Association between food insecurity and risk of chronic diseases affecting the kidney in older Korean patients.

AIMS: This study aimed to examine the association between food insecurity and the prevalence of chronic diseases among older adults in South Korea and to compare the findings with data from the United States (US). MATERIALS AND METHODS: We analyzed data from the Korea National Health and Nutrition Examination Survey (KNHANES) V (2010 - 2012) and VI (2013 - 2015) and 4 years (2012 - 2015) of food security questionnaire data. The data of 46,189 National Health and Nutrition Examination Survey participants (1999 - 2016) were subjected to propensity score-matched (PSM) analysis. RESULTS: We included 7,914 individuals from the KNHANES. In the older group (age > 65 years), no differences were observed in the prevalence of hypertension, diabetes, chronic kidney disease (CKD), and metabolic syndrome across the income groups. Income, education, and food security had no impact on hypertension, diabetes, and CKD prevalence in the multivariate logistic analysis after PSM. CKD was not associated with food insecurity (odds ratio (OR), 1.26; 95% confidence interval (CI), 0.94 - 1.26) in the final model using the KNHANES data; however, the U.S. NHANES data showed that an increased risk of hypertension was associated with food insecurity (OR, 1.27; 95% CI, 1.04 - 1.55). CONCLUSION: As per the U.S. NHANES data, food insecurity was associated with a high prevalence of hypertension, while as per the South Korean KNHANES data, food insecurity was not found to be associated with CKD, indicating divergent relationships between food insecurity and chronic diseases in the two countries. Further research is needed to explore these differences.

Light Polarization-Controlled Conversion of Ultrafast Coherent-Incoherent Exciton Dynamics in Few-Layer ReS2.

Coherent light-matter interaction can transiently modulate the quantum states of matter under nonresonant laser excitation. This phenomenon, called the optical Stark effect, is one of the promising candidates for realizing ultrafast optical switches. However, the ultrafast modulations induced by the coherent light-matter interactions usually involve unwanted incoherent responses, significantly reducing the overall operation speed. Here, by using ultrafast pump-probe spectroscopy, we suppress the incoherent response and modulate the coherent-to-incoherent ratio in the two-dimensional semiconductor ReS2. We selectively convert the coherent and incoherent responses of an anisotropic exciton state by solely using photon polarizations, improving the control ratio by 3 orders of magnitude. The efficient modulation was enabled by transient superpositions of differential spectra from two nondegenerate exciton states due to the light polarization dependencies. This work provides a valuable contribution toward realizing ideal ultrafast optical switches.

Generation, transport and detection of valley-locked spin photocurrent in WSe2-graphene-Bi2Se3 heterostructures.

Quantum optoelectronic devices capable of isolating a target degree of freedom (DoF) from other DoFs have allowed for new applications in modern information technology. Many works on solid-state spintronics have focused on methods to disentangle the spin DoF from the charge DoF1, yet many related issues remain unresolved. Although the recent advent of atomically thin transition metal dichalcogenides (TMDs) has enabled the use of valley pseudospin as an alternative DoF2,3, it is nontrivial to separate the spin DoF from the valley DoF since the time-reversal valley DoF is intrinsically locked with the spin DoF4. Here, we demonstrate lateral TMD-graphene-topological insulator hetero-devices with the possibility of such a DoF-selective measurement. We generate the valley-locked spin DoF via a circular photogalvanic effect in an electric-double-layer WSe2 transistor. The valley-locked spin photocarriers then diffuse in a submicrometre-long graphene layer, and the spin DoF is measured separately in the topological insulator via non-local electrical detection using the characteristic spin-momentum locking. Operating at room temperature, our integrated devices exhibit a non-local spin polarization degree of higher than 0.5, providing the potential for coupled opto-spin-valleytronic applications that independently exploit the valley and spin DoFs.

Selectively tunable optical Stark effect of anisotropic excitons in atomically thin ReS2.

The optical Stark effect is a coherent light-matter interaction describing the modification of quantum states by non-resonant light illumination in atoms, solids and nanostructures. Researchers have strived to utilize this effect to control exciton states, aiming to realize ultra-high-speed optical switches and modulators. However, most studies have focused on the optical Stark effect of only the lowest exciton state due to lack of energy selectivity, resulting in low degree-of-freedom devices. Here, by applying a linearly polarized laser pulse to few-layer ReS2, where reduced symmetry leads to strong in-plane anisotropy of excitons, we control the optical Stark shift of two energetically separated exciton states. Especially, we selectively tune the Stark effect of an individual state with varying light polarization. This is possible because each state has a completely distinct dependence on light polarization due to different excitonic transition dipole moments. Our finding provides a methodology for energy-selective control of exciton states.