OBJECTIVETo investigate the kinetic rate constants ozone and hydroxyl radicals towards two groups of antimicrobials -sulfadiazine (SD) and sulfamethoxazole (SMX).

METHODSThe solute consumption method was used to detect the rate constants of ozone alone with sulfadiazine and sulfamethoxazole, and tertiary butanol was selected as a scavenging agent and pH was adjusted to 2.5 by adding orthophosphate buffers (OB); and the competition kinetics studying methodwith nitrobenzene as a reference was applied to measure the rate constants of hydroxyl radicals towards sulfadiazine and sulfamethoxazole, and pH was adjusted to 7.0 by adding OB.

RESULTSThe rate constants of SD and SMX with ozone alone were 261 mol(-1) · dm(3) · s(-1) and 303 mol(-1) · dm3 · s(-1) by calculating in low reaction system. The rate constants of hydroxyl radicals with SD and SMX were 2.2×1010 mol(-1) · dm(3) · s(-1) and 2.7×1010 mol(-1) · dm(3) · s(-1), respectively. Moreover, the rate constants of hydroxyl radicals with SMX were found to have increased from 3.6×109 mol(-1) · dm(3) · s(-1) to 2.8×1010 mol(-1) · dm(3) · s(-1) with pH value rising from 5.0 to 7.8.

CONCLUSIONSMX and SD are both refractory to ozone oxidation alone, and are liable to be degraded by hydroxyl radicals, and the rate constants of SMX with the hydroxyl radical slightly increases with pH rise.

Hydroxyl Radical ; chemistry ; Kinetics ; Ozone ; chemistry ; Sulfamethoxazole ; chemistry ; Sulfonamides ; chemistry ; Water ; chemistry

【Objective】 To explore the status quo and influencing factors of knowledge, attitude and practice of voluntary blood donation among undergraduates in Beijing. 【Methods】 A questionnaire was designed on the basis of literature, using the method of convenience sampling to survey the undergraduates from 39 universities in Beijing. The t-test, analysis of variance and χ² test were used to compare the differences in knowledge, attitude and practice of voluntary blood donation among different groups, and logistic regression model was performed to analyze the influencing factors. 【Results】 A total of 1 075 valid questionnaires were collected from undergraduates of 39 universities in Beijing. The results showed that the proportion of the participants who had good knowledge about voluntary blood donation was 69.21% (744/1 075). No statistically significant difference was noticed on the scores of voluntary blood donation knowledge between males and females (P>0.05). The scores of voluntary blood donation knowledge of medical students were higher than those of other subjects (P<0.05). The scores of voluntary blood donation knowledge of juniors and above were higher than those of lower grades (P<0.05). The rate of undergraduates participating voluntary blood donation in Beijing was 30.98% (333/1 075). A total of 67.26% (723/1 075) of students had donation intention, 9.49% (102/1 075) didn’t and 23.25% (250/1 075) were not sure. No statistically significant differences in blood donation intention were observed among undergraduates by genders and grades (P>0.05). The rate of medical students’ intention to donate blood was higher than that of other subjects (P<0.05). 【Conclusion】 The rate of voluntary blood donation among undergraduates in Beijing was above the middle level compared with other regions in China, but the practice of voluntary blood donation is far away from the intention. Therefore, it’s necessary to improve the level of knowledge, attitude and practice of undergraduates, especially non-medical college students, so as to improve the rate of voluntary blood donation among the undergraduates in Beijing.

OBJECTIVE To explore the effects of levosimendan on cardiac function， hemodynamics and prognosis of patients with septic shock complicated with myocardial depression， and evaluate the safety of levosimendan. METHODS Patients with septic shock complicated with myocardial depression who were admitted to the Department of Critical Care Medicine of Chongqing University Three Gorges Hospital from April 2021 to August 2023， underwent adequate fluid resuscitation， had a mean arterial pressure （MAP） ≥65 mmHg， and received pulse indicator continuous cardiac output （PiCCO） monitoring were enrolled. The patients were randomly divided into dobutamine group and levosimendan group according to a random number table， with 20 patients in each group. Both groups received intravenous infusion of Norepinephrine bitartrate injection at a dose of 0.1-2.0 μg/（kg·min）. On this basis， the dobutamine group additionally received intravenous infusion of Dobutamine hydrochloride injection at a dose of 5- 10 μg/（kg·min） for 3 to 7 days， while the levosimendan group additionally received intravenous infusion of Levosimendan injection at a dose of 0.1-0.2 μg/（kg·min） for 24 hours. Heart rate （HR） and hemodynamic parameters [systolic blood pressure， diastolic blood pressure， MAP， central venous pressure （CVP）]， PiCCO monitoring parameters [cardiac function index （CFI）， cardiac index （CI）， stroke volume index （SVI）， extravascular lung water index， global end-diastolic volume index， pulmonary vascular permeability index （PVPI）， global ejection fraction （GEF）， systemic vascular resistance index， left ventricular contractility index]， and prognosis indicators [death within 3 days after administration， mechanical ventilation time，intensive care unit （ICU） stay time， 28-day mortality rate] were compared between the two groups before treatment and at 24 and 72 hours after treatment. Adverse reactions were E-mail：recorded for both groups. RESULTS Compared with before treatment in the same group， CFI， CI and GEF at 24 hours after treatment， CI and GEF at 72 hours after treatment in the dobutamine group， as well as SVI at 24 hours after treatment and SVI and GEF at 72 hours after treatment in the levosimendan group were significantly increased； PVPI at 72 hours after treatment in the dobutamine group was significantly decreased （P＜0.05）. Compared with the dobutamine group during the same period， patients in the levosimendan group had significantly lower HR and significantly higher CVP at 24 hours after treatment （P＜0.05）. Within 3 days after administration， there were no deaths in either group； there were no statistically significant differences in mechanical ventilation time， ICU stay time， 28-day mortality rate， or the incidence of adverse reactions between the two groups （P＞0.05）. CONCLUSIONS For patients with septic shock complicated with myocardial depression who have undergone adequate fluid resuscitation and have a MAP of ≥65 mmHg， levosimendan is comparable to dobutamine in improving cardiac function and hemodynamic parameters， without affecting patients’ prognosis or increasing the risk of adverse reactions such as hypotension.