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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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- Santigosa-Murillo, Elia, et al.
(författare)
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A novel integrated platform enabling simultaneous microextraction and chemical analysis on-chip
- 2023
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Ingår i: Microchemical journal (Print). - 0026-265X .- 1095-9149. ; 193
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Tidskriftsartikel (refereegranskat)abstract
- The nature and size of biological, pharmaceutical or environmental analytes complicates their extraction and detection outside of laboratories and near the site of interest by the current chromatographic methods because they require the combination of bulky extraction and detection methods. In order to solve this inefficient centralized control, a ground-breaking and miniaturized proof of concept platform is developed in this work. The platform integrates for the very first time an electro-membrane extraction process and an accurate analyte quantification method in the same device, by using electrochemical impedance spectroscopy (EIS) as analytical technique. The microfluidic flow cell, including the microfluidic components, is fabricated in polymeric materials by rapid prototyping techniques. It comprises a four-electrode platinum thin-film chip that enables the control of the microextraction and the full characterization of the process, i.e., extraction efficiency determination, at the same time. The microfluidic system has been simulated by using computational tools, enabling an accurate prediction of the effect of the different experimental conditions in the microextraction efficiency. The platform has been validated in the microextraction of the nonsteroidal anti-inflammatory drug ketoprofen in a range from 0.5 ppm to 6 ppm. The predicted microextraction efficiency values obtained by EIS were compared with those calculated from the high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD), showing an excellent agreement. This validates the high potential of this integrated and miniaturized platform for the simultaneous extraction by electro-membrane and also the analysis within the platform, solving one of the of most important limitations of current systems.
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- Delrez, Laetitia, et al.
(författare)
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Transit detection of the long-period volatile-rich super-Earth nu(2) Lupi d with CHEOPS
- 2021
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Ingår i: Nature Astronomy. - : Springer Science and Business Media LLC. - 2397-3366. ; :5, s. 775-787
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Tidskriftsartikel (refereegranskat)abstract
- Exoplanets transiting bright nearby stars are key objects for advancing our knowledge of planetary formation and evolution. The wealth of photons from the host star gives detailed access to the atmospheric, interior and orbital properties of the planetary companions. nu(2) Lupi (HD 136352) is a naked-eye (V = 5.78) Sun-like star that was discovered to host three low-mass planets with orbital periods of 11.6, 27.6 and 107.6 d via radial-velocity monitoring(1). The two inner planets (b and c) were recently found to transit(2), prompting a photometric follow-up by the brand new Characterising Exoplanets Satellite (CHEOPS). Here, we report that the outer planet d is also transiting, and measure its radius and mass to be 2.56 +/- 0.09 R-circle plus and 8.82 +/- 0.94 M-circle plus, respectively. With its bright Sun-like star, long period and mild irradiation (similar to 5.7 times the irradiation of Earth), nu(2) Lupi d unlocks a completely new region in the parameter space of exoplanets amenable to detailed characterization. We refine the properties of all three planets: planet b probably has a rocky mostly dry composition, while planets c and d seem to have retained small hydrogen-helium envelopes and a possibly large water fraction. This diversity of planetary compositions makes the nu(2) Lupi system an excellent laboratory for testing formation and evolution models of low-mass planets.
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- Dietvorst, Jiri, et al.
(författare)
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Bacteria Detection at a Single-Cell Level through a Cyanotype-Based Photochemical Reaction
- 2022
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 94:2, s. 787-792
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Tidskriftsartikel (refereegranskat)abstract
- The detection of living organisms at very low concentrations is necessary for the early diagnosis of bacterial infections, but it is still challenging as there is a need for signal amplification. Cell culture, nucleic acid amplification, or nano-structure-based signal enhancement are the most common amplification methods, relying on long, tedious, complex, or expensive procedures. Here, we present a cyanotype-based photochemical amplification reaction enabling the detection of low bacterial concentrations up to a single-cell level. Photocatalysis is induced with visible light and requires bacterial metabolism of iron-based compounds to produce Prussian Blue. Bacterial activity is thus detected through the formation of an observable blue precipitate within 3 h of the reaction, which corresponds to the concentration of living organisms. The short time-to-result and simplicity of the reaction are expected to strongly impact the clinical diagnosis of infectious diseases.
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- Farrell, M, et al.
(författare)
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Increased Prevalence of Rare Copy Number Variants in Treatment-Resistant Psychosis
- 2023
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Ingår i: Schizophrenia bulletin. - : Oxford University Press (OUP). - 1745-1701 .- 0586-7614. ; 49:4, s. 881-892
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundIt remains unknown why ~30% of patients with psychotic disorders fail to respond to treatment. Previous genomic investigations of treatment-resistant psychosis have been inconclusive, but some evidence suggests a possible link between rare disease-associated copy number variants (CNVs) and worse clinical outcomes in schizophrenia. Here, we identified schizophrenia-associated CNVs in patients with treatment-resistant psychotic symptoms and then compared the prevalence of these CNVs to previously published schizophrenia cases not selected for treatment resistance.MethodsCNVs were identified using chromosomal microarray (CMA) and whole exome sequencing (WES) in 509 patients with treatment-resistant psychosis (a lack of clinical response to ≥3 adequate antipsychotic medication trials over at least 5 years of psychiatric hospitalization). Prevalence of schizophrenia-associated CNVs in this sample was compared to that in a previously published large schizophrenia cohort study.ResultsIntegrating CMA and WES data, we identified 47 cases (9.2%) with at least one CNV of known or possible neuropsychiatric risk. 4.7% (n = 24) carried a known neurodevelopmental risk CNV. The prevalence of well-replicated schizophrenia-associated CNVs was 4.1%, with duplications of the 16p11.2 and 15q11.2-q13.1 regions, and deletions of the 22q11.2 chromosomal region as the most frequent CNVs. Pairwise loci-based analysis identified duplications of 15q11.2-q13.1 to be independently associated with treatment resistance.ConclusionsThese findings suggest that CNVs may uniquely impact clinical phenotypes beyond increasing risk for schizophrenia and may potentially serve as biological entry points for studying treatment resistance. Further investigation will be necessary to elucidate the spectrum of phenotypic characteristics observed in adult psychiatric patients with disease-associated CNVs.
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- García-Vilana, Silvia, et al.
(författare)
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Study of risk factors for injuries due to cardiopulmonary resuscitation with special focus on the role of the heart : A machine learning analysis of a prospective registry with multiple sources of information (ReCaPTa Study)
- 2024
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Ingår i: Resuscitation Plus. - 2666-5204. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Background: The study of thoracic injuries and biomechanics during CPR requires detailed studies that are very scarce. The role of the heart in CPR biomechanics has not been determined. This study aimed to determine the risk factors importance for serious ribcage damage due to CPR. Methods: Data were collected from a prospective registry of out-of-hospital cardiac arrest between April 2014 and April 2017. This study included consecutive out-of-hospital CPR attempts undergoing an autopsy study focused on CPR injuries. Cardiac mass ratio was defined as the ratio of real to expected heart mass. Pearson's correlation coefficient was used to select clinically relevant variables and subsequently classification tree models were built. The Gini index was used to determine the importance of the associated serious ribcage damage factors. The LUCAS® chest compressions device forces and the cardiac mass were analyzed by linear regression. Results: Two hundred CPR attempts were included (133 manual CPR and 67 mechanical CPR). The mean age of the sample was 60.4 ± 13.5, and 56 (28%) were women. In all, 65.0% of the patients presented serious ribcage damage. From the classification tree build with the clinically relevant variables, age (0.44), cardiac mass ratio (0.26), CPR time (0.22), and mechanical CPR (0.07), in that order, were the most influential factors on serious ribcage damage. The chest compression forces were greater in subjects with higher cardiac mass. Conclusions: The heart plays a key role in CPR biomechanics being cardiac mass ratio the second most important risk factor for CPR injuries.
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| 10. |
- Iyengar, Sharath Narayana, et al.
(författare)
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Rapid detection of viable bacteria in whole blood for early sepsis diagnosis and suseptibility testing
- 2021
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Ingår i: Proceedings MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. ; , s. 791-792
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Konferensbidrag (refereegranskat)abstract
- Sepsis is a serious medical condition characterized by a whole-body inflammatory state caused by infection. Here, we present a sepsis method for rapid detection of bacteria from whole blood in less than 5h, combining selective blood cell lysis and a sensitive colorimetric based detection method. Selective cell lysis buffer allows selective rupture of blood cells (5 min), while maintaining bacteria 100% viable. Viable bacteria metabolically reduce iron (III) complexes, initiating a photo-catalytic cascade toward Prussian Blue formation visible to the naked eye. The method is finally validated for antibiotic susceptibility testing.
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