China
Africa
Explore chapters and articles related to this topic
Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Revati Phalkey, Naima Bradley, Alec Dobney, Virginia Murray, John O’Hagan, Mutahir Ahmad, Darren Addison, Tracy Gooding, Timothy W Gant, Emma L Marczylo, Caryn L Cox
When radon is inhaled, its 3.82 day half-life means that there is a small probability of the atoms decaying whilst in the lungs, and most are simply exhaled. The decay products, however, not only have much shorter half-lives, but their chemically active nature means that they are more readily caught by the mucous membranes that line the airways; those attached to aerosols tend to deposit in the bronchi, the unattached tend to be deposited more deeply in the lung. Once on the mucous membranes, the isotopes of polonium, bismuth and lead decay radioactively before the body’s clearance mechanisms can remove them (to the mouth, nose or GI tract). The range of alpha particles in tissue is particularly important, as it corresponds to the distance from the surface of the mucous membrane to the basal cells that line the airways. Radiation damage to the DNA in the cell nucleus risks mutations that can lead to cancer.
Genes and genomics
Published in Firdos Alam Khan, Biotechnology Fundamentals, 2018
Eukaryotic cells are about 10 times the size of a typical prokaryote and can be as much as 1000 times greater in volume. The major difference between prokaryotes and eukaryotes is that eukaryotic cells contain membrane-bound compartments in which specific metabolic activities take place. Most important among these is the presence of a cell nucleus, a membrane-delineated compartment that houses the eukaryotic cell’s DNA. It is this nucleus that gives the eukaryote its name, which means “true nucleus.” The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup. The eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with histone proteins. All chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane. Some eukaryotic organelles such as mitochondria also contain some DNA. Eukaryotes can move using cilia or flagella. The flagella of a eukaryote are more complex than those of prokaryotes.
Naturally Occurring Polymers—Animals
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
While DNA is the depository of our genetic information, it is “held captive” or “protected” by the nuclear envelope, remaining within this envelope. Yet, the information held by the double-stranded DNA is transferred throughout the cell with results felt throughout the body. Briefly, polymerase transcribes the information on the DNA into single-stranded mRNA. The mRNA single strands move from the cell nucleus into the cell cytoplasm through openings in the nuclear envelope called nuclear pore complexes.
Antibacterial agents applied as antivirals in textile-based PPE: a narrative review
Published in The Journal of The Textile Institute, 2022
Zulfiqar Ali Raza, Muhammad Taqi, Muhammad Rizwan Tariq
A viral infection usually results due to complex interactions at the interface of the virus and the host matrix. Initially, an invader virus reaches there, attaches to the receptor of the host cell, then transfers its viral genome into the cell cytoplasm, which then penetrates the host cell nucleus, where the viral mRNA directs protein synthesis in a systematic pattern. Then, the replication of the viral genome and the synthesis of structural proteins (capsid) occurs to assemble the novel virions which are then released from the infected host human cell; thus a chain of infection starts in the human body (Thi Ngoc Dung et al., 2020). In the clinical trials, both directly and indirectly-acting antiviral agents have been employed; the former inhibits the viral cycle at any of the above-mentioned phases to target the viral proteins and the latter targets the host cell factors which usually support the viral attachment to host. The host targeting antivirals (like silver, copper, polyphenols, etc.) employed in drug formulations express broad-spectrum antiviral activity (Iyigundogdu et al., 2017).
Computer-assisted grading of follicular lymphoma: a classification based on SVM, machine learning, and transfer learning approaches
Published in The Imaging Science Journal, 2022
To forecast the grading of the follicular tissue sample, morphological features of the cell nucleus and cytoplasm were classified using SVM. Based on SVM kernel types, classification accuracy is determined. SVMs can produce an ideal hyperplane that maximizes the margin, where the margin is the greatest distance. SVM is preferred over LDA and logical regression because it produces more encouraging findings. In SVM classification, linear and Gaussian Kernel is used to classify FL histology as cancerous and non-cancerous. If the sample is cancerous, then discriminate among grade 1, grade 2, and grade 3. The Gaussian kernel function for multiclass classification in SVM was expressed as; In this formula, stands for the feature vector, for the Euclidean distance between two feature vectors, for a hyper-parameter that modifies the kernel function's smoothness, and for a free parameter. The FL histology is classified using the kernel described in equation 5. First, multiclass classification of grade 1, grade 2, and grade 3 tissue samples is performed, followed by binary classification between grade 1 and grade 2 and between grade 2 and grade 3 tissue samples separately. Section 4.1 contains the results of SVM classifiers.
Structure, nitric oxide (NO) generation and antitumor activity of binuclear tetranitrosyl iron complex with 4-aminothiophenolyl as nitrosyl ferredoxins mimic
Published in Journal of Coordination Chemistry, 2021
N.A. Sanina, G.I. Kozub, T.A. Kondrat’eva, T.S. Stupina, A.A. Balakina, A.A. Terent’ev, I.V. Sulimenkov, N.S. Ovanesyan, P.V. Dorovatovskii, V.N. Khrustalev, S.M. Aldoshin
NF-κB nuclear factor is a transcription factor regulating genes involved in control of proliferation and cell death in response to various external stimuli ranging from infectious agents and oxidative stress to chemotherapeutic medicines [50]. A functional protein consists of two sub-units that can be represented by polypeptides p50, p5, and p65. Polypeptide p65 has a transactivation domain, and p50/p65 dimer is the most common form of NF-κB. NF-κB protein in its inactive form is located in cytoplasm, while upon activation is transported to the cell nucleus as a response to external stimuli [51]. After that, NF-κB transcription factor binds regulatory sites of target genes, which leads to their activation or repression [52].