Mathematical Modeling of the Relation between Basic Chemical Elements and Soil Properties

This paper presents mathematical modeling of the relation between basic chemical elements and soil properties. An overview of the basic chemical elements and properties of the soil is presented. An approach is proposed to conduct an experimental study of the impact of basic chemical elements and soil properties. Statistical methods are used for data processing. Mathematical models for relation between basic chemical elements and soil quality indicators are developed. Mathematical models for indirect determining the content of basic chemical elements by measuring the main soil indicators are analyzed

Prognostic factors for anastomotic insufficiency in elective colorectal surgery

Introduction: Anastomotic insufficiency is a severe, potentially fatal complication of colorectal surgery. Its frequency, according to different authors, reaches up to 20%. It is related to two main types of risk factors: associated with the patient and associated with the therapeutic approach.Aim: The aim of the study is to determine prognostic factors for anastomotic insufficiency. The collected data from patients operated on for a period of 5 years (2013-2017) in the Second Surgery Clinic, Alexandrovska University Hospital, Sofia, were analyzed.Materials and Methods: A total of 158 patients undergoing elective colorectal surgery have been retrospectively included. These on emergency, non-proven malignancies and with preoperative haemotransfusion were excluded from the study. All patients were evaluated by age, gender, BMI, ASA score, Charlson Comorbidity Score, localization, TNM stage and histological type. The surgical approach and the method of resection were determined. The postoperative period and complications were classified according to the Clavien-Dindo scale. The number of leukocytes, platelets, RDW, CRP and albumin were examined preoperatively, and on the day 1 and day 4, in the early postoperative period.Results: The average age of the patients was 67 (29-87). Of these, 100 (63.3%) were men, and 58 (36.7%) are women. The mean BMI was 27.1 (23-33). A total of  78.9% of the operated patients weree in TNM stage II and III. Histologically, 77.8% were moderately differentiated adenocarcinomas. The mean Charlson Comorbidity Score for the sample was 7.1 (range: 2-13), and the ASA score was 3 (2-4). The rectum was the most common localization - 40.1%, followed by right colon 22.8%, and the sigmoid colon 20.9%. Over the review period, most resections were conventional, with only 15.2% laparoscopic approach. The operations performed were right hemicolectomy - 36 (22.8%), left hemicolectomy -15 (9.5%), segmental resection - 38 (24.1%), total colectomy - 4 (2.5%) resection of the rectum - 44 (27.9%), and other - 21 (13.3%). In 12 (7.6 %) of the patients insufficiency was reported between day 2 and day 3, postoperatively. Five of them were treated conservatively and the other six were reoperated. Seven of the insufficiencies were after anterior resection of the rectum, 2 were after left hemicolectomy, 1 after resection of the sigmoid colon, one was after right hemicolectomy, which had been treated conservatively. The mean postoperative period of patients with insufficiency was 22 days (range: 9-45). For patients without complications, the postoperative period was 9.4 days (range: 4-21) and there was a strict statistical difference (P <0.05). All patients experienced an increase in leukocyte counts postoperatively, albumin drop, increased CRP and ESR. The mean platelet counts depended on the presence of insuffiency.Conclusion: The anterior resection, which is associated with technically more difficult anastomosis and neoadjuvant radiotherapy is a potential risk factor for anastomotic insufficiency. The use of blood parameters in the postoperative period allows early diagnosis of the complication and possible change of the therapeutic strategy

Matrix Metalloproteinases in Oral Health—Special Attention on MMP-8

Matrix metalloproteinases (MMPs) are a large family of Ca2+ and Zn2+ dependent proteolytic enzymes, able to cleave the various components of the extracellular matrix (ECM), as well as a range of other regulatory molecules. Several reports have proven the important role of both MMPs and their endogenous inhibitors, TIPMs, in oral health, the initial development of the tooth, and during enamel maturation. In this mini-review, we aim to summarize the literature information about the functions of MMPs, paying more attention to MMP-8 (collagenase-2 or neutrophil collagenase) in the development and progression of periodontitis, peri-implantitis, and carious lesions. We also emphasize the role of particular gene variants in MMP8 as predisposing factors for some oral diseases

Plastic Degradation by Extremophilic Bacteria

Intensive exploitation, poor recycling, low repeatable use, and unusual resistance of plastics to environmental and microbiological action result in accumulation of huge waste amounts in terrestrial and marine environments, causing enormous hazard for human and animal life. In the last decades, much scientific interest has been focused on plastic biodegradation. Due to the comparatively short evolutionary period of their appearance in nature, sufficiently effective enzymes for their biodegradation are not available. Plastics are designed for use in conditions typical for human activity, and their physicochemical properties roughly change at extreme environmental parameters like low temperatures, salt, or low or high pH that are typical for the life of extremophilic microorganisms and the activity of their enzymes. This review represents a first attempt to summarize the extraordinarily limited information on biodegradation of conventional synthetic plastics by thermophilic, alkaliphilic, halophilic, and psychrophilic bacteria in natural environments and laboratory conditions. Most of the available data was reported in the last several years and concerns moderate extremophiles. Two main questions are highlighted in it: which extremophilic bacteria and their enzymes are reported to be involved in the degradation of different synthetic plastics, and what could be the impact of extremophiles in future technologies for resolving of pollution problems

An Assessment of the Functioning of Shopping Centres in Central-Eastern Europe on the Example of “Posnania Mall” in Poznań (Poland) and “Grand Mall” in Varna (Bulgaria)

The article explores the issue of the function of shopping centres, in particular the analysis of the impact of their presence on society and the local development of cities and regions. Regarding the empirical aspect, the examples of Poznań (Poland) and Varna (Bulgaria) will be presented. As a result of similar socio economic conditions and joining the European Union at almost the same moment, all comparative studies reflecting preferences and market reactions seem both viable and interesting. In addition, the two cities chosen for the studies occupy a similar place in the hierarchy of the settlement network in their countries. They are large, well developed centres that attract the attention of investors from various segments of the real estate market. The research is part of the modelling of preferences of shopping centre customers areas, which in particular supports the investment decisions of developers operating in the analysed real estate market, and at the same time permits a diagnosis of social satisfaction. A derivative of the research is also the reconstruction of the effects of the functioning of largescale shopping malls in two Central Eastern European countries

Development and validation of HPLC-DAD methodology for simultaneous qualitative and quantitative determination of thirteen substances with a steroid structure

AbstractUsing supplements in different sports is a common practice for many athletes. Unfortunately, the growth of this market has entailed some speculations, such as the addition of excessive doses of potentially toxic ingredients. Sometimes the doses listed on the package do not correspond to the real content. Some nutritional supplements on sale may contain undeclared ingredients. Some of those supplements are prohibited substances according to different regulations. Herein, a simple HPLC/DAD procedure that is easy to apply in conventional laboratory practice was developed for the simultaneous determination of 13 substances with steroid structure in nutritional supplements for sport: testosterone, testosterone propionate, testosterone enanthate, methyltestosterone, nandrolone, nandrolone propionate, nandrolone decanoate, methandienone, androstenedione, trenbolone, trenbolone acetate, trenbolone enanthate and boldenone undecylenate. The methodology includes gradient elution with mobile phase A: MeOH:ddH2O (55:45) and mobile phase B: 100% MeOH in a standard HPLC system containing a Halo 90 Å, C18 (150 x 4.6 mm, 2.7 µm) column, flow rate 0.6 mL/min, UV wavelength of 254 nm, temperature of 40 °C and 20 μL injection volume. The developed methodology was validated according to the corresponding official documents. The key parameters used for the selection of the optimal HPLC conditions were the ability of the mobile phase and solvents to be used with both an HPLC/MS and a GC/MS chromatographic system. The obtained total run time, the reproducibility of the retention times, the separation of all peaks and peak characteristics meet all requirements

Intraoperative Radiotherapy with Balloon-Based Electronic Brachytherapy System—A Systematic Review and First Bulgarian Experience in Breast Cancer Patients

(1) Background: We aimed to analyze currently available studies with intraoperative radiotherapy (IORT) as a choice of treatment where the Xoft Axxent® electronic brachytherapy (eBx) system was used as a single-dose irradiation and an exclusive radiotherapy approach at the time of surgery in patients with early breast cancer (EBC). We also compared the results of the systematic review to the Bulgarian experience. (2) Methods and Materials: We performed a systematic review of the studies published before February 2021, which investigate the application of a single-fraction 20 Gy radiation treatment, delivered at the time of lumpectomy in EBC patients with the Xoft Axxent® eBx System. A systematic search in PubMed, Scopus, and ScienceDirect was performed. The results are reported following the PRISMA guidelines. The criteria on patients’ selection for IORT (the additional need for EBRT), cosmetic outcomes, and recurrence rate from the eligible studies are compared to the treatment results in Bulgarian patients. (3) Results: We searched through 1032 results to find 17 eligible studies. There are no published outcomes from randomized trials. When reported, the cosmetic outcomes in most of the studies are defined as excellent. The observed recurrence rate is low (1–5.8%). Still, the number of patients additionally referred to postoperative external breast radiotherapy (EBRT) is up to 31%. Amongst the 20 patients treated in Bulgaria, the cosmetic outcomes are also evaluated as excellent, five of which (25%) are referred for EBRT. Within median follow-up of 39 months, there was one local and one distal recurrence. (4) Conclusions: Current evidence demonstrates the Xoft Axxent® eBx system as a safe and feasible technique for IORT delivery in EBC patients. There are no randomized controlled trials conducted at this time point to prove its long-term effectiveness. Better patient selection and a reimbursement strategy have to be proposed to extend the application of this technique in Bulgaria

50 години Катедра „Социална медицина и организация на здравеопазването`

22 Май 201

Abstracts Of The Proceedings And The Posters From The Third Scientific Session Of The Medical College Of Varna

October 2-3, 201