内含解毒塔的不对称框架结构解毒房的定向爆破拆除?

以沈阳铬渣无害化处理厂解毒房爆破拆除为工程实例,研究内含解毒塔的不对称框架结构的解毒房的定向拆除爆破。根据实际工程设计模拟方案,针对不同爆高和不同延期时间,采用LS-DYNA软件进行4种爆破方案的模拟,经对比分析,得出最佳的爆破方案。分析解毒塔下落过程可知,最后一排立柱起爆的时间要小于整体形成有效倾角的时间,同时也要小于解毒塔的落地时间,起爆时间与爆高是解毒房顺利倒塌的关键。理论计算解毒房倒塌转角随时间的变化,与模拟较为符合;实际倒塌转角随时间的变化与模拟过程更为接近,采用LS-DYNA软件可以较好地模拟爆破拆除过程。     

Improvement of minimum paint film thickness for THz paint meters by multiple-regression analysis

We propose a numerical parameter fitting method to determine the time delay between two temporally overlapped echo pulses in terahertz (THz) tomography measurements. The method is based on multiple-regression analysis with the least-squares method and is applied to decrease the minimum paint film thickness for THz paint meters. Applying multiple-regression analysis to paint thickness measurements is five times more sensitive with regard to the minimum thickness than numerical Fourier deconvolution. We apply the proposed method to determine the optical thickness, geometrical thickness, and group refractive index of dry paint film and wet paint film. The proposed method is useful for decreasing the minimum thickness for a THz paint meter and other THz tomography measurements.     

Endothelial cell cultures as a tool in biomaterial research

Progress in biocompatibility and tissue engineering would today be inconceivable without the aid of in vitro techniques. Endothelial cell cultures represent a valuable tool not just in haemocompatibility testing, but also in the concept of designing hybrid organs. In the past endothelial cells (EC) have frequently been used in cytotoxicity testing of materials, especially polymers, used in blood-contacting implants, as well as for investigating seeding technologies for vascular prostheses. At present the exponential development both in theory and practice of cell and molecular biology of the endothelium offers great promise in the biomaterial field. Up until now this EC research field has mostly been non-biomaterial orientated. Nevertheless, the relevance for biomaterial research is apparent. Four aspects will be concisely reviewed under the headings inflammation, with special reference to cell adhesion molecules (CAMs) and cytokines, angiogenesis, focusing on the healing response, signal transduction, presenting examples from cytokine- and metal ion-induced up-regulation of genes coding for CAMs, and, finally, endothelial functionality, with emphasis on the principal characteristics of the physiological endothelial phenotype. Finally, the application of these fields to three foci of biomaterial research will be discussed, emphasizing the role of EC culture techniques in controlling the host response to biomaterials (microvascular EC), controlling EC functionality (promoting positive effects and down-regulating negative effects), and tissue engineering (integration of EC into hybrid organs/biosensors). The need for more co-culture and three-dimensional models will be stressed and data from the authors’ laboratory presented to illustrate these principles. © 1999 Kluwer Academic Publishers     

Detoxification of Tunisian landfill leachates by selected fungi

Young landfill leachates (LFL) collected from Djebel Chekir (Tunisia) discharge area were found to be highly loaded with organic matter, ammonia, salts, heavy metals, phenols and hydrocarbons. Despite the possibility of their biodegradability, they represent a threat to the environment and show some resistance to conventional wastewater treatment processes. For these reasons, this study attempted to develop a biological process for the treatment of LFL using selected strains of Trametes trogii, Phanerochaete chrysosporium, Lentinus tigrinus and Aspergillus niger. Experiments were undertaken at different concentrations of the effluent up to 100%. COD removal efficiencies for P. chrysosporium, T. trogii and L. tigrinus were of 68, 79 and 90%, respectively, when LFL underwent a two-fold dilution. COD abatements were accompanied with an important enzyme secretion and a high reduction in the toxicity, expressed as percent bioluminescence inhibition (%BI < 20%). Above 50% of LFL, the effluent was toxic to these strains and caused growth inhibition indicating the sensitivity of these strains to concentrated LFL. Comparatively to the other tested strains, A. niger showed to tolerate raw LFL since it grew at 100% of LFL. However, this strain is inefficient in removing phenols and hydrocarbons. Consequently, toxicity abatement was very low (%BI > 70%).     

Detoxification of chromium slag by chromate resistant bacteria

This paper presented direct detoxification of chromium slag by using microorganisms. Our work showed that a bacterial consortium isolated from chromium slag can efficiently accelerate Cr(VI) leaching rate and remove it. The chromate resistant bacterial consortium consists of three strains. The detoxification efficiencies of the three respective strains follow the sequence: strain I > strain III > strain II. The detoxification capability of the bacterial consortium is far stronger than that of the respective strain, showing an excellent synergistic effect. The specific growth rates in pure and chromium-containing medium are 0.1475 and 0.1573 h(-1), respectively. The presence of Cr(VI) has little effect on growth rate of the bacterial consortium. Cr(VI) removal takes place in exponential growth period of the bacterial consortium; the detoxification time should be controlled in this phase for every run. The kinetics of detoxification process was studied and can be described as eta = 0.0615e(0.1573t), which can be used to predict Cr(VI) removal efficiency.     

Detoxification of a highly toxic lead-loaded industrial solid waste by stabilization using apatites

Apatites are known for their properties to immobilize lead contained in aqueous solutions or contaminated soils. In this study, apatites were examined as stabilization additives for lead-loaded industrial solid toxic wastes. The specific waste was the residue, obtained after thermal treatment of sludges (incineration), which was derived from tetraethyl lead fuel storage tanks. It was found to contain around 30 wt.% lead and 33 wt.% iron. Standard leaching tests (according to DIN 38414 S-4) were applied for the determination of leachability of metals from the ash and, thus, of chemical toxicity; the proposed leaching tests examined both initial and stabilized products in order to evaluate the effectiveness of the applied additives. The results obtained demonstrate the fact that lead concentrations in leachates, after the application of the proposed leaching tests using apatites as additives and with a ratio of 50% solid waste-50 wt.% apatite, could be reduced to the range of 1mg/l.     

HPLC测定油漆中的16种多环芳烃

建立HPLC测定油漆中的16种多环芳烃含量的方法,以FL2200-Ⅱ为高效液相色谱仪,Ultimate PAH-C18为色谱柱,乙腈和水为流动相,进行梯度洗脱,紫外检测器检测,检测波长为220 nm。结果表明16种组分在0.4～8 mg/L的浓度范围内均有良好的线性关系(r>0.999),其中检出限达0.04 mg/L,回收率均>80%。该方法快速,准确,重现性好,可用于测定油漆中的16种多环芳烃的含量。     

Detoxification of olive mill wastewater by electrocoagulation and sedimentation processes

Olive mill wastewater (OMW) is characterised by its high suspended solids content (SS), high turbidity (NTU), chemical oxygen demand (COD) concentration up to 100 gl(-1) and toxic phenolic compounds concentration up to 10 gl(-1). This study examined the effect of a physico-electrochemical method to detoxify olive mill wastewater prior an anaerobic biotreatment process. The proposed pre-treatment process consisted in a preliminary electrocoagulation step in which most phenolic compounds were polymerised, followed by a sedimentation step. The BOD(5)/COD ratio of the electrocoagulated OMW increased from 0.33, initial value, to 0.58. Furthermore, the sedimentation step yielded the removal of 76.2%, 75% and 71% of phenolic compounds, turbidity and suspended solid, respectively, after 3 days of plain settling. The combination of electrocoagulation and sedimentation allowed a COD reduction and decoloration of about 43% and 90%, respectively. This pre-treatment decreases the inhibition of Vibrio fisheri luminescence by 66.4%. Continuous anaerobic biomethanization experiments conducted in parallel with raw OMW and electrocoagulated OMW before and after sedimentation at a loading rate of 6g COD l(-1)day(-1), proved that the final pre-treated OMW was bioconverted into methane at high yield while raw OMW was very toxic to anaerobic microorganisms.     

Detoxification of methyl-parathion pesticide in aqueous solutions by electrochemical oxidation

Commercial methyl-parathion (MeP) was detoxified using an electrochemical method that employed a Ti/Pt anode and stainless steel 304 as cathode. Sodium chloride was added as electrolyte and the mixture was passed through an electrolytic cell for 2 h. Due to the strong oxidizing potential of the produced chemicals, the organic pollutants were wet oxidized to carbon dioxide and water. A number of experiments were run at laboratory scale. Reductions of COD and BOD(5) were both over 80% and the mean energy consumption was 18-8 kWh per kg(-1) COD reduced (COD(r)). The degradation of MeP was more effective when the pH of the brine solution was in the acid range than when it was in the alkaline range. From the results it can be concluded that electrolysis could be used as an oxidation pre-treatment stage for detoxification of toxic wastes with MeP.     

原子吸收光谱法间接测定樟树叶片中叶绿素总量

探讨了樟树叶片中叶绿素提取的条件,优化了原子吸收光谱仪的测定参数,建立了用无水乙醇作提取剂在研磨条件下提取叶绿素、用石油醚萃取以分离出有机镁、用0.8mol/L盐酸反萃取,使镁进入水溶液。采用火焰原子吸收分光光度法测定萃取液中的镁含量,从而间接测定樟树叶片中叶绿素的含量的分析方法。结果表明,方法的回收率为103~116%,相对标准偏差为4.8%。     

Artificial extracellular matrix for embryonic stem cell cultures: a new frontier of nanobiomaterials

Abstract

Nanobiomaterials can play a central role in regenerative medicine and tissue engineering by facilitating cellular behavior and function, such as those where extracellular matrices (ECMs) direct embryonic stem (ES) cell morphogenesis, proliferation, differentiation and apoptosis. However, controlling ES cell proliferation and differentiation using matrices from natural sources is still challenging due to complex and heterogeneous culture conditions. Moreover, the systemic investigation of the regulation of self-renewal and differentiation to lineage specific cells depends on the use of defined and stress-free culture conditions. Both goals can be achieved by the development of biomaterial design targeting ECM or growth factors for ES cell culture. This targeted application will benefit from expansion of ES cells for transplantation, as well as the production of a specific differentiated cell type either by controlling the differentiation in a very specific pathway or by elimination of undesirable cell types.     

Scanning electroporation of selected areas of adherent cell cultures

We present a computer-controlled scanning electroporation method. Adherent cells are electroporated using an electrolyte-filled capillary in contact with an electrode. The capillary can be scanned over a cell culture and locally deliver both an electric field and an electroporation agent to the target area without affecting surrounding cells. The instantaneous size of the targeted area is determined by the dimensions of the capillary. The size and shape of the total electroporated area are defined by these dimensions in combination with the scanning pattern. For example, striped and serpentine patterns of electroporated cells in confluent cultures can be formed. As it is easy to switch between different electroporation agents, the method is suitable for design of cell cultures with complex composition. Finite element method simulations were used to study the spatial distributions of the electric field and the concentration of an electroporation agent, as well as the fluid dynamics related to scanning and flow of electroporation agent from the capillary. The method was validated for transfection by introduction of a 9-base-pair-long randomized oligonucleotide into PC12 cells and a pmaxGFP plasmid coding for green fluorescent protein into CHO and WSS cells.     

有机硅改性丙烯酸树脂夜光涂料

用有机硅改性丙烯酸树脂作为主要成膜物质,将稀土硫化锌夜光颜料和铝酸锶铕夜光颜料分散于有机硅改性丙烯酸树脂中制成夜光涂料。结果表明,所得有机硅改性丙烯酸树脂稀土硫化锌夜光涂料和有机硅改性丙烯酸树脂铝酸锶铕夜光涂料的涂抹性能好,耐水性、耐碱性、耐候性和耐沾污性强,夜光性能好,余辉亮度强且余辉时间长,为优质的夜光涂料。     

Detoxification of simulated textile wastewater using a membraneless electrochemical reactor with immobilized peroxidase

Simulated textile wastewater was degraded using a membraneless electrochemical reactor with immobilized peroxidase on the porous Celite. The optimal current density was 10 A m(-2), at which the highest amount of hydrogen (H(2)O(2)) could be generated. The decolorization efficiencies of the simulated wastewater using the electrochemical and electroenzymatic methods were 35% and 92%, respectively. Biodegradability, the ratio of 5-day biochemical oxygen demand to chemical oxygen demand (BOD(5)/COD), was enhanced about 1.88 times when using the electroenzymatic treatment rather than raw wastewater, which could not be achieved by the electrochemical treatment. The toxic unit (TU), calculated using the lethal concentration (LC(50)) of Daphnia magna (D. Magna), of effluent treated by electroenzymatic method was below 1, whereas those of simulated textile wastewater and effluent treated by electrochemical method were 11.4 and 3.9, respectively.     

Identification of pigments in paint cross sections by reflection visible light imaging microspectroscopy

A setup for reflection visible light imaging microspectroscopy (VIS-imaging) as well as its evaluation and application is described and tested. The spatial resolution of the system is approximately 1 microm at a spectral resolution of 4 nm. The optical contrast between different colored particles in the surface of a sample is optimized with a new image processing method for mapping of the distribution of the identified pigment particles. The potential of VIS-imaging in the study of paint cross sections obtained from paintings is explored. Spectra obtained from pigment particles in these cross sections result in classification or identification of several pigments. The investigated paint samples are challenging test cases, as they contain several colored materials with a very fine distribution. VIS-imaging can identify and map the most common traditional blue pigments, i.e., smalt, azurite, ultramarine, and indigo in 17th century oil paintings. Smalt can be identified even after complete discoloration. VIS-imaging analysis assisted in the identification and mapping of modern synthetic red and yellow pigments in a 20th century painting.