153 research outputs found
The role of fetal, infant, and childhood nutrition in the timing of sexual maturation
Puberty is a crucial developmental stage in the life span, necessary to achieve reproductive and somatic maturity. Timing of puberty is modulated by and responds to central neurotransmitters, hormones, and environmental factors leading to hypothalamic-pituitary-gonadal axis maturation. The connection between hormones and nutrition during critical periods of growth, like fetal life or infancy, is fundamental for metabolic adaptation response and pubertal development control and prediction. Since birth weight is an important indicator of growth estimation during fetal life, restricted prenatal growth, such as intrauterine growth restriction (IUGR) and small for gestational age (SGA), may impact endocrine system, affecting pubertal development. Successively, lactation along with early life optimal nutrition during infancy and childhood may be important in order to set up timing of sexual maturation and provide successful reproduction at a later time. Sexual maturation and healthy growth are also influenced by nutrition requirements and diet composition. Early nutritional surveillance and monitoring of pubertal development is recommended in all children, particularly in those at risk, such as the ones born SGA and/or IUGR, as well as in the case of sudden weight gain during infancy. Adequate macro and micronutrient intake is essential for healthy growth and sexual maturity
Personalized treatment planning in eye brachytherapy for ocular melanoma: Dosimetric analysis on ophthalmic structure at risk
Purpose: To evaluate the impact on dose distribution to eye organs-at-risk (eOARs) of a computed tomography (CT)-based treatment planning in eye plaque brachytherapy (EPB) treatment. Methods: We analyzed 19 ocular melanoma patients treated with ruthenium-106 plaques to a total dose of 100 Gy to tumor apex using conventional central-axis-point dose calculation. Treatments were re-planned using the Plaque Simulator (PS) software implementing two different strategies: a personalized CT-eye-model (CT-PS) and a standard-eye-model (SEM-PS) defined by Collaborative Ocular Melanoma Study. Dice coefficient and Hausdorff distance evaluated the concordance between eye-bulb-models. Mean doses (Dmean) to tumor and eOARs were extracted from Dose-Volume-Histograms and Retinal-Dose-Area-Histogram. Differences between planning approaches were tested by Wilcoxon signed-rank test. Results: In the analyzed cohort, 8 patients (42%) had posterior tumor location, 8 (42%) anterior, and 3 (16%) equatorial. The SEM did not accurately described the real CT eye-bulb geometry (median Hausdorff distance 0.8 mm, range: (0.4–1.3) mm). Significant differences in fovea and macula Dmean values were found (p = 0.04) between CT-PS and SEM-PS schemes. No significant dosimetric differences were found for tumor and other eOARs. The planning scheme particularly affects the OARs closest to the tumor with a general tendency of SEM-PS to overestimate the doses to the OARs closest to the tumor. Conclusion: The dosimetric accuracy achievable with CT-PS EPB treatment planning may help to identify ocular melanoma patients who could benefit the most from a personalized eye dosimetry for an optimal outcome in terms of tumor coverage and eOARs sparing. Further research and larger studies are underway
Early Life Microbiota Colonization at Six Months of Age: A Transitional Time Point
Background: Early life gut microbiota is involved in several biological processes, particularly metabolism, immunity, and cognitive neurodevelopment. Perturbation in the infant's gut microbiota increases the risk for diseases in early and later life, highlighting the importance of understanding the connections between perinatal factors with early life microbial composition. The present research paper is aimed at exploring the prenatal and postnatal factors influencing the infant gut microbiota composition at six months of age.
Methods: Gut microbiota of infants enrolled in the longitudinal, prospective, observational study "A.MA.MI" (Alimentazione MAmma e bambino nei primi MIlle giorni) was analyzed. We collected and analyzed 61 fecal samples at baseline (meconium, T0); at six months of age (T2), we collected and analyzed 53 fecal samples. Samples were grouped based on maternal and gestational weight factors, type of delivery, type of feeding, time of weaning, and presence/absence of older siblings. Alpha and beta diversities were evaluated to describe microbiota composition. Multivariate analyses were performed to understand the impact of the aforementioned factors on the infant's microbiota composition at six months of age.
Results: Different clustering hypotheses have been tested to evaluate the impact of known metadata factors on the infant microbiota. Neither maternal body mass index nor gestational weight gain was able to determine significant differences in infant microbiota composition six months of age. Concerning the type of feeding, we observed a low alpha diversity in exclusive breastfed infants; conversely, non-exclusively breastfed infants reported an overgrowth of Ruminococcaceae and Flavonifractor. Furthermore, we did not find any statistically significant difference resulting from an early introduction of solid foods (before 4 months of age). Lastly, our sample showed a higher abundance of clostridial patterns in firstborn babies when compared to infants with older siblings in the family.
Conclusion: Our findings showed that, at this stage of life, there is not a single factor able to affect in a distinct way the infants' gut microbiota development. Rather, there seems to be a complex multifactorial interaction between maternal and neonatal factors determining a unique microbial niche in the gastrointestinal tract
Prenatal and postnatal determinants in shaping offspring's microbiome in the first 1000 days: Study protocol and preliminary results at one month of life
Background: Fetal programming during in utero life defines the set point of physiological and metabolic responses that lead into adulthood; events happening in "the first 1,000 days" (from conception to 2-years of age), play a role in the development of non-communicable diseases (NCDs). The infant gut microbiome is a highly dynamic organ, which is sensitive to maternal and environmental factors and is one of the elements driving intergenerational NCDs' transmission. The A.MA.MI (Alimentazione MAmma e bambino nei primi MIlle giorni) project aims at investigating the correlation between several factors, from conception to the first year of life, and infant gut microbiome composition. We described the study design of the A.MA.MI study and presented some preliminary results. Methods: A.MA.MI is a longitudinal, prospective, observational study conducted on a group of mother-infant pairs (n = 60) attending the Neonatal Unit, Fondazione IRCCS Policlinico San Matteo, Pavia (Italy). The study was planned to provide data collected at T0, T1, T2 and T3, respectively before discharge, 1,6 and 12 months after birth. Maternal and infant anthropometric measurements were assessed at each time. Other variables evaluated were: Pre-pregnancy/gestational weight status (T0), maternal dietary habits/physical activity (T1-T3); infant medical history, type of feeding, antibiotics/probiotics/supplements use, environment exposures (e.g cigarette smoking, pets, environmental temperature) (T1-T3). Infant stool samples were planned to be collected at each time and analyzed using metagenomics 16S ribosomal RNA gene sequence-based methods. Results: Birth mode (cesarean section vs. vaginal delivery) and maternal pre pregnancy BMI (BMI < 25 Kg/m2 vs. BMI ≥ 25 Kg/m2), significant differences were found at genera and species levels (T0). Concerning type of feeding (breastfed vs. formula-fed), gut microbiota composition differed significantly at genus and species level (T1). Conclusion: These preliminary and explorative results confirmed that pre-pregnancy, mode of delivery and infant factors likely impact infant microbiota composition at different levels. Trial registration: ClinicalTrials.gov identifier: NCT04122612
Attempts to measure the magnetic field of the pulsating B star Eridani
We report on attempts to measure the magnetic field of the pulsating B star
Eridani with the Musicos spectropolarimeter attached to the 2m telescope
at the Pic du Midi, France. This object is one of the most extensively studied
stars for pulsation modes, and the existence of a magnetic field was suggested
from the inequality of the frequency separations of a triplet in the stars'
oscillation spectrum. We show that the inferred 5-10 kG field was not present
during our observations, which cover about one year. We discuss the influence
of the strong pulsations on the analysis of the magnetic field strength and set
an upper limit to the effective longitudinal field strength and to the field
strength for a dipolar configuration. We also find that the observed wind line
variability is caused by the pulsations.Comment: 8 pages, 7 figures, accepted by A&
Exploring Holographic General Gauge Mediation
We study models of gauge mediation with strongly coupled hidden sectors,
employing a hard wall background as an holographic dual description. The
structure of the soft spectrum depends crucially on the boundary conditions one
imposes on bulk fields at the IR wall. Generically, vector and fermion
correlators have poles at zero momentum, leading to gauge mediation by massive
vector messengers and/or generating Dirac gaugino masses. Instead, non-generic
choices of boundary conditions let one cover all of GGM parameter space.
Enriching the background with R-symmetry breaking scalars, the SSM soft term
structure becomes more constrained and similar to previously studied top-down
models, while retaining the more analytic control the present bottom-up
approach offers.Comment: 28 pages, 4 figures; v2: typos corrected and refs adde
Effects of ocean acidification on invertebrate settlement at volcanic CO<inf>2</inf> vents
We present the first study of the effects of ocean acidification on settlement of benthic invertebrates and microfauna. Artificial collectors were placed for 1 month along pH gradients at CO2 vents off Ischia (Tyrrhenian Sea, Italy). Seventy-nine taxa were identified from six main taxonomic groups (foraminiferans, nematodes, polychaetes, molluscs, crustaceans and chaetognaths). Calcareous foraminiferans, serpulid polychaetes, gastropods and bivalves showed highly significant reductions in recruitment to the collectors as pCO2 rose from normal (336-341 ppm, pH 8.09-8.15) to high levels (886-5,148 ppm) causing acidified conditions near the vents (pH 7.08-7.79). Only the syllid polychaete Syllis prolifera had higher abundances at the most acidified station, although a wide range of polychaetes and small crustaceans was able to settle and survive under these conditions. A few taxa (Amphiglena mediterranea, Leptochelia dubia, Caprella acanthifera) were particularly abundant at stations acidified by intermediate amounts of CO2 (pH 7. 41-7.99). These results show that increased levels of CO2 can profoundly affect the settlement of a wide range of benthic organisms. © 2010 Springer-Verlag
Holographic Correlators for General Gauge Mediation
We use holographic techniques to compute two-point functions of operators
belonging to a conserved current supermultiplet in theories which break
supersymmetry at strong coupling. These are the relevant quantities one has to
compute in models of gauge mediation to determine the soft spectrum in
supersymmetric extensions of the Standard Model (SSM). Such holographic
approach can be used for diverse gravitational backgrounds, but here we focus,
for definiteness, on asymptotically AdS backgrounds. After presenting the
general framework, we apply our formulas to two explicit examples which differ
by the nature of the SSM gauginos, which have Dirac or Majorana masses,
corresponding to models that respectively preserve or break R-symmetry.Comment: 30 pages, 6 figures. v3: clarifications added, typos corrected, refs
added, one figure improve
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