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Organic solvent reverse osmosis (OSRO) is an emerging and promising technology for the separation of organic mixtures, which is realized by differential transport rates of organics through polymer membranes. However, the solvent transport characteristics and separation mechanism within OSRO systems remain unclear. Herein, we investigate the solvent transport behavior in polymer membranes with intrinsic microporosity by combining nonequilibrium molecular dynamics simulations with solvent permeation examinations. The results indicate that organic molecules permeate through the micropores in a clustered state driven by both pressure and concentration gradients. The selectivity of solvents is co‐determined by their sorption and diffusion in the swollen polymer membranes with a microporous character. The sorption selectivity is predominant in the overall selectivity toward polar ethyl ether/n‐butanol separation, whereas diffusion selectivity is more critical in nonpolar 1,3,5‐triisopropylbenzene/toluene separation. Generally, this work provides valuable insights into the development of next‐generation OSRO membranes for solvent separation. [ABSTRACT FROM AUTHOR]

A high-resolution optical vector analyzer (OVA) with wide measurement bandwidth based on microwave photonic frequency downconversion is proposed and experimentally demonstrated. In the proposed OVA, two pairs of frequency-swept dual-tone signals with different frequency intervals are used as the probe light. After passing through a device under test (DUT), the probe light is transmitted into a low-speed photodetector to perform frequency downconversion. Then, an intermediate frequency (IF) photocurrent with a fixed frequency is generated, which carries the DUT response. Hence, a low-speed electrical phase-magnitude detector (EPMD) can be employed to extract the magnitude and group delay responses of the DUT. Compared with the OVAs using the high-speed PD and ultrawide EPMD, the proposed approach is low-cost and has a high signal-to-noise ratio. In an experiment, the probe light is generated by the 2nd-order nonlinearity of the electro-optic modulator. Therefore, compared with conventional OVAs based on optical single-sideband (OSSB) or optical double-sideband (ODSB) modulation, the proposed OVA can achieve wide measurement bandwidth, which is four times (or two times) of that of the OSSB-based OVA (or the ODSB-based OVA). A frequency resolution of 6 MHz and a measurement bandwidth of 120 GHz are achieved. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to systematically review the gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-MRI) findings of hepatocellular adenoma (HCA), especially focusing on the diagnostic value of low signal intensity (SI) in the hepatocyte-phase (HBP) for differentiating HCA from focal nodular hyperplasia (FNH). Methods: A thorough literature search was conducted in PubMed, Excerpta Medica Database (EMBASE) and China National Knowledge Infrastructure databases (CNKI) to identify studies evaluating Gd-EOB-DTPA-MRI presentations of HCA. Published studies using pathological examinations as the gold standard were included. The pooled proportions of low SI in the HBP, arterial-phase, portal venous-phase (PVP) in HCA were calculated, as well as pooled proportions of bleeding, fatty degeneration, and central scar. Meta-analysis was used to evaluate the diagnostic value of low SI in the HBP for HCA. Results: The search yielded 90 studies, with 8 assessing a total of 256 HCA cases included in this study, total of 229 lesions showed low signal in the HBP. Pooled proportions of low SI in the arterial-phase, PVP, and HBP were 2% (95% CI: 0.01-0.05), 39% (95% CI: 0.25-0.55), and 89% (95% CI: 0.80-0.94), respectively. Pooled proportions of bleeding, fatty degeneration, and central scar in HCA were 11% (95% CI: 0.03-0.19), 37% (95% CI: 0.27-0.49), and 10% (95% CI: 0.03-0.27), respectively. The meta-analysis revealed the following characteristics of low SI in the HBP for HCA diagnosis: 1) pooled sensitivity, 0.917 (95% CI: 0.86-0.96); 2) pooled specificity, 0.952 (95% CI: 0.91-0.98); 3) pooled positive likelihood ratio, 15.028 (95% CI: 7.10-31.82); 4) pooled negative likelihood ratio, 0.105 (95% CI: 0.07-0.17); 5) area under the ROC, 0.9802 (Q value of 0.9375), The sensitivity analysis showed that no single study was found to influence the overall pooled estimates significantly, which indicated the stability of the meta-analysis results were good. Conclusions: Low SI on the HBP of Gd-EOB-DTPA-MRI was helpful for the diagnosis of HCA and differentiating from FNH, but it was overvalued, especially for some HCA pathological subtypes. Combining low SI in the HBP with routine MRI presentations and the risk factors of liver diseases could substantially improve its diagnosis value for HCA as well as differential diagnosis.

Achilles tendinopathy is often attributed to overuse, but its pathophysiology remains poorly understood. Disruption to the molecular structure of collagen is fundamental for the onset and progression of tendinopathy but has mostly been investigated in vitro. Here, we interrogated the in vivo molecular structure changes of collagen in rat Achilles tendons following treadmill running. Unexpectedly, the tendons' collagen molecules were not mechanically unfolded by running but denatured through proteolysis during physiological post-run remodeling. We further revealed that running induces inflammatory gene expressions in Achilles tendons and that long-term running causes prolonged, elevated collagen degradation, leading to the accumulation of denatured collagen and tendinopathy development. For applications, we demonstrated magnetic resonance imaging of collagenase-induced Achilles tendon injury in vivo using a denatured collagen targeting contrast agent. Our findings may help close the knowledge gaps in the mechanobiology and pathogenesis of Achilles tendinopathy and initiate new strategies for its imaging-based diagnosis.

Background: Early and accurate diagnosis is vital for avoiding the development of nondisplaced fractures to displaced fractures. Dual-energy CT (Computed Tomography) can detect bone marrow edema (BME), which may help to detect non-displaced fractures., Aim: To evaluate the value of DECT (Dual-Energy Computed Tomography) VNCa (Virtual noncalcium) images for improving diagnostic performance and confidence in acute non-displaced knee fractures., Methods: 125 patients with clinical suspicion of knee fractures underwent both DECT and MR. Conventional linear-blended CT and VNCa images were obtained from DECT. First, five readers with varying levels of experience evaluated the presence of fractures on conventional linear-blended CT and graded their diagnostic confidence on a scale of 1 to 10. Then BME with VNCa images was evaluated and compared with MR. Finally, the VNCa images combined with conventional linear-blended CT images were used to reassess the presence of fractures and diagnostic confidence. Diagnostic performance and matched pair analyses were performed., Results: 20 non-displaced knee fractures were detected. The consistency test of VNCa images and MR by five radiologists showed Kappa values are 0.76, 0.79, 0.81,0.85,and 0.90,respectively. The diagnostic performance of all readers was improved when using VNCa images combined with conventional linear-blended CT compared with that with conventional linear-blended CT alone. Diagnostic confidence was improved with combined conventional linear-blended CT and VNCa images (median score:8,8,9,9, and 10, respectively) compared with conventional linear-blended CT alone (median score:7,7,8,9, and 9)., Conclusion: DECT VNCa images could improve the radiologists' diagnostic performance and confidence with varying levels of experience in the detection of non-displaced knee fractures., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)