Physical-chemical Aspects Research Articles

WATER QUALITY ASSESSMENT IN KHLONG THAWI WATTHANA, THAILAND: PHYSICAL, CHEMICAL, AND MICROBIOLOGICAL ANALYSIS

The physical, chemical, and microbiological quality of the canal water in Khlong Thawi Watthana was analyzed in a study conducted with the aim of benefiting the local community surrounding Bangkokthonburi University. Potential measures to prevent and address water quality issues could be identified through this study by providing information about the canal’s water quality. Standard methods (APHA, AWWA, and WPCF) were used to analyze the water quality, considering physical parameters such as turbidity, water temperature, and color, and examining chemical parameters including electrical conductivity, pH levels, total suspended solids (TSS), total dissolved solids (TDS), and dissolved oxygen (DO). In addition, biochemical oxygen demand (BOD), total phosphorus, and Total Kjeldahl Nitrogen (TKN) were assessed. Moreover, the drug sensitivity of bacteria present in the water samples of the Thawi Watthana canal was studied, particularly cephalosporin and carbapenems, for medical purposes, employing the standard disk diffusion method for antibiotic susceptibility testing. The experimental results indicated that the physical analysis values and chemical aspects were within the water quality standards, including the analysis of heavy metal concentrations such as Mn, Cd, Fe, and Pb. However, the standard limits were exceeded for total coliform bacteria (TCB) (Escherichia, Citrobacter, Enterobacter, Hafnia, Klebsiella, Serratia) in all areas, particularly in front of Thaweesup Market, Bangkokthonburi University, and Pratunam Canal. The presence of community and educational institutions and related businesses and sewage may have contributed to these findings. The study was conducted between January and March, which represents only the rainy or hot season. The analysis of all three types of antibiotics revealed that cephalosporin antibiotics such as ceftriaxone and carbapenems such as meropenem and ertapenem were effective in preventing bacterial growth in the canal water.

Optimizing Drying Conditions for Lotus Flowers and Characterization of the Chemical and Functional Properties of Lotus Flower Powder for Food Applications

The lotus (Nelumbo nucifera) is an aquatic plant that holds religious and cultural significance. Additionally, it provides an important source of vital nutrients and antioxidants. The present study aimed at examining the physical characteristics, drying temperatures, and chemical and functional aspects of lotus flower powder. The findings revealed a wide range of the weight, length, and width of lotus flowers, which may be linked to several factors like age, conditions in the environment, and genetic diversity. The flowers subjected to drying methods like tray drying and shade drying. In tray drying the samples were subjected to different temperatures viz., 40°C, 50°C, 60°C and 70°C. Drying was continued till the flowers became completely dry and crisp and also until constant weight attained. The colour of the lotus flower powder was shown to be significantly influenced by the drying temperature. The lowest lightness value (L*) was observed at 40 °C and the highest lightness value (L*) was observed at 50°C. Whereas, lotus subjected to a drying temperature of 60 °C exhibited a similar resemblance to the colour values of fresh lotus petals, suggesting a high degree of retention of the red colour. The lotus flower powder was found to possess a slightly acidic pH, a high water holding capacity (WHC), and a moderate oil holding capacity (OHC), as determined through chemical and functional analysis. Emulsifying and foaming properties of lotus powder indicated its potential for use in food products. Overall, this study provides valuable insights into the physical, drying, and chemical properties of lotus flowers, shedding light on their potential applications in various functional foods.

STUDY OF DIKE EFFECTS TO CONTROL SEDIMENTATION PROCESS ON PATIMBAN'S PORT PLAN USING COMPUTATION MODELING

The development of the international port of Patimban in Subang is very urgent. The port is expected to support the Tanjung Priok port in Jakarta which is unable to meet the loading and unloading needs of business operators, especially in West Java. In port development planning one of the main problems of physical chemical aspects is sedimentation and erosion process. The purpose of this modeling is to know the sedimentation and erosion pattern around the location plan of port development. The result of modeling is expected to be the initial consideration in designing the Patimban Port. Modeling of sediment transport is done by using MIKE21 Sand Transport module software by entering geophysical data of field survey result such as bathymetry, sea level, river flow and characteristic of existing sediment. Modeling is done both in west season and east season for 1 year (October 2016-September 2017). Based on the result of point extraction on the modeling result, it is known that the influence of dike significantly reduces the bed level change in the harbor channel about 46.45 - 82.28% (for dike 2 m) and about 55.01 - 88.94% (for dike 4 m). While, based on the result of the area extraction, it is known that the influence of the dike on the bed level change in the harbor channel is significant, that is to decrease the average of bed level change by 77.58% (for dike 2m) and 81.02% (for dike 4m).

A new perspective on thermal aspects of physical chemistry and materials science in Central-Eastern Europe region

A new perspective on thermal aspects of physical chemistry and materials science in Central-Eastern Europe region

Impact of Sugar Reduction on Physicochemical and Nutritional Quality of Yogurt and Sensory Response with Label Stimulation

This paper is aimed at developing yoghurts with reduced sugar content and evaluating their physicochemical, microbiological, and sensory characteristics including the stimulation of labels with nutritional indications. Four yoghurt formulations were developed (TY (traditional yoghurt), RSY (reduced sugar yoghurt), RSYL (yoghurt with reduced sugar and lactase), and RSYM (yogurt with reduced sugar and flavour modulator)). Yoghurts were evaluated on the first day of storage for physical-chemical aspects: fat, total protein, ash, total dry extract, reducing and nonreducing sugars, and pH, acidity in lactic acid, syneresis, and viscosity (non-Newtonian fluid) parameters were monitored until the end of refrigerated storage. Online questionnaires were carried out for sensory evaluation of acceptability and purchase intention of appearance. The labels were compared to each other to define which one communicated best with the consumer. The results showed that the reduction of sugar in yoghurt interferes with different physical-chemical parameters: pH, acidity, increasing syneresis, decreasing viscosity, total dry extract, and ash content. Storage influences the pH and acidity stabilization of all yogurts. Knowledge about lower sugar content positively influences acceptability and purchase intention, which preferred more flashy nutritional labels. The formulation adjustment associated with adequate labeling can encourage the consumption of yogurts with reduced added sugar content.

Targeted Nuclear Medicine. Achievements, Challenges and Prospects

The path of the development of nuclear medicine at the international level and that in Russia is presented. Significant achievements in the development and establishment of nuclear-physics technologies and the development of targeted radiopharmaceuticals (RPs) are presented. The main directions of targeted nuclear medicine are shown. The physical–chemical aspects of the synthesis of radiopharmaceuticals are considered, and the advantages and specificity of vector carrier molecules are shown.

Tracking new insights into antifungal and anti-mycotoxigenic properties of a biofilm forming Pediococcus pentosaceus strain isolated from grain silage

The present study offers detailed insights into the antifungal and anti-mycotoxigenic potential of a biofilm forming lactic acid bacterium (Pediococcus pentosaceus) against one atoxigenic (Aspergillus flavus) and two toxigenic (Aspergillus nomius and Fusarium verticillioides) fungal strains. The antifungal effect of P. pentosaceus LBM18 strain was initially investigated through comparative analysis of fungi physiology by macroscopic visual evaluations and scanning electron microscopy examinations. The effects over fungal growth rate and asexual sporulation were additionally accessed. Furthermore, analytical evaluations of mycotoxin production were carried out by HPLC-MS/MS to provide insights on the bacterial anti-mycotoxigenic activity over fungal production of the aflatoxins B1, B2, G1 and G2 as well as fumonisins B1 and B2. Finally, reverse transcription quantitative real-time PCR (RT-qPCR) analysis was employed at the most effective bacterial inoculant concentration to evaluate, at the molecular level, the down-regulation of genes aflR, aflQ and aflD, related to the biosynthesis of aflatoxins by the strain of Aspergillus nomius. The effects over mycotoxin contamination were thought to be result of a combination of several biotic and abiotic factors, such as interaction between living beings and physical-chemical aspects of the environment, respectively. Several possible mechanisms of action were addressed along with potentially deleterious effects ascribing from P. pentosaceus misuse as biopesticide, emphasizing the importance of evaluating lactic acid bacteria safety in new applications, concentrations, and exposure scenarios.

Diversified crop rotations and organic amendments as strategies for increasing soil carbon storage and stabilisation in UK arable systems

Adaptations in crop rotation with the inclusion of temporary grass-clover leys and organic amendments, have been promoted as effective ways to improve soil carbon (C) sequestration and mitigate climate change in agricultural systems. However, there are still a lot of uncertainties related to i) the combined effects of different crop rotations and different fertilisation sources, e.g., organic amendments, on soil C stocks; and ii) their potential effect on C stabilisation. The objective of this study was to evaluate the effect of different arable crop rotations with varying degrees of diversity in crop type and lengths of grass-clover ley periods and fertilisation sources on soil C stocks and C stabilisation down to 0.60 m soil depth. This was investigated in a long-term factorial field experiment-combining different crop rotation (cereal-intensive conventional vs. diversified legume-intensive organic) with different lengths of grass-clover ley periods (2 vs. 3 years), fertilisation sources (mineral vs. compost), and years (samples taken at the beginning and at the last year of one complete cycle of rotation; 8 years apart)-to explore their individual and interactive effect on soil C stock and C stabilisation at two soil depths (0–0.30 and 0.30–0.60 m). Soil C stabilisation was assessed using a unique combination of three different techniques: physical fractionation for separation of C associated to organic and mineral fractions, thermal analysis combined with differential scanning calorimetry and a quadrupole mass spectrometry (TG-DSC-QMS) for physical-chemical aspects, and pyrolysis coupled with gas chromatography-mass spectrometry (Py-GC/MS) for molecular structural information. The findings showed higher soil C stocks under the diversified organic rotation with 3 years of grass-clover ley period at both soil depths, regardless of the fertilisation source or sampling year. However, the organic rotation seemed to deliver stable soil C stocks only in the subsoil layer. Compost fertilisation, in turn, increased topsoil C stocks between the two sample dates under both rotations, and it appears to be stable. These results suggested that combining a diversified organic rotation with 3 years grass-clover ley with compost fertilisation could be one way for agricultural systems to deliver stable soil C sequestration.

A novel nanocomposite containing zinc ferrite nanoparticles embedded in carboxymethylcellulose hydrogel plus carbon nitride nanosheets with multifunctional bioactivity.

A novel and biologically active nanobiocomposite is synthesized based on carbon nitride nanosheet (g-C3N4) based carboxymethylcellulose hydrogels with embedded zinc ferrite nanoparticles. Physical-chemical aspects, morphological properties, and their multifunctional biological properties have been considered in the process of evaluation of the synthesized structure. The hydrogels' compressive strength and compressive modulus are 1.98 ± 0.03 MPa and 3.46 ± 0.05 MPa, respectively. Regarding the biological response, it is shown that the nanobiocomposite is non-toxic and biocompatible, and hemocompatible (with Hu02 cells). In addition, the developed material offers a suitable antibacterial activity for both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).

Habitat and abundance of <i>Aegla papudo</i> (Decapoda: Anomura: Aeglidae) at two new record sites

Aegla papudo is a freshwater crab endemic to Chile. Although known to inhabit turbid watercourses with gravel, sand, filamentous algae, leaf litter, and no tree cover; however, is scarce the information on the proportions of these components, physical-chemical aspects of the water, population abundance, and reproductive season. Its presence in the Cordillera El Melon led us to describe the habitat. Between 2018 and 2019, the species was searched for in seven streams. Its habitat was described, the density calculated, the water’s physical-chemical parameters recorded. The variable that explained the abundance was analyzed with a model of Poisson. The species was recorded in the Los Coiles and El Gallo streams (62 and 24 individuals respectively) with a mean density of 1 individual/m2. The abundance was explained by the volume of the mud with gravel and pebble. This investigation is the first to determinethe abundance of adults and juveniles, as well as the variable that explained it. Environments with transparent water and tree cover are new aspects of the habitat. Fecal coliforms varied remarkably. Juvenile individuals present in August suggest that reproduction takes place between summer and fall. The International Union for Conservation of Nature does not register the species; however, we agree with other researchers who propose that the species be classified as Endangered due to known threats.

Yellow Mombin Nectar Enriched with Encapsulated Green Tea (Camellia Sinensis Var Assamica): Physical-chemical, Rheological and Sensory Aspects

ABSTRACT This research aimed to evaluate the feasibility of applying green tea extract encapsulated in yellow mombin (Spondias mombin L.) nectar. Two formulations were developed: with microencapsulated green tea extract (NM) and control (NC). NM was the variant concentration of green tea microencapsulated (4.6 g of green tea microcapsules for each 240 mL of beverage). The samples were subjected to physical-chemical and bioactive compounds analysis, such as the study of rheological behavior and sensory analysis. The addition of microcapsules resulted in changes in all of the parameters evaluated, highlighting the contribution in antioxidant activity and total phenolic compounds. The inclusion of microcapsules did not influence the rheological behavior. For the sensory analysis, it was found that NC presented better sensory acceptance. The inclusion of microcapsules of green tea extract in yellow mombin nectar presents itself as a viable alternative for the development of a new product.

Zn2+ induced self-assembled fabrication of marigold-like ZnO microflower@Ni(OH)2 three-dimensional nanosheets for nonenzymatic glucose sensing

Precise control over the structure and morphology of nano/microarchitectures is the topic of immense interest to tune their physical features and chemical aspects for desired applications. In this work, a novel and effective Ni(OH)2 three-dimensional nanosheet-coated marigold-like ZnO microflower (mg-ZnO@Ni(OH)2 NSs) hybrid is designed for the nonenzymatic electrochemical determination of glucose. The morphological evolution of mg-ZnO and mg-ZnO@Ni(OH)2 NSs was achieved by a one-pot solvothermal strategy through control over the reaction conditions without any assistance of an external shape-controlling surfactant. Furthermore, the as-fabricated mg-ZnO and mg-ZnO@Ni(OH)2 NSs were systematically evaluated by different spectroscopic, microscopic and electrochemical characterization tools. The results indicate that highly exposed homogeneous nanocorners of mg-ZnO and the synergetic effect of Ni(OH)2 coating, collectively improve the electrocatalytic efficiency of the designed catalyst. The mg-ZnO@Ni(OH)2 NS-based sensing electrode exhibits excellent amperometric performance for glucose monitoring, comprising satisfactory sensitivity (259.78 and 62.82 μA mM−1 cm−2), wide linear range (0.084–0.941 mM and 0.941–6.50 mM), low limit of detection (0.06 µM, S/N = 3), good stability and high detection selectivity. Moreover, the designed sensor is promising for the potential application in the real-time glucose detection of human serum samples.

Parasitological, microbiological, and antimicrobial resistance profiles of raw and drinking water in a tourist city in the tri-border region of South America.

Despite the large amounts of freshwater available in Brazil, the deterioration of surface water can represent a risk of waterborne disease for national and international tourists. The main goal of this study was to assess the quality of drinking water in the triple border region of Brazil before and after being treated in water treatment plants (WTPs) and in Municipal Early Childhood Education Centers (MECECs), in terms of parasitological, microbiological, and physical-chemical aspects. Different water samples were monitored: raw water (RW), treated water (TW), and tap water from the MECECs, giving 60 samples in total, to investigate the presence of Giardia and Cryptosporidium, microbiological indicators, Pseudomonas aeruginosa, and antimicrobial resistance profiles using conventional microbiological assays and parasitological, immunological, and molecular techniques. The results obtained were compared with the reference values recommended by the legislation of drinking water in Brazil. For the first time, contamination by Cryptosporidium and Giardia was demonstrated in RW used to supply WTPs, in TW of Foz do Iguaçu, and in water destined for consumption by children. A total of 52 bacterial isolates were obtained, with high percentages of multidrug resistance to antibiotics, including a carbapenem-resistant profile, highlighting the need to improve quality control standards.

Natural Polyphenol-Containing Gels against HSV-1 Infection: A Comparative Study.

Herpes simplex virus type 1 infection commonly affects many people, causing perioral sores, as well as severe complications including encephalitis in immunocompromised patients. The main pharmacological approach involves synthetic antiviral drugs, among which acyclovir is the golden standard, often leading to resistant virus strains under long-term use. An alternative approach based on antiviral plant-derived compounds, such as quercetin and mangiferin, demonstrated an antiviral potential. In the present study, semisolid forms for cutaneous application of quercetin and mangiferin were designed and evaluated to treat HSV-1 infection. Phosphatidylcholine- and poloxamer-based gels were produced and characterized. Gel physical–chemical aspects were evaluated by rheological measurements and X-ray diffraction, evidencing the different thermoresponsive behaviors and supramolecular organizations of semisolid forms. Quercetin and mangiferin diffusion kinetics were compared in vitro by a Franz cell system, demonstrating the different gel efficacies to restrain the polyphenol diffusion. The capability of gels to control polyphenol antioxidant potential and stability was evaluated, indicating a higher stability and antioxidant activity in the case of quercetin loaded in poloxamer-based gel. Furthermore, a plaque reduction assay, conducted to compare the virucidal effect of quercetin and mangiferin loaded in gels against the HSV-1 KOS strain, demonstrated the suitability of poloxamer-based gel to prolong the polyphenol activity.

Physical-Chemical Aspects of the Preparation and Drug Release of Electrospun Scaffolds.

Fibers were spun from a mixture of dichloromethane (DCM) and dimethyl sulfoxide (DMSO) solution of poly(lactic acid)(PLA) containing various amounts of amoxicillin (Amox) as the active component. Composition changes during spinning, structure, solubility, and the location of the drug were considered during the evaluation of drug release and microbial activity. The results showed that the composition of the material changes during the preparation procedure. The solubility of the drug in the components and that of the components in each other is limited, which results in the formation of several phases and the precipitation of the drug. The technology used results in the partitioning of the drug; some is located inside, while the rest is among the fibers. The wetting of the fibers or disks by the water-based dissolution media is poor, the penetration of the liquid into and the diffusion of the active component out of the device takes considerable time. Drug release takes place in one, burst-like step, only Amox located among the fibers dissolve and diffuse into the surrounding medium. The slow second stage of release claimed in the literature is less probable because the size of the Amox molecule is considerably larger than the holes creating the free volume of the polymer. The prepared device has antimicrobial activity, inhibits the growth of the two bacterial strains studied. The time scale of activity is short and corresponds to that of the release experiments and the burst-like behavior of the device. The results clearly prove that physical–chemical factors play a determining role in the effect and efficiency of medical devices prepared from electrospun fibers containing an active component.

Presence and growth prediction of Staphylococcus spp. and Staphylococcus aureus in Minas Frescal cheese, a soft fresh cheese produced in Brazil

Physical-chemical characteristics of Minas Frescal cheese (MFC) favor the growth of Staphylococcus spp. and allow the production of enterotoxins by specific strains. Here, we aimed to characterize the physical-chemical aspects (pH, storage temperature, and salt content) and the presence of Staphylococcus spp. in MFC samples (n = 50) to support a modeling study for the growth by this microorganism. Coagulase-positive staphylococci isolates were obtained and subjected to PCR assays to identify them as Staphylococcus aureus (nuc) and to detect staphylococcal enterotoxin-related genes (sea, seb, sec, sed, see). Staphylococcus aureus growth kinetics (maximum growth rate, Grmax, and lag time) were predicted based on ComBase model and MFC physical-chemical aspects. Mean counts of Staphylococcus spp. ranged from 3.3 to 6.7 log cfu/g, indicating poor hygiene practices during production. Selected isolates (n = 10) were identified as S. aureus, but none presented classical enterotoxin-related genes. pH, temperature, and salt content ranged from 5.80 to 6.62, 5°C to 12°C, and 0.85% to 1.70%, respectively. The Grmax values ranged from 0.012 to 0.419 log cfu/g per h. Independent of the storage temperature, the lowest Grmax values (0.012 to 0.372 log cfu/h) were obtained at pH 5.80 associated with salt content of 1.7%; independent of the pH and salt content, the best temperature to avoid staphylococcal growth was 7.5°C. Hygienic conditions during MFC production must be adopted to avoid staphylococcal contamination, and storage at temperatures lower than 7.5°C can prevent staphylococcal growth and the potential production of enterotoxins.

Post-Harvest Quality and Sensory Evaluation of Mini Sweet Peppers

Sweet pepper (Capsicum annuum L.) is one of the most consumed vegetables in the world, being recognized as a food with high nutritional value. Recently, the market for sweet and colorful mini peppers has increased, especially among the most demanding consumers in the novelties in vegetables and functional foods. In this sense, we evaluated mini sweet peppers genotypes (Akamu, Kaiki, Kalani, Kaolin e Moke from Isla® seeds) regarding the physical-chemical, nutritional and sensory analysis aspects. A wide variability was observed among genotypes, highlighting the Kalani genotype for total carotenoids, and the genotypes Akamu, Kaiki and Kaolin for phenolic totals content and antioxidant activity. Moke and Kaolin showed higher vitamin C content and fruit firmness. Based on sensory analysis, Kalani, Kaiki, Kaolin and Akamu obtained greater global acceptance. The genotypes can be considered an important marketing strategy of mini sweet peppers trade, associating different shapes, colors and nutritional quality.

Sensory characterization of conventional and organic extra virgin olive oil by Check‐all‐that‐apply and emotional responses methods

AbstractThis study aimed to investigate the sensory characterization of commercial and organic extra virgin olive oils by the Check‐all‐that‐apply (CATA) and emotional responses methodologies. The samples were evaluated for viscosity and yellow color by 120 consumers using CATA, acceptance test, purchase intention test, emotional responses, and ideal scaling, allowing the construction of two External Preference Maps aimed to associate the results from the overall impression with the terms from CATA and the emotional responses. The samples Conventional 2 and Organic 2 presented greater proximity with positive descriptors and emotions, while the samples Conventional 4 and Organic 4 were correlated with negative descriptors and emotions, which was also observed in the acceptance and purchase intention tests, showing the consumers' preference for softer products.Practical applicationThe results of this study showed that most consumers do not like the bitterness and piquancy present in olive oils. For them, the oil should be sensorially smooth. In return, they want to buy olive oils of the highest nutritional quality. This demonstrates that, most consumers are laymen and do not know that the greater the bitterness and spiciness the greater the presence of bi‐active compounds present in the products. This study makes it evident that we must inform consumers about how the sensory part is related to physical–chemical aspects of products. With the end of the study, it would be interesting for future studies, to identify the bioactive compounds present in the studied samples and to interrelate with the available sensory results.

Roadmap towards solar fuel synthesis at the water interface of liposome membranes.

Artificial photosynthesis has experienced rapid developments aimed at producing photocatalytic systems for the synthesis of chemical energy carriers. Conceptual advances of solar fuel systems have been inspired by improved understanding of natural photosynthesis and its key operational principles: (a) light harvesting, (b) charge separation, (c) directional proton and electron transport between reaction centres and across membranes, (d) water oxidation and (e) proton or CO2 reduction catalysis. Recently, there has been a surge of bio-inspired photosynthetic assemblies that use liposomes as nanocompartments to confine reaction spaces and enable vectorial charge transport across membranes. This approach, already investigated in the 1980s, offers in principle a promising platform for solar fuel synthesis. However, the fundamental principles governing the supramolecular assemblies of lipids and photoactive surfactant-like molecules in membranes, are intricate, and mastering membrane-supported photochemistry requires thorough understanding of the science behind liposomes. In this review, we provide an overview of approaches and considerations to construct a (semi)artificial liposome for solar fuel production. Key features to consider for the use of liposomes in solar fuel synthesis are highlighted, including the understanding of the orientation and binding of different components along the membrane, the controlled electron transport between the reaction centres, and the generation of proton gradients as driving force. Together with a list of experimental techniques for the characterisation of photoactive liposomes, this article provides the reader with a roadmap towards photocatalytic fuel production at the interface of lipid membranes and aqueous media.

OXIGÊNIO NO CONTEXTO DA COVID-19: O QUE SABEMOS SOBRE A MOLÉCULA QUE RESPIRAMOS E O PAPEL CENTRAL DA QUÍMICA

OXYGEN IN THE COVID-19 CONTEXT: WHAT WE KNOW ABOUT THE MOLECULE WE BREATHE AND THE CENTRAL ROLE OF CHEMISTRY. In this work, the role of chemistry in the coronavirus disease 2019 (COVID-19) pandemic is highlighted through the medical oxygen supply crises in Brazil, as an example of oxygen utility in health. Starting from oxygen chemical characterization, the oxygen cycle in nature is discussed to show how oxygen is formed through photosynthesis, followed by the description of the industrial oxygen production from atmospheric air, including physical-chemical aspects. The use of medical oxygen concentrator is presented and how this device works from the chemical point of view. Besides, the noninvasive and painless oximetry is described in terms of how oxygen saturation level in blood is measured using LED - light emitting diode.