Bessel‐beam illumination in dual‐axis confocal microscopy mitigates resolution degradation caused by refractive heterogeneities

One of the main challenges for laser‐scanning microscopy of biological tissues with refractive heterogeneities is the degradation in spatial resolution that occurs as a result of beam steering and distortion. This challenge is particularly significant for dual‐axis confocal (DAC) microscopy, which achieves improved spatial‐filtering and optical‐sectioning performance over traditional confocal microscopy through off‐axis illumination and collection of light with low‐numerical aperture (NA) beams that must intersect precisely at their foci within tissues. DAC microscope image quality is sensitive to positional changes and distortions of these illumination‐ and collection‐beam foci. Previous studies have shown that Bessel beams display improved positional stability and beam quality than Gaussian beams when propagating through tissues with refractive heterogeneities, which suggests that Bessel‐beam illumination may enhance DAC microscopy of such tissues. Here, we utilize both Gaussian and Bessel illumination in a point‐scanned DAC microscope and quantify the resultant degradation in resolution when imaging within heterogeneous optical phantoms and fresh tissues. Results indicate that DAC microscopy with Bessel illumination exhibits reduced resolution degradation from microscopic tissue heterogeneities compared to DAC microscopy with conventional Gaussian illumination.

     

Changes in DNA base sequences in the mutant of Arabidopsis thaliana induced by low-energy N+ implantation

Arabidopsis thaliana (L.) Heynh has many advantages for genome analysis, including a short generation time, small size, large number of offspring, and a relatively small nuclear genome in comparison to other angiosperms and contains a low proportion of repetitive DNA comparatively. Furthermore, the analysis of the completed genome sequence of A. thaliana has been reported[1]. Low-energy ion implantation has attracted more and more attention from researchers in China and Japan since recent s…     

离子注入选育高产壮观链霉菌的研究

利用离子注入选育高产壮观链霉菌。壮观链霉菌1043为一壮观霉素生产菌种,通过实验建立了离子注入选育壮观链霉菌。其效价较出发菌株提高了102.3%。     

重离子辐射治疗进展

本文简略地回顾了重离子治疗的历史,更多的兴趣集中在重离子治癌的进展上。为了利用重离子的优越特性(例如：剂量局域性和高的生物效率),已经开发了几种技术。在临床试验中获得了令人鼓舞的治疗效果,广泛地提出了物理和辐射生物方面的临床结果和治疗技术,概要地分析了重离子治癌的前景。     

高斯光束通过生物体混浊介质模型的测量

将各向同性的沸浊介质材料作为生物组织的光学模型,用2mw单模He-Ne高斯激光透过该混浊介质材料,测量透射率、偏振度及透射光强的分布,得到了偏振度（ν）与透射率（T）的关系曲线。当透射率T＜30％时,偏振度ν→0,高斯激光束透过混浊介质材料,受散射影响,光强偏离高斯分布,并提出了透射光强分布公式。     

Adjuvant radiotherapy in malignant tumors of parotid. Experience of the Navarra Hospital Complex

BackgroundThe objective of the study was to review the outcome of patients with parotid cancer treated with postoperative radiotherapy at Complejo Hospitalario de Navarra in the last ten years.Materials and methodsWe retrospectively reviewed patients treated with adjuvant radiotherapy between January 2008 and December 2018. We analyzed demographic data, histopathologic findings, local control (LC) and overall survival (OS).ResultsA total of 40 patients received postoperative radiotherapy during the period mentioned. There were 22 men (55%) and 18 women (45%). Median age was 58 years (19–90). By tumor histology, the most common was squamous cell carcinoma (22.5%) followed by ex-pleomorphic adenoma (15%) and adenoid cystic carcinoma (10%). According to Surgery, 19 patients (47.5%) underwent a total parotidectomy, 20 (50%) partial parotidectomy, and 1 (2.5%) a radical parotidectomy. Twenty-one patients (51.2%) underwent cervical dissection, most of them being supraomohyoid (31.7%). Reasons for adjuvant RT were: R1 resection (35% of the patients), high grade tumors (27.5%) and 17.5% because R1 surgery and R1. Radiation was administered using IMRT in most patients to a total dose of 60 Gy in 30 fractions. The 5-year overall survival (OS) (Kaplan-Meier) was 81% (95% CI: 68.5–96.2%), and 10-years — 64%. The 5-year local control (LC) (Kaplan-Meier) was 82.4% (95% CI: 91.46–73.33%) and the 10-year LC — 72.2% (95% CI: 54.9–96%). To date, only 4 patients (10%) have died due to their parotid tumor.ConclusionThe adjuvant radiotherapy added to surgery, significantly reduces the risk of recurrence in high-risk patients with a very acceptable survival rate.     

超低能离子束注入后番茄的生物学效应

利用超低能氮离子束注入河南四号番茄干种子,观察发芽率及田间农艺性状的表现,采用聚丙稀酰胺凝胶电泳的方法分析M0代、M1代幼苗期过氧化物酶和酯酶同工酶的变化。结果表明,不同剂量间芽率的变化幅度较小,其总趋势是先升高后略微下降,呈现“马鞍型”曲线。但在幼苗期群体内某些单株的子叶呈镰刀型,其刺激效应十分明显,并且在7×1017N /cm2剂量下M1材料中发现5株突出的变异单株,呈细叶型、长花瓣,株型、果形已发生明显得变异,并且已经稳定遗传到第四代。同工酶分析显示:超低能离子束注入河南四号番茄后不同剂量间POD酶活性有差异,比对照酶活性增强,M1代突变体的POD酶活增强更显著;EST同工酶的活性表现不同,M1-1酶谱的带数比对照少四条,M1-2比对照多出四条,且主酶带比对照颜色深。由此认为,超低能离子注入技术对番茄的遗传改良有一定效果。     

离子束介导GUS基因转化拟南芥种子的研究

以拟南芥种子为研究对象,研究离子束介导GUS基因导入拟南芥种子的转化效果。结果表明:直接注入干种子后进行转化,未得到瞬间表达的结果。而注入玻璃化保护后的2天龄幼苗,再进行转化,转化效果明显提高,得到了大约10%的瞬间表达。揭示对于像拟南芥这样的小粒种子,采用幼苗注入后转化,效果可能会更好一些。     

Tris对高LET碳重离子辐照下质粒DNA链断裂的保护作用

利用100 keV/μm碳离子束(初始能量为290 MeV/u)照射溶解于纯水、10 mmol/L Tris、1 mmol/L EDTA及TE 缓冲液中的pUC19质粒DNA.通过琼脂糖凝胶电泳技术分析了不同溶液中各种形态DNA分子所占份额,并计算得到不同剂量下平均每个质粒分子中单链断裂(SSB)及双链断裂(DSB)的数目.发现Tris通过抑制SSB和DSB的产生对碳重离子辐照下的质粒DNA有明显的保护作用,而EDTA能够加剧SSB的产生而抑制DSB的形成.     

离子束诱变育种研究及应用进展

阐述了离子束诱变的生物效应,研究中有待解决的问题,介绍了离子束诱变在农业、工业育种上的研究进展及成果,并展望了今后的研究前景。