Preventive effect of nasal Timosaponin BII-loaded temperature-/ionsensitive in situ hydrogels on Alzheimer’s disease

Objective:To study the preventive effect of Timosaponin BII(T-BII)-loaded temperature/ion-sensitive nasal in situ hydrogels(ISGs)on Alzheimer's disease(AD),its preparation technology,characteristics and in vivo effects were evaluated.Methods:The morphological and rheological properties were evaluated.The preventive effects of T-BII ISG on scopolamine-induced AD in mice were determined with the index of muscarinicreceptor 1(M1)expression and pathological changes.Results:Results revealed that T-BII ISG significantly increased the content of M1 choline receptors in the hippocampus of mice and ameliorated the damage incurred to the hippocampal cornu ammonis 1(CA1)area.Conclusion:T-BII ISGs is a reasonable and convenient method of exerting an obvious preventive effect on mice with AD induced by scopolamine.This,thereby,lays forth a new treatment option for preventing AD.

Remarkable Wear Resistance in a Complex Concentrated Alloy with Nanohierarchical Architecture and Composition Undulation

Sustained wear damages on the sliding surfaces of alloys are generally the culprit responsible for the failure of various mechanical systems.Inspired by high-entropy effects,here we deliberately deploy nanohierarchical architecture with composition undulation in a Ni50(AlNbTiV)_(50) complex concentrated alloy,which yields ultralow wear rate within the order of 10^(−7) to 10^(−6) mm^(3)/Nm between room temperature and 800℃.Such remarkable wear resistance heretofore represents one of the highest wear resistance reported for the bulk alloys or composites,and originates from the multi-type adaptive friction interface protection governed by intrinsically nano-coupled grains and nanoprecipitates.This cooperative heterostructure releases gradient frictional stress in stages upon wear at room temperature through the coexistence of multiple deformation pathways while activating a dense nanocrystalline glaze layer upon wear at 800℃ to minimize adhesive and oxidative wear.Our work uncovers a practical avenue for tailoring wear properties with multicomponent heterostructures over a wide temperature range.

Insights into varicella-zoster virus assembly from the B-and C-capsid at near-atomic resolution structures

Varicella-zoster is a highly communicable virus that can be transmitted through the airborne route.About one quarter of people are infected with this virus.Previous studies have described the structure of A-capsid and a blurred reconstruction of the C-capsid with icosahedral symmetry.In this study,we have determined the more precise detailed structures of the varicella-zoster virus(VZV)B-and C-capsid in icosahedral symmetry using a combination of block-based reconstruction and symmetry relaxation strategies.In addition,we are reporting structural details of the portal vertex reconstructions in five-fold symmetry and portal reconstructions in twelve-fold symmetry.The structures unveil the basis for the high thermal stability of the VZV capsid.The conformational flexibility of structural elements of the capsid plays a role in the assembly of the capsid and drives processes critical for the viral life cycle.The results of the study open up new avenues for the development of drugs against a highly prevalent and contagious pathogen.

Designing Unpowered Shoulder Complex Exoskeleton via Contralateral Drive for Self-rehabilitation of Post-stroke Hemiparesis

Rehabilitation using exoskeleton robots can effectively remediate dysfunction and restore post-stroke survivors’ physical ability. However, low kinematic compatibility and poor self-participation of post-stroke patients in rehabilitation restrict the outcomes of exoskeleton-based therapy. The study presents an Unpowered Shoulder Complex Exoskeleton (USCE), consisting of Shoulder Girdle Mechanism (SGM), Ball-and-Socket Joint Mechanism (BSM), Gravity Compensating Mechanism (GCM) and Adjustable Alignment Design (AAD), to achieve self-rehabilitation of shoulder via energy transfer from the healthy upper limb to the affected counterpart of post-stroke hemiplegic patients. The SGM and AAD are designed to improve the kinematic compatibility by compensating for displacements of the glenohumeral joint with the adaptable size of USCE for different wearers. The BSM and GCM can transfer the body movement and energy from the healthy half of the body to the affected side without external energy input and enhance the self-participation with sick posture correction. The experimental results show that the USCE can provide high kinematic compatibility with 90.9% movement similarity between human and exoskeleton. Meanwhile, the motion ability of a post-stroke patient’s affected limb can be increased through energy transfer. It is expected that USCE can improve outcomes of home-based self-rehabilitation.

Structures of the portal vertex reveal essential protein-protein interactions for Herpesvirus assembly and maturation

Dear Editor,Herpesviridae is a large family of double-stranded DNA(dsDNA)viruses that cause a variety of human diseases ranging from cold sores and chicken pox to congenital defects,blindness and cancer(Chayavichitsilp et al.,2009;Wang et al.,2018).In the past 70 years,substantial advances in our knowledge of the molecular biology of herpesviruses have led to insights into disease pathogenesis and management.However,the mechanism for capsid assembly that requires the ordered packing of about 4,000 protein subunits into the hexons,pentons and triplexes remains elusive.It is still a puzzle how initially identical subunits adopt both hexameric and pentameric conformations in the capsid and select the correct locations needed to form closed shells of the proper size.Biochemical and genetic studies have shown that the portal is involved in initiation of capsid assembly(Newcomb et al.,2005)and functions akin to a DNA-sensor coupling genome-packaging achieved by a genome-packaging machinery-“terminase complex”(Chen et al.,2020;Yunxiang Yang,2020)with icosahedral capsid maturation(Lokareddy et al.,2017).Structural investigations of the herpesvirus portal have proven challenging due to the small size of this dodecamer,which accounts for less than 1%of the total mass of the capsid protein layer and the technical difficulties involved in resolving non-icosahedral components of such large icosahedral viruses(diameter is∼1,250Å).Efforts of many investigators over two decades have made to reconstruct the cryo-electron microscopy(cryo-EM)structure of herpesvirus portal vertex and more recently near-atomic structures of two herpesvirus(herpes simplex virus type 1(HSV-1)and Kaposi’s sarcoma-associated herpesvirus(KSHV))portal vertices were reported(McElwee et al.,2018;Gong et al.,2019;Liu et al.,2019).

The evaluation/application of Hydrus-2D model for simulating macro-pores flow in loess soil

Soil hydraulic properties were mainly governed by soil structures especially when the structures is full of the connected soil macro-pores.Therefore,the good hydrological models need to be well documented for revealing the process of soil water movement affected by soil medium.The Hydrus-2D model with double domain was recommended in simulating water movement in a heterogeneous medium of soil.To evaluate the performance of the double domain Hydrus-2D model in loess soil,the dynamic of soil wetting front movement in differential loess soil columns under the constant water head were observed and the processes was simulated by Hydrus-2D model under conditions of different soil properties.The results indicated that the Hydrus-2D model was quite good in simulation of loess soil water movements,and the relative errors of simulation results are less than 15%,MRE less than 5%,and R^(2)>0.9.The results provided the appropriate infiltration parameters of loess soil.

Structural changes of a bacteriophage upon DNA packaging and maturation

Dear Editor,Tailed,double-stranded DNA(dsDNA)bacteriophages,which belong to the order of Caudovirales,have a tail attached to a pentameric vertex of the icosahedral capsid shell(head)through a 12-fold portal(Johnson and Chiu,2007).The phages package genomic dsDNA into a round procapsid using the portal in complex with an ATP-dependent terminase complex as the motor.During packaging,the procapsid shell expands to a more angular intermediate to match the size of the viral genome(Guo et al.,2014).When the phage head is full,the portal detects internal pressure and conveys a signal from the inner capsid to the exterior,which triggers a sequence of events-the terminase complex cleaving mature DNA genome from a multi-genome concatemer,the release of the terminase complex from the portal,and the attachment of the tail complex-in the completion of phage assembly(Lander et al.,2006;Johnson and Chiu,2007).At the beginning of phage infection,the tail is responsible for receptor recognition,and the portal and tail act as a tunnel for DNA delivery into the host cytoplasm(Johnson and Chiu,2007).These mechanisms of DNA packaging and ejection may also be conserved in many other DNA viruses,including herpesvirus(Wang et al.,2020;Yang et al.,2020).