Biosynthesis of silver nanoparticle from flower extract of Dillenia indica and its efficacy as antibacterial and antioxidant.

Dillenia indica is a medicinal tree of the Dilleniaceae and its flower extract was used for the synthesis of silver nanoparticle (AgNPs). The optimal conditions for AgNPs synthesis were as such: 2 mM AgNO3, pH 4.5 and 48-h reaction time. The characteristic band of AgNPs was observed at the wavelength of 435 nm by UV-visible spectroscopic study. Fourier-transform infrared (FTIR) analysis depicted the involvement of several functional groups of plant extracts in the synthesis of AgNPs. Nanoparticles were mostly spherical shaped and uniformly distributed, when observation was made by Transmission electron microscopy (TEM). Energy Dispersive X-Ray (EDX) showed absorption peak approximately at 3 keV thus confirmed the presence of silver metal in AgNP. X-ray diffraction (XRD) investigation and selected area electron diffraction (SAED) patterns showed the crystalline nature of the AgNPs. Dynamic light scattering (DLS) analysis exhibited average size of the nanoparticles as 50.17 nm with a polydispersity index (PDI) value of 0.298. The zeta potential of nanoparticles was observed as -24.9 mV. To assess antibacterial activity, both AgNPs alone or its combination with the antibiotic were tried against six pathogenic bacteria. The combination of AgNPs with antibiotic was maximum effective against Shigella boydii (16.07 ± 0.35) and Klebsiella pneumoniae (15.03 ± 0.20). AgNPs alone showed maximum inhibition for both Gram-positive bacteria: methicillin-resistant Staphylococcus aureus (19.97 ± 0.20 mm) and Enterococcus faecium (19.80 ± 0.15 mm). Maximum inhibition of Enterobactor cloacae and Pseudomonas aeruginosa was observed by antibiotic taken alone. Evaluation through 2,2-diphenyl-1-picrylhydrazyl (DPPH) and DNA nicking assays demonstrated the antioxidant capabilities of the nanoparticles.

Meta-Analysis of Cytotoxicity Studies Using Machine Learning Models on Physical Properties of Plant Extract-Derived Silver Nanoparticles.

Silver nanoparticles (Ag-NPs) demonstrate unique properties and their use is exponentially increasing in various applications. The potential impact of Ag-NPs on human health is debatable in terms of toxicity. The present study deals with MTT(3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium-bromide) assay on Ag-NPs. We measured the cell activity resulting from molecules' mitochondrial cleavage through a spectrophotometer. The machine learning models Decision Tree (DT) and Random Forest (RF) were utilized to comprehend the relationship between the physical parameters of NPs and their cytotoxicity. The input features used for the machine learning were reducing agent, types of cell lines, exposure time, particle size, hydrodynamic diameter, zeta potential, wavelength, concentration, and cell viability. These parameters were extracted from the literature, segregated, and developed into a dataset in terms of cell viability and concentration of NPs. DT helped in classifying the parameters by applying threshold conditions. The same conditions were applied to RF to extort the predictions. K-means clustering was used on the dataset for comparison. The performance of the models was evaluated through regression metrics, viz. root mean square error (RMSE) and R2. The obtained high value of R2 and low value of RMSE denote an accurate prediction that could best fit the dataset. DT performed better than RF in predicting the toxicity parameter. We suggest using algorithms for optimizing and designing the synthesis of Ag-NPs in extended applications such as drug delivery and cancer treatments.

An In Vitro and In Vivo Study of the Efficacy and Toxicity of Plant-Extract-Derived Silver Nanoparticles.

Silver nanoparticles (AgNPs) display unique plasmonic and antimicrobial properties, enabling them to be helpful in various industrial and consumer products. However, previous studies showed that the commercially acquired silver nanoparticles exhibit toxicity even in small doses. Hence, it was imperative to determine suitable synthesis techniques that are the most economical and least toxic to the environment and biological entities. Silver nanoparticles were synthesized using plant extracts and their physico-chemical properties were studied. A time-dependent in vitro study using HEK-293 cells and a dose-dependent in vivo study using a Drosophila model helped us to determine the correct synthesis routes. Through biological analyses, we found that silver nanoparticles' cytotoxicity and wound-healing capacity depended on size, shape, and colloidal stability. Interestingly, we observed that out of all the synthesized AgNPs, the ones derived from the turmeric extract displayed excellent wound-healing capacity in the in vitro study. Furthermore, the same NPs exhibited the least toxic effects in an in vivo study of ingestion of these NPs enriched food in Drosophila, which showed no climbing disability in flies, even at a very high dose (250 mg/L) for 10 days. We propose that stabilizing agents played a superior role in establishing the bio-interaction of nanoparticles. Our study reported here verified that turmeric-extract-derived AgNPs displayed biocompatibility while exhibiting the least cytotoxicity.

Efficacy and Safety of Single Oral Dosing of Secnidazole for Trichomoniasis in Women: Results of a Phase 3, Randomized, Double-Blind, Placebo-Controlled, Delayed-Treatment Study.

BACKGROUND: Trichomonas vaginalis is the most prevalent nonviral sexually transmitted infection. We evaluated the efficacy and safety of secnidazole vs placebo in women with trichomoniasis. METHODS: Women with trichomoniasis, confirmed by a positive T. vaginalis culture, were randomized to single-dose oral secnidazole 2 g or placebo. The primary endpoint was microbiological test of cure (TOC) by culture 6-12 days after dosing. At the TOC visit, participants were given the opposite treatment. They were followed for resolution of infection afterward and offered treatment at subsequent visits, if needed. Fifty patients per group (N = 100) provided approximately 95% power to detect a statistically significant difference between treatment groups. RESULTS: Between April 2019 and March 2020, 147 women enrolled at 10 sites in the United States. The modified intention-to-treat (mITT) population included 131 randomized patients (secnidazole, n = 64; placebo, n = 67). Cure rates were significantly higher in the secnidazole vs placebo group for the mITT population (92.2% [95% confidence interval {CI}: 82.7%-97.4%] vs 1.5% [95% CI: .0%-8.0%]) and for the per-protocol population (94.9% [95% CI: 85.9%-98.9%] vs 1.7% [95% CI: .0%-8.9%]). Cure rates were 100% (4/4) in women with human immunodeficiency virus (HIV) and 95.2% (20/21) in women with bacterial vaginosis (BV). Secnidazole was generally well tolerated. The most frequently reported treatment-emergent adverse events (TEAEs) were vulvovaginal candidiasis and nausea (each 2.7%). No serious TEAEs were observed. CONCLUSIONS: A single oral 2 g dose of secnidazole was associated with significantly higher microbiological cure rates vs placebo, supporting a role for secnidazole in treating women with trichomoniasis, including those with HIV and/or BV. CLINICAL TRIALS REGISTRATION: NCT03935217.

Detection of Fusarium wilt pathogens of Psidium guajava L. in soil using culture independent PCR (ciPCR).

Traditional culturing methods take a long time for identification of pathogenic isolates. A protocol has been developed for the detection of Fusarium from soil samples in the early stage of infection. Seventeen soil samples from different locations were collected before the onset of rains to find out the presence of Fusarium spp. population present in the soil of guava orchards and to correlate its presence with incidence of wilt. A PCR based method was developed for the molecular characterization of Fusarium using Fusarium spp. specific primer. DNA extracted by this method was free from protein and other contaminations and the yield was sufficient for PCR amplification. The primer developed in this study was amplifying ∼230 bp in all infected samples while not in healthy soil. The specificity and sensitivity of primer were tested on several Fusarium spp. and found that this primer was amplifying 10(-6) dilution of the fungal DNA. The present study facilitates the rapid detection of Fusarium spp. from infected soil samples of guava collected from different agroclimatic regions in India. A rapid detection method for pathogens and a diagnostic assay for disease would facilitate an early detection of pathogen and lead to more effective control strategies.

Molecular detection and genotyping of Fusarium oxysporum f. sp. psidii isolates from different agro-ecological regions of India.

Twenty one isolates of Fusarium oxysporum f. sp. psidii (Fop), causing a vascular wilt in guava (Psidium guajava L.), were collected from different agro-ecological regions of India. The pathogenicity test was performed in guava seedlings, where the Fop isolates were found to be highly pathogenic. All 21 isolates were confirmed as F. oxysporum f. sp. psidii by a newly developed, species-specific primer against the conserved regions of 28S rDNA and the intergenic spacer region. RAPD and PCR-RFLP were used for genotyping the isolates to determine their genetic relationships. Fifteen RAPD primers were tested, of which five primers produced prominent, polymorphic, and reproducible bands. RAPD yielded an average of 6.5 polymorphic bands per primer, with the amplified DNA fragments ranging from 200-2,000 bp in size. A dendrogram constructed from these data indicated a 22-74% level of homology. In RFLP analysis, two major bands (350 and 220 bp) were commonly present in all isolates of F. oxysporum. These findings provide new insight for rapid, specific, and sensitive disease diagnosis. However, genotyping could be useful in strain-level discrimination of isolates from different agro-ecological regions of India.

Magnetic studies of multiferroic Bi(1-x)Sm(x)FeO(3) ceramics synthesized by mechanical activation assisted processes.

Bi(1-x)Sm(x)FeO(3) (x = 0.0-0.2) ceramic samples were prepared by mechanical activation assisted solid-state-reaction synthesis. A stoichiometric mixture of Bi(2)O(3), Sm(2)O(3), and Fe(2)O(3) powders was mechanically milled and this was followed by heat treatment at 700 °C for 1 h. Room temperature x-ray diffraction patterns confirmed the formation of perovskite structured Bi(1-x)Sm(x)FeO(3) phase. Vibrating sample magnetometry measurements showed that to a certain extent, Sm doping of BiFeO(3) leads to increased magnetization and a sharp magnetic transition at ∼380 °C. Mössbauer spectroscopy confirmed the presence of single-phase material for the doped compositions whereas electron paramagnetic resonance analysis showed the effect of doping on the variation in the degree of canting in the samples. At doping levels of 10 at.% Sm, the improvement in the magnetic behaviour appears to arise from a combination of the propensity of the samples to form pure phase material, partial destruction of spin cycloids, increased canting of spins and interaction between magnetic ions.

Properties of nanocrystalline Fe75Si15M10 (M-Cr and Al) powders prepared by mechanical alloying.

We report the structural and magnetic properties of the nanocrystalline Fe75Si15M10 (M-Al and Cr) powders prepared by mechanical alloying. The milling process produced a non-equilibrium solid solutions of bcc alpha-Fe(Si,Cr) and alpha-Fe(Si,Al). The average dislocation density increases and the average crystallite size decreases with increasing milling time. Magnetic property studies show that the coercivity of the sample increases and magnetization of the sample decreases with increasing milling time. The evolution of a non-equilibrium solid solution and the resulting magnetic properties of nanocrystalline powders are explained on the basis of Neel theory and modified random anisotropy model proposed by Shen et al.

Anomalous structural and magnetic behaviour of Fe-25 at.% Ni alloy due to mechanical strain.

Mechanical strain was induced in Fe-25 at.% Ni alloy by filing the ingots into powder form. The phase transformations induced by the deformation thus caused and subsequent annealing were studied by x-ray diffraction, magnetization measurement and Mössbauer spectroscopy. It is concluded that around one-third of the Fe atoms became segregated from the Fe-Ni alloy due to filing. Annealing of the filed powder led to recombination of this segregated Fe to form an apparently body-centred cubic (bcc) phase of Fe-Ni which shows little magnetic ordering at room temperature in magnetization measurements or in Mössbauer spectroscopy. The single-line Mössbauer spectrum of this phase splits into a six-line pattern below 100 K.