Editorial

n/

Previsione della resistenza a fatica in saldature per punti attraverso modellazione solida

Nel presente lavoro vengono messi a confronto due metodi idonei per la verifica di giunzionisaldate per punti: il metodo del raggio di raccordo fittizio ed il metodo del gradiente implicito. Il primo imponeun raggio di raccordo diverso da zero al piede o alla radice del cordone di saldatura, il secondo, invece,considera più semplicemente la saldatura come un intaglio acuto. Il confronto è fatto sulla capacità di prevederel’affidabilità di giunti saldati per punti in acciaio aventi spessore variabile da 0.8 a 1.5 mm. Tali giunti sonosollecitati a taglio (giunti a semplice sovrapposizione) o a trazione (giunti a tazza). Infine, è discussa lacondizione di convergenza delle analisi numeriche necessarie, in entrambi i metodi, per il calcolo di una tensioneequivalente da porre a confronto direttamente con la di resistenza a fatica del materiale

Previsione della resistenza a fatica in saldature per punti attraverso modellazione solida

Nel presente lavoro vengono messi a confronto due metodi idonei per la verifica di giunzionisaldate per punti: il metodo del raggio di raccordo fittizio ed il metodo del gradiente implicito. Il primo imponeun raggio di raccordo diverso da zero al piede o alla radice del cordone di saldatura, il secondo, invece,considera più semplicemente la saldatura come un intaglio acuto. Il confronto è fatto sulla capacità di prevederel’affidabilità di giunti saldati per punti in acciaio aventi spessore variabile da 0.8 a 1.5 mm. Tali giunti sonosollecitati a taglio (giunti a semplice sovrapposizione) o a trazione (giunti a tazza). Infine, è discussa lacondizione di convergenza delle analisi numeriche necessarie, in entrambi i metodi, per il calcolo di una tensioneequivalente da porre a confronto direttamente con la di resistenza a fatica del materiale

The second generation of HIV-1 vertically exposed infants: A case series from the Italian Register for paediatric HIV infection

BACKGROUND: In the Highly Active Antiretroviral Therapy (HAART) era, the prognosis of children perinatally infected with HIV-1 has significantly improved, so the number of perinatally-infected females entering child-bearing age and experiencing motherhood is increasing. METHODS: A description of the medical history and pregnancy outcomes of women with perinatal acquired HIV-1 infection enrolled in the Italian Register for HIV infection in Children. RESULTS: Twenty-three women had 29 pregnancies. They had started an antiretroviral therapy at a median of 7.7 years (interquartile range, IQR 2.3 - 11.4), and had experienced a median of 4 therapeutic regimens (IQR 2–6). Twenty women (87%) had taken zidovudine (AZT) before pregnancy, in 14 cases as a starting monotherapy. In 21 pregnancies a protease inhibitor-based regimen was used. At delivery, the median of CD4+ T lymphocytes was 450/μL (IQR 275–522), and no viral load was detectable in 15 cases (reported in 21 pregnancies). Twenty-eight children were delivered through caesarean section (median gestational age: 38 weeks, IQR 36–38, median birth weight: 2550 grams, IQR 2270 – 3000). Intravenous AZT was administered during delivery in 26 cases. All children received oral AZT (median: 42 days, IQR 31 – 42), with no adverse events reported. No child acquired HIV-1 infection. CONCLUSIONS: Despite a long history of maternal infection, multiple antiretroviral regimens and, perhaps, the development of drug-resistant viruses, the risk of mother-to-child transmission does not seem to have increased among the second-generation of HIV-1 exposed infants

Covid-19 in children: Expressions of type i/ii/iii interferons, trim28, setdb1, and endogenous retroviruses in mild and severe cases

Children with the new coronavirus disease 2019 (COVID-19) have milder symptoms and a better prognosis than adult patients. Several investigations assessed type I, II, and III interferon (IFN) signatures in SARS-CoV-2 infected adults, however no data are available for pediatric patients. TRIM28 and SETDB1 regulate the transcription of multiple genes involved in the immune response as well as of human endogenous retroviruses (HERVs). Exogenous viral infections can trigger the activation of HERVs, which in turn can induce inflammatory and immune reactions. Despite the potential cross-talks between SARS-CoV-2 infection and TRIM28, SETDB1, and HERVs, information on their expressions in COVID-19 patients is lacking. We assessed, through a PCR real time Taqman amplification assay, the transcription levels of six IFN-I stimulated genes, IFN-II and three of its sensitive genes, three IFN-lIIs, as well as of TRIM28, SETDB1, pol genes of HERV-H, -K, and -W families, and of env genes of Syncytin (SYN)1, SYN2, and multiple sclerosis-associated retrovirus (MRSV) in peripheral blood from COVID-19 children and in control uninfected subjects. Higher expression levels of IFN-I and IFN-II inducible genes were observed in 36 COVID-19 children with mild or moderate disease as compared to uninfected controls, whereas their concentrations decreased in 17 children with severe disease and in 11 with multisystem inflammatory syndrome (MIS-C). Similar findings were found for the expression of TRIM-28, SETDB1, and every HERV gene. Positive correlations emerged between the transcriptional levels of type I and II IFNs, TRIM28, SETDB1, and HERVs in COVID-19 patients. IFN-III expressions were comparable in each group of subjects. This preserved induction of IFN-λs could contribute to the better control of the infection in children as compared to adults, in whom IFN-III deficiency has been reported. The upregulation of IFN-I, IFN-II, TRIM28, SETDB1, and HERVs in children with mild symptoms, their declines in severe cases or with MIS-C, and the positive correlations of their transcription in SARS-CoV-2-infected children suggest that they may play important roles in conditioning the evolution of the infection