共查询到20条相似文献,搜索用时 15 毫秒
1.
Despite encouraging progress in recent years, our knowledge of the natural history of Waldenstr?m macroglobulinemia (WM), a low-grade LPL (lymphoplasmacytic lymphoma) of mature IgM+ B-lymphocytes, remains superficial. This is particularly true of the etiology of WM (tumor causation and initiation) and the sequence of events that underlie the malignant transformation of precursor B cells (tumor progression). Here we briefly review the epidemiology of and genetic predisposition to WM and consider the role of autoimmunity and chronic inflammation in related tumor development. We discuss the immunophenotypic features of WM, including the immunological specificity of WM-associated IgM paraproteins. The proclivity of patients with WM to develop the rare immunoglobulin autoantibody syndromes mixed IgM-IgG cryoglobulinemia, chronic cold agglutinin disease, and IgM neuropathy will also be discussed. We conclude with a call for additional research to elucidate outstanding questions, such as the role of T cell-dependent vs. –independent immune responses in the pathophysiology of WM. 相似文献
2.
Waldenstr?m macroglobulinemia (WM) is a low-grade lymphoplasmacytic lymphoma of mature IgM+ B-lymphocytes that remains incurable despite recent practice-altering therapeutic advances and refinements in patient care. Defining features of WM include symptoms that can either be attributed to the extent and site of tissue infiltration by tumor cells or the magnitude and immunological specificity of the monoclonal serum IgM (paraprotein). Current guidelines for the therapeutic stratification of patients with newly diagnosed WM recommend BR (bendamustin-rituximab) for bulky and/or symptomatic disease. DRC (dexamethasone-rituximab-cyclophosphamide) is a good treatment option for relapsed or refractory WM. Ibrutinib – a small-drug inhibitor of Bruton tyrosine kinase, approved for WM treatment in the United States and Europe in 2015 – is particularly effective for tumors that harbor the hallmark MYD88L265P mutation. Plasma exchange is indicated in patients with IgM-dependent hyperviscosity syndrome. The potential development of novel drugs and combination regimens generates promise that the future of patients with WM is bright. 相似文献
3.
Waldenstr?m macroglobulinemia (WM) is a neoplasm of mature IgM-expressing B-lymphocytes that is characterized by the occurrence of a monoclonal IgM (mIgM) paraprotein in blood serum and the infiltration of hematopoietic bone marrow with malignant lymphoplasmacytic cells. WM remains incurable despite the development of new therapeutic options. Owing in large measure to having a low incidence, indolent clinical course and good long-term control with proper clinical management, WM has not been investigated as extensively as other B-lineage neoplasms. Major knowledge gaps in our understanding of the natural history of WM include the cell of origin. With that shortcoming in mind, here we discuss the significance of a specific gain-of-function mutation in the adapter protein, myeloid differentiation primary response 88 (MYD88), that occurs with near-complete penetrance in WM and suggests that tumor development is under strong selective pressure for elevated MYD88 signaling. This provides an intriguing link to IgM memory B-cells, which comprise two types of B-lymphocytes ( natural effector IgM+IgD+ cells and IgM-only IgM+IgD- cells ) that depend, in part, on MYD88 signaling and constitute intriguing candidates for WM’s cell of origin. We review the features and developmental history of IgM memory in greater depth and propose that WM may be derived from primitive innate-like B-cells ( marginal zone B-cells and B1 B-cells ) that feed the IgM memory compartment. We conclude with a model of MYD88-dependent tumor development in the mature B-cell lineage that considers two different ( convergent or divergent) oncogenesis pathways with respect to the cells of origin. 相似文献
4.
Global climate change is one of the most important issues of contemporary environmental safety. Quantifying regional or global greenhouse gas (GHG) emissions and searching for appropriate mitigation measures have become a relatively hot issue in international global climate change studies. The high temporal and spatial variability of GHG emissions from soils makes their field measurement at regional or national scales impractical. To develop emission factors for a wide range of management practices such as those given in the Intergovernmental Panel on Climate Change Tier I methodology are often considered as a convenient technique to estimate emissions, but these can result in substantial errors when applied to specific geographical regions. Accordingly, considering the complexity of greenhouse gas production in soils, process-based models are required to quantify and predict the GHG emissions, and also interpret the intricate relationships among the gas emissions, the environmental factors and the ecological drivers. Several detailed biogeochemical process-based models of GHG emissions have been developed and accepted in recent years to provide regional scale estimate of GHG emissions and assess the mitigation measures. Among these the DNDC (Denitrification–Decomposition) model, as a process-based biogeochemical model, is capable of predicting the soil fluxes of all three terrestrial greenhouse gases: nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4), as well as other important environmental and economic indicators such as crop production, ammonia (NH3) volatilisation and nitrate NO3- leaching. Originally developed as a tool to simulate GHG emissions generated from agro-ecosystem, DNDC has since been expanded to include ecosystems such as rice paddies, grazed pastures, forests, and wetlands, and the model has attracted worldwide attention to simulate carbon and nitrogen biogeochemical cycles occurring in global ecosystems. This paper introduces the scientific basis underlying the modeling of greenhouse gas emissions from terrestrial soils, brings together the worldwide research undertaken on a wide range of ecosystems to test and verify, improve and modify, and apply the DNDC model to estimate GHG emissions from these systems, and furtherly sums up the advantages and disadvantages of the model for providing a reference for the application and development of the model. Most studies showed that there was a good agreement between the simulated and observed values of CO2, CH4 and N2O emissions from arable, forest and grassland fields at different geographical locations over the world. However, some discrepancies still existed between observed and simulated seasonal patterns of CH4 and N2O emissions. Moreover, the DNDC model was mainly tested against experimental data on GHG emissions, but there were a few validations on NO3- leaching, soil water dynamics, NH3 volatilisation which could greatly impact the GHG emissions. With the high development of society and economy, China had been facing a huge challenge between food production and environmental protection. Therefore, it was an urgent task to search optimal measures for optimizing land resource use, increasing crop productivity and reducing adverse environmental impacts. Process-based biogeochemical modeling, as with DNDC, can help in identifying optimal strategies to meet the needs. In future, the DNDC model need to not only improve the capability of predicting the GHG emissions, but also the accuracy of simulating the NO3- leaching and soil water dynamics for quantifying the non-point source pollution through modifying the parameters of the model or combining with other models, as SWAT model. The DNDC model will play more and more important role in future studies on global change. 相似文献
5.
Advance in a terrestrial biogeochemical model—DNDC model 总被引:1,自引:0,他引:1
Global climate change is one of the most important issues of contemporary environmental safety. Quantifying regional or global greenhouse gas (GHG) emissions and searching for appropriate mitigation measures have become a relatively hot issue in international global climate change studies. The high temporal and spatial variability of GHG emissions from soils makes their field measurement at regional or national scales impractical. To develop emission factors for a wide range of management practices such as those given in the Intergovernmental Panel on Climate Change Tier I methodology are often considered as a convenient technique to estimate emissions, but these can result in substantial errors when applied to specific geographical regions. Accordingly, considering the complexity of greenhouse gas production in soils, process-based models are required to quantify and predict the GHG emissions, and also interpret the intricate relationships among the gas emissions, the environmental factors and the ecological drivers. Several detailed biogeochemical process-based models of GHG emissions have been developed and accepted in recent years to provide regional scale estimate of GHG emissions and assess the mitigation measures. Among these the DNDC (Denitrification–Decomposition) model, as a process-based biogeochemical model, is capable of predicting the soil fluxes of all three terrestrial greenhouse gases: nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4), as well as other important environmental and economic indicators such as crop production, ammonia (NH3) volatilisation and nitrate NO3- leaching. Originally developed as a tool to simulate GHG emissions generated from agro-ecosystem, DNDC has since been expanded to include ecosystems such as rice paddies, grazed pastures, forests, and wetlands, and the model has attracted worldwide attention to simulate carbon and nitrogen biogeochemical cycles occurring in global ecosystems. This paper introduces the scientific basis underlying the modeling of greenhouse gas emissions from terrestrial soils, brings together the worldwide research undertaken on a wide range of ecosystems to test and verify, improve and modify, and apply the DNDC model to estimate GHG emissions from these systems, and furtherly sums up the advantages and disadvantages of the model for providing a reference for the application and development of the model. Most studies showed that there was a good agreement between the simulated and observed values of CO2, CH4 and N2O emissions from arable, forest and grassland fields at different geographical locations over the world. However, some discrepancies still existed between observed and simulated seasonal patterns of CH4 and N2O emissions. Moreover, the DNDC model was mainly tested against experimental data on GHG emissions, but there were a few validations on NO3- leaching, soil water dynamics, NH3 volatilisation which could greatly impact the GHG emissions. With the high development of society and economy, China had been facing a huge challenge between food production and environmental protection. Therefore, it was an urgent task to search optimal measures for optimizing land resource use, increasing crop productivity and reducing adverse environmental impacts. Process-based biogeochemical modeling, as with DNDC, can help in identifying optimal strategies to meet the needs. In future, the DNDC model need to not only improve the capability of predicting the GHG emissions, but also the accuracy of simulating the NO3- leaching and soil water dynamics for quantifying the non-point source pollution through modifying the parameters of the model or combining with other models, as SWAT model. The DNDC model will play more and more important role in future studies on global change. 相似文献
6.
XIAO Jia 《生物化学与生物物理进展》2023,50(8):1781-1781
Lycium barbarum is a traditional Chinese medicinal plant that has been widely used as a functional food and dietary supplement. Lycium barbarum polysaccharide (LBP) is an important active substance found in Lycium barbarum[1]. It has been recorded in the “Ben Cao Gang Mu (Compendium of Materia Medica)” to have anti-aging and skin whitening effects. Previous studies have
focused on its antioxidant properties to explain its efficacy[2]. However, the scientific understanding of the anti-aging and skin whitening effects of LBP, especially the underlying mechanisms, is still unclear. Wu et al. (Prog Biochem Biophys, 2023, 50(8): 1926-1936. DOI: 10.16476/j. pibb. 2023.0219) investigated the new function and mechanism of LBP1C, which is extracted from Lycium barbarum. This specific extract was found to delay cell senescence by promoting autophagy, thereby achieving the effects of anti-aging and skin whitening. As the era of aging approaches, the development of anti-aging drugs and strategies is now more focused on promoting healthy aging[3]. This study demonstrated that LBP1C improved the motor ability of C. elegans during aging, promoting healthy aging. Mechanistically, LBP1C increased autophagy by promoting TFEB nuclear translocation, while reducing the accumulation of SASP and lipofuscin in cells and C.elegans. These findings provide new scientific evidence for understanding the efficacy of “skin whitening”. With age, the malfunctioning of autophagy can lead to the loss of proteostasis. Therefore, exploring direct modulators of autophagy is a promising approach for geroprotective interventions[4]. LBP1C, as a natural autophagy activator, shows potential application prospects in this field.
This study has revealed the potential of LBP1C extracted from Lycium barbarum in terms of antiaging and skin whitening effects by activating autophagy. These findings provide a scientific and theoretical foundation for further research in clinical applications. Consulting Lycium barbarum as a medicinal and food source offers promising opportunities for translation. However, despite the credible and comprehensive research conducted by Wu et al., there are still certain unresolved issues. For example, the mechanism by which LBP1C regulates TFEB nuclear translocation requires further exploration, and the effects of LBP1C on humans remain unexplored. In conclusion, this study utilizes modern scientific technology to elucidate the principles of traditional Chinese medicine. Given the contemporary need for healthy aging, the potential application of LBP1C is tremendous, offering exciting prospects for following translational studies. 相似文献
7.
Chun-Ming Liu 《植物学报(英文版)》2015,57(4):326-327
<正>The purpose of scientific journals is to serve as a public depository for research endeavors,allowing people to share research results and opinions with their peers.In the fastdeveloping modern world,various tools are available to evaluate the track record,or publication profile of a scientist.Pursuits to achieve research results that are published in the highest impact factor(IF)journals has often 相似文献
8.
Marie F. Moreau Janie Surico-Bennett Marie Vicario-Fisher David Crane Russel Gerads Richard M. Gersberg Stuart H. Hurlbert 《Hydrobiologia》2007,576(1):127-165
A summary of all existing information collected since 1980 on contaminants in tilapia from the Salton Sea is presented and
risks to humans and fish-eating birds assessed. Of the 17 trace elements, 42 organic pesticides and 48 polychlorinated biphenyls
(PCBs) analyzed in tilapia whole body and fillet samples, only selenium (Se), arsenic (As) and possibly dichlorodiphenyltrichloroethane
(DDE) were found at levels high enough to be of concern for fish, birds or humans. Average current concentration of arsenic
(As) was 0.7 μg g−1 wet weight (ww) in whole body samples and 1.2 μg g−1 ww in fillet samples, or 2.8 and 5.7 μg g−1 dry weight (dw), respectively. Inorganic As averaged 0.006 μg g−1 ww (0.03 μg g−1 dw) in fillet samples, which represented 0.3% of total As. By U.S. Environmental Protection Agency (U.S.EPA) guidelines,
As levels in tilapia pose no threat of non-cancerous adverse health effects in children and adults. As is a known human carcinogen,
however, and U.S.EPA cancer risk assessment procedures indicate that a weekly consumption of 540 g (19 oz) or more for 70 years
would increase the upper bound cancer risk by 1 in 100,000 consumers exposed. Average current Se concentration was 2.2 μg g−1 ww in tilapia whole body samples and 1.9 μg g−1 ww in fillet (8.3 and 9 μg g−1 dw, respectively). Consumption of Se-contaminated tilapia was found to present no unacceptable risk for adverse health effects
for adults consuming up to 1000 g (35 oz) of fillet per week even when additional intakes of Se from other food items were
taken into account. Similarly, children weighing 30 kg or more could safely eat up to 430 g (15 oz) of tilapia fillet on a
weekly basis. A health advisory issued by the State of California in 1986 recommended, on the basis of Se levels, that consumption
of any fish from the Salton Sea be limited to 114 g (4 oz) every 2 weeks, but the rationale and calculations on which that
advisory was based are unavailable. We suggest that the existing health advisory for Salton Sea tilapia be revised by the
state in light of this new information and updated risk parameters for As and Se. Dichlorodiphenyltrichloroethane (DDE) was
detected in all samples of tilapia, with current levels averaging 0.085 μg g−1 in whole tilapia and 0.032 μg g−1 in fillet ww. Compared to screening values proposed by the U.S. EPA, these concentrations are unlikely to cause non-cancerous
health effects in anglers, but one might exceed a 1 × 10−5 increase in cancer risk by consuming more than 4 meals of tilapia per week. Similarly, polychlorinated biphenyls (PCBs) were
detected in tilapia fillets at levels that may increase the cancer risk for those anglers also eating more than 4 meals of
tilapia per week. These determinations are based, however, on DDE concentrations reported from a small sample size (n = 4), and on screening values recommended by U.S.EPA. The paucity of DDE and total DDT analyses carried out in recent times
on the edible portion of Salton Sea tilapia warrants additional analyses in order to evaluate the need for issuance of a fish
consumption advisory with regards to long term exposure to total DDT via consumption of Salton Sea fish. With regards to the
potential impact on fish and piscivorous birds, we cannot conclude whether concentrations of As in tilapia could pose a threat
to the fish and the birds feeding on them. Se concentrations, however, may be elevated enough to negatively affect fish health,
and reproduction and immune systems of piscivorous birds, but definitive studies are lacking. Total DDT and PCB concentrations
in whole tilapia are not elevated enough to have adverse effects on fish and piscivorous birds. Fish harvesting for fish meal
production has been proposed for the Salton Sea. Based on whole fish dry weight values of 61% protein and 21% ash, and the
determined contaminant levels, tilapia could yield a meal of reasonable quality for use in formulating poultry, livestock
and aquaculture feeds.
Guest Editor: John M. Melack
Saline Waters and their Biota 相似文献
9.
Animal models provide myriad benefits to both experimental and clinical research. Unfortunately, in many situations, they fall short of expected results or provide contradictory results. In part, this can be the result of traditional molecular biological approaches that are relatively inefficient in elucidating underlying molecular mechanism. To improve the efficacy of animal models, a technological breakthrough is required. The growing availability and application of the high-throughput methods make systematic comparisons between human and animal models easier to perform. In the present study, we introduce the concept of the comparative systems biology, which we define as "comparisons of biological systems in different states or species used to achieve an integrated understanding of life forms with all their characteristic complexity of interactions at multiple levels". Furthermore, we discuss the applications of RNA-seq and ChIP-seq technologies to comparative systems biology between human and animal models and assess the potential applications for this approach in the future studies. 相似文献
10.
Irene Rosa Eloisa Romano Bianca Saveria Fioretto Marco Matucci-Cerinic Mirko Manetti 《World journal of stem cells》2021,13(1):30-48
Adipose-derived stem cells(ADSCs)residing in the stromal vascular fraction(SVF)of white adipose tissue are recently emerging as an alternative tool for stem cell-based therapy in systemic sclerosis(SSc),a complex connective tissue disorder affecting the skin and internal organs with fibrotic and vascular lesions.Several preclinical and clinical studies have reported promising therapeutic effects of fat grafting and autologous SVF/ADSC-based local treatment for facial and hand cutaneous manifestations of SSc patients.However,currently available data indicate that ADSCs may represent a double-edged sword in SSc,as they may exhibit a pro-fibrotic and anti-adipogenic phenotype,possibly behaving as an additional pathogenic source of pro-fibrotic myofibroblasts through the adipocyte-to-myofibroblast transition process.Thus,in the perspective of a larger employ of SSc-ADSCs for further therapeutic applications,it is important to definitely unravel whether these cells present a comparable phenotype and similar immunosuppressive,anti-inflammatory,anti-fibrotic and pro-angiogenic properties in respect to healthy ADSCs.In light of the dual role that ADSCs seem to play in SSc,this review will provide a summary of the most recent insights into the preclinical and clinical studies employing SVF and ADSCs for the treatment of the disease and,at the same time,will focus on the main findings highlighting the possible involvement of these stem cells in SSc-related fibrosis pathogenesis. 相似文献
11.
This paper reports the design methodology and control strategy in the development of a novel hexapod robot HITCR-II that is suitable for walking on unstructured terrain. First, the entire sensor system is designed to equip the robot with the perception of external environment and its internal states. The structure parameters are optimized for improving the dexterity of the robot. Second, a foot-force distribution model and a compensation model are built to achieve posture control. The two models are capable of effectively improving the stability of hexapod walking on unstructured terrain. Finally, the Posture Control strategy based on Force Distribution and Compensation (PCFDC) is applied to the HITCR-II hexapod robot. The experimental results show that the robot can effectively restrain the vibration of trunk and keep stable while walking and crossing over the un- structured terrains. 相似文献
12.
This paper describes a portable chamber that measures net primary production of stream periphyton using a 14C uptake method. The unique feature is that substrates are moved through water at a velocity of 20 cm s −1 rather than moving water over substrates. The chamber consists of a plexiglass cylinder that is 9 cm in height and 15 cm
in diameter. On the top of the cylinder is a DC gearmotor powered by a 12 volt, deep cycle, marine battery. The motor turns
a shaft that rotates a 13.3 cm plexiglass plate at a velocity of 20 cm s −1 . Small tiles (3.2 cm × 3.2 cm × 0.5 cm) that have natural algal assemblages are mounted on the rotating plate. After adding
500 ml of filtered stream water and 185 kBq (5 μCi) NaH14CO3 to the chamber, the chambers are placed along a stream margin for 5 h. Measurements of 14C uptake by algae on the tiles provide estimates of net primary production (NPP). To assess the sensitivity and practicality
of the chamber, algal primary production was measured in open and closed canopy sections of Kingsley Creek, Randallsville,
New York. In autumn, primary production was higher in the open than closed canopy section and NPP was lower in spring in both
sections probably because of scouring of algae due to snowmelt. 相似文献
13.
E. K. Garger V. Kashpur G. Belov V. Demchuk J. Tschiersch F. Wagenpfeil H. G. Paretzke F. Besnus W. Holländer J. Martinez-Serrano I. Vintersved 《Radiation and environmental biophysics》1997,36(3):139-148
Results of measurements of the resuspended radioactive aerosols in the Chernobyl area are presented which were obtained soon
after the Chernobyl reactor accident and in a European project in 1992–1993. The measurements were carried out with the intention
of obtaining a data base for dose assessment of resuspended radioactive particles. Potential significant dose contributions
may result from inhalation and secondary contamination due to resuspended radionuclides. In this first article of a series
of three papers, the instrumentation and the measurement uncertainties are discussed. An effort was made to sample quantitatively
giant aerosol particles (particles larger than 10 μm aerodynamic diameter) as well. The comparison of the samplers shows,
in general, an agreement of concentration measurements of 137Cs and 7Be within a factor of two. One sampler was identified with larger discrepancies and needs additional investigation of its
sampling characteristics; for another device, the recalibration of the analysing system is recommended. Ordinary integrating
samplers have a loss of about 30% in 137Cs activity compared to an isokinetic sampler collecting giant particles as well. The mean ratio of 137Cs activity concentration between an instrument sampling only particles larger than 10 μm and an ordinary integrating sampler
is 0.39 ± 0.15 during anthropogenic-enhanced resuspension. These findings demonstrate the significant contribution of giant
particles to resuspended airborne radioactivity. The results of this study concerning integral measurements during wind-driven
resuspension proved to be in good agreement with previously published data on resuspension.
Received: 15 May 1997 / Accepted: 4 August 1997 相似文献
14.
Epigenetic changes in virus-associated human cancers 总被引:6,自引:0,他引:6
Epigenetics of human cancer becomes an area of emerging research direction due to a growing understanding of specific epigenetic pathways and rapid development of detection technologies. Aberrant promoter hypermethylation is a prevalent phenonmena in human cancers. Tumor suppressor genes are often hypermethylated due to the increased activity or deregulation of DNMTs. Increasing evidence also reveals that viral genes are one of the key players in regulating DNA methylation. In this review, we will focus on hypermethylation and tumor suppressor gene silencing and the signal pathways that are involved, particularly in cancers closely associated with the hepatitis B virus, simian virus 40 (SV40), and Epstein-Barr virus. In addition, we will discuss current technologies for genome-wide detection of epigenetically regulated targets, which allow for systematic DNA hypermethylation analysis. The study of epigenetic changes should provide a global view of gene profile in cancer, and epigenetic markers could be used for early detection, prognosis, and therapy of cancer. 相似文献
15.
16.
Pluripotent cellular models have shown great promise in the study of a number of neurological disorders.Several advantages of using a stem cell model include the potential for cells to derive disease relevant neuronal cell types,providing a system for researchers to monitor disease progression during neurogenesis,along with serving as a platform for drug discovery.A number of stem cell derived models have been employed to establish in vitro research models of Huntington’s disease that can be used to investigate cellular pathology and screen for drug and cell-based therapies.Although some progress has been made,there are a number of challenges and limitations that must be overcome before the true potential of this research strategy is achieved.In this article we review current stem cell models that have been reported,as well as discuss the issues that impair these studies.We also highlight the prospective application of Huntington’s disease stem cell models in the development of novel therapeutic strategies and advancement of personalized medicine. 相似文献
17.
Chamaegigas intrepidus Dinter is a poikilohydric aquatic plant that lives in rock pools on granite outcrops in central Namibia. The pools are filled
with water only intermittently during the wet season, and the plants may pass through up to 20 rehydration/dehydration cycles
during the summer rains. The potential nitrogen sources for the rehydrated plants are ammonium, which is only present at 10–20
μm, amino acids, particularly glycine, and urea, which is generally present at 20–30 μm. We show that urea can be utilised by plants in the field through the presence of urease in the sediments of the rock pools.
Urease activity is higher in non-submerged than in submerged sediments, and it can survive 6 months of complete dryness at
temperatures up to 60°C. Experiments with [14C]urea under laboratory conditions show that the roots of C. intrepidus are unable to take up urea; while 15N-nuclear magnetic resonance experiments show that [15N]urea is only metabolised to labelled glutamine and glutamate after ammonium has been released by the action of urease. Thus
urease plays a vital role in allowing urea to be utilised as a major N source in this nutrient-limited aquatic ecosystem.
Received: 23 April 1999 / Accepted: 8 November 1999 相似文献
18.
Biological effects of ion beams in Nicotiana tabacum L. 总被引:2,自引:0,他引:2
Yoshihiro Hase Kazuhiko Shimono Masayoshi Inoue Atsushi Tanaka Hiroshi Watanabe 《Radiation and environmental biophysics》1999,38(2):111-115
The biological effects of ion beams on Nicotiana tabacum L., particularly the induction of chromosome aberrations, were investigated. Dry seeds were exposed to 12C5+, 4He2+ and 1H+ beams with linear energy transfer (LET) ranging from 1 to 111 keV/μm and irradiated with gamma-rays. Ion beams were more
effective in reducing germination and survival of the seeds than gamma-rays. The LD50 for 12C5+ beams, 4He2+ beams and gamma-rays were 35, 60 and 500 Gy, respectively. The frequencies of mitotic cells with chromosome aberrations,
such as chromosome bridges, acentric fragments and lagging chromosomes in the root tip cells of the exposed seeds, increased
linearly with increasing doses. Relative biological effectiveness (RBE) values, based on the doses that induced a survival
inhibition of 50% and a 10% frequency of aberrant cells, were 14.3–17.5 for the 12C5+ beams, 7.0–8.3 for the 4He2+ beams and 7.8 for the 1H+ beams. Furthermore, the relative ratios of the chromosome aberration types were significantly different between the ion beam
and the gamma-ray regimes: chromosome fragments were more frequent in the former, and chromosome bridges in the latter. Based
on these results, we concluded that the repair process of initial lesions induced by ion beams may be different from that
induced by low- LET radiation.
Received: 29 October 1998 / Accepted in revised form: 25 March 1999 相似文献
19.
Mini-review to analyse the phenotype, genotype, and alloantibody titre against Diego antigens in the Chinese population
下载免费PDF全文
![点击此处可从《Asia-Pacific Journal of Blood Types and Genes》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Na M Zhiyuan Xu Yushiang Lin Haochun Chang Xiaofei Li Daowang Fan Yan Qiu Tianhong Miao 《Asia-Pacific Journal of Blood Types and Genes》2017,1(4):55-60
Diego blood antigens are important antigens in Mongoloid people and native South Americans owing to the Dia positivity rate found in these populations. However, the prevalence of Dia+ is different among native populations of America and China. Our study reviewed the genotype, phenotype, and alloantibody titre of Diego blood group antigens to explain the existence of the dosage effect for Diego antigens. The prevalence of Dia+ varied from 2.26% to 10.43% in the Chinese population was lower than that observed in Native Americans living in USA, Brazil, and Venezuela. The Di(a+b-)/Di(a+b+) ratio in the Chinese was 0.0044~0.0268, which was also lower than that observed in native Americans at 0.0203–0.1628, indicating that the major allele was Di(a+b+) in Dia+Chinese or Asians. We also collected Di(a+b-), Di(a+b+), and Di(a-b+) samples from Chinese samples to examine the agglutinin titres with anti-Dia and anti-Dib and the results supported the existence of the dosage effect for Diego antigens. The agglutinin titres of anti-Dia in Di(a+b+) specimens were lower than those in Di(a+b-) specimens, and agglutinin titres of anti-Dib in Di(a+b+) specimens were lower than those in Di(a-b+) specimens. Alloantibodies against Dia and Dib antigen are majorly responsible for haemolytic disease of the new-born and anti-Dia reactions resulting in stillborn foetus and transfusion reactions, such as fever and rash,were also reported in the Chinese population. 相似文献
20.
王利松 《植物分类与资源学报》2011,33(1):69-74
Biodiversity research increasingly relies on distribution networks for dealing with large-scale primary data.Up-to-date information on biodiversity is critical for the proper management and conservation of any area.The first step towards conservation should be to compile an authoritative species inventory or checklist.Catalogue of Life:Higher Plants in China(CNPC) is an ongoing biodiversity informatics project with the aim to integrate existing higher plants inventory data,and provide access via an internet based web service to public user and the scientific community.The CNPC,for the first time,provides integrated and authoritative taxonomic information on higher plant species found in China,and this database will be permanent,free and continously updated.Presently,a total of 34 377 species have been included in the database.Among of them,16 620 species are only found in China.Taxa are classified into 432 families and 3 941 genera.The CNPC will be an important source for scientists working on Chinese flora,and will play an important role in helping to achieve the targets set under the Global Strategy for Plant Conservation in the future. 相似文献