无滴农用薄膜生产新工艺

本文论述了国内外无滴农用薄膜的应用和生产状况及其发展前景，同时介绍了涂敷性无滴技术，防雾滴涂料的性能与合成工艺。     

Determination of chromium in human milk, serum and urine by electrothermal atomic absorption spectrometry without preliminary ashing

In the present study a Perkin-Elmer 5000 atomic absorption spectrometer equipped with a tungsten--iodide lamp for improved background correction at the 357.9 nm chromium absorption line and an HGA 500 graphite furnace were employed for the direct determination of chromium in human serum, milk and urine. The method of standard additions was used: 0.25-0.75 ng Cr was added to 1 ml samples. Except for urine samples, a dilution of 1 + 1 to 1 + 2 with H2O was necessary in order to obtain correct calibration curves. The average concentration of chromium in all the samples of normal subjects was less than 0.5 ng Cr ml-1. The day-to-day variation for all of the pooled samples was around 10% (relative standard deviation). For urine, the accuracy of the method was tested by comparing the results of another laboratory for the same two round robin samples. Excellent agreement was found between the present method and those of the other laboratory that had used isotope dilution--mass spectrometry and continuum source wavelength modulated echelle--atomic absorption spectrometry to define the chromium concentration in the samples. The detection limit of the method, 0.05 ng Cr ml-1 for urine and serum and 0.1 ng Cr ml-1 for human milk, was sufficient for the biological fluids analyzed. The method was employed for the determination of chromium in 24-h urine samples of maturity onset diabetics supplemented with 20 or 200 micrograms Cr3+ d-1 for six weeks. It was shown that the 24-h urinary chromium excretion accurately indicates the daily dietary chromium intake of these patients.     

Assessment of Algerian sorghum protein quality [Sorghum bicolor (L.) Moench] using amino acid analysis and in vitro pepsin digestibility

To assess the protein quality and the nutritive value of seven Algerian local sorghum cultivars, the in vitro pepsin digestibility was determined, which ranged from 25.0% to 65.0%, and the amino acid composition of each cultivar was compared with other sorghum cultivars. In addition, the amino acid scores (AAS) and the protein digestibility-corrected amino acid scores (PDCAAS) were calculated. Relative to the WHO protein standard, most of the sorghum cultivars tested, scored very high AAS, with values ranging between 0.9 and 2.6 except for lysine, methionine and cysteine. The PDCAAS were high for Ain Salah cultivars AS1 and AS3, however, all other cultivars showed low values except for leucine. This study confirmed that in terms of both quantity and quality, sorghum proteins could serve as a source of essential amino acids and as a potential source of proteins in the future.     

某金属冶炼厂区周围农村居民膳食无机砷暴露评估

目的对广西某金属冶炼厂区周围农村居民膳食无机砷暴露情况进行风险性评估,为预防控制慢性砷危害提供依据。方法在广西某金属冶炼厂周围农村村屯,按照随机抽样的原则对该村屯居民自种自供的大米、蔬菜和养殖的鸡、鸭等食品采样,用GB/T5009.11—2003《食品中总砷及无机砷的测定》方法检测上述食品无机砷的含量,按照国家标准进行评价;同时结合当地居民膳食摄入量(食物频次法),并参考2002年广西营养与健康调查得出的农村居民各类食物每日消费量分别计算出当地居民膳食无机砷暴露量,利用JECFA提出的无机砷每公斤体重每周允许摄入量[PTWI为0.015mg/(kgBW·week)]进行风险性评估。结果该村种植的食用植物性农产品无机砷总体超标率为60.29%,其中大米超标率高达87.10%,平均含量为0.65mg/kg,最大超标15.5倍;蔬菜超标68.42%,平均含量0.16mg/kg;饲养家禽类食物总体无机砷超标率54.76%。每标准人每日平均、P90、P97.5膳食无机砷摄入量分别为0.2149mg、0.3900mg、0.4642mg,分别是JECFA提出的无机砷每日允许摄入量(ADI)的1.66倍、3.02倍、3.60倍(其中参考2002年农村居民食物摄入量计算为ADI的2.0倍)。结论该厂区周围村屯食用农产品无机砷污染严重,居民尤其是高消费人群膳食无机砷暴露量明显超过ADI值,存在危害健康风险。     

轮胎橡胶复合材料的制备方法

环氧化天然橡胶是一种对天然橡胶进行环氧化改性得到的新型聚合物,具有优异的气密性、耐油性以及良好的黏着性,同时具有良好的抗湿滑性与较低的滚动阻力,在高性能绿色轮胎的应用中有广阔的应用前景。以环氧化天然橡胶复合材料为例,探究制备方法和过程。     

镇江部分食用农产品污染物调查

目的 了解镇江肿瘤观察区和对照区产农产品污染物状况,为筛查肿瘤危险因素提供参考.方法应用国家标准规定方法检测农产品中铅、镉、汞、黄曲霉毒素、残留农药.结果91份样品,检出铅38份、镉44份、汞21份,观察区与对照区金属污染物检出率差异无统计学意义,铅、汞检出量差异无统计学意义,镉检出量差异有统计学意义.原粮24份,2份检出黄曲霉毒素B1,黄曲霉毒素B2、G1、G2均未检出.检测原粮、蔬菜、水果、茶叶农药残留为24份、48份、12份、7份,分别检出农药11份、30份、3份、3份.检出的农药有乐果、毒死蜱、甲胺磷、敌敌畏、马拉硫磷、克百威、三氯杀螨醇、甲基毒死蜱、莠去津等.两区农产品农药检出率差异无统计学意义,检出量差异有统计学意义.两区原粮、蔬菜农药检出量比较差异有统计学意义,两区有机磷农药检出量与肿瘤调查结果呈正相关r= 0.97,有剂量-效应关系.结论 镇江地产农产品镉与农药污染可能是影响村民健康的潜在危险因素之一.     

Physicochemical characterization of alkali treated fractions from corncob and wheat straw and the production of nanofibres

Raw cereal materials (CM) (corncob and wheat straw) were alkaline treated to produce insoluble fibrous residues (IF) and soluble fibrous residues (SF). Physicochemical properties of each portion were evaluated. CM contained high amounts of dietary fibre (DF; 49.87–68.65%), while IF and SF mainly contained insoluble and soluble DF, respectively. CM and IF contained essential minerals (calcium, copper, iron, potassium, magnesium and phosphorus) while SF was free from heavy metals. CM and IF also exhibited DPPH radical scavenging ability (54.25 to 77.24%), good emulsification ability (3.73–5.29%) and emulsion stability (75.00–86.94%), mineral binding capacity (calcium, copper, iron, zinc), water holding capacity (2.82–6.01 g_water/g_sample) and oil holding capacity (2.61–4.00 g_oil/g_sample). IF and SF could be potentially developed into new functional food materials. The successful production of SF into nanofibres by electrospinning showed potential applications as delivery systems for bioactive and functional ingredients.     

Empirical Analysis of Agricultural Cultural Resources Value Evaluation under DEA Model

Agricultural culture is a productive activity about education and management. It aims at high efficiency and high quality, uses technology as its means, and takes nature as its carrier. Agricultural cultural resources are the product of the rapid development of modern economy. It promotes the development of the national economy and profoundly affects people's production and life. DEA model, also known as data envelope analysis method, is an algorithm that uses multiple data decision units for input and output training to obtain the final model. This article explains the concept and basic characteristics of agricultural culture. Through questionnaire surveys and expert interviews, we collected development data, screened human, material, and financial data, and calculated information on economic and social resources. On this basis, this paper establishes the evaluation index of agricultural culture based on DEA model. Then, through empirical analysis from a specific perspective, it can be concluded that increasing human, material and financial input can achieve economic and social benefits. Generally speaking, cultural investment can promote the development of the industry. The research results of this paper laid a theoretical foundation for the development of agricultural culture, and put forward a development model focusing on technology development, improving investment efficiency, and investing in material resources.     

Modeling trade-offs among ecosystem services in agricultural production systems

Although agricultural ecosystems can provide humans with a wide set of benefits agricultural production system management is mainly driven by food production. As a consequence, a need to ensure food security globally has been accompanied by a significant decline in the state of ecosystems. In order to reduce negative trade-offs and identify potential synergies it is necessary to improve our understanding of the relationships between various ecosystem services (ES) as well as the impacts of farm management on ES provision. We present a spatially explicit application that captures and quantifies ES trade-offs in the crop systems of Llanada Alavesa in the Basque Country. Our analysis presents a quantitative assessment of selected ES including crop yield, water supply and quality, climate regulation and air quality. The study is conducted using semantic meta-modeling, a technique that enables flexible integration of models to overcome the service-by-service modeling approach applied traditionally in ES assessment.     

Avocado (Persea americana Mill.) by-products and their impact: from bioactive compounds to biomass energy and sorbent material for removing contaminants. A review

Avocado industry produces enormous by-products and represents an important source of raw material in food and non-food applications. This review aims to focus the attention on the valorisation of avocado wastes recycling to produce different materials with important industrial and environmental impacts. In fact, peels and seeds can be reused in food and cosmetic fields due to the presence of bioactive ingredients such as polyphenols; thanks to their antioxidant and antinflammatory activities. In addition, both peels and seeds can be reused in the production of carbonaceous materials with important consequences for environmental pollution in the removal of contaminants from water. Interesting applications of avocado wastes in photocatalysis and biofuel production are also discussed. All the utilisations attest the great potential of recycling avocado by-products, a little known resource.