COVID-19 is a global catastrophic event that causes severe acute respiratory syndrome. The mechanism of the disease remains unclear, and hypoxia is one of the main complications. There is no currently approved protocol for treatment. The microbial threat as induced by COVID-19 causes the activation of macrophages to produce a huge amount of inflammatory molecules and nitric oxide (NO). Activation of macrophages population into a pro-inflammatory phenotype induces a self-reinforcing cycle. Oxidative stress and NO contribute to this cycle, establishing a cascade inflammatory state that can kill the patient. Interrupting this vicious cycle by a simple remedy may save critical patients’ lives. Nitrite, nitrate (the metabolites of NO), methemoglobin, and prooxidant-antioxidant-balance levels were measured in 25 ICU COVID-19 patients and 25 healthy individuals. As the last therapeutic option, five patients were administered methylene blue-vitamin C–N-acetyl Cysteine (MCN). Nitrite, nitrate, methemoglobin, and oxidative stress were significantly increased in patients in comparison to healthy individuals. Four of the five patients responded well to treatment. In conclusion, NO, methemoglobin and oxidative stress may play a central role in the pathogenesis of critical COVID-19 disease. MCN treatment seems to increase the survival rate of these patients. Considering the vicious cycle of macrophage activation leading to deadly NO, oxidative stress, and cytokine cascade syndrome; the therapeutic effect of MCN seems to be reasonable. Accordingly, a wider clinical trial has been designed. It should be noted that the protocol is using the low-cost drugs which the FDA approved for other diseases. Trial registration number NCT04370288.

Herein we report on a systematic investigation of the thermal expansion of select M n+1 AX n phases. The bulk dilatometric thermal expansion coefficient ␣ dil was measured in the 25-1200°C temperature range and the thermal expansion of more than 15 of these phases was studied by x-ray diffraction in the 25-800°C temperature range. The coefficient of thermal expansion for the a axis ␣ a ranged between ͑2.9Ϯ 0.1͒ ϫ 10 −6°C−1 ͑Nb 2 AsC͒ and ͑12.9Ϯ 0.1͒ ϫ 10 −6°C−1 ͑Cr 2 GeC͒ while the coefficient for the c axis ͑␣ c ͒ ranged between ͑6.4Ϯ 0.2͒ ϫ 10 −6°C−1 ͑Ta 2 AlC͒ and ͑17.6Ϯ 0.2͒ ϫ 10 −6°C−1 ͑Cr 2 GeC͒. Weak anisotropy in the thermal expansion was seen in most phases, with the largest value of ␣ c / ␣ a belonging to Nb 2 AsC. The Grüneisen parameters along the a and c directions were calculated from ab initio values for the elastic compliances and were relatively isotropic. A good correlation was found between the thermal expansion anisotropy and the elastic constant c 13 and we conclude that the anisotropy in thermal expansion is related to the bonding between the M − A elements.

In this paper we report on the electronic, magnetotransport, thermoelectric, and thermal properties of Ti3Al(C0.5,N0.5)2, Ti2Al(C0.5,N0.5), and Ti2AlN. The electrical conductivities, Hall coefficients, and magnetoresistances are analyzed within a two-band framework and compared with the end members, Ti2AlC and Ti3AlC2. The analysis shows that all compounds are compensated conductors with hole and electron carrier densities of about 1.5×1027 m−3. The room temperature thermal conductivities of the carbonitrides are both over ≈50 W/mK, with the phonon contribution of Ti3Al(C0.5,N0.5)2 particularly large at over 35 W/mK. The low-temperature specific heat of Ti3Al(C0.5,N0.5)2 and Ti2Al(C0.5,N0.5) yield Debye temperatures of 685 and 724 K, respectively, comparable to those of the end members.

No abstract

No abstract