bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of 884 MHz GSM wireless communication signals on headache and other symptoms: An experimental provocation study
Authors: Hillert Lena , Åkerstedt Torbjörn , Lowden Arne , Wiholm Clairy , Kuster Niels , Ebert Sven , Boutry Clementine , Moffat Scott Douglas , Berg Mats , Arnetz Bengt Birger
Published: November 2007

Findings from prior studies of possible health and physiological effects from mobile phone use have been inconsistent. Exposure periods in provocation studies have been rather short and personal characteristics of the participants poorly defined. We studied the effect of radiofrequency field (RF) on self‐reported symptoms and detection of fields after a prolonged exposure time and with a well defined study group including subjects reporting symptoms attributed to mobile phone use. The design was a double blind, cross‐over provocation study testing a 3‐h long GSM handset exposure versus sham. The study group was 71 subjects age 18–45, including 38 subjects reporting headache or vertigo in relation to mobile phone use (symptom group) and 33 non‐symptomatic subjects. Symptoms were scored on a 7‐point Likert scale before, after 1½ and 2¾ h of exposure. Subjects reported their belief of actual exposure status. The results showed that headache was more commonly reported after RF exposure than sham, mainly due to an increase in the non‐symptom group. Neither group could detect RF exposure better than by chance. A belief that the RF exposure had been active was associated with skin symptoms. The higher prevalence of headache in the non‐symptom group towards the end of RF exposure justifies further investigation of possible physiological correlates. The current study indicates a need to better characterize study participants in mobile phone exposure studies and differences between symptom and non‐symptom groups. Bioelectromagnetics 29:185–196, 2008. © 2007 Wiley‐Liss, Inc.
A developmental approach to violence, hostile attributions, and paranoid thinking in adolescence
Authors: Bailey Susan , Whittle Nathan , Farnworth Paulette , Smedley Kirsty
Published: November 2007

Research within the area of paranoid thinking has focused primarily on adults and has only recently looked at the effects during the critical life stage of adolescence, with even less research in the context of the juvenile justice system. This article aims to explore the relationship between antisocial behaviour in adolescence and the development of paranoid thinking, set within wider contexts that surround the juvenile justice system. The information presented is drawn from both the current research and the clinical experiences of those working in adolescent forensic psychiatry services. The relationships with other disorders such as conduct disorder, ADHD, PTSD, and depression are also explored. Copyright © 2007 John Wiley & Sons, Ltd.
Patent foramen ovale and unexplained ischemic cerebrovascular events in children
Authors: Benedik Mirjana Perkovič , Zaletel Marjan , Meglič Nuška Pečarič , Podnar Tomaž
Published: November 2007

Objectives:

To consider the role of patent foramen ovale (PFO) in ischemic cerebrovascular event of unknown cause in children.

Background:

Data regarding the possibility of paradoxical embolism in unexplained ischemic cerebrovascular event in children are lacking.

Methods:

Between January 2005 and March 2007, all consecutive children evaluated due to ischemic cerebrovascular event were included in the retrospective study. In addition to the standard diagnostic protocol, a contrast transcranial Doppler (TCD) with Valsalva maneuver (VM) was performed in patients with unexplained events. Percutaneous PFO closure was offered to all patients with ischemic cerebrovascular event of unknown cause and presumed paradoxical embolism.

Results:

Eighteen patients aged between 2 and 17 years (median 11.5 years) were included in the study: 12 patients suffered ischemic stroke and six with transient ischemic attack (TIA). In six patients, ischemic stroke was of unknown cause and contrast TCD with VM was positive in four of them. In addition, TCD study was positive in five patients evaluated because of TIA. Nine patients with presumed paradoxical embolism underwent an attempt at the percutaneous PFO closure.

Conclusions:

It appears that the role of PFO in ischemic cerebrovascular event of unknown cause in children may be underestimated. Contrast TCD with VM is a sensitive, noninvasive method for PFO detection, proved in our experience particularly suitable for children. In children with unexplained ischemic cerebrovascular event and presumed paradoxical embolism, percutaneous PFO closure should be considered. © 2007 Wiley‐Liss, Inc.
Coaxial double catheter technique followed by buddy wire placement for ostial lesion of right coronary artery with anterior take‐off
Authors: Furuichi Shinichi , Sangiorgi Giuseppe M. , Colombo Antonio
Published: November 2007

This report describes a technique for percutaneous coronary intervention in an ostial lesion with difficult take‐off utilising an 8F guiding catheter and a 5F 125 cm‐long diagnostic catheter followed by buddy wire placement. © 2007 Wiley‐Liss, Inc.
Spider‐Like Oligothiophenes
Authors: Benincori Tiziana , Capaccio Marcello , De Angelis Filippo , Falciola Luigi , Muccini Michele , Mussini Patrizia , Ponti Alessandro , Toffanin Stefano , Traldi Pietro , Sannicolò Francesco
Published: November 2007

Careful analysis and comparison of optical and electrochemical data available in recent literature for multi‐thiophene molecular assemblies suggested a few basic rules for the design of structurally simple and easily accessible oligothiophenes endowed with properties not far from those exhibited by much more complex and synthetically demanding architectures. The synthesis and computational investigation of three examples of a class of oligothiophenes (spider‐like) tailored according to these indications are reported together with their exhaustive optical and electrochemical characterization. The new compounds (T95, T146, T197) are characterized by a thiophene, a 2,2′‐bithiophene and a 2,2′,5′,2′′‐terthiophene unit (the spider body) fully substituted with 5‐(2,2′‐bithiophen)yl pendants (the spider legs). Absorption and electrochemical data are in good agreement and point to a high π‐conjugation level, comparable to those displayed by much larger assemblies. Electrode potential cycling in proximity of the first oxidation peak affords fast and reproducible formation of conducting, highly stable [TXn]m films, mainly consisting of dimers (m=2). Electrooxidation kinetic experiments on deuterium‐labelled T95, coupled to laser‐desorption‐ionization mass spectroscopy on the resulting dimer demonstrated that the coupling process is extremely regioselective in the α positions of the more conjugated pentathiophene chain. The optical and the electrochemical properties of the films are reported and discussed. A peculiar feature is their impressive charge‐trapping ability. Spider‐like oligothiophenes are promising materials for applications as active layers in multifunctional organic devices.
Ultrasensitive Fluorescent Responses of Water‐Soluble, Zwitterionic, Boronic Acid‐Bearing, Regioregular Head‐to‐Tail Polythiophene to Biological Species
Authors: Xue Cuihua , Cai Feifei , Liu Haiying
Published: November 2007

Water‐soluble regioregular head‐to‐tail zwitterionic fluorescent conjugated boronic acid‐bearing polythiophene (polymer 2) was prepared through a postpolymerization quaternization of a pyridine group of 3‐pyridineboronic acid with bromide groups of regioregular head‐to‐tail poly(3‐bromohexylthiophene) (polymer 1). Titration of monosaccharides, lactose, ascorbic acid, or dopamine with 0.1 M phosphate buffer (pH 7.4), containing 4.0 μM of polymer 2, results in significant concentration‐dependent quenching of the polymer fluorescence. The polymer displays an optimum response to the biological species at pH 7.0. The binding constants of polymer 2 with mannose, fructose, glucose, galactose, vitamin C, dopamine, and lactose are 3.33×104, 1.13×105, 1.23×105, 1.69×105, 3.17×105, 3.27×105, and 4.60×105, respectively.
Nitric oxide regulates axonal regeneration in an insect embryonic CNS
Authors: Stern Michael , Bicker Gerd
Published: November 2007

In higher vertebrates, the central nervous system (CNS) is unable to regenerate after injury, at least partially because of growth‐inhibiting factors. Invertebrates lack many of these negative regulators, allowing us to study the positive factors in isolation. One possible molecular player in neuronal regeneration is the nitric oxide (NO)—cyclic guanosine‐monophosphate (cGMP) transduction pathway which is known to regulate axonal growth and neural migration. Here, we present an experimental model in which we study the effect of NO on CNS regeneration in flat‐fillet locust embryo preparations in culture after crushing the connectives between abdominal ganglia. Using whole‐mount immunofluorescence, we examine the morphology of identified serotonergic neurons, which send a total of four axons through these connectives. After injury, these axons grow out again and reach the neighboring ganglion within 4 days in culture. We quantify the number of regenerating axons within this period and test the effect of drugs that interfere with NO action. Application of exogenous NO or cGMP promotes axonal regeneration, whereas scavenging NO or inhibition of soluble guanylyl cyclase delays regeneration, an effect that can be rescued by application of external cGMP. NO‐induced cGMP immunostaining confirms the serotonergic neurons as direct targets for NO. Putative sources of NO are resolved using the NADPH‐diaphorase technique. We conclude that NO/cGMP promotes outgrowth of regenerating axons in an insect embryo, and that such embryo‐culture systems are useful tools for studying CNS regeneration. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Hox genes and the regulation of movement in Drosophila
Authors: Dixit Richa , VijayRaghavan K. , Bate Michael
Published: November 2007

Many animals show regionally specialized patterns of movement along the body axis. In vertebrates, spinal networks regulate locomotion, while the brainstem controls movements of respiration and feeding. Similarly, amongst invertebrates diversification of appendages along the body axis is tied to the performance of characteristically different movements such as those required for feeding, locomotion, and respiration. Such movements require locally specialized networks of nerves and muscles. Here we use the regionally differentiated movements of larval crawling in Drosophila to investigate how the formation of a locally specialized locomotor network is genetically determined. By loss and gain of function experiments we show that particular Hox gene functions are necessary and sufficient to dictate the formation of a neuromuscular network that orchestrates the movements of peristaltic locomotion. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Organophosphorus pesticide exposure decreases sperm quality: association between sperm parameters and urinary pesticide levels
Authors: Recio‐Vega Rogelio , Ocampo‐Gómez Guadalupe , Borja‐Aburto Victor H. , Moran‐Martínez Javier , Cebrian‐Garcia Mariano E.
Published: November 2007

Several studies have suggested that human semen quality has declined over the past decades and some of them have associated it with occupational exposure to pesticides. However, most of these studies have not been associated with a reliable exposure level and have been designed mostly as cross‐sectional studies. The present work evaluates, in a longitudinal follow‐up study, the effect of organophosphate pesticides (OP) at three occupational exposure levels on semen quality. In addition, the study examined the association between OP urinary levels and sperm parameters in exposed and unexposed workers. A total of 139 semen samples from 52 volunteers were assessed. Urinary OP levels were measured by gas‐liquid chromatography.

The results revealed that the poorest semen quality was found among the subjects with the highest OP exposure and the highest urinary OP levels. Seasonal variations in sperm concentration and sperm count were registered.

The results showed a significant decrease in total sperm count among subjects with the highest exposure to OP. Further studies assessing the effects of OP on male reproductive health should be controlled by the variability in human sperm parameters, sperm seasonality, spermatogenesis time and the changing OP exposure level in men highly exposed to OP. Copyright © 2007 John Wiley & Sons, Ltd.
Reduced expression of MAb6B4 epitopes on chondroitin sulfate proteoglycan aggrecan in perineuronal nets from cerebral cortices of SAMP10 mice: A model for age‐dependent neurodegeneration
Authors: Saitoh Yuko , Matsui Fumiko , Chiba Yoichi , Kawamura Noriko , Keino Hiromi , Satoh Mamoru , Kumagai Naoko , Ishii Sanae , Yoshikawa Keisuke , Shimada Atsuyoshi , Maeda Nobuaki , Oohira Atsuhiko , Hosokawa Masanori
Published: November 2007

The accelerated senescence‐prone SAMP10 mouse strain is a model for age‐dependent neurodegeneration and is characterized by brain atrophy and deficits in learning and memory. Because perineuronal nets play an important role in the synaptic plasticity of adult brains, we examined the distributions of molecules that constitute perineuronal nets in SAMP10 mouse brain samples and compared them with those in control SAMR1 mouse samples. Proteoglycan‐related monoclonal antibody 6B4 (MAb6B4) clearly immunostained perineuronal nets in SAMR1 mice cortices, but the corresponding immunostaining in SAMP10 mice was very faint. MAb6B4 recognizes phosphacan/PTPζ in immature brains. However, this antibody recognized several protein bands, including a 400‐kDa core glycoprotein from chondroitin sulfate proteoglycan in homogenates of mature cortices from SAMR1 mice. The 400‐kDa band was also recognized by antiaggrecan antibodies. The aggrecan core glycoprotein band was also detectable in samples from SAMP10 mice, but this glycoprotein was faintly immunostained by MAb6B4. Because MAb6B4 recognized the same set of protein bands that the monoclonal antibody Cat‐315 recognized in mature cerebral cortices of SAMR1 mice, the MAb6B4 epitope appears to be closely related to that of Cat‐315 and presumably represents a novel type of oligosaccharide that attaches to aggrecans. The Cat‐315 epitope colocalized with aggrecan in perineuronal nets from SAMR1 mouse brain samples, whereas its expression was prominently reduced in SAMP10 mouse brain samples. The biological significance of the MAb6B4/Cat‐315 epitope in brain function and its relationship to the neurodegeneration and learning disabilities observed in SAMP10 mice remain to be elucidated. © 2007 Wiley‐Liss, Inc.
Macromol. Chem. Phys. 23/2007
Authors: Malik Muhammad Imran , Trathnigg Bernd , Kappe C. Oliver
Published: November 2007

Front Cover: PEO‐block‐PPO diblock copolymers are synthesized by microwave accelerated anionic ring opening polymerization of propylene oxide. The products are characterized by size exclusion chromatography with dual detection and liquid chromatography at critical conditions (see picture). Special emphasis is devoted to detection and quantification of side products in order to minimize them by optimized reaction conditions. Further details can be found in the article by M. I. Malik, B. Trathnigg,* and C. O. Kappe on page 2510. The cover page is sponsored by the Higher Education Commission of Pakistan.
Abnormal vibration‐induced illusion of movement in idiopathic focal dystonia: An endophenotypic marker?
Authors: Frima Nafsika , Nasir Jamal , Grünewald Richard A.
Published: November 2007

The frequency of symptomatic dystonia in relatives of patients with idiopathic focal dystonia (IFD) is higher than expected from epidemiologic studies implying that genetic factors may be involved. Perception of the vibration‐induced illusion of movement (VIIM) is subnormal in patients with IFD compared with healthy volunteers and the abnormality corrects with volitional fatigue of the vibrated arm. The aim of the study was to establish the heritability of the abnormality of VIIM. The perception of illusion of movement elicited by vibration of the biceps brachii tendon before and after fatigue of the muscles was investigated in 30 patients with torticollis, 57 of their first degree relatives, and 19 healthy volunteers. VIIM did not change after fatigue in healthy controls. Before fatiguing the muscles, patients' perception of VIIM was less than healthy controls, (P < 0.01, unpaired t‐test). After fatigue, the illusion of movement perceived by patients increased, so that it did not differ any more from that of the healthy control subjects (P < 0.05, repeated measures ANOVA). First degree relatives' response to vibration varied; 45% of parents, 60.7% of siblings, and 63.6% of children had an “abnormal” response to vibration compared with 21% of healthy volunteers. In contrast to patients' response, the “abnormality” did not correct after volitional fatigue of the vibrated arm. The results suggest that abnormal VIIM may represent an endophenotypic marker for IFD, which interacts with other factors including central motor learning and compensation mechanisms in the expression of the dystonic phenotype. © 2007 Movement Disorder Society
Relationships between MR transverse relaxation parameters R, R2 and R and hepatic iron content in thalassemic mice at 1.5 T and 3 T
Authors: Song Ruitian , Lin Wei , Chen Qiukan , Asakura Toshio , Wehrli Felix W. , Song Hee Kwon
Published: November 2007

Assessment of hepatic iron concentration is important in the management of patients with thalassemia. The goal of this study was to investigate the relationships between the three MR transverse relaxation rates, R, R2, and R, and hepatic iron content in a mouse model of thalassemia at 1.5 and 3 T field strengths. A GESFIDE (gradient‐echo sampling of free induction decay and echo) pulse sequence was used to measure the three parameters efficiently in a single scan in a study examining the livers of normal and thalassemic mice, including a subgroup of the latter that were subjected to periodic transfusions. The results showed that R, R2 and R all correlated closely with liver iron concentration at both 1.5 T and 3 T, with correlation coefficients ranging from 0.72 to 0.79. High degrees of correlation (r = 0.93–0.99) were also observed among the three MR parameters at both field strengths. It can be concluded that the three rates could all be effective for assessing hepatic iron concentration and that imaging at higher fields may not offer any advantages over that at lower fields. Copyright © 2007 John Wiley & Sons, Ltd.
Models and heuristics for a minimum arborescence problem
Authors: Duhamel Christophe , Gouveia Luis , Moura Pedro , Souza Mauricio
Published: November 2007

The Minimum Arborescence problem (MAP) consists of finding a minimum cost arborescence in a directed graph. This problem is NP‐Hard and is a generalization of two well‐known problems: the Minimum Spanning Arborescence Problem (MSAP) and the Directed Node Weighted Steiner Tree Problem (DNWSTP). We start the model presentation in this paper by describing four models for the MSAP (including two new ones, using so called “connectivity” constraints which forbid disconnected components) and we then describe the changes induced on the polyhedral structure of the problem by the removal of the spanning property. Only two (the two new ones) of the four models for the MSAP remain valid when the spanning property is removed. We also describe a multicommodity flow reformulation for the MAP that differs from well‐known multicommodity flow reformulations in the sense that the flow conservation constraints at source and destination are replaced by inequalities. We show that the linear programming relaxation of this formulation is equivalent to the linear programming relaxation of the best of the two previous valid formulations and we also propose two Lagrangean relaxations based on the multicommodity flow reformulation. From the upper bound perspective, we describe a constructive heuristic as well as a local search procedure involving the concept of key path developed earlier for the Steiner Tree Problem. Numerical experiments taken from instances with up to 400 nodes are used to evaluate the proposed methods. © 2007 Wiley Periodicals, Inc. NETWORKS, 2008
Anti‐PSMA immunotoxin as novel treatment for prostate cancer? High and specific antitumor activity on human prostate xenograft tumors in SCID mice
Authors: Wolf Philipp , Alt Karen , Bühler Patrick , Katzenwadel Arndt , Wetterauer Ulrich , Tacke Marlene , Elsässer‐Beile Ursula
Published: November 2007

BACKGROUND

Expression of the prostate specific membrane antigen (PSMA) is highly restricted to prostate epithelial cells. Therefore, toxin‐based immunotherapy against this antigen may represent an alternative therapeutic option for prostate cancer. For these purposes, the effects of the recombinant anti‐PSMA immunotoxin A5‐PE40 on prostate tumor growth were investigated in vitro and in vivo.

METHODS

The in vitro binding and cytotoxicity of A5‐PE40 were tested on the PSMA‐expressing prostate cancer cell line C4‐2 and on the PSMA‐negative cell line DU145 by flow cytometry and WST assays. The binding of the immunotoxin to SCID mouse xenografts and to various mouse organs was examined by Western blot analysis. In vivo, the antitumor activity of the immunotoxin was tested by injecting A5‐PE40 in mice bearing C4‐2 or DU145 xenografts.

RESULTS

In vitro, a specific binding of A5‐PE40 to C4‐2 cells could be shown with a concentration‐dependent cytotoxicity (IC50 value = 220 pM). In the next step, a specific binding of the immunotoxin to C4‐2 xenografts could be demonstrated. In contrast, no binding on mouse organs expressing high homologous mouse PSMA was found. The treatment of mice with C4‐2 tumors caused a significant inhibition of tumor growth in vivo, whereas DU145 xenografts remained totally unaffected.

CONCLUSIONS

A5‐PE40 represents a recombinant anti‐PSMA immunotoxin with potent antitumor activity in mice bearing human prostate cancer xenograft tumors. Therefore, A5‐PE40 could be a promising candidate for therapeutic applications in patients with prostate cancer. Prostate 68: 129–138, 2008. © 2007 Wiley‐Liss, Inc.
p‐type conducting ZnO:P microwires prepared by direct carbothermal growth
Authors: Cao B. Q. , Lorenz M. , Brandt M. , von Wenckstern H. , Lenzner J. , Biehne G. , Grundmann M.
Published: November 2007

Phosphorous‐doped (ZnO:P) and undoped ZnO wires with diameter of several micrometers and length of several hundred micrometers were thermally grown directly on phosphorus pentoxide doped and undoped ZnO:graphite targets, respectively. The cathodoluminescence spectra of single ZnO:P microwires show three typical acceptor‐related emissions which are attributed to (A0, X), (e, A0), and DAP. Three‐terminal, gate voltage dependent electrical measurements of back‐gate field effect transistors with the microwires as channels indicate reproducibly that undoped ZnO and ZnO:P microwires are n‐type and p‐type conductive, respectively. The p‐type conductivity was found to be stable over more than six months. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Truths, Facts and Values
Authors: Reinhardt Lloyd
Published: November 2007

The paper suggests a revival of the 17th century distinction between truths of reason and truths of fact. Some points are made which seem to me show it obviously false that a fact is merely a true proposition. Truths of fact, contingent truths, are rightly seen as corresponding to facts. Other truths, including ethical truths of right and wrong are, if true, necessarily true. In general, necessarily true statements, including those of mathematics are wrongly construed as factual.

Ethics and aesthetics, it is maintained, can be construed as noncognitive; but not because claims in these domains are other than claims to truth. They are, in large part, not claims to knowledge, which does not bar them from being claims to truth.
Authors: Read Rupert
Published: November 2007

This book is a piece of philosophical work of extremely high intellectual quality. Its purpose is to defend in detail a ‘resolute’ reading of the Tractatus. It succeeds in this aim. It thus accomplishes something that has not yet been accomplished even by Conant or Diamond. It is therefore a major contribution to ‘Wittgenstein studies’, to contemporary philosophy and to the philosophical history of recent philosophy. (It has significant implications, for instance, for the work of Freudians, Sartreans, Griceans, Davidsonians.)
On a Supposed Contradiction in Hume
Authors: Botros Sophie
Published: November 2007

One of the most powerful arguments in meta-ethics today is that of Treatise, Book 3, in which Hume seeks to show that morality's practical influence precludes its being based on reason. H.O. Mounce, in his review1 of my Hume, Reason and Morality: A Legacy of Contradiction,2 rejects my central contention that this argument contains a contradiction. This review is however flawed on several counts.
Theory of capillary-induced interactions beyond the superposition approximation
Authors: Domínguez Alvaro , Oettel Martin , Dietrich S.
Published: November 2007

Within a general theoretical framework, we study the effective, deformation-induced interaction between two colloidal particles trapped at a fluid interface in the regime of small deformations. In many studies, this interaction has been computed with the ansatz that the actual interface configuration for the pair is given by the linear superposition of the interface deformations around the single particles. Here, we assess the validity of this approach and compute the leading term of the effective interaction for a large interparticle separation beyond this so-called superposition approximation. As an application, we consider the experimentally relevant case of interface deformations owing to the electrostatic field emanating from charged colloidal particles. In mechanical isolation, i.e., if the net force acting on the total system consisting of the particles plus the interface vanishes, the superposition approximation is actually invalid. The effective capillary interaction is governed by contributions beyond this approximation and turns out to be attractive. For sufficiently small surface charges on the colloids, such that linearization is strictly valid, and at asymptotically large separations, the effective interaction does not overcome the direct electrostatic repulsion between the colloidal particles.
The permanent electric dipole moment of chromium monodeuteride, CrD
Authors: Chen Jinhai , Steimle Timothy C. , Merer Anthony J.
Published: November 2007

A number of low-N lines of the XΣ+6←AΣ+6(0,0) band of chromium monodeuteride, CrD, have been recorded at near the natural linewidth limit by high resolution laser excitation spectroscopy of a supersonic molecular beam sample. The shifts and splitting of these lines caused by a static electric field have been analyzed to give the permanent electric dipole moments of the XΣ+6(υ=0) and AΣ+6(υ=0) states as 3.510(33) and 1.153(3)D, respectively. The dipole moment of the AΣ+6(υ=0) state can be measured with higher precision because of some interesting near degeneracies in its level structure. The trends in the observed dipole moments for the first-row transition metal monohydrides are rationalized and compared with theoretical predictions.
Stationary current generated from photocycle of a hybrid bacteriorhodopsin/quantum dot bionanosystem
Authors: Li Rui , Li Chang Ming , Bao Haifeng , Bao Qiaoliang , Lee Vee S.
Published: November 2007

Bacteriorhodopsin (bR) is a promising biomaterial for broad potential applications in optical and optoelectronic devices. Upon the original photochemical cycle of bR, for the first time we construct a hybrid bR/quantum dot (QD) bionanosystem and a stationary current is generated from the modified photocycle. We propose a model to explain that QDs could act as nanoscaled light sources embedded in bR to assist its generation of a stationary photocurrent, which is completely different from the reported transient spikes from the bR’s photocycle. It opens the horizon for optical devices other than those reported up to date.
Measuring permeability of porous materials at low frequency range via acoustic transmitted waves
Authors: Fellah Z. E. A , Fellah M. , Mitri F. G. , Sebaa N. , Depollier C. , Lauriks W.
Published: November 2007

An acoustical transmission method is proposed for measuring permeability of porous materials having rigid frame. Permeability is one of the several parameters required by acoustical theory to characterize porous materials such as plastic foams and fibrous or granular materials. The proposed method is based on a temporal model of the direct and inverse scattering problem for the diffusion of transient low frequency waves in a homogeneous isotropic slab of porous material having a rigid frame. This time domain model of wave propagation was initially introduced by the authors [Z.E.A Fellah and C. Depollier, J. Acoust. Soc. Am. 107, 683 (2000)]. The viscous losses of the medium are described by the model devised by Johnson et al. [J. Fluid. Mech. 176, 379 (1987)]. Reflection and transmission scattering operators for a slab of porous material are derived from the responses of the medium to an incident acoustic pulse. The permeability is determined from the expressions of these operators. Experimental and numerical validation results of this method are presented. This method has the advantage of being simple, rapid, and efficient.
Tunneling through inhomogeneous delta barriers as diffraction and scattering
Authors: Bezák Viktor
Published: November 2007

We present a general theory of the quantum-mechanical tunneling through an inhomogeneous planar delta barrier. The delta barrier means that the potential energy is proportional to the Dirac delta function in the direction perpendicular to the plane of the barrier. The inhomogeneity of the delta barrier means that the delta function is multiplied by a non-negative function, different from a constant, of lateral coordinates. We assume that this function, being the barrier strength, may be arbitrary. To exemplify our theory, we consider delta barriers that are made inhomogeneous by embedding equal circular windows in the barrier plane, assuming that the barriers are homogeneous both inside and outside the windows. (The value of the barrier strength is taken higher by the side of the windows than inside the windows.) With the inhomogeneous delta barriers of this kind, we show how the tunneling theory is related to the theory of diffraction and scattering. Although our general solution of the problem is new in the context of the tunneling theory, it is essentially based on a method which was used by Kirchhoff in the 19th century in the theory of waves.
Strong transport reduction in the helical core of the reversed-field pinch
Authors: Annibaldi S. V. , Bonomo F. , Pasqualotto R. , Spizzo G. , Alfier A. , Buratti P. , Piovesan P. , Terranova D.
Published: November 2007

An explanation of the strong heating observed in the core of a reversed-field pinch in the quasi-single-helicity state is presented. A magnetic island is formed, in which the heat transport coefficient is much smaller than in the surrounding chaotic sea, because of the formation of well defined magnetic surfaces. The values of the thermal conductivity obtained with the M1TEV [F. Porcelli et al., Phys. Rev. Lett 82, 1458 (1999)] two-dimensional transport code are in very good agreement with the estimates of the ion diffusion coefficient inside the island, given by a Hamiltonian guiding center code. Moreover, the values of thermal conductivity are in the tokamak range, and are consistent with the peak temperatures measured in the Reversed Field eXperiment [P. Sonato et al., Fusion Eng. Des. 66–68, 161 (2003)] at Consorzio RFX, Padova, Italy. The effect of the island width and the different powers deposited inside the island on the final temperature peak are also investigated.
Hydrodynamics studies of direct-drive cone-in-shell, fast-ignitor targets on OMEGA
Authors: Stoeckl C. , Boehly T. R. , Delettrez J. A. , Hatchett S. P. , Frenje J. A. , Glebov V. Yu. , Li C. K. , Miller J. E. , Petrasso R. D. , Séguin F. H. , Smalyuk V. A. , Stephens R. B. , Theobald W. , Yaakobi B. , Sangster T. C.
Published: November 2007

Experiments have been performed on the OMEGA Laser Facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] to study the hydrodynamics of directly driven cone-in-shell, fast-ignitor targets. A 35° or 70° opening-angle gold cone was inserted into spherical plastic shells of ∼24-μm thickness and ∼870-μm diameter, which were imploded with up to 21kJ of 351-nm laser light. A backlighter was used on some experiments to compare the fuel assembly of targets with or without a high-pressure fill gas. The shock breakthrough to the inside of the cone, where the ultrafast laser propagates in integrated fast-ignitor experiments, was studied using a streaked optical pyrometer. No plasma was seen inside the cone before the assembled core reached peak compression.
Method for rapid determination of ion gauge sensitivity factors
Authors: Peng C. Y. , Woodworth A. A. , Stinespring C. D.
Published: November 2007

In ultrahigh vacuum thin film growth processes using gas phase growth precursors, the pressure of the gas at or near the substrate is a critical parameter since it is directly related to the collision frequency of the precursor with the substrate and ultimately to the growth rate. These pressures are usually measured using a nude Bayrd-Alpert-type ion gauges, which are generally calibrated for nitrogen. Consequently, it is necessary to know the ion gauge sensitivity factor that relates the measured pressure to the actual pressure of the growth precursor. The purpose of this article is to describe a simple method to obtain such sensitivity factors. This method uses a simple gas manifold comprised of equipment commonly found in laboratory settings where ultrahigh vacuum work is performed. Results are reported for dimethyl silane, monomethyl silane, methane, and hydrogen. The gauge sensitivity factors for the latter two gases are known and, therefore, provide a basis for validating the method.
Spot-size evolution of laser beam propagating in plasma embedded in axial magnetic field
Authors: Jha Pallavi , Mishra Rohit K. , Upadhyay Ajay K. , Raj Gaurav
Published: November 2007

In this paper, evolution of the spot size of an intense laser beam propagating in axially magnetized, cold, underdense plasma has been studied. The effect of longitudinal magnetization on the laser spot for a left as well as a right circularly polarized laser beam has been considered. Critical power for nonlinear self-focusing of the beam in magnetized plasma has been obtained.
Surface modes of a sessile water drop: An optical tweezer based study
Authors: Ghosh Shankar , Sharma Prerna , Bhattacharya S.
Published: November 2007

A high-precision method to study the dynamics of two-fluid interfaces using an optical tweezer and a phase-sensitive detection technique are described. The disturbances set up at the interface are studied by analyzing the motion of an optically trapped particle in the bulk of the fluid, i.e., away from the interface. The usefulness of the technique is demonstrated for the well-known problem of a horizontally vibrated sessile liquid drop. The vibrational modes of the liquid drop excited by sinusoidally vibrating the support in a horizontal plane appear as resonances in the motion of the trapped particle. The nature of the resonance is studied in detail by measuring the real part, the imaginary part, and the phase response of the motion of the particle as a function of the “effective” size of the liquid drop. Excellent quantitative agreement with the theoretically predicted values of the eigenfrequencies and damping of the surface modes is obtained.
A braided look at Green ansatz for parabosons
Authors: Kanakoglou K. , Daskaloyannis C.
Published: November 2007

Bosons and parabosons are described as associative superalgebras, with an infinite number of odd generators. Bosons are shown to be a quotient superalgebra of parabosons, establishing thus an even algebra epimorphism which is an immediate link between their simple modules. Parabosons are a super-Hopf algebra. The super-Hopf algebraic structure of parabosons, combined with the projection epimorphism previously stated, provides a braided interpretation of the Green ansatz device and of the parabosonic Fock-like representations. This braided interpretation combined with an old problem leads to the construction of straightforward generalizations of the Green ansatz.
Comment on “A note on the infimum problem of Hilbert space effects” [J. Math. Phys. 47, 102103 (2006)]
Authors: Gheondea Aurelian
Published: November 2007

We show that the two main results of the article [J. Math. Phys. 47, 102103 (2006)] have very short proofs as direct consequences of the solution to the infimum problem for bounded non-negative operators in a Hilbert space given by T. Ando [Analytic and Geometric Inequalities and Applications, Mathematical Applications Vol. 478 (Kluwer Academic, Dordrecht, 1999)] and a formula for the shorted operator obtained by H. Kosaki [“Remarks on Lebesgue-type decomposition of positive operators,” J. Oper. Theory 11, 137–143 (1984)].
Growth of GaN film on 150mm Si (111) using multilayer AlN∕AlGaN buffer by metal-organic vapor phase epitaxy method
Authors: Lin Kung-Liang , Chang Edward-Yi , Hsiao Yu-Lin , Huang Wei-Ching , Li Tingkai , Tweet Doug , Maa Jer-Shen , Hsu Sheng-Teng , Lee Ching-Ting
Published: November 2007

High quality GaN film was successfully grown on 150mm Si (111) substrate by metal-organic vapor phase epitaxy method using AlN multilayer combined with graded AlGaN layer as buffer. The buffer layer structure, film quality, and film thickness are critical for the growth of the crack-free GaN film on Si (111) substrate. Using multilayer AlN films grown at different temperatures combined with graded Al1−xGaxN film as the buffer, the tensile stress on the buffer layer was reduced and the compressive stress on the GaN film was increased. As a result, high quality 0.5μm crack-free GaN epitaxial layer was successfully grown on 6in. Si substrate.
Specialised Higher-Level Mechanisms for Facial-Symmetry Perception: Evidence from Orientation-Tuning Functions
Authors: Rhodes Gillian , Peters Marianne , Ewing Louise A
Published: November 2007

Bilateral symmetry is important in many perceptual analyses from low-level figure—ground segmentation to higher-level face and object perception. Despite the success of low-level, image-based symmetry-detection models, these may not provide a complete account of symmetry perception. Better symmetry detection and stronger preferences for symmetry in upright faces than comparable patterns (eg inverted faces) that do not engage specialised face-coding mechanisms suggest a contribution of higher-level mechanisms to symmetry perception. We replicated better symmetry detection and stronger symmetry preferences for upright than inverted faces in experiment 1, and examined their orientation tuning in more detail in experiment 2. Decreasing performance as faces are mis-oriented away from the canonical upright orientation is the signature of specialised face-processing mechanisms, which are engaged less effectively as faces are mis-oriented. Lower-level symmetry-detection mechanisms, which operate better with vertical than horizontal, and horizontal than oblique, axes of symmetry would produce a W-shaped orientation-tuning function. Identical orientation-tuning functions were obtained for symmetry detection and preferences. Both declined with increasing mis-orientation over the 0°–135° range, consistent with a contribution from specialised face-coding mechanisms. Both increased from 135° to 180°, consistent with reliance on lower-level image-based mechanisms for severely mis-oriented faces. Taken together, the results implicate specialised, higher-level mechanisms in the detection of, and preference for, facial symmetry.
Silencing of OB-RGRP in mouse hypothalamic arcuate nucleus increases leptin receptor signaling and prevents diet-induced obesity
Authors: Couturier Cyril , Sarkis Chamsy , Séron Karin , Belouzard Sandrine , Chen Patty , Lenain Aude , Corset Laetitia , Dam Julie , Vauthier Virginie , Dubart Anne , Mallet Jacques , Froguel Philippe , Rouillé Yves , Jockers Ralf
Published: November 2007

Obesity is a major public health problem and is often associated with type 2 diabetes mellitus, cardiovascular disease, and metabolic syndrome. Leptin is the crucial adipostatic hormone that controls food intake and body weight through the activation of specific leptin receptors (OB-R) in the hypothalamic arcuate nucleus (ARC). However, in most obese patients, high circulating levels of leptin fail to bring about weight loss. The prevention of this “leptin resistance” is a major goal for obesity research. We report here a successful prevention of diet-induced obesity (DIO) by silencing a negative regulator of OB-R function, the OB-R gene-related protein (OB-RGRP), whose transcript is genetically linked to the OB-R transcript. We provide
in vitro
evidence that OB-RGRP controls OB-R function by negatively regulating its cell surface expression. In the DIO mouse model, obesity was prevented by silencing OB-RGRP through stereotactic injection of a lentiviral vector encoding a shRNA directed against OB-RGRP in the ARC. This work demonstrates that OB-RGRP is a potential target for obesity treatment. Indeed, regulators of the receptor could be more appropriate targets than the receptor itself. This finding could serve as the basis for an approach to identifying potential new therapeutic targets for a variety of diseases, including obesity.
Disulfide bond influence on protein structural dynamics probed with 2D-IR vibrational echo spectroscopy
Authors: Ishikawa Haruto , Kim Seongheun , Kwak Kyungwon , Wakasugi Keisuke , Fayer Michael D.
Published: November 2007

Intramolecular disulfide bonds are understood to play a role in regulating protein stability and activity. Because disulfide bonds covalently link different components of a protein, they influence protein structure. However, the effects of disulfide bonds on fast (subpicosecond to ≈100 ps) protein equilibrium structural fluctuations have not been characterized experimentally. Here, ultrafast 2D-IR vibrational echo spectroscopy is used to examine the constraints an intramolecular disulfide bond places on the structural fluctuations of the protein neuroglobin (Ngb). Ngb is a globin family protein found in vertebrate brains that binds oxygen reversibly. Like myoglobin (Mb), Ngb has the classical globin fold and key residues around the heme are conserved. Furthermore, the heme-ligated CO vibrational spectra of Mb (Mb-CO) and Ngb (Ngb-CO) are virtually identical. However, in contrast to Mb, human Ngb has an intramolecular disulfide bond that affects its oxygen affinity and protein stability. By using 2D-IR vibrational echo spectroscopy, we investigated the equilibrium protein dynamics of Ngb-CO by observing the CO spectral diffusion (time dependence of the 2D-IR line shapes) with and without the disulfide bond. Despite the similarity of the linear FTIR spectra of Ngb-CO with and without the disulfide bond, 2D-IR measurements reveal that the equilibrium sampling of different protein configurations is accelerated by disruption of the disulfide bond. The observations indicate that the intramolecular disulfide bond in Ngb acts as an inhibitor of fast protein dynamics even though eliminating it does not produce significant conformational change in the protein's structure.
Temperature-related birth sex ratio bias in historical Sami: warm years bring more sons
Authors: Helle Samuli , Helama Samuli , Jokela Jukka
Published: November 2007

The birth sex ratio of vertebrates with chromosomal sex determination has been shown to respond to environmental variability, such as temperature. However, in humans the few previous studies on environmental temperature and birth sex ratios have produced mixed results. We examined whether reconstructed annual mean temperatures were associated with annual offspring sex ratio at birth in the eighteenth to nineteenth century Sami from northern Finland. We found that warm years correlated with a male-biased sex ratio, whereas a warm previous year skewed sex ratio towards females. The net effect of one degree Celsius increase in mean temperature during these 2 years corresponded to approximately 1% more sons born annually. Although the physiological and ecological mechanisms mediating these effects and their evolutionary consequences on parental fitness remain unknown, our results show that environmental temperature may affect human birth sex ratio.
Aggressive and non-aggressive personalities differ in oxidative status in selected lines of mice (
Mus musculus
)
Authors: Costantini David , Carere Claudio , Caramaschi Doretta , Koolhaas Jaap M
Published: November 2007

Mice selected for aggression and coping (long attack latency (LAL), reactive coping strategy; short attack latency (SAL), pro-active coping strategy) are a useful model for studying the physiological background of animal personalities. These mice also show a differential stress responsiveness, especially in terms of hypothalamic–pituitary–adrenal axis reactivity, to various challenges. Since the stress response can increase the production of reactive oxygen species, we predicted that the basic oxidative status of the lines could differ. We found that LAL showed higher serum antioxidant capacity (OXY) than SAL, while no differences emerged for reactive oxygen metabolites (ROMs) or the balance between ROMs and OXY, reflecting oxidative stress. Moreover, the lines showed inverse relationships between ROMs or OXY and body mass corrected for age. The results indicate that variation in oxidative status is heritable and linked to personality. This suggests that different animal personalities may be accompanied by differences in oxidative status, which may predict differences in longevity.
Structure of the scalar field around unidirectional circular cylinders
Authors: Rylko Natalia
Published: November 2007

We study transport properties of equal infinite unidirectional circular cylinders that are arbitrarily distributed in a uniform host. The problem is reduced to a conjugation problem for the two-dimensional Laplace equation. The flux is written exactly in the form of a power series in Bergman's contrast parameter. Asymptotic formulae for the flux are deduced for densely packed inclusions. These formulae involve two small parameters: the ratio of the distance between the close discs to their radius and a dimensionless parameter that characterizes the degree of perfect conductor/isolator. Validity of the structural approximation is discussed.
Cheating honeybee workers produce royal offspring
Authors: Jordan Lyndon A , Allsopp Michael H , Oldroyd Benjamin P , Wossler Theresa C , Beekman Madeleine
Published: November 2007

The Cape bee (
Apis mellifera capensis
) is unique among honeybees in that workers can lay eggs that instead of developing into males develop into females via thelytokous parthenogenesis. We show that this ability allows workers to compete directly with the queen over the production of new queens. Genetic analyses using microsatellites revealed that 23 out of 39 new queens produced by seven colonies were offspring of workers and not the resident queen. Of these, eight were laid by resident workers, but the majority were offspring of parasitic workers from other colonies. The parasites were derived from several clonal lineages that entered the colonies and successfully targeted queen cells for parasitism. Hence, these parasitic workers had the potential to become genetically reincarnated as queens. Of the daughter queens laid by the resident queen, three were produced asexually, suggesting that queens can ‘choose’ to produce daughter queens clonally and thus have the potential for genetic immortality.