Magnetic Particle Imaging for Magnetic Hyperthermia Treatment: Visualization and Quantification of the Intratumoral Distribution and Temporal Change of Magnetic Nanoparticles in Vivo

Purpose: Magnetic hyperthermia treatment (MHT) is a strategy for cancer therapy using the tem-perature rise of magnetic nanoparticles (MNPs) under an alternating magnetic field (AMF). Re-cently, a new imaging method called magnetic particle imaging (MPI) has been introduced. MPI allows imaging of the spatial distribution of MNPs. The purpose of this study was to investigate the feasibility of visualizing and quantifying the intratumoral distribution and temporal change of MNPs and predicting the therapeutic effect of MHT using MPI. Materials and Methods: Colon-26 cells (1 × 106 cells) were implanted into the backs of eight-week-old male BALB/c mice. When the tumor volume reached approximately 100 mm3, mice were divided into untreated (n = 10) and treated groups (n = 27). The tumors in the treated group were directly injected with MNPs (Resovist?) with iron concentrations of 500 mM (A, n = 9), 400 mM (B, n = 8), and 250 mM (C, n = 10), respectively, and MHT was performed using an AMF with a frequency of 600 kHz and a peak amplitude of 3.5 kA/m. The mice in the treated group were scanned using our MPI scanner immediately before, immediately after, 7 days, and 14 days after MHT. We drew a region of interest (ROI) on the tumor in the MPI image and calculated the average, maximum, and total MPI values and the number of pixels by taking the threshold value for extracting the contour as 40% of the maximum MPI value (pixel value) within the ROI. These parameters in the untreated group were taken as zero. We also measured the relative tumor volume growth (RTVG) defined by (V-V0)/V0, where V0 and V are the tumor volumes immediately before and after MHT, respectively. Results: The average, maximum, and total MPI values decreased up to 7 days after MHT and remained almost constant thereafter in all groups, whereas the number of pixels tended to increase with time. The RTVG values in Groups A and B were significantly lower than those in the control group 3 days or more and 5 days or more after MHT, respectively. The above four parameters were significantly inversely correlated with the RTVG values 5, 7, and 14 days after MHT. Conclusion: MPI can visualize and quantify the intratumoral distribution and temporal change of MNPs before and after MHT. Our results suggest that MPI will be useful for predicting the therapeutic effect of MHT and for the treatment planning of MHT.

PREPARATION OF HOLLOW LATEX PARTICLES BY ALKALI-ACID TREATMENT

Hollow polymer latex particles were prepared by seeded emulsion polymerization. A seed latex consisting of styrene (St), butyl acrylate(BA) copolymer was first prepared, and seeded terpolymerization of St BA MA(methacrylic acid) were then carried out in the absence of surfactant. Final latex was treated by a two step treatment under alkaline and acidic conditions, thus, the particles with hollow structure were obtained. We discussed the effects of pH value, temperature and time in alkali and acid treatment processes on hollow structure within the polymer latex particles and amount of carboxylic group on particle surface. The results show that the hollow polymer latex particles with the largest hollow size can be obtained under a certain condition (pH12.5, 90°C, 3 h in alkali treatment stage and pH2.5, 85°C, 3 h in acid treatment stage).

Degradation of Diclofenac in Molecularly Imprinted Polymer Submicron Particles by UV Light Irradiation and HCl Acid Treatment

A new molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using diclofenac (DFC) as a template. Binding characteristics of the MIP particles were evaluated by equilibrium binding experiments. DFC-MIP aqueous suspension and non-imprinted polymer (NIP) suspension were exposed to monochromatic UV light (253.7 nm) from low-pressure mercury lamps. UV-visible spectrophotometry (especially absorbance at 276 nm) showed that the DFC inside MIP particles degraded completely. After DFC-MIP suspension exposure to UV light the particles were completely regenerated after washing with water at least six times. The regenerated MIP particles rebounded considerable amount of DFC (approximately 88% removal of 44 ppm DFC). The stability of DFC was examined in the presence of various concentrations of hydrochloric acid (0.025 to 125 mM). Experimental results showed that degradation of DFC was efficient, depending on the acid concentration as well as the treatment time. However, there was no re-binding of DFC by the MIP particles after HCl treatment (and DDW washing) when exposed to DFC for 24 hours.

Removal of Stabilized Silver Nanoparticles from Surface Water by Conventional Treatment Processes

Engineered nanomaterials are used in many applications, including pollution sensors, photovoltaics, medical imaging, drug delivery and environmental remediation. Due to their numerous applications, silver nanoparticles (Ag NPs) are receiving a large amount of attention. Ag NPs may occur in drinking water sources either during manufacturing, consumption and/or disposal processes. This potentially leads to the presence of Ag NPs in finished drinking water, which could have public health impacts. The objective of this research was to investigate the removal of several types of stabilized Ag NPs by potable water treatment processes. Specifically, this research achieved these objectives through: 1) Synthesis of Citrate-reduced Ag NPs, Polyvinylpyrrolidone stabilized (PVP) Ag NPs and Branched polyethyleneimine stabilized (BPEI) Ag NPs, 2) Characterization of synthesized Ag NPs to determine their aggregation potential, Zeta potential profiles, (pHpzc) and obtain morphological data from SEM images, and 3) An evaluation of the efficacy of conventional water treatment processes (i.e., coagulation, flocculation, sedimentation and sand filtration) in removing stabilized Ag NPs from natural water. The three NPs were found to be stable at the nano size in natural water. Alum coagulation had no impact on the PVP and BPEI Ag NPs. Flocculation and settling were found to be key steps for removal of these NPs. The three Ag NPs were not permanently removed by means of conventional water treatment processes employed in this study.

Effects of microwave oxygen plasma treatments on microstructure and Ge-V photoluminescent properties of diamond particles

The microstructure and Ge-V photoluminescent properties of diamond particles treated by microwave oxygen plasma are investigated.The results show that in the first 5 min of microwave plasma treatment,graphite and disordered carbon on the surface of the particles are etched away,so that diamond with regular crystal plane,smaller lattice stress,and better crystal quality is exposed,producing a Ge-V photoluminescence(PL)intensity 4 times stronger and PL peak FWHM(full width at half maximum)value of 6.6 nm smaller than the as-deposited sample.It is observed that the cycles of‘diamond is converted into graphite and disordered carbon,then the graphite and disordered carbon are etched’can occur with the treatment time further increasing.During these cycles,the particle surface alternately appears smooth and rough,corresponding to the strengthening and weakening of Ge-V PL intensity,respectively,while the PL intensity is always stronger than that of the as-deposited sample.The results suggest that not only graphite but also disordered carbon weakens the Ge-V PL intensity.Our study provides a feasible way of enhancing the Ge-V PL properties and effectively controlling the surface morphology of diamond particle.

Analyses on uniformity of particles under HPGR finished grinding system

In order to deal with the disadvantages of excessive grinding and non-uniformity in finished particle under high-pressure grinding rolls （HPGR） finished grinding system, four aspects were investigated, including evaluating indicators, effects of operating factors, effect of particle uniformity on the flotation and formation mechanism of particle uniformity. Experiment of HPGR finished grinding system, cationic reverse flotation experiment and simulation test of particle bed comminution under the condition of quasi-static were carried out. Theoretical analyses indicated that both of uniformity coefficient and average particle size should be included in the uniformity analysis of the mineral particles. The results show that the effect of circulation fan impeller speed on particle uniformity is the most evident, HPGR working pressure and roll gap are second and HPGR roller speed is the last. Average particle size has a more obvious effect on the grade of flotation concentrate while uniformity coefficient has a more obvious effect on the flotation recovery. Considering the two aspects of grade and recovery, the optimal uniformity coefficient for flotation is 1.1-1.2 and the optimal average particle size for flotation is 50-55 μm. The operating factors which promote the shielding effect and compact effect in the HPGR finished grinding system should be strengthened based on the uniformity of particles.

INFLUENCES OF ACID POST-TREATMENT ON THE MORPHOLOGY OF SOAP-FREE P(MMA-EA-MAA)PARTICLES PREPARED BY SEEDED EMULSION POLYMERIZATION

Soap-free poly（methyl methacrylate-ethyl acrylate-methacrylic acid） latex particles with narrow size distribution were synthesized by seeded emulsion polymerization, and the porous particles were created by a stepwise alkali/acid treatment method. Effects of acid treatment conditions on the particle morphology were investigated. Results show that one to three pores were formed inside most of particles after post-treatment. At pH 7.0, when the treatment temperature was lower than 70℃, the size of particles and the volume of pores remained almost unchanged, and these two values increased significantly when the temperature was higher than 70℃. Both the particle size and the pore volume decreased with the increase of initial pH value and treatment time in the acid treatment. As the pH was below 4.0 and the treatment time was longer than 180 min, the particles shrunk in size.

Influence of aging treatment on mechanical properties and wear resistance of medium manganese steel reinforced with Ti(C,N) particles

In this study,the hot rolled medium manganese steel containing titanium was solution treated at 1,000°C and followed by aging treatment at 500,550,and 600°C.The influence of aging treatment on mechanical properties and wear resistance of medium manganese steel reinforced with Ti(C,N)particles was investigated.It was found that the matrix of medium manganese steel was austenite.The austenite grain size was refined,and Ti(C,N)particles were precipitated after aging treatment.Compared to that of the as-hot rolled sample,the initial hardness of 500°C aged sample increased by 9.5%to 312.86 HV,whose impact energy was more than doubled to 148.5 J.As the aging temperature raised to 600°C,the initial hardness changed slightly.However,the impact energy dropped significantly to 8 J due to the aggregation of Mn at the grain boundaries.In addition,the main wear mechanisms of the samples were fatigue wear and abrasive wear.It was worth noting that 500°C aged sample exhibited the best wear resistance under a 300 N applied load,whose wear loss was just half of the as-hot rolled sample.The relationship between wear loss and mechanical properties indicated that the wear resistance of medium manganese steel was independent of the initial hardness.The large difference in the wear resistance was predominately due to the outstanding work hardening ability of 500°C aged sample,whose strengthening mechanisms were contributed from transformation induced plasticity(TRIP)effect,dislocation strengthening,twinning induced plasticity(TWIP)effect,and precipitation strengthening.

Effect of Heat Treatment on Microstructure and Mechanical Properties of Multiscale SiC_p Hybrid Reinforced 6061 Aluminum Matrix Composites

The performance of solid solution aging treatment on aluminum matrix composites prepared by powder metallurgy and reinforced with 6061 aluminum alloy powder as matrix;meanwhile, nano silicon carbide particles(nm Si Cp), submicron silicon carbide particles(1 μm Si Cp) and Ti particles were studied. The Al/Si Cp composite powder was prepared by high-energy ball milling, and then cold-pressed, sintered, hotextruded, and then heat-treated with different solution temperatures and aging times for the extruded composites. Optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy(EDS), X-ray diffractometer(XRD) and extrusion testing were used to analyze and test the microstructure and mechanical properties of aluminum matrix composites. The results show that after the multi-stage solid solution at 530 ℃×2 h+535 ℃×2 h+540 ℃×2 h, the particles are mainly equiaxed grains and uniformly distributed. There is no reinforcement agglomeration, and the surface is dense and the insoluble phase is basically dissolved. In the matrix, the strengthening effect is good, and the hardness and compressive strength are 179.43 HV and 680.42 MPa, respectively. Under this solution process, when the aluminum matrix composites are aged at 170 ℃ for 10 h, the hardness and compressive strength can reach their peaks and increase to 195.82 HV and 721.48 MPa, respectively.

Small particle drug-eluting beads-transarterial chemoembolization combined with targeted therapy in the clinical treatment of unresectable liver cancer

BACKGROUND Liver cancer is a highly malignant tumor with significant clinical impact.Chemotherapy alone often yields suboptimal outcomes in both the short and long term,characterized by high rates of local recurrence and distant metastasis,leading to a poor long-term prognosis.AIM To evaluate the clinical efficacy of small particle drug-eluting beads-transarterial chemoembolization(DEB-TACE)combined with targeted therapy for the treatment of unresectable liver cancer.METHODS We analyzed clinical data from 74 patients with unresectable liver cancer admitted between January 2019 and December 2020.Based on the different treatment regimens administered,patients were divided into the control(36 patients receiving sorafenib alone)and joint(38 patients receiving small particle DEB-TACE combined with sorafenib)groups.We compared liver function indicators[alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL),albumin(ALB)]and serum tumor markers[alpha fetoprotein(AFP)]before and after treatment in both groups.Short-term efficacy measures[complete response(CR),partial response,progression disease,stable disease,objective response rate(ORR),and disease control rate(DCR)]were assessed post-treatment.Long-term follow-up evaluated median overall survival(OS),progression-free survival(PFS),and adverse reaction rates between the two groups.RESULTS One month post-treatment,the joint group demonstrated significantly higher rates of CR,ORR,and DCR compared to the control group(P<0.05).Three days after treatment,the joint group showed elevated levels of ALT,AST,and TBIL but reduced levels of ALB and AFP compared to the control group(P<0.05).The median OS was 18 months for the control group and 25 months for the joint group,while the median PFS was 15 months for the control group and 22 months for the joint group,with significant differences observed(log-rank:χ2=7.824,6.861,respectively;P=0.005,0.009,respectively).The incidence of adverse reactions was not significantly different between the groups(P>0.05).CONCLUSION The combination of small particle DEB-TACE and sorafenib significantly improves both short-and long-term outcomes in the treatment of unresectable liver cancer while preserving liver function.

Effects of high pressure roller grinding on size distribution of vanadium-titanium magnetite concentrate particles and improvement of green pellet strength

The vanadium-titanium magnetite concentrate from Panxi region of China was pretreated by high pressure roller grinding（ HPRG） and then used in pelletization. Size distribution change of the vanadiumtitanium magnetite concentrate after HPRG and the improvement of its green pellet strength were investigated. The results indicated that,besides the increase of fine particles,the vanadium-titanium magnetite concentrate after HPRG had a smaller size ratio of fine particle to coarse particle of 0. 126,meaning a lower porosity,compared with the size ratio of raw material of 0. 157. The concentrate particles were more closely packed when there was a smaller size ratio of fine particle to coarse particle. The particle packing in the green pellets was closer after HPRG,which strengthened the green pellets with an average drop number of 5. 1（ drop height of 0. 5 m） and average compressive strength of 13. 1 N per pellet of 11 mm in diameter.

Influence of microwave treatment on grinding and dissociation characteristics of vanadium titano-magnetite

The effect of microwave treatment on the grinding and dissociation characteristics of vanadium titano-magnetite(VTM) ore were investigated using scanning electron microscopy(SEM), nitrogen absorption measurements, particle size distribution measurements, X-ray diffraction(XRD) analysis, Fourier transform infrared(FT-IR) spectroscopic analysis, and magnetic separation. SEM analysis showed that microfractures appeared in the microwave-treated VTM, which is attributed to the microwaves' selective heating characteristic and the differential expansion between minerals and gangues. Nitrogen absorption showed that the microfractures were more pronounced when the microwave heating time was increased. Particle size distribution analysis showed that microwave treatment could improve the grindability of the VTM, thus increasing the weight percent of the fine-ground product. The increase in grindability was more significant with prolonged heating time. Moreover, the particle size distribution of the fine-ground product changed only slightly after the microwave treatment. XRD analysis showed that the crystallinity of the microwave-treated VTM increased with increasing microwave heating time. The magnetic separation tests revealed that the separation efficiency increased as a result of the intergranular fractures generated by microwave treatment. The Fe grade of the magnetic fraction of microwave-treated VTM was 1.72% higher than that of the raw ore. We concluded that the microwave treatment was beneficial, especially for the mineral processing characteristics.

Comparison between 4D robust optimization methods for carbon-ion treatment planning

Intensity-modulated particle therapy(IMPT)with carbon ions is comparatively susceptible to various uncertainties caused by breathing motion,including range,setup,and target positioning uncertainties.To determine relative biological effectiveness-weighted dose(RWD)distributions that are resilient to these uncertainties,the reference phase-based four-dimensional(4D)robust optimization(RP-4DRO)and each phase-based 4D robust optimization(EP-4DRO)method in carbon-ion IMPT treatment planning were evaluated and compared.Based on RWD distributions,4DRO methods were compared with 4D conventional optimization using planning target volume(PTV)margins(PTV-based optimization)to assess the effectiveness of the robust optimization methods.Carbon-ion IMPT treatment planning was conducted in a cohort of five lung cancer patients.The results indicated that the EP-4DRO method provided better robustness(P=0.080)and improved plan quality(P=0.225)for the clinical target volume(CTV)in the individual respiratory phase when compared with the PTV-based optimization.Compared with the PTV-based optimization,the RP-4DRO method ensured the robustness(P=0.022)of the dose distributions in the reference breathing phase,albeit with a slight sacrifice of the target coverage(P=0.450).Both 4DRO methods successfully maintained the doses delivered to the organs at risk(OARs)below tolerable levels,which were lower than the doses in the PTV-based optimization(P<0.05).Furthermore,the RP-4DRO method exhibited significantly superior performance when compared with the EP-4DRO method in enhancing overall OAR sparing in either the individual respiratory phase or reference respiratory phase(P<0.05).In general,both 4DRO methods outperformed the PTV-based optimization in terms of OAR sparing and robustness.

淡水池塘养殖尾水处理技术研究综述

为实现水产养殖业节能减排、低碳高效和可持续发展,必须解决传统池塘养殖尾水处理问题。根据典型池塘养殖尾水污染物特性,全面总结国内外淡水池塘养殖尾水的处理方法和技术特点;对比了“三池两坝”“集装箱+生态塘”“生态湿地”等典型池塘养殖尾水处理模式;分析了竖流沉淀、旋流分离、滤筛、气浮等物理净化技术以及臭氧-微纳米浮选、絮凝、微生物制剂、活性污泥、新型生物膜反应器过滤、水生植物等化学及生物净化技术;指出了该领域的热点研究方向和关键技术问题,包括发展“节能、减排、生态、高效”集约化池塘养殖模式、研发养殖尾水专用处理装备、提高净化效率和减少占地面积等,可为池塘养殖尾水处理技术及相关装备研发提供一定的理论参考。

不同预时效挤压态Mg−Gd−Y−Zn−Zr合金的再结晶行为和强化机制

通过控制预时效时间制备3种不同状态的试样,研究不同预时效状态对挤压态Mg−9.5Gd−4Y−2.2Zn−0.5Zr(质量分数,%)合金的动态再结晶行为(DRX)和性能的影响。结果表明,欠时效挤压(UAE)样品的细晶体积分数为17.4%,而峰时效挤压(PAE)和过时效挤压(OAE)样品的细晶体积分数分别达到89.7%和50.4%。在晶粒内部和晶界处分布的致密、细小的β颗粒相通过粒子激发形核机制显著提高了形核位点和位错密度。然而,致密针状γ'相抑制位错滑移,延迟DRX形核。PEA和OAE样品中细小晶粒的差异归因于原始颗粒相的数量和尺寸的不同,而其拉伸性能的差异归因于不同的显微组织。由于晶界强化和析出强化机制的贡献更大,PAE样品具有更优异的拉伸性能。

2023年浮选药剂研究进展

本文收集了2023年国内核心期刊发表的部分浮选药剂的信息,分硫化矿捕收剂、氧化矿捕收剂、调整剂、起泡剂与助磨剂及助滤剂、浮选药剂的结构与性能和废水处理六个方面介绍并略加评论。

双轴式不定偏心法对提高磁粒研磨轨迹均匀性的研究

为解决TC4钛合金表面研磨不均匀、研磨轨迹重叠与加工效率低的问题,提出1种双轴式不定偏心磁粒研磨法。利用Adams软件模拟单颗磨粒的运动轨迹,采用统计方法计算运动轨迹密度的标准差值,作为平面运动轨迹均匀性的定量评价值。采用单轴式磁粒研磨法、双轴式定心磁粒研磨法和双轴式不定心磁粒研磨法在主轴转速350 r/min,研磨间隙1.5 mm的实验条件下对TC4钛合金平面研磨60 min,通过表面粗糙度、平面度大小和表面形貌来表征工件的表面均匀性。结果表明相同实验条件下采用双轴式不定偏心磁粒研磨法进行表面光整加工,粗糙度Ra由3.60μm下降到0.21μm,最大高度差由41.0μm变为6.3μm,平面度由0.0297 mm变为0.0072 mm,相比较于其它2种加工方式,双轴式不定偏心磁粒研磨既可以提高研磨效率,又可以使磨粒的运动轨迹密集程度大幅度减小,研磨轨迹更加均匀,有效去除了工件表面缺陷,显著提升表面均匀性。

高体积分数SiCp/Al复合材料磨削特性研究

目的为获得高体积分数铝基碳化硅(SiCp/Al)的高质量加工表面,对材料磨削去除特性和表面质量形成机制进行研究。方法在高速立式加工中心上对工件进行磨削实验,并采集加工中的磨削力,观测加工后工件的表面形貌。研究了磨削深度、进给速度和主轴转速对材料表面粗糙度、表面缺陷比例和磨削力的影响规律,结合有限元仿真分析,揭示磨削参数对增强SiC颗粒不同失效形式的影响。结果磨削深度对元件表面质量和磨削力的影响权重最大,降低磨削深度可以显著减小磨削力并降低表面粗糙度及表面缺陷比例。同时,提高主轴转速或降低进给速度能够在减小磨削力的同时降低表面粗糙度与表面缺陷比例。结论当采用10μm的磨削深度、40 mm/min的进给速度和10000 r/min的主轴转速(即磨削速度5.23 m/s)时,能够获得粗糙度Ra=0.416μm的SiCp/Al表面,与初始表面粗糙度相比,优化了72.6%。

面向造纸污水处理的故障诊断复合算法研究

故障诊断是保障系统稳定性与安全性的关键节点。在造纸污水处理过程中,系统硬件设备由于长期处于恶劣环境极易引发系统故障,因此准确诊断故障以避免不可挽回的损失至关重要。基于此,针对造纸污水处理过程的特点,以主成分分析技术提取故障主元而明确故障诊断模型输入量,以粒子群优化算法优化机器学习算法支持向量机而构成故障诊断复合算法,由此搭建了面向造纸污水处理的故障诊断模型,并进行了仿真分析。结果发现,面向造纸污水处理的故障诊断复合算法正确率可达96.9%,且稳定性与鲁棒性较高,可广泛推广至多工业污水处理领域。

陶瓷介质搅拌磨对炼焦中煤解离特性与分选潜势的影响

为研究炼焦中煤在搅拌磨机中的选择性解离特性,以涡北选煤厂的炼焦中煤为对象,进行了样品性质、磨矿条件优化、磨矿产品解离特性及颗粒形状特性等研究,对比了相同磨矿细度下搅拌磨机和棒磨机磨矿产品的浮选效果。研究结果表明:在搅拌磨机磨矿时间4min、陶瓷球直径6mm、介质填充率60%、磨矿浓度55%的最优磨矿条件下,-0.074mm含量79.39%的磨矿产品经过浮选,可得到产率61.49%的精煤(A_(d)=11.50%)产品;在相同的磨矿细度下,搅拌磨机所需的磨矿时间更短,产生的高灰细泥产率低,磨矿产品浮选精煤(A_(d)=11.50%)产率较棒磨机高9.82个百分点,说明搅拌磨机解离效果更好;SEM分析进一步证实,搅拌磨机磨矿产品表面微细粒脉石矿物较少,颗粒球形度(R0)低,伸长率(EW)高,有利于颗粒与气泡的黏附;研究结果可为炼焦中煤选择性解离提供工艺思路。