Colorectal cancer(CRC) is the third most commonly diagnosed cancer in the world and the fourth principal cause of cancer deaths worldwide. Currently, there is a lack of low cost and noninvasive screening tests for CRC...Colorectal cancer(CRC) is the third most commonly diagnosed cancer in the world and the fourth principal cause of cancer deaths worldwide. Currently, there is a lack of low cost and noninvasive screening tests for CRC, becoming a serious health problem. In this context, a potential biomarker for the early detection of CRC has recently gained attention. Circular RNAs(circ RNA), a re-discovered, abundant RNA specie, is a type of noncoding covalent closed RNAs formed from both exonic and intronic sequences. These circular molecules are widely expressed in cells, exceeding the abundance of the traditional linear m RNA transcript. They can regulate gene expression, acting as real sponges for mi RNAs and also regulate alternative splicing or act as transcriptional factors and inclusive encoding for proteins. However, little is known about circ RNA and its relationship with CRC. In this review, we focus on the biogenesis, function and role of these circ RNAs in relation to CRC, including their potential as a new biomarker.展开更多
In this paper, a new molecular computing model is developed to solve the maximum independent set problem, based on the method of DNA length reducing. To solve the maximum independent set problem with n-vertices and m-...In this paper, a new molecular computing model is developed to solve the maximum independent set problem, based on the method of DNA length reducing. To solve the maximum independent set problem with n-vertices and m-edges, the time complexity is O(n+m). With the enlargement of the problem scale, the numbers of the required tubes will increase linearly. Two important methods in this experiment are single strand DNA (ssDNA) circularization and DNA length reducing. In addition, using reverse polymerase chain reaction (PCR) and circligase, the structure of DNA molecules is changed in each computing step, transforming from linear double strand DNA (dsDNA) to linear ssDNA and circular ssDNA. Using the circular DNA structure, the recombina-tion among DNA molecules is avoided. To verify this computing model, a small maximum independent set problem was solved.展开更多
AIM:To evaluate the covalently closed circle DNA (cccDNA) level of hepatitis B virus (HBV) in patients' liver and sera. METHODS:HBV DNA was isolated from patients' liver biopsies and sera.A sensitive real-time...AIM:To evaluate the covalently closed circle DNA (cccDNA) level of hepatitis B virus (HBV) in patients' liver and sera. METHODS:HBV DNA was isolated from patients' liver biopsies and sera.A sensitive real-time PCR method,which is capable of differentiation of HBV viral genomic DNA and cccDNA,was used to quantify the total HBV cccDNA.The total HBV viral DNA was quantitated by real-time PCR using a HBV diagnostic kit (PG Biotech,LTD,Shenzhen,China) described previously. RESULTS:For the first time,we measured the level of HBV DNA and cccDNA isolated from ten HBV patients' liver biopsies and sera.In the liver biopsies,cccDNA was detected from all the biopsy samples.The copy number of cccDNA ranged from from 0.03 to 173.1 per cell,the copy number of total HBV DNA ranged from 0.08 to 3 717 per cell.The ratio of total HBV DNA to cccDNA ranged from 1 to 3 406.In the sera, cccDNA was only detected from six samples whereas HBV viral DNA was detected from all ten samples.The ratio of cccDNA to total HBV DNA ranged from 0 to 1.77%.To further investigate the reason why cccDNA could only be detected in some patients' sera,we performed longitudinal studies.The cccDNA was detected from the patients' sera with HBV reactivation but not from the patients' sera without HBV reactivation.The level of cccDNA in the sera was correlated with ALT and viral load in the HBV reactivation patients. CONCLUSION:HBV cccDNA is actively transcribed and replicated in some patients' hepatoo/tes,which is reflected by a high ratio of HBV total DNA vs cccDNA.Detection of cccDNA in the liver biopsy will provide an end-point for the anti-HBV therapy.The occurrence of cccDNA in the sera is an early signal of liver damage,which may be another important clinical parameter.展开更多
The integrated extraction of coal and gas combines coal mining with gas capture. Taking into account the gas deposition and flow conditions in the Chinese coal basins, this paper describes the status of the theory and...The integrated extraction of coal and gas combines coal mining with gas capture. Taking into account the gas deposition and flow conditions in the Chinese coal basins, this paper describes the status of the theory and key technologies of this integrated extraction system, and presents its application and practice in the Shaqu, Zhongxing, Fenghuangshan and Pingmei mines. Areas for further improvements in future studies are discussed, focusing in particular on the fundamentals of the extraction system to make it greener, more scientific, and more advanced in both the exploitation and utilization of coal and the gas in coal.展开更多
文摘Colorectal cancer(CRC) is the third most commonly diagnosed cancer in the world and the fourth principal cause of cancer deaths worldwide. Currently, there is a lack of low cost and noninvasive screening tests for CRC, becoming a serious health problem. In this context, a potential biomarker for the early detection of CRC has recently gained attention. Circular RNAs(circ RNA), a re-discovered, abundant RNA specie, is a type of noncoding covalent closed RNAs formed from both exonic and intronic sequences. These circular molecules are widely expressed in cells, exceeding the abundance of the traditional linear m RNA transcript. They can regulate gene expression, acting as real sponges for mi RNAs and also regulate alternative splicing or act as transcriptional factors and inclusive encoding for proteins. However, little is known about circ RNA and its relationship with CRC. In this review, we focus on the biogenesis, function and role of these circ RNAs in relation to CRC, including their potential as a new biomarker.
基金The authors sincerely acknowledge the anonymous referee’s suggestions to this paper. This work was supported by the National Natural Science Foundation of China (Grant Nos. 60533010, 30670540, 60874036 and 60503002)National High-Tech Research and Development Program of China (Grant No. 2006AA01Z104)+1 种基金Ph.D. Programs Foundation of the Ministry of Education of China (Grant No. 20070001020)the Postdoctoral Science Foundation of China (Grant No. 20060400344)
文摘In this paper, a new molecular computing model is developed to solve the maximum independent set problem, based on the method of DNA length reducing. To solve the maximum independent set problem with n-vertices and m-edges, the time complexity is O(n+m). With the enlargement of the problem scale, the numbers of the required tubes will increase linearly. Two important methods in this experiment are single strand DNA (ssDNA) circularization and DNA length reducing. In addition, using reverse polymerase chain reaction (PCR) and circligase, the structure of DNA molecules is changed in each computing step, transforming from linear double strand DNA (dsDNA) to linear ssDNA and circular ssDNA. Using the circular DNA structure, the recombina-tion among DNA molecules is avoided. To verify this computing model, a small maximum independent set problem was solved.
基金SuppoSed by CRCG grant from the University of Hong KongCERG grant from University Grant Council of Hong Kong Research Fund from Science and Technology Commission of Shanghai,China
文摘AIM:To evaluate the covalently closed circle DNA (cccDNA) level of hepatitis B virus (HBV) in patients' liver and sera. METHODS:HBV DNA was isolated from patients' liver biopsies and sera.A sensitive real-time PCR method,which is capable of differentiation of HBV viral genomic DNA and cccDNA,was used to quantify the total HBV cccDNA.The total HBV viral DNA was quantitated by real-time PCR using a HBV diagnostic kit (PG Biotech,LTD,Shenzhen,China) described previously. RESULTS:For the first time,we measured the level of HBV DNA and cccDNA isolated from ten HBV patients' liver biopsies and sera.In the liver biopsies,cccDNA was detected from all the biopsy samples.The copy number of cccDNA ranged from from 0.03 to 173.1 per cell,the copy number of total HBV DNA ranged from 0.08 to 3 717 per cell.The ratio of total HBV DNA to cccDNA ranged from 1 to 3 406.In the sera, cccDNA was only detected from six samples whereas HBV viral DNA was detected from all ten samples.The ratio of cccDNA to total HBV DNA ranged from 0 to 1.77%.To further investigate the reason why cccDNA could only be detected in some patients' sera,we performed longitudinal studies.The cccDNA was detected from the patients' sera with HBV reactivation but not from the patients' sera without HBV reactivation.The level of cccDNA in the sera was correlated with ALT and viral load in the HBV reactivation patients. CONCLUSION:HBV cccDNA is actively transcribed and replicated in some patients' hepatoo/tes,which is reflected by a high ratio of HBV total DNA vs cccDNA.Detection of cccDNA in the liver biopsy will provide an end-point for the anti-HBV therapy.The occurrence of cccDNA in the sera is an early signal of liver damage,which may be another important clinical parameter.
文摘The integrated extraction of coal and gas combines coal mining with gas capture. Taking into account the gas deposition and flow conditions in the Chinese coal basins, this paper describes the status of the theory and key technologies of this integrated extraction system, and presents its application and practice in the Shaqu, Zhongxing, Fenghuangshan and Pingmei mines. Areas for further improvements in future studies are discussed, focusing in particular on the fundamentals of the extraction system to make it greener, more scientific, and more advanced in both the exploitation and utilization of coal and the gas in coal.
