Search

Abstract Background Mutations in the GJB2 gene are the most common cause of nonsyndromic recessive hearing loss in China. In about 6% of Chinese patients with severe to profound sensorineural hearing impairment, only monoallelic GJB2 mutations known to be either recessive or of unclear pathogenicity have been identified. This paper reports the prevalence of the GJB2 IVS1+1G>A mutation in a population of Chinese hearing loss patients with monoallelic pathogenic mutation in the coding region of GJB2. Methods Two hundred and twelve patients, screened from 7133 cases of nonsyndromic hearing loss in China, with monoallelic mutation (mainly frameshift and nonsense mutation) in the coding region of GJB2 were examined for the GJB2 IVS1+1G>A mutation and mutations in the promoter region of this gene. Two hundred and sixty-two nonsyndromic hearing loss patients without GJB2 mutation and 105 controls with normal hearing were also tested for the GJB2 IVS1+1G>A mutation by sequencing. Results Four patients with monoallelic mutation in the coding region of GJB2 were found carrying the GJB2 IVS1+1G>A mutation on the opposite allele. One patient with the GJB2 c.235delC mutation carried one variant, -3175 C>T, in exon 1 of GJB2. Neither GJB2 IVS1+1G>A mutation nor any variant in exon 1 of GJB2 was found in the 262 nonsyndromic hearing loss patients without GJB2 mutation or in the 105 normal hearing controls. Conclusion Testing for the GJB2 IVS 1+1 G to A mutation explained deafness in 1.89% of Chinese GJB2 monoallelic patients, and it should be included in routine testing of patients with GJB2 monoallelic pathogenic mutation.

In order to strictly control the solid impurity particles of the pipeline and ensure the cleanliness of the pipeline of the gas supply system, a filter is installed on the pipeline before the inlet of the equipment to ensure the normal operation of the pipeline instrumentation and compressors. Since the flow of the fluid will impact the filter screen, the impact stress of the fluid on the filter screen is worth studying. However, the structure of the filter screen is complicated, so the filter screen is simplified for research. The present study adopts the dimensionless π theorem to make the density, viscosity, flow velocity, and other factors of a gas-phase fluid and solid-phase fluid dimensionless and obtains an expression for the stress acting on a filter screen as a function of the fluid parameters. Then the numerical simulation is carried out using the finite element analysis software Fluent. By changing only the velocity of the fluid and changing only the mass flow rate of the solid impurity particles, numerical simulations show that the stress acting on the filter screen has a quadratic relation with the fluid flow velocity, the stress acting on the filter screen has a linear relation with the mass flow of the solid-phase fluid, which is consistent with the law embodied in the formula derived from the π theorem. In addition, by comparing the stress acting on the filter screen traversed by different gas phase fluid media (i.e. air, CH4, and N2) under the same fluid flow conditions, it is found that effects of stress acting on the filter screen caused by different gas phase-fluids are different. All these results agree with theoretical predictions. These laws can play a guiding role in practical engineering applications in the future. Highlights Based on the dimensionless π theory, the expression about the stress of the strainer is derived. A simplified finite element model of partial filter screen is established. Using the finite element analysis software, the stress of the filter screen is obtained by changing the flow velocity of the fluid, the mass flow of the solid impurity particles and the different gas phase fluids. The filter screen can be protected from damage by controlling the flow parameters of the fluid. [ABSTRACT FROM AUTHOR]

Purpose: Our purpose was to investigate the relationship between intake of excess free fructose beverages and allergy among children and adolescents.Methods: We analyzed data of 860 children (aged 6 to 12 years) and 1,142 adolescents (aged 13 to 19 years) from the National Health and Nutrition Examination Survey 2005-2006. Logistic regression analyses were performed to determine the associations between consumption of excess free fructose beverages and allergic symptoms or allergic sensitization.Results: The pattern of findings was not entirely consistent, but some analyses supported the hypothesis of an association between intake of excess free fructose beverages and allergy. After controlling for the potential confounders, children who consumed nondiet fruit drinks at least 5 times per week had a nearly 2.5-fold greater odds of allergic sensitization than did those who consumed such drinks only 1 to 3 times per month (OR = 2.446; 95% CI, 1.583-3.780). Adolescents who consumed excess free fructose beverages at least 5 times per week or 1 to 4 times per week had about fivefold greater odds of presence of allergic symptoms than did those who seldom consumed these beverages (OR = 5.164; 95% CI, 1.866-14.297 and OR = 4.112; 95% CI, 1.857-9.107, respectively). Adolescents who consumed apple juice at least 5 times per week had a twofold greater odds of presence of allergic sensitization than did the seldom consumers (OR = 2.215; 95% CI, 1.178-4.164).Conclusions: These findings provide some support for the hypothesis of a link between intake of excess free fructose beverages and allergic symptoms or allergic sensitization in children and adolescents. [ABSTRACT FROM AUTHOR]