Forty-four analogs of honokiol, a compound with known antibacterial activity, especially with respect to oral bacteria, were synthesized to explore the structure-activity relationships against the ESKAPE pathogens. Compounds with high therapeutic indices (hemolysis20/MIC) were identified. In particular, ester-linked compounds that would be less than environmentally durable than biaryl ether antibacterials such as the broadly used triclosan were found to be active. MRSA mutants could be generated against some, but not all, of the highly active compounds. Based on gene sequencing results, membrane permeability, intracellular sodium, and intracellular pH assays revealed overlapping mechanisms of action. 相似文献
Radiative cooling materials that can dynamically control solar transmittance and emit thermal radiation into cold outer space are critical for smart thermal management and sustainable energy-efficient buildings. This work reports the judicious design and scalable fabrication of biosynthetic bacterial cellulose (BC)-based radiative cooling (Bio-RC) materials with switchable solar transmittance, which are developed by entangling silica microspheres with continuously secreted cellulose nanofibers during in situ cultivation. Theresulting film shows a high solar reflection (95.3%) that can be facilely switched between an opaque state and a transparent state upon wetting. Interestingly, the Bio-RC film exhibits a high mid-infrared emissivity (93.4%) and an average sub-ambient temperature drop of ≈3.7 °C at noon. When integrating with a commercially available semi-transparent solar cell, the switchable solar transmittance of Bio-RC film enables an enhancement of solar power conversion efficiency (opaque state: 0.92%, transparent state: 0.57%, bare solar cell: 0.33%). As a proof-of-concept illustration, an energy-efficient model house with its roof built with Bio-RC-integrated semi-transparent solar cell is demonstrated. This research can shine new light on the design and emerging applications of advanced radiative cooling materials. 相似文献
An unusual expansion dynamics of individual spin crossover nanoparticles is studied by ultrafast transmission electron microscopy. After exposure to nanosecond laser pulses, the particles exhibit considerable length oscillations during and after their expansion. The vibration period of 50–100 ns is of the same order of magnitude as the time that the particles need for a transition from the low-spin to the high-spin state. The observations are explained in Monte Carlo calculations using a model where elastic and thermal coupling between the molecules within a crystalline spin crossover particle govern the phase transition between the two spin states. The experimentally observed length oscillations are in agreement with the calculations, and it is shown that the system undergoes repeated transitions between the two spin states until relaxation in the high-spin state occurs due to energy dissipation. Spin crossover particles are therefore a unique system where a resonant transition between two phases occurs in a phase transformation of first order. 相似文献
Recent technologies advancements promise to change our lives dramatically in the near future. A new different living society is progressively emerging, witnessed from the conception of novel digital ecosystems, where humans are expected to share their own spaces and habits with machines. Humanoid robots are more and more being developed and provided with enriched functionalities; however, they are still lacking in many ways. One important goal in this sense is to enrich their cognitive capabilities, to make them more “intelligent” in order to better support humans in both daily and special activities. The goal of this research is to set a step in bridging the gap between symbolic AI and connectionist approaches in the context of knowledge acquisition and conceptualization. Hence, we present a combined approach based on semantics and machine learning techniques for improving robots cognitive capabilities. This is part of a wider framework that covers several aspects of knowledge management, from representation and conceptualization, to acquisition, sharing and interaction with humans. Our focus in this work is in particular on the development and implementation of techniques for knowledge acquisition. Such techniques are discussed and validated through experiments, carried out on a real robotic platform, showing the effectiveness of our approach. The results obtained confirmed that the combination of the approaches gives superior performance with respect to when they are considered individually.
Virtual Reality - We examine peripheral interactions in XR environments, for which we propose a conceptual space with two specialized dimensions, interaction-attention and reality-virtuality. We... 相似文献
The aroma emanating from fruits can indicate the maturity level and thus the quality and shelf life of the products. In this work it is presented an odour sampling system system (called also electronic nose), to classify the aroma of Diospyros kaki, whose working parameters can have variable configuration making the system flexible. The system can be appropriately reconfigured for each type of sampling. It is formed by a metal oxide semiconductor (MOS) commercial sensors matrix, which are individually controlled, being able to modify by software several parameters of their operating point. Working this way there is not a limited number of sensors but a very high number of virtual sensors. The system shows the ability to discriminate aroma of two Diospyros kaki cultivars. Moreover the instrument is capable to distinguish the fruits, inside the persimmon cultivar cluster, according to the ripe state after few days of storage. 相似文献