Effect of Manganese on DNA-Protein Crosslinks of Testicle in Chicken

In order to explore the effect of manganese on DNA-protein crosslinks （DPC） of testicle in chicken. 500, 800, 1 700 mg·kg^-1 MnC12 were added to forage to establish the model of the sub-chronic manganese poisoning. After 30, 60 and 90 d, testicles were taken out to detect hydroxyl radical inhibiting capacity and DPC content. The results showed that compared with control group, hydroxyl radical inhibiting capacity significantly decreased and DPC content notably increased, and there was a time-dose relationship. It demonstrated that manganese could decrease the inhibitng capacity of hydroxyl radical, increase the content of hydroxyl and DPC, and induce DNA damage.

Mechanical properties of crosslinks controls failure mechanism of hierarchical intermediate filament networks

Intermediate filaments are one of the key components of the cytoskeleton in eukaryotic cells, and their mechanical properties are found to be equally important for physiological function and disease. While the mechanical properties of single full length filaments have been studied, how the mechanical properties of crosslinks affect the mechanical property of the intermediate filament network is not well understood. This paper applies a mesoscopic model of the intermediate network with varied crosslink strengths to investigate its failure mechanism under the extreme mechanical loading. It finds that relatively weaker crosslinks lead to a more flaw tolerant intermediate filament network that is also 23% stronger than the one with strong crosslinks. These findings suggest that the mechanical properties of interfacial components are critical for bioinspired designs which provide intriguing mechanical properties.

Achieving High CO_(2)Photoreduction Activity by Conductive Crosslinks of Metal–Organic Framework

Fast photogenerated charge migration is crucial for the improvement of photocatalytic performance,but its deliberate modulation is difficult.This work presents two Zr-based metal–organic framework catalysts,GDUT-8 and GDUT-8-Ox,for photocatalytic CO_(2)reduction.Specifically,thiophene pendants in GDUT-8 were coupled covalently via Scholl reaction to give GDUT-8-Ox,a catalyst with at least two orders of magnitude(up to 6.1×10^(−3)S cm^(−1))enhanced conductivity and faster transport of photogenerated carriers during photocatalysis.Furthermore,from GDUT-8 to GDUT-8-Ox,stronger ligand-to-cluster charge transfer with pronounced light absorption extension was observed.As a result,GDUT-8-Ox exhibited the highest photocatalytic CO_(2)-to-HCOO−conversion rate(1725μmol g^(−1)h^(−1))to date,in the absence of photosensitizer,as well as turnover number,turnover frequency,and quantum efficiency much higher than GDUT-8.This work presents an unprecedented strategy to accelerate the photogenerated carrier transport of photocatalysts.

Supramolecular photoresponsive polyurethane with movable crosslinks based on photoisomerization of azobenzene

Light-driven actuators are widely used for smart devices such as soft robots.One of the main challenges for actuators is achieving rapid responsiveness,in addition to ensuring favorable mechanical properties.Herein,we focused on photoresponsive polyurethane(CD-Azo-PU)based on controlling the crystallization of the hard segments in polyurethane(PU)by complexation between azobenzene(Azo)and cyclodextrins(CDs).CD-Azo-PU incorporated polyurethane as the main chain and a 1:2 inclusion complex between Azo andγCD as a movable crosslink point.Upon ultraviolet light(UV,λ=365 nm)irradiation,the photoresponsiveness of CD-Azo-PU bent toward the light source(defined as positive),while that of the linear Azo polyurethane(Azo-LPU)without peracetylatedγ-cyclodextrin diol(TAcγCD-diOH)as a movable crosslinker bent in the direction opposite the light source.The bending rates were determined to be 0.25°/s for CD-Azo-PU and 0.083◦/s for Azo-LPU,indicating that the bending rate for CD-Azo-PU was faster than that for Azo-LPU.By incorporating movable crosslinks into CD-Azo-PU,we successfully achieved specific photoresponsive actuation with an enhanced rate.

Quantitative and structural analysis of isotopically labelled natural crosslinks in type I skin collagen using LC-HRMS and SANS

Collagen structure in biological tissues imparts its intrinsic physical properties by the formation of several covalent crosslinks.For the first time,two major crosslinks in the skin dihydroxylysinonorleucine(HLNL)and histidinohydroxymerodesmosine(HHMD),were isotopically labelled and then analysed by liquid-chromatography high-resolution accurate-mass mass spectrometry(LC-HRMS)and small-angle neutron scattering(SANS).The isotopic labelling followed by LC-HRMS confirmed the presence of one imino group in both HLNL and HHMD,making them more susceptible to degrade at low pH.The structural changes in collagen due to extreme changes in the pH and chrome tanning were highlighted by the SANS contrast variation between isotopic labelled and unlabelled crosslinks.This provided a better understanding of the interaction of natural crosslinks with the chromium sulphate in collagen suggesting that the development of a benign crosslinking method can help retain the intrinsic physical properties of the leather.This analytical method can also be applied to study artificial crosslinking in other collagenous tissues for biomedical applications.

The flow behavior of droplet adsorption on a liquid-liquid interface accompanied by cross-linking reaction and phase separation in a microchannel

The adsorption process of droplets on the liquid-liquid interface and phase separation process can regulate the spatial distribution of the fluid system,which are crucial for chemical engineering.However,the cross-linking reaction,which is widely used in the field of polymers,can change the physical properties of the fluids and affect the flow behavior accordingly.A configuration of microchannels is designed to conveniently generate uniform droplets in one phase of the parallel flow.The flow behavior of the adsorption process of sodium alginate droplets on the liquid-liquid interface is investigated,and the subsequent process of phase separation is studied.In the process of droplet adsorption,the crosslinking reaction occurs synchronously,which makes the droplet viscosity and the elasticity modules of the droplet surface increase,thus affecting the dynamics of the adsorption process and the equilibrium shape of the droplet.The variation of the adsorption length with time is divided into three stages,which all conform to power law relationship.The exponents of the second and third stages deviate from the results of the Tanner's law.The flow pattern maps of droplet adsorption and phase separation are drawn,and the operating ranges of complete adsorption and complete separation are provided.This study provides a theoretical basis for further studying the flow behavior of droplets with cross-linking reaction in a microchannel.

B-COPNA resin formation from ethylene tar light fractions:Process development and mechanical exploration by molecular simulation

An efficient utilization strategy of ethylene tar(ET),the main by-product of the ethylene cracking unit,is urgently required to meet demands for modern petrochemical industry.On the other hand,condensed polynuclear aromatic resin of moderate condensation degree(B-COPNA)is a widely used carbon material due to its superb processability,the production of which is,however,seriously limited by the high cost of raw materials.Under such context,an interesting strategy was proposed in this study for producing B-COPNA resin using crosslinked light fractions of ethylene tar(ETLF,boiling point<260℃)facilitated by molecular simulation.1,4-Benzenedimethanol(PXG)was first selected as the crosslinking agent according to the findings of molecular simulation.The effects of operating conditions,including reactions temperature,crosslinking agent,and catalyst content on the softening point and yield of B-COPNA resin products were then investigated to optimize the process.The reaction mechanism of resin production was studied by analyzing the molecular structure and transition state of ETLF and crosslinking agents.It was shown that PXG exhibited a superior capacity of withdrawing electrons and a higher electrophilic reactivity than other crosslinking agents.In addition to the highest yield and greatest heat properties,PXG-prepared resin contained the most condensed aromatics.The corresponding optimized conditions of resin preparation were 180℃,1:1.9(PXG:ETLF),and 3%(mass)of catalyst content with a resin yield of 78.57%.It was the electrophilic substitution reaction that occurred between the ETLF and crosslinking agent molecules that were responsible for the resin formation,according to the experimental characterization and molecular simulation.Hence,it was confirmed that the proposed strategy and demonstrated process can achieve a clean and high value-added utilization of ETLF via B-COPNA resin preparation,bringing huge economic value to the current petrochemical industry.

Detecting early changes in choroidal vascularity and thickness using optical coherence tomography in patients with corneal crosslinking for keratoconus

AIM:To investigate changes in choroidal thickness and vascularity in keratoconus patients treated with corneal crosslinking.METHODS:This study evaluated 28 eyes of 22 patients with keratoconus who underwent corneal crosslinking.The choroidal thicknesses were evaluated on enhanced depth imaging optical coherence tomography at the preoperative and postoperative 3d,1,and 3mo.Choroidal thickness in the four cardinal quadrants and the fovea were evaluated.The choroidal vascularity index was also calculated.RESULTS:There was no significant difference in central choroidal thickness between the preoperative and postoperative 3d,1mo(P>0.05).There was a significant increase in the 3mo(P=0.034)and a significant decrease in the horizontal choroidal vascularity index on the postoperative 3d(P=0.014),there was no statistically significant change in vertical axes and other visits in horizontal sections(P>0.05).CONCLUSION:This study sheds light on choroidal changes in postoperative corneal crosslinking for keratoconus.While it suggests the procedure’s relative safety for submacular choroid,more extensive research is necessary to confirm these findings and their clinical significance.

Stromal lenticule addition keratoplasty with corneal crosslinking for corneal ectasia secondary to FS-LASIK:a case series

●AIM:To explore the clinical efficacy and safety of stromal lenticule addition keratoplasty(SLAK)with corneal crosslinking(CXL)on patients with corneal ectasia secondary to femtosecond laser-assisted in situ keratomileusis(FS-LASIK).●METHODS:A series of 5 patients undertaking SLAK with CXL for the treatment of corneal ectasia secondary to FS-LASIK were followed for 4-9mo.The lenticules were collected from patients undertaking small incision lenticule extraction(SMILE)for the correction of myopia.Adding a stromal lenticule was aimed at improving the corneal thickness for the safe application of crosslinking and compensating for the thin cornea to improve its mechanical strength.●RESULTS:All surgeries were conducted successfully with no significant complications.Their best corrected visual acuity(BCVA)ranged from 0.05 to 0.8-2 before surgery.The pre-operational total corneal thickness ranged from 345-404μm and maximum keratometry(Kmax)ranged from 50.8 to 86.3.After the combination surgery,both the corneal keratometry(range 55.9 to 92.8)and total corneal thickness(range 413-482μm)significantly increased.Four out of 5 patients had improvement of corneal biomechanical parameters(reflected by stiffness parameter A1 in Corvis ST).However,3 patients showed decreased BCVA after surgery due to the development of irregular astigmatism and transient haze.Despite the onset of corneal edema right after SLAK,the corneal topography and thickness generally stabilized after 3mo.●CONCLUSION:SLAK with CXL is a potentially beneficial and safe therapy for advanced corneal ectasia.Future work needs to address the poor predictability of corneal refractometry and compare the outcomes of different surgical modes.

Biomimetic fibril-like injectable hydrogels for wound management

Soft tissue repair and regeneration present a significant clinical challenge.Soft hydrogels have emerged as a promising solution for promoting stem cell differentiation and facilitating soft tissue formation[1].Various materials,including synthetic polymers like polydimethyl siloxane and natural polymers like proteins,have been be used as hydrogel matrix for hydrogel preparation[2,3].However,the limited biodegradability,inhomogeneous network structure,and inadequate mechanical properties of these hydrogels hinder their long-term application in complex environments in vivo.Inspired by the nanostructure of collagen fibrils,Li et al.developed a strategy for creating injectable nanofibrillar hydrogels by combining self-assembly and chemical crosslinking of nanoparticles[4].Moreover,injectable hydrogels offer advantages as implantable materials,including better defect filling and reduced risk of infection compared to prefabricated hydrogels[5].

Homologous recombination in DNA repair and DNA damage tolerance

Homologous recombination （HR） comprises a series of interrelated pathways that function in the repair of DNA double-stranded breaks （DSBs） and interstrand crosslinks （ICLs）. In addition, recombination provides critical support for DNA replication in the recovery of stalled or broken replication forks, contributing to tolerance of DNA damage. A central core of proteins, most critically the RecA homolog Rad51, catalyzes the key reactions that typify HR： homology search and DNA strand invasion. The diverse functions of recombination are reflected in the need for context-specific factors that perform supplemental functions in conjunction with the core proteins. The inability to properly repair complex DNA damage and resolve DNA replication stress leads to genomic instability and contributes to cancer etiology. Mutations in the BRCA2 recombination gene cause predisposition to breast and ovarian cancer as well as Fanconi anemia, a cancer predisposition syndrome characterized by a defect in the repair of DNA interstrand crosslinks. The cellular functions of recombination are also germane to DNA-based treatment modalities of cancer, which target replicating cells by the direct or indirect induction of DNA lesions that are substrates for recombination pathways. This review focuses on mechanistic aspects of HR relating to DSB and ICL repair as well as replication fork support.

新型壳聚糖用于地下水中Pb^(2+)的吸附性能研究

利用聚乙二醇(PEG400)作为交联剂合成的壳聚糖材料,探讨Pb2+印迹量对吸附效果的影响,通过吸附动力学,吸附等温线等方面的研究,讨论其吸附的内在机理。研究表明印迹Pb2+质量占PEG-CTS质量4%的交联壳聚糖,去除率最高;吸附遵循准二级动力学模型,吸附速率为0.272 2 mg.g-1.h-1;在20℃,溶液pH为7的条件下,PEG-CTS对Pb2+的最大吸附容量为20.20 mg/g,平均吸附能量为13.12 kJ/mol;化学吸附为主。关键词:交联壳聚糖;聚乙二醇;地下水;Pb2+;

三乙醇胺含量的气相色谱测定法

以 HP- INNOWAX(Crosslinked Polyethlene Glycol交链聚乙二醇 )毛细管柱为固定相 ,氢火焰离子化检测器 (FID) ,二阶程序升温 ,碳酸乙烯酯为内标气相色谱法分析工业三乙醇胺的含量。检出限为10 ng,相对标准偏差均小于 2 .13% ,回收率在 96 .12 %— 10 2 .6 3%之间 ,方法操作简便 ,灵敏 ,准确、重现性好 ,适用于三乙醇胺的质量分析。

Design of Medical Devices Using Spongy Sheet Composed of Hyaluronic Acid and Collagen

This research aims to obtain useful information for development of medical devices such as wound dressing and tissue anti-adhesive product, using a spongy sheet composed of hyaluronic acid (HA) and collagen (Col). The spongy sheets were manufactured by freeze vacuum drying of HA and Col aqueous solution, followed by UV irradiation to introduce intermolecular crosslinks between Col molecules. These spongy sheets are referred to as Sponge-A (ratio of HA/Col = 5/1) and Sponge-B (ratio of HA/Col = 5/5). Both surfaces of Sponge-A and Sponge-B treated with UV irradiation for 15 minutes are referred to as Sponge-A-15 and Sponge-B-15, respectively. The weight change of spongy sheet was determined by immersing a peace of spongy sheet in water at 37°C. The weight of sponge-A-15 collected 1/2, 1, 3, 7 days after immersion in water was 63.5%, 62.1%, 56.6%, 54.4% of the original weight, respectively. The weight of Sponge-B-15 was 78.3%, 76.7%, 79.1%, 71.9% of the original weight, respectively. The weight change of spongy sheet was determined by immersing a peace of spongy sheet in water containing collagenase at 37°C. The weight of Sponge-A-15 collected 6, 8, 10, 12 hours after immersion in water containing collagenase (0.0005 w/v%) was 65.7%, 59.8%, 57.9%, 55.2% of the original weight, respectively. The weight of Sponge-B-15 was 63.5%, 52.1%, 42.0%, 43.2% of the original weight, respectively. This spongy sheet is considered to have the unique structure, where HA molecules are entrapped in an intermolecular cross-linked network structure of Col molecules. When immersed in water containing collagenase, the weight loss of spongy sheet is accelerated by easy extraction of HA molecules from the enzymatic degraded Col network structure. The performance of wound dressing and tissue anti-adhesive product is considered to depend on appropriate ratio of HA and Col, and also on appropriate rate of intermolecular crosslinks between Col molecules. These findings obtained in this study provide useful information for product development such as wound dressing and tissue anti-adhesive product.

Heuristics Scheduling Algorithm on the Links Scheduling of Satellite-Ground Clock Synchronization and Ephemeris Uploading in COMPASS System

The execution process of satellite-ground clock synchronization and ephemeris uploading in the system is analyzed,as well as their characterized operation and their relationship.Based on the analysis of the scheduling goal and constraint character,a heuristics rule-based multi-stage link scheduling algorithm was put forward.The algorithm distinguishes the on-off-frontier satellites from the others and schedules them by turns.The paper presented the main flow as well as the detailed design of the rule.Finally based on the current COMPASS global system,some typical resources and constraints are selected to generate an instance.Then the comparison analysis between the heuristics scheduling algorithm and three other traditional scheduling strategies are carried out.The result shows the validity and reasonability of the multi-stage strategy.

<i>In Vitro</i>Investigation of DNA Damage Induced by the DNA Cross-Linking Agents Oxaliplatin and Satraplatin in Lymphocytes of Colorectal Cancer Patients

Exposure to toxic chemicals, especially chemotherapeutic drugs, may induce several DNA lesions, including DNA interstrand crosslinks. These crosslinks are considered toxic lesions to the dividing cells since they can induce mutations, chromosomal rearrangements, and cell death. Many DNA interstrand crosslinks lesions can be generated by platinum-based chemotherapeutic agents. Satraplatin is a novel orally administered platinum-based chemotherapeutic agent. In the present study, we investigated DNA interstrand crosslinks lesions induced by oxaliplatin and satraplatin in lymphocytes obtained from colorectal cancer patients and healthy volunteers. Satraplatin demonstrated an increase in interstrand crosslinks in a dose-dependent manner in the Comet assay (p in vitro. Here, to the best of our knowledge we report for the first time evidence of DNA double strand breaks formation as a possible molecular mechanism of action for satraplatin.

Metal cation crosslinking of Ti O_2-alginate hybrid gels

In order to improve the substrate diffusion properties and stability of an immobilized enzyme alginate microgels modified with TiO2 nanoparticles were employed as the enzyme immobilizing support.Ionotropic gelation was applied for the preparation of hybrid gels while Ca2＋ Ce3＋ Ni2＋Cu2＋and Fe3＋were employed as the crosslinkers.Papain was selected as the model enzyme. UV-Vis spectroscopy was employed to investigate the activity of papain to evaluate kinetics and stability.Analysis results show that the highest affinity the lowest Michaelis-Menten constant Km =11.0 mg/mL and the highest stability are obtained when using Cu2＋as the crosslinker.The effect of the mass ratio of TiO2 to papain on the stability and leakage of papain is also investigated and the results show that 10∶1 TiO2∶papain is optimal because the proper use of TiO2 can reduce enzyme leakage and ensure enzyme stability.Preparing Cu/alginate/TiO2 hybrid gels via ionotropic gelation can provide a satisfactory diffusion capability and enzyme stability.

基于FPGA的实时MIPI CSI-2图像采集与处理系统

针对目前移动嵌入式领域中广泛使用的MIPI CSI-2接口,设计了一种基于Lattice FPGA的实时图像采集与处理系统,实现了高清图像采集、Bayer格式转换、图像缩放、图像倒置和饱和度调整等多种功能。通过对系统进行功能验证与测试,表明系统可以稳定地采集1080p60的图像数据,并完成相关的图像处理功能,具有一定的实用价值。相对于其他平台,采用FPGA具有实时性高,功耗和成本低以及系统升级方便等优势。

Study on Tribological Properties of Irradiated Crosslinking UHMWPE Nano-Composite

Ultra High Molecular Weight Polyethylene(UHMWPE)has been widely used as a bearing material for artificial joint replacement over forty years.It is usually crosslinked by gamma rays irradiation before its implantation into human body.In this study,UHMWPE and UHMWPE/nano-hydroxyapatite(n-HA)composite were prepared by vacuum hot-pressing method.The prepared materials were irradiated by gamma rays in vacuum and molten heat treated in vacuum just after irradiation.The effect of filling n-HA with gamma irradiation on tribological properties of UHMWPE was investigated by using friction and wear experimental machine(model MM-200)under deionized water lubrication.Micro-morphology of worn surface was observed by metallographic microscope.Contact angle and hardness of the materials were also measured.The results show that contact angle and hardness are changed by filling n-HA and gamma irradiation.Friction coefficient and wear rate under deionized water lubrication are reduced by filling n-HA.While friction coefficient is increased and wear rate is reduced significantly by gamma irradiation.The worn surface of unfilled material is mainly characterized as adhesive wear and abrasive wear,and that of n-HA filled material is mainly characterized as abrasive wear.After gamma irradiation,the degrees of adhesive and abrasive wear for unfilled material and abrasive wear of n-HA filled material are significantly reduced.Unfilled and filled materials after irradiation are mainly shown as slight fatigue wear.The results indicate that UHMWPE and UHMWPE/n-HA irradiated at the dose of 150 kGy can be used as bearing materials in artificial joints for its excellent wear resistance compared to original UHMWPE.

Interfacial assembly of two-dimensional MXenes

Two-dimensional(2D) transition metal carbides, carbonitrides and nitrides, known as MXenes, are emerging quickly at the frontiers of 2D materials world. Their exotic properties such as the highest electrical conductivity among all solution-processed 2 D materials, the best electromagnetic interference shielding performance outperforming that of copper or aluminum at a nanoscale thickness, as well as the highest volumetric capacitance for pseudocapacitors, have been attracting extensive fundamental research and applications. Their unique surface chemistries, that is, hydrophilic groups terminated on the surface of MXenes after etching and delamination, enable plenty of opportunities for assembling into MXene building blocks. Particularly, assembling at liquid–liquid, liquid–solid, liquid–air, and solid–solid interfaces allows the efficient fabrication of various structures, including MXene surfactants, MXene heterostructures, MXene transparent films. Interfacial assembly of MXenes is of significance in unveiling more versatilities of MXenes as well as impacts on novel MXene-based architectures, based on which enhanced performance of devices is achieved. As such, this review focuses on the interfacial assembly of MXenes, explaining mechanisms behind various assembling and providing classical examples for corresponding interfacial assembling techniques. Applications of these as-assembled architectures are also discussed in brief. We believe this review may shed light on the interfacial chemistry of MXenes, thus guiding more efficient fabrication of MXene-based functional films/coatings/electrodes/devices.