BACKGROUND:The electrical impedance tomography (EIT) is a kind of examination that is used to non-invasively measure the change and distribution of electrical bio-impedance by reconstructing the frequency response obtained by electrical stimuli applied onto the human body. The characteristics of impedance of any tissues are of great importance to the imaging of EIT and locating and monitoring the lesion focus.OBJECTIVE: To measure the human brain impedance in the frequency range from 0.1 Hz to 1 MHz and to compare these with those of other human tissues and the rabbit brain tissues.DESIGN: An observational experiment.SETTING:The Department of Medical Electric Engineering of the Biomedical Engineering College of the Fourth Military Medical University of Chinese PLA.MATERIALS:The experiment was conducted at the Otolaryngology Laboratory, Department of Medical Electric Engineering of Biomedical Engineering College, Fourth Military Medical University of Chinese PLA from April, 2000 to June, 2000. Two brains were harvested from two cadavers of adult men who died in less than 12 hours before the brains were taken.INTERVENTIONS :The brains were divided into 15 samples and the Solartron 1255B frequency resoonse analyzer was used to measure the complex impedance of human brain in vitro with four-electrode measurement method in the frequency range from 0.1 Hz to 1 MHz.There were also impedance interface (1294)and self-made experimental measurement box.MAIN OUTCOME MEASURES:The resistivity frequency response,curves of real part and imaginary part of complex impedance as well as the equivalent circuit model of the complex impedance.RESULTS:The resistivity of human brain tissues was about 1 200 Ω·cm in the frequency range of 0.1-100 Hz.But it decreased to 650 Ω·cm in the frequency range of 100-1×106 Hz. The real part of complex impedance remained steady in the frequency range of 0.1-100 Hz and it decreased along with the increase of frequency in the range of 100-1×106 Hz. The absolute value of frequency response curves of the imaginary part of human brain's complex impedance presented a tendency of monotonic increase.CONCLUSION: The resistivity and the real part of complex impedance curve of human brain were in accordance with those of other tissues such as muscles, the liver, kidney and lungs. The frequency response curve of the imaginary part of human brain's complex impedance was different from that of other animal tissues (such as muscles, the liver and kidney) but was in accordance with that of rabbit brain tissues in vitro. The construction of the equivalent circuit model obtained was more complex than other models known.

BACKGROUND: Electrical impedance tomography (EIT) uses non-invasive signals to probe the human body and then detect the responses on the boundary of the body in order to reconstruct an impedance distribution inside the body. Compared to CT and MRI, EIT takes the advantages of realtime technique, lower cost and easiness for both continuous monitoring and functional imaging.OBJECTIVE: This study was designed to perform the in vivo measurement of the rabbit brain impedance frequency response before and after ischemia. And it was to verify the feasibility of EIT in brain functional imaging by ischemia brain functional imaging using EIT.DESIGN: It was a single-sample experiment.SETTING: It was conducted at the Department of Medical Electronic Engineering, Faculty of Biomedical Engineering, Fourth Military Medical University of Chinese PLA.MATERIALS: This study was conducted at the Department of Medical Electronic Engineering, Faculty of Biomedical Engineering, Fourth Military Medical University of Chinese PLA from August to September 2001 and 10 healthy rabbits were selected.METHODS: Cerebral ischemia animal model was made using carotid artery ligation. Then the in vivo measurement of the rabbit brain impedance frequency response before and after ischemia was performed.Dynamic unilateral brain blood supply was recorded using EIT imaging.curves were plot before and after ischemia in the frequency range from 0.1 Hz EIT imagingRESULTS: Nine rabbits entered the statistical analysis and one was omitimpedance increased significantly. The ratio of increasing impedance can be up to 75% at frequencies lower than 10 Hz. And in the range from 1 kHz namic imaging showed that the changes in unilateral brain blood supply is accordant with the corresponding regions having a changing impedance.CONCLUSION: The changes in brain tissue impedance before and after ischemia can be imaged and it could be used as a variable for EIT imaging.

Objective To investigate the distribution and antimicrobial susceptibility of the bacteria isolated from bloodstream infections during 2013-2014 in Changhai Hospital for rational use of antibacterial agents.Methods The bacterial strains from blood samples were collected during the period from January 2013 through December 2014,and subjected to antimicrobial susceptibility testing by using automated system or Kirby-Bauer method.The results were interpreted according to CLSI M100-S24 breakpoints or FDA breakpoints.The data were analyzed by WHONET 5.6 software.Results A total of 1 048 nonduplicate isolates were collected,of which Escherichia coli,coagulase-negative Staphylococcus (CNS) and Klebsiella pneumoniae accounted for 29.5％,15.8％ and 13.8％,respectively.Gastroenterology,Hematology,General surgery,Urology and Department of Infectious Diseases are the top 5 departments according to their total number of bacterial isolates.The results of antimicrobial susceptibility testing showed that ESBLs-producing E.coli and K.pneumoniae accounted for 63.8％ and 38.6％,respectively.The prevalence of methicillinresistant CNS (MRCNS) was 77.6％.The E.coli strains isolated from Urology showed higher resistance rates to cephalosporins than the total E.coli strains,while the E.coli strains isolated from Gastroenterology showed higher resistance rates to betalactarn/beta-lactamase inhibitor combinations and carbapenems than the total E.coli strains.Higher prevalence of MRCNS was found in departments of Hematology,Urology and Neurosurgery.All the CNS strains isolated from Neurosurgery were resistant to methicillin.The K.pneumoniae strains isolated from Bum ICU had higher resistance rates to all the antibacterial agents tested than the total K.pneumoniae strains,while the K.pneumoniae strains isolated from Gastroenterology showed higher resistance rates to carbapenems and tigecycline than the total K.pneumoniae strains.Conclusions The pathogenic bacteria isolated from bloodstream infections vary with departments in terms of species distribution and antimicrobial susceptibility profile.It is necessary to strengthen the surveillance of antimicrobial resistance in hospital for rational use of antibiotics.

A real time monitoring terminal for the empty nest elderly based on extracting fabric type sensor and acceleration sensor combined with Bluetooth wireless communication technology is proposed. When the system detects arrhythmia and falls of the elderly, and then start the wireless bluetooth communication, complete the information interaction with mobile phone gateway device, so as to implement the rescue.
Cell Phone ; Custodial Care ; methods ; Equipment Design ; Humans ; Monitoring, Ambulatory ; instrumentation ; Signal Processing, Computer-Assisted ; instrumentation ; Telemedicine ; instrumentation

It is the intent of this paper to develop better reconstruction algorithm for electrical impedance tomography (EIT). Simulation study of the reconstruction algorithm based on the sensitivity theorem is made and the reconstruction algorithm is compared with other normal algorithms. The results indicate that sensitivity method as a kind of static reconstruction algorithm has higher accuracy and speed of iteration, so it is worth researching for laboratory modality work.
Algorithms ; Computer Simulation ; Electric Impedance ; Tomography ; methods

Induced-current electrical impedance tomography (ICEIT) is a newly hot research field in electrical impedance tomography (EIT) because of its advantages of contactless exciting. A preliminary ICEIT system with 3 excitation coils has been accomplished. It includes the constant current source (CCS), power amplifiers, excitation coils,physical phantom, measurement-mode setting circuit, signal measuring block, DAC and digital I/O card. The CCS is accomplished with Direct Digital Synthesis (DDS) technique. Its frequency is 46.875 KHz. Its output current is divided into 16 steps from 0.16 mA to 2.56 mA which can be set by computer. The three driving coils have the same diameter of 50 cm, each coil's inductance is 193.5 microH. The power amplifier can provide 800 mA driving current (f = 46.875 KHz) to the coil under +/- 25 V power supplying. The signal from measurement electrodes is switched to measurement channel which includes IA, BP filter and synchronized demodulator, then the analog signal is converted to digital signal by a 12b A/D Card and the data is acquired by DMA mode. Our experiments show that a distinguish change of signal from the surface electrodes can be acquired by the experimental system when different objects are placed in the physical phantom. And 3 x 31 signals for preliminary imaging have been acquired.
Algorithms ; Amplifiers, Electronic ; Electric Impedance ; Electrodes ; Electromagnetic Fields ; Electromagnetic Phenomena ; instrumentation ; Humans ; Image Processing, Computer-Assisted ; Phantoms, Imaging ; Tomography ; instrumentation ; methods

The complex impedance measurements of human brain tissue in vitro are made by using four-electrode measurement methods in the frequency range from 0.1 Hz to 1 MHz. The Solartron 1255 B frequency response analyzer is used. The frequency response curves of the imaginary part of human brain's complex impedance do not appear as a single peak curve which other bio-tissues show, and the Cole-Cole diagram of human brain is different from the others as well. The construction of the equivalent circuit model obtained is more complex. However, these characteristics of human brain are all the same as rabbit brain's. The equivalent circuit model obtained will be helpful to constructing the equivalent circuit model of human head in the EIT researches.
Adult ; Brain ; physiology ; Electric Impedance ; Electrodes ; Humans ; In Vitro Techniques ; Male ; Models, Biological

Objective To understand the cleaning quality of dental handpieces in Suzhou City, analyze the relevant factors that influencing cleaning effect.Methods A cross-sectional study was performed with the proportional system sampling method, questionnaires were adopted to investigate the cleaning location, cleaning method and process of dental handpieces, the ATP fluorescence detection method was conducted to detect cleaning quality.Results In 10 administrative regions of this city, a total of 72 medical institutions were selected, 25 were public medical oral diagnosis and treatment institutions, 47 were private clinics.Cleaning effect of automatic handpiece cleaning machine was better than traditional manual cleaning (unqualified rate :3.95% vs 11.96%, P<0.05), unqualified rate of handpieces cleaned by cleaning personnel without inadequate knowledge was higher than that by personnel with adequate knowledge(14.88% vs 3.57%, P<0.05).Qualified rate of cleaning: different cleaning locations ranged from 5.00% to 11.23%, cleaning equipment was inadequate and sufficient 11.89% and 7.29% respectively, cleaning personnel were not designated and designated 12.16% and 9.83% respectively, but the difference were not statistically significant (all P>0.05).The quality of cleaning of handpieces could be improved if waiting time of cleaning ≤30 minutes, enzymes were used during cleaning, and purified water was used at the end rinse(all P<0.05);whether there was drying process and used lubricant, difference were both not significant.Conclusion Using automatic handpiece cleaning machine, cleaning personnel with adequate knowledge, cleaning waiting time ≤30 minutes, enzyme use during the cleaning process, and purified water use at the end rinse can improve the quality of cleaning of dental handpieces.

Objective To explore the cleaning status and cleaning quality of dental handpieces in various types of medical institutions in Suzhou City.Methods On October 26-31, 2015, dental clinics in the whole city were sampled according to cross-sectional survey and proportional sampling method, the cleaning quality of dental handpieces in each clinic was detected by ATP bioluminescence assay.Results 72 medical institutions, 201 handpieces, 402 samples in 10 administrative regions of the city were sampled, 42 samples was unqualified, unqualified rate was 10.45％, unqualified rate of cleaning of dental handpiece surface was higher than waterline of dental handpiece(17.91％ vs 2.99％, P<0.05).Cleaning quality of dental handpieces in different grades of medical institutions was different(P<0.05), tertiary medical institutions were all ualified, medical institutions without grade was 14.45％.According to the classification based on name of different medical institutions, cleaning quality of handpieces was statistically significant(P<0.05), cleaning efficacy of dental handpieces in department of stomatology of public hospitals was best(unqualified rate was 4.31％), while private dental clinics had the worst cleaning efficacy(unqualified rate was 13.81％).Conclusion Education and training of dental handpieces cleaning in the whole city should be strengthened, especially the management of cleaning of dental handpieces in low grade and private dental clinics.

The human skull impedance was quantitatively measured by means of Frequency Response Analyzer and its software. The impedance-frequency response curves of human skull were obtained. By analyzing the curves, we found that the characteristic frequency of human skull should be around 10 KHz.
Adult ; Electric Impedance ; Humans ; Middle Aged ; Skull ; physiology ; Time Factors