Measurement method for the objective and early detection of the osteosarcoma tumors

This paper deals with the characterization, by means of measurement techniques typically used for ceramics and polymeric materials, of human bone samples affected by two aggressive tumors: osteolitic osteosarcoma and sclerotic osteosarcoma. These two common forms of osteosarcoma often affects children and young teenagers. To distinguish between healthy and diseased bone tissue, the Hydroxyapatite/Collagen ratio and the Hydroxyapatite composition (Calcium/Phosphorus molar ratio) are evaluated. The results allow two considerations to be drawn on the analysis of human bone samples. The first consideration is that the bone affected by osteosarcoma has a greater amount of Collagen with respect to the healthy one. This can be used to evaluate the pathologic status of bone tissues. The second consideration is that the Calcium/Phosphorus molar ratio is, with respect to the one of healthy bone, higher in bone tissue affected by osteolitic osteosarcoma, while is lower in the one affected by sclerotic osteosarcoma. On the basis of these considerations, a promising measurement method is proposed to support the early and objective detection of the osteosarcoma tumor and to distinguish between osteolitic and sclerotic forms. The proposed measurement method can be executed in a few minutes and by using few milligrams of bone tissue that can be drawn with a needle under local anesthesia.     

Effect of NOx on AgI formation in Ag-mordenite

Ag loaded mordenite can be used as a trap for radio-iodine arising from nuclear reprocessing operations. Typically, iodine is trapped in the Ag loaded mordenite by the formation of AgI in the pores of the mordenite, through a solid-vapour reaction. In the presence of NO_x and water vapour, AgI is most likely formed by liquid-vapour reaction between AgNO₃ and I₂. This reaction results in the formation of large aggregates of AgI crystals on the surface of the mordenite, also leading to a yellow colouration of the mordenite, which is not observed when NO_x and water vapour is absent.     

Effect of the oxygen deficiency on the physical properties of Ca2MnO4−δ compounds

In this work, structural and magnetic studies have been investigated to explore the influence of the oxygen-deficiency (δ) on the physical properties of Ca₂MnO_4−δ (δ = 0 to 0.5) compounds. The samples cationic stoichiometry has been studied using energy dispersive X-ray analysis (EDAX). EDAX spectra, taken from the surface of the synthesized powders, have showed a nominal composition near the desired one. The structural study, by X-ray diffraction analysis, has confirmed the single-phase composition of all samples. The Rietveld refinement technique of the X-ray patterns, has revealed that samples crystallize in the tetragonal system with I41/acd space group for δ = 0 and in the orthorhombic one with Bbcm space group for δ > 0.The applied magnetic field (μ₀H) and the temperature (T) dependences of the magnetization (M) have been studied using a vibrating sample magnetometer (VSM). From magnetization measurements versus temperature under the field-cooled (FC) and zero-field-cooled (ZFC) modes, we have deduced the presence of a spin-glass behavior characterized by a distinctive separation of the FC and ZFC curves. This behavior was found to become more important, as increasing the oxygen-deficiency δ, which leads to the appearance of magnetic frustration phenomenon.     

Lanthanum samarium oxalate — its growth and structural characterization

Lanthanum samarium oxalate (LSO) single crystals are grown in silica gels by the diffusion of a mixture of aqueous solutions of lanthanum nitrate and samarium nitrate into the test tube having the set gel impregnated with oxalic acid. Tabular crystals of LSO having well defined hexagonal basal planes are observed at different depths inside the gel. LSO crystals grown by this method are colourless and transparent. Laue transmission X-ray diffraction pattern of LSO reveals well defined spots with two-fold symmetry along the horizontal axis. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) support that LSO loses water around 120°C, and CO and CO₂ around 350–450°C. The infrared (IR) absorption spectrum of LSO establishes the presence of oxalate (C₂ O₄)²⁻ ions. Energy dispersive X-ray analysis (EDAX) confirms the presence of La and Sm in the sample. X-ray photoelectron spectroscopic (XPS) studies of LSO confirm the presence of La and Sm in their respective oxide states. An empirical structure for LSO has been proposed on the basis of these findings.     

Some structural aspects of neodymium praseodymium oxalate single crystals grown in hydro silica gels

The mixed crystals of neodymium praseodymium oxalate are grown by the diffusion of a mixture of aqueous solutions of neodymium nitrate and praseodymium nitrate (as an upper reactant) into the set gel embedded with oxalic acid. By varying the concentration (by volume) of rare earth nitrates in the upper reactant, the incorporation of Nd and Pr in the mixed crystals has been studied. Tabular crystals with the well defined hexagonal basal planes are observed in the mixed crystals of varying concentrations. X-ray diffraction patterns of these powdered samples reveal that these mixed crystals are ‘isostructural’, while IR and FTIR spectra establish the presence of oxalate groups. TGA and DSC analyses show the correctness of the chemical formula for the mixed crystals, by the release of water molecules (endothermic) and of CO and CO₂ (exothermic), with the rare earth oxides as the stable residue. X-ray fluorescence (XRF) and energy dispersive X-ray analyses (EDAX) establish the presence of heavy rare earth elements qualitatively and to a good extent quantitatively. X-ray photoelectron spectroscopic (XPS) studies confirm the presence of rare earth elements (Nd and Pr) as their respective oxides. The findings of these techniques of characterization are in excellent agreement with the proposed empirical structure for the mixed rare earth oxalates. The implications are discussed.     

Electrical and morphological analysis of chitosan:AgTf solid electrolyte

Solution cast technique is employed to prepare solid polymer electrolyte films based on chitosan (host polymer) and silver triflate (AgCF₃SO₃, doping salt) using (1%) acetic acid as a common solvent. The effect of salt concentration on both EP and bulk materials dielectric properties has been analyzed. Physically the original relationship between the bulk dielectric constant and DC conductivity has been interpreted. It is demonstrated that the dielectric constant and dielectric loss values decrease at higher temperatures due to the reduction of silver ions. Scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) indicate the presence of metallic silver particles. The ac conductivity spectra shows three distinct regions and obeys the Jonscher's power law at high frequency regions. The temperature dependence of frequency exponent (s) shows the crossover from CBH model to SP model.     

CdS microflowers and interpenetrated nanorods grown on Si substrate: Structural,optical properties and growth mechanism

CdS semiconductor with different morphologies have been achieved by simple thermal evaporation of CdS powder at 1050 °C in a flowing Ar atmosphere. The products were characterized by X-ray diffraction, Scanning electron microscopy, Transmission electron microscopy and Photoluminescence. microflowers and interpenetrative nanorods of CdS were formed on catalyst free Si wafers at a temperature of 700 °C and 600 °C respectively. The flower like structures are composed of many interleaving nanorods which have the uniform diameter of about 700 nm and a well crystalline structure with [0001] as growth direction. The interpenetrative nanorods are found to be bounded with six side facets. X-ray diffraction studies revealed the hexagonal structure in both the products. The formation mechanism of microflowers and interpenetrated nanorods was discussed on the basis of nucleation growth kinetics. Room temperature photoluminescence spectra showed a strong green emission band (at ∼510 nm) from the CdS flower like structures, but on the other hand a red emission shoulder along with strong green emission band was observed for interpenetrative nanorods. These CdS micro/nanostructures with abundant morphologies may find applications in various micro/nanodevices, and the kinetics-driven morphology might be exploited to synthesize similar structures of other functional II–VI semiconductors.     

Isolation and characterization of biologically metal-doped protein as semiconducting biopolymer

Metal-doped (Cu₂O, CdO and PbO) muscle protein from fish (Clarious batracus Lin.) was isolated, purified and characterized for its potential as semiconducting biopolymer. The initial characterization of the isolated protein was carried out by circular dichrosim (CD), FTIR and AAS. Protein thin film was prepared using polyvinyl alcohol (PVA) and characterized for its surface morphology by SEM/EDAX and crystallinity by XRD spectrum. The physical properties such as Raman shift, optical coefficient and electron transfer reaction such as electrical conductivity, temperature dependent conductivity and cyclic voltammeter (CV) were studied. The present study concludes that the Cd and Cu-doped fish protein behaves like semiconductor and has the potential application in molecular electronics like protein semiconductors, protein based (proton exchange membrane) fuel cell, drug delivery and nanotechnology.     

Examination of tribological properties of plasma surface layer using special test equipment

The hardness, adhesion, and tribological behaviour of magnetron-deposited coatings (TiN and (Ti,Al)N) have been determined and related to microstructure composition. To enhance the adhesion of the coating, plasma nitriding of substrates was employed. Wear behaviour, coefficient of friction and contact temperature were measured using computerised data acquisition and processing. The bonding force between the coated samples and counter material was monitored and controlled by newly designed and constructed equipment, to keep a constant level of load during sliding. With the new hardware and software, it was possible to monitor on-line the development of the wear process. The hardware consisted of PC computer, piezoelectric transducer, sensors with high sensitivity, microprocessor-controlled measuring system, AD/DA transformer, and multichannel plotter. The wear zone morphology and characteristics of the surface layer structure and other important properties were investigated using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Energy dispersive X-ray analysis (EDAX) of the wear scars on pins provided essential information on the wear characteristics. Based on the results, the correlations between the mechanical properties, the surface structure, and tribological characteristics are explained.     

蔗秆表皮层的SEM-EDAX研究

用SEM-EDAX法研究蔗秆表皮层的超微结构及元素组成。结果表明，在实验条件下，蔗秆表皮层的外表面由C、O、Mg、Al、Si、Cl6种元素组成，Si的含量为30．464％；颗粒状物的Si含量为53．833％。蔗秆表皮层径切面中含C、O、Mg、Al、Si、K、Ca7种元素，自外向里各种元素的含量呈规律性变化。表皮层是Si等矿质元素高度密集、超微结构非常复杂的多层结构；表皮层中的Si绝大部分在碱法制浆的低温蒸煮阶段就被溶解转移到黑液中，残留物几乎为纯C组成。蔗秆表皮层的超微结构、Si等元素的存在状态及脱除机理有待进一步研究。