Publications by authors named "Marin Marinov"

Open surgical repair of abdominal aortic aneurysm (AAA) is often regarded as a near-permanent operation with little long-term complications. Reported herein is a case of delayed rupture of an enlarging AAA sac after open repair requiring re-exploration in a patient presenting with flank pain and ipsilateral hydronephrosis. The natural history of a large, excluded aneurysm sac after open AAA repair, hypothesized etiology for this rare occurrence, and proposed diagnostic and therapeutic algorithm are described.

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The popularity of smart sensors and the Internet of Things (IoT) is growing in various fields and applications. Both collect and transfer data to networks. However, due to limited resources, deploying IoT in real-world applications can be challenging.

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The development of non-invasive optoelectronic technologies for human blood monitoring is one of the important research areas for medicine. A critical analysis of optoelectronic methods of blood research and the micromechanical systems based on them is carried out in this article. A design realization of a polarizing portable system for non-invasive monitoring of hematocrit as one of the basic homeostatic constants of the human body containing information about the microphysical parameters of blood cells has been substantiated.

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Background: Eight human catalytic phosphoinositide 3-kinase (PI3K) isoforms exist which are subdivided into three classes. While class I isoforms have been well-studied in cancer, little is known about the functions of class II PI3Ks.

Materials And Methods: The expression pattern and functions of the class II PI3KC2β isoform were investigated in a panel of tumour samples and cell lines.

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Meckel's diverticulum is a congenital anomaly leading to the formation of a true diverticulum in the distal small intestine. Though most are asymptomatic and discovered incidentally, Meckel's diverticuli can give rise to a wide range of symptoms. Rarely, this can be a malignancy, most commonly a carcinoid tumor.

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During COVID-19, certain means were proposed to improve crowd management in the Birmingham New Street railway station. To validate the current system of crowd management in the station, this paper examines the rail passenger flow in the concourse of the Birmingham New Street railway station and the passenger interactions and queueing phenomena associated with it, mainly at the ticket machines, offices and gates, prior to and during the implementation of COVID-19 measures. The passenger behaviour in the concourse of the station was simulated using the SIMUL8 event-based simulation modelling package.

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In this work, we introduce and use an innovative approach for adaptive piecewise linear interval approximation of sensor characteristics, which are differentiable functions. The aim is to obtain a discreet type of inverse sensor characteristic, with a predefined maximum approximation error, with minimization of the number of points defining the characteristic, which in turn is related to the possibilities for using microcontrollers with limited energy and memory resources. In this context, the results from the study indicate that to overcome the problems arising from the resource constraints of smart devices, appropriate "lightweight" algorithms are needed that allow efficient connectivity and intelligent management of the measurement processes.

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Cell lysis is a process in which the outer cell membrane is broken to release intracellular constituents in a way that important information about the DNA or RNA of an organism can be obtained. This article is a thorough review of reported methods for the achievement of effective cellular boundaries disintegration, together with their technological peculiarities and instrumental requirements. The different approaches are summarized in six categories: chemical, mechanical, electrical methods, thermal, laser, and other lysis methods.

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Background: The 1,8-Naphthalimides constitute an important class of biologically active, DNAbinding compounds. There are no available data on the synthesis of 1,8-naphthalimide derivatives with nonprotein amino acids and their biological activity. The aim of this paper was to determine the synthesis, structural characterization and cytotoxic activity of new 1-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)cycloalkane-1- carboxylic acids with 5-, 6-, 7-, 8- and 12-membered rings as well as 2-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)- yl)adamantane-2-carboxylic acid and 1-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)-1,2,3,4-tetrahydronaphthalene- 1-carboxylic acid.

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Cushing's syndrome (CS) is associated with serious comorbidities and an increased mortality rate that could be reduced only if strict biochemical control is achieved. The aim of this study was to show the 50-year experience of a single tertiary center in the management of CS patients - the different treatment modalities used over the years and the corresponding outcomes. It was a retrospective study of a large cohort of patients from the Bulgarian CS database: 613 patients (374 with ACTH-dependent and 239 with ACTH-independent CS).

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Optic nerve glioma (ONG) is associated in 10% of patients with neurofibromatosis (NF) type 1. To date no consensus has been reached regarding the therapeutic approach and prevention of visual impairment in these patients. Reports in the literature vary from a conservative approach (observation) to the use of single treatment modalities or multimodality protocols of surgical removal, radiotherapy, and/or chemotherapy.

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This work describes a method for synthesis, as well as in vitro antiproliferative and antibacterial investigation of 3-methyl-9'-fluorenespiro-5-hydantoin. The structure of the substituted fluorenylspirohydantoin derivative was verified by UV-Vis, FT-IR, Raman, (1)H-NMR and (13)C-NMR spectroscopy, and by using a combination of 2D NMR experiments, which included (1)H-(1)H COSY, HMQC and HMBC sequences. The geometry of the compound was optimized by the B3LYP density functional with 6-31G(d) basis set and the (1)H and (13)C NMR spectra were predicted with the HF/6-31G(d) calculations at the optimized geometry.

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Pituitary adenomas (PAs) show a broad clinicomorphological spectrum. The proliferation activity, evaluated by MIB-1 labelling index (LI), and p53 expression have been pointed as predictive markers for invasiveness and progression. The aim of this study was to evaluate the proliferation rate and p53 expression and to look for any relationships with the clinical behaviour and follow-up results in a series of Bulgarian patients with PAs.

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Synthesis and characterization of new Pt(II) complexes of cyclohexanespiro-5-(2-thiohydantoin) (L1) and cycloheptanespiro-5-(2-thiohydantoin) (L2) are discussed. The new complexes are studied by elemental analysis, IR, ATR FTIR spectroscopy. The free ligands are investigated by UV-Vis, FT-IR, (1)H NMR, (13)C NMR and Raman spectroscopy.

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The synthesis of two novel compounds, 1-amino-3',4'-dihydro-2H,2'H,5H-spiro[imidazolidine-4,1'-naphthalene]-2,5-dione and 1,3-bis(hydroxymethyl)-3',4'-dihydro-2H,2'H,5H-spiro[imidazolidine-4,1'-naphthalene]-2,5-dione, was reported. The structures of the compounds were verified by (1)H, (13)C NMR and IR spectroscopy and quantum-chemical calculations at DFT level.

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This paper presents a method for synthesis and cytotoxicity of new platinum(II) complexes of (9'-fluorene)-spiro-5-hydantoin (L1) and (9'-fluorene)-spiro-5-(2-thiohydantoin) (L2). The new obtained complexes were studied by elemental analysis: ultraviolet-visible, attenuated total reflection Fourier transform infrared (ATR-FTIR), and H- and C-NMR for Pt(II) compounds and additionally Raman spectroscopy for free ligands. Based on the experimental data, the most probable structure of the complexes is suggested.

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Two methods for spirothiohydantoin synthesis are presented. The title compounds were prepared with reaction of the corresponding 1-aminocycloalkanecarboxylic acids and thiourea. These compounds were also prepared by a hydrolysis of the relevant spirodithiohydantoins with barium hydroxide.

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The regulation of cell morphology is a dynamic process under the control of multiple protein complexes acting in a coordinated manner. Phosphoinositide 3-kinases (PI3K) and their lipid products are widely involved in cytoskeletal regulation by interacting with proteins regulating RhoGTPases. Class II PI3K isoforms have been implicated in the regulation of the actin cytoskeleton, although their exact role and mechanism of action remain to be established.

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Background: Eight human catalytic phosphoinositide 3-kinase (PI3K) isoforms exist which are subdivided into three classes. While class I isoforms have been well-studied in cancer, little is known about the functions of class II PI3Ks.

Materials And Methods: The expression pattern and functions of the class II PI3KC2β isoform were investigated in a panel of tumour samples and cell lines.

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Complete assignments of the 1H and 13C NMR chemical shifts for 3-phenylmethylene-1H,3H-naphtho-[1,8-c,d]-pyran-1-one were done by means of one- and two-dimensional NMR techniques, including 1H-(1)H COSY, HMQC and HMBC spectra. Ab initio quantum chemistry calculations and a shift prediction by an incremental method provided values close to the proposed assignments. All mid-IR spectral bands are given as reference data.

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Purpose: The Akt/mammalian target of rapamycin (mTOR) pathway is frequently activated in human cancers and plays an important role in small cell lung cancer (SCLC) biology. We investigated the potential of targeting mTOR signaling as a novel antitumor approach in SCLC.

Experimental Design: The expression of mTOR in patient specimens and in a panel of SCLC cell lines was analyzed.

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Aim: The aim of this study was to determine the effect of the applied method of image investigation (CT or MRI) on the following parameters of the neuronavigation (NN) assisted procedure: "number of attempts for registration", "duration of registration" and "registration accuracy".

Patients And Methods: A total of 195 patients with various cranial pathological lesions underwent neuronavigation-assisted surgery between March 2003 and December 2005 at the Clinic of Neurosurgery of St. I.

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The presence of two or more hepatic ducts for biliary anastomosis in adult-to-adult right liver transplantation is not uncommon. In the case described here, the graft had two hepatic ducts: one corresponded anatomically to a normal right hepatic duct and the other ran parallel to the proper hepatic duct and drained into its distal to the cystic duct. Because of the small diameter of both duct orifices and the favorable length of the ducts, a cloaca type reconstruction was performed.

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Aim: The aim of this study was to investigate the effect of neuronavigation on the following parameters: "skin incision", "craniotomy", "intraoperative anatomical orientation", "dissection guiding", "localization of the pathological formation", "assessment of the degree of resection" and "duration of surgical procedure" in resections of intracranial cavernomas and to specify the indications for neuronavigation in their surgical treatment.

Patients And Methods: The present prospective study included 20 patients with intracranial cavernomas who underwent neuronavigated surgery between March 2003 and December 2005 at the Clinic of Neurosurgery of the "St. I.

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Neuronavigation is a result of the introduction and integration of high technologies into modern neurosurgery. The method is becoming increasingly available, and more than ever, its "fashionable", ungrounded application (literally, in each neurosurgical procedure) requires objective evaluation of its real usefulness. The aim of the present survey was to analyze the use of neuronavigation in the general fields of modern cranial neurosurgery.

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