bluuebunny/crossref_metadata_2025 huggingface dataset:
Is it safe and effective to reduce the target anticoagulation range for patients with mechanical prosthetic aortic valves?
Authors: Mohamed Walid , Asimakopoulos George
Published: January 2020

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was ‘Is it safe and effective to reduce the target anticoagulation range for patients with mechanical aortic valves?’ Altogether 922 papers were found using the reported search, of which 7 represented the best evidence to answer the clinical question. Only studies that compared high (target international normalized ratio 2–3) versus low (target international normalized ratio <2–3) intensity anticoagulation were included. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that there is growing evidence for the reduction of the target anticoagulation range for patients with mechanical prosthetic aortic valves, especially bileaflet valves with presumed better haemodynamic properties. Several large randomized controlled trials and a meta-analysis have concluded that reducing the target international normalized ratio range (below the conventional range of 2–3) for mechanical aortic valves in patients with no thrombogenic risk factors produces less bleeding and does not increase thromboembolic events.
Surgical and endovascular treatment of a bilateral deep femoral artery aneurysm
Authors: Okugi Satoshi , Watanabe Kazumasa , Kunii Yoshifumi , Koide Masaaki
Published: January 2020

We report the rare case of a 68-year-old man with a bilateral deep femoral artery aneurysm. Right-sided rupture was treated via plug embolization of the right deep femoral artery and ligation. In the following year, Viabahn® stent grafts were placed in the left superficial femoral artery to relieve occlusion and in the left deep femoral artery to treat the left aneurysm. The postoperative course of the patient was uneventful.
Robust stabilization of non-linear non-autonomous control systems with periodic linear approximation
Authors: Slyn’ko V I , Tunç Cemil , Bivziuk V O
Published: January 2020

The paper deals with the problem of stabilizing the equilibrium states of a family of non-linear non-autonomous systems. It is assumed that the nominal system is a linear controlled system with periodic coefficients. For the nominal controlled system, a new method for constructing a Lyapunov function in the quadratic form with a variable matrix is proposed. This matrix is defined as an approximate solution of the Lyapunov matrix differential equation in the form of a piecewise exponential function based on partial sums of a W. Magnus series. A stabilizing control in the form of a linear feedback with a piecewise constant periodic matrix is constructed. This control simultaneously stabilizes the considered family of systems. The estimates of the domain of attraction of an asymptotically stable equilibrium state of a closed-loop system that are common for all systems are obtained. A numerical example is given.
Genus One Cobordisms Between Torus Knots
Authors: Feller Peter , Park JungHwan
Published: January 2020

We determine the pairs of torus knots that have a genus one cobordism between them, with one notable exception. This is done by combining obstructions using $\nu ^+$ from the Heegaard Floer knot complex and explicit constructions of cobordisms. As an application, we determine the pairs of torus knots related by a single crossing change. Also, we determine the pairs of Thurston–Bennequin number maximizing Legendrian torus knots that have a genus one exact Lagrangian cobordism, with one exception.
A comparative study between real-time PCR and loop-mediated isothermal amplification to detect carbapenemase and/or ESBL genes in Enterobacteriaceae directly from bronchoalveolar lavage fluid samples
Authors: Vergara A , Moreno-Morales J , Roca I , Pitart C , Kostyanev T , Rodriguez-Baño J , Goossens H , Marco F , Vila J
Published: January 2020

Objectives

To evaluate and compare the efficacy of real-time PCR (Xpert Carba-R) and loop-mediated isothermal amplification (Eazyplex® SuperBug CRE) for detecting carbapenemase carriage in Enterobacteriaceae directly from bronchoalveolar lavage (BAL).

Methods

Negative BAL samples were spiked with 21 well-characterized carbapenemase-producing Enterobacteriaceae strains to a final concentration of 102–104 cfu/mL. Xpert Carba-R (Cepheid, Sunnyvale, CA, USA), which detects five targets (blaKPC, blaNDM, blaVIM, blaOXA-48 and blaIMP-1), and the Eazyplex® SuperBug CRE system (Amplex-Diagnostics GmbH, Germany), which detects seven genes (blaKPC, blaNDM, blaVIM, blaOXA-48, blaOXA-181, blaCTXM-1 and blaCTXM-9), were evaluated for the detection of these genes directly from BAL samples.

Results

Xpert Carba-R showed 100% agreement with carbapenemase characterization by PCR and sequencing for all final bacteria concentrations. Eazyplex® SuperBug CRE showed 100%, 80% and 27% agreement with PCR and sequencing when testing 104, 103 and 102 cfu/mL, respectively. False negative results for Eazyplex® SuperBug CRE matched the highest cycle threshold values for Xpert Carba-R. Hands-on time for both assays was about 15 min, but Eazyplex® SuperBug CRE results were available within 30 min, whereas Xpert Carba-R took around 50 min.

Conclusions

We here describe the successful use of two commercial diagnostic tests, Xpert Carba-R and Eazyplex® SuperBug CRE, to detect bacterial carbapenem resistance genes directly in lower respiratory tract samples. Our results could be used as proof-of-concept data for validation of these tests for this indication.
Population Bottlenecks Strongly Influence the Evolutionary Trajectory to Fluoroquinolone Resistance in Escherichia coli
Authors: Garoff Linnéa , Pietsch Franziska , Huseby Douglas L , Lilja Tua , Brandis Gerrit , Hughes Diarmaid
Published: January 2020

Experimental evolution is a powerful tool to study genetic trajectories to antibiotic resistance under selection. A confounding factor is that outcomes may be heavily influenced by the choice of experimental parameters. For practical purposes (minimizing culture volumes), most experimental evolution studies with bacteria use transmission bottleneck sizes of 5 × 106 cfu. We currently have a poor understanding of how the choice of transmission bottleneck size affects the accumulation of deleterious versus high-fitness mutations when resistance requires multiple mutations, and how this relates outcome to clinical resistance. We addressed this using experimental evolution of resistance to ciprofloxacin in Escherichia coli. Populations were passaged with three different transmission bottlenecks, including single cell (to maximize genetic drift) and bottlenecks spanning the reciprocal of the frequency of drug target mutations (108 and 1010). The 1010 bottlenecks selected overwhelmingly mutations in drug target genes, and the resulting genotypes corresponded closely to those found in resistant clinical isolates. In contrast, both the 108 and single-cell bottlenecks selected mutations in three different gene classes: 1) drug targets, 2) efflux pump repressors, and 3) transcription-translation genes, including many mutations with low fitness. Accordingly, bottlenecks smaller than the average nucleotide substitution rate significantly altered the experimental outcome away from genotypes observed in resistant clinical isolates. These data could be applied in designing experimental evolution studies to increase their predictive power and to explore the interplay between different environmental conditions, where transmission bottlenecks might vary, and resulting evolutionary trajectories.
Double-Tonic Complexes in Rock Music
Authors: Nobile Drew
Published: January 2020

Most analysts consider a song either to be in a single key or to exhibit competition or ambiguity among multiple possible keys. This article proposes an alternative in which two keys combine to create a coherent, stable tonality. I adapt Robert Bailey’s concept of the “double-tonic complex” to demonstrate that in many rock songs, relative major and minor keys coexist with neither superior to the other and no conflict between them. These songs are not quite in two keys at once, but rather each component key represents a different incarnation of a single, more abstract tonality encompassing them both. The prolonged generative tonic of such a structure is a four-note sonority built from the union of the two tonic triads; this sonority often—but not always—appears as a surface chord at structurally important moments.
Options Trading Costs Are Lower than You Think
Authors: Muravyev Dmitriy , Pearson Neil D
Published: January 2020

Conventional estimates of the costs of taking liquidity in options markets are large. Nonetheless, options trading volume is high. We resolve this puzzle by showing that options price changes are predictable at high frequency, and many traders time executions by buying (selling) when the option fair value is close to the ask (bid). Effective spreads of traders who time executions are less than 40% of the size of conventional measures, and the overall average effective spread is one-quarter smaller than conventional estimates. Price impact measures are also affected. These findings alter conclusions about the after-cost profitability of options trading strategies.
Financial Inclusion, Human Capital, and Wealth Accumulation: Evidence from the Freedman’s Savings Bank
Authors: Stein Luke C D , Yannelis Constantine
Published: January 2020

This paper studies how access to financial services among a previously unbanked group affects human capital, labor market, and wealth outcomes. We use novel data from the Freedman’s Savings Bank—created following the American Civil War to serve free Blacks—employing an instrumental variables strategy exploiting the staggered rollout of bank branches. Families with accounts are more likely to have children in school, be literate, work, and have higher occupational income, business ownership, and real estate wealth. Placebo effects are not present using planned but unbuilt branches, or for Whites, suggesting significant positive effects of financial inclusion.
The last chance to pass the ball: investigating the role of temporal expectation and motor resonance in processing temporal errors in motor actions
Authors: Pedullà Ludovico , Gervasoni Elisa , Bisio Ambra , Biggio Monica , Ruggeri Piero , Avanzino Laura , Bove Marco
Published: January 2020

Humans can acquire information on others’ motor outputs (action prediction) and intentions (action understanding) according to their individual motor repertoire and to the detected gesture’s features (e.g. temporal patterns). We aimed at dissociating between action prediction and action understanding abilities in soccer players and novices observing soccer action videos including correct timing pass (CTP) or delayed pass (DP). First, we used an occluding paradigm to evaluate participants’ ability to predict the correct time to pass the ball. Although soccer players showed reduced reaction times, all subjects showed a similar pattern of performance: during DP observation, responses appeared delayed with respect to the other conditions but anticipated with respect to the observed DP. In a separate experiment, we investigated the ability to recognize CTP vs DP and the modulation of primary motor cortex (M1) excitability associated to video observation. Only soccer players showed selective modulation of M1 according to the plausibility of the observed action, with increased excitability during the observation of the CTP and in a phase preceding the DP. In conclusion, action prediction ability seems to be independent from the individual motor repertoire. By contrast, only subjects with previously acquired sensorimotor skills are able to infer the observed action’s long-term intention.
Prospect patents, data markets, and the commons in data-driven medicine: Openness and the political economy of intellectual property rights
Authors: Sideri Katerina
Published: January 2020

Scholars who point to political influences and the regulatory function of patent courts in the USA have long questioned the courts’ subjective interpretation of what ‘things’ can be claimed as inventions. The present article sheds light on a different but related facet: the role of the courts in regulating knowledge production. I argue that the recent cases decided by the US Supreme Court and the Federal Circuit, which made diagnostics and software very difficult to patent and which attracted criticism for a wealth of different reasons, are fine case studies of the current debate over the proper role of the state in regulating the marketplace and knowledge production in the emerging information economy. The article explains that these patents are prospect patents that may be used by a monopolist to collect data that everybody else needs in order to compete effectively. As such, they raise familiar concerns about failure of coordination emerging as a result of a monopolist controlling a resource such as datasets that others need and cannot replicate. In effect, the courts regulated the market, primarily focusing on ensuring the free flow of data in the emerging marketplace very much in the spirit of the ‘free the data’ language in various policy initiatives, yet at the same time with an eye to boost downstream innovation. In doing so, these decisions essentially endorse practices of personal information processing which constitute a new type of public domain: a source of raw materials which are there for the taking and which have become most important inputs to commercial activity. From this vantage point of view, the legal interpretation of the private and the shared legitimizes a model of data extraction from individuals, the raw material of information capitalism, that will fuel the next generation of data-intensive therapeutics in the field of data-driven medicine.
Mapping and Analysis of US State and Urban Local Sodium Reduction Laws
Authors: Sloan Arielle A. , Keane Thomas , Pettie Jennifer Rutledge , Bhuiya Aunima R. , Taylor Lauren N. , Bates Marlana , Bernard Stephanie , Akinleye Fahruk , Gilchrist Siobhan
Published: January 2020

Context:

Excessive sodium consumption contributes to high blood pressure, which is a risk factor for cardiovascular disease.

Objectives:

To (1) identify state and urban local laws addressing adult or general population sodium consumption in foods and beverages and (2) align findings to a previously published evidence classification review, the Centers for Disease Control and Prevention Sodium Quality and Impact of Component (QuIC) evidence assessment.

Design:

Systematic collection of sodium reduction laws from all 50 states, the 20 most populous counties in the United States, and the 20 most populous cities in the United States, including Washington, District of Columbia, effective on January 1, 2019. Relevant laws were assigned to 1 or more of 6 interventions: (1) provision of sodium information in restaurants or at point of purchase; (2) consumer incentives to purchase lower sodium foods; and provision of lower sodium offerings in (3) workplaces, (4) vending machines, (5) institutional meal services, and (6) grocery, corner, and convenience stores. The researchers used Westlaw, local policy databases or city Web sites, and general nutrition policy databases to identify relevant laws.

Results:

Thirty-nine sodium reduction laws and 10 state laws preempting localities from enacting sodium reduction laws were identified. Sodium reduction laws were more common in local jurisdictions and in the Western United States. Sodium reduction laws addressing meal services (n = 17), workplaces (n = 12), labeling (n = 13), and vending machines (n = 11) were more common, while those addressing grocery stores (n = 2) or consumer incentives (n = 6) were less common. Laws with high QuIC evidence classifications were generally more common than laws with low QuIC evidence classifications.

Conclusions:

The distribution of sodium laws in the US differed by region, QuIC classification, and jurisdiction type, indicating influence from public health and nonpublic health factors. Ongoing research is warranted to determine how the strength of public health evidence evolves over time and how those changes correlate with uptake of sodium reduction law.
Putting Policy Into Practice: School-Level Compliance With and Implementation of State Concussion Laws
Authors: Sullivan Lindsay , Harvey Hosea H. , Smith Gary A. , Yang Jingzhen
Published: January 2020

Context:

Each year, approximately 2 million US children 18 years or younger sustain a concussion, a type of mild traumatic brain injury (TBI). Concussions can have detrimental effects on physical, cognitive, emotional, or sleep health.

Policy:

Between 2009 and 2014, all 50 US states and Washington, District of Columbia, enacted state concussion laws aimed to increase awareness about concussion and reduce the prevalence and severity of this injury. Most state laws include the following core tenets: (1) immediate removal from play after an actual or suspected concussion; (2) medical clearance before an athlete can return to play (RTP); and (3) concussion education for athletes, parents, and coaches.

Implementation:

State concussion laws allow for substantial interpretation at the school level, resulting in considerable variation in the content of school written concussion policies and the level of implementation of state law requirements at the school level.

Evaluation:

We assessed the degree of high school written concussion policy compliance with the respective state law and examined the relationship between concussion policy compliance and school-level implementation of concussion laws. Seventy-one school officials completed a semistructured telephone interview and submitted their school's written concussion policy. Of the 71 policies analyzed, most complied with the removal-from-play, RTP, and concussion education tenets (90.1%, 97.2%, and 76.1%, respectively). The majority of participants reported that their school implemented the removal-from-play (91.5%), RTP (93.0%), and concussion education (80.6%) tenets well or very well. No significant relationships were found between researcher-rated school policy compliance and school-reported implementation of state law requirements at the school level.

Discussion:

Our findings suggest that most participating schools complied with their state concussion law and implemented law requirements well or very well. Future studies should identify facilitators and barriers to the implementation of state concussion laws at the school level.
Effects of rhein on bile acid homeostasis in rats
Authors: Xian Zhong , Tian Jingzhuo , Wang Lianmei , Zhang Yushi , Han Jiayin , Deng Nuo , Liu Suyan , Zhao Yong , Li Chunying , Yi Yan , Wang Dunfang , Meng Jing , Pan Chen , Liang Aihua
Published: January 2020

Rhein, the active ingredient of rhubarb, a medicinal and edible plant, is widely used in clinical practice. In this work, we investigated the alterations of 14 bile acids and hepatic transporters after rats were administered rhein for 5 consecutive weeks. There was no obvious injury to the liver and kidney, and there were no significant changes in biochemical indicators. However, 1,000 mg/kg rhein increased the liver total bile acid (TBA) levels, especially taurine-conjugated bile acids (t-CBAs), inhibited the expression of Farnesoid X receptor (FXR) and (bile salt export pump) BSEP mRNA, and upregulated the expression of (cholesterol 7α-hydroxylase) CYP7A1 mRNA. Rhein close to the clinical dose reduced the amounts of TBAs, especially unconjugated bile acids (UCBAs), and elevated the expression of FXR and multidrug resistance-associated protein 3 (Mrp3) mRNA. These results denote that rhein is not toxic and is safe to use at a reasonable dose and timing.
Systematic Normalization with Multiple Housekeeping Genes for the Discovery of Genetic Dependencies in Cancer
Authors: Bonham-Carter Oliver , Thu Yee Mon
Published: January 2020

Cancer results from complex interactions between genes that are misregulated. Although our understanding of the contribution of single genes to cancer is expansive, the interplay between genes in the context of this devastating disease remains to be understood. Using the Genomic Data Commons Data Portal through National Cancer Institute, we randomly selected ten data sets of breast cancer gene expression, acquired by RNA sequencing to be subjected to a computational method for the exploration of genetic interactions at a large scale. We focused on genes that suppress genome instability (GIS genes) since function or expression of these genes is often altered in cancer.

In this paper, we show how to discover pairs of genes whose expressions demonstrate patterns of correlation. To ensure an inter-comparison across data sets, we tested statistical normalization approaches derived from the expression of randomly selected single housekeeping genes, or from the average of three. In addition, we systematically selected ten housekeeping genes for the purpose of normalization. Using normalized expression data, we determinedR2values from linear models for all possible pairs of GIS genes and presented our results using heatmaps.

Despite the heterogeneity of data, we observed that multiple gene normalization revealed more consistent correlations between pairs of genes, compared to using single gene expressions. We also noted that multiple gene normalization using ten genes outperformed normalization using three randomly selected genes. Since this study uses gene expression data from cancer tissues and begins to address the reproducibility of correlation between two genes, it complements other efforts to identify gene pairs that co-express in cancer cell lines. In the future, we plan to define consistent genetic correlations by using gene expression data derived from different types of cancer and multiple gene normalization.

CCS CONCEPTS

Applied computing →Computational biology.

ACM Reference Format

Oliver Bonham-Carter and Yee Mon Thu. 2019. Systematic Normalization with Multiple Housekeeping Genes for the Discovery of Genetic Dependencies in Cancer. InNiagara Falls, New York.ACM, New York, NY, USA, 10 pages. https://doi.org/10.1145/nnnnnnn.nnnnnnn
Mutational effects on carbapenem hydrolysis of YEM-1, a new sub-class B2 metallo-β-lactamase fromYersinia mollaretii
Authors: Mercuri P. S. , Esposito R. , Blétard S. , Di Costanzo S. , Perilli M. , Kerff F. , Galleni M.
Published: January 2020

The analysis of the genome sequence ofYersinia mollaretii(Y. mollaretii) ATCC 43969 indicates the presence of theblaYEMgene coding for YEM-1, a putative subclass B2 metallo-β-lactamase. The objectives of our work were to produce, purify and complete the kinetic characterization of YEM-1. Compared to the known subclass B2 metallo–β-lactamases, YEM-1 displayed a narrowest substrate profile since it is only able to hydrolyse imipenem with a high catalytic efficiency but not all the other carbapenems tested such as biapenem, meropenem, doripenem and ertapenem. A possible explanation of this peculiar activity profile is the presence of tyrosine 67 (loop L1), threonine 156 (loop L2) and serine 236 (loop L3) respectively. We showed that the substitution of Y67 broadened the activity profile of the enzyme for all carbapenems but still displayed a poor activity toward the other β-lactam classes.
LRRK2 and Rab10 Coordinate Macropinocytosis to Mediate Immunological Responses in Phagocytes
Authors: Liu Zhiyong , Xu Enquan , Zhao Hien Tran , Cole Tracy , West Andrew B.
Published: January 2020

Genetic variation inLRRK2associates with susceptibility to Parkinson’s disease, Crohn’s disease, and mycobacteria infection, with high expression of LRRK2, and the LRRK2 kinase substrate Rab10, in phagocytic cells in the immune system. In mouse and human primary monocyte-derived macrophages, dendritic cells, and microglia-like cells, we find that Rab10 specifically regulates a specialized form of endocytosis known as macropinocytosis, without affecting phagocytosis or clathrin-mediated endocytosis. LRRK2 phosphorylates cytoplasmic PI(3,4,5)P3-positive GTP-Rab10 early macropinosomes, before EEA1 and Rab5 recruitment occurs. Macropinosome cargo in macrophages includes CCR5, CD11b, and MHCII, with LRRK2-phosphorylation of Rab10 potently blocking EHBP1L1-mediated recycling tubules and cargo turnover. EHBP1L1 over-expression competitively inhibits LRRK2-phosphorylation of Rab10, mimicking the effects of LRRK2 kinase inhibition in promoting cargo recycling. Both Rab10 knockdown and LRRK2 kinase inhibition potently suppresses the maturation of macropinosome-derived CCR5-loaded signaling endosomes important for CCL5-induced AKT-activation and chemotaxis. These data support a novel axis in the endolysosomal system whereby LRRK2-mediated Rab10 phosphorylation stalls vesicle fast-recycling to promote PI3K-AKT signal transduction.
The Effect of Kinship in Re-identification Attacks Against Genomic Data Sharing Beacons
Authors: Ayoz Kerem , Aysen Miray , Ayday Erman , Cicek A. Ercument
Published: January 2020

Motivation

Big data era in genomics promises a breakthrough in medicine, but sharing data in a private manner limits the pace of field. Widely accepted “genomic data-sharing beacon” protocol provides a standardized and secure interface for querying the genomic datasets. The data is only shared if the desired information (e.g., a certain variant) exists in the dataset. Various studies showed that beacons are vulnerable to re-identification (or membership inference) attacks. As beacons are generally associated with sensitive phenotype information, re-identification creates a significant risk for the participants. Unfortunately, proposed countermeasures against such attacks have failed to be effective, as they do not consider the utility of beacon protocol.

Results

In this study, for the first time, we analyze the mitigation effect of the kinship relationships among beacon participants against re-identification attacks. We argue that having multiple family members in a beacon can garble the information for attacks since a substantial number of variants are shared among kinrelated people. Using family genomes from HapMap and synthetically-generated datasets, we show that having one of the parents of a victim in the beacon causes (i) significant decrease in the power of attacks and (ii) substantial increase in the number of queries needed to confirm an individual’s beacon membership. We also show how the protection effect attenuates when more distant relatives, such as grandparents are included alongside the victim. Furthermore, we quantify the utility loss due adding relatives and show that it is smaller compared to flipping based techniques.
Uncanny similarity of unique inserts in the 2019-nCoV spike protein to HIV-1 gp120 and Gag
Authors: Pradhan Prashant , Pandey Ashutosh Kumar , Mishra Akhilesh , Gupta Parul , Tripathi Praveen Kumar , Menon Manoj Balakrishnan , Gomes James , Vivekanandan Perumal , Kundu Bishwajit
Published: January 2020

This paper has been withdrawn by its authors. They intend to revise it in response to comments received from the research community on their technical approach and their interpretation of the results. If you have any questions, please contact the corresponding author.
Two novel polymorphic forms of iron-chelating agent deferiprone
Authors: Rajendrakumar Satyasree , Durga Anuja Surampudi Venkata Sai , Nanubolu Jagadeesh Babu , Balasubramanian Sridhar
Published: January 2020

Thalassemia is a genetic blood disorder requiring life-long blood transfusions. This process often results in iron overload and can be treated by an iron-chelating agent, like deferiprone (3-hydroxy-1,2-dimethylpyridin-4-one), C7H9NO2, in an oral formulation. The first crystal structure of deferiprone, (Ia), was reported in 1988 [Nelson et al. (1988). Can. J. Chem.
66, 123–131]. In the present study, two novel polymorphic forms, (Ib) and (Ic), of deferiprone were identified concomitantly with polymorph (Ia) during the crystallization experiments. Polymorph (Ia) was redetermined at low temperature for comparison of the structural features and lattice energy values with polymorphs (Ib) and (Ic). Polymorph (Ia) crystallized in the orthorhombic space group Pbca, whereas both polymorphs (Ib) and (Ic) crystallized in the monoclinic space group P21/c. The asymmetric units of (Ia) and (Ib) contain one deferiprone molecule, while polymorph (Ic) has three crystallographically independent molecules (A, B and C). All three polymorphs have similar hydrogen-bonding features, such as an R
2
2(10) dimer formed by O—H...O hydrogen bonds, an R
4
3(20) tetramer formed by C—H...O hydrogen bonds and π–π interactions, but the polymorphs differ in their molecular arrangements in the solid state and are classified as packing polymorphs. O—H...O and C—H...O hydrogen bonds lead to the formation of two-dimensional hydrogen-bonded parallel sheets which are interlinked by π–π stacking interactions. In the three-dimensional crystal packing, the deferiprone molecules were aggregated as corrugated sheets in polymorphs (Ia) and (Ic), whereas in polymorph (Ib), they were aggregated as a square-grid network. The characteristic crystalline peaks of polymorphs (Ia), (Ib) and (Ic) were established through powder X-ray diffraction analysis. The Rietveld analysis was also performed to estimate the contribution of the polymorphs to the bulk material.
Poly[[tetradecakis(μ-propionato)heptabarium] propionic acid monosolvate tetrahydrate]
Authors: Samolová Erika , Fábry Jan
Published: January 2020

The title compound, {[Ba7(C3H5O2)14]·0.946C3H6O2·4H2O}n, is represented by a metal–organic framework structure that is held together by Ba—O—Ba bonds, as well as by O—H...O hydrogen bonds of moderate strength. The structure comprises of four independent Ba2+cations (one of which is situated on a twofold rotation axis), seven independent propionate and two independent water molecules. The bond-valence sums of all the cations indicate a slight overbonding. There is also an occupationally, as well as a positionally disordered propionic acid molecule present in the structure. Its occupation is slightly lower than the full occupation while the disordered molecules occupy two positions related by a rotation about a twofold rotation axis. In addition, the methyl group in the symmetry-independent propionic acid molecule is also disordered, and occupies two positions. Each propionic acid molecule coordinates to just one cation from a pair of symmetry-equivalent Ba2+sites and is simultaneously bonded by an O—H...Opropionatehydrogen bond. This means that on a microscopic scale, the coordination number of the corresponding Ba2+site is either 9 or 10. The methyl as well as hydroxy hydrogen atoms of the disordered propionic acid molecule were not determined.
Benzene-1,2-diaminium bis(4-methylbenzene-1-sulfonate)
Authors: Narvekar Kedar U. , Srinivasan Bikshandarkoil R.
Published: January 2020

The structure of the title salt, C6H10N2
2+·2C7H7O3S−, consists of a unique benzene-1,2-diaminium dication charge balanced by a pair of crystallographically independent 4-methylbenzene-1-sulfonate anions. The cations and anions are interlinked by several N—H...O hydrogen bonds.
Redetermination of the crystal structure of caesium tetrafluoridobromate(III) from single-crystal X-ray diffraction data
Authors: Malin Artem V. , Ivlev Sergei I. , Ostvald Roman V. , Kraus Florian
Published: January 2020

Caesium tetrafluoridobromate(III), CsBrF4, was crystallized in form of small blocks by melting and recrystallization. The crystal structure of CsBrF4 was redetermined from single-crystal X-ray diffraction data. In comparison with a previous study based on powder X-ray diffraction data [Ivlev et al. (2013). Z. Anorg. Allg. Chem. 639, 2846–2850], bond lengths and angles were determined with higher precision, and all atoms were refined with anisotropic displacement parameters. It was confirmed that the structure of CsBrF4 contains two square-planar [BrF4]− anions each with point group symmetry mmm, and a caesium cation (site symmetry mm2) that is coordinated by twelve fluorine atoms, forming an anticuboctahedron. CsBrF4 is isotypic with CsAuF4.
Effect of cerium nitrate and salicylic acid on the titanium–zirconium chemical conversion coating of 6061 aluminum alloy
Authors: Wang Xiaobo , Zhan Wen , Gui Boyi
Published: January 2020

Purpose

The purpose of this paper is to develop a chrome-free and phosphorus-free chemical conversion coating with good corrosion resistance, a novel chemical conversion coating was prepared by adding cerium nitrate hexahydrate and salicylic acid in the treatment solution containing titanium/zirconium ions on 6061 aluminum alloy.

Design/methodology/approach

Compared with the AA6061 aluminum alloy matrix, the self-corrosion potential of the conversion coating is significantly positively shifted, the self-corrosion current density is greatly reduced and its corrosion resistance is significantly improved. Morphology and composition of the conversion coatings were observed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The microdomain structure of conversion coatings at different formation stages was analyzed by electron probe microanalyzer.

Findings

An optimized preparation technique of titanium–zirconium chemical conversion coating for AA6061 aluminum alloy is obtained: H2TiF6 4 mL/L, H2ZrF6 0.4 mL/L, salicylic acid 0.35 g/L, Ce(NO3)3·6H2O 0.14 g/L, reaction temperature 30°C, reaction time 120 s and pH 4.0.

Originality/value

The coating forms on the Al(Fe)Si intermetallic compound, and Ce3+ is preferentially adsorbed on the intermetallic compound. The hydrolysis of Ce3+ causes the local pH of the solution to decrease, which promotes matrix dissolution and charge migration. As the microanode/microcathode reaction occurs, the local pH of the solution increases, and Al2O3/ZrO2/TiO2 begins to deposit on the surface of the metal substrate.
Enhancement of low-voltage ride-through capability of permanent magnet synchronous generator wind turbine by applying state-estimation technique
Authors: Shahriari Sayyed Ali Akbar , Mohammadi Mohammad , Raoofat Mahdi
Published: January 2020

Purpose

The purpose of this study is to propose a control scheme based on state estimation algorithm to improve zero or low-voltage ride-through capability of permanent magnet synchronous generator (PMSG) wind turbine.

Design/methodology/approach

Based on the updated grid codes, during and after faults, it is necessary to ensure wind energy generation in the network. PMSG is a type of wind energy technology that is growing rapidly in the network. The control scheme based on extended Kalman filter (EKF) is proposed to improve the low voltage ride-through (LVRT) capability of the PMSG. In the control scheme, because the state estimation algorithm is applied, the requirement of DC link voltage measurement device and generator speed sensor is removed. Furthermore, by applying this technique, the extent of possible noise on measurement tools is reduced.

Findings

In the proposed control scheme, zero or low-voltage ride-through capability of PMSG is enhanced. Furthermore, the requirement of DC link voltage measurement device and generator speed sensor is removed and the amount of possible noise on the measurement tools is minimized. To evaluate the ability of the proposed method, four different cases, including short and long duration short circuit fault close to PMSG in the presence and absence of measurement noise are studied. The results confirm the superiority of the proposed method.

Originality/value

This study introduces EKF to enhance LVRT capability of a PMSG wind turbine.
Repositioning a country for global manufacturing competitiveness: a case of South Africa
Authors: Gates Gareth Earle , Adetunji Olufemi
Published: January 2020

Purpose

This study aims to develop an artifact to measure the level of manufacturing competitiveness of a country in the global context and provide a suitable interpretation mechanism for the measured values, and to provide prescriptive solution where necessary so that the country can develop an actionable plan of program to move from the current level of global competitiveness to another such that they could provide more economic opportunities for their citizenry.

Design/methodology/approach

A manufacturing competitive index (MCI) was developed which includes relevant variables to capture a country’s manufacturing activity level in an economy with a balanced perspective. Reliable international sources were used. Ward algorithm was used to identify clear clusters of performance upon which competitive gaps were measured and improvement projects were identified and prioritized to obtain the best value for cluster transitional plan.

Findings

This study shows that the case country is not doing as well as it wants to believe, even when the relevant technology import measures were included in the expanded metric, but also, the next level of competitiveness is achievable within the national budget if proper prioritization is done.

Originality/value

The paper presents a cocktail of indexes that is more exhaustive of MCI, including both research capacity and technology import variables. It also uses clustering mechanism to provide a proper context to interpret the MCI scores in the context of peer nations. It presents a gap determination methodology and shows how priority projects could be logically selected to close measured gaps based on anticipated value from budget expenses
Public libraries and goal 16 of the SDGS in Cameroon: which actors for a national policy?
Authors: Ngo Kobhio Balôck Louise Lutéine
Published: January 2020

Purpose

This paper aims to investigate how public libraries in Cameroon contribute to the achievement of goal 16 of the Sustainable Development Goals, which is “peace, justice and strong institutions”.

Design/methodology/approach

The methodology used is observation, talks with the librarians of public libraries from different regions of the country. Authorities in charge of this domain in Cameroon, that is the Ministry of Arts and Culture. Statistics from these different actors have been collected and used for the study, as well as those available through the National Institute of statistics.

Findings

The participation of public libraries in the implementation of goal 16 in Cameroon is remarkable, even if they lack substantial budgets for the achievement of their goals and rely partly on donations. The increasingly widespread use of information and communication technologies, as well as certain paying activities, partly compensates for this lack. Democracy, living together, access to employment and self-employment through the dissemination of information and animation are effective tools that public libraries implement. Users from different origins can gather and discuss freely on national issues. Public libraries are sometimes involved as mediators in the resolution of some social conflicts.

Practical implications

In a period were seeking peace, justice and strong institutions is one of the main national issues discussed in Cameroon, the study provides more visibility to both the authorities and the potential users on the important role played by public libraries in the resolution of national issues.

Originality/value

The study determines the different actors of a national policy in the framework of the creation, and the promotion of the public libraries and their respective roles for a more concerted and better-oriented action.
Career cooperation, coordination, compatibility and co-working
Authors: Shortland Susan
Published: January 2020

Purpose

The purpose of this study is to examine how female expatriates mobilise couples’ dual-career coordination strategic choices to achieve their own and their partners’ desired career goals.

Design/methodology/approach

This qualitative research is based upon in-depth interviews with 20 dual-career female expatriates working in two case study oil and gas organisations.

Findings

Female expatriates use a series of tactics ranging from cooperation in maintaining a dual-career hierarchy, through to coordinating aspects of their own and their partners’ assignments, undertaking compatible industry roles and co-working (working together in the same organisation) to attempt to achieve a greater egalitarian international dual-career strategic outcome.

Research limitations/implications

This case analysis was based on a relatively small sample of female expatriates in heterosexual relationships working in oil and gas exploration. Further research in different sectors, with larger samples, and with male expatriates is also needed.

Practical implications

Employers should minimise periods of separation by focussing on coordinated assignment timings for both partners, facilitate suitable employment for both partners who wish to work abroad, and prioritise securing partner work visas.

Social implications

The inability to pursue desired dual-careers together while undertaking international assignments can be detrimental to couples’ relationships, potentially leading to unwillingness to expatriate and thereby deliver necessary skills in the host country.

Originality/value

The originality lies in identifying the tactics women use to enact dual-career coordination strategies, including coordinating assignment timings and locations to reduce separation and pursuing compatible roles to achieve egalitarian career and relationship outcomes. While women expected co-working in the same firm to facilitate dual-career mobility, its career outcomes were disappointing.
Service breakdown prevention
Authors: Woodside Arch G. , Caldwell Marylouise , Calhoun Jennifer Rebecca
Published: January 2020

Purpose

This study defines service breakdowns, service breakdown prevention, and “servicide” as they relate to service-dominant logic. The study reviews relevant relevant literature on these three topics. This study categorizes real-life examples into five levels of dramatic turns toward service degradations and breakdowns that range from customer being aware but not mentioning service inadequacy to the service breakdown resulting in death of the customer or service provider. Taking initial steps in developing dramatic turn theory and improving the practice of service breakdown prevention are the major contributions of this study.

Design/methodology/approach

This study is a conceptual contribution that includes a dramatic turn role-playing exercise (at category 4 among five categories of dramatic turns for pedagogical/on-site enacting/practicing and training of service professionals. The study emphasizes and shows how to create and enact role-playing scenarios to increase requisite variety, provide training modules and increase skills/expertise in service enactment contexts.

Findings

Before explicit reviewing of the dramatic-turn performances, some of the participants as actors as well as audience members in role-play dramatic turns were quick to blame the customer behavior as the principal cause for the service breakdown. The study’s exposition stresses prevention of negative dramatic turns follows from experiencing and coaching a wide variety of customer and server interactions – achieving “richness” in enactments.

Research limitations/implications

Research on service breakdown prevention needs to include field experiments on the efficacy of training programs for effective management of dramatic turns.

Practical implications

Training of service workers and service managers in experiencing/participating in dramatic turns is likely to be beneficial in reducing the severe adverse outcomes and unintended consequences of service breakdowns. Prevention, not only service failure recovery, needs to be an explicit focus in hospitality management training and assessment.

Social implications

This study suggests tools and procedures to reduce the instances of the need for service breakdown recoveries.

Originality/value

The study calls attention and contributes a way forward in managing dramatic turns in hospitality service contexts. The study provides a nascent configurational theoretical foundation of dramatic-turn propositions. Given the severity of financial costs and loss of brand/firm reputation following the occurrence of extreme dramatic turns, a research focus on service breakdown prevention is necessary.
The mediating roles of gratitude and obligation to link employees’ social exchange relationships and prosocial behavior
Authors: Kim Haemi , Qu Hailin
Published: January 2020

Purpose

This study aims to investigate the psychological mechanisms underlying hospitality employees’ social exchange relationships at work by applying the social aspects of work and the social exchange theory.

Design/methodology/approach

MTurk was used for conducting a cross-sectional questionnaire survey, targeting frontline employees who were working in full-service restaurants. Descriptive statistic, confirmatory factor analysis and structural equation modeling were performed.

Findings

Customer-employee exchange had a positive relationship with gratitude. Moreover, gratitude was positively associated with both role-prescribed customer service and extra-role customer service. Leader-member exchange and coworker exchange were positively related to obligation. Obligation had positive association with both role-prescribed customer service and extra-role customer service. The mediating effects of gratitude and obligation were statistically significant.

Research limitations/implications

Employees’ social exchange relationship with customers promotes prosocial behaviors by arousing gratitude in them. Moreover, their social exchange relationships with supervisors and coworkers lead to prosocial behaviors by provoking obligation from them.

Originality/value

This research shows the importance of the social aspects of work to contribute to employees’ prosocial behavior in the hospitality industry. Moreover, it proves the critical roles of emotions to guide employees’ decisions about social exchange.
Financial development threshold, private capital inflows and economic growth
Authors: Anetor Friday Osemenshan
Published: January 2020

Purpose

This study aims to examine the relationship between private capital inflows, financial development and economic growth in 28 sub-Saharan African (SSA) countries between the periods 1995 and 2017.

Design/methodology/approach

The study used a secondary source of data obtained from the world development indicator (WDI) and used the system generalized method of moments (SGMM) and dynamic panel threshold regression to analyze the data.

Findings

The study found that foreign direct investment has a negative and significant impact on the economic growth of SSA. The study also found that portfolio investment has a positive impact on economic growth but it is statistically insignificant. However, when portfolio investment interacted with financial development, it became positive and statistically significant presupposing that financial development is a necessary condition for portfolio investment to exert impact on economic growth. Further, the study showed that the interaction of foreign direct investment with financial development has a negative and significant effect on economic growth. Finally, the study found the minimum threshold of financial development at 42.66 per cent.

Practical implications

Policymakers in SSA should be cautious and critical in the kind of foreign direct investment they attract as the open door policy to attract all kinds of foreign direct investment would not bring about the desired result. Also, policymakers in the region should develop and implement policies that would deepen and strengthen the financial system to foster the development of the country’s financial sector and accelerate economic growth.

Originality/value

The contribution of the study lies in establishing a minimum threshold of financial development; thus, providing a clear-cut direction for policymakers in SSA countries in their pursuit of financial development and economic growth.