bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of growth rates under the constraint of growth‐development trade‐off in a fish
Authors: Fujimoto Shingo , Kawajiri Maiko , Suzuki Yuya , Yamahira Kazunori
Published: November 2011

Intrinsic growth rates often vary greatly among populations within a single species, implying that trade‐offs with fast growth are present. It has been hypothesized that such a trade‐off exists between growth rate and development rate. Growth‐development trade‐offs have been considered from observations of a negative correlation between growth and development rates among populations. In this study, we examined not only interpopulation but also intrapopulation correlations in a fish Oryzias latipes. Rearing experiments revealed that larvae from a high‐latitude population grew faster but metamorphosed at larger sizes than larvae from a low‐latitude population. Moreover, within each population, individuals that grew faster tended to delay metamorphosis. The parallelism of the negative interpopulation and intrapopulation correlations between growth and development rates strongly support a growth‐development trade‐off. Observations of swimming behaviors revealed that high‐latitude, fast‐growing juveniles showed lower steady‐swimming and burst‐swimming speeds, probably reflecting that their underdeveloped skeletal and muscular structures translated into the poorer swimming performances. These results suggest that the higher growth capacity of high‐latitude O. latipes has evolved at the expense of fast development.
The General Environment Fit Scale: A Factor Analysis and Test of Convergent Construct Validity
Authors: Beasley Christopher R. , Jason Leonard A. , Miller Steven A.
Published: November 2011

Person‐environment fit (P‐E fit) was initially espoused as an important construct in the field of community psychology; however, most of the theoretical and empirical development of the construct has been conducted by the industrial/organizational (I/O) psychologists and business management fields. In the current study, the GEFS—a P‐E fit measure that was developed from organizational perspectives on fit—was administered to 246 attendees of an annual convention for residents and alumni of Oxford House, a network of over 1,400 mutual‐help addiction recovery homes. The authors conducted confirmatory factor and convergent construct validity analyses with the GEFS. The results suggested that the theoretical factor structure of the measure adequately fit the data and provided limited support for the measure's validity. Sufficient supply of resident needs by the Oxford House and similarity between residents and their housemates predicted satisfaction with the recovery home, but only perceived similarity to housemates predicted how long residents intended to stay in the Oxford Houses.
Calcium supplementation prevents obesity, hyperleptinaemia and hyperglycaemia in adult rats programmed by early weaning
Authors: Lopes Nobre Jessica , Lisboa Patricia Cristina , da Silva Lima Natália , Franco Juliana Gastão , Firmino Nogueira Neto José , de Moura Egberto Gaspar , de Oliveira Elaine
Published: November 2011

It is known that Ca therapy may have anti-obesity effects. Since early weaning leads to obesity, hyperleptinaemia and insulin resistance, we studied the effect of dietary Ca supplementation in a rat model. Lactating rats were separated into two groups: early weaning (EW) – dams were wrapped with a bandage to interrupt lactation in the last 3 d of lactation and control (C) – dams whose pups had free access to milk during the entire lactation period (21 d). At 120 d, EW and C offspring were subdivided into four groups: (1) C, received standard diet; (2) CCa, received Ca supplementation (10 g of calcium carbonate/kg of rat chow); (3) EW, received standard diet; (4) EWCa, received Ca supplementation similar to CCa. The rats were killed at 180 d. The significance level was atP < 0·05. Adult EW offspring displayed hyperphagia (28 %), higher body weight (9 %) and adiposity (77 %), hyperleptinaemia (twofold increase), hypertriacylglycerolaemia (64 %), hyperglycaemia (16 %), higher insulin resistance index (38 %) and higher serum 25-hydroxyvitamin D3(fourfold increase), but lower adiponectinaemia:adipose tissue ratio (44 %). In addition, they showed Janus tyrosine kinase 2 and phosphorylated signal transducer and activator of transcription 3 underexpression in hypothalamus (36 and 34 %, respectively), suggesting leptin resistance. Supplementation of Ca for 2 months normalised these disorders. The EW group had no change in serum insulin, thyroxine or triiodothyronine, and Ca treatment did not alter these hormones. In conclusion, we reinforced that early weaning leads to late development of some components of the metabolic syndrome and leptin resistance. Dietary Ca supplementation seems to protect against the development of endocrine and metabolic disorders in EW offspring, maybe through vitamin D inhibition.
Curcumin-supplemented yoghurt improves physiological and biochemical markers of experimental diabetes
Authors: Gutierres Vânia O. , Pinheiro Clara M. , Assis Renata P. , Vendramini Regina C. , Pepato Maria T. , Brunetti Iguatemy L.
Published: November 2011

We investigated the effects of prolonged treatment of diabetic rats with curcumin-supplemented yoghurt on the physiological and biochemical changes associated with diabetes mellitus. An established metabolic cage model was used to assess these changes in three groups of streptozotocin-diabetic rats which had been administered, by gavage, curcumin blended into yoghurt in the doses of 30, 60 and 90 mg/kg body weight (BW) per d (groups DC30, DC60, DC90) for 31 d. One group of non-diabetic rats was also treated with 90 mg/kg BW per d curcumin (NDC90). Three control groups of diabetic animals received water (DW), yoghurt (DY) and insulin at 27·78 μmol/d by subcutaneous injection (DI). Also, two groups of non-diabetic animals received water (NDW) and yoghurt (NDY). Groups DI and DC90 exhibited significant falls, relative to DW and DY, in food and water intake, urine volume, glycaemia, urinary urea and glucose, proteinuria, serum TAG and activities of aspartate and alanine aminotransferases, and higher hepatic glycogen and BW. These improvements were greater in DI than in DC90. No difference was observed in the serum levels of total cholesterol or HDL-cholesterol, or in the masses of adipose and muscular tissues, between DC90 and DW or DY. Moreover, the improvements in curcumin-treated rats, relative to DW and DY, were significant and dose-dependent. The NDC90 group also showed no difference from the NDW or NDY groups, in any of the markers for diabetes. In conclusion, curcumin mixed into yoghurt at the highest dose tested exhibited anti-diabetic activity, improving significantly most of the markers assessed in this study.
Maternal intake of fatty acids during pregnancy and allergies in the offspring
Authors: Nwaru Bright I. , Erkkola Maijaliisa , Lumia Mirka , Kronberg-Kippilä Carina , Ahonen Suvi , Kaila Minna , Ilonen Jorma , Simell Olli , Knip Mikael , Veijola Riitta , Virtanen Suvi M.
Published: November 2011

Fatty acids (FA) are known to have a number of immunological effects and, accordingly, may play a role in the development of allergic diseases. We investigated the effect of maternal intake of FA during pregnancy on the risk of allergic rhinitis, wheeze and atopic eczema in children aged 5 years. The present study analysed data from the Finnish Type 1 Diabetes Prediction and Prevention Nutrition Study, a population-based birth cohort study with a 5-year follow-up. Complete information on maternal diet (assessed by a validated FFQ) and International Study of Asthma and Allergies in Childhood-based allergic outcomes was available for 2441 children. Cox proportional regression and logistic regression were used for the analyses. After adjusting for potential confounding variables, high maternal consumption of butter and butter spreads (hazard ratio (HR) 1·33; 95 % CI 1·03, 1·71) and higher ratio of n-6:n-3 FA (HR 1·37; 95 % CI 1·07, 1·77) during pregnancy were associated with an increased risk of allergic rhinitis in the offspring by 5 years of age. High maternal intakes of total PUFA (HR 0·71; 95 % CI 0·52, 0·96) and α-linolenic FA (HR 0·73; 95 % CI 0·54, 0·98) were associated with a decreased risk of allergic rhinitis. However, these results lost their significance after adjustment for multiple comparisons. Overall, our data suggest that maternal consumption of butter, the ratio of n-6:n-3 FA and intake of PUFA and α-linolenic FA during pregnancy may be potential determinants of allergic rhinitis in the offspring.
THE CHRONOTOPE OF ISTANBUL IN ORHAN PAMUK'S MEMOIR ISTANBUL
Authors: Erol Sibel
Published: November 2011

In his memoir Istanbul, Orhan Pamuk argues that Istanbul is the site of intense hüzün (melancholy) caused by the loss of the Ottoman Empire. Furthermore, like other inhabitants of the city, that is, Istanbullus, his life is imbued with this inescapable melancholy. Taking issue with the apparent anachronism of Pamuk's historical argument, I show how he constructs and naturalizes this association between Istanbul, melancholy, and loss of empire by creating a literary genealogy for his claim. Using the Bakhtinian concept of chronotope (a schema that recognizes and explains the patterns of fusion of time, space, and emotion as thematic constellation or narrative pattern), I argue that what Pamuk identifies in and derives from the writings of his predecessors is the chronotope of Istanbul. I show how Pamuk constructs the hybrid literary canon and tradition (that references Balzac and Joyce as much as it does Beyatlı and Tanpınar) in which he locates himself in the process of deriving this chronotope.
Introduction
Authors: Selim Samah
Published: November 2011

The question that the five literary scholars participating in this roundtable have set out to answer is the following: “How has ‘theory’ affected the field of Arabic literature in the Unites States and vice versa?” By theory, we understand both the entire range of poststructuralist critical practice that emerged through continental philosophy in the 1960s and the canonical disciplinary object that came to dominate departments of literature in the United States in the 1980s. Most of us were beginning our graduate careers around this latter decade, in departments of Middle East studies or English and comparative literature, and experienced firsthand that moment of encounter referred to in the following essays. A couple of decades later, and irrespective of our institutional locations, all of us, as a matter of course, continue to work at the intersection between national traditions and the world of theory, as do our colleagues in the field and our graduate students. At the same time, there was a feeling amongst us of being at a crossroads of sorts—a certain sense of malaise, or perhaps urgency, that manifested itself in a recurring set of questions about the field here and now: questions about history and reading, about translation and audiences, and about institutional and cultural politics, that all somehow emerged from the era of sanctions and war during which we came of age and that now haunt the time of revolution in which we live. If the present roundtable raises more questions than it answers, we hope that it will at least initiate a broader discussion about the practice and purpose of the discipline of Arabic literature in the American humanities today.
EDITORIAL FOREWORD
Authors: Baron Beth , Pursley Sara
Published: November 2011

The first three articles in this issue, grouped under the subtitle “Insurgency, State Formation, Counterinsurgency,” all deal with historical aspects of nationalism and state-building in the 20th century and resonate with contemporary politics in the Arab world. Starting with Egypt, Omnia El Shakry looks at how student demonstrations in 1935 and 1936 helped usher in the “figure of youth as an insurgent subject of politics.” This discourse placed youth at the vanguard of nationalist struggle and social change in Egypt “but only insofar as they could enact a non-antagonistic conception of politics grounded in national unity.” It also foreshadowed the emergence of a discourse of adolescent psychology in the 1940s, in which adolescence was “reconfigured as a psychological stage of social adjustment, sexual repression, and existential anomie.” Given the emphasis on the role of youth in the 2011 uprisings in Arab states, the article has potential theoretical implications for analyses of current events and discourse.
The effects of cultivar, season and site on variation in grain N concentration and N use efficiency of winter wheat in Northern Ireland
Authors: WHITE E.
Published: November 2011

A detailed study of nitrogen use efficiency (NUE) and its components in three cultivars of winter wheat, Hereward, Rialto and Riband was undertaken in cultivar trials conducted in Northern Ireland in 1998 and 1999. Yield, grain N concentration, harvest index (HI), nitrogen harvest index (NHI), N uptake efficiency (NUpE), total N uptake, grain N off-take, N utilization efficiency (NUtE) and NUE itself all showed significant variation between sites. Cvars Hereward and Rialto had similar mean values across all the sites for many of the characteristics, with Riband usually differing. In all but one characteristic, grain N concentration, the responses of the three cultivars varied significantly from trial to trial and this, along with the substantial variation between sites, indicates that genetic control of the characteristics is partial. The amount of N applied as fertilizer accounted for little of the variation among the trials with weak associations for NUpE, which decreased, and grain yield, which increased with increasing fertilizer N. Neither grain yield nor NUE was associated with the amount of N taken up by the crop, but grain N concentration increased and NUtE decreased significantly. HI and NHI differed significantly among the cultivars, diverging at higher N uptakes, with Hereward and Rialto being similar and distinctly different from Riband. Grain yield was only weakly associated with NUpE but was strongly and positively associated with NUtE and NUE. The strong negative association between NUtE and NUpE highlights the potential and the urgency of understanding factors influencing uptake of nitrogen by crops. The extent of the non-genetic, i.e. environmental and management, variation in the characteristics, along with the relative similarity of the cultivar means, throws up a challenge to plant breeders, agronomists and researchers wishing to improve NUE genetically and through management. As with yield and other characteristics, a large number of trials will be required to identify consistent differences in NUE among cultivars. Thus, while mechanisms underlying NUE, NUpE and NUtE need to be understood, the possibility of using the HGCA UK Recommended List database to investigate NUE and identify cultivars with improved NUE should also be considered. Since in each of the HGCA trials cultivars have access to the same available N, and since grain yield=available N×NUE, grain yield itself is a surrogate for the NUE of cultivars. Grain N concentration is only determined in a few cultivars at present but could be used as an indicator of optimal N availability in individual trials, allowing variation in NUE of cultivars in response to agro-ecological factors on NUE to be studied.
A MULTILEVEL ANALYSIS OF THE DETERMINANTS OF HIGH-RISK SEXUAL BEHAVIOUR IN SUB-SAHARAN AFRICA
Authors: UCHUDI JOSEPH , MAGADI MONICA , MOSTAZIR MOHAMMOD
Published: November 2011

A number of authors have identified multiple concurrent sexual partnerships by both men and women to lie at the root of the HIV/AIDS epidemic in sub-Saharan Africa. This study applies multilevel models to Demographic and Health Survey data collected during 2003–2008 in 20 sub-Saharan African countries to examine the influence of social and cultural context on involvement with multiple sexual partnerships in the region, above and beyond the effects of individual characteristics. The findings provide support for the ecological argument that health behaviours are shaped and determined by societal conditions, in addition to the effects of individual and household characteristics. Involvement with multiple sex partners is most prevalent in societies in which sexual norms are widely permissive and where polygyny is common. Individual autonomy is substantial and attitudes towards sexuality are more liberal among men and women who live in communities in which sexual norms are widely permissive. Men and women who are most likely to have multiple sex partners in the sub-Saharan region are those who initiated sexual activity earlier and those who have the individual attributes (e.g. young age, urban residence, education, media exposure and working for cash and away from home) that bring to them more rights and/or decision-making autonomy, but not necessarily more financial resources and economic security (mostly among women). On the other hand, involvement with multiple partners is determined by cultural norms (i.e. permissive sexual norms) and social change (i.e. mass education, expansion of cash employment). The findings suggest a number of opportunities for more effective policy and programmatic responses to curb the prevalence of multiple partnerships in sub-Saharan Africa.
Nutritional determinants of cognitive aging and dementia
Authors: Morris Martha C.
Published: November 2011

The objective of this review is to provide an overview of nutritional factors involved in cognitive aging and dementia with a focus on nutrients that are also important in neurocognitive development. Several dietary components were targeted, including antioxidant nutrients, dietary fats and B-vitamins. A critical review of the literature on each nutrient group is presented, beginning with laboratory and animal studies of the underlying biological mechanisms, followed by prospective epidemiological studies and randomised clinical trials. The evidence to date is fairly strong for protective associations of vitamin E from food sources, then-3 fatty acid, DHA, found in fish, a high ratio of polyunsaturated to saturated fats, and vitamin B12and folate. Attention to the level of nutrient intake is crucial for interpreting the literature and the inconsistencies across studies. Most of the epidemiological studies that observe associations have sufficient numbers of individuals who have both low and adequate nutrient status. Few of the randomised clinical trials are designed to target participants who have low baseline status before randomising to vitamin supplement treatments, and this may have resulted in negative findings.Post-hocanalyses by some of the trials reveal vitamin effects in individuals with low baseline intakes. The field of diet and dementia is a relatively young area of study. Much further work needs to be done to understand dietary determinants of cognitive aging and diseases. Further, these studies must be particularly focused on the levels of nutrient intake or status that confer optimum or suboptimal brain functioning.
Dissociation and emotion regulation in borderline personality disorder
Authors: Barnow S. , Limberg A. , Stopsack M. , Spitzer C. , Grabe H. J. , Freyberger H. J. , Hamm A.
Published: November 2011

Background

Although some evidence suggests that borderline personality disorder (BPD) is primarily a disorder of the emotion regulation system, findings remain inconsistent. One potential explanation for this is the moderating role of dissociation.

Method

In this study, 33 female subjects with BPD and 26 healthy controls (HC; matched by education level and nicotine intake) were presented idiographic aversive, standard unpleasant and neutral scripts. Modulation of startle reflex and electrodermal responses (skin conductance level; SCL) were measured during imagery of emotional and neutral scripts. Additionally, self-reports of emotional experience (valence and arousal) and present-state dissociation were assessed.

Results

Patients with BPD showed elevated levels of dissociative experiences during testing. Present-state dissociation mediated group differences in SCL and startle response between the HC and BPD groups.

Conclusions

These results suggest that careful attention must be paid to the moderating effect of dissociative symptoms on the psychophysiological responses of BPD patients. Furthermore, the findings have important implications for the assessment and treatment of BPD, including the need to carefully assess BPD patients for dissociative symptoms and to incorporate the treatment of dissociation.
Evanescent Schölte waves of arbitrary profile and direction
Authors: PARKER D. F.
Published: November 2011

Schölte waves, waves bound to the interface between a fluid and an elastic half-space, are, for many material combinations, evanescent; as they propagate, they are damped due to radiation. A representation of the general evanescent Schölte wave is here obtained in terms of a solution to the membrane equation with complex speed, linked, at each instant, to a complex-valued harmonic function in a half-space. This derivation generalises one obtained recently for (non-evanescent) Rayleigh, Stoneley and Schölte waves. An alternative description is also obtained, in which the time-evolution of the normal displacement of the interface satisfies a first-order, complex-valued, non-local evolution equation. Amongst some explicit solutions obtained are decaying solutions allied to a general solution to the Helmholtz equation, and a solution closely related to a Gaussian beam. In the plane–strain case, the general Schölte wave splits into two disturbances, one right-travelling and one left-travelling, each being described at all times in terms of a harmonic function in a half-plane, decaying with depth yet having arbitrary boundary values. This representation highlights the dual elliptic–hyperbolic nature typical of guided waves and gives a surprisingly compact representation for the two-dimensional case.
Kawasaki disease in Jordan: demographics, presentation, and outcome
Authors: AL-Ammouri Iyad , Al-Wahsh Shorouk , Khuri-Bulos Najwa
Published: November 2011

Kawasaki disease is the leading cause of acquired coronary artery disease in young children. There is a lack of data on Kawasaki disease and its effect on coronary arteries in Jordan and other developing countries. We report clinical and demographic data of Kawasaki disease in Jordan from a single institution, with emphasis on cardiac involvement and short to intermediate follow-up. Review of the medical records of 34 patients with Kawasaki disease from 1997 to 2010 was done for clinical and demographic variables. Echocardiographic and angiographic images were reviewed for patients at presentation and follow-up. The median age at presentation was 19 months, ranging from 2 months to 8 years, with a male to female ratio of 3.9:1. In all, 12 patients (35%) had incomplete Kawasaki disease. There was a high incidence of coronary artery involvement (41%), where 20.5% had aneurysms and 20.5% had ectasia without aneurysm. Most coronary aneurysms were present at the time of diagnosis. The only independent variable for prediction of coronary involvement was age, with an odds ratio of 0.63 per year (95% confidence interval 0.41–0.95).
Imaging of Vascular Smooth Muscle Cells with Soft X-Ray Spectromicroscopy
Authors: Sedlmair Julia , Gleber Sophie-Charlotte , Mert Semra Öztürk , Bertilson Michael , von Hofsten Olov , Thieme Jürgen , Pfohl Thomas
Published: November 2011

Using X-ray microscopy and spectromicroscopy, vascular smooth muscle cells (VSMCs) were imaged, prepared without using additional embedding material or staining, but by applying simple, noncryo fixation techniques. The cells were imaged with a compact source transmission X-ray microscope and a scanning transmission X-ray microscope (STXM). With the STXM, spectromicroscopy was performed at the C K-edge and the Ca LIII,II-edges. VSMCs were chosen because of their high amount of actin stress fibers, so that the actin cytoskeleton should be visible. Other parts of the cell, such as the nucleus and organelles, were also identified from the micrographs. Both in the spectra and the images, the effects of the different preparation procedures were observable. Furthermore, Ca hotspots were detected and their density is determined.
A comprehensive analysis of free‐space and guided‐wave techniques for extracting the permeability and permittivity of materials using reflection‐only measurements
Authors: Fenner R. A. , Rothwell E. J. , Frasch L. L.
Published: November 2011

The electromagnetic characterization of layered materials is often performed using reflection‐only measurements, and through the years several different techniques have been developed to accomplish this both in the laboratory and in situ. It is shown in this paper that the majority of these methods are variations on a single approach, and that closed‐form expressions are available to obtain the permittivity and permeability from the measurements. The approach is applicable to free‐space (plane wave) measurements, waveguide (non‐TEM) measurements, and transmission line (TEM) measurements, and is based on varying the underlying structure of the material stack to obtain independent measurements. Because the formulation is based on specifying the impedances of adjacent regions, the same formula for permittivity and permeability is valid regardless of the complexity of the stack containing the material under test. Examples of several techniques are given using free‐space, waveguide, and transmission‐line measurements of both dielectric materials and magnetic absorbing materials.
Random copolymer of styrene and diene derivatives via anionic living polymerization followed by intramolecular Friedel–Crafts cyclization for high-performance thermoplastics
Authors: Nakahara Atsuhiro , Satoh Kotaro , Kamigaito Masami
Published: November 2011

Rubbery random copolymers of styrenes and dienes prepared via anionic living polymerizations were intramolecularly cyclized into high-performance thermoplastics.
Inhibition of glutaminyl cyclase attenuates cell migration modulated by monocyte chemoattractant proteins
Authors: Chen Yi-Ling , Huang Kai-Fa , Kuo Wen-Chih , Lo Yan-Chung , Lee Yu-May , Wang Andrew H.-J.
Published: November 2011

QC (glutaminyl cyclase) catalyses the formation of N-terminal pGlu (pyroglutamate) in peptides and proteins. pGlu formation in chemoattractants may participate in the regulation of macrophage activation and migration. However, a clear molecular mechanism for the regulation is lacking. The present study examines the role of QC-mediated pGlu formation on MCPs (monocyte chemoattractant proteins) in inflammation. We demonstrated in vitro the pGlu formation on MCPs by QC using MS. A potent QC inhibitor, PBD150, significantly reduced the N-terminal uncyclized-MCP-stimulated monocyte migration, whereas pGlu-containing MCP-induced cell migration was unaffected. QC small interfering RNA revealed a similar inhibitory effect. Lastly, we demonstrated that inhibiting QC can attenuate cell migration by lipopolysaccharide. These results strongly suggest that QC-catalysed N-terminal pGlu formation of MCPs is required for monocyte migration and provide new insights into the role of QC in the inflammation process. Our results also suggest that QC could be a drug target for some inflammatory disorders.
Pancreatic Autoantibodies, HLA DR and PTPN22 Polymorphisms in First Degree Relatives of Patients with Type 1 Diabetes and Multiethnic Background
Authors: Barone B. , Dantas J. , Almeida M. , Anna-Gomes B. , Bencke-Gongalves M.D. , Albernaz M. , Rodrigues M. , Zajdenverg L. , Kupfer R. , Milech A. , Rodacki M. , Oliveira J.E.
Published: November 2011

To evaluate the prevalence of pancreatic auto-antibodies (PAb) as well as its relationship with HLA DR B1 and PTPN22 polymorphisms in first degree relatives (FDR) of Brazilian patients with Type 1 diabetes (T1D) and multiethnic background.

FDR of patients with T1D were interviewed and blood was sampled for PAb measurement, HLA DRB1 and PTPN22 genotyping. Genotyping was also performed in index cases.

In FDR (n=78), 16.7% presented at least one PAb. These individuals had a higher prevalence of HLA DRB1* 03 than others (p=0.03), without differences in PTPN22 genotyping. While the genetic profile was similar in FDR with PAb and their index cases, those without PAb had a lower frequency of HLA DR B1 * 03 than their correspondent patients (p=0.009).

In this multiethnic population, a significant proportion of FDR of T1D patients had PAb, which was associated with HLA DR B1 * 03 but not with the PTPN22 polymorphism.

Type 1 diabetes and relatives: Antibodies, genetics
In-plane polarization anisotropy of ground state optical intensity in InAs/GaAs quantum dots
Authors: Usman Muhammad
Published: November 2011

The design of optical devices such as lasers and semiconductor optical amplifiers for telecommunication applications requires polarization insensitive optical emissions in the region of 1500 nm. Recent experimental measurements of the optical properties of stacked quantum dots have demonstrated that this can be achieved via exploitation of inter-dot strain interactions. In particular, the relatively large aspect ratio (AR) of quantum dots in the optically active layers of such stacks provide a two-fold advantage, both by inducing a red shift of the gap wavelength above 1300 nm, and increasing the TM001-mode, thereby decreasing the anisotropy of the polarization response. However, in large aspect ratio quantum dots (AR > 0.25), the hole confinement is significantly modified compared with that in lower AR dots—this modified confinement is manifest in the interfacial confinement of holes in the system. Since the contributions to the ground state optical intensity (GSOI) are dominated by lower-lying valence states, we therefore propose that the room temperature GSOI be a cumulative sum of optical transitions from multiple valence states. This then extends previous theoretical studies of flat (low AR) quantum dots, in which contributions arising only from the highest valence state or optical transitions between individual valence states were considered. The interfacial hole distributions also increases in-plane anisotropy in tall (high AR) quantum dots (TE110 ≠ TE−110), an effect that has not been previously observed in flat quantum dots. Thus, a directional degree of polarization (DOP) should be measured (or calculated) to fully characterize the polarization response of quantum dot stacks. Previous theoretical and experimental studies have considered only a single value of DOP: either [110] or [−110].
Large eddy simulation subfilter modeling of soot-turbulence interactions
Authors: Mueller Michael E. , Pitsch Heinz
Published: November 2011

The small-scale interactions between turbulence, chemistry, and soot have a profound effect on the soot formation, growth, and destruction processes in turbulent reacting flows. In this work, the small-scale subfilter interactions between turbulence and soot are modeled using a presumed subfilter PDF for the statistical moments of the soot number density function. Due to a very large (infinite) Schmidt number, soot is confined to very thin structures. In addition, soot is formed initially from Polycyclic Aromatic Hydrocarbons, which exhibit a strong sensitivity to the local scalar dissipation rate in the flow field. These interactions of soot with the gas-phase chemistry, molecular transport, and turbulence result in very high spatial and temporal intermittency. Therefore, the soot subfilter PDF is presumed to be a pair of delta distributions with a sooting mode and a non-sooting mode. In addition to the mean values of the scalars, one additional parameter is needed to specify this distribution. The presumed soot subfilter PDF approach is evaluated a priori using a recent two-dimensional direct numerical simulation (DNS) database of soot evolution in a nonpremixed flame. The analysis shows that predictions of the soot intermittency as well as the soot source terms are improved with this presumed soot subfilter PDF approach compared to simply using the mean values of the soot scalars. Several choices for specifying the additional parameter of the PDF are also evaluated with the database. The results show that the parameter is best specified using the second moment of the soot number density. In addition, the transport equation for the second moment of the number density is briefly discussed. A model for the lone unclosed term is proposed and evaluated with the DNS data.
Controlling the fixed charge and passivation properties of Si(100)/Al2O3 interfaces using ultrathin SiO2 interlayers synthesized by atomic layer deposition
Authors: Dingemans G. , Terlinden N. M. , Verheijen M. A. , van de Sanden M. C. M. , Kessels W. M. M.
Published: November 2011

Al2O3 synthesized by atomic layer deposition (ALD) on H-terminated Si(100) exhibits a very thin (∼1 nm) interfacial SiOx layer. At this interface, a high fixed negative charge density, Qf, is present after annealing which contributes to ultralow surface recombination velocities <2 cm/s. Here, we identify the thickness of the interfacial SiO2 layer as a key parameter determining Qf. The SiO2 thickness was controlled by intentionally growing ultrathin SiO2 interlayers (0.7−30 nm) by ALD. Optical second-harmonic generation spectroscopy revealed a marked decrease in Qf for increasing SiO2 thickness between 0 and 5 nm. This phenomenon is consistent with charge injection across the interfacial layer during annealing. For thicker SiO2 interlayers (>∼5 nm), the polarity of the effective charge density changed from negative to positive. The observed changes in Qf and the associated field-effect passivation had a significant influence on the injection-level-dependent minority carrier lifetime of Si.
A dynamic investigation of observable void growth and coalescence in pure copper sheets
Authors: Dongfang Ma , Danian Chen , Shanxing Wu , Huanran Wang , Canyuan Cai , Gaotao Deng
Published: November 2011

A combined experimental, theoretical, and numerical investigation of dynamic growth and coalescence of drilled voids in pure copper sheets was performed to visualize void growth and coalescence in a controlled matter. The dynamic constitutive model of the pure copper determined from the first tension loading in the optimized tensile split Hopkinson bar (TSHB) tests for pure copper sheets was adjusted in numerically simulating the large deformation of pure copper sheets generated by the multi-tension loading in the TSHB tests and recorded by a high speed camera. The dynamic growth, coalescence, and evolution post coalescence of drilled simplest cluster voids in pure copper sheets subjected to the multi-tension loading in the TSHB tests were recorded by the high speed camera and simulated by using the adjusted constitutive model of the pure copper and the different criteria for void coalescence. Based on Bandstra’s work [J. P. Bandstra et al. Mater. Sci. Eng. A 249, 46 (1998); J. P. Bandstra and D. A. Koss, Mater. Sci. Eng. A 319-321, 490 (2001)], this study presented a stress triaxiality and strain rate (STSR) dependent failure criterion for void coalescence to reveal the void coalescence process. The experimentally recorded void evolution at a certain average strain of pure copper sheets was compared with the numerically simulated results, which involved the STSR dependent failure criterion, the localized Thomason criterion [P. F. Thomason, Ductile Fracture of Metals (Pergamon, 1990); Fatigue Frac. Eng. Matter Struct. 21, 1105 (1998)], and Brown-Embury criterion [L. M. Brown and D. Embury, Proceedings of the Third International Conference on Strength of Metals and Alloys (Institute of Metals, London, 1973), pp. 164–173]. The validity of void coalescence criteria was assessed: the STSR dependent failure criterion could be used to describe the void coalescence process while the localized Thomason criterion and Brown-Embury criterion for void cluster could also match the process of void coalescence to a certain extent.
Substrate nitridation induced modulations in transport properties of wurtzite GaN/p-Si (100) heterojunctions grown by molecular beam epitaxy
Authors: Bhat Thirumaleshwara N. , Rajpalke Mohana K. , Roul Basanta , Kumar Mahesh , Krupanidhi S. B.
Published: November 2011

Phase pure wurtzite GaN films were grown on Si (100) substrates by introducing a silicon nitride layer followed by low temperature GaN growth as buffer layers. GaN films grown directly on Si (100) were found to be phase mixtured, containing both cubic (β) and hexagonal (α) modifications. The x-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy studies reveal that the significant enhancement in the structural as well as in the optical properties of GaN films grown with silicon nitride buffer layer grown at 800 °C when compared to the samples grown in the absence of silicon nitride buffer layer and with silicon nitride buffer layer grown at 600 °C. Core-level photoelectron spectroscopy of SixNy layers reveals the sources for superior qualities of GaN epilayers grown with the high temperature substrate nitridation process. The discussion has been carried out on the typical inverted rectification behavior exhibited by n-GaN/p-Si heterojunctions. Considerable modulation in the transport mechanism was observed with the nitridation conditions. The heterojunction fabricated with the sample of substrate nitridation at high temperature exhibited superior rectifying nature with reduced trap concentrations. Lowest ideality factors (∼1.5) were observed in the heterojunctions grown with high temperature substrate nitridation which is attributed to the recombination tunneling at the space charge region transport mechanism at lower voltages and at higher voltages space charge limited current conduction is the dominating transport mechanism. Whereas, thermally generated carrier tunneling and recombination tunneling are the dominating transport mechanisms in the heterojunctions grown without substrate nitridation and low temperature substrate nitridation, respectively.
Sealing SU-8 microfluidic channels using PDMS
Authors: Zhang Zhiyi , Zhao Ping , Xiao Gaozhi , Watts Benjamin R. , Xu Changqing
Published: November 2011

A simple method of irreversibly sealing SU-8 microfluidic channels using PDMS is reported in this paper. The method is based on inducing a chemical reaction between PDMS and SU-8 by first generating amino groups on PDMS surface using N2 plasma treatment, then allowing the amino groups to react with the residual epoxy groups on SU-8 surface at an elevated temperature. The N2 plasma treatment of PDMS can be conducted using an ordinary plasma chamber and high purity N2, while the residual epoxy groups on SU-8 surface can be preserved by post-exposure baking SU-8 at a temperature no higher than 95 °C. The resultant chemical bonding between PDMS and SU-8 using the method create an interface that can withstand a stress that is greater than the bulk strength of PDMS. The bond is permanent and is long-term resistant to water. The method was applied in fabricating SU-8 microfluidi-photonic integrated devices, and the obtained devices were tested to show desirable performance.
Transmission electron microscopy study of GaInNAs(Sb) thin films grown by atomic hydrogen-assisted molecular beam epitaxy
Authors: Oshima R. , Huang J. Y. , Miyashita N. , Matsubara K. , Okada Y. , Ponce F. A.
Published: November 2011

The quaternary GaInNAs is a promising material system for use in next generation multijunction photovoltaic devices. We have investigated the effect of introducing antimony on the growth by using transmission electron microscopy and energy dispersive x-ray (EDX) spectroscopy. Two-dimensional growth was observed in GaInNAs films with striation features associated with compositional fluctuation and nanometer scale elemental segregation on the growth front. On the contrary, GaInNAsSb films exhibit uniform contrast throughout. EDX profile indicates uniform compositional distribution, as antimony atoms suppress the surface mobilites of adatoms resulting in a lower probability to generate the favored bonds, such as Ga-N and In-As.
Vertically integrated silicon-germanium nanowire field-effect transistor
Authors: Rosaz G. , Salem B. , Pauc N. , Potié A. , Gentile P. , Baron T.
Published: November 2011

We demonstrate in this paper the possibility to vertically integrate SiGe nanowires in order to use them as vertical channel for field-effect transistors (FETs). We report a threshold voltage close to 3.9 V, an ION/IOFF ratio of 104. The subthreshold slope was estimated to be around 0.9 V/decade and explained by a high traps density at the nanowire core/oxide shell interface with an estimated density of interface traps Dit ∼ 1.2 × 1013 cm−2 eV−1. Comparisons are made with both vertical Si and horizontal SiGe FETs performances.
Electrodynamics and quantum capacity of LixFePO4 battery material
Authors: Craco L. , Leoni S.
Published: November 2011

We report on optical conductivity and dielectric properties of pure and electron-doped FePO4, an attractive material for the next generation of lithium-ion batteries. Using the local-density-approximation plus dynamical mean-field theory for the real multi-orbital case we show the importance of incoherence-induced high energy continuum in LixFePO4. Our results for the dielectric function allow us to elucidate relevant features seen in experimental potential-capacity profiles and serve as a theoretical basis for postulating that potential-capacity and electrodynamic responses are microscopically entangled in nature. Our microscopic description of quantum capacity is expected to be applicable to battery materials in general.
An ultrabroad terahertz bandpass filter based on multiple-resonance excitation of a composite metamaterial
Authors: Chiang Yi-Ju , Yang Chan-Shan , Yang Yu-Hang , Pan Ci-Ling , Yen Ta-Jen
Published: November 2011

We experimentally present an ultrabroad terahertz (THz) bandpass filter based on a composite metamaterial (CMM) by exciting its multiple resonances. This metamaterial-based filter, consisting of a metal-dielectric-metal sandwiched structure, possesses a notable spectral-filtering capability with a 0.5-THz-broad bandwidth and excellent band-edge transitions of 140% THz and 182% THz in the THz-gap region. Furthermore, we manifest the mechanism for each of the resonances and the coupling within the composite metamaterial. This realization enables the capacity for engineering the electromagnetic properties to develop other complex optical functionalities. An example of a high-profile dualband THz bandpass filter is also proposed theoretically in this work.
Polarized Raman microscopy of anisotropic stress relaxation in strained-Si-on-insulator stripes
Authors: Poborchii Vladimir , Tada Tetsuya , Usuda Koji , Kanayama Toshihiko
Published: November 2011

Using a high-numerical-aperture lens, we studied strain relaxation in the [110]-oriented strained-silicon-on-insulator (SSOI) stripes. A complete set of Si optical phonon Raman bands was observed. For a 50 nm thick SSOI, the symmetrical biaxial tensile stress in a relatively wide stripe is found to transform to the uniaxial [110] stress at its edge. The same uniaxial stress is observed in the narrow stripes with widths <200 nm, the value, probably, being a critical width for a complete SSOI transverse stress relaxation.
Seedling validation of acid soil tolerance of lucerne populations selected in solution culture high in aluminium
Authors: Hayes R. C. , Scott B. J. , Dear B. S. , Li G. D. , Auricht G. C.
Published: November 2011

This study tested the hypothesis that lucerne (Medicago sativa L.) populations selected in solution culture high in aluminium (Al) would increase seedling root growth when grown in an acid soil high in exchangeable Al. Root growth of six elite populations (Aurora C2, UQL-1 C2, T02-011 C1, T02-011 C2, A513 C3 and Sardi 7 C2) selected in high-Al solution culture (SHASC) was compared with that of corresponding parent as well as the Georgia acid soil-tolerant populations in an acid soil in pots grown for 8 days under controlled environmental conditions. Lime was added to the soil to provide contrasts in the severity of stress imposed by low pH and high Al. Averaged across six SHASC populations, total root length increased 19% at pH 4.34 in CaCl2 (35% exchangeable Al) and 26% at pH 5.26 (<1% exchangeable Al) compared with the control populations. At all pH levels SHASC populations showed increased tap root length, total root length (includes lateral roots), root weight and root surface area, but decreased average root diameter compared with the six control populations. A large amount of variability was observed both between and within lucerne populations with three SHASC populations (Aurora C2, UQL-1 C2 and Sardi 7 C2) exhibiting increased root growth at lower pH levels, but little increase in root length at higher pH, consistent with increased tolerance to Al toxicity. This was in contrast to three other SHASC populations (T02-011 C1, T02-011 C2 and A513 C3), which exhibited increased root length at all pH levels, consistent with increased seedling vigour. The Sardi 7 C2 population exhibited the greatest increase in tap root growth with tap root length increasing by 40 and 30% at pH 4.34 and 4.48, respectively, compared with its parent population Sardi 7. This study provides evidence that seedlings of lucerne populations selected in high-Al solution culture can confer significantly improved root and shoot growth in acid soil. It is recommended that such screening be incorporated into lucerne breeding programs to reduce costs in space and time.
The burden of HIV-associated neurocognitive impairment in Australia and its estimates for the future
Authors: Cysique Lucette A. , Bain Margaret P. , Brew Bruce J. , Murray John M.
Published: November 2011

Background
The growing number of older individuals with HIV in Australia implies that the prevalence of dementia and additional HIV-associated neurocognitive disorders will increase. There are currently no estimates of the future burden of neurocognitive disease in this population. Methods: We estimated the number and age profile of people living with HIV to the end of 2009 using HIV/AIDS Registry data, and extrapolated these estimates to 2030. Prevalence of HIV-associated dementia (HAD) from 2005 to 2010 from a large Sydney hospital and cost estimates from the AIDS Dementia and HIV Psychiatry Service were used to estimate future HAD burden and costs. Results: Based on our calculations, the number of HIV-positive individuals in Australia will increase from 16 228 men and 1797 women in 2009 to 26 963 men and 5224 women in 2030, while the number of individuals aged 60+ years will increase from 1140 men and 78 women to 5442 men and 721 women, i.e. a 377% increase of older men and an 825% increase in older women. Based on a 7.8% (157/2004) HAD prevalence obtained from hospital data, individuals with HAD will increase in number from 1314 men and 143 women in 2009 to 2204 men and 421 women in 2030. An estimated 22 men and 2 women with non-HIV dementia in 2009 will increase to 104 men and 12 women by 2030. The annual cost of care will increase from ~$29 million in 2009 to $53 million in 2030, mostly for full-time residential care. Conclusions: Neurocognitive disorders will place an increasing burden on resources, especially as those living with HIV age. Because it is unclear if HAD is an increased risk factor for non-HIV dementia, our calculations may be conservative.
HIV and aging: an overview of an emerging issue
Authors: Slavin Sean , Elliott Julian , Fairley Christopher , French Martyn , Hoy Jennifer , Law Matthew , Lewin Sharon
Published: November 2011

Age related morbidity among people living with HIV has increased as people with the virus live longer. This introduction provides an overview of all the articles which cover a spectrum of issues including particular diseases, the science of immunosenescence and the psycho-social challenges of ageing with HIV. It considers whether a syndrome of accelerated ageing exists among people with HIV finding that evidence is currently lacking to support this theory.