Examination of Glass-Fibre Reinforced Composite Dental Fillings

In dentistry, the use of dental fillings is a routine procedure. The use of fillings is a cheap, simple and low-harm dental operation, however, the filling of deep cavities is a difficult task. During this research, three types of fillings were tested: composite fillings bonded directly to the cavity walls, fillings bonded to the cavity walls with a semi-direct method, and composite fillings bonded to the cavity lined with polyethylene fibres. In the course of our examinations, the gaps between the wall of the dental cavity and the dental filling were observed using scanning electron microscopy. The results of these measurements can be used to determine the quality of each type of filling procedure.

Descending necrotizing mediastinitis due to an odontogenic infection: A case report

Descending necrotizing mediastinitis a clinical entity formed by the spreading of cervical infection from the dental and oropharyngeal structures through the deep cavities between the deep fascia on the neck to the mediastinum, pleural and pericardial spaces with necrosis of soft tissue and has a high mortality. Herein we present the case of a 73-year-old admitted to emergency department with septic clinic. The patient was diagnosed with descending necrotizing mediastinitis due to odontogenic infection. Although sternal irrigation, sternal debridement and mediastinal drainage were performed patient was died postoperative third day.

Synthesis of Azacalixarenes and Development of Their Properties

This review focuses on the synthesis, structure, and interactions of metal ions, the detection of some weak interactions using the structure, and the construction of supramolecules of azacalixarenes that have been reported to date. Azacalixarenes are characterized by the presence of shallow or deep cavities, the simultaneous presence of a basic nitrogen atom and an acidic phenolic hydroxyl group, and the ability to introduce various side chains into the cyclic skeleton. These molecules can be given many functions by substituting groups on the benzene ring, modifying phenolic hydroxyl groups, and converting side chains. The author discusses the evidence of azacalixarene utilizing these characteristics.

Phospholipid translocation captured in a bifunctional membrane protein MprF

As a large family of membrane proteins crucial for bacterial physiology and virulence, the Multiple Peptide Resistance Factors (MprFs) utilize two separate domains to synthesize and translocate aminoacyl phospholipids to the outer leaflets of bacterial membranes. The function of MprFs enables Staphylococcus aureus and other pathogenic bacteria to acquire resistance to daptomycin and cationic antimicrobial peptides. Here we present cryo-electron microscopy structures of MprF homodimer from Rhizobium tropici (RtMprF) at two different states in complex with lysyl-phosphatidylglycerol (LysPG). RtMprF contains a membrane-embedded lipid-flippase domain with two deep cavities opening toward the inner and outer leaflets of the membrane respectively. Intriguingly, a hook-shaped LysPG molecule is trapped inside the inner cavity with its head group bent toward the outer cavity which hosts a second phospholipid-binding site. Moreover, RtMprF exhibits multiple conformational states with the synthase domain adopting distinct positions relative to the flippase domain. Our results provide a detailed framework for understanding the mechanisms of MprF-mediated modification and translocation of phospholipids.

Investigation of Surface Quality in Cost of Goods Manufactured (COGM) method of µ-Al2O3 Powder-Mixed-EDM Process on Machining of Ti-6Al-4V

It is very essential to form such high stregth and hard-to-cut materials by using modern machining methods. It is important to introduce the efforts on modification of the process for improving the machining quality. In the present investigation, an effort was made to analyze the effects of micro size aluminium particles mixed dielectric medium under different powder concentration on machining titanium alloy in electro erosion process. The response-surface-methodology(RSM) based algorithm was utilized to analyze the performance measures by considering machinning time with Cost of Goods Manufactured (COGM) method in PMEDM process. It was found that the micron size powders can significantly help to enhance the surface quality of the Ti-6Al-4V surface during machining in EDM process. The presence of carbon, oxygen elements and the formation of surface oxides and carbides has been found due to the decomposition of dielectric fluid in PMEDM process. The lower deep cavities and uniform machining surface have been produced with the aluminum oxide powder EDM process owing to lower surface cracks density, conductivity. To sum up, investigation and comparison of surface scanning showed that this setting has been implied could be considered by the industries needs more precision.

Phospholipid Translocation Captured in a Bifunctional Membrane Protein MprF

As a large family of membrane proteins crucial for bacterial physiology and virulence, the Multiple Peptide Resistance Factors (MprFs) utilize two separate domains to synthesize and translocate aminoacyl phospholipids to the outer leaflets of bacterial membranes. The function of MprFs enables Staphylococcus aureus and other pathogenic bacteria to acquire resistance to daptomycin and cationic antimicrobial peptides. Here we present cryo-electron microscopy structures of MprF homodimer from Rhizobium tropici (RtMprF) at two different states in complex with lysyl-phosphatidylglycerol (LysPG). RtMprF contains a membrane-embedded lipid-flippase domain with two deep cavities opening toward the inner and outer leaflets of the membrane respectively. Intriguingly, a hook-shaped LysPG molecule is trapped inside the inner cavity with its head group bent toward the outer cavity which hosts a second phospholipid-binding site. Moreover, RtMprF exhibits multiple conformational states with the synthase domain adopting distinct positions relative to the flippase domain. Our results provide a detailed framework for understanding the mechanisms of MprF-mediated modification and translocation of phospholipids.

Posterior Restoration Selection Among General Dental Practices in Malaysia: A Preliminary Study

Introduction: Tooth restoration is a common, routine procedure among dentists but still has its own difficulties especially for posterior teeth. As it is a straightforward procedure, some dentists are not aware of the difficulties that may contribute in reducing the longevity of the filling. The aim of the study is to determine the difficulties encountered during and after placement of restorative materials in deep cavities. Materials and methods: Standardized questionnaires were divided randomly among general private dental practitioners in Kuala Lumpur. Chi-square test was used to determine any significant factors associated with difficulties of material placement. Results: This study showed that the most frequent difficulties encountered among practitioners were to obtain good moisture control (39.0%). No significant association was found between obtaining good moisture control and year of clinical experience (p= 0.286) and also place of graduation with the manipulation of the materials (p= 0.542). Conclusion: Dental practitioners claimed that it was difficult to obtain good moisture control in placement of posterior restoration. Thus, it is an obligation of dental practitioners to practice proper isolation and good manipulation of materials on posterior restoration.