several variants will be shown. Subsequently, the application of this concept in a mobile arm support will be described in detail, including preliminary clinical trial results.
RAP80 Targets BRCA1 to Specific Ubiquitin Structures at DNA Damage Sites
Authors: Sobhian Bijan , Shao Genze , Lilli Dana R. , Culhane Aedín C. , Moreau Lisa A. , Xia Bing , Livingston David M. , Greenberg Roger A.
Published: May 2007

Mutations affecting the BRCT domains of the breast cancer–associated tumor suppressor BRCA1 disrupt the recruitment of this protein to DNA double-strand breaks (DSBs). The molecular structures at DSBs recognized by BRCA1 are presently unknown. We report the interaction of the BRCA1 BRCT domain with RAP80, a ubiquitin-binding protein. RAP80 targets a complex containing the BRCA1-BARD1 (BRCA1-associated ring domain protein 1) E3 ligase and the deubiquitinating enzyme (DUB) BRCC36 to MDC1-γH2AX–dependent lysine
6
- and lysine
63
-linked ubiquitin polymers at DSBs. These events are required for cell cycle checkpoint and repair responses to ionizing radiation, implicating ubiquitin chain recognition and turnover in the BRCA1-mediated repair of DSBs.
Myosin V Walks by Lever Action and Brownian Motion
Authors: Shiroguchi Katsuyuki , Kinosita Kazuhiko
Published: May 2007

Myosin V is a molecular motor that moves cargo along actin filaments. Its two heads, each attached to a long and relatively stiff neck, move alternately forward in a “hand-over-hand” fashion. To observe under a microscope how the necks move, we attached a micrometer-sized rod to one of the necks. The leading neck swings unidirectionally forward, whereas the trailing neck, once lifted, undergoes extensive Brownian rotation in all directions before landing on a site ahead of the leading head. The neck-neck joint is essentially free, and the neck motion supports a mechanism where the active swing of the leading neck biases the random motion of the lifted head to let it eventually land on a forward site.
A Manganese(IV)/Iron(III) Cofactor in
Chlamydia trachomatis
Ribonucleotide Reductase
Authors: Jiang Wei , Yun Danny , Saleh Lana , Barr Eric W. , Xing Gang , Hoffart Lee M. , Maslak Monique-Anne , Krebs Carsten , Bollinger J. Martin
Published: May 2007

In a conventional class I ribonucleotide reductase (RNR), a diiron(II/II) cofactor in the R2 subunit reacts with oxygen to produce a diiron(III/IV) intermediate, which generates a stable tyrosyl radical (Y⚫). The Y⚫ reversibly oxidizes a cysteine residue in the R1 subunit to a cysteinyl radical (C⚫), which abstracts the 3′-hydrogen of the substrate to initiate its reduction. The RNR from
Chlamydia trachomatis
lacks the Y⚫, and it had been proposed that the diiron(III/IV) complex in R2 directly generates the C⚫ in R1. By enzyme activity measurements and spectroscopic methods, we show that this RNR actually uses a previously unknown stable manganese(IV)/iron(III) cofactor for radical initiation.
Ecological Genomics of Marine Roseobacters
Authors: Moran M. A. , Belas R. , Schell M. A. , González J. M. , Sun F. , Sun S. , Binder B. J. , Edmonds J. , Ye W. , Orcutt B. , Howard E. C. , Meile C. , Palefsky W. , Goesmann A. , Ren Q. , Paulsen I. , Ulrich L. E. , Thompson L. S. , Saunders E. , Buchan A.
Published: May 2007

Bacterioplankton of the marine
Roseobacter
clade have genomes that reflect a dynamic environment and diverse interactions with marine plankton. Comparative genome sequence analysis of three cultured representatives suggests that cellular requirements for nitrogen are largely provided by regenerated ammonium and organic compounds (polyamines, allophanate, and urea), while typical sources of carbon include amino acids, glyoxylate, and aromatic metabolites. An unexpectedly large number of genes are predicted to encode proteins involved in the production, degradation, and efflux of toxins and metabolites. A mechanism likely involved in cell-to-cell DNA or protein transfer was also discovered:
vir
-related genes encoding a type IV secretion system typical of bacterial pathogens. These suggest a potential for interacting with neighboring cells and impacting the routing of organic matter into the microbial loop. Genes shared among the three roseobacters and also common in nine draft
Roseobacter
genomes include those for carbon monoxide oxidation, dimethylsulfoniopropionate demethylation, and aromatic compound degradation. Genes shared with other cultured marine bacteria include those for utilizing sodium gradients, transport and metabolism of sulfate, and osmoregulation.
Physicians’ intent to comply with the American Medical Association’s guidelines on gifts from the pharmaceutical industry
Authors: Pinto Sharrel L , Lipowski Earlene , Segal Richard , Kimberlin Carole , Algina James
Published: May 2007

Objective:To identify factors that predict physicians’ intent to comply with the American Medical Association’s (AMA’s) ethical guidelines on gifts from the pharmaceutical industry.

Methods:A survey was designed and mailed in June 2004 to a random sample of 850 physicians in Florida, USA, excluding physicians with inactive licences, incomplete addresses, addresses in other states and pretest participants. Factor analysis extracted six factors: attitude towards following the guidelines, subjective norms (eg, peers, patients, etc), facilitating conditions (eg, knowledge of the guidelines, etc), profession-specific precedents (eg, institution’s policies, etc), individual-specific precedents (physicians’ own discretion, policies, etc) and intent. Multivariate regression modelling was conducted.

Results:Surveys were received from 213 physicians representing all specialties, with a net response rate of 25.5%. 62% (n = 133) of respondents were aware of the guidelines; 50% (n = 107) had read them. 48% (n = 102) thought that following the guidelines would increase physicians’ credibility and professional image; 68% (n = 145) agreed that it was important to do so. Intent to comply was positively associated with attitude, subjective norms, facilitators and sponsorship of continuing medical education (CME) events, while individual-specific precedents had a negative relationship with intent to comply. Predictors of intent (R2 = 0.52, p <0) were attitude, subjective norms, the interaction term (attitude and subjective norms), sponsorship of CME events and individual-specific precedents.

Conclusions:Physicians are more likely to follow the AMA guidelines if they have positive attitudes towards the guidelines, greater subjective norms, fewer expectations of CME sponsorship and fewer individual-specific precedents. Physicians believing that important individuals or organisations expect them to comply with the guidelines are more likely to express intent, despite having fewer beliefs that positive outcomes would result through compliance.
Ethical dilemmas in forensic psychiatry: two illustrative cases
Authors: Sen Piyal , Gordon Harvey , Adshead Gwen , Irons Ashley
Published: May 2007

One approach to the analysis of ethical dilemmas in medical practice uses the “four principles plus scope” approach. These principles are: respect for autonomy, beneficence, non-maleficence and justice, along with concern for their scope of application. However, conflicts between the different principles are commonplace in psychiatric practice, especially in forensic psychiatry, where duties to patients often conflict with duties to third parties such as the public. This article seeks to highlight some of the specific ethical dilemmas encountered in forensic psychiatry: the excessive use of segregation for the protection of others, the ethics of using mechanical restraint when clinically beneficial and the use of physical treatment without consent. We argue that justice, as a principle, should be paramount in forensic psychiatry, and that there is a need for a more specific code of ethics to cover specialised areas of medicine like forensic psychiatry. This code should specify that in cases of conflict between different principles, justice should gain precedence over the other principles.
Is respect for autonomy defensible?
Authors: Wilson James
Published: May 2007

Three main claims are made in this paper. First, it is argued that Onora O’Neill has uncovered a serious problem in the way medical ethicists have thought about both respect for autonomy and informed consent. Medical ethicists have tended to think that autonomous choices are intrinsically worthy of respect, and that informed consent procedures are the best way to respect the autonomous choices of individuals. However, O’Neill convincingly argues that we should abandon both these thoughts. Second, it is argued that O’Neill’s proposed solution to this problem is inadequate. O’Neill’s approach requires that a more modest view of the purpose of informed consent procedures be adopted. In her view, the purpose of informed consent procedures is simply to avoid deception and coercion, and the ethical justification for informed consent derives from a different ethical principle, which she calls principled autonomy. It is argued that contrary to what O’Neill claims, the wrongness of coercion cannot be derived from principled autonomy, and so its credentials as a justification for informed consent procedures is weak. Third, it is argued that we do better to rethink autonomy and informed consent in terms of respecting persons as ends in themselves, and a characteristically liberal commitment to allowing individuals to make certain categories of decisions for themselves.
Leukaemia, brain tumours and exposure to extremely low frequency magnetic fields: cohort study of Swiss railway employees
Authors: Röösli Martin , Lörtscher Manfred , Egger Matthias , Pfluger Dominik , Schreier Nadja , Lörtscher Emanuel , Locher Peter , Spoerri Adrian , Minder Christoph
Published: May 2007

Aims:To investigate the relationship between extremely low frequency magnetic field (ELF-MF) exposure and mortality from leukaemia and brain tumour in a cohort of Swiss railway workers.

Methods:20 141 Swiss railway employees with 464 129 person-years of follow-up between 1972 and 2002 were studied. Mortality rates for leukaemia and brain tumour of highly exposed train drivers (21 μT average annual exposure) were compared with medium and low exposed occupational groups (i.e. station masters with an average exposure of 1 μT). In addition, individual cumulative exposure was calculated from on-site measurements and modelling of past exposures.

Results:The hazard ratio (HR) for leukaemia mortality of train drivers was 1.43 (95% CI 0.74 to 2.77) compared with station masters. For myeloid leukaemia the HR of train drivers was 4.74 (95% CI 1.04 to 21.60) and for Hodgkin’s disease 3.29 (95% CI 0.69 to 15.63). Lymphoid leukaemia, non-Hodgkin’s disease and brain tumour mortality were not associated with magnetic field exposure. Concordant results were obtained from analyses based on individual cumulative exposure.

Conclusions:Some evidence of an exposure–response association was found for myeloid leukaemia and Hodgkin’s disease, but not for other haematopoietic and lymphatic malignancies and brain tumours.
Carnivore-specific stable isotope variables and variation in the foraging ecology of modern and ancient wolf populations: case studies from Isle Royale, Minnesota, and La Brea
Authors: Fox-Dobbs K. , Bump J.K. , Peterson R.O. , Fox D.L. , Koch P.L.
Published: May 2007

We use carbon and nitrogen isotope data collected from two North American gray wolf ( Canis lupus L., 1758) populations (Isle Royale and northern Minnesota) to both calculate carnivore-specific isotopic variables and investigate wolf foraging ecology. The isotopic enrichments of13C and15N that occur between mammalian carnivores and their prey have not been well defined in modern populations. We use bone collagen from the Isle Royale National Park wolf, moose ( Alces alces (L., 1758)), and beaver ( Castor canadensis Kuhl, 1820) populations to determine trophic enrichment factors of 1.3‰ ± 0.6‰ for δ13C and 4.6‰ ± 0.7‰ for δ15N. We apply these carnivore-specific fractionation factors to a case study from the fossil record, and reconstruct the diets of late-Pleistocene dire wolves ( Canis dirus (Leidy, 1858)) from the La Brea tar pits. We use the Minnesota wolf tissue (collagen, hair, muscle) isotopic data to estimate carnivore population subsample sizes needed to replicate the mean values of the whole population within one standard deviation. Finally, we compare the Isle Royale and Minnesota collagen and hair isotopic data to published δ13C and δ15N values for North American gray wolf populations. We find that interpopulation differences in isotope variances provide insight into wolf foraging ecology.
Effect of forest use on trophic levels of small mammals: an analysis using stable isotopes
Authors: Nakagawa Michiko , Hyodo Fujio , Nakashizuka Tohru
Published: May 2007

The degradation of tropical forests is progressing rapidly and its ecological effects on wild animals are a global concern. We evaluated the hypothesis that small mammals in highly degraded forest occupy higher trophic levels than those in somewhat degraded forests, as indicated by diets high in consumers such as insects, in a tropical rain forest in Sarawak, Malaysia. After correcting for differences in the δ15N values for primary production among the study sites, the δ15Ncorrected values for rats and mice (Muridae) differed significantly among forest types. Rats and mice in more degraded forest had higher δ15Ncorrected values than those in less degraded or primary forest; in contrast, treeshrews (Tupaiidae) and squirrels (Sciuridae) showed no significant differences in the δ15Ncorrected values among forest types. We found significant positive correlations between canopy openness and the δ15Ncorrected values for one species of squirrel and two species of rats. This hypothesis was supported for small mammals that have normal dietary preferences for plants, i.e., omnivorous rodents, but not for those that normally prefer insects, i.e., treeshrews. The δ15N values for omnivorous mammals may be useful as an indicator of changes in food-web structure in response to forest disturbance.
Unusual fatty acid biomarkers reveal age- and sex-specific foraging in polar bears (Ursus maritimus)
Authors: Thiemann G.W. , Budge S.M. , Iverson S.J. , Stirling I.
Published: May 2007

We used fatty acid (FA) biomarkers in a novel approach to study the foraging habits of a top predator. We tested the hypothesis that non-methylene-interrupted FA (NMI FA), synthesized by benthic molluscs, are transferred via pinnipeds to polar bears ( Ursus maritimus Phipps, 1774) at the top of the arctic marine food web. Among eight species of marine mammals preyed upon by polar bears, NMI FA were prevalent only in benthic-feeding bearded seals ( Erignathus barbatus (Erxleben, 1777)) and Atlantic walruses ( Odobenus rosmarus rosmarus (L., 1758)). These two prey species differed in their relative proportions of NMI FA — 22:2Δ7,15 was almost exclusive to bearded seals, whereas 20:2Δ5,11 was most abundant in Atlantic walruses. Six different NMI FA were identified in polar bears. Trends in individual NMI FA showed that large, adult male polar bears were the primary predators of bearded seals and Atlantic walruses. These findings were confirmed through quantitative FA signature analysis (QFASA) using an entirely different set of FA. In addition to corroborating the accuracy of QFASA diet estimates, these results indicate that individual NMI FA can provide specific information on polar bear foraging and therefore provide insights into the bottom–up effects of environmental change in arctic ecosystems.
Resource tracking by eastern chipmunks: the sampling of renewing patches
Authors: Hall C.L. , Humphries M.M. , Kramer D.L.
Published: May 2007

When food patches vary in quality over time, sampling by repeated visits can allow animals to track this variation and improve their foraging success. Sampling, however, requires spending time visiting patches that are currently poor. The optimal investment in sampling should depend on characteristics of the patch, the animal, and the environment, but there are few empirical studies of these relationships in nature. Here, we describe discovery, exploitation, and sampling of randomly varying artificial food patches by free-ranging eastern chipmunks ( Tamias striatus (L., 1758)). Chipmunks effectively tracked variation over a broad time scale, discovering patches within a few days, sampling and exploiting over several weeks, and decreasing sampling when renewals ceased. Sampling allowed the chipmunks to track variation on an hourly scale through rapid discovery of renewals. Sampling rates were high (median = 0.3 visits·individual–1·h–1; range = 0–4.2). Sampling was not affected by the frequency or magnitude of patch renewal but was lower for chipmunks whose burrows were farther from the patch. Sampling is an important part of chipmunk foraging strategy, but the difficulty of estimating patch quality and renewal rate and the effects of competition may prevent a close matching between sampling rate and patch characteristics under natural conditions.
Optimal descent angles for shallow-diving cormorants
Authors: Ribak G. , Strod T. , Weihs D. , Arad Z.
Published: May 2007

Air-breathing divers should attempt to maximize foraging efficiency under the constraint of limited oxygen availability. For diving water birds, high buoyancy (owing to the air in the plumage) and the associated change in buoyancy with diving depth impose further constraints on the adaptation to aquatic life. Diving birds are expected to descend as fast as possible to escape the higher buoyancy near the water surface, but in practice, shallow-diving cormorants (genus Phalacrocorax Brisson, 1760) are often observed descending the water column in relatively small angles with respect to the water surface. We derive a theoretical biomechanical model for the energetics of the descent phase of a dive of foot-propelled cormorants feeding on benthic prey at shallow depth. The model shows that visually guided benthic feeders benefit energetically from diving at small descent angles when optical conditions and bottom depth allow. The model also explains the high variation in descent angles observed in free-ranging birds, as well as the observed correlation between descent angle and bottom depth in cormorants.
PHENOMENA IN RESONANT TUNNELING THROUGH DEGENERATED ENERGY STATES WITH ELECTRON CORRELATION
Authors: ERMAKOV VLADIMIR N. , KRUCHININ SERGEI P. , HORI HIDENOBU , FUJIWARA AKIHIKO
Published: May 2007

We introduce a general analysis method, which allows us to simulate the operation of high-performance molecular nano-devices and to design the expected function of a wide range of devices in nano-scale size. The method is based on the use of a resonant tunneling phenomenon, admitting strong electron correlation in a quantum dot with degenerated states. Three examples of the application of this method are given: Coulomb repulsion, uncorrelated resonant tunneling, and electron-phonon interaction. It is shown that there is a good agreement with experimental data in all three cases.
NONLINEAR TE SURFACE WAVES IN A PHOTOSENSITIVE SEMICONDUCTOR FILM BOUNDED BY A SUPERCONDUCTOR COVER
Authors: HAMADA M. S. , EL-ASTAL A. H. , SHABAT M. M.
Published: May 2007

A theoretical investigation of TE nonlinear surface waves propagating in a photosensitive semiconductor-superconductor layers structure is fully described. The dispersion relation has been found and the effect of nonlinearity, operating angular frequency and the effect of temperature of the superconductor on the propagation characteristics have been examined. The power flow has also been studied. It has been shown that temperature and frequency increase the losses.
Solid Oxide Fuel Cell Development at Topsoe Fuel Cell A/S and Riso̸ National Laboratory
Authors: Christiansen Niels , Hansen J B. , Larsen H H. , Linderoth S , Larsen Peter H. , Hendriksen Peter V. , Hagen Anke
Published: May 2007

The consortium of Topsoe Fuel Cell A/S and Riso̸ National Laboratory has up-scaled its production capacity. Stacks are based on a compact thin plate multilayer design with metallic interconnects and 12x12 cm2 or 18x18 cm2 foot print. Larger (500 cm2) cells are currently under evaluation. Stacks have been tested successfully for more than 13000 hours. Several 50 or 75 cell stacks in the 1+ kW power range have been tested successfully at a fuel utilisation of up to 92%. Multi stack modules consisting of four 75 cell stacks have been tested for more than 4000 hours with pre-reformed natural gas and modules consisting of twelve stacks are under development. Our SOFC program comprises development of next generation cells with porous ferritic steel is used as a cheap, ductile, robust cell support and the electrolyte is based on scandia- doped zirconia with improved durability. In collaboration with Wärtsilä, a 24-stack prototype based on natural gas is being tested. The range of fuels have further been extended to include ethanol and coal syn-gas by development of a new coke resistant catalyst suitable for future SOFC technology.
Solid Oxide Fuel Cell Development: Latest Results
Authors: Mukerjee Subhasish , Haltiner Karl , Kerr Rick , Chick Larry , Sprenkle Vince , Meinhardt Kerry , Lu Chun , Kim Jin Y. , Weil K. Scott
Published: May 2007

Delphi is developing Solid Oxide Fuel Cell (SOFC) technology for applications in a variety of markets (1-5). This paper outlines the development of SOFC stack by the Delphi Battelle team under the US Department of Energy's Solid State Energy Conversion Alliance (SECA) program. Delphi successfully completed Phase 1 of this program and met the key technical and cost targets. This paper outlines key achievements in stack development by the Delphi Battelle team in moving forward towards meeting the goals for commercialization.