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- 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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- Aad, G, et al.
(författare)
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- 2015
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swepub:Mat__t
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- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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- Cui, Xing-Mei, et al.
(författare)
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Unique UV-Erasable In-Ga-Zn-O TFT Memory With Self-Assembled Pt Nanocrystals
- 2013
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In: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 34:8, s. 1011-1013
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Journal article (peer-reviewed)abstract
- Semiconducting amorphous indium-gallium-zinc oxide (a-IGZO) films are integrated with an Al2O3/Pt-nanocrystals/ Al2O3 gate-stack to form UV-erasable thin-film transistor (TFT) memory. The threshold voltage (V-th), sub-threshold swing, I-ON/I-OFF ratio, and effective electron mobility of the fabricated devices are 2.1 V, 0.39 V/decade, similar to 10(6), and 8.4 cm(2)/V.s, respectively. A positive V-th shift of 2.25 V is achieved after 1-ms programming at 10 V-th, whereas a negative V-th shift as large as 3.48 V is attained after 5-s UV erasing. In addition, a 10-year memory window of 2.56 V is extrapolated at room temperature. This high-performance a-IGZO TFT memory is suitable for optical touch-panel applications.
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- Hsieh, Yu-Hsin, et al.
(author)
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Collaborative Home-Visit Program for Young Children With Motor Delays in Rural Taiwan : A Pilot Randomized Controlled Trial
- 2020
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In: Physical Therapy. - : Oxford University Press (OUP). - 0031-9023 .- 1538-6724. ; 100:6, s. 979-994
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Journal article (peer-reviewed)abstract
- Background. Caregiver engagement and collaborative team early childhood intervention (ECI) services are international trends; however, relevant evidence of collaborative home-visiting ECI in rural areas is as yet undetermined.Objective. The study aimed to investigate the effectiveness of a collaborative ECI program in a rural area of Taiwan.Design. The study was a pilot randomized control led trial.Methods. Children aged 6 to 33 months experiencing motor delays and their caregivers were enrolled in Taitung, Taiwan. Using stratified randomization, 24 participants were allocated to either experimental or control groups, and both received 5 home visits within 3 months. The experimental group received ECI services based on the International Classification of Functioning, Disability and Health framework and family-centered approaches. The control group received regular home visits by local social workers. Child outcomes included Pediatric Evaluation of Disability Inventory Chinese Version and Peabody Developmental Motor Scale, 2nd edition. Family outcomes included the Disability-Adapted Infant–Toddler version of Home Observation for Measurement, and Chinese versions of the Knowledge of Infant Development Inventory and Parental Stress Index-Short Form. A tester blinded to the study conducted assessments at baseline, postintervention, and 3-month follow-up. Two-way mixed analysis of variance was used with α = .05 (2-tailed).Results. The experimental group improved scores on the Disability-Adapted Infant–Toddler version of Home Observation for Measurement significantly more than the control group with an effect size of 0.64 at follow-up. In other outcomes, both groups showed no significant differences. The follow-up rate was 69%, and adherence to the ECI program was acceptable.Limitations. A limitation of the study was the heterogeneity of the sample.Conclusions. This pilot study revealed possible effectiveness in implementing collaborative ECI programs based on family-centered approaches and the International Classification of Functioning, Disability and Health in rural areas. Larger field studies are needed to confirm our findings.
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- Li, Fie, et al.
(author)
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Synthesis, structure and catalytic property of an iron(II) complex with an N4O2 ligand for alkane oxidation
- 2006
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In: Wuji huaxue xuebao. - 1001-4861. ; 22:10, s. 1899-1904
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Journal article (peer-reviewed)abstract
- Two iron(II) complexes [Fe(tpdoen)](FeCl4)Cl (2, tpdoen=NN-bis(2-pyridylmethoxyethyl)-N-(2-pyridylmethyl)amine) and [Fe(tpdoen)](ClO4)(2) (3) with an N4O2 ligand containing two potentially pi-coordinate oxygen atoms were synthesized as functional models of non-heme iron oxygenases. The X-ray crystal structure analysis corroborated that complex 3 possesses a significantly distorted six-coordinate pseudooctahedral configuration, in which all six heteroatoms (N4O2) coordinate to the iron center. The catalytic property of complex 3 for alkane oxidation were explored using H2O2, TBHP and mCPBA as oxidants in the presence of excess substrates under mild conditions. When cyclohexane oxidation process was monitored by UV-Vis spectra using H2O2 as oxidant at 0 degrees C, a short-life band appeared at ca 550 nm, which is attributed to the in-situ Fe(III)-OOH species.
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- Liu, Haibin, et al.
(author)
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Asymmetric oxidation of sulfides with hydrogen peroxide catalyzed by a vanadium complex of a new chiral NOO-ligand
- 2009
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In: Catalysis communications. - : Elsevier BV. - 1566-7367 .- 1873-3905. ; 11:4, s. 294-297
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Journal article (peer-reviewed)abstract
- A new chiral NOO-tridentate ligand (8R)-2-(2-hydroxyphenyl)-4-methyl-5,6,7.8-tetrahydro-quinolin-8-ol (1) bearing a rigid tetrahydroquinoline framework was prepared and applied in the vanadium-catalyzed asymmetric oxidation of aryl methyl sulfides with H2O2 as oxidant. Less toxic acetone was found to be the proper solvent for the enantioselective oxidation of sulfides. Under the optimal condition, the asymmetric oxidation of aryl methyl sulfides in acetone catalyzed by VO(acac)(2)/1 at 0 degrees C gives good to high yields (80-95%) of sulfoxides with enantioselectivity up to 77% ee.
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