Isabelle D. Wessely  Yannick Matt  Qi An  Stefan Brse  Manuel Tsotsalas 《RSC advances》2021,11(44):27714

Porous organic polymers (POPs) show enormous potential for applications in separation, organic electronics, and biomedicine due to the combination of high porosity, high stability, and ease of functionalisation. However, POPs are usually insoluble and amorphous materials making it very challenging to obtain structural information. Additionally, important parameters such as the exact molecular structure or the crosslinking degree are largely unknown, despite their importance for the final properties of the system. In this work, we introduced the reversible multi-fold nitroxide exchange reaction to the synthesis of POPs to tune and at the same time follow the crosslinking degree in porous polymer materials. We synthesised three different POPs based on the combination of linear, trigonal, and tetrahedral alkoxyamines with a tetrahedral nitroxide. We could show that modulating the equilibrium in the nitroxide exchange reaction, by adding or removing one nitroxide species, leads to changes in the crosslinking degree. Being able to modulate the crosslinking degree in POPs allowed us to investigate both the influence of the crosslinking degree and the structure of the molecular components on the porosity. The crosslinking degree of the frameworks was characterised using EPR spectroscopy and the porosity was determined using argon gas adsorption measurements. To guide the design of POPs for desired applications, our study reveals that multiple factors need to be considered such as the structure of the molecular building blocks, the synthetic conditions, and the crosslinking degree.

We synthesised three different POPs via a nitroxide exchange reaction and modulated their crosslinking degree. That allowed us to investigate the influence of the crosslinking degree and the structure of the molecular components on the porosity.

Various approaches to synthesise porous organic polymers (POPs)^1–3 and conjugated microporous polymers (CMPs)^4,5 have been developed to form extremely stable but at the same time highly porous solids based on simple organic building blocks.^6,7 The organic nature allows for functionalisation of the materials using organic chemistry, while the high porosity makes the active components accessible throughout the entire material.⁸ The combination of high porosity, high stability, and ease of functionalisation results in the enormous potential of POPs for applications in separation, organic electronics, and biomedicine.^2,9–14 However, unlike the related covalent organic frameworks (COFs),^15–20 metal–organic frameworks (MOFs)^21,22 or porous coordination polymers (PCPs),²³ the synthesis of POPs and CMPs is based on irreversible reactions, which leads to insoluble and amorphous materials and makes it very challenging to obtain structural information. Additionally, important parameters such as the exact molecular structure or the crosslinking degree are largely unknown, despite their unarguably large influence on the final properties of the system.^24,25To investigate the molecular structure of the organic linkers between the centres of two similar CMP materials, the group of Bunz and co-workers introduced molecular building blocks that were modified with digestible groups or cores, by substituting carbon with tin as the central atom.²⁴ This tin centre can be digested, resulting in molecular fragments of the frameworks, which were analysed using nuclear magnetic resonance (NMR) spectroscopy. The obtained fragments show a surprisingly varied chemical composition of these networks.²⁴ In a previous study, we could show that the introduction of digestible germanium nodes in one of the building blocks of POPs can also be used for partial disruption of the framework and therefore causing a decrease or allow tuning of the porosity.²⁵ In another approach, we introduced a poly(disulfide) hyper-crosslinked polymer, which can be surface modified using unreacted thiol functions on the surface of the material.²⁶ Digestion of the samples helped to quantify the functionalisation. Employing digestible crosslinker or nodes is an attractive approach to gain insight into the structure or functionalisation of the frameworks. However, it requires the destruction of the sample and does not allow to modulate or tune the crosslinking degree reversibly in one particular system.In order to tune and at the same time follow the crosslinking degree in porous polymer materials, we introduce the reversible multi-fold nitroxide exchange reaction to the synthesis of POPs. The nitroxide exchange reaction has been used in material science for self-assembly of polymer materials²⁷ or micron-sized crystals,²⁸ for surface functionalisation,²⁹ or introducing self-healing properties to materials.³⁰ In addition, the combination of light-sensitive alkoxyamines was employed in surface coating³¹ or the creation of systems out of their equilibrium.³² The radical nature of the involved nitroxide species allows to follow the progress of the reaction and to directly determine the crosslinking degree of the final material using fluorescence spectroscopy^33,34 and electron paramagnetic resonance (EPR) spectroscopy.^35,36 The dynamic nature of the nitroxide exchange reaction allowed us to tune the crosslinking degree of the materials by varying the ratio of the two nitroxide species involved in the reaction and thereby modulating the equilibrium conditions (see Fig. 1).Open in a separate windowFig. 1Dynamic equilibrium in the nitroxide exchange reaction using two different nitroxide species, TEMPO (red) and isoindoline (green). The free nitroxide radical species are electron paramagnetic resonance (EPR) active, while the bound species are EPR silent.Next to the crosslinking degree, also the structure, rigidity, and the intrinsic free volume of the molecular components of POPs or CMPs play an important role to obtain porosity in the final material.⁶ Cooper and co-workers showed the importance of monomer design for the pore size and surface area of CMPs by systematically varying the strut length in a series of molecular building blocks.³⁷In order to study the influence of both the molecular structure and the crosslinking degree on the porosity of the final material, we produced three different POPs based on the combination of linear, trigonal, and tetrahedral alkoxyamines with tetrahedral nitroxides. We characterised the frameworks using EPR spectroscopy and argon gas adsorption measurements to determine the crosslinking degree and porosity. Furthermore, we could show that modulating the equilibrium in the nitroxide exchange reaction, by adding or removing one nitroxide species, leads to changes in the crosslinking degree and investigated this influence on the porosity of the frameworks.  相似文献   

    

Yannick Le Hénaff  Stephane Héas 《Sociology of health & illness》2020,42(1):65-79

Using the biographical disruption literature, this article examines how the experience of illness – in this case, pemphigus – reconfigures engagement in leisure activities, and how these activities are integrated into the biographies of persons with a rare chronic illness. Among the changes imposed by the illness, leisure activities are especially enlightening, as they primarily depend on the body. The article is based on a study of 50 interviews of persons with pemphigus, a rare and chronic dermatological disorder. The ways in which they relate to leisure activities give a new perspective on biographical disruption. The first striking observation is how diverse they are: illness does not level social differences or lived experience, and can even further consolidate commitment to engagements. We identified four types of engagement in leisure activities: disengagement, which reveals biographical disruption; adapted engagement, leading individuals toward low-risk physical activities; engagement in medicalised normalisation; and salutary engagement.  相似文献   

    

Eva Wittenmeier  Irene Schmidtmann  Pascal Heese  Pascal Müller  Nicole Didion  Marc Kriege  Yannick Komorek  Nina Pirlich 《Paediatric anaesthesia》2023,33(11):923-929

Introduction

Continuously assessing the oxygenation levels of patients to detect and prevent hypoxemia can be advantageous for safe anesthesia, especially in neonates and small infants. The oxygen reserve index (ORI) is a new parameter that can assess oxygenation through a relationship with arterial oxygen partial pressure (PaO₂). The aim of this study was to examine whether the ORI provides a clinically relevant warning time for an impending SpO₂ (pulse oximetry hemoglobin saturation) reduction in neonates and small infants.

Methods

ORI and SpO₂ were measured continuously in infants aged <2 years during general anesthesia. The warning time and sensitivity of different ORI alarms for detecting impending SpO₂ decrease were calculated. Subsequently, the agreement of the ORI and PaO₂ with blood gas analyses was assessed.

Results

The ORI of 100 small infants and neonates with a median age of 9 months (min–max, 0–21 months) and weight of 8.35 kg (min–max, 2–13 kg) were measured. For the ORI/PaO₂ correlation, 54 blood gas analyses were performed. The warning time and sensitivity of the preset ORI alarm during the entire duration of anesthesia were 84 s (25th–75th percentile, 56–102 s) and 55% (95% CI 52%–58%), and those during anesthesia induction were 63 s (40–82 s) and 56% (44%–68%), respectively. The positive predictive value of the preset ORI alarm were 18% (95% CI 17%–20%; entire duration of anesthesia) and 27% (95% CI 21%–35%; during anesthesia induction). The agreement of PaO₂ intervals with the ORI intervals was poor, with a kappa of 0.00 (95% CI = [−0.18; 0.18]). The weight (p = .0129) and height (p = .0376) of the infants and neonates were correlated to the correct classification of the PaO₂ interval with the ORI interval.

Conclusions

The ORI provided an early warning time for detecting an impending SpO₂ decrease in small infants and neonates in the defined interval in this study. However, the sensitivity of ORI to forewarn a SpO₂ decrease and the agreement of the ORI with PaO₂ intervals in this real-life scenario were too poor to recommend the ORI as a useful early warning indicator for this age group.  相似文献   

    

Franois-Xavier Briand  Eric Niqueux  Audrey Schmitz  Claire Martenot  Martine Cherbonnel  Pascale Massin  Florian Kerbrat  Marina Chatel  Carole Guillemoto  Cecile Guillou-Cloarec  Katell Ogor  Aurlie Le Prioux  Chantal Alle  Vronique Beven  Edouard Hirchaud  Yannick Blanchard  Axelle Scoizec  Sophie Le Bouquin  Nicolas Eterradossi  Batrice Grasland 《Emerging infectious diseases》2021,27(2):508

We detected 3 genotypes of highly pathogenic avian influenza A(H5N8) virus in France during winter 2016–17. Genotype A viruses caused dramatic economic losses in the domestic duck farm industry in southwestern France. Our phylogenetic analysis suggests that genotype A viruses formed 5 distinct geographic clusters in southwestern France. In some clusters, local secondary transmission might have been started by a single introduction. The intensity of the viral spread seems to correspond to the density of duck holdings in each production area. To avoid the introduction of disease into an unaffected area, it is crucial that authorities limit the movements of potentially infected birds.  相似文献   

    

Lisa Kinget  Oliver Bechter  Kevin Punie  Philip R. Debruyne  Hilde Brems  Paul Clement  Eduard Roussel  Yannick Van Herck  Maarten Albersen  Marcella Baldewijns  Patrick Schffski  Benoit Beuselinck 《Current oncology (Toronto, Ont.)》2021,28(5):3227

In recent years, immune checkpoint inhibitors (ICPI) have become widely used for multiple solid malignancies. Reliable predictive biomarkers for selection of patients who would benefit most are lacking. Several tumor types with somatic or germline alterations in genes involved in the DNA damage response (DDR) pathway harbor a higher tumor mutational burden, possibly associated with an increased tumoral neoantigen load. These neoantigens are thought to lead to stronger immune activation and enhanced response to ICPIs. We present a series of seven patients with different malignancies with germline disease-associated variants in DDR genes (BRCA1, BRCA2, CHEK2) responding favorably to ICPIs.  相似文献   

    

Ruben F. Kranenburg  Joshka Verduin  Renee de Ridder  Yannick Weesepoel  Martin Alewijn  Marcel Heerschop  Peter H.J. Keizers  Annette van Esch  Arian C. van Asten 《Drug testing and analysis》2021,13(5):1054-1067

Handheld Raman spectroscopy is an emerging technique for rapid on-site detection of drugs of abuse. Most devices are developed for on-scene operation with a user interface that only shows whether cocaine has been detected. Extensive validation studies are unavailable, and so are typically the insight in raw spectral data and the identification criteria. This work evaluates the performance of a commercial handheld Raman spectrometer for cocaine detection based on (i) its performance on 0–100 wt% binary cocaine mixtures, (ii) retrospective comparison of 3,168 case samples from 2015 to 2020 analyzed by both gas chromatography–mass spectrometry (GC–MS) and Raman, (iii) assessment of spectral selectivity, and (iv) comparison of the instrument's on-screen results with combined partial least square regression (PLS-R) and discriminant analysis (PLS-DA) models. The limit of detection was dependent on sample composition and varied between 10 wt% and 40 wt% cocaine. Because the average cocaine content in street samples is well above this limit, a 97.5% true positive rate was observed in case samples. No cocaine false positives were reported, although 12.5% of the negative samples were initially reported as inconclusive by the built-in software. The spectral assessment showed high selectivity for Raman peaks at 1,712 (cocaine base) and 1,716 cm⁻¹ (cocaine HCl). Combined PLS-R and PLS-DA models using these features confirmed and further improved instrument performance. This study scientifically assessed the performance of a commercial Raman spectrometer, providing useful insight on its applicability for both presumptive detection and legally valid evidence of cocaine presence for law enforcement.  相似文献   

    

Clarisse Uwizeye  Margaret Mars Brisbin  Benoit Gallet  Fabien Chevalier  Charlotte LeKieffre  Nicole L. Schieber  Denis Falconet  Daniel Wangpraseurt  Lukas Schertel  Hryhoriy Stryhanyuk  Niculina Musat  Satoshi Mitarai  Yannick Schwab  Giovanni Finazzi  Johan Decelle 《Proceedings of the National Academy of Sciences of the United States of America》2021,118(27)

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Willemijn F.B. van der Does MD  Charlotte A. Houck MD  Annejet Heida MD  Mathijs S. van Schie MSc  Frank R.N. van Schaagen MD  Yannick J.H.J. Taverne MD  PhD  Ad J.J.C. Bogers MD  PhD  Natasja M.S. de Groot MD  PhD 《Journal of cardiovascular electrophysiology》2021,32(4):903-912

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Burcu Gunes  Yannick Jaquet  Laura Snchez  Rebecca Pumarino  Declan McGlade  Brid Quilty  Anne Morrissey  Zahra Gholamvand  Kieran Nolan  Jenny Lawler 《Materials》2021,14(21)

The remarkable adsorption capacity of graphene-derived materials has prompted their examination in composite materials suitable for deployment in treatment of contaminated waters. In this study, crosslinked calcium alginate–graphene oxide beads were prepared and activated by exposure to pH 4 by using 0.1M HCl. The activated beads were investigated as novel adsorbents for the removal of organic pollutants (methylene blue dye and the pharmaceuticals famotidine and diclofenac) with a range of physicochemical properties. The effects of initial pollutant concentration, temperature, pH, and adsorbent dose were investigated, and kinetic models were examined for fit to the data. The maximum adsorption capacities q_max obtained were 1334, 35.50 and 36.35 mg g⁻¹ for the uptake of methylene blue, famotidine and diclofenac, respectively. The equilibrium adsorption had an alignment with Langmuir isotherms, while the kinetics were most accurately modelled using pseudo- first-order and second order models according to the regression analysis. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated and the adsorption process was determined to be exothermic and spontaneous.  相似文献   

    

Michle Bengue  Pauline Ferraris  Jonathan Barthelemy  Cheikh Tidiane Diagne  Rodolphe Hamel  Florian Ligeois  Antoine Nougairde  Xavier de Lamballerie  Yannick Simonin  Julien Pompon  Sara Salinas  Dorothe Miss 《Viruses》2021,13(3)

Mayaro virus (MAYV) and chikungunya virus (CHIKV) are known for their arthrotropism, but accumulating evidence shows that CHIKV infections are occasionally associated with serious neurological complications. However, little is known about the capacity of MAYV to invade the central nervous system (CNS). We show that human neural progenitors (hNPCs), pericytes and astrocytes are susceptible to MAYV infection, resulting in the production of infectious viral particles. In primary astrocytes, MAYV, and to a lesser extent CHIKV, elicited a strong antiviral response, as demonstrated by an increased expression of several interferon-stimulated genes, including ISG15, MX1 and OAS2. Infection with either virus led to an enhanced expression of inflammatory chemokines, such as CCL5, CXCL10 and CXCL11, whereas MAYV induced higher levels of IL-6, IL-12 and IL-15 in these cells. Moreover, MAYV was more susceptible than CHIKV to the antiviral effects of both type I and type II interferons. Taken together, this study shows that although MAYV and CHIKV are phylogenetically related, they induce different types of antiviral responses in astrocytes. This work is the first to evaluate the potential neurotropism of MAYV and shows that brain cells and particularly astrocytes and hNPCs are permissive to MAYV, which, consequently, could lead to MAYV-induced neuropathology.  相似文献