Formation of Self-Assembled Anticorrosion Films on Different Metals

The review will first discuss shortly the phenomenon of corrosion and enroll some general possibilities to decrease the rate of this deterioration. The stress will be laid upon the presentation of anticorrosive self-assembled molecular (SAM) layers as well as on the preparation technology that is a simple technique, does not need any special device, and can be applied on different solids (metals or non-metals) alone or in combination. The paper groups the chemicals (mainly amphiphiles) that can develop nanolayers on different pure or oxidized metal surfaces. The history of the self-assembled molecular layer will be discussed from the beginning of the first application up to now. Not only the conditions of the nanofilm preparation as well as their characterization will be discussed, but the methods that can evaluate the corrosion-inhibiting efficiency of the SAM layers under a corrosive environment will be demonstrated as well.     

Correlating the magic numbers of inorganic nanomolecular assemblies with a {Pd84} molecular-ring Rosetta Stone

Molecular self-assembly has often been suggested as the ultimate route for the bottom-up construction of building blocks atom-by-atom for functional nanotechnology, yet structural design or prediction of nanomolecular assemblies is still far from reach. Whereas nature uses complex machinery such as the ribosome, chemists use painstakingly engineered step-by-step approaches to build complex molecules but the size and complexity of such molecules, not to mention the accessible yields, can be limited. Herein we present the discovery of a palladium oxometalate {Pd₈₄}-ring cluster 3.3 nm in diameter; [Pd₈₄O₄₂(OAc)₂₈(PO₄)₄₂]^70- ({Pd₈₄} ≡ {Pd₁₂}₇) that is formed in water just by mixing two reagents at room temperature, giving crystals of the compound in just a few days. The structure of the {Pd₈₄}-ring has sevenfold symmetry, comprises 196 building blocks, and we also show, using mass spectrometry, that a large library of other related nanostructures is present in solution. Finally, by analysis of the symmetry and the building block library that construct the {Pd₈₄} we show that the correlation of the symmetry, subunit number, and overall cluster nuclearity can be used as a “Rosetta Stone” to rationalize the “magic numbers” defining a number of other systems. This is because the discovery of {Pd₈₄} allows the relationship between seemingly unrelated families of molecular inorganic nanosystems to be decoded from the overall cluster magic-number nuclearity, to the symmetry and building blocks that define such structures allowing the prediction of other members of these nanocluster families.     

Salivary antioxidant biomarkers in non-ferrous metals mine workers--a pilot study

J Oral Pathol Med (2012) 41 : 490–493 Objective: The purpose of the present study is to evaluate the relationships between occupational exposure to mine dust, salivary antioxidants and their possible implications in the pathogenicity of different exposure diseases. Material and methods: We studied 30 individuals with long‐term occupational exposure to non‐ferrous metal mine conditions and a control group consisted of 30 healthy volunteers. Salivary uric acid, gammaglutamyltransferase (GGT), albumin and the total antioxidant capacity (TAC) were measured. Results: Statistically significant differences in salivary GGT (P = 0.004), TAC (P < 0.001) and uric acid (P = 0.02) were noted between the two groups. A strong positive correlation between TAC and uric acid was recorded in controls (r = 0.76, P = 0.0002). Conclusions: Saliva may provide an important line of antioxidant defense in humans exposed to oxidant threats. These components may also serve as convenient biomarkers to monitor oxidant exposure.     

ICP-MS法测定喜炎平注射液中重金属及有害元素

目的 建立喜炎平注射液中17种重金属及有害元素的含量测定方法。方法 样品经消解后采用电感耦合等离子体质谱（ICP-MS）法测定,射频功率1 550 W;蠕动泵转速0.3 r/s;等离子气体积流量15 L/min;辅助气体积流量0.2 L/min;载气体积流量1 L/min;采样深度10 mm,重复次数为3次。结果 该方法下Li、Al、V、Cr、Fe、Co、Ni、Cu、As、Ag、Cd、Sn、Sb、Ba、Hg、Pb、Bi的检测限分别为9.584、49.858、0.504、3.016、51.209、0.142、1.116、0.675、0.924、1.421、0.403、2.770、0.711、3.584、0.590、0.411、0.169 ng/mL,定量限分别为28.933、151.085、1.528、9.139、155.179、0.429、3.381、2.046、2.799、4.312、1.220、8.394、2.155、10.861、1.965、1.244、0.513 ng/mL,各元素在一定质量浓度范围内,响应值与质量浓度的线性关系良好（r>0.999 1）,进样精密度RSD在0.8%~3.8%（n=12）,重复性RSD在0.7%~2.0%（n=6）,17种元素的加样回收率在95.7%~104.8%。20批大生产样品检测结果：Ag为未检出,Li和V为检出但低于定量限,Al、Ni、Cu、As、Ba、Hg、Pb最大质量浓度分别为0.685、0.013、0.007、0.006、0.208、0.070、0.027 μg/mL,Cr、Fe、Co、Cd、Sn、Sb、Bi为未检出或检出但低于定量限。结论 方法的专属性、线性、灵敏度、精密度、准确度、耐用性等均良好,可用于喜炎平注射液中Li、Al、V、Cr、Fe、Co、Ni、Cu、As、Ag、Cd、Sn、Sb、Ba、Hg、Pb、Bi 17种元素的含量测定,20批大生产样品中17种元素检测结果均小于限度要求,符合规定。     

FTIR-ATR结合膜富集技术测定中药材地龙中微量铜的含量

目的 利用傅里叶变换-衰减全反射红外光谱(FTIR-ATR)结合膜富集技术,建立中药材地龙中微量铜质量分数的快速、经济的测定方法.方法 首先,对30批校正集样品进行湿法消解,利用铜与金属络合剂1-(2-吡啶偶氮)-2-萘酚(PAN)发生络合反应,优化各种反应条件,包括pH 、PAN用量、反应时间.再将络合物抽滤富集在微孔滤膜上,采集其FTIR-ATR光谱,经9点平滑、一阶导数9点平滑等预处理后,利用随机森林回归算法建立其铜质量分数的定量校正模型.校正集按3∶1随机分配为训练集和测试集,对模型进行参数优化和评价.利用优化后模型预测广东、广西和福建3个产地地龙样品中铜的质量分数,并与ICP-MS测定结果进行比较.结果 最优模型预测3个产地地龙样品的质量分数在5.85～6.98 mg/kg之间,与ICP-MS分析结果相比,相对误差均小于20％.结论 本方法利用膜富集技术提高了FTIR-ATR的检测灵敏度,为中药材重金属元素的定量分析提供了一种新方法.     

Urinary excretion of platinum (Pt) following skin and respiratory exposure to soluble Pt at South African precious metals refineries

Adverse respiratory and skin health effects have been associated with occupational exposure to soluble platinum (Pt). However, the relationship between skin exposure and urinary Pt excretion has not yet been investigated. In this study we examined the relationship between skin and respiratory exposure to soluble Pt and urinary Pt excretion at two South African precious metals refineries.The skin and respiratory exposure to soluble Pt as well as the urinary Pt excretion of forty precious metals refinery workers was assessed simultaneously using Ghostwipes?, Methods for the Determination of Hazardous Substances method 46/2 and spot urine tests, respectively.The geometric mean for skin exposure to soluble Pt on four anatomical positions (palm, wrist, neck and forehead) was 0.008?μg/cm² [95% confidence interval (CI): 0.005-0.013?μg/cm²], while the geometric mean for respiratory exposure was 0.301?μg/m³ (95%CI: 0.151-0.601?μg/m³) and the geometric mean for urinary Pt excretion was 0.212?μg/g creatinine (95%CI: 0.169-0.265?μg/g creatinine). Partial correlations identified significant positive correlations between skin exposure, respiratory exposure and urinary Pt excretion (r?=?0.580 to 0.754).Skin and respiratory exposures to soluble Pt were both positively correlated with urinary Pt excretion, and both exposure routes should be considered when investigating occupational exposure to soluble Pt.     

Food survey: Levels and potential health risks of chromium,lead, zinc and copper content in fruits and vegetables consumed in Algeria

A food survey was carried out with the aim to investigate the levels of lead (Pb), zinc (Zn), copper (Cu) and chromium (Cr) in various fruits and vegetables sold in Algeria. Concentrations (mg/kg dry wt.) in selected foodstuffs were detected within the following ranges: 4–29.49, 11.17–49, 12.33–39.33 and 3–16.33 for Cu, Zn, Pb and Cr respectively. The food ingestion rate of the selected items was investigated by self-administered questionnaires which were filled by a total of 843 people randomly recruited at the exit of markets. The potential health risk for consumers was investigated by estimating the daily intake (EDI) and the target hazard quotient (THQ) for each heavy metal. For all foodstuffs, the EDI and the THQ were below the threshold values for Cu, Zn and Cr while they exceeded the thresholds for Pb (EDI: 15.66 μg Pb/kg body weight/day; THQ: 4.37), indicating an obvious health risk over a life time of exposure.     

Review of the Applications of Biomedical Compositions Containing Hydroxyapatite and Collagen Modified by Bioactive Components

Regenerative medicine is becoming a rapidly evolving technique in today’s biomedical progress scenario. Scientists around the world suggest the use of naturally synthesized biomaterials to repair and heal damaged cells. Hydroxyapatite (HAp) has the potential to replace drugs in biomedical engineering and regenerative drugs. HAp is easily biodegradable, biocompatible, and correlated with macromolecules, which facilitates their incorporation into inorganic materials. This review article provides extensive knowledge on HAp and collagen-containing compositions modified with drugs, bioactive components, metals, and selected nanoparticles. Such compositions consisting of HAp and collagen modified with various additives are used in a variety of biomedical applications such as bone tissue engineering, vascular transplantation, cartilage, and other implantable biomedical devices.     

Magnetic and Transport Properties of New Dual-Phase High-Entropy Alloy FeRhIrPdPt

High-entropy alloys (HEAs) are broadly explored from the perspective of mechanical, corrosion-resistance, catalytic, structural, superconducting, magnetic properties, and so on. In magnetic HEAs, 3d transition metals or rare-earth elements are well-studied compositional elements. We researched a magnetic HEA containing Fe combined with 4d and 5d transition metals, which has not been well investigated, and found a new dual-phase face-centered-cubic (fcc) HEA FeRhIrPdPt. The structural, magnetic, and transport properties were evaluated by assuming that FeRhIrPdPt is a mixture of FeRh₄, FeIr₄, FePd₄, and FePt₄, all with the fcc structure. The dual-phase is composed of a Rh- and Ir-rich main phase and a Pd- and Pt-rich minor one. FeRh₄ and FeIr₄ show spin freezings at low temperatures, while FePd₄ and FePt₄ are ferromagnetic. Two magnetic features can characterize FeRhIrPdPt. One is the canonical spin-glass transition at 90 K, and the other is a ferromagnetic correlation that appears below 300 K. The main and minor phases were responsible for the spin-glass transition and the ferromagnetic correlation below 300 K, respectively.     

Prospects for Electrical Performance Tuning in Ca3Co4O9 Materials by Metallic Fe and Ni Particles Additions

This work further explores the possibilities for designing the high-temperature electrical performance of the thermoelectric Ca₃Co₄O₉ phase, by a composite approach involving separate metallic iron and nickel particles additions, and by employing two different sintering schemes, capable to promote the controlled interactions between the components, encouraged by our recent promising results obtained for similar cobalt additions. Iron and nickel were chosen because of their similarities with cobalt. The maximum power factor value of around 200 μWm⁻¹K⁻² at 925 K was achieved for the composite with the nominal nickel content of 3% vol., processed via the two-step sintering cycle, which provides the highest densification from this work. The effectiveness of the proposed approach was shown to be strongly dependent on the processing conditions and added amounts of metallic particles. Although the conventional one-step approach results in Fe- and Ni-containing composites with the major content of the thermoelectric Ca₃Co₄O₉ phase, their electrical performance was found to be significantly lower than for the Co-containing analogue, due to the presence of less-conducting phases and excessive porosity. In contrast, the relatively high performance of the composite with a nominal nickel content of 3% vol. processed via a two-step approach is related to the specific microstructural features from this sample, including minimal porosity and the presence of the Ca₂Co₂O₅ phase, which partially compensate the complete decomposition of the Ca₃Co₄O₉ matrix. The obtained results demonstrate different pathways to tailor the phase composition of Ca₃Co₄O₉-based materials, with a corresponding impact on the thermoelectric performance, and highlight the necessity of more controllable approaches for the phase composition tuning, including lower amounts and different morphologies of the dispersed metallic phases.