Novel chair graphene nanotubes as adsorbing medium for alanine and asparagine amino acids - A DFT outlook.

Amino acids are required to make protein. The deficiency of amino acids leads to a lack of sleep and mood. Among various amino acids, we conducted the adsorption studies of alanine and asparagine amino acids on a novel one-dimensional material, chair graphene nanotube. The stability of the chair graphene nanotube is ensured with the negative formation energy, which is -6.490 eV/atom. The energy band gap of bare chair graphene nanotube is 1.022 eV, which possesses a semiconductor nature. The stable chair graphene nanotube is used as adsorbing material for alanine and asparagine amino acids. Besides, alanine and asparagine are physisorbed on chair graphene nanotubes that are confirmed by the range of adsorption energy from -0.107 eV to -0.718 eV. Upon adsorption of amino acids, the charge transfer outcome shows that chair graphene nanotubes behave as donors of electrons to alanine and asparagine. Further, the changes in the band gap of the chair graphene nanotube are noticed from the results of band structure and PDOS spectrum. The changes in the electron density also reveal the changes in the electronic properties of the chair graphene nanotube owing to alanine and asparagine sorption. The proposed report portrays the adsorption attributes of alanine and asparagine amino acids on 1D chair graphene nanotubes.

Recent progress on the synthesis, properties and applications of antimonene - A mini-review.

The recent advancement in group VA monolayer and few-layer materials leads to fascinating applications. In this mini-review, we present the state-of-the-art in the synthesis of antimonene, its properties and various applications. Besides, the electronic properties of antimonene depend on its allotropes. Furthermore, we studied the electronic properties of δ, ε, and twisted-θ antimonene nanosheets, nanoribbons, and nanoring, and the results are reported. Moreover, the structural stability and electronic properties of antimonene is influenced by its allotrope and nanostructure. The report will give insights into the synthesis, properties, applications, and future outlook of antimonene.

Interaction studies of propylene and butadiene on tricycle graphane nanosheet - A DFT outlook.

In this research work, we employed a tricycle graphane nanosheet as a chemical sensor to monitor the toxic hydrocarbon molecules, namely propylene, and 1,3-butadiene, which are emitted from automobile industries. At first, the structural stability and dynamical permanency of tricycle graphane is ascertained based on cohesive energy and phonon-band-spectrum. Sequentially, the electronic properties of tricycle graphane are conferred with the results of the projected density of states spectrum and band structure. The computed band gap of tricycle graphane is 5.53 eV. Chiefly, the adsorption behaviour of target propylene and 1, 3-butadiene on tricycle graphane is explored by determining adsorption energy, relative band gap variation, and Mulliken population analysis. Furthermore, the range of adsorption energy magnitudes (-0.16 eV to -1.03 eV) demonstrates that the target hydrocarbon molecules are physically adsorbed on tricycle graphane material. The overall outcome endorses that the tricycle graphane can be utilised as a prominent sensor to sense the hydrocarbon molecules released from automobiles and monitor air pollutants.

Adsorption studies of camphene and eucalyptol molecules on orthorhombic germanane nanosheet - A first-principles investigation.

In the present work, we deployed a novel orthorhombic germanane nanosheet (ortho-GeNS) as a sensing material to detect camphene and eucalyptol molecules, the indoor air pollutants in the ambient environment. In the beginning, the structural and dynamical permanency of ortho-GeNS is confirmed with cohesive energy (-4.164eV/atom) and phonon-band maps. Successively, the electronic features of ortho-GeNS are conferred using band structure along with the projected density of states maps. The energy gap of ortho-GeNS at the hybrid GGA/B3LYP level of theory is computed to be 3.948 eV. Mainly, the adsorption properties of terpinene molecules, namely camphene and eucalyptol on ortho-GeNS are investigated via ascertaining adsorption energy, Mulliken population analysis, and relative band gap variations. Besides, the scope of adsorption energy values (-0.405eVto-0.669eV) exemplifies that the target molecules are physisorbed on ortho-GeNS. Overall results suggested that the ortho-GeNS can be deployed as a worthy chemiresistive sensor to sense indoor air pollutants for monitoring indoor air quality.

Novel green phosphorene sheets to detect tear gas molecules - A DFT insight.

The green phosphorene (GP) nanosheet, one of the allotropes of layered phosphorene is employed to detect the existence of tear gas molecules. The tear gas molecules such as 1-bromo-2-butanone, bromoacetone, and bromobenzyl cyanide are examined with the service of the ATK-VNL package by employing density functional theory (DFT) method. The geometrical stability of the chief component is affirmed with the support of formation energy and electronic fingerprints of GP nanosheet like electron density, band structure, and projected density of states (PDOS) spectrum are estimated. In this research work, using DFT technique, for the first time, surface adsorption characteristics of the target molecules on GP nanosheet are explored with the assistance of adsorption energy, average energy gap variation, and Bader charge transfer, which further suggest the deployment of GP in sensing the presence of tear gas molecules.

Feasibility and acceptability of a psychosocial and adherence electronic patient reported outcomes (PROs) system at an HIV care center in southern India.

Electronic Patient Reported Outcomes (PROs), which consist of questionnaires administered directly to patients via handheld device or computer, allow for the routine and systematic capture of sensitive domains as well as longitudinal data on functional status, symptom severity, and physical and psychological well-being. There have been few examples of PROs in HIV care in low- and middle-income countries (LMICs) and none in India. We conducted a study to assess the feasibility and acceptability of PROs at the Y.R. Gaitonde Centre for AIDS Research and Education in Chennai, Tamil Nadu. We adapted an adherence and psychosocial questionnaire into an electronic PRO format and administered it to a convenience sample of 50 participants. Almost all participants indicated that the PRO questionnaire was easy to complete and understand (96%). The percentage who needed any staff help was 83% among illiterate participants but only 13% among literate participants (p<0.001). In summary, an electronic PRO questionnaire was feasible and acceptable in an HIV care center in southern India. Further study, with special attention towards optimizing PROs for persons with low literacy and limited technology experience, is needed to maximize the potential of PROs within HIV care in India.

Exploring adsorption behavior of ethylene dichloride and dibromide vapors on blue phosphorene nanosheets: A first-principles acumens.

The interrelation of toxic vapors ethylene dichloride (EDC) and ethylene dibromide (EDB) with the sensory base material blue phosphorene nanosheet (BLPNS) is studied using ab-initio method. The formational stability of BLPNS is ensured by the negative value of formation energy. Prior to the adsorption studies, we calculated the formation energy of BLPNS to ensure its stability, which is calculated to be -5.194eV/atom and found stable. The main motive behind the present work is to detect these toxic vapors using BLPNS. The intercommunication between the targeted vapors and the base material has been analyzed using the aid of adsorption energy, Bader charge transfer, energy band gap, and variation of band gap along with energy bands and DOS spectrum. The energy gap of isolated BLPNS is observed to be 1.621eV. However, the adsorption of EDC and EDB modulates the energy gap of BLPNS. The nature of assimilation is noticed to be of physisorption, which facilitates desorption of EDC and EDB molecules much easier. The successful outcome of the present research validates that BLPNS can be deployed as a prominent sensor for detection of EDC and EDB effectively.

Nitrogen mustard gas molecules and α-arsenene nanosheet interaction studies - A DFT insight.

Bis(2-chloroethyl)ethylamine (HN-1) and Bis(2-chloroethyl)methylamine (HN-2) are two classifications under the blistering agents, which are taken as target nitrogen mustard gas in the current research. α-arsenene nanosheets in its puckered configuration, are employed as a prime material to detect the above mentioned gas molecules. The chemo-sensing nature of the base material towards the target gas is ascertained with the assistance of electronic and surface assimilating attributes with the help of density functional theory technique. Initially, the geometric firmness of the base material is ensured with formation energy, which was computed to be -4.262 eV/atom, and we studied the electronic properties like the density of states spectrum, band structure, and electron density. Furthermore, surface assimilating attributes like Bader charge transfer, adsorption energy, average energy gap variation are estimated at atomistic levels using ATK-VNL package. The adsorption of nitrogen mustard gas molecules on α-arsenene nanosheets shows physisorption type of binding. The average energy gap variation of α-arsenene nanosheets upon adsorption of nitrogen mustard gas molecules ranges from 1.33 to 4.1%. Hence, the results suggest that α-arsenene nanosheets can be used as a chemical nanosensor for nitrogen mustard gas.

Exploring adsorption mechanism of hydrogen cyanide and cyanogen chloride molecules on arsenene nanoribbon from first-principles.

The SIESTA package is employed in examining the electronic and adsorption features of the toxic asphyxiants hydrogen cyanide (HCN) and cyanogen chloride (NCCl) on armchair arsenene (As-arm) nanoribbon. Based on the generalized gradient approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) level of theory, we explored the adsorption of HCN and NCCl on As-arm nanoribbon. The significant parameters necessary to validate the electronic and stable nature of As-arm nanoribbon are computed with the help of formation energy and energy gap change. The density of states (DOS) spectrum and the energy band structure are figured-out for both isolated and asphyxiants adsorbed As-arm nanoribbon, which affirms the transfer of electrons taking place between As-arm nanoribbon and the asphyxiants. Also, surface assimilating properties like Bader charge transfer, average energy gap variation, and adsorption energy are calculated for the asphyxiants adsorbed As-arm nanoribbon. Moreover, the comparison is made between the electron density of isolated and asphyxiants adsorbed As-arm nanoribbon to enunciate the utilization of As-arm nanoribbon as a chemisensor for detecting the asphyxiants HCN and NCCl molecules.

Theoretical Investigations on the Mechanism and Kinetics of OH Radical Initiated Reactions of Monochloroacetic Acid.

The oxidation mechanism of monochloroacetic acid (CH2ClCOOH) by OH radical has been systematically investigated employing quantum mechanical methods coupled with kinetic calculation using canonical variational transition state theory. Three distinct transition states were identified for the titled reaction, two corresponding to the hydrogen atom abstraction and one corresponding to the chlorine atom abstraction. The rate constants of the titled reactions are computed over the temperature range 278-350 K, and the branching ratios calculated for the hydrogen atom abstraction from the -C(O)OH site and the -CH2Cl site are 25 and 75%, respectively, at 298 K. The computed branching ratio indicates that the kinetically favorable reaction is the hydrogen atom abstraction from the -CH2Cl site resulting in the formation of CHClC(O)OH radical, which further undergoes secondary reaction with O2 and other atmospheric species. The calculated overall rate constant for the hydrogen atom abstraction reactions is in consistent with the reported experimental rate constant. The atmospheric lifetime of CH2ClCOOH is found to be around 18 days.

Facile synthesis of multifunctional silver nanoparticles using mangrove plant Excoecaria agallocha L. for its antibacterial, antioxidant and cytotoxic effects.

The current study describes a simple, rapid and eco-friendly method for the synthesis of silver nanoparticles (AgNPs) using Excoecaria agallocha (E. agallocha) leaf extract as stabilizer, bioreductant and capping agent. Synthesized AgNPs were characterized by UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). Generation of AgNPs was initially confirmed with the color change from yellow to dark brown which produces intense absorbance spectra at 440 nm in UV-Vis spectroscopy without any shifting of peaks. Further, XRD pattern confirms that the synthesized AgNPs was face centered cubic (fcc) crystalline in structure with an average size of 20 nm. On the other hand, FTIR spectrum reveals that the active metabolites like water soluble phenolic compounds, flavonoids, methylene groups, amides and carboxylate groups. These active biocompounds plays a vital role in the reduction of Ag+ into their nanoscale values, it also acts as a stabilizing and surface functionalization agent. FESEM micrographs of synthesized AgNPs shows spherical and hexagonal shaped well dispersed particles in the dimension ranging between 23 and 42 nm. EDAX confirms the presence of silver (Ag) as the major constituent element without any impurities; also substantiate the stability of generated AgNPs. The biomedical insights of nanoparticles (NPs) were assessed through radical scavenging and antibacterial properties. Additionally, synthesized AgNPs was also exhibits an excellent cytotoxic effect against human breast carcinoma cell lines (MCF-7). This study proves that synthesized AgNPs can be developed as a potential nano-drug formulation to combat pathogenic disease and also for the expansion of breast cancer therapy.

Screening of wild plant species for antibacterial activity and phytochemical analysis of Tragia involucrata L.

Eight wild plant species namely Tragia involucrata L., Cleistanthus collinus (Roxb.)Benth. Ex Hook.f., Sphaeranthus indicus L., Vicoa indica (L.) Dc., Allmania nodiflora (L.) R.Br. ex wight., Habenaria elliptica Wight., Eriocaulon thwaitesii Koern. and Evolvulus alsinoides L. were used for phytochemical extraction with four different solvents. Antibacterial activity of these plants was studied against Escherichia coli NCIM 2065 using Kirby Bauer agar disc diffusion assay. Effective antibacterial activity was shown by T. involucrata acetone extract (27.3 mm), compared to standard medicinal drug amoxicillin (28.3 mm). Minimum inhibitory concentration (MIC) of T. involucrata extract was 15 mg/mL and hence, it could be pursued further for obtaining phytomedicine. Biochemical constituents of T. involucrata fresh leaf were: sugars (55 mg/g), starch (0.7182 mg/g), proteins (0.0166 mg/g) and lipids (170 mg/g). Alkaloids, tannins, phenolic compounds, flavonoids and steroids were also observed qualitatively.

Clinical application of fluorescence endoscopic imaging using hypericin for the diagnosis of human oral cavity lesions.

BACKGROUND: Diagnosis of oral cancer is conventionally carried out using white light endoscopy and histopathology of biopsy samples. However, oral tumours are mostly superficial and the lesion and its margins can be difficult to visualise under white light. We present clinical data on fluorescence diagnostic imaging of oral lesions using hypericin, a plant-based photosensitiser. METHODS: Fluorescence images of lesions and normal tissue were captured using an endoscope after hypericin administration. The images were analysed to extract their colour parameters, which, along with the red-to-blue intensity ratios, were analysed and used to discriminate between tissue types. The results were correlated with those from histopathology. RESULTS: The red-to-blue intensity ratio increased from normal to hyperplastic to cancerous tissue and was a good parameter to discriminate between these tissue types, with sensitivity and specificity levels of 90% and above. CONCLUSION: Our results show that hypericin fluorescence imaging has the potential to be used for the clinical diagnosis of oral cancer. Further study to enhance the clinical potential of this technique includes the development of a real-time image processing and analysis system interfaced to the endoscope to enable same-day cancer diagnosis and demarcation of lesion margins in a clinical setting.

Novel photodynamic diagnosis of bladder cancer: ex vivo fluorescence cytology using hypericin.

In this study we have evaluated the use of hypericin ex vivo urine fluorescence cytology as a non-invasive method for detecting early bladder cancers. To date this is the first study reported using this technique with hypericin. Urine samples from patients with early bladder cancers were processed for fluorescence cytology by incubation with hypericin, a novel photosensitizer. Normal urine samples incubated with hypericin served as normal controls. Laser confocal microscopy and spectroscopy was used to detect the fluorescence in the exfoliated low-grade urothelial tumor cells. Fluorescence cytology was considered positive if hypericin fluorescence of the low-grade urothelial tumor cells was detected to be stronger (>8.5 times) compared to the baseline fluorescence established for normal urine samples. Automated analysis for an objective reproducible outcome appears possible. The possibility of detection of malignant urothelial cells in early cancer makes ex vivo fluorescence cytology promising for routine diagnostic screening.

A comparative study of the intestinal parasites prevalent among children living in rural and urban settings in and around Chennai.

A comparative analysis of the various intestinal parasites detected among children attending schools was carried out in a rural and urban location in and around Chennai. A total of 324 stool samples were examined by routine microscopy using normal saline and Lugol's iodine preparation as well as by saturated sodium chloride flotation technique. All suspicious samples were subjected to zinc sulphate concentration technique as well as modified Ziehl Neelson stain and Trichrome stains to identify the other uncommon intestinal parasites. Out of 125 specimens tested from the rural location, the overall prevalence of intestinal parasites was 91%. Ascaris lumbricoides was the most common helminthic parasite detected (52.8%) followed by Trichuris trichura (45.6%), Ancylostoma duodenale (37.6%), Strongyloides stercoralis (3.2%) and Hymenolepis nana (1.6%). Giardia lamblia was the most common protozoan parasite detected (16%), followed by Entamoeba histolytica (4%). In contrast under urban settings, out of the 199 stool specimens tested the positivity rate was 33%. Giardia was the most common parasite detected (22.6%) followed by Entamoeba histolytica (10.6%). All other intestinal parasites such as T. trichura (2.01%), H. nana (1.01%) and A. lumbricoides (0.50%) were found to have much lower prevalence in comparison to the rural area tested. Enterobius vermicularis (0.50%) was also detected. Ancylostoma duodenale and Strongyloides stercoralis were not encountered at all in the urban setting studied.

The ultrastructure of the tegument and clamp attachment organ of Gotocotyla bivaginalis (Monogenea, Polyopisthocotylea).

The tegument of Gotocotyla bivaginalis consists of a syncytium, perikarya and four kinds of secretory bodies, viz. electron-dense granules, moderately electron-dense vesicles, electron-lucent vesicles and large multivesicular bodies occurring in the ratio of 83:50:40:1. Microvillus-like structures, finger-like projections and a thin coat of glycocalyx occur on the In contrast, the syncytium of the clamp is relatively thin and irregularly folded, containing only three kinds of secretory bodies, viz. electron-dense granules, a few moderately electron-dense granules and several large electron-lucent vacuole-like structures in the ratio of 15:2:5. Exocytosis of the electron-dense and -lucent vesicles is apparently prevalent both in the syncytium of the haptor and general body surface. Tegumental damages induced by natural mechanical forces appear to occur in some regions of the syncytium of the clamps/haptor. Sclerites of the clamp are electron-dense and they are interconnected by the basal lamina, tendon and radial muscle fibres. Interstitial space is absent between the sarcolemma of adjacent muscle fibres of the clamp. Groups of neurons and non-myelinated nervous processes can be seen in the vicinity of the clamps. The axon is subdivided by invaginations of the neurolemma. Presumed non-ciliated mechano-receptors occur on the body surface.