Robot-assisted excision of urachal cyst: case report in a child

Background The urachus is an embryological structure of the urogenital sinus and allantoid that connects the allantois to the early bladder in fetal life and then remains as the median umbilical ligament connecting the umbilicus to the dome of the bladder. An early laparoscopic procedure could trigger a quiescent urachal remnant to become symptomatic, causing a lesion or infection either during carbon oxide contamination or insufflation or a periumbilical or suprapubic port placement. Case presentation A 15-year-old girl complaining of supra-pubic abdominal pain. About 2 months previously, she had undergone laparoscopic appendectomy for acute appendicitis, and early postoperative period was uneventful. She underwent a robotic-assisted excision of a urachal cyst. Conclusions It has been suggested that early laparoscopic procedures could trigger previously asymptomatic urachal remnants to become symptomatic. Robot-assisted excision of a urachal cyst is a safe, effective alternative to open surgery in children.

A new class of high-entropy M3B4 borides

A new class of high-entropy M3B4 borides of the Ta3B4-prototyped orthorhombic structure has been synthesized in the bulk form for the first time. Specimens with compositions of (V0.2Cr0.2Nb0.2Mo0.2Ta0.2)3B4 and (V0.2Cr0.2Nb0.2Ta0.2W0.2)3B4 were fabricated via reactive spark plasma sintering of high-energy-ball-milled elemental boron and metal precursors. The sintered specimens were ∼98.7% in relative densities with virtually no oxide contamination, albeit the presence of minor (4–5 vol%) secondary high-entropy M5B6 phases. Despite that Mo3B4 or W3B4 are not stable phase, 20% of Mo3B4 and W3B4 can be stabilized into the high-entropy M3B4 borides. Vickers hardness was measured to be 18.6 and 19.8 GPa at a standard load of 9.8 N. This work has further expanded the family of different structures of high-entropy ceramics reported to date.

Liquid-ammonia synthesis of microporous Mg3N2showing intense red-light emission

Magnesium nitride (Mg3N2) is preparedvialyotropic phases with liquid ammonia (lq-NH3). To avoid oxide contamination, the synthesis was performed in the absence of any oxygen source (e.g., solvents, starting materials and surfactants).

²¹⁰Pb-²²⁶Ra chronology reveals rapid growth rate of <i>Madrepora oculata</i> and <i>Lophelia pertusa</i> on world's largest cold-water coral reef

Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of two corals from the world's largest known cold-water coral reef, Røst Reef, north of the Arctic circle off Norway. Colonies of each of the two species that build the reef, Lophelia pertusa and Madrepora oculata, were collected alive at 350 m depth using a submersible. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and trace element compositions were studied. 210Pb and 226Ra differ in the way they are incorporated into coral skeletons. Hence, to assess growth rates, we considered the exponential decrease of initially incorporated 210Pb, as well as the increase in 210Pb from the decay of 226Ra and contamination with 210Pb associated with Mn-Fe coatings that we were unable to remove completely from the oldest parts of the skeletons. 226Ra activity was similar in both coral species, so, assuming constant uptake of 210Pb through time, we used the 210Pb-226Ra chronology to calculate growth rates. The 45.5 cm long branch of M. oculata was 31 yr with an average linear growth rate of 14.4 ± 1.1 mm yr−1 (2.6 polyps per year). Despite cleaning, a correction for Mn-Fe oxide contamination was required for the oldest part of the colony; this correction corroborated our radiocarbon date of 40 yr and a mean growth rate of 2 polyps yr−1. This rate is similar to the one obtained in aquarium experiments under optimal growth conditions. For the 80 cm-long L. pertusa colony, metal-oxide contamination remained in both the middle and basal part of the coral skeleton despite cleaning, inhibiting similar age and growth rate estimates. The youngest part of the colony was free of metal oxides and this 15 cm section had an estimated a growth rate of 8 mm yr−1, with high uncertainty (~1 polyp every two to three years). We are less certain of this 210Pb growth rate estimate which is within the lowermost ranges of previous growth rate estimates. We show that 210Pb-226Ra dating can be successfully applied to determine the age and growth rate of framework-forming cold-water corals if Mn-Fe oxide deposits can be removed. Where metal oxides can be removed, large M. oculata and L. pertusa skeletons provide archives for studies of intermediate water masses with an up to annual time resolution and spanning over many decades.