紫外线辐射对蓝藻细胞活性的影响

紫外线辐射 2种蓝藻Anabaena 6 3l和Anabaenaazollae不同时间 ,用UV30 0 0分光光度计测定活体连续吸收光谱 ,并测定细胞存活率。结果发现紫外线辐射对这 2种蓝藻的光合色素有不同程度的破坏作用 ;紫外线辐射 2min左右就可以杀死全部的A .6 3l和A .azollae细胞。实验还证实了小剂量刺激效应的存在。     

热带季节雨林林窗辐射特征研究

利用不同季节热带季节雨林林窗、林内及旷地不同波长太阳辐射的实测资料,探讨了热带季节雨林林窗不同波长辐射特征。结果表明,热带季节雨林林窗中央和北侧林冠下的不同波长太阳辐射存在“突跃现象”,中午前后各辐射量值迅速达到最大后又急速下降;林窗内不同波长太阳辐射日总量值均大于林内,却小于旷地;林窗中央和北侧林冠下比较可见,在干热季、雨季和雨季后期,林窗中央的各辐射要素总量值高于北侧林冠下,但雾凉季时受浓雾和太阳高度以及方位的影响,各辐射要素总量值较北侧林冠下低;林窗中央的总辐射日总量在雨季太阳高度角最大时最高,雨季后期和干热季其次,雾凉季时最小;林窗中央和北侧林冠下的红外辐射及可见光在总辐射中所占份额随季节的变化而不同,充分显示了林窗辐射环境的异质性;与旷地和林内相比,林窗内各测点的红外辐射在总辐射中所占份额介于旷地和林内之间．高于旷地却低于林内;而可见光占总辐射的比值情况正好相反．另外,林窗可见光分配率的季节变化都大于红外辐射;热带季节雨林林窗育增加红外辐射、减少可见光的特征．     

X-Ray Diffraction of Iron Containing Samples: The Importance of a Suitable Configuration

In X-ray diffraction, a good combination of configuration and sample is essential. Copper radiation for iron containing materials leads to a high background. Although this has been recognized, many researchers still use this combination. To clearly show the unsuitability of copper radiation for iron oxides, magnetite, goethite, maghemite, and hematite were analysed in different configurations using copper or cobalt radiation. Results show effects of fluorescence repressing measures and different radiation sources. Copper radiation diffractograms make phase identification contestable. Studies using copper radiation for iron oxides must therefore be carefully evaluated. Cobalt radiation yielded high quality diffractograms, making phase identification unambiguous.     

2012年春季千烟洲地区散射辐射的对比观测

利用CMP11(含遮光环)、SPN1和RSR3 3种辐射测定仪器,于2012年3-6月在中国科学院千烟洲红壤丘陵试验站开展总辐射和散射辐射的平行对比观测.结果表明: 不同辐射仪测定的总辐射和散射辐射都有很好的线性相关关系;相对于CMP11而言,SPN1和RSR3测定的总辐射分别低3.0%和20.5%;对于测定的散射辐射,SPN1和RSR3较CMP11的观测结果分别低5.5%和7.9%;在晴朗、多云、阴天3种天气条件下,各仪器测量的散射辐射日变化一致,并且在不同太阳高度角下观测的散射辐射结果相似.不同仪器测量的日尺度散射辐射随时间的累积存在一定差异,3、4、5月的月尺度散射分数分别为0.56、0.59和0.70.在我国南方中亚热带地区,散射辐射在太阳总辐射中占据了较大比例,并且随时间变化存在明显的变化特征.有必要对其开展长期连续测定,以准确把握其长期的动态变化特征.     

NMR spectroscopy based metabolic profiling of urine and serum for investigation of physiological perturbations during radiation sickness

Radiation accidents are rare events that induce radiation syndrome, a complex pathology which is difficult to treat. In medical management of radiation victims, life threatening damage to different physiological systems should be taken into consideration. The present study was proposed to identify metabolic and physiological perturbations in biofluids of mice during different phases of radiation sickness using ¹H nuclear magnetic resonance (¹H NMR) spectroscopy and pattern recognition (PR) technique. The ¹H NMR spectra of the biofluids collected from mice irradiated with 5 Gray (Gy) at different time points during radiation sickness were analysed visually and by principal components analysis. Urine and serum spectral profile clearly showed altered metabolic profiles during different phases of radiation sickness. Increased concentration of urine metabolites viz. citrate, α ketoglutarate, succinate, hippurate, and trimethylamine during prodromal and clinical manifestation phase of radiation sickness shows altered gut microflora and energy metabolism. On the other hand, serum nuclear magnetic resonance (NMR) spectra reflected changes associated with lipid, energy and membrane metabolism during radiation sickness. The metabonomic time trajectory based on PR analysis of ¹H NMR spectra of urine illustrates clear separation of irradiated mice group at different time points from pre dose. The difference in NMR spectral profiles depicts the pathophysiological changes and metabolic disturbances observed during different phases of radiation sickness, that in turn, demonstrate involvement of multiple organ dysfunction. This could further be useful in development of multiparametric approach for better evaluation of radiation damage as well as for medical management during radiation sickness.     

Impact of UV radiation on bacterioplankton community composition

The potential effect of UV radiation on the composition of coastal marine bacterioplankton communities was investigated. Dilution cultures with seawater collected from the surface mixed layer of the coastal North Sea were exposed to different ranges of natural or artificial solar radiation for up to two diurnal cycles. The composition of the bacterioplankton community prior to exposure was compared to that after exposure to the different radiation regimes using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA and 16S ribosomal DNA. Only minor changes in the composition of the bacterial community in the different radiation regimes were detectable. Sequencing of selected bands obtained by DGGE revealed that some species of the Flexibacter-Cytophaga-Bacteroides (FCB) group were sensitive to UV radiation while other species of the FCB group were resistant. Overall, only up to approximately 10% of the operational taxonomic units present in the dilution cultures appeared to be affected by UV radiation. Thus, we conclude that UV radiation has little effect on the composition of coastal marine bacterioplankton communities in the North Sea.     

自然条件下滤减UV-B辐射对烤烟光合色素含量的影响

在自然环境中,以烟草栽培品种K326为材料,通过覆盖不同透明薄膜滤减UV—B辐射,研究100％（CK）、75％（T1）、50％（T2）、35％（T3）UV—B辐射透过率处理下,不同强度UV—B辐射对烟草光合色素含量的影响。结果表明：烤烟三类光合色素对UV—B辐射有不同响应。类胡萝卜素对UV—B辐射响应较敏感。成熟初期,类胡萝卜素含量与UV—B辐射强度变化具有较好的正相关性,而chl a和chl b含量基本与UV—B辐射强度呈反向变化关系。成熟后期,由于UV—B辐射累积效应,光合色素含量变化没有明显规律。现蕾期至成熟采烤烟初期,chl a：chl b与UV—B辐射的反向变化关系较明显,后期则无明显规律,其含量的下降与UV—B辐射的累积效应有关。     

Effect of incident radiation integral on cauliflower growth and development after curd initiation

Two field experiments were conducted to assess the response of cauliflower cv. “Nautilus F1” to different radiation integrals after curd initiation by covering the plants with different levels (0, 38, 50 and 68%) of neutral shading materials during the autumn 1998 and summer 2000. Cauliflower growth and development declined with increasing shade levels after curd initiation. Total above ground dry matter increased linearly with accumulated incident radiation integral after curd initiation, however, under lower radiation conditions, the rate of increase per unit incident radiation integral was greater than under higher radiation conditions. Moreover, radiation conversion coefficient declined linearly with increasing incident radiation integrals up to approximately 6.1 MJ m⁻² d⁻¹ and thereafter, declined more slowly with further increase in incident radiation integrals. Therefore, dry matter accumulation was potentially more efficient under lower incident radiation than higher incident radiation levels. Radiation conversion coefficients for plants under low incident radiation levels were greater than under high incident radiation levels. Curd growth also increased linearly with increasing accumulated incident radiation integral with greater mean relative curd dry matter increase per MJ under lower incident radiation conditions than higher incident radiation levels.     

Impact of UV Radiation on Bacterioplankton Community Composition

The potential effect of UV radiation on the composition of coastal marine bacterioplankton communities was investigated. Dilution cultures with seawater collected from the surface mixed layer of the coastal North Sea were exposed to different ranges of natural or artificial solar radiation for up to two diurnal cycles. The composition of the bacterioplankton community prior to exposure was compared to that after exposure to the different radiation regimes using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA and 16S ribosomal DNA. Only minor changes in the composition of the bacterial community in the different radiation regimes were detectable. Sequencing of selected bands obtained by DGGE revealed that some species of the Flexibacter-Cytophaga-Bacteroides (FCB) group were sensitive to UV radiation while other species of the FCB group were resistant. Overall, only up to ≈10% of the operational taxonomic units present in the dilution cultures appeared to be affected by UV radiation. Thus, we conclude that UV radiation has little effect on the composition of coastal marine bacterioplankton communities in the North Sea.     

Modelling the effects of changes in solar radiation on gross primary production in subtropical evergreen needle-leaf plantations

太阳辐射是陆地生态系统碳水循环的能量来源。太阳辐射的变化对植被吸收大气CO₂具有重要影响。该文通过辐射观测数据建立散射辐射比例与晴空指数的关系, 结合生态过程模型(BEPS)和通量观测数据, 模拟分析了太阳辐射变化对千烟洲常绿针叶林总初级生产力(GPP)的影响。研究结果表明: 千烟洲森林生态系统的阴叶对年GPP总量的贡献达67%, 太阳辐射变化对阴叶光合作用的影响决定了冠层GPP的变化; 太阳辐射强度和分布的年际差异导致年GPP对太阳辐射变化的响应不同, 2003、2004和2005年太阳辐射分别变化-5.44%、-1.83%和6.26%, 可使千烟洲生态系统当年GPP总量达到最大值; 在季节上, 太阳辐射的增加会导致5-6月GPP上升, 7-9月GPP下降, 使年GPP变化程度降低; 在天尺度上, 晴空指数在0.43时, 太阳辐射变化对GPP的影响最小。     

太阳辐射变化对亚热带人工常绿针叶林总初级生产力影响的模拟分析

太阳辐射是陆地生态系统碳水循环的能量来源。太阳辐射的变化对植被吸收大气CO₂具有重要影响。该文通过辐射观测数据建立散射辐射比例与晴空指数的关系, 结合生态过程模型(BEPS)和通量观测数据, 模拟分析了太阳辐射变化对千烟洲常绿针叶林总初级生产力(GPP)的影响。研究结果表明: 千烟洲森林生态系统的阴叶对年GPP总量的贡献达67%, 太阳辐射变化对阴叶光合作用的影响决定了冠层GPP的变化; 太阳辐射强度和分布的年际差异导致年GPP对太阳辐射变化的响应不同, 2003、2004和2005年太阳辐射分别变化-5.44%、-1.83%和6.26%, 可使千烟洲生态系统当年GPP总量达到最大值; 在季节上, 太阳辐射的增加会导致5-6月GPP上升, 7-9月GPP下降, 使年GPP变化程度降低; 在天尺度上, 晴空指数在0.43时, 太阳辐射变化对GPP的影响最小。     

Suppression of delayed hypersensitivity to microbial and transplantation antigens with ultraviolet radiation

The influence of ultraviolet (UV) radiation on delayed hypersensitivity to antigens of different nature has been studied. UV radiation in different doses has been shown to induce the suppression of delayed hypersensitivity to staphylococcal cell-wall antigens and transplantation alloantigens.     

Differential radiation effect in tumor and normal tissue after treatment with ramipril, an angiotensin-converting enzyme inhibitor

The angiotensin-converting enzyme inhibitor, ramipril, has been shown to mitigate radiation injury in normal tissues. Using A549 cell xenografts grown in athymic mice, we measured the effect of ramipril on radiation damage to tumors. Ramipril did not alter tumor response to radiation despite different times of drug administration with respect to radiation delivery (drug started 2 weeks before or immediately after irradiation). In contrast, using the same dose, ramipril reduced normal tissue radiation injury (30 Gy x 2 or 6 Gy x 10) as assessed by a semi-quantitative scale of skin damage and relative leg contraction. The results indicate that ramipril could offer therapeutic gain due to its different effect on normal tissues and tumors.     

不同剂量UV-B辐射对冬小麦幼苗形态及生理指标的影响

UV-B辐射增强对植物的影响效果存在差异,即使是同一物种的不同品种之间也存在差异。本研究以对UV-B不同耐性的2个冬小麦品种科遗26和泰山269为材料,比较了品种间及UV-B的剂量间的形态指标、生物量及生理指标的差异。结果表明:高剂量UV-B处理抑制了株高、叶色、茎数、鲜质量、光反应系统Ⅱ(PSⅡ)最大光化学效率(Fv/Fm)和光合速率,促进了丙二醛、类黄酮含量的增加及相对电导率的提高,2个品种的趋势基本相同,但泰山269的变化幅度大于科遗26,说明泰山269比科遗26敏感;低剂量的UV-B对株高、叶色、茎数、鲜质量表现出促进的趋势,对类黄酮的促进作用较大,对Fv/Fm、丙二醛及相对电导率的影响相对较小。     

利用微波固定组织的收缩率

目的探讨利用微波辐射固定、微波辐射与固定液结合固定组织的收缩程度。方法将组织分成40组,用一定强度的微波辐射或一定强度的微波辐射与不同固定液结合方法固定动物组织,并制做石蜡组织切片和HE染色,在此过程中测定各步骤前后的组织块体积,计算出收缩率。结果与结论一定强度的微波辐射和一些微波辐射与固定液结合方法固定的组织收缩率低,这些组织的切片具有细胞质均匀,染色鲜艳,细胞核大而清晰的良好效果。     

Inactivation of bacteriophage lambda by combined X-ray and U.V.-light exposure.

Extracellular phage lambda has been successively exposed to X-rays and U.V. light. The plaque-forming ability of the irradiated phages was determined on host cells with different repair capacities. No change in sensitivity was found with a pre-treatment of one type of radiation to lethal damage inflicted by the other. This indicates that a prerequisite for an interaction of different types of radiation is either an active metabolism or repair process occurring during the two radiation exposures.     

低纬高原地区UV-B辐射对报春花丙二醛、蛋白质含量的影响

以同期种植的云南报春花为试验材料,利用获得的云南不同纬度、不同海拔高度,而经度差异不大的4个试验点的UV-B辐射观测资料,初步研究了低纬高原地区不同UV-B辐射强度变化对云南报春花丙二醛、可溶性蛋白质的影响。结果表明,UV-B辐射强度从2~5月呈上升趋势,辐射值最高为丽江点,5月份达12·90w·m-2,相对来说高海拔地区的紫外辐射强度较强,各试验点报春花叶片的丙二醛含量以3、4月份较高,可溶性蛋白质含量以2、4月份较高。随着UV-B辐射强度增强,报春花丙二醛含量先升高后降低,叶片丙二醛含量也较高,不同生育期丙二醛含量不同,其含量以开花期和结实期最高;而随着UV-B辐射强度的变化,各实验点报春花叶片蛋白质含量变化不一致,不同生育期可溶性蛋白质含量不同,其含量以开花期为最高。     

中天山地区草地地表辐射收支演变规律

地表辐射对研究地表能量平衡及气候形成机制具有重要意义。利用中天山乌拉斯台地区陆气相互作用观测站2018年5月至2019年4月地表辐射数据,分析了中天山草地不同时间尺度和不同天气条件下的地表辐射与反照率变化特征。结果表明：(1)地表辐射月平均日变化除大气长波辐射较弱外,其余分量均呈单峰型,极值大小及时间存在差异,太阳总辐射与净辐射最大日峰值均出现在6月,为920.9与603.3 W/m~2,大气与地表长波辐射分别出现在7月和8月,为327.5 W/m~2与471.7 W/m~2,而反射短波辐射则出现在2月,为520.6 W/m~2。(2)太阳总辐射、反射短波辐射、大气与地表长波辐射年曝辐量分别为6860.62、2101.72、7171.25、10089.69 MJ/m~2;就季节变化而言,反射短波辐射曝辐量在冬季明显高于其它季节,其它分量则均表现为夏季>春季>秋季>冬季。(3)不同月份地表反照率日变化均呈“U”型曲线,年均值为0.393,最大与最小月均值分别出现在12月与8月,为0.760与0.217。这种变化体现在季节上则为冬季>秋季>春季>夏季。(...     

Radiobiological effects and medical applications of non-ionizing radiation

Radiation is used in medicine to diagnose and treat diseases but it can also cause harm to the body by burning or mutation. This depends on whether the radiation is ionizing or nonionizing. Despite its vast applications in surgery, dermatology and cosmetics, little is taught and thus known about non-ionizing radiation.This review article discusses the fundamentals of non-ionizing electromagnetic radiations. The main aim is to extensively explain the different types of non-ionizing radiation. This will equip students and medical personnel with knowledge on different medical applications and expose them to a variety of specializations in medicine that utilize non-ionizing radiation. The article discusses the physics, hazard, means of protection and medical application of each type of radiation: ultraviolet radiation, light (both visible light and LASER), infrared radiation, microwaves and extremely low frequency radiation separately. It presents these terms in a simple manner that avoids rigors mathematics and physics, which makes them comprehensible for medical students.The development of new diagnostic and therapeutic approaches could also lead to increased hazards to the body unless they are treated with precaution. If not adequately monitored, a significant health risk may be posed to potentially exposed employees. Hence proper dosage should be used for non-ionizing radiation. This is only possible through understanding of the risks/benefits of these radiations by studying the physics and radiobiological effects of each individual radiation.