口腔内金属修复物与磁共振伪影的关系

金属与合金作为口腔修复材料,在口腔临床中应用非常广泛。但在进行口腔颌面部和脑部磁共振检查时,口内某些金属修复物可使图像上出现伪影,干扰正常解剖结构和病变组织的显示。本文就口腔金属修复物与磁共振伪影相互关系的研究进展作一综述。

口腔内金属修复物的成分分析

目的:测定口腔内金属修复物的成分,确定使用的合金种类,以使牙科金属过敏患者避免再次使用此种合金。方法:用细砂纸及圆锥形抛光磨头,采取微量口腔内金属修复物,通过EDXRF(荧光X线分析仪)测定所含金属成分,确定合金种类。结果:14例可疑牙科金属过敏患者中,牙科金属修复物120个,按照检出频度的高低,排在前10位的金属元素分别是Ag、Cu、Au、Pd、Zn、Sn、Co、Cr、In和Mo。Au-Ag-Pd合金的使用频度为65%,Ag-Sn-Hg合金为2.5%,Ag合金为5.4%,Au合金为14.6%,Ni-Cr、Co-Cr合金为10.1%,其他2.4%。2种以上异种合金共存同一口腔环境中的患者12例,5种合金同时存在者1例。含Hg的银汞合金的使用频度为2.5%,与10年前的使用频度16%相比下降明显。Ni、Cr、Co的使用频度未见明显改变。结论:被疑牙科金属过敏的患者中,异种金属同存的现象严重,提示在口腔科临床工作中,尽量避免使用异种金属及含Hg和Ni等易诱发过敏的金属合金。

伤骨再生汤辅助双切口金属植入物内固定修复治疗SchatzkerⅤ、Ⅵ型胫骨平台双髁骨折患者的效果

目的:分析SchatzkerⅤ、Ⅵ型胫骨平台双髁骨折患者采用伤骨再生汤辅助双切口金属植入物内固定修复治疗的价值。方法:选择2019年2月—2021年2月我院收治80例Schatzker V、Ⅵ型胫骨平台双髁骨折患者作为研究对象,分为对照组(n=40,采用双切口金属植入物内固定修复治疗)、观察组(n=40,在对照组基础上辅助展开伤骨再生汤治疗),统计两组临床疗效、临床指标、骨转换生化标志物、并发症、患者满意度、炎症因子水平、预后效果。结果:观察组总有效率为95.00%,高于对照组的77.50%(P<0.05);观察组膝关节功能、放射学评分高于对照组(P<0.05);观察组并发症发生率为2.50%,低于对照组的17.50%(P<0.05);观察组患者满意度高于对照组(P<0.05);观察组CTX、PINP低于对照组(P<0.05);观察组IL-1β、IL-6、IL-22低于对照组,IL-4、IL-13、sTNF-RI高于对照组(P<0.05);观察组预后效果优于对照组(P<0.05)。结论:伤骨再生汤辅助双切口金属植入物内固定修复在SchatzkerⅤ、Ⅵ型胫骨平台双髁骨折治疗中可行性较高,既可改善其关节功能及预后效果,亦可降低并发症率,同时治疗后骨转换生化标志物、炎症因子指标得到控制,且患者对本次诊疗服务满意度较高。

Research on Phytoremediation of Heavy Metal Pollution in River Sediment by Medicago sativa L.

[Objective] The aim was to study the phytoremediation of heavy metal pollution in river sediment by Medicago sativa L.,so as to provide reliable references for the phytoremediation of heavy metal pollution in river sediment.[Method] The air-dried,screened and mixed sediment was put in rectangular PVC box（0.6 m×0.5 m×0.4 m） with seepage vent at the bottom,and the water holding capacity（WHC） of sediment was kept at 30%-60% by deionized water.The seeds of Medicago sativa L.were sown in April 2010,and seedlings were thinned after 7 d.Samples were collected from rhizosphere soil every 30 d,and were used to determine the content of heavy metals,bacteria quantity and enzyme activity in sediment.In addition,the accumulation of heavy metals in the roots,stems and leaves of plant was measured after harvest in October.[Result] Different parts of Medicago sativa L.varied in accumulation capacity to different heavy metals.The accumulation amount of Zn in Medicago sativa L.was the highest,especially in roots.Meanwhile,the accumulation amount of heavy metals like Ni,Cr,Cu and Pb in roots was higher than that of stems and leaves.In contrast,Mn was mainly accumulated in leaves and its amount accounted for 42.47% of the total amount in plant.Besides,the accumulation amount of all heavy metals was the lowest in stems.Ni,Cr,Cu and Pb could be degraded more effectively than Mn,and increasing the planting time and sowing times of crop was beneficial to the degradation of heavy metals.After planted Medicago sativa L.,the quantity of microorganisms in sediment went up obviously,and dehydrogenase activity also showed an increaseing trend.[Conclusion] Medicago sativa L.has certain restoring effect on Zn,Ni,Cr,Cu and Pb,and could be used to restore heavy metal pollution in river sediment.

Research Progress of Phytoremediation Technology on Soils Polluted by Heavy Metals in Mining Areas

Phytoremediation is an efficient and economic ecological technology. It includes phytostabilization, phytovolatilization, and plant absorption. In the research, status quo and progress of Phytostabilization and plant absorption in soils polluted with heavy metals in metal mines were summarized, including the characteristics and status quo of phytoremediation and selection method of hyperaccumulator. In addition, further research was proposed as well.

Advances in Microbial Remediation on the Application of Heavy Metal Pollution in Agricultural Water Resources

Heavy metal pollution in agricultural water resources is very serious in re- cent years, resulting in large losses of the agricultural economy and endangering human life and health. Due to the advantages of low cost, high efficiency and less secondary pollution, microbial ramediation technology is widely used in the treatment of heavy metal pollution in agricultural water resources. At present, with the progress of modern biotechnology, microbial remediation of heavy metals in agricul- tural water resources has grown rapidly. The sources and status quo of heavy met- al pollution in agricultural water resources at home and aboard, and the principles of microbial remediation of heavy metals pollution in agricultural water resources were reviewed in this paper, as well as the several common microbial remediation technology of heavy metals in agricultural water resources. Additionally, the further research work of heavy metal contaminated agricultural water resources by microbial ramediation were prospected.

Microbial Remediation of Heavy Metal(loid)Contaminated Soil: A Review

Because of the rapid development of industrial processes, increased urban pollution and agricultural chemicals applied in recent years, heavy metal(loid) pollution in soil has been very serious, and there is an urgent need for fast and efficient removal of heavy metal(loid) pollution. Currently, environmental microorganisms are always used to perform biological alteration or improvement of soils and sewage. Using functional microorganisms that are resistant to toxic heavy metal(loid) ions for alteration and transformation of heavy metal(loid)s in ionic form is an effective measure for microbial remediation of heavy metal(loid)contaminated soil. This paper reviewed the microbial remediation mechanism of heavy metal(loid) contaminated soils, and the approaches for breeding bacteria those can be used for highly efficient removal of heavy metal(loid)s, as well as the application examples of microbial remediation and transformation of heavy metal(loid) contaminated soil, and finally described the future trends and further research work of heavy metal(loid) contaminated soils by microbial remediation.

Use of Sorghum Crops for in Situ Phytoremediation of Polluted Soils

There has been carried out a comparative research, which allow us to determine the quantities and the central points of accumulation ofPb, Cu, Zn and Cd in the vegetative and reproductive organs of the four sorghum varieties （technical sorghtan, sugar sorghum, sudan grass and grain sorghnm）, as well as to ascertain the possibilities for their growth in soils contaminated with heavy metals and their application for phytoremediation purposes. The experimental plots were situated at different distances （0.1 and 15.0 kin） from the source of pollution-the Non-Ferrous Metal Works near Plovdiv, Bulgaria. On reaching commercial ripeness, the crops were gathered and the concentrations of Pb, Cu, Zn and Cd in their different parts-roots, stems, leaves and gains-were determined through dry mineralization. To determine the heavy metal content in the samples, ICP was used. A clearly distinguished trend exists which describes the accumulation of heavy metals within the vegetative and reproductive organs of the studied crops. Sudan grass and technical sorghum accumulated larger heavy metal quantities compared to sugar sorghum and grain sorghum, as the majority of the heavy metals was retained by the roots and a very small amount was translocated to epigeous parts. The depots for accumulation were in the following order： roots 〉 leaves 〉 stems 〉 grains. The studied crops can be related to metal-tolerant crops and can be cultivated on softs which are of low, medium or high contamination with lead, zinc and cadmium, as they do not exhibit a tendency of accumulating these elements in grains at levels above the maximum permissible concentrations for fodder. The selective accumulation of Pb, Cu, Zn and Cd in the roots and the possibility to remove the root-remains makes technical sorghum, sugar sorghum and Sudan grass extremely suitable for phytoremediation purposes. The possible use of grains for animal food guarantees the economic expedience upon the selection of these crops.

Fungal Absorption and Tolerance of Heavy Metals

Soil, water, sediments and air are frequently contaminated with heavy metals. In Saudi Arabia, heavy metals contamination may result from petroleum and mining operations, refining ores, sludge, waste treatment, electrical equipment, paints, alloys, pesticides, batteries and fuel transportation. Microbial processes lead to appreciable and even complete remediation of heavy metals contaminated environments. The chief ways, by which such remediation may be accomplished, include biosorption, bioaugmentation, bioventing, biostimulation, bioaccumulation, biosolubilization, bioreduction, bioprecipitation, mineralization and methylation. Other technologies and methods are fully developed and now are being used in practice, such as heavy metals nanotechnology bioremediation. An area of fungal biotechnology currently in vogue is the use of fungal biornass to absorb metal ions from contaminated solutions. Such biological approaches of metal ions recovery can be used to clean up polluted effluents or to recover precious metal ions from solutions. The present review provides information on fungal bioremediation of heavy metal contamination for use in future studies in Saudi Arabia as well as in the Arabian Gulf Region.

Photocatalytic remediation of ionic pollutant

Recently, the photocatalysts have attracted lots of attention and efforts due to their great potential for environmental remediation application. Toxic ions in water are an increasing environmental pollutant with the fast development. Numerous researches have been made to develop photocatalysts to treat ionic pollutants under the illumination of ultraviolet light and visible light. Here, photocatalytic remediation of toxic ionic pollutants has been reviewed. This review summarized and discussed various photocatalysts including TiO〉 modified TiO2, metal oxides, metalsulfides, and nitrides and their recent progress in removing ionic pollutants such as heavy metal ion. The latest achievements and their future prospects of photocatalytic remediation of ion pollutant have also been reviewed.

Effects of Double Harvesting on Heavy Metal Uptake by Six Forage Species and the Potential for Phytoextraction in Field

The pollution of soils by heavy metals has dramatically increased in recent decades. Phytoextraction is a technology that extracts elements from polluted soils using hyperaccumulator plants. The selection of appropriate plant materials is an important factor for successful phytoextraction in field. A field study was conducted to compare the efficiency of six high-biomass forage species in their phytoextraction of heavy metals(Cd, Pb, and Zn) from contaminated soil under two harvesting strategies(double harvesting or single harvesting). Among the tested plants, amaranth accumulated the greatest amounts of Cd and Zn, whereas Rumex K^(-1) had the highest amount of Pb in the shoot under both double and single harvesting. Furthermore, double harvesting significantly increased the shoot biomass of amaranth, sweet sorghum and sudangrass and resulted in higher heavy metal contents in the shoot. Under double harvesting, the total amounts of extracted Cd, Pb and Zn(i.e., in the first plus second crops) for amaranth were 945, 2 650 and 12 400 g ha^(-1), respectively, the highest recorded among the six plant species. The present results indicate that amaranth has great potential for the phytoextraction of Cd from contaminated soils. In addition, the double harvesting method is likely to increase phytoextraction efficiency in practice.

Factors Affecting Phytoextraction： A Review

Hyperaccumulators concentrate trace metals and heavy metals in their shoots when grown in metal-contaminated soils and these trace metal-loaded plants may be removed by harvesting the fields. Studies exploring the beneficial role of these hyperaccumulators to clean up the environment have led to the development of phytoextraction. The success of phytoextraction depends upon the high biomass of plant species and bioavailability of metals for plant uptake. The phytoavailability of metals is influenced by soil- associated factors, such as pH, redox potential, cation exchange capacity, soil type, and soil texture, and by plant-associated factors, such as root exudates and root rhizosphere processes （microorganisms）. Efficiency of phytoextraction can be improved by advanced agronomic practices including soil and crop management by application of genetic engineering to enhance the metal tolerance, shoot translocation, accumulation, and sequestration and by application of chelate treatments to enhance metal bioavailability. Application of microorganisms including bacteria and mycorrhiza may facilitate the phytoextraction application at commercially large scale.