PSG Institute of Advanced Studies

Cellulose nanofibers obtained from various plants and microbial sources, their extraction methods and various environmental applications are discussed.

The application of nanoscale materials and structures, usually ranging from 1 to 100 nanometers (nm), is an emerging area of nanoscience and nanotechnology. Synthesis of noble metal nanoparticles for applications such as catalysis, electronics, textiles, environmental protection, and biotechnology is an area of constant interest. Recently, an awareness of general sanitation, contact disease transmission, and personal protection has led to the development of antimicrobial textiles. The development of antimicrobial cotton fabrics using Zinc oxide nanoparticles has been investigated in this present work. The ZnO nanoparticles were prepared by wet chemical method and were directly applied on to the 100% cotton woven fabric using pad-dry-cure method. The antibacterial activity of the finished fabrics was assessed qualitatively by agar diffusion and parallel streak method, quantitatively by percentage reduction test. The topographical analysis of the treated fabric and untreated fabric were studied and compared. The results show that the finished fabric demonstrated significant antibacterial activity against S. aureus in both qualitative and quantitative tests. The SEM analysis revealed the embedding of ZnO nanoparticles in treated fabrics. The wash durability study of the treated fabric was also carried out and found to withstand up to 25 wash cycles. Keywords: Nanoparticles, zinc oxide, antimicrobial finish, wash durability

Hybrid ZnO@Ag core-shell nanorods were synthesized using a novel seed mediated, two-step process and their plasmon-mediated, enhanced photocatalytic property was used for degradation of industrial textile dyes and effluents.

Fungal keratitis is a serious suppurative, usually ulcerative corneal infection which may result in blindness or reduced vision. Epidemiological studies indicate that the occurrence of fungal keratitis is higher in warm, humid regions with agricultural economy. The most frequent filamentous fungal genera among the causal agents are Fusarium, Aspergillus and Curvularia. A more successful therapy of fungal keratitis relies on precise identification of the pathogen to the species level using molecular tools. As the sequence analysis of the internal transcribed spacer (ITS) region of the ribosomal RNA gene cluster (rDNA) is not discriminative enough to reveal a species-level diagnosis for several filamentous fungal species highly relevant in keratitis infections, analysis of other loci is also required for an exact diagnosis. Molecular identifications may also reveal the involvement of fungal species which were not previously reported from corneal infections. The routinely applied chemotherapy of fungal keratitis is based on the topical and systemic administration of polyenes and azole compounds. Antifungal susceptibility testing of the causal agents is of special importance due to the emergence and spread of resistance. Testing the applicability of further available antifungals and screening for new, potential compounds for the therapy of fungal keratitis are of highlighted interest.

OBJECTIVES: In this review, we aim at updating the available information on the improvement of the Hypericum perforatum L. (Hypericaceae) phytochemical profile and pharmacological properties via elicitation. KEY FINDINGS: Hypericum perforatum seedlings, shoots, roots, calli and cell suspension cultures were treated with diverse elicitors to induce the formation of secondary metabolites. The extracts of the elicitor-treated plant material containing naphthodianthrones, phloroglucinols, xanthones, flavonoids and other new compounds were quantitatively analysed and tested for their bioactivities. While hypericins were mainly produced in H. perforatum cultures containing dark nodules, namely shoots and seedlings, other classes of compounds such as xanthones, phloroglucinols and flavonoids were formed in all types of cultures. The extracts obtained from elicitor-treated samples generally possessed better bioactivities compared to the extract of control biomass. SUMMARY: Although elicitation is an excellent tool for the production of valuable secondary metabolites in H. perforatum cell and tissue cultures, its exploitation is still in its infancy mainly due to the lack of reproducibility and difficulties in scaling up biomass production.

This review elucidates the technologies in the field of exhaled breath analysis. Exhaled breath gas analysis offers an inexpensive, noninvasive and rapid method for detecting a large number of compounds under various conditions for health and disease states. There are various techniques to analyze some exhaled breath gases, including spectrometry, gas chromatography and spectroscopy. This review places emphasis on some of the critical biomarkers present in exhaled human breath, and its related effects. Additionally, various medical monitoring techniques used for breath analysis have been discussed. It also includes the current scenario of breath analysis with nanotechnology-oriented techniques.

Proton Exchange Membrane Fuel Cell (PEMFC) is majorly used for power generation without producing any emission. In PEMFC, the water generated in the cathode heavily affects the performance of fuel cell which needs better water management. The flow channel designs, dimensions, shape and size of the rib/channel, effective area of the flow channel and material properties are considered for better water management and performance enhancement of the PEMFC in addition to the inlet reactant's mass flow rate, flow directions, relative humidity, pressure and temperature. With the purpose of increasing the output energy of the fuel cell, many flow field designs are being developed continuously. In this paper, the performance of various conventional, modified, hybrid and new flow field designs of the PEMFC is studied in detail. Further the effects of channel tapering, channel bending, landing to channels width ratios, channel cross-sections and insertion of baffles/blockages/pin-fins/inserts are reviewed. The power density of the flow field designs, the physical parameters like active area, dimensions of channel/rib, number of channels; and the operating parameters like temperature and pressure are also tabulated.

Herein, we demonstrate a novel approach for development of TiO 2 grafted 2D-TiC nanosheets (TiO 2 @2D-TiC) based room temperature operable, flexible ethanol gas sensor. The homogeneous distribution, unique composition, and crystalline microstructure of TiO 2 nanoparticles grafted 2D-TiC nanosheets have been found to enhance the surface reactivity and efficiency of its transducer–receptor functions. The electron–hole recombination at the TiO 2 /2D-TiC interfaces offered superior sensor performance with fast response and recovery times. Moreover, TiO 2 @2D-TiC nanosheets based flexible sensor exhibited high selectivity toward trace-level ethanol gas (10 ppb–60 ppm) with extremely low noise-to-signal ratio and excellent stability. The results suggest that the development of low-cost flexible sensors based on TiO 2 @2D-TiC nanosheets could be applied for potential applications, such as printed/wearable electronics, biomedical sector and environmental monitoring.

Chitosan is a prominent biopolymer in research for of its physicochemical properties and uses. Each year, the number of publications based on chitosan and its derivatives increases. Because of its comprehensive biological properties, including antibacterial, antioxidant, and tissue regeneration activities, chitosan and its derivatives can be used to prevent and treat soft tissue diseases. Furthermore, chitosan can be employed as a nanocarrier for therapeutic drug delivery. In this review, we will first discuss chitosan and chitosan-based hydrogel polymers. The structure, functionality, and physicochemical characteristics of chitosan-based hydrogels are addressed. Second, a variety of characterization approaches were used to analyze and validate the physicochemical characteristics of chitosan-based hydrogel materials. Finally, we discuss the antibacterial, antibiofilm, and antifungal uses of supramolecular chitosan-based hydrogels. This review study can be used as a base for future research into the production of various types of chitosan-based hydrogels in the antibacterial and antifungal fields.

Microbial biotemplates for synthesizing inorganic nanostructures of defined morphology and size.

A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1-70.8) million) to 6.4% (58.3 (47.6-70.7) million), but is predicted to remain above the World Health Organization's Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8-38.5) million) in 2000 to 6.0% (55.5 (44.8-67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic.

Abstract Lanthanum ferrite (LaFeO 3 ) was prepared from its oxide precursors using solid state synthesis technique. Structural analysis indicate that the synthesized perovskite is phase pure having orthorhombic crystal structure with space group Pnma (62) and cell dimensions a=5.5392 Å, b=7.8573 Å, c=5.5584 Å. Morphological studies show aggregated spherical shaped nanoparticles having orthorhombic crystal structure with an average particle size of ∼ 50 nm. The LaFeO 3 modified glassy carbon electrode (GCE) was studied to determine its electrocatalytic activity towards dopamine oxidation. It is seen that the LaFeO 3 /GCE showed excellent electrocatalytic activity with a manifold increase in oxidation current compared to bare GCE. The sensing was carried out using Differential Pulse Voltammetry (DPV) wherefrom a detection limit of 10 nM and two linear regimes from 10 μM to 100 μM and 120 μM to 180 μM was deduced. The influence of ascorbic acid and uric acid in the sensing of dopamine was investigated. The estimation of dopamine in human blood samples were analyzed with excellent recovery values.

Abstract NAD is a cofactor that maintains cellular redox homeostasis and has immense industrial and biological significance. It acts as an enzymatic mediator in several biocatalytic electrochemical reactions and undergoes oxidation/reduction to form NAD + or NADH, respectively. The NAD redox couple (NAD + /NADH) mostly exists in enzyme‐assisted metabolic reactions as a coenzyme during which electrons and protons are transferred. NADH shuttles these charges between the enzyme and the substrate. In order to understand such complex metabolic reactions, it is vital to study the bio‐electrochemistry of NADH. In addition, the regeneration of NADH in industries has attracted significant attention due to its vast usage and high cost. To make biocatalysis economically viable, primary methods of NADH regeneration including enzymatic, chemical, photochemical and electrochemical methods are widely used. This review is mainly focused on the electrochemical reduction of NAD + to NADH with specific details on the mechanism and kinetics of the reaction. It provides emphasis on the different routes (direct and mediated) to electrochemically regenerate NADH from NAD + highlighting the NAD dimer formation. Also, it describes the electrocatalysts developed until now and the scope for development in this area of research.

Aquatic contamination from the accumulation of pharmaceuticals has induced severe toxicological impact to the ecological environment, especially from non-steroidal anti-inflammatory drugs (NSAIDs). Real-time monitoring of flutamide , which is a class of NSAIDs, is very significant in environmental protection. In this work, we have synthesized the hexagonal-h boron nitride decorated on bismuth oxide (Bi 2 O 3 /h-BN) based nanocomposite for the effective electrochemical detection of flutamide (FTM). The structural and morphological information of the heterostructured Bi 2 O 3 /h-BN nanocomposite was analyzed by using a sequence of characterization methods. Voltammetric techniques were used to evaluate the analytical performance of the Bi 2 O 3 /h-BN modified screen-printed carbon electrode (SPCE) for the FTM detection. The Bi 2 O 3 /h-BN modified SPCE displays a synergetic catalytic effect for the reduction of FTM due to large surface area , numerous active sites, fast charge transfer and abundant defects. The proposed electrochemical sensing platform demonstrates high selectivity, low detection limit (9.0 nM), good linear ranges (0.04–87 μM) and short response time for the detection of FTM. The feasibility of the electrochemical sensor has been proved by the successful application to determine FTM in environmental samples.

Field-effect transistor biosensors (Bio-FET) have attracted great interest in recent years owing to their distinctive properties like high sensitivity, good selectivity, and easy integration into portable and wearable electronic devices. Bio-FET performance mainly relies on the constituent components such as the bio-recognition layer and the transducer, which ensures device stability, sensitivity, and lifetime. Nanomaterial-based Bio-FETs are excellent candidates for biosensing applications. This review discusses the basic concepts, function, and working principles of Bio-FETs, and focuses on the progress of recent research in Bio-FETs in the sensing of neurotransmitters, glucose, nucleic acids, proteins, viruses, and cancer biomarkers using nanomaterials. Finally, challenges in the development of Bio-FETs, as well as an outlook on the prospects of nano Bio-FET-based sensing in various fields, are discussed.

Escalating energy demands have often ignited ground-breaking innovations in the current era of electrochemical energy storage systems. Supercapacitors (SCs) have emerged as frontrunners in this regard owing to their exclusive features such ultra-high cyclic stability, power density, and ability to be derived from sustainable sources. Despite their promising attributes, they typically fail in terms of energy density, which poses a significant hindrance to their widespread commercialization. Hence, researchers have been exploring different cutting-edge technologies to address these challenges. This review focuses on biomass-derived activated carbon (BDAC) as a promising material for SCs. Initially, the methodology and key factors involved in synthesising BDAC, including crafting the building blocks of SCs, is detailed. Further, various conventional and novel material characterization techniques are examined, highlighting important insights from different biomass sources. This comprehensive investigation seeks to deepen our understanding of the properties of materials and their significance in various applications. Next, the architectural concepts of SCs, including their construction and energy storage mechanisms, are highlighted. Finally, the translation of the unravelled BDAC metrics into promising SCs is reviewed with comprehensive device-level visualisations and quantifications of the electrochemical performance of SCs using various techniques, including cyclic voltammetry (CV), galvanostatic charge-discharge test (GCD), electrochemical impedance spectroscopy (EIS), cyclic tests (CT), voltage holding tests (VHT) and self-discharge tests (SDT). The review is concluded with a discussion that overviews peanut-shell-derived activated carbon as it is a common and promising source in our geographical setting. Overall, the review explores the current and futuristic pivotal roles of BDAC in the broad field of energy storage, especially in SC construction and commercialisation.

BACKGROUND: Six Plasmodium species are known to naturally infect humans. Mixed species infections occur regularly but morphological discrimination by microscopy is difficult and multiplicity of infection (MOI) can only be evaluated by molecular methods. This study investigated the complexity of Plasmodium infections in patients treated for microscopically detected non-falciparum or mixed species malaria in Gabon. METHODS: Ultra-deep sequencing of nucleus (18S rRNA), mitochondrion, and apicoplast encoded genes was used to evaluate Plasmodium species diversity and MOI in 46 symptomatic Gabonese patients with microscopically diagnosed non-falciparum or mixed species malaria. RESULTS: Deep sequencing revealed a large complexity of confections in patients with uncomplicated malaria, both on species and genotype levels. Mixed infections involved up to four parasite species (Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale curtisi, and P. ovale wallikeri). Multiple genotypes from each species were determined from the asexual 18S rRNA gene. 17 of 46 samples (37%) harboured multiple genotypes of at least one Plasmodium species. The number of genotypes per sample (MOI) was highest in P. malariae (n = 4), followed by P. ovale curtisi (n = 3), P. ovale wallikeri (n = 3), and P. falciparum (n = 2). The highest combined genotype complexity in samples that contained mixed-species infections was seven. CONCLUSIONS: Ultra-deep sequencing showed an unexpected breadth of Plasmodium species and within species diversity in clinical samples. MOI of P. ovale curtisi, P. ovale wallikeri and P. malariae infections were higher than anticipated and contribute significantly to the burden of malaria in Gabon.

Starch supported Cu NPs as a degradable heterogeneous catalyst for A3 coupling reaction.

Reduced graphene oxide or graphene was dispersed in ultra high molecular weight polyethylene (UHMWPE) using two methods to prepare nanocomposite films.In pre-reduction method, graphite oxide (GO) was exfoliated and dispersed in organic solvents and reduced to graphene before polymer was added, while reduction of graphene oxide was carried out after polymer addition for in situ reduction method.Raman spectroscopic study reveals that the second method results in better exfoliation of graphene but it has more amorphous content as evident from selected area electron diffraction (SAED) pattern, wide angle X-ray and differential scanning calorimetry (DSC).The nanocomposite film produced by prereduction method possesses higher crystallinity (almost the same as that of the pure film) as compared to the in situ method.It shows better modulus (increased from 864 to 1236 MPa), better strength (increased from 12.6 to 22.2 MPa), network hardening and creep resistance (creep strain reduced to 9% from 50% when 40% of maximum load was applied for 72 h) than the pure film.These findings show that graphene can be used for reinforcement of UHMWPE to improve its tensile and creep resistance properties.

The performance of ultraviolet (UV) protection, antimicrobial activity, and self-cleaning characteristics of nano titanium dioxide (TiO 2 ) with acrylic binder were assessed on the cotton fabric using pad-dry-cure method. Titanium iso-propoxide was used as precursor with two different mediums of water and ethanol to synthesize nano-sol by sol-gel technique. The synthesized nano-sol-gel was then characterized by using Fourier transform infrared (FTIR) spectroscopy, particle size analyzer (PSA), X-ray powder diffractometry (XRD), and scanning electron microscopy (SEM). The nano TiO 2 finished cotton fabrics were tested for ultraviolet protection factor (UPF), antimicrobial activity, self-cleaning action, and physical properties. The wash fastness of TiO 2 nano finished cotton fabrics for 5th, 10th, 15th, and 20th washes was assessed and also their ultra protection factor values and the percentage reduction in bacteria in each stage were reported. The self-cleaning activity was assessed for 12 hours, 24 hours, and 48 hours duration by exposing coffee stain on the specimen fabrics to sunlight. The TiO 2 nanoparticles had 12 nm when ethanol medium was used and 7 nm for water. The smaller nanoparticles had showed better results regards antimicrobial activity and self-cleaning. In case of UV-protection function it was found that the fabrics treated with 12 nm nanoparticles exhibit higher UPF values than the fabric treated with 7 nm nanoparticles. The durability of the imparted function was in the range of 32–36 washes for antimicrobial activity and UV-protection property.