Isotope engineering of carrier mobility via Fr\"ohlich electron-phonon interaction

Isotope effects on phonon properties and transport have been predicted and observed for decades. However, despite the crucial impact of electron-phonon interactions, the effect of isotopes on electron transport remains largely unexplored. Here, by using first-principles calculations, we theoretically predict that the electron mobility of lithium hydride (LiH) can increase by up to ~100% as $^3\rm{H}$ is replaced with $^1\rm{H}$. This remarkable phenomenon is primarily attributed to the isotope engineering of the Fr\"ohlich interaction by the mass-induced line shift of the longitudinal optical (LO) phonons. Notably, the isotope-dependent absorption of LO phonons dominates while the isotope-insensitive emission process is mostly suppressed due to energy conservation. We further propose general guidelines for evaluating isotope effects on carrier transport in different materials

Comparison of oxidative stress biomarkers in hypertensive patients with or without hyperhomocysteinemia

Hyperhomocysteinemia is an independent risk factor for cardiovascular impairment in hypertension. Oxidative stress is important in the molecular mechanisms associated with hypertension, but there are few studies focusing on the comparison of oxidative stress biomarkers in hypertensive patients with or without hyperhomocysteinemia. The study included 50 newly diagnosed hypertensive patients with hyperhomocysteinemia, 50 newly diagnosed hypertensive patients without hyperhomocysteinemia, and 50 age-matched healthy controls. Serum levels of malondialdehyde, nitric oxide, 8-isoprostane-F2ɑ, superoxide dismutase, catalase, and glutathione peroxides were compared. Levels of malondialdehyde and 8-isoprostane-F2ɑ were higher in both hypertensive groups than in the control group (8.3 ± 1.8 μmol/L vs. 6.5 ± 1.3 μmol/L vs. 4.3 ± 1.2 μmol/L, P < 0.05; 23.5 ± 12.1 pg/mL vs. 17.4 ± 10.3 pg/mL vs. 13.9 ± 7.5 pg/mL, P < 0.05), while levels of superoxide dismutase and catalase were lower in both hypertensive groups than in the control group (120.5 ± 13.7 U/mL vs. 131.3 ± 18.2 U/mL vs. 149.1 ± 14.6 U/mL, P < 0.05; 23.8 ± 7.4 U/mL vs. 24.6 ± 9.2 U/mL vs. 33.5 ± 8.2 U/mL, P < 0.05). In hypertensive subgroups, serum malondialdehyde levels were higher in the hyperhomocysteinemia group than the other group (8.3 ± 1.8 μmol/L vs. 6.5 ± 1.3 μmol/L; P < 0.05), and superoxide dismutase activities were lower in the hyperhomocysteinemia group than the other group (120.5 ± 13.7 U/mL vs. 131.3 ± 18.2 U/mL; P < 0.05). Moreover, in hypertensive patients, homocysteine levels were significantly correlated with malondialdehyde (r = 0.39, P < 0.01), 8-isoprostane-F2ɑ (r = 0.47, P < 0.05), superoxide dismutase (r = −0.51, P < 0.01), and catalase (r = −0.51, P < 0.05), respectively. Our findings demonstrated oxidative stress was more severe in hypertensive patients with hyperhomocysteinemia than those hypertensive patients without it. Besides, there were strong relationships between homocysteine activities and oxidative/antioxidative parameters, which indicated that homocysteine might aggravate the oxidative stress in hypertension to produce contributory effects on cardiovascular impairment

Maxent model application for tree pest monitoring

Tree pests can cause rapid and widespread damage, reducing the economic value of plants, production, in the case of fruit trees, and their role in mitigating climate change. There are several diseases that affect trees, including, for example, pine tree nematode (PWN), trunk fungal diseases, or Xylella fastidiosa (Xf).Mapping of diseased plants based on visual or automatic analysis of remote sensing data could be a useful support for in situ investigation planning. However, there is a clear need for better modeling methods to elaborate potential critical scenarios in order to early detect diseases (e.g. Xf) in host plants.Maxent (Maximum Entropy) has proved powerful when modeling species with available scarce presence-only occurrence data. The purpose is to predict potential distributions or explore expanding distributions. In this work we applied the Maxent model comparing local modeling results with worldwide cases towards a more comprehensive analysis of potential pest risk zones.Fil: Marzialetti, Pablo. Università degli Studi di Roma "La Sapienza"; ItaliaFil: Giovanni, Laneve. Università di Roma; ItaliaFil: Santilli, Giancarlo. Universidade do Brasília; BrasilFil: Huan, Wenjiang. Chinese Academy of Sciences; República de ChinaFil: Zappacosta, Diego Carlos. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaInternational Symposium on Geoscience and Remote SensingJapónInstitute of Electrical and Electronics EngineersThe Geoscience and Remote Sensing Societ

Simultaneous enhancement in electrical conductivity and Seebeck coefficient by single- to double-valley transition in a Dirac-like band

SnTe possesses a single- to double-valley transition in the conduction band minimum when a compressive strain is applied. Through a tight-binding analysis, it is shown that the variation of the band structure is attributed to the strain-induced delocalization of both the Sn-5s orbitals and Te-5p orbitals with different angular momenta. This effect can largely increase the electron density of states near the band edge and thus keep the Fermi level of the compressed SnTe closer to it, where the electrons have lower scattering rates. The strain-induced double valleys lead to simultaneous increases in the electrical conductivity and the Seebeck coefficient and thereby nearly four times the enhancement of the power factor at the doping concentration of 5×1019 cm–3. This work suggests a feasible concept that can be employed to promote the power factor of a Dirac semiconductor via manipulating the valley degeneracy in the conduction band minimum