Radiation Characteristic Improvement of X-Band Slot Antenna Using New Multiband Frequency-Selective Surface

A new configuration of frequency-selective surfaces (FSSs) is designed and presented with multiresonance characteristics which covers all of the frequency domain of X-band from 8 to 12 GHz. The proposed FSS comprises three conductor-based split ring resonators, connected together. In this design, two unit cells of the FSS with different lengths are employed side by side to design the FSS. The FSS is used to enhance the gain of the new designed triangle slot antenna at X-band. The proposed FSS is analyzed by using reflected-wave unit-cell box method. The single, double, and array of the FSS cells are studied. Next, the designed FSS along with the antenna is analyzed. The measurement and simulated results of the impedance and radiation characteristics, especially the increment of the gain, are presented

Novel coronavirus (COVID-19) and dentistry–A comprehensive review of literature

The novel coronavirus (COVID-19) pandemic has become a real challenge for healthcare providers around the world and has significantly affected the dental professionals in practices, universities and research institutions. The aim of this article was to review the available literature on the relevant aspects of dentistry in relation to COVID-19 and to discuss potential impacts of COVID-19 outbreak on clinical dentistry, dental education and research. Although the coronavirus pandemic has caused many difficulties for provision of clinical dentistry, there would be an opportunity for the dental educators to modernize their teaching approaches using novel digital concepts in teaching of clinical skills and by enhancement of online communication and learning platforms. This pandemic has also highlighted some of the major gaps in dental research and the need for new relevant knowledge to manage the current crisis and minimize the impact of such outbreaks on dentistry in the future. In conclusion, COVID-19 has had many immediate complications for dentistry of which some may have further long-term impacts on clinical practice, dental education and dental research

Three-Dimensional \u3cem\u3eIn Vitro\u3c/em\u3e Oral Mucosa Models of Fungal and Bacterial Infections

Oral mucosa is the target tissue for many microorganisms involved in periodontitis and other infectious diseases affecting the oral cavity. Three-dimensional (3D) in vitro and ex vivo oral mucosa equivalents have been used for oral disease modeling and investigation of the mechanisms of oral bacterial and fungal infections. This review was conducted to analyze different studies using 3D oral mucosa models for the evaluation of the interactions of different microorganisms with oral mucosa. In this study, based on our inclusion criteria, 43 articles were selected and analyzed. Different types of 3D oral mucosa models of bacterial and fungal infections were discussed in terms of the biological system used, culture conditions, method of infection, and the biological endpoints assessed in each study. The critical analysis revealed some contradictory reports in this field of research in the literature. Challenges in recovering bacteria from oral mucosa models were further discussed, suggesting possible future directions in microbiomics, including the use of oral mucosa-on-a-chip. The potential use of these 3D tissue models for the evaluation of the effects of antiseptic agents on bacteria and oral mucosa was also addressed. This review concluded that there were many aspects that would require optimization and standardization with regard to using oral mucosal models for infection by microorganisms. Using new technologies—such as microfluidics and bioreactors—could help to reproduce some of the physiologically relevant conditions and further simulate the clinical situation. Impact statement Tissue-engineered or commercial models of the oral mucosa are very useful for the study of diseases that involve the interaction of microorganisms and oral epithelium. In this review, challenges in recovering bacteria from oral mucosa models, the potential use of these three-dimensional tissue models for the evaluation of the effects of antiseptic agents, and future directions in microbiomics are discussed

Implant soft-tissue attachment using 3D oral mucosal models—a pilot study

Purpose: The aim of this study was to investigate soft-tissue attachment to different metal, ceramic, and polymer implant surfaces using an inflamed, three-dimensional (3D), tissue-engineered, human oral mucosal model, as well as multiple-endpoint qualitative and quantitative biological approaches. Methods: Normal human oral fibroblasts, OKF6/TERT-2 keratinocytes and THP-1 monocytes were cultured, and full-thickness, 3D oral mucosal models were engineered inside tissue culture inserts. Sand-blasted and acid-etched (SLA) and machined (M) titanium–zirconium alloy (TiZr; commercially known as Roxolid; Institut Straumann AG, Switzerland), ceramic (ZrO2), and polyether ether ketone (PEEK) rods (Ø 4 mm × 8 mm) were inserted into the center of tissue-engineered oral mucosa following a Ø 4mm punch biopsy. Inflammation was simulated with addition of the lipopolysaccharide (LPS) of Escherichia coli (E. coli) and tumor necrosis factor (TNF)-alpha to the culture medium. Implant soft-tissue attachment was assessed using histology, an implant pull-test with PrestoBlue assay, and scanning electron microscopy (SEM). Results: Inflamed, full-thickness, 3D human oral mucosal models with inserted implants were successfully engineered and histologically characterized. The implant pull-test with PrestoBlue assay showed higher viability of the tissue that remained attached to the TiZr-SLA surface compared to the other test groups. This difference was statistically significant (p < 0.05). SEM analysis showed evidence of epithelial cell attachment on different implant surfaces. Conclusions: The inflamed, 3D, oral mucosal model has the potential to be used as a suitable in vitro test system for visualization and quantification of implant soft-tissue attachment. The results of our study indicate greater soft tissue attachment to TiZr-SLA compared to TiZr-M, ceramic, and PEEK surfaces

Thoracic Pneumorrhachis in Patient with Lumbar Fractures; a Case Report

Pneumorrhachis as a relatively rare condition may be an indication of substantial intra-spinal column injury. Here we report a 39-year-old man was admitted because of low back pain and dyspenea after locating between motor vehicle and wall three days before admission. On arrival, physical exams and vital signs were normal. Computed tomography (CT) scan showed bilateral pleural effusion, fracture of ribs number 8, 9 and 10 in lower left side of thorax, fracture of vertebra in L2-L4, and air bubbles in upper thoracic spinal canal.

Relationship between Color and Translucency of Multishaded Dental Composite Resins

The aim of the present study was to compare the translucency of different shades of two highly aesthetic multilayered restorative composite resins. In total nine shades from Esthet.X and ten shades from Filtek Supreme composite resins were chosen. Discs of each shade were prepared (N = 3) and light-cured. Total and diffuse transmittance values for each sample were measured. Statistical analysis showed that the opaque dentine shades of both composites were the least translucent and the enamel shades had the highest translucency. There was a significant decrease in translucency from A2 to C2 of regular body shades and also from A4 to C4 of opaque dentine shades of Esthet.X composite resin. Grey enamel shade had a significantly higher diffuse translucency compared to clear and yellow enamel shades. There was a significant decrease in translucency from A2B to D2B and also in diffuse translucency from A4D to C6D shades of Filtek Supreme composite resin. It can be concluded that the color of the composite resins tested in this study had a significant effect on their translucency. Information on the translucency of different shades of composite resins can be very useful for the clinicians in achieving optimal esthetic restorative outcome

Effects of electronic cigarette liquid on monolayer and 3D tissue-engineered models of human gingival mucosa

Background. There is limited data available on potential biological effects of E-cigarettes on human oral tissues. The aim of this study was to evaluate the effects of E-cigarette liquid on the proliferation of normal and cancerous monolayer and 3D models of human oral mucosa and oral wound healing after short-term and medium-term exposure. Methods. Normal human oral fibroblasts (NOF), immortalized OKF6-TERET-2 human oral keratinocytes, and cancerous TR146 keratinocyte monolayer cultures and 3D tissue engineered oral mucosal models were exposed to different concentrations (0.1%, 1%, 5% and 10%) of E-cigarette liquid (12 mg/ml nicotine) for 1 hour daily for three days and for 7 days. Tissue viability was monitored using the PrestoBlue assay. Wounds were also produced in the middle surface of the monolayer systems vertically using a disposable cell scraper. The alterations in the cell morphology and wound healing were visualized using light microscopy and histological examination. Results. Statistical analysis showed medium-term exposure of TR146 keratinocytes to 5% and 10% E-liquid concentrations significantly increased the viability of the cancer cells compared to the negative control. Short-term exposure of NOFs to 10% E-liquid significantly reduced the cell viability, whereas medium-term exposure to all E-liquid concentrations significantly reduced the NOF cells’ viability. OKF6 cells exhibited significantly lower viability following short-term and mediumterm exposure to all E-cigarette concentrations compared to the negative control. 3D oral mucosal model containing normal oral fibroblasts and keratinocytes showed significant reduction in tissue viability after exposure to 10% E-liquid, whereas medium-term exposure resulted in significantly lower viability in 5% and 10% concentration groups compared to the negative control. There was a statistically significant difference in wound healing times of both NOF and OKF6 cells after exposure to 1%, 5% and 10% E-cigarette liquid. Conclusion. Medium-term exposure to high concentrations of the E-cigarette liquid had cytotoxic effects on normal human oral fibroblasts and OKF6 keratinocytes, but a stimulatory cumulative effect on the growth of cancerous TR146 keratinocyte cells as assessed by the PrestoBlue assay and histological evaluation of 3D oral mucosal models. In addition, E-liquid exposure prolonged the wound healing of NOF and OKF6 oral mucosa cells

Biomodification of a class-v restorative material by incorporation of bioactive agents

Restoring subgingival class-V cavities successfully, demand special biological properties from a restorative material. This study aimed to assess the effects of incorporating bioactive materials to glass ionomer cement (GIC) on its mechanical and biological properties. Hydroxyapatite, chitosan, chondroitin sulphate, bioglass, gelatine and processed bovine dentin were incorporated into a GIC restorative material. Compressive strength, biaxial flexural strength (BFS), hardness, setting and working time measurements were investigated. Biocompatibility of the new materials was assessed using both monolayer cell cultures of normal oral fibroblasts (NOF) and TR146 keratinocytes, and a 3D-tissue engineered human oral mucosa model (3D-OMM) using presto-blue tissue viability assay and histological examination. Significant reduction in the compressive strength and BFS of gelatine-modified discs was observed, while chondroitin sulphate-modified discs had reduced BFS only (p value > 0.05). For hardness, working and setting times, only bioglass caused significant increase in the working time. NOF viability was significantly increased when exposed to GIC-modified with bovine dentine, bioglass and chitosan. Histological examination showed curling and growth of the epithelial layer toward the disc space, except for the GIC modified with gelatine. This study has highlighted the potential for clinical application of the modified GICs with hydroxyapatite, chitosan, bioglass and bovine dentine in subgingival class-V restorations

Knowledge and Attitude Regarding Organ Donation among Relatives of Patients Referred to the Emergency Department

Introduction: Organ donation is one of the surviving procedures which can increase the life expectancy of end-stage patients. Inappropriate beliefs and attitude of individuals to organ donation, their poor knowledge, and the socio-economic level are one of the most important barriers for organ donation. Therefore, here knowledge and attitude levels among relatives of trauma patients regarding organ donation were evaluated. Methods: This cross-sectional study was done on relatives of trauma patients referred to the emergency department of Sina Hospital, Tabriz, Iran, through 2013 to 2014. The questionnaire included parts of demographic data and socio-economic situations as well as status of knowledge and attitude regarding organ donation. A score between 0-7 was belonged to each person based on his/her level of knowledge. Attitude level had a score between 0-12. Chi- square, Fisher, and Mann–Whitney U test were performed to assess the relation between demographic variables and the level of knowledge and attitude. P&lt;0.05 was considered as a significant level. Results: 79 persons (57.1% male) with the mean age of 31.3±11.3 years were evaluated. 57 (73.1%) of subjects agreed with organ transplant. The main causes of disagreement among relatives regarding organ donation were dissatisfaction of the donor's relatives (25%) and religious issues (15%). 49 (62.02%) studied people had inappropriate attitude and 27 (34.2%) ones had good knowledge. male gender (OR=5.87; 95%CI: 3.32-8.42; p=0.001) and self-employed job (OR=7.78; 95%CI: 4.64-10.92; p=0.001) are independent factors associated with poor knowledge about organ donation. Self-employed job (OR=3.86; 95%CI: 1.41-6.11; p=0.009) and poor knowledge (OR=15.3; 95%CI: 9.03-21.57; p&lt;0.001) were related to inappropriate attitude toward organ donation. Conclusion: The present study showed that 73.1% of participants agreed with organ donation. The major causes of disagreements were dissatisfaction of other relatives and religious beliefs. 62.0% of the studied people had positive view regarding organ donation and 34.2% of them well-informed about. The most important causative factors for poor knowledge in this context were male gender and self-employed occupation. In addition, poor knowledge and self-employed job were two factors associated with inappropriate attitude toward organ donation

Epidural Hematoma Following Hemodialysis in a Methanol Poisoned Pa-tient; a Case Report

Brain injury associated with methanol toxicity can be ischemic, necrotic or hemorrhagic in nature. It most commonly affects the putamenal area bilaterally, but can be seen in other locations. This report describes a 22-year-old intoxicated patient who developed an epidural hematoma following hemodialysis. Heparinization during hemodialysis may contribute to cerebral hemorrhagic complications in methanol poisoning. In addition, a history of head trauma may raise the incidence of post-hemodialysis hemorrhagic brain insults. Heparin-free dialysis or peritoneal dialysis can be a good option in these cases