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Wheat is one of major cereal crops with paramount importance that is cultivated across the globe. Fusarium head blight (FHB) is a catastrophic disease of wheat which has recently risen to prominence due to its direct impact on the quality and quantity of wheat on a global scale. During a field survey conducted in Rabi 2021-22, wheat spikes showing characteristic symptoms of head blight were observed in northern parts of the Karnataka, India, in the districts Bagalkote, Belagavi and Dharwad. The infected spikelets from the heads with symptoms of infection were washed well in distilled water and surface sterilized using 1% sodium hypochlorite solution. They were further washed using sterilized distilled water to remove the traces of sodium hypochlorite. These spikelets were then transferred to sterile potato dextrose agar (PDA) plates under aseptic conditions. The plates were incubated at a temperature of 27±1°C for ten days to obtain good fungal growth. The fungus produced white to orangish pink, dense mycelia and hyaline septate hyphae. Macroconidia were sickle-shaped measuring 35.7 to 52.6 x 3.2 to 5.1 µm, dorsoventrally curved with an elongated basal cell ending in a prominent long foot; the apical cell was also elongated, tapered, slightly curved. Spores had 3 to 4 cells and formed on monophialide. Microconidia and chlamydospores were present only in a few isolates. Fungal genomic DNA was extracted from all the established isolates using CTAB (Cetyl-trimethyl ammonium bromide) method (Murray and Thompson, 1980). The ITS region of r-DNA and translation elongation factor-1 alpha ( TEF-1α ) genes of the ten isolates were amplified using ITS1/ITS4 primer pair (White et al. 1990) and the species-specific EF1F/EF1R primer pair (O'Donnell et al., 1998) respectively, to detect and distinguish within Fusarium species. The results exhibited 95% similarity with Fusarium poae with GenBank Accession No. XMO44849482.1. which was previously reported as a causal agent of Fusarium head blight of wheat in Georgia, USA. The TEF1-α sequences were deposited in the GenBank and the accession numbers from OP716756 to OP716765 were obtained. For the pathogenicity test, spore suspension containing a load of 10 8 conidia ml -1 was prepared from ten days old Fusarium poae culture and sprayed on the healthy wheat heads of the susceptible variety UAS-304 during anthesis stage by using hand atomizer. Control plants were sprayed in a similar manner with sterile distilled water. In order to enhance disease development and increase the accuracy of the evaluation, humidity was maintained for 72 hours post-inoculation period by covering each spike with a plastic bag and misting at least once daily. The characteristic head blight symptoms were observed in the inoculated wheat spikes. No symptoms were noticed in the water-treated control. The plants initially showed bleaching in single spikelet after seven days of inoculation, which eventually spread to the entire spike. After fourteen days of inoculation, the spikes showed blighted appearance with pinkish or orangish mass of mycelia grown on the affected region. The pathogen was further reisolated from the infected plants and examined under the microscope. The similar morphological features as that of the originally inoculated pathogen was observed, hence fulfilling Koch's postulates. To our knowledge, this is the first report of Fusarium poae causing head blight of wheat in India. Keeping the current climate change scenario in view, the plausibility of this pathogen causing a major havoc in the near future must not be ignored, considering the fact that it has a wide host range and highly evolving nature. The ubiquity of the Fusarium head blight recently in northern parts of Karnataka urges the need to conduct further studies on the variability, distribution and management of the pathogen.

Wheat stem rust, caused by Puccinia graminis f. sp. tritici ( Pgt ), has re-emerged as one of the major concerns for global wheat production since the evolution of Ug99 and other virulent pathotypes of Pgt from East Africa, Europe, Central Asia, and other regions. Host resistance is the most effective, economic, and eco-friendly approach for managing stem rust. Understanding the virulence nature, genetic diversity, origin, distribution, and evolutionary pattern of Pgt pathotypes over time and space is a prerequisite for effectively managing newly emerging Pgt isolates through host resistance. In the present study, we monitored the occurrence of stem rust of wheat in India and neighboring countries from 2016 to 2022, collected 620 single-pustule isolates of Pgt from six states of India and Nepal, analyzed them on Indian stem rust differentials, and determined their virulence phenotypes and molecular genotypes. The Ug99 type of pathotypes did not occur in India. Pathotypes 11 and 40A were most predominant during these years. Virulence phenotyping of these isolates identified 14 Pgt pathotypes, which were genotyped using 37 Puccinia spp.-specific polymorphic microsatellites, followed by additional phylogenetic analyses using DARwin. These analyses identified three major molecular groups, demonstrating fewer lineages, clonality, and long-distance migration of Pgt isolates in India. Fourteen of the 40 recently released Indian wheat varieties exhibited complete resistance to all 23 Pgt pathotypes at the seedling stage. Twelve Sr genes were postulated in 39 varieties based on their seedling response to Pgt pathotypes. The values of slow rusting parameters i.e. coefficient of infection, area under disease progress curve, and infection rates, assessed at adult plant stage at five geographically different locations during two crop seasons, indicated the slow rusting behavior of several varieties. Six Sr genes ( Sr2 , Sr57 , Sr58 , Sr24 , Sr31 , and Sr38 ) were identified in 24 wheat varieties using molecular markers closely linked to these genes. These findings will guide future breeding programs toward more effective management of wheat stem rust., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Prasad, Thakur, Bhardwaj, Savadi, Gangwar, Lata, Adhikari, Kumar, Kundu, Manjul, Prakasha, Navathe, Hegde, Game, Mishra, Khan, Gupta, Mishra, Kumar, Kumar and Singh.)

This paper presents the development of a novel wavefront measuring camera capable of detecting both the amplitude and phase of the captured light wave simultaneously. The main objective of the present work is to develop a simple "aim and shoot" camera system for quantitative estimation of density variations in high-speed gas flow fields. The interrogating beam which is a plane wave used here gets distorted by flow induced change in refractive index gradients. Wavefront distortion is quantitatively measured by inspecting the projected pattern through the embedded mask of a modified CMOS image sensor, which samples the incoming wavefront space continuously. Post-processing of the captured images through Fourier- and windowed Fourier transform schemes reveals the change in phase and amplitude of the captured wave. The captured phase of the wavefront is used in an iterative tomography scheme to estimate the density distribution of the flow field. The utility of the developed camera is demonstrated in the quantitative visualization of the high-speed flow fields around test objects subjected to hypersonic flows at Mach numbers 8.89 and 5.82 in hypersonic shock tunnel facility (HST2) and also to visualize the flow field generated at the exit of a convergent-divergent nozzle (Mach number 2.9). It is observed that the recovered quantitative density values from the experiments match well with the results obtained through computational fluid dynamic simulations demonstrating the proficiency of the proposed wavefront measuring camera for high-speed flow diagnostics.

A method for quantitative estimation of density variation in high-speed flow, which uses light as an interrogating tool, is described. The wavefront distortion of the interrogating beam induced by the compressible flow field is estimated quantitatively, in which the density gradient of the flow field is seen as refractive-index gradient by the probing beam. The distorted wavefront is measured quantitatively by using the cross-sectional intensities of the distorted wavefront along the optical axis. Iterative algorithms are developed using both deterministic (Gauss-Newton) and stochastic (ensemble Kalman filter) update strategies to recover unknown parameters such as the phase of the wavefront or the refractive index distribution in the flow directly from the measured intensities. With phase recovered in the first step, a ray tomography algorithm is used to obtain the refractive index and density distributions in the flow from the phase. Experiments are conducted to quantitatively visualize the shock-wave-induced flow field in a shock-tunnel facility. The reconstructed density cross sections, obtained using different reconstruction methods, are presented and compared with those obtained by solving the Navier-Stokes equation using computational fluid dynamic routines. It is observed that the iterative algorithms always outperform those depending on solution of the transport-of-intensity equation. In particular, when using the iterative algorithms, the stochastic search scheme outperforms the Gauss-Newton method.

A simple noninterferometric optical probe is developed to estimate wavefront distortion suffered by a plane wave in its passage through density variations in a hypersonic flow obstructed by a test model in a typical shock tunnel. The probe has a plane light wave trans-illuminating the flow and casting a shadow of a continuous-tone sinusoidal grating. Through a geometrical optics, eikonal approximation to the distorted wavefront, a bilinear approximation to it is related to the location-dependent shift (distortion) suffered by the grating, which can be read out space-continuously from the projected grating image. The processing of the grating shadow is done through an efficient Fourier fringe analysis scheme, either with a windowed or global Fourier transform (WFT and FT). For comparison, wavefront slopes are also estimated from shadows of random-dot patterns, processed through cross correlation. The measured slopes are suitably unwrapped by using a discrete cosine transform (DCT)-based phase unwrapping procedure, and also through iterative procedures. The unwrapped phase information is used in an iterative scheme, for a full quantitative recovery of density distribution in the shock around the model, through refraction tomographic inversion. Hypersonic flow field parameters around a missile-shaped body at a free-stream Mach number of ∼8 measured using this technique are compared with the numerically estimated values. It is shown that, while processing a wavefront with small space-bandwidth product (SBP) the FT inversion gave accurate results with computational efficiency; computation-intensive WFT was needed for similar results when dealing with larger SBP wavefronts.

Microneedle technology is one of the attractive methods in transdermal drug delivery. However, the clinical applications of this method are limited owing to: complexity in the preparation of multiple coating solutions, drug leakage while inserting the microneedles into the skin and the outer walls of the solid microneedle can hold limited quantity of drug. Here, the authors present the fabrication of an array of rectangular cup shaped silicon microneedles, which provide for reduced drug leakage resulting in improvement of efficiency of drug delivery and possibility of introducing multiple drugs. The fabricated solid microneedles with rectangular cup shaped tip have a total height of 200 μm. These cup shaped tips have dimensions: 60 × 60 μm (length × breadth) with a depth of 60 μm. The cups are filled with drug using a novel in-house built drop coating system. Successful drug dissolution was observed when the coated microneedle was used on mice. Also, using the above method, it is possible to fill the cups selectively with different drugs, which enables simultaneous multiple drug delivery.

The sensing of carbon dioxide (CO2) at room temperature, which has potential applications in environmental monitoring, healthcare, mining, biotechnology, food industry, etc., is a challenge for the scientific community due to the relative inertness of CO2. Here, we propose a novel gas sensor based on clad-etched Fiber Bragg Grating (FBG) with polyallylamine-amino-carbon nanotube coated on the surface of the core for detecting the concentrations of CO2 gas at room temperature, in ppm levels over a wide range (1000 ppm-4000 ppm). The limit of detection observed in polyallylamine-amino-carbon nanotube coated core-FBG has been found to be about 75 ppm. In this approach, when CO2 gas molecules interact with the polyallylamine-amino-carbon nanotube coated FBG, the effective refractive index of the fiber core changes, resulting in a shift in Bragg wavelength. The experimental data show a linear response of Bragg wavelength shift for increase in concentration of CO2 gas. Besides being reproducible and repeatable, the technique is fast, compact, and highly sensitive.