Search

The inherent acidic nature of the stratum corneum (SC), the so-called "acid mantle", has a multitude of effects on skin barrier integrity owing to its (patho)physiological role in skin homeostasis, antimicrobial defense, and inflammation. Several salient SC acidifying mechanisms, including the breakdown of FLG (filaggrin) protein, lipid processing, and the activity of the sodium proton pump SLC9A1/NHE1, are indispensable for the structural and functional integrity and cohesion of the SC as they contribute immensely to the origin, generation, maintenance, and overall SC acidification of the skin surface pH (pHss). As many endogenous and exogenous factors can affect the pHss, the pHss can inevitably deviate from its optimum. The elevation of the pHss is often accompanied by abnormalities in SC lipid metabolism and organization, SC cohesion, and SC integrity and is commonly observed in eczema, which is associated with symptoms of dry skin, inflammation, pruritus, and infection. In psoriasis, it seems that the pHss is altered as well; however, in this case, it is likely to be lower than the physiological pHss. Due to the negative effects of an altered pHss in both eczema and psoriasis, it has been suggested to maintain the pHss at physiological levels by utilizing pH-balanced topical cleansers and moisturizers that can improve the skin's structural and functional integrity by benefiting skin moisturization and the regeneration and organization of the SC barrier. The principal aim of this review is to gather an understanding of the existing research and to stimulate critical thinking and inspire innovative ideas about 'known unknowns', considering the origin, intricate nature, and prime role of the pHss in human skin health, as well as the pathogenesis of eczema and psoriasis. [ABSTRACT FROM AUTHOR]

The inherent acidic nature of the stratum corneum (SC), the so-called “acid mantle”, has a multitude of effects on skin barrier integrity owing to its (patho)physiological role in skin homeostasis, antimicrobial defense, and inflammation. Several salient SC acidifying mechanisms, including the breakdown of FLG (filaggrin) protein, lipid processing, and the activity of the sodium proton pump SLC9A1/NHE1, are indispensable for the structural and functional integrity and cohesion of the SC as they contribute immensely to the origin, generation, maintenance, and overall SC acidification of the skin surface pH (pHss). As many endogenous and exogenous factors can affect the pHss, the pHss can inevitably deviate from its optimum. The elevation of the pHss is often accompanied by abnormalities in SC lipid metabolism and organization, SC cohesion, and SC integrity and is commonly observed in eczema, which is associated with symptoms of dry skin, inflammation, pruritus, and infection. In psoriasis, it seems that the pHss is altered as well; however, in this case, it is likely to be lower than the physiological pHss. Due to the negative effects of an altered pHss in both eczema and psoriasis, it has been suggested to maintain the pHss at physiological levels by utilizing pH-balanced topical cleansers and moisturizers that can improve the skin’s structural and functional integrity by benefiting skin moisturization and the regeneration and organization of the SC barrier. The principal aim of this review is to gather an understanding of the existing research and to stimulate critical thinking and inspire innovative ideas about ‘known unknowns’, considering the origin, intricate nature, and prime role of the pHss in human skin health, as well as the pathogenesis of eczema and psoriasis.

Due to their cost-effectiveness, low toxicity, and naturally renewable properties, bio-coagulants for water treatment are gaining popularity. In this context, four bio-coagulants were tested for their ability in turbidity reduction in a synthetic bentonite suspension: Opuntia ficus indica (OFI) and Moringa oleifera (MO) seeds, two well-established vegetal materials in the domain of bio-coagulation, and Algerian Aloe vera (AV) and Pinus halepensis seeds (PHS), both of which have received very few or no study in turbidity reduction in water and wastewater. A comparative study was conducted with regard to two well-known inorganic coagulants, ferric chloride and Alum. Extraction salts, pH, coagulant dose, initial turbidity, and aging effects were examined. When compared to chemical coagulants, the four bio-coagulants worked very well, removing approximately 100% of the turbidity at natural pH of 7.5 using optimal doses of 1.5, 3, 3, 3.5, 1.5, and 1.5 mL/200 mL for AV, OFI, MO, PHS, Alum, and FeCl3, respectively, at a broad range of pH (2 to 8), and causing no pH alteration of the treated water. Polysaccharides and proteins involved in inter-particle bridging and charge neutralization may be the active coagulation-flocculation molecules. The four bio-coagulants produced less sludge amount than Alum and Ferric chloride. This research not only shows that MO and OFI are effective in eliminating turbidity, but it also highlights the great potential of Algerian AV and PHS seeds as promising bio-coagulants in the treatment of polluted water. [ABSTRACT FROM AUTHOR]

Impressed current cathodic protection (ICCP) was widely applied for the corrosion control of reinforced concrete. During the ICCP treatment, the anodic reactions happened on the primary anode surface may induce acidification and subsequently pH drop in the vicinity of the anode, leading to damage of the external anode mortar. In this study, the relationship between the applied current (simulating ICCP treatment) on the Ti mesh anode and pH alterations in simulated concrete pore (SCP) solution (with/without chlorides) was investigated. It was found that the applied current slightly reduced the corrosion resistance of Ti mesh; this negative effect was more pronounced in the presence of chlorides. The pH value of SCP solution near Ti mesh anode decreased when the external current was applied. The consumption rate of OH– ion was higher in the chloride-containing SCP solution. A mathematical model was proposed between the electric charge quantity (Q) and OH– concentration (cOH–) in SCP solution near Ti mesh anode. This model is a useful tool to quantitatively identify the acidification damage induced by impressed current from the perspective of pH alternation near Ti mesh anode.

The use of DNA triplex association is advantageous for the reconfiguration of dynamic DNA nanostructures through pH alteration and can provide environmental control for both structural changes and molecular signaling. The combination of pH-induced triplex-forming oligonucleotide (TFOs) binding with toehold-mediated strand displacement has recently garnered significant attention in the field of structural DNA nanotechnology. While most previous studies use single-stranded DNA to displace or replace TFOs within the triplex, here we demonstrate that pH alteration allows a DNA duplex, with a toehold assistance, to displace TFOs from the components of another DNA duplex. We examined the dependence of this process on toehold length and show that the pH changes allow for cyclic oscillations between two molecular formations. We implemented the duplex/triplex design onto the surface of 2D DNA origami in the form outlining binary digits 0 or 1 and verified the oscillatory conformational changes between the two formations with atomic force microscopy.

Background: Hattaraki pallye or prickly lettuce ( Lactuca scariola Linn.) is one among several green leafy plants that grow in north Karnataka; it is usually consumed by the people of this region and is found to be antidiabetic in nature. The objective of this study is to evaluate hypoglycemic activities of supplementation with aqueous extract of prickly lettuce ( L. scariola) leaves in vivo in acute and subchronic exposure with or without nickel (II) along with its glucose reduction capabilities with or without nickel (II) at pH 7.0 and 9.0 in vitro. Methods: Percentage glucose reduction (in vitro) was determined by glucose oxidase-peroxidase enzymatic method at pH 7.0 and pH 9.0 using UV-Vis spectrophotometer. Hypoglycemic activities of L. scariola were carried out in alloxan-induced male diabetic rats at both acute and subchronic exposure. Results: The results showed a significant alteration in the λmax value of Ni (II) in combination with L. scariola leaves extracts at both pH 7.0 and 9.0. The aqueous extract also produced a significant reduction in the glucose concentration at pH 7.0 and pH 9.0 even in presence of Ni (II) in vitro. Lactuca scariola leaves in either acute or subchronic supplementation showed a greater glucose tolerance and hypoglycemic regulation of blood sugar in diabetic rats with or without nickel (II) treatments. Conclusions: Lactuca scariola leaves can be a substitute for synthetic drugs to treat diabetic patients. [ABSTRACT FROM AUTHOR]

Transforming metal particle combustion may require alteration of the metal oxide passivation shell surrounding the metal core. One approach for aluminum (Al) relies on the hydrated form of the metal oxide to incite surface reactions. This study explores the conditions required for hydrating alumina (Al 2 O 3) particles and then extends those conditions toward hydration of the Al 2 O 3 passivation layer surrounding an Al core particle. By raising the pH of the water slurry to 11 and controlling temperature and time in slurry (i.e., aging), aluminum hydroxide Al(OH) 3 formation from Al 2 O 3 particles was optimized. The procedure was then extended to Al nanoparticles (nAl). Even though heating and extended aging time in slurry proved advantageous for Al 2 O 3 particles, these conditions were discarded for nAl particles because they favored formation of AlOOH, a less desirable hydrate. Through microscopy, spectroscopy, X-ray diffraction, and thermal analyses, results indicate that for a pH range of 11.26–11.56, the original Al 2 O 3 shell on Al particles transformed into Al(OH) 3. Results indicate a feasible path forward towards producing new shell chemistries that may result in more directed energy from metal particle combustion. [Display omitted] • Al 2 O 3 particles were optimally hydrated into Al(OH) 3 by controlling pH of a water-NaOH slurry. • A slurry pH 11.26–11.55 optimally hydrated Al particles by replacing the Al 2 O 3 shell with Al(OH) 3. • Formation of AlOOH is an indication of Al core consumption during hydration processing. • Aging in solution, heating, and pH are factors controlling surface hydration of Al particles. • Ca(OH) 2 can replace NaOH to reduce solution enthalpy for easier and safer hydration processing. [ABSTRACT FROM AUTHOR]

Abstract: Efforts for developing protein films as biodegradable packaging materials have increased in recent years. One of the drawbacks of such films is that their functional properties are generally inferior to those of synthetic films. Although protein films typically have excellent gas barrier properties, they tend to have higher water vapor permeability, are mechanically weaker, and have lower elongation as compared to most synthetic polymers. This paper will review the various methods that have been reported to enhance the physical and barrier properties of protein films. The effects of film formulation and preparation conditions, including plasticization, pH alteration, and lipid addition, on the functional properties of protein films are discussed. The paper also offers a comprehensive review of the various methods used to modify protein film functional properties, including cross-linking techniques induced by heat, chemical, enzymes, and irradiation, and use of nanocomposites to enhance their barrier properties. A critical comparison of the different technical solutions is offered, and the challenges and potential applications of these films are discussed. [Copyright &y& Elsevier]

In this study, highly uniform MCM-41 mesoporous silica was synthesised from rice husk ash-derived sodium silicate using cetyltrimethyl ammonium chloride (CTAC) as a template. The chemical composition of the gel mixture was based on a SiO2:CTAC:H2O molar ratio of 1:0.5:75. When the pH value was initially controlled at ranges of 5.0-10.5 for 5 h and then immediately adjusted to 11.25 for the next 1 h, the structural uniformity of MCM-41 was abruptly increased by 3.3-7.5 times of the single pH value at 11.25, respectively. Moreover, thermal and hydrothermal stabilities at 900 and 250°C were clearly observed. © 2012 Canadian Society for Chemical Engineering [ABSTRACT FROM AUTHOR]

The anthrax lethal factor (LF) is a Zn2+-endopeptidase specific for mitogen-activated protein kinase kinases (MAPKKs), which are cleaved within their N-terminal region. Much line of effort was carried out to elucidate the catalytic activity of LF for designing the inhibitor and to understand the cellular mechanism of its cytotoxicity. Current assay methods to analyze the LF activity have been based on a synthetic peptide, consisting of 15–20 residues around being cleaved. However, there are accumulating reports that the region distal to cleavage site is required for the LF-mediated proteolysis of substrate. In this study, we demonstrate the catalytic properties of LF, using the full-length native substrate, MEK. We described the catalytic properties of LF focused on the effects of the pH alteration, which was encountered during the endocytosis of lethal toxin, and of the requirement for metal ions. We present the first evidence that additional metal ions are required for the LF catalyzed hydrolysis of native substrate, and that the pH alteration causes a significant change of catalytic properties of LF. [Copyright &y& Elsevier]

Impressed current cathodic protection (ICCP) was widely applied for the corrosion control of reinforced concrete. During the ICCP treatment, the anodic reactions happened on the primary anode surface may induce acidification and subsequently pH drop in the vicinity of the anode, leading to damage of the external anode mortar. In this study, the relationship between the applied current (simulating ICCP treatment) on the Ti mesh anode and pH alterations in simulated concrete pore (SCP) solution (with/without chlorides) was investigated. It was found that the applied current slightly reduced the corrosion resistance of Ti mesh; this negative effect was more pronounced in the presence of chlorides. The pH value of SCP solution near Ti mesh anode decreased when the external current was applied. The consumption rate of OH - ion was higher in the chloride-containing SCP solution. A mathematical model was proposed between the electric charge quantity (Q) and OH - concentration (cOH - ) in SCP solution near Ti mesh anode. This model is a useful tool to quantitatively identify the acidification damage induced by impressed current from the perspective of pH alternation near Ti mesh anode.