Evaluation of the surface tension measurement of axisymmetric drop shape analysis (ADSA) using a shape parameter

A quantitative criterion called “shape parameter” to evaluate the quality of surface tension measurement of Axisymmetric Drop Shape Analysis (ADSA) is presented. ADSA is a powerful technique for the measurement of interfacial tensions and contact angles of pendant drops, sessile drops, and bubbles. Despite the general success of ADSA, deficient results may be obtained for drops close to spherical shape. Therefore, the “shape parameter” was used to determine the range of drop shapes in which ADSA succeeds or fails. The “shape parameter” is a dimensionless parameter that expresses quantitatively the difference in shape between a given experimental profile and an inscribed circle. The surface tension measurements of ADSA were evaluated for both pendant drop and constrained sessile drop configurations using the shape parameter. Different shapes of the pendant drop were studied using different sizes and materials of holders. For each drop configuration, a “critical shape parameter” was defined based on the minimum value of the shape parameter that guarantees an error of less than ±0.1 mJ/m². Furthermore, the effects of the type of liquid and constellation on the “critical shape parameter” were studied.     

Discriminant Analysis of Volatile Organic Compounds data related to a new location method of entrapped people in collapsed buildings of an earthquake

Discriminant Analysis is used as a part of a research, which aims at using expired air analysis for the early location of entrapped people under the ruins of collapsed buildings in an earthquake. This work focuses on the possibility of distinguishing Volatile Organic Compounds (VOCs) in the entrapment area which originate from different sources. Five categories of samples were analyzed by Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS). Expired air samples from healthy humans (Category 1) and fasting people (Category 2) were analyzed for studying the VOCs attributed to entrapped people. Headspace air of urban waste disposal bins (Category 3), headspace air of bags with decaying human bodies (Category 4) and urban air samples (Category 5) were analyzed for studying the VOCs attributed to background sources. Discriminant Rotation, a specific type of Discriminant Analysis was applied on the VOCs concentration matrix of the five categories. Combinations of VOCs that best discriminated each category were determined. Cluster Analysis was used to validate the results of Discriminant Analysis. The advantages and limitations of the method are presented and discussed.     

Efficient synthesis of magnetic nanoparticle-Musa acuminata peel composite for the adsorption of anionic dye

The impregnation of magnetite (Mt) nanoparticle (NPs) onto Musa acuminata peel (MApe), to form a novel magnetic combo (MApe-Mt) for the adsorption of anionic bromophenol blue (BPB) was studied. The SEM, EDX, BET, XRD, FTIR and TGA were used to characterize the adsorbents. The FTIR showed that the OH and CO groups were the major sites for BPB uptake onto the adsorbent materials. The average Mt crystalline size on MApe-Mt was 21.13 nm. SEM analysis revealed that Mt NPs were agglomerated on the surface of the MApe biosorbent, with an average Mt diameter of 25.97 nm. After Mt impregnation, a decrease in BET surface area (14.89 to 3.80 m²/g) and an increase in pore diameter (2.25–3.11 nm), pore volume (0.0052–0.01418 cm³/g) and pH point of zero charge (6.4–7.2) was obtained. The presence of Pb(II) ions in solution significantly decreased the uptake of BPB onto both MApe (66.1–43.8%) and MApe-Mt (80.3–59.1%), compared to other competing ions (Zn(II), Cd(II), Ni(II)) in the solution. Isotherm modeling showed that the Freundlich model best fitted the adsorption data (R² > 0.994 and SSE < 0.0013). In addition, maximum monolayer uptake was enhanced from 6.04 to 8.12 mg/g after Mt impregnation. Kinetics were well described by the pseudo-first order and liquid film diffusion models. Thermodynamics revealed a physical, endothermic adsorption of BPB onto the adsorbents, with ΔH^o values of 15.87–16.49 kJ/mol, corroborated by high desorption (over 90%) of BPB from the loaded materials. The viability of the prepared adsorbents was also revealed in its reusability for BPB uptake.     

Preparation,purification, and analysis of alkylated cyclodextrins

Methods of alkylation of α-, β- and γ-cyclodextrins have been optimized with regard to the parameters of reaction, degree of alkylation and yields. The analysis of the reaction mixtures and of the isolated single species has been performed by high temperature GC and HPLC. The phase systems of the preferably applied HPLC have been carefully adjusted by variation of both the stationary and mobile phases to the very different hydrophobicities of the various alkylated CD species which have been synthesized. Several partially or fully alkylated CD species were isolated from preparative scale HPLC separations in high purity.     

Molecular Chains in the Crystals of a Calcium(II) Complex with Pyridine-3,5-Dicarboxylate (Dinicotinate) and Water Ligands

The crystal of pentaqua (catena-pyridine-3,5-dicarboxylato-O,O) calcium(II) contain zigzag molecular chains composed of Ca ions linked by two bridging oxygen atoms, each donated by one carboxylate group [Ca-O1 2.353(2) Å, Ca-O3^III 2.334(1) Å]. The Ca ions, the ligand molecules and one water oxygen atom coordinated by each metal ion [Ca-O5 2.410(2) Å] are coplanar. The coordination of the Ca ion is completed by four other water oxygen atoms situated above and below the plane of the chain [Ca-O6 2.475(1) Å, Ca-O7 2.371(2) Å]. The coordination number of the calcium(II) ion is seven. The water molecules act as donors in a system of hydrogen bonds.     

Determination of Paint Solvents by Vapour Phase Fourier Transform Infrared Spectrometry.

A fast procedure has been developed for the direct determination of paint solvents. The method is based on the injection of small volumes of untreated solvent mixtures into a heated Pyrex glass reactor in which the sample is volatilized and introduced by means of a flow of nitrogen into an IR multiple pass gas cell and the spectrum in the mid-IR region is registered as a function of time. Data found for samples are interpolated in calibration graphs obtained by injecting different volumes of pure compounds which constitute the solvent mixture. A methylisobutylketone (MIBK) toluene mixture was used as test system to develop the proposed procedure. The method provides a limit of detection of the order of 1–4 μg, a relative standard deviation of the order of 0.4 to 2% for five independent measurements, and recovery percentage values from 99.8 till 103.6 %. A commercial sample of polyurethane paint solvent has been analysed by the developed procedure.     

On the hybrid multi-watermarking

Multi-watermarking is the technique to embed multiple messages into the same media content repeatedly. It can be used to identify media content's ownership or trace the illegal redistributors in media distribution. However, some performances of multiple watermark embedding, e.g., the distortion and security, are not considered carefully in the previous work. In this paper, the application scenario and framework of hybrid multi-watermarking are figured out, which show the secure media distribution model suitable for hierarchical media distribution. Additionally, the multi-watermarking based on hybrid multiplicative rule is firstly proposed and then analyzed theoretically with respect to two cases, i.e., the multi-embedding of same watermark sequence and the multi-embedding of different watermark sequences. The analysis emphasizes on four aspects, i.e., robustness, capacity, distortion and security, each of which considers two cases, i.e., the authorized embedding and unauthorized embedding. What is more, the locally optimum detector for multi-watermarking of hybrid multiplicative rule is reduced, and some potential attacks are investigated. Additionally, for each case, some suggestions are proposed to improve the system's performance. Finally, some comparative experiments are done, and results are given to show the validity of the theoretical analysis.     

Research on HTML5 application cache poison attack

HTML5 application cache (AppCache) allowed Web browser to access Web offline.But it also brought a new method of cache poisoning attack that was more persisting.As for websites which used the AppCache,a novel poisoning method RFTM (replace file twice method),in which the attacker replaced the manifest file twice to poison the client’s AppCache,was proposed.Compared with the original attack,the legal server would not receive abnormal HTTP requests from the client in the attack.Therefore,changing the server configuration could not prevent the client from the RFTM AppCache poisoning.To avoid the attack mentioned above,a lightweight signature defense scheme Sec-Cache in application layer was designed.Furthermore,experiments show that it has good performance and compatibility.     

Effect of purified fractions from cell culture supernate of high‐density pre‐B acute lymphoblastic leukemia cells (ALL3) on the growth of ALL3 cells at low density

The mechanisms underlying the aberrant growth and interactions between cells are not understood very well. The pre‐B acute lymphoblastic leukemia cells directly obtained from an adult patient grow very poorly or do not grow at all at low density (LD), but grow better at high starting cell density (HD). We found that the LD ALL3 cells can be stimulated to grow in the presence of diffusible, soluble factors secreted by ALL3 cells themselves growing at high starting cell density. We then developed a biochemical purification procedure that allowed us to purify the factor(s) with stimulatory activity and analyzed them by nanoliquid chromatography‐tandem mass spectrometry (nanoLC‐MS/MS). Using nanoLC‐MS/MS we have identified several proteins which were further processed using various bioinformatics tools. This resulted in eight protein candidates which might be responsible for the growth activity on non‐growing LD ALL3 cells and their involvement in the stimulatory activity are discussed.