SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Formula

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BODIPY 505/515, a lipophilic bright green fluorescent dye was tested for lipid detection in the microalga Tetraselmis subcordiformis. A concentration of 0.28μgml(-1) and staining for 6min was optimal. Lipid bodies stained with BODIPY505/515 had a characteristic green fluorescence. Their volumes were determined using the sphere volume formula. Lipid accumulation under different nitrogen concentrations was analyzed. With an increase in NaNO(3) concentration from 0 to 240mg L(-1), the maximum algal concentration increased from 8.23±0.62 (×10(5) cells ml(-1)) to 1.61±0.13 (×10(6) cellsml(-1)), while the maximum volume of intracellular neutral lipid decreased from 9.78±1.77 μm(3)cell(-1) to 6.00±0.59μm(3)cell(-1). A comparison of the lipid contents measured by BODIPY 505/515 staining and the gravimetric method showed a positive correlation coefficient of R(2)=0.93. BODIPY 505/515 staining is a promising method in lipid quantitation in T. subcordiformis.

Concepts: Oxygen, Volume, Spearman's rank correlation coefficient, Correlation and dependence, Pearson product-moment correlation coefficient, Dyes, Sphere, Formula

27

BACKGROUND: Our aim is to implement a simple, rapid, and reliable method using computed tomography perfusion imaging and clinical judgment to target patients for reperfusion therapy in the hyper-acute stroke setting. We introduce a novel formula (1-infarct volume [CBV]/penumbra volume [MTT]× 100%) to quantify mismatch percentage. METHODS: Twenty patients with anterior circulation strokes who underwent CT perfusion and received intravenous tissue plasminogen activator (IV tPA) were analyzed retrospectively. Nine blinded viewers determined volume of infarct and ischemic penumbra using the ABC/2 method and also the mismatch percentage. RESULTS: Interrater reliability using the volumetric formula (ABC/2) was very good (intraclass correlation [ICC]= .9440 and ICC = .8510) for hemodynamic parameters infarct (CBV) and penumbra (MTT). ICC coefficient using the mismatch formula (1-MTT/CBV × 100%) was good (ICC of .635). CONCLUSIONS: The ABC/2 method of volume estimation on CT perfusion is a reliable and efficient approach to determine infarct and penumbra volumes. The 1-CBV/MTT × 100% formula produces a mismatch percentage assisting providers in communicating the proportion of salvageable brain and guides therapy in the setting of patients with unclear time of onset with potentially salvageable tissue who can undergo mechanical retrieval or intraarterial thrombolytics.

Concepts: Volume, Stroke, Thermodynamics, Tissue plasminogen activator, Thrombolysis, Plasmin, Inter-rater reliability, Formula

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Amino-acid-based formulas (AAFs) are recommended for children with cow’s milk protein allergy (CMPA) failing to respond to extensively hydrolyzed formulas (eHFs).

Concepts: Protein, Nutrition, Polymer, Milk, Cattle, Formula, Milk allergy

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The appearance of being scientific can increase persuasiveness. Even trivial cues can create such an appearance of a scientific basis. In our studies, including simple elements, such as graphs (Studies 1-2) or a chemical formula (Study 3), increased belief in a medication’s efficacy. This appears to be due to the association of such elements with science, rather than increased comprehensibility, use of visuals, or recall. Belief in science moderates the persuasive effect of graphs, such that people who have a greater belief in science are more affected by the presence of graphs (Study 2). Overall, the studies contribute to past research by demonstrating that even trivial elements can increase public persuasion despite their not truly indicating scientific expertise or objective support.

Concepts: Mathematics, Epistemology, Science, Nature, Regulatory Focus Theory, Society, Formula, Chemical formula

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The calculation of the volume ratio between the hernia sac and the abdominal cavity of incisional hernias is based on tomographic sections as well as the mathematical formula of the volume of the ellipsoid, which allows determining whether this is a giant hernia or there is a “loss of domain”. As the images used are not exact geometric figures, the study of the volume of two solid organs of Wistar rats was performed to validate these calculations.

Concepts: Mathematics, Volume, Geometry, Hernia, Algebra, Calculation, Formula, Spreadsheet

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To evaluate the accuracy of the optical coherence tomography-based (OCT formula) and Barrett True K (True K) intraocular lens (IOL) calculation formulas in eyes with previous radial keratotomy (RK).

Concepts: Sample size, Optics, Visual perception, Lens, Presbyopia, Intraocular lens, Formula, Chemical formula

8

Drug safety precautions recommend monitoring of the corrected QT interval. To determine which QT correction formula to use in an automated QT-monitoring algorithm in our electronic medical record, we studied rate correction performance of different QT correction formulae and their impact on risk assessment for mortality.

Concepts: Pharmacology, Cardiology, QT interval, Adverse drug reaction, Formula

2

Glyphosate is an herbicide widely used in the world, being applied in several crops, among them soybeans. Recently, glyphosate and its metabolite aminomethylphosphonic acid (AMPA) have been identified as possible contributors to the emergence of various diseases such as autism, Parkinson’s and Alzheimer’s diseases, as well as cancer. The child population consuming cereal-based foods is the most exposed to the effects of pesticides because of their developmental phase and they have a higher food intake per kilogram of body weight than adults. The presence of glyphosate and AMPA residues in soy-based infant formulas was evaluated during the years 2012-2017, totalizing 105 analyzes carried out on 10 commercial brands from different batches. Glyphosate and AMPA were determined by liquid chromatography with fluorescence detection after derivatization reaction. The method was validated and showed accuracy and precision with a limit of quantification (LOQ) of 0.02 mg kg-1. Among those samples that contained levels above the LOQ, the variation of glyphosate residues was from 0.03 mg kg-1 to 1.08 mg kg-1 and for AMPA residues was from 0.02 mg kg-1 to 0.17 mg kg-1. This is the first scientific communication about glyphosate and AMPA contamination in soy-based infant formula in Brazil, The study was conducted under good laboratory practice (GLP) and supported by good scientific practice.

Concepts: Alzheimer's disease, Measurement, Food, Science, Analytical chemistry, Accuracy and precision, Good Laboratory Practice, Formula

2

Recently, the role of using hydrolyzed formula for the prevention of allergic disease has been questioned. However, not all hydrolyzed formulas are equal. The efficacy of each hydrolyzed formula should be established separately. We updated evidence on the effectiveness of using partially hydrolyzed 100% whey formula (pHF), manufactured by a single manufacturer, for reducing the risk of eczema and allergy in healthy infants at high risk for allergy.

Concepts: Epidemiology, Asthma, Allergy, Food allergy, Eczema, Traditional Chinese medicine, Formula, Allergic inflammation

2

In the noisy cellular environment, gene products are subject to inherent random fluctuations in copy numbers over time. How cells ensure precision in the timing of key intracellular events despite such stochasticity is an intriguing fundamental problem. We formulate event timing as a first-passage time problem, where an event is triggered when the level of a protein crosses a critical threshold for the first time. Analytical calculations are performed for the first-passage time distribution in stochastic models of gene expression. Derivation of these formulas motivates an interesting question: Is there an optimal feedback strategy to regulate the synthesis of a protein to ensure that an event will occur at a precise time, while minimizing deviations or noise about the mean? Counterintuitively, results show that for a stable long-lived protein, the optimal strategy is to express the protein at a constant rate without any feedback regulation, and any form of feedback (positive, negative, or any combination of them) will always amplify noise in event timing. In contrast, a positive feedback mechanism provides the highest precision in timing for an unstable protein. These theoretical results explain recent experimental observations of single-cell lysis times in bacteriophage [Formula: see text] Here, lysis of an infected bacterial cell is orchestrated by the expression and accumulation of a stable [Formula: see text] protein up to a threshold, and precision in timing is achieved via feedforward rather than feedback control. Our results have broad implications for diverse cellular processes that rely on precise temporal triggering of events.

Concepts: DNA, Gene, Bacteria, Control theory, Feedback, Negative feedback, Formula, Positive feedback