Formulation,optimization, and evaluation of raft-forming formulations containing Nizatidine

Objective: The main objective of this research is to formulate, optimize, and evaluate raft-forming chewable tablets of Nizatidine. Various raft-forming agents were used in preliminary screening. Sodium alginate showed maximum raft strength, so tablets were prepared using sodium alginate as the raft forming agent, along with calcium carbonate (CaCO₃) as antacid and raft strengthening agent, and sodium bicarbonate (NaHCO₃) as a gas generating agent.

Research design and methods: Raft forming chewable tablets containing Nizatidine were prepared by direct compression and wet granulation methods, and evaluated for drug content, acid neutralization capacity, raft strength, and in-vitro drug release in 0.1?N HCl. Box–Behnken design was used for optimization.

Results: Two optimized formulations were predicted from the design space. The first optimized recommended concentrations of the independent variables were predicted to be X₁?=?275.92?mg, X₂?=?28.60?mg, and X₃?=?202.14?mg for direct compression technique and the second optimized recommended concentrations were predicted to be X₁?=?253.62?mg, X₂?=?24.60?mg, and X₃?=?201.77?mg for wet granulation technique. Optimized formulations were stable at accelerated environmental testing for six months at 35?°C and 45?°C with 75% relative humidity. X-Ray showed that the raft floated immediately after ingestion and remained intact for ～3?h.

Conclusion: Raft was successfully formed and optimized. Upon chewing tablets, a raft is formed on stomach content. That results in rapid relief of acid burning symptoms and delivering the drug into systemic circulation with enhanced bioavailability.     

Investigation of foreign substances in food using scanning electron microscopy-x-ray microanalysis

Scanning electron microscopy (SEM) and x-ray microanalysis (EDS) were used to conduct forensic investigations on metal and glass foreign objects. SEM-EDS is an excellent method for identifying metal foreign objects in food, such as wire, dental fillings, bone, and metal packaging, based on their element composition. From a determination of the extent of corrosion of a metal foreign object using SEM-EDS, it is sometimes possible to determine whether the material has been processed with the food product. Case histories of processed aluminum, unprocessed nickel-coated steel, and corrosion resistant stainless steel foreign objects are discussed. A potential product-tampering problem involving a hole defect in a paperboard package was resolved using SEM-EDS. Blue fibers found in the hole were found to contain brass particles from a ball point pen rather than a syringe needle. SEM-EDS has been used to determine the elemental composition of glass foreign objects and is able to distinguish between many types of glass including container, electrical, and bakeware. A case history is presented to show that although container glasses cannot, in general, be distiguished from one another using SEM-ED S, they can be distinguished by trace element semiquantitative spectrograghic analysis. SEM-EDS can be used to distinguish glass-like foreign objects from glass. Case histories of struvite crystals found in salmon and cream of tartar crystals found in grape juice are discussed. Fourier transform infrared (FTIR) identified the cream of tartar crystal as calcium tartrate, and this complemented the calcium, carbon, and oxygen components of the compound found using SEM-EDS.     

碳纳米管场发射X光源测控系统设计

现有的X射线源多采用热阴极,工作温度高、功耗大、不易实现多个阴极的集成和可编程控制。本实验室研制的新一代基于碳纳米管冷阴极场发射X光源系统,可以突破传统热阴极X射线源的上述缺陷,同时为CT系统实现高时间分辨,减少辐射剂量提供新的路径。针对新制备的CNT阴极场发射性能测试的需求,利用Lab VIEW软件平台设计了碳纳米管场发射X光源测控系统,该系统进行多次试验检验运行稳定可靠、自动化程度高、操作简便,能够实现对X光源的可编程控制,为稳定CNT阴极发射电流、提高阳极电压、材料老化提供可靠的测控平台。     

Hydrogenation reaction of Co3Ti alloy under high pressure and high temperature

To synthesize a novel titanium-containing hydride, a Co₃Ti alloy with a Cu₃Au-type structure was hydrogenated at 9 GPa and 900 °C. Structural changes under high pressure were monitored via in situ synchrotron radiation x-ray diffraction at BL14B1, SPring-8. The in-situ measurement reveals that novel hydride Co₃TiH_~4 is formed at 9 GPa and 900 °C. When the sample was depressurized at room temperature, the formed hydride decomposed to (the previously reported) Co₃TiH_~1 at a pressure of ~1 GPa. Co₃TiH_~1 was recovered at ambient conditions and decomposed gradually into the Co₃Ti alloy. Co₃TiH_~4 is thermodynamically stable only at pressures above 1 GPa.     

Microstructural and phase characterisation of pyrolytic graphite coating by CVD using propane and methane as precursor

Pyrolytic graphite (PyG) coatings on high-density graphite (HDG) substrates were deposited by chemical vapour deposition using propane and methane as precursor gas at aprocess temperature of 1800°C. Upon cooling to room temperature, cracking and delamination were observed in the PyG layer at certain edges of flat substrates deposited in propane cycle, attributed to large thermal expansion mismatch stresses. The PyG coatings deposited using different precursor hydrocarbon sources were characterised using polarised light microscopy, scanning electron microscope, X-Ray diffraction analysis, Laser Raman Spectroscopy and X-ray Photoelectron Spectroscopy. Microstructure analysis revealed coarse structure cones grown with larger cone angles. The large deposition rate, associated growth and thermal stress in the case of propane cycle have led to the cohesive delamination of the PyG coating. Nickel melting studies to simulate the uranium melting was carried out in PyG coated HDG crucibles whichshowed reactive dissolution of PyG at the Ni/crucible interface.     

Structural studies of copper sulfide films: effect of ambient atmosphere

Abstract

We examined the structural properties of copper sulfide films as a function of the sulfurization time of 70-nm-thick Cu films. Copper sulfide films with various phases such as mixed metallic Cu-chalcocite, chalcocite, roxbyite, and covellite phases were formed with increasing sulfurization time. To evaluate the structural stability of various films, all the films were exposed to the ambient atmosphere for the same amount of time. Although the phase structure and stoichiometry of the films were maintained at a greater depth, the near-surface region of the films was oxidized and covered with overlayers of oxide, hydroxide, and/or sulfate species due to the exposure and reaction with the ambient atmosphere. The oxygen uptake and its reactivity with the copper sulfide film surfaces were enhanced with increasing sulfur content of the films. In addition, the type of divalent state of copper formed on the film surfaces depended on the phase structure, composition, and stoichiometry of the films.     

Tetrathiapentalene-based organic conductors

Abstract

The synthesis, structure and properties of tetrathiapentalene-based (TTP) organic conductors are reviewed. Among various TTP-type donors, bis-fused tetrathiafulvalene, 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) and its derivatives afford many metallic radical cation salts stable down to low temperatures, regardless of the size and shape of the counter anions. Most BDT-TTP conductors have a β-type donor arrangement with almost uniform stacks. Introduction of appropriate substituents results in molecular packing that differs from the β-type. A vinylogous TTP, 2-(1,3-dithiol-2-ylidene)-5-(2-ethanediylidene-1,3-dithiole)-1,3,4,6-tetrathiapentalene (DTEDT) has yielded an organic superconductor (DTEDT)₃Au(CN)₂ as well as metallic radical cation salts, regardless of the counter anions. (Thio)pyran analogs of TTP, namely (T)PDT-TTP and its derivatives produce molecular conductors with novel molecular arrangements. A TTP analog with reduced π-electron system 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP) has afforded several organic superconductors. Highly conducting molecular metals with unusual oxidation states (+1, +5/3 and neutral) have been developed on the basis of 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) derivatives and analogous metal derivatives M(dt)₂ (M = Ni, Au).     

Sugar-free aerated chocolate: Production,investigation of bubble features using X-ray computed tomography and image processing

In contrast to other imaging techniques, X-ray imaging does not destruct the internal structure of the sample being imaged. Furthermore, this technique is able to capture numerous images of the sample at a low slice thickness, which is almost impossible in other imaging techniques. In this study, sugar was replaced with inulin:maltodextrin mixtures at ratios of 25:75 (i25), 50:50 (i50), and 75:25 (i75). Then, nitrogen (N₂) and carbon dioxide (CO₂) were injected into the three mixtures as well as the sugar-containing sample (control) at pressures of 3, 4.5, and 6 bar to produce aerated chocolate. The images of the samples were captured using X-ray computed tomography (XCT). After processing, they were segmented using the Chan–Vese model. Image segmentation showed that the Chan–Vese method, compared with adaptive thresholding, was more able to segment the images and remove the noise. The bubble total volume (10440 ± 9206 mm³) and average diameter (1.30 ± 0.10 mm) of the control were larger than those of the other samples. The results also demonstrated that the sugar-free aerated samples had lower hardness than the corresponding unaerated ones. However, it was reversed in the case of the control. This research sheds light on the industrialization of the production of aerated chocolate and the application of XCT and image processing in the analysis of the microstructure of aerated products.     

Mechanical and tribological properties of TiN and SiCN nanocomposite coatings deposited using methyltrichlorosilane

The paper examines nanocomposite coatings based on TiN and SiCN obtained by plasma-enhanced chemical vapor deposition (PECVD) using methyltrichlorosilane (MTCS) as one of the precursors. The nanocomposite coatings demonstrate four types of structures depending on deposition modes: nc-TiN, nc-TiN/a-SiCN, nc-TiNC/nc-TiSi₂/a-SiCN, and nc-TiNC/nc-TiCl₂/a-SiCN. The nanohardness and elastic modulus of the coatings reach 31 and 350 GPa, respectively. The coatings on substrates of hard alloys, high-speed steel, and silicon increase the nanohardness of the base from 10 to 100%. The correlation between the H/E ratio and wear resistance is not observed. The coatings deposited at low radiofrequency powers demonstrate good adhesion to silicon substrates. It is shown that the use of MTCS as the main precursor allows one to obtain hard and wear-resistant nanocomposite coatings. __________ Translated from Poroshkovaya Metallurgiya, Vol. 47, No. 1–2 (459), pp. 125–133, 2008.     

Fat microstructure of yogurt as assessed by x-ray microtomography

In this work, the x-ray microtomography (μCT) technique was used for the analysis of fat microstructure and quantification of fat in 7 types of yogurts. The dynamic mechanical properties of the yogurt samples also were studied using a controlled-strain rotational rheometer and correlated to the fat microstructure. Five types of commercially produced and 2 homemade yogurts, chosen to exhibit variability in terms of visible structure of fat, were used for this experiment. Appropriate quantitative 3-dimensional parameters describing the fat structure were calculated. With regard to the microstructural and rheological relationship, results from the correlation carried out show that a correlation exists among some microstructural and rheological parameters of the yogurt samples. The results from this study also show that μCT is a suitable technique for the microstructural analysis of fat as it not only quantifies the fat deposits present, but also determines the deposits’ spatial distribution.