bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Steam‐Redissolution on Transmission Characteristics of 17 × 17 Polymer Arrayed Waveguide Grating Multiplexers
Authors: Qin Zheng‐kun , Yu Yue , Zhang Hui‐Ping , Wang Guo‐Feng , Wang Yu‐Hai , Ma Chun‐Sheng
Published: June 2013

In this article, the RIE process has been improved, a
polymer arrayed waveguide grating (AWG) multiplexer with flat spectral response have been designed and fabricated using FPE polymer materials. Using the steam‐redissolution technique, the insertion loss and the crosstalk have been reduced. Experimental results show that the central wavelength is 1550.86 nm, and 3‐dB bandwidth is about 0.478 nm, insertion loss is 10.5 dB, crosstalk is about −20.5 dB. The insertion loss of an AWG device is reduced by about 3 dB for the central channel and 4.5 dB for the edge channels, and the crosstalk is reduced by 1.5 dB after the steam‐redissolution. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2199–2201, 2013
A Bidirectional Left‐Hand Circularly Polarized Antenna Using Dual Rotated Patches
Authors: Deng Changjiang , Li Yue , Zhang Zhijun , Wang Jianwu , Feng Zhenghe
Published: June 2013

In this article, we have proposed a multilayer bidirectional circularly polarized antenna for underground communications. The proposed antenna consists of two slot‐coupled back‐to‐back arranged rotated patches and a microstrip feed‐line. Identical left‐hand circular polarization is achieved in both front and back directions to avoid the undesired polarization mismatch for point‐to‐point connection. A prototype of the proposed antenna is built to validate the design strategy. The measured data, including S‐parameter, axial ratio, radiation pattern, and gain, agree well with the simulation results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2044–2047, 2013
Ultra‐Wideband Planar Monopole Antennas with Improved Characteristics
Authors: Lages André V. S. , Dmitriev Victor , Kawakatsu Marcelo N. , Nascimento Daniel C. , Ferreira Daniel B. , da Costa Ewerton S.
Published: June 2013

Two planar elliptical ultra‐wideband (UWB) monopole antennas with total efficiency greater than 97% in the UWB are investigated. One has attractive feature and an excellent impedance matching with return loss lower than −22 dB in the whole UWB and the other one has very good radiation pattern characteristics. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2149–2154, 2013
Polar decomposition based corotational framework for triangular shell elements with distributed loads
Authors: Caselli Federica , Bisegna Paolo
Published: June 2013

A polar decomposition based corotational formulation for deriving geometrically nonlinear triangular shell elements is proposed. This formulation is novel in two aspects. (1) Original formulas for the projector operator and its variation are presented, leading to simple algorithms for the computation of the nodal residual vector and of the consistent tangent stiffness tensor. (2) For the first time in the context of a corotational kinematic description, a rigorous treatment of distributed dead and follower loads is performed, thoroughly accounting for the various contributions entailed in the residual vector and in the tangent stiffness. Numerical simulations of popular benchmark problems are reported, showing the effectiveness of the proposed approach. An accessible and adaptable MATLAB toolkit implementing the present formulation is provided as supplementary material. Copyright © 2013 John Wiley & Sons, Ltd.
Clinical characteristics and outcomes of chédiak–Higashi syndrome: A nationwide survey of Japan
Authors: Nagai Kozo , Ochi Fumihiro , Terui Kiminori , Maeda Miho , Ohga Shouichi , Kanegane Hirokazu , Kitoh Toshiyuki , Kogawa Kazuhiro , Suzuki Nobuhiro , Ohta Shigeru , Ishida Yasushi , Okamura Takayuki , Wakiguchi Hiroshi , Yasukawa Masaki , Ishii Eiichi
Published: June 2013

Background

Chédiak–Higashi syndrome (CHS) is a rare autosomal recessive disorder characterized by immunodeficiency, neurological dysfunction, and oculocutaneous albinism. Recently, several clinical CHS phenotypes have been reported. Here, we report results of a nationwide survey performed to clarify clinical characteristics and outcomes of CHS patients in Japan.

Methods

Questionnaires were sent to 287 institutions to collect data regarding CHS patients diagnosed between 2000 and 2010, including results of lysosomal trafficking regulator (LYST) gene analysis. Cytotoxicity and degranulation activity of cytotoxic T lymphocytes were analyzed in available patient samples.

Results

A total of 15 patients diagnosed with CHS were eligible for enrollment in this study. Of these, 10 (67%) had recurrent bacterial infections, five (33%) developed life‐threatening hemophagocytic lymphohistiocytosis (HLH), and one patient had complicated malignant lymphoma. Hematopoietic stem cell transplantation (HSCT) was performed for six patients including three with HLH, and 10 of the enrolled patients have survived at the time of this writing. LYST analysis was performed for 10 patients; seven different mutations were detected in seven patients, whereas no mutation was identified in three patients. Cytotoxicity and degranulation activity were impaired in patients with and without LYST mutation.

Discussion

Results of this survey indicate that one or two patients with CHS were newly diagnosed each year in Japan. The incidence of HLH was not as high as expected. Mutations of genes other than LYST were suspected in some cases. We conclude that determining indication for HSCT for CHS patients should be based on genetic and cytotoxic analysis. Pediatr Blood Cancer 2013;60:1582–1586. © 2013 Wiley Periodicals, Inc.
Does website‐based information add any value in counseling mothers expecting a baby with severe congenital diaphragmatic hernia?
Authors: Engels Alexander C. , DeKoninck Philip , van der Merwe Johannes L. , Van Mieghem Tim , Stevens Petra , Power Beverley , Nicolaides Kypros H. , Gratacos Eduard , Deprest Jan A.
Published: June 2013

Objective

We aimed to measure whether website‐provided information about congenital diaphragmatic hernia (CDH) and fetal therapy for severe cases provides added value compared with clinical counseling of parents.

Methods

This is a single center study in 102 couples who earlier opted for fetoscopic endoluminal tracheal occlusion (FETO) because of isolated severe CDH. They were asked to fill out an anonymized web‐based survey of 12 questions. Then, they were offered access to information on the web pages of the randomized Tracheal Occlusion to Accelerate Lung Growth (TOTAL) trial. One week later, their appreciation was measured again by a second questionnaire.

Results

Eighty‐two (80%) parents completed the first questionnaire, and 48 (47%) completed the entire survey. Several items became more clear to the parents after reading the website, such as the length of hospital stay (23.2% prior to web information, 60.4% after; P = 0.004), maternal risk, or the requirement of fetal anesthesia for FETO (43.9% resp. 79.2%; P = <0.001).

Conclusion

Complementing prenatal counseling on CDH and FETO by standardized information via website is perceived by parents as of added value. Maternal risks and the need for fetal medication need more clarification during the verbal counseling prior to prenatal interventions. © 2013 John Wiley & Sons, Ltd.
Urea‐temperature phase diagrams capture the thermodynamics of denatured state expansion that accompany protein unfolding
Authors: Tischer Alexander , Auton Matthew
Published: June 2013

We have analyzed the thermodynamic properties of the von Willebrand factor (VWF) A3 domain using urea‐induced unfolding at variable temperature and thermal unfolding at variable urea concentrations to generate a phase diagram that quantitatively describes the equilibrium between native and denatured states. From this analysis, we were able to determine consistent thermodynamic parameters with various spectroscopic and calorimetric methods that define the urea–temperature parameter plane from cold denaturation to heat denaturation. Urea and thermal denaturation are experimentally reversible and independent of the thermal scan rate indicating that all transitions are at equilibrium and the van't Hoff and calorimetric enthalpies obtained from analysis of individual thermal transitions are equivalent demonstrating two‐state character. Global analysis of the urea–temperature phase diagram results in a significantly higher enthalpy of unfolding than obtained from analysis of individual thermal transitions and significant cross correlations describing the urea dependence of
and
that define a complex temperature dependence of the m‐value. Circular dichroism (CD) spectroscopy illustrates a large increase in secondary structure content of the urea‐denatured state as temperature increases and a loss of secondary structure in the thermally denatured state upon addition of urea. These structural changes in the denatured ensemble make up ∼40% of the total ellipticity change indicating a highly compact thermally denatured state. The difference between the thermodynamic parameters obtained from phase diagram analysis and those obtained from analysis of individual thermal transitions illustrates that phase diagrams capture both contributions to unfolding and denatured state expansion and by comparison are able to decipher these contributions.
Sugar nucleotide quantification using multiple reaction monitoring liquid chromatography/tandem mass spectrometry
Authors: Garcia Aldo D. , Chavez Jorge L. , Mechref Yehia
Published: June 2013

RATIONALE

Glycosylation of proteins and lipids is reliant on the availability of monosaccharide‐activated donors known as sugar nucleotides. They are responsible for glycosylation in cells. Reliable quantification of these sugar nucleotides might provide an insight into their biological roles and attributes.

METHODS

Herein, a method is described for the quantification of sugar nucleotides using ultra high pressure liquid chromatography (UHPLC) tandem mass spectrometry, allowing selective detection of sugar nucleotides in a biological sample. Seven model sugar nucleotide standards commonly associated with lipid and protein glycosylation were separated on a porous graphitic carbon column using an UHPLC system coupled to a triple stage quadrupole mass spectrometer utilizing a multiple reaction monitoring approach.

RESULTS

Successful baseline separation of these metabolites was attained in 6 min using an ammonium formate buffer and acetonitrile, circumventing the use of MS‐unfriendly pairing reagents. The linear dynamic range of this procedure was established over almost three orders of magnitude from 20 pg to 1 ng (40 pg to 2 ng for the isomers UDP‐GlcNAc/GalNAc). The limit of detection ranged from 15 pg to 30 pg while the limit of quantification ranged from 50 pg to 100 pg. Furthermore, viability of this method was tested using three different breast cancer cell lines (MDA‐MB‐231, MDA‐MB‐231‐BR, and MDA‐MB‐361) with the successful identification and quantification of all seven targeted sugar nucleotides.

CONCLUSIONS

The described method permitted the quantitative analysis of sugar nucleotides in 10 min, thus allowing the practical use of this approach in high‐throughput settings. The method was also very effective for the quantification of sugar nucleotides derived from three different breast cancer cell lines. The distribution of sugar nucleotides was different among the different cell lines and unique for each cell line. Copyright © 2013 John Wiley & Sons, Ltd.
Local uniformity properties for glauber dynamics on graph colorings
Authors: Hayes Thomas P.
Published: June 2013

We investigate some local properties which hold with high probability for randomly selected colorings of a fixed graph with no short cycles. In a number of related works, establishing these particular properties has been a crucial step towards proving rapid convergence for the single‐site Glauber dynamics, a Markov chain for sampling colorings uniformly at random. For a large class of graphs, this approach yields the most efficient known algorithms for sampling random colorings. © 2013 Wiley Periodicals, Inc. Random Struct. Alg., 2013
Electrochemically controlled detection of adrenaline on poly(2‐aminobenzylamine) thin films by surface plasmon resonance spectroscopy and quartz crystal microbalance
Authors: Chuekachang Sopis , Janmanee Rapiphun , Baba Akira , Phanichphant Sukon , Sriwichai Saengrawee , Shinbo Kazunari , Kato Keizo , Kaneko Futao , Fukuda Nobuko , Ushijima Hirobumi
Published: June 2013

In this study, we present an electrochemically controlled surface plasmon resonance (EC‐SPR) biosensor to detect adrenaline on poly(2‐aminobenzylamine) (P2ABA) thin films. The P2ABA thin films are stable and display electroactivity in a neutral PBS solution. Specific detection of adrenaline was performed on P2ABA thin films because the benzylamine groups in the P2ABA structure could specifically react with adrenalines. Adrenaline was detected in real time by EC‐SPR spectroscopy, which provides an EC‐SPR reflectivity change on the P2ABA thin film upon adrenaline injection. The measured responses were quite different from those for uric acid and ascorbic acid, which are major interferences in adrenaline detection. The electrochemically applied potential facilitates the specific detection of adrenaline. In addition, the detection of adrenaline on the P2ABA thin films was investigated by a quartz crystal microbalance technique. The detection limit for adrenaline at open circuit potential was 10 pM. The present study provides a useful information on the detection of adrenaline on the P2ABA thin films. Copyright © 2013 John Wiley & Sons, Ltd.
Fibroblasts Cultured on Nanowires Exhibit Low Motility, Impaired Cell Division, and DNA Damage
Authors: Persson Henrik , Købler Carsten , Mølhave Kristian , Samuelson Lars , Tegenfeldt Jonas O. , Oredsson Stina , Prinz Christelle N.
Published: June 2013

Nanowires are commonly used as tools for interfacing living cells, acting as biomolecule‐delivery vectors or electrodes. It is generally assumed that the small size of the nanowires ensures a minimal cellular perturbation, yet the effects of nanowires on cell migration and proliferation remain largely unknown. Fibroblast behaviour on vertical nanowire arrays is investigated, and it is shown that cell motility and proliferation rate are reduced on nanowires. Fibroblasts cultured on long nanowires exhibit failed cell division, DNA damage, increased ROS content and respiration. Using focused ion beam milling and scanning electron microscopy, highly curved but intact nuclear membranes are observed, showing no direct contact between the nanowires and the DNA. The nanowires possibly induce cellular stress and high respiration rates, which trigger the formation of ROS, which in turn results in DNA damage. These results are important guidelines to the design and interpretation of experiments involving nanowire‐based transfection and electrical characterization of living cells.
Hypericin-photodynamic therapy leads to interleukin-6 secretion by HepG2 cells and their apoptosis via recruitment of BH3 interacting-domain death agonist and caspases
Authors: Barathan M , Mariappan V , Shankar E M , Abdullah B JJ , Goh K L , Vadivelu J
Published: June 2013

Photodynamic therapy (PDT) has emerged as a capable therapeutic modality for the treatment of cancer. PDT is a targeted cancer therapy that reportedly leads to tumor cell apoptosis and/or necrosis by facilitating the secretion of certain pro-inflammatory cytokines and expression of multiple apoptotic mediators in the tumor microenvironment. In addition, PDT also triggers oxidative stress that directs tumor cell killing and activation of inflammatory responses. However, the cellular and molecular mechanisms underlying the role of PDT in facilitating tumor cell apoptosis remain ambiguous. Here, we investigated the ability of PDT in association with hypericin (HY) to induce tumor cell apoptosis by facilitating the induction of reactive oxygen species (ROS) and secretion of Th1/Th2/Th17 cytokines in human hepatocellular liver carcinoma cell line (HepG2) cells. To discover if any apoptotic mediators were implicated in the enhancement of cell death of HY-PDT-treated tumor cells, selected gene profiling in response to HY-PDT treatment was implemented. Experimental results showed that interleukin (IL)-6 was significantly increased in all HY-PDT-treated cells, especially in 1 μg/ml HY-PDT, resulting in cell death. In addition, quantitative real-time PCR analysis revealed that the expression of apoptotic genes, such as BH3-interacting-domain death agonist (BID), cytochrome complex (CYT-C) and caspases (CASP3, 6, 7, 8 and 9) was remarkably higher in HY-PDT-treated HepG2 cells than the untreated HepG2 cells, entailing that tumor destruction of immune-mediated cell death occurs only in PDT-treated tumor cells. Hence, we showed that HY-PDT treatment induces apoptosis in HepG2 cells by facilitating cytotoxic ROS, and potentially recruits IL-6 and apoptosis mediators, providing additional hints for the existence of alternative mechanisms of anti-tumor immunity in hepatocellular carcinoma, which contribute to long-term suppression of tumor growth following PDT.
Nanoscience for the Conservation of Works of Art
Authors:   Royal Society of Chemistry,   Royal Society of Chemistry
Published: June 2013

Understanding the chemistry behind works of art and heritage materials presents an opportunity to apply scientific techniques to their conservation and restoration. Manipulation of materials at the nanoscale affords greater accuracy and minimal disturbance to the original work, while efficiently combating the affects of time and environment.

This book meets the growing demand for an all-encompassing handbook to instruct on the use of today's science on mankind's cultural heritage. The editors have pioneered modern techniques in art conservation over the last four decades, and have brought together expertise from across the globe. Each chapter presents the theoretical background to the topic in question, followed by practical information on its application and relevant case studies.

Introductory chapters present the science behind the physical composition of art materials. Four chapters explore various cleaning techniques now, followed by four chapters describing the application of inorganic nanomaterials. Each chapter is fully referenced to the primary literature and offers suggestions for further reading.

Professional conservators and scientists alike will find this essential reading, as will postgraduate students in the fields of materials and colloid science, art restoration and nanoscience.
Cleaning III: Applications and Case Studies
Authors: Giorgi R. , Carretti E.
Published: June 2013

Nanostructured fluids, such as micellar solutions and microemulsions, have in recent decades opened new perspectives in the field of cleaning and dirt removal from the surfaces of artworks. Selectivity, high efficiency and environmental impact have been radically optimized thanks to the synergistic action of different detergent mechanisms. Solubilization together with emulsification and the direct interactions of surfactants with the artwork surfaces allow the complete swelling and removal of materials that cannot be removed by classical cleaning methods. This is confirmed by the challenging problem of the removal of aged adhesives; upon ageing adhesives exhibit a strong decrease in solubility due to cross-linking reactions and the increase of molecular weight. Since the beginning of the 1990s, successful applications of oil-in-water microemulsions for the removal of polymer coatings from wall paintings have been documented.
Cleaning IV: Gels and Polymeric Dispersions
Authors: Fratini E. , Carretti E.
Published: June 2013

This chapter provides an overview of a complex and variegated class of material, namely gels. The objective of this chapter is to introduce the reader to a basic knowledge of gels and principally to the difference between physical and chemical gels. Structural and mechanical properties are introduced in order to provide the basis for a sufficient comprehension of the uses and applications of this class of materials in the conservation of Cultural Heritage. Finally, standard as well as advanced characterization techniques are reported.
Inorganic Nanomaterials: Synthesis and Properties
Authors: Bonini M. , Baglioni P. , Chelazzi D.
Published: June 2013

This chapter describes the properties of inorganic nanomaterials and the most common methods used to prepare them. The peculiar characteristics of materials when their dimensions are reduced to the nanoscale are briefly introduced. Top-down and bottom-up preparation methods are critically reviewed, with a special focus on those strategies that are most frequently used in the preparation of nanostructures for the conservation of cultural heritage.
Biomineralization, Geopolymers and Hybrid Nanocomposites
Authors: Dei L. , Chelazzi D.
Published: June 2013

This chapter is dedicated to considering very peculiar nanotechnological systems, some of which are at present rather far from suitable applications in cultural heritage conservation; nevertheless they present interesting potential as new materials for art/architecture preservation. We will focus on biomineralization processes, where biological activity is used to consolidate stone materials thanks to the crystallization of calcium carbonate induced by microorganisms. It is interesting to underline that these methods have already originated important applications in cultural heritage conservation, and the literature shows that practical assessment is at a good stage. Concerning the other two subjects of the present chapter – geopolymers and organic–inorganic hybrid nanocomposites – the main chemical and physico-structural properties will be analysed in order to investigate possible applications in cultural heritage conservation, namely in the field of preservation and restoration of works of art/architecture, and in climate and environmental control.
Exploring novel strategies for AIDS protozoal pathogens: α-helix mimetics targeting a key allosteric protein–protein interaction in C. hominis thymidylate synthase-dihydrofolate reductase (TS-DHFR)
Authors: Martucci W. Edward , Rodriguez Johanna M. , Vargo Melissa A. , Marr Matthew , Hamilton Andrew D. , Anderson Karen S.
Published: June 2013

The bifunctional enzyme TS–DHFR from Cryptosporidium hominis is a molecular target for design of antiparasitic therapies for AIDS-related opportunistic infections.
Wideband printed slot antenna with polarisation diversity
Authors: Xie J.‐J. , Yin Y.‐Z. , Chen Y.
Published: June 2013

A single‐layer wideband printed slot antenna with polarisation diversity is presented using a hybrid feeding technique. The antenna consists of an aperture‐coupled feeding element and a coplanar waveguide feeding element. The aperture‐coupled microstrip feed line with a 180° phase difference is used to reduce the cross‐polarisation level and improve the isolation level. A circular patch is connected to the coplanar waveguide feed line for good impedance matching. By introducing a fan‐shaped slot to separate the ground plane of the radiating elements, the measured isolation between the two feeding ports is better than 30 dB in the whole operating band. The measured −10 dB impedance bandwidths are 49% (4.72–7.75 GHz) and 63% (3.96–7.64 GHz) at port 1 and port 2, respectively. Moreover, the proposed antenna has a compact structure and stable gain over the operating band; thus it can be used in the 5.2/5.8 GHz WLAN and 5.5 GHz WiMAX systems.
Quint‐band branch‐line coupler with open‐ and short‐circuited stubs
Authors: Tang C.W. , Lan P.G. , Tseng C.T.
Published: June 2013

A branch‐line coupler with five operating frequencies is presented. A conventional branch‐line coupler and four shunted reactances are adopted for the proposed quint‐band branch‐line coupler. Detailed formulas are analytically derived and experimentally tested for the proposed quint‐band branch‐line coupler. Moreover, both simulated and measured results are included to validate the proposed coupler.
Adaptive correlation algorithm for aligning antenna arrays in deep space communication
Authors: Bai Y.‐F. , Wang X.‐H. , Gao C.‐J. , Huang Q.‐L. , Shi X.‐W.
Published: June 2013

Instead of using large apertures, antenna arrays can be used to enhance the receiving signal‐to‐noise ratio in deep space applications. An adaptive correlation algorithm is presented. This method is a variable step‐size algorithm based on a sigmoid function, which not only uses the cross‐correlation of each antenna with the reference one but also utilises the variance of weight updating values from every iteration. The simulation results demonstrate that the proposed algorithm can achieve low combining loss for very weak signals after a few iterations.
Fusion for visual context enhancement using intensity transformation function of infrared images
Authors: Jiao L.‐C. , Tang Q.‐X.
Published: June 2013

An intensity transformation function of infrared images is presented and used for context enhancement of visual images, upon which a new image fusion method in the shift‐invariant wavelet domain is developed. The function behaves like a sigmoid function and shifts and expands the range of dark pixels of infrared images. These adjustments can avoid artificial bright pixels introduced in the later enhancing of visual images and the bleaching effect in the final fused images owing to the exponential map of very dark pixels of the infrared images. Experimental results validate the subjective performance of the proposed method, along with objective performance through several suggested quantitative metrics.
Switching operation improvement of phase change memory with nanoscale W plug structure by CMP process
Authors: Li Ying , Song Zhitang , Liu Bo , Wu Guanping , Feng Songlin
Published: June 2013

To reduce the reset current for developing reliable high‐density phase change random access memory, small bottom electrode contact (BEC) size formation is a critical process. One of the failure modes for the process is the corrosion of the tungsten (W) plug, which is caused by the W chemical mechanical polisher (CMP) process. An ultra‐smooth surface of BEC nanoscale W plug structure was successfully fabricated by the CMP process, which reduced the W/phase change material (Ge2Sb2Te5, GST) contact resistance, and gained more homogeneous resistance distribution. Thus, the stability of the device was improved greatly by the acidic buff CMP process compared with that of the device with alkali buff owing to the reduction of W/GST connect resistance fluctuation.
Fully passivated radial junction nanowire silicon solar cells with submerged nickel‐silicide contact for efficiency enhancement
Authors: Ren R. , Guo Y.X. , Wang J. , Zhu R.H.
Published: June 2013

Presented is a silicon solar cell model with fully passivated radial junction nanowire surface decoration and submerged nickel‐silicide contact. Numerical simulations using a finite‐difference time‐domain method have been done to investigate the spectral responses of the solar cell model. The experimental results indicate that, with proper nickel‐silicide thickness, the fill factor of the cell can be improved considerably without much degradation on short circuit current density. Under AM 1.5G illumination, the silicon nanowire solar cell device with 50 Å nickel‐silicide contact has short circuit current density of 26.3 mA/cm2, open circuit voltage of 586 mV and fill factor of 70.0%, contributing to power conversion efficiency of 10.8%, which is 19% higher than the control device without the nickel‐silicide contact.
Investigation of multiwall carbon nanotube‐based nanofluid advantages in microchannel heat sinks
Authors: Kamali Reza , Jalali Yaghoub , Binesh Alireza R.
Published: June 2013

In this Letter, the cooling performance of microchannel heat sinks, as well as a comparison of the heat the transfer efficiency of two nanofluids: Al2O3–water and multiwall carbon nanotube (MWCNT)–water and pure water, is investigated. At first, the same pumping power inlet boundary condition, which is a standard comparison of the performance of different fluids, is applied for a single rectangular duct, and the results are stored for the modelling of the heat sink. Following this stage, a heat sink made up of aluminium with water as working fluid is modelled. After validation of the results and optimisation of the grid, the efficiency of the three fluids is compared. It is seen that by using MWCNT–water nanofluid instead of water in a typical heat sink, the mean reduction in thermal resistance for MWCNT–water and Al2O3–water, in comparison with using water, respectively, are 18 and 1%. This shows the great advantages of using MWCNTs in heat sinks in comparison with Al2O3.
Preparation and characterisation of multifunctional magnetic‐fluorescent Fe3O4/carbon dots/silica composites
Authors: Ma Yu‐jie , Liu Yun , Zhou Xue‐hua , Liu Chun‐yan
Published: June 2013

Mesoporous Fe3O4/carbon dots (CDs)/silica microspheres with large surface area, good fluorescence and magnetic property have been synthesised with as‐prepared Fe3O4 nanoparticles, silane‐functionalised CDs and tetraethyl orthosilicate as co‐precursors and cetyltrimethyl ammonium bromide as the pore‐directing agent. Because of their good blue fluorescence, magnetic property and large surface areas, these particles were found to have potential in bimodal cellular imaging, drug delivery, molecular targeting and as building blocks for the assembly of complex nanostructures.
Investigation on bacterial adhesion and colonisation resistance over laser‐machined micro patterned surfaces
Authors: Chebolu Aneissha , Laha Bhakti , Ghosh Monidipa , Nagahanumaiah
Published: June 2013

Micro–nano patterns created directly over solid surfaces to combat microbial activity help in preventing hospital‐acquired infections. This Letter is focused on defining surface topologies by laser patterning over solid surfaces. Studies on designing surface topologies and bacterial culture have been carried out and the feasibility of micro scale features in restricting bacterial growth has been investigated. The effects of the engineered roughness index and contact angle are discussed. Contact angle measurement over patterned surfaces using a novel computer vision‐based technique is demonstrated and the effect of contact angle on bacterial adhesion has been presented. The results obtained show that the designed micro scale geometries can effectively reduce the growth of bacteria on the said surfaces.
Synthesis and electrical properties of p‐type CdTe nanowires
Authors: Li Shanying , Li Xiaoyan , Zhao Haipeng
Published: June 2013

CdTe nanowires (NWs) are synthesised via a thermal evaporation process, and the structure characterisations reveal that the as‐synthesised NWs are single crystalline with a zinc blende structure and a crystal growth direction of [111]. Nano‐field‐effect transistors are fabricated based on individual CdTe NWs, and the electrical properties demonstrate that the CdTe NWs have p‐type conductivity with a mobility (μh) of 6.8 × 10− 2 cm2V− 1S− 1 and carrier concentration (nh) about 3.6 × 1019 cm− 3. This significant p‐type conductivity is attributed to the intrinsic defects of Cd vacancies in NWs, and then, the high‐aspect ratio and nearly perfect single‐crystalline quality in one‐dimensional NWs are conducive to excellent electron transfer characteristics. The synthesised NWs with significant p‐type conductivity will be very attractive candidates for nanoelectronic devices.
Finite-size scaling investigation of the liquid-liquid critical point in ST2 water and its stability with respect to crystallization
Authors: Kesselring T. A. , Lascaris E. , Franzese G. , Buldyrev S. V. , Herrmann H. J. , Stanley H. E.
Published: June 2013

The liquid-liquid critical point scenario of water hypothesizes the existence of two metastable liquid phases—low-density liquid (LDL) and high-density liquid (HDL)—deep within the supercooled region. The hypothesis originates from computer simulations of the ST2 water model, but the stability of the LDL phase with respect to the crystal is still being debated. We simulate supercooled ST2 water at constant pressure, constant temperature, and constant number of molecules N for N ⩽ 729 and times up to 1 μs. We observe clear differences between the two liquids, both structural and dynamical. Using several methods, including finite-size scaling, we confirm the presence of a liquid-liquid phase transition ending in a critical point. We find that the LDL is stable with respect to the crystal in 98% of our runs (we perform 372 runs for LDL or LDL-like states), and in 100% of our runs for the two largest system sizes (N = 512 and 729, for which we perform 136 runs for LDL or LDL-like states). In all these runs, tiny crystallites grow and then melt within 1 μs. Only for N ⩽ 343 we observe six events (over 236 runs for LDL or LDL-like states) of spontaneous crystallization after crystallites reach an estimated critical size of about 70 ± 10 molecules.
Fabrication and characterization of the source grating for visibility improvement of neutron phase imaging with gratings
Authors: Kim Jongyul , Lee Kye Hong , Lim Chang Hwy , Kim Taejoo , Ahn Chi Won , Cho Gyuseong , Lee Seung Wook
Published: June 2013

The fabrication of gratings including metal deposition processes for highly neutron absorbing lines is a critical issue to achieve a good visibility of the grating-based phase imaging system. The source grating for a neutron Talbot-Lau interferometer is an array of Gadolinium (Gd) structures that are generally made by sputtering, photo-lithography, and chemical wet etching. However, it is very challenging to fabricate a Gd structure with sufficient neutron attenuation of approximately more than 20 μm using a conventional metal deposition method because of the slow Gd deposition rate, film stress, high material cost, and so on. In this article, we fabricated the source gratings for neutron Talbot-Lau interferometers by filling the silicon structure with Gadox particles. The new fabrication method allowed us a very stable and efficient way to achieve a much higher Gadox filled structure than a Gd film structure, and is even more suitable for thermal polychromatic neutrons, which are more difficult to stop than cold neutrons. The newly fabricated source gratings were tested at the polychromatic thermal neutron grating interferometer system of HANARO at the Korea Atomic Energy Research Institute, and the visibilities and images from the neutron phase imaging system with the new source gratings were compared with those fabricated by a Gd deposition method.
Diradical character dependences of the first and second hyperpolarizabilities of asymmetric open-shell singlet systems
Authors: Nakano Masayoshi , Champagne Benoît
Published: June 2013

The static first and second hyperpolarizabilities (referred to as β and γ, respectively) of asymmetric open-shell singlet systems have been investigated using the asymmetric two-site diradical model within the valence configuration interaction level of theory in order to reveal the effect of the asymmetric electron distribution on the diradical character and subsequently on β and γ. It is found that the increase of the asymmetric electron distribution causes remarkable changes in the amplitude and the sign of β and γ, and that their variations are intensified with the increase of the diradical character. These results demonstrate that the asymmetric open-shell singlet systems with intermediate diradical characters can exhibit further enhancements of β and γ as compared to conventional asymmetric closed-shell systems and also to symmetric open-shell singlet systems with intermediate diradical characters.
Ligand field parameters and the ground state of Fe(II) phthalocyanine
Authors: Kuz'min M. D. , Savoyant A. , Hayn R.
Published: June 2013

A judicious analysis of previously published experimental data leads one to conclude that the ground state of iron(II) phthalocyanine is an orbitally degenerate spin triplet \documentclass[12pt]{minimal}\begin{document}$a_{1g}^2 e_g^{\uparrow \downarrow \uparrow } b_{2g}^{\uparrow }$\end{document}a1g2eg↑↓↑b2g↑ (3Eg). The ligand field parameters, in relation to Racah's C, are approximately as follows: B20/C = 0.84, B40/C = 0.0074. The uniqueness of this result is demonstrated by means of a special diagram in the B20/C − B40/C plane (under additional conditions that B44/B40 = 35/3 and B/C = 0.227). The system is in a strong-ligand-field regime, which enables the use of single-determinant techniques corrected for correlations within the 3d shell of Fe.
Elastic properties of compressed cryocrystals in a deformed atom model
Authors: Gorbenko Ie. Ie. , Zhikharev I. V. , Troitskaya E. P. , Chabanenko Val. V. , Pilipenko E. A.
Published: June 2013

A model with deformed atom shells was built to investigate the elastic properties of rare-gas Ne and Kr crystals under high pressure. It is shown that the observed deviation from the Cauchy relation δ cannot be adequately reproduced when taking into account only the many-body interaction. The individual pressure dependence of δ is the result of competition of the many-body interaction and the quadrupole interaction associated with the quadrupole-type deformation of electron shells of the atoms during the displacement of the nuclei. Each kind of interaction makes a strongly pressure dependent contribution to δ. In the case of Ne and Kr, contributions of these interactions are compensated to a good precision, providing δ being almost constant against pressure.
Kinetics of nucleation during the bcc-hcp structural transition in solid helium
Authors: Birchenko A. P. , Vekhov Ye. O. , Mikhin N. P. , Rudavskii E. Ya. , Baidakov V. G.
Published: June 2013

The nucleation kinetics of the hcp phase in the supercooled bcc phase of solid 4He and a 3He-4He solution containing 1% 3He is studied experimentally. Precision measurements of the pressure in the crystal are made as it is cooled along an isochore near the bcc-hcp phase equilibrium curve. The lifetime of the metastable bcc phase in 4He is found to have a complicated dependence on the level of supercooling which can be described in terms of two nucleation mechanisms—homogeneous and heterogeneous. The homogeneous mechanism occurs for the highly supercooled bcc phase in carefully annealed crystals, while the heterogeneous mechanism, for which the activation coefficients are several orders of magnitude lower than for the homogeneous mechanism, occurs with low supercooling. The influence of defects and impurities on the nucleation process is also studied. In unannealed (defective) 4He crystals the nucleation rate is found to have an enormous scatter, which is indicative of poor reproducibility from one crystal to another. For annealed samples of 3He-4He solution the nucleation kinetics data can be described only by the heterogeneous nucleation mechanism.
The structure of SrTiO3(001)-2 × 1 surface analyzed by high-resolution medium energy ion scattering coupled with ab initio calculations
Authors: Matsuda Taishi , Yoshida Yuki , Mitsuhara Kei , Kido Yoshiaki
Published: June 2013

High-resolution medium energy ion scattering (MEIS) spectrometry coupled with photoelectron spectroscopy revealed unambiguously that the initial SrTiO3(001) surface chemically etched in a buffered NH4F-HF solution was perfectly terminated with a single-layer (SL) of TiO2(001) and annealing the surface at 600–800 ºC in ultrahigh vacuum (UHV) led to a (2 × 1)-reconstructed surface terminated with a double-layer (DL) of TiO2(001). After annealing in UHV, rock-salt SrO(001) clusters with two atomic layer height grew epitaxially on the DL-TiO2(001)-2 × 1 surface with a coverage of 20%–30%. High-resolution MEIS in connection with ab initio calculations demonstrated the structure of the DL-TiO2(001)-2 × 1 surface close to that proposed by Erdman et al. [Nature (London) 419, 55 (2002)]10.1038/nature01010 rather than that predicted by Herger et al. [Phys. Rev. Lett. 98, 076102 (2007)]10.1103/PhysRevLett.98.076102. Based on the MEIS analysis combined with the ab initio calculations, we propose the most probable (2 × 1) surface structure.
Improved expanding ring technique for determining dynamic material properties
Authors: Liang M. Z. , Li X. Y. , Qin J. G. , Lu F. Y.
Published: June 2013

An improved expanding ring experimental technique has been described to determine dynamic material properties under conditions approximating uniform one-dimensional tensile loading. There are mainly explosive expanding ring technique and electromagnetic expanding ring technique currently, for which exist many limitations in practical applications. The work reported herein is an attempt to overcome this difficulty by lateral efficiency loading produced by projectile, made of low-density material, impacting the same material filling. The lateral efficiency loading is a convenient and effective method, which allows materials to be in uniform uniaxial stress conditions at a high stress rate. The procedure is illustrated by experiments performed on 1100-0 aluminum rings.
The role of graphene in enhancing the stiffness of polymeric material: A molecular modeling approach
Authors: Rahman R.
Published: June 2013

Amorphous epoxy is considered for investigating the role of graphene in enhancing elastic stiffness of polymers. Graphene is incorporated in the amorphous epoxy in order to develop graphene-epoxy systems. The mechanical properties of crosslinked graphene-epoxy (G-Ep) nanocomposites have been investigated using molecular mechanics (MM) and molecular dynamics (MD) simulations. The influences of graphene nanoplatelet weight concentrations, aspect ratios, and dispersion on elastic constants were studied. Both randomly oriented and stacked graphene-epoxy nanocomposites were considered. A polymer consistent force field (pcff) was used in the analysis. The G-Ep nanocomposites system underwent MD equilibration followed by uniform deformation. The stress-strain responses were evaluated in order to determine Young's modulus. MM simulation was also used to calculate the Young's modulus and shear modulus at 0 K. The results from MD and MM simulation showed reasonable improvement in Young's modulus and shear modulus for G-Ep system in comparison to neat epoxy resin. The graphene concentrations in the range of 1%-3% and graphene with high aspect ratio are seen to improve the Young's modulus by 82% approximately. The results from the simulations were compared with the results from micromechanics based analysis and nanoindentation tests. It was observed from both the atomistic scale simulation and nanoindentation tests that incorporation of graphene in neat epoxy at low weight concentration improves the elastic properties. Using similar MD scheme, it was also seen that the dispersed graphene-epoxy system possesses enhanced in-plane elastic modulus compared to the agglomerated graphene-epoxy system.
Local structure of amorphous GaN1−xAsx semiconductor alloys across the composition range
Authors: Levander A. X. , Yu K. M. , Novikov S. V. , Liliental-Weber Z. , Foxon C. T. , Dubon O. D. , Wu J. , Walukiewicz W.
Published: June 2013

Typically only dilute (up to ∼10%) highly mismatched alloys can be grown due to the large differences in atomic size and electronegativity of the host and the alloying elements. We have overcome the miscibility gap of the GaN1−xAsx system using low temperature molecular beam epitaxy. In the intermediate composition range (0.10 < x < 0.75), the resulting alloys are amorphous. To gain a better understanding of the amorphous structure, the local environment of the As and Ga atoms was investigated using extended x-ray absorption fine structure (EXAFS). The EXAFS analysis shows a high concentration of dangling bonds compared to the crystalline binary endpoint compounds of the alloy system. The disorder parameter was larger for amorphous films compared to crystalline references, but comparable with other amorphous semiconductors. By examining the Ga local environment, the dangling bond density and disorder associated with As-related and N-related bonds could be decoupled. The N-related bonds had a lower dangling bond density and lower disorder.
Dynamics of ultra-intense circularly polarized solitons under inhomogeneous plasmas
Authors: Wu Dong , Zheng C. Y. , He X. T.
Published: June 2013

The dynamics of the ultra-intense circularly polarized solitons under inhomogeneous plasmas are examined. The interaction is modeled by the Maxwell and relativistic hydrodynamic equations and is solved with fully implicit energy-conserving numerical scheme. The soliton is self-consistently generated by the interaction between laser and plasma on the vacuum-plasma interface, and the generation mechanism is well confirmed by two dimensional particle-in-cell simulation. It is shown that a propagating weak soliton can be decreased and reflected by increasing plasma background, which is consistent with the existing studies based on hypothesis of weak density response. However, it is found that ultra-intense soliton is well trapped and kept still when encountering increasing background. Probably, this founding can be applied for trapping and amplifying high-intensity laser-fields.
Theoretical investigation on the magnetocaloric effect in amorphous systems, application to: Gd80Au20 and Gd70Ni30
Authors: Nóbrega E. P. , Caldas A. , Ribeiro P. O. , Alho B. P. , Alvarenga T. S. T. , de Sousa V. S. R. , de Oliveira N. A. , von Ranke P. J.
Published: June 2013

The temperature dependence of the magnetocaloric effect in Gd80Au20 and Gd70Ni30 amorphous alloys were investigated, using the Handrich-Kobe model with a modified Brillouin function that takes an additional exchange fluctuation term. The exchange fluctuation parameters were determined to give better fits to magnetic entropy changes and adiabatic temperature changes. The magnetic entropy changes of 2.20 Jmol−1K−1 and 1.50 Jmol−1K−1 and the refrigerant capacity values of 135 Jmol−1 (ΔB=5 T) and 146 Jmol−1 (ΔB=7 T) are obtained for Gd80Au20 and Gd70Ni30, respectively. In addition, the influence of phase changes between crystalline and amorphous states on the isothermal entropy change was investigated.
Broadband absorption enhancement of organic solar cells with interstitial lattice patterned metal nanoparticles
Authors: Chen Luzhou , Choy Wallace C. H. , Sha Wei E. I.
Published: June 2013

Light blocking induced by top patterned nanostructures is a fundamental limit in solar cells absorption. Here we propose an interstitial lattice patterned organic solar cell which can improve the light blocking of traditional square lattice and achieve broadband absorption enhancement. Compared to square lattice design, the plasmonic mode couplings between individual metallic nanoparticles in the interstitial lattice are more versatile and much stronger. Moreover, plasmonic modes can couple to the guided modes, resulting in large enhancement factor at some wavelengths. The interstitial lattice concept will be a broad interest and great help for high-performance photovoltaics.
Advanced high-k dielectric amorphous LaGdO3 based high density metal-insulator-metal capacitors with sub-nanometer capacitance equivalent thickness
Authors: Pavunny S. P. , Misra P. , Scott J. F. , Katiyar R. S.
Published: June 2013

Planar metal-insulator-metal (MIM) mono-dielectric layer stacks were fabricated using pulsed laser deposited thin films of high-k dielectric LaGdO3. These stacks showed high capacitance density ∼43.5 fF/μm2 with sub-nanometer capacitance equivalent thicknesses of ∼0.66 nm, large breakdown field of ∼6 MV/cm, greater energy storage density of ∼40 J/cm3, smaller voltage coefficient of capacitance, and lower dependence of it on layer thickness α ∝ d−1 and frequency. All these features make LaGdO3 a material of interest for next generation MIM structures for radio frequency, analog/mixed-signal, and dynamic random access memory applications.