bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Cyber-security Problems in Digital Assessment on Students’ Assessment Outcome: Lecturers’ Perspective
Authors: I. Eleje Lydia , C. Metu Ifeoma , C. Ikwelle Anthonia , G. Mbelede Njideka , C. Ezeugo Nneka , N. Ufearo Florence , A. Okenwa-Fadele Ijeoma , E. Ezenwosu Ngozi 
Published: August 2022

The increasing use and continuing growth of e-Learning systems has been documented by abundant studies but, little attention has been given to the cyber-security issues in digital-assessment. In fact, there are dearth of studies on research and education about lecturers’ perspective towards the influence of cyber-security problems in digital-assessment on assessment outcome. The current investigation targeted this research gap. Thus, a descriptive survey research was conducted with 200 lecturers purposively drawn from education discipline of government owned degree awarding tertiary institutions in Anambra state, Nigeria. Instrument used for data collection was an 8-item questionnaire developed by the researchers. Descriptive as well as inferential statistics were applied in the data analysis to answer one research question and two hypotheses. Analysis was by SPSS version-23. A p-value ≤0.05 was taken as significant. The results from this study revealed that cyber-security problems in digital assessment mars negatively on students’ assessment outcome. There were significant differences on lecturers’ perspective on the influence of security problems in digital-assessment on students’ assessment outcome based on level and cadre but not on gender. Cyber-security problems in digital assessment mars negatively on students’ assessment outcome and it was significantly influenced by academic level and cadre. Further research is needed to check the consistency of findings and to identify whether the relationship is causal.
Enhancing Engineering Development in Nigerian Institutions
Authors: Ujam Chinedu James 
Published: August 2022

Technical development comprises the learning of professional skills, as well as theoretical and practical engineering knowledge. Engineering departments of different universities and polytechnics in Nigeria were investigated using Pareto Analysis to understand the major causes of poor engineering development in Nigerian Institutions and ways to enhance it. The findings indicate that the major causes of poor engineering developments were poor funding, a lack of a functional policy framework, non utilization of existing laboratories, poor teaching skills, a lack of functional workshop facilities, an unstable engineering road map, a poor curriculum, decay in educational infrastructure, non-implementation of the educational budget, and poor collaboration between industries and institutions. After the analysis of all the problems hampering engineering development in Nigerian Institution using Pareto Analysis of 20/80 Rules, the result shows that the seven major causes, which mostly affected the engineering development are; Collaboration between engineering department and industries, poor teaching method, non-maximum utilization laboratories, non study of existing products and functions, lack of functional laboratories, inadequate of professional and experienced teachers, non utilization of research findings. Tackling those seven problems head-on will bring significant improvement in the development of engineering in Nigerian Institutions. Other various methods for enhancing engineering development in Nigerian institutions were stated.
Spatial Analysis of Flow Patterns to Healthcare Facilities in Kano Metropolis, Nigeria
Authors: Muibi K. H. , Babatimehin Oye 
Published: August 2022

Healthcare facilities in developing countries are most times inadequate and access to the available ones is made difficult by some uncongenial urban environmental conditions. These among other factors results in the poor health indicators normally reported for cities in developing countries. Hence, this study examined the accessibility patterns of people to healthcare facilities and factors responsible for such patterns in Kano Metropolis, Nigeria. The locations of healthcare facilities and respondents in the study area were captured through handheld GPS receivers. Also, a set of 591 questionnaires were administered to elicit information about people’s perception of healthcare facilities in the city. Spatial analyses of phenomena of interest were carried out using GIS analytical tools. Specifically, the road network was digitized with a connectivity rule from Ikonos Satellite Image and was converted to network data set. Also, the analysis of travel patterns to each healthcare facility was done using origin-destination matrix in the network analysis within the GIS environment. Results showed that the travel distance of most patients to tertiary healthcare facilities is above the WHO standard; while the travel distance to primary and secondary healthcare facilities is within the WHO standard. Furthermore, result showed disparities in the preference of people to healthcare facilities occasioned by distance, transport cost, travel time, quality of service and socio-economic factors. Approximately 62% of the household patronized hospital for treatment, 23% made use of herb and 15% engaged in self-medication. The result of this study also showed distance covered to healthcare facilities and flow patterns of healthcare users in which the distance are geometrically measured in numerical unit which has been rarely employed and these were documented in the study. The study concluded that spatial restructuring and reorganization of healthcare facilities is necessary in order to enhance access to healthcare facilities in Kano city.
Phytochemical Analysis and In-vitro Antioxidant Activities of Some Selected Higher Fungi from Oyo State, South West of Nigeria
Authors: Omeonu Francis Chukwumma , Jonathan Segun Gbolagade , Salami Adeola Temitope , Laba Sunday Ademola , Azuh Victor Okechukwu 
Published: August 2022

Higher-fungi (Hf) of the polypore mushrooms are considered to have unique secondary metabolites, making them reservoirs of therapeutically significant bioactive compounds. Phytochemical and antioxidant properties of the Hf were accessed in this study.
Four Hf, which were found in several wild locations in Oyo state, Nigeria, were collected. At the University of Ibadan Botany Department Laboratory, the species of the four Hf were determined. In-vitro antioxidant activity were assessed using the 1,1-Diphenyl-2-picrylhydrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP), and Hydrogen peroxide (H2O2) assays using methanol extracts of air-dried and powdered Hf. Results were presented as Mean SEM, graphs were created in Excel, one-way ANOVA was used for the analysis, and p ≤0.05 was regarded as significant.
These Hf were identified as Lycoperdon rimlatum (Lr) FFUI1, Trametes versicolor (Tv) FFUI2, Ganoderma lucidum (Gl) FFUI3, and Daedelia quarcina (Dq) FFUI4 and were recorded on the NCBI with accession numbers EU833664.1, JQ621899, JQ520179.1 and KP171209.1, respectively. All the Hf showed positive tests for the presence of saponin, tannin, alkaloid, terpenoid, carbohydrate,tannin and flavonoids. The Hf showed antioxidant activities, the highest DPPH inhibition was by Tv (94.48%), FRAP was by Gl (0.16 mg/g) and H2O2 inhibition was by Lr (70.90%). The antioxidant activities observed were due to the presence of useful phytochemicals making them therapeutically significant.
Demographic Profile & Pattern of Ocular and Adnexal Injuries from Sloth Bear Maul: a Study in Tertiary Centre of Bilaspur District, Chhattisgarh
Authors: Sonwani Prabha , Singh Suchita 
Published: August 2022

This study was done in all cases of bear attacked patSients admitted in our tertiary centre Chhattisgarh institute of medical science (CIMS) who suffered ocular and adnexal injuries. Sloth bear (Melursus ursinus) is found to be native in many forest areas of the state of Chhattisgarh including North Bilaspur Forest Division (NBFD). The study was conducted in the department of ophthalmology, Chhattisgarh institute of medical science (CIMS) Bilaspur Chhattisgarh for the duration of 3 years (January 2018 to December 2020). All patients who were admitted in our institute with ocular and/or adnexal injuries from bear attack have been included in this study. 27 patients were attacked by sloth bear in the forest areas of Bilaspur division and referred to our tertiary centre. These patients had ocular and adnexal injuries. These bears were found roaming in the forest areas and also at places of human and animal habitats. 67% (18 of 27) patients were attacked in the forest areas, while some were attacked in the crop fields (15%), home courtyard (7%) and near water bodies (11%). Sloth bears are one of the most aggressive bears who have attacked human populations. The injuries cause severe visual loss and disfigurement to eyeball and adnexa. Proper measures are needed to be implemented to prevent such cases in future.
Bottom‐Up Construction of Fluorene‐Based Porous Aromatic Frameworks for Ultrahigh‐Capacity and High‐Rate Alkali Metal‐Ion Batteries
Authors: Zhao Shuai , Bian Zheng , Liu Zhaoli , Wang Yinghui , Cui Fengchao , Wang Heng‐guo , Zhu Guangshan 
Published: August 2022

AbstractPorous aromatic frameworks (PAFs) have attracted much attention in various fields, yet an understanding of their applications in energy storage systems is in its infancy. Herein, a series of fluorene‐based PAFs are synthesized and then used as cation‐hosting organic anode materials in rechargeable alkali metal‐ion batteries. Experimental characterizations combined with theoretical calculations demonstrate that larger micropore volume, higher specific surface area, and more radicals can favor the redox activity and electrochemical performance of PAFs. As the anode material of lithium‐ion batteries, the optimum PAF‐202 delivers ultrahigh reversible capacity of 1152 mAh g−1 at 0.05 A g−1, impressive cyclability with 95% capacity retentions after 5000 cycles at 20 A g−1, and extraordinary high‐rate capability of 286 mAh g−1 at 10 A g−1. Moreover, PAF‐202 can also show good sodium/potassium‐ion storage properties. This study highlights the importance of building units and linking patterns of PAFs in designing high‐performance organic electrode materials for energy storage systems.
Mono‐, Di‐, and Tri‐Valent Cation Doped BiFe0.95Mn0.05O3 Nanoparticles: Ferroelectric Photocatalysts
Authors: Dubey Astita , Keat Chin Hon , Shvartsman Vladimir V. , Yusenko Kirill V. , Castillo Marianela Escobar , Buzanich Ana Guilherme , Hagemann Ulrich , Kovalenko Sergey A. , Stähler Julia , Lupascu Doru C. 
Published: August 2022

AbstractThe ferroelectricity of multivalent codoped Bismuth ferrite (BiFeO3; BFO) nanoparticles (NPs) is revealed and utilized for photocatalysis, exploiting their narrow electronic bandgap. The photocatalytic activity of ferroelectric photocatalysts BiFe0.95Mn0.05O3 (BFM) NPs and mono‐, di‐, or tri‐valent cations (Ag+, Ca2+, Dy3+; MDT) coincorporated BFM NPs are studied under ultrasonication and in acidic conditions. It is found that such doping enhances the photocatalytic activity of the ferroelectric NPs approximately three times. The correlation of the photocatalytic activity with structural, optical, and electrical properties of the doped NPs is established. The increase of spontaneous polarization by the mono‐ and tri‐valent doping is one of the major factors in enhancing the photocatalytic performance along with other factors such as stronger light absorption in the visible range, low recombination rate of charge carriers, and larger surface area of NPs. A‐site doping of BFO NPs by divalent elements suppresses the polarization, whereas trivalent (Dy3+) and monovalent (Ag+) cations provide an increase of polarization. The depolarization field in these single domain NPs acts as a driving force to mitigate recombination of the photoinduced charge carriers.
Metal–Organic Frameworks for CO2 Separation from Flue and Biogas Mixtures
Authors: Sahoo Rupam , Mondal Supriya , Mukherjee Debolina , Das Madhab C. 
Published: August 2022

AbstractGreat efforts have been made toward the separation of CO2 from flue gas and biogas to mitigate environmental pollution and the demand for renewable fuels, respectively. Nonthermal‐based separations, such as adsorption‐based or membrane‐separation technology employing porous materials, are considered to be more promising than traditional cryogenic and absorption‐based systems. Due to several advantages of metal–organic frameworks (MOFs) over other conventional porous materials, reports on flue and biogas separation by MOFs are burgeoning (423 for adsorption and 56 for membrane‐based separations until June 2021) and demand urgent summarization. This review presents a bird's eye view on such separations while organizing the developed strategies and considering several performance parameters, such as trade‐off between sorption capacity and separation selectivity in adsorption‐based systems and permeability versus separation selectivity in membrane‐based systems. In addition, the mechanisms involving such separations at the molecular level are presented. A critical discussion section offers more crucial insights into these materials from industrial deployment viewpoints. Finally, future recommendations are made for further developments of MOF materials as flue and biogas separators and thus toward solving both the challenging universal problems of global warming and energy scarcity simultaneously.
Collective Behaviors of Active Matter Learning from Natural Taxes Across Scales
Authors: Ji Fengtong , Wu Yilin , Pumera Martin , Zhang Li 
Published: August 2022

AbstractTaxis orientation is common in microorganisms, and it provides feasible strategies to operate active colloids as small‐scale robots. Collective taxes involve numerous units that collectively perform taxis motion, whereby the collective cooperation between individuals enables the group to perform efficiently, adaptively, and robustly. Hence, analyzing and designing collectives is crucial for developing and advancing microswarm toward practical or clinical applications. In this review, natural taxis behaviors are categorized and synthetic microrobotic collectives are discussed as bio‐inspired realizations, aiming at closing the gap between taxis strategies of living creatures and those of functional active microswarms. As collective behaviors emerge within a group, the global taxis to external stimuli guides the group to conduct overall tasks, whereas the local taxis between individuals induces synchronization and global patterns. By encoding the local orientations and programming the global stimuli, various paradigms can be introduced for coordinating and controlling such collective microrobots, from the viewpoints of fundamental science and practical applications. Therefore, by discussing the key points and difficulties associated with collective taxes of different paradigms, this review potentially offers insights into mimicking natural collective behaviors and constructing intelligent microrobotic systems for on‐demand control and preassigned tasks.
Fully Textured, Production‐Line Compatible Monolithic Perovskite/Silicon Tandem Solar Cells Approaching 29% Efficiency
Authors: Mao Lin , Yang Tian , Zhang Hao , Shi Jianhua , Hu Yuchao , Zeng Peng , Li Faming , Gong Jue , Fang Xiaoyu , Sun Yinqing , Liu Xiaochun , Du Junlin , Han Anjun , Zhang Liping , Liu Wenzhu , Meng Fanying , Cui Xudong , Liu Zhengxin , Liu Mingzhen 
Published: August 2022

AbstractPerovskite/silicon tandem solar cells are promising avenues for achieving high‐performance photovoltaics with low costs. However, the highest certified efficiency of perovskite/silicon tandem devices based on economically matured silicon heterojunction technology (SHJ) with fully textured wafer is only 25.2% due to incompatibility between the limitation of fabrication technology which is not compatible with the production‐line silicon wafer. Here, a molecular‐level nanotechnology is developed by designing NiOx/2PACz ([2‐(9H‐carbazol‐9‐yl) ethyl]phosphonic acid) as an ultrathin hybrid hole transport layer (HTL) above indium tin oxide (ITO) recombination junction, to serve as a vital pivot for achieving a conformal deposition of high‐quality perovskite layer on top. The NiOx interlayer facilitates a uniform self‐assembly of 2PACz molecules onto the fully textured surface, thus avoiding direct contact between ITO and perovskite top‐cell for a minimal shunt loss. As a result of such interfacial engineering, the fully textured perovskite/silicon tandem cells obtain a certified efficiency of 28.84% on a 1.2‐cm2 masked area, which is the highest performance to date based on the fully textured, production‐line compatible SHJ. This work advances commercially promising photovoltaics with high performance and low costs by adopting a meticulously designed HTL/perovskite interface.
Engineered Bacterial Outer Membrane Vesicles as Controllable Two‐Way Adaptors to Activate Macrophage Phagocytosis for Improved Tumor Immunotherapy
Authors: Feng Qingqing , Ma Xiaotu , Cheng Keman , Liu Guangna , Li Yao , Yue Yale , Liang Jie , Zhang Lizhuo , Zhang Tianjiao , Wang Xinwei , Gao Xiaoyu , Nie Guangjun , Zhao Xiao 
Published: August 2022

AbstractThe most immune cells infiltrating tumor microenvironment (TME), tumor‐associated macrophages (TAMs) closely resemble immunosuppressive M2‐polarized macrophages. Moreover, tumor cells exhibit high expression of CD47 “don't eat me” signal, which obstructs macrophage phagocytosis. The precise and efficient activation of TAMs is a promising approach to tumor immunotherapy; however, re‐education of macrophages remains a challenge. Bacteria‐derived outer membrane vesicles (OMVs) are highly immunogenic nanovesicles that can robustly stimulate macrophages. Here, an OMV‐based controllable two‐way adaptor is reported, in which a CD47 nanobody (CD47nb) is fused onto OMV surface (OMV‐CD47nb), with the outer surface coated with a polyethylene glycol (PEG) layer containing diselenide bonds (PEG/Se) to form PEG/Se@OMV‐CD47nb. The PEG/Se layer modification not only mitigates the immunogenicity of OMV‐CD47nb, thereby remarkedly increasing the dose that can be administered safely through intravenous injection, but also equips the formulation with radiation‐triggered controlled release of OMV‐CD47nb. Application of radiation to tumors in mice injected with the nanoformulation results in remodeling of TME. As two‐way adaptors, OMV‐CD47nb activates TAM phagocytosis of tumor cells via multiple pathways, including induction of M1 polarization and blockade of “don't eat me” signal. Moreover, this activation of TAMs results in the stimulation of T cell‐mediated antitumor immunity through effective antigen presentation.
Controllable Fabrication of Flexible and Foldable Carbon Nanofiber Films
Authors: Wang Xiao , Aboalhassan Ahmed A. , Zhu Chuang , Zhang Liang , Li Guang , Yan Jianhua , Yu Jianyong , Ding Bin 
Published: August 2022

AbstractCarbon nanofibers (CNFs) fabricated through traditional methods are generally composed of amorphous carbon and graphite sheets, which usually endow CNFs with high modulus and brittleness. Here, a strategy of controlling graphite sheet structures in CNFs for the scalable fabrication of silk‐like flexible CNF films that can be arbitrarily folded in any shape and can undergo thousands of dynamic bending deformation cycles is reported. In detail, the carbon precursor of polyacrylonitrile (PAN) is first electrospun into NFs and then by controlling the pre‐oxidation reaction and carbonization process to design CNFs with different graphitization degrees, flexible CNF films with tunable mechanical properties from the traditional bending resilience flexibility to truly foldable flexibility can be fabricated. Meanwhile, a correlation mechanism between microstructure and the foldable flexibility of CNFs is proposed. Importantly, it is found that manipulating the pre‐oxidation temperatures of precursor PAN NFs can effectively reduce the structural stiffness of CNFs due to the appropriate number of graphene sheets. This study provides a theoretical basis for designing truly foldable CNF films for multiple applications.
Insight into Pyroelectricity and Phase Transitions in Ferroelectrics from Nonequilibrium Approach: The Case of PbTiO3
Authors: Lynch Kelli Ann , Meng Tepie , Ponomareva I. 
Published: August 2022

AbstractComputational methodology is proposed to simulate time dependent temperature variations via thermostat approach. The methodology is applied to study pyroelectricity under nonequilibrium conditions in prototypical ferroelectric PbTiO3. It is found that at room temperature the nonequilibrium effects in pyroelectricity begin manifesting above 1.0 THz and originate from the overlap with the intrinsic soft mode frequency. Therefore, the proposed computational methodology can be used to predict equilibrium pyroelectric response by choosing a frequency of temperature variation below the intrinsic polar mode frequencies for the material. Probing the dynamics of ferroelectric phase transition with the proposed methodology revealed that it takes about a nanosecond for the computational supercell to undergo phase transition. It is concluded that computational techniques capable of simulating picoseconds can be used to compute pyroelectric response from nonequilibrium dynamical approach while those that can reach nanoseconds are suitable for simulating phase transitions in ferroelectrics.
Negative Capacitance Phenomenon and Origin in Alkali Niobate Film with Self‐Assembled Lattice Faults
Authors: Waqar Moaz , Yang Ping , He Qian , Yao Kui , Wang John 
Published: August 2022

AbstractNegative capacitance (NC) is an important phenomenon both in terms of the underlying fundamental science and its potential device application value. Achieving NC with adequate tunability in a scalable and reliable way is highly demanded for industrial applications. Herein, an electric‐field‐induced NC phenomenon and inductance‐like behavior in alkali‐deficient potassium sodium niobate thin film with self‐assembled planar faults are demonstrated. Our in‐depth investigation with the help of atomic‐scale microscopy and high‐temperature dielectric, conductivity, and X‐ray studies revealed that the compensated electronic charge at the planar faults is localized as bound polarons which convert to free polarons at high temperature as well as by an increased electric field. The collective response of such polaronic charge along the planar faults under an oscillating electric field results in the observed NC phenomenon and inductance effect. Large NC values are obtained which can be tuned in terms of magnitude and operating frequency by controlling the concentration of the free polarons via external DC bias. This work underpins the unique feature of the defect architecture obtained in the alkali deficient KNN film and provides a novel material design strategy and fundamental framework to realize NC and related exotic phenomena in defect‐engineered oxide materials.
Globally optimal design of Minimal WHEN systems using enumeration
Authors: Lin Qucheng , Liao Zuwei , Bagajewicz Miguel J. 
Published: August 2022

AbstractThe process synthesis problem referred to as work and heat exchange networks (WHENs) asks to determine the optimal heat exchanger network intertwined with compressors, expanders, and valves, all integrated into one single network, such that streams with certain initial temperature and pressure attain their temperature and pressure targets at minimum cost. This article presents a procedure that obtains the globally optimal solution of Minimal WHEN systems using an enumeration scheme, using only a few subproblems, each one solved using mathematical programming to global optimality. Minimal structures feature one compression/decompression task and one heat exchange task per stream. In addition, we depart from the ideal gas assumption and use a cubic equation of state for stream properties. Finally, the approach allows for the use of turboexpanders. Four examples are presented to show the effectiveness and accuracy of the proposed method.