VabHLH137 promotes proanthocyanidin and anthocyanin biosynthesis and enhances resistance to Colletotrichum gloeosporioides in grapevine

Proanthocyanidins(PAs)and anthocyanins are involved in the response of plants to various environmental stresses.However,the mechanism behind defense-induced PA biosynthetic regulation is still not completely elucidated,also in grapevine.This study performed a transcriptome sequencing analysis of grape berries infected with Colletotrichum gloeosporioides to highlight the induction of the VabHLH137 factor from the basic helix-loop-helix(bHLH)XII subfamily by the fungus,which appeared to be significantly co-expressedwith PA-related genes.The functional analysis of VabHLH137 overexpression and knockdownin transgenic grape calli showed that it positively regulated PA and anthocyanin biosynthesis.Moreover,VabHLH137 overexpression in the grape calli significantly increased resistance to C.gloeosporioides.A yeast one-hybrid and electrophoretic mobility shift assay revealed that VabHLH137 directly bound to the VaLAR2 promoter,enhancing its activity and interacting with VaMYBPAR,a transcriptional activator of PA biosynthesis.Furthermore,transient experiments showed that although the VabHLH137+VaMYBPAR complex activated VaLAR2 expression,it failed to further enhance VaLAR2 expression compared to VaMYBPAR alone.The findings indicated that VabHLH137 enhanced PA biosynthesis by activating of VaLAR2 expression,providing new insight into the transcriptional regulation of defense-induced PA biosynthesis in grapevine.

View Types and Visual Communication Cues for Remote Collaboration

Over the last several years,remote collaboration has been getting more attention in the research community because of the COVID-19 pandemic.In previous studies,researchers have investigated the effect of adding visual communication cues or shared views in collaboration,but there has not been any previous study exploring the influence between them.In this paper,we investigate the influence of view types on the use of visual communication cues.We compared the use of the three visual cues(hand gesture,a pointer with hand gesture,and sketches with hand gesture)across two view types(dependent and independent views),respectively.We conducted a user study,and the results showed that hand gesture and sketches with the hand gesture cueswerewell matchedwith the dependent viewcondition,and using a pointer with the hand gesture cue was suited to the independent view condition.With the dependent view,the hand gesture and sketch cues required less mental effort for collaborative communication,had better usability,provided better message understanding,and increased feeling of co-presence compared to the independent view.Since the dependent view supported the same viewpoint between the remote expert and a local worker,the local worker could easily understand the remote expert’s hand gestures.In contrast,in the independent view case,when they had different viewpoints,it was not easy for the local worker to understand the remote expert’s hand gestures.The sketch cue had a benefit of showing the final position and orientation of the manipulating objects with the dependent view,but this benefit was less obvious in the independent view case(which provided a further view compared to the dependent view)because precise drawing in the sketches was difficult from a distance.On the contrary,a pointer with the hand gesture cue required less mental effort to collaborate,had better usability,provided better message understanding,and an increased feeling of co-presence in the independent view condition than in the dependent view condition.The pointer cue could be used instead of a hand gesture in the independent view condition because the pointer could still show precise pointing information regardless of the view type.

Color myth:anthocyanins reactions and enological approaches achieving their stabilization in the aging process of red wine

Color is a crucial sensory indicator of wine quality.However,changes in anthocyanin concentration and profile occur during wine aging,resulting in noticeable reductions in chroma and shifts in hue from purple to brick red.This is because monomeric anthocyanins degrade and derivative anthocyanins form.The rate of color changes can vary depending on complex factors,such as the anthocyanin content of the must,oenological technology,and environmental conditions,which makes the management of red wine color evolution challenging.To address this issue,appropriate winemaking techniques are required to achieve an elegant wine color.This review summarizes the mechanisms related to anthocyanin stability,including glycosylation,acetylation,and derivatization.The review also discusses factors influencing red wine color fading for specific grape varieties and wine appellations,offering time-and cost-efficient techniques to accelerate anthocyanin derivatization and color stabilization.

Down-regulation of Homer1b/c expression protects cultured neurons after traumatic injury

Activation of metabotropic glutamate receptor la aggravates traumatic brain injury. The constitutively expressed protein Homerlb/c participates in delivering and anchoring metabotropic glutamate receptors in neurons. Here, we aimed to verify whether down-regulation of Homerlb/c by RNA interference could protect cultured rat cortical neurons from traumatic injury. We showed that 36 hours after transfection of Homerlb/c small interfering RNA, metabotropic glutamate receptor la was present only in the neuronal cytoplasm, but not in the dendrites. Calcium fluorescence intensity was also decreased significantly. Moreover, lactate dehydrogenase concentration was significantly decreased in Homerlb/c small interfering RNA-transfected cells compared with that in untransfected and control small interfering RNA-transfected cells 24 hours after traumatic neuronal injury. Our findings indicate that down-regulation of Homerlb/c could reduce metabotropic glutamate receptor la transfer from the cell body to the dendrite, relieve calcium overload, and protect neurons from traumatic injury.

Prototyping and Evaluating a Wearable System for Mobile Distributed Collaboration

We have developed a wearable system for mobile distributed collaboration called HandsInAir using emerging wireless and mobile technologies. This system was developed to support real world scenarios in which a remote mobile helper guides a local mobile worker in the completion of a physical task. HandsInAir consists of a helper unit and a worker unit. Both units are equipped with wearable devices having the same hardware configuration, but running different pieces of software to support the distinct roles of the collaborators (helper and worker). The two sides are connected via a wireless network and the collaboration partners can communicate with each other via audio and visual links. In this paper we describe the technical implementation of the system and present a preliminary evaluation of it. The paper concludes with a brief discussion of possible future work for further improvements and new developments.

审计驱动智慧校园治理模式探索

在推进国家治理体系和治理能力现代化的大背景下,探索高校智慧校园现代治理体系是其中一项重要课题。本文以A高校政府审计中的“一卡通”板块为案例,探讨关注的重点内容、发现的主要问题及其背后原因,并以此为基点引出对“以数据资产为核心的价值共创”智慧校园治理新模式的探索与研究,包括治理机制革新、组织结构创新、技术架构赋能、保障机制完善四个方面,从而带动整个治理生态的升级。

Analysis of the False Alarm Fault in Antenna-servo System of Weather Radar

A false alarm fault frequently appeared in antenna-servo system of the CINRAD/SA weather radar of Shanwei in the second half of 2011, so possible reasons for the false alarm fault were listed firstly using method of exhaustion, and then the main reason was determined using exclusive method. That is, the fault was closely related to the signal transmission channel from the antenna mount to servo system in RDA cabinet. After ex- amining questionable nodes in the transmission channels of the alarm signal, we found that the false alarm fault might result from the interference of a burr in the temperature sensing circuit of the elevation motor. In actual operation, a filter capacitor was connected with the corresponding pin in the upper optical board to screen the interference of a burr, thereby successfully eliminating the false alarm fault in antenna-servo system of the CIN- RAD/SA radar of Shanwei.

Solidification microstructure evolution and its correlations with mechanical properties and damping capacities of Mg-Al-based alloy fabricated using wire and arc additive manufacturing

Magnesium(Mg)alloys,as the lightest metal structural material with good damping capacities,have im-portant application prospects in realizing structural lightweight and vibration reduction.However,their engineering application is greatly limited by poor plastic formability.Wire and arc additive manufactur-ing(WAAM)provides a potential approach for fabricating large-scale Mg alloy components with high manufacturing flexibility.In this study,the evolution of the solidification microstructure of a WAAM-processed Mg-Al-based alloy was quantitatively analyzed based on the analytical models;then,the cor-relations between the solidification microstructure and mechanical properties/damping capacities were investigated.The results revealed that the WAAM-processed Mg-Al-based alloy with an equiaxed-grain-dominated microstructure displayed a simultaneous enhancement in mechanical properties and damping capacities compared to those of the cast Mg-Al-based alloy.The good combination of mechanical prop-erties and damping capacities are mainly attributed to the weakened basal texture with a relatively high Schmid factor for basalslip,the twinning-induced plasticity(TWIP)effect associated with the profuse{10-12}tensile twinning,and the relatively high dislocation density caused by the thermal stress during the WAAM process.

Laser powder bed fusion of Zr-modified Al-Cu-Mg alloy:Processability and elevated-temperature mechanical properties

Zr modification is an effective method for improving hot-cracking resistance and elevated-temperature mechanical properties during laser powder bed fusion(L-PBF)of traditional medium and high strength wrought aluminum alloys.This study investigated the l-PBF processability and elevated-temperature mechanical properties of a Zr-modified 2024Al alloy.It was found that the hot-cracking susceptibility increased with the increased scanning speed,which was in reasonable agreement with the modified Rappaz-Drezet-Gremaud criterion.Furthermore,the primary L1_(2)-Al_(3)Zr precipitates,which acted as ef-ficient nucleation sites,precipitated at the fusion boundary of the melt pool,leading to the formation of a heterogeneous grain structure.The yield strength(YS)of the as-fabricated samples at 150,250,and 350℃was 363,210,and 48 MPa,respectively.Despite the slight decrease to 360 MPa of the YS when tested at 150℃,owing to the additional precipitate strengthening from the L1_(2)-Al_(3)Zr precipitates,the YS achieved yield strengths of 253 and 69 MPa,an increase of 20.5%and 30.4%,when tested at 250 and 350℃,respectively.The yield strengths in both the as-fabricated and T6-treated conditions tested at 150 and 250℃were comparable to those of casting Al-Cu-Mg-Ag alloys and superior to those of traditionally heat-resistant 2219-T6 and 2618-T6 of Al-Cu alloys.

Globularization Mechanism and Near Isotropic Properties in Subcritical Heat‑Treated Ti6Al4V Fabricated by Directed Energy Deposition

Microstructure with globularαphase is desirable as it contributes to preferable comprehensive mechanical properties for titanium alloys.However,titanium alloys fabricated by directed energy deposition(DED)are mainly characterized by the lamellarαphase within the basket-weave microstructure,which often leads to severe anisotropy and inferior low cycle fatigue(LCF)properties.To address this,the subcritical annealing and the cyclic annealing were applied to DED Ti–6Al–4V in order to achieve the transformation from the lamellarαphase to the globularαphase.The microstructural characteristics and the globularization behavior ofαphase during heat treatment were investigated.The results show that the aspect ratio ofαis significantly decreased with the subcritical annealing due to the coarsening of lamellarα.Furthermore,the globularαis obtained with the cyclic annealing as a combination result of the termination dissolution and the side surface growth of the lamellarα.These contribute to a pronounced reduction of 85.4%in the ductility anisotropy,compared with the as-built specimens,and superior comprehensive mechanical properties including LCF are achieved with the formation of globularα.

Direct observation of the Mpemba effect with water:Probe the mysterious heat transfer

The Mpemba effect is one of the most perplexing puzzles in nature.Although it has been discussed extensively,direct observation of the Mpemba effect is extremely challenging and rare.Herein,we report the first systematic study of the Mpemba effect with water and clearly point out the conditions required for the observation of the Mpemba effect.The results demonstrate that hot water usually has a faster cooling rate than cold water.The initial temperature,temperature difference,shape of the container,and water volume influence the heat exchange and the cooling process.Owing to the influential factors of heat exchange,the Mpemba effect can only be observed under specific conditions.This work helps to clarify doubts and confusion about the Mpemba effect and can offer alternative strategies for energy storage and transfer materials.

Influence of travel speed on microstructure and mechanical properties of wire + arc additively manufactured 2219 aluminum alloy

Wire+arc additive manufacturing(WAAM)was preliminarily employed to fabricate the 2219 aluminum alloy.The influence of the electric arc travel speed(TS)on the macro-morphology,microstructure,and mechanical properties were investigated.The results indicated that as the electric arc TS increased,the size and the volume fraction of equiaxed grain decreased.The high arc TS during WAAM also promoted the precipitation of theθ(Al2Cu)phase.The volume fractions ofθ’’andθ’phases reached maximum values when TS is 350 and 250 mm/min,respectively.The thermal cycle facilitated the precipitation of theθ’phase.In addition,the micro-hardness and tensile strength of the alloy were analyzed,and the results indicated that samples fabricated at TS of 350 mm/min possessed finer equiaxed grain and exhibited higher ultimate tensile strength(273.5 MPa)and yield strength(182.9 MPa)compared to those fabricated at 250 mm/min.

High strength and ductility of 34CrNiMo6 steel produced by laser solid forming

Because of the excellent mechanical properties of 34 CrNiMo6 steel, it is widely used in high-value components. Many conventional approaches to strengthening-steels typically involve the loss of useful ductility.In this study, 34 CrNiMo6 Steel having high strength and ductility is produced by laser solid forming(LSF)with a quenching-tempering(QT) treatment. Tempering of bainite is mainly by solid phase transformation in the previous LSF layers during the LSF process. The stable microstructure of LSF consists of ferrite and fine carbides. The microstructure transfers to tempered sorbite after heat-treatment. The tensile properties of the LSF steel meet those of the wrought standard. The UTS and elongation of LSF sample at 858 MPa, 19.2%, respectively, are greater than those of the wrought. The QT treatment enhanced the ultimate tensile strength and yield strength of the LSF sample. The ultimate tensile strength, yield strength, reduction in area, and elongation of the LSF+QT sample at 980 MPa, 916 MPa, 58.9%, and 13.9%,respectively, are greater than those of the wrought standard. The yield strength of the LSF+QT sample is approximately 1.27 times that of the wrought. The LSF samples failed in a ductile fracture mode, while the LSF+QT samples showed mixed-mode failure. The defects have only a small effect on the tensile properties owing to the excellent ductility of the LSF sample.

Microstructure and properties of Ti-6Al-4V fabricated by low-power pulsed laser directed energy deposition

Thin-wall structures of Ti-6A1-4V were fabricated by low-power pulsed laser directed energy deposition. During deposition, consistent with prior reports, columnar grains were observed which grew from the bottom toward the top of melt pool tail. This resulted in a microstructure mainly composed of long and thin prior epitaxial β columnar grains (average width ^200μm). A periodic pattern in epitaxial growth of grains was observed, which was shown to depend upon laser traverse direction. Utilizing this, a novel means was proposed to determine accurately the fusion boundary of each deposited layer by inspection of the periodic wave patterns. As a result it was applied to investigate the influence of thermal cycling on microstructure evolution. Results showed that acicular martensite,α' phase, and a small amount of Widmanstatten, a laths, gradually converted to elongated acicular a and a large fraction of Widmanstatten a laths under layer-wise thermal cycling. Tensile tests showed that the yield strength, ultimate tensile strength and elongation of Ti-6Al-4V thin wall in the build direction were 9.1 %, 17.3% and 42% higher respectively than those typically observed in forged solids of the same alloy. It also showed the yield strength and ultimate tensile strength of the transverse tensile samples both were 13.3% higher than those from the build direction due to the strengthening effect of a large number of vertical β grain boundaries, but the elongation was 69.7% lower than that of the build direction due to the uneven grain deformation of β grains.

Influence of post-heat treatment on the microstructure and mechanical properties of Al-Cu-Mg-Zr alloy manufactured by selective laser melting

The properties of modified conventional wrought aluminum alloys cannot be significantly enhanced by normal post-heat treatment in that the fine-grained strengthening,arising from high cooling rate in SLM,is underutilized.In this work,compared with the normal T6 heat treatment,a novel simple direct aging regime was proposed to maintain the grain-boundary strengthening and to utilize the precipitation strengthening of secondary AlZr.It was found that a heterogeneous grain structure,which consisted of ultrafine equiaxed(~0.82μm)and columnar(~1.80μm)grains at the bottom and top of molten pool,respectively,was formed in the SLM processed sample.After direct aging(DA),the ultrafine grains were maintained and a mass of spherical coherent L1-AlZr particles with a mean radius of approximately1.15 nm was precipitated.In contrast,after solution treatment and aging(STA),a significant grain coarsening occurred in the equiaxed grain region.Meanwhile,the coarsening L1-AlZr particles,nano-sized S phases and GPB zones were detected in the STA sample.This subsequently induced that the yield strength of the DA sample(~435 MPa)was higher than that of the STA sample(~402 MPa)owing to the grain boundary strengthening and precipitation strengthening.Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6 alloy(~393 MPa).Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6alloy(~393 MPa).

Laser-based directed energy deposition of novel Sc/Zr-modified Al-Mg alloys:columnar-to-equiaxed transition and aging hardening behavior

The control of grain morphology is important in laser additive manufacturing(LAM),as grain morphology further affects the hot cracking resistance,anisotropy,and strength–ductility synergy of materials.To develop a solidification-control solution and achieve columnar-to-equiaxed transition(CET)in Al-based alloys during LAM,Sc-and-Zr-modified Al-Mg alloys were processed via directed energy deposition(DED).CET was achieved by introducing high potent primary Al_(3)(Sc,Zr)nucleation sites ahead of the solidification interface.Furthermore,the relationship between the solidification control parameters and precipitation behavior of primary Al_(3)(Sc,Zr)nucleation sites was established using the time-dependent nucleation theory.Then,the CET was studied according to the Hunt criterion.The results indicated that coarse columnar grain structure was still obtained at the inner region of the molten pool at low Sc/Zr contents owing to the effective suppression of the precipitation of the primary Al_(3)(Sc,Zr)nucleation sites via rapid solidification during DED.In addition,the relatively low melt temperature at the fusion boundary unavoidably promoted the precipitation of primary Al_(3)(Sc,Zr)nucleation sites,which resulted in a fine equiaxed grains band at the edge of the molten pool.As the Sc/Zr content increased,the solidification cooling rate was not sufficient to suppress the precipitation of the primary Al_(3)(Sc,Zr)nucleation sites,and a fully equiaxed grain structure was obtained.Furthermore,the effect of the layer-by-layer manufacturing process on the subsequent precipitation strengthening of secondary Al_(3)(Sc,Zr)precipitates was discussed.Both the remelting and subsequent aging during thermal cycling should be considered to achieve greater precipitation strengthening.

Overcoming the limitation of in-situ microstructural control in laser additive manufactured Ti-6Al-4V alloy to enhanced mechanical performance by integration of synchronous induction heating

Although a variety of processing routes were developed to in-situ manipulate microstructure for fabricating high-performance Ti-6Al-4 V alloy by directed energy deposition(DED),the in-situ microstructural control ability has been limited and lead to a narrowed mechanical property control range.This work proved the microstructural correlation betweenβ-grains andα-laths resulting from the unique thermal characteristics of DED for the first time and solved such a dilemma through synchronous induction heating assisted laser deposition(SILD)technology.The results confirmed that the laser energy and inductive energy have a different effect on the solidification and solid phase transformation conditions.By adjusting the laser-induction parameters,the microstructural correlation can be tuned;theβ-grains andα-laths can be controlled relatively separately,thereby significantly enhancing the ductility of as-deposited sample(elongation from 14.2%to 20.1%).Furthermore,the mechanical properties of the tuned microstructures are even comparable to that of DED Ti-6Al-4 V with post heat treatment,which indicates that the potential of SILD to be a one-step manufacturing process to fabricate high performance components without post heat treatment.Furthermore,the tensile testing results of the tuned microstructures indicate thatα-lath size is more influential on the mechanical properties than theβ-grain size due to its stronger hindering effect on the slipping of dislocations.This work promotes the understanding of the microstructural formation mechanism in DED titanium alloy and proves that the combination of synchronous induction and laser can expand the ability to control the microstructure and properties of multi-layer deposition.

Zebrafish hhex-null mutant develops an intrahepatic intestinal tube due to de-repression of cdx1b and pdx1

The hepatopancreatic duct (HPD) system links the liver and pancreas to the intestinal tube and is composed of the extrahepatic biliary duct, gallbladder, and pancreatic duct. Haematopoietically expressed-homeobox (Hhex) protein plays an essential role in the establishment of HPD;however, the molecular mechanism remains elusive. Here, we show that zebrafish hhex-null mutants fail to develop the HPD system characterized by lacking the biliary marker Annexin A4 and the HPD marker sox9b. The hepatobiliary duct part of the mutant HPD system is replaced by an intrahepatic intestinal tube characterized by expressing the intestinal marker fatty acid-binding protein 2a (fabp2a). Cell lineage analysis showed that this intrahepatic intestinal tube is not originated from hepatocytes or cholangiocytes. Further analysis revealed that cdx1b and pdx1 are expressed ectopically in the intrahepatic intestinal tube and knockdown of cdx1b and pdx1 could restore the expression of sox9b in the mutant. Chromatin-immunoprecipitation analysis showed that Hhex binds to the promoters of pdx1 and cdx1b genes to repress their expression. We therefore propose that Hhex, Cdx1b, Pdx1, and Sox9b form a genetic network governing the patterning and morphogenesis of the HPD and digestive tract systems in zebrafish.

Laser powder bed fusion of high-strength Sc/Zr-modified Al–Mg alloy:phase selection,microstructural/mechanical heterogeneity,and tensile deformation behavior

Laser powder bed fusion(L-PBF)of Sc/Zr-modified Al-based alloys has recently become a promising method for developing a new generation of high-performance Al alloys.To clarify the modification roles of Sc/Zr elements,an Al–4.66Mg–0.48Mn–0.72Sc–0.33Zr(wt.%)alloy was processed using L-PBF.The effect of the local solidification condition of the molten pool on the precipitation behavior of primary Al_(3)(Sc,Zr)was analyzed based on time-dependent nucleation theory.It was found that primary Al_(3)(Sc,Zr)inevitably precipitated at the fusion boundary,while its precipitation could be effectively suppressed in the inner region of the molten pool.This subsequently induced the formation of a heterogeneousα-Al matrix.After direct aging,the heredity of solidification microstructure introduced heterogeneous secondary Al_(3)(Sc,Zr)precipitates withinα-Al matrix.Owing to the inverse relationship between grain boundary strengthening and precipitation strengthening,the direct-aged sample with dual heterogeneous structures exhibited reduced mechanical heterogeneity,resulting in lowered hetero-deformation-induced hardening.The low strain-hardening capability in the direct-aged sample promoted necking instability while inducing a large Lüders elongation,which effectively improved the tensile ductility.

Progress and development trends in the numerical modeling of solidification

The history of development and current situation of the theoretical description and numerical modeling of the solidification process are reviewed.The status and problems of the related research are discussed,with the main focus being on the solidification theories associated with microstructure formation and the concurrent macro-/microcoupling methods used to simulate solidification.Furthermore,the development trends of the theoretical description and numerical modeling of solidification are discussed.