Size exclusion chromatography for analyses of fibroin in silk : optimization of sampling and separation conditions

A direct goal of this paper was to improve the methods of sample preparation and separation for analyses of fibroin polypeptide with the use of size exclusion chromatography (SEC). The motivation for the study arises from our interest in natural polymers included in historic textile and paper artifacts, and is a logical response to the urgent need for developing rationale-based methods for materials conservation. The first step is to develop a reli- able analytical tool which would give insight into fibroin structure and its changes caused by both natural and arti- ficial ageing. To investigate the influence of preparation conditions, two sets of artificially aged samples were pre- pared (with and without NaCl in sample solution) and measured by the means of SEC with multi angle laser light scattering detector. It was shown that dialysis of fibroin dissolved in LiBr solution allows removal of the salt which destroys stacks chromatographic columns and prevents reproducible analyses. Salt rich (NaCl) water solutions of fibroin improved the quality of chromatograms

Decline. Mennonite cemeteries in cultural space of Vistula River Delta

Cmentarze mennonickie są jednym z elementów wielonarodowej mozaiki kulturowej, jaką można odnaleźć na Żuławach Wiślanych. Obecne są w krajobrazie od ponad dwustu pięćdziesięciu lat. Dramatyczne wydarzenia II wojny światowej i powojenne akcje wysiedleńcze spowodowały, że miejsca te straciły swoich prawowitych opiekunów. Opuszczone i zaniedbane dzielą losy wielu zamkniętych zabytkowych nekropolii protestanckich czy żydowskich synagog w Polsce. Celem opracowania jest przedstawienie współczesnej, nieoczywistej (jak by się mogło wydawać), historii mennonickich cmentarzy i obiektów sakralnych. Oparte zostało ono na badaniach terenowych nekropolii i lapidariów Delty Wisły w Cyganku-Żelichowie, Fiszewie, Jezierniku, Niedźwiedziówce, Pordenowie, Stalewie, Stawcu i Szaleńcu.The Mennonite cemeteries are a part of a multinational cultural mosaic that can be found on the Vistula River Delta. They are present in the landscape for more than two hundred years. The dramatic events of World War II and postwar displacement actions caused that this places have lost their respective guardians. Abandoned and neglected share the fate of many closed-old necropolis of Protestant or Jewish synagogues in Poland. The purpose of this paper is to present contemporary, non-obvious (as it might seems) history of Mennonite cemeteries and places of worship. It was based on. eld studies of the cemetery on Vistula Delta area: Cyganek-Żelichowo, Fiszewo, Jeziernik, Niedźwiedziówka, Pordenowo, Stalewo Stawiec and Szaleniec

Content of macro- and microelements in goat milk in relation to the lactation stage and region of production

The content of macro- and microelements in milk depends on a variety of environmental, genetic and physiological factors. The aim of the study was to determine the effect of the region of production and stage of lactation, associated with the production season, on the content of selected macro- and microelements, including potentially toxic elements, in goat milk. The material consisted of goat milk samples collected from farms in two regions of Poland: 74 samples from central-eastern Poland (the Provinces of Lublin and Świętokrzyskie) and 149 from southern Poland (the Bieszczady mountains). The milk was collected in three seasons: winter (75 samples), summer (111) and autumn-winter (37). In each milk sample, the percentage of casein, protein, fat, lactose and dry matter was determined, as well as the concentrations of K, Ca, Na, Mg, Zn, Fe, Cu and Mn. K, Ca, Na, Mg and Zn using a Varian 240FS AA spectrometer, by the flame atomic absorption technique, while Fe, Cu and Mn were determined in a graphite furnace with the Zeeman background correction, using a Varian 240Z AA spectrometer. The goats’ production peak was in the summer, when they were at pasture. From mid-lactation they produced milk with significantly (p ≤ 0.01) higher concentration of components. Milk obtained in stage I of lactation (winter feeding) was the richest source of Zn, Fe and Cu, while stage II milk (summer feeding) had the highest K content, and stage III milk (autumn-winter feeding) had the highest content of Ca, Na, Mg and Mn. Concentration of Zn, Fe and Cu decreased over the course of lactation. Milk obtained in the Bieszczady mountain region had significantly (p ≤ 0.01) higher content of dry matter, fat and protein. It also contained significantly (p ≤ 0.01) more Ca, Na, and Mg, and less K and Zn in comparison with the milk of the goats raised in central-eastern Poland. The highest positive correlation coefficients were noted between the content of Ca and Mg, Zn and Fe, Zn and Cu, Na and Mg, and Fe and Cu, while K content was negatively correlated with that of Na, Ca and Mg (p ≤ 0,001)

How to estimate cellulose condition in insulation transformers papers? : combined chromatographic and spectroscopic study

This study focuses on the temporal stability of insulation paper used in power transformers and intends to provide reliable and comprehensive estimators for the assessment of paper degradation state. To achieve the objectives artificially aged model papers were investigated along with power transformers insulation papers, by means of Size Exclusion Chromatography (SEC), Fourier-Transform Infrared Spectroscopy (FT-IR), ultraviolet–visible (UV–Vis) reflectance spectroscopy. The results of the UV–Vis analysis were compared to quantum chemical calculations performed by using time-dependent-Density Functional Theory method. The selection of methods allows the assessment of paper degradation state by characterization of depolymerisation progress and development of carbonyl groups. Our results not only are aimed to collect a data basis for paper condition assessment but also to increase the understanding of the mechanism of cellulose degradation in terms of relationship between aging conditions, different degradation paths and its observed effects

Immunosuppressive treatment during pregnancy as a potential factor changing magnesium, calcium and phosphorus levels in hard tissues of female rats and their offspring

Immunosuppressive therapy is necessary to prevent transplant rejection, also in the case of pregnant transplant recipients, which means that the medications may influence foetal development. An ideal immunosuppressive regimen should provide for excellent immunosuppression with minimal or no side effects. Yet, current immunosuppressive therapy regimens commonly used in clinical applications fail to meet this criterion. One of the complications caused by immunosuppressive drugs are mineralisation disorders in hard tissues. Therefore, in this study, we evaluated the impact of three regimens of immunosuppressive therapy used after renal transplantation, containing medications which are indicated (prednisone, cyclosporine A (CsA), tacrolimus (Tc)) and contraindicated (mycophenolate mofetil (MMF), everolimus) during pregnancy on the concentrations of essential minerals, calcium (Ca), phosphorus (P) and magnesium (Mg), affecting normal bone formation. The samples were analysed using inductively coupled plasma optical emission spectrometry (ICP-OES, ICAP 7400 Duo, Thermo Scientific) equipped with a concentric nebuliser and a cyclonic spray chamber. The immunosuppressive regimens under study had no effect on the levels of Mg and P, but they did contribute to increased bone Ca levels in the mothers in the group receiving Tc, MMF and prednisone and group receiving CsA, everolimus and prednisone. In the offspring of tested mother rats, immunosuppressive therapies may affect Mg levels in hard tissues. The immunosuppressive regimens administered at therapeutic doses are harmful to rat foetuses as evidenced by the small number or lack of offspring in the tested groups

Ex Situ and In Situ Artificial Thermo-Aging Study of the Natural Degradation of <i>Bombyx mori</i> Silk Fibroin

This study investigates the degradation mechanism of silk fibroin through Fourier-transformed infrared spectroscopy (FTIR) analysis. The secondary structure of silk fibroin-based materials is monitored using FTIR, and various estimators are calculated to assess the impact of degradation conditions and aging time. The oxidation estimator shows consistent growth, indicating peptide bond oxidation from the early stages of artificial aging, regardless of the conditions. The environment influences the hydrolysis estimator, with water introduction leading to significant changes. The crystallinity estimator reflects the overall degradation level, affected by oxidation and hydrolysis. XRD and FTIR analysis of historical silk banners up to 500 years old demonstrate a decrease in crystallinity and an increase in hydrolysis and oxidation. The presence of water accelerates the oxidation process, while crystallinity changes are primarily driven by oxidation. Fibroin degradation affects both antiparallel and parallel regions, with water playing a crucial role in accelerating hydrolysis and causing structural shifts. This study enhances our understanding of silk fibroin degradation and provides valuable insights for preserving historical silk artifacts

A novel risk model for predicting potentially life-threatening arrhythmias in non-ischemic dilated cardiomyopathy (DCM-SVA risk)

BACKGROUND: Non-ischemic dilated cardiomyopathy (DCM) can be complicated by sustained ventricular arrhythmias (SVA) and sudden cardiac death (SCD). By now, left-ventricular ejection fraction (LV-EF) is the main guideline criterion for primary prophylactic ICD implantation, potentially leading either to overtreatment or failed detection of patients at risk without severely impaired LV-EF. The aim of the European multi-center study DETECTIN-HF was to establish a clinical risk calculator for individualized risk stratification of DCM patients. METHODS: 1393 patients (68% male, mean age 50.7 ± 14.3y) from four European countries were included. The outcome was occurrence of first potentially life-threatening ventricular arrhythmia. The model was developed using Cox proportional hazards, and internally validated using cross validation. The model included seven independent and easily accessible clinical parameters sex, history of non-sustained ventricular tachycardia, history of syncope, family history of cardiomyopathy, QRS duration, LV-EF, and history of atrial fibrillation. The model was also expanded to account for presence of LGE as the eight8h parameter for cases with available cMRI and scar information. RESULTS: During a mean follow-up period of 57.0 months, 193 (13.8%) patients experienced an arrhythmic event. The calibration slope of the developed model was 00.97 (95% CI 0.90-1.03) and the C-index was 0.72 (95% CI 0.71-0.73). Compared to current guidelines, the model was able to protect the same number of patients (5-year risk ≥8.5%) with 15% fewer ICD implantations. CONCLUSIONS: This DCM-SVA risk model could improve decision making in primary prevention of SCD in non-ischemic DCM using easily accessible clinical information and will likely reduce overtreatment