Trace Elements in Pleurotus Ostreatus,P. Eryngii,and P. Nebrodensis Mushrooms Cultivated on Various Agricultural By-Products

Abstract

Mushrooms are efficient accumulators of essential and toxic elements. Although oyster (Pleurotus spp.) mushrooms are widely commercialized and consumed, few data exist regarding trace elements content and bioaccumulation in cultivated P. ostreatus and P. eryngii, while no data are available for P. nebrodensis. The contents of Al, As, Ba, Cd, Co, Cr, Cs, Cu, Fe, K, Mn, Na, Ni, Pb, Rb, Sr, V, and Zn were monitored using inductively coupled plasma-mass spectrometry (ICP-MS) and atomic emission spectrometry (AES) in P. ostreatus, P. eryngii, and P. nebrodensis mushrooms and their cultivation substrates that include wheat straw (WHS), grape marc (GMC), olive leaves (OLV), and two-phase olive mill wastes (OMW), separately or in mixtures. Bioaccumulation factors (BAFs) less than 0.3 were obtained for Al, Ba, Co, Cr, Fe, Mn, Ni, Pb, Sr, and V; BAFs exceeding 1 for K?>?Zn?>?Cd?>?Cr?>?Rb?>?As, while the BAFs for Na were less 0.7. Mushrooms grown on OLV and OMW presented lower BAFs than those grown on WHS and GMC for all elements except for K, Cd, and Cu. P. ostreatus was an effective accumulator for Cr, Fe, and Zn; P. eryngii for Al, Cs, Ni, and V; and P. nebrodensis for As and Cd. The estimated daily intakes (μg kg^?1 body weight) from mushroom consumption were less than 0.010 for As, Cd, Co, Cs, Pb, and V, 0.010–0.10 for Ba, Cr, Ni, and Sr, 0.10–5.0 for Al, Cu, Fe, Mn, Rb, and Zn, 65–83 for Na, and 858–1030 for K. Overall, the mushrooms studied provide significant amounts of K, adequate amounts of Mn and Zn and low amounts of Na and toxic elements.     

Aeroelastic response of a coupled rotor/fuselage system in hovering and forward flight

Summary The aeroelastic response analysis of a coupled rotor/fuselage system is approached by iterative solution of the blade aeroelastic response in the non-inertial reference frame fixed on the hub, and the periodic response of the fuselage in the inertial reference frame. A model of the coupled system hinged with the flap and lag hinges, the pitching bearing which may not coincide with the hinges, and the sweeping-blade configuration is established. The moderate-deflection beam theory and the two-dimensional quasi-steady aerodynamic model are employed to model the aeroelastic blade, all the kinetic and inertial factors are taken into account in a unified manner. A five-nodes, 15-DOFs pre-twisted nonuniform beam element is developed for the discretization of the blade, three rigid-body-motion DOFs are introduced for the motion of the hinges and the bearing. The Hamilton's principle is employed to evaluate the equation of motion of the blade. The derived nonlinear ordinary differential equations with time-dependent periodic coefficients are solved by a modified quasi-linearization method, which is developed for the higher DOF periodic system. The resulting periodic forces and moments exerted on the fuselage by all the blades are evaluated every time, when the converged nonlinear periodic response of the blade is obtained under the consideration of the equilibrium of the blades. The fuselage structure is simplified to be a beam structure, the governing equation is established in the inertial reference frame and a two-nodes beam element is used to discretize the flexible fuselage. The periodic response of the fuselage is solved by a simple shooting method. The iteration of the rotor/fuselage response is continued, until the aeroelastic responses of the blade and the fuselage converge simultaneously. Both the hovering and the forward flight states can be considered. The results of a computed numerical example by the developed program are presented to verify in practice the economy of the modeling as well as the reliability and efficiency of the corresponding solving methods. Received 4 May 1998; accepted 11 August 1998     

Influence of relative response factor in the determination of organic microcontaminants with isotopically labeled standards

The use of isotopically labeled internal standards in the analysis of organic microcontaminants entails the determination of relative response factors (RRFs) of the unlabeled with respect to the labeled compounds. RRFs were measured daily during 28 replicate polychlorobiphenyl (PCB) analyses on two different sets of samples. Daily RRFs allowed more precise results to be attained than those provided by mean RRFs, the latter being the mean of all the daily RRFs obtained during the same series of analyses. Analytical applications to food matrices are presented, including the PCB contamination profile of an olive oil and that found in a matrix of Italian national mean diet. Based on the latter sample, also the polycyclic aromatic hydrocarbon (PAH) daily intake of Italians is assessed. Seven PAHs are determined.     

我国食品卫生安全风险评估模型

食品卫生安全关系到国计民生,建立适合于我国的食品卫生安全保障体系尤为重要.人群食物摄入量模型用"对数正态分布"估计食物摄入量分布,在对国家依据气候、地理、经济等因素进行地域划分的基础上提出了能够保证小样本空间条件下采样均匀的"层次化样本分配模型"用于采样点的选取和各采样点样本数量的分配;污染物分布模型用"贝塔分布"估计食物中的污染物分布,并采用样本在时间轴上平移的方法解决了数据在时间上的不完整性问题;风险评估模型基于人群食物摄入量和食物污染物分布模型,提出"矩元法"对污染物摄入量进行评估,并给出了模型数值化求解和右分位点确定的相关算法.实验表明,风险评估模型所确定的右分位点能有效地反映当前食品卫生安全状况.     

How Different Snacks Produce a Distinct Effect in Salivary Protein Composition

Saliva secretion changes in response to different stimulation. Studies performed in animals and humans suggest that dietary constituents may influence saliva composition, although the dynamics of these changes, and how they are specific for each type of food, are little known. The objective of the present study was to access the short-term effects of different foods in salivation and salivary protein composition. Twelve participants were tested for four snacks (yoghurt, bread, apple and walnuts). Non-stimulated saliva was collected before and at 0′, 5′ and 30′ after each snack intake. Flow rate, total protein, alpha-amylase enzymatic activity and salivary protein profile were analyzed. Yoghurt and apple were the snacks resulting in higher salivary changes, with higher increases in flow rate and alpha-amylase activity immediately after intake. The expression levels of immunoglobulin chains decreased after the intake of all snacks, whereas cystatins and one pink band (proline-rich proteins—PRPs) increased only after yoghurt intake. Walnut’s snack was the one resulting in lower changes, probably due to lower amounts eaten. Even so, it resulted in the increase in one PRPs band. In conclusion, changes in saliva composition varies with foods, with variable changes in proteins related to oral food processing and perception.     

Determination of Lead and Cadmium in Milk by Electrothermal Atomic Absorption Spectophotometry

Abstract

The concentrations of lead and cadmium in different kinds of milk samples (powdered, infant formula, market, buffalo, condensed and human) were determined using electrothermal atomic absorption spectrophotometric technique. Among all the varieties of milk analysed, condensed milk was found to contain much higher amount of lead. Human milk as expected was found to have lowest concentration of these elements. The results were compared with the reported values of other countries. Daily intake of these toxic elements by adults and babies up to the age of six months through the consumption of various types of milk was estimated and compared with the tolerance levels.     

Uncertainty calculations in the certification of reference materials. 2. Homogeneity study

 Many reference materials undergo a batch certification, which implies that a small number of samples is taken from a batch, characterised, and these results are then assumed to be representative of all remaining samples. An important aspect in this design is the translation of the characterisation data to a single sample, as usually the laboratory will be using only one sample of the batch. This form of homogeneity is very important and can be influenced to a certain extent by well-designed sample preparation procedures. Another subsampling problem associated with many reference materials is that only a small test portion is drawn from the sample to carry out the measurement. Obviously, this test portion must be representative of the sample, otherwise the certified value is still not applicable. Both kinds of homogeneity tests are examined in the paper and evaluated using practical examples. Received: 31 May 2000 · Accepted: 29 July 2000     

基于IGRA-ISVD约减和RBF的森林火灾消防直升机需求预测模型

针对森林火灾消防直升机需求预测问题,提出了一种基于改进灰色关联分析(IGRA)和改进奇异值分解(ISVD)约简的径向基函数(RBF)神经网络预测模型.首先,基于既有研究梳理了森林火灾消防直升机需求预测指标体系;然后,在改进灰色关联分析和奇异值分解方法的基础上,分别对消防直升机需求预测数据信息进行属性约简和维度约简;最后,利用约简预测数据信息对RBF神经网络进行训练,进而构建消防直升机数量预测模型.案例分析和对比分析表明了本文所提方法的可行性和合理性.     

Design of helicopter rotor blades with actuators made of a piezomacrofiber composite

For reducing the vibration and noise of helicopter rotor blades, the method of their controlled twisting by using built-in deformation actuators is employed. In this paper, the influence of various design parameters of the blades, including the location of actuators made of a piezomacrofiber material, on the twist angle is evaluated. The results of a parametric analysis performed allowed us to refine the statement of an optimization problem for the rotor blades. __________ Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 1, pp. 77–86, January–February, 2008.     

中国硒研究历史回顾（上）

过去50年中,中国微量元素科学和营养科学中最重要的发现,就是认识了硒对人体健康的重要性。在诸多微量元素中,没有哪一个元素能像硒那样对人类产生如此深刻而又广泛的影响。从硒的生物必需性、硒的生物效应两面性、硒的抗癌性、硒的延寿作用及富硒产品开发五个方面回顾了中国的硒研究历程。