1,058 research outputs found
Morphology and depth of reflectors from 2D non-linear inversion of seismic data
We present here two methods to obtain reflection images of upper
crust seismic reflectors. The techniques are based on migration and waveform
coherence analysis of reflected seismic phases recorded in local earthquake seismograms
and in active seismic data.
The first method is a move-out and stack of reflected seismic phases in local
earthquake recordings. The theoretical travel times of reflected/converted
phases in a 1D medium for a given interface depth and velocity model are used
to align the recordings in time. The locations and origin times of events are initially
estimated from the P and S arrival times. Different seismic gathers are
obtained for each reflected/converted phase at the interface under consideration,
and the best interface depth is chosen as that which maximizes the value
of a semblance function computed on moved-out records. This method has
been applied to seismic records of microearthquakes that have occurred at the
Mt. Vesuvius volcano, and it confirms the reports of an 8- to 10-km-deep seismic
discontinuity beneath the volcano that was previously identified as the
roof of an extended magmatic sill.
The second is a non-linear 2D method for the inversion of reflection travel
times aimed at the imaging of a target upper-crust reflector. This method is specifically
designed for geophysical investigations in complex geological environments
(oil investigations, retrieving of images of volcano structures) where the
presence of complex structures makes the standard velocity analysis difficult
and degrades the quality of migrated images. Our reflector is represented by
nodes of a cubic-spline that are equally spaced at fixed horizontal locations. The
method is based on a multiscale approach and uses a global optimization technique
(genetic algorithm) that explores the whole of the parameter space, i.e.
the interface position nodes. The forward problem (the modelling of reflection
travel times) is solved using the finite-difference solver of Podvine & Lecomte
(1991) and using an a priori known background velocity model. This non-linear
method allows the automated determination of the global minimum (or maximum)
without relying on estimates of the gradient of the objective function in
the starting model and without making assumptions about the nature of the
objective function itself. We have used two types of objective functions. The
first is a least-squares L2 norm, defined as the sum of the squared differences between the observed and the calculated travel times. The second is based on
coherence measures (semblance). The main advantage of using coherence
measures is that they do not require travel-time picking to assess the degree of
fit to the data model. Thus, the time performance of the whole procedure is
improved and the subjectivity of the human operators in the picking procedure
is removed.
The methods are tested on synthetic models and have been applied to a subset
of data that was collected during the active seismic experiments performed in
September 2001 in the gulfs of Naples and Pozzuoli in the framework of what
is known as the SERAPIS project
Unsulfated biotechnological chondroitin by itself as well as in combination with high molecular weight hyaluronan improves the inflammation profile in osteoarthritis in vitro model
Several studies suggest that inflammation has a pivotal role during the progression of osteoarthritis (OA) and cytokines have been identified as the main process mediators. This study aimed to explore the ability to modulate the main OA pro-inflammatory biomarkers of novel gels (H-HA/BC) based on high molecular weight hyaluronan (H-HA) and unsulfated biotechnological chondroitin (BC). For the first time, BC was tested also in combination with H-HA on human primary cells isolated from pathological knee joints. Specifically, the experiments were performed using an OA in vitro model based on human chondrocytes and synoviocytes. To evaluate the anti-inflammatory effects of H-HA/BC in comparison with H-HA and BC single gels, NF-kB, COMP-2, MyD88, MMP-13 and a wide range of cytokines, known to be specific biomarkers in OA (e.g., IL-6, IL-8, and TNF-α), were evaluated. In addition, cell morphology and proliferation occurring in the presence of either H-HA/BC or single components were assessed using time-lapse video microscopy. It was shown that synovial fluids and cells isolated from OA suffering patients, presented a cytokine pattern respondent to an ongoing inflammation status. H-HA and BC significantly reduced the levels of 23 biomarkers associated with cartilage damage. However, H-HA/BC decreased significantly 24 biological mediators and downregulated 19 of them more efficiently than the single components. In synoviocytes cultures, cytokine analyses proved that H-HA/BC gels re-established an extracellular environment more similar to a healthy condition reducing considerably the concentration of 11 analytes. Instead, H-HA and BC significantly modulated 7 (5 only with a longer treatment) and 8 biological cytokines, respectively. Our results suggest that H-HA/BC beyond the viscosupplementation effect typical for HA-based gels, can improve the inflammation status in joints and thus could be introduced as a valid protective and anti-inflammatory intraarticular device in the field of Class III medical devices for OA treatments
Liposome-mediated inhibition of inflammation by hydroxycitrate
Hydroxycitrate (HCA), a main organic acid component of the fruit rind of Garcinia cambogia, is a natural citrate analog that can inhibit the ATP citrate lyase (ACLY) enzyme with a consequent reduction of inflammatory mediators (i.e., nitric oxide (NO), reactive oxygen species (ROS), and prostaglandin E2 (PGE2)) levels. Therefore, HCA has been proposed as a novel means to prevent, treat, and ameliorate conditions involving inflammation. However, HCA presents a low membrane permeability, and a large quantity is required to have a biological effect. To overcome this problem, HCA was formulated in liposomes in this work, and the enhancement of HCA cell availability along with the reduction in the amount required to downregulate NO, ROS, and PGE2 in macrophages were assessed. The liposomes were small in size (~60 nm), monodispersed, negatively charged (−50 mV), and stable on storage. The in vitro results showed that the liposomal encapsulation increased by approximately 4 times the intracellular accumulation of HCA in macrophages, and reduced by 10 times the amount of HCA required to abolish LPS-induced NO, ROS, and PGE2 increase. This suggests that liposomal HCA can be exploited to target the citrate pathway involved in inflammatory processes
Medicinal plants and their bacterial microbiota: A review on antimicrobial compounds production for plant and human health
Medicinal plants (MPs) have been used since antiquity in traditional and popular medicine, and they represent a very important source of bioactive molecules, including antibiotic, antiviral, and antifungal molecules. Such compounds are often of plant origin, but in some cases, an origin or a modification from plant microbiota has been shown. Actually, the research continues to report the production of bioactive molecules by plants, but the role of plant–endophytic interaction is emerging. Classic examples are mainly concerned with fungal endophytes; however, it has been recently shown that bacterial endophytes can also play an important role in influencing the plant metabolism related to the synthesis of bioactive compounds. In spite of this, a deep investigation on the power of MP bacterial endophytes is lacking. Here, an overview of the studies on MP bacterial microbiota and its role in the production of plant antimicrobial compounds contributing to prime host defense system and representing a huge resource for biotech and therapeutic applications is provided
A small protein is involved in tryptophan biosynthesis and morpho-physiological differentiation in Streptomyces coelicolor
A small protein is involved in tryptophan biosynthesis and morpho-physiological differentiation in Streptomyces coelicolo
Medicinal Plants and Their Bacterial Microbiota: A Review on Antimicrobial Compounds Production for Plant and Human Health
Medicinal plants (MPs) have been used since antiquity in traditional and popular medicine, and they represent a very important source of bioactive molecules, including antibiotic, antiviral, and antifungal molecules. Such compounds are often of plant origin, but in some cases, an origin or a modification from plant microbiota has been shown. Actually, the research continues to report the production of bioactive molecules by plants, but the role of plant–endophytic interaction is emerging. Classic examples are mainly concerned with fungal endophytes; however, it has been recently shown that bacterial endophytes can also play an important role in influencing the plant metabolism related to the synthesis of bioactive compounds. In spite of this, a deep investigation on the power of MP bacterial endophytes is lacking. Here, an overview of the studies on MP bacterial microbiota and its role in the production of plant antimicrobial compounds contributing to prime host defense system and representing a huge resource for biotech and therapeutic applications is provided
Qalb ta’ Tifel
Ä abra ta’ poeżiji u proża li tinkludi: Lil Malta ta’ Dun Karm – Fuq il-Fruntiera ta’ Dun Karm – Jum li jibqa’ jissemma ta’ Ä użè Chetcuti – Xbihet Malta ta’ Arthur V. Vassallo – Għanja ta’ Mħabba ta’ Ä użè Chetcuti – Å»ewÄ¡ Poeżijiet tal-kittieb Malti Antonio Calleja ta’ A. C. – Twettiqa ta’ Calleja – Lil Ħabib Għeluq Sninu ta’ Calleja – Taħt is-Salib ta’ R. M. B. – Lil Dun Karm ta’ Fran. Camilleri – Frak mill-weraq ta’ Byron ta’ A. C. – Irrid Immur Ta’ Xbiex ta’ Fran. Camilleri – Il-Cottonera fil-Ħamrun ta’ N. Biancardi – Qalb ta’ Tifel ta’ R. M. B.N/
Air Raid
Ä abra ta’ poeżiji u proża li tinkludi: Dwejjaq Missirijietna ta’ Rużar Briffa – Xemx ta’ Settembru ta’ Vic. Apap – God Save the King ta’ Ä użè Galea – It-8 ta’ Settembru Londra, 1942 ta’ A. V. Vassallo – Wenzu jsib lil LuÄ‹ija f’Lazzarett ta’ Dun Pawl – MDLXV ta’ Albert M. Cassola – Innu lil San Duminku ta’ Gużman – Innu lill-Bambina – Il-Għanja tar-Rebħa! ta’ N. Biancardi – Air Raid ta’ E. Agius.N/
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