bluuebunny/crossref_metadata_2025_split huggingface dataset:
A compartmentalized, self-extinguishing signaling network mediates crossover control in meiosis
Authors: Zhang Liangyu , Köhler Simone , Rillo-Bohn Regina , Dernburg Abby F. 
Published: July 2017

AbstractMeiotic recombination between homologous chromosomes is tightly regulated to ensure proper chromosome segregation. Each chromosome pair typically undergoes at least one crossover event (crossover assurance) but these exchanges are also strictly limited in number and widely spaced along chromosomes (crossover interference). This has implied the existence of chromosome-wide signals that regulate crossovers, but their molecular basis remains mysterious. Here we characterize a family of four related RING finger proteins inC. elegans. These proteins are recruited to the synaptonemal complex between paired homologs, where they act as two heterodimeric complexes, likely as E3 ubiquitin ligases. Genetic and cytological analysis reveals that they act with additional components to create a self-extinguishing circuit that controls crossover designation and maturation. These proteins also act at the top of a hierarchical chromosome remodeling process that enables crossovers to direct stepwise segregation. Work in diverse phyla indicates that related mechanisms mediate crossover control across eukaryotes.
Avoidance of toxic misfolding and protein stability do not explain the sequence constraints of highly expressed proteins
Authors: Plata Germán , Vitkup Dennis 
Published: July 2017

AbstractThe avoidance of cytotoxic effects associated with protein misfolding has been proposed as a dominant constraint on the sequence evolution and molecular clock of highly expressed proteins. Recently, Leuenbergeret al.developed an elegant experimental approach to measure protein thermal stability at the proteome scale. The collected data allow us to rigorously test the predictions of the misfolding avoidance hypothesis that highly expressed proteins have evolved to be more stable, and that maintaining thermodynamic stability significantly constrains their evolution. Notably, careful re-analysis of the Leuenbergeret al.data across four different organisms reveals no substantial correlation between protein stability and protein abundance. Therefore, the key predictions of the misfolding toxicity and related hypotheses are not supported by available empirical data. The data also suggest that, regardless of protein expression, protein stability does not substantially affect the protein molecular clock across organisms.
Polar-angle representation of saccadic eye movements in human superior colliculus
Authors: Savjani Ricky R , Halfen Elizabeth , Kim Jung Hwan , Ress David 
Published: July 2017

SummaryThe superior colliculus (SC) is a layered midbrain structure involved in directing eye movements and coordinating visual attention. Electrical stimulation and neuronal recordings in the intermediate layers of monkey SC have shown a retinotopic organization for the mediation of saccadic eye-movements. However, in human SC the topography of saccades is unknown. Here, a novel experimental paradigm and highresolution (1.2-mm) functional magnetic resonance imaging methods were used to measure activity evoked by saccadic eye movements within SC. Results provide three critical observations about the topography of the human SC: (1) saccades along the superior-inferior visual axis are mapped across the medial-lateral anatomy of the SC; (2) the saccadic eye-movement representation is in register with the retinotopic organization of visual stimulation; and (3) activity evoked by saccades occurs deeper within SC than that evoked by visual stimulation. These approaches lay the foundation for studying the organization of human subcortical eye-movement mechanisms.HighlightsHigh-resolution functional MRI enabled imaging from intermediate layers of human SCSaccades along superior-inferior visual field are mapped across medial-lateral SCSaccadic eye movement maps lie deeper in SC and are in alignment with retinotopyeTOC BlurbSavjani et al. found the polar angle representation of saccadic eye movements in human SC. The topography is similar in monkey SC, is in register with the retinotopic organization evoked by visual stimulation, but lies within deeper layers. These methods enable investigation of human subcortical eye-movement organization and visual function.
The impact of flipped classroom in MBA’s evaluation
Authors: Scafuto Isabel , Serra Fernando , Mangini Eduardo , Maccari Emerson Antonio , Ruas Roberto 
Published: July 2017

Purpose
The purpose of this paper is to evaluate the perceived quality of the service environment, regarding the use of the flipped classroom, through a survey of MBA students.

Design/methodology/approach
Four hypotheses were developed from the literature in marketing and quality services in higher education. The hypotheses were tested using linear regressions. The data were collected using a structured questionnaire. The sample had 981 effective responses.

Findings
The results of the statistical analysis show that the evaluation of the perceived quality of the educator and course are positively affected by the use of the flipped classroom.

Research limitations/implications
Only one higher education organisation was studied. The variables analysed have no mediation and moderation, which is a suggestion for future studies.

Originality/value
This paper contributes to studies of higher education services and quality, as it shows the influence of the process on the educator. In higher education, the educator is usually considered independent, having a strong influence on perceived quality. The study contributes to the theme by showing the flipped classroom as an effective teaching strategy that requires further empirical study.
The soot handling ability requirements and how to solve soot related viscosity increases of heavy duty diesel engine oil
Authors: Tang Zhongping , Feng Zhengwen , Jin Peng , Fu Xisheng , Chen Hua 
Published: July 2017

Purpose
The purpose of this paper is to identify the feature of soot in diesel engine oil and provide a method to stably disperse these soots using effect additives which is benefical for lubricants to pass related engine tests.

Design/methodology/approach
This paper designed experiments to investigate the dispersant type, treat level and different dispersant interactions which influence on lubricant soot-related viscosity increase. The research work developed an effective dispersant package which can well solve the soot-related viscosity increase, allowing pass Mack T-11 and Mack T-8 engine tests and demonstrated the helpfulness of using a quickly screening method developed by a steel piston diesel engine CA 6DL2-35.

Findings
The effect of dispersant treat level on the viscosity increase of the oil samples was negligible. Dispersant booster can effectively improve the soot handling ability of heavy-duty diesel engine oils (HDDEO), and the appropriate treat level of dispersant booster can help HDDEO pass Mack T-8 and Mack T-11 engine tests.

Practical implications
The test results are useful for formulators to select the appropriate dispersants or dispersant booster to develop the HDDEO packages which can meet the modern diesel engine lubrication requirements.

Originality/value
Most previous studies in this field were carried out on soot formation mechanism and soot-related wear rather than how to solve the soot-related viscosity increasing of HDDEO. This paper describes the soot dispersing requirements of different HDDEO specifications and developed an effective dispersant package which can well deal with Mack T-11 and Mack T-8E standard engine tests soot handling ability requirements.
Preparation and performance evaluation of mPAO8 using olefin from coal as raw material
Authors: Ma Yuefeng , Xu Jian , Zeng Xiangqiong , Jiang Haizhen , Li Jiusheng 
Published: July 2017

Purpose
The purpose of this paper is to prepare metallocene polyalphaolefin 8 (mPAO8) by the oligomerization of olefin from coal with metallocene catalyst system and compare it with commercially available polyalphaolefin 8 (PAO8) from Chevron.

Design/methodology/approach
Molecular structures, component and mass were determined by nuclear magnetic resonance spectroscopy, gas chromatography and gel permeation chromatography, respectively. The physico-chemical properties, including Noack volatility, viscosity index and elemental analyses, were studied. The oxidative stability was evaluated by pressurized differential scanning calorimetry, whereas the thermal stability was studied by thermo-gravimetric analysis.

Findings
The produced mPAO8 consisted of a large part of tetramer, pentamer and a small part of trimer and hexamer. Additive T501 significantly improved the oxidation stability of PAO8 from Chevron and the synthesized mPAO8. Both samples had similar properties, such as oxidative stability, additive response, pour point and Noack volatility loss. But mPAO8 possessed a higher thermal stability, better viscosity index and flash point than PAO8. Therefore, the mPAO8 prepared by the oligomerization of olefin from coal could be used as base oil for lubricant development.

Originality/value
The mPAO8 base oil was successfully prepared by successive carbon numbers and shows similar properties with commercially available PAO8 products from Chevron. The findings can cover the shortage of the synthesis lubricants market in China.
Experimental and numerical investigation on single dent with marginal bump in EHL point contacts
Authors: Wang Xue-feng , Hu R.F. , Shang Weiyan , Zhao Fuzhou 
Published: July 2017

Purpose
The dent is one of typical surface defects on the surfaces of the machine elements and it is not in fact inerratic. This work aims to investigate the effect of a single dent with a marginal bump on the film shape in elastohydrodynamic lubrication (EHL) point contacts.

Design/methodology/approach
The experimental investigations of a single dent with marginal bump were carried out using multi-beam interferometry in EHL point contacts. In the meantime, its numerical simulation was also finished using multi-level method and multilevel multi-integration method. The effects of the entrainment velocity and the applied load as well as the slide-roll ratio on the film were chiefly discussed. Meanwhile, the comparison of films between smooth and dented surfaces was conducted under simple sliding conditions.

Findings
Under pure sliding conditions, the minimum film thickness presents itself near the marginal bump at lower entrainment velocity. The inlet dimple before the marginal bump is subjected to the operating conditions. Under pure rolling conditions, the shape of the dent is almost unchanged when it is passing through the contact region at lower entrainment velocity. The dent depth hardly depends on the applied load under static conditions. However, larger load enhances the inlet dimple and the elastic deformation of the dent with the marginal bump under pure sliding conditions.

Originality/value
This work is helpful to understanding the effect of the marginal bump before the single dent on point contact EHL films.
Rheological behaviour of lubrication oils used in two-stroke marine engines
Authors: Ravendran Rathesan , Jensen Peter , de Claville Christiansen Jesper , Endelt Benny , Appel Jensen Erik 
Published: July 2017

Purpose
The purpose of this study is to investigate the rheological behaviour of commercial lubrication oils used for cylinder lubrication in two-stroke marine diesel engines. Furthermore, it is of interest to investigate whether the viscosity of lubrication oils is affected by different levels of alkalinity.

Design/methodology/approach
Viscosity measurements are performed using both rotational and capillary rheometry. It was possible to measure oil viscosity in the shear rate from 0.1 to 3,000 s−1 using rotational rheometry, whereas capillary rheometry allowed measurements in higher shear rates from 5 × 105 to 1.3 × 106 s−1 at 50°C.

Findings
The viscosity measurements show that the studied lubrication oils behave as a Newtonian fluid and that the viscosities are insensitive to the level of alkalinity. Furthermore, the viscosity/temperature dependency for the lubrication oils was found to fit the Arrhenius model.

Originality/value
This study presents useful information about the rheological behaviour of lubrication oils, more precisely how the oil properties are affected by shear rate, temperature and level of alkalinity. The value of this research is considered to be important for designing two-stroke diesel engines and cylinder lubrication systems.
Behavior evaluation and effects of different lubricants in ECAP process
Authors: Hasani Najafabadi Seyed Husein , Lotfi Neyestanak Ali Akbar , Daneshmand Saeed 
Published: July 2017

Purpose
The purpose of equal channel angular pressing (ECAP) is producing ultra-fine grain materials. In practical applications, it is important to understand and predict effect of different process parameters on deformed parts. One of the most important process parameters is friction coefficient. Behavior evaluation of different lubricants in the ECAP process is the aim of this research.

Design/methodology/approach
The present study concerns the experimental measurements of the effective strain by means of gridded parts for three different lubricants, graphite, molybdenum disulfide and zinc stearate, to evaluate friction coefficient in ECAP process. Mesh size was 2 × 2 mm2 and embedded in parts made of AL2024; process was done in ambient temperature, and parts were in annealed situation. After the process, strain measured by optical and analytical methods for evaluation of lubricants’ behavior with different friction coefficients.

Findings
This study shows that zinc stearate has better effects rather than other lubricants in ECAP process and ECAPed parts.

Originality/value
The fatal challenge for researchers and industrial applications of ECAP process is lubrication. This research is a guide for scientists and engineers (in the future applications) to reduce and control bad frictional effects, produce better parts (more strain homogenous parts), prevent die failures and decrease press tonnage in ECAP process.
The effect of dimple size on the tribological performances of a laser surface textured palm kernel activated carbon-epoxy composite
Authors: Mohmad Martini , Abdollah Mohd Fadzli Bin , Tamaldin Noreffendy , Amiruddin Hilmi 
Published: July 2017

Purpose
The purpose of this study is to investigate the effect of dimple size on the tribological performances of laser surface-textured palm kernel-activated carbon-epoxy (PKAC-E) composite.

Design/methodology/approach
A PKAC-E disc 74 mm in diameter was fabricated using the hot compression moulding technique. Five different types of surface contacts were prepared using a CO2 laser surface-texturing machine: a non-textured surface, and surfaces with dimples between 500 and 1,200 μm in diameter. The area density, contact ratio and depth were kept constant. A sliding test was carried out using a ball-on-disc tribometer under boundary lubricated conditions with constant sliding speed, sliding distance and applied load.

Findings
In general, the results showed that the friction coefficient decreased with an increasing dimple diameter of surface-textured PKAC-E composite. However, the appropriate dimple diameter for maintaining low friction coefficient is proposed in the range of 800 to 1,000 μm.

Originality/value
This is the first study, to the authors’ knowledge, to investigate the effects of dimple size, which is larger than 500 μm, on the tribological performances of laser surface-textured PKAC-E composite.
Hydrodynamic journal bearing lubricated with a ferrofluid
Authors: Patel Nimeshchandra S. , Vakharia Dipak , Deheri Gunamani 
Published: July 2017

Purpose
This paper aims to investigate the performance of a ferrofluid-based hydrodynamic journal bearing system.

Design/methodology/approach
This paper presents a new design of ferrofluid-based hydrodynamic journal bearing. An experimental set-up consisting of a magnetic shaft along with a brass bearing was modified and developed. A permanent magnet was used to make the selected shaft material magnetic. The load and speed were varied to conduct the analyses for different test conditions.

Findings
The paper provides information about a design of ferrofluid-based journal bearing and its improved performances. For moderate to higher loads at different shaft speeds, it was found that because of the magnetization effect, the maximum film pressure in case of a ferrofluid lubricant increased up to approximately 60 per cent, compared with that of the conventional lubricant-based journal bearing system. Besides, the temperature rise was found smaller for ferrofluid lubricants, thus making the system cooler while running.

Originality/value
This paper offers a new design of magnetic bearing system for the experimental analysis by utilizing a magnetic shaft with a non-magnetic bearing. The present ferrofluid-based bearing design is less complicated from manufacturing point of view.
Quantitative analysis of wear particles generated by cavitation erosion in glycerol-water mixtures
Authors: Saleh Bahaa , Abouel-Kasem A. , Ahmed Shemy 
Published: July 2017

Purpose
This paper aimed to analyze removed particles from stationary specimen-aluminum (Al-99.92) produced by vibratory cavitation erosion tests in distilled water and glycerol-water mixtures.

Design/methodology/approach
The particle morphology which include particle surface topography, size distribution, particle size parameters and particle shape parameters were examined for distilled water and glycerol-water mixtures having different viscosities.

Findings
The results showed that the variation of size parameters with viscosity was very similar to the variation of weight loss with viscosity. Both the size parameters and weight losses show a monotonic decrease in going from distilled water to glycerol-water mixtures having viscosity about 10.1 cSt, beyond which the change is very small. On the other hand, the shape parameters were much less sensitive to distinguish between the particles produced in water and glycerol-water mixtures. The mechanism of cavitation erosion is investigated in detail through observations of the removed particles. The particle surfaces topography demonstrated that the mechanism in water and glycerol-water mixtures was fatigue failure.

Originality/value
Cavitation often occurs in almost all machines that handle liquids, especially at high speeds, leading to irreparable damage of the components of these machines. Elucidation of such complex phenomenon demands full characterization of the erosion mechanism and controlling parameters inherent to it, so that cavitation erosion can be prevented or at least be reduced through adequate information and collection of relevant data under different operating conditions. Very few studies have been made to approach the viscosity effect upon cavitation erosion from the particle analysis standpoint. The aim of the present work is to identify the effect of liquid viscosity on the size, shape characteristics of the erosion particles and their morphological features. The prevailed mechanisms of wear and particle generation have been proposed based on the acquired information from particle analysis.
Differences between perceived usefulness of social media and institutional channels by undergraduate students
Authors: Sumida Garcia Leandro , Costa Silva Camila Mariane 
Published: July 2017

PurposeThis research aims to compare the preference of social media sites and institutional communication channels of a higher education institution by confronting elements that form perceived usefulness and user satisfaction with the system. Social media technologies are a part of the routine of the modern society in many diverse ways, including the support and even substitution of software designed specifically for knowledge acquisition and sharing. If students do not see value in the use of virtual learning environments and learning platforms, such tools might be prone to obsolescence as well.Design/methodology/approachThe study was applied in a Brazilian public university located in a major city near São Paulo. The paper shows the results of the analysis of a survey with 108 answers, testing a model based on the information system success and on the technology acceptance model. The perceived usefulness of information technology is also subject to test through a Studentt-test.FindingsThe paper shows that students perceive more value when using social media technologies to perform academic activities than in information systems provided by the university, mainly owing to the ease of use of the former. Service quality does not present a strong role as an antecedent variable in any case.Practical implicationsStudents do not expect or do not see value in technical support during their general experience or usefulness for any of the analysed technologies. Thus, higher education institutions should focus their initiatives in providing availability, information quality and usability for institutional channels or, if they choose to do so, social media sites as well.Originality/valueThis study contributes to educational institutions by attaining better use of available IT tools for academic purposes. Previous studies looked for monitored or institutionalized use of social media tools in an educational context, but there was no in-depth analysis of spontaneous use by students to perform academic tasks.
Refactoring a CS0 course for engineering students to use active learning
Authors: Lokkila Erno , Kaila Erkki , Lindén Rolf , Laakso Mikko-Jussi , Sutinen Erkki 
Published: July 2017

PurposeThe purpose of this paper was to determine whether applying e-learning material to a course leads to consistently improved student performance.Design/methodology/approachThis paper analyzes grade data from seven instances of the course. The first three instances were performed traditionally. After an intervention, in the form of applying e-learning methodologies, more data were collected from four course instances. These data are then analyzed and compared.FindingsThe main finding of this paper is that the application of e-learning improved the overall grades and decreased the fail rates of students who took this course.Originality/valueThis paper demonstrates the efficacy of applying e-learning methods to an undergraduate course. This paper is of special interest to educators, who wish to improve and enhance their teaching.
An investigation into the Community of Inquiry model in the Malaysian ESL learners’ context
Authors: Annamalai Nagaletchimee 
Published: July 2017

Purpose
This study aims to explore how the Community of Inquiry (CoI) model (2000) is used to categorize students’ and teachers’ interactions in an asynchronous discussion and how these interactions are able to help students add quality to their narrative writing.

Design/methodology/approach
The interactions were categorized based on teaching, social and cognitive presences suggested by the CoI model. Data collection included online archives and students’ narrative essays. Content analysis was performed based on the presences suggested by the CoI model. Scores for the narrative essays were based on Tribble’s (1996) assessment scale.

Findings
The findings indicated that the interactions were significantly related to the cognitive, teaching and social presences. However, the cognitive presence indicated a distinctive pattern. As this was a qualitative study, there were emerging themes. The study found that critical thinking was minimal, as the writing task was related to creative thinking.

Research limitations/implications
It is suggested that writing in the online environment should also consider different types of writing.

Originality/value
The emerging themes can be used to enhance and complement the CoI model when used in the Malaysian setting.