| 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. |
- Jiang, Y, et al.
(författare)
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Falls and Fall-Related Consequences among Older People Living in Long-Term Care Facilities in a Megacity of China
- 2020
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Ingår i: Gerontology. - : S. Karger AG. - 1423-0003 .- 0304-324X. ; 66:6, s. 523-531
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Tidskriftsartikel (refereegranskat)abstract
- <b><i>Introduction:</i></b> Falls are currently the top safety problem in long-term care facilities (LTCFs) in China. Due to the increasing number of residents living in LTCFs, more evidence is needed to give a foundation for fall prevention. <b><i>Objective:</i></b> This study aimed to explore the epidemiological characteristics of falls in LTCFs in central Shanghai. <b><i>Methods:</i></b> The study was conducted in 21 LTCFs in a central district in Shanghai, with a capacity of 3,065 residents. A two-stage sampling method was applied in participant recruitment. Falls were recorded by LTCF staff over a 12-month period. Details of falls were obtained by face-to-face interviews. The χ<sup>2</sup> test was used in data analyses. <b><i>Results:</i></b> The incidence of falls was 13.5%; 64.0% falls resulted in injuries, with 32.0% involving fractures. Women had a significantly higher incidence of injurious falls than men (χ<sup>2</sup> = 4.066, <i>p</i> = 0.044). Residents aged 80–89 years or in level 1 care had the highest incidence of falls with severe consequences. The incidence of falls was significantly higher at small- or medium-sized LTCFs, public LTCFs, and LTCFs with higher environmental risk levels compared to their counterparts. Most falls occurred when walking on a flat floor (28.9%) and rising up or sitting down (24.0%); 40.9% occurred during the night. Of those injured, 54.8% were treated in hospitals, and only 53.7% completely recovered. <b><i>Conclusions:</i></b> Though the average incidence of falls in LTCFs in Shanghai was relatively low, great variation was observed between LTCFs, and severe consequences occurred frequently. Fall prevention programmes should be evidence-based with applicable devices and individualized care services and supports. The roles of personal and institutional factors on falls warrant further study.
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| 3. |
- Cao, Wei, et al.
(författare)
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Self-Assembly of Large Magnetic Nanoparticles in Ultrahigh Molecular Weight Linear Diblock Copolymer Films
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 12:6, s. 7557-7564
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Tidskriftsartikel (refereegranskat)abstract
- The development of diblock copolymer (DBC) nanocomposite films containing magnetic nanoparticles (NPs) with diameters (D) over 20 nm is a challenging task. To host large iron oxide NPs (Fe3O4, D = 27 +/- 0.6 nm), an ultrahigh molecular weight (UHMW) linear DBC polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) is used as a template in the present work. Due to hydrogen bonding between the carboxylic acid ligands of the NPs and the ester groups in PMMA, the NPs show an affinity to the PMMA block. The localization of the NPs inside the DBC is investigated as a function of the NP concentration. At low NP concentrations, NPs are located preferentially at the interface between PS and PMMA domains to minimize the interfacial tension caused by the strong segregation strength of the UHMW DBC. At high NP concentrations (>= 10 wt %), chain-like NP aggregates (a head-to-tail orientation) are observed in the PMMA domains, resulting in a change of the morphology from sphere to ellipsoid for part of the PMMA domains. Magnetic properties of the hybrid films are probed via superconducting quantum interference device magnetometry. All hybrid films show ferrimagnetism and are promising for potential applications in magnetic data storage.
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| 4. |
- Cheng, Yirui, et al.
(författare)
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Comparison of serum exosome isolation methods on co-precipitated free microRNAs.
- 2020
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Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Exosomes are nano-sized extracellular vesicles containing different biomolecules such as proteins and microRNAs (miRNAs) that mediate intercellular communication. Recently, numerous studies have reported the important functions of exosomal miRNAs in disease development and the potential clinical application as diagnostic biomarkers. Up to now, the most commonly used methods to extract exosomes are ultracentrifugation (UC) and precipitation-based commercial kit (e.g., ExoQuick). Generally, both UC and ExoQuick method could co-isolate contaminating proteins along with exosomes, with the UC method yielding even purer exosomes than ExoQuick. However, the comparison of these two methods on co-precipitated free miRNAs is still unknown.Methods: In this study, we isolated exosomes from the human serum with exogenously added cel-miR-39 by UC and ExoQuick and compared the proportion of cel-miR-39 co-precipitated with exosomes extracted by these two methods.Results: Using exogenous cel-miR-39 as free miRNAs in serum, we concluded that ExoQuick co-isolates a small proportion of free miRNAs while UC hardly precipitates any free miRNAs. We also found that incubation at 37 °C for 1 h could decrease the proportion of free miRNAs, and exosomal miRNAs like miR-126 and miR-152 also decreased when RNase A was used. In conclusion, our findings provide essential information about the details of serum exosome isolation methods for further research on exosomal miRNAs.
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| 5. |
- Granadillo, JL, et al.
(författare)
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Pathogenic variants in TNRC6B cause a genetic disorder characterised by developmental delay/intellectual disability and a spectrum of neurobehavioural phenotypes including autism and ADHD
- 2020
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Ingår i: Journal of medical genetics. - : BMJ. - 1468-6244 .- 0022-2593. ; 57:10, s. 717-724
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Tidskriftsartikel (refereegranskat)abstract
- Rare variants in hundreds of genes have been implicated in developmental delay (DD), intellectual disability (ID) and neurobehavioural phenotypes. TNRC6B encodes a protein important for RNA silencing. Heterozygous truncating variants have been reported in three patients from large cohorts with autism, but no full phenotypic characterisation was described.MethodsClinical and molecular characterisation was performed on 17 patients with TNRC6B variants. Clinical data were obtained by retrospective chart review, parent interviews, direct patient interaction with providers and formal neuropsychological evaluation.ResultsClinical findings included DD/ID (17/17) (speech delay in 94% (16/17), fine motor delay in 82% (14/17) and gross motor delay in 71% (12/17) of subjects), autism or autistic traits (13/17), attention deficit and hyperactivity disorder (ADHD) (11/17), other behavioural problems (7/17) and musculoskeletal findings (12/17). Other congenital malformations or clinical findings were occasionally documented. The majority of patients exhibited some dysmorphic features but no recognisable gestalt was identified. 17 heterozygous TNRC6B variants were identified in 12 male and five female unrelated subjects by exome sequencing (14), a targeted panel (2) and a chromosomal microarray (1). The variants were nonsense (7), frameshift (5), splice site (2), intragenic deletions (2) and missense (1).ConclusionsVariants in TNRC6B cause a novel genetic disorder characterised by recurrent neurocognitive and behavioural phenotypes featuring DD/ID, autism, ADHD and other behavioural abnormalities. Our data highly suggest that haploinsufficiency is the most likely pathogenic mechanism. TNRC6B should be added to the growing list of genes of the RNA-induced silencing complex associated with ID/DD, autism and ADHD.
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| 6. |
- Li, Zhao, et al.
(författare)
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Minimum carbon uptake controls the interannual variability of ecosystem productivity in tropical evergreen forests
- 2020
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Ingår i: Global and Planetary Change. - : Elsevier BV. - 0921-8181. ; 195
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Tidskriftsartikel (refereegranskat)abstract
- Tropical evergreen forests contribute an important part to the interannual variability (IAV) of the global terrestrial gross primary productivity (GPP). Due to its year-round growing-season, high minimum carbon uptake (GPPmin) and dry season greening-up, the key processes driving the GPP variability across seasonal to interannual scale are still in debate. Here, we analyzed the time-series of FLUXCOM GPP (1980–2013), sun-induced fluorescence (SIF; 2001–2013) and site-level GPP measurements in three tropical evergreen forests regions (i.e., Amazon, Africa, and Southeast Asia). We decomposed the annual accumulated GPP into the basic and recurrent GPP, which represent the accumulated minimum and seasonal vegetation productivity, respectively. Then we quantified the proportion of each component and estimated the contribution to the IAV of GPP. We find that the basic GPP overwhelmed the recurrent GPP with the averaging ratio of 4.2:1 across the global tropical regions, and dominated the IAV of annual total GPP in 83.7% of the tropical evergreen forest areas. The high contribution of the basic GPP resulted from the great sensitivity of GPPmin to rainfall changes among years. The decomposition of the basic and recurrent GPP sheds new light on the understanding of tropical GPP variability in responding to climate change at seasonal and annual scale. Our study highlights the critical role of the GPPmin in shaping temporal dynamics of the annual GPP in tropical forests and emphasizes the importance of managing tropical forest of the shifting periods between wet-dry seasons in global tropical regions.
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| 7. |
- Song, Dan-Na, et al.
(författare)
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Luminescent Thermochromic Silver Iodides as Wavelength-Dependent Thermometers
- 2020
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 59:18, s. 13067-13077
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Tidskriftsartikel (refereegranskat)abstract
- Luminescent thermochromic materials with a dramatic shift of emission band under different temperatures are highly desirable in temperature sensing fields. However, the design of the synthesis of such compounds remains a great challenge. In this work, two new luminescent thermochromic silver iodides, (emIm)Ag3I4 (1) and (emIm)Ag2I3 (2) (emIm = 1-ethyl-3-methyl imidazole), have been synthesized under solvothermal conditions. Compound 1 features a [Ag3I4]− anionic layer, while compound 2 possesses an infinite [Ag2I3]− chain structure, both of which are charge balanced by emIm+ cations. Particularly, they display luminescent thermochromism with a significant wavelength shift of emission maximum with temperature change. They represent rare examples of infinite layered or chain silver iodides that show luminescent thermochromism. Furthermore, the results indicate that compounds 1 and 2 are promising wavelength-dependent luminescent thermometers.
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| 8. |
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