Oxygen diffusion pathways in mutated forms of a LOV photoreceptor from Methylobacterium radiotolerans: a molecular dynamics study.

Mr4511 LOV (Light, Oxygen and Voltage) protein is a blue light sensing photoreceptor from Methylobacterium radiotolerans, binding flavin mononucleotide (FMN) as chromophore. Blue light activation of LOV domains triggers the reversible formation of a FMN-cysteine adduct by a photocycle that goes through the FMN excited triplet state. LOV domains can be engineered as fluorescent sensors and actuators for optogenetics and photomedicine [1]. First experimental data on Mr4511 LOV protein [2] indicate its high potential as a photosensitizer for singlet oxygen (SO) the cytotoxic reactive excited state of molecular oxygen, produced by diffusion limited energy transfer from the FMN triplet state. This feature is obtained after the single mutation of reactive cysteine C71, a change that prevents formation of the photoproduct. In addition, the lack of a tryptophan, conserved in ca. 75% of LOV domains and shown to strongly quench the FMN triplet lifetime (T) in LOV proteins, allows for Mr4511 LOV a longer T than for other LOV domains in C71S and C71G variants [2]. After an homology modeling of Mr4511 LOV, that has lead to a dimeric protein stabilized by the presence of a strong leucine zipper in the C-terminal helices, a mutation of the photocycle substrate cysteine into serine (C71S) has been introduced in silico to make it a SO photosensitizer, and the mutated form stability was tested by MD simulations. Afterwards, both transient and persistent oxygen channels were detected and analysed both in the wt and in the mutated protein. Molecular oxygen was then placed both outer and into the chromophore cavity and potential diffusion pathways were explored with MD simulations, showing a high accessibility of the binding cavity and a high persistence of oxygen inside. Mutations that might favor SO generation were designed based on their position with respect to the FMN and the oxygen channels, taking into account the ability of certain amino acids to quench FMN triplet state and SO. Therefore, C71S/Y61T and C71S/Y61S double mutants were generated in silico and their stability was checked. The analysis of their oxygen diffusion pathways showed an increased diffusion and persistence of oxygen molecules inside the binding cavity, indicating a promising model for SO photosensing and its biomedical and biophysical applications. [1] A. Losi, et al., Chem. Rev. 118 (2018): 10659-10709. [2] E. Consiglieri, et al., Photochem. Photobiol. Sci. 18 (2019): 2657–2660

Current trends in polymer based sensors

This review illustrates various types of polymer and nanocomposite polymeric based sensors used in a wide variety of devices. Moreover, it provides an overview of the trends and challenges in sensor research. As fundamental components of new devices, polymers play an important role in sensing applications. Indeed, polymers offer many advantages for sensor technologies: their manufacturing methods are pretty simple, they are relatively low-cost materials, and they can be functionalized and placed on different substrates. Polymers can participate in sensing mechanisms or act as supports for the sensing units. Another good quality of polymer-based materials is that their chemical structure can be modified to enhance their reactivity, biocompatibility, resistance to degradation, and flexibility

New Rheumatoid Arthritis Treatments for ‘Old’ Patients : Results of a Systematic Review

Introduction: In the last 20 years, biologic and targeted synthetic disease-modifying antirheumatic drugs (DMARDs) have become available for treating rheumatoid arthritis (RA), and a treat-to-target strategy has been introduced. We hypothesise that these advances should have resulted in changes to the characteristics of patients with RA participating in clinical trials of the newest therapies. This study determined whether the baseline characteristics of patients with RA enrolled in clinical trials have changed in the past decade versus patients participating in earlier RA studies. Methods: This secondary analysis was based on randomised controlled trials (RCTs) identified in a systematic literature review. Baseline characteristics of patients with RA with inadequate response to conventional synthetic DMARDs were compared between RCTs published in 1999\u20132009 and those published in 2010\u20132017 using random-effects meta-analyses. Results: Forty RCTs were analysed: 22 from 1999\u20132009 and 18 from 2010\u20132017. No significant difference between the two timeframes and no obvious trend over time were observed for age, gender, disease duration, rheumatoid factor status, tender and swollen joint counts, physician and patient global assessments of disease activity, and pain scores. Variability between RCTs was high. Similar results were observed for Disease Activity Scores and Health Assessment Questionnaire-Disability Index scores, but with low variability between RCTs. Conclusion: The baseline characteristics of patients with RA participating in RCTs do not appear to have changed in the last decade despite the availability of new treatments and a different treatment approach. Further research should determine the impact of baseline patient characteristics on patients\u2019 response to RA treatments

The dark recovery rate in the photocycle of the bacterial photoreceptor YtvA is affected by the cellular environment and by hydration

We report thermal recovery kinetics of the lit state into the parental dark state, measured for the blue light-sensing photoreceptor YtvA inside overexpressing E. coli and B. subtilis bacterial cells, performed for the wild type and several mutated proteins. Recovery was followed as a recovery of the fluorescence, as this property is only found for the parental but not for the photochemically generated lit state. When cells were deposited onto a microscope glass plate, the observed thermal recovery rate in the photocycle was found ca. ten times faster in comparison to purified YtvA in solution. When the E. coli or B. subtilis colonies were soaked in an isotonic buffer, the dark relaxation became again much slower and was very similar to that observed for YtvA in solution. The observed effects show that rate constants can be tuned by the cellular environment through factors such as hydration. Copyright

rates of latent tuberculosis infection using different diagnostica test

Background.The interferon−g−release assays (IGRA) are emerging as an attractive alternative to the tuberculin skin test (TST) for the diagnosis of latent tuberculosis infection (LTBI).The absence of a gold standard for LTBI hampers the assessment of any diagnostic test. Methods.In a prospective study,229 patients (mean age 35.5±24.6 y) from different ward of the Hospital (Respiratory Diseases,Dermatology, Rheumatology, Pediatrics, Infectious Diseases, Hematology and Transplant Unit) were simultaneously tested for a suspect of either LTBI or active tuberculosis using all commercially available diagnostics: TST,QuantiFERON−TB Gold (QFT−2G), QuantiFERON−TB Gold In−Tube(QFT−3G) and T−SPOT.TB(TS.TB). Results. 42(18.3%),37(16.2%),59(25.8%) and 79(34.5%) patients were positive with TST,QFT−2G,QFT−3G and TS.TB, respectively.TS.TB(p<0.001) and QFT−3G(p=0.016) provided more positive results than TST, while no difference was found for TST and QFT−2G(p=0.53).All IGRA showed a good overall agreement (TS.TB vs QFT−2G,k=0.55; TS.TB vs QFT−3G,k=0.72;QFT−2G vs QFT−3G, k=0.62). In 22 subjects (9.6%) QFT−3G was positive and QFT−2G negative. Indeterminate results were more frequent with QFT−2G(18.3%) and QFT−3G (12.7%) than with TS.TB(1.3%,p<0.0001). Conclusion. Rates of LTBI as detected by different diagnostic tests may have significant variations. Performances of various IGRA formats were variable in this population

Argyrophilic nucleolar organizer regions and bromodeoxyuridine and h3-thymidine labelling indices in colorectal cancer

The count of argyrophilic nucleolar organizer regions (AgNORs) has been proposed as a useful method for evaluating cell replication in human tumours. The current study was undertaken to compare AgNOR values in colorectal cancers with two better established methods for investigating cell proliferation such as bromodeoxyuridine (BrdUrd) and (3)[H]-thymidine ((3)[H]dT) labelling indices (LIs). Because some concern still exists regarding accuracy and reproducibility of AgNOR quantifying methods, we carried out a control study by independently repeating the same measurements (number, area and area per silver-stained NOR particle) in two centres with different operators and computer-assisted image analysers on 40 colorectal carcinomas. AgNOR values recorded in the two centres were strictly correlated (r = 0.75; P &lt; 0.001 for number; r = 0.62, P &lt; 0.01 for area; r = 0.63, P &lt; 0.001 for area per silver-stained NOR particle) and the range of values were almost identical, Then, AgNOR values were compared with BrdUrd and (3)[H]dT LIs, respectively obtained by in vivo incorporation and in vitro incubation in the same series of colorectal carcinomas. No correlation was found between AgNOR values and BrdUrd or (3)[H]dT LIs. BrdUrd and (3)[H]dT LIs were instead reciprocally significantly correlated, No evident correlation was seen between LIs or AgNOR values and clinico-pathological parameters of the tumour. In conclusion, in colorectal neoplasms, AgNOR values did not appear to relate with more direct parameters of cell proliferation. It follows that AgNOR reliability as a biomarker of cell proliferation remains questionable

Effect of platelet lysate on human cells involved in different phases of wound healing

Background Platelets are rich in mediators able to positively affect cell activity in wound healing. Aim of this study was to characterize the effect of different concentrations of human pooled allogeneic platelet lysate on human cells involved in the different phases of wound healing (inflammatory phase, angiogenesis, extracellular matrix secretion and epithelialization). Methodology/Principal Findings Platelet lysate effect was studied on endothelial cells, monocytes, fibroblasts and keratinocytes, in terms of viability and proliferation, migration, angiogenesis, tissue repair pathway activation (ERK1/2) and inflammatory response evaluation (NFκB). Results were compared both with basal medium and with a positive control containing serum and growth factors. Platelet lysate induced viability and proliferation at the highest concentrations tested (10% and 20% v/v). Whereas both platelet lysate concentrations increased cell migration, only 20% platelet lysate was able to significantly promote angiogenic activity (p&lt;0.05 vs. control), comparably to the positive control. Both platelet lysate concentrations activated important inflammatory pathways such as ERK1/2 and NFκB with the same early kinetics, whereas the effect was different for later time-points. Conclusion/Significance These data suggest the possibility of using allogeneic platelet lysate as both an alternative to growth factors commonly used for cell culture and as a tool for clinical regenerative application for wound healing

Stable and Solution-Processable Cumulenic sp-Carbon Wires: A New Paradigm for Organic Electronics

open12siAcknowledgements. E.G.F. acknowledges the support through the EU Horizon 2020 research and innovation program, H2020-FETOPEN-01-2018-2020 (FET-Open Challenging Current Thinking), “LION-HEARTED”, grant agreement no. 828984. C.S.C. acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program ERC-Consolidator Grant (ERC CoG 2016 EspLORE grant agreement no. 724610, website: www.esplore.polimi.it). R.R.T. acknowledges funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canada Foundation for Innovation (CFI). This work was partially supported by the European Union's H2020-EU.4.b. – Twinning of research institutions “GREENELIT”, grant agreement number 951747. GIWAXS experiments were performed at BL11 NCD-SWEET beamline at ALBA Synchrotron (Spain) with the collaboration of ALBA staff. This work was in part carried out at Polifab, the micro- and nanotechnology centre of the Politecnico di Milano. Open access funding provided by Istituto Italiano di Tecnologia within the CRUI-CARE Agreement.Solution-processed, large-area, and flexible electronics largely relies on the excellent electronic properties of sp2-hybridized carbon molecules, either in the form of π-conjugated small molecules and polymers or graphene and carbon nanotubes. Carbon with sp-hybridization, the foundation of the elusive allotrope carbyne, offers vast opportunities for functionalized molecules in the form of linear carbon atomic wires (CAWs), with intriguing and even superior predicted electronic properties. While CAWs represent a vibrant field of research, to date, they have only been applied sparingly to molecular devices. The recent observation of the field-effect in microcrystalline cumulenes suggests their potential applications in solution-processed thin-film transistors but concerns surrounding the stability and electronic performance have precluded developments in this direction. In the present study, ideal field-effect characteristics are demonstrated for solution-processed thin films of tetraphenyl[3]cumulene, the shortest semiconducting CAW. Films are deposited through a scalable, large-area, meniscus-coating technique, providing transistors with hole mobilities in excess of 0.1&nbsp;cm2V−1s−1, as well as promising operational stability under dark conditions. These results offer a solid foundation for the exploitation of a vast class of molecular semiconductors for organic electronics based on sp-hybridized carbon systems and create a previously unexplored paradigm.openPecorario S.; Scaccabarozzi A.D.; Fazzi D.; Gutierrez-Fernandez E.; Vurro V.; Maserati L.; Jiang M.; Losi T.; Sun B.; Tykwinski R.R.; Casari C.S.; Caironi M.Pecorario S.; Scaccabarozzi A.D.; Fazzi D.; Gutierrez-Fernandez E.; Vurro V.; Maserati L.; Jiang M.; Losi T.; Sun B.; Tykwinski R.R.; Casari C.S.; Caironi M

The nonlinear time-dependent response of isotactic polypropylene

Tensile creep tests, tensile relaxation tests and a tensile test with a constant rate of strain are performed on injection-molded isotactic polypropylene at room temperature in the vicinity of the yield point. A constitutive model is derived for the time-dependent behavior of semi-crystalline polymers. A polymer is treated as an equivalent network of chains bridged by permanent junctions. The network is modelled as an ensemble of passive meso-regions (with affine nodes) and active meso-domains (where junctions slip with respect to their positions in the bulk medium with various rates). The distribution of activation energies for sliding in active meso-regions is described by a random energy model. Adjustable parameters in the stress--strain relations are found by fitting experimental data. It is demonstrated that the concentration of active meso-domains monotonically grows with strain, whereas the average potential energy for sliding of junctions and the standard deviation of activation energies suffer substantial drops at the yield point. With reference to the concept of dual population of crystalline lamellae, these changes in material parameters are attributed to transition from breakage of subsidiary (thin) lamellae in the sub-yield region to fragmentation of primary (thick) lamellae in the post-yield region of deformation.Comment: 29 pages, 12 figure