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

Research on Tangential Velocity Solution and Accuracy Analysis of Radar Target

In this paper, a calculation method for the tangential velocity solution of radar target based on linear vector method is proposed. It makes full use of the advantage of high precision radial velocity measurement of radar, and realizes the accurate computation of tangential velocity of radar target. Based on the actual measurement capability of continuous wave (CW) radar, the accuracy of the tangential velocity is analyzed. The feasibility of calculation method and accuracy analysis method is verified by simulation experiment and measured data of shooting range

Improved instance segmentation for slender urban road facility extraction using oblique aerial images

Slender urban road facilities (SURFs) with extreme aspect ratios are essential roles of the road network and exist everywhere in urban scenarios, such as street lamps, traffic lights, and monitors. Their information provides important knowledge for road safety, traffic control, urban planning, city management, etc. With low cost and high-efficiency benefits, oblique aerial images are easily captured to cover large-scale areas, which can be appropriately used to survey SURFs in urban areas automatically. Meanwhile, instance segmentation methods are frequently applied, predicting bounding boxes and semantic masks of objects simultaneously, yet a minority is delicately designed for SURFs. This research aims to propose an instance segmentation method to automatically extract SURFs from oblique aerial imagery, enhancing both the predicted bounding box and the segmented binary mask. First, we design a dense anchor ratio with an IoU-balanced sampling strategy (DASS) for proposal generation by statistical analysis to improve the predicted bounding box. The proposed sampling strategy can better cover the shape of slender proposals and alleviate the imbalance problem between the target objects and background. Regarding the typical instance segmentation architectures, the binary mask is segmented coarsely due to the downsampling operations. Second, we propose balanced fine-grained features (BFGF) merged into the instance segmentation process via a three-stage architecture, effectively improving the detector’s performance. Specifically, before feature incorporation, the multi-level feature pyramid is refined by rescaling and integrating to obtain balanced features. Moreover, to evaluate the proposed approaches, we contribute an Urban Road Facilities Dataset for our task, URFD, which contains 1075 images and 1378 instances labeled manually and enriches the open resource dataset. By comparative experiments, the proposed method performs superiority in SURF instance segmentation, obtaining an mAP of 0.888 of the predicted bounding box and an mAP of 0.876 of the segmented binary mask

Hot Topics and Challenges of Regenerative Nanoceria in Application of Antioxidant Therapy

As a new antioxidant, nanoceria is of significant importance in applications of medical and biological fields. In comparison with conventional organic antioxidants, nanoceria has multienzyme mimetic activity by Ce4+/Ce3+ redox cycle. This unique regenerative/autocatalytic property has been widely used in the aspects of free-radical scavenger, radiation protection, oxidative-stress-related disease, drug delivery, biosensor, tissue engineering, cancer biomarker, and anti-inflammatory. This paper reviews the latest breakthrough of nanoceria as an antioxidant in applications of medical and biological fields on the base of the authors’ research works on resistance to oxidation and cytotoxicity. The challenges of nanoceria encountered in applications in medical and biological fields are commented as well

Bu Shen Huo Xue decoction promotes functional recovery in spinal cord injury mice by improving the microenvironment to promote axonal regeneration

Abstract Background Bu-Shen-Huo-Xue (BSHX) decoction has been used in the postoperative rehabilitation of patients with spinal cord injury in China. In the present study, we aim to reveal the bioactive compounds in BSHX decoction and comprehensively explore the effects of BSHX decoction and the underlying mechanism in spinal cord injury recovery. Methods The main chemical constituents in BSHX decoction were determined by UPLC–MS/MS. SCI mice were induced by a pneumatic impact device at T9–T10 level of the vertebra, and treated with BSHX decoction. Basso–Beattie–Bresnahan (BBB) score, footprint analysis, hematoxylin–eosin (H&E) staining, Nissl staining and a series of immunofluorescence staining were performed to investigate the functional recovery, glial scar formation and axon regeneration after BSHX treatment. Immunofluorescent staining of bromodeoxyuridine (BrdU), neuronal nuclei (NeuN) and glial fibrillary acidic protein (GFAP) was performed to evaluate the effect of BSHX decoction on neural stem cells (NSCs) proliferation and differentiation. Results We found that the main compounds in BSHX decoction were Gallic acid, 3,4-Dihydroxybenzaldehyde, (+)-Catechin, Paeoniflorin, Rosmarinic acid, and Diosmetin. BSHX decoction improved the pathological findings in SCI mice through invigorating blood circulation and cleaning blood stasis in the lesion site. In addition, it reduced tissue damage and neuron loss by inhibiting astrocytes activation, and promoting the polarization of microglia towards M2 phenotype. The functional recovery test revealed that BSHX treatment improved the motor function recovery post SCI. Conclusions Our study provided evidence that BSHX treatment could improve the microenvironment of the injured spinal cord to promote axonal regeneration and functional recovery in SCI mice

Suppression of the Electrical Crosstalk of Planar-Type High-Density InGaAs Detectors with a Guard Hole

The resolution of InGaAs FPA detectors is degraded by the electrical crosstalk, which is especially severe in high–density FPAs. We propose a guard-hole structure to suppress the electrical crosstalk in a planar-type 640 × 512 15 μm InGaAs short wavelength infrared FPA detector. For comparison, the frequently used guard ring is also prepared according to the same processing. The calculation results show that the electrical crosstalk with a guard hole is suppressed from 13.4% to 4.5%, reducing by 66%, while the electrical crosstalk with a guard ring is suppressed to 0.4%. Furthermore, we discuss the effects of the guard ring and the guard hole on the dark current, quantum efficiency, and detectivity. Experimental results show the detector with a guard-hole structure has higher performance compared with the detector with a guard-ring structure, the dark current density is reduced by 60%, the QE is increased by 64.5%, and the detectivity is increased by 1.36 times, respectively. The guard-hole structure provides a novel suppression method for the electrical crosstalk of high-density InGaAs detectors

Raw-Cotton-Derived N‑Doped Carbon Fiber Aerogel as an Efficient Electrode for Electrochemical Capacitors

The carbon fiber aerogel with a high surface area, as a promising ideal electrode for electrochemical capacitors (ECs), has attracted tremendous attention because it can offer a fast charge–discharge rate and an exceptional rate capability. However, there is still a big challenge to acquire highly porous fiber aerogel with elastic properties and good flexibility. Herein, N-doped porous carbon fiber aerogel (N-CFA) has been successfully fabricated using raw cotton as a fibrous template to obtain shaped aerogels. ZIF-8, in situ fabricated on the surface of cotton, played the role of an active agent and nitrogen source to create a rich porous structure with a certain nitrogen content. Benefiting from the macromonolith morphology with good flexibility, favorable mechanical durability, nitrogen doping, anda high specific surface area, the N-CFA exhibits excellent electrochemical performance with a high capacity of 365 F g^–1 at a current of 0.5 A g^–1 and a remarkable rate capability of 65.8% from 0.5 to 100 A g^–1 as a binder-free electrode in ECs. Additionally, N-CFA also displays a high capacitance retention of 93.6% after 10000 consecutive cycles at 5 A g^–1. The strategy may offer a low-cost and scalable method to produce high-performance N-doped carbon aerogels for electrodes from biomass

Research on Vehicle Active Steering Stability Control Based on Variable Time Domain Input and State Information Prediction

The controller design of vehicle systems depends on accurate reference index input. Considering information fusion and feature extraction based on existing data settings in the time domain, if reasonable input is selected for prediction to obtain accurate information of future state, it is of great significance for control decision-making, system response, and driver’s active intervention. In this paper, the nonlinear dynamic model of the four-wheel steering vehicle system was built, and the Long Short-Term Memory (LSTM) network architecture was established. On this basis, according to the real-time data under different working conditions, the information correction calculation of variable time-domain length was carried out to obtain the real-time state input length. At the same time, the historical state data of coupled road information was adopted to train the LSTM network offline, and the acquired real-time data state satisfying the accuracy was used as the LSTM network input to carry out online prediction of future confidence information. In order to solve the problem of mixed sensitivity of the system, a robust controller for vehicle active steering was designed with the sideslip angle of the centroid of 0, and the predicted results were used as reference inputs for corresponding numerical calculation verification. Finally, according to the calculated results, the robust controller with information prediction can realize the system stability control under coupling conditions on the premise of knowing the vehicle state information in advance, which provides an effective reference for controller response and driver active manipulation

Raw-Cotton-Derived N‑Doped Carbon Fiber Aerogel as an Efficient Electrode for Electrochemical Capacitors

The carbon fiber aerogel with a high surface area, as a promising ideal electrode for electrochemical capacitors (ECs), has attracted tremendous attention because it can offer a fast charge–discharge rate and an exceptional rate capability. However, there is still a big challenge to acquire highly porous fiber aerogel with elastic properties and good flexibility. Herein, N-doped porous carbon fiber aerogel (N-CFA) has been successfully fabricated using raw cotton as a fibrous template to obtain shaped aerogels. ZIF-8, in situ fabricated on the surface of cotton, played the role of an active agent and nitrogen source to create a rich porous structure with a certain nitrogen content. Benefiting from the macromonolith morphology with good flexibility, favorable mechanical durability, nitrogen doping, anda high specific surface area, the N-CFA exhibits excellent electrochemical performance with a high capacity of 365 F g^–1 at a current of 0.5 A g^–1 and a remarkable rate capability of 65.8% from 0.5 to 100 A g^–1 as a binder-free electrode in ECs. Additionally, N-CFA also displays a high capacitance retention of 93.6% after 10000 consecutive cycles at 5 A g^–1. The strategy may offer a low-cost and scalable method to produce high-performance N-doped carbon aerogels for electrodes from biomass