22 research outputs found

    A review of remotely sensed satellite image classification

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    Satellite image classification has a vital role for the extraction and analysis of the useful satellite image information. This paper comprises the study of the satellite images classification and Remote Sensing along with a brief overview of the previous studies that are proposed in this field. In this paper, the existing work has been explained utilizing the classification techniques on satellite images of Alwar region in India that covers decent land cover features like Vegetation, Water, Urban, Barren, and Rocky regions. The post- implementation of the classification algorithms, the classified image is obtained displaying different classes that are represented by different colours. Each feature is represented by a different colour and can be easily perceived from the image obtained after classification. The focus of this study is on enhancing the classification accuracy by using proper classifiers along with the novel feature extraction techniques and pre-processing steps. Work of different authors is being discussed in a tabular form defining the methods and outcomes of the respective studies

    Mycobacterium tuberculosis Transcriptional Adaptation, Growth Arrest and Dormancy Phenotype Development Is Triggered by Vitamin C

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    BACKGROUND: Tubercle bacilli are thought to persist in a dormant state during latent tuberculosis (TB) infection. Although little is known about the host factors that induce and maintain Mycobacterium tuberculosis (M. tb) within latent lesions, O(2) depletion, nutrient limitation and acidification are some of the stresses implicated in bacterial dormancy development/growth arrest. Adaptation to hypoxia and exposure to NO/CO is implemented through the DevRS/DosT two-component system which induces the dormancy regulon. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that vitamin C (ascorbic acid/AA) can serve as an additional signal to induce the DevR regulon. Physiological levels of AA scavenge O(2) and rapidly induce the DevR regulon at an estimated O(2) saturation of <30%. The kinetics and magnitude of the response suggests an initial involvement of DosT and a sustained DevS-mediated response during bacterial adaptation to increasing hypoxia. In addition to inducing DevR regulon mechanisms, vitamin C induces the expression of selected genes previously shown to be responsive to low pH and oxidative stress, triggers bacterial growth arrest and promotes dormancy phenotype development in M. tb grown in axenic culture and intracellularly in THP-1 cells. CONCLUSIONS/SIGNIFICANCE: Vitamin C mimics multiple intracellular stresses and has wide-ranging regulatory effects on gene expression and physiology of M. tb which leads to growth arrest and a 'dormant' drug-tolerant phenotype, but in a manner independent of the DevRS/DosT system. The 'AA-dormancy infection model' offers a potential alternative to other models of non-replicating persistence of M. tb and may be useful for investigating host-'dormant' M. tb interactions. Our findings offer a new perspective on the role of nutritional factors in TB and suggest a possible role for vitamin C in TB

    Appropriate DevR (DosR)-Mediated Signaling Determines Transcriptional Response, Hypoxic Viability and Virulence of Mycobacterium tuberculosis

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    Background: The DevR(DosR) regulon is implicated in hypoxic adaptation and virulence of Mycobacterium tuberculosis. The present study was designed to decipher the impact of perturbation in DevR-mediated signaling on these properties. Methodology/Principal Findings: M. tb complemented (Comp) strains expressing different levels of DevR were constructed in Mut1 * background (expressing DevR N-terminal domain in fusion with AphI (DevRN-Kan) and in Mut2DdevR background (deletion mutant). They were compared for their hypoxia adaptation and virulence properties. Diverse phenotypes were noted; basal level expression (,5.362.3 mM) when induced to levels equivalent to WT levels (,25.869.3 mM) was associated with robust DevR regulon induction and hypoxic adaptation (Comp 9 * and 10*), whereas low-level expression (detectable at transcript level) as in Comp 11 * and Comp15 was associated with an adaptation defect. Intermediate-level expression (,3.361.2 mM) partially restored hypoxic adaptation functions in Comp2, but not in Comp1 * bacteria that coexpressed DevRN-Kan. Comp * strains in Mut1 * background also exhibited diverse virulence phenotypes; high/very low-level DevR expression was associated with virulence whereas intermediate-level expression was associated with low virulence. Transcription profiling and gene expression analysis revealed up-regulation of the phosphate starvation response (PSR) in Mut1 * and Comp11 * bacteria, but not in WT/Mut2DdevR/other Comp strains, indicating a plasticity in expression pathways that is determined by the magnitude of signaling perturbation through DevRN-Kan

    Figure 2 in Rhipicephalus (Boophilus) microplus (Arachnida: Ixodidae) larvae infestation of human eyelids. A rare case

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    Figure 2 Larvae of R. (B.) microplus.Published as part of Kaur, Navpreet, Prasher, Pawan, Kumar, Khushhal & Dhingra, Sakshi, 2019, Rhipicephalus (Boophilus) microplus (Arachnida: Ixodidae) larvae infestation of human eyelids. A rare case, pp. 21-25 in Acarologia 59 (1) on page 23, DOI: 10.24349/acarologia/20194309, http://zenodo.org/record/450283

    Figure 1 in Rhipicephalus (Boophilus) microplus (Arachnida: Ixodidae) larvae infestation of human eyelids. A rare case

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    Figure 1 Arrows showing the larvae ofRhipicephalus(B.) microplus attached to the upper eyelid of the right eye.Published as part of Kaur, Navpreet, Prasher, Pawan, Kumar, Khushhal & Dhingra, Sakshi, 2019, Rhipicephalus (Boophilus) microplus (Arachnida: Ixodidae) larvae infestation of human eyelids. A rare case, pp. 21-25 in Acarologia 59 (1) on page 22, DOI: 10.24349/acarologia/20194309, http://zenodo.org/record/450283

    Rhipicephalus (Boophilus) microplus (Arachnida: Ixodidae) larvae infestation of human eyelids. A rare case

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    Kaur, Navpreet, Prasher, Pawan, Kumar, Khushhal, Dhingra, Sakshi (2019): Rhipicephalus (Boophilus) microplus (Arachnida: Ixodidae) larvae infestation of human eyelids. A rare case. Acarologia 59 (1): 21-25, DOI: 10.24349/acarologia/20194309, URL: http://dx.doi.org/10.24349/acarologia/2019430

    DevR (DosR) binding peptide inhibits adaptation of Mycobacterium tuberculosis under hypoxia

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    DevR is a key regulator of the dormancy response in Mycobacterium tuberculosis (M. tb). Using DevR as bait to screen a phage display library, a peptide, DevRS1, was obtained. DevRS1 inhibited DevR-regulated transcription and survival of nonreplicating tubercle bacilli in a hypoxia model of dormancy. DevRS1 peptide-mediated inhibition demonstrates the efficacy of intercepting DevR function to block hypoxic adaptation of M. tb

    A comprehensive review on various techniques used for synthesizing nanoparticles

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    Nature is still the main focus of scientific and technological research, particularly in nanotechnology and because of its remarkable properties; nanotechnology has acquired much interest in recent years. This review focuses on up-to-date overview of classification of nanoparticles, characterization, methods of preparation, characterization and application of nanoparticles. Initial section of the review gives insight on various techniques for the synthesis nanoparticles, encompassing both bottom-up and top-down approaches. Different methods for the synthesis of nanoparticles are discussed in details. Highlighting the importance of controlling shape, size, and composition to develop nanoparticles and enhance the properties of nanoparticles. These properties include enhanced surface area, unique optical, electronic, and magnetic characteristics, as well as improved mechanical properties. Understanding these attributes is essential for harnessing nanoparticles in different applications effectively. Broad spectrum of applications for nanoparticles is also discussed. Additionally, nanoparticles have found applications in catalysis, environmental remediation, and antimicrobial coatings, contributing to sustainable development and environmental protection. Overall, nanoparticles represent a progressive area of research with tremendous potential for innovation and societal impact. Our evaluation will serve as a solid reference, assisting the scientific community to comprehend the discussed topic better by showing the role of each technique in a comparable manner. As the field of nanoparticles is constantly evolving, this review incorporates the latest research, developments, and advancements up to the time of its publication. A comprehensive understanding of their properties, synthesis and applications is decisive for realizing the full potential of nanoparticles in various scientific and industrial domains

    Multifaceted remodeling by vitamin C boosts sensitivity of Mycobacterium tuberculosis subpopulations to combination treatment by anti-tubercular drugs

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    Bacterial dormancy is a major impediment to the eradication of tuberculosis (TB), because currently used drugs primarily target actively replicating bacteria. Therefore, decoding of the critical survival pathways in dormant tubercle bacilli is a research priority to formulate new approaches for killing these bacteria. Employing a network-based gene expression analysis approach, we demonstrate that redox active vitamin C (vit C) triggers a multifaceted and robust adaptation response in Mycobacterium tuberculosis (Mtb) involving similar to 67% of the genome. Vit C-adapted bacteria display well-described features of dormancy, including growth stasis and progression to a viable but non-culturable (VBNC) state, loss of acid-fastness and reduction in length, dissipation of reductive stress through triglyceride (TAG) accumulation, protective response to oxidative stress, and tolerance to first line TB drugs. VBNC bacteria are reactivatable upon removal of vit C and they recover drug susceptibility properties. Vit C synergizes with pyrazinamide, a unique TB drug with sterilizing activity, to kill dormant and replicating bacteria, negating any tolerance to rifampicin and isoniazid in combination treatment in both in-vitro and intracellular infection models. Finally, the vit C multi-stress redox models described here also offer a unique opportunity for concurrent screening of compounds/combinations active against heterogeneous subpopulations of Mtb. These findings suggest a novel strategy of vit C adjunctive therapy by modulating bacterial physiology for enhanced efficacy of combination chemotherapy with existing drugs, and also possible synergies to guide new therapeutic combinations towards accelerating TB treatment
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