Droplet Impact and Spreading on Inclined Surfaces.

Introducing surface inclination in the case of droplet impact on solid substrates results in complicated dynamics post impact. The present work investigates the dynamics involved in the spreading phase of the droplet on inclined substrates. Experiments are conducted with water droplets impinging on inclined dry solid substrates with varying wettability values. The results reveal the presence of three phases in the droplet spread behavior. In the first phase, the droplet is observed to depict a close radial symmetry and is dominated by inertia forces. Phase 1 ends when the upstream droplet lamella post impact gets pinned to the surface or starts retracting as a consequence of surface forces becoming dominant. A scaling analysis developed to predict the pinning time of the droplet shows that the pinning time is independent of impact velocity, which is also observed during experiments. The asymmetries in the radial evolution of the droplet appear in phase 2 and become dominant in phase 3. Phase 2 terminates when the droplet attains the maximum lateral spread, which is established as a function of the normal component of the Weber number. Phase 3 is initiated when the droplet starts retracting in the lateral direction while the longitudinal expansion continues. Using an energy-based model constructed to predict the maximum spread, we show that the impact inertia of the droplet controls the longitudinal droplet spread in phases 1 and 2, while the gravity forces are primarily responsible for the droplet spread in phase 3. The model results were validated with the experiments conducted in-house and were found to be in good agreement.

Corrigendum: Anti-biofilm and Antibacterial Activities of Silver Nanoparticles Synthesized by the Reducing Activity of Phytoconstituents Present in the Indian Medicinal Plants.

[This corrects the article DOI: 10.3389/fmicb.2020.01143.].

Anti-biofilm and Antibacterial Activities of Silver Nanoparticles Synthesized by the Reducing Activity of Phytoconstituents Present in the Indian Medicinal Plants.

Biofilm forming from a variety of microbial pathogens can pose a serious health hazard that is difficult to combat. Nanotechnology, however, represents a new approach to fighting and eradicating biofilm-forming microorganisms. In the present study, the sustainable synthesis and characterization of biocompatible silver nanoparticles (AgNPs) from leaf extracts of Semecarpus anacardium, Glochidion lanceolarium, and Bridelia retusa was explored. Continuous synthesis was observed in a UV-vis spectroscopic analysis and the participating phytoconstituents, flavonoids, phenolic compounds, phytosterols, and glycosides, were characterized by Attenuated total reflectance-Fourier transform infrared spectroscopy. The size and surface charge of the particles were also measured by dynamic light scattering spectroscopy. Scanning electron microscopy study was employed to examine the morphology of the nanoparticles. The spectroscopic and microscopic study confirmed the successful synthesis of AgNPs by plant extracts acting as strong reducing agents. The synthesized AgNPs were screened for antibacterial and anti-biofilm activity against human pathogens Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. Results of the study demonstrate the potential of phyto-synthesized AgNPs to act as anti-biofilm agents and for other biomedical applications.

Evaluation of clinico-radiological, bacteriological, serological, molecular and histological diagnosis of osteoarticular tuberculosis.

BACKGROUND: The diagnosis of osteoarticular tuberculosis is clinico-radiological in endemic areas. However every patient does not have the classical picture. Osteoarticular tuberculosis is a paucibacillary disease hence bacteriological diagnosis is possible in 10-30% of the cases. The present study is undertaken to correlate clinico-radiological, bacteriological, serological, molecular and histological diagnosis. MATERIALS AND METHODS: Fifty clinico-radiologically diagnosed patients of osteoarticular tuberculosis with involvement of dorsal spine (n = 35), knee (n = 8), shoulder (n = 1), elbow (n = 2) and lumbar spine lesion (n = 4), were analyzed. Tissue was obtained after decompression in 35 cases of dorsal spine and fine needle aspiration in the remaining 15 cases. Tissue obtained was subjected to AFB staining, AFB culture sensitivity, aerobic/anaerobic culture sensitivity histopathological examination and polymerase chain reaction (PCR) using 16srRNA as primer. Serology was performed by ELISA in 27 cases of dorsal spine at admission and one and three months postoperatively. RESULTS: AFB staining (direct) and AFB culture sensitivity was positive in six (12%) cases. Aerobic/anaerobic culture sensitivity was negative in all cases. Histology was positive for TB in all the cases. The PCR was positive in 49 (98%) cases. All dorsal spine tuberculosis cases showed fall of IgM titer and rise of IgG titer at three months as compared to values at admission. CONCLUSION: Histopathology and PCR was diagnostic in all cases of osteoarticular tuberculosis. The serology alone is not diagnostic.