Ultrafine monolayer Co-containing layered double hydroxide nanosheets for water oxidation

For many two-dimensional(2D)materials,low coordination edges and corner sites offer greatly enhanced catalytic performance compared to basal sites,motivating the search for new synthetic approaches towards ultrathin and ultrafine 2D nanomaterials with high specific surface areas.To date,the synthesis of catalysts that are both ultrathin(monolayer)and ultrafine(lateral size<10nm)has proven extremely challenging.Herein,using a facile ultrasonic exfoliation procedure,we describe the successful synthesis of ultrafine ZnCo-LDH nanosheets(denoted as ZnCo-UF)with a size^3.5 nm and thickness^0.5 nm.The single layer ZnCo-UF nanosheets possess an abundance of oxygen vacancies(Vo)and unsaturated coordination s让es,thereby affording outstanding electrocatalytic water oxidation performance.DFT calculations confirmed that Vo on the surface of ZnCo-UF enhanced H20 adsorption via increasing the electropositivity of the nanosheets.

Neuropeptide Y receptor Y8b(npy8br)regulates feeding and digestion in Japanese medaka(Oryzias latipes)larvae:evidence from gene knockout

Neuropeptide Y receptor Y8(NPY8R)is a fish-specific receptor with two subtypes,NPY8AR and NPY8BR.Changes in expression levels during physiological processes or in vivo regulation after ventricular injection suggest that NPY8BR plays an important role in feeding regulation;this has been found in only a few fish,at present.In order to better understand the physiological function of npy8br,especially in digestion,we used clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)technology to generate npy8br-/-japanese medaka(Oryzias latipes).We found that the deletion of npy8br in medaka larvae affected their feeding and digestion ability,ultimately affecting their growth.Specifically,npy8br deficiency in medaka larvae resulted in decreased feed intake and decreased expression levels of orexigenic genes(npy and agrp).npy8br-/-medaka larvae fed for 10 d(10th day of feeding)still had incompletely digested brine shrimp(Artemia nauplii)in the digestive tract 8 h after feeding,the messenger RNA(mRNA)expression levels of digestion-related genes(amy,lpl,ctra,and ctrb)were significantly decreased,and the activity of amylase,trypsin,and lipase also significantly decreased.The deletion of npy8br in medaka larvae inhibited the growth and significantly decreased the expression of growth-related genes(gh and igf1).Hematoxylin and eosin(H&E)sections of intestinal tissue showed that npy8br-/-medaka larvae had damaged intestine,thinned intestinal wall,and shortened intestinal villi.So far,this is the first npy8br gene knockout model established in fish and the first demonstration that npy8br plays an important role in digestion.

Multifunctional N,S-doped and methionine functionalized carbon dots for on−off−on Fe^(3+)and ascorbic acid sensing,cell imaging,and fluorescent ink applying

Fluorescent carbon dots(CDs)have been identified as potential nanosensors and attracted tremendous research interests in wide areas including anti-counterfeiting,environmental and biological sensing and imaging in considering of the attractive optical properties.In this work,we present a CDs based fluorescent sensor from polyvinylpyrrolidone,citric acid,and methionine as precursors by hydrothermal approach.The selective quantifying of Fe^(3+)and ascorbic acid(AA)are based on the fluorescent on-off-on process,in which the fluorescent quenching is induced by the coordination of the Fe^(3+)on the surface of the CDs,while the fluorescence recovery is mainly attributed to redox reaction between Fe^(3+)and AA,breaking the coordination and bringing the fluorescence back.Inspired by the good water solubility and biocompatibility,significant photostability,superior photobleaching resistance as well as high selectivity,sensitivity,and interference immunity,which are constructed mainly from the N,S-doping and methionine surface functionalization,the CDs have not only been employed as fluorescence ink in multiple anticounterfeiting printing and confidential document writing or transmitting,but also been developed as promising fluorescence sensors in solution and solid by CDs doped test strips and hydrogels for effectively monitoring and removing of Fe^(3+)and AA in environmental aqueous solution.The CDs have been also implemented as effective diagnostic candidates for imaging and tracking of Fe^(3+)and AA in living cells,accelerating the understanding of their function and importance in related biological processes for the prevention and treatment specific diseases.

Hybrid ZnO@Au Nanorod Array for Fast and Repeatable Bacteria Inactivation

Comprehensive Summary,The worldwide abuse of antibiotics and resultant antimicrobial resistance made the development of new antibacterial materials an urgent and significant issue.Herein,a hybrid ZnO@Au nanorod array with fast bacterial inactivation and excellent recyclability was reported.93%bacteria could be inactivated within 5 min ultra-sonication under indoor daylight,and the killing rate maintains above 90%after seven repeated using cycles.Antibacterial mechanism involves extracellular reactive oxygen species(ROS)generated from photocatalysis and piezoelectricity of nanorod array,intracellular ROS generation and decrease of adenosine-triphosphate(ATP)originated from electron transfer(ET)from bacteria to nanorod array,as well as mechanical effect from the nanorod,among which ET mechanism plays a major role.Large Schottky barrier from the hybrid interface not only enhances the ROS generation by promoting the charge transfer and carrier separation as well as light utilization,but also enables one-direction electron transfer from bacteria to nanorod array.The resultant continuous electron loss breaks the energy metabolism and disturbs the redox equilibrium,leading to bacterial death.This study demonstrates the great potential of hybrid structure in antibacterial applications and indicates ET as a novel effective antibacterial mechanism for semiconductor materials,which provides insights into the design of next-generation antibacterial materials.