硒锌氨基酸治疗儿童锌缺乏症疗效分析

为观察硒锌氨基酸治疗儿童锌缺乏的疗效,将98例锌缺乏儿童随机分为硒锌氨基酸治疗组及对照组,测定治疗前后血锌增加值,并比较治疗效果。结果表明,治疗组血锌平均增加值为(16.37±4.89)μmol/L,对照组为(12.39±5.01)μmol/L,P<0.01,差异有高度显著性;治疗组50例中,显效36例,有效10例,无效4例,对照组48例中显效24例,有效12例,无效12例,χ2=4.12,P<0.05,差异有显著性。可见硒锌氨基酸治疗儿童锌缺乏症取得显著疗效。     

水和氯化铵提取-电感耦合等离子体发射光谱(ICP-AES)法测定石灰性土壤中交换性钾钠钙镁

为了提高石灰性土壤中交换性钾钠钙镁的分析效率及分析准确度,本文创新性采用水和氯化铵对石灰性土壤进行处理,并采用振荡交换、离心分离的方式进行石灰盐清洗、钾钠钙镁离子交换提取,提取液直接在电感耦合等离子体发射光谱仪(ICP-AES)上测定。该方法交换性盐基钙、镁、钾、钠的检出限分别为0.01、0.009、0.004、0.012cmol/kg。用国家一级标准物质GBW07498-新疆棕漠土和新疆地区石灰性土壤进行验证,方法精密度均小于5%,回收率在97％~105%。方法适用于石灰性（碱性）土壤（特别是新疆土壤）样品中交换性钾、钠、钙、镁的分析测定。     

直接火焰原子吸收法测定石灰性土壤中有效态铜镉铅锌

土壤中有效态金属系指能被植物吸收的金属,它与植物及人体关系极为密切,对其进行监测在污染评价中很有意义。有效态金属常用浸提剂浸提后进行测定。浸提剂种类很多。近年来已有报导,将 DTPA 浸提剂用于碱性或石灰性土壤中有效态镉、铅、铜、锌的测定,其提取量与植物体中的量具有较好的相关性。本文以北京地区石灰性土壤为试样,试以 DTPA 为浸提剂,对浸提剂浓度、浸提时间、土水比及直接火焰原     

锌与健康

为探讨微量元素锌与人体健康的关系，从锌的食物来源及影响吸收利用因素、锌的生物学作用，锌含量及发锌值，锌缺乏的临床表现等方面进行了综述。     

石灰性土壤中有效态镉、铅、铜、锌的测定

石灰性土壤中有效态金属元素的测定,文献报导不多,对同时测定镉、铅、铜、锌四种元素,尚未见报导。本文以北京地区石灰性土壤为样品,用乙二胺四乙酸二钠(EDTA)为浸提剂,吡咯烷二硫代甲酸铁-甲基异丁酮(APDC-MIBK)为萃取剂,采用原子吸收法测定上述四种元素。由于采用了与通常不同的做法:(1)以土壤浸提液绘制工作曲线代替水溶液曲线;(2)萃取后在保留水相而不是弃去水相的条件下进行测定,因此操作简便,结果准确,灵敏度高。     

人体缺锌的原因与治疗

人体锌缺乏主要原因有：(一)摄取不足，食物中缺乏动物性蛋白质，或由于加工不当，使食物中锌含量降低；或因疾病妨碍了锌的吸收；(二)锌的过度丢失；(三)锌需要量急速增加，以至供不应求，如妊娠、哺乳或创伤恢复期等。(四)小儿异食癖多由于锌吸收减少所致。(五)引起锌缺乏的疾病：肠源性肢端皮炎及营养性侏儒症等。     

南昌市城区416名儿童锌缺乏状况调查

为了解南昌市城区儿童锌缺乏状况，采集手指尖末梢血20μL用石墨炉原子吸收分光光度法测定全血锌浓度。以血锌值5.00μg/mL为正常下限。结果表明，该儿童人群血锌值呈非正态分布，样本中位数为5.659μg/mL，四分位数间距为Q3－Q1＝1．927。416名2－8岁儿童中男240人，女176人。锌缺乏人数134人，锌缺乏患病率35．80％。不同性别间血锌值无显著差异，而不同年龄间血锌值有显著差异，但未表现出与年龄呈正相关关系。提示南昌市城区儿童锌缺乏的发生率较高，应引起人们足够的重视。     

我国主要土壤中稀土元素的含量和分布

我国主要土壤Ｌａ，Ｃｅ，Ｎｄ，Ｓｍ和Ｙ的平均含量分别为４３．７、８６．２、３５．８、８．２１．８μｇ／ｇ，稀土总量为２６４μｇ／ｇ。稀土元素在成土过程中产生不同程度的富集和淋溶，但其含量末表现有地带性差异。在６１个土样中可给态稀土的平均含量为２４．９μｇ／ｇ，有从南向北降低的趋势；其中低于１０μｇ／ｇ的中酸性土壤占酸性土壤样品总数的１７％，低于１０μｇ／ｇ的中性、石灰性土壤占中性和石灰性土壤样品总     

儿童锌缺乏症防治存在的问题与对策

人们对儿童锌缺乏症的认识不足、误诊误治、检测过程复杂、药品剂型单调是锌缺乏防治存在的问题。相应对策应考虑组织专业服务，建立防治网；加强普及锌缺乏防治知识；改进检测方法和开发多元化的锌制剂品种。     

在儿童生长发育中铅的危害与锌的作用

综述了在儿童生长发育中铅的危害与锌的作用。认为铅中毒和锌缺乏将严重影响儿童的生长发育。铅对儿童是以中枢神经系统损坏为主,中构神经毒性最普遍的表现形式是智力和行为的异常。锌被誉为“生命之花”,在人的机体内具有极其重要的生理和生化功能,缺锌儿童发育迟缓、智力差、免疫力低下、食欲不振等。而且,锌能够减少组织中铅的蓄积和铅毒性作用的影响,补锌能有效降低人体铅的含量。葡萄糖酸是唯一被列入非处方药（OTC）目录的理想的有机锌补充剂。     

Zinc Biofortification in Food Crops Could Alleviate the Zinc Malnutrition in Human Health

Micronutrient malnutrition is a global health issue and needs immediate attention. Over two billion people across the globe suffer from micronutrient malnutrition. The widespread zinc (Zn) deficiency in soils, poor zinc intake by humans in their diet, low bioavailability, and health consequences has led the research community to think of an economic as well as sustainable strategy for the alleviation of zinc deficiency. Strategies like fortification and diet supplements, though effective, are not economical and most people in low-income countries cannot afford them, and they are the most vulnerable to Zn deficiency. In this regard, the biofortification of staple food crops with Zn has been considered a useful strategy. An agronomic biofortification approach that uses crop fertilization with Zn-based fertilizers at the appropriate time to ensure grain Zn enrichment has been found to be cost-effective, easy to practice, and efficient. Genetic biofortification, though time-consuming, is also highly effective. Moreover, a Zn-rich genotype once developed can also be used for many years without any recurring cost. Hence, both agronomic and genetic biofortification can be a very useful tool in alleviating Zn deficiency.     

The enormity of the zinc deficiency problem and available solutions; an overview

The societal cost of micronutrient deficiency (MND) or the “hidden hunger” is in millions of dollars/year, reducing the GDP of some countries by as much as 11%. Zn is an important micronutrient for both plants and animals. An estimated 17% of the world population, or around 1.1 billion people, are at the risk of zinc (Zn) deficiency. The deficiency has been related to adverse pregnancy outcomes, stunted growth, premature deaths, immune system dysfunctions, neuro-behavioral disorders, and recently with the failure to recover from COVID-19. These health risks associated with Zn deficiency have compelled FAO and WHO to recommend Zn fortification of diet. Correcting Zn deficiency is a challenge due to several reasons. Close to half of the agricultural soils are Zn deficient, and chemical Zn fertilizers are costly and ineffective. Developing Zn-rich crops through plant breeding and genetic engineering is challenging. Zn-dense diet is costly and cannot be implemented in the low-income region most affected by Zn deficiency. Lack of consensus among regulatory bodies on defining and diagnosing Zn deficiency in plants and Humans. Awareness and other sociocultural issues. Among the most important available solutions are zinc biofortification of the cereal crops, use of zinc biofertilizers, development of Zn-efficient crops with reduced phytate content. The use of Zn supplements, dietary modification, and diversification, especially with fish, are proposed as the most accessible and affordable solutions. Awareness programs in areas suffering the most from Zn deficiency are required. Despite the suggestions from FAO and WHO, global efforts to combat Zn deficiency matching those for combating diseases like HIV are not in place. Coordinated efforts of the international community, especially policy-makers, agricultural scientists, dieticians, physicians, and others, are required to address the issue of hidden hunger.     

Sorption and desorption of radioselenium on calcareous soil and its solid components

The effect of different solid soil components of calcareous soils on the retention of SeO₃ has been investigated by a batch technique and selective extraction method. The sorption and desorption isotherms of SeO₃ on the untreated calcareous soil and the three treated soils were determined at 20°C, pH 7.8±0.2 and in the presence of 0.001M CaCl₂. It was found that all isotherms are linear, the sorption-desorption hysteresis for untreated soil and treated soils is obvious and the retention of SeO₃ in calcareous soil is mainly attributed to the oxides.     

Sorption and desorption of radioselenium on calcareous soil and its solid components

The effect of different solid soil components of calcareous soils on the retention of SeO₃ has been investigated by a batch technique and selective extraction method. The sorption and desorption isotherms of SeO₃ on the untreated calcareous soil and the three treated soils were determined at 20°C, pH 7.8±0.2 and in the presence of 0.001M CaCl₂. It was found that all isotherms are linear, the sorption-desorption hysteresis for untreated soil and treated soils is obvious and the retention of SeO₃ in calcareous soil is mainly attributed to the oxides.     

Comparison of microwave-assisted digestion procedures for total trace element content determination in calcareous soils

The aim of the study was to determine total trace (Cd, Co, Cr, Cu, Mn, Pb and Zn) and major (Al and Fe) element concentrations in calcareous soils using microwave-assisted digestion procedures. The literature showing lack of consensus regarding digestion procedures and unsatisfying recoveries for calcareous materials, four procedures using various acid combinations (HCl, HNO₃, H₂O₂, HF) and volumes were tested using a certified reference material (CRM 141R) and natural calcareous soil samples. Digests were analysed by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Repeatability (R.S.D. <5%) and recoveries (82-116%) showed that the procedures were precise and accurate for most elements. Five calcareous soil samples from a Champagne vineyard plot were, then, subjected to these procedures. In calcareous materials, the presence of HF resulted in Al being severely underestimated (recovery <5%) and Co overestimated (recovery >124%) due to complex formation or spectrochemical interferences, respectively. As digestion was not significantly influenced by the addition of H₂O₂, the procedure corresponding to Aqua regia (HCl-HNO₃) appeared as the best compromise and was selected for further multielemental environmental studies on calcareous materials, even if the absence of HF could lead to incomplete digestion of accessory silicate minerals. Results for a vineyard plot showed that the soils were contaminated (3.65 mg kg⁻¹ Cd, 67 mg kg⁻¹ Cr, 278 mg kg⁻¹ Cu, 143 mg kg⁻¹ Pb and 400 mg kg⁻¹ Zn) as a consequence of urban waste and copper-treatment applications.     

Nature of the HCl-soluble sulfate in the sequential extraction for sulfur speciation in soils

Thirty soils collected from different regions of China were used to investigate the nature of HCl-soluble sulfate (HCl-S) and to evaluate the importance of HCl-S for sulfur speciation in soils. The soils were first extracted with NaH₂PO₄ solution to remove water-soluble and adsorbed sulfate, followed by extraction in 1 mol/l HCl at room temperature, minimizing the hydrolysis of organic sulfur into sulfate. Excellent linear correlations (r = 0.986) were found between the HCl-S and the carbonate contents in these soils, indicating HCl-S was mainly the carbonate-occluded inorganic sulfate in calcareous soils, averaging for 39% of total sulfur. However, the traditionally recognized major form of soil sulfate (water-soluble and adsorbed sulfate) only account for 7.5% of total sulfur. The non-calcareous soils were also found to contain some of HCl-S (6.9% of total sulfur). Large errors will occur in the determination of ester sulfur if HCl-S is not subtracted from the HI-reducible sulfur, especially in calcareous soils and soils containing little organic matter, which was the common practice in sulfur speciation studies. The reasonableness of including HCl-S in the subtraction method to determine ester sulfur was further verified by the good correlations between ester sulfur and organic carbon content in the soils Received: 21 February 1996 / Revised: 10 June 1996 / Accepted: 14 June 1996     

Anion exchange liquid chromatography--inductively coupled plasma-mass spectrometry detection of the Co2+, Cu2+, Fe3+ and Ni2+ complexes of mugineic and deoxymugineic acid

Phytosiderophores, such as mugineic and deoxymugineic acid, are produced by graminaceous plant species in response to Fe deficiency conditions normally experienced in calcareous and alkaline non-calcareous soils. As these phytosiderophores have the ability to form thermodynamically stable complexes with other metal cations present in the growing medium, they have also been implicated in the transport and bioavailability of these metals in the environment. However, routine analytical methodology to detect the various metal complexes formed by these phytosiderophores is lacking. Therefore, as these complexes are negatively charged over a wide range of pH values, anion exchange liquid chromatography (AE LC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) was investigated as a means to separate and quantify these complexes. The metal-phytosiderophore complexes were prepared at pH 7 and separated by NaOH or NH4NO3 gradient elution on a Dionex AS11 anion exchange column. Of the metals tested only the Co2+ and Ni2+ complexes of mugineic and deoxymugineic acid were detected when using a 0-20mM NaOH gradient elution profile. However, the phytosiderophore complexes of Cu2+ and Fe3+ were also detected when using NH4NO3 as the mobile phase at pH 7. Base-assisted hydrolysis of the latter two complexes is proposed to explain their apparent 'instability' in the high pH NaOH mobile phase. The absolute detection limits of the developed methodologies for these metal complexes ranged from 0.1 to 2.8pmol. As phytosiderophore complexes with Cd2+ and Zn2+ were not detected, it was concluded that the dissociation kinetics of these metal-phytosiderophore complexes were too rapid for these complexes to be observed in the present chromatographic conditions.     

Microwave extraction of heavy metals from wet rhizosphere soils and its application to evaluation of bioavailability

Single microwave extraction of heavy metals Cr, Ni, Zn, Cu, Cd, and Pb by the extractants CaCl(2), EDTA, CH(3)COOH and HCl has been established. The experimental conditions were optimized. A microwave power of 60% and an extraction time of 25 min were adopted. Comparison of microwave extraction and conventional extraction methods revealed that results obtained by microwave techniques were generally in a good agreement with those obtained by use of extraction methods; use of the former resulted in substantial time saving and a better precision, however. Microwave extraction was used to evaluate the bioavailability of heavy metals in soils. Single correlation analysis was performed to establish the relationship between the concentrations of the extractable heavy metals in wet rhizosphere soils and their concentrations in wheat ( Troticum aestivum L.) grown on the soils under greenhouse conditions. The correlation coefficients between the extractable metals in soils and their concentrations in wheat roots were found to be 0.5398-0.7819, 0.6425-0.8073, 0.5568-0.8276, 0.5851-0.6087 for the extractants CaCl(2), EDTA, CH(3)COOH, and HCl, respectively.     

城市土壤对铅和锌的吸附热力学特征

采用批量法对温州景山森林公园5种不同城市土壤对Pb和Zn的吸附热力学行为进行了研究。结果表明,吸附等温线符合Freundlich等温式和Temkin等温式,相关系数都在0．85以上,5种土壤对Ph的吸附强度由高到低的次序为C,E,B,A,D,对Zn的吸附强度由高到低的次序为C,E,D,B,A。     

Sorption and desorption of radiocesium on calcareous soil: Results from batch and column investigations

The sorption and desorption of radiocesium on a calcareous soil from Jiuqian County of Gansu Province (China) were studied by using batch and column experiments. The sorption-desorption isotherms and the breakthrough curves, displacement curves on the whole soil and two treated soils were determined. Based on these results, it was found that the sorption and retention of cesium are mainly determined by the clay minerals, that the sorption-desorption hysteresis of cesium on the calcareous soil is obvious and that the organic matter has a little positive contribution and the calcium carbonate has a little negative contribution to the sorption of cesium on the whole soil. The results from batch experiments were consistent with the results from column experiments.