BACKGROUND: SARS-CoV-2 (COVID-19) is transmitted via infectious respiratory particles. Infectious respiratory particles are released when an infected person breathes, coughs, or speaks. Several studies have measured respiratory particle concentrations through focusing on activities such as breathing, coughing, and short speech. However, few studies have investigated the effect of speech duration. METHODS: This study aimed to clarify the effects of speech duration and volume on the respiratory particle concentration. Study participants were requested to speak at three voice volumes across five speech durations, generating 15 speech patterns. Participants spoke inside a clean booth where particle concentrations and voice volumes were measured and analyzed during speech. RESULTS: Our findings suggest that as speech duration increased, the aerosol number concentration also increased. Through focusing on individual differences, we considered there might be super-emitters who emit more aerosol particles than the average human. Two participants were identified as statistical outliers (aerosol number concentration, n = 1; mass concentration, n = 1). CONCLUSIONS Considering speech duration may improve our understanding of respiratory particle concentration dynamics. Two participants were identified as potential super-emitters.
Humans ; Male ; Speech/physiology* ; Adult ; Female ; COVID-19/transmission* ; Respiratory Aerosols and Droplets ; Voice ; SARS-CoV-2 ; Time Factors ; Young Adult ; Aerosols/analysis*

OBJECTIVE: The study investigates the performance parameters of a nebulizer for pressurized intraperitoneal aerosol chemotherapy (PIPAC). METHODS: Laser diffraction spectroscopy was used to measure the median droplet diameter ( D ₅₀) and spray angle during the steady-state aerosol phase. RESULTS: The minimum droplet diameter of aerosol was achieved when using a nozzle of 0.2 mm diameter and 0.07 mm thickness. The nebulizer could not produce steady-state aerosol when the liquid flow rate was less than or equal to 0.3 mL/s. When the liquid flow rate was greater than or equal to 0.5 mL/s, as the working pressure increased, the median particle size gradually decreased and the spray angle gradually increased. When the pressure is greater than or equal to 200 psi（1 psi=6 894.76 Pa）, as the liquid flow rate increased, the spray angle gradually increased. At a flow rate of 0.7 mL/s and working pressure of 300 psi, the median droplet diameter of aerosol D ₅₀ was 16 μm with a spray angle up to 89.2°. CONCLUSION As a novel intraperitoneal drug delivery technology, PIPAC requires further research focusing on reducing droplet size, expanding drug distribution, improving tissue permeability, and increasing drug concentration.
Nebulizers and Vaporizers ; Aerosols ; Particle Size ; Pressure ; Drug Delivery Systems

OBJECTIVE: To evaluate the immediate effect of Kuanxiong Aerosol (KXA) on perioperative coronary microcirculation in patients with unstable angina (UA) suffering from elective percutaneous coronary intervention (PCI). METHODS: From February 2021 to July 2023, UA inpatients who underwent PCI alone in the left anterior descending (LAD) branch were included. Random numbers were generated to divide patients into the trial group and the control group at a ratio of 1:1. The index of coronary microcirculation resistance (IMR) was measured before PCI, and the trial group was given two sprays of KXA, while the control group was not given. IMR was measured again after PCI, cardiac troponin I (cTnI) and creatine kinase isoenzyme-MB (CK-MB) were detected before and 24 h after surgery, and major cardiovascular adverse events (MACEs) were recorded for 30 days. The data statistics and analysis personnel were blinded. RESULTS: Totally 859 patients were screened, and 62 of them were involved into this study. Finally, 1 patient in the trial group failed to complete the post-PCI IMR and was excluded, 30 patients were included for data analysis, while 31 patients in the control group were enrolled in data analysis. There was no significant difference in baseline data (age, gender, risk factors, previous history, biochemical index, and drug therapy, etc.) between the two groups. In addition, differences in IMR, cTnI and CK-MB were not statistically significant between the two groups before surgery. After PCI, the IMR level of the trial group was significantly lower than that of the control group (19.56 ± 14.37 vs. 27.15 ± 15.03, P=0.048). Besides, the incidence of perioperative myocardial injury (PMI) was lower in the trial group, but the difference was not statistically significant (6.67% vs. 16.13%, P=0.425). No MACEs were reported in either group. CONCLUSIONS KXA has the potential of improving coronary microvascular dysfunction. This study provides reference for the application of KXA in UA patients undergoing elective PCI. (Registration No. ChiCTR2300069831).
Humans ; Percutaneous Coronary Intervention ; Male ; Microcirculation/drug effects* ; Female ; Angina, Unstable/physiopathology* ; Pilot Projects ; Middle Aged ; Aged ; Drugs, Chinese Herbal/pharmacology* ; Aerosols ; Troponin I/blood* ; Coronary Circulation/drug effects* ; Elective Surgical Procedures

Objective: To explore the occupational protective effect of different protective devices on the operators during manual cleaning and oiling of dental handpieces, and to provide a basis for the selection of appropriate protective methods. Methods: From November 2020 to December 2021, 20 high-speed dental handpieces of the same brand were selected and randomly divided into disposable protective bag group and small aerosol safety cabinet group by drawing lots, with 10 in each group. After recording the model, they were distributed to the clinical fixed consulting room for use, and were collected by specially-assigned personnel every day for manual cleaning under the protection of the two devices. By measuring the number of airborne colonies, the concentrations of particulate matter and the satisfaction of operators, the occupational protection effect of the two protective devices on operators was evaluated. Results: Under the protection of the two devices, the average number of airborne colonies after operation was less than 1 CFU/ml. When no protective device was used, the number concentration of particulate matter produced during operation was (21595.70±8164.26) pieces/cm(3). The number concentrations of particles produced by disposable protective bag group [ (6800.24±515.05) pieces/cm(3)] and small aerosol safety cabinet group [ (5797.15±790.50) pieces/cm(3)] were significantly lower than those without any protective device (P<0.001). The number concentration of particle matter of small aerosol safety cabinet group was significantly lower than that of disposable protective bag group (P<0.001). In the satisfaction evaluation of operators, small aerosol safety cabinet group [ (3.53±0.82) points] was significantly better than disposable protective bag group [ (2.23±1.10) points] (P<0.001) . Conclusion: The use of small aerosol safety cabinet during manual cleaning and oiling of dental handpieces has good protective effect, superior safety performance and strong clinical applicability, and has advantages in occupational protection of clinical operators.
Aerosols ; Particulate Matter ; Protective Devices

The wound mechanism, injury characteristics and treatment principles of anti-armored vehicle ammunition against armored crew in the past 20 years are summarized in this paper. Shock vibration, metal jet, depleted uranium aerosol and post armor breaking effect are the main factors for wounding armored crew. Their prominent characteristics are severe injury, high incidence of bone fracture, high rate of depleted uranium injury, and high incidence of multiple/combined injuries. During the treatment, attention must be paid on that the space of armored vehicle is limited, and the casualties should be moved outside of the cabin for comprehensive treatment. Especially, the management of depleted uranium injury and burn/inhalation injury are more important than other injuries for the armored wounds.
Humans ; Uranium/analysis* ; Respiratory Aerosols and Droplets ; Motor Vehicles ; Burns/therapy* ; Multiple Trauma

OBJECTIVE: To explore the effect of Kuanxiong Aerosol (KXA) on isoproterenol (ISO)-induced myocardial injury in rat models. METHODS: Totally 24 rats were radomly divided into control, ISO, KXA low-dose and high-dose groups according to the randomized block design method, and were administered by intragastric administration for 10 consecutive days, and on the 9th and 10th days, rats were injected with ISO for 2 consecutive days to construct an acute myocardial ischemia model to evaluate the improvement of myocardial ischemia by KXA. In addition, the diastolic effect of KXA on rat thoracic aorta and its regulation of ion channels were tested by in vitro vascular tension test. The influence of KXA on the expression of calcium-CaM-dependent protein kinase II (CaMK II)/extracellular regulated protein kinases (ERK) signaling pathway has also been tested. RESULTS: KXA significantly reduced the ISO-induced increase in ST-segment, interventricular septal thickness, cardiac mass index and cardiac tissue pathological changes in rats. Moreover, the relaxation of isolated thoracic arterial rings that had been precontracted using norepinephrine (NE) or potassium chloride (KCl) was increased after KXA treatment in an endothelium-independent manner, and was attenuated by preincubation with verapamil, but not with tetraethylammonium chloride, 4-aminopyridine, glibenclamide, or barium chloride. KXA pretreatment attenuated vasoconstriction induced by CaCl₂ in Ca²⁺-free solutions containing K⁺ or NE. In addition, KXA pretreatment inhibited accumulation of Ca²⁺ in A7r5 cells mediated by KCl and NE and significantly decreased p-CaMK II and p-ERK levels. CONCLUSION KXA may inhibit influx and release of calcium and activate the CaMK II/ERK signaling pathway to produce vasodilatory effects, thereby improving myocardial injury.
Aerosols ; Animals ; Aorta, Thoracic ; Calcium/metabolism* ; Endothelium, Vascular/metabolism* ; Myocardial Ischemia/metabolism* ; Rats ; Vasodilation

Objective: To investigate the epidemiological characteristics and the transmission chain of a family clustering of COVID-19 cases caused by severe acute respiratory 2019-nCoV Delta variant in Changping district of Beijing. Methods: Epidemiological investigation was conducted and big data were used to reveal the exposure history of the cases. Close contacts were screened according to the investigation results, and human and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: On November 1, 2021, a total of 5 COVID-19 cases caused by 2019-nCoV Delta variant were reported in a family detected through active screening. The infection source was a person in the same designated isolation hotel where the first case of the family cluster was isolated from 22 to 27, October. The first case was possibly infected through aerosol particles in the ventilation duct system of the isolation hotel. After the isolation discharge on October 27, and the first case caused secondary infections of four family members while living together from October 27 to November 1, 2021. Conclusion: 2019-nCoV Delta variant is prone to cause family cluster, and close attention needs to be paid to virus transmission through ventilation duct system in isolation hotels.
Aerosols ; COVID-19 ; Epidemics ; Humans ; SARS-CoV-2

Objective: To systematically evaluate the efficacy and safety of rock salt aerosol in the treatment of respiratory tract diseases. Methods: In June 2021, the clinical randomized controlled trial literatures of rock salt aerosol therapy for respiratory tract diseases were searched from CNKI, Wanfang, VIP, Cochrane Library, PubMed database and EMBASE database. Cochrane risk bias evaluation tool was used to evaluate risk bias, Revman 5.4 and Stata16 were used to conduct meta-analysis, TSA 0.9 was used to conduct sequential analysis of trials, and gradepro was used to evaluate evidence quality. Results: A total of 21 literatures were included. According to whether the subjects received rock salt aerosol therapy, they were divided into the experimental group (1125 people) and the control group (973 people) . Compared with the control group, the total clinical effective rate (RR=1.22, 95%CI: 1.15~1.29, P<0.001) , forced expiratory volume in one second (FEV(1)) (WMD=0.20, 95%CI: 0.09~0.31, P<0.001) , percentage of FEV(1) in the predicted value (FEV(1)%) (WMD=5.06, 95%CI: 3.47~6.65, P<0.001) , forced vital capacity (FVC) (WMD=0.22, 95% CI: 0.16~0.27, P<0.001) , maximum expiratory flow (PEF) (WMD=21.312, 95%CI: 9.189~33.435, P=0.004) of experimental group were higher. TSA test shows that the difference conclusions of total effective rate, FEV(1), FEV(1)%, FVC and PEF were reliable, but the conclusion of FEV(1)% needs to be treated with caution; Three literatures reported the adverse reactions in the experimental group; GRADE evidence quality evaluation showed 3 very low-quality evidences and 2 low-quality evidences. Conclusion: Rock salt aerosol therapy combined with conventional therapy has a certain effect on the treatment of respiratory tract diseases, which needs to be further confirmed by high-quality evidence.
Humans ; Respiratory Aerosols and Droplets ; Forced Expiratory Volume ; Vital Capacity ; Respiratory Tract Diseases

The ongoing pandemic of COVID-19 has presented multiple challenges to global healthcare services, dictating changes in almost every aspect of daily medical practice. Performing aerosol generating procedures (AGPs) in the field of interventional pulmonology can lead to profound formation of aerosols, leading to a high risk of infection among healthcare workers (HCWs). We share our experiences on performing AGPs in the midst of a COVID-19 pandemic by focusing on changes in AGP practices. In a pandemic, HCWs ought to adapt to the ever-changing situation and use available resources to provide the best possible healthcare to patients, ensure safety of staff, and continue medical education of future pulmonologists.
Aerosols ; Bronchoscopy/trends* ; COVID-19/transmission* ; COVID-19 Testing ; Humans ; Infection Control/trends* ; Infectious Disease Transmission, Patient-to-Professional/prevention & control* ; Malaysia ; Practice Patterns, Physicians'/trends* ; Tertiary Care Centers ; Thoracoscopy/trends*

Evaporative light scattering detector(ELSD) and charged aerosol detector(CAD) methods were established in this study for the content determination of four kinds of sugars in Zhusheyong Yiqi Fumai(YQFM), and the factors affecting the accuracy of CAD methods were discussed. HPLC-ELSD chromatographic separation was performed on a Shodex Asahipak NH2 P-50 column with acetonitrile-water(75∶25)as the mobile phase, with a flow rate of 0.8 mL·min~(-1), drift tube temperature of 80 ℃. The analysis by HPLC-CAD was performed on the same column with acetonitrile-water as mobile phase for gradient elution, with a flow rate of 0.8 mL·min~(-1), a neb temperature of 45 ℃, and power function(PF) of 1.3. The samples of YQFM were detected by ELSD and CAD respectively. It was found that YQFM was composed of fructose, glucose, sucrose and maltose. The linear relationship of the two methods was good, and the recoveries, reproducibility and stability of these four kinds of sugars measured by the two methods satisfied the requirements of methodology. Both CAD and ELSD detectors were accurate and reliable in detecting saccharides components in YQFM. In addition, it was revealed in this study for the first time that the PF parameter of CAD had an important influence on the accuracy of sugar determination and acted as the key parameter of CAD method. It was also found that for CAD, a non-linear detector, there was no significant difference between the results of linear regression and logarithmic regression.
Aerosols ; Carbohydrates ; Chromatography, High Pressure Liquid ; Light ; Reproducibility of Results ; Scattering, Radiation ; Sugars