Gas Permeation Characteristics of TiO2-ZrO2-Aromatic Organic Chelating Ligand (aOCL) Composite Membranes

Methyl gallate (MG) and ethyl ferulate (EF) with a benzene ring were separately used as aromatic organic chelating ligands (aOCLs) to prepare two versions of TiO2-ZrO2-aOCL composite sols via hydrolysis and polycondensation reactions with titanium(IV) isopropoxide (Ti(OC3H7)4) and zirconium(IV) butoxide (Zr(OC4H9)4). Thermogravimetric and FT-IR analysis of dry gels revealed that aromatic rings were present in the residual organic matter when the gel was fired under nitrogen at 300 °C. In X-ray diffraction (XRD) measurements, the TiO2-ZrO2 composite material prepared using these two aOCLs showed an amorphous structure with no crystalline peaks for TiO2 and ZrO2. In N2 adsorption/desorption measurements at 77 K, the TiO2-ZrO2 samples using the aOCLs as a template appeared porous with a larger specific surface area than TiO2-ZrO2 without aOCL. TiO2-ZrO2-aOCL composite membranes were prepared by coating and firing TiO2-ZrO2-aOCL sol onto a SiO2 intermediate layer using an α-alumina porous tube as a substrate. Compared with the TiO2-ZrO2 membrane, the TiO2-ZrO2-aOCL membranes had higher gas permselectivity. The TiO2-ZrO2-EF membrane showed a He permeance of 2.69 × 10−6 mol m−2 s−1 Pa−1 with permeance ratios of He/N2 = 10.6 and He/CF4 = 163, while the TiO2-ZrO2-MG membrane revealed a bit less He permeance at 8.56 × 10−7 mol m−2 s−1 Pa−1 with greater permeance ratios of He/N2 = 61.7 and He/CF4 = 209 at 200 °C. A microporous TiO2-ZrO2 amorphous structure was obtained by introducing aOCL. The differences in the side chains of each aOCL could possibly account for the differences in the microporous structures of the resultant TiO2-ZrO2-aOCL membranes.

Assessing organic material on single-use vessel sealing devices: a comparative study of reprocessed and new LigaSure™ devices

Background Reprocessed devices must be thoroughly cleaned prior to sterilization to ensure efficacy of sterilization agents. Many single-use devices are not designed to be thoroughly cleaned. Interlocking design features inherent to LigaSure™ vessel sealing devices may prevent thorough cleaning and promote accumulation of human tissue that cannot be removed. Thus, the aim of this study was to compare industry reprocessed and new LigaSure™ vessel sealing devices for organic material. Methods A total of 168, 84 new and 84 reprocessed, vessel sealing devices were disassembled and inspected for the presence of residual organic matter using visual, microscopic, and chemical analysis. Devices were randomized and test conductors blinded to group membership. Devices were aseptically disassembled and sent through visual inspection. Next, devices were either examined using light microscopy, scanning electron microscopy (SEM) or exposed to a solution that luminesces in the presence of hemoglobin. Additionally, 165 reprocessed devices were sent to a 3rd party lab for sterility testing via direct immersion culture for 14 days. Results Significant amounts of remnant organic material (C, N, O, S, Na, P) were observed with 81/84 reprocessed and 0/84 new devices failing inspection protocols. When tested for the presence of hemoglobin, only 1/12 reprocessed devices passed inspection. SEM of reprocessed devices revealed residues with liquid patterns and diffuse soiling with foreign material. Sterility testing of reprocessed devices revealed a sterility level < 6–3. Conclusions The abundance of material resembling human tissue observed on reprocessed VSDs suggests inadequate cleaning prior to sterilization. Atomic and morphological analyses of the remnant materials suggest that bacterial biofilms could also be present. Additionally, surface degradation and release of reinforcing glass fibers from the device were observed. Devices designed for single use can harbor significant amounts of remnant material that likely interfere with the sterilization process.

Continuous hydrogen and methane production from the treatment of herbal medicines wastewater in the two-phase ‘UASBH-ICM’ system

A two-phase anaerobic system comprised of upflow anaerobic sludge bed (UASB) reactor for hydrogen production and internal circulation reactor (IC) for methane production was proposed and investigated at laboratory scale and mesophilic temperature (35 °C). Hydrogen was efficiently produced from the UASB with the highest production rate of 3.00 ± 0.04 L · L−1reactor · d−1 at optimum hydraulic retention time (HRT) of 6 h and in the IC, methane was also produced from residual organic matter and soluble metabolite products (SMP) with a production rate of 2.54 ± 0.04 L · L−1reactor · d−1 at optimum HRT of 15 h. Finally, system HRT of 21 h was determined to be the optimum HRT at which energy conversion efficiency increased from 9.6 ± 0.1% (hydrogen only production) to 72.4 ± 2.5% (hydrogen and methane coproduction) and system chemical oxygen demand (COD) removal reached up to the high level of 90.1 ± 2.1%.

Researches Regarding the Improvment of Different Dental Contemporary Composite Materials Structure

The purpose of this study was to test the structural improving that may be acquired by adding hydroxyapatite microparticles bearing or not silver nanoparticles to three different commercial products commonly used in dental practice. The practical part of this study consisted in the preparation of a common protocol of nine samples resulting from the creation of cavities and their filling similarly to the solving of different clinical situations of carious processes, extracted teeth belonging to both the anterior and the posterior area, with different architectures of the loss of dental substance. Before use, both HA and HA/AgNP have been subjected to calcination in an oven at 6000C for three hours in order to eliminate the residual organic matter. The structural changes have been studied on three types of composites known in the medical practice under the tradenames of Ceram X Duo, Swiss Tec and Herculite XRV Ultra. The structural changes materialized at the level of dentinal component are clearly visible in the SEM images recorded for each starting commercial material. Thus, the addition of HA with high polydispersity (within the range of tens of nanometers and several microns) was effective on lowering the surface rugosity and apparent macro-porosity, while enhancing the phase mixing and component cohesion, but only in the case of Ceram X Duo and Swiss Tec materials. For Herculite XRV Ultra these effects seems to be limited or even reversed, phenomenon that could be explained by the fact that this material already contains nano-fillers, and their concentration tends to saturation.

Fabrication of attapulgite/carbon composites from spent bleaching earth for the efficient adsorption of methylene blue

In this work, one-dimensional attapulgite/carbon composites were prepared by a one-step carbonization process using the residual organic matter of spent bleaching earth as a low-cost available carbon precursor.