Proteoglycans in the central nervous system play integral roles as ＂traffic signals＂ for the direction of neurite outgrowth. This attribute of proteoglycans is a major factor in regeneration of the injured central n...Proteoglycans in the central nervous system play integral roles as ＂traffic signals＂ for the direction of neurite outgrowth. This attribute of proteoglycans is a major factor in regeneration of the injured central nervous system. In this review, the structures of proteoglycans and the evidence suggesting their involvement in the response following spinal cord injury are presented. The review further describes the methods routinely used to determine the effect proteoglycans have on neurite outgrowth. The effects of proteoglycans on neurite outgrowth are not completely understood as there is disagreement on what component of the molecule is interacting with growing neurites and this ambiguity is chronicled in an historical context. Finally, the most recent findings suggesting possible receptors, interactions, and sulfation patterns that may be important in eliciting the effect of proteoglycans on neurite outgrowth are discussed. A greater understanding of the proteoglycan-neurite interaction is necessary for successfully promoting regeneration in the iniured central nervous system.展开更多
The cycloaddition of epoxides and carbon dioxide represents a straightforward and atom-efficient method for synthesis of cyclic carbonates and utilization of CO2. So far, homogeneous metal complexes have been mainly a...The cycloaddition of epoxides and carbon dioxide represents a straightforward and atom-efficient method for synthesis of cyclic carbonates and utilization of CO2. So far, homogeneous metal complexes have been mainly applied for such transformations. Here, we describe the synthesis of novel heterogeneous Zn-based catalysts, which were conveniently prepared by pyrolysis of an active- carbon-supported phenanthroline-ligated Zn(OAc)2 complex. Detail structural characterizations proved the existence of single zinc sites in the active material. Compared to a Zn-based nanoparticle (Zn-NP) catalyst, the resulting single metal atom catalyst (SAC) displayed improved activity and stability for the cycloaddition of epoxides. By applying the optimal catalyst, a variety of carbonates were successfully obtained in high yields with good functional group tolerance.展开更多
The production of bulk organic chemicals has a strong impact on our daily life.In this review,an overview of important industrial processes using homogeneous catalysts is given.Using specific carbonylation and hydroge...The production of bulk organic chemicals has a strong impact on our daily life.In this review,an overview of important industrial processes using homogeneous catalysts is given.Using specific carbonylation and hydrogenation case studies,we want to show how basic research can contribute to the development of such processes and what challenges exist in this area of academic research.展开更多
Acousto-optic devices that use radio frequency mechanical waves to manipulate light are critical components in many optical systems.Here,the researchers bring acousto-optic devices on-chip and make them more efficient...Acousto-optic devices that use radio frequency mechanical waves to manipulate light are critical components in many optical systems.Here,the researchers bring acousto-optic devices on-chip and make them more efficient for integrated photonic circuits.展开更多
The worldwide energy system developed in the past century is highly dependent on non-renewable fossil feedstocks.Hence,the concentration of carbon dioxide(CO_(2))in the atmosphere has continuously increased from 280 p...The worldwide energy system developed in the past century is highly dependent on non-renewable fossil feedstocks.Hence,the concentration of carbon dioxide(CO_(2))in the atmosphere has continuously increased from 280 ppm(parts per million)to>420 ppm since the industrial revolution[1–5].This excessive emission of CO_(2) causes global warming and ocean acidification.In this context,the Paris Agreement on Climate Change adopted in 2015 recognized the necessity of holding the increase of global average temperature below 2℃,preferably 1.5℃,above pre-industrial levels,and reaching a CO_(2)-neutral process by 2050.展开更多
In recent decades,the use of 1,3-butadiene as a comparably cheap and abundant raw material for new applications has attracted more and more interest,specifically in the chemical industry.The present review covers seve...In recent decades,the use of 1,3-butadiene as a comparably cheap and abundant raw material for new applications has attracted more and more interest,specifically in the chemical industry.The present review covers several of the most important homogeneously catalyzed processes and technologies which are currently used or have the potential to produce fine and bulk chemicals from 1,3-butadiene.As an example,palladium-catalyzed telomerizations provide valuable chemicals through the selective dimerization of 1,3-dienes with the simultaneous addition of various nucleophiles,which can be used for the synthesis of 1-octene,1-octanol,and various lactones.On the other hand,direct carbonylation allows the selective introduction of functional groups onto 1,3-dienes,such as carbonyl,carboxyl or ester groups.The key to success in achieving these industrially relevant conversions of 1,3-butadiene was mainly the development of innovative efficient catalysts.We hope this review will make readers familiar with the industrially applied and relevant transformations of 1,3-butadiene and inspire them to further explore new and advanced systems.展开更多
Minimal access surgery (MAS) includes conventional minimally invasive laparoscopic and thoracoscopic surgery, single incision laparoscopic surgery (SILS) and natural orifice transluminal endoscopic surgery (NOTES). An...Minimal access surgery (MAS) includes conventional minimally invasive laparoscopic and thoracoscopic surgery, single incision laparoscopic surgery (SILS) and natural orifice transluminal endoscopic surgery (NOTES). An end of the evolution of MAS is not foreseeable, but there are still limitations. In the most common fields of intestinal surgery (cholecystectomy, appendectomy, colo-rectal resection) limitations of MAS shook dogma for surgical strategy and procedure. Automation units and telesurgical systems try to assist the surgical action. Remaining limitations are caused by lack of tactile sense and spatial awareness. With expanding application of minimal access technique in surgery the need for navigation assistance will increase. Future expansion is basically reliant on the feasibility of navigated surgery. Navigation must respect the problems of organ shift and realise continuous localisation of the surgical target as well as spatial orientation of surgical instruments and camera view.展开更多
基金supported by the NIH(NS53470)the Kentucky Spinal Cord and Head Injury Research Trust(#10-11A)the Department of Defense,CDMRP(SC090248/W81XWH-10-1-0778)
文摘Proteoglycans in the central nervous system play integral roles as ＂traffic signals＂ for the direction of neurite outgrowth. This attribute of proteoglycans is a major factor in regeneration of the injured central nervous system. In this review, the structures of proteoglycans and the evidence suggesting their involvement in the response following spinal cord injury are presented. The review further describes the methods routinely used to determine the effect proteoglycans have on neurite outgrowth. The effects of proteoglycans on neurite outgrowth are not completely understood as there is disagreement on what component of the molecule is interacting with growing neurites and this ambiguity is chronicled in an historical context. Finally, the most recent findings suggesting possible receptors, interactions, and sulfation patterns that may be important in eliciting the effect of proteoglycans on neurite outgrowth are discussed. A greater understanding of the proteoglycan-neurite interaction is necessary for successfully promoting regeneration in the iniured central nervous system.
基金supported by the National Key R&D Program of China(2017YFA0403103)the state of Mecklenburg-Vorpommern and the Bundesministerium für Bildung und Forschung~~
文摘The cycloaddition of epoxides and carbon dioxide represents a straightforward and atom-efficient method for synthesis of cyclic carbonates and utilization of CO2. So far, homogeneous metal complexes have been mainly applied for such transformations. Here, we describe the synthesis of novel heterogeneous Zn-based catalysts, which were conveniently prepared by pyrolysis of an active- carbon-supported phenanthroline-ligated Zn(OAc)2 complex. Detail structural characterizations proved the existence of single zinc sites in the active material. Compared to a Zn-based nanoparticle (Zn-NP) catalyst, the resulting single metal atom catalyst (SAC) displayed improved activity and stability for the cycloaddition of epoxides. By applying the optimal catalyst, a variety of carbonates were successfully obtained in high yields with good functional group tolerance.
基金the support of the European Research Council(ERC NoNaCat grant no.670986)the Federal Ministry of Education and Research(BMBF)the State of Mecklenburg-Vorpommern.
文摘The production of bulk organic chemicals has a strong impact on our daily life.In this review,an overview of important industrial processes using homogeneous catalysts is given.Using specific carbonylation and hydrogenation case studies,we want to show how basic research can contribute to the development of such processes and what challenges exist in this area of academic research.
文摘Acousto-optic devices that use radio frequency mechanical waves to manipulate light are critical components in many optical systems.Here,the researchers bring acousto-optic devices on-chip and make them more efficient for integrated photonic circuits.
基金support from the Alexander von Humboldt Foundation.
文摘The worldwide energy system developed in the past century is highly dependent on non-renewable fossil feedstocks.Hence,the concentration of carbon dioxide(CO_(2))in the atmosphere has continuously increased from 280 ppm(parts per million)to>420 ppm since the industrial revolution[1–5].This excessive emission of CO_(2) causes global warming and ocean acidification.In this context,the Paris Agreement on Climate Change adopted in 2015 recognized the necessity of holding the increase of global average temperature below 2℃,preferably 1.5℃,above pre-industrial levels,and reaching a CO_(2)-neutral process by 2050.
文摘In recent decades,the use of 1,3-butadiene as a comparably cheap and abundant raw material for new applications has attracted more and more interest,specifically in the chemical industry.The present review covers several of the most important homogeneously catalyzed processes and technologies which are currently used or have the potential to produce fine and bulk chemicals from 1,3-butadiene.As an example,palladium-catalyzed telomerizations provide valuable chemicals through the selective dimerization of 1,3-dienes with the simultaneous addition of various nucleophiles,which can be used for the synthesis of 1-octene,1-octanol,and various lactones.On the other hand,direct carbonylation allows the selective introduction of functional groups onto 1,3-dienes,such as carbonyl,carboxyl or ester groups.The key to success in achieving these industrially relevant conversions of 1,3-butadiene was mainly the development of innovative efficient catalysts.We hope this review will make readers familiar with the industrially applied and relevant transformations of 1,3-butadiene and inspire them to further explore new and advanced systems.
文摘Minimal access surgery (MAS) includes conventional minimally invasive laparoscopic and thoracoscopic surgery, single incision laparoscopic surgery (SILS) and natural orifice transluminal endoscopic surgery (NOTES). An end of the evolution of MAS is not foreseeable, but there are still limitations. In the most common fields of intestinal surgery (cholecystectomy, appendectomy, colo-rectal resection) limitations of MAS shook dogma for surgical strategy and procedure. Automation units and telesurgical systems try to assist the surgical action. Remaining limitations are caused by lack of tactile sense and spatial awareness. With expanding application of minimal access technique in surgery the need for navigation assistance will increase. Future expansion is basically reliant on the feasibility of navigated surgery. Navigation must respect the problems of organ shift and realise continuous localisation of the surgical target as well as spatial orientation of surgical instruments and camera view.
