Search

Ventricular assist devices (VADs) are considered an effective treatment for patients with advanced heart failure, while complications associated with blood damage remain a burden. Structure design innovation has the potential to reduce hemolysis and improve hemocompatibility.In this research, a novel mixed-flow blood pump that integrates structural features of the axial and centrifugal VADs was proposed. The pump consists of an inducer, a mixed impeller supported by two ceramic pivot bearings, and a volute. The flow field and laminar viscous shear stress were analyzed by the in silico simulation. The hydraulic and hemolytic performance were evaluated in vitro by using a 3D printed pump.The flow field distribution showed that streamlines in the connection area were smoothly transitioned through structural integration and no irregular flow occurred in the entire flow channel. The axial blades work as a fluid accelerator (generating 18.56% of the energy), and the centrifugal blades provide the main pressure head. The proportion of fluid inside the pump exposed to low laminar viscous shear stress (50 Pa) and high laminar viscous shear stress (150 Pa) was 99.02% and 0.03%, respectively. The in vitro hemolysis test results showed that the NIH (Normalized Index of Hemolysis) value of the mixed pump is 0.0079 ± 0.0039 g/100 L (n = 6).It can be concluded that the mixed flow structure is effective at improving hydraulic performance, eliminating flow disturbance, and minimizing shear stresses. This novel pump design is expected to provide a new direction for the development of next-generation VADs.

Thrombosis induced by blood-contacting medical devices is still a major clinical problem, resulting in some serious complications such as infarction, irreversible tissue damage, and even death. Therefore, seeking an effective and safe surface modification approach to improve the hemocompatibility of the material is still urgent. In this research, a novel and facile approach was proposed to fabricate a robust honeycomb nanostructure on medical pure titanium surface by two-step anodic oxidation, which effectively enhanced the physicochemical performance and hemocompatibility of the material. Especially, the honeycomb nanostructure that underwent annealing treatment at 500 °C (HN-Ti-500 °C) presented significant performance to suppress the coagulation cascade in the

BackgroundIt is hypothesized that different levels of hormones especially serum testosterone level could explain the sex differences between men and women on the susceptibility and case fatality rate of COVID-19. However, traditional observational studies that support this hypothesis could not effectively establish the causal effects.ObjectiveUtilizing recently published genome-wide associations studies (GWAS) on serum Testosterone level and on COVID-19 related phenotypes, we sought to assess the causality through Mendelian Randomization (MR) analyses. We further applied a suite of statistical genomics methods to further explore the biological mechanisms.ResultsWe found that testosterone level is significantly associated with Covid-19 critical illness. All six MR methods yielded significant associations. There is no significant association between Testosterone and COVID-19 respiratory failure or COVID-19 susceptibility.ConclusionBased on the GWAS currently available, we provide support for a causal role of Testosterone on COVID-19 critical illness.Nevertheless, we recognize that the COVID-19 susceptibility GWAS effort is still ongoing and there is no such strong locus as CCR5 for HIV discovered for COVID-19.

Lignin-derived aromatic oligomers (LDAOs) are the primary components of lignin depolymerization products. They are typically utilized as renewable crosslinking agents or resin materials with a considerably lower application value than aromatic monomers. Notably, LDAOs are rich in quinone groups, which enable storage and release of charges. In this work, the feasibility of LDAOs as renewable charge storage materials was investigated. LDAOs were first reacted with formaldehyde to generate a synthetic polymer (SP-AOF) via a phenol-formaldehyde condensation reaction. SP-AOF was subsequently incorporated with reduced graphene oxide (rGO), namely rGO/SP-AOF. As expected, the hybrid electrode exhibited high specific capacitance (250 F/g), which was approximately three times higher than that of rGO (87 F/g). This was due to the presence of quinone groups in SP-AOF, which could contribute to the overall capacitance with pseudocapacitance. Moreover, the hybrid electrode was able to deliver a high specific capacitance of 210 F/g even at a high specific current of 10 A/g. 1H−13C heteronuclear single quantum coherence nuclear magnetic resonance (2D HSQC NMR) and phosphorus nuclear magnetic resonance spectroscopy (31P NMR) analyses revealed that SP-AOF displayed higher quinone content (3.76 mmol/g) than commercially available lignin (organosolv and alkali lignin), which resulted in higher energy storage performance. This study provides a promising strategy for the utilization of aromatic oligomers as raw materials to manufacture high-performance lignin-derived energy storage materials.

The construction of thermally conductive pathways to improve the thermal conductivity of the thermal interface materials (TIMs) is highly demanded due to the expanding trend of miniaturization, integration, and high-power of microelectronics, whereas the present TIMs could hardly provide the satisfying heat management performance. Herein, we report a progressive 3D self-assembly strategy for the fabrication of a composite film with excellent flexibility and thermally conductivity. Hexagonal boron nitride (BN)-OH is cross-linked with lignin nanoparticle (LNP) by borax and assembled onto cellulose nanofibrils (CNF), after further freeze-drying and pressing the composite film is thus formed. SEM analysis revealed that the BN-LNP thermally conductive pathways were successfully formed, and LNP acted as the cross-linking point of BN-OH. The 50 wt% filler loaded BN-LNP/CNF composite (BN-LNP50) exhibited a through-plane thermal conductivity of 2.577 W/mK, while this feature for the pure CNF film was only 0.413 W/mK, revealing an improvement of ~524%. It is worth noting that at the same filler content, the composite loaded with non-cross-linked BN/LNP mixture presented a much lower thermal conductivity (1.224 W/mK) compared to that was loaded with BN-LNP (2.084 W/mK). Particularly, the BN-LNP50 was thermally decomposed at 230 °C, demonstrating an increasement of 30% compared with the pure CNF film. Overall, this study provides an effective approach to fabricate BN-related thermally conductive materials with improved thermal management capacity.

In this short note, we present a sharp upper bound for the perturbation of eigenvalues of a singular diagonalizable matrix given by Stanley C. Eisenstat [3].

Web pages clustering is to divide different web pages into different classes according to traveling information of users so as to recommend relative pages to a user when the user is searching a website for his expectant information and to push relative pages to a user when the user is browsing one page. A similarity matrix, which shows similarity degree for any two pages in a website, is constructed according to users traveling paths to implement web pages clustering. A directional graph is created according to the users traveling paths at first and then a usage similarity matrix is constructed according to the directional graph. Structure disintegration model is adopted to analyze the similarity matrix and to transform the matrix into a catercorner matrix or a nether triangle matrix, which shows web pages clustering classes and relations among these classes., The original publication is available at JAIST Press http://www.jaist.ac.jp/library/jaist-press/index.html, IFSR 2005 : Proceedings of the First World Congress of the International Federation for Systems Research : The New Roles of Systems Sciences For a Knowledge-based Society : Nov. 14-17, 2138, Kobe, Japan, Symposium 6, Session 6 : Vision of Knowledge Civilization Society and Knowledge