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Purpose Design, fabricate and evaluate all-solid-state wearable sensor systems that can monitor ion concentrations in human sweat to provide real time health analysis and disease diagnosis capabilities. Design/methodology/approach A human health monitoring system includes disposable customized flexible electrode array and a compact signal transmission-processing electronic unit. Findings Patterned rGO (reduced-graphene oxide) layers can replace traditional metal electrodes for the fabrication of free-standing all solid film sensors to provide improved flexibility, sensitivity, selectivity, and stability in ion concentration monitoring. Electrochemical measurements show the open circuit potential of current selective electrodes exhibit near Nernst responses versus Na+ and K+ ion concentration in sweat. These signals show great stability during a typical measurement period of 3 weeks. Sensor performances evaluated through real time measurements on human subjects show strong correlations between subject activity and sweating levels, confirming high degree of robustness, sensitivity, reliability and practicality of current sensor systems. Originality/value In improving flexibility, stability and interfacial coherency of chemical sensor arrays, rGO films have been the developed as a high-performance alternative to conventional electrode with significant cost and processing complexity reduction. rGO supported solid state electrode arrays have been found to have linear potential response versus ion concentration, suitable for electrochemical sensing applications. Current sweat sensor system has a high degree of integration, including electrode arrays, signal processing circuits, and data visualization interfaces.

Knowing the course of Alzheimer’s disease is very important to prevent the deterioration of the disease, and accurate segmentation of sensitive lesions can provide a visual basis for the diagnosis results. This study proposes an improved end-to-end dual-functional 3D convolutional neural network for segmenting bilateral hippocampi from 3D brain MRI scans and diagnosing AD progression states simultaneously. The proposed neural network is based on the V-Net and adopts an end-to-end structure. In order to relieve the excessive amount of convolutional parameters at the bottom of the V-Net, we change them to bottleneck architecture. Based on the segmentation network, we establish a classification network for diagnosing pathological states of brain. In order to balance the two tasks of hippocampi segmentation and brain pathological states diagnosis, we designed a unique loss function. This study included 132 samples, of which 100 were selected as training, and the remaining 32 were used to test the performance of our model. During training, we adopted fivefold cross-validation method. We selected the intersection over union and dice coefficient to evaluate the hippocampus segmentation performance, while the brain pathological states diagnosis performance was evaluated by accuracy, specificity, sensitivity, precision and F1 score. By using the proposed neural network, the left hippocampi segmentation Iou and dice coefficient reach 0.8240 ± 0.020 and 0.9035 ± 0.020, respectively. The right hippocampi Iou and dice coefficient reach 0.8454 ± 0.023 and 0.9162 ± 0.023, respectively. The accuracy, specificity, sensitivity, precision and F1 score of three-category classification of brain pathology are 84%, 92%, 84%, 86% and 85%, respectively. The proposed neural network has two functions of brain pathological states diagnosis and bilateral hippocampi segmentation with higher robustness and accuracy, respectively. The segmented bilateral hippocampi can be used as a reference for clinical decision making or intervention.

Endoscopic closure has become the first choice for closing iatrogenic perforations. Previously, we reported a self-developed endoscopic multifiring clip applicator (EMFCA) system. In this paper, a new EMFCA system for endoscopic closure of large perforations with a redesigned clip, the less traumatic grasper, and a highly efficient driving system was presented, and its efficacy was evaluated. The behaviors of the new clip and grasper were verified through finite element analysis (FEA). The capability of pushing transmission for the EMFCA system was identified by the proposed model and the validation experiment. Ex-vivo studies were conducted on porcine stomachs to compare the outcomes of the closures. The FEA results showed that the deformation of the clip was safe and smoother, with a maximum stress of 640.0 MPa. The less traumatic grasper could increase the grasping force and avoid trauma by exerting uniform stress along the axis. The capability of pushing transmission was enhanced by the double-nested tendon-sheath actuation system with an efficiency of 0.45–0.48. The mechanical strength, the leakage pressure, and the operating time for the closures with the new EMFCA system and the previous EMFCA system were 6.1 N ± 0.8 N, 37.1 mmHg ± 6.8 mmHg, 7.3 min ± 0.4 min and 5.1 N ± 1.0 N, 27.4 mmHg ± 6.4 mmHg, 11.4 min ±0.8 min, respectively. The new EMFCA system can realize a superior, reliable, and high-efficiency endoscopic closure of large perforations.

Structurally retrievable drug-eluting stents may have valuable clinical applications because they do not leave any foreign materials inside the patient's body. This article presents a novel design of retrievable peripheral vascular stent and the results from biomechanical analysis of its performance. Using the finite element analysis method, principal parameters of the stent were studied. Moreover, to ensure the practicability of the retrieval process, simulation, and in vitro experiments were performed. The retrieval force reached the maximum value when the whole retrievable part had been retrieved. Furthermore, the force was gradually increased during the retrieval process and remained constant after the main part had been retrieved. When the stent was being compressed, the maximum strain of the stent occurred at the connection between the stent's retrieval part and the main body part, at a value of 4%. The index of nonuniformity of the stent was too small to be counted both at the end of the compression and self-expansion processes. With the increase of moment, the bending stiffness (EI) of the stent decreased gradually. After bending moment was applied, the large strain region was mainly located in the stent's main body part rather than the retrieval part. The results of preliminary stent retrieval experiments demonstrated that the stent could be retrieved successfully. This novel retrievable stent displays promising biomechanical performance. The preliminary experiments demonstrated that the stent could be retrieved smoothly from the blood vessels.

Precompression is vital when performing gastrointestinal anastomosis with staplers. However, research on the internal changes in intestinal tissue under stapling is lacking, and the effects of precompression have not been clarified. In this study, a stapler was modified, and the multifrequency bioimpedance of porcine small intestinal tissue was measured from before clamping the tissue with the stapler until the release of the tissue after precompression without firing. The Cole Y model was fitted to the bioimpedance, and the changes in the tissue were analyzed using the model parameters: G0, extracellular fluid conductance, and Δ G, intracellular fluid conductance. The results show that the changes of G0 and Δ G could be divided into four stages: rapid decrease, slow decrease, intense resilience, and slow recovery. During slow decrease stage, there was a greater decrease of G0 and Δ G (1.02E−05 ± 1.12E−05 S and 1.73E−05 ± 2.12E−05 S in precompression time’s increase, 1.68E−05 ± 8.74E−06 S and 1.20E−05 ± 1.09E−05 S in precompression strength’s increase). On the contrary, during intense resilience stage, there was a less increase of G0 and Δ G (0.88E−05 ± 4.86E−05 S and 9.15E−05 ± 9.37E−05 S in precompression time’s increase, 2.72E−05 ± 3.53E−05 S and 1.02E−04 ± 8.54E−05 S in precompression strength’s increase). In conclusion, the effects of precompression factors on tissue have been preliminary revealed: the tissue under precompression becomes thinner and less resilient. To improve the precompression effects and reduce any excessive pressure exerted on the staples by tissue resilience, the precompression time and strength should be increased appropriately.

Quantitative assessment of mammographic asymmetry has been investigated for breast cancer risk prediction. A new asymmetry feature extraction method was proposed in this study to enhance the risk prediction accuracy of near-term breast cancer. Breast areas in each pair of bilateral mammographic images were divided into several pairs of matched local annular regions and the maximum local asymmetry features (MLAF) were extracted from these regions. Radial basis function network (RBFN) was used to merge these features for breast cancer risk prediction. The dataset included 560 negative subjects. The risk prediction performance was tested using a leave-one-case-out (LOCO) cross-validation method. Area under the receiver operating characteristic curve (AUC) was used as the risk prediction performance evaluation index. AUC = 0.898 ± 0.013 was obtained by using the MLAFs extracted from the annular regions, which was significantly higher than the AUC value of 0.505 ± 0.025 achieved by using global asymmetry features computed from the whole breast regions (p

Endoscopic closure is an essential procedure in gastrointestinal (GI) surgery, but currently it is difficult to close large defects endoscopically because of the lack of an appropriate device. Previously, we developed an endoscopic clipping device that has multifiring function and is equipped with an independent clamp. The goal of this study is to provide a new closure method with this device and 4S-modified Roeder (4SMR) slipknot. The feasibility of the closure method is examined by deploying two clips during one insertion onto the 4SMR slipknot to close a 5 cm full-thickness linear defect of an ex vivo porcine stomach from the center. Mechanical strengths of clip-knot closure and the slipknot as regards to tensioning forces are also evaluated. Specifically, the mechanical strength of the 4SMR slipknot is verified by mean peak forces to failure, while the knot is tensioning by 2.5, 5, 7.5, and 10 N force (n = 20 for each group), respectively. Experimental results indicate the clip-slipknot closure can withstand a distracting force of 6.3 ± 5.6 N. Tensioning force has a great influence on the mechanical strength of slipknot, with the mean peak force (tensioning force) being 7.1± 6.5, 16.3 ± 9.3, 18.9 ± 10.4, and 24.2 ± 12.0 N, respectively. The proposed closure method can be used for large defects. Tensioning force higher than 5 N is suitable to ensure a stronger 4SMR slipknot.

The administration of neoadjuvant chemotherapy (NAC) preceding radical cystectomy benefits overall survival for patients with muscle-invasive bladder cancer (MIBC). However, the relationship between the genetic profiling of MIBC and NAC response remains unclear. Here, a mutation panel of six cancer-associated genes (TSC1, FGFR3, TERT, TP53, PIK3CA and ERBB2) and an immunohistochemistry (IHC) panel containing eight bladder cancer (BC) biomarkers (EGFR, RRM1, PD-L1, BRCA1, TUBB3, ERCC, ERCC1, aberrantly glycosylated integrin α3β1 (AG) and CK5/6) were developed. BC samples from patients who showed a pathologic response (n = 39) and non-response (n = 13) were applied to the panel analysis. ERBB2, FGFR3 and PIK3CA exclusively altered in the responders group (19/39, 48.7%), in which FGFR3 mutations were significantly enriched in patients with a response in the cohort (14/39, 35.9%; P = 0.01). Additionally, strong expression of ERCC1 was associated with a pathologic response (P = 0.01). However, positive lymph node metastasis (P 0.01) and lymph-vascular invasion (LVI) (P = 0.03) were correlated with a non-response. Overall, the data show that FGFR3 mutations and elevated expression of ERCC1 in MIBCs are potential predictive biomarkers of the response to NAC.

Accurately detecting and removing pectoral muscle areas depicting on mediolateral oblique (MLO) view mammograms are an important step to develop a computer-aided detection scheme to assess global mammographic density or tissue patterns. This study aims to develop and test a new fully automated, accurate and robust method for segmenting pectoral muscle in MLO mammograms. The new method includes the following steps. First, a small rectangular region in the top-left corner of the MLO mammogram which may contain pectoral muscle is captured and enhanced by the fractional differential method. Next, an improved iterative threshold method is applied to segment a rough binary boundary of the pectoral muscle in the small region. Then, a rough contour is fitted with the least squares method on the basis of points of the rough boundary. Last, the fitting contour is subjected to local active contour evolution to obtain the final pectoral muscle segmentation line. The method has been tested on 720 MLO mammograms. The segmentation results generated using the new scheme were evaluated by two expert mammographic radiologists using a 5-scale rating system. More than 65% were rated above scale 3. When assessing the segmentation results generated using Hough transform, morphologic thresholding methods and Unet-based model, less than 20%, 35% and 47% of segmentation results were rated above scale 3 by two radiologists, respectively. Quantitative data analysis results show that the Dice coefficient of 0.986 ± 0.005 is obtained. In addition, the mean rate of errors and Hausdorff distance between the contours detected by automated and manual segmentation are FP = 1.71 ± 3.82%, FN = 5.20 ± 3.94% and 2.75 ± 1.39 mm separately. The proposed method can be used to segment the pectoral muscle in MLO mammograms with higher accuracy and robustness.

Late stent thrombosis (LST) following drug-eluting stent (DES) implantation in patients with coronary artery disease (CAD) is often associated with delayed vascular healing, resulting from vascular inflammation and hypersensitivity to durable polymers and drugs. Therefore, DES design, materials, and coatings have been technologically revolutionized. Herein, we designed a novel abluminal groove-filled biodegradable polymer sirolimus-eluting stent (AGF-BP-SES), with a sirolimus content of only about one-third of traditional DES. The mechanical performances of AGF-BP-SES during compression and expansion were investigated. The pharmacokinetic (PK) profile of sirolimus was studied in the swine model. The in vivo efficacy of AGF-BP-SES was compared with that of Xience PRIME® stent. The results showed that AGF-BP-SES exhibited mechanical properties similar to traditional DES, including the rebound ratio of radial contraction/direction, rebound ratio of axial contraction/direction, and inhomogeneity of compression/expansion. Despite utilizing a reduced dose of sirolimus, AGF-BP-SES delivered sirolimus to the coronary artery in a controlled and efficient manner. The stent maintained a safe and effective local drug concentration without local or systemic risks. In the swine model, histopathological indicators predicted safety and biocompatibility of AGF-BP-SES. In conclusion, AGF-BP-SES maintained similar mechanical properties as other stents while reducing the drug-loading capacity, and showed a favorable safety and efficacy profile of the targeted DES.

An accurate detection of the effective values of electric voltage and current from high frequency power generators is a precondition for the development of smart electrotomes. In this light, an energy detection system based on personal computer (PC) is developed hereby. It senses voltage and current in isolation from generators with transformers, and then the measured values are amplified, filtered, transformed into single-ended signals and converted to RMS. The detected signals are transformed into digital signals through Data Acquisition Card (DAQ) and the data are processed with quadratic fit in Labview. Finally, the controller completes constant power output. The experiment results indicate that the energy detection system can measure the output parameters precisely and the controller can achieve constant power control.

Existing endoclip closure devices have difficulty in closing large colonic perforation. We developed a novel endoscopic multi-firing-clip applicator (EMFCA) system to address these limitations, and report on its initial evaluation.The functionality and efficacy of the prototype EMFCA equipped with re-openable clamp and preloaded with four clips were assessed using standardized 1.5 cm incisions created in ex-vivo porcine colonic segments. Endoscopic closure of the lacerations with two, three and four clips (n = five for each group) was followed by measurement of the leakage pressure of the three groups. Finite element analysis (FEA) was performed to validate the clip behavior and reliability during deployment.All 15 perforations were sealed without leakage until fully distended. The leakage pressures of colonic lacerations sealed with two, three, and four clips were 26.1 ± 2.8 mmHg, 37.3 ± 7.3 mmHg and 42.3 ± 7.4 mmHg, respectively. The mean operation time to deploy one clip was 25.4 ± 5.2 seconds. On FEA, the deformation of the shape of the clip matched that of the intended design, with each clip sustaining a maximum stress of 648.5 MPa without any material failure during deployment.These initial results confirm the efficacy of the EMFCA prototype system for endoscopic closure of colonic perforations.

The aim of this study was to validate a modified method of using a laparoscopic compression anastomosis clip (LapCAC) for gastrointestinal anastomosis in an animal experiment and two clinical cases. Anastomotic surgery of the upper digestive tract was performed on dogs using the conventional and modified methods for LapCAC. The animals were sacrificed postoperatively at different time points to obtain sections from the anastomotic site for pathologic study. Anastomotic outcomes of the two methods were also verified in two clinical cases. The animal experiments and the two clinical cases showed that no anastomotic leakage occurred with the modified method, and that the new method was simple, convenient and reliable as compared with the conventional method. The mean time of placing the anastomosis clip was shorter, and the mean numbers of operation attempts, secondary actions and sutures in the operating holes were reduced. The serosa at the anastomosis healed completely, the muscular layer and submucosal fibers proliferated well, and the anastomosis was covered with mucosa within two weeks after the operation. LapCAC offered a better surgical outcome when it was used according to the modified method, where anastomoses formed smoothly and completely within two weeks after the operation.

An infrared endoscopic system has been developed to investigate thermal spread and collateral damage during energized laparoscopic surgery, the system consists of an infrared endoscope and a thermal camera (3-5 μm) with combined thermal sensitivity of 0.05°C. The system performance was evaluated in live animals with electrosurgical devices to monitor intraoperative thermal changes. During activation periods, the peak temperature of the jaws averaged 100.5 ± 5.8 ℃ with a thermal spread of 3.0 ± 0.9 mm. For laparoscopic dissections of the esophagus-gastric junction with the 10 mm Atlas, the maximum jaw temperature was 105.2 ± 2.1 ℃ with a bigger thermal spread of 11.5 ± 7.2 mm). The study has confirmed that infrared endoscopy is a very useful tool adjunct to conventional endoscopy, which may improve the safety of energized laparoscopic dissections.

Glossy balloons were used to enhance deep vein thrombolysis. However, thrombi tend to yield in the balloon dilatation due to their smooth surface. It may be preferable to enhance thrombolysis by using balloons with a rough surface, instead of balloons with a smooth surface.Four rabbits were used for the experiment and 60 blood clot samples were obtained, and the samples were randomly separated into one control group and four balloon-solubilised groups. Urokinase solution (5000 U/ml) was used as the thrombolytic drug. The balloon-solubilised groups were enhanced respectively by 1 atm and 2 atm pressurised glossy balloons, and 1 atm and 2 atm pressurised corn-shaped balloons. Thrombolysis rates and residual rates for different granularities of blood clots were calculated for comparasion.Thrombolysis rates of the groups using corn-shaped balloons were higher than those of the groups using glossy balloons (p = 0.003 and p = 0.002). Residual rates of Φ ≥ 3.7 mm blood clots for the groups using corn-shaped balloons were lower than those for the groups using glossy balloons (p0.001 and p0.001).Balloons could be used to enhance thrombolysis; under the same balloon dilatation pressure, thrombolysis rates when using corn-shaped balloons are better than those when using glossy balloons.

Successful vascular sealing by radiofrequency (RF)-induced tissue fusion is well established. The present study reports on a novel electrode structure design together with its experimental assessment for RF thermo-fusion of porcine colonic segments.Two types of electrode were constructed and used in the present study: one with a conventional smooth surface (S) and the other with a novel reciprocating concave-convex (CC) configuration. Finite element modeling was used to study the thermal distribution profile of the CC electrode. Ex vivo porcine colonic segments were used to create end-to-end serosa-to-serosa colonic anastomoses by applying a pulse of 160 W RF power for 20 s. Different compression pressures (S1, S2, S3) and (C1, C2, C3, C4, C5), were applied, via specially designed ring carriers, to the S and CC electrodes, respectively. Assessment was based on anastomotic burst pressures and histological appearances using light microscopy of paraffin sections.In total, 22 RF-induced circular anastomoses were performed. Similar burst pressures were observed for anastomoses created by the two types of electrodes (S, CC) performed under the same compression pressure. In contrast, significant differences were observed on histological examination of tissue anastomotic site. In particular, fusion areas between gaps of the CC electrode showed normal histological appearance, while the S electrode produced a completely flat featureless appearance. Furthermore, the CC electrode produced significantly different burst pressures depending on the applied compression pressure during thermo-fusion: compression pressures C1 vs. C4 produced circular anastomotic fusions with burst pressures of 21.9 ± 9.3 vs. 44.6 ± 8.9 mmHg, (p = 0.034); but the burst pressure beyond C4, declined significantly, with C4 vs. C5, burst pressures of 44.6 ± 8.9 vs. 24.7 ± 8.0 mmHg, (p = 0.034).The CC electrode exhibits larger and faster thermal diffusion profiles resulting in normal histological appearances in the gaps between CC electrode by protecting tissue from mechanical and thermal damage.

We demonstrate a novel ultra-broad tunable bandwidth and narrow instantaneous line-width swept laser source using combined tunable filters working at 1290 nm center wavelength for application in optical coherence tomography. The combined filters consist of a fiber Fabry-Perot tunable filter (FFP-TF) and a polygon mirror with scanning grating based filter. The FFP-TF has the narrow free spectral range (FSR) but ultra-high spectral resolution (narrow instantaneous bandwidth) driven at high frequency far from resonant frequency. The polygon filter in the Littrow configuration is composed of fiber collimator, polygon mirror driven by function generator, and diffractive grating with low groove. Polygon filter coarsely tunes with wide turning range and then FFP-TF finely tunes with narrow band-pass filtering. In contrast to traditional method using single tunable filter, the trade-off between bandwidth and instantaneous line-width is alleviated. The combined filters can realize ultra wide scan range and fairly narrow instantaneous bandwidth simultaneously. Two semiconductor optical amplifiers (SOA) in the parallel manner are used as the gain medium. The wide bandwidth could be obtained by these parallel SOAs to be suitable for sufficient wide range of the polygon filter’s FSR because each SOA generates its own spectrum independently. The proposed swept laser source provides an edge-to-edge scanning range of 180 nm covering 1220 to 1400 nm with instantaneous line-width of about 0.03 nm at sweeping rate of 23.3 kHz. The swept laser source with combined filters offers broadband tunable range with narrow instantaneous line-width, which especially benefits for high resolution and deep imaging depth optical frequency domain imaging.

The design and development of the miniaturized interferometer for measurement of the refractive index or concentration of sub-microliter volume aqueous solution in microfludic chip is presented. It is manifested by a successful measurement of the refractive index of sugar-water solution, by utilizing a laser diode for light source and the small robust instrumentation for practical implementation. Theoretically, the measurement principle and the feasibility of the system are analyzed. Experimental device is constructed with a diode laser, lens, two optical plate and a complementary metal oxide semiconductor (CMOS). Through measuring the positional changes of the interference fringes, the refractive index change are retrieved. A refractive index change of 10 -4 is inferred from the measured image data. The entire system is approximately the size of half and a deck of cards and can operate on battery power for long time.

Radio-frequency (RF) tissue fusion means sealing tissue between a knife and an electrode (monoploar) or two electrodes (biopolar) delivering RF currents. Even the mechanism of adhesion is poorly understood, RF modification is correlated to thermal damage. In this paper, a multimodal monitoring system with Aluminum-doped Zinc-Oxide (AZO) thin films glass as electrode is proposed and chicken bowel is chosen as tissue to be fused, thermocouple, impedance test module, video cassette recorder and burst pressure test module can record the whole process and test the result. It was capable of acquiring temperature of electrode, impedance of tissue, while the whole process of tissue modification been visible. As tissue being fused, burst pressure can be measured. Results show the process of RF tissue fusion, and transparent conductive films are capable of being a new kind of electrode in electrosurgery.

High Intensity Focused Ultrasound (HIFU) is finding increasing application and acceptance as a non-invasive approach to the treatment of targeted malignancy. Despite the wealth of research and interest in HIFU, there are still a number of issues that need to be overcome to extend its clinical applications. These relate to the accuracy of placing the HIFU beam, the ability to visualize the target volume, and the understanding of the beam interaction with tissue. In this paper, the output characteristics of a single element HIFU transducer have been investigated with the assistance of a six-axis modified industrial robot. It is shown in the experimental results that clearly defined thermal or mechanical damage can be produced by changing the parameters of the HIFU. The nature and patterns of damage produced by pre-programmed treatment are now being investigated in tissue.

A fiber confocal backscattering FCBS spec- trometer is developed based on fiber confocal microscopy and light scattering theory. The FCBS spectrometer can provide imaging and spectral information simultaneously at the cellular scale. Normal stomach epithelial cell line GES-1 and cancerous cell line NCI-N87 are measured and their spectral results show that backscattering intensity from NCI-N87 cells is stronger than that from GES-1 cells in 500 to 800 nm, and the GES-1 cells scattering spectra show regular intensity changes, while the NCI-N87 cells do not. The experiments prove that the FCBS spectrometer is able to distinguish cancerous cells from normal stomach cells at the cellular level. The spectrometer could be fur- ther developed into a noninvasive optical technology for early cancer detection. © 2010 Society of Photo-Optical Instrumenta