Ramanovu spektroskopii lze v chemii použít nejen k určování chemického složení, ale také pro získávání dalších informací o struktuře materiálu. Ve spektrech semikrystalických polymerů lze nalézt vzájemně odlišné pásy charakteristické pro krystalickou nebo amorfní fázi, stanovit z nich krystalinitu a z ní odhadnout míru degradace polymeru. V předložené studii byly vyhodnoceny změny raménka pásu na vlnočtu 1733 cm−1 v Ramanových spektrech vlákna z poly(p-dioxanonu) podrobeného hydrolytické degradaci. Pro různě dlouhé doby degradace byly vypočteny obsahy ploch pod raménkem tohoto pásu a též byl proveden jeho modelový rozklad na předpokládané píky krystalické a amorfní fáze. Obsahy ploch pod raménkem i parametry modelových píků byly porovnány s hodnotami krystalinity získanými pomocí diferenční skenovací kalorimetrie, přičemž bylo dosaženo dobré shody. Tato práce ukazuje příklad využití Ramanovy spektroskopie při studiu hydrolytické degradace polymerů.
Raman spectroscopy can be used in chemistry not just to determine chemical composition, but also to obtain further information on the material structure. In the spectra of semi-crystalline polymers, distinct bands characteristic of the crystalline or the amorphous phase can be found, the degree of crystallinity determined from them, and the degree of polymer degradation estimated from the crystallinity. In the present study, changes in the 1733 cm−1 band shoulder in Raman spectra of poly(p-dioxanone) fibres subjected to hydrolytic degradation were evaluated. For different degradation periods, the areas under the shoulder of this band were calculated and a model deconvolution of this band into assumed crystalline and amorphous peaks was also performed. The areas under the shoulder, as well as the model peaks' parameters, were compared with the crystallinity values obtained by differential scanning calorimetry, achieving a good agreement. This work shows an example of using Raman spectroscopy when studying the hydrolytic degradation of polymers.
Time-resolved X-ray crystallography experiments were first performed in the 1980s, yet they remained a niche technique for decades. With the recent advent of X-ray free electron laser (XFEL) sources and serial crystallographic techniques, time-resolved crystallography has received renewed interest and has become more accessible to a wider user base. Despite this, time-resolved structures represent < 1 % of models deposited in the world-wide Protein Data Bank, indicating that the tools and techniques currently available require further development before such experiments can become truly routine. In this chapter, we demonstrate how applying data multiplexing to time-resolved crystallography can enhance the achievable time resolution at moderately intense monochromatic X-ray sources, ranging from synchrotrons to bench-top sources. We discuss the principles of multiplexing, where this technique may be advantageous, potential pitfalls, and experimental design considerations.
The leishmaniases are globally important parasitic diseases for which no human vaccines are currently available. To facilitate vaccine development, we conducted an open-label observational study to establish a controlled human infection model (CHIM) of sand fly-transmitted cutaneous leishmaniasis (CL) caused by Leishmania major. Between 24 January and 12 August 2022, we exposed 14 participants to L. major-infected Phlebotomus duboscqi. The primary objective was to demonstrate effectiveness of lesion development (take rate) and safety (absence of CL lesion at 12 months). Secondary and exploratory objectives included rate of lesion development, parasite load and analysis of local immune responses by immunohistology and spatial transcriptomics. Lesion development was terminated by therapeutic biopsy (between days 14 and 42 after bite) in ten participants with clinically compatible lesions, one of which was not confirmed by parasite detection. We estimated an overall take rate for CL development of 64% (9/14). Two of ten participants had one and one of ten participants had two lesion recurrences 4-8 months after biopsy that were treated successfully with cryotherapy. No severe or serious adverse events were recorded, but as expected, scarring due to a combination of CL and the biopsy procedure was evident. All participants were lesion free at >12-month follow-up. We provide the first comprehensive map of immune cell distribution and cytokine/chemokine expression in human CL lesions, revealing discrete immune niches. This CHIM offers opportunities for vaccine candidate selection based on human efficacy data and for a greater understanding of immune-mediated pathology. ClinicalTrials.gov identifier: NCT04512742 .
- MeSH
- Adult MeSH
- Leishmania major * immunology MeSH
- Leishmaniasis, Cutaneous * immunology parasitology pathology MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Parasite Load MeSH
- Phlebotomus parasitology immunology MeSH
- Animals MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Observational Study MeSH
Hypoxia represents one of the key factors that stimulates the growth of leukemic cells in their niche. Leukemic cells in hypoxic conditions are forced to reprogram their original transcriptome, miRNome, and metabolome. How the coupling of microRNAs (miRNAs)/mRNAs helps to maintain or progress the leukemic status is still not fully described. MiRNAs regulate practically all biological processes within cells and play a crucial role in the development/progression of leukemia. In the present study, we aimed to uncover the impact of hsa-miR-155-5p (miR-155, MIR155HG) on the metabolism, proliferation, and mRNA/miRNA network of human chronic lymphocytic leukemia cells (CLL) in hypoxic conditions. As a model of CLL, we used the human MEC-1 cell line where we deleted mature miR-155 with CRISPR/Cas9. We determined that miR-155 deficiency in leukemic MEC-1 cells results in lower proliferation even in hypoxic conditions in comparison to MEC-1 control cells. Additionally, in MEC-1 miR-155 deficient cells we observed decreased number of populations of cells in S phase. The miR-155 deficiency under hypoxic conditions was accompanied by an increased apoptosis. We detected a stimulatory effect of miR-155 deficiency and hypoxia at the level of gene expression, seen in significant overexpression of EGLN1, GLUT1, GLUT3 in MEC-1 miR-155 deficient cells. MiR-155 deficiency and hypoxia resulted in increase of glucose and lactate uptake. Pyruvate, ETC and ATP were reduced. To conclude, miR-155 deficiency and hypoxia affects glucose and lactate metabolism by stimulating the expression of glucose transporters as GLUT1, GLUT3, and EGLN1 [Hypoxia-inducible factor prolyl hydroxylase 2 (HIF-PH2)] genes in the MEC-1 cells.
- Publication type
- Journal Article MeSH
Current diabetic retinopathy (DR) treatment involves blood glucose regulation combined with laser photocoagulation or intravitreal injection of vascular endothelial growth factor (VEGF) antibodies. However, due to the complex pathogenesis and cross-interference of multiple biochemical pathways, these interventions cannot block disease progression. Recognizing the critical role of the retinal microenvironment (RME) in DR, it is hypothesized that reshaping the RME by simultaneously inhibiting primary and secondary blood-retinal barrier (BRB) injury can attenuate DR. For this, a glucose-responsive hydrogel named Cu-PEI/siMyD88@GEMA-Con A (CSGC) is developed that effectively delivers Cu-PEI/siMyD88 nanoparticles (NPs) to the retinal pigment epithelium (RPE). The Cu-PEI NPs act as antioxidant enzymes, scavenging ROS and inhibiting RPE pyroptosis, ultimately blocking primary BRB injury by reducing microglial activation and Th1 differentiation. Simultaneously, MyD88 expression silence in combination with the Cu-PEI NPs decreases IL-18 production, synergistically reduces VEGF levels, and enhances tight junction proteins expression, thus blocking secondary BRB injury. In summary, via remodeling the RME, the CSGC hydrogel has the potential to disrupt the detrimental cycle of cross-interference between primary and secondary BRB injury, providing a promising therapeutic strategy for DR.
- MeSH
- Cellular Microenvironment drug effects MeSH
- Diabetic Retinopathy * drug therapy metabolism MeSH
- Glucose * metabolism MeSH
- Blood-Retinal Barrier * metabolism drug effects MeSH
- Hydrogels * pharmacology MeSH
- Disease Models, Animal MeSH
- Mice MeSH
- Nanoparticles MeSH
- Retina drug effects metabolism MeSH
- Retinal Pigment Epithelium metabolism drug effects MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Several in vitro models have been developed to mimic chronic lymphocytic leukemia (CLL) proliferation in immune niches; however, they typically do not induce robust proliferation. We prepared a novel model based on mimicking T-cell signals in vitro and in patient-derived xenografts (PDXs). Six supportive cell lines were prepared by engineering HS5 stromal cells with stable expression of human CD40L, IL4, IL21, and their combinations. Co-culture with HS5 expressing CD40L and IL4 in combination led to mild CLL cell proliferation (median 7% at day 7), while the HS5 expressing CD40L, IL4, and IL21 led to unprecedented proliferation rate (median 44%). The co-cultures mimicked the gene expression fingerprint of lymph node CLL cells (MYC, NFκB, and E2F signatures) and revealed novel vulnerabilities in CLL-T-cell-induced proliferation. Drug testing in co-cultures revealed for the first time that pan-RAF inhibitors fully block CLL proliferation. The co-culture model can be downscaled to five microliter volume for large drug screening purposes or upscaled to CLL PDXs by HS5-CD40L-IL4 ± IL21 co-transplantation. Co-transplanting NSG mice with purified CLL cells and HS5-CD40L-IL4 or HS5-CD40L-IL4-IL21 cells on collagen-based scaffold led to 47% or 82% engraftment efficacy, respectively, with ~20% of PDXs being clonally related to CLL, potentially overcoming the need to co-transplant autologous T-cells in PDXs.
- MeSH
- Stromal Cells * metabolism pathology MeSH
- Leukemia, Lymphocytic, Chronic, B-Cell * pathology genetics drug therapy MeSH
- Protein Kinase Inhibitors pharmacology MeSH
- Interleukins genetics metabolism MeSH
- Coculture Techniques * MeSH
- Humans MeSH
- CD40 Ligand * metabolism genetics MeSH
- Mice MeSH
- Cell Proliferation * MeSH
- T-Lymphocytes immunology metabolism MeSH
- Xenograft Model Antitumor Assays MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Crocosphaera watsonii is a unicellular N2-fixing (diazotrophic) cyanobacterium observed in tropical and subtropical oligotrophic oceans. As a diazotroph, it can be a source of bioavailable nitrogen (N) to the microbial community in N-limited environments, and this may fuel primary production in the regions where it occurs. Crocosphaera watsonii has been the subject of intense study, both in culture and in field populations. Here, we summarize the current understanding of the phylogenetic and physiological diversity of C. watsonii, its distribution, and its ecological niche. Analysis of the relationships among the individual Crocosphaera species and related free-living and symbiotic lineages of diazotrophs based on the nifH gene have shown that the C. watsonii group holds a basal position and that its sequence is more similar to Rippkaea and Zehria than to other Crocosphaera species. This finding warrants further scrutiny to determine if the placement is related to a horizontal gene transfer event. Here, the nifH UCYN-B gene copy number from a recent synthesis effort was used as a proxy for relative C. watsonii abundance to examine patterns of C. watsonii distribution as a function of environmental factors, like iron and phosphorus concentration, and complimented with a synthesis of C. watsonii physiology. Furthermore, we have summarized the current knowledge of C. watsonii with regards to N2 fixation, photosynthesis, and quantitative modeling of physiology. Because N availability can limit primary production, C. watsonii is widely recognized for its importance to carbon and N cycling in ocean ecosystems, and we conclude this review by highlighting important topics for further research on this important species.
- MeSH
- Nitrogen Fixation * MeSH
- Phylogeny * MeSH
- Cyanobacteria * genetics metabolism physiology MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Dyslexie je zřejmě nejznámější specifickou poruchou učení. Veřejností bývá často zjednodušeně chápána jako porucha schopnosti (na)učit se číst, avšak jedná se o mnohem komplexnější problém. Obvykle mívá zřetelně negativní dopad na školní prospěch žáků, přestože mnozí žáci s dyslexií mohou mít výbornou prostorovou představivost a výbornou schopnost řešit problémy komplexního charakteru. O dyslexii bylo napsáno mnoho publikací. Většina z nich se zabývá medicínskými nebo psychologickými aspekty dyslexie nebo se snaží žákům s dyslexií napomoci při čtení nebo jeho nácviku. Podstatně menší počet vědeckých prací se soustředí na pomoc s výukou konkrétních vyučovacích předmětů. Mezi nimi převládá snaha pomoci žákům se studiem cizích jazyků. Jen extrémně malý počet studií je zaměřen na dyslexii a přírodovědné předměty (např. chemii). Cílem naší práce bylo vytvořit přehled informací o dyslexii a výuce chemie na základě textů publikovaných ve světové vědecké literatuře. Naše hypotéza, založená na studiu vědecké literatury o dyslexii a na našich zkušenostech s velmi limitovaným počtem spolupracujících žáků / studentů s dyslexií, případně s jejich učiteli, je následující: dyslexie se obvykle poprvé projeví během úvodního nácviku čtení. Čtení však může být postupně natrénováno až na společensky akceptovatelnou rychlost. To některé učitele může vést k mylnému názoru, že čtrnáctiletí žáci dyslexii již „zvládli“ a že tedy v přírodovědných předmětech mohou pracovat stejným způsobem jako ostatní žáci. Některé články však poukazují na skutečnost, že žáci s dyslexií se od běžné populace mohou lišit způsobem práce s pamětí. Na pamětní zvládnutí učiva mohou potřebovat mnohem delší čas. Například „pouhé“ zapamatování si značek a názvů chemických prvků pro ně může být extrémně obtížný a časově náročný úkol. Žáci s dyslexií mohou velmi ocenit vizualizace (pokusy, obrázky, ukázky skutečných chemických látek, modely, videa). Důvodem nemusí být jen samotný problém se čtením, ale i způsob myšlení (potřeba „překladu“ ze slov do reality). Mohou mít užitek z jasného strukturovaného vysvětlování a jasných výstupních požadavků. Na druhou stranu, mnozí z nich jsou kreativní a mají dobrou (až nadprůměrnou) schopnost řešit komplexní problémy. Výukové techniky, které pomáhají žákům s dyslexií, pomáhají všem žákům.
Dyslexia is probably the best-known specific learning difficulty. For many people it is simply known as a reading disorder, even though it is a much more complex problem. It usually has a noticeable negative impact on pupils' school performance, although many dyslexics can have excellent space imagination and ability to solve complex problems. Many publications have been written about dyslexia. The most of them deal with its medical and psychological aspects or they are trying to help dyslexics to read. A significantly smaller number of scientific papers is focused on help with specific school subjects. Among them, the predominant effort is to help the pupils with foreign languages study. Only extremely small number of studies is focused on dyslexia and science subjects (for instance chemistry). The aim of our article was to create an overview of information published in scientific literature, focused on dyslexia and teaching chemistry. Our hypothesis, based on our study of scientific articles on dyslexia and on our experience with a very limited number of cooperating pupils/students with dyslexia, or with their teachers, is as follows: dyslexia is usually found during the initial reading practice. However, reading can usually be gradually practiced to an acceptable level. That is why some teachers think incorrectly that 14 years old pupils have already "overcome dyslexia" and that they can work within science subjects in the same way as the other pupils. However, dyslexics might differ from the population in the way how they work with their memory. They might need much longer time to memorize. For example, a "simple" memorizing the symbols and names of chemical elements can be an extremely difficult and time-consuming task for them. The dyslexics might greatly appreciate visualizations (experiments, pictures, showing real chemical substances, models, videos). The reason might be not the reading problem itself, but the way of thinking (the need of a "translation" from words into reality). They might profit from a clearly structured explanation including clear output requirements. On the other hand, many of them are creative and have a good (even above average) ability to solve complex problems. Techniques that help dyslexics help all pupils/students.
Crimean-Congo haemorrhagic fever (CCHF) is the most widely distributed tick-borne viral disease in humans and is caused by the Crimean-Congo haemorrhagic fever virus (CCHFV). The virus has a broader distribution, expanding from western China and South Asia to the Middle East, southeast Europe, and Africa. The historical known distribution of the CCHFV vector Hyalomma marginatum in Europe includes most of the Mediterranean and the Balkan countries, Ukraine, and southern Russia. Further expansion of its potential distribution may have occurred in and out of the Mediterranean region. This study updated the distributional map of the principal vector of CCHFV, H. marginatum, in the Old World using an ecological niche modeling approach based on occurrence records from the Global Biodiversity Information Facility (GBIF) and a set of covariates. The model predicted higher suitability of H. marginatum occurrences in diverse regions of Africa and Asia. Furthermore, the model estimated the environmental suitability of H. marginatum across Europe. On a continental scale, the model anticipated a widespread potential distribution encompassing the southern, western, central, and eastern parts of Europe, reaching as far north as the southern regions of Scandinavian countries. The distribution of H. marginatum also covered countries across Central Europe where the species is not autochthonous. All models were statistically robust and performed better than random expectations (p < 0.001). Based on the model results, climatic conditions could hamper the successful overwintering of H. marginatum and their survival as adults in many regions of the Old World. Regular updates of the models are still required to continually assess the areas at risk using up-to-date occurrence and climatic data in present-day and future conditions.
- MeSH
- Hemorrhagic Fever, Crimean * epidemiology MeSH
- Ixodidae * MeSH
- Humans MeSH
- Tick-Borne Diseases * MeSH
- Hemorrhagic Fever Virus, Crimean-Congo * MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Europe MeSH
Tento článek kriticky posuzuje platnost tradičních modelů comingoutu v kontextu současného Česka, neboť integruje zažité přístupy a moderní realitu. Ke zkoumání vývoje tří milníků comingoutu (M1 - přitažlivost, M2 - sebeoznačení a M3 - odhalení) ve vývoji neheterosexuální identity byl využit online průzkum, kterého se zúčastnilo 1 778 osob (ve věku 15 až 71 let). Z výsledků vyplývá, že svou touhu neheterosexuální lidé rozpoznají kolem 13, roku života, průměrně přes dva další roky trvá, než tuto svou identitu poprvé pojmenují, a průměrně ještě téměř dva další roky trvá, než se daná osoba rozhodne svěřit někomu dalšímu. První "vnější coming out" tak probíhá průměrně ve věku necelých 17 let. V rámci studie jsme potvrdili generační i genderové rozdíly, přičemž mladší generace procházejí těmito vývojovými milníky rychleji a tradiční genderové rozdíly se u nich stírají. Článek také naznačuje budoucí směr výzkumu, včetně zkoumání nástupu přitažlivosti u bisexuálních a pansexuálních osob osob a vzorců přitažlivosti vůči trans a genderově rozmanitým osobám, a také posouzení toho, jak stigma a předsudky ovlivňují vývoj neheterosexuální identity.
This paper critically examines the applicability of traditional coming-out models in the context of contemporary Czechia, integrating rooted approaches and modern realities. An online survey of 1,788 participants (aged 15 to 71) was utilized to investigate progression between three coming-out milestones (M1 - Attraction; M2 - Self-Labeling; and M3 - Disclosure) in the development of non-heterosexual identity. Results reveal that non-heterosexual individuals typically recognize their desire around age 13, self-label, on average, just over two years later, and disclose their identity to another person at an average age of just under 17. Notably, the study highlights generational and gender differences in these milestones, with younger generations progressing faster and traditional gender distinctions becoming less distinct. The paper also identifies future research directions, including exploring the onset of attractions in bisexual and pansexual individuals and attraction patterns toward trans and gender-diverse individuals, and assessing how stigma and prejudice shape non-heterosexual identity development.
- MeSH
- Adult MeSH
- Gender Identity * MeSH
- Middle Aged MeSH
- Humans MeSH
- Adolescent MeSH
- Surveys and Questionnaires MeSH
- Aged MeSH
- Sexual and Gender Minorities MeSH
- Sexual Behavior MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Adolescent MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
- Geographicals
- Czech Republic MeSH
