This paper presents a comprehensive review of the work done, during the 1968–2005, in the application of statistical and intelligent techniques to solve the bankruptcy prediction problem faced by ...banks and firms. The review is categorized by taking the type of technique applied to solve this problem as an important dimension. Accordingly, the papers are grouped in the following families of techniques: (i) statistical techniques, (ii) neural networks, (iii) case-based reasoning, (iv) decision trees, (iv) operational research, (v) evolutionary approaches, (vi) rough set based techniques, (vii) other techniques subsuming fuzzy logic, support vector machine and isotonic separation and (viii) soft computing subsuming seamless hybridization of all the above-mentioned techniques. Of particular significance is that in each paper, the review highlights the source of data sets, financial ratios used, country of origin, time line of study and the comparative performance of techniques in terms of prediction accuracy wherever available. The review also lists some important directions for future research.
Antioxidants play important roles in the maintenance of cellular integrity and thus are critical in maintaining the homeostasis of the host immune system. A balance between the levels of pro-oxidants ...and antioxidants defines the cellular fate of genomic integrity via maintaining the redox status of the cells. An aberration in this balance modulates host immunity that affects normal cellular signaling pathways resulting in uncontrolled proliferation of cells leading to neocarcinogenesis. For decades, there have been scientific debates on the use of antioxidants for the treatment of human cancers. This review is focused on current updates on the implications of antioxidant use as adjuncts in cancer therapy with an emphasis on immunomodulation and radiosensitization.
Carbon nanotubes (CNTs) have gained much interest from academia and industry due to their unique properties that include high electrical and thermal conductivity, high mechanical strength, high ...aspect ratio, high surface area and chemical resistance. Although composite structures containing CNTs are probably the most commercially advanced applications in the market, the area that holds most promise is in electronic applications. Low temperature CVD growth of high quality CNTs can be utilized in many applications particularly next generation IoTs, wearable electronic devices, TSVs, interconnects, and sensors. CNT growth temperature generally reported in literature ranges from 600 to 1000 °C, which is not suitable for temperature sensitive substrates. However, there is ongoing research to achieve CNT growth at low temperatures, with a number reporting the growth below 550 °C. In this review, we examine and discuss various techniques and approaches adopted to achieve growth of carbon nanotubes at low temperatures and its effect on various parameters of CNTs.
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Uniform and porous graphene nanoflake films (GNFs) have been investigated as a support for catalytic Pt nanoclusters in direct methanol electro-oxidation. Pt nanoclusters of varying thickness are ...deposited on GNFs using magnetron sputtering, and their effects on the electrocatalytic activity for oxidizing methanol are systemically studied. GNF supported Pt nanoclusters with ultralow catalyst loading exhibit high performance for methanol electrocatalytic oxidation with a large mass-specific peak current density and a ratio of forward to backward peak currents up to 1.4. These characteristics compare favorably to the majority of Pt−C based electrodes, except for those of carbon nanotubes with Pt decoration on both the inner and the outer wall surfaces. The results obtained are ascribed to a highly coupled network made of high-density 2−4 nm Pt monolayer nanoclusters on both the basal and edge planes of each nanoflakes of graphene. GNFs are a promising support material for developing next-generation advanced Pt based fuel cells and their relevant electrodes in the field of energy.
Silicon has been regarded as an attractive high‐capacity anode material for next‐generation lithium‐ion batteries (LIBs). However, Si anodes suffer from huge volume variation during cycling, which ...poses a critical challenge for stable battery operation. Compared with Si, Si suboxide (SiOx) is one of the most promising candidates for high‐energy‐density LIBs because of its alleviated swelling and highly stable cycling performance. Whereas, the poor electronic conductivity and low (initial) Coulombic efficiency of SiOx anodes severely hinder practical applications for LIBs. Herein, for the first time, these issues are successfully solved through rationally designing hollow‐structured SiOx@carbon nanotubes (CNTs)/C architectures with graphitic carbon coatings and in situ growth of CNTs. When applied as anodes in LIBs, the SiOx@CNTs/C anodes exhibit high reversible capacity, high initial Coulombic efficiency (88%), outstanding cycling performance, and extraordinary mechanical strength during the calendaring process (200 MPa). This work paves the way for developing SiOx‐based anode materials for high‐energy‐density LIBs.
A hollow‐structured silicon suboxide composite (SiOx@CNTs/C) with graphitic carbon coatings and in situ growth of carbon nanotubes is successfully synthesized. The as‐prepared anode materials exhibit superior rate capability, excellent cycling stability, and extraordinary mechanical strength with high initial Coulombic efficiency as an anode in lithium‐ion batteries.
The realistic application of lithium–sulfur (Li–S) batteries has been severely hindered by the sluggish conversion kinetics of polysulfides (LiPS) and inhomogeneous deposition of Li2S at high sulfur ...loading and low electrolyte/sulfur ratio (E/S). Herein, a flexible Li–S battery architecture based on electrocatalyzed cathodes made of interfacial engineered TiC nanofibers and in situ grown vertical graphene are developed. Integrated 1D/2D heterostructured electrocatalysts are realized to enable highly improved Li+ and electron transportation together with significantly enhanced affinity to LiPS, which effectively accelerate the conversion kinetics between sulfur species, and thus induce homogeneous deposition of Li2S in the catalyzed cathodes. Consequently, highly active electro‐electrocatalysts‐based cells exhibit remarkable rate capability at 2C with a high specific capacity of 971 mAh g−1. Even at ultra‐high sulfur loading and low E/S ratio, the battery still delivers a high areal capacity of 9.1 mAh cm−2, with a flexible pouch cell being demonstrated to power a LED array at different bending angles with a high capacity over 100 cycles. This work puts forward a novel pathway for the rational design of effective nanofiber electrocatalysts for cathodes of high‐performance Li–S batteries.
Novel method was developed for in situ growth of vertical graphene with simultaneous conversion of the substrate TiO2 nanofibers into TiC ones, with well‐interconnected interfaces within the metallic VG/TiC 1D/2D heterostructured electrocatalyst enabling fast redox kinetics essential for Li–S cells. This work offers a novel avenue for the fabrication of high‐performance cathode critical to practical high‐energy‐density Li–S batteries.
Low flux and fouling are critical issues in membrane based separation processes. Here we report a two-dimensional (2D) MXene (Ti 3 C 2 T x ) modified with Ag nanoparticles (Ag@MXene) as a promising ...alternative for ultrafast water purification membrane applications. The novel Ag@MXene composite membrane with variable AgNP loadings (between 0–35%) was produced by self-reduction of silver nitrate on the surface of MXene sheets in solution, where the MXene acted simultaneously as a membrane forming material and a reducing agent. The most suitable membrane, 21% Ag@MXene with 470 nm thickness and 2.1 nm average pore size, exhibited an outstanding water flux (∼420 L m −2 h −1 bar −1 ) compared to the pristine MXene membrane (∼118 L m −2 h −1 bar −1 ) under the same experimental conditions. The 21% Ag@MXene membrane demonstrated high rejection efficiency for organic molecules with excellent flux recovery. Moreover, the 21% Ag@MXene composite membrane demonstrated more than 99% E. coli growth inhibition, while the MXene membrane exhibited only ∼60% bacteria growth inhibition compared to the control hydrophilic polyvinylidene difluoride (PVDF) based membrane. Furthermore, the 21% Ag@MXene membrane achieved favorable rejection to organic foulants like bovine serum albumin (BSA) and methyl green (MG) in comparison to other reported membranes. This combination of controlled permeability and bactericidal properties makes Ag@MXene layered nanosheets attractive candidates towards the development of nanofiltration membranes for water purification and biomedical applications.
Fractional calculus in the sky Baleanu, Dumitru; Agarwal, Ravi P.
Advances in difference equations,
02/2021, Letnik:
2021, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Fractional calculus was born in 1695 on September 30 due to a very deep question raised in a letter of L’Hospital to Leibniz. The prophetical answer of Leibniz to that deep question encapsulated a ...huge inspiration for all generations of scientists and is continuing to stimulate the minds of contemporary researchers. During 325 years of existence, fractional calculus has kept the attention of top level mathematicians, and during the last period of time it has become a very useful tool for tackling the dynamics of complex systems from various branches of science and engineering. In this short manuscript, we briefly review the tremendous effect that the main ideas of fractional calculus had in science and engineering and briefly present just a point of view for some of the crucial problems of this interdisciplinary field.
The Lotka‐Volterra (LV) system is an interesting mathematical model because of its significant and wide applications in biological sciences and ecology. A fractional LV model in the Caputo sense is ...investigated in this paper. Namely, we provide a comparative study of the considered model using Haar wavelet and Adams‐Bashforth‐Moulton methods. For the first method, the Haar wavelet operational matrix of the fractional order integration is derived and used to solve the fractional LV model. The main characteristic of the operational method is to convert the considered model into an algebraic equation which is easy to solve. To demonstrate the efficiency and accuracy of the proposed methods, some numerical tests are provided.
Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool to investigate the structure and dynamics of RNA, because many biologically important RNAs have conformationally flexible structures, ...which makes them difficult to crystallize. Functional, independently folded RNA domains, range in size between simple stem-loops of as few as 10–20 nucleotides, to 50–70 nucleotides, the size of tRNA and many small ribozymes, to a few hundred nucleotides, the size of more complex RNA enzymes and of the functional domains of non-coding transcripts. In this review, we discuss new methods for sample preparation, assignment strategies and structure determination for independently folded RNA domains of up to 100 kDa in molecular weight.
•Strategies for structure determination of RNA of different size.•NMR sample preparation, assignment strategies and structural constraints.•Hybrid techniques i.e., computational methods, cryo-EM, SAXS to supplement NMR.
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