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Polysaccharides from Marine Micro- and Macro-Organisms
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Kannan Kamala, Pitchiah Sivaperumal, Gopal Dharani
It is composed of the repeating units of disaccharides including D-glucuronic acid and N-acetyl D glucosamine without protein bounds (Lindahl et al., 2015). It is a multifunctional glue, having a smooth viscous property used in various medicinal fields in humans. In particular it is used in joint disease, ophthalmological surgical aid, and wound healing (Goa and Benfield, 1994; Lee et al., 2003). It is semi-flexible in nature with high molecular weight, which decreases the unique viscoelastic property of the solution in the ophthalmological field (Lapcik et al., 1998). As well, it has an enormous beneficial claims in rheumatology, tissue engineering, pulmonary pathology, and orthopedic surgery (Giji and Arumugam, 2014). In addition, it has a crucial role in the transport of macromolecules from cell to bacteria and tissue penetration and hydration by the absorbing capacity of water molecules (Garg and Hales, 2004). The scaffold preparation of hyaluronic acid with chitosan has been employed in chronic ulcer cure and wound dressing (Abdel-Mohsen et al., 2017; Abdelrahman et al., 2020).
The science of ageing
Published in Michael Parker, Charlie James, Fundamentals for Cosmetic Practice, 2022
The amount of sebum production and water storage within the skin falls as we get older, resulting in chronically drier skin. Water retention within the skin is impaired by two key mechanisms, the first of which is an altered amino acid composition, decreasing the osmotic pressure within the epidermis and thus attracting and retaining fewer water molecules. The second change is increased permeability of the skin itself, simply making the skin leakier. As older skin has less sebum and water retention with increased water loss, the compound effect is that of dehydrated tissues. Dehydrated skin has a flakier appearance with increased shedding of keratinocytes, as well as having an increased susceptibility to inflammatory conditions and opportunistic skin infections.
Body fluids and electrolytes
Published in Peate Ian, Dutton Helen, Acute Nursing Care, 2020
Loss of body fluids increases the osmolality of the blood. This causes water molecules to shift out of the intracellular space into the more concentrated intravascular compartment. If this is balanced by increasing the water intake and reducing urine output, the body’s fluid volume can be restored. However, if there is an inadequate supply of water, or if the kidneys are unable to retain water, the fluid from the cells continues to shift to the intravascular space, causing cell shrinkage and reduced cellular function.
Carbonic anhydrase inhibitory activity of phthalimide-capped benzene sulphonamide derivatives
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Deepak Shilkar, Mohd Usman Mohd Siddique, Silvia Bua, Sabina Yasmin, Mrunali Patil, Ajay Kumar Timiri, Claudiu T. Supuran, Venkatesan Jayaprakash
All CA families catalyse the reversible hydration of carbon dioxide. The active site of α-CAs consists of a zinc ion coordinated to three histidine residues and a water molecule. The water molecule acts as a nucleophile and attacks the carbon dioxide molecule, forming bicarbonate and a proton. The proton is then released into the solvent through a network of hydrogen bonds involving other amino acid residues such as glutamate and asparagine. The active site of carbonic anhydrase is highly conserved among different isoforms and species, indicating its functional importance7. Human carbonic anhydrase II (hCA II), one of the most extensively investigated isoforms, possesses an active site comprising a zinc ion (Zn2+) coordinated to three histidine residues (His94, His96, and His119) and a water molecule or hydroxide ion8. In coordination with these residues, the zinc ion coordinated water/hydroxide serves as a nucleophilic catalyst for enzymatic activity. Apart from zinc-binding histidines, residues in proximity to the active site are involved in substrate/inhibitor orientation. Glu106 establishes a hydrogen-bond network with Thr199 that is crucial for catalysis9–11. Additionally, a hydrophobic pocket encompassing Val121, Leu198, and Val143 influences substrate binding and modulates enzyme function10.
Data-driven approach to mitigate quality impact of hygroscopic pharmaceutical raw materials throughout the supply chain
Published in Pharmaceutical Development and Technology, 2022
Mary K. Chaves, Ron C. Kelly, Jacqueline E. Milne, Susan E. Burke
The majority of the free amino acids evaluated, other than arginine and proline, are not hygroscopic and do not show any significant weight loss by TGA (Table 5). The non-hygroscopic nature of these free amino acids is aligned with the work of Mellon and Hoover who also show these amino acids to be non-hygroscopic (Mellon and Hoover 1951). They suggested that the polar groups of these molecules must be coordinated in the crystal lattice in a way that makes them unavailable to interact with water molecules. Two of the hydrochloride salt forms, L-cysteine dihydrochloride and L-lysine hydrochloride, were confirmed to undergo a crystal form change by XRPD (Figures 2 and 3). These materials were classified as hygroscopic, regardless of the crystal form change, to ensure that the materials are protected from moisture to avoid this form conversion. L-cysteine hydrochloride monohydrate and l-cysteine dihydrochloride appear similar post-DVS by XRPD indicating that there may be some displacement of hydrochloride occurring during the DVS of L-cysteine dihydrochloride.
Advancing of titanium medical implants by surface engineering: recent progress and challenges
Published in Expert Opinion on Drug Delivery, 2021
The wettability represents a fundamental property of any material and it is related to the interfacial energies acting between the solid-liquid, solid-vapor and liquid–vapor interfaces that reveals information about the chemical structure of the material and its surface topography. These properties which can be hydrophilic (high wettability) and hydrophobic (low wettability) are results of the molecular interaction between the water molecules and molecules or atoms froms a solid surface and depends of other factors such as the surface tension, the surface energy (are also determined by the surface wettability) and the surface morphology [42]. Solid surfaces such as metals (Ti), glass and ceramics which are hydrophilic, have a higher surface energy (hard solids) and water can achieve complete wetting on these solids.