Objective: To investigate the status of heat illness, knowledge awareness and adaptive behaviors of heat wave knowledge among food delivery riders, so as to provide a basis for optimizing heat wave response measures for food delivery riders. Methods: In November 2022, food delivery riders from a large food delivery platform in Ningbo City, Zhejiang Province were selected as survey subjects using a cluster sampling method. A self-designed electronic questionnaire was used to select demographic information, work status, lifestyle behaviors and disease history, heat illness status, knowledge awareness and adaptive behaviors of heatwave. Results: A total of 911 questionnaires were distributed, and 830 valid questionnaires were recovered, resulting in a valid response rate of 91.11%. Among the respondents, 796 (95.90%) were male, and 818 (98.55%) worked full-time. The mean age was (27.75±8.00) years. A total of 470 respondents (56.63%) had a work tenure of less than 1 year. The primary working hours were 8-<12 hours, with 504 people accounting for 60.72%. There were 108 cases of heatstroke, with an occurrence rate of 13.01%. And 286 people reported heat-related symptoms, with an occurrence rate of 34.46%. The overall awareness rate of heat wave knowledge was 73.22%, while the awareness rate of heat warning signal classification was relatively low at 9.04%. The heat wave cognition score was (5.86±1.31) points. There were statistically significant differences in heat wave cognition scores among food delivery riders of different ages, educational levels, family annual income, work tenures, and work durations (all P<0.05). Regarding positive adaptive behaviors, the number of riders paying attention to weather forecasts and actively learning about preventive measures was higher (734 people each, accounting for 88.43%). Regarding negative adaptive behaviors, the number of riders who often drank ice-cold beverages was higher (509 people, accounting for 61.33%). The heat wave adaptive behavior score was (6.88±1.77) points. There were statistically significant differences in adaptive behavior scores among riders with different educational levels, family annual income, work tenures, and smoking frequency (all P<0.05). Conclusions The occurrence rates of heatstroke and heat-related symptoms among food delivery riders are relatively high. The knowledge awareness and adaptive behaviors regarding heat wave are at a moderate level. It is suggested to strengthen health education, reinforce risk cognition of heat wave, and promote positive adaptive behaviors among food delivery riders.

Objective:To explore the protocol for handgrip exercise stress echocardiography by comparing different maximal voluntary contraction（MVC）handgrip groups with bicycle exercise stress.Methods:Forty-one healthy volunteers were enrolled prospectively from June to October 2024 in Tangdu Hospital and utilized a color Doppler echocardiography system，supine cycle ergometer，and handgrip dynamometer to collect echocardiographic data at baseline，during handgrip exercises at 20%（3 min），30%（3 min），and 40%（2 min）of MVC，and spine bicycle exercise stress at peak. Parameters measured included left ventricular ejection fraction（EF），stroke volume（SV），cardiac output（CO），mitral inflow E-wave and A-wave velocities，lateral and septal mitral annular e' velocities，E/A and E/e' ratios，global longitudinal strain（GLS），left atrial reservoir strain（LAS R），conduit strain（LAS CD），and contractile strain（LAS CT）. The non-invasive myocardial work indices were also assessed，including global work index（GWI），global constructive work（GCW），global wasted work（GWW），and global work efficiency（GWE）. Statistical analyses were performed using repeated measures analysis of variance，with corrected paired t-test for comparisons between two exercise stress states. Results:Compared with the baseline state，heart rate，blood pressure，CO、GWI、GCW、GWW and LAS CT gradually increased，while EF、E/A、GLS、GWE、LAS R and LAS CD gradually decreased under 20%，30% and 40% of MVC states. The changes were most obvious at 40% of MVC state，which was selected for the handgrip exercise stress echocardiography protocol.Compared with the peak of bicycle exercise，at 40% of MVC，heart rate was significantly lower［（81.2 ± 9.7）bpm vs.（164.6 ± 11.3）bpm， P<0.05）］，systolic blood pressure was slightly lower［（152.9 ± 13.2）mmHg vs.（165.1 ± 20.4）mmHg， P<0.05］，diastolic blood pressure was higher［（96.0 ± 9.5）mmHg vs.（89.5 ± 10.9）mmHg， P<0.05］，GLS was lower［（19.1 ± 1.5）% vs.（23.5 ± 1.7）%， P<0.05］，GWI was similar［（2 254.2 ± 417.3）mmHg% vs.（2 227.5 ± 389.0）mmHg%， P>0.05］，but GWE was higher［（95.3 ± 2.0）% vs.（93.7 ± 2.0）%， P<0.05］，and LAS R was lower［（39.4 ± 4.2）% vs.（43.9 ± 4.1）%， P<0.05］. Conclusions:The 40% of MVC lasting 2 min can cause the most significant handgrip-related changes in cardiac function and can be used as the standard protocol for handgrip exercise stress echocardiography. Handgrip stress exercise can cause significant changes in cardiac systole，diastole，and work performance，showing different characteristics compared with bicycle exercise stress.

Objective:To investigate the impact of different luteal phase support protocols on pregnancy outcomes in patients aged ≤35 years undergoing modified natural cycle frozen-thawed embryo transfer (mNC-FET).Methods:A retrospective cohort study was conducted to analyze 2 086 cycles of patients aged ≤35 years who received mNC-FET cycles in Reproductive Health Hospital of the Third Affiliated Hospital of Zhengzhou University from January 2018 to December 2020. The cycles were divided into three groups based on luteal phase support protocols used. The patients received a combination of progesterone soft capsule and dydrogesterone in the group A (446 cycles), the patients received dydrogesterone in the group B (439 cycles), and the patients received a combination of progesterone vaginal sustained-release gel and dydrogesterone in the group C (1 201 cycles). The pregnancy and perinatal outcomes were compared between groups A and B, groups C and B after matching the baseline data in a ratio of 1∶1 using the propensity score matching (PSM). The effect of different luteal phase support on live birth rate was analyzed after adjusting for confounding factors affected by univariate and multivariate generalized estimating equation (GEE).Results:After PSM, there were no significant differences between groups A and B, groups C and B in human chorionic gonadotropin positive rate, clinical pregnancy rate, ectopic pregnancy rate, live birth rate in transplant cycle, incidence of low weight, macrosomia, premature delivery rate, pregnancy complication rate and incidence of birth defects (all P>0.05). GEE analysis showed that three different luteal phase support regimens were not associated with live birth rate. Conclusion:In the mNC-FET cycle, patients aged ≤35 years who chose dydrogesterone alone as luteal phase support drug, had no difference in live birth rate and perinatal outcome between progesterone soft capsules or progesterone vaginal sustained-release gel combined with dydrogesterone, but the outcome still needs to be confirmed by large sample prospective studies.

Objective:To investigate the impact of different luteal phase support protocols on pregnancy outcomes in patients aged ≤35 years undergoing modified natural cycle frozen-thawed embryo transfer (mNC-FET).Methods:A retrospective cohort study was conducted to analyze 2 086 cycles of patients aged ≤35 years who received mNC-FET cycles in Reproductive Health Hospital of the Third Affiliated Hospital of Zhengzhou University from January 2018 to December 2020. The cycles were divided into three groups based on luteal phase support protocols used. The patients received a combination of progesterone soft capsule and dydrogesterone in the group A (446 cycles), the patients received dydrogesterone in the group B (439 cycles), and the patients received a combination of progesterone vaginal sustained-release gel and dydrogesterone in the group C (1 201 cycles). The pregnancy and perinatal outcomes were compared between groups A and B, groups C and B after matching the baseline data in a ratio of 1∶1 using the propensity score matching (PSM). The effect of different luteal phase support on live birth rate was analyzed after adjusting for confounding factors affected by univariate and multivariate generalized estimating equation (GEE).Results:After PSM, there were no significant differences between groups A and B, groups C and B in human chorionic gonadotropin positive rate, clinical pregnancy rate, ectopic pregnancy rate, live birth rate in transplant cycle, incidence of low weight, macrosomia, premature delivery rate, pregnancy complication rate and incidence of birth defects (all P>0.05). GEE analysis showed that three different luteal phase support regimens were not associated with live birth rate. Conclusion:In the mNC-FET cycle, patients aged ≤35 years who chose dydrogesterone alone as luteal phase support drug, had no difference in live birth rate and perinatal outcome between progesterone soft capsules or progesterone vaginal sustained-release gel combined with dydrogesterone, but the outcome still needs to be confirmed by large sample prospective studies.

Objective:To explore the protocol for handgrip exercise stress echocardiography by comparing different maximal voluntary contraction（MVC）handgrip groups with bicycle exercise stress.Methods:Forty-one healthy volunteers were enrolled prospectively from June to October 2024 in Tangdu Hospital and utilized a color Doppler echocardiography system，supine cycle ergometer，and handgrip dynamometer to collect echocardiographic data at baseline，during handgrip exercises at 20%（3 min），30%（3 min），and 40%（2 min）of MVC，and spine bicycle exercise stress at peak. Parameters measured included left ventricular ejection fraction（EF），stroke volume（SV），cardiac output（CO），mitral inflow E-wave and A-wave velocities，lateral and septal mitral annular e' velocities，E/A and E/e' ratios，global longitudinal strain（GLS），left atrial reservoir strain（LAS R），conduit strain（LAS CD），and contractile strain（LAS CT）. The non-invasive myocardial work indices were also assessed，including global work index（GWI），global constructive work（GCW），global wasted work（GWW），and global work efficiency（GWE）. Statistical analyses were performed using repeated measures analysis of variance，with corrected paired t-test for comparisons between two exercise stress states. Results:Compared with the baseline state，heart rate，blood pressure，CO、GWI、GCW、GWW and LAS CT gradually increased，while EF、E/A、GLS、GWE、LAS R and LAS CD gradually decreased under 20%，30% and 40% of MVC states. The changes were most obvious at 40% of MVC state，which was selected for the handgrip exercise stress echocardiography protocol.Compared with the peak of bicycle exercise，at 40% of MVC，heart rate was significantly lower［（81.2 ± 9.7）bpm vs.（164.6 ± 11.3）bpm， P<0.05）］，systolic blood pressure was slightly lower［（152.9 ± 13.2）mmHg vs.（165.1 ± 20.4）mmHg， P<0.05］，diastolic blood pressure was higher［（96.0 ± 9.5）mmHg vs.（89.5 ± 10.9）mmHg， P<0.05］，GLS was lower［（19.1 ± 1.5）% vs.（23.5 ± 1.7）%， P<0.05］，GWI was similar［（2 254.2 ± 417.3）mmHg% vs.（2 227.5 ± 389.0）mmHg%， P>0.05］，but GWE was higher［（95.3 ± 2.0）% vs.（93.7 ± 2.0）%， P<0.05］，and LAS R was lower［（39.4 ± 4.2）% vs.（43.9 ± 4.1）%， P<0.05］. Conclusions:The 40% of MVC lasting 2 min can cause the most significant handgrip-related changes in cardiac function and can be used as the standard protocol for handgrip exercise stress echocardiography. Handgrip stress exercise can cause significant changes in cardiac systole，diastole，and work performance，showing different characteristics compared with bicycle exercise stress.

Objective:To investigate the clinical applicability of the four-grade grading(G4) advocated by the academy in recent years compared with the guideline-recommended three-grade grading(G3) in functional tricuspid regurgitation (FTR).Methods:A total of 137 consecutive patients were prospectively included from outpatient and inpatient clinics at Tangdu Hospital, Air Force Medical University from May to December 2023. All patients underwent echocardiography and were graded for regurgitation based on the 2017 American Society of Echocardiography Valve Evaluation Guidelines as the reference standard. The patients with regurgitation were grouped according to the G3 based on the guidelines and the G4 advocated by the academic community in recent years, respectively. The consistency of the regurgitation grading between multi-indicators and single-indicators was analyzed using the Kappa test for both G3 and G4. The quantitative regurgitation relevant parameters were analyzed using ROC curves to evaluate the diagnostic efficacies for G4, including the vena contracta width (VCW), the area of the color flow jet (A Jet), and the radius of the PISA (R PISA). Results:The results of consistency analysis showed that the consistency of regurgitation volume (RVol) was significantly higher in the G4 multi-indicators comprehensive assessment versus the single-indicators assessment compared with the G3, with a Kappa value of 0.84 vs. 0.30. The consistency of effective regurgitant orifice area (EROA) and VCW remained unchanged, with a Kappa value of 0.76 vs. 0.89, 0.51 vs. 0.66. ROC curve analysis showed that for the G4, the area under the curve (AUC) for moderate regurgitation were 0.854, 0.993, and 0.894, respectively, while for moderate-severe regurgitation, these values were 0.899, 0.979, and 0.917, respectively.Conclusions:For FTR, the G4 currently advocated by the academic community has better consistency between single-indicators and comprehensive indicators grading than the G3 based on the guideline, which is clinically applicable; A Jet, R PISA, and VCW can be supplemented to the G4, which helps to improve the quantitative assessment system.

Objective: To evaluate the health risk of drinking water in Ningbo City, Zhejiang Province from 2021 to 2022, so as to provide insights into ensuring the safety of drinking water. Methods: The monitoring data of drinking water from 2021 to 2022 in Ningbo City were collected from the Chinese Disease Prevention and Control Information System. The routine indicators and disinfectant indicators (radioactivity indicators were excluded) of drinking water were evaluated according to the reference limits issued by Standards for Drinking Water Quality (GB 5749-2006), and the qualification rates were calculated. The indicators with detection rate higher than 50% were selected, and assessed the carcinogenic and non-carcinogenic risks via drinking water using the risk assessment model recommended by the United States Environmental Protection Agency. Results: A total of 1 678 samples were monitored in Ningbo City from 2021 to 2022. Sodium hypochlorite was the main disinfectant among 1 558 samples from centralized water supply (1 079 samples, 64.30%), and none of the 120 samples from decentralized water supply underwent disinfection treatment. The qualification rate of 88.38%, and the pollutants with a detection rate higher than 50% were nitrate, fluoride, trichloromethane and aluminum. The median carcinogenic risk value of trichloromethane was 2.964×10-6 (interquartile range, 3.909×10-6), and the median hazard quotient values of nitrate, fluoride, trichloromethane and aluminum were 1.631×10-2 (interquartile range, 1.361×10-2), 3.955×10-2 (3.164×10-2), 2.231×10-2 (2.942×10-2) and 2.136×10-4 (6.573×10-4), respectively. Conclusion The carcinogenic and non-carcinogenic risks through drinking water for 17 pollutants in drinking water of Ningbo City from 2021 to 2022 were at low levels.

Objective:To explore the effect of case study combined with scenario simulation in teaching clinical internship of radiation oncology.Methods:This study selected 144 undergraduate students majoring in clinical medicine who interned at the Department of Radiotherapy at Sun Yat-sen University Cancer Center from November 2022 to May 2023 as the research subjects. They were randomly divided into a control group and an observation group. The control group received traditional teaching, while the observation group received case study combined with scenario simulation teaching, with 72 students in each group. The two groups of trainees were evaluated for theoretical and skill assessment scores, core competencies, and teaching satisfaction. The t-test and chi-square test were performed using SPSS 22.0. Results:The theoretical and skill scores of the trainees in the observation group [(88.27±3.40) and (92.69±3.65)] were higher than those in the control group [(83.01±10.38) and (87.20±3.74)], and the differences were statistically significant. Compared with the control group, the observation group showed higher core competency scores in eight dimensions, including learning initiative and enthusiasm, knowledge comprehension ability, critical thinking ability, clinical specialty practice ability, analytical and problem-solving ability, doctor-patient communication, professional ethics, and teamwork ability, and the differences were statistically significant ( P<0.05). The satisfaction scores of the observation group trainees of teaching plan, teaching content, teaching methods, teaching results, and teaching ability were higher than those of the control group, and the differences were statistically significant ( P<0.05). Conclusions:The application of case study combined with scenario simulation teaching clinical internship of radiation oncology can help improve the theoretical and skill scores of medical students, as well as their core competencies and teaching satisfaction. This is a teaching method worthy of application and promotion.

Objective:To explore the effect of case study combined with scenario simulation in teaching clinical internship of radiation oncology.Methods:This study selected 144 undergraduate students majoring in clinical medicine who interned at the Department of Radiotherapy at Sun Yat-sen University Cancer Center from November 2022 to May 2023 as the research subjects. They were randomly divided into a control group and an observation group. The control group received traditional teaching, while the observation group received case study combined with scenario simulation teaching, with 72 students in each group. The two groups of trainees were evaluated for theoretical and skill assessment scores, core competencies, and teaching satisfaction. The t-test and chi-square test were performed using SPSS 22.0. Results:The theoretical and skill scores of the trainees in the observation group [(88.27±3.40) and (92.69±3.65)] were higher than those in the control group [(83.01±10.38) and (87.20±3.74)], and the differences were statistically significant. Compared with the control group, the observation group showed higher core competency scores in eight dimensions, including learning initiative and enthusiasm, knowledge comprehension ability, critical thinking ability, clinical specialty practice ability, analytical and problem-solving ability, doctor-patient communication, professional ethics, and teamwork ability, and the differences were statistically significant ( P<0.05). The satisfaction scores of the observation group trainees of teaching plan, teaching content, teaching methods, teaching results, and teaching ability were higher than those of the control group, and the differences were statistically significant ( P<0.05). Conclusions:The application of case study combined with scenario simulation teaching clinical internship of radiation oncology can help improve the theoretical and skill scores of medical students, as well as their core competencies and teaching satisfaction. This is a teaching method worthy of application and promotion.

Objective:To study the incidences of complications in twins with birth weight discordance (BWD) during hospitalization.Methods:From January 2011 to December 2020, twins born in the Department of Obstetrics and hospitalized in NICU of our hospital were retrospectively studied. Twins with BWD>15% were assigned into BWDT group and BWD≤15% into twins with birth weight concordant (BWCT) group. Complications during hospitalization were compared between the two groups.Results:A total of 1 546 pairs of twins were enrolled, including 486 (31.4%) in BWDT group and 1 060 (68.6%) in BWCT group. Compared with BWCT group, BWDT group had significantly higher incidences of pulmonary surfactant (PS) utilization (47.7% vs. 42.2%), continuous positive airway pressure ≥ 24 h (40.5% vs. 35.0%), high-flow nasal cannula ≥ 24 h (22.8% vs. 16.3%), neonatal respiratory distress syndrome (52.9% vs. 47.1%), bronchopulmonary dysplasia (BPD) (15.6% vs. 11.1%), persistent pulmonary hypertension of the newborn (3.1% vs. 1.4%) and anemia (79.6% vs. 70.1%) (all P<0.05). After adjusting for confounding factors, the risks of pulmonary hemorrhage ( OR=2.036, 95% CI 1.119-3.703, P=0.020) and BPD ( OR=2.960, 95% CI 1.656-5.219, P=0.010) in BWDT group were higher than BWCT group. Conclusions:BWD twins has higher incidences of complications during hospitalization than BWC twins.