Biostimulation of HeLa cells by low-intensity visible light

Summary The action spectra of low-intensity light in the range from 300 to 900 nm on the synthesis rate of nucleic acids in the culture of HeLa cells has been measured. The synthesis of DNA and RNA is stimulated in several spectral intervals with maxima nearby 400, 630, 680, 760 and 820 nm. The stimulation effect is very sensitive to the irradiation duration (light intensity) at a fixed dose. The dose that causes the maximal stimulation is approximately 10 times smaller in the near-UV blue region than in red-IR region.

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Riassunto Si è misurato lo spettro d’azione della luce a bassa intensità nell’intervallo da 300 a 900 nm sul tasso di sintesi degli acidi nucleici in culture di cellule HeLa. La sintesi di DNA ed RNA è stimolata in parecchi intervalli spetrali con massimi vicino a 400, 630, 680, 760 e 820 nm. L’effetto di stimolazione è molto sensibile alla durata d’irradiazione (intensità della luce) ad una dose fissa. La dose che causa la stimolazione massima è approssimativamente dieci volte piú piccola nella regione blu dell’ultravioletto vicino che nella regione del rosso-infrarosso.

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Резюме Измерен спектр действия низкоинтенсивного света в диапазоне (300⋎900) нм на скорость синтеза нуклеиновых кислот в культуре клеток HeLa 1.5 часа после облучения. Синтез ДНК и РНК стимулируется в несколбких спектральных интервалах с максимумами вблизи 400, 630, 680, 760 и 820 нм. Эффект стимуляции очень чувствителен к продолжительности облуения (интенсивности света) при фиксированной дозе. Доза, при которой наблюдается максимальная стимудяция, в несколько ваз меньше в ближнеи УФ-синей области с максимумом около 400 нм.

     

Biostimulation of HeLa cells by low-intensity visible light

Summary A culture of HeLa cells was subjected to concurrent and consecutive dichromatic irradiation with visible light of various wavelengths. Consecutive dichromatic irradiation in the sequence 760 nm+633 nm was found to stimulate the synthesis of DNA in the cells and that in the sequence 633 nm+760 nm to inhibit it. These effects reached their maxima when the time interval between the successive irradiation events came to (1⋎3) min. On the strength of these data it is supposed that in HeLa cells there may exist a photochromic, photoreversible pigment similar to photochrome. Based on the results of dichromatic irradiation with blue and red light, flavoproteins are being discussed as likely photoreceptors.

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Una cultura di cellule HeLa è stata sottoposta ad irradiazione dicromatica concomitante e consecutiva con luce visibile di varie lunghezze d'onda. Si è trovato che l'irradiazione dicromatica consecutiva nella sequenza 760 nm+633nm stimola la sintesi del DNA nelle cellule e quella nella sequenza 633 nm+760 nm la inibisce. Questi effetti raggiungono i valori massimi quando l'intervallo di tempo tra irradiazioni successive arriva a (1⋎3) min. Sulla base di questi dati si suppone che nelle cellule HeLa possa esistere un pigmento fotocromatico fotoreversibile simile al fotocromo. In base a questi risultati di radiazione dicromatico con luce blu e rossa, le flavoproteine sono discusse come fotorecettori similari.

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Резюме Проведено одновременное и последовательное дихромное облучение клеток НеЛа различными длинами волн видимой области спектра. Скорость синтеза ДНК стимулируется при последовательном облучении (760+633) нм и инлибирыется при последовательности (633+760) нм. Эффекты являются максимальными когда интервал между лблучениями составляет (1⋎3) мин. На основе зтих данных предполагается существование в клетках ХеЛа фотохромното фотообратимого питмента типа фитохрома. На основе данных о дихромном облученим и красным светом в качестве возможных фоторецепторов обсуждаются флавпротеиды.

     

Biostimulation of HeLa cells by low-intensity visible light. V. Stimulation of cell proliferationin vitro by He−Ne Laser irradiation

Summary Autoradiographic experiments, performed with monolayer HeLa cells, show that the irradiation with He-Ne laser (D=100 J/m²) causes an increase in the number of S-phase cells connected with enhanced G₁-S transition of a part of the population, as well as an increase in the grain count on the labelled nuclei connected with an enhancement of DNA synthesis in Sphase cells. The irradiation influences the proliferation rate of various subpopulations not in equal degree, as shown analysing the clone size distribution after the irradiation (D=10, 10², 10³J/m²). The stimulative effect of irradiation is most noticeable on the proliferation activity of the slowly growing subpopulations.

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Riassunto Esperimenti autoradiografici, attuati su un monostrato di cellule HeLa, mostrano che l’irraggiamento con un laser He-Ne (D=100J/m²) causa l’aumento del numero delle cellule in fase S connesso con un aumento della transizione G₁-S di una parte della popolazione, nonché l’aumento dei granuli nei nuclei marcati, connesso con un aumento della sintesi del DNA nelle cellule in fase S. L’irraggiamento influenza la velocità di proliferazione di varie sottopopolazioni non in misura uguale a quella mostrata analizzando la distribuzione delle dimensioni del clone dopo l’irraggiamento (D=10, 10², 10³J/m²). L’effetto stimolatorio dell’irraggiamento si nota di piú sull’attività proliferativa delle sottopopolazioni in crescita lenta.

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Резюме Авторадиографические эксперименты, проведенные с монослоем клеток HeLa показали, что облучение He-Ne лазером (D=100 ДжМ²) приводит к увеличению количества клеток вS-фазе, связанному с ускорением перехода части популяции изG ₁ вS-фазу. Также отмечено увеличение количства зерен в меченых ядрах, связанное с ускорением синтеза ДНК в клеткахS-фазы. Облучение влияет на скорость пролиферации различных субппопуляций в разиой степени как показал анализ распределения размеров клонов после облученияD=10, 10², 10³ Дж/М². Эффект стимуляции пролиерации наиболее заметен в случае медленно растуших субпопуляций.

     

Visualization of mitotic HeLa cells by advanced polarized light microscopy

The conventional polarized light imaging system can observe sub-microscopic molecular order non-destructively, quantitatively and without labeling or staining. Recently, a more sophisticated version, Abrio imaging system, than the conventional polarized light imaging system, was developed. This advanced polarized light imaging system has simplified the process of birefringent imaging, higher sensitivity and accuracy irrespective of sample orientation. By performing time-lapse observations using the advanced polarized light microscopy, we visualized mitotic spindles, especially kinetochore microtubules, of HeLa cells. Moreover, we successfully visualized the detailed structure of several filament bundles, which possibly are components of the contractile ring. Here, we report the potential of advanced polarized light imaging systems for imaging mitotic HeLa cells and the new insights obtained during this microscopic study.     

低强度激光辐照HeLa细胞诱导增殖效应的可见光谱特性

比较研究了可见波段405,514,633和785nm低强度激光辐照HeLa细胞的促增殖效应。实验采用100和1 000J.m-2两种有效能量密度的可见光波辐照细胞,照射后24,48,72h采用MTT法检测细胞活性。结果表明,405,633,785nm激光均能促进HeLa细胞增殖,且呈波长和时间依赖性;633nm激光辐照对细胞促增殖效应最显著;514nm激光辐照对HeLa细胞促增殖效应较不明显。不同光剂量对细胞增殖效应不同,405,633,785nm激光辐照时能量密度为1 000J.m-2的辐照组细胞增殖均较100J.m-2辐照组明显,而514nm激光辐照时1 000J.m-2辐照组与100J.m-2辐照组细胞增殖的差异不明显。     

编码源中子成像的可见光模拟

采用编码源能大大提高中子成像的中子注量率,同时保持较高的准直比。对改进的均匀冗余矩阵编码源中子成像进行了计算机模拟并利用可见光进行了实验,初步验证了编码源中子成像的可行性,并且探索了各种在非理想条件下成像对图像质量的影响并提出了解决方法。结果表明,编码源配合相关算法能够较好地重建图像,反解后的物体尺寸及分辨能力与单孔成像相当,同时缩短了曝光时间。若物体与理想成像面存在着位置或旋转偏差,则投影大小与探测器CCD像素、解码矩阵尺寸便不能对齐,但仍可以通过对图像背景噪声标准差的计算来后期修正图像,也可以利用此方法在实验前确定编码源成像系统中理想成像面的位置,以确保图像质量。     

Indoor positioning modeling by visible light communication and imaging

This letter presents a model of an indoor light positioning system(LPS) based on white LEDs and a camera.The position of an LPS receiver is determined through both its relative position to LEDs according to their images captured by the camera and LEDs' absolute position information in the navigation frame, obtained through a visible light communication(VLC) link. The error performance of the proposed LPS is analyzed.The mean error and mean square error(MSE) of estimated receiver position using least squares(LS) and weighted least squares(WLS) estimators are both derived in the presence of non-uniform measurement bias and white Gaussian noise. The effects of communication data rate on the positioning accuracy are also studied through BER performance.     

Ga掺杂对ZnO纳米结构可见光发射的抑制效应

采用碳热还原反应和原位掺杂的方法制备了不同Ga掺杂浓度的ZnO纳米结构. X射线衍射 显示掺杂纳米结构中为单一的氧化锌纤锌矿结构. 扫描电子显微镜 观测发现随掺杂浓度的增大, 纳米结构的形貌逐渐从纳米六棱柱变为纳米锥.光致发光 和X射线光电子能谱 测量分别发现随着掺杂浓度升高, 纳米结构的可见发光强度和其中空位 氧峰相对强度逐渐减小直至消失, 两者存在很强的相关性. 上述结果为ZnO可见光发射的氧空位机理提供了新的实验证据. 对Ga掺杂抑制纳米结构中氧空位的原因进行了分析.     

The polymerization of acryl pentaerythrol derivatives initiated by visible light

The photopolymerization of pentaerythrol triacrylate and its chloroacetyl derivative under the action of visible light in the presence of a camphorquinone initiator was studied in real time. Photopolymerization occurred at a low rate with a 40% monomer conversion. The introduction of the chloroacetate group accelerated polymerization only insignificantly, but monomer conversion remained unchanged. The use of donor-acceptor initiating systems (tert-aminocamphorquinone) increased the rate of polymerization by approximately an order of magnitude. The main reason for this effect was an increase in the quantum yield of initiator photodissociation in the presence of tert-amines. The rate of the polymerization of monomers did not correlate with the ionization potentials of amines and, therefore, the rate of radical generation. The camphorquinone-amine system formed a quaternary salt with pentaerythrol triacrylatechloroacetate. This salt hindered exciplex formation.     

红外激光对可见光CCD成像系统的干扰

采用连续波红外激光对可见光面阵CCD成像系统进行了干扰实验,观察到饱和串扰、全屏饱和等干扰现象,并测到串扰阈值小于2.0×102W/cm2,全屏饱和阈值为1.2×104W/cm2。通过分析CCD输出电压、视频信号,提出基于有效干扰面积的干扰效果评估方法,并利用该方法对干扰面积与激光功率密度、辐照时间之间的关系进行了半定量分析。结果显示:激光功率密度对干扰效果的影响较大,而辐照时间在0.5~2.0 s之间时,辐照时间对CCD干扰效果的影响不明显。     

Optical nonlinearity in thin films exposed to low-intensity light

Optical nonlinearity in semiconducting and insulating thin-film structures is studied by waveguide methods under self-action conditions at a light intensity less than 0.1 W/cm² and a wavelength of 630 nm. The optical properties vs. light intensity are similar for semiconducting and insulating films, multilayer thin-film structures, and semiconductor-doped glass films. It is demonstrated that the optical nonlinearity and the nonlinear optical constants depend on the interface condition.     

红外激光对可见光CCD成像系统的干扰

采用连续波红外激光对可见光面阵CCD成像系统进行了干扰实验,观察到饱和串扰、全屏饱和等干扰现象,并测到串扰阈值小于2.0×102 W/cm2,全屏饱和阈值为1.2×104 W/cm2。通过分析CCD输出电压、视频信号,提出基于有效干扰面积的干扰效果评估方法,并利用该方法对干扰面积与激光功率密度、辐照时间之间的关系进行了半定量分析。结果显示：激光功率密度对干扰效果的影响较大,而辐照时间在0.5～2.0 s之间时,辐照时间对CCD干扰效果的影响不明显。     

Selective reduction of nitroaromatic compounds on silver nanoparticles by visible light

For the first time, we report experimentally and theoretically that nitroaromatic compounds, 2,4‐dinitrobenzenethiol and 4‐chloro‐2‐nitrobenzenethiol, on silver sols can be selectively reduced to 2‐amino‐4‐nitrobenzenethiol and 2‐amino‐4‐chlorobenzenethiol simply by irradiating with a visible light in ambient conditions, and the selective photoreduction is a very facile process. The results of quantum chemical calculations are in good agreement with our experimental data. Copyright © 2012 John Wiley & Sons, Ltd.     

Macroscopic invisibility cloak for visible light

Invisibility cloaks, a subject that usually occurs in science fiction and myths, have attracted wide interest recently because of their possible realization. The biggest challenge to true invisibility is known to be the cloaking of a macroscopic object in the broad range of wavelengths visible to the human eye. Here we experimentally solve this problem by incorporating the principle of transformation optics into a conventional optical lens fabrication with low-cost materials and simple manufacturing techniques. A transparent cloak made of two pieces of calcite is created. This cloak is able to conceal a macroscopic object with a maximum height of 2 mm, larger than 3500 free-space-wavelength, inside a transparent liquid environment. Its working bandwidth encompassing red, green, and blue light is also demonstrated.     

A Fourier spectrometer for visible light

A Michelson interferometer incorporating the modifications of Sternberg and James, ⁽¹⁾ which is used as a Fourier spectrometer for visible light, has been built. The well-known difficulties due to the small wavelength of visible light were overcome by kinematic hinges strictly applied in the mechanical construction, by a special hydraulic drive to change the optical path and by thorough checks of the picked up interferogram with a microprocessor. The results are discussed.     

Multi-hop relay-based maritime visible light communication

This Letter presents a multi-hop relay visible light communication(VLC) system for maritime applications.Maritime VLC systems suffer from limited coverage distance due inherently to the usage of light-emitting diodes and photodetectors. The proposed system employs a multiple of decode-and-forward relays to extend coverage distance in maritime environments. The multi-hop relay based maritime VLC is analyzed under a maritime channel modeled by the JONSWAP spectrum and gamma–gamma distribution. It is found that the use of relays in maritime environments can extend the coverage distance significantly and also improve the performance. In addition,the performance of the system is analyzed using various combining techniques at the receiver to enhance the performance. The maximal ratio combining technique is found to provide superior link quality in maritime environments.     

可见光CCD的光致过饱和现象

 报道了可见光CCD的过饱和状态——在强光辐照下,CCD输出图像中的白色饱和区域内出现黑色盲区。介绍了相机成像系统的信号处理过程和CCD的4种基本输出波形,给出了这4种波形的信号在经过相关双采样电路处理之后的结果和对应的CCD的4种基本输出图像效果,即无光照的黑区、弱光照的灰区、光照饱和的白区和强光致过饱和的黑色盲区（即过饱和状态）。过饱和状态CCD的输出信号波形中,复位电平发生改变而与处于饱和的数据电平持平,使该信号在经过相关双采样电路处理后变为零输出,造成CCD输出图像中的白色饱和光斑中间出现黑色盲区。     

可见光隐身涂料设计

根据颗粒粒径与波长相比的不同情形，分别用粗粒子理论、细粒子理论和桥理论求得颗粒的 光散射系数和吸收系数，从而得到含颗粒涂料的漫反射率.讨论了涂料参数如黏结剂和颗粒 的光学常数、颗粒粒径和体积比等对漫反射率的影响.并以含钛白粉颗粒的涂料为例，介绍 了可见光隐身涂料的计算机设计方法. 关键词： 非均匀涂料 涂料设计 可见光隐身     

可见光波段超材料的平面聚焦效应

基于超材料双鱼网结构物理模型,设计了树枝状结构+树枝状结构、树枝状结构+银膜和树枝状结构+氧化铟锡玻璃三种可见光波段超材料复合结构.采用双模板辅助化学电沉积方法,制备出金属银树枝状结构阵列和银膜,分别实现了这三种复合结构.透射和反射实验表明,三种复合结构具有类似的行为.比较发现,树枝状结构+氧化铟锡玻璃复合结构具有损耗低和平面聚焦效应明显的优点.通过调节实验条件,分别制备出能够实现平面聚焦的红绿蓝三种可见光波段超材料. 关键词： 超材料 银树枝状结构 可见光 平面聚焦     

Perturbations of the periodicity of plant leaflet oscillations caused by visible light

Lateral leaflet movements in the presence of blue and white light stimuli in the plant Desmodium gyrans have been studied. A strong effect, namely, the reduction of amplitude of the lateral leaflet movement and thus a shortening period was observed. The oscillations regained their same regularity over a few cycles after the stimulus was removed and they quickly halted when the lateral leaflets were exposed to a light of higher intensity. However, the blue light was found to be more effective than the white light in the perturbation of leaflet oscillations. The results were discussed by reviewing the investigations performed in this plant with other stimuli.