Smart Colorimetric Corn Starch Films Combined with Anthocyanin-Loaded Glutenin-Carboxymethyl Chitosan Nanocomplexes for Freshness Monitoring of Chilled Pork

In this study,intelligent,pH-responsive colorimetric films were prepared by encapsulating anthocyanins in nanocomplexes prepared from glutenin and carboxymethyl chitosan.These nanocomplexes were added to a corn starch matrix and used in the freshness monitoring of chilled pork.The effects of anthocyanin-loaded nanocomplexes on the physical,structural,and functional characteristics of the films were investigated.The addition of anthocyanin-loaded nanocomplexes increased the tensile strength,elongation at break,hydrophobicity,and light transmittance of the films while decreasing their water vapor permeability.This is because new hydrogen bonds are formed between the film components,resulting in a more homogeneous and dense structure.The colorimetric film has a significant color response to pH changes.These films were used in experiments on the freshness of chilled pork,in which the pH changes with changing freshness states.The results show that the colorimetric film can monitor changes in the freshness of chilled pork in real time,where orange,pink,and green represent the fresh,secondary fresh,and putrefied states of pork,respectively.Therefore,the intelligent colorimetric film developed in this study has good application potential in the food industry.

利用废弃聚对苯二甲酸乙二醇酯制备共聚酯PBCAT

聚对苯二甲酸乙二醇酯(PET)凭借其优异的综合性能被广泛用于包装行业,但PET在自然条件下难以降解,极易造成环境污染。为缓解该问题,文中对废弃PET进行解聚回收并将产物转化为新型可生物降解共聚酯。首先确定了以丁二醇(1,4-BDO)为醇解剂的最佳醇解条件,PET的解聚率可达99%,醇解产物的实际产率可达理论产率的80%。借助红外光谱、核磁共振及液相-质谱联用仪(LC-MS)等,证明醇解产物主要是对苯二甲酸丁二醇酯及少量的二聚、三聚体(记为BHBT)。分别以醇解产物BHBT及对苯二甲酸(PTA)为原料制备了新型共聚酯——聚对苯二甲酸己二酸-丁二醇环己烷二甲醇酯(分别记为rPBCAT和PBCAT);分析对比了rPBCAT和PBCAT的结构及性能,发现BHBT可以替代PTA参与共聚反应,rPBCAT具有与PBCAT相同的化学结构,rPBCAT具有同样优良的热性能和力学性能,其T-5%为344.2℃,拉伸强度为9.98 MPa,断裂伸长率达726.7%。综上表明,废弃PET可成功回收并转化为高附加值的新型共聚酯,为解决非降解型聚酯的白色污染提供了新途径,具有显著的经济和社会价值。

Identification and expression analysis of chlorogenic acid biosynthesis key gene PpHCT in peach

Shikimic acid/quinic acid hydroxy cinnamyl transferase(HCT)is one of the key enzymes in the phenylpropanoid pathway.However,the role of the HCT gene in chlorogenic acid(CGA)biosynthesis in peach fruit remains unclear.For this,we identified the accumulation pattern of CGA in four peach cultivars,cloned and characterized 11 PpHCT gene members,and further analyzed the expression patterns of these PpHCT genes during fruit development.The contents of CGAs in the four peach cultivars all exhibited a trend of increasing and then decreasing during the fruit growth and development.Moreover,the contents of CGAs in the peel and flesh were tissue-specific.Gene structure analysis indicated that the PpHCT genes were highly conserved,containing two exons and one intron.The protein structure analysis demonstrated that the PpHCT proteins contained two conserved motifs(HXXXD,DFGWG)and a transferase domain(PF02458),which belonged to the BAHD acyltransferase family.The cis-acting element analysis suggested that the promoters of PpHCT genes contained many light-related,hormone-related,stress-related,tissue-specific,and circadian-related elements,and they could participate in a variety of biological processes.Phylogenetic analysis showed that the HCT proteins of peach were closely related to the HCT proteins of plum and had a close evolutionary relationship.The qRT-PCR analysis indicated that the expression levels of PpHCT1 and PpHCT2 showed an opposite trend to the accumulation of CGA,whereas the expression levels of PpHCT4,PpHCT5,PpHCT7,PpHCT8,and PpHCT11 demonstrated the same trend as CGA accumulation.It was worth noting that only PpHCT4 and PpHCT5 were highly expressed in the two high-CGA cultivars but showed low levels of expression in the two low-CGA cultivars.Therefore,it was hypothesized that these two genes might be key genes to the synthesis of CGA in peach fruit.Those findings provide a theoretical basis for further study on the biological functions of the HCT gene and help to reveal the molecular mechanism of CGA.

Development, Application and Prospect of Dissolving Microneedles

In recent years, as a new transdermal drug delivery method, microneedle transdermal drug delivery technology accelerates the absorption of drugs through micron pores, which has been widely used in the field of medicine and cosmetics. Dissolving microneedles have the characteristics of good biocompatibility and fast dissolution speed, which attract more and more researchers’ attention and research. In this paper, the concept, properties and preparation methods of dissolving microneedles as well as the research status of dissolving microneedles in the field of medicine and cosmetics in recent years were summarized and prospected, so as to enable researchers to have a clearer and comprehensive understanding of dissolving microneedles and prospect the application and development prospects of dissolving microneedles in the industry.

聚氨酯类锚固剂的合成及对软质聚氯乙烯的改性

使用自制的中低相对分子质量的热塑性聚氨酯(TPU)齐聚物"锚固剂"(AA),可将增塑剂分子"锚固"在聚氯乙烯(PVC)基体上,从而改善PVC的迁移析出性能和低温性能。通过凝胶渗透色谱、红外光谱、差示扫描量热分析和动态力学热分析表征了自制的"锚固剂"(AA)。通过扫描电镜、动态力学热分析、高低温力学性能以及高低温迁移析出性能测试,研究了AA与PVC的相容性以及对软质PVC性能的影响。结果表明,AA与PVC可互容,AA用量至60 phr,-30℃时软质PVC的断裂伸长率保留率提高了280%倍左右,-10℃时温度敏感指数下降了44%,迁移析出率下降了72%。相同增塑剂含量下,DOTP/AA复合体系与纯DOTP相比,-30℃时的温度敏感指数仅为后者的24%,-10℃时的迁移析出率仅为后者的5%左右。

Light induces petal color change in Quisqualis indica(Combretaceae)

Petal color change, a common phenomenon in angiosperms, is induced by various environmental and endogenous factors. Interestingly, this phenomenon is important for attracting pollinators and further reproductive success. Quisqualis indica L.(Combretaceae) is a tropical Asian climber that undergoes sequential petal color change from white to pink to red. This color changing process is thought to be a good strategy to attract more pollinators. However, the underlying physiological and biochemical mechanisms driving this petal color change phenomenon is still underexplored. In this context, we investigated whether changes in pH, pollination, light, temperature or ethylene mediate petal color change. We found that the detected changes in petal pH were not significant enough to induce color alterations. Additionally, pollination and temperatures of 20-30℃did not alter the rate of petal color change; however, flowers did not open when exposed to constant temperatures at 15℃ or 35℃.Moreover, the application of ethylene inhibitor, i.e., silver thiosulphate, did not prevent color change. It is worth mentioning here that in our study we found light as a strong factor influencing the whole process of petal color change, as petals remained white under dark conditions. Altogether, the present study suggests that petal color change in Q. indica is induced by light and not by changes in petal pH, pollination, ethylene, or temperature, while extremely low or high temperatures affect flower anthesis. In summary, our findings represent the probable mechanism underlying the phenomenon of petal color change, which is important for understanding flower color evolution.

Research on Workpiece Sorting System Based on Machine Vision Mechanism

This paper describes industrial sorting system, which is based on robot vision technology, introduces main image processing methodology used during development, and simulates algorithm with Matlab. Besides, we set up image processing algorithm library via C# program and realize recognition and location for regular geometry workpiece. Furthermore, we analyze camera model in vision algorithm library, calibrate the camera, process the image series, and resolve the identify problem for regular geometry workpiece with different colours.

DXF File Identification with C# for CNC Engraving Machine System

This paper researches the main technology of open CNC engraving machine, the DXF identification technology. Agraphic information extraction method is proposed. By this method, the graphic information in DXF file can be identified and transformed into bottom motion controller’s code. So the engraving machine can achieve trajectory tracking. Then the open CNC engraving machine system is developed with C#. At last, the method is validated on a three axes motion experiment platform. The result shows that this method can efficiently identify the graphic information including line, circle, arc etc. in DXF file and the CNC engraving machine can be controlled well.

Gene regulation of anthocyanin biosynthesis in two blood-flesh peach （Prunus persica （L.） Batsch） cultivars during fruit development

The blood-flesh peach has become popular in China due to its attractive anthocyanin-induced pigmenta- tion and antioxidant properties. In this study, we investigated the molecular mechanisms underlying anthocyanin accumulation by examining the expression of nine genes of the anthocyanin biosynthesis pathway found in the peach mesocarp. Expression was measured at six developmental stages in fruit of two blood-flesh and one white-flesh peach cultivars, using quantitative reverse transcription polymerase chain reaction （qRT-PCR）. Results show that the expression of the chalcone synthase （CHS） gene was closely related to anthocyanin accumulation in both of the blood-flesh peaches. In the white-flesh peach, we found that the transcription level of phenylalanine ammonia-lyase （PAL） during fruit development was much lower than that in the blood-flesh peach, even though all other genes of the anthocyanin biosynthesis pathway were highly expressed, suggesting that the PAL gene may be limiting in antho- cyanin production in the white-flesh peach. Moreover, the transcription levels of the CHS and UDP-glucose-flavonoid 3-O-glucosyltransferase （UFGT） genes were markedly up-regulated at three days after bag removal （DABR） in the blood-flesh peach, suggesting that CHS and UFGT are the key genes in the process of anthocyanin biosynthesis for both of the blood-flesh peaches. The present study will be of great help in improving understanding of the molecular mechanisms involved in anthocyanin accumulation in blood-flesh peaches.

Development of ratiometric DNA biosensors with improved accuracy,precision,and signal-to-noise ratio

Ratiometric DNA biosensors,which utilize DNA as the recognition element and integrate dual signals from diverse sensing platforms including fluorescence,electrochemistry,and surface-enhanced Raman scattering(SERS),have demonstrated remarkable proficiency in detecting a wide range of targets.In this review,we showcase the significant progress achieved by ratiometric biosensors.Firstly,ratiometric biosensors have made notable advancements in analyzing real samples.These include the analysis of pH values near cancer cells,quantification of miRNA in human cell lysates,detection of human telomerase RNA in cell extracts,and performing DNA logicgated in situ bioimaging on cell membranes.Secondly,excellent sensitivity has been attained through the utilization of effective amplification methods such as RCA,HCR,and CHA,among others.Thirdly,the construction of stable reference signals has resulted in significantly improved precision for ratiometric biosensors.This breakthrough has overcome matrix effects,enabling reliable detection in real samples with high selectivity.This review provides a comprehensive overview of recent advancements in strategies employed by ratiometric DNA biosensors.We present three types of biosensors based on distinct sensing platforms:fluorescent,electrochemical,and SERS biosensors.Additionally,we discuss future directions and primary challenges in the development of ratiometric DNA biosensors.

Bimetallic nano-mushrooms with DNA-mediated interior nanogaps for high-efficiency SERS signal amplification

Uniform silver-containing metal nanostructures with well-defined nanogaps hold great promise for ultrasensitive surface-enhanced Raman scattering （SERS） analyses. Nevertheless, the direct synthesis of such nanostructures with strong and stable SERS signals remains extremely challenging. Here, we report a DNA-mediated approach for the direct synthesis of gold-silver nano-mushrooms with interior nanogaps. The SERS intensities of these nano-mushrooms were critically dependent on the area of the nanogap between the gold head and the silver cap. We found that the formation of nanogaps was finely tunable by controlling the surface density of 6-carboxy-X-rhodamine （ROX） labeled single-stranded DNA （ssDNA） on the gold nanoparticles. We obtained nano-mushrooms in high yield with a high SERS signal enhancement factor of -1.0×109, much higher than that for Au-Ag nanostructures without nanogaps. Measurements for single nano- mushrooms show that these structures have both sensitive and reproducible SERS signals.

A Nano-and Micro-Integrated Protein Chip Based on Quantum Dot Probes and a Microfluidic Network

A novel nano-and micro-integrated protein chip(NMIPC)that can detect proteins with ultrahigh sensitivity has been fabricated.A microfl uidic network(μFN)was used to construct the protein chips,which allowed facile patterning of proteins and subsequent biomolecular recognition.Aqueous phase-synthesized,water-soluble fl uorescent CdTe/CdS core-shell quantum dots(aqQDs),having high quantum yield and high photostability,were used as the signaling probe.Importantly,it was found that aqQDs were compatible with microfluidic format assays,which afforded highly sensitive protein chips for cancer biomarker assays.

Programming of Regulatory T Cells In Situ for Nerve Regeneration and Long-Term Patency of Vascular Grafts

Rapid integration into the host tissue is critical for long-term patency after small diameter tissue engineering vascular grafts(sdTEVGs)transplantation.Neural recognition may be required for host integration and functionalization of the graft.However,immune rejection and inflammation hinder nerve regeneration of sdTEVGs.Here,a CRISPR/dCas9-nanocarrier was used for targeted programming of regulatory T cells(Treg cells)in situ to promote nerve regeneration of sdTEVGs by preventing excessive inflammation.Treg cells and(C-C chemokine receptor)CCR2+macrophage recruitment occurred after transplantation.The nanodelivery system upregulated ten eleven translocation(TET2)in Treg cells in vitro.Reprogrammed Treg cells upregulated anti-inflammatory cytokines and decreased the proportion of CCR2+macrophages.IL-6 concentrations decreased to the levels required for nerve regeneration.Implantation of CRISPR/dCas9 nanodelivery system-modified sdTEVGs in rats resulted in Treg cell editing,control of excessive inflammation,and promoted nerve regeneration.After 3 months,nerve regeneration was similar to that observed in normal blood vessels;good immune homeostasis,consistency of hemodynamics,and matrix regeneration were observed.Neural recognition promotes further integration of the graft into the host,with unobstructed blood vessels without intimal hyperplasia.Our findings provide new insights into vascular implant functionalization by the host.

Population transcriptomics reveals a potentially positive role of expression diversity in adaptation

While it is widely accepted that genetic diversity determines the potential of adaptation,the role that gene expression variation plays in adaptation remains poorly known.Here we show that gene expression diversity could have played a positive role in the adaptation of Miscanthus lutarioriparius.RNA-seq was conducted for 80 individuals of the species,with half planted in the energy crop domestication site and the other half planted in the control site near native habitats.A leaf reference transcriptome consisting of 18,503 high-quality transcripts was obtained using a pipeline developed for de novo assembling with population RNA-seq data.The population structure and genetic diversity of M.lutarioriparius were estimated based on 30,609 genic single nucleotide polymorphisms.Population expression（Ep） and expression diversity（Ed）were defined to measure the average level and the magnitude of variation of a gene expression in the population,respectively.It was found that expression diversity increased while genetic Resediversity decreased after the species was transplanted from the native habitats to the harsh domestication site,especially for genes involved in abiotic stress resistance,histone methylation,and biomass synthesis under water limitation.The increased expression diversity could have enriched phenotypic variation directly subject to selections in the new environment.

Some Results on Graph Products Determined by Their Spectra

In this paper, we prove that some Kronecker products of G and K2 are determined by their spectra where the graph G is also determined by its spectrum. And a problem for further researches is proposed.