Background:Sacral pressure ulcers are associated with high morbidity and,in some cases,result in mortality from severe sepsis.Local flaps are frequently used for reconstruction of stage III and IV pressure ulcers.An i...Background:Sacral pressure ulcers are associated with high morbidity and,in some cases,result in mortality from severe sepsis.Local flaps are frequently used for reconstruction of stage III and IV pressure ulcers.An ideal flap should be simple to design,have a reliable vascular supply and minimal donor site morbidity.Our study evaluates the use of a bilobed flap based on the superficial branch of the superior gluteal artery or the posterior branch of the fourth lumbar artery to reconstruct the sacral pressure ulcer.Case presentation:We performed a retrospective analysis of paraplegic patients with sacral pressure ulcers treated with our bilobed flaps from January 2015 to December 2019.A description of our management,operative protocol,outcome and complications is outlined.Seven paraplegic patients(6 male,1 female;average age 53.1 years)with sacral pressure ulcers were treated with our bilobed flap based on the superficial branch of the superior gluteal artery or the posterior branch of the fourth lumbar artery.The average size of the pressure ulcers was 7×5 cm(range 6.2×4.5 cm to 11×10 cm).All 7 flaps survived.The patients were followed up for 12 months without significant complications,such as flap necrosis or recurrence.Conclusions:The superficial branch of the superior gluteal artery or the posterior branch of the fourth lumbar artery reliably supplies the bilobed flap.The superior cluneal nerve can be included in the design.The technique is simple and reliable.It should be included in the reconstructive algorithm for the management of sacral pressure ulcers.展开更多
This paper reports a classical molecular dynamics study of the potential of mean forces(PMFs),association constants,microstructures K^+-Cl^- ion pair in supercritical fluids.The constrained MD method is used to derive...This paper reports a classical molecular dynamics study of the potential of mean forces(PMFs),association constants,microstructures K^+-Cl^- ion pair in supercritical fluids.The constrained MD method is used to derive the PMFs of K^+-Cl^- ion pair from 673 to 1273 K in low-density water(0.10-0.60 g/cm).The PMF results show that the contact ion-pair(CIP) state is the one most energetically favored for a K^+-Cl^- ion pair.The association constants of the K^+-Cl^- ion pair are calculated from the PMFs,indicating that the K^+-Cl^- ion pair is thermodynamically stable.It gets more stable as T increases or water density decreases.The microstructures of the K^+-Cl^- ion pair in the CIP and solvent-shared ion-pair states are characterized in detail.Moreover,we explore the structures and stabilities of the KCl-Au(I)/Cu(I) complexes by using quantum mechanical calculations.The results reveal that these complexes can remain stable for T up to1273 K,which indicates that KCl may act as a ligand complexing ore-forming metals in hydrothermal fluids.展开更多
Magmatic-hydrothermal processes play an important role in the transport, enrichment, and mineralization of cesium. In this study, classical molecular dynamics simulations were performed to investigate the properties o...Magmatic-hydrothermal processes play an important role in the transport, enrichment, and mineralization of cesium. In this study, classical molecular dynamics simulations were performed to investigate the properties of Cs-Cl and Cs-F ion pairs in hydrothermal fluids. The association constants(log_(10)K_(A)(m)) under a wide range of temperature(i.e. 298–1273 K) and fluid density(i.e. 0.1–1.0 g/cm^(3)) were derived from the potential of mean force(PMF) curves. The results indicate that CsCl and Cs-F ion pairs have similar stabilities. This is different from other alkali metal cations(e.g., Li^(+), Na^(+), and K^(+)), which prefer binding with F over Cl. The stabilities of Cs-Cl and Cs-F ion pairs increase with increasing temperature(except for the fluid density ≤ 0.1 g/cm^(3)) or decreasing fluid density, which is similar to other alkali halide ion pairs. Comparisons among the stabilities of CsCl/F and other alkali halide ion pairs indicate that the Li–F ion pair has the highest stability in hydrothermal fluids.展开更多
We use molecular dynamics simulation to study the mechanisms involved in the adsorption of aqueous uranyl species(UO_2^(2+)) to the basal surfaces of clay minerals,including kaolinite,pyrophyllite and montmorillonite....We use molecular dynamics simulation to study the mechanisms involved in the adsorption of aqueous uranyl species(UO_2^(2+)) to the basal surfaces of clay minerals,including kaolinite,pyrophyllite and montmorillonite.Uranyl ion can form various complexes with carbonates,namely,[UO_2(H_2O)_5]^(2+),[UO_2(H_2O)3(CO_3)],[UO_2(H_2O)2(CO_3)_2]^(2-),[UO_2(CO_3)_3]^(4-).The simulations show that at aqueous clay interfaces,both uranyl species and surface type control the adsorption pattern.The noncarbonato and monocarbonato uranyl species can form outer-sphere complexes on siloxane surfaces through electrostatic interaction,but the dicarbonato and tricarbonato uranyl complexes rarely adsorb on the siloxane surfaces.Strong outer-sphere adsorptions of the uranylcarbonate complexes on gibbsite surfaces are observed,which are fixed by hydrogen bonds between the ligands(carbonate and/or H_2O) and surface hydroxyls.The sorption behaviors derived in this study provide new insights into understanding the migration and enrichment of uranium and other radionuclides.展开更多
基金supported by funding from the following programs:The National Natural Science Foundation of China(Grant Number:81772098)the Clinical Multi-Disciplinary Team Research Program of the Ninth People’s Hospital,Shanghai Jiao Tong University School of Medicine+1 种基金the Clinical Research Program of the Ninth People’s Hospital,Shanghai Jiao Tong University School of Medicineand the Shanghai Municipal Education Commission Gaofeng Clinical Medicine Grant Support.
文摘Background:Sacral pressure ulcers are associated with high morbidity and,in some cases,result in mortality from severe sepsis.Local flaps are frequently used for reconstruction of stage III and IV pressure ulcers.An ideal flap should be simple to design,have a reliable vascular supply and minimal donor site morbidity.Our study evaluates the use of a bilobed flap based on the superficial branch of the superior gluteal artery or the posterior branch of the fourth lumbar artery to reconstruct the sacral pressure ulcer.Case presentation:We performed a retrospective analysis of paraplegic patients with sacral pressure ulcers treated with our bilobed flaps from January 2015 to December 2019.A description of our management,operative protocol,outcome and complications is outlined.Seven paraplegic patients(6 male,1 female;average age 53.1 years)with sacral pressure ulcers were treated with our bilobed flap based on the superficial branch of the superior gluteal artery or the posterior branch of the fourth lumbar artery.The average size of the pressure ulcers was 7×5 cm(range 6.2×4.5 cm to 11×10 cm).All 7 flaps survived.The patients were followed up for 12 months without significant complications,such as flap necrosis or recurrence.Conclusions:The superficial branch of the superior gluteal artery or the posterior branch of the fourth lumbar artery reliably supplies the bilobed flap.The superior cluneal nerve can be included in the design.The technique is simple and reliable.It should be included in the reconstructive algorithm for the management of sacral pressure ulcers.
基金National Science Foundation of China(Nos.41222015,41273074,41425009,and 41572027)Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase)+1 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of P.R.China (No.201228)Newton International Fellowship Program and the financial support from the State Key Laboratory at Nanjing University
文摘This paper reports a classical molecular dynamics study of the potential of mean forces(PMFs),association constants,microstructures K^+-Cl^- ion pair in supercritical fluids.The constrained MD method is used to derive the PMFs of K^+-Cl^- ion pair from 673 to 1273 K in low-density water(0.10-0.60 g/cm).The PMF results show that the contact ion-pair(CIP) state is the one most energetically favored for a K^+-Cl^- ion pair.The association constants of the K^+-Cl^- ion pair are calculated from the PMFs,indicating that the K^+-Cl^- ion pair is thermodynamically stable.It gets more stable as T increases or water density decreases.The microstructures of the K^+-Cl^- ion pair in the CIP and solvent-shared ion-pair states are characterized in detail.Moreover,we explore the structures and stabilities of the KCl-Au(I)/Cu(I) complexes by using quantum mechanical calculations.The results reveal that these complexes can remain stable for T up to1273 K,which indicates that KCl may act as a ligand complexing ore-forming metals in hydrothermal fluids.
基金supported by the National Natural Science Foundation of China (Nos 92062213,91855209,42125202 and 41872041)the financial support from the State Key Laboratory for Mineral Deposits Research at Nanjing University。
文摘Magmatic-hydrothermal processes play an important role in the transport, enrichment, and mineralization of cesium. In this study, classical molecular dynamics simulations were performed to investigate the properties of Cs-Cl and Cs-F ion pairs in hydrothermal fluids. The association constants(log_(10)K_(A)(m)) under a wide range of temperature(i.e. 298–1273 K) and fluid density(i.e. 0.1–1.0 g/cm^(3)) were derived from the potential of mean force(PMF) curves. The results indicate that CsCl and Cs-F ion pairs have similar stabilities. This is different from other alkali metal cations(e.g., Li^(+), Na^(+), and K^(+)), which prefer binding with F over Cl. The stabilities of Cs-Cl and Cs-F ion pairs increase with increasing temperature(except for the fluid density ≤ 0.1 g/cm^(3)) or decreasing fluid density, which is similar to other alkali halide ion pairs. Comparisons among the stabilities of CsCl/F and other alkali halide ion pairs indicate that the Li–F ion pair has the highest stability in hydrothermal fluids.
基金National Science Foundation of China(Nos.41002013,40973029,41273074 and 41222015)the Foundation for the Author of National Excellent Doctoral Dissertation of PR China(No.201228)+1 种基金Newton International Fellowship Programthe financial support from the State Key Laboratory for Mineral Deposits Research
文摘We use molecular dynamics simulation to study the mechanisms involved in the adsorption of aqueous uranyl species(UO_2^(2+)) to the basal surfaces of clay minerals,including kaolinite,pyrophyllite and montmorillonite.Uranyl ion can form various complexes with carbonates,namely,[UO_2(H_2O)_5]^(2+),[UO_2(H_2O)3(CO_3)],[UO_2(H_2O)2(CO_3)_2]^(2-),[UO_2(CO_3)_3]^(4-).The simulations show that at aqueous clay interfaces,both uranyl species and surface type control the adsorption pattern.The noncarbonato and monocarbonato uranyl species can form outer-sphere complexes on siloxane surfaces through electrostatic interaction,but the dicarbonato and tricarbonato uranyl complexes rarely adsorb on the siloxane surfaces.Strong outer-sphere adsorptions of the uranylcarbonate complexes on gibbsite surfaces are observed,which are fixed by hydrogen bonds between the ligands(carbonate and/or H_2O) and surface hydroxyls.The sorption behaviors derived in this study provide new insights into understanding the migration and enrichment of uranium and other radionuclides.
