Synthesis of phosphatidylcholine and phosphatidylethanolamine at different ages in the rat brain in vitro

The de novo synthesis of choline and ethanolamine phosphoglycerides in brain microsomes from 18 month-old male rats was investigated in vitro by using labeled cytidine-5′-diphosphate choline and cytidine-5′-diphosphate ethanolamine as lipid precursors. The rate of synthesis of the two phospholipid classes was found to be noticeably decreased, as compared to that of adult animals. The addition of exogenous diacyl glycerols to microsomes from ageing rat brain brings the rate of synthesis nearly to the adult levels. The synthesis of choline and ethanolamine phosphoglycerides is not affected in the liver microsomes of ageing rats. The molar distribution of fatty acids in brain microsomal diacyl glycerols of ageing rats is noticeably different from that of adult animals. The content of monoenoic and dienoic species is increased, whereas that of the tetraenoic species is decreased. Base exchange reaction for choline and ethanolamine incorporation into respective phospholipids is not affected in the brain microsomes of the aged rats.     

The Influence of Fe Content on the Mechanical Properties of NiAl Coatings Processed In-Situ

NiAl Plasma Transferred Arc coatings can be processed by in-situ synthesis of the aluminide during the deposition of mixtures of Ni and Al powders. This procedure allows to deposit compositions that otherwise would exhibit low weldability. The strong metallurgical bond of coatings involves the formation of a weld pool. It is therefore expected for the composition of the processed coatings to be influenced both by the deposited and base material, besides processing parameters. This study analyzed the impact of the deposition current on the point defect structure in the B2NiAl-ordered structure and consequently on the coating hardness and indentation modulus. Mixtures of 65 at.%Ni and 35 at.%Al were prepared and deposited on carbon steel and stainless steel plates. Deposition current ranging from 70 to 150 A was used to induce different Fe content in the coatings. Results showed that increasing deposition current increased dilution with substrate but contrary to observations on metallic coatings, an increase of hardness and indentation modulus was measured. The hypothesis that the measured behavior is related to the point defect structure of the ordered phase, B2-NiAl, is put forward. The Fe content determined the density and type of point defects: vacancies, anti-sites Al or Ni. A better understanding on the mechanisms controlling the properties of the aluminide PTA coatings with increasing deposition current is achieved: hardness exhibiting a direct correlation with the point defect structure and the indentation modulus a strong dependence on the microstructure.     

Relationship between local and global modulus of elasticity in bending and its consequence on structural timber grading

The study analyses the relationship between local and global modulus of elasticity and develops and evaluates different models to predict local from global modulus measurements. The mechanical tests were performed on four species commonly used in Italy for structural purposes: fir, Douglas-fir, Corsican pine and chestnut. Two or three cross-sections and two provenances were sampled for each species. A theoretical analysis showed that the local–global modulus relationship was of polynomial form with only one coefficient. The effect of the species on the relationship was significant as well as the cross-section but only for softwoods. The effect of the cross-section was explained by the presence and the size of defects in the mid span. The different models were applied and then compared by means of the optimum grading: only slight differences among models emerged. Although optimum grading was strongly dependent on the sampling and on the grade combination, for softwoods the model for species and section showed very similar results to the grading with the true local modulus; inclusion of the knot values in the model led to only slight improvements. For chestnut all models were found to be comparable.     

Upgrading of a syngas mixture for pure hydrogen production in a Pd-Ag membrane reactor

Water gas shift (WGS) is a thermodynamics limited reaction and CO equilibrium conversion of a traditional reactor is furthermore reduced owing to the presence of H₂ (ca. 50%) in the feed stream coming from a reformer.The upgrading of a simulated reformate stream was experimentally investigated as a function of temperature (280-320 °C), feed pressure (up to 600 kPa), gas hourly space velocity (GHSV), etc. using a Pd-alloy membrane reactor (MR) packed with a commercial catalyst CuO/CeO₂/Al₂O₃; no sweep gas was used. The MR performance was also evaluated using new parameters such as conversion index, H₂ recovery and extraction index, etc., which evidence the advantages with respect to a traditional reactor.A Pd-based MR operated successfully overcoming the thermodynamic constraints of a traditional reactor and, specifically, the drawback introduced by the hydrogen presence. In fact, a CO conversion of 90% significantly exceeded (three times) the thermodynamics upper limit (<36%) of a traditional reactor owing to ca. 80% of hydrogen permeated through the membrane.The overall process performance was significantly improved by the presence of the Pd-based membrane and, thus, by the high reaction pressure which allowed and drove the hydrogen permeation.     

Molecular and quantitative analysis of metal ion binding to humic acids from sewage sludge and sludge-amended soils by fluorescence spectroscopy

Humic acids (HAs) isolated from sewage sludge (SS) and control and SS-amended soils were characterized by fluorescence spectroscopy. The main feature of fluorescence spectra was a broad band with the maximum centered at excitation/emission wavelengths that were much shorter for SS-HA (340/438 nm) than for any soil HA (440/510 nm). Titration with Cu(II), Zn(II), Cd(II), and Pb(II) ions decreased fluorescence intensities of HAs. Titration data were fitted to a single-site fluorescence quenching model, and metal ion complexing capacities of each HA sample and stability constants of metal ion-HA complexes were calculated. The binding capacities of HAs and strengths of metal ion-HA complexes followed the order Pb(II) > Cu(II) > Cd(II) > Zn(II). With respect to the control soil HA, SS-HA, which showed the smallest contents of acidic functional groups and the lowest humification degree, was characterized by much smaller binding capacities and stability constants. The binding capacities and affinities of SS-amended soil HA were intermediate between those of native soil HA and SS-HA but closer to the former, thus suggesting a partial incorporation of HA fractions of SS into native soil HAs. These effects are expected to have a great impact on the behavior of metals in SS-amended soils.     

Evidence for Biological Age Acceleration and Telomere Shortening in COVID-19 Survivors

The SARS-CoV-2 infection determines the COVID-19 syndrome characterized, in the worst cases, by severe respiratory distress, pulmonary and cardiac fibrosis, inflammatory cytokine release, and immunosuppression. This condition has led to the death of about 2.15% of the total infected world population so far. Among survivors, the presence of the so-called persistent post-COVID-19 syndrome (PPCS) is a common finding. In COVID-19 survivors, PPCS presents one or more symptoms: fatigue, dyspnea, memory loss, sleep disorders, and difficulty concentrating. In this study, a cohort of 117 COVID-19 survivors (post-COVID-19) and 144 non-infected volunteers (COVID-19-free) was analyzed using pyrosequencing of defined CpG islands previously identified as suitable for biological age determination. The results show a consistent biological age increase in the post-COVID-19 population, determining a DeltaAge acceleration of 10.45 ± 7.29 years (+5.25 years above the range of normality) compared with 3.68 ± 8.17 years for the COVID-19-free population (p < 0.0001). A significant telomere shortening parallels this finding in the post-COVID-19 cohort compared with COVID-19-free subjects (p < 0.0001). Additionally, ACE2 expression was decreased in post-COVID-19 patients, compared with the COVID-19-free population, while DPP-4 did not change. In light of these observations, we hypothesize that some epigenetic alterations are associated with the post-COVID-19 condition, particularly in younger patients (< 60 years).     

Realization and Preliminary Measurements on a 94 GHz SIS Mixer

In this paper we present the realization and a preliminary characterization of a SIS based receiver. It has been developed for the MASTER experiment that consists in a three-band SIS receiver (94, 225 and 345 GHz) for astrophysical observations through the atmospheric windows available at high altitude dry sites. The measurements performed establish an upper limit to the overall receiver noise temperature. A comparison has been tried with the MASTER requirements and with state of the art results. A noise figure of 110 K has been obtained at 94 GHz, about 22 times the quantum limit.     

Transforming paper documents into XML format with WISDOM++

The transformation of scanned paper documents to a form suitable for an Internet browser is a complex process that requires solutions to several problems. The application of an OCR to some parts of the document image is only one of the problems. In fact, the generation of documents in HTML format is easier when the layout structure of a page has been extracted by means of a document analysis process. The adoption of an XML format is even better, since it can facilitate the retrieval of documents in the Web. Nevertheless, an effective transformation of paper documents into this format requires further processing steps, namely document image classification and understanding. WISDOM++ is a document processing system that operates in five steps: document analysis, document classification, document understanding, text recognition with an OCR, and transformation into HTML/XML format. The innovative aspects described in the paper are: the preprocessing algorithm, the adaptive page segmentation, the acquisition of block classification rules using techniques from machine learning, the layout analysis based on general layout principles, and a method that uses document layout information for conversion to HTML/XML formats. A benchmarking of the system components implementing these innovative aspects is reported. Received June 15, 2000 / Revised November 7, 2000