bluuebunny/crossref_metadata_2025 huggingface dataset:
Blockade of islet amyloid polypeptide fibrillation and cytotoxicity by the secretory chaperones 7B2 and proSAAS
Authors: Peinado Juan R. , Sami Furqan , Rajpurohit Nina , Lindberg Iris
Published: September 2013

The deposition of fibrillated human islet β‐cell peptide islet amyloid polypeptide (hIAPP) into amyloid plaques is characteristic of the pathogenesis of islet cell death during type 2 diabetes. We investigated the effects of the neuroendocrine secretory proteins 7B2 and proSAAS on hIAPP fibrillation in vitro and on cytotoxicity. In vitro, 21‐kDa 7B2 and proSAAS blocked hIAPP fibrillation. Structure–function studies showed that a central region within 21‐kDa 7B2 is important in this effect and revealed the importance of the N‐terminal region of proSAAS. Both chaperones blocked the cytotoxic effects of exogenous hIAPP on Rin5f cells; 7B2 generated by overexpression was also effective. ProSAAS and 7B2 may perform a chaperone role as secretory anti‐aggregants in normal islet cell function and in type 2 diabetes.
Effect of biofeedback cycling training on functional recovery and walking ability of lower extremity in patients with stroke
Authors: Yang Huei‐Ching , Lee Chia‐Ling , Lin Roxane , Hsu Miao‐Ju , Chen Chia‐Hsin , Lin Jau‐Hong , Lo Sing Kai
Published: September 2013

This study aimed to investigate the effectiveness of biofeedback cycling training on lower limb functional recovery, walking endurance, and walking speed for patients with chronic stroke. Thirty‐one patients with stroke (stroke onset >3 months) were randomly assigned into two groups using a crossover design. One group (N = 16; mean: 53.6 ± 10.3 years) underwent conventional rehabilitation and cycling training (30 minutes/time, 5 times per week for 4 weeks), followed by only conventional rehabilitation for another 4 weeks. The other group (N = 15; mean: 54.5 ± 8.0 years) underwent the same training in reverse order. The bike used in this biofeedback cycling training was the MOTOmed viva2 Movement Trainer. Outcome measures included the lower extremity subscale of Fugl‐Meyer assessment (LE‐FMA), the 6‐minute walk test (6MWT), the 10‐meter walk test (10MWT), and the modified Ashworth scale (MAS). All participants were assessed at the beginning of the study, at the end of the 4th week, and at the end of the 8th week. Thirty participants completed the study, including the cycling training interventions and all assessments. The results showed that improvements in the period with cycling training were significantly better than the noncycling period in the LE‐FMA (p < 0.05), 6MWT (p < 0.001), 10MWT (p < 0.001), and MAS (p < 0.001) scores. No significant carryover effects were observed. The improvements on outcome measures were significantly different between the cycling period and the noncycling period after adjusting for potential confounding factors in the multivariate analysis of variance (p < 0.001). The study result indicates that the additional 4‐week biofeedback cycling training could lead to improved LE functional recovery, walking endurance, and speed for patients with chronic stroke.
Intra‐rater Reliability of Ultrasound Imaging of Wrist Extensor Muscles in Patients With Tetraplegia
Authors: Gorgey Ashraf S. , Timmons Mark K. , Michener Lori A. , Ericksen Jeffery J. , Gater David R.
Published: September 2013

Objectives

(i) To determine the intra‐rater reliability and precision of the ultrasound cross‐sectional area (CSA) measurements of the wrist extensors in individuals with spinal cord injury (SCI), and (ii) to determine whether tetraplegia has a negative influence on the reliability and precision for these measurements.

Design

A repeated‐measures cross‐sectional study.

Settings

Clinical hospital and academic settings.

Methods

The study was conducted with 20 men with SCI (9 paraplegia and 11 tetraplegia) and 10 able‐bodied controls. Ultrasound images were captured of the right side extensor carpi radialis‐longus (ECRL) and the extensor digitorum communis (EDC) were captured in 2 sessions separated by 48‐72 hours.

Results

The intraclass correlation coefficients for the CSA measurements of the ECRL and EDC muscles were greater than 0.87 for all 3 groups. The standard error of the measure (SEM) ranged from 0.11‐0.22 cm2 for the ECRL and 0.13‐0.27 cm2 for the EDC. The minimal detectable change of ECL ranged from 0.16 to 0.31 cm2 and of EDC from 0.19 to 0.38 cm2. The group differences in muscle CSA of both muscles were found; these differences were greater than the calculated minimal detectable changes. The intraclass correlation coefficients were lower and the SEMs and minimal detectable changes were higher for the group with tetraplegia compared with the able‐bodied controls and the group with paraplegia.

Conclusions

This study documented substantial intra‐rater reliability of measurements of the ECRL and ECD CSA by using ultrasound images, which support the use of this technique to effectively evaluate the musculoskeletal changes after SCI and during rehabilitation. Skeletal muscle atrophy in persons with tetraplegia might have a negative influence on the reliability and precision of these CSA measurements; however, these differences in reliability and precision are not of clinical significance.
Alaafin Sango, “Oba kò so”: A Historiographical Note with Psychological Perspectives Focusing on Suicide1
Authors: Bakare Muideen Owolabi
Published: September 2013

This note adds a psychological perspective focusing on suicide to the representations of Alaafin Sango in both written and oral literature, and thus explores the dynamics of the images of this widely regarded hero.
Epigenetic consequences of a changing human diet
Authors: Haggarty Paul
Published: September 2013

The human diet has undergone profound changes over recent generations and this trend is likely to accelerate in the 21st century. Innovations in food technology, new ways of producing and processing foods and the increasing use of artificial vitamins and novel ingredients are changing the human diet in ways that our dietary monitoring systems struggle to keep pace with. There is a growing awareness of the importance of diet, but little understanding of how these changes may affect the health of current and future generations. Epigenetic programming, and specifically the persistence of functional epigenetic states following nutritional exposure, is particularly relevant to the issue of dietary change. Epigenetics is emerging as perhaps the most important mechanism through which diet and nutrition can directly influence the genome and there is now considerable evidence for nutritional epigenetic programming of health and the response to diet itself. A number of nutrients and food components that are changing in the human diet have been shown to produce epigenetic states that are stable across different timescales. We need to better understand the nutritional programming of epigenetic states, the persistence of these marks in time and their effect on biological function and the response to diet.
The ‘one-man band’ and entrepreneurial selfhood in neoliberal culture
Authors: Chapman Dale
Published: September 2013

This article proposes that the recent history of the live solo multi-instrumentalist, more conventionally known as the ‘one-man band’, might serve as a useful window onto broader transformations in postmodern culture. If the one-person band has historically been understood as a humorous, culturally devalued phenomenon, with its practitioners occupying marginal race and class positions, the recent visibility of solo multi-instrumentalism in indie and experimental rock attests to its altered status in contemporary culture. The present discussion situates the shifting fortunes of the one-person band in relation to the contemporary hegemony of neoliberal conceptions of subjectivity. In their performance of nimble, flexible and omni-competent self-reliance, artists such as Theresa Andersson, Robert Fripp and Andrew Bird model some of the key qualities idealised by theorists of a free-market ‘entrepreneurial selfhood’.
Full NP Object Shift: The Old Norse Puzzle and the Faroese Puzzle revisited
Authors: Thráinsson Höskuldur
Published: September 2013

This paper argues that there is no reason to believe that full NP Object Shift (NPOS) was not found in Old Norse (Old Icelandic) nor that it is more common in Modern Icelandic than in earlier stages of the language. In addition, it is claimed that NPOS is also an option in Modern Faroese, contrary to common belief, although it is much more restricted in Faroese than in Icelandic. These results demonstrate the usefulness of systematic corpus studies while at the same time reminding us of their limits. In addition, they shed a new light on the status of Faroese among the Scandinavian languages and on the nature of intra-speaker variation and grammar competition.
VP anaphors and Object Shift: What do VP anaphors reveal about the licensing conditions for Object Shift in Danish?
Authors: Ørsnes Bjarne
Published: September 2013

The article discusses the placement of the VP anaphor det ‘it’ as a complement of verbs selecting VP complements in Danish. With verbs that only allow a VP complement, the VP anaphor must be in SpecCP regardless of its information structure properties. If SpecCP is occupied by an operator, the anaphor can be in situ, but it cannot shift. With verbs that allow its VP complement to alternate with an NP complement, the VP anaphor can be in SpecCP, shifted or in situ according to the information structural properties of the anaphor. Only if SpecCP is occupied by an operator, must a topical anaphor be in situ. The article argues that a shifted pronominal in Danish must be categorially licensed by the verb and extends this analysis to shifting locatives. An Optimality Theory analysis is proposed that accounts for the observed facts.
Risk factors for sporadic domestically acquired Salmonella serovar Enteritidis infections: a case-control study in Ontario, Canada, 2011
Authors: MIDDLETON D. , SAVAGE R. , TIGHE M. K. , VRBOVA L. , WALTON R. , WHITFIELD Y. , VARGA C. , LEE B. , ROSELLA L. , DHAR B. , JOHNSON C. , AHMED R. , ALLEN V. G. , CROWCROFT N. S.
Published: September 2013

In Ontario, Canada, the number of Salmonella Enteritidis (SE) cases increased over the years 2005–2010. A population-based case-control study was undertaken from January to August 2011 for the purpose of identifying risk factors for acquiring illness due to SE within Ontario. A total of 199 cases and 241 controls were enrolled. After adjustment for confounders, consuming any poultry meat [adjusted odds ratio (aOR) 2·24, 95% confidence interval (CI) 1·31–3·83], processed chicken (aOR 3·32, 95% CI 1·26–8·76) and not washing hands following handling of raw eggs (OR 2·82, 95% CI 1·48–5·37) were significantly associated with SE infection. The population attributable fraction was 46% for any poultry meat consumption and 10% for processed chicken. Poultry meat continues to be identified as a risk factor for SE illness. Control of SE at source, as well as proper food handling practices, are required to reduce the number of SE cases.
Precursors of adolescent substance use from early childhood and early adolescence: Testing a developmental cascade model
Authors: Sitnick Stephanie L. , Shaw Daniel S. , Hyde Luke W.
Published: September 2013

This study examined developmentally salient risk and protective factors of adolescent substance use assessed during early childhood and early adolescence using a sample of 310 low-income boys. Child problem behavior and proximal family risk and protective factors (i.e., parenting and maternal depression) during early childhood, as well as child and family factors and peer deviant behavior during adolescence, were explored as potential precursors to later substance use during adolescence using structural equation modeling. Results revealed that early childhood risk and protective factors (i.e., child externalizing problems, mothers' depressive symptomatology, and nurturant parenting) were indirectly related to substance use at the age of 17 via risk and protective factors during early and middle adolescence (i.e., parental knowledge and externalizing problems). The implications of these findings for early prevention and intervention are discussed.
‘A grudge among the people’: Commercial Conflict, Conspiracy, Petitioning and Poaching in Cranbrook, 1594–1606
Authors: HIPKIN STEPHEN , PITTMAN SUSAN
Published: September 2013

During the later sixteenth century, increasing competition for wood fuel supplies led to rising tension between Wealden cloth manufacturers and ironmasters and to a prolonged but unsuccessful campaign by clothiers seeking parliamentary legislation that would radically curtail iron production in the Cranbrook area. Remarkably revealing files among the papers of Sir John Leveson, one of Kent's late Elizabethan deputy lieutenants, show that during the winter of 1594–5, Cranbrook's frustrated clothiers and their allies among other chief inhabitants of the parish attempted to hijack plebeian distress over low wages and high food and fuel prices for their own ends. It is unlikely that those devising or encouraging industrial sabotage that winter included Cranbrook's richer clothiers, but they were certainly behind plans to mobilise a mass petition to the crown for the suppression of ironworks. In turn, two of Cranbrook's parish officials, deftly exploiting fears of a disorderly march on London, managed to persuade Sir John Leveson to lobby the privy councillor Lord Cobham on the clothiers’ behalf, although to no avail. Thereafter, Cranbrook clothiers vented their frustration against the Bakers of Sissinghurst, who owned the local iron forge and furnace, by frequently raiding the family's deer park, sometimes in conjunction with local gentry pursuing their passion for unlawful hunting.
Farmwives, Domesticity and Work in Late Nineteenth-Century Ireland
Authors: BARCLAY KATIE
Published: September 2013

Despite the growing significance of the ideology of domesticity and changing farming practices, late nineteenth and early twentieth-century Irish farmwives continued to have an active economic role on the farm. The continuation of their economic role reflected wider cultural beliefs that saw work as central to claims to property ownership, reinforced by the growth in the language of economic and political rights during the nineteenth century, which shaped how men and women understood work, ownership and personal rights.
Clothing the Landscape: Change and the Rural Vision in the Work of Thomas Hardy (1840–1928)
Authors: WORTH RACHEL
Published: September 2013

This article considers the ways in which clothing is represented in selected work of Thomas Hardy in the context of wider social and economic change in nineteenth-century English rural society. While taking into account the difficulties of using fictional literature in this way, I suggest that it is precisely Hardy's subjectivity that makes his observations so compelling and that his perception of change lies at the heart of his representation of dress. I endeavour to show how in his writing, the perceived tension between an unchanging, idealised, countryside increasingly subjected to the influence of an urban culture is frequently expressed, either directly or metaphorically, in terms of clothing. The social and economic changes, including agricultural change, of which Hardy was so acutely aware, help to account for the disappearance of traditional features of rural dress, such as the smock-frock and the sun-bonnet. In their place were adopted styles influenced by notions of ‘fashion’ and made available through the process of mass production which Hardy associated primarily with towns. For Hardy, the influence of urban fashions alienated people from that individuality and speciality in dress which formed a link with their environment and ultimately their own past and history.
Use of oral budesonide in the management of protein-losing enteropathy due to restrictive cardiomyopathy
Authors: Gursu Hazım A. , Varan Birgul , Erdogan Ilkay
Published: September 2013

A 7-year-old male patient who had abdominal swelling and eyelid oedema was diagnosed with restrictive cardiomyopathy. His serum albumin level was 2.3 g/dl. Protein-losing enteropathy due to restrictive cardiomyopathy was diagnosed and oral budesonide was started. His serum albumin level began to rise and ascites and peripheric oedema disappeared. The patient underwent a successful cardiac transplantation and budesonide was stopped. After the heart transplantation, the albumin level decreased to 2.3 g/dl, and therefore it was restarted. When the serum albumin level increased, the budesonide dose was tapered and stopped in 1 month. Budesonide may be an effective drug in patients with protein-losing enteropathy due to heart failure.
The joy of sex pheromones
Authors: Gomez‐Diaz Carolina , Benton Richard
Published: September 2013

Sex pheromones provide an important means of communication to unite individuals for successful reproduction. Although sex pheromones are highly diverse across animals, these signals fulfil common fundamental roles in enabling identification of a mating partner of the opposite sex, the appropriate species and of optimal fecundity. In this review, we synthesize both classic and recent investigations on sex pheromones in a range of species, spanning nematode worms, insects and mammals. These studies reveal comparable strategies in how these chemical signals are produced, detected and processed in the brain to regulate sexual behaviours. Elucidation of sex pheromone communication mechanisms both defines outstanding models to understand the molecular and neuronal basis of chemosensory behaviours, and reveals how similar evolutionary selection pressures yield convergent solutions in distinct animal nervous systems.EMBO reports advance online publication 13 September 2013; doi:10.1038/embor.2013.140
Brothers in arms
Authors: Rinaldi Andrea
Published: September 2013

The horrific injuries and difficult working conditions faced by military medical personnel have forced the military to fund biomedical research to treat soldiers; those new technologies and techniques contribute significantly to civilian medicine.
Time-calibrated Milankovitch cycles for the late Permian
Authors: Wu Huaichun , Zhang Shihong , Hinnov Linda A. , Jiang Ganqing , Feng Qinglai , Li Haiyan , Yang Tianshui
Published: September 2013

An important innovation in the geosciences is the astronomical time scale. The astronomical time scale is based on the Milankovitch-forced stratigraphy that has been calibrated to astronomical models of paleoclimate forcing; it is defined for much of Cenozoic–Mesozoic. For the Palaeozoic era, however, astronomical forcing has not been widely explored because of lack of high-precision geochronology or astronomical modelling. Here we report Milankovitch cycles from late Permian (Lopingian) strata at Meishan and Shangsi, South China, time calibrated by recent high-precision U–Pb dating. The evidence extends empirical knowledge of Earth’s astronomical parameters before 250 million years ago. Observed obliquity and precession terms support a 22-h length-of-day. The reconstructed astronomical time scale indicates a 7.793-million year duration for the Lopingian epoch, when strong 405-kyr cycles constrain astronomical modelling. This is the first significant advance in defining the Palaeozoic astronomical time scale, anchored to absolute time, bridging the Palaeozoic–Mesozoic transition.
The ubiquitin–proteasome system regulates the stability and activity of the glucose sensor glucokinase in pancreatic β-cells
Authors: Hofmeister-Brix Anke , Lenzen Sigurd , Baltrusch Simone
Published: September 2013

The ubiquitin–proteasome system is important to maintain pancreatic β-cell function. Inhibition of the proteasome significantly reduced glucose-induced insulin secretion. Key regulators of the stimulus/secretion cascade seem to be affected by protein misfolding if the proteasome is down-regulated as recently reported in humans with Type 2 diabetes. It remains unknown, however, whether the glucose sensor enzyme glucokinase is involved in this process. A direct interaction between glucokinase and ubiquitin could be shown in vivo by FRET, suggesting regulation of glucokinase by the proteasome. After proteasome inhibition glucokinase activity was significantly reduced in MIN6 cells, whereas the protein content was increased, indicating protein misfolding. Enhancing the availability of chaperones by cyclohexamide could induce refolding and restored glucokinase activity. Glucokinase aggregation due to proteasome blocking with MG132, bortezomib, epoxomicin or lactacystin could be detected in MIN6 cells, primary β-cells and hepatocytes using fluorescence-based assays. Glucokinase aggresome formation proceeded microtubule-assisted and was avoided by cyclohexamide. Thus the results of the present study provide support for glucokinase misfolding and aggregation in case of a diminished capacity of the ubiquitin–proteasome system in pancreatic β-cells. In the Type 2 diabetic situation this could contribute to reduced glucose-induced insulin secretion.
Structures and target recognition modes of PDZ domains: recurring themes and emerging pictures
Authors: Ye Fei , Zhang Mingjie
Published: September 2013

PDZ domains are highly abundant protein–protein interaction modules and are often found in multidomain scaffold proteins. PDZ-domain-containing scaffold proteins regulate multiple biological processes, including trafficking and clustering receptors and ion channels at defined membrane regions, organizing and targeting signalling complexes at specific cellular compartments, interfacing cytoskeletal structures with membranes, and maintaining various cellular structures. PDZ domains, each with ~90-amino-acid residues folding into a highly similar structure, are best known to bind to short C-terminal tail peptides of their target proteins. A series of recent studies have revealed that, in addition to the canonical target-binding mode, many PDZ–target interactions involve amino acid residues beyond the regular PDZ domain fold, which we refer to as extensions. Such extension sequences often form an integral structural and functional unit with the attached PDZ domain, which is defined as a PDZ supramodule. Correspondingly, PDZ-domain-binding sequences from target proteins are frequently found to require extension sequences beyond canonical short C-terminal tail peptides. Formation of PDZ supramodules not only affords necessary binding specificities and affinities demanded by physiological functions of PDZ domain targets, but also provides regulatory switches to be built in the PDZ–target interactions. At the 20th anniversary of the discovery of PDZ domain proteins, we try to summarize structural features and target-binding properties of such PDZ supramodules emerging from studies in recent years.
New roles for old pathways? A circuitous relationship between reactive oxygen species and cyclo-oxygenase in hypertension
Authors: Hernanz Raquel , Briones Ana M. , Salaices Mercedes , Alonso María J.
Published: September 2013

Elevated production of prostanoids from the constitutive (COX-1) or inducible (COX-2) cyclo-oxygenases has been involved in the alterations in vascular function, structure and mechanical properties observed in cardiovascular diseases, including hypertension. In addition, it is well known that production of ROS (reactive oxygen species) plays an important role in the impaired contractile and vasodilator responses, vascular remodelling and altered vascular mechanics of hypertension. Of particular interest is the cross-talk between NADPH oxidase and mitochondria, the main ROS sources in hypertension, which may represent a vicious feed-forward cycle of ROS production. In recent years, there is experimental evidence showing a relationship between ROS and COX-derived products. Thus ROS can activate COX and the COX/PG (prostaglandin) synthase pathways can induce ROS production through effects on different ROS generating enzymes. Additionally, recent evidence suggests that the COX–ROS axis might constitute a vicious circle of self-perpetuating vasoactive products that have a pathophysiological role in altered vascular contractile and dilator responses and hypertension development. The present review discusses the current knowledge on the role of oxidative stress and COX-derived prostanoids in the vascular alterations observed in hypertension, highlighting new findings indicating that these two pathways act in concert to induce vascular dysfunction.
Subaxial Cervical Spine Trauma: Evaluation and Surgical Decision-Making
Authors: Joaquim Andrei F. , Patel Alpesh A.
Published: September 2013

Study Design

Literature review.

Objective

To discuss the evaluation and management of subaxial cervical spine trauma (C3–7).

Methods

A literature review of the main imaging modalities, classification systems, and nonsurgical and surgical treatment performed.

Results

Computed tomography and reconstructions allow for accurate radiologic identification of subaxial cervical spine trauma in most cases. Magnetic resonance imaging can be utilized to evaluate the stabilizing discoligamentous complex, the nerves, and the spinal cord. The Subaxial Injury Classification (SLIC) is a new system that aids in injury classification and helps guide the decision-making process of conservative versus surgical treatment. Though promising, the SLIC system requires further validation. When the decision for surgical treatment is made, early decompression (less than 24 hours) has been associated with better neurologic recovery. Surgical treatment should be individualized based on the injury characteristics and surgeon's preferences.

Conclusions

The current state of subaxial cervical spine trauma is one of great progress. However, many questions remain unanswered. We need to continue to account for the individual patient, surgeon, and hospital circumstances that effect decision making and care.
Micellization model for the polymerization of clathrin baskets
Authors: Muthukumar M. , Nossal Ralph
Published: September 2013

A thermodynamic model is used to investigate the conditions under which clathrin triskelions form polyhedral baskets. The analysis, which is similar to classical methods used to study micelle formation, relates clathrin basket energetics to system parameters linked to triskelial rigidity, the natural curvature of an isolated triskelion, and interactions between triskelial legs in the assembled polyhedra. Mathematical theory predicts that a minimal (“critical”) clathrin concentration, CC, needs to be surpassed in order for basket polymerization to occur, and indicates how CC, and the amount of polymerized material, depend on the chosen parameters. Analytical expressions are obtained to indicate how changes in the parameters affect the sizes of the polyhedra which arise when the total clathrin concentration exceeds CC. A continuum analytic approximation then is used to produce numerical results that illustrate the derived dependences.
Extension of many-body theory and approximate density functionals to fractional charges and fractional spins
Authors: Yang Weitao , Mori-Sánchez Paula , Cohen Aron J.
Published: September 2013

The exact conditions for density functionals and density matrix functionals in terms of fractional charges and fractional spins are known, and their violation in commonly used functionals has been shown to be the root of many major failures in practical applications. However, approximate functionals are designed for physical systems with integer charges and spins, not in terms of the fractional variables. Here we develop a general framework for extending approximate density functionals and many-electron theory to fractional-charge and fractional-spin systems. Our development allows for the fractional extension of any approximate theory that is a functional of G0, the one-electron Green's function of the non-interacting reference system. The extension to fractional charge and fractional spin systems is based on the ensemble average of the basic variable, G0. We demonstrate the fractional extension for the following theories: (1) any explicit functional of the one-electron density, such as the local density approximation and generalized gradient approximations; (2) any explicit functional of the one-electron density matrix of the non-interacting reference system, such as the exact exchange functional (or Hartree-Fock theory) and hybrid functionals; (3) many-body perturbation theory; and (4) random-phase approximations. A general rule for such an extension has also been derived through scaling the orbitals and should be useful for functionals where the link to the Green's function is not obvious. The development thus enables the examination of approximate theories against known exact conditions on the fractional variables and the analysis of their failures in chemical and physical applications in terms of violations of exact conditions of the energy functionals. The present work should facilitate the calculation of chemical potentials and fundamental bandgaps with approximate functionals and many-electron theories through the energy derivatives with respect to the fractional charge. It should play an important role in developing accurate approximate density functionals and many-body theory.
Structural modification and twinning stress reduction in a high-temperature Ni-Mn-Ga magnetic shape memory alloy
Authors: Pagounis E. , Chulist R. , Lippmann T. , Laufenberg M. , Skrotzki W.
Published: September 2013

Mechanical and synchrotron diffraction experiments were performed to investigate the temperature dependent structural changes in a Ni-Mn-Ga single crystal. The initial sample exhibits a mixture of seven-layered (7M) and non-modulated (NM) martensites at room temperature. Compression along ⟨100⟩ resulted in a strain of 18%, indicating a stress-induced intermartensitic transformation from the 7M to the NM phase. The thermally induced intermartensitic transformation follows the sequence 5M→7M→NM during cooling from the austenite phase. The structural changes are quantitatively reflected in the mechanical response. A twinning stress of 3.8 MPa is measured at 90 °C, which is the lowest reported in high-temperature Ni-Mn-Ga structures.
Rigidity in the positive mass theorem with charge
Authors: Khuri Marcus A. , Weinstein Gilbert
Published: September 2013

In this paper, we show how a natural coupling of the Dirac equation with the generalized Jang equation leads to a proof of the rigidity statement in the positive mass theorem with charge, without the maximal slicing condition, provided a solution to the coupled system exists.
Very-large-scale coherent structures in the wall pressure field beneath a supersonic turbulent boundary layer
Authors: Beresh Steven J. , Henfling John F. , Spillers Russell W. , Pruett Brian O. M.
Published: September 2013

Data have been acquired from a spanwise array of fluctuating wall pressure sensors beneath a wind tunnel wall boundary layer at Mach 2, then invoking Taylor's hypothesis allows the temporal signals to be converted into a spatial map of the wall pressure field. Different frequency ranges of pressure fluctuations may be accessed by bandpass filtering the signals. In all frequency ranges, this reveals signatures of coherent structures where negative pressure events are interspersed amongst positive events, with some degree of alternation in the streamwise direction. Within lower frequency ranges, streaks of instantaneously correlated pressure fluctuations elongated in the streamwise direction exhibit a spanwise meander and show apparent merging of pressure events. Coherent length scales based on single-sensor correlations are artificially shortened by neglecting this meander and merging, but are captured correctly using the sensor array. These measurements are consistent with similar observations by other researchers in the velocity field above the wall, and explain the presence of the flat portion of the wall pressure spectrum at frequencies well below those associated with the boundary layer thickness. However, the pressure data lack the common spanwise alternation of positive and negative events found in velocity data, and conversely demonstrate a weak positive correlation in the spanwise direction at low frequencies.
Piezoelectric manipulation of Co/CoO exchange-bias bilayer system at low-temperature
Authors: Rizwan Syed , Ali S. I. , Zhang Q. T. , Zhang S. , Zhao Y. G. , Anis-ur-Rehman M. , Tufail Muhammad , Han X. F.
Published: September 2013

The spintronics devices based on electric field is a key challenge today and the exchange bias effect is the basic structure used in these devices. We have studied the electric field control of annealed Co/CoO exchange bias system fabricated on the (011)-Pb(Mg1∕3Nb2∕3)O3-PbTiO3 piezoelectric substrate. The Co/CoO heterostructure was cooled down from above the Neel temperature (TN = 291 K) down to 15 K in the presence of electric and magnetic fields; the sample was cooled every time for each electric field measurement in order to avoid the training effect. The exchange bias effect was found to increase by 44% at the highest electric field value of 8 kV/cm measured at 15 K. The electric field tuning of exchange bias is attributed to the different magnetization reversal processes for left and right branches of magnetic hysteresis loop. Our results reinforce the possibility for the use of electric field as a tool to control the future spintronics devices.
On applicability of the “thermalized potential” solver in simulations of the plasma flow in Hall thrusters
Authors: Geng Jinyue , Brieda Lubos , Rose Laura , Keidar Michael
Published: September 2013

In Hall thrusters, the potential distribution plays an important role in discharge processes and ion acceleration. This paper presents a 2D potential solver in the Hall thruster instead of the “thermalized potential”, and compares equipotential contours solved by these two methods for different magnetic field conditions. The comparison results reveal that the expected “thermalized potential” works very well when the magnetic field is nearly uniform and electron temperature is constant along the magnetic field lines. However for the case with a highly non-uniform magnetic field or variable electron temperature along the magnetic field lines, the “thermalized potential” is not accurate. In some case with magnetic separatrix inside the thruster channel, the “thermalized potential” model cannot be applied at all. In those cases, a full 2D potential solver must be applied. Overall, this paper shows the limit of applicability of the “thermalized potential” model.
Finite size effects in the crystallization of a bulk metallic glass
Authors: Gopinadhan Manesh , Shao Zhen , Liu Yanhui , Mukherjee Sundeep , Sekol Ryan C. , Kumar Golden , Taylor André D. , Schroers Jan , Osuji Chinedum O.
Published: September 2013

We explore finite size effects in the crystallization of a bulk metallic glass with nm-scale dimensions. Nanorods of Pt57.5Cu14.7Ni5.3P22.5 are produced by thermoplastic extrusion of supercooled liquid through a nanoporous template. The nanorods exhibit remarkable differences in their crystallization behavior above the glass transition. Crystallization for 100 and 200 nm diameter nanorods occurred at 6 and 24 °C lower, respectively, than the nominal crystallization temperature for bulk material while the glass transition temperatures were unchanged from the bulk value. Size dependent crystallization kinetics is discussed within a framework of classical nucleation theory, as well as possible shear and surface-induced effects.
Contactless measurement of electrical parameters and estimation of current-voltage characteristics of Si solar cells using the illumination intensity dependence of lock-in carrierography (photoluminescence) images
Authors: Liu Junyan , Melnikov Alexander , Mandelis Andreas
Published: September 2013

A combined theoretical and experimental approach is reported using spectrally windowed lock-in carrierography imaging (lock-in photoluminescence) under variable illumination intensity to provide quantitative contactless measurements of key electrical parameters (photogenerated current density, Jg, open circuit voltage, VOC, and maximum power voltage, Vm) of multicrystalline silicon (m-Si) solar cells in very good agreement with standard electrical measurements. The method is based on a recently developed photocarrier radiative recombination current flux relation which links the optical and electrical characteristics of solar cells. In addition, this approach is shown to yield non-contact all-optical estimates of the solar-cell current-voltage characteristics with the conventional variable load resistance replaced by variable laser intensity.
Hot spot engineering for light absorption enhancement of solar cells with a super-structured transparent conducting electrode
Authors: Smaali R. , Centeno E. , Moreau A.
Published: September 2013

We study the impact of a super-structuration of the transparent conducting electrode made of polycrystalline ZnO:Al on the efficiency of thin solar cells based on amorphous silicon. We demonstrate that photonic crystal cavities etched in the electrode present efficient anti-reflective properties and add absorption resonances in the red part of the spectrum where other structures are inefficient. This super-structuring boosts the optical absorption by 4.2% and broaden the angular acceptance compared to conventional grating patterns. The origin of these cavity states is explained in the framework of the envelop function approach.
Nanometric particle size and phase controlled synthesis and characterization of γ-Fe2O3 or (α + γ)-Fe2O3 by a modified sol-gel method
Authors: Silva Marcela F. , de Oliveira Luiz A. S. , Ciciliati Mariani A. , Silva Lais T. , Pereira Bruna S. , Hechenleitner Ana Adelina W. , Oliveira Daniela M. F. , Pirota Kleber R. , Ivashita Flávio F. , Paesano Andrea , Martin Pastor J. , Iñaki Pérez-Landazábal J. , Pineda Edgardo A. G.
Published: September 2013

Fe2O3 nanoparticles with sizes ranging from 15 to 53 nm were synthesized by a modified sol-gel method. Maghemite particles as well as particles with admixture of maghemite and hematite were obtained and characterized by XRD, FTIR, UV-Vis photoacoustic and Mössbauer spectroscopy, TEM, and magnetic measurements. The size and hematite/maghemite ratio of the nanoparticles were controlled by changing the Fe:PVA (poly (vinyl alcohol)) monomeric unit ratio used in the medium reaction (1:6, 1:12, 1:18, and 1:24). The average size of the nanoparticles decreases, and the maghemite content increases with increasing PVA amount until 1:18 ratio. The maghemite and hematite nanoparticles showed cubic and hexagonal morphology, respectively. Direct band gap energy were 1.77 and 1.91 eV for A6 and A18 samples. Zero-field-cooling–field-cooling curves show that samples present superparamagnetic behavior. Maghemite-hematite phase transition and hematite Néel transition were observed near 700 K and 1015 K, respectively. Magnetization of the particles increases consistently with the increase in the amount of PVA used in the synthesis. Mössbauer spectra were adjusted with a hematite sextet and maghemite distribution for A6, A12, and A24 and with maghemite distribution for A18, in agreement with XRD results.
The reflectivity of carbon fiber reinforced polymer short circuit illuminated by guided microwaves
Authors: Bojovschi A. , Scott J. , Ghorbani K.
Published: September 2013

An investigation of the interaction between guided electromagnetic waves and carbon fibre reinforced polymer waveguide short circuits is presented. To determine the electromagnetic response of the composite waveguide short circuit, its anisotropic characteristics are considered. The reflection coefficients of the short circuit, at the reference plane, are about 0.98 over the whole 8 GHz to 12 GHz band. The results indicate the viability of carbon fiber based short circuits for lightweight waveguides.
Correlation between intrinsic defects and electrical properties in the high-quality Cu2ZnSnS4 single crystal
Authors: Nagaoka Akira , Miyake Hideto , Taniyama Tomoyasu , Kakimoto Koichi , Yoshino Kenji
Published: September 2013

Temperature dependent Hall effect measurements from 20 to 300 K have been performed on the quaternary compounds Cu2ZnSnS4 (CZTS) single crystals. The conductivity mechanisms can be described by a two-path system using Mott variable range hopping and typical thermal activation conduction. The center level of the acceptor band is 132 meV above the valence band maximum and is of width 40 meV. A correlation between the activation energy and acceptor concentration in CZTS is observed.
Anaerobic mono- and co-digestion of maize silage and low solid swine wastewater in a novel two-state (liquid/solid) anaerobic digester
Authors: Markou Giorgos , Georgakakis Dimitris
Published: September 2013

In this study, maize silage was anaerobically mono- and co-digested together with low solid swine wastewater in a novel two-state (liquid/solid) anaerobic digester. The special subject of the two-state digester is that operates with both, liquid and solid fractions, which are present in a segregated form inside the digester. The feeding and the withdrawal of the liquid and the solid fraction can be performed independently to allow different retention times for each fraction. In this study, as solid substrate, maize silage was used, which was nested in a plastic mesh in order to be kept inside the digester in a segregated solid state against the liquid state. As liquid substrate, low solid swine wastewater was used. In general, it was easy to remove separately and independently the two solid and liquid fractions. Two types of digesters were used: one batch type (BT) digester, in which maize silage was mono-digested as sole substrate and a combined type (CT) digester, in which maize silage was fed batch and the low solid swine wastewater was fed semi-continuously (every 48 h). Average biomethane yield at organic load rate of 1 kg VS/mR3-48 h amounted to 0.477 Nm3/kg VS for the BT and to 0.334 Nm3/kg VS for the CT digesters.
Sensitivity analysis of solar photovoltaic modules to environmental factors through new definitions and formulas
Authors: Ziar Hesan , Karegar Hossein Kazemi
Published: September 2013

Photovoltaic panels are very sensitive to environmental conditions. Study and formulation of this sensitivity lead to improvement of photovoltaic systems. Parameter which shows the rate of impact of environmental conditions on photovoltaic panels is Fill Factor (FF). In this paper, sensitivity of Fill Factor to environmental conditions is compared with another defined parameter, Secondary Efficiency. This comparison has been performed by parallel analyzing of temperature and irradiation, and also the effect of irradiation on temperature. Results of this comparison lead to define another parameter, Influence of Environmental Factors, using binary coding method. Binary coding method studies Fill Factor at all possible shading conditions in an array through MATLAB software. Experimental task has been accomplished to verify the simulation results. Obtained results illustrate that best working condition for a solar module occurs approximately at half sun and an array will be more vulnerable to environmental factors by increasing the number of modules.
Influence of local curvature on sputtering
Authors: Nietiadi Maureen L. , Urbassek Herbert M.
Published: September 2013

Sputtering depends on the local surface curvature; it is higher for convex and lower for concave surfaces than for a flat reference target. We analyze this dependence theoretically and show that the sputter yield primarily depends on a dimension-free curvature parameter, and second on the relative variance of the deposited-energy distribution in the direction along the ion beam. Using molecular dynamics, we study the effects in an exemplary way for 500 eV Ar impact on an a-Si target; here, we compare a wire and a valley structure (radii of curvature 2.5 nm) with a planar target. Our findings demonstrate that the sputter yield, the crater function, and the angular distribution of sputtered particles strongly depend on the curvature.
Remote phonon and impurity screening effect of substrate and gate dielectric on electron dynamics in single layer MoS2
Authors: Zeng Lang , Xin Zheng , Chen Shaowen , Du Gang , Kang Jinfeng , Liu Xiaoyan
Published: September 2013

The effect of both remote phonon originating from and the screening of extrinsic charged impurity by substrate and gate dielectric on the electron dynamics of single layer MoS2 are investigated with Monte Carlo method. The temperature-dependent mobility curve measured by Hall effect is reproduced by taking the two counter roles played by substrate and gate dielectric into consideration. Based on the analysis of remote phonon effect and charged impurity screening, an optimized transistor structure which is composed of single HfO2 gate dielectric with interfacial layer and absence of SiO2 substrate is proposed for the realization of mobility approaching intrinsic value and best device performance.
Issues to improve ground source heat pump units in Korea: Refrigerant application and hot water generation
Authors: Aikins Kojo Atta , Choi Jong Min
Published: September 2013

There is a need for hot water generation in a more efficient and environmentally friendly way for heating, ventilating, and air conditioning systems, and the heat pump is a great candidate for that. In this paper, hot water temperatures generated by ground source heat pump (GSHP) systems in Korea are analysed. It is also important to minimize the use and emission of refrigerants with high global warming potential (GWP) and ozone depletion potential (ODP) to reduce their impact on the environment. In this regard, refrigerants that are used in GSHP units in Korea are investigated. The database is composed of 86 GSHP units certified in Korea according to governmental regulation. The GSHP units are divided into three types: water-to-water, water-to-air, and water-to-air multi heat pump units. The average hot water temperature generated by the certified GSHP units is 43.8 °C with the Korean standard test conditions (NR GT 101). Temperature difference 3.8 °C between inlet and outlet of condenser is less than 5 °C as presented by the European Standard (NF EN standard). In order to replace the boiler and the conventional air conditioning unit with a highly efficient GSHP system, there is the need to increase the hot water generation temperature. With the refrigerants, 53.8% of the 78 water-to-water GSHP units use the hydro chlorofluorocarbon (HCFC) refrigerant, R22, while the others use the hydrofluorocarbon (HFC) refrigerants, R410A, R407C, and R134a. All water-to-air and water-to-air multi heat pump units use R410A refrigerant. Because R22 is a HCFC and has high GWP and ODP, it is being replaced with HFC and natural refrigerants. However, HFC refrigerants also have high GWP. It is therefore recommended to encourage the responsible use or replacement of HFC refrigerants with natural and other alternative refrigerants in Korea.