Conventional Gel Research Articles

Nanocellulose-Strengthened Particle Gel for Conformance Control in Fractured Tight Formations. Part I: Preparation and Mechanical Stability

Conformance control in fractured tight formations remains a challenge because of large permeability contrasts between fractures and the matrix. Therefore, there is an emerging interest in particle gels that possess favorable mechanical properties and low production costs. To address this issue, we proposed a kind of nanocellulose-strengthened particle gel, named NC-st-PG, which was prepared by sparsely interpenetrating cellulose nanofibrils (NCF) and nanocrystals (NCC) respectively into a polyacrylamide (PAAm) matrix. The characteristics of NC-st-PG from the chemical structure to mechanical and thermal stability were investigated thoroughly. We noted that the PAAm network was noticeably strengthened and toughened by introducing stiff NC segments without compromising the elasticity of the gels. The optimum amount of NCF and NCC in the PAAm was found to be 0.1 wt %. We cycled the deformation and observed that NC-st-PG exhibited fatigue-resistance and remained highly elastic after 10 cycles of stress load and unload. In addition, the swelling and thermal decomposition of NC-st-PG were restrained by the presence of NCC and NCF. These characteristics render NC-st-PG superior stability under consecutive shearing in fractures and are indicative of the efficiency and durability of conformance treatment using NC-st-PG. The results of this study supplement earlier observations and provide an alternative to conventional gels to address conformance issues in tight formations.

Preparation and characterization of sumatriptan loaded solid lipid nanoparticles for transdermal delivery

Over the past decade, there has been great attention paid to the development of transdermal delivery systems for sumatriptan, the most commonly prescribed drug for the treatment of migraine headaches. Given the various gastrointestinal side effects of sumatriptan in oral administration and low bioavailability in nasal dosage forms, focus has been on transdermal delivery. The main purpose of this study was to prepare and assess a transdermal formulation of sumatriptan, based on solid lipid nanoparticles (SLNs), to eliminate the undesirable side effects and also improve its percutaneous permeation rate. Topical gel of sumatriptan loaded SLNs was also formulated with respective characteristics assessed. Sumatriptan loaded SLNs were prepared using solvent diffusion/evaporation method. Particle size, entrapment efficiency, in vitro release study and skin permeation analysis of sumatriptan were performed to characterize the prepared SLNs. Then, sumatriptan loaded SLNs were incorporated in a gel formulation as a topical delivery system to assess the percutaneous permeation of sumatriptan. Different compositional and technical variables were considered to optimize the formulation using the design of experiment and drug release performance from the best SLN formulation was evaluated. The results indicated that sumatriptan loaded SLN formulation exhibited increased skin permeation of the drug relative to sumatriptan conventional gel formulation.

Preparation and Structural Characterization of Complex Oxide Eutectic Precursors from Polymer-Salt Xerogels Obtained by Microwave-Assisted Drying.

Sol–gel synthesis is an acknowledged method for obtaining fine inorganic powders of a different nature. Implementation of water-soluble polymers as gel-forming media makes this technique even more readily available, especially in cases where conventional gel formation is suppressed. In polymer–salt solutions, polymers serve as scaffolds for salt constituents’ bulk crystallization. When dried, solid salt particles are deposited on the polymer surface or in polymer matrix pores, which leads to higher grain size uniformity. The present work discusses the effect of drying conditions on phase composition and structure characteristics of complex oxide eutectics in ternary systems, CaO–Al2O3–Y2O3 (CAY) and MgO–Al2O3–Y2O3 (MAY), obtained from polymer–salt compositions based on polyvinyl alcohol (PVA), Na-salt of carboxymethylcellulose (Na-CMC) or polyvinylpyrrolidone (PVP). Microwave-assisted drying proved to be more efficient compared to convective process; however such technique requires careful selection of gel-forming polymer.

In-Gel Isolation and Characterization of Large (and Other) Phages.

We review some aspects of the rapid isolation of, screening for and characterization of jumbo phages, i.e., phages that have dsDNA genomes longer than 200 Kb. The first aspect is that, as plaque-supporting gels become more concentrated, jumbo phage plaques become smaller. Dilute agarose gels are better than conventional agar gels for supporting plaques of both jumbo phages and, prospectively, the even larger (>520 Kb genome), not-yet-isolated mega-phages. Second, dilute agarose gels stimulate propagation of at least some jumbo phages. Third, in-plaque techniques exist for screening for both phage aggregation and high-in-magnitude, negative average electrical surface charge density. The latter is possibly correlated with high phage persistence in blood. Fourth, electron microscopy of a thin section of a phage plaque reveals phage type, size and some phage life cycle information. Fifth, in-gel propagation is an effective preparative technique for at least some jumbo phages. Sixth, centrifugation through sucrose density gradients is a relatively non-destructive jumbo phage purification technique. These basics have ramifications in the development of procedures for (1) use of jumbo phages for phage therapy of infectious disease, (2) exploration of genomic diversity and evolution and (3) obtaining accurate metagenomic analyses.

Apple snail egg perivitellin coloration, as a taxonomic character for invasive Pomacea maculata and P. canaliculata, determined by a simple method

Pomacea canaliculata and P. maculata are freshwater apple snails considered two of the most invasive alien species worldwide. They are expanding their ranges in Asia, Europe and North America, damaging crops, wetland ecosystems and endangering human health. Despite having different invasive potential, they have systematically been misidentified because of their morphological plasticity with highly variable shells, which hampers efforts to manage their spread and impact. Thus, additional work is needed to clarify species boundaries in this group of Pomacea. Here we report a new taxonomic character based on the spectroscopic characteristics of their pigmented perivitellins (egg proteins) and a fast and simple method for measuring it. The egg perivitelline fluid is analyzed via conventional agarose gel electrophoresis and the naturally-colored egg carotenoproteins are extracted, without the need for staining, and analyzed spectrophotometrically. Then, the ratio between two wavelengths (PQ) of the absorbance spectra is calculated. Results can be obtained in less than 24 h. The method was validated in the field by analysing seven populations from Asia (non-native) and South America (native) that had been genetically identified and in which PQ differed consistently between the two species. Eggs are oviposited in conspicuous reddish masses above the waterline, allowing rapid detection and easy collection of samples in the field. This novel tool would be valuable in integrative taxonomic studies to distinguish these two lineages of Pomacea and contribute to our understanding of Pomacea diversity.

Preparation of Nano-Porous Carbon-Silica Composites and Its Adsorption Capacity to Volatile Organic Compounds

Carbon-silica composites with nanoporous structures were synthesized for the adsorption of volatile organic compounds (VOCs), taking tetraethyl orthosilicate (TEOS) as the silicon source and activated carbon powder as the carbon source. The preparation conditions were as follows: the pH of the reaction system was 5.5, the hydrophobic modification time was 50 h, and the dosage of activated carbon was 2 wt%. Infrared spectrum analysis showed that the activated carbon was dispersed in the pores of aerogel to form the carbon-silica composites material. The static adsorption experiments, dynamic adsorption-desorption experiments, and regeneration experiments show that the prepared carbon-silica composites have microporous and mesoporous structures, the adsorption capacity for n-hexane is better than that of conventional hydrophobic silica gel, and the desorption performance is better than that of activated carbon. It still has a high retention rate of adsorption capacity after multiple adsorption-desorption cycles. The prepared carbon-silica composites material has good industrial application prospects in oil vapor recovery, providing a new alternative for solving organic waste gas pollution.

Thermostable Ion Gels for High-Temperature Operation of Electrolyte-Gated Transistors.

High-temperature durability is critical for application of organic materials in electronic devices that operate in harsh environments. In this work, thermostable physically cross-linked polymer electrolytes, or thermostable physical ion gels, were successfully developed using crystallization-induced phase separation of semicrystalline polyamides (PAs) in an ionic liquid (IL). In these ion gels, phase-separated PA crystals act as network junctions and enable the ion gels to maintain their mechanical integrity up to 180 °C. ILs and ion gels are suitable electrolyte candidates for thin-film devices operating at high temperatures because they outperform other electrolytes that use aqueous and organic solvents, owing to their superior thermal stability and nonvolatility. In addition to thermal stability, the PA gels exhibited high ionic conductivity (∼1 mS/cm) and specific capacitance (∼10 μF/cm2) at room temperature; these values increased significantly with increasing temperature, while the gel retained its solid-state mechanical integrity. These thermostable ion gels were successfully used as an electrolyte gate dielectric in organic thin-film transistors that operate at high temperatures (ca. 150 °C) and low voltages (<1 V). The transistors gated with the dielectrics had a high on/off current ratio of (3.04 ± 0.24) × 105 and a hole mobility of 2.83 ± 0.20 cm2/V·s. By contrast, conventional physical ion gels based on semicrystalline polymers of poly(vinylidene fluoride-co-hexafluoropropylene) and polyvinylidene fluoride lost their mechanical integrity and dewetted from a semiconductor channel at lower temperatures. Therefore, these results demonstrate an effective method of generating thermally stable, mechanically robust, and highly conductive solid polymer electrolytes for electronic and electrochemical devices operating in a wide temperature range.

Silica supported SAPO-34 membranes for CO2/N2 separation

Abstract In this work, SAPO-34 membrane was successfully synthesized on silica support by an optimized secondary growth method which combines ageing and rubbing with the use of enhanced synthesis gel. The enhanced synthesis gel was prepared by the addition of SAPO-34 crystals into the synthesis gel. Results of XRD and IR-ATR analysis of SAPO-34 seeds confirmed the formation of SAPO-34 crystal. SEM analysis showed that the crystal has cubic form and the size was about 200–400 nm. The resultant crystals were then used for the preparation of SAPO-34 membrane on the inner surface of the tubular silica support. XRD and XRF analysis showed that SAPO-34 layer was successfully formed on the membrane support with Si/Al ratio of 0.48–0.49. SEM images showed that the optimized secondary growth method could produce continuous and defect-free SAPO-34 membrane (SAPO-34-M2). In contrast, membrane prepared by rubbing method with conventional synthesis gel (SAPO-34-M1) displayed discontinued and defects layer. In single-gas permeation test, SAPO-34-M2 membrane showed two regions of N2 flux indicating the drastic effect of concentration polarization on N2 permeation at higher pressure. The concentration polarization phenomenon resulted in a decrease of CO2/N2 selectivity with increasing transmembrane pressure. It was demonstrated by single-gas permeation test that the SAPO-34-M2 membrane could surpass the Robeson plot (2008) for CO2/N2 separation (permeance = 2.01 × 10−6 mol/m2 s Pa; the highest selectivity = 53). The results showed that the prepared SAPO-34 membrane could be an alternative for CO2/N2 separation.

Accuracy of the QIAxcel Automated System for MIRU-VNTR Genotyping of Mycobacterium tuberculosis in Two Limited Resource Settings.

Mycobacterial interspersed repetitive units variable number tandem repeat (MIRU-VNTR) typing of Mycobacterium tuberculosis complex (MTBC) isolates, based on 24 loci, is still widely used as the standard for routine molecular surveillance of tuberculosis (TB). QIAxcel system is proposed as an affordable tool that could replace conventional gel electrophoresis and provide high concordance with the reference methods regarding MIRU-VNTR typing of MTBC. We aimed to evaluate the QIAxcel accuracy for allele calling of MIRU-VNTR loci in two regional reference laboratories. A total of 173 DNA were used for the study. Results obtained with QIAxcel were compared to the reference results obtained with an ABI 3730 DNA analyzer. In Albania, the overall agreement with the reference method was 97.92%. A complete agreement result was obtained for 17 loci. In Tunisia, the overall agreement with the reference method was 98.95%. A complete agreement result was obtained for 17 loci. Overall agreement in both centers was 98.43%. In our opinion, use of QIAxcel technology has the potential to be reliable, given an optimized algorithm. Inaccuracies in sizing of long fragments should be solved, especially regarding locus 4052.

A novel low-alkali konjac gel induced by ethanol to modulate sodium release

Alcogels have attracted many attentions recently due to their versatile functions and potential applications in developing innovative semi-solid alcohol-containing products. In this study, comparisons were made in the aspect of rheology, physicochemical properties and sodium release between the conventional alkali konjac glucomannan (KGM) gels and alkali KGM alcogels prepared by mixing ethanol with KGM aqueous solution at 0.02 wt%, 0.04 wt% or 0.08 wt% Na2CO3. 20% (v/w) Ethanol could promote the formation of a rigid yet brittle alcogel of KGM with lower dependence of rheological response on frequency and temperature at as low as 0.02 wt% Na2CO3. KGM alcogels were more opaque and constructed by small highly-connected pores, which are 30% smaller in average than those of their counterparts, examined by turbidity and microstructure measurements. Although the swelling ratio of KGM alcogel was only about one third of that of conventional alkali-induced gel, there was about fourfold rise in the amount of Na+ released from alcogels. The release of Na+ could be probably regulated by fine-tuning the macro-properties of alcogels through controlling the alkali concentrations.

Numerical modelling and parametric study of an air-cooled desiccant coated cross-flow heat exchanger

Air-cooled desiccant coated cross-flow heat exchanger (DCCFHE) system provides a simple and effective approach to improve dehumidification performance by using cooling air to remove adsorption heat during adsorption process. In this study, a novel numerical model validated by experimental data was established to predict the performance of a conventional silica gel DCCFHE system. The fin efficiency, as a variable due to the release of adsorption heat, was taken into account in the model. Parametric study for various air velocity and structural parameters was conducted to reveal their effects on the dehumidification performance. Results show that the smaller process air velocity is conducive to improve dehumidification performance, but the performance increases with the increase in cooling air velocity. Compared to the operation case without cooling air, the moisture removal capacity and dehumidification coefficient of performance can obtain about 35% improvement at the cooling air velocity of 1 m/s. The results also indicate that thicker desiccant layer thickness and smaller fin pitch improve moisture removal capacity and dehumidification coefficient of performance but result in greater total pressure drop ΔP, while the performance is insensible to fin thickness and fin height. Besides, effect of heat transfer performance in dehumidification and cooling sides on dehumidification performance was also analyzed. It was found that the heat transfer performance in dehumidification side is the dominant factor affecting dehumidification performance.

Development of Chitosan-Based Hydrogel Containing Antibiofilm Agents for the Treatment of Staphylococcus aureus–Infected Burn Wound in Mice

Methicillin-resistant Staphylococcus aureus (MRSA) is considered a common colonizer of burn wound and accounts for high morbidity and mortality all across the globe. Systemic antibiotic therapy which is generally prescribed for these patients has a number of limitations. These include high drug dose, toxicity, and chances of development of drug resistance. However, local delivery of drug not only addresses these limitations but also provides better efficacy at the site of infection. In the present study, hydrogel preparations were developed for the topical delivery of moxifloxacin for the treatment of S. aureus-infected burn wound. Moxifloxacin was characterized by UV, FTIR, DSC, hot-stage microscopy, NMR, and HPLC and loaded into conventional and Boswellia-containing novel gels. Gels were characterized by visual examination, pH, UV spectroscopy, and release assays. In vivo studies showed that both gels were effective in eradicating the bacteria completely from the wound site when treatment was started during the early stage of infection. On the contrary, delayed treatment of planktonic and biofilm cells with novel gel showed better efficacy as compared with conventional gel in S. aureus-infected burn wound. Histopathological analysis also showed better skin healing efficacy of novel gel than conventional gel. Our results show that moxifloxacin can be efficiently used topically in the management of burn wound infections along with other antibacterial agents. Since biofilm-mediated infections are on the rise especially in chronic bacterial disease, therefore, a preparation containing antibiofilm agent-like Boswellia as one of the excipients would be more meaningful.

Development and Characterization of Niosomal Gel System using Lallementia royaleana Benth. mucilage for the treatment of Rheumatoid Arthritis.

Niosomes structural framework comprises of non-ionic surfactant-based microscopic lamellar structures which carries the potential to sustain the effect of drug from its delivery system. In present work, the attempt was made to identify the effect of different ingredients such as effect of Tweens and natural mucilage of Lallemantia royaleana Benth. on the performance of developed niosomal gel formulations in order to prolong the duration of action of drug and to minimize its side effects of topical conventional drug administration. All Ibuprofen loaded niosomes formulationswere prepared by ether injection method; using cetosteryl alcohol with different variants of Tweens and Spans. Various evaluation parameters were performed to confirm niosome formation. Further, the niosomes were incorporated into gel system and evaluated for in-vitro permeability study (ex-vivo) on excised rat skin by membrane diffusion method and in-vivo study by carrageenan induced rat paw edema model. The best selected niosome formulation F9 gave no sedimentation, layer separation and unchanged particle shapes and thus selected for gel preparation using Lallemantia royaleana Benth. mucilage and carbopol in different ratios. Ex-vivo and in-vivo studies indicated high skin retention and penetration rates within the skin for tests niosomal gel formulations (G1 & G2). The present study suggested that developed topical gel formulation provides enhance permeability and longer duration of drug action over conventional gels.

Preparation of frozen cell-block sections amenableto diagnostic immunocytochemistry: a technical report on cryo-embedded cell-block method.

Modified agarose cell-block (CB) technique can be effectively used to have the CB embedded in the OCT compound for the preparation of frozen CB (F-CB) sections in the same way as in the preparation of frozen sections from cryoembedded fresh tissue samples for the intraoperative consultation. In this report, we demonstrate the amenability of F-CB sections to the diagnostic immunocytochemistry. The pelleted cytologic material was at first compactly embedded in ultralow-gelling temperature agarose gel and then re-embedded in conventional agarose gel. The resulting agarose-embedded cell-pellet was cut in halves so that one half is embedded in OCT compound for cryosectioning on a cryostat, while the other half is reserved for the preparation of paraffin-embedded CB (P-CB). The F-CB sections were comparable to sections cut from the paraffin-embedded CB in terms of the quality of H&E-staining and immunocytochemistry. We suppose this method can also facilitate a rapid quantitative and qualitative assessment of the future P-CB. We have extended this technique to the cryo-embedded cell-block method, inwhich the compact agarose cell pellet is directly embedded in the OCT compound so that the frozen sections can be cut from the cryo-embedded cell block inthe same way as in intraoperative frozen section analysis. In this technical report, we illustrate how the frozen cell blocks (F-CBs) can be effectively prepared not only from liquid-based cytology samples but also from conventional fine-needle aspiration cytology slides.

Formulation and Evaluation of Mupirocin Nimosomal Gel for Topical Drug Delivery System

The present study was to formulate and evaluate the mupirocin niosomal gel using surfactants span 80 &amp; tween 80 for the preparation of niosomes. Mupirocin entrapped niosomes were prepared by ether injection method and transmembrane pH gradient drug uptake process. Niosomes were prepared by altering the ratios between various non-ionic surfactants (span 80 &amp; tween 80) whereas the concentration of cholesterol and drug was kept constant. The prepared niosomes were characterized for size, shape, entrapment efficiency, invitro drug release studies. The highest entrapment efficiency(99.17%) and drug release (96.14%) was obtained for tween 80 (1:5:5) prepared by transmembrane pH gradient method. The best formulation among the two techniques was selected for incorporated into gel formulation. The prepared niosomal gel and plain gel were subjected to evaluation studies like drug content, invitro drug diffusion studies. The studies were demonstrated that niosomal gel was shown beter pharmacological activity than the conventional mupirocin gel. Based on the results it was concluded that niosomal preparations offers more advantageous than the conventional preparations.

Resistance of bonded premolars to four artificial ageing models post enamel conditioning with a novel calcium-phosphate paste.

BackgroundThis in vitro study compares a novel calcium-phosphate etchant paste to conventional 37% phosphoric acid gel for bonding metal and ceramic brackets by evaluating the shear bond strength, remnant adhesive and enamel damage following water storage, acid challenge and fatigue loading. Material and MethodsMetal and ceramic brackets were bonded to 240 extracted human premolars using two enamel conditioning protocols: conventional 37% phosphoric acid (PA) gel (control), and an acidic calcium-phosphate (CaP) paste. The CaP paste was prepared from β-tricalcium phosphate and monocalcium phosphate monohydrate powders mixed with 37% phosphoric acid solution, and the resulting phase was confirmed using FTIR. The bonded premolars were exposed to four artificial ageing models to examine the shear bond strength (SBS), adhesive remnant index (ARI score), with stereomicroscopic evaluation of enamel damage. ResultsMetal and ceramic control subgroups yielded significantly higher (p < 0.05) SBS (17.1-31.8 MPa) than the CaP subgroups (11.4-23.8 MPa) post all artificial ageing protocols, coupled with higher ARI scores and evidence of enamel damage. In contrast, the CaP subgroups survived all artificial ageing tests by maintaining adequate SBS for clinical performance, with the advantages of leaving unblemished enamel surface and bracket failures at the enamel-adhesive interface. ConclusionsEnamel conditioning with acidic CaP pastes attained adequate bond strengths with no or minimal adhesive residue and enamel damage, suggesting a suitable alternative to the conventional PA gel for orthodontic bonding. Key words:Enamel etching, calcium phosphate, bracket bond strength, adhesive residue, enamel damage.

In vitro bond strengths post thermal and fatigue load cycling of sapphire brackets bonded with self-etch primer and evaluation of enamel damage.

This in vitro study compares a self-etch primer (SEP) to an etch-and-rinse (EaR) for bonding sapphire brackets by evaluation of the enamel etch-pattern, shear bond strength, amount of remnant adhesive and enamel surface damage following thermal and fatigue cyclic loading. Ceramic (sapphire) brackets were bonded to 80 extracted human premolars using two enamel etching protocols: conventional EaR using 37% phosphoric acid (PA) gel (control), and a SEP (Transbond Plus). Each group was subdivided into two subgroups (n=20 teeth) according to the time of bracket debonding: after 24 h water storage or following 5000 thermo-cycles plus 5000 cycles fatigue loading, to determine the shear bond strength (SBS), adhesive remnant index (ARI score), with scanning electron microscopy (SEM) evaluation of enamel condition. The control subgroups consistently exhibited significantly higher (p<0.05) SBS mean values (23.4-29.8 MPa) than the SEP subgroups (15.1-22.4 MPa) at both bracket debonding time points. However, the SEP subgroups yielded milder etch-patterns and attained SBS values above the minimum requirement range for clinical performance. In addition, the higher SBS of control subgroups was accompanied with higher ARI scores and enamel damage grades than SEP subgroups as confirmed by SEM. Thermocycling and fatigue significantly reduced the SBS of all subgroups, with a non-significant drop in the amount of adhesive residue or enamel damage. The use of SEP can be a suitable alternative to the conventional PA gel for sapphire bracket bonding as it maintains suitable bond strength and has the potential to produce both less remnant adhesive and enamel damage. Key words:Enamel etching, ceramic brackets, orthodontic bonding, adhesive remnants, enamel damage.

EFFECT OF PLATELET RICH PLASMA-ENRICHED GELFOAM ON CHRONIC TYMPANIC MEMBRANE PERFORATION

Background: Tympanic Membrane (TM) perforation is one of the common reasons of patients’ attending Otolaryngology clinics. Repair of tympanic membrane perforations with most accepted techniques reaches a success rate of over 90%. Platelet-Rich Plasma (PRP) can be defined as an autologous concentration of human platelets in a small volume of plasma. Objective: The aim of this study was to evaluate the effect of PRP-enriched gel foam on the healing of chronic TM perforation in comparison with gel foam alone after myringoplasty. Patients and Methods: In this double-blind randomized clinical trial, 40 patients with chronic tympanic membrane perforations, attending the ENT outpatient clinics of Al-Azhar university hospitals between September, 2017 and May, 2019, they were randomly allocated to two groups; intervention group, underwent myringoplasty with platelet rich plasma (PRP)-enriched gel foams and control group, underwent myringoplasty operation with conventional gel foams alone. Patients were seen 1 month, 3 months and 6 months after surgery. Results: Forty patients, 21 males (52.5%) and 19 females (47.5%) with a mean age of 45.3 ± 11.9 years in intervention, and 43.98 ± 10.8 years in control group underwent analysis. Complete TM healing was seen in 19 (95%) patients in intervention group, and 14 (70%) patients in control group three months after intervention. No complications were seen in intervention group, while three otorrhea cases were recorded for control group in the first follow up after intervention which was resolved by medication. Conclusion: Addition of PRP to conventional gel foams used in TM perforation repair increased the complete healing rate of TM perforation to a significant extent.

EFFECT OF PLATELET RICH PLASMA-ENRICHED GELFOAM ON CHRONIC TYMPANIC MEMBRANE PERFORATION

Background: Tympanic Membrane (TM) perforation is one of the common reasons of patients’ attending Otolaryngology clinics. Repair of tympanic membrane perforations with most accepted techniques reaches a success rate of over 90%. Platelet-Rich Plasma (PRP) can be defined as an autologous concentration of human platelets in a small volume of plasma. Objective: The aim of this study was to evaluate the effect of PRP-enriched gel foam on the healing of chronic TM perforation in comparison with gel foam alone after myringoplasty. Patients and Methods: In this double-blind randomized clinical trial, 40 patients with chronic tympanic membrane perforations, attending the ENT outpatient clinics of Al-Azhar university hospitals between September, 2017 and May, 2019, they were randomly allocated to two groups; intervention group, underwent myringoplasty with platelet rich plasma (PRP)-enriched gel foams and control group, underwent myringoplasty operation with conventional gel foams alone. Patients were seen 1 month, 3 months and 6 months after surgery. Results: Forty patients, 21 males (52.5%) and 19 females (47.5%) with a mean age of 45.3 ± 11.9 years in intervention, and 43.98 ± 10.8 years in control group underwent analysis. Complete TM healing was seen in 19 (95%) patients in intervention group, and 14 (70%) patients in control group three months after intervention. No complications were seen in intervention group, while three otorrhea cases were recorded for control group in the first follow up after intervention which was resolved by medication. Conclusion: Addition of PRP to conventional gel foams used in TM perforation repair increased the complete healing rate of TM perforation to a significant extent.

Synthesis and Characterization of Lead Free Calcium Bismuth Titanate (Ca0.25Bi0.5 TiO3) Piezoelectric Ceramics

Bismuth layer-structured piezoelectric (BLSP) calcium bismuth titanate (Ca0.25Bi0.5TiO3) piezoelectric ceramics have been prepared via a conventional sol gel reaction method by mixing the desired chemicals in stoichiometric amounts. Calcium bismuth titanate (CBT) samples were characterized by means of XRD, SEM and FTIR spectroscopy. X-ray diffraction (XRD) analysis revealed that CBT ceramics exhibit a single phase orthorhombic structure. The SEM images confirm its morphological size ranging from 1.00 to 2.75µm.FTIR analysis reveals that calcium bismuth titanate has been prepared successfully. The photocatalytic removal of Methylene Blue, cadmium (Cd2+) and other toxic heavy metals will be carried out using CBT materials.