Corrección del artefacto producido en imágenes tomográficas en equipos odontológicos / Correction of the artifact produced in tomographic images in dental equipment

Objetivo: disminuir el efecto de artefacto que generan objetos de alta densidad mediante la utilización de filtros de distintos materiales y espesores, ubicados en lugares estratégicos del tomógrafo. Material y métodos: se utilizaron filtros de aluminio y de cobre ubicados en lugares estratégicos en el equipo tomográfico. Se realizaron cortes oblicuos en piezas dentarias con restauraciones metálicas y en implantes; se midió la extensión del artefacto en ancho y alto en cada adquisición tomográfica. Resultados: se hallaron diferencias significativas respecto a la disminución de la dispersión de acuerdo con cada filtro con respecto a la no utilización de estos elementos. Conclusión: la utilización de filtros logró disminuir el efecto de artefacto en estructuras de alta densidad, obteniendo una mejor calidad de imagen para el diagnóstico, permitiendo que el software pueda reconstruir una imagen real (AU)

Objective: to diminish the artifact effect generated by high density objects by using filters of different materials and thickness, located in strategic places of the tomograph. Material and methods: aluminum and copper filters located in strategic places in the tomographic equipment were used. Oblique cuts were made on dental pieces with metal restorations and implants; the extension of the artifact in width and height was measured in each tomographic acquisition. Results: significant differences were found regarding the decrease of the dispersion according to each filter with respect to the non-use of these elements. Conclusion: the use of filters achieves to diminish the artifact effect in structures of high density, obtaining a better image quality for the diagnosis, allowing the software to reconstruct a real image (AU)

Improvement of bovine pestiviral diagnosis by the development of a cost-effective method for detecting viral RNA in fresh specimens and samples spotted in filter papers / Optimización del diagnóstico de Pestivirus bovinos mediante el desarrollo de una metodología económica para detectar ARN viral en muestras frescas y fijadas en papeles de filtro

Abstract Bovine pestiviruses are the causative agents of bovine viral diarrhea, a disease thatcauses severe economic losses in cattle. The aim of this study was to improve their diagnosisby developing a RT-qPCR to detect bovine pestiviruses A, B and H; and to set up a protocolfor collecting, shipping and preserving bovine pestiviral RNA on filter papers. The developedRT-qPCR showed high sensitivity in detecting these viruses in different matrices: viral stocks,semen and serum samples. With regard to the possibility of using the technique to test serumpools, it was possible to identify a positive serum sample within a pool containing 30 sera.In addition to evaluating the qPCR from fresh samples, the use of filter papers to sow bovinesamples was analyzed. The sampling method on two different filter papers using bovine blooddrops was a useful alternative for diagnostic purposes and allowed to preserve pestiviral RNAfor up to 12 months under refrigeration.

Resumen Los Pestivirus bovinos son los agentes causales de la diarrea viral bovina, una enfermedad que genera importantes pérdidas económicas en el ganado vacuno. El objetivo de este trabajo fue mejorar su diagnóstico mediante el desarrollo de una RT-qPCR para detectar los Pestivirus bovinos A, B y H y disenar un protocolo de recolección, envío y conservación de ARN viral en papeles de filtro. La RT-qPCR desarrollada demostró alta sensibilidad en la detección de estos virus en diferentes matrices: stock viral, suero y semen. Respecto de la posibilidad de usar la técnica para testear pools de suero, fue posible identificar un suero positivo dentro de un pool compuesto por 30 sueros. Además de evaluar la qPCR en muestras frescas, se analizó el uso de papeles de filtro para sembrar muestras de bovinos. La metodología de toma de muestras en dos tipos de papeles de filtro usando gotas de sangre fue una alternativa útil para el diagnóstico y permitió conservar ARN viral por hasta 12 meses a temperaturas de refrigeración.

Biocompatibility of the Oxygenator on Pulsatile Flow by Electron Microscope

ABSTRACT Introduction: Extracorporeal perfusion flow type requires further investigation. The aim of this study is to compare the effects of pulsatile and nonpulsatile flow on oxygenator fibers that were analyzed by scanning electron microscope (SEM) and to extensively study patients' coagulation profiles, inflammatory markers, and functional blood tests. Methods: Twelve patients who had open heart surgery were randomly divided into two groups; the nonpulsatile flow (group NP, six patients) and pulsatile flow (group P, six patients) groups. Both superficial view and axial sections of the oxygenator fiber samples were examined under SEM to compare the thickness of absorbed blood proteins and amount of blood cells on the surface of oxygenators. Platelet count, coagulation profile, and inflammatory predictors were also studied from the blood samples. Results: Fibrinogen levels after cardiopulmonary bypass were significantly lower in group NP (group P, 2.57±2.78 g/L; group NP; 2.39±0.70 g/L, P=0.03). Inflammatory biomarkers such as C-reactive protein, interleukin (IL)-6, IL-12, apelin, S100β, and tumor necrosis factor alpha were comparable in both groups. Axial sections of the oxygenator fiber samples had a mean thickness of 45.2 µm and 46.5 µm in groups P and NP, respectively, and this difference is statistically significant (P=0.006). Superficial view of the fiber samples showed obviously lower platelet, leukocyte, and erythrocyte levels in group P. Conclusion: Our study demonstrated that both cellular elements and protein adsorption on oxygenator fibers are lower in the group P than in the group NP. Pulsatile perfusion has better biocompatibility on extracorporeal circulation when analyzed by SEM technique.

Smartphone co-aided cobalt blue anterior segment with intraocular lens photography

In this report, we have utilized a smartphone-based innovative tool named anterior segment photography with an intraocular lens (ASPI) with a cobalt blue filter on the smartphone flash for photographing fluorescein-stained corneas. An intraocular lens along with a cobalt blue filter was attached to the smartphone camera to achieve this purpose. The filter could block out all wavelengths of light except the blue wavelength (450–490 nm) emerging from the smartphone camera. A pilot study was conducted on 27 eyes of 25 patients where images of various corneal pathologies were obtained using ASPI blue light imaging. The images were clear and highly magnified and could be used for documentation, teleconsultation for expert opinion, education, and monitoring of disease progression. ASPI-aided blue light imaging could be easily fabricated and is a frugal inexpensive device, which is used by different ophthalmic personnel to obtain fluorescein-stained corneal images.

Effect of respiratory filter on pulmonary function in occupational health examination / 中华劳动卫生职业病杂志

Objective: To explore the influence and significance of respiratory filter on the judgment of pulmonary function and the conclusion of occupational health examination in occupational health examination. Methods: From August to November 2020, 252 occupational health examinees were randomly selected as the research objects, and the lung function was examined with the respiratory filter bite and the straight cylinder bite without filter, respectively. The lung function examination indexes and the qualification rate of lung function examination were analyzed and compared between the two groups, and the diagnostic criteria of lung function examination was corrected. Results: 252 subjects were 36 (30, 42) years old. The qualified rate of lung function examination with respiratory filter bite (28.17%, 71/252) was lower than that with straight cylinder bite (34.92%, 88/252) , the difference was statistically significant (P<0.05) . The percentage of forced vital capacity in normal predicted value (FVC%) , percentage of forced expiratory volume in the first second in normal predicted value (FEV(1)%) , and percentage of forced expiratory volume in the first second in forced vital capacity (FEV(1)/FVC%) of subjects using respiratory filter bite were lower than those using the straight cylinder bite (P<0.05) . The corrected diagnostic criteria of pulmonary function were FVC%>78%, FEV(1)%>77%, FEV(1)/FVC%>68%. There was no significant difference between the qualified rate of the respiratory filter bite lung function test calculated according to the corrected diagnostic criteria (35.71%, 90/252) and the qualified rate of the straight cylinder bite lung function test calculated according to the original diagnostic criteria (34.92%, 88/252) (P>0.05) . Conclusion: In occupational health examination, the use of respiratory filter may affect the results of pulmonary function examination. The diagnostic criteria of pulmonary function can be corrected according to different filtering effects to ensure the accuracy of the conclusions of occupational health examination.

Uncalibrated Positioning Method for Puncture Robots Based on Optical Navigation / 中国医疗器械杂志

Robotic puncture system has been widely used in modern minimally invasive surgery, which usually uses hand-eye calibration to calculate the spatial relationship between the robot and the optical tracking system. However, the hand-eye calibration process is time-consuming and sensitive to environmental changes, which makes it difficult to guarantee the puncture accuracy of the robot. This study proposes an uncalibrated positioning method for puncture robot based on optical navigation. The method divides the target path positioning into two stages, angle positioning and position positioning, and designs angle image features and position image features respectively. The corresponding image Jacobian matrix is constructed based on the image features and updated by online estimation with a cubature Kalman filter to drive the robot to perform target path localization. The target path positioning results show that the method is more accurate than the traditional hand-eye calibration method and saves significant preoperative preparation time by eliminating the need for calibration.

Comparison of visual function before and after wearing amber filter in low vision patients with primary retinitis pigmentosa / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To compare the visual function of low-vision patients with primary retinal pigmentosa(RP)before and after wearing amber filter.METHODS: Self-control before and after study. A total of 30 patients(60 eyes)with low vision who were diagnosed with primary RP in the ophthalmology clinic of Xi'an No.1 Hospital from August 2021 to March 2022 were collected. The uncorrected distance visual acuity(UCDVA), best-corrected distance visual acuity(BCDVA), uncorrected near visual acuity(UCNVA), best-corrected near visual acuity(BCNVA), visual field and Farnsworth-Munsell(FM)-100 color visions were recorded before and after wearing amber filter. The contrast sensitivity(CS)in three visual environments including bright room, darkroom and darkroom with glare was measured and recorded respectively, and the changes of those parameters were analyzed before and after wearing filter.RESULTS: UCDVA and BCDVA after wearing the filter were better than those before wearing(t=-2.32, P&#x0026;#x003C;0.001; t=-6.77, P&#x0026;#x003C;0.001), while there was no statistically significant difference in UCNVA and BCNVA before and after wearing filter. The visual field index(VFI)after wearing filter was lower than that before wearing(t=8.62, P&#x0026;#x003C;0.001), and the mean defect(MD)of visual field was greater than that before wearing(t=7.73, P&#x0026;#x003C;0.001). FM100 color chess test showed that both total error score(TES)and partial error score(PES)in multiple regions were higher than those before wearing filter(P&#x0026;#x003C;0.001). After wearing, the CS of each frequency band in the environment of bright room and darkroom with glare was higher than that before wearing(P&#x0026;#x003C;0.001), and there was no statistically significant difference in each frequency band before and after wearing amber filter under the environment of darkroom without glare.CONCLUSION: Patients with low vision of primary RP showed improved UCDVA and BCDVA, but unchanged UCNVA and BCNVA after wearing amber filter, while the visual field and color discrimination were worse than those before wearing filter. The CS of the bright room and darkroom with glare environment was improved than before wearing filter, while there were no significant changes in CS under darkroom without glare.

A Ventricular Fibrillation Recognition Method Based on Random Forest and BP Neural Network / 中国医疗器械杂志

Ventricular fibrillation is the most common pathophysiological mechanism leading to cardiac arrest. If cardiac arrest can be rescued in time, the survival rate of patients can be greatly improved. Therefore, rapid and accurate identification of ventricular fibrillation is extremely important. This paper proposes an automatic detection algorithm for ventricular fibrillation based on random forest and BP (back propagation) neural network. Pass the ECG signal through a 6 s moving window, calculate 6 kinds of characteristic parameters according to the time-frequency domain information of the signal, use these 6 kinds of characteristic parameters as the input of the classifier, carry out classification and test, and give the authoritative experts in the database. A total of 44 cases of related data were used to evaluate the method. The results show that using the ten-fold cross-validation method, the accuracy of classification of ventricular fibrillation in the CU database (Creighton University Ventricular Tachyarrhythmia Database) and the AHA database (the American Heart Association Database) has reached 96.38% and 99.45%, which has certain applicability.

Clinical application of the convertible vena cava filter / 中华普通外科杂志

Objective:To evaluate the short-term efficacy, safety and complications of convertible vena cava filter.Methods:The clinical and follow-up data of 103 patients who were placed with the convertible vena cava filter from May 2017 to May 2018 were retrospectively analyzed.Results:The convertible vena cava filters were successfully implanted in all cases. Twenty-seven cases underwent filter conversion, and 26 cases were successfully converted (5-145 days after implantation). None of them had complications such as thrombus formation, displacement, tilt, fracture or vein wall penetration. The reasons for no conversion included age (18.4%, 19/103), high-risk patients (12.6%, 13/103), limited organ function (9.7%, 10/103), etc. Ninety-four patients (91.3%) were followed up for 6 months. One developed thrombus in the filter, 3 developed lower limb venous thrombosis without inferior vena cava occlusion, and no patients were found with symptomatic pulmonary embolism.Conclusions:The convertible vena cava filter can safely and effectively reduce the incidence of perioperative pulmonary embolism.Age, limited organ function and high-risk of thrombosis are the main reasons for the low conversion rate.

Platelet Removal Efficiency by Leukocyte Filter in Red Blood Cell Units at Different Storage Periods / 中山大学学报(医学科学版)

ObjectiveThe aim of this study is to investigate change of platelet count in red blood cell （RBC） units at different storage periods and explore the efficiency of platelet removal by leukocyte filter. MethodsA total of 58 RBC units were divided into four groups according to different storage periods： 1 week Group （16）， 2 weeks Group （16）， 3 weeks Group （14） and 4 weeks Group （12）. RBC units in the four groups were filtered through leukocyte filter. The RBC samples before and after filtration were obtained. The platelet count was detected by automatic blood cell counter and the efficiency of platelet removal was calculated. RBC samples before filtration were made into blood cell smears. The blood cell smears were dyed with Wright-Giemsa stain， and the morphology of platelets was observed through a microscope. ResultsThe platelet count in RBC units stored for 1， 2， 3 and 4 weeks was （286.5±62.34）×109/L， （238.0±57.37）×109/L， （193.6±56.21）×109/L and （167.8±24.76）×109/L， respectively. Platelet count in blood stored for 3 weeks （P<0.01） and 4 weeks （P <0.000 1） were significantly lower than those stored for 1 weeks. When observed in the blood smears of RBC units at different storage periods， platelets with normal morphology were distributed in clump and scattered style. The platelet removal rates of the four groups were （80.13±9.06） %， （76.41±10.13） %， （77.78±9.30） % and （70.63±9.39） %， respectively， with no significant difference （P >0.05）. ConclusionsPlatelet count in RBC units decreases gradually as the storage period increases， but most platelets still remain in RBC units of late storage periods （3 weeks and 4 weeks）. The leukocyte filter is able to remove most of the platelets， and the removal efficiency is similar among the groups.

Selection of sterilizing-grade filter for preparation of human coagulation factor Ⅷ/ von Willebrand factor complex / 中国输血杂志

【Objective】 To screen the sterilizing-grade filters applicable for production of human coagulation factor Ⅷ/von Willebrand factor complex(FⅧ/VWF)and study the sterilization filtration process. 【Methods】 Four sterilizing-grade filters for FⅧ/VWF were evaluated through indicators such as filtration capacity, filtration flux, recovery rate of FⅧ activity, recovery rate of VWF activity, recovery rate of VWF antigen, recovery rate of protein and VWF molecular distribution. The sterilizing-grade filter with the best filtration performance was selected for further study. The study was designed by general full-factor design to determine the appropriate filitered protein concentration and filitered speed range through evaluating the total filtered protein amount, recovery rate of protein and filtration efficiency, and then the process operation parameters was determined. 【Results】 The filtration flux of Sartobran P, Sartopore 2 XLG, Sartopore Platinum and Sartopore 2 XLI were 1.71±0.01, 1.80±0.01, 1.34±0.01, and 1.81±0.04 L·(m2)-1·min-1, respectively; the recovery rates (%) of FⅧ activity were 97.09±2.82, 99.22±0.99, 96.87±1.85 and 93.76±1.21, respectively; the recovery rates (%) of VWF activity were 98.12±1.42, 99.95±1.85, 94.80±1.62 and 92.09±1.67, respectively. Between Sartopore 2 XLG and Sartobran P, the difference of filtration flux (P<0.001) was statistically significant; between Sartopore 2 XLG and Sartopore Platinum, the differences of the filtration flux (P<0.001) and VWF potency recovery rate (P<0.05) were statistically significant; between Sartopore 2 XLG and Sartopore 2 XLI, the differences of FⅧ potency recovery rate (P<0.01) and VWF potency recovery rate (P<0.01) were statistically significant. The optimal process operating space of Sartopore 2 XLG was protein concentration of 0.45-0.58 mg/mL, and filtration rate of 1.48-2.95 L·(m2)-1·min-1. 【Conclusion】 Sartopore 2 XLG is the most suitable filter for the production of FⅧ/VWF and the DoE test proves that it has good process operation space.

Simultaneous determination of six aniline compounds in workplace air by high performance liquid chromatography / 中国职业医学

Objective To establish a high performance liquid chromatography (HPLC) method for simultaneous determination of six aniline compounds (ADs) in workplace air. Methods GDH-1 air sampling tube was used to collect six co-existing ADs such as aniline, o-toluidine, N-methylaniline, m-methylaniline, p-methylaniline and N,N-dimethylaniline in the vapor and aerosol of workplace air. The samples were desorbed and eluted using a methanol solution containing 1.00% ammonia water, followed by separation on a C18 chromatographic column and detection using a diode array detector. Results The quantification range of the method was 0.19 -253.50 mg/L, with the correlation coefficient of 0.999 9 for all six ADs. The minimum detection range was 0.02-0.06 mg/m3, and the minimum quantitation range was 0.04-0.19 mg/m3 [both calculated for a 15.0 L sample with a desorption (elution) solution volume of 3.00 mL]. The average desorption and elution efficiencies were 92.15%-104.41% (silica gel) and 94.29%-104.29% (filter membrane). The intra-assay relative standard deviation (RSD) ranged from 0.90%-9.72% (silica gel) and 0.57%-6.96% (filter membrane). The inter-assay RSD ranged from 2.03%-9.78% (silica gel) and 2.50%-8.62% (filter membrane). The samples were stable at room temperature for seven days. Conclusion This method can be used for the simultaneous determination of six ADs in workplace air.

Comparison of patient satisfaction with red-free (green) versus yellow light using binocular indirect ophthalmoscope for retinal examination

Purpose: Comparison of patient satisfaction with red?free (green) versus yellow light using binocular indirect ophthalmoscope for retinal examination. Methods: This is an observational questionnaire?based study of 100 myopes in the age group of 18–40 years coming for a routine check?up or for refractive surgery workup. The examination was done using an indirect ophthalmoscope and a 20D lens with green or yellow light and was assigned in two groups randomly using the coin toss method, following which, a questionnaire was used to assess the following parameters: a) level of comfort, b) any complaints of discomfort during examination, d) preference of the used light source in future, e) grading of discomfort on a linear scale, and f) patient cooperation and duration of examination. Results: Patients were randomized for observation with IDO using either green light (n = 55) or yellow light (n = 45) filter. In the study, 46 patients (83.6%) were very comfortable and only 9 patients (16.4%) experienced mild discomfort when using red?free (green) light, while only 3 patients (6.7%) were very comfortable and 31 (68.9%) had mild discomfort when using yellow light. The complaints of watering with yellow and green light were noted in 36 patients (80.0%) and 15 patients (27.3%), pain in 13 patients (28.9%) and 3 patients (5.5%), light sensitivity in 29 patients (64.4%) and 4 patients (7.3%), respectively, all being significantly more in yellow light category (P < 0.001). The time of examination was significantly more in yellow light category with 83 ± 10.75 seconds (P < 0.001). Conclusion: Retinal examination using the green filter of indirect ophthalmoscope is more comfortable in examining the patients as compared to routine yellow light with decreased number of complaints, lesser examination time, and better patient cooperation.

Assessing contrast sensitivity change in retinal diseases with use of yellow-amber NoIR glasses

Purpose: The purpose of this study was to assess change of contrast sensitivity (CS) in subjects having retinal diseases with yellow?amber no infrared (NoIR) glasses used as low vision aid (LVA). Methods: We examined CS in 82 low vision (LV) subjects having retinal diseases with Pelli Robson Chart at 1 m distance before and after wearing yellow?amber NoIR glasses. We also found type of retinal affection and macular optical coherence tomography (OCT) features. Results: The distance and near best?corrected visual acuity (BCVA) was, respectively, 0.68 ± 0.17 (median = 0.70) and 0.72 ± 0.25 (median = 0.70) logmar units. The pre?LVA CS was 0.52 ± 0.29 (median = 0.3) and post? LVA was 0.52 ± 0.28 (median = 0.45) logunits (mean reduction = ?0.002 ± 0.24; Median reduction = 0; P = 0.909). The pre?LVA and post?LVA CS showed a negative correlation with logmar distance BCVA [r = ?0.090; P = 0.317 and r = ?0.152; P = 0.090 respectively]. The pre?LVA and post?LVA CS showed a negative correlation with logmar near BCVA [r = ?0.114; P = 0.207 and r = ?0.054; P = 0.549 respectively]. The CS did not improve in subjects having macular degeneration, pathological myopia, hereditary maculopathy, and diabetic retinopathy. The macular OCT features like fluid, exudates, scars, drusens, traction, and hole did not significantly influence CS both at pre?LVA and post?LVA stage. Conclusion: This is the first study with yellow?amber NoIR glasses which blocks “both ultraviolet and infrared light.” The subjects having macular degeneration, pathological myopia, hereditary maculopathy, and diabetic retinopathy did not improve in CS with filters. The correlation values showed that filters may improve CS in subjects having good baseline BCVA.

Follow control of upper limb rehabilitation training based on Kinect and NAO robot / 生物医学工程学杂志

Gesture imitation is a common rehabilitation strategy in limb rehabilitation training. In traditional rehabilitation training, patients need to complete training actions under the guidance of rehabilitation physicians. However, due to the limited resources of the hospital, it cannot meet the training and guidance needs of all patients. In this paper, we proposed a following control method based on Kinect and NAO robot for the gesture imitation task in rehabilitation training. The method realized the joint angles mapping from Kinect coordination to NAO robot coordination through inverse kinematics algorithm. Aiming at the deflection angle estimation problem of the elbow joint, a virtual space plane was constructed and realized the accurate estimation of deflection angle. Finally, a comparative experiment for deflection angle of the elbow joint angle was conducted. The experimental results showed that the root mean square error of the angle estimation value of this method in right elbow transverse deflection and vertical deflection directions was 2.734° and 2.159°, respectively. It demonstrates that the method can follow the human movement in real time and stably using the NAO robot to show the rehabilitation training program for patients.

Automatic removal algorithm of electrooculographic artifacts in non-invasive brain-computer interface based on independent component analysis / 生物医学工程学杂志

The non-invasive brain-computer interface (BCI) has gradually become a hot spot of current research, and it has been applied in many fields such as mental disorder detection and physiological monitoring. However, the electroencephalography (EEG) signals required by the non-invasive BCI can be easily contaminated by electrooculographic (EOG) artifacts, which seriously affects the analysis of EEG signals. Therefore, this paper proposed an improved independent component analysis method combined with a frequency filter, which automatically recognizes artifact components based on the correlation coefficient and kurtosis dual threshold. In this method, the frequency difference between EOG and EEG was used to remove the EOG information in the artifact component through frequency filter, so as to retain more EEG information. The experimental results on the public datasets and our laboratory data showed that the method in this paper could effectively improve the effect of EOG artifact removal and improve the loss of EEG information, which is helpful for the promotion of non-invasive BCI.

A makeshift blue light filter for endoscopic identification of traumatic cerebrospinal fluid leak using fluorescein

Objective@#To describe a makeshift blue light filter for endoscopic visualization of a traumatic cerebrospinal fluid leak repair using intrathecal fluorescein and its application in one patient.@*Methods@# Study Design:Surgical Instrumentation Setting:Tertiary Government Training Hospital Patient:One @*Results@#Intra-operative endoscopic identification of fistulae sites was achieved using intrathecal injection of fluorescein that fluoresced using our makeshift blue light filter in a 43-year-old man who presented with a 3-month history of rhinorrhea due to skull base fractures along with multiple facial and upper extremity fractures he sustained after a fall from a standing height of 6 feet. He underwent transnasal endoscopic repair of cerebrospinal fluid fistulae in the planum sphenoidale, clivus and sellar floor. Post-operatively, there was complete resolution of rhinorrhea with no complications noted. @*Conclusion@#Our makeshift blue light filter made from readily available materials may be useful for endoscopic identification of CSF leaks using fluorescein in a low- to middle-income country setting like ours.

Determination of tin and its compounds in ambient PM2.5 by atomic fluorescence spectrometry after ultrasonic extraction with concentrated hydrochloric acid / 环境与职业医学

Background Tin and its compounds can cause serious harm to human respiratory system and nervous system, but there is no corresponding national standard method for the determination of tin in PM2.5. Objective To establish a method for the determination of tin and its compounds in PM2.5 by atomic fluorescence spectrometry (AFS) after ultrasonic extraction with concentrated hydrochloric acid. Methods We extracted a fixed volume of air at a constant speed through a sampler with preset cutting characteristics to trap PM2.5 in the ambient air on quartz filter membranes. By selecting extraction solvent, comparing extraction temperature and time, and adjusting the acidity of solution to be measured, the sample pretreatment process was optimized, and a method for the determination of tin and its compounds in PM2.5 by AFS was proposed, and its performance indexes such as linearity, detection limit, and lower limit of quantification were obtained. The accuracy and precision of the method were evaluated by the standard addition recovery test with blank quartz filter membranes, and the interference test was carried out by adding standard urban particulate samples. The proposed method and the method recommended by the “Handbook on Monitoring and Protection of Air Pollution (Haze) Effects on Population Health (2020)” (the Handbook) were applied to actual samples, and the results were compared. Results This experiment used concentrated hydrochloric acid as the extraction solvent. The higher the reaction temperature and the longer the reaction time, the higher the recovery rate. Therefore, 70 ℃ water bath ultrasonic extraction for 3 h was selected. In terms of the proposed method, the linear range of detection was from 5.00 μg·L−1 to 50.00 μg·L−1, with a correlation coefficient ≥0.999 and a detection limit of 0.27 μg·L−1. When the quantitative detection of the lower limit was 0.90 μg·L−1，and the sampling volume was 144 m3, the limit of quantification was 1.25 ng·m−3. The recovery rate of standard addition of blank quartz filter membranes was 94.1%-97.5%, with a relative standard deviation ≤3.2%; the recovery rate of standard addition of standard urban particulate matter samples was 93.5%-103.0%, and the relative standard deviation was ≤2.1%, indicating that coexisting components in PM2.5 samples would not affect the determination of tin. For the 10 quartz filter membrane samples of PM2.5 monitoring, the results of tin by the established method (extraction with concentrated hydrochloric acid) were higher than those of the Handbook recommended method (extraction with nitric acid), and the difference is (3.61±0.54) ng·m−3(t=21.303, P<0.05). Conclusion The established method for the determination of tin and its compounds in PM2.5 by AFS after ultrasonic extraction with concentrated hydrochloric acid is simple, accurate, and suitable for laboratory determination of tin and its compounds in large quantities of PM2.5 samples.

Distal embolic filter protection during debulking treatment of peripheral artery disease / 中华普通外科杂志

Objective:To discuss the strategies of distal embolic filter protection(DEFP) during excimer laser ablation (ELA) or percutaneous mechanical thrombectomy (PMT) in treatment of peripheral artery disease.Methods:Clinical data of 29 patients undergoing ELA or PMT under the DEFP from Oct 2019 to Aug 2021 were retrospectively collected to analyze the strategies of DEFP and high-risk factors of capturing clinically significant macrodebris.Results:There were 21 males and 8 females, aged (70.3±11.0) years with 32 lesions (29 limbs) including 5 in-stent restenosis (ISR), 10 thrombosis and 17 chronic total occlusion (CTO). The technical success rate of DEFP device release and recovery was 100%. The overall debris capture rate was 77.3% and the macrodebris capture rate was 36.4%. Even with DEFP the distal embolization (DE) incidence was 3.4%. When ELA for CTO with severe calcification or long-segment ISR lesions, the capture rate of macrodebris was as high as 60.0%, and the former was significantly higher than ELA for CTO without high calcification lesions ( P<0.05). Conclusion:ELA or PMT under the DEFP in treatment of peripheral artery disease appears to be of great significance in preventing DE.

Effects of flattening filter on dosimetry in fractionated stereotactic radiotherapy for brain metastases / 中国辐射卫生

@#<b>Objective</b> To investigate the dosimetric differences between volumetric modulated arc therapy (VMAT) with a flattening filter (FF) and flattening filter-free (FFF) VMAT in fractionated stereotactic radiotherapy for brain metastases. <b>Methods</b> Seventeen patients with brain metastases were divided into FF-VMAT group (VMAT plans with the FF mode) and FFF-VMAT group (VMAT plans with the FFF mode). The two groups were compared in terms of target volume dose parameters (<i>D</i>_98%, <i>D</i>_2% and <i>D</i>_mean), the conformal index (<i>CI</i>), the gradient index (<i>GI</i>), the gradient, normal brain tissue dose parameters (<i>V</i>_5Gy, <i>V</i>_10Gy, <i>V</i>_12Gy and <i>D</i>_mean), monitor units, and beam-on time. <b>Results</b> Compared with the FF-VMAT group, the FFF-VMAT group had significantly lower <i>GI</i> (3.33 ± 0.37 <i>vs</i> 3.27 ± 0.35, <i>P</i> = 0.001), a significantly lower gradient [(0.85 ± 0.20) cm <i>vs</i> (0.84 ± 0.19) cm, <i>P</i> = 0.002], a significantly shorter beam-on time [(177.05 ± 62.68) s <i>vs</i> (142.71 ± 34.59) s, <i>P</i> = 0.001], and significantly higher <i>D</i>_2% [(65.69 ± 2.15) Gy <i>vs</i> (66.99 ± 2.03) Gy, <i>P</i> = 0.001] and <i>D</i>_mean [(58.77 ± 1.60) Gy <i>vs</i> (59.95 ± 1.43) Gy, <i>P</i> <0.001]. There were no significant differences in the <i>CI</i>, the<i> D</i>_98%of the target volume, the <i>V</i>_5Gy, <i>V</i>_10Gy, <i>V</i>_12Gy and <i>D</i>_mean of the normal brain tissue, and monitor units between FFF-VMAT and FF-VMAT. <b>Conclusion</b> FFF-VMAT can better protect the normal tissue around the target volume, reduce the beam-on time, and improve treatment efficiency.