Distribution of IOP and its relationship with refractive error and other factors:the Anyang University Students Eye Study

AIM:To investigate the distribution of intraocular pressure(IOP)and its relationship with refractive error and other factors in university students from Anyang,China.METHODS:A university-based study was conducted.Subjects were invited to complete ophthalmic examinations,including visual acuity,noncontact tonometr y(NCT),cycloplegic autorefraction,and ocular biometry.Univariable and multivariable analyses were used to evaluate the associations between IOP and other factors.Only data from right eyes were used in analysis.RESULTS:A total of 7720 subjects aged 16 to 26 years old were included,and 2834(36.4%)of the participants were male.The mean IOP of the right eye for all subjects was 15.52±3.20 mm Hg(95%CI:15.45,15.59).Using multivariate linear regression analysis,IOP was found to correlate significantly with younger age(P<0.001;standardized regression coefficientβ,-0.061;regression coefficientβ,-0.139;95%CI:-0.18,-0.09),higher myopic refractive error(P=0.044;standardizedβ,-0.060;regression coefficientβ,-0.770;95%CI:-0.15,-0.002),higher central corneal thickness(P<0.001;standardizedβ,0.450;regression coefficientβ,0.044;95%CI:0.04,0.05),and shorter axial length(AL;P<0.001;standardizedβ,-0.061;regression coefficientβ,-0.163;95%CI:-0.25,-0.07).CONCLUSION:This study described the normal distribution of IOP.In Chinese university students aged 16-26 y,higherIOP is associated with younger age,higher myopic refractive error,higher thickness of the central cornea,and shorter AL.

Experimental-based study of gear vibration characteristics incorporating the fractal topography of tooth surface

Microscopic roughness is inevitable on the gear meshing surface,which is also a key parameter affecting the dynamic response.The surface roughness exhibits self‐affine characteristics across multiscales.To explore the influence of surface fractal topography on the vibration amplitude of the gear system under different rotational speeds and loads,an experimental setup of spur gear transmission is devised.The fractal dimension and fractal roughness of the meshing surface are calculated by the power spectral density method.The relationships between gear response and fractal parameters are revealed experimentally.Results indicate that a rougher tooth surface,that is,a smaller fractal dimension or larger fractal roughness,corresponds to an intense vibration amplitude.The sensitivity of dynamic response to the tooth surface topography varies at different rotational speeds and loads.Under low speed and light load conditions,the fractal dimension and fractal roughness have a more obvious influence on the dynamic response of the gear transmission system.With the increase of speed and load,the macroworking conditions gradually become the main factor attributed to vibration amplitude.

New loci for refractive errors and ocular biometric parameters in young Chinese Han adults

Myopia has become a major public health issue with an increasing prevalence.There are still individuals who experience similar environmental risk factors and,yet,remain non-myopic.Thus,there might be genetic factors protecting people from myopia.Considering the opposite ocular characteristics of primary angle closure glaucoma(PACG)to myopia and possible common pathway between them,we propose that certain risk genes for PACG might act as a protective factor for myopia.In this study,2,678 young adults were genotyped for 37 targeted single nucleotide polymorphisms.Compared with emmetropia,rs1401999(allele C:OR=0.795,P=0.03;genotype in dominant model:OR=0.759,P=0.02)and rs1258267(allele A:OR=0.824,P=0.03;genotype in dominant model:OR=0.603,P=0.01)were associated with low to moderate myopia and high myopia,respectively.Genotype under recessive model of rs11024102 was correlated with myopia(OR=1.456,P=0.01),low to moderate myopia(OR=1.443,P=0.02)and high myopia(OR=1.453,P=0.02).However,these associations did not survive Bonferroni correction.Moreover,rs1401999,rs1258267,and rs11024102 showed associations with certain ocular biometric parameters in different groups.Our study suggests that ABCC5,CHAT and PLEKHA7 might be associated with refractive errors by contributing to the regulation of ocular biometry,in terms of uncorrected results and their biological functions.

Fractal-based dynamic response of a pair of spur gears considering microscopic surface morphology

The meshing surfaces of a gear pair are rough from a microscopic perspective and the surface topography will affect the dynamic response.To study the influence of real surface topography on the gear system dynamic performance,this paper es-tablishes a 3-degree of freedom transverse-torsional dynamic model with regard to the morphology of the interface.By fractal theory,the expression of backlash be-tween gears is modified based on the height of asperities.The time-varying sifness is calculated according to the fractal method rather than assuming a constant,which is more realistic.The dimensionless dynamic differ ential equations are established and solved with surface topography affected backlash function and time-varying sifess.The dynamic response of the gear system with respec to fractal dimension and fractal roughness is analyzed.