Background Atherosclerotic cardiovascular disease (ASCVD) is a major contributor to the global burden of cardiovascular diseases. However, evidence from meta-analyses on the association between ambient ozone exposure and ASCVD risk remains relatively insufficient. Objective To explore the epidemiological association between ambient ozone exposure and ASCVD, providing scientific evidence for ASCVD prevention and control from the perspective of environmental risk factor management. Methods We systematically searched PubMed, Web of Science, Embase, the Cochrane Library, CNKI, Wanfang Database, CBM, and VIP for published epidemiological studies on the relationship between ambient ozone exposure and ASCVD from January 2007 to December 2023. We performed quality assessment and data extraction of the included studies, and utilized meta-analysis to evaluate the effects of short-term and long-term ozone exposure on different ASCVD outcomes, including mortality and incidence of ischemic heart disease (IHD) and ischemic stroke (IS). Results A total of 24 studies were included based on a set of predetermined eligibility criteria. The meta-analysis results indicated that short-term ozone exposure was associated with an increased risk of ASCVD mortality and incidence. Specifically, short-term ozone exposure was significantly associated with an elevated risk of IHD mortality (combined RR=1.011, 95%CI: 1.008, 1.015; P < 0.05). Additionally, short-term ozone exposure was significantly linked to increased IS mortality (combined RR=1.005, 95%CI: 1.003, 1.008; P < 0.05) and incidence (combined RR=1.015, 95%CI: 1.003, 1.027; P < 0.05). Conclusion Short-term exposure to ambient ozone significantly elevates acute cardiovascular disease risk. However, the epidemiological association between long-term ozone exposure and ASCVD remains inconclusive. Future high-quality cohort studies with refined exposure assessment methods are warranted to elucidate the chronic cardiovascular effects of ozone exposure.

Volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) are common organic compounds in indoor and outdoor air, and enter the human body primarily through the respiratory tract and directly damage the respiratory system. Previous studies have suggested that exposure to VOCs/SVOCs may associate with the prevalence, incidence, and progression of asthma, but the extent of the associations is still vague. Furthermore, biomarkers for efficient and simple asthma diagnosis, typing, and attack prediction remain unclear at this stage. From the perspective of the collection and detection methods of VOCs/SVOCs, this paper summarized the epidemiological associations and underlying biological mechanisms between VOCs/SVOCs exposure and the prevalence, incidence, and progression of asthma in children/adults. It also demonstrated the application of VOCs/SVOCs in recent years in assisting asthma diagnosis, such as distinguishing asthma patients from the healthy population, differentiating different asthma phenotypes, and predicting asthma acute exacerbations, aiming to provide a scientific basis for improving current asthma management.

Objective To explore the impact of pH value of the reaction system on the properties of bovine hemoglobin modified with aldehydeated polyethylene glycol(PEG-bHb).Methods PEG-bHb conjugates were synthesized under varying pH conditions(6.0,6.5,7.4 and 8.0)of the reaction system while consistent molar ratios,temperature,and reaction time were maintained.The structural and functional attributes of PEG-bHb were characterized.Results The proportion of methemoglobin decreased with an increase in pH.In a weakly acidic reaction environment,the PEG-bHb was found to be relatively highly modified.At pH 6.5,the average number of PEG chains attached to the bHb surface was 6.86±0.38.Selective PEG modification of the N-terminal α-NH2 groups was more pronounced under weakly acidic conditions.Specifically,at pH 6.5,the modification efficiency of the N-terminal α-NH2 groups of bHb by aldehyde-activated PEG reached 95.4％for the α-chains and 99.3％for the β-chains.The PEG modification influenced the heme region microenvi-ronment of bHb,with minimal structural impact observed at pH 6.5.After modification,the oxygen affinity of PEG-bHb was enhanced,the Hill coefficient was reduced,and there were significant increases in colloid osmotic pressure,viscosity,and particle size,all of which differed markedly from the unmodified bHb group(P＜0.001).Conclusion The synthesis of PEG-bHb under weakly acidic conditions can result in a high degree of selective modification of the N-terminal α-NH2 groups and an overall high degree of modification.

Objective To study the effects and mechanism of norcantharidin(NCTD)on proliferation and apoptosis of NB4 and K562 human leukemic cells by regulating phosphoprotein phosphatase 5 catalytic(PPP5C).Methods PC3.1 and PPP5C-PC3.1 plasmids were electroporated into NB4 and K562 cells.Stable NB4 and K562 cell lines were selected with geneticin(G418).Protein and mRNA expression levels of PPP5C were measured by Western blot and RT-qPCR,respectively.Proliferation,migration,and apoptosis of NB4 and K562 cells were determined by a CCK-8 assay,transwell assay,and Live & Dead? animal cell viability/toxicity detection kit,respectively.NB4 and K562 cells were divided into 0 μg/mL NCTD group and various NCTD dose groups,and cultured in RPMI 1640 medium containing 0,8,16,or 32 μg/ml NCTD.The Live & Dead? animal cell viability/toxicity detection kit measured the numbers of dead and live cells,and cell morphology was observed under a microscope.Western blot was used to measure protein expression levels of caspase 3,Cleaved caspase 3,JNK,p-JNK,p38,p-p38,and α-Tubulin.Results Proliferation,migration,and apoptosis of NB4 and K562 cells were enhanced by overexpression of PPP5C.Compared with 0 μg/mL NCTD group,NCTD promoted apoptosis in a dose-dependent manner.PPP5C overexpression antagonized the killing effect of NCTD on leukemic cells.Mechanistic investigations showed that PPP5C reduced the protein level of p-JNK by dephosphorylating and regulating the expression of apoptosis-related protein Cleaved caspase 3.Conclusions NCTD promotes apoptosis of NB4 and K562 cells and inhibits their proliferation by inhibiting PPP5C.

Objective:To investigate personal exposures to nitrogen oxides(NOX)and nitrogen di-oxide(NO2)and the influence of baseline personal characteristics,living environment and daily activity patterns of the participants on the exposures among adults over 35 in Tianjin and Shanghai.Methods:In this panel study,91 healthy nonsmoking adults aged over 35 from Tianjin and Shanghai participated in our study.The study was conducted in summer and winter.The participants were followed for three times with an interval of at least two weeks.Only participants in Shanghai were followed once in winter because of the COVID-19 pandemic.Twenty-seven participants completed follow-up visits in both seasons.We measured their 24 h personal exposures to NOX and NO2and collected their baseline and time-activity in-formation through questionnaire/diary.The linear mixed model was used to analyze the associations be-tween potential influencing factors and personal NOX and NO2 exposure levels.Results:There were 349 follow-up visits with valid 24 h personal NO2 and NOX exposure measurements in the two cities.The ave-rage 24 h personal exposures to NO2 and NOX(volume fraction)in Tianjin participants were 18.0 x 10-9 and 26.2 × 10-9 in summer,and 31.0 x 10-9 and 54.9 x 10-9in winter,respectively;and the average 24 h personal exposures to NO2 and NOX in Shanghai participants were 38.7 x 10-9and 100.0x10-9in summer,and 45.5 x10-9 and 139.2 x 10-9 in winter,respectively.The results of univariate regression analysis showed that their personal NOX exposure levels were significantly associated with city,season,gender,average daily cooking times,and ambient NO2 concentrations measured at fixed-site monitoring stations.In addition to the above factors,the personal NOX exposure levels were also significantly associ-ated with educational level and the personal NO2 exposure levels were also significantly associated with passive smoking,average daily home time,cooking energy type,residential distance from main traffic road,and use of kitchen ventilators.Multivariate regression analysis showed that the personal exposure levels of NO2 and NOX were significantly lower in Tianjin than that in Shanghai,were significantly lower in summer than that in winter,and were significantly and positively associated with ambient NO2 concen-trations measured at fixed-site monitoring stations.In addition,personal NOX exposure levels were signifi-cantly lower in females than in males,and personal NO2 exposure levels were significantly positively asso-ciated with average daily cooking times and significantly inversely associated with average daily home time.For every interquartile range(IQR)increase(12.7 × 10-9)in ambient NO2,the personal NO2 exposure levels increased by 27.5％(95％CI:17.0％-38.9％),and personal NOX exposure levels in-creased by 16.1％(95％CI:7.1％-25.8％).Conclusion:Season,city and ambient NO2 concentra-tions are significant influencing factors of personal exposure levels of NO2and NOX At the same time,the personal exposures levels of NO2 are also affected by lifestyle factors.Our study provides scientific evi-dence for making precise air pollution control decisions and reducing the exposure levels of NOX in the population.

Objective:To assess the impact of exposure to particulate matter with aerodynamic diameter ≤2.5 μm(PM2.5)on non-accidental mortality under different apparent temperature levels and to further explore the modification effect of apparent temperature.Methods:This study used time-series design.Tianjin and Ningbo from China,Bangkok and Chiang Mai from Thailand were selected as the re-search sites,and the apparent temperature was applied as the exposure index.Through the quantitative estimation of the threshold temperature,the corresponding pollutant concentration was divided into high and low levels,and the generalized Poisson additive model was used to evaluate the association between PM2.5 exposure and non-accidental death of residents at different temperature levels.Results:The ave-rage concentrations of PM2.5 in Tianjin,Ningbo,Bangkok,and Chiang Mai during the study period were(73.6±35.6),(48.0±32.1),(33.5±28.4)and(32.6±28.6)μg/m3,respectively;the average daily non-accidental death counts were 148,57,28,and 8.The analysis of the generalized Poisson addi-tive model showed that the daily non-accidental death counts increased by 0.43％(95％CI:0.33％-0.54％)per 10 μg/m3 increase of PM2.5 in lag 0 day in Tianjin of China;0.27％(95％CI:0.08％-0.46％)per 10 μg/m3 increase of PM2.5 in lag 2 days in Ningbo of China.The effect was magnified in high temperature levels in Tianjin and in low temperatures in Ningbo and Bangkok.The mortality effect of PM2 5 in various temperature levels stayed still in co-pollutant regression models.Conclusion:Exposure to fine particulate matter had an adverse effect on non-accidental mortality,which reminded us to give further attention to the pollution control.The findings also indicated that apparent temperature might modify mortality effects of PM2 .5 and the modification effect varied in different regions.Protective policies due to regional differences should be made and more scientific and social attention on mutual effect of air pollution and climate change needs to be appealed.

Objective:To explore the clinical characteristics of hypertriglyceridemic pancreatitis and the correlation between triglyceride (TG) levels and the severity of severe acute pancreatitis (SAP).Methods:A retrospective analysis was conducted on the clinical data of 132 SAP patients admitted to Beijing Friendship Hospital of Capital Medical University from January 2020 to December 2021. They were divided into biliary acute pancreatitis (BAP) group, hypertriglyceridemic pancreatitis (HTGP) group, and alcohol-induced acute pancreatitis (AAP) group based on their etiology. The clinical data and laboratory test results of each group were compared, and the correlation between TG levels and the severity of SAP disease was analyzed.Results:The proportion of male patients, body mass index, length of hospital stay, ICU occupancy rate, C-reactive protein (CRP), TG, and total cholesterol (TC) levels in the HTGP group were significantly higher than those in the BAP and AAP groups. The age of onset, serum calcium (Ca), oxygenation index (PaO 2/FiO 2, P/F), and prothrombin time activity (PTA) in the HTGP group were significantly lower than those in the BAP and AAP groups, and the differences were statistically significant (all P<0.05). There was a negative correlation between TG levels and Ca, P/F, PTA in SAP patients ( r=-0.410, -0.341, -0.365, all P<0.01). Receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) of TG for early prediction of multiple organ dysfunction in SAP patients was 0.868, with a sensitivity of 87% and a specificity of 78%. Conclusions:Patients in the HTGP group have a lower onset age, with more males, obese patients, and critically ill patients. Laboratory indicators such as CRP, TG, and TC levels are higher, while levels of Ca, P/F, and PTA are lower; The serum TG level is correlated with the severity of SAP disease and can be used as one of the early indicators for predicting multiple organ dysfunction in SAP.

Objective:To explore the mechanism of Ma-Xing Shi-Gan decoction combined with Xiao-Chai-Hu decoction (hereinafter referred to as " Sanyang combined treatment" ) in alleviating colon injury in mice infected with influenza virus by transcriptome sequencing technique.Methods:The mouse model of colonic injury caused by influenza virus was induced by intranasal drip of influenza A virus H1N1 suspension. The mice were divided into Control group, Model group, and Sanyang combined treatment (SCT) group. Model group and SCT group were fed with PBS and Ma-Xing Shi-Gan decoction combined with Xiao-Chai-Hu decoction respectively. Seven days later, the colon tissues of each group were taken, the colon length and pathological damage were observed, and the transcriptome was sequenced to screen the significantly different genes between the SCT group and model group for Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis(GSEA).Results:After the therapy with SCT, the length of the colon of mice was significantly improved and the pathological injury of the colon was reduced. There are 92 differentially expressed genes between the SCT group and the model group. GO analysis indicated that the differential genes were enriched in biological processes such as regulation of cytokine and chemokine production, inflammatory response, defense response, immune response, regulation of NF-κB inducing kinase(NIK)/Nuclear factor-κB(NF-κB) signal and Mitogen-activated protein kinase(MAPK) cascade, as well as cell components related to intestinal barrier such as brush border membrane, brush border and microvilli. KEGG analysis indicated that the differential genes were enriched in Toll-like receptor signaling pathway, intestinal immune network for IgA production, complement and coagulation cascade, and Peroxisome proliferator-activated receptor(PPAR) signaling pathway. GSEA indicated that the intestinal immune network for IgA production, PPAR signaling pathway, propionic acid metabolism and butyrate metabolism were significantly up-regulated after the intervention with SCT, while apoptosis and MAPK signaling pathway were significantly down-regulated.Conclusions:Sanyang combined therapy can protect the intestinal tract of mice infected with influenza virus mainly through immunity, inflammation and metabolism pathways.

Objective:To evaluate the safety of double and a half layered esophagojejunal anastomosis in radical gastrectomy.Methods:This prospective, multi-center, single-arm study was initiated by the Affiliated Cancer Hospital of Zhengzhou University in June 2021 (CRAFT Study, NCT05282563). Participating institutions included Nanyang Central Hospital, Zhumadian Central Hospital, Luoyang Central Hospital, First Affiliated Hospital of Henan Polytechnic University, First Affiliated Hospital of Henan University, Luohe Central Hospital, the People's Hospital of Hebi, First People's Hospital of Shangqiu, Anyang Tumor Hospital, First People's Hospital of Pingdingshan, and Zhengzhou Central Hospital Affiliated to Zhengzhou University. Inclusion criteria were as follows: (1) gastric adenocarcinoma confirmed by preoperative gastroscopy;(2) preoperative imaging assessment indicated that R0 resection was feasible; (3) preoperative assessment showed no contraindications to surgery;(4) esophagojejunostomy planned during the procedure; (5) patients volunteered to participate in this study and gave their written informed consent; (6) ECOG score 0–1; and (7) ASA score I–III. Exclusion criteria were as follows: (1) history of upper abdominal surgery (except laparoscopic cholecystectomy);(2) history of gastric surgery (except endoscopic submucosal dissection and endoscopic mucosal resection); (3) pregnancy or lactation;(4) emergency surgery for gastric cancer-related complications (perforation, hemorrhage, obstruction); (5) other malignant tumors within 5 years or coexisting malignant tumors;(6) arterial embolism within 6 months, such as angina pectoris, myocardial infarction, and cerebrovascular accident; and (7) comorbidities or mental health abnormalities that could affect patients' participation in the study. Patients were eliminated from the study if: (1) radical gastrectomy could not be completed; (2) end-to-side esophagojejunal anastomosis was not performed during the procedure; or (3) esophagojejunal anastomosis reinforcement was not possible. Double and a half layered esophagojejunal anastomosis was performed as follows: (1) Open surgery: the full thickness of the anastomosis is continuously sutured, followed by embedding the seromuscular layer with barbed or 3-0 absorbable sutures. The anastomosis is sutured with an average of six to eight stitches. (2) Laparoscopic surgery: the anastomosis is strengthened by counterclockwise full-layer sutures. Once the anastomosis has been sutured to the right posterior aspect of the anastomosis, the jejunum stump is pulled to the right and the anastomosis turned over to continue to complete reinforcement of the posterior wall. The suture interval is approximately 5 mm. After completing the full-thickness suture, the anastomosis is embedded in the seromuscular layer. Relevant data of patients who had undergone radical gastrectomy in the above 12 centers from June 2021 were collected and analyzed. The primary outcome was safety (e.g., postoperative complications, and treatment). Other studied variables included details of surgery (e.g., surgery time, intraoperative bleeding), postoperative recovery (postoperative time to passing flatus and oral intake, length of hospital stay), and follow-up conditions (quality of life as assessed by Visick scores).Result:[1] From June 2021 to September 2022,457 patients were enrolled, including 355 men and 102 women of median age 60.8±10.1 years and BMI 23.7±3.2 kg/m2. The tumors were located in the upper stomach in 294 patients, mid stomach in 139; and lower stomach in 24. The surgical procedures comprised 48 proximal gastrectomies and 409 total gastrectomies. Neoadjuvant chemotherapy was administered to 85 patients. Other organs were resected in 85 patients. The maximum tumor diameter was 4.3±2.2 cm, number of excised lymph nodes 28.3±15.2, and number of positive lymph nodes five (range one to four. As to pathological stage,83 patients had Stage I disease, 128 Stage II, 237 Stage III, and nine Stage IV. [2] The studied surgery-related variables were as follows: The operation was successfully completed in all patients, 352 via a transabdominal approach, 25 via a transhiatus approach, and 80 via a transthoracoabdominal approach. The whole procedure was performed laparoscopically in 53 patients (11.6%), 189 (41.4%) underwent laparoscopic-assisted surgery, and 215 (47.0%) underwent open surgery. The median intraoperative blood loss was 200 (range, 10–1 350) mL, and the operating time 215.6±66.7 minutes. The anastomotic reinforcement time was 2 (7.3±3.9) minutes for laparoscopic-assisted surgery, 17.6±1.7 minutes for total laparoscopy, and 6.0±1.2 minutes for open surgery. [3] The studied postoperative variables were as follows: The median time to postoperative passage of flatus was 3.1±1.1 days and the postoperative gastrointestinal angiography time 6 (range, 4–13) days. The median time to postoperative oral intake was 7 (range, 2–14) days, and the postoperative hospitalization time 15.8±6.7 days. [4] The safety-related variables were as follows: In total, there were 184 (40.3%) postoperative complications. These comprised esophagojejunal anastomosis complications in 10 patients (2.2%), four (0.9%) being anastomotic leakage (including two cases of subclinical leakage and two of clinical leakage; all resolved with conservative treatment); and six patients (1.3%) with anastomotic stenosis (two who underwent endoscopic balloon dilation 21 and 46 days after surgery, the others improved after a change in diet). There was no anastomotic bleeding. Non-anastomotic complications occurred in 174 patients (38.1%). All patients attended for follow-up at least once, the median follow-up time being 10 (3–18) months. Visick grades were as follows: Class I, 89.1% (407/457); Class II, 7.9% (36/457); Class III, 2.6% (12/457); and Class IV 0.4% (2/457).Conclusion:Double and a half layered esophagojejunal anastomosis in radical gastrectomy is safe and feasible.

Objective:To evaluate the safety of double and a half layered esophagojejunal anastomosis in radical gastrectomy.Methods:This prospective, multi-center, single-arm study was initiated by the Affiliated Cancer Hospital of Zhengzhou University in June 2021 (CRAFT Study, NCT05282563). Participating institutions included Nanyang Central Hospital, Zhumadian Central Hospital, Luoyang Central Hospital, First Affiliated Hospital of Henan Polytechnic University, First Affiliated Hospital of Henan University, Luohe Central Hospital, the People's Hospital of Hebi, First People's Hospital of Shangqiu, Anyang Tumor Hospital, First People's Hospital of Pingdingshan, and Zhengzhou Central Hospital Affiliated to Zhengzhou University. Inclusion criteria were as follows: (1) gastric adenocarcinoma confirmed by preoperative gastroscopy;(2) preoperative imaging assessment indicated that R0 resection was feasible; (3) preoperative assessment showed no contraindications to surgery;(4) esophagojejunostomy planned during the procedure; (5) patients volunteered to participate in this study and gave their written informed consent; (6) ECOG score 0–1; and (7) ASA score I–III. Exclusion criteria were as follows: (1) history of upper abdominal surgery (except laparoscopic cholecystectomy);(2) history of gastric surgery (except endoscopic submucosal dissection and endoscopic mucosal resection); (3) pregnancy or lactation;(4) emergency surgery for gastric cancer-related complications (perforation, hemorrhage, obstruction); (5) other malignant tumors within 5 years or coexisting malignant tumors;(6) arterial embolism within 6 months, such as angina pectoris, myocardial infarction, and cerebrovascular accident; and (7) comorbidities or mental health abnormalities that could affect patients' participation in the study. Patients were eliminated from the study if: (1) radical gastrectomy could not be completed; (2) end-to-side esophagojejunal anastomosis was not performed during the procedure; or (3) esophagojejunal anastomosis reinforcement was not possible. Double and a half layered esophagojejunal anastomosis was performed as follows: (1) Open surgery: the full thickness of the anastomosis is continuously sutured, followed by embedding the seromuscular layer with barbed or 3-0 absorbable sutures. The anastomosis is sutured with an average of six to eight stitches. (2) Laparoscopic surgery: the anastomosis is strengthened by counterclockwise full-layer sutures. Once the anastomosis has been sutured to the right posterior aspect of the anastomosis, the jejunum stump is pulled to the right and the anastomosis turned over to continue to complete reinforcement of the posterior wall. The suture interval is approximately 5 mm. After completing the full-thickness suture, the anastomosis is embedded in the seromuscular layer. Relevant data of patients who had undergone radical gastrectomy in the above 12 centers from June 2021 were collected and analyzed. The primary outcome was safety (e.g., postoperative complications, and treatment). Other studied variables included details of surgery (e.g., surgery time, intraoperative bleeding), postoperative recovery (postoperative time to passing flatus and oral intake, length of hospital stay), and follow-up conditions (quality of life as assessed by Visick scores).Result:[1] From June 2021 to September 2022,457 patients were enrolled, including 355 men and 102 women of median age 60.8±10.1 years and BMI 23.7±3.2 kg/m2. The tumors were located in the upper stomach in 294 patients, mid stomach in 139; and lower stomach in 24. The surgical procedures comprised 48 proximal gastrectomies and 409 total gastrectomies. Neoadjuvant chemotherapy was administered to 85 patients. Other organs were resected in 85 patients. The maximum tumor diameter was 4.3±2.2 cm, number of excised lymph nodes 28.3±15.2, and number of positive lymph nodes five (range one to four. As to pathological stage,83 patients had Stage I disease, 128 Stage II, 237 Stage III, and nine Stage IV. [2] The studied surgery-related variables were as follows: The operation was successfully completed in all patients, 352 via a transabdominal approach, 25 via a transhiatus approach, and 80 via a transthoracoabdominal approach. The whole procedure was performed laparoscopically in 53 patients (11.6%), 189 (41.4%) underwent laparoscopic-assisted surgery, and 215 (47.0%) underwent open surgery. The median intraoperative blood loss was 200 (range, 10–1 350) mL, and the operating time 215.6±66.7 minutes. The anastomotic reinforcement time was 2 (7.3±3.9) minutes for laparoscopic-assisted surgery, 17.6±1.7 minutes for total laparoscopy, and 6.0±1.2 minutes for open surgery. [3] The studied postoperative variables were as follows: The median time to postoperative passage of flatus was 3.1±1.1 days and the postoperative gastrointestinal angiography time 6 (range, 4–13) days. The median time to postoperative oral intake was 7 (range, 2–14) days, and the postoperative hospitalization time 15.8±6.7 days. [4] The safety-related variables were as follows: In total, there were 184 (40.3%) postoperative complications. These comprised esophagojejunal anastomosis complications in 10 patients (2.2%), four (0.9%) being anastomotic leakage (including two cases of subclinical leakage and two of clinical leakage; all resolved with conservative treatment); and six patients (1.3%) with anastomotic stenosis (two who underwent endoscopic balloon dilation 21 and 46 days after surgery, the others improved after a change in diet). There was no anastomotic bleeding. Non-anastomotic complications occurred in 174 patients (38.1%). All patients attended for follow-up at least once, the median follow-up time being 10 (3–18) months. Visick grades were as follows: Class I, 89.1% (407/457); Class II, 7.9% (36/457); Class III, 2.6% (12/457); and Class IV 0.4% (2/457).Conclusion:Double and a half layered esophagojejunal anastomosis in radical gastrectomy is safe and feasible.