Search

Cocoa is a commercially important beverage crop that faces new challenges in the context of climate change, which can alter pest and disease dynamics in cocoa plantations. In the Dakshina Kannada district of Karnataka, India, an abrupt increase in cocoa wilt was observed during the 2017–18 and 2018–19 seasons. Systematic examination of affected trees revealed consistent attacks of Euwallacea perbrevis (Schedl, 1951; Coleoptera: Curculionidae: Scolytinae). In-depth studies of the wilted trees revealed the association of the plant pathogenic fungus Fusarium sp. with Euwallacea perbrevis. The identity of the obtained pure culture from the insect and infected tree was confirmed as Fusarium sp. using amplification of ribosomal DNA, RNA polymerase II largest subunit (RPB1) and translation elongation factor 1 (Tef1) genes. Notably, this study reports a remarkable case of mutualistic association between ambrosia beetles and Fusarium sp., belonging to the Fusarium solani species complex (FSSC), rather than the Ambrosia Fusarium clade (AFC). This finding highlights the intriguing diversity of mutualistic relationships in nature and sheds new light on the complex interactions between organisms. The present study also investigated the impact of rainfall on the colonization and spread of the Euwallacea-Fusarium complex. The findings revealed that rainfall was identified as a predisposing factor for the incidence and spread of attacks. Additionally, the study conducted a comprehensive analysis of the modeling of Euwallacea-Fusarium complex spread over a specific period of time. • An abrupt increase in cocoa wilt was documented in Karnataka, India during the periods 2017–2019. • Investigation unveiled incidence of Euwallacea fornicates , an ambrosia beetle, and Fusarium sp. fungus, belonging to the Fusarium solani species complex. • The study identified rainfall as a predisposing factor for the incidence and spread of Euwallacea - Fusarium complex. • This is the first report of Euwallacea - Fusarium complex causing wilt disease of cocoa in India. [ABSTRACT FROM AUTHOR]

Arecanut is a prominent cash crop in India, known for its potential to significantly boost per capita income. The presence of fungal diseases poses a significant constraint to arecanut cultivation. In October 2019, a severe outbreak of leaf spot disease with 90°% disease incidence was recorded in the farmer's arecanut gardens from Kalasa hobli, Chikkamangaluru, Karnataka, India. Leaf spot symptoms started as small, irregular, light-dark brown spots (3–10 mm in diameter) with a yellow halo on the leaf lamina, which later coalesced to form larger necrotic lesions and a blighted appearance. The symptoms were also observed on leaf sheaths and nuts. In the present study, we identified and characterized the pathogen causing leaf spot disease using cultural, morphological, molecular characterization using multi-gene phylogeny, and pathogenicity assays. Microscopic, and molecular identification of CPCRICkc7G isolate retrieved from the leaf spot infected sample established the association of Colletotrichum kahawae subsp. cigarro as the causal agent. Pathogenicity assays confirmed the Koch's postulate by reproducing the field observed symptoms. To best of our knowledge, this confirms the first report of C. kahawae subsp. cigarro causing leaf spot disease on arecanut in India. The findings from this current study play a pivotal role in enhancing the knowledge of arecanut diseases in India, and lay an essential foundation for devising effective disease management approaches to curtail the disease spread. • Severe leaf spot disease hits arecanut gardens in Karnataka, India, with 90°% incidence. • Colletotrichum kahawae subsp. cigarro identified as the pathogen using cultural, morphological, and molecular characterization. • This is the first report of Colletotrichum kahawae subsp. cigarro causing leaf spot disease of arecanut in India. • This report has established a crucial groundwork for formulating effective disease management strategies. [ABSTRACT FROM AUTHOR]

Fruit rot disease (FRD) of arecanut caused by Phytophthora meadii (McRae) is a major limiting factor in arecanut production across the globe. Prophylactic sprayings of Bordeaux mixture (1%) and other oomycete-specific fungicides are recommended to manage this serious malady in arecanut. However, the tall nature of palms is a greater challenge for the application of plant protection measures on fruit bunches. Manual climbing of the palms during the rainy season is yet another risky task for proper spraying of chemicals up to the crown region. In this context, fungicide-loaded urea briquettes (FAUB's) were developed and assessed under field conditions against FRD in arecanut. Results proved that systemic fungicide-based urea briquettes are highly potent in protecting arecanut from FRD infection. Meanwhile, in the modern fungicidal delivery approach, the ambient fungicides such as fosetyl-Al, a combination of fosetyl-Al - propineb briquettes had achieved stronger fungicidal activity against FRD, reducing severity by 70% when applied twice with increased dry nut yield of 100% compared to control plots. Fosetyl-al briquettes found significantly higher in terms of control efficiency (Severity of 8.5 ± 0.22, 80%), yield response (19.04 ± 0.39q/ha), and economic analysis (3,08,400 Rs./ha). Further, the present study demonstrated that the soil application of FAUB's is an alternative to arduous conventional spraying. The experiment proved and demonstrated that, FAUB's could potential replacement for Bordeaux mixture and copper-oxychloride application under field conditions. Hence, we recommend to implement in integrated FRD management program. • Systemic-fungicidal briquettes are highly potent in arecanut FRD management. • Soil application of FAUB's is an alternative method to arduous conventional spraying. • FAUB's is farmer's friendly and environmentally safest approach. • FAUB's – first elaborately studied technology on arecanut FRD management. [ABSTRACT FROM AUTHOR]

The effect of fenugreek seeds (Trigonella foenum graecum) compared to omeprazole was studied on ethanol-induced gastric ulcer. The aqueous extract and a gel fraction isolated from the seeds showed significant ulcer protective effects. The cytoprotective effect of the seeds seemed to be not only due to the anti-secretory action but also to the effects on mucosal glycoproteins. The fenugreek seeds also prevented the rise in lipid peroxidation induced by ethanol presumably by enhancing antioxidant potential of the gastric mucosa thereby lowering mucosal injury. Histological studies revealed that the soluble gel fraction derived from the seeds was more effective than omeprazole in preventing lesion formation. These observations show that fenugreek seeds possess antiulcer potential. [Copyright &y& Elsevier]

• Cu-Al-Fe-Mn quaternary shape memory alloy was prepared in a vacuum induction furnace. • CO 2 laser machining of the quaternary shape memory alloy was performed. • Influence on the laser beam parameters on the quaternary SMA has been analysed. • Shape memory properties and surface topography after laser machining was also carried out. Shape Memory Alloys (often called SMAs) belong to a branch of alloys that "remember" their original shape. When the metals are twisted or disturbed from their initial shape, they are capable of coming back to their original shape on application of external stimuli such as magnetic field, heat or stress. Despite its widespread commercialization, Ni-Ti is considered a costly alternative. As a result, cost-effective and easy-to-process alloys such as Cu- and Fe-based alloys are currently being investigated. Processing of Fe-based alloys is difficult as their properties are texture dependant. Cu-based shape memory alloys are thus considered viable alternatives. So the unconventional machining operations like electrical discharge machining (EDM) and laser machining can also be used to manufacture Cu-based SMA components. But thermal machining operations like IBM (ion beam machining), EBM (electron beam machining), LBM (laser beam machining), PAM (plasma arc machining) and EDM (electrical discharge machining) removes material from the surface of the work piece through melting/vaporization. However, thermal damage such as the heat affected zone is brought on by the intense heat flow in laser machining. Hence only a few works have been reported to differentiate and characterize the varied properties of the SMA machined through laser machining. This research work aims at optimizing the laser beam machining parameters and study its influence on surface characteristics and shape memory properties of Cu-based SMA. Based on the experiments carried out using L 9 orthogonal array design matrix, optimal parameters were found out with response tables and graphs which is further analysed using grey relational analysis. Surface topography was analysed by scanning electron microscope (SEM). Differential scanning calorimetry (DSC) was used to investigate phase transformation temperatures and some thermodynamic parameters. X-Ray Diffraction (XRD) was also performed to find out the different phases that are present. The results showed the grey relational analysis coupled with Taguchi approach is an effective and convenient technique to optimize the laser machining parameters and achieve better results. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive examination of the Cd 0.90 Mn 0.10 Te (CMT) single crystal in its role as a radiation detector. Covering aspects from the growth process to detector performance, the primary emphasis is placed on ensuring the uniformity of composition along the growth axis. A cost-effective custom-built vertical Bridgman (VB) setup is developed for the growth of highly homogeneous Cd 0.90 Mn 0.10 Te (CMT) single crystal. CMT single crystals of 10 mm diameter and 130 mm length with near uniform stoichiometry along the growth axis were grown using VB method. Laue diffraction confirms the single crystallinity of the grown crystal. The measured lattice constant is comparable to the theoretical value calculated using Vegard's law. The two mode vibrations of the CdTe and MnTe sublattices were confirmed by Raman spectroscopy. The observed high optical transmittance in the mid-infra-red (IR) region and a nearly constant bandgap of ∼1.6 eV for the wafers taken at different locations along the growth axis reveals the IR transparency and compositional uniformity of the grown crystal. The energy dispersive X-ray spectroscopy proved that the elemental distribution is uniform in the grown crystal. The IR microscopic imaging shows Te inclusions with a number density in the range of ∼2.6–4.5 × 104 cm−2. The resistivity of the CMT crystal for all wafers was found to be in the order of 109 Ωcm. The γ–ray spectral resolution of ∼22 % of 59.5 keV irradiation from 241Am source is achieved. [Display omitted] • Detector grade Cd 0.90 Mn 0.10 Te crystal grown by home-built vertical Bridgman method. • Vertical bobbing was used for the first time to synthesise the starting material. • Excellent structural and compositional homogeneity observed across crystal length. • CMT crystal displays good response to 241Am γ-irradiation with energy of 59.5 keV. [ABSTRACT FROM AUTHOR]

Abstract: Tribological behavior of TiAlN coating is investigated while sliding against 100Cr6 steel, SiC and Al2O3 counterbodies. Depending upon the type of counterbody used, two distinct types of wear modes such as oxidational and plastic deformation could be clearly observed. Wear of metal debris tribochemically reacted with moisture available in ambient atmosphere and formed metal oxide that caused oxidational wear in TiAlN/steel sliding pair. In TiAlN/SiC sliding pair, low friction coefficient ~0.17 was measured and this is attributed to the formation of a lubricious composite tribofilm. In contrast, TiAlN/Al2O3 sliding pair showed high friction coefficient and the wear mechanism is predominantly governed by plastic deformation. [Copyright &y& Elsevier]

In the present work, hydrophobic (contact angle ∼108°) poly methyl methacrylate (PMMA) films were developed by a simple room temperature drop-cast method based on slow solvent evaporation process. Further, PMMA nanocomposites (NCs) were developed by impregnating PMMA with nanoparticles (0.1% w/v) of copper oxide (CuO), cetyltrimethyl ammonium bromide (CTAB) capped CuO (CuO-CTAB) and zinc oxide (ZnO). The PMMA and NCs were tested against attachment of marine bacteria, microalgae (diatoms) and barnacle larvae in laboratory as well as in the sea. At low loading of nanoparticles (0.1% w/v), the PMMA NCs inhibited bacterial settlement (24 h assay) by 97–99% in the laboratory and by 40–69% in the field exposure studies. They also inhibited diatom attachment (24–38%) in laboratory and in the sea (80–95%). NCs successfully inhibited (100%) barnacle settlement and metamorphosis and caused mortality to the extent of 22–44% in exposed cypris larvae. Incorporation of nanoparticles in PMMA confers antifouling property to the polymer at greatly reduced metal release rates as compared to conventional antifouling paints. Results of the study indicate that PMMA NCs are promising as low cost antifouling coatings for static moored/submerged structures in the ocean due to their efficacy at low environmental metal release. [ABSTRACT FROM AUTHOR]

Tribo-tests were carried out on pyrolyted wood derived charcoal specimen in the directions of “flat-face” and “curved-face”. In former direction, an ultra-low friction coefficient 0.03 was measured in a high humid condition with 75% relative humidity. Eventually, the friction coefficient becomes 0.45 when the humidity level decreased to 10%. However, under similar tribo-test condition, the friction coefficient is high 0.1 in the “curved-face” of charcoal specimen at 75% humidity. This value further increased to 0.8 at humidity level of 10%. Large amount of polar functional groups, oxygen complexes and water molecules was observed on the “flat-face” due to the presence of microscopic pores which act as a reservoir to lubricate the sliding surfaces. [ABSTRACT FROM AUTHOR]