bluuebunny/crossref_metadata_2025 huggingface dataset:
Human ocular onchocerciasis caused byOnchocerca lupi(Spirurida, Onchocercidae) in Iran
Authors: Mowlavi G. , Farzbod F. , Kheirkhah A. , Mobedi I. , Bowman D.D. , Naddaf S.R.
Published: February 2013

Cases of canine onchocerciasis caused byOnchocerca lupiare increasingly reported from Europe and the western United States of America. The zoonotic role of this parasite had already been suspected in Europe as the clinical signs and histopathology seen in two ocular cases from Albania and the Crimean region were very similar to those of canine ocular onchocerciasis. In the most recent reports of human onchocerciasis,O. lupihas been morphologically and molecularly identified as the causative agent of ocular infestation in two patients from Turkey, and one patient from Tunisia. Here, we report an additional case of nodular lesions involving two, and possibly more, immature worms in a patient from Iran. The parasite was found to belong to the genusOnchocercabased on morphological features and the species was confirmed asO. lupifrom a partial sequence analysis of 12S ribosomal DNA.
Isolated primary frontal sinus aspergillosis: role of endonasal endoscopic approach
Authors: Gupta R , Gupta A K
Published: February 2013

Background:

Frontal sinus involvement in aspergillosis associated with the nose and paranasal sinuses is a common occurrence, but the incidence of primary frontal sinus aspergillosis is rare, and there are few reports in the English literature.

Objective:

This study aimed to evaluate the role of the endonasal endoscopic surgical approach for isolated primary frontal sinus aspergillosis.

Method:

This paper describes a retrospective study of 16 cases of primary frontal sinus aspergillosis. The patients had presented to the out-patient services of the Department of Otolaryngology and Head and Neck Surgery, Post Graduate Institute of Medical Education and Research, Chandigarh, India, between January 1999 and July 2011.

Results:

The overall success rate of the endonasal endoscopic approach was 82.25 per cent. The disease recurred in three patients and was subsequently managed using the modified Lothrop procedure.

Conclusion:

Minimally invasive endonasal endoscopic sinus surgery was found to be an effective and a safe approach for managing primary frontal sinus aspergilloma, even in cases with larger bony defects involving the posterior table of the frontal sinus.
So now what? Effects of retirement on civic engagement
Authors: VAN DEN BOGAARD LEVI , HENKENS KÈNE , KALMIJN MATTHIJS
Published: February 2013

Retirement is an event that often brings about great changes in a person's personal and social life. For many people, work is not only a way to fill time and earn money, but also important for their identity and meaning in life. After retirement, these benefits of work are lost, and it is expected that people will seek substitutes for this loss. This paper focuses on the effects of retirement on informal civic activities such as the support given to family and friends as well as more formal types such as volunteering and organisational involvement. Using two waves from the Netherlands Kinship Panel Study, a conditional change model is employed. Two groups are compared: men and women who kept working, and men and women who retired. Results show that following retirement, people appear to change the nature of some relationships by providing more instrumental support. Furthermore, retirees seem to start spending more time volunteering after retirement, and they increase their organisational memberships. Implications, strengths and limitations of the study are discussed.
Troubling genre, ethnicity and geopolitics in Taiwanese American independent rock music
Authors: Hsu Wendy F.
Published: February 2013

This paper examines the performances of Taiwanese American Jack Hsu and his New Jersey-based progressive erhu-rock band The Hsu-nami, in transnational contexts fraught by ethnonationalism and race. Through an ethnographic approach, this paper highlights the band's depoliticising practice to deflect the geopolitics across the Taiwan Strait. It also discusses how Hsu adapts the musical and gender ideologies in rock music culture to diffuse racial ideologies surrounding his ethnicity and instrument. Finally, an analysis of the band's deployment of cultural diplomacy discusses pragmatic multiculturalism, a mode that reflects the tension between rock music's ostensibly counter-cultural front and its commercial foundation.
Association of congenital descending aorto–left atrial fistula with the aortopulmonary window and atrial septal defect
Authors: Sarkar Achyut K , Sanjeeva Naveenchandra G , Waghmare Nagesh S
Published: February 2013

We report a case of fistula between the descending aorta and the left atrium with associated aortopulmonary window and secundum atrial septal defect. No previous reports of such association have been found in the literature. A 5-month-old infant presented with heart failure from the age of 2 weeks. Echocardiography confirmed the presence of an aorto–left atrial fistula, aortopulmonary window, and atrial septal defect. The diagnosis was additionally supported by computed tomography. The entity aorto–left atrial fistula is rare. It is mostly acquired and usually between the ascending aorta and the right atrium or right ventricle or left ventricle. We do not know about all the associated anomalies, which have implications in management. There is a case report of ascending aorto–left atrial fistula associated with bicuspid aortic valve and anomalous origin of coronaries. Here we are reporting a case of descending aorto–left atrial fistula associated with aortopulmonary window.
Results of using cardiopulmonary bypass for spinal cord protection during surgical repair of complex aortic coarctation
Authors: Sandrio Stany , Karck Matthias , Gorenflo Matthias , Loukanov Tsvetomir
Published: February 2013

Background

The aim of this study was to evaluate the surgical treatment of complex aortic coarctation using partial cardiopulmonary bypass to increase the spinal cord protection.

Methods

A total of 15 patients (age range from 7 to 48 years) underwent coarctation repair through a left posterolateral thoracotomy with cardiopulmonary bypass. Cannulation was performed via the descending aorta and the main pulmonary artery. In all, six surgeries were performed under hypothermic circulatory arrest and nine repairs were performed under mild hypothermia. The clinical outcome regarding the development of restenosis, as well as major neurologic complication, was studied.

Results

There was no mortality. None of the patients developed paraplegia. Of the 15 patients, two developed a recurrent stenosis at the proximal anastomosis between the aortic arch and the aortic prothesis at a mean follow-up of 5.5 years. In the remaining 13 patients, echocardiography and magnetic resonance imaging showed no evidence of a significant gradient.

Conclusion

Complex aortic coarctation without hypoplasia of the proximal aortic arch and intra-cardiac anomalies can be repaired with low mortality and neurologic morbidity via a left thoracotomy using cardiopulmonary bypass. The use of cardiopulmonary bypass goes along with a low risk of spinal cord and lower body ischaemia and provides a sufficient amount of time for the anastomoses.
Rawlsian Public Reason and the Theological Framework of Martin Luther King's “Letter from Birmingham City Jail”
Authors: Dyer Justin Buckley , Stuart Kevin E.
Published: February 2013

The ideal of public reason, made prominent by John Rawls, has become a mainstay of discussions about the proper role of religious arguments in a politically liberal society. In particular, Rawls's theory of public reason requires citizens and public officials to refrain from appealing to comprehensive religious and philosophical doctrines in public deliberation on matters of basic justice and constitutional essentials. In this essay, we review the ways in which the public life of Martin Luther King, Jr. — with its frequent appeals to a comprehensive doctrine to justify disobedience to the law — represents a challenge to the ideal of public reason, and we consider several Rawlsian rejoinders. What is missing from the existing body of scholarship on public reason is a thorough analysis of King's philosophical and theological arguments, including the examples of legal injustice he offered in his celebrated “Letter from Birmingham Jail.” As we note, King's specific examples of unjust laws rely on a theological framework that bedevils the attempt to reconcile his Letter with the constructivist underpinnings of Rawls's theory of public reason. Indeed, Rawls is in something of a bind: either King's argument is not acceptable under the terms of public reason or public reason simply cannot limit contemporary public discourse in the way Rawls has in mind. We consider several possible Rawlsian arguments for the accommodation of King's theological rhetoric, but conclude that the Rawlsian idea of public reason remains deeply problematic.
Giving Up On the Founding: The Separation of Church and State and the Writing of Establishment Clause History
Authors: Grenda Christopher S.
Published: February 2013

Examination of the First Amendment's establishment clause in the post World War II period is unique in American constitutional interpretation because virtually all voices had agreed on one point, originalism. Few if any significant writers on the establishment clause had doubted the centrality of the founders' original intent for interpreting the clause's meaning. Yet this now has changed. Unlike their predecessors, leading advocates of church-state separation have now moved away from an original meaning interpretation of the establishment clause. Yet these separationists continue to try to ground their normative policy prescriptions in establishment clause mandates. They attempt this balancing act by employing narrative strategies of evolutionary processes in history. They do not simply track changes in constitutional doctrine, but characterize changes yielding greater separation between church and state through the nation's history as incipient in the Republic's founding, an originally inchoate church-state principle only fully formed through historical evolution. In the process, they sweep myriad separationist ideas into their progressively evolving narratives which have never been enunciated as law. Their accounts thus often reflect less an attempt to track historical developments in fundamental law than an attempt to construct fundamental law narratives. These attempts highlight persistent historical problems in the separationist endeavor that require attention if the evolutionary narratives of leading separationist are to shape the field of establishment clause history.
Zen and the Science of American Politics: Minority Religious Traditions and Political Engagement
Authors: Schoettmer Patrick
Published: February 2013

American Buddhism is a phenomenon that allows for the testing of a number of generally-held assumptions about how religion operates within the American context. Due to the fairly de-politicized character of the religion in the United States, Buddhism allows for the examination of religion-qua-religion insofar as its role in the political mobilization of believers. This study finds that Buddhist political engagement is driven in general by private religious practice rather than by communal or small-group religious participation, as social capital-oriented theories of religio-political engagement suggest. Furthermore, this appears likely to be due to the nature of Buddhist adherents in the United States (who are predominantly Caucasian converts to the faith and who enjoy a generally high socio-economic status.) Closer examination of the situation of Buddhists in the United States suggests that the resource-model of civic skill acquisition does hold among the most economically disadvantaged, but that other explanations help us better understand political engagement among more advantaged Buddhists.
Nanoparticles for Targeted Delivery of Antioxidant Enzymes to the Brain after Cerebral Ischemia and Reperfusion Injury
Authors: Yun Xiang , Maximov Victor D , Yu Jin , Zhu g , Vertegel Alexey A , Kindy Mark S
Published: February 2013

Stroke is one of the major causes of death and disability in the United States. After cerebral ischemia and reperfusion injury, the generation of reactive oxygen species (ROS) and reactive nitrogen species may contribute to the disease process through alterations in the structure of DNA, RNA, proteins, and lipids. We generated various nanoparticles (liposomes, polybutylcyanoacrylate (PBCA), or poly(lactide-co-glycolide) (PLGA)) that contained active superoxide dismutase (SOD) enzyme (4,000 to 20,000 U/kg) in the mouse model of cerebral ischemia and reperfusion injury to determine the impact of these molecules. In addition, the nanoparticles were untagged or tagged with nonselective antibodies or antibodies directed against the N-methyl-D-aspartate (NMDA) receptor 1. The nanoparticles containing SOD protected primary neurons in vitro from oxygen-glucose deprivation (OGD) and limited the extent of apoptosis. The nanoparticles showed protection against ischemia and reperfusion injury when applied after injury with a 50% to 60% reduction in infarct volume, reduced inflammatory markers, and improved behavior in vivo. The targeted nanoparticles not only showed enhanced protection but also showed localization to the CA regions of the hippocampus. Nanoparticles alone were not effective in reducing infarct volume. These studies show that targeted nanoparticles containing protective factors may be viable candidates for the treatment of stroke.
Vertical Integration of Pharmacogenetics in Population PK/PD Modeling: A Novel Information Theoretic Method
Authors: Knights J , Chanda P , Sato Y , Kaniwa N , Saito Y , Ueno H , Zhang A , Ramanathan M
Published: February 2013

To critically evaluate an information‐theoretic method for identifying gene–environmental interactions (GEI) associated with pharmacokinetic (PK), pharmacodynamic (PD), and clinical outcomes from genome‐wide pharmacogenetic data. Our approach, which is built on the K‐way interaction information (KWII) metric, was challenged with simulated data and clinical PK/PD data sets from the International Warfarin Pharmacogenetics Consortium (IWPC) and a gemcitabine clinical trial. The KWII efficiently identified both novel and known interactions for warfarin and gemcitabine. Interactions between herbal supplementation and VKORC1 genotype were associated with warfarin response. For gemcitabine‐associated neutropenia, combination treatment with carboplatin and cytidine deaminase (CDA) 208G→A genotypes were identified as risk factors. Gemcitabine disposition was associated with drug metabolism–transporter interactions between deoxycytidine kinase (DCK) and the equilibrative nucleoside transporter (ENT). This novel approach is effective for detecting GEI involved in drug exposure and response and could enable integration of genome‐wide pharmacogenetic data into the population PK/PD analysis paradigm.

CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e25; doi:10.1038/psp.2012.25; advance online publication 6 February 2013
HSP90 inhibitors enhance differentiation and MITF (microphthalmia transcription factor) activity in osteoclast progenitors
Authors: van der Kraan A. Gabrielle J. , Chai Ryan C. C. , Singh Preetinder P. , Lang Benjamin J. , Xu Jiake , Gillespie Matthew T. , Price John T. , Quinn Julian M. W.
Published: February 2013

The HSP90 (heat-shock protein 90) inhibitor 17-AAG (17-allylamino-demethoxygeldanamycin) increases osteoclast formation both in vitro and in vivo, an action that can enhance cancer invasion and growth in the bone microenvironment. The cellular mechanisms through which 17-AAG exerts this action are not understood. Thus we sought to clarify the actions of 17-AAG on osteoclasts and determine whether other HSP90 inhibitors had similar properties. We determined that 17-AAG and the structurally unrelated HSP90 inhibitors CCT018159 and NVP-AUY922 dose-dependently increased RANKL [receptor activator of NF-κB (nuclear factor κB) ligand]-stimulated osteoclastogenesis in mouse bone marrow and pre-osteoclastic RAW264.7 cell cultures. Moreover, 17-AAG also enhanced RANKL- and TNF (tumour necrosis factor)-elicited osteoclastogenesis, but did not affect RANKL-induced osteoclast survival, suggesting that only differentiation mechanisms are targeted. 17-AAG affected the later stages of progenitor maturation (after 3 days of incubation), whereas the osteoclast formation enhancer TGFβ (transforming growth factor β) acted prior to this, suggesting different mechanisms of action. In studies of RANKL-elicited intracellular signalling, 17-AAG treatment did not increase c-Fos or NFAT (nuclear factor of activated T-cells) c1 protein levels nor did 17-AAG increase activity in luciferase-based NF-κB- and NFAT-response assays. In contrast, 17-AAG treatment (and RANKL treatment) increased both MITF (microphthalmia-associated transcription factor) protein levels and MITF-dependent vATPase-d2 (V-type proton ATPase subunit d2) gene promoter activity. These results indicate that HSP90 inhibitors enhance osteoclast differentiation in an NFATc1-independent manner that involves elevated MITF levels and activity.
Plug‐in‐hybrid electric vehicles park as virtual DVR
Authors: Islam F.R. , Pota H.R.
Published: February 2013

Dynamic voltage restorers (DVRs) are utilised in the distribution systems to protect sensitive loads from voltage sags. In this reported work the vehicle to grid technology with a bidirectional converter is used to design a virtual dynamic voltage restorer based on hysteresis voltage control theory. The potential of a low‐cost solution that utilises the mitigation capabilities of plug‐in vehicles parked in charging stations is investigated. Simulations are performed to demonstrate that the proposed virtual DVR improves the power quality while maintaining voltage level at the user end
Temperature‐compensated BAW orientations over 500°C on LGT for frequency control and sensor applications
Authors: Davulis P. , Cunha M. Pereira da
Published: February 2013

Recently extracted langatate (LGT) elastic, piezoelectric and dielectric constants up to 900°C were utilised to predict the temperature coefficient of frequency (TCF) of bulk acoustic wave (BAW) orientations. A range of LGT BAW orientations were identified with turnover temperatures between 100 and 550°C for use in high‐temperature sensor and frequency control applications. In addition, the piezoelectric coupling of the identified orientations was investigated to determine the preferred cuts for high‐temperature operation.
Stress‐induced leakage current in CNT‐MOSFETs using simplified quantitative model
Authors: Ossaimee M.I.
Published: February 2013

The stress‐induced leakage current (SILC) in carbon nanotube (CNT)‐MOSFETs based on a previously developed model for the steady‐state component of SILC across the ultra‐thin gate oxide of a MOS capacitor is calculated. It was found that the contribution of the component due to SILC in the gate current of MOSFETs must not be neglected. It was also found that SILC is larger in the source side than in the drain side.
DC and RF characteristics of In0.52Al0.48As/In0.7Ga0.3As HEMTs at 300 and 16 K
Authors: Endoh A. , Watanabe I. , Mimura T. , Matsui T.
Published: February 2013

Pseudomorphic In0.52Al0.48As/In0.7Ga0.3As HEMTs have been fabricated in the gate length Lg range of 50 to 700 nm and their DC and RF characteristics measured at 300 and 16 K. The maximum drain‐source current Ids, the maximum transconductance gm_max and the cutoff frequency fT values increased at 16 K as expected. The ratios gm_max(16 K)/gm_max(300 K) and fT(16 K)/fT(300 K) decreased with decreasing Lg, which results from the enhancement of the ballistic transport of electrons.
Channel access resistance effects on charge carrier mobility and low-frequency noise in a polymethyl methacrylate passivated SnO2 nanowire field-effect transistors
Authors: Joo Min-Kyu , Huh Junghwan , Mouis Mireille , Park So Jeong , Jeon Dae-Young , Jang Doyoung , Lee Jong-Heun , Kim Gyu-Tae , Ghibaudo Gérard
Published: February 2013

Channel access resistance (Rsd) effects on the charge carrier mobility (μ) and low-frequency noise (LFN) in a polymethyl-methacrylate (PMMA) passivated tin-oxide nanowire (SnO2-NW) field effect-transistor were investigated. To this end, the Y function method was employed for direct electrical parameters extraction without Rsd influence. Numerical simulation was used to evaluate gate-to-channel capacitance (Cgc) accounting for the electrostatic gate coupling effects through PMMA passivation layer. Furthermore, LFN measurements were carried out to study the SnO2/dielectrics interface. The carrier number fluctuation (CNF) noise model was found appropriate to interpret LFN data provided Rsd influence is included.
First principles exploration of NiO and its ions NiO+ and NiO−
Authors: Sakellaris Constantine N. , Mavridis Aristides
Published: February 2013

We present a high level ab initio study of NiO and its ions, NiO+ and NiO−. Employing variational multireference configuration interaction (MRCI) and single reference coupled-cluster methods combined with basis sets of quintuple quality, 54, 20, and 10 bound states of NiO, NiO+, and NiO− have been studied. For all these states, complete potential energy curves have been constructed at the MRCI level of theory; in addition, for the ground states of the three species core subvalence (3s23p6/Ni) and scalar relativistic effects have been taken into account. We report energetics, spectroscopic parameters, dipole moments, and spin-orbit coupling constants. The agreement with experiment is in the case of NiO good, but certain discrepancies that need further investigation have arisen in the case of the anion whose ground state remains computationally a tantalizing matter. The cation is experimentally almost entirely unexplored, therefore, the study of many states shall prove valuable to further investigators. The ground state symmetry, bond distances, and binding energies of NiO and NiO+ are (existing experimental values in parenthesis), X3Σ−(X3Σ−), re = 1.606 (1.62712) Å, D0 = 88.5 (89.2 ± 0.7) kcal/mol, and X4Σ−(?), re = 1.60(?) Å, D0 = 55 (62.4 ± 2.4) kcal/mol, respectively. The ground state of NiO− is 4Σ− (but 2Π experimentally) with D0 = 85–87 (89.2 ± 0.7) kcal/mol.
Non-reciprocity of dipole-exchange spin waves in thin ferromagnetic films
Authors: Kostylev M.
Published: February 2013

The non-reciprocity and asymmetry of the modal profiles for dipole-exchange spin waves have been investigated theoretically. We were interested in the most important case for applications: the waves propagating in in-plane magnetized ferromagnetic films at a right angle to the applied magnetic field. For large-magnetic moment ferromagnetic metallic films with typical thicknesses 10–60 nm which are largely considered promising for magnonic and spintronic applications, the contribution of exchange energy to the total magnetic energy is important; however, their dynamics is most often treated using the exchange-free Damon-Eschbach approach. In this work, we show that although this approach is valid for treatment of wave dispersion, it fails to properly describe such fundamental property of wave excitations as wave modal profiles. Namely we show that the fundamental mode of the dipole-exchange spectrum is localized at the film surface opposite to the surface of localization of the exchange-free Damon-Eshbach surface wave. This “anomalous” localization of the wave does not affect the non-reciprocity of spin wave excitation by microstrip and coplanar transducers but may be detected in other types of experiments.
A new high intensity and short-pulse molecular beam valve
Authors: Yan B. , Claus P. F. H. , van Oorschot B. G. M. , Gerritsen L. , Eppink A. T. J. B. , van de Meerakker S. Y. T. , Parker D. H.
Published: February 2013

In this paper, we report on the design and performance of a new home-built pulsed gas valve, which we refer to as the Nijmegen Pulsed Valve (NPV). The main output characteristics include a short pulse width (as short as 20 μs) combined with operating rates up to 30 Hz. The operation principle of the NPV is based on the Lorentz force created by a pulsed current passing through an aluminum strip located within a magnetic field, which opens the nozzle periodically. The amplitude of displacement of the opening mechanism is sufficient to allow the use of nozzles with up to 1.0 mm diameter. To investigate the performance of the valve, several characterizations were performed with different experimental methods. First, a fast ionization gauge was used to measure the beam intensity of the free jet emanating from the NPV. We compare free jets from the NPV with those from several other pulsed valves in current use in our laboratory. Results showed that a high intensity and short pulse-length beam could be generated by the new valve. Second, the NPV was tested in combination with a skimmer, where resonance enhanced multiphoton ionization combined with velocity map imaging was used to show that the NPV was able to produce a pulsed molecular beam with short pulse duration (∼20 μs using 0.1% NO/He at 6 bars) and low rotational temperature (∼1 K using 0.5% NO/Ar at 6 bars). Third, a novel two-point pump-probe method was employed which we label double delay scan. This method allows a full kinematic characterization of the molecular beam, including accurate speed ratios at different temporal positions. It was found that the speed ratio was maximum (S = 50 using 0.1% NO/He at 3 bars) at the peak position of the molecular beam and decreased when it was on the leading or falling edge.
Investigation on interfacial thermal resistance and phonon scattering at twist boundary of silicon
Authors: Ju Sheng-Hong , Liang Xin-Gang
Published: February 2013

Grain interfaces in nanocrystalline materials play a critical role in thermal transport. A series of twist boundary thermal resistances in silicon is investigated by the nonequilibrium molecular dynamics simulation so as to find the relationship between the boundary resistance, the twist angle, the boundary energy and temperature. The results indicate that the magnitude of the twist grain boundary (GB) thermal resistance is on the order of 10−9 m2 KW−1, and the GB thermal resistance becomes larger with increasing GB energy at most twist angles, and it drops obviously with increasing temperature. The phonon wave packet dynamic simulation shows that the transmission coefficient of the low frequency phonons with long wavelength is close to 100% at the boundary with different twist angles. The transmission coefficient of the longitudinal phonon wave packet decreases with increasing frequency and transverse phonons are produced due to the scattering. In most cases, higher grain boundary energy corresponds to lower transmission coefficient, leading to larger GB thermal resistance.
Calibration of measurement sensitivities of multiple micro-cantilever dynamic modes in atomic force microscopy using a contact detection method
Authors: Liu Zhen , Jeong Younkoo , Menq Chia-Hsiang
Published: February 2013

An accurate experimental method is proposed for on-spot calibration of the measurement sensitivities of multiple micro-cantilever dynamic modes in atomic force microscopy. One of the key techniques devised for this method is a reliable contact detection mechanism that detects the tip-surface contact instantly. At the contact instant, the oscillation amplitude of the tip deflection, converted to that of the deflection signal in laser reading through the measurement sensitivity, exactly equals to the distance between the sample surface and the cantilever base position. Therefore, the proposed method utilizes the recorded oscillation amplitude of the deflection signal and the base position of the cantilever at the contact instant for the measurement sensitivity calibration. Experimental apparatus along with various signal processing and control modules was realized to enable automatic and rapid acquisition of multiple sets of data, with which the calibration of a single dynamic mode could be completed in less than 1 s to suppress the effect of thermal drift and measurement noise. Calibration of the measurement sensitivities of the first and second dynamic modes of three micro-cantilevers having distinct geometries was successfully demonstrated. The dependence of the measurement sensitivity on laser spot location was also experimentally investigated. Finally, an experiment was performed to validate the calibrated measurement sensitivity of the second dynamic mode of a micro-cantilever.
Fabrication of Bi2Te3 nanowire arrays and thermal conductivity measurement by 3ω-scanning thermal microscopy
Authors: Muñoz Rojo M. , Grauby S. , Rampnoux J.-M. , Caballero-Calero O. , Martin-Gonzalez M. , Dilhaire S.
Published: February 2013

Bi2Te3 is well-known for its utility in thermoelectrical applications and more recently as topological insulator. Its nanostructuration has attracted plenty of attention because of its potential capacity to reduce thermal conductivity. Here, we have grown a composite sample made of a Bi2Te3 nanowires (NWs) array embedded in an alumina matrix. We have then performed scanning thermal microscopy (SThM) in a 3ω configuration to measure its equivalent thermal resistance. Using an effective medium model, we could then estimate the mean composite thermal conductivity as well as the thermal conductivity of the NWs to be, respectively, (λC) = (1.68 ± 0.20) W/mK and (λNW) = (1.37 ± 0.20) W/mK, showing a slight thermal conductivity reduction. Up to now, there have been two main techniques reported in literature to evaluate the thermal conductivity of nanostructures: the use of a thermal microchip to probe a single NW once its matrix has been dissolved or the probing of the whole NWs array embedded in a matrix, obtaining the thermal conductivity of the whole as an effective medium. However, the 3ω-SThM presented here is the only technique able to measure the thermal conductivity of single NWs embedded in a matrix as well as the thermal conductivity of the composite locally. This technique is more versatile and straightforward than other methods to obtain the thermal conductivity of nanostructures.
Dimensions, lengths, and separability in finite-dimensional quantum systems
Authors: Chen Lin , Ðoković Dragomir Ž.
Published: February 2013

Many important sets of normalized states in a multipartite quantum system of finite dimension d, such as the set \documentclass[12pt]{minimal}\begin{document}${\cal S}$\end{document}S of all separable states, are real semialgebraic sets. We compute dimensions of many such sets in several low-dimensional systems. By using dimension arguments, we show that there exist separable states which are not convex combinations of d or less pure product states. For instance, such states exist in bipartite M⊗N systems when (M − 2)(N − 2) > 1. This solves an open problem proposed by DiVincenzo, Terhal and Thapliyal about 12 years ago. We prove that there exist a separable state ρ and a pure product state, whose mixture has smaller length than that of ρ. We show that any real \documentclass[12pt]{minimal}\begin{document}$\rho \in {\cal S}$\end{document}ρ∈S, which is invariant under all partial transpose operations, is a convex sum of real pure product states. In the case of the 2⊗N system, the number r of product states can be taken to be \documentclass[12pt]{minimal}\begin{document}$r=\mathop {\rm rank}\rho$\end{document}r= rank ρ. We also show that the general multipartite separability problem can be reduced to the case of real states. Regarding the separability problem, we propose two conjectures describing \documentclass[12pt]{minimal}\begin{document}${\cal S}$\end{document}S as a semialgebraic set, which may eventually lead to an analytic solution in some low-dimensional systems such as 2⊗4, 3⊗3, and 2⊗2⊗2.
Origin of ferromagnetism in Cu-doped SnO2: A first-principles study
Authors: Zhang Kai-Cheng , Liu Yong , Li Yong-Feng , Zhu Yan
Published: February 2013

We investigate the magnetic properties of Cu-doped SnO2, which was reported recently in experiments to possess ferromagnetism at room temperature, by first-principles calculations. Our results show that the doped system prefers the antiferromagnetic state for only Cu substitution. The oxygen vacancies are more inclined to form on the sites nearest to Cu defects. However, only those oxygen vacancies away from Cu defects contribute to the ferromagnetism significantly. Our results reveal that Sn vacancies are much easier to form than oxygen vacancies for their much lower formation energy. Moreover, the Cu-doped system always prefers the ferromagnetic state in the presence of Sn vacancies. Therefore, the origin of ferromagnetism in Cu-doped SnO2 can be attributed to the magnetic mediation of Sn vacancies.
Complementary metal–oxide–semiconductor compatible athermal silicon nitride/titanium dioxide hybrid micro-ring resonators
Authors: Qiu Feng , Spring Andrew M. , Yu Feng , Yokoyama Shiyoshi
Published: February 2013

Micro-ring resonators have been widely utilized in silicon photonics. However they often exhibit a high sensitivity to ambient temperature fluctuations. In this letter, we have demonstrated a complementary metal–oxide–semiconductor compatible athermal micro-ring resonator made from titanium dioxide (TiO2) and silicon nitride (SiNx). We have exploited the negative thermo–optic coefficient of TiO2 to counterbalance the positive coefficient of SiNx. By a precise control over the TiO2 layer thickness, an athermal condition remarkably consistent with the simulation can be achieved. Therefore, a SiNx–TiO2 hybrid micro-ring resonator with a temperature dependent wavelength shift of 0.073 pm/ °C has been realized.
Controlling wave function localization in a multiple quantum well structure
Authors: Bagga Anjana , Venugopalan Anu
Published: February 2013

The dynamics of a wave function describing a particle confined in a multiple quantum well potential is studied numerically. In particular, the case of four wells and six wells has been studied for the first time. As a consequence of quantum mechanical tunneling, an initial wavefunction designed to be localized in one well can localize in the others after a certain time and hop between wells at times which depends on the height and width of the barriers separating the wells. This control over the evolution of the wavefunction with time has direct implications in applications based on carrier dynamics in multiple quantum well nanostructures and can also provide novel mechanisms in solid state quantum computation for information storage and processing. The ability to include any number of wells and control the carrier dynamics in them through easily accessible parameters in our study makes this a particularly attractive system from the point of view of applications.
Stripe-vortex transitions in ultrathin magnetic nanostructures
Authors: Chen J. P. , Wang Z. Q. , Gong J. J. , Qin M. H. , Zeng M. , Gao X. S. , Liu J.-M.
Published: February 2013

In this work, the magnetic states in ultrathin nanostructures are investigated using Monte Carlo simulation, based on a Heisenberg model involving the short-range exchange coupling, long-range dipole-dipole interaction, and perpendicular anisotropy. An intriguing thermally driven magnetic structural transition from perpendicular stripe domain to flux closure (planar vortex) state, accompanied by an apparent thermal hysteresis effect and typical characteristics of the first-order phase transition, is revealed. Furthermore, it is found that the transition can be remarkably modulated by perpendicular anisotropy. The present work suggests a promising approach to manipulate the spin configurations in nanomagnets by adjusting temperature and perpendicular anisotropy.
Communication: Biexciton generation rates in CdSe nanorods are length independent
Authors: Baer Roi , Rabani Eran
Published: February 2013

We study how shape affects multiexciton generation rates in a semiconducting nanocrystal by considering CdSe nanorods with varying diameters and aspect ratios. The calculations employ an atomistic semiempirical pseudopotential model combined with an efficacious stochastic approach applied to systems containing up to 20 000 atoms. The effect of nanorod diameter and aspect ratio on multiexciton generation rates is analyzed in terms of the scaling of the density of trion states and the scaling of the Coulomb couplings. Both show distinct scaling from spherical nanocrystals leading to a surprising result where the multiexciton generation rates are roughly independent of the nanorod length.
Research on the optimization of a novel municipal solid waste shredder
Authors: Luo Siyi , Yang Xianhui , Tao Xiancong , Luo Yin , Fu Jie
Published: February 2013

In this paper, a novel two-inlet municipal solid waste (MSW) shredder was developed to overcome the intermission work of the single-course shredder. The reliability of the two-inlet shredder was investigated and four organic constituents of MSW (plastic, kitchen garbage, leaves, and branch) were shredded in the two-inlet shredder to evaluate the shredder adaptability to MSW complex composition. The results showed that the two-inlet operation mode significantly improved shredding efficiency and reduced energy consumption, compared with single-course shredder. With the two-inlet operation, only approximately 73% of energy (compared with single-course shredder) was used to produce the same amount of products. The shredder was much more effective for the pulverization of soft, ductile, and fibrous materials (kitchen garbage and leaves), but it was not good at pulverization of the brittle material (plastic and branch). A total of 57.7% product of branch was below 10 mm in size, while for kitchen garbage and leaves, the values are 97.7% and 92.5%, respectively. And the value for plastic was the lowest, only 38.0%.
Reactive self-heating model of aluminum spherical nanoparticles
Authors: Martirosyan Karen S , Zyskin M.
Published: February 2013

Aluminum-oxygen reaction is important in highly energetic and high pressure generating systems. Recent experiments with nanostructured thermites suggest that oxidation of aluminum nanoparticles occurs in a few microseconds. Such rapid reaction cannot be explained by a conventional diffusion-based mechanism. We present a rapid oxidation model of a spherical aluminum nanoparticle, using Cabrera-Mott moving boundary mechanism, and taking self-heating into account. In our model, electric potential solves the nonlinear Poisson equation. In contrast with the Coulomb potential, a “double-layer” type solution for the potential and self-heating leads to enhanced oxidation rates. At maximal reaction temperature of 2000 °C, our model predicts overall oxidation time scale in microseconds range, in agreement with the experimental evidence.
Fluorescence quenching due to sliver nanoparticles covered by graphene and hydrogen-terminated graphene
Authors: Huang Cheng-Wen , Lin Hsing-Ying , Huang Chen-Han , Lo Kai-Hong , Chang Yu-Chung , Liu Chih-Yi , Wu Chen-Hao , Tzeng Yonhua , Chui Hsiang-Chen
Published: February 2013

Fluorescence quenching effects on graphene or hydrogen-terminated graphene covered sliver nanoparticles are studied and the results are explained with energy transfer models. The fluorescence signal of R6G is suppressed by the graphene flakes via Förster resonance energy transfer and by the silver nanoparticles via surface energy transfer. The relative fluorescence intensities of R6G are reduced to 28% and 69% on the single-atom-thick graphene flake and the hydrogen-terminated graphene covered silver film, respectively. The mechanism of the quenching effect is illustrated by the energy diagram of electron transition.
Life-history traits of a small-bodied coastal shark
Authors: Gutteridge Adrian N. , Huveneers Charlie , Marshall Lindsay J. , Tibbetts Ian R. , Bennett Mike B.
Published: February 2013

The life histories of small-bodied coastal sharks, particularly carcharhinids, are generally less conservative than those of large-bodied species. The present study investigated the life history of the small-bodied slit-eye shark, Loxodon macrorhinus, from subtropical Hervey Bay, Queensland, and compared this species' biology to that of other coastal carcharhinids. The best-fit age model provided parameters of L∞ = 895 mm total length (TL), k = 0.18 and t0 = –6.3 for females, and L∞ = 832 mm TL, k = 0.44 and t0 = –2.6 for males. For sex-combined data, a logistic function provided the best fit, with L∞ = 842 mm TL, k = 0.41 and α = –2.2. Length and age at which 50% of the population was mature was 680 mm TL and 1.4 years for females, and 733 mm TL and 1.9 years for males. Within Hervey Bay, L. macrorhinus exhibited an annual seasonal reproductive cycle, producing an average litter of 1.9 ± 0.3 s.d. With the exception of the low fecundity and large size at birth relative to maximum maternal TL, the life-history traits of L. macrorhinus are comparable to other small-bodied coastal carcharhinids, and its apparent fast growth and early maturation contrasts that of large-bodied carcharhinids.
Modulation of AgRP-neuronal function by SOCS3 as an initiating event in diet-induced hypothalamic leptin resistance
Authors: Olofsson Louise E. , Unger Elizabeth K. , Cheung Clement C. , Xu Allison W.
Published: February 2013

Significance

Multiple neuronal subtypes are involved in metabolic regulation, but little is known about the temporal dysregulation of neuronal functions upon acute consumption of fat-rich diets. We show that AgRP neurons are the predominant cell type situated outside the blood-brain barrier in the mediobasal hypothalamus. AgRP neurons are able to sense slight changes in plasma metabolic signals, such as leptin, but they also more quickly develop cellular leptin resistance compared with other hypothalamic neurons. We further show that modulation of SOCS3 expression in AgRP neurons plays a dynamic role in metabolic fine tuning in response to acute change of nutritional status.
Specific DNA recognition mediated by a type IV pilin
Authors: Cehovin Ana , Simpson Peter J. , McDowell Melanie A. , Brown Daniel R. , Noschese Rossella , Pallett Mitchell , Brady Jacob , Baldwin Geoffrey S. , Lea Susan M. , Matthews Stephen J. , Pelicic Vladimir
Published: February 2013

Natural transformation is a dominant force in bacterial evolution by promoting horizontal gene transfer. This process may have devastating consequences, such as the spread of antibiotic resistance or the emergence of highly virulent clones. However, uptake and recombination of foreign DNA are most often deleterious to competent species. Therefore, model naturally transformable Gram-negative bacteria, including the human pathogen
Neisseria meningitidis
, have evolved means to preferentially take up homotypic DNA containing short and genus-specific sequence motifs. Despite decades of intense investigations, the DNA uptake sequence receptor in
Neisseria
species has remained elusive. We show here, using a multidisciplinary approach combining biochemistry, molecular genetics, and structural biology, that meningococcal type IV pili bind DNA through the minor pilin ComP via an electropositive stripe that is predicted to be exposed on the filaments surface and that ComP displays an exquisite binding preference for DNA uptake sequence. Our findings illuminate the earliest step in natural transformation, reveal an unconventional mechanism for DNA binding, and suggest that selective DNA uptake is more widespread than previously thought.
Alleviation of chronic pain following rat spinal cord compression injury with multimodal actions of huperzine A
Authors: Yu Dou , Thakor Devang K. , Han Inbo , Ropper Alexander E. , Haragopal Hariprakash , Sidman Richard L. , Zafonte Ross , Schachter Steven C. , Teng Yang D.
Published: February 2013

Significance

Neuropathic pain, one of the most debilitating sequelae of neurotrauma, is an unmet clinical need for at least 40% of patients with spinal cord injury (SCI). We demonstrate that [-]-huperzine A (HUP-A), a naturally occurring
Lycopodium
alkaloid isolated from the Chinese club moss,
Huperzia serrata
, with potent reversible inhibitory action on acetylcholinesterase and
N
-methyl-
D
-aspartate glutamate receptors, offers an exceptional prospect for multimodal treatment of SCI-induced neuropathic pain in rats. HUP-A restores homeostasis of central sensory neurocircuitry without invoking drug tolerance and dependence or respiratory suppression. We therefore conclude that multimodal actions provide a fresh translational approach to reduce chronic pain.
Citrus tristeza virus p23: Determinants for Nucleolar Localization and Their Influence on Suppression of RNA Silencing and Pathogenesis
Authors: Ruiz-Ruiz Susana , Soler Nuria , Sánchez-Navarro Jesús , Fagoaga Carmen , López Carmelo , Navarro Luis , Moreno Pedro , Peña Leandro , Flores Ricardo
Published: February 2013

Citrus tristeza virus (CTV) encodes a singular protein (p23, 209 amino acids) with multiple functions, including RNA silencing suppression (RSS). Confocal laser-scanning microscopy of green fluorescent protein (GFP)-p23 agroexpressed in Nicotiana benthamiana revealed its accumulation in the nucleolus, Cajal bodies, and plasmodesmata. To dissect the nucleolar localization signal (NoLS) typically associated with basic motifs, seven truncated and 10 point-mutated versions of p23 were assayed. Deletion mutants showed that regions 50 to 86 and 100 to 157 (excluding fragment 106 to 114), both with basic motifs and the first with a zinc-finger, contain the (bipartite) NoLS. Alanine substitutions delimited this signal to three cysteines of the Zn-finger and some basic amino acids. RSS activity of p23 in N. benthamiana was abolished by essentially all mutants, indicating that it involves most p23 regions. The necrotic-inducing ability of p23 when launched in N. benthamiana from Potato virus X was only retained by deletion mutant 158-209 and one substitution mutant, showing that the Zn-finger and flanking basic motifs form part of the pathogenic determinant. Ectopic expression of p23 and some deletion mutants in transgenic Mexican lime demarcated a similar determinant, suggesting that p23 affects related pathways in citrus and N. benthamiana. Both RSS activity and pathogenicity of p23 appear related to its nucleolar localization.
Enhanced entrainability of genetic oscillators by period mismatch
Authors: Hasegawa Yoshihiko , Arita Masanori
Published: February 2013

Biological oscillators coordinate individual cellular components so that they function coherently and collectively. They are typically composed of multiple feedback loops, and period mismatch is unavoidable in biological implementations. We investigated the advantageous effect of this period mismatch in terms of a synchronization response to external stimuli. Specifically, we considered two fundamental models of genetic circuits: smooth and relaxation oscillators. Using phase reduction and Floquet multipliers, we numerically analysed their entrainability under different coupling strengths and period ratios. We found that a period mismatch induces better entrainment in both types of oscillator; the enhancement occurs in the vicinity of the bifurcation on their limit cycles. In the smooth oscillator, the optimal period ratio for the enhancement coincides with the experimentally observed ratio, which suggests biological exploitation of the period mismatch. Although the origin of multiple feedback loops is often explained as a passive mechanism to ensure robustness against perturbation, we study the active benefits of the period mismatch, which include increasing the efficiency of the genetic oscillators. Our findings show a qualitatively different perspective for both the inherent advantages of multiple loops and their essentiality.