火焰原子吸收光谱法测定虎杖中微量元素的含量

采用火焰原子吸收光谱法测定了虎杖中的Ca、Mg、Zn、Cu、Mn、Fe、Pb、Cr和Cd含量。结果表明:虎杖中微量元素钙和镁分别达到2466μg/g和789.1μg/g,锌、铁含量较高,铜、铅和铬含量较低,镉未检测出,回收率为83.47%~103.0%,相对标准偏差(RSD)介于4.23%~16.72%,该法简单、快速、准确,结果令人满意。     

蜂蜜中金属元素含量的测定

采用了火焰原子吸收分光光度法测定东北蜂蜜和槐花蜂蜜中金属元素钾、钠、镁、钙、锌、铁、铜、锰.样品预处理采用湿法消解与干法灰化两种方法进行对比.测定结果为东北蜂蜜湿法消解:80.58、5.24、2.90、7.29、0.52(mg/100 g);干法灰化:69.66、5.09、2.11、3.94、0.43(mg/100g).槐花蜂蜜湿法消解:22.01、8.03、2.12、8.05、0.12(mg/100 g);干法灰化:16.32、3.55、0.71、3.05、0.06(mg/100g),其余元素低于检出限未检出.回收率:90%~112%,RSD:1%~4%.     

ICP-AES法测定山西地区几种醋中的金属元素

采用HNO_3微波消解法对山西地区生产的几种醋的样品进行处理,利用ICP-AES仪测定样品中钙、钾、镁、锌、铁、铜、铬、锰、镍等9种金属元素的含量。实验结果表明,这几种醋中均富含钙、钾、镁、锌、铁、锰等对人体有益的金属元素,铬、镍等有害元素含量低于食品安全国家标准食品中污染物限量。该方法回收率在85%~102%,相对标准偏差≤2.97%,检出限介于0.001μg/mL~0.174μg/mL。为指导人们合理膳食提供科学依据。     

北京中力恒优精细化工有限公司

<正>独家研发,生产、经销的下述产品一、PVC热稳定剂化工原料:1.甘油锌白色细粉,无异味总锌量:40%~42%单甘油钙总钙量:(27±0.5)%双甘油钙总钙量:(18%士0.5)%2.甘油镁总镁量:20%~21%3.新合成水滑石301,总镁量:24%~15%总锌量:10%~12%总铝量:4%~5%二、PVC无毒热稳定剂:结晶水:≤10%4-1.GPS钙锌热稳定剂,总锌量:(12%±0.5)%总钙量:(11%±0.5)%4-2.CZM钙锌镁热稳定剂,总锌量:8%~9%钙镁合量:(18±0.5)%     

原子吸收光谱法测定蒽油中金属含量

研究了原子吸收光谱法测定蒽油中铁、钾、镁、钠、钙、铜等金属含量。先将蒽油试样经过灼烧灰化后,用盐酸溶解,采用火焰原子吸收光谱法测定其中的铁、钾、镁、钠、钙、铜等金属含量。实验表明,铁和铜含量在0~5mg/L范围内,钾和镁含量在0~0.4mg/L范围内,钠含量在0~0.8mg/L范围内,钙含量在0~8mg/L范围内均显现良好的线性关系,相关系数均为r=0.999,铁、钾、镁、钠、钙、铜加标回收率均在95%~105%内。     

药用纳米牡蛎碳酸钙中营养元素的测定研究

针对药用纳米牡蛎碳酸钙中锌、铁、镁营养元素含量的标识问题,用原子吸收光谱法测定其含量.对测定条件进行了优化,考察了方法的线性范围、检出限、精密度及回收率.线性方程分别为:锌,Y=0.157 1 x 0.000 7;铁,Y=0.048 9x-0.000 1;镁,Y=0.456 1x 0.0005.三元素的检出限分别为:p(锌)=0.05 mg/L;P(铁)=0.10 mg/L;P(镁)=0.01 mg/L.回收率分别为:锌,99.31%;铁,98.13%;镁,99.89%.研究结果表明:药用纳米牡蛎碳酸钙中富含对人体有益的锌、铁、镁3种元素.用原子吸收光谱法对营养元素含量进行测定,方法简便快捷,重复性好,准确度高.     

小叶麦冬果实中微量元素的光谱测定

采用空气-乙炔火焰原子吸收法,对小叶麦冬果实的钙、钠、镁、锌、锰、铜、钾、铁8种元素进行了含量的测定。选择了最佳电离抑制剂和酸性介质。本实验以氯化铯为电离抑制剂,盐酸浓度控制在2%以内,用氯化锶消除磷酸对钙的干扰,使吸光值稳定,用标准曲线法进行测定,获得了满意的效果。该测定方法简便、快速、准确。结果表明,小叶麦冬果实中钾、钙等微量元素含量丰富,含钾17.09mg/g、钙8.22mg/g。     

干、湿法消解-火焰原子吸收法测定多种食品中钙元素的含量

经干法灰化、湿式消解两种方法预处理,运用火焰原子吸收法测定多种食品中钙元素的含量。结果表明,钙元素在(1~10)μg·m L-1范围内,线性关系良好,相关系数为0.9932。所测13种食品中,虾皮的钙含量最高,为766.61mg/100g(湿法),香菇的钙含量最低,为5.16mg/100g(湿法)。干法灰化加标回收率在90.20%~103.20%,湿法消解加标回收率在90.50%~104.95%,两者相对标准偏差均小于4%。     

ICP-OES法测定二次盐水中钙、镁、铁含量

利用电感耦合等离子体发射光谱仪(ICP-OES),测定二次精制盐水中钙、镁、铁的含量。在实验条件下,钙、镁、铁等元素加标回收率良好,均在90%～110%之间;钙、镁、铁的检出限分别为0.0797、0.0900、0.2010μg/L;钙、镁、铁的相对标准偏差分别为2.84%、2.72%、10.79%,精密度良好。用本法测定二次盐水结果令人满意。     

烟梗草木灰中微量金属元素含量分析

烟梗草木灰是属于农作物秸秆草木灰之一,含钾丰富,除此之外它还含有铜、铁、锌、锰、钙、镁、铅、铬、镉、汞、砷等微量金属元素。本文利用微波消解-原子吸收法及微波消解-原子荧光法对烟梗草木灰中微量金属元素含量进行测定,结果表明:烟梗草木灰中,各微量元素的含量分别为含量分别为铁(1. 46%)、铜(0. 14%)、锌(0. 18%)、钙(5. 16%)、镁(1. 87%)、锰(0. 0575%)、铅(0. 0525%)、镉(0. 0075%)、铬(0. 0375%)、汞(0. 0004%)、砷(0. 0035%)。烟梗草木灰中含钙、铁、镁含量丰富,重金属铅、镉、铬、汞、砷含量在国家标准(GB/T 23349-2009)限量范围之内。     

Sirt3, Mitochondrial ROS, Ageing, and Carcinogenesis

One fundamental observation in cancer etiology is that the rate of malignancies in any mammalian population increases exponentially as a function of age, suggesting a mechanistic link between the cellular processes governing longevity and carcinogenesis. In addition, it is well established that aberrations in mitochondrial metabolism, as measured by increased reactive oxygen species (ROS), are observed in both aging and cancer. In this regard, genes that impact upon longevity have recently been characterized in S. cerevisiae and C. elegans, and the human homologs include the Sirtuin family of protein deacetylases. Interestingly, three of the seven sirtuin proteins are localized into the mitochondria suggesting a connection between the mitochondrial sirtuins, the free radical theory of aging, and carcinogenesis. Based on these results it has been hypothesized that Sirt3 functions as a mitochondrial fidelity protein whose function governs both aging and carcinogenesis by modulating ROS metabolism. Sirt3 has also now been identified as a genomically expressed, mitochondrial localized tumor suppressor and this review will outline potential relationships between mitochondrial ROS/superoxide levels, aging, and cell phenotypes permissive for estrogen and progesterone receptor positive breast carcinogenesis.     

Cyanobacteria,Cyanotoxins, and Neurodegenerative Diseases: Dangerous Liaisons

The prevalence of neurodegenerative disease (ND) is increasing, partly owing to extensions in lifespan, with a larger percentage of members living to an older age, but the ND aetiology and pathogenesis are not fully understood, and effective treatments are still lacking. Neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis are generally thought to progress as a consequence of genetic susceptibility and environmental influences. Up to now, several environmental triggers have been associated with NDs, and recent studies suggest that some cyanotoxins, produced by cyanobacteria and acting through a variety of molecular mechanisms, are highly neurotoxic, although their roles in neuropathy and particularly in NDs are still controversial. In this review, we summarize the most relevant and recent evidence that points at cyanotoxins as environmental triggers in NDs development.     

A Comparative Study of Molecular Structure,pKa, Lipophilicity,Solubility, Absorption and Polar Surface Area of Some Antiplatelet Drugs

Theoretical chemistry methods have been used to study the molecular properties of antiplatelet agents (ticlopidine, clopidogrel, prasugrel, elinogrel, ticagrelor and cangrelor) and several thiol-containing active metabolites. The geometries and energies of most stable conformers of these drugs have been computed at the Becke3LYP/6-311++G(d,p) level of density functional theory. Computed dissociation constants show that the active metabolites of prodrugs (ticlopidine, clopidogrel and prasugrel) and drugs elinogrel and cangrelor are completely ionized at pH 7.4. Both ticagrelor and its active metabolite are present at pH = 7.4 in neutral undissociated form. The thienopyridine prodrugs ticlopidine, clopidogrel and prasugrel are lipophilic and insoluble in water. Their lipophilicity is very high (about 2.5–3.5 logP values). The polar surface area, with regard to the structurally-heterogeneous character of these antiplatelet drugs, is from very large interval of values of 3–255 Ų. Thienopyridine prodrugs, like ticlopidine, clopidogrel and prasugrel, with the lowest polar surface area (PSA) values, exhibit the largest absorption. A high value of polar surface area (PSA) of cangrelor (255 Ų) results in substantial worsening of the absorption in comparison with thienopyridine drugs.     

Isolation,Bioactivity, and Production of ortho-Hydroxydaidzein and ortho-Hydroxygenistein

Daidzein and genistein are two major components of soy isoflavones. They exist abundantly in plants and possess multiple bioactivities. In contrast, ortho-hydroxydaidzein (OHD) and ortho-hydroxygenistein (OHG), including 6-hydroxydaidzein (6-OHD), 8-hydroxydaidzein (8-OHD), 3′-hydroxydaidzein (3′-OHD), 6-hydroxygenistein (6-OHG), 8-hydroxygenistein (8-OHG), and 3′-hydroxygenistein (3′-OHG), are rarely found in plants. Instead, they are usually isolated from fermented soybean foods or microbial fermentation broth feeding with soybean meal. Accordingly, the bioactivity of OHD and OHG has been investigated less compared to that of soy isoflavones. Recently, OHD and OHG were produced by genetically engineering microorganisms through gene cloning of cytochrome P450 (CYP) enzyme systems. This success opens up bioactivity investigation and industrial applications of OHD and OHG in the future. This article reviews isolation of OHD and OHG from non-synthetic sources and production of the compounds by genetically modified microorganisms. Several bioactivities, such as anticancer and antimelanogenesis-related activities, of OHD and OHG, are also discussed.     

Correlation among Antioxidant, Antimicrobial, Hemolytic, and Antiproliferative Properties of Leiothrix spiralis Leaves Extract

The biological activities of a plant extract depend on a complex sum of individual properties including the antioxidant activity. Several biological activities protect against the harmful action of reactive oxygen species (ROS), and here we focused our attention on the relationship between the biological activities tested and the antioxidant properties. In this study, the total flavonoid content as well as the antioxidant, antimicrobial, hemolytic and cytotoxicity activities of the methanolic extract of Leitothrix spiralis leaves were evaluated. The extract showed a total flavonoid content of 19.26% and the chemical characterization by HPLC-PAD confirmed the presence of flavonoids as the major secondary metabolite compounds. Significant antioxidant activity (IC(50) = 1.743 μg/mL ± 0.063) was demonstrated and was effective against Gram-negative organisms and all Candida strains tested, and showed an ability to inhibit hyphal formation. Non-hemolytic and antiproliferative activity could be demonstrated.     

Selenium Deficiency Due to Diet,Pregnancy, Severe Illness,or COVID-19—A Preventable Trigger for Autoimmune Disease

The trace element selenium (Se) is an essential part of the human diet; moreover, increased health risks have been observed with Se deficiency. A sufficiently high Se status is a prerequisite for adequate immune response, and preventable endemic diseases are known from areas with Se deficiency. Biomarkers of Se status decline strongly in pregnancy, severe illness, or COVID-19, reaching critically low concentrations. Notably, these conditions are associated with an increased risk for autoimmune disease (AID). Positive effects on the immune system are observed with Se supplementation in pregnancy, autoimmune thyroid disease, and recovery from severe illness. However, some studies reported null results; the database is small, and randomized trials are sparse. The current need for research on the link between AID and Se deficiency is particularly obvious for rheumatoid arthritis and type 1 diabetes mellitus. Despite these gaps in knowledge, it seems timely to realize that severe Se deficiency may trigger AID in susceptible subjects. Improved dietary choices or supplemental Se are efficient ways to avoid severe Se deficiency, thereby decreasing AID risk and improving disease course. A personalized approach is needed in clinics and during therapy, while population-wide measures should be considered for areas with habitual low Se intake. Finland has been adding Se to its food chain for more than 35 years—a wise and commendable decision, according to today’s knowledge. It is unfortunate that the health risks of Se deficiency are often neglected, while possible side effects of Se supplementation are exaggerated, leading to disregard for this safe and promising preventive and adjuvant treatment options. This is especially true in the follow-up situations of pregnancy, severe illness, or COVID-19, where massive Se deficiencies have developed and are associated with AID risk, long-lasting health impairments, and slow recovery.     

Impact of Phosphate,Potassium, Yeast Extract,and Trace Metals on Chitosan and Metabolite Production by Mucor indicus

In this study the effects of phosphate, potassium, yeast extract, and trace metals on the growth of Mucor indicus and chitosan, chitin, and metabolite production by the fungus were investigated. Maximum yield of chitosan (0.32 g/g cell wall) was obtained in a phosphate-free medium. Reversely, cell growth and ethanol formation by the fungus were positively affected in the presence of phosphate. In a phosphate-free medium, the highest chitosan content (0.42 g/g cell wall) and cell growth (0.66 g/g sugar) were obtained at 2.5 g/L of KOH. Potassium concentration had no significant effect on ethanol and glycerol yields. The presence of trace metals significantly increased the chitosan yield at an optimal phosphate and potassium concentration (0.50 g/g cell wall). By contrast, production of ethanol by the fungus was negatively affected (0.33 g/g sugars). A remarkable increase in chitin and decrease in chitosan were observed in the absence of yeast extract and concentrations lower than 2 g/L. The maximum chitosan yield of 51% cell wall was obtained at 5 g/L of yeast extract when the medium contained no phosphate, 2.5 g/L KOH, and 1 mL/L trace metal solution.