The unmanned aerial vehicle(UAV)images captured under low-light conditions are often suffering from noise and uneven illumination.To address these issues,we propose a low-light image enhancement algorithm for UAV imag...The unmanned aerial vehicle(UAV)images captured under low-light conditions are often suffering from noise and uneven illumination.To address these issues,we propose a low-light image enhancement algorithm for UAV images,which is inspired by the Retinex theory and guided by a light weighted map.Firstly,we propose a new network for reflectance component processing to suppress the noise in images.Secondly,we construct an illumination enhancement module that uses a light weighted map to guide the enhancement process.Finally,the processed reflectance and illumination components are recombined to obtain the enhancement results.Experimental results show that our method can suppress the noise in images while enhancing image brightness,and prevent over enhancement in bright regions.Code and data are available at https://gitee.com/baixiaotong2/uav-images.git.展开更多
The QTL qTGW3-1 was located on chromosome 3 of rice （Oryza sativa L.） and associated with the 1 000-grain weight （TGW） according to the result of our earlier study. With the objective of fine mapping of this locus...The QTL qTGW3-1 was located on chromosome 3 of rice （Oryza sativa L.） and associated with the 1 000-grain weight （TGW） according to the result of our earlier study. With the objective of fine mapping of this locus, we developed a F2 population consisting of 3 428 plants derived from the cross between TGW-related near isogenic line DL017 （BC3F4 generation of GSL 156×Nipponbare） and the recurrent parent Nipponbare. Using six microsatellites, this QTL was delimited between RM5477 and RM6417. Markers MM 1455 and MM 1456 within this region were used for further mapping of this QTL. Finally, qTGW3-1 was fine-mapped into a 89-kb interval between RM5477 and MM1456, which locates in the BAC clone AC107226 harboring five putative candidate genes.展开更多
Thousand-grain weight (TGW) is a key component of grain yield in rice. This study was conducted to validate and fine-map qTGW1.2a, a quantitative trait locus for grain weight and grain size previously located in a 933...Thousand-grain weight (TGW) is a key component of grain yield in rice. This study was conducted to validate and fine-map qTGW1.2a, a quantitative trait locus for grain weight and grain size previously located in a 933.6-kb region on the long arm of rice chromosome 1. Firstly, three residual heterozygotes (RHs) were selected from a BC2F11 population of the indica rice cross Zhenshan 97 (ZS97)///ZS97//ZS97/Milyang 46. The heterozygous segments in these RHs were arranged successively in physical positions, forming one set of sequential residual heterozygotes (SeqRHs). In each of the populations derived, non-recombinant homozygotes were identified to produce near isogenic lines (NILs) comprising the two homozygous genotypes. The NILs were tested for grain weight, grain length and grain width. QTL analyses for the three traits were performed. Then, the updated QTL location was followed for a new run of SeqRHs identification-NIL development-QTL mapping. Altogether, 11 NIL populations derived from four sets of SeqRHs were developed and used. qTGW1.2a was finally delimitated into a 77.5-kb region containing 13 annotated genes. In the six populations segregating this QTL, which were in four generations and were tested across four years, the allelic direction of qTGW1.2a remained consistent and the genetic effects were stable. For TGW, the additive effects ranged from 0.23 to 0.38 g and the proportions of phenotypic variance explained ranged from 26.15% to 41.65%. These results provide a good foundation for the cloning and functional analysis of qTGW1.2a.展开更多
A backcrossed population （BC1） derived from a cross between C100 and Dazao was obtained. The quantitative trait loci （QTLs） of the economically important traits for whole cocoon weight, cocoon shell weight, ratio ...A backcrossed population （BC1） derived from a cross between C100 and Dazao was obtained. The quantitative trait loci （QTLs） of the economically important traits for whole cocoon weight, cocoon shell weight, ratio of cocoon shell and weight of pupae, etc., were analyzed for the first time using the multiple interval mapping software WinQTLCart2.0. In total 40 QTLs were detected and contributed to 21 groups based on the constructed linkage map. According to the mapping results, 2, 2, 3, and 2 major QTLs explained over 20% of total phenotypic variations, whereas four QTLs, namely qCW-19, qSW-2, qCSR-4, and qPW-23, explained more than 30% of total phenotypic variations for whole cocoon weight, cocoon shell weight, ratio of cocoon shell and weight of pupae, respectively. Correlated traits QTLs often share the same location. Furthermore, most of the detected QTLs were closed to one-side marker. By using the very closed markers, positive QTLs can be aggregated, which can form a basis for molecular marker-assisted selection and breeding.展开更多
Grain weight is one of themost important determinants of grain yield in rice.In this study,QTL analysis for grain weight,grain length,and grainwidthwas performed using populations derived from crosses between major pa...Grain weight is one of themost important determinants of grain yield in rice.In this study,QTL analysis for grain weight,grain length,and grainwidthwas performed using populations derived from crosses between major parental lines of three-line indica hybrid rice.A total of 27 QTL for grain weight were detected using three recombinant inbred line populations derived from the crosses Teqing/IRBB lines,Zhenshan 97/Milyang 46,and Xieqingzao/Milyang 46.Of these,10 were found in only a single population and the other 17 in two or all three populations.Nine of the 17 common QTL were located in regions where no QTL associated with grain weight have been cloned and onewas selected for fine-mapping.Eight populations segregating in an isogenic background were derived from one F7 residual heterozygote of Teqing/IRBB52.The target QTL,qTGW10-20.8 controlling grain weight,grain length,and grain width,was localized to a 70.7-kb region flanked by InDel markers Te20811 and Te20882 on the long arm of chromosome 10.The QTL region contains seven annotated genes,ofwhich six encode proteins with known functional domains and one encodes a hypothetical protein.One of the genes,Os10g0536100 encoding the MIKC-type MADS-box protein OsMADS56,is the most likely candidate for qTGW10-20.8.These results provide a basis for cloning qTGW10-20.8,which has an important contribution to grain weight variation in rice.展开更多
To provide new experimental materials for QTL analysis of rice yield trait, we constructed a mapping population of 150 1ines （recombination inbred lines, R1L） derived from a cross between rice varieties V20B and CPS...To provide new experimental materials for QTL analysis of rice yield trait, we constructed a mapping population of 150 1ines （recombination inbred lines, R1L） derived from a cross between rice varieties V20B and CPSLO17, and localized QTLs and evaluated the genetic effects in the two parents and 150 RILs for thousand-grain weight trait by using internal mapping method of software MapQTL5 combining thousand-grain weight phenotypic data of the RILs. The results showed that a new QTL （qTGW-3） related to thousand-grain weight trait was detected. Individual QTL （LOD=4.14） explained 11.9% of the observed phenotypic variance. And the QTL alleles came from the parent V20B.展开更多
In response to the problem of inter-carrier interference(ICI)and inter-subband interference(IBI)in the received signals of universal filtered multi-carrier(UFMC)systems,a novel interfer-ence suppression design scheme ...In response to the problem of inter-carrier interference(ICI)and inter-subband interference(IBI)in the received signals of universal filtered multi-carrier(UFMC)systems,a novel interfer-ence suppression design scheme applying the method of complex weighted matrix inter-leaving map-ping(CWMIM)is proposed on the basis of the existing suppression scheme of conjugate weighted butterfly interleaving mapping(CWBIM).The proposed scheme performs matrix interleaving map-ping on the transmitted signal,which not only improves the carrier interference ratio(CIR)of the received signal by combining the original IBI and ICI terms,but also further inhibits the probability of burst error in the received signal.Meanwhile,the scheme can further decrease the impact of phase rotation errors in the received signal by increasing the number of rotation factors.Theoretical analysis and simulation results demonstrate that compared with CWBIM-UFMC,the proposed CWMIM-UFMC can obtain more effective ICI and IBI suppression and better system bit error rate(BER)performance with only a little bit increase in computational complexity.展开更多
Background: Liver weight is a complex trait, controlled by polygenic factors and differs within populations. Dissecting the genetic architecture underlying these variations will facilitate the search for key role cand...Background: Liver weight is a complex trait, controlled by polygenic factors and differs within populations. Dissecting the genetic architecture underlying these variations will facilitate the search for key role candidate genes involved directly in the hepatomegaly process and indirectly involved in related diseases etiology.Methods: Liver weight of 506 mice generated from 39 different Collaborative Cross(CC) lines with both sexes at age 20 weeks old was determined using an electronic balance. Genomic DNA of the CC lines was genotyped with high-density single nucleotide polymorphic markers.Results: Statistical analysis revealed a significant(P < 0.05) variation of liver weight between the CC lines, with broad sense heritability(H^2) of 0.32 and genetic coefficient of variation(CV_G) of 0.28. Subsequently, quantitative trait locus(QTL) mapping was performed, and results showed a significant QTL only for females on chromosome 8 at genomic interval 88.61-93.38 Mb(4.77 Mb). Three suggestive QTL were mapped at chromosomes 4, 12 and 13. The four QTL were designated as LWL1-LWL4 referring to liver weight loci 1-4 on chromosomes 8, 4, 12 and 13,respectively.Conclusion: To our knowledge, this report presents, for the first time, the utilization of the CC for mapping QTL associated with baseline liver weight in mice. Our findings demonstrate that liver weight is a complex trait controlled by multiple genetic factors that differ significantly between sexes.展开更多
The purpose of this paper is to investigate the feasibility of using a similarity coefficient map（SCM） in improving the morphological evaluation of T2＊ weighted（T2＊W） magnatic resonance imaging（MRI） for renal ...The purpose of this paper is to investigate the feasibility of using a similarity coefficient map（SCM） in improving the morphological evaluation of T2＊ weighted（T2＊W） magnatic resonance imaging（MRI） for renal cancer.Simulation studies and in vivo 12-echo T2＊W experiments for renal cancers were performed for this purpose.The results of the first simulation study suggest that an SCM can reveal small structures which are hard to distinguish from the background tissue in T2＊W images and the corresponding T2＊ map.The capability of improving the morphological evaluation is likely due to the improvement in the signal-to-noise ratio（SNR） and the carrier-to-noise ratio（CNR） by using the SCM technique.Compared with T2＊ W images,an SCM can improve the SNR by a factor ranging from 1.87 to 2.47.Compared with T2＊ maps,an SCM can improve the SNR by a factor ranging from 3.85 to 33.31.Compared with T2＊W images,an SCM can improve the CNR by a factor ranging from 2.09 to 2.43.Compared with T2＊ maps,an SCM can improve the CNR by a factor ranging from 1.94 to 8.14.For a given noise level,the improvements of the SNR and the CNR depend mainly on the original SNRs and CNRs in T2＊W images,respectively.In vivo experiments confirmed the results of the first simulation study.The results of the second simulation study suggest that more echoes are used to generate the SCM,and higher SNRs and CNRs can be achieved in SCMs.In conclusion,an SCM can provide improved morphological evaluation of T2＊W MR images for renal cancer by unveiling fine structures which are ambiguous or invisible in the corresponding T2＊W MR images and T2＊ maps.Furthermore,in practical applications,for a fixed total sampling time,one should increase the number of echoes as much as possible to achieve SCMs with better SNRs and CNRs.展开更多
Tens of thousands of landslides were triggered by May 12, 2008 earthquake over a broad area. The main purpose of this article is to apply and verify earthquake-triggered landslide hazard analysis techniques by using w...Tens of thousands of landslides were triggered by May 12, 2008 earthquake over a broad area. The main purpose of this article is to apply and verify earthquake-triggered landslide hazard analysis techniques by using weight of evidence modeling in Qingshui （清水） River watershed, Deyang （德阳） City, Sichuan （四川） Province, China. Two thousand three hundred and twenty-one landslides were interpreted in the study area from aerial photographs and multi-source remote sensing imageries post-earthquake, verified by field surveys. The landslide inventory in the study area was established. A spatial database, including landslides and associated controlling parameters that may have influence on the occurrence of landslides, was constructed from topographic maps, geological maps, and enhanced thematic mapper （ETM＋） remote sensing imageries. The factors that influence landslide occurrence,such as slope angle, aspect, curvature, elevation, flow accumulation, distance from drainages, and distance from roads were calculated from the topographic maps. Lithology, distance from seismogenic fault, distance from all faults, and distance from stratigraphic boundaries were derived from the geological maps. Normalized difference vegetation index （NDV1） was extracted from ETM＋ images. Seismic intensity zoning was collected from Wenchuan （汶川） Ms8.0 Earthquake Intensity Distribution Map published by the China Earthquake Administration.Landslide hazard indices were calculated using the weight of evidence model, and landslide hazard maps were calculated from using different controlling parameters cases. The hazard map was compared with known landslide locations and verified. The success accuracy percentage of using all 13 controlling parameters was 71.82%. The resulting landslide hazard map showed five classes of landslide hazard, i.e., very high, high, moderate, low, and very low. The validation results showed satisfactory agreement between the hazard map and the existing landslides distribution data. The landslide hazard map can be used to identify and delineate unstable hazard-prone areas. It can also help planners to choose favorable locations for development schemes, such as infrastructural, buildings, road constructions, and environmental protection.展开更多
Purpose To evaluate the performance of diffusion-weighted imaging(DWI) and variable flip angle(VFA) T1 mapping as a supplement to image-guided biopsy in follow-up analysis of liver fibrosis. Materials and Methods This...Purpose To evaluate the performance of diffusion-weighted imaging(DWI) and variable flip angle(VFA) T1 mapping as a supplement to image-guided biopsy in follow-up analysis of liver fibrosis. Materials and Methods This prospective study was approved by the institution's committee on human research, and written informed consent was provided from the enrolled patients. We investigated five MRI parameters of DWI and VFA T1 mapping, collected from 11 patients who underwent serial ultrasound image-guided biopsy with follow-up MRI within 1.5 years after treatment for liver fibrosis/cirrhosis. For each patient, four consecutive MRI examinations were conducted, including baseline MRI before treatment and three follow-up MRI examinations after treatment at each 0.5-year interval. ADC values at four b values and T1 relaxation times were correlated to pathology-confirmed liver fibrosis stages, which were subsequently divided into two groups, stages F2–3 and F4. The receiver operating characteristic(ROC) analysis and repeated measurement analysis of variance were used for statistical analysis. Results Among these ADC parameters, ADC value(b = 500 s/mm^2) was the most consistent in differentiating between stage F2–3 and F4 liver fibrosis. Repeated measurement analysis showed that the intra-group and inter-group differences were 0.447 and 0.024, respectively. T1 relaxation time could not consistently differentiate between the F2–3 and F4 groups; however, it was repeatable, and the intra-group and inter-group differences were 0.410 and 0.042, respectively. Conclusion MRI-ADC value at a b value of 500 s/mm^2 can be a promising biomarker for differentiating stages F2–3 and F4 liver fibrosis. A combination of this biomarker with repeatable T1 relaxation time may function as a non-invasive tool for follow-up liver fibrosis in patients who reject repeated image-guided biopsy.展开更多
An ill-posed inverse problem in quantitative susceptibility mapping （QSM） is usually solved using a regularization and optimization solver, which is time consuming considering the three-dimensional volume data. Howe...An ill-posed inverse problem in quantitative susceptibility mapping （QSM） is usually solved using a regularization and optimization solver, which is time consuming considering the three-dimensional volume data. However, in clinical diagnosis, it is necessary to reconstruct a susceptibility map efficiently with an appropriate method. Here, a modified QSM reconstruction method called weighted total variation using split Bregman （WTVSB） is proposed. It reconstructs the susceptibility map with fast computational speed and effective artifact suppression by incorporating noise-suppressed data weighting with split Bregman iteration. The noise-suppressed data weighting is determined using the Laplacian of the calculated local field, which can prevent the noise and errors in field maps from spreading into the susceptibility inversion. The split Bregman iteration accelerates the solution of the Ll-regularized reconstruction model by utilizing a preconditioned conjugate gradient solver. In an experiment, the proposed reconstruction method is compared with truncated k-space division （TKD）, morphology enabled dipole inversion （MEDI）, total variation using the split Bregman （TVSB） method for numerical simulation, phantom and in vivo human brain data evaluated by root mean square error and mean structure similarity. Experimental results demonstrate that our proposed method can achieve better balance between accuracy and efficiency of QSM reconstruction than conventional methods, and thus facilitating clinical applications of QSM.展开更多
基金supported by the National Natural Science Foundation of China(Nos.62201454 and 62306235)the Xi’an Science and Technology Program of Xi’an Science and Technology Bureau(No.23SFSF0004)。
文摘The unmanned aerial vehicle(UAV)images captured under low-light conditions are often suffering from noise and uneven illumination.To address these issues,we propose a low-light image enhancement algorithm for UAV images,which is inspired by the Retinex theory and guided by a light weighted map.Firstly,we propose a new network for reflectance component processing to suppress the noise in images.Secondly,we construct an illumination enhancement module that uses a light weighted map to guide the enhancement process.Finally,the processed reflectance and illumination components are recombined to obtain the enhancement results.Experimental results show that our method can suppress the noise in images while enhancing image brightness,and prevent over enhancement in bright regions.Code and data are available at https://gitee.com/baixiaotong2/uav-images.git.
基金supported by the National Basic Research Program of China (2010CB129504)the National Key Technologies R&D Program of China (2009BADA2B01)the 948 Project of MOA, China (2011-G2B)
文摘The QTL qTGW3-1 was located on chromosome 3 of rice （Oryza sativa L.） and associated with the 1 000-grain weight （TGW） according to the result of our earlier study. With the objective of fine mapping of this locus, we developed a F2 population consisting of 3 428 plants derived from the cross between TGW-related near isogenic line DL017 （BC3F4 generation of GSL 156×Nipponbare） and the recurrent parent Nipponbare. Using six microsatellites, this QTL was delimited between RM5477 and RM6417. Markers MM 1455 and MM 1456 within this region were used for further mapping of this QTL. Finally, qTGW3-1 was fine-mapped into a 89-kb interval between RM5477 and MM1456, which locates in the BAC clone AC107226 harboring five putative candidate genes.
基金funded by the National Key R&D Program of China (Grant No. 2017YFD0100305)the National Natural Science Foundation of China (Grant No. 31521064)a project of the China National Rice Research Institute (Grant No. 2017RG001-2)
文摘Thousand-grain weight (TGW) is a key component of grain yield in rice. This study was conducted to validate and fine-map qTGW1.2a, a quantitative trait locus for grain weight and grain size previously located in a 933.6-kb region on the long arm of rice chromosome 1. Firstly, three residual heterozygotes (RHs) were selected from a BC2F11 population of the indica rice cross Zhenshan 97 (ZS97)///ZS97//ZS97/Milyang 46. The heterozygous segments in these RHs were arranged successively in physical positions, forming one set of sequential residual heterozygotes (SeqRHs). In each of the populations derived, non-recombinant homozygotes were identified to produce near isogenic lines (NILs) comprising the two homozygous genotypes. The NILs were tested for grain weight, grain length and grain width. QTL analyses for the three traits were performed. Then, the updated QTL location was followed for a new run of SeqRHs identification-NIL development-QTL mapping. Altogether, 11 NIL populations derived from four sets of SeqRHs were developed and used. qTGW1.2a was finally delimitated into a 77.5-kb region containing 13 annotated genes. In the six populations segregating this QTL, which were in four generations and were tested across four years, the allelic direction of qTGW1.2a remained consistent and the genetic effects were stable. For TGW, the additive effects ranged from 0.23 to 0.38 g and the proportions of phenotypic variance explained ranged from 26.15% to 41.65%. These results provide a good foundation for the cloning and functional analysis of qTGW1.2a.
文摘A backcrossed population （BC1） derived from a cross between C100 and Dazao was obtained. The quantitative trait loci （QTLs） of the economically important traits for whole cocoon weight, cocoon shell weight, ratio of cocoon shell and weight of pupae, etc., were analyzed for the first time using the multiple interval mapping software WinQTLCart2.0. In total 40 QTLs were detected and contributed to 21 groups based on the constructed linkage map. According to the mapping results, 2, 2, 3, and 2 major QTLs explained over 20% of total phenotypic variations, whereas four QTLs, namely qCW-19, qSW-2, qCSR-4, and qPW-23, explained more than 30% of total phenotypic variations for whole cocoon weight, cocoon shell weight, ratio of cocoon shell and weight of pupae, respectively. Correlated traits QTLs often share the same location. Furthermore, most of the detected QTLs were closed to one-side marker. By using the very closed markers, positive QTLs can be aggregated, which can form a basis for molecular marker-assisted selection and breeding.
基金supported by the National Key Research and Development Program of China (2016YFD0101104)the National Natural Science Foundation of China (31521064)project of the China National Rice Research Institute (2017RG001-2)
文摘Grain weight is one of themost important determinants of grain yield in rice.In this study,QTL analysis for grain weight,grain length,and grainwidthwas performed using populations derived from crosses between major parental lines of three-line indica hybrid rice.A total of 27 QTL for grain weight were detected using three recombinant inbred line populations derived from the crosses Teqing/IRBB lines,Zhenshan 97/Milyang 46,and Xieqingzao/Milyang 46.Of these,10 were found in only a single population and the other 17 in two or all three populations.Nine of the 17 common QTL were located in regions where no QTL associated with grain weight have been cloned and onewas selected for fine-mapping.Eight populations segregating in an isogenic background were derived from one F7 residual heterozygote of Teqing/IRBB52.The target QTL,qTGW10-20.8 controlling grain weight,grain length,and grain width,was localized to a 70.7-kb region flanked by InDel markers Te20811 and Te20882 on the long arm of chromosome 10.The QTL region contains seven annotated genes,ofwhich six encode proteins with known functional domains and one encodes a hypothetical protein.One of the genes,Os10g0536100 encoding the MIKC-type MADS-box protein OsMADS56,is the most likely candidate for qTGW10-20.8.These results provide a basis for cloning qTGW10-20.8,which has an important contribution to grain weight variation in rice.
基金Supported by Sub-project of the 2017 National Key Research and Development Program(2017YFD0100402,2017YFD0100204)Guizhou Science and Technology Major Project[QKHZDZXZ(2012)6005]+2 种基金Program for Research Institutions to Serve Enterprises in Guizhou Province[QKHPTRC(2017)5719]Guizhou Modern Agriculture Technology System(GZCYTX2018-06)Guizhou Science and Technology Major Project(GZCYTX2018-06)
文摘To provide new experimental materials for QTL analysis of rice yield trait, we constructed a mapping population of 150 1ines （recombination inbred lines, R1L） derived from a cross between rice varieties V20B and CPSLO17, and localized QTLs and evaluated the genetic effects in the two parents and 150 RILs for thousand-grain weight trait by using internal mapping method of software MapQTL5 combining thousand-grain weight phenotypic data of the RILs. The results showed that a new QTL （qTGW-3） related to thousand-grain weight trait was detected. Individual QTL （LOD=4.14） explained 11.9% of the observed phenotypic variance. And the QTL alleles came from the parent V20B.
基金Supported by the National Natural Science Foundation of China(No.61601296,61201244)the Science and Technology Innovation Action Plan Project of Shanghai Science and Technology Commission(No.20511103500)the Talent Program of Shanghai University of Engineer-ing Science(No.2018RC43).
文摘In response to the problem of inter-carrier interference(ICI)and inter-subband interference(IBI)in the received signals of universal filtered multi-carrier(UFMC)systems,a novel interfer-ence suppression design scheme applying the method of complex weighted matrix inter-leaving map-ping(CWMIM)is proposed on the basis of the existing suppression scheme of conjugate weighted butterfly interleaving mapping(CWBIM).The proposed scheme performs matrix interleaving map-ping on the transmitted signal,which not only improves the carrier interference ratio(CIR)of the received signal by combining the original IBI and ICI terms,but also further inhibits the probability of burst error in the received signal.Meanwhile,the scheme can further decrease the impact of phase rotation errors in the received signal by increasing the number of rotation factors.Theoretical analysis and simulation results demonstrate that compared with CWBIM-UFMC,the proposed CWMIM-UFMC can obtain more effective ICI and IBI suppression and better system bit error rate(BER)performance with only a little bit increase in computational complexity.
基金Israeli Centers of Research ExcellenceWellcome Trust,Grant/Award Number:085906/Z/08/Z,075491/Z/04,090532/Z/09/Z+1 种基金Edmond J.Safra Center for Bioinformatics at Tel-Aviv UniversityTel-Aviv University
文摘Background: Liver weight is a complex trait, controlled by polygenic factors and differs within populations. Dissecting the genetic architecture underlying these variations will facilitate the search for key role candidate genes involved directly in the hepatomegaly process and indirectly involved in related diseases etiology.Methods: Liver weight of 506 mice generated from 39 different Collaborative Cross(CC) lines with both sexes at age 20 weeks old was determined using an electronic balance. Genomic DNA of the CC lines was genotyped with high-density single nucleotide polymorphic markers.Results: Statistical analysis revealed a significant(P < 0.05) variation of liver weight between the CC lines, with broad sense heritability(H^2) of 0.32 and genetic coefficient of variation(CV_G) of 0.28. Subsequently, quantitative trait locus(QTL) mapping was performed, and results showed a significant QTL only for females on chromosome 8 at genomic interval 88.61-93.38 Mb(4.77 Mb). Three suggestive QTL were mapped at chromosomes 4, 12 and 13. The four QTL were designated as LWL1-LWL4 referring to liver weight loci 1-4 on chromosomes 8, 4, 12 and 13,respectively.Conclusion: To our knowledge, this report presents, for the first time, the utilization of the CC for mapping QTL associated with baseline liver weight in mice. Our findings demonstrate that liver weight is a complex trait controlled by multiple genetic factors that differ significantly between sexes.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB707701)the National Key Technology R&D Program of China(Grant Nos. 2011BAI12B05 and 2012BAI23B07)
文摘The purpose of this paper is to investigate the feasibility of using a similarity coefficient map（SCM） in improving the morphological evaluation of T2＊ weighted（T2＊W） magnatic resonance imaging（MRI） for renal cancer.Simulation studies and in vivo 12-echo T2＊W experiments for renal cancers were performed for this purpose.The results of the first simulation study suggest that an SCM can reveal small structures which are hard to distinguish from the background tissue in T2＊W images and the corresponding T2＊ map.The capability of improving the morphological evaluation is likely due to the improvement in the signal-to-noise ratio（SNR） and the carrier-to-noise ratio（CNR） by using the SCM technique.Compared with T2＊ W images,an SCM can improve the SNR by a factor ranging from 1.87 to 2.47.Compared with T2＊ maps,an SCM can improve the SNR by a factor ranging from 3.85 to 33.31.Compared with T2＊W images,an SCM can improve the CNR by a factor ranging from 2.09 to 2.43.Compared with T2＊ maps,an SCM can improve the CNR by a factor ranging from 1.94 to 8.14.For a given noise level,the improvements of the SNR and the CNR depend mainly on the original SNRs and CNRs in T2＊W images,respectively.In vivo experiments confirmed the results of the first simulation study.The results of the second simulation study suggest that more echoes are used to generate the SCM,and higher SNRs and CNRs can be achieved in SCMs.In conclusion,an SCM can provide improved morphological evaluation of T2＊W MR images for renal cancer by unveiling fine structures which are ambiguous or invisible in the corresponding T2＊W MR images and T2＊ maps.Furthermore,in practical applications,for a fixed total sampling time,one should increase the number of echoes as much as possible to achieve SCMs with better SNRs and CNRs.
基金supported by the International Scientific Joint Project of China (No. 2009DFA21280)the National Natural Science Foundation of China (No. 40821160550)the Doctoral Candidate Innovation Research Support Program by Science & Technology Review (No. kjdb200902-5)
文摘Tens of thousands of landslides were triggered by May 12, 2008 earthquake over a broad area. The main purpose of this article is to apply and verify earthquake-triggered landslide hazard analysis techniques by using weight of evidence modeling in Qingshui （清水） River watershed, Deyang （德阳） City, Sichuan （四川） Province, China. Two thousand three hundred and twenty-one landslides were interpreted in the study area from aerial photographs and multi-source remote sensing imageries post-earthquake, verified by field surveys. The landslide inventory in the study area was established. A spatial database, including landslides and associated controlling parameters that may have influence on the occurrence of landslides, was constructed from topographic maps, geological maps, and enhanced thematic mapper （ETM＋） remote sensing imageries. The factors that influence landslide occurrence,such as slope angle, aspect, curvature, elevation, flow accumulation, distance from drainages, and distance from roads were calculated from the topographic maps. Lithology, distance from seismogenic fault, distance from all faults, and distance from stratigraphic boundaries were derived from the geological maps. Normalized difference vegetation index （NDV1） was extracted from ETM＋ images. Seismic intensity zoning was collected from Wenchuan （汶川） Ms8.0 Earthquake Intensity Distribution Map published by the China Earthquake Administration.Landslide hazard indices were calculated using the weight of evidence model, and landslide hazard maps were calculated from using different controlling parameters cases. The hazard map was compared with known landslide locations and verified. The success accuracy percentage of using all 13 controlling parameters was 71.82%. The resulting landslide hazard map showed five classes of landslide hazard, i.e., very high, high, moderate, low, and very low. The validation results showed satisfactory agreement between the hazard map and the existing landslides distribution data. The landslide hazard map can be used to identify and delineate unstable hazard-prone areas. It can also help planners to choose favorable locations for development schemes, such as infrastructural, buildings, road constructions, and environmental protection.
文摘Purpose To evaluate the performance of diffusion-weighted imaging(DWI) and variable flip angle(VFA) T1 mapping as a supplement to image-guided biopsy in follow-up analysis of liver fibrosis. Materials and Methods This prospective study was approved by the institution's committee on human research, and written informed consent was provided from the enrolled patients. We investigated five MRI parameters of DWI and VFA T1 mapping, collected from 11 patients who underwent serial ultrasound image-guided biopsy with follow-up MRI within 1.5 years after treatment for liver fibrosis/cirrhosis. For each patient, four consecutive MRI examinations were conducted, including baseline MRI before treatment and three follow-up MRI examinations after treatment at each 0.5-year interval. ADC values at four b values and T1 relaxation times were correlated to pathology-confirmed liver fibrosis stages, which were subsequently divided into two groups, stages F2–3 and F4. The receiver operating characteristic(ROC) analysis and repeated measurement analysis of variance were used for statistical analysis. Results Among these ADC parameters, ADC value(b = 500 s/mm^2) was the most consistent in differentiating between stage F2–3 and F4 liver fibrosis. Repeated measurement analysis showed that the intra-group and inter-group differences were 0.447 and 0.024, respectively. T1 relaxation time could not consistently differentiate between the F2–3 and F4 groups; however, it was repeatable, and the intra-group and inter-group differences were 0.410 and 0.042, respectively. Conclusion MRI-ADC value at a b value of 500 s/mm^2 can be a promising biomarker for differentiating stages F2–3 and F4 liver fibrosis. A combination of this biomarker with repeatable T1 relaxation time may function as a non-invasive tool for follow-up liver fibrosis in patients who reject repeated image-guided biopsy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474236,81671674,and 11775184)the Science and Technology Project of Fujian Province,China(Grant No.2016Y0078)
文摘An ill-posed inverse problem in quantitative susceptibility mapping （QSM） is usually solved using a regularization and optimization solver, which is time consuming considering the three-dimensional volume data. However, in clinical diagnosis, it is necessary to reconstruct a susceptibility map efficiently with an appropriate method. Here, a modified QSM reconstruction method called weighted total variation using split Bregman （WTVSB） is proposed. It reconstructs the susceptibility map with fast computational speed and effective artifact suppression by incorporating noise-suppressed data weighting with split Bregman iteration. The noise-suppressed data weighting is determined using the Laplacian of the calculated local field, which can prevent the noise and errors in field maps from spreading into the susceptibility inversion. The split Bregman iteration accelerates the solution of the Ll-regularized reconstruction model by utilizing a preconditioned conjugate gradient solver. In an experiment, the proposed reconstruction method is compared with truncated k-space division （TKD）, morphology enabled dipole inversion （MEDI）, total variation using the split Bregman （TVSB） method for numerical simulation, phantom and in vivo human brain data evaluated by root mean square error and mean structure similarity. Experimental results demonstrate that our proposed method can achieve better balance between accuracy and efficiency of QSM reconstruction than conventional methods, and thus facilitating clinical applications of QSM.
