The electronic band structures of Be and BeO have been measured by transmission electron momentum spectroscopy (EMS). The low atomic number of beryllium and the use of ultrathin solid films in these ...experiments reduce the probability of electron multiple scattering within the sample, resulting in very clean ‘benchmark’ measurements for the EMS technique. Experimental data are compared to tight-binding (LCAO) electronic structure calculations using Hartree–Fock , and local density (LDA-VWN), gradient corrected (PBE) and hybrid (PBE0) density functional theory. Overall, DFT calculations reproduce the EMS data for metallic Be reasonably well. PBE predictions for the valence bandwidth of Be are in excellent agreement with EMS data, provided the calculations employ a large basis set augmented with diffuse functions. For BeO, PBE calculations using a moderately sized basis set are in reasonable agreement with experiment, slightly underestimating the valence bandgap and overestimating the O(2s) and O(2p) bandwidths. The calculations also underestimate the EMS intensity of the O(2p) band around the Γ-point. Simulation of the effects of multiple scattering in the calculated oxide bandstructures do not explain these systematic differences.
To report the birth of a normal healthy baby after a frozen ET (FET) with blastocysts that were frozen and thawed twice.
Case report.
Private infertility practice.
A 26-year-old female who presented ...with male factor infertility and polycystic ovarian disease.
One cycle of IVF-ET and FET no. 1 followed by the refreezing of blastocysts and FET no. 2.
Clinical pregnancy and live birth.
Thirty-six months after a successful IVF-ET cycle, FET no. 1 was performed with eight frozen blastocysts that were thawed. One blastocyst was transferred to the uterus and four were refrozen. The first FET resulted in a singleton pregnancy that ended in a spontaneous abortion after 7 weeks' gestation. Six months later, FET no. 2 was performed. All four refrozen blastocysts were thawed and transferred to the uterus. The second FET resulted in a singleton pregnancy and the birth of a normal healthy baby (male) weighing 3,005 g after 38 weeks' gestation.
Human blastocysts can be refrozen/thawed and produce a normal healthy baby after an FET. Further studies will be required to determine survival, implantation, and live birth rates with refrozen/thawed human blastocysts.
On low index nickel surfaces, repulsive interactions between atomic oxygen and CO drive the phase separation of these species into oxygen-rich and CO-rich islands. Because these adsorbates interact ...differently with crystallographic steps, the size and the structure of these islands are modified on stepped surfaces. In this experiment, the coadsorption-induced changes in the distribution of CO were monitored using IRRAS, and six different CO stretching bands were observed that were assigned to distinct local chemisorption environments. When oxygen fully saturated sites along the step edge, the steps were completely blocked from CO adsorption and virtually all the CO population on the terraces shifted from atop to bridge sites. This terrace site shift was similarly accomplished by atomic oxygen chemisorbed at terrace sites. From these coadsorption-induced changes in CO site distribution, constrained by the 10 A terrace width, it was concluded that the through-metal O-CO interaction responsible for this CO site shift must be operative over a range of 5 A. At theta sub 0 =0.18 ML, when oxygen occupied, but does not fully saturated the step edge, a new CO adsorption site was created, with a characteristic frequency of 1750 cm exp -1 . This new site was assigned to CO bonded to kinks along the step edge based upon its low intensity (approxgeometric kink density), enhanced binding strength and sensitivity to oxygen coverage. At higher oxygen coverages, compression of the CO adlayer was observed, with CO shifting to asymmetric bridge sites. As saturation coverage was approached, CO occupied weakly bound sites in close proximity (approx3 A) to O adatoms, with high characteristic frequencies of 2100 cm exp -1 .
Chromosomal translocation requires formation of paired double-strand DNA breaks (DSBs) on heterologous chromosomes. One of the most well characterized oncogenic translocations juxtaposes
c-myc and ...the immunoglobulin heavy-chain locus (
IgH) and is found in Burkitt's lymphomas in humans and plasmacytomas in mice. DNA breaks in
IgH leading to
c-myc/IgH translocations are created by activation-induced cytidine deaminase (AID) during antibody class switch recombination or somatic hypermutation. However, the source of DNA breaks at
c-myc is not known. Here, we provide evidence for the
c-myc promoter region being required in targeting AID-mediated DNA damage to produce DSBs in
c-myc that lead to
c-myc/IgH translocations in primary B lymphocytes. Thus, in addition to producing somatic mutations and DNA breaks in antibody genes, AID is also responsible for the DNA lesions in oncogenes that are required for their translocation.
The presence of diffuse intensity in the LEED pattern of clean Ni(119), a stepped Ni(100) surface, indicates a disorder in the distribution of (100) terrace lengths. This diffuse intensity is ...attenuated upon adsorption of small amounts of oxygen, indicating an adsorbate-induced ordering of the surface, apparent at oxygen concentrations as low as θO = 0.03 ML. The physical origin of the oxygen-induced ordering is explored by considering two alternatives: an increase in repulsive interactions between surface steps and an inhibition of kink formation along step edges. The degree of surface ordering is found consistent with an increase in surface stress of 200 dyne cm or an increase in kink formation energy of just 40 meV. At an oxygen coverage matching the number of available step sites (θO ≈ 0.20 ML), a distinctive (9 × 1) oxygen overlayer pattern emerges which, upon additional oxygen exposure, transforms into the p(2 × 2) pattern typical of oxygen adsorption on Ni(100) at θO ≈ 0.25 ML. LEED “fingerprinting” of the I-V characteristics of both the (9 × 1)-O Ni (119) and p (2 × 2)-Ni (119) patterns was used to deduce the local oxygen chemisorption geometry. We conclude that oxygen in the (9 × 1) overlayer occupies 4-fold hollow sites near the step edge. Based upon this adsorption site, an oxygen-induced increase in the kink formation energy is the likely physical origin of the step ordering.
•When Au is deposited on Ge(110) and heated, liquid AuGe eutectic alloy islands form.•The islands are elongated along11¯0. For T> 600 °C, the islands move along 11¯0.•A temperature gradient causes ...island motion towards hotter temperatures.•The island velocities fit a model of diffusion-driven motion of a liquid droplet.
The growth of low-dimensional nanostructures of Au on Ge(110) and their temperature-induced motion were observed with Low Energy Electron Microscopy (LEEM). Ge(110) was dosed with 0.5–4 ML of Au and heated to 850 °C. Above 500 °C, liquid AuGe eutectic alloy islands grew on the surface. Islands were 0.3–3.0µm in width, 1–10µm in length, and elongated in the 11¯0 direction. Above 600 °C, islands began moving with speeds of 0.1–1.0µm/s, absorbing smaller stationary islands upon collision and increasing in size to more than 100µm in width. A temperature gradient of ∼0.017 °C/µm across the sample results in a gradient in the Ge concentration across the islands, inducing their movement in the direction of increasing temperature. Optical microscopy confirmed that the large islands moved from the cooler edges of the sample towards its hotter center. The mechanism for motion of the droplets is discussed, and the island velocities fit well to a model for diffusion-driven motion of the liquid droplet. When the temperature was subsequently lowered, islands became supersaturated with Ge, which crystallized on the island edges.
Objective: To determine the prognostic accuracy of the fetal pulmonary artery acceleration time/ejection time (PATET) for the prediction of neonatal respiratory complications (NRCs) in pregnancies ...with preterm premature rupture of membranes (PPROM).
Methods: This is a prospective cohort of singleton pregnancies complicated by PPROM managed in our institution from October 2015 to April 2018. Inclusion criteria included mothers from 13 to 46 years of age and singleton pregnancies with PATET measurements <7 days prior to delivery. PATET was obtained by placing the Doppler caliper in the main pulmonary artery proximal to the bifurcation of this vessel. NRC was defined as: need for ventilatory support, respiratory distress syndrome (RDS), or lung hypoplasia. Logistic regression models and area under the receiver operating characteristic curves (ROC) were utilized to determine the prognostic accuracy of PATET and gestational age for NRC and RDS.
Results: Of 95 patients included, 46 had NRC (RDS = 33). PATET was a significant predictor of NRC (AUC 0.74; 95%CI: 0.61-0.83; p < .001) and RDS (AUC 0.69; 95%CI: 0.57-0.80; p = .021) in PPROM. Gestational age at delivery and gestational age at PPROM were also significantly associated with NRC and RDS. Their predictive accuracy for NRC was 0.87 and 0.84, and for RDS 0.85 and 0.86, respectively.
Conclusions: PATET is a statistically significant predictor for NRC in pregnancies with PPROM; however, its clinical use may be limited as gestational age is a better predictor of these outcomes.
Rationale: NRCs are common in pregnancies complicated by preterm prelabor rupture of membranes (PPROM). We aim to determine the prognostic accuracy of the fetal PATET for the prediction of neonatal NRC in these pregnancies. Our results indicate that PATET is a statistically significant predictor for NRC in pregnancies with PPROM; however, its clinical use may be limited, as gestational age is a better predictor of these outcomes.
Abstract Background Surgical length of stay (LOS) has been correlated with quality of care, with shorter stays implying better care. The relationship between LOS and postdischarge complications ...(PDCs) has not been evaluated effectively. Methods The 2005 to 2007 National Surgical Quality Improvement Program data were queried for patients undergoing elective colectomies. The outcome of interest was the development of a PDC. Multivariate analysis was then performed adjusting for demographics, surgical approach, and comorbidities. Results A total of 12,956 colectomies were analyzed with an overall PDC of 8.7%. LOS was not associated with increased odds of developing a PDC. The laparoscopic approach reduced the risk of PDCs by 30% (odds ratio = .70, 95% confidence interval, 0.61–0.81). Body mass index, female sex, the presence of diabetes mellitus, and prolonged operative time increased the odds of developing a PDC. Conclusions A shorter LOS did not correlate with a reduction in the likelihood of PDCs. Further investigation into the role of LOS as a measure of quality care is needed.
We search for new massive scalar particles X and Y through the resonant process X→YH→bb¯bb¯, where H is the standard model Higgs boson. Data from CERN LHC proton-proton collisions are used, collected ...at a centre-of-mass energy of 13 TeV in 2016–2018 and corresponding to an integrated luminosity of 138fb−1. The search is performed in mass ranges of 0.9–4 TeV for X and 60–600 GeV for Y, where both Y and H are reconstructed as Lorentz-boosted single large-area jets. The results are interpreted in the context of the next-to-minimal supersymmetric standard model and also in an extension of the standard model with two additional singlet scalar fields. The 95% confidence level upper limits for the production cross section vary between 0.1 and 150 fb depending on the X and Y masses, and represent a significant improvement over results from previous searches.
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