Solid-state high harmonic spectroscopy for all-optical band structure probing of high-pressure quantum states.

High pressure has triggered various novel states/properties in condensed matter, as the most representative and dramatic example being near-room-temperature superconductivity in highly pressured hydrides (~200 GPa). However, the mechanism of superconductivity is not confirmed, due to the lacking of effective approach to probe the electronic band structure under such high pressures. Here, we theoretically propose that the band structure and electron-phonon coupling (EPC) of high-pressure quantum states can be probed by solid-state high harmonic generation (sHHG). This strategy is investigated in high-pressure Im-3m H3S by the state-of-the-art first-principles time-dependent density-functional theory simulations, where the sHHG is revealed to be strongly dependent on the electronic structures and EPC. The dispersion of multiple bands near the Fermi level is effectively retrieved along different momentum directions. Our study provides unique insights into the potential all-optical route for band structure and EPC probing of high-pressure quantum states, which is expected to be helpful for the experimental exploration of high-pressure superconductivity in the future.

Optical Control of Multistage Phase Transition via Phonon Coupling in MoTe_{2}.

The temporal characters of laser-driven phase transition from 2H to 1T^{'} has been investigated in the prototype MoTe_{2} monolayer. This process is found to be induced by fundamental electron-phonon interactions, with an unexpected phonon excitation and coupling pathway closely related to the nonequilibrium relaxation of photoexcited electrons. The order-to-order phase transformation is dissected into three substages, involving energy and momentum scattering processes from optical (A_{1}^{'} and E^{'}) to acoustic phonon modes [LA(M)] in subpicosecond timescale. An intermediate metallic state along the nonadiabatic transition pathway is also identified. These results have profound implications on nonequilibrium phase engineering strategies.

Giant acceleration of polaron transport by ultrafast laser-induced coherent phonons.

Polaron formation is ubiquitous in polarized materials, but severely hampers carrier transport for which effective controlling methods are urgently needed. Here, we show that laser-controlled coherent phonon excitation enables orders of magnitude enhancement of carrier mobility via accelerating polaron transport in a prototypical material, lithium peroxide (Li2O2). The selective excitation of specific phonon modes, whose vibrational pattern directly overlap with the polaronic lattice deformation, can remarkably reduce the energy barrier for polaron hopping. The strong nonadiabatic couplings between the electronic and ionic subsystem play a key role in triggering the migration of polaron, via promoting phonon-phonon scattering in q space within sub-picoseconds. These results extend our understanding of polaron transport dynamics to the nonequilibrium regime and allow for optoelectronic devices with ultrahigh on-off ratio and ultrafast responsibility, competitive with those of state-of-the-art devices fabricated based on free electron transport.

[Comparison study on diagnostic and prognostic value of N-terminal probrain natriuretic peptide and atrium natriuretic peptide in chronic congestive heart failure].

OBJECTIVE: To investigate the diagnostic and prognostic value of N-terminal probrain natriuretic peptide(NT-proBNP)and atrium natriuretic peptide(ANP)in chronic congestive heart failure. METHODS: One hundred and eighteen coronary heart disease patients were enrolled in the study. Among them 78 patients were accompanied by heart failure and 40 with no heart failure. Plasma NT-proBNP was determined with Elecsys Chemiluminescence Immunoassay method, and plasma ANP was determined with radioimmunoassay method.The results were compared with those of 40 healthy individuals. All patients were followed up accordingly. RESULTS: Compared with patients with no heart failure and healthy individuals, the patients with heart failure had a higher plasma NT-proBNP and ANP contents(P<0.05). Cardiac function grade IV patients had a significantly higher plasma NT-proBNP than cardiac function grade II and III patients, and their plasma ANP level was significanthy higher than that of cardiac function grade III patients, but there was no significantly difference in ANP content between cardiac function grade IV and II.The diagnostic sensitivity of NT-proBNP and ANP was 91.25% and 73.46%, respectively. The diagnostic specificity of NT-proBNP and ANP was 90.25%, 80.33%, respectively. In the heart failure group, it was found that there was no significant difference in the plasma NT-proBNP and ANP between the deaths and surviving patients. CONCLUSION: The diagnostic value of NT-proBNP in chronic heart failure is higher than that of ANP. According to our follow- up result, the plasma NT-proBNP and ANP can not be relied up on to predict short -term cardiogenic death in heart failure.

[Age- and gender-related changes of biochemical markers for bone metabolic turnover].

OBJECTIVE: To investigate the age- and gender-related changes in serum biochemical markers for bone metabolic turnover to establish the reference ranges for these markers for osteoporosis prevention and monitoring. METHODS: In 276 healthy individuals, serum type I collagen C-telopeptide (beta-Crosslaps), osteocalin and alkaline phosphatase levels were measured by electrochemiluminescence immunoassay, radioimmunoassay and consecutive monitoring, respectively. RESULTS: No significant changes in serum phosphatase was found in relation to age and gender. Serum beta-crosslaps levels tended to increase with age in male and female subjects, but only until the age of 50-59 years, such changes began to be statistically significant (P<0.05) as compared with the levels in the youngest group. Above this age range, beta-crosslaps level in female subjects increased dramatically, showing significant difference between adjacent age groups (P<0.05), which, however, was out observed in male subjects. Serum osteocalin level was lowered with age in female subjects before the age of 50 years, but a significant increase occurred at the age of 50-59 years (P<0.05) followed by a relatively stable and mild increase that did not result in significant difference between adjacent age groups. In male subjects, serum osteocalin level reached the peak level at the age of 30-39 years followed by stable and mild decrease with age. The ratio of beta-crosslaps/osteocalin tended to increase with age in both male and female subjects. CONCLUSION: There are age- and gender-related changes in serum beta-crosslaps, osteocalin and especially beta-crosslaps/osteocalin ratio, suggesting the value of testing serum beta-crosslaps and osteocalin in the prevention and treatment of osteoporosis.