| 1. |
|
|
| 2. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
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.
|
|
| 3. |
- Liu, Shaohua, et al.
(författare)
-
Synthesis of chiral TiO2 nanofibre with electron transition-based optical activity
- 2012
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 3, s. 1215-
-
Tidskriftsartikel (refereegranskat)abstract
- The optical chirality induced at the absorption bands due to electronic exciton coupling of the transition dipole moments between chromophores in close proximity is ubiquitous in helical organic materials. However, inorganic materials with optical activity resulting from electronic transitions have not been explored. Here we report the synthesis of chiral TiO2 fibres via transcription of the helical structure of amino acid-derived amphiphile fibres through coordination bonding interactions between the organics and the TiO2 source. Upon calcination, the as-prepared amorphous TiO2 double-helical fibres with a pitch length of ~100 nm were converted to double-helical crystalline fibres with stacks of anatase nanocrystals in an epitaxial helical relationship. Both the amorphous and anatase crystalline helical TiO2 fibres exhibited optical response to circularly polarized light at the absorption edge around ~350 nm. This was attributed to the semiconductor TiO2-based electronic transitions from the valence band to the conduction band under an asymmetric electric field.
|
|
| 4. |
- Xu, Kangjun, et al.
(författare)
-
Association between serum vitamin B12 and risk of all-cause mortality in elderly adults : a prospective cohort study
- 2021
-
Ingår i: BMC Geriatrics. - : BioMed Central. - 1471-2318. ; 21:1
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Results from previous studies that linking vitamin B12 to risk of chronic diseases or mortality are inconsistent. We hereby explore the association between serum concentration of vitamin B12 and all-cause mortality risk in elderly adults.METHODS: Participants aged over 65 years in the Chinese Longitudinal Healthy Longevity Survey were included in present prospective cohort study. Serum vitamin B12 was assessed at the 2011-2012 and 2014 wave, respectively. Participants were divided into three groups based on two cut-off points - 10th and 90th percentiles of vitamin B12 concentrations - in the whole population. Cox regression model was used to calculate the hazard ratio (HR) and 95 % confidence intervals (95 % CIs), and restricted cubic spline function was further modelled to investigate their dose-response associations.RESULTS: Among 2,086 participants [mean ± SD: 87.74 ± 11.24 years, 908 (43.53 %) males], 943 (45.21 %) died during an average follow-up of 3.34 (SD: 1.63) years. Comparing with participants with middle concentration of serum vitamin B12, participants with high concentration had an increased risk of all-cause mortality [HR (95 %CIs): 1.30 (1.03-1.64)], whereas participants with low concentration had an insignificantly decreased risk of all-cause mortality (0.96, 0.76-1.20). The positive association between high concentration of serum vitamin B12 and all-cause mortality was also observed among the male and in a series of sensitivity analyses. In the dose-response analysis, a J-shape pattern was observed, but the non-linear association was only significant in males (Pnon-linearity = 0.0351).CONCLUSIONS: High concentration of serum vitamin B12 was associated with an increased risk of all-cause mortality in a J-shaped pattern. The precise mechanisms underlying the association remain to be explored.
|
|
| 5. |
- Zhang, Xueli, et al.
(författare)
-
CBD2 : A functional biomarker database for colorectal cancer
- 2024
-
Ingår i: iMeta. - : John Wiley & Sons. - 2770-5986 .- 2770-596X. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- The rapidly evolving landscape of biomarkers for colorectal cancer (CRC) necessitates an integrative, updated repository. In response, we constructed the Colorectal Cancer Biomarker Database (CBD), which collected and displayed the curated biomedicine information for 870 CRC biomarkers in the previous study. Building on CBD, we have now developed CBD2, which includes information on 1569 newly reported biomarkers derived from different biological sources (DNA, RNA, protein, and others) and clinical applications (diagnosis, treatment, and prognosis). CBD2 also incorporates information on nonbiomarkers that have been identified as unsuitable for use as biomarkers in CRC. A key new feature of CBD2 is its network analysis function, by which users can investigate the visible and topological network between biomarkers and identify their relevant pathways. CBD2 also allows users to query a series of chemicals, drug combinations, or multiple targets, to enable multidrug, multitarget, multipathway analyses, toward facilitating the design of polypharmacological treatments for CRC. CBD2 is freely available at http://www.eyeseeworld.com/cbd.
|
|
| 6. |
- An, Rui, et al.
(författare)
-
Photostability and Photodegradation Processes in Colloidal CsPbI3 Perovskite Quantum Dots
- 2018
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 10:45, s. 39222-39227
-
Tidskriftsartikel (refereegranskat)abstract
- All-inorganic CsPbI3 perovskite quantum dots (QDs) have attracted intense attention for their successful application in photovoltaics (PVs) and optoelectronics that are enabled by their superior absorption capability and great photoluminescence (PL) properties. However, their photostability remains a practical bottleneck and further optimization is highly desirable. Here, we studied the photostability of as-obtained colloidal CsPbI3 QDs suspended in hexane. We found that light illumination does induce photodegradation of CsPbI3 QDs. Steady-state spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and transient absorption spectroscopy verified that light illumination leads to detachment of the capping agent, collapse of the CsPbI3 QD surface, and finally aggregation of surface Pb0. Both dangling bonds containing surface and Pb0 serve as trap states causing PL quenching with a dramatic decrease of PL quantum yield. Our work provides a detailed insight about the correlation between the structural and photophysical consequences of the photodegradation process in CsPbI3 QDs and may lead to the optimization of such QDs toward device applications.
|
|
| 7. |
- Benatar, Michael, et al.
(författare)
-
Design of a randomized, placebo-controlled, phase 3 trial of tofersen initiated in clinically presymptomatic SOD1 variant carriers : the Atlas study
- 2022
-
Ingår i: Neurotherapeutics. - : Springer. - 1933-7213 .- 1878-7479. ; 19, s. 1248-1258
-
Tidskriftsartikel (refereegranskat)abstract
- Despite extensive research, amyotrophic lateral sclerosis (ALS) remains a progressive and invariably fatal neurodegenerative disease. Limited knowledge of the underlying causes of ALS has made it difficult to target upstream biological mechanisms of disease, and therapeutic interventions are usually administered relatively late in the course of disease. Genetic forms of ALS offer a unique opportunity for therapeutic development, as genetic associations may reveal potential insights into disease etiology. Genetic ALS may also be amenable to investigating earlier intervention given the possibility of identifying clinically presymptomatic, at-risk individuals with causative genetic variants. There is increasing evidence for a presymptomatic phase of ALS, with biomarker data from the Pre-Symptomatic Familial ALS (Pre-fALS) study showing that an elevation in blood neurofilament light chain (NfL) precedes phenoconversion to clinically manifest disease. Tofersen is an investigational antisense oligonucleotide designed to reduce synthesis of superoxide dismutase 1 (SOD1) protein through degradation of SOD1 mRNA. Informed by Pre-fALS and the tofersen clinical development program, the ATLAS study (NCT04856982) is designed to evaluate the impact of initiating tofersen in presymptomatic carriers of SOD1 variants associated with high or complete penetrance and rapid disease progression who also have biomarker evidence of disease activity (elevated plasma NfL). The ATLAS study will investigate whether tofersen can delay the emergence of clinically manifest ALS. To our knowledge, ATLAS is the first interventional trial in presymptomatic ALS and has the potential to yield important insights into the design and conduct of presymptomatic trials, identification, and monitoring of at-risk individuals, and future treatment paradigms in ALS.
|
|
| 8. |
- Cao, Yingying, et al.
(författare)
-
Screening of Alternative Solvent Ionic Liquids for Artemisinin : COSMO-RS Prediction and Experimental Verification
- 2021
-
Ingår i: Journal of Molecular Liquids. - : Elsevier. - 0167-7322 .- 1873-3166. ; 338
-
Tidskriftsartikel (refereegranskat)abstract
- Organic solvents are usually used to extract artemisinin from Artemisia annua L., and they can also be the solvents for the subsequent purification or derivatization to produce compounds with more efficient antimalarial effect. However, these solvents are volatile, explosive and toxic. The designable material ionic liquids (ILs) are alternative solvents to replace traditional ones. In this work, a reliable method for screening ILs with high solvation capability for artemisinin was developed. The infinite dilution activity coefficients of artemisinin in 903 ILs, composed by 43 cations and 21 anions, were calculated by COSMO-RS, and the results implied that the solubility of artemisinin in ILs mainly depends on the anions. Solubilities of artemisinin in 14 representative ILs were tested, and the results were in good accordance with those obtained in COSMO-RS calculation. The stability of artemisinin in some typical ILs was also studied, which indicated that this drug was stable in [EMIM][BF4], [EMIM][CF3Ac], [EMIM][NTF2], [BPY][NTF2], [EMIM][SCN], and [EMIM][Ac]. The excess enthalpy analysis demonstrated that artemisinin interacted with ILs mainly through hydrogen bond. Extraction of artemisinin using the optimal IL indicated that more artemisinin could be extracted from the leaves when compared with petroleum ether (254.73 mg/mol vs. 14.16 mg/mol), further verifying accuracy of the simulation results. Therefore, structures of ILs with high solvation capacity for artemisinin can be obtained by the COSMO-RS method.
|
|
| 9. |
- Chen, Yifeng, et al.
(författare)
-
Thermodynamic Study for Gas Absorption in Choline-2-pyrrolidine-carboxylic Acid + Polyethylene Glycol
- 2016
-
Ingår i: Journal of Chemical and Engineering Data. - : American Chemical Society (ACS). - 0021-9568 .- 1520-5134. ; 61:10, s. 3428-3437
-
Tidskriftsartikel (refereegranskat)abstract
- The solubility of pure CO2, CH4, and N2 in the mixture of choline-2-pyrrolidine carboxylic acid ([Cho][Pro]) and polyethylene glycol (PEG200) (mass ratio = 1:2) was measured experimentally at temperatures from 308.15 to 338.15 K and pressures up to 28 bar, in which [Cho][Pro] is an ionic liquid and PEG200 is a cosolvent with the purpose to decrease the viscosity. It was found that [Cho][Pro]/PEG200 showed a good selectivity for CO2/CH4 and CO2/N2 separation. The measured experimental data points from this work and others were further used to estimate the thermodynamic properties including the Henry's law constants for the gases in [Cho][Pro]/PEG200, the equilibrium constant for the reaction between CO2 and [Cho][Pro], the CO2 absorption enthalpy in [Cho][Pro]/PEG200, and so forth. The consistent results of the CO2 absorption enthalpy at infinite dilution prove the reliability of the thermodynamic properties obtained in this work. The thermodynamic properties of [Cho][Pro]/PEG200 were further compared with other three typical absorbents, and the absorption enthalpy is nearly half of that for 30 wt % MEA aqueous solution. At the same time, the theoretical amount of absorbents needed for [Cho][Pro]/PEG200 is much lower than that of H2O scrubbing. This shows that [Cho][Pro]/PEG200 is a promising absorbent
|
|
| 10. |
- Liu, Hailong, et al.
(författare)
-
Effect of the Sliding Velocity on the Size and Amount of Airborne Wear Particles Generated from Dry Sliding Wheel-Rail Contacts
- 2016
-
Ingår i: Tribology letters. - : Springer Science and Business Media LLC. - 1023-8883 .- 1573-2711. ; 63:3
-
Tidskriftsartikel (refereegranskat)abstract
- A set of frictional experiments have been conducted on a pin-on-disk apparatus to investigate the effect of the sliding velocity on airborne wear particles generated from dry sliding wheel-rail contacts. The size and the amount of generated particles were acquired by using particle counter instruments during the whole test period. After the completion of tests, the morphology and chemical compositions of pin worn surfaces and collected particles were analyzed by using scanning electron microscopy combined with an energy-dispersive X-ray analysis system. The results show that the total particle number concentration increases dramatically with an increased sliding velocity from 0.1 to 3.4 m/s. Moreover, the fine and ultrafine particles (<1 mu m) dominates the particle generation mode in the case of a high sliding velocity (1.2 and 3.4 m/s). The contact temperature variation is observed to be closely related to the size mode of the particle generation. In addition, the sliding velocity is found to influence the active wear. Correspondingly, an oxidative wear is identified as the predominant wear mechanisms for cases with high sliding velocities (1.2 and 3.4 m/s). This produces a substantial number of iron oxide-containing particles (<1 mu m) and reduces the wear rate to a relative low level (the wear rate for a 3.4 m/s sliding velocity is 4.5 % of that for a 0.4 m/s sliding velocity).
|
|
