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.     

Optimizing solar UV-radiation exposures for vitamin D3: comparing global and diffuse spectral UV radiation

Currently, there is a major gap in the knowledge that is needed to optimize the beneficial effects related to ultraviolet (UV) radiation at wavelengths that induce vitamin D(3) synthesis (UV(D3)) compared to reducing the biologically damaging overexposure to UV radiation. The aim of this study was to investigate the use of diffuse (radiation that is scattered from all directions) UV radiation to optimize exposures to UV(D3) radiation and maximize the reduction of exposure to UVA radiation. Data on global and diffuse solar UV-radiation spectra were collected at 10-min intervals in the Southern Hemisphere in the late spring and summer from 1 November 2006 to 28 February 2007. For a solar zenith angle (SZA) of approximately 5 degrees , the observed maximum UV(D3) irradiances were 0.80 W/m(2) and 0.46 W/m(2) for global and diffuse UV radiation, respectively. The observed maximum UVA irradiances were 79.0 W/m(2) and 36.2 W/m(2) for global and diffuse UV radiation, respectively. For diffuse UV radiation, the maximum ratio of vitamin D(3) to UVA radiation was 1.75% at a SZA of approximately 10 degrees , whereas the maximum ratio for global UV was 1.27% at 10 degrees . For SZAs of 25 degrees and less, more UV radiation is in the wavelength region contributing to vitamin D(3) synthesis (UV(D3)) than in the UVA region for diffuse UV radiation than for global UV radiation.     

人工同龄纯林冠层辐射场模拟模型 II.应用与验证

应用建立的人工同龄林辐射场模型对杉木 (Cunninghamialanceolata)人工林冠层辐射场进行了模拟 ,以实测的冠层辐射数据对模型进行了验证 ,对模型的不确定性以及叶面积密度和叶片散射的影响进行了计算和分析。结果表明 ,模拟和实测辐射场及日总量无显著差异 ,所建模型适于对杉木人工林冠层辐射的模拟。模型可能的误差来源包括树冠形状的不规则性、树冠大小和高低的不一致性、叶片在小范围内的簇生性等。考虑二维叶面积密度 (LAD)分布的模拟结果优于平均LAD。叶片的散射辐射约占总辐射的 3%～ 11%,且越靠近树冠里层和下部 ,散射作用越大。     

Emphasis of biological research for space radiation]

The paper summarized issues, current status and the recent topics in biological research of space radiation. Researches to estimate a risk associated with space radiation exposure during a long-term manned space flight, such as in the International Space Station, is emphasized because of the large uncertainty of biological effects and a complexity of the radiation environment in space. The Issues addressed are; 1) biological effects and end points in low dose radiation, 2) biological effects under low dose rate and long-term radiation exposure, 3) modification of biological responses to radiation under space environments, 4) various aspects of biological end points vs. cellular and molecular mechanisms, 5) estimation of human risk associated with radiation exposure in space flight, 6) regulations for radiation exposure limits for space workers. The paper also summarized and introduced recent progress in space related radiation researches with various biological systems.     

Biomarkers for human radiation exposure

There is a concern over the potential use of radioactive isotopes as a weapon of terror. The detonation of a radiation dispersal device, the so-called “dirty bomb” can lead to public panic. In order to estimate risks associated with radiation exposure, it is important to understand the biological effects of radiation exposure. Based on this knowledge, biomarkers to monitor potentially exposed populations after a radiological accident can be developed and would be extremely valuable for emergency response. While the traditional radiation exposure biomarkers based on cytogenetic assays serve as standard, the development of rapid and noninvasive tests for radiation exposure is needed. The genomics based knowledge is providing new avenues for investigation. The examination of gene expression after ionizing radiation exposure could serve as a potential molecular marker for biodosimetry. Microarray based studies are identifying new radiation responsive genes that could potentially be used as biomarkers of human exposure to radiation after an accident.     

Organ doses from radiation therapy in atomic bomb survivors

Previous surveys of radiation therapy among the Life Span Study (LSS) population at the Radiation Effects Research Foundation (RERF) revealed that 1,670 (1.4%) of the LSS participants received radiation treatments before 1984. The data on therapeutic radiation doses are indispensable for studying the relationship between radiation treatments and subsequent cancer occurrences. In this study, the radiation treatments were reproduced experimentally to determine the scattered radiation doses. The experiments were conducted using a female human phantom and various radiation sources, including a medium-voltage X-ray machine and a (60)Co gamma-ray source. Doses were measured using thermoluminescence dosimetry and ionization chambers. Radiation doses were determined for the salivary glands, thyroid gland, breast, lung, stomach, colon, ovary and active bone marrow. The results have been used for documenting the organ doses received by patients in previous surveys. The contribution of therapeutic irradiation to the occurrence of chromosome aberrations was studied using data on doses to active bone marrow from both radiation treatments and atomic bomb exposures in 26 RERF Adult Health Study participants. The results suggest that radiation treatments contributed to a large part of their frequencies of stable-type chromosome aberrations. The therapeutic radiation doses determined in the present study are available for investigating the effects of therapeutic irradiation on the subsequent primary cancers among atomic bomb survivors who received radiation treatments.     

Natural background radiation: problem of radionuclide migration and biological effects

Natural radiation background is the main contributor to radiation dose delivered to plants, animals, and man. That is why its effects are of increasing interest in radiobiology, radioecology, and radiation hygiene. The following problems are discussed: migration of main natural radionuclides in biosphere, dose formation, biological role of natural radiation background on the Earth, standards for natural radiation background, and problems of natural radiation background and biosphere evolution. The tasks of further radiobiological research in evaluating the role of natural radiation background are outlined.     

Estimation value of plasma amino acid target analysis to the acute radiation injury early triage in the rat model

Rapid radiation injury early triage for large-scale people after radiation exposure is vital for limited medical resources allocation and early treatment of a large number of wounded after a nuclear accident. Owing to the high-throughput analysis and minimally invasive of collection sample, radiation metabolomics has been recently applied to radiation damage researches. Here, exploration the feasibility of estimating the acute radiation injury early triage by means of plasma amino acid target analysis was attempted using high performance liquid chromatography–electrospray tandem mass spectrometry (HPLC–ESI–MS/MS) technique. The nonlinear kernel partial least squares (KPLS) model was used to classify the radiation damage levels. The classification accuracy of without radiation exposure was 92.3 % at 5 h after exposure. At 24 h after exposure, the triage accuracies were all above 83 % in the different doses of irradiated groups, the correct classification rates of moderate and severe radiation injury were 91.7 and 92.3 % respectively. At 72 h after exposure, the classification accuracies of all levels of radiation injury were more than 90 %, the correct classification rates of moderate and severe groups were up to 100 %. This approach is useful for early predicting different levels of radiation exposure and for developing metabolomics strategies for radiation biodosimetry in humans, but need more data to consummate.     

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。(...     

Medical countermeasures for radiation combined injury: radiation with burn, blast, trauma and/or sepsis. report of an NIAID Workshop, March 26-27, 2007

Non-clinical human radiation exposure events such as the Hiroshima and Nagasaki bombings or the Chernobyl accident are often coupled with other forms of injury, such as wounds, burns, blunt trauma, and infection. Radiation combined injury would also be expected after a radiological or nuclear attack. Few animal models of radiation combined injury exist, and mechanisms underlying the high mortality associated with complex radiation injuries are poorly understood. Medical countermeasures are currently available for management of the non-radiation components of radiation combined injury, but it is not known whether treatments for other insults will be effective when the injury is combined with radiation exposure. Further research is needed to elucidate mechanisms behind the synergistic lethality of radiation combined injury and to identify targets for medical countermeasures. To address these issues, the National Institute of Allergy and Infectious Diseases convened a workshop to make recommendations on the development of animal models of radiation combined injury, possible mechanisms of radiation combined injury, and future directions for countermeasure research, including target identification and end points to evaluate treatment efficacy.     

鸦胆子油乳联合放疗治疗鼻咽癌的临床疗效观察

目的:探讨鸦胆子油乳联合放疗治疗鼻咽癌的临床疗效及安全性。方法:将在我科就诊的154例鼻咽癌患者随机分为对照组和治疗组,治疗组患者在常规放射治疗的基础上联合鸦胆子油乳治疗,而对照组患者单纯接受常规放射治疗。待治疗结束后,观察并比较两组患者的临床疗效、血液学指标及不良反应的发生情况。结果:对照组和治疗组的临床有效率分别为63.16%、82.05%,治疗组的临床有效率明显高于对照组,两组间比较有统计学差异(P0.05)。治疗后,治疗组患者的血液学指标如白细胞计数、红细胞计数、血红蛋白水平、CD4+/CD8+等均显著高于对照组,不良反应如恶心呕吐、张口困难、吞咽困难、声音嘶哑、口腔炎均明显低于对照组,差异具有统计学意义(P0.05)。结论:鸦胆子油乳联合放射治疗能够有效提高鼻咽癌患者的临床疗效,并且降低放疗所致的各种不良反应,值得临床推广应用。     

Adaptive response to gamma radiation in mammalian cells proficient and deficient in components of nucleotide excision repair

Cells preconditioned with low doses of low-linear energy transfer (LET) ionizing radiation become more resistant to later challenges of radiation. The mechanism(s) by which cells adaptively respond to radiation remains unclear, although it has been suggested that DNA repair induced by low doses of radiation increases cellular radioresistance. Recent gene expression profiles have consistently indicated that proteins involved in the nucleotide excision repair pathway are up-regulated after exposure to ionizing radiation. Here we test the role of the nucleotide excision repair pathway for adaptive response to gamma radiation in vitro. Wild-type CHO cells exhibited both greater survival and fewer HPRT mutations when preconditioned with a low dose of gamma rays before exposure to a later challenging dose. Cells mutated for ERCC1, ERCC3, ERCC4 or ERCC5 did not express either adaptive response to radiation; cells mutated for ERCC2 expressed a survival adaptive response but no mutation adaptive response. These results suggest that some components of the nucleotide excision repair pathway are required for phenotypic low-dose induction of resistance to gamma radiation in mammalian cells.     

Molecular and cellular biology of moderate-dose (1-10 Gy) radiation and potential mechanisms of radiation protection: report of a workshop at Bethesda,Maryland, December 17-18, 2001

Exposures to doses of radiation of 1-10 Gy, defined in this workshop as moderate-dose radiation, may occur during the course of radiation therapy or as the result of radiation accidents or nuclear/radiological terrorism alone or in conjunction with bioterrorism. The resulting radiation injuries would be due to a series of molecular, cellular, tissue and whole-animal processes. To address the status of research on these issues, a broad-based workshop was convened. The specific recommendations were: (1) Research: Identify the key molecular, cellular and tissue pathways that lead from the initial molecular lesions to immediate and delayed injury. The latter is a chronic progressive process for which postexposure treatment may be possible. (2) Technology: Develop high-throughput technology for studying gene, protein and other biochemical expression after radiation exposure, and cytogenetic markers of radiation exposure employing rapid and accurate techniques for analyzing multiple samples. (3) Treatment strategies: Identify additional biological targets and develop effective treatments for radiation injury. (4) Ensuring sufficient expertise: Recruit and train investigators from such fields as radiation biology, cancer biology, molecular biology, cellular biology and wound healing, and encourage collaboration on interdisciplinary research on the mechanisms and treatment of radiation injury. Communicate knowledge of the effects of radiation exposure to the general public and to investigators, policy makers and agencies involved in response to nuclear accidents/events and protection/treatment of the general public.     

A global perspective of radiation-induced signal transduction pathways in cancer therapeutics

Radiation is a well established therapeutic modality for the treatment of solid tumors. By merging molecular biological approaches with radiation biology, a significant number of signaling events elicited by ionizing radiation have been delineated. These signaling pathways include events leading to cell cycle arrest, apoptosis or cell survival. There are two major signaling events that affect radiation response. One is the intrinsic/constitutive pro-survival signaling event that is present in proliferating tumor cells while the other is "induced pro-survival event" in response to radiation, both of these events confer resistance to the killing effects of radiation. In this review, signaling pathways that lead to either apoptosis or survival of cells following ionizing radiation are discussed in detail. In addition, mechanisms of action for gene/drug based inhibitors that modulate the expression and function of various genes and gene products involved in pro-survival signaling pathways are described. Further, novel strategies to abrogate the "induced radiation resistance" leading to enhanced therapeutic efficacy of ionizing radiation have been proposed. These novel strategies include the use of radio-gene therapy, low dose fractionated radiation therapy as a chemopotentiator and therapeutic utility of high radiation dose induced bystander effect. The complete understanding of the molecular pathways leading to apoptosis/survival of cells following ionizing radiation will help in tailoring more effective novel strategies and treatment modalities for complete eradication of cancer.     

Environmental radiation as the conditioning factor for the survival of yeast Saccharomyces cerevisiae

Whether natural radiation can be a conditioning factor for the growth and survival of a living organism was investigated using diploid yeast S. cerevisiae D7. Yeast cells were conditioned by growing them continuously for at least 100 generation in 3 different radiation background such as i) ambient radiation (1.1 mSv/y), ii) sub-ambient radiation (0.44 mSv/y, within a shielded chamber) and iii) an elevated background radiation (88 and 880 mSv/y in a gamma-field). At the end, the cells were challenged with 60Co gamma, 100 Gy and the viable fractions were determined. Conditioning the cells in 880 mSv/y and in ambient radiation, enabled the cells to reduce the deleterious effect of the challenging dose significantly (P < 0.05) compared to that of sub-ambient radiation. The cellular viability of yeast cultures seems to be influenced by the prevailing radiation background, apart from starvation. Comparatively, a rapid decline in viability was noticed when the cultures were incubated for 60 days in the shielded chamber. The results indicate that some amount of radiation equivalent to background level or little above is needed to confer fitness in biological systems against stress factors, including radiation. The adaptive dose for the diploid yeast was also determined by single exposure. The priming dose ranged from 0.01 to 1.2 Gy. An adaptive dose of 0.25 or 0.4 Gy, almost nullified the deleterious effect of the challenging dose. The adaptive response may have a greater role in the field of cancer therapy and in radiation risk assessment. Understanding the response of an organism at different radiation-background will be helpful for successful space management.     

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.     

Staged breast reconstruction with saline-filled implants in the irradiated breast: recent trends and therapeutic implications

A retrospective review was performed of one surgeon's experience with 40 consecutive patients who had undergone two-stage saline-filled implant breast reconstruction and radiation during the period from 1990 through 1997. A randomly selected group of 40 other two-stage saline-filled implant breast reconstructions from the same surgeon and time period served as controls. This review was undertaken because of the absence of specific information on the outcome of staged saline implant reconstructions in the radiated breast. Previously published reports on silicone gel implants and radiation have been contradictory. At the same time, the criteria for the use of radiation in the treatment of breast cancer have been expanded and the numbers of reconstruction patients who have been radiated are increasing dramatically. For example, in a 1985 report on immediate breast reconstruction, only 1 of 185 patients over a 6-year period underwent adjuvant radiation therapy, whereas in this review, there were 40 radiated breasts with saline-filled implants, 19 of which received adjuvant radiation therapy during their expansion. The study parameters included patient age, breast cup size, implant size, length of follow-up, number of procedures, coincident flap operations, Baker classification, complications, opposite breast procedures, pathologic stage, indications for and details about the radiation, and outcomes. The use of radiation in this review of reconstructed breasts can logically be divided into four groups: previous lumpectomy and radiation (n = 7), mastectomy and radiation before reconstruction (n = 9), mastectomy and adjuvant radiation during reconstruction/expansion (n = 19), and radiation after reconstruction (n = 5). The largest and most rapidly growing group of patients is of those receiving postmastectomy adjuvant radiation therapy. A total of 47.5 percent (19 of 40) of radiated breasts with saline implants ultimately needed the addition of, or replacement by, a flap. Ten percent of a control group with nonradiated saline implant reconstructions also had flaps, none as replacements. Fifty percent or more of both the radiated and control groups had contralateral surgery. Complications were far more common in the radiated group; for example, there were 32.5 percent capsular contractures compared with none in the control group. The control nonradiated implant-only group and the flap plus implant radiated group did well cosmetically. The radiated implant-only group was judged the worst. The increasing use of radiation after mastectomy has important implications for breast reconstruction. The possibility for radiation should be thoroughly investigated and anticipated preoperatively before immediate breast reconstruction. Patients with invasive disease, particularly with large tumors or palpable axillary lymph nodes, are especially likely to be encouraged to undergo postmastectomy radiation therapy. The indications for adjuvant radiation therapy have included four or more positive axillary lymph nodes, tumors 4 cm (or more) in diameter, and tumors at or near the margin of resection. More recently, some centers are recommending adjuvant radiation therapy for patients with as few as one positive lymph node or even in situ carcinoma close to the resection margin. The use of latissimus dorsi flaps after radiation has proven to be an excellent solution to postradiation tissue contracture, which can occur during breast expander reconstruction. The use of the latissimus flap electively with skin-sparing mastectomy preradiation is probably unwise, unless postmastectomy radiation is unlikely. Skin-sparing mastectomy with a latissimus flap thus should be preserved for patients unlikely to undergo adjuvant radiation therapy. Purely autologous reconstruction such as a TRAM flap is another option for these patients, either before or after radiation therapy.     

High Mortality of Red Sea Zooplankton under Ambient Solar Radiation

High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation). The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM) 18.4±5.8% h⁻¹, five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½of maximum values averaged (±SEM) 12±5.6 h⁻¹% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean.     

The survival of mice and the metallothionein content of their livers and kidneys as criteria for assessing exposure to pulsed neutron radiation

The effect of pulsed neutron radiation was studied in comparison with continuous neutron radiation and continuous gamma-radiation. Animal survival and induction of metallothionein (MT) synthesis in liver and kidney of mice exposed to equivalent doses were chosen as criteria for evaluation of radiation effects. It was found that the level of MT in liver and kidney of mice exposed to neutron radiation decreased 24 hours after irradiation and then continued decreasing in kidney for 48 hours after irradiation. This is evidence of more intensive free-radical processes initiated by pulsed neutron radiation. At the same time, RBE values of pulsed neutrons did not differ significantly from that of continuous neutron radiation.