A beta spectrometric method for the rapid determination of strontium-90 （90Sr） in water samples was developed and tested. 90Sr is extracted directly from the water samples by means of a scintillator cocktail, contai...A beta spectrometric method for the rapid determination of strontium-90 （90Sr） in water samples was developed and tested. 90Sr is extracted directly from the water samples by means of a scintillator cocktail, containing the crown ether dicyclohexano-18-crown-6 as an extracting agent （STRONEX）. Minimal clean-up is necessary when other beta nuclides are present, such as barium-140. These nuclides are eliminated by a barium chromate scavenge, prior to the extraction step. The method presented here allows for the investigation of at least 12 water samples a day and is therefore a suitable tool for emergency analysis.展开更多
Light weight radioisotope (LWR) 89Sr and 90Sr could be obtained from used rods in fission atomic plants. The economics of the disposal of nuclear bars indicate the convenience to develop added value applications. The ...Light weight radioisotope (LWR) 89Sr and 90Sr could be obtained from used rods in fission atomic plants. The economics of the disposal of nuclear bars indicate the convenience to develop added value applications. The difference in t1/2 allows 89Sr to deliver its energy at a rate 200 times higher than 90Sr. A large emission number of low penetrating power particles in a short time characterize 89Sr, which allows that these highly radioactive LWR involves a rather limited danger. Chemical similitude of calcium and strontium uptake has led to the use of 89Sr in treatment of bone cancer metastasis. 89Sr damages animal tissues because ionize water, but penetrates through the skin about: 5 to 8 mm. Hence, to obtain it in insoluble form, like obtaining 89Sr silicate, could make possible its wider use. Purifying 89Sr from contaminant 90Sr allows that after one year do not leave any contamination. LWR could be covered with scintillators substances, which by subtracting kinetic energy from beta-radiation, emit light and function as a major source of shielding. This treatment engineers Radioisotope Light Generators (RLG). Their light could activate photovoltaic cells (PV), which could lead to nano-devices without moving parts RLG-PV.展开更多
AIM: To evaluate the risk factors leading to recurrence in patients with ocular surface squamous neoplasia(OSSN)METHODS: The records of 112 patients with OSSN who underwent treatment and follow-up between February 199...AIM: To evaluate the risk factors leading to recurrence in patients with ocular surface squamous neoplasia(OSSN)METHODS: The records of 112 patients with OSSN who underwent treatment and follow-up between February 1999 and August 2018 were reviewed retrospectively.RESULTS: Totally 67 patients(59.8%) were male and 45 patients(40.2%) were female. The mean age at presentation was 63.7 y(range 22-87 y). Partial lamellar scleroconjunctivectomy(PLSC) was performed in 105(93.7%) cases and enucleation was performed in 7(6.3%) cases due to bulbus invasion as the first step treatment. Treatments used in addition to PLSC included cryotherapy in 78 eyes(74.3%), alcohol epitheliectomy in 57 eyes(54.3%) for presence of corneal involvement, and amniotic membrane transplantation in 17 eyes(16.2%) for ocular surface reconstruction. Topical mitomycin C was used in 10 patients(9.5%) and strontium-90(Str-90) treatment in 4(3.8%) patients because surgical margins were tumor positive at the histopathological examination. Postoperative histopathologic diagnoses were squamous cell carcinoma(52 cases), carcinoma in situ(44 cases), moderate conjunctival intraepithelial neoplasia(11 cases), and mild conjunctiva intraepithelial neoplasia(5 cases). At a mean follow-up of 20.1 mo, tumor recurrence was observed in 21(18.8%) cases. The rate of recurrence was found to be lower in cases that underwent supplemental cryotherapy compared to those that did not(P<0.001). There was no metastasis in any case. CONCLUSION: In our series, the recurrence rate is 18.8% and overall globe salvage rate is 90.2% for OSSN at relatively short-term follow-up.展开更多
Objective:To explore the separation condition for 90Sr using crown ether resin,in order to establish a fast method for analysis of 90Sr in food and environmental samples.Methods:Stable strontium isotope(88Sr)was used ...Objective:To explore the separation condition for 90Sr using crown ether resin,in order to establish a fast method for analysis of 90Sr in food and environmental samples.Methods:Stable strontium isotope(88Sr)was used to simulate the radioactive 90Sr,and the concentration of 88Sr in elution solution was detected using inductively coupled plasma mass spectrometry(ICP–MS).The separation conditions were investigated through batch experiment.Results:Under the optimized experimental conditions,the maximum adsorption capacity of crown ether resin was 22.28 mg/g.4.0–8.0 mol/L nitric acid made it easier for the Sr2þto load on the resin,and 20 mL ultrapure water was used to rinse the chromatographic column to achieve a good separation effect,by which the recoveries of Sr2þwere nearly close to 100%.The average recovery rates of 4 samples were 60.25%,69.26%,75.09%and 66.33%,respectively.Conclusions:Crown ether resin has very good selectivity and adsorption for 90Sr.The optimized conditions were high-efficiency and easy to operate.The separation method has great potential for the fast analysis of 90Sr in food and environmental samples.展开更多
文摘A beta spectrometric method for the rapid determination of strontium-90 （90Sr） in water samples was developed and tested. 90Sr is extracted directly from the water samples by means of a scintillator cocktail, containing the crown ether dicyclohexano-18-crown-6 as an extracting agent （STRONEX）. Minimal clean-up is necessary when other beta nuclides are present, such as barium-140. These nuclides are eliminated by a barium chromate scavenge, prior to the extraction step. The method presented here allows for the investigation of at least 12 water samples a day and is therefore a suitable tool for emergency analysis.
文摘Light weight radioisotope (LWR) 89Sr and 90Sr could be obtained from used rods in fission atomic plants. The economics of the disposal of nuclear bars indicate the convenience to develop added value applications. The difference in t1/2 allows 89Sr to deliver its energy at a rate 200 times higher than 90Sr. A large emission number of low penetrating power particles in a short time characterize 89Sr, which allows that these highly radioactive LWR involves a rather limited danger. Chemical similitude of calcium and strontium uptake has led to the use of 89Sr in treatment of bone cancer metastasis. 89Sr damages animal tissues because ionize water, but penetrates through the skin about: 5 to 8 mm. Hence, to obtain it in insoluble form, like obtaining 89Sr silicate, could make possible its wider use. Purifying 89Sr from contaminant 90Sr allows that after one year do not leave any contamination. LWR could be covered with scintillators substances, which by subtracting kinetic energy from beta-radiation, emit light and function as a major source of shielding. This treatment engineers Radioisotope Light Generators (RLG). Their light could activate photovoltaic cells (PV), which could lead to nano-devices without moving parts RLG-PV.
文摘AIM: To evaluate the risk factors leading to recurrence in patients with ocular surface squamous neoplasia(OSSN)METHODS: The records of 112 patients with OSSN who underwent treatment and follow-up between February 1999 and August 2018 were reviewed retrospectively.RESULTS: Totally 67 patients(59.8%) were male and 45 patients(40.2%) were female. The mean age at presentation was 63.7 y(range 22-87 y). Partial lamellar scleroconjunctivectomy(PLSC) was performed in 105(93.7%) cases and enucleation was performed in 7(6.3%) cases due to bulbus invasion as the first step treatment. Treatments used in addition to PLSC included cryotherapy in 78 eyes(74.3%), alcohol epitheliectomy in 57 eyes(54.3%) for presence of corneal involvement, and amniotic membrane transplantation in 17 eyes(16.2%) for ocular surface reconstruction. Topical mitomycin C was used in 10 patients(9.5%) and strontium-90(Str-90) treatment in 4(3.8%) patients because surgical margins were tumor positive at the histopathological examination. Postoperative histopathologic diagnoses were squamous cell carcinoma(52 cases), carcinoma in situ(44 cases), moderate conjunctival intraepithelial neoplasia(11 cases), and mild conjunctiva intraepithelial neoplasia(5 cases). At a mean follow-up of 20.1 mo, tumor recurrence was observed in 21(18.8%) cases. The rate of recurrence was found to be lower in cases that underwent supplemental cryotherapy compared to those that did not(P<0.001). There was no metastasis in any case. CONCLUSION: In our series, the recurrence rate is 18.8% and overall globe salvage rate is 90.2% for OSSN at relatively short-term follow-up.
基金This work was supported by the National Key Research and Development Program of China(No.2017YFC1601602)Environmental Radioactivity Research Network Center(ERAN I-21-18)+1 种基金Key Program of Tianjin Municipal Natural Science Foundation(No.19JCZDJC40500)Program of National Center for Occupational Safety and Health(No.2020010).
文摘Objective:To explore the separation condition for 90Sr using crown ether resin,in order to establish a fast method for analysis of 90Sr in food and environmental samples.Methods:Stable strontium isotope(88Sr)was used to simulate the radioactive 90Sr,and the concentration of 88Sr in elution solution was detected using inductively coupled plasma mass spectrometry(ICP–MS).The separation conditions were investigated through batch experiment.Results:Under the optimized experimental conditions,the maximum adsorption capacity of crown ether resin was 22.28 mg/g.4.0–8.0 mol/L nitric acid made it easier for the Sr2þto load on the resin,and 20 mL ultrapure water was used to rinse the chromatographic column to achieve a good separation effect,by which the recoveries of Sr2þwere nearly close to 100%.The average recovery rates of 4 samples were 60.25%,69.26%,75.09%and 66.33%,respectively.Conclusions:Crown ether resin has very good selectivity and adsorption for 90Sr.The optimized conditions were high-efficiency and easy to operate.The separation method has great potential for the fast analysis of 90Sr in food and environmental samples.
