689 research outputs found
Sloshing dynamics estimation for liquid-filled containers performing 3-dimensional motions: modeling and experimental validation
Many industrial applications require the displacement of liquid-filled containers on planar paths (namely, paths on a horizontal plane), by means of linear transport systems or serial robots. The movement of the liquid inside the container, known as sloshing, is usually undesired, thus there is the necessity to keep under control the peaks that the liquid free-surface exhibits during motion. This paper aims at validating a model for estimating the liquid sloshing height, taking into account 2-dimensional motions of a cylindrical container occurring on a horizontal plane, with accelerations up to 9.5 m/s2. This model can be exploited for assessment or optimization purposes. Experiments performed with a robot following three paths, each one of them with different motion profiles, are described. Comparisons between experimental results and model predictions are provided and discussed. Finally, the previous formulation is extended in order to take into account the addition of a vertical acceleration, up to 5 m/s2. The resulting 3-dimensional motions are experimentally validated to prove the effectiveness of the extended technique
Radiochemical separation of 7Be from the cooling water of the neutron spallation source SINQ at PSI
7Be is a key radionuclide for investigation of several astrophysical processes and phenomena. In addition, it is used as a tracer in wear measurements. It is produced in considerable amounts in the cooling water (D2O) of the Spallation Induced Neutron Source (SINQ) facility at PSI by spallation reactions on 16O with the generated fast neutrons. A shielded ion-exchange filter containing 100 mL of the mixed-bed ion exchanger LEWATIT was installed as a bypass for the cooling water into the cooling loop of SINQ for three months. The collected activity of 7Be was in the range of several hundred GBq. Further, the 7Be was separated and purified in a hot-cell remotely-controlled using a separation system installed. With the exception of 10Be, radioactive byproducts can be neglected, so that this cooling water could serve as an ideal source for highly active 7Be-samples. The facility is capable of producing 7Be with activities up to 1 TBq per year. The 7Be sample preparation is described in detail and the possible uses are discussed. In particular some preliminary results of 7Be ion beam production are presente
Labeling male anorectal malformations: objective evaluation of radiologic imaging before surgery
PurposeProne cross-table lateral x-ray (CTLxR) and colostogram aid surgical planning for anorectal malformations (ARMs) without perineal fistulas. We suggest objective imaging tools to classify ARMs.MethodsThree observers prospectively evaluated CTLxR and colostograms of male ARM patients (2012–2022) without perineal fistulas. The level of the rectal pouch was estimated with pubococcygeal (PC) and ischiatic (I) lines. On CTLxR, we described the “pigeon sign”, defined as the rectal pouch ending with a beak-like image, suspicious for a rectourinary fistula. ARM was defined as rectobulbar when the rectal pouch was below the I line, rectoprostatic when between PC and I lines, and rectovesical when above the PC line. Concordance was assessed with Fleiss' kappa. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the “pigeon sign” were calculated.ResultsThirteen patients were included in this study. The interobserver agreement on CTLxR was 69.2% (k = 0.54) on pouch ending, 84.6% (k = 0.69) on the “pigeon sign”, and 76.9% (k = 0.69) on diagnosis; concordance between observers and intraoperative diagnosis was 66.6% (k = 0.56). The “pigeon sign” had 75% sensitivity, 100% specificity, 100% PPV, and 50% NPV. The interobserver agreement on colostograms was 84.6% (k = 0.77) on pouch ending and 89.7% (k = 0.86) on diagnosis; concordance between observers and intraoperative diagnosis was 92.3% (k = 0.90).ConclusionPC and I lines and the “pigeon sign” are useful tools in examining CTLxR and colostograms. Adequate CTLxR interpretation may modify surgical strategy
Measurement of 1323 and 1487 keV resonances in 15N({\alpha}, {\gamma})19F with the recoil separator ERNA
The origin of fluorine is a widely debated issue. Nevertheless, the
^{15}N({\alpha},{\gamma})^{19}F reaction is a common feature among the various
production channels so far proposed. Its reaction rate at relevant temperatures
is determined by a number of narrow resonances together with the DC component
and the tails of the two broad resonances at E_{c.m.} = 1323 and 1487 keV.
Measurement through the direct detection of the 19F recoil ions with the
European Recoil separator for Nuclear Astrophysics (ERNA) were performed. The
reaction was initiated by a 15N beam impinging onto a 4He windowless gas
target. The observed yield of the resonances at Ec.m. = 1323 and 1487 keV is
used to determine their widths in the {\alpha} and {\gamma} channels. We show
that a direct measurement of the cross section of the
^{15}N({\alpha},{\gamma})^{19}F reaction can be successfully obtained with the
Recoil Separator ERNA, and the widths {\Gamma}_{\gamma} and {\Gamma}_{\alpha}
of the two broad resonances have been determined. While a fair agreement is
found with earlier determination of the widths of the 1487 keV resonance, a
significant difference is found for the 1323 keV resonance {\Gamma}_{\alpha} .
The revision of the widths of the two more relevant broad resonances in the
15N({\alpha},{\gamma})19F reaction presented in this work is the first step
toward a more firm determination of the reaction rate. At present, the residual
uncertainty at the temperatures of the ^{19}F stellar nucleosynthesis is
dominated by the uncertainties affecting the Direct Capture component and the
364 keV narrow resonance, both so far investigated only through indirect
experiments.Comment: 8 pages, 11 figures. Accepted for publication in PR
Role of neuronal and non-neuronal acetylcholine signaling in Drosophila humoral immunity
Acetylcholine (ACh) is one the major neurotransmitters in insects, whose role in mediating synaptic interactions between neurons in the central nervous system is well characterized. It also plays largely unexplored regulatory functions in non-neuronal tissues. Here we demonstrate that ACh signaling is involved in the modulation of the innate immune response of Drosophila melanogaster. Knockdown of ACh synthesis or ACh vesicular transport in neurons reduced the activation of drosomycin (drs), a gene encoding an antimicrobial peptide, in adult flies infected with a Gram-positive bacterium. drs transcription was similarly affected in Drosophila α7 nicotinic acetylcholine receptor, nAChRalpha7 (Dα7) mutants, as well as in flies expressing in the nervous system a dominant negative form (Dα7DN) of this specific receptor subunit. Interestingly, Dα7DN elicited a comparable response when it was expressed in non-neuronal tissues and even when it was specifically produced in the hemocytes. Consistently, full activation of the drs gene required Dα7 expression in these cells. Moreover, knockdown of ACh synthesis in non-neuronal cells affected drs expression. Overall, these findings uncover neural and non-neural cholinergic signals that modulate insect immune defenses and shed light on the role of hemocytes in the regulation of the humoral immune response
Acute heart failure in an adult with unrecognized congenital heart disease
We report a case of 46 year-old man, admitted to our Department for a possible massive pulmonary embolism. Instead, diagnosis of Tetralogy of Fallot was established by echocardiography and cardiac catetherization
Natural SINEUP RNAs in Autism Spectrum Disorders: RAB11B-AS1 Dysregulation in a Neuronal CHD8 Suppression Model Leads to RAB11B Protein Increase
CHD8 represents one of the highest confidence genetic risk factors implied in Autism Spectrum Disorders, with most mutations leading to CHD8 haploinsufficiency and the insurgence of specific phenotypes, such as macrocephaly, facial dysmorphisms, intellectual disability, and gastrointestinal complaints. While extensive studies have been conducted on the possible consequences of CHD8 suppression and protein coding RNAs dysregulation during neuronal development, the effects of transcriptional changes of long non-coding RNAs (lncRNAs) remain unclear. In this study, we focused on a peculiar class of natural antisense lncRNAs, SINEUPs, that enhance translation of a target mRNA through the activity of two RNA domains, an embedded transposable element sequence and an antisense region. By looking at dysregulated transcripts following CHD8 knock down (KD), we first identified RAB11B-AS1 as a potential SINEUP RNA for its domain configuration. Then we demonstrated that such lncRNA is able to increase endogenous RAB11B protein amounts without affecting its transcriptional levels. RAB11B has a pivotal role in vesicular trafficking, and mutations on this gene correlate with intellectual disability and microcephaly. Thus, our study discloses an additional layer of molecular regulation which is altered by CHD8 suppression. This represents the first experimental confirmation that naturally occurring SINEUP could be involved in ASD pathogenesis and underscores the importance of dysregulation of functional lncRNAs in neurodevelopment
Toward a reassessment of the 19F(p, α0)16O reaction rate at astrophysical temperatures
AbstractThe 19F(p, α0)16O reaction at low energies plays an important role in fundamental physics. In particular in nuclear astrophysics it represents, together with the 19F(p, γ)20Ne reaction, the crossing point between the CNO and the NeNa cycles in stars. Further, in hydrogen-rich stellar environments, it is the most important fluorine destruction channel. In this paper we report new measurements on the 19F(p, α0)16O reaction at deeply sub-Coulomb energies (0.2–0.6 MeV), a region where, despite the key role of this reaction, very few and old data are reported. The deduced astrophysical S-factor is ≈1.5–2 times larger than currently adopted extrapolations with possibly important astrophysical consequences
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