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In Escherichia coli, the origin of DNA replication, oriC, becomes transiently hemimethylated at the GATC sequences immediately after initiation of replication and this hemimethylated state is prolonged because of its sequestration by a fraction of outer membrane. This sequestration is dependent on a hemimethylated oriC binding protein such as SeqA. We previously isolated a clone of phage lambda gt11 called hobH, producing a LacZ fusion protein which recognizes hemimethylated oriC DNA. Very recently, Thaller et al. (FEMS Microbiol. Lett. 146 (1997) 191-198) found that the same DNA segment encodes a non-specific acid phosphatase, and named the gene aphA. We show here that the interruption of the aphA reading frame by kanamycin resistance gene insertion, abolishes acid phosphatase (NAP) activity. Interestingly, in the membrane of the null mutant, the amount of SeqA protein is about six times higher than that in the parental strain, suggesting the existence of a regulatory mechanism between SeqA and NAP expression.  相似文献   
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The key words for the future telecommunications are personalization, multi-media services and high accessibility to the network. These trends naturally lead to radio media application to access links. In this sense, this paper proposes an advanced wireless access system with a capacity supporting broadband video and data services.Concept of the system can be defined as a new radiocommunication category with advantages of both fixed and mobile systems.The system is designed to transport ATM-based signals using SHF (or EHF) bands to wireless terminals, interconnected with optical fibers at the network side. The basic system configuration is presented as well as examples of system parameters.For radio aspects the maximum service coverages of the radio base stations are calculated based on availability consideration. Preferred frequency bands for actual operation are also discussed.  相似文献   
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We performed off pump CABG (coronary artery bypass grafting) and right upper lobectomy with R2a lymph nodes dissection on the patient suffered from both lung cancer in the right S1 and stenotic lesion in the left anterior descending artery. Because the coronary lesion was long-segmented one, it was not suitable for percutaneous transluminal coronary angioplasty. To perform absolutely curative operation for the lung cancer, CABG was undergone simultaneously under off pump condition. It is generally feared that the cardiovascular surgery under CPB may have adverse effect for the patient with malignant lesion. Off pump CABG is expected to avoid such disadvantage of CPB, and thought to be suitable method for such a patient as we present above.  相似文献   
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Two cases of bronchogenic carcinoma undergone left upper lobectomy (R 3) with bronchoplasty and sleeve pulmonary arterial resection via mid-sternotomy were reported. Both cases were squamous cell carcinoma originated in the orifice of the left upper lobe. Case 1 was stage IIIB (T2N3M0) bronchogenic carcinoma, its postoperative course was uneventful and died of distant lymphatic metastasis thirty-three months after operation. Case 2 was stage II (T2N1M0) bronchogenic carcinoma and its postoperative management was laborious because of hard expectoration of the sputum but is doing well fifteen months after operation. In order to preserve adequate pulmonary function and to maintain reasonable quality of life (QOL) for the patients with impaired pulmonary function, this angioplastic procedure seems to be acceptable. It is still under discussion to perform this procedure for the patients who would be able to withstand undergoing pneumonectomy, therefore we adopt this method only for every patient for whom it is difficult to maintain desirable QOL after pneumonectomy. Namely, for the patient whose predicted one second forced expiratory volume (FEV1.0) after pneumonectomy is less than 900 ml/m2, we'll be likely to try this angioplastic procedure at first.  相似文献   
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A single-chip CMOS LSI that integrates all analog-to-digital (A/D), digital-to-analog (D/A), peripheral, and digital signal processing circuits necessary for a digital National Television System Committee (NTSC) signal decoder is described. The LSI chip accepts composite NTSC video signals in analog form, digitizes them using the on-chip A/D converter, converts them to component RGB signals, and then converts the signals to analog form by using the on-chip D/A converters. The development of circuits that maximize use of the input digital data is discussed. A 6-b A/D circuit is used to reduce the circuit size. Circuits that help maintain acceptable picture quality despite 6-b resolution were developed. Besides analog NTSC signal input and RGB signal output, the IC can also input and output digital NTSC signals, Y/C (luminance, chrominance) signals, and RGB signals. Applications of the LSI are presented  相似文献   
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The experiment we conducted for integrated digital satellite communications is aimed at realizing integrated services digital networks by satellite communication. The experiment was carried out in 1980 using the Japanese experimental communication satellite "CS." This experiment uses 30/20 GHz small earth stations and demand-assignment time-division multiple-access (TDMA) systems. Communications between customer terminals, which contain video conferencing, high-speed facsimile communication, high-speed computer communication, and packet-switching signal transmission, were carried out through the experimental digital satellite link. This paper describes the configuration of the experimental integrated digital satellite communications system and the experimental results of communications between customer terminals.  相似文献   
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This paper presents our insights into so-called personal communication and describes a conceptual proposal of radio access, which connects terminals with network services. Firstly, personal communication services are classified into basic (personal connection) services and advanced (personalized) services. Based on this categorization, features of the Japanese Personal Handy Phone (PHP) system, which offers services in homes, offices, and outdoor environments using a small cordless telephone terminal, are presented. The PHP system is defined here as a combination of three functional elements: a digital cordless terminal, radio access, and intelligent network. Secondly, the PHP system is described in detail including service definition, system design, network configuration, and evolutional scenario. Thirdly, we present standardization activities for the PHP-common air interface (CAI). The results of a three-month series of verification experiments, which have been successfully completed in 1992, are also explained. Based on the results, the specifications of PHP CAI were fixed at the end of 1992 through the cooperation of MPT, industries, and network operators. Technical items, mainly the 1.9-GHz 4-channel TDMA-TDD technology, are presented. Concerning R&D activities, the structure of frame synchronization for improving frequency utilization efficiency is described as one example of the many technical breakthroughs made in developing the PHP system. Finally, general considerations on service aspects of the PHP system are presented. This section includes comparisons between PHP and cellular systems from service viewpoints, such as charging, terminal performance, and service coverage area. The important results demonstrate the possibility of the coexistence of and the prosperity of both systems, due to the spread of the outdoor communication market caused by the introduction of the economical PHP system. In addition, our view on the phased approach for future service integration is given.  相似文献   
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