In the context of banning gated communities, blocks returning to the human-oriented scale become the new normal, and pedestrian system design will be paid more attention in the urban planning field. Oct-Loft Creative ...In the context of banning gated communities, blocks returning to the human-oriented scale become the new normal, and pedestrian system design will be paid more attention in the urban planning field. Oct-Loft Creative Park is a template for open blocks in Shenzhen, with a convenient and humanized pedestrian system. This paper selects the creative park's pedestrian system as the research object, using the environment-behavior theory for analysis. Finally, optimization strategies of pedestrian system will be put forward.展开更多
Epidural analgesia has long been regarded as the gold standard in abdominal surgery. However, concerns regarding risks associated with central neuraxial blockade, catheter placement and the presence of coagulopathy in...Epidural analgesia has long been regarded as the gold standard in abdominal surgery. However, concerns regarding risks associated with central neuraxial blockade, catheter placement and the presence of coagulopathy in patients undergoing liver resection have limited its use. Bilateral erector spinae plane blocks and catheter placement may mimic the effects of epidural analgesia by blocking both somatic and visceral pain while concomitantly avoiding central neuraxial blockade and catheter placement. We describe our experience in using the erector spinae plane block and catheter placement as part of a multimodal analgesia approach in a patient undergoing laparoscopic and another patient undergoing open liver resection. Our findings concur with previous reports which suggest that erector spinae plane blocks may be more efficacious as somatic rather than visceral analgesia. However, we conclude that further studies on factors affecting its efficacy should be conducted in view of the present lack of researched evidence.展开更多
A new open-tubular capillary electrochromatography (OT-CEC) method for analysis of β-lactam antibiotics has been developed with unique block co-polymer coating. To obtain the highly ordered block polymer chains, reve...A new open-tubular capillary electrochromatography (OT-CEC) method for analysis of β-lactam antibiotics has been developed with unique block co-polymer coating. To obtain the highly ordered block polymer chains, reversible addition fragmentation chain transfer radical polymerization method was used to synthesize poly (maleic anhydride-styrene-N-isopropylacrylamide). The prepared block copolymer coating was characterized with NMR, fourier transform infrared spectroscopy and scanning electron microscope. Several key separation factors of OT-CEC, which including polymer amount,stability of the coating, temperature, species of organic additives, buffer pH and concentration, were investigated in detail. Our results indicated that the separation efficiency was improved greatly with the coating capillary and the three test analytes could be baseline separated. Then, the separation mechanism was briefly explored. Moreover, the proposed OT-CEC method displayed promising quantitative analysis property of the three test analytes with good linearity (R2>0.99), repeatability (relative standard deviations <0.9%) and high recovery (95.4%-106.2%). Further, the assay was applied in monitoring the three test β-lactam antibiotics (cephradine, cephalexin and amoxicillin) in serum samples, providing a useful platform for construction of novel polymer coatings in OT-CEC system and for analysis of drugs in real bio-samples.展开更多
Dysfunction of the cystic fibrosis transmembrane con-ductance regulator(CFTR) chloride channel causes cys-tic fibrosis, while inappropriate activity of this channeloccurs in secretory diarrhea and polycystic kidney di...Dysfunction of the cystic fibrosis transmembrane con-ductance regulator(CFTR) chloride channel causes cys-tic fibrosis, while inappropriate activity of this channeloccurs in secretory diarrhea and polycystic kidney dis-ease. Drugs that interact directly with CFTR are there-fore of interest in the treatment of a number of diseasestates. This review focuses on one class of small mol-ecules that interacts directly with CFTR, namely inhibi-tors that act by directly blocking chloride movementthrough the open channel pore. In theory such com-pounds could be of use in the treatment of diarrheaand polycystic kidney disease, however in practice allknown substances acting by this mechanism to inhibitCFTR function lack either the potency or specificity forin vivo use. Nevertheless, this theoretical pharmaco-logical usefulness set the scene for the developmentof more potent, specific CFTR inhibitors. Biophysically,open channel blockers have proven most useful as ex-perimental probes of the structure and function of theCFTR chloride channel pore. Most importantly, the useof these blockers has been fundamental in developing afunctional model of the pore that includes a wide innervestibule that uses positively charged amino acid sidechains to attract both permeant and blocking anionsfrom the cell cytoplasm. CFTR channels are also subjectto this kind of blocking action by endogenous anionspresent in the cell cytoplasm, and recently this blocking effect has been suggested to play a role in the physio-logical control of CFTR channel function, in particular as a novel mechanism linking CFTR function dynamically to the composition of epithelial cell secretions. It has also been suggested that future drugs could target this same pathway as a way of pharmacologically increasing CFTR activity in cystic fibrosis. Studying open channel blockers and their mechanisms of action has resulted in significant advances in our understanding of CFTR as a pharmacological target in disease states, of CFTR chan-nel structure and function, and of how CFTR activity is controlled by its local environment.展开更多
A series of cis-5-norbornene-endo-2,3-dicarboxylic anhydride （NDCA, M1） derivatives （M2-M4） with different types of nonpolar substituted groups were synthesized and characterized by 1H/13C-NMR and mass spectromet...A series of cis-5-norbornene-endo-2,3-dicarboxylic anhydride （NDCA, M1） derivatives （M2-M4） with different types of nonpolar substituted groups were synthesized and characterized by 1H/13C-NMR and mass spectrometry （MS）. Ring- opening metathesis polymerization （ROMP） of these monomers using the Grubbs third generation catalyst （G3） generated high molecular weight polymers with much improved solubility compared with the NDCA＇s homopolymer. It was found that the solubility of these polymers increased with increased substituent＇s steric hindrance. The living polymerization of NDCA derivative containing the bulkiest substituent （M4） catalyzed by G3 in tetrahydrofuran was confirmed by the kinetic studies with low polydispersity indices （PDI） （〈 1.30）. By using sequential ROMP, well-defined diblock copolymers containing anhydride groups were synthesized.展开更多
Styrene-isoprene-styrene（SIS） block copolymer was modified into epoxidized styrene-isoprene-styrene（ESIS） block copolymer with performic acid generated in situ from hydrogen peroxide and formic acid.The structure ...Styrene-isoprene-styrene（SIS） block copolymer was modified into epoxidized styrene-isoprene-styrene（ESIS） block copolymer with performic acid generated in situ from hydrogen peroxide and formic acid.The structure and property of ESIS were characterized by Fourier transform infrared（FT-IR） spectroscopy,gel permeation chromatography（GPC）,thermogravimetric/differential thermogravimetric（TG/DTG）,melt flow rate（MFR） and dynamic mechanical analysis（DMA）,and the reaction mechanism in the process of epoxidation was analyzed.The results showed that C=C double bonds of 1,4-structure were more active than that of 3,4-structure in polyisoprene chains.With epoxidation reaction proceeding,the whole tendency of molecular weight increased and molecular weight distribution widened,and MFR firstly increased and latterly decreased.The heat resistance of ESIS was superior to that of SIS.When SIS was changed into ESIS with 15.3% of mass fraction of epoxide groups,Tg of polyisoprene chains increased from-45.3 ℃ to 10.9 ℃.In the earlier period of epoxidation,some molecular chains ruptured and new substances with low molecular weight formed.However,in the latter period,crosslinking reaction between molecular chains which was initiated by epoxide groups or C=C double bonds occurred and crosslinked insoluble substances came into being.展开更多
A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ~ε-caprolactone(CL, B) and glycolide(A) by means of step polymerization in the presence of ethylene glycol as an initiato...A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ~ε-caprolactone(CL, B) and glycolide(A) by means of step polymerization in the presence of ethylene glycol as an initiator and stannous octanoate as a catalyst at 110 ℃ for 48 h. The molecular length of the PCL pre-polymer(BB) could be adjusted by controlling the molar ratio of the ethylene glycol initiator to ε-caprolactone monomer. The structure and the composition of the block copolymer were determined by the weight ratio of the monomer glycolide(A) to PCL pre-polymer(BB). The block copolymers were characterized by ~ 1H NMR, GPC, DSC and X-ray. The results confirm the successful synthesis of an ABBA block copolymer.展开更多
Poly(methyl acrylate)-b-poly(5,6-benzo-2-methylene-1,3-dioxepane) (PMA-b-PBMDO) was synthesized by two-step atom transfer radical polymerization (ATRP). Firstly, ATRP of methyl acrylate (MA) was realized using ethyl a...Poly(methyl acrylate)-b-poly(5,6-benzo-2-methylene-1,3-dioxepane) (PMA-b-PBMDO) was synthesized by two-step atom transfer radical polymerization (ATRP). Firstly, ATRP of methyl acrylate (MA) was realized using ethyl alpha-bromobutyrate (EBrB) as initiator in the presence of CuBr/2,2'-bipyridine. After isolation, poly(methyl acrylate) with terminal bromine (PMA-Br) was synthesized. Secondly, the resulting PMA-Br was used as a macromolecular initiator in the ATRP of BMDO. The structure of block copolymer was characterized by H-1-NMR spectroscopy. Molecular weight and molecular weight distribution were determined on a gel permeation chromatograph (GPC).展开更多
The classical physics theory respectively obeys the three famous conservation laws referred to as charge conjugation, parity and time reverse, and the open pit block model is equal to a Newtonian mechanics system. Con...The classical physics theory respectively obeys the three famous conservation laws referred to as charge conjugation, parity and time reverse, and the open pit block model is equal to a Newtonian mechanics system. Consequently, there would exist some correspondent symmetry principles and conservation laws within the 3D fixed block model of the deposit and the theory for the optimum design of the open pit mine. Reversing a series of relevant fundamental concepts, several conservation laws, which the theory for the optimum design of open pit mines should obey, as block weight conjugation, block model parity and combined symmetry of the both, were expounded. From the symmetry principle, the theoretic significance for a series of the current optimum techniques was discussed and explained, and a kind of conjugate heuristics which can check the error of itself was presented and demonstrated. Thus it is shown that the symmetry principle lays the foundations and opens up the prospects for the further research with mine design and scheduling problem.展开更多
To assess the merits of PEGylated poly （lactic-co-glycolic acid） （PEG-PLGA） nanoparticles as drug carriers for tumor necrosis factor-α receptor blocking peptide （TNFR-BP）, PEG-PLGA copolymer, which could be use...To assess the merits of PEGylated poly （lactic-co-glycolic acid） （PEG-PLGA） nanoparticles as drug carriers for tumor necrosis factor-α receptor blocking peptide （TNFR-BP）, PEG-PLGA copolymer, which could be used to prepare the stealth nanoparticles, was synthesized with methoxypolyethyleneglycol, DL-lactide and glycolide. The structure of PEG-PLGA was confirmed with ^1H-NMR and FT-IR spectroscopy, and the molecular weight （MW） was determined by gel permeation chromatography. Fluorescent FITC-TNFR- BP was chosen as model protein and encapsulated within PEG-PLGA nanoparticles using the double emulsion method. Atomic force microscopy and photon correlation spectroscopy were employed to characterize the stealth nanoparticles fabricated for morphology, size with polydispersity index and zeta potential. Encapsulation efficiency （EE） and the release of FITC-TNFR-BP in nanopartieles in vitro were measured by the fluorescence measurement. The stealth nanoparticles were found to have the mean diameter less than 270 nm and zeta potential less than -20 mV. In all nanoparticle formulations, more than 45% of EE were obtained. FITC-TNFR-BP release from the PEG-PLGA nanoparticles exhibited a biphasic pattern, initial burst release and consequently sustained release. The experimental results show that PEG-PLGA nanoparticles possess the potential to develop as drug carriers for controlled release applications of TNFR-BP.展开更多
文摘In the context of banning gated communities, blocks returning to the human-oriented scale become the new normal, and pedestrian system design will be paid more attention in the urban planning field. Oct-Loft Creative Park is a template for open blocks in Shenzhen, with a convenient and humanized pedestrian system. This paper selects the creative park's pedestrian system as the research object, using the environment-behavior theory for analysis. Finally, optimization strategies of pedestrian system will be put forward.
文摘Epidural analgesia has long been regarded as the gold standard in abdominal surgery. However, concerns regarding risks associated with central neuraxial blockade, catheter placement and the presence of coagulopathy in patients undergoing liver resection have limited its use. Bilateral erector spinae plane blocks and catheter placement may mimic the effects of epidural analgesia by blocking both somatic and visceral pain while concomitantly avoiding central neuraxial blockade and catheter placement. We describe our experience in using the erector spinae plane block and catheter placement as part of a multimodal analgesia approach in a patient undergoing laparoscopic and another patient undergoing open liver resection. Our findings concur with previous reports which suggest that erector spinae plane blocks may be more efficacious as somatic rather than visceral analgesia. However, we conclude that further studies on factors affecting its efficacy should be conducted in view of the present lack of researched evidence.
基金financial support from the National Natural Science Foundation of China (Nos. 21727809, 21635008, 21621062)Chinese Academy of Sciences(No. QYZDJ-SSW-SLH034)
文摘A new open-tubular capillary electrochromatography (OT-CEC) method for analysis of β-lactam antibiotics has been developed with unique block co-polymer coating. To obtain the highly ordered block polymer chains, reversible addition fragmentation chain transfer radical polymerization method was used to synthesize poly (maleic anhydride-styrene-N-isopropylacrylamide). The prepared block copolymer coating was characterized with NMR, fourier transform infrared spectroscopy and scanning electron microscope. Several key separation factors of OT-CEC, which including polymer amount,stability of the coating, temperature, species of organic additives, buffer pH and concentration, were investigated in detail. Our results indicated that the separation efficiency was improved greatly with the coating capillary and the three test analytes could be baseline separated. Then, the separation mechanism was briefly explored. Moreover, the proposed OT-CEC method displayed promising quantitative analysis property of the three test analytes with good linearity (R2>0.99), repeatability (relative standard deviations <0.9%) and high recovery (95.4%-106.2%). Further, the assay was applied in monitoring the three test β-lactam antibiotics (cephradine, cephalexin and amoxicillin) in serum samples, providing a useful platform for construction of novel polymer coatings in OT-CEC system and for analysis of drugs in real bio-samples.
文摘Dysfunction of the cystic fibrosis transmembrane con-ductance regulator(CFTR) chloride channel causes cys-tic fibrosis, while inappropriate activity of this channeloccurs in secretory diarrhea and polycystic kidney dis-ease. Drugs that interact directly with CFTR are there-fore of interest in the treatment of a number of diseasestates. This review focuses on one class of small mol-ecules that interacts directly with CFTR, namely inhibi-tors that act by directly blocking chloride movementthrough the open channel pore. In theory such com-pounds could be of use in the treatment of diarrheaand polycystic kidney disease, however in practice allknown substances acting by this mechanism to inhibitCFTR function lack either the potency or specificity forin vivo use. Nevertheless, this theoretical pharmaco-logical usefulness set the scene for the developmentof more potent, specific CFTR inhibitors. Biophysically,open channel blockers have proven most useful as ex-perimental probes of the structure and function of theCFTR chloride channel pore. Most importantly, the useof these blockers has been fundamental in developing afunctional model of the pore that includes a wide innervestibule that uses positively charged amino acid sidechains to attract both permeant and blocking anionsfrom the cell cytoplasm. CFTR channels are also subjectto this kind of blocking action by endogenous anionspresent in the cell cytoplasm, and recently this blocking effect has been suggested to play a role in the physio-logical control of CFTR channel function, in particular as a novel mechanism linking CFTR function dynamically to the composition of epithelial cell secretions. It has also been suggested that future drugs could target this same pathway as a way of pharmacologically increasing CFTR activity in cystic fibrosis. Studying open channel blockers and their mechanisms of action has resulted in significant advances in our understanding of CFTR as a pharmacological target in disease states, of CFTR chan-nel structure and function, and of how CFTR activity is controlled by its local environment.
基金financially supported by the National Natural Science Foundation of China(Nos.21234006 and 21574098)
文摘A series of cis-5-norbornene-endo-2,3-dicarboxylic anhydride （NDCA, M1） derivatives （M2-M4） with different types of nonpolar substituted groups were synthesized and characterized by 1H/13C-NMR and mass spectrometry （MS）. Ring- opening metathesis polymerization （ROMP） of these monomers using the Grubbs third generation catalyst （G3） generated high molecular weight polymers with much improved solubility compared with the NDCA＇s homopolymer. It was found that the solubility of these polymers increased with increased substituent＇s steric hindrance. The living polymerization of NDCA derivative containing the bulkiest substituent （M4） catalyzed by G3 in tetrahydrofuran was confirmed by the kinetic studies with low polydispersity indices （PDI） （〈 1.30）. By using sequential ROMP, well-defined diblock copolymers containing anhydride groups were synthesized.
文摘Styrene-isoprene-styrene（SIS） block copolymer was modified into epoxidized styrene-isoprene-styrene（ESIS） block copolymer with performic acid generated in situ from hydrogen peroxide and formic acid.The structure and property of ESIS were characterized by Fourier transform infrared（FT-IR） spectroscopy,gel permeation chromatography（GPC）,thermogravimetric/differential thermogravimetric（TG/DTG）,melt flow rate（MFR） and dynamic mechanical analysis（DMA）,and the reaction mechanism in the process of epoxidation was analyzed.The results showed that C=C double bonds of 1,4-structure were more active than that of 3,4-structure in polyisoprene chains.With epoxidation reaction proceeding,the whole tendency of molecular weight increased and molecular weight distribution widened,and MFR firstly increased and latterly decreased.The heat resistance of ESIS was superior to that of SIS.When SIS was changed into ESIS with 15.3% of mass fraction of epoxide groups,Tg of polyisoprene chains increased from-45.3 ℃ to 10.9 ℃.In the earlier period of epoxidation,some molecular chains ruptured and new substances with low molecular weight formed.However,in the latter period,crosslinking reaction between molecular chains which was initiated by epoxide groups or C=C double bonds occurred and crosslinked insoluble substances came into being.
文摘A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ~ε-caprolactone(CL, B) and glycolide(A) by means of step polymerization in the presence of ethylene glycol as an initiator and stannous octanoate as a catalyst at 110 ℃ for 48 h. The molecular length of the PCL pre-polymer(BB) could be adjusted by controlling the molar ratio of the ethylene glycol initiator to ε-caprolactone monomer. The structure and the composition of the block copolymer were determined by the weight ratio of the monomer glycolide(A) to PCL pre-polymer(BB). The block copolymers were characterized by ~ 1H NMR, GPC, DSC and X-ray. The results confirm the successful synthesis of an ABBA block copolymer.
基金This work was supported by the National Natural Science Foundation of China (No. 29774027).
文摘Poly(methyl acrylate)-b-poly(5,6-benzo-2-methylene-1,3-dioxepane) (PMA-b-PBMDO) was synthesized by two-step atom transfer radical polymerization (ATRP). Firstly, ATRP of methyl acrylate (MA) was realized using ethyl alpha-bromobutyrate (EBrB) as initiator in the presence of CuBr/2,2'-bipyridine. After isolation, poly(methyl acrylate) with terminal bromine (PMA-Br) was synthesized. Secondly, the resulting PMA-Br was used as a macromolecular initiator in the ATRP of BMDO. The structure of block copolymer was characterized by H-1-NMR spectroscopy. Molecular weight and molecular weight distribution were determined on a gel permeation chromatograph (GPC).
文摘The classical physics theory respectively obeys the three famous conservation laws referred to as charge conjugation, parity and time reverse, and the open pit block model is equal to a Newtonian mechanics system. Consequently, there would exist some correspondent symmetry principles and conservation laws within the 3D fixed block model of the deposit and the theory for the optimum design of the open pit mine. Reversing a series of relevant fundamental concepts, several conservation laws, which the theory for the optimum design of open pit mines should obey, as block weight conjugation, block model parity and combined symmetry of the both, were expounded. From the symmetry principle, the theoretic significance for a series of the current optimum techniques was discussed and explained, and a kind of conjugate heuristics which can check the error of itself was presented and demonstrated. Thus it is shown that the symmetry principle lays the foundations and opens up the prospects for the further research with mine design and scheduling problem.
基金Funded by the National 863 Project of China (No. 2004AA215162)
文摘To assess the merits of PEGylated poly （lactic-co-glycolic acid） （PEG-PLGA） nanoparticles as drug carriers for tumor necrosis factor-α receptor blocking peptide （TNFR-BP）, PEG-PLGA copolymer, which could be used to prepare the stealth nanoparticles, was synthesized with methoxypolyethyleneglycol, DL-lactide and glycolide. The structure of PEG-PLGA was confirmed with ^1H-NMR and FT-IR spectroscopy, and the molecular weight （MW） was determined by gel permeation chromatography. Fluorescent FITC-TNFR- BP was chosen as model protein and encapsulated within PEG-PLGA nanoparticles using the double emulsion method. Atomic force microscopy and photon correlation spectroscopy were employed to characterize the stealth nanoparticles fabricated for morphology, size with polydispersity index and zeta potential. Encapsulation efficiency （EE） and the release of FITC-TNFR-BP in nanopartieles in vitro were measured by the fluorescence measurement. The stealth nanoparticles were found to have the mean diameter less than 270 nm and zeta potential less than -20 mV. In all nanoparticle formulations, more than 45% of EE were obtained. FITC-TNFR-BP release from the PEG-PLGA nanoparticles exhibited a biphasic pattern, initial burst release and consequently sustained release. The experimental results show that PEG-PLGA nanoparticles possess the potential to develop as drug carriers for controlled release applications of TNFR-BP.
