A digital system for accurate time sector division of a spin stabilized vehicle

Digital system for accurate time sector division of spin stabilized vehicle as used on Pioneer space probe

Cosmic ray tables - Asymptotic directions, variational coefficients and cut-off rigidities IQSY instruction manual no. 10

Cosmic ray deflections in geomagnetic field, variational coefficients, and diurnal intensity variations - table

Surface modifications of dental implants: An overview

Osseointegration is the key for long term success of endosseous dental implants. Implant surface properties like surface roughness, surface topography, surface energy and surface composition are the major characters that influence the process of osseointegration. Several methods have been used to optimise implant surface roughness to increase surface area thereby improving the process of osseointegration. Blasting using alumina and titanium dioxide, acid treatment, anodization, and laser peeling are some of the subtractive methods used to optimize implant surface roughness. Additive methods used to coat HA onto the surface of endosseous implants include plasma sprayed HA, vacuum deposition technique, sol-gel and dip coating method, electrolytic process and nano-HA coating. Recently, biomimetic implant surfaces are produced with calcium phosphate coatings under physiological conditions. These coatings are also capable to act as vehicles for osteogenic agents like BMPs, GDFs and  biologically active drugs like bisphosphonates, gentamicin, tetracycline, etc.,. The methods used for surface modifications of endosseous dental implants are vast and continuously evolving with the recently developed technologies. This article gives an overview on various surface modifications and current trends followed in the field oral implantology

Self-sealing resin fixators in dentistry

Fixed indirect restorations bond to the prepared tooth surfaces with the use of a variety of luting agents depending upon the purpose of that rehabilitation. Success and failures of these restorations have been attributed to the quality of their bond with the tooth substrate. However, the advent of resin-based and self-adhesive resin luting agents have greatly changed this equation by altering the conventional bonding mechanisms and the durability of bond. The limited literature details of these self-adhesive resin luting agents require further exploration for the benefit of dental professionals. This review provides an overview of the composition, chemical interactions, favourable and unfavourable properties to be known for improving the scope of their utilization in dentistry

Corrosion in Titanium dental implants – a review

Titanium (Ti) is the most widely used biomaterial for dental implants as it exhibits excellent mechanical properties and biocompatibility. The biocompatibility of titanium is related to thin, protective surface titanium dioxide (TiO2) layer, which forms a boundary at the implant-biological medium interface, reducing its reactivity with the surrounding biological environment and prevents corrosion. However, the metallic materials used as implants are susceptible to corrosion due to variations in the internal electrolyte environment. The surface oxide layer can be destroyed during insertion of implant or micro-motion between implant and bone under loading conditions. The localized destruction causes corrosion of the implant and induces leak of metallic particles or ions into surrounding tissues. The presence of metallic particles in peri-implant soft and hard tissues may be due to frictional wear or corrosion, or simultaneous occurrence wear and corrosion which is known as tribocorrosion. The released metal ions may remain in the intercellular spaces near the site where they were released or may be taken up by macrophages, or they can migrate systemically. This review article highlights various aspects of corrosion, biological response to corrosion products and prevention of corrosion of titanium dental implants

Do mutual funds have consistency in their performance?

Using a comprehensive data set of 714 Chinese mutual funds from 2004 to 2015, the study investigates these funds’ performance persistence by using the Capital Asset Pricing model, the Fama-French three-factor model and the Carhart Four-factor model. For persistence analysis, we categorize mutual funds into eight octiles based on their one year lagged performance and then observe their performance for the subsequent 12 months. We also apply Cross-Product Ratio technique to assess the performance persistence in these Chinese funds. The study finds no significant evidence of persis- tence in the performance of the mutual funds. Winner (loser) funds do not continue to be winner (loser) funds in the subsequent time period. These findings suggest that future performance of funds cannot be predicted based on their past performance.info:eu-repo/semantics/publishedVersio

The abnormal electrical and optical properties in Na and Ni codoped BiFeO3 nanoparticles

published_or_final_versio

Disinfection of impression materials: A comprehensive review of disinfection methods

Impression making is one of the most common procedures that are performed by dentists in day-to-day practice. These impressions can act as vehicles of transmission and carry various types of microorganisms, which further cause diseases like Hepatitis B, C, HIV, Tuberculosis etc. This contamination and cross contamination of microorganisms can be prevented by disinfecting the impressions immediately after removing from the mouth and label them as disinfected. Usually the impressions are placed under running water to remove saliva and blood, but this will eliminate the disease-causing microorganisms, so a standard protocol to disinfect the impressions and casts should be known to dentists and dental personnel. Various methods of impression disinfection like chemical disinfection, Microwave, Autoclave, Ultraviolet radiation have been described in literature having their own advantages, disadvantages and effects on impression material and casts. Recently antimicrobials and nanoparticles have been incorporated into the impression material itself to make it self- disinfecting. This will not only disinfect the impression material from inside but also disinfect the impressions from the time it is inserted in patient’s mouth.  A broad search on the literature available was performed to provide knowledge about mechanism of action, concentration of usage along with commercial preparations available of different disinfectants. This review article will enhance the knowledge and improve the behavior of dental health care workers about impression disinfection

Prosthodontic rehabilitation of a mucormycosis patient: a case report

Maxillofacial defects can result from congenital disabilities, cancer surgery, trauma, infection, or disease. Facial deformities can affect how a person looks, feels about themselves, and interacts with others. It can significantly impair phonetics, mastication, and deglutition and cause facial deformation. Maxillectomy due to mucormycosis is one such maxillofacial defect and it becomes essential to rehabilitate these cases with modified techniques based on the extension of intraoral defect, the severity, the degree of resection, the type of mucormycosis, the stability of lesions over time, the presence of contiguous disease, the accessibility of dental and prosthetic resources, and patient expectations. The prosthetic reconstruction with a maxillofacial prosthesis can restore function and appearance, comfort, and quality of life. The prosthesis should be simple to handle, easy to maintain, biocompatible, light in weight, and convenient for future adjustments. The maxillofacial surgeon, oncologist, and reconstructive dentist should work together to develop a treatment plan based on these considerations. This case report provides the current treatment options for these patients and rehabilitation of the defect. It also discusses the issues that need to be addressed during the planning of prosthetic treatment and highlights some challenges the clinicians face in providing prosthetic treatment for mucormycosis patients

The effect of Fit-checking material and various subsequent cleaning methods on the wettability of the dentin surface: an in vitro study

Background: GC Fit-checker is a modified polyvinyl siloxane impression material exclusively used to check the internal fit and improve the marginal fit of indirect restorations. An unpolymerized organic film is known to be leftover on the bonding surfaces after the silicone disclosing procedure. Residual silicone film being hydrophobic may alter the wettability of the cement to the tooth/metal surface, thus having a detrimental effect on the bond strength and retention of the restoration.   Aim: This study aimed to evaluate the wetting of luting liquid (GIC) to tooth dentin surface after application of Fit-checker and evaluate the efficiency of various surface treatments in removing the residual silicone film. Materials and Methods: Extracted human molars were mounted on the acrylic block, and the tooth occlusal surface was ground flat till the dentin exposure. All the specimens were assigned into five groups: Group 1: without application of Fit-checker (control group); Group 2: without any surface treatment after peeling off Fit-checker; Group 3: surface treatment with wet pumice; Group 4: 37% phosphoric acid treatment; Group 5: 10% polyacrylic acid treatment. Later, Type 1 Glass Ionomer Cement (GIC) liquid drop was placed on the dentin and photographs were made horizontally using a standardized procedure. Contact angles were measured using AUTOCAD software. Obtained values were statistically analyzed using the One-way ANOVA test and Tukey’s Post hoc test. Samples of each group were examined using the scanning electron microscope. Results: Statistically significant difference was observed among all the groups except between Group 4 and Group 2 (p > 0.05). SEM images of various groups showed a significant difference in roughness patterns. Conclusion: Surface treatment with pumice and the rotary brush was an effective method among the three in cleaning the residual silicone film