bluuebunny/crossref_metadata_2025 huggingface dataset:
(E)-2-(3-Oxo-3-phenylprop-1-enyl)thiophene-3-carbaldehyde
Authors: Elumalai K. , Raja R. , Karunakaran Jayachandran , Mohanakrishnan Arasambattu K. , Murugesan K. Sakthi
Published: January 2018

The title compound, C14H10O2S, crystallizes with two independent molecules (A and B) in the asymmetric unit. They have very similar conformations with the thiophene ring having an envelope conformation in both molecules. In molecule A, the benzene and thiophene rings makes a dihedral angle of 11.01 (9)°. The corresponding angle in molecule B is 9.58 (9)°. In the crystal, molecules are linked via pairs of C—H...O hydrogen bonds, forming dimers with an R
2
2(18)set-graph motif. The dimers are linked via C—H...O hydrogen bonds, forming slabs lying parallel to (100).
(E)-1-(4-Bromophenyl)-3-[3-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one
Authors: El-Hiti Gamal A. , Abdel-Wahab Bakr F. , Alotaibi Mohammad Hayal , Hegazy Amany S. , Kariuki Benson M.
Published: January 2018

In the title compound, C27H20BrN5O, the dihedral angle between the heterocyclic rings is 10.2 (2)°. The phenyl ring bound to the triazole ring is disordered over two orientations in a 0.808 (4):0.192 (4) ratio. In the crystal, C—H...O interactions form chains along [010]. π–π interactions are observed between the phenyl–pyrazolyl unit and the phenylene group of a neighbouring molecule.
The 2:1 charge-transfer complex of 4,6-dimethyldibenzothiophene and 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane
Authors: Fujii Takuya , Yamakado Hideo
Published: January 2018

The title compound, 2C14H12S·C12N4F4, was obtained by using 4,6-dimethyldibenzothiophene (DMDBT) as an electron donor and 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (F4TCNQ) as an electron acceptor. The asymmetric unit consists of one DMDBT molecule and one half of an F4TCNQ molecule, which lies on an inversion centre. In the crystal, the DMDBT and F4TCNQ molecules form a 2:1 unit via a charge-transfer interaction, with a centroid–centroid distance of 3.3681 (15) Å between the five-membered ring of DMDBT and the six-membered ring of F4TCNQ. An F...F contact [2.911 (1) Å] is also observed.
Crystal structure of Al45Cr7C0.32
Authors: Liu Cong , Fan Changzeng
Published: January 2018

During a high-pressure sintering (HPS) process of a stoichiometric Al7Cr mixture, the ternary phase Al45Cr7C0.32 (pentatetracontaaluminium heptachromium carbide) was obtained serendipitously. The C atom (occupancy 0.32) is irregularly surrounded by six Al atoms.
A hybrid global optimization method based on multiple metamodels
Authors: Cai Xiwen , Qiu Haobo , Gao Liang , Li Xiaoke , Shao Xinyu
Published: January 2018

Purpose

This paper aims to propose hybrid global optimization based on multiple metamodels for improving the efficiency of global optimization.

Design/methodology/approach

The method has fully utilized the information provided by different metamodels in the optimization process. It not only imparts the expected improvement criterion of kriging into other metamodels but also intelligently selects appropriate metamodeling techniques to guide the search direction, thus making the search process very efficient. Besides, the corresponding local search strategies are also put forward to further improve the optimizing efficiency.

Findings

To validate the method, it is tested by several numerical benchmark problems and applied in two engineering design optimization problems. Moreover, an overall comparison between the proposed method and several other typical global optimization methods has been made. Results show that the global optimization efficiency of the proposed method is higher than that of the other methods for most situations.

Originality/value

The proposed method sufficiently utilizes multiple metamodels in the optimizing process. Thus, good optimizing results are obtained, showing great applicability in engineering design optimization problems which involve costly simulations.
RANS-based design optimization of dual-rotor wind turbines
Authors: Thelen Andrew , Leifsson Leifur , Sharma Anupam , Koziel Slawomir
Published: January 2018

Purpose

An improvement in the energy efficiency of wind turbines can be achieved using dual rotors. Because of complex flow physics, the design of dual-rotor wind turbines (DRWTs) requires repetitive evaluations of computationally expensive partial differential equation (PDE) simulation models. Approaches for solving design optimization of DRWTs constrained by PDE simulations are investigated. The purpose of this study is to determine design optimization algorithms which can find optimal designs at a low computational cost.

Design/methodology/approach

Several optimization approaches and algorithms are compared and contrasted for the design of DRWTs. More specifically, parametric sweeps, direct optimization using pattern search, surrogate-based optimization (SBO) using approximation-based models and SBO using kriging interpolation models with infill criteria are investigated for the DRWT design problem.

Findings

The approaches are applied to two example design cases where the DRWT fluid flow is simulated using the Reynolds-averaged Navier−Stokes (RANS) equations with a two-equation turbulence model on an axisymmetric computational grid. The main rotor geometry is kept fixed and the secondary rotor characteristics, using up to three variables, are optimized. The results show that the automated numerical optimization techniques were able to accurately find the optimal designs at a low cost. In particular, SBO algorithm with infill criteria configured for design space exploitation required the least computational cost. The widely adopted parametric sweep approach required more model evaluations than the optimization algorithms, as well as not being able to accurately find the optimal designs.

Originality/value

For low-dimensional PDE-constrained design of DRWTs, automated optimization algorithms are essential to find accurately and efficiently the optimal designs. More specifically, surrogate-based approaches seem to offer a computationally efficient way of solving such problems.
A multi-block finite difference method for seismic wave equation in auxiliary coordinate system with irregular fluid–solid interface
Authors: Huang Jianping , Liao Wenyuan , Li Zhenchun
Published: January 2018

Purpose

The purpose of this paper is to develop a new finite difference method for solving the seismic wave propagation in fluid-solid media, which can be described by the acoustic and viscoelastic wave equations for the fluid and solid parts, respectively.

Design/methodology/approach

In this paper, the authors introduced a coordinate transformation method for seismic wave simulation method. In the new method, the irregular fluid–solid interface is transformed into a horizontal interface. Then, a multi-block coordinate transformation method is proposed to mesh every layer to curved grids and transforms every interface to horizontal interface. Meanwhile, a variable grid size is used in different regions according to the shape and the velocity within each region. Finally, a Lebedev-standard staggered coupled grid scheme for curved grids is applied in the multi-block coordinate transformation method to reduce the computational cost.

Findings

The instability in the auxiliary coordinate system caused by the standard staggered grid scheme is resolved using a curved grid viscoelastic wave field separation strategy. Several numerical examples are solved using this new method. It has been shown that the new method is stable, efficient and highly accurate in solving the seismic wave equation defined on domain with irregular fluid–solid interface.

Originality/value

First, the irregular fluid–solid interface is transformed into a horizontal interface by using the coordinate transformation method. The conversion between pressures and stresses is easy to implement and adaptive to different irregular fluid–solid interface models, because the normal stress and shear stress vanish when the normal angle is 90° in the interface. Moreover, in the new method, the strong false artificial boundary reflection and instability caused by ladder-shaped grid discretion are resolved as well.
Evaluating quality of the didactics at university: the opportunities offered by latent class modeling
Authors: Bassi Francesca , Clerici Renata , Aquario Debora
Published: January 2018

Purpose

Students’ evaluation of teaching quality plays a major role in higher education. Satisfaction is not directly observable, nevertheless it can be measured through multi-item measurement scales. These instruments are extremely useful and their importance requires accurate development and validation procedures. The purpose of this paper is to show how latent class (LC) analysis can improve the procedures for developing and validating a multi-item measurement scale for measuring students’ evaluation of teaching and, at the same time, provide a deeper insight in the phenomenon under investigation.

Design/methodology/approach

The traditional literature highlights specific protocols along with the statistical instruments to be used for achieving this goal. However, these tools are suited for metric variables but they are adopted even when the nature of the observed variables is different, as it often occurs, since in many cases the items are ordinal. LC analysis takes explicitly into account the ordinal nature of the variables and also the fact that the object of interest is unobservable.

Findings

The data refer to the questionnaire to evaluate didactics to the students of the University of Padua. Within LC analysis allows an insight of scale properties, such as dimensionality, validity and reliability. Moreover, the results provide a deeper view in the way students use the scale to report satisfaction suggesting to revise the instrument according to the suggestion by the National Agency for University Evaluation.

Originality/value

The paper gives an original contribution on two sides. On the side of methods, it introduces a more accurate methodology for evaluating scales to measure the students’ satisfaction. On the side of applications, it provides important suggestions to the university management to improve the process of quality of the didactics evaluation.
Speech and language therapists’ perspectives of therapeutic alliance construction and maintenance in aphasia rehabilitation post‐stroke
Authors: Lawton Michelle , Sage Karen , Haddock Gillian , Conroy Paul , Serrant Laura
Published: January 2018

Background

Therapeutic alliance refers to the interactional and relational processes operating during therapeutic interventions. It has been shown to be a strong determinant of treatment efficacy in psychotherapy, and evidence is emerging from a range of healthcare and medical disciplines to suggest that the construct of therapeutic alliance may in fact be a variable component of treatment outcome, engagement and satisfaction. Although this construct appears to be highly relevant to aphasia rehabilitation, no research to date has attempted to explore this phenomenon and thus consider its potential utility as a mechanism for change.

Aims

To explore speech and language therapists’ perceptions and experiences of developing and maintaining therapeutic alliances in aphasia rehabilitation post‐stroke.

Methods & Procedures

Twenty‐two, in‐depth, semi‐structured interviews were conducted with speech and language therapists working with people with aphasia post‐stroke. Qualitative data were analysed using inductive thematic analysis.

Outcomes & Results

Analysis resulted in the emergence of three overarching themes: laying the groundwork; augmenting cohesion; and contextual shapers. Recognizing personhood, developing shared expectations of therapy and establishing therapeutic ownership were central to laying the groundwork for therapeutic delivery. Augmenting cohesion was perceived to be dependent on the therapists’ responsiveness and ability to resolve both conflict and resistance, as part of an ongoing active process. These processes were further moulded by contextual shapers such as the patient's family, relational continuity and organizational drivers.

Conclusions & Implications

The findings suggest that therapists used multiple, complex, relational strategies to establish and manage alliances with people with aphasia, which were reliant on a fluid interplay of verbal and non‐verbal skills. The data highlight the need for further training to support therapists to forge purposive alliances. Training should develop: therapeutic reflexivity; inclusivity in goal setting, relational strategies; and motivational enhancement techniques. The conceptualization of therapeutic alliance, however, is only provisional. Further research is essential to elucidate the experiences and perceptions of alliance development for people with aphasia undergoing rehabilitation.
CEO Duality, Agency Costs, and Internal Capital Allocation Efficiency
Authors: Aktas Nihat , Andreou Panayiotis C. , Karasamani Isabella , Philip Dennis
Published: January 2018

This study examines the impact of CEO duality on firms’ internal capital allocation efficiency. We observe that when the CEO is also chair of the board, diversified firms make inefficient investments, as they allocate more capital to business segments with relatively low growth opportunities over segments with high growth opportunities. The adverse impact of CEO duality on investment efficiency prevails only among firms that face high agency problems, as captured by high free cash flows, staggered board structure and low board independence. Depending on the severity of the agency problem, CEO duality is associated with a decrease in industry‐adjusted investment in high‐growth segments of 1% to 2.1% over the following year, relative to that in low‐growth segments. However, CEOs’ equity‐based compensation curbs the negative effect of CEO duality on internal capital allocation efficiency. Overall, the findings of this study offer strong support for the agency theory and postulate the internal capital allocation policy as an important channel through which CEO duality lowers firm value in diversified firms.
Analysis of the Effect of Cyclophosphamide and Methotrexate on Chrysomya megacephala (Diptera: Calliphoridae),
Authors: Trivia Ana Letícia , de Carvalho Pinto Carlos José
Published: January 2018

Forensic entomotoxicology investigates the effects of chemical substances in the development of scavenger insects and the reflection on estimating the minimum postmortem interval (PMI). To evaluate the impact of the chemotherapeutic drugs cyclophosphamide (CF) and methotrexate (MTX) on the postembryonic development of Chrysomya megacephala, controlled experiments were performed by rearing the larvae on spiked minced beef with different concentrations of these drugs. The results indicated that CF significantly decreased their developmental rate up to 28 h but had no significant effect on larval and adult sizes, survival rate, and sex ratio, whereas MTX decreased larval and adult sizes, survival rate, and there was a deviation in the expected sex ratio toward females in MTX‐exposed larvae but had no significant impact on developmental rate. These negative interference factors should be considered in cases of suspected death of people that have undergone chemotherapy.
Further Evidence That Sleep Deprivation Effects and the Vigilance Decrement Are Functionally Equivalent: Comment on Altmann (2018)
Authors: Gunzelmann Glenn , Veksler Bella
Published: January 2018

Veksler and Gunzelmann (2018) argue that the vigilance decrement and the deleterious effects of sleep loss reflect functionally equivalent degradations in cognitive processing and performance. Our account is implemented in a cognitive architecture, where these factors produce breakdowns in goal‐directed cognitive processing that we refer to as microlapses. Altmann (2018) raises a number of challenges to microlapses as a unified account of these deficits. Under scrutiny, however, the challenges do little to discredit the theory or conclusions in the original paper. In our response, we address the most serious challenges. In so doing, we provide additional support for the theory and mechanisms, and we highlight opportunities for extending their explanatory breadth.
Urban geology: modelling Coal Measures strata in the nineteenth and twenty‐first centuries
Authors: Donovan Stephen K.
Published: January 2018

Displays of artificial geological artefacts may be accurate, but not always. Examination of restorations of Coal Measure (Upper Carboniferous, Pennsylvanian) strata in two public displays shows how standards vary. In Crystal Palace Park, London (opened 1854), Coal Measures are accurately displayed and explained in detail. These beds are faulted, and associated features such as nodular mudrocks are displayed, although the density of nodules may be inaccurate. In contrast, in the Dutch National Railway Museum, Het Spoorwegmuseum, Utrecht, the Netherlands (reopened 2005), the portrayal of Pennsylvanian strata (sandstones?) of north‐east England gives them a uniform colour and poor bedding. Although there is a reconstruction of part of a coal mine, coal(?) forms lenses, not beds, and is the same brown hue as the sandstone. Museums and theme parks need to pursue the expertise of knowledgeable local geologists if they are to accurately model geological phenomena.
The Asosa region of western Ethiopia: a golden exploration opportunity
Authors: Bullock Liam A. , Morgan Owen
Published: January 2018

Gold mining has a legendary history in Ethiopia, with Ethiopian mines providing gold to the ancient Egyptian empire and possibly even King Solomon's Mines and the Queen of Sheba. Today, gold occurs in the Pan‐African age schist belt and Tertiary basaltic lavas of the Asosa region of Benishangul‐Gumuz, western Ethiopia. There is widespread artisanal gold production in the Asosa region, with moderate activity by small numbers of local workers producing relatively large amounts of gold. There is a strong relationship between predominantly shear zone‐hosted gold deposits and the Kuluck shear zone, suggesting a structural control on gold accumulation. Gold is also commonly associated with secondary sulphide mineralization and magnetite alteration in Asosa rocks. The source of the gold is thought to be the sub‐volcanic intrusions generated during the subduction of the oceanic crust at the trench island‐arc system, akin to what we see today in epithermal and porphyry type gold systems. Historical workings and anomalous gold concentrations in rock, soil and stream sediments point to a potentially significant untapped gold resource in the Asosa region of western Ethiopia.
Meeting (or not) at the street level? A literature review on street‐level research in public management, social policy and social work
Authors: Nothdurfter Urban , Hermans Koen
Published: January 2018

This literature review analyses the adoption and development of a street‐level perspective in public management, social policy and social work. The last years have seen a prominent revival of a perspective based on Michael Lipsky's street‐level bureaucracy approach in the debates conducted within all three disciplinary fields. Based on 71 key publications in public management, social policy and social work, the review analyses the adoption of the street‐level bureaucracy approach during the period 2005–2015, pointing out the main themes of the debate within, as well as overlaps and differences between, the three disciplines. The findings show the potential of better integrating the different perspectives and taking stock of the articulated debate. Lastly, the review discerns a common viewpoint for further street‐level research, emphasising its importance for the critical analysis and understanding of street‐level work as a vital dimension of responsive and accountable institutions and as a decisive moment to shape positive policy outcomes on the ground.

Key Practitioner Message: • The use of discretion by frontline practitioners and their role as policy actors on the ground has become an important focus of research; • This literature review shows that the debate has gone far beyond discussing discretion as an all‐or‐nothing issue, pointing out both positive and negative aspects of discretion and developing comprehensive frameworks to explain the use of discretion at the street‐level; • However, street‐level research has traditionally rather neglected the notion of professionalism. The social work literature brings in the perspective of professionalism; more research efforts are needed to better explore and explain how professionalism matters in relation to challenges and dilemmas of different policy and practice fields.
Promises and pitfalls in the development of biomarkers that can promote early intervention in children at risk
Authors: Jaffee Sara
Published: January 2018

The cost to individuals and to society of psychopathology that emerges in childhood is substantial. Children whose problems are undiagnosed or inadequately treated struggle in school, experience rejection by peers, and become a source of stress for caregivers and teachers. As adults, their mental health problems tend to recur and their cognitive difficulties persist. Clinicians hold a well‐founded belief that early identification of children who are at risk for psychopathology is the key to prevention.
Accuracy of a new elastomeric impression material for complete‐arch dental implant impressions
Authors: Baig Mirza R. , Buzayan Muaiyed M. , Yunus Norsiah
Published: January 2018

Aim

The aim of the present study was to assess the accuracy of multi‐unit dental implant casts obtained from two elastomeric impression materials, vinyl polyether silicone (VPES) and polyether (PE), and to test the effect of splinting of impression copings on the accuracy of implant casts.

Methods

Forty direct impressions of a mandibular reference model fitted with six dental implants and multibase abutments were made using VPES and PE, and implant casts were poured (N = 20). The VPES and PE groups were split into four subgroups of five each, based on splinting type: (a) no splinting; (b) bite registration polyether; (c) bite registration addition silicone; and (d) autopolymerizing acrylic resin. The accuracy of implant‐abutment replica positions was calculated on the experimental casts, in terms of interimplant distances in the x, y, and z‐axes, using a coordinate measuring machine; values were compared with those measured on the reference model. Data were analyzed using non‐parametrical Kruskal‐Wallis and Mann‐Whitney tests at α = .05.

Results

The differences between the two impression materials, VPES and PE, regardless of splinting type, were not statistically significant (P>.05). Non‐splinting and splinting groups were also not significantly different for both PE and VPES (P>.05).

Conclusions

The accuracy of VPES impression material seemed comparable with PE for multi‐implant abutment‐level impressions. Splinting had no effect on the accuracy of implant impressions.
Association between breast milk intake at 9–10 months of age and growth and development among Malawian young children
Authors: Kumwenda Chiza , Hemsworth Jaimie , Phuka John , Ashorn Ulla , Arimond Mary , Maleta Kenneth , Prado Elizabeth L. , Haskell Marjorie J. , Dewey Kathryn G. , Ashorn Per
Published: January 2018

World Health Organization recommends exclusive breastfeeding for infants for the first 6 months of life, followed by introduction of nutritious complementary foods alongside breastfeeding. Breast milk remains a significant source of nourishment in the second half of infancy and beyond; however, it is not clear whether more breast milk is always better. The present study was designed to determine the association between amount of breast milk intake at 9–10 months of age and infant growth and development by 12–18 months of age. The study was nested in a randomized controlled trial conducted in Malawi. Regression analysis was used to determine associations between breast milk intake and growth and development. Mean (SD) breast milk intake at 9–10 months of age was 752 (244) g/day. Mean (SD) length‐for‐age z‐score at 12 months and change in length‐for‐age z‐score between 12 and 18 months were −1.69 (1.0) and −0.17 (0.6), respectively. At 18 months, mean (SD) expressive vocabulary score was 32 (24) words and median (interquartile range) skills successfully performed for fine, gross, and overall motor skills were 21 (19–22), 18 (16–19), and 38 (26–40), respectively. Breast milk intake (g/day) was not associated with either growth or development. Proportion of total energy intake from breast milk was negatively associated with fine motor (β = −0.18,p = .015) but not other developmental scores in models adjusted for potential confounders. Among Malawian infants, neither breast milk intake nor percent of total energy intake from breast milk at 9–10 months was positively associated with subsequent growth between 12 and 18 months, or development at 18 months.
Evaluation of the stability and stratification of propofol and ketamine mixtures for pediatric anesthesia
Authors: Izgi Murat , Basaran Betul , Muderrisoglu Ahmet , Ankay Yilbas Aysun , Uluer Mehmet S. , Celebioglu Bilge
Published: January 2018

Background

The combination of propofol and ketamine is commonly used for total intravenous anesthesia. These drugs can be delivered in different syringes or in the same syringe. We hypothesized that the drugs might separate and different concentrations of each drug could be found in different parts of the syringe during the procedure period when they were mixed in 1 syringe.

Methods

Twelve 60‐mL polypropylene syringes were prepared by mixing propofol and ketamine as 4 groups on the basis of propofol/ketamine mixture ratios (5:1 and 6.7:1) and propofol solution concentrations. Syringes were placed upright in the vertical position into a rack and kept at room temperature (21.5‐22.5°C), in daylight conditions and were not moved for 360 minutes. Samples of the mixture were taken from both the top and the bottom of the syringe. The first 1 mL of the samples was discarded, the following second 1 mL of the samples was filtered using 0.2‐μm polytetrafluoroethylene filters and measured twice (n = 6). Samples were taken at the following time intervals: T0, T10, T30, T60, T90, T120, T180, T240, T300, and T360 min. Syringes were checked visually for any color change and separation lines between the drugs.

Results

There were no significant differences between the propofol and ketamine concentrations of the top and bottom samples in all 4 groups. In addition, there were no statistically significant changes of propofol and ketamine concentrations of samples over 360 minutes in any of the 4 groups. No visual changes were observed during 6 hours’ observation.

Conclusion

The results of our measurements demonstrated that mixtures of propofol (1% and 2%) and ketamine at 5:1 and 6.7:1 ratios could be used in terms of mixture homogeneity and stability in a polypropylene syringe during a 6‐hour period at room temperature.
Sprint performance and propulsion asymmetries on an ergometer in trained high‐ and low‐point wheelchair rugby players
Authors: Goosey‐Tolfrey V. L. , Vegter R. J. K. , Mason B. S. , Paulson T. A. W. , Lenton J. P. , van der Scheer J. W. , van der Woude L. H. V.
Published: January 2018

The purpose of this study was to examine the propulsion asymmetries of wheelchair athletes while sprinting on an instrumented, dual‐roller ergometer system. Eighteen experienced wheelchair rugby players (8 low point (LP) (class ≤1.5) and 10 high point (HP) (class ≥2.0)) performed a 15‐second sprint in their sports wheelchair on the instrumented ergometer. Asymmetry was defined as the difference in distance and power output (PO) between left and right sides when the best side reached 28 m. Propulsion techniques were quantified based on torque and velocity data. HP players covered an average 3 m further than the LP players (P = .002) and achieved faster sprint times than LP players (6.95 ± 0.89 vs 8.03 ± 0.68 seconds, P = .005) and at the time the best player finished (5.96 seconds). Higher peak POs (667 ± 108 vs 357 ± 78 W, P = .0001) and greater peak speeds that were also evident were for HP players (4.80 ± 0.71 vs 4.09 ± 0.45 m/s, P = .011). Greater asymmetries were found in HP players for distance (1.86 ± 1.43 vs 0.70 ± 0.65 m, P = .016), absolute peak PO (P = .049), and speed (0.35 ± 0.25 vs 0.11 ± 0.10 m/s, P = .009). Although HP players had faster sprint times over 28 m (achieved by a higher PO), high standard deviations show the heterogeneity within the two groups (eg, some LP players were better than HP players). Quantification of asymmetries is important not only for classifiers but also for sports practitioners wishing to improve performance as they could be addressed through training and/or wheelchair configuration.
Reduced left ventricular filling following blood volume extraction does not result in compensatory augmentation of cardiac mechanics
Authors: Lord Rachel , MacLeod David , George Keith , Oxborough David , Shave Rob , Stembridge Mike
Published: January 2018

New Findings

What is the central question of this study?

A reduction in left ventricular (LV) filling, and concomitant increase in heart rate, augments LV mechanics to maintain stroke volume (SV); however, the impact of reduced LV filling in isolation on SV and LV mechanics is currently unknown.

What is the main finding and its importance?

An isolated decrease in LV filling did not provoke a compensatory increase in mechanics to maintain SV; in contrast, LV mechanics and SV were reduced. These data indicate that when LV filling is reduced without changes in heart rate, LV mechanics do not compensate to maintain SV.

An acute non‐invasive reduction in preload has been shown to augment cardiac mechanics to maintain stroke volume and cardiac output. Such interventions induce concomitant changes in heart rate, whereas blood volume extraction reduces preload without changes in heart rate. Therefore, the purpose of this study was to determine whether a preload reduction in isolation resulted in augmented stroke volume achieved via enhanced cardiac mechanics. Nine healthy volunteers (four female, age 29 ± 11 years) underwent echocardiography for the assessment of left ventricular (LV) volumes and mechanics in a supine position at baseline and end extraction after the controlled removal of 25% of total blood volume (1062 ± 342 ml). Arterial blood pressure was monitored continuously by a pressure transducer attached to an indwelling radial artery catheter. Heart rate and total peripheral resistance were unchanged from baseline to end extraction, but systolic blood pressure was reduced (from 148 to 127 mmHg). From baseline to end extraction there were significant reductions in left ventricular end‐diastolic volume (from 89 to 71 ml) and stroke volume (from 56 to 37 ml); however, there was no change in LV twist, basal or apical rotation. In contrast, LV longitudinal strain (from −20 to −17%) and basal circumferential strain (from −22 to −19%) were significantly reduced from baseline to end extraction. In conclusion, a reduction in preload during blood volume extraction does not result in compensatory changes in stroke volume or cardiac mechanics. Our data suggest that LV strain is dependent on LV filling and consequent geometry, whereas LV twist could be mediated by heart rate.
Dynamic Tensile Response of Additively Manufactured Ti6Al4V With Embedded Spherical Pores
Authors: Fadida Refael , Shirizly Amnon , Rittel Daniel
Published: January 2018

The dynamic tensile response of additively manufactured (AM) dense and porous Ti6Al4V specimens was investigated under quasi-static and dynamic tension. The porous specimens contained single embedded spherical pores of different diameters. Such artificial spherical pores can mimic the behavior of realistic flaws in the material. It was found that beyond a certain pore diameter (Ø600 μm), the failure is determined according to the pore location, characterized by an abrupt failure and a significant decrease of ductility, while below that diameter, necking and fracture do not occur at the pore. The dynamic tensile mechanical behavior of the additively manufactured dense material was found to be similar to that of the conventional equivalent material, but the ductility to failure of the latter is observed to be higher.
Hydrogen–Air–Steam Deflagration Experiment Simulated Using Different Turbulent Flame-Speed Closure Models
Authors: Tadej Holler , Komen Ed M. J. , Ivo Kljenak
Published: January 2018

The paper presents the computational fluid dynamics (CFD) combustion modeling approach based on two combustion models. This modeling approach was applied to a hydrogen deflagration experiment conducted in a large-scale confined experimental vessel. The used combustion models were Zimont's turbulent flame-speed closure (TFC) model and Lipatnikov's flame-speed closure (FSC) model. The conducted simulations are aimed to aid identifying and evaluating the potential hydrogen risks in nuclear power plant (NPP) containment. The simulation results show good agreement with experiment for axial flame propagation using the Lipatnikov combustion model. However, substantial overprediction in radial flame propagation is observed using both combustion models, which consequently results also in overprediction of the pressure increase rate and overall combustion energy output. As assumed for a large-scale experiment without any turbulence inducing structures, the combustion took place in low-turbulence regimes, where the Lipatnikov combustion model, due to its inclusion of quasi-laminar source term, has advantage over the Zimont model.
Variable Material Properties Approach: A Review on Twenty Years of Progress
Authors: Faghih Sasan , Jahed Hamid , Behravesh Seyed Behzad
Published: January 2018

This paper provides a critical review of the advancements made in the application of the variable material properties (VMP) method over the past two decades. The VMP method was originally proposed in 1997 (Jahed and Dubey, 1997, ASME J. Pressure Vessel Technol., 119(3), pp. 264–273; Jahed et al., 1997, Int. J. Pressure Vessels Piping, 71(3), pp. 285–291) and further developed in 2001 (Parker, 2001, ASME J. Pressure Vessel Technol., 123(3), p. 271) as an elastoplastic method for the analysis of axisymmetric problems. The model was originally developed as a boundary value problem to predict the spatial distribution of stress. However, since 1997, it has been extended to include thermal effects to solve thermomechanical residual stresses; time domain to solve creep of disks and cylinders; finite deformation to solve cylinders under large strains; numerical solutions to make them more efficient; and asymmetric hardening behavior to accommodate nonslip deformation modes. These advancements, made over the past 20 years, are reviewed in this paper, and future trends and frontiers are discussed.
An Integration Method for Assessing the Operational Reliability of Underground Gas Storage in a Depleted Reservoir
Authors: Yu Weichao , Min Yuan , Huang Weihe , Wen Kai , Zhang Ye , Gong Jing
Published: January 2018

Underground gas storage (UGS), a key component of a natural gas pipeline network, can not only be used as an emergency gas source under a pipeline system failure situation but it is also available for seasonal peak shaving under pipeline system normal operation. Therefore, in order to meet the natural gas needs, it is of vital importance to safeguard the security of UGS operation and assess the reliability of UGS. The aim of the overall study is to develop an integration method for assessing operational reliability of UGS in a depleted reservoir under different injection-production scenarios, whereas existing studies only assess a single component or subsystem reliability. According to function zoning, UGS is separated into reservoir, well system, and surface system, and reservoir and surface system are connected through well system. The well system contains multiple injection/production wells. For the first step of the reliability assessment, the hydraulic calculation, including the gas injection process calculation and the gas production process calculation, is adopted to obtain the operational parameters of each component in UGS. Next, the reliability of the reservoir, injection/production well, and equipment in surface system is evaluated using operational parameters and a Monte Carlo approach. The reliability of the subsystem, such as the well system and surface system, is then calculated according to system reliability theory. Finally, operational reliability of UGS is obtained, which reflects the capacity of performing gas injection-production function. Two test cases are given to illustrate the integration method.
Silicon-carbon composites for lithium-ion batteries: A comparative study of different carbon deposition approaches
Authors: Alvarez Barragan Alejandro , Nava Giorgio , Wagner Nicole J. , Mangolini Lorenzo
Published: January 2018

Silicon-carbon composites, usually in the form of core–shell silicon-carbon nanostructures, have been widely investigated as potential candidates for the replacement of graphite in anodes for lithium ion batteries. Due to the availability of a broad range of precursors and protocols for the realization of a carbon shell, research groups active in this area have typically developed their own strategy to manufacture the desired structure. This is problematic since it does not allow for a direct comparison of the performance of similar structures during electrochemical cycling, and it does not provide a mechanistic insight into the factors affecting battery performance. In this work, the authors address this issue by directly comparing core–shell silicon-carbon nanostructures in which the carbon shell is achieved by carbonization of common polymers or by chemical vapor deposition (CVD) using acetylene as precursor. The samples have been prepared using exactly the same type of silicon particles as the active material, thus allowing a direct comparison between the different carbon shell growth approaches. The authors have found that the CVD process is preferable because it allows (1) a more direct tuning of the carbon-to-silicon ratio, (2) it leads to a conformal coating of the silicon particles with a carbon layer, and (3) it avoids exposing the particles to an oxidizing environment during the coating process. Anodes fabricated using the CVD-process nanoparticles clearly show better performance compared to those fabricated using a polymer carbonization approach.
Interaction of coadsorbed C and O atoms on W(100) surface: Implications of CO2 on the temperature-programmed desorption profile
Authors: Padama Allan Abraham B. , Albao Marvin A.
Published: January 2018

The authors study the adsorption and interaction of C and O atoms on the W(100) surface by performing density functional theory based calculations. Previous experimental works showed that C and O atoms exist on the surface when CO and CO2 dissociate. In this regard, the authors investigated the possibilities of forming O2 and CO2 from the coadsorbed species. Our results reveal that O2 is not stable as a molecule and will dissociate on the surface. CO2 formation on the other hand is accompanied by an activation barrier and is stable in a bent configuration. Its formation competes with CO dissociation and recombination. The authors will demonstrate through kinetic Monte Carlo simulations the implication of CO2 formation on the temperature programmed desorption profile and show that if stable and present in significant numbers, it would lead to erosion of the β2 peak. The authors therefore deduce that CO2 formation is most likely not a stable process and that CO2 formation and its subsequent decomposition are not significant in CO/W(100).
The QseG Lipoprotein Impacts the Virulence of Enterohemorrhagic Escherichia coli and Citrobacter rodentium and Regulates Flagellar Phase Variation in Salmonella enterica Serovar Typhimurium
Authors: Cameron Elizabeth A. , Gruber Charley C. , Ritchie Jennifer M. , Waldor Matthew K. , Sperandio Vanessa
Published: January 2018

The QseEF histidine kinase/response regulator system modulates expression of enterohemorrhagic
Escherichia coli
(EHEC) and
Salmonella enterica
serovar Typhimurium virulence genes in response to the host neurotransmitters epinephrine and norepinephrine.
qseG
, which encodes an outer membrane lipoprotein, is cotranscribed with
qseEF
in these enteric pathogens, but there is little knowledge of its role in virulence. Here, we found that in EHEC QseG interacts with the type III secretion system (T3SS) gate protein SepL and modulates the kinetics of attaching and effacing (AE) lesion formation on tissue-cultured cells. Moreover, an EHEC Δ
qseG
mutant had reduced intestinal colonization in an infant rabbit model. Additionally, in
Citrobacter rodentium
, an AE lesion-forming pathogen like EHEC, QseG is required for full virulence in a mouse model. In
S
. Typhimurium, we found that QseG regulates the phase switch between the two flagellin types, FliC and FljB. In an
S
. Typhimurium Δ
qseG
mutant, the phase-variable promoter for
fljB
is preferentially switched into the “on” position, leading to overproduction of this phase two flagellin. In infection of tissue-cultured cells, the
S
. Typhimurium Δ
qseG
mutant provokes increased inflammatory cytokine production versus the wild type;
in vivo
, in a murine infection model, the Δ
qseG
strain caused a more severe inflammatory response and was attenuated versus the wild-type strain. Collectively, our findings demonstrate that QseG is important for full virulence in several enteric pathogens and controls flagellar phase variation in
S
. Typhimurium, and they highlight both the complexity and conservation of the regulatory networks that control the virulence of enteric pathogens.
Ecology and Evolution of Chromosomal Gene Transfer between Environmental Microorganisms and Pathogens
Authors: Martínez José Luis
Published: January 2018

Inspection of the genomes of bacterial pathogens indicates that their pathogenic potential relies, at least in part, on the activity of different elements that have been acquired by horizontal gene transfer from other (usually unknown) microorganisms. Similarly, in the case of resistance to antibiotics, besides mutation-driven resistance, the incorporation of novel resistance genes is a widespread evolutionary procedure for the acquisition of this phenotype. Current information in the field supports the idea that most (if not all) genes acquired by horizontal gene transfer by bacterial pathogens and contributing to their virulence potential or to antibiotic resistance originate in environmental, not human-pathogenic, microorganisms. Herein I discuss the potential functions that the genes that are dubbed virulence or antibiotic resistance genes may have in their original hosts in nonclinical, natural ecosystems. In addition, I discuss the potential bottlenecks modulating the transfer of virulence and antibiotic resistance determinants and the consequences in terms of speciation of acquiring one or another of both categories of genes. Finally, I propose that exaptation, a process by which a change of function is achieved by a change of habitat and not by changes in the element with the new functionality, is the basis of the evolution of virulence determinants and of antibiotic resistance genes.
P09 ‘there’s no place like home’: reducing paediatric discharge steps
Authors: Emma Barbour , Catherine Collins , Niamh Mclister
Published: January 2018

Aim

To determine the efficiency of dispensing paediatric discharges at dispensary vs ward level.

Method

A data collection form was designed for use during a two-phase audit. During the first week of data collection, the turnaround time of dispensing discharges in the dispensary was collected. In the second week, the turnaround time of dispensing discharges at ward level on the paediatric ward was recorded.

The dispensary standard of a 60 min turnaround for medium priority discharges1 was used for both weeks. Medical, surgical and ENT prescriptions were all included in the audit.

Results

Information relating to 23 discharges was collected during week one at dispensary level. In week 2, 21 discharges were assessed.

When assessing the minimum and maximum time taken from when a patient was informed of their discharge to medications being given, there was a reduction of 98 min when completed at ward level for minimum time and 75 min for the maximum time.

The average turnaround time for dispensing prescriptions was 94 min at dispensary level and 26 min at ward level. Only 57% of discharges completed in the dispensary met the standard turnaround time of 60 min compared to 100% completed at ward level. Discharge prescription turnaround time was decreased by 72% when completed at ward level.

In total sixteen discharge steps were identified using the traditional dispensary based method for discharges. These ranged from the patient being told they can go home on the ward round to the prescription being written and sent to pharmacy, and finally returned to the ward for transfer to the patient.

The process of dispensing discharges at ward level enabled a reduction of 50% of the sixteen steps, subsequently expediting the discharge process.

Conclusion

When discharges were completed at ward level standards were met 100% of the time and a reduction in eight discharge steps was accomplished. Thus highlighting that a ward level dispensing service is necessary on the paediatric ward in this District General Hospital.

Reference

Wallace K. Prescription Tracker System (PTS). Patient services District General Hospital2014.