Carbon-Ion Beams Efficiently Induce Cell Killing in X-Ray Resistant Human Squamous Tongue Cancer Cells

In order to see whether carbon ion (C-ion) beams have a biological advantage over X-rays, studies were designed to examine the effects of C-ion beams on radiosensitivity in X-ray resistant cells. Clinically relevant X-ray resistant SAS-R cells derived from human tongue cancer SAS cells were used. The cells were exposed to X-rays or Spread-Out Bragg peak (SOBP) beam C-ions. Cell survival was measured using a modified high-density survival assay. Cell survival signaling and cell death signaling were analyzed using flow cytometry. The cells were labeled with putative cancer stem cell markers such as CD44 and CD326. SAS-R cells were 1.6 times more radioresistant than SAS cells after exposure to X-rays. Cell survival was similar in each cell line after exposure to C-ion beams. SAS-R cells displayed enhanced cell survival signaling when compared to SAS cells under normal conditions. On the other hand, the phosphorylation of AKT-related proteins decreased and polycaspase activities were enhanced when cells were irradiated with C-ion beams in both cell lines. More CD44 and CD326 positive cells were seen in SAS-R cells than in SAS cells. Moreover, the marker positive cell numbers significantly decreased after exposure to C-ion beams when compared to X-rays at iso-survival doses in SAS-R cells. C-ion beams efficiently induced cell killing in X-ray resistant cells which displayed activated cell survival signaling and contained more numerous cancer stem-like cells.

Protective Effects of Shikonin on Brain Injury Induced by Carbon Ion Beam Irradiation in Mice

Radiation encephalopathy is the main complication of cranial radiotherapy. It can cause necrosis of brain tissue and cognitive dysfunction. Our previous work had proved that a natural antioxidant shikonin possessed protective effect on cerebral ischemic injury. Here we investigated the effects of shikonin on carbon ion beam induced radiation brain injury in mice. Pretreatment with shikonin significantly increased the SOD and CAT activities and the ratio of GSH/GSSG in mouse brain tissues compared with irradiated group （P〈0.01）, while obviously reduced the MDA and PCO contents and the RO$ levels derived from of the brain mitochondria.

Flower color mutants induced by carbon ion beam irradiation of geranium (Pelargonium × hortorum, Bailey)

In an attempt to elucidate the biological effects and underlying mutations involving flower color in ornamental plants following carbon ion beam radiation,shoots of geranium were exposed at dosages of 0,10,15,30,and40 Gy,and one flower color mutant was obtained.The morphological characteristics,physiological aspects,and DNA polymorphisms between wild-type and flower color mutants were analyzed.The colors of petal,peduncle,pistil,and stamen of the mutant displayed significant differences compared to those of the wild-type.Compared to the original plants,the total anthocyanin content in the petals of the mutant significantly decreased,resulting in a light pink petal phenotype.DNA polymorphisms detected by random amplified polymorphic DNA analysis showed that the ratio of different bands between the wild-type and mutant reached up to 13.2%.The present study demonstrates that carbon ion beam irradiation is effective in inducing genomic variations,resulting in flower color geranium mutants within a relatively short period of time.Meanwhile,the developed flower-color mutants may be potentially used in future mutational research studies involving ornamental plants.

Gate/Geant4-based Monte Carlo simulation for calculation of dose distribution of 400 MeV/u carbon ion beam and fragments in water

The applications of carbon ion beam in tumor therapy have attracted more attention in recent years.Monte Carlo simulation is an important approach to obtain accurate radiotherapy parameters. In this work, a400 Me V/u carbon ion beam incident on water phantom was simulated with Gate/Geant4 tools. In methods, the authors set up a carbon ion beam source according to the experiment parameters of Haettner, defined the geometries and materials, set up the physics processes, and designed the means of information collection. In results,the authors obtained the longitudinal dose distribution, the lateral dose distribution, and the relative uncertainty of dose. The dose contributions of all kinds of fragments were calculated detailedly and compared with the Francis results. This work is helpful for people's understanding of the dose distributions produced by carbon ion beam and fragments in water. The simulation method is also significative for radiotherapy treatment planning of carbon ion beam, and it is easy to extend. For obtaining a special result, we may change the particle energy, particle type,target material, target geometry, physics process, detector,etc.

Intensive irradiation of carbon nanotubes by Si ion beam

Multi-walled carbon nanotubes were irradiated with 40 keV Si ion beam to a dose of 1×1017 cm-2. The multiple-way carbon nanowire junctions and the Si doping in carbon nanowires were realized. Moreover, the forma- tion processes of carbon nanowire junctions and the corresponding mechanism were studied.

Deposition of diamond like carbon films by using a single ion gun with varying beam source

Diamond like carbon films have been successfully deposited on the steel substrate, by using a single ion gun with varying beam source. The films may appear blue, yellow and transparent in color, which was found related to contaminants from the sample holder and could be avoided. The thickness of the films ranges from tens up to 200 nanometers, and the hardness is in the range 20 to 30 GPa. Raman analytical results reveal the films are in amorphous structure. The effects of different beam source on the films structure are further discussed.

Pigment analysis of a color-leaf mutant in Wandering Jew (Tradescantia fluminensis) irradiated by carbon ions

Many mutants of plant induced by heavy ion beam irradiation have been reported in recent years,but leaf anthocyan mutants induced by ion irradiation in evergreen were rarely found.In this study,a color-leaf mutant with purple leaves,stems and petals was isolated from clones of Wandering Jew irradiated by 95.8 MeV/u carbon ion beam.The concentration and histological distribution of leaf pigment were surveyed in wild type and mutant.In mutant,contents of total chlorophylls (Chl),chlorophyll a (Chl a),chlorophyll b (Chl b) and carotenoids (Car) decreased significantly,while concentration of the anthocyanins was 6.2-fold higher than that of wild type.Further composition analysis of anthocyanins by electrospray ionization mass spectrometry (ESI-MS) indicated that the purple pigmentation of leaves in mutant was caused by accumulation of petunidin anthocyanin.Microscopic examination showed that most petunidin anthocyanin accumulated in the lower epidermis,and little in vascular parenchyma of mutant,while there was no pigment in wild type.Meanwhile,in spongy parenchyma of mutant we observed little Chl,which the wild type abounds in.In conclusion,the color-leaf mutant of Wandering Jew induced by irradiation of carbon ions was improved in ornamental value,and it could be contribute to variation in level,component and distribution of foliar pigment.The possible mutation mechanisms were discussed.

Enhanced field emission from nano-graphite coated carbon nanotubes

An effective method by low energy carbonhydrogen ion treatment to enhance field emission of the carbon nanotubes (CNTs) is demonstrated. Comparing with control, field emission (FE) currents of the CNTs by carbonhydrogen ion irradiation increased, and the turn-on field and the threshold field decreased significantly. The structure characteristic revealed by transmission electron microscopy demonstrates that CNTs are coated by nano-graphite particles after being treated with low energy carbonhydrogen ion and that there are large quantities of defects and grain boundaries in the coated layer. It is considered that the coating layer can decrease the effective surface work function of CNTs and correspondingly increase field emission. In addition, the defects, the grain boundaries and the C-H dipoles forming in the process of the low energy ions irradiation can effectively enhance the field emission.

Effect of bombarding energy on ion beam assisted deposited DLC film on UHMWPE

Diamond-like carbon (DLC) films on ultra-high molecular weight polyethylene substrates were prepared at CHn+ ion bombarding energies of 200-1000eV at room temperature using ion beam assisted deposition technique. The wear tests exhibited a high wear resistance for all DLC films. X-ray photoelectron spectfoscopy and Raman spectroscopy analysis indicated that DLC film was amorphous with a characteristic high fracdion of sp3 bonds in the structure of mixed sp:2+ sp3 bonding at an optimal bombardingenergy of 600eV.

Hypofractionated particle beam therapy for hepatocellular carcinoma–a brief review of clinical effectiveness

Hepatocellular carcinoma(HCC)is the fifth most common malignancy and the second leading cause of cancer mortality worldwide.The cornerstone to improving the prognosis of HCC patients has been the control of loco-regional disease progression and the lesser toxicities of local treatment.Although radiotherapy has not been considered a preferred treatment modality for HCC,charged particle therapy(CPT),including proton beam therapy(PBT)and carbon ion radiotherapy(CIRT),possesses advantages(for example,it allows ablative radiation doses to be applied to tumors but simultaneously spares the normal liver parenchyma from radiation)and has emerged as an alternative treatment option for HCC.With the technological advancements in CPT,various radiation dosages of CPT have been used for HCC treatment via CPT.However,the efficacy and safety of the evolving dosages remain uncertain.To assess the association between locoregional control of HCC and the dose and regimen of CPT,we provide a brief overview of selected literature on dose regimens from conventional to hypofractionated short-course CPT in the treatment of HCC and the subsequent determinants of clinical outcomes.Overall,CPT provides a better local control rate compared with photon beam therapy,ranging from 80%to 96%,and a 3-year overall survival ranging from 50%to 75%,and it results in rare grade 3 toxicities of the late gastrointestinal tract(including radiation-induced liver disease).Regarding CPT for the treatment of locoregional HCC,conventional CPT is preferred to treat central tumors of HCC to avoid late toxicities of the biliary tract.In contrast,the hypo-fractionation regimen of CPT is suggested for treatment of larger-sized tumors of HCC to overcome potential radio-resistance.

Ring chromosome aberrations in human lymphocytes induced by 5-20 Gy carbon ion irradiation

In this paper,we study the biological response induced by heavy ions irradiation of high dose,human peripheral blood lymphocytes are irradiated in vitro by the carbon ions of LET=35 keV/μm,and the chromosome aberrations at absorbed doses of 0-20 Gy are analyzed by the calyculin A-induced premature chromosome condensation(PCC).The frequencies of PCC-rings at the stage of G2/M-phase increase steeply with radiation doses up to 20 Gy at a rate of 0.017 Gy^(-1).The G2-PCC index remains more than 5%up to 15 Gy,and 3%after 20 Gy,this is high enough to score a substantial number of chromosome spreads without dose-rate effect.The results show that the calyculin A-induced PCC technique is suitable for analyzing the chromosome damage induced by carbon ions irradiation of high dose.

基于纳剂量学量模型的碳离子束相对生物学效应计算

目前癌症严重影响人类的健康,迫切需要一种能有效治疗癌症的手段.碳离子束由于其具有较高的生物学效应和独特的布拉格峰,被认为是极具有潜在价值的放疗射线.主要利用基于纳剂量学量的LNDM(Logistic NanoDosimetry Model)模型计算不同入射能量碳离子束在水模体的相对生物学效应(Relative Biologica Effectiveness,RBE).使用GATE模拟工具得到碳离子束及其碎片在水模体中不同深度的能谱和剂量,利用预先计算的带电离子纳剂量学量数据库计算得到碳离子束的四个纳剂量学量M1、■,基于LNDM模型计算碳离子束的RBE.结果表明,碳离子束的RBE峰值随着入射能量的增加而逐渐降低,并且RBE峰值出现在布拉格峰下降沿附近.

碳离子束辐照对马铃薯组培苗生长及生理特性的影响

为研究高能碳离子束对马铃薯组培苗茎切段的影响,以马铃薯品种‘新大坪’的组培苗茎切段为研究材料,设置4个辐照剂量梯度对其进行辐照处理,测定植株致死率、生根率、侧芽形成率、形态变异率以及叶片生理指标,确定‘新大坪’组培苗茎切段的半致死辐照剂量。结果表明:辐照剂量与致死率之间的关系呈正相关性;组培苗茎切段的再生植株表型变化主要为叶片不对称、叶缘不规则、茎变异伸长、叶片丛生和叶片粘连等;随辐照剂量升高,超氧化物歧化酶、过氧化物酶和过氧化氢酶活性呈先升后降的趋势;丙二醛含量则呈先升后降,随后又升高的现象。利用线性回归方程计算‘新大坪’的半致死辐照剂量为20.37 Gy。

碳离子束辐射诱变水稻基因突变嵌合体的分子特征

嵌合体是辐射诱变M1代普遍存在的现象,然而,有关水稻的嵌合体突变效应及变异遗传机制尚不清楚。本研究采用靶向捕获测序技术获得碳离子束辐照后的OsNramp5突变嵌合体,并利用10kb液相芯片检测该嵌合体的M1代及突变M2代基因组的SNP/InDel发生及变异遗传分离特征。结果表明:水稻M1代嵌合体中检测到的OsNramp5基因突变位点未遗传至M2代,即在M1代体细胞检测到的突变位点未进入生殖细胞遗传;另外,在M1基因组突变类型中,转换是颠换的2倍,虽然超过一半变异位点遗传至M2代,但很少位点来自基因功能编码区。本研究揭示了碳离子束辐照诱变的体细胞M1代嵌合体的基因组变异特征及其在M2代的遗传特征,为研究碳离子束辐照后的嵌合体突变效应机制和选择诱变育种程序提供参考。

Imaging the interphase of carbon fiber composites using transmission electron microscopy:Preparations by focused ion beam, ion beam etching, and ultramicrotomy

Three sample preparation techniques, focused ion beam （FIB）, ion beam （IB） etching, and ultramicrotomy （UM） were used in comparison to analyze the interphase of carbon fiber ＇epoxy composites using transmission electron microscopy. An intact interphase with a relatively uniform thickness was obtained by FIB. and detailed chemical analysis of the interphase was investigated by electron energy loss spectroscopy. It shows that the interphase region is 200 mn wide with an increasing oxygen-to-carbon ratio from 10% to 19% and an almost constant nitrogen-to-carbon ratio of about 3%. However, gallium implantation of FIB tends to hinder fine structure analysis of the interphase. For IB etching, the interphase region is observed with transition morphology frona amorphous resin to nano-crystalline carbon fiber, but the uneven sample thickness brings difficulty for quantitative chemical analysis. Moreover, UM tends to cause damage and/or deformation on the interphase. These results are meaningful for in-depth understanding on the interphase characteristic of carbon fiber composites.

碳离子治疗肿瘤的临床进展研究

碳离子束拥有独特的物理学及生物学优势,在肿瘤治疗过程中具有高效性和低毒性,并且整体治疗周期短,因此被认为是21世纪最理想的肿瘤放射治疗射线。但是碳离子中心建设及设备运营费用昂贵,目前世界范围内,仅有日本、德国、中国、意大利、奥地利等极少数国家将碳离子应用于临床。自1994年以来,日本一直应用碳离子束治疗恶性肿瘤,治疗效果较好。截至2022年底,全球范围内超过46800例患者接受了碳离子治疗,其中包括头颈部恶性肿瘤、肺癌、肝癌、胰腺癌等。本文总结近20年来碳离子在临床应用中的经验、治疗效果、最新发展及其作为一种新兴癌症治疗方式的优点,并将碳离子治疗与传统的光子放疗疗效及不良反应进行比较,可以帮助临床进一步了解碳离子治疗的优势及进展,并且指导关于新的碳离子治疗中心的建设,从而更好地服务于肿瘤患者。

Structure and properties of carbon nitrogen films synthesized by ion beam-assisted deposition

β-C3N4 compound is a new hard material predicted by Liu and Cohen with theoretical calculation and so far it has not been found out in nature. In was assumed that the β-C3N4 compound would adopt the known crystal structure of β-Si3N4, which constructed a network of CN4 tetrahedra linked at the corners by threefold coordinate N atoms. Thus, the atomic coordination of β-C3N4 is sp3 hybrids on the C atoms and sp2 hybrids on the N atoms. Based on the theoretical analysis and modeling calculation, it

强流脉冲碳离子束强化T5K10刀具机理研究

采用TIA-450自绝缘二极管碳离子加速器对T5K10刀具进行了强流脉冲离子束辐照表面处理,加速器的加速电压为250keV,束流密度为60A/cm2～150A/cm2,脉冲时间为80纳秒,脉冲次数为2次.XRD、SEM、EDS以及显微硬度分析研究结果表明:当束流密度达到100A/cm2,材料表面为完全熔化凝固组织;当束流密度达到150A/cm2时,表面层下也出现熔化凝固组织;熔化凝固组织没有明显相变.在100A/cm2～150A/cm2内,同未辐照表面相比,显微硬度提高1.25倍.硬度增加的主要原因是表面快速凝固组织产生硬化相和基体相中化学成分的重新分布、碳元素的烧损以及晶界的强化.

碳离子束辐照对甜高粱主要性状的影响

利用兰州重离子加速器国家实验室(HIANLL)提供的100MeV/u碳离子束对甜高粱品种BJ0601和BJ0602进行了不同剂量的辐照处理,并用SPSS13.0软件分析了碳离子束辐照剂量和甜高粱主要性状节间数、株高、茎粗、含糖量及单秆重的相关性,试验结果表明:不同的辐照剂量对甜高粱节间数、株高、茎粗、含糖量及单秆重产生了明显的影响,表现出不同程度的相关性。另外,早熟突变株BJ0601-1M2代各节的平均含糖量高于BJ0601,说明碳离子束辐照可能引起甜高粱含糖量的提高。