纳米TiO2改性内墙乳胶漆的抗菌性能及甲醛降解研究

为了制备具有空气净化和抑菌功能的环保型内墙涂料,在分析纳米TiO2的光催化原理,铈离子和银离子抑菌机理的基础上,采用锐钛型纳米TiO2载银载铈复合改性纯丙内墙乳胶漆,并对改性后的内墙涂料进行了定性的抑菌环试验、定量的抑菌率试验和甲醛降解试验研究。试验结果表明,纳米TiO2载银载铈复合改性后的内墙涂料具有优异的抗菌性能和甲醛降解能力,经24h后,改性内墙涂料的抑菌率达到99．9％以上,经过40WEt光灯照射8h后甲醛降解率达到75％。     

苹果皮对银离子的吸附行为及其杀菌效果

将苹果皮制备的吸附材料用于负载银离子，所得载银吸附剂用于杀菌，效果显著。考察了溶液pH、苹果皮粉末颗粒量、接触时间、银离子初始浓度和温度等对其吸附银离子的影响。结果表明，pH在5左右时，吸附效果最佳，吸附容量可达到55 mg/g以上。该吸附负载银离子的苹果皮对芽孢杆菌和大肠杆菌都表现出非常优越的杀菌效果。被负载的银是导致杀菌效果的关键成分，纯粹的苹果皮没有任何杀菌效果。     

载银硅酸盐玻璃缓蚀阻垢剂的研究进展

我国冷却水用量占工业用水总量的80%以上,如何实现冷却水节水与零排放对推进工业循环发展至关重要。缓蚀阻垢剂可有效解决冷却水系统的结垢腐蚀问题,提高冷却水的循环利用率。其中,载银硅酸盐玻璃缓蚀阻垢剂是一种缓释型不含磷的多功能水处理剂,同时具备抑菌、阻垢和缓蚀功能,且无二次污染问题,应用前景广阔。本研究重点详述了控释型载银硅酸盐玻璃缓蚀阻垢剂主成分功能及制备方法,总结分析了载银硅酸盐玻璃缓蚀阻垢剂研究现状、现存问题与发展趋势。     

双硫腙聚氨脂泡沫塑料吸附银性能的研究及微量银的测定

本工作研究了负载双硫腙的聚氨酯泡沫塑料对银的吸附性能,并用动态法对经提取银剩下的定影液中银离子定量吸附条件进行了研究,用0.05N硝酸介质乙醇溶液淋洗,可将银离子定量解吸.然后用火焰原子吸收法测定银.从回收率实验可得到令人满意的结果.     

在铜、铅、锌、铁等硫化矿物存在下银的物相分析方法研究

我们在研究硫化铜矿石中银的物相分析方法时发现,含活性硫化铜及高价铁的试料,采用常规化学试剂是很难达到自然银与银的硫化矿物分相测定的目的。试料中含活性硫化铜和高价铁时,若用酸性溶剂浸取银的硫化矿物,铁矿物与酸作用生成的三价铁离子使自然银溶解;若用含氧化剂溶剂浸取自然银,生成的银离子正好是活性硫化铜溶剂,使浸出的银离子转变为硫化铜沉淀。因此,寻找新溶剂是我们的重要课题。本文着重叙述寻找有机新溶剂以解决硫化铜矿石中自然锻的分相测定问题和在前者基础上扩大应用范围,并在铅、锌、铁等硫     

1-吡啶-3-[4-(苯基偶氮)苯基]-三氮烯光度法测定银

研究了在非离子表面活性剂TritonX-100存在下,1-吡啶-3-[4-(苯基偶氮)苯基]-三氮烯(PYPAPT)与银离子反应的条件,建立了测定银的分光光度法.在NaOH碱性介质中,银与PYPAPT反应生成1∶2红棕色络合物,络合物的最大负吸收峰位于530 nm.表观摩尔吸光系数为4.23×104L·mol-1·cm-1,银离子含量在0～2.5 mg/L范围内符合比尔定律.方法用于粗铅矿样中银离子的测定,结果与原子吸收光谱法测定结果一致.     

含银离子杀菌材料进展

含银离子杀菌材料进展西北有色金属研究院张文钲大约一千年前，蒙古牧人就知道用银器皿装马奶可使奶保持不变质。在野外喝水时，只要将银饰或银器浸入水中搅动，水就成了无菌之水。在化学上，银被人们称之为“永久性杀菌剂”。近代科学研究揭示，银离子的杀菌能力特别强，...     

不同介质AAS法测定银精矿中的银

根据银离子能与氯离子、氨离子、硫脲结合形成可溶、稳定的络合物,实验了在不同浓度的盐酸介质、氨水介质、硫脲介质中测定银精矿中的高含量银,其测定范围大于5 000 g/t,确定了AAS法测定高含量银时各介质的最佳浓度范围。经银精矿样品验证及标准物质加标回收实验表明,分析结果准确、可靠,能满足选冶工艺生产的要求。     

科技动态

日本制成世界上最小的立体金属样品近日,日本理化研究所利用红外线成功进行了世界上最小级别的立体状金属加工。研究人员从含有银离子的水溶液中,制作出高度约1/500毫米、具有4只脚的银制品。     

树脂吸附柠檬酸盐-硫代硫酸盐浸出液中的银

铜-柠檬酸盐-硫代硫酸盐溶液是一种具有应用潜力的绿色浸金体系。研究了利用D301离子交换树脂从柠檬酸盐-硫代硫酸盐溶液中吸附银络合物的工艺可行性。考察了溶液pH、柠檬酸盐和硫代硫酸盐浓度及硝酸根对银吸附效果的影响。结果表明,硫代硫酸银络合物树脂吸附为均匀位点的单层吸附,符合准二级吸附动力学。柠檬酸和硝酸根均抑制树脂对硫代硫酸银离子的吸附,当溶液pH大于12时,D301树脂对硫代硫酸银离子的吸附容量急剧降低。研究结果明确了吸附过程的控速步骤及主要影响因素,为进一步实现硫代硫酸盐-柠檬酸溶液中的重贵金属回收提供了理论和技术基础。     

Low Ca2+ dialysate. Effects on bone metabolism in the course of paired filtration dialysis

To evaluate the 1-year effects of PFD performed with low Ca2+ dialysate (1 mmol/l) on calcium metabolism and on bone disease, the authors studied in eight patients who were previously treated with PFD performed with standard Ca2+ dialysate (1.75 mmol/l). On samples from these subjects, the following were evaluated: 1) serum Ca2+ and PO4 levels, 2) serum PTH levels, 3) serum Al levels, and 4) bone morphology. All the patients were hypercalcemic, four with high serum PTH levels (high turnover bone disease, group 1) and four with low serum PTH levels (low turnover bone disease, group 2). In both groups, a decrease in serum Ca2+ and an increase in serum PTH was observed within the third month. In group 2, PTH levels reached the normal range. Because serum Ca2+ levels decreased to normal in both groups, it was possible to administer oral CaCO3 (10.5 +/- 2 g/day) to control serum PO4 and to stop Al gels. This did not induce any increase in serum Ca2+, whereas serum Al fell significantly. In group 1, to prevent a further rise in PTH, patients were treated with intravenous calcitriol (5 +/- 2 micrograms/week). This induced a reduction in the serum PTH without increasing serum Ca2+ or PO4. Within 12 months, an improvement in bone morphology was seen in both groups. It is concluded that the use of low Ca2+ dialysate corrects hypercalcemia in patients with PFD treated with high oral doses of CaCO3, and improves low turnover bone disease. The combination of low Ca2+ dialysate and intravenous calcitriol also improves high turnover bone disease.     

EDTA络合滴定法测定钢渣面脱氧剂中氧化钙和氟化钙

建立了EDAT络合滴定法测定钢渣面脱氧剂中氧化钙和氟化钙含量的分析方法。试样用碳酸钠-硼酸混合熔剂熔融, 稀盐酸浸取, 六次甲基四胺分离铝离子和铁离子后, 以三乙醇胺掩蔽剩余干扰离子, 在强碱介质中, 以钙黄绿素作指示剂, 用EDTA标准滴定溶液滴定了试样中总氧化钙的含量。采用稀乙酸浸取分离试样中碳酸钙、氧化钙, 过滤分离氟化钙, 用锆-二甲酚橙褪色光度法测定了浸取液中的氟, 换算为氟化钙的量;同时用混合酸分解沉淀, 采用EDTA络合滴定法测定了沉淀中氟化钙的量;将二者相加后除以试样总量得到试样中氟化钙的含量。用总氧化钙的含量减去由氟化钙换算成的氧化钙含量, 即为试样中氧化钙的含量。采用方法对钢渣面脱氧剂试样进行6次平行测定, 相对标准偏差(RSD)小于1.5 %。选取高纯铝粉、基准三氧化二铝和基准氧化钙以及萤石标准物质合成钢渣面脱氧剂试样A1、A2、A3, 同时在精炼渣标准物质中加入基准氧化钙和萤石标准物质合成试样A4, 按照方法进行氧化钙和氟化钙的测定, 结果与理论值一致。在钢渣面脱氧剂试样中加入基准氧化钙和萤石标准物质进行加标回收试验, 回收率在94%～102%之间。     

Role of calcium carbonate administration timing in relation to food intake on its efficiency in controlling hyperphosphatemia in patients on maintenance dialysis

A study has claimed that at an equal elemental calcium dose, CaCO3 was not less but equally as efficient in controlling predialysis hyperphosphatemia as calcium acetate, provided both calcium salts were ingested 5 min before meals instead of during meals because the higher acidity of the fasting gastric juice would allow for better dissociation of CaCO3. However, this study did not directly demonstrate that the efficiency of CaCO3 in controlling hyperphosphatemia was actually greater when it was administered before a meal than during a meal. To examine this point, we performed a 3 month randomized crossover trial in 12 reliable and stable patients maintained on chronic hemodialysis. Their plasma concentrations of calcium, protein, phosphate, bicarbonate, urea, and creatinine were measured before the first dialysis of each week and the amount of intact parathyroid hormone (PTH) at the beginning and at the end of each of the 3 months. Comparison of the plasma concentrations measured during the 2 modes of administration showed no significant differences in creatinine, urea, bicarbonate, or intact PTH. The mean (+/-SD) plasma concentration of PO4 was not significantly lower (1.88+/-0.50 vs. 1.74+/-0.41 mM) whereas the corrected level of plasma Ca was significantly lower (2.30+/-0.17 vs. 2.38+/-0.16 mM; p < 0.04) when CaCO3 was given before meals than during meals. In conclusion, the administration of CaCO3 before a meal does not increase its efficiency in controlling hyperphosphatemia because the level of plasma PO4 was actually slightly higher with this timing of administration whereas the comparison of the creatinine and urea levels suggested a stability of phosphate intake and the comparison of the PTH and bicarbonate levels suggested the stability of osteolysis and of the transcellular membrane shift of phosphate. Also, administration of CaCO3 before a meal is associated with significantly lower plasma corrected calcium, suggesting less absorption of calcium, which may be an advantage but only in hypercalcemic patients. There is no reason other than the prevention of its hypercalcemic effect to recommend the administration of CaCO3 just before meals rather than during meals.     

Feasibility study of a natural crosslinking reagent for biological tissue fixation

The hardening properties of calcium phosphate cements in the CaHPO4-alpha-Ca3(PO4)2 (DCP-alpha-TCP) system have been investigated with interest focused on the compressive strength and microstructure development. Previous studies have shown that the addition of CaCO3(CC) leads to a modification of the calcium-deficient apatite structure of the reaction product, which results in a material more similar to the apatite in bone mineral. The addition of 10% w/w of CC to the initial DCP-alpha-TCP powder mixture resulted, with time, in a retardation of the development of compressive strength. However, the optimum compressive strength reached values up to 40% higher than CC-free samples. This retarding effect also has been monitored as a function of the calcium to phosphorus (Ca/P) ratio of the DCP and alpha-TCP mixture, showing the importance of the final cement properties of the relative quantities of the reactants in the mixture.     

Osteoid osteoma of the proximal humerus: two misleading cases

OBJECTIVES: To investigate how often the ED ordering of stat serum calcium (Ca+2), magnesium (Mg+2), and phosphorus (PO4(-3)) levels affected clinical treatment; to define the diagnoses of patients for whom Ca+2, Mg+2, and PO4(-3) measurements did affect clinical therapy; and to suggest guidelines for more appropriate ordering of these laboratory tests. METHODS: A retrospective chart review was performed in an academic teaching hospital. All adult ED patients who had Ca+2, Mg+2, or PO4(-3) laboratory testing during the 9-month study period were included and evaluated for potential clinical impact of an abnormal Ca+2, Mg+2, or PO4(-3) laboratory test. RESULTS: 1.477 patients had Ca+2, Mg+2, or PO4(-3) measured while in the ED during the study period. Of these, 260 patients (17.6%) had a total of 312 abnormal Ca+2, Mg+2, or PO4(-3) values as defined by results exceeding +/- 15% of normal reference values. Of these, only 5 patients (0.3%) received treatment for abnormal values in the ED, while 75 patients (5.1%) were treated once admitted to the hospital. In this study, the only diagnostic groups to whom significant treatment was administered were diabetic patients (Ca+2 and PO4(-3); alcoholic patients (Mg+2); and renal failure patients (Ca+2, Mg+2, and PO4(-3). CONCLUSION: These results suggest that stat Ca+2, Mg+2, and PO4(-3) levels seldom affect clinical treatment in the ED. The frequency of ordering these tests may be reduced by obtaining Ca+2, Mg+2, or PO4(-3) measurements only for patients known to be at risk for such abnormalities, based on their existing or suspected diagnoses. The authors suggest obtaining these tests, when indicated, on a "non-stat" basis, with the subsequent laboratory results becoming available in-hospital, where treatment is more likely to occur.     

氧化钙类杂质对铁水脱磷的影响分析

摘要：除尘灰制备炼钢脱磷剂极具实用价值,但其所含CaO类杂质却会影响脱磷。1400℃条件下,参考Fe2O3-CaO-CaCl2系脱磷剂,分别利用不同摩尔比的Ca(OH)2、CaCO3替换脱磷剂中的CaO,对磷质量分数为0.3%的铁水进行了脱磷试验。同时,分别利用CaO、Ca(OH)2、CaCO3作为固定剂,研究了各自的铁水脱磷特征。此外,参考Fe2O3-CaO-SiO2-CaCl2系脱磷剂,分别利用CaO/SiO2混合物、CaSiO3作为脱磷剂初始组分,研究了二者的脱磷差异。结果表明：当Ca(OH)2以任意摩尔比替换脱磷剂中的CaO时,替换比对脱磷率的影响并不明显;但当使用CaCO3进行替换时,脱磷率会在替换比超过约05后显著下降。而相对于CaO,当以Ca(OH)2、CaCO3作为固定剂时,脱磷速率能在初期获得明显提高,但在后期相对下降。此外,相对于CaO/SiO2混合物,当以CaSiO3作为脱磷剂初始组分时,脱磷速率在前期和后期均能获得明显提高。     

Effect of hydroxyapatite microcrystals on macrophage activity

Hydroxyapatite (HAp) microcrystals were synthesized by a neutralization reaction of Ca(OH)2 suspension and H3PO4 solution using an ultrasonic homogenizer. The in vitro interaction of HAp microcrystals with rat peritoneal macrophages was investigated by measuring the viability, acid phosphatase (ACP) activity, lactate dehydrogenase (LDH) activity and intracellular calcium content. HAp calcined at 800 degrees C and alpha-alumina particles (alumina) were used as comparative materials. Macrophages actively phagocytosed HAp microcrystals by dissolving them. However, no damage in macrophages exposed to HAp microcrystals was observed by transmission electron microscopy. Macrophages in the presence of HAp microcrystals showed less ACP and LDH activity and higher intracellular calcium content than those in the presence of calcined HAp and alumina. HAp microcrystals had excellent biocompatibility to macrophages as well as sintered HAp.     

聚丙烯酸复合阻垢剂的合成,性能及机理分析

讨论了聚丙烯酸复合阻垢液的合成和性能测试，说明该阻垢液对ＣａＣＯ３、Ｃａ３（ＰＯ４）２均具有很好的阻垢能力，并分析其机理．     

In Situ Laser Coating of Calcium Phosphate on TC4 Surface for Enhancing Bioactivity

 Titanium alloy has been a successful implant material owing to its excellent ratio of strength to weight, toughness, and bio inert oxide surface. Significant progress has been made in improving the bioactivity of titanium alloy by coating its oxide surface with calcium phosphates. In the present study, in situ coating was reported on Ti6Al4V(TC4) surface with calcium phosphate (Ca P) bioceramics synthesized and synchronously cladded by laser beam. This coating was grown by first preplacing directly the raw powders, which contain 80% of CaHPO4·2H2O, 20% of CaCO3, and dram of rare earth (RE), on the TC4 surfaces, and then exposing the surfaces to the laser beam with a power density of 1273-1527 MW·m-2 and a scanning velocity of 105 m/s. The resultant coating was characterized using scanning electron microscopy (SEM), X ray diffraction (XRD), thermogravimetric analysis and Different thermal Scanning (TG DSC), and Energy Dispersive X ray Detection (EDX). The results show that these laser ceramics include hydroxyapatite (HA), tricalcium phosphate (TCP), Ca2P2O7, and other Ca P phases, and the interface between the coating and the TC4 substrate has tighter fixation, in which the chemical bonding is approved. These laser hybrid coatings are useful in enhancing the bioactivity of titanium alloy surfaces.     

Alkoxide route for preparing hydroxyapatite and its coatings

The preparation of hydroxyapatite using n-butanol or ethanol solutions of P2O5 and Ca glycoxide as precursors of P and Ca was investigated by nuclear magnetic resonance (NMR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Stable mixed solutions of the precursors could be obtained in the presence of acetic acid (HOAC). For the mixed solution of Ca glycoxide with the ethanol solution of P2O5, a lower HOAC/Ca ratio was needed since the ethanol solution of P2O5 contained a lower concentration of H3PO4, a species that easily forms precipitates in the presence of the Ca containing species. An amorphous powder was obtained by heating the stable solution of Ca glycoxide and PO(OH)x(OEt)3-x with an HOAC/Ca ratio of 4 in a hot plate at approximately 150 degrees C. Hydroxyapatite (HAP) was directly formed after calcining the amorphous powder at 500 degrees C. The stable mixed solutions of Ca glycoxide and the alcoholic solutions of P2O5 were used to prepare HAP coatings on alumina substrates using a dip-coating method. The resulting ceramic coatings have a rough surface and an adhesion strength of about 10 MPa. The morphology of the coatings is dependent on the preparation chemistry.