2,852 research outputs found
Ostracod and Foraminifer Responses to Late PleistoceneâHolocene Volcanic Activity in Northern Victoria Land as Recorded in Ross Sea (Antarctica) Marine Sediments
The impacts on ostracods and foraminifers caused by three Late Quaternary ashfalls of
different intensities and recovered in the ANTA02-NW2 core sediments (Drygalski Basin, western
Ross Sea) were analysed for the first time. Albeit with different timing, both associations demonstrated
similar response patterns associated with the deposition of material from volcanic eruptions.
In particular, based on the palaeontological evidence, it was possible to divide the cores into four
intervals/phases recording the evolution of the ecosystem before and after the deposition events: (1)
Pre-extinction phase (high abundance and high diversity values). (2) Extinction phase, characterised
by the complete disappearance of ostracod fauna; the foraminiferal assemblage, although not entirely
absent, records extremely low values of abundance and diversity (survivor assemblage). (3)
Recovery phase (increasing abundance and diversity values), characterised by the recolonisation of
some opportunistic taxa; species such as Australicythere devexa and Australicythere polylyca dominate
the ostracod assemblage. (4) Post-extinction phase (high abundance and high diversity values), with
the return to an environmental equilibrium characterised by the colonisation of specialised taxa such
as Argilloecia sp., Cytheropteron sp., Echinocythereis sp., and Hemicytherura spp. Our results may aid
in the understanding of how communities (i.e., ostracods and foraminifers) recovered after the impact
of direct deposits of volcanic ash into ocean waters. The mechanisms by which disappearance
and/or mortality was induced are still not clear. The release of toxic metals during the reaction of
the volcanic ash with seawater, the resulting chemical alteration in the seawater, and the change in
pH, together with the possible suppression of planktonic organisms, may have caused the two main
extinction phases recorded by the ANTA02-NW2 core sediments
Modelling Approach for NBSs Suitability Assessment in an Agricultural Area under Changing Climate Conditions: Case Studies in the Massaciuccoli Catchment (Central Italy)
Nature-Based Solutions (NBSs) are considered worldwide as a suitable approach for mitigating the impact of industrial agriculture on sediments and nutrient losses. However, their actual effectiveness is still questioned. In cases where site measurements of NBS performance are scarce, models can provide useful insights if accurately set. This study analyzed the effects of vegetated buffer strips (VBSs) and winter cover crops (WCCs) planted in some herbaceous cropping
systems within the Massaciuccoli reclamation area (Vecchiano, Central Italy). Analyses stem from modelling water and soil dynamics by applying SWAT+ at field scale on high resolution close-range photogrammetric digital terrain model (DTM), real crop rotations, and a detailed calendar of the main agronomic interventions. The NBS implementation was modelled in two experimental areas, showing contrasting soil properties. Comparing results from the modelling of different scenarios highlighted that NBS mitigative effect is influenced by soil properties and local topographic irregularities, which could induce concentrated flows. Long term climate changes can induce relevant different effects by varying the nature of soil
Ct-Guided Pancreatic Percutaneous Fine-needle Biopsy in Differential Diagnosis Between Pancreatic Cancer and Chronic Pancreatitis
Differential diagnosis between pancreatic cancer and chronic pancreatitis is still difficult to establish. In
63 patients with suspected pancreatic neoplasm we performed: serum CA 19-9 assessment, abdominal
ultrasound, CT scan and CT-guided pancreatic percutaneous fine-needle biopsy. The conclusive diagnosis
was pancreatic cancer in 40 patients and chronic pancreatitis in 23 patients. With regard to the differential
diagnosis, sensitivity and specificity were respectively 80% and 78% for serum CA 19-9, 75% and 65% for
abdominal US, 85% and 70% for CT scan, 00% and 87% for percutaneous fine-needle biopsy. We
conclude that CT-guided percutaneous fine-needle biopsy is the most reliable method for differential
diagnosis between pancreatic cancer and chronic pancreatitis
Premature aging and immune senescence in HIV-infected children
Objective: Several pieces of evidence indicate that HIV-infected adults undergo premature aging. The effect of HIV and antiretroviral therapy (ART) exposure on the aging process of HIV-infected children may be more deleterious since their immune system coevolves from birth with HIV.
Design: Seventy-one HIV-infected (HIV+), 65 HIV-exposed-uninfected (HEU), and 56 HIV-unexposed-uninfected (HUU) children, all aged 0\u20135 years, were studied for biological aging and immune senescence.
Methods: Telomere length and T-cell receptor rearrangement excision circle levels were quantified in peripheral blood cells by real-time PCR. CD4+ and CD8+ cells were analysed for differentiation, senescence, and activation/exhaustion markers by flow cytometry.
Results: Telomere lengths were significantly shorter in HIV+ than in HEU and HUU children (overall, P < 0.001 adjusted for age); HIV+ ART-naive (42%) children had shorter telomere length compared with children on ART (P = 0.003 adjusted for age). T-cell receptor rearrangement excision circle levels and CD8+ recent thymic emigrant cells (CD45RA+CD31+) were significantly lower in the HIV+ than in control groups (overall, P = 0.025 and P = 0.005, respectively). Percentages of senescent (CD28-CD57+), activated (CD38+HLA-DR+), and exhausted (PD1+) CD8+ cells were significantly higher in HIV+ than in HEU and HUU children (P = 0.004, P < 0.001, and P < 0.001, respectively). Within the CD4+ cell subset, the percentage of senescent cells did not differ between HIV+ and controls, but programmed cell death receptor-1 expression was upregulated in the former.
Conclusions: HIV-infected children exhibit premature biological aging with accelerated immune senescence, which particularly affects the CD8+ cell subset. HIV infection per se seems to influence the aging process, rather than exposure to ART for prophylaxis or treatmen
Use of deferoxamine (DFO) in transfusion-dependent ÎČ-thalassemia during pregnancy: A retrospective study.
Objective: To report cases of use of chelation therapy during pregnancy which resulted in favorable outcomes for the babies. Materials and methods: In this retrospective cohort study, we described the evolution and outcome of 9 pregnancies in Italian thalassemic women who received deferoxamine (DFO) inadvertently during early pregnancy. Results: The use of deferoxamine during first trimester did not lead to adverse effects on the fetus or cause major complications for the gestation, although an increase in iron burden was observed after suspending chelation therapy. Conclusion: In our experience, iron-chelation therapy might be administrated in pregnancy where the benefits to the mother outweigh the potential risks to the baby. Keywords: Deferoxamine, Iron chelation therapy, Magnetic resonance T2*, Pregnancy, Thalassemi
Historical explosive activity of Mount Melbourne Volcanic Field (Antarctica) revealed by englacial tephra deposits
Five tephra layers named BRH1 to 5 were sampled in an ice cliff located on the north-eastern flank of Mount Melbourne (northern Victoria Land, Antarctica). The texture, componentry, mineralogy, and major and trace element compositions of glass shards have been used to characterize these layers. These properties suggest that they are primary fall deposits produced from discrete eruptions that experienced varying degrees of magma/water interaction. The major and trace element glass shard analyses on single glass shards indicate that Mount Melbourne Volcanic Field is the source of these tephra layers and the geochemical diversity highlights that the eruptions were fed by compositionally diverse melts that are interpreted to be from a complex magma system with a mafic melt remobilizing more evolved trachy-andesitic to trachytic magma pockets. Geochemical compositions, along with textural and mineralogical data, have allowed correlations between two of the englacial tephra and distal cryptotephra from Mount Melbourne, recovered within a marine sediment core in the Edisto Inlet (~â280 km northeast of Mount Melbourne), and constrain the age of these englacial tephra layers to between the third and the fourth century CE. This work provides new evidence of the intense historical explosive activity of the Mount Melbourne Volcanic Field and better constrains the rates of volcanism in northern Victoria Land. These data grant new clues on the eruptive dynamics and tephra dispersal, and considerably expand the geochemical (major and trace elements) dataset available for the Mount Melbourne Volcanic Field. In the future, this will facilitate the precise identification of tephra layers from this volcanic source and will help define the temporal and spatial correlation between Antarctic records using tephra layers. Finally, this work also yields new valuable time-stratigraphic marker horizons for future dating, synchronization, and correlations of different palaeoenvironmental and palaeoclimatic records across large regions of Antarctica
Antagonism/Agonism modulation to build novel antihypertensives selectively triggering i1-imidazoline receptor activation
Pharmacological studies have suggested that I1-imidazoline receptors are involved in the regulation of cardiovascular function and that selective I1-agonists, devoid of the side effects associated with the common hypotensive α2-adrenoreceptor agonists, might be considered as a second generation of centrally acting antihypertensives. Therefore, in the present study, inspired by the antihypertensive behavior of our selective I1-agonist 4, we designed, prepared, and studied the novel analogues 5-9. A selective I1-profile, associated with significant hemodinamic effects, was displayed by 5, 8, and 9. Interestingly, the highest potency and longest lasting activity displayed by 8 (carbomethyline) suggested that van der Waals interactions, promoted by the ortho methyl decoration of its aromatic moiety, are particularly advantageous. In addition, in analogy to what was noted for (S)-(+)-4, the observation that only (S)-(+)-8 displayed significant hemodynamic effects unequivocally confirmed the stereospecific nature of the I1 proteins
Premature aging and immune senescence in HIV-infected children.
Objective: Several pieces of evidence indicate that HIV-infected adults undergo premature aging. The effect of HIV and antiretroviral therapy (ART) exposure on the aging process of HIV-infected children may be more deleterious since their immune system coevolves from birth with HIV. Design: Seventy-one HIV-infected (HIV+), 65 HIV-exposed-uninfected (HEU), and 56 HIV-unexposed-uninfected (HUU) children, all aged 0-5 years, were studied for biological aging and immune senescence. Methods: Telomere length and T-cell receptor rearrangement excision circle levels were quantified in peripheral blood cells by real-time PCR. CD4+ and CD8+ cells were analysed for differentiation, senescence, and activation/exhaustion markers by flow cytometry. Results: Telomere lengths were significantly shorter in HIV+ than in HEU and HUU children (overall, Pâ<â0.001 adjusted for age); HIV+ ART-naive (42%) children had shorter telomere length compared with children on ART (Pâ=â0.003 adjusted for age). T-cell receptor rearrangement excision circle levels and CD8+ recent thymic emigrant cells (CD45RA+CD31+) were significantly lower in the HIV+ than in control groups (overall, Pâ=â0.025 and Pâ=â0.005, respectively). Percentages of senescent (CD28âCD57+), activated (CD38+HLA-DR+), and exhausted (PD1+) CD8+ cells were significantly higher in HIV+ than in HEU and HUU children (Pâ=â0.004, Pâ<â0.001, and Pâ<â0.001, respectively). Within the CD4+ cell subset, the percentage of senescent cells did not differ between HIV+ and controls, but programmed cell death receptor-1 expression was upregulated in the former. Conclusions: HIV-infected children exhibit premature biological aging with accelerated immune senescence, which particularly affects the CD8+ cell subset. HIV infection per se seems to influence the aging process, rather than exposure to ART for prophylaxis or treatment. Keywords: immune activation, immune senescence, microbial translocation, pediatric HIV/AIDS, premature aging, telomere length, T-cell receptor rearrangement excision circl
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