Pulsed electrolysis - explained.

Lately, there has been high interest in electrolysis under dynamic conditions, the so-called pulsed electrolysis. Different studies have shown that in pulsed electrolysis, selectivity towards certain products can be improved compared to steady-state operation. Many groups also demonstrated that the selectivity can be tuned by selection of pulsing profile, potential limits, as well as frequency of the change. To explain the origin of this improvement, some modeling studies have been performed. However, it seems that a theoretical framework to study this effect is still missing. In the present contribution, we suggest a theoretical framework of nonlinear frequency response analysis for the evaluation of the process improvement under pulsed electrolysis conditions. Of special interest is the DC component, which determines how much the mean output value under dynamic conditions will be different from the value under steady-state conditions. Therefore, the DC component can be considered as a measure of process improvement under dynamic conditions compared to the steady-state operation. We show that the DC component is directly dependent on nonlinearities of the electrochemical process and demonstrate how this DC component can be calculated theoretically as well as how it can be obtained from measurements.

A fast magnetic vector characterization method for quasi two-dimensional systems and heterostructures.

The use of magnetic vector tomography/laminography has opened a 3D experimental window to access the magnetization at the nanoscale. These methods exploit the dependence of the magnetic contrast in transmission to recover its 3D configuration. However, hundreds of different angular projections are required leading to large measurement times. Here we present a fast method to dramatically reduce the experiment time specific for quasi two-dimensional magnetic systems. The algorithm uses the Beer-Lambert equation in the framework of X-ray transmission microscopy to obtain the 3D magnetic configuration of the sample. It has been demonstrated in permalloy microstructures, reconstructing the magnetization vector field with a reduced number of angular projections obtaining quantitative results. The throughput of the methodology is × 10-× 100 times faster than conventional magnetic vector tomography, making this characterization method of general interest for the community.

Glycerol amendment enhances biosulfidogenesis in acid mine drainage-affected areas: An incubation column experiment.

Microbial sulfate (SO4 2-) reduction in Acid Mine Drainage (AMD) environments can ameliorate the acidity and extreme metal concentrations by consumption of protons via the reduction of SO4 2- to hydrogen sulfide (H2S) and the concomitant precipitation of metals as metal sulfides. The activity of sulfate-reducing bacteria can be stimulated by the amendment of suitable organic carbon sources in these generally oligotrophic environments. Here, we used incubation columns (IC) as model systems to investigate the effect of glycerol amendment on the microbial community composition and its effect on the geochemistry of sediment and waters in AMD environments. The ICs were built with natural water and sediments from four distinct AMD-affected sites with different nutrient regimes: the oligotrophic Filón Centro and Guadiana acidic pit lakes, the Tintillo river (Huelva, Spain) and the eutrophic Brunita pit lake (Murcia, Spain). Physicochemical parameters were monitored during 18 months, and the microbial community composition was determined at the end of incubation through 16S rRNA gene amplicon sequencing. SEM-EDX analysis of sediments and suspended particulate matter was performed to investigate the microbially-induced mineral (neo)formation. Glycerol amendment strongly triggered biosulfidogenesis in all ICs, with pH increase and metal sulfide formation, but the effect was much more pronounced in the ICs from oligotrophic systems. Analysis of the microbial community composition at the end of the incubations showed that the SRB Desulfosporosinus was among the dominant taxa observed in all sulfidogenic columns, whereas the SRB Desulfurispora, Desulfovibrio and Acididesulfobacillus appeared to be more site-specific. Formation of Fe3+ and Al3+ (oxy)hydroxysulfates was observed during the initial phase of incubation together with increasing pH while formation of metal sulfides (predominantly, Zn, Fe and Cu sulfides) was observed after 1-5 months of incubation. Chemical analysis of the aqueous phase at the end of incubation showed almost complete removal of dissolved metals (Cu, Zn, Cd) in the amended ICs, while Fe and SO4 2- increased towards the water-sediment interface, likely as a result of the reductive dissolution of Fe(III) minerals enhanced by Fe-reducing bacteria. The combined geochemical and microbiological analyses further establish the link between biosulfidogenesis and natural attenuation through metal sulfide formation and proton consumption.

Revealing 3D magnetization of thin films with soft X-ray tomography: magnetic singularities and topological charges.

The knowledge of how magnetization looks inside a ferromagnet is often hindered by the limitations of the available experimental methods which are sensitive only to the surface regions or limited in spatial resolution. Here we report a vector tomographic reconstruction based on soft X-ray transmission microscopy and magnetic dichroism data, which has allowed visualizing the three-dimensional magnetization in a ferromagnetic thin film heterostructure. Different non-trivial topological textures have been resolved and the determination of their topological charge has allowed us to identify a Bloch point and a meron-like texture. Our method relies only on experimental data and might be of wide application and interest in 3D nanomagnetism.

The chaperonin CCT controls T cell receptor-driven 3D configuration of centrioles.

T lymphocyte activation requires the formation of immune synapses (IS) with antigen-presenting cells. The dynamics of membrane receptors, signaling scaffolds, microfilaments, and microtubules at the IS determine the potency of T cell activation and subsequent immune response. Here, we show that the cytosolic chaperonin CCT (chaperonin-containing TCP1) controls the changes in reciprocal orientation of the centrioles and polarization of the tubulin dynamics induced by T cell receptor in T lymphocytes forming an IS. CCT also controls the mitochondrial ultrastructure and the metabolic status of T cells, regulating the de novo synthesis of tubulin as well as posttranslational modifications (poly-glutamylation, acetylation, Δ1 and Δ2) of αß-tubulin heterodimers, fine-tuning tubulin dynamics. These changes ultimately determine the function and organization of the centrioles, as shown by three-dimensional reconstruction of resting and stimulated primary T cells using cryo-soft x-ray tomography. Through this mechanism, CCT governs T cell activation and polarity.

[Clinical characteristics of patients with stroke code activation not identified by the emergency medical service]. / Características clínicas de los pacientes con activación de código ictus no identificados por el servicio de emergencias médicas.

AIMS: To determine the sensitivity of stroke detection by emergency medical services (EMS) and to analyse the clinical characteristics of unidentified patients with suspected stroke. PATIENTS AND METHODS: Prospective register of patients with suspected stroke in our area (850,000 inhabitants) from 2011 to 2017. The population that notified the EMS was selected. Of this population, patients with and without stroke code activation by the EMS were compared (EMS+ versus EMS-). Demographics, time to progression, clinical characteristics of the episode and reperfusion therapy administered were recorded. RESULTS: Of a total of 5,497 patients with suspected stroke, 2,087 alerted the EMS: 1,611 (77%) EMS+ and 476 (33%) EMS-. The EMS- patients presented lower scores on the National Institute of Health Stroke Scale (8 vs. 11) and a greater frequency of clinical features of the vertebrobasilar territory (14.1% vs. 8.7%) and partial hemispheric clinical features (23.5% vs. 18.4%), especially in the left hemisphere (78.1% vs. 48.4%). Reperfusion treatment was administered in 29% of EMS+ and 23% of EMS-. The time from symptom onset to treatment was 42 minutes longer in the EMS group (175 versus 133 minutes). CONCLUSIONS: The sensitivity of EMS to detect stroke patients in our series is 77%. We have identified clinical features associated with lack of sensitivity, such as vertebrobasilar territory symptoms or isolated language disorder.

TITLE: Características clínicas de los pacientes con activación de código ictus no identificados por el servicio de emergencias médicas.Objetivos. Determinar la sensibilidad de detección de ictus por parte de los servicios de emergencias médicas (SEM) y analizar las características clínicas de los pacientes con sospecha de ictus no identificados. Pacientes y métodos. Registro prospectivo de pacientes con sospecha de ictus de nuestra área (850.000 habitantes) desde 2011 hasta 2017. Se seleccionó a la población que avisó al SEM. De ésta, se compararon los pacientes con y sin activación de código ictus por parte del SEM (SEM+ frente a SEM-). Se registraron los datos demográficos, el tiempo de evolución, las características clínicas del episodio y el tratamiento de reperfusión administrado. Resultados. De un total de 5.497 pacientes con sospecha de ictus, 2.087 alertaron al SEM: 1.611 (77%) SEM+ y 476 (33%) SEM-. Los pacientes SEM- presentaron menor puntuación en la National Institute of Health Stroke Scale (8 frente a 11) y mayor frecuencia de clínica de territorio vertebrobasilar (14,1% frente a 8,7%) y de clínica hemisférica parcial (23,5% frente a 18,4%), especialmente del hemisferio izquierdo (78,1% frente a 48,4%). Se administró tratamiento de reperfusión en el 29% de los SEM+ y en el 23% de los SEM-. El tiempo desde el inicio de los síntomas hasta el tratamiento fue 42 minutos más largo en el grupo de pacientes SEM- (175 frente a 133 minutos). Conclusiones. La sensibilidad del SEM para detectar pacientes con ictus en nuestra serie es del 77%. Hemos identificado características clínicas asociadas a la falta de sensibilidad, como los síntomas de territorio vertebrobasilar o el trastorno de lenguaje aislado.

Characterization of sustainable polyhydroxyls, produced from bio-based feedstock, and polyurethane and copolymer urethane-amide foams.

This manuscript presents data related to the research article entitled "Synthesis and characterization of sustainable polyurethane foams based on polyhydroxyls with different terminal groups" (DOI: 10.1016/j.polymer.2018.06.077) [1]. We provide Supplementary data on the chemical properties, in terms of FTIR characterization, of polyhydroxyls produced starting from bio-based feedstock (biosuccinic acid and 1,4 butandiol) and thermal properties (glass transition temperature-Tg and thermal degradation behavior) of polyurethane and copolymer urethane-amide foams manufactured from the aforementioned polyhydroxyls. The FTIR characterization elucidates the chemical structure of polyhydroxyls and allows to make some hypothesis on their reaction routes with the isocyanate molecules. The thermal characterization revealed that the addition of bio-based polyhydroxyls to the sample formulations improves both the glass transition and degradation temperature of the foams. These foamed products exhibit potential performances to be applied as a substitute for conventional polyurethane foams.

Human PRDM2: Structure, function and pathophysiology.

PRDM2/RIZ is a member of a superfamily of histone/protein methyltransferases (PRDMs), which are characterized by the conserved N-terminal PR domain, with methyltransferase activity and zinc finger arrays at the C-terminus. Similar to other family members, two main protein types, known as RIZ1 and RIZ2, are produced from the PRDM2 locus differing by the presence or absence of the PR domain. The imbalance in their respective amounts may be an important cause of malignancy, with the PR-positive isoform commonly lost or downregulated and the PR-negative isoform always being present at higher levels in cancer cells. Interestingly, the RIZ1 isoform also represents an important target of estradiol action downstream of the interaction with hormone receptor. Furthermore, the imbalance between the two products could also be a molecular basis for other human diseases. Thus, understanding the molecular mechanisms underlying PRDM2 function could be useful in the pathophysiological context, with a potential to exploit this information in clinical practice.

Differences between graphene and graphene oxide in gelatin based systems for transient biodegradable energy storage applications.

A comparison between graphene flakes and graphene oxide as filler in gelatin based systems for low-cost transient biodegradable energy storage applications has been carried out. The two bio-composites have been prepared and characterized by rheological measurements, cyclic voltammetry measurements, chronopotentiometry measurements and impedance spectroscopy. Differences in dielectric and mechanical properties have been correlated to the different structural organizations determinate by the hydrophobic/hydrophilic character of the used filler. In particular, the addition of the graphene oxide to the gelatin causes an increase in the elastic modulus with a parallel increase in the mechanical stability with time as compared to the composites obtained by adding graphene. Conversely, the surface capacitance is slightly increased by the graphene oxide addition compared to the pure gelatin sample. On the other hand, the introduction of the graphene flakes into the gelatin leads to a marked increase of the dielectric properties of the resulting bio-composite.

Light irradiation tuning of surface wettability, optical, and electric properties of graphene oxide thin films.

In this work the preparation of flexible polymeric films with controlled electrical conductivity, light transmission and surface wettability is reported. A drop casted graphene oxide thin film is photo-reduced at different levels by UV light or laser irradiation. Optical microscopy, IR spectroscopy, electrical characterization, Raman spectroscopy and static water contact angle measurements are used in order to characterize the effects of the various reduction methods. Correlations between the optical, electrical and structural properties are reported and compared to previous literature results. These correlations provide a useful tool for independently tuning the properties of these films for specific applications.

Optical pseudomotors for soft x-ray beamlines.

Optical elements of soft x-ray beamlines usually have motorized translations and rotations that allow for the fine alignment of the beamline. This is to steer the photon beam at some positions and to correct the focus on slits or on sample. Generally, each degree of freedom of a mirror induces a change of several parameters of the beam. Inversely, several motions are required to actuate on a single optical parameter, keeping the others unchanged. We define optical pseudomotors as combinations of physical motions of the optical elements of a beamline, which allow modifying one optical parameter without affecting the others. We describe a method to obtain analytic relationships between physical motions of mirrors and the corresponding variations of the beam parameters. This method has been implemented and tested at two beamlines at ALBA, where it is used to control the focus of the photon beam and its position independently.

Nanoscale imaging of buried topological defects with quantitative X-ray magnetic microscopy.

Advances in nanoscale magnetism increasingly require characterization tools providing detailed descriptions of magnetic configurations. Magnetic transmission X-ray microscopy produces element specific magnetic domain images with nanometric lateral resolution in films up to ∼100 nm thick. Here we present an imaging method using the angular dependence of magnetic contrast in a series of high resolution transmission X-ray microscopy images to obtain quantitative descriptions of the magnetization (canting angles relative to surface normal and sense). This method is applied to 55-120 nm thick ferromagnetic NdCo5 layers (canting angles between 65° and 22°), and to a NdCo5 film covered with permalloy. Interestingly, permalloy induces a 43° rotation of Co magnetization towards surface normal. Our method allows identifying complex topological defects (merons or ½ skyrmions) in a NdCo5 film that are only partially replicated by the permalloy overlayer. These results open possibilities for the characterization of deeply buried magnetic topological defects, nanostructures and devices.

Characterization of the polycaprolactone melt crystallization: complementary optical microscopy, DSC, and AFM studies.

The first stages of the crystallization of polycaprolactone (PCL) were studied using several techniques. The crystallization exotherms measured by differential scanning calorimetry (DSC) were analyzed and compared with results obtained by polarized optical microscopy (POM), rheology, and atomic force microscope (AFM). The experimental results suggest a strong influence of the observation scale. In particular, the AFM, even if limited on time scale, appears to be the most sensitive technique to detect the first stages of crystallization. On the contrary, at least in the case analysed in this work, rheology appears to be the least sensitive technique. DSC and POM provide closer results. This suggests that the definition of induction time in the polymer crystallization is a vague concept that, in any case, requires the definition of the technique used for its characterization.

Transglutaminase-mediated macromolecular assembly: production of conjugates for food and pharmaceutical applications.

Various strategies have been explored in the last 20 years to modify the functional properties of proteins and, among these, protein/polymer conjugation resulted one of the most successful approaches. Thus, the surface modification of polypeptides of potential industrial interest by covalent attachment of different macromolecules is nowadays regarded as an extremely valuable technique to manipulate protein activities. Protein derivatives with a number of either natural or synthetic polymers, like different polysaccharides or polyethylene glycol, have been obtained by both chemical and enzymatic treatments, and in this context, the crosslinking enzyme transglutaminase is attracting an increasing attention as a simple and safe means for protein processing in vitro. In this short review, we summarized the most significant experimental findings demonstrating that a microbial form of the enzyme is an effective tool to obtain several biopolymer-based conjugates potentially useful for both food and pharmaceutical applications.

Volatile compounds and bacterial community dynamics of chestnut-flour-based sourdoughs.

The aims of this study were the monitoring of the microbial dynamics by means of a polyphasic approach based on conventional isolation techniques and PCR-DGGE-based methods in different chestnut-based sourdoughs and the evaluation of the impact of fermentation on volatile organic compounds formation during sourdoughs ripening. Members of the Lactobacillus plantarum group and Pediococcus pentosaceous dominated the sourdough ecosystems. Nevertheless, RAPD-PCR allowed recording a relevant genotypic biodiversity among strains coming from gluten-free flour combinations. Volatile compounds were characterised by GC/MS. A total of 59 volatile compounds were identified, mainly alcohols, esters, acids, aldehydes and ketones. Principal component analysis of samples at the beginning and at the end of ripening offered a good separation of the samples and highlighted the effect of fermentation on the sensorial profile.

FK506 binding protein 51 positively regulates melanoma stemness and metastatic potential.

Melanoma is the most aggressive skin cancer; there is no cure in advanced stages. Identifying molecular participants in melanoma progression may provide useful diagnostic and therapeutic tools. FK506 binding protein 51 (FKBP51), an immunophilin with a relevant role in developmental stages, is highly expressed in melanoma and correlates with aggressiveness and therapy resistance. We hypothesized a role for FKBP51 in melanoma invasive behaviour. FKBP51 promoted activation of epithelial-to-mesenchymal transition (EMT) genes and improved melanoma cell migration and invasion. In addition, FKBP51 induced some melanoma stem cell (MCSC) genes. Purified MCSCs expressed high EMT genes levels, suggesting that genetic programs of EMT and MCSCs overlap. Immunohistochemistry of samples from patients showed intense FKBP51 nuclear signal and cytoplasmic positivity for the stem cell marker nestin in extravasating melanoma cells and metastatic brains. In addition, FKBP51 targeting by small interfering RNA (siRNA) prevented the massive metastatic substitution of liver and lung in a mouse model of experimental metastasis. The present study provides evidence that the genetic programs of cancer stemness and invasiveness overlap in melanoma, and that FKBP51 plays a pivotal role in sustaining such a program.

Quantification of cytomegalovirus DNA by a fully automated real-time PCR for early diagnosis and monitoring of active viral infection in solid organ transplant recipients.

BACKGROUND: Quantification of cytomegalovirus (CMV) DNA by real-time PCR is currently considered an alternative diagnostic approach for the evaluation of active infection in transplant patients. The pp65 antigenemia assay has been used as reference test for monitoring active CMV infection and guiding preemptive therapy in transplant recipients. However, this assay suffers from some limitations: need for immediate processing of the samples, labour-intensive process, lack of standardization and subjective result interpretation. OBJECTIVES: The aim of this study was to evaluate the performance of a new commercially available real-time PCR assay coupled with a fully automated DNA extraction system (COBAS Ampliprep/COBAS Taqman CMV Test, Roche Diagnostics) for the detection of CMV-DNA in plasma comparing it with pp65 antigenemia assay for monitoring active CMV infection in solid organ transplant recipients (SOTRs). STUDY DESIGN: A total of 266 consecutive samples from 45 SOTRs were monitored with pp65 antigenemia and in parallel with CMV-DNA quantitation by real-time PCR assay. RESULTS: Fifty-eight samples resulted PCR-positive, 163 negative and for 45 samples the CMV-DNA values obtained were below the lower limit of quantification (<150 copies/ml); pp65 antigen was detected in 47 samples and resulted negative in 219 specimens. Concordance between the two evaluations was 76.7%; also a good correlation was observed (r=0.718). Considering the existing treatment criteria based on pp65 antigenemia evaluation corresponding to pp65 levels≥20 positive cells/200,000, preemptive therapy was administered to four asymptomatically infected patients. The corresponding cut-off value of CMV-DNA load calculated for discrimination between self-clearing infections and those requiring therapy was 2500 copies/ml (or 2275 IU/ml). CONCLUSION: The fully automated real-time PCR from Roche provided specific and sensitive results and represented a rapid and simple assay for the evaluation and monitoring of CMV infection in SOTRs. Further studies are required to validate the threshold level for the initiation of preemptive therapy.

Performance of different commercial methods for determining minimum inhibitory concentrations of glycopeptides and linezolid against blood isolates of Staphylococcus aureus.

The aim of this study was to determine the accuracy of commercial systems (VITEK® 2, Etest and Sensititre®) in determining the minimum inhibitory concentrations of vancomycin, teicoplanin and linezolid of Staphylococcus aureus strains and to evaluate the reproducibility of each system in a clinical microbiology laboratory. In total, 115 strains of S. aureus isolated from blood cultures were tested with all three commercial methods as well as the broth microdilution method, which is designated as the standard for glycopeptides and linezolid. Fourteen different S. aureus strains were included in a reproducibility test for all methods and antibiotics. For these strains, antimicrobial susceptibility testing was repeated 10 times on different days with all four methods, each time using the same inoculum. All three commercial methods exhibited similar performance in categorisation of nearly all of the meticillin-susceptible S. aureus (MSSA) isolates. Discrepancies were registered for meticillin-resistant S. aureus (MRSA); 2.5% of the strains in the intermediate or resistant category with the VITEK 2 system were not recognised as resistant by Etest and Sensititre. Moreover, none of the three commercial methods provided accurate results compared with homemade broth microdilution. Reproducibility of vancomycin and teicoplanin was 100% with VITEK 2 and Sensititre and 98.75% with Etest. Microdilution showed a reproducibility of 95.6% with vancomycin and 83.1% with teicoplanin. In contrast to previous reports, the best agreement with microdilution was exhibited by VITEK 2 both for MSSA and MRSA. For the antibiotics tested, the best reproducibility was obtained with the VITEK 2 and Sensititre systems.

Iterative retrieval of one-dimensional x ray wave field using a single intensity measurement.

The problem of retrieving a complex function from the modulus of its Fourier transform has non-unique solutions in one dimension. Therefore iterative phase retrieval methods cannot in general be confidently applied to one-dimensional problems, due to the presence of ambiguities. We present a method for a posteriori reduction of the ambiguities based on the correlation analysis of the solution of a large number of runs of an iterative phase retrieval algorithm with different random starting phases. The method is applied to experimentally measured diffraction patterns from an x ray waveguide illuminated by hard x rays. We demonstrate the possibility of retrieving the complex wave field at the exit face of the waveguide and compare the result with theoretical prediction.

Characterization of volatile fraction of typical Irpinian wines fermented with a new starter yeast.

Non-Saccharomyces yeasts are microorganisms that play an important role in the fermentation dynamics, compositions and flavour of wine. The aromatic compounds responsible for varietal aroma in wine are mainly terpenes, of which the most important group are the monoterpenes because of their volatility and odour if present in a free form. In fact, some terpenyl-glycosides do not contribute to the aroma unless they are hydrolysed. The glycosylated form of terpenes can be converted by hydrolysis with ß-glycosidases produced by yeasts during the winemaking process, into aromatic compounds. In this study we utilized a non-Saccharomyces yeast, with a high extra-cellular glycosidase activity, isolated from grapes of cultivars typical of Irpinia region. This strain, identified as a Rhodotorula mucillaginosa (strain WLR12), was used to carry out an experimental winemaking process and the results were compared with those obtained with a commercial yeast starter. Chemical and sensorial analysis demonstrated that the wines produced with WLR12 strain had a more floral aroma and some sweet and ripened fruit notes compared to those obtained with commercial yeast. The data also showed an increasing of the free terpenes fraction that, however, did not significatively modify the bouquet of the wines.