ICAM-1 depletion in the center of immunological synapses is important for calcium releasing in T-cells

T-cell activation requires the formation of the immunological sy napse(IS)bet ween a T-cll and anantigen-presenting cell(AP C)to control the development of the adaptive immune response.How-ever,calcium release,an initial signal of T-cell activation,has been found to occur before IS for-mation.The mechanism for triggering the calcium signaling and relationship bet ween calciumrelease and IS format ion remains unclear.Herein,using live-cell imaging,we found that int ercellularadhesion molecule 1(ICAM-1),an essential mdlecule for IS formation,accumulated and then wasdepleted at the center of the synapse before complete IS formation.During the proces of ICAM1depletion,calcium was released.if ICAM-1 failed to be depleted from the center of the synapse,thesustained calcium signaling could not be induced.Moreover,depletion of ICAM-1 in ISs preferen-tially ccurred with the contact of antigen-specific T-cels and dendritic clls(DCs).Blocking thebinding ofICA M-1 and lymphocy te finction-associated antigen 1(LFA-1),ICAM-1 failed to depleteat the center of the synapse,and calcium release in T-clls decreased.In studying the mechanism ofhow the depletion ofiCA M1 could influence calcium release in T-clls,we found that the movementof ICAM-1 was associat ed with the localization of LFA-1 in the IS,which afected the localization ofcalcium microdomains,ORAIl and mitochondria in IS.Therefore,the depletion of ICAM-1 in the center of the synapse is an important factor for an initial sust ained calcium release in T-cells.

Tailoring morphology symmetry of bismuth vanadate photocatalysts for efficient charge separation

Although spatial charge separation between different facets of semiconductor crystals has been recognized as a general strategy in photocatalysis, the vital role of crystal morphology symmetry in charge separation properties still remains elusive. Herein,taking monoclinic bismuth vanadate(BiVO_(4)) as a platform, we found distinct charge separation difference via rationally tailoring the morphology symmetry from octahedral to truncated octahedral crystals. For octahedral BiVO_(4), photogenerated electrons and holes can be separated between edges and quasi-equivalent facets. However, as for truncated octahedral crystals,photogenerated electrons tend to transfer to {010} facets while photogenerated holes prefer to accumulate on {120} facets, thus realizing the spatial separation of photogenerated charge between different facets. Morphology tailoring of BiVO_(4) crystals leads to a significantly improved photogenerated charge separation efficiency and photocatalytic water oxidation activity. The built-in electric field for driving the separation of photogenerated electrons and holes is considered to be modulated by tuning the morphology symmetry of BiVO_(4) crystals. This work discloses the significant roles of morphology symmetry in photogenerated charge separation and facilitates the rational design of artificial photocatalysts.

Nanostructures and catalytic atoms engineering of tellurium-based materials and their roles in electrochemical energy conversion

With the dramatic developments of renewable and environmental-friendly electrochemical energy conversion systems,there is an urgent need to fabricate durable and efficient electrocatalysts to address the limitation of high overpotentials exceeding thermodynamic requirements to facilitate practical applications.Recently,tellurium-based nanomaterials(Te NMs)with unique chemical,electronic,and topological properties,including Te-derived nanostructures and transition metal tellurides(TMTs),have emerged as one of the most promising electrocatalytic materials.In the absence of comprehensive and guiding reviews,this review comprehensively summarizes the main advances in designing emerging Te NMs for electrocatalysis.First,the engineering strategies and principles of Te NMs to enhance their electrocatalytic activity and stability from the nanostructures to the catalytic atoms are discussed in detail,especially on the chemical/physical/multiplex templating strategies,heteroatom doping,vacancy/defect engineering,phase engineering,and the corresponding mechanisms and structure-performance correlations.Then,typical applications of Te NMs in electrocatalysis are also discussed in detail.Finally,the existing key issues and main challenges of Te NMs for electrocatalysis are highlighted,and the development trend of Te NMs as electrocatalysts is expounded.This review provides new concepts to guide future directions for developing Te NMs-based electrocatalysts,thereby promoting their future wide applications in electrochemical energy systems.

Design method for freeform reflective-imaging systems with low surface-figure-error sensitivity

Freeform surfaces are difficult to manufacture due to their lack of rotational symmetry. To reduce the requirements for manufacturing precision, a design method is proposed for freeform reflective-imaging systems with low surfacefigure-error sensitivity. The method considers both the surface-figure-error sensitivity and optical specifications,which can design initial systems insensitive to surface figure errors. Design starts with an initial planar system;the surface-figure-error sensitivity of the system is reduced during construction. The proposed method and another that is irrelevant to figure-error sensitivity are used to design a freeform off-axis three-mirror imaging system.Comparison of the sensitivities of the two systems indicates the superiority of our proposed method.