Aims: Vitamin D plays a role in controlling the function of vascular smooth muscle and endothelial cells, even in the pulmonary artery. We hypothesized that pulmonary artery elasticity were ...comprimised in individuals with relatively low vitamin D levels. Methods: Adult individuals with the complaint of shortness of breath were enrolled. They were divided into 2 groups according to vitamin D levels, with a cut-off of 20 ng/mL. Pulmonary artery stiffness (PAS) was calculated using the following formula: PAS (kHz/sec) = maximal frequency shift/pulmonary acceleration time. The six-minute walk distance (6MWD) was used to assess the functional exercise capability of subjects. Results: A total of 71 individuals (male: 31%) were enrolled. Subjects with low vitamin D levels had lower 6MWD than subjects with higher vitamin D levels (443.58 + or - 56.20 m vs. 483.20 + or - 58.43 m, p=0.007). The PAS was significantly higher in individuals with vitamin D level <20 ng/mL compared with subjects with vitamin D level > 20 ng/mL (11.65 + or - 3.76 vs. 9.46 + or - 2.53, respectively, p=0.011). Multiple regression showed that vitamin D level was inversely associated with PAS (beta=-0.280, p=0.009). Conclusions: We found that PAS was associated with lower vitamin D levels. Vitamin D deficiency might involved in the dynamics of the pulmonary artery vasculature, even in the absence of significant pulmonary artery pressure elevation. Keywords: Vitamin D level, pulmonary artery stiffness, echocardiography
Secondary infection of the aorta is a sporadic and life-threatening disease. It is usually caused by infection and abscess in an adjacent structure. The most common mechanism for secondary aortic ...infection is a psoas abscess eroding the aortic wall, which rarely results in non-aneurysmal aortic rupture. Primary treatment is surgical aortic reconstruction, but the risk of emergency surgical treatment is high. Endovascular aortic stent-graft implantation can be lifesaving in this setting by stopping the bleeding. However, the crucial question of durability and late infections remains unanswered and warrants long-term antibiotic treatment and follow-up. In this report, we present a case of primary psoas abscess, which resulted in non-aneurysmal aortic rupture and its endovascular treatment.
Secondary infection of the aorta is a sporadic and life-threatening disease. It is usually caused by infection and abscess in an adjacent structure. The most common mechanism for secondary aortic ...infection is a psoas abscess eroding the aortic wall, which rarely results in non-aneurysmal aortic rupture. Primary treatment is surgical aortic reconstruction, but the risk of emergency surgical treatment is high. Endovascular aortic stent-graft implantation can be lifesaving in this setting by stopping the bleeding. However, the crucial question of durability and late infections remains unanswered and warrants long-term antibiotic treatment and follow-up. In this report, we present a case of primary psoas abscess, which resulted in non-aneurysmal aortic rupture and its endovascular treatment.
This paper studies the achievable secure rate per source-destination pair in wireless networks. First, a path loss model is considered, where the legitimate and eavesdropper nodes are assumed to be ...placed according to Poisson point processes with intensities λ and λ e , respectively. It is shown that, as long as λ e /λ = o ((log n ) -2 ), almost all of the nodes achieve a perfectly secure rate of Ω(1/√ n ) for the extended and dense network models. Therefore, under these assumptions, securing the network does not entail a loss in the per-node throughput. The achievability argument is based on a novel multihop forwarding scheme where randomization is added in every hop to ensure maximal ambiguity at the eavesdropper(s). Second, an ergodic fading model with n source-destination pairs and n e eavesdroppers is considered. Employing the ergodic interference alignment scheme with an appropriate secrecy precoding, each user is shown to achieve a constant positive secret rate for sufficiently large n . Remarkably, the scheme does not require eavesdropper CSI (only the statistical knowledge is assumed) and the secure throughput per node increases as we add more legitimate users to the network in this setting. Finally, the effect of eavesdropper collusion on the performance of the proposed schemes is characterized.
This paper describes the 400 kV AC submarine link under the Dardanelles Strait composed of 12 submarine armoured single-core cross-linked polyethylene (XLPE)-insulated cables (plus a back-up power ...cable). The link consists of two parallel-operated double-circuit links named Lâpseki–Sütlüce I and Lâpseki–Sütlüce II. The transmissible power is 4000 MW (1000 MW per circuit) and the average length for a single-core cable is about 4.6 km: the submarine cables are part of overhead lines. This paper gives a wide account of the cable installations and, chiefly, of the cable protections on the seabed: different protection choices were extensively used (i.e., water jetting and mattressing).
Physical-Layer Security in TDD Massive MIMO Basciftci, Yuksel Ozan; Koksal, Can Emre; Ashikhmin, Alexei
IEEE transactions on information theory,
11/2018, Letnik:
64, Številka:
11
Journal Article
Recenzirano
Odprti dostop
We consider a single-cell downlink time-division duplex-based massive MIMO communication in the presence of an adversary capable of jamming and eavesdropping simultaneously. We show that the massive ...MIMO communication is naturally resilient to no training-phase jamming attack in which the adversary jams only the data communication and eavesdrops both the data communication and the training. Specifically, we show that the secure degrees of freedom (SDoF) attained in the presence of such an attack are identical to the maximum DoF attainable under no attack. Furthermore, we evaluate the number of base station (BS) antennas necessary in order to establish information theoretic security without even a need for Wyner encoding for a given rate of information leakage to the attacker. Next, we show that things are completely different once the adversary starts jamming the training phase. Specifically, we consider the pilot contamination attack, called training-phase jamming in which the adversary jams and eavesdrops both the training and the data communication. We show that under such an attack, the maximum achieved SDoF is identical to zero. Furthermore, the maximum achievable secure rates of users also vanish, even in the asymptotic regime in the number of the BS antennas. We finally address this attack and show that, under training-phase jamming , if the number of pilot signals is scaled in a certain way and the pilot signal assignments can be hidden from the adversary, the users achieve an SDoF identical to the maximum achievable DoF under no attack.
Novel poly(alkoxysilane)s with high oil and organic solvent absorbencies were prepared by a bulk polymerization technique via the condensation of 1,3-benzenedimethanol with different lengths of ...alkoxysilanes at 160 °C without using a catalyst. The influence of the length of the alkoxysilane on the polymer properties and swelling ratios was investigated. Swelling experiments in various solvents indicated that these cross-linked poly(alkoxysilane)s can be used as absorbents for oils and oil-derived organic solvents. The swelling features of the poly(alkoxysilane)s were determined by solvent absorption tests, swelling kinetics experiments, and desorption kinetics measurements. The absorption capacities of the poly(alkoxysilane)s were 50–725% for various organic solvents and oil derivatives such as gasoline and diesel. The structural and thermal properties of the cross-linked poly(alkoxysilane) polymers were determined by FTIR, solid-state 13C and 29Si cross-polarization magic angle spinning (CP-MAS) NMR, and thermal gravimetric analysis (TGA).
•Poly(alkoxysilane) oil absorbents with high absorption capacity were prepared.•The influence of the alkoxysilane length on polymer properties was investigated.•Poly(alkoxysilane) organogels can remove oil-organic solvents spills form water.•Increasing chain length of the alkoxysilane monomers increase the swelling capacity.•All synthesized polymers could be used several times without any capacity loss.
The purpose of this study is to investigate the effects of implemented social isolation measures on the characteristics of orthopedic pediatric traumas during this COVID-19 pandemic lockdown period.
...Patients who were admitted at our center between two time periods: April 3, 2019-May 31, 2019 (no lockdown period) and April 3, 2020-May 31, 2020 (lockdown period) were included to the study. Group 1 comprised 743 patients who were treated during no lockdown period, whereas Group 2 comprised 615 patients who were treated during lockdown period. Patients' medical records and radiographs were reviewed through our hospital's computer database. In addition, we recorded each patients' age and gender, their definite diagnosis, the anatomic location of the trauma, the type of trauma (fracture, dislocation, tendon injury, ligament injury, fracture dislocation, open fracture, etc.), the type of pediatric fracture (displaced fracture, torus fracture, epiphyseal fracture, pathological fracture, etc.), and the treatment method (non-operative/operative).
The mean age of the patients was significantly lower in Group 2 (p<0.001). There were significant differences between the groups in terms of anatomic locations of the traumas (p<0.001). The types of the traumas, pediatric traumas, and treatment were significantly different between the groups (p<0.001, p<0.001, and p<0.001, respectively). The frequency of operative treatment was significantly higher in Group 2 (p<0.001).
Our results demonstrated significant differences in patients' demographics as well as trauma characteristics during COVID-19 pandemic.
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