bluuebunny/crossref_metadata_2025 huggingface dataset:
The Cyrenaican Prehistory Project 2012: the sixth season of excavations in the Haua Fteah cave
Authors: Rabett Ryan , Farr Lucy , Hill Evan , Hunt Chris , Lane Ross , Moseley Hazel , Stimpson Christopher , Barker Graeme
Published: April 2014

The paper reports on the sixth season of fieldwork of the Cyrenaican Prehistory Project (CPP) undertaken in September 2012. As in the spring 2012 season, work focussed on the Haua Fteah cave and on studies of materials excavated in previous seasons, with no fieldwork undertaken elsewhere in the Gebel Akhdar. An important discovery, in a sounding excavated below the base of McBurney's 1955 Deep Sounding (Trench S), is of a rockfall or roof collapse conceivably dating to the cold climatic regime of Marine Isotope Stage (MIS) 6 (globally dated to c. 190–130 ka) but more likely the result of a seismic event within MIS 5 (globally dated to c. 130–80 ka). The sediments and associated molluscan fauna in Trench S and in Trench D, a trench being cut down the side of the Deep Sounding, indicate that this part of the cave was at least seasonally waterlogged during the accumulation, probably during MIS 5, of the ~6.5 m of sediment cut through by the Deep Sounding. Evidence for human frequentation of the cave in this period is more or less visible depending on how close the trench area was to standing water as it fluctuated through time. Trench M, the trench being cut down the side of McBurney's Middle Trench, has now reached the depth of the latest Middle Stone Age or Middle Palaeolithic (Levalloiso-Mousterian) industries. The preliminary indications from its excavation are that the transition from the Levalloiso-Mousterian to the blade-based Upper Palaeolithic or Late Stone Age Dabban industry was complex and perhaps protracted, at a time when the climate was oscillating between warm-stage stable environmental conditions and colder and more arid environments. The estimated age of the sediments, c. 50–40 ka, places these oscillations within the earlier part of MIS 3 (globally dated to 60–24 ka), when global climates experienced rapid fluctuations as part of an overall trend to increasing aridity and cold.
Use of laboratory reports as predictors of West Nile virus disease cases, Texas, 2008–2012
Authors: YENDELL S. J. , TAYLOR J. , BIGGERSTAFF B. J. , TABONY L. , STAPLES J. E. , FISCHER M.
Published: April 2014

We evaluated laboratory reports as early indicators of West Nile virus (WNV) disease cases in Texas. We compared WNV laboratory results in the National Electronic Disease Surveillance System Base System (NBS) to WNV disease cases reported to the state health department from 2008 to 2012. We calculated sensitivity and positive predictive value (PPV) of NBS reports, estimated the number of disease cases expected per laboratory report, and determined lead and lag times. The sensitivity and PPV of NBS laboratory reports were 86% and 77%, respectively. For every 10 positive laboratory reports, we expect 9·0 (95% confidence interval 8·9–9·2) reported disease cases. Laboratory reports preceded case reports with a lead time of 7 days. Electronic laboratory reports provided longer lead times than manually entered reports (P < 0·01). NBS laboratory reports are useful estimates of future reported WNV disease cases and may provide timely information for planning public health interventions.
Exploring family relationships through associations of comfort, relatedness states, and life closure in hospice patients: A pilot study
Authors: Hansen Dana M. , Higgins Patricia A. , Warner Camille Beckette , Mayo M. Murray
Published: April 2014

Objective:

Research at the end of life tends to focus on the dying patient's symptoms, often overlooking issues associated with family interactions. However, many families struggle just to maintain or initiate these valuable connections. The purpose of our pilot study was to explore family relationships at the end of life and investigate associations among perceived comfort, relatedness states, and life closure.

Method:

This descriptive study used a cross-sectional design, and a convenience sample (n = 30; 18 women; mean age = 71 years) was recruited from patients admitted to a large not-for-profit hospice in northeastern Ohio. In-person interviews using the Hospice Comfort Questionnaire, Relatedness States Visual Analog Scales, and the Life-Closure Scale provided data for analyses.

Results:

Family interactions that were not associated with the physical tasks of caregiving were related to life closure (r = 0.36, p = 0.001), and life closure and comfort were highly correlated (r = 0.69, p < 0.001). Participants residing in an inpatient setting had higher levels of involvement (t[18] = –2.07, p = 0.05) and comfort in relationships (t[28] = –2.06, p = 0.05) than those in the home setting.

Significance of Results:

This is the first known study investigating the associations among comfort, relatedness, and life closure at the end of life. The majority of participants had high levels of involvement and comfort in their relationships, and they preferred interactions that required minimal effort. Studies that focus on both patients' and family members' perceptions of relationships are needed as well as outcome studies that test simple interventions.
Meanings and experiential outcomes of bodily care in a specialist palliative context
Authors: Håkanson Cecilia , Öhlén Joakim
Published: April 2014

Objective:

The objective of this study was to enhance the depth of existing knowledge about meanings and experiential outcomes of bodily care in the context of an inpatient specialist palliative setting.

Method:

Interpretative phenomenology was chosen as the study sought to explore individuals' lived experiences related to bodily care. Nine participants (five women, four men) of various ages and with various metastasized cancers and bodily-care needs, all from one specialist palliative care ward, participated. Data were collected with repeated narrative interviews and supplementary participating observations. Analysis was informed by van Manen's approach.

Results:

The following meanings and experiential outcomes of bodily care were revealed by our study: maintaining and losing body capability, breaching borders of bodily integrity, being comforted and relieved in bodily-care situations, and being left in distress with unmet needs. These meanings overlap and shape the nature of each other and involve comforting and distressing experiences related to what can be described as conditional dimensions: the particular situation, one's own experiences of the body, and healthcare professionals' approaches.

Significance of results:

The results, based on specialist palliative care patients' experiences, outline the meanings and outcomes that relate to the quintessence and complexity of palliative care, deriving from dying persons' blend of both basic and symptom-oriented bodily-care needs. Moreover, the results outline how these two dimensions of care equally influence whether comfort and well-being are facilitated or not. Considering this, specialist palliative care may consider how to best integrate and acknowledge the value of skilled basic nursing care as part of and complementary to expertise in symptom relief during the trajectories of illness and dying.
High isolation and compact MIMO antenna system with defected shorting wall
Authors: Dai Xi-Wang , Li Long , Wang Zhen-Ye , Liang Chang-Hong
Published: April 2014

In this paper, a compact multiple-input multiple-output (MIMO) antenna system with high isolation is proposed for 2.4 GHz wireless local area network (WLAN) application. The system is composed of two aperture-coupled shorted patch antennas with a spacing of 4 mm (only 0.032λ). The antenna is fed with an H-shaped coupling slot, and the defected shorting wall is used for high isolation. The proposed MIMO system exhibits an isolation of better than −20 dB and a maximum isolation of −43 dB at the central frequency. The envelope correlation coefficient is less than 0.01. The simulated and measured results show that the proposed antenna is a good candidate for MIMO system with higher isolation and better diversity.
Postprandial metabolism and inflammatory markers in overweight adolescents
Authors: Schauren B. C. , Portal V. L. , Beltrami F. G. , dos Santos T. J. , Pellanda L. C.
Published: April 2014

Lifestyle changes have an impact on lipid metabolism. The overload of circulating lipids may lead to endothelial dysfunction, oxidative stress and exaggerated inflammatory response, which may be further aggravated in the presence of overweight. This study aims to describe the postprandial metabolism and inflammatory response in overweight and normal-weight adolescents. Sixty-two adolescents aged 11–18 years were divided into two groups: overweight (OW;n=38) and normal weight (NW;n=24). Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), glucose, insulin, high-sensitivity C-reactive protein (hs-CRP), fibrinogen and leukocytes were collected for fasting and 4 and 6 h after a oral fat tolerance test (OFTT) consisting of a high-fat meal with 1.000 Kcal, 27.4% carbohydrates, 14.7% protein and 57.8% lipids (30.4% saturated, 32.7% monounsaturated, 26.5% polyunsaturated fatty acids and 288 mg TC). Data were analyzed with repeated measures ANOVA, multiple linear regression, and Pearson, Spearman and partial correlations. OW adolescents showed significantly higher fasting values of TC (P=0.036), LDL-C (P=0.010), fibrinogen (P=0.036) and hs-CRP (P=0.004). All variables, except for glucose, increased in response to OFTT, but there were no interactions between group and time. body mass indexz-score was positively correlated to LDL-C, TG, fibrinogen and hs-CRP, and inversely correlated to HDL-C. In conclusion, adolescents with OW showed higher TC, LDL-C and inflammatory markers levels than NW adolescents. These findings have clinical implications for prevention of chronic diseases, as we spend most of our days in a postprandial state.
Sozialer Kontext und antizipierter Alkoholkonsum bei Leistungssportlern
Authors: Ohlert Jeannine , Kleinert Jens
Published: April 2014

Fragestellung: Alkoholkonsum im Leistungssport ist keine Seltenheit. Soziale Einflüsse für oder gegen dieses Verhalten kommen hierbei sowohl von der Trainerseite als auch von den Mannschaftskollegen. Die zentrale Frage der vorliegenden Studie war, inwiefern die Anwesenheit des eigenen Trainers bzw. der Mannschaftskollegen den Alkoholkonsum bei Leistungssportlern beeinflusst. Methodik: Insgesamt 466 LeistungssportlerInnen (43 % Frauen, 57 % Männer; Alter M = 22.0 Jahre) nahmen an einer Online-Befragung teil. Über Vignetten wurde die Wahrscheinlichkeit des Alkoholkonsums bei angenommener Anwesenheit des Trainers oder der Mannschaft erfasst. Ergebnisse: Die Anwesenheit des Trainers ging mit einem Abfall, Anwesenheit von Mannschaftskollegen mit einem Anstieg der Wahrscheinlichkeit für Alkoholgenuss einher. Ein weiterer signifikanter Einflussfaktor war die Gruppenkohäsion der Mannschaft. Schlussfolgerungen: Das Trinkverhalten von Leistungssportlern orientiert sich vermutlich daran, welche Personen in der jeweiligen Situation anwesend sind. Ist die Mannschaft oder Trainingsgemeinschaft zugegen, spielt zusätzlich die Gruppenkohäsion eine Rolle.
Quenching ilmenite with a high-temperature and high-pressure phase using super-high-energy ball milling
Authors: Hashishin Takeshi , Tan Zhenquan , Yamamoto Kazuhiro , Qiu Nan , Kim Jungeum , Numako Chiya , Naka Takashi , Valmalette Jean Christophe , Ohara Satoshi
Published: April 2014

The mass production of highly dense oxides with high-temperature and high-pressure phases allows us to discover functional properties that have never been developed. To date, the quenching of highly dense materials at the gramme-level at ambient atmosphere has never been achieved. Here, we provide evidence of the formation of orthorhombic Fe2TiO4 from trigonal FeTiO3 as a result of the high-temperature (>1250 K) and high-pressure (>23 GPa) condition induced by the high collision energy of 150 gravity generated between steel balls. Ilmenite was steeply quenched by the surrounding atmosphere, when iron-rich ilmenite (Fe2TiO4) with a high-temperature and high-pressure phase was formed by planetary collisions and was released from the collision points between the balls. Our finding allows us to infer that such intense planetary collisions induced by high-energy ball milling contribute to the mass production of a high-temperature and high-pressure phase.
California Niño/Niña
Authors: Yuan Chaoxia , Yamagata Toshio
Published: April 2014

The present study shows the existence of intrinsic coastal air-sea coupled phenomenon in the coastal ocean off Baja California and California in boreal summer for the first time. It contributes significantly to the interannual sea surface temperature (SST) anomalies there. An initial decrease/increase in the equatorward alongshore surface winds weakens/strengthens the coastal upwelling and raises/lowers the coastal SSTs through oceanic mixed-layer processes. The resultant coastal warming/cooling, in turn, heats/cools the overlying atmosphere anomalously, decreases/increases the atmospheric pressure in the lower troposphere, generates an anomalous cross-shore pressure gradient and thus reinforces or maintains the alongshore surface wind anomalies. The regional air-sea coupled phenomenon seems to be analogous to the well-known El Niño/Southern Oscillation (ENSO) in the tropical Pacific but with much smaller time and space scales and may be referred to as California Niño/Niña in its intrinsic sense.
Efficient purification of low molecular weight nitrogen polar compounds from the skin of Bufo bufo gargarizans Cantor by reversed-phase high performance liquid chromatography with a polar-copolymerized C18 stationary phase
Authors: Li Xiaolong , Huang Runqi , Liu Yanfang , Jin Hongli , Wan Huihui , Zhao Jianqiang , Zhao Weijie , Liang Xinmiao
Published: April 2014

A novel method based on the polar-copolymerized C18 stationary phase was developed to separate polar compounds from toad skin.
Solid phase microextraction (SPME) combined with TGA as a technique for guest analysis in crystal engineering
Authors: Fischer Matthew J. , Beatty Alicia M.
Published: April 2014

Guest identification using SPME – a technique for analysis of TGA off-gas that eliminates the need for direct TGA-GC/MS coupling.
Physicochemical properties of pentaglyme–sodium bis(trifluoromethanesulfonyl)amide solvate ionic liquid
Authors: Terada Shoshi , Mandai Toshihiko , Nozawa Risa , Yoshida Kazuki , Ueno Kazuhide , Tsuzuki Seiji , Dokko Kaoru , Watanabe Masayoshi
Published: April 2014

An equimolar complex of pentaglyme (G5) and sodium bis(trifluoromethanesulfonyl)amide (Na[TFSA]) behaves like room-temperature ionic liquids and is a promising electrolyte for Na-ion batteries.
A methanolic extract of Ganoderma lucidum fruiting body inhibits the growth of a gastric cancer cell line and affects cellular autophagy and cell cycle
Authors: Oliveira Marta , Reis Filipa S. , Sousa Diana , Tavares Catarina , Lima Raquel T. , Ferreira Isabel C. F. R. , Santos Tiago dos , Vasconcelos M. Helena
Published: April 2014

The G. lucidum methanolic extract inhibited the growth of a gastric cancer cell line (AGS) by interfering with cellular autophagy and cell cycle.
Event-triggered logical flow control for comprehensive process integration of multi-step assays on centrifugal microfluidic platforms
Authors: Kinahan David J. , Kearney Sinéad M. , Dimov Nikolay , Glynn Macdara T. , Ducrée Jens
Published: April 2014

Dissolvable-film based centrifugo-pneumatic valving enables event-triggered flow control and parallelization of complex, multi-step, multi-reagent bioassays.
A mechanistic study on the α-N-acetylgalactosaminidase from E. meningosepticum: a family 109 glycoside hydrolase
Authors: Chakladar Saswati , Shamsi Kazem Abadi Saeideh , Bennet Andrew J.
Published: April 2014

Studies on the mechanism of action used by a GH109 enzyme.
Altered desferrioxamine-mediated iron utilization is a common trait of bald mutants of Streptomyces coelicolor
Authors: Lambert Stéphany , Traxler Matthew F. , Craig Matthias , Maciejewska Marta , Ongena Marc , van Wezel Gilles P. , Kolter Roberto , Rigali Sébastien
Published: April 2014

We reveal here that altered siderophore production/uptake is a novel phenotypic marker of mutants ofS. coelicolorunable to sporulate. Our study further strengthens the role of iron in triggering morphogenesis of antibiotic-producingStreptomyces.
Glucosamine modified near-infrared cyanine as a sensitive colorimetric fluorescent chemosensor for aspartic and glutamic acid and its applications
Authors: Zhao Xu , Wei Ruisong , Chen Ligong , Jin Di , Yan Xilong
Published: April 2014

A near-infrared colorimetric fluorescent chemosensor has been developed and successfully applied to Glu and Asp imaging in living cells.
Scaffolded multiple cyclic peptide libraries for protein mimics by native chemical ligation
Authors: van de Langemheen H. , van Hoeke M. , Quarles van Ufford H. C. , Kruijtzer J. A. W. , Liskamp R. M. J.
Published: April 2014

The accessibility to collections, libraries and arrays of cyclic peptides is increasingly important since cyclic peptides may provide better mimics of the loop-like structures ubiquitously present in and – especially – on the surface of proteins.
Low-temperature oxidation of particulate matter using ozone
Authors: Itoh Yoshihiko , Sakakibara Yuji , Shinjoh Hirofumi
Published: April 2014

Oxidation of particulate matter (PM) was investigated using ozone. PM was effectively oxidized by ozone below 573 K.
Size control and biological properties of monodispersed mesoporous bioactive glass sub-micron spheres
Authors: Hu Qing , Li Yuli , Miao Guohou , Zhao Naru , Chen Xiaofeng
Published: April 2014

Monodispersed mesoporous bioactive glass sub-micron spheres with a controllable size and good biocompatibility were fabricated by an improved sol–gel method.
Molecular self-assembly guides the fabrication of peptide nanofiber scaffolds for nerve repair
Authors: He Bin , Yuan Xiao , Jiang Dianming
Published: April 2014

The particular features render ionic self-complementary peptide-formed and peptide amphiphile-formed nanofiber scaffolds to be compelling biomaterial substrates for nerve repair.
Single-LED solar simulator for amorphous Si and dye-sensitized solar cells
Authors: Nakajima Tomohiko , Shinoda Kentaro , Tsuchiya Tetsuo
Published: April 2014

Smallest sun: single LED solar simulator that shows high quality simulated solar spectrum in accordance with the AM1.5G standard has been developed.
RuSe/reduced graphene oxide: an efficient electrocatalyst for VO2+/VO2+ redox couples in vanadium redox flow batteries
Authors: Han Pengxian , Wang Xiaogang , Zhang Lixue , Wang Tianshi , Yao Jianhua , Huang Changshui , Gu Lin , Cui Guanglei
Published: April 2014

Selenium modified ruthenium/reduced graphene oxide (RuSe/rGO) exhibits excellent electrocatalytic performance towards VO2+/VO2+ redox couples in vanadium redox flow batteries.
Ammonia borane–metal alanate composites: hydrogen desorption properties and decomposition processes
Authors: Nakagawa Yuki , Ikarashi Yudai , Isobe Shigehito , Hino Satoshi , Ohnuki Somei
Published: April 2014

Mixed-metal amidoborane would play an important role in suppressing the emission of by-product gases from AB–MAlH4 (M = Na, Li) composites.
Binding of hemoglobin to ultrafine carbon nanoparticles: a spectroscopic insight into a major health hazard
Authors: Banerji Biswadip , Pramanik Sumit Kumar , Pal Uttam , Chandra Maiti Nakul
Published: April 2014

Binding of hemoglobin and myoglobin to carbon nanoparticles.
Self-structure formation in polyadenylic acid by small molecules: new insights from the binding of planar dyes thionine and toluidine blue O
Authors: Paul Puja , Suresh Kumar Gopinatha
Published: April 2014

Thionine and toluidine blue targeting poly(A).
How dimensionality changes the anomalous behavior and melting scenario of a core-softened potential system?
Authors: Dudalov D. E. , Fomin Y. D. , Tsiok E. N. , Ryzhov V. N.
Published: April 2014

We present a computer simulation study of the phase diagram and anomalous behavior of two-dimensional (2D) and three-dimensional (3D) classical particles repelling each other through an isotropic core-softened potential.
Effects of hydrophobic interaction strength on the self-assembled structures of model peptides
Authors: Mu Yan , Yu Meng
Published: April 2014

Stable and ordered self-assembled peptide nanostructures are formed as a result of cooperative effects of various relatively weak intermolecular interactions.
Foam clogging
Authors: Rouyer F. , Haffner B. , Louvet N. , Khidas Y. , Pitois O.
Published: April 2014

To what extent are aqueous foams prone to clogging?
Manufacturing and characterization of Magnéli phase conductive fibres
Authors: Adamaki V. , Clemens F. , Ragulis P. , Pennock S. R. , Taylor J. , Bowen C. R.
Published: April 2014

This paper reports a simple and inexpensive method for preparing fine scale (Ø 260 μm) and high-density Magnéli phase (TinO2n−1) conductive ceramic fibres.
Efficient carrier transport in halide perovskites: theoretical perspectives
Authors: Du M. H.
Published: April 2014

Density functional calculations of electronic structure, dielectric properties, and defect properties of CH3NH3PbI3 explain the exceptionally good transport properties in CH3NH3PbI3 (a very promising solar cell material).
Preparation of PEG-modified PAMAM dendrimers having a gold nanorod core and their application to photothermal therapy
Authors: Li Xiaojie , Takeda Keishi , Yuba Eiji , Harada Atsushi , Kono Kenji
Published: April 2014

A new type of hybrid dendrimer consisting of a gold nanorod core and polyethylene glycol-modified polyamidoamine dendrons was developed for biomedical applications such as photothermal therapy.
The solid-state electrochemical reduction process of magnetite in Li batteries: in situ magnetic measurements toward electrochemical magnets
Authors: Yamada Tetsuya , Morita Kantaro , Kume Keita , Yoshikawa Hirofumi , Awaga Kunio
Published: April 2014

A comprehensive study on the solid-state electrochemical reduction process of magnetite (Fe3O4) nanoparticles in Li batteries reveals a rechargeable battery performance and a controllable change in magnetization.
The expression of the tumour suppressor HBP1 is down-regulated by growth factors via the PI3K/PKB/FOXO pathway
Authors: Coomans de Brachène Alexandra , Bollaert Emeline , Eijkelenboom Astrid , de Rocca Serra Audrey , van der Vos Kristan E. , Burgering Boudewijn M. T. , Coffer Paul J. , Essaghir Ahmed , Demoulin Jean-Baptiste
Published: April 2014

Growth factors inactivate the FOXO (forkhead box O) transcription factors through PI3K (phosphoinositide 3-kinase) and PKB (protein kinase B). By comparing microarray data from multiple model systems, we identified HBP1 (high-mobility group-box protein 1) as a novel downstream target of this pathway. HBP1 mRNA was down-regulated by PDGF (platelet-derived growth factor), FGF (fibroblast growth factor), PI3K and PKB, whereas it was up-regulated by FOXO factors. This observation was confirmed in human and murine fibroblasts as well as in cell lines derived from leukaemia, breast adenocarcinoma and colon carcinoma. Bioinformatics analysis led to the identification of a conserved consensus FOXO-binding site in the HBP1 promoter. By luciferase activity assay and ChIP, we demonstrated that FOXO bound to this site and regulated the HBP1 promoter activity in a PI3K-dependent manner. Silencing of HBP1 by shRNA increased the proliferation of human fibroblasts in response to growth factors, suggesting that HBP1 limits cell growth. Finally, by analysing a transcriptomics dataset from The Cancer Genome Atlas, we observed that HBP1 expression was lower in breast tumours that had lost FOXO expression. In conclusion, HBP1 is a novel target of the PI3K/FOXO pathway and controls cell proliferation in response to growth factors.
Some new bounds for binary multiple burst‐correcting codes
Authors: García Villalba L.J. , Sandoval Orozco A.L. , Blaum M.
Published: April 2014

Some new bounds are presented for multiple burst‐correcting codes that extend the previously known bounds, such as the Reiger and the Gallager bounds. It is shown that both the new bounds coincide for block codes. For some values, the new bounds improve the extended volume bound.
Synchronization in a coupled architecture of microelectromechanical oscillators
Authors: Agrawal Deepak K. , Woodhouse Jim , Seshia Ashwin A.
Published: April 2014

There has been much recent interest in engineering the phenomenon of synchronization in coupled micro-/nano-scale oscillators for applications ranging from precision time and frequency references to new approaches to information processing. This paper presents descriptive modelling detail and further experimental validation of the phenomenon of mutual synchronization in coupled MEMS oscillators building upon recent experimental validation of this concept by the present authors. In particular, the underlying dependence of the observation of synchronization on system parameters is studied through numerical and analytical modelling while considering essential nonlinearities in both the resonator and circuit domain. Experimental results demonstrating synchronized response are elaborated based on the realization of electrically coupled MEMS resonator based square-wave oscillators. The experimental results on frequency entrainment are found to be in general agreement with results obtained through analytical modeling and numerical simulation. The concept presented here is scalable and could be used to investigate the dynamics of large-arrays of coupled MEMS oscillators.
Describing long-range charge-separation processes with subsystem density-functional theory
Authors: Solovyeva Alisa , Pavanello Michele , Neugebauer Johannes
Published: April 2014

Long-range charge-transfer processes in extended systems are difficult to describe with quantum chemical methods. In particular, cost-effective (non-hybrid) approximations within time-dependent density functional theory (DFT) are not applicable unless special precautions are taken. Here, we show that the efficient subsystem DFT can be employed as a constrained DFT variant to describe the energetics of long-range charge-separation processes. A formal analysis of the energy components in subsystem DFT for such excitation energies is presented, which demonstrates that both the distance dependence and the long-range limit are correctly described. In addition, electronic couplings for these processes as needed for rate constants in Marcus theory can be obtained from this method. It is shown that the electronic structure of charge-separated states constructed by a positively charged subsystem interacting with a negatively charged one is difficult to converge — charge leaking from the negative subsystem to the positive one can occur. This problem is related to the delocalization error in DFT and can be overcome with asymptotically correct exchange–correlation (XC) potentials or XC potentials including a sufficiently large amount of exact exchange. We also outline an approximate way to obtain charge-transfer couplings between locally excited and charge-separated states.
Correlation between thermodynamic anomalies and pathways of ice nucleation in supercooled water
Authors: Singh Rakesh S. , Bagchi Biman
Published: April 2014

The well-known classical nucleation theory (CNT) for the free energy barrier towards formation of a nucleus of critical size of the new stable phase within the parent metastable phase fails to take into account the influence of other metastable phases having density/order intermediate between the parent metastable phase and the final stable phase. This lacuna can be more serious than capillary approximation or spherical shape assumption made in CNT. This issue is particularly significant in ice nucleation because liquid water shows rich phase diagram consisting of two (high and low density) liquid phases in supercooled state. The explanations of thermodynamic and dynamic anomalies of supercooled water often invoke the possible influence of a liquid-liquid transition between two metastable liquid phases. To investigate both the role of thermodynamic anomalies and presence of distinct metastable liquid phases in supercooled water on ice nucleation, we employ density functional theoretical approach to find nucleation free energy barrier in different regions of phase diagram. The theory makes a number of striking predictions, such as a dramatic lowering of nucleation barrier due to presence of a metastable intermediate phase and crossover in the dependence of free energy barrier on temperature near liquid-liquid critical point. These predictions can be tested by computer simulations as well as by controlled experiments.
Do Agn (up to n = 8) clusters retain their identity on graphite? Insights from first-principles calculations including dispersion interactions
Authors: Singh Akansha , Majumder Chiranjib , Sen Prasenjit
Published: April 2014

Adsorption of pre-formed Agn clusters for n = 1 − 8 on a graphite substrate is studied within the density functional theory employing the vdW-DF2 functional to treat dispersion interactions. Top sites above surface layer carbon atoms turn out to be most favorable for a Ag adatom, in agreement with experimental observations. The same feature is observed for clusters of almost all sizes which have the lowest energies when the Ag atoms are positioned over top sites. Most gas phase isomers retain their structures over the substrate, though a couple of them undergo significant distortions. Energetics of the adsorption can be understood in terms of a competition between energy cost of disturbing Ag–Ag bonds in the cluster and energy gain from Ag–C interactions at the surface. Ag3 turns out to be an exceptional candidate in this regard that undergoes significant structural distortion and has only two of the Ag atoms close to surface C atoms in its lowest energy structure.
Pseudo-Z symmetric space-times
Authors: Mantica Carlo Alberto , Suh Young Jin
Published: April 2014

In this paper, we investigate Pseudo-Z symmetric space-time manifolds. First, we deal with elementary properties showing that the associated form Ak is closed: in the case the Ricci tensor results to be Weyl compatible. This notion was recently introduced by one of the present authors. The consequences of the Weyl compatibility on the magnetic part of the Weyl tensor are pointed out. This determines the Petrov types of such space times. Finally, we investigate some interesting properties of (PZS)4 space-time; in particular, we take into consideration perfect fluid and scalar field space-time, and interesting properties are pointed out, including the Petrov classification. In the case of scalar field space-time, it is shown that the scalar field satisfies a generalized eikonal equation. Further, it is shown that the integral curves of the gradient field are geodesics. A classical method to find a general integral is presented.
Theoretical modeling of UV-Vis absorption and emission spectra in liquid state systems including vibrational and conformational effects: Explicit treatment of the vibronic transitions
Authors: D’Abramo Marco , Aschi Massimiliano , Amadei Andrea
Published: April 2014

Here, we extend a recently introduced theoretical-computational procedure [M. D’Alessandro, M. Aschi, C. Mazzuca, A. Palleschi, and A. Amadei, J. Chem. Phys. 139, 114102 (2013)] to include quantum vibrational transitions in modelling electronic spectra of atomic molecular systems in condensed phase. The method is based on the combination of Molecular Dynamics simulations and quantum chemical calculations within the Perturbed Matrix Method approach. The main aim of the presented approach is to reproduce as much as possible the spectral line shape which results from a subtle combination of environmental and intrinsic (chromophore) mechanical-dynamical features. As a case study, we were able to model the low energy UV-vis transitions of pyrene in liquid acetonitrile in good agreement with the experimental data.
Charge transport through split photoelectrodes in dye-sensitized solar cells
Authors: Fakharuddin Azhar , Ahmed Irfan , Khalidin Zulkeflee , Yusoff Mashitah M. , Jose Rajan
Published: April 2014

Charge transport and recombination are relatively ignored parameters while upscaling dye-sensitized solar cells (DSCs). Enhanced photovoltaic parameters are anticipated by merely widening the devices physical dimensions, viz., thickness and area as evident from the device design adopted in reported large area DSCs. These strip designs lead to ≤50% loss in photocurrent compared to the high efficiency lab scale devices. Herein, we report that the key to achieving higher current density (JSC) is optimized diffusion volume rather than the increased photoelectrode area because kinetics of the devices is strongly influenced by the varied choices of diffusion pathways upon increasing the electrode area. For a given electrode area and thickness, we altered the photoelectrode design by splitting the electrode into multiple fractions to restrict the electron diffusion pathways. We observed a correlation between the device physical dimensions and its charge collection efficiency via current-voltage and impedance spectroscopy measurements. The modified electrode designs showed >50% increased JSC due to shorter transport time, higher recombination resistance and enhanced charge collection efficiency compared to the conventional ones despite their similar active volume (∼3.36 × 10−4 cm3). A detailed charge transport characteristic of the split devices and their comparison with single electrode configuration is described in this article.
Three-dimensional linear peeling-ballooning theory in magnetic fusion devices
Authors: Weyens T. , Sánchez R. , García L. , Loarte A. , Huijsmans G.
Published: April 2014

Ideal magnetohydrodynamics theory is extended to fully 3D magnetic configurations to investigate the linear stability of intermediate to high n peeling-ballooning modes, with n the toroidal mode number. These are thought to be important for the behavior of edge localized modes and for the limit of the size of the pedestal that governs the high confinement H-mode. The end point of the derivation is a set of coupled second order ordinary differential equations with appropriate boundary conditions that minimize the perturbed energy and that can be solved to find the growth rate of the perturbations. This theory allows of the evaluation of 3D effects on edge plasma stability in tokamaks such as those associated with the toroidal ripple due to the finite number of toroidal field coils, the application of external 3D fields for elm control, local modification of the magnetic field in the vicinity of ferromagnetic components such as the test blanket modules in ITER, etc.
Pressure-induced ferroelastic phase transition in SnO2 from density functional theory
Authors: Yang Lei , Fan Weiliu , Li Yanlu , Wei Lei , Zhao Xian
Published: April 2014

High-pressure ferroelastic transition of rutile- to CaCl2-type SnO2 is investigated within density functional theory and Landau free energy theory. The calculated Landau energy map around the ground state is successfully used to clarify the softening mechanism of B1g mode (order parameter Q) and the coupling mechanism between the soft B1g mode and the soft transverse acoustic (TA) mode (strain ɛ). It is found that the Sn-O-Sn bending induced soft B1g mode effectively slows the excess energy increase caused by bond stretching, while the coupling between the soft B1g mode and the soft TA mode further decreases the energy since the lattice distortion strain ɛ minimizes the SnO6 octahedral distortion. Q induced Landau Gibbs free energy is interpreted as the sum of the bond stretching energy, bending energy, and octahedral distortion energy, while that induced by ɛ is interpreted as the lattice distortion energy.
Gamma-ray flares in the Crab Nebula: A case of relativistic reconnection?
Authors: Cerutti B. , Werner G. R. , Uzdensky D. A. , Begelman M. C.
Published: April 2014

The Crab Nebula was formed after the collapse of a massive star about a thousand years ago, leaving behind a pulsar that inflates a bubble of ultra-relativistic electron-positron pairs permeated with magnetic field. The observation of brief but bright flares of energetic gamma rays suggests that pairs are accelerated to PeV energies within a few days; such rapid acceleration cannot be driven by shocks. Here, it is argued that the flares may be the smoking gun of magnetic dissipation in the Nebula. Using 2D and 3D particle-in-cell simulations, it is shown that the observations are consistent with relativistic magnetic reconnection, where pairs are subject to strong radiative cooling. The Crab flares may highlight the importance of relativistic magnetic reconnection in astrophysical sources.
Magnetization reversal and dynamics in non-interacting NiFe mesoscopic ring arrays
Authors: Kaur M. , Husale S. , Varandani D. , Gupta A. , Senguttuvan T. D. , Mehta B. R. , Budhani R. C.
Published: April 2014

The dynamics of magnetization (M) reversal and relaxation as a function of temperature (T) are reported in three non-interacting NiFe ring arrays having fixed ring outer diameter and varying widths. Additionally, the dependence of M(H) loop on the angle (θ) between magnetic field (H) and the plane of the rings is addressed. The M(H) loops show a double step transition from onion state (OS) to vortex state (VS) at all temperatures (T = 3 to 300 K) and angles (θ = 0 to 90°). The critical reversal fields HC1 (OS to VS) and HC2 (VS to OS) show a pronounced dependence on T, ring width, and θ. Estimation of the transverse and vortex domain wall energies reveals that the latter is favored in the OS. The OS is also the remanent state in the smallest rings and decays with the effective energy scale (U0/T) of 50 and 32 meV/K at 10 and 300 K, respectively. The robust in-plane anisotropy of magnetization of ring assemblies is established by scaling the M(H) with θ.
Amorphous silicon passivated contacts for diffused junction silicon solar cells
Authors: Bullock J. , Yan D. , Wan Y. , Cuevas A. , Demaurex B. , Hessler-Wyser A. , De Wolf S.
Published: April 2014

Carrier recombination at the metal contacts is a major obstacle in the development of high-performance crystalline silicon homojunction solar cells. To address this issue, we insert thin intrinsic hydrogenated amorphous silicon [a-Si:H(i)] passivating films between the dopant-diffused silicon surface and aluminum contacts. We find that with increasing a-Si:H(i) interlayer thickness (from 0 to 16 nm) the recombination loss at metal-contacted phosphorus (n+) and boron (p+) diffused surfaces decreases by factors of ∼25 and ∼10, respectively. Conversely, the contact resistivity increases in both cases before saturating to still acceptable values of ∼ 50 mΩ cm2 for n+ and ∼100 mΩ cm2 for p+ surfaces. Carrier transport towards the contacts likely occurs by a combination of carrier tunneling and aluminum spiking through the a-Si:H(i) layer, as supported by scanning transmission electron microscopy–energy dispersive x-ray maps. We explain the superior contact selectivity obtained on n+ surfaces by more favorable band offsets and capture cross section ratios of recombination centers at the c-Si/a-Si:H(i) interface.
Optimal siting and sizing of unified power flow controller using covariance matrix adapted evolution strategy in grid integrated wind energy conversion systems
Authors: Alamelu S. M. , Baskar S. , Babulal C. K. , Jeyadevi S.
Published: April 2014

This paper discusses the application of covariance matrix adapted evolution strategy (CMAES) algorithm on wind energy conversion systems. CMAES is a class of continuous evolutionary algorithm that generates new population members by sampling from a probability distribution that is constructed during the optimization process. Modified IEEE 14 bus system is considered for simulation purpose. The critical evaluation of maximum loadability of the system is determined. Statistical performance of CMAES algorithm reveals that the best value of maximum loadability is obtained when compared to primal dual interior point method. Even though CMAES takes higher computation time, this method gives the best loadability margin.
Passivation effect on gate-bias stress instability of carbon nanotube thin film transistors
Authors: Won Lee Sang , Suh Dongseok , Young Lee Si , Hee Lee Young
Published: April 2014

A prior requirement of any developed transistor for practical use is the stability test. Random network carbon nanotube-thin film transistor (CNT-TFT) was fabricated on SiO2/Si. Gate bias stress stability was investigated with various passivation layers of HfO2 and Al2O3. Compared to the threshold voltage shift without passivation layer, the measured values in the presence of passivation layers were reduced independent of gate bias polarity except HfO2 under positive gate bias stress (PGBS). Al2O3 capping layer was found to be the best passivation layer to prevent ambient gas adsorption, while gas adsorption on HfO2 layer was unavoidable, inducing surface charges to increase threshold voltage shift in particular for PGBS. This high performance in the gate bias stress test of CNT-TFT even superior to that of amorphous silicon opens potential applications to active TFT industry for soft electronics.
A measurable force driven by an excitonic condensate
Authors: Hakioğlu T. , Özgün Ege , Günay Mehmet
Published: April 2014

Free energy signatures related to the measurement of an emergent force (≈10−9N) due to the exciton condensate (EC) in Double Quantum Wells are predicted and experiments are proposed to measure the effects. The EC-force is attractive and reminiscent of the Casimir force between two perfect metallic plates, but also distinctively different from it by its driving mechanism and dependence on the parameters of the condensate. The proposed experiments are based on a recent experimental work on a driven micromechanical oscillator. Conclusive observations of EC in recent experiments also provide a strong promise for the observation of the EC-force.
Fast discharge in a spherical cavity
Authors: Antsiferov P. S. , Dorokhin L. A.
Published: April 2014

The work is devoted to the study of the plasma, created by a fast discharge in a spherical cavity. The discharge was driven by an inductive storage with plasma erosion opening switch (dI/dt ∼1012 A/s). The plasma was produced in a spherical cavity (alumina, 11 mm diameter). Xe, Ar, and He at the pressure 80 Pa were used as working gases. The time evolution of the spatial structure and of extreme ultraviolet (EUV) spectra of the discharge plasma was studied by means of micro channel plate detector. The discharges with Xe and Ar resulted in the stable appearance of the spherically shaped plasma with the diameter about 1–3 mm. The plasma emission in the EUV region lasts ∼500 ns. The EUV spectrum of Ar discharge at the moment of maximum of the electron temperature Te contains the lines of Ar X (ionization potential 478.7 eV), that indicates a value of Te in the range 50–100 eV. The mechanism of plasma appearance can be the cumulation of the convergent spherical shock wave, generated by fast heat deposition and magnetic pressure in working media near the inner surface of the discharge volume.
Individually addressable multi-chamber electroporation platform with dielectrophoresis and alternating-current-electro-osmosis assisted cell positioning
Authors: Park Sinwook , Bassat Dana Ben , Yossifon Gilad
Published: April 2014

A multi-functional microfluidic platform was fabricated to demonstrate the feasibility of on-chip electroporation integrated with dielectrophoresis (DEP) and alternating-current-electro-osmosis (ACEO) assisted cell/particle manipulation. A spatial gradient of electroporation parameters was generated within a microchamber array and validated using normal human dermal fibroblast (NHDF) cells and red fluorescent protein-expressing human umbilical vein endothelial cells (RFP-HUVECs) with various fluorescent indicators. The edge of the bottom electrode, coinciding with the microchamber entrance, may act as an on-demand gate, functioning under either positive or negative DEP. In addition, at sufficiently low activation frequencies, ACEO vortices can complement the DEP to contribute to a rapid trapping/alignment of particles. As such, results clearly indicate that the microfluidic platform has the potential to achieve high-throughput screening for electroporation with spatial control and uniformity, assisted by DEP and ACEO manipulation/trapping of particles/cells into individual microchambers.
Strain-induced phase transformation under compression in a diamond anvil cell: Simulations of a sample and gasket
Authors: Feng Biao , Levitas Valery I. , Ma Yanzhang
Published: April 2014

Combined high pressure phase transformations (PTs) and plastic flow in a sample within a gasket compressed in diamond anvil cell (DAC) are studied for the first time using finite element method. The key point is that phase transformations are modelled as strain-induced, which involves a completely different kinetic description than for traditional pressure-induced PTs. The model takes into account, contact sliding with Coulomb and plastic friction at the boundaries between the sample, gasket, and anvil. A comprehensive computational study of the effects of the kinetic parameter, ratio of the yield strengths of high and low-pressure phases and the gasket, sample radius, and initial thickness on the PTs and plastic flow is performed. A new sliding mechanism at the contact line between the sample, gasket, and anvil called extrusion-based pseudoslip is revealed, which plays an important part in producing high pressure. Strain-controlled kinetics explains why experimentally determined phase transformation pressure and kinetics (concentration of high pressure phase vs. pressure) differ for different geometries and properties of the gasket and the sample: they provide different plastic strain, which was not measured. Utilization of the gasket changes radial plastic flow toward the center of a sample, which leads to high quasi-homogeneous pressure for some geometries. For transformation to a stronger high pressure phase, plastic strain and concentration of a high-pressure phase are also quasi-homogeneous. This allowed us to suggest a method of determining strain-controlled kinetics from experimentation, which is not possible for weaker and equal-strength high-pressure phases and cases without a gasket. Some experimental phenomena are reproduced and interpreted. Developed methods and obtained results represent essential progress toward the understanding of PTs under compression in the DAC. This will allow one optimal design of experiments and conditions for synthesis of new high pressure phases.
Strain rate dependence of twinning avalanches at high speed impact
Authors: Zhang L. , Salje E. K. H. , Ding X. , Sun J.
Published: April 2014

The molecular dynamics simulation of the yield collapse in ferroelastic and martensitic materials under high strain rates shows power law decays of the yield energy. The energy exponent of the “jerk” distribution during yield does not depend on the strain rate and was found to be close to the mean field value of ε = 1.35. The total yield energy changes dramatically during the crossover between the isothermal regime at low strain rates and the adiabatic regime at high strain rates. The crossover point is found in our simulations at 10−5/phonon time which corresponds to strain rates of approximately 108 1/s. Faster strain rates occur for high speed impact (shock deformation) with no strain absorption by twinning and no thermal equilibration while slightly slower strain rates lead to rate independent yield energies.