bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and Theoretical Evaluation of the Structure and Properties of New Stannyl Complexes of Pyridine Amide Ligands
Authors: Thomas Raji , Pardasani Pushpa 
Published: July 2019

Aims: Penta and tetra coordinated stannyl derivatives of N, N'-Bis(2-pyridyl)pyridine-2,6-dicarboxamide (H2L) and N-(pyridine-2-yl)picolinamide (HL1) have been synthesized. The structure of the complexes has been well established by Sn119 NMR and computational studies (GAUSSIAN 03 suit of programs). MESP and NBO studies have been carried out to understand different binding modes and properties of the complexes as well as ligands. The relative bond strengths have been estimated using the Wiberg bond index analysis.
Study Design: Experimental and computational.
Place and Duration of Study: Department of Chemistry, University of Rajasthan, Jaipur, 2014.
Methodology: The structure of the complexes has been analyzed by IR and NMR. Computational studies (GAUSSIAN 03 suit of programs) have been used to elucidate the structure of the newly synthesized complexes.
Results: 119Sn NMR showed a pentacoordinate range for diamide complexes indicating coordination through the nitrogen of central pyridine ring in addition to amide nitrogens and tetracoordinate range for monoamide complexes confirming the formation of the products. The bonding properties have been confirmed by the computational calculations.
Conclusion: A series of dialkyl/diphenyl and trialkyl/triphenyl derivatives of organo tin complexes containing amide functionality have been synthesized and their structural characterizations performed by different spectral techniques and computational analysis.
Isolation and Characterization of Phosphate Solubilising Rhizobia Nodulating Wild Field Pea (Pisum sativum var. abyssinicum) from Southern Tigray, Ethiopia
Authors: Gebremedhin Aklil , Assefa Fassil , Argaw Anteneh 
Published: July 2019

Hypothesis: Phosphorus is the second limiting nutrients next to nitrogen as well as the least mobile element in the soil. This nutrient is one of the major constraints for low productivity of wild field pea in the study site. Hence, the development of environmental friendly and economically accepted to subsistent farmer is undeniably important.
Aims: This experiment was initiated to isolate and characterize inorganic phosphate solubilizing rhizobia from root nodules of field pea (Pisum sativum var. abyssinicum) were characterized for their solubilisation ability on Pikovaskaya liquid and solid media.
Study Design: Laboratory experimental design was used.
Place and Duration of Study: Field pea root nodules were collected from Southern Tigray and the study was carried out between October, 2015 and June, 2016 at Haremaya University soil microbiology laboratory.
Methodology: The presumptive test, qualitative and quantitative phosphate solubilisation of isolates was done in triplicates using the standard procedures. Authentication of the isolates was made using autoclaved and sterilized river sand in pot experiment.
Results: The current results revealed that all isolates were gram negative, failed to grow on peptone glucose agar, ketolactose test and did not absorb congo-red upon incubation period. It also showed that phosphate solubilisation index of root nodulating bacteria on in vitro Pikovskaya’s agar medium varied from 1.54 to 2.70. Inorganic phosphate solubilisation in broth medium dissolved insoluble Ca3 (PO4)2 was within the range of 16.59-23.95 mg plant-1 with pH drop from 7.01 to 5.33. Among the tested rhizobia isolates, HUDRI-8 and HUDRI-25 was found to be highest phosphate solubilisation compared to the remaining isolates, served as efficient phosphate solubilizers and could be used for further test under field condition.
Conclusion: Finally, the selected isolates which are effective in N2 fixation and able to solubilise inorganic P were found to be effective in promoting nodulation and plant growth under greenhouse condition.
Knowledge, Uptake and Barriers to Pap Smear Test among Female Workers in the Rivers State University Teaching Hospital, Nigeria
Authors: Awoyesuku P. A. , Altraide B. O. A. A. , MacPepple D. A. 
Published: July 2019

Background: Early screening for cervical cancer is a key intervention in reduction of maternal deaths. Health care workers have a significant role to improve cervical cancer screening practice among women. Their attitude and practice to such an issue might positively or negatively influence people they come into contact with.
Objective: To determine the knowledge, uptake and barriers to Pap smear test among female workers in the Rivers State University Teaching Hospital.
Methodology: A hospital-based cross-sectional study was conducted between September and November 2015. A structured and pre-tested questionnaire was used to collect data from 265 female hospital workers on socio-demographic characteristics, knowledge of Pap smear, attitude towards, as well as utilization of Pap smear test. The data obtained were analyzed using SPSS version 20.0.
Results: Of the 265 respondents, 237 (89.4%) were aware of Pap smear while 28 (10.6%) had no knowledge; of those that had knowledge only 40 (16.9%) had Pap smear test done at least once previously. There is significant difference in the knowledge of Pap smear among the professionals and those with tertiary education. Common sources of information about Pap smear were Books (58.2%) and Medical Workers (50.6%). Most common reason for not wanting to be screened was No interest (43.6%).
Conclusion: Although the knowledge of Pap smear is high, the uptake is low among hospital workers. To improve utilization, public health education on the need for health workers to take up screening is crucial as it will impact positively on the general populace.
Assessment of Antiplasmodial Activity and Toxicity of Crude Extracts and Isolated Compounds from Oncoba spinosa (Flacourtiaceae)
Authors: Philip Kodi , Cheplogoi Peter Kiplagat , Elizabeth Mwangi Muthoni , Hoseah M. Akala , Langat Moses K. 
Published: July 2019

Aims: The medicinal plant Oncoba spinosa is used by the local communities in Butebo County in Eastern Uganda for treatment of malaria and other diseases. In vitro antiplasmodial activities of the crude extracts and isolated compounds were screened against chloroquine sensitive 3D7 and resistant Dd2 strains. In vivo acute toxicity of the extracts and structure elucidation were also determined in the study.
Experimental: Crude extracts of: n-hexane, dichloromethane, ethyl acetate and methanol were prepared. Isolation and purification of these extracts were done using chromatographic techniques which consisted of column and thin layer chromatography. The structures were elucidated on the basis of spectroscopic evidence. In vitro antiplasmodial activity was performed on chloroquine sensitive 3D7 and resistant Dd2 strains of Plasmodium falciparum using SYBR Green 1 assay technique. Lorke’s method of acute toxicity was used to determine the in vivo acute toxicity of the crude extracts in mice.
Results: The root ethyl acetate crude extract had highest antiplasmodial activity of IC50:4.69 ± 0.01 µg/mL and 3.52 ± 0.02 µg/mL against 3D7 and Dd2 strains respectively while the remaining three were inactive against both strains of Plasmodium. Isolation resulted in the identification of three known compounds which included: β-sitosterol, benzoic acid and chaulmoogric acid. Among the tested compounds β-sitosterol showed the highest activity of IC50 3D7: 5.51 µM. Dichloromethane and hexane extracts were non-toxic with LD50 > 5000 mg/kg while the EtOAc and MeOH extracts were slightly toxic with LD50 of 547.72 mg/kg. Statistically significance existed between the antiplasmodial activity of the crude extracts and compounds when compared with the controls at (p < 0.05). Extracts and compounds exerted a significant (P < 0.05) decrease in antiplasmodial activity compared to the positive controls.
Conclusion: The findings confirm the ethnobotanical use of O. spinosa by the local communities in Butebo County for the treatment of malaria. The results also suggest that the crude extract of this plant is safe and possesses antimalarial activity which can be used as a basis for in vivo and clinical studies to be done. Therefore the plant can offer a potential drug lead for developing a safe, effective and affordable antimalarial.
School Type and Leadership Pattern of Principals as Predictors of Science Teachers’ Job Performance in Rivers State Nigeria
Authors: Furo Pepple Tamunosisi , Ndimele Stanley 
Published: July 2019

This study, investigated the effect of school type (public and private) and leadership pattern of principal on teachers' job performance in Rivers State Nigeria. The design for the study was survey. The target population for this study comprises of all the Senior Secondary School Three (SS 3) students and their teachers in public and private Schools in Rivers State Nigeria. Simple random sampling technique was used to select 370 'respondents (60 teachers and 310 students) and, stratified random sampling was used to select twelve (12) secondary schools. Data were collected using Students' Perception of Teachers' Job Performance Questionnaire (SPTJPQ) and Teachers' Perception of School Type and Principals' Leadership Style Questionnaire (TPSTPLSQ) with 0.74 and 0.92 reliability coefficients respectively using Cronbach Alpha statistic. Three research questions guided the study, and Pearson Product Moment Correlation and Multiple Regressions were the statistical tools used for data analysis with the aid of Statistical Package for Social Science (SPSS) version 20. This study showed relationships among and between variables in terms of their direction and strength. All the variables considered in this study have relationships with the criterion variable at varying strengths. While the school type (r = -.008 p>0,05), autocratic leadership style (r = -.112 p<0.05) and laissez faire leadership style (r = -.008 p>0.05) are negatively correlated; only the autocratic leadership style had significant relationship with the criterion. The study therefore, concluded that all the variables of the study are correlated at varying strength and different direction.
Evolutionary Origin of Teeth
Authors: Rücklin Martin , Donoghue Philip CJ 
Published: July 2019

Abstract

Teeth and jaws have been widely perceived as key innovations underpinning the adaptive radiation and the evolutionary success of jawed vertebrates. However, the origin, evolution and developmental evolution of teeth are all the subject of controversy. There are three competing hypotheses that are more or less well supported by the available data: (1) the ‘outside‐in’ hypothesis which contends that odontogenic competence spread from the external dermis to the oropharynx – the traditional hypothesis based on the observation that teeth and scales exhibit common patterns of development that extend to the molecular genetic level, combined with evidence that scales appear before teeth within phylogeny; (2) the ‘inside‐out’ hypothesis that teeth and scales evolved independently, based on the observation that some jawless scale‐covered vertebrates also possess oro‐pharyngeal scales, and (3) the ‘inside and out’ hypothesis which is effectively agnostic on the question. The available evidence supports an origin of teeth through extension of odontogenic competence from the external dermis to the oropharynx.

Key Concepts

‘Outside‐in’ hypothesis argues for an evolution of teeth after the evolution of jaws from ectodermal epithelium, based on the observation that teeth and scales are considerably similar in their development and morphology.

‘Inside‐out’ hypothesis argues for an evolution of teeth before jaws from an endodermal epithelium, based on the assumption that teeth and scales are considerably different and have no common origin.

‘Inside and out’ hypothesis argues for a deep homology and ancient gene regulatory network for nonmineralised (taste buds) and mineralised appendages (scales and teeth).

Odontodes are a descriptive observation defined as hard tissue structures that develop in a single papilla, consist of dentine or dentinous tissue and frequently a superficial enameloid layer.

Whole genome duplications as drivers of vertebrate evolution enabling mutations ultimately resulting in the evolution of novelties considered as key‐innovations, e.g. jaws and teeth.

Phylogenetic congruence is a test of an evolutionary scenario with cladistics and a well‐supported phylogeny.
Why should we try to think like scientists? Scientific reasoning and susceptibility to epistemically suspect beliefs and cognitive biases
Authors: Čavojová Vladimíra , Šrol Jakub , Jurkovič Marek 
Published: July 2019

SummaryThis paper examines whether scientific reasoning skills predict people's susceptibility to epistemically suspect beliefs and cognitive biases. We used the recently developed Scientific Reasoning Scale (SRS) because it measures the ability to read and evaluate scientific evidence. Alongside the SRS, 317 participants aged 18–30 years completed measures of thinking dispositions and cognitive ability to ascertain whether the SRS contributes specifically to susceptibility to epistemically suspect beliefs and cognitive biases. Scientific reasoning correlated positively with dispositions towards analytic thinking and cognitive ability and negatively with dogmatism, epistemically suspect beliefs, and susceptibility to cognitive biases. Most importantly, it emerged as a significant predictor, contributing to susceptibility to both cognitive biases and epistemically suspect beliefs over and above the other cognitive predictors. These results provide the first empirical evidence that scientific reasoning ability is an important factor in protecting against epistemically suspect beliefs and in aiding better decision making among the non‐scientific population.
Highly Flexible and Stretchable Nanowire Superlattice Fibers Achieved by Spring‐Like Structure of Sub‐1 nm Nanowires
Authors: Zhang Simin , Lin Haifeng , Yang Haozhou , Ni Bing , Li Haoyi , Wang Xun 
Published: July 2019

AbstractConventional inorganic nanowire (NW) fibers are usually not stretchable and elastic, which may limit their practical applications. Inspired by the similarity between inorganic sub‐1 nm NWs and polymer chains in dimension, and helical spring‐like structure of cellulose in cherry bark, highly flexible and stretchable NW superlattice fibers composed of sub‐1 nm GdOOH NWs are fabricated. The NW fibers could be twined, bent, twisted, and tied without any damage. When the strain is less than 10%, the fibers present elastic deformation. The elongation at break of the fibers usually reaches ≈40–50% and the highest elongation could reach ≈86%. Excellent flexibility and stretchability of the NW fibers are attributed to the well‐aligned spring‐like NWs assembled superlattice, which are demonstrated by scanning electron microscopy tests, synchrotron small‐angle X‐ray scattering, and obvious birefringence. Moreover, NW‐nanoparticle (NP) fibers are fabricated, inspired by inorganic nanoparticle–reinforced polymers. The strength is improved compared with the NW fibers. Based on this work, it is possible to fabricate multifunctional, flexible, and stretchable inorganic NW materials composed of different inorganic sub‐1 nm NWs, which may be useful in practical applications.
An Injectable Strong Hydrogel for Bone Reconstruction
Authors: Zhao Yanran , Cui Zhiyong , Liu Bingchuan , Xiang Junfeng , Qiu Dong , Tian Yun , Qu Xiaozhong , Yang Zhenzhong 
Published: July 2019

AbstractFor treating bone defects in periarticular fractures, there is a lack of biomaterial with injectable characteristics, tough structure, and osteogenic capacity for providing a whole‐structure support and osteogenesis in the defect area. An injectable hydrogel is an ideal implant, however is weak as load‐bearing scaffolds. Herein, a new strategy, i.e., an in situ formation of “active” composite double network (DN), is raised for the preparation of an injectable strong hydrogel particularly against compression. As a demonstration, 4‐carboxyphenylboronic acid grafted poly(vinyl alcohol) (PVA) is crosslinked using calcium ions to provide a tough frame while bioactive glass (BG) microspheres are associated by poly(ethylene glycol) to obtain an interpenetrated inorganic network for reinforcement. The injected PVA/BG DN hydrogel gains compressive strength, modulus, and fracture energy of 34 MPa, 0.8 MPa, and 40 kJ m−2, respectively. Then, the properties can be “autostrengthened” to 57 MPa, 2 MPa, and 65 kJ m−2 by mineralization in 14 days. In vivo experiments prove that the injected DN hydrogel is more efficient to treat femoral supracondylar bone defects than the implanted bulk DN gel. The work suggests a facile way to obtain a strong hydrogel with injectability, cytocompatibility, and tailorable functionality.
Intrinsic Conductance of Domain Walls in BiFeO3
Authors: Zhang Yi , Lu Haidong , Yan Xingxu , Cheng Xiaoxing , Xie Lin , Aoki Toshihiro , Li Linze , Heikes Colin , Lau Shu Ping , Schlom Darrell G. , Chen Longqing , Gruverman Alexei , Pan Xiaoqing 
Published: July 2019

AbstractFerroelectric domain walls exhibit a number of new functionalities that are not present in their host material. One of these functional characteristics is electrical conductivity that may lead to future device applications. Although progress has been made, the intrinsic conductivity of BiFeO3 domain walls is still elusive. Here, the intrinsic conductivity of 71° and 109° domain walls is reported by probing the local conductance over a cross section of the BiFeO3/TbScO3 (001) heterostructure. Through a combination of conductive atomic force microscopy, high‐resolution electron energy loss spectroscopy, and phase‐field simulations, it is found that the 71° domain wall has an inherently charged nature, while the 109° domain wall is close to neutral. Hence, the intrinsic conductivity of the 71° domain walls is an order of magnitude larger than that of the 109° domain walls associated with bound‐charge‐induced bandgap lowering. Furthermore, the interaction of adjacent 71° domain walls and domain wall curvature leads to a variation of the charge distribution inside the walls, and causes a discontinuity of potential in the [110]p direction, which results in an alternative conductivity of the neighboring 71° domain walls, and a low conductivity of the 71° domain walls when measurement is taken from the film top surface.
Ligand‐Installed Nanocarriers toward Precision Therapy
Authors: Mi Peng , Cabral Horacio , Kataoka Kazunori 
Published: July 2019

AbstractDevelopment of drug‐delivery systems that selectively target neoplastic cells has been a major goal of nanomedicine. One major strategy for achieving this milestone is to install ligands on the surface of nanocarriers to enhance delivery to target tissues, as well as to enhance internalization of nanocarriers by target cells, which improves accuracy, efficacy, and ultimately enhances patient outcomes. Herein, recent advances regarding the development of ligand‐installed nanocarriers are introduced and the effect of their design on biological performance is discussed. Besides academic achievements, progress on ligand‐installed nanocarriers in clinical trials is presented, along with the challenges faced by these formulations. Lastly, the future perspectives of ligand‐installed nanocarriers are discussed, with particular emphasis on their potential for emerging precision therapies.
Homogeneous Freestanding Luminescent Perovskite Organogel with Superior Water Stability
Authors: Zhang Yucheng , Zhao Yusen , Wu Dong , Xue Jingjing , Qiu Yu , Liao Michael , Pei Qibing , Goorsky Mark S. , He Ximin 
Published: July 2019

AbstractMetal‐halide perovskites have become appealing materials for optoelectronic devices. While the fast advancing stretchable/wearable devices require stability, flexibility and scalability, current perovskites suffer from ambient‐environmental instability and incompatible mechanical properties. Recently perovskite−polymer composites have shown improved in‐air stability with the protection of polymers. However, their stability remains unsatisfactory in water or high‐humidity environment. These methods also suffer from limited processability with low yield (2D film or beads) and high fabrication cost (high temperature, air/moisture‐free conditions), thereby limiting their device integration and broader applications. Herein, by combining facile photo‐polymerization with room‐temperature in‐situ perovskite reprecipitation at low energy cost, a one‐step scalable method is developed to produce freestanding highly‐stable luminescent organogels, within which CH3NH3PbBr3 nanoparticles are homogeneously distributed. The perovskite‐organogels present a record‐high stability at different pH and temperatures, maintaining their high quantum yields for > 110 days immersing in water. This paradigm is universally applicable to broad choices of polymers, hence casting these emerging luminescent materials to a wide range of mechanical properties tunable from rigid to elastic. With intrinsically ultra‐stretchable photoluminescent organogels, flexible phosphorous layers were demonstrated with > 950% elongation. Rigid perovskite gels, on the other hand, permitted the deployment of 3D‐printing technology to fabricate arbitrary 2D/3D luminescent architectures.
Highly Efficient Light Emitting Diodes Based on In Situ Fabricated FAPbI3 Nanocrystals: Solvent Effects of On‐Chip Crystallization
Authors: Zhang Xin , Han Dengbao , Wang Chenhui , Muhammad Imran , Zhang Feng , Shmshad Ali , Xue Xulan , Ji Wenyu , Chang Shuai , Zhong Haizheng 
Published: July 2019

AbstractThe in situ fabricated perovskite nanocrystals (PNCs) obtained through spin‐coating a precursor solution are suitable candidates to achieve efficient perovskite light emitting diodes (PeLEDs). In this work, the solvent effects of on‐chip crystallization are investigated by correlating the nucleation and growth process of in situ fabricated formamidinium lead iodide (FAPbI3) nanocrystals with their optical and electronic properties. The FAPbI3 nanocrystals obtained from a precursor solution in γ‐butyrolactone (GBL) are smaller than those obtained from N,N‐dimethylformamide and dimethyl sulfoxide, and the relatively weak coordination between GBL and the precursor molecules enables reduced defect states in the resulted PNCs with enhanced photoluminescence properties. A modified LaMer model is proposed to describe the solvent effects in the on‐chip crystallization process. Based on these understandings, red emissive FA0.87Cs0.13PbI3 nanocrystal films with absolute photoluminescence quantum yields up to 70% are realized. Finally, an efficient PeLED with maximum luminance of 218 cd m−2 and peak external quantum efficiency of 15.8% is achieved with good reproducibility.