Differential diagnosis of adrenal adenomas and metastases using spectral parameters in dual-layer detector spectral CT.

OBJECTIVE: To assess the diagnostic value of spectral parameters in differentiating adrenal adenomas from metastases based on dual-layer detector spectral CT (DLSCT). MATERIALS AND METHODS: Patients with adenomas or metastases who underwent enhanced DLSCT of the adrenals were enrolled. The CT values of virtual non-contrast images (CTVNC), iodine density (ID) values, and Z-effective (Z-eff) values, the normalized iodine density (NID) values, slopes of spectral HU curves (s-SHC), and iodine-to-CTVNC ratios of the tumors were measured in each phase. Receiver operating characteristic (ROC) curves were used to compare the diagnostic values. RESULTS: Ninety-nine patients with 106 adrenal lesions (63 adenomas, 43 metastases) were included. In the venous phase, all spectral parameters were significantly different between adenomas and metastases (all p < 0.05). The combined spectral parameters showed a better diagnostic performance in the venous phase than in other phase (p < 0.05). The iodine-to-CTVNC value had a larger area under the ROC curve (AUC) than the other spectral parameters in the differential diagnosis of adenomas and metastases, with a diagnostic sensitivity and specificity of 74.4% and 91.9%, respectively. In the differential diagnosis of lipid-rich adenomas, lipid-poor adenomas and metastases, the CTVNC value and s-SHC value also had a larger AUC than the other spectral parameters, with a diagnostic sensitivity of 97.7%, 79.1% and specificity of 91.2%, 93.1%, respectively. CONCLUSION: On DLSCT, the combined spectral parameters in the venous phase could help better distinguish adrenal adenomas from metastases. The iodine-to-CTVNC, CTVNC and s-SHC values had the highest AUC values in differentiating adenomas, lipid-rich adenomas and lipid-poor adenomas from metastases, respectively.

Raman intensity enhancement of molecules adsorbed onto HfS2 flakes up to 200 layers.

Newly emerging two-dimensional transition metal dichalcogenide HfS2 has received considerable attention recently due to its ultrahigh photoresponsivity, well-balanced carrier mobility and an appropriate band gap which offer potential in electronic and optoelectronic devices. In this work, HfS2 flakes up to 200 layers with varying color contrasts are fabricated and transferred on a SiO2/Si substrate. The Raman intensities of HfS2 flakes and Raman intensities of molecules adsorbed on HfS2 flakes are quantitatively studied both theoretically and experimentally by considering an optical interference effect. The effects of the main experimental factors: thickness of SiO2 and excitation wavelength on Raman intensities are also theoretically investigated. Due to the low absorption of HfS2, many strong high-order interference-induced enhancement peaks are observed which are different from high absorption materials like graphene and MoS2, in which only 2-4 interference-induced enhancement peaks exist. Due to the environmental instability of single layer HfS2 under ambient conditions, multi-layer HfS2 is a better choice than single layer HfS2 as a Raman scattering substrate which has a stronger Raman enhancement and a better environmental stability. The discovery here will expand the application of HfS2 flakes in molecular detection.

LC/MS-based metabolomics strategy to assess the amelioration effects of ginseng total saponins on memory deficiency induced by simulated microgravity.

Microgravity-induced memory deficiency seriously affects learning and memory ability of the astronaut during spaceflight, with few effective countermeasures. Panax ginseng C. A. Mey. has been used as a nootropic herb for thousands of years in Asian countries. Saponins are recognized as its major active components. Previous studies have shown that ginseng saponins offer protection against memory deficits caused by various factors. Nevertheless, the underlying mechanisms of their nootropic effects are still largely unknown. In this study, we evaluated the memory-improving effects of ginseng total saponins (GTS) on simulated microgravity hindlimb-unloaded rats using a metabolomics approach. After being exposed to a 7-days hindlimb unloading (HU), variations of plasmatic and hippocampal metabolic profiles of rats with and without GTS intervention were examined by a liquid chromatography-mass spectrometry (LC-MS) based untargeted metabolomics method. Subsequently, 8 hippocampal neurotransmitters were determined using a LC-MS/MS method. Finally, a LC-MS/MS based targeted metabolomics was performed to validate biomarkers found in the untargeted analysis. Besides, to support the metabolomics results, passive avoidance (PA) test, Nissl staining, and plasmatic corticosterone (CORT) levels determination were performed. The results showed that HU could lead to variations of 7 neurotransmitters and significantly different plasmatic and hippocampal metabolic profiles. GTS could restore most of the imbalanced neurotransmitters, especially glutamic acid and acetylcholine, and correct the levels of various disturbed learning and memory relevant biomarkers such as asparagine, phenylalanine, tyrosine, tryptophan, and choline. In addition, GTS could markedly ameliorate HU-induced memory deficiency, protect hippocampal neurons from damage, and down-regulate elevated CORT levels. In conclusion, GTS exhibits memory-improving effects mainly through regulating the metabolism of amino acids, neurotransmitters, choline, kynurenine, and sphingolipids. The findings of this study not only can deepen our understanding of the underlying molecular mechanisms of MG-induced memory disorders, but also provide scientific evidence for choosing ginseng as a countermeasure against MG-induced memory deficiency.