The method of regularization factor selection determines stability and accuracy of the regularization method. A formula of regularization factor was proposed by analyzing the relationship between the improved SVD and ...The method of regularization factor selection determines stability and accuracy of the regularization method. A formula of regularization factor was proposed by analyzing the relationship between the improved SVD and regularization method. The improved SVD algorithm and regularization method could adapt to low SNR. The regularization method is better than the improved SVD in the case that SNR is below 30 and the improved SVD is better than the regularization method when SNR is higher than 30. The regularization method with the regularization factor proposed in this paper can be better applied into low SNR （5〈SNR） NMR logging. The numerical simulations and real NMR data process results indicated that the improved SVD algorithm and regularization method could adapt to the low signal to noise ratio and reduce the amount of computation greatly. These algorithms can be applied in NMR logging.展开更多
Pregnane and Xenobiotic Receptor (PXR; or Steroid and Xenobiotic Receptor, SXR), a new member of the nuclear receptor superfamily, is thought to modulate a network of genes that are involved in xenobiotic metabolism a...Pregnane and Xenobiotic Receptor (PXR; or Steroid and Xenobiotic Receptor, SXR), a new member of the nuclear receptor superfamily, is thought to modulate a network of genes that are involved in xenobiotic metabolism and elimination. To further explore the role of PXR in body’s homeostatic mechanisms, we for the first time, report successful prokary- otic expression and purification of full-length PXR and preparation of polyclonal antibody against the whole protein. The full-length cDNA encoding a 434 amino acids protein was sub-cloned into prokaryotic expression vector, pET-30b and transformed into E. coli BL21(DE3) cells for efficient over expression. The inclusion body fraction, containing the expressed recombinant protein, was purified first by solubilizing in sarcosine extraction buffer and then by affinity column chromatography using Ni-NTA His-Bind matrix. The efficacy of anti-PXR antibody was confirmed by immunocytology, Western blot analysis, EMSA and immunohistochemistry. The antibody obtained was capable of detecting human and mouse PXR with high specificity and sensitivity. Immunofluorescence staining of COS-1 cells transfected with human or mouse PXR showed a clear nuclear localization. Results from immunohistochemistry showed that level of PXR in liver sections is immunologically detectable in the nuclei. Similar to exogenously transfected PXR, Western blot analysis of cell extract from HepG2 and COLO320DM cells revealed a major protein band for endogenous PXR having the expected molecular weight of 50 kDa. Relevance of other immunodetectable bands with reference to PXR isoforms and current testimony are evaluated. Advantages of antibody raised against full-length PXR protein for functional characterization of receptor is discussed and its application for clinical purposes is envisaged.展开更多
Polyketides have been widely used clinically due to their significant biological activities, but the needed structural and functional diversity cannot be achieved by common chemical synthetic methods. The tool of comb...Polyketides have been widely used clinically due to their significant biological activities, but the needed structural and functional diversity cannot be achieved by common chemical synthetic methods. The tool of combinatorial biosynthesis provides the possibility to produce "unnatural" natural drugs, which has achieved initial success. This paper provides an overview for the strategies of combinatorial biosynthesis in producing the structural and functional diversity of polyketides, including the redesign of metabolic flow, polyketide synthase(PKS) engineering, and PKS post-translational modification. Although encouraging progress has been made in the last decade, challenges still exist regarding the rational combinatorial biosynthesis of polyketides. In this review, the perspectives of polyketide combinatorial biosynthesis are also discussed.展开更多
Language and culture are closely related to each other. Euphemisms, which exist in all languages, reflect certain culture from which the language derives. Paying special attention to cross cultural communication, this...Language and culture are closely related to each other. Euphemisms, which exist in all languages, reflect certain culture from which the language derives. Paying special attention to cross cultural communication, this paper discusses the relationship between euphemism and culture. Pointing out the necessity of learning and teaching euphemisms, the author also proposes some suggestions on how to teach euphemism.展开更多
The study is based on an observation of the pronunciation of a group of undergraduate students of English as a Second Language （ESL） whose mother tongue is Arabic and who have no formal training in the spoken variet...The study is based on an observation of the pronunciation of a group of undergraduate students of English as a Second Language （ESL） whose mother tongue is Arabic and who have no formal training in the spoken variety of English other than that received in the classroom. The study of acquisition of pronunciation of consonant clusters at morphological, particularly at the morphophonological levels indicates that the learners are sensitive to the syllabic structure viz., cccv type and cccvcc type, at the word-initial, medial and final positions. Samples of words with different consonant clusters were tested with a homogeneous group of students. Words of identical morphological categories were used as the data to test the students＇ level of perception. These were analyzed using Speech Analyzer Version 2.5. The data includes consonant clusters like plosive-fricative, plosive-plosive, fricative-fricative and plosive-fricative-trill/liquid combinations. The results varied according to the perceptual and articulatory abilities of the learners. It was observed that the plosive perception and acquisition of three-consonant clusters of plosive-plosive word initially, plosive-plosive combinations word finally and plosive-fricative type, posed more difficulty for the learners. The tendency to drop one of the consonants of the cluster was more pronounced with syllables ending in plural morphemes and those ending in -mp, -pt, -kt, -nt, -bt, etc. Difficulty was also noticed with the initial plosive＋/r/, plosive＋/1/combinations, especially in word initial positions. Across the syllable boundaries, these clusters are almost inaudible with some speakers. The difficulty in the articulation of these consonant clusters can be accounted for the mother tongue influence, as in the case of many other features. The results of the analysis have a pedagogical implication in the use of such words with consonant clusters, to teach reading skills to the students of undergraduate level in the present setting and promote self-learning through the use of speech tools.展开更多
Language and culture are interactive and interdependent. Translation is not only the transfer between two languages, but also between two cultures. Therefore, cultural difference plays a significant role in translatio...Language and culture are interactive and interdependent. Translation is not only the transfer between two languages, but also between two cultures. Therefore, cultural difference plays a significant role in translation. In the past decades, translation study has shifted from the purely linguistic level to cultural perspective, and study on cultural differences has brought a new world for the sake of translation studies. This paper tries to illustrate the connection between language and culture, the correlation between culture and translation, analyze the main aspects of cultural differences between Chinese and Western, and sum up translation strategies of domestication and foreignization as well as specific translation methods on the consideration of cultural differences. Finally, the paper proposes that translators should pay attention to cultural differences and adjust target text in accordance with cultural differences展开更多
文摘The method of regularization factor selection determines stability and accuracy of the regularization method. A formula of regularization factor was proposed by analyzing the relationship between the improved SVD and regularization method. The improved SVD algorithm and regularization method could adapt to low SNR. The regularization method is better than the improved SVD in the case that SNR is below 30 and the improved SVD is better than the regularization method when SNR is higher than 30. The regularization method with the regularization factor proposed in this paper can be better applied into low SNR （5〈SNR） NMR logging. The numerical simulations and real NMR data process results indicated that the improved SVD algorithm and regularization method could adapt to the low signal to noise ratio and reduce the amount of computation greatly. These algorithms can be applied in NMR logging.
文摘Pregnane and Xenobiotic Receptor (PXR; or Steroid and Xenobiotic Receptor, SXR), a new member of the nuclear receptor superfamily, is thought to modulate a network of genes that are involved in xenobiotic metabolism and elimination. To further explore the role of PXR in body’s homeostatic mechanisms, we for the first time, report successful prokary- otic expression and purification of full-length PXR and preparation of polyclonal antibody against the whole protein. The full-length cDNA encoding a 434 amino acids protein was sub-cloned into prokaryotic expression vector, pET-30b and transformed into E. coli BL21(DE3) cells for efficient over expression. The inclusion body fraction, containing the expressed recombinant protein, was purified first by solubilizing in sarcosine extraction buffer and then by affinity column chromatography using Ni-NTA His-Bind matrix. The efficacy of anti-PXR antibody was confirmed by immunocytology, Western blot analysis, EMSA and immunohistochemistry. The antibody obtained was capable of detecting human and mouse PXR with high specificity and sensitivity. Immunofluorescence staining of COS-1 cells transfected with human or mouse PXR showed a clear nuclear localization. Results from immunohistochemistry showed that level of PXR in liver sections is immunologically detectable in the nuclei. Similar to exogenously transfected PXR, Western blot analysis of cell extract from HepG2 and COLO320DM cells revealed a major protein band for endogenous PXR having the expected molecular weight of 50 kDa. Relevance of other immunodetectable bands with reference to PXR isoforms and current testimony are evaluated. Advantages of antibody raised against full-length PXR protein for functional characterization of receptor is discussed and its application for clinical purposes is envisaged.
基金supported by the Major Research Plan of Tianjin(No.16YFXTSF00460)
文摘Polyketides have been widely used clinically due to their significant biological activities, but the needed structural and functional diversity cannot be achieved by common chemical synthetic methods. The tool of combinatorial biosynthesis provides the possibility to produce "unnatural" natural drugs, which has achieved initial success. This paper provides an overview for the strategies of combinatorial biosynthesis in producing the structural and functional diversity of polyketides, including the redesign of metabolic flow, polyketide synthase(PKS) engineering, and PKS post-translational modification. Although encouraging progress has been made in the last decade, challenges still exist regarding the rational combinatorial biosynthesis of polyketides. In this review, the perspectives of polyketide combinatorial biosynthesis are also discussed.
文摘Language and culture are closely related to each other. Euphemisms, which exist in all languages, reflect certain culture from which the language derives. Paying special attention to cross cultural communication, this paper discusses the relationship between euphemism and culture. Pointing out the necessity of learning and teaching euphemisms, the author also proposes some suggestions on how to teach euphemism.
文摘The study is based on an observation of the pronunciation of a group of undergraduate students of English as a Second Language （ESL） whose mother tongue is Arabic and who have no formal training in the spoken variety of English other than that received in the classroom. The study of acquisition of pronunciation of consonant clusters at morphological, particularly at the morphophonological levels indicates that the learners are sensitive to the syllabic structure viz., cccv type and cccvcc type, at the word-initial, medial and final positions. Samples of words with different consonant clusters were tested with a homogeneous group of students. Words of identical morphological categories were used as the data to test the students＇ level of perception. These were analyzed using Speech Analyzer Version 2.5. The data includes consonant clusters like plosive-fricative, plosive-plosive, fricative-fricative and plosive-fricative-trill/liquid combinations. The results varied according to the perceptual and articulatory abilities of the learners. It was observed that the plosive perception and acquisition of three-consonant clusters of plosive-plosive word initially, plosive-plosive combinations word finally and plosive-fricative type, posed more difficulty for the learners. The tendency to drop one of the consonants of the cluster was more pronounced with syllables ending in plural morphemes and those ending in -mp, -pt, -kt, -nt, -bt, etc. Difficulty was also noticed with the initial plosive＋/r/, plosive＋/1/combinations, especially in word initial positions. Across the syllable boundaries, these clusters are almost inaudible with some speakers. The difficulty in the articulation of these consonant clusters can be accounted for the mother tongue influence, as in the case of many other features. The results of the analysis have a pedagogical implication in the use of such words with consonant clusters, to teach reading skills to the students of undergraduate level in the present setting and promote self-learning through the use of speech tools.
文摘Language and culture are interactive and interdependent. Translation is not only the transfer between two languages, but also between two cultures. Therefore, cultural difference plays a significant role in translation. In the past decades, translation study has shifted from the purely linguistic level to cultural perspective, and study on cultural differences has brought a new world for the sake of translation studies. This paper tries to illustrate the connection between language and culture, the correlation between culture and translation, analyze the main aspects of cultural differences between Chinese and Western, and sum up translation strategies of domestication and foreignization as well as specific translation methods on the consideration of cultural differences. Finally, the paper proposes that translators should pay attention to cultural differences and adjust target text in accordance with cultural differences
