Interaction of a Long Alkyl Chain Protic Ionic Liquid and Water

A combined experimental/theoretical approach has been used to investigate the role of water in modifying the microscopic interactions characterizing the optical response of butyl-ammonium nitrate (BAN) water solutions. Raman spectra, dominated by the signal from the protic ionic liquid, were collected as a function of the water content, and the corresponding spatial organization of the ionic couples, as well as their local arrangement with water molecules, was studied exploiting classical molecular dynamics calculations. High quality spectroscopic data, combined with a careful analysis, revealed that water affects the vibrational spectrum BAN in solution: as the water concentration is increased, peaks assigned to stretching modes show a frequency hardening together with a shape narrowing, whereas the opposite behavior is observed for peaks assigned to bending modes. Calculation results clearly show a nanometric spatial organization of the ionic couples that is not destroyed on increasing the water content at least within an intermediate range. Our combined results show indeed that small water concentrations even increase the local order. Water molecules are located among ionic couples and are closer to the anion than the cation, as confirmed by the computation of the number of H-bonds which is greater for water-anion than for water-cation. The whole results set thus clarifies the microscopic scenario of the BAN-water interaction and underlines the main role of the extended hydrogen bond network among water molecules and nitrate anions.Comment: 27 pages, 10 figure

High-pressure behavior of methylammonium lead iodide (MAPbI3) hybrid perovskite

In this paper we provide an accurate high-pressure structural and optical study of MAPbI3 hybrid perovskite. Structural data show the presence of a phase transition towards an orthorhombic structure around 0.3 GPa followed by full amorphization of the system above 3 GPa. After releasing pressure the systems keeps the high-pressure orthorhombic phase. The occurrence of these structural transitions is further confirmed by pressure induced variations of the photoluminescence signal at high pressure. These variations clearly indicate that the bandgap value and the electronic structure of MAPI change across the phase transition.Comment: 23 pages, 9 figure

An Optimization-enhanced MANO for Energy-efficient 5G Networks

5G network nodes, fronthaul and backhaul alike, will have both forwarding and computational capabilities. This makes energy-efficient network management more challenging, as decisions such as activating or deactivating a node impact on both the ability of the network to route traffic and the amount of processing it can perform. To this end, we formulate an optimization problem accounting for the main features of 5G nodes and the traffic they serve, allowing joint decisions about (i) the nodes to activate, (ii) the network functions they run, and (iii) the traffic routing. Our optimization module is integrated within the management and orchestration framework of 5G, thus enabling swift and high-quality decisions. We test our scheme with both a real-world testbed based on OpenStack and OpenDaylight, and a large-scale emulated network whose topology and traffic come from a real-world mobile operator, finding it to consistently outperform state-of-the art alternatives and closely match the optimum

Assembling patchy plasmonic nanoparticles with aggregation-dependent antibacterial activity

We realise an antibacterial nanomaterial based on the self-limited assembly of patchy plasmonic colloids, obtained by adsorption of lysozyme to gold nanoparticles. The possibility of selecting the size of the assemblies within several hundred nanometres allows for tuning their optical response in a wide range of frequencies from visible to near infrared. We also demonstrate an aggregation-dependent modulation of the catalytic activity, which results in an enhancement of the antibacterial performances for assemblies of the proper size. The gained overall control on structure, optical properties and biological activity of such nanomaterial paves the way for the development of novel antibacterial nanozymes with promising applications in treating multi drug resistant bacteria

The critical structural role of a highly conserved histidine residue in group II amino acid decarboxylases

AbstractGlutamate decarboxylase is a pyridoxal 5′-phosphate (PLP)-dependent enzyme, belonging to the subset of PLP-dependent decarboxylases classified as group II. Site-directed mutagenesis of Escherichia coli glutamate decarboxylase, combined with analysis of the crystal structure, shows that a histidine residue buried in the protein core is critical for correct folding. This histidine is strictly conserved in the PF00282 PFAM family, which includes the group II decarboxylases. A similar role is proposed for residue Ser269, also highly conserved in this group of enzymes, as it provides one of the interactions stabilising His241

Intracellular heavy metal nanoparticle storage: progressive accumulation within lymph nodes with transformation from chronic inflammation to malignancy

A 25-year-old man had complained of sudden fever spikes for two years and his blood tests were within the normal range. In 1993, a surgical biopsy of swollen left inguinal lymph nodes was negative for malignancy, but showed reactive lymphadenitis and widespread sinus histiocytosis. A concomitant needle biopsy of the periaortic lymph nodes and a bone marrow aspirate were also negative. In 1994, after an emergency hospital admission because of a sport-related thoracic trauma, a right inguinal lymph node biopsy demonstrated Hodgkin’s lymphoma Stage IVB (scleronodular mixed cell subtype). Although it was improved by chemotherapy, the disease suddenly relapsed, and a further lymph node biopsy was performed in 1998 confirming the same diagnosis. Despite further treatment, the patient died of septic shock in 2004, at the age of 38 years. Retrospective analysis of the various specimens showed intracellular heavy metal nanoparticles within lymph node, bone marrow, and liver samples by field emission gun environmental scanning electron microscopy and energy dispersive spectroscopy. Heavy metals from environmental pollution may accumulate in sites far from the entry route and, in genetically conditioned individuals with tissue specificity, may act as cofactors for chronic inflammation or even malignant transformation. The present anecdotal report highlights the need for further pathologic ultrastructural investigations using serial samples and the possible role of intracellular nanoparticles in human disease

Integrated Surveying System for Landslide Monitoring, Valoria Landslide (Appennines of Modena, Italy)

The research object is the study and prevention of landslide risk through the utilization of integrated surveying systems like GPS and Automatic Total Station (Robotic station).The measurements have been applied to Boschi di Valoria landslide, located on Appennines of Modena in the Northern Italy, which relatively large size, about 1.6 square km, required the use of both techniques. The system is made by Automatic Total Station, looking at 45 reflectors and a GPS master station, reference for three rovers on the landslide. In order to monitor "local" disturbing effects, a bi-dimensional clinometer has been applied on the pilaster where the total station is located. In a first periodically measurements were collected, while the system is now performing continuously. The system permitted to evaluate movements from few millimeter till some meters per day in most dangerous areas; the entity of the movements obliged to plan an alert system that was activated after a first phase of phenomenon study. Topographic measurements have been integrated with geotechnical sensors (inclinometers and piezometers) in a GIS for landslide risk management

Ceftazidime-avibactam resistance in Klebsiella pneumoniae sequence type 37: a decade of persistence and concealed evolution

The first reports of carbapenem-resistant Enterobacterales in our hospital date back to 2006. In that period, few ertapenem-resistant but meropenem-susceptible Klebsiella pneumoniae isolates belonging to sequence type (ST) 37 were retrieved from clinical samples. These strains produced the CTX-M-15 extended spectrum β-lactamase, OmpK35 was depleted due to a nonsense mutation, and a novel OmpK36 variant was identified. Yet, starting from 2010, Klebsiella pneumoniae carbapenemase (KPC)-producing ST512 isolates started prevailing and ST37 vanished from sight. Since 2018 the clinical use of the combination of ceftazidime-avibactam (CZA) has been introduced in clinical practice for the treatment of bacteria producing serine-β-lactamases, but KPC-producing, CZA-resistant K. pneumoniae are emerging. In 2021, four CZA-resistant ST37 isolates producing KPC variants were isolated from the same number of patients. blaKPC gene cloning in Escherichia coli was used to define the role of those KPC variants on CZA resistance, and whole genome sequencing was performed on these isolates and on three ST37 historical isolates from 2011. CZA resistance was due to mutations in the blaKPC genes carried on related pKpQIL-type plasmids, and three variants of the KPC enzyme have been identified in the four ST37 strains. The four ST37 isolates were closely related to each other and to the historical isolates, suggesting that ST37 survived without notice in our hospital for 10 years, waiting to re-emerge as a CZA-resistant K. pneumoniae clone. The ancestor of these contemporary isolates derives from ST37 wild-type porin strains, with no other mutations in chromosomal genes involved in conferring antibiotic resistance (parC, gyrA, ramR, mgrB, pmrB)