Comparison of the inward leakage rate between N95 filtering facepiece respirators and modified surgical masks during the COVID-19 pandemic

BACKGROUND@#Owing to shortage of surgical and N95 filtering facepiece respirators (FFRs) during the COVID-2019 pandemic, various masks were developed to prevent infection. This study aimed to examine the inward leakage rate (ILR) of sealed face masks and modified surgical masks using a quantitative fit test and compared it with the ILR of unmodified N95 FFRs.@*METHODS@#We conducted paired comparisons of ILRs of bent nose-fit wire masks, double masks, and N95 FFRs from October to December 2021. To measure the protective effectiveness of masks, participants wore masks, and the number of particles outside and inside the mask were measured. The ILR was based on the percentage of particles entering the mask using a fit tester.@*RESULTS@#We enrolled 54 participants (20 men and 34 women) in this study. The median ILR for surgical masks without and with a W-shaped bend in the nose-fit wire were 96.44% and 50.82%, respectively. The nose-fit wire adjustment reduced the ILR of surgical masks by a mean of 28.57%, which was significantly lower than the ILR without adjustment (P < 0.001). For double masks, with surgical or polyurethane masks on top of the W-shaped mask, the ILR did not differ significantly from that of N95. Although the filtration performance of double surgical masks matched that of N95 masks, their ILR was notably higher, indicating that double masks do not provide equivalent protection.@*CONCLUSIONS@#Wearing N95 masks alone is effective in many cases. However, surgical mask modifications do not guarantee consistent effectiveness. Properly selected, sealed masks with a good fit overcome leakage, emphasizing their crucial role. Without evidence, mask-wearing may lead to unexpected infections. Education based on quantitative data is crucial for preventing adverse outcomes.

Structural Design and Penumbra Analysis of Dynamic Multi-leaf Collimator Leaf End / 中国医疗器械杂志

Dynamic multi-leaf collimator, which has the function of radiation beam shaping, is a key executive component of tumor precise radiotherapy, and plays a core role in improving the accuracy, efficiency and quality of radiotherapy. A new type of collimator leaf end structure with circular arc and plane combination was studied, and collimator penumbra performance analysis model combining analytical expression and graphic analysis was developed. The influence of leaf end structure on penumbra was analyzed quantitatively, and a set of three-dimensional structure design of dynamic multi-leaf collimator was completed. The feasibility of the structural design and analysis model was verified through experimental measurements.

Inhibitory Effect of Sophora alopecuroides Total Alkaloids and Two Monomer Alkaloids on PC12 Cell Activity / 中国实验方剂学杂志

ObjectiveTo compare the effects of total alkaloids， matrine， and sophoridine extracted from Sophora alopecuroides on the activity of pheochromocytoma cells （PC12 cells）. MethodThe effect of S. alopecuroides total alkaloids， matrine， and sophoridine at concentrations of 2， 1， 0.5， 0.25， 0.125， and 0.062 5 g·L-1 on the proliferation of PC12 cells was evaluated using the 3-（4，5-dimethylthiazol-2-yl）-2，5-diphenyl tetrazolium bromide （MTT） assay. The lactate dehydrogenase （LDH） leakage rate was measured by enzyme-linked immunosorbent assay （ELISA）. Flow cytometry was used to assess cell apoptosis rate， cell cycle distribution， and intracellular Ca2+ levels. Real-time quantitative polymerase chain reaction （Real-time PCR） was performed to determine the mRNA transcription levels of B-cell lymphoma-2 （Bcl-2） and Bcl-2-associated X protein （Bax）. Protein expression levels of apoptosis-related proteins Caspase-3， Caspase-8， Bcl-2， and Bax were detected by Western blot. ResultCompared to the control group， S. alopecuroides total alkaloids， matrine， and sophoridine inhibited the proliferation of PC12 cells， increased LDH leakage rate， enhanced intracellular Ca2+ fluorescence intensity， and induced cell apoptosis in concentration-dependent manner （P<0.05， P<0.01）. Among them， S. alopecuroides total alkaloids had the strongest inhibitory effect on cell proliferation and induction of apoptosis in PC12 cells （P<0.01）. After treatment with S. alopecuroides total alkaloids， matrine， and sophoridine， the cell cycle progression of PC12 cells was arrested at G1/G0 in the S. alopecuroides total alkaloids group， and at G1/S in the matrine and sophoridine groups. The expression levels of Bax mRNA were significantly increased （P<0.05， P<0.01）， while the expression levels of Bcl-2 mRNA were significantly decreased （P<0.05， P<0.01）. All treatments significantly downregulated the expression of the anti-apoptotic protein Bcl-2 （P<0.05， P<0.01） and upregulated the expression of the pro-apoptotic proteins Bax， Caspase-3， and Caspase-8 （P<0.05， P<0.01）， with the most significant protein expression changes observed in the S. alopecuroides total alkaloids group. ConclusionAmong the S. alopecuroides total alkaloids， matrine， and sophoridine， S. alopecuroides total alkaloids exhibit the strongest inhibitory effect on the activity of PC12 cells， and its mechanism of action may be related to the inhibition of anti-apoptotic protein expression， upregulation of pro-apoptotic protein expression， and activation of the mitochondrial Caspase-8 apoptotic pathway.

Clinical application of extracorporeal pneumatic reduction combined with bone-filled mesh bag implantation for the treatment of thoracolumbar osteoporotic burst fracture without spinal cord injury / 中国骨伤

OBJECTIVE@#To compare the clinical efficacy of pneumatic reduction combined with bone-filled mesh bag implantation and pneumatic reduction combined with kyphoplasty in the treatment of thoracolumbar burst fracture without spinal cord injury.@*METHODS@#The clinical data of 160 patients with thoracolumbar osteoporotic burst fracture without spinal cord injury treated from January 2014 to July 2017 were retrospectively analyzed. There were 66 males and 94 females, aged from 72 to 84 years old with an average of 76.4 years old. The patients were divided into two groups according to different surgical methods, including 80 cases of pneumatic reduction combined with bone-filled mesh bag implantation(treatment group) and 80 cases of pneumatic reduction combined with kyphoplasty(control group). The intraoperative bone cement leakage rate was compared between two groups. The height of the injured vertebrae was measured by X-rays preoperatively and 6-month postoperatively in order to assess height loss of injured vertebrae. VAS score and ODI score were used for follow-up to assess lumbar back pain and autonomic dysfunction before surgery and 2 weeks, 6 months, 1 year after surgery.@*RESULTS@#In treatment group, 3 cases occurred bone cement leakage during operation and leakage rate was 3.75%(3/80); In control group, 14 cases had cement leakage with leakage rate of 17.5%; The difference between two groups was statistically significant(<0.05). All patients were followed up for 13 to 24 months with an average of 14.6 months. Among them, 2 cases occurred postoperative infections which were superficial infections. After oral antibiotics and outpatient treatment infections were controlled. At 6 months after surgery, the height of the injured vertebra was measured by X-ray. Treatment group recovered (5.12±1.31) % and control group recovered (14.11±1.17) %. The difference between two groups was statistically significant (<0.05). At 1 year after surgery, ODI score was 4.03±1.62 in treatment group and 10.03±1.54 in control group. The difference between two groups was statistically significant(<0.05). VAS score was 1.03±0.62 in treatment group and 2.67±0.55 in control group. The difference between groups was statistically significant(<0.05).@*CONCLUSIONS@#Extracorporeal pneumatic reduction combined with bone-filled mesh bag implantation technique can significantly reduce the occurrence of intraoperative cement leakage in the treatment of thoracolumbar osteoporotic burst fractures, effectively improve reposition of the injured vertebrae, relieve the pain and recover the function of lower back. However, high price of bone-filled mesh bags obstructs its clinical popularization.

Effect of quality control cycle on reducing the false negative rate of minimal residual disease of flow cytometry in patients with acute myeloid leukemia / 白血病·淋巴瘤

Objective To analyze the application of quality control cycle (QCC) in reducing the false negative rate of minimal residual disease (MRD) of flow cytometry in patients with acute myeloid leukemia (AML). Methods In AML patients with abnormal fusion gene detected in hematology laboratory of Changhai Hospital during the year of 2014, the prevalence of AML-MRD detected both by flow cytometry (FCM) and real-time fluorescence quantitative polymerase chain reaction (FQ-PCR) were analyzed retrospectively. The possible causes of false negative rate of flow cytometric MRD referring to PCR were further deeply analyzed, and the improvement measures were adapted from January 2015 to December 2015 and further judged all according to the QCC methods. Results Pareto diagram showed that the dilution and coagulation of the specimen, the improper analysis strategy and the incomplete combination of the MRD index [composition ratio:83.3 % (60/72)] were the main factors leading to the leakage of FCM MRD in 2014. The QCC group devised measures to reduce the dilution probability of bone marrow and develop a standard operating procedures (SOP) for sampling and testing, strengthen the maintenance of the flow instrument and more importantly, focused on optimizing the antibody panels and gated strategies referring to the current two main kinds of MRD detection combination modes on the basis of the latest advances published in 2015. Finally, the undetected rate of AML-MRD was reduced by FCM from 14.8 % (72/486) in 2014 to 2.6 % (16/620) in 2015. Conclusions The QCC can effectively reduce the leakage rate of flow cytometric AML MRD, improve the ability of laboratory quality control and the ability to solve problems. Solving problems with QCC is thus worthy of being popularized.

Effects of Health Education Prescription on the Reduction of Intravenous Dripping Leakage in Obstetrics and Gynecology Department of Our Hospital / 中国药房

OBJECTIVE:To investigate the influence of health education prescription on the reduction of intravenous dripping leakage in obstetrics and gynecology department of our hospital. METHODS:Totally 300 inpatients selected from obstetrics and gy-necology department of our hospital Jun.-Nov. 2015 were divided into observation group and control group according to random number table,with 150 cases in each group. Control group received health education of daily operation during intravenous dripping. In observation group,intravenous dripping treatment card came with a health education prescription of intravenous dripping,which facilitate the patients and families to consult;the nurses carried out health education for patients every day during dripping in accor-dance to the prescriptions;clinical pharmacists accompanied resident physicians to make patient round and conducted random health education inspection. Awareness rate of health education prescription content,satisfactory rate of treatment,dripping rate of Magne-sium sulfate injection and Cefazolin sodium for injection,the incidence of ADR were compared between 2 groups. The intravenous dripping leakage were observed in 2 groups. RESULTS:The awareness rate of health education prescription content and satisfactory rate of treatment were 94.0% and 96.0% in observation group,which was significantly higher than 70.35% and 85.75% of control group,with statistical significance (P<0.05). The dripping rate of Magnesium sulfate injection <40 drops/min accounted for 97.6% in observation group,which was significantly higher than 91.6% of control group;the incidence of ADR was 0.3% in ob-servation group,which was significantly lower than 1.3% of control group. The dripping rate of Cefazolin sodium for injection <60 drops/min accounted for 92.3%,which was significantly higher than 85.0% of control group;the incidence of ADR was 0.4%in observation group,which was significantly lower than 1.0% of control group,with statistical significance(P<0.05). The intra-venous dripping leakage rate was 5.5%in observation group,which was significantly lower than 9.5%of control group,with statis-tical significance(P<0.05). CONCLUSIONS:Health education prescription can significantly improve satisfactory degree of treat-ment and reduce ADR and leakage during intravenous dripping

Analysis on leakage factors and their correlation of iodine contrast agent in CT enhanced scanning / 重庆医学

Objective To explore the related factors of contrast agent leakage in CT enhanced scanning and to find out its preventive measures.Methods The clinical data of 46 patients with iodine leakage in the CT enhanced scanning during 2015 were retrospectively analyzed.Results The leakage rate had statistically significant difference between different patient's genders(P＜0.05).The leakage rate was related to the age of the patients(P＜0.01).The leakage rate showed the increasing trend with the increase of injection rate(P＜0.05).The leakage rate was related to the concentration of the contrast agent(P＜0.05).The leakage rate had no increasing trend with the increase of injection dose(P=0.675).The leakage rate was related to the years of injection nurses engaging this working(P＜0.01).Conclusion The leakage rate of female patients was higher than that of male.The older the patients,the greater the contrast agent concentration,the faster the injection rate and the lower the working years of injection nurses,the greater the leakage rate.

Analysis on leakage factors and their correlation of iodine contrast agent in CT enhanced scanning / 重庆医学

Objective To explore the related factors of contrast agent leakage in CT enhanced scanning and to find out its preventive measures.Methods The clinical data of 46 patients with iodine leakage in the CT enhanced scanning during 2015 were retrospectively analyzed.Results The leakage rate had statistically significant difference between different patient's genders(P＜0.05).The leakage rate was related to the age of the patients(P＜0.01).The leakage rate showed the increasing trend with the increase of injection rate(P＜0.05).The leakage rate was related to the concentration of the contrast agent(P＜0.05).The leakage rate had no increasing trend with the increase of injection dose(P=0.675).The leakage rate was related to the years of injection nurses engaging this working(P＜0.01).Conclusion The leakage rate of female patients was higher than that of male.The older the patients,the greater the contrast agent concentration,the faster the injection rate and the lower the working years of injection nurses,the greater the leakage rate.

Effects of tetramethylpyrazine-2′-O-sodium ferulate on swelling of astrocytes and expression of AQP4 after oxygen-glucose deprivation/reoxygenation / 中国药理学通报

Aim To explore the effects of tetrameth-ylpyrazine-2′-O-sodium ferulate (TSF)on the swelling of astrocytes and the expression of AQP4 after oxygen gl-ucose deprivatio /reoxygenation(OGD /Reox).Methods Astrocytes were divided into 4 groups:control group, OGD /Reox group,Ozagrel group and TSF group.The effects of TSF on astrocytes were investigated 6,1 2,24 and 48 h after OGD /Reox.The cell injury was assessed by measuring LDH activity and MTT.The expression levels of AQP4 protein of astrocytes were detected u-sing Western blot.Results OGD /Reox induced obvi-ous cell swelling and significant reduction of LDH in astrocytes whereas TSF remarkably attenuated OGD-in-duced astrocyte swelling and LDH reduction (P group(P 0.05 ).Conclusion TSF can attenuate OGD-induced swelling of astrocytes through decreasing the AQP4 expression.

Determination test of the leakage rate and over-expansion property of the expander / 中华医学美学美容杂志

Objective To measure the leakage rate in the process of expansion in vivo and in normal saline and the over-expansion property of the expander.Methods We chose 17 cases that were treated with the skin expansion.We recorded total injected saline volume intentionally in these cases before the second surgery,and recorded the remainder of the volume of saline postoperatively.We injected normal saline into 8 expanders,respectively,exceeding 50％ of the volume-rating;and subsequently put these expanders into plastic bucket filled with saline.30 days after,we measured the remaining volume of the normal saline.We injected 100 ml normal saline into 4 expanders,respectively,of which nominal volume was 100 ml,and then left these expanders in saline and measured the remainder volume of the saline 30 days later.In the second time,we injected 150 ml and repeated the abovementioned process.It was repeated 7 times until the injection volume reached 400 ml.We processed the data and depicted a curve of effective expansion.Results The results showed that the leakage rate reached (29.0+12.5) ％ in vivo.Experiments in vitro confirmed that 85.0％ (8.0/9.4) of the saline leaked through the injection port and 14.8％ (1.4/9.4) leaked through the membrane of the expander.In addition,over-expansion performance index test confirmed that the over-expansion property of an expander was about twice the nominal volume.Conclusions The expander is not completely sealed structure.Normal saline can leak through the injection part and the membrane of the expander.The over-expansion property of an expander is limited.When the volume injected into the expander exceeds a certain value,the effective expansion performance is not increased with it.