OBJECTIVETo establish the cervicothoracic spine finite element model with three-dimensional finite element method, verify the effectiveness of this model and explore the stress distribution.

METHODSDICOM image data of one normal healthy young male volunteer were obtained by spiral CT scan and processed with Mimics software. Datas were imported to ANSYS software to become a 3D entity. Disc structure and the main ligament were added. Disc structure was added using the shell-nuclear unit, representing the annulus fibrosus and nucleus pulposus. Ligament structure was established with 2-node cable element, the beginning and ending points of the ligament and the cross-sectional area were determined in accordance with references. C(6,7) and C7T1 facet joints were definded as the nonliner contact joints with friction coefficient. The lower surface of TI in all the directions was completely fixed in this model. In the model 2.0 Nm pure torque were imposed on C6, and the extension, flexion, axial rotation and lateral bending experiment were conducted. The experimental results were compared with the in vitro biomechanical tests.

RESULTSThe cervicothoracic spine finite element model included 169,317 nodes and 106,242 units, and consistent with the in vitro biomechanical tests. The three-dimensional finite element model was in good running under external force.

CONCLUSIONIt is a convenient and precise method for physicians to establish the finite element model of the cervicothoracic junction. This method facilitates the computer study on the biomechanical behavior of the local structures of the model under various pressure conditions.

Cervical Vertebrae ; anatomy & histology ; physiology ; Computer Graphics ; Finite Element Analysis ; Humans ; Male ; Models, Anatomic ; Software ; Stress, Mechanical ; Thorax ; anatomy & histology ; physiology

OBJECTIVETo establish the intrauterine growth curves of neonates in Shenzhen, China and to investigate the intrauterine growth of neonates in Shenzhen.

METHODSCross-sectional cluster sampling was performed for an on-the-spot investigation of 16 887 neonates (9 418 males and 7 469 females) with a gestational age of 27-42 weeks who were born in two hospitals in Shenzhen from April 2013 to September 2015. The Lambda Mu Sigma (LMS) method was used for the curve fitting of body weight, body length, head circumference, chest circumference, and crown-rump length.

RESULTSThe 3rd-97th percentile intrauterine growth curves for body weight, body length, head circumference, chest circumference, and crown-rump length were plotted for the neonates with a gestational age of 27-42 weeks who were divided into three groups (male, female, and mixed). The male neonates had significantly higher curves for the five indices than the female counterparts. The pattern and changing trend of body weight curves of these neonates were basically consistent with those in China Neonatal Network.

CONCLUSIONSThe percentile intrauterine growth curves for body weight, body length, head circumference, chest circumference, and crown-rump length in neonates with a gestational age of 27-42 weeks in Shenzhen which has been established can provide a reference for clinical practice in the department of neonatology.

Body Height ; Body Weight ; Cross-Sectional Studies ; Crown-Rump Length ; Female ; Fetal Development ; physiology ; Gestational Age ; Head ; anatomy & histology ; Humans ; Infant, Newborn ; Male ; Thorax ; anatomy & histology

OBJECTIVETo investigate the feasibility of clinical application of the thoracodorsal artery musculocutaneous perforator flap (TAMPF).

METHODS(1) The morphosis and blood supply of TAP flap on 15 formalized adult cadavers(30 sides) were examined by microsurgery anatomy. (2) An imitative operation of the TAMP flap and latissimus dorsi flap on 1 formalized adult cadavers (2 sides) was conducted.

RESULTS(1) A total of 102 musculocutaneous perforators larger than 0.5 mm were found in 16 specimens(32 sides). 56 perforators (55%) were originated from the medial branch and 46 (45%) originated from the lateral branch. The biggest perforator is (0.82 +/- 0.11) mm (0.68 - 1.08 mm). There was an average of 1.9 perforators (range, 1 - 3 perforators) of the medial branch and an average of 1.8 perforators (range, 1 - 3 perforators) of the lateral branch. Additionally, there were 24 perforators samller than 0.5 mm, and 76 perforators originated from intercostal artery and lumbar artery. (2) Musculocutaneous perforators over 0.5 mm were found only in proximity of the medial and lateral branches within a distance of 8.5 cm (6.4 cm - 9.2 cm) distal to the neurovascular hilus.

CONCLUSIONSWith the characteristics of constant position, large caliber, long pedicle, the thoracodorsal artery musculocutaneous perforator was suitable to be musclocutaneous perforator flaps and "fan-shaped" flaps.

Adult ; Arteries ; anatomy & histology ; Back ; blood supply ; Female ; Humans ; Male ; Surgical Flaps ; blood supply ; Thorax ; blood supply

In order to enhance the position accuracy of ablation catheter in heart electrophysiology operation, signals of respiration and heartbeat must be removed for subsequent data processing. Based on locating principle of electrical field with low frequency, synchronous detector with MC1496 has been developed in this study. In the present research, several methods are utilized to optimize the circuit performance, such as coupling and stopping direct current, low-pass filtering, as well as limiting ripple voltage etc. Through simulation results, it showed that the demodulation performance of the circuit was fine. Through simulation platform of thorax electric field and animal experiment, the circuit feasibility were further proved good for extracting signals of respiration and heartbeat.
Atrial Fibrillation ; surgery ; Catheter Ablation ; methods ; Computer Simulation ; Electromagnetic Fields ; Heart ; anatomy & histology ; physiology ; Humans ; Models, Biological ; Signal Processing, Computer-Assisted ; Thorax

Cardiothoracic ratio (CTR), the ratio of cardiac diameter (CD) to thoracic diameter (TD), is a useful screening method to detect cardiomegaly, but is reliable only on posteroanterior chest radiography (chest PA). We performed this cross-sectional 3-phase study to establish reliable CTR from anteroposterior chest radiography (chest AP). First, CDChest PA/CDChest AP ratios were determined at different radiation distances by manipulating chest computed tomography to simulate chest PA and AP. CDChest PA was inferred from multiplying CDChest AP by this ratio. Incorporating this CD and substituting the most recent TDChest PA, we calculated the 'corrected' CTR and compared it with the conventional one in patients who took both the chest radiographies. Finally, its validity was investigated among the critically ill patients who performed portable chest AP. CDChest PA/CDChest AP ratio was {0.00099 x (radiation distance [cm])} + 0.79 (n = 61, r = 1.00, P < 0.001). The corrected CTR was highly correlated with the conventional one (n = 34, difference: 0.00016 +/- 0.029; r = 0.92, P < 0.001). It was higher in congestive than non-congestive patients (0.53 +/- 0.085; n = 38 vs 0.49 +/- 0.061; n = 46, P = 0.006). Its sensitivity and specificity was 61% and 54%. In summary, reliable CTR can be calculated from chest AP with an available previous chest PA. This might help physicians detect congestive cardiomegaly for patients undergoing portable chest AP.
Aged ; Aged, 80 and over ; Cardiomegaly/*radiography ; Cross-Sectional Studies ; Dyspnea ; Female ; Heart/*radiography ; Humans ; Male ; Middle Aged ; Point-of-Care Systems ; Radiography, Thoracic/*methods ; Thorax/anatomy & histology/physiology ; Tomography, X-Ray Computed/methods

OBJECTIVEFor prevention of obesity in Chinese population, it is necessary to define the optimal range of healthy weight and the appropriate cut-off points of BMI and waist circumference for Chinese adults. The Working Group on Obesity in China under the support of International Life Sciences Institute Focal point in China organized a meta-analysis on the relation between BMI, waist circumference and risk factors of related chronic diseases (e.g., high diabetes, diabetes mellitus, and lipoprotein disorders).

METHODS13 population studies in all met the criteria for enrollment, with data of 239,972 adults (20-70 year) surveyed in the 1990s. Data on waist circumference was available for 111,411 persons and data on serum lipids and glucose were available for more than 80,000. The study populations located in 21 provinces, municipalities and autonomous regions in mainland China as well as in Taiwan. Each enrolled study provided data according to a common protocol and uniform format. The Center for data management in Department of Epidemiology, Fu Wai Hospital was responsible for statistical analysis.

RESULTS AND CONCLUSIONThe prevalence of hypertension, diabetes, dyslipidemia and clustering of risk factors all increased with increasing levels of BMI or waist circumference. BMI at 24 with best sensitivity and specificity for identification of the risk factors, was recommended as the cut-off point for overweight, BMI at 28 which may identify the risk factors with specificity around 90% was recommended as the cut-off point for obesity. Waist circumference beyond 85 cm for men and beyond 80 cm for women were recommended as the cut-off points for central obesity. Analysis of population attributable risk percent illustrated that reducing BMI to normal range (< 24) could prevent 45%-50% clustering of risk factors. Treatment of obese persons (BMI > or = 28) with drugs could prevent 15%-17% clustering of risk factors. The waist circumference controlled under 85 cm for men and under 80 cm for women, could prevent 47%-58% clustering of risk factors. According to these, a classification of overweight and obesity for Chinese adults is recommended.

Adult ; Aged ; Body Mass Index ; Body Weight ; China ; Diabetes Mellitus ; epidemiology ; ethnology ; Female ; Health Surveys ; Humans ; Hypertension ; epidemiology ; ethnology ; Male ; Middle Aged ; Obesity ; classification ; complications ; ethnology ; Reference Values ; Risk Factors ; Sex Factors ; Thorax ; anatomy & histology

OBJECTIVETo assess the state of the art of fetal magnetic resonance imaging (MRI) in China.

DATA SOURCESBoth Chinese and English language literatures were searched in the databases of PUBMED (1998-2005) and CNKI (1998-2005), 41 published articles about fetal MRI were selected.

RESULTSFetal MRI can serve as an adjunct tool for ultrasonography because of its excellent soft tissue contrast, high spatial resolution, multiplanar capabilities, large field of view and simultaneous visualization of fetal and maternal structures. Since the development of ultrafast MRI sequences provides faster scan time and avoids motion artifacts, it is widely applied in detecting normal or abnormal fetal development, including the central nervous system, thoracic region, abdomen and others. In China, experience in fetal MRI has been scanty, but the technique will be extensively used in the near future because of its multi-faceted advantages.

CONCLUSIONSCompared with ultrasonography, MRI as a complementary imaging for fetal screening is prospective in China or other parts of the world because of its multiple superiorities.

Abdomen ; abnormalities ; embryology ; Cell Movement ; Central Nervous System ; abnormalities ; embryology ; Congenital Abnormalities ; diagnosis ; Female ; Fetus ; anatomy & histology ; Humans ; Magnetic Resonance Imaging ; methods ; Myelin Sheath ; physiology ; Pregnancy ; Thorax ; abnormalities ; embryology