Hydrodynamics of bubble flow through a porous medium with applications to packed bed reactors

Gas-liquid flows through packed bed reactors (PBRs) are challenging to predict due to the tortuous flow paths that fluid interfaces must traverse. Experiments at the International Space Station showed that bubble and pulse flows are predominately observed under microgravity conditions, while trickle and spray flows observed under terrestrial conditions, are not present in microgravity. Toward understanding the physics behind the latter experiments, we simulate bubble flow through a PBR for different packing-particle-diameter-based Weber numbers and under different gravity conditions. We demonstrate different pore-scale mechanisms such as capillary entrapment, buoyancy entrapment, and inertia-induced bubble displacement. Then, we perform a quantitative analysis by introducing a new dynamic length scale, dependent upon the evolving gas-liquid interfacial area, to understand the dynamic trade-offs between the inertia, capillary, and buoyancy forces on a bubble passing through a PBR. This analysis leads us to define new dimensionless Weber-like numbers that delineate bubble entrapment from bubble displacement.Comment: 12 pages, 9 figure

Association of Genome-Wide Association Study (GWAS) identified SNPs and risk of breast cancer in an Indian population

To date, no studies have investigated the association of the GWAS-identified SNPs with BC risk in Indian population. We investigated the association of 30 previously reported and replicated BC susceptibility SNPs in 1,204 cases and 1,212 controls from a hospital based case-control study conducted at the Tata Memorial Hospital, Mumbai. As a measure of total susceptibility burden, the polygenic risk score (PRS) for each individual was defined by the weighted sum of genotypes from 21 independent SNPs with weights derived from previously published estimates of association odds-ratios. Logistic regression models were used to assess risk associated with individual SNPs and overall PRS, and stratified by menopausal and receptor status. A total of 11 SNPs from eight genomic regions (FGFR2, 9q31.2, MAP3K, CCND1, ZM1Z1, RAD51L11, ESR1 and UST) showed statistically significant (p-value = 0.05) evidence of association, either overall or when stratified by menopausal status or hormone receptor status. BC SNPs previously identified in Caucasian population showed evidence of replication in the Indian population mainly with respect to risk of postmenopausal and hormone receptor positive BC. © 2017 The Author(s)

Longitudinal association of inflammatory markers with markers of glycaemia and insulin resistance in European children

Purpose: Subclinical systemic inflammation may lead to development of type 2 diabetes, but there has been no investigation into its relationship with early progression of glycaemic deterioration and insulin resistance, especially in younger population. In this study we assessed longitudinal associations of pro- and anti-inflammatory markers with markers that evaluate glycaemia and insulin resistance. Methods: This study includes 6537 initially nondiabetic children (mean age at baseline = 6.2 years) with repeated measurements from the IDEFICS/I.Family cohort study (mean follow-up = 5.3 years) from eight European countries. Markers of inflammation were used as independent variables and markers of glycaemia/insulin resistance as dependent variables. Associations were examined using two-level growth model. Models were adjusted for sex, age, major lifestyle, metabolic risk factors, early life markers, and other inflammatory markers in final model. Results: Children with 6 years of follow-up showed that a one-unit increase in z-score of leptin level was associated with 0.38 (95% CI = 0.32 to 0.44) unit increase in HOMA-IR z-scores. Leptin continued to be associated with HOMA-IR even when analysis was limited to children with no overall obesity, no abdominal obesity, and low to normal triglyceride levels. An inverse association was observed between IL-15 and HOMA-IR (ß = -0.11, 95% CI = -0.15 to -0.07). Conclusions: IL-15 should be evaluated further in the prevention or treatment of prediabetes whereas leptin may prove to be useful in early detection of prediabetes via their association with markers of insulin resistance in European children

In-stent thrombosis after 68 months of implantation inspite of continuous dual antiplatelet therapy: a case report

Lately, there has been an increased incidence of late stent thrombosis; especially following Drug eluting stent (DES) implantation. Several factors are associated with an increased risk of stent thrombosis, including the procedure itself, patient and lesion characteristics, stent design, and premature cessation of anti-platelet drugs. We present a case of late stent thrombosis (LST) following DES implantation after a period of 68 months, making it the longest reported case of LST reported in the literature, despite the use of dual anti-platelet therapy

Wireless phone use in childhood and adolescence and neuroepithelial brain tumours: Results from the international MOBI-Kids study

In recent decades, the possibility that use of mobile communicating devices, particularly wireless (mobile and cordless) phones, may increase brain tumour risk, has been a concern, particularly given the considerable increase in their use by young people. MOBI-Kids, a 14-country (Australia, Austria, Canada, France, Germany, Greece, India, Israel, Italy, Japan, Korea, the Netherlands, New Zealand, Spain) case-control study, was conducted to evaluate whether wireless phone use (and particularly resulting exposure to radiofrequency (RF) and extremely low frequency (ELF) electromagnetic fields (EMF)) increases risk of brain tumours in young people. Between 2010 and 2015, the study recruited 899 people with brain tumours aged 10 to 24 years old and 1,910 controls (operated for appendicitis) matched to the cases on date of diagnosis, study region and age. Participation rates were 72% for cases and 54% for controls. The mean ages of cases and controls were 16.5 and 16.6 years, respectively; 57% were males. The vast majority of study participants were wireless phones users, even in the youngest age group, and the study included substantial numbers of long-term (over 10 years) users: 22% overall, 51% in the 20-24-year-olds. Most tumours were of the neuroepithelial type (NBT; n = 671), mainly glioma. The odds ratios (OR) of NBT appeared to decrease with increasing time since start of use of wireless phones, cumulative number of calls and cumulative call time, particularly in the 15-19 years old age group. A decreasing trend in ORs was also observed with increasing estimated cumulative RF specific energy and ELF induced current density at the location of the tumour. Further analyses suggest that the large number of ORs below 1 in this study is unlikely to represent an unknown causal preventive effect of mobile phone exposure: they can be at least partially explained by differential recall by proxies and prodromal symptoms affecting phone use before diagnosis of the cases. We cannot rule out, however, residual confounding from sources we did not measure. Overall, our study provides no evidence of a causal association between wireless phone use and brain tumours in young people. However, the sources of bias summarised above prevent us from ruling out a small increased risk