On the rate of convergence of the Hamiltonian particle-mesh method

The Hamiltonian Particle-Mesh (HPM) method is a particle-in-cell method for compressible fluid flow with Hamiltonian structure. We present a numer- ical short-time study of the rate of convergence of HPM in terms of its three main governing parameters. We find that the rate of convergence is much better than the best available theoretical estimates. Our results indicate that HPM performs best when the number of particles is on the order of the number of grid cells, the HPM global smoothing kernel has fast decay in Fourier space, and the HPM local interpolation kernel is a cubic spline

Effects of crosstalk in WDM optical label switching networks due to wavelength switching of a tunable laser

rosstalk caused by switching events in fast tunable lasers in an optical label switching (OLS) system is investigated for the first time. A wavelength-division-multiplexed OLS system based on subcarrier multiplexed labels is presented which employs a 40-Gb/s duobinary payload and a 155-Mb/s label on a 40-GHz subcarrier. Degradation in system performance as the transmitters switch between different channels is then characterized in terms of the frequency drift of the tunable laser

Carbon Dynamics on the Molybdenum Carbide Surface during Catalytic Propane Dehydrogenation

The effect of the gas-phase chemical potential on surface chemistry and reactivity of molybdenum carbide has been investigated in catalytic reactions of propane in oxidizing and reducing reactant mixtures by adding H2, O2, H2O, and CO2 to a C3H8/N2 feed. The balance between surface oxidation state, phase stability, carbon deposition, and the complex reaction network involving dehydrogenation reactions, hydrogenolysis, metathesis, water-gas shift reaction, hydrogenation, and steam reforming is discussed. Raman spectroscopy and a surface-sensitive study by means of in situ X-ray photoelectron spectroscopy evidence that the dynamic formation of surface carbon species under a reducing atmosphere strongly shifts the product spectrum to the C3-alkene at the expense of hydrogenolysis products. A similar response of selectivity, which is accompanied by a boost of activity, is observed by tuning the oxidation state of Mo in the presence of mild oxidants, such as H2O and CO2, in the feed as well as by V doping. The results obtained allow us to draw a picture of the active catalyst surface and to propose a structure–activity correlation as a map for catalyst optimization

NOX-driven ROS formation in cell transformation of FLT3-ITD positive AML

In different types of myeloid leukemia, increased formation of reactive oxygen species (ROS) has been noted and associated with aspects of cell transformation including the promotion of leukemic cell proliferation and migration, as well as DNA-damage and accumulation of mutations. Work reviewed in this article has shown the involvement of NADPH oxidase (NOX)-derived ROS downstream of oncogenic protein-tyrosine kinases in both processes, and the related pathways have been partially identified. FLT3-ITD, an important oncoprotein in a subset of AML, causes activation of AKT and subsequently stabilization of p22phox, a regulatory subunit for NOX1-4. This process is linked to ROS formation and DNA damage. Moreover, FLT3-ITD signaling through STAT5 enhances expression of NOX4, ROS formation and inactivation of the protein-tyrosine phosphatase DEP-1/PTPRJ, a negative regulator of FLT3 signaling, by reversible oxidation of its catalytic cysteine residue. Genetic inactivation of NOX4 restored DEP-1 activity and attenuated cell transformation by FLT3-ITD in vitro and in vivo. Future work is required to further explore these mechanisms and their causal involvement in leukemic cell transformation, which may result in the identification of novel candidate targets for therapy

SCM optical label switching scheme in a WDM packet transmitter employing a switching SG-DBR laser

We demonstrate an SCM optical label switching scheme with spectral efficiency of 0.4bit/s/Hz and a spectral density figure of merit of 1. We then employ this scheme in a WDM transmitter subsystem and we investigate the detrimental effects that switching events in tunable lasers can have on such systems. The label performance is shown to hit an error floor when the tunable laser switches channels and this would cause incorrect routing of packets. The bit error rate is time resolved in order to better understand the problem and some possible solutions are discussed

Medical Comorbidities and Functional Dependent Living Are Independent Risk Factors for Short-Term Complications Following Osteotomy Procedures about the Knee

© The Author(s) 2018. Objective: To characterize rates and risk factors for adverse events following distal femoral osteotomy (DFO), high tibial osteotomy (HTO), and tibial tubercle osteotomy (TTO) procedures. Design: Patients undergoing DFO, HTO, or TTO procedures during 2005 to 2016 were identified in the American College of Surgeons National Surgical Quality Improvement Program. Rates of adverse events were characterized for each procedure. Demographic, comorbidity, and procedural factors were tested for association with occurrence of any adverse events. Results: A total of 1,083 patients were identified. Of these, 305 (28%) underwent DFO, 273 (25%) underwent HTO, and 505 (47%) underwent TTO. Mean ages for patients undergoing each procedure were the following: DFO, 51 ± 23 years; HTO, 40 ± 13 years; and TTO, 31 ± 11 years. The most common comorbidities for DFO were hypertension (34%) and smoking (17%); for HTO, hypertension (22%) and smoking (21%); and for TTO, smoking (20%) and hypertension (11%). Independent risk factors for occurrence of any adverse event were age ⩾45 years for DFO (odds ratio [OR] = 3.1, P \u3c 0.001) and HTO (OR = 2.3, P = 0.029), and body mass index \u3e30 for HTO (OR = 2.5, 95% confidence interval = 1.1-5.7, P = 0.031). When all osteotomy procedures were analyzed collectively, additional variables including diabetes mellitus (OR = 2.2, P = 0.017), chronic obstructive pulmonary disease (OR = 5.5, P = 0.003), and dependent functional status (OR = 3.0, P = 0.004) were associated with adverse events. Conclusions: The total rate of adverse events was not independently associated with the type of osteotomy procedure. In addition, patients with age \u3e45, diabetes mellitus, chronic obstructive pulmonary disease, and dependent functional status have greater odds for adverse events and should be counseled and monitored accordingly

Integrated demultiplexing and amplification of coherent optical combs

The explosive growth of the internet during the last few decades has been enabled by two complementary innovations in optical communications: the use of multiple optical channels within a single optical fibre, and the increase in the bandwidth of individual channels to hundreds of Gbps. Further increases in overall bandwidth look to be provided by more spectrally efficient optical superchannels that use coherent sub-carriers generated using optical orthogonal frequency division multiplexing (OFDM). Yet, a cost effective way of generating these signals has not been demonstrated. One crucial, but missing piece is an effective means to separate the closely frequency spaced optical sub-carriers from the coherent optical comb before placing information on each sub-carrier, and thus creating the OFDM signal. Here, we demonstrate a flexible strategy implemented in a compact photonic integrated circuit (PIC) that is used to separate and amplify these sub-carriers using on-chip injection locking