利用螺旋藻富集碘的实验

本文研究了碘化钾 (KI)对极大螺旋藻 (Spirulinamaxima)生长的影响以及碘在细胞中的富集作用 .结果表明 :在 0～ 40 0mg/dm3范围内 ,KI对螺旋藻的生长没有明显的抑制作用 ,在较低的含量内甚至有一定的促进作用 .极大螺旋藻的最高KI耐受范围在 40 0 0～ 50 0 0mg/dm3之间 .螺旋藻细胞中的碘含量与培养液中外加的KI含量有一定的关系 ,在KI添加含量为 90 0mg/dm3时 ,螺旋藻的收获量 (2 77.1 7mg/dm3)比对照组 (1 0 4.47mg/dm3)增加 1 65%,藻细胞碘含量[0 .3 3 1× 1 0 -2 (m/m) ]比对照组 [0 .0 2 5× 1 0 -2 (m/m) ]增加约 1 2倍 .     

Molecular iodine reduction by natural and model organic substances in seawater

The reactivity of 2 µM molecular iodine in seawater toward various organic compounds containing aromatic, -keto, amino, olefinic and sugar functional groups was investigated. More detailed studies have been made of the reduction kinetics with salicylic acid, -ketoglutaric acid and the polypeptide oxidized glutathione, particularly to establish whether variation over the pH range 4–9 would provide a similar reduction reactivity or fingerprint to that of molecular iodine added to natural seawater. The data indicates that compounds with only one functional group react with first order kinetics whereas compounds with multiple functional groups show more complex behaviour. Kinetic and thermodynamic modelling indicates that HOI is the main iodine species reacting with organic matter at seawater pH of 8.2. Based on the pH fingerprints, peptides and compounds containing carbonyl or -keto groups are the key reductants of molecular iodine added to seawater. These compounds form C-I and N-I bonds which can allow for a rich organic iodine chemistry in seawater. The model compound results are discussed in relation to oceanic processes.     

Efficiency of Moso Bamboo Charcoal and Activated Carbon for Adsorbing Radioactive Iodine

Preventing radioactive pollution is a troublesome problem but an urgent concern worldwide because radioactive substances cause serious health‐related hazards to human being. The adsorption method has been used for many years to concentrate and remove radioactive pollutants; selecting an adequate adsorbent is the key to the success of an adsorption‐based pollution abatement system. In Taiwan, all nuclear power plants use activated carbon as the adsorbent to treat radiation‐contaminated air emission. The activated carbon is entirely imported; its price and manufacturing technology are entirely controlled by international companies. Taiwan is rich in bamboo, which is one of the raw materials for high‐quality activated carbon. Thus, a less costly activated carbon with the same or even better adsorptive capability as the imported adsorbent can be made from bamboo. The objective of this research is to confirm the adsorptive characteristics and efficiency of the activated carbon made of Taiwan native bamboo for removing ¹³¹I gas from air in the laboratory. The study was conducted using new activated carbon module assembled for treating ¹³¹I‐contaminated air. The laboratory results reveal that the ¹³¹I removal efficiency for a single‐pass module is as high as 70%, and the overall efficiency is 100% for four single‐pass modules operated in series. The bamboo charcoal and bamboo activated carbon have suitable functional groups for adsorbing ¹³¹I and they have greater adsorption capacities than commercial activated carbons. Main mechanism is for trapping of radioiodine on impregnated charcoal, as a result of surface oxidation. When volatile radioiodine is trapped by potassium iodide‐impregnated bamboo charcoal, the iodo‐compound is first adsorbed on the charcoal surface, and then migrates to iodide ion sites where isotope exchange occurs.     

共振光猝灭法测定环境水样中痕量硒

在阿拉伯树胶(AG)存在下,0.14 mol/L硫酸介质中,硒(Ⅳ)与过量的I-反应生成I3-,加入乙酸钠后I3-与亚甲基蓝反应成离子缔合物,在波长288 nm处共振光猝灭,建立了共振光散射法测定痕量硒的方法.确定了碘化钾、亚甲基蓝、乙酸钠和增溶剂阿拉伯树胶溶液的浓度,在室温(20～30℃)下反应15 min,提高了体...     

“双低”技术应用于 CTPA 的可行性研究?

目的：评估“双低”（低管电压与低碘量）技术在肺动脉 CT 血管成像（CTPA）中的图像质量、辐射剂量及临床价值。方法：前瞻性将临床疑似肺动脉栓塞（PAE）患者105例,随机分为 A、B、C 三组行 CTPA 检查（n =35）。A 组：管电压120 kVp、对比剂40mL（碘浓度350 mgI/m）、注射速率4 mL/s;B 组：管电压100 kVp、对比剂35 mL（碘浓度300 mgI/m）、注射速率3.5 mL/s;C 组：管电压80 kVp、对比剂30 mL（碘浓度270 mgI/m）、注射速率3 mL/s。三组均开启管电流调制(ATCM)技术,A 组采用滤波反投影算法（FBP）,B、C 两组采用 ASIR 技术重建。记录每例患者的对比剂量、CT 容积剂量指数（CTDIvol）、剂量长度乘积（DLP）,并计算有效剂量（ED）。在轴位图像测量肺动脉干、左、右肺动脉及亚段肺动脉的 CT 值。采用 Kruskal-Wallis H 检验来比较3组的辐射剂量、碘量、图像质量的主观及客观评价等指标。结果：A、B、C 三组分别在肺动脉干、左、右肺动脉及亚段肺动脉的 CT 值差异均无统计学意义（P >0.05）;三组图像背景噪声、SNR、CNR 及主观评价差异亦均无统计学意义（P >0.05）;与 A 组相比,B 组和 C 组的 ED 分别降低了38.09％、51.99％;A 组接受碘量分别高于 B 组25％和 C 组42.14％。结论：管电压80 kVp、对比剂30 mL(碘浓度270 mgI/mL)、注射速率3 mL/s 在肺动脉 CTA 中的应用是可行的,图像质量既满足诊断,又降低辐射剂量和碘量。     

HPLC-ICP-MS法研究内蒙古锡盟和新疆塔城高碘地区地下水的总碘及碘形态特征

长期饮用高碘水将对人体造成危害,地下水总碘及碘形态分析对于高碘地区碘环境地球化学研究具有重要价值。本文采用高效液相色谱-电感耦合等离子体质谱联用技术对内蒙古锡盟与新疆塔城高碘地区地下水总碘及碘形态进行测定。研究表明:锡盟地区地下水中碘以I-形态为主,总碘量维持在200μg/L,个别点位达到600μg/L甚至1700μg/L,呈环状分布,从东北至西南呈现"低-高-低"的分布规律;塔城地区地下水中的碘以IO-3形态为主,总碘量不足100μg/L,个别点位接近200μg/L,呈层状分布,自东向西逐渐升高。分析认为,氧化性的条件利于不同碘形态之间的转化;溶解氧过高或过低都不利于碘的储存;碘会随着可溶性盐的流失而流失;沿河流的流向,下游地势较低,总碘得到积累。本研究结果对于锡盟和塔城地区科学预防甲状腺肿、制定法律法规具有指导作用。     

Latitudinal distribution of iodine in sediments in the Chukchi Sea and the Bering Sea

Iodine is a trace element playing an important role in vital activities of organisms. It is im-portant for human bodys thyroid gland. Deficient or excessive iodine will not only influence hu-man health but also cause feeblemindedness, so great attention h…     

水源中同位素氘对动植物的影响

通过水中氘同位素组成的分析，研究水中氘对生物生长的影响，认为淡水中氘亏损程度较高的水能提高生物的机能活性，促进生物体的新陈代谢。在甲状腺病变多发区中，导致碘缺乏症的主要因素并不是水中碘含量低，而是与水中氘亏损程度高有关，实验表明，氘亏损程度高的淡水还能的淡水还能激发植物种子的萌芽，提高萌芽率，从而增加农作物产量。     

Remobilization of Iodine in Marine Sediments During Early Diagenesis

Based on the sedimentary geochemical studies of the Antarctic Ocean and the various geochemical parameters available,this paper deals with the process of emobilization of iodine in marine sediments during early diagenesis.The results showed that the process is not always controlled completely by organic matter as was expected previously.On average the adsorption and oxide phases of iodine account respectively for 23% and 32% of the total in continental-shelf and hemipelagic surficial sediments.Chemical analysis has revealed that the upward diffusion flux and redox conditions would play an important role in the concentration of iodine in the surface sediments.And the species of iodine in the surfial sediments characteristic of high I/Corg ratios would bepredominated by the oxide and adsorption phases.As experimentally evidenced,it is the early diagenetic remoibilization of iodine associated with the oxide and adsorption phases that led to the decrease of I/Corg with increasing depth.Calculations suggested that the diffusion flux of iodine from the deep parts of te sedimentary columum upwards is on the same order of magnitude as the deposition flux of it from sea water.This may be one of the important factors leading to the depletion of iodine in sedimentary rocks.On the basis of the above discussion and calculations the author has proposed a model for the remobilization of iodine in marine sediments during early diagenesis.     

海藻中碘的化学种态研究Ⅰ

用化学分离结合中子活化法研究了海带、网翼藻、海黍子、松藻、石莼、礁膜和江篱7种海藻中总碘及水溶性碘、有机碘、I-和IO₃-等不同形态碘的分布.研究结果表明:不同海藻中碘及其化学种态差别较大,海带中碘含量最高,达734×106(湿重),且99.2%的碘为水溶性碘.其他几种海藻中碘含量较低,且水溶性碘仅占16.5%～40.8%.海藻浸出液中碘主要以I-的形式存在,占浸出总碘量的61.0%～92.7%,其次为有机碘占5.5%～37.4%,IO₃-含量最少,仅占1.4%～4.5%.该研究结果提示不同海藻的富碘机制可能不尽相同.从食用的角度看,其中碘的生物利用度也可能有较大的差异.