bluuebunny/crossref_metadata_2025 huggingface dataset:
A cohesive law for interfaces in graphene/hexagonal boron nitride heterostructure
Authors: Zhang Chenxi , Lou Jun , Song Jizhou
Published: April 2014

Graphene/hexagonal boron nitride (h-BN) heterostructure has showed great potential to improve the performance of graphene device. We have established the cohesive law for interfaces between graphene and monolayer or multi-layer h-BN based on the van der Waals force. The cohesive energy and cohesive strength are given in terms of area density of atoms on corresponding layers, number of layers, and parameters in the van der Waals force. It is found that the cohesive law in the graphene/multi-layer h-BN is dominated by the three h-BN layers which are closest to the graphene. The approximate solution is also obtained to simplify the expression of cohesive law. These results are very useful to study the deformation of graphene/h-BN heterostructure, which may have significant impacts on the performance and reliability of the graphene devices especially in the areas of emerging applications such as stretchable electronics.
t matrix of metallic wire structures
Authors: Zhan T. R. , Chui S. T.
Published: April 2014

To study the electromagnetic resonance and scattering properties of complex structures of which metallic wire structures are constituents within multiple scattering theory, the t matrix of individual structures is needed. We have recently developed a rigorous and numerically efficient equivalent circuit theory in which retardation effects are taken into account for metallic wire structures. Here, we show how the t matrix can be calculated analytically within this theory. We illustrate our method with the example of split ring resonators. The density of states and cross sections for scattering and absorption are calculated, which are shown to be remarkably enhanced at resonant frequencies. The t matrix serves as the basic building block to evaluate the interaction of wire structures within the framework of multiple scattering theory. This will open the door to efficient design and optimization of assembly of wire structures.
Note: Neutron bang time diagnostic system on Shenguang-III prototype
Authors: Tang Qi , Chen Jiabin , Liu Zhongjie , Zhan Xiayu , Song Zifeng
Published: April 2014

A neutron bang time (NBT) diagnostic system has been implemented on Shenguang-III prototype. The bang time diagnostic system is based on a sensitive fusion neutron detector, which consists of a plastic scintillator and a micro-channel plate photomultiplier tube (PMT). An optical fiber bundle is used to couple the scintillator and the PMT. The bang time system is able to measure bang time above a neutron yield of 107. Bang times and start time of laser were related by probing x-ray pulses produced by 200 ps laser irradiating golden targets. Timing accuracy of the NBT is better than 60 ps.
Inter-band optoelectronic properties in quantum dot structure of low band gap III-V semiconductors
Authors: Dey Anup , Maiti Biswajit , Chanda (Sarkar) Debasree
Published: April 2014

A generalized theory is developed to study inter-band optical absorption coefficient (IOAC) and material gain (MG) in quantum dot structures of narrow gap III-V compound semiconductor considering the wave-vector (k→) dependence of the optical transition matrix element. The band structures of these low band gap semiconducting materials with sufficiently separated split-off valance band are frequently described by the three energy band model of Kane. This has been adopted for analysis of the IOAC and MG taking InAs, InSb, Hg1−xCdxTe, and In1−xGaxAsyP1−y lattice matched to InP, as example of III–V compound semiconductors, having varied split-off energy band compared to their bulk band gap energy. It has been found that magnitude of the IOAC for quantum dots increases with increasing incident photon energy and the lines of absorption are more closely spaced in the three band model of Kane than those with parabolic energy band approximations reflecting the direct the influence of energy band parameters. The results show a significant deviation to the MG spectrum of narrow-gap materials having band nonparabolicity compared to the parabolic band model approximations. The results reflect the important role of valence band split-off energies in these narrow gap semiconductors.
Ballistic vs. diffusive heat transfer across nanoscopic films of layered crystals
Authors: Shen Meng , Keblinski Pawel
Published: April 2014

We use non-equilibrium molecular dynamics to study the heat transfer mechanism across sandwich interfacial structures of Si/n-atomic-layers/Si, with 1 ≤ n ≤ 20 and atomic layers composed of WSe2 and/or graphene. In the case of WSe2 sheets, we observe that the thermal resistance of the sandwich structure is increasing almost linearly with the number of WSe2 sheets, n, indicating a diffusive phonon transport mechanism. By contrast in the case of n graphene layers, the interfacial thermal resistance is more or less independent on the number of layers for 1 ≤ n ≤ 10, and is associated with ballistic phonon transport mechanism. We attribute the diffusive heat transfer mechanism across WSe2 sheets to abundant low frequency and low group velocity optical modes that carry most of the heat across the interface. By contrast, in graphene, acoustic modes dominate the thermal transport across the interface and render a ballistic heat flow mechanism.
Strain-mediated voltage control of magnetism in multiferroic Ni77Fe23/Pb(Mg1/3Nb2/3)0.7Ti0.3O3 heterostructure
Authors: Gao Ya , Hu Jiamian , Shu Li , Nan C. W.
Published: April 2014

Using voltage-modified anisotropic magnetoresistance (AMR) measurement, we demonstrated a strain-mediated voltage control of magnetism in multiferroic Ni77Fe23(NiFe, 10 nm)/Pb (Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT, bulk crystal) heterostructure, even assuming a very small magnetostriction (∼0.3 ppm) for the NiFe film which has a composition close to bulk permalloy (Ni80Fe20). Influence of the magnitude of the rotating magnetic field used for AMR tests is studied. Combined AMR and theoretical analysis indicate the voltage-modified change in the magnetoresistance of the NiFe film arises from the reduced free energy barrier between the magnetic easy axis and hard axis via voltage-induced strains in the PMN-PT.
Excitation mechanism and thermal emission quenching of Tb ions in silicon rich silicon oxide thin films grown by plasma-enhanced chemical vapour deposition—Do we need silicon nanoclusters?
Authors: Podhorodecki A. , Golacki L. W. , Zatryb G. , Misiewicz J. , Wang J. , Jadwisienczak W. , Fedus K. , Wojcik J. , Wilson P. R. J. , Mascher P.
Published: April 2014

In this work, we will discuss the excitation and emission properties of Tb ions in a Silicon Rich Silicon Oxide (SRSO) matrix obtained at different technological conditions. By means of electron cyclotron resonance plasma-enhanced chemical vapour deposition, undoped and doped SRSO films have been obtained with different Si content (33, 35, 39, 50 at. %) and were annealed at different temperatures (600, 900, 1100 °C). The samples were characterized optically and structurally using photoluminescence (PL), PL excitation, time resolved PL, absorption, cathodoluminescence, temperature dependent PL, Rutherford backscattering spectrometry, Fourier transform infrared spectroscopy and positron annihilation lifetime spectroscopy. Based on the obtained results, we discuss how the matrix modifications influence excitation and emission properties of Tb ions.
A field shaping printhead for high-resolution electrohydrodynamic jet printing onto non-conductive and uneven surfaces
Authors: Tse Leo , Barton Kira
Published: April 2014

High-resolution electrohydrodynamic jet printing is a cost effective, flexible, multi-material, high-resolution (sub 10 μm) additive manufacturing process. In this paper, we present an electric field shaping printhead capable of controlled high-resolution (sub 10 μm) e-jet printing and demonstrate printhead capabilities by creating patterns with both an optical adhesive and silver nanoparticle ink material with equivalent accuracy to state-of-the-art e-jet printing. Importantly, we demonstrate controlled printing onto non-conductive and height varying surfaces without the use of a grounded substrate at a previously unattainable length scale. This ability to print onto highly varied non-conductive substrates will enable the generalization of the 2D process to a controlled 3D printing technology at the micro-scale.
Synergistic effect of V/N codoping by ion implantation on the electronic and optical properties of TiO2
Authors: Xu Jinxia , Chen Chi , Xiao Xiangheng , Liao Lei , Miao Ling , Wu Wei , Mei Fei , Stepanov Andrey L. , Cai Guangxu , Liu Yong , Dai Zhigao , Ren Feng , Jiang Changzhong , Liu Jiarui
Published: April 2014

Performance of the material depends directly on the electronic and energy band structure, to improve the photoactivity of TiO2 and decrease carrier recombination centers induced by monodoping, the TiO2 thin film has been modified with V and N codopants by ion implantation for tailing and controlling the electronic structure and energy band structure. Compared to monodopant, codopants of V and N exhibit a synergistic effect in the photoactivity enhancement of TiO2. X-ray photoelectron spectroscopy (XPS) studies demonstrate that the implanted V and N ions are introduced into the lattice of TiO2 through V and N substituting Ti and O, respectively. The electronic structure of V/N codoped TiO2 was calculated by First-principles calculations based on density-functional theory, the results show the band edges of TiO2 can be tailored by V and N codopants. UV-vis spectra consistently show the absorption edge of V/N codoped TiO2 film is widen to visible light region. More importantly, the photoactivity of TiO2 film has been significantly improved after V/N codoping. The enhanced photocatalytic performance is believed to be due to the V and N codopants induced synergistic effect that not only enhances the absorption of visible light but also promotes the separation of photogenerated electrons and holes in TiO2. Besides, there exists an optimum for V/N ions implantation fluence. The capability of improving TiO2 photoactivity by V/N codoping could open up new opportunities in the development of highly efficient photocatalysts and photoelectrodes for solar energy and environmental applications.
Trapping helium in Y2Ti2O7 compared to in matrix iron: A first principles study
Authors: Yang Litong , Jiang Yong , Robert Odette G. , Yamamoto Takuya , Liu Zuming , Liu Yong
Published: April 2014

Pyrochlore Y2Ti2O7 is a primary precipitate phase in nano-structured ferritic alloys (NFAs) for fission and fusion energy applications. We report a theoretical study for assessing the relative stability of trapping helium in Y2Ti2O7 versus in matrix iron. Various defect structures and the associated energies are examined and compared. Results reveal that helium can be deeply trapped in Y2Ti2O7 and that the corresponding self-interaction is essentially repulsive. Transmutant helium in NFAs prefers to occupy individual octa-interstitial sites in Y2Ti2O7, before forming small clusters in Y2Ti2O7. Helium partitioning in NFAs depends on the number and dispersion of Y2Ti2O7; and thus initially, bubble formation and growth in iron matrix can be largely suppressed. Charge transfer occurs from helium to neighboring oxygen anions, but not to neighboring metal cations, suggesting a general effectiveness of trapping helium in oxides. Reasons for the ultimate fate of helium to form small nm-scale interface bubbles are also discussed.
Polymer aggregation correlated transition from Schottky-junction to bulk heterojunction organic solar cells
Authors: Yang Bin , Xiao Zhengguo , Huang Jinsong
Published: April 2014

The fullerene-based organic Schottky-junction solar cells have recently attracted intensive research interest because of their unique electrical performance, such as significant photocurrent generation from excitons created in fullerenes and large open-circuit voltage (VOC) output induced by high Schottky-barrier height between the anode and the fullerene acceptor. This manuscript reports another remarkably appealing advantage that the fullerene-based Schottky-junction solar cells are more stable than the bulk heterojunction counterparts. The better stability is likely due to mitigative polymer photo-oxidation and/or little morphological change of active film in the aged Schottky-junction devices. The transition from Schottky-junction to bulk heterojunction appears at polymer donor loading ratio of 20–25 wt. % by examining the variation in the VOC with increased loading ratio of the poly(3-hexylthiophene) donor. Multiple experimental evidences, including the absorbance spectrum measurement, photoluminescence study, active film morphology characterization, and charge mobility measurement, conclusively reveal that the transition from Schottky-junction to bulk heterojunction is correlated to the polymer donor aggregation in the active films.
Ab initio studies of 1,3,5,7-tetranitro-1,3,5,7-tetrazocine/1,3-dimethyl-2-imidazolidinone cocrystal under high pressure using dispersion corrected density functional theory
Authors: Gu Bang-Ming , Lin He , Zhu Shun-Guan
Published: April 2014

A detailed study of structural, electronic, and thermodynamic properties of 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)/1,3-dimethyl-2-imidazolidinone (DMI) cocrystal under the hydrostatic pressure of 0–100 GPa was performed by using dispersion-corrected density functional theory (DFT-D) method. The calculated crystal structure is in reasonable agreement with the experimental data at the ambient pressure. Based on the analysis of lattice constants, bond lengths, bond angles, and dihedral angles under compression, it is found that HMX molecules in HMX/DMI cocrystal are seriously distorted. In addition, as the pressure increases, the band gap decreases gradually, which suggests that HMX/DMI cocrystal is becoming more metallic. Some important intermolecular interactions between HMX and DMI are also observed in the density of states spectrum. Finally, its thermodynamic properties were characterized, and the results show that HMX/DMI cocrystal is more easily formed in the low pressure.
Coordination-resolved local bond contraction and electron binding-energy entrapment of Si atomic clusters and solid skins
Authors: Bo Maolin , Wang Yan , Huang Yongli , Zhang Xi , Zhang Ting , Li Can , Sun Chang Q.
Published: April 2014

Consistency between x-ray photoelectron spectroscopy measurements and density-function theory calculations confirms our bond order-length-strength notation-incorporated tight-binding theory predictions on the quantum entrapment of Si solid skin and atomic clusters. It has been revealed that bond-order deficiency shortens and strengthens the Si-Si bond, which results in the local densification and quantum entrapment of the core and valence electrons. Unifying Si clusters and Si(001) and (111) skins, this mechanism has led to quantification of the 2p binding energy of 96.089 eV for an isolated Si atom, and their bulk shifts of 2.461 eV. Findings evidence the significance of atomic undercoordination that is of great importance to device performance.
Ultrafast single-electron transfer in coupled quantum dots driven by a few-cycle chirped pulse
Authors: Yang Wen-Xing , Chen Ai-Xi , Bai Yanfeng , Lee Ray-Kuang
Published: April 2014

We theoretically study the ultrafast transfer of a single electron between the ground states of a coupled double quantum dot (QD) structure driven by a nonlinear chirped few-cycle laser pulse. A time-dependent Schrödinger equation without the rotating wave approximation is solved numerically. We demonstrate numerically the possibility to have a complete transfer of a single electron by choosing appropriate values of chirped rate parameters and the intensity of the pulse. Even in the presence of the spontaneous emission and dephasing processes of the QD system, high-efficiency coherent transfer of a single electron can be obtained in a wide range of the pulse parameters. Our results illustrate the potential to utilize few-cycle pulses for the excitation in coupled quantum dot systems through the nonlinear chirp parameter control, as well as a guidance in the design of experimental implementation.
Aperiodic signals processing via parameter-tuning stochastic resonance in a photorefractive ring cavity
Authors: Li Xuefeng , Cao Guangzhan , Liu Hongjun
Published: April 2014

Based on solving numerically the generalized nonlinear Langevin equation describing the nonlinear dynamics of stochastic resonance by Fourth-order Runge-Kutta method, an aperiodic stochastic resonance based on an optical bistable system is numerically investigated. The numerical results show that a parameter-tuning stochastic resonance system can be realized by choosing the appropriate optical bistable parameters, which performs well in reconstructing aperiodic signals from a very high level of noise background. The influences of optical bistable parameters on the stochastic resonance effect are numerically analyzed via cross-correlation, and a maximum cross-correlation gain of 8 is obtained by optimizing optical bistable parameters. This provides a prospective method for reconstructing noise-hidden weak signals in all-optical signal processing systems.
Measurement of high frequency conductivity of oxide-doped anti-ferromagnetic thin film with a near-field scanning microwave microscope
Authors: Wu Z. , Souza A. D. , Peng B. , Sun W. Q. , Xu S. Y. , Ong C. K.
Published: April 2014

In this manuscript, we describe how the map of high frequency conductivity distribution of an oxide-doped anti-ferromagnetic 200 nm thin film can be obtained from the quality factor (Q) measured by a near-field scanning microwave microscope (NSMM). Finite element analysis (FEA) is employed to simulate the NSMM tip-sample interaction and obtain a curve related between the simulated quality factor (Q) and conductivity. The curve is calibrated by a standard Cu thin film with thickness of 200 nm, together with NSMM measured Q of Ag, Au, Fe, Cr and Ti thin films. The experimental conductivity obtained by the NSMM for IrMn thin films with various doped concentrations of Al2O3 is found consistent with conventional voltammetry measurement in the same tendency. That conductivity decreases as the content of doped Al2O3 increases. The results and images obtained demonstrate that NSMM can be employed in thin film analysis for characterization of local electrical properties of materials in a non-destructive manner and for obtaining a map of conductivity distribution on the same film.
Nanowire-based ternary transistor by threshold-voltage manipulation
Authors: Han Junebeom , Lim Taekyung , Bong Jihye , Seo Keumyoung , Kim Sunkook , Ju Sanghyun
Published: April 2014

We report on a ternary device consisting of two nanowire channels that have different threshold voltage (Vth) values and show that three current stages can be produced. A microscale laser-beam shot was utilized to selectively anneal the nanowire channel area to be processed, and the amount of Vth shift could be controlled by adjusting the laser wavelength. Microscale laser annealing process could control Vth of the individual nanowire transistors while maintaining the other parameters the constant, such as the subthreshold slope, on–off current ratio, and mobility. This result could provide a potential for highly integrated and high-speed ternary circuits.
Influence of globulin subunit composition of soybean proteins on silken tofu quality. 2. Absence of 11SA4 improves the effect of protein content on tofu hardness
Authors: James Andrew T. , Yang Aijun
Published: April 2014

Soybean variety Bunya was developed in Australia to provide a better quality bean for tofu manufacturers. It is null for globulin subunit 11SA4. We investigated the effect of both the Bunya genetic background and the11SA4 subunit on tofu properties using genotypes containing 11SA4, with and without Bunya parentage, or lacking 11SA4 with Bunya parentage. Both Bunya parentage and 11SA4 significantly influenced globulin subunit composition and tofu texture. The group lacking 11SA4 had lower seed protein content, the largest seeds and the highest 7S and the lowest 11S content and produced the hardest tofu. Examination of the impact of 11SA4 null on tofu texture at four protein contents (380–440 g kg–1) over four coagulant (2.0–3.5 g kg–1) levels revealed that the absence of 11SA4 produced firmer tofu across the protein and coagulation levels tested, and this difference was larger than that from higher protein or coagulation levels. These results demonstrated that the absence of the 11SA4 subunit could increase tofu hardness to a level that otherwise could only be achieved with much higher seed protein content.
Reasonableness, Rationality and Government: The Liberal Political Thought of Mehdi Ha’eri Yazdi
Authors: Badamchi Meysam
Published: April 2014

Rawls formulates liberalism according to two conceptions of reasonable and rational, which, tied to two particular notions of society and person, define the basis of liberalism in Rawlsian thought. This article argues that Mehdi Haeri Yazdi's important work,Hekmat va Hokumaat,should be considered as a work of liberal theory, and shows how it endorses liberal conceptions of the reasonable and the rational. The main elements of Ha'eri's liberalism are his thesis that philosophy has priority over jurisprudence, his doctrine of contract based upon concepts of agency contract (aqd-e vekalat) and joint private ownership (malekiyat-e shakhsi-ye musha), and his defense of individualism against the alleged collectivism of Rousseau.
Metabolic engineering of Saccharomyces cerevisiae to improve succinic acid production based on metabolic profiling
Authors: Ito Yuma , Hirasawa Takashi , Shimizu Hiroshi
Published: April 2014

We performed metabolic engineering on the budding yeast Saccharomyces cerevisiae for enhanced production of succinic acid. Aerobic succinic acid production in S. cerevisiae was achieved by disrupting the SDH1 and SDH2 genes, which encode the catalytic subunits of succinic acid dehydrogenase. Increased succinic acid production was achieved by eliminating the ethanol biosynthesis pathways. Metabolic profiling analysis revealed that succinic acid accumulated intracellularly following disruption of the SDH1 and SDH2 genes, which suggests that enhancing the export of intracellular succinic acid outside of cells increases succinic acid production in S. cerevisiae. The mae1 gene encoding the Schizosaccharomyces pombe malic acid transporter was introduced into S. cerevisiae, and as a result, succinic acid production was successfully improved. Metabolic profiling analysis is useful in producing chemicals for metabolic engineering of microorganisms.
Effects of various emulsification methods on the oxidation of methyl linoleate
Authors: Ma Tiezheng , Kobayashi Takashi , Adachi Shuji
Published: April 2014

The effects of mechanical stress during emulsification on the oxidation of methyl linoleate were investigated by four methods (high-pressure homogenization, high-speed stirring, ultrasonic homogenization, and membrane emulsification). The oxidation rates and induction periods were almost constant, regardless of the emulsification method, except for membrane emulsification, by which the induction period was prolonged when a cellulose acetate membrane was used.
Anti-proliferative activity of 6-O-acyl-d-allose against the human leukemia MOLT-4F cell line
Authors: Yanagita Ryo C , Kobashi Katsuya , Ogawa Chisa , Ashida Yoshiki , Yamaashi Haruka , Kawanami Yasuhiro
Published: April 2014

The anti-proliferative activities of the 6-O-acyl derivatives of d-allose against the human leukemia MOLT-4F cell line were examined. The activity of the 6-O-dodecanoyl derivative (3) was approximately 30 times stronger than that of d-allose. An evaluation of the derivatives of 3 that occurred in a furanose form revealed the pyranose forms of 3 to be important for the anti-proliferative activity.
A new life for an old pump: V-ATPase and neurotransmitter release
Authors: Vavassori Stefano , Mayer Andreas
Published: April 2014

Neurons fire by releasing neurotransmitters via fusion of synaptic vesicles with the plasma membrane. Fusion can be evoked by an incoming signal from a preceding neuron or can occur spontaneously. Synaptic vesicle fusion requires the formation of trans complexes between SNAREs as well as Ca2+ ions. Wang et al. (2014. J. Cell Biol. http://dx.doi.org/jcb.201312109) now find that the Ca2+-binding protein Calmodulin promotes spontaneous release and SNARE complex formation via its interaction with the V0 sector of the V-ATPase.
Prognostic Significance of Standardized Uptake Value of Lymph Nodes on Survival for Stage III Non-small Cell Lung Cancer Treated With Definitive Concurrent Chemoradiotherapy
Authors: Lee Victor H.F. , Chan Wendy W.L. , Lee Elaine Y.P. , Choy Tim-Shing , Ho Patty P.Y. , Leung Dennis K.C. , Lam Ka-On , Kwong Dora L.W. , Leung To-Wai , Khong Pek-Lan
Published: April 2014

Objectives:

Definitive concurrent chemoradiotherapy is the standard treatment for stage III non–small cell lung cancer (NSCLC). Previous studies showed that the tumor size and its metabolic activity are predictors of treatment outcome. We investigated whether there are new metabolic prognostic factors of survival for stage III NSCLC after definitive concurrent chemoradiotherapy.

Patients and Methods:

A total of 57 consecutive patients treated with definitive concurrent chemoradiotherapy for their stage IIIA (n=22) and stage IIIB (n=35) (AJCC 7th edition) unresectable NSCLC were identified. A total of 43 (75.4%) patients had positron emission tomography with integrated computed tomography (PET-CT) scan performed at diagnosis that were subsequently reviewed and analyzed. Prognosticators of progression-free survival (PFS), distant metastasis-free survival (DMFS), and overall survival (OS) were analyzed.

Results:

The median PFS, DMFS, and OS were 14.1, 12.6, and 37.8 months, respectively, after a median follow-up of 41.5 months. PFS advantage was demonstrated in stage IIIA versus stage IIIB (median 38.6 vs. 13.5 mo, P=0.020), N-stage N0-N2 versus N3 (median 16.7 vs. 8.1 mo, P<0.001), planning target volume (PTV) <500 versus ≥500 cm3 (median 23.6 vs. 11.3 mo, P=0.008), and the maximum standardized uptake value (SUVmax) nodes <8 versus ≥8 (median 16.1 vs. 10.7 mo, P=0.048). DMFS advantage was noted in those with PTV<500 versus PTV≥500 cm3 (median 13.0 vs. 11.3 mo, P=0.045) and SUVmax nodes <8 versus ≥8 (median 13.5 vs. 8.0 mo, P=0.050). OS advantage was revealed in stage IIIA versus stage IIIB (median 56.5 vs. 22.7 mo, P=0.013) and SUVmax nodes <8 versus ≥8 (42.3 vs. 12.8 mo, P=0.009). Multivariate analysis demonstrated that SUVmax nodes <8 was the only prognostic factor of PFS, DMFS, and OS. Metabolic tumor volume and total lesion glycolysis were not prognostic factors.

Conclusions:

SUVmax nodes <8 was the only prognostic factor of PFS, DMFS, and OS in our study. PET-CT scan at the time of diagnosis is useful in stratifying patients into favorable and unfavorable groups in stage III NSCLC treated with definitive concurrent chemoradiotherapy.
Dramatic Response to Catumaxomab Treatment for Malign Ascites Related to Renal Cell Carcinoma With Sarcomotoid Differentiation
Authors: Pilancı Kezban Nur , Ordu Çetin , Akpınar Haluk , Balcı Cem , Başsülü Nuray , Köksal Ülkühan İner , Elbüken Filiz , Okutur Kerem , Bülbül Gülen , Sağlam Sezer , Demir Gökhan
Published: April 2014

Refractory malignant ascites (MA) is a common complication in cancer patients. Renal cell carcinoma (RCC) is rarely present with peritoneal ascites, which is commonly associated with carcinomas of the gastrointestinal and female reproductive tracts; including especially ovarian high-grade serous carcinoma. Currently, chemotherapy and paracentesis represent the most widely used methods to relieve the symptoms. Recently, intraperitoneal therapy with catumaxomab—a trifunctional hybrid antibody—has been introduced for the treatment of MA. The benefit of this treatment has been demonstrated in patients with distinct abdominal malignancies. In this case report, we present the first case of successful catumaxomab treatment against MA in a patient with advanced RCC with sarcomatoid differentiation. After the second administration of catumaxomab, paracentesis became no longer necessary. Catumaxomab might represent a safe treatment option for MA in the course of metastatic RCC with sarcomatoid differentiation.
Epigenetic Landscape Models: The Post-Genomic Era
Authors: Davila-Velderrain Jose , Martinez-Garcia Juan Carlos , Alvarez-Buylla Elena R
Published: April 2014

Complex networks of regulatory interactions orchestrate developmental processes in multicellular organisms. Such a complex internal structure intrinsically constrains cellular behavior allowing only a reduced set of attainable and observable cellular states or cell types. Thus, a multicellular system undergoes cell fate decisions in a robust manner in the course of its normal development. The epigenetic landscape (EL) model originally proposed by C.H. Waddington was an early attempt to integrate these processes in a universal conceptual model of development. Since then, a wealth of experimental data has accumulated, the general mechanisms of gene regulation have been uncovered, and the placement of specific molecular components within modular gene regulatory networks (GRN) has become a common practice. This has motivated the development of mathematical and computational models inspired by the EL aiming to integrate molecular data and gain a better understanding of development, and hopefully predict cell differentiation and reprogramming events. Both deterministic and stochastic dynamical models have been used to described cell state transitions. In this review, we describe recent EL models, emphasising that the construction of an explicit landscape from a GRN is not the only way to implement theoretical models consistent with the conceptual basis of the EL. Moreover, models based on the EL have been shown to be useful in the study of morphogenic processes and not just cell differentiation. Here we describe the distinct approaches, comparing their strengths and weaknesses and the kind of biological questions that they have been able to address. We also point to challenges ahead.
Purification, crystallization and preliminary crystallographic analysis of a ribosome-recycling factor fromThermoanaerobacter tengcongensis(TteRRF)
Authors: Shang Guijun , Feng Duo , Lu Fang , Zhang Hongjie , Cang Huaixing , Gao Wei , Bi Ruchang
Published: April 2014

Ribosome-recycling factor (RRF) plays an essential role in the fourth step of protein synthesis in prokaryotes. RRF combined with elongation factor G (EF-G) disassembles the post-termination ribosome complex and recycles the protein synthesis machine for the next round of translation. A reductive-methylation-modified RRF fromThermoanaerobacter tengcongensis(TteRRF) has been crystallized using the vapour-diffusion method. The crystal grew in a condition consisting of 0.1 Mcitric acid pH 3.5, 3.0 MNaCl and 50 mg ml−1methylated protein solution at 289 K. A complete data set was collected from a crystal to 2.80 Å resolution using synchrotron radiation at 100 K. The crystal belonged to space groupP6122/P6522 with unit-cell parametersa=b= 103.26,c= 89.17 Å. The asymmetric unit was estimated to contain one molecule ofTteRRF.
Structure of theArabidopsis thalianaTOP2 oligopeptidase
Authors: Wang Ruiying , Rajagopalan Krithika , Sadre-Bazzaz Kianoush , Moreau Magali , Klessig Daniel F. , Tong Liang
Published: April 2014

Thimet oligopeptidase (TOP) is a zinc-dependent metallopeptidase. Recent studies suggest thatArabidopsis thalianaTOP1 and TOP2 are targets for salicylic acid (SA) binding and participate in SA-mediated plant innate immunity. The crystal structure ofA. thalianaTOP2 has been determined at 3.0 Å resolution. Comparisons to the structure of human TOP revealed good overall structural conservation, especially in the active-site region, despite their weak sequence conservation. The protein sample was incubated with the photo-activated SA analog 4-azido-SA and exposed to UV irradiation before crystallization. However, there was no conclusive evidence for the binding of SA based on the X-ray diffraction data. Further studies are needed to elucidate the molecular mechanism of how SA regulates the activity ofA. thalianaTOP1 and TOP2.
Expression, purification, crystallization and preliminary crystallographic study of the cytoplasmic domain of the mitochondrial dynamics protein MiD51
Authors: Ma Jun , Sun Fei
Published: April 2014

Mitochondria play central roles in many cellular and physiological processes. They are highly dynamic organelles and continually undergo fusion and fission. Mitochondrial dynamics protein 51 kDa (MiD51), an integral mitochondrial outer membrane protein, recruits dynamin-related protein 1 (Drp1; a mitochondrial fission protein) to mitochondria and facilitates Drp1-directed mitochondrial fission. In this study, the cytoplasmic domain of MiD51 was overexpressed inEscherichia coli, purified and crystallized. An X-ray diffraction data set was collected to a resolution of 3.1 Å and the crystal belonged to space groupP41212, with unit-cell parametersa=b= 90.1,c= 124.7 Å, α = β = γ = 90°. The asymmetric unit had the highest probability of containing one molecule, with a Matthews coefficient of 3.32 Å3 Da−1and a solvent content of 63.0%.
Spatial distribution analyses of natural phyllosphere‐colonizing bacteria on Arabidopsis thaliana revealed by fluorescence in situ hybridization
Authors: Remus‐Emsermann Mitja N. P. , Lücker Sebastian , Müller Daniel B. , Potthoff Eva , Daims Holger , Vorholt Julia A.
Published: April 2014

Bacterial colonizers of the aerial parts of plants, or phyllosphere, have been identified on a number of different plants using cultivation‐dependent and independent methods. However, the spatial distribution at the micrometer scale of different main phylogenetic lineages is not well documented and mostly based on fluorescence‐tagged model strains. In this study, we developed and applied a spatial explicit approach that allowed the use of fluorescence in situ hybridization (FISH) to study bacterial phylloplane communities of environmentally grown Arabidopsis thaliana. We found on average 5.4 × 106 bacteria cm−2 leaf surface and 1.5 × 108 bacteria g−1 fresh weight. Furthermore, we found that the total biomass in the phylloplane was normally distributed. About 31% of the bacteria found in the phylloplane did not hybridize to FISH probes but exhibited infrared autofluorescence indicative for aerobic anoxygenic phototrophs. Four sets of FISH probes targeting Alphaproteobacteria, Betaproteobacteria, Actinobacteria and Bacteroidetes were sufficient to identify all other major contributors of the phylloplane community based on general bacterial probing. Spatial aggregation patterns were observed for all probe‐targeted populations at distances up to 7 μm, with stronger tendencies to co‐aggregate for members of the same phylogenetic group. Our findings contribute to a bottom‐up description of leaf surface community composition.
Phytochrome controls conidiation in response to red/far‐red light and daylight length and regulates multistress tolerance in Beauveria bassiana
Authors: Qiu Lei , Wang Juan‐Juan , Chu Zhen‐Jian , Ying Sheng‐Hua , Feng Ming‐Guang
Published: April 2014

Phytochromes (Phy) in filamentous fungi are Group VIII histidine kinases that share a unique N‐terminal photosensory core, but their functions are largely unknown. Here we show that Beauveria bassiana Phy (Bbphy) is functionally vital for growth, conidiation and multistress tolerance of the fungal entomopathogen lacking sexual stage. Colony growth of ΔBbphy was significantly slower in a nutrition‐rich medium but faster in several minimal media. Conidial yield of ΔBbphy in the rich medium increased at the fitted rate of 3.4 × 107 conidia h−1 white light in the light/dark cycles of 0:24 to 16:8 h, decreased greatly in the short‐, long‐ and full‐day cycles of red/far‐red light, but was unaffected under full‐day blue light. Moreover, ΔBbphy showed higher osmosensitivity, increased antioxidant capability, and decreased conidial thermotolerance and UV‐B resistance, accompanied with downregulation of Hog1 phosphorylation and of four Hog1‐related genes under osmotic stress, and upregulation of five superoxide dismutases and four catalases under oxidative stress. All the changes were restored by the gene complementation. Taken together, Bbphy controls conidiation by responding to daylight length and red/far‐red light and regulates multistress responses perhaps because of an involvement in Hog1 pathway. Our findings highlight diverse functions of Bbphy in B. bassiana.
International Strategy and Knowledge Creation: The Advantage of Foreignness and Liability of Concentration
Authors: Regnér Patrick , Zander Udo
Published: April 2014

International business scholars increasingly emphasize regional strategies based on an optimal location of downstream sales. There has been less scholarly attention, however, to the relationship between international strategy and upstream knowledge creation including R&D. Building on contemporary strategic management theory and the knowledge‐based view we remedy this. The viability of home‐regional or bi‐regional strategies is based on common assumptions that imply negative consequences of distance and foreignness for downstream sales and marketing and benefits from agglomeration for upstream knowledge creation activities including R&D. In contrast, we propose that upstream knowledge creation, radical innovation in particular, rather gains from distance and foreignness and from being dispersed, suggesting the effectiveness of a global strategy. Based on the resource‐based view and recent research on the economics of strategic opportunities and competitive advantage, we provide theoretical explanations for this. We demonstrate how a global multinational corporation is uniquely equipped with knowledge extensity including heterogeneous social‐identity frames in multiple sub‐units. Thanks to arbitrage advantages between the sub‐units’ separate and often locally embedded knowledge, a global multinational corporation can address complex interdependences and interactions between knowledge sets required for knowledge creation. This suggests that maximum exploration capabilities are made possible by a global rather than a home‐regional or bi‐regional strategy.
‘The Cliffs are not Cliffs’: The Cliffs ofDover and National Identities inBritain,c.1750–c.1950
Authors: Readman Paul
Published: April 2014

This article examines the relationship between landscape andBritish national identities by means of a case study of the white cliffs ofDover inKent,England. The cliffs were important symbols of island‐nationhood across the modern period, and demonstrate that even in the age of empireBritish as well asEnglish national identities could be conceptualized in distinctly insular ways. In particular, the cliffs were seen to be associated with the national homeland, its heritage and historical continuity over hundreds of years, as well as with national defence and a defiant self‐asserted separateness from the rest ofEurope. The article has implications for the (still relatively neglected) role played by specific landscapes in the construction of national identities, not just inBritain but generally. In functioning as markers of national difference the physical distinctiveness of these landscapes was important, but their associational value mattered more.
Pharmacokinetics of dexmedetomidine combined with therapeutic hypothermia in a piglet asphyxia model
Authors: EZZATI M. , BROAD K. , KAWANO G. , FAULKNER S. , HASSELL J. , FLEISS B. , GRESSENS P. , FIERENS I. , ROSTAMI J. , MAZE M. , SLEIGH J. W. , ANDERSON B. , SANDERS R. D. , ROBERTSON N. J.
Published: April 2014

Background

The highly selective α2‐adrenoreceptor agonist, dexmedetomidine, exerts neuroprotective, analgesic, anti‐inflammatory and sympatholytic properties that may be beneficial for perinatal asphyxia. The optimal safe dose for pre‐clinical newborn neuroprotection studies is unknown.

Methods

Following cerebral hypoxia‐ischaemia, dexmedetomidine was administered to nine newborn piglets in a de‐escalation dose study in combination with hypothermia (whole body cooling to 33.5°C). Dexmedetomidine was administered with a loading dose of 1 μg/kg and maintenance infusion at doses from 10 to 0.6 μg/kg/h. One additional piglet was not subjected to hypoxia‐ischaemia. Blood for pharmacokinetic analysis was sampled pre‐insult and frequently post‐insult. A one‐compartment linear disposition model was used to fit data. Population parameter estimates were obtained using non‐linear mixed effects modelling.

Results

All dexmedetomidine infusion regimens led to plasma concentrations above those associated with sedation in neonates and children (0.4–0.8 μg/l). Seven out of the nine piglets with hypoxia‐ischaemia experienced periods of bradycardia, hypotension, hypertension and cardiac arrest; all haemodynamic adverse events occurred in piglets with plasma concentrations greater than 1 μg/l. Dexmedetomidine clearance was 0.126 l/kg/h [coefficient of variation (CV) 46.6.%] and volume of distribution was 3.37 l/kg (CV 191%). Dexmedetomidine clearance was reduced by 32.7% at a temperature of 33.5°C. Dexmedetomidine clearance was reduced by 55.8% following hypoxia‐ischaemia.

Conclusions

Dexmedetomidine clearance was reduced almost tenfold compared with adult values in the newborn piglet following hypoxic‐ischaemic brain injury and subsequent therapeutic hypothermia. Reduced clearance was related to cumulative effects of both hypothermia and exposure to hypoxia. High plasma levels of dexmedetomidine were associated with major cardiovascular complications.
Essential role for the TRF2 telomere protein in adult skin homeostasis
Authors: Martínez Paula , Ferrara‐Romeo Iole , Flores Juana M. , Blasco Maria A.
Published: April 2014

TRF2 is a component of shelterin, the protein complex that protects the ends of mammalian chromosomes. TRF2 is essential for telomere capping owing to its roles in suppressing an ATM‐dependent DNA damage response (DDR) at chromosome ends and inhibiting end‐to‐end chromosome fusions. Mice deficient for TRF2 are early embryonic lethal. However, the role of TRF2 in later stages of development and in the adult organism remains largely unaddressed, with the exception of liver, where TRF2 was found to be dispensable for maintaining tissue function. Here, we study the impact of TRF2 conditional deletion in stratified epithelia by generating the TRF2∆/∆‐K5‐Cre mouse model, which targets TRF2 deletion to the skin from embryonic day E11.5. In marked contrast to TRF2 deletion in the liver, TRF2∆/∆‐K5‐Cre mice show lethality in utero reaching 100% lethality perinataly. At the molecular and cellular level, TRF2 deletion provokes induction of an acute DDR at telomeres, leading to activation of p53 signaling pathways and to programed cell death since the time of Cre expression at E11.5. Unexpectedly, neither inhibition of the NHEJ pathway by abrogation of 53BP1 nor inhibition of DDR by p53 deficiency rescued these severe phenotypes. Instead, TRF2 deletion provokes an extensive epidermal cell death accompanied by severe inflammation already at E16.5 embryos, which are independent of p53. These results are in contrast with conditional deletion of TRF1 and TPP1 in the skin, where p53 deficiency rescued the associated skin phenotypes, highlighting the comparatively more essential role of TRF2 in skin homeostasis.
Crematogaster chiarinii ants as a potential biological control agent for protecting honeybee colonies from attack by Dorylus quadratus driver ants in Ethiopia (Hymenoptera: Formicidae)
Authors: Adgaba Nuru , Shenkute Awraris G. , Al‐Ghamdi Ahmed A. , Assefa Amenay , Ansari Mohammad J. , Taylor Brian , Radloff Sarah
Published: April 2014

Driver ants of the genus Dorylus are well known across tropical Africa for their aggressive foraging swarms. Although these swarms have beneficial effects in clearing out invertebrate pests; they destroy thousands of honeybee colonies and, accordingly, cause significant economic losses.

Fear of driver ant attack leads most beekeepers in tropical Africa to hang their beehives high up on trees, making proper bee management difficult and limiting the involvement of women and the elderly.

In Ethiopia, forest beekeepers have recognized that beehives hung on trees containing nests of an arboreal ant Crematogaster chiarinii Emery 1881 remain safe from invasion by swarms of a driver ant Dorylus quadratus Santschi 1914. In the present study, we report investigations into the mode and efficacy of the C. chiarinii defence system, as well as the potential for increasing its populations and enhancing this biological protection.
Against Anonymity
Authors: Baker Robert
Published: April 2014

In ‘New Threats to Academic Freedom’ Francesca Minerva argues that anonymity for the authors of controversial articles is a prerequisite for academic freedom in the Internet age. This argument draws its intellectual and emotional power from the author's account of the reaction to the on‐line publication of ‘ After‐birth abortion: why should the baby live?’ – an article that provoked cascades of hostile postings and e‐mails. Reflecting on these events, Minerva proposes that publishers should offer the authors of controversial articles the option of publishing their articles anonymously. This response reviews the history of anonymous publication and concludes that its reintroduction in the Internet era would recreate problems similar to those that led print journals to abandon the practice: corruption of scholarly discourse by invective and hate speech, masked conflicts of interest, and a diminution of editorial accountability. It also contends that Minerva misreads the intent of the hostile e‐mails provoked by ‘After‐birth abortion,’ and that ethicists who publish controversial articles should take responsibility by dialoguing with their critics – even those whose critiques are emotionally charged and hostile.
EPH receptor/ephrin system: in the quest for novel anti‐angiogenic therapies: Commentary on Hassan‐Mohamed et al., Br J Pharmacol 171: 5195–5208
Authors: Hatziapostolou M , Polytarchou C
Published: April 2014

Linked Article

This article is a Commentary on Hassan‐Mohamed I, Giorgio C, Incerti M, Russo S, Pala D, Pasquale EB, Zanotti I, Vicini P, Barocelli E, Rivara S, Mor M, Lodola A and Tognolini M (2014). UniPR129 is a competitive small molecule Eph‐ephrin antagonist blocking in vitro angiogenesis at low micromolar concentrations. Br J Pharmacol 171: 5195–5208. doi: 10.1111/bph.12669