Also known as: AT^
AT has various meanings in the Chemistry category. Discover the full forms, definitions, and usage contexts of AT in Chemistry.
Astatine, symbolized as At, is a rare and radioactive element in the halogen group of the periodic table, with atomic number 85. It is the heaviest known halogen and exists in nature only as a decay product of heavier elements, making it one of the rarest naturally occurring elements on Earth. Due to its extreme rarity and radioactivity, astatine has limited applications, primarily in scientific research and potential cancer treatment through targeted alpha therapy.
The element's properties are largely inferred from its position in the periodic table and limited experimental data, as its high radioactivity and short half-life of its isotopes make study challenging. Astatine's potential in medicine lies in its ability to emit alpha particles, which can be targeted to destroy cancer cells with minimal damage to surrounding healthy tissue. However, the practical use of astatine is hindered by the difficulties in its production and handling.
ChemistryAdditive templates refer to a method or framework used in Chemistry for the systematic addition of components to create complex molecules or materials. This approach is widely used in polymer science and materials engineering to design substances with specific properties.
The technique allows for precise control over the molecular architecture, enabling the creation of materials with tailored mechanical, thermal, or chemical characteristics. It is fundamental in the development of new composites, coatings, and other advanced materials.
ChemistryThe atmosphere, in the context of chemistry, refers to the layer of gases surrounding a planet or other celestial body, held in place by gravity. Earth's atmosphere is composed of nitrogen, oxygen, argon, carbon dioxide, and trace amounts of other gases, playing a critical role in sustaining life and influencing climate. It acts as a protective shield against harmful solar radiation and regulates temperature by trapping heat, a phenomenon known as the greenhouse effect. Understanding the chemical composition and dynamics of the atmosphere is essential for addressing environmental challenges such as air pollution and climate change.
Chemists study the atmosphere to monitor changes in its composition, especially the increase in greenhouse gases like carbon dioxide and methane, which are linked to global warming. Atmospheric chemistry also explores the formation and depletion of ozone in the stratosphere, which protects life on Earth from ultraviolet radiation. Research in this field contributes to the development of policies and technologies aimed at reducing emissions and mitigating the impacts of human activities on the planet's climate system.
ChemistryArsenic trioxide, with the chemical formula As2O3, is a potent and versatile compound used in various industrial and medical applications. It is a white, odorless, and tasteless crystalline solid that dissolves in water to form a weakly acidic solution. Historically, it has been used as a poison, but in modern times, it serves as a precursor to other arsenic compounds and in the treatment of acute promyelocytic leukemia (APL).
The compound's mechanism of action in cancer treatment involves the degradation of the PML-RARα fusion protein, leading to the differentiation of leukemic cells and their eventual apoptosis. Despite its toxicity, arsenic trioxide's therapeutic benefits in APL have been well-documented, showcasing the delicate balance between poison and medicine. Its use is strictly controlled due to the potential for severe side effects, including cardiac arrhythmias and liver damage.
ChemistryAngiotensin II is a potent vasoconstrictor peptide hormone that plays a crucial role in the regulation of blood pressure and fluid balance in the body. It is part of the renin-angiotensin system, which is targeted by various medications to treat hypertension and heart failure.
The hormone is produced through the enzymatic cleavage of angiotensin I by the angiotensin-converting enzyme (ACE), primarily in the lungs. Its actions include stimulating the release of aldosterone from the adrenal cortex, which increases sodium reabsorption in the kidneys, leading to increased blood volume and pressure.
ChemistryAdenine and Thymine are two of the four nucleobases used in forming nucleotides of the genetic material in DNA. Adenine pairs with Thymine in the DNA double helix, a fundamental aspect of the molecular structure of DNA. This pairing is crucial for the replication of DNA and the transmission of genetic information from one generation to the next.
The interaction between Adenine and Thymine is stabilized by two hydrogen bonds, which is a key factor in the specificity of base pairing in DNA. This specificity ensures the accurate replication of DNA during cell division, a process vital for the growth, development, and reproduction of all known living organisms. The study of these nucleobases and their interactions is a cornerstone of molecular biology and genetics.
ChemistryAlkaline Transition refers to the process by which a substance undergoes a change in its chemical properties when exposed to alkaline conditions. This transition can involve alterations in molecular structure, solubility, or reactivity, which are significant in various chemical reactions and industrial processes. Understanding these transitions is essential for chemists working in fields such as pharmaceuticals, environmental science, and materials engineering.
The study of Alkaline Transition provides insights into how substances behave under different pH levels, which is crucial for designing chemical processes and products. For example, in the pharmaceutical industry, controlling the alkaline transition of a drug can affect its stability and efficacy. Similarly, in environmental science, alkaline transitions can influence the degradation of pollutants, highlighting the importance of this concept in both theoretical and applied chemistry.
ChemistryAtomic percent, often abbreviated as at.%, is a measure of the composition of a mixture in terms of the number of atoms of a particular element relative to the total number of atoms in the mixture. It is a fundamental concept in chemistry and materials science, providing a precise way to describe the atomic makeup of alloys, compounds, and other mixtures. This measurement is crucial for understanding the properties and behaviors of materials at the atomic level, enabling scientists and engineers to tailor materials for specific applications.
In practical terms, atomic percent is used extensively in the field of metallurgy and semiconductor manufacturing, where the precise control of material composition is essential. For example, doping silicon with phosphorus to create n-type semiconductors requires exact atomic percent calculations to achieve the desired electrical properties. The concept also plays a vital role in the study of phase diagrams, where it helps in predicting the phases present in a material at equilibrium under specific conditions.
ChemistryLast updated: