An estimation of mechanical stress on alveolar walls during repetitive alveolar reopening and closure.

Alveolar overdistension and mechanical stresses generated by repetitive opening and closing of small airways and alveoli have been widely recognized as two primary mechanistic factors that may contribute to the development of ventilator-induced lung injury. A long-duration exposure of alveolar epithelial cells to even small, shear stresses could lead to the changes in cytoskeleton and the production of inflammatory mediators. In this paper, we have made an attempt to estimate in situ the magnitudes of mechanical stresses exerted on the alveolar walls during repetitive alveolar reopening by using a tape-peeling model of McEwan and Taylor (35).

A micromechanical model for estimating alveolar wall strain in mechanically ventilated edematous lungs.

To elucidate the micromechanics of pulmonary edema has been a significant medical concern, which is beneficial to better guide ventilator settings in clinical practice. In this paper, we present an adjoining two-alveoli model to quantitatively estimate strain and stress of alveolar walls in mechanically ventilated edematous lungs. The model takes into account the geometry of the alveolus, the effect of surface tension, the length-tension properties of parenchyma tissue, and the change in thickness of the alveolar wall.

Contributions of non-spherical hip joint cartilage surface to hip joint contact stress.

The natural non-spherical incongruent hip joint cartilage surface is normally assumed as spherical in shape, which has been extensively applied in orthopedic clinic, hip joint simulation studies and hip joint prosthesis design. The aim of the study was to investigate the contributions of non-spherical incongruent hip joint cartilage surface to the hip joint contact stress, and to assess the effect of simplified spherical assumption on the predicted contact stress. Based on our previous anatomic studies that the acetabular cartilage surface was demonstrated as rotational ellipsoid in shape, three finite element (FE) models involving the natural hip joint cartilage shape, the hip joint cartilage shape replaced by the rotational ellipsoid and the sphere, respectively, were developed using the computed tomography (CT) image data of healthy volunteers.

The shape of the acetabular cartilage surface and its role in hip joint contact stress.

The acetabular cartilage is normally represented as a spherical shape in orthopedic clinic and related researches. The aim of the study was to present a new mathematic representation with better fit to the acetabular cartilage surface and to investigate the role of its shape on the hip joint contact stress.

High-intensity focused ultrasound with large scale spherical phased array for the ablation of deep tumors.

Under some circumstances surgical resection is feasible in a low percentage for the treatment of deep tumors. Nevertheless, high-intensity focused ultrasound (HIFU) is beginning to offer a potential noninvasive alternative to conventional therapies for the treatment of deep tumors. In our previous study, a large scale spherical HIFU-phased array was developed to ablate deep tumors.

Computer-assisted orthopedic diagnosis and preoperative planning system based on the integrated electronic patient record.

Computer-assisted orthopedic diagnosis and preoperative planning have been recognized as efficient tools to improve the accuracy of clinic diagnosis and surgical procedure. In orthopedic clinic, such practices are heavily relied on the patient-specific medical image data.

[A study on the mechanism of inducing apoptosis of Tca8113 cells by means of ultrasound hyperthermia].

Purpose: To investigate the mechanism of apoptosis in Tca8113 cells induced by ultrasound hyperthermia by detecting changes in related index.

Methods: Tca8113 cells were treated in vitro by ultrasound hyperthermia in different heating temperatures (38 degrees C to 44 degrees C,10 minutes) and heating times (42 degrees C,10 to 60 minutes), and then the dynamic changes of early apoptosis and secondary necrosis treated by 42 degrees C for 10 minutes were assayed to detect deltapsim and Caspase-3 levels of different groups by flow cytometry (FCM). The means of each group were compared by ANOVA with SAS6.

Segmentation of LSCM Images based on Multi-channel Information Fusion.

The two channels of LSCM, the fluorescent light channel and the visible light channel, provide us with different modality images that contain special information respectively. In this paper we propose a new and integrated approach to segment images in the fluorescent light channel of LSCM, which have rather low SNR and can not provide sufficiently high intensity gradient at the boundary. Our approach, rather than relying on information of the velocity field alone, also includes statistical information of images in the visible light channel which provide subtle information of vessel structures.

Investigation of a phenylalanine-biosensor system for phenylketonuria detection.

Detection and prevention of Phenylketonuria (PKU) is becoming more and more important. However, the current methods are either imprecise or time-consuming. We propose a biosensor system based on phenylalanine ammonia-lyase (PAL) immobilized on an ammonia electrode to measure blood phenylalanine for PKU prevention.

Multi-modality medical image registration using support vector machines.

The registration of multi-modality medical images is an important tool in surgical application. We presented a method of computing different modality medical images registration of the same patient. It incorporates prior joint intensity distribution between the two imaging modalities based on registered training images.

[Experimental study on ultrasound heating affecting the sensitivity of oral carcinoma to chemotherapy drugs].

Objective: To explore the influence of chemosensitivity of Tca8113 cells by modified MTT assay after the animal model of Tca8113 were treated by the ultrasound hyperthermia.

Methods: The MTT assay of the BALB/C nu/nu mice model of Tca8113 cells treated by the ultrasound hyperthermia in vivo was performed.

Results: The chemosensitivity to the 9 kinds of drugs demonstrated no significant differences between the Tca8113 cells in the control group, the 39 degrees C-treated group and the groups treated from 41 degrees C to 44 degrees C.

SVM for density estimation and application to medical image segmentation.

A method of medical image segmentation based on support vector machine (SVM) for density estimation is presented. We used this estimator to construct a prior model of the image intensity and curvature profile of the structure from training images. When segmenting a novel image similar to the training images, the technique of narrow level set method is used.

[Development of RF ablation therapeutic instrument based on improved PID algorithm].

The development of a RF ablation therapeutic instrument based on improved PID algorithm is introduced here. It is based on the theory of radio frequency local destruction. By adopting the improved PID temperature control algorithm, the problem of the temperature control precision reduction due to tumor tissue characteristic changing by heating has been solved, thus ensuring homogeneous and smooth radio frequency heating to tumor foci.

[The development of 3D US system for treating target localization in focused ultrasound surgery].

Focused Ultrasound Surgery (FUS) is a promising minimally invasive technique in tissue ablation. Because of the high intensity at the ultrasound focus, a precise 3D-localization system is required to determine the site of the treating target in order to increase the efficiency and security of FUS. This paper represents a three dimensional ultrasound (3D US) localization system developed and its workflow.

[Development of the combined tumor therapeutic equipment].

This paper describes the development of the combined tumor therapeutic equipment based on the theory of 1 + 1 = 3 or 1 + 1 > 3 tumor combined treatment synergism. It has become a promising and valuable method dealing with cancer tumors for its good adaptability, better effectiveness and convenience. The therapeutic equipment is combined with PC and MS windows operation system, and adopts intellectual temperature control device, which realizes homogeneous and smooth heating to intracavity tumor focus and automatic processing and statistical management of all case data.

[The software design of an ultrasonic hyperthermia instrument based on an ARM embedded system].

Development of an ultrasonic hyperthermia instrument's software based on ARM32 microprocessor is here introduced. The system integrates the embedded SOC system, memory system, PWM system, A/D system, JTAG debug system, UART communication system, I/O system and GUI system (include LCD, keyboard) in one PCB board. It effectively completes the control and constance of temperature through the improved PID algorithm, and the instrument miniaturization.

Correlation dimension and the largest Lyapunov exponent characterization of RR interval.

Objective: To search for evidence of deterministic chaos and to characterise it quantitatively in RR intervals of different subjects.

Method: An improved Grassberger-Procaccia (GP) algorithm was proposed for computing the correlation dimensions (CD) of RR intervals in ten healthy young men, ten healthy old men, and ten atrial fibrillation (AF) patients. Analysis was also performed by calculating the largest Lyapunov exponents.