Selection of processing parameters for conversion coatings on high-strength aluminium alloys by cyclic voltammetry

A method of recording copper enrichment on AA2000 series alloys by means of cyclic voltammetry in borate buffer preceded by immersion of the samples in 0.6 M NaCl solution is extended to the assessment of various surface treatments like alkaline cleaning, desmutting, phosphating and also inorganic and organic corrosion inhibitors. Since the height of the peak determined from voltammograms results from Cu/Cu+ charge transfer taking place on Al–Cu surface a selection of adequate substances or technological parameters inhibiting this reaction may find an application in elaboration or modifying of surface technology. In this work the particular technological steps of the complex electrophosphating process of AA2017 were elaborated using results obtained from voltammetric transients. It was shown that a partial removal of Cu from the surface without affecting bulk content was the most effective de-smutting stage while inhibitors of Al/Cu corrosion were effective in the post-treatment stage.Розширено застосування методу дослідження збагачення міддю сплавів серії АА2000 за допомогою циклічної вольтамперометрії у боратному буфері після попереднього витримування зразків у 0,6 M розчині NaCl для оцінки різних поверхневих обробок, зокрема лужного очищення, освітлення, фосфатування, а також неорганічних та органічних інгібіторів корозії. Оскільки висота піка, визначена з вольтамперограм, є результатом перенесення заряду Cu/Cu+ на поверхні Al–Cu, вибір відповідних речовин чи технологічних параметрів, що інгібують цю реакцію, може знайти застосування у розробці або модифікації технологій поверхневої обробки. Розроблено конкретні технологічні кроки для комплексного електрофосфатування сплаву АА2017 з використанням результатів вивчення вольтамперометричних перехідних процесів. Показано, що часткове усунення Cu з поверхні, без впливу на її об’ємний вміст у сплаві, найефективніше на стадії освітлення, тоді як інгібітори корозії сплаву Al/Cu найкраще діють на стадії фінальної обробки.Расширено применение метода исследования обогащения медью сплавов серии АА2000 с помощью циклической вольтамперометрии в боратном буфере после предварительной выдержки образцов в 0,6 M растворе NaCl для оценки разных поверхностных обработок, в частности щелочной очистки, освещения, фосфатирования, а также неорганических и органических ингибиторов коррозии. Поскольку высота пика, определенная из вольтамперограмм, является результатом перенесения заряда Cu/Cu+ на поверхности Al–Cu, выбор соответствующих веществ или технологических параметров, ингибирующих эту реакцию, может найти применение в разработке или модификации технологий поверхностной обработки. Разработаны конкретные технологические шаги для комплексного электрофосфатирования сплава АА2017 с использованием результатов изучения вольтамперометрических переходных процессов. Показано, что частичное устранение Cu из поверхности, без влияния на ее объемное содержание в сплаве, наиболее эффективно на стадии освещения, тогда как ингибиторы коррозии сплава Al/Cu лучше всего действуют на стадии финальной обработки

Telomerase activity and telomere length in primary and metastatic tumors from pediatric bone cancer patients

The presence of telomerase activity has been analyzed in almost all tumor types and tumor-derived cell lines. However, there are very few studies that focus on the presence of telomerase activity in bone tumors, and most of them report analysis on very few samples or bone-derived cell lines. The objective of this study was to analyze the telomere length and telomerase activity in primary tumors and metastatic lesions from pediatric osteosarcoma and Ewing's sarcoma patients. The presence of telomerase activity was analyzed by the telomeric repeat amplification protocol assay, and the telomere length was measured by Southern blot. Results were related to survival and clinical outcome. Telomerase activity was detected in 85% of the bone tumor metastases (100% Ewing's sarcomas and 75% osteosarcomas) but only in 12% of the primary tumors (11.1% osteosarcomas and 12.5% Ewing's sarcomas). Bone tumor tissues with telomerase activity had mean telomere lengths 3 kb shorter than those with no detectable telomerase activity (p = 0.041). The presence of telomerase activity was associated with survival (p = 0.009), and longer event-free survival periods were found in patients who lacked telomerase activity compared with those who had detectable telomerase activity levels in their tumor tissues (p = 0.037). The presence of longer telomeres in primary pediatric bone tumors than in metastases could be indicative of alternative mechanisms of lengthening of telomeres for their telomere maintenance rather than telomerase activity. Nevertheless, the activation of telomerase seems to be a crucial step in the malignant progression and acquisition of invasive capability of bone tumors

Aging, telomeres and heart failure

During normal aging, the heart undergoes functional, morphological and cellular changes. Although aging per se does not lead to the expression of heart failure, it is likely that age-associated changes lower the threshold for the manifestation of signs and symptoms of heart failure. In patients, the susceptibility, age of onset and pace of progression of heart failure are highly variable. The presence of conventional risk factors cannot completely explain this variability. Accumulation of DNA damage and telomere attrition results in an increase in cellular senescence and apoptosis, resulting in a decrease in the number and function of cells, contributing to the overall tissue and organ dysfunction. Biological aging, characterized by reduced telomere length, provides an explanation for the highly interindividual variable threshold to express the clinical syndrome of heart failure at some stage during life. In this review, we will elaborate on the current knowledge of aging of the heart, telomere biology and its potential role in the development of heart failure

Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke).

BACKGROUND: Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation. METHODS: STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0-2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass. RESULTS: A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients ( CONCLUSIONS: In this large, real-world study, interhospital transfer was associated with significant treatment delays and lower chance of good outcome. Strategies to facilitate more rapid identification of large-vessel occlusion and direct routing to endovascular-capable centers for patients with severe stroke may improve outcomes. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239640

Role of Matrix Metalloproteinases and Therapeutic Benefits of Their Inhibition in Spinal Cord Injury

This review will focus on matrix metalloproteinases (MMPs) and their inhibitors in the context of spinal cord injury (SCI). MMPs have a specific cellular and temporal pattern of expression in the injured spinal cord. Here we consider their diverse functions in the acutely injured cord and during wound healing. Excessive activity of MMPs, and in particular gelatinase B (MMP-9), in the acutely injured cord contributes to disruption of the blood-spinal cord barrier, and the influx of leukocytes into the injured cord, as well as apoptosis. MMP-9 and MMP-2 regulate inflammation and neuropathic pain after peripheral nerve injury and may contribute to SCI-induced pain. Early pharmacologic inhibition of MMPs or the gelatinases (MMP-2 and MMP-9) results in an improvement in long-term neurological recovery and is associated with reduced glial scarring and neuropathic pain. During wound healing, gelatinase A (MMP-2) plays a critical role in limiting the formation of an inhibitory glial scar, and mice that are genetically deficient in this protease showed impaired recovery. Together, these findings illustrate complex, temporally distinct roles of MMPs in SCIs. As early gelatinase activity is detrimental, there is an emerging interest in developing gelatinase-targeted therapeutics that would be specifically tailored to the acute injured spinal cord. Thus, we focus this review on the development of selective gelatinase inhibitors

Tannic Acid Modified Silver Nanoparticles Show Antiviral Activity in Herpes Simplex Virus Type 2 Infection

The interaction between silver nanoparticles and herpesviruses is attracting great interest due to their antiviral activity and possibility to use as microbicides for oral and anogenital herpes. In this work, we demonstrate that tannic acid modified silver nanoparticles sized 13 nm, 33 nm and 46 nm are capable of reducing HSV-2 infectivity both in vitro and in vivo. The antiviral activity of tannic acid modified silver nanoparticles was size-related, required direct interaction and blocked virus attachment, penetration and further spread. All tested tannic acid modified silver nanoparticles reduced both infection and inflammatory reaction in the mouse model of HSV-2 infection when used at infection or for a post-infection treatment. Smaller-sized nanoparticles induced production of cytokines and chemokines important for anti-viral response. The corresponding control buffers with tannic acid showed inferior antiviral effects in vitro and were ineffective in blocking in vivo infection. Our results show that tannic acid modified silver nanoparticles are good candidates for microbicides used in treatment of herpesvirus infections.This work was supported by the Polish National Science Centre grant No. 2011/03/B/NZ6/04878 (for MK) and Centre for Preclinical Research and Technology (CePT) Project No. POIG.02.02.00-14-024/08-0 (for MG and MD). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscrip

Simulation tests of match-making method of complex services in the field of Web GIS

W pracy przedstawione zostały badania dotyczące wykorzystania systemu ekspertowego do zestawiania internetowych usług złożonych w dziedzinie Geograficznych Systemów Informacyjnych. W celu przeprowadzenia eksperymentu przygotowany został system komputerowy realizujący zaproponowaną przez autora metodę. Praca ta opisuje architekturę zaprojektowanego systemu, elementy składowe metody takie jak: baza wiedzy, ontologia dziedzinowa, semantyczny opis usługi, język specyficzny dla domeny oraz system produkcyjny, pełniący rolę doradcy inżyniera domeny. W drugiej części artykułu zaprezentowane zostały wyniki badań wskazujące na przydatność metody oraz skuteczność wykorzystania systemu ekspertowego w rozwiązywaniu przedstawionych zagadnień. Oceny dokonano przeprowadzając zestaw symulacji określających poprawność wydawanych ekspertyz oraz czas odpowiedzi systemu opartego o obiektowo zorientowany silnik reguł.Results of research related to application of expert system in intelligent discovery and matchmaking of complex Web services within Geographic Information Systems domain are presented in the paper. To perform the experiment, the computer system has been prepared by the author to fulfill proposed method. The first part of the paper describes the architecture of designed system and its components: knowledge base, domain ontology, semantic description of services, domain-specific language and production expert system, acting as the domain engineer's advisor. In the second part of this article, research results were presented to indicate how useful the method was and the effectiveness of the expert system use in solving the raised issues. The evaluation has been carrying out by a set of simulations which determine the correctness of published expertise and the response time of a system based on object-oriented rules engine. The paper shows results of conducted simulations and the conclusions drawn from those results. Based on the opinions issued by the developed integrated expert system, it can be stated that it has acceptable correctness. Queries expressed in the DSL were of great diversity, in the context of established to obtain expertise. Despite the high level of flexibility to formulate these queries, conclusions presented by the system were consistent with the stated objective. Nowadays, the main criterion posed by Internet users is information time access. Studies have shown that in less than 10 seconds an answer of expert system, with an integrated knowledge base consisting of about one thousand to two thousand facts can be obtained