In this communication we present a detailed study of Nafion™ composite membranes containing different amounts of nanosized sulfated titania particles, synthesized through an optimized one-step ...synthesis procedure. Functional membrane properties, such as ionic exchange capacity and water uptake (WU) ability will be described and discussed, together with thermal analysis, atomic force microscopy and Raman spectroscopy data. Also electrochemical properties such as proton conductivity and performances in hydrogen fuel cells will be presented. It has been demonstrated that a critical concentration of filler particles can boost the fuel cell performance at low humidification, exhibiting a significant improvement of the maximum power and current density delivered under 30% low-relative humidity (RH) and 70 °C with respect to bare Nafion™-based systems.
A large number of nano-sized oxides have been studied in the literature as fillers for polymeric membranes, such as Nafion
. Superacidic sulfated oxides have been proposed and characterized. Once ...incorporated into polymer matrices, their beneficial effect on peculiar membrane properties has been demonstrated. The alteration of physical-chemical properties of composite membranes has roots in the intermolecular interaction between the inorganic filler surface groups and the polymer chains. In the attempt to tackle this fundamental issue, here we discuss, by a multi-technique approach, the properties of a nanosized sulfated titania material as a candidate filler for Nafion membranes. The results of a systematic study carried out by synchrotron X-ray diffraction, transmission electron microscopy, thermogravimetry, Raman and infrared spectroscopies are presented and discussed to get novel insights about the structural features, molecular properties, and morphological characteristics of sulphated TiO₂ nanopowders and composite Nafion membranes containing different amount of sulfated TiO₂ nanoparticles (2%, 5%, 7%
/
).
Solid polymer electrolytes, in the form of membranes, offering high chemical and mechanical stability, while maintaining good ionic conductivity, are envisaged as a possible solution to improve ...performances and safety in different lithium cell configurations. In this work, we designed and prepared systems formed using innovative nanocomposite polymer membranes, based on high molecular weight poly(ethylene oxide) (PEO) and silica nanopowders, produced by the electrospinning technique. These membranes were subsequently gelled with solutions based on aprotic ionic liquid, carbonate solvents, and lithium salt. The addition of polysulfide species to the electrolyte solution was also considered, in view of potential applications in lithium-sulfur cells. The morphology of the electrospun pristine membranes was evaluated using scanning electron microscopy. Stability and thermal properties of pristine and gelled systems were investigated uisng differential scanning calorimetry and thermal gravimetric analysis. Electrochemical impedance spectroscopy was used to determine the conductivity of both swelling solutions and gelled membranes, allowing insight into the ion transport mechanism within the proposed composite electrolytes.
Recent studies have suggested that addition of electrically conductive biochar particles is an effective strategy to improve the methanogenic conversion of waste organic substrates, by promoting ...syntrophic associations between acetogenic and methanogenic organisms based on interspecies electron transfer processes. However, the underlying fundamentals of the process are still largely speculative and, therefore, a priori identification, screening, and even design of suitable biochar materials for a given biotechnological process are not yet possible.
Here, three charcoal-like products (i.e., biochars) obtained from the pyrolysis of different lignocellulosic materials, (i.e., wheat bran pellets, coppiced woodlands, and orchard pruning) were tested for their capacity to enhance methane production from a food waste fermentate. In all biochar-supplemented (25 g/L) batch experiments, the complete methanogenic conversion of fermentate volatile fatty acids proceeded at a rate that was up to 5 times higher than that observed in the unamended (or sand-supplemented) controls. Fluorescent in situ hybridization analysis coupled with confocal laser scanning microscopy revealed an intimate association between archaea and bacteria around the biochar particles and provided a clear indication that biochar also shaped the composition of the microbial consortium. Based on the application of a suite of physico-chemical and electrochemical characterization techniques, we demonstrated that the positive effect of biochar is directly related to the electron-donating capacity (EDC) of the material, but is independent of its bulk electrical conductivity and specific surface area. The latter properties were all previously hypothesized to play a major role in the biochar-mediated interspecies electron transfer process in methanogenic consortia.
Collectively, these results of this study suggest that for biochar addition in anaerobic digester operation, the screening and identification of the most suitable biochar material should be based on EDC determination, via simple electrochemical tests.
We measure the far-infrared spectrum of N,N-Dimethyl-N-ethyl-N-benzylammonium (DEBA) bis(trifluoromethanesulfonyl)imide (TFSI) ionic liquid (IL) in the temperature range between 160 and 307 K. ...Differential scanning calorimetry measurements indicate that such IL undergoes a glass transition around 210 K. DFT calculations allow us to assign all the experimental absorptions to specific vibrations of the DEBA cation or of the two conformers of the TFSI anion. We find that the vibration frequencies calculated by means of the PBE0 functional are in better agreement with the experimental ones than those calculated at the B3LYP level, largely used for the attribution of vibration lines of ionic liquids. Experimentally we show that, in the liquid state, the relative concentrations of the two conformers of TFSI depend on temperature through the Boltzmann factor and the energy separation, ΔH, is found to be ≈2 kJ/mol, in agreement with previous calculations and literature. However, in the glassy state, the concentrations of the cis-TFSI and trans-TFSI remain fixed, witnessing the frozen state of this phase.
•Baricitinib, an anti-JAK1/JAK2, reduces cytokine release and SARS-Co-V2 entry.•In a retrospective multicenter study baricitinib reduces COVID-19 mortality rate.•Baricitinib reduces intensive care ...unit admissions of COVID-19 pneumonia.•Baricitinb reduces SARS-CoV-2 viral burden detected by nasopharyngeal swab.•Baricitinib used for 2 weeks was not associated with serious adverse events.
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The application of serological methods in HIV/AIDS routine surveillance systems to identify persons with recently acquired HIV infection has been proposed as a tool which may provide an accurate ...description of the current transmission patterns of HIV. Using the information about recent infection it is possible to estimate HIV incidence, according to the model proposed by Karon et al. in 2008, that accounts for the effect of testing practices on the number of persons detected as recently infected.
We used data from HIV/AIDS surveillance in the period 2004-2008 to identify newly diagnosed persons. These were classified with recent/non-recent infection on the basis of an avidity index result, or laboratory evidence of recently acquired infection (i.e., previous documented negative HIV test within 6 months; or presence of HIV RNA or p24 antigen with simultaneous negative/indeterminate HIV antibody test). Multiple imputation was used to impute missing information. The incidence estimate was obtained as the number of persons detected as recently infected divided by the estimated probability of detection. Estimates were stratified by calendar year, transmission category, gender and nationality.
During the period considered 3,633 new HIV diagnoses were reported to the regional surveillance system. Applying the model, we estimated that in 2004-2008 there were 5,465 new infections (95%CI: 4,538-6,461); stratifying by transmission category, the estimated number of infections was 2,599 among heterosexual contacts, 2,208 among men-who-have-sex-with-men, and 763 among injecting-drug-users. In 2008 there were 952 (625-1,229) new HIV infections (incidence of 19.9 per 100,000 person-years). In 2008, for men-who-have-sex-with-men (691 per 100,000 person-years) and injecting drug users (577 per 100,000 person-years) the incidence remained comparatively high with respect to the general population, although a decreasing pattern during 2004-2008 was observed for injecting-drug-users.
These estimates suggest that the transmission of HIV infection in Lazio remains frequent and men-who-have-sex-with men and injecting-drug-users are still greatly affected although the majority of new infections occurs among heterosexual individuals.
•QFT-Plus has similar sensitivity for active TB detection independently of HIV infection.•CD4 count does not influence IFNγ values of QFT-Plus in HIV-TB patients.•HIV-LTBI have high proportion of ...IFNγ values in the “uncertain range” of QFT-Plus.•Impairment of CD4 response to QFT-Plus antigens in the HIV-infected subjects.•Similar CD8 response to QFT-Plus antigens in HIV-infected and –uninfected subjects.
HIV-infection increases the risk to progress to active-tuberculosis (TB). Detection of latent TB infection (LTBI) is needed to eventually propose preventive-therapy and reduce TB reservoir. QuantiFERON-TB Plus (QFT-Plus)-test identifies LTBI. Currently, only two studies on QFT-Plus accuracy in HIV-infected-population are available in high TB-endemic-countries. Therefore we aimed to evaluate the effect of HIV-infection on QFT-Plus accuracy to detect LTBI in a low TB-endemic-country.
We enrolled 465 participants, among the 167 HIV-infected-persons: 32 with active-TB (HIV-TB), 45 remote-LTBI (HIV-LTBI) and 90 at low M. tuberculosis (Mtb)-infection risk. Among the 298 HIV-uninfected-persons: 170 with active-TB, 76 recent-LTBI, 34 remote-LTBI and 18 with low Mtb-infection risk.
QFT-Plus sensitivity was similar in TB regardless of HIV-status. CD4-count did not influence the distribution of IFN-γ values in HIV-TB and HIV-LTBI. Moreover HIV-LTBI and HIV-uninfected remote LTBI had a similar proportion of results in the uncertain range (IFNγ ≥0.2 ≤ 0.7 IU/ml) differently from those LTBI-persons reporting recent-exposure (p = 0.016). Cytometry results demonstrated that CD8-response was similar in HIV-infected- and -uninfected-persons whereas CD4-response was impaired in HIV-infected-persons (p = 0.011).
HIV-infection does not affect QFT-Plus response in active-TB, whereas the time of exposure influences the proportion of uncertain-results in LTBI.
Summary Objective The aim of this study was to determine the occurrence of polymorphic variants of EBV Bam HI fragment Z (BZLF1) promoter zone Zp in tumor and non-tumor-associated EBV. We ...characterized the Zp region in type A and type B EBV, infecting AIDS-related non-Hodgkin's lymphomas (AIDS-NHL) and non-malignant lymphoid tissues derived from HIV-positive patients and from healthy individuals. Methods The Zp region was directly sequenced in 133 EBV-positive DNA samples: 63 AIDS-NHL (32 systemic AIDS-NHL and 31 AIDS-primary central nervous system lymphoma AIDS-PCNSL), 30 lymphoid tissues derived from HIV-positive individuals and 40 lymphoid samples derived from healthy individuals. The chi square test was used to assess for statistically significant differences among proportions, and a two-tailed P value ≤0.05 was chosen as statistically significant. Results We found three polymorphic Zp variants: Zp-P, considered to be the prototype sequence; Zp-V3, that differs from Zp-P for three nucleotide substitutions; and a new variant, Zp-PV, that differs from Zp-P for a single nucleotide substitution. Zp-V3 was significantly associated with AIDS-PCNSL ( P < 0.001) and with systemic AIDS-NHL ( P = 0.007), in particular with AIDS-related immunoblastic lymphoma ( P < 0.001). Moreover, in malignant samples, this variant was also significantly associated with type B EBV ( P < 0.001). Finally, the new identified Zp-PV variant was isolated in 7 AIDS-PCNSL. Conclusions The frequency of polymorphisms in the regulatory zone of BZLF1 is different between malignant and non-malignant samples in AIDS patients and may identify EBV subtypes with different transforming activities, including those associated to the pathogenesis of B cell lymphoma.
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