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Identification and expression of a novel human testis-specific gene by digital differential display 被引量:4
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作者 李丹 卢光琇 《Chinese Medical Journal》 SCIE CAS CSCD 2004年第12期1791-1796,共6页
Background Evidence for the importance of genetic factors in male infertility is accumulating This study was designed to identify a novel testis specific gene related to spermatogenesis by a new strategy of digital di... Background Evidence for the importance of genetic factors in male infertility is accumulating This study was designed to identify a novel testis specific gene related to spermatogenesis by a new strategy of digital differential display (DDD) Methods Based on the generation of expressed sequenced tags (ESTs), comparing the testis libraries with other tissue or cell line libraries by the DDD program, we identified a new contig of the ESTs which were derived from testis libraries and represented a novel gene Multi tissue RT PCR was performed to analyse its tissue specific expression The full length cDNA of the new gene was obtained using the BLAST program Sequencing was performed and the result was analysed Semi quantitative RT PCR and Northern blot analyseis of mRNA from differential normal tissues were performed to clarify the expression pattern of the new gene The sequence of the opening reading frame was integrated into the pQE 30 vector expressed in Escherichia coil strain M15(pREP4) With IPTG induction, the target protein was detected Results A full length cDNA sequence of the new gene named SPATA12 (GeneBank accession number AY221117) in human testis was identified SPATA12 was 2430 bp in length, located in chromosome 3p21 1 3p21 2 The sequence of the opening reading frame was 676-1248 bp, as was confirmed by RT PCR and sequencing The cDNA encodes a novel protein of 190 amino acids with a theoretical molecular weight of 20 417 8 and isoelectric point of 5 23 The sequence has no significant homology with any known protein in databases Semi quantitative RT PCR and Northern blot analyses of multiple tissues showed that SPATA12 was expressed significantly in normal human testis The expression recombinant of SPATA12 was constructed and a high level of the histidine tagged fusion protein was obtained Conclusions DDD can be confirmed by SPATA12 as a novel computational biology based approach for identification of the testis specific expression genes SPATA12 may function as a testicular germ cell associated gene that plays some roles in spermatogenesis Moreover, a great amount of SPATA12 protein could be obtained by the gene recombination technique, thus providing a reliable foundation for investigating the biological function of this new protein 展开更多
关键词 cDNA cloning digital differential display TESTIS tissue specific expression E coil
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The J_2 invariant relative configuration of spaceborne SAR interferometer for digital elevation measurement
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作者 Ming Xu Ying-Hong Jia Shi-Jie Xu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第4期643-651,共9页
A 3-craft formation configuration is proposed to perform the digital elevation model (DEM) for the distributed spacebome interferometric synthetic aperture radar (InSAR), and it is optimized by the modified ant co... A 3-craft formation configuration is proposed to perform the digital elevation model (DEM) for the distributed spacebome interferometric synthetic aperture radar (InSAR), and it is optimized by the modified ant colony algorithm to have the best compatibility with J2 invariant orbits created by differential correction algorithm. The configuration has succeeded in assigning the across-track baseline to vary periodically and with its mean value equal to the optimal baseline determined by the relative height measurement accuracy. The required relationship between crafts' magnitudes and phases is formulated for the general case of interferometry measure from non-orthographic and non-lateral view. The J2 invariant configurations created by differential correction algorithm are employed to investigate their compatibility with the required configuration. The colony algorithm is applied to search the optimal configuration holding the near-constant across-track baseline under the J2 perturbation, and the absolute height measurement accuracy is preferable as expected. 展开更多
关键词 InSAR digital elevation model (DEM) J2 invariant orbit differential correction algorithm Formation flying
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Research on new software compensation method of static and quasi-static errors for precision motion controller
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作者 REN Kun FU Jian-zhong CHEN Zi-chen 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第12期1938-1943,共6页
To reduce mechanical vibrations induced by big errors compensation, a new software compensation method based on an improved digital differential analyzer (DDA) interpolator for static and quasi-static errors of machin... To reduce mechanical vibrations induced by big errors compensation, a new software compensation method based on an improved digital differential analyzer (DDA) interpolator for static and quasi-static errors of machine tools is proposed. Based on principle of traditional DDA interpolator, a DDA interpolator is divided into command generator and command analyzer. There are three types of errors, considering the difference of positions between compensation points and interpolation segments. According to the classification, errors are distributed evenly in data processing and compensated to certain interpolation segments in machining. On-line implementation results show that the proposed approach greatly improves positioning accuracy of computer numerical control (CNC) machine tools. 展开更多
关键词 Static and quasi-static errors Positioning and machining accuracy digital differential analyzer (DDA) interoolator
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A new method for high precsion instantaneous speedmeasurement of hydraulic system 被引量:1
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作者 LIU Jia-min GU Li-chen SUN Yu 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2019年第4期307-314,共8页
The instantaneous speed of a hydraulic system contains a wealth of operational information,and its accurate extraction is the basis for condition monitoring and fault diagnosis.In order to solve the problem of high ha... The instantaneous speed of a hydraulic system contains a wealth of operational information,and its accurate extraction is the basis for condition monitoring and fault diagnosis.In order to solve the problem of high hardware requirement for instantaneous speed measurement based on data acquisition card,a new method of high precision measurement is proposed.In this method,the time-displacement information of each tooth is obtained from the pulsed square wave signal of the gear disk collected by magnetoelectric sensors.The time-displacement curve is interpolated by the cubic spline interpolation method,and then the instantaneous speed is calculated by the five-point digital differential formula.The experimental results show that the method improves the speed measurement resolution and reduces the quantization error.The high precision instantaneous speed signal can also be acquired by hardware devices with less teeth and low sampling frequency.The related research results provide a theoretical basis and a method for improving the accuracy of instantaneous speed measurement. 展开更多
关键词 instantaneous speed measurement variable speed hydraulic system cubic spline interpolation five-point digital differentiation
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A digitally controlled PWM/PSM dual-mode DC/DC converter
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作者 甄少伟 张波 +3 位作者 罗萍 侯思剑 叶璟欣 马骁 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2011年第11期103-109,共7页
A digitally controlled pulse width modulation/pulse skip modulation (PWM/PSM) dual-mode buck DC/DC converter is proposed. Its operation mode can be automatically chosen as continuous conduction mode (CCM) or disco... A digitally controlled pulse width modulation/pulse skip modulation (PWM/PSM) dual-mode buck DC/DC converter is proposed. Its operation mode can be automatically chosen as continuous conduction mode (CCM) or discontinuous conduction mode (DCM). The converter works in PSM at DCM and in 2 MHz PWM at CCM. Switching loss is reduced at a light load by skipping cycles. Thus high conversion efficiency is realized in a wide load current. The implementations of PWM control blocks, such as the ADC, the digital pulse width modulator (DPWM) and the loop compensator, and PSM control blocks are described in detail. The parameters of the loop compensator can be programmed for different external component values and switching frequencies, which is much more flexible than its analog rivals. The chip is manufactured in 0.13 μm CMOS technology and the chip area is 1.21 mm^2. Experimental results show that the conversion efficiency is high, being 90% at 200 mA and 67% at 20 mA. Meanwhile, the measured load step response shows that the proposed dual-mode converter has good stability. 展开更多
关键词 digital power PSM ADC digital proportion integration differentiation DPWM BUCK
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