bluuebunny/crossref_metadata_2025 huggingface dataset:
From zero-dimensional to one-dimensional chain N-oxide bridged compounds with enhanced single-molecule magnetic performance
Authors: Zhang Ling , Chen Peng , Li Hong-Feng , Tian Yong-Mei , Yan Peng-Fei , Sun Wen-Bin
Published: February 2019

A series of zero-dimensional dinuclear dysprosium complexes bridged by pyridine-NO ligands were extended by double N-oxide bridged ligand to series of one-dimensional chain complexes with repeated Dy2 unit, they were structurally and magnetically characterized in this work.
An oxygen-bridged triarylamine polycyclic unit based tris-cyclometalated heteroleptic iridium(iii) complex: correlation between the structure and photophysical properties
Authors: Li Qiuxia , Zhang Xinghua , Cao Yibo , Shi Chao , Tao Peng , Zhao Qiang , Yuan Aihua
Published: February 2019

A novel oxygen-bridged triarylamine polycyclic based tris-cyclometalated heteroleptic iridium(iii) complex has been prepared and shows unusual excited state properties.
DNA interaction of ruthenium(ii) complexes with imidazo[4,5-f][1,10]phenanthroline derivatives
Authors: Yu Bole , Rees Thomas W. , Liang Jiewen , Jin Chengzhi , Chen Yu , Ji Liangnian , Chao Hui
Published: February 2019

The DNA interaction properties of four Ru(ii) complexes with imidazo[4,5-f][1,10]phenanthroline derivatives were investigated by spectral titration, gel electrophoresis (GAR), dynamic light scattering (DLS), zeta potential, atomic force microscopy (AFM), and transmission electron microscopy (TEM).
First-row early transition metal complexes with a highly sterically demanding triisopropylphenyl amino triphenolate ligand: synthesis and applications
Authors: Bae Dae Young , Park Gyeong Su , Ko Nakeun , Son Kyung-sun , Lee Eunsung
Published: February 2019

A highly sterically demanding amino triphenolate ligand was successfully synthesized, and early transition metal complexes (Ti, V, Cr, and Mn) supported by the ligand were also obtained and fully characterized.
A hybrid fluoride layered perovskite, (enH2)MnF4
Authors: Li Teng , Clulow Rebecca , Bradford Alasdair J. , Lee Stephen L. , Slawin Alexandra M. Z. , Lightfoot Philip
Published: February 2019

The title compound represents the first example of a hybrid layered fluoride perovskite.
Cu2S nanosheets for ultrashort pulse generation in the near-infrared region
Authors: Hui Zhanqiang , Xu Wenxiong , Li Xiaohui , Guo Penglai , Zhang Ying , Liu Jishu
Published: February 2019

The nonlinear optical properties of cuprous sulfide have been studied. The successful application in Er-doped fiber laser has proved cuprous sulfide as a novel, promising materials in the field of ultra-fast photonics.
Mechanical behaviour of contractile gels based on light-driven molecular motors
Authors: Colard-Itté Jean-Rémy , Li Quan , Collin Dominique , Mariani Giacomo , Fuks Gad , Moulin Emilie , Buhler Eric , Giuseppone Nicolas
Published: February 2019

Rotary molecular motors that function as mechanically active reticulation nodes actuate contractile gels and increase their elastic modulus.
Correction: A highly antibacterial polymeric hybrid micelle with efficiently targeted anticancer siRNA delivery and anti-infection in vitro/in vivo
Authors: Zhou Li , Xi Yuewei , Chen Mi , Niu Wen , Wang Min , Ma Peter X. , Lei Bo
Published: February 2019

Correction for ‘A highly antibacterial polymeric hybrid micelle with efficiently targeted anticancer siRNA delivery and anti-infection in vitro/in vivo’ by Li Zhou et al., Nanoscale, 2018, 10, 17304–17317.
Synthesis, structural characterisation, and synthetic application of stable seleniranium ions
Authors: Bock Jonathan , Daniliuc Constantin G. , Bergander Klaus , Mück-Lichtenfeld Christian , Hennecke Ulrich
Published: February 2019

Stable seleniranium ions were prepared, their solid state structures determined and their application as highly efficient selenenylating agents was demonstrated.
Catalyst-free direct cross-dehydrogenative coupling of imidazoheterocycles with glyoxal hydrates: an efficient approach to 1,2-diketones
Authors: Guo Tao , Fu Xiang-Heng , Zhang Miao , Li Yu-Liu , Ma Yong-Cheng
Published: February 2019

An efficient and convenient catalyst-free synthesis of 1,2-diketones via cross-dehydrogenative coupling of imidazoheterocycles with glyoxal hydrates is described.
Modular synthesis and immunological evaluation of suspected allergenic galactooligosaccharides
Authors: Elferink Hidde , Rossing Emiel , Huang Chiung-Hui , Lee Bee Wah , Cao Linqiu , Delsing Dianne J. , Groeneveld Andre , Boltje Thomas J.
Published: February 2019

The synthesis of suspected GOS-related allergens using a flexible modular approach and their immunological evaluation are reported.
Asymmetric total synthesis of (+)-asenapine
Authors: Szcześniak Piotr , Staszewska-Krajewska Olga , Mlynarski Jacek
Published: February 2019

Asymmetric total synthesis of (+)-asenapine involving the organocatalytic Michael addition reaction and subsequent Zn-promoted reductive cyclization as the key steps.
Lewis base catalyzed regioselective cyclization of allene ketones or α-methyl allene ketones with unsaturated pyrazolones
Authors: Cheng Cheng , Sun Xiaobin , Wu Zelin , Liu Qianwei , Xiong Liqiang , Miao Zhiwei
Published: February 2019

Highly efficient nitrogen-containing Lewis base catalyzed regioselective [4 + 2] cycloaddition of allene ketones or α-methyl allene ketones with unsaturated pyrazolones.
Synthesis of monodisperse aromatic azo oligomers toward gaining new insight into the isomerization of π-conjugated azo systems
Authors: Liu Meng , Yin Lu , Wang Laibing , Miao Tengfei , Cheng Xiaoxiao , Wang Yong , Zhang Wei , Zhu Xiulin
Published: February 2019

The unique E → Z photoisomerization mechanism of monodisperse fluorene-azo oligomers was studied and the trans-[trans–trans]n-cis model was proposed. This novel model will give new insight into the isomerization of π-conjugated azo systems.
Rhodium(iii)-catalyzed diverse [4 + 1] annulation of arenes with 1,3-enynes via sp3/sp2 C–H activation and 1,4-rhodium migration
Authors: Bai Dachang , Xia Jintao , Song Fangfang , Li Xueyan , Liu Bingxian , Liu Lihong , Zheng Guangfan , Yang Xifa , Sun Jiaqiong , Li Xingwei
Published: February 2019

Novel azacycles were synthesized through rhodium(iii)-catalyzed sp2 and sp3 C–H activation-oxidative annulations between arenes and 1,3-enynes.
Melatonin suppresses lung cancer metastasis by inhibition of epithelial–mesenchymal transition through targeting to Twist
Authors: Chao Chia-Chia , Chen Po-Chun , Chiou Pei-Chen , Hsu Chin-Jung , Liu Po-I , Yang Yi-Chen , Reiter Russel J. , Yang Shun-Fa , Tang Chih-Hsin
Published: February 2019

The epithelial–mesenchymal transition (EMT) phenotype, whereby mature epithelial cells undergo phenotype transition and differentiate into motile, invasive cells, has been indicated in tumor metastasis. The melatonin hormone secreted by the pineal gland has an antioxidant effect and protects cells against carcinogenic substances that reduce tumor progression. However, the effects of melatonin in EMT and lung cancer metastasis are largely unknown. We found that melatonin down-regulated EMT by inhibiting Twist/Twist1 (twist family bHLH transcription factor 1) expression. This effect was mediated by MT1 receptor, PLC, p38/ERK and β-catenin signaling cascades. Twist expression was positively correlated with tumor stage and negatively correlated with MT1 expression in lung cancer specimens. Furthermore, melatonin inhibited EMT marker expression and lung cancer metastasis to liver in vivo. Finally, melatonin shows promise in the treatment of lung cancer metastasis and deserves further study.
Eligibility and Speech Sound Disorders: Assessment of Social Impact
Authors: Krueger Breanna I.
Published: February 2019

Purpose

The purpose of this article is to discuss the social impact of speech sound disorders for children, specifically in the public school system, and to examine different methods of social impact assessment for speech-language therapy services using 3 hypothetical cases.

Method

This article presents 3 common cases seen by school-based speech-language pathologists and discusses the types of assessments that may be conducted for each child's needs. One child has errors on many sounds, 1 child has errors on only /r/, and 1 child produces strident sounds with a lateral lisp.

Results

As these are hypothetical cases, possibilities are discussed for each case. Similarities and differences exist among the 3 cases in terms of assessing the social impact of their speech sound disorder; however, each child could qualify for services based on social impact assessments.

Conclusion

Social impact assessments are an important portion of a speech sound evaluation; however, they are often overlooked. Emphasis is placed on articulation assessments and/or commonly accepted developmental norms. The determination of social impact supplies a more complete picture for making eligibility decisions for children with speech sound disorders and may lead to more meaningful treatment methods for the student.
c2AIDER: cognitive cloud exoskeleton system and its applications
Authors: Wang Yilin , Cheng Hong , Hou Lei
Published: February 2019

Lower extremity exoskeleton systems have been widely applied in walking assistance, rehabilitation, and augmentation‐related applications merely through human‐exoskeleton movement collaboration, which cannot analyse cognitive load and pressure of pilots. Cognitive exoskeleton systems can reinforce cognitive cooperation of the human‐exoskeleton systems through perception and assessment. Cognitive cloud exoskeleton systems can enhance the ability of the continuous learning and transfer learning of the exoskeleton systems through cloud brain platform. This paper presents a cognitive cloud exoskeleton system Cognitive Cloud AssItive DEvice for paralysed patient (c2AIDER). The main idea is that the cooperation between the c2AIDER system and pilots is more intelligent and natural through cloud brain platform, which can achieve high‐performance computing thus providing better walking assistance for pilots.
Cramér–Rao lower bound for ATSC signal‐based passive radar systems
Authors: Alslaimy M. , Smith G.E.
Published: February 2019

In multistatic passive radar systems, the Cramér–Rao lower bound (CRLB) can be used to select the optimal illuminator of opportunity so that it provides the best estimation accuracy for target parameters. In this Letter, the monostatic and bistatic modified Cramér–Rao lower bound (MCRLB) for the Advanced Television Systems Committee (ATSC) signal, which is the pervasive digital television signal of opportunity for North American passive radar systems, is derived using the relationship between the ambiguity function of a signal and its CRLB. It is shown that the derived bistatic MCRLB for the range and velocity measurements can be used to select the optimal illuminator that exhibits the lowest bounds at each region. Examples are provided in the Columbus, OH area where the Ohio State University passive radar is located.
Weakly supervised segment annotation via expectation kernel density estimation
Authors: Wang Liantao , Li Qingwu , Lu Jianfeng
Published: February 2019

Since the labelling for the positive images/videos is ambiguous in weakly supervised segment annotation, negative mining‐based methods that only use the intra‐class information emerge. In these methods, negative instances are utilised to penalise unknown instances for ranking their likelihood of being an object, which can be considered as voting in terms of similarity. However, these methods (i) ignore the information contained in positive bags; (ii) only rank the likelihood but cannot generate an explicit decision function. In this study, the authors propose a voting scheme involving not only the definite negative instances but also the ambiguous positive instances to make use of the extra useful information in the weakly labelled positive bags. In the scheme, each instance votes for its label with a magnitude arising from the similarity, and the ambiguous positive instances are assigned soft labels that are iteratively updated during the voting. It overcomes the limitations of voting using only the negative bags. They also propose an expectation kernel density estimation algorithm to gain further insight into the voting mechanism. Experimental results demonstrate the superiority of the authors’ scheme beyond the baselines.
Sub‐band mutual‐coherence compensation in multiband fusion ISAR imaging
Authors: Xiong Di , Wang Junling , Zhao Lizhi , Yuan Zhengkun , Gao Meiguo
Published: February 2019

Phase‐coherence of signals in different sub‐bands is a prerequisite for multiband fusion radar imaging. Here, a mutual‐coherence compensation method based on valid dominant poles and phase autofocusing is proposed to compensate for the incoherent phases (ICPs) between sub‐bands in multiband fusion inverse synthetic aperture radar (ISAR) imaging. In the proposed method, the linear ICP compensation and fixed ICP compensation are decoupled rather than the ICPs being compensated pulse by pulse as in traditional methods. In this method, the valid dominant poles that correspond to strong scatterers in the estimated poles of each sub‐band are first extracted to estimate the linear ICP. Then, phase autofocusing technology based on the same rotation centre is applied to multiple pulses in each sub‐band in the ISAR coherently processing time to jointly compensate for all the fixed ICPs at once. Furthermore, a unitary estimation of signal parameters via the rotational invariance techniques (U‐ESPRIT) method, which can exploit considerable information from the measured data, is utilised to estimate the poles of the sub‐bands to improve the accuracy of the estimation of the linear ICP between sub‐bands. The effectiveness and robustness of the method were verified experimentally based on both numerical simulations and real data.
Plane dimension detection with a single camera based on a flat refractive camera model
Authors: Xu Dong , Liu Kedong , Yang Quan , Dong Feng , Wang Xiaochen , Dai Zhenyang
Published: February 2019

It is common that a pinhole camera captures object images through a transparent plate with two parallel planar faces. In this case, the refraction leads to a non‐linear error using the simple pinhole model. To address this issue, a modified pinhole camera model, which is called flat refractive camera model, is established based on the analysis of light refraction in the transparent plate placed between the scene and the camera. Then, an effective backward‐projection algorithm is proposed to realise plane dimension detection and eliminate the plate refraction effect. Unlike other models, this proposed model has a form similar to the pinhole camera model. Therefore, it is easy to employ conventional vision techniques in the plate imaging system. At the same time, experiments are designed to demonstrate the plane dimension detection based on the proposed method. Experimental results show that the proposed method can obtain higher accuracy than the traditional method without considering the plate refraction effect.
Non‐linear extended state observer‐based sliding mode control for a direct‐driven wind energy conversion system with permanent magnet synchronous generator
Authors: Tang Yongwei , Li Juan , Li Shengquan , Cao QingFeng , Wu Yuanwang
Published: February 2019

Considering the internal and external disturbances of direct‐driven wind turbine‐based permanent magnet synchronous generation system, an extended state observer (ESO)‐based sliding mode variable structure control strategy is proposed to improve the maximum power tracking performance of the system. The ESO is used to estimate the effects of the disturbances, such as dynamical uncertainties, modelling error, external forces, variety of wind speed and so on, and eliminate the disturbances by the feedforward compensation. The simulation results show that the control system not only effectively improves the anti‐disturbance ability of the system, but also solves the chattering problem of sliding mode control system to a certain extent.
Accretion disk versus jet orientation in H2O megamaser galaxies
Authors: Kamali F. , Henkel C. , Koyama S. , Kuo C. Y. , Condon J. J. , Brunthaler A. , Reid M. J. , Greene J. E. , Menten K. M. , Impellizzeri C. M. V. , Braatz J. A. , Litzinger E. , Kadler M.
Published: February 2019

Context. An essential part of the paradigm describing active galactic nuclei is the alignment between the radio jet and the associated rotation axis of the sub-pc accretion disks. Because of the small linear and angular scales involved, this alignment has not yet been checked in a sufficient number of low luminosity active galactic nuclei (LLAGNs).

Aims. The project examines the validity of this paradigm by measuring the radio continuum on the same physical scale as the accretion disks to investigate any possible connection between these disks and the radio continuum.

Methods. We observed a sample of 18 LLAGNs in the 4.8 GHz (6 cm) radio continuum using the Very Long Baseline Array (VLBA) with 3.3–6.5 ms resolution. The sources were selected to show both an edge-on accretion disk revealed by 22 GHz H2O megamaser emission and signatures of a radio jet. Furthermore, the sources were previously detected in 33 GHz radio continuum observations made with the Very Large Array.

Results. Five out of 18 galaxies observed were detected at 8σ or higher levels (Mrk 0001, Mrk 1210, Mrk 1419, NGC 2273, and UGC 3193). While these five sources are known to have maser disks, four of them exhibit a maser disk with known orientation. For all four of these sources, the radio continuum is misaligned relative to the rotation axis of the maser disk, but with a 99.1% confidence level, the orientations are not random and are confined to a cone within 32° of the maser disk’s normal. Among the four sources the misalignment of the radio continuum with respect to the normal vector to the maser disk is smaller when the inner radius of the maser disk is larger. Furthermore, a correlation is observed between the 5 GHz VLBA radio continuum and the [OIII] luminosity and also with the H2O maser disk’s inner radius.
General lot-sizing and scheduling for perishable food products
Authors: Alipour Zohreh , Jolai Fariborz , Monabbati Ehsan , Zaerpour Nima
Published: February 2019

General lot-sizing and scheduling is a well-studied problem in the literature, but for perishable or time-sensitive products is less investigated. Also, most of studies on perishable product supply chains focus on strategic and tactical decision levels rather than operational decision level and integrated operational and tactical decision levels. We focus on a general lot-sizing and scheduling problem faced by perishable food products. The lifespan and shelf life are two important key features of perishable products that are considered in the problem. This problem can be described as a multi-product, multi-parallel line, multi-period general lot-sizing and scheduling problem with sequence dependent change over time. The objective function is sum of production costs, inventory holding costs, waste costs, and lifespan related cost function. We apply two mixed-integer programming based heuristics to solve generated instances. The heuristics are compared in terms of solution quality and computational time. Also, the sensitivity analysis is presented to analyze the effects of parameters’ changes.
Radiation therapy planning using MRI-CT fusion in dogs and
cats with brain tumors
Authors: Buchholz Julia , Ludewig Eberhard , Brühschwein Andreas , Nitzl Dagmar , Sumova Andrea , Kaser-Hotz Barbara
Published: February 2019

Introduction Volume definition is a delicate step within the radiation
treatment planning process and the precision of defining the volumes to
irradiate is important for the success of the radiation treatment.
Traditionally, radiation plans are created using computed tomography (CT)
studies. Due to its different mechanism of action, magnetic resonance imaging
(MRI) is more sensitive for detection of brain lesions. Therefore, using fused
images of both imaging modalities should result in a more precise definition of
the volumes to irradiate. The feasibility to fuse CT and MRI studies performed
at different institutions was tested to subsequently analyse the influence of
the fused images on target volume definition.

Materials and methods Fourteen dogs and four cats with brain lesions
having MR- and CT-imaging were included. Contrast-enhanced radiotherapy planning
CT scans were fused to T1-weighted post-contrast and T2-weighted MRI scans. The
gross tumor volume (GTV), the clinical tumor volume (CTV) and the planning
target volume (PTV) were delineated on CT- and MRI studies. CT and MRI volumes
were compared with regard to volumetric and spatial differences.

Results The mean GTV was larger on MRI than on CT (2.15 vs.1.54
cm3). Also the mean CTV was larger on MRI than on CT (5.34 vs.
4.38 cm3). Consequently, the mean PTV was larger on MRI than on CT
(14.20 vs. 10.82 cm3) as well. None of the differences in defined
volumes were significant. Fusion images were accepted showing mean errors of
1.32 mm (mean error) and 1.73 mm (maximal error).

Conclusion CT-MRI fusion was feasible especially when defined, reliable,
and consistent anatomic landmarks were used as registration points. Volumetric
differences between CT and MRI were insignificant. In general, GTV and CTV were
easier identified on MRI.
Bilateral femoral capital physeal fractures in an adult cat
with suspected congenital primary hypothyroidism
Authors: Diehm Marius , Dening Ricarda , Dziallas Peter , Wohlsein Peter , Schmicke Marion , Mischke Reinhard
Published: February 2019

A 4-year-old, neutered male European shorthair was presented for evaluation of
right hind limb lameness. Radiographs revealed bilateral femoral capital physeal
fractures, widened vertebral growth plates and constipation. Physical findings
included lethargy, mental dullness, mild hypothermia, retarded growth,
pharyngeal stridor, moderate muscle atrophy of pelvic limbs, hair coat
abnormalities, and lack of defecation and urination. A thyroid panel revealed
thyroid hormone values below detection limits and high thyroid stimulation
hormone values. A presumptive diagnosis of congenital primary hypothyroidism was
made, however also an early onset acquired primary hypothyroidism could not be
ruled out. Results of the insulin-like growth factor (IGF-1) and the parathyroid
hormone as well as an adrenocorticotropic hormone stimulating test were normal.
A bilateral femoral head and neck excision was performed. Levothyroxine
supplementation was started at a dosage of 50 µg (11 µg/kg) BID and later
adjusted to 100 µg (22 µg/kg) BID based on total thyroxine concentrations. The
tomcat showed full clinical recovery and normal clinical behaviour. The case
shows that primary hypothyroidism may be considered in cats presented with
femoral capital physeal fractures.
Translating antimicrobial resistance: a case study of context and consequences of antibiotic-related communication in three northern Thai villages
Authors: Charoenboon Nutcha , Haenssgen Marco J. , Warapikuptanun Penporn , Xayavong Thipphaphone , Khine Zaw Yuzana
Published: February 2019

Antimicrobial resistance (AMR) threatens to cause ten million deaths annually by 2050, making it a top item on the global health agenda. The current global policy response is multi-faceted, wherein behavioural dimensions like people’s medicine use are being predominantly addressed with education and communication campaigns. The social sciences literature suggests that cross-contextual translation of medical knowledge in global awareness campaigns can create misunderstandings and adverse behavioural responses. However, the consequences of AMR communication in low-income and middle-income contexts remain largely undocumented. In response to the empirical knowledge gap, this study presents the case study of educational activity in three northern Thai villages with the objective of contributing to the understanding of the consequences (and their contextual influences) when sharing antibiotic-related information in a rural middle-income setting. The activity’s messages were based on World Health Organization AMR awareness-raising material. A mixed-methods research design informed the analysis. Descriptive difference-in-difference and geographical analysis based on complete village census surveys with a 3-month interval (n = 1096) was supplemented by qualitative data and observations from the educational activity. The underlying conceptual framework hypothesised that outcomes arise via (a) direct participation and indirect exposure (posters, conversations), subject to translational processes and physical and health system contexts; and via (b) the activity’s influence on village social networks. The outcomes demonstrated that participants aligned their antibiotic-related attitudes and behaviours with the activity’s recommendations. Aside from language barriers (which excluded non-Thai speakers), fragmented local healthcare landscapes limited villagers’ ability to act on the activity but also provided a market opportunity for informal antibiotics sales, and interactions with parallel yet misunderstood public health campaigns created rumours and resistance. Social support from community members also promoted healthy behaviours but remained unaffected by the activity. As one of the most detailed mixed-method assessments of public engagement in AMR, this study challenges the current dominance of awareness-raising campaigns to change population behaviours. We call for comprehensive mixed-method evaluations of future campaigns, mandatory two-directional knowledge exchange components, and alternative behaviour change approaches that respond to contextual constraints like precarity rather than alleged knowledge deficits.
Cultural entrenchment of folktales is encoded in language
Authors: Karsdorp Folgert , Fonteyn Lauren
Published: February 2019

In this interdisciplinary study, we explore the understudied effects of growing cultural entrenchment on the form of stories with a long reproduction history. Drawing on insight from literary theory, theoretical linguistics, and cultural evolution theory, we argue that changes in the cultural entrenchment of fairy tales and folk stories are reflected in (small) structural ‘mutations’ in the story. More specifically, we aim to show that with the increasing familiarity of “Little Red Riding Hood”, its story frame and characters have gradually become part of the author and audience’s shared world knowledge, which is encoded in the type of linguistic devices used to introduce the characters. To this end, we performed a Bayesian logistic regression analysis on a diachronic collection (late 18th century–2015) of the world’s most iconic fairy tale, using automatically generated time estimations for a subset of undated reproductions in the story lineage, and including these estimates and approximated measurement errors in the statistical model. Results show that there is indeed a marked increase of linguistic markers that indicate that the characters are already known or “accessible” to the audience. This development reflects the author’s changing intuitions and beliefs about the familiarity of the story, and, indirectly, the changing expectations of the story’s audience regarding the appearance of certain characters in the story frame. Notably, this study is the first to quantitatively describe the diachronic development of a story (and the concepts associated with it) into the realm of ‘shared knowledge’, showing that it is a slow and gradual process. The results help refine our understanding of cultural evolution as well as the workings of speaker-addressee dynamics. Conceptualising the observed linguistic mutations as an instance of guided variation, we argue that the increase of definite first mentions as a function of cultural entrenchment can be treated as an example of variation guided by pragmatic principles such as Grice’s Maxim of Quantity, making character introductions as informative as (and not more informative than) required.
Optimization of energy transport in the Fenna-Matthews-Olson complex via site-varying pigment-protein interactions
Authors: Oh S. A. , Coker D. F. , Hutchinson D. A. W.
Published: February 2019

Energy transport in photosynthetic systems can be tremendously efficient. In particular, we study exciton transport in the Fenna-Mathews-Olson (FMO) complex found in green sulphur bacteria. The exciton dynamics and energy transfer efficiency depend on the interaction of excited chromophores with their environment. Based upon realistic, site-dependent models of the system-bath coupling, we present results that suggest that this interaction may be optimized in the case of FMO. Furthermore we verify two transport pathways and note that one is dominated by coherent dynamics and the other by incoherent energy dissipation. In particular, we note a significant correlation between energy transport efficiency and coherence for exciton transfer from bacteriochlorophyll (BChl) 8 to BChl 4.
Feasibility of imaging in nuclear magnetic resonance force microscopy using Boltzmann polarization
Authors: de Wit M. , Welker G. , Wagenaar J. J. T. , Hoekstra F. G. , Oosterkamp T. H.
Published: February 2019

We report on magnetic resonance force microscopy measurements of the Boltzmann polarization of nuclear spins in copper by detecting the frequency shift of a soft cantilever. We use the time-dependent solution of the Bloch equations to derive a concise equation describing the effect of radio-frequent (RF) magnetic fields on both on- and off-resonant spins in high magnetic field gradients. We then apply this theory to saturation experiments performed on a 100 nm thick layer of copper, where we use the higher modes of the cantilever as a source of the RF field. We demonstrate a detection volume sensitivity of only (40nm)3, corresponding to about 1.6×104 polarized copper nuclear spins. We propose an experiment on protons where, with the appropriate technical improvements, frequency-shift based magnetic resonance imaging with a resolution better than (10nm)3 could be possible. Achieving this resolution would make imaging based on the Boltzmann polarization competitive with the more traditional stochastic spin-fluctuation based imaging, with the possibility to work at millikelvin temperatures.
Novel nonlinear mechanism of the generation of non-thermal continuum radiation
Authors: Horký Miroslav , Omura Yoshiharu
Published: February 2019

We study a novel nonlinear mechanism which could be responsible for the generation of the non-thermal continuum radiation. We propose a mathematical model and perform numerical simulations using 2-D electromagnetic code KEMPO2 to verify the proposed mechanism. In the simulation domain, we have density gradient and ring beam electrons in the dense region as a source of electrostatic (ES) waves through ring-beam instability. These ES waves cause non-gyrotropy of the ring velocity distribution which is necessary for the generation of the harmonic waves. Velocity component vy together with magnetic field Bz of generated Z-mode waves creates Lorentz force in the x-direction (along the magnetic field). Hence, oscillating electrons emit O-mode waves to the low density area.
Two-dimensional thin shell model for the nonlinear Rayleigh-Taylor instability in spherical geometry
Authors: Zhao K. G. , Xue C. , Wang L. F. , Ye W. H. , Wu J. F. , Ding Y. K. , Zhang W. Y. , He X. T.
Published: February 2019

A two-dimensional thin shell model has been developed for the Rayleigh-Taylor instability in spherical geometry. The present model generalizes the work of Ott [Phys. Rev. Lett. 29, 1429 (1972)] to the case of spherical geometry. The governing equations for the shell motion and the deformation are obtained analytically and solved numerically. The linear growth rates from our model agree well with those from Mikaelian’s work but are slightly larger than those from the classical prediction for low-mode perturbations. The perturbation amplitudes and bubble velocities from our model are in general agreement with those from the weakly nonlinear model of Zhang [Phys. Plasmas 24, 062703 (2017)] and Layzer’s model [Astrophys. J. 122, 1 (1955)], respectively. Moreover, the present model can investigate the shell evolution initialized by multimode axisymmetric perturbations in spherical geometry.
Dynamic assessment of dual-frequency microbubble-mediated sonothrombolysis in vitro
Authors: Suo Dingjie , Govind Bala , Gu Juanjuan , Dayton Paul A. , Jing Yun
Published: February 2019

Optimizing the use of high intensity focused ultrasound (HIFU) for recanalization of occluded blood vessels is an actively researched area. This yields an alternative therapy to the use of thrombolytic drugs in the treatment of ischemic stroke. HIFU treatment, used in conjunction with microbubbles (MBs) in the fluid stream, serves to augment the dissipation of the blood clot. In this study, using an in vitro approach, we implement a flow system to simulate the dynamic dispersion of blood clots using single-frequency focused ultrasound (SFFU) and dual-frequency focused ultrasound (DFFU). The effects of permutations of acoustic power and driving frequency (SFFU vs. DFFU) on the rate of disintegration and site-specific lytic action are quantified under the influence of fluid akin to that in a blood vessel, for specific microbubble concentrations. It is found that dual-frequency excitation in general produces a faster rate of clot dissipation in comparison to single-frequency excitation, and this observation is corroborated by cavitation signal detection. Our observations indicate that accelerated thrombolysis may be realized by the inertial cavitation threshold of DFFU being lower than that of SFFU. Furthermore, the thrombolytic effect with variance in microbubble concentration is studied for a fixed acoustic power. The efficacy of DFFU is not found to vary appreciably with an increase in microbubble concentration from 108 MBs/ml to 109 MBs/ml, possibly due to acoustic shadowing induced at increased concentrations.
Doping dependence of the optical dielectric function in n-type germanium
Authors: Xu Chi , Kouvetakis John , Menéndez José
Published: February 2019

The doping dependence of the most important optical transitions in n-type Ge (E0, Eind, E1, E1 + Δ1, E0′, and E2) has been studied using photoluminescence and UV-Vis ellipsometry methods. By using high activity Ge sources, such as Ge3H8 and Ge4H10, and new-generation doping precursors, including P(GeH3)3, As(GeH3)3, and SbD3, doping levels approaching 1.5 × 1020 cm−3 have been achieved with flat dopant profiles, abrupt n/i interfaces, and close-to-unity dopant activation ratios. The excellent sample quality enabled measurements over sufficiently broad doping ranges to demonstrate, contrary to prior assumptions, that the electronic energy bands do not shift rigidly upon doping and that the different contributions to bandgap renormalization are donor-dependent. It is also shown that simple models of band filling effects provide a quantitative explanation of the doping dependence of critical point parameters such as amplitudes and phase angles. The analysis presented here yields new insights into the physics of highly-doped semiconductor and should facilitate the design of novel Ge-based group-IV microelectronic and photoelectronic devices.
A model for meme popularity growth in social networking systems based on biological principle and human interest dynamics
Authors: Wang Le-Zhi , Zhao Zhi-Dan , Jiang Junjie , Guo Bing-Hui , Wang Xiao , Huang Zi-Gang , Lai Ying-Cheng
Published: February 2019

We analyze five big data sets from a variety of online social networking (OSN) systems and find that the growth dynamics of meme popularity exhibit characteristically different behaviors. For example, there is linear growth associated with online recommendation and sharing platforms, a plateaued (or an “S”-shape) type of growth behavior in a web service devoted to helping users to collect bookmarks, and an exponential increase on the largest and most popular microblogging website in China. Does a universal mechanism with a common set of dynamical rules exist, which can explain these empirically observed, distinct growth behaviors? We provide an affirmative answer in this paper. In particular, inspired by biomimicry to take advantage of cell population growth dynamics in microbial ecology, we construct a base growth model for meme popularity in OSNs. We then take into account human factors by incorporating a general model of human interest dynamics into the base model. The final hybrid model contains a small number of free parameters that can be estimated purely from data. We demonstrate that our model is universal in the sense that, with a few parameters estimated from data, it can successfully predict the distinct meme growth dynamics. Our study represents a successful effort to exploit principles in biology to understand online social behaviors by incorporating the traditional microbial growth model into meme popularity. Our model can be used to gain insights into critical issues such as classification, robustness, optimization, and control of OSN systems.
Impact of non-Maxwellian electron velocity distribution functions on inferred plasma parameters in collective Thomson scattering
Authors: Milder A. L. , Ivancic S. T. , Palastro J. P. , Froula D. H.
Published: February 2019

Optical collective Thomson scattering provides precise density and temperature measurements in numerous plasma-physics experiments. The accuracy of such measurements depends on the core assumption that the underlying electron distribution functions in under-dense laser-produced plasmas are Maxwellian. A statistically based, quantitative analysis of the errors in the measured electron density and temperature is presented when synthetic data calculated using a non-Maxwellian electron distribution function is fit assuming a Maxwellian electron distribution. Such analysis can lead to errors of up to 50% in temperature and 30% in density, in the specific case of super-Gaussian distributions characteristic of inverse bremsstrahlung heating. Including the proper family of non-Maxwellian electron distribution functions, as a fitting parameter, in Thomson-scattering analysis removes the model-dependent errors in the inferred parameters at a minimal cost to the statistical uncertainty.
Conductivity relaxation and photocurrent generation in reduced graphene oxide-poly(9,9′-dioctyl-fluorene-co-bithiophene) composite with application in temperature sensing
Authors: Das Poulomi , Chakraborty Koushik , Pan Arvind , Ghosh Surajit , Pal Tanusri
Published: February 2019

The electrical transport properties and photocurrent generation in a reduced graphene oxide-poly(9,9′-dioctyl-fluorene-co-bithiophene) (RGO-F8T2) composite were investigated. The semiconducting nature of the RGO-F8T2 composite was jointly demonstrated by dc and ac conductivity measurements. The dc conductivity obtained from both dc and ac measurements follows the Arrhenius relationship with the activation energy of the order of 80 meV. The RGO-F8T2 composite also showed excellent temperature sensing properties. The temperature coefficient of resistance was compared to commercially available Platinum, Polysilicon, and Germanium temperature sensor. The conductivity relaxation mechanism in the RGO-F8T2 composite depicted the mechanism behind ac conduction. This was due to phonon assisted tunneling between the defect states. The density of states at the Fermi level increases by one order of magnitude for the temperature change of 301 to 433 K. The scaling of conductivity isotherms established the occurrence of intramolecular energy transfer from disordered to ordered chain segments or both in the composite. The photocurrent generation in the RGO-F8T2 composite thin film under simulated solar light illumination was also studied. Here, a linear variation of the photosensitivity with the variation of the incident light intensity was observed.
Genome-wide association analysis of 1-octen-3-ol content related to soymilk off-flavor in soybean seed
Authors: Xia Ning , Yang Mingming , Zhao Junhan , Shao Yupeng , Shi Yanguo , Yan Wenbing , Wang Xiaoqi , Han Yingpeng , Wang Zhikun
Published: February 2019

Chemical compounds in soybean (Glycine max (L.) Merr.) seed have great effects on the flavour and taste of soymilk. The 1-octen-3-ol content in soybean seed could produce sensory off-flavours (mushrooms, lavender, rose and hay flavour) during the processing of soymilk. The most effective way to reduce off-flavours of soymilk is the screening and utilisation of soybean cultivars with reduced 1-octen-3-ol content. However, genomic study of 1-octen-3-ol in soybean has not previously been reported. In the present work, a natural population of 90 diverse soybean accessions was used to dissect the genetic basis of 1-octen-3-ol content in soybean seed through genome-wide association analysis by using 26822 single nucleotide polymorphisms (SNPs). Twenty-one novel quantitative trait nucleotides (QTNs) were thus identified to be associated with 1-octen-3-ol content in soybean seed. Among them, 13 QTNs overlapped with, or were located in, the linked regions of known QTNs for protein, oil and/or fatty acid content in soybean seed. The functional genes located in the 200-kb genomic region of each peak SNP were considered possible candidates related to 1-octen-3-ol, such as genes involved in amino acid metabolism, protein content, and hormone metabolism. The identified loci with beneficial alleles and the candidate genes may be valuable for improving the off-flavours of soymilk.
Performance and weed-suppressive potential of selected pasture legumes against annual weeds in south-eastern Australia
Authors: Latif Sajid , Gurusinghe Saliya , Weston Paul A. , Brown William B. , Quinn Jane C. , Piltz John W. , Weston Leslie A.
Published: February 2019

Mixed farming systems have traditionally incorporated subterranean clover (Trifolium subterraneum L.) and lucerne (Medicago sativa L.) as key components of the pasture phase across south-eastern Australia. However, poor adaptation of subterranean clover to acidic soils, insufficient and inconsistent rainfall, high input costs, soil acidification and the emergence of herbicide-resistant weeds have reduced efficacy of some traditional clover species in recent years. To overcome these challenges, numerous novel pasture species have been selectively improved and released for establishment in Australia. Despite their suitability to Australian climate and soils, limited knowledge exists regarding their weed-suppressive ability in relation to establishment and regeneration. Field trials were therefore conducted over 3 years in New South Wales to evaluate the suppressive potential of selected pasture legume species and cultivars as monocultures and in mixed stands against dominant annual pasture weeds. Pasture and weed biomass varied significantly between pasture species when sown as monocultures, but mixtures of several species did not differ with regard to establishment and subsequent weed infestation. Arrowleaf clover (T. vesiculosum Savi.) and biserrula (Biserrula pelecinus L.) cv. Casbah showed improved stand establishment, with higher biomass and reduced weed infestation compared with other pasture species. Generally, weed suppression was positively correlated with pasture biomass; however, yellow serradella (Ornithopus compressus L.) cv. Santorini exhibited greater weed suppression than other pasture legumes while producing lower biomass, thereby suggesting a mechanism other than competition for resources affecting weed-suppressive ability. Over the period 2015–17, arrowleaf clover and biserrula cv. Casbah were generally the most consistent annual pasture legumes with respect to yearly regeneration and suppression of annual pasture weed species.
Heterologous expression of rice RNA-binding glycine-rich (RBG) gene OsRBGD3 in transgenic Arabidopsis thaliana confers cold stress tolerance
Authors: Lenka Sangram K. , Singh Amit K. , Muthusamy Senthilkumar K. , Smita Shuchi , Chinnusamy Viswanathan , Bansal Kailash C.
Published: February 2019

Imparting cold stress tolerance to crops is a major challenge in subtropical agriculture. New genes conferring cold tolerance needs to be identified and characterised for sustainable crop production in low-temperature stress affected areas. Here we report functional characterisation of OsRBGD3, classified previously as a class D glycine-rich RNA recognition motif (RRM) containing proteins from a drought-tolerant Indica rice cultivar N22. The gene was isolated by screening yeast one-hybrid library using the minimal promoter region of the OsMYB38 that is necessary for cold stress-responsive expression. OsRBGD3 exhibited cold, drought and salt stress inductive expression in a drought tolerant N22 rice cultivar as compared with susceptible variety IR64. OsRBGD3 was found to be localised to both nuclear and cytoplasmic subcellular destinations. Constitutive overexpression of the OsRBGD3 in transgenic Arabidopsis conferred tolerance to cold stress. ABA sensitivity was also observed in transgenic lines suggesting the regulatory role of this gene in the ABA signalling pathway. OsRBGD3 overexpression also attributed to significant root development and early flowering in transgenics. Hence, OsRBGD3 could be an important target for developing cold tolerant early flowering rice and other crops’ genotypes for increasing production in low temperature affected areas.
Functional study of Csrbohs in defence response against Xanthomonas citri ssp. citri
Authors: Mei Pengying , Song Zhen , Li Zhong'an , Zhou Changyong
Published: February 2019

NADPH oxidases, encoded by rbohs (respiratory burst oxidase homologues), transfer electrons from NADPH to molecular oxygen (O2) to generate superoxide anion (O2•–), which is the first step in the formation of hydrogen peroxide (H2O2) in the plant–pathogen interaction system. In the present work, six citrus rbohs (Csrbohs) genes were identified in citrus, and their possible involvement in resistance to Xanthomonas citri ssp. citri (Xcc) was examined. Inoculation with Xcc promoted the H2O2 production and induced expression of the Csrbohs, especially CsrbohD. Results showed that CsrbohD was markedly induced in the resistant genotype kumquat ‘Luofu’ [Fortunella margarita (Lour.) Swingle] compared with grapefruit ‘Duncan’ [Citrus paradisi (Linn.) Macf.]. Virus-induced gene silencing (VIGS) of CsrbohD resulted in reduced resistance to Xcc in grapefruit, but not in kumquat. Compared with non-silenced plants, canker-like symptoms were observed earlier, and they were more extensive in the CsrbohD-silenced grapefruit. Silencing of CsrbohD also suppressed the Xcc induced reactive oxygen species (ROS) burst, and resulted in accumulation of more Xcc bacterial colonies. Taken together, these data indicate that CsrbohD promotes resistance to Xcc, especially in grapefruit.
Spatial and temporal patterns of reptile roadkill in the north-west Australian tropics
Authors: Hastings Holly , Barr James , Bateman Philip W.
Published: February 2019

Roads present unavoidable challenges to wildlife, both in populated and in more remote regions. Both traffic infrastructure and road vehicles can have a detrimental impact on natural ecosystems and wildlife populations. This study aimed to gain a broad overview of the impacts of a stretch of road on native herpetofauna in north-western Australia. Reptile roadkill was surveyed along a 31-km stretch of the main road in Broome, Western Australia for eight months, during both the wet and dry seasons. There was a significantly higher rate of road mortality in the wet season despite a decrease in traffic intensity. Incidence of roadkill varied between reptile clades, with varanids being the mostly frequently recorded as roadkill. Carcass persistence experiments, however, highlighted a potential significant underestimation in roadkill due to an extremely high rate of carcass removal, emphasising the need to consider this variable when using roadkill as a survey method. We recommend that carcass persistence should be further investigated in order to accurately assess extent of reptile roadkill in the region, and how roads and traffic may impact at-risk species and populations.