Staphylococcus aureus is commonly associated with biofilm-related infections and contributes to the large financial loss that accompany nosocomial infections. The micrococcal nuclease Nuc1 enzyme limits biofilm formation via cleavage of eDNA, a structural component of the biofilm matrix. Solid surface hydrophobicity influences bacterial adhesion forces and may as well influence eDNA production. Therefore, it is hypothesized that the impact of Nuc1 activity is dependent on surface characteristics of solid surfaces. For this reason, this study investigated the influence of solid surface hydrophobicity on S. aureus Newman biofilms where Nuc1 is constitutively produced. To this end, biofilms of both a wild-type and a nuc1 knockout mutant strain, grown on glass, salinized glass and Pluronic F-127-coated silanized glass were analysed. Results indicated that biofilms can grow in the presence of Nuc1 activity. Also, Nuc1 and solid surface hydrophobicity significantly affected the biofilm 3D-architecture. In particular, biofilm densities of the wild-type strain on hydrophilic surfaces appeared higher than of the mutant nuc1 knockout strain. Since virulence is related to bacterial cell densities, this suggests that the virulence of S. aureus Newman biofilms is increased by its nuclease production in particular on a hydrophilic surface.
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http://dx.doi.org/10.1038/s41598-020-69084-x | DOI Listing |
J Am Chem Soc
January 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, College of Chemistry and Chemical Engineering, Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen University, Xiamen 361005, China.
Nitrogen fixation is essential for the sustainable development of both human society and the environment. Due to the chemical inertness of the N≡N bond, the traditional Haber-Bosch process operates under extreme conditions, making nitrogen fixation under ambient conditions highly desirable but challenging. In this study, we present an ultrasonic atomizing microdroplet method that achieves nitrogen fixation using water and air under ambient conditions in a rationally designed sealed device, without the need for any catalyst.
View Article and Find Full Text PDFAdv Healthc Mater
January 2025
Harvard Medical School, Harvard University, Boston, MA, 02115, USA.
Ultra-broadband photodetectors (UB-PDs) are essential in medical applications, public safety monitoring, and various other fields. However, developing UB-PDs covering multiple bands from ultraviolet to medium infrared remains a challenge due to material limitations. Here, a mixed-dimensional heterojunction composed of 2D WS/monodisperse hexagonal stacking (MHS) 3D PdTe particles on 3D Si is proposed, capable of detecting light from 365 to 9600 nm.
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January 2025
College of Chinese Medicinal Materials, Jilin Agricultural University, Changchun, 130118, China.
Natural plant-derived polysaccharides exhibit substantial potential for treating ulcerative colitis (UC) owing to their anti-inflammatory and antioxidant properties and favorable safety profiles. However, their practical application faces several challenges, including structural instability in gastric acid, imprecise targeting of inflamed regions, and limited intestinal retention times. To address these limitations, pH-responsive, colon-targeting microspheres (pWGPAC MSs) are developed for delivering phosphorylated wild ginseng polysaccharides (pWGP) to alleviate UC.
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January 2025
Key Laboratory of Testing Technology for Manufacturing Process MOE, Southwest University of Science and Technology, Mianyang 621010, China.
The directivity of the quasi-static component (QSC) is quantitatively investigated for evaluating the orientation of a micro-crack buried in a thin solid plate using the numerical simulation method. Based on the bilinear stress-strain constitutive model, a three-dimensional (3D) finite element model (FEM) is built for investigating the nonlinear interaction between primary Lamb waves and the micro-crack. When the primary Lamb waves at A0 mode impinge on the micro-crack, under the modulation of the contact acoustic nonlinearity (CAN), the micro-crack itself will induce QSC.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Faculty of Management, Lublin University of Technology, 20-618 Lublin, Poland.
This article presents the results of experimental studies on the influence of the geometry of high-voltage plasma actuator electrodes on the change in flow in the boundary layer and their influence on the change in the lift coefficient. The plasma actuator used in the described experimental studies has a completely different structure. The experimental model of the plasma actuator uses a large mesh ground electrode and different geometries of the high-voltage electrodes, namely copper solid electrodes and mesh electrodes (the use of mesh electrodes, large GND and HV is a new solution).
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