The accumulation of^(222)Rn and^(220)Rn progeny in poorly ventilated environments poses the risk of natural radiation exposure to the public.A previous study indicated that satisfactory results in determining the^(222...The accumulation of^(222)Rn and^(220)Rn progeny in poorly ventilated environments poses the risk of natural radiation exposure to the public.A previous study indicated that satisfactory results in determining the^(222)Rn and^(220)Rn progeny concentrations by measuring the total alpha counts at five time intervals within 560 min should be expected only in the case of high progeny concentrations in air.To complete the measurement within a relatively short period and adapt it for simultaneous measurements at comparatively lower^(222)Rn and^(220)Rn progeny concentrations,a novel mathematical model was proposed based on the radioactive decay law.This model employs a nonlinear fitting method to distinguish nuclides with overlapping spectra by utilizing the alpha particle counts of non-overlapping spectra within consecutive measurement cycles to obtain the concentrations of^(222)Rn and^(220)Rn progeny in air.Several verification experiments were conducted using an alpha spectrometer.The experimental results demonstrate that the concentrations of^(222)Rn and^(220)Rn progeny calculated by the new method align more closely with the actual circumstances than those calculated by the total count method,and their relative uncertainties are all within±16%.Furthermore,the measurement time was reduced to 90 min,representing an acceleration of 84%.The improved capability of the new method in distinguishing alpha particles with similar energies emitted from ^(218)Po and^(212)Bi,both approximately 6 MeV,contributed to realizing more accurate results.The proposed method has the potential advantage of measuring relatively low concentrations of^(222)Rn and^(220)Rn progeny in air more quickly via air filtration.展开更多
为了明确肉质相关基因氟烷基因(Hal)、酸肉基因(RN)和脂肪肥胖相关基因(FTO)在国内外不同猪种群体间的遗传变异特性,本研究以大约克、长白、杜洛克和金华猪等猪种群体为研究对象,应用PCR-RFLP技术分别检测了Hal、RN和FTO基因的多态性,...为了明确肉质相关基因氟烷基因(Hal)、酸肉基因(RN)和脂肪肥胖相关基因(FTO)在国内外不同猪种群体间的遗传变异特性,本研究以大约克、长白、杜洛克和金华猪等猪种群体为研究对象,应用PCR-RFLP技术分别检测了Hal、RN和FTO基因的多态性,并分析了FTO基因上2个多态位点g.276G>T和c.594C>G的遗传变异情况。结果表明:(1)在杜洛克猪中发现了Hal的基因型Hal NHal n,其频率为0.166,但未发现基因型Hal n Hal n,其它猪种群体中仅检测到了基因型Hal NHal N;(2)在已检测的所有猪种群体中只检测到RN基因的rn/rn基因型,未发现rn/RN和RN/RN基因型;(3)在FTO的g.276G>T位点上,金华猪呈现单态,其它猪种群体均呈现多态。在FTO的c.594C>G位点上,4个猪种群体均呈现多态,3个外来猪种群体均以CC基因型频率较高,而金华猪则以GG基因型频率较高。研究结果提示,由于Hal基因在养猪生产中的利弊双重性,因此在某些猪种群体中仍然存在较高频率的Hal NHal n基因型。此外,结合FTO基因的生理功能和已有的研究结果,可在特定的猪群中将其作为影响猪肉质性状的候选基因。本研究发现FTO的基因型分布在我国优良地方猪种金华猪与国外3个种猪群间存在较大差异,为深入研究不同品种猪的肉质形成机理提供了基础数据。展开更多
基金supported by the National Natural Science Foundation of China(No.12075112)Natural Science Foundation of Hunan(No.2023JJ50121),Natural Science Foundation of Hunan Province(No.2023JJ50091)Key Projects of Hunan Provincial Department of Education(No.23A0516).
文摘The accumulation of^(222)Rn and^(220)Rn progeny in poorly ventilated environments poses the risk of natural radiation exposure to the public.A previous study indicated that satisfactory results in determining the^(222)Rn and^(220)Rn progeny concentrations by measuring the total alpha counts at five time intervals within 560 min should be expected only in the case of high progeny concentrations in air.To complete the measurement within a relatively short period and adapt it for simultaneous measurements at comparatively lower^(222)Rn and^(220)Rn progeny concentrations,a novel mathematical model was proposed based on the radioactive decay law.This model employs a nonlinear fitting method to distinguish nuclides with overlapping spectra by utilizing the alpha particle counts of non-overlapping spectra within consecutive measurement cycles to obtain the concentrations of^(222)Rn and^(220)Rn progeny in air.Several verification experiments were conducted using an alpha spectrometer.The experimental results demonstrate that the concentrations of^(222)Rn and^(220)Rn progeny calculated by the new method align more closely with the actual circumstances than those calculated by the total count method,and their relative uncertainties are all within±16%.Furthermore,the measurement time was reduced to 90 min,representing an acceleration of 84%.The improved capability of the new method in distinguishing alpha particles with similar energies emitted from ^(218)Po and^(212)Bi,both approximately 6 MeV,contributed to realizing more accurate results.The proposed method has the potential advantage of measuring relatively low concentrations of^(222)Rn and^(220)Rn progeny in air more quickly via air filtration.
文摘为了明确肉质相关基因氟烷基因(Hal)、酸肉基因(RN)和脂肪肥胖相关基因(FTO)在国内外不同猪种群体间的遗传变异特性,本研究以大约克、长白、杜洛克和金华猪等猪种群体为研究对象,应用PCR-RFLP技术分别检测了Hal、RN和FTO基因的多态性,并分析了FTO基因上2个多态位点g.276G>T和c.594C>G的遗传变异情况。结果表明:(1)在杜洛克猪中发现了Hal的基因型Hal NHal n,其频率为0.166,但未发现基因型Hal n Hal n,其它猪种群体中仅检测到了基因型Hal NHal N;(2)在已检测的所有猪种群体中只检测到RN基因的rn/rn基因型,未发现rn/RN和RN/RN基因型;(3)在FTO的g.276G>T位点上,金华猪呈现单态,其它猪种群体均呈现多态。在FTO的c.594C>G位点上,4个猪种群体均呈现多态,3个外来猪种群体均以CC基因型频率较高,而金华猪则以GG基因型频率较高。研究结果提示,由于Hal基因在养猪生产中的利弊双重性,因此在某些猪种群体中仍然存在较高频率的Hal NHal n基因型。此外,结合FTO基因的生理功能和已有的研究结果,可在特定的猪群中将其作为影响猪肉质性状的候选基因。本研究发现FTO的基因型分布在我国优良地方猪种金华猪与国外3个种猪群间存在较大差异,为深入研究不同品种猪的肉质形成机理提供了基础数据。
