Caustic formation in a non-Gaussian model for turbulent aerosols

Caustics in the dynamics of heavy particles in turbulence accelerate particle collisions. The rate $\mathscr{J}$ at which these singularities form depends sensitively on the Stokes number St, the non-dimensional inertia parameter. Exact results for this sensitive dependence have been obtained using Gaussian statistical models for turbulent aerosols. However, direct numerical simulations of heavy particles in turbulence yield much larger caustic-formation rates than predicted by the Gaussian theory. In order to understand possible mechanisms explaining this difference, we analyse a non-Gaussian statistical model for caustic formation in the limit of small St. We show that at small St, $\mathscr{J}$ depends sensitively on the tails of the distribution of Lagrangian fluid-velocity gradients. This explains why different authors obtained different St-dependencies of $\mathscr{J}$ in numerical-simulation studies. The most-likely gradient fluctuation that induces caustics at small St, by contrast, is the same in the non-Gaussian and Gaussian models. Direct-numerical simulation results for particles in turbulence show that the optimal fluctuation is similar, but not identical, to that obtained by the model calculations.Comment: 12 pages, 3 figures, 1 tabl

Pengaruh Bubuk Daun Kenikir (Cosmos Caudatus) Terhadap Kadar Malondialdehyde Plasma Tikus Wistar Diabetes Diinduksi Streptozotocin

Latar Belakang: Komplikasi vaskular diabetes terjadi akibat meningkatnya pembentukan radikal bebas sehingga menyebabkan stress oksidatif. Parameter tingkat stress oksidatif paling stabil adalah malondialdehyde (MDA). Stress oksidatif dapat dikendalikan dengan meningkatkan konsumsi antioksidan nonenzimatik. Daun kenikir memiliki zat antioksidan nonenzimatik potensial golongan flavonoid yaitu kuersetin. Penelitian ini bertujuan menganalisis pengaruh bubuk daun kenikir terhadap kadar malondialdehyde plasma tikus Wistar diabetes diinduksi streptozotocin.Metode: Jenis penelitian ini adalah true experimental dengan post-test only randomized control group design. Subjek penelitian yaitu 21 ekor tikus Wistar jantan dibagi menjadi 3 kelompok, K+, P1, dan P2. Seluruh kelompok diinduksi streptozotocin 65 mg/kg dan nicotinamide 230 mg/kg, kelompok perlakuan diberi bubuk daun kenikir dosis 700 mg/200gBB/hari dan 1400 mg/200gBB/hari selama 21 hari. Pemeriksaan kadar MDA plasma dengan metode 2-Thiobarbituric Acid Reactive Substance (TBARS). Data dianalisis menggunakan uji One Way Anova dan Post-hoc LSD.Hasil: Dosis 700 mg (P1) dan 1400 mg (P2) bubuk daun kenikir mampu menurunkan kadar MDA plasma tikus Wistar diabetes diinduksi streptozotocin (p<0,05). Rerata kadar MDA plasma kelompok kontrol positif sebesar 7,7±0,61, perlakuan 1 sebesar 6,1±0,58 dan perlakuan 2 sebesar 2,8±0,50. Secara statistik terdapat perbedaan rerata kadar MDA plasma antar kelompok (p<0,05).Simpulan: Bubuk daun kenikir dosis 700 mg/200gBB/hari dan 1400 mg/200gBB/hari selama 21 hari mampu menurunkan kadar MDA plasma tikus Wistar diabetes diinduksi streptozotocin. Dosis 1400 mg/200gBB/hari bubuk daun kenikir lebih efektif menurunkan kadar MDA plasma

Human Ontogeny of Drug Transporters: Review and Recommendations of the Pediatric Transporter Working Group

The critical importance of membrane-bound transporters in pharmacotherapy is widely recognized, but little is known about drug transporter activity in children. In this white paper, the Pediatric Transporter Working Group presents a systematic review of the ontogeny of clinically relevant membrane transporters (e.g., SLC, ABC superfamilies) in intestine, liver, and kidney. Different developmental patterns for individual transporters emerge, but much remains unknown. Recommendations to increase our understanding of membrane transporters in pediatric pharmacotherapy are presented

Primary Lung Dendritic Cell Cultures to Assess Efficacy of Spectinamide-1599 Against Intracellular Mycobacterium tuberculosis

There is an urgent need to treat tuberculosis (TB) quickly, effectively and without side effects. Mycobacterium tuberculosis (Mtb), the causative organism of TB, can survive for long periods of time within macrophages and dendritic cells and these intracellular bacilli are difficult to eliminate with current drug regimens. It is well established that Mtb responds differentially to drug treatment depending on its extracellular and intracellular location and replicative state. In this study, we isolated and cultured lung derived dendritic cells to be used as a screening system for drug efficacy against intracellular mycobacteria. Using mono- or combination drug treatments, we studied the action of spectinamide-1599 and pyrazinamide (antibiotics targeting slow-growing bacilli) in killing bacilli located within lung derived dendritic cells. Furthermore, because IFN-γ is an essential cytokine produced in response to Mtb infection and present during TB chemotherapy, we also assessed the efficacy of these drugs in the presence and absence of IFN-γ. Our results demonstrated that monotherapy with either spectinamide-1599 or pyrazinamide can reduce the intracellular bacterial burden by more than 99.9%. Even more impressive is that when TB infected lung derived dendritic cells are treated with spectinamide-1599 and pyrazinamide in combination with IFN-γ a strong synergistic effect was observed, which reduced the intracellular burden below the limit of detection. We concluded that IFN-γ activation of lung derived dendritic cells is essential for synergy between spectinamide-1599 and pyrazinamide

Large-scale genome-wide association studies and meta-analyses of longitudinal change in adult lung function.

BACKGROUND: Genome-wide association studies (GWAS) have identified numerous loci influencing cross-sectional lung function, but less is known about genes influencing longitudinal change in lung function. METHODS: We performed GWAS of the rate of change in forced expiratory volume in the first second (FEV1) in 14 longitudinal, population-based cohort studies comprising 27,249 adults of European ancestry using linear mixed effects model and combined cohort-specific results using fixed effect meta-analysis to identify novel genetic loci associated with longitudinal change in lung function. Gene expression analyses were subsequently performed for identified genetic loci. As a secondary aim, we estimated the mean rate of decline in FEV1 by smoking pattern, irrespective of genotypes, across these 14 studies using meta-analysis. RESULTS: The overall meta-analysis produced suggestive evidence for association at the novel IL16/STARD5/TMC3 locus on chromosome 15 (P  =  5.71 × 10(-7)). In addition, meta-analysis using the five cohorts with ≥3 FEV1 measurements per participant identified the novel ME3 locus on chromosome 11 (P  =  2.18 × 10(-8)) at genome-wide significance. Neither locus was associated with FEV1 decline in two additional cohort studies. We confirmed gene expression of IL16, STARD5, and ME3 in multiple lung tissues. Publicly available microarray data confirmed differential expression of all three genes in lung samples from COPD patients compared with controls. Irrespective of genotypes, the combined estimate for FEV1 decline was 26.9, 29.2 and 35.7 mL/year in never, former, and persistent smokers, respectively. CONCLUSIONS: In this large-scale GWAS, we identified two novel genetic loci in association with the rate of change in FEV1 that harbor candidate genes with biologically plausible functional links to lung function

Defining and measuring gender: A social determinant of health whose time has come

This paper contributes to a nascent scholarly discussion of sex and gender as determinants of health. Health is a composite of biological makeup and socioeconomic circumstances. Differences in health and illness patterns of men and women are attributable both to sex, or biology, and to gender, that is, social factors such as powerlessness, access to resources, and constrained roles. Using examples such as the greater life expectancy of women in most of the world, despite their relative social disadvantage, and the disproportionate risk of myocardial infarction amongst men, but death from MI amongst women, the independent and combined associations of sex and gender on health are explored. A model for incorporating gender into epidemiologic analyses is proposed