Improved ferroelectric and piezoelectric properties of(Na_(0.5)K_(0.5))NbO_(3)ceramics via sintering in low oxygen partial pressure atmosphere and adding LiF

Dense(Na_(0.5)K_(0.5))NbO_(3)lead-free ceramics with the simple composition were prepared via sintering in low oxygen partial pressure(pO_(2),~10^(−12) atm)atmosphere and adding LiF.All the ceramics have pure orthorhombic structure.Compared to the LiF-added(Na_(0.5)K_(0.5))NbO_(3)ceramics sintered in air and the low pO_(2)-sintered pure(Na_(0.5)K_(0.5))NbO_(3)ceramics without LiF addition,the present ceramics exhibit improved piezoelectric and ferroelectric properties.The piezoelectric constant d33 is 125 pC/N,and the converse piezoelectric constant d_(33)^(*)is 186 pm/V.The dielectric constant and dielectric loss of the ceramics at room temperature and 1 kHz are 451 and 0.03,respectively.Under the measured electric field of 70 kV/cm,the remanent polarization is 25.9μC/cm^(2)and the coercive field is 13.9 kV/cm.Furthermore,if the base metals such as Cu and Ni powders were mixed into the green pellets and sintered in the low pO_(2)atmosphere,the base metals cannot be oxidized,suggesting possibility of using base metals as electrodes.

Deficiency of mitochondrial aldehyde dehydrogenase increases type 2 diabetes risk in males via autophagy dysregulation

Metrics To the editor:The diabetes epidemic has increasingly become a major public health concern worldwide.In 2014,there were 102.9 million diabetic adults in China,representing 24.4%of the world's diabetic population,even though China only comprised 18.7%of the global population at the time.[1]Furthermore,the estimated overall prevalence of diabetes and prediabetes was 10.9%and 35.7%,respectively,indicating China as one of the countries with the highest prevalence of diabetes in the world.[2]Although factors,including sedentary lifestyles and energy-dense diets,drive the diabetes epidemic,genetic architecture may also contribute to the susceptibility of an individual's response to environmental challenges.Aldehyde dehydrogenase(ALDH)2 is a key enzyme that eliminates toxic aldehydes by catalyzing their oxidation to non-reactive acids.Emerging evidence has suggested that individuals with ALDH2 deficiency have an increased risk of cardiovascular and metabolic diseases,in addition to alcohol intolerance,nitroglycerin tolerance,and carcinoma.[3]Notably,a unique ALDH2 loss-of-function allele,ALDH2∗2,is found in approximately 50%of the East Asian and 8%of the global populations.It has been reported that this ALDH2 mutation is associated with a higher prevalence of diabetes in coronary artery disease(CAD)patients,accompanied with increased C-reactive protein(CRP)levels.[4]ALDH2 mutation is also related to various diabetes risk factors,but the direct correlation remains elusive.Herein,we have explored the potential pathogenicity and mechanisms of ALDH2 deficiency in the development of type 2 diabetes in both laboratory and clinical settings.