The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in fabrication.An isotropic synthetic pitch was prepared by a chlor...The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in fabrication.An isotropic synthetic pitch was prepared by a chlorine-and/or nitrogen-induced sub-stitution polymerization reaction method using aromatic hydrocarbon precursors containing Cl and N,which for this study were chloromethyl naphthalene and quinoline.This method was verified by investigating the structural changes under different synthesis conditions,and the synthesis mechanism induced by aromatics containing Cl was also probed.The result shows that the pyridinic N in quinoline contains a lone pair of electrons,and is an effective active site to induce the polymerization reaction by coupling with aromatic hydrocarbons containing Cl.The reaction between such free radicals causes strong homopolymerization and oligomeriza-tion.A higher reaction temperature and longer reaction time significantly increased the degree of polymerization and thus increased the softening point of the pitch.A linear molecular structure was formed by the Cl substitution reaction,which produced a highly spinnable pitch with a softening point of 258.6℃,and carbon fibers with a tensile strength of 1163.82 MPa were obtained.This study provides a relatively simple and safe method for the preparation of high-quality spinnable pitch.展开更多
The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particle...The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particles was smiliar to that of kaolinite clay. On the surface of BS, both toluene insoluble organic matter and structural OH group are detected at the same time. The surface characteristics imparted a bi-wettable nature to the BS. As a result, the BS is able to stabilize fine water emulsion in the bitumen phase. The organic matter associated with BS is a possible factor of the fouling on catalyst and equipment.展开更多
In this paper, studies were carried out to extract astaxanthin from discharged wastewater during the production of chitin and to reveal the scavenging effect of the obtained pigment on 1, 1-diphenyl-2-picrylhydrazyl (...In this paper, studies were carried out to extract astaxanthin from discharged wastewater during the production of chitin and to reveal the scavenging effect of the obtained pigment on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. Different ratios of dichloromethane/methanol (V/V) were used to extract astaxanthin. When the ratio of dichloromethane/methanol was 2:8 and the ratio between the mixed organic solvent (dichloromethane/methanol, 2:8, V/V) and wastewater was 1:1, the highest yield of pigment was obtained (8.4 mg/ 50 mL). The concentration of free astaxanthin in the obtained pigment analyzed by HPLC was 30.02%. The obtained pigment possessed strong scavenging ability on DPPH radical and IC50 was 0.84mg/ml.展开更多
The purpose of this subject was to investigate molecular epidemiology of oxacillin-resistant Staphylococcus aureus (MRSA) isolated from hospitalized patients, and to survey the in vitro activity of teicoplanin, vancom...The purpose of this subject was to investigate molecular epidemiology of oxacillin-resistant Staphylococcus aureus (MRSA) isolated from hospitalized patients, and to survey the in vitro activity of teicoplanin, vancomycin and other 9 antibiotics against Staphylococcus species . MRSA were detected by oxacillin-NaCl-containing screen agar. The homology of nosocomial MRSA from ICU and RCU was determined by pulse-field gel electrophoresis. Agar diffusion, E test and agar dilution were used to compare the in vitro activity of teicoplanin and vancomycin against Staphylococcus spp from 2001 to 2003 at Peking Union Medical College Hospital. WHONET-5.3 software was used to analyze the antimicrobial susceptibility data. From 2001 to 2003, the prevalences of MRSA were 56.5%, 65.3%, 64.7%, respectively. PFGE found most of MRSA from ICU and RCU were closely related. All of S.aureus and S.epidimidis isolates were susceptible to teicoplanin and vancomycin from 2001 to 2003. However, 1 isolate of S.haemolyticus was resistant and 9 isolates intermediate to teicoplanin. The minimal inhibitory concentration of teicoplanin did not correlate well with zone diameter, when inoculum increased by 100 folds, the zone diameters of teicoplanin decreased more greatly than those of vancomycin. In 2002, severe outbreaks caused by MRSA strains had been found in ICU and RCU wards. Teicoplanin and vancomycin had good activity against clinical isolates of Staphylococci spp . Teicoplanin was less active than vancomycin against S.haemolyticus . Most of S.haemolyticus isolates were intermediate to teicoplanin. Antimicrobial susceptibility testing of teicoplanin was influenced by the diffusion speed in the agar and inoculum size.展开更多
Objective To evaluate the clinical efficacy of dihydroartemisinin-mefloquine on acute uncomplicated falciparum malaria. Methods Fifty-four patients with symptomatic falciparum malaria were allocated to receive oral ...Objective To evaluate the clinical efficacy of dihydroartemisinin-mefloquine on acute uncomplicated falciparum malaria. Methods Fifty-four patients with symptomatic falciparum malaria were allocated to receive oral dihydroartemisinin at a single dose of 120?mg on day 1, followed by mefloquine, 750?mg and 500?mg on days 2 and 3, respectively. Follow-up was performed on days 1,2,3,4,7,14,21, and 28. Results All patients had a rapid initial response to treatment. The parasite clearance time (PCT) after treatment was 30.7±3.6 hours. The fever subsidence time (FST) after treatment was 21.2±2.8 hours. Two patients had a recrudescence 21 and 25 days respectively after the disappearance of parasitemia, hence the recrudescence rate was 3.7% and the cure rate was 96.3%. No serious adverse effects were observed, only mild and transient nausea, vomiting and loss of appetite. Conclusion A combination of dihydroartemisinin and mefloquine is effective in the treatment of acute uncomplicated falciparum malaria.展开更多
Objective： To study the clinical characteristics, treatment, and prognosis of thyroid cancer in children and adolescents. Methods： We performed a retrospective analysis of clinical data from 83 cases of thyroid canc...Objective： To study the clinical characteristics, treatment, and prognosis of thyroid cancer in children and adolescents. Methods： We performed a retrospective analysis of clinical data from 83 cases of thyroid cancer in children and adolescents from January 1990 to December 2010. We compared extra-thyroid extension, lymph node metastasis, distant metastasis, and prognosis between pediatric patients 〈12 years of age （27 cases） and those 〉 12 years of age （56 cases）. All the patients agreed to undergo thyroidectomy and endocrine therapy, and the consent was obtained from parents or guardians. Results： Histopathology included papillary carcinoma in 67 cases, papillary carcinoma with partial follicular growth pattern in 1 case, papillary carcinoma with squamous metaplasia in 4 cases, follicular carcinoma in 7 cases, medullary carcinoma in 3 cases, and poorly differentiated carcinoma in 1 case. The total lymph node metastasis rate was 78.31%. Patients ≤12 years of age showed a higher rate of lymph node me- tastasis than the older group （92.59% vs. 71.43%, P=0.028）. The incidence rate in females in the older group was higher than that in the younger group （80.36% vs. 59.26%, P=0.041）. There were no significant differences in extra-thyroid extension, distant metastasis, survival rate, or recurrent disease between the two groups. Conclusions： The lymph node metastasis of thyroid cancer is higher in patients ≤12 years of age than in those 〉12 years of age; the incidence rate is higher in females than in males. Childhood thyroid cancer has a good prognosis, surgery being the most effective treatment. Choosing a reasonable surgery method and comprehensive postoperative treatment can achieve a cure and satisfactory survival rate.展开更多
文摘The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in fabrication.An isotropic synthetic pitch was prepared by a chlorine-and/or nitrogen-induced sub-stitution polymerization reaction method using aromatic hydrocarbon precursors containing Cl and N,which for this study were chloromethyl naphthalene and quinoline.This method was verified by investigating the structural changes under different synthesis conditions,and the synthesis mechanism induced by aromatics containing Cl was also probed.The result shows that the pyridinic N in quinoline contains a lone pair of electrons,and is an effective active site to induce the polymerization reaction by coupling with aromatic hydrocarbons containing Cl.The reaction between such free radicals causes strong homopolymerization and oligomeriza-tion.A higher reaction temperature and longer reaction time significantly increased the degree of polymerization and thus increased the softening point of the pitch.A linear molecular structure was formed by the Cl substitution reaction,which produced a highly spinnable pitch with a softening point of 258.6℃,and carbon fibers with a tensile strength of 1163.82 MPa were obtained.This study provides a relatively simple and safe method for the preparation of high-quality spinnable pitch.
基金Financially supported by the Opening Fund of National Key Laboratory of State Heavy Oil University of Petroleum+1 种基金 Beijing (2003-04) and the Scientific Research Foundation (SRF) for the Returned Overseas Chinese Scholars (ROCS) State Education Minis
文摘The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particles was smiliar to that of kaolinite clay. On the surface of BS, both toluene insoluble organic matter and structural OH group are detected at the same time. The surface characteristics imparted a bi-wettable nature to the BS. As a result, the BS is able to stabilize fine water emulsion in the bitumen phase. The organic matter associated with BS is a possible factor of the fouling on catalyst and equipment.
基金financially supported by the Science and Technology Administration of Shandong Province, China (20042504)
文摘In this paper, studies were carried out to extract astaxanthin from discharged wastewater during the production of chitin and to reveal the scavenging effect of the obtained pigment on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. Different ratios of dichloromethane/methanol (V/V) were used to extract astaxanthin. When the ratio of dichloromethane/methanol was 2:8 and the ratio between the mixed organic solvent (dichloromethane/methanol, 2:8, V/V) and wastewater was 1:1, the highest yield of pigment was obtained (8.4 mg/ 50 mL). The concentration of free astaxanthin in the obtained pigment analyzed by HPLC was 30.02%. The obtained pigment possessed strong scavenging ability on DPPH radical and IC50 was 0.84mg/ml.
文摘The purpose of this subject was to investigate molecular epidemiology of oxacillin-resistant Staphylococcus aureus (MRSA) isolated from hospitalized patients, and to survey the in vitro activity of teicoplanin, vancomycin and other 9 antibiotics against Staphylococcus species . MRSA were detected by oxacillin-NaCl-containing screen agar. The homology of nosocomial MRSA from ICU and RCU was determined by pulse-field gel electrophoresis. Agar diffusion, E test and agar dilution were used to compare the in vitro activity of teicoplanin and vancomycin against Staphylococcus spp from 2001 to 2003 at Peking Union Medical College Hospital. WHONET-5.3 software was used to analyze the antimicrobial susceptibility data. From 2001 to 2003, the prevalences of MRSA were 56.5%, 65.3%, 64.7%, respectively. PFGE found most of MRSA from ICU and RCU were closely related. All of S.aureus and S.epidimidis isolates were susceptible to teicoplanin and vancomycin from 2001 to 2003. However, 1 isolate of S.haemolyticus was resistant and 9 isolates intermediate to teicoplanin. The minimal inhibitory concentration of teicoplanin did not correlate well with zone diameter, when inoculum increased by 100 folds, the zone diameters of teicoplanin decreased more greatly than those of vancomycin. In 2002, severe outbreaks caused by MRSA strains had been found in ICU and RCU wards. Teicoplanin and vancomycin had good activity against clinical isolates of Staphylococci spp . Teicoplanin was less active than vancomycin against S.haemolyticus . Most of S.haemolyticus isolates were intermediate to teicoplanin. Antimicrobial susceptibility testing of teicoplanin was influenced by the diffusion speed in the agar and inoculum size.
文摘Objective To evaluate the clinical efficacy of dihydroartemisinin-mefloquine on acute uncomplicated falciparum malaria. Methods Fifty-four patients with symptomatic falciparum malaria were allocated to receive oral dihydroartemisinin at a single dose of 120?mg on day 1, followed by mefloquine, 750?mg and 500?mg on days 2 and 3, respectively. Follow-up was performed on days 1,2,3,4,7,14,21, and 28. Results All patients had a rapid initial response to treatment. The parasite clearance time (PCT) after treatment was 30.7±3.6 hours. The fever subsidence time (FST) after treatment was 21.2±2.8 hours. Two patients had a recrudescence 21 and 25 days respectively after the disappearance of parasitemia, hence the recrudescence rate was 3.7% and the cure rate was 96.3%. No serious adverse effects were observed, only mild and transient nausea, vomiting and loss of appetite. Conclusion A combination of dihydroartemisinin and mefloquine is effective in the treatment of acute uncomplicated falciparum malaria.
文摘Objective： To study the clinical characteristics, treatment, and prognosis of thyroid cancer in children and adolescents. Methods： We performed a retrospective analysis of clinical data from 83 cases of thyroid cancer in children and adolescents from January 1990 to December 2010. We compared extra-thyroid extension, lymph node metastasis, distant metastasis, and prognosis between pediatric patients 〈12 years of age （27 cases） and those 〉 12 years of age （56 cases）. All the patients agreed to undergo thyroidectomy and endocrine therapy, and the consent was obtained from parents or guardians. Results： Histopathology included papillary carcinoma in 67 cases, papillary carcinoma with partial follicular growth pattern in 1 case, papillary carcinoma with squamous metaplasia in 4 cases, follicular carcinoma in 7 cases, medullary carcinoma in 3 cases, and poorly differentiated carcinoma in 1 case. The total lymph node metastasis rate was 78.31%. Patients ≤12 years of age showed a higher rate of lymph node me- tastasis than the older group （92.59% vs. 71.43%, P=0.028）. The incidence rate in females in the older group was higher than that in the younger group （80.36% vs. 59.26%, P=0.041）. There were no significant differences in extra-thyroid extension, distant metastasis, survival rate, or recurrent disease between the two groups. Conclusions： The lymph node metastasis of thyroid cancer is higher in patients ≤12 years of age than in those 〉12 years of age; the incidence rate is higher in females than in males. Childhood thyroid cancer has a good prognosis, surgery being the most effective treatment. Choosing a reasonable surgery method and comprehensive postoperative treatment can achieve a cure and satisfactory survival rate.
