Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Protective effects of taurine and betaine against neurotoxicity via inhibition of endoplasmic reticulum stress and inflammation signaling in the brain of mice fed a Western diet

Western diet (WD) has been shown to impair liver functions via endoplasmic reticulum (ER) stress and oxidative stress. Although osmolytes prevent liver dysfunction, little is known about the mechanisms by which they exert neuroprotective effects against WD-induced damage. We investigated neuroprotective effects of osmolytes and determined the involvement of inflammasome-mediated inflammation in liver and brain. Mice were fed a control diet, WD, or WD with taurine or betaine. Osmolyte supplementation attenuated serum lipid peroxidation and inflammatory cytokine levels in WD-fed mice. Oxidative stress, inflammasome-mediated inflammation, ER stress, and insulin resistance were lower in liver and brain of mice fed osmolyte-supplemented diet than in those fed WD. Moreover, they activated brain-derived neurotrophic factor signaling and decreased β-amyloid deposition and tau hyperphosphorylation in the brain. These data implicate that osmolytes might be promising neuroprotective dietary supplements for WD-induced brain damage, as well as for previously reported genetically and chemically induced brain damage

Fibril-Type Textile Electrodes Enabling Extremely High Areal Capacity through Pseudocapacitive Electroplating onto Chalcogenide Nanoparticle-Encapsulated Fibrils

Effective incorporation of conductive and energy storage materials into 3D porous textiles plays a pivotal role in developing and designing high-performance energy storage devices. Here, a fibril-type textile pseudocapacitor electrode with outstanding capacity, good rate capability, and excellent mechanical stability through controlled interfacial interaction-induced electroplating is reported. First, tetraoctylammonium bromide-stabilized copper sulfide nanoparticles (TOABr-CuS NPs) are uniformly assembled onto cotton textiles. This approach converts insulating textiles to conductive textiles preserving their intrinsically porous structure with an extremely large surface area. For the preparation of textile current collector with bulk metal-like electrical conductivity, Ni is additionally electroplated onto the CuS NP-assembled textiles (i.e., Ni-EPT). Furthermore, a pseudocapacitive NiCo-layered double hydroxide (LDH) layer is subsequently electroplated onto Ni-EPT for the cathode. The formed NiCo-LDH electroplated textiles (i.e., NiCo-EPT) exhibit a high areal capacitance of 12.2 F cm(-2) (at 10 mA cm(-2)), good rate performance, and excellent cycling stability. Particularly, the areal capacity of NiCo-EPT can be further increased through their subsequent stacking. The 3-stack NiCo-EPT delivers an unprecedentedly high areal capacitance of 28.8 F cm(-2) (at 30 mA cm(-2)), which outperforms those of textile-based pseudocapacitor electrodes reported to date. © 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.TRU

Micro/nano‐wrinkled elastomeric electrodes enabling high energy storage performance and various form factors

Abstract Stretchable elastomer‐based electrodes are considered promising energy storage electrodes for next‐generation wearable/flexible electronics requiring various shape designs. However, these elastomeric electrodes suffer from the limited electrical conductivity of current collectors, low charge storage capacities, poor interfacial interactions between elastomers and conductive/active materials, and lack of shape controllability. In this study, we report hierarchically micro/nano‐wrinkle‐structured elastomeric electrodes with notably high energy storage performance and good mechanical/electrochemical stabilities, simultaneously allowing various form factors. For this study, a swelling/deswelling‐involved metal nanoparticle (NP) assembly is first performed on thiol‐functionalized polydimethylsiloxane (PDMS) elastomers, generating a micro‐wrinkled structure and a conductive seed layer for subsequent electrodeposition. After the assembly of metal NPs, the conformal electrodeposition of Ni and NiCo layered double hydroxides layers with a homogeneous nanostructure on the micro‐wrinkled PDMS induces the formation of a micro/nano‐wrinkled surface morphology with a large active surface area and high electrical conductivity. Based on this unique approach, the formed elastomeric electrodes show higher areal capacity and superior rate capability than conventional elastomeric electrodes while maintaining their electrical/electrochemical properties under external mechanical deformation. This notable mechanical/electrochemical performance can be further enhanced by using spiral‐structured PDMS (stretchability of ~500%) and porous‐structured PDMS (areal capacity of ~280 μAh cm−2)