691 research outputs found
New resonance parameters for the stable tungsten isotopes from thermal to 1 keV
Neutron resonance parameters of the 182,183,184,186W isotopes were obtained by a resonance shape analysis of experimental data measured at the time-of-flight facility GELINA using the REFIT code. In this document the analysis procedures of capture and transmission data are described. The deduced resonance parameters have been adopted in the new release of the Joint Evaluated Fusion and Fission file, i.e. JEFF-3.2, maintained by the Nuclear Energy Agency of the OECD.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard
Near-field optical imaging and spectroscopy of a coupled quantum wire-dot structure
A coupled GaAs/AlGaAs quantum wire (QWR)-dot sample grown by molecular beam epitaxy on a patterned (311)A GaAs substrate is studied by near-field spectroscopy at a temperature of 10 K with a spectral resolution of 100 µeV. The two-dimensional potential energy profiles of the sample including localized excitonic states caused by structural disorder are determined in photoluminescence measurements with a spatial resolution of 150 nm. One finds a potential barrier of 20 meV between the quantum wire and the embedding quantum well (QW) on the mesa top of the structure. This is due to local thinning of the GaAs layer. In contrast, the wire-dot interface results free of energy barriers. The spatial variation of the GaAs layer thickness provides information on the growth mechanism determined by lateral diffusion of Ga atoms which is modeled by an analytical model. By performing spatially resolved photoluminescence excitation measurements on this wire-dot structure, we present a method for investigating carrier transport in low-dimensional systems: The dot area is used as an optical marker for excitonic diffusion via QW and QWR states. The two-dimensional (2D) and 1D diffusion coefficients are extracted as a function of the temperature and discussed
Temperature-dependent near-field imaging of delocalized and localized excitons in single quantum wires
Summary form only given. Recent microphotoluminescence studies have shown that the low-temperature emission spectra of semiconductor quantum wires are dominated by localized, quasi-zero-dimensional, excitons. This implies that both the optical and transport properties of such quasi-one-dimensional (Q1D) nanostructures are similar to that of a chain of quantum dots. It also hinders the observation of some truly one-dimensional quantum effects, such as the ballistic or diffusive one-dimensional exciton transport, expected in nanostructures containing Q1D excitons that are delocalized over mesoscopic length scales. We present the first experimental evidence for such delocalized excitons in a single quantum wire. A novel coupled quantum wire-dot nanostructure is studied by low temperature near-field photoluminescence (PL) spectroscopy
Inhibin reduces spermatogonial numbers in testes of adult mice and chinese hamsters
Bovine follicular fluid (bFF) injected ip in mice during 2 days (65,000 U inhibin/day, 1 U inhibin the activity in 1 /ÎĽg bFF protein) caused a significant decrease in the numbers of A4, intermediate (In), and B spermatogonia to 91%,74%, and 67% of the control values, respectively. The numbers of undifferentiated spermatogonia remained unchanged. These injections suppressed peripheral FSH levels to 6% of the control values, suggesting that FSH might be the modulator of the effects on spermatogenesis. However, in the Chinese hamster, intratesticular injections of bFF during 4 days (6500 U inhibin/day into one testis) also caused a significant decrease in the numbers of A3, In, B1, and B2 spermatogonia to 86%, 61%, 55%, and 94% of the control values, respectively. Similarly, treatment with a partially purified inhibin preparation from rat Sertoli cell-conditioned medium (rSCCM) during 4 days (Mono Q fraction; 1512 U inhibin/day; 37.8 ÎĽg protein) caused a significant decrease in the numbers of A3, In, B1, and B2 spermatogonia to 90%, 87%, 66%, and 93% of the control values, respectively. Treatment with a highly purified inhibin preparation from rSCCM during 4 days (30K inhibin; 750 U inhibin/day; 100 ng protein) significantly decreased the numbers of In and B1 spermatogonia to, respectively, 87% and 91% of the control values. These effects were limited to the testis into which the material was injected; the contralateral testis or testes injected with control fluid always showed normal numbers of spermatogonia. This implies that the effects on the seminiferous epithelium are not FSH mediated. Intratesticular injections of bFF or pure inhibin did not affect the number of undifferentiated spermatogonia. However, the Mono Q fraction caused a significant increase in the numbers of undifferentiated spermatogonia in stages IV-VII of the cycle, suggesting the presence of a mitogenic factor for undifferentiated spermatogonia in rSCCM which is not present or is counteracted in bFF. The results suggest that inhibin may have a role in the regulation of spermatogonial development in the adult animal
Germano Sartelli
Libro-catalogo della mostra sugli artisti imolesi che hanno partecipato alle Biennali Internazionali d'arte di Venezia. Capitolo dedicato all'opera dello scultore Germano Sartelli, tra i principali esponenti dell'informale italiano
Genomic, Molecular, and Phenotypic Characterization of Arthrobacter sp. OVS8, an Endophytic Bacterium Isolated from and Contributing to the Bioactive Compound Content of the Essential Oil of the Medicinal Plant Origanum vulgare L.
Medicinal plants play an important role in the discovery of new bioactive compounds with antimicrobial activity, thanks to their pharmacological properties. However, members of their microbiota can also synthesize bioactive molecules. Among these, strains belonging to the genera Arthrobacter are commonly found associated with the plant’s microenvironments, showing plant growth-promoting (PGP) activity and bioremediation properties. However, their role as antimicrobial secondary metabolite producers has not been fully explored. The aim of this work was to characterize the Arthrobacter sp. OVS8 endophytic strain, isolated from the medicinal plant Origanum vulgare L., from molecular and phenotypic viewpoints to evaluate its adaptation and influence on the plant internal microenvironments and its potential as a producer of antibacterial volatile molecules (VOCs). Results obtained from the phenotypic and genomic characterization highlight its ability to produce volatile antimicrobials effective against multidrug-resistant (MDR) human pathogens and its putative PGP role as a producer of siderophores and degrader of organic and inorganic pollutants. The outcomes presented in this work identify Arthrobacter sp. OVS8 as an excellent starting point toward the exploitation of bacterial endophytes as antibiotics sources
Experimental Engineering of Arbitrary Qudit States with Discrete-Time Quantum Walks
The capability to generate and manipulate quantum states in high-dimensional Hilbert spaces is a crucial step for the development of quantum technologies, from quantum communication to quantum computation. One-dimensional quantum walk dynamics represents a valid tool in the task of engineering arbitrary quantum states. Here we affirm such potential in a linear-optics platform that realizes discrete-time quantum walks in the orbital angular momentum degree of freedom of photons. Different classes of relevant qudit states in a six-dimensional space are prepared and measured, confirming the feasibility of the protocol. Our results represent a further investigation of quantum walk dynamics in photonics platforms, paving the way for the use of such a quantum state-engineering toolbox for a large range of applications
Risk factors for pre-clinical atherosclerosis in adolescents with type 1 diabetes
Aims: To assess whether, besides "traditional" risk factors, overall oxidative stress, oxidized lipoproteins, and glycemic variability are associated with early macro-vascular damage in type 1 diabetes (T1D). Methods: In 267 children/adolescents with T1D (130 girls, age 9.1-23.0 years) we evaluated: derivatives of reactive oxygen metabolites [d-ROMs], serum total antioxidant capacity [TAC] and oxidized LDL-cholesterol [oxLDL]; markers of early vascular damage (Lipoprotein-associated phospholipase A2 [Lp-PLA2], z-score of carotid intima-media thickness [z-cIMT] and carotid-femoral pulse wave velocity [z-PWV]); CGM metrics of four weeks preceding the visit, central systolic/diastolic blood pressures (cSBP/cDBP), and HbA1c, z-score of BP (z-SBP/z-DBP) and circulating lipids longitudinally collected since T1D onset.. Three general linear models were built with z-cIMT, z-PWV adjusted for current cDBP, and Lp-PLA2 as independent variables. Results: The z-cIMT was associated with male gender (B = 0.491, η2 = 0.029, p = 0.005), cSBP (B = 0.023, η2 = 0.026, p = 0.008) and oxLDL (B = 0.022, η2 = 0.022, p = 0.014). The z-PWV was associated with diabetes duration (B = 0.054, η2 = 0.024, p = 0.016), daily insulin dose (B = 0.52, η2 = 0.018, p = 0.045), longitudinal z-SBP (B = 0.18, η2 = 0.018, p = 0.045) and dROMs (B = 0.003, η2 = 0.037, p = 0.004). Lp-PLA2 was associated with age (B = 0.221, η2 = 0.079, p = 3*10-6), oxLDL (B = 0.081, η2 = 0.050, p = 2*10-4), longitudinal LDL-cholesterol (B = 0.031, η2 = 0.043, p = 0.001) and male gender (B = -1.62, η2 = 0.10, p = 1.3*107). Conclusions: Oxidative stress, male gender, insulin dose, diabetes duration and longitudinal lipids and blood pressure, contributed to the variance of early vascular damage in young patients with T1D
Thermal treatment of magnesium particles in polylactic acid polymer films elicits the expression of osteogenic differentiation markers and lipidome profile remodeling in human adipose stem cells
The efficacy of polylactic acid (PLA)/Magnesium (Mg)-based materials for driving stem cells toward bone tissue engineering applications requires specific Mg surface properties to modulate the interface of stem cells with the film. Here, we have developed novel PLA/Mg-based composites and explored their osteogenic differentiation potential on human adipose stem cells (hASCs). Mg-particles/polymer interface was improved by two treatments: heating in oxidative atmosphere (TT) and surface modification with a compatibilizer (PEI). Different contents of Mg particles were dispersed in PLA and composite surface and bulk properties, protein adsorption, stem cell-PLA/Mg interactions, osteogenic markers expressions, and lipids composition profile were evaluated. Mg particles were uniformly distributed on the surface and in the bulk PLA polymer. Improved and modulated particle-polymer adhesion was observed in Mg particle-treated composites.
After 21 days in canonical growth culture conditions, hASCs on PLA/MgTT displayed the highest expression of the general osteogenic markers, RUNX2, SSP1, and BGLAP genes, Alkaline Phosphatase, type I Collagen, Osteopontin, and Calcium deposits. Moreover, by LC/MS QTOF mass-spectrophotometry lipidomic analysis, we found in PLA/MgTT-cells, for the first time, a remodeling of the lipid classes composition associated with the osteogenic differentiation. We ascribed these results to MgTT characteristics, which improve Mg availability and composite osteoinductive performance.This work has been carried out within the M-ERANET Programme: Project POLYMAGIC. A. Ferrandez-Montero thanks Project ADITIMAT-CM: FabricaciĂłn aditiva: del material a la aplicaciĂłn. S2018/NMT-4411. M. Lieblich thanks Project PID2019-104351GB-C21 financed by MCIN/AEI/10.13039/501100011033
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