Sintered carbonate apatites as bioresorbable bone substitutes

The dissolution behavior of sintered carbonate apatite was investigated in a 10 mM/L acetic acid solution adjusted to pH 5.0 at 37 degrees C, and compared to that of sintered hydroxyapatite and bone apatite for the purpose of establishing some similarities between the physicochemical dissolution of apatite biomaterials in vitro and their ability to be resorbed by osteoclasts in vivo. Both the sintered carbonate apatite and the bone apatite dissolved to an appreciable extent. Their solution compositions changed in an almost identical manner until toward the end of the reaction. The solution compositions for sintered carbonate apatite at 30 s was comparable with that for sintered hydroxyapatite at 3.8 days with respect to the degree of supersaturation, indicating that the former specimen is much more soluble than the latter specimen. Osteoclasts which were obtained from the long bones of 1-day-old neonatal rabbits resorbed bone and sintered carbonate apatite, but not sintered hydroxyapatite. These findings suggest that sintered carbonate apatites, which have characteristics that can be favorably compared with those of bone, especially with respect to its reactivity to acid media, would be useful as bioresorbable bone substitutes.     

煤基磁性活性炭的制备

以大同烟煤为原料、Fe₃O₄作为添加剂,催化制备了煤基磁性活性炭(MCAC).利用氮气吸附等温线表征了MCAC的孔隙结构,并考察了其吸附性能(碘值、亚甲兰值)和磁学性能.结果表明,Fe₃O₄对MCAC孔隙的产生具有催化作用,有利于活性炭中孔的形成和发育.其中添加10% Fe₃O₄的MCAC中孔率高达76.0%.MCAC与普通活性炭(AC-0)相比,碘吸附值明显降低,而亚甲兰吸附值显著提高.添加7% Fe₃O₄的MCAC,其碘值降低了25.5%,亚甲兰值提高了79.9%.添加适量的Fe₃O₄制备的MCAC具有较高的比饱和磁化强度和磁导率.Fe₃O₄质量分数为4%和10%时,所得MCAC的比饱和磁化强度分别是AC-0的24.4倍和44.5倍.     

以干熄焦粉尘为原料制备活性炭的研究

随着环保意识的增强和炼焦技术的发展,国内大型焦化厂陆续采用干熄焦技术处理焦炭,由于干熄焦技术的推广应用,焦化厂每天将产生大量的干熄焦粉尘.文章以焦化企业生产过程中的废弃物--干熄焦粉尘为原料经化学方法活化,制备出了吸附性能较好的活性炭.     

The development of hemoglobin solutions as red cell substitutes

It is clear from the trials described here that the number of different products being tested and the potential variation between batches of the same product present major problems in evaluating the safety and efficacy of hemoglobin-based oxygen carriers. The recent CBER "Points to Consider" document [42] makes clear that an understanding of the safety of oxygen carriers in humans is of paramount importance. In the event of phase II or indeed phase III trials being approved, the need may still remain for additional phase I or preclinical studies, particularly as unwanted or toxic properties of the solutions affect efficacy. It is likely that demonstrating safety and efficacy in acute hemorrhagic shock will be the most difficult task, as this is a complex clinical indication and is often accompanied by multisystem damage. The use of a hemoglobin-based oxygen carrier in this setting must have a distinct advantage over a plasma expander alone. In the application of perioperative transfusion, a decreased requirement for red cell transfusion has already been accepted as a basis for the efficacy for erythropoietin. However, in the case of a hemoglobin-based oxygen carrier, the reduction of red cell requirement in perioperative procedures would need to be balanced against any adverse drug reactions or unacceptable hemodynamic effects that may be caused by the product. It appears that there are still numerous hurdles to overcome in the development of hemoglobin-based red cell substitutes. Before these products can become established in medical practice, it is imperative that the potential mechanisms of toxicity of cell-free hemoglobin are clearly understood. Approval of hemoglobin-based oxygen carriers for clinical use will depend not only on clear demonstration of both safety and efficacy but also on risk-versus-benefit issues. Our understanding of the physiological effects of these products will evolve as progress is made in their clinical evaluation.     

Reduced engraftment and wound closure of cryopreserved cultured skin substitutes grafted to athymic mice

A simulation model was developed to test the accuracy of indirect estimates of maternal mortality (the sisterhood method). The model generated a first generation of grandmothers, a second generation of mothers (with brothers and sisters), and a third generation of children (births). In the second generation, maternal mortality was introduced. Empirical values for the parameters of fertility and mortality were taken from a prospective survey in Senegal (Niakhar). Results based on 100 simulations of the same situation revealed several limitations of the sisterhood method: The indirect estimates could fall as far as 33 percent from the true values on individual cases; the indirect estimates tended to be systematically higher than the direct estimates; their range was wider, as were their confidence intervals; and biases were particularly strong for the younger age groups of respondents. Reasons for these biases are explored.     

Fibrogenic potentials of coal slags used as abrasive blasting substitutes

This study was designed to examine the fibrogenic potentials of four coal slags that are being used as substitutes for silica sand in abrasive blasting. Six groups of 100 male Sprague-Dawley rats, including four coal slag groups, a vehicle control, and a positive control for fibrosis (Minusil quartz), were used. Each dust treatment group was given a single 40-mg dose of test agent via intratracheal instillation. Interim sacrifices of 15 animals per group were performed at 2 d, 3 mo, and 6 mo posttreatment, with the terminal sacrifice conducted at 12 mo. Hematoxylin and eosin stained histologic sections were prepared from designated formalin-fixed tissues collected at each necropsy and examined microscopically. Pulmonary silicon analyses were performed for each group at the 2-d and 12-mo sacrifices. Pulmonary function analyses were conducted for each group at the 3-, 6-, and 12-mo sacrifices. Lung hydroxyproline analyses were conducted for 15 animals in each group at the terminal sacrifice. The pulmonary fibrogenic potentials of the four coal slag groups were compared histologically with the Minusil and vehicle controls. A mild to moderate interstitial fibrosis, which was progressive with time, was noted in each of the coal slag groups. However, the coal slag-induced lung fibrosis was much less than that produced by Minusil. Differences in fibrosis among the individual coal slags were relatively minor and certainly not as striking as those between the slags and Minusil. Other data derived from this study, such as lung hydroxyproline content, pulmonary particulate burdens, pulmonary function, and animal body weights, provided further evidence of a reduced toxicity for the coal slags compared to Minusil.     

提金用活性炭性能测定及选优

炭浆法(CIP或CIL) 提金工艺活性炭的性能及其测定方法、性能间的关系以及怎样选择适宜于炭浆法的活性炭做了粗浅探讨。对国内外活性炭评价标准进行了分析,提出了炭浆法提金用活性炭的性能测定方法及参数值。     

活性炭选择性催化还原NOx

采用活性炭作催化剂,NH3为还原剂,进行活性炭脱硝机理的实验研究.分别考察了烟气组分、温度、活性炭的比表面积及不同材质对NOx去除率的影响.结果表明:活性炭作为单纯的吸附剂,其NO吸附容量较小,O2的加入使吸附容量增大,NH3与O2同时存在则可达到最佳去除效果,H2O的存在不利于活性炭的催化作用;温度在200℃时,活性炭催化活性达到低谷;煤质活性炭催化效果优于木质;在一定范围内,比表面积的增大有利于催化活性的提高.利用SEM对所用不同样品进行扫描,进一步分析活性炭表面结构对吸附催化效果的影响.     

Adsorption of carbon dioxide by coconut activated carbon modified with Cu/Ce

A series of the coconut activated carbons (CAC) based absorbents modified with Cu and Ce (Cu/CAC, Cu/Ce/CAC) were prepared by impregnation technology for carbon dioxide capture. The adsocrption equilibriums of CO₂ on Cu/CAC and Cu/Ce/CAC were measured. The results showed that the adsorption capacity of CO₂ onto the activated carbon modified with Cu/Ce increased with the decreasing temperature in the same pressure. The adsorption capacity of CO₂ on Cu/CAC was higher than that of the blank CAC, and compared with the Cu/CAC, the adsorption capacity of CO₂ of Cu/Ce/CAC with the mass ratio of Cu/Ce=30 was improved at 298 and 303 K. In addition, the adsorption equilibrium data for CO₂ at various temperatures was fitted to Langmuir, Freundlich and D-R isotherm models. It was found that the D-R equation was the best model for fitting the adsorption data on Cu/Ce/CAC at different temperatures.     

Adsorption of carbon dioxide by coconut activated carbon modified with Cu/Ce

A series of the coconut activated carbons(CAC) based absorbents modified with Cu and Ce(Cu/CAC,Cu/Ce/CAC) were prepared by impregnation technology for carbon dioxide capture.The adsocrption equilibriums of CO2 on Cu/CAC and Cu/Ce/CAC were measured.The results showed that the adsorption capacity of CO2 onto the activated carbon modified with Cu/Ce increased with the decreasing temperature in the same pressure.The adsorption capacity of CO2 on Cu/CAC was higher than that of the blank CAC,and compared with the Cu/CAC,the adsorption capacity of CO2 of Cu/Ce/CAC with the mass ratio of Cu/Ce=30 was improved at 298 and 303 K.In addition,the adsorption equilibrium data for CO2 at various temperatures was fitted to Langmuir,Freundlich and D-R isotherm models.It was found that the D-R equation was the best model for fitting the adsorption data on Cu/Ce/CAC at different temperatures.     

活性炭富集碘量法测定金的探讨

对活性炭富集碘量法测定金进行了实际测定试验的探讨，确定了各步骤最佳分析条件，使该方法更易于掌握，且节约了成本。     

Adsorption of gold on activated carbon in bromide solutions

Adsorption of gold on activated carbon from gold bromide solutions was examined as a function of pH, particle size, amount of carbon, initial gold bromide concentration, bromine concentration, temperature, and various cations and anions. The pH did not have any effect on gold adsorption below pH = 6. Above pH = 6, pH had a dramatically negative effect. The adsorption occurred according to a first-order reaction-rate model. The reaction-rate constant was proportional to the inverse of carbon particle radius, the amount of carbon, and independent of the initial gold concentration. Temperature had very little effect on the rate of gold adsorption. Cations (Cu²⁺, Fe³⁺, Ca²⁺, Mg²⁺, and Na⁺) and anions (SO ₄ ² , Cl^-, Br^-) did not have any effect on gold adsorption. Free bromine had a very negative effect on gold uptake. Gold bromide is very stable and stays in this form on the carbon surface. Contrary to this, gold chloride is unstable, and elemental gold precipitates on the carbon surface. Loading capacity of carbon depended on the presence of free bromine. In the presence of free bromine, it was further dependent on temperature (increased with increasing temperature). AtT = 25 °C, gold loading was 27 to 64 kg Au/t carbon. In bromine-free solutions, gold loading was 174 to 315 kg Au/t carbon.     

以焦油渣为原料制备高比表面积的活性炭

以焦化企业生产过程中的废弃物——焦油渣为原料生产目前及今后需求量极大的活性炭。以焦油渣为原料制备出了高比表面积活性炭，而且采用不同的工艺参数生产出吸附性能和用途不同的活性炭，证明可以通过控制工艺参数来控制活性炭的吸附性能。     

The mechanism of adsorption of aurocyanide onto activated carbon

The mechanism of adsorption of aurocyanide onto activated carbon and its subsequent élution are examined in this study, with special reference to the effects of acid and alkali treatment on the system. The results, including a careful analysis of the distribution of all ions in the ad-sorption and elution processes, are discussed, and evidence for the adsorption and elution mech-anisms involved is presented. It is proposed that, under normal plant conditions, aurocyanide is extracted onto activated carbon in the form of an ion pair, Mⁿ+[Au(CN)₂]ⁿ], and eluted by hydroxide or cyanide. The hydroxide or cyanide ions react with the carbon surface, rendering it relatively hydrophilic with a decreased affinity for neutral species. Additional adsorption mechanisms are shown to operate under other conditions of ionic strength, pH, and temperature, and it is suggested that this may account in part for the lack of agreement among workers.     

诺芮特柱状活性炭在黄金生产中的应用

介绍了荷兰诺芮特公司生产的柱状活性炭主要性能及在黄金生产中的应用效果,并与通用的粒状活性炭进行了比较.在保证吸附金速度和吸附容量前提下,诺芮特柱状活性炭因硬度高,可减少在吸附过程中因活性炭磨损产生的粉炭吸附而带走的黄金,减少黄金的流失,提高企业经济效益.     

半焦制备活性炭的新工艺

摘要：基于煤基直接还原过程,以半焦为原料,利用铁矿预热氧化球团还原产生的气体为活化剂,开发一步法炭化、活化制备高性能活性炭新工艺,并通过优化制备温度、制备时间及还原剂用量等工艺参数,可同时得到优质还原球团。结果表明：在制备温度850℃、时间1h,半焦/球团的质量比为1∶1～4∶1的条件下,活性炭产率大于67%,耐磨强度达90%以上,比表面积和碘吸附值分别高于330m2/g、500mg/g,远优于商品活性炭,同时可得到金属化率为85%以上的预还原球团。     

活性炭吸附金的初步研究

本文介绍美国研究活性炭从矿浆中吸附金的方法和设备,以及我们采用该方法所取得的研究成果。其中包括活性炭的种类及其用量的确定;金的吸附速率和金的平衡吸附曲线;以及炭浆法和炭浸法的比较。     

活性炭催化臭氧化处理含氰废水的试验研究

研究了活性炭催化臭氧化降解低质量浓度含氰废水,考察了臭氧投加量、活性炭用量、pH值等因素对处理效果的影响.试验结果表明:活性炭对臭氧有明显的催化作用,并可以提高臭氧的利用率;在CN-初始质量浓度150 mg/L、臭氧投加量30 mg/min、活性炭14 g/L、反应30 min条件下,CN-去除率为99.8%,相对于单...