Wetting hysteresis induces effective unidirectional water transport through a fluctuating nanochannel

We propose a water pump that actively transports water molecules through nanochannels. Spatially asymmetric thermal fluctuations imposed on the channel radius cause unidirectional water flow without osmotic pressure, which can be attributed to hysteresis in the cyclic transition between the wetting/drying states. We show that the water transport depends on fluctuations, such as white, Brownian, and pink noises. Because of the high-frequency components in white noise, fast switching of open and close states inhibits channel wetting. Conversely, pink and Brownian noises generate high-pass filtered net flow. Brownian fluctuation leads to a faster water transport rate, whereas pink noise has a higher capability to overcome osmotic pressure in the opposite direction. A trade-off relationship exists between the resonant frequency of the fluctuation and the flow amplification. The proposed pump can be considered as an analogy for the reversed Carnot cycle, which is the upper limit on the energy conversion efficiency

BioGlue® coronary embolism during open heart surgery

AbstractIn cases of iatrogenic coronary embolism during cardiac surgery or percutaneous coronary intervention, small air bubbles or foreign bodies are directly injected, which usually result in serious adverse events if not treated promptly. We herein describe the case of a patient who developed acute myocardial infarction resulting in shock due to BioGlue® (CryoLife, Atlanta, GA, USA)-induced coronary embolism during the surgical repair of aortic dissection and was treated for retrieval of the material using a thrombectomy catheter.<Learning objective: Coronary embolism caused by surgical adhesives is a rare but potentially life-threatening complication. It is important for surgeons to promptly recognize and treat this serious condition in consultation with cardiologists.

Noninvasive Demonstration of Dual Coronary Artery Fistulas to Main Pulmonary Artery with 64-Slice Multidetector-Computed Tomography: A Case Report

Coronary artery fistulas, including coronary pulmonary fistulas, are usually discovered accidently among the adult population when undergoing invasive coronary angiographies. We report here a 58-year-old woman with dual fistulas originating from the left anterior descending coronary artery and right coronary sinus to the main pulmonary artery, demonstrating noninvasively with multidetector-computed tomography (MDCT) and transthoracic echocardiography (TTE)

Unsupervised deep learning for molecular dynamics simulations: a novel analysis of protein-ligand interactions in SARS-CoV-2 Mpro

Molecular dynamics (MD) simulations, which are central to drug discovery, offer detailed insights into protein-ligand interactions. However, analyzing large MD datasets remains a challenge. Current machine-learning solutions are predominantly supervised and have data labelling and standardisation issues. In this study, we adopted an unsupervised deep-learning framework, previously benchmarked for rigid proteins, to study the more flexible SARS-CoV-2 main protease (M-pro). We ran MD simulations of M-pro with various ligands and refined the data by focusing on binding-site residues and time frames in stable protein conformations. The optimal descriptor chosen was the distance between the residues and the center of the binding pocket. Using this approach, a local dynamic ensemble was generated and fed into our neural network to compute Wasserstein distances across system pairs, revealing ligand-induced conformational differences in M-pro. Dimensionality reduction yielded an embedding map that correlated ligand-induced dynamics and binding affinity. Notably, the high-affinity compounds showed pronounced effects on the protein's conformations. We also identified the key residues that contributed to these differences. Our findings emphasize the potential of combining unsupervised deep learning with MD simulations to extract valuable information and accelerate drug discovery

DC Arc Plasma Treatment for Defect Reduction in WC-Co Granulated Powder

Tungsten carbide&ndash;cobalt (WC&ndash;Co) agglomerated powder is widely used for additive manufacturing and spray coating, and a reduction in internal gaps in the powder is required to obtain a product of high quality. In this paper, we investigate plasma effects on agglomerated powder when WC&ndash;12%Co powder is directly subjected to direct current (DC) arc plasma treatment to reduce gaps in the WC&ndash;Co powder. We obtain a plasma-treated powder with reduced gaps among WC particles. Furthermore, plasma-treatment improves the sphericity of the powder particles, due to the spheroidization effect, so that the percentage of plasma-treated particles exceeding 95% sphericity is 50%, which is 1.7 times that of raw powder. Concern regarding the possible generation of W2C by plasma treatment is unfounded, with W2C levels kept very low according to X-ray diffraction (XRD) analysis, showing a value of 0.0075 for the area ratio W2C(002)/WC(100). XRD analysis also reveals that plasma treatment relaxes residual strains in the powder. From these results, the DC plasma treatment of WC agglomerated powder produces a spherical powder with fewer gaps and strains in the powder, making it more suitable for additive manufacturing while suppressing decarburization

Structural features of aquaporin 4 supporting the formation of arrays and junctions in biomembranes

A limited class of aquaporins has been described to form regular arrays and junctions in membranes. The biological significance of these structures, however, remains uncertain. Here we analyze the underlying physical principles with the help of a computational procedure that takes into account protein-protein as well as protein-membrane interactions. Experimentally observed array/junction structures are systematically (dis)assembled and major driving forces identified. Aquaporin 4 was found to be markedly different from the non-junction forming aquaporin 1. The environmental stabilization resulting from embedding into the biomembrane was identified as the main driving force. This highlights the role of protein-membrane interactions in aquaporin 4. Analysis of the type presented here can help to decipher the biological role of membrane arrays and junctions formed by aquaporin. © 2012 Elsevier B.V. All rights reserved