Objective To understand the characteristics of occupational noise hazards in key industries in Huizhou City. Methods A total of 247 enterprises from 13 key industries in Huizhou City were selected as the research subjects using the stratified judgment sampling method. The worksite survey of occupational health and workplace noise intensity and spectrum monitoring were conducted at key work sites using "questionnaires and on-site inspections" method. Results The rate of noise intensity exceeding national standards was 53.4% (132/247). The median, 25th and 75th percentile of noise pressure levels in workplaces and worksites were 85.1 (81.2, 91.2)and 82.5 (78.8, 86.3) dB(A), respectively. The high-noise workplaces accounted for 50.0% (479/958). The rate of noise intensity exceeding national standard at work sites was 32.9% (303/921). The sound pressure level of noise at work sites was positively correlated with sound pressure level of noise sources (Spearman correlation coefficient=0.73, P<0.01). The top three high-risk work sites for exceeding national noise standards were grinding, frame nailing, and material cutting, with exceedance rates of 84.6%, 81.3%, and 62.8%, respectively. The frequency characteristics of the top ten high-risk work sites were mainly high-frequency noise. There were significant differences in noise spectrum characteristics among different workpiece materials used in similar types of work sites (all P<0.05), though high-frequency noise remained dominant. Conclusion Noise hazards in workplaces of key industries in Huizhou City are relatively severe. Continuous attention should be given to key work sites with high over-standard rate, such as grinding, frame nailing, and material cutting, and noise control strategies should be developed based on frequency spectrum characteristics.

[Objective] This prospective study was conducted to assess the influence of overnight orthokeratology (OK) on low,middle and high myopia in southern Chinese teenagers.[Methods] Fifty-four subjects (107 eyes,age 11.65 ± 2.44 years,mean±SD)who matched the inclusion criteria for OK were enrolled in the study.The subjects were divided into three groups according to the different refraction baseline (low myopia group:0.75 ～ 3.00 D,51 eyes;middle myopia group:3.25 ～ 5.00 D,36 eyes;high myopia group:5.25 ～ 9.00 D,20 eyes).Refraction,central corneal thickness,corneal keratometry,anterior chamber depth and axial length (AL) were measured at baseline and after 1 years using ocular biometry.The changes were evaluated and compared among the groups.Results were analyzed by SPSS 17.0 software.[Results] Fifty-four subjects (total 107 eyes) completed the 1-year follow-up examinations.At baseline,the spherical equivalent refractive error (SER) was-2.15 D ± 0.63 D,-4.20 D ± 0.54 D,and-6.63 D ±1.18 D in three groups.The axial length was (24.50-± 0.66) mm,(25.16-± 0.65) mm,and (26.35 ± 0.87) mm in the three groups,respectively.There were no significant differences among the groups in initial central corneal thickness,anterior chamber depth,central,flat and steep kerotometry.The increase in axial length during the 1-year study period was (0.22 ± 0.27) mm,(0.09-± 0.22)mm and (0.02-± 0.22) mm in three groups,respectively,and the difference was significant between low myopia group and middle myopia group (P =0.04),low myopia group and high myopia group (P =0.008),whereas no significant difference was found between middle myopia group and high myopia group (P =0.35).Spherical equivalence decreased dramatically in three groups after one year (all P ＜ 0.0001).And the difference was significant between low myopia group and middle myopia group (P ＜ 0.0001),low myopia group and high myopia group (P ＜ 0.0001).Central,flat and steep kerotometry after one year became flatten in all group (all P ＜0.0001).There were no significant differences in the change of central corneal thickness,anterior chamber depth and corneal diameter.[Conclusions] OK lens is more effective in middle and high myopia control than in the low myopia control.The change in corneal keratometry may be one of the main factors influencing the OK treatment effect.

ObjectiveTo observe the influence of different dietary protein intake (DPI) on nitrogen balance and nutritional indices in peritoneal dialysis (PD) patients, and explore the minimal DPI to maintain nitrogen balance.MethodsThirty-four PD patients were randomly divided into group A, B and C with DPI as 1.2, 0.9 and 0.6 g·kg-1·d-1 respectively. All the patients admitted into our hospital and completed a 10-day assessment for nitrogen balance, as well as nutritional status including serum albumin (Alb), pre-albumin at baseline, the 7th and 10th day. ResultsThe DPI of group A, B and C was (1.18±0.05), (0.87±0.02), (0.66±0.03) g·kg-1·d-1, whose differences were significant (P<0.01). The dietary energy intake (DEI) was 129.29 (117.57-133.89), 111.71 (100.42-133.47), 146.86 (128.03-163.18) kJ·kg-1·d-1 respectively. Nitrogen balance was positive in group A, B, C [2.99 (2.15-4.72) g, 1.20(0.59-1.89) g, 0.24 (-0.87-1.27) g]. The BUN decreased at the 7th and 10th day (P<0.01) in group C. The BUN and phosphorus in group A increased, but without significant difference as compared to baseline. No significant differences of nutritional status were found among three groups throughout the trial. ConclusionMinimal DPI 0.65 g·kg-1·d-1 plus the supplement of protein loss in dialysate can maintain the nitrogen balance in peritoneal dialysis patients.

Objective To evaluate the expressive variety of NGF gene in injured sciatic nerves of rat. Methods For hemi-quanti- tative analysis, RT-PCR method was used in the detection of the levels of NGF mRNA in the distal stumps at 1 day and 1, 2, 4 weeks following transection of sciatic nerve. Results The 1evel of NGF mRNA was low in the normal sciatic nerve. But it was increased in the distal stump after sciatic nerve transection. The biphasic increase in NGF mRNA was characterized by a first very rapid and transient increase peaking at ist day after lesion, than a second prolonged and slow elevation starting around ist weed after lesion. Conclusion The process in NGF gene expression after sciatic nerve lesion was biphasicly increased.