bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial crust with Frutexites(?) and iron staining in chalks: Albian–Cenomanian boundary, Hunstanton, UK
Authors: ANDREWS J. E. , KENDALL A. C. , HALL A.
Published: April 2014

New petrographic observations and stable isotope data help reinterpret the complex sedimentology of the Albian–Cenomanian boundary exposed in the famous red and white chalks of the cliff section at Hunstanton in Norfolk, UK. Thin-section analysis of a prominent crust at the top of the Hunstanton Red Chalk Formation reveals fossil microstructures attributable to the microbe Frutexites. These Red Chalk microstructures are less bushy that Frutexites sensu stricto, and poor preservation, in part caused by later diagenetic iron migration, means they are identified only tentatively as Frutexites. Stable oxygen isotope values from the crust are similar to those from early diagenetic nodular chalks immediately below the crust, and to partially altered chalks elsewhere in Norfolk. The δ18O data are interpreted as Albian seafloor depositional values albeit slightly altered by subsequent meteoric diagenesis. The microbial affinities of Frutexites are not yet proven; thus, the presence of Frutexites alone is not diagnostic of either photic zone or deep-water sedimentation. However, the presence of Frutexites(?) suggests that the red colour of the Hunstanton Red Chalk is due, at least in part, to the mediation of iron-fixing microbes in the accumulating chalk sediment at a dysoxic–anoxic interface. Centimetre-scale columnar and nodular structures above the ‘Frutexites crust’ that project upwards into the basal Paradoxica Bed of the overlying Ferriby Chalk Formation are sites of localized syndepositional iron staining. These nodules are not stromatolitic or microbial and are not evidence for deposition in shallow-water or intertidal settings.
LATE-ENTRY-INTO-MOTHERHOOD WOMEN ARE RESPONSIBLE FOR FERTILITY RECUPERATION
Authors: CASTRO RUBÉN
Published: April 2014

In countries where age at parenthood has shifted to older ages, a necessary precondition for fertility recuperation is that women having their first child later in life (after age 30) will also eventually achieve a higher completed fertility, compared with the previous cohorts. This study analysed the changes in age-at-first-child-conditional fertility rates in Western Europe through three birth cohorts (1936–1940, 1946–1950 and 1956–1960). It was found that generations where recuperation is first evident (1956–1960 cohort) are characterized by comparatively higher fertility of late age-at-first-child women. This characteristic is not found in Eastern Europe, where ages at first birth and cohort fertility remained fairly constant across the cohorts analysed.
In vitrocytokines profile and ultrastructural changes of microglia and macrophages following interaction withLeishmania
Authors: RAMOS PATRICIA KARLA SANTOS , BRITO MAYSA DE VASCONCELOS , SILVEIRA FERNANDO TOBIAS , SALGADO CLÁUDIO GUEDES , DE SOUZA WANDERLEY , PICANÇO-DINIZ CRISTOVAM WANDERLEY , PICANÇO-DINIZ JOSÉ ANTONIO JUNIOR
Published: April 2014

In the present study, we assessed morphological changes and cytokine production afterin vitrointeraction with causative agents of American cutaneous leishmaniasis and compared the microglia and macrophage immune responses. Cultures of microglia and macrophages infected with stationary-phase promastigotes ofLeishmania(Viannia)shawi, Leishmania(Viannia)braziliensisorLeishmania(Leishmania)amazonensiswere evaluated 24, 48 and 72 h after interaction. Macrophages only presented the classical phagocytic process while microglia also displayed large cytoplasmic projections similar to the ruffles described in macropinocytosis. In the macrophage cultures, the percentage of infected cells increased over time, in a fashion that was dependent on the parasite species. In contrast, in microglial cells as the culture time progressed, there was a significant reduction in the percentage of infected cells independent of parasite species. Measurements of cytokines in macrophage cultures 48 h after interactions revealed distinct expression patterns for different parasites, whereas in microglial cultures they were similar for allLeishmaniatested species. Taken together, our results suggest that microglia may have a higher phagocytic ability and cytotoxic potential than macrophages for all investigated species. The robust response of microglia against all parasite species may suggest microglia have an important role in the defence against cerebral leishmaniasis.
Neuropsychological deficits in past suicide attempters with varying levels of depression severity
Authors: Keilp J. G. , Beers S. R. , Burke A. K. , Melhem N. M. , Oquendo M. A. , Brent D. A. , Mann J. J.
Published: April 2014

Background

Our previous work identified deficits in interference processing and learning/memory in past suicide attempters who were currently depressed and medication-free. In this study, we extend this work to an independent sample studied at various stages of illness and treatment (mild symptoms, on average) to determine if these deficits in past suicide attempters are evident during a less severe clinical state.

Method

A total of 80 individuals with a past history of major depression and suicide attempt were compared with 81 individuals with a history of major depression and no lifetime suicide attempts on a battery of neurocognitive measures assessing attention, memory, abstract/contingent learning, working memory, language fluency and impulse control.

Results

Past attempters performed more poorly in attention, memory and working memory domains, but also in an estimate of pre-morbid intelligence. After correction for this estimate, tests that had previously distinguished past attempters – a computerized Stroop task and the Buschke Selective Reminding Test – remained significantly worse in attempters. In a secondary analysis, similar differences were found among those with the lowest levels of depression (Hamilton Depression Rating Scale score <10), suggesting that these deficits may be trait markers independent of current symptomatology.

Conclusions

Deficits in interference processing and learning/memory constitute an enduring defect in information processing that may contribute to poor adaptation, other higher-order cognitive impairments and risk for suicidal behavior.
Environmental attitudes associated with large-scale cultural differences, not local environmental conflicts
Authors: GANGAAS KRISTIN E. , KALTENBORN BJØRN P. , ANDREASSEN HARRY P.
Published: April 2014

Species and ecosystems are under constant pressure from a rapidly-growing human population. Human tolerance of carnivores, including the willingness to live in areas with these predators, is key to the success of large carnivore conservation. In the Scandinavian Peninsula, large carnivore populations conflict with human activity; low tolerance among local people may lead to illegal hunting. A survey of 2521 Scandinavian respondents to measure environmental value orientation, using the new environmental paradigm (NEP) scale and attitudes toward large carnivores, revealed attitudes towards the presence of carnivores were not related to carnivore abundance. Nor was there a significant relationship between environmental value orientation and personal experiences with loss of domestic sheep or hunting dogs. Environmental values were mainly explained by country differences; Swedes had a more ecocentric value orientation than Norwegians. Significantly more Norwegians (45 %) than Swedes (19 %) responded that there were too many carnivores in their country. Historic differences in how government is perceived between Norway and Sweden may result in different attitudes towards illegal hunting and towards carnivores. Specifically, Norwegians may hold a more anthropocentric view, based on a suspicion of central authorities, whereas Swedes may hold a more ecocentric view.
Impact of diabetes on clinical presentation and treatment outcome of pulmonary tuberculosis in Beijing
Authors: HONGGUANG C. , MIN L. , SHIWEN J. , FANGHUI G. , SHAOPING H. , TIEJIE G. , NA L. , ZHIGUO Z.
Published: April 2014

Diabetes mellitus (DM) is currently known to be one of the risk factors for pulmonary tuberculosis (PTB) and the proportion of DM in PTB is rising along with the increased prevalence of DM in countries with high PTB burden. This study was designed to explore the impact of DM on clinical presentation and treatment outcome of PTB in China. In an urban setting in Beijing, 1126 PTB patients, 30·6% with positive sputum smear, registered in two PTB dispensaries from January 2010 to December 2011 were screened for DM and were followed up prospectively during PTB treatment. DM was observed in 16·2% of patients with PTB. PTB with DM appeared to be associated with older age and a higher proportion of re-treatment. On presentation, DM was associated with more severe PTB signs with higher proportions of smear positivity [odds ratio (OR) 2·533, 95% confidence interval (CI) 1·779–3·606], cavity (OR 2·253, 95% CI 1·549–3·276) and more symptoms (OR 1·779, 95% CI 1·176–2·690). DM was also associated with non-TB deaths (OR 5·580, 95% CI 2·182–14·270,P < 0·001) and treatment failure (OR 6·696, 95% CI 2·019–22·200,P = 0·002). In Beijing, the findings of this study underlined the need to perform early bi-directional screening programmes and explore the underlying mechanism for different treatment outcomes for PTB with DM.
Exercise-induced cardiac fatigue in low and normal birth weight young black adults
Authors: Chifamba Jephat , Mapfumo Chidochashe , Mawoneke Dorcas W. , Gwaunza Lenon T. , Allen Larry A. , Chinyanga Herbert M.
Published: April 2014

The objective of the study was to compare the change in diastolic function, E/A ratio, in response to prolonged exercise in low birth weight and normal birth weight individuals. Using a case–control study design, 23 students of the University of Zimbabwe College of Health Sciences who had neonatal clinic cards as proof of birth weight were recruited into the study. Measurements of diastolic function, E/A ratio, were obtained using an echocardiogram before and after 75 minutes of exercise. Among the cohort, seven had low birth weight – <2500 g, three female patients and four male patients – and 16 had normal birth weight – six female patients and 10 male patients). The mean age was 20.7±3.3 years. After prolonged exercise for 75 minutes of running on a treadmill, decreases in diastolic function, E/A ratio, were significantly greater in low birth weight than in normal birth weight individuals (0.48±0.27 versus 0.19±0.18 p<0.05, respectively). There was a significant association between low birth weight and exercise-induced cardiac fatigue (the χ2test p<0.05, odds ratio 4.64, 95% confidence interval 1.19–18.1). We conclude that low birth weight is associated with exercise-induced diastolic dysfunction in young adults.
Horner’s syndrome after paediatric cardiac surgery: case report and review of the literature
Authors: Nasser Bana A. , Mesned Abdulrahman , Moazamy Yousry E. , Kabbani Mohamed S.
Published: April 2014

Iatrogenic Horner’s syndrome is a rare complication that can occur after trauma, cervical central line insertion, chest tube insertion, and rarely following adult thoracic and neck surgery, especially in high risk patients with hypertension and diabetes. The majority of cases reported in the literature describe non-iatrogenic Horner’s syndrome in adults as an unusual presentation for cervical tumours or apical lung carcinoma. In children, there are some reports describing acquired Horner’s syndrome following trauma or invasive intervention near the cervical–thoracic area. Less has been written about the incidence of Horner’s syndrome following paediatric cardiac surgery.
Thoracotomy Paraplegia: A Case Report from the PACU
Authors: Huang Tzu H.
Published: April 2014

The aim of this case report is to present the rare yet devastating complication of post-thoracotomy paraplegia and to raise awareness of the causative factors, as well as to discuss the nursing observation for prompt and effective clinical management in order to achieve successful healthcare outcomes. This case was secondary to the use of haemostatic agents during thoracotomy, and delayed post-operative identification of complication and management leading to long-term spinal cord impairment. Routine neurologic assessment focusing on movement and sensation of the extremities is recommended post-operatively to detect the potential complications as early as possible.
Why Errors in Alibis Are Not Necessarily Evidence of Guilt
Authors: Strange Deryn , Dysart Jennifer , Loftus Elizabeth F.
Published: April 2014

Laypeople, police, and prosecutors tend to believe that a suspect’s alibi, if truthful, should remain consistent over time (see Burke, Turtle, & Olson, 2007 ; Culhane & Hosch 2012 ; Dysart & Strange, 2012 ). However, there is no empirical evidence to support this assumption. We investigated (a) whether some features of an alibi – such as what was happening, who with, where, and for how long – are more likely to produce errors than others; and (b) whether consistency in alibi stories is correlated with particular phenomenological characteristics of the alibi such as a person’s confidence and sense of reliving the event. We asked participants to imagine they were suspected of a crime and to provide their truthful alibi for an afternoon 3 weeks prior and to complete questions regarding the phenomenological characteristics of their memory. We also asked participants to locate evidence of their actual whereabouts for the critical period. Participants returned a week later, presented their evidence, re-told their alibi, and re-rated the phenomenological characteristics of the alibi. Our results revealed that participants were largely inconsistent across all aspects of their alibi, but there was variability across the different features. In addition, those who were inconsistent were less confident, recollected the time period in less detail and less vividly, and were less likely to claim to remember the time period. We conclude that inconsistencies are a normal byproduct of an imperfect memory system and thus should not necessarily arouse suspicion that a suspect is lying.
Prospective Memory in Complex Sociotechnical Systems
Authors: Grundgeiger Tobias , Sanderson Penelope M. , Key Dismukes R.
Published: April 2014

An important cognitive function is the ability to remember to execute future tasks, a capability known as prospective memory (PM). Workers in complex sociotechnical systems such as healthcare and aviation face many PM challenges and forgetting tasks can have severe consequences. Although researchers have made progress in understanding how individuals remember future tasks, system-level support for PM has seldom been addressed. In the present paper, we briefly review PM research in healthcare and aviation, focusing on naturalistic studies using expert workers, and we present the concept of distributed prospective memory, which incorporates the interaction between the environment and the individual when future tasks must be remembered. PM in sociotechnical settings is a complex process involving human and nonhuman agents. Therefore, a systems approach is needed to fully understand PM processes, thus supporting workers and eventually minimizing errors and increasing safety.
Neural Stem Cell Protects Aged Rat Brain from Ischemia–Reperfusion Injury through Neurogenesis and Angiogenesis
Authors: Tang Yaohui , Wang Jixian , Lin Xiaojie , Wang Liuqing , Shao Bei , Jin Kunlin , Wang Yongting , Yang Guo-Yuan
Published: April 2014

Neural stem cells (NSCs) show therapeutic potential for ischemia in young-adult animals. However, the effect of aging on NSC therapy is largely unknown. In this work, NSCs were transplanted into aged (24-month-old) and young-adult (3-month-old) rats at 1 day after stroke. Infarct volume and neurobehavioral outcomes were examined. The number of differentiated NSCs was compared in aged and young-adult ischemic rats and angiogenesis and neurogenesis were also determined. We found that aged rats developed larger infarcts than young-adult rats after ischemia ( P<0.05). The neurobehavioral outcome was also worse for aged rats comparing with young-adult rats. Brain infarction and neurologic deficits were attenuated after NSC transplantation in both aged and young-adult rats. The number of survived NSCs in aged rats was similar to that of the young-adult rats ( P>0.05) and most of them were differentiated into glial fibrillary acidic protein+ (GFAP+) cells. More importantly, angiogenesis and neurogenesis were greatly enhanced in both aged and young-adult rats after transplantation compared with phosphate-buffered saline (PBS) control ( P<0.05), accompanied by increased expression of vascular endothelial growth factor (VEGF). Our results showed that NSC therapy reduced ischemic brain injury, along with increased angiogenesis and neurogenesis in aged rats, suggesting that aging-related microenvironment does not preclude a beneficial response to NSCs transplantation during cerebral ischemia.
Radiosynthesis and Validation of 18F-FP-CMT, a Phenyltropane with Superior Properties for Imaging the Dopamine Transporter in Living Brain
Authors: Cumming Paul , Maschauer Simone , Riss Patrick J , Tschammer Nuska , Fehler Stefanie K , Heinrich Markus R , Kuwert Torsten , Prante Olaf
Published: April 2014

To date there is no validated, 18F-labeled dopamine transporter (DAT) radiotracer with a rapid kinetic profile suitable for preclinical small-animal positron emission tomography (PET) studies in rodent models of human basal ganglia disease. Herein we report radiosynthesis and validation of the phenyltropane 18F-FP-CMT. Dynamic PET recordings were obtained for 18F-FP-CMT in six untreated rats, and six rats pretreated with the high-affinity DAT ligand GBR 12909; mean parametric maps of binding potential ( BPND) relative to the cerebellum reference region, and maps of total distribution volume ( VT) relative to the metabolite-corrected arterial input were produced. 18F-FP-CMT BPND maps showed peak values of ˜4 in the striatum, versus ˜0.4 in the vicinity of the substantia nigra. Successive truncation of the PET recordings indicated that stable BPND estimates could be obtained with recordings lasting only 45 minutes, reflecting rapid kinetics of 18F-FP-CMT. Pretreatment with GBR 12909 reduced the striatal binding by 72% to 76%. High-performance liquid chromatography analysis revealed rapid metabolism of 18F-FP-CMT to a single, non-brain penetrant hydrophilic metabolite. Total distribution of volume calculated relative to the metabolite-corrected arterial input was 4.4 mL/g in the cerebellum. The pharmacological selectivity of 18F-FP-CMT, rapid kinetic profile, and lack of problematic metabolites constitute optimal properties for quantitation of DAT in rat, and may also predict applicability in human PET studies.
Reduced growth and proliferation dynamics of nasal epithelial stem/progenitor cells in nasal polyps in vitro
Authors: Yu Xue Min , Li Chun Wei , Chao Siew Shuen , Li Ying Ying , Yan Yan , Zhao Xue Ning , Yu Feng Gang , Liu Jing , Shen Liang , Pan Xin Liang , Shi Li , Wang De Yun
Published: April 2014

Basal cells in nasal epithelium have stemness/progenitor characters and play essential roles in the epithelial remodeling in nasal polyps (NP). We investigate whether the human nasal epithelial stem/progenitor cells (hNESPCs) from patients with NP are inherently distinct from those obtained from healthy controls. Epithelial basal cells were isolated and cultured for four passages from NP tissues and control nasal mucosa. hNESPCs from controls were stained positively with stem cell marker p63 and KRT5 and presented a consistent high Ki67 expression level over four passages. In contrast, hNESPCs from NP patients showed: i). a reduced growth and proliferation rate at each passage by evaluating colony-forming efficiency and doubling time; ii). a lower percentage of Ki67+ cells among p63+ cells in the colonies in late passages, which was also confirmed by immunostaining in the NP tissues. Thus reduced growth/proliferation dynamics in hNESPCs from NP could be an important pathological phenomenon in NP development.
Synthesis, crystal structure, and cytotoxic activity of novel cyclic systems in [1,2,4]thiadiazolo[2,3-a]pyridine benzamide derivatives and their copper(ii) complexes
Authors: Adhami Forogh , Safavi Maliheh , Ehsani Maryam , Ardestani Sussan K. , Emmerling Franziska , Simyari Farzaneh
Published: April 2014

Novel Cu2+complexes with a square planar structure synthesized from benzamide derivatives showed cytotoxic activity against different human cancer cell lines.
Computational delineation of tyrosyl-substrate recognition and catalytic landscapes by the epidermal growth factor receptor tyrosine kinase domain
Authors: Liu Yingting , Radhakrishnan Ravi
Published: April 2014

Computational delineation of the binding modes of tyrosyl substrate recognition by the epidermal growth factor receptor (EGFR) tyrosine kinase domain (TKD) and subsequent phosphoryl transfer.
Bis-triazologlycolipid mimetics – low molecular weight organogelators
Authors: Hemamalini Arasappan , Mohan Das Thangamuthu
Published: April 2014

A facile regioselective synthesis of bis-triazologlycolipids, a class of organogelators, has been accomplished by “Click reaction”. The morphology and self-assembly of the gelators were examined by FESEM and HRTEM analysis.
Mesoporous carbon material co-doped with nitrogen and iron (Fe–N–C): high-performance cathode catalyst for oxygen reduction reaction in alkaline electrolyte
Authors: Yan Xiang-Hui , Xu Bo-Qing
Published: April 2014

An unprecedented ordered mesoporous carbon material co-doped with nitrogen and iron shows high activity for ORR catalysis in alkaline electrolyte.
A water-soluble sulfonate-BODIPY based fluorescent probe for selective detection of HOCl/OCl−in aqueous media
Authors: Kim Jiyoung , Kim Youngmi
Published: April 2014

A water-soluble sulfonate-BODIPY dye1was developed for the selective detection of HOCl/OCl−in aqueous buffer solution. The probe, which displays extremely weak fluorescence owing to efficient photoinduced electron transfer (PeT) from the pendant catechol donor, responds to HOCl/OCl−through a dramatic enhancement of its fluorescence intensity.
Depletion region effect of highly efficient hole conductor free CH3NH3PbI3perovskite solar cells
Authors: Aharon Sigalit , Gamliel Shany , Cohen Bat El , Etgar Lioz
Published: April 2014

The performance of hole conductor free perovskite solar cells is well dependent on the depletion region, achieving strikingly 10.8% efficiency.
Targeting cytotoxicity and tubulin polymerization by metal–carbene complexes on a purine tautomer platform
Authors: Khanna Shruti , Jana Batakrishna , Saha Abhijit , Kurkute Prashant , Ghosh Surajit , Verma Sandeep
Published: April 2014

This communication describes the synthesis, structural investigation and tubulin binding of purine rare imino tautomer based Ag(i) and Hg(ii)–carbene complexes. These complexes exhibit cytotoxicity through tubulin interaction by binding to a site close to the GTP binding site.
Difference in production routes of water-soluble organic carbon in PM2.5observed during non-biomass and biomass burning periods in Gwangju, Korea
Authors: Yu Geun-Hye , Cho Sung-Yong , Bae Min-Suk , Park Seung-Shik
Published: April 2014

Water-soluble organic carbon observed during the non-biomass burning period was mainly attributed to secondary organic aerosol.
Signal to noise considerations for single crystal femtosecond time resolved crystallography of the Photoactive Yellow Protein
Authors: van Thor Jasper J. , Warren Mark M. , Lincoln Craig N. , Chollet Matthieu , Lemke Henrik Till , Fritz David M. , Schmidt Marius , Tenboer Jason , Ren Zhong , Srajer Vukica , Moffat Keith , Graber Tim
Published: April 2014

Femtosecond time resolved pump–probe protein X-ray crystallography requires highly accurate measurements of the photoinduced structure factor amplitude differences. In the case of femtosecond photolysis of single P63crystals of the Photoactive Yellow Protein, it is shown that photochemical dynamics place a considerable restraint on the achievable time resolution due to the requirement to stretch and add second order dispersion in order to generate threshold concentration levels in the interaction region. Here, we report on using a ‘quasi-cw’ approach to use the rotation method with monochromatic radiation and 2 eV bandwidth at 9.465 keV at the Linac Coherent Light Source operated in SASE mode. A source of significant Bragg reflection intensity noise is identified from the combination of mode structure and jitter with very small mosaic spread of the crystals and very low convergence of the XFEL source. The accuracy with which the three dimensional reflection is approximated by the ‘quasi-cw’ rotation method with the pulsed source is modelled from the experimentally collected X-ray pulse intensities together with the measured rocking curves. This model is extended to predict merging statistics for recently demonstrated self seeded mode generated pulse train with improved stability, in addition to extrapolating to single crystal experiments with increased mosaic spread. The results show that the noise level can be adequately modelled in this manner, indicating that the large intensity fluctuations dominate the merged signal-to-noise (I/σI) value. Furthermore, these results predict that using the self seeded mode together with more mosaic crystals, sufficient accuracy may be obtained in order to resolve typical photoinduced structure factor amplitude differences, as taken from representative synchrotron results.
Correlations in distribution and concentration of calcium, copper and iron with zinc in isolated extracellular deposits associated with age-related macular degeneration
Authors: Flinn Jane M. , Kakalec Peter , Tappero Ryan , Jones Blair , Lengyel Imre
Published: April 2014

Examining the relationship between zinc, calcium, iron and copper in isolated sub-RPE deposits highlighted the diverse role these metals might play in conditions like age-related macular degeneration.
Anisotropic thermal conductivity of graphene wrinkles
Authors: Wang C. , Liu Y. , Li L. , Tan H.
Published: April 2014

Wrinkle-induced anisotropic thermal conductivity of graphene and its physical nature.
Superdirective dielectric nanoantennas
Authors: Krasnok Alexander E. , Simovski Constantin R. , Belov Pavel A. , Kivshar Yuri S.
Published: April 2014

We introduce the novel concept of superdirective nanoantennas based on the excitation of higher-order magnetic multipole moments in subwavelength dielectric nanoparticles.
Polystyrene with hydrophobic end groups: synthesis, kinetics, interfacial activity, and self-assemblies templated by breath figures
Authors: Zhu Liang-Wei , Wu Bai-Heng , Wan Ling-Shu , Xu Zhi-Kang
Published: April 2014

Polystyrenes with hydrophobic end groups are synthesized from a series of alkyl or fluorinated ATRP initiators to fine-tune the surface morphologies of honeycomb films prepared by the breath figure method.
Thermoresponsive properties of 3-, 4-, 6-, and 12-armed star-shaped poly[2-(dimethylamino)ethyl methacrylate]s prepared by core-first group transfer polymerization
Authors: Kikuchi Seiya , Chen Yougen , Fuchise Keita , Takada Kenji , Kitakado Junsuke , Sato Shin-ichiro , Satoh Toshifumi , Kakuchi Toyoji
Published: April 2014

The thermoresponsive behavior of a variety of star-shaped poly[2-(dimethylamino)ethyl methacrylate]s was intensively investigated by evaluating the effect of mass concentration in aqueous solution, molecular weight, or arm number of the polymers on their cloud points.
Metal phosphonate hybrid materials: from densely layered to hierarchically nanoporous structures
Authors: Zhu Yun-Pei , Ma Tian-Yi , Liu Ya-Lu , Ren Tie-Zhen , Yuan Zhong-Yong
Published: April 2014

Inorganic–organic metal phosphonate hybrid materials with great diversity in structure and properties exhibit application potential in various fields.
Polymer based nanoformulation of methylglyoxal as an antimicrobial agent: efficacy against resistant bacteria
Authors: Ghosh Srabanti , Chakraborty Prabal , Saha Partha , Acharya Somobrata , Ray Manju
Published: April 2014

Functionalized polymer conjugated nanoformulations of methylglyoxal demonstrated broad-spectrum antimicrobial activity, leading to new generation antimicrobial agents and minimizing the environment risks.
Facile preparation of graphene/Fe3O4/TiO2 multifunctional composite for highly selective and sensitive enrichment of phosphopeptides
Authors: Liang Yulu , He Xiwen , Chen Langxing , Zhang Yukui
Published: April 2014

A novel multifunctional graphene/Fe3O4/TiO2 magnetic composite with excellent hydrophilicity and biological compatibility was synthesized and exhibited selective capture, fast magnetic isolation and sensitive analysis of low-abundance phosphopeptides from complex biosamples.
Electronic structure engineering in chemically modified ultrathin ZnO nanofilms via a built-in heterointerface
Authors: Guo Hongyan , Lu Ning , Dai Jun , Zeng Xiao Cheng , Wu Xiaojun , Yang Jinlong
Published: April 2014

The electronic properties of chemically modified ZnO ultrathin films with a built-in heterointerface are investigated on the basis of first-principles calculations.
Copper catalyzed Heck-like cyclizations of oxime esters
Authors: Faulkner Adele , Race Nicholas J. , Scott James S. , Bower John F.
Published: April 2014

Copper catalyzed Heck-like cyclizations of oxime esters are described. This new protocol is an effective alternative to Pd-based systems and highlights the value of replacing precious metal catalysts with cheaper and more sustainable variants.
Na3V2(PO4)3@C core–shell nanocomposites for rechargeable sodium-ion batteries
Authors: Duan Wenchao , Zhu Zhiqiang , Li Hao , Hu Zhe , Zhang Kai , Cheng Fangyi , Chen Jun
Published: April 2014

Na3V2(PO4)3@C core–shell nanocomposites were synthesized and applied as electrode materials in rechargeable sodium batteries, showing remarkable rate capability and cyclability.
Self-assembly of graphene oxide aerogels by layered double hydroxides cross-linking and their application in water purification
Authors: Fang Qile , Chen Baoliang
Published: April 2014

3D macrostructural aerogels were synthesized based on the self-assembly of graphene oxide and LDHs, which exhibited excellent hydrophilicity, structural stability, and superior adsorption properties in water purification.
Importance of open, heteroatom-decorated edges in chemically doped-graphene for supercapacitor applications
Authors: Fujisawa Kazunori , Cruz-Silva Rodolfo , Yang Kap-Seung , Kim Yoong Ahm , Hayashi Takuya , Endo Morinobu , Terrones Mauricio , Dresselhaus Mildred S.
Published: April 2014

We demonstrated the importance of open, heteroatom-decorated open edges in graphene-based supercapacitor applications.
Facile synthesis of titanium nitride nanowires on carbon fabric for flexible and high-rate lithium ion batteries
Authors: Balogun Muhammad-Sadeeq , Yu Minghao , Li Cheng , Zhai Teng , Liu Yi , Lu Xihong , Tong Yexiang
Published: April 2014

We demonstrate the good performance of TiN nanowires as anodes for lithium-ion batteries.
Nanoindentation of NiAl and Ni3Al crystals on (100), (110), and (111) surfaces: A molecular dynamics study
Authors: Seymour Richard , Hemeryck Anne , Nomura Ken-ichi , Wang Weiqiang , Kalia Rajiv K. , Nakano Aiichiro , Vashishta Priya
Published: April 2014

Molecular dynamics simulations were performed to study the nanoindentation of NiAl and Ni3Al crystals on three surfaces: (100), (110), and (111). The calculated load-displacement curves show discrete drops at certain indentation depths, indicating dislocation bursts during indentation. The hardness values for the two materials were found to depend significantly on the indented crystallographic plane: the (100) surface is the softest for NiAl and the hardest for Ni3Al. We also found distinctive deformation activities in the subsurface region in Ni3Al crystals, while dislocation loops propagate deep into the substrate in NiAl systems.
Dielectric spectra broadening as a signature for dipole-matrix interaction. IV. Water in amino acids solutions
Authors: Levy Evgeniya , Cerveny Silvina , Ermolina Irina , Puzenko Alexander , Feldman Yuri
Published: April 2014

In this paper, the fourth one of our series on the dielectric spectrum symmetrical broadening of water, we consider amino acid (AA) aqueous solutions. The developed 3D-trajectory is applied here to the variety of zwitterion amino acids representing both the hydrophobic and hydrophilic nature of their residues. The dipole moment of amino acids due to their zwitterion determines their interaction with the solvent and reflects mostly the dipole-matrix interactions described in our Paper I [E. Levy et al., J. Chem. Phys. 136, 114502 (2012)]. It is also shown that in the case of charged AAs at high concentrations, the shape of the 3D trajectory transforms to the pattern typical of the dipole-charge interactions that were described in our Paper III [A. Puzenko et al., J. Chem. Phys. 137, 194502 (2012)].
Collision dynamics of symmetric top molecules: A comparison of the rotationally inelastic scattering of CD3 and ND3 with He
Authors: Tkáč Ondřej , Orr-Ewing Andrew J. , Dagdigian Paul J. , Alexander Millard H. , Onvlee Jolijn , van der Avoird Ad
Published: April 2014

We compare rotationally inelastic scattering of deuterated methyl radicals (CD3) and ammonia (ND3) in collisions with helium using close-coupling quantum-mechanical scattering calculations performed with ab initio potential energy surfaces (PESs). The theoretical methods have been rigorously tested against angle-resolved experimental measurements obtained using crossed molecular beam apparatuses in combination with velocity map imaging [O. Tkáč, A. G. Sage, S. J. Greaves, A. J. Orr-Ewing, P. J. Dagdigian, Q. Ma, and M. H. Alexander, Chem. Sci. 4, 4199 (2013); O. Tkáč, A. K. Saha, J. Onvlee, C.-H. Yang, G. Sarma, C. K. Bishwakarma, S. Y. T. van de Meerakker, A. van der Avoird, D. H. Parker, and A. J. Orr-Ewing, Phys. Chem. Chem. Phys. 16, 477 (2014)]. Common features of the scattering dynamics of these two symmetric top molecules, one closed-shell and the other an open-shell radical, are identified and discussed. Two types of anisotropies in the PES influence the interaction of an atom with a nonlinear polyatomic molecule. The effects of these anisotropies can be clearly seen in the state-to-state integral cross sections out of the lowest CD3 rotational levels of each nuclear spin symmetry at a collision energy of 440 cm−1. Similarities and differences in the differential cross sections for the ND3–He and CD3–He systems can be linked to the coupling terms derived from the PESs which govern particular initial to final rotational level transitions.
Self-consistent field theory based molecular dynamics with linear system-size scaling
Authors: Richters Dorothee , Kühne Thomas D.
Published: April 2014

We present an improved field-theoretic approach to the grand-canonical potential suitable for linear scaling molecular dynamics simulations using forces from self-consistent electronic structure calculations. It is based on an exact decomposition of the grand canonical potential for independent fermions and does neither rely on the ability to localize the orbitals nor that the Hamilton operator is well-conditioned. Hence, this scheme enables highly accurate all-electron linear scaling calculations even for metallic systems. The inherent energy drift of Born-Oppenheimer molecular dynamics simulations, arising from an incomplete convergence of the self-consistent field cycle, is circumvented by means of a properly modified Langevin equation. The predictive power of the present approach is illustrated using the example of liquid methane under extreme conditions.
Empty liquid phase of colloidal ellipsoids: The role of shape and interaction anisotropy
Authors: Varga Szabolcs , Meneses-Júarez Efrain , Odriozola Gerardo
Published: April 2014

We study the effect of anisotropic excluded volume and attractive interactions on the vapor-liquid phase transition of colloidal ellipsoids. In our model, the hard ellipsoid is embedded into an ellipsoidal well, where both the shape of the hard ellipsoid and that of the added enclosing ellipsoidal well can be varied independently. The bulk properties of these particles are examined by means of a van der Waals type perturbation theory and validated with replica exchange Monte Carlo simulations. It is shown that both the critical volume fraction (ηc) and the critical temperature (Tc) of the vapor-liquid phase transition vanish with increasing shape anisotropy for oblate shapes, while ηc → 0 and Tc ≠ 0 are obtained for very elongated prolate shapes. These results suggest that the chance to stabilize empty liquids (a liquid phase with vanishing density) is higher in suspensions of rod-like colloidal ellipsoids than in those of plate-like ones.
Density functional theory for the description of spherical non-associating monomers in confined media using the SAFT-VR equation of state and weighted density approximations
Authors: Malheiro Carine , Mendiboure Bruno , Plantier Frédéric , Blas Felipe J. , Miqueu Christelle
Published: April 2014

As a first step of an ongoing study of thermodynamic properties and adsorption of complex fluids in confined media, we present a new theoretical description for spherical monomers using the Statistical Associating Fluid Theory for potential of Variable Range (SAFT-VR) and a Non-Local Density Functional Theory (NLDFT) with Weighted Density Approximations (WDA). The well-known Modified Fundamental Measure Theory is used to describe the inhomogeneous hard-sphere contribution as a reference for the monomer and two WDA approaches are developed for the dispersive terms from the high-temperature Barker and Henderson perturbation expansion. The first approach extends the dispersive contributions using the scalar and vector weighted densities introduced in the Fundamental Measure Theory (FMT) and the second one uses a coarse-grained (CG) approach with a unique weighted density. To test the accuracy of this new NLDFT/SAFT-VR coupling, the two versions of the theoretical model are compared with Grand Canonical Monte Carlo (GCMC) molecular simulations using the same molecular model. Only the version with the “CG” approach for the dispersive terms provides results in excellent agreement with GCMC calculations in a wide range of conditions while the “FMT” extension version gives a good representation solely at low pressures. Hence, the “CG” version of the theoretical model is used to reproduce methane adsorption isotherms in a Carbon Molecular Sieve and compared with experimental data after a characterization of the material. The whole results show an excellent agreement between modeling and experiments. Thus, through a complete and consistent comparison both with molecular simulations and with experimental data, the NLDFT/SAFT-VR theory has been validated for the description of monomers.
Embedding potentials for excited states of embedded species
Authors: Wesolowski Tomasz A.
Published: April 2014

Frozen-Density-Embedding Theory (FDET) is a formalism to obtain the upper bound of the ground-state energy of the total system and the corresponding embedded wavefunction by means of Euler-Lagrange equations [T. A. Wesolowski, Phys. Rev. A 77(1), 012504 (2008)]. FDET provides the expression for the embedding potential as a functional of the electron density of the embedded species, electron density of the environment, and the field generated by other charges in the environment. Under certain conditions, FDET leads to the exact ground-state energy and density of the whole system. Following Perdew-Levy theorem on stationary states of the ground-state energy functional, the other-than-ground-state stationary states of the FDET energy functional correspond to excited states. In the present work, we analyze such use of other-than-ground-state embedded wavefunctions obtained in practical calculations, i.e., when the FDET embedding potential is approximated. Three computational approaches based on FDET, that assure self-consistent excitation energy and embedded wavefunction dealing with the issue of orthogonality of embedded wavefunctions for different states in a different manner, are proposed and discussed.
On the stability of two-layer geostrophic point-vortex multipoles
Authors: Kizner Ziv
Published: April 2014

A point-vortex multipole is an ensemble of m+1 vortices (m = 2, 3, …) possessing a m-fold symmetry, with the “core vortex” being located at the centre and m identical “satellite vortices” located at the vertices of an equilateral m-sided polygon (at m > 2) or at the ends of a straight-line segment (at m = 2). At m = 2, m = 3, and m = 4, the multipole is commonly termed a tripole, a quadrupole, and a pentapole, respectively, and the distance from the core vortex to the satellite vortices, the multipole leg. A multipole is said to be stable if, in response to sufficiently small initial perturbations in the distances between the vortices, the variations in the distances remain small for all times. The main issue of this article is an analytical study of the nonlinear stability of point-vortex tripoles characterized by that their core and satellite vortices reside in different layers of a two-layer f-plane quasigeostrophic model. Also the stability of pentapoles and quadrupoles is discussed. The parameters affecting the stability properties of a multipole are the length of its leg and the intensity of the core vortex relative to the satellite vortices. Among the invariants of the dynamical system that describes the motion of an ensemble of m+1 vortices, there are two ones depending on the distances between the vortices only. To establish the stability/instability of a multipole, we consider the restriction of one of the two invariants to the sheet (in the phase space) constituted by the states at which the second invariant takes the same value as at the multipole equilibrium state. Two versions of the method are presented and employed to analyze the stability of collinear states (m = 2) and non-collinear states (m > 2). For tripoles, complete stability analysis is performed resulting in the determination of the regions of stability/instability in the parameter plane. Depending on the parameters, a multipole can rotate clockwise or counterclockwise, and also can be static. A stable static tripole is shown to minimize the energy of interaction between the vortices. Rigorous stability analysis of pentapoles and quadrupoles is carried out under certain constrains on the permissible perturbations: in pentapoles the perturbations should preserve the central symmetry, and in quadrupoles, the zero linear momentum; only quadrupoles with zero total intensity are considered.
A very low noise, high accuracy, programmable voltage source for low frequency noise measurements
Authors: Scandurra Graziella , Giusi Gino , Ciofi Carmine
Published: April 2014

In this paper an approach for designing a programmable, very low noise, high accuracy voltage source for biasing devices under test in low frequency noise measurements is proposed. The core of the system is a supercapacitor based two pole low pass filter used for filtering out the noise produced by a standard DA converter down to 100 mHz with an attenuation in excess of 40 dB. The high leakage current of the supercapacitors, however, introduces large DC errors that need to be compensated in order to obtain high accuracy as well as very low output noise. To this end, a proper circuit topology has been developed that allows to considerably reduce the effect of the supercapacitor leakage current on the DC response of the system while maintaining a very low level of output noise. With a proper design an output noise as low as the equivalent input voltage noise of the OP27 operational amplifier, used as the output buffer of the system, can be obtained with DC accuracies better that 0.05% up to the maximum output of 8 V. The expected performances of the proposed voltage source have been confirmed both by means of SPICE simulations and by means of measurements on actual prototypes. Turn on and stabilization times for the system are of the order of a few hundred seconds. These times are fully compatible with noise measurements down to 100 mHz, since measurement times of the order of several tens of minutes are required in any case in order to reduce the statistical error in the measured spectra down to an acceptable level.
Freestanding sample holder for ultrafast optical spectroscopy at low temperatures
Authors: Yoo S. , Alster J. , Zigmantas D.
Published: April 2014

Ultrafast optical spectroscopy techniques are often employed to gain information about samples that are liquid at room temperature and frozen at cryogenic temperatures. However, the measurements suffer from the presence of unwanted, non-resonant signals originating in the sample cell walls. Most of these artifacts can be avoided in the measurements performed at room temperature by using liquid jet systems, i.e., by removing the sample cell. However, these systems cannot be used in low temperature measurements, when the sample is frozen. Herein we describe a freestanding sample holder that allows low temperature ultrafast spectroscopy measurements free of artifacts caused by the sample cell.
Influence of different illumination profiles on the on-state resistances of silicon carbide photoconductive semiconductor switches
Authors: Wang Langning , Xun Tao , Yang Hanwu , Liu Jinliang , Zhang Yu
Published: April 2014

Characteristics of a silicon-carbide (SiC) photoconductive switch under different illumination profiles are presented. We triggered a V-doped semi-insulated 6H-SiC switch with lateral geometry using a laser beam of 532-nm wavelength. Photoconductivity tests for different spot profiles and locations show that such switches achieve a minimum on-state resistance when the switching gap is illuminated. The differences between on-state resistances are small for various partial illuminations of the switching gap. Semiconductor modeling is used to simulate the electric field and current profiles for different partial illuminations. The simulation results show poor on-state switch performance when partially illuminated. Based on these results, a more revealing circuit model for the switch matches well with experimental results for partial illuminations.
High-pressure Raman scattering in InGaN heteroepitaxial layers: Effect of the substrate on the phonon pressure coefficients
Authors: Oliva R. , Ibáñez J. , Cuscó R. , Dadgar A. , Krost A. , Gandhi J. , Bensaoula A. , Artús L.
Published: April 2014

We perform high-pressure Raman-scattering measurements on different InxGa1-xN/Si(111) epilayers (0.19 < x < 0.45). We find that the experimental pressure coefficient of the A1(LO) mode measured in these samples is larger than that expected from the linear interpolation between the corresponding values of GaN and InN. Similar measurements in InGaN epilayers grown on GaN/sapphire templates yield much lower values, below the linearly interpolated pressure coefficients. We conclude that the phonon pressure coefficients measured in InGaN are mainly determined by the different compressibility of the substrate and epilayer material. Neglecting substrate effects may yield highly inaccurate phonon pressure coefficients and mode Grüneisen parameters.
Nanowell-patterned TiO2 microcantilevers for calorimetric chemical sensing
Authors: Lee Dongkyu , Kim Seonghwan , Chae Inseok , Jeon Sangmin , Thundat Thomas
Published: April 2014

A sensitive calorimetric sensor using a TiO2 microcantilever with nanowells patterned on one of its sides is described. This single material cantilever is sensitive to temperature change without relying on the metal deposition-based bimetallic effect. The thermomechanical sensitivity originates from the structure dependent variations in both the elastic modulus and thermal expansion coefficient due to the presence of ordered nanowells. These cantilever beams offer an alternate and efficient chemical sensing route for vapor phase analytes using photothermal spectroscopy. Selective and sensitive detection of organophosphorus compounds, as well as their photocatalytic decomposition under ultraviolet light exposure are demonstrated.