bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased FSHD region gene1 expression reduces in vitro cell migration, invasion, and angiogenesis, ex vivo supported by reduced expression in tumors
Authors: Tiwari Ankit , Pattnaik Niharika , Mohanty Jaiswal Archita  , Dixit Manjusha
Published: September 2017

Facioscapulohumeral muscular dystrophy (FSHD) region gene 1 (FRG1) is a candidate gene for FSHD. FRG1 regulates various muscle-related functions, but studies have proposed its role in development and angiogenesis also, where it is involved with tumor-associated molecules. Therefore, we decided to look into its role in tumor progression, tumor angiogenesis, and its impact on cellular properties. Cell proliferation, migration, invasion and in vitro angiogenesis assays were performed to decipher the effect of FRG1 on endothelial and epithelial cell functions. Q-RT PCR was done for human embyonic kidney (HEK293T) cells with altered FRG1 levels to identify associated molecules. Further, immunohistochemistry was done to identify FRG1 expression levels in various cancers and its association with tumor angiogenesis. Subsequently, inference was drawn from Oncomine and Kaplan–Meier plotter analysis, for FRG1 expression in different cancers. Ectopic expression of FRG1 affected cell migration and invasion in both HEK293T and human umbilical vein endothelial cells (HUVECs). In HUVECs, FRG1 overexpression led to reduced angiogenesis in vitro. No effect was observed in cell proliferation in both the cell types. Q-RT PCR data revealed reduction in granulocyte-colony stimulating factor (G-CSF) expression with FRG1 overexpression and increased expression of matrix metalloproteinase 10 (MMP10) with FRG1 knockdown. Immunohistochemistry analysis showed reduced FRG1 levels in tumors which were supported by in silico analysis data. These findings suggest that reduction in FRG1 expression in gastric, colon and oral cavity tumor might have a role in tumor progression, by regulating cell migration and invasiveness. To elucidate a better understanding of molecular signaling involving FRG1 in angiogenesis regulation, further study is required.
Cooperative resource management and power allocation for multiuser OFDMA networks
Authors: Yassin Mohamad , Lahoud Samer , Ibrahim Marc , Khawam Kinda , Mezher Dany , Cousin Bernard
Published: September 2017

Mobile network operators are facing the challenge to increase network capacity and satisfy the growth in data traffic demands. In this context, long‐term evolution (LTE) networks, LTE‐advanced networks, and future mobile networks of the fifth generation seek to maximise spectrum profitability by choosing the frequency reuse‐1 model. Owing to this frequency usage model, advanced radio resource management and power allocation schemes are required to avoid the negative impact of interference on system performance. Some of these schemes modify resource allocation between network cells, while others adjust both resource and power allocation. In this study, the authors introduce a cooperative distributed interference management algorithm, where resource and power allocation decisions are jointly made by each cell in collaboration with its neighbouring cells. Objectives sought are: increasing user satisfaction, improving system throughput, and increasing energy efficiency. The proposed technique is compared with the frequency reuse‐1 model and to other state‐of‐the‐art techniques under uniform and non‐uniform user distributions and for different network loads. They address scenarios where throughput demands are homogeneous and non‐homogeneous between network cells. System‐level simulation results demonstrate that their technique succeeds in achieving the desired objectives under various user distributions and throughput demands.
Self‐deployed wireless actor networks with maximal task satisfaction
Authors: Baroudi Uthman , Sallam Gamal , Al‐Shaboti Mohammed , Younis Mohamed
Published: September 2017

Deploying a networked set of robots is an effective way to serve applications in environments where human intervention is impossible or possess risks. For example, a team of robots can assist rescuers to map, navigate indoor hazardous areas in rescue operation. Collaboration among the robots is very essential in these applications in order to efficiently achieve the aimed goals in a timely manner. Realising such a collaborative operation autonomously in the absence of GPS services is a challenge. This study tackles this challenge assuming sensors/landmarks are present in the deployment area. Each sensor/landmark requires a specific number of robots to perform certain tasks. A spatial–temporal coverage solution is pursued to maintain connectivity and overcome the shortage of available robots. Dynamic coverage problem is formulated as potential fields where landmarks and nodes exert virtual forces among each other based on coverage demand and overlapped area. The proposed approach has been validated through extensive simulation using NS3 simulator and real experimentation using EV3 robots. The proposed approached has shown maximal task satisfaction compared with random waypoint and very close behaviour compared with a centralised approach (Hungarian method).
OFDM‐based spectrum‐aware routing in underwater cognitive acoustic networks
Authors: Ghafoor Huma , Noh Youngtae , Koo Insoo
Published: September 2017

With the long propagation delay of an acoustic signal in underwater communications systems, relay node selection is one of the key design factors, because it significantly improves end‐to‐end delay, thereby improving overall network performance. To this end, the authors propose orthogonal frequency division multiplexing‐based spectrum‐aware routing (OSAR), a scheme in which spectrum sensing is done by an energy detector, and each sensor node broadcasts its local sensing results to all one‐hop nodes via an extended beacon message. Each sensor node then selects nodes that agree on an idle channel, consequentially forming a set of neighbouring nodes. The selection of a relay node is determined by calculating the transmission delay – the source/relay node selected is the one that has the minimum transmission delay from among all nodes in the neighbouring set. To evaluate OSAR, the authors perform extensive simulations via ns‐MIRACLE for different numbers of channels using a BELLHOP model, and evaluate the average delay for different sensor nodes within the considered network. The results show a substantial decrease in delay as the number of sensor nodes increases in the network. In addition, the authors verify that the packet delivery ratio increases with increases in the number of sensor nodes, and prove better performance in the overhead ratio. The authors' simulation results verify that OSAR outperforms existing solutions.
Cu3 P nanotubes: controlled synthesis and their good photocatalytic activity for organic dye
Authors: Liu Shuling , Liu Chao , Guo Jie , Yan Wei
Published: September 2017

Copper phosphide (Cu3 P) nanotubes were successfully synthesised via a facile solvothermal route. The characterisation and analysis results indicate that the as‐prepared sample is composed of a large quantity of Cu3 P nanotubes with the mean diameter of about 100 nm, some nanotubes pass across each other and form the right angle morphology. Moreover, these nanotubes (sample II) can easily be changed to some irregular particles (sample I) or hollow spherical nanostructures (sample III) when the amount of cetyltrimethylammonium bromide is controlled in the experiments. Choosing methylene blue (MB) as a typical organic dye, Cu3 P nanotubes exhibit a good photocatalytic activity, which may be that its large specific surface area enhances the oxidation–reduction ability of electron–hole.
Distribution of shape elongations of main belt asteroids derived from Pan-STARRS1 photometry
Authors: Cibulková H. , Nortunen H. , Ďurech J. , Kaasalainen M. , Vereš P. , Jedicke R. , Wainscoat R. J. , Mommert M. , Trilling D. E. , Schunová-Lilly E. , Magnier E. A. , Waters C. , Flewelling H.
Published: September 2017

Context. A considerable amount of photometric data is produced by surveys such as Pan-STARRS, LONEOS, WISE, or Catalina. These data are a rich source of information about the physical properties of asteroids. There are several possible approaches for using these data. Light curve inversion is a typical method that works with individual asteroids. Our approach in focusing on large groups of asteroids, such as dynamical families and taxonomic classes, is statistical; the data are not sufficient for individual models.

Aim. Our aim is to study the distributions of shape elongation b∕a and the spin axis latitude β for various subpopulations of asteroids and to compare our results, based on Pan-STARRS1 survey, with statistics previously carried out using various photometric databases, such as Lowell and WISE.

Methods. We used the LEADER algorithm to compare the b∕a and β distributions for various subpopulations of asteroids. The algorithm creates a cumulative distributive function (CDF) of observed brightness variations, and computes the b∕a and β distributions with analytical basis functions that yield the observed CDF. A variant of LEADER is used to solve the joint distributions for synthetic populations to test the validity of the method.

Results. When comparing distributions of shape elongation for groups of asteroids with different diameters D, we found that there are no differences for D < 25 km. We also constructed distributions for asteroids with different rotation periods and revealed that the fastest rotators with P = 0 − 4 h are more spheroidal than the population with P = 4−8 h.
Synthesis of Tetraarylmethanes by the Triflic Acid-Promoted Formal Cross-Dehydrogenative Coupling of Triarylmethanes with Arenes
Authors: Nambo Masakazu , Yim Jacky , Fowler Kevin , Crudden Cathleen
Published: September 2017

The formal cross-dehydrogenative coupling of triarylmethanes with arenes promoted by triflic acid and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone is described. This method provides a variety of tetraarylmethane derivatives in good to excellent yields from triarylmethanes that can be readily prepared by our previous methods. Control experiments suggest a possible catalytic cycle involving the generation of a trityl cation intermediate followed by nucleophilic addition of the arene.
Cyclical Remedy Complexes: Their Origin within Traditional Chinese Medicine and Relevance for Miasmatic Theory
Authors: Kantor Jerry
Published: September 2017

The roots of cyclical remedy analysis within traditional Chinese medicine's Five Phases theory are introduced. Relevance for clinical practice including illness interpretation, preventive application via a self-diagnosis mandala, and a more coherent understanding of the five original miasms (expressing five core existential dilemmas) are explained. This article presents a case illustration of anorexia nervosa and an analysis of three conditions: Alzheimer's disease, cancer of the breast, and cancer of the large intestine.
Arthritis Progression on Serial MRIs Following Diagnosis of Medial Meniscal Posterior Horn Root Tear
Authors: Johnson Nick , Mohan Rohith , Hevesi Mario , Stuart Michael , Littrell Laurel , Collins Mark , Krych Aaron
Published: September 2017

Medial meniscus posterior root tears (MMPRTs) are a significant source of pain and dysfunction. The purpose of this study was to evaluate changes in the medial compartment of the knee over time following the diagnosis of a MMPRT on MRI. A retrospective review of the institutional database was performed for patients with an initial MRI diagnosis of a MMPRT. Patients were included if they had a subsequent follow-up MRI on the same knee. Patients with surgical intervention, including debridement or repair, were excluded. MRIs were evaluated by two board-certified musculoskeletal radiologists. MMPRTs were defined using the LaPrade classification, and the medial compartment articular cartilage was graded using the modified Outerbridge classification. MRIs were reviewed for meniscus extrusion, subchondral bone edema, and insufficiency fractures. Patients were divided into two groups for the analysis to account for differences in MRI time intervals. Group 1 had a follow-up MRI within 12 months of initial imaging (subacute group) and Group 2 had a follow-up MRI greater than 12 months after initial imaging (chronic group). Forty-one knees and 82 MRIs were analyzed, including 20 knees/40 MRIs (13 females, 7 males) in the subacute group and 21 knees/42 MRIs (14 females, 7 males) in the chronic group. Subacute patients had a mean age of 59.5 ± 8.8 years and a mean interval of 4.8 ± 2.6 months between MRIs compared with 53.6 ± 11.0 years and 38.2 ± 20.8 months, respectively, for the chronic group. Meniscal extrusion, femoral modified Outerbridge grade, and tibial modified Outerbridge grade worsened between initial and final MRI in both groups (p < 0.05). In both groups, there were no significant differences between initial and final MRIs with regard to the LaPrade classification, insufficiency fracture, or subchondral cysts of the tibia. Progressive meniscus extrusion and medial compartment articular cartilage degeneration were seen in patients with MMPRTs within a year from diagnosis.
Transketolase Activity but not Thiamine Membrane Transport Change in Response to Hyperglycaemia and Kidney Dysfunction
Authors: Chalásová Katarína , Pácal Lukáš , Pleskačová Anna , Knopfová Lucia , Řehořová Jitka , Tomandlová Marie , Tomandl Josef , Kaňková Kateřina
Published: September 2017

Aim Pentose phosphate pathway (PPP) with key enzyme transketolase (TKT), represents a potentially ‘protective’ mechanism in hyperglycaemia. Diabetic kidney disease (DKD), a common complication of both type 1 and type 2 diabetes associated with significant morbidity and mortality, represents the most common cause of chronic kidney disease (CKD). We hypothesized that protective PPP action in diabetes and eventually even more severely in concomitant DKD might be compromised by limited intracellular availability of an active TKT cofactor thiamine diphosphate (TDP).

Methods Effect of hyperglycaemia on gene expression and protein levels of key PPP loci was studied in vitro using human cell lines relevant to diabetes (HUVEC and HRGEC) and (together with measurement of TKT activity, plasma thiamine and erythrocyte TDP concentration) in vivo in diabetic vs. non-diabetic subjects with comparable renal function (n=83 in total).

Results Hyperglycaemia significantly decreased protein levels of RFC-1, THTR1, THTR2 and TKT (P<0.05) in vitro. Analysis of blood samples from CKD patients with and without diabetes and from controls did not reveal any difference in gene expression and protein levels of thiamine transporters while TKT activity and TDP in erythrocytes gradually increased with decreasing kidney function being highest in patients with CKD3-4 of both diabetic and non-diabetic aetiology. Hyperglycaemia and uremic serum mimicking CKD in diabetes did not affect TKT activity in vitro (P<0.05).

Conclusion Both in vitro and human experiments showed decrease or unchanged expression, respectively, of thiamine transporters induced by hyperglycaemia while TKT activity in parallel with intracellular TDP was increased in CKD patients with or without diabetes. Therefore, lack of adaptive increase of thiamine transmembrane transport allowing further increase of TKT activity might contribute to compromised PPP function in diabetes and CKD and to the development of glycotoxic injury.
Effects of HRV-Guided vs. Predetermined Block Training on Performance, HRV and Serum Hormones
Authors: Nuuttila Olli-Pekka , Nikander Aku , Polomoshnov Dmitry , Laukkanen Jari , Häkkinen Keijo
Published: September 2017

The aim of this study was to compare heart rate variability -guided (HRVG) and predetermined (PD) block periodization of high intensity aerobic training (HIT). Endurance performance, neuromuscular performance, heart rate variability (HRV) and serum hormone concentrations were measured before, in the middle and after the 8-week training period in 24 endurance trained males. Both groups improved significantly maximal treadmill velocity (Vmax) (p<0.001) and 3000 m running performance (HRVG; p<0.001 and PD; p=0.001). The relative changes in Vmax and countermovement jump were significantly greater in HRVG (p<0.05). Nocturnal heart rate decreased in both groups (p<0.01), but HRV (RMSSD, LF and TP) increased significantly only in HRVG (p<0.05). The significant increase in serum testosterone concentration was observed from mid to post in HRVG (p<0.05). Significant correlations were found between individual Vmax changes and absolute serum testosterone levels. Individual baseline level of HF correlated significantly with Vmax changes in PD. Block periodization of HIT seems to be an effective way to improve endurance and running performance in already endurance trained males. Based on training induced increases in endurance and neuromuscular performance combined with significant changes in HRV and serum testosterone levels observed in HRVG, individually HRV -guided block training may be more optimal compared to predetermined training.
Standardized MET Value Underestimates the Energy Cost of Treadmill Running in Men
Authors: Ázara Helouane , Farinatti Paulo , Midgley Adrian , Vasconcellos Fabrício , Vigário Patrícia , Cunha Felipe
Published: September 2017

The main purpose of the present study was to compare the reference metabolic equivalent (MET) value and observed resting oxygen uptake (VO2) for defining cardiorespiratory fitness (VO2max) and characterizing the energy cost of treadmill running. A heterogeneous cohort of 114 healthy men volunteered to participate. In Part 1 of the study, 114 men [mean±SD, age: 24±5 years; height: 177.1±7.9 cm; body mass: 75.0±10.0 kg] visited the laboratory twice for assessment of resting and maximal VO2 values to compare the reference MET value vs. observed resting VO2 and to investigate the association between resting VO2 and VO2max. In Part 2, 14 of the 114 men visited the laboratory once more to perform a 30-min bout of running at 8.0 km∙h−1/8.3 METs. The mean observed resting VO2 of 3.26 mL·kg−1·min−1 was lower than the reference MET value of 3.5 mL·kg−1·min−1 (P<0.001). Resting and maximal VO2 values relative to total body mass and fat-free mass were positively correlated (R=0.71 and 0.60, respectively; P<0.001). The maximal MET and energy cost of treadmill running were consequently underestimated when calculated using the reference MET value only for those with low VO2max (P=0.005 to P<0.001). In conclusion, the reference MET value considerably overestimated observed resting VO2 in men with low VO2max, resulting in underestimations of the maximal MET, exercise intensity prescription, and the energy cost of running.
Sphingosine kinase-2 Inhibitor ABC294640 Enhances Doxorubicin-Induced
Apoptosis of NSCLC Cells via Altering Survivin Expression
Authors: Hasanifard Leili , Samadi Nasser , Rashtchizadeh Nadereh , Dastmalchi Siavoush , Karimi Pouran
Published: September 2017

Background There is an urgent need to improve efficacy of
chemotherapeutics to overcome resistance in cancer treatment. Sphingosine
kinase-2 (SphK2) a key regulator of sphingolipid signaling has been
rationalized as an important therapeutic target. We evaluated the role of
SphK2 in doxorubicin (DOX)-induced apoptosis of NSCLC cells via altering
c-FLIPS, MCL-1 and survivin expressions in order to overcome
chemoresistance.

Methods Proliferation and apoptosis were evaluated by MTT assay and
DAPI staining, respectively. Cell population in each phase of cell cycle was
determined by flow cytometric assay. Gene and protein expression levels were
examined by quantitative RT-PCR and western blot analysis, respectively.

Results Phorbol myristate acetate (PMA), a SphK2 stimulator,
decreased cell death induced by IC50 of DOX (1.1 µM) to around
70% (p<0.01). Cell cycle analysis revealed a significant accumulation of
the cells in S phase with a marked decrease in sub G1 phase when we
incubated the cells with combined treatment of PMA and DOX (p<0.05).
Adding ABC294640 (40 µM), a SphK2 inhibitor, significantly abolished PMA
effect on cell survival (p<0.01). Survivin expression was significantly
diminished by applying ABC294640 either alone or in DOX treated cells
followed by increase in cell death (p<0.05), however, there was no
significant change in MCL-1 expression by ABC294640 either alone or in DOX
treated cells (p=0.16) and (p=0.06), respectively.

Conclusion Identifying cancer patients with high SphK2 expression and
then inhibiting of SphK2 activity can be considered as an important strategy
to increase the efficacy of DOX in the induction of apoptosis.
Drink and Think: Impact of Alcohol on Cognitive Functions and Dementia – Evidence of Dose-Related Effects
Authors: Gutwinski Stefan , Schreiter Stefanie , Priller Josef , Henssler Jonathan , Wiers Corinde , Heinz Andreas
Published: September 2017

Regular alcohol consumption affects cognitive performance and the development of dementia. So far, findings are contradicting, which might be explained in part by dose-related effects. For this narrative review, we undertook a literature search for surveys investigating the impact of alcohol consumption on cognitive performance and the development of dementia. The majority of studies observed a U-shaped relationship between regular alcohol consumption and cognitive function: frequent heavy consumption of alcohol alters brain functions and decreases cognitive performance; regular light and moderate consumption may have protective impact. In many studies, total abstainers show an inferior cognitive performance than people with moderate or light consumption. Nevertheless, policy implications are difficult to draw for at least 2 reasons: (1) the possible risks associated with alcohol consumption and (2) the potential confounders in the group of non-consumers and heavy consumers.
Electrical model of cold atmospheric plasma gun
Authors: Slutsker Ya. Z. , Semenov V. E. , Krasik Ya. E. , Ryzhkov M. A. , Felsteiner J. , Binenbaum Y. , Gil Z. , Shtrichman R. , Cohen J. T.
Published: September 2017

We present an analytical model of cold atmospheric plasma formed by a dielectric barrier discharge (DBD), which is based on the lumped and distributed elements of an equivalent electric circuit of this plasma. This model is applicable for a wide range of frequencies and amplitudes of the applied voltage pulses, no matter whether or not the generated plasma plume interacts with a target. The model allows quantitative estimation of the plasma plume length and the energy delivered to the plasma. Also, the results of this model can be used for the design of DBD guns which efficiently generate cold atmospheric plasma. A comparison of the results of the model with those obtained in experiments shows a fairly good agreement.
Influence of adsorbates on the performance of a field emitter array in a high voltage triode setup
Authors: Edler Simon , Bachmann Michael , Breuer Janis , Dams Florian , Düsberg Felix , Hofmann Martin , Jakšič Jasna , Pahlke Andreas , Langer Christoph , Ławrowski Robert , Prommesberger Christian , Schreiner Rupert
Published: September 2017

In the present work, black-silicon field emitter arrays (FEAs) are investigated regarding the influence of residual gas pressure on the characteristics and lifetime in the high voltage triode setup. Current-voltage-characteristics at different pressure levels are recorded and show a decreasing emission current with rising pressure. This decrease can be explained by an increase of the work function and charging of the emitter surface caused by adsorbates. The emission current can be restored to its initial value by heating of the FEA up to 110 °C during active emission. With this regeneration procedure, an extended lifetime from about 20 h to 440 h at a residual gas pressure of 10−5 mbar is achieved.
Breakthrough in current-in-plane tunneling measurement precision by application of multi-variable fitting algorithm
Authors: Cagliani Alberto , Østerberg Frederik W. , Hansen Ole , Shiv Lior , Nielsen Peter F. , Petersen Dirch H.
Published: September 2017

We present a breakthrough in micro-four-point probe (M4PP) metrology to substantially improve precision of transmission line (transfer length) type measurements by application of advanced electrode position correction. In particular, we demonstrate this methodology for the M4PP current-in-plane tunneling (CIPT) technique. The CIPT method has been a crucial tool in the development of magnetic tunnel junction (MTJ) stacks suitable for magnetic random-access memories for more than a decade. On two MTJ stacks, the measurement precision of resistance-area product and tunneling magnetoresistance was improved by up to a factor of 3.5 and the measurement reproducibility by up to a factor of 17, thanks to our improved position correction technique.
Enhanced stress-invariance of magnetization direction in magnetic thin films
Authors: Qiao Xinyu , Wen Xingcheng , Wang Baomin , Bai Yuhao , Zhan Qingfeng , Xu Xiaohong , Li Run-Wei
Published: September 2017

Spin valve devices, consisting of a free magnetic layer, a spacer layer, and a pinned magnetic layer, are widely used in magnetic sensors and nonvolatile magnetic memories. However, even a slight bending deformation can affect the magnetization direction of the free magnetic layer, which will change the magnetoresistance signal of the devices. Therefore, it is a challenge to develop a flexible spin valve device with controllable performance. Here, an enhanced stress-invariance of the magnetization direction in amorphous CoFeB magnetic films on flexible polyimide substrates is achieved. The uniaxial anisotropy is induced by growing on the bent substrate under a magnetic field, which aligns more magnetic domains with easy axes along the direction perpendicular to the subsequently applied stress. Theoretical calculations indicate that pre-induced anisotropy with an easy axis perpendicular to the applied stress effectively resists the change in the magnetization direction during bending. These results are of importance for realizing better performance of flexible spin valve devices and the development of flexible spintronics.
A stimulated emission study of the ground state bending levels of BH2 through the barrier to linearity and ab initio calculations of near-spectroscopic accuracy
Authors: Jin Bing , Clouthier Dennis J. , Tarroni Riccardo
Published: September 2017

The ground state bending levels of 11BH2 have been studied experimentally using a combination of low-resolution emission spectroscopy and high-resolution stimulated emission pumping (SEP) measurements. The data encompass the energy range below, through, and above the calculated position of the barrier to linearity. For the bending levels (0,3,0) and above, the data show substantial K-reordering, with the Ka″ = 1 levels falling well below those with Ka″ = 0. A comparison of the high-resolution rotationally resolved SEP data to our own very high level ab initio calculations of the rovibronic energy levels shows agreement approaching near-spectroscopic accuracy (a few cm−1). The data reported in this work provide very stringent tests for future theoretical treatments of this prototypical seven-electron free radical.
Contactless measurement of electrical conductivity for bulk nanostructured silver prepared by high-pressure torsion: A study of the dissipation process of giant strain
Authors: Mito Masaki , Shibayama Keisuke , Deguchi Hiroyuki , Tsuruta Kazuki , Tajiri Takayuki , Edalati Kaveh , Horita Zenji
Published: September 2017

We measured the electrical conductivity of bulk nanostructured silver prepared by high-pressure torsion (HPT) in a contactless manner by observing the AC magnetic susceptibility resulting from the eddy current, so that we could quantitatively analyze the dissipation process of the residual strain with sufficient time resolution as a function of temperature T and initial shear strain γ. The HPT process was performed at room temperature under a pressure of 6 GPa for revolutions N = 0–5, and we targeted a wide range of residual shear strains. The contactless measurement without electrode preparation enabled us to investigate both the fast and slow dissipation processes of the residual strain with sufficient time resolution, so that a systematic study of these processes became possible. The changes in the electrical conductivity as a function of N at room temperature were indeed consistent with changes in the Vickers microhardness; furthermore, they were also related to changes in structural parameters such as the preferred orientation, the interplanar distance, and the crystallite size. The dissipation process at N = 1, corresponding to γ ≈ 30, was the largest and the fastest. For N = 5, corresponding to γ ≈ 140, we considered the effects of grain boundaries, as well as those of dislocations. The strain dissipation was quite slow below T = 290 K. According to the analytical results, it became successful to conduct the quantitative evaluation of the strain dissipation at arbitrary temperatures: For instance, the relaxation times at T = 280 and 260 K were estimated to be 3.6 and 37 days, respectively.
Negative force on free carriers in positive index nanoparticles
Authors: Rahaman Mohammad Habibur , Kemp Brandon A.
Published: September 2017

We theoretically demonstrate the reversal of optical forces on free charge carriers in positive refractive index nanostructures. Though optical momentum in positive refractive index materials is necessarily parallel to the local energy flow, reversal of optical momentum transfer can be accomplished by exploiting the geometry and size of subwavelength particles. Using the Mie scattering theory and separation of optical momentum transfers to the bound and free charges and currents, we have shown that metal nanoparticles can exhibit strong momentum transfer to free carriers opposite to the direction of incident electromagnetic waves. This can be explained for small particles in terms of a reversal of Poynting power inside the material resulting in a negative net force on free carriers in small particles. Two-dimensional simulations further illuminate this point by demonstrating the effect of incident wave polarization.
Stochastic coupled cluster theory: Efficient sampling of the coupled cluster expansion
Authors: Scott Charles J. C. , Thom Alex J. W.
Published: September 2017

We consider the sampling of the coupled cluster expansion within stochastic coupled cluster theory. Observing the limitations of previous approaches due to the inherently non-linear behavior of a coupled cluster wavefunction representation, we propose new approaches based on an intuitive, well-defined condition for sampling weights and on sampling the expansion in cluster operators of different excitation levels. We term these modifications even and truncated selections, respectively. Utilising both approaches demonstrates dramatically improved calculation stability as well as reduced computational and memory costs. These modifications are particularly effective at higher truncation levels owing to the large number of terms within the cluster expansion that can be neglected, as demonstrated by the reduction of the number of terms to be sampled when truncating at triple excitations by 77% and hextuple excitations by 98%.
Enhancement of the spin-orbit torque in a Pt/Co system with a naturally oxidized Co layer
Authors: Hibino Y. , Hirai T. , Hasegawa K. , Koyama T. , Chiba D.
Published: September 2017

We investigated the effect of surface oxidation of a ferromagnetic Co layer on current-induced spin-orbit torque. A Co thin film was deposited on a Pt underlayer, for which the spin current was expected to be generated through the spin Hall effect. Both the damping- and field-like torques quantitatively determined using harmonic Hall voltage measurements were clearly enhanced in the sample with the naturally oxidized Co layer. Even though the oxidized system possessed a larger perpendicular magnetic anisotropy and nearly the same areal magnetization value, i.e., the same effective ferromagnetic thickness, as those of the unoxidized sample, the electrical current required for magnetization switching was greatly reduced. The results clearly show that surface oxidization of a ferromagnetic thin film deposited on a heavy metal layer plays an important role in enlarging spin-orbit torque.
Defect induced polarization and dielectric relaxation in Ga2–xFexO3
Authors: Mahana Sudipta , Dhanasekhar C. , Venimadhav A. , Topwal D.
Published: September 2017

We report dielectric and pyroelectric responses of solid solutions of Ga2–xFexO3 (x = 0.75, 1.0, and 1.25), exhibiting combined relaxations (Maxwell-Wagner type relaxation and Debye relaxation); however, the dominating contribution is found to be from extrinsic Maxwell-Wagner type relaxation. Furthermore, the emergence of polarization in these systems is understood in terms of the thermally stimulated depolarization current effect caused by freezing of defect dipoles associated with charged oxygen vacancies rather than the intrinsic ferroelectric behavior.
Promising ferroelectricity in 2D group IV tellurides: a first-principles study
Authors: Wan Wenhui , Liu Chang , Xiao Wende , Yao Yugui
Published: September 2017

Based on the first-principles calculations, we investigated the ferroelectric properties of two-dimensional (2D) Group-IV tellurides XTe (X = Si, Ge, and Sn), with a focus on GeTe. 2D Group-IV tellurides energetically prefer an orthorhombic phase with a hinge-like structure and an in-plane spontaneous polarization. The intrinsic Curie temperature Tc of monolayer GeTe is as high as 570 K and can be raised quickly by applying a tensile strain. An out-of-plane electric field can effectively decrease the coercive field for the reversal of polarization, extending its potential for regulating the polarization switching kinetics. Moreover, for bilayer GeTe, the ferroelectric phase is still the ground state. Combined with these advantages, 2D GeTe is a promising candidate material for practical integrated ferroelectric applications.
Deviations from Vegard's law in semiconductor thin films measured with X-ray diffraction and Rutherford backscattering: The Ge1-ySny and Ge1-xSix cases
Authors: Xu Chi , Senaratne Charutha L. , Culbertson Robert J. , Kouvetakis John , Menéndez José
Published: September 2017

The compositional dependence of the lattice parameter in Ge1-ySny alloys has been determined from combined X-ray diffraction and Rutherford Backscattering (RBS) measurements of a large set of epitaxial films with compositions in the 0 < y < 0.14 range. In view of contradictory prior results, a critical analysis of this method has been carried out, with emphasis on nonlinear elasticity corrections and systematic errors in popular RBS simulation codes. The approach followed is validated by showing that measurements of Ge1-xSix films yield a bowing parameter θGeSi =−0.0253(30) Å, in excellent agreement with the classic work by Dismukes. When the same methodology is applied to Ge1-ySny alloy films, it is found that the bowing parameter θGeSn is zero within experimental error, so that the system follows Vegard's law. This is in qualitative agreement with ab initio theory, but the value of the experimental bowing parameter is significantly smaller than the theoretical prediction. Possible reasons for this discrepancy are discussed in detail.
Taylor problem and onset of plasmoid instability in the Hall-magnetohydrodynamics
Authors: Vekstein G. , Kusano K.
Published: September 2017

A well-known Taylor problem in the theory of forced magnetic reconnection is investigated in the framework of the Hall-Magnetohydrodynamics. In the first part of the paper, we deal with the linear theory of the Hall-mediated forced reconnection. Then, in the second part, these results are used for demonstrating how the secondary tearing (plasmoid) instability can develop in the course of this process.
Effect of room temperature lattice vibration on the electron transport in graphene nanoribbons
Authors: Liu Yue-Yang , Li Bo-Lin , Chen Shi-Zhang , Jiang Xiangwei , Chen Ke-Qiu
Published: September 2017

We observe directly the lattice vibration and its multifold effect on electron transport in zigzag graphene nanoribbons in simulation by utilizing an efficient combined method. The results show that the electron transport fluctuates greatly due to the incessant lattice vibration of the nanoribbons. More interestingly, the lattice vibration behaves like a double-edged sword that it boosts the conductance of symmetric zigzag nanoribbons (containing an even number of zigzag chains along the width direction) while weakens the conductance of asymmetric nanoribbons. As a result, the reported large disparity between the conductances of the two kinds of nanoribbons at 0 K is in fact much smaller at room temperature (300 K). We also find that the spin filter effect that exists in perfect two-dimensional symmetric zigzag graphene nanoribbons is destroyed to some extent by lattice vibrations. Since lattice vibrations or phonons are usually inevitable in experiments, the research is very meaningful for revealing the important role of lattice vibrations play in the electron transport properties of two-dimensional materials and guiding the application of ZGNRs in reality.
Dynamic frequency-constrained unit commitment in isolated grids with DFIGs for frequency regulation
Authors: Lin Tao , Ye Jing , Li Shichun , Zhang Lei , Xu Xialing , Chen Rusi
Published: September 2017

The use of doubly fed induction generators (DFIGs) in isolated grids (IGs) deteriorates system inertial and primary frequency regulation ability. In this paper, integrating DFIGs in the inertial response is used to maintain the frequency dynamic security. The rate of change of frequency (RoCoF) and frequency nadir expression after contingence are derived by encapsulating the DFIGs' inertial response. Due to the time variation of the inertial response of DFIGs, a method based on curve fitting is derived to calculate the frequency nadir. A Unit Commitment (UC) model with dynamic frequency constraints is established accordingly. The model represents a complex nonlinear mixed integer optimization problem. Then, the model is decomposed into a master problem for conventional UC with the RoCoF constraint which is a mixed-integer linear programming problem and a sub-problem for frequency verification. The so-called optimization cuts are generated to eliminate the frequency limitation in the iteration method. An isolated grid (IG) test system is utilized to demonstrate that the proposed method ensures system frequency security while retaining favorable economic performance.
Advances in the two-dimensional structural detail of plasma turbulence in a tokamak
Authors: Cockbill Louisa
Published: September 2017

Researchers capture cross-correlation functions of turbulence at the plasma edge in the NSTX tokamak.
Post-arc current simulation based on measurement in vacuum circuit breaker with a one-dimensional particle-in-cell model
Authors: Jia Shenli , Mo Yongpeng , Shi Zongqian , Li Junliang , Wang Lijun
Published: September 2017

The post-arc dielectric recovery process has a decisive effect on the current interruption performance in a vacuum circuit breaker. The dissipation of residual plasma at the moment of current zero under the transient recovery voltage, which is the first stage of the post-arc dielectric recovery process and forms the post-arc current, has attracted many concerns. A one-dimensional particle-in-cell model is developed to simulate the measured post-arc current in the vacuum circuit breaker in this paper. At first, the parameters of the residual plasma are estimated roughly by the waveform of the post-arc current which is taken from measurements. After that, different components of the post-arc current, which are formed by the movement of charged particles in the residual plasma, are discussed. Then, the residual plasma density is adjusted according to the proportion of electrons and ions absorbed by the post-arc anode derived from the particle-in-cell simulation. After this adjustment, the post-arc current waveform obtained from the simulation is closer to that obtained from measurements.
Filament characterization via resonance absorption of terahertz wave
Authors: Zheng Zhigang , Huang Yindong , Guo Quan , Meng Chao , Lü Zhihui , Wang Xiaowei , Zhao Jing , Meng Congsen , Zhang Dongwen , Yuan Jianmin , Zhao Zengxiu
Published: September 2017

In this work, we characterize the transmission properties of the focusing-laser-induced filament by using terahertz (THz) time domain spectroscopy. Significant resonance absorption of the THz wave is identified, which is attributed to the dynamic screening of the ionized electrons. The polarization and intensity of the filament-generated pulse have been varied to study their influences on the resonance absorption. Our results suggest that the electron density of the filament can be determined by fitting the phase shifts and absorption properties around the absorption. This method provides not only an alternative to the plasma diagnostics with plasma frequency at the THz range, but also a supplement to the existing generation theory of THz waves from plasma.
Noise induced regularity of porous silicon nanostructures electrochemically etched in the presence of a sub-threshold periodic signal
Authors: Roy Tanushree , Rumandla Sravya , Agarwal V. , Parmananda P.
Published: September 2017

In the present work, regularity of the pores generated during the electrochemical etching of silicon wafer is analyzed. The wafer-electrolyte (ethanolic hydrofluoric acid) composite is placed in an electrochemical cell operated galvanostatically at a fixed (set-point) anodic current. This set-point current is subsequently perturbed by a sub-threshold periodic current signal. Numerous experiments were performed for diverse experimental configurations. Some of the experimental parameters varied were hydrofluoric concentration, set-points, and the properties of the input periodic signal (i.e., duty cycle and amplitude). The regularity of the generated pore size distribution was quantified by calculating the spatial normalized variance (NV). For certain experimental configurations, as described later, the phenomena of Periodic Stochastic Resonance (PSR) could be provoked. In PSR, enhanced regularity of the Porous Silicon nanostructures for an optimal HF concentration is observed. Consequently, the spatial NV versus the HF concentration curve exhibits a unimodal profile.
Advanced electron transfer-induced heat transport theory that considers vibrational heat transfer
Authors: Hendricks-Sturrup Rachele
Published: September 2017

Theoretical chemists offer novel theory on transfer-induced heat transport and vibrational heat transfer during electron transfer.
Zonal flows driven by the turbulent energy flux and the turbulent toroidal Reynolds stress in a magnetic fusion torus
Authors: Wang Shaojie
Published: September 2017

It is shown that zonal flows can be driven by the turbulent energy flux and the turbulent toroidal Reynolds stress in a tokamak plasma. The proposed theory may resolve the controversial issues on the Limit-Cycle-Oscillation dynamics raised by the recent tokamak L-H transition experiments.
Exploiting spatial degrees of freedom for high data rate ultrasound communication with implantable devices
Authors: Wang Max L. , Arbabian Amin
Published: September 2017

We propose and demonstrate an ultrasonic communication link using spatial degrees of freedom to increase data rates for deeply implantable medical devices. Low attenuation and millimeter wavelengths make ultrasound an ideal communication medium for miniaturized low-power implants. While a small spectral bandwidth has drastically limited achievable data rates in conventional ultrasonic implants, a large spatial bandwidth can be exploited by using multiple transducers in a multiple-input/multiple-output system to provide spatial multiplexing gain without additional power, larger bandwidth, or complicated packaging. We experimentally verify the communication link in mineral oil with a transmitter and a receiver 5 cm apart, each housing two custom-designed mm-sized piezoelectric transducers operating at the same frequency. Two streams of data modulated with quadrature phase-shift keying at 125 kbps are simultaneously transmitted and received on both channels, effectively doubling the data rate to 250 kbps with a measured bit error rate below 10−4. We also evaluate the performance and robustness of the channel separation network by testing the communication link after introducing position offsets. These results demonstrate the potential of spatial multiplexing to enable more complex implant applications requiring higher data rates.
Researchers observe detailed structure of a model interface for a rechargeable battery
Authors: Kim Meeri
Published: September 2017

Japanese scientists use frequency-modulation atomic force microscopy to study the tetraglyme-graphite interface.
I–V curve hysteresis induced by gate-free charging of GaAs nanowires' surface oxide
Authors: Alekseev P. A. , Geydt P. , Dunaevskiy M. S. , Lähderanta E. , Haggrén T. , Kakko J.-P. , Lipsanen H.
Published: September 2017

The control of nanowire-based device performance requires knowledge about the transport of charge carriers and its limiting factors. We present the experimental and modeled results of a study of electrical properties of GaAs nanowires (NWs), considering their native oxide cover. Measurements of individual vertical NWs were performed by conductive atomic force microscopy (C-AFM). Experimental C-AFM observations with numerical simulations revealed the complex resistive behavior of NWs. A hysteresis of current-voltage characteristics of the p-doped NWs as-grown on substrates with different types of doping was registered. The emergence of hysteresis was explained by the trapping of majority carriers in the surface oxide layer near the reverse-biased barriers under the source-drain current. It was found that the accumulation of charge increases the current for highly doped p+-NWs on n+-substrates, while for moderately doped p-NWs on p+-substrates, charge accumulation decreases the current due to blocking of the conductive channel of NWs.
Mammal conservation and invasive species control in Australia: harnessing a potential extinction machine
Authors: Kinnear J. E.
Published: September 2017

The catastrophic declines and extinctions of a unique Gondwana-derived Australian mammalian fauna is a wildlife tragedy of epic proportions that remains to be played out. Four alien species in particular, rabbits (Oryctolagus cuniculus), foxes (Vulpes vulpes), feral cats (Felis catus) and cane toads (Rhinella marina) are recognised as ongoing threats, but protective control protocols consist of holding actions that currently require never-ending ecosystem subsidies (typically, culling and fencing). Recent revolutionary developments in cell biology and gene engineering – the CRISPR invention – has enabled the construction of gene drives that offer the prospect of controlling these species more efficiently indeed, even the possibility of extirpating these species from Australia. The conservation potential of these new technologies is described and recommendations are made.