Here we report how two-dimensional crystal (2DC) overlayers influence the recrystallization of relatively thick metal films and the subsequent synergetic benefits this provides for coupling surface ...plasmon-polaritons (SPPs) to photon emission in 2D semiconductors. We show that annealing 2DC/Au films on SiO
results in a reverse epitaxial process where initially nanocrystalline Au films gain texture, crystallographically orient with the 2D crystal overlayer, and form an oriented porous metallic network (OPEN) structure in which the 2DC can suspend above or coat the inside of the metal pores. Both laser excitation and exciton recombination in the 2DC semiconductor launch propagating SPPs in the OPEN film. Energy in-/out- coupling occurs at metal pore sites, alleviating the need for dielectric spacers between the metal and 2DC layer. At low temperatures, single-photon emitters (SPEs) are present across an OPEN-WSe
film, and we demonstrate remote SPP-mediated excitation of SPEs at a distance of 17 μm.
Cytochrome c oxidase (CcO) is an essential enzyme in mitochondrial and bacterial respiration. It catalyzes the four-electron reduction of molecular oxygen to water and harnesses the chemical energy ...to translocate four protons across biological membranes. The turnover of the CcO reaction involves an oxidative phase, in which the reduced enzyme (R) is oxidized to the metastable O
state, and a reductive phase, in which O
is reduced back to the R state. During each phase, two protons are translocated across the membrane. However, if O
is allowed to relax to the resting oxidized state (O), a redox equivalent to O
, its subsequent reduction to R is incapable of driving proton translocation. Here, with resonance Raman spectroscopy and serial femtosecond X-ray crystallography (SFX), we show that the heme a
iron and Cu
in the active site of the O state, like those in the O
state, are coordinated by a hydroxide ion and a water molecule, respectively. However, Y244, critical for the oxygen reduction chemistry, is in the neutral protonated form, which distinguishes O from O
, where Y244 is in the deprotonated tyrosinate form. These structural characteristics of O provide insights into the proton translocation mechanism of CcO.
Abstract
Background
Little is known about the health sequelae of pneumonia in persons with chronic kidney disease (CKD).
Methods
We studied adults with CKD in Stockholm during 2006–11, who not ...previously been diagnosed with lower respiratory tract infections. We used multivariable-adjusted Cox regression with pneumonia as a time-varying exposure to estimate hazard ratios (HRs) 95% confidence intervals (CIs) for the events of death, major adverse cardiovascular events (MACEs), acute kidney injury (AKI), CKD progression or hospitalization for urinary tract infections (UTIs)/sepsis. Cataract and knee/joint replacement served as negative control outcomes.
Results
We identified 71 931 adults (mean age 79 years, 59% women), of whom 8379 (12%) were diagnosed with pneumonia during follow-up; incident pneumonia was associated with 10 times higher adjusted mortality risk during the first 90 days HR = 10.0, 95% confidence interval (CI) 9.5–10.5 and double the mortality beyond 90 days from pneumonia diagnosis (HR = 2.0; 95% CI 1.9–2.1). Incident pneumonia was similarly associated with higher adjusted risk of MACE (<90 days: HR = 12.6; 95% CI 12.0–13.3; ≥90 days: HR = 1.5; 95% CI 1.4–1.6). The adjusted risk of CKD progression and UTI/sepsis hospitalization was highest within 90 days from pneumonia but remained elevated thereafter. For AKI, the association with incident pneumonia was only seen within 90 days. Neither cataract nor knee/joint replacement was related to pneumonia.
Conclusions
Incident pneumonia was associated with increased risks of MACE, CKD progression, severe UTI/sepsis and death, with risks highest soon after pneumonia diagnosis but extending beyond 90 days. Our findings highlight the susceptibility for adverse outcomes of CKD patients following pneumonia diagnosis, and may inform clinical decisions regarding vaccination strategies.
The magnetic states of Mn and Co atoms in Mn-rich and Ge-deficient Co2Mn1.20Ge0.38 (CMG) Heusler alloy thin films facing an MgO barrier were studied by means of x-ray absorption spectroscopy (XAS) ...and soft x-ray magnetic circular dichroism (XMCD). In particular, the CMG film-thickness dependence of the Mn and Co magnetic moments was investigated. A Co2+-like multiplet structure was not observed in all the Co L2,3-edge XAS and XMCD, indicating that, even in the ultrathin samples, the Co atoms were not oxidized, and were more strongly spin polarized than those in the thicker samples. With decreasing CMG film thickness from 4 ML to 2 ML, the spin magnetic moment of Mn increased and the Mn L2,3-edge XAS did not show a Mn2+-like multiplet structure films in contrast to the Co-rich CMG thin films as studied by Asakura et al. PRB, 82, 184,419 (2010), where the Mn atoms are strongly oxidized. The results show that Mn-rich CMG films are beneficial for device fabrications in spintronics when the film thickness has to be reduced to a few monolayers.
Background. Usually, immunoglobulin M (IgM) serologic analysis is not sufficiently specific to confirm Zika virus (ZIKV) infection. However, since IgM does not cross the placenta, it may be a good ...marker of infection in neonates. Methods. We tested blood from 42 mothers and neonates with microcephaly and collected cerebrospinal fluid (CSF) specimens from 30 neonates. Molecular assays were performed for detection of ZIKV, dengue virus, and chikungunya virus; IgM enzyme-linked immunosorbent assays and plaque-reduction neutralization tests (PRNTs) were performed to detect ZIKV and dengue virus. No control neonates without microcephaly were evaluated. Results. Among neonates, all 42 tested positive for ZIKV IgM: 38 of 42 serum specimens (90.5%) were positive, whereas 30 of 30 CSF specimens (100%) were positive. ZIKV IgM–specific ELISA ratios, calculated as the mean optical density (OD) of the test sample when reacted on viral antigen divided by the mean OD of the negative control when reacted with viral antigen, were higher in CSF specimens (median, 14.9 range, 9.3–16.4) than in serum (median, 8.9 range, 2.1–20.6; P = .0003). All ZIKV IgM–positive results among the neonates were confirmed by the detection of neutralizing antibodies. Mother/neonate pairs with primary ZIKV infection had neutralizing antibodies to ZIKV only, and mother/neonate pairs with ZIKV virus infection secondary to infection with another flavivirus had high titers of neutralizing antibodies to ZIKV. Among secondary infections, median titers in serum were 2072 (range, 232–12 980) for mothers and 2730 (range, 398–12 980) for neonates (P < .0001), and the median titer in CSF was 93 (range, 40–578) among neonates (P < .0001). Conclusions. Among neonates, detection of ZIKV IgM in serum is confirmatory of congenital ZIKV infection, and detection of ZIKV IgM in CSF is confirmatory of neurologic infection. Therefore, we recommend testing for ZIKV IgM in neonates suspected of having congenital ZIKV infection and performance of PRNTs in equivocal cases.
Atomic Structure of Graphene on SiO2 Ishigami, Masa; Chen, J. H.; Cullen, W. G. ...
Nano letters,
06/2007, Letnik:
7, Številka:
6
Journal Article
Recenzirano
Odprti dostop
We employ scanning probe microscopy to reveal atomic structures and nanoscale morphology of graphene-based electronic devices (i.e., a graphene sheet supported by an insulating silicon dioxide ...substrate) for the first time. Atomic resolution scanning tunneling microscopy images reveal the presence of a strong spatially dependent perturbation, which breaks the hexagonal lattice symmetry of the graphitic lattice. Structural corrugations of the graphene sheet partially conform to the underlying silicon oxide substrate. These effects are obscured or modified on graphene devices processed with normal lithographic methods, as they are covered with a layer of photoresist residue. We enable our experiments by a novel cleaning process to produce atomically clean graphene sheets.
Leucine (Leu), an essential amino acid, is known to stimulate protein synthesis in the skeletal muscle via mTOR complex 1 (mTORC1) activation. However, the intrinsic contribution of other amino acids ...to Leu-mediated activation of mTORC1 signaling remains unexplored. This study aimed to identify amino acids that can promote mTORC1 activity in combination with Leu and to assess the effectiveness of these combinations in vitro and in vivo. We found that tyrosine (Tyr) enhanced Leu-induced phosphorylation of S6 kinase (S6K), an indicator of mTORC1 activity, although it exerted no such effect individually. This booster effect was observed in C2C12 cells, isolated murine muscle, and the skeletal muscles of mice orally administered the amino acids. To explore the molecular mechanisms underlying this Tyr-mediated booster effect, the expression of the intracellular Leu sensors, Sestrin1 and 2, was suppressed, and the cells were treated with Leu and Tyr. This suppression enabled Tyr alone to induce S6K phosphorylation and enhanced the booster effect, suggesting that Tyr possibly contributes to mTORC1 activation when Sestrin-GAP activity toward Rags 2 (GATOR2) is dissociated through Sestrin knockdown or the binding of Sestrins to Leu. Collectively, these results indicate that Tyr is a key regulator of Leu-mediated protein synthesis.
Cytochrome c oxidase (CcO) reduces dioxygen to water and harnesses the chemical energy to drive proton translocation across the inner mitochondrial membrane by an unresolved mechanism. By using ...time-resolved serial femtosecond crystallography, we identified a key oxygen intermediate of bovine CcO. It is assigned to the PR-intermediate, which is characterized by specific redox states of the metal centers and a distinct protein conformation. The heme a₃ iron atom is in a ferryl (Fe4+ = O2−) configuration, and heme a and CuB are oxidized while CuA is reduced. A Helix-X segment is poised in an open conformational state; the heme a farnesyl sidechain is H-bonded to S382, and loop-I-II adopts a distinct structure. These data offer insights into the mechanism by which the oxygen chemistry is coupled to unidirectional proton translocation.
The study objective was to evaluate the outcomes of the extracardiac Fontan operation at a single institution.
We conducted a retrospective study of 398 patients from a single institution who ...underwent their initial extracardiac Fontan operation between 1997 and 2020. We determined the incidence of and risk factors for failure of the Fontan circulation, which includes death, Fontan takedown, heart transplantation, protein-losing enteropathy, plastic bronchitis, and functional status at the last follow-up.
The median follow-up time was 10.3 years (interquartile range, 6.4-14.6). The overall survival was 96% and 86% at 10 and 20 years after extracardiac Fontan operation, respectively. There were 6 early deaths (6/398, 1.5%) and 15 late deaths (15/398, 3.8%). Forty-nine patients (12.5%) developed failure of the Fontan circulation. Freedom from the failure of Fontan circulation was 88% at 10 years and 76% at 20 years. Risk factors for failure of the Fontan circulation were right ventricular dominance (hazard ratio, 4.7; P < .001; 95% CI, 2.1-10.5), aortic atresia (hazard ratio, 5.5; P < .001; 95% CI, 2.3-12.8), and elevated mean pulmonary artery pressure (hazard ratio, 2.3; P = .002; 95% CI, 1.2-6.7).
Rates of failure of the Fontan circulation are low after the contemporary extracardiac Fontan operation. Risk factors for failure of the extracardiac Fontan circulation include right ventricular dominance, aortic atresia, and elevated pulmonary artery pressures.
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