Sugar aminotransferases(SATs)catalyze the installation of chiral amines onto specific keto sugars,pro-ducing bioactive amino sugars.Their activity has been utilized in artificial reactions,such as using the SAT WecE t...Sugar aminotransferases(SATs)catalyze the installation of chiral amines onto specific keto sugars,pro-ducing bioactive amino sugars.Their activity has been utilized in artificial reactions,such as using the SAT WecE to transform valienone into the valuable a-glucosidase inhibitor valienamine.However,the low thermostability and limited activity on non-natural substrates have hindered their applications.Simultaneously improving stability and enzyme activity is particularly challenging owing to the acknowledged inherent trade-off between stability and activity.A customized combinatorial active-site saturation test-iterative saturation mutagenesis(CAST-ISM)strategy was used to simultaneously enhance the stability and activity of WecE toward valienone.Fourteen hotspots related to improving the stability-\activity trade-off were identified based on evolutionary conservation and the average mutation folding energy assessment of 57 residues in the active site of WecE.Positive mutagenesis and combinatorial mutations of these specific residues were accomplished via site-directed saturation mutagenesis(SSM)and iterative evolution cycles.Compared with those of the wild-type(WT)WecE,the quadruple mutant M4(Y321F/K209F/V318R/F319V)displayed a 641.49-fold increase in half-life(t_(1/2))at 40℃ and a 31.37-fold increase in activity toward the non-natural substrate valienone.The tri-ple mutant M3(Y321F/K209F/V318R)demonstrated an 83.04-fold increase in(t_(1/2))at 40℃and a 37.77-fold increase in activity toward valienone.The underlying mechanism was dependent on the strengthened interface interactions and shortened transamination reaction catalytic distance,compared with those of the WT,which improved the stability and activity of the obtained mutants.Thus,we accomplished a general target-oriented strategy for obtaining stable and highly active SATs for artificial amino-sugar biosynthesis applications.展开更多
The Benefits Approach to Leisure (BAL), recognized as a major and badly needed "paradigm shift" in the way we conceive of and manage recreation resources, is believed to play a big role in achieving the sust...The Benefits Approach to Leisure (BAL), recognized as a major and badly needed "paradigm shift" in the way we conceive of and manage recreation resources, is believed to play a big role in achieving the sustainable development of tourism industry. BAL has been proved to be effective and efficient in the field of leisure and tourism in terms of its three types of benefits and two stages of production. This paper, using Aqua Zoo in Friesland, the Netherlands as a case, investigates the significance of BAL to the sustainable tourism development.展开更多
The CRISPR/Cas9 mediates efficient gene editing but has off-target effects inconducive to animal breeding. In this study, the efficacy of CRISPR/Cas9 vectors containing different lengths of g RNA in reduction of the o...The CRISPR/Cas9 mediates efficient gene editing but has off-target effects inconducive to animal breeding. In this study, the efficacy of CRISPR/Cas9 vectors containing different lengths of g RNA in reduction of the off-target phenomenon in the bovine MSTN gene knockout fibroblast cell lines was assessed, providing insight into improved methods for livestock breeding. A 20-bp g RNA was designed for the second exon of the bovine MSTN gene, and CRISPR/Cas9-B was constructed to guide the Cas9 protein to the AGAACCAGGAGAAGATGGACTGG site. The alternative CRISPR/Cas9-19, CRISPR/Cas9-18, CRISPR/Cas9-17 and CRISPR/Cas9-15 vectors were constructed using g RNAs truncated by 1, 2, 3 and 5 bp, respectively. These vectors were then introduced into bovine fetal fibroblasts by the electroporation method, and single cells were obtained by flow cytometry sorting. PCR was performed for each off-target site. All samples were sequenced and analyzed, and finally the efficiency of each vector in target and off-target sites was compared. The CRISPR/Cas9-B vector successfully knocked out the MSTN gene, but the off-target phenomenon was observed. The efficiencies of CRISPR/Cas-B, CRISPR/Cas9-19, CRISPR/Cas9-18, CRISPR/Cas9-17 and CRISPR/Cas9-15 in triggering gene mutations at MSTN targeting sites were 62.16, 17.39, 7.69, 74.29 and 3.85%, respectively;rates of each at the Off-MSTN-1 locus were 52.86, 0, 0, 8.82 and 0%, respectively;all were 0% at the Off-MSTN-2 locus;rates at the Off-MSTN-3 site were 44.87, 51.72, 86.36, 0 and 50%, respectively. The efficiency of the CRISPR/Cas9-17 plasmid in the MSTN site was higher than that in the CRISPR/Cas9-B plasmid, and the effect at the three off-target sites was significantly lower. This study demonstrated that the CRISPR/Cas9-17 plasmid constructed by truncating 3 bp g RNA can effectively reduce the off-target effect without reducing the efficiency of bovine MSTN gene targeting. This finding will provide more effective gene editing strategy for use of CRISPR/Cas9 technology.展开更多
On-site maintenance(ONSM) is critical to ensuring the safety of equipment in the petrochemical industry. However, many accidents occur during ONSM processes because of unstable equipment, complicated work environment,...On-site maintenance(ONSM) is critical to ensuring the safety of equipment in the petrochemical industry. However, many accidents occur during ONSM processes because of unstable equipment, complicated work environment, and human error. To reduce congestion and exposure to hazards during on-site operations and thereby reduce the probability of accidents, off-site maintenance(OFSM) is proposed based on Energy Release Theory(ERT). The information requirements for OFSM are analyzed. A support system for OFSM, which makes use of visualization, information management, and localization capabilities, is developed. A case study utilizing OFSM and its support system for an oil-loading facility of a petrochemical company is conducted. The application results indicated that implementation of OFSM system can significantly reduce the operation risks and can improve the operation efficiency.展开更多
In recent years,the problem of“Impolite Pedestrian”in front of the zebra crossing has aroused widespread concern from all walks of life.The traffic sector’s governance measures have become more serious.The traditio...In recent years,the problem of“Impolite Pedestrian”in front of the zebra crossing has aroused widespread concern from all walks of life.The traffic sector’s governance measures have become more serious.The traditional way of governance is on-site law enforcement,which requires a lot of manpower and material resources and is low efficiency.An enhanced YOLOv3-tiny model is proposed for pedestrians and vehicle detection in traffic monitoring.By modifying the backbone network structure of YOLOv3-tiny model,introducing deep detachable convolution operation,and designing the basic residual block unit of the network,the feature extraction ability of the backbone network is enhanced.The improved model is trained on the VOC2007+VOC2012 training set,and the trained model is tested for performance on the test data set.The experimental results show that:the mean Average Precision(mAP)increased from 0.672 to 0.732,increasing the measurement accuracy by 9%.The Intersection over Union(IoU)increased from 0.783 to 0.855,increasing the coverage accuracy by 7.2%.The enhanced YOLOv3-tiny model has higher measurement accuracy than the original model.Applying this model to the 1080P traffic video on the NVIDIA RTX 2080,the detection speed is 150 FPS,which can fully achieve real-time detection.Through the analysis of pedestrians and vehicle coordinates,it is judged whether or not illegal acts occur.For illegal vehicles,save three pictures as the basis for law enforcement,which forms an important supplement to off-site law enforcement.展开更多
Background: Academic anesthesia departments are under increasing financial pressure. Many struggle to integrate the priorities of their academic and clinical missions. Previous studies have documented increasing need ...Background: Academic anesthesia departments are under increasing financial pressure. Many struggle to integrate the priorities of their academic and clinical missions. Previous studies have documented increasing need for monetary institutional support of academic anesthesia departments. In view of current economic and legislative circumstances, it is arguable that the need for support will grow. This survey demonstrates that staffing issues, which are most likely engendered by financial circumstances, have impacted academic anesthesia departments in the United States to the point of having deleterious effects upon clinical safety and resident education.Methods: After IRB approval, we electronically solicited the anonymous response to a 23 question survey from all 133 chairpersons of academic anesthesia departments in the United States. Results: Sixty-two responded electronically, for an overall response rate of 46.6%. Conclusion: The results of this survey suggest that academic anesthesia departments are being financially stressed to the point that education and patient care are affected.展开更多
The Bose-Hubbard model with an effective off-site three-body tunneling,characterized by jumps towards one another,between one atom on a site and a pair atoms on the neighborhood site,is studied systematically on a one...The Bose-Hubbard model with an effective off-site three-body tunneling,characterized by jumps towards one another,between one atom on a site and a pair atoms on the neighborhood site,is studied systematically on a one-dimensional（1D） lattice,by using the density matrix renormalization group method.The off-site trimer superfluid,condensing at momentum k = 0,emerges in the softcore Bose-Hubbard model but it disappears in the hardcore Bose-Hubbard model.Our results numerically verify that the off-site trimer superfluid phase derived in the momentum space from[Phys.Rev.A81,011601（R）（2010）]is stable in the thermodynamic limit.The off-site trimer superfluid phase,the partially off-site trimer superfluid phase and the Mott insulator phase are found,as well as interesting phase transitions,such as the continuous or first-order phase transition from the trimer superfluid phase to the Mott insulator phase.Our results are helpful in realizing this novel off-site trimer superfluid phase by cold atom experiments.展开更多
We perform a variational Monte Carlo study of the nematic state in iron-pnictide superconductors within a realistic five-orbital model. Our numerical results show that the nematic state, formed by introducing an aniso...We perform a variational Monte Carlo study of the nematic state in iron-pnictide superconductors within a realistic five-orbital model. Our numerical results show that the nematic state, formed by introducing an anisotropic hopping order into the projected wave function, is not stable unless the off-site Coulomb interaction V exceeds a critical value. This demonstrates that V plays a key role in forming the nematic state in iron-pnictide superconductors. In the nematic state,the orbital order and the anisotropic spin correlations are consistent with the experimental observations. We argue that the experimentally observed anisotropic magnetic couplings and structural transition are associated with the nematic state and can be understood in a unified framework.展开更多
The objective of this study was to describe our NICU’s (neonatal intensive care unit) experience with mobile surgical team and to demonstrate its effectiveness. Method: We analyzed the data of 17 consecutive very low...The objective of this study was to describe our NICU’s (neonatal intensive care unit) experience with mobile surgical team and to demonstrate its effectiveness. Method: We analyzed the data of 17 consecutive very low birth weight and extremely low birth weight infants over 3 years who underwent 22 procedures (19 emergency and 3 elective). The gestational age at birth was a median of 25 weeks (range 24 - 39), and the median birth weight was 613 g (range from 340 g to 1100 g). The infants received their operations during their first 2 weeks of life (median 7 days, range from 1 to 14). Results: The spectrum of primary surgical diagnoses included spontaneous intestinal perforations (n = 8), gastric perforations (n = 3), necrotizing enterocolitis (n = 2), meconium ileus (n = 2), and miscellaneous (n = 2). An emergency laparotomy with either a bowel or a gastric procedure was performed in 16 cases. Postoperatively, all infants required mechanical ventilation from 1 to 43 days (median 6.5 days). Complications included a metachronous small bowel perforation, an ileostomy retraction, a prolapsed stoma, and impaired wound healing;we had one postoperative death. Two infants died later in the NICU (mortality 3 of 16;19%). Conclusion: Off-site surgery for preterm infants in the NICU is feasible. This approach prevents the risks of transportation, and parents and neonatologists alike feel comfortable with this regimen. However, biases may exist regarding the surgeon’s decision to operate, the choice of procedure, and the follow-up.展开更多
Stakeholders remain skeptical in adopting modular integrated construction(MiC)because of the associated risks and uncertainties,although its benefits have been extensively documented.The unique business model of MiC n...Stakeholders remain skeptical in adopting modular integrated construction(MiC)because of the associated risks and uncertainties,although its benefits have been extensively documented.The unique business model of MiC nurtures several risks and uncertainties different from those of the conventional construction approach.Despite the growing attention on MiC with its market expansion,no systematic evaluation is in place to monitor its risks research progress.Accordingly,this research reviewed published literature addressing the risks associated with MiC from 1992 to 2019.Analysis reveals that the research publications on risks of MiC witnessed a steady growth,with considerable progress occurring in the last decade.Result implies that the risk of MiC has gained extra attention in the construction engineering and management domain in recent times.Existing empirical studies have focused heavily on perceived implementation risks,supply chain risks,schedule risks,investment risks,structural risks,ergonomic risks,and MiC risk management strategies,which indicate that MiC is associated with a host of risk events.The research further identified the critical risk events(CREs)in the application of MiC based on frequency of occurrence.The identified CREs contributes to the checklists of risk events in the implementation of offsite construction(OSC).The latter may be useful in risk planning,especially where the MiC is less developed,and fewer or no bespoke risk assessment exists.Research gaps in existing studies are highlighted in this research,and areas for further studies are then proposed.Thus,it makes a useful contribution to the scholarly literature on the risk of OSC and may prove useful to offsite construction researchers,industry practitioners,and project managers.展开更多
对OFF沸石进行离子交换,制备出NH4-OFF沸石,然后通过Li2CO3/NH4-OFF体系的固态反应制备了不同锂离子交换度的Li-OFF沸石.对吸附氮气和氧气的Li-OFF样品进行了7Li MAS NMR表征,结果表明,所有吸附氧气样品的部分7Li MAS NMR共振峰均发生...对OFF沸石进行离子交换,制备出NH4-OFF沸石,然后通过Li2CO3/NH4-OFF体系的固态反应制备了不同锂离子交换度的Li-OFF沸石.对吸附氮气和氧气的Li-OFF样品进行了7Li MAS NMR表征,结果表明,所有吸附氧气样品的部分7Li MAS NMR共振峰均发生了顺磁位移.通过对实验谱的拟合,得知Li-OFF沸石中的锂离子可分布在3类阳离子位置(A,B和C)上,对应于3个不同位移的谱峰.Li+离子并非等比例地进入3类可交换的位置,而是优先占据主孔道中的A位置,随着交换度的升高,位能较高的C和B位置上的Li离子占有率逐渐增加.在100%固态交换度样品中,Li+离子在不同离子位的占有率分别为17%(位置B),29%(位置C)和54%(位置A).其中,位置B是O2分子不可接近的,所以Li-OFF沸石中有83%的阳离子是可以接近的.展开更多
Housing must be flexible to the circumstances growing families face as their needs change during the family lifecycle.The purpose of this paper is to gather a prelimi-nary understanding of growing families’needs and ...Housing must be flexible to the circumstances growing families face as their needs change during the family lifecycle.The purpose of this paper is to gather a prelimi-nary understanding of growing families’needs and evaluate how modular off-site manufactured construction could effectively answer those needs.Despite the large amount of research that has gone into off-site manufactured buildings,there is little research that has explored its suitability as a flexible housing typology for growing families.The pilot presented in this paper investigates the specific context of Bris-bane,Australia;qualitative data have been gathered from growing families in this city and combined with established theory on flexible building to develop a pre-liminary understanding of how modular off-site manufactured construction could perform in meeting flexibility requirements in comparison to a traditional light-weight timber framed construction.Findings highlight how the ability to modify a dwelling is a fundamental feature for growing families;a number of other advan-tages in flexibility were found in modular off-site manufacture and recommenda-tions made to improve this construction typology.展开更多
基金supported by the National Key Research and Development Program of China(2018YFE0200501 and 2020YFA0907700)the National Natural Science Foundation of China(32271306 and 21977067).
文摘Sugar aminotransferases(SATs)catalyze the installation of chiral amines onto specific keto sugars,pro-ducing bioactive amino sugars.Their activity has been utilized in artificial reactions,such as using the SAT WecE to transform valienone into the valuable a-glucosidase inhibitor valienamine.However,the low thermostability and limited activity on non-natural substrates have hindered their applications.Simultaneously improving stability and enzyme activity is particularly challenging owing to the acknowledged inherent trade-off between stability and activity.A customized combinatorial active-site saturation test-iterative saturation mutagenesis(CAST-ISM)strategy was used to simultaneously enhance the stability and activity of WecE toward valienone.Fourteen hotspots related to improving the stability-\activity trade-off were identified based on evolutionary conservation and the average mutation folding energy assessment of 57 residues in the active site of WecE.Positive mutagenesis and combinatorial mutations of these specific residues were accomplished via site-directed saturation mutagenesis(SSM)and iterative evolution cycles.Compared with those of the wild-type(WT)WecE,the quadruple mutant M4(Y321F/K209F/V318R/F319V)displayed a 641.49-fold increase in half-life(t_(1/2))at 40℃ and a 31.37-fold increase in activity toward the non-natural substrate valienone.The tri-ple mutant M3(Y321F/K209F/V318R)demonstrated an 83.04-fold increase in(t_(1/2))at 40℃and a 37.77-fold increase in activity toward valienone.The underlying mechanism was dependent on the strengthened interface interactions and shortened transamination reaction catalytic distance,compared with those of the WT,which improved the stability and activity of the obtained mutants.Thus,we accomplished a general target-oriented strategy for obtaining stable and highly active SATs for artificial amino-sugar biosynthesis applications.
文摘The Benefits Approach to Leisure (BAL), recognized as a major and badly needed "paradigm shift" in the way we conceive of and manage recreation resources, is believed to play a big role in achieving the sustainable development of tourism industry. BAL has been proved to be effective and efficient in the field of leisure and tourism in terms of its three types of benefits and two stages of production. This paper, using Aqua Zoo in Friesland, the Netherlands as a case, investigates the significance of BAL to the sustainable tourism development.
基金supported by the National Transgenic Project of China (2016ZX08010001-002 and 2016ZX08010005-001)the National Natural Science Foundation of China (81471001)the Inner Mongolia Science and Technology Program, China (201502073)
文摘The CRISPR/Cas9 mediates efficient gene editing but has off-target effects inconducive to animal breeding. In this study, the efficacy of CRISPR/Cas9 vectors containing different lengths of g RNA in reduction of the off-target phenomenon in the bovine MSTN gene knockout fibroblast cell lines was assessed, providing insight into improved methods for livestock breeding. A 20-bp g RNA was designed for the second exon of the bovine MSTN gene, and CRISPR/Cas9-B was constructed to guide the Cas9 protein to the AGAACCAGGAGAAGATGGACTGG site. The alternative CRISPR/Cas9-19, CRISPR/Cas9-18, CRISPR/Cas9-17 and CRISPR/Cas9-15 vectors were constructed using g RNAs truncated by 1, 2, 3 and 5 bp, respectively. These vectors were then introduced into bovine fetal fibroblasts by the electroporation method, and single cells were obtained by flow cytometry sorting. PCR was performed for each off-target site. All samples were sequenced and analyzed, and finally the efficiency of each vector in target and off-target sites was compared. The CRISPR/Cas9-B vector successfully knocked out the MSTN gene, but the off-target phenomenon was observed. The efficiencies of CRISPR/Cas-B, CRISPR/Cas9-19, CRISPR/Cas9-18, CRISPR/Cas9-17 and CRISPR/Cas9-15 in triggering gene mutations at MSTN targeting sites were 62.16, 17.39, 7.69, 74.29 and 3.85%, respectively;rates of each at the Off-MSTN-1 locus were 52.86, 0, 0, 8.82 and 0%, respectively;all were 0% at the Off-MSTN-2 locus;rates at the Off-MSTN-3 site were 44.87, 51.72, 86.36, 0 and 50%, respectively. The efficiency of the CRISPR/Cas9-17 plasmid in the MSTN site was higher than that in the CRISPR/Cas9-B plasmid, and the effect at the three off-target sites was significantly lower. This study demonstrated that the CRISPR/Cas9-17 plasmid constructed by truncating 3 bp g RNA can effectively reduce the off-target effect without reducing the efficiency of bovine MSTN gene targeting. This finding will provide more effective gene editing strategy for use of CRISPR/Cas9 technology.
文摘On-site maintenance(ONSM) is critical to ensuring the safety of equipment in the petrochemical industry. However, many accidents occur during ONSM processes because of unstable equipment, complicated work environment, and human error. To reduce congestion and exposure to hazards during on-site operations and thereby reduce the probability of accidents, off-site maintenance(OFSM) is proposed based on Energy Release Theory(ERT). The information requirements for OFSM are analyzed. A support system for OFSM, which makes use of visualization, information management, and localization capabilities, is developed. A case study utilizing OFSM and its support system for an oil-loading facility of a petrochemical company is conducted. The application results indicated that implementation of OFSM system can significantly reduce the operation risks and can improve the operation efficiency.
基金supported by the following funds:National Key R&D Program of China(2018YFF01010100)National natural science foundation of China(61672064)+1 种基金Beijing natural science foundation project(4172001)Advanced information network Beijing laboratory(PXM2019_014204_500029).
文摘In recent years,the problem of“Impolite Pedestrian”in front of the zebra crossing has aroused widespread concern from all walks of life.The traffic sector’s governance measures have become more serious.The traditional way of governance is on-site law enforcement,which requires a lot of manpower and material resources and is low efficiency.An enhanced YOLOv3-tiny model is proposed for pedestrians and vehicle detection in traffic monitoring.By modifying the backbone network structure of YOLOv3-tiny model,introducing deep detachable convolution operation,and designing the basic residual block unit of the network,the feature extraction ability of the backbone network is enhanced.The improved model is trained on the VOC2007+VOC2012 training set,and the trained model is tested for performance on the test data set.The experimental results show that:the mean Average Precision(mAP)increased from 0.672 to 0.732,increasing the measurement accuracy by 9%.The Intersection over Union(IoU)increased from 0.783 to 0.855,increasing the coverage accuracy by 7.2%.The enhanced YOLOv3-tiny model has higher measurement accuracy than the original model.Applying this model to the 1080P traffic video on the NVIDIA RTX 2080,the detection speed is 150 FPS,which can fully achieve real-time detection.Through the analysis of pedestrians and vehicle coordinates,it is judged whether or not illegal acts occur.For illegal vehicles,save three pictures as the basis for law enforcement,which forms an important supplement to off-site law enforcement.
文摘Background: Academic anesthesia departments are under increasing financial pressure. Many struggle to integrate the priorities of their academic and clinical missions. Previous studies have documented increasing need for monetary institutional support of academic anesthesia departments. In view of current economic and legislative circumstances, it is arguable that the need for support will grow. This survey demonstrates that staffing issues, which are most likely engendered by financial circumstances, have impacted academic anesthesia departments in the United States to the point of having deleterious effects upon clinical safety and resident education.Methods: After IRB approval, we electronically solicited the anonymous response to a 23 question survey from all 133 chairpersons of academic anesthesia departments in the United States. Results: Sixty-two responded electronically, for an overall response rate of 46.6%. Conclusion: The results of this survey suggest that academic anesthesia departments are being financially stressed to the point that education and patient care are affected.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11305113)the Project GDW201400042 for the“High End Foreign Experts Program”
文摘The Bose-Hubbard model with an effective off-site three-body tunneling,characterized by jumps towards one another,between one atom on a site and a pair atoms on the neighborhood site,is studied systematically on a one-dimensional（1D） lattice,by using the density matrix renormalization group method.The off-site trimer superfluid,condensing at momentum k = 0,emerges in the softcore Bose-Hubbard model but it disappears in the hardcore Bose-Hubbard model.Our results numerically verify that the off-site trimer superfluid phase derived in the momentum space from[Phys.Rev.A81,011601（R）（2010）]is stable in the thermodynamic limit.The off-site trimer superfluid phase,the partially off-site trimer superfluid phase and the Mott insulator phase are found,as well as interesting phase transitions,such as the continuous or first-order phase transition from the trimer superfluid phase to the Mott insulator phase.Our results are helpful in realizing this novel off-site trimer superfluid phase by cold atom experiments.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11274310,11474287,11174072,and 91221103)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20104208110001)
文摘We perform a variational Monte Carlo study of the nematic state in iron-pnictide superconductors within a realistic five-orbital model. Our numerical results show that the nematic state, formed by introducing an anisotropic hopping order into the projected wave function, is not stable unless the off-site Coulomb interaction V exceeds a critical value. This demonstrates that V plays a key role in forming the nematic state in iron-pnictide superconductors. In the nematic state,the orbital order and the anisotropic spin correlations are consistent with the experimental observations. We argue that the experimentally observed anisotropic magnetic couplings and structural transition are associated with the nematic state and can be understood in a unified framework.
文摘The objective of this study was to describe our NICU’s (neonatal intensive care unit) experience with mobile surgical team and to demonstrate its effectiveness. Method: We analyzed the data of 17 consecutive very low birth weight and extremely low birth weight infants over 3 years who underwent 22 procedures (19 emergency and 3 elective). The gestational age at birth was a median of 25 weeks (range 24 - 39), and the median birth weight was 613 g (range from 340 g to 1100 g). The infants received their operations during their first 2 weeks of life (median 7 days, range from 1 to 14). Results: The spectrum of primary surgical diagnoses included spontaneous intestinal perforations (n = 8), gastric perforations (n = 3), necrotizing enterocolitis (n = 2), meconium ileus (n = 2), and miscellaneous (n = 2). An emergency laparotomy with either a bowel or a gastric procedure was performed in 16 cases. Postoperatively, all infants required mechanical ventilation from 1 to 43 days (median 6.5 days). Complications included a metachronous small bowel perforation, an ileostomy retraction, a prolapsed stoma, and impaired wound healing;we had one postoperative death. Two infants died later in the NICU (mortality 3 of 16;19%). Conclusion: Off-site surgery for preterm infants in the NICU is feasible. This approach prevents the risks of transportation, and parents and neonatologists alike feel comfortable with this regimen. However, biases may exist regarding the surgeon’s decision to operate, the choice of procedure, and the follow-up.
基金This paper was fully funded under the Hong Kong Ph.D.Fellowship Scheme(HKPFS:PF17-00649)by the Research Grants Council of the Hong Kong Special Administrative Region,China.
文摘Stakeholders remain skeptical in adopting modular integrated construction(MiC)because of the associated risks and uncertainties,although its benefits have been extensively documented.The unique business model of MiC nurtures several risks and uncertainties different from those of the conventional construction approach.Despite the growing attention on MiC with its market expansion,no systematic evaluation is in place to monitor its risks research progress.Accordingly,this research reviewed published literature addressing the risks associated with MiC from 1992 to 2019.Analysis reveals that the research publications on risks of MiC witnessed a steady growth,with considerable progress occurring in the last decade.Result implies that the risk of MiC has gained extra attention in the construction engineering and management domain in recent times.Existing empirical studies have focused heavily on perceived implementation risks,supply chain risks,schedule risks,investment risks,structural risks,ergonomic risks,and MiC risk management strategies,which indicate that MiC is associated with a host of risk events.The research further identified the critical risk events(CREs)in the application of MiC based on frequency of occurrence.The identified CREs contributes to the checklists of risk events in the implementation of offsite construction(OSC).The latter may be useful in risk planning,especially where the MiC is less developed,and fewer or no bespoke risk assessment exists.Research gaps in existing studies are highlighted in this research,and areas for further studies are then proposed.Thus,it makes a useful contribution to the scholarly literature on the risk of OSC and may prove useful to offsite construction researchers,industry practitioners,and project managers.
文摘对OFF沸石进行离子交换,制备出NH4-OFF沸石,然后通过Li2CO3/NH4-OFF体系的固态反应制备了不同锂离子交换度的Li-OFF沸石.对吸附氮气和氧气的Li-OFF样品进行了7Li MAS NMR表征,结果表明,所有吸附氧气样品的部分7Li MAS NMR共振峰均发生了顺磁位移.通过对实验谱的拟合,得知Li-OFF沸石中的锂离子可分布在3类阳离子位置(A,B和C)上,对应于3个不同位移的谱峰.Li+离子并非等比例地进入3类可交换的位置,而是优先占据主孔道中的A位置,随着交换度的升高,位能较高的C和B位置上的Li离子占有率逐渐增加.在100%固态交换度样品中,Li+离子在不同离子位的占有率分别为17%(位置B),29%(位置C)和54%(位置A).其中,位置B是O2分子不可接近的,所以Li-OFF沸石中有83%的阳离子是可以接近的.
文摘Housing must be flexible to the circumstances growing families face as their needs change during the family lifecycle.The purpose of this paper is to gather a prelimi-nary understanding of growing families’needs and evaluate how modular off-site manufactured construction could effectively answer those needs.Despite the large amount of research that has gone into off-site manufactured buildings,there is little research that has explored its suitability as a flexible housing typology for growing families.The pilot presented in this paper investigates the specific context of Bris-bane,Australia;qualitative data have been gathered from growing families in this city and combined with established theory on flexible building to develop a pre-liminary understanding of how modular off-site manufactured construction could perform in meeting flexibility requirements in comparison to a traditional light-weight timber framed construction.Findings highlight how the ability to modify a dwelling is a fundamental feature for growing families;a number of other advan-tages in flexibility were found in modular off-site manufacture and recommenda-tions made to improve this construction typology.
