19 research outputs found
Ammonia, carbon dioxide and the non-detection of the 2152 cm CO band
CO is one of the most abundant ice components on interstellar dust grains.
When it is mixed with amorphous solid water (ASW) or located on its surface, an
absorption band of CO at 2152 cm is always present in laboratory
measurements. This spectral feature is attributed to the interaction of CO with
dangling-OH bonds (dOH) in ASW. However, this band is absent in observational
spectra of interstellar ices. This raises the question whether CO forms a
relatively pure layer on top of ASW or is in close contact with ASW, but not
via dangling bonds. We aim to determine whether the incorporation of NH or
CO into ASW blocks the dOH and therefore reduces the 2152 cm band.
We performed laboratory experiments to simulate the layered structure of the
ice mantle, that is, we grew CO ice on top of 1) pure ASW, 2)
NH:HO=10:100 mixed ice, and 3) CO:HO=20:100 mixed ice. Infrared
spectra were measured to quantify the strength of the 2152 cm band. In
addition, a second set of experiments were performed to determine how the
incorporation of NH into ASW affects the dOH band. We found that annealing
the ice reduces the 2152 cm band and that NH blocks the dOH on ASW
surface and therefore reduces the 2152 cm band more effectively than
CO. We suggest that this difference between NH and CO can be
ascribed to the polarity of the guest molecule (NH is a polar species,
whereas CO is apolar). The polarity implies that the formation of an H-bond
between the N atom of ammonia and the dOH is a barrier-less reaction. We also
determined the pore surface area of the ice mixtures as a function of the
annealing temperature, and found that the nondetection of 2152 cm band
does not necessarily exclude the possibility of a porous ice mantle.Comment: 10 pages, 10 figure
Prenatal diagnosis of transient abnormal myelopoyesis in three fetuses with Down syndrome: heterogeneous ultrasonographic findings and outcomes
Transient abnormal myelopoyesis (TAM) is diagnosed in approximately 10% of babies with Down syndrome (DS), progressing to life-threatening illness in 20% of them. We describe three cases of TAM characterized by heterogeneous ultrasonographic findings and outcomes. The first case was a 27-year-old woman at 32 weeks and 5 days with severe fetal hepatosplenomegaly: liver longitudinal diameter of 78âmm, >2SD (1) and spleen longitudinal diameter of 60âmm, >2SD (2) (Figure 1)
Holocene Deformations at the Po PlainâSouthern Alps Transition (Lake Maggiore, Italy): Inferences on Glacially vs. Tectonic-Induced Origin
The investigation of deformations in Quaternary deposits holds primary importance in understanding recent geological history and natural hazards in highly populated areas, such as the Po Plain. While civil excavations and trenches possess the potential to be pivotal in identifying and characterizing these deformations, they often remain underused due to the stringent regulation framework and timetables governing civil construction works. In this study, we demonstrate how digital photogrammetry and digital outcrop modelling (DOM) are useful techniques for obtaining a permanent digital representation of a trench situated in Castelletto Ticino (Po PlainâSouthern Alps transition). This trench exhibits Holocene deformational structures: (i) an overall tilting of sedimentary deposits towards the SW; (ii) folds with a NEâSW trend; (iii) slumping and other soft-sediment deformations structures; and (iv) reverse faults with NEâSW and NWâSE directions. Using radiocarbon and archeological dating, we are able to confidently constrain the age of these deformations to between 8760 and 400 years BC, suggesting recent tectonic activity related to buried thrust faults
Literature Review and an Italian Hospital Experience about Post-Natal CMV Infection Acquired by Breast-Feeding in Very Low and/or Extremely Low Birth Weight Infants
Breastfeeding is recommended for all neonates due to a known variety of beneficial effects, but infants can be infected by cell-associated bacteria and viruses from breast milk, such as cytomegalovirus (CMV). The majority of CMV-seropositive breastfeeding women have a viral, self-restricted reactivation, can shed the virus in the milk for about 12 weeks after delivery, and can transmit the infection to their offspring. Post-natal CMV-infected term infants are mainly asymptomatic, while very low birth weight (VLBW, <1500 g) and extremely low birth weight (ELBW, <1000 g) infants may present with severe disease, short-term sequelae ranging from abnormalities in laboratory indexes to sepsis-like syndrome, and long-term sequelae such as developmental problems. Thus, the use of thermally treated maternal milk for VLBW/ELBW infants may be indicated to prevent/reduce the risk of CMV transmission. Different techniques, with varying efficacy in eradicating CMV and maintaining the activity of biological compounds in milk are available: long/short pasteurization, freeze-thawing, the use of microwaves, and ultraviolet-C irradiation. In our NICU, the use of maternal raw milk is always strongly recommended for term/preterm infants, but to reduce risk of CMV transmission, freeze-thawing motherâs own milk is used in neonates with GA ⤠30 weeks or/and weight ⤠1000 g, usually regardless of serological maternal condition, as CMV screening is not routinely offered to pregnant women and the milk of seroimmune mothers is not evaluated for CMV reactivation, as its rate is similar to seroprevalence. Over the last 4 years, we had 10 VLBW/ELBW newborns in our NICU with late-onset sepsis and negative cultures. In these cases, the research of CMV DNA in neonatal urine or saliva, for the diagnosis of post-natal symptomatic infection (once congenital transmission has been excluded) may be useful and not invasive. The take-home message we would like to share is that acquired CMV infection should be considered in VLBW/ELBW infants breastfed by seropositive mothers and presenting severe symptomsâparticularly sepsis with negative cultures. This could allow pediatricians to make better-quality diagnoses, perform supportive therapy, provide antiviral treatment if needed, or establish a âpre-emptiveâ therapy for these high-risk neonates
Neurodevelopmental outcome of Italian preterm ELBW infants: an eleven years single center cohort
Abstract Background Preterm extremely low birth weight infants (ELBWi) are known to be at greater risk of developing neuropsychiatric diseases. Identifying early predictors of outcome is essential to refer patients for early intervention. Few studies have investigated neurodevelopmental outcomes in Italian ELBWi. This study aims to describe neurodevelopmental outcome at 24 months of corrected age in an eleven-year single-center cohort of Italian ELBWi and to identify early risk factors for adverse neurodevelopmental outcomes. Methods All infants born with birth weightâ<â1000 g and admitted to the Neonatal Intensive Care Unit of the âFondazione IRCCS Policlinico San Matteoâ hospital in Pavia, Italy, from Jan 1, 2005 to Dec 31, 2015 were eligible for inclusion. At 24 months, Griffithsâ Mental Developmental Scales Extended Revised (GMDS-ER) were administered. Neurodevelopmental outcome was classified as: normal, minor sequelae (minor neurological signs, General Quotient between 76 and 87), major sequelae (cerebral palsy; General Quotientââ¤â75; severe sensory impairment). Univariate and multivariate multinomial logistic regression models were performed to analyze the correlation between neonatal variables and neurodevelopmental outcome. Results 176 ELBWi were enrolled (mean gestational age 26.52 weeks sd2.23; mean birthweight 777.45 g sd142.89). 67% showed a normal outcome at 24 months, 17% minor sequelae and 16% major sequelae (4.6% cerebral palsy on overall sample). The most frequent major sequela was cognitive impairment (8.52%). In the entire sample the median score on the Hearing-Speech subscale was lower than the median scores recorded on the other subscales and showed a significantly weaker correlation to each of the other subscales of the GMDS-ER. Severely abnormal cUS findings (RRR 10.22 p 0.043) and bronchopulmonary dysplasia (RRR 4.36 p 0.008) were independent risk factors for major sequelae and bronchopulmonary dysplasia for minor sequelae (RRR 3.00 p 0.018) on multivariate multinomial logistic regression. Conclusions This study showed an improvement in ELBWI survival rate without neurodevelopmental impairment at 24 months compared to previously reported international cohorts. Cognitive impairment was the most frequent major sequela. Median scores on GMDS-ER showed a peculiar developmental profile characterized by a selective deficit in the language domain. Severely abnormal cUS findings and bronchopulmonary dysplasia were confirmed as independent risk factors for major sequelae
BNP concentrations and cardiovascular adaptation in preterm and fullterm newborn infants
To evaluate and compare cardiovascular adaptation of 36 preterm and 34 fullterm newborns, we analyzed BNP concentration and echocardiographic parameters at day 3 of life and at day 28 (+/- 2). On day 3 BNP concentrations (pg/ml) resulted higher in PDA preterm group (n = 11; 125, IQR 56.1-301) than preterm without PDA (n = 25; 25.5 IQR 10.9-49; p<0.001) than fullterms (n = 34; 55.1 IQR 23.6-82.7; p = 0.013). No difference resulted in all groups at 28 days (respectively: 12.7 IQR 4.9-23.8:15.6 IQR 10-22; 8.9 IQR 5.6-20.6). Because of the newborns' growth, all echocardiographic parameters increased with linear relationship with body weight. On day 3 BNP concentration and echocardiographic parameters were not correlated besides LA/AO in preterms with PDA (p = 0.0015). On day 28, BNP was significantly correlated with mVTl (p = 0.019), M (p = 0.007) and LA (p = 0.005) in fullterms and only with LA (p = 0.007) in preterms.
In conclusion, BNP concentrations and echocardiographic measures confirm that preterm, and fullterm newborns conduct themselves in a similar manner during the transition from foetal to post-natal circulation, reaching low levels at a month of life. The presence of PDA during first days of life has no significant impact in this adaptation. LA is the echocardiographic parameter mostly related to BNP concentration in the newborns. (C) 2010 Elsevier Ireland Ltd. All rights reserved