Recent work revealed that, in the genomes of polyploid wheat, there exists a class of low_copy and chromosome_specific sequences that are labile upon polyploid formation. This class of sequences was proposed to play ...Recent work revealed that, in the genomes of polyploid wheat, there exists a class of low_copy and chromosome_specific sequences that are labile upon polyploid formation. This class of sequences was proposed to play a critical role in the stabilization and establishment of nascent plant polyploids as new species. To further study this issue, five wheat chromosome 7B_specific sequences, isolated from common wheat (Triticum aestivum L.) by chromosome microdissection, were characterized. The sequences were studied by genomic Southern hybridizations on a collection of polyploid wheats and their diploid progenitors. Four sequences hybridized to all polyploid species, but at the diploid level to only species closely related to the B_genome of polyploid wheat. This indicates that these sequences originated with the divergence of the diploid species, and was then vertically transmitted to polyploids. One sequence hybridized to all species at both the diploid and polyploid levels, suggesting its elimination after the polyploid wheat formation. The hybridization of this sequence to two synthetic polyploid wheats indicated that sequence elimination is a rapid event and probably related to methylation status of the sequence. Based on the above results, we suggest that selective changes of low_copy sequences occur rapidly after polyploid formation, which may contribute to the differentiation of chromosomes in newly formed allopolyploid wheats.展开更多
The coexistence of thyroid diseases with primary hyperparathyroidism (PHPT) can present a challenge in the clinical diagnosis and management for these patients. This study aims to determine the frequency of coexisting...The coexistence of thyroid diseases with primary hyperparathyroidism (PHPT) can present a challenge in the clinical diagnosis and management for these patients. This study aims to determine the frequency of coexisting thyroid gland lesions in a consecutive series patients with PHPT, and to analyze the clinical features, diagnosis and treatment of these patients. Twenty-two cases of a total of 52 PHPT patients who had synchronous thyroid and parathyroid pathology were surgically managed in this study. Thirteen patients had ipsilateral thyroid nodules, and 9 patients had thyroid nodules in contralateral or bilateral side. Seven patients underwent direct parathyroidectomy and hemithyroidectomy via a mini-incision (about 3 cm), while other 15 procedures were converted to Kocher incision. Seventeen nodular goiter (32.7%), 2 thyroiditis (3.8%), 2 thyroid adenoma (3.8%) and 1 thyroid carcinoma (1.9%) coexisting with parathyroid adenoma were pathologically diagnosed. The sensitivity of preoperative ultra-sonography (US) and methoxy-isobutyl-isonitrile (MIBI) scintigraphy for parathyroid lesions was 63.6% and 85.7%; and the overall positive predictive values for MIBI and US were 100% and 95.5% respectively. A high incidence of thyroid diseases that coexisted with PHPT in literatures was briefly reviewed. Our study illustrated the need for clinical awareness of concomitant PHPT and thyroid disease. A combination of US, computed tomography (CT) and MIBI scintigraphy would be recommended for preoperative localization of enlarged parathyroid adenoma and for evaluation of thyroid lesions. Synchronous treatment of asso-ciated thyroid abnormalities is desirable, and open minimally invasive surgical approach with additional resection of isolated ipsilateral thyroid nodules is possible in some of these patients.展开更多
Objective: To investigate the association of Graves’ disease and Graves’ ophthalmopathy with the C/T transition polymorphism at position –318 of promoter and the A/G transition polymorphism at position 49 of exon 1...Objective: To investigate the association of Graves’ disease and Graves’ ophthalmopathy with the C/T transition polymorphism at position –318 of promoter and the A/G transition polymorphism at position 49 of exon 1 within cytotoxic T lymphocyte associated antigen-4 (CTLA-4) gene. Methods: Thirty-three patients with ophthalmopathy of Graves’ disease, fifty-six Graves’ patients without ophthalmopathy and sixty normal subjects as control were involved in the present case-control study. The polymorphisms were evaluated by polymerase chain reaction fragment length polymorphism (PCR-RFLP). Com-parisons were made of gene frequencies and allele frequencies between the groups. Results: The gene frequencies of CT and allele frequencies of T were much higher in Graves’ patients with ophthalmopathy than that in the group without ophthalmopathy (P=0.020, P=0.019). The gene frequencies of GG and allele frequencies of G in patients with Graves’ disease were significantly increased as compared with control group (P=0.008, P=0.007). The data suggest that smokers with Graves’ disease seemed to be more predisposed to ophthalmopathy than non-smokers (P=0.018). Conclusion: Our results suggest that an allele of T at position –318 of promoter is associated with genetic susceptibility to Graves’ ophthalmopathy while an allele of G at position 49 of exon 1 is associated with genetic susceptibility to Graves’ disease instead. Smoking is believed to be a major risk factor for ophthalmo-pathy.展开更多
In this work,ethylene glycol monomethylether(EE) was chosen as an entrainer for the azeotropic distillation of 1,3,5-trimethylbenzene+1-methyl-2-ethylbenzene system to investigate the influence of the entrainer on vap...In this work,ethylene glycol monomethylether(EE) was chosen as an entrainer for the azeotropic distillation of 1,3,5-trimethylbenzene+1-methyl-2-ethylbenzene system to investigate the influence of the entrainer on vapor liquid equilibrium(VLE) of this system.Three sets of binary VLE data in the system consisting of EE + 1,3,5-trimethylbenzene +1-methyl-2-ethylbenzene were measured using the Dvorak-Boublik still.The binary parameters of NRTL model were correlated by using the likelihood method.The ternary VLE data of the system were measured as well and were predicted by using the binary parameters of NRTL model.The test results indicated that the binary data passed the thermodynamic consistency tests,and the difference between the predicted values of ternary VLE and the experimental data reached the research standard for VLE data.Addition of EE had a great influence on the relative volatility between 1,3,5-trimethylbenzene and 1-methl-2-ethyl-benzene:when the ratio of solvent was 4,and the relative volatility between 1,3,5-trimethylbenzene and 1-methyl-2-ethylbenzene increased from 1.0125(without solvent addition) to 1.283.展开更多
Objective To investigate the effects of substitutive and suppressive doses of levothyroxine on bone metabolism in patients with differentiated thyroid carcinoma after surgery and 131I ablation. Methods The patients, w...Objective To investigate the effects of substitutive and suppressive doses of levothyroxine on bone metabolism in patients with differentiated thyroid carcinoma after surgery and 131I ablation. Methods The patients, who had received levothyroxine(L-T4) for at least 3 years for treating their differentiated thyroid carcinoma after surgery and 131I therapy, were classified into substitutive group and suppressive group according to the levels of serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH). We compared the levels of FT3, FT4, TSH, serum parathyroid hormone (PTH), serum calcium (Ca), serum phosphate (P), serum alkaline phosphates (ALP) and Bone mineral density (BMD) to those of healthy volunteers well matched for sex, age, menopausal status, and body mass index (BMI). Results No significant differences were found in the bone density and biochemical parameters of bone metabolism of the subjects treated with substitutive or suppressive doses of L-T4 compared with the control subgroup. No significant differences were observed among the subgroups according to accumulative doses of 131I. No bone fracture was found in all the patients. Conclusion The substitutive and suppressive doses of L-T4 are safe and necessary for patients with differentiated thyroid carcinoma after surgery and 131I therapy. Such treatment for 3 years is not associated with increased risk of osteoporosis. Much longer term of follow up is still needed in patients receiving substitutive and suppressive doses of L-T4.展开更多
Using a standard cytochrome c oxidase I sequence,DNA barcoding has been shown to be effective to distinguish known species and to discover cryptic species. Here we assessed the efficiency of DNA barcoding for the amph...Using a standard cytochrome c oxidase I sequence,DNA barcoding has been shown to be effective to distinguish known species and to discover cryptic species. Here we assessed the efficiency of DNA barcoding for the amphipod genus Gammarus from China. The maximum intraspecific divergence for widespread species,Gammarus lacustris,was 3.5%,and mean interspecific divergence reached 21.9%. We presented a conservative benchmark for determining provisional species using maximum intraspecific divergence of Gammarus lacustris. Thirty-one species possessed distinct barcode clusters. Two species were comprised of highly divergent clades with strong neighbor-joining bootstrap values,and likely indicated the presence of cryptic species. Although DNA barcoding is effective,future identification of species of Gammarus should incorporate DNA barcoding and morphological detection.展开更多
In order to study the variation of temperature to mechanical stimulation threshold of typical liquid propellants(ADN-based HAN-based and nitromethane),the critical impact energy and critical friction of three propella...In order to study the variation of temperature to mechanical stimulation threshold of typical liquid propellants(ADN-based HAN-based and nitromethane),the critical impact energy and critical friction of three propellants under different temperatures were studied by using BAM fall hammer impact sensitivity tester and BAM friction sensitivity tester.Experiments show that under 80℃,60℃,40℃and 20℃,the critical impact energy of HAN-based are 20 J,15 J,15 J,15 J;the critical impact energy of nitromethane are 2 J,2 J,2 J,2 J;and the critical impact energy of ADN-based are<1 J,3 J,7.5 J,15 J.It reveals that HAN-based propellant has the highest critical impact energy,while nitromethane propellant has the lowest critical impact energy.ADN-based propellant has a notable decrease on its critical impact energy with temperature decreasing,indicating that temperature has a significant effect on impact sensitivity of ADN-based propellant.The critical friction of three samples are all higher than 360 N at 80℃,60℃,40℃and 20℃,which shows that the samples are not sensitive to friction,and temperature has no significant effect on the critical friction of three samples.The mechanical stimulations that may be encountered during the production and use of liquid propellants are analyzed,which takes certain working conditions and the temperature coupling effect into consideration,thereby providing support for safety management of liquid propellants during production and storage process.展开更多
The effect of benzoyl peroxide (BPO) on polypropylene (PP) degradation in supercritical water was investigated with the aim of developing a process for recycling of waste plastics. A series of experiments with and...The effect of benzoyl peroxide (BPO) on polypropylene (PP) degradation in supercritical water was investigated with the aim of developing a process for recycling of waste plastics. A series of experiments with and without BPO were carried out at temperatures of 653 K and 673 K under pressure about 26 MPa for 30, 75 and 120 min respectively. Products were analyzed by an Ostward-type viscometer, gas chromatography and spectrometry (GC/MS) etc. The results indicated that mean molecular weight of the samples decreased greatly along with the time elapsing or with the temperature increasing, and PP was decomposed to Miphatic and cycloparaftinic hydrocarbons but a few benzenoid hydrocarbons. By comparing the experiments with and without BPO, it was made clear that BPO is an effective additive on PP degradation in supercritical water.展开更多
Because of the complicated interplay between the prefractionator and main distillation column involved,the black-hole problem might occur and prohibit the assignment of four specifications to dividing-wall distillatio...Because of the complicated interplay between the prefractionator and main distillation column involved,the black-hole problem might occur and prohibit the assignment of four specifications to dividing-wall distillation columns(DWDCs)(e.g., the three main product compositions plus an impurity ratio in the intermediate product), which lowers terribly process flexibility and operability. In this paper, a feed thermal condition adjustment strategy, achieved by the installation of a pre-heater in feed pipeline, is employed to eliminate the black-hole problem and serve to enhance process flexibility and operability. Through the strong influence to the overall mass and energy balance of the DWDC, the feed thermal condition adjustment can alter the interlinking flows between the thermally coupled prefractionator and main distillation column and work effectively to coordinate their relationship. A DWDC separating a benzene, toluene, and o-xylene mixture is chosen to ascertain the feasibility of the philosophy proposed. The static and dynamic studies demonstrate that the feed thermal condition adjustment is an effective way to refine process design and can completely eliminate the black-hole problem and elevate consequently process flexibility and operability.展开更多
Objective To evaluate the application of 99Tcm-sestamibi dual-phase parathyroid scintigraphy in the preoperative localization in patients with primary hyperparathyroidism and to compare the diagnostic efficacy of vari...Objective To evaluate the application of 99Tcm-sestamibi dual-phase parathyroid scintigraphy in the preoperative localization in patients with primary hyperparathyroidism and to compare the diagnostic efficacy of various imaging modalities. Methods Ninety-two consecutive patients, diagnosed as hyperparathyroidism and presented with hypercalcaemia as the predominant symptom, were included. All the patients underwent dual-phase parathyroid scintigraphy using 99Tcm-sestamibi and parathyroid ultrasound scan. Among them, 48 patients underwent parathyroid computed tomography (CT). All patients were referred for parathyroidectomy. Results 99Tcm-sestamibi dual-phase parathyroid scintigraphy revealed the diagnostic sensitivity of 76.5%, 80%, 75% and 33.3% for the subgroup of single adenomas, multiple adenomas, ectopic parathyroid and parathyroid hyperplasia respectively. The specificity was 100% for all leisons. 99Tcm-sestamibi dual-phase parathyroid scintigraphy was proved to be superior to the other imaging modalities (ultrasound and CT) in terms of the preoperative diagnostic accuracy. The lesion weight was found to be an underlying factor leading to the false negative result. Conclusion 99Tcm-sestamibi dual-phase parathyroid scintigraphy was found to have higher diagnostic accuracy in comparison with other imaging modalities and is recommended preoperatively in order to reduce the sugery time and unnecessary neck exploration.展开更多
The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid (TPA). The liquid-phase catalytic oxidation of p-xylene (PX) to TPA is regarded as a critical and efficient chemi...The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid (TPA). The liquid-phase catalytic oxidation of p-xylene (PX) to TPA is regarded as a critical and efficient chemical process in industry [ 1 ]. PX oxidation reaction involves many complex side reactions, among which acetic acid combustion and PX combustion are the most important. As the target product of this oxidation process, the quality and yield of TPA are of great concern. However, the improvement of the qualified product yield can bring about the high energy consumption, which means that the economic objectives of this process cannot be achieved simulta- neously because the two objectives are in conflict with each other. In this paper, an improved self-adaptive multi-objective differential evolution algorithm was proposed to handle the multi-objective optimization prob- lems. The immune concept is introduced to the self-adaptive multi-objective differential evolution algorithm (SADE) to strengthen the local search ability and optimization accuracy. The proposed algorithm is successfully tested on several benchmark test problems, and the performance measures such as convergence and divergence metrics are calculated. Subsequently, the multi-objective optimization of an industrial PX oxidation process is carried out using the proposed immune self-adaptive multi-objective differential evolution algorithm (ISADE). Optimization results indicate that application oflSADE can greatly improve the yield of TPA with low combustion loss without degenerating TA quality.展开更多
PURPOSE: To observe the effects of acupuncture on the pituitary-thyroid axis in rabbits with fracture. METHOD: 36 male rabbits with a 3-mm width experimental defect in the middle segment of the left radius were random...PURPOSE: To observe the effects of acupuncture on the pituitary-thyroid axis in rabbits with fracture. METHOD: 36 male rabbits with a 3-mm width experimental defect in the middle segment of the left radius were randomly divided into the treatment group and control group, and the changes in serum T3, T4 and TSH contents in different weeks were investigated. RESULTS: Serum T3, T4 and TSH contents in the treatment group all were higher than those in the control group, with statistically significant differences in the contents of T4 and TSH in the second week and T3 content in the fourth week (P展开更多
文摘Recent work revealed that, in the genomes of polyploid wheat, there exists a class of low_copy and chromosome_specific sequences that are labile upon polyploid formation. This class of sequences was proposed to play a critical role in the stabilization and establishment of nascent plant polyploids as new species. To further study this issue, five wheat chromosome 7B_specific sequences, isolated from common wheat (Triticum aestivum L.) by chromosome microdissection, were characterized. The sequences were studied by genomic Southern hybridizations on a collection of polyploid wheats and their diploid progenitors. Four sequences hybridized to all polyploid species, but at the diploid level to only species closely related to the B_genome of polyploid wheat. This indicates that these sequences originated with the divergence of the diploid species, and was then vertically transmitted to polyploids. One sequence hybridized to all species at both the diploid and polyploid levels, suggesting its elimination after the polyploid wheat formation. The hybridization of this sequence to two synthetic polyploid wheats indicated that sequence elimination is a rapid event and probably related to methylation status of the sequence. Based on the above results, we suggest that selective changes of low_copy sequences occur rapidly after polyploid formation, which may contribute to the differentiation of chromosomes in newly formed allopolyploid wheats.
基金Project (No. 2007C34001) supported by the Science and TechnologyResearch Foundation of Zhejiang Province, China
文摘The coexistence of thyroid diseases with primary hyperparathyroidism (PHPT) can present a challenge in the clinical diagnosis and management for these patients. This study aims to determine the frequency of coexisting thyroid gland lesions in a consecutive series patients with PHPT, and to analyze the clinical features, diagnosis and treatment of these patients. Twenty-two cases of a total of 52 PHPT patients who had synchronous thyroid and parathyroid pathology were surgically managed in this study. Thirteen patients had ipsilateral thyroid nodules, and 9 patients had thyroid nodules in contralateral or bilateral side. Seven patients underwent direct parathyroidectomy and hemithyroidectomy via a mini-incision (about 3 cm), while other 15 procedures were converted to Kocher incision. Seventeen nodular goiter (32.7%), 2 thyroiditis (3.8%), 2 thyroid adenoma (3.8%) and 1 thyroid carcinoma (1.9%) coexisting with parathyroid adenoma were pathologically diagnosed. The sensitivity of preoperative ultra-sonography (US) and methoxy-isobutyl-isonitrile (MIBI) scintigraphy for parathyroid lesions was 63.6% and 85.7%; and the overall positive predictive values for MIBI and US were 100% and 95.5% respectively. A high incidence of thyroid diseases that coexisted with PHPT in literatures was briefly reviewed. Our study illustrated the need for clinical awareness of concomitant PHPT and thyroid disease. A combination of US, computed tomography (CT) and MIBI scintigraphy would be recommended for preoperative localization of enlarged parathyroid adenoma and for evaluation of thyroid lesions. Synchronous treatment of asso-ciated thyroid abnormalities is desirable, and open minimally invasive surgical approach with additional resection of isolated ipsilateral thyroid nodules is possible in some of these patients.
文摘Objective: To investigate the association of Graves’ disease and Graves’ ophthalmopathy with the C/T transition polymorphism at position –318 of promoter and the A/G transition polymorphism at position 49 of exon 1 within cytotoxic T lymphocyte associated antigen-4 (CTLA-4) gene. Methods: Thirty-three patients with ophthalmopathy of Graves’ disease, fifty-six Graves’ patients without ophthalmopathy and sixty normal subjects as control were involved in the present case-control study. The polymorphisms were evaluated by polymerase chain reaction fragment length polymorphism (PCR-RFLP). Com-parisons were made of gene frequencies and allele frequencies between the groups. Results: The gene frequencies of CT and allele frequencies of T were much higher in Graves’ patients with ophthalmopathy than that in the group without ophthalmopathy (P=0.020, P=0.019). The gene frequencies of GG and allele frequencies of G in patients with Graves’ disease were significantly increased as compared with control group (P=0.008, P=0.007). The data suggest that smokers with Graves’ disease seemed to be more predisposed to ophthalmopathy than non-smokers (P=0.018). Conclusion: Our results suggest that an allele of T at position –318 of promoter is associated with genetic susceptibility to Graves’ ophthalmopathy while an allele of G at position 49 of exon 1 is associated with genetic susceptibility to Graves’ disease instead. Smoking is believed to be a major risk factor for ophthalmo-pathy.
基金supported by the SINOPEC Corporation (Contact No. 408069)
文摘In this work,ethylene glycol monomethylether(EE) was chosen as an entrainer for the azeotropic distillation of 1,3,5-trimethylbenzene+1-methyl-2-ethylbenzene system to investigate the influence of the entrainer on vapor liquid equilibrium(VLE) of this system.Three sets of binary VLE data in the system consisting of EE + 1,3,5-trimethylbenzene +1-methyl-2-ethylbenzene were measured using the Dvorak-Boublik still.The binary parameters of NRTL model were correlated by using the likelihood method.The ternary VLE data of the system were measured as well and were predicted by using the binary parameters of NRTL model.The test results indicated that the binary data passed the thermodynamic consistency tests,and the difference between the predicted values of ternary VLE and the experimental data reached the research standard for VLE data.Addition of EE had a great influence on the relative volatility between 1,3,5-trimethylbenzene and 1-methl-2-ethyl-benzene:when the ratio of solvent was 4,and the relative volatility between 1,3,5-trimethylbenzene and 1-methyl-2-ethylbenzene increased from 1.0125(without solvent addition) to 1.283.
基金grants from Foundation of Shanghai Science and Technology, China (024119053).
文摘Objective To investigate the effects of substitutive and suppressive doses of levothyroxine on bone metabolism in patients with differentiated thyroid carcinoma after surgery and 131I ablation. Methods The patients, who had received levothyroxine(L-T4) for at least 3 years for treating their differentiated thyroid carcinoma after surgery and 131I therapy, were classified into substitutive group and suppressive group according to the levels of serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH). We compared the levels of FT3, FT4, TSH, serum parathyroid hormone (PTH), serum calcium (Ca), serum phosphate (P), serum alkaline phosphates (ALP) and Bone mineral density (BMD) to those of healthy volunteers well matched for sex, age, menopausal status, and body mass index (BMI). Results No significant differences were found in the bone density and biochemical parameters of bone metabolism of the subjects treated with substitutive or suppressive doses of L-T4 compared with the control subgroup. No significant differences were observed among the subgroups according to accumulative doses of 131I. No bone fracture was found in all the patients. Conclusion The substitutive and suppressive doses of L-T4 are safe and necessary for patients with differentiated thyroid carcinoma after surgery and 131I therapy. Such treatment for 3 years is not associated with increased risk of osteoporosis. Much longer term of follow up is still needed in patients receiving substitutive and suppressive doses of L-T4.
基金supported by the National Natural Sciences Foundation of China (NSFC-30499341/30770268/30870473)Beijing Financial Budget Index (2008-NO.0178)the Beijing Natural Science Foundation (5082013)
文摘Using a standard cytochrome c oxidase I sequence,DNA barcoding has been shown to be effective to distinguish known species and to discover cryptic species. Here we assessed the efficiency of DNA barcoding for the amphipod genus Gammarus from China. The maximum intraspecific divergence for widespread species,Gammarus lacustris,was 3.5%,and mean interspecific divergence reached 21.9%. We presented a conservative benchmark for determining provisional species using maximum intraspecific divergence of Gammarus lacustris. Thirty-one species possessed distinct barcode clusters. Two species were comprised of highly divergent clades with strong neighbor-joining bootstrap values,and likely indicated the presence of cryptic species. Although DNA barcoding is effective,future identification of species of Gammarus should incorporate DNA barcoding and morphological detection.
文摘In order to study the variation of temperature to mechanical stimulation threshold of typical liquid propellants(ADN-based HAN-based and nitromethane),the critical impact energy and critical friction of three propellants under different temperatures were studied by using BAM fall hammer impact sensitivity tester and BAM friction sensitivity tester.Experiments show that under 80℃,60℃,40℃and 20℃,the critical impact energy of HAN-based are 20 J,15 J,15 J,15 J;the critical impact energy of nitromethane are 2 J,2 J,2 J,2 J;and the critical impact energy of ADN-based are<1 J,3 J,7.5 J,15 J.It reveals that HAN-based propellant has the highest critical impact energy,while nitromethane propellant has the lowest critical impact energy.ADN-based propellant has a notable decrease on its critical impact energy with temperature decreasing,indicating that temperature has a significant effect on impact sensitivity of ADN-based propellant.The critical friction of three samples are all higher than 360 N at 80℃,60℃,40℃and 20℃,which shows that the samples are not sensitive to friction,and temperature has no significant effect on the critical friction of three samples.The mechanical stimulations that may be encountered during the production and use of liquid propellants are analyzed,which takes certain working conditions and the temperature coupling effect into consideration,thereby providing support for safety management of liquid propellants during production and storage process.
基金Supported by the National Natural Science Foundation of China (No.59972022).
文摘The effect of benzoyl peroxide (BPO) on polypropylene (PP) degradation in supercritical water was investigated with the aim of developing a process for recycling of waste plastics. A series of experiments with and without BPO were carried out at temperatures of 653 K and 673 K under pressure about 26 MPa for 30, 75 and 120 min respectively. Products were analyzed by an Ostward-type viscometer, gas chromatography and spectrometry (GC/MS) etc. The results indicated that mean molecular weight of the samples decreased greatly along with the time elapsing or with the temperature increasing, and PP was decomposed to Miphatic and cycloparaftinic hydrocarbons but a few benzenoid hydrocarbons. By comparing the experiments with and without BPO, it was made clear that BPO is an effective additive on PP degradation in supercritical water.
基金Supported by the National Natural Science Foundation of China(21076015,21376018,21576014,21676011)
文摘Because of the complicated interplay between the prefractionator and main distillation column involved,the black-hole problem might occur and prohibit the assignment of four specifications to dividing-wall distillation columns(DWDCs)(e.g., the three main product compositions plus an impurity ratio in the intermediate product), which lowers terribly process flexibility and operability. In this paper, a feed thermal condition adjustment strategy, achieved by the installation of a pre-heater in feed pipeline, is employed to eliminate the black-hole problem and serve to enhance process flexibility and operability. Through the strong influence to the overall mass and energy balance of the DWDC, the feed thermal condition adjustment can alter the interlinking flows between the thermally coupled prefractionator and main distillation column and work effectively to coordinate their relationship. A DWDC separating a benzene, toluene, and o-xylene mixture is chosen to ascertain the feasibility of the philosophy proposed. The static and dynamic studies demonstrate that the feed thermal condition adjustment is an effective way to refine process design and can completely eliminate the black-hole problem and elevate consequently process flexibility and operability.
文摘Objective To evaluate the application of 99Tcm-sestamibi dual-phase parathyroid scintigraphy in the preoperative localization in patients with primary hyperparathyroidism and to compare the diagnostic efficacy of various imaging modalities. Methods Ninety-two consecutive patients, diagnosed as hyperparathyroidism and presented with hypercalcaemia as the predominant symptom, were included. All the patients underwent dual-phase parathyroid scintigraphy using 99Tcm-sestamibi and parathyroid ultrasound scan. Among them, 48 patients underwent parathyroid computed tomography (CT). All patients were referred for parathyroidectomy. Results 99Tcm-sestamibi dual-phase parathyroid scintigraphy revealed the diagnostic sensitivity of 76.5%, 80%, 75% and 33.3% for the subgroup of single adenomas, multiple adenomas, ectopic parathyroid and parathyroid hyperplasia respectively. The specificity was 100% for all leisons. 99Tcm-sestamibi dual-phase parathyroid scintigraphy was proved to be superior to the other imaging modalities (ultrasound and CT) in terms of the preoperative diagnostic accuracy. The lesion weight was found to be an underlying factor leading to the false negative result. Conclusion 99Tcm-sestamibi dual-phase parathyroid scintigraphy was found to have higher diagnostic accuracy in comparison with other imaging modalities and is recommended preoperatively in order to reduce the sugery time and unnecessary neck exploration.
基金Supported by the Shanghai Second Polytechnic University Key Discipline Construction-Control Theory & Control Engineering(No.XXKPY1609)the National Natural Science Foundation of China(61422303)+1 种基金Shanghai Talent Development Funding(H200-2R-15111)2017 Shanghai Second Polytechnic University Cultivation Research Program of Young Teachers(02)
文摘The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid (TPA). The liquid-phase catalytic oxidation of p-xylene (PX) to TPA is regarded as a critical and efficient chemical process in industry [ 1 ]. PX oxidation reaction involves many complex side reactions, among which acetic acid combustion and PX combustion are the most important. As the target product of this oxidation process, the quality and yield of TPA are of great concern. However, the improvement of the qualified product yield can bring about the high energy consumption, which means that the economic objectives of this process cannot be achieved simulta- neously because the two objectives are in conflict with each other. In this paper, an improved self-adaptive multi-objective differential evolution algorithm was proposed to handle the multi-objective optimization prob- lems. The immune concept is introduced to the self-adaptive multi-objective differential evolution algorithm (SADE) to strengthen the local search ability and optimization accuracy. The proposed algorithm is successfully tested on several benchmark test problems, and the performance measures such as convergence and divergence metrics are calculated. Subsequently, the multi-objective optimization of an industrial PX oxidation process is carried out using the proposed immune self-adaptive multi-objective differential evolution algorithm (ISADE). Optimization results indicate that application oflSADE can greatly improve the yield of TPA with low combustion loss without degenerating TA quality.
文摘PURPOSE: To observe the effects of acupuncture on the pituitary-thyroid axis in rabbits with fracture. METHOD: 36 male rabbits with a 3-mm width experimental defect in the middle segment of the left radius were randomly divided into the treatment group and control group, and the changes in serum T3, T4 and TSH contents in different weeks were investigated. RESULTS: Serum T3, T4 and TSH contents in the treatment group all were higher than those in the control group, with statistically significant differences in the contents of T4 and TSH in the second week and T3 content in the fourth week (P