| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Chai, Xin-Sheng, et al.
(författare)
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Spectrophotometric in-line monitoring of the electrochemical production of polysulfides using an ATR-probe
- 1998
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Ingår i: Process control and quality. - : Brill. - 0924-3089 .- 1568-5667. ; 11:2, s. 153-159
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Tidskriftsartikel (refereegranskat)abstract
- With an ATR-probe For the UV-vis range it is possible to apply spectrophotometry to very concentrated process liquors without dilution. In this paper the application of a new ATR-probe to the monitoring of sulfur species during an electrochemical process for production of polysulfides is presented. In this system, the temperature and the total salt concentration are relatively constant. A linear relation exists between the ATR-probe response and the concentration of adsorbing species. Therefore, the process can be followed by simple monitoring of a few wavelengths. The ATR-probe was easily implemented and showed no signs of deterioration in the hot strongly alkaline medium. Temperature has a significant effect on measurement with ATR-probes. Other factors that might also affect the measurements using an ATR-probe an briefly discussed.
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| 3. |
- Hsiung, Shih-Yi, et al.
(författare)
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Machine learning-based monosaccharide profiling for tissue-specific classification of Wolfiporia extensa samples
- 2023
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 322
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Tidskriftsartikel (refereegranskat)abstract
- Machine learning (ML) has been used for many clinical decision-making processes and diagnostic procedures in bioinformatics applications. We examined eight algorithms, including linear discriminant analysis (LDA), logistic regression (LR), k-nearest neighbor (KNN), random forest (RF), gradient boosting machine (GBM), support vector machine (SVM), Naïve Bayes classifier (NB), and artificial neural network (ANN) models, to evaluate their classification and prediction capabilities for four tissue types in Wolfiporia extensa using their monosaccharide composition profiles. All 8 ML-based models were assessed as exemplary models with AUC exceeding 0.8. Five models, namely LDA, KNN, RF, GBM, and ANN, performed excellently in the four-tissue-type classification (AUC > 0.9). Additionally, all eight models were evaluated as good predictive models with AUC value >0.8 in the three-tissue-type classification. Notably, all 8 ML-based methods outperformed the single linear discriminant analysis (LDA) plotting method. For large sample sizes, the ML-based methods perform better than traditional regression techniques and could potentially increase the accuracy in identifying tissue samples of W. extensa.
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| 4. |
- Liu, Guofeng, et al.
(författare)
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Helicity Inversion of Supramolecular Hydrogels Induced by Achiral Substituents
- 2017
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 11:12, s. 11880-11889
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Tidskriftsartikel (refereegranskat)abstract
- Probing the supramolecular chirality of assemblies and controlling their handedness are closely related to the origin of chirality at the supramolecular level and the development of smart materials with desired handedness. However, it remains unclear how achiral residues covalently bonded to chiral amino acids can function in the chirality inversion of supramolecular assemblies. Herein, we report macroscopic chirality and dynamic manipulation of chiroptical activity of hydrogels self-assembled from phenylalanine derivatives, together with the inversion of their handedness achieved solely by exchanging achiral substituents between oligo(ethylene glycol) and carboxylic acid groups. This helicity inversion is mainly induced by distinct stacking mode of the self-assembled building blocks, as collectively confirmed by scanning electron microscopy, circular dichroism, crystallography, and molecular dynamics calculations. Through this straightforward approach, we were able to invert the handedness of helical assemblies by merely exchanging achiral substituents at the terminal of chiral gelators. This work not only presents a feasible strategy to achieve the handedness inversion of helical nanostructures for better understanding of chiral self-assembly process in supramolecular chemistry but also facilities the development of smart materials with controllable handedness in materials science.
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| 5. |
- Shaoyang, Zhang, et al.
(författare)
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Image enhancement on fractional differential for road traffic and aerial images under bad weather and complicated situations
- 2014
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Ingår i: Transportation letters. - 1942-7867 .- 1942-7875. ; 6:4, s. 197-205
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Tidskriftsartikel (refereegranskat)abstract
- To enhance road traffic images and aerial images in bad weather, a new fractional differential operator is studied, and it is different from the traditional Tiansi operator. In the operator, for any sized kernel, the coefficient at the center position is not a constant, and it is the function of the fractional order and the kernel size; for the other pixels in the kernel, there is no zero coefficient value, and the values of the coefficients are calculated according to the distances from the center position on the basis of fractional differential. In experiments, a number of images are tested, and the results show that the studied operator is suitable for the vague images of the low contrast and rich textures, with less color changes. When compared with other newly proposed algorithms (e.g. Dark channel prior and Multiple scale Retinex, etc.) it performs better in some cases.
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| 6. |
- Wang, Guan, et al.
(författare)
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Transient analyses for China initiative Accelerator Driven System using the extended BELLA code
- 2023
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 190
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Tidskriftsartikel (refereegranskat)abstract
- China initiative Accelerator Driven System (CiADS) is a 10 MW lead-bismuth eutectic (LBE) cooled subcritical reactor loaded with UO2 fuels in the first phase, which is designed to demonstrate the engineering feasibility of the ADS concept. The transient analyses were performed to show the safety potential and dynamic characteristics of the CiADS subcritical reactor using the extended BELLA code. Typical scenarios, such as beam-trip transients, unprotected beam overpower (UBOP), unprotected and protected loss of flow (ULOF and PLOF), unprotected and protected loss of heat sink (ULOHS and PLOHS) and self-defined station blackout (SBO), were analyzed and simulated. The results indicate that, as a low-power reactor, the CiADS subcritical reactor has a large margin to avoid severe damage in the core. Short-term cladding failure caused by thermal fatigue under frequent beam trips may not happen since the variations of temperatures are relatively small. However, accelerated LBE corrosion combined with accumulated creep tends to be a risk under ULOF and ULOHS.
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| 7. |
- Wang, Xiangyang, et al.
(författare)
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Design and Experimental Verification of a Parallel Hip Exoskeleton System for Full-Gait-Cycle Rehabilitation
- 2022
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Ingår i: Journal of Mechanisms and Robotics. - : ASME International. - 1942-4302 .- 1942-4310. ; 14:5
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Tidskriftsartikel (refereegranskat)abstract
- Rehabilitation with exoskeletons after hip joint replacement is a tendency to achieve efficient recovery of people to rebuild their human motor functions. However, the kinematic mismatch between the kinematic and biological hip is a problem in most existing exoskeletons that can cause additional stress in the hip. To avoid secondary damage, the misalignment between the mechanical and biological hip joint of an exoskeleton must be compensated. This paper introduces a novel hip exoskeleton system based on parallel structure. The exoskeleton can inherently address the kinematic mismatch by introducing additional kinematic redundancy, while requiring no additional kinematic components and volumes. To achieve bidirectional full-gait-cycle walking assistance, a remote actuation system is designed for power delivery, and a control scheme is proposed to reject disturbances caused by gait dynamics during walking exercises. Human testing was carried out to evaluate the performance of the system. The results show that the exoskeleton has good human-machine kinematic compatibility and can achieve promising force tracking in the presence of gait dynamics.
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