Correction: Enhanced electrocaloric effect, energy storage density and pyroelectric response from a domain-engineered lead-free BaTi0.91Sn0.08Zr0.01O3 ferroelectric ceramic.

[This corrects the article DOI: 10.1039/D2RA04914G.].

Alterations of oral microbiota and impact on the gut microbiome in type 1 diabetes mellitus revealed by integrated multi-omic analyses.

BACKGROUND: Alterations to the gut microbiome have been linked to multiple chronic diseases. However, the drivers of such changes remain largely unknown. The oral cavity acts as a major route of exposure to exogenous factors including pathogens, and processes therein may affect the communities in the subsequent compartments of the gastrointestinal tract. Here, we perform strain-resolved, integrated meta-genomic, transcriptomic, and proteomic analyses of paired saliva and stool samples collected from 35 individuals from eight families with multiple cases of type 1 diabetes mellitus (T1DM). RESULTS: We identified distinct oral microbiota mostly reflecting competition between streptococcal species. More specifically, we found a decreased abundance of the commensal Streptococcus salivarius in the oral cavity of T1DM individuals, which is linked to its apparent competition with the pathobiont Streptococcus mutans. The decrease in S. salivarius in the oral cavity was also associated with its decrease in the gut as well as higher abundances in facultative anaerobes including Enterobacteria. In addition, we found evidence of gut inflammation in T1DM as reflected in the expression profiles of the Enterobacteria as well as in the human gut proteome. Finally, we were able to follow transmitted strain-variants from the oral cavity to the gut at the individual omic levels, highlighting not only the transfer, but also the activity of the transmitted taxa along the gastrointestinal tract. CONCLUSIONS: Alterations of the oral microbiome in the context of T1DM impact the microbial communities in the lower gut, in particular through the reduction of "mouth-to-gut" transfer of Streptococcus salivarius. Our results indicate that the observed oral-cavity-driven gut microbiome changes may contribute towards the inflammatory processes involved in T1DM. Through the integration of multi-omic analyses, we resolve strain-variant "mouth-to-gut" transfer in a disease context. Video Abstract.

Enhanced electrocaloric effect, energy storage density and pyroelectric response from a domain-engineered lead-free BaTi0.91Sn0.08Zr0.01O3 ferroelectric ceramic.

A BaTi0.91Sn0.08Zr0.01O3 (BTSZ) ceramic was prepared by a conventional solid-state reaction method. Its structural, dielectric, ferroelectric, and pyroelectric properties were carefully studied. The Rietveld refinement was used to characterize the structural proprieties of the synthesized ceramic. The microstructure was observed by scanning electron microscopy. Phase transitions observed in the temperature dependent dielectric permittivity (ε r-T and tan δ-T) showed a transition close to room temperature, resulting in improved piezoelectric, pyroelectric and electrocaloric performance. In addition, it was found that an electric field poling process changed the character of ε r-T and tan δ-T plots. Resonance modes in the polarized state, where maximum power transmission was achieved, were observed in the impedance spectrum. The extra-slim hysteresis loops revealed a relatively low coercive field and hysteresis loss related to the diffuse phase transition, which can significantly improve energy storage efficiency up to 75% at 100 °C. To characterize the electrocaloric effect (ECE), indirect and direct methods based on the thermodynamic approach were used. Both methods results showed good consistency and revealed a large ECE peak evolving along the phase diagram. Furthermore, pyroelectric figures of merit (FOMs) for voltage responsivity (F v), current responsivity (F i), energy harvesting (F E), new energy harvesting and detectivity (F d) were calculated. Finally, thermal energy harvesting (N D) was determined by using the Olsen cycle. The obtained maximum N D was 233.7 kJ m-3 when the Olsen cycle operated at 25-100 °C and 0-30 kV cm-1. This study introduces not only a technique to produce a high performance ceramic for refrigeration devices, but also broadens the range of applications for BT-based lead-free ferroelectrics beyond actuators, sensors, and energy harvesting to solid-state cooling.

The dark side of SARS-CoV-2 rapid antigen testing: screening asymptomatic patients.

Several reports showed SARS-CoV-2 rapid antigen tests (RATs) performances among COVID-19 symptomatic subjects in outpatient settings during periods of highest incidence of infections and high rates of hospital admissions, but few data are present for asymptomatic patients. We investigated the role of RATs in an emergency department, as a novel screening tool before admission for COVID-19 asymptomatic patients. A total of 116 patients were screened on admission in a 250-bed community hospital in Morges, Switzerland. RAT detected 2/7 RT-PCR-positive patients and delivered two false-positive results. These data suggest the non-fiability of RATs screening in this clinical scenario.

Heterosynaptic facilitation of mechanical nociceptive input is dependent on the frequency of conditioning stimulation.

High-frequency burstlike electrical conditioning stimulation (HFS) applied to human skin induces an increase in mechanical pinprick sensitivity of the surrounding unconditioned skin (a phenomenon known as secondary hyperalgesia). The present study assessed the effect of frequency of conditioning stimulation on the development of this increased pinprick sensitivity in humans. In a first experiment, we compared the increase in pinprick sensitivity induced by HFS, using monophasic non-charge-compensated pulses and biphasic charge-compensated pulses. High-frequency stimulation, traditionally delivered with non-charge-compensated square-wave pulses, may induce a cumulative depolarization of primary afferents and/or changes in pH at the electrode-tissue interface due to the accumulation of a net residue charge after each pulse. Both could contribute to the development of the increased pinprick sensitivity in a frequency-dependent fashion. We found no significant difference in the increase in pinprick sensitivity between HFS delivered with charge-compensated and non-charge-compensated pulses, indicating that the possible contribution of charge accumulation when non-charge-compensated pulses are used is negligible. In a second experiment, we assessed the effect of different frequencies of conditioning stimulation (5, 20, 42, and 100 Hz) using charge-compensated pulses on the development of increased pinprick sensitivity. The maximal increase in pinprick sensitivity was observed at intermediate frequencies of stimulation (20 and 42 Hz). It is hypothesized that the stronger increase in pinprick sensitivity at intermediate frequencies may be related to the stronger release of substance P and/or neurokinin-1 receptor activation expressed at lamina I neurons after C-fiber stimulation.NEW & NOTEWORTHY Burstlike electrical conditioning stimulation applied to human skin induces an increase in pinprick sensitivity in the surrounding unconditioned skin (a phenomenon referred to as secondary hyperalgesia). Here we show that the development of the increase in pinprick sensitivity is dependent on the frequency of the burstlike electrical conditioning stimulation.

The oriented processes for extraction and recovery of paracetamol compound across different affinity polymer membranes. Parameters and mechanisms.

Membrane processes represent one of the most promising technologies for separation and extraction in modern industries, because they have several advantages. Today these processes are an important research topic, including affinity polymer membranes that are highly efficient for oriented processes. Three affinity polymer membrane types containing lipophilic compounds, methyl cholate (MC) and cholic acid (CA) as extractive agents were prepared and characterized. They have been used to extract active ingredient paracetamol (acetaminophen), from concentrated solutions (0.08-0.01M). Substrate acetaminophen is an important active ingredient and its recovery as a pure compound, is very useful for the pharmaceutical industry. These affinity polymer membranes were adopted to perform experiments on a facilitated extraction process of this substrate at different medium acidities and temperatures. Macroscopic parameters, permeabilities (P) and initial fluxes (J0) for a facilitated extraction of this substrate through each membrane were determined. The results indicate that values of initial fluxes (J0) of the extracted substrate are related to its initial concentration C0 by a saturation law, which allowed to determine microscopic parameters, apparent diffusion coefficients (D*) and association constants (Kass) of formed entity (substrate - extractive agent) (ST). The results show a clear influence of temperature and acidity factors on the evolution of these parameters and membrane performances in this studied process. Activation parameters (Ea, ΔH≠, and ΔS≠) were determined and the values indicate that high performances of these membrane types are certainly related to the movement nature of the substrate across the organic phase, and the structures of the substrate and the extractive agent.

Water sorption behaviour of two series of PHA/montmorillonite films and determination of the mean water cluster size.

Biodegradable polyester-based films constituted of poly(hydroxyalkanoates) (PHA) were successfully extruded with various Cloisite 30B contents. The morphology was highly dependent on the matrix, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate), the polymer crystalline phase fraction, the matrix/nanoclay interfacial regions as well as the nanoclay content. Water vapour resistance was investigated through sorption kinetics, isotherms, modelling aspect, and diffusivity. A typical sigmoid-shaped isotherm was obtained in every case. It emerges that the nanoclay highly contributed to the increase of water solubility of matrices. The dependence of polymer crystallinity on the affinity of the nanocomposite films for water was highlighted. Thermodynamic and kinetic contributions of the sorption process were also correlated with the film morphology. According to the matrix used, water diffusivity in films was differently impacted by the sorbed water amount. The access of sorbed water molecules within films was examined through a mathematical modelling approach and the deduced mean cluster size of water vs. its activity was corroborated by sorption kinetics.

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) based nanocomposites: influence of the microstructure on the barrier properties.

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB-co-4HB) films containing various contents of organo-modified montmorillonite C30B nanoclays were prepared by melt intercalation. Wide angle X-ray diffraction measurements and transmission electron microscopy observations evidenced aggregated and intercalated structures with individual nanoclay platelets in the nanocomposites and an orientation of nanoclays. Differential scanning calorimetry measurements showed that the nanoclay did not influence the crystalline structure of the matrix because it is mainly located in the polymer amorphous phase. The influence of the filler on the barrier properties of the film was evaluated by water diffusion, gas permeation (CO2, N2, O2) and liquid water sorption measurements. A decrease of the N2 permeability was measured due to the tortuosity effect of the filler associated with a decrease of the solubility within the matrix. The influence of the filler was more marked for O2 due to the larger decrease of O2 solubility. In contrast, the CO2 permeability increased whatever the filler content because of a facilitated transport mechanism due induced by the presence of quaternary ammonium cations on the C30B surface. The decrease of the water permeability with the filler was explained by a competition between the kinetic (diffusivity) and thermodynamic (solubility) contributions defining the permeability process.

Pressure impact of autoclave treatment on water sorption and pectin composition of flax cellulosic-fibres.

The tensile properties of flax fibres might permit them to be used in composites as reinforcement in organic resin, as long as their mechanical properties are reproducible and their water sorption are reduced. In this study, to minimise the variability of mechanical properties, several samples of flax fibres were blended as a non-woven fabric. In order to reduce the water absorption of this non-woven technical fibres, an autoclave treatment was performed which was expected to remove the pectins and then to reduce the water sorption on their negative charges. The impact of autoclave pressure (0.5, 1 and 2 bars) on water sorption was investigated by using a gravimetric static equilibrium method. The Park model based on the three sorption modes: Langmuir, Henry's law and clustering, was successfully used to simulate the experimental sorption data. The lowest pressure treatments impacted only the Langmuir contribution while the 2 bar autoclave-treatment positively impacted the water resistance in the core of fibres by reducing Henry's absorption rate. This was shown to be related to the chemical modifications at the surface and in the core of fibres. A schematic model is presented relating the water sorption and the pectic composition of the fabric.

Pectinase treatments on technical fibres of flax: Effects on water sorption and mechanical properties.

This study is focused on enzymatically upgrading the functional properties of flax fibres. Green flax fibres were treated with a polygalacturonase and a pectate lyase (PaL) and their properties were compared with dew-retted fibres. Morphological observations, vapour-sorption analyses and mechanical measurements showed that PaL-treatment was able not only to mime retting in terms of bundle division, but also to improve the mechanical properties of technical fibres. Conversely, these properties were shifted down after the polygalacturonase treatment, mainly due to the presence of contaminating glycanases. At the level of the elementary fibres, nanoindentation data indicated the highest stiffness of the secondary wall for PaL-treated fibres. The tensile properties exhibited equal, but moderate values of the Young's modulus (∼37±14GPa) and breaking strength (∼650±300MPa) for retted and PaL-treated fibres; we hypothesize an impact of the growth conditions on the fibre chemical structure with an excess of matrix pectins compared to the amount of glucomannan coating the cellulose microfibrils.

Effect of chemical treatments on water sorption and mechanical properties of flax fibres.

In this work, in order to improve the adhesion between a polyester matrix (unsaturated polyester resin) and flax fibres (Linum usitatissimum L.) and to increase their moisture resistance, chemical surface treatments have been used. These different treatments were performed with maleic anhydride (MA), acetic anhydride (Ac), silane (Si) and styrene (S). The modified flax fibres were characterized by means of infrared spectroscopy and surface energy analysis. The effect of these treatments on water sorption was investigated by using a gravimetric static equilibrium method. Water sorption isotherms were derived from kinetic data. The Park model based on the three sorption modes: Langmuir, Henry's law and clustering, was successfully used to simulate the experimental sorption data. It was found that the (Ac) and particularly (S) treatments reduced overall water uptake of flax fibres. We show that tensile modulus, breaking strength and breaking strain depend on the chemical treatment used.

A variant in long palate, lung and nasal epithelium clone 1 is associated with cholera in a Bangladeshi population.

Vibrio cholerae causes a dehydrating diarrheal illness that can be rapidly fatal in the absence of specific treatment. The organism is an historic scourge and, like similar infectious diseases, may have influenced the evolution of the human genome. We report here the results of the first candidate gene association study of cholera. In a family-based study of 76 pedigrees from Dhaka, Bangladesh, we evaluated the association between cholera and five candidate genes-the cystic fibrosis transmembrane receptor; lactoferrin; long palate, lung and nasal epithelium clone 1 (LPLUNC1); estrogen-related receptor alpha and calcium-activated chloride channel 1. We found a significant association with a marker in the promoter region of LPLUNC1 (rs11906665), a member of a family of evolutionarily conserved innate immunity proteins. An earlier microarray-based study of duodenal biopsies showed significantly increased expression of LPLUNC1 in cholera patients compared with healthy control subjects. Our results suggest that variation in host innate immune responses may influence the outcome of exposure to V. cholerae in an endemic setting.

Respiratory infections associated with nontuberculous mycobacteria in non-HIV patients.

The incidence of nontuberculous mycobacteria (NTM) pulmonary diseases in HIV-negative patients was studied prospectively from January 1, 2001 to December 31, 2003 by 32 sentinel sites distributed throughout France. In total, 262 patients who yielded NTM isolates from respiratory clinical specimens, met the bacteriological, radiological and clinical criteria established by the American Thoracic Society for NTM respiratory disease. Among the 262 NTM isolates, 234 were slow-growing mycobacteria (125 Mycobacterium avium-intracellulare complex (MAC), 66 M. xenopi, 34 M. kansasii) and 28 were rapidly growing mycobacteria (25 M. abscessus complex). In the Paris area, M. xenopi was the most frequently isolated species, followed by MAC. Most patients (>50%), except those with M. kansasii, had underlying predisposing factors such as pre-existing pulmonary disease or immune deficiency. Asthenia, weight loss, chronic cough and dyspnoea were the most common clinical symptoms. The classical radiological appearance of NTM infections was indistinguishable from that observed in patients with pulmonary tuberculosis. In summary, the incidence of nontuberculous mycobacteria pulmonary infections in HIV-negative patients was estimated at 0.74, 0.73 and 0.72 cases per 100,000 inhabitants in 2001, 2002 and 2003, respectively.

Investigations on ferroelectric PMN-PT and PZN-PT single crystals ability for power or resonant actuators.

Ferroelectric single crystals of PZN-PT and PMN-PT exhibit outstanding properties: high charge coefficient (dij), high coupling factor (kij) and high strain levels under DC fields. Besides, their mechanical quality factor is believed to be low. Their usefulness for non-resonant or large bandwidth transducers has therefore been previously investigated. However, few studies have been devoted to the dielectric and mechanical losses of single crystals and to their stability under high levels of excitations (electric fields, temperature and mechanical stress). A knowledge and understanding of such performances is needed to determine whether single crystals are suitable materials for power or resonant transducers. In this work, losses and non-linearity versus external excitations are investigated. Dielectric losses and mechanical losses are measured versus electric field for different compositions, orientations. The evolution of d33 and epsilonT33 are obtained versus electric field and temperature for the longitudinal mode. Strain and hysteresis versus sweep mode (up and down) are measured near the resonance frequency using a laser Doppler vibrometer.

Emergence of nosocomial Pseudomonas aeruginosa colonization/infection in pregnant women with preterm premature rupture of membranes and in their neonates.

The epidemiology, risk factors, maternal and neonatal outcomes of nosocomial Pseudomonas aeruginosa acquisition in preterm premature rupture of membranes were analysed. Of 63 women receiving antibiotic prophylaxis with co-amoxiclav, 11 acquired P. aeruginosa vaginal carriage with a median delay of 15 days (6-42) i.e. an incidence of 8.94 per 1000 days of expectant management. Five neonates born to 11 positive mothers were colonized or infected, three of whom died of fulminant sepsis. The duration of antibiotic treatment and multiple pregnancy were identified as independent risk factors. The epidemiological investigation revealed a vertical transmission between mothers and neonates, and suggested selective pressure of antibiotic treatment.

Direct measurement of the interactions of glycosaminoglycans and a heparin decasaccharide with the malaria circumsporozoite protein.

Circumsporozoite (CS) protein is a predominant surface antigen of malaria sporozoites, the infective form of the parasite, and has been used for making anti-malaria vaccines. For the first time we have examined the interaction of CS protein with various glycosaminoglycans in real time using surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC). Heparin was the best binder among the glycosaminoglycans tested and bound to CS protein with nanomolar affinity. Using purified and structurally defined small heparin oligosaccharides, we identified a decasaccharide to be the minimum sized CS protein-binding sequence. In an indirect competition assay, this decasaccharide blocked the CS protein interaction with HepG2 cells with an ID(50) of less than 60 nM. The decasaccharide has a structure commonly found in hepatic heparan sulfate, and the same sequence has recently been shown to bind specifically to apolipoprotein E. Examination of porcine liver heparan sulfate in this indirect competition assay showed that it and heparin were the only glycosaminoglycans that could effectively block CS protein interaction with HepG2 cells in culture. These data support the hypothesis that the invasion of liver cells by the parasite shares a common mechanism with the hepatic uptake of lipoprotein remnants from the blood.

Certain high molecular weight heparin chains have high affinity for vitronectin.

Vitronectin is a 70-kDa protein that is found in both the extracellular matrix as well as serum. Vitronectin is one of the few proteins that regulates both the complement and the coagulation systems. Heparin is known to bind to vitronectin. Review of the literature reveals apparently conflicting outcomes of the interaction of heparin, vitronectin, and the complement system. Previous studies demonstrated that heparin diminishes vitronectin inhibition of complement activity. Numerous studies have also demonstrated that heparin exerts a net inhibitory effect on complement. We used two dimensional affinity resolution electrophoresis (2DARE) to examine this apparent paradox. 2DARE allowed simultaneous determination of binding affinity of heparin for vitronectin as well as the M(r) of the heparin species. In the 2DARE experiment, the interaction of heparin with vitronectin caused retardation of the movement of the heparin through the tube gel in the first dimension. The degree of the retardation of movement was used to calculate the approximate K(d) of that interaction. The heparin from the tube gel was then subjected to a second dimension electrophoresis to determine the M(r) of the heparin. 2DARE analysis of the interaction of heparin with vitronectin clearly demonstrated that a sub-population of heparin chains with M(r) > 8000 bound vitronectin with high affinity whereas most high M(r) chains and all lower M(r) chains showed little to no affinity for vitronectin. Our findings are consistent with the hypothesis that a unique binding domain exists in certain heparin chains for vitronectin.

Molecular identification of TEM-1 beta-lactamase in a Pasteurella multocida isolate of human origin.

Two clinical strains of Pasteurella multocida were isolated from an HIV-infected patient who developed arthritis. Strain FB-1, which was isolated from a dog-bite wound, was resistant to narrow-spectrum penicillins. The second strain, FB-2, which was present in blood cultures as well as the dog-bite wound, was susceptible to all beta-lactam agents. Arbitrarily primedpolymerase chain reaction and pulsed-field gel electrophoresis revealed that these two isolates were genetically indistinguishable. 16S rDNA gene sequencing facilitated identification at the subspecies level. Amoxicillin resistance determinant was located on a highly unstable 4.3-kb plasmid, pFAB-1. Isoelectrofocusing and polymerase chain reaction amplification followed by sequencing revealed the presence of a pI 5.4 TEM-1 beta-lactamase. This description is the first of a TEM-1 Beta-lactamase' in a Pasteurella multocida strain of human origin.