Two-Channel Indirect-Gap Photoluminescence and Competition between the Conduction Band Valleys in Few-Layer MoS2.

MoS2 is a two-dimensional layered transition metal dichalcogenide with unique electronic and optical properties. The fabrication of ultrathin MoS2 is vitally important, since interlayer interactions in its ultrathin varieties will become thickness-dependent, providing thickness-governed tunability and diverse applications of those properties. Unlike with a number of studies that have reported detailed information on direct bandgap emission from MoS2 monolayers, reliable experimental evidence for thickness-induced evolution or transformation of the indirect bandgap remains scarce. Here, the sulfurization of MoO3 thin films with nominal thicknesses of 30 nm, 5 nm and 3 nm was performed. All sulfurized samples were examined at room temperature with spectroscopic ellipsometry and photoluminescence spectroscopy to obtain information about their dielectric function and edge emission spectra. This investigation unveiled an indirect-to-indirect crossover between the transitions, associated with two different Λ and K valleys of the MoS2 conduction band, by thinning its thickness down to a few layers.

Childbirth Care among SARS-CoV-2 Positive Women in Italy.

The new coronavirus emergency spread to Italy when little was known about the infection's impact on mothers and newborns. This study aims to describe the extent to which clinical practice has protected childbirth physiology and preserved the mother-child bond during the first wave of the pandemic in Italy. A national population-based prospective cohort study was performed enrolling women with confirmed SARS-CoV-2 infection admitted for childbirth to any Italian hospital from 25 February to 31 July 2020. All cases were prospectively notified, and information on peripartum care (mother-newborn separation, skin-to-skin contact, breastfeeding, and rooming-in) and maternal and perinatal outcomes were collected in a structured form and entered in a web-based secure system. The paper describes a cohort of 525 SARS-CoV-2 positive women who gave birth. At hospital admission, 44.8% of the cohort was asymptomatic. At delivery, 51.9% of the mothers had a birth support person in the delivery room; the average caesarean section rate of 33.7% remained stable compared to the national figure. On average, 39.0% of mothers were separated from their newborns at birth, 26.6% practised skin-to-skin, 72.1% roomed in with their babies, and 79.6% of the infants received their mother's milk. The infants separated and not separated from their SARS-CoV-2 positive mothers both had good outcomes. At the beginning of the pandemic, childbirth raised awareness and concern due to limited available evidence and led to "better safe than sorry" care choices. An improvement of the peripartum care indicators was observed over time.

Near-field enhancement in oxidized close gap aluminum dimers.

Aluminum bowtie nanoantennas represent a possibility to confine and enhance electromagnetic (EM) field at optical frequencies in subwavelength regions by using an abundant and inexpensive metal. The native oxidation process of this metal is often viewed as a limitation for its application in plasmonics. Here, we show that in close gap configurations, the high refractive index of the native aluminum oxide helps in squeezing the plasmonic mode in extremely reduced size volumes, providing a higher EM near-field confinement and enhancement in the bowtie antenna gaps than achieved in the pure aluminum counterpart. Hence, the study provides new perspectives in the use of such a plasmonic antenna geometry within this aluminum system, which can be useful for improving plasmonics-enabled effects such as surface-enhanced Raman scattering- and light-matter interaction in strong coupling regime.

Chronic exposure to high doses of selenium in the first trimester of pregnancy: Case report and brief literature review.

BACKGROUND: Obstetricians usually prescribe supplements during pregnancy without actual indication. The use of selenium during pregnancy has increased, due to its function in several antioxidant mechanisms. CASE: A pregnant woman received 200,000 micrograms (µg) per day of a selenium galenic formulation, since gestational week (g.w.) 7 to 12, due to a prescription error. The patient experienced nausea, vomiting, hand and foot paresthesia, followed by fatigue, loss of fingernails and hair. The woman was referred to our Fetal and Maternal Medicine Unit for surveillance. The mother's blood selenium levels went back to normal 13 weeks after arrest and the baby was born at term, without complications. Clinical evaluation and imaging studies were normal at one month of age. CONCLUSION: This is the first case of severe chronic selenium intoxication during the first trimester of pregnancy. In the present case, no consequences of congenital defects or pregnancy complications occurred. However, since vitamins, minerals, and food supplements may be harmful and prescription errors occur, obstetricians should avoid prescribing supplements in the absence of maternal deficiency.