In the bioelectric measurement, the electrode impedance detection is an important index to the signal quality evaluation and sensor electrode contact condition. In this paper, a method of accurately measuring the electrode impedance based on EEG measurement system was put forward, the method is based on the constant current source excitation signals which are added to the human body, by monitoring the human voltage to measure the electrode impedance. And different reference resistor calibration calculation in different sections was used to reduce the effect of constant current source on the precision of measurement results to improve the measurement accuracy.
Calibration ; Electric Impedance ; Electroencephalography

By studying of the pathology of human sleep and respiration disorder diseases, the method of sleep and respiration measurement, the evaluation index, a kind of micro sleep monitor and evaluation system was designed. Based on the methods of spectrum absorption and force changing, using high performance pulse oxygen saturation monitoring technology and respiration monitoring technology, developing a low-cost, high usability sleep monitor system which is convenience for family using. It can measure the signal of human oxygen saturation and chest respiration, can improve the quality of signal and reliable from arithmetic and sensor installing.
Humans ; Monitoring, Physiologic ; instrumentation ; methods ; Oximetry ; instrumentation ; methods ; Respiration ; Sleep ; physiology ; Software Design

Objective To explore the effects on image quality and dose reduction to the lens when using bismuth shielding in head and neck MSCT.Methods The standard phantom and the cadaveric head with none,1,2 and 3 layers of bismuth shielding were scanned with protocols of brain,temporal bone and paranasal sinuses using a 16-MDCT scanner.The organ dose to the lens in each scanning was measured with thermoluminescence dosimeters(TLD).The above scanning with sinus protocol was repeated with a sponge with thickness of 5,10,15 and 20 mm placed between the shielding and phantom/head.The CT attenuation of phantom with the distance of 2,4,6 and 8 cm to shielding were measured.The image quality was subjectively evaluated by 2 physicians.Results The organ doses of the lens with protocols of brain,temporal bone and sinuses were 24.31,27.60 and 20.01 mGy,respectively.The doses were decreased significantly when using bismuth shielding.With the increase of the shield gap,the degree of dose reduction was reduced,but the increasing degree of CT attenuation significantly reduced.Using 2-layer and 3-layer bismuth shield in brain and temporal bone CT scan,the radiation doses were reduced by 47.1％ and 59.1％,respectively while maintaining the diagnostic image quality.Using 1-layer shield without gap and 2-layer shield with 1.5 cm gap in sinus CT,the radiation doses were reduced by 31.5％ and 34.5％,respectively.Conclusions Reasonable usage of bismuth shielding can effectively reduce the radiation dose to the lens of eye in head and neck MSCT.

Objective To investigate the condition and the related influence factors of small airway function in controlled bronchial asthmatic children.Methods Children diagnosed with bronchial asthma controlled,aged 5-14 years old without gender limitation were consecutively enrolled.Survey questionnaire including asthma symptoms in the past one month and medication usage were conducted.Physical condition and lung function were examined.Results A total of 255 patients were included in this study,and 224 patients had normal small airway function in which the level of forced expiratory flow at 50％ of forced vital capacity(FVC) exhaled (FEF50),forced expiratory flow at 75％ of FVC exhaled(FEF75),maximal mid-expiratory flow(MMEF) was 87.9％ (77.0％,97.2％),73.8％ (65.6％,93.5％),and 84.9％ (76.4％,97.5％) of the predicted value,respectively.Thirty-one patients had small airway dysfunction,accounting for 12.2％ (31/255 cases),and the level of FEF50,FEF75,MMEF were 62.8％ (59.9％,65.5％),51.9％ (46.6％,55.5％),and 62.7％ (57.2％,64.4％) of the predicted value,in which FEF75 had shown more decrease than others.In small airway dysfunction group,10 patients had conducted bronchodilation testing,and improvement rate of FEF50,FEF75 and MMEF were 41.1％,47.5％ and 41.3％,and all 10 cases (100.0％) returned to normal level.No significant difference was found in gender,body mass index,atopy,disease duration,drug usage between 2 groups (all P ＞ 0.05).Conclusion In 5-14 controlled asthmatic children,12.2％ have small airway dysfunction with a certain degree of reversibility.Gender,body mass index,atopy,disease duration,drug usage are not influencing factors.

OBJECTIVE:To establish a method for simultaneous determination of 6 components in Niuhuang ninggong tablets.METHODS:HPLC method was adopted.The determination was performed on TC-C18 column with mobile phase consisted of methanol-0.05％ phosphate acid (gradient elution) at the flow rate of 1.0 mL/min.The detection wavelength was set at 280 nm,and the column temperature was 25 ℃.The sample size was 10 μL.RESULTS:The linear ranges of glycyrrhizin,berberine hydrochloride,baicalin,baicalin,emodin and chrysophanol were 3.2-320 μg/mL(r=0.999 9),8.8-880 μg/mL(r=0.999 8),5.6-560 μg/mL (r=0.999 5),2.0-200 μg/mL(r=0.999 9),4.4-440 μg/mL (r=0.999 9),2.0-200 μg/mL(r=0.999 7),respectively.RSDs of precision,stability and reproducibility tests were all lower than 6.0％.The recoveries were 96.34％-97.25％ (RSD=0.33％,n=6),96.12％-98.06％ (RSD=0.82％,n=6),96.36％-99.09％ (RSD=1.02％,n=6),95.84％-97.32％ (RSD=0.65％,n=6),95.83％-97.92％(RSD=0.88％,n=6),98.60％-99.65％(RSD=0.42％,n=6),respectively.CONCLUSIONS:The method is simple,accurate,stable and reproducible,and can be used for content determination of 6 components in Niuhuang ninggong tablets.

Objective To explore the effectiveness of impulse oscillometry(IOS)in airway responsiveness measurement and to find out the positive threshold of IOS for asthma diagnosis. Methods Seventy-nine children aged 6-14 years who had suspicious asthma,were recruited into the study. The positive criteria of the methacholine bron-chial provocation test was a 20％ reduction in forced expiratory volume in the first second (FEV 1 )compared to base-line. Simultaneously measured changes in various parameters of IOS,including resonant frequency(Fres),impedance at 5 Hz(Zrs),resistances at 5 and 20 Hz(R5,R20),reactance at 5 Hz(X5),and area of reactance(AX). The results of the challenge test were divided into positive and negative groups according to the pulmonary ventilation function me-thod. The differences between the 2 groups of IOS parameters before and after the challenge test,and the correlation be-tween the change rate of FEV1 and the change rate of IOS parameters were compared,and the positive judgment criteria of IOS parameters in the determination of respiratory responsiveness were determined. Results The positive group of bronchial provocation test had 37 patients and negative group had 42 patients. There was no significant difference in the basic values of parameters between the positive group and the negative group (all P > 0. 05). Changes in Zrs,R5,X5 of IOS were correlated with changes in FEV1 (r = 0. 374,0. 310,0. 449,all P < 0. 05). By single factor analysis,the area under the receiver operating characteristic(ROC)carve (AUC)showed:basic value of Zrs increased by 45. 85％,R5 increased by 45. 72％,X5 increased by 80. 74％ respectively compared to the baseline showed the optimal combination of sensitivity and specificity. In multivariate Logistic regression models,when Zrs and R5 were combined to measure the airway responsiveness,the sensitivity and specificity were 73. 0％ and 81. 0％,respectively. Conclusions IOS and spirometry can be used to determine airway responsiveness in children during methacholine bronchial challenge. Zrs≥45. 85％,or R5≥45. 72％,or X5≥80. 74％,or Zrs and R5 of multiple regression formula can be used as the positive criteria for young children with airway heperresponsiveness,the combination of Zrs and R5 has higher sensitivity and specificity.

Objective:To investigate the effect of different additional filters on the image quality and radiation dose in abdominaldigital radiography (DR).Methods:Retrospective analysis was performed on 10 cases of abdominal DR from December 2020 to January 2021 in Fuxing Hospital, and the average mAs was calculated. Using automatic exposure control (AEC) technology, a polymethyl methacrylate (PMMA) slab of the corresponding thickness (18 cm) at the same output of above mAs was confirmed and used as the attenuator to simulate the abdomen. The phantom of CDRAD 2.0 and 17 slices of 10 mm thick PMMA plates (total thickness 18 cm) were placed on the bed. The additional filters were selected as no additional filter, 2 mmAl, 0.1 mmCu+ 1 mmAl, 0.1 mmCu+ 2 mmAl respectively. The AEC levels were selected at -2, -1, 0, 1, and 2 respectively. The images were collected and analyzed by using CDRAD 2.0 software to obtain the image quality factor (IQF inv). The incident air kinetic energy on the surface of the PPMA was measured for each exposure, and PCXMC software was used to estimate the organ dose and effective dose, and a comparative analysis was made. Results:The skin incident doses at no additional filter, 2 mmAl, 0.1 mmCu+ 1 mmAl, 0.1 mmCu+ 2 mm Al were (0.546 1±0.200 8), (0.376 2±0.133 8 ), (0.285 3±0.100 1) and (0.289 9±0.099 2) mGy, respectively. The estimated effective doses were (79.63±29.24)×10 -3, (71.05±25.56)×10 -3, (63.58±22.18)×10 -3 and (67.64±23.11)×10 -3 mSv, respectively. The gonadal doses were (0.058 1±0.020 8), (0.050 0±0.018 0), (0.044 8±0.015 6) and (0.047 7±0.016 3) mGy.The IQF inv values were 4.70±0.61, 4.80±0.84, 4.60±0.55, 4.60±0.60, respectively. There were linear correlations between the effective dose and the skin incident dose under different additional filtration, and the effective doses increased with the increase of the incident doses. The dose was lowest at the addition filtration of 0.1 mmCu+ 1 mmAl. There was no significant difference in the IQF inv between groups( P>0.05). Conclusions:The optimal additional filtration for abdominal DR was 0.1 mmCu+ 1 mmAl with the image quality meeting the requirements of clinical diagnosis, the radiation dose reduced reasonably, and the objective of the optimization of radiographic parameters achieved.

Biofilms are complex three-dimensional bacterial assemblages that attach to biotic or abiotic solid surfaces, and frequently embed within a self-produced matrix of extracellular polymeric substances. Biofilm formation is a microbial defense response to biotic and abiotic stresses, and a key factor for survival in adverse environments. A wide variety of microorganisms can colonize distant tissues of higher plants, such as leaves, vascular network and roots, and adhere to the surface of the tissues to form biofilms. The dynamic processes in forming biofilms in response to plant internal environment are key steps required for full virulence of phytopathogenic bacteria. Exploring the mechanisms involved in regulation of bacterial biofilms is important for understanding the plant-pathogens interactions. In this review, we summarized the research progresses related to the biofilms of bacterial phytopathogens, including biofilm characteristics, essential regulatory mechanisms and key signals affecting the transition between a planktonic lifestyle and multicellular behavior.

Objective:To explore the level of fractional exhaled nitric oxide (FeNO) in preschool children in Beijing and analyze the influencing factors.Methods:Preschool students aged 3-5 in Beijing were selected from May to July 2017.Healthy children were screened through questionnaire survey and on-site physical examination, and their FeNO levels were detected.Results:A total of 317 healthy children were enrolled, including 161 males and 156 females.There was no significant difference in FeNO levels between different genders ( P>0.05). The geometric mean value of FeNO was 8.2 ppb in male(95% CI: 7.0-9.3 ppb)and 8.7 ppb in female (95% CI: 7.4-10.1 ppb). There were statistical differences in FeNO levels among the 3 age groups ( F=4.63, P<0.05). The geometric mean value of FeNO was 7.2 ppb in 3-year-old children (95% CI: 5.5-8.9 ppb), 8.8 ppb in 4-year-old children (95% CI: 7.4-10.2 ppb), and 9.2 ppb in 5-year-old children (95% CI: 7.7-10.7 ppb). The geometric mean value of FeNO of healthy preschool children was 8.5 ppb (95% CI: 7.6-9.3 ppb). There was a positive correlation between FeNO and height ( r=0.135, P<0.05), but there was no significant correlation between FeNO and weight. Conclusions:The geometric mean value of FeNO in healthy preschool children in Beijing is 8.5 ppb (95% CI: 7.6-9.3 ppb)and the 95% reference value is 23.5 ppb.The level of FeNO changes slightly with the increase of age, and height also affects the FeNO.It is highly feasible to use on-line tidal breathing method to measure FeNO of preschool children.

The high-pass filter which is designed to overcome the polarization voltage in the ECG measurements can affect the measurement of the ST-segment; but the accuracy of the ST-segment will have an impact on the diagnosis and treatment of heart diseases. This paper used the ECG detection platform to test the effect of the high-pass filter at different frequency and studied the effect of the high-pass filter on the ST segment to ensure proper use of different application modes.
Electrocardiography ; instrumentation ; methods ; Filtration