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Topic Review
Steroidogenesis, Oxidative Stress and Male Hypogonadism
Steroid sex hormones are classified as androgens, estrogens, and progestogens. Although all three classes are important in male and female physiology, androgens are associated with "musculisation" effects and are considered primarily male sex hormones. Androgens have diverse functions in muscle physiology, lean body mass, the regulation of adipose tissue, bone density, neurocognitive regulation, and spermatogenesis, male reproductive and sexual function.
  • 955
  • 29 Mar 2022
Topic Review
Sterically Hindered Quaternary Phosphonium Salts (QPSs)
Structure–activity relationships are important for the design of biocides and sanitizers. The most commonly used biocides are nitrogen-containing compounds; the phosphorus-containing ones have been studied to a lesser extent. In the present study, a broad range of sterically hindered quaternary phosphonium salts (QPSs) based on tri-tert-butylphosphine was tested for their activity against Gram-positive (Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria and fungi (Candida albicans, Trichophyton mentagrophytes var. gypseum). Additionally, the hemolytic and cytotoxic properties of QPSs were determined using blood and a normal liver cell line, respectively.
  • 387
  • 23 Jan 2022
Topic Review
Stereotype Embodiment Theory
Stereotype embodiment theory (SET) is a theoretical model first posited by psychologist Becca Levy to explain the process by which age stereotypes influence the health of older adults. There are multiple well-documented effects of age stereotypes on a number of cognitive and physical outcomes (including memory, cardiovascular reactivity, and longevity). SET explains these findings according to a three-step process: Underlying these three steps are SET's four main theoretical premises. According to Levy (2009): "The theory has four components: The stereotypes (a) become internalized across the lifespan, (b) can operate unconsciously, (c) gain salience from self-relevance, and (d) utilize multiple pathways." Although this theory was developed to explain the operation of age stereotypes across the lifespan, it may also explain how other types of self-stereotypes operate, such as race stereotypes among African Americans and gender stereotypes among women.
  • 1.8K
  • 02 Nov 2022
Biography
Stephen L. Adler
Stephen Louis Adler (born November 30, 1939) is an American physicist specializing in elementary particles and field theory. Adler was born in New York City . He received an A.B. degree at Harvard University in 1961, where he was a Putnam Fellow, and a Ph.D. from Princeton University in 1964. He is the son of Irving Adler and Ruth Adler and older brother of Peggy Adler. Adler was elected a F
  • 453
  • 29 Dec 2022
Biography
Stephen Hawking
Stephen William Hawking CH CBE FRS FRSA (8 January 1942 – 14 March 2018) was an English theoretical physicist, cosmologist, and author who was director of research at the Centre for Theoretical Cosmology at the University of Cambridge at the time of his death.[1][2][3] He was the Lucasian Professor of Mathematics at the University of Cambridge between 1979 and 2009. Hawking was born in Oxford
  • 3.4K
  • 30 Nov 2022
Biography
Stephen Emmott
Stephen Emmott (born 3 June 1960) is a British scientist, entrepreneur and chief scientist of Scientific.[1][2] Emmott was named one of London's most influential scientists, and one of the most influential people in London by the Evening Standard in 2012.[3] Emmott studied at the University of York, where he completed a B.Sc. in Biological Sciences (experimental psychology), graduating in 198
  • 1.3K
  • 30 Dec 2022
Topic Review
Stemness and Apoptosis
Stemness and apoptosis may highlight the dichotomy between regeneration and demise in the complex pathway proceeding from ontogenesis to the end of life. In the last few years, the concept has emerged that the same microRNAs (miRNAs) can be concurrently implicated in both apoptosis-related mechanisms and cell differentiation. Whether the differentiation process gives rise to the architecture of brain areas, any long-lasting perturbation of miRNA expression can be related to the occurrence of neurodevelopmental/neuropathological conditions. Moreover, as a consequence of neural stem cell (NSC) transformation to cancer stem cells (CSCs), the fine modulation of distinct miRNAs becomes necessary. This event implies controlling the expression of pro/anti-apoptotic target genes, which is crucial for the management of neural/neural crest-derived CSCs in brain tumors, neuroblastoma, and melanoma.
  • 656
  • 20 Apr 2023
Topic Review
Stem/Leaf Anatomy of Aragoa (Plantaginaceae)
Aragoa is a shrubby genus endemic to páramo in the northern Andes representing the sister group to Plantago and Limosella. Stem and leaf structure of Aragoa corrugatifolia were studied to clarify the evolutionary pathways and ecological significance of their anatomical traits. Aragoa and Plantago share a non-fascicular primary vascular system, rayless wood and secondary phloem, and anomocytic stomata. Aragoa is distinctive from most Plantaginaceae in the presence of cortical aerenchyma and of helical thickenings in vessels. Its procambium emerges in the primary meristem ring as a continuous cylinder. The view on the ring meristem and procambial strands as developmental stages in the formation of a primary vascular system is not relevant for Aragoa, and probably for other Plantaginaceae. The raylessness is synapomorphic for the crown clade of Plantaginaceae comprising Aragoa, Littorella, Plantago, Veronica, Picrorhiza, Wulfenia, and Veronicastrum. The loss of rays is thought to be predetermined by procambium rather than by the vascular cambium. The extremely narrow vessels with helical thickenings are presumably adaptive to hydric and thermic conditions of páramo. Cortical aerenchyma is thought to be a response to the local hypoxia caused by the water retained by ericoid leaves. Trichomes on juvenile leaves are expected to be the traits of considerable taxonomic importance. 
  • 553
  • 04 Sep 2021
Topic Review
Stem-Cell-Based Therapy in Alzheimer’s Disease
Stem cells are a versatile source for cell therapy. Their use is particularly significant for the treatment of neurological disorders for which no definitive conventional medical treatment is available. Neurological disorders are of diverse etiology and pathogenesis. Alzheimer’s disease (AD) is caused by abnormal protein deposits, leading to progressive dementia.
  • 485
  • 15 Nov 2022
Topic Review
Stem Cells-Derived Extracellular Vesicles
Endosome-derived small extracellular vesicles (EVs), often referred to as exosomes, are produced by almost all, if not all, cell types, and are critical for intercellular communication. They are composed of a lipid bilayer associated with membrane proteins and contain a payload of lipids, proteins and regulatory RNAs that depends on the parental cell physiological condition. By transferring their “cargo”, exosomes can modulate the phenotype of neighboring and distant cells. Stem cells (SC) were widely studied for therapeutic applications regarding their regenerative/reparative potential as well as their immunomodulatory properties. Whether from autologous or allogeneic source, SC beneficial effects in terms of repair and regeneration are largely attributed to their paracrine signaling notably through secreted EVs. Subsequently, SC-derived EVs have been investigated for the treatment of various diseases, including inflammatory skin disorders, and are today fast-track cell-free tools for regenerative/reparative strategies. 
  • 577
  • 22 Sep 2021
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