Over the past few years, the presence of steroid estrogens in the environment has become a major concern. In this study, the concentrations of estrone (El), 17β-estradinl (E2), and 17α-ethinyl estradiol (EE2) ...Over the past few years, the presence of steroid estrogens in the environment has become a major concern. In this study, the concentrations of estrone (El), 17β-estradinl (E2), and 17α-ethinyl estradiol (EE2) were measured in some wastewater treatment plants (WWTPs) in lran. These samples were collected from the municipal, rural, livestock, commercial, and hospital WWTPs, extracted by dispersive liquid-liquid micro extraction (DLLME) technique, derivatized, and detected by GC/MS. In these treatment plants, various processes including conven- tional activated sludge (CAS), aerated lagoon (AL), moving bed biofilm reactor (MBBR), and activated sludge with wetland (AS + WL) are used. The highest concentration of hormones was observed in the influents and effluents of livestock, municipal, commercial, and hospital WWTPs, respectively. The maximum elimination rate was obtained in MBBR followed by AS + WL CAS and AL The biodegradation and adsorption rates along with adsorption coefficients of 1g kd and 1g koc were measured for all target compounds.展开更多
AIM: To identify the role of herbal compound 861 (Cpd 861) in the regulation of mRNA expression of collagen synthesis- and degradation-related genes in human hepatic stellate cells (HSCs). METHODS: mRNA levels o...AIM: To identify the role of herbal compound 861 (Cpd 861) in the regulation of mRNA expression of collagen synthesis- and degradation-related genes in human hepatic stellate cells (HSCs). METHODS: mRNA levels of collagen types I and III, matrix metalloproteinase 1 (MMP-1), matrix metalloproteinase 2 (MMP-2), membrane type-1 matrix metalloproteinase (MT1-MMP), tissue inhibitor of metalloproteinase 1 (TIMP-1), and transforming growth factor β1 (TGF-β1) in cultured-activated HSCs treated with Cpd 861 or interferon-γ, (IFN-γ,) were determined by real-time PCR. RESULTS: Both Cpd 861 and IFN-γ reduced the mRNA levels of collagen type Ⅲ, MMP-2 and TGF-β1. Moreover, Cpd 861 significantly enhanced the MMP-1 mRNA levels while down-regulated the TIMP-1 mRNA expression, increasing the ratio of MMP-1 to TIMP-1 to (6.3 + 0.3)- fold compared to the control group. CONCLUSION: The anti-fibrosis function of Cpd 861 may be mediated by both decreased interstitial collagen sythesis by inhibiting the transcription of collagen type Ⅲ and TGF-β1 and increased degradation of these collagens by up-regulating MMP-1 and down-regulating TIMP-1 mRNA levels.展开更多
To extract region of interests (ROI) in brain magnetic resonance imaging (MRI) with more than two objects and improve the segmentation accuracy, a hybrid model of a kemel-based fuzzy c-means (KFCM) clustering al...To extract region of interests (ROI) in brain magnetic resonance imaging (MRI) with more than two objects and improve the segmentation accuracy, a hybrid model of a kemel-based fuzzy c-means (KFCM) clustering algorithm and Chan-Vese (CV) model for brain MRI segmentation is proposed. The approach consists of two succes- sive stages. Firstly, the KFCM is used to make a coarse segmentation, which achieves the automatic selection of initial contour. Then an improved CV model is utilized to subdivide the image. Fuzzy membership degree from KFCM clus- tering is incorporated into the fidelity term of the 2-phase piecewise constant CV model to obtain accurate multi-object segmentation. Experimental results show that the proposed model has advantages both in accuracy and in robustness to noise in comparison with fuzzy c-means (FCM) clustering, KFCM, and the hybrid model of FCM and CV on brain MRI segmentation.展开更多
Based on the data of NCEP, OLR and rainfall of China, we studied the influences of the East Asian winter monsoon activities on the precipitation during the raining season over China by correlation analysis and composi...Based on the data of NCEP, OLR and rainfall of China, we studied the influences of the East Asian winter monsoon activities on the precipitation during the raining season over China by correlation analysis and composite analysis. The result shows that annual and interdecadal change of East Asian winter monsoon is distinct. It is strong from 1950s to the middle of 1980s but weak after the middle of 1980s. The effect of abnormal winter monsoon on the precipitation during raining season is significant over the middle and lower reaches of the Changjiang River basin. It is revealed that the precipitation will increase when preceding winter monsoon is weak but decrease when preceding winter monsoon is strong. In this paper, some appropriate reasons are given to explain the abnormal rainfall by analyzing the distribution of SSTA and the variation of summer circulation. It is pointed out definitely that the variation of SSTA and summer circulation is a primary cause for abnormal rainfall over the middle and lower reaches of the Changjiang River.展开更多
The composition of HMW-GS and pentosan and its various component contents in different wheat varieties were analyzed. According to scores of these subunits in several wheat varieties, the correlation relationship betw...The composition of HMW-GS and pentosan and its various component contents in different wheat varieties were analyzed. According to scores of these subunits in several wheat varieties, the correlation relationship between the composition of HMW-GS, subunit combination types and pentosan, various components and component ratio were ascertained. The results showed that HMW-GSs were very diverse which had 11 types. In different varieties, the variation of Ara was obvious while Xyl was not; pentosan and its various component contents were very different, and their coefficient of variability was quite high. The majority of parameters had a significant negative correlation with Glu-1 where Glu-D1 was stronger than other two loci. N, 7, 17+18 and 2+12 subunits had influence on pentosan and its various component contents. But some subunits such as 1 and 5+ 10 which are good for baking quality had little contribution to pentosan and various component contents. The pentosan and various component contents were higher in the varieties which had (N, 7, 2+12) subunit combinations. Additionally, the 21 varieties were classified into 4 categories according to HMW-GS scores and pentosan content.展开更多
Type synthesis of lower-mobility parallel mechanisms is a hot and frontier topic in international academic and industrial field. Based on the Lie group theory, a displacement manifold synthesis method is proposed. For...Type synthesis of lower-mobility parallel mechanisms is a hot and frontier topic in international academic and industrial field. Based on the Lie group theory, a displacement manifold synthesis method is proposed. For all the nine kinds of lower-mobility parallel mechanisms, the mechanism displacement manifold, limb displacement manifold and the geometrical conditions which guarantee that the intersection of the limb displacement manifold is the desired mechanism displacement manifold are enumerated. Various limb kinematic chains can be obtained using the product closure of displacement subgroup. Parallel mechanisms can be constructed with these limbs while obeying the geometrical conditions. Hence, all the nine kinds of lower-mobility parallel mechanisms can be synthesized using this method. Since displacement manifold deals with finite motion, the result mechanism of synthesis have full-cycle mobility. Novel architectures of lower-mobility parallel mechanisms can be obtained using this method.展开更多
Cyclotides constitute a fascinating family of circular proteins containing ca.30 amino acid residues.They have a unique cyclic cysteine knot topology and exhibit remarkable thermal,chemical and enzymatic stabilities.T...Cyclotides constitute a fascinating family of circular proteins containing ca.30 amino acid residues.They have a unique cyclic cysteine knot topology and exhibit remarkable thermal,chemical and enzymatic stabilities.These characteristics enable them to have a range of biological activities and promising pharmaceutical and agricultural applications.Here,we present a practical strategy for the chemical synthesis of cyclotides through the intramolecular ligation of fully unprotected peptide O-esters.This strategy involves the mild Fmoc solid-phase peptide synthesis of the peptide O-ester backbone,the head-to-tail cyclization of the cyclotide backbone by native chemical ligation,and the oxidative refolding to yield the natural knot protein.The simplicity and high efficiency of the strategy can be employed in the synthesis of artificial cyclotides for pharmaceutical applications.展开更多
The main purpose of this work is to distinguish various holographic type dark energy (DE) models, including the AHDE, HDE, NADE, and RDE model, by using various diagnostic tools. The first diagnostic tool is the Sta...The main purpose of this work is to distinguish various holographic type dark energy (DE) models, including the AHDE, HDE, NADE, and RDE model, by using various diagnostic tools. The first diagnostic tool is the Statefinder hierarchy, in which the evolution of Statefinder hierarchy parmeter S3(1)(z) and S4(1)(z) are studied. The second is composite null diagnostic (CND), in which the trajectories of {S(1)4, ∈} and {S4(1), e} are investigated, where ∈ is the fractional growth parameter. The last is w-w′ analysis, where w is the equation of state for DE and the prime denotes derivative with respect to lna. In the analysis we consider two cases: varying current fractional DE density Ωde0 and varying DE model parameter C. We find that: (1) both the Statefinder S4(1) can lead to larger hierarchy and the CND have qualitative impact on AHDE, but only have quantitative impact on HDE. (2) S4(1) differences than S 4(1), while the CND pair has a stronger ability to distinguish different models than the Statefinder hierarchy. (3) For the case of varying C, the {w, w′} pair has qualitative impact on AHDE; for the case of varying Ωde0, the {w, w′} pair only has quantitative impact; these results are different from the cases of HDE, RDE, and NADE, in which the {w, w′} pair only has quantitative impact on these models. In conclusion, compared with HDE, RDE, and NADE, the AHDE model can be easily distinguished by using these diagnostic tools.展开更多
The Sr3Tl5 phase was prepared by high temperature synthesis techniques through reaction of the high purity elements in the welded Nb tubes.The structure established through X-ray structural analysis shows the compound...The Sr3Tl5 phase was prepared by high temperature synthesis techniques through reaction of the high purity elements in the welded Nb tubes.The structure established through X-ray structural analysis shows the compound is a good hypoelectronic trielide example of the Pu3Pd5 structural type in which skeletal electron count is lower than in a traditional Zintl phase(Cmcm,Z = 4;a = 10.604(2) ,b = 8.675(2) ,and c = 10.985(2) ;V = 1010.5(3) 3).The strontium size and the compound's polarity appear responsible for this thallium phase crystallization in the Pu3Pd5 family type rather than the isoelectronic Sr3In5 version.A first-principle electronic structure calculation(LMTO) demonstrates that the strontium atoms participate substantially in Sr-Tl bonding in the structure.展开更多
Snake toxin Calciseptine as a natural antagonist of L-type calcium channel has potential drug values, but its structural information remains unknown. Here, we report the total chemical synthesis of Calciseptine by usi...Snake toxin Calciseptine as a natural antagonist of L-type calcium channel has potential drug values, but its structural information remains unknown. Here, we report the total chemical synthesis of Calciseptine by using hydrazide based native chemical ligation. The crystal structure of Calciseptine was determined by racemic protein crystallography technique. Compared to the structure of its homologous family protein, we found that Calciseptine is adopting a typical three-finger structure.展开更多
基金the Vice Chancellery of Research of IUMS for their financial support of the Research Project # 394774
文摘Over the past few years, the presence of steroid estrogens in the environment has become a major concern. In this study, the concentrations of estrone (El), 17β-estradinl (E2), and 17α-ethinyl estradiol (EE2) were measured in some wastewater treatment plants (WWTPs) in lran. These samples were collected from the municipal, rural, livestock, commercial, and hospital WWTPs, extracted by dispersive liquid-liquid micro extraction (DLLME) technique, derivatized, and detected by GC/MS. In these treatment plants, various processes including conven- tional activated sludge (CAS), aerated lagoon (AL), moving bed biofilm reactor (MBBR), and activated sludge with wetland (AS + WL) are used. The highest concentration of hormones was observed in the influents and effluents of livestock, municipal, commercial, and hospital WWTPs, respectively. The maximum elimination rate was obtained in MBBR followed by AS + WL CAS and AL The biodegradation and adsorption rates along with adsorption coefficients of 1g kd and 1g koc were measured for all target compounds.
文摘AIM: To identify the role of herbal compound 861 (Cpd 861) in the regulation of mRNA expression of collagen synthesis- and degradation-related genes in human hepatic stellate cells (HSCs). METHODS: mRNA levels of collagen types I and III, matrix metalloproteinase 1 (MMP-1), matrix metalloproteinase 2 (MMP-2), membrane type-1 matrix metalloproteinase (MT1-MMP), tissue inhibitor of metalloproteinase 1 (TIMP-1), and transforming growth factor β1 (TGF-β1) in cultured-activated HSCs treated with Cpd 861 or interferon-γ, (IFN-γ,) were determined by real-time PCR. RESULTS: Both Cpd 861 and IFN-γ reduced the mRNA levels of collagen type Ⅲ, MMP-2 and TGF-β1. Moreover, Cpd 861 significantly enhanced the MMP-1 mRNA levels while down-regulated the TIMP-1 mRNA expression, increasing the ratio of MMP-1 to TIMP-1 to (6.3 + 0.3)- fold compared to the control group. CONCLUSION: The anti-fibrosis function of Cpd 861 may be mediated by both decreased interstitial collagen sythesis by inhibiting the transcription of collagen type Ⅲ and TGF-β1 and increased degradation of these collagens by up-regulating MMP-1 and down-regulating TIMP-1 mRNA levels.
基金Supported by National Natural Science Foundation of China (No. 60872065)
文摘To extract region of interests (ROI) in brain magnetic resonance imaging (MRI) with more than two objects and improve the segmentation accuracy, a hybrid model of a kemel-based fuzzy c-means (KFCM) clustering algorithm and Chan-Vese (CV) model for brain MRI segmentation is proposed. The approach consists of two succes- sive stages. Firstly, the KFCM is used to make a coarse segmentation, which achieves the automatic selection of initial contour. Then an improved CV model is utilized to subdivide the image. Fuzzy membership degree from KFCM clus- tering is incorporated into the fidelity term of the 2-phase piecewise constant CV model to obtain accurate multi-object segmentation. Experimental results show that the proposed model has advantages both in accuracy and in robustness to noise in comparison with fuzzy c-means (FCM) clustering, KFCM, and the hybrid model of FCM and CV on brain MRI segmentation.
基金East Asia winter monsoon and Yunnan summertime drought and floods and their interdecadal anomalies a project of the Yunnan Province Science Foundation a Yunnan Province Foundation project (97D022G)
文摘Based on the data of NCEP, OLR and rainfall of China, we studied the influences of the East Asian winter monsoon activities on the precipitation during the raining season over China by correlation analysis and composite analysis. The result shows that annual and interdecadal change of East Asian winter monsoon is distinct. It is strong from 1950s to the middle of 1980s but weak after the middle of 1980s. The effect of abnormal winter monsoon on the precipitation during raining season is significant over the middle and lower reaches of the Changjiang River basin. It is revealed that the precipitation will increase when preceding winter monsoon is weak but decrease when preceding winter monsoon is strong. In this paper, some appropriate reasons are given to explain the abnormal rainfall by analyzing the distribution of SSTA and the variation of summer circulation. It is pointed out definitely that the variation of SSTA and summer circulation is a primary cause for abnormal rainfall over the middle and lower reaches of the Changjiang River.
文摘The composition of HMW-GS and pentosan and its various component contents in different wheat varieties were analyzed. According to scores of these subunits in several wheat varieties, the correlation relationship between the composition of HMW-GS, subunit combination types and pentosan, various components and component ratio were ascertained. The results showed that HMW-GSs were very diverse which had 11 types. In different varieties, the variation of Ara was obvious while Xyl was not; pentosan and its various component contents were very different, and their coefficient of variability was quite high. The majority of parameters had a significant negative correlation with Glu-1 where Glu-D1 was stronger than other two loci. N, 7, 17+18 and 2+12 subunits had influence on pentosan and its various component contents. But some subunits such as 1 and 5+ 10 which are good for baking quality had little contribution to pentosan and various component contents. The pentosan and various component contents were higher in the varieties which had (N, 7, 2+12) subunit combinations. Additionally, the 21 varieties were classified into 4 categories according to HMW-GS scores and pentosan content.
基金the National Natural Science Foundation of China (Grant No. 50075074).
文摘Type synthesis of lower-mobility parallel mechanisms is a hot and frontier topic in international academic and industrial field. Based on the Lie group theory, a displacement manifold synthesis method is proposed. For all the nine kinds of lower-mobility parallel mechanisms, the mechanism displacement manifold, limb displacement manifold and the geometrical conditions which guarantee that the intersection of the limb displacement manifold is the desired mechanism displacement manifold are enumerated. Various limb kinematic chains can be obtained using the product closure of displacement subgroup. Parallel mechanisms can be constructed with these limbs while obeying the geometrical conditions. Hence, all the nine kinds of lower-mobility parallel mechanisms can be synthesized using this method. Since displacement manifold deals with finite motion, the result mechanism of synthesis have full-cycle mobility. Novel architectures of lower-mobility parallel mechanisms can be obtained using this method.
基金supported by the National Natural Science Foundation of China(20932006,91013007)the National Basic Research Program of China(973 Program)(2011CB965300)
文摘Cyclotides constitute a fascinating family of circular proteins containing ca.30 amino acid residues.They have a unique cyclic cysteine knot topology and exhibit remarkable thermal,chemical and enzymatic stabilities.These characteristics enable them to have a range of biological activities and promising pharmaceutical and agricultural applications.Here,we present a practical strategy for the chemical synthesis of cyclotides through the intramolecular ligation of fully unprotected peptide O-esters.This strategy involves the mild Fmoc solid-phase peptide synthesis of the peptide O-ester backbone,the head-to-tail cyclization of the cyclotide backbone by native chemical ligation,and the oxidative refolding to yield the natural knot protein.The simplicity and high efficiency of the strategy can be employed in the synthesis of artificial cyclotides for pharmaceutical applications.
基金supported by the National Natural Science Foundation of China(Grant No.11405024)the Fundamental Research Funds for the Central Universities(Grant No.16lgpy50)
文摘The main purpose of this work is to distinguish various holographic type dark energy (DE) models, including the AHDE, HDE, NADE, and RDE model, by using various diagnostic tools. The first diagnostic tool is the Statefinder hierarchy, in which the evolution of Statefinder hierarchy parmeter S3(1)(z) and S4(1)(z) are studied. The second is composite null diagnostic (CND), in which the trajectories of {S(1)4, ∈} and {S4(1), e} are investigated, where ∈ is the fractional growth parameter. The last is w-w′ analysis, where w is the equation of state for DE and the prime denotes derivative with respect to lna. In the analysis we consider two cases: varying current fractional DE density Ωde0 and varying DE model parameter C. We find that: (1) both the Statefinder S4(1) can lead to larger hierarchy and the CND have qualitative impact on AHDE, but only have quantitative impact on HDE. (2) S4(1) differences than S 4(1), while the CND pair has a stronger ability to distinguish different models than the Statefinder hierarchy. (3) For the case of varying C, the {w, w′} pair has qualitative impact on AHDE; for the case of varying Ωde0, the {w, w′} pair only has quantitative impact; these results are different from the cases of HDE, RDE, and NADE, in which the {w, w′} pair only has quantitative impact on these models. In conclusion, compared with HDE, RDE, and NADE, the AHDE model can be easily distinguished by using these diagnostic tools.
基金supporting (by his DOE grant DE-AC02-07CH11358) the visit of J. C. Dai to Ames Laboratory, where principal part of this research was carried outthe National Natural Science Foundation of China (50971063)+1 种基金the Natural Science Foundation of Fujian Province of China (2010J01042 & 2011J01047)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of China for supporting
文摘The Sr3Tl5 phase was prepared by high temperature synthesis techniques through reaction of the high purity elements in the welded Nb tubes.The structure established through X-ray structural analysis shows the compound is a good hypoelectronic trielide example of the Pu3Pd5 structural type in which skeletal electron count is lower than in a traditional Zintl phase(Cmcm,Z = 4;a = 10.604(2) ,b = 8.675(2) ,and c = 10.985(2) ;V = 1010.5(3) 3).The strontium size and the compound's polarity appear responsible for this thallium phase crystallization in the Pu3Pd5 family type rather than the isoelectronic Sr3In5 version.A first-principle electronic structure calculation(LMTO) demonstrates that the strontium atoms participate substantially in Sr-Tl bonding in the structure.
基金supported by the National Natural Science Foundation of China (21572043, 21473176)the Ministry of Science and Technology (2016YFA0400900, 2015CB910103)the Fundamental Research Funds for the Central Universities (PA2017GDQT0021)
文摘Snake toxin Calciseptine as a natural antagonist of L-type calcium channel has potential drug values, but its structural information remains unknown. Here, we report the total chemical synthesis of Calciseptine by using hydrazide based native chemical ligation. The crystal structure of Calciseptine was determined by racemic protein crystallography technique. Compared to the structure of its homologous family protein, we found that Calciseptine is adopting a typical three-finger structure.