Deepak Rawtani

Bioindicators: the natural indicator of environmental pollution

ABSTRACT Bioindicators are living organisms such as plants, planktons, animals, and microbes, which are utilized to screen the health of the natural ecosystem in the environment. They are used for assessing environmental health and biogeographic changes taking place in the environment. Each organic entity inside a biological system provides an indication regarding the health of its surroundings such as plankton responding rapidly to changes taking place in the surrounding environment and serving as an important biomarker for assessing the quality of water as well as an indicator of water pollution. Even the health of aquatic flora is best reflected by plankton, which acts as an early warning signal. In this review we have tried to explain the concept behind Bioindicators and plankton, with particular emphasis on their potential to be used as Bioindicators for water quality assessment and outcomes relating to this.

Emerging Strategies and Applications of Layer-by-layer Self-Assembly

Layer-by-layer self-assembly is an approach to develop an ultrathin film on solid support by alternate exposure to positive and negative species with spontaneous deposition of the oppositely charged ions. This paper summarizes various approaches used for fabrication of layer-by-layer self-assembly as well as their utility to produce various devices. The layer-by-layer technique is basically used for formation of multilayer films. A variety of nanomaterials use it for the modification of films to enhance their resultant durability as well as strength. Studies have shown that many different types of materials can be used for fabrication of multilayers. Recently the layer-by-layer self-assembly technique has also been used for fabrication of gas sensors, hydrogen sensors and solar-based cells. Various methods, such as spin deposition, calcinations, and dry-transfer printing are being used for fabrication of thin films. In this review, the author summarizes the various interesting properties as well as fabrication strategies of layer-by-layer self-assembly.

Assessment of Drinking Water Quality and its Health Effects in Rural Areas of Harij Taluka, Patan District of Northern Gujarat

ABSTRACT The most important resource for the survival of human beings is the availability of fresh drinking water. This study compares the drinking water quality in nine villages of Harij Taluka of Patan District of Northern Gujarat. Samples were collected from various village drinking water sources and analyzed. Along with this scientific analysis, a socioeconomic survey of village households was conducted. The water samples were analyzed for parameters crucial for drinking water quality, such as TDS (total disolved solids), fluoride, dissolved oxygen, magnesium hardness, chloride, and many others. The findings from the scientific analysis of water and from the survey revealed that although some parameters in water exceed their normal tolerance, it does not have any significant impact on human health. The article thus concludes that the water quality is good for human consumption as laboratory analysis of the samples revealed no significant contamination.

Nanotechnology-based recent approaches for sensing and remediation of pesticides

Pesticides are meant to control and destroy the pests and weeds. They are classified into different categories on the basis their origin and type of pest they target. Chemical pesticides such as insecticides, herbicides and fungicides are commonly used in agricultural fields. However, the excessive use of these agrochemicals have adverse effects on environment such as reduced population of insect pollinators, threat to endangered species and habitat of birds. Upon consumption; chemical pesticides also cause various health issues such as skin, eye and nervous system related problems and cancer upon prolonged exposure. Various techniques in the past have been developed on the basis of surface adsorption, membrane filtration and biological degradation to reduce the content of pesticides. However, slow response, less specificity and sensitivity are some of the drawbacks of such techniques. In recent times, Nanotechnology has emerged as a helping tool for the sensing and remediation of pesticides. This review focuses on the use of this technology for the detection, degradation and removal of pesticides. Nanomaterials have been classified into nanoparticles, nanotubes and nanocomposites that are commonly used for detection, degradation and removal of pesticides. The review also focuses on the chemistry behind the sensing and remediation of pesticides using nanomaterials. Different types of nanoparticles, viz. metal nanoparticles, bimetallic nanoparticles and metal oxide nanoparticles; nanotubes such as carbon nanotubes and halloysite nanotubes have been used for the detection, degradation and removal of pesticides. Further, various enzyme-based biosensors for detection of pesticides have also been summarized.

Aspects of Nanoelectronics in Materials Development

Nanotechnology is an enabling technology that potentially impacts all aspects of the chip-making practice from materials to devices, to circuits, and to system-level architecture. Nanoelectronics is an interdisciplinary division which refers to the use of nanotechnology in electronic components. The materials and devices used in nanoe‐ lectronics are so small that the interatomic interactions and quantum mechanical properties of such materials need to be studied extensively. Various electronic devices manufactured at nanoscale have been established: devices having negative differen‐ tial resistance, switches which can be electrically configured, tunneling junctions, carbon nanotube (CNT) transistor, and unimolecular transistor. Some devices have also been linked together to form circuits proficient of performing functions such as logic functions and basic memory. Some of the widely used materials in nanoelectronics include zero-dimensional materials like quantum dots; one-dimensional materials like nanotubes and nanowires; nanoclusters and nanocomposites; carbon-based materials like carbon nanotubes (CNTs), fullerenes and graphene; etc. Plastic C nanoelectronics is also a prominent research area with collaboration between the materials science, chemistry, physics, nanotechnology, and engineering communities. As one of the most promising contenders, C nanostructures, either 2D graphene or quasi-1D CNTs, have unlocked entirely new standpoints concerning the C-based electronics. This chapter focuses on the approaches of nanotechnology toward nanoelectronics, materials used in nanoelectronics and the applications of nanoelectronics related to carbon-based materials in the field of thin-film transistors, printed electronics (PE), artificial skin and muscle, wearable electronics, flexible gas sensors, multifunctional and responsive elastomers, and plastic solar panels.

INTERACTION OF METHOTREXATE WITH DNA USING GOLD NANOPARTICLES AS A PROBE

□ The use of gold nanoparticles as a probe to investigate the interaction of DNA with methotrexate is reported. Methotrexate has widespread use in the treatment of tumors and auto-immune diseases, and is an anti-metabolite of folic acid, having a direct or indirect effect on various molecular targets, which influences DNA replication and cell proliferation by integrating between the spaces between adjacent DNA base pairs. A simple method to monitor the interaction of DNA with methotrexate was developed, using ultraviolet – visible spectroscopy and spectroflurometry with gold nanoparticles as the probe. In a mixture of DNA and methotrexate, as the proportion of free DNA increased, the absorption of gold nanoparticles decreased and the fluorescence intensity increased. This article confirmed that as the interaction between DNA and methotrexate increased, less free DNA was available to bind with gold nanoparticles present in solution, reducing the absorption and enhancing the fluorescence of the nanoparticles. The limit of detection and limit of quantification were 160 ng/mL and 50 ng/mL, respectively. The results demonstrated the use of gold nanoparticles as a probe for the interaction of DNA with methotrexate, which may be an important tool to measure drug-induced DNA damage.

Fabrication routes for one-dimensional nanostructures via block copolymers

Nanotechnology is the field which deals with fabrication of materials with dimensions in the nanometer range by manipulating atoms and molecules. Various synthesis routes exist for the one, two and three dimensional nanostructures. Recent advancements in nanotechnology have enabled the usage of block copolymers for the synthesis of such nanostructures. Block copolymers are versatile polymers with unique properties and come in many types and shapes. Their properties are highly dependent on the blocks of the copolymers, thus allowing easy tunability of its properties. This review briefly focusses on the use of block copolymers for synthesizing one-dimensional nanostructures especially nanowires, nanorods, nanoribbons and nanofibers. Template based, lithographic, and solution based approaches are common approaches in the synthesis of nanowires, nanorods, nanoribbons, and nanofibers. Synthesis of metal, metal oxides, metal oxalates, polymer, and graphene one dimensional nanostructures using block copolymers have been discussed as well.

Multifarious applications of atomic force microscopy in forensic science investigations

Forensic science is a wide field comprising of several subspecialties and uses methods derived from natural sciences for finding criminals and other evidence valid in a legal court. A relatively new area; Nano-forensics brings a new era of investigation in forensic science in which instantaneous results can be produced that determine various agents such as explosive gasses, biological agents and residues in different crime scenes and terrorist activity investigations. This can be achieved by applying Nanotechnology and its associated characterization techniques in forensic sciences. Several characterization techniques exist in Nanotechnology and nano-analysis is one such technique that is used in forensic science which includes Electron microscopes (EM) like Transmission (TEM) and Scanning (SEM), Raman microscopy (Micro -Raman) and Scanning Probe Microscopes (SPMs) like Atomic Force Microscope (AFM). Atomic force microscopy enables surface characterization of different materials by examining their morphology and mechanical properties. Materials that are immeasurable such as hair, body fluids, textile fibers, documents, polymers, pressure sensitive adhesives (PSAs), etc. are often encountered during forensic investigations. This review article will mainly focus on the use of AFM in the examination of different evidence such as blood stains, forged documents, human hair samples, ammunitions, explosives, and other such applications in the field of Forensic Science.

Azeotropic mixture used for development and validation of Lornoxicam in bulk and its tablet dosage form by spectrophotometric method

A novel, safe, economic and sensitive method of spectrophotometric estimation has been developed using Azeoptropic mixture (water:methanol: 60:40, v/v) for the quantitative determination of Lornoxicam, a practically water-insoluble drug. Hence, Lornoxicam stock solution was prepared in Azeoptropic mixture. Lornoxicam showed maximum absorbance at 383 nm. Beers law was obeyed in the concentration range 4–24 μg/mL with regression coefficient of 0.999. The method was validated in terms of linearity (R2=0.999), precision (CV for intra-day and inter-day was 0.28–0.68 and 0.12–0.92, respectively), accuracy (98.03–100.59% w/w) and specificity. This method is simple, precise, accurate, sensitive and reproducible and can be used for the routine quality control testing of the marketed formulations.

Behavior of malachite green with different adsorption matrices

Malachite green (MG) has an extensive use as a biocide in aquaculture industries throughout the world. It is found to be highly effective against protozoal and fungal infections, besides being used as colorant for textiles and coloring additives in packed foods and fish industries. Aquaculture industries have used MG for topical applications by bath or flush methods, without giving due attention to the fact that in topical application, the therapeutants might be absorbed systemically and may produce significant internal effects. The presence of nitrogen in the ring structure of MG makes it a very controversial compound as it poses risks to those who consume MG-exposed fishes; it also causes subsequent detrimental effects to the immune system by genotoxicity and carcinogenesis. Another concern arises due to progressive accumulation of leucomalachite green formed via biotransformation of MG in various tissues; it can enter mammalian cells through the food chain and poses high toxicity. Diverse treatment strategies such as oxidation, filtration, photo degradation and photo catalytic degradation are available for MG removal. These methods do not degrade the pollutants or contaminants effectively and are time consuming as well as costly. Compared to these techniques, adsorption has now been proved to be a highly efficient and cost-effective method to remove this toxic dye from wastewater before it is released into the aquatic environment. This study has attempted a compilation of various adsorption matrices and their feasibility for MG removal.