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Among community cohorts, associations between clinical and metabolite factors and complex left atrial (LA) phasic function assessed by cardiac magnetic resonance (CMR) feature tracking (FT) are unknown. Longitudinal LA strain comprising reservoir strain (εs), conduit strain (εe) and booster strain (εa) and their corresponding peak strain rates (SRs, SRe, SRa) were measured using CMR FT. Targeted mass spectrometry measured 83 circulating metabolites in serum. Sparse Principal Component Analysis was used for data reduction. Among community adults (n = 128, 41% female) (mean age: 70.5 ± 11.6 years), age was significantly associated with εs (β = -0.30, p < 0.0001), εe (β = -0.3, p < 0.0001), SRs (β = -0.02, p < 0.0001), SRe (β = 0.04, p < 0.0001) and SRe/SRa (β = -0.01, p = 0.012). In contrast, heart rate was significantly associated with εa (β = 0.1, p = 0.001) and SRa (β = -0.02, p < 0.0001). Serine was significantly associated with εs (β = 10.1, p = 0.015), SRs (β = 0.5, p = 0.033) and SRa (β = -0.9, p = 0.016). Citrulline was associated with εs (β = -4.0, p = 0.016), εa (β = -3.4, p = 0.002) and SRa (β = 0.4, p = 0.019). Valine was associated with ratio of SRe:SRa (β = -0.4, p = 0.039). Medium and long chain dicarboxyl carnitines were associated with εs (β = -0.6, p = 0.038). Phases of LA function were differentially associated with clinical and metabolite factors. Metabolite signals may be used to advance mechanistic understanding of LA disease in future studies.

In this work, a high temperature THz detector based on a GaN high electron mobility transistor (HEMT) with nano antenna structures was fabricated and demonstrated to be able to work up to 200   °C. The THz responsivity and noise equivalent power (NEP) of the device were characterized at 0.14 THz radiation over a wide temperature range from room temperature to 200 °C. A high responsivity R v of 15.5 and 2.7 kV/W and a low NEP of 0.58 and 10 pW/Hz 0.5 were obtained at room temperature and 200 °C, respectively. The advantages of the GaN HEMT over other types of field effect transistors for high temperature terahertz detection are discussed. The physical mechanisms responsible for the temperature dependence of the responsivity and NEP of the GaN HEMT are also analyzed thoroughly.

In this study we report the existence of novel ultraviolet (UV) and blue emission in rare-earth based perovskite NdGaO 3 (NGO) and the systematic quench of the NGO photoluminescence (PL) by Ce doping. Study of room temperature PL was performed in both single-crystal and polycrystalline NGO (substrates and pellets) respectively. Several NGO pellets were prepared with varying Ce concentration and their room temperature PL was studied using 325 nm laser. It was found that the PL intensity shows a systematic quench with increasing Ce concentration. XPS measurements indicated that nearly 50% of Ce atoms are in the 4+ state. The PL quench was attributed to the novel concept of super hydrogenic dopant (SHD)", where each Ce 4+ ion contributes an electron which forms a super hydrogenic atom with an enhanced Bohr radius, due to the large dielectric constant of the host. Based on the critical Ce concentration for complete quenching this SHD radius was estimated to be within a range of 0.85 nm and 1.15 nm whereas the predicted theoretical value of SHD radius for NdGaO3 is ~1.01 nm.

We report highly efficient continuous-wave terahertz (THz) photoconductive antenna based photomixer employing nano-gap electrodes in the active region. The tip-to-tip nano-gap electrode structure provides strong THz field enhancement and acts as a nano-antenna to radiate the THz wave generated in the active region of the photomixer. In addition, it provides good impedance matching to the THz planar antenna and exhibits a lower RC time constant, allowing more efficient radiation especially at the higher part of the THz spectrum. As a result, the output intensity of the photomixer with the new nano-gap electrode structure in the active region is two orders of magnitude higher than that of a photomixer with typical interdigitated electrodes. Significant improvement in the THz emission bandwidth was also observed. An efficient continuous wave THz source will greatly benefit compact THz system development for high resolution THz spectroscopy and imaging applications.