Increased intestinal macromolecular permeability and urine nitrite excretion associated with liver cirrhosis with ascites

AIM： To determine intestinal permeability, the serum tumor necrosis factor （TNF）-α level and urine nitric oxide （NO） metabolites are altered in liver cirrhosis （LC） with or without ascites. METHODS： Fifty-three patients with LC and 26 healthy control subjects were enrolled in the study. The intestinal permeability value is expressed as the percentage of polyethylene glycol （PEG） 400 and 3350 retrieval in 8-h urine samples as determined by high performance liquid chromatography. Serum TNF-α concentrations and urine NO metabolites were determined using an enzyme-linked immunosorbent assay （ELISA） and Greiss reaction method, respectively. RESULTS： The intestinal permeability index wassignificantly higher in patients with LC with ascites than in healthy control subjects or patients with LC without ascites （0.88 ± 0.12 vs 0.52 ± 0.05 or 0.53 ± 0.03, P 〈 0.05） and correlated with urine nitrite excretion （r = 0.98）. Interestingly, the serum TNF-α concentration was significantly higher in LC without ascites than in control subjects or in LC with ascites （198.9 ± 55.8 pg/mL vs 40.9 ± 12.3 pg/mL or 32.1 ± 13.3 pg/mL, P 〈 0.05）. Urine nitrite excretion was significantly higher in LC with ascites than in the control subjects or in LC without ascites（ 1170.9± 28.7 μmol/L vs 903.1 ± 55.1 μmol/L or 956.7 ± 47.7 μmol/L, P 〈 0.05）. COMCLUSIOM： Increased intestinal macromolecular permeability and NO is probably of importance in the pathophysiology and progression of LC with ascites, but the serum TNF-α concentration was not related to LC with ascites.

Outage analysis of aerial semi-grant-free NOMA systems

In this paper,we analyze the outage performance of Unmanned Aerial Vehicles(UAVs)-enabled downlink Non-Orthogonal Multiple Access(NOMA)communication systems with the Semi-Grant-Free(SGF)transmission scheme.A UAV provides coverage services for a Grant-Based(GB)user and one Grant-Free(GF)user is allowed to utilize the same channel resource opportunistically.The analytical expressions for the exact and asymptotic Outage Probability(OP)of the GF user are derived.The results demonstrate that no-zero diversity order can be achieved only under stringent conditions on users'quality of service requirements.Subsequently,an efficient Dynamic Power Allocation(DPA)scheme is proposed to relax such data rate constraints.The analytical expressions for the exact and asymptotic OP of the GF user with the DPA scheme are derived.Finally,Monte Carlo simulation results are presented to validate the correctness of the derived analytical expressions and demonstrate the effects of the UAV's location and altitude on the OP of the GF user.

Free-space optical channel characterization in a coastal environment

Recently,FSO(Free-Space Optical Communication)has received a lot of attention thanks to its high data-rate transmission via unbounded unlicensed bandwidth.However,some weather conditions lead to significant degradation of the FSO link performance.Based on this context and in order to have a better understanding of the capabilities of FSO communication in a coastal environment,the effects of temperature and humidity on an FSO system are investigated in this study.An experiment is conducted using an open source FSO system that achieves a transmission rate of 1 Gbit/s at a distance of 70 m.Two new mathematical models are proposed to represent the effects of temperature and humidity on our developed FSO system operating at a wavelength of 1550 nm.The first model links the FSO attenuation coefficient to the air temperature in coastal regions,while the second model links the FSO attenuation coefficient to the humidity and the dew-point temperature.The key finding of this study is that FSO links can achieve maximum availability in a coastal city with normal variations in temperature and humidity.