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The initial classic Fontan utilising a direct right atrial appendage to pulmonary artery anastomosis led to numerous complications. Adults with such complications may benefit from conversion to a total cavo-pulmonary connection, the current standard palliation for children with univentricular hearts.
A single institution, retrospective chart review was conducted for all Fontan conversion procedures performed from July, 1999 through January, 2017. Variables analysed included age, sex, reason for Fontan conversion, age at Fontan conversion, and early mortality or heart transplant within 1 year after Fontan conversion.
A total of 41 Fontan conversion patients were identified. Average age at Fontan conversion was 24.5 ± 9.2 years. Dominant left ventricular physiology was present in 37/41 (90.2%) patients. Right-sided heart failure occurred in 39/41 (95.1%) patients and right atrial dilation was present in 33/41 (80.5%) patients. The most common causes for Fontan conversion included atrial arrhythmia in 37/41 (90.2%), NYHA class II HF or greater in 31/41 (75.6%), ventricular dysfunction in 23/41 (56.1%), and cirrhosis or fibrosis in 7/41 (17.1%) patients. Median post-surgical follow-up was 6.2 ± 4.9 years. Survival rates at 30 days, 1 year, and greater than 1-year post-Fontan conversion were 95.1, 92.7, and 87.8%, respectively. Two patients underwent heart transplant: the first within 1 year of Fontan conversion for heart failure and the second at 5.3 years for liver failure.
Fontan conversion should be considered early when atrial arrhythmias become common rather than waiting for severe heart failure to ensue, and Fontan conversion can be accomplished with an acceptable risk profile.
Van der Waals (vdW) heterojunctions consisting of vertically-stacked individual or multiple layers of two-dimensional layered semiconductors, especially the transition metal dichalcogenides (TMDs), show novel optoelectronic functionalities due to the sensitivity of their electronic and optical properties to strong quantum confinement and interfacial interactions. Here, monolayers of n-type MoSe2 and p-type Mo1−xWxSe2 are grown by vapor transport methods, then transferred and stamped to form artificial vdW heterostructures with strong interlayer coupling as proven in photoluminescence and low-frequency Raman spectroscopy measurements. Remarkably, the heterojunctions exhibit an unprecedented photoconductivity effect that persists at room temperature for several days. This persistent photoconductivity is shown to be tunable by applying a gate bias that equilibrates the charge distribution. These measurements indicate that such ultrathin vdW heterojunctions can function as rewritable optoelectronic switches or memory elements under time-dependent photo-illumination, an effect which appears promising for new monolayer TMDs-based optoelectronic devices applications.
A number of thin silicon films are prepared through ultra-high-vacuum evaporation on optical quality fused quartz substrates with different growth temperatures. Through an analysis of grazing incidence X-ray diffraction results, a phase transition, from amorphous-to-crystalline, is found corresponding to increases in the growth temperature. The corresponding Raman spectra are also observed to change their form as the films go through this phase transition. Using a Raman peak decomposition process, this phase transition is then quantitatively characterized through the determination of the amount of intermediate-range order and the crystalline volume fraction for the various growth temperatures considered in this analysis. The possible device consequences of these results are then commented upon.
Prevalence of multidrug-resistant (MDR) gram-negative (GN) bacteria is increasing globally and is complicated by patient movement between acute and long-term care facilities (LTCFs). In Asia, the contribution of LTCFs as a source of MDR GN infections is poorly described. We aimed to define the association between residence in LTCFs and MDR GN bloodstream infections (BSIs).
Secondary analysis of data from an observational cohort.
Two tertiary referral hospitals in Singapore, including the 1,400-bed Tan Tock Seng Hospital and the 1,600-bed Singapore General Hospital.
Adult patients with healthcare-onset (HCO) or hospital-onset (HO) GN BSI.
Patients were identified from hospital databases using standard definitions. Risk factors for both MDR GN HCO and HO BSI were analyzed using a multivariable logistic regression model.
A total of 675 episodes of GN BSI occurred over a 31-month period. Residence in a LTCF was an independent risk factor for developing MDR GN BSI (odds ratio [OR], 5.1 [95% confidence interval (CI), 2.2–11.9]; P < .01) when antibiotics were not used within the preceding 30 days. This risk persisted beyond the first 48 hours of hospitalization (OR, 3.4 [95% CI, 1.3–9.0]; P = .01). Previous culture growing an MDR organism (OR, 1.8 [95% CI, 1.3–2.7]; P < .01), previous antibiotic use (OR, 1.8 [95% CI, 1.2–2.6]; P < .01), and intensive care unit stay (OR, 2.2 [95% CI, 1.2–3.9]; P = .01), increased the risk of MDR GN BSI.
Residence in a LTCF is an independent risk factor for MDR GN BSI. Attempts to contain MDR GN bacteria in large Asian cities, where the proportion of the population that is elderly is projected to increase, should include infection prevention strategies that engage LTCFs.
Topological insulators are a new class of materials with the ability to carry spin-polarized currents on their surfaces. Nuclear magnetic resonance (NMR) measurements can probe the magnetic interactions between specific isotopes and the electronic system of a material. We present 209Bi NMR spectra and relaxation rate data on single crystals of the topological insulator material Bi2Se3 grown under various conditions. Our NMR data on single crystals reveal a significant strength of coupling between the nuclear spins and the bulk carrier spins, suggesting that nuclear spins may have a sizeable effect on spin-polarized surface currents.
In recent years, lithic studies have emphasized the role of technology in the overall adaptation of past societies to their environments, including the economization of lithic resources. This paper explores how particular characteristics of individual, unretouched flakes can be altered in ways that increase their economy, as reflected in the ratio of edge length to mass. Results of controlled laboratory experiments are presented that identify exterior platform angle and platform depth as being primary independent variables affecting this ratio. These relationships are then tested against a number of archaeological assemblages.
Residual stress in MEMS is of inherent importance in various respects. This study proposes a specific method using ANSYS including the birth and death method and combined with the optimal method (SCGM) to reduce the residual stresses during the CMOS fabrication process. The suitable cooling temperature for decreasing the residual stress is proposed and available. It demonstrates that the suitable parameter on the fabrication can reduce the residual stress in MEMS devices without any extra manufacturing process or external apparatus. The proposed method can expand to simulate the realistic MEMS model effectively.
NGC 1097 is a nearby barred spiral galaxy believed to be interacting with the elliptical galaxy NGC 1097A located to its northwest. It hosts a Seyfert 1 nucleus surrounded by a circumnuclear starburst ring. Two straight dust lanes connected to the ring extend almost continuously out to the bar. The other ends of the dust lanes attach to two main spiral arms. To provide a physical understanding of its structural and kinematical properties, two-dimensional hydrodynamical simulations have been carried out. Numerical calculations reveal that many features of the gas morphology and kinematics can be reproduced provided that the gas flow is governed by a gravitational potential associated with a slowly rotating strong bar. By including the self-gravity of the gas disk in our calculation, we have found the starburst ring to be gravitationally unstable which is consistent with the observation in Hsieh et al. (2011). Our simulations also show that gas can flow into the region within the starburst ring even after its formation, leading to the coexistence of both a nuclear ring and a circumnuclear disk.
The influence of annealing time and annealing temperature under controlled partial pressure of selenium on the in-plane electrical transport properties of specimens of [(PbSe)0.99]1[WSe2]1 turbostratic nanolaminates was studied. The annealing treatments were found to be very effective in reducing carrier concentrations and improving carrier mobility in the annealed films, which is attributed to the reduction of compositional and structural defects. As a result, room temperature Hall mobilities greater than 60 cm2 V−1·s−1 are observed in spite of the small in-plane domain sizes (on the order of 10 nm) that are related to the turbostratic disorder. The technique appears promising for decreasing the concentration of kinetically trapped defects in these and related self-assembled nanostructures, a key challenge to evaluating the expected potential for controlling electrical and thermal transport properties via designed nanostructure in these and related materials.