分割氢键有机框架的孔道空间提升光催化CO_(2)还原效率

氢键有机框架材料(HOFs)在催化领域具有巨大的潜力,但其孔道空间在去除溶剂后易塌陷,限制了其在光催化能源转换和存储方面的应用.本研究采用孔道分割策略成功设计并合成了一种稳定孔道结构、高效光催化CO_(2)还原活性的HOF催化剂.H4TBAPy分子通过与HOF孔道中大量的CH…π相互作用锚定自身,并将HOF的大孔道分隔成多个小空间,显著增加了HOF框架的稳定性.同时,富电子属性的H4TBAPy分子提升了HOF体系中电子的传输速率,从而提高了催化活性.这项研究为设计稳定、高性能的HOFs光催化剂提供了新策略.

Post-modification of metal-organic framework for improved CO_(2) photoreduction efficiency

Utilizing metal-organic frameworks(MOFs) to design photocatalysts for CO_(2) reduction catalysts is an excellent idea but currently restricted by the relatively low activity. Enhancing CO_(2) affinity and tuning the oxidation state of metal clusters in MOFs might be a solution to improve the catalytic performance.Herein, the Cl-bridge atoms in the metal clusters of a cobalt MOF were easily exchanged with OH-,which simultaneously oxidized a portion of Co(Ⅱ) to Co(Ⅲ) and resulted in a much enhanced photocatalytic activity for CO_(2) reduction. In contrast, the original framework does not exhibit such superior activity. Comprehensive characterizations on their physicochemical properties revealed that the introduction of hydroxyl group not only greatly increases the CO_(2) affinity but also alters the oxidation state of metal clusters, resulting in significantly improved photocatalytic activities for CO_(2) reduction. This work provides important insight into the design of efficient photocatalysts.

Tetrahydrobiopterin Protects against Radiation-induced Growth Inhibition in H9c2 Cardiomyocytes

Background：Tetrahydrobiopterin （BH4） is an essential cofactor of nitric oxide synthases （NOSs） for the synthesis of nitric oxide （NO）.BH4 therapy can reverse the disease-related redox disequilibrium observed with BH4 deficiency.However,whether BH4 exerts a protective effect against radiation-induced damage to cardiomyocytes remains unknown.Methods：Clonogenic assays were performed to determine the effects of X-ray on H9c2 cells with or without BH4 treatment.The contents of lactate dehydrogenase （LDH）,superoxide dismutase （SOD）,and malondialdehyde （MDA） in H9c2 cells were measured to investigate oxidative stress levels.The cell cycle undergoing radiation with or without BH4 treatment was detected using flow cytometry.The expression levels of proteins in the phosphatidylinositol 3 kinase （PI3K）/protein kinase B （AKT）/P53 signaling pathway,inducible NOS （iNOS）,and endothelial NOS （eNOS） were examined using Western blotting.Results：X-ray radiation significantly inhibited the growth of H9c2 cells in a dose-dependent manner,whereas BH4 treatment significantly reduced the X-ray radiation-induced growth inhibition （control group vs.X-ray groups,respectively,P 〈 0.0 l）.X-ray radiation induced LDH release,apoptosis,and G0/G 1 peak accumulation,significantly increasing the level of MDA and the production of NO,and decreased the level of SOD （control group vs.X-ray groups,respectively,P 〈 0.05 or P 〈 0.01）.By contrast,BH4 treatment can significantly reverse these processes （BH4 treatment groups vs.X-ray groups,P 〈 0.05 or P 〈 0.01）.BH4 reversed the X-ray radiation-induced expression alterations ofapoptosis-related molecules,including B-cell lymphoma-2 （Bcl-2）,Bcl-2 associated X protein,and caspase-3,and molecules of the PI3K/Akt/P53 signaling pathway.BH4 enhanced the production of NO in 2 Gy and 4 Gy radiated groups by upregulating eNOS protein expression and downregulating iNOS protein expression.Conclusions：BH4 treatment can protect against X-ray-induced cardiomyocyte injury,possibly by recoupling eNOS rather than iNOS.BH4 treatment also decreased oxidative stress in radiated H9c2 cells.

Association of image-defined risk factors,tumor resectability,and prognosis in children with localized neuroblastoma

Background Although localized neuroblastoma has a good prognosis,some cases have undergone treatment failure or recur-rence.Apart from biologic features such as MYCN status,we wondered whether some characteristics of growing tumors are prognostic,such as a well-encapsulated mass without infiltration of vital organs.We analyzed the diagnostic utility of image-defined risk factors(IDRFs)to predict successful treatment and prognosis.The overall goal was to achieve maximum cure rates for patients with localized neuroblastoma through a better understanding of clinical characteristics.Methods We retrospectively reviewed the images of patients with localized neuroblastoma who were enrolled between June 1998 and December 2012 at a single institution in Shanghai,China.Unequivocal categorization regarding IDRFs was available in 67 patients.IDRF was assessed at diagnosis and after four cycles of neoadjuvant chemotherapy,on average.The median follow-up period was 84 months(range: 48-132 months)after diagnosis.Results MRI and CT indicated a total of 177 IDRFs in these 67 patients.Logistic regression analysis revealed a highly significant negative correlation between the numbers of IDRFs and the possibility of complete removal of neuroblastoma.Intraspinal extension of the tumor,compression of the trachea,and encasement of the main artery in localized neuroblastoma were predictors for incomplete tumor resection.According to univariate analysis,≥4 IDRFs and intraspinal extension of the tumor were significant indicators of poor prognosis.Conclusions The number of IDRFs was useful in predicting surgical outcome and event-free survival.The number of IDRFs should be considered in protocol planning,instead of IDRF presence or absence.

Pesticide residue elimination for fruits and vegetables:the mechanisms,applications,and future trends of thermal and non-thermal technologies

Pesticide residues on food are threatening human health and wellbeing,ecological security.Food processing is one of the necessary ways to eliminate residues to guarantee the safety and sustainable development of the environment.This review outlines the mechanisms,applications,and factors influencing the efficiency as well as their limitations of pesticide residue elimination technologies.Conventional thermal processing technologies like drying,blanching,baking,and roasting have been proved to reduce pesticides extensively whereas sometimes concentration effects occur,and more toxic metabolites or by-products are generated.Additionally,the negative effects on quality attributes of fruits and vegetables(F&V)should be considered.Several innovative non-thermal processing technologies like ultrasound,cold plasma,high-pressure processing,and pulsed electric fields have flourished currently,which show great ability to eliminate pesticide residues significantly with minimal impact on the quality of F&V.In particular,heat-sensitive nutrients like ascorbic acid,phenolics,and carotenoids would retain to a great extent.Similarly,these technologies have their limitations.Furthermore,there is much information about combined processing technology affecting the pesticide behaviors of F&V.Finally,the future developments for pesticide elimination of these technologies are identified and discussed.

Synthesis of planar chiral isoquinolinone-fused ferrocenes through palladium-catalyzed C-H functionalization reaction

(S,S)-Me-BI-DIME/Pd(0)-catalyzed ennantioselective C-H functionalization of N-ferrocenyl o-bromobenzanilides has been realized,affording isoquinolinone-fused ferrocenes with up to 97% ee.The products can be transformed into planar chiral ferrocenyl monophosphines,which demonstrate their preliminary application.

Harnessing Electrostatic Interactions for Enhanced Conductivity in Metal-Organic Frameworks

The poor electrical conductivity of metal-organic frameworks(MOFs)has been a stumbling block for its applications in many important fields.Therefore,exploring a simple and effective strategy to regulate the conductivity of MOFs is highly desired.Herein,anionic guest molecules are incorporated inside the pores of a cationic MOF(PFC-8),which increases its conductivity by five orders of magnitude while maintaining the original porosity.In contrast,the same operation in an isoreticular neutral framework(PFC-9)does not bring such a significant change.Theoretical studies reveal that the guest molecules,stabilized inside pores through electrostatic interaction,play the role of electron donors as do in semiconductors,bringing in an analogous n-type semiconductor mechanism for electron conduction.Therefore,we demonstrate that harnessing electrostatic interaction provides a new way to regulate the conductivity of MOFs without necessarily altering the original porous structure.This strategy would greatly broaden MOFs’application potential in electronic and optoelectronic technologies.

Harnessing Electrostatic Interactions for Enhanced Conductivity in Metal-Organic Frameworks

The poor electrical conductivity of metal-organic frameworks(MOFs)has been a stumbling block for its applications in many important fields.Therefore,exploring a simple and effective strategy to regulate the conductivity of MOFs is highly desired.Herein,anionic guest molecules are incorporated inside the pores of a cationic MOF(PFC-8),which increases its conductivity by five orders of magnitude while maintaining the original porosity.In contrast,the same operation in an isoreticular neutral framework(PFC-9)does not bring such a significant change.Theoretical studies reveal that the guest molecules,stabilized inside pores through electrostatic interaction,play the role of electron donors as do in semiconductors,bringing in an analogous n-type semiconductor mechanism for electron conduction.Therefore,we demonstrate that harnessing electrostatic interaction provides a new way to regulate the conductivity of MOFs without necessarily altering the original porous structure.This strategy would greatly broaden MOFs’application potential in electronic and optoelectronic technologies.