Rifapentine, an important antibiotic, was crystallized from methanol solvent in the form of its methanol solvate. The crystal structure of rifapentine methanol solvate belongs to monoclinic, space group P21, with the ...Rifapentine, an important antibiotic, was crystallized from methanol solvent in the form of its methanol solvate. The crystal structure of rifapentine methanol solvate belongs to monoclinic, space group P21, with the unit cell parameters of a = 1.2278（3） nm, b = 1.9768（4） rim, c = 1.2473（3） nm, Z= 2, and β = 112.35（3）. The parallelepiped.morphology was also predicted by Materials Studio simulation program.. The influence of intermolecular in-teraction was taken into account in the attachment energy model. The crystal shape fits the calculated morphology well, which was performed on the potential energy minimized model using a generic DREIDING 2.21 force fieldand developed minimization protocol with derived＇partial charges.展开更多
It is believed that human ancestors evolved the ability to run bipedally approximately 2 million years ago. This form of locomotion may have been important to our survival and likely has influenced the evolution of ou...It is believed that human ancestors evolved the ability to run bipedally approximately 2 million years ago. This form of locomotion may have been important to our survival and likely has influenced the evolution of our body form. As our bodies have adapted to run, it seems unusual that up to 79% of modern day runners are injured annually. The etiology of these injuries is clearly multifactorial. However, 1 aspect of running that has significantly changed over the past 50 years is the footwear we use. Modern running shoes have become increasingly cushioned and supportive, and have changed the way we run. In particular, they have altered our footstrike pattern from a predominantly forefoot strike(FFS) landing to a predominantly rearfoot strike(RFS) landing. This change alters the way in which the body is loaded and may be contributing to the high rate of injuries runners experience while engaged in an activity for which they were adapted. In this paper, we will examine the benefits of barefoot running(typically an FFS pattern),and compare the lower extremity mechanics between FFS and RFS. The implications of these mechanical differences, in terms of injury, will be discussed. We will then provide evidence to support our contention that FFS provides an optimal mechanical environment for specific foot and ankle structures, such as the heel pad, the plantar fascia, and the Achilles tendon. The importance of footwear will then be addressed, highlighting its interaction with strike pattern on mechanics. This analysis will underscore why footwear matters when assessing mechanics. Finally, proper preparation and safe transition to an FFS pattern in minimal shoes will be emphasized. Through the discussion of the current literature, we will develop a justification for returning to running in the way for which we were adapted to reduce running-related injuries.展开更多
Bimetallic PtxCuy nanocrystals （NCs） with well-defined hexa-pod morphology were synthesized via a wet chemistry approach. The as-synthesized convex NCs with dimensions of around 20 nm show exposed low-index （111） ...Bimetallic PtxCuy nanocrystals （NCs） with well-defined hexa-pod morphology were synthesized via a wet chemistry approach. The as-synthesized convex NCs with dimensions of around 20 nm show exposed low-index （111） facets on the seeds and various high-index facets on the pods. The growth mechanism involved preferred growth along the 〈100〉 crystallographic direction on cuboctahedral seeds. The synthetic protocol could be applied to the synthesis of PtxCuy NCs with various Cu/Pt ratios. The electro-catalytic activity of the hexa-pod PtxCuy NCs supported on carbon black towards the oxygen reduction reaction （ORR） was studied. The hexa-pod PtCu2/C catalysts exhibit the highest specific activity （3.7 mA/cm^2pt） and mass activity （2.4 A/mget） reported to date for PtxCuy. Comparison with other morphological forms of PtxCuy indicated that the enhanced activity originated from morphological factors. The existence of high-index facets as well as abundant edges and steps on the pods could reasonably explain the enhanced catalytic activity. The hexa-pod PtxCuy/C catalysts also show high morphological stability and activity after accelerated durability tests. The as-synthesized hexa-pod PtxCuy NCs have high potential as cathode electro-catalysts for proton exchange membrane fuel cells.展开更多
基金Supported by Open Fund of Mineral Resources Chemistry Key Laboratory of Scihuan Higher Education Institutions
文摘Rifapentine, an important antibiotic, was crystallized from methanol solvent in the form of its methanol solvate. The crystal structure of rifapentine methanol solvate belongs to monoclinic, space group P21, with the unit cell parameters of a = 1.2278（3） nm, b = 1.9768（4） rim, c = 1.2473（3） nm, Z= 2, and β = 112.35（3）. The parallelepiped.morphology was also predicted by Materials Studio simulation program.. The influence of intermolecular in-teraction was taken into account in the attachment energy model. The crystal shape fits the calculated morphology well, which was performed on the potential energy minimized model using a generic DREIDING 2.21 force fieldand developed minimization protocol with derived＇partial charges.
文摘It is believed that human ancestors evolved the ability to run bipedally approximately 2 million years ago. This form of locomotion may have been important to our survival and likely has influenced the evolution of our body form. As our bodies have adapted to run, it seems unusual that up to 79% of modern day runners are injured annually. The etiology of these injuries is clearly multifactorial. However, 1 aspect of running that has significantly changed over the past 50 years is the footwear we use. Modern running shoes have become increasingly cushioned and supportive, and have changed the way we run. In particular, they have altered our footstrike pattern from a predominantly forefoot strike(FFS) landing to a predominantly rearfoot strike(RFS) landing. This change alters the way in which the body is loaded and may be contributing to the high rate of injuries runners experience while engaged in an activity for which they were adapted. In this paper, we will examine the benefits of barefoot running(typically an FFS pattern),and compare the lower extremity mechanics between FFS and RFS. The implications of these mechanical differences, in terms of injury, will be discussed. We will then provide evidence to support our contention that FFS provides an optimal mechanical environment for specific foot and ankle structures, such as the heel pad, the plantar fascia, and the Achilles tendon. The importance of footwear will then be addressed, highlighting its interaction with strike pattern on mechanics. This analysis will underscore why footwear matters when assessing mechanics. Finally, proper preparation and safe transition to an FFS pattern in minimal shoes will be emphasized. Through the discussion of the current literature, we will develop a justification for returning to running in the way for which we were adapted to reduce running-related injuries.
基金We acknowledge the Microstructure Laboratory for Energy Materials （MLEM） at CUP for the technical support with TEM. We also acknowledge the funding support from the National Natural Science Foundation of China （No. 21303265）, Ph.D. Programs Foundation of Ministry of Education of China （No. 20130007120012） and Young Talent Award of CUP （No. YJRC-2013-46）.
文摘Bimetallic PtxCuy nanocrystals （NCs） with well-defined hexa-pod morphology were synthesized via a wet chemistry approach. The as-synthesized convex NCs with dimensions of around 20 nm show exposed low-index （111） facets on the seeds and various high-index facets on the pods. The growth mechanism involved preferred growth along the 〈100〉 crystallographic direction on cuboctahedral seeds. The synthetic protocol could be applied to the synthesis of PtxCuy NCs with various Cu/Pt ratios. The electro-catalytic activity of the hexa-pod PtxCuy NCs supported on carbon black towards the oxygen reduction reaction （ORR） was studied. The hexa-pod PtCu2/C catalysts exhibit the highest specific activity （3.7 mA/cm^2pt） and mass activity （2.4 A/mget） reported to date for PtxCuy. Comparison with other morphological forms of PtxCuy indicated that the enhanced activity originated from morphological factors. The existence of high-index facets as well as abundant edges and steps on the pods could reasonably explain the enhanced catalytic activity. The hexa-pod PtxCuy/C catalysts also show high morphological stability and activity after accelerated durability tests. The as-synthesized hexa-pod PtxCuy NCs have high potential as cathode electro-catalysts for proton exchange membrane fuel cells.
