Optimization of a metallographic methodology for the study of laser-melted layers of austenitic stainless steel

Introduction: After laser melting during welding and heat treatment processes, the melted zone of the austenitic steel is characterized by a specific fine-grained microstructure formed as a result of the high heating and cooling rates. This causes additional difficulties when the microstructures of the molten zone and the base metal have to be investigated.Aim: The aim of the present paper is to optimize the methodology for preparation of metallographic samples in order to study the microstructure of a laser-melted layer and of a base metal on the same sample.Materials and Methods: Samples of AISI 321 austenitic stainless steel with laser-melted surface layers were ground and polished by a conventional procedure, but etched with aqua regia for different time periods.Results and Discussion: It is found that the microstructure of the laser-melted layers is revealed after a shorter exposure time (2 min) of the reagent, as longer exposure time leads to over-etching. A longer exposure time (5 min) is required to reveal the microstructure of the base metal. Subsequent polishing of the sample results in more obscure structural features.Conclusion: An optimized procedure of a two-stage etching process is proposed. In the first stage, the microstructure of the laser-melted layer is revealed in 2 min exposure time, followed by metallographic studies. After that the second stage continues with additional etching of 3 min to reveal and study the microstructure of the base metal

Methods for obtaining synthetic carbonate apatite for bone regeneration: A review

This review examines the most common methods for the preparation of synthetic carbonate apatite for bone repair in the last ten years. The article is organized into two sections. First, the methods for obtaining powdered carbonate apatite with nanosized particles by wet chemical precipitation reactions are presented, considering the starting reagents and the conditions of the chemical reactions. The second section presents the preparation of carbonate apatite blocks and/or granules by dissolution-precipitation reactions. The transformations occurring in these interactions are systematized according to the type of precursor, soaking solution, and reaction conditions

Antimicrobial therapy: general principles and recommendations for good medical practice. A review

INTRODUCTIONThe terms antimicrobial and antibiotic refer to various therapeutic agents, including antibacterial, antiviral, antifungal, and antiparasitic drugs. Many factors should be considered before prescribing any of these pharmaceutical agents. Some factors are related to the etiologic agents and their behavior, while others are patient-related and depend on individual characteristics.AIMThis review aims to identify the critical aspects of antimicrobial drug therapy, such as appropriate timing, duration, regimens, interpretation of antimicrobial susceptibility testing (AST) results, patient-related factors, and antimicrobial resistance (AMR).MATERIALS AND METHODSAn electronic search was performed in PubMed, Scopus, Web of Science, and Google Scholar, using the following keywords: (((antimicrobial) OR (antibiotic)) AND ((treatment) OR (therapy)) AND (principles) AND ((antimicrobial) AND (resistance))). After evaluation and analysis of the obtained data, 33 articles were included in this study.RESULTS The first step in antimicrobial therapy is selecting an appropriate drug and regimen. The diagnosis is determined by careful analysis of the site of infection, the patient’s general and immune status, and the establishment of the microbial agent. The timing of the antimicrobial therapy depends on the urgency. In high-risk patients, empiric treatment should start immediately after collecting specimens for culture and sensitivity testing. Patient-related factors that should be considered when selecting antimicrobial therapy are hepatic and renal function, age, genetic susceptibility, allergies, pregnancy, lactation, and prior antibiotic use.CONCLUSIONAntimicrobial therapy should be based on selecting appropriate pharmaceutical agents and doses, route of administration, timing, and duration of the treatment. Numerous etiological and patient-related factors should be considered during the treatment. The growing risk of AMR requires more cautious behavior and strict following of the recommendations for good medical practice

Marginal adaptation of ceramic inlays—an in vitro study

Introduction: Class II approximal defects are very common in the clinical practice, in many cases extending subgingivally and beyond the cementoenamel junction (CEJ). For large defects in the posterior region, indirect ceramic restorations provide a better solution than direct composite restorations.Aim: The aim of this experimental in vitro study is to compare the marginal adaptation of hybrid ceramic and lithium disilicate inlays, fabricated using classic and hybrid technique and cemented with two different types of dental cements.Materials and Methods: Forty extracted human molars and premolars were randomly divided into 8 groups and class II cavities (medio-oclusal or disto-oclusal) with the same dimensions were prepared. Hybrid ceramic and lithium disilicate inlays were fabricated according to the manufacturer’s instructions. The marginal gap after cementation was measured using a microscope at 40x magnification.  Results: The lowest cement thickness was registered for Group 4—lithium disilicate inlays, classic technique, cemented with composite cement, closely followed by Group 3—hybrid ceramic inlays, classic technique, cemented with composite cement. The highest mean cement thickness values were registered for Group 1—hybrid ceramic inlays, classic technique, cemented with glass ionomer cement, followed by Group 5—hybrid ceramic inlays, hybrid technique, cemented with glass ionomer cement.Conclusion: Under the limitations of this experimental in vitro study, we can conclude the following: lithium disilicate and hybrid ceramic inlays cemented with composite cement have better marginal adaptation than the ones cemented with glass ionomer cement. Lithium disilicate restorations and inlays without cervical margin relocation (classic technique) have a slightly better marginal fit than hybrid ceramic inlays and restorations with hybrid technique. For a more detailed insight, microleakage evaluation should also be carried out

Afonso Munhoz de Lima, um criptojudeu nas garras da Inquisição do século XVII

IndisponívelIntrodução A Historiografia Inquisitorial é um tema em constante construção no Brasil, e a respeito da atuação do Tribunal do Santo Ofício na Amazônia ainda há várias lacunas a serem preenchidas. Uma delas é sobre a atuação e presença da comunidade cristã-nova, sendo tema pouco explorado na historiografia sobre a região. É preciso conhecer sobre essa comunidade, que foi influente na história colonial tanto a nível político quanto econômico, os documentos inquisitoriais são fontes riquíssimas para se compreender a atuação e trajetória desses sujeitos históricos durante o período colonial...1Nã

Ranula as a Complication of Dental Implant Therapy: A Case Report and Systematic Review

Introduction. Ranulas are pseudocysts caused by saliva retention or extravasation from the sublingual or submandibular gland. Trauma is believed to be the most common cause of ranula formation, but it can also result from ductal obstruction or congenital malformation. Ranulas are relatively rare to encounter in clinical practice and infrequently associated with dental implant therapy. Methods. This study presents a case report of ranula formation in the right sublingual gland in association with dental implant therapy. In addition, a systematic review of case reports on this problem was conducted. The study aimed to identify the etiology of ranula development during/after implant therapy in patients undergoing implant-based dental rehabilitation. An advanced search was conducted on October 22, 2024, using the Web of Science, Scopus, and PubMed databases. The exported data demonstrated that reports on ranula formation were scarce. Four studies met the eligibility criteria; three were included in this analysis after quality assessments. Results. It was found that procedures leading to ranula formation were dental implant surgery in the mandible with perforation of the lingual plate and laceration of the sublingual or submandibular gland and placement of implant-retained overdentures causing duct obstructions. The treatment approaches included salivary gland excision (when the gland was traumatized) and duct marsupialization (when the ducts were obstructed). In the case report presented in this study, the etiology was attributed to soft tissue trauma caused by the implant drill during surgery. Different treatment modalities were used, including marsupialization, incision, and drainage. However, all led to a recurrence, and the gland was completely removed. Conclusions. Ranula formation has rarely been associated with dental implant therapy, with only a few reports in the literature. This case report suggests that ranulas may develop during implant placement, even if the lingual plate is not perforated. Such complications can be prevented through meticulous treatment planning and precise surgical techniques. The treatment of choice for ranulas remains sialadenectomy, especially in patients with a history of recurrence

Cluster analysis of consumers of companies in the fitness industry of the Vologda region

The article is devoted to the study of consumer behavior in the Vologda regional sector of the health and beauty sector (H&amp;B). The main components of the industry of H&amp;B are the following sub-sectors fitness industry, dietary supplements, nutrition, preventive services, remedial therapy, cosmetics and perfumery, the production of eco-bio-protective equipment. This article presents the results of the analysis of consumer behavior in the Vologda regional sector of the industry, reveals its social significance, as well as the significance of the personnel training process. This article provides evidence-based reasoning that when consumers are divided into several clusters according to socio-demographic and behavioral characteristics. These two hypotheses were experimentally confirmed in the Vologda regional market: 4 clusters were identified, in which, in turn, 11 segments were identified by frequency and duration of consumption of goods and services by H&amp;B.</jats:p