Delayed fluorescence as a direct indicator of diurnal variation in quantum and radiant energy utilization efficiencies of phytoplankton

We compared delayed fluorescence (DF) excitation spectrometry with radiocarbon (¹⁴C) technique using a monoalgal culture of Chlorella vulgaris grown under natural temperature and irradiance. This was done by monitoring the DF, in parallel to quantum efficiency (QE) and index of radiant energy utilization efficiency (Ψ) as calculated on the basis of carbon uptake measurements by radiocarbon technique. During the diurnal cycle, temperature, irradiance, and chlorophyll (Chl) contents were monitored in the algal culture that was kept in an open transparent plastic tank submerged at the surface of Lake Kinneret, Israel. The DF signal correlated with both the QE (r ² = 0.869, p<0.01) and Ψ (r ² = 0.977, p<0.01) during a diurnal cycle. We suggest that, besides the measurement of active Chl and phytoplankton population composition, the DF signal provides additional information on the QE and Ψ in phytoplankton population.     

Modelling radiation fluxes in simple and complex environments—application of the RayMan model

The most important meteorological parameter affecting the human energy balance during sunny weather conditions is the mean radiant temperature T_mrt. It considers the uniform temperature of a surrounding surface giving off blackbody radiation, which results in the same energy gain of a human body given the prevailing radiation fluxes. This energy gain usually varies considerably in open space conditions. In this paper, the model ‘RayMan’, used for the calculation of short- and long-wave radiation fluxes on the human body, is presented. The model, which takes complex urban structures into account, is suitable for several applications in urban areas such as urban planning and street design. The final output of the model is, however, the calculated T_mrt, which is required in the human energy balance model, and thus also for the assessment of the urban bioclimate, with the use of thermal indices such as predicted mean vote (PMV), physiologically equivalent temperature (PET) and standard effective temperature (SET*). The model has been developed based on the German VDI-Guidelines 3789, Part II (environmental meteorology, interactions between atmosphere and surfaces; calculation of short- and long-wave radiation) and VDI-3787 (environmental meteorology, methods for the human-biometeorological evaluation of climate and air quality for urban and regional planning. Part I: climate). The validation of the results of the RayMan model agrees with similar results obtained from experimental studies.     

Antimicrobial effect of radiant catalytic ionization

The main purpose of micro-organisms elimination from the air and surfaces is to ensure microbiological safety in health care facilities or food production plants. Currently, many disinfection methods are used, both physical, chemical and, increasingly, biological. Scientists seek new solutions with high antimicrobial effectiveness (especially against the drug-resistant strains of bacteria), low production and operating costs, and, above all, the safety of patients and food consumers. The limitation of the methods used so far is primarily the micro-organisms acquire the resistance, mainly to antimicrobial agents. One of the new and alternative methods of disinfection is radiant catalytic ionization (RCI). RCI is an active method of air and surface purification. The technology proved high efficiency against viruses, Gram-positive and -negative bacteria, and fungi, both in the air and on surfaces (planktonic forms and biofilm). RCI has many advantages as well as some minor limitations. This overview summarizes the current knowledge about RCI technology.     

Secondary heat hyperalgesia detected by radiant heat stimuli in humans: Evaluation of stimulus intensity and duration

Diverging observations on secondary hyperalgesia to heat stimuli have been reported in the literature. No studies have investigated the importance of heat stimulus intensity and duration for the assessment of secondary heat hyperalgesia. The present study was designed to investigate systematically (1) if pain sensitivity to radiant heat stimuli (focused Xenon light) is altered in the area of secondary punctuate hyperalgesia induced by intradermal injection of capsaicin and (2) if heat stimulus duration and intensity had an influence on the ability to detect secondary heat hyperalgesia.

Pain ratings to radiant heat stimuli from a focused xenon lamp were assessed within the area of secondary punctuate hyperalgesia in fifteen volunteers before and after intradermal injection of capsaicin. The stimulus conditions were systematically varied between three intensity levels (0.8, 1.0 and 1.2?×?heat pain threshold (PT)) and four duration steps (200, 350, 500 and 750?ms). The present study shows that long duration (350–750?ms) and low intensity (0.8 and 1.0 ×?PT) radiant heat stimuli were adequate to detect secondary heat hyperalgesia.     

Quantum efficiencies,absolute intensities and signal‐to‐blackbody ratios of high‐temperature laser‐induced thermographic phosphors

There are a number of issues related to high‐temperature phosphor thermometry, which include measurement of faster decays, decreasing emission intensity and rising levels of blackbody radiation, that will impose limits on the maximum delectable temperature. This paper provides absolute intensity measurements, quantum efficiencies and signal‐to‐blackbody radiation ratios at peak emission wavelengths, at various temperatures (20–1400°C), for Y₂O₃:Eu, YAG:Tb and YAG:Tm thermographic phosphors under 266 and 355 nm excitation from a Q‐switched Nd:YAG laser. These terms are beneficial in a number of ways for engineers wanting to use a phosphor thermometry solution at high temperatures. They may also provide additional insight to the physical luminescence processes of phosphors at high temperatures. The phosphor signal:blackbody radiation ratio is useful because it combines the effects of blackbody radiation and phosphor emission intensities at various temperatures, providing a valuable quantitative evaluation that can be used as a design aid for phosphor selection. A figure of merit is the temperature when the blackbody radiation equals the phosphor emission (ratio = 1); this is the cross‐over temperature at which the blackbody radiation rapidly starts to overtake and mask out phosphor emissions. To the best of our knowledge no such work exists previously. The results presented show a variation in phosphor intensity with increasing temperature, and although the intensity and quantum efficiencies for Y₂O₃:Eu and YAG:Tb were much greater than YAG:Tm at low temperatures, YAG:Tm was found to be the most efficient phosphor investigated at higher temperatures (>900°C). With a peak emission wavelength of 458 nm, YAG:Tm experienced the lowest proportion of blackbody radiation therefore its advantage at higher temperatures was further amplified and was found to offer an advantage of approximately +350°C and +250°C increased upper temperature capability compared to Y₂O₃:Eu and YAG:Tb phosphors, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

Lipid-based capsaicin-loaded nano-colloidal biocompatible topical carriers with enhanced analgesic potential and decreased dermal irritation

Capsaicin (CP), a recent FDA-approved drug for the topical treatment of neuropathic pain, is associated with several side effects like irritation, burning sensation, and erythema, resulting in poor patient compliance. The present study is an attempt to study the effect of CP encasement in nano-lipoidal carriers (NLCs) on skin-transport characteristics, in vivo pharmacological performance, skin compliance, and stability of the finished product. The study also compares two methods of NLC preparation, namely microemulsification and rotary-evaporation for various attributes. The results demonstrated that microemulsion technique produced smaller nanoparticles vis-à-vis the rotary-evaporation method. Out of the various studied solid lipids, NLCs from stearic acid offered smallest size and the highest negative zeta potential. The NLC-gel offered higher skin permeation and skin retention of CP across LACA mice skin as compared with the conventional cream. The analgesic effect was observed to be enhanced substantially than that of the conventional cream when tested on a radiant mouse tail-flick model. The most alarming problems of skin-irritation and redness were successfully taken care by NLC-gel while the mice group receiving conventional cream showed marked changes in the skin histopathology. Besides the enhanced efficacy and decreased skin-irritation, the developed CP-NLCs also found to be stable and rheologically accepted formulation for the treatment of pain-associated disorders.     

CO2浓度和辐射强度变化对沙柳光合作用速率影响的模拟研究

沙柳是毛乌素沙地防护林的主要灌木树种 ,模拟研究沙柳对 CO2 浓度和辐射强度的响应有利于准确有效地制定全球变化下的沙漠化防治和水土流失的战略对策。结果表明 ,沙柳的光合作用速率对 CO2 浓度的响应表现为线性关系 ,对辐射的响应表现为对数函数关系。沙柳光合作用速率有随辐射强度增加和 /或 CO2 浓度的升高而增大的变化规律。CO2 浓度越高 ,沙柳的光合作用速率对辐射的反应越明显。同样 ,辐射越强 ,沙柳的光合作用速率对 CO2 浓度的反应越敏感。在高辐射条件下增加大气中 CO2 的“施肥效应”比低辐射条件下要显著。土壤干旱对沙柳的光合和暗呼吸都有抑制作用 ,使沙柳的生理过程受到影响 ,从而使沙柳对 CO2 浓度和辐射的反应规律不如土壤水分适宜时显著。     

地面覆盖对皮叶两用杜仲(Eucommia ulmoides Oliv.)林冠层辐射能分布的影响

通过在杜仲林地种植白三叶草、覆膜和覆秸秆,研究了地面覆盖对8a生皮叶两用杜仲林冠层光能分布的影响.结果表明:地面种植白三叶草、覆膜、覆秸秆和不覆盖条件下,林冠中部的总辐射分别比林冠表面降低了18.8%、20.0%、17.1%、17 1%;在林冠层,不同地面覆盖的林冠下表面接受的地面反射辐射差异较大,种植白三叶草、覆膜和覆秸秆的林冠下表面接收的反射辐射分别较地面无覆盖的高42.8%、56.4%和8.1%,且林冠中部接受的地面反射辐射明显低于林冠下表面;种植白三叶草、覆膜和覆秸秆的林冠中部的净辐射能分别较地面无覆盖的高14.4%、18.5%和5.6%.不同覆盖处理的冠层净辐射垂直分布趋势基本一致,在冠层范围内,净辐射能随高度升高呈指数规律增大.