Objective To investigate the current situation and health effects of indoor microbial pollution in Xi&#39;an, to analyze the purification effect of air purifiers on indoor microbial pollution, and to provide reference for improving the indoor environment. Methods Through stratified random sampling, 20 families from rural areas and 20 families from upwind and downwind urban areas respectively were selected from Xi&#39;an. Data was collected by questionnaire surveys and on-site environmental sampling. Non-parametric analysis and correlation analysis were used for statistical analysis. Results Overall, the standard-exceeding rate of total count of bacteria was 5.00%. The medians of the total count of bacteria and fungi were 312.50 cfu/m3 and 260.00 cfu/m³, respectively. In terms of health effects, the correlation between rhinitis and cold with total bacterial count was statistically significant (P<0.05), with the correlation coefficients of 0.182 and 0.223, respectively. Purification effect of air purifiers on microbial pollution was statistically significant (P<0.05). After opening for 2 hours, the total numbers of bacteria and fungi decreased significantly. Conclusion The occurrence risk of colds and rhinitis is increased by indoor microbial pollution. Air purifiers have a certain effect on decreasing the total number of bacteria and fungi. It is recommended to use air purifiers with high CADR of particulate matter, double-layer filter and sterilization and dehumidification function, and replace the filters regularly to reduce indoor microbiological contamination.

Objective: To investigate the effects of retinoid-related orphan receptor γ (RORγ) gene on proliferation and metastasis of human colon cancer cells． Methods: RORγ knockdown cell lines were constructed and the knockdown efficiency was detected by RT-qPCR and Western blot assays ; MTT，colony formation，Transwell and wound healing assays were used to detect cell proliferation and metastasis ; the expression of epithelial-mesenchymal transition (EMT) related proteins was detected by Western blot．The relationship between RORγ gene expression and immune cell infiltration in tumor microenvironment was analyzed using TIMER 2. 0 database. Results : The knockdown of RORγ enhanced the viability (F = 157. 40，P＜0. 01) ，clonogenesis (F = 61. 35，P＜0. 01) ，migration (F = 13. 00，P＜0. 01) ，invasion (F = 21. 26，P＜0. 01) and wound healing ability (F = 877. 2，P＜0. 01) of colon cancer cells，inhibited the expression of E-Cadherin，and promoted the expression of vimentin and N-Cadherin．TIMER 2. 0 database analysis showed that RORγ expression in colon adenocarcinoma ( COAD) tissues was associated with multiple immune cell infiltrates． Conclusion Downregulation of RORγ expression promoted the proliferation and metastasis of colon cancer cells.

AIM: To analyze the risk factors of corneal epithelial dysfunction(CED)after pars plana vitrectomy(PPV).

METHODS: Clinical data of 235 patients with 235 eyes of PPV from July 2016 to June 2018 in our hospital were retrospectively analyzed. The age, sex and related medical history of the patients(such as ocular lesions and systemic diseases)were collected, and the intraocular fillers, operation time, postoperative intraocular pressure were recorded. Logistic regression was used to analyze the risk factors of CED after PPV.

RESULTS: The incidence of CED after PPV was 16.6%(39/235), and the incidence of persistent corneal epithelial lesion was 1.3%(3/235). Logistic regression showed that age, preoperative xerophthalmia, diabetes mellitus, Silicone oil filling, postoperative high intraocular pressure and operation time were risk factors for CED after PPV. The OR values were 1.270, 5.218, 18.598, 4.659, 10.799 and 1.104, respectively.

CONCLUSION: Age, preoperative xerophthalmia, diabetes mellitus, silicone oil filling, postoperative high intraocular pressure and operation time are risk factors for CED after PPV.

AIM:To observe, analyze and compare the effect of minimally external surgery under microscopy and traditional external surgery on the treatment of non-complicated rhegmatogenous retinal detachment.

METHODS:The clinical data of 53 patients with 53 eyes of non-complicated rhegmatogenous retinal detachment in our hospital was analyzed retrospectively, of which the minimally external retinal detachment surgery under microscopy was performed in 25 patients with 25 eyes of non-complicated rhegmatogenous retinal detachment(the research group), and the traditional external retinal detachment surgery was performed in 28 patients with 28 eyes of non-complicated rhegmatogenous retinal detachment(the control group). All surgeries were performed by the same surgeon, and the clinical efficacy and complications of the two groups were compared and analyzed.

RESULTS: In postoperative hole closure, there was no significant difference in the primary rate of reattachment of the retina between the two groups(P>0.05). There was a statistically significant difference in postoperative complications between the two groups(P<0.05). The best corrected visual acuity after surgery was better than that before surgery in both groups. There was no significant difference in the increase of postoperative visual acuity between the two groups(P>0.05). There was a statistically significant difference in operative time between the two groups(P<0.05).

CONCLUSION: The effect of minimally external retinal surgery under microscopy and traditional external retinal surgery is similar in the treatment of non-complicated rhegmatogenous retinal detachment, but the minimally external retinal surgery has the advantages of shorter time, less damage and fewer complications.