Initial surface deformations during impact on a liquid pool

A tiny air bubble can be entrapped at the bottom of a solid sphere that impacts onto a liquid pool. The bubble forms due to the deformation of the liquid surface by a local pressure buildup inside the surrounding gas, as also observed during the impact of a liquid drop on a solid wall. Here we perform a perturbation analysis to quantitatively predict the initial deformations of the free surface of the liquid pool as it is approached by a solid sphere. We study the natural limits where the gas can be treated as a viscous fluid (Stokes flow) or as an inviscid fluid (potential flow). For both cases we derive the spatio-temporal evolution of the pool surface, and recover some of the recently proposed scaling laws for bubble entrapment. When inserting typical experimental values for the impact parameters, we find that the bubble volume is mainly determined by the effect of gas viscosity

Nonmonotonic settling of a sphere in a cornstarch suspension\ud

Cornstarch suspensions exhibit remarkable behavior. Here, we present two unexpected observations for a sphere settling in such a suspension: In the bulk of the liquid the velocity of the sphere oscillates around a terminal value, without damping. Near the bottom the sphere comes to a full stop, but then accelerates again toward a second stop. This stop-go cycle is repeated several times before the object reaches the bottom. We show that common shear thickening or linear viscoelastic models cannot account for the observed phenomena, and propose a minimal jamming model to describe the behavior at the botto

Universal mechanism for air entrainment during liquid impact

When a mm-sized liquid drop approaches a deep liquid pool, both the interface of the drop and the pool deform before the drop touches the pool. The build up of air pressure prior to coalescence is responsible for this deformation. Due to this deformation, air can be entrained at the bottom of the drop during the impact. We quantify the amount of entrained air numerically, using the Boundary Integral Method (BIM) for potential flow for the drop and the pool, coupled to viscous lubrication theory for the air film that has to be squeezed out during impact. We compare our results to various experimental data and find excellent agreement for the amount of air that is entrapped during impact onto a pool. Next, the impact of a rigid sphere onto a pool is numerically investigated and the air that is entrapped in this case also matches with available experimental data. In both cases of drop and sphere impact onto a pool the numerical air bubble volume V_b is found to be in agreement with the theoretical scaling V_b/V_{drop/sphere} ~ St^{-4/3}, where St is the Stokes number. This is the same scaling that has been found for drop impact onto a solid surface in previous research. This implies a universal mechanism for air entrainment for these different impact scenarios, which has been suggested in recent experimental work, but is now further elucidated with numerical results

Increased levels of ligands of Toll-like receptors 2 and 4 in type 1 diabetes

Type 1 diabetes is a proinflammatory state characterised by increased levels of circulating biomarkers of inflammation and monocyte activity. We have shown increased Toll-like receptor 2 (TLR2) and TLR4 expression and signalling in monocytes from type 1 diabetic patients. Several endogenous ligands of TLR2 and TLR4 have been identified; however, there is a paucity of data on levels of these endogenous ligands in diabetes. Thus, the aim of this study was to examine circulating levels of exogenous/endogenous ligands of TLR2 and TLR4 in type 1 diabetic patients and to compare these with the levels in matched healthy controls. Healthy controls (n = 37) and type 1 diabetic patients (n = 34) were recruited, and a fasting blood sample was obtained. Circulating levels of endotoxin, heat-shock protein 60 (Hsp60), high-mobility group box 1 (HMGB1) and growth arrest-specific 6 (GAS6) proteins were assessed by ELISA, and TLR2 and TLR4 expression was determined by flow cytometry. Levels of the classical TLR4 ligand, endotoxin, were significantly elevated in type 1 diabetic patients compared with those in matched controls. Hsp60 and HMGB1 concentrations were also significantly increased in the patients (p < 0.01 and p < 0.001, respectively). No significant differences were observed in GAS6. We report the novel observation that levels of ligands of TLR2 and TLR4 are significantly elevated in type 1 diabetes, and this, in concert with hyperglycaemia, accounts for the increase in TLR2 and TLR4 activity, underscoring the proinflammatory state of type 1 diabetes

Evaluating disease severity in idiopathic pulmonary fibrosis.

Accurate assessment of idiopathic pulmonary fibrosis (IPF) disease severity is integral to the care provided to patients with IPF. However, to date, there are no generally accepted or validated staging systems. There is an abundance of data on using information acquired from physiological, radiological and pathological parameters, in isolation or in combination, to assess disease severity in IPF. Recently, there has been interest in using serum biomarkers and computed tomography-derived quantitative lung fibrosis measures to stage disease severity in IPF. This review will focus on the suggested methods for staging IPF, at baseline and on serial assessment, their strengths and limitations, as well as future developments

Drug utilization study in ophthalmology out patients in a tertiary care teaching hospital

Background: The objective of the study was to evaluate the utilization of the drugs in the ophthalmology outpatient department.Methods: Present study was conducted at ESIC medical college & PGIMSR Ophthalmology Department. Total 700 prescriptions were collected from 700 patients and prescriptions were analysed for total and average number drugs per prescription, duration of treatment, dosage form, drug encounter with antibiotics and other group of drugs also percentage of drugs prescribed by generic names.Results: After analysing the prescriptions, average number of drugs per prescription was 2.14 and the range of drugs prescribed were varied from 1-5. Total drugs prescribed were 1502 with 7 different dosage forms. Most commonly prescribed were antibiotics (28.14%) followed by antihistamines (14.28%) and vitamins and minerals (14.28%). Thirdly ocular lubricants were frequently prescribed (12.12%). Fluroquinolones (moxifloxacin) were very commonly prescribed in antibiotics. The common prescription writing errors were very minimal.Conclusions: The present study revealed trend of prescribing practices of the Opthalmologists of the Institute. This study shows less polypharmacy, use of injection was limited and majority of the drugs prescribed in generic and hospital formulary drug list. Antibiotics were prescribed most frequently

Correlation of lipid profile and anthropometry with aortic intima-media thickness in newborns of diabetic and non-diabetic mothers

Background: Exposure to diabetes in utero has been established as a significant factor for certain component of the clinical syndrome. Although complications of atherosclerosis occur in adult life, the process begins in early childhood. Hence, measuring aortic intima-media thickness (AIMT) in the newborn is a feasible, accurate, and sensitive marker of atherosclerotic risk. Objective: The objective of the study was to find an association of AIMT with cord blood lipid levels and anthropometric factors. Methods: Babies born to diabetic mothers (gestational diabetes mellitus/type 2 diabetes mellitus (34 weeks–42 weeks) who were taken as one group and babies born to non-diabetic mothers (34 weeks–42 weeks) who were taken as the other group were enrolled in this study. Lipid values were measured of umbilical cord blood, collected immediately after delivery. Atherogenic-indices were calculated; neonatal anthropometric measurements were taken within 24 h after delivery. Abdominal AIMT (aAIMT) was measured within 4 days of delivery using a high-resolution ultrasound B mode by a trained radiologist. Maternal age, parity, height, pre-pregnancy weight, gestational age, and other investigations were taken from maternal records. Results: In this study, birth weight (BW) was positively correlated with triglycerides (TG), cholesterol, high-density lipoprotein (HDL), very low-density lipoprotein (VLDL), and atherogenic-indices, whereas, it was negatively correlated with low-density lipoprotein (LDL) (p<0.01). A positive correlation was found between aAIMT and BW, abdominal circumference, TG, cholesterol, HDL, LDL, VLDL, and atherogenic-indices (p<0.001). Conclusions: In this study, infants born to diabetic mothers had higher anthropometry, lipid values, aAIMT compared to babies born to non-diabetic mothers without risk factors

Approach to Universality in Axisymmetric Bubble Pinch-Off

The pinch-off of an axisymmetric air bubble surrounded by an inviscid fluid is compared in four physical realizations: (i) cavity collapse in the wake of an impacting disc, (ii) gas bubbles injected through a small orifice, (iii) bubble rupture in a straining flow, and (iv) a bubble with an initially necked shape. Our boundary-integral simulations suggest that all systems eventually follow the universal behavior characterized by slowly varying exponents predicted in [Eggers et al., PRL 98, 094502 (2007)]. However, the time scale for the onset of this final regime is found to vary by orders of magnitude depending on the system in question: while for the impacting disc it is well in the millisecond range, for the gas injection needle universal behavior sets in only a few microseconds before pinch-off. These findings reconcile the different views expressed in recent literature about the universal nature of bubble pinch-off