bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding the Nigerian Healthcare Delivery System: A Paradox of Preventive Medicine Since the Colonial Epoch
Authors: Anthony Iroju Opeyemi 
Published: February 2019

No human society is mundane to healthcare delivery method. Apparently, the process of healthcare delivery depicts the extent of the social development of a particular society. However, the healthcare delivery process in Nigeria from the colonial era attained a new paradigm by shifting from the practice of traditional medicine to the western styled patterns. Since the colonial Nigeria, both the traditional and western medicine has been dependable sources of preventive medicine for the Nigeria populace. In spite of the outright condemnation of the traditional healthcare practices, it received unbridled patronage by a larger Nigeria populace, thus the post-independence Nigeria witnessed a paradox of health care delivery.
Aim: This paper aims to provide an understanding on the revolutions in the healthcare delivery system in Nigeria since the colonial period.
Methodology: An extensive review of literature was carried out to elicit information on the Nigerian healthcare delivery since the colonial period.
Results: The study revealed that the Nigerian healthcare delivery system is characterized by high cost. The study also showed that Nigeria has been witnessing inequitable distribution of healthcare facilities since the colonial period.
Conclusion: The healthcare delivery system in Nigeria is not a colonial invention but the advent of the colonial masters brought about an outstanding transformation in the healthcare delivery process of most Nigerian societies. Thus, the practice of preventive medicine is indigenous to the Nigerian people.
Social Polarization
Authors: Maggino Filomena , Fattore Marco 
Published: February 2019

AbstractThe term “social polarization” is used to describe a society that is composed of different socially identifiable and separate groups. Social polarization is a key feature of many modern societies and is potentially linked to conflicts, alienation, and societal tensions. When concerning income, polarization (or, more precisely, bipolarization) describes the so‐called disappearance‐of‐the‐middle‐class phenomenon, that is, the tendency of the income distribution to become U‐shaped, with the population shifting toward the two extremes of the income range, emptying the central part of it. Polarization is a different concept from inequality and requires different indexes to be measured. Many formulas exist in the statistical literature, both for univariate cardinal and ordinal variables, but there still lacks a satisfactory measurement theory for multidimensional polarization.
Random Survival Forests
Authors: Ishwaran Hemant , Lu Min 
Published: February 2019

AbstractRandom survival forests (RSF) is a flexible nonparametric tree‐ensemble method for the analysis of right‐censored survival data. In this article, we provide a short overview of RSF. We review survival splitting rules for growing random survival trees, in‐bag and out‐of‐bag (OOB) ensemble estimators, prediction performance, variable importance, and partial plots. We also briefly describe the extension of RSF to competing risks.
A Novel Bone Substitute with High Bioactivity, Strength, and Porosity for Repairing Large and Load‐Bearing Bone Defects
Authors: Li Jiao Jiao , Dunstan Colin R. , Entezari Ali , Li Qing , Steck Roland , Saifzadeh Siamak , Sadeghpour Ameneh , Field John R. , Akey Austin , Vielreicher Martin , Friedrich Oliver , Roohani‐Esfahani Seyed‐Iman , Zreiqat Hala 
Published: February 2019

AbstractAchieving adequate healing in large or load‐bearing bone defects is highly challenging even with surgical intervention. The clinical standard of repairing bone defects using autografts or allografts has many drawbacks. A bioactive ceramic scaffold, strontium‐hardystonite‐gahnite or “Sr‐HT‐Gahnite” (a multi‐component, calcium silicate‐based ceramic) is developed, which when 3D‐printed combines high strength with outstanding bone regeneration ability. In this study, the performance of purely synthetic, 3D‐printed Sr‐HT‐Gahnite scaffolds is assessed in repairing large and load‐bearing bone defects. The scaffolds are implanted into critical‐sized segmental defects in sheep tibia for 3 and 12 months, with bone autografts used for comparison. The scaffolds induce substantial bone formation and defect bridging after 12 months, as indicated by X‐ray, micro‐computed tomography, and histological and biomechanical analyses. Detailed analysis of the bone‐scaffold interface using focused ion beam scanning electron microscopy and multiphoton microscopy shows scaffold degradation and maturation of the newly formed bone. In silico modeling of strain energy distribution in the scaffolds reveal the importance of surgical fixation and mechanical loading on long‐term bone regeneration. The clinical application of 3D‐printed Sr‐HT‐Gahnite scaffolds as a synthetic bone substitute can potentially improve the repair of challenging bone defects and overcome the limitations of bone graft transplantation.
Systemic Delivery of Monoclonal Antibodies to the Central Nervous System for Brain Tumor Therapy
Authors: Han Lei , Liu Chaoyong , Qi Hongzhao , Zhou Junhu , Wen Jing , Wu Di , Xu Duo , Qin Meng , Ren Jie , Wang Qixue , Long Lixia , Liu Yang , Chen Irvin , Yuan Xubo , Lu Yunfeng , Kang Chunsheng 
Published: February 2019

AbstractAs an essential component of immunotherapy, monoclonal antibodies (mAbs) have emerged as a class of powerful therapeutics for treatment of a broad range of diseases. For central nervous system (CNS) diseases, however, the efficacy remains limited due to their inability to enter the CNS. A platform technology is reported here that enables effective delivery of mAbs to the CNS for brain tumor therapy. This is achieved by encapsulating the mAbs within nanocapsules that contain choline and acetylcholine analogues; such analogues facilitate the penetration of the nanocapsules through the brain–blood barrier and the delivery of mAbs to tumor sites. This platform technology uncages the therapeutic power of mAbs for various CNS diseases that remain poorly treated.
Integrated Perovskite/Bulk‐Heterojunction Organic Solar Cells
Authors: Liu Yongsheng , Chen Yongsheng 
Published: February 2019

AbstractThe recently emerged integrated perovskite/bulk‐heterojunction (BHJ) organic solar cells (IPOSCs) without any recombination layers have generated wide attention. This type of device structure can take the advantages of tandem cells using both perovskite solar and near‐infrared (NIR) BHJ organic solar materials for wide‐range sunlight absorption and the simple fabrication of single junction cells, as the low bandgap BHJ layer can provide additional light harvesting in the NIR region and the high open‐circuit voltage can be maintained at the same time. This progress report highlights the recent developments in such IPOSCs and the possible challenges ahead. In addition, the recent development of perovskite solar cells and NIR organic solar cells is also covered to fully underline the importance and potential of IPOSCs.
Large‐Scale Plasmonic Nanodisk Structures for a High Sensitivity Biosensing Platform Fabricated by Transfer Nanoprinting
Authors: Liang Yuzhang , Cui Wenli , Li Lixia , Yu Zhiyong , Peng Wei , Xu Ting 
Published: February 2019

AbstractSurface plasmon resonance in plasmonic nanostructures has become a powerful analytical tool in ultrasensitive label‐free biomolecule sensing. However, the fabrication of plasmonic nanostructure sensors relies on lithography‐based top‐down nanofabrication approaches, which have inherent shortcomings, such as high manufacturing cost, time‐consuming fabrication, and a small fabrication footprint. In particular, the small footprint of fabricated plasmonic nanostructures has significantly restrained the study of their angle‐dependent sensitivity. Here, a centimeter‐scale, high sensitivity sensing platform with low cost and high yield is experimentally demonstrated, fabricated through a transfer nanoprinting approach based on an ultrathin anodic aluminum oxide membrane. Two angle‐dependent resonant modes from the plasmonic nanodisk structure are observed at nonzero incidence angles. The dependence of the bulk sensitivity and surface sensitivity on the incidence angle under these two modes is systematically investigated. By functionalizing the plasmonic nanostructure, monitoring of binding of protein at dilute concentration is performed in real time at different incidence angles. The specific label‐free lowest detection limit is found to be 1.8 nanomolar for the longer wavelength resonant mode at a 10° incidence angle. This plasmonic nanostructure sensing platform should hold promise in the development of low cost and high throughput biosensing chips.
Photoinduced Lattice Symmetry Enhancement in Mixed Hybrid Perovskites and Its Beneficial Effect on the Recombination Behavior
Authors: Kim Hui‐Seon , Hagfeldt Anders 
Published: February 2019

AbstractThe strategy of mixing cations and halides in hybrid organic lead halide perovskites has recently been shown to be very successful in achieving high efficiency with long‐term perovskite solar cell stability. In this study, the effect of photoexcitation on the crystal structure of a perovskite film based on triple cations and double halides is investigated and correlated to the recombination behavior in the material. Under continuous photon excitation, a gradual increase in photoluminescence is observed from the perovskite film, coupled with a minute red‐shift. The X‐ray diffraction pattern also shows a gradual shift toward lower angles under light soaking, suggesting a photoinduced‐structural change. Noticeably, a lattice expansion occurs in a preferred orientation, which accordingly influences the crystal symmetry. The trap density of a complete perovskite solar cell is measured under continuous light. The traps are observed in the intermediate frequency, corresponding to the dielectric polarization of the bulk perovskite. A gradual decrease of the trap density is observed under light soaking accompanied by a substantial increase in photocurrent, which is in accordance with the increased recombination resistance monitored during the light soaking. The photoinduced‐structural response of the perovskite material and its resulting beneficial recombination behavior is addressed.
Fabrication of High‐Performance Biomass Derived Carbon/Metal Oxide Photocatalysts with Trilevel Hierarchical Pores from Organic–Inorganic Network
Authors: Wang He , Qu Minghuan , Wang Shulan , Liu Xuan , Li Li 
Published: February 2019

AbstractCost‐effective biomass derived carbon is considered a highly attractive energy material while high‐performance biochar based nanocomposites with well‐defined structures are very desirable candidates for this application. Herein, a novel and feasible fabrication method with renewable plane tree fluff as the carbon source is proposed to synthesize hierarchical porous titanium dioxide (TiO2)/carbon nanocomposites covering full length scales. A hybrid inorganic/organic framework with sub 10 nm feature sizes is used as the metal source for building up a high‐quality interface between phases, while bitemplates with ice and nanoscaled silica are introduced for porosity tuning. The as‐prepared TiO2/C nanocomposite presents superior photocatalytic activity for organic pollutant degradation and excellent photo‐electrochemical performance. More importantly, when loaded with a noble‐metal‐free carbide (Mo2C) prepared from a novel hydrothermal assisted fabrication route, it shows an outstanding hydrogen generation rate of 5.4 (UV) and 0.09 (visible light) mmol g−1 h−1 for water splitting, which are much better than the same sample loaded with Pt and benchmark P25. The present work proposes a dynamic and reliable tactic to synthesize a broad set of hierarchical porous metal oxide based nanocomposites, which is of far‐reaching significance for the development of sustainable technology for environmental, energy, and catalysis applications.
Stable Hierarchical Bimetal–Organic Nanostructures as HighPerformance Electrocatalysts for the Oxygen Evolution Reaction
Authors: Zhou Wei , Huang Dan‐Dan , Wu Ya‐Pan , Zhao Jun , Wu Tao , Zhang Jian , Li Dong‐Sheng , Sun Chenghua , Feng Pingyun , Bu Xianhui 
Published: February 2019

AbstractThe integration of heterometallic units and nanostructures into metal–organic frameworks (MOFs) used for the oxygen evolution reaction (OER) can enhance the electrocatalytic performance and help elucidate underlying mechanisms. We have synthesized a series of stable MOFs (CTGU‐10a1–d1) based on trinuclear metal carboxylate clusters and a hexadentate carboxylate ligand with a (6,6)‐connected nia net. We also present a strategy to synthesize hierarchical bimetallic MOF nanostructures (CTGU‐10a2–d2). Among these, CTGU‐10c2 is the best material for the OER, with an overpotential of 240 mV at a current density of 10 mA cm−2 and a Tafel slope of 58 mV dec−1. This is superior to RuO2 and confirms CTGU‐10c2 as one of the few known high‐performing pure‐phase MOF‐OER electrocatalysts. Notably, bimetallic CTGU‐10b2 and c2 show an improved OER activity over monometallic CTGU‐10a2 and d2. Both DFT and experiments show that the remarkable OER performance of CTGU‐10c2 is due to the presence of unsaturated metal sites, a hierarchical nanobelt architecture, and the Ni–Co coupling effect.
Decarboxylation with Carbon Monoxide: The Direct Conversion of Carboxylic Acids into Potent Acid Triflate Electrophiles
Authors: Kinney R. Garrison , Arndtsen Bruce A. 
Published: February 2019

AbstractWe report a new strategy for the conversion of carboxylic acids into potent acid triflate electrophiles. The reaction involves oxidative carbonylation of carboxylic acids with I2 in the presence of AgOTf, and is postulated to proceed via acyl hypoiodites that react with CO to form acid triflates. Coupling this chemistry with subsequent trapping with arenes offers a mild, room temperature approach to generate ketones directly from broadly available carboxylic acids without the use of corrosive and reactive Lewis or Bronsted acid additives, and instead from compounds that are readily available, stable, and functional group compatible.
Lutidine‐Based Chiral Pincer Manganese Catalysts for Enantioselective Hydrogenation of Ketones
Authors: Zhang Linli , Tang Yitian , Han Zhaobin , Ding Kuiling 
Published: February 2019

AbstractA series of MnI complexes containing lutidine‐based chiral pincer ligands with modular and tunable structures has been developed. The complex shows unprecedentedly high activities (up to 9800 TON; TON=turnover number), broad substrate scope (81 examples), good functional‐group tolerance, and excellent enantioselectivities (85–98 % ee) in the hydrogenation of various ketones. These aspects are rare in earth‐abundant metal catalyzed hydrogenations. The utility of the protocol have been demonstrated in the asymmetric synthesis of a variety of key intermediates for chiral drugs. Preliminary mechanistic investigations indicate that an outer‐sphere mode of substrate–catalyst interactions probably dominates the catalysis.
First Synthesis and Characterization of CH4@C60
Authors: Bloodworth Sally , Sitinova Gabriela , Alom Shamim , Vidal Sara , Bacanu George R. , Elliott Stuart J. , Light Mark E. , Herniman Julie M. , Langley G. John , Levitt Malcolm H. , Whitby Richard J. 
Published: February 2019

AbstractThe endohedral fullerene CH4@C60, in which each C60 fullerene cage encapsulates a single methane molecule, has been synthesized for the first time. Methane is the first organic molecule, as well as the largest, to have been encapsulated in C60 to date. The key orifice contraction step, a photochemical desulfinylation of an open fullerene, was completed, even though it is inhibited by the endohedral molecule. The crystal structure of the nickel(II) octaethylporphyrin/ benzene solvate shows no significant distortion of the carbon cage, relative to the C60 analogue, and shows the methane hydrogens as a shell of electron density around the central carbon, indicative of the quantum nature of the methane. The 1H spin‐lattice relaxation times (T1) for endohedral methane are similar to those observed in the gas phase, indicating that methane is freely rotating inside the C60 cage. The synthesis of CH4@C60 opens a route to endofullerenes incorporating large guest molecules and atoms.
Cyanidosilikate – Synthese und Struktur
Authors: Harloff Jörg , Michalik Dirk , Nier Simon , Schulz Axel , Stoer Philip , Villinger Alexander 
Published: February 2019

AbstractAusgehend von Fluoridosilikat‐Vorstufen in reinem Cyantrimethylsilan, Me3Si‐CN, wurde eine Reihe verschiedener Ammoniumsalze [R3NMe]+ (R=Et, nPr, nBu) mit den neuen [SiF(CN)5]2−‐ und [Si(CN)6]2−‐Dianionen in einfachen, temperaturgesteuerten F−/CN−‐Austauschreaktionen synthetisiert. Mit zersetzbaren, nicht‐unschuldigen Kationen wie [R3NH]+ konnten Metallsalze des Typs M2[Si(CN)6] (M+=Li+, K+) durch Neutralisationsreaktionen mit entsprechenden Metallhydroxiden hergestellt werden. Die ionische Flüssigkeit [BMIm]2[Si(CN)6] (Schmp.=72 °C) wurde durch eine Salzmetathesereaktion erhalten. Alle synthetisierten Salze konnten in guten Ausbeuten isoliert und vollständig charakterisiert werden.
An RNA‐Guided Cas9 Nickase‐Based Method for Universal Isothermal DNA Amplification
Authors: Wang Ting , Liu Yong , Sun Huan‐Huan , Yin Bin‐Cheng , Ye Bang‐Ce 
Published: February 2019

AbstractWe have developed an ingenious method, termed Cas9 nickase‐based amplification reaction (Cas9nAR), to amplify a target fragment from genomic DNA at a constant temperature of 37 °C. Cas9nAR employs a sgRNA:Cas9n complex with a single‐strand nicking property, a strand‐displacing DNA polymerase, and two primers bearing the cleavage sequence of Cas9n, to promote cycles of DNA replication through priming, extension, nicking, and displacement reaction steps. Cas9nAR exhibits a zeptomolar limit of detection (2 copies in 20 μL of reaction system) within 60 min and a single‐base discrimination capability. More importantly, the underlying principle of Cas9nAR offers simplicity in primer design and universality in application. Considering the superior sensitivity and specificity, as well as the simple‐to‐implement, rapid, and isothermal features, Cas9nAR holds great potential to become a routine assay for the quantitative detection of nucleic acids in basic and applied studies.
Nickel‐Catalyzed Carbofluoroalkylation of 1,3‐Enynes to Access Structurally Diverse Fluoroalkylated Allenes
Authors: Zhang Kai‐Fan , Bian Kang‐Jie , Li Chao , Sheng Jie , Li Yan , Wang Xi‐Sheng 
Published: February 2019

AbstractA nickel‐catalyzed 1,4‐carbofluoroalkylation of 1,3‐enynes to access structurally diverse fluoroalkylated allenes has been established. This method has demonstrated high catalytic reactivity, mild reaction conditions, broad substrate scope, and excellent functional‐group tolerance. The key to success is the use of a nickel catalyst to generate different fluoroalkyl radicals from readily available and structurally diverse fluoroalkyl halides to access 1,4‐difunctionalization of 1,3‐enynes by a radical relay. This strategy provides facile synthesis of structurally diverse multisubstituted allenes, and offers a solution for batch production of various fluorinated bioactive molecules for drug discovery by further transformations.
Strange Case of Signor Volta and Mister Nicholson: How Electrochemistry Developed as a Consequence of an Editorial Misconduct
Authors: Fabbrizzi Luigi 
Published: February 2019

AbstractThis Essay tells the colourful history of the invention of the pile by Alessandro Volta and of the subsequent discovery by William Nicholson of the electrolysis of water, carried out with the Voltaic pile (1800). Indeed, as a result of the dissemination of Volta's paper among London scientists, favoured by an incorrect behaviour of the President of the Royal Society, the article by Nicholson was published months before the publication of Volta's letter. The outstanding news that electricity could be generated by a simple and easy to build instrument (the pile) was printed also by daily newspapers, which favoured its spreading all over Europe and stimulated a multitude of enthusiast practitioners and amateurs to construct their own pile and to carry out the electrical decomposition of a variety of aqueous electrolytes. The correct chemical interpretation of the pile and of electrolysis had to wait for nearly one century, but in 1800 electrochemistry was born.
Targeting PAK1 with the Small Molecule Drug AK963/40708899 Suppresses Gastric Cancer Cell Proliferation and Invasion by Downregulation of PAK1 Activity and PAK1‐Related Signaling Pathways
Authors: Zhou Ying , Zhang Jian , Wang Jian , Cheng Mao‐Sheng , Zhao Dong‐Mei , Li Feng 
Published: February 2019

ABSTRACTPAK1 (p21‐activated kinase 1) is a serine/threonine protein kinase which has been initially identified as downstream effector of the Rho GTPase family. In previous research, PAK1 has been involved in the regulation of diverse cellular processes, such as cell motility, cell proliferation, gene transcription, cytoskeletal rearrangement, and cell invasion. Hyper‐activation of PAK1 was constantly observed in a variety of human cancer which make it a potential target of novel anti‐tumor drugs. To date, a great number of attentions focus on identifying the PAK1 inhibitors in medical and pharmaceutical fields. In this article, we found that a novel and potent PAK1 inhibitor, AK963/40708899, suppressed the proliferation of human gastric cancer cells significantly by downregulation of PAK1–NF‐κB–cyclinB1 pathway. In addition, AK963/40708899 inhibited the formation of filopodia and promoted cell adhesion which in turn inhibited invasive potential of gastric cells by negatively regulating PAK1–LIMKl–cofilin and PAK1–ERK–FAK pathways. Considering our result, AK963/40708899 would be a possible candidate for PAK1 targeted anti‐tumor drug. Anat Rec, 302:1571–1579, 2019. © 2019 American Association for Anatomy
Exceptional Disparity in Australian Agamid Lizards is a Possible Result of Arrival into Vacant Niche
Authors: Gray Jaimi A. , Hutchinson Mark N. , Jones Marc E.H. 
Published: February 2019

ABSTRACTAustralia provides abundant examples of continental‐scale evolutionary radiations. The collision of two continental shelves around 30 Ma facilitated an influx of squamates and the subsequent squamate radiations resulted in high taxonomic diversity. The morphological disparity seen in these major squamate groups, however, remains underexplored. Here, we examine the major cranial proportions of over 1,000 specimens using 2D linear measurements to explicitly quantify the morphological disparity of Australian agamid lizards (Amphibolurinae) and compare it to that of agamid, acrodont, and iguanian clades from other parts of the world. Our results indicate the Australian Amphibolurinae have exceptionally high cranial disparity, and we suggest that this is linked to the relaxed selective environment that greeted the founders of Amphibolurinae when they first arrived in Australia. Anat Rec, 302:1536–1543, 2019. © 2019 American Association for Anatomy
Practical stability analysis of sliding‐mode control with explicit computation of sampling time
Authors: Osinenko Pavel , Devadze Grigory , Streif Stefan 
Published: February 2019

AbstractSliding‐mode control is a wide‐spread approach to a number of practical problems. The classical stability analyses of sliding‐mode control had to face the difficulty of defining a trajectory of a system whose dynamics are discontinuous in the state variable. Different generalizations of the system trajectory were suggested, such as Filippov solutions. Another generalization is based on the sample‐and‐hold framework, where the system dynamics are in continuous time and the control is changed only at certain discrete times. The current work addresses the sample‐and‐hold stability analysis of sliding‐mode control with special attention to an explicit computation of the required controller sampling time. A computational example is provided.