| 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. |
- Wang, Xiaoyang, 1965, et al.
(författare)
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The nonerythropoietic asialoerythropoietin protects against neonatal hypoxia-ischemia as potently as erythropoietin.
- 2004
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Ingår i: Journal of neurochemistry. - : Wiley. - 0022-3042 .- 1471-4159. ; 91:4, s. 900-10
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Tidskriftsartikel (refereegranskat)abstract
- Recently, erythropoietin (EPO) and the nonerythropoietic derivative asialoEPO have been linked to tissue protection in the nervous system. In this study, we tested their effects in a model of neonatal hypoxia-ischemia (HI) in 7-day-old rats (unilateral carotid ligation and exposure to 7.7% O(2) for 50 min). EPO (10 U/g body weight = 80 ng/g; n = 24), asialoEPO (80 ng/g; n = 23) or vehicle (phosphate-buffered saline with 0.1% human serum albumin; n = 24) was injected intraperitoneally 4 h before HI. Both drugs were protective, as judged by measuring the infarct volumes, neuropathological score and gross morphological score. The infarct volumes were significantly reduced by both EPO (52%) and asialoEPO (55%) treatment, even though the plasma levels of asialoEPO had dropped below the detection limit (1 pm) at the onset of HI, while those of EPO were in the nanomolar range. Thus, a brief trigger by asialoEPO before the insult appears to be sufficient for protection. Proteomics analysis after asialoEPO treatment alone (no HI) revealed at least one differentially up-regulated protein, synaptosome-associated protein of 25 kDa (SNAP-25). Activation (phosphorylation) of ERK was significantly reduced in asialoEPO-treated animals after HI. EPO and the nonerythropoietic asialoEPO both provided significant and equal neuroprotection when administered 4 h prior to HI in 7-day-old rats. The protection might be related to reduced ERK activation and up-regulation of SNAP-25.
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| 3. |
- Chen, Yihan, et al.
(författare)
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Characterization of the structure and analysis of the anti-oxidant effect of microalga Spirulina platensis polysaccharide on Caenorhabditis elegans mediated by modulating microRNAs and gut microbiota
- 2020
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier BV. - 0141-8130 .- 1879-0003. ; 163, s. 2295-2305
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Tidskriftsartikel (refereegranskat)abstract
- The antioxidant activity of Spirulina platensis polysaccharide (SPP) was investigated in Caenorhabditis elegans. Nuclearmagnetic resonance, Fourier-transform infrared, multi-angle laser light scattering, and GC-MS were used to identify the structural characteristics of SPP. It was composed of the -> 2)-alpha-L-Rhap-(1 ->, -> 4)-beta-D-Manp-(1 ->, -> 6)-beta-D-Glcp-(1 ->, -> 4)-beta-Xylp-(1 ->, -> 3)-beta-L-Araf-(1 ->, and -> 2)-beta-L-Fucp-(1 ->, respectively. The modulation of gut microbiota in C. elegans was determined using 16S rRNA gene high-throughput sequencing. The malondialdehyde (MDA) content was significantly decreased, while the total superoxide dismutase (T-SOD) and reactive oxygen species (ROS) levels were improved after SPP supplementation. The cellular mitochondrial content and apoptosis were significantly down-regulated. The obvious increased levels of the DAF-16 and SKN-1 mRNAs were observed in the SPP-treated group, while the levels of miR-48 and miR-51 were significantly reduced. Moreover, SPP administration significantly increased the abundance of Flavobacterium, Achromobacter, Empedobacter, Anaerolinea, and Pseudoalteromonas of the intestinal flora. Based on these results, S. platensis polysaccharides may be used as a functional food to ameliorate diseases related to oxidative stress.
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| 4. |
- Liu, Dan, et al.
(författare)
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Nutraceutical potentials of algal ulvan for healthy aging
- 2022
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier. - 0141-8130 .- 1879-0003. ; 194, s. 422-434
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Forskningsöversikt (refereegranskat)abstract
- Several theories for aging are constantly put forth to explain the underlying mechanisms. Oxidative stress, DNA dysfunction, inflammation, and mitochondrial dysfunction, along with the release of cytochrome c are some of these theories. Diseases such as type 2 diabetes mellitus, intestinal dysfunction, cardiovascular diseases, hepatic injury, and even cancer develop with age and eventually cause death. Ulva polysaccharides, owing to their special structures and various functions, have emerged as desirable materials for keeping healthy. These polysaccharide structures are found to be closely related to the extraction methods, seaweed strains, and culture conditions. Ulvan is a promising bioactive substance, a potential functional food, which can regulate immune cells to augment inflammation, control the activity of aging-related genes, promote tumor senescence, enhance mitochondrial function, maintain liver balance, and protect the gut microbiome from inflammatory attacks. Given the desirable physiochemical and gelling properties of ulvan, it would serve to improve the quality and shelf-life of food.
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| 5. |
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| 6. |
- Zanchetti, Alberto, et al.
(författare)
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Blood pressure and low-density lipoprotein-cholesterol lowering for prevention of strokes and cognitive decline: a review of available trial evidence.
- 2014
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Ingår i: Journal of Hypertension. - 1473-5598. ; 32:9, s. 1741-1750
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Forskningsöversikt (refereegranskat)abstract
- It is well established by a large number of randomized controlled trials that lowering blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) by drugs are powerful means to reduce stroke incidence, but the optimal BP and LDL-C levels to be achieved are largely uncertain. Concerning BP targets, two hypotheses are being confronted: first, the lower the BP, the better the treatment outcome, and second, the hypothesis that too low BP values are accompanied by a lower benefit and even higher risk. It is also unknown whether BP lowering and LDL-C lowering have additive beneficial effects for the primary and secondary prevention of stroke, and whether these treatments can prevent cognitive decline after stroke.
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| 7. |
- Zeng, Zhenjia, et al.
(författare)
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Utilizing Mixed Training and Multi-Head Attention to Address Data Shift in AI-Based Electromagnetic Solvers for Nano-Structured Metamaterials
- 2023
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Ingår i: Nanomaterials. - : MDPI AG. - 2079-4991. ; 13:20
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Tidskriftsartikel (refereegranskat)abstract
- When designing nano-structured metamaterials with an iterative optimization method, a fast deep learning solver is desirable to replace a time-consuming numerical solver, and the related issue of data shift is a subtle yet easily overlooked challenge. In this work, we explore the data shift challenge in an AI-based electromagnetic solver and present innovative solutions. Using a one-dimensional grating coupler as a case study, we demonstrate the presence of data shift through the probability density method and principal component analysis, and show the degradation of neural network performance through experiments dealing with data affected by data shift. We propose three effective strategies to mitigate the effects of data shift: mixed training, adding multi-head attention, and a comprehensive approach that combines both. The experimental results validate the efficacy of these approaches in addressing data shift. Specifically, the combination of mixed training and multi-head attention significantly reduces the mean absolute error, by approximately 36%, when applied to data affected by data shift. Our work provides crucial insights and guidance for AI-based electromagnetic solvers in the optimal design of nano-structured metamaterials.
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| 8. |
- Zhang, Lei, et al.
(författare)
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Nickel-induced charge redistribution in Ni-Fe/Fe3C@nitrogen-doped carbon nanocage as a robust Mott-Schottky bi-functional oxygen catalyst for rechargeable Zn-air battery
- 2022
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier. - 0021-9797 .- 1095-7103. ; 625, s. 521-531
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Tidskriftsartikel (refereegranskat)abstract
- Designing earth-abundant and advanced bi-functional oxygen electrodes for efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are extremely urgent but still ambiguous. Thus, metal-semiconductor nanohybrids were developed with functionally integrating ORR-active Ni species, OER-active Fe/Fe3C components, and multifunctional N-doped carbon (NDC) support. Expectantly, the resulted NDC nanocage embedded with Ni-Fe alloy and Fe3C particles, as assembled Mott-Schottky-typed catalyst, delivered a promoted half-wave potential of 0.904 V for ORR and a low overpotential of 315 mV at 10 mA/cm2 for OER both in alkaline media, outperforming those of commercial Pt/C and RuO2 counterparts. Most importantly, the optimized Ni-Fe/Fe3C@NDC sample also afforded a peak power density of 267.5 mW/cm2 with a specific capacity of 773.8 mAh/gZn and excellent durability over 80 h when used as the air electrode in rechargeable Zn-air batteries, superior to the state-of-the-art bi-functional catalysts. Ultraviolet photoelectron spectroscopy revealed that the introduction of Ni into the Fe/Fe3C@NDC component could well manipulate the electronic structure of the designed electrocatalyst, leading to an effective built-in electric field established by the Mott-Schottky heterojunction to expedite the continuous interfacial charge-transfer and thus significantly promote the utilization of electrocatalytic active sites. Therefore, this work provides an avenue for the designing and developing robust and durable Mott-Schottky-typed bi-functional catalysts for promising energy conversion.
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