What are the primary physical, chemical, and biological factors that contribute to membrane fouling in water treatment?4 answersMembrane fouling in water treatment is influenced by various physical, chemical, and biological factors. Physical factors include the type and size of foulants, as well as the surface roughness of the membrane. Chemical factors involve the interaction between foulants and the membrane surface, which is influenced by the surface chemistry of the membrane. Biological factors play a significant role in membrane fouling, particularly biofouling, which is the attachment and growth of microorganisms on the membrane surface. The presence of organic macromolecules and microorganisms can lead to the formation of a fouling layer, reducing membrane performance. Additionally, the release of extracellular polymeric substances (EPS) by microorganisms can contribute to fouling. Understanding these factors is crucial for developing effective strategies to mitigate membrane fouling and improve water treatment processes.
How does humidity affect the structure and function of cell membranes?5 answersHumidity has a significant impact on the structure and function of cell membranes. The hydration level affects the microstructure of anion exchange membranes (AEMs) and their conductivity and stability. During the operation of proton-exchange membrane fuel cells, hydration/dehydration cycles occur due to changes in temperature and relative humidity, which can affect the membrane-electrode assemblies. In glass-supported DPPC bilayers, structural changes are observed in response to relative humidity variations. In the case of proton exchange membranes (PEMs), low relative humidity can lead to reduced conductivity, limiting their efficiency in fuel cells. In the context of membrane electrode assemblies (MEAs), humidity affects the degradation mechanisms of catalyst layers and proton exchange membranes, with higher water content accelerating Pt coarsening and carbon corrosion, while low humidity enhances ionomer degradation and Pt dissolution.
How does membrane dynamics affects cancer?5 answersMembrane dynamics play a crucial role in cancer. The softness of cancer cells compared to normal cells allows for the efficient delivery of therapeutic agents into cancer cells while minimizing the impact on normal cells. The sensitivity of epithelial cancer cells to different modes of cytotoxicity by natural killer (NK) cells is regulated by plasma membrane dynamics, such as blebs and lamellipodia formation. Reduction in cholesterol concentration in cancer cell membranes contributes to their softening, making them more susceptible to mechanical deformation. The interaction between βPix and Dynamin 2 promotes lamellipodia formation and membrane dynamics, facilitating cancer cell invasion. Dysregulation of plasma membrane domains can promote oncogenic signaling, while membrane-targeted dietary bioactives have the ability to remodel these domains and reduce cancer risk.
How is membrane plasicity altered in heart failure.?4 answersMembrane plasticity is altered in heart failure. Ion channel biophysical changes occur during heart failure, leading to increased arrhythmic risk. Abnormal calcium movements may contribute to the depression of myocardial contractility seen in heart failure, and these alterations may be produced by abnormalities in both the channel proteins and the membrane lipids. In patients with chronic heart failure, alveolar-capillary membrane dysfunction may contribute to symptom exacerbation and exercise intolerance. The decrease in the pulmonary diffusing capacity for carbon monoxide (DLCO) in heart failure is due to a restrictive ventilatory pattern, and the decrease in the membrane conductance is compensated by the increase in pulmonary capillary blood volume (Vc). In heart failure, changes in the expression and function of ion channels, such as potassium channels and the Na/Ca exchange, have been described, as well as alterations in the expression and phosphorylation status of proteins involved in calcium handling, such as the ryanodine receptor and the sarcoplasmic reticulum Ca-ATPase (SERCA).
What are the components of the cell membrane?5 answersThe cell membrane is composed of proteins and lipids. The proteins and lipids in the cell membrane play crucial roles in defining the boundaries of the cell, maintaining the differences between the intracellular and extracellular environments, and facilitating communication between cells and their environment. The lipids form a phospholipid bilayer, with hydrophilic heads facing the aqueous environments and hydrophobic tails facing each other. The proteins in the cell membrane can be classified into two types: integral proteins, which span the bilayer, and peripheral proteins, which lie outside the core of the bilayer. These proteins perform a variety of functions, including selective permeation, signal transduction, and protection against pathogens. Overall, the components of the cell membrane work together to maintain the integrity and functionality of the cell.
What is the effect of the primary antibody binding on the membrane?3 answersThe effect of primary antibody binding on the membrane is dependent on the specific antibody and its epitope. Antibodies can elicit various mechanisms to delete target cells, including complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity, and antibody-dependent cellular phagocytosis. The binding of antibodies can restrict the range of orientations of the globular domain with respect to the membrane and decrease the distance between the tail and membrane. Additionally, the binding of antibodies can modulate the interactions between the flexible tail and globular domain differently. Antibody binding can also lead to changes in the expression of membrane antigens, with the quantity of immunoglobulin-like receptors for the antigen being reduced. The effect of antibody binding on lymphocyte membrane structures can be influenced by factors outside the cell, such as the presence or absence of T cell influences.