Electric Field-Induced "Tentillar" Bridging of a Droplet Twin.

Experimental investigations with high-speed imaging reveal that two unequal sized oppositely charged droplets suspended in an insulating oil can come in contact in an asymmetric manner under an electric field. The approaching poles of the droplets undergo asymmetric "cone-cone" to "cone-groove" deformations during noncoalescence under an electric field. Nonlinear three-dimensional simulations confirm the occurrence of a third "groove-groove" configuration at close proximity. A general linear stability analysis confirms the cone-cone to cone-groove transitions of the oil-water interfaces with decreasing thickness of the oil film. Experiments together with simulations confirm the bifurcation of the Taylor cone on the smaller droplet into a number of liquid "tentilla" bridges prior to contact with the bigger droplet. Simulations also predict that the length scales of the formation of such tentillar bridges from the initial Taylor cone match well with the predictions from the nonlinear bifurcation theory.

Interleukin-17 as a predictor of subclinical synovitis in the remission state of rheumatoid arthritis.

OBJECTIVES: To compare the level of pro and anti-inflammatory cytokines, and angiogenic mediators between Rheumatoid arthritis (RA) patients with and without subclinical synovitis (SS) in remission state, to find the correlation of these mediators with Greyscale synovitis (GSS) and power Doppler (PD) scores, and to find the probable predictor/s of SS. METHODS: 52 RA patients in remission state were recruited and subdivided into with and without SS group by Ultrasonography (USG) of 14 joints. Total GSS and PD scoring was done. The serum levels of the pro/anti-inflammatory cytokines and angiogenic mediators were compared between groups, and correlation and regression analysis were done with GSS and PD scores. RESULT: 63.46% patients had USG evidence of SS. Patients with SS had significantly higher levels of pro-inflammatory and angiogenic mediators [matrix-metalloproteinase -3 (p = 0.0001), Tumour necrosis factor-α (p = 0.0001), Interleukin (IL)-6 (p = 0.001), IL-1b (p = 0.0001), IL-17 (p = 0.0005), IL-33 (p = 0.0003), Tie-2 (p = 0.0001), vascular endothelial growth factor (VEGF (p = 0.03)], and lower anti-inflammatory cytokines [IL-27 (p = 0.0003), IL-10(p = 0.0001)]. A strong positive correlation of GSS score was noted with IL-17(r = 0.7), IL-6 (r = 0.7), IL-1b (r = 0.7), and IL-33 (r = 0.6). Multiple linear regression model identified IL-17 and IL-6 as predictors of GSS score, and TNF-α and VEGF as predictors of PD score. IL-17 level > 249 picogram/millilitre (pg/ml) could predict the SS with high specificity (89.5%). CONCLUSION: Patients with SS in the remission state of RA showed altered expression of some of the pro/anti-inflammatory/angiogenic markers compared to those not having SS. IL-17, IL-6, VEGF, and TNF-α could be the predictors of USG synovial scores.

A microfluidic viscometer: Translation of oscillatory motion of a water microdroplet in oil under electric field.

The electric field induced motion of a charged water droplet suspended in a low-dielectric oil medium is exploited to evaluate the rheological properties of the suspending medium. The time-periodic electrophoretic motion of the droplet between the electrodes decorated in a polymeric micro-well is translated into a proof-of-concept microfluidic prototype, which can measure viscosities of the unknown fluid samples. The variations in the instantaneous velocities of the migrating droplet have been measured inside silicone oil of known physical properties at different electric field intensities. Subsequently, a balance between the electric field to the viscous force has been employed to evaluate the experimental charge density on the droplet surface. Thereafter, a comprehensive scaling law has been devised to find a correlation between the charge on the droplet to the dielectric permittivity of the surrounding medium, size of the water droplet, and the applied electric field intensity. Following this, the scaling law and force balance have been employed together to evaluate the unknown viscosity of an array of suspending mediums by simply analyzing the electrophoretic motion of water droplet. The model proposed is also found to be consistent when a solid amberlite microparticle has been employed as a probe instead of the water droplet. In such a scenario, minor changes in the exponents of the scaling law are found to be necessary to reproduce the results obtained using the water droplet. The method paves the way for the making of an economical and portable microfluidic rheometer with further finetuning and translational developments.

An easy method for developing fusion enabled SARS-CoV2 virus fusion mimic (SCFM), bypassing the need of Bio Safety Level (BSL) facility.

Widespread infection due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has led to a global pandemic. Currently, various approaches are being taken up to develop vaccines and therapeutics to treat SARS-CoV2 infection. Consequently, the S protein has become an important target protein for developing vaccines and therapeutics against SARS-CoV2. However, the highly infective nature of SARS-CoV2 restricts experimentation with the virus to highly secure BSL3 facilities. The availability of fusion-enabled, nonreplicating, and nonbiohazardous mimics of SARS-CoV2 virus fusion, containing the viral S or S and M protein in their native conformation on mammalian cells, can serve as a useful substitute for studying viral fusion for testing various inhibitors of viral fusion. This would avoid the use of the BSL3 facility for fusion studies required to develop therapeutics. In the present study, we have developed SARS-CoV2 virus fusion mimics (SCFMs) using mammalian cells transfected with constructs coding for S or S and M protein. The fusogenic property of the mimic(s) and their interaction with the functional human ACE2 receptors was confirmed experimentally. We have also shown that such mimics can easily be used in an inhibition assay. These mimic(s) can be easily prepared on a large scale, and such SCFMs can serve as an invaluable resource for viral fusion inhibition assays and in vitro screening of antiviral agents, which can be shared/handled between labs/facilities without worrying about any biohazard while working under routine laboratory conditions, avoiding the use of BSL3 laboratory.Abbreviations :SCFM: SARS-CoV2 Virus Fusion Mimic; ACE2: Angiotensin-Converting Enzyme 2; hACE2: Human Angiotensin-Converting enzyme 2; MEF: Mouse Embryonic Fibroblasts; HBSS: Hanks Balanced Salt Solution; FBS: Fetal Bovine Serum.

Phenotypic characterization of circulating endothelial cells induced by inflammation and oxidative stress in ankylosing spondylitis.

Ankylosing spondylitis (AS) is a chronic auto-immune disease, affecting the spine, sacroiliac, and sometimes peripheral joints. It is also involved with cardio-vascular risk factors due to accelerated atherosclerosis. Oxidative burst, systemic inflammation coupled with endothelial dysfunction (ED), resulting in reduced bioavailability of the vasodilator nitric oxide (NO) and an increased number of circulating endothelial cells (CECs) may correlate with disease activity and its sustenance. Hence, the study was aimed to detect and quantify CECs and assess the oxidative stress and inflammatory status in AS patients vis-à-vis healthy controls, as well as relate these parameters with AS disease activity and atherosclerotic markers in patients. Our study showed an increased frequency of endothelial cells in peripheral blood of AS patients in pro-inflammatory conditions. In AS patient population, they showed significant reduction of flow-mediated dilatation (%FMD) (p < 0.05), and increased soluble adhesion molecules such as sICAM-1 (p < 0.01) and sVCAM-1 (p < 0.05) compared to healthy controls. A marked increase in pro-inflammatory markers such as TNF-α (p < 0.01) and IL-1ß (p < 0.001) and reactive free radicals (p < 0.05) along with reduced serum nitrite in AS, provided a strong pro-inflammatory milieu which positively correlated with Bath ankylosing spondylitis disease activity and functional indices (BASDAI and BASFI). The observed significant upregulation in CECs (CD45-/CD31+/CD105+/CD144+) in patients compared to healthy controls positively correlated with disease activity and duration as well as with markers of oxidative stress. Thus, chronic inflammation and oxidative burst induce loss of NO bioavailability, leading to ED. This may cause the derangement of CECs that may be considered as a prognostic biomarker for ED.

Assessment of nail unit structures by ultrasound in patients with psoriatic arthritis and their correlations with disease activity indices: a case-control study.

Ultrasound (USG) of nail was performed to assess, (1) morphological alterations of nail plates in psoriatic arthritis (PsA) patients, (2) differences of nail unit parameters [nail bed thickness (NBT), nail matrix thickness (NMT) and nail plate distance (NPD)] in PsA patients from healthy controls (3) correlation of nail unit parameters with PsA disease activity indices. Total of 895 fingernails (448 nails of 45 PsA patients and 447 of 45 controls) were evaluated by USG. Psoriasis Area and Severity Index (PASI), Disease Activity in Psoriatic Arthritis (DAPSA), and Nail Psoriasis Severity Index (NAPSI) were calculated in PsA patients. Nail unit parameters were compared between two study groups. Correlation study was done between nail unit parameters and disease activity indices. All PsA patients showed ultrasound evidence of nail plate changes (87.95% of the total fingernails and 75.34% of the clinically normal nails). Loosening of the ventral nail plate border was most common (51.79%). Mean NBT (PsA: 0.19 ± 0.035 cm, control: 0.17 ± 0.018 cm, p = 0.003) and mean NMT (PsA: 0.32 ± 0.041 cm, control: 0.28 ± 0.031 cm, p = < 0.0001) were significantly increased in the PsA patients. Moderately positive correlation was observed between NAPSI score and mean NMT (Spearman r = 0.411, 95% confidence interval: 0.125-0.634, p = 0.005). USG evidence of nail plate alterations was frequent among PsA patients, even in clinically normal nails. Increased mean nail bed and matrix thickness were noted in PsA patients. Mean NMT had a moderately positive correlation with NAPSI score.

Paper-based α-amylase detector for point-of-care diagnostics.

We report the fabrication of a paper-sensor for quantitative detection of α-amylase activity in human blood serum. Pieces of filter papers were coated with starch-iodine solution leading to an intense blue coloration on the surface. Dispensing α-amylase solution on the starch-iodine coated paper reduced the intensity of the color because of starch-hydrolysis catalyzed by amylase. The variation in the intensity of the color with the concentration of amylase was estimated in three stages: (i) initially, the paper-surface was illuminated with a light emitting diode, (ii) then, the transmitted (reflected) rays emitted through (from) the paper were collected on a photoresistor, and (iii) the variations in the electrical resistance of the photoresistor were correlated with the amylase concentration in analyte. The resistance of photoresistor decreased monotonically with an increase in amylase concentration because the intensity of the reflected (transmitted) rays collected from (through) the paper increased with reduction in the color intensity on the paper surface. Since a specific bio-reaction was employed to detect the activity of amylase, the sensor was found to be equally efficient in detecting unknown quantities of amylase in human blood serum. The reported sensor has shown the potential to graduate into a point-of-care detection tool for α-amylase.