Objective: To understand the relationship between eye strain and eye health behavior in college students learning at home during the period of COVID-19 epidemic, and to provide a scientific reference for improving the hygiene of using eyes among the college students. Methods: A cross sectional study and stratified cluster sampling was used to select 2 671 college students from 8 colleges in Anhui Province during the March 1st to July 1st in 2020, and an online questionnaire was survey included general information,eye strain,and daily eye health behavior. Results: The prevalence of eye strain in college students was 69.64%. Multivariable Logistic regression analysis showed that eye strain was correlated with gender, myopia, siesta habit, staying up until 2:00 am, and the use of eye liquid, with OR values(95% CI ) were 0.64(0.53-0.76), 1.77(1.42- 2.20 ),0.71(0.59-0.86), 1.39(1.17-1.65), and 2.18(1.71-2.79), respectively. There was no correlation among daily outdoor activity time, daytime reading time and the occurrence of eye strain( P >0.05). Conclusion During the period of COVID-19 epidemic, eye strain among college students is common. The daily eye health behavior is related to the occurrence of eye strain. Under the special learning context, eye care measures should be encouraged specifically.

Objective:To investigate the influencing factors and regularity of inferior mediastinal lymph node metastasis in Siewert type Ⅱ and Ⅲ adenocarcinoma of esophagogastric junction (AEG).Methods:The retrospective case-control study was conducted. The clinicopatho-logical data of 185 Siewert type Ⅱ and Ⅲ AEG patients in two medical centers (113 cases in Changzhi People's Hospital Affiliated to Changzhi Medical College and 72 cases in Heji Hospital Affiliated to Changzhi Medical College) from January 2017 to January 2022 were collected. There were 143 males and 42 females, aged (64±8)years. Patients underwent radical resection of AEG combined with inferior mediastinal lymph node dissection. Observation indicators: (1) clinicopathological charac-teristics of Siewert type Ⅱ and Ⅲ AEG patients; (2) analysis of influencing factors for inferior mediastinal lymph node metastasis in Siewert type Ⅱ and Ⅲ AEG; (3) regularity of inferior mediastinal lymph node metastasis in Siewert type Ⅱ and Ⅲ AEG. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was analyzed using the t test. Measurement data with skewed distribution were represented as M(range), and comparison between groups was analyzed using the Mann-Whitney U test. Count data were represented as absolute numbers or percentages, and comparsion between groups was analyzed using the chi-square test or Fisher exact probability. Comparison of ordinal data was analyzed using the rank sum test. Univariate and multivariate analyses were conducted using the Logistic regression model. Results:(1) Clinicopathological characteristics of Siewert type Ⅱ and Ⅲ AEG patients. Pathologic staging as stage Ⅰ, Ⅱ, Ⅲ and Ⅳ, degree of tumor invasion as stage T1, T2, T3 and T4, length of esophageal invasion ≤1 cm, >1 cm and ≤2 cm, >2 cm and ≤3 cm, >3 cm and ≤4 cm were found in 30, 61, 75, 7, 3, 41, 79, 50, 101, 46, 18, 8 cases of the Siewert type Ⅱ and Ⅲ AEG patients without inferior mediastinal lymph node metastasis, respectively, versus 0, 2, 10, 0, 0, 0, 5, 7, 4, 3, 2, 3 cases of the Siewert type Ⅱ and Ⅲ AEG patients with inferior mediastinal lymph node metastasis, showing a significant differences between them ( Z=?2.21, ?2.49, ?2.22, P<0.05). (2) Analysis of influencing factors for inferior mediastinal lymph node metastasis in Siewert type Ⅱ and Ⅲ AEG. Results of univariate analysis showed that pathological staging, depth of tumor invasion and length of esophageal invasion were related factors affecting inferior mediastinal lymph node metastasis in Siewert type Ⅱ and Ⅲ AEG ( odds ratio=2.48, 3.26, 2.03, 95% confidence intervals as 1.02?6.01, 1.21?8.80, 1.18?3.51, P<0.05). Results of multivariate analysis showed that depth of tumor invasion and length of esophageal invasion were independent influening factors affecting inferior mediastinal lymph node metastasis in Siewert type Ⅱ and Ⅲ AEG ( odds ratio=4.01, 2.26, 95% confidence interval as 1.35?11.96, 1.26?4.06, P<0.05). The inferior mediastinal lymph node metastasis probability of AEG patients with the length of esophageal invasion >3 cm and ≤4 cm was 9.47 times that of AEG patients with the length of esophageal invasion ≤1 cm. (3) Regularity of inferior mediastinal lymph node metastasis in Siewert type Ⅱ and Ⅲ AEG. The number of inferior mediastinal lymph nodes including No.110, No.111 and No.112 dissected in 185 patients of Siewert type Ⅱ and Ⅲ AEG were 127, 50 and 27. The number of lymph nodes dissected and the number of metastatic lymph nodes in No.110 and No.111 of patients with length of esophageal invasion ≤1 cm, >1 cm and ≤2 cm, >2 cm and ≤3 cm, >3 cm and ≤4 cm were 69, 4, 42, 4, 4, 1, 12, 4 and 23, 0, 17, 0, 7, 2, 3, 0, respectively. There were significant differences in metastatic lymph nodes in No.110 and No.111 of patients with length of esophageal invasion ≤1 cm, >1 cm and ≤2 cm, >2 cm and ≤3 cm, >3 cm and ≤4 cm ( χ2=8.45, 7.30, P<0.05). Of the 185 patients of Siewert type Ⅱ and Ⅲ AEG, the ratio of cases with inferior mediastinal lymph nodes metastasis was 6.49%(12/185). The ratio of inferior mediastinal lymph nodes metastasis in cases with length of esophageal invasion ≤1 cm, >1 cm and ≤2 cm, >2 cm and ≤3 cm, >3 cm and ≤4 cm were 3.81%(4/105), 6.12%(3/49), 10.00%(2/20), 27.27%(3/11), respectively. The ratio of No.110 lymph nodes metastasis in cases with length of esophageal invasion ≤1 cm, >1 cm and ≤2 cm, >2 cm and ≤3 cm, >3 cm and ≤4 cm were 2.86%(3/105), 6.12%(3/49), 5.00%(1/20), 27.27%(3/11), respectively, showing a significant difference among them ( χ2=8.26, P<0.05). Conclusions:Depth of tumor invasion and length of esophageal invasion are independent influening factors affecting inferior mediastinal lymph node metastasis in Siewert type Ⅱ and Ⅲ AEG. The rate of inferior mediastinal lymph node metastasis increases with the increase of the length of esophageal invasion.

Objective:To construct medical students' employment quality evaluation index system based on analytic hierarchy process (AHP), for providing basis to scientific and objective evaluation of medical students' employment quality.Methods:Two rounds of consultation with 21 experts were conducted to construct medical students' employment quality index and evaluation standard by Delphi method, and the weight of each index and evaluation standard determined by AHP. Excel 2007 and SPSS 21.0 were used to analyze the results of expert consultation. The enumeration data were expressed as frequency and percentage. The mean and coefficient of variation were used to describe the importance scores of experts on indicators at all levels. The positive coefficient, authority coefficient and coordination degree of experts were calculated, and the Kendall coordination coefficient ( W) test was carried out. Yaahp 6.0 is used to analyze the pairwise comparison matrix in the analytic hierarchy process to calculate the weight of the indicator. Results:The authority of expert consultation was ranged from 0.77 to 0.94, and the positive coefficient of experts was 100.00%. The evaluation system of medical students' employment quality was determined, which involved 3 first-class indexes, 9 second-class indexes and 35 third-class indexes, and the weight coefficients of each index were calculated by AHP.Conclusion:The evaluation index system of medical students' employment quality is reasonable, which can be used to provide reference standard for medical students' employment quality evaluation, and has certain application value.

In order to solve the problem of wide input range of photocurrent, aiming at the shortage of existing pulse signal acquisition system, an adaptive pulse signal acquisition system based on ADS125H02 is designed, which has high collection accuracy, low noise, anti-interference, wide input range, high integration, etc. The measurement range of the system can reach ±10 V, and the accuracy is 0.009 μV. Experimental tests show that the design of the system can extract weak pulse signals, and has good practicality.
Heart Rate

The study comprehensively puts forward several detection methods to arteriosclerosis and mainly discusses the method for pulse wave velocity (PWV for short) and ankle brachial index (ABI for short). On the basis of methods mentioned above, a portable system device for arteriosclerosis detection based on non-invasive PWV and limb blood pressure is introduced, and expectations for the subsequent engineering design and development direction are given for reference.
Ankle ; Arteriosclerosis/diagnosis* ; Blood Flow Velocity ; Blood Pressure ; Brachial Artery ; Humans ; Pulse Wave Analysis

In order to comprehensively evaluate the human body's functions of breathing, heart function and circulation metabolism under controlled conditions to diagnose respiratory and cardiac functions, a cardiopulmonary exercise test (CPET) system was developed. The system is divided into two parts:hardware and software. The hardware part includes measurement of six life information monitoring signals such as 12-lead ECG, respiratory mechanics, blood pressure, blood oxygen, carbon dioxide and oxygen. The software part realizes waveform display, storage and playback, et al. The experimental results show that the system is safe and reliable which provides reliable measurement parameters for evaluating human respiratory, cardiac function, circulation, metabolism and other functions. It has a good application prospect.
Electrocardiography ; Exercise Test ; Heart ; Heart Rate ; Humans ; Oxygen

This article describes the design of a portable blood oxygen simulation system that can be used to simulate various blood gas saturation states of the human body. The system can be used to simulate various states of blood gas saturation, and can also simulate large blood oxygen saturation dynamic range, pulse rate range and perfusion index range. It can be used for testing, but not for clinical examination instruments. Moreover, the system has the characteristics of small size and low cost compared with the commercial blood oxygen simulator. Although the simulation system is not directly used for the detection of blood gas saturation of patients, it is also an essential equipment in the production and testing process, so it has certain practical value.
Heart Rate ; Humans ; Oximetry ; instrumentation ; Oxygen ; analysis

Objective:To investigate the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients with maintenance hemodialysis (MHD) in Jiangsu province during SARS-CoV-2 pandemic in China from December 7, 2022 to January 27, 2023, and to analyze the influencing factors of all-cause death.Methods:It was a multi-center cross-sectional investigation. Structured questionnaire was used to collect patient information by medical staff of each hemodialysis center (room) as investigators. Part of the demography data and laboratory examination data came from the Jiangsu Province Hemodialysis Data Information System. MHD patients from hemodialysis centers (rooms) at all levels of medical institutions and independent hemodialysis institutions in Jiangsu province during the outbreak of SARS-CoV-2 infection were included, and the clinical characteristics and all-cause mortality of confirmed and suspected cases of SARS-CoV-2 infection were analyzed.Results:Questionnaire surveys and data analysis on 57 278 patients in 407 hemodialysis centers (rooms) were completed, accounting for 90.41% of the total number of MHD patients (63 357 cases) in Jiangsu province during the same period. There were 24 038 cases (41.97%) of SARS-CoV-2 infection and 14 805 cases (25.85%) of suspected infection, which were widely distributed in all dialysis centers in Jiangsu province. After clinical classification of 38 843 confirmed and suspected SARS-CoV-2 infection cases, 3 662 cases were severe and critical cases, accounting for 9.43% of the infected and suspected cases. Among the patients who had completed the questionnaires, there were 1 812 all-cause deaths, with an all-cause mortality rate of 3.16%. Multivariate logistic regression analysis showed that elderly (taking ≤50 years as a reference, 51-59 years: OR=1.583, 95% CI 1.279-1.933, P=0.001; 60-69 years: OR=3.972, 95% CI 3.271-4.858, P<0.001; 70-79 years: OR=7.236, 95% CI 5.917-8.698, P<0.001; ≥80 years: OR=11.738, 95% CI 9.459-14.663, P<0.001), male ( OR=1.371, 95% CI 1.229-1.529, P<0.001), and co-infection with hepatitis B virus (HBV) (positive serum HBV surface antigen, OR=0.629, 95% CI 0.484-0.817, P<0.001) were independent influencing factors for all cause mortality. Receiver-operating characteristic curve analysis showed that the area under the curve for male, age and current HBV infection prediction of all-cause death was 0.529 ( P<0.001), 0.724 ( P<0.001) and 0.514 ( P=0.042), respectively, and the cut-off value for age prediction of all-cause death was 65.5 years old. Compared with patients without HBV infection, MHD patients with HBV infection significantly reduced the proportion of severe and critically ill patients, all-cause hospitalizations and all cause deaths when infected with SARS-CoV-2 (4.99% vs. 6.41%, χ2=6.136, P=0.013; 8.90% vs. 11.44%, χ2=11.662, P<0.001; 2.01% vs. 3.37%, χ2=10.713, P=0.001, respectively). Conclusion:The MHD patients in Jiangsu province are susceptible to SARS-CoV-2. Elderly age and male gender are independent risk factors for death in MHD patients during the epidemic, while the HBV infection may be a protective factor for death of MHD patients infected with SARS-CoV-2.