bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of fluorescence quenching due to 2, 3, 5, 6-tetrafluoro-7, 7′, 8, 8′-tetracyano quinodimethane and its solid state diffusion analysis using photoluminescence spectroscopy
Authors: Tyagi Priyanka , Tuli Suneet , Srivastava Ritu
Published: February 2015

In this work, we have studied the fluorescence quenching and solid state diffusion of 2, 3, 5, 6-tetrafluoro-7,  7′,  8,  8′-tetracyano quinodimethane (F4-TCNQ) using photoluminescence (PL) spectroscopy. Quenching studies were performed with tris (8-hydroxyquinolinato) aluminum (Alq3) in solid state samples. Thickness of F4-TCNQ was varied in order to realize different concentrations and study the effect of concentration. PL intensity has reduced with the increase in F4-TCNQ thicknesses. Stern-Volmer and bimolecular quenching constants were evaluated to be 13.8 M−1 and 8.7 × 108 M−1 s−1, respectively. The quenching mechanism was found to be of static type, which was inferred by the independent nature of excited state life time from the F4-TCNQ thickness. Further, solid state diffusion of F4-TCNQ was studied by placing a spacing layer of α-NPD between F4-TCNQ and Alq3, and its thickness was varied to probe the diffusion length. PL intensity was found to increase with the increase in this thickness. Quenching efficiency was evaluated as a function of distance between F4-TCNQ and Alq3. These studies were performed for the samples having 1, 2.5, and 5.5 nm thicknesses of F4-TCNQ to study the thickness dependence of diffusion length. Diffusion lengths were evaluated to be 12.5, 15, and 20 nm for 1, 2.5, and 5.5 nm thicknesses of F4-TCNQ. These diffusion lengths were found to be very close to that of determined by secondary ion mass spectroscopy technique.
The magnetic behavior of the intermetallic compound NdMn2Ge2 studied by magnetization and hyperfine interactions measurements
Authors: Bosch-Santos B. , Carbonari A. W. , Cabrera-Pasca G. A. , Saxena R. N. , Freitas R. S.
Published: February 2015

The magnetic behavior of the intermetallic compound NdMn2Ge2 was investigated by bulk magnetization measurements and measurements of hyperfine interactions using perturbed γ–γ angular correlation (PAC) spectroscopy. Magnetization measurements indicate the presence of four magnetic transitions associated with the Mn and Nd magnetic sublattices. At high temperatures, magnetic measurements show a change in the slope of the magnetization due to an antiferromagnetic transition around TN ∼ 425 K and a well defined ferromagnetic transition at TC ∼ 320 K. Moreover, at ∼210 K a peak is observed in the magnetization curve, which is assigned to the reorientation of the Mn spin, and at ∼25 K an increase in the magnetic moment is also observed, which is ascribed to the ordering of Nd ions. PAC measurements using 140La(140Ce) and 111In(111Cd) probe nuclei allowed the determination of the temperature dependence of the magnetic hyperfine field (Bhf) at Nd and Mn sites, respectively. PAC results with 111Cd probe nuclei at Mn sites show that the dependence of Bhf with temperature follows the expected behavior for the host magnetization associated with the magnetic ordering of Mn ions. From these results, the antiferromagnetic transition followed by a ferromagnetic ordering is clearly observed. PAC results with 140Ce probe nuclei at Nd sites, however, showed a strong deviation from the Brillouin function, which is attributed to the Ce 4f-electron contribution to Bhf.
In situ measurement of increased ferroelectric/ferroelastic domain wall motion in declamped tetragonal lead zirconate titanate thin films
Authors: Wallace M. , Johnson-Wilke R. L. , Esteves G. , Fancher C. M. , Wilke R. H. T. , Jones J. L. , Trolier-McKinstry S.
Published: February 2015

Ferroelectric/ferroelastic domain reorientation was measured in a 1.9 μm thick tetragonal {001} oriented PbZr0.3Ti0.7O3 thin film doped with 1% Mn under different mechanical boundary constraints. Domain reorientation was quantified through the intensity changes in the 002/200 Bragg reflections as a function of applied electric field. To alter the degree of clamping, films were undercut from the underlying substrate by 0%, ∼25%, ∼50%, or ∼75% of the electrode area. As the amount of declamping from the substrate increased from 0% to ∼75%, the degree of ferroelectric/ferroelastic domain reorientation in the films increased more than six fold at three times the coercive field. In a film that was ∼75% released from the substrate, approximately 26% of 90° domains were reoriented under the maximum applied field; this value for domain reorientation compares favorably to bulk ceramics of similar compositions. An estimate for the upper limit of 90° domain reorientation in a fully released film under these conditions was determined to be 32%. It was also found that the different clamping conditions strongly influence the amount of reorientation upon removing the applied field, with higher remanence of preferred domain orientations observed in declamped films.
Light extraction analysis of organic light emitting diodes fabricated on high refractive index glass scattering layer
Authors: Nakamura N. , Fukumoto N. , Wada N. , Ohgawara M.
Published: February 2015

Optical analysis was performed for Organic Light Emitting Diodes (OLEDs) formed on a high refractive index glass (high-n-glass) scattering layer. Angular dependency of luminance for OLEDs fabricated on high-n-glass substrate with a hemisphere high-n-glass lens has a good agreement with the emitting directivity calculated by an interference simulation. Applying this emitting directivity, ray trace simulation was performed for OLEDs on various types of substrates and hemisphere lenses. The calculated out-coupled light flux has a good agreement with the measured values. From the experimental and simulation results, it can be concluded that out-coupling efficiency is 1.7 times compared to the reference, and about 55% of lights out of the OLED device can be extracted to the air by the high-n-glass scattering layer. In this case, the probability of light out-coupling as a function of emitting angle starts at 66% at 0°, and still remains more than 30% up to 70° from the normal direction.
Vertical bearing behaviour of the composite bucket shallow foundation of offshore wind turbines
Authors: Liu Run , Chen Guangsi , Lian Jijian , Ding Hongyan
Published: February 2015

A composite bucket shallow foundation (CBSF) has been proposed by Tianjin University to adapt the offshore soft geological conditions of China for wind turbines. Vertical bearing capacity modelling and observation tests regarding the CBSF are performed. The test results are accompanied by numerical simulations to provide a better understanding of the failure mechanism of the CBSF. The upper limit of the vertical bearing capacity of the bucket foundation is derived through the upper bound theorem of classical plasticity theory according to the failure mechanism. The soil damage rate is specified as a new empirical parameter in the formula and is defined as the rate between the thickness of the soil that is broken inside the foundation and the radius of the foundation, which indicates the range of soil failure. Furthermore, the range of the soil damage rate is obtained through vertical bearing capacity model tests. The relationship of the bearing capacity factor Nq and Nγ with the friction angle is also discussed under the specific soil damage rates.
Micro-focused Brillouin light scattering study of the magnetization dynamics driven by Spin Hall effect in a transversely magnetized NiFe nanowire
Authors: Madami M. , Gubbiotti G. , Moriyama T. , Tanaka K. , Siracusano G. , Carpentieri M. , Finocchio G. , Tacchi S. , Ono T. , Carlotti G.
Published: February 2015

We employed micro-focused Brillouin light scattering to study the amplification of the thermal spin wave eigenmodes by means of a pure spin current, generated by the spin-Hall effect, in a transversely magnetized Pt(4 nm)/NiFe(4 nm)/SiO2(5 nm) layered nanowire with lateral dimensions 500 × 2750 nm2. The frequency and the cross section of both the center (fundamental) and the edge spin wave modes have been measured as a function of the intensity of the injected dc electric current. The frequency of both modes exhibits a clear redshift while their cross section is greatly enhanced on increasing the intensity of the injected dc. A threshold-like behavior is observed for a value of the injected dc of 2.8 mA. Interestingly, an additional mode, localized in the central part of the nanowire, appears at higher frequency on increasing the intensity of the injected dc above the threshold value. Micromagnetic simulations were used to quantitatively reproduce the experimental results and to investigate the complex non-linear dynamics induced by the spin-Hall effect, including the modification of the spatial profile of the spin wave modes and the appearance of the extra mode above the threshold.
Tightly wrapped semiconductor-axon microtubes for probing hybrid networks: Modeling the capacitive coupling strength
Authors: Diedrich Daniel , Blick Robert H.
Published: February 2015

We present finite-element simulations modeling the electromagnetic interaction between axons and semiconductor microtubes. These tubes are tightly wrapped around the axons, enabling highly efficient capacitive coupling. The calculations reveal that the capacitive coupling strength is in the pA regime.
Fabrication and properties of ZnO nanorods within silicon nanostructures for solar cell application
Authors: Feng Zezeng , Jia Rui , Dou Bingfei , Li Haofeng , Jin Zhi , Liu Xinyu , Li Feng , Zhang Wei , Wu Chenyang
Published: February 2015

ZnO nanorods (NRs) were synthesized via a two-step hydrothermal method on silicon (Si) nano-textured solar cells. The optical and photovoltaic properties of silicon nanostructures coated with ZnO NRs were measured and discussed. It was found that silicon nanostructures combined with ZnO NRs can maximize the light absorption and significantly enhance the electrode contact and carrier transport ability. The series resistance was reduced from 0.98 Ω to 0.45 Ω, and short circuit current density was dramatically increased from 22.5 mA/cm2 to 27.9 mA/cm2 due to the incorporation of the ZnO NRs. The experimental results show the potential of ZnO NRs' application to the enhancement of the performance of nano-textured solar cells.
Step density model of laser sustained ion channel and Coulomb explosion
Authors: Rajouria Satish Kumar , Malik H. K. , Tripathi V. K. , Kumar Pawan
Published: February 2015

An analytical model of laser sustained ion channel in plasma is developed, assuming electron density to be zero in the inner region and constant outside. The radius of the channel is such that the ponderomotive force on electrons at the channel boundary is balanced by the channel space charge force. The laser is TM eigen mode of the system with Bessel function profile in the interior and modified Bessel function outside. The channel radius increases with laser intensity and the ratio of laser frequency to plasma frequency. Ion Coulomb explosion of the channel, on longer time scale, produces ion energy distribution, an increasing function of energy with a sharp cutoff equal to electron ponderomotive energy at the channel boundary. At peak laser intensity ≈2×1019W/cm2 at 1 μm wavelength and spot size of 8 μm, the cutoff ion energy in a plasma of density ∼1019cm−3 is ∼0.73 MeV.
Nonlinear dispersion and transverse profile of intense electromagnetic waves, propagating through electron-positron-ion hot magnetoplasma
Authors: Javan N. Sepehri , Homami S. H. H.
Published: February 2015

Self-guided nonlinear propagation of intense circularly-polarized electromagnetic waves in a hot electron-positron-ion magnetoplasma is studied. Using a relativistic fluid model, a nonlinear equation is derived, which describes the interaction of the electromagnetic wave with the plasma in the quasi-neutral approximation. Transverse Eigen modes, the nonlinear dispersion relation and the group velocity are obtained. Results show that the transverse profile in the case of magnetized plasma with cylindrical symmetry has a radially damping oscillatory form. Effect of applying external magnetic fields, existence of the electron-positron pairs, changing the amplitude of the electromagnetic wave, and its polarization on the nonlinear dispersion relation and Eigen modes are studied.
Statistical mechanics of dust charging in a multi-ion plasma with negative and positive ionic species
Authors: Mishra S. K. , Misra Shikha
Published: February 2015

On the basis of statistical mechanics and charging kinetics, the charge distribution over uniform size spherical dust particles in a multi-ion plasma comprising of multiple charged negative and positive ions is investigated. Two specific situations where the complex plasma is viz., (i) dark (no emission from dust) and (ii) irradiated by laser light (causing photoemission from dust) have been taken into account. The analytical formulation includes the population balance equation for the charged dust particles along with number and energy balance of the complex plasma constituents. The departure of the results for multi-ion plasma from that in case of usual singly charged positive ion plasma is graphically illustrated and discussed. In contrast to electron-ion plasma, significant number of particles is seen to acquire opposite charge in case of pure positive-negative ion plasma, even in the absence of electron emission from the dust grains. The effects of various plasma parameters viz., number density, particle size, and work function of dust on charge distribution have also been examined.
Development of Thomson scattering system on Shenguang-III prototype laser facility
Authors: Gong Tao , Li Zhichao , Jiang Xiaohua , Ding Yongkun , Yang Dong , Wang Zhebin , Wang Fang , Li Ping , Hu Guangyue , Zhao Bin , Liu Shenye , Jiang Shaoen , Zheng Jian
Published: February 2015

A Thomson scattering diagnostic system, using a 263 nm laser as the probe beam, is designed and implemented on Shenguang-III prototype laser facility. The probe beam is provided by an additional beam line completed recently. The diagnostic system allows simultaneous measurements of both ion feature and red-shifted electron feature from plasmas in a high-temperature (≥2 keV) and high-density (≥1021 cm−3) regime. Delicate design is made to satisfy the requirements for successful detection of the electron feature. High-quality ion feature spectra have already been diagnosed via this system in recent experiments with gas-filled hohlraums.
Plasmonic light trapping in an ultrathin photovoltaic layer with film-coupled metamaterial structures
Authors: Wang Hao , Wang Liping
Published: February 2015

A film-coupled metamaterial structure is numerically investigated for enhancing the light absorption in an ultrathin photovoltaic layer of crystalline gallium arsenide (GaAs). The top subwavelength concave grating and the bottom metallic film could not only effectively trap light with the help of wave interference and magnetic resonance effects excited above the bandgap, but also practically serve as electrical contacts for photon-generated charge collection. The energy absorbed by the active layer is greatly enhanced with the help of the film-coupled metamaterial structure, resulting in significant improvement on the short-circuit current density by three times over a free-standing GaAs layer at the same thickness. The performance of the proposed light trapping structure is demonstrated to be little affected by the grating ridge width considering the geometric tolerance during fabrication. The optical absorption at oblique incidences also shows direction-insensitive behavior, which is highly desired for efficiently converting off-normal sunlight to electricity. The results would facilitate the development of next-generation ultrathin solar cells with lower cost and higher efficiency.
Back-action-induced excitation of electrons in a silicon quantum dot with a single-electron transistor charge sensor
Authors: Horibe Kosuke , Kodera Tetsuo , Oda Shunri
Published: February 2015

Back-action in the readout of quantum bits is an area that requires a great deal of attention in electron spin based-quantum bit architecture. We report here back-action measurements in a silicon device with quantum dots and a single-electron transistor (SET) charge sensor. We observe the back-action-induced excitation of electrons from the ground state to an excited state in a quantum dot. Our measurements and theoretical fitting to the data reveal conditions under which both suitable SET charge sensor sensitivity for qubit readout and low back-action-induced transition rates (less than 1 kHz) can be achieved.
Limits on the bolometric response of graphene due to flicker noise
Authors: Grover Sameer , Dubey Sudipta , Mathew John P. , Deshmukh Mandar M.
Published: February 2015

We study the photoresponse of graphene field effect transistors using scanning photocurrent microscopy in near and far field configurations, and we find that the response of graphene under a source–drain bias voltage away from the contacts is dominated by the bolometric effect caused by laser induced heating. We find no significant change in the photocurrent with the optical modulation frequency upto 100 kHz. Although the magnitude of the bolometric current scales with bias voltage, it also results in noise. The frequency dependence of this noise indicates that it has a 1/f character, scales with the bias voltage, and limits the detectable bolometric photoresponse at low optical powers.
Optically transparent frequency selective surfaces on flexible thin plastic substrates
Authors: Dewani Aliya A. , O’Keefe Steven G. , Thiel David V. , Galehdar Amir
Published: February 2015

A novel 2D simple low cost frequency selective surface was screen printed on thin (0.21 mm), flexible transparent plastic substrate (relative permittivity 3.2). It was designed, fabricated and tested in the frequency range 10-20 GHz. The plane wave transmission and reflection coefficients agreed with numerical modelling. The effective permittivity and thickness of the backing sheet has a significant effect on the frequency characteristics. The stop band frequency reduced from 15GHz (no backing) to 12.5GHz with polycarbonate. The plastic substrate thickness beyond 1.8mm has minimal effect on the resonant frequency. While the inner element spacing controls the stop-band frequency, the substrate thickness controls the bandwidth. The screen printing technique provided a simple, low cost FSS fabrication method to produce flexible, conformal, optically transparent and bio-degradable FSS structures which can find their use in electromagnetic shielding and filtering applications in radomes, reflector antennas, beam splitters and polarizers.
Binging and purging: agrofood capitalism and the body as socioecological fix
Authors: Guthman Julie
Published: February 2015

Theorizations of the spatial fix classically look to geographical expansion as the fix for capitalism's perennial crises of overaccumulation. Recent scholarship, evident in this theme issue, extends this thinking to the socioecological, recognizing that many ‘fixes’ these days involve appropriating or reconfiguring nature anew. This paper extends this yet further, by considering the body as a site of socioecological fixes. In recognition of Harvey's original notion of the spatial fix being always in relation to limits, this theorization puts a finer point on scholarship on the body as an accumulation strategy which has not always acknowledged the dialectical elements of this strategy. The body as a site of both limits and fixes is traced through the case of food marketing and processing strategies designed to overcome the obstacle to capitalist accumulation enshrined in Engel's law. These have in part contributed to the so-called obesity epidemic; and they are also involved in the commodified cures designed to resolve it—metabolism-defying diet foods being the example par excellence. These are designed to overcome particular limits of accumulation but, in doing so, produce new problems that are only partially resolved. Although the examples provided in this paper are limited to obesity and its putative cures, the larger point is to shed light on capitalism's potential to significantly rework bodily processes and spaces in ways conducive to ongoing accumulation, as immanent in the bioeconomy.
Divergent foraging behaviour of a desert rodent, Notomys fuscus, in covered and open microhabitats revealed using giving up densities and video analysis
Authors: Morris Timothy , Gordon Christopher E. , Letnic Mike
Published: February 2015

We used a combination of giving up densities (GUD) and behavioural analysis from video footage to test the response of an Australian desert rodent, Notomys fuscus, to the experimental provision of cover microhabitat in the Strzelecki Desert, Australia. In many ecosystems, cover microhabitats are considered to be safe foraging locations for rodents. The response of bipedal desert rodents to cover microhabitats is less certain, with varied findings, due to their use of open habitats for fast travel. Notomys fuscus returned lower GUDs in cover than in open microhabitats and moved slowly for a greater amount of time under cover than in the open. These results suggest that N. fuscus has a preference for foraging under cover, where predation risk is lower, and under these conditions took longer to assess the cover microhabitat before foraging. This was distinctly different to the ‘get in, get out’ behaviour associated with foraging in open habitats. We advocate for the combined measurement of GUD and behavioural analysis using video footage as a way to improve understanding of rodents’ foraging behaviour.
Modelling and mapping rainfall erosivity in New South Wales, Australia
Authors: Yang Xihua , Yu Bofu
Published: February 2015

Considerable seasonal and inter-annual changes exist in rainfall amount and intensity in New South Wales (NSW), Australia. These changes are expected to have significant effect on rainfall erosivity and soil erosion by water, but the magnitude of the impact is not well quantified because of the non-linear and dynamic nature of the relationship between rainfall amount and rainfall erosivity. The primary aim of this study was to model spatial and temporal variations in rainfall erosivity and impacts on hillslope erosion across NSW. We developed a daily rainfall erosivity model for NSW to calculate monthly and annual rainfall erosivity values by using gridded daily rainfall data for a continuous 53-year period including a baseline period (1961–90) and a recent period (2000–12). Model parameters were improved based on their geographic locations and elevations to be truly geo-referenced and representative of the regional relationships. Monthly and annual hillslope erosion risk for the same periods was estimated with the Revised Universal Soil Loss Equation. We produced finer scale (100-m) maps of rainfall erosivity and hillslope erosion through spatial interpolation techniques, and implemented the calculation of rainfall erosivity and hillslope erosion in a geographic information system by using automated scripts so that it is fast, repeatable and portable. The modelled rainfall erosivity values were compared with pluviograph calculations and previous studies, and the Nash–Sutcliffe coefficient of efficiency is >0.90. Outcomes from this study provide not only baseline information but also continuous estimates of rainfall erosivity and hillslope erosions allowing better monitoring and mitigation of hillslope erosion risk in NSW.
Extracellular forms of IL-37 inhibit innate inflammation in vitro and in vivo but require the IL-1 family decoy receptor IL-1R8
Authors: Li Suzhao , Neff C. Preston , Barber Kristina , Hong Jaewoo , Luo Yuchun , Azam Tania , Palmer Brent E. , Fujita Mayumi , Garlanda Cecilia , Mantovani Alberto , Kim Soohyun , Dinarello Charles Anthony
Published: February 2015

Significance

Interleukin-1 family members are highly inflammatory but IL-37 member broadly suppresses inflammation and specific immunity. Initially, the mechanism of this suppression was shown to be via translocation to the nucleus following cleavage of the precursor by intracellular caspase-1. We now show that recombinant forms of IL-37 limit inflammation by extracellular binding to surface receptors but require the IL-1 family decoy receptor IL-1R8. Unexpectedly, picomolar concentrations of the IL-37 precursor optimally suppress IL-1β, IL-6, and TNFα production from human blood M1 macrophages, suggesting a unique function for a coreceptor function of IL-1R8. Assessment of IL-37 as well as IL-1R8 levels may provide previously unidentified insights into how the host limits inflammation.
CUBISM: Belief, anomaly and social constructs
Authors: Wilks Yorick , Clark Micah , By Tomas , Dalton Adam , Perera Ian
Published: February 2015

We introduce the CUBISM system for the analysis and deep understanding of multi-participant dialogues. CUBISM brings together two typically separate forms of discourse analysis: semantic analysis and sociolinguistic analysis. In the paper proper, we describe and illustrate major components of the CUBISM system, and discuss the challenge posed by the system’s ultimate purpose, which is to automatically detect anomalous changes in participants’ expressed or implied beliefs about the world and each other, including shifts toward or away from cultural and community norms.
Whatever happened to the Occitango-past?
Authors: Jacobs Bart , Kunert Hans Peter
Published: February 2015

This article explores the history and present state of the Occitango-past. Also known as theperfet perifràstic, this is a characteristic and well-studied feature of the Catalan grammar (vaig cantargo.1sg.pres.ind-sing ‘I sang’), but its existence in Occitan has been ignored to the extent that Catalan is often erroneously thought to be the only Romance language with ago-past. In this article, we first explore the rise and distribution of thego-past in Old Occitan (ca. 13th to 16th centuries) and then focus on the presence of the construction in the contemporary Occitan dialects of Gascony and Guardia Piemontese (a village in Calabria, Italy). We discuss the semantic and morphological particularities of the construction in some detail for both dialects using data from a variety of (little-known) sources, including, for Guardia Piemontese, our own field data. Finally, we provide arguments for the hypothesis that thego-past developed first in Occitania and subsequently diffused into Catalan-speaking areas.
Les adjectifs référentiels déictiques français actuel et présent
Authors: Vanderbauwhede Gudrun
Published: February 2015

In this paper, we present the results of a corpus-based synchronic study of the formal and semantic functioning of the French speech-act related referential adjectives actuel and présent. By analyzing different parameters, such as semantic use, position, gradability, coordination and lexicalization, we are able to distinguish between different polysemy and homonymy phenomena related to actuel and présent, to study more in detail their interchangeability capacities for their temporal uses and to show that, with respect to a prototype-based delineation, présent, and in a lesser way actuel, deviate on certain criteria and can be considered as less representative of the speech-act related referential adjective class in French.
A pilot study on quantification of training load: The use of HRV in training practice
Authors: Saboul Damien , Balducci Pascal , Millet Grégoire , Pialoux Vincent , Hautier Christophe
Published: February 2015

Recent laboratory studies have suggested that heart rate variability (HRV) may be an appropriate criterion for training load (TL) quantification. The aim of this study was to validate a novel HRV index that may be used to assess TL in field conditions. Eleven well‐trained long‐distance male runners performed four exercises of different duration and intensity. TL was evaluated using Foster and Banister methods. In addition, HRV measurements were performed 5 minutes before exercise and 5 and 30 minutes after exercise. We calculated HRV index (TLHRV) based on the ratio between HRV decrease during exercise and HRV increase during recovery. HRV decrease during exercise was strongly correlated with exercise intensity (R = −0.70; p < 0.01) but not with exercise duration or training volume. TLHRV index was correlated with Foster (R = 0.61; p = 0.01) and Banister (R = 0.57; p = 0.01) methods. This study confirms that HRV changes during exercise and recovery phase are affected by both intensity and physiological impact of the exercise. Since the TLHRV formula takes into account the disturbance and the return to homeostatic balance induced by exercise, this new method provides an objective and rational TL index. However, some simplification of the protocol measurement could be envisaged for field use.
Revisiting the SN1987A gamma-ray limit on ultralight axion-like particles
Authors: Payez Alexandre , Evoli Carmelo , Fischer Tobias , Giannotti Maurizio , Mirizzi Alessandro , Ringwald Andreas
Published: February 2015

We revise the bound from the supernova SN1987A on the coupling of ultralight axion-like particles (ALPs) to photons. In a core-collapse supernova, ALPs would be emitted via the Primakoff process, and eventually convert into gamma rays in the magnetic field of the Milky Way. The lack of a gamma-ray signal in the GRS instrument of the SMM satellite in coincidence with the observation of the neutrinos emitted from SN1987A therefore provides a strong bound on their coupling to photons. Due to the large uncertainty associated with the current bound, we revise this argument, based on state-of-the-art physical inputs both for the supernova models and for the Milky-Way magnetic field. Furthermore, we provide major amendments, such as the consistent treatment of nucleon-degeneracy effects and of the reduction of the nuclear masses in the hot and dense nuclear medium of the supernova. With these improvements, we obtain a new upper limit on the photon-ALP coupling:

gaγ≲ 5.3 × 10-12GeV-1, forma≲ 4.4 × 10-10eV,

and we also give its dependence at larger ALP massesma. Moreover, we discuss how much the Fermi-LAT satellite experiment could improve this bound, should a close-enough supernova explode in the near future.
Cell shape impacts on the positioning of the mitotic spindle with respect to the substratum
Authors: Lázaro-Diéguez Francisco , Ispolatov Iaroslav , Müsch Anne
Published: February 2015

All known mechanisms of mitotic spindle orientation rely on astral microtubules. We report that even in the absence of astral microtubules, metaphase spindles in MDCK and HeLa cells are not randomly positioned along their x-z dimension, but preferentially adopt shallow β angles between spindle pole axis and substratum. The nonrandom spindle positioning is due to constraints imposed by the cell cortex in flat cells that drive spindles that are longer and/or wider than the cell's height into a tilted, quasidiagonal x-z position. In rounder cells, which are taller, fewer cortical constraints make the x-z spindle position more random. Reestablishment of astral microtubule–mediated forces align the spindle poles with cortical cues parallel to the substratum in all cells. However, in flat cells, they frequently cause spindle deformations. Similar deformations are apparent when confined spindles rotate from tilted to parallel positions while MDCK cells progress from prometaphase to metaphase. The spindle disruptions cause the engagement of the spindle assembly checkpoint. We propose that cell rounding serves to maintain spindle integrity during its positioning.
PICK1 is implicated in organelle motility in an Arp2/3 complex–independent manner
Authors: Madasu Yadaiah , Yang Changsong , Boczkowska Malgorzata , Bethoney Kelley A. , Zwolak Adam , Rebowski Grzegorz , Svitkina Tatyana , Dominguez Roberto
Published: February 2015

PICK1 is a modular scaffold implicated in synaptic receptor trafficking. It features a PDZ domain, a BAR domain, and an acidic C-terminal tail (ACT). Analysis by small- angle x-ray scattering suggests a structural model that places the receptor-binding site of the PDZ domain and membrane-binding surfaces of the BAR and PDZ domains adjacent to each other on the concave side of the banana-shaped PICK1 dimer. In the model, the ACT of one subunit of the dimer interacts with the PDZ and BAR domains of the other subunit, possibly accounting for autoinhibition. Consistently, full-length PICK1 shows diffuse cytoplasmic localization, but it clusters on vesicle-like structures that colocalize with the trans-Golgi network marker TGN38 upon deletion of either the ACT or PDZ domain. This localization is driven by the BAR domain. Live-cell imaging further reveals that PICK1-associated vesicles undergo fast, nondirectional motility in an F-actin–dependent manner, but deleting the ACT dramatically reduces vesicle speed. Thus the ACT links PICK1-associated vesicles to a motility factor, likely myosin, but, contrary to previous reports, PICK1 neither binds nor inhibits Arp2/3 complex.
Examining Dynamically Changing Timber Market Linkages
Authors: Hood Harrison B. , Dorfman Jeffrey H.
Published: February 2015

Market integration has been widely studied in the past to gain a better understanding of how different markets for the same good interact with one another. Traditional cointegration tests have been used to perform these analyses; however, these tests can only reveal the presence of stable or average long‐term relationships. To evaluate market dynamics over time, we modify a time‐varying smooth transition autoregressive (TV‐STAR) model to examine pine stumpage markets in the US South. The proposed model incorporates an economic indicator and allows us to evaluate market integration as it changes throughout a specified time period. The potential significance of this work is twofold. First, market integration can be observed as a function of an economic indicator, and secondly, the proposed model will allow us to draw inference about market integration at specific time points.
Tetrahydroisoquinolines affect the whole-cell phenotype of Mycobacterium tuberculosis by inhibiting the ATP-dependent MurE ligase
Authors: Guzman Juan D. , Pesnot Thomas , Barrera Diana A. , Davies Heledd M. , McMahon Eleanor , Evangelopoulos Dimitrios , Mortazavi Parisa N. , Munshi Tulika , Maitra Arundhati , Lamming Eleanor D. , Angell Richard , Gershater Markus C. , Redmond Joanna M. , Needham Deborah , Ward John M. , Cuca Luis E. , Hailes Helen C. , Bhakta Sanjib
Published: February 2015

Objectives

(S)-Leucoxine, isolated from the Colombian Lauraceae tree Rhodostemonodaphne crenaticupula Madriñan, was found to inhibit the growth of Mycobacterium tuberculosis H37Rv. A biomimetic approach for the chemical synthesis of a wide array of 1-substituted tetrahydroisoquinolines was undertaken with the aim of elucidating a common pharmacophore for these compounds with novel mode(s) of anti-TB action.

Methods

Biomimetic Pictet–Spengler or Bischler–Napieralski synthetic routes were employed followed by an evaluation of the biological activity of the synthesized compounds.

Results

In this work, the synthesized tetrahydroisoquinolines were found to inhibit the growth of M. tuberculosis H37Rv and affect its whole-cell phenotype as well as the activity of the ATP-dependent MurE ligase, a key enzyme involved in the early stage of cell wall peptidoglycan biosynthesis.

Conclusions

As the correlation between the MIC and the half-inhibitory enzymatic concentration was not particularly strong, there is a credible possibility that these compounds have pleiotropic mechanism(s) of action in M. tuberculosis.
CD4 Recovery on Antiretroviral Therapy Is Associated With Decreased Progression to Liver Disease Among Hepatitis C Virus-Infected Injecting Drug Users
Authors: Anderson Jeffrey P. , Horsburgh C. Robert , Williams Paige L. , Tchetgen Tchetgen Eric J. , Nunes David , Cotton Deborah , Seage George R.
Published: February 2015

Background.  Human immunodeficiency virus (HIV) coinfection accelerates liver disease progression in individuals with chronic hepatitis C. We evaluated the associations of CD4, HIV RNA, and antiretroviral therapy (ART)-induced CD4 recovery with liver diagnoses in a prospective cohort of injecting drug users (IDUs).

Methods.  We evaluated 383 coinfected IDUs in the Boston area, prospectively observed for a median of 1.8 years. Liver disease progression included the first occurrence of hepatocellular carcinoma, variceal bleeding, ascites, encephalopathy, or death due to hepatic failure. Multivariable-adjusted extended Cox models were specified to estimate hazard ratios (HRs) for comparisons of CD4, change in CD4 (from nadir), and HIV RNA with respect to liver disease progression events.

Results.  Twenty-four persons experienced a liver disease progression event over 1155 person-years (2.1 per 100 person-years), including 20 deaths attributed to end-stage liver disease (1.7 per 100 person-years). CD4 at baseline and over follow-up strongly predicted liver disease progression (baseline CD4 <200 vs ≥200: HR = 5.23, 95% confidence interval [CI], 2.30–11.92; time-updated CD4 <200 vs ≥200: HR = 11.79, 95% CI, 4.47–31.07). Nadir CD4 was also a strong indicator (<100 vs ≥100: HR = 3.52, 95% CI, 1.54–8.06). A lack of CD4 recovery (failure to increase 100 cells over nadir) among ART initiators was associated with increased risk (HR = 7.69; 95% CI, 2.60–22.69). Human immunodeficiency virus RNA was not significantly associated with liver disease progression.

Conclusions.  Impaired immune function was highly predictive of liver disease progression in this cohort of IDUs, and a lack of CD4 recovery on ART was associated with increased risk of progression to HCV-associated liver disease.
Bacterial genome reduction using the progressive clustering of deletions via yeast sexual cycling
Authors: Suzuki Yo , Assad-Garcia Nacyra , Kostylev Maxim , Noskov Vladimir N. , Wise Kim S. , Karas Bogumil J. , Stam Jason , Montague Michael G. , Hanly Timothy J. , Enriquez Nico J. , Ramon Adi , Goldgof Gregory M. , Richter R. Alexander , Vashee Sanjay , Chuang Ray-Yuan , Winzeler Elizabeth A. , Hutchison Clyde A. , Gibson Daniel G. , Smith Hamilton O. , Glass John I. , Venter J. Craig
Published: February 2015

The availability of genetically tractable organisms with simple genomes is critical for the rapid, systems-level understanding of basic biological processes. Mycoplasma bacteria, with the smallest known genomes among free-living cellular organisms, are ideal models for this purpose, but the natural versions of these cells have genome complexities still too great to offer a comprehensive view of a fundamental life form. Here we describe an efficient method for reducing genomes from these organisms by identifying individually deletable regions using transposon mutagenesis and progressively clustering deleted genomic segments using meiotic recombination between the bacterial genomes harbored in yeast. Mycoplasmal genomes subjected to this process and transplanted into recipient cells yielded two mycoplasma strains. The first simultaneously lacked eight singly deletable regions of the genome, representing a total of 91 genes and ∼10% of the original genome. The second strain lacked seven of the eight regions, representing 84 genes. Growth assay data revealed an absence of genetic interactions among the 91 genes under tested conditions. Despite predicted effects of the deletions on sugar metabolism and the proteome, growth rates were unaffected by the gene deletions in the seven-deletion strain. These results support the feasibility of using single-gene disruption data to design and construct viable genomes lacking multiple genes, paving the way toward genome minimization. The progressive clustering method is expected to be effective for the reorganization of any mega-sized DNA molecules cloned in yeast, facilitating the construction of designer genomes in microbes as well as genomic fragments for genetic engineering of higher eukaryotes.
Crystal structure ofN1-phenyl-N4-[(E)-(pyren-1-yl)methylidene]benzene-1,4-diamine
Authors: Faizi Md. Serajul Haque , Prisyazhnaya Elena V.
Published: February 2015

In the title compound, C29H20N2, the dihedral angles subtended by the centralp-phenylenediamine ring with respect to the mean plane of the terminal pyrenyl ring system (r.m.s. deviation = 0.027 Å) and the terminalN-phenyl ring are 29.34 (4) and 43.43 (7)°, respectively. The conformation about the C=N bond isE. In the crystal, molecules are linked by N—H...π and C—H...π interactions forming chains propagating along the [10-2] direction. These chains are linkedviaπ–π interactions [inter-centroid distances are in the range 3.5569 (11)–3.708 (1) Å], forming slabs lying parallel to (30-4).
Crystal structure of chlorido(2-{1-[2-(4-chlorophenyl)hydrazin-1-ylidene-κN]ethyl}pyridine-κN)(η5-pentamethylcyclopentadienyl)rhodium(III) chloride
Authors: Devika Neelakandan , Raja Nandhagopal , Ananthalakshmi Subbiah , Therrien Bruno
Published: February 2015

The cation of the title compound, [Rh(η5-C5Me5)Cl(C13H12ClN3)]Cl, adopts a typical piano-stool geometry. The complex is chiral at the metal and crystallizes as a racemate. Upon coordination, the hydrazinylidenepyridine ligand is non-planar, an angle of 54.42 (7)° being observed between the pyridine ring and the aromatic ring of the [2-(4-chlorophenyl)hydrazin-1-ylidene]ethyl group. In the crystal, a weak interionic N—H...Cl hydrogen bond is observed.
Crystal structure of 15-(naphthalen-1-yl)-7,7a,8,9,10,11-hexahydro-6a,12a-(methanoepoxymethano)indolizino[2,3-c]quinoline-6,13(5H)-dione
Authors: Savithri M. P. , Suresh M. , Raghunathan R. , Raja R. , SubbiahPandi A.
Published: February 2015

In the title compound, C27H24N2O3, the dihedral angle between the mean planes of the dihydrofuran and 3,4-dihydroquinoline ring systems is 70.65 (9)°. The dihydrofuran ring adopts an envelope conformation with the C atom adjacent to the methylene C atom of the pyrrolidine ring as the flap. The five-membered pyrrolidine ring adopts a twist conformation on the N—C(tetrasubstituted) bond. In the crystal, molecules are linkedviapairs of N—H...O hydrogen bonds, forming inversion dimers with anR22(8) ring motif. The dimers are linkedviapairs of C—H...O hydrogen bonds, forming ribbons enclosingR22(12) ring motifs lying in a plane parallel to (01-1).
Crystal structure of 3-[2-(thiophen-3-yl)ethynyl]-2H-chromen-2-one
Authors: Caracelli Ignez , Maganhi Stella H. , Stefani Hélio A. , Gueogjian Karina , Tiekink Edward R. T.
Published: February 2015

In the title compound, C15H8O2S, the coumarin moiety is approximately planar (r.m.s. deviation of the 11 non-H atoms = 0.025 Å) and is slightly inclined with respect to the plane of the thiophen-3-yl ring, forming a dihedral angle of 11.75 (8)°. In the crystal, the three-dimensional architecture features a combination of coumarin–thiophene C—H...π and π–π [inter-centroid distance = 3.6612 (12) Å] interactions.
Crystal structure of [1-(2,6-diisopropylphenyl)-2,4-bis(dimethylamino)-5-trimethylsilyl-1,3,5-triazapentadienyl-κ2N1,N5](triphenylphosphane-κP)copper(I)
Authors: Li Feiguang , Yan Lei , Tong Hongbo , Zhou Meisu
Published: February 2015

The title complex, [Cu(C21H38N5Si)(C18H15P)], was obtained from the one-pot reaction between (Dipp)N(Li)SiMe3(Dipp = 2,6-diisopropylphenyl), Me2NCN, CuCl and PPh3. The CuIatom has a distorted trigonal–planar coordination sphere. The triazapentadienyl ligand acts as a κ2-donor. The N—Cu—N bond angle is 95.88 (14)°. In the triazapentadienyl fragment, the C—N bond lengths are in the range 1.328 (5)–1.349 (5) Å, which indicates delocalization of the π-electrons in the NCNCN system.
Crystal structure of (Z)-2-(1-benzyl-2-oxoindolin-3-ylidene)-N-phenylhydrazine-1-carbothioamide
Authors: Vimala G. , Haribabu J. , Karvembu R. , Kumar B. V. N. Phani , SubbiahPandi A.
Published: February 2015

The title compound, C22H18N4OS, crystallized with four independent molecules (A,B,CandD) in the asymmetric unit. All four molecules have aZconformation about the C=N bond with the benzyl ring being inclined to the indoline ring mean planes by 73.4 (2), 77.9 (2), 73.2 (2) and 77.2 (2)° in moleculesA,B,CandD, respectively. In moleculesAandB, the phenyl ring is inclined to the mean plane of the indoline ring mean plane by 12.0 (2) and 12.2 (2)°, respectively. However, in moleculesCandD, the same dihedral angles are larger,viz.37.3 (2) and 36.4 (2)°, respectively. Consequently, the benzyl and phenyl rings are almost normal to one another in moleculesAandB[dihedral angles = 80.3 (3) and 87.1 (3)°, respectively], while in moleculesCandD, the same dihedral angles are only 48.8 (2) and 43.8 (3)°, respectively. There is an intramolecular N—H...O hydrogen bond in each molecule with anS(6) ring motif. There are also short intramolecular N—H...N and C—H...S contacts in each molecule. In the crystal, molecules are linkedviaC—H...S hydrogen bonds and C—H...π interactions, forming a three-dimensional structure. The crystal was refined as a non-merohedral twin with a final BASF value of 0.110 (1).
International manufacturing network: past, present, and future
Authors: Cheng Yang , Farooq Sami , Johansen John
Published: February 2015

Purpose

– The purpose of this paper is to examine, and present a comprehensive review of, the existing literature on the international manufacturing network (IMN).

Design/methodology/approach

– The original data set used for reviewing the IMN literature consisted of 107 articles selected from 21 journals: more specifically, 40 articles are concerned with plant-level analysis, and 67 articles are related to IMN-level analysis. The literature is simultaneously reviewed by two researchers. The relevance and contribution of each reviewed paper is discussed and mutually agreed upon.

Findings

– The paper highlights the different concepts related to IMN and traces the evolution of IMN-related research. Based on two levels of analysis (i.e. plant and network), this paper further reviews and discusses the IMN-specific literature in detail to determine the number of IMN articles published across the journals, the dominant methodologies employed, and the research focus reflected in IMN studies. A research trajectory is finally developed to provide an integrated and intuitional view on the development of IMN research.

Originality/value

– This is the first effort that has been made towards thoroughly investigating the existing literature on IMN, aiming to trace different concepts related to IMN from a historical perspective, to review and discuss the IMN-specific literature in detail, to provide an overview of the evolution trajectory of different existing IMN research themes, and to propose future research directions. Keeping in mind the growing importance of IMN for practitioners as well as the academic community, this study provides a timely overview of existing and emerging IMN research themes.