-
Molecules (Basel, Switzerland) Jan 2019The catalytic deoxygenation of bio-based feedstocks to fuels and chemicals presents new challenges to the catalytic scientist, with many transformations either performed... (Review)
Review
The catalytic deoxygenation of bio-based feedstocks to fuels and chemicals presents new challenges to the catalytic scientist, with many transformations either performed in or liberating water as a byproduct during reaction. The design of catalysts with tunable hydrophobicity to aid product and reactant adsorption or desorption, respectively, is vital for processes including (trans)esterification and condensation reactions employed in sustainable biodiesel production and bio-oil upgrading processes. Increasing surface hydrophobicity of catalyst materials offers a means to displace water from the catalyst active site, and minimizes potential deactivation or hydrolysis side reactions. Hybrid organic⁻inorganic porous solids offer exciting opportunities to tune surface polarity and hydrophobicity, as well as critical parameters in controlling adsorption, reactant activation, and product selectivity in liquid and vapor phase catalysis. Here, we review advances in the synthesis and application of sulfonic-acid-functionalized periodic mesoporous organosilicas (PMO) as tunable hydrophobic solid acid catalysts in reactions relevant to biorefining and biofuel production.
Topics: Acids; Biofuels; Biomass; Catalysis; Hydrolysis; Hydrophobic and Hydrophilic Interactions; Organically Modified Ceramics; Porosity
PubMed: 30634651
DOI: 10.3390/molecules24020239 -
European Review For Medical and... Mar 2023Diabetes is a chronic disease that can cause various complications and has a high prevalence. Evidence increasingly shows that acid-base homeostasis is critical to...
OBJECTIVE
Diabetes is a chronic disease that can cause various complications and has a high prevalence. Evidence increasingly shows that acid-base homeostasis is critical to maintaining normal metabolic function. This case-control study aims to evaluate the relationship between dietary acid load and the risk of type 2 diabetes.
PATIENTS AND METHODS
This study recruited 204 participants, 92 of whom had just been diagnosed with type 2 diabetes, and 102 healthy controls who were matched in age and gender as controls. Twenty-four dietary recall was used for dietary intake assessments. Dietary acid load was approximated using two different methods: potential renal acid load (PRAL) and net endogenous acid production (NEAP), both calculated from dietary recalls.
RESULTS
In the case and control groups, the dietary acid load mean scores were 4.18±26.8, 20.84±29.54 mEq/day for PRAL, and 55.11±29.23, 68.43±32.23 mEq/day for NEAP, respectively. When it came to the multiple possible confounders, the participants in the highest tertile of PRAL (OR 4.43, 95% CI: 1.38-23.81, ptrend<0.001) and NEAP (OR: 3.15, 95% CI: 1.53-9.59, ptrend<0.001) had a significantly higher risk of developing type 2 diabetes compared to those in the lowest tertile.
CONCLUSIONS
The findings of the present study suggest that a high acid load in the diet may increase the risk of type 2 diabetes. Therefore, it is possible that limiting dietary acid load could lower type 2 diabetes risk in vulnerable individuals.
Topics: Humans; Diabetes Mellitus, Type 2; Case-Control Studies; Diet; Kidney; Acids
PubMed: 37013762
DOI: 10.26355/eurrev_202303_31778 -
Reproductive Biology and Endocrinology... Jun 2024The epidemiologic evidence on the association between acid load potential of diet and the risk of diminished ovarian reserve (DOR) is scarce. We aim to explore the...
BACKGROUND
The epidemiologic evidence on the association between acid load potential of diet and the risk of diminished ovarian reserve (DOR) is scarce. We aim to explore the possible relationship between dietary acid load (DAL), markers of ovarian reserve and DOR risk in a case-control study.
METHODS
370 women (120 women with DOR and 250 women with normal ovarian reserve as controls), matched by age and BMI, were recruited. Dietary intake was obtained using a validated 80-item semi-quantitative food frequency questionnaire (FFQ). The DAL scores including the potential renal acid load (PRAL) and net endogenous acid production (NEAP) were calculated based on nutrients intake. NEAP and PRAL scores were categorized by quartiles based on the distribution of controls. Antral follicle count (AFC), serum antimullerian hormone (AMH) and anthropometric indices were measured. Logistic regression models were used to estimate multivariable odds ratio (OR) of DOR across quartiles of NEAP and PRAL scores.
RESULTS
Following increase in PRAL and NEAP scores, serum AMH significantly decreased in women with DOR. Also, AFC count had a significant decrease following increase in PRAL score (P = 0.045). After adjustment for multiple confounding variables, participants in the top quartile of PRAL had increased OR for DOR (OR: 1.26; 95%CI: 1.08-1.42, P = 0.254).
CONCLUSION
Diets with high acid-forming potential may negatively affect ovarian reserve in women with DOR. Also, high DAL may increase the risk of DOR. The association between DAL and markers of ovarian reserve should be explored in prospective studies and clinical trials.
Topics: Humans; Female; Case-Control Studies; Ovarian Reserve; Adult; Diet; Acids; Anti-Mullerian Hormone; Risk Factors; Ovarian Follicle; Young Adult
PubMed: 38835018
DOI: 10.1186/s12958-024-01238-2 -
Marine Drugs Oct 2022In search of alternative and sustainable sources of collagenous materials for biomedical applications, the scales of five Mediterranean fish species-fished in high...
Valorization of Fish Waste: Isolation and Characterization of Acid- and Pepsin-Soluble Collagen from the Scales of Mediterranean Fish and Fabrication of Collagen-Based Nanofibrous Scaffolds.
In search of alternative and sustainable sources of collagenous materials for biomedical applications, the scales of five Mediterranean fish species-fished in high tonnage in the Mediterranean region since they represent popular choices for the local diet-as well as those of the Atlantic salmon for comparison purposes, were comparatively studied for their acid- and pepsin-soluble collagen content. Fish scales that currently represent a discarded biomass of no value could be efficiently exploited for the production of a high added-value biomaterial. The isolated collagenous materials, which showed the typical electrophoretic patterns of type I collagen, were morphologically and physicochemically characterized. Using scanning electron microscopy the fibrous morphology of the isolated collagens was confirmed, while the hydroxyproline content, in conjunction with infrared spectroscopy and X-ray diffraction studies verified the characteristic for collagen amino acid profile and its secondary structure. The acid- and pepsin-soluble collagens isolated from the fish scales were blended with the bioactive sulfated marine polysaccharide ulvan and polyethylene oxide and electrospun to afford nanofibrous scaffolds that could find applications in the biomedical sector.
Topics: Animals; Pepsin A; Nanofibers; Collagen; Collagen Type I; Acids
PubMed: 36354987
DOI: 10.3390/md20110664 -
Environmental Science and Pollution... May 2022Genetically, modern broilers are fast-growing birds which attain the market age at the age of 5 weeks. To maintain optimum production, antibiotics have been commonly... (Review)
Review
Genetically, modern broilers are fast-growing birds which attain the market age at the age of 5 weeks. To maintain optimum production, antibiotics have been commonly included in the diets as growth promoters. However, due to the increase in antimicrobial resistance, their uses have been banned worldwide. To keep the optimum level of production and health in broiler industry, the use of alternative growth promoters such as probiotics, prebiotics, enzymes, and organic acids has been proposed. Chemically, organic acids are weak acids and only partially dissociate. They are considered safe and have been used for preservation of food for centuries. Nowadays, organic acids have been reported for antibacterial, immune potentiating, and growth promoters in broilers. In this review, the effects of dietary inclusion of organic acids on growth, nutrient digestibility, intestinal integrity, immune system, and antibacterial activity in broilers are discussed.
Topics: Acids; Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Anti-Bacterial Agents; Chickens; Diet; Dietary Supplements; Digestion; Organic Chemicals
PubMed: 35195862
DOI: 10.1007/s11356-022-19241-8 -
PloS One 2020Saponins are secondary metabolites from plants added to shampoos and beverages to make them foam, and the sapogenins released from them upon acid hydrolysis are commonly...
BACKGROUND
Saponins are secondary metabolites from plants added to shampoos and beverages to make them foam, and the sapogenins released from them upon acid hydrolysis are commonly used as starting materials for steroidal drugs. However, current methods embed the saponin in a thick "gum" material consisting of multiple impurities. This gum limits access to the saponin, reducing the efficiency of hydrolysis and requiring large amounts of heat, organic solvents and effort to recover the sapogenin. For centuries, herbalists have been making tinctures by soaking plant materials at room temperature, in mixtures of alcohol and water. Many herbal tinctures contain saponins floating freely in solution, gum free. The saponin from sarsaparilla (Smilax spp), sarsasaponin, yields the sapogenin, sarsasapogenin, upon acid hydrolysis. The retail price of sarsasapogenin is very high but would be lower if the "gum problem" could be avoided.
MATERIALS AND METHODS
We incubated sarsaparilla tincture under different conditions of temperature, acidity and duration then used quantitative nuclear magnetic resonance (qNMR) to measure the amount of sarsasapogenin produced by hydrolysis as well as the amount of its epimer, smilagenin.
RESULTS AND DISCUSSION
Most, if not all the sarsasaponin in sarsaparilla root powder is extracted into a solution of 45% ethanol (55% water) at room temperature and stays suspended without formation of any particles (gum). Acid hydrolysis of the saponin in this solution is very efficient, approaching 100%. The sarsasapogenin released by hydrolysis and the smilagenin produced by its epimerisation, migrate into the chloroform phase.
CONCLUSION
Sarsaparilla saponin diffuses into and disperses in a solution of alcohol:water (45:55) at room temperature. Hydrolysis of saponins in tincture provides a simple, inexpensive and environmentally friendly alternative.
Topics: Acids; Hydrolysis; Plant Roots; Sapogenins; Saponins; Secondary Metabolism; Smilax
PubMed: 33382809
DOI: 10.1371/journal.pone.0244654 -
MSphere Jan 2020Propionic, sorbic, and benzoic acids are organic weak acids that are widely used as food preservatives, where they play a critical role in preventing microbial growth....
Propionic, sorbic, and benzoic acids are organic weak acids that are widely used as food preservatives, where they play a critical role in preventing microbial growth. In this study, we uncovered new mechanisms of weak-acid resistance in molds. By screening a library of 401 transcription factor deletion strains in for sorbic acid hypersensitivity, a previously uncharacterized transcription factor was identified and named weak acid resistance A (WarA). The orthologous gene in the spoilage mold was identified and deleted. WarA was required for resistance to a range of weak acids, including sorbic, propionic, and benzoic acids. A transcriptomic analysis was performed to characterize genes regulated by WarA during sorbic acid treatment in Several genes were significantly upregulated in the wild type compared with a Δ mutant, including genes encoding putative weak-acid detoxification enzymes and transporter proteins. Among these was An14g03570, a putative ABC-type transporter which we found to be required for weak-acid resistance in We also show that An14g03570 is a functional homologue of the protein Pdr12p and we therefore name it PdrA. Last, resistance to sorbic acid was found to be highly heterogeneous within genetically uniform populations of ungerminated conidia, and we demonstrate that is a determinant of this heteroresistance. This study has identified novel mechanisms of weak-acid resistance in which could help inform and improve future food spoilage prevention strategies. Weak acids are widely used as food preservatives, as they are very effective at preventing the growth of most species of bacteria and fungi. However, some species of molds can survive and grow in the concentrations of weak acid employed in food and drink products, thereby causing spoilage with resultant risks for food security and health. Current knowledge of weak-acid resistance mechanisms in these fungi is limited, especially in comparison to that in yeasts. We characterized gene functions in the spoilage mold species which are important for survival and growth in the presence of weak-acid preservatives. Such identification of weak-acid resistance mechanisms in spoilage molds will help in the design of new strategies to reduce food spoilage in the future.
Topics: Acids; Aspergillus niger; Drug Resistance, Fungal; Fungal Proteins; Gene Expression Regulation, Fungal; Microbial Sensitivity Tests; Saccharomyces cerevisiae; Spores, Fungal; Transcription Factors
PubMed: 31915214
DOI: 10.1128/mSphere.00685-19 -
Future Microbiology Mar 2010Since its discovery in 1924 by J Clarke, Streptococcus mutans has been the focus of rigorous research efforts due to its involvement in caries initiation and... (Review)
Review
Since its discovery in 1924 by J Clarke, Streptococcus mutans has been the focus of rigorous research efforts due to its involvement in caries initiation and progression. Its ability to ferment a range of dietary carbohydrates can rapidly drop the external environmental pH, thereby making dental plaque inhabitable to many competing species and can ultimately lead to tooth decay. Acid production by this oral pathogen would prove suicidal if not for its remarkable ability to withstand the acid onslaught by utilizing a wide variety of highly evolved acid-tolerance mechanisms. The elucidation of these mechanisms will be discussed, serving as the focus of this review.
Topics: Acids; Anti-Bacterial Agents; Carbohydrate Metabolism; Streptococcus mutans; Stress, Physiological
PubMed: 20210551
DOI: 10.2217/fmb.09.129 -
Molecules (Basel, Switzerland) Aug 2016The syntheses of hydroxymethylenebisphosphonic acid derivatives (dronic acid derivatives) starting from the corresponding substituted acetic acids and P-reagents, mainly... (Review)
Review
The syntheses of hydroxymethylenebisphosphonic acid derivatives (dronic acid derivatives) starting from the corresponding substituted acetic acids and P-reagents, mainly phosphorus trichloride and phosphorous acid are surveyed according to the solvents applied. The nature of the solvent is a critical point due to the heterogeneity of the reaction mixtures. This review sheds light on the optimum choice and ratio of the P-reactants, and on the optimum conditions.
Topics: Diphosphonates; Molecular Structure; Phosphorous Acids; Solvents
PubMed: 27529200
DOI: 10.3390/molecules21081046 -
BioMed Research International 2021A fluoride-releasing adhesive system is expected to promote mineralization of demineralized dentin/enamel around a composite restoration, thereby contributing to the... (Review)
Review
A fluoride-releasing adhesive system is expected to promote mineralization of demineralized dentin/enamel around a composite restoration, thereby contributing to the longevity of the restoration. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) observations revealed the formation of an "acid-base resistant zone" (ABRZ) beneath the hybrid layer when dentin was treated with a self-etch adhesive system. A thicker ABRZ was formed from the upper slope to the end of the outer lesion, indicating greater resistance against an acid-base challenge, when a fluoride-releasing self-etch adhesive system was used. The slope formation of a fluoride-releasing adhesive is believed to be due to fluoride-release from the adhesive. Quantitative assessment of the acid resistance was performed at the interface using the region of interest (ROI) mode of a digital image analysis software package. The area of the ABRZ is influenced by the concentration of fluoride release from the adhesive resin. The threshold of fluoride concentration in the adhesive may exist to influence the morphology of the ABRZ. X-ray absorption fine structure (XAFS) analysis of the dentin treated with different concentrations of NaF-mouth rinses suggested that different fluoride concentrations result in the formation of different chemical compounds, such as fluorapatite and CaF-like structures, on the dentin surface. This may explain the differences in TBS values and morphological appearance of the ABRZ. NaF is effective in enhancing the enamel/dentin bond durability and also helps create a high quality of ARBZ to improve the clinical success of restorations.
Topics: Acid Etching, Dental; Acids; Adhesives; Alkalies; Dentin; Fluorides
PubMed: 34368356
DOI: 10.1155/2021/9731280