By genetically testing nearly 1,000 embryos, scientists have provided the most detailed analysis of embryo fate following human in vitro fertilization.
Oct 1, 2023
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Natural health products and phytomedicines (plant-based medicines) are used in many countries as the first choice of treatment. This market represents a significant proportion of the total market for health products, particularly ...
Jul 27, 2023
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Bandages infused with casein, a protein that occurs naturally in cow's milk, significantly improved wound healing in rats compared to those in control groups, according to a new study by UCL researchers.
Jul 26, 2023
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Ultrafine magnetic iron oxide particles smaller than 500 nanometers are prevalent in air pollution on the London Underground, according to a study published in Scientific Reports. The authors propose that improved air pollution ...
Dec 15, 2022
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From a scientist's laptop to the syringe used to inject the UK's first COVID vaccine dose, an exhibition that opened Wednesday in London recounts the quest to produce a coronavirus jab through objects.
Nov 30, 2022
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There are now high levels of sweet and fruit-flavored chemicals likely to appeal to young people in e-cigarette liquids ostensibly marketed as "tobacco-flavored," compared with a decade ago, finds research published today ...
Nov 3, 2022
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Electronic cigarettes, or ECs, contain nicotine, solvents, and flavor chemicals, and are especially popular among young adults. In 2020, the Food and Drug Administration, or FDA, banned cartridge-based flavored EC pods, but ...
Aug 2, 2022
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Sweating it out through exercise may be a New Year's resolution but it could also help to provide new insights into the state of your health, according to new sensing technology being developed at Simon Fraser University.
Jan 11, 2022
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Spinal cord injuries can be life-changing and alter many important neurological functions. Unfortunately, clinicians have relatively few tools to help patients regain lost functions.
Mar 9, 2021
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Washington DC has joined the states of New York and California in suing Juul labs, the United States' largest electronic cigarette manufacturer, for targeting youngsters with its marketing campaigns.
Nov 27, 2019
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In chemistry, the empirical formula of a chemical compound is a simple expression of the relative numbers of each type of atom in it, or the simplest whole number ratio of atoms of each element present in a compound. An empirical formula makes no reference to isomerism, structure, or absolute number of atoms. The empirical formula is used as standard for most ionic compounds, such as CaCl2, and for macromolecules, such as SiO2. The term empirical refers to the process of elemental analysis, a technique of analytical chemistry used to determine the relative amounts of each element in a chemical compound.
In contrast, the molecular formula identifies a numbers of each type of atom in a molecule, and the structural formula also shows the structure of the molecule.
For example, the chemical compound n-hexane has the structural formula CH3CH2CH2CH2CH2CH3, which shows that it has 6 carbon atoms arranged in a straight chain, and 14 hydrogen atoms. Hexane's molecular formula is C6H14, and its empirical formula is C3H7, showing a C:H ratio of 3:7. Different compounds can have the same empirical formula. For example, glucose, formaldehyde and acetic acid have the same empirical formula, CH2O. This is the actual chemical formula for formaldehyde, but acetic acid has double the number of atoms and glucose has six times the number of atoms.
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