Tetra-hydroxymethyl phosphonium chloride （THPC） has been considered as an important chrome-free tanning agent. To understand the THPC tanning mechanism, the structure, charge distribution, activity and tanning abili...Tetra-hydroxymethyl phosphonium chloride （THPC） has been considered as an important chrome-free tanning agent. To understand the THPC tanning mechanism, the structure, charge distribution, activity and tanning ability of each phosphorous compound in THPC tanning system were studied, by ^31p NMR, FT-IR spectroscopy, differential scanning calorimetry （DSC） and computational chemistry method, etc. When pH raised to 6.0, the decomposition of THPC would take place, which results in a production of free formaldehyde, tri-hydroxymethyl phosphonium （TrHP） and tri-hydroxymethyl phosphine oxide （TrHPO）. At pH 9.0, THPC will be converted completely to TrHP and most TrHP is further oxidized into TrHPO. It is possible that, in reaction of phosphorous compounds and collagens, both P-C and C-O bonds would break simultaneously or individually. From molecular charge distribution and bond polar properties, it is deduced that, if P-C bonds break, the activity is in order of TrHPO 〉 THPC 〉 TrHE whereas if C--O bonds break, the order is TrHP 〉 THPC 〉 TrHPO. It is more possible that P--C bonds will break in reaction with collagen, and TrHPO may be more active in the THPC tanning system. The results of tanning and DSC also prove the above conclusion. Furthermore, the fact that the shrinkage temperature of THPC tanned leather was below 70℃ when basified to pH 5.0 or lower suggests that the hydroxymethyl groups of THPC and TrHP are less possible to combine directly with amino groups of collagen.展开更多
Introduction: Omphalocele is an embryopathy of the first ten weeks of gestation. It corresponds to a defect in the abdominal wall through which viscera contained in a sac constituted by the amniotic membrane and cente...Introduction: Omphalocele is an embryopathy of the first ten weeks of gestation. It corresponds to a defect in the abdominal wall through which viscera contained in a sac constituted by the amniotic membrane and centered by the umbilical cord are exteriorized. The objective of this work was to study the diagnostic modalities and the impact of our therapeutic choices on the outcome of the management. Material and Methods: We carried out a prospective study on patients with omphalocele admitted to the pediatric surgery departments of the HND, during a period spread over 4 years, between January 2017 and December 2020. Results: we collected 55 files (i.e., 13.7 cases/year). There were 38 boys and 17 girls (sex ratio 2.2) with an average age of 1.9 days. We found 15 cases (27%) of type I and 40 cases (73%) of type II according to the AITKEN classification. Fifteen cases (27%) benefited from surgical treatment and 45 cases (73%) benefited from conservative treatment (Grob). Two surgical methods were used: Primary parietal closure, which was used in 10 cases (66.7%), and the GROSS method, which was used in 5 cases (33.3%). We obtained an improvement of 40 cases (73%) and 15 cases (27%) of death. Conclusion: our work reported our experience in the management of omphalocele and the difficulties of postoperative resuscitation.展开更多
Silicic acid,commonly derived from cheap and easily available sodium silicate,has recently received great attention for application in leather industry to produce ecological leather with a cleaner approach.However,lea...Silicic acid,commonly derived from cheap and easily available sodium silicate,has recently received great attention for application in leather industry to produce ecological leather with a cleaner approach.However,leather tanned with silicic acid alone is poor in storage stability,which limits its practical application in leather production.In this work,a new environment-friendly combination tannage based on silicic acid and plant tannin was developed to address this issue along with improving the comprehensive performances of leather.The obtained leather was characterized by scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy and so on.The results showed that compared with leather tanned with silicic acid alone,the leather tanned with this combination method possessed improved thermal stability,enhanced mechanical properties,acceptable softness,appropriate hydrophilicity,and especially enhanced storage stability.More importantly,the combination tanned leather with 1:1 of the mass ratio of silicic acid to vegetable tannin(composed of valonea extract and mimosa extract with the same weight)had more prominent comprehensive performances.In addition,the results demonstrated that hydrogen bonding played an important role in the combination tanning process.Furthermore,the hydrogen bonds generated between phenolic hydroxyl groups of polyphenols with silicon hydroxyl groups of silicic acid molecules inhibited the excessive condensation of Si-OH groups between themselves.Subsequently,the assessment of environmental impact revealed the value of BOD 5/COD of the wastewater produced in this combination tanning process is more than 0.3,indicating the chrome-free combination tannage based on silicic acid and plant tannin was an environment-friendly tanning technology.These findings therefore indicated that a new chrome-free tanning method with silicon and biomass materials as main tanning agents has potential practical application prospect in leather production.展开更多
基金the National Basic Research Program (2007CB616909)Startup Foundation of Applied Chemistry of the Key Discipline of Zhejiang University of Technology and Zhejiang Provincial Science and Technology Plan (2006C21107)
文摘Tetra-hydroxymethyl phosphonium chloride （THPC） has been considered as an important chrome-free tanning agent. To understand the THPC tanning mechanism, the structure, charge distribution, activity and tanning ability of each phosphorous compound in THPC tanning system were studied, by ^31p NMR, FT-IR spectroscopy, differential scanning calorimetry （DSC） and computational chemistry method, etc. When pH raised to 6.0, the decomposition of THPC would take place, which results in a production of free formaldehyde, tri-hydroxymethyl phosphonium （TrHP） and tri-hydroxymethyl phosphine oxide （TrHPO）. At pH 9.0, THPC will be converted completely to TrHP and most TrHP is further oxidized into TrHPO. It is possible that, in reaction of phosphorous compounds and collagens, both P-C and C-O bonds would break simultaneously or individually. From molecular charge distribution and bond polar properties, it is deduced that, if P-C bonds break, the activity is in order of TrHPO 〉 THPC 〉 TrHE whereas if C--O bonds break, the order is TrHP 〉 THPC 〉 TrHPO. It is more possible that P--C bonds will break in reaction with collagen, and TrHPO may be more active in the THPC tanning system. The results of tanning and DSC also prove the above conclusion. Furthermore, the fact that the shrinkage temperature of THPC tanned leather was below 70℃ when basified to pH 5.0 or lower suggests that the hydroxymethyl groups of THPC and TrHP are less possible to combine directly with amino groups of collagen.
文摘Introduction: Omphalocele is an embryopathy of the first ten weeks of gestation. It corresponds to a defect in the abdominal wall through which viscera contained in a sac constituted by the amniotic membrane and centered by the umbilical cord are exteriorized. The objective of this work was to study the diagnostic modalities and the impact of our therapeutic choices on the outcome of the management. Material and Methods: We carried out a prospective study on patients with omphalocele admitted to the pediatric surgery departments of the HND, during a period spread over 4 years, between January 2017 and December 2020. Results: we collected 55 files (i.e., 13.7 cases/year). There were 38 boys and 17 girls (sex ratio 2.2) with an average age of 1.9 days. We found 15 cases (27%) of type I and 40 cases (73%) of type II according to the AITKEN classification. Fifteen cases (27%) benefited from surgical treatment and 45 cases (73%) benefited from conservative treatment (Grob). Two surgical methods were used: Primary parietal closure, which was used in 10 cases (66.7%), and the GROSS method, which was used in 5 cases (33.3%). We obtained an improvement of 40 cases (73%) and 15 cases (27%) of death. Conclusion: our work reported our experience in the management of omphalocele and the difficulties of postoperative resuscitation.
基金This research was supported by the National Natural Science Foundation of China(No.21376153)the Fundamental Research Funds for the Central University of China,and Sichuan University-Zschimmer&Schwarz CmbH&Co.KG Scholarships(2020).
文摘Silicic acid,commonly derived from cheap and easily available sodium silicate,has recently received great attention for application in leather industry to produce ecological leather with a cleaner approach.However,leather tanned with silicic acid alone is poor in storage stability,which limits its practical application in leather production.In this work,a new environment-friendly combination tannage based on silicic acid and plant tannin was developed to address this issue along with improving the comprehensive performances of leather.The obtained leather was characterized by scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy and so on.The results showed that compared with leather tanned with silicic acid alone,the leather tanned with this combination method possessed improved thermal stability,enhanced mechanical properties,acceptable softness,appropriate hydrophilicity,and especially enhanced storage stability.More importantly,the combination tanned leather with 1:1 of the mass ratio of silicic acid to vegetable tannin(composed of valonea extract and mimosa extract with the same weight)had more prominent comprehensive performances.In addition,the results demonstrated that hydrogen bonding played an important role in the combination tanning process.Furthermore,the hydrogen bonds generated between phenolic hydroxyl groups of polyphenols with silicon hydroxyl groups of silicic acid molecules inhibited the excessive condensation of Si-OH groups between themselves.Subsequently,the assessment of environmental impact revealed the value of BOD 5/COD of the wastewater produced in this combination tanning process is more than 0.3,indicating the chrome-free combination tannage based on silicic acid and plant tannin was an environment-friendly tanning technology.These findings therefore indicated that a new chrome-free tanning method with silicon and biomass materials as main tanning agents has potential practical application prospect in leather production.
