bluuebunny/crossref_metadata_2025 huggingface dataset:
A conserved histidine in switch-II of EF-G moderates release of inorganic phosphate
Authors: Koripella Ravi Kiran , Holm Mikael , Dourado Daniel , Mandava Chandra Sekhar , Flores Samuel , Sanyal Suparna
Published: August 2015

Elongation factor G (EF-G), a translational GTPase responsible for tRNA-mRNA translocation possesses a conserved histidine (H91 in Escherichia coli) at the apex of switch-II, which has been implicated in GTPase activation and GTP hydrolysis. While H91A, H91R and H91E mutants showed different degrees of defect in ribosome associated GTP hydrolysis, H91Q behaved like the WT. However, all these mutants, including H91Q, are much more defective in inorganic phosphate (Pi) release, thereby suggesting that H91 facilitates Pi release. In crystal structures of the ribosome bound EF-G•GTP a tight coupling between H91 and the γ-phosphate of GTP can be seen. Following GTP hydrolysis, H91 flips ~140° in the opposite direction, probably with Pi still coupled to it. This, we suggest, promotes Pi to detach from GDP and reach the inter-domain space of EF-G, which constitutes an exit path for the Pi. Molecular dynamics simulations are consistent with this hypothesis and demonstrate a vital role of an Mg2+ ion in the process.
Deletion of the tyrosine phosphatase Shp2 in Sertoli cells causes infertility in mice
Authors: Hu Xiaopeng , Tang Zhenzhou , Li Yang , Liu Wensheng , Zhang Shuang , Wang Bingyan , Tian Yingpu , Zhao Yinan , Ran Hao , Liu Wenjie , Feng Gen-Sheng , Shuai Jianwei , Wang Haibin , Lu Zhongxian
Published: August 2015

The male’s ability to reproduce is completely dependent on Sertoli cells. However, the mechanisms governing the functional integrity of Sertoli cells have remained largely unexplored. Here, we demonstrate that deletion of Shp2 in Sertoli cells results in infertility in mice. In Shp2 knockout mice (SCSKO), a normal population of Sertoli cells was observed, but the blood-testis barrier (BTB) was not formed. Shp2 ablation initiated the untimely and excessive differentiation of spermatogonial stem cells (SSCs) by disturbing the expression of paracrine factors. As a consequence, the process of spermatogenesis was disrupted and the germ cells were depleted. Furthermore, Shp2 deletion impaired the cell junctions of the primary Sertoli cells and failed to support the clonal formation of SSCs co-cultured with SCSKO Sertoli cells. As expected, Shp2 restoration largely restores the cell junctions of the primary Sertoli cells and the clonal formation of SSCs. To identify the underlying mechanism, we further demonstrated that the absence of Shp2 suppressed Erk phosphorylation and thus, the expression of follicle-stimulating hormone (FSH)- and testosterone-induced target genes. These results collectively suggest that Shp2 is a critical signaling protein that is required to maintain Sertoli cell function and could serve as a novel target for male infertility therapies.
Rhus coriaria induces senescence and autophagic cell death in breast cancer cells through a mechanism involving p38 and ERK1/2 activation
Authors: El Hasasna Hussain , Athamneh Khawlah , Al Samri Halima , Karuvantevida Noushad , Al Dhaheri Yusra , Hisaindee Soleiman , Ramadan Gaber , Al Tamimi Nedaa , AbuQamar Synan , Eid Ali , Iratni Rabah
Published: August 2015

Here, we investigated the anticancer effect of Rhus coriaria on three breast cancer cell lines. We demonstrated that Rhus coriaria ethanolic extract (RCE) inhibits the proliferation of these cell lines in a time- and concentration-dependent manner. RCE induced senescence and cell cycle arrest at G1 phase. These changes were concomitant with upregulation of p21, downregulation of cyclin D1, p27, PCNA, c-myc, phospho-RB and expression of senescence-associated β-galactosidase activity. No proliferative recovery was detected after RCE removal. Annexin V staining and PARP cleavage analysis revealed a minimal induction of apoptosis in MDA-MB-231 cells. Electron microscopy revealed the presence of autophagic vacuoles in RCE-treated cells. Interestingly, blocking autophagy by 3-methyladenine (3-MA) or chloroquine (CQ) reduced RCE-induced cell death and senescence. RCE was also found to activate p38 and ERK1/2 signaling pathways which coincided with induction of autophagy. Furthermore, we found that while both autophagy inhibitors abolished p38 phosphorylation, only CQ led to significant decrease in pERK1/2. Finally, RCE induced DNA damage and reduced mutant p53, two events that preceded autophagy. Our findings provide strong evidence that R. coriaria possesses strong anti-breast cancer activity through induction of senescence and autophagic cell death, making it a promising alternative or adjunct therapeutic candidate against breast cancer.
Two single amino acid substitutions in the intervening region of Newcastle disease virus HN protein attenuate viral replication and pathogenicity
Authors: Liu Bin , Ji Yanhong , Lin Zhongqing , Fu Yuguang , Muhammad Dafallah Rihab , Zhu Qiyun
Published: August 2015

Among the proteins encoded by Newcastle disease virus (NDV), the attachment protein (HN) is an important determinant of virulence and pathogenicity. HN has been molecularly characterized at the protein level; however, the relationship between the molecular character of HN and the animal pathotype it causes has not been well explored. Here, we revisited the intervening region (IR) of the HN stalk and extended the known biological functions of HN. Three distinct substitutions (A89Q, P93A and L94A) in the IR of genotype VII NDV (G7 strain) HN protein were analyzed. The A89Q and L94A mutations weakened the fusion promotion activity of HN to 44% and 41% of that of wild type, respectively, whereas P93A decreased the neuraminidase activity to 21% of the parental level. At the virus level, P93A and L94A-bearing viruses displayed impaired receptor recognition ability, neuraminidase activity and fusion-promoting activity, all of which led to virus attenuation. In addition, the L94A-mutated virus showed a dramatic decline in replication and was attenuated in cells and in chickens. Our data demonstrate that the HN biological activities and functions modulated by these specific amino acids in the IR are associated with NDV replication and pathogenicity.
Tomographic reconstruction of ionospheric electron density during the storm of 5-6 August 2011 using multi-source data
Authors: Tang Jun , Yao Yibin , Zhang Liang , Kong Jian
Published: August 2015

The insufficiency of data is the essential reason for ill-posed problem existed in computerized ionospheric tomography (CIT) technique. Therefore, the method of integrating multi-source data is proposed. Currently, the multiple satellite navigation systems and various ionospheric observing instruments provide abundant data which can be employed to reconstruct ionospheric electron density (IED). In order to improve the vertical resolution of IED, we do research on IED reconstruction by integration of ground-based GPS data, occultation data from the LEO satellite, satellite altimetry data from Jason-1 and Jason-2 and ionosonde data. We used the CIT results to compare with incoherent scatter radar (ISR) observations and found that the multi-source data fusion was effective and reliable to reconstruct electron density, showing its superiority than CIT with GPS data alone.
Lung Cancer Onset in Wild Type Mice Following Bone Marrow Reconstitution with krasv12 Cells
Authors: Belloni Elena , Martin Padura Ines , Gerbino Elvira , Orecchioni Stefania , Fusar Imperatore Fulvia , Marighetti Paola , Bertalot Giovanni , Giuseppe Pelicci Pier , Bertolini Francesco
Published: August 2015

A role for bone-marrow-derived cells (BMDCs) in tissue repair and malignancy onset has been proposed, but their contribution is still debated. We tested the ability of BMDCs containing the inducible krasV12 oncogene to initiate lung adenocarcinoma. For our experimental strategy, we reconstituted lethally irradiated wild type mice with BMDCs carrying inducible krasV12 and subsequently induced oncogene expression by 4-OHT administration. Epithelial lung lesions, from adenoma to adenocarcinomas, appeared at successive time points. These results show that lung tumors were derived from donor BMDCs and indicate a direct involvement of bone marrow cells in the development of epithelial cancers.
A novel photoelectrochemical aptasensor based on the modulation of a dye sensitized TiO2 photoelectrode
Authors: Wang Kewei , Xu Lijun , Sun Na , Wang Zhili , Hong Shanni , Wang Jine , Liu Min , Pei Renjun
Published: August 2015

Both N719 dye labeled chain release and bound thrombin blocking electron transfer resulted in a decreased photocurrent.
A fluorescence immunochromatographic assay for rapid and sensitive detection of human prealbumin in serum
Authors: Yang Yajie , Li Chaohui , Wang Wei , Dong Tingting , Xiong Yonghua , Shen Jun , Lai Weihua
Published: August 2015

Schematic of the sandwich FMs-LFIA test strip.
Phosphorus-doped CoS2 nanosheet arrays as ultra-efficient electrocatalysts for the hydrogen evolution reaction
Authors: Ouyang Canbin , Wang Xin , Wang Shuangyin
Published: August 2015

P doped CoS2 nanosheet arrays were prepared by a two-step reaction at lower temperature. P doped CoS2, as a highly efficient HER catalyst, shows lower onset potential, smaller Tafel slope and better catalytic stability than pure CoS2.
Accessing conjugated polymers with precisely controlled heterobisfunctional chain ends via post-polymerization modification of the OTf group and controlled Pd(0)/t-Bu3P-catalyzed Suzuki cross-coupling polymerization
Authors: Zhang Hong-Hai , Hu Qiao-Sheng , Hong Kunlun
Published: August 2015

Accessing of conjugated polymers with precisely controlled heterobisfunctional chain ends was achieved via the post-polymerization modification of the triflate (OTf) group.
N-Substitution dependent stereoselectivity switch in palladium catalyzed hydroalkynylation of ynamides: a regio and stereoselective synthesis of ynenamides
Authors: Dwivedi Vikas , Hari Babu Madala , Kant Ruchir , Sridhar Reddy Maddi
Published: August 2015

A palladium catalysed regioselective hydroalkynylation of ynamides for ynenamides is achieved with an N-substitution dependent stereoselectivity switch.
KF-mediated controlled-synthesis of potassium ytterbium fluorides (doped with Er3+) with phase-dependent upconversion luminescence
Authors: Ding Mingye , Zhu Fei , Ma Danyang , Huang Xiaoyong , Liu Peng , Song Kaixin , Zhong Jiasong , Xi Junhua , Ji Zhenguo , Chen Daqin
Published: August 2015

Potassium ytterbium fluorides with predictable crystal phases and architectures have been successfully synthesized by simply tuning the molar ratio of KF to Yb3+via a facile and general solution-based approach.
Theoretical study on the dehydrogenation reaction of dihydrogen bonded phenol–borane-trimethylamine in the excited state
Authors: Yang Yonggang , Liu Yufang , Yang Dapeng , Li Hui , Jiang Kai , Sun Jinfeng
Published: August 2015

No dehydrogenation reaction occurs in the ground state of dihydrogen bonded phenol–BTMA. TS-S10 points to the formation of a hydrogen molecule, while TS-S11 points to the B atom. The dehydrogenation reaction along TS-S10 is energy favorable, unlike that along TS-S11.
The heavy atom effect on Zn(ii) phthalocyanine derivatives: a theoretical exploration of the photophysical properties
Authors: Alberto Marta E. , De Simone Bruna C. , Mazzone Gloria , Sicilia Emilia , Russo Nino
Published: August 2015

Absorption electronic spectra, singlet–triplet energy gaps and spin–orbit matrix elements have been computed at DFT and TDDFT levels of theory for a series of substituted Zn(ii)-phthalocyanines (ZnPcs), recently proposed as potential photosensitizers in photodynamic therapy (PDT).
VOPO4·2H2O encapsulated in graphene oxide as a heterogeneous catalyst for selective hydroxylation of benzene to phenol
Authors: Borah Parijat , Datta Arunabha , Nguyen Kim Truc , Zhao Yanli
Published: August 2015

A heterogeneous catalyst was prepared through a strong interaction between graphene oxide and exfoliated VOPO4·2H2O, which can oxidize benzene to phenol with 100% selectivity and 33% conversion up to 5 catalytic cycles.
All-polymer photonic sensing platform based on whispering-gallery mode microgoblet lasers
Authors: Wienhold T. , Kraemmer S. , Wondimu S. F. , Siegle T. , Bog U. , Weinzierl U. , Schmidt S. , Becker H. , Kalt H. , Mappes T. , Koeber S. , Koos C.
Published: August 2015

We present an all-polymer photonic sensing platform based on whispering-gallery mode microgoblet lasers integrated into a microfluidic chip.
The gene expression profiling of hepatocellular carcinoma by a network analysis approach shows a dominance of intrinsically disordered proteins (IDPs) between hub nodes
Authors: Singh Sakshi , Colonna Giovanni , Di Bernardo Giovanni , Bergantino Francesca , Cammarota Marcella , Castello Giuseppe , Costantini Susan
Published: August 2015

The results evidence a strong presence of intrinsically disordered proteins in key roles as hubs in HCC sub-networks.
Systems biology-based discovery of a potential Atg4B agonist (Flubendazole) that induces autophagy in breast cancer
Authors: Zhang Lan , Guo Mingrui , Li Jing , Zheng Yaxin , Zhang Shouyue , Xie Tao , Liu Bo
Published: August 2015

The aim of this study was to explore the autophagy-related protein 4B(ATG4B) and its targeted candidate agonist in triple-negative breast cancer (TNBC) therapy.
A novel protocol for the facile construction of tetrahydroquinoline fused tricyclic frameworks via an intramolecular 1,3-dipolar nitrile oxide cycloaddition reaction
Authors: Bakthadoss Manickam , Vinayagam Varathan
Published: August 2015

An efficient method towards the synthesis of quinoline fused tricyclic compounds involving an intramolecular 1,3-dipolar nitrile oxide cycloaddition reaction utilizing Baylis–Hillman derivatives in good yields has been described for the first time.
A mesoporous SBA-15 silica catalyst functionalized with phenylsulfonic acid groups (SBA-15-Ph-SO3H) as a novel hydrophobic nanoreactor solid acid catalyst for a one-pot three-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones and triazolo[1,2-a]indazole-triones
Authors: Veisi Hojat , Sedrpoushan Alireza , Faraji Ali Reza , Heydari Masoud , Hemmati Saba , Fatahi Behnaz
Published: August 2015

Phenyl sulfonic acid functionalized mesoporous SBA-15 silica was prepared through the silanization of activated mesoporous SBA-15 with diphenyldichlorosilane followed by silylation and sulfonation.
Enhancement by the artificial controlled culture for the algal treatment of antibiotic ceftazidime: a three-step response performance and high-removal efficiency
Authors: Du Yingxiang , Feng Yunqing , Guo Ruixin , Chen Jianqiu
Published: August 2015

The improved activity of alga is critical for the biological enhanced treatment to remove contamination.
Optimization of the microalgae Chlorella vulgaris for syngas production using central composite design
Authors: Raheem Abdul , W. A. K. G. Wan Azlina , Taufiq Yap Y. H. , Danquah Michael K. , Harun Razif
Published: August 2015

Microalgal gasification for syngas production using a high temperature horizontal tubular furnace was optimized under varying conditions of temperature, microalgal biomass loading, heating rate and equivalent ratio.
Deoxygenation of graphene oxide using household baking soda as a reducing agent: a green approach
Authors: Aunkor M. T. H. , Mahbubul I. M. , Saidur R. , Metselaar H. S. C.
Published: August 2015

A one-step, novel, easy, fast, facile, economic, and environmental friendly route to reduce graphene oxide (GO) is studied and explained in this study.
Band gap engineering of graphenylene by hydrogenation and halogenation: a density functional theory study
Authors: Liu Wei , Miao Mao-sheng , Liu Jing-yao
Published: August 2015

Density functional theory study shows that by controlling the concentration of adsorbate atoms, the band gap of graphenylene could be tuned in a wide range, from 0.075 to 4.98 eV by hydrogenation and 0.024 eV to 4.87 eV by halogenation.
BaGeO3 as sintering additive for BaTiO3–MgFe2O4 composite ceramics
Authors: Köferstein R. , Ebbinghaus S. G.
Published: August 2015

Multiferroic composites of BaTiO3–MgFe2O4 were prepared with a small addition of BaGeO3. BaGeO3 as sintering additive influences the dielectric behaviour, leading to increasing permittivity values and decreasing dissipation factors.
Microphase separated sepiolite-based nanocomposite blends of fully sulfonated poly(ether ketone)/non-sulfonated poly(ether sulfone) as proton exchange membranes from dual electrospun mats
Authors: Oroujzadeh Maryam , Mehdipour-Ataei Shahram , Esfandeh Masoud
Published: August 2015

In this study, nanocomposite blends of fully sulfonated poly(ether ketone) (PEK) and non-sulfonated poly(ether sulfone) (PES) were prepared from a dual electrospinning process.
Modeling of a natural lipstick formulation using an artificial neural network
Authors: Kamairudin Norsuhaili , Abd Gani Siti Salwa , Fard Masoumi Hamid Reza , Basri Mahiran , Hashim Puziah , Mokhtar Norfadzillah Mohd , Lane Majella E.
Published: August 2015

An artificial neural network (ANN) was applied in conjunction with experimental data from a mixture of experimental designs to predict the melting point of a lipstick formulation.
Preparation of molecularly imprinted polymers based on magnetic carbon nanotubes for determination of sulfamethoxazole in food samples
Authors: Zhao Yingran , Bi Changfen , He Xiwen , Chen Langxing , Zhang Yukui
Published: August 2015

An efficient approach was developed to synthesize the imprinted magnetic carbon nanotubes nanocomposite and apply for sulfamethoxazole enrichment from milk and honey samples.
Enhanced antibacterial activity of Cr doped ZnO nanorods synthesized using microwave processing
Authors: Vijayalakshmi K. , Sivaraj D.
Published: August 2015

Light induced generation of reactive oxygen species from ZnO and Cr:ZnO nanoparticles.
An efficient three-component synthesis of coumarin-3-carbamides by use of Ni–NiO nanoparticles as magnetically separable catalyst
Authors: Sepay Nayim , Guha Chayan , Kool Arpan , Mallik Asok K.
Published: August 2015

An efficient and ecofriendly synthesis of coumarin-3-carbamides has been developed by a three-component reaction of 2-hydroxybenzaldehydes, aliphatic amines (p-/s-) and diethyl malonate using Ni–NiO nanoparticles as catalyst.
Novel aromatic polyimides derived from 2,8-di(3-aminophenyl)dibenzofuran. Synthesis, characterization and evaluation of properties
Authors: Tundidor-Camba Alain , Terraza Claudio A. , Tagle Luis H. , Coll Deysma , Ortiz Pablo , de Abajo Javier , Maya Eva M.
Published: August 2015

Three aromatic polyimides (PIs) were prepared from a new aromatic diamine monomer derived from the rigid ring dibenzofuran.
Quinoxaline: a new directing group for ortho C–H alkenylation / intramolecular ortho C–H cycloamination under open air leading to bioactive polynuclear N-heteroarenes
Authors: Sunke Rajnikanth , Kumar Vimal , Venkat Shivaji Ramarao E. V. , Bankala Ramudu , Parsa Kishore V. L. , Pal Manojit
Published: August 2015

A two-step strategy involving quinoxaline directed theorthoC–H alkenylation/intramolecularorthoC–H cycloamination afforded new PDE4 inhibitors.
Naphtho[1,2b;5,6b′]difuran-based donor–acceptor polymers for high performance organic field-effect transistors
Authors: Shi Shaowei , Shi Keli , Yu Gui , Li Xiaoyu , Wang Haiqiao
Published: August 2015

Two naphthodifuran-based donor–acceptor copolymers are presented. Via reasonable main-chain modification and side-chain engineering, remarkably dense π–π stacking spacings (2 V−1 s−1 are achieved at a moderate annealing temperature of 120 °C.
Blue-silica by Eu2+-activator occupied in interstitial sites
Authors: Kim Donghyeon , Jin Yoeng-Hun , Jeon Ki-Wan , Kim Sungyun , Kim Seung-Joo , Han Oc Hee , Seo Dong-Kyun , Park Jung-Chul
Published: August 2015

A blue-emitting SiO2:Eu2+ compound has been successfully synthesized and characterized.
Switching wormlike micelles of selenium-containing surfactant using redox reaction
Authors: Zhang Yongmin , Kong Weiwei , Wang Cheng , An Pengyun , Fang Yun , Feng Yujun , Qin Zhirong , Liu Xuefeng
Published: August 2015

Wormlike micelles based on a selenium-containing surfactant and a commercially anionic surfactant reversibly respond to H2O2 and vitamin C, and show circulatory gel/sol transition, reflecting changes in aggregate morphology from entangled worms to vesicles.
Interfacial lattice-strain effects on improving the overall performance of micro-solid oxide fuel cells
Authors: Wen Kechun , Lv Weiqiang , He Weidong
Published: August 2015

This review overviews interfacial-strain effects on ion transport, oxygen vacancy formation, and oxygen adsorption in micro-solid oxide fuel cells.
A crystalline Cu–Sn–S framework for high-performance lithium storage
Authors: Nie Lina , Zhang Yu , Ye Kaiqi , Han Jianyu , Wang Yue , Rakesh Ganguly , Li Yongxin , Xu Rong , Yan Qingyu , Zhang Qichun
Published: August 2015

The three-dimensional crystalline (H3O)2(enH2)Cu8Sn3S12framework exhibits a high capacity of 563 mA h g−1at a current density of 0.1 A g−1with high stability.
Hole-conductor-free planar perovskite solar cells with 16.0% efficiency
Authors: Li Yunlong , Ye Senyun , Sun Weihai , Yan Weibo , Li Yu , Bian Zuqiang , Liu Zhiwei , Wang Shufeng , Huang Chunhui
Published: August 2015

In the present work, a hole-conductor-free inverted-structure planar perovskite solar cell was fabricated by a solution process.
PEG modified graphene oxide loaded with EALYLV peptides for inhibiting the aggregation of hIAPP associated with type-2 diabetes
Authors: Zhou Xianbo , Cao Chengwen , Chen Qingchang , Yu Qianqian , Liu Yanan , Yin Tiantian , Liu Jie
Published: August 2015

Human islet amyloid polypeptide (hIAPP) was found as amyloid aggregate deposits in the pancreatic islets of patients with type-2 diabetes and studies showed that insulin and its derivatives were the potent inhibitors of hIAPP aggregation.
Sugar based nanotube assembly for the construction of sonication triggered hydrogel: an application of the entrapment of tetracycline hydrochloride
Authors: Ma Zichuan , Zhang Ping , Yu Xudong , Lan Haichuang , Li Yajuan , Xie Dongyan , Li Jingyin , Yi Tao
Published: August 2015

The tube assembly comprised of naphthalimide and glucose segments could undergo direct suspension-to-hydrogel transformation accelerated by ultrasound.
Liposomal nanohybrid cerasomes for mitochondria-targeted drug delivery
Authors: Wang Yanfang , Wang Beibei , Liao Han , Song Xiaojie , Wu Hao , Wang Huihui , Shen Hujun , Ma Xiaojun , Tan Mingqian
Published: August 2015

A general and facile synthesis method was reported to fabricate TPP modified liposomal cerasomes as nanocarriers for mitochondria-targeted drug delivery.
A facilely controlled length, cytotoxicity, length-dependent and cell type-dependent cellular uptake of silica nanotubes and their applications in the delivery of immunostimulatory CpG oligodeoxynucleotides
Authors: Chen Song , Zhang Qiqing , Jia Lan , Du Xinxin , Hanagata Nobutaka
Published: August 2015

Silica nanotubes were synthesized via an acid-degradation collagen template route and then functionalized with chitosan to deliver immunostimulatory CpG-ODN.
Delivery of AIB1 siRNA by Ca2+/PEI/heparin composite nanoparticles effectively inhibits the growth of human breast cancer
Authors: Cheang T. Y. , Xing Z. H. , Li Z. L. , Zhou H. Y. , Wei J. H. , Zhou X. , Xu A. W. , Lin Y. , Wang S. M.
Published: August 2015

Here, a novel carrier fabricated by the interaction of negatively charged heparin and positively charged PEI and Ca2+ was investigated to deliver AIB1 siRNA to breast cancer cells both in vitro and in vivo.
Tunable 500 GHz sensor system in SiGe technology for gas spectroscopy
Authors: Schmalz K. , Borngräber J. , Debski W. , Neumaier P. , Wang R. , Kissinger D. , Hübers H.‐W.
Published: August 2015

A 500 GHz system for gas spectroscopy is presented, which includes an SiGe 4 × 1 transmitter (TX)‐array, an SiGe subharmonic receiver (RX) and a 1.9 m‐long gas absorption cell. The 120 GHz local oscillators (LOs) of the TX‐array and RX are controlled by two external phase‐locked loops (PLLs), whose reference frequencies are swept. The TX involves a frequency quadrupler. The RX uses a frequency doubler for the 120 GHz LO frequency, which is connected to a subharmonic transconductance mixer. The absorption spectrum of a gaseous mixture of methanol and acetonitrile is measured from 495 to 497 GHz.
Circularly polarised MIMO tapered slot antenna array for C‐band application
Authors: Karamzadeh S. , Kartal M.
Published: August 2015

A novel configuration of a multiple‐input multiple‐output (MIMO) circularly polarised (CP) antenna array operating in the C‐band is presented. The array consists of 2 × 2 antipodal tapered slot antenna elements created in the sides of a rectangular as the rectangular grid that supplies a broadband impedance bandwidth and high gain array. To provide broadband MIMO with polarisation diversity, the antenna uses a dual‐port feed network consisting of couplers, a crossover and delay lines which the diversity of polarisation changed by input ports.
Investigation of traps in strained‐well InGaAs/GaAsSb quantum well photodiodes
Authors: Chen W. , Chen B. , Holmes A. , Fay P.
Published: August 2015

InP‐based strained‐well InGaAs/GaAsSb quantum well photodiodes with non‐zero net strain can be used to extend detection wavelengths well into the mid‐infrared region. However, excess dark current due to defects in the structure can be a performance limiting factor in photodiodes of this type. In this reported work, both low‐frequency noise spectroscopy and deep level transient spectroscopy were used to investigate traps in prototypical strained‐well photodiode heterostructures. Two distinct traps were identified and their electrical and physical properties and distributions have been evaluated.
Proposal of geographic information systems methodology for quality control procedures of data obtained in naturalistic driving studies
Authors: Balsa‐Barreiro José , Valero‐Mora Pedro M. , Pareja‐Montoro Ignacio , Sánchez‐García Mar
Published: August 2015

The primary goal of naturalistic driving studies is to provide a comprehensive observation of the driver's behaviour under real‐life conditions by measureing a great number of parameters at high temporal frequencies. Achieving this goal, however, is a complex endeavor that faces many challenges such as the complexity of the vehicle instrumentation during the phase of data collection, and the difficult handling of large data volumes during the phase of data analysis. These drawbacks often cause episodes of data losses. Improving the technical aspects of the collection of naturalistic data is of paramount importance to increase the return of the investment made in it. An aspect to consider is the control of the quality of data obtained. The procedures commonly applied often present a high workload and low levels of reliability in the results. For this reason, new and more efficient procedures should be implemented. This study proposes an innovative methodology for the quality control of these data through geographic information systems (GIS), which permit a fast, efficient and effective data evaluation. Relative and absolute errors can be located through cartographic representation obtained with GIS. Some graphical examples about the detection of the errors are shown.
Simulation and design of a tuneable ferrite resonator antenna based on nanostructured nickel ferrite material
Authors: Silva Neto V.P. , Vasconcelos C.F.L. , Bomio M.R.D. , Albuquerque M.R.M.L. , Araújo J.H. , D'Assunção A.G.
Published: August 2015

A tuneable ferrite resonator antenna (FRA) based on nanostructured nickel ferrite (NiFe2O4) material is proposed. Magnetic and dielectric characteristics are determined for the NiFe2O4 material such as electrical permittivity, and hysteresis loops. This ferrite material is used as a microwave resonator in the designing and fabrication of a cylindrical FRA. Ansoft high‐frequency structure simulator software is used to provide simulated results for the antenna parameters such as resonant frequency, return loss, input impedance, and radiation pattern. A resonant frequency tuning capability with the application of a varied external magnetic bias field is shown. Measurement of the antenna prototype is also carried out and the obtained results are in good agreement with the simulated ones.
Optimal design of focused arrays for microwave‐induced hyperthermia
Authors: He Xiaoping , Geyi Wen , Wang Shenyun
Published: August 2015

This study studies optimal design of focused antenna arrays for microwave‐induced hyperthermia. The phases and amplitudes of the driving signals of array elements are determined by optimising the power transmission efficiency of the system consisting of the transmitting antenna array, a receiving antenna located in the target area, and an equivalent phantom representative of human tissues. On the basis of the proposed technique, a 4 × 2 focused patch array is designed to operate on a fat‐mimicking phantom with working frequency at 433 MHz. The measured patterns for specific absorption rate indicate that the energy is focused in the desired spot and are in close agreement with simulations, which validate the optimisation method in a medium with low permittivity and low loss. A 4 × 3 focused patch array operating on a human body phantom with same working frequency is then designed, in which an air space and two additional dielectric layers have been introduced between the planar array and the body‐mimicking phantom for impedance matching. A good focal performance at desired spot is also achieved, and the simulated and measured specific absorption rate patterns agree very well. This demonstrates the validity of the proposed design method in a medium with high permittivity and high loss.
Broadband microstrip antenna using epsilon near zero metamaterials
Authors: Jafargholi Amir , Mazaheri Mohammad Hossein
Published: August 2015

In this study, the effect of loading microstrip antenna using epsilon near zero (ENZ) metamaterial is investigated. It is known that ENZ material may help to improve the transmission through a boundary condition and that the scattering parameters may be completely independent of such boundary properties. This idea is demonstrated to significantly increase the bandwidth of a simple rectangular microstrip patch antenna. To realise the ENZ material, a periodic wire medium is designed, simulated, fabricated, and tested. Simulation results based on CST Microwave studio have good agreement with measurements.
Logarithmic derivative method and system for capacitance measurement
Authors: Wu Yichun , Wang Lingzhi , Cai Yuanfeng , Wu Cunqiao
Published: August 2015

A novel method based on logarithmic derivative is introduced to analyze multi-lifetime decay. As the discharge voltage signal of a RC circuit is a special kind of multi-lifetime exponential decay, the logarithmic derivative method can be used to measure single capacitance and multiple capacitances. With the logarithmic derivative method, a log(t) curve strongly peaked at precisely log(τ) is obtained, where the lifetime τ equals to RC. In a measurement system, if the resistance R is known, then the capacitance under test can be calculated. A logarithmic derivative curve fitting method is also presented, which has better anti-noise capability than the method that simply finds the maximum data on the peak. The curve fitting method can also be used for multiple capacitors measurement. To measure small capacitances, a large enough time window of the measuring instrument is required. Based on a field programmable gate array and a high speed analog-to-digital converter, a measurement system is developed. This system can provide the 16-bit resolution with sampling rate up to 250 MHz, which has a large enough time window for measuring lifetime shorter than 10−8 s. To reduce the amount of data needed to be stored and the noise due to the derivative treatment of transient data, the interpolation and noise-filter algorithms are employed. Experiments indicate that the logarithmic derivative method and system are suitable for the measurement of capacitances discharge and other exponential decay processes.
Chemical bonding in hydrogen and lithium under pressure
Authors: Naumov Ivan I. , Hemley Russell J. , Hoffmann Roald , Ashcroft N. W.
Published: August 2015

Though hydrogen and lithium have been assigned a common column of the periodic table, their crystalline states under common conditions are drastically different: the former at temperatures where it is crystalline is a molecular insulator, whereas the latter is a metal that takes on simple structures. On compression, however, the two come to share some structural and other similarities associated with the insulator-to-metal and metal-to-insulator transitions, respectively. To gain a deeper understanding of differences and parallels in the behaviors of compressed hydrogen and lithium, we performed an ab initio comparative study of these systems in selected identical structures. Both elements undergo a continuous pressure-induced s-p electronic transition, though this is at a much earlier stage of development for H. The valence charge density accumulates in interstitial regions in Li but not in H in structures examined over the same range of compression. Moreover, the valence charge density distributions or electron localization functions for the same arrangement of atoms mirror each other as one proceeds from one element to the other. Application of the virial theorem shows that the kinetic and potential energies jump across the first-order phase transitions in H and Li are opposite in sign because of non-local effects in the Li pseudopotential. Finally, the common tendency of compressed H and Li to adopt three-fold coordinated structures as found is explained by the fact that such structures are capable of yielding a profound pseudogap in the electronic densities of states at the Fermi level, thereby reducing the kinetic energy. These results have implications for the phase diagrams of these elements and also for the search for new structures with novel properties.
Charged patchy particle models in explicit salt: Ion distributions, electrostatic potentials, and effective interactions
Authors: Yigit Cemil , Heyda Jan , Dzubiella Joachim
Published: August 2015

We introduce a set of charged patchy particle models (CPPMs) in order to systematically study the influence of electrostatic charge patchiness and multipolarity on macromolecular interactions by means of implicit-solvent, explicit-ion Langevin dynamics simulations employing the Gromacs software. We consider well-defined zero-, one-, and two-patched spherical globules each of the same net charge and (nanometer) size which are composed of discrete atoms. The studied mono- and multipole moments of the CPPMs are comparable to those of globular proteins with similar size. We first characterize ion distributions and electrostatic potentials around a single CPPM. Although angle-resolved radial distribution functions reveal the expected local accumulation and depletion of counter- and co-ions around the patches, respectively, the orientation-averaged electrostatic potential shows only a small variation among the various CPPMs due to space charge cancellations. Furthermore, we study the orientation-averaged potential of mean force (PMF), the number of accumulated ions on the patches, as well as the CPPM orientations along the center-to-center distance of a pair of CPPMs. We compare the PMFs to the classical Derjaguin-Verwey-Landau-Overbeek theory and previously introduced orientation-averaged Debye-Hückel pair potentials including dipolar interactions. Our simulations confirm the adequacy of the theories in their respective regimes of validity, while low salt concentrations and large multipolar interactions remain a challenge for tractable theoretical descriptions.
A novel apparatus for in situ measurement of thermal conductivity of hydrate-bearing sediments
Authors: Zhao Jiafei , Wang Bin , Yang Lei , Cheng Chuanxiao , Song Yongchen
Published: August 2015

An experimental apparatus was developed to synthesize natural gas hydrates and measure the thermal conductivity of hydrate-bearing sediments in situ. The apparatus works over a temperature range varying from −20 °C to 50 °C and up to a maximum pressure of 20 MPa. This apparatus is mainly composed of a thermal conductivity test system and a reaction cell, into which a lab-fabricated thermistor probe is inserted. This thermistor has excellent temperature sensitivity and can work at high pressures. The basic principles of this apparatus are discussed, and a series of experiments were performed to verify that the apparatus can be practically applied in chemical engineering. The thermistor-based measuring method was applied successfully in a high-pressure environment both with and without porous media.
Precision measurement of refractive index of air based on laser synthetic wavelength interferometry with Edlén equation estimation
Authors: Yan Liping , Chen Benyong , Zhang Enzheng , Zhang Shihua , Yang Ye
Published: August 2015

A novel method for the precision measurement of refractive index of air (nair) based on the combining of the laser synthetic wavelength interferometry with the Edlén equation estimation is proposed. First, a nair_e is calculated from the modified Edlén equation according to environmental parameters measured by low precision sensors with an uncertainty of 10−6. Second, a unique integral fringe number N corresponding to nair is determined based on the calculated nair_e. Then, a fractional fringe ε corresponding to nair with high accuracy can be obtained according to the principle of fringe subdivision of laser synthetic wavelength interferometry. Finally, high accurate measurement of nair is achieved according to the determined fringes N and ε. The merit of the proposed method is that it not only solves the problem of the measurement accuracy of nair being limited by the accuracies of environmental sensors, but also avoids adopting complicated vacuum pumping to measure the integral fringe N in the method of conventional laser interferometry. To verify the feasibility of the proposed method, comparison experiments with Edlén equations in short time and in long time were performed. Experimental results show that the measurement accuracy of nair is better than 2.5 × 10−8 in short time tests and 6.2 × 10−8 in long time tests.
Mean field theory for biology inspired duplication-divergence network model
Authors: Cai Shuiming , Liu Zengrong , Lee H. C.
Published: August 2015

The duplication-divergence network model is generally thought to incorporate key ingredients underlying the growth and evolution of protein-protein interaction networks. Properties of the model have been elucidated through numerous simulation studies. However, a comprehensive theoretical study of the model is lacking. Here, we derived analytic expressions for quantities describing key characteristics of the network—the average degree, the degree distribution, the clustering coefficient, and the neighbor connectivity—in the mean-field, large-N limit of an extended version of the model, duplication-divergence complemented with heterodimerization and addition. We carried out extensive simulations and verified excellent agreement between simulation and theory except for one partial case. All four quantities obeyed power-laws even at moderate network size (N∼104), except the degree distribution, which had an additional exponential factor observed to obey power-law. It is shown that our network model can lead to the emergence of scale-free property and hierarchical modularity simultaneously, reproducing the important topological properties of real protein-protein interaction networks.
Research Update: Towards designed functionalities in oxide-based electronic materials
Authors: Rondinelli James M. , Poeppelmeier Kenneth R. , Zunger Alex
Published: August 2015

One of the grand challenges facing materials-by-design approaches for complex oxide deployment in electronic devices is how to balance transformative first-principles based predictions with experimental feasibility. Here, we briefly review the functionality-driven approach (inverse design) for materials discovery, encapsulated in three modalities for materials discovery (m3D) that integrate experimental feedback. We compare it to both traditional theoretical and high-throughput database-directed approaches aimed at advancing oxide-based materials into technologies.
Superconducting magnetoresistance effect observed in Co/Nb/Co trilayers under a parallel magnetic field: The importance of matching the width of magnetic domain walls of the Co layers with the thickness of the Nb interlayer
Authors: Aristomenopoulou E. , Stamopoulos D.
Published: August 2015

Magnetoresistance effects observed in ferromagnet/superconductor (FM/SC) hybrids, FM/SC bilayers (BLs) and FM/SC/FM trilayers (TLs), have attracted much interest. Here, we focus on the stray-fields-based superconducting magnetoresistance effect (sMRE) observed in Co(dCo)/Nb(dNb)/Co(dCo) TLs with sufficiently thick Co outer layers so that out-of-plane magnetic domains (MDs) and MDs walls (MDWs) emerge all over their surface when subjected to a parallel external magnetic field, Hex, equal to the coercive field, Hc. To explore the conditions necessary for maximization of the sMRE, we focus on the different kinds of the stray dipolar fields, Hdip, that emerge at the interior of the out-of-plane MDs and at the boundaries of MDWs; these have a different inherent tendency to create straight and semi-loop vortices, respectively. In the recent literature, the creation of straight and semi-loop vortices has been addressed at some extent both theoretically [Laiho et al., Phys. Rev. B 67, 144522 (2003)] and experimentally [Bobba et al., Phys. Rev. B 89, 214502 (2014)] for the case of FM/SC BLs. Here, we address these issues in FM/SC/FM TLs in connection to the sMRE. Specifically, we focus on an experimental finding reported recently [D. Stamopoulos and E. Aristomenopoulou, J. Appl. Phys. 116, 233908 (2014)]; strong magnetostatic coupling of the FM outer layers is accompanied by an intense sMRE in TLs in which the thickness of the SC interlayer, dSC, matches the width of MDWs, DMDWs. To investigate this finding, we employ simulations-modeling and energy-considerations and propose two quantitative criteria that facilitate the creation of straight vortices over semi-loop ones. The first focuses on the maximization of the stray Hdip that occur at the interior of the out-of-plane MDs. The second enables the estimation of a crossover between the preferable creation of one kind of vortices over the other. Both criteria respond well, when tested against experimental results. These generic criteria on the interference between dSC and DMDWs can assist the design of cryogenic devices based on FM/SC/FM TLs.
Synchronizability of random rectangular graphs
Authors: Estrada Ernesto , Chen Guanrong
Published: August 2015

Random rectangular graphs (RRGs) represent a generalization of the random geometric graphs in which the nodes are embedded into hyperrectangles instead of on hypercubes. The synchronizability of RRG model is studied. Both upper and lower bounds of the eigenratio of the network Laplacian matrix are determined analytically. It is proven that as the rectangular network is more elongated, the network becomes harder to synchronize. The synchronization processing behavior of a RRG network of chaotic Lorenz system nodes is numerically investigated, showing complete consistence with the theoretical results.
The geometrical change and intramolecular energy transfer upon S1←S excitation in cyclopentanone
Authors: Wang Yanmei , Liu Zhiming , Xu Yanqi , Zhang Bing
Published: August 2015

The ultrafast dynamics in vibrationally hot S1 electronic excited state in cyclopentanone molecule was discovered with time resolved spectroscopy. Investigation of the geometry change upon the S1←S0 excitation and D0←S1 ionization has shown that the dihedral angle between the C=O bond and the plane given by the carbonyl and the α-carbons is 180° either in S0 or D0 state and is reduced to 145.8° by out-out-plane deformation of the oxygen in S1 state according to the theoretical calculation. The time domain experiments with femtosecond resolution have given rich insights into the energy transfer of the cyclopentanone molecule. The molecules are excited to the vibrationally hot S1 (n,  π∗) state following absorption of one 267-nm photon. It is found that the population of the S1 (n, π∗) state undergoes ultrafast internal conversion to the highly vibrationally hot S0 state within 80 fs and nonradiative deactivation by intersystem crossing to triplet T1 (n, π*) state occurring in 3.14 ps. Several Rydberg states have worked as stepping stones during the ionization. The available energy was distributed in the symmetric methylene group wagging and the symmetric skeletal ring breathing modes in D0 state.
Highly reflective polymeric substrates functionalized utilizing atomic layer deposition
Authors: Zuzuarregui Ana , Coto Borja , Rodríguez Jorge , Gregorczyk Keith E. , Ruiz de Gopegui Unai , Barriga Javier , Knez Mato
Published: August 2015

Reflective surfaces are one of the key elements of solar plants to concentrate energy in the receivers of solar thermal electricity plants. Polymeric substrates are being considered as an alternative to the widely used glass mirrors due to their intrinsic and processing advantages, but optimizing both the reflectance and the physical stability of polymeric mirrors still poses technological difficulties. In this work, polymeric surfaces have been functionalized with ceramic thin-films by atomic layer deposition. The characterization and optimization of the parameters involved in the process resulted in surfaces with a reflection index of 97%, turning polymers into a real alternative to glass substrates. The solution we present here can be easily applied in further technological areas where seemingly incompatible combinations of polymeric substrates and ceramic coatings occur.
Spin-glass behaviors in carrier polarity controlled Fe3−xTixO4 semiconductor thin films
Authors: Yamahara H. , Seki M. , Adachi M. , Takahashi M. , Nasu H. , Horiba K. , Kumigashira H. , Tabata H.
Published: August 2015

Carrier-type control of spin-glass (cluster spin-glass) is studied in order to engineer basic magnetic semiconductor elements using the memory functions of spin-glass. A key of carrier-polarity control in magnetite is the valence engineering between Fe(II) and Fe(III) that is achieved by Ti(IV) substitution. Single phases of (001)-oriented Fe3−xTixO4 thin films have been obtained on spinel MgAl2O4 substrates by pulsed laser deposition. Thermoelectric power measurements reveal that Ti-rich films (x = 0.8) show p-type conduction, while Ti-poor films (x = 0.6–0.75) show n-type conduction. The systematic Fe(III) reduction to Fe(II) followed by Ti(IV) substitution in the octahedral sublattice is confirmed by the X-ray absorption spectra. All of the Fe3−xTixO4 films (x = 0.6–0.8) exhibit ferrimagnetism above room temperature. Next, the spin-glass behaviors of Ti-rich Fe2.2Ti0.8O4 film are studied, since this magnetically diluted system is expected to exhibit the spin-glass behaviors. The DC magnetization and AC susceptibility measurements for the Ti-rich Fe2.2Ti0.8O4 film reveal the presence of the spin glass phase. Thermal- and magnetic-field-history memory effects are observed and are attributed to the long time-decay nature of remanent magnetization. The detailed analysis of the time-dependent thermoremanent magnetization reveals the presence of the cluster spin glass state.