91 research outputs found

    Formation and dynamics of van der Waals molecules in buffer-gas traps

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    We show that weakly bound He-containing van der Waals molecules can be produced and magnetically trapped in buffer-gas cooling experiments, and provide a general model for the formation and dynamics of these molecules. Our analysis shows that, at typical experimental parameters, thermodynamics favors the formation of van der Waals complexes composed of a helium atom bound to most open-shell atoms and molecules, and that complex formation occurs quickly enough to ensure chemical equilibrium. For molecular pairs composed of a He atom and an S-state atom, the molecular spin is stable during formation, dissociation, and collisions, and thus these molecules can be magnetically trapped. Collisional spin relaxations are too slow to affect trap lifetimes. However, helium-3-containing complexes can change spin due to adiabatic crossings between trapped and untrapped Zeeman states, mediated by the anisotropic hyperfine interaction, causing trap loss. We provide a detailed model for Ag3He molecules, using ab initio calculation of Ag-He interaction potentials and spin interactions, quantum scattering theory, and direct Monte Carlo simulations to describe formation and spin relaxation in this system. The calculated rate of spin-change agrees quantitatively with experimental observations, providing indirect evidence for molecular formation in buffer-gas-cooled magnetic traps.Comment: 20 pages, 13 figure

    De novo unbalanced translocations have a complex history/aetiology

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    We investigated 52 cases of de novo unbalanced translocations, consisting in a terminally deleted or inverted-duplicated deleted (inv-dup del) 46th chromosome to which the distal portion of another chromosome or its opposite end was transposed. Array CGH, whole-genome sequencing, qPCR, FISH, and trio genotyping were applied. A biparental origin of the deletion and duplication was detected in 6 cases, whereas in 46, both imbalances have the same parental origin. Moreover, the duplicated region was of maternal origin in more than half of the cases, with 25% of them showing two maternal and one paternal haplotype. In all these cases, maternal age was increased. These findings indicate that the primary driver for the occurrence of the de novo unbalanced translocations is a maternal meiotic non-disjunction, followed by partial trisomy rescue of the supernumerary chromosome present in the trisomic zygote. In contrast, asymmetric breakage of a dicentric chromosome, originated either at the meiosis or postzygotically, in which the two resulting chromosomes, one being deleted and the other one inv-dup del, are repaired by telomere capture, appears at the basis of all inv-dup del translocations. Notably, this mechanism also fits with the origin of some simple translocations in which the duplicated region was of paternal origin. In all cases, the signature at the translocation junctions was that of non-homologous end joining (NHEJ) rather than non-allelic homologous recombination (NAHR). Our data imply that there is no risk of recurrence in the following pregnancies for any of the de novo unbalanced translocations we discuss here

    Haploinsufficiency for ANKRD11-flanking genes makes the difference between KBG and 16q24.3 microdeletion syndromes:12 new cases

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    16q24 deletion involving the ANKRD11 gene, ranging from 137 kb to 2 Mb, have been associated with a microdeletion syndrome characterized by variable cognitive impairment, autism spectrum disorder, facial dysmorphisms with dental anomalies, brain abnormalities essentially affecting the corpus callosum and short stature. On the other hand, patients carrying either deletions encompassing solely ANKRD11 or its loss-of-function variants were reported in association with the KBG syndrome, characterized by a very similar phenotype, including mild-to-moderate intellectual disability, short stature and macrodontia of upper incisors, with inter and intrafamilial variability. To assess whether the haploinsufficiency of ANKRD11-flanking genes, such as ZFPM1, CDH15 and ZNF778, contributed to either the severity of the neurological impairment or was associated with other clinical features, we collected 12 new cases with a 16q24.2q24.3 deletion (de novo in 11 cases), ranging from 343 kb to 2.3 Mb. In 11 of them, the deletion involved the ANKRD11 gene, whereas in 1 case only flanking genes upstream to it were deleted. By comparing the clinical and genetic features of our patients with those previously reported, we show that the severity of the neurological phenotype and the frequency of congenital heart defects characterize the deletions that, besides ANKRD11, contain ZFPM1, CDH15 and ZNF778 as well. Moreover, the presence of thrombocytopenia and astigmatism should be taken into account to distinguish between 16q24 microdeletion syndrome and KBG syndrome. The single patient not deleted for ANKRD11, whose phenotype is characterized by milder psychomotor delay, cardiac congenital malformation, thrombocytopenia and astigmatism, confirms all this dat

    Analisi dei tempi d\u2019attesa tra le varie fasi di gestione dei carcinomi mammari screening-detected a Trieste nel biennio 2013-2014: come si pu\uf2 migliorare?

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    Gli indicatori relativi ai tempi di attesa sono difficili da rispettare, come recentemente evidenziato al XIII Convegno ONS 2015 . Per questo motivo \ue8 fondamentale identificare in quale momento della gestione dei carcinomi screening-detected si concentrino i ritardi e stabilirne le cause (se attribuibili alla paziente o all\u2019organizzazione del programma o intrinseci al tipo di lesione) cos\uec da proporre mirate modifiche migliorative. Metodi: L\u2019analisi riguarda 146 carcinomi screening-detected consecutivi (biennio 2013-2014). Sono stati misurati i tempi tra le varie fasi diagnostiche (Mammografia di I\ub0 livello, Richiamo II\ub0 livello, I\ub0 approfondimento cito/microistologico, Comunicazione diagnosi) e i tempi chirurgici (Visita chirurgica, Intervento chirurgico, Referto istologico con marcatori biologici, Visita oncologica). Per ogni fase sono stati calcolati i tempi medi/mediani rappresentati tramite box plot e giustificati gli outliers.Risultati: La latenza nella presa in carico chirurgica \ue8 legato alla complessit\ue0 degli esami preoperatori (3) (tempo mediano tra richiamo al II\ub0 livello ed intervento: 53 giorni (se unico esame pre-operatorio) vs 73 (se pi\uf9 di un esame pre-operatorio, p<0.0001), mentre rispetto ad un recente studio (4) il tempo mediano tra visita chirurgica e intervento non \ue8 aumentato per i casi con necessit\ue0 di RM (28 vs 26 giorni, p=0.13), perch\ue9 gi\ue0 programmata in fase preoperatoria. Per i casi con mastectomia sempre con ricostruzione, si registra un tempo medio dalla visita chirurgica all\u2019intervento di 7 giorni superiore rispetto alle quadrantectomie. Ulteriore criticit\ue0 \ue8 il tempo mediano tra intervento e visita oncologica (44 giorni), attribuibile in parte ad un \u201critardo\u201d nella disponibilit\ue0 dei marcatori biomolecolari (soprattutto HER2/FISH) ed in parte a rinvii dell\u2019appuntamento da parte della paziente stessa Conclusioni: Soltanto un attento monitoraggio del turnaround time dell\u2019intero percorso delle pazienti con carcinoma screening detected consente l\u2019identificazione dei punti di debolezza su cui intervenire efficacemente per garantire il rispetto degli indicatori
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