Exploring Carbon Monoxide and Carbon Dioxide Adsorption on (5,5) Aluminum Nitride Nanotubes for Enhanced Sensor Applications: A DFT Study

This study examined the sensitivity of single-walled (5,5) aluminium nitride nanotubes ((5,5) AlNNTs) to carbon monoxide (CO) and carbon dioxide (CO2) gas molecules by performing DFT calculations using a hybrid functional, specifically, B3LYP (Becke's three-parameter, Lee-Yang-Parr) exchange-correlation functional at a 6-31G* basis set. This research investigates the adsorption behavior of CO2 and CO molecules on pristine and silicon-doped aluminum nitride nanotubes (AlNNTs) and examines their implications for sensor applications. The study assesses each system's adsorption energy, sensing potential, and recovery time to gain insights into their binding strength and practical viability. For CO2 adsorption on (5,5) AlNNT, significant adsorption energy of -24.36 kcal/mol was observed, indicating a strong binding to the nanotube surface, with a sensing potential of 8.95%. However, the slow recovery time of approximately 4.964 days may limit its real-time application. Si-(5,5) AlNNT exhibited a CO2 adsorption energy of -19.69 kcal/mol, a sensing potential of 5.40%, and a relatively short recovery time of approximately 2.978 min, making it a promising candidate for CO2 sensing. CO adsorption on (5,5) AlNNT showed an adsorption energy of -25.20 kcal/mol, a sensing potential of 9.095%, but a longer recovery time of approximately 20.130 days. Si-(5,5) AlNNT displayed a high CO adsorption energy of -20.78 kcal/mol, a sensing potential of 4.29%, and a recovery time of approximately 18.320 min. These findings provide insights into the adsorption characteristics of carbon molecules on AlNNTs, highlighting their potential for CO2 and CO sensing applications.

Comparative Study of Phosgene Gas Sensing Using Carbon and Boron Nitride Nanomaterials-A DFT Approach

Phosgene (COCl₂), a valuable industrial compound, maybe a public safety and health risk due to potential abuse and possible accidental spillage. Conventional techniques suffer from issues related to procedural complexity and sensitivity. Therefore, there is a need for the development of simple and highly sensitive techniques that overcome these challenges. Recent advances in nanomaterials science offer the opportunity for the development of such techniques by exploiting the unique properties of these nanostructures. In this study, we investigated the potential of six types of nanomaterials: three carbon-based ([5,0] CNT, C60, C70) and three boron nitride-based (BNNT, BN60, BN70) for the detection of COCl₂. The local density approximation (LDA) approach of the density functional theory (DFT) was used to estimate the adsorption characteristics and conductivities of these materials. The results show that the COCl₂ molecule adsorbed spontaneously on the Fullerene or nanocages and endothermically on the pristine zigzag nanotubes. Using the magnitude of the bandgap modulation, the order of suitability of the different nanomaterials was established as follows: PBN60 (0.19%) < PC70 (1.39%) < PC60 (1.77%) < PBNNT (27.64%) < PCNT (65.29%) < PBN70 (134.12%). Since the desired criterion for the design of an electronic device is increased conductivity after adsorption due to the resulting low power consumption, PC60 was found to be most suitable because of its power consumption as it had the largest decrease of 1.77% of the bandgap.

Development and Characterization of Clay-Nanocomposites for Water Purification

In this work we propose a facile method of preparing cost-effective clay-metaloxide/metal (CuO/Ag and ZnO/Ag) composite pellets for an efficient water purification technique. Clay, with intrinsic antibacterial activity, served as a membrane support for different metaloxide/Ag nanoparticles (NPs) concentrations (2.5, 5 and 10 wt.%), as the active fillers. The effect of time (24 and 48 h) on the bactericidal activity of these pellets was also monitored. The clay-nanocomposite pellets were characterized using: X-ray diffraction, X-ray fluorescence, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible (UV-Vis) spectrophotometry and nitrogen desorption analysis. The antibacterial activity performance was tested using E. coli and S. aureus strains of ATCC25922 and ATCC25923, respectively, in two aqueous media (nutrient broth and nutrient-free) by the colony-forming unit method. The results showed that the clay-CuO/Ag composite with a bandgap (1.24 eV) exhibited overall best performance under all conditions and time factors of ~100% efficiency in nutrient-free medium for all concentrations and times and 20-40% efficiency in nutrient broth for 24 h. The clay-ZnO/Ag with a bandgap of 2.88 eV showed no bactericidal activity in both media, except for that with 10 wt.% ZnO/Ag which showed 100% efficiency in nutrient-free medium after 24 h. All the synthesized composites showed 100% bactericidal efficiency in nutrient free medium after 48 h. These results indicate that, the clay/metaloxide/Ag could serve as efficient water purification technique, with a potential for large-scale commercialization.

Outwitting an Old Neglected Nemesis: A Review on Leveraging Integrated Data-Driven Approaches to Aid in Unraveling of Leishmanicides of Therapeutic Potential

The global prevalence of leishmaniasis has increased with skyrocketed mortality in the past decade. The causative agent of leishmaniasis is Leishmania species, which infects populations in almost all the continents. Prevailing treatment regimens are consistently inefficient with reported side effects, toxicity and drug resistance. This review complements existing ones by discussing the current state of treatment options, therapeutic bottlenecks including chemoresistance and toxicity, as well as drug targets. It further highlights innovative applications of nanotherapeutics-based formulations, inhibitory potential of leishmanicides, anti-microbial peptides and organometallic compounds on leishmanial species. Moreover, it provides essential insights into recent machine learning-based models that have been used to predict novel leishmanicides and also discusses other new models that could be adopted to develop fast, efficient, robust and novel algorithms to aid in unraveling the next generation of anti-leishmanial drugs. A plethora of enriched functional genomic, proteomic, structural biology, high throughput bioassay and drug-related datasets are currently warehoused in both general and leishmania-specific databases. The warehoused datasets are essential inputs for training and testing algorithms to augment the prediction of biotherapeutic entities. In addition, we demonstrate how pharmacoinformatics techniques including ligand-, structure- and pharmacophore-based virtual screening approaches have been utilized to screen ligand libraries against both modeled and experimentally solved 3D structures of essential drug targets. In the era of data-driven decision-making, we believe that highlighting intricately linked topical issues relevant to leishmanial drug discovery offers a one-stop-shop opportunity to decipher critical literature with the potential to unlock implicit breakthroughs.

Ag2CO3-halloysite nanotubes composite with enhanced removal efficiency for water soluble dyes

The release of water soluble dyes into the environment is an utmost concern in many countries. This paper presents the effects of Ag₂CO₃-halloysite composites on the efficient removal of water soluble dyes. In this study, NaHCO₃ solution was added dropwisely to halloysite nanotubes (HNTs) dispersed in aqueous AgNO₃ to form Ag₂CO₃-HNTs composite. The synthesized Ag₂CO₃-HNTs composite was characterized with Diffused Reflectance Spectroscopy (DRS), X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDX) and Fourier Transform Infra-Red (FT-IR) spectroscopy. The photocatalytic activity and the adsorption capacity of Ag₂CO₃-HNTs on methylene blue and rhodamine b dyes were dependent on pH and the amount of HNTs used in the synthesis. The photodegradation efficiency of Ag₂CO₃ was lower when compared with that of the composite material. This observation is due to the reduction in the electron-hole recombination with the HNTs acting as electron trapping site and the enhanced aqueous dispersity of Ag₂CO₃-HNTs. The enhanced adsorption of water soluble dyes by the Ag₂CO₃-HNTs resulted from the electrostatic attraction of cationic dyes to the surface of the HNTs (negatively charged). The Ag₂CO₃-HNTs therefore removed dye pollutants through a combination of photocatalytic and adsorption processes. The results obtained during the study confirmed the potential application of Ag₂CO₃-HNTs composite in water treatment technologies.

New 2D Structural Materials: Carbon-Gallium Nitride (CC-GaN) and Boron-Gallium Nitride (BN-GaN) Heterostructures-Materials Design Through Density Functional Theory

New class of ternary nanohetrostructures have been proposed by mixing 2D gallium nitride (GaN) with graphene and 2D hexagonal boron nitride (BN) with an aim towards desgining innovative 2D materials for applications in electronics and other industries. The structural stability and electronic properties of these nanoheterostructures have been analyzed using first-principles based calculations done in the framework of density functional theory. Different structure patterns have been analyzed to identify the most stable structures. It is found to be more energetically favorable that the carbon atoms occupy the positions of the nitrogen atoms in a clustered pattern in CC-GaN heterostructures, whereas boron doping is preferred in the reverse order, where isolated BN and GaN layered configurations are preferred in BN-GaN heterostructures. These 2D nanoheterostructures are energetically favored materials with direct band gap and have potential application in nanoscale semiconducting and nanoscale optoelectronic devices.

Modified halloysite nanoclay as a vehicle for sustained drug delivery

This paper presents the effect of modified halloysite nanotubes on the sustained drug release mechanisms of sodium salicylate. Acid treatment and composite polymer-halloysite modification techniques were adopted in this study. After each modification, sodium salicylate drug was loaded, and in vitro release properties were evaluated and compared with the raw unmodified halloysite nanotubes. The results obtained from SEM, TEM and FTIR analyses indicate that both acid treatment and composite formation have no effect on the tubular structure and morphology of halloysite. However, modification of the halloysite nanotubes did influence the drug release rate. In the acid treatment modification, there was an improved loading of sodium salicylate drug which resulted in the sustain release of large amount of the sodium salicylate. In the polymer/halloysite composite formation, a consistent layer of polymer was formed around the halloysite during the composite formation and thus delayed release providing sustained release of sodium salicylate drug over a longer period of time as compared to the acid treated and unmodified halloysite. The results from the invitro release were best fitted with the Higuchi and the Koresymer-Peppas models.

Electronic interaction in composites of a conjugated polymer and carbon nanotubes: first-principles calculation and photophysical approaches

The mechanisms that control the photophysics of composite films made of a semiconducting conjugated polymer (poly(paraphenylene vinylene), PPV) mixed with single-walled carbon nanotubes (SWNT) up to a concentration of 64 wt % are determined by using photoexcitation techniques and density functional theory. Charge separation is confirmed experimentally by rapid quenching of PPV photoluminescence and changes in photocurrent starting at relatively low concentrations of SWNT. Calculations predict strong electronic interaction between the polymer and the SWNT network when nanotubes are semiconducting.

Variable Number Tandem Repeat (VNTR) analysis reveals genetic diversity within Mycoplasma mycoides mycoides small colony isolates from Nigeria

A Variable Number Tandem Repeat (VNTR) analysis was conducted on thirteen (13) M. mycoides mycoides Small Colony isolates from Nigeria using Tandem Repeat (TR) 34 which is a predicted lipoprotein located within the hypothetical protein MAG6170. The analysis revealed diversity within the M. mycoides mycoides Small Colony isolates with five different VNTR types indicated. Some correlation was determined between the VNTR types and their geographical origin. VNTR analysis may represent a useful, rapid first-line test for use in molecular epidemiological analysis of M. mycoides mycoides Small Colony for possible outbreak tracing and disease control.

Gamma interferon-producing CD4 T-cells correlate with resistance to Mycoplasma mycoides subsp. mycoides S.C. infection in cattle

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC), is one of the most significant cattle disease in Africa. The control measures, which led to eradication from numerous countries are not feasible in Africa where the only prophylaxis relies on vaccination. However, the attenuated vaccines, used up to now in Africa, are of low efficiency. The development of an improved vaccine is, therefore, a necessity. The purpose of this study was to compare some immunological parameters in MmmSC-infected cattle (endobronchial versus natural in-contact infection) and assess the response in correlation with the clinical outcome (death versus recovery). Characterization of the immune parameters elicited in recovered animals, known to be refractory to new infection, will be an important step towards development of new vaccines against CBPP. A significant outcome of this study was the demonstration that all MmmSC-infected cattle developed a MmmSC-specific cell-mediated immune response. A kinetic analysis of the MmmSC responsiveness showed that the main difference between endobronchially- and in-contact infected animals was the delay before the onset of the MmmSC-specific immune response. The first MmmSC-responding PBMC sample was selected from each animal for cell phenotyping. The phenotypic analysis of this early MmmSC-induced response revealed the predominant contribution of the CD4 T-cells in all animals whereas IFNgamma was only constantly produced in recovered animals. Evolution of this early MmmSC-specific immune response was then followed by a kinetic analysis of the MmmSC-induced CD4 T-cell response and IFNgamma released. The results demonstrated that in recovered animals, the MmmSC-specific CD4 Th1-like T-cell response was maintained until slaughtering whereas in animals with acute disease, progression of CBPP was associated with a decreased ability of the PBMC to produce IFNgamma. The results led to the identification of immune parameters, which correlate with protection against CBPP and to a relevant strategy for the development of improved vaccines against this disease.

Contagious bovine pleuropneumonia. A reassessment of the efficacy of vaccines used in Africa

Contagious bovine pleuropneumonia is a major threat for cattle in Africa. Since 1956 the T1/44 strain has been used as a vaccine, and later on, T1sr, a streptomycin-resistant variant that gives fewer post-vaccinal reactions had been developed. These vaccines are known not to be very efficient but they normally should provide protection for about eight months. However, recent emergency vaccinations, performed in various countries in the southern part of the continent apparently met with failure, casting doubts on the identity as well as the protection afforded by the T1sr strain. A vaccine trial has been designed to reassess the real protection afforded by these vaccines in face of recently isolated pathogenic strains. Great care has been taken to test the original vaccinal strains at a dose corresponding to the minimum requirement by international standards. The test was performed in Cameroon, Kenya, and Namibia as to take into account the genetic diversity that exists among the pathogenic strains. In those conditions, the protection rate at three months varied from 33 to 67%, whatever the strain used, T1/44 or T1sr. These results call for additional research for vaccine development and careful planning of strategies in the fight against CBPP.