74 research outputs found

    Violent and mild relaxation of an isolated self-gravitating uniform and spherical cloud of particles

    Full text link
    The collapse of an isolated, uniform and spherical cloud of self-gravitating particles represents a paradigmatic example of a relaxation process leading to the formation of a quasi-stationary state in virial equilibrium. We consider several N-body simulations of such a system, with the initial velocity dispersion as a free parameter. We show that there is a clear difference between structures formed when the initial virial ratio is b_0 =2K_0/W_0 < b_0^c ~ -1/2 and b_0> b_0^c. These two sets of initial conditions give rise respectively to a mild and violent relaxation occurring in about the same time scale: however in the latter case the system contracts by a large factor, while in the former it approximately maintains its original size. Correspondingly the resulting quasi equilibrium state is characterized by a density profile decaying at large enough distances as ~1/r^4 or with a sharp cut-off. The case b_0<b_0^c can be well described by the Lynden-Bell theory of collisionless relaxation considering the system confined in a box. On the other hand the relevant feature for b_0>b_0^c is the ejection of particles and energy, which is not captured by such a theoretical approach: for this case we introduce a simple physical model to explain the formation of the power-law density profile. This model shows that the behavior n(r) ~1/r^4 is the typical density profile that is obtained when the initial conditions are cold enough that mass and energy ejection occurs. In addition, we clarify the origin of the critical value of the initial virial ratio b_0^c.Comment: 15 pages, 17 figures, accepted for publication in Mon.Not.R.Acad.Soc. Version v2 with some minor changes to match the published version. References and 1 figure adde

    Severe Milk-Alkali Syndrome in a Patient with Hypoparathyroidism Associated with 1,25(OH)2D, Hydrochlorothiazide and Anthranoid Laxative Consumption

    Get PDF
    Background: Milk-alkali syndrome is a life-threatening condition defined by the triad of hypercalcaemia, metabolic alkalosis and acute renal failure, and is associated with consumption of calcium and absorbable alkali. Methods: We report the case of a patient admitted to a step-down unit of a large hospital in Italy. Results: The patient was a 59-year-old woman with hypoparathyroidism and mild chronic kidney insufficiency, treated for a preceding episode of hypocalcaemia with high doses of calcitriol and calcium carbonate, who was also taking hydrochlorothiazide and unreported herbal anthranoid laxatives. The patient was admitted to hospital with severe hypercalcaemia, severe metabolic alkalosis and acute renal insufficiency. The patient was successfully treated with urgent dialysis, loop diuretics and calcitonin administration. Conclusions: This case underlines the need for caution when treating patients with impaired calcium metabolism regulation, and suggests that herbal anthranoid laxatives might act as triggers for milk-alkali syndrome.

    Distribution of telecom Time-Bin Entangled Photons through a 7.7 km Hollow-Core Fiber

    Full text link
    State of the art classical and quantum communication rely on standard optical fibers with solid cores to transmit light over long distances. However, recent advances have led to the emergence of hollow-core optical fibers (HCFs), which due to the novel fiber geometry, show remarkable optical guiding properties, which are not as limited by the material properties as solid-core fibers. In this paper, we explore the transmission of entangled photons through a novel 7.7 km HCF, presenting the first successful demonstration of entanglement distribution via long-distance HCF. Our study highlights the low latency and low chromatic dispersion intrinsic to HCF, which can increase the secure key rate in time-bin based quantum key distribution protocols.Comment: 9 pages (incl. 2 pages appendix), 5 figure

    Two-stage turnbull-cutait pull-through coloanal anastomosis for low rectal cancer: a randomized clinical trial

    Get PDF
    Importance: two-stage Turnbull-Cutait pull-through hand-sewn coloanal anastomosis seems to provide benefits in terms of postoperative morbidity compared with standard hand-sewn coloanal anastomosis associated with diverting ileostomy and further ileostomy reversal in patients operated on for low rectal cancer. Objective: to compare 30-day postoperative and 1-year follow-up results of Turnbull-Cutait pull-through hand-sewn coloanal anastomosis and standard hand-sewn coloanal anastomosis after ultralow rectal resection for rectal cancer. Design, setting, and participants: multicenter randomized clinical trial. Neither patients nor surgeons were blinded for technique. Patients were recruited in 3 centers, Bellvitge University Hospital and Valle d'Hebron University Hospital in Spain and Instituto Nazionale Tumori Fondazione G. Pascale-Istituto di Ricovero e Cura a Carattere Scientifico in Italy. Patients undergoing ultralow anterior rectal resection needing hand-sewn coloanal anastomosis were randomly assigned to 2-stage Turnbull-Cutait pull-through hand-sewn coloanal anastomosis or standard hand-sewn coloanal anastomosis associated with diverting ileostomy. Data were analyzed between June 2012 and October 2018. Interventions: all patients underwent ultralow anterior resection. Patients assigned to the 2-stage Turnbull-Cutait pull-through group underwent exteriorization of a segment of left colon through the anal canal and, after 6 to 10 days, the exteriorized colon was resected and a delayed hand-sewn coloanal anastomosis was performed. For patients assigned to standard coloanal anastomosis, the hand-sewn coloanal anastomosis was performed with diverting ileostomy at first operation. Closure of the ileostomy was planned after 6 to 8 months. Main outcomes and measures: primary outcome was 30-day postoperative morbidity. For the standard hand-sewn coloanal anastomosis with diverting ileostomy group, overall postoperative morbidity includes 30-day postoperative complications of the ileostomy closure. Results: ninety-two white patients, 72 men and 20 women, with a median age of 62 years, were randomized and included in the analysis. Forty-six patients received standard hand-sewn coloanal anastomosis with diverting ileostomy and 46 received the 2-stage pull-through hand-sewn coloanal anastomosis. Seven patients (15.2%) in the standard hand-sewn coloanal anastomosis group did not undergo reversal ileostomy, and 1 patient (2.2%) in the 2-stage pull-through hand-sewn coloanal anastomosis group did not undergo delayed coloanal anastomosis. The 30-day overall composite postoperative complications rate was similar between the 2 groups (34.8% in 2-stage pull-through hand-sewn coloanal anastomosis group vs 45.7% in standard hand-sewn coloanal anastomosis group; P = .40), with a difference of -10.9 (95% CI, -29.5 to 8.9). Conclusions and relevance: the 2-stage pull-through hand-sewn coloanal anastomosis after ultralow anterior resection for low rectal cancer is safe and does not increase the postoperative morbidity rate compared with standard coloanal anastomosis with covering ileostomy followed by ileostomy closure

    Dissecting Out the Molecular Mechanism of Insecticidal Activity of Ostreolysin A6/Pleurotolysin B Complexes on Western Corn Rootworm

    Get PDF
    Ostreolysin A6 (OlyA6) is a protein produced by the oyster mushroom (Pleurotus ostreatus). It binds to membrane sphingomyelin/cholesterol domains, and together with its protein partner, pleurotolysin B (PlyB), it forms 13-meric transmembrane pore complexes. Further, OlyA6 binds 1000 times more strongly to the insect-specific membrane sphingolipid, ceramide phosphoethanolamine (CPE). In concert with PlyB, OlyA6 has potent and selective insecticidal activity against the western corn rootworm. We analysed the histological alterations of the midgut wall columnar epithelium of western corn rootworm larvae fed with OlyA6/PlyB, which showed vacuolisation of the cell cytoplasm, swelling of the apical cell surface into the gut lumen, and delamination of the basal lamina underlying the epithelium. Additionally, cryo-electron microscopy was used to explore the membrane interactions of the OlyA6/PlyB complex using lipid vesicles composed of artificial lipids containing CPE, and western corn rootworm brush border membrane vesicles. Multimeric transmembrane pores were formed in both vesicle preparations, similar to those described for sphingomyelin/cholesterol membranes. These results strongly suggest that the molecular mechanism of insecticidal action of OlyA6/PlyB arises from specific interactions of OlyA6 with CPE, and the consequent formation of transmembrane pores in the insect midgut

    Valorization of traditional Italian walnut (Juglans regia L.) production: genetic, nutritional and sensory characterization of locally grown varieties in the Trentino region

    Get PDF
    15openYesJuglans regia (L.) is cultivated worldwide for its nutrient-rich nuts. In Italy, despite the growing demand, walnut cultivation has gone through a strong decline in recent decades, which led to Italy being among the top five net importing countries. To promote the development of local high-quality Italian walnut production, we devised a multidisciplinary project to highlight the distinctive traits of three varieties grown in the mountainous region Trentino (northeast of Italy): the heirloom ‘Bleggiana’, a second local accession called local Franquette and the French cultivar ‘Lara’, recently introduced in the local production to increase yield. The genetic characterization confirmed the uniqueness of ‘Bleggiana’ and revealed local Franquette as a newly described autochthonous variety, thus named ‘Blegette’. The metabolic profiles highlighted a valuable nutritional composition of the local varieties, richer in polyphenols and with a lower ω-6/ω-3 ratio than the commercial ‘Lara’. ‘Blegette’ obtained the highest preference scores from consumers for both the visual aspect and tasting; however, the volatile organic compound profiles did not discriminate among the characterized cultivars. The described local varieties represent an interesting reservoir of walnut genetic diversity and quality properties, which deserve future investigation on agronomically useful traits (e.g., local adaptation and water usage) for a high-quality and sustainable production.Di Pierro, Erica A.; Franceschi, Pietro; Endrizzi, Isabella; Farneti, Brian; Poles, Lara; Masuero, Domenico; Khomenko, Iuliia; Trenti, Francesco; Marrano, Annarita; Vrhovsek, Urska; Gasperi, Flavia; Biasioli, Franco; Guella, Graziano; Bianco, Luca; Troggio, MichelaDi Pierro, E.A.; Franceschi, P.; Endrizzi, I.; Farneti, B.; Poles, L.; Masuero, D.; Khomenko, I.; Trenti, F.; Marrano, A.; Vrhovsek, U.; Gasperi, F.; Biasioli, F.; Guella, G.; Bianco, L.; Troggio, M

    COVID-19 in the tonsillectomised population

    Get PDF
    Objective: Interactions between SARS-CoV-2 and pharyngeal associated lymphoid tissue are thought to influence the manifestations of COVID-19. We aimed to determine whether a previous history of tonsillectomy, as a surrogate indicator of a dysfunctional pharyngeal associated lymphoid tissue, could predict the presentation and course of COVID-19. Methods: Multicentric cross-sectional observational study involving seven hospitals in Northern and Central Italy. Data on the clinical course and signs and symptoms of the infection were collected from 779 adults who tested positive for SARS-CoV-2, and analysed in relation to previous tonsillectomy, together with demographic and anamnestic data. Results: Patients with previous tonsillectomy showed a greater risk of fever, temperature higher than 39°C, chills and malaise. No significant differences in hospital admissions were found. Conclusions: A previous history of tonsillectomy, as a surrogate indicator of immunological dysfunction of the pharyngeal associated lymphoid tissue, could predict a more intense systemic manifestation of COVID-19. These results could provide a simple clinical marker to discriminate suspected carriers and to delineate more precise prognostic models

    Localisation of gamma-ray bursts from the combined SpIRIT+HERMES-TP/SP nano-satellite constellation

    Full text link
    Multi-messenger observations of the transient sky to detect cosmic explosions and counterparts of gravitational wave mergers critically rely on orbiting wide-FoV telescopes to cover the wide range of wavelengths where atmospheric absorption and emission limit the use of ground facilities. Thanks to continuing technological improvements, miniaturised space instruments operating as distributed-aperture constellations are offering new capabilities for the study of high energy transients to complement ageing existing satellites. In this paper we characterise the performance of the upcoming joint SpIRIT + HERMES-TP/SP nano-satellite constellation for the localisation of high-energy transients through triangulation of signal arrival times. SpIRIT is an Australian technology and science demonstrator satellite designed to operate in a low-Earth Sun-synchronous Polar orbit that will augment the science operations for the equatorial HERMES-TP/SP. In this work we simulate the improvement to the localisation capabilities of the HERMES-TP/SP when SpIRIT is included in an orbital plane nearly perpendicular (inclination = 97.6^\circ) to the HERMES orbits. For the fraction of GRBs detected by three of the HERMES satellites plus SpIRIT, the combined constellation is capable of localising 60% of long GRBs to within ~ 30 deg2^2 on the sky, and 60% of short GRBs within ~ 1850 deg2^2. Based purely on statistical GRB localisation capabilities (i.e., excluding systematic uncertainties and sky coverage), these figures for long GRBs are comparable to those reported by the Fermi GBM. Further improvements by a factor of 2 (or 4) can be achieved by launching an additional 4 (or 6) SpIRIT-like satellites into a Polar orbit, which would both increase the fraction of sky covered by multiple satellite elements, and enable \geq 60% of long GRBs to be localised within a radius of ~ 1.5^\circ on the sky.Comment: 17 pages, 10 figures, 1 table. Accepted for publication in PAS

    Profession, Professionalität, Professionalisierung

    Get PDF
    Alignment of LH receptor amino acid sequences obtained from the UniProt database ( http://www.uniprot.org ). Homo sapiens LHCGR (UniProt identifier: P22888), Mus musculus Lhr (P30730) and Rattus norvegicus Lhr (P16235) sequences were aligned by the UniProt online tool Clustal Omega 1.2.1 ( http://www.uniprot.org/align ). Boxes indicate sequence divergence; :=conservation of strong groups;. = conservation of weak groups or no consensus. (DOC 92 kb

    Lipoprotein(a) Genotype Influences the Clinical Diagnosis of Familial Hypercholesterolemia

    Get PDF
    : Background Evidence suggests that LPA risk genotypes are a possible contributor to the clinical diagnosis of familial hypercholesterolemia (FH). This study aimed at determining the prevalence of LPA risk variants in adult individuals with FH enrolled in the Italian LIPIGEN (Lipid Transport Disorders Italian Genetic Network) study, with (FH/M+) or without (FH/M-) a causative genetic variant. Methods and Results An lp(a) [lipoprotein(a)] genetic score was calculated by summing the number risk-increasing alleles inherited at rs3798220 and rs10455872 variants. Overall, in the 4.6% of 1695 patients with clinically diagnosed FH, the phenotype was not explained by a monogenic or polygenic cause but by genotype associated with high lp(a) levels. Among 765 subjects with FH/M- and 930 subjects with FH/M+, 133 (17.4%) and 95 (10.2%) were characterized by 1 copy of either rs10455872 or rs3798220 or 2 copies of either rs10455872 or rs3798220 (lp(a) score ≥1). Subjects with FH/M- also had lower mean levels of pretreatment low-density lipoprotein cholesterol than individuals with FH/M+ (t test for difference in means between FH/M- and FH/M+ groups &lt;0.0001); however, subjects with FH/M- and lp(a) score ≥1 had higher mean (SD) pretreatment low-density lipoprotein cholesterol levels (223.47 [50.40] mg/dL) compared with subjects with FH/M- and lp(a) score=0 (219.38 [54.54] mg/dL for), although not statistically significant. The adjustment of low-density lipoprotein cholesterol levels based on lp(a) concentration reduced from 68% to 42% the proportion of subjects with low-density lipoprotein cholesterol level ≥190 mg/dL (or from 68% to 50%, considering a more conservative formula). Conclusions Our study supports the importance of measuring lp(a) to perform the diagnosis of FH appropriately and to exclude that the observed phenotype is driven by elevated levels of lp(a) before performing the genetic test for FH
    corecore