Determination of antifungal efficacy and phytotoxicity of a unique silica coated porous zinc oxide nanocomposite medium for slow-release agrochemicals.

AIMS: In this study the antifungal efficacy and phytotoxicity of silica coated porous zinc oxide nanoparticle (SZNP) was analyzed as this nanocomposite was observed to be a suitable platform for slow release fungicides and has the promise to bring down the dosage of other agrochemicals as well. METHODS AND RESULTS: Loading and release kinetics of tricyclazole, a potent fungicide was analyzed by measuring surface area (SBET) using Brunauer-Emmett-Teller (BET) isotherm and LC-MS/MS respectively. The antifungal efficacy of ZnO nanoparticle (ZNP) and SZNP was investigated on two phytopathogenic fungi (Alternaria solani and Aspergillus niger). The morphological changes to the fungal structure due to ZNP and SZNP treatment were studied by field emission-scanning electron microscopy (FESEM). Nanoparticle mediated elevation of reactive oxygen species in fungal samples was detected by analyzing the level of superoxide dismutase, catalase, thiol content, lipid peroxidation and by 2,7-dichlorofluorescin diacetate (DCFH-DA) assay. The phytotoxicity of these two nanostructures was assessed in rice plants by measuring primary plant growth parameters. Further, the translocation of the nanocomposite in the same plant model system was examined by checking the presence of Fluorescein isothiocyanate (FITC) tagged SZNP within the plant tissue. CONCLUSIONS: ZNP had superior antifungal efficacy than SZNP and caused generation of more reactive oxygen species (ROS) in the fungal samples. Even then SZNP was preferred as an agrochemical delivery vehicle because unlike ZNP alone it was not toxic to plant system. Moreover, as silica in nano form is entomotoxic in nature and nano ZnO has antifungal property, both the cargo (agrochemical) and the carrier system (silica coated porous nano zinc oxide) will have a synergistic effect in crop protection.

Emerging stock market reactions to shocks during various crisis periods.

This study investigates granger causal linkages among six Asian emerging stock markets and the US market over the period 2002-2020, taking into account several crisis periods. The pairwise Granger causality tests for investigating the short-run causality show significant bi- and uni-directional causal relationships in those markets and evidence that they have become more internationally integrated after every crisis period. An exception is Bangladesh with almost no significant short-term causal linkages with other markets. For understanding, how the financial linkages amplify volatility spillover effects, we apply the GARCH-M model and find that volatility and return spillovers act very inversely over time. However, market interface is weak before the crisis periods and becomes very strong during the financial crisis and US-China economic policy uncertainty periods. The US market plays a dominant role during the financial crisis and COVID-19 periods. Further analysis using the VAR model shows that a large proportion of the forecast variance of the Asian emerging stock markets is affected by the S&P 500 and that market shock starts to rise notably from the 1 to 10 period. The overall findings could provide important policy implications in the six countries under study regarding hedging, trading strategies, and financial market regulation.

Application of Core/Shell Nanoparticles in Smart Farming: A Paradigm Shift for Making the Agriculture Sector More Sustainable.

Modern agriculture has entered an era of technological plateau where intervention of smarter technology like nanotechnology is imminently required for making this sector economically and environmentally sustainable. Throughout the world, researchers are trying to exploit the novel properties of several nanomaterials to make agricultural practices more efficient. Core/shell nanoparticles (CSNs) have attracted much attention because of their multiple attractive novel features like high catalytic, optical, and electronic properties for which they are being widely used in sensing, imaging, and medical applications. Though it also has the promise to solve a number of issues related to agriculture, its full potential still remains mostly unexplored. This review provides a panoramic view on application of CSNs in solving several problems related to crop production and precision farming practices where the wastage of resources can be minimized. This review also summarizes different classes of CSNs and their synthesis techniques. It emphasizes and analyzes the probable potential applications of CSNs in the field of crop improvement and crop protection, detection of plant diseases and agrochemical residues, and augmentation of chloroplast mediated photosynthesis. In a nutshell, there is enormous scope to formulate and design CSN-based smart tools for applications in agriculture, making this sector more sustainable.

Recent trends in nanomaterials applications in environmental monitoring and remediation.

Environmental pollution is one of the greatest problems that the world is facing today, and it is increasing with every passing year and causing grave and irreparable damage to the earth. Nanomaterials, because of their novel physical and chemical characteristics, have great promise to combat environment pollution. Nanotechnology is being used to devise pollution sensor. A variety of materials in their nano form like iron, titanium dioxide, silica, zinc oxide, carbon nanotube, dendrimers, polymers, etc. are increasingly being used to make the air clean, to purify water, and to decontaminate soil. Nanotechnology is also being used to make renewable energy cheaper and more efficient. The use of nanotechnology in agriculture sector will reduce the indiscriminate use of agrochemicals and thus will reduce the load of chemical pollutant. While remediating environment pollution with nanomaterials, it should also be monitored that these materials do not contribute further degradation of the environment. This review will focus broadly on the applications of nanotechnology in the sustainable development with particular emphasis on renewable energy, air-, water-, and soil-remediation. Besides, the review highlights the recent developments in various types of nanomaterials and nanodevices oriented toward pollution monitoring and remediation.

Prevalence and Risk Factors for Oral Potentially Malignant Disorders in Indian Population.

Objective. To assess the prevalence of oral potentially malignant disorders and to determine the potential risk factors for its development in Indian population. Materials and Methods. This cross-sectional study was carried out on 1241 individuals in Indore, Madhya Pradesh. A questionnaire was designed to record information about sociodemographic characteristics, oral hygiene practices, dietary habits, and risk factors for oral potentially malignant disorders. Oral mucosal lesions were examined by a skilled person. Results. The overall prevalence of oral potentially malignant disorders was found to be 13.7% with oral submucous fibrosis (8.06%) found to be more common and erythroplakia (0.24%) found to be least prevalent. Results of Logistic Regression analysis showed that males (OR = 2.09, P value < 0.0001) who were ever consumers of tobacco (OR = 2.06, P value = 0.030) and areca nut chewing (OR = 2.64, P value = 0.004) were more likely to develop oral potentially malignant disorders compared to never consumers. Diabetic (OR = 2.21, P value = 0.014) and underweight individuals (OR = 2.23, P value = 0.007) were more likely to suffer from oral potentially malignant disorders. Conclusion. The study reinforces the association of tobacco and areca nut consumption with oral potentially malignant disorders. An association of oral potentially malignant disorders with diabetes and BMI was confirmed by this study.

Occupational Hepatitis B Exposure: A Peek into Indian Dental Students' Knowledge, Opinion, and Preventive Practices.

Objective. To determine the level of knowledge, opinions, and preventive practices followed by dental students against Hepatitis B. The study also explored if any correlation existed between knowledge, opinion, and preventive practices score. Materials and Methods. A cross-sectional study was conducted in a dental teaching institution. The subjects comprised 216 dental students. The study was conducted using a pretested, self-administered questionnaire. The questionnaire was prepared to assess knowledge, opinion, and preventive practices against Hepatitis B. Kruskal-Wallis and Kendall Tau test were performed. Results. The study found that only 44.4% of the students were vaccinated with Hepatitis B vaccine. 59.3% of the students reported washing their hands after contact with patient's body fluids. 63.9% used personal protective measures like facemask, aprons, head cap, eye shields, and so forth, while treating patients. Median knowledge, opinion, and practice scores were found to be 5.00, 3.00, and 3.00, respectively. Significant correlation was obtained between knowledge and preventive practices score (r = 0.385, p value <0.0001). Conclusion. Effective measures need to be taken to improve preventive practices of the students to prevent them from risk of Hepatitis transmission. Mandatory vaccination against Hepatitis B needs to be implemented.

Chitosan, Carbon Quantum Dot, and Silica Nanoparticle Mediated dsRNA Delivery for Gene Silencing in Aedes aegypti: A Comparative Analysis.

In spite of devastating impact of mosquito borne pathogens on humans, widespread resistance to chemical insecticides and environmental concerns from residual toxicity limit mosquito control strategies. We tested three nanoparticles, chitosan, carbon quantum dot (CQD), and silica complexed with dsRNA, to target two mosquito genes (SNF7 and SRC) for controlling Aedes aegypti larvae. Relative mRNA levels were quantified using qRT-PCR to evaluate knockdown efficiency in nanoparticle-dsRNA treated larvae. The knockdown efficiency of target genes correlated with dsRNA mediated larval mortality. Among the three nanoparticles tested, CQD was the most efficient carrier for dsRNA retention, delivery, and thereby causing gene silencing and mortality in Ae. aegypti.

Prevalence and risk factors for non-carious cervical lesions in children attending special needs schools in India.

We assessed the prevalence and risk factors for development of non-carious cervical lesions (NCCLs) in children attending special needs schools in India. The participants were 395 children aged 12-15 years with disabilities in learning, communication, physical function, and/or development. A questionnaire was designed in order to collect information on sociodemographic characteristics, oral hygiene practices, dietary habits, and risk factors for NCCLs. The chi-square test, bivariate analysis, and logistic regression analysis were used to analyze the data. Presence of NCCLs was associated with use of toothpowder or other materials for teeth cleaning, use of harder toothbrushes, use of a horizontal scrub technique for toothbrushing, consumption of a vegetarian diet, and greater consumption of lemon. The overall prevalence of NCCLs was 22.7%. Most lesions involved minimal loss of contour or defects <1 mm in depth. The prevalence of non-carious cervical lesions was slightly higher than the global average. Effective policies should be developed for oral health care among children attending special needs schools.

Microwave synthesis of ZnO@mSiO2 for detailed antifungal mode of action study: understanding the insights into oxidative stress.

A simple chemical method has been devised for deliberate incorporation of zinc oxide nanoparticles (ZNPs) within mesoporous nanosilica (mSiO2) matrix to yield zinc oxide nanoparticles embedded in mesoporous nanosilica (ZnO@mSiO2). ZnO@mSiO2 inhibited the growth of four strains of fungi in a dose dependant manner. A series of biochemical assays revealed generation of oxidative stress from ZnO@mSiO2 for such biocidal response. We proposed transient superoxide and its subsequent conversion to H2O2 played a pivotal role behind such biocidal response as revealed from our systematic evaluation. This resulted morphological alteration of fungi through increase in number of facets, in correlation we found up-regulation in oxidative stress related genes. Bioavailability within the fungal sample was confirmed from microscopic, spectroscopic, biophysical techniques. Protein carbonylation of fungal species was the chemical outcome of such above mentioned stress and quantified by high performance liquid chromatography (HPLC) via subsequent hydrazone derivatization. Several in vitro and in vivo evaluations revealed the biocompatibility of ZnO@mSiO2. Altogether this report claims a new biocidal agent with a detailed mode of action focusing on the origin and quantification of oxidative stress through biophysical and biochemical techniques for the first time for real time applications.

Gingival squamous cell carcinoma presenting as periodontal lesion in the mandibular posterior region.

Gingival squamous cell carcinoma (GSCC) is a relatively rare malignant neoplasm of the oral cavity. It represents less than 10% of diagnosed intraoral carcinoma. Because of its close proximity to the teeth and periodontium, the tumour can mimic tooth-related benign inflammatory conditions. This case report describes a patient diagnosed with GSCC presenting as localised periodontitis.

Dental caries experience in high risk soft drinks factory workers of South India: a comparative study.

BACKGROUND: The consumption of soft-drinks has been associated with dental caries development. OBJECTIVE: The aim was to evaluate dental caries experience amongst the workers working in soft-drink industries located in South India and compare it with other factory workers. To evaluate the validity of specific caries index (SCI), which is newer index for caries diagnosis. MATERIALS AND METHODS: This was a cross-sectional study carried out among 420 workers (210 in soft-drinks factory and 210 in other factories), in the age group of 20-45 years of Udupi district, Karnataka, India. Index used for clinical examination was decayed, missing, filled surfaces (DMFS) index and SCI. RESULTS: The mean and standard deviation (SD) of decayed surface (5.8 ± 1.8), missing surface (4.3 ± 2) and filled surface (1.94 ± 1.95) and total DMFS score (12.11 ± 3.8) in soft-drinks factory workers were found to be significantly higher than the other factory workers. The total SCI score (mean and SD) was found to be significantly higher in soft-drinks factory workers (5.83 ± 1.80) compared with other factory workers (4.56 ± 1.45). There was a high correlation obtained between SCI score and DMFS score. The regression equation given by DMFS = 1.178 + 1.866 (SCI scores). CONCLUSION: The caries experience was higher in workers working in soft-drinks factory and this study also showed that specific caries index can be used as a valid index for assessing dental caries experience.

Iatrogenic subcutaneous emphysema of endodontic origin - case report with literature review.

Surgical emphysema is well known and many case reports have been published on this. Many authors have reported this as a complication post dentoalveolar treatment. Diffusion of air into facial planes and periorbital area during endodontic procedures has been rarely reported. The use of three way air syringe and forceful irrigation of root canal can lead to surgical emphysema of subcutaneous tissue planes in and around the teeth which are involved. This case report highlights one such complication seen during endodontic treatment, discusses aetiology, complications and conservative management of this dental office emergency.

Relationship of inter-condylar distance with inter-dental distance of maxillary arch and occlusal vertical dimension: a clinical anthropometric study.

AIM: To find out the anthropometric relationship of Inter-condylar distance to Inter-canine and Inter-molar distance of maxillary arch and occlusal vertical dimension in dentate individuals of South Indian population. MATERIALS AND METHODS: A total number of 120 dentate individuals were randomly equally divided into Group A and Group B. According to the face form, each Group was again subdivided into four subgroups. Subgroup A1 and B1 contained Square face form, Subgroup A2 and B2 Tapered, Subgroup A3 and B3 Square tapered and Subgroup A4 and B4 Ovoid face form. The ratio of ICD to U3, U6 and OVD of Group A individuals were applied to the Group B individuals with similar face forms and the clinical significance of the ratios were evaluated. RESULTS: No significant difference (p-value=0.841) was observed in the ratio of U6 to ICD (U6/ICD) in all the face forms. A significant difference (p-value = 0.010) in the mean value was observed when the ratio of OVD to ICD (OVD/ICD) was compared between the squared tapered face form of Group A (0.60 ± 0.01) and Group B (0.06±0.03). A significant difference (p value = 0.007) was observed between the measured (62.47 ±2.77) and calculated (64.99±2.61) values of OVD in square taper face form. CONCLUSION: In south Indian population, ICD can be used as a reliable guide line to determine the bucco-palatal position of maxillary first molar irrespective of the face forms.

Prevalence and risk factors for dental erosion among 11- to 14-year-old school children in South India.

This cross-sectional survey was conducted to assess the prevalence and severity of dental erosion and to determine the potential risk factors for dental erosion among 11- to 14-year-old school children in South India. The total sample size for the study was 605, of which 303 school children were from private schools and 302 from public schools. A questionnaire was designed to record information about socio-demographic characteristics, oral hygiene practices, dietary habits and risk factors for dental erosion. Chi square test, bivariate analysis and Logistic regression analysis were performed to analyse the data. The children who consumed lemon several times a day (OR = 13.41, P < 0.001), and those who preferred carbonated drinks (OR = 2.80, P = 0.007) had a higher tendency to develop dental erosion. The overall prevalence of dental erosion was found to be low (8.9%). Erosion was found to be greater in posterior teeth (65.6%) than anterior teeth (34.4%). Loss of enamel only with loss of surface contour was observed in most (94.8%) of the cases. The prevalence of dental erosion was found to be low in school children. Private school children were affected more by dental erosion. Frequency of lemon consumption and consumption of carbonated drinks were identified as risk factors.

Nanoparticle-induced morphological transition of Bombyx mori nucleopolyhedrovirus: a novel method to treat silkworm grasserie disease.

Grasserie, a polyorganotrophic disease caused by Bombyx mori nucleopolyhedrovirus (BmNPV), accounts for lethal infection to fifth instar silkworm larvae. It was found that nanoparticle (NP)-induced morphological transformation of BmNPV polyhedra could reduce the infectivity of BmNPV both in cell line and in silkworm larvae. Initially, 11 NPs were screened for evaluation of their nature of interaction with polyhedra surface through scanning electron microscopy. Amongst these NPs, lipophilically coated silica nanoparticle (SNPL), alumina nanoparticles in the hexagonal close-packed α structure and aspartate capped gold nanoparticle transformed polyhedra were tested for their infectivity in B. mori cell line using cytopathic effect and plaque reduction assay. SNPL was evaluated for its bio-efficacy in fifth instar silkworm larvae. The study of polyhedra morphology as a function of NP concentration showed severe 'roughening' of the polyhedra with replacement of the regular facets by a large number of irregular ones by SNPL, and this caused transition of highly infectious polyhedra into a nearly spherical, non-infectious structure. A moderate polyhedra roughening was observed for alumina NPs, and no roughening was noticed for gold NPs. The morphological changes could be correlated with reduction of virus-induced cytopathic effect and plaque formation, and increased survival rate of SNPL transformed polyhedra infected silkworm larvae to 70.09±6.61% after 96 h. In this group, 61.04±8.03% larvae formed normal cocoons from which moths eclosed, laid eggs and larvae emerged. This study could lead to open up newer pathways for designing nano pharmaceuticals to combat other viral diseases.

Biochemical-, biophysical-, and microarray-based antifungal evaluation of the buffer-mediated synthesized nano zinc oxide: an in vivo and in vitro toxicity study.

Here we describe a simple, novel method of zinc oxide nanoparticle (ZNP) synthesis and physicochemical characterization. The dose-dependent antifungal effect of ZNPs, compared to that of micronized zinc oxide (MZnO), was studied on two pathogenic fungi: Aspergillus niger and Fusarium oxysporum. Superoxide dismutase (SOD) activity, ascorbate peroxidase activity, catalase activity, glutathione reductase (GR) activity, thiol content, lipid peroxidation, and proline content in ZNP-treated fungal samples were found to be elevated in comparison to the control, which strongly suggested that the antifungal effect of ZNPs was due to the generation of reactive oxygen species (ROS). Protein carbonylation, another marker of oxidative stress, was also evaluated by the dinitrophenyl hydrazine (DNPH) binding assay and Fourier transform infrared (FTIR) spectral analysis followed by Western blot and microarray analysis of fungal samples to confirm ROS generation by ZNPs. Micrographic studies for the morphological analysis of fungal samples (ZNP-treated and a control) exhibited an alteration in fungal morphology. The bioavailability of ZNPs on fungal cell was confirmed by energy-dispersive X-ray (EDX) analysis followed by high-resolution transmission electron microscopy (HR-TEM) and confocal microscopic analysis of the fungal samples. In vivo acute oral toxicity, acetylcholine esterase activity, and a fertility study using a mice model were also investigated for ZNPs. The long-term toxicity of ZNPs through intravenous injection was evaluated and compared to that of MZnO. The in vitro comparative toxicity of ZNPs and MZnO was evaluated on MRC-5 cells with the help of water-soluble tetrazolium (WST-1) and lactate dehydrogenase (LDH) assays. These results suggested that ZNPs could be used as an effective fungicide in modern medical and agricultural sciences.

Comparative analysis of stability and toxicity profile of three differently capped gold nanoparticles for biomedical usage.

Nowadays gold nanoparticle (GNP) is increasingly being used in drug delivery and diagnostics. Here we have reported a comparative analysis of detailed stability and toxicity (in vitro and in vivo) profile of three water soluble spherical GNPs, having nearly similar size, but the surfaces of which were modified with three different capping materials aspartic acid (GNPA), trisodium citrate dihydrate (GNPC) or bovine serum albumin (GNPB). Spectral analyses on the stability of these GNPs revealed that depending on the nature of capping agents, GNPs behave differently at different environmental modalities like wide range of pH, high salt concentrations, or in solutions and buffers of biological usage. GNPB was found to be extremely stable, where capped protein molecule successfully maintained its secondary structure and helicity on the nanoparticle, whereas colloidal stability of GNPA was most susceptible to altered conditions. In vitro cytotoxicity of these nanoparticle formulations in vitro were determined by water soluble tetrazolium and lactate dehydrogenase assay in human fibroblast cell line (MRC-5) and acute oral toxicity was performed in murine model system. All the GNPs were non-toxic to MRC-5 cells. GNPC had slight hepatotoxic and nephrotoxic responses. Hepatotoxicity was also evident for GNPA treatment. Present study established that there is a correlation between capping material and stability together with toxicity of nanoparticles. GNPB was found to be most biocompatible among the three GNPs tested.

Nature-inspired novel drug design paradigm using nanosilver: efficacy on multi-drug-resistant clinical isolates of tuberculosis.

Despite discovery of the pathogen more than 100 years ago, tuberculosis (TB) continues to be a major killer disease worldwide. Currently a third of world population is infected and multiple-drug-resistant (mdr) TB registers maximum mortality by a single pathogen. Nanomedicine provides enormous opportunity for developing novel drugs. We have recently demonstrated surface-modified-lipophilic-nanosilica as drug to combat malaria and 100% lethal virus, BmNPV. Nanosilver possesses inherent antibacterial properties, but toxicity is a major concern. We hypothesized that capping with nature-inspired biomolecules, bovine serum albumin (BSA) and Poly-n-vinyl-pyrrolidone (PVP) used as blood volume extender, might insure biosafety. BSA-nano-Ag was found to be more stable than PVP-nano-Ag at physiological pH. In this first ever study on clinical isolates collected from TB endemic areas, we report, BSA-nano-Ag act as potent anti-TB drug. Further study with (human serum albumin)-nano-Ag and core-shell-nano-Ag could increase the biocompatibility of oral TB drug formulations without compromising on the efficacy of the drug.

Comparison of different silicas of natural origin as possible insecticides.

Many insect-pests have developed resistances to pesticides. Therefore, there is always a need for new plant protection substances. For example the physically active insecticide diatomaceous earth (DE) gained much attention as an alternative insecticide in stored products. DE is a naturally occurring silica, which acts by destroying the insect's cuticle by absorbing the protective wax layer. This results in body water loss and ultimately the insect's death by desiccation. The silica-based materials tested were the commercial DE product Fossil Shield 90.0s, Advasan, and a formulation newly developed by the Urban Horticultural Department at Humboldt University, called Al-06. The trials were performed in small covered plastic boxes. Test substances were either dusted onto the surface of the boxes (E. vigintioctopunctata, S. litura) or mixed into rice medium (S. oryzae). The mortality was observed after 1, 2, 4, 7, 14, and 28 days. Untreated insects served as control. The first test series showed that some AL-06-formulations and FS90.0s were very effective against adults of S. oryzae and S. litura and larvae of E. vigintioctopunctata. For adult Epilachna beetles, we could not detect any differences between the treatments. The highest mortality rate in S. oryzae trials occurred with FS90.0s (100%) after 21 days. The same efficiency was achieved after 2 days with some AL-06 formulations against S. litura and E. vigintioctopunctata. The results of this study indicate that silica dusts can effectively control insect pests from different orders. At higher dosages, all materials resulted in higher insect mortality rates. It was also found that some substances did not perform well under higher rel. humidity; therefore, the conclusion was drawn that hydrophilic substances saturate with water from the surrounding air and lose their insecticidal efficacy. Earlier studies have proven that particles with a larger surface area are more effective than particles with smaller surfaces. As a result, the most effective substances in the field trials were the ones containing the small particles, since there is a larger surface area available to interact with the insects' cuticles. Further studies will be conducted to analyse the relevance of water saturation of substances in order to examine their effectiveness under greenhouse conditions. Greenhouse experiments are generally considered to study practicability of silica dusts in horticulture. Perhaps the silica dusts will show phytotoxic side effects.