Diffusion tensor imaging radiomics in lower-grade glioma: improving subtyping of isocitrate dehydrogenase mutation status

Neuroradiology - To evaluate whether diffusion tensor imaging (DTI) radiomics with machine learning improves the prediction of isocitrate dehydrogenase (IDH) mutation status of lower-grade gliomas...     

Differences in pancreatic volume,fat content,and fat density measured by multidetector-row computed tomography according to the duration of diabetes

Pancreatic volume and fat content might be associated with β-cell function or insulin resistance (IR). We investigated the difference in pancreatic volume and fat content between age- and body mass index (BMI)-matched normal subjects and patients with having different durations of type 2 diabetes (T2D). We compared pancreatic volume and fat parameters between 50 age- and BMI-matched normal subjects, 51 subjects with newly diagnosed type 2 diabetes (T2D-new), 53 subjects with T2D <5 years (T2D<5Y), and 52 subjects with T2D ≥5 years (T2D≥5Y). Age and BMI were matched to range of ±2 years and ±0.5 kg/m², respectively. Pancreatic volume and fat were measured by multidetector-row computed tomography with 64 detector-row scanner. The difference in Hounsfield units between pancreas and spleen (HUp–s) was investigated for fat density. Anthropometric and biochemical parameters including the homeostasis model assessment of IR (HOMA-IR) and the insulinogenic index (IGI) were measured. Compared with normal subjects, patients with T2D had significantly smaller pancreatic volume, greater pancreatic fat, and lower HUp–s. Among the groups with T2D, pancreatic volume decreased and pancreatic fat percentage and HUp–s increased from the T2D-new to the T2D<5Y and T2D>5Y groups. Pancreatic volume and fat and HUp–s values were associated with HbA1c and triglyceride levels. Pancreatic volume was correlated with IGI while pancreatic fat and HUp–s values were correlated with HOMA-IR. The current study suggests that pancreatic volume and fat deposition might be associated with the development and progression of T2D in Korean subjects.     

Quantitative Prediction of Oral Bioavailability of a Lipophilic Antineoplastic Drug Bexarotene Administered in Lipidic Formulation Using a Combined In Vitro Lipolysis/Microsomal Metabolism Approach

For performance assessment of the lipid-based drug delivery systems (LBDDSs), in vitro lipolysis is commonly applied because traditional dissolution tests do not reflect the complicated in vivo micellar formation and solubilization processes. Much of previous research on in vitro lipolysis has mostly focused on rank-ordering formulations for their predicted performances. In this study, we have incorporated in vitro lipolysis with microsomal stability to quantitatively predict the oral bioavailability of a lipophilic antineoplastic drug bexarotene (BEX) administered in LBDDS. Two types of LBDDS were applied: lipid solution and lipid suspension. The predicted oral bioavailability values of BEX from linking in vitro lipolysis with microsomal stability for lipid solution and lipid suspension were 34.2 ± 1.6% and 36.2 ± 2.6%, respectively, whereas the in vivo oral bioavailability of BEX was tested as 31.5 ± 13.4% and 31.4 ± 5.2%, respectively. The predicted oral bioavailability corresponded well with the oral bioavailability for both formulations, demonstrating that the combination of in vitro lipolysis and microsomal stability can quantitatively predict oral bioavailability of BEX. In vivo intestinal lymphatic uptake was also assessed for the formulations and resulted in <1% of the dose, which confirmed that liver microsomal stability was necessary for correct prediction of the bioavailability.     

Systematic determination of absolute absorption cross-section of individual carbon nanotubes

Optical absorption is the most fundamental optical property characterizing light–matter interactions in materials and can be most readily compared with theoretical predictions. However, determination of optical absorption cross-section of individual nanostructures is experimentally challenging due to the small extinction signal using conventional transmission measurements. Recently, dramatic increase of optical contrast from individual carbon nanotubes has been successfully achieved with a polarization-based homodyne microscope, where the scattered light wave from the nanostructure interferes with the optimized reference signal (the reflected/transmitted light). Here we demonstrate high-sensitivity absorption spectroscopy for individual single-walled carbon nanotubes by combining the polarization-based homodyne technique with broadband supercontinuum excitation in transmission configuration. To our knowledge, this is the first time that high-throughput and quantitative determination of nanotube absorption cross-section over broad spectral range at the single-tube level was performed for more than 50 individual chirality-defined single-walled nanotubes. Our data reveal chirality-dependent behaviors of exciton resonances in carbon nanotubes, where the exciton oscillator strength exhibits a universal scaling law with the nanotube diameter and the transition order. The exciton linewidth (characterizing the exciton lifetime) varies strongly in different nanotubes, and on average it increases linearly with the transition energy. In addition, we establish an empirical formula by extrapolating our data to predict the absorption cross-section spectrum for any given nanotube. The quantitative information of absorption cross-section in a broad spectral range and all nanotube species not only provides new insight into the unique photophysics in one-dimensional carbon nanotubes, but also enables absolute determination of optical quantum efficiencies in important photoluminescence and photovoltaic processes.Single-walled carbon nanotubes (SWNTs), a model one-dimensional nanomaterial system, constitute a rich family of structures (1). Each single-walled nanotube structure, uniquely defined by the chiral index (n,m), exhibits distinct electrical and optical properties (2–5). Quantitative information of SWNT absorption cross-section is highly desirable for understanding nanotube electronic structures, for evaluating quantum efficiency of nanotube photoluminescence (5, 6) and photocurrent (7–9), and for investigating the unique many-body effects in 1D systems (10–16). Despite its obvious importance, reliable experimental determination of nanotube absorption cross-section at the single-tube level is still challenging (17). Previous absorption measurements on ensemble nanotube samples only provide averaged behavior (18–20). Recent absorption studies of individual nanotubes, suffering from small absorption signals and/or slow laser-frequency scanning, cannot determine the absolute absorption cross-section and are limited in achievable spectral range (15, 21–23).We demonstrate here a high-sensitivity polarization-based homodyne method to measure nanotube absorption spectra. By manipulating the light polarization, we enhanced the nanotube-induced transmission contrast, ΔI/I, by two orders of magnitude, and this enhanced transmission contrast can be quantitatively related to nanotube absorption cross-section along and perpendicular to the nanotube axis. Using this polarization control together with supercontinuum laser source, we realized high-throughput and broadband absorption measurements at the single-tube level; combined with electron diffraction technique on the same tube, it enables absolute determination of absorption cross-sections of individual chirality-defined nanotubes, to our knowledge for the first time. We obtained quantitative absorption spectra of over 50 SWNTs of different chiralities, and established a phenomenological formula for absorption cross-sections of different nanotubes. The chirality-dependent nanotube absorption spectra reveal unique 1D photophysics in nanotubes, including a universal scaling behavior of exciton oscillator strength and of exciton resonance linewidth.     

Analysis of Cyazofamid and its Metabolite in the Environmental and Crop Samples Using LC–MS/MS

A rapid and robust LC–MS/MS method for the analysis of cyazofamid and its metabolite, 4-chloro-5-p-tolylimidazole-2-carbonitrile (CCIM), in environmental samples (soil and water) and a variety of crops (apple, mandarin, Kimchi cabbage, green pepper, potato and soybean) was established in this study. Those compounds were analyzed by selected reaction monitoring with electrospray ionization (positive mode) on LC–MS/MS. Method limit of quantitations were 2 ng g^?1 (cyazofamid) and 5 ng g^?1 (CCIM) for soil/crop samples, while 0.02 ng mL^?1 (cyazofamid) and 0.05 ng mL^?1 (CCIM) were achieved for water samples. Matrix effect (%) was different depending on sample matrices. For recovery tests, soil/crop samples were treated with QuEChERS method and water samples were extracted with dichloromethane. The recoveries of target analytes in the environmental and crop samples were 80.2 %–105.1 % for cyazofamid and 75.1 %–99.1 % for CCIM (coefficients of variation; ≤16.4 %).     

Tissue-Specific Antioxidant Responses in Pale Chub (Zacco platypus) Exposed to Copper and Benzo[a]pyrene

In this study, antioxidant responses including lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST), were evaluated in the liver, gill and muscle tissues of pale chub (Zacco platypus) exposed to copper (Cu) and benzo[a]pyrene (BaP). Cu exposure induced significant antioxidant responses in Z. platypus, particularly in the liver, whereas BaP exposure had a negligible effect. Following Cu exposure, both SOD and CAT activity increased in a concentration-dependent manner, showing significant correlations with malondialdehyde (MDA) levels as a measure of LPO (r = 0.646 and 0.663, respectively). SOD, CAT and GST mRNA levels were also enhanced following Cu exposure, except at 20 μg L^?1, although significant correlations with antioxidant enzyme activities were not found. The results of this study suggest that combined information on SOD and CAT activities together with LPO levels in the liver could be a useful indicator for assessing oxidative stress in freshwater fish.