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Laser Beam Welding (LBW) is extensively being utilized in manufacturing processes to join dissimilar metals and alloy steels because its special advantages of controlled heating, Low Heat Affected Zone (HAZ) and smaller weld bead formation. However, it is viewed as a strange strategy with applications normally and constrained to welding of thick plates of metals. With a new generation of high power lasers, there has been a renewed interest in thick section LBW (also known as Keyhole Laser Welding (KLW)). KLW makes the process a possibility for industrial applications dealing with thick metals for welding in power plants, pipelines, offshore structures, shipbuilding. The advantages provided by such LBW, is suitable for joining at high process speed, low heat input, and to achieve high productivity, leading to significantly reduction in process costs. LBW of dissimilar metals such as alloy steel and stainless steel is still a challenging task, particularly due to the formation of martensitic formation in HAZ, brittle phases in the weld and solidification cracking in the fusion zone. Such issues can significantly deteriorate strength of the welded joint. Therefore, the aim of the present work is to examine the basic phenomena that happen inside the different weld zones and their impact on weld quality in the wake of LBW joints. Taguchi L25 is chosen and experiments are conducted with LBW considering 2 mm thick dissimilar metals, i.e. AISI 4130 and AISI 309 stainless steel by varying Laser Power, Welding Speed, Beam Angle, Focal Point Position and Focal Length. The experimental output results that are measured for the mechanical properties like Ultimate Tensile Strength and Impact Strength. The Analysis of Variance (ANOVA) is carried out to obtain the influence of the process parameters and statistical evolution of the results. Firefly optimization algorithm is used to determine the optimal combination of the process parameters of the LBW

The capsids of viruses have a high degree of symmetry. Therefore, virus nanoparticles (VNPs) can be programmed to display many imaging agents precisely. Plant VNPs are biocompatible, biodegradable and non-infectious to mammals. We have carried out bioconjugation of sesbania mosaic virus (SeMV), a well characterized plant virus, with fluorophores using reactive lysine-N-hydroxysuccinimide ester and cysteine-maleimide chemistries. Monitoring of cellular internalization of labelled SeMV nanoparticles (NPs) by confocal microscopy and flow cytometry showed that the particles have a natural preference for entry into MDA-MB-231 (breast cancer) cells, although they could also enter various other cell lines. The fluorescence of SeMV NPs labelled via the cysteines with Cy5.5 dye was found to be more stable and was detectable with greater sensitivity than that of particles labelled via the lysines with Alexa Fluor. Live-cell imaging using SeMV internally labelled with Cy5.5 showed that it could bind to MDA-MB-231 cells in less than 5 minutes and enter the cells within 15 minutes. The particles undergo endolysosomal degradation by 6 h as evidenced by their co-localization with LAMP-1. Far-western blot analysis with a HeLa cell membrane protein fraction showed that SeMV interacts with 54-, 35- and 33-kDa proteins, which were identified by mass spectrometry as vimentin, voltage-dependent anion-selective channel protein (VDAC1), and annexin A2 isoform 2 (ANXA2), respectively, suggesting that the particles may bind and enter the cell through these proteins. The results presented here demonstrate that the SeMV NPs provide a new platform technology that could be used to develop in vivo imaging and targeted drug delivery agents for cancer diagnosis and therapy.

Viral nanobiotechnology is an emerging and fascinating field, dealing with the use of virus-based nanoparticles as templates and/or building blocks to display novel molecular moieties with specific properties for a wide range of applications in biology, medicine, and materials science. Viral nanoparticles (VNPs) and virus like particles (VLPs) are naturally occurring highly organized, programmable nanoassemblies that provide excellent platforms for nanoscale fabrication due to their unique physical and chemical properties. Plant virus-based nanoparticles (PVNs-VNPs and VLPs derived from plant viruses) have been explored for several years either to express subunit vaccines or as epitope presentation systems. In the recent times, these PVNs are attracting the attention of researchers and clinicians due to their several attractive features such as size range (nanometer), relative structural stability, high degree of symmetry, polyvalency, monodispersity, noninfectious and nonhazardous nature when injected to mammals, low cost of production, and biocompatibility. VNPs and VLPs can readily be engineered chemically and genetically to carry targeting ligands, therapeutic antibodies, and imaging agents and drugs on their exterior and interior surfaces. This review aims to summarize important plant virus-based nanomaterials (icosahedral and helical shaped) that have been developed for imaging, drug delivery, and therapeutic applications.

The genus Sobemovirus includes isometric, single-stranded positive sense RNA plant viruses that infect monocots and dicots. Sesbania mosaic virus (SeMV) is the only sobemovirus, which has been studied extensively in India. SeMV, which was identified in southern India, is highly stable and multiplies to high concentration causing mosaic symptoms on the leaves of Sesbania grandiflora. SeMV has served as a good model for understanding the molecular mechanism of assembly, replication and movement of sobemoviruses. The structure of the virion and other chimeric VLPs, along with biochemical investigations has resulted in the elucidation of the mechanism of assembly of SeMV. The complete genome sequence, structure and function of non-structural proteins have also been determined. The review presents a summary of all these findings. SeMV being non-toxic and biodegradable and of low immune response, has been shown as a good candidate for biomedical applications.

Sesbania mosaic virus (SeMV), a 30-nm spherical plant sobemovirus, is suitable for developing functionalized nanoparticles for biomedical applications. However, the in vivo behavior of SeMV and the clinical impact following its delivery via the oral or intravenous route are not known. To address this question, we examined the biodistribution, toxicity and histopathological changes in SeMV treated mice. No toxic effects were observed in mice administered high doses (100 mg and 200 mg per kg body weight orally or 40 mg and 80 mg per kg body weight intravenously) of SeMV, and they were found to be normal. Analysis of fecal sample showed that SeMV was cleared in 16 h when 20 mg of the virus per kg body weight was administered orally. RT-PCR analysis of blood samples showed that SeMV was present up to 72 h in mice inoculated either intravenously (8 mg/kg body weight) or orally (20 mg/kg body weight). Further, SeMV was found to be localized up to 72 h in spleen and liver tissues of intravenously inoculated mice only. Biochemical and hematological parameters were found to be normal at 6 and 72 h after administration of SeMV. Furthermore, no noticeable changes were observed in histological sections of brain, liver, spleen, lungs and kidney tissue samples collected at 6 and 72 h from SeMV administered mice when compared to control mice. Thus, SeMV appears to be a safe and non-toxic platform that can be tailored as a nanocarrier for in vivo biomedical applications.

A virus isolate associated with yellow mosaic disease was purified from commercially cultivated jasmine (Jasminum sambac) from Andhra Pradesh, India and it contained flexuous filamentous particles of ~720 × 13 nm. The denatured purified virus had single major polypeptide of molecular weight 32 kDa. Complementary DNA representing 1678 nucleotides (nt) of the 3′ terminus of viral RNA was cloned and sequenced. Comparisons of complete coat protein (CP) gene nucleotide and amino acid sequences of the present virus isolate with certain reported potyviruses revealed 86.1 and 92.7 % identity, respectively with jasmine potyvirus T (JaVT) reported from Taiwan and less than 70 % with other potyviruses. Based on the phylogenetic analysis of 3′ UTR and CP gene, the present virus isolate was identified as an isolate of JaVT that belongs to the genus Potyvirus and the name Jasmine yellow mosaic virus-Andhra Pradesh (JaYMV-AP) is proposed.