bluuebunny/crossref_metadata_2025 huggingface dataset:
The metabolic syndrome and risk of coronary artery disease in patients with chronic schizophrenia or schizoaffective disorder in a chronic mental institute
Authors: Tseng Ping‐Tao , Wang Hung‐Yu , Cheng Yu‐Shian , Shen Feng‐Chih , Lin Pao‐Yen , Wu Ching‐Kuan
Published: October 2014

The prevalence rate of metabolic syndrome (MS) and coronary artery disease (CAD) has been found to be high in patients with chronic schizophrenia. Current evidence shows that CAD is underdiagnosed in this group. Our study evaluated the prevalence of MS and the risk of CAD in patients with chronic schizophrenia in a chronic care mental hospital in southern Taiwan. We included all patients with the diagnosis of schizophrenia or schizoaffective disorder. We collected all laboratory, physical examination, psychiatric interview, and chart review data. We also evaluated the risk of CAD in these patients using the Framingham point system. There was no significant age difference in the MS prevalence rate in these patients. The young patients with schizophrenia in our study tended to have a higher prevalence of MS than the general population. In addition, female patients had a higher prevalence rate of MS than males. Based on the Framingham point system, we found the 10‐year risk of CAD to be higher among the patients with schizophrenia than in the general population. Our study highlights the importance of the high risk of MS in both younger and older patients with schizophrenia, without a significant relationship to the use of antipsychotics. More complete cohort studies are needed to confirm these findings. Psychiatrists may want to establish more specific and detailed clinical guidelines for patients with chronic schizophrenia with comorbid physical diseases, especially MS and CAD.
Standards of prescription writing in a long-term psychogeriatric unit: a series of clinical audits
Authors: Wilson L. S. , Devitt P. , Hally O.
Published: October 2014

Objective

The aim of this study was to improve the quality of prescription writing in a long-term psychogeriatric inpatient unit by a combination of serial audits and interventions designed to address the identified deficiencies.

Methods

We undertook three clinical audits of the prescription sheets used in an inpatient unit providing continuing care for residents with severe and enduring mental illness and dementia. Based on the findings of the first audit a set of prescribing guidelines was implemented into the ward. Following the second audit a new prescription sheet was developed. The format of the new prescription sheet was designed to account for the needs of the unit and to adhere to Irish and UK best practise guidelines. Two months after its introduction we undertook a third audit.

Results

Completion of the drug sensitivity box increased from 25% at audit one to 100% at audit three. Other specific aspects of prescription writing that had been poor at the beginning of the audit cycle also showed improvement: prescribing of generic psychotropic drugs increased by 69% and inclusion of the prescribers Medical Council Registration Number increased by 78%. However, some basic aspects of prescription writing remained weak such as frequency of drug administration and documentation of the stop/review date for ‘as required’ medication.

Conclusion

The results of this study suggest that clinical audit and feedback can improve the quality of prescriptions in an in-patient setting.
Dietary gamma-linolenic acid supports arachidonic acid accretion and associated Δ-5 desaturase activity in feline uterine but not ovarian tissues
Authors: Chamberlin Amy J. , Bauer John E.
Published: October 2014

Arachidonic acid (ARA) is essential in felines because conversion of dietary linoleic acid (LA) to ARA is rate-limited by low Δ6-desaturase. Dietary γ-linolenic acid (GLA) may serve as an ARA precursor by-passing this initial rate-limiting step. This possibility was investigated using twenty-six adult female domestic shorthair cats divided into three groups and fed on complete and balanced diets containing high GLA (GL), high LA (HL) or low LA (LL, control) diets, for 300 d prior to ovariohysterectomy. Plasma was obtained 1–2 d before surgery and uterine, ovarian and associated adipose tissues were reserved for lipid analysis. Fatty acid profiles of the plasma phospholipid (PL) fractions and adipose lipids were performed. In the GL group, plasma and uterine tissue PL were significantly enriched in GLA, di-homo GLA (DGLA) and ARA compared with control. However, ovarian and adipose tissue PL were only enriched in DGLA. Enrichment of uterine tissues with DGLA and ARA probably supplies the essential eicosanoid precursors for reproduction when GLA is fed consistently with an active Δ5-desaturase in uterus. By contrast, this enzyme appears less active in ovary because ARA was not higher compared with control. Earlier reports concluded that ARA was not necessary for fertilisation (an ovarian function), but required for successful pregnancy and reproduction (a uterine function). Adipose tissue DGLA may be a reservoir for ARA synthesis by other tissues upon mobilisation. Dietary GLA may meet feline ARA requirements in the absence of an animal-based preformed source of ARA.
A study on allergen sensitivity in patients with allergic rhinitis in Bangalore, India
Authors: Gowda G , Lakshmi S , Parasuramalu B G , Nagaraj C , Gowda B V C , Somashekara K G
Published: October 2014

Background:

Allergic rhinitis is the most common form of non-infectious rhinitis, affecting 500 million people worldwide, with one-fifth of those affected living in the Indian subcontinent. The skin prick test is the most valuable test for detecting offending allergens, and can be helpful for patient education, allergen avoidance and immunotherapy planning.

Method:

The skin prick test was performed with 49 allergens in 486 patients who presented with symptoms of allergic rhinitis, and the allergen profile was studied.

Results:

Of the 486 allergic rhinitis patients, 335 (68.93 per cent) showed allergen positivity to the skin prick test. Dust mite was the most common allergen, with positive results in 44.65 per cent of cases.

Conclusion:

The most common offending allergen in our study was the dust mite. Identification of specific allergens for a particular geographical area aids patient education and enables allergen-specific immunotherapy.
Placing ethnicity at the centre of studies of later life: theoretical perspectives and empirical challenges
Authors: PHILLIPSON CHRIS
Published: October 2014

Research on minority ethnic ageing remains a neglected area within mainstream race and ethnicity studies as well as that of social gerontology. This paper examines the background and reasons for this, arguing that a focus on minority ethnic issues provides a reminder of the complexity of the lifecourse, and of the diversity of ageing as a cultural, economic and social construction. The discussion reviews definitions of ethnicity and their relevance to work in social gerontology. The paper provides an account of early studies of minority ethnic ageing, identifying the strengths and limitations of this research. Later work is then considered, notably that focusing on issues connected with the rise of transnational communities and the changing character of neighbourhoods in urban environments. The paper argues that developing research on minority ethnic ageing has become especially important for understanding the impact of globalisation on re-defining communities, relationships and identities, within and beyond nation states. Globalisation, it is suggested, can be seen as a product of the movement of ethnic groups; equally, ethnic groups are themselves transformed by the possibilities created by global change. The paper concludes with a number of suggestions for embedding work on ethnicity within research in social gerontology.
Digging deep: how organisational culture affects care home residents' experiences
Authors: KILLETT ANNE , BURNS DIANE , KELLY FIONA , BROOKER DAWN , BOWES ALISON , LA FONTAINE JENNY , LATHAM ISABELLE , WILSON MICHAEL , O'NEILL MARTIN
Published: October 2014

Organisational culture of institutions providing care for older people is increasingly recognised as influential in the quality of care provided. There is little research, however, that specifically examines the processes of care home culture and how these may be associated with quality of care. In this paper we draw from an empirical study carried out in the United Kingdom (UK) investigating the relationship between care home culture and residents' experience of care. Eleven UK care homes were included in an in-depth comparative case study design using extensive observation and interviews. Our analysis indicates how organisational cultures of care homes impact on the quality of care residents receive. Seven inter-related cultural elements were of key importance to quality of care. Applying Schein's conceptualisation of organisational culture, we examine the dynamic relationship between these elements to show how organisational culture is locally produced and shifting. A particular organisational culture in a care home cannot be achieved simply by importing a set of organisational values or the ‘right’ leader or staff. Rather, it is necessary to find ways of resolving the everyday demands of practice in ways that are consistent with espoused values. It is through this everyday practice that assumptions continuously evolve, either consistent with or divergent from, espoused values. Implications for policy makers, providers and practitioners are discussed.
Stabilization of overweight prevalence and improvement of dietary habits in French children between 2004 and 2008
Authors: Carriere Caroline , Langevin Coralie , Déti Eduoard Kossi , Barberger-Gateau Pascale , Maurice Sylvie , Thibault Hélène
Published: October 2014

Objective

The objective of the present study was to describe changes in overweight and obesity prevalence and eating habits among 7·5–10·5-year-old children in Aquitaine (France) between 2004 and 2008, and to assess how the programme ‘Nutrition, Prevention and Health of children and teenagers in Aquitaine’ implemented in 2004 may have impacted these changes.

Design

Two cross-sectional studies were conducted in two samples of children: the ‘before programme’ sample during the school year 2004/2005 and the ‘after programme’ sample during the school year 2008/2009.

Settings

Data were collected on gender, age, weight, height, area of residence (rural/urban) and socio-economic status of the school (non-low socio-economic/low socio-economic). Multivariate analyses were used to assess the effect of the regional programme intervention on the evolution of overweight and obesity prevalence and eating habits independently.

Subjects

The ‘before programme’ sample included 1836 children from 163 schools during the school year 2004/2005 and the ‘after programme’ sample included 3483 children from 210 schools during the school year 2008/2009.

Results

After adjustment of the model for age, residential area and socio-economic status of the area of residence, the prevalence of overweight including obesity (OR=1·05; 95 % CI 0·89, 1·23, P=0·56) and of obesity (OR=0·99; 95 % CI 0·71, 1·39, P=0·96) was found to have stabilized and eating habits had improved: intake of light afternoon meals had increased (OR=1·38; 95 % CI 1·13, 1·69, P=0·002) while snacking in the morning (OR=0·50; 95 % CI 0·45, 0·57, P<0·001) and nibbling (OR=0·81; 95 % CI 0·70, 0·93, P<0·001) had decreased.

Conclusions

These results encourage the promotion and implementation of regional and national interventions among children regarding their eating habits in order to stabilize or decrease the prevalence of overweight.
Nutrient-Adjusted High-Fat Diet is Associated with Absence of Periepididymal Adipose Tissue Inflammation: Is there a Link with Adequate Micronutrient Levels?
Authors: Yamada Monica , Maintinguer Norde Marina , Borges Maria C. , Mieko de Meneses Fujii Tatiane , Silva Jacob Patrícia , Fonseca-Alaniz Miriam H. , Cardoso Alonso-Vale Maria I. , Torres-Leal Francisco L. , Tirapegui Julio , Fock Ricardo A. , Borelli Primavera , Curi Rui , Macedo Rogero Marcelo
Published: October 2014

The aim of this study was to investigate the real impact of dietary lipids on metabolic and inflammatory response in rat white adipose tissue. Male healthy Wistar rats were fed ad libitum with a control diet (CON, n=12) or with an adjusted high-fat diet (HFD, n=12) for 12 weeks. Oral glucose and insulin tolerance tests were performed during the last week of the protocol. Plasma fatty acid, lipid profile, body adiposity, and carcass chemical composition were analyzed. Plasma concentration of leptin, adiponectin, C-reactive protein (CRP), TNF-α, IL-6, and monocyte chemotactic protein (MCP-1) was measured. Periepididymal adipose tissue was employed to evaluate TNF-α, MCP-1, and adiponectin gene expression as well as NF-κB pathway and AKT proteins. Isocaloric intake of the adjusted HFD did not induce hyperphagia, but promoted an increase in periepididymal (HFD = 2.94 ± 0.77 vs. CON = 1.99 ± 0.26 g/100 g body weight, p = 0.01) and retroperitoneal adiposity (HFD = 3.11 ± 0.81 vs. CON = 2.08 ± 0.39 g/100 g body weight, p = 0.01) and total body lipid content (HFD = 105.3 ± 20.8 vs. CON = 80.5 ± 7.6 g carcass, p = 0.03). Compared with control rats, HFD rats developed glucose intolerance (p=0.01), dyslipidemia (p = 0.02) and exhibited higher C-reactive protein levels in response to the HFD (HFD = 1002 ± 168 vs. CON = 611 ± 260 ng/mL, p = 0.01). The adjusted HFD did not affect adipokine gene expression or proteins involved in inflammatory signaling, but decreased AKT phosphorylation after insulin stimulation in periepididymal adipose tissue (p = 0.01). In this study, nutrient-adjusted HFD did not induce periepididymal adipose tissue inflammation in rats, suggesting that the composition of HFD differently modulates inflammation in rats, and adequate micronutrient levels may also influence inflammatory pathways.
Erfolgreiches Problemlösen in technologiebasierten Umgebungen: Wechselwirkungen zwischen Interaktionsschritten und Aufgabenanforderungen
Authors: Naumann Johannes , Goldhammer Frank , Rölke Heiko , Stelter Annette
Published: October 2014

Wir zeigen anhand von Feldtestdaten des «Programme for the International Assessment of Adult Competencies» (PIAAC) in Deutschland (N = 661) und Kanada (N = 411), dass sich der Erfolg beim Lösen Technologiebasierter Probleme aus der Anzahl der Interaktionen mit dem System vorhersagen lässt. Dabei war der Zusammenhang umgekehrt U-förmig. Optimale Lösungsraten resultierten bei einer überdurchschnittlichen Anzahl von Interaktionen. Weiterhin wurde der Zusammenhang durch Merkmale der Aufgabe moderiert. Es resultierte vor allem bei Aufgaben, die eine hohe Zahl von Navigationsschritten erfordern, ein stark positiver Zusammenhang. Entgegen den Erwartungen resultierte bei wohl definierten Aufgaben ein höherer Zusammenhang zwischen der Anzahl von Interaktionen und der Lösungsrate als bei schwach definierten Aufgaben. Die Ergebnisse aus der deutschen und kanadischen Stichprobe waren parallel.
Practical Implementation, Characterization and Applications of a Multi-Colour Time-Gated Luminescence Microscope
Authors: Zhang Lixin , Zheng Xianlin , Deng Wei , Lu Yiqing , Lechevallier Severine , Ye Zhiqiang , Goldys Ewa M. , Dawes Judith M. , Piper James A. , Yuan Jingli , Verelst Marc , Jin Dayong
Published: October 2014

Time-gated luminescence microscopy using long-lifetime molecular probes can effectively eliminate autofluorescence to enable high contrast imaging. Here we investigate a new strategy of time-gated imaging for simultaneous visualisation of multiple species of microorganisms stained with long-lived complexes under low-background conditions. This is realized by imaging two pathogenic organisms (Giardia lamblia stained with a red europium probe and Cryptosporidium parvum with a green terbium probe) at UV wavelengths (320–400 nm) through synchronization of a flash lamp with high repetition rate (1 kHz) to a robust time-gating detection unit. This approach provides four times enhancement in signal-to-background ratio over non-time-gated imaging, while the average signal intensity also increases six-fold compared with that under UV LED excitation. The high sensitivity is further confirmed by imaging the single europium-doped Y2O2S nanocrystals (150 nm). We report technical details regarding the time-gating detection unit and demonstrate its compatibility with commercial epi-fluorescence microscopes, providing a valuable and convenient addition to standard laboratory equipment.
Adiabatic Quantum Simulation of Quantum Chemistry
Authors: Babbush Ryan , Love Peter J. , Aspuru-Guzik Alán
Published: October 2014

We show how to apply the quantum adiabatic algorithm directly to the quantum computation of molecular properties. We describe a procedure to map electronic structure Hamiltonians to 2-body qubit Hamiltonians with a small set of physically realizable couplings. By combining the Bravyi-Kitaev construction to map fermions to qubits with perturbative gadgets to reduce the Hamiltonian to 2-body, we obtain precision requirements on the coupling strengths and a number of ancilla qubits that scale polynomially in the problem size. Hence our mapping is efficient. The required set of controllable interactions includes only two types of interaction beyond the Ising interactions required to apply the quantum adiabatic algorithm to combinatorial optimization problems. Our mapping may also be of interest to chemists directly as it defines a dictionary from electronic structure to spin Hamiltonians with physical interactions.
Rapid fabrication of self-assembled interfacial film decorated filter paper as an excellent surface-enhanced Raman scattering substrate
Authors: Hasi Wu-Li-Ji , Lin Shuang , Lin Xiang , Lou Xiu-Tao , Yang Fang , Lin Dian-Yang , Lu Zhi-Wei
Published: October 2014

The fabrication of this paper-based SERS substrate is facile and rapid (<10 min). The coverage rate of Ag NPs is relatively high.
Protein–polymer therapeutics: a macromolecular perspective
Authors: Wu Yuzhou , Ng David Y. W. , Kuan Seah Ling , Weil Tanja
Published: October 2014

The development of protein–polymer hybrids emerged several decades ago with the vision that their synergistic combination will offer macromolecular hybrids with manifold features to succeed as the next generation therapeutics.
An evaluation of the “GGP” personal samplers under semi-volatile aerosols: sampling losses and their implication on occupational risk assessment
Authors: Dragan George C. , Breuer Dietmar , Blaskowitz Morten , Karg Erwin , Schnelle-Kreis Jürgen , Arteaga-Salas Jose M. , Nordsieck Hermann , Zimmermann Ralf
Published: October 2014

Left: GGP personal sampler. Right: partcile–vapour fractionation of a semi-volatile aerosol.
Environmental release, fate and ecotoxicological effects of manufactured ceria nanomaterials
Authors: Collin Blanche , Auffan Mélanie , Johnson Andrew C. , Kaur Inder , Keller Arturo A. , Lazareva Anastasiya , Lead Jamie R. , Ma Xingmao , Merrifield Ruth C. , Svendsen Claus , White Jason C. , Unrine Jason M.
Published: October 2014

This critical review presents the sources and sinks of nanoceria in the environment, detection and characterization methods, fate and transport processes, toxicity and likelihood of toxicity in soil and water.
Correlating the structure and in vitro digestion viscosities of different pectin fibers to in vivo human satiety
Authors: Logan Kirstyn , Wright Amanda J. , Goff H. Douglas
Published: October 2014

Low methoxyl pectin induced more satiety compared to other pectins, but the results were not strongly correlated to digestate viscosity.
Effect of substrate discontinuities on the propagating surface plasmon polariton modes in gold nanobars
Authors: Johns Paul , Yu Kuai , Devadas Mary Sajini , Li Zhongming , Major Todd A. , Hartland Gregory V.
Published: October 2014

The surface plasmon polariton modes of gold nanobars have been investigated by scanning pump–probe microscopy experiments and finite element calculations.
Three-dimensional scanning near field optical microscopy (3D-SNOM) imaging of random arrays of copper nanoparticles: implications for plasmonic solar cell enhancement
Authors: Ezugwu Sabastine , Ye Hanyang , Fanchini Giovanni
Published: October 2014

A 3D-SNOM imaging technique is used to design plasmonically enhanced organic solar cells with a threefold increase in photoconversion efficiency by the application of a 200 nm SiO2 spacer between an array of Cu nanoparticles and the active layer.
Amphiphilic copolymer coated upconversion nanoparticles for near-infrared light-triggered dual anticancer treatment
Authors: Yang Shun , Li Najun , Liu Zhuang , Sha Wenwei , Chen Dongyun , Xu Qingfeng , Lu Jianmei
Published: October 2014

The light-triggered controlled release of anticancer drugs accompanied with NIR-responsive photodynamic therapy was performed via a self-assembly process. Under 980 nm laser, the cancer cells could be effectively inhibited by released drugs and singlet oxygen simultaneously.
Novel biocompatible fluorescent polymeric micelles based on 1,8-naphthalimide derivatives for cell imaging
Authors: Liu Bei-Yu , Wu Wan-Xia , Wang Na , Yu Xiao-Qi
Published: October 2014

A new type of fluorescent polymeric micelle was developed by the aqueous self-assembly from amphiphilic block copolymers via click chemistry and showed good potential for application in cell imaging with good biocompatibility. Notably, P1 can readily serve as an excellent intracellular pH sensor in whole living cells based on PET inhibition
Self-stabilized Pt–Rh bimetallic nanoclusters as durable electrocatalysts for dioxygen reduction in PEM fuel cells
Authors: Narayanamoorthy B. , Datta K. K. R. , Eswaramoorthy M. , Balaji S.
Published: October 2014

Self-stabilized Pt–Rh nanoclusters (NCs) were prepared by formic acid reduction and used as the durable electrocatalyst for ORR.
An organometallic structure-activity relationship study reveals the essential role of a Re(CO)3moiety in the activity against gram-positive pathogens including MRSA
Authors: Patra Malay , Wenzel Michaela , Prochnow Pascal , Pierroz Vanessa , Gasser Gilles , Bandow Julia E. , Metzler-Nolte Nils
Published: October 2014

A systematic structure activity relationship reveals the contribution of individual organometallic moieties to the potency of a new structural class of hetero-trimetallic antibacterial agents.
Chiral random grain boundary phase of achiral hockey-stick liquid crystals
Authors: Chen Dong , Wang Haitao , Li Min , Glaser Matthew A. , Maclennan Joseph E. , Clark Noel A.
Published: October 2014

Chiral random grain boundary phase of achiral hockey-stick liquid crystals showing randomly oriented smectic blocks with flat smectic layers.
Combustion synthesis of porous Pt-functionalized SnO2 sheets for isopropanol gas detection with a significant enhancement in response
Authors: Dong Chengjun , Liu Xu , Xiao Xuechun , Chen Gang , Wang Yude , Djerdj Igor
Published: October 2014

A Pt-functionalized SnO2 sheet based gas sensor displayed a response value of 190.5 for 100 ppm isopropanol gas.
Nanoconfinement of phase change materials within carbon aerogels: phase transition behaviours and photo-to-thermal energy storage
Authors: Huang Xinyu , Xia Wei , Zou Ruqiang
Published: October 2014

Nanoconfinement of octadecanol within carbon aerogels leads to a novel phase change composite with various phase transition behaviours for photo-to-thermal energy transformation and storage.
Significance of wall number on the carbon nanotube support-promoted electrocatalytic activity of Pt NPs towards methanol/formic acid oxidation reactions in direct alcohol fuel cells
Authors: Yuan Weiyong , Cheng Yi , Shen Pei Kang , Li Chang Ming , Jiang San Ping
Published: October 2014

The inner walls of CNTs have a significant effect on the electrocatalytic activity of supported Pt NPs for MOR/FAOR in fuel cells.
Two-step reduction of self-assembed three-dimensional (3D) reduced graphene oxide (RGO)/zinc oxide (ZnO) nanocomposites for electromagnetic absorption
Authors: Wu Fan , Xia Yilu , Wang Yuan , Wang Mingyang
Published: October 2014

Graphene oxide and zinc oxide nanoparticles have formed a three-dimensional nanocomposite with a high performance of electromagnetic absorption via a hydrothermal process. UV-irradiation removed the remaining oxygen functional groups from the skeleton of the reduced graphene oxide.
High‐frequency modelling of a three‐phase pulse width modulation inverter towards the dc bus considering line and controller harmonics
Authors: Haghbin Saeid , Rabiei Ali , Thiringer Torbjörn
Published: October 2014

Closed‐form analytical formulas are provided to calculate the dc bus harmonics of a three‐phase sinusoidal pulse width modulation (SPWM) inverter. The harmonic analysis is performed by using a double Fourier series approach to determine the dc bus current frequency spectrum. For an arbitrary modulation index and load power factor, the full harmonic components of the inverter dc side current are calculated. Based on the developed analytical model, an equivalent circuit is proposed for the inverter harmonic analysis towards the dc bus. Moreover, the impacts of line harmonics and zero sequence injection in controller towards the dc bus are presented. The results show that the 5th and 7th ac line harmonics on the dc side current is appearance of the 6th harmonic in the dc side. The impact of zero sequence injection to the controller on the dc side is negligible. In addition to analytical formulation, different simulations and extensive measurements performed which the results verified the presented analytical framework.
An electrochemical cell for in operando studies of lithium/sodium batteries using a conventional x-ray powder diffractometer
Authors: Shen Yanbin , Pedersen Erik E. , Christensen Mogens , Iversen Bo B.
Published: October 2014

An electrochemical cell has been designed for powder X-ray diffraction studies of lithium ion batteries (LIB) and sodium ion batteries (SIB) in operando with high time resolution using a conventional powder X-ray diffractometer. The cell allows for studies of both anode and cathode electrode materials in reflection mode. The cell design closely mimics that of standard battery testing coin cells and allows obtaining powder X-ray diffraction patterns under representative electrochemical conditions. In addition, the cell uses graphite as the X-ray window instead of beryllium, and it is easy to operate and maintain. Test examples on lithium insertion/extraction in two spinel-type LIB electrode materials (Li4Ti5O12 anode and LiMn2O4 cathode) are presented as well as first results on sodium extraction from a layered SIB cathode material (Na0.84Fe0.56Mn0.44O2).
The extreme nonlinear optics of gases and femtosecond optical filamentation
Authors: Milchberg H. M. , Chen Y.-H. , Cheng Y.-H. , Jhajj N. , Palastro J. P. , Rosenthal E. W. , Varma S. , Wahlstrand J. K. , Zahedpour S.
Published: October 2014

Under certain conditions, powerful ultrashort laser pulses can form greatly extended, propagating filaments of concentrated high intensity in gases, leaving behind a very long trail of plasma. Such filaments can be much longer than the longitudinal scale over which a laser beam typically diverges by diffraction, with possible applications ranging from laser-guided electrical discharges to high power laser propagation in the atmosphere. Understanding in detail the microscopic processes leading to filamentation requires ultrafast measurements of the strong field nonlinear response of gas phase atoms and molecules, including absolute measurements of nonlinear laser-induced polarization and high field ionization. Such measurements enable the assessment of filamentation models and make possible the design of experiments pursuing applications. In this paper, we review filamentation in gases and some applications, and discuss results from diagnostics developed at Maryland for ultrafast measurements of laser-gas interactions.
Laser desorption time-of-flight mass spectrometry of ultraviolet photo-processed ices
Authors: Paardekooper D. M. , Bossa J.-B. , Isokoski K. , Linnartz H.
Published: October 2014

A new ultra-high vacuum experiment is described that allows studying photo-induced chemical processes in interstellar ice analogues. MATRI2CES - a Mass Analytical Tool to study Reactions in Interstellar ICES applies a new concept by combining laser desorption and time-of-flight mass spectrometry with the ultimate goal to characterize in situ and in real time the solid state evolution of organic compounds upon UV photolysis for astronomically relevant ice mixtures and temperatures. The performance of the experimental setup is demonstrated by the kinetic analysis of the different photoproducts of pure methane (CH4) ice at 20 K. A quantitative approach provides formation yields of several new species with up to four carbon atoms. Convincing evidence is found for the formation of even larger species. Typical mass resolutions obtained range from M/ΔM ∼320 to ∼400 for CH4 and argon, respectively. Additional tests show that the typical detection limit (in monolayers) is ⩽0.02 ML, substantially more sensitive than the regular techniques used to investigate chemical processes in interstellar ices.
Thermal desorption spectroscopy from the surfaces of metal-oxide-semiconductor nanostructures
Authors: Meyburg Jan Philipp , Nedrygailov Ievgen I. , Hasselbrink Eckart , Diesing Detlef
Published: October 2014

An experimental setup, which combines direct heating and temperature measurement of metal nanofilms allowing temperature programmed desorption experiments is described. This setup enables the simultaneous monitoring of the thermal desorption flux from the surface of chemi-electric devices and detection of chemically induced hot charge carriers under UHV conditions. This method is demonstrated for the case of water desorption from a Pt/SiO2-n-Si metal-oxide-semiconductor nanostructure.
Interfacial water in the vicinity of a positively charged interface studied by steady-state and time-resolved heterodyne-detected vibrational sum frequency generation
Authors: Singh Prashant Chandra , Nihonyanagi Satoshi , Yamaguchi Shoichi , Tahara Tahei
Published: October 2014

To investigate the properties of water in the close vicinity of a positively charged surfactant/water interface, steady-state and femtosecond time-resolved interfacial vibrational spectra were measured in the presence of excess alkali halide salts. The steady-state Imχ(2) spectra show a drastic intensity decrease with excess salts, indicating that the thickness of the probed water layer is substantially reduced. Fluoride salts do not noticeably affect spectral features in the OH stretch region whereas the chloride and bromide salts induce significant blue shifts of the OH stretch frequency. Femtosecond time-resolved ΔImχ(2) spectra obtained with fluoride salts exhibit a very broad bleach even at 0 fs as observed without excess salts, while chloride and bromide salts give rise to a narrow spectral hole burning. These results indicate that the excess chloride and bromide ions strongly interact with interfacial water in the vicinity of the charged interface and it suppresses intramolecular coupling (i.e., Fermi resonance) that causes spectral broadening.
Design and experiment of generalized triple-cross-spring flexure pivots applied to the ultra-precision instruments
Authors: Liu Lang , Bi Shusheng , Yang Qizi , Wang Yuliang
Published: October 2014

Owing to the excellent performance, the generalized cross-spring flexure pivots (GCSFP), formed by two symmetric crossing leaves at an arbitrary position along the radial direction, had been widely used in precision instruments. However, the accuracy of GCSFPs is lower than the required one for some ultra-precision instruments. Especially for the large angles, the axis drift of GCSFPs cannot be ignored. By adding a spring to a GCSFP, a novel flexure pivot, which called generalized triple-cross-spring flexure pivot (GTCSFP), can be obtained. Finite element analysis shows that GTCSFPs can achieve ultra-high precision. The axis drift is less than 0.3 μm for a ±10° motion range. Several prototypes of GTCSFP were designed and manufactured. Rotational stiffness, radial stiffness, axial stiffness, axis drift, temperature drift, and fatigue life were measured. The result shows that GTCSFPs have many advantages, such as high precision, long service life, large movement range, and high off-axis/axial stiffness ratio. Thus, GTCSFPs have potential applications in the field of precision instruments.
Effects of reagent rotational excitation on the H + CHD3 → H2 + CD3 reaction: A seven dimensional time-dependent wave packet study
Authors: Zhang Zhaojun , Zhang Dong H.
Published: October 2014

Seven-dimensional time-dependent wave packet calculations have been carried out for the title reaction to obtain reaction probabilities and cross sections for CHD3 in J0 = 1, 2 rotationally excited initial states with k0 = 0 − J0 (the projection of CHD3 rotational angular momentum on its C3 axis). Under the centrifugal sudden (CS) approximation, the initial states with the projection of the total angular momentum on the body fixed axis (K0) equal to k0 are found to be much more reactive, indicating strong dependence of reactivity on the orientation of the reagent CHD3 with respect to the relative velocity between the reagents H and CHD3. However, at the coupled-channel (CC) level this dependence becomes much weak although in general the K0 specified cross sections for the K0 = k0 initial states remain primary to the overall cross sections, implying the Coriolis coupling is important to the dynamics of the reaction. The calculated CS and CC integral cross sections obtained after K0 averaging for the J0 = 1, 2 initial states with all different k0 are essentially identical to the corresponding CS and CC results for the J0 = 0 initial state, meaning that the initial rotational excitation of CHD3 up to J0 = 2, regardless of its initial k0, does not have any effect on the total cross sections for the title reaction, and the errors introduced by the CS approximation on integral cross sections for the rotationally excited J0 = 1, 2 initial states are the same as those for the J0 = 0 initial state.
Fast, purely growing collisionless reconnection as an eigenfunction problem related to but not involving linear whistler waves
Authors: Bellan Paul M.
Published: October 2014

If either finite electron inertia or finite resistivity is included in 2D magnetic reconnection, the two-fluid equations become a pair of second-order differential equations coupling the out-of-plane magnetic field and vector potential to each other to form a fourth-order system. The coupling at an X-point is such that out-of-plane even-parity electric and odd-parity magnetic fields feed off each other to produce instability if the scale length on which the equilibrium magnetic field changes is less than the ion skin depth. The instability growth rate is given by an eigenvalue of the fourth-order system determined by boundary and symmetry conditions. The instability is a purely growing mode, not a wave, and has growth rate of the order of the whistler frequency. The spatial profile of both the out-of-plane electric and magnetic eigenfunctions consists of an inner concave region having extent of the order of the electron skin depth, an intermediate convex region having extent of the order of the equilibrium magnetic field scale length, and a concave outer exponentially decaying region. If finite electron inertia and resistivity are not included, the inner concave region does not exist and the coupled pair of equations reduces to a second-order differential equation having non-physical solutions at an X-point.
Measurement of the nuclear polarization of hydrogen and deuterium molecules using a Lamb-shift polarimeter
Authors: Engels Ralf , Gorski Robert , Grigoryev Kiril , Mikirtychyants Maxim , Rathmann Frank , Seyfarth Hellmut , Ströher Hans , Weiss Philipp , Kochenda Leonid , Kravtsov Peter , Trofimov Viktor , Tschernov Nikolay , Vasilyev Alexander , Vznuzdaev Marat , Schieck Hans Paetz gen.
Published: October 2014

Lamb-shift polarimeters are used to measure the nuclear polarization of protons and deuterons at energies of a few keV. In combination with an ionizer, the polarization of hydrogen and deuterium atoms was determined after taking into account the loss of polarization during the ionization process. The present work shows that the nuclear polarization of hydrogen or deuterium molecules can be measured as well, by ionizing the molecules and injecting the \documentclass[12pt]{minimal}\begin{document}$H_2^+$\end{document}H2+ (or \documentclass[12pt]{minimal}\begin{document}$D_2^+$\end{document}D2+) ions into the Lamb-shift polarimeter.
Femtosecond laser direct writing of monocrystalline hexagonal silver prisms
Authors: Vora Kevin , Kang SeungYeon , Moebius Michael , Mazur Eric
Published: October 2014

Bottom-up growth methods and top-down patterning techniques are both used to fabricate metal nanostructures, each with a distinct advantage: One creates crystalline structures and the other offers precise positioning. Here, we present a technique that localizes the growth of metal crystals to the focal volume of a laser beam, combining advantages from both approaches. We report the fabrication of silver nanoprisms—hexagonal nanoscale silver crystals—through irradiation with focused femtosecond laser pulses. The growth of these nanoprisms is due to a nonlinear optical interaction between femtosecond laser pulses and a polyvinylpyrrolidone film doped with silver nitrate. The hexagonal nanoprisms have bases hundreds of nanometers in size and the crystal growth occurs over exposure times of less than 1 ms (8 orders of magnitude faster than traditional chemical techniques). Electron backscatter diffraction analysis shows that the hexagonal nanoprisms are monocrystalline. The fabrication method combines advantages from both wet chemistry and femtosecond laser direct-writing to grow silver crystals in targeted locations. The results presented in this letter offer an approach to directly positioning and growing silver crystals on a substrate, which can be used for plasmonic devices.
Probing thyroglobulin in undiluted human serum based on pattern recognition and competitive adsorption of proteins
Authors: Wang Ran , Huang Shuai , Li Jing , Chae Junseok
Published: October 2014

Thyroglobulin (Tg) is a sensitive indicator of persistent or recurrent differentiated thyroid cancer of follicular cell origin. Detection of Tg in human serum is challenging as bio-receptors, such as anti-Tg, used in immunoassay have relatively weak binding affinity. We engineer sensing surfaces using the competitive adsorption of proteins, termed the Vroman Effect. Coupled with Surface Plasmon Resonance, the “cross-responsive” interactions of Tg on the engineered surfaces produce uniquely distinguishable multiple signature patterns, which are discriminated using Linear Discriminant Analysis. Tg-spiked samples, down to 2 ng/ml Tg in undiluted human serum, are sensitively and selectively discriminated from the control (undiluted human serum).
Multiphonon resonant Raman scattering in non-polar GaN epilayers
Authors: Kumar Mukesh , Becker M. , Wernicke T. , Singh R.
Published: October 2014

Multiphonon resonant Raman scattering in non-polar a-plane (112¯0) GaN epitaxial layers grown on sapphire substrate were investigated. We report longitudinal optical phonon overtones up to seventh order in a-plane GaN epilayer, which has rarely been observed earlier in GaN. However, for high quality polar c-plane (0001) GaN epilayer and semi-polar r-plane (112¯2) GaN epilayer, resonant Raman spectra were not very prominent. Strong multiphonon resonant Raman scattering process is explained by exciton-mediated multiphonon Raman scattering and defect-induced Fröhlich interaction.
Larmor electric field observed at the Earth's magnetopause by Polar satellite
Authors: Koga D. , Gonzalez W. D. , Mozer F. S. , Silveira M. V. D. , Cardoso F. R.
Published: October 2014

We present, for the first time, observational evidence of a kinetic electric field near the X-line associated with asymmetric reconnection at the Earth's dayside magnetopause using Polar observations. On March 29, 2003, Polar satellite detected an asymmetric collisionless reconnection event. This event shows a unipolar Hall electric field signature and a simple deviation from the guide field during the magnetopause crossing, with the absence of an ion plasma jet outflow indicating that the magnetopause crossing was near the X-line. As expected from particle-in-cell simulations by Malakit et al. (Phys. Rev. Lett. 111, 135001 (2013)), an earthward pointing normal electric field appears in the magnetospheric side of the ion diffusion region. The electric field satisfies two necessary conditions for the existence of the finite ion Larmor radius effect: (1) the ion Larmor radius (rg2) is larger than the distance between the stagnation point and the edge of the ion diffusion region in the strong magnetic field side (δS2) and (2) the spatial extent of the kinetic electric field (δEL) is of the order of the ion Larmor radius. Furthermore, it is shown that the peak value of the Larmor electric field is comparable to the predicted value. The observation of the Larmor electric field can be valuable in other analyses to show that the crossing occurred near the X-line.
Effect of multiply charged ions on the performance and beam characteristics in annular and cylindrical type Hall thruster plasmas
Authors: Kim Holak , Lim Youbong , Choe Wonho , Seon Jongho
Published: October 2014

Plasma plume and thruster performance characteristics associated with multiply charged ions in a cylindrical type Hall thruster (CHT) and an annular type Hall thruster are compared under identical conditions such as channel diameter, channel depth, propellant mass flow rate. A high propellant utilization in a CHT is caused by a high ionization rate, which brings about large multiply charged ions. Ion currents and utilizations are much different due to the presence of multiply charged ions. A high multiply charged ion fraction and a high ionization rate in the CHT result in a higher specific impulse, thrust, and discharge current.
Fowler-Nordheim tunneling at SiO2/4H-SiC interfaces in metal-oxide-semiconductor field effect transistors
Authors: Fiorenza Patrick , Frazzetto Alessia , Guarnera Alfio , Saggio Mario , Roccaforte Fabrizio
Published: October 2014

The conduction mechanisms and trapping effects at SiO2/4H-SiC interfaces in metal-oxide-semiconductor field effect transistors (MOSFETs) were studied by Fowler-Nordheim (FN) tunnelling and frequency dependent conductance measurements. In particular, the analysis of both MOS capacitors and MOSFETs fabricated on the same wafer revealed an anomalous FN behavior on p-type implanted SiC/SiO2 interfaces. The observed FN instability upon subsequent voltage sweeps was correlated to the charge-discharge of hole trap states close the valence band edge of 4H-SiC. The charge-discharge of these traps also explained the recoverable threshold voltage instability observed in lateral MOSFETs.
Interfacial tension based on-chip extraction of microparticles confined in microfluidic Stokes flows
Authors: Huang Haishui , He Xiaoming
Published: October 2014

Microfluidics involving two immiscible fluids (oil and water) has been increasingly used to produce hydrogel microparticles with wide applications. However, it is difficult to extract the microparticles out of the microfluidic Stokes flows of oil that have a Reynolds number (the ratio of inertia to viscous force) much less than one, where the dominant viscous force tends to drive the microparticles to move together with the surrounding oil. Here, we present a passive method for extracting hydrogel microparticles in microfluidic Stokes flow from oil into aqueous extracting solution on-chip by utilizing the intrinsic interfacial tension between oil and the microparticles. We further reveal that the thickness of an “extended confining layer” of oil next to the interface between oil and aqueous extracting solution must be smaller than the radius of microparticles for effective extraction. This method uses a simple planar merging microchannel design that can be readily fabricated and further integrated into a fluidic system to extract microparticles for wide applications.
Optical tuning of phosphors by plasmonic gold nanoparticles for phosphor-converted white light emitting diodes
Authors: Kim Myeongcheol , Lee Seong Min , Choi Kyung Cheol
Published: October 2014

We report a localized surface plasmonic enhanced phosphor using Au nanoparticles. The method is simple and widely used for various phosphor materials. When the localized surface plasmon resonance of Au nanoparticles matches the emission wavelength of the phosphor materials, the efficiency of the phosphor is enhanced. The phosphor luminance intensity is enhanced with the application of an optimum concentration of Au nanoparticles. In order to check the wavelength-dependent effect of localized surface plasmon resonance, we experimented with different phosphor materials, having emission wavelength peaks at 520 nm, 560 nm, and 620 nm. We found the differences in plasmonic enhancement by the wavelength dependency.
Replication and characterization of the compound eye of a fruit fly for imaging purpose
Authors: Li Hefu , Gong Xianwei , Ni Qiliang , Zhao Jingli , Zhang Hongsheng , Wang Taisheng , Yu Weixing
Published: October 2014

In this work, we report the replication and characterization of the compound eye of a fruit fly for imaging purpose. In the replication, soft lithography method was employed to replicate the compound eye of a fruit fly into a UV-curable polymer. The method was demonstrated to be effective and the compound eye is replicated into the polymer (NOA78) where each ommatidium has a diameter of about 30 μm and a sag height of about 7 μm. To characterize its optical property, the point spread function of the compound eye was tested and a NA of 0.386 has been obtained for the replicated polymeric ommatidium. Comparing with the NA of a real fruit fly ommatidium which was measured to be about 0.212, the replicated polymeric ommatidium has a much larger NA due to the refractive index of NOA78 is much higher than that of the material used to form the real fruit fly ommatidium. Furthermore, the replicated compound eye was used to image a photomask patterned with grating structures to test its imaging property. It is shown that the grating with a line width of 20 μm can be clearly imaged. The image of the grating formed by the replicated compound eye was shrunk by about 10 times and therefore a line width of about 2.2 μm in the image plane has been obtained, which is close to the diffraction limited resolution calculated through the measured NA. In summary, the replication method demonstrated is effective and the replicated compound eye has the great potential in optical imaging.
GeO2/Ge structure submitted to annealing in deuterium: Incorporation pathways and associated oxide modifications
Authors: Bom N. M. , Soares G. V. , Hartmann S. , Bordin A. , Radtke C.
Published: October 2014

Deuterium (D) incorporation in GeO2/Ge structures following D2 annealing was investigated. Higher D concentrations were obtained for GeO2/Ge samples in comparison to their SiO2/Si counterparts annealed in the same conditions. Oxygen vacancies produced during the annealing step in D2 constitute defect sites for D incorporation, analogous to defects at the SiO2/Si interfacial region. Besides D incorporation, volatilization of the oxide layer is also observed as a consequence of D2 annealing, especially in the high temperature regime of the present study (>450 °C). In parallel to this volatilization, the stoichiometry and chemical structure of remnant oxide are modified as well. These results evidence the broader impact of forming gas annealing in dielectric/Ge structures with respect to SiO2/Si counterparts.