bluuebunny/crossref_metadata_2025 huggingface dataset:
Autonomy, workload, work-life balance and job performance among teachers
Authors: Johari Johanim , Yean Tan Fee , Tjik Zulkarnain Zati Iwani
Published: January 2018

Purpose

The purpose of this paper is to examine the influence of autonomy, workload, and work-life balance on job performance among teachers. A survey was carried out among teachers in public schools in the Northern Region of Peninsular Malaysia.

Design/methodology/approach

This study adopted a quantitative approach to address the research objectives. A total of 302 teachers reported on their level of autonomy, workload, and work-life balance as well as job performance. Data were analyzed using Statistical Package for Social Sciences version 17.0 and Partial Least Square (Smart PLS) version 2.0.

Findings

Based on the statistical analyses conducted, the findings reported that autonomy and work-life balance had a significant impact on respondents’ job performance. Workload, on the other hand, had no substantial bearing on job performance among school teachers in this study.

Practical implications

In terms of practical ramifications, the management of schools need to focus on measures to enhance autonomy and work-life balance in improving job performance among teachers. Finally, directions for future research and conclusion of the study are also presented.

Originality/value

Discussions emphasized on the importance of work-life balance and autonomy in elevating job performance among teachers. This study also provided partial support to the Border and Boundary Theory.
Exploring the effects of authentic leadership on academic optimism and teacher engagement in Thailand
Authors: Kulophas Dhirapat , Hallinger Philip , Ruengtrakul Auyporn , Wongwanich Suwimon
Published: January 2018

Purpose

In the context of Thailand’s progress towards education reform, scholars have identified a lack of effective school-level leadership as an impeding factor. The purpose of this paper is to develop and validate a theoretical model of authentic leadership effects on teacher academic optimism and work engagement. Authentic leadership was considered a suitable model of school leadership in light of Thailand’s explicit recognition of the importance of developing the moral capacity of students and emphasis on ethical leadership.

Design/methodology/approach

The study employed a quantitative cross-sectional survey design. Survey data were obtained from 605 teachers in a nationally representative sample of 182 primary schools. The data were analyzed using confirmatory factor analysis and structural equation modeling.

Findings

The results indicated that the model of authentic leadership effects on teachers’ academic optimism and work engagement was validated. A moderate relationship was observed between authentic leadership and the dependent measures of teacher attitudes.

Practical implications

The study identified a potentially important lack of alignment between the espoused values and actions/decisions of school principals in Thailand. When combined with prior research conducted on leadership for educational reform in Thailand, our findings highlight the systemic nature of the problem faced in changing traditional patterns of behavior in Thai schools. More specifically, despite change in the nation’s educational goals, human resource management of the nation’s school leaders continues to produce administrators and managers rather than leaders, either instructional or moral.

Originality/value

The study extends prior studies of school leadership in the context of Thailand’s education reform that focused more specifically on principal instructional leadership in Thailand. In addition, this study of authentic school leadership is one of only a few conducted outside of Western societies.
Competitiveness vis-à-vis motivation and personality as drivers of academic performance
Authors: Baumann Chris , Harvey Marina
Published: January 2018

Purpose

The purpose of this paper is to build on the foundational theories of personality and motivation to explore the role of competitiveness and of ethnicity in relation to student academic performance. Survey data from 328 students across four sites (Australia, Denmark, Hong Kong and Korea) provided self-rated responses to items measuring personality, motivation, competitiveness and ethnicity.

Design/methodology/approach

Stepwise multiple regression was used to identify the variables that predicated student academic performance, including testing for interaction effect of ethnicity. Both student self-reported data and independently assessed performance measures were used to avoid common method variance.

Findings

This study affirmed that both intrinsic and extrinsic motivation are significantly associated with academic performance. The personality traits of conscientiousness, agreeableness, extraversion and neuroticism are significantly associated with a student’s competitiveness. The interaction of competitiveness and ethnicity is significantly and positively associated with performance.

Research limitations/implications

The variable of student competitiveness requires further research to better understand its role in academic performance. Researching ethnicity at the micro level allows the acknowledgement and investigation of “intra-national diversity” (Tung, 2008; Tung and Baumann, 2009).

Originality/value

This study is original in its approach in that it combines the concepts of motivation, personality, competitiveness and ethnicity in relation to student academic performance. While previous studies have explored these concepts individually and often at the macro level, a crucial contribution of this study is that competitiveness and ethnicity (as opposed to national culture) are examined at a micro level. The authors demonstrate the combined importance of intrinsic and extrinsic motivation (carrot and stick) in driving performance and introduce the new motivation, competitiveness and performance model which recognises that competitiveness, as a driver of performance, is moderated by the learners’ ethnicity.
Library data labs: using an agile approach to develop library analytics in UK higher education
Authors: Burke Siobhán , MacIntyre Ross , Stone Graham
Published: January 2018

Purpose

The purpose of this paper is to give an overview of the Jisc and Higher Education Statistics Agency (HESA) Library Data Labs project and its outputs. This collaboration involved bringing together cross-institutional library teams to produce proof of concept data-visualised dashboards using library analytics data that could be made available to others via the Heidi Plus service.

Design/methodology/approach

The teams used an agile approach, which adapted the agile methodology for non-technical and disparate team members. The key agile elements were followed, including the Scrum approach, whereby teams had a product owner, several development team members, a data wrangler and a scrum master. Many of the dashboards took inspiration from some of the earlier Jisc work on library analytics.

Findings

A wide variety of proof of concept dashboards were created addressing a range of library issues. These fell into two main categories for the cross-institutional teams, namely, comparing the Society of College, National and University Libraries (SCONUL) annual statistics results against the National Student Survey (NSS) data and collection management and analysis.

Research limitations/implications

Some of the HESA data were potentially sensitive. In effect, this created a walled garden as some of the data were not designed for sharing. Furthermore, the data that the Jisc team used were restricted by publisher agreements, meaning that specific institutions’ usage could not be identified to others.

Originality/value

The paper provides insight into the Library Data Labs project and discusses a number of implications from the outcomes of the project. These are now being investigated by HESA, Jisc and individual institutions.
Measuring the academic library
Authors: Salisbury Fiona , Peasley Jennifer
Published: January 2018

Purpose

The purpose of this paper is to provide an Australian perspective of impact and value by examining how the broader international and national perspectives play out in practice in the Australian context and where adaption for local requirements is necessary.

Design/methodology/approach

This paper will explore the assessment of impact and value in academic libraries and the tools available to translate today’s inputs into future impact and value. It will focus on a range of methods and procedures, including international and national standards, frameworks and benchmarks.

Findings

The La Trobe University Library is presented as a case study to examine the challenges of leveraging tools to assess impact and communicate the value of the library across the university community.

Originality/value

Assessing the impact and demonstrating the value of the academic library in a digital environment is a constant challenge. While usage and service data are plentiful, traditional metrics no longer sufficiently demonstrate the academic library’s contribution to university learning, teaching and research outcomes.
The problems and promise of learning analytics for increasing and demonstrating library value and impact
Authors: Oakleaf Megan
Published: January 2018

Purpose

The purpose of this paper is to describe the need for academic libraries to demonstrate and increase their impact of student learning and success. It highlights the data problems present in existing library value correlation research and suggests a pathway to surmounting existing data obstacles. The paper advocates the integration of libraries into institutional learning analytics systems to gain access to more granular student learning and success data. It also suggests using library-infused learning analytics data to discover and act upon new linkages that may reveal library value in an institutional context.

Design/methodology/approach

The paper describes a pattern pervasive in existing academic library value correlation research and identifies major data obstacles to future research in this vein. The paper advocates learning analytics as one route to access more usable and revealing data. It also acknowledges several challenges to the suggested approach.

Findings

This paper describes learning analytics as it may apply to and support correlation research on academic library value. While this paper advocates exploring the integration of library data and institutional data via learning analytics initiatives, it also describes four challenges to this approach including librarian concerns related to the use of individual level data, the tension between claims of correlation and causation in library value research, the need to develop interoperability standards for library data and organizational readiness and learning analytics maturity issues.

Originality/value

This paper outlines a path forward for academic library value research that may otherwise be stymied by existing data difficulties.
Ranking authors in academic social networks: a survey
Authors: Amjad Tehmina , Daud Ali , Aljohani Naif Radi
Published: January 2018

Purpose

This study reviews the methods found in the literature for the ranking of authors, identifies the pros and cons of these methods, discusses and compares these methods. The purpose of this paper is to study is to find the challenges and future directions of ranking of academic objects, especially authors, for future researchers.

Design/methodology/approach

This study reviews the methods found in the literature for the ranking of authors, classifies them into subcategories by studying and analyzing their way of achieving the objectives, discusses and compares them. The data sets used in the literature and the evaluation measures applicable in the domain are also presented.

Findings

The survey identifies the challenges involved in the field of ranking of authors and future directions.

Originality/value

To the best of the knowledge, this is the first survey that studies the author ranking problem in detail and classifies them according to their key functionalities, features and way of achieving the objective according to the requirement of the problem.
Applying social marketing mix to identify consumers’ preferences towards functional dairy products in Iran
Authors: Bazhan Marjan , Kalantari Naser , Keshavarz-Mohammadi Nastaran , Hosseini Hedayat , Eini-Zinab Hassan , Alavi-Majd Hamid
Published: January 2018

Purpose

During the past few decades, production and marketing of functional foods has increased in many countries including Iran. Considering the fact that consumers’ preferences play an important role in the success of marketing a product to increase consumption, this study aims to fill the knowledge gap in this regard in Iran.

Design/methodology/approach

The theory of social marketing served as the framework of this study. Qualitative data were collected via eight semi-structured focus group discussions, between May and September 2014. Participants were 65 women (44 housewives and 21 employed women), aged 23-68 years, selected by purposeful sampling technique, considering maximum diversity. All focus group discussions were audio recorded and transcribed verbatim. Analysis of the qualitative content of the data was conducted using MAXQDA® software.

Findings

The findings showed that there were quite diverse preferences among studied women in regards to different aspects of a product and its social marketing strategies. The preferences toward functional dairy products were categorized in four main groups: characteristics of products including sensory and non-sensory characteristics; price; place of the product supply; and promotion strategies of products categorized in three subgroups of informing and educating, advertising and recommending.

Originality/value

This study is the first study in this regard in Iran. Given the novelty of functional dairy products in the market, the diversity of preferences should be considered both in production of dairy foods and their promotion plans. This understanding can contribute to success of interventions to increase consumption of these products among consumers.
Assessing the prevalence of malnutrition in chronic kidney disease patients undergoing hemodialysis in Kushtia District, Bangladesh
Authors: Reza Hasan Mahfuz , Shuvo Suvasish Das , Ahmad Tanvir
Published: January 2018

Purpose

The purpose of this study is to evaluate the nutritional status of patients with end-stage kidney disease undergoing hemodialysis.

Design/methodology/approach

End-stage renal failure outpatients on hemodialysis were selected using simple random sampling technique from the dialysis unit of Sono Hospital Limited, Kushtia, Bangladesh. The nutritional status of 142 participant, of age 18-65 years, was screened. A direct method of nutritional assessment including anthropometric measurement, biochemical measurement, clinical assessment and dietary method was conducted. A logistic regression was applied to estimate the prevalence of malnutrition in hemodialysis patients.

Findings

In total 69.0 per cent participants were men and 31.0 per cent were women, whereas about 65.5 and 16.9 per cent patients of this study had a BMI of less than 23 kg/m2and 18.5 kg/m2(p< 0.05) where malnutrition was significantly prevalent. Mean ± SD hemoglobin level of both men and women participants was below the normal level which might increase the risk of malnutrition (p< 0.05). Of the total number of participants, 97.2 per cent were anemic, 66.9 per cent had anorexia, 63.4 per cent complained of nausea, 58.5 per cent complained of vomiting and 26.1 per cent complained of diarrhea, factors that can increase the risk of malnutrition in hemodialysis patients (p< 0.05). The creatinine and urea levels were higher in both men and women participants (p< 0.05). Results show significant difference in albumin levels among men and women (p< 0.05). The bicarbonate level was lower in both men and women, and the participants were suffering from metabolic acidosis (p< 0.05). About 87.3 per cent participants were taking inadequate amounts of protein which was a significant risk factor of malnutrition in hemodialysis patients (p< 0.01).

Originality/value

The result shows that renal failure is prevalent more in men than in women. The majority of patients on hemodialysis were at a risk of malnutrition including being underweight. Most of the patients were anemic. Malnutrition is related to low nutrient intake.
A comparative study on registration system of real estate between Hong Kong and Mainland China
Authors: Wang Hao , Wei Shuyan , Tang Bo-sin , Chen Junhua , Li Wenbin
Published: January 2018

Purpose

The purpose of this paper is to review land/real estate registration practice in Hong Kong, and make an in-depth comparison with Mainland China and finally provide helpful suggestions for the government.

Design/methodology/approach

Research methods including document analysis/review and comparative study are used in this paper.

Findings

The main findings focus on the problems existing in the mainland, including narrow query subject, single way of query, limited query time, and lacking of incentive mechanism. Helpful suggestions for real estate registration system in Mainland China are offered based on the comparative study.

Practical implications

The unified registration system can improve the efficiency of administrative institutions to ensure an open and transparent environment of property right registration, which helps prevent the relevant departments from abusing administrative power and harming the interests of obligees. The findings of this research can serve as a useful reference for policy makers to improve the unified registration system in China.

Originality/value

The registration system/mechanism determines the efficiency and effectiveness of real estate/land market. However, land registration and query in some countries such as Mainland China have institutional problems which hinder the sustained and healthy development of the real estate industry. The value of this paper is to propose constructive suggestions for such countries/regions by comparing and learning from a good model.
Assessing determinants of PPP project performance
Authors: Swamy Raghu Rama D.T.V. , Tiwari Piyush , Sawhney Anil
Published: January 2018

Purpose

The purpose of this paper is to understand the factors that affect the performance of projects being implemented on the public-private partnership (PPP) framework, with specific reference to urban drinking water sector in India.

Design/methodology/approach

A listing of factors that have a bearing on project performance have been developed based on a review of the literature. Through a survey, seven factors that are relevant to the Indian context were determined. Interviews were then conducted across a cross-section of government agencies, financial institutions, development agencies, private sector entities and consultants to understand the relative importance of these attributes. The analytical hierarchy process was used to develop relative weights of these factors.

Findings

Ranking and relative weights of the factors in descending order are stakeholder consent and support for water PPP projects (22.1 percent), appropriate project structure (17.4 percent), availability of realistic baseline information (16.2 percent), reasonable water tariffs (13.9 percent), public sector capacity (13.0 percent), well-developed market (9.5 percent) and water sector regulator (7.9 percent). Differences in perceptions amongst various stakeholder groups were also found.

Research limitations/implications

Water sector has not matured, and with the advent of newer formats of implementation models, there could be significant changes in the sector. As the number of projects available for study is limited, this exercise can be undertaken periodically and updated in relation to experiences in other infrastructure sectors.

Practical implications

This analysis provides inputs to policymakers and project proponents for structuring more sustainable urban drinking water PPP projects.

Originality/value

Indian infrastructure PPP market is attracting increased attention from researchers, though not much emphasis is being given to urban drinking water sector. This paper aims to contribute toward filling this research gap.
The Accessibility of People with Disabilities to the Tourism Activities in Batu City
Authors: Arawindha Ucca , Fitrianita Titi
Published: January 2018

This study aims at identifying the accessibility of people with disabilities to the tourism activities in Batu City. Batu is a city whose tourism industry develops so rapidly that it is called A Tourism City. Despite its multiple artificial and natural tourist sites, Batu City does not provide the accessible infrastructure for people with disabilities. According to the Local Regulation Number 7 Year 2011 about The Urban Planning of Batu City Year 2010-2030, the regulation about the disabled-friendly infrastructure is still minimum. It is only stated in Chapter 10 Section (4) m, explaining that the pedestrian lane is equipped with the walking lane for people with disabilities. However, if we refer to the Local Regulation of East Java Province Number 3 Year 2013 about Security and Service for People with Disabilities, every city/district is obliged to provide the accessible infrastructure for people with disabilities, including the accessible infrastructure in the tourist site. The accessibility is not limited to the walking lane for people with disabilities included in the Local Regulation of Batu City, but it also covers the toilet, parking area, hotel/inn, transportation, and etcetera. Consequently, this study is necessarily carried out due to the fact that the number of people with disabilities in Indonesia is quite many, as many as 37.5 million people (Wirawan, 2015). This study employs the Mix Methods. It is a survey method strengthened by the descriptive qualitative study. The data are obtained by using questionnaire, in-depth interview, observation, and document study. The finding of this study is expected to be able to give an overview about the readiness of Batu City as a Tourism City that is disabled-friendly, thus, it can be used as a basis of fair policy making for all citizens as well as to eradicate the discrimination, particularly in the tourism activities.
Mechanical Response of Two-Dimensional Polymer Networks: Role of Topology, Rate Dependence, and Damage Accumulation
Authors: Kothari Konik , Hu Yuhang , Gupta Sahil , Elbanna Ahmed
Published: January 2018

The skeleton of many natural and artificial soft materials can be abstracted as networks of fibers/polymers interacting in a nonlinear fashion. Here, we present a numerical model for networks of nonlinear, elastic polymer chains with rate-dependent crosslinkers similar to what is found in gels. The model combines the worm-like chain (WLC) at the polymer level with the transition state theory for crosslinker bond dynamics. We study the damage evolution and the force—displacement response of these networks under uniaxial stretching for different loading rates, network topology, and crosslinking density. Our results suggest a complex nonmonotonic response as the loading rate or the crosslinking density increases. We discuss this in terms of the microscopic deformation mechanisms and suggest a novel framework for increasing toughness and ductility of polymer networks using a bio-inspired sacrificial bonds and hidden length (SBHL) mechanism. This work highlights the role of local network characteristics on macroscopic mechanical observables and opens new pathways for designing tough polymer networks.
Effect of Substrate Thickness and Preheating on the Distortion of Laser Deposited Ti–6Al–4V
Authors: Corbin David J. , Nassar Abdalla R. , Reutzel Edward W. , Beese Allison M. , Michaleris Pan
Published: January 2018

The effect of substrate surface preheating on part distortion in laser cladding is investigated through the experimental results of laser deposited Ti–6Al–4V. In situ temperature and distortion measurements were used to monitor the behavior of the substrates before, during, and after deposition. The resulting trends were analyzed, and it was determined that substrate preheating reduces the amount of distortion accumulated in thin substrates but increases the amount of distortion accumulated in thick substrates. Additionally, substrate preheating was found to cause additional distortion of thick substrates during cool-down after processing had finished. The in situ measurements suggest that the stress relaxation of Ti–6Al–4V at elevated temperatures increases the distortion observed in thick substrates, but has minimal effect on distortion in thin substrates.
Assessing Airflow Sensitivity to Healthy and Diseased Lung Conditions in a Computational Fluid Dynamics Model Validated In Vitro
Authors: Sul Bora , Oppito Zachary , Jayasekera Shehan , Vanger Brian , Zeller Amy , Morris Michael , Ruppert Kai , Altes Talissa , Rakesh Vineet , Day Steven , Robinson Risa , Reifman Jaques , Wallqvist Anders
Published: January 2018

Computational models are useful for understanding respiratory physiology. Crucial to such models are the boundary conditions specifying the flow conditions at truncated airway branches (terminal flow rates). However, most studies make assumptions about these values, which are difficult to obtain in vivo. We developed a computational fluid dynamics (CFD) model of airflows for steady expiration to investigate how terminal flows affect airflow patterns in respiratory airways. First, we measured in vitro airflow patterns in a physical airway model, using particle image velocimetry (PIV). The measured and computed airflow patterns agreed well, validating our CFD model. Next, we used the lobar flow fractions from a healthy or chronic obstructive pulmonary disease (COPD) subject as constraints to derive different terminal flow rates (i.e., three healthy and one COPD) and computed the corresponding airflow patterns in the same geometry. To assess airflow sensitivity to the boundary conditions, we used the correlation coefficient of the shape similarity (R) and the root-mean-square of the velocity magnitude difference (Drms) between two velocity contours. Airflow patterns in the central airways were similar across healthy conditions (minimum R, 0.80) despite variations in terminal flow rates but markedly different for COPD (minimum R, 0.26; maximum Drms, ten times that of healthy cases). In contrast, those in the upper airway were similar for all cases. Our findings quantify how variability in terminal and lobar flows contributes to airflow patterns in respiratory airways. They highlight the importance of using lobar flow fractions to examine physiologically relevant airflow characteristics.
Experimental Demonstration of Safety of AHWR during Stagnation Channel Break Condition in an Integral Test Loop
Authors: Kumar Mukesh , Nayak A. K. , Prasad Sumit V. , Verma P. K. , Singh R. K. , Jain Vikas , Chandraker D. K.
Published: January 2018

Detection of loss of coolant accident (LOCA) and generation of reactor trip signal for shutting down the reactor is very important for safety of a nuclear reactor. Large break LOCA (LBLOCA) is a typical design basis accident in all reactors and has attracted attention of the reactor designers. However, studies reveal that small break loss of coolant accident (SBLOCA) can be more severe as it is difficult to detect with conventional methods to generate reactor trip. SBLOCA in channel-type reactors is essential to consider as it may create stagnation channel conditions in the reactor coolant channel, which may lead to fuel failure, if the reactor is not tripped. Advanced heavy water reactor (AHWR) is a channel-type boiling water reactor, which may experience stagnation channel conditions in case of SBLOCA in feeder pipes. For initiating the trip signals and safe shut down of the reactor in such cases, a novel system comprising of acoustic-based sensors is incorporated in the reactor design. The system detects the peculiar sound of the steam leaked from the main heat transport system (MHTS) and generates reactor trip signal. The experimental demonstration of such new system is essential before its introduction in the reactor. The experimental demonstration of the stagnation channel break, its detection by acoustic-based sensors system, and reactor trip followed by generation of reactor trip signal was performed and presented in the paper. The experiment showed that the trip signal for AHWR can be generated within 5 s with acoustic sensor and 2 s by low flow signal and reactor trip can be ensured in 7 s following a LOCA.
Verification of a Total Lagrangian ANCF Solution Procedure for Fluid–Structure Interaction Problems
Authors: Grossi Emanuele , Shabana Ahmed A.
Published: January 2018

The objective of this investigation is to verify a new total Lagrangian continuum-based fluid model that can be used to solve two- and three-dimensional fluid–structure interaction problems. Large rotations and deformations experienced by the fluid can be captured effectively using the finite element (FE) absolute nodal coordinate formulation (ANCF). ANCF elements can describe arbitrarily complex fluid shapes without imposing any restriction on the amount of rotation and deformation within the finite element, ensure continuity of the time-rate of position vector gradients at the nodal points, and lead to a constant mass matrix regardless of the magnitude of the fluid displacement. Fluid inertia forces are computed, considering the change in the fluid geometry as the result of the large displacements. In order to verify the ANCF solution, the dam-break benchmark problem is solved in the two- and three-dimensional cases. The motion of the fluid free surface is recorded before and after the impact on a vertical wall placed at the end of the dam dry deck. The results are in good agreement with those obtained by other numerical methods. The results obtained in this investigation show that the number of degrees-of-freedom (DOF) required for ANCF convergence is around one order of magnitude less than what is required by other existing methods. Limitations and advantages of the verified ANCF fluid model are discussed.
Elastic–Viscoelastic Composite Structures Analysis With an Improved Burgers Model
Authors: Ren Shanhong , Zhao Guozhong , Zhang Shunqi
Published: January 2018

Composite structures integrated with viscoelastic materials are becoming more and more popular in the application of vibration suppression. This paper presents a comprehensive approach for analyzing this class of structures with an improved Burgers model, from material constitutive modeling, finite element formulation to solution method. The refined model consists of a spring component and multiple classical Burgers components in parallel, where the spring component converts the viscoelastic fluid model to a viscoelastic solid model and the multiple Burgers components increase the accuracy. Through the introduction of auxiliary coordinates, the model is applied to the finite element formulation of composites structures with viscoelastic materials. Consequently, a complicated Volterra integro-differential equation is transformed into a standard second-order differential equation and solution techniques for linear elastic structures can be directly used for elastic–viscoelastic composite structures. The improved Burgers model is a second-order mini-oscillator model, in which every mini-oscillator term has four parameters. The model parameters determination is performed by optimization algorithm. By comparison of model fitting results for a typical viscoelastic material, the refined model is better in accuracy than Golla–Hughes–McTavish (GHM) model and original Burgers model. Finally, several numerical examples are presented to further verify the effectiveness of the improved Burgers model.
Effect of the Combustor Wall on the Aerothermal Field of a Nozzle Guide Vane
Authors: Aslanidou Ioanna , Rosic Budimir
Published: January 2018

In gas turbines with can combustors, the trailing edge (TE) of the combustor transition duct wall is found upstream of every second vane. This paper presents an experimental and numerical investigation of the effect of the combustor wall TE on the aerothermal performance of the nozzle guide vane. In the measurements carried out in a high-speed experimental facility, the wake of this wall is shown to increase the aerodynamic loss of the vane. On the other hand, the wall alters secondary flow structures and has a protective effect on the heat transfer in the leading edge-endwall junction, a critical region for component life. The different clocking positions of the vane relative to the combustor wall are tested experimentally and are shown to alter the aerothermal field. The experimental methods and processing techniques adopted in this work are used to highlight the differences between the different cases studied.
Aerodynamic Optimization of a Transonic Centrifugal Compressor by Using Arbitrary Blade Surfaces
Authors: Hehn Alexander , Mosdzien Moritz , Grates Daniel , Jeschke Peter
Published: January 2018

A transonic centrifugal compressor was aerodynamically optimized by means of a numerical optimization process. The objectives were to increase the isentropic efficiency and to reduce the acoustic signature by decreasing the amplitude of pre-shock pressure waves at the inlet of the compressor. The optimization was performed at three operating points on the 100% speed line in order to maintain choke mass flow and surge margin. At the design point, the specific work input was kept equal. The baseline impeller was designed by using ruled surfaces due to requirements for flank milling. To investigate the benefits of arbitrary blade surfaces, the restrictions of ruled surfaces were abolished and fully three-dimensional (3D) blade profiles allowed. In total, therefore, 45 parameters were varied during the optimization. The combined geometric and aerodynamic analysis reveals that a forward swept leading edge (LE) and a concave suction side at the tip of the LE are effective design features for reducing the shock strength. Beyond that, the blade shape of the optimized compressor creates a favorable impeller outlet flow, which is the main reason why the performance of the vaneless diffuser improves. In total, a gain of 1.4% points in isentropic total-to-static efficiency, evaluated by computational fluid dynamics (CFD) at the exit plane of the vaneless diffuser, is achieved.
Molecular Epidemiology of Emerging
bla
OXA-23-Like
- and
bla
OXA-24-Like
-Carrying Acinetobacter baumannii in Taiwan
Authors: Kuo Shu-Chen , Huang Wei-Cheng , Huang Tzu-Wen , Wang Hui-Ying , Lai Jui-Fen , Chen Te-Li , Lauderdale Tsai-Ling
Published: January 2018

The rate of recovery of carbapenem-resistant
Acinetobacter baumannii
(CRAB) isolates has increased significantly in recent decades in Taiwan. This study investigated the molecular epidemiology of CRAB with a focus on the mechanisms of resistance and spread in isolates with
bla
OXA-23-like
or
bla
OXA-24-like
. All 555 CRAB isolates in our multicenter collection, which were recovered from 2002 to 2010, were tested for the presence of class A, B, and D carbapenemase genes. All isolates with
bla
OXA-23-like
or
bla
OXA-24-like
were subjected to pulsed-field gel electrophoresis, and 82 isolates (60 isolates with
bla
OXA-23-like
and 22 isolates with
bla
OXA-24-like
) were selected for multilocus sequence typing to determine the sequence type (ST) and clonal group (CG) and for detection of additional β-lactamase and aminoglycoside resistance genes. The flanking regions of carbapenem and aminoglycoside resistance genes were identified by PCR mapping and sequencing. The localization of
bla
OXA
was determined by S1 nuclease and I-CeuI assays. The numbers of CRAB isolates carrying
bla
OXA-23-like
or
bla
OXA-24-like
, especially those carrying
bla
OXA-23-like
, increased significantly from 2008 onward. The
bla
OXA-23-like
gene was carried by antibiotic resistance genomic island 1 (AbGRI1)-type structures located on plasmids and/or the chromosome in isolates of different STs (CG92 and novel CG786), whereas
bla
OXA-24-like
was carried on plasmids in CRAB isolates of limited STs (CG92). No class A or B carbapenemase genes were identified. Multiple aminoglycoside resistance genes coexisted in CRAB. Tn
6180
-borne
armA
was found in 74 (90.2%) CRAB isolates, and 58 (70.7%) isolates had Tn
6179
upstream, constituting AbGRI3.
bla
TEM
was present in 38 (46.3%) of the CRAB isolates tested, with 35 (92.1%) isolates containing
bla
TEM
in AbGRI2-type structures, and 61% of
ampC
genes had IS
Aba1
upstream. We conclude that the dissemination and spread of a few dominant lineages of CRAB containing various resistance island structures occurred in Taiwan.
Population Pharmacokinetics of Polymyxin B in Acutely Ill Adult Patients
Authors: Miglis Cristina , Rhodes Nathaniel J. , Avedissian Sean N. , Kubin Christine J. , Yin Michael T. , Nelson Brian C. , Pai Manjunath P. , Scheetz Marc H.
Published: January 2018

Polymyxin B (PB) has reemerged as a common treatment against multidrug-resistant Gram-negative pathogens. However, nephrotoxicity remains a significant dose-limiting side effect, and contemporary pharmacokinetic (PK) data are limited. This study sought to evaluate PB exposure differences in various loading and nonloading strategies according to total body weight (TBW) and adjusted body weight (ABW). Patients treated with PB had plasma samples obtained for clinical care and analyzed using liquid chromatography-tandem mass spectrometry. Compartmental PK models with linear and allometric scaling of TBW were explored. Semiparametric Monte Carlo simulation evaluated the total (i.e., protein bound plus unbound) area under the plasma concentration-time curve (AUC
total
) during the first 24 h of therapy and at 96 h posttherapy for each regimen at the 10th, 50th, and 90th percentiles of TBW and ABW in the derivation cohort. Literature-based values of the 24-h total AUC/MIC ratio (AUC/MIC
total
) of ≥50 defined efficacy, and literature-based values of the 72- to 96-h AUC
total
of ≥100 μg · h/ml defined toxicity. Fifty-two patients contributed 156 PB plasma samples. A two-compartment model with allometric scaling of TBW produced a comparable fit (Akaike information criterion [AIC] = 376.7) to that achieved with linear scaling (AIC = 378). The regimen of a loading dose of 2.5 mg/kg of body weight plus a fixed dose of 100 mg every 12 h had the highest probability of achieving a 24-h AUC/MIC
total
of ≥50 with the lowest probability of toxicity in all groups at 24 h, aside from those with the lowest 10th percentile of body weight. This is the first study to suggest that a weight-based loading and fixed maintenance (i.e., weight-independent) dosing strategy for polymyxin B may maximize efficacy while balancing toxicity concerns for most patients.
Deletion of
ADA2
Increases Antifungal Drug Susceptibility and Virulence in Candida glabrata
Authors: Yu Shang-Jie , Chang Ya-Lin , Chen Ying-Lien
Published: January 2018

Candida glabrata
, the second most frequent cause of candidiasis after
Candida albicans
, is an emerging human fungal pathogen that is intrinsically drug tolerant. Currently, studies of
C. glabrata
genes involved in drug tolerance are limited. Ada2, a component serving as a transcription adaptor of the Spt-Ada-Gcn5 acetyltransferase (SAGA) complex, is required for antifungal drug tolerance and virulence in
C. albicans
. However, its roles in
C. glabrata
remain elusive. In this study, we found that
ada2
mutants demonstrated severe growth defects at 40°C but only mild defects at 37°C or 25°C. In addition,
C. glabrata ada2
mutants exhibited pleiotropic phenotypes, including susceptibility to three classes of antifungal drugs (i.e., azoles, echinocandins, and polyenes) and cell wall-perturbing agents but resistance to the endoplasmic reticulum stressor tunicamycin. According to RNA sequence analysis, the expression of 43 genes was downregulated and the expression of 442 genes was upregulated in the
ada2
mutant compared to their expression in the wild type.
C. glabrata ADA2
, along with its downstream target
ERG6
, controls antifungal drug tolerance and cell wall integrity. Surprisingly,
ada2
mutants were hypervirulent in a murine model of systemic infection, possibly due to the upregulation of multiple adhesin-like genes, increased agar invasion, and overstimulation of murine tumor necrosis factor alpha production.
Metals and Methanotrophy
Authors: Semrau Jeremy D. , DiSpirito Alan A. , Gu Wenyu , Yoon Sukhwan
Published: January 2018

Aerobic methanotrophs have long been known to play a critical role in the global carbon cycle, being capable of converting methane to biomass and carbon dioxide. Interestingly, these microbes exhibit great sensitivity to copper and rare-earth elements, with the expression of key genes involved in the central pathway of methane oxidation controlled by the availability of these metals. That is, these microbes have a “copper switch” that controls the expression of alternative methane monooxygenases and a “rare-earth element switch” that controls the expression of alternative methanol dehydrogenases. Further, it has been recently shown that some methanotrophs can detoxify inorganic mercury and demethylate methylmercury; this finding is remarkable, as the canonical organomercurial lyase does not exist in these methanotrophs, indicating that a novel mechanism is involved in methylmercury demethylation. Here, we review recent findings on methanotrophic interactions with metals, with a particular focus on these metal switches and the mechanisms used by methanotrophs to bind and sequester metals.
Mycoplasma bovis-Induced Inhibition of Bovine Peripheral Blood Mononuclear Cell Proliferation Is Ameliorated after Blocking the Immune-Inhibitory Programmed Death 1 Receptor
Authors: Suleman Muhammad , Cyprian Farhan S. , Jimbo Steve , Maina Teresia , Prysliak Tracy , Windeyer Claire , Perez-Casal Jose
Published: January 2018

Mycoplasma bovis
-induced immune suppression is a major obstacle faced by the host for controlling infections.
M. bovis
impairment of antigen-specific T-cell responses is achieved through inhibiting the proliferation of peripheral blood mononuclear cells (PBMCs). This impairment may contribute to the persistence of
M. bovis
infection in various sites, including lungs, and its systemic spread to various organs such as joints, with the underlying mechanisms remaining elusive. Here, we elucidated the role of the immune-inhibitory receptor programmed death 1 (PD-1) and its ligand (PD-L1) in
M. bovis
infection. Flow cytometry (FCM) analyses revealed an upregulation of PD-L1 expression on tracheal and lung epithelial cell lines after
M. bovis
infection. In addition, we found increased PD-L1 expression on purified lung lavage macrophages following
M. bovis
infection by FCM and determined its localization by immunofluorescence analysis comparing infected and control lung tissue sections. Moreover,
M. bovis
infection increased the expression of the PD-1 receptor on total PBMCs and in gated CD4
+
and CD8
+
T-cell subpopulations. We demonstrated that
M. bovis
infection induced a significant decrease in CD4
+
PD-1
INT
and CD8
+
PD-1
INT
subsets with intermediate PD-1 expression, which functioned as progenitor pools giving rise to CD4
+
PD-1
HIGH
and CD8
+
PD-1
HIGH
subsets with high PD-1 expression levels. We blocked PD-1 receptors on PBMCs using anti-PD-1 antibody at the beginning of infection, leading to a significant restoration of the proliferation of PBMCs. Taken together, our data indicate a significant involvement of the PD-1/PD-L1 inhibitory pathway during
M. bovis
infection and its associated immune exhaustion, culminating in impaired host immune responses.
Evaluation of Simplexa Group A Strep Direct Kit Compared to Hologic Group A Streptococcal Direct Assay for Detection of Group A Streptococcus in Throat Swabs
Authors: Church Deirdre L. , Lloyd Tracie , Larios Oscar , Gregson Daniel B.
Published: January 2018

Diagnosis of bacterial pharyngitis is confirmed by detection of group A
Streptococcus
(GAS) in patient throat samples. Testing of throat samples has historically relied on culture, but new molecular methods allow much faster test turnaround time (i.e., same day versus 48 to 72 h for culture). Our laboratory uses the Hologic GAS Direct (GASD) assay for screening more than 125,000 throat samples per year. Simplexa GAS Direct is a new real-time quantitative PCR (qPCR) assay that does not require initial DNA extraction. Performance of Simplexa qPCR was compared to GASD. A total of 289 throat swabs were collected from patients attending ambulatory clinics in Calgary, Alberta, Canada. A total of 60 (20.8%) of the samples were initially GAS positive by either method: 54 by both methods, 4 by Simplex qPCR alone, and 2 by GASD alone. An in-house PCR using a unique GAS primer set was used to resolve the 6 discrepant results. Overall, GASD compared to Simplexa qPCR had a sensitivity, specificity, positive predictive value, and negative predictive value of 93.1% versus 100%, 100% versus 100%, 100% versus 100%, and 98.31% versus 100%, respectively. Implementation of Simplexa qPCR in our laboratory setting would cost more but allow the high sample volume to be reported in half the time and save 0.62 medical laboratory technician (MLT) full-time equivalent (FTE). In comparison to culture, the implementation of Simplexa qPCR would save 2.79 medical laboratory assistant (MLA) FTE plus 0.94 MLT FTE. Simplexa qPCR has improved performance and diagnostic efficiency in a high-volume laboratory compared to GASD for GAS detection in throat swabs.
Direct-from-Blood-Culture Disk Diffusion To Determine Antimicrobial Susceptibility of Gram-Negative Bacteria: Preliminary Report from the Clinical and Laboratory Standards Institute Methods Development and Standardization Working Group
Authors: Chandrasekaran Sukantha , Abbott April , Campeau Shelley , Zimmer Barbara L. , Weinstein Melvin , Thrupp Lauri , Hejna John , Walker Lindsey , Ammann Tracy , Kirn Thomas , Patel Robin , Humphries Romney M.
Published: January 2018

The performance of a disk diffusion test using broth from positive blood cultures as inoculum (direct disk diffusion [dDD]) was evaluated for a collection of 20 challenge isolates of
Enterobacteriaceae
,
Acinetobacter baumannii
, and
Pseudomonas aeruginosa
. Isolates seeded into human blood were inoculated into Bactec Plus Aerobic/F, VersaTREK Redox 1, and BacT/Alert FA Plus bottles and incubated in the respective automated blood culture systems. Disk diffusion results were compared to reference disk diffusion results. Categorical agreement (CA) values for dDD, after removal of random errors due to natural MIC variation, were 87.8%, 88.4%, and 92.2% for the BacT/Alert, Bactec, and VersaTREK systems, respectively. No very major errors (VME) were observed, and major error (ME) rates were 3.0%, 2.3%, and 1.7%, respectively. Incubation of the dDD test samples for 6 h compared to incubation for 16 to 18 h resulted in 19.9% of tests having too light of growth to allow reading of zones of inhibition. Among the evaluable dDD tests, CA values were 58.9%, 76.6%, and 73.2% for the isolates seeded into the BacT/Alert, Bactec, and VersaTREK systems, respectively. VME rates for isolates seeded into these systems were 2.2%, 1.8%, and 3.0%, respectively, and ME rates were 25.4%, 6.1%, and 2.8%, respectively, at the 6-h reading. The best performance of dDD was found for blood cultures with bacterial concentrations in the range of 7.6 × 10
7
to 5.0 × 10
8
CFU/ml; CA values ranged from 94.7 to 96.2% for these concentrations after 18 h of incubation and from 76.9 to 84.1% after 6 h of incubation. These preliminary data demonstrate the potential accuracy of dDD testing by the clinical laboratory.