An in-situ FTIR-LCR meter technique to study the sensing mechanism of MnO2@ZIF-8/CNPs and a direct relationship between the sensitivity of the sensors and the rate of surface reaction

DATA AVAILABITY STATEMENT: Data will be made available on request.SUPPORTING INFORMATION: FILE S1: Appendix ADiethylamine vapor is harmful to people if inhaled or swallowed, as it results in the oxidation of hemoglobin in the body into unwanted methemoglobin, which is unable to transport oxygen in the blood, resulting in reduced blood oxygenation. Lack of blood oxygenation leads to hypoxemia. MnO2 nanorods, carbon soot, and MnO2@ZIF-8 are sensing materials used to prepare solid-state gas sensors that operate at room temperature. The prepared sensing materials were characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The performance of the MnO2@ZIF-8 based sensor improved significantly when the carbon soot was introduced into the composite. The effect of the amount of CNPs in the composite on the performance of the sensors was studied. The MnO2@ZIF-8/CNPs-based sensor with a 3:1 mass ratio was highly selective towards diethylamine vapor over acetone, methanol, ethanol, and 3-pentanone vapors. An in situ FTIR coupled with LCR meter was used to understand the sensing mechanism of diethylamine vapor and it was found that the sensing mechanism was by deep oxidation of diethylamine to CO2, H2O, and other molecules. The sensing mechanism was studied by monitored by CO2 band intensity which was produced from the reaction between the sensing materials and the analyte vapor. As the sensor’s exposure time increased the intensity of the CO2 IR band increased. We observed the direct relationship between the surface reaction rate and the sensor’s sensitivity.The University of Johannesburg.https://www.elsevier.com/locate/rinpChemistrySDG-09: Industry, innovation and infrastructur

Synthesis and magnetic properties of a superparamagnetic nanocomposite pectin-magnetite nanocomposite

Magnetic nanocomposites composed of superparamagnetic magnetite nanoparticles in a pectin matrix were synthesized by anin situ coprecipitation method. The pectin matrix acted as a stabilizer and size control host for the magnetite nanoparticles(MNPs) ensuring particle size homogeneity. The effects of the different reactant ratios and nanocomposite drying conditions onthe magnetic properties were investigated. The nanocomposites were characterized by X-ray diffraction (XRD), scanning electronmicroscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transforminfrared (FT-IR) spectroscopy, and superconducting quantum interference device magnetometer (SQUID). Superparamagneticmagnetite nanoparticles with mean diameters of 9 and 13 nm were obtained, and the freeze-dried nanocomposites had a saturationmagnetization of 54 and 53 emu/g, respective

In vitro and in vivo antiestrogenic effects of dichloromethane-methanol extract of Crateva adansonii DC

Abstract: Despite significant developments occurring in the treatment of cancer, it still remains the second deadly disease, responsible for 8.2 million deaths every year. Various natural substances have been studied for active molecules of tumor suppression in the past and the tropical flora, by its diversity, continues to provide new antitumor drugs. Crateva adansonii dichloromethane-methanol (DCM/MeOH) extract was previously reported to prevent breast tumors in Wistar rats. However, it exhibited weak cytotoxic effect in human MCF-7 cells. The present study, therefore, deals with the investigation of its estrogenic and antiestrogenic effects. In vitro estrogenicity and antiestrogenicity of C. adansonii DCM/MeOH extract were performed by E-screen assay. In vivo, the investigation was carried out using the 3 days uterotrophic assay in ovariectomized rats, a classical tool for the prediction of estrogenicity of chemicals. As a result, C. adansonii extract did not induce MCF-7 cells proliferation, which is an estrogenic hallmark. However, C. adansonii extract induced a significant (P <0.05) decrease in a concentration-dependent manner of the MCF-7 proliferation when co-administered with E2B. In vivo, no estrogen-like effect was observed following a 3-day treatment with C. adansonii extract in estrogen target organs. However, the co-administration of C. adansonii extract with E2V lead to decreased uterine wet weight (P <0.05), total protein levels in uteri (P <0.01) as well as uterine and vaginal epithelial heights (P <0.05) as compared to animals treated with E2V only. These results suggest that C. adansonii has antiestrogenic effects but not estrogenic effects, which might account for its previously observed antimammary tumour effects in rats

Antibacterial effects of Alchornea cordifolia (Schumach. and Thonn.) Müll. Arg extracts and compounds on gastrointestinal, skin, respiratory and urinary tract pathogens

Ethnopharmacological relevance:The leaves, stems and roots ofAlchornea cordifolia(Schumach. andThonn.) Müll. Arg. are used as traditional medicine in many African countries for the management ofgastrointestinal, respiratory and urinary tract infections as well as for the treatment of wounds.Aim of the study:To determine the in vitro antibacterial activity of the crude extracts of leaves and stemsofA. cordifoliaon gastrointestinal, skin, respiratory and urinary tract pathogens and to identify thecompounds in the extracts that may be responsible for this activity.Materials and methods:The antibacterial activities of crude extracts [hexane, chloroform (CHCl3), ethylacetate (EtOAc), ethanol (EtOH), methanol (MeOH) and water (H2O)] as well as pure compounds isolatedfrom these extracts were evaluated by means of the micro-dilution assay against four Gram-positivebacteria, i.e.Bacillus cereusATCC 11778,Enterococcus faecalisATCC 29212, Staphylococcus aureusATCC25923 andS. saprophyticusATCC 15305,as well as four Gram-negative bacterial strains, i.e.EscherichiacoliATCC 25922, Klebsiella pneumoniaeATCC 13883, Moraxella catarrhalisATCC 23246 andProteus mir-abilisATCC 43071. The isolation of the active constituents was undertaken by bio-autographic assays inconjunction with chromatographic techniques. The identification and characterisation of the isolatedcompounds were done using mass spectrometry (MS) and Fourier transformed infrared spectrometry(FTIR) as well as 1D- and 2D- nuclear magnetic resonance (NMR) analyses.Results:The leaves and stems ofA. cordifoliaexhibited varied antibacterial activity against all eight pa-thogens. Most of the MIC values ranged between 63 and 2000mg/ml. The highest activities for the crudeextracts (63mg/ml) were observed againstS. saprophyticus[stem (EtOAc, CHCl3and hexane), leaves(MeOH, EtOH, EtOAc and CHCl3)],E. coli[stem (MeOH and EtOH), leaves (MeOH, EtOH, EtOAc andCHCl3)],M. catarrhalis[leaves (EtOAc and CHCl3)],K. pneumoniae[stem (CHCl3), leaves (CHCl3)] andS.aureus[leaves (CHCl3)]. Seven constituents [stigmasterol (1), stigmasta-4,22-dien-3-one (2), friedelin (3),friedelane-3-one-28-al (4), 3-O-acetyl-aleuritolic acid (5), 3-O-acetyl-erythrodiol (6) and methyl-3,4,5-trihydroxybenzoate (methyl gallate) (7)] were isolated from the stem MeOH extract. All these com-pounds displayed some antibacterial activity against the eight pathogens with highest activity againstS.saprophyticus(2mg/ml). Furthermore, this is thefirst report of compounds1,2,3,4,6and7isolated fromA. cordifoliaand where a complete set of 2D-NMR data for fridelane-3-one-28-al (4) is presented.Conclusion:The study demonstrated that the antibacterial activities ofA. cordifoliaextracts may be dueto the presence of the seven isolated compounds, where compounds3–6showed the best activity. Theobserved activity against gastrointestinal, skin, respiratory and urinary tract pathogens supports thetraditional use for the treatment of such ailments

Design of oleanolic acid-based hybrid compounds as potential pharmaceutical scaffolds

BACKGROUND : Infectious diseases, as well as cancer, are the leading causes of death worldwide. Drug resistance usually results in their treatment requiring a combination of two or more drugs. OBJECTIVE : Oleanolic-based hybrid compounds were prepared via esterification and characterized using FTIR, NMR and LC-MS. In vitro antibacterial and in vitro cytotoxicity studies were performed. METHODS : Oleanolic acid was hybridized with selected known pharmaceutical scaffolds via the carboxylic acid functionality in order to develop therapeutics with increased biological activity. Antibacterial activity was determined using the micro-dilution assay against selected Gram-positive and Gram-negative bacteria and cytotoxicity using the sulforhodamine B assay. RESULTS : Compound 8 displayed potent antibacterial effect against five strains of bacteria, such as Bacillus subtilis, Staphylococcus aureus, Proteus vulgaris, Klebsiella oxytoca, and Escherichia coli, with MIC values of 1.25, 0.078, 0.078, 1.25, 1.25 mg/mL when compared to the control, oleanolic acid (MIC = 2.5 mg/mL). Furthermore, in vitro cytotoxicity, as determined using the SRB assay, against selected cancer cells revealed that compound 7 was the most cytotoxic on MDA, DU145, and MCF-7 cell lines with IC50 values of 69.87 ± 1.04, 73.2 ± 1.08, and 85.27 ± 1.02 μg/mL, respectively, compared to oleanolic acid with an IC50 > 200 μg/mL. CONCLUSION : Hybridization of oleanolic acid was successful, and further development of these potential antibacterial compounds with reduced cytotoxicity is therefore warranted.The South African Medical Research Council (Self-Initiated Research), National Research Foundation South African and Govan Mbeki Research and Development Centre (GMRDC), University of Fort Hare.https://benthamscience.com/journals/letters-in-drug-design-and-discoveryhj2023Pharmacolog

Effect of gum extracts on the bread-making and textural properties of dough and bread made from sour cassava starch (Manihot esculenta), Peanut (Arachis hypogaea) and cowpea flour (Vigna unguiculata)

DATA AVAILABILITY : Data will be made available on request.Gluten intolerance, as well as the scarcity of wheat flour in some parts of the world, has prompted the development of gluten-free bread. Gluten-free bread, on the other hand, results in a low specific volume and to remedy this, the use of hydrocolloids and bases has proved to be very successful. The current study aims to determine the optimal proportions of Triumffeta pentendra gum extract and bicarbonate in the breadmaking of a composite flour based on sour cassava starch, peanut flour, and cowpea flour. A Box Benkhen design was used to achieved this, with the variables being the amount of gum extract, the amount of bicarbonate, and the amount of water. The specific volume and texture properties were evaluated as responses. The specific volume was calculated using standard methods, and the textural properties were determined using a texture analyzer. It appears that the incorporation of gums extract, bicarbonate, and water significantly increased the specific volume. The incorporation rate of gum extract significantly increases the hardness, consistency, and masticability which decreases with the incorporation rate of bicarbonate and water. Cohesion and elasticity, on the other hand, increased with the incorporation rate of bicarbonate and water but decreased with the incorporation of gum extract. The optimal gum extract, bicarbonate, and water proportions are 0.28 g, 1.99 g, and 112.5 ml, respectively. As a result, the specific volume is 1.51cm3/g, the hardness is 38.51(N), the cohesion is 0.88, the consistency is 32.86(N), the elasticity is 5.57(1/L), and the masticability is 162.35(mj). According to this findings, gum extracts and sodium bicarbonate can be used to improve the quality of gluten-free bread made with sour cassava starch, peanut and cowpea flour.https://www.elsevier.com/locate/fhfhhj2024Consumer ScienceFood ScienceSDG-02:Zero Hunge

Optimization of the processing conditions for the production of a gluten-free bread from Sour Cassava starch (Manihot esculenta) and some legumes (Arachis hypogaea, Vigna unguiculata, and Glycine max)

DATA AVAILABILITY STATEMENT : The datasets generated for this study are available on request to the corresponding author.BACKGROUND : Sour cassava starch is used as an alternative to wheat flour in breadmaking. However, its nutritional and technological properties are limited. To remedy this, the use of legumes has proved to be very successful. Thus, the present study aimed to determine the optimal condition for the production of bread made from sour cassava starch, peanut, cowpea and soybean flour. METHODS : The I-optimal design was employed to obtain an optimal proportion of the mixture with the variables sour cassava starch, cowpea, soy and peanut flour. The responses evaluated were overall acceptability, specific volume and protein content. RESULTS : It resulted that the incorporation of sour cassava starch positively influenced the volume but negatively influenced the protein content and overall acceptability. While the addition of legumes increased protein content and overall consumer acceptability, the specific volume was reduced. The optimal proportions of sour cassava starch, cowpea, soybean and peanut flour were 64.11%, 18.92%, 0% and 16.96%, respectively. Under this condition, it led to a desirability of 1, specific volume of 1.35, overall acceptability of 6.13, protein content of 9.72%, carbohydrate content of 67.89%, fat content of 9.39%, fiber content of 2.10% and ash content of 1.04%. CONCLUSIONS : The findings suggest that cowpea and peanut can be used for the improvement of the technological, nutritional and sensory properties of sour cassava starch bread and thus increase its consumption and application in the food processing industry.The Article Processing Charge (APCs) is solely paid by the University of Johannesburg.https://www.mdpi.com/journal/foodsam2024Consumer ScienceFood ScienceSDG-02:Zero Hunge

Selective detection of methanol vapour from a multicomponent gas mixture using a CNPs/ ZnO@ZIF-8 based room temperature solid-state sensor

Methanol vapour is harmful to human health if it is inhaled, swallowed, or absorbed through the skin. Solidstate gas sensors are a promising system for the detection of volatile organic compounds, unfortunately, they can have poor gas selectivity, low sensitivity, an inferior limit of detection (LOD), sensitivity towards humidity, and a need to operate at higher temperatures. A novel solid-state gas sensor was assembled using carbon nanoparticles (CNPs), prepared from a simple pyrolysis reaction, and zinc oxide@zeolitic imidazolate framework-8 nanorods (ZnO@ZIF-8 nanorods), synthesised using a hydrothermal method. The nanomaterials were characterized using scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy Raman spectroscopy, and Fourier transform infrared spectroscopy. The ZnO@ZIF-8 nanorods were inactive as a sensor, the CNPs showed some sensor activity, and the CNPs/ZnO@ZIF-8 nanorod composite performed as a viable solidstate sensor. The mass ratio of ZnO@ZIF-8 nanorods within the CNPs/ZnO@ZIF-8 nanorod composite was varied to investigate selectivity and sensitivity for the detection of ethanol, 2-propanol, acetone, ethyl acetate, chloroform, and methanol vapours. The assembled sensor composed of the CNPs/ ZnO@ZIF-8 nanorod composite with a mass ratio of 1.5 : 6 showed improved gas sensing properties in the detection of methanol vapour with a LOD of 60 ppb. The sensor is insensitive to humidity and the methanol vapour sensitivity was found to be 0.51 U ppm 1 when detected at room temperature.http://pubs.rsc.org/en/journals/journalissues/raam2023Chemistr

An in-situ FTIR-LCR meter technique to study the sensing mechanism of MnO2@ZIF-8/CNPs and a direct relationship between the sensitivity of the sensors and the rate of surface reaction

Diethylamine vapor is harmful to people if inhaled or swallowed, as it results in the oxidation of hemoglobin in the body into unwanted methemoglobin, which is unable to transport oxygen in the blood, resulting in reduced blood oxygenation. Lack of blood oxygenation leads to hypoxemia. MnO2 nanorods, carbon soot, and MnO2@ZIF-8 are sensing materials used to prepare solid-state gas sensors that operate at room temperature. The prepared sensing materials were characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The performance of the MnO2@ZIF-8 based sensor improved significantly when the carbon soot was introduced into the composite. The effect of the amount of CNPs in the composite on the performance of the sensors was studied. The MnO2@ZIF-8/CNPs-based sensor with a 3:1 mass ratio was highly selective towards diethylamine vapor over acetone, methanol, ethanol, and 3-pentanone vapors. An in situ FTIR coupled with LCR meter was used to understand the sensing mechanism of diethylamine vapor and it was found that the sensing mechanism was by deep oxidation of diethylamine to CO2, H2O, and other molecules. The sensing mechanism was studied by monitored by CO2 band intensity which was produced from the reaction between the sensing materials and the analyte vapor. As the sensor's exposure time increased the intensity of the CO2 IR band increased. We observed the direct relationship between the surface reaction rate and the sensor's sensitivity

Nickel Oxide-Carbon Soot-Cellulose Acetate Nanocomposite for the Detection of Mesitylene Vapour: Investigating the Sensing Mechanism Using an LCR Meter Coupled to an FTIR Spectrometer

Nanocomposite sensors were prepared using carbon soot (CNPs), nickel oxide nanoparticles (NiO-NPs), and cellulose acetate (CA), which was used to detect and study the sensing mechanism of mesitylene vapour at room temperature. Synthesised materials were characterised using high-resolution transmission electron microscopy (HR-TEM), powder x-ray diffraction (PXRD), Raman spectroscopy, and nitrogen sorption at 77 K. Various sensors were prepared using individual nanomaterials (NiO-NPs, CNPs, and CA), binary combinations of the nanomaterials (CNPs-NiO, CNPs-CA, and NiO-CA), and ternary composites (NiO-CNPs-CA). Among all of the prepared and tested sensors, the ternary nanocomposites (NiO-CNPs-CA) were found to be the most sensitive for the detection of mesitylene, with acceptable response recovery times. Fourier-transform infrared (FTIR) spectroscopy coupled with an LCR meter revealed that the mesitylene decomposes into carbon dioxide