Objective The Hilbert- Huang transformation (HHT) method was introduced to process the bio-impedance gastric motility signals from subjects.Methods Nonlinear and non-stationary original gastric motility series were decomposed into a number of intrinsic mode function (1MF) components by the empirical mode decomposition method (EMD).Hilbert transformation was carried out then and instantaneous frequency was extracted effectively.Gastric motility signal among 0.03-0.06 Hz was reconstructed from the IMF.Results The results suggested that HHT was a new and applicable time series analysis method based on mode decomposition and could extract impedance signal and remove the disturbances such as blood flow and breathing.Conclusion The new adaptive mode decomposition-based signal processing method provides a new method to investigate clinical gastric motility information.

OBJECTIVE Toillustratethepharmacokineticsandpharmacodynamicsofdifferentdos-agesofsustained-releaseimplantofgoserelininrats.METHODS Theratsreceivedasingledoseof sustaineed-release i mplant of goserelin 0.3,0.6 and 1 .2 mg per rat by subcutaneous injection,respec-tively.Concentrations of goserelin and testosterone in plas ma were determined by HPLC-MS/MS.The pharmacokineticparameterswerecalculatedbyWinNonlin6.3.RESULTS Themainpharmacokinetic parameters of the 0.3,0.6 and 1 .2 mg per rat were as fowllows:the area under the concentration-time curve(AUC0-t)was 770 ±96,1534 ±299 and (3233 ±777)μg·L-1·h,and the maximum plasma con-centration(cmax)was 3.7 ±0.3,6.8 ±2.2 and (1 7.6 ±5.4)μg·L-1 ,respectively.Regression analysis was applied to analyze the relationship between AUC0-t and cmax at different doses and those relative coefficients were 0.942 and 0.923 respectively.AUC0-t and cmax increased with the dose in the range of 0.3-1 .2 mg per rat.As for other main pharmacokinetic parameters (peak time,half life,mean resi-dence time,clearance and apparent volume of distribution),there was no significant difference between the three groups.Testosterone plasma concentration reached the highest level following administration and then kept decreasing to low concentrations.Between 28 d and 35 d,testosterone plas ma concentra-tionslowlyincreasedtothenormallevel.CONCLUSION Pharmacokineticcharacteristicsofsustained-release implant of goserelin in rats show a linear relationship,within the dose range of 0.3-1 .2 mg per rat.The results from pharmacodynamic data show that testosterone does not change in a dose-depend-ent manner at a dose ranging from 0.3 to 1 .2 mg per rat.Testosterone plasma concentration decreases to theoretical castrate level (0.5 μg·L-1 )after 4 d following a dose of 0.6-1 .2 mg per rat.

Objective To study the phase correlation of cutaneous multichannel impedance measurements and the contractions, peristalsis of stomach and the conduction properties in space.Methods A spiral gastric body model was rotated to simulate shrinkage and creep of the stomach.In order to verify the feasibility and validity of the multichannel impedance gastric dynamic measurement, experiments with emulation of multichannel impedance gastric motility measuring principle were conducted through three-dimensional simulation on the electrical characteristics of gastric body model in saline tank simulator.Results The emulation results showed that the change of epigastric current density and potential distribution is consistent with the course of moving from top to bottom when lateral edge of model (namely the intumescent location when the stomach is full) after detecting electrodes in sequence.Meanwhile, the measurement voltage wave forms clearly showed the contraction location of stomach after the model rotating for three cycles in a row, and the phase relationship between adjacent measurement channels was also measured.The sixty seconds data acquired by the experiment device proved that voltage wave form of three measurement channels corresponded to the phase relationship of movement status of the gastric body model.Conclusions Cutaneous multichannel wave forms prove a cyclical movement of stomach, and phase difference among the multichannel signals relating to speed of peristaltic wave, position of the measuring electrodes and channel spacing, etc.This study provides simulation and experimental basis for explanation of quantitative study of conduction properties in space and phase relationship between the results of surface multichannel impedance measurements and the contractions, peristalsis of stomach.

Objective To verify the effectiveness of electrical impedance tomography (EIT) with multi-layer electrodes in gastric emptying measurement by simulation experiments using EIT with three-layer electrodes.Methods Firstly,EIT system with three-layer electrodes and gastric emptying measurement simulation equipment was designed and constructed to simulate gastric emptying process and obtain EIT reconstruction images.Secondly,the region where the electrical characteristic of gastric changes was selected as region of interest.Finally,the relative impedance change rate in region of interest for every image obtained from all three layers was consecutively recorded,then the gastric emptying curve was formed and gastric emptying time was calculated.Results There are obvious differences among the sharp of impedance change curves of interested region for three layers,and the gastric emptying time and process of each layer is also different from one another.It is suggested that the passing path and emptying manner of food in gastric emptying process reflected by EIT images varied from layer to layer.Therefore,the necessity and feasibility of using EIT with three-layer electrodes in gastric emptying measurement study is verified.Conclusions EIT with three-layer electrodes can provide more abundant information of gastric motility function associated with gastric emptying pathology and physiology state.It is likely to be a noninvasive,convenient and effective imaging method for the detection and evaluation research on gastric emptying and gastric motility.

Objective: To study the possibility of liposomes to ta rget hepatocytes af ter being linked with asialofetuin(AF). Methods: The biodistribu tions in differen t cells in liver as well as in blood, in various organs such as heart, spleen, l ung and kidney of mice, of traditional sterically stabilized liposomes(SSL) , AF-linked normal liposomes(AF-NL) and AF-linked sterically stabilized lipos ome s(AF-SSL) were studied by radioisotopic labeling. Results: The half-live s of SSL, AF-NL and AF-SSL were 14.44, 4.73 and 11.49 h， respectively. The di strib ution of liposomes in liver was AF-NL>AF-SSL>SSL. There was significant differenc e among these three formulations. In hepatocytes and non-hepatocytes, the conce ntr ations of the liposomes were both in line with the sequence AF-NL>AF-SSL>SSL( P <0.05). However, the ra tios of the concentrations in hepatocytes to that of non-hepatocytes were AF-N L≈AF -SSLSSL( P <0.05). Conclusion: After being labeled with asi alofetuin, liposomes can target hepatocytes very we ll， whether in long-circulation or not.

According to the multi-information characteristic of pulse tracings in traditional Chinese medicine(TCM) and the dynamic analysis and identification technique of sonogram,the multi-information detection system of pulse examination was constructed by combining B-type ultrasound and flexible transducer.It made information integration of supersonic dynamic image,pressure pulse wave,photoelectric capacity pulse wave and electrocardiogram,and though the aggregate analysis of computer information processing technique,established the pulse tracings signature analysis method,formed optimized solving scheme for describing the four attributes("location,velocity,shape and potential") of pulse examination in TCM.From the multi-information data of healthy people's pulse tracings collected by this system,it can be infer that the new method of objectification of pulse examination referred in this article is feasible,and have gain the prospective effect.It provides a new method and characteristic data for the clinical study of objectification of pulse examination and teaching of TCM.

Objective:To evaluate early corneal biomechanical change, safety and effectiveness after small-incision lenticule extraction combined with ultraviolet A corneal collagen cross-linking (SMILE-CXL) for myopic eyes and compare with SMILE.Methods:A non-randomized controlled clinical study was performed.Forty-four myopic eyes of 25 patients were included in Hankou Aier Eye Hospital from December 2017 to July 2018.SMILE-CXL or SMILE was carried out for 22 eyes of 12 patients or 22 eyes of 13 patients, respectively, based on the normal posterior surface manifestation of Belin by Pentacam tomography or not.The posterior surface manifestation of Belin was normal in the SMILE group, and the posterior surface of Belin was yellow or red with Corvis biomechanical index and tomographic biomechanical index<0.3 (except keratoconus) in the SMILE-CXL group.The refractive diopter of the eyes was detected before and 6 months after surgery, including spherical diopter, cylindrical diopter and spherical equivalent (SE) with a comprehensive refractometer.The corneal biomechanical parameters of the eyes were detected before and 6 months after surgery with a Scheimpflug-based dynamic tonometry (Corvis ST). The safety index, a ratio of postoperative mean best corrected visual acuity (BCVA) to preoperative mean BCVA, and efficacy index, a ratio of postoperative uncorrected visual acuity (UCVA) to preoperative BCVA, were compared between SMILE-CXL group and SMILE group.BCVA and UCVA were examined using standard chart and converted to logarithm of the minimal angle of resolution (LogMAR) units.This protocol complied with the Declaration of Helsinki and was approved by an Ethics Committee of Hankou Aier Eye Hospital (No.WHS2017052701). Written informed consent was obtained from each patient prior to entering into the cohort.Results:The postoperative UCVA of the eyes in both groups was more than 1.0.There were no significant differences in safety index, efficacy index and SE change between the SMILE-CXL group and SMILE group (all at P≥0.05). At 6 months after surgery, the values of second applanation time (A2T), time from the start until the highest concavity (HC-Time) and DA ratio 2 mm were significantly increased in comparison with before operation in both SMILE-CXL group and SMILE group (all at P<0.05). The changes of A2T, HC-Time and DA ratio 2 mm in the SMILE-CXL group were significantly lowered than those in the SMILE group at the sixth month after surgery ( P=0.001, 0.001, 0.036). The deformation amplitude, maximum corneal velocity during the first applanation (Vin), distance between both non-deformed peaks and integrated radius during the maximum depression were significantly increased, and the central curvature radius at highest concavity, cord length of first applanation, cord length of second applanation, Ambrósio's relational thickness horizontal, stiffness parameter applanation 1 and biomechanical intraocular pressure during the maximum depression were significantly lower at the sixth month after surgery than those before surgery (all at P<0.05). There were no significant differences in the parameters mentioned above between the two groups (all at P<0.05). Conclusions:Compared with SMILE alone, SMILE-CXL shows a comparable safety and efficacy, and better corneal biomechanical properties.

Objective:To investigate the impact of obstructive sleep apnea(OSA)on cardiac structure and function in elderly patients with type 2 diabetes mellitus(T2DM).Methods:This was a case-control study.Elderly patients with T2DM aged 65 years and above at the Department of Geriatrics of Tianjin Medical University General Hospital were consecutively enrolled in this study, and eventually 61 patients with complete general information were included.All patients were examined with polysomnography(PSG). They were divided into the T2DM group and the T2DM+ OSA group based on whether there was concurrent OSA.Differences in cardiac structure and function were compared between the two groups and between patients with mild OSA and those with moderate-severe OSA.The correlation of OSA with cardiac structure and function in T2DM patients was analyzed by using Pearson correlation and multiple linear regression analysis.Results:The left ventricular ejection fraction(LVEF)was lower in the T2DM+ OSA group than in the T2DM group(52.38±4.70 % vs.56.34±5.92%, t=2.892, P=0.005). The anteroposterior diameter of the right ventricle, inter-ventricular septum thickness and left ventricular posterior wall thickness increased in the T2DM+ OSA group compared with the T2DM group(21.50±1.49 mm vs.20.55±1.05 mm, 10.21±0.88 mm vs.9.52±1.04 mm, 10.42±0.83 mm vs.9.83±0.83 mm, t=-2.670, -2.770 and -2.716, P=0.010, 0.007 and 0.009). LVEF was lower in patients with moderate-severe OSA than in those with mild OSA group(50.58±3.55% vs.55.83±4.83%, t=3.813, P=0.001). The anteroposterior diameter of the right ventricle, inter-ventricular septum thickness and left ventricular posterior wall thickness were greater in patients with moderate-severe OSA than in those with mild OSA(21.86±1.39 mm vs.20.79±1.46 mm, 10.48±0.82 mm vs.9.69±0.75 mm, 10.68±0.80 mm vs.9.92±0.64 mm, t=-2.231, -2.871 and -2.943, P=0.032, 0.007 and 0.006). Pearson correlation analysis showed that the Apnea Hypopnea Index(AHI)was correlated with LVEF, the anteroposterior diameter of the right ventricle, inter-ventricular septum thickness and left ventricular posterior wall thickness( r=-0.425, 0.340, 0.458 and 0.473, P=0.001, 0.007, <0.001 and <0.001). After adjusting for age, body mass index, systolic blood pressure and triglycerides, multiple linear regression analysis showed that AHI was also correlated with LVEF, the anteroposterior diameter of the right ventricle, inter-ventricular septum thickness and left ventricular posterior wall thickness( β=-0.385, 0.520, 0.604 and 0.388, P=0.036, 0.011, 0.001 and 0.039). Conclusions:OSA aggravates cardiac remodeling and systolic insufficiency in T2DM patients and may be related to the severity of intermittent hypoxia.

Three dimensional electrical impedance tomography (3D-EIT) became an important branch of EIT recently. It is important to research imaging and image quality evaluation methods for single targets of different positions and multi-targets in 3D field. Using finite element subdivision method, 3D-EIT field was dispersed into cube unit in the present study for models with single target located in the center of field, middle of field, and near to the edge, respectively. For models with two targets and four targets near to the field edge, Tikhonov-Noser algorithm was adopted in image reconstruction. Imaging error function ER and structure similarity degree function SSIM were introduced to evaluate the reconstructed images. For the models with signal target, with the movement of the target from the center to the edge of the field, the value of ER increased and SSIM decreased, and reconstruction quality decreased. For the models with multi-targets near to the field edge, ER and SSIM increased and decreased respectively with the increase of target number, mage quality also decreased. Tikhonov-Noser algorithm is an effective 3D-EIT algorithm. ER and SSIM are adaptive for the characteristic of 3D-EIT images, and it can quantitatively evaluate the 3D-EIT imaging effect from the two perspective of imaging error and structure quality.
Algorithms ; Electric Impedance ; Image Processing, Computer-Assisted ; Imaging, Three-Dimensional ; Tomography

Objective Practical electrical impedance tomography (EIT) system with certain measurement resolution (MR) and signal-to-noise ratio (SNR) differs a lot from ideal simulation conditions in EIT methodology research. The aim of this paper was to study the impact of practical system with different MR and SNR on EIT. Methods Based on the ideal simulation boundary voltages of adjacent excitation and adjacent measurement pattern, practical systems whose MR were 0.1 mV and 0.01 mV, SNR ranged from 40-80 dB and no noises were simulated, simulation study for three imaging models A, B and C with different positions in the to-be imaged field under practical system conditions above was carried out using the combined Tikhonov-NOSER regularization algorithm, and error of reconstruction (ER) function and structure similarity (SSIM) function were adopted for quantitative evaluation of image effect. Results There are differences between images obtained under different MR and SNR for different image models. In order to obtain images for three models, SNR of system should be at least 40-50 dB when MR was 0.01 mV. For the goal to obtain high quality images of A, B and C, SNR should be 80, 70 and 60 dB respectively. When MR was 0.1 mV, SNR for obtaining images of A, B, C were 60, 50 and 40 dB. Moreover, the improvement of images with increasing SNR under MR of 0.1 mV was not as obvious as that of MR at 0.01 mV. Conclusions Blind pursuit of single high SNR is of no help to improve system performance and image reconstruction effect except increasing the difficulties in hardware design. The extremity SNR is 50-60 dB for system with MR of 0.01 mV and 60-70 dB for system with MR of 0.1 mV.