bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical physics perspective of fracture in brittle and quasi-brittle materials
Authors: Ray Purusattam 
Published: November 2018

We discuss the physics of fracture in terms of the statistical physics associated with the failure of elastic media under applied stresses in presence of quenched disorder. We show that the development and the propagation of fracture are largely determined by the strength of the disorder and the stress field around them. Disorder acts as nucleation centres for fracture. We discuss Griffith's law for a single crack-like defect as a source for fracture nucleation and subsequently consider two situations: (i) low disorder concentration of the defects, where the failure is determined by the extreme value statistics of the most vulnerable defect (nucleation regime) and (ii) high disorder concentration of the defects, where the scaling theory near percolation transition is applicable. In this regime, the development of fracture takes place through avalanches of a large number of tiny microfractures with universal statistical features. We discuss the transition from brittle to quasi-brittle behaviour of fracture with the strength of disorder in the mean-field fibre bundle model. We also discuss how the nucleation or percolation mode of growth of fracture depends on the stress distribution range around a defect. We discuss the corresponding numerical simulation results on random resistor and spring networks.
This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’.
Statistical physics of fracture and earthquakes
Authors: Biswas Soumyajyoti , Goehring Lucas , Chakrabarti Bikas K. 
Published: November 2018

Manifestations of emergent properties in stressed disordered materials are often the result of an interplay between strong perturbations in the stress field around defects. The collective response of a long-ranged correlated multi-component system is an ideal playing field for statistical physics. Hence, many aspects of such collective responses in widely spread length and energy scales can be addressed by the tools of statistical physics. In this theme issue, some of these aspects are treated from various angles of experiments, simulations and analytical methods, and connected together by their common base of complex-system dynamics.This article is part of the theme issue ‘Statistical physics of fracture and earthquakes’ .
MORPhA Scale: behavioral and electroencephalographic validation of a rodent anesthesia scale
Authors: Esteves Madalena , Almeida António M , Silva Joana , Moreira Pedro Silva , Carvalho Emanuel , Pêgo José Miguel , Almeida Armando , Sotiropoulos Ioannis , Sousa Nuno , Leite-Almeida Hugo 
Published: November 2018

AbstractDegree of anesthesia in laboratory rodents is normally evaluated by testing loss of reflexes. While these are useful endpoint assessments, they are of limited application to study induction/reversal kinetics or factors affecting individual susceptibility (e.g. sex or age). We developed and validated a grading system for a temporal follow up of anesthesia. The Minho Objective Rodent Phenotypical Anesthesia (MORPhA) scale was tested in mice and rats anaesthetized with a mixture of ketamine/dexmedetomidine (ket/dex - 3 doses). The scale comprises 12 behavioral readouts organized in 5 stages – (i) normal/(ii) hindered voluntary movement, elicited response to (iii) non-noxious/(iv) noxious stimuli and (v) absence of response – evaluated at regular time points. Progression across stages was monitored by electroencephalography (EEG) in rats during anesthesia induction and reversal (atipamezole) and during induction with a second anesthetic drug (pentobarbital). Higher anesthetic doses decreased the time to reach higher levels of anesthesia during progression, while increasing the time to regain waking behavior during reversal, in mice and in rats. A regular decrease in high frequencies (low and high gamma) power was observed as the MORPhA score increased during anesthesia induction, while the opposite pattern was observed during emergence from anesthesia through reversion of dex effect. The devised anesthetic scale is of simple application and provides a semi-quantifiable readout of anesthesia induction/reversal.
Risks in signal processing pipelines influencing the estimation of phase dependency for EEG-TMS
Authors: Guggenberger Robert , Scherer Maximilian , Gharabaghi Alireza 
Published: November 2018

AbstractPhase-dependency of cortico-spinal excitability can be researched using TMS-EEG. Due to the large artifact, non-causal filters can smear the TMS artifact and distort the phase. However, causal filters can become biased by too high filter orders or uneven pass-bands. We explored the influence of different signal processing pipelines on the estimation of the optimal phase. This exploration involved performing two simulation studies. In the first, we simulated two different phase-dependencies (uni-versus bimodal) and sought to recover them with two distinct approaches that have previously been described. In the second, we specifically explored how filter parameters (e.g., order, pass-band) biased the phase estimation. On the basis of these findings, we propose using up-to-date toolboxes, re-running scripts after software updates and performing simulation studies in parallel to safeguard the analysis pipeline of empirical studies.
Olanzapine: a full and potent agonist at the hM4D(Gi) DREADD amenable to clinical translation of chemogenetics
Authors: Weston Mikail , Kaserer Teresa , Carpenter Jenna C , Snowball Albert , Knauss Samuel , Lignani Gabriele , Schorge Stephanie , Kullmann Dimitri M , Lieb Andreas 
Published: November 2018

AbstractDesigner receptors exclusively activated by designer drugs (DREADDs) derived from muscarinic receptors are a powerful tool to test causality in basic neuroscience, but are also potentially amenable to clinical translation. A major obstacle is however that the widely-used agonist clozapine-N-oxide undergoes conversion to clozapine, which penetrates the blood-brain barrier but has an unfavorable side effect profile. Perlapine has been reported to activate DREADDs at nanomolar concentrations, but is not approved for use in humans by the Food and Drug Administration or European Medicines Agency, limiting its translational potential. Here we report that the atypical antipsychotic drug olanzapine, widely available in various formulations, is a full and potent agonist of the human muscarinic-receptor M4-based DREADD, facilitating clinical translation of chemogenetics to treat CNS diseases.
Strong preference for autaptic self-connectivity of neocortical PV interneurons entrains them to γ-oscillations
Authors: Deleuze Charlotte , Bhumbra Gary S. , Pazienti Antonio , Mailhes Caroline , Aguirre Andrea , Beato Marco , Bacci Alberto 
Published: November 2018

SummaryParvalbumin (PV) positive interneurons modulate cortical activity through highly specialized connectivity patterns onto excitatory pyramidal neurons (PNs) and other inhibitory cells. PV cells are auto-connected through powerful autapses, but the contribution of this form of fast disinhibition to cortical function is unknown. We found that autaptic transmission represents the most powerful input of PV cells in neocortical Layer V. Autaptic strength was greater than synaptic strength onto PNs as result of a larger quantal size, whereas autaptic and heterosynaptic PV-PV synapses differed in the number of release sites. Overall, single-axon autaptic transmission contributed to ~40% of the total perisomatic inhibition that PV interneurons received. The strength of autaptic transmission modulated the coupling of PV-cell firing with optogenetically-induced γ-oscillations preventing high frequency bursts of spikes. Autaptic self-inhibition represents an exceptionally large and fast disinhibitory mechanism to synchronize the output of PV cells during cognitive-relevant cortical network activity.
Multi-color single molecule imaging uncovers extensive heterogeneity in mRNA decoding
Authors: Boersma Sanne , Khuperkar Deepak , Verhagen Bram M.P. , Sonneveld Stijn , Grimm Jonathan B. , Lavis Luke D. , Tanenbaum Marvin E. 
Published: November 2018

AbstractmRNA translation is a key step in decoding genetic information. Genetic decoding is surprisingly heterogeneous, as multiple distinct polypeptides can be synthesized from a single mRNA sequence. To study translational heterogeneity, we developed the MoonTag, a new fluorescence labeling system to visualize translation of single mRNAs. When combined with the orthogonal SunTag system, the MoonTag enables dual readouts of translation, greatly expanding the possibilities to interrogate complex translational heterogeneity. By placing MoonTag and SunTag sequences in different translation reading frames, each driven by distinct translation start sites, start site selection of individual ribosomes can be visualized in real-time. We find that start site selection is largely stochastic, but that the probability of using a particular start site differs among mRNA molecules, and can be dynamically regulated over time. Together, this study provides key insights into translation start site selection heterogeneity, and provides a powerful toolbox to visualize complex translation dynamics.
In vivo generation of post-infarct mouse cardiac muscle by cardiomyocyte progenitors produced with a reproducible laminin-promoted human stem cell differentiation system
Authors: Yap Lynn , Wang Jiong-Wei , Moreno-Moral Aida , Chong Li Yen , Sun Yi , Harmston Nathan , Wang Xiaoyuan , Chong Suet Yen , Öhman Miina K. , Wei Heming , Bunte Ralph , Gosh Sujoy , Cook Stuart , Hovatta Outi , Kleijn Dominique P.V. de , Petretto Enrico , Tryggvason Karl 
Published: November 2018

ABSTRACTRegeneration of human heart muscle after injury is extremely limited and an unmet clinical need. Despite extensive research, there are no methods for the reproducible generation of clinical quality stem-cell-derived cardiovascular progenitors (CVPs). Here, we identified laminin-221 (LN-221) as the main cardiac laminin, which was produced here as human recombinant protein, and showed that LN-221 promotes differentiation of pluripotent hESCs towards cardiomyocyte lineage and downregulates genes associated with pluripotency and teratoma development. We developed a chemically defined, xeno-free laminin-based cardiomyocyte differentiation protocol to reproducibly generate CVPs that form human muscle in vivo. We assessed the reproducibility of the differentiation protocol using time-course bulk RNA sequencing developed from two different hESC lines. Single-cell RNA sequencing of CVPs derived from two hESC lines further showed high reproducibility and identified three main progenitor subpopulations. These CVPs were transplanted into myocardial infarction mice, where heart function was measured by echocardiogram and human heart muscle bundle formation was identified histologically. This method may provide clinical quality cells for use in regenerative cardiology.
Psittacid Adenovirus-2 infection in the critically endangered orange-bellied parrot (Neophema chrysogastor): A key threatening process or an example of a host-adapted virus?
Authors: Yang Nian , McLelland Jennifer , McLelland David J. , Clarke Judy , Woolford Lucy , Eden Paul , Phalen David N. 
Published: November 2018

AbstractPsittacid Adenovirus-2 (PsAdv-2) was identified in captive orange-bellied parrots (Neophema chrysogastor) during a multifactorial cluster of mortalities at the Adelaide Zoo, South Australia, and an outbreak of Pseudomonas aeruginosa septicaemia at the Tasmanian Department of Primary Industries, Parks, Water and Environment captive breeding facility, Taroona, Tasmania. This was the first time that an adenovirus had been identified in orange-bellied parrots and is the first report of PsAdv-2 in Australia. To investigate the status of PsAdv-2 in the captive population of orange-bellied parrots, 102 healthy birds from five breeding facilities were examined for the presence of PsAdv-2 DNA in droppings and/or cloacal swabs using a nested polymerase chain reaction assay. Additionally, eight birds released to the wild for the 2016 breeding season were similarly tested when they were recaptured prior to migration to be held in captivity for the winter. PsAdv-2 was identified in all breeding facilities as well as the birds recaptured from the wild. Prevalence of shedding ranged from 29.7 to 76.5%, demonstrating that PsAdv-2 is endemic in the captive population of orange-bellied parrots and that wild parrots may have been exposed to the virus. PsAdv-2 DNA was detected in both cloacal swabs and faeces of the orange-bellied parrots, but testing both samples from the same birds suggested that testing faeces would be more sensitive than cloacal swabs. PsAdv-2 was not found in other psittacine species housed in nearby aviaries at the Adelaide Zoo. The source of the infection in the orange-bellied parrots remains undetermined. In this study, PsAdv-2 prevalence of shedding was higher in adult birds as compared to birds less than one year old. Preliminary data also suggested a correlation between adenovirus shedding prevalence within the breeding collection and chick survival.
Migration of di-(2-ethylhexyl) phthalate from the plastic film into the air and vegetables in the greenhouses
Authors: Fu Xiaowei , Huang Bin 
Published: November 2018

AbstractThe aim of this study was to investigate di-2-ethylhexyl phthalate (DEHP) from plastic film of the greenhouse to the air and the vegetables grown in the greenhouse. This paper presents the migration of di-2-ethylhexyl phthalate (DEHP) by determining the di-2-ethylhexyl phthalate (DEHP) concentration in air and vegetables in greenhouses with the change of temperature in a day and a half year. The determination of di-2-ethylhexyl phthalate (DEHP) content in the air and the vegetables was performed by gas chromatography-mass spectrometry. The results showed that di-2-ethylhexyl phthalate (DEHP) content in the greenhouse air increased with increasing temperature during one day, but di-2-ethylhexyl phthalate (DEHP) content changes in vegetable were different from those in air, and which depends on the exposure time. For the monthly content changes, di-2-ethylhexyl phthalate (DEHP) content in air first increased to a maximum and then decreased with increasing time and temperature. The di-2-ethylhexyl phthalate (DEHP) content changes of six vegetables not only were related with di-2-ethylhexyl phthalate (DEHP) content in air and temperature, but also with varieties of vegetables.
Relaxation method in description of RAM memory cell in RSFQ computer
Authors: Pomorski Krzysztof Dominik , Akaike Hiroyuki , Fujimaki Akira , Rusek Krzysztof 
Published: November 2018

Purpose
The lack of reliable and scalable superconducting random access memory (RAM) cells is the main obstacle for full implementation of superconducting rapid single flux quantum(RSFQ) computers. This work points the methodology and the structures that shall be used in future implementation of RSFQ RAM.

Design/methodology/approach
A new design for RAM using two ferromagnetic strips in proximity to the superconductor in a RSFQ computer is presented (1). The concept of using a RAM RSFQ cell as a tuneable superconducting qubit is also explored.

Findings
Two basic architectures for superconducting RAM cells were developed with integration schemes in two dimensions.

Research limitations/implications
The proposed RAM cells as depicted in Figures 7 and 16 offer smaller size and greater 3 scalability in comparison to other suggested schemes (4), (3), (2), (5).

Practical implications
Currently, the main obstacle in implementation of RSQF computer is lack of reliable RAM cell. RSQF computer shall have potential to take a large fraction of classical supercomputers, as it consumes much less power.

Social implications
Computation power shall be cheaper when one uses RSQF computers for big data and computational centres. It is a matter of some time.

Originality/value
The publication presents the new design of superconducting RAM cell for use in RSQF computer. The numerical relaxation method is used to solve biharmonic Ginzburg–Landau equation. The analytic approach as a solution of a specified problem is given.
Understanding internationalisation approaches and mechanisms of diaspora entrepreneurs in emerging economies as a learning process
Authors: Ekanem Ignatius 
Published: November 2018

Purpose
The purpose of this paper is to present an exploration into the internationalisation approaches and mechanisms of diaspora entrepreneurs in emerging economies. It seeks to conceptualise the strategies as a learning process.

Design/methodology/approach
The research is qualitative using a case study approach involving in-depth semi-structured interviews conducted longitudinally.

Findings
The findings suggest that diaspora entrepreneurs adopt mostly the network or, in some cases, the international new venture (born-global) market entry approach rather than the traditional stage by stage approach. The findings also suggest that diaspora entrepreneurs have perceived advantages over domestic small- and medium-sized enterprises (SMEs) because of their foreign exposure which has influenced their entrepreneurial behaviour in exploiting business opportunities.

Practical implications
The main implication of the study is that entrepreneurs who are beginning to internationalise their activities should seek to exploit potential first-mover advantages in emerging economies by realising an approach of internationalisation at high speed.

Originality/value
The paper contributes to better understanding of the diaspora entrepreneurship and its dynamics.
Preparation and tribological properties of a microemulsion for magnesium alloy warm rolling
Authors: Dong Chang , Sun Jianlin , Cheng Zixuan , Hou Yuqing 
Published: November 2018

Purpose
The purpose of this paper is to synthesize a microemulsion and investigate its tribological properties as lubricant. Magnesium alloy warm rolling experiments were conducted. Surface morphology was observed and wear form was summarized. The composition of surface residues was analyzed, which sheds light on the lubrication mechanism of microemulsion.

Design/methodology/approach
A microemulsion was prepared with a proper amount of oil, surfactant, cosurfactant, water and other additives for magnesium alloy strip warm rolling. Tribological properties, such as maximum non-seizure load (PB), friction coefficient (μ) and wear scar diameter (D) of the microemulsion were measured and compared with those of emulsion and rolling oil on an MR-10A four-ball tribotester. The extreme pressure anti-wear coefficients (O) were calculated and compared. Warm rolling experiments were carried out on a Ф 170/400 × 300 mm four-high rolling mill at 240°C to compare the finish rolling thickness and surface quality of rolled AZ31B magnesium alloy strip under four lubrication states, namely, no lubrication, rolling oil, microemulsion and emulsion. The surface morphology after warm rolling was observed with confocal laser scanning microscope and scanning electron microscope, respectively. The composition of surface residues was analyzed with energy dispersive spectrometry and X-Ray photoelectron spectroscopy.

Findings
Surface morphology indicated that pitting wear, adhesive wear and ploughing wear were three main forms of wear in magnesium alloy warm rolling. Microemulsion had excellent lubrication properties with less residual oil remaining. Two types of adsorption layers formed on magnesium alloy strip surface were responsible for lubrication properties. MgSO4 and magnesium stearate in the reaction layer played a key role in anti-wear and friction-reduction in warm rolling.

Originality/value
The study is original and gives valuable information on lubrication mechanism of microemulsion in warm rolling of magnesium alloy strips.
Friction reduction in EHL contacts by surface microtexturing – tribological performance, manufacturing and tailored design
Authors: Tremmel Stephan , Marian Max , Zahner Michael , Wartzack Sandro , Merklein Marion 
Published: November 2018

Purpose
This paper aims to derive tailor-made microtextures for elastohydrodynamically lubricated (EHL) contacts under consideration of manufacturing possibilities.

Design/methodology/approach
Component tests were used for the evaluation of the influence of surface texturing on the friction behavior in the cam/tappet contact. Furthermore, the manufacturing possibilities and limitations of a combined μEDM and micro-coining process and the feasibility of integration into a forming process were studied. Finally, a methodology based on transient EHL simulations and a meta-model of optimal prognosis was exemplarily used for microtexture optimization.

Findings
It was found that surface texturing in EHL contacts with high amount of sliding is promising. Moreover, the combination of μEDM and micro coining and the integration into established production processes allow the manufacturing of microtextures with desirable structural parameters and sufficient accuracy.

Originality/value
This paper gives a holistic view on surface microtexturing over several phases of the product life cycle, from the design, over efficient manufacturing to application-related testing.
Analysis of misaligned water-lubricated polymer bearing with axial grooves
Authors: Lv Fangrui , Jiao Chunxiao , Zou Donglin , Ta Na , Rao Zhu-shi 
Published: November 2018

Purpose
The purpose of this paper is to analyze the lubrication behavior of misaligned water-lubricated polymer bearings with axial grooves.

Design/methodology/approach
A lubrication model considering journal misalignment, bush deformation and grooves is established. In dynamic analyses of shaft systems, bearings are usually simplified as supporting points. Thus, an approach for solving the equivalent supporting point location is presented. The influence of misalignment angle and groove number on film thickness, hydrodynamic pressure distribution, load-carrying capacity and ESP location is investigated.

Findings
As the misalignment angle increases, the location of the maximum pressure and ESP are shifted toward the down-warping end, and the load-carrying capacity of the bearing decreases. In comparison to the nine-groove bearing, the six grooves bearing has a higher load-carrying capacity and the ESP is located closer to the down-warping end for an equivalent misalignment angle.

Practical implications
The results of this study can be applied to marine propeller shaft systems and other systems with misaligned bearings.

Originality/value
A study on the lubrication behavior of misaligned water-lubricated polymer bearings with axial grooves is of significant interest to the research community.