Abstract:
While fossil fuels are the primary source of energy used to power homes, busi- ness, cars, etc., its resources are rapidly decreasing as a result of broad and extensive use.${}^{1}$ Moreover, the burning of fossil fuels results in severe environmental pollution.${}^{2}$ For this reason, sustainable and environmentally friendly production of biofuels, which can be derived from...
The current environmental situation, with respect to global warming and the ever–approaching depletion of fossil fuel sources, places significance on the development of green fuel and platform chemical production methods. In this context, processes that utilise biomass sources as feedstock, are of great interest. Starchy biomass is an efficient and cost-effective source of glucose and a...
Exploitation of sustainable and renewable sources of carbon, e.g. cellulose, derived from plant matter such as wood chips, cotton or sugarcane bagasse1 and chitin, which can be isolated from sources such as molluscs, crustaceans, insects and fungi,2 is an important aspect of developing a successful bio–economy. These polymers, however, share a remarkable stability against dissolution by...
Catalytic (H3VO4 and H4V2O7) oxidative dehydrogenation (ODH) mechanistic studies of the reaction of n-hexane to 1- and 2-hexene have been conducted by means of Density Functional Theory (DFT).
The aim of this study was to gain insight about the catalytic mechanistic pathways for the conversion of n-hexane to 1- and 2-hexene. The 3-hexene pathway was omitted because the isomer is not observed...
A simplified ab initio approach is followed to model cosmic-ray (CR) modulation from first principles, using a novel time-dependent three-dimensional stochastic solver of the Parker transport equation, taking into account the various processes that modulate the intensities of these cosmic rays on their way to the inner heliosphere, and thus to Earth. This approach focuses on the effects of...
Many of the machine learning techniques that are used today involve some form of search within an
abstract space. For example, genetic algorithms search within a space consisting of solutions to the
problem at hand, whereas genetic programming searches within a program space which contains programs
that output a solution to the problem when executed. In addition...
The global threat of the Zika virus to humanity is real. Innovative and potent anti-Zika virus drugs are still at large, due to the lack of anti-Zika virus drugs that have passed phase 1 trials. Experimental research has revealed novel inhibitors of Zika virus NS5 methyltransferase enzyme. This study has taken a step further to provide insight into the molecular dynamics of Zika virus and...
Despite the ongoing research into cancer therapeutics, more than 10% of the population are still diagnosed with chronic myeloid leukemia (CML) annually. BCR-ABL protein has been identified as one of the most crucial causative targets of this disease. Inhibitors are currently available against this enzyme; however, recent studies have shown that T334I, and D381N mutations have become an unmet...
The PGMs are predominantly found in the Platreef Bushveld Complex, and the most common are Pt in the form of sperrylite (PtAs2), platarsite (PtAsS) and Pd found in the form of palladoarsenide (Pd2As) minerals. The investigations of the structural, mechanical and electronic properties of PtAs2, PtAsS and Pd2As were accomplished by employing Vienna Ab-initio Simulation Package (VASP) code at...
Iron-aluminides based alloys have created a great amount of interest due to their ability as candidates for applications in the energy sector, such as boilers, pipes, stainless Steel Coatings, automobile and aero-space industry in substitution of superalloys.
Thus, we used first-principles density functional theory to investigate the stability of FeAl and ternary FeAl-X alloys. Alloying with...
Background: The mobility of loops around the catalytic site of a protein is crucial to the catalytic activity of many proteins upon substrate binding. The proximity of these loops to the catalytic site suggests their functional mobility could influence ligand binding and catalytic activity. Dynamics of the WPD-loop is an essential determinant of the catalytic activity of tyrosine-protein...
Search problems are encountered in robotics, bioinformatics, and many other industrial
applications. Search problems of academic and practical relevance are highly complex; for instance
“if all atoms in the universe had been computing chess moves at a picosecond rate since the big
bang (if any), the analysis would be just getting started” [1]. Consequently, the design of...
The bio-synthesized DTAuNPs have an average size of 21 nm. The aggregation extent depends on the concentration of melamine, which was validated by UV–vis spectroscopy and hence a visual method for melamine detection was developed. The major observation in this method was the color change of DTAuNPs from red to purple due to the aggregation of ligand-capped gold nanoparticles initiated by...
The platinum group elements (PGEs) exist in different structures which are known and studied to some extent. The existence of these PGEs in pentlandite-like structure is a promising host phase of these PGEs. In this study Viena Ab-initio Simulation Package (VASP) density functional theory code was used to investigate phase stability of the PGEs, M9S8 (M = Ru, Pd, Os, Pt, Ir and Rh),...
HPC content
Stability of the B2 TiPd-Ir high-temperature shape memory alloys calculations were achieved by utilizing various codes in the Medea environment at the CHPC.
The structural, thermodynamic, phonon dispersion curves and elastic properties were achieved by utilizing the VASP code, CASTEP code was utilized to study the density of states of the compound.
Application code: VASP,...
The failures of transformers have been linked to the interaction of copper sulphide with copper windings. The copper sulphide is a product of copper particles that react with the corrosive sulphur within the transformer oil. This copper sulphide thereafter deposits on the vacant sites of the copper windings [1, 2].
Our research focuses on the interaction of copper sulphide on various copper...
Lithium-sulfur (Li-S) batteries are an attractive Li-ion alternative that provides large capacity
(1672 mAhg−1) and energy density (2500 Wh kg−1) while also being low cost, earth-abundant,and lightweight [1–3]. Li/S suffers from the low conductivity of S and the solubility of intermediary polysulfide species during cycling. It has been reported that Se and mixed SexSy represent an attractive...
inancial forecasting is a widely researched problem domain which is known to
be quite challenging and exhibits characteristics of uncertainty. Genetic Pro-
gramming (GP) [1] has been shown to be an effective tool for financial forecast-
ing [2]. However, the manual design of GP classification algorithms for financial
forecasting still remains the popular approach despite it being...
Emerging evidence suggests that early events in the pathogenesis of tuberculosis set the stage for the clinical outcome of the disease. An early important measure of anti-tuberculosis host responsiveness is the balance between pro-inflammatory and anti-inflammatory pathways. Leukotriene-A4 hydrolase (LTA4H) has been identified as an enzyme with dual anti- and pro-inflammatory role, thus, the...
Selective inhibition is a key focus in the design of chemotherapeutic compounds that can abrogate the oncogenic activities of major anti-apoptotic Bcl-2 proteins such as Bcl-2 and Bcl-xL. Although recent efforts have led to the development of highly selective BH3 mimetics, setbacks such as toxicities have limited their use in cancer therapy. Epigallocatechingallate (EGCG) is a non-toxic...
The performance improvement of Dye‐sensitized solar cells (DSSCs) have been the centre of research in recent years as DSSCs are of low‐cost conversion of photovoltaic energy. DSSCs uses the dye molecules adsorbed on the TiO2 semiconductor for the photon absorptions. The electronic structure and excitation properties of dye sensitizer determine the efficiency of the DSSCs. The current work...
Plasmepsins, a family of aspartic proteases expressed by Plasmodium falciparum parasite, have been identified as key mediators in the onset of lethal malaria. Precedence has been placed on this family of enzymes due their essential role in the virulence of the parasite, thus highlighting their importance as novel drug targets. A previously published study by our group proposed a set of...
PBS -P CHEM0808
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The aspartyl protease human immunodeficiency virus type 1 (HIV-1) is a 99-amino acid-long homodimer responsible for processing the Gag and Gag-Pol polyproteins into functional constituent proteins necessary for development of infectious HIV particles. Of global...
Covalent inhibition has recently gained a resurgence of interest in several drug discovery areas. The expansion of this approach is based on evidence elucidating the selectivity and potency of covalent inhibitors when bound to particular amino acids of a biological target. The Nedd4-1, an E3 ubiquitin ligase, is characterized by two covalent binding sites, of which catalytic Cyscat and...
Schistosomiasis is a debilitating disease caused by a parasitic flatworm found in freshwater. After malaria, this disease is the second most prevalent disease in Africa and is endemic in both tropical and sub-tropical regions of the world. Morbidity and mortality attributed to this disease are very high with about 240 million people infected, 800 million persons at risk of the infection and an...
Despite its technological importance, there are still many unanswered questions regarding the behaviour of defects in silicon. Oxygen, carbon and hydrogen are common impurities in Czochralski- (CZ-) grown silicon, therefore understanding the properties of ternary complexes of these impurities is technologically important. We show that the BiOi, BiCs, BiBsHi, and BiOiOi defects in silicon (Si)...
Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease of the synovial membranes affecting multiple joints and often results in extra-articular manifestations. It is characterised by joint deformation and destruction of the cartilage, ligaments and tendons. A cross-sectional meta-analysis study revealed that RA was most prevalent in the South African urban population compared to...
Nanoporous material for lithium ion batteries cathodes have currently drawn much attention than the bulk due to their improved electrochemical performances and mechanical stability. Layered-spinel lithium manganese oxides (LMOs) have also become the most desirable cathodes owing to their spontaneously great reversible capacity (302 mAh/g) and superior rate capability. Herein, we present the...
The synergetic effects of incorporating layered-spinel components as bi-functional composite cathode materials has demonstrated an improvement on the structural stability and cycling performance, making this type of composite material a viable option in advancing lithium ion batteries to cater for the growing energy demand. In particular, the...
Society or rather frustrated victims of Gender based violence have taken to Twitter as their most dependable social media platform where this situation is mostly reported.
The manifestation of this issue on Twitter is represented in keywords like rape, sexual abuse, sexual assault and sexual harassment. These keywords are held in a metadata tag known as “hashtag”, which is verifiable through...
Introduction
The oxygen reduction reaction (ORR) is particularly interesting, especially in the context of fuel cells and metal-air batteries [1,2]. The loss in cell potential at low current densities accounts for over 67% of the total potential loss and is primarily attributed to slow ORR kinetics [3]. When modelling the overall ORR activity over multifaceted Pt nanocrystallites, it is...
ABSTRACT
Tuberculosis (TB) remains one of the leading causes of mortality worldwide, it kills approximately 1.5 million people annually, while the spread of multidrug-resistant strains is of great global concern. Thus, continuous efforts to identify new anti-tubercular drugs as well as novel targets are crucial. Recently, Compounds 11426026, CDD-823953 and GSK735826A had shown to act as dual...
The failure to control tuberculosis (TB) is due to the emergence of Mycobacterium tuberculosis (Mtb) strains that multiply drug resistant toward the front line antimycobacterial drugs [1,2]. Peptidoglycan is the exoskeleton of bacterial cells and is required for their survival and growth. Among the L,d-transpeptidases (LdtMt1 to LdtMt5), any Mtb strain that lacks a functional copy of LdtMt5,...
A recent self-consistent-charge density-functional tight-binding (SCC-DFTB) set of parameters for Ti-X pairs of elements (X = Ti, O, Li) has been developed. The performance of this set has been validated with respect to TiO2 bulk polymorphs and TiO2 nanotube systems. It has been found that the band structures and geometric parameters of anatase, brookite and rutile and...
Titanium clusters is one of the central theme in cluster science to investigate the evolution of the electronic, structural and magnetic properties of the metal clusters as a function of cluster size. Small nanoclusters exhibit physical and chemical properties that are often different from the bulk phase. In particular, the titanium metal clusters have been shown to strongly dependent on their...
The first principle density functional theory approach was employed to study the effect of Ta addition on the TiPt shape memory alloys (SMAs). SMAs have the ability to remember their shapes after deformation, and this is due to their shape memory effect and super elasticity properties. They have potential to operate as high temperature shape memory alloys since they possess a reversible...
L, D transpeptidase (LdtMt2) is an essential enzyme in Mycobacterium tuberculosis (M. tuberculosis) that generate crucial peptide cross-linkages (3→3) during the biosynthesis of cell wall structure. Therefore, this enzyme has been considered as the suitable therapeutic target towards elimination of drug-resistant M. tuberculosis. The β-lactam sub-class of antibiotics, carbapenems, exhibited...
Angiotensin converting enzyme (ACE) is a zinc metalloprotease consisting of two domains with distinct physiological functions despite their 60% sequence similarity and 90% active site identity. While the C-domain controls blood pressure, the N-domain is selective for cleaving the antifibrotic N-acetyl-Ser–Asp–Lys–Pro peptide. ACE is a highly glycosylated protein (30% carbohydrates by weight)...
This research focuses on gaining better insight into the experimental reductions potentials of some selected nitrobenze and keto-enol molecules using two slightly different free energy circles.
Some of the methods used include the high computational method of G3-(MP2)-RAD and low computational methods of different DFT functionals. The applied computational methods significantly reproduced...
Thermolectric materials can convert heat into electricity and thermoelectric devices
can play an important role in the efficient use of energy. In this study, we investigate the
thermoelectric properties of the hard glassy spinel mineral CdAl2O4 . The potential of a material
to be a candidate as the active component of a thermoelectric device is captured in the figure
of merit, ZT, which...
In today’s digital age, almost every aspect of life is either supported or influenced by computer-based and information systems (i.e., the ways people communicate with each other, the cars they drive, the appliances they own, the medical facilities they visit, even the places they live and work around). The digital age leads to access control (information security) being the most interesting...
P. V. Mwonga1, S. R. Naidoo1, A. Quandt1 and K. I. Ozoemena2
1School of Physics, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg,
South Africa
2School of Chemistry, University of the Witwatersrand, Private Bag 3, Wits 2050,
Johannesburg, South Africa
E-mail: mwongav@gmail.com
Abstract
This report highlights the use defects to changes the electronic properties of...
In this study, we present a theoretical model that combines with quantum mechanical calculation theory and pKa to anticipate the degree of interaction between acid-/base –dependent species over a full range of pH conditions. To validate the theoretical model, we have the drug loading and release of a pH-responsive drug delivery system consisting of Ibuprofen an anionic Non-steroidal...
Abstract
Introduction
The Human Immunodeficiency Virus type 1 (HIV-1) protease is a crucial target for HIV/AIDS treatment and our understanding of its catalytic mechanism is the basis on which the HIV-1 enzyme inhibitors are developed. Although, several studies indicate that HIV-1 protease facilitates the cleavage of the Gag and Gag-pol polyproteins and is highly selective with regards to the...
ABSTRACT:
Introduction and literature review
One infectious disease that has had both a profound health and cultural impact on the human race in recent decades is the Acquired Immune Deficiency Syndrome (AIDS) caused by Human Immunodeficiency Virus (HIV). A major breakthrough in the treatment of HIV-1 is the use of drugs inhibiting specific enzymes necessary for the replication of the virus....
