bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementation of Public Procurement Act and Government Performance: Evidence from Nigeria
Authors: Florence F. Oyebamiji,
Published: March 2019

This study examines the influence of implementation of public procurement Act on government performance in Nigeria. Specifically, the study determines the extent of compliance with the Public Procurement Act, identifies factors affecting compliance with the Public Procurement Act and also examines the influence of implementation of the Public Procurement Act on government performance. Judgmental sampling technique was used to select 20 Procurement Officers in Ministries, Departments and Agencies, and Local Government Areas; 20 Accounting Officers from Permanent Secretaries, Heads of Agencies and Parastatal Organizations; 20 contractors, 20 Professionals-Quantity surveyor, 20 architects and engineers, and 20 Lawyers totaling 120 respondents as sample size for the study. Structured questionnaires designed for the study were used to collect the data. Analyzed data was performed with the aid of descriptive statistics and regression analysis. The result establishes that public entities comply with the public procurement Act 2007, but lack of structures and facilities to ease procurement process and pervading corruption in Nigeria have hindered the full implementation of the Act.  Furthermore, the study concludes that the implementation of the public procurement Act is a catalyst to transparency, accountability, efficiency, and value for money. Subsequently, the study recommends that there should be strong commitment and political will to implement the public procurement Act in all levels of government. This will metamorphose to transparency, competitiveness, accountability, and fairness in the award of government contracts.
Materials Management and its Effect on the Performance of Manufacturing Sector: Evidence from Nigerian Cement Industry
Authors: Florence F. Oyebamiji,
Published: March 2019

The study examined the effect of materials management on the performance of manufacturing industry with particular reference to the selected cement industry. Purposive sampling technique was employed to select Dangote Cement Plc, Ashaka Cem Plc and Lafarge Africa Plc, while judgmental technique was used to select ten (10) staff members from purchasing/store/ logistic department of the selected cement industry respectively, totalling thirty (30) respondents as a sample size for the study. The data collection instrument for the study was a structured questionnaire and a personal interview. Data analysis was conducted with the aid of multiple regression analysis. Result revealed that materials management dimensions jointly contribute significantly to firm performance.  The study further revealed that materials inventory, materials procurement and inter-departmental collaboration have an insignificant effect on firm performance, while only materials storage has a significant impact on firm performance.  The study concluded that effective materials management is a veritable tool to organization performance. Subsequently, the study recommended that management should embrace effective materials management especially in the area of materials inventory, materials procurement and inter-departmental collaboration, in order for the industry to achieve its vision of being a global leader in cement production and the largest employers of labour in the world by 2030.
Hazardous Working Conditions and Employers Perception Regarding Child Laborer: A Study at Sylhet City of Bangladesh
Authors: Ahad Md. Abdul , Eleen Farjana , Chowdhury Mitu
Published: March 2019

In Bangladesh, children are working under hazardous condition due to the necessity that pushes them to labour. The present study is an attempt to explore the socio-economic conditions of child labourers, working conditions as well as employer’s views regarding child labours of Sylhet city. The study was conducted through personal interview with 70 child labourers and 50 employers. The simple random sampling procedure was used to select respondents. The study reveals that 48% cannot read and write. In case of occupation, 20% are automobile worker, 18% are rickshaw puller and 13% are domestic labor. About 64% of child labourers are landless, and 40% of the child labourer's monthly income rages from 600-1000 Taka as well as 40% are dependent on employer’s convenience. About 45% child labourer's working in hazardous environment and 76% are working 11 or more hours per day. Safeguard and medical facilities from owner’s side are not satisfactory. According to employers view, 32% and 28% recruit child labourers because of their obedience and availability of child workers respectively. Most of the employer’s (46%) recruit child labourer through the help of worker’s parents/relatives. Almost all of the employers revealed that they do not provide medical, transportation, even training facilities to the child labourers. But 84% of the employers provide foods during work time. The above data are clearly reflecting the hazardous circumstances of child labourers. Finally, areas and context-specific data are essential to raise awareness against child labour and also for future policies and effective surveillance initiatives.
The Effectiveness of Switching Barrier on Customer Loyalty Mediated with Customer Satisfaction: Telecommunication Industry, Batticaloa
Authors: Howshigan Shamini , Ragel V. R.
Published: March 2019

The mobile telecommunications service providers face technical hitches to meet customer loyalty, to increase the market share. Therefore, service providers should be conscious of the factors affecting customer loyalty in building strong relationships. This study aims to investigate the effectiveness of switching barrier on customer loyalty with regards to customer satisfaction in mobile telecommunication service providers. The objective of this study is to identify the level, relationship and impact of switching barrier on customer satisfaction and loyalty. Finally, the study examines the mediating role of satisfaction. This study was based on the customer’s perspectives and their experiences with mobile telecommunications service in Batticaloa. Data were obtained from the sample 200 customers, and stratified random sampling was used. The descriptive statistics, correlation and regression analysis were used to analyse the data.

The results revealed that the switching barrier has a significant impact on loyalty and satisfaction. Same as satisfaction has significant impact on loyalty. And also, switching barrier impact on customer loyalty significantly through customer satisfaction. The study contributes to existing theoretical and practical knowledge by providing evidence regarding the relationships between switching barrier on customer loyalty, and customer satisfaction. The telecommunication service providers, in Sri Lanka; it is growing rapidly with high competition between the service providers. Hence, this research has the potential to contribute to the overall telecommunication service providers in terms of how to maintain long-term relationships between the service providers and their customers through the strategies of switching barrier.
Exploring the Relationship between Strategic Outsourcing and Organisational Performance: A Study of Nigerian Insurance Companies
Authors: Sola Kareem, Thompson , Unachukwu J. C. , Abiodun Okegbemi, Festus
Published: March 2019

This study examines the relationship between strategic outsourcing and the performance of insurance companies in Nigeria with specific reference to the selected insurance companies. Purposive sampling technique was used to select top 10 best ranking insurance companies in Nigeria and five (5) staff members were select from each 10 insurance company, totaling 50 respondents as a sample size for the study.  A structured closed ended questionnaire designed for the study was used to collect the data from the respondents. Data analysis was performed with the aid of frequencies, percentages and correlation analysis.  Result reveals that strategic outsourcing has significant relationship with the performance of insurance companies in Nigeria.  The finding also establishes that core functions are largely arranged internally while security services, advertising and marketing, recruitment services and catering services functions are fully outsourced by most companies in Nigeria. Finding also reveals that company's attachment to its brand and processes; inability to develop clear objectives; inadequate supporting infrastructure; absence of performance measures and lack of top management support are the major challenges confronting the implementation of strategic outsourcing in most of the insurance companies in Nigeria. Subsequently, the study recommends that management should give maximum support for the implementation of the strategic outsourcing and enlightenment programme on the benefits of strategic outsourcing should be organised for all stakeholders to reduce the chances of resistance.
Analysis of Socio-economic Factors and Profitability of Hybrid Maize Production in Eastern Terai of Nepal
Authors: Adhikari Surya Prasad , Shrestha Keshav Prasad , Shrestha Shukra Raj
Published: March 2019

The study was conducted to analyze the socioeconomic factors and profitability of hybrid maize production in eastern Nepal. A household survey was conducted from March to April, 2017 in two districts Morang and Sunsari to collect information on socioeconomic characteristics and economics of maize production. The Structured questionnaire was administered to 98 randomly selected households from two districts i.e. 41 from Morang and 57 from Sunsari district. Descriptive and statistical tools including multiple regression model were used to analyze the data. The multiple regression model showed that larger the maize area, higher the education of household head and households who received maize farming related training were significant and positive towards maize output. Farmers of Morang district have higher maize production than Sunsari district. The benefit-cost ratio (1.7) indicates that hybrid maize farming was profitable with productivity of 6.9 ton per hectare. Despite the importance of maize crop to household income, many constraints were reported in its productivity including lack of irrigation, a high cost of inputs and the incidence of pests and diseases. Ensuring access to irrigation, training on maize farming, mechanization and efficient extension services were recommended to increase hybrid maize production in eastern Nepal.
Poverty Menace and Social Economic Nexus in Nigeria: A Bound Test Approach
Authors: Emife Nwani, Stanley , Elvis Ozegbe, Azuka , Nwabuisi Onochie, Stanley
Published: March 2019

Nigeria has recorded variations in major macroeconomic variables since independence. Growth episodes over the years though encouraging put has not translated to improvement in poverty incidence. The rate of poverty in the nation has out-grown population growth, hence, this study seeks to relate various sectors of the economy to the perturbing poverty level in the nation with emphasis on the social sectors in which health and education play integral roles. This study examines poverty and social economic mix in Nigeria with the objectives of ascertaining the partial impacts of productivity (as a measure of health outcome), public social expenditures, agricultural output, manufacturing output and infrastructural development on poverty incidence, the study collected secondary annual time series data spanning 37 years from 1981 to 2017 on poverty index (PVTI), productivity due to good health (HP) and other explanatory variables as earlier identified. The pre-estimation techniques adopted include descriptive statistics, Phillips-Perron stationarity test and bounds test to co-integration. The preliminary result reveals that the variables in the model have long run relationship. The parameters of the model were estimated using the ARDL technique and the study found that productivity due to good health (HP) has significant effect on poverty reduction, as public social expenditures, current period’s agricultural output and previous period manufacturing output have similar effects but not statistically significant, however, infrastructural development and current manufacturing output have significant positive impact on poverty incidence in the country. On the basis of our empirical revelation, the study recommends that government should adopt multi-sectoral and big push development approaches with priority on employees’ productivity through free health care programmes for the unemployed, quality health insurance scheme for the employed, free education for children of the poor and unemployed, and that investment in critical infrastructures such as roads, rail, energy and storage facilities that promote agriculture and manufacturing outputs be improved upon if poverty is to be decisively tackled in Nigeria.
Human Resources Management in Government: Case study of Vietnam
Authors: Hai Do Phu
Published: March 2019

This article is represented for a case study about human resources management in government of Vietnam. The research objective is to assess the existing system of human resources management in government of Vietnam and find out the direction of human resources management in government. The research demonstrated a moving from the existing system to the professional system from internal weaknesses and external challenges of the human resources management in Government of Vietnam. A combination of career based system and position based system is the right strategy for Vietnam as well as developing countries. Key elements of position based system and new public management should be adopted with a best practice of competency based human resources management framework which is very productive for Vietnam and developing countries.
Redistribution Activities of Distributors in the Brewing Industry in an Emerging Economy
Authors: Adusei Charles , Tweneboah-Koduah Isaac
Published: March 2019

The decision about marketing channels selection is critical as it ultimately affects the other supply chain activities of any business. The purpose of this study was to examine the redistribution role of distributors in the brewing industry. The study employed a survey using a single case study from the perspective of retail outlets. The study revealed that availability and visibility of brands increased brand penetration coupled with effective coverage and management of sales territories by the distributor. The outlets indicated that getting all the empties for their purchase of products was a challenge. The study suggests that distributors must be accountable and ensures flawless sales force coverage and effectiveness to avoid out-of-stocks situations. Manufacturers must intensify their trade and consumer promotions concurrently to really connect the push and pull aspect of distribution.
Molecular discrimination and phylogeographic patterns of clones of the parthenogenetic gecko Lepidodactylus lugubris in the Japanese Archipelago
Authors: Murakami Yuki , Hayashi Fumio
Published: March 2019

Vertebrates usually reproduce sexually in which males and females contribute their offspring genome and produce genetically diverse offspring. However, some of them are asexual without genetic contribution from males. The nocturnal gecko, Lepidodactylus lugubris, is all females and reproduces parthenogenetically. This gecko is known to consist of diploid and triploid clones in the tropical and subtropical regions, which can be identified by their dorsal marking patterns, ploidy, and protein polymorphism. This gecko is also distributed in the southern parts of Japan, and several clones have been reported. In this study, we investigated the origins and genetic diversity of Japanese L. lugubris by clonal discrimination using microsatellite and mitochondrial DNA analyses. A total of 748 individuals were collected from 21 islands of five island groups (Ogasawara, Okinawa, Miyako, Yaeyama and Daito Islands) and 17 clones were distinguished genetically. Mitochondrial cyt b sequences of these clones suggested that they were all closely related and differentiated recently. Clonal diversity was much higher (14 clones) in the Daito Islands than in the other island groups in which only one or two clones coexisted. Judging from the dorsal marking patterns and ploidy known so far, six clones were cosmopolitan and may be colonized from the outside of Japan. However, other 11 clones were endemic to the Daito Islands and explained by possible hybridization between the one female diploid clone and one male diploid clone because other 9 clones were triploid and all had the combinations of polymorphic microsatellite alleles of these female and male diploid clones. Although the males have never been recorded in the Daito Islands, males might appear in the past. These findings contribute to understanding of clonal diversity and dynamics of asexually reproducing animals. If diploid parthenogenetic geckos can produce triploid clones by mating with the diploid males, clonal diversity would increase rapidly in a small island, and such newly produced triploid clones would expand widely.
AaPP2C1 negatively regulates the expression of genes involved in artemisinin biosynthesis through dephosphorylating AaAPK1
Authors: Zhang Taixin , Gou Yuqin , Bai Feng , Bai Ge , Chen Min , Zhang Fangyuan , Liao Zhihua
Published: March 2019

Artemisinin is biosynthesized in Artemisia annua and widely used for the treatment of malaria. Abscisic acid (ABA)‐responsive kinase 1 (AaAPK1), a member of the SnRK2 family, is involved in the regulation of artemisinin biosynthesis through the phosphorylation of AabZIP1, which directly transactivates genes involved in artemisinin biosynthesis. Through diverse assays – including yeast two‐hybrid and bimolecular fluorescence complementation assays – we report that the ABA‐responsive protein phosphatase AaPP2C1 physically interacts with AaAPK1. In addition, phos‐tag mobility shift assays indicate that AaPP2C1 dephosphorylates AaAPK1. Moreover, dual‐luciferase assays demonstrate that the presence of AaPP2C1 reduces the transactivation of artemisinin biosynthesis genes by AabZIP1. These results further refine the post‐translational regulatory network of artemisinin biosynthesis, showing that AaPP2C1 is negatively involved through dephosphorylation of AaAPK1.
Impact of Patient's Global Assessment on Achieving Remission in Patients With Rheumatoid Arthritis: A Multinational Study Using the METEOR Database
Authors: Ferreira Ricardo J. O. , Carvalho Pedro David , Ndosi Mwidimi , Duarte Cátia , Chopra Arvind , Murphy Elizabeth , van der Heijde Désirée , Machado Pedro M. , da Silva José A. P.
Published: March 2019

Objective

There is an ongoing debate about excluding patient's global assessment (PtGA) from composite and Boolean‐based definitions of rheumatoid arthritis (RA) remission. This study aimed at determining the influence of PtGA on RA disease states, exploring differences across countries, and understanding the association between PtGA, measures of disease impact (symptoms), and markers of disease activity (inflammation).

Methods

Cross‐sectional data from the Measurement of Efficacy of Treatment in the Era of Outcome in Rheumatology international database were used. We calculated the proportion of patients failing American College of Rheumatology/European League Against Rheumatism Boolean‐based remission (4‐variable remission) solely due to PtGA (PtGA‐near‐remission) in the overall sample and in the most representative countries (i.e., those with >3,000 patients in the database). Multivariable linear regression models were used to identify the main determinants of PtGA, grouped in predominantly inflammatory impact factors (28 tender joint counts, 28 swollen joint counts, and C‐reactive protein level) and disease impact factors (pain and function).

Results

This study included 27,768 patients. Excluding PtGA from the Boolean‐based definition (3‐variable remission) increased the remission rate from 5.8% to 15.8%. The rate of PtGA‐near‐remission varied considerably between countries, from 1.7% in India to 17.9% in Portugal. One‐third of the patients in PtGA‐near‐remission group scored PtGA >4 of 10. Pain and function were the main correlates of PtGA, with inflammation‐related variables contributing less to the model (R2 = 0.57).

Conclusion

PtGA is moderately related to joint inflammation overall, but only weakly so in low levels of disease activity. A considerable proportion of patients otherwise in biologic remission still perceive high PtGA, putting them at risk of excessive immunosuppressive treatment.
Magazine‐Bending‐Inspired Architecting Anti‐T of MXene Flakes with Vertical Ion Transport for High‐Performance Supercapacitors
Authors: Lu Ming , Han Wenjuan , Li Haojie , Li Haibo , Zhang Bingsen , Zhang Wei , Zheng Weitao
Published: March 2019

MXenes have shown distinctive advantages as active materials for supercapacitors due to their 2D open structure and high electronic conductivity. However, the horizontal stack and random orientation of MXene flakes on a current collector lead to the limited accessible surface area and transport pathways. Blocking the ion transport is largely deteriorated for the electrochemical performance of an MXene electrode. Herein, a vacuum filtration process, affording with the entwined mental mesh as filter membranes, is employed for constructing an “anti‐T‐shape” MXene film electrode. The resultant vertical ionic tunnels improve the kinetics of electrolyte ion transport. Consequently, a lower interfacial charge transfer impedance and an increased pseudo‐capacity are achieved in the sulfuric acid electrolyte. This work may inspire further investigations on anisotropic properties of MXenes beyond electrochemical energy storage.
Ultrasmall Optical Vortex Knots Generated by Spin‐Selective Metasurface Holograms
Authors: Wang Lei , Zhang Weixuan , Yin Hongxing , Zhang Xiangdong
Published: March 2019

Tying isolated vortex knots in complex optical fields has been recently realized using spatial light modulators (SLMs). These traditional devices suffer from low efficiency, narrow bandwidth, and they cannot be integrated to nanophotonic systems. Here, the design and realization of metasurface holograms (MHs) is reported to efficiently generate the optical vortex knots in a broad spectral region. In comparison with conventional optical devices, the thicknesses and pixels of MHs are both in subwavelength scale, and the size of created optical vortex knot can be six orders of magnitude smaller than those produced by SLMs. Such extremely little vortex knots may find widespread applications in templating knotted micro/nano‐structures in photosensitive materials and 3D optical trapping of cold atoms in complex topologies at microscale. In particular, it is found that the spatial position of the generated off‐axis optical vortex knot is able to be symmetrically reversed by just changing the helicity of the incident light. This spin‐selective vortex knot generator can be regarded as a new type of metasurface device for manipulating the topological structure of optical vortex lines, which has potential applications in the field of singular optics.
The City and Extreme Weather: How Cities Should Respond to Climate Change
Authors: Kaltenbrunner Robert
Published: March 2019

The following essay focuses on the impacts of climate toward cities—and on the inherent restraints, which one has to deal with. There is today a necessity of strategies for urban resilience. These move away from the idea that space must be used in the most efficient way possible: instead, tolerances will be built in, buffers formed, which should lead at the same time to added spatially quantitative value. It is as right as it is necessary to develop a vision of climate‐friendly and CO2‐neutral cities and regions. On the one hand, one must ask how all of the uncertainties can be handled in the planning. On the other hand, one must engage oneself to anchor—more precisely, to better anchor—integrated climate protection and adaptation strategies to everyday activities: not only for regional planning or urban development, but also among private builders and property owners.
2D Single‐Layer π‐Conjugated Nickel Bis(dithiolene) Complex: A Good‐Electron‐Poor‐Phonon Thermoelectric Material
Authors: Deng Tianqi , Yong Xue , Shi Wen , Gan Chee Kwan , Li Wu , Hippalgaonkar Kedar , Zheng Jin‐Cheng , Wang Xiaobai , Yang Shuo‐Wang , Wang Jian‐Sheng , Wu Gang
Published: March 2019

Recently, the 2D d8 planar π‐conjugated transition metal complexes have gained extensive attention owing to their extra‐high electrical conductivity. Meanwhile, low lattice thermal conductivities can be expected for their soft and microporous structures, suggesting very promising thermoelectric applications. Herein, based on first‐principles calculations and molecular dynamics simulations, it is identified that monolayered 2D nickel bis(dithiolene) complex, (NiC4S4)n, is indeed such a material that exhibits exceptionally high electron mobility, low lattice thermal conductivity, and thereby excellent thermoelectric performance. The calculated figure of merit at 300 K can reach up to 0.92 for a perfect nanosheet. At the same time, the mechanism behind is uncovered, that is, the weak electron‐acoustic‐phonon coupling allowing high electron mobility, and its microporous structure decreasing the thermal transport. The surprisingly weak electron‐acoustic‐phonon coupling arises from mixed bonding–antibonding nature of conduction band. The finding opens a new opportunity for these 2D coordination complexes as potential thermoelectric materials.
High‐Performance Electrocatalytic Conversion of N2 to NH3 Using Oxygen‐Vacancy‐Rich TiO2 In Situ Grown on Ti3C2Tx MXene
Authors: Fang Yanfeng , Liu Zaichun , Han Jingrui , Jin Zhaoyong , Han Yaqian , Wang Faxing , Niu Yusheng , Wu Yuping , Xu Yuanhong
Published: March 2019

To achieve the energy‐effective ammonia (NH3) production via the ambient‐condition electrochemical N2 reduction reaction (NRR), it is vital to ingeniously design an efficient electrocatalyst assembling the features of abundant surface deficiency, good dispersibility, high conductivity, and large surface specific area (SSA) via a simple way. Inspired by the fact that the MXene contains thermodynamically metastable marginal transition metal atoms, the oxygen‐vacancy‐rich TiO2 nanoparticles (NPs) in situ grown on the Ti3C2Tx nanosheets (TiO2/Ti3C2Tx) are prepared via a one‐step ethanol‐thermal treatment of the Ti3C2Tx MXene. The oxygen vacancies act as the main active sites for the NH3 synthesis. The highly conductive interior untreated Ti3C2Tx nanosheets could not only facilitate the electron transport but also avoid the self‐aggregation of the TiO2 NPs. Meanwhile, the TiO2 NPs generation could enhance the SSA of the Ti3C2Tx in return. Accordingly, the as‐prepared electrocatalyst exhibits an NH3 yield of 32.17 µg h−1 mg−1cat. at −0.55 V versus reversible hydrogen electrode (RHE) and a remarkable Faradaic efficiency of 16.07% at −0.45 V versus RHE in 0.1 m HCl, placing it as one of the most promising NRR electrocatalysts. Moreover, the density functional theory calculations confirm the lowest NRR energy barrier (0.40 eV) of TiO2 (101)/Ti3C2Tx compared with Ti3C2Tx or TiO2 (101) alone.
Evaluating elbow osteoarthritis within the prehistoric Tiwanaku state using generalized estimating equations (GEE)
Authors: Becker Sara K.
Published: March 2019

Objectives

Studies of osteoarthritis (OA) in human skeletal remains can come with scalar problems. If OA measurement is noted as present or absent in one joint, like the elbow, results may not identify specific articular pathology data and the sample size may be insufficient to address research questions. If calculated on a per data point basis (i.e., each articular surface within a joint), results may prove too data heavy to comprehensively understand arthritic changes, or one individual with multiple positive scores may skew results and violate the data independence required for statistical tests. The objective of this article is to show that the statistical methodology Generalized Estimating Equations (GEE) can solve scalar issues in bioarchaeological studies.

Materials and methods

Using GEE, a population‐averaged statistical model, 1,195 adults from the core and one colony of the prehistoric Tiwanaku state (AD 500–1,100) were evaluated bilaterally for OA on the seven articular surfaces of the elbow joint.

Results

GEE linked the articular surfaces within each individual specimen, permitting the largest possible unbiased dataset, and showed significant differences between core and colony Tiwanaku peoples in the overall elbow joint, while also pinpointing specific articular surfaces with OA. Data groupings by sex and age at death also demonstrated significant variation. A pattern of elbow rotation noted for core Tiwanaku people may indicate a specific pattern of movement.

Discussion

GEE is effective and should be encouraged in bioarchaeological studies as a way to address scalar issues and to retain all pathology information.
Carotid foramen size in the human skull tracks developmental changes in cerebral blood flow and brain metabolism
Authors: Harrington Arianna R. , Kuzawa Christopher W. , Boyer Doug M.
Published: March 2019

Objectives

In humans, neuronal processes related to brain development elevate the metabolic rate of brain tissue relative to the body during early childhood. This phenomenon has been hypothesized to contribute to slow somatic growth in preadolescent Homo sapiens. The uncoupling of the brain's metabolic rate from brain size during development complicates the study of the evolutionary emergence of these traits in the fossil record. Here, we extend a method previously developed to predict interspecific differences in cerebral blood flow (a correlate of cerebral glucose use) to predict ontogenetic changes in human brain metabolism.

Materials and methods

Radii of the carotid foramen from an ontogenetic series of modern human crania were used to predict blood flow rates through the internal carotid arteries (ICA), which were compared to empirically measured ICA flow and brain metabolism values.

Results

Predictions of both absolute ICA blood flow rates and perfusion (ICA blood flow rates relative to brain size) generally match measured values in infancy and childhood. Maximum predicted ICA blood flow rates and perfusion were found to occur between ages 5 and 8, which roughly correspond to the age of maximum measured ICA blood flow rate and absolute and brain mass‐specific rate of whole brain glucose uptake.

Discussion

These findings suggest that, during human growth and development, the size of the carotid foramen corresponds well to blood flow requirements through the ICA, and the method tested here may provide new opportunities for studying developmental changes in brain metabolism using osteological samples, including fossil hominins.
Self‐Assembly through Coordination and π‐Stacking: Controlled Switching of Circularly Polarized Luminescence
Authors: Niu Dian , Jiang Yuqian , Ji Lukang , Ouyang Guanghui , Liu Minghua
Published: March 2019

Multiple noncovalent interactions can drive self‐assembly through different pathways. Here, by coordination‐assisted changes in π‐stacking modes between chromophores in pyrene‐conjugated histidine (PyHis), a self‐assembly system with reversible and inversed switching of supramolecular chirality, as well as circularly polarized luminescence (CPL) is described. It was found that l‐PyHis self‐assembled into nanofibers showing P‐chirality and right‐handed CPL. Upon ZnII coordination, the nanofibers changed into nanospheres with M‐chirality, as well as left‐handed CPL. The process is reversible and the M‐chirality can change to P‐chirality by removing the ZnII ions. Experimental and theoretical models unequivocally revealed that the cooperation of metal coordination and π‐stacking modes are responsible the reversible switching of supramolecular chirality. This work not only provides insight into how multiple noncovalent interactions regulate self‐assembly pathways.
Synthesis of Urea Derivatives from CO2 and Silylamines
Authors: Xu Maotong , Jupp Andrew R. , Ong Maegan S. E. , Burton Katherine I. , Chitnis Saurabh S. , Stephan Douglas W.
Published: March 2019

A series of thirty‐three N,N′‐diaryl, dialkyl, and alkyl‐aryl ureas have been prepared in pyridine or toluene by reaction of silylamines with CO2. This protocol is shown to provide facile access to 13C‐labeled ureas, as well as chiral and macrocyclic ureas. These reactions proceed through initial generation of the corresponding silylcarbamates, which subsequently react with silylamine under thermal conditions to afford the thermodynamically favored urea and disilyl ether.
Chemical Vapor Deposition of Phase‐Pure Uranium Dioxide Thin Films from Uranium(IV) Amidate Precursors
Authors: Straub Mark D. , Leduc Jennifer , Frank Michael , Raauf Aida , Lohrey Trevor D. , Minasian Stefan G. , Mathur Sanjay , Arnold John
Published: March 2019

Homoleptic uranium(IV) amidate complexes have been synthesized and applied as single‐source molecular precursors for the chemical vapor deposition of UO2 thin films. These precursors decompose by alkene elimination to give highly crystalline phase‐pure UO2 films with an unusual branched heterostructure.
Fire retardance and smoke suppression of polypropylene with a macromolecular intumescent flame retardant containing caged bicyclic phosphate and piperazine
Authors: Yang Rong , Ma Binbin , Zhang Xin , Li Jinchun
Published: March 2019

A macromolecular intumescent flame retardant (FR) named PPPAP was designed and synthesized with phosphorus chloride (the acid source), 2,6,7‐trioxa‐l‐phosphabicyclo[2.2.2]‐octane‐4‐methanol (the charring agent), and anhydrous piperazine (the blowing agent). Then, it was used to prepare an intumescent flame‐retardant polypropylene (FR‐PP). The thermal stability, flame retardancy, and fire performance of the FR‐PPs were investigated. The results show that the initial decomposition temperature and char residue at 700 °C of PPPAP were 260.8 °C and 31.8%, respectively. The limiting oxygen index (LOI) value of polypropylene (PP) was enhanced with increasing PPPAP content. With the addition of 40 wt % PPPAP, the LOI value of FR‐PP was 29%, and it passed the vertical burning UL‐94 V‐0 rating. The cone calorimetry results indicate that not only the peak heat‐release rate but also the total smoke production of PP significantly decreased to 65.7 and 79.5%, respectively, with the incorporation of only 20 wt % PPPAP. The FR mechanism suggested that PPPAP played a part in both the gas and condensed phases, and the formation of the intumescent char layer during combustion was the dominant FR mechanism. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47593.
Feasibility of unsaturated fatty acid feedstocks as green alternatives in bio‐oil refinery
Authors: Jeon Jong Yeol , Han Yohan , Kim Young‐Wun , Lee Youn‐Woo , Hong Sukwon , Hwang In Taek
Published: March 2019

Bio‐oil contains plant, animal, fish, and micro‐algae oil, and more than 200 million tons are produced annually. However, many edible and non‐edible bio‐oils are still under development, and their value and feasibility have yet to be determined. The vast majority of bio‐oils produced in the world have a very high unsaturated fatty acid content (70–98%), which could be used as a renewable, eco‐friendly alternative to petroleum. Hydrolysis (or transesterification) with ethylene metathesis technology converts unsaturated fatty acids to C4–C30 oil fragments. These oil fragments are a sustainable chemical technology used in chemical industry platform technology and carbon dioxide abatement green chemical technology, and as a petrochemical substitute. These platform chemicals also have their own market but are used as raw materials for other products (polymers, surfactants, synthetic lubricants, plasticizers, other specialty chemicals, general purpose chemicals, biofuels, etc.). The biodegradability and biocompatibility of the polymeric materials made from the oil mean that it is also possible to develop diverse functional products with high added value such as toothpaste, dandruff treatment shampoo, and melanin pigment removal cosmetics, medical and shape memory polymer materials. According to the cradle‐to‐gate analysis for environmental impact and economics, the total carbon dioxide emission reduction per ton of soybean oil was estimated to be 1.5 kg kg−1 products. Moreover, the metathesis of soybean oil ($680/ton) with additional raw materials ($237.4) will generate a value that is 7.5 times higher at $6857. Due to the biodegradability and biocompatibility of the products made from bio‐oils, it is expected that various functional products with high added value will be developed and that industrial applicability will be greatly expanded in the near future. In addition, for the development of various derivatives, fusion and cooperative research in chemical fields such as catalytic engineering, organic chemistry, polymer chemistry, maintenance chemistry, and reaction engineering are essential. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd
Neuropeptidomics: Comparison of parallel reaction monitoring and data‐independent acquisition for the analysis of neuropeptides using high‐resolution mass spectrometry
Authors: Saidi Mouna , Kamali Soufiane , Beaudry Francis
Published: March 2019

Targeted peptide quantitation by mass spectrometry is a rapidly emerging field. Traditionally it relied on the development and validation of multiple reaction monitoring assays that could comply with a high level of sensitivity, specificity, accuracy and reproducibility in complex biological samples. However, with the introduction of high‐resolution mass spectrometers, other acquisition modes could provide more comprehensive datasets for identification and quantification but also for in‐depth data mining. The objective of this study was to evaluate two analytical approaches, parallel‐reaction monitoring (PRM) and data‐independent analysis (DIA) using a hybrid Quadrupole–Orbitrap mass spectrometer for the quantification of neuropeptides in animal spinal cord tissues. Mouse spinal cord tissues were harvested, homogenized and neuropeptides extracted using a C18 solid‐phase extraction protocol. Chromatography was achieved using a Thermo Biobasic C8 100 × 1 mm (5 μm) column. The initial mobile phase conditions consisted of acetonitrile and water (both containing 0.1% of formic acid) at a ratio of 5:95. An 11 min linear gradient was applied up to a ratio of 50:50 and maintained for 3 min. The flow rate was fixed at 75 μL/min and 2 μL of sample was injected. Mass spectrometry analyses were performed using a Thermo Q Exactive Plus MS using PRM and DIA approaches. Quantitative data using an isotopic dilution and a label‐free strategy were obtained for both methods and statistically compared. Using both approaches, we were able to clearly detect endogenous neuropeptides. However, with DIA, mass spectra alone could not distinguish Leu‐Enk and Met‐Enk. We used a Bland–Altman plot (Difference plot) to analyze the agreement between both approaches and no systematic bias was observed. Further statistical analyses, including variance analysis, showed more variability in DIA compared with PRM mode. Further analyses were performed using a label‐free approach and confirmed an increase of the variance using a DIA approach.
Muscle power, contraction velocity and functional performance after stroke
Authors: Kostka Joanna , Niwald Marta , Guligowska Agnieszka , Kostka Tomasz , Miller Elżbieta
Published: March 2019

Objective

The goal of this study was to describe muscle function deficit in patients after stroke as well as to define the relationship between maximal muscle power (Pmax) and optimal shortening velocity (υopt) with functional efficiency in stroke survivors.

Material and Methods

A total of 134 participants were enrolled in the study, including 67 patients after a stroke and 67 volunteers, matched for age and sex (controls). Functional performance was measured with the timed Up and Go test (TUG) and additionally with Rivermead Motor Assessment (RMA) and Barthel Index (BI) in stroke survivors. To assess Pmax and υopt of the knee extensor muscles, a specially equipped Monark cycle ergometer was used.

Results

The power generated by stroke survivors was 49.6% that of their peers and muscle contraction velocity was 65.5%. Pmax/kg and υopt were associated with TUG outcomes in both groups. Pmax/kg and υopt were associated with age in the control group, but not in patients after stroke. In multivariate analysis in patients after stroke, TUG was better predicted by Pmax/kg or υopt than by the age. In stroke survivors, both Pmax/kg and υopt were related to the BI and to the RMA total results. Both BI and RMA total were not determined by age.

Conclusions

Muscle power and muscle contraction velocity in patients who have had a stroke within three months have reduced markedly. These factors significantly affect functional performance. Muscle power and optimal shortening velocity are more important determinants of functional status than age in these stroke survivors.
A hidden rib found in Michelangelo Buonarroti's fresco The Creation of Adam
Authors: de Campos Deivis
Published: March 2019

The fresco The Creation of Adam (1511), painted on the ceiling of the Sistine Chapel by the great genius of human anatomy Michelangelo Buonarroti (1475–1564), represents one of the most emblematic and best‐known scenes in the world. This fresco illustrates a key passage from the Book of Genesis: the moment when God creates the first man, Adam. Since its completion, this work has been intensively studied by many scholars of art, and by several anatomists, who have pointed out signs of anatomical representations contained in the scene. However, there is still some uncertainty regarding this famous scene, especially in relation to its complete iconography. In an attempt to understand Michelangelo's purpose better regarding this emblematic scene, this article presents unpublished evidence that the artist could have concealed within the figure of Adam the anatomical image of a rib which, according to traditional Biblical accounts, is iconographically associated with the origin of Eve, Adam's companion. Curiously, this hidden rib in Adam's body figure could be related to the traditional view of the origin of the first humans expounded in the Jewish Kabbalah. Clin. Anat. 32:648–653, 2019. © 2019 Wiley Periodicals, Inc.
Teaching combustion thermochemistry with an interactive Matlab application
Authors: García‐Oliver José María , García Antonio , de la Morena Joaquín , Monsalve‐Serrano Javier
Published: March 2019

Computer‐aided‐learning has been found to improve notably the learning efficiency as compared with classical teaching. In this study, an interactive Matlab application has been developed to be used when teaching combustion thermochemistry in engineering degrees. The use of this tool in practical sessions allows the students to concentrate on understanding the links between the boundary conditions of a combustion process and the corresponding outputs in terms of species composition and temperature. Moreover, the students can check the differences between the results obtained from a complex calculation (with the interactive tool) and those obtained by means of the simplified calculations performed during the theoretical lessons and written exams. The analysis of the outcomes after several years using this tool revealed that the students are generally satisfied with the practical session, and the analysis of the marks confirms the robustness of the methodology proposed.
Narcissistic Leadership: When Serving Self Eclipses Serving Mission
Authors: Hellmich David , Hellmich Linda
Published: March 2019

This chapter distinguishes narcissism from healthy self‐esteem, describes ethical dilemmas institutions may face when decision‐making is controlled by narcissistic leaders, and recommends safeguards against narcissistic leadership.
Boron−Boron Dehydrocoupling of Boranes Initiated by Reaction with Iodine
Authors: Elias Jana , Kaifer Elisabeth , Himmel Hans‐Jörg
Published: March 2019

A new boron–boron dehydrocoupling strategy was established, providing convenient access to some diborane(4) compounds starting from simple borane adducts under mild conditions. In contrast to the traditional pathway using a reducing reagent, the reduction from BIII to BII was paradoxically initiated by the addition of the oxidation‐reagent iodine. A reaction pathway for this unusual reaction was proposed based on quantum‐chemical calculations.
Analysis of Membrane Reactors for Integrated Coupling of Oxidative and Thermal Dehydrogenation of Propane
Authors: Brune Andreas , Wolff Tanya , Seidel‐Morgenstern Andreas , Hamel Christof
Published: March 2019

This study presents strategies capable to intensify the thermal dehydrogenation of propane (TDH) using integrated reactor concepts. An inert packed bed membrane reactor for distributed dosing of oxygen to realize the oxidative dehydrogenation (ODH) was studied and compared to a reactor with catalytically active membrane. The latter concept allows to combine TDH and ODH in one apparatus to overcome the chemical equilibrium by in situ conversion of the by‐product H2using O2or in a reverse water‐gas shift reaction by CO2. If CO2is used as active sweep gas the reactor offered better performance regarding yield and selectivity. Strategies for further thermal integration are discussed.
Shear rheological properties of composite fluids and stability of particle suspensions: Potential implications for fracturing and environmental fluids
Authors: Pensini Erica , Rodriguez Braulio Macias , Marangoni Alejandro G. , Collier Christopher M. , Elsayed Abdallah , Siwik Amanda
Published: March 2019

Composite fluids are comprised of particles and polymers and are used for fracking and the in‐situ treatment of subsurface contaminants. This study investigates the correlation between the shear viscoelasticity of guar aqueous solutions and their effectiveness in suspending sand, which is a common fracking proppant. In the absence of a crosslinker, the shear viscous modulus (G”) of 5 g/L guar solutions was greater than the shear elastic modulus (G’). When the crosslinker borax was added, the guar solutions behaved as yield stress fluids (G’ > G”). Sand was well‐suspended in the crosslinked guar solutions but settled in non‐crosslinked fluids. Similar results were obtained with fenugreek gum. This study also investigates the correlation between particle settling and the effect of particle addition on the rheology of the fluids. Granulated activated carbon (GAC) particles are utilized to remediate polluted sites and were used as model particles. Guar and xanthan effectively suspended the GAC. Anionic polyacrylamide effectively suspended the GAC but not after soaking in sodium dodecyl sulphate. Zetag 8167 did not effectively suspend the GAC. The addition of 10 g/L of GAC did not affect the shear rheology of the fluids that suspended them, but decreased the shear viscoelastic moduli of the polymeric fluids that could not suspend them.