421 research outputs found
The potential of Antheraea pernyi silk for spinal cord repair
This work was supported by the Institute of Medical Sciences of the University of Aberdeen, Scottish Rugby Union and RS McDonald Charitable Trust. We are grateful to Mr Nicholas Hawkins from Oxford University and Ms Annette Raffan from the University of Aberdeen for assistance with tensile testing. We thank Ms Michelle Gniβ for her help with the microglial response experiments. We also thank Mr Gianluca Limodio for assisting with the MATLAB script for automation of tensile testing’s data analysis.Peer reviewedPublisher PD
Analysis of the seismic site effects along the ancient Via Laurentina (Rome)
This paper presents an evaluation of the Local Seismic Response (LSR)
along the route of the ancient Roman road Via Laurentina, which has
been exposed in several areas of southwest Rome over the last decade
during the construction of new buildings and infrastructures. It is
an example of LSR analysis applied to ancient and archaeological
sites located in alluvial valleys with some methodological inferences
for the design of infrastructure and urban planning. Since the ancient
road does not cross the alluvial valley (namely the Fosso di Vallerano
Valley) normal to its sides, it was not possible to directly perform
2D numerical modelling to evaluate the LSR along the road route.
Therefore, outputs of 2D numerical models, obtained along three cross
sections that were normal oriented respect to the valley, were projected
along the route of the Via Laurentina within a reliable buffer attributed
according to an available high-resolution geological model of the
local subsoil. The modelled amplification functions consider physical
effects due to both the 2D shape of the valley and the heterogeneities
of the alluvial deposits. The 1D and 2D amplification functions were
compared to output that non-negligible effects are related to the narrow
shape of the fluvial valley and the lateral contacts between the
lithotecnical units composing the alluvial fill. The here experienced
methodology is suitable for applications to the numerical modelling of
seismic response in case of linear infrastructures (i.e., roads, bridges,
railways) that do not cross the natural system along physically characteristic
directions (i.e. longitudinally or transversally)
Posthumous sperm retrieval: A procreative revolution
Aim Postmortem sperm retrieval with consequent artificial insemination has become a technically possible option for future use in assisted reproductive technology (ART). The authors have set out to discuss the social and ethical significance of posthumous sperm retrieval, and the laws currently in force in Italy, the United States and elsewhere. Methods International literature from 1997 to 2020 has been reviewed from Pubmed database, Google Scholar and Scopus, drawn upon American, Italian and international sources (an ethically acceptable solution can only be achieved through an over-haul of the laws currently in effect). One of the most contentious issues was about donor consent. In Italy, a donor's will to retrieve his sperm in the event of premature disappearance can be proven according to the Law 219/2017, through advance health care directives. Results A substantial increase, both in requests and protocols, was documented in the United States. In Italy, over the last two years, three rulings were issued concerning posthumous insemination. However, no official standardized protocols, guidelines or targeted legislation exist at the national level to regulate medical activity in that realm, whereas established laws often set implicit limitations. Conclusion Current legal frameworks appear to be inadequate, because in most cases they were conceived under conditions that have radically changed. The need for newly-updated regulatory frameworks to promptly bridge that gap is increasingly clear, if current social needs related to reproductive rights are to be met in the foreseeable future
Lega eutettica Pb-Bi allo stato liquido: studio dell’ordine a breve raggio
La conoscenza delle modifiche strutturali che avvengono nella lega eutettica Pb-Bi (LBE) allo stato liquido èimportante sia da un punto di vista scientifico che applicativo. Questa lega è stata selezionata come liquidodi raffreddamento e come sorgente di neutroni di spallazione nello sviluppo di MYRRHA (ADS), quindi le sueproprietà termo-fisiche giocano un ruolo molto importante.Esperimenti di Spettroscopia Meccanica [1-2] evidenziano nella lega allo stato liquido la presenza di un ampiomassimo di frizione interna e una grossa variazione del modulo elastico tra 350 °C e 520 °C. Dopo fusione ilmodulo elastico della lega decresce in maniera costante fino a ~350 °C, poi a 400 °C si registra un brusco caloche copre un intervallo di temperatura di circa 170 °C, infine, sopra 520 °C il modulo continua a decrescere conuna pendenza molto simile a quella iniziale.Lo scopo di questo lavoro è stato quello di investigare mediante diffrazione X ad alta temperatura (HT-XRD)la struttura della lega LBE e la sua evoluzione in un esteso intervallo di temperatura (fino a 720 °C). I risultatimostrano che l’ordine a breve raggio della lega subito dopo fusione corrisponde a una struttura cubo-ottaedricache progressivamente evolve verso una struttura icosaedrica al crescere della temperatura. Tale trasformazione sicompleta intorno a 720 °C
Lymph node fine needle cytology, Epstein Barr virus infection and Hodgkin Lymphoma
Epstein-Barr virus (EBV) is a double-strand DNA virus of the herpes family; it is one of the most common human viruses and it is associated with a wide spectrum of benign and malignant conditions. EBV is related to the development of several neoplasms, globally 1% of tumours, including lymphoproliferative, epithelial and mesenchymal neoplasm. Lymphoproliferative disorders include Hodgkin lymphoma (HL) and B and T cell non-Hodgkin lymphoma. HL is one of the most common lymphoma in the developed world, affecting both young people and adults. HL pathogenesis is complex and includes various and partially unknown mechanisms. EBV has been detected in some HL neoplastic cells and expresses genes with a potential oncogenic function, therefore many studies suggest that viral infections have a causative role in neoplastic transformation. Fine Needle Cytology (FNC) is extensively used in the first diagnosis of any lymph-nodal enlargement, including reactive lymphadeno - pathies and lymphoproliferative processes; therefore cytopathologists are likely to encounter EBVassociated malignancies in cytology samples, mainly HL, which is one of the most common lymphoma. This study focuses on the cytological features and ancillary studies required to diagnose EBV-related HL
Laser pulse effects on plasma-sprayed and bulk tungsten
Tungsten (W) is considered a promising plasma-facing material for protecting the divertor of the ITER (International Thermonuclear Experimental Reactor). The effects on W of transient thermal loads of high energy occurring in a tokamak under operative conditions have been simulated through a single laser pulse delivered by an Nd:YAG laser. Bulk and plasma-sprayed (PS) samples have been submitted to tests and successively examined via SEM (scanning electron microscopy) observations. In both types of materials, the laser pulse induces similar effects: (i) a crater forms in the spot central area; (ii) all around the area, the ejection and the movement of molten metal give rise to a ridge; (iii) in a more external area, the surface shows plates with jagged boundaries and cracks induced by thermal stresses; (iv) the pores present in the original material become preferred ablation sites. However, the affected surface area in PS samples is larger and asymmetric if compared to that of bulk material. Such a difference has been explained by considering how microstructural characteristics influence heat propagation from the irradiated spot, and it was found that grain size and shape play a decisive role
photochemical performance of carpobrotus edulis in response to various substrate salt concentrations
Abstract Substrate salinity is one of the main abiotic factors limiting plant establishment, growth and distribution in coastal habitats. Nevertheless, few studies have investigated the interaction between salt concentration and duration of exposure on the physiology and growth of Carpobrotus edulis, an important invasive plant species growing in coastal dune habitats. In this study, four salinity treatment cycles of different length (three, six, twelve and twenty-four days) at salinity of 0 M, 0.1 M, 0.2 M and 0.3 M were imposed. A significant response in plant growth was elicited after 24 days of treatment. The main shoot length (MSL) and stem biomass (SBMS) increased by 11% and 4%, respectively at 0.1 M and by 25% and 6% at 0.2 M compared with the control. At 0.3 M MSL did not significantly differ from the control while SBMS was 18% lower. Moreover, C. edulis showed a high photoprotection mechanism efficiency resulting in a high carotenoid to chlorophyll ratio increase which was two, three and four times higher than the control at 0.1 M, 0.2 M and 0.3 M, respectively. Photochemically, the quantum yield of photosynthesis (ΦPSII) was 17%, 50% and 52% lower than the control at 0.1 M, 0.2 M and 0.3 M. The ΦPSII decrease was associated with a low leaf nitrogen content (NL) decrease (16%, 21% lower than the control at 0.1 M and 0.2 M, respectively). By contrast, NL had the highest decrease (41% lower than the control) at 0.3 M, which constrains the growth capacity. Overall, C. edulis was able to modulate its response to salinity. The salt stimulated shoot elongation at low or moderate salt concentrations could confer a competitive advantage making C. edulis even more efficient in establishing within the areas which it colonizes. Since the expansion of C. edulis may be enhanced by the forecasted increase in soil salinity, it will be of paramount importance to apply effective management practices in areas invaded by C. edulis to limit its expansion and preserve the native plant biodiversity
Study of 13CR-4NI-(MO) (F6NM) steel grade heat treatment for maximum hardness control in industrial heats
The standard NACE MR0175 (ISO 15156) requires a maximum hardness value of 23 HRC for 13Cr-4Ni-(Mo) steel grade for sour service, requiring a double tempering heat treatment at temperature in the range 648–691°C for the first tempering and 593–621°C for the second tempering. Difficulties in limiting alloy hardness after the tempering of forged mechanical components (F6NM) are often faced. Variables affecting the thermal behavior of 13Cr-4Ni-(Mo) during single and double tempering treatments have been studied by means of transmission electron microscopy (TEM) observations, X-ray diffraction measurements, dilatometry, and thermo-mechanical simulations. It has been found that relatively low Ac1 temperatures in this alloy induce the formation of austenite phase above 600°C during tempering, and that the formed, reverted austenite tends to be unstable upon cooling, thus contributing to the increase of final hardness via transformation to virgin martensite. Therefore, it is necessary to increase the Ac1 temperature as much as possible to allow the tempering of martensite at the temperature range required by NACE without the detrimental formation of virgin martensite upon final cooling. Attempts to do so have been carried out by reducing both carbon (<0.02% C) and nitrogen (<100 ppm) levels. Results obtained herein show final hardness below NACE limits without an unacceptable loss of mechanical strength
Cr segregation and impact fracture in a martensitic stainless steel
The fracture surfaces of a 10.5 wt.% Cr martensitic stainless steel broken in Charpy tests have been investigated through X-ray photoelectron spectroscopy (XPS). The specimens have been examined in two different conditions: as-quenched and heat treated for 10 h at 700°C. The trends of Fe/Cr ratio vs. test temperature are similar to the sigmoidal curves of absorbed energy and, after both ductile and quasi-cleavage brittle fractures, such ratio is always significantly lower than the nominal value of the steel chemical composition. Cr segregation does not occur on a macroscopic scale but takes place in microscopic zones which represent weaker spots in the steel matrix and a preferred path for moving cracks. Small area (diameter 300 μm) XPS measurements evidenced a higher density of such microscopic zones in the inner part of probes; this is explained by the different diffusion length of Cr atoms in the external and inner parts during quenching from austenitic field which has been calculated through FEM simulations. No significant differences of Cr concentration were observed in fracture surfaces of probes with and without heat treatment. The results highlight how Cr segregation plays a role not only in the intergranular mode of fracture but also in the quasi-cleavage and ductile ones
- …