Resistance index and browning mechanism of apple peel under high temperature stress

Apples are one of the most important economic crops worldwide.Because of global warming and an aggravation of environmental,abnormally high temperatures occur frequently in fruit-growing season and seriously affect normal fruit growth and reduce fruit quality and yield.We took five-year-old Ruixue’(Qinfu 1×Pink Lady;CNA20151469.1) fruits as test materials,and the ambient temperature during fruit development was monitored.The results showed that during the fruit-growing season,especially during the rapid growth stage (July to August),the maximum daily temperature exceeded 30℃ and lasted for more than 40 days.To determine the effects of high temperature stress on the apple fruit resistance,we treated expanding,veraison,and maturity-period fruits at different temperatures.It was found that the fruits of the expanding period showed strong resistance to high temperature stress,whereas during veraison and maturity,fruit resistance to high temperature stress decreased,and the fruit peel browning phenotype appeared.Meanwhile,the content of malonaldehyde (MDA),hydrogen peroxide (H_(2)O_(2)),and superoxide anion (O._(2)^(-)) in the peel gradually increased with increasing temperature.The content of total phenols,flavanol,and flavonoids in the peel decreased substantially at 45℃.Moreover,it was found that polyphenol oxidase gene (MdPPO1) was most sensitive to high temperature stress in apple.Furthermore,transient and stable MdPPO1 overexpression significantly promoted peel browning.The transgenic materials were more sensitive to high temperatures,and browning was more severe compared to non-genetically modified organism (WT).Stable MdPPO1 knockout calli obtained via clustered regularly interspersed short palindromic repeats (CRISPR/Cas9) gene knockout technology reduced the browning phenotype,and the resultant fruits were not sensitive to the effects of high temperature stress.Thus,MdPPO1 expression may be a key factor of high temperature-related changes observed in the browning phenotype that provides a scientific theoretical basis for the selection of high temperature-resistant varieties and apple cultivation and management in the future.

Recent urbanization increases exposure to humid-heat extreme events over populated regions of China

目前对于高温的研究主要侧重于干热,针对湿热的研究相对较少,但它通常会造成更大的社会影响,尤其对人体健康的威胁.已有研究证实,当环境湿球温度超过35℃时,它会破坏人体正常生理代谢,进而威胁人体健康.本研究指出在过去四十年,中国区域日最高湿球温度几乎没有超过35℃,但部分地区日最高湿球温度超过了30℃,主要集中在中国的人口密集区,包括华东,华南和四川盆地等.进一步分析发现,中国区域近期的快速城市化加剧了极端湿热事件的社会影响,城市地区暴露于极端湿热事件的范围的增加速率明显大于其他地区,这也意味着快速城市化使得人口密集区暴露于极端湿热事件的风险明显增加.初步估算指出,自2000年以来,中国区域暴露于极端湿热事件的人口数以每年每天约3100人次的速率显著增加.

A Sharding Scheme Based on Graph Partitioning Algorithm for Public Blockchain

Blockchain technology,with its attributes of decentralization,immutability,and traceability,has emerged as a powerful catalyst for enhancing traditional industries in terms of optimizing business processes.However,transaction performance and scalability has become the main challenges hindering the widespread adoption of blockchain.Due to its inability to meet the demands of high-frequency trading,blockchain cannot be adopted in many scenarios.To improve the transaction capacity,researchers have proposed some on-chain scaling technologies,including lightning networks,directed acyclic graph technology,state channels,and shardingmechanisms,inwhich sharding emerges as a potential scaling technology.Nevertheless,excessive cross-shard transactions and uneven shard workloads prevent the sharding mechanism from achieving the expected aim.This paper proposes a graphbased sharding scheme for public blockchain to efficiently balance the transaction distribution.Bymitigating crossshard transactions and evening-out workloads among shards,the scheme reduces transaction confirmation latency and enhances the transaction capacity of the blockchain.Therefore,the scheme can achieve a high-frequency transaction as well as a better blockchain scalability.Experiments results show that the scheme effectively reduces the cross-shard transaction ratio to a range of 35%-56%and significantly decreases the transaction confirmation latency to 6 s in a blockchain with no more than 25 shards.

The ABA-induced NAC transcription factor MdNAC1 interacts with a bZIP-type transcription factor to promote anthocyanin synthesis in red-fleshed apples

Anthocyanins are valuable compounds in red-fleshed apples.The MdMYB10 transcription factor is an important regulator of the anthocyanin synthesis pathway.However,other transcription factors are key components of the complex network controlling anthocyanin synthesis and should be more thoroughly characterized.In this study,we used a yeast-based screening technology to identify MdNAC1 as a transcription factor that positively regulates anthocyanin synthesis.The overexpression of MdNAC1 in apple fruits and calli significantly promoted the accumulation of anthocyanins.In binding experiments,we demonstrated that MdNAC1 combines with the bZIP-type transcription factor MdbZIP23 to activate the transcription of MdMYB10 and MdUFGT.Our analyses also indicated that the expression of MdNAC1 is strongly induced by ABA because of the presence of an ABRE cis-acting element in its promoter.Additionally,the accumulation of anthocyanins in apple calli co-transformed with MdNAC1 and MdbZIP23 increased in the presence of ABA.Therefore,we revealed a novel anthocyanin synthesis mechanism involving the ABA-induced transcription factor MdNAC1 in red-fleshed apples.

Correction Factors of the Measurement Errors of the LAMOST-LRS Stellar Parameters

We aim to investigate the propriety of stellar parameter errors of the official data release of the LAMOST lowresolution spectroscopy(LRS)survey.We diagnose the errors of radial velocity(RV),atmospheric parameters([Fe/H],Teff,logg)andα-enhancement([α/M])for the latest data release version of DR7,including 6,079,235effective spectra of 4,546,803 stars.Based on the duplicate observational sample and comparing the deviation of multiple measurements to their given errors,we find that,in general,the error of[α/M]is largely underestimated,and the error of RV is slightly overestimated.We define a correction factor k to quantify these misestimations and correct the errors to be expressed as proper internal uncertainties.Using this self-calibration technique,we find that the k-factors significantly vary with the stellar spectral types and the spectral signal-to-noise ratio(S/N).Particularly,we reveal a strange but evident trend between k-factors and error themselves for all five stellar parameters.Larger errors tend to have smaller k-factor values,i.e.,they were more overestimated.After the correction,we recreate and quantify the tight correlations between S/N and errors,for all five parameters,while these correlations have dependence on spectral types.It also suggests that the parameter errors from each spectrum should be corrected individually.Finally,we provide the error correction factors of each derived parameter of each spectrum for the entire LAMOST-LRS DR7 and plan to update them for the later data releases.

LncRNA109897-JrCCR4-JrTLP1b forms a positive feedback loop to regulate walnut resistance against anthracnose caused by Colletotrichum gloeosporioides

Walnut anthracnose induced by Colletotrichum gloeosporioides is a disastrous disease that severely restricts the development of the walnut industry in China.Long non-coding RNAs(lncRNAs)are involved in adaptive responses to disease,but their roles in the regulation of walnut anthracnose resistance response are not well defined.In this study,transcriptome analysis demonstrated that a C.gloeosporioides-induced lncRNA,lncRNA109897,located upstream from the target gene JrCCR4,upregulated the expression of JrCCR4.JrCCR4 interacted with JrTLP1b and promoted its transcriptional activity.In turn,JrTLP1b induced the transcription of lncRNA109897 to promote its expression.Meanwhile,transient expression in walnut leaves and stable transformation of Arabidopsis thaliana further proved that lncRNA,JrCCR4,and JrTLP1b improve the resistance of C.gloeosporioides.Collectively,these findings provide insights into the mechanism by which the lncRNA109897-JrCCR4-JrTLP1b transcriptional cascade regulates the resistance of walnut to anthracnose.

Study on sulphide capacity of CaO-SiO_2-Al_2O_3-MgO-Fe_tO slags

The sulphide capacity of CaO-SiO2-Al2O3-MgO-FetO slags was studied at 1773 K using gas-slag equilibrium techniques. Utilizing a Pt crucible, the slag was equilibrated with a mixture of gases, namely, CO, CO2, SO2 and N2 to provide the partial pressure of oxygen and sulphur. It was shown that at fixed FetO and Al2O3 contents and a fixed { （%CaO）＋（%MgO）}/（%SIO2） ratio, the sulphide capacity decreases with increasing MgO content. At a constant （%CaO）/（%SiO2） ratio and constant MgO and Al2O3 contents, increasing the FetO content of the slags also results in an increase of the sulphide capacity. The rising basicity of （%CaO）/（%SiO2） from 1.0 to 1.4 at fixed MgO, FetO and Al2O3 contents significantly increases the sulphide capacity.

Enrichment of Nb and Ti from carbonatite pyrochlore ore via calcining-slaking followed by gravity separation

In this work,a novel process consisting of calcining-slaking followed by gravity separation for the enrichment of niobium(Nb)and titanium(Ti)from carbonatite pyrochlore ore was proposed,validated and compared with the current mainstream flotation method.During calcining of the pyrochlore ore,within which the carbonates were transformed into lime.Subsequently,when the calcined ore was slaked,lime was transformed into hydroxide with fine particles which were amenable to gravity separation.After calcining at 900℃for 60 min,slaking at 90℃for 10 min with a liquid–solid ratio of 3:1(mL/g),approximately 40%of tailings can be removed by gravity separation,the recoveries of Nb and Ti were 94.7%and 91.0%,and the enrichment ratios of Nb and Ti were 1.61 and 1.43,respectively.The new approach exhibits high separation efficiency of carbonate gangue minerals and valuable minerals,satisfactory recoveries of niobium as well as titanium can be achieved.

Transmission of Terahertz Acoustic Waves through Graphene-Semiconductor Layered Structures

We present a theoretical study of the acoustic properties of graphene-semiconductor layered structures. The transmission coefficient for longitudinal acoustic waves through the structure is evaluated by using the usual transfer matrix method. We find that the finite thickness of the graphene layer can affect significantly the transmission spectrum of the proposed structure. The features of the sound transmittance depend strongly on the number of the graphene layers. For mul-ti-layer graphene-semiconductor structures, the sound transmission spectrum looks very similar to that for an ideal superlattice. For such structures, terahertz acoustic forbidden gap can be observed even when a thick semiconductor layer is considered. These results are the consequence of the Bragg’s condition for sound waves. This study is relevant to the exploration of the acoustic properties of graphene-based layered structures and to the application of graphene as high-frequency acoustic devices.

Research on Linux Kernel Version Diversity for Precise Memory Analysis

The diversity of Linux versions brings challenges to Linux memory analysis,which is an established technique in security and forensic investigations.During memory forensics,kernel data structures are essential information.Existing solutions obtain this information by analyzing debugging information or by decompiling kernel functions to handle a certain range of versions.In this paper,by collecting and analyzing a number of Linux versions,we characterize the properties of different Linux kernel versions and how struct offsets change between versions.Furthermore,the Linux kernel provides over 10,000 configurable features,which leads to different kernel structure layouts for the same kernel version.To deal with this problem,we propose a method of identifying kernel struct layout based on brute-force matching.By examining the relationships between kernel structures,common features are extracted and exploited for brute-force matching.The experimental results show that the proposed technology can deduce structure member offsets accurately and efficiently.

Camouflaging attenuated Salmonella by cryo-shocked macrophages for tumor-targeted therapy

Live bacteria-mediated antitumor therapies mark a pivotal point in cancer immunotherapy.However,the difficulty in reconciling the safety and efficacy of bacterial therapies has limited their application.Improving bacterial tumor-targeted delivery while maintaining biosafety is a critical hurdle for the clinical translation of live microbial therapy for cancer.Here,we developed“dead”yet“functional”Salmonella-loaded macrophages using liquid nitrogen cold shock of an attenuated Salmonella typhimurium VNP20009-contained macrophage cell line.The obtained“dead”macrophages achieve an average loading of approximately 257 live bacteria per 100 cells.The engineered cells maintain an intact cellular structure but lose their original pathogenicity,while intracellular bacteria retain their original biological activity and are delay freed,followed by proliferation.This“Trojan horse”-like bacterial camouflage strategy avoids bacterial immunogenicity-induced neutrophil recruitment and activation in peripheral blood,reduces the clearance of bacteria by neutrophils and enhances bacterial tumor enrichment efficiently after systemic administration.Furthermore,this strategy also strongly activated the tumor microenvironment,including increasing antitumor effector cells(including M1-like macrophages and CD8+Teffs)and decreasing protumor effector cells(including M2-like macrophages and CD4+Tregs),and ultimately improved antitumor efficacy in a subcutaneous H22 tumor-bearing mouse model.The cryo-shocked macrophage-mediated bacterial delivery strategy holds promise for expanding the therapeutic applications of living bacteria for cancer.

基于纳米药物调控肿瘤成纤维样细胞用于肿瘤治疗的研究进展

肿瘤成纤维样细胞是肿瘤间质内数量最多的细胞组分.不同类型实体肿瘤的成纤维样细胞来源有所不同,但均对肿瘤微环境的塑造起到至关重要的作用.其可以大量分泌细胞外基质,促进肿瘤血管新生,阻碍药物输运,阻止免疫细胞的肿瘤浸润,增强肿瘤的化疗及免疫治疗耐受等.因此,针对肿瘤成纤维样细胞促进肿瘤发展的功能进行调控,可重塑肿瘤微环境,提高肿瘤的治疗效果.本文简要介绍了肿瘤成纤维样细胞在肿瘤微环境中的重要作用,并重点介绍基于纳米药物精准调控肿瘤成纤维样细胞的研究进展,为继续开发基于调控肿瘤成纤维样细胞的肿瘤治疗策略提供思路.

A study of the temporal and spatial variations in the suitability of the environment in Chinese cities for tourism and in strategies for optimizing the environment

With the aim of guaranteeing the interests and health of tourists,this study comprehensively evaluates the suitability of the environment in different cities in China for tourism by considering the impacts of climate,vegetation and environmental factors on health.The Universal Thermal Climate Index(UTCI),total precipitation(PREC),Vegetation Leaf Area Index(LAI),concentration of particulate matter with a diameter of less than 2.5μm(PM2.5),and the downward UV radiation at the surface(UVB)are used as indices.In addition,the Delphi–AHP–TOPSIS algorithm is introduced and is used for the comprehensive evaluation of the environmental suitability of 684 cities in China for tourism in 2019.It is found that Chinese cities vary greatly in terms of the suitability of their environments for tourism.Among the factors that affect the environmental suitability,the LAI is important,with an increase in the LAI generally being advantageous.In contrast,an increase in the PM2.5 concentration is a key factor that limits the environmental suitability of an area.Thus,urban landscaping and control of the atmospheric quality are essential and effective ways of improving the suitability of the environment of cities in China for tourists.