超声地形障碍检出系统换能器的研制

介绍适用于超声地形障碍检出传感系统，向空气辐射的弯曲振动型超声换能器的研制．该换能器结构简单，制作方便。

Low complexity iterative differential decoding algorithm for multiband UWB communication systems

Due to not requiring channel state information （CSI） at both the transmitter and the receiver, noncoherent ultra-wideband （UWB） incurs a performance penalty of approximately 3 dB in the required signal to noise ratio （SNR） compared to the coherent case. To overcome the gap, an effective differential encoding and decoding scheme for multiband UWB systems is proposed. The proposed scheme employs the parallel concatenation of two recursive differential unitary space-frequency encoders at the transmitter. At the receiver, two component decoders iteratively decode information bits by interchanging soft metric values between each other. To reduce the computation complexity, a decoding algorithm which only uses transition probability to calculate the log likelihood ratios （LLRs） for the decoded bits is given. Simulation results show that the proposed scheme can dramatically outperform the conventional differential and even coherent detection at high SNR with a few iterations.

Role of videocapsule endoscopy for gastrointestinal bleeding

Obscure gastrointestinal bleeding (OGIB) is defi ned as bleeding of an unknown origin that persists or recurs after negative initial upper and lower endoscopies. Several techniques, such as endoscopy, arteriography, scintigraphy and barium radiology are helpful for recognizing the bleeding source; nevertheless, in about 5%-10% of cases the bleeding lesion cannot be determined. The development of videocapsule endoscopy (VCE) has permitted a direct visualization of the small intestine mucosa. We will analyze those techniques in more detail. The diagnostic yield of CE for OGIB varies from 38% to 93%, being in the higher range in those cases with obscure-overt bleeding.

Capsule endoscopy in neoplastic diseases

Until recently, diagnosis and management of small-bowel tumors were delayed by the diffi culty of access to the small bowel and the poor diagnostic capabilities of the available diagnostic techniques. An array of new methods has recently been developed, increasing the possibility of detecting these tumors at an earlier stage. Capsule endoscopy (CE) appears to be an ideal tool to recognize the presence of neoplastic lesions along this organ, since it is non-invasive and enables the entire small bowel to be visualized. High- quality images of the small-bowel mucosa may be captured and small and ? at lesions recognized, without exposure to radiation. Recent studies on a large population of patients undergoing CE have reported small-bowel tumor frequency only slightly above that reported in previous surgical series (range, 1.6%-2.4%) and have also confirmed that the main clinical indication to CE in patients with small-bowel tumors is obscure gastrointestinal (GI) bleeding. The majority of tumors identified by CE are malignant; many were unsuspected and not found by other methods. However, it remains difficult to identify pathology and tumor type based on the lesion’s endoscopic appearance. Despite its limitations, CE provides crucial information leading in most cases to changes in subsequent patient management. Whether the use of CE in combination with other new diagnostic (MRI or multidetector CT enterography) and therapeutic (Push- and-pull enteroscopy) techniques will lead to earlier diagnosis and treatment of these neoplasms, ultimately resulting in a survival advantage and in cost savings,remains to be determined through carefully-designed studies.

Method of spillover identification in urban street networks using loop detector outputs

Quick and reliable identification of the traffic state is of critical importance to traffic control systems, especially when spillovers appear. Firstly, a calculation method for the occupancy per cycle under different traffic conditions were presented, based on the relationship between the three basic traffic flow parameters, speed, traffic flow and density. Secondly, the times at which the stopping and starting waves approach a loop detector were confirmed using the traffic wave models modified by a kinematic equation. Then, the threshold of occupancy, which characterizes the appearance of spillovers, was determined by the premise that the stopping and starting waves had the same speed. At last, the accuracy and usability of the new method were verified by VISSIM simulation, using the ratio of misjudgment as the evaluation index. The results show that the ratio of misjudgment of the new method is about 11.36% compared to 17.65% of the previous method.

Bronchoscopic biopsy for diagnosis of lung cancer in the absence of visible endobronchial abnormalities

Objective Bronchoscopy has been extensively used in the diagnosis of respiratory diseases, and par- ticularly, malignant diseases. However, endoscopists do not normally perform bronchoscopic biopsy in Case lesions are undetected via bronchoscopy. The aim of this study was to evaluate whether performing bron- choscopic biopsy could be established in the diagnosis of lung cancer in case of endobronchial abnormali- ties undetectable to the naked eye. Methods We retrospectively analyzed 109 cases between January 2008 and December 2012. The in- clusion criteria were confirmed lung cancer diagnosis, transbronchial biopsy performed in the absence of visible endobronchial manifestations, brushing, and bronchoalveolar lavage （BAL） according to the images obtained from high-resolution computed tomography （HRCT）. Data regarding age, sex, pathology, tumor stage; the method of diagnosis; location of primary lesion （central, peripheral, or intermediate）; tumor size, mediastinal lymph node metastasis, and the serum carcinoembryonic antigen （CEA） value were collected. The Pearson chi-square test or Fisher＇s exact and McNemar tests were used in the univadate analysis. Results Among the 109 patients, the diagnosis of 37 （33.9%） patients was confirmed through bronchos- copy. Brushing and BAL had higher positive detection rates than biopsy （P = 0.004）. There were no differ- ences in the positive detection rates between the sex, pathology, lesion location, tumor size, lymph node metastasis, and the serum CEA value （P〈 0.05 for all groups）. Conclusion Despite the normal appearance of the endobronchial manifestations, lesions undetectable by bronchoscopy could be indicated. Therefore, we suggest performing bronchoscopic biopsy and that brushing and BAL might increase the positive detection rate of bronchoscepic examination.

Gene mutations and clinical phenotypes in Chinese children with Blau syndrome

The mutations of CARD15 gene and clinical features of Chinese patients with Blau syndrome were analyzed. We identified10 missense mutations, out of which five were new: R334 L, E383 D, R471 C, C495 R and D512 F. The rest of them, R334 W,R334Q, G481 D, M513 T and R587 C, have been reported previously. Among all the mutations, R334 W, R334 Q and C495 R had the highest frequency. Blau syndrome was found at early age after birth. It began with lepidic rash and symmetric polyarthritis and was phenotypically characterized by typical rash, arthritis, iridocyclitis and arteritis. Cardiac involvement was also found in Blau syndrome. In addition to nerve deafness, renal involvement, osteochondroma and central nervous system involvement were also found in our patients. Therefore, Chinese children with Blau syndrome have unique gene mutations and complicated clinical phenotypes. Pathologic examination and CARD15 mutation testing should be considered for diagnosis as early as possible for suspected patients.