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Kong F, Zhou J, Du C, He X, Kong L, Hu C, Ying H. Long-Term Survival and Late Complications of Intensity-Modulated Radiation Therapy for Recurrent Nasopharyngeal Carcinoma. Int J Radiat Oncol Biol Phys 2018. [DOI: 10.1016/j.ijrobp.2018.07.929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zeng J, Ke J, Li LJ, Du C, Hu WN, Wang L. [Laryngeal NK/T cell lymphoma mainly manifested as sore throat, hoarseness, fever: a case report]. ZHONGHUA ER BI YAN HOU TOU JING WAI KE ZA ZHI = CHINESE JOURNAL OF OTORHINOLARYNGOLOGY HEAD AND NECK SURGERY 2018; 53:448-449. [PMID: 29902851 DOI: 10.3760/cma.j.issn.1673-0860.2018.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Li LJ, Wang L, Du C, Yan Y, Zeng J. [Application of endoscope assisted curved laryngoscope in laryngeal microsurgery of patients with difficulty laryngeal exposure]. LIN CHUANG ER BI YAN HOU TOU JING WAI KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY, HEAD, AND NECK SURGERY 2018; 32:282-284. [PMID: 29798505 DOI: 10.13201/j.issn.1001-1781.2018.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Indexed: 11/12/2022]
Abstract
Objective:To investigate the feasibility and clinical value of endoscope assisted curved laryngoscopy in laryngeal microsurgery of patients with difficulty laryngeal exposure. Method:The data of 28 patients with difficulty laryngeal exposure underwent microlaryngosurgery with endoscope assisted curved laryngoscopy technique were collected. Result:Surgeries with endoscope assisted curved laryngoscopy technique were completed successfully one-time in all patients. The fully exposure of glottis was 100%. All cases were followed up for 2 to 18 months. No residual disease or recurrence occurred and no obvious complication occurred. Conclusion:Endoscope assisted curved laryngoscopy technique is a useful solution to difficulty laryngeal exposure. It has satisfactory glottis exposure, clear surgical field and fewer complications which is worthy of promotion.
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Zhang M, Zhu X, Xu X, Jin X, Bao H, Dugeer S, Du C, Cao G, Yang Y. Molecular characterization and expression patterns of ghrelin in the reindeer (Rangifer tarandus). Pol J Vet Sci 2018; 21:55-64. [PMID: 29624010 DOI: 10.24425/119022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Ghrelin is a novel growth hormone (GH)-releasing peptide, which has been identified as an endogenous ligand for the GH-sretagogue receptor. The sequence and expression of ghrelin has been determined in many species. In this study, to reveal the molecular characterization and expression patterns of ghrelin in the reindeer (Rangifer tarandus), the full-length DNA and cDNA encoding ghrelin were cloned from reindeer stomach using genome walking and rapid amplification of complementary deoxyribonucleic acid ends (RACE). The expression of ghrelin in almost all tissues was examined by real-time quantitative PCR (RT-qPCR). The 4076 bp amplicon of the ghrelin gene consisting of 4 exons and 3 introns was cloned from reindeer. Results of cDNA cloning and sequence analysis revealed that the full-length ghrelin cDNA was composed of 539 bp that included a 5'-untranslated region (46 bp), an open reading frame (ORF) (351 bp), and a 3'-untranslated region (142 bp). In addition, ghrelin was expressed in the all tissues examined, with the expression in the abomasum significantly higher than that in other tissues (p<0.05), followed by the pancreas, duodenum, testis and oesophagus. The results show that the expression of ghrelin in the reindeer gastrointestinal tract is extensive, suggesting its may have a role in regulating the digestive function.
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Meng HX, Li HN, Song HT, Li HY, Du C, Shi QT, Geng JS. [Clinicopathologic analysis and classification of 2 093 cases of lymphomas: experiences in Heilongjiang Province of China]. ZHONGHUA BING LI XUE ZA ZHI = CHINESE JOURNAL OF PATHOLOGY 2018; 47:57-58. [PMID: 29325252 DOI: 10.3760/cma.j.issn.0529-5807.2018.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
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Li LJ, Du C, Wang L, Yan Y, Zeng J, Xu CY, Sun SL. [Application of endoscope assisted curved laryngoscopy technique in transoral laryngopharyngeal minimally invasive surgery]. ZHONGHUA ER BI YAN HOU TOU JING WAI KE ZA ZHI = CHINESE JOURNAL OF OTORHINOLARYNGOLOGY HEAD AND NECK SURGERY 2018; 53:45-48. [PMID: 29365380 DOI: 10.3760/cma.j.issn.1673-0860.2018.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To explore the possibility of endoscope assisted curved laryngoscopy technique applied in transoral laryngopharyngeal minimally invasive surgery and evaluate the advantages of this technique. Methods: Eight patients with huge benign lesions in larynx and pharynx undergoing transoral microsurgery at Peking University Third Hospital between February 2016 and February 2017 were enrolled in this study.The diagnosis included cyst at the base of tongue in two patients, cysts in the epiglottis in two patients, hemangioma in two patients, multiple masses of the hypopharynx and amyloidosis in supraglottic area in one patient each.The time and exposure during surgery, occurrence rate of complication and conditions of following-up were recorded. Results: The mean time of surgery was 20 min, the exposure was satisfying.There was no obvious complication after surgery.No residual or recurrent lesion was observed after 1 to 12 months follow-up(mean time 4.5 months). Conclusion: The endoscope assisted curved laryngoscopy technique has advantages in shortening the time of surgery, improving exposure and reducing the rate of complication and recurrence.
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Zhou Z, Menzel F, Benninghoff T, Chadt A, Du C, Holman GD, Al-Hasani H. Rab28 ist ein neu beschriebenes Substrat für TBC1D1/TBC1D4 und beteiligt an der regulierten Translokation von GLUT4. DIABETOL STOFFWECHS 2017. [DOI: 10.1055/s-0037-1601642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Wen ZP, Fan SS, Du C, Yin T, Zhou BT, Peng ZF, Xie YY, Zhang W, Chen Y, Xiao J, Chen XP. Drug-drug interaction between valproic acid and meropenem: a retrospective analysis of electronic medical records from neurosurgery inpatients. J Clin Pharm Ther 2017; 42:221-227. [PMID: 28145574 DOI: 10.1111/jcpt.12501] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 12/09/2016] [Indexed: 11/29/2022]
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Du C, Xu Y, Yang K, Chen S, Wang X, Wang S, Wang C, Shen M, Chen F, Chen M, Zeng D, Li F, Wang T, Wang F, Zhao J, Ai G, Cheng T, Su Y, Wang J. Estrogen promotes megakaryocyte polyploidization via estrogen receptor beta-mediated transcription of GATA1. Leukemia 2016; 31:945-956. [DOI: 10.1038/leu.2016.285] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 09/13/2016] [Accepted: 09/14/2016] [Indexed: 12/21/2022]
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Kong F, Ying H, Zhai R, Du C, Huang S, Zhou J, He X, Zhu G, Shen C, Hu C. Clinical Outcome of Intensity Modulated Radiation Therapy for Carcinoma Showing Thymus-like Differentiation. Int J Radiat Oncol Biol Phys 2016. [DOI: 10.1016/j.ijrobp.2016.06.1539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Claus J, Du C, Kılıç B. Inhibition of lipid oxidation in ground turkey breasts by encapsulated Polyphosphates as influenced by postmortem pH. Meat Sci 2016. [DOI: 10.1016/j.meatsci.2015.08.067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Shen Z, Du C, Zang R, Xie H, Lv W, Li H, Xia Y, Tang W. Microarray expression profiling of dysregulated long non-coding RNAs in Hirschsprung's disease reveals their potential role in molecular diagnosis. Neurogastroenterol Motil 2016; 28:266-73. [PMID: 26574899 DOI: 10.1111/nmo.12722] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 10/07/2015] [Indexed: 02/08/2023]
Abstract
BACKGROUND Hirschsprung's disease (HSCR) is one of the common digestive disorders in the new born. Long non-coding RNAs (lncRNAs) play an important role in various biological processes. However, knowledge on lncRNAs in HSCR is limited. METHODS The expression profile of lncRNAs in HSCR was obtained using microarray. A total of 2078 differentially expressed lncRNAs were detected by microarray in HSCR tissues compared with matched normal colon tissues (fold change ≥2, p < 0.05). Candidate biomarkers were selected from these differentially expressed lncRNAs based on artificial criterion (raw signal intensity ≥50; fold change ≥8) and then validated in 80 pairs of HSCR and normal tissues using quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, the computational analysis was used to evaluate the lncRNA-microRNA and lncRNA-protein relationships. KEY RESULTS A panel of 5-lncRNAs was identified to distinguish HSCR from normal tissues with remarkable sensitivity and specificity. The area under the receiver operating characteristic curve (AUC) for HSCR identification in the validation set was 0.875. The bioinformatics analysis reveals that these dysregulated lncRNAs are mainly involved in RNA-protein relationships, including RNA splicing, binding, transport, processing, and localization. CONCLUSIONS & INFERENCES Our results are the first to report the expression profile of dysregulated lncRNAs in HSCR and infer that lncRNAs may serve as novel diagnostic biomarkers for HSCR.
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Xiao J, Qiu Z, He W, Du C, Zhou W. Progress in Platinum Catalysts Supported by Inorganic Carriers for Hydrosilylation. CHINESE J ORG CHEM 2016. [DOI: 10.6023/cjoc201509028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Zou D, Liu T, Du C, Teng J. Influence of Wind Pressure on the Carbonation of Concrete. MATERIALS 2015; 8:4652-4667. [PMID: 28793462 PMCID: PMC5455509 DOI: 10.3390/ma8084652] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/07/2015] [Accepted: 07/20/2015] [Indexed: 11/16/2022]
Abstract
Carbonation is one of the major deteriorations that accelerate steel corrosion in reinforced concrete structures. Many mathematical/numerical models of the carbonation process, primarily diffusion-reaction models, have been established to predict the carbonation depth. However, the mass transfer of carbon dioxide in porous concrete includes molecular diffusion and convection mass transfer. In particular, the convection mass transfer induced by pressure difference is called penetration mass transfer. This paper presents the influence of penetration mass transfer on the carbonation. A penetration-reaction carbonation model was constructed and validated by accelerated test results under high pressure. Then the characteristics of wind pressure on the carbonation were investigated through finite element analysis considering steady and fluctuating wind flows. The results indicate that the wind pressure on the surface of concrete buildings results in deeper carbonation depth than that just considering the diffusion of carbon dioxide. In addition, the influence of wind pressure on carbonation tends to increase significantly with carbonation depth.
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Du C, Claus J. Inhibition of lipid oxidation in ground turkey with encapsulated phosphates as affected by meat age, phosphate type, and temperature release point. Meat Sci 2015. [DOI: 10.1016/j.meatsci.2014.09.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Li W, Du C, Wang H, Zhang C. Increased serum ADAMTS-4 in knee osteoarthritis: a potential indicator for the diagnosis of osteoarthritis in early stages. GENETICS AND MOLECULAR RESEARCH 2014; 13:9642-9. [PMID: 25501175 DOI: 10.4238/2014.november.14.9] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We compared serum levels of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, ADAMTS-5, matrix metalloproteinase (MMP)-1, and MMP-3 in patients with different stages of knee osteoarthritis (OA), and investigated the clinical significance of diagnosing OA in early stages. OA patients were divided into 2 groups: early OA group (44 cases), intermediate and advanced OA group (26 cases). The healthy control group included 30 samples. ADAMTS-4, ADAMTS-5, MMP-1, and MMP-3 levels in the serum were tested using an enzyme-linked immunosorbent assay. A protein-protein interaction network was constructed by seeding the significantly expressed marker, followed by Gene Ontology enrichment analyses using Database for Annotation, Visualization and Integrated Discovery. ADAMTS-4 levels were significantly higher in patients at early stages of OA compared to intermediate or advanced OA and healthy controls. ADAMTS-5, MMP-1, and MMP-3 levels in intermediate and advanced-stage OA patients were significantly higher than those in early-stage OA patients and healthy controls. The protein-protein interaction network showed that ADAMTS-4 participates in 67 interactions. Gene Ontology enrichment analysis validated that genes associated with ADAMTS-4 participate in collagen metabolism and OA. ADAMTS-4 is a potential biomarker as an early diagnostic indicator of OA.
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Volkow ND, Tomasi D, Wang GJ, Logan J, Alexoff DL, Jayne M, Fowler JS, Wong C, Yin P, Du C. Stimulant-induced dopamine increases are markedly blunted in active cocaine abusers. Mol Psychiatry 2014; 19:1037-43. [PMID: 24912491 PMCID: PMC4827430 DOI: 10.1038/mp.2014.58] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/27/2014] [Accepted: 04/29/2014] [Indexed: 12/18/2022]
Abstract
Dopamine signaling in nucleus accumbens is essential for cocaine reward. Interestingly, imaging studies have reported blunted dopamine increases in striatum (assessed as reduced binding of [(11)C]raclopride to D2/D3 receptors) in detoxified cocaine abusers. Here, we evaluate whether the blunted dopamine response reflected the effects of detoxification and the lack of cocaine-cues during stimulant exposure. For this purpose we studied 62 participants (43 non-detoxified cocaine abusers and 19 controls) using positron emission tomography and [(11)C]raclopride (radioligand sensitive to endogenous dopamine) to measure dopamine increases induced by intravenous methylphenidate and in 24 of the cocaine abusers, we also compared dopamine increases when methylphenidate was administered concomitantly with a cocaine cue-video versus a neutral-video. In controls, methylphenidate increased dopamine in dorsal (effect size 1.4; P<0.001) and ventral striatum (location of accumbens) (effect size 0.89; P<0.001), but in cocaine abusers methylphenidate's effects did not differ from placebo and were similar whether cocaine-cues were present or not. In cocaine abusers despite the markedly attenuated dopaminergic effects, the methylphenidate-induced changes in ventral striatum were associated with intense drug craving. Our findings are consistent with markedly reduced signaling through D2 receptors during intoxication in active cocaine abusers regardless of cues exposure, which might contribute to compulsive drug use.
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Xu G, Fu X, Du C, Ma J, Li Z, Ma X. Biomechanical effects of vertebroplasty on thoracolumbar burst fracture with transpedicular fixation: a finite element model analysis. Orthop Traumatol Surg Res 2014; 100:379-83. [PMID: 24835003 DOI: 10.1016/j.otsr.2014.03.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 12/17/2013] [Accepted: 03/13/2014] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate the biomechanical effects of augmentation of the fractured vertebrae after posterior instrumentation. METHODS By simulating internal fixation plus augmentation with cement, eight tridimensional, anatomically detailed finite element models of the T11-L1 functional spinal junction were developed. Two kinds of models for mimicking different severity of the fracture were established according to the Denis' classification. Augmentation with cement was conducted after reduction with posterior fixation using a universal spine system. These models assumed a three-column loading configuration as follows: compression, anteflexion, extension, lateroflexion and axial rotation. Stress of the implants and spine was evaluated. RESULTS Data showed that for severely fractured models, augmentation apparently decreased the von Mises stresses by 50% for the rods and 40% for the screws, about 40% for the inferior endplate of T11, and 50% for the superior endplate of L1 in vertical compression and other load situations. CONCLUSION We should only apply vertebroplasty to prevent correction loss and implants failure based on the fact that it could significantly decrease stress of the instrumentations and spine when the vertebrae are severely fractured. LEVEL OF EVIDENCE Level IV, biomechanical study.
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Ke Y, Liu GS, Wang JH, Xue W, Du C, Wu G. Preparation of carboxymethyl cellulose based microgels for cell encapsulation. EXPRESS POLYM LETT 2014. [DOI: 10.3144/expresspolymlett.2014.85] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Rios-Solis L, Bayir N, Halim M, Du C, Ward J, Baganz F, Lye G. Non-linear kinetic modelling of reversible bioconversions: Application to the transaminase catalyzed synthesis of chiral amino-alcohols. Biochem Eng J 2013. [DOI: 10.1016/j.bej.2013.01.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Poppelreuther M, Küch EM, Grossmann R, Du C, Ehehalt F, Staudacher S, Ehehalt R, Füllekrug J. Acyl-CoA synthetases in lipid metabolism and storage. Exp Clin Endocrinol Diabetes 2012. [DOI: 10.1055/s-0032-1330800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Du C, Lee SH, Huang CL, Lai YC, Wu PF, Chou FC. Study of charge stripes and charge density waves using X-ray scattering. Acta Crystallogr A 2011. [DOI: 10.1107/s010876731108531x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Cheng Y, Wang L, Ma F, Du C. Dynamic changes of the ecological environment quality in a river basin: a case study of the main stream of Songhua river basin. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2011; 64:1920-1925. [PMID: 22020488 DOI: 10.2166/wst.2011.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper reports the investigation and analysis of the status and dynamic changes of ecological environment quality in the main stream of Songhua river basin. The evaluation index system was established and the eco-environment quality in the year of 2000 and 2008 was studied in depth. Based on our research, the trend of dynamic changes of the eco-environment quality and its origins have been further discussed: In the year of 2000, the range of evaluation index covered from 0.31 to 0.47. Harbin and Yichun was relatively better than the rest of study areas. In the year of 2008, except districts of Daqing and Qitaihe, the environmental quality of Songhua river basin has entirely improved, wherein the evaluation index of the eco-environment covered from 0.31 to 0.57. Particularly, the eco-environment quality of Hegang and Shuangyashan has obtained significant improvement, whereas the improvement of Jiamusi was not obvious. According to the evaluation results, the environmental quality in the study area has an upward trend with the average growth rate 0.13% per year.
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Polson AG, Williams M, Gray AM, Fuji RN, Poon KA, McBride J, Raab H, Januario T, Go M, Lau J, Yu SF, Du C, Fuh F, Tan C, Wu Y, Liang WC, Prabhu S, Stephan JP, Hongo JA, Dere RC, Deng R, Cullen M, de Tute R, Bennett F, Rawstron A, Jack A, Ebens A. Anti-CD22-MCC-DM1: an antibody-drug conjugate with a stable linker for the treatment of non-Hodgkin's lymphoma. Leukemia 2010; 24:1566-73. [DOI: 10.1038/leu.2010.141] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Du C, Martin PA, Nickerson KW. Comparison of Disulfide Contents and Solubility at Alkaline pH of Insecticidal and Noninsecticidal Bacillus thuringiensis Protein Crystals. Appl Environ Microbiol 2010; 60:3847-53. [PMID: 16349421 PMCID: PMC201894 DOI: 10.1128/aem.60.10.3847-3853.1994] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared two insecticidal and eight noninsecticidal soil isolates of Bacillus thuringiensis with regard to the solubility of their proteinaceous crystals at alkaline pH values. The protein disulfide contents of the insecticidal and noninsecticidal crystals were equivalent. However, six of the noninsecticidal crystals were soluble only at pH values of >/=12. This lack of solubility contributed to their lack of toxicity. One crystal type which was soluble only at pH >/=12 (strain SHP 1-12) did exhibit significant toxicity to tobacco hornworm larvae when the crystals were presolubilized. In contrast, freshly prepared crystals from the highly insecticidal strain HD-1 were solubilized at pH 9.5 to 10.5, but when these crystals were denatured, by either 8 M urea or autoclave temperatures, they became nontoxic and were soluble only at pH values of >/=12. These changes in toxicity and solubility occurred even though the denatured HD-1 crystals were morphologically indistinguishable from native crystals. Our data are consistent with the view that insecticidal crystals contain distorted, destabilized disulfide bonds which allow them to be solubilized at pH values (9.5 to 10.5) characteristic of lepidopteran and dipteran larval midguts.
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