Physicochemical Characteristics Research Articles

Purine, nucleoside, and DNA nitration by peroxynitrite: Mechanistic considerations

Nitro-oxidative stress affects DNA, leading to special chemical modifications of nucleobases and deoxyribose, impacting DNA integrity and stability. Because of the importance of the topic, the state of the knowledge on purine, nucleoside, and DNA nitration by the reactive nitrogen species peroxynitrite was reviewed. Following a description of the chemical and physicochemical characteristics of purines and peroxynitrite, purine nitro-oxidation and its products, the reaction mechanisms, and the recently reported kinetic behavior of 8-NitroGua formation are discussed. Moreover, novel computational studies report structural and conformational DNA changes resulting from the formation of guanine nitration products. Given the relevance of the subject, surprisingly few publications deal with this topic, even considering the past five years.

Synthesis and Characterization of a Magnetic Molecular Imprinted Polymer for Tetracycline Quantification in Food Samples

AbstractIn the present work, we synthesized and tested a magnetic molecularly imprinted polymer (mag‐MIP) sensor for the detection of tetracycline in food samples. High‐performance liquid chromatography (HPLC) and spectrofluorometry were employed for tetracycline determination. The mag‐MIP was polymerized on the surface of Fe3O4@SiO2 magnetic nanoparticles using the following substances: 4 mmol of methacrylic acid as the functional monomer, 20 mmol of ethylene glycol dimethacrylate (EGDMA) as the cross‐linking agent, 82.5 mg of benzoyl peroxide as the radical initiator, and 30 ml of acetonitrile as the solvent. The physicochemical characteristics of the proposed mag‐MIP, including adsorption capabilities and selectivity, were studied and compared with those of a magnetic non‐molecularly imprinted polymer (mag‐NIP). The analytical curve was constructed in the range of 1.0×10−5–8.0×10−5 mol L−1, LOD: 3.3×10−6, LOQ: 1.1×10−5 mol L−1. The results obtained from the adsorption analysis showed that the highest adsorption capacity of the mag‐MIP at equilibrium was 8.247 mg g−1 and that the tetracycline adsorption process followed the Langmuir adsorption isotherm model and pseudo‐second‐order reaction kinetics. The proposed mag‐MIP also exhibited good results when subjected to fluorescence analysis; an increase in tetracycline concentration resulted in an increase in the adsorption capacity, and this led to the effective removal of tetracycline with the reduction of fluorescence intensity. The applicability of the proposed mag‐MIP was evaluated in honey, cow milk, and egg samples through recovery tests conducted using samples containing spiked tetracycline concentration at two different concentration levels (1.7×10−5 and 2.5×10−5 mol L−1), where we obtained recovery percentages in the range of 73.2–87.2 % (HPLC) and 90.5–103.7 % (spectrofluorometry).

Physicochemical Characteristics of Water in the Bontanga Irrigation Dam in the Guinea Savannah Agro-Ecological Zone of Ghana

Fresh water resource is one of the most significant natural assets of a country. Irrigation dams are usually used for irrigation purposes and also often serve as a source of water for domestic use. Due to this, there is a need for proper maintenance, assessment, and sustainable use of irrigation dams. This study assessed the physicochemical properties of the water in the reservoir of Bontanga irrigation dam situated in the Guinea Savannah Agro-Ecological Zone of Ghana. The study assessed four (4) physical and fourteen (14) chemical water quality parameters of the water for irrigation to know whether they are within the acceptable threshold set by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). Sampling techniques used in this study were stratified and purposive samplings. The reservoir of the dam was divided into nine (9) strata and in each stratum, 5 samples were taken making a total of 45 samples. Samples taken in each strata were composited making it a total of 9 samples. The water samples were collected into well-labelled polythene bottles and kept in an ice chest with ice cubes. The samples were transported to the Ecological Laboratory of the University of Ghana for analysis. The parameters analyzed were pH, electrical conductivity (EC), temperature, total dissolved solutes (TDS), chloride (Cl-), sulphate (SO42-), bicarbonate (HCO3-), carbonate, PO4-P, nitrites/nitrate (NO3-N), total dissolved solids (TDS), magnesium (Mg2+), calcium (Ca2+), sodium (Na+), boron, total alkalinity, ammonia (NH4-N) and potassium (K+). A greater percentage of the results obtained were within acceptable limits except potassium which was slightly higher. This could be the result of farming activities in the catchment of the dam. In general, the water in Bontanga irrigation dam can be considered suitable for irrigation purposes.

Phylum-level studies of bacterial cutinases for unravelling enzymatic specificity toward PET degradation: an in silico approach.

The overwhelming use of PET plastic in various day-to-day activities led to the voluminous increase in PET waste and growing environmental hazards. A plethora of methods have been used that are associated with secondary pollutants. Therefore, microbial degradation of PET provides a sustainable approach due to its versatile metabolic diversity and capacity. The present work highlights the cutinase enzyme's role in PET degradation. This study focuses on the bacterial cutinases homologs screened from 43 reported phylum of bacteria. The reported bacterial cutinases for plastic degradation have been chosen as reference sequences, and 917 sequences have shown homology across the bacterial phyla. The dienelactone hydrolase (DLH) domain was identified for attaining specificity towards PET binding in 196 of 917 sequences. Various computational tools have been used for the physicochemical characterization of 196 sequences. The analysis revealed that most selected sequences are hydrophilic, extracellular, and thermally stable. Based on this analysis, 17 sequences have been further pursued for three-dimensional structure prediction and validation. The molecular docking studies of 17 selected sequences revealed efficient PET binding with the three sequences derived from the phylum Bacteroidota, the lowest binding energy of -5.9kcal/mol, Armatimonadota, and Nitrososphaerota with -5.8kcal/mol. The two enzyme sequences retrieved from the phylum Bacteroidota and Armatimonadota are metagenomically derived. Therefore, the present studies concluded that there is a high probability of finding cutinase homologs in various environmental resources that can be further explored for PET degradation.

On Tautomerism and Amphoterism: An In-Depth Structural and Physicochemical Characterization of Ammeline and Some of Its Salts.

Ammeline is a simple, readily available, molecular compound, which has been known for nearly 200 years. Despite that, no proper structural characterization of ammeline has been conducted so far. For this reason, the prevalent tautomeric form of ammeline in the solid remained unknown to this date. In the course of this study, its crystal structure was finally established by single-crystal X-ray diffraction. In this structure, ammeline is exclusively found as its 4,6‑diamino-1,3,5-triazin-2(1H)-one tautomer and adopts layered structure with an exceptionally high hydrogen bond density. Ammeline shows an interesting amphoteric behavior. Therefore, the synthesis and structural characterization of some of its salts were carried out to investigate the influence of the protonation degree on its molecular structure. In particular, the crystal structure of silver ammelinate monohydrate was solved as the first reported structure containing deprotonated ammeline. Moreover, the crystal structures of three different modifications of ammelinium perchlorate were elucidated and the transformation conditions between them were studied. Lastly, the crystal structure of ammelinediium diperchlorate monohydrate, containing unprecedented doubly protonated ammeline, was determined. The products' thermal behavior was studied by differential thermal analysis and thermogravimetric analysis. The perchlorate salts were additionally examined for their potential as insensitive high-energy-density materials.

On Tautomerism and Amphoterism: An In‐Depth Structural and Physicochemical Characterization of Ammeline and Some of Its Salts

Ammeline is a simple, readily available, molecular compound, which has been known for nearly 200 years. Despite that, no proper structural characterization of ammeline has been conducted so far. For this reason, the prevalent tautomeric form of ammeline in the solid remained unknown to this date. In the course of this study, its crystal structure was finally established by single‐crystal X‐ray diffraction. In this structure, ammeline is exclusively found as its 4,6‑diamino‐1,3,5‐triazin‐2(1H)‐one tautomer and adopts layered structure with an exceptionally high hydrogen bond density. Ammeline shows an interesting amphoteric behavior. Therefore, the synthesis and structural characterization of some of its salts were carried out to investigate the influence of the protonation degree on its molecular structure. In particular, the crystal structure of silver ammelinate monohydrate was solved as the first reported structure containing deprotonated ammeline. Moreover, the crystal structures of three different modifications of ammelinium perchlorate were elucidated and the transformation conditions between them were studied. Lastly, the crystal structure of ammelinediium diperchlorate monohydrate, containing unprecedented doubly protonated ammeline, was determined. The products’ thermal behavior was studied by differential thermal analysis and thermogravimetric analysis. The perchlorate salts were additionally examined for their potential as insensitive high‐energy‐density materials.

Long-Term Straw Incorporation under Controlled Irrigation Improves Soil Quality of Paddy Field and Rice Yield in Northeast China.

Soil quality is an indicator of the ability to ensure ecological security and sustainable soil usage. The effects of long-term straw incorporation and different irrigation regimes on the yield and soil quality of paddy fields in cold regions remain unclear. This study established four treatments: controlled irrigation + continuous straw incorporation for 3 years (C3), controlled irrigation + continuous straw incorporation for 7 years (C7), flooded irrigation + continuous straw incorporation for 3 years (F3), and flooded irrigation + continuous straw incorporation for 7 years (F7). Analysis was conducted on the impact of various irrigation regimes and straw incorporation years on the physicochemical characteristics and quality of the soil. The soil quality index (SQI) for rice fields was computed using separate datasets for each treatment. The soil nitrate nitrogen, available phosphorus, soil organic carbon, and soil organic matter contents of the C7 were 93.51%, 5.80%, 8.90%, and 8.26% higher compared to C3, respectively. In addition, the yield of the C7 treatment was 5.18%, 4.89%, and 10.32% higher than those of F3, C3, and F7, respectively. The validity of the minimum data set (MDS) was verified by correlation, Ef and ER, which indicated that the MDS of all treatments were able to provide a valid evaluation of soil quality. The MDS based SQI of C7 was 11.05%, 11.97%, and 27.71% higher than that of F3, C3, and F7, respectively. Overall, long-term straw incorporation combined with controlled irrigation increases yield and soil quality in paddy fields in cold regions. This study provides a thorough assessment of soil quality concerning irrigation regimes and straw incorporation years to preserve food security and the sustainability of agricultural output. Additionally, it offers a basis for soil quality diagnosis of paddy fields in the Northeast China.

Targeted Anthocyanin Enrichment of Cranberry Juice by Electrodialysis with Filtration Membranes: Impact of Filtration Membrane Physicochemical Properties and Predictive Statistical Models.

To optimize cranberry juice enrichment, correlation between physicochemical properties of filtration membranes (FM) and anthocyanin migration was investigated during electrodialysis with filtration membranes (EDFM) using redundancy (RDA) and multivariate regression (MRGA) analyses. Six polyether sulfone (PES) and polyvinylidene fluoride (PVDF) membranes with molecular weight cut-offs between 150 and 500 kDa, commercially available at large scale, were characterized in terms of nine physicochemical characteristics and used for EDFM. The highest migration of total anthocyanin was obtained with PVDF 250 kDa, with a global migration rate of 3.5 ± 0.4 g/m2·h. RDA showed that two FM properties (mesopore porosity and hydrophilic porosity) were significantly negatively correlated to the anthocyanin's migration and explained 67.4% of their total variation in migration. Predictive MRGA models were also developed for each anthocyanin based on these significant FM properties. A combination of intermolecular interactions may lead to binding in a cooperative and synergistic mode and hinder the anthocyanin migration.

Physicochemical Characterization, Antioxidant and Tyrosinase Inhibitory Activities of Coffea Robusta Monofloral Honey from Dak Lak Province, Vietnam.

Robusta coffee blossom honey stands as a key regional product in Dak Lak province, Vietnam. Despite its significance, there exists a dearth of scientific data for assessing its quality. This study aims to fill this gap by characterizing the physicochemical properties and biological activities of coffee blossom honeys from three distinct sub-regions within Dak Lak province, Vietnam. These activities include ferric reducing power (FRP), DPPH and ABTS radical scavenging, as well as tyrosinase inhibitory activities. Moreover, the study compares these honey samples with other popular varieties in Vietnam, such as Lychee and Longan honeys. The physicochemical parameters of the honey samples meet the standards set by Codex Alimentarius 2001. Through UPLC analysis, eleven compounds were identified, with caffeine serving as a marker for coffee honey. Furthermore, by employing multiple factor analysis (MFA), it was observed that certain physicochemical properties correlate positively with tyrosinase inhibitory, DPPH, ABTS free radicals scavenging activities, and FRP. Notably, tyrosinase inhibitory activity exhibited a positive correlation with antioxidant activity. These findings underscore the high quality of Coffea robusta honey, showcasing its potent antioxidant and tyrosinase inhibitory activities.

Spondias tuberosa and Spondias mombin: Nutritional Composition, Bioactive Compounds, Biological Activity and Technological Applications

The genus Spondias has two species of native trees from Brazil that deserve to be highlighted: Spondias tuberosa (“umbu”) and Spondias mombin (“cajá”). Their fruit contain bioactive compounds which have been associated with several biological activities. However, they remain little exploited in the development of food and pharmaceutical products. In this perspective, the present review summarizes the literature data about the physicochemical and nutritional characteristics, bioactive compounds, potential health benefits, and industrial applications of these fruit, including their pulp, seed, and peel. The current scenery mapping for scientific articles was performed in the Scopus and Web of Science databases. The study also considered patent applications collected in the Derwent database. Results showed an increase in scientific publications in recent years for both species. Many applications are related to food technology; nevertheless, due to the composition of their non-edible fractions, they have the potential for use in biorefinery, being their use an opportunity for bioeconomy. Thus, this review provides a comprehensive overview of these Brazilian native fruit to offer a theoretical foundation and valuable data for future investigations and exploitation.

Potatoes (Solanum tuberosum L.) grown at “Patata dell'alto Viterbese” PGI have different quality characteristics and storage responses

Four pre-selected potato cultivars (Solanum tuberosum L.) from the “Patata dell’Alto Viterbese” PGI area underwent physico-chemical and enzymatic characterization to assess their suitability for specific processing line. Key chemical parameters (reducing sugar content (RSC), total phenol content (TPC), dry matter (DM), physical attributes (firmness), physico-chemical aspects (color, browning development), and enzymatic factors (polyphenol oxidase enzyme activity, PPO) were analyzed at harvest and monthly during a 6-month storage period over two production seasons (2020 and 2021). The results of one-way within-subject ANOVA and Principal Component Analysis (PCA) highlighted the superior attributes of the ‘Fontane’ cultivar for the processing industry, particularly for frying applications (e.g., chips, French fries, etc.). In comparison to other tested cultivars, ‘Fontane’ exhibited: i) the highest DM (> 200 g kg−1), ii) the lowest TPC and RSC, iii) the greatest firmness, iv) low susceptibility to browning, and v) high tolerance to Low-Temperature Sweetening (LTS). The ‘Jelly’ cultivar displayed favorable attributes for versatile use, suitable for both fresh market uses (roasting, homemade “gnocchi”, etc.) and industrial applications (fresh-cut or dried potato). It demonstrated high DM content (200 g kg−1) and firmness, the lowest PPO activity, good TPC, but higher RSC than ‘Fontane’. However, elevated RSC for ‘Jelly’ renders it less suitable for industrial frying. ‘Constance’ and ‘Gaudi’ exhibited positive traits for fresh market use such as boiling and steaming, with moderate to low DM content and firmness. Nonetheless, both cultivars displayed low tolerance to LTS, and ‘Gaudi’ exhibited the poorest processing properties, showing the highest susceptibility to browning.

Inactivation of Salmonella Typhimurium, Escherichia coli, and Staphylococcus aureus in Tilapia Fillets (Oreochromis niloticus) with Lactic and Peracetic Acid through Fogging and Immersion.

This study investigated the antimicrobial effects of lactic acid (LA) (3%) and peracetic acid (PA) (300 ppm) on tilapia fillets (Oreochromis niloticus) by fogging (15 min) or by immersion (2 s) in a pool of Escherichia coli (NEWP 0022, ATCC 25922, and a field-isolated strain), Staphylococcus aureus (ATCC 25923 and a field-isolated strain), and Salmonella Typhimurium (ATCC 13311 and ATCC 14028), as well as the effects on the physicochemical characteristics of the fillets. Fogging was effective and the best application method to control S. Typhimurium regardless of the acid used, promoting reductions of 1.66 and 1.23 log CFU/g with PA and LA, respectively. Regarding E. coli, there were significant reductions higher than 1 log CFU/g, regardless of the treatment or acid used. For S. aureus, only immersion in PA showed no significant difference (p < 0.05). For other treatments, significant reductions of 0.98, 1.51, and 1.17 log CFU/g were observed for nebulized PA, immersion, and LA fogging, respectively. Concerning the pH of the samples, neither of the acids used differed from the control. However, treatments with LA, and fogging with PA, reduced the pH compared to immersion in PA. As for color parameters, L* and a* values showed changes regardless of the acid or method used, resulting in an improved perception of fillet quality. These results indicate that fogging and immersion are alternatives for reducing S. Typhimurium, E. coli, and S. aureus in tilapia fillets.

Polymer‐Protected Gold Nanoparticles for Photothermal Treatment of Ehrlich Adenocarcinoma: In Vitro and In Vivo Studies

AbstractPhotothermal therapy (PTT) is recognized as an effective tool for the treatment of cancer and it has attracted considerable attention of scientists. In this work, gold nanospheres (AuNSs) and gold nanorods (AuNRs) stabilized using poly(N‐vinylpyrrolidone) (PVP), pristine gellan gum (PGG), and poly(2‐ethyl‐2‐oxazoline)‐grafted gellan gum (GG‐g‐PEtOx) are synthesized and evaluated as PTT agents in Ehrlich cancer cells. The physicochemical characteristics of these AuNSs and AuNRs, including their surface plasmon resonance absorption spectra, size, zeta potential, and aspect ratio are studied using UV–vis‐spectroscopy, dynamic light scattering, zeta potential, transmission electron microscopy, and optical microscopy techniques. The polymer‐protected AuNSs exhibit light‐to‐heat conversion, raising the temperature from 37 to 43 °C when irradiated using a visible light source. In the case of AuNSs, considerable damage to Ehrlich cancer cells is observed following irradiation and 40 days of examination. However, with regard to AuNSs, the damage to Ehrlich cancer cells is slightly lower than observed in AuNRs. In vivo experiments demonstrate that laser irradiation of tumors in mice after injecting AuNSs leads to a statistically significant decrease in tumor size as compared to those not irradiated and the control samples.

Dynamic Monitoring of Biomolecular Hydrodynamic Dimensions by Magnetization Motion on Quartz Crystal Microbalance.

Hydrodynamic dimension (HD) is the primary indicator of the size of bioconjugated particles and biomolecules. It is an important parameter in the study of solid-liquid two-phase dynamics. HD dynamic monitoring is crucial for precise and customized medical research as it enables the investigation of the continuous changes in the physicochemical characteristics of biomolecules in response to external stimuli. However, current HD measurements based on Brownian motion, such as dynamic light scattering (DLS), are inadequate for meeting the polydisperse sample demands of dynamic monitoring. In this paper, we propose MMQCM method samples of various types and HD dynamic monitoring. An alternating magnetic field of frequency ωm excites biomolecule-magnetic bead particles (bioMBs) to generate magnetization motion, and the quartz crystal microbalance (QCM) senses this motion to provide HD dynamic monitoring. Specifically, the magnetization motion is modulated onto the thickness-shear oscillation of the QCM at the frequency ωq. By analysis of the frequency spectrum of the QCM output signal, the ratio of the magnitudes of the real and imaginary parts of the components at frequency ωq ± 2ωm is extracted to characterize the particle size. Using the MMQCM approach, we successfully evaluated the size of bioMBs with different biomolecule concentrations. The 30 min HD dynamic monitoring was implemented. An increase of ∼10 nm in size was observed upon biomolecular structural stretching. Subsequently, the size of bioMBs gradually reduced due to the continuous dissociation of biomolecules, with a total reduction of 20∼40 nm. This HD dynamic monitoring demonstrates that the release of biomolecules can be regulated by controlling the duration of magnetic stimulation, providing valuable insights and guidance for controlled drug release in personalized precision medicine.

Genome wide analysis of carotenoid cleavage oxygenases (CCO) gene family in Arachis hypogaea (peanut) under biotic stress

Carotenoid cleavage oxygenases (CCOs) enzymes play a vital role in plant growth and development through the synthesis of apocarotenoids and their derivative. These chemicals are necessary for flower and fruit coloration, as well as the manufacture of plant hormones such as abscisic acid (ABA) and strigolactones, which control a variety of physiological processes. The CCOs gene family has not been characterized in Arachis hypogaea. Genome mining of A. hypogaea identifies 24 AhCCO gene members. The AhCCO gene family was divided into two subgroups based on the recent study of the Arabidopsis thaliana CCO gene family classification system. Twenty-three AhCCO genes, constituting 95.8% of the total, were regulated by 29 miRNAs, underscoring the significance of microRNAs (miRNAs) in governing gene expression in peanuts. AhCCD19 is the only gene that lacks a miRNA target site. The physicochemical characteristics of CCO genes and their molecular weights and isoelectric points were studied further. The genes were then characterized regarding chromosomal distribution, structure, and promoter cis-elements. Light, stress development, drought stress, and hormone responsiveness were discovered to be associated with AhCCO genes, which can be utilized in developing more resilient crops. The investigation also showed the cellular location of the encoded proteins and discovered that the peanut carotenoid oxygenase gene family’s expansion was most likely the result of tandem, segmental, and whole-genome duplication events. The localization expresses the abundance of genes mostly in the cytoplasm and chloroplast. Expression analysis shows that AhCCD7 and AhCCD14 genes show the maximum expression in the apical meristem, lateral leaf, and pentafoliate leaf development, while AhNCED9 and AhNCED13 express in response to Aspergillus flavus resistance. This knowledge throws light on the evolutionary history of the AhCCO gene family and may help researchers better understand the molecular processes behind gene duplication occurrences in plants. An integrated synteny study was used to find orthologous carotenoid oxygenase genes in A. hypogaea, whereas Arabidopsis thaliana and Beta vulgaris were used as references for the functional characterization of peanut CCO genes. These studies provide a foundation for future research on the regulation and functions of this gene family. This information provides valuable insights into the genetic regulation of AhCCO genes. This technology could create molecular markers for breeding programs to develop new peanut lines.

Nanoemulsion‐laden poly(vinyl) alcohol hydrogel films for transdermal delivery of carbamazepine

AbstractThere is an unmet demand for transdermal devices that can deliver large dose of medications through the skin. Herein, nanoemulsion‐based poly(vinyl alcohol) (PVA) transdermal hydrogel films were developed for the high‐dose anti‐epileptic drug carbamazepine. A stable nanoemulsion was created with almond oil, Tween 60, and amphiphilic locust bean gum. The nanoemulsion had a hydrodynamic diameter of 251 nm, a polydispersity of 10.3%, and a zeta potential of −51.2 mV. Carbamazepine‐loaded nanoemulsion was blended with carbamazepine‐free PVA dispersion and casted into films. To accommodate a high dose, carbamazepine‐loaded nanoemulsion was trapped in a PVA dispersion containing carbamazepine to create transdermal films. The physicochemical characteristics and drug penetration characteristics of the produced films were compared. Both films had the uniform thickness, weight, and drug content. The folding endurance was found to be greater than 700 in both cases. Water vapor permeability decreased when carbamazepine was added to almond oil as well as polymer dispersion. FESEM pictures revealed a waxy paper‐like appearance for the PVA hydrogel film with dual drug‐reservoirs. FTIR spectra assessment revealed a hydrogen bonding interaction between PVA and carbamazepine. X‐ray diffraction examination revealed that the film contained an amorphous dispersion of carbamazepine. Dual carbamazepine reservoir‐based films outperformed single nanoemulsion drug reservoir‐based films in terms of drug flux through excised rat skin by 3.2 times. The in vitro skin permeation findings corresponded well to zero order kinetic models. Overall, this study showed that a high‐dose drug could be placed on nanoemulsion‐based transdermal PVA hydrogel films, resulting in improved skin permeability.Highlights Nanoemulsion was stable at almond oil:Tween 60/modified gum ratio of 5:5. Loading of high dose carbamazepine in nanoemulsion‐PVA transdermal films. Film of dual carbamazepine reservoir showed low water vapor permeation, moisture retention. Flux of carbamazepine from films improved three times through excised rat skin.

3D-printed short nanofibers/hydrogel-based vaginal films as a novel system for the delivery of anti-HIV microbicide drugs

Acquired immunodeficiency syndrome (AIDS) is a global epidemic that affects the lives of millions of young women, particularly those who live in poverty-stricken regions and engage in unsafe sexual behaviors, forcing the development of unique pre-exposure anti-HIV prophylaxis tools. Using a combination of antiretroviral medications with various antiviral mechanisms significantly improves the prognosis for HIV patients. The integration of 3D printing technology, short nanofiber technology, and hydrogel into a single system known as “3D-printed nanocomposites” is an emerging approach that is gaining traction in tissue engineering, regenerative medicine, and biomedical applications. Based on these foundations, the current study aims to develop, for the first time, a 3D-printed short nanofiber/film for the vaginal delivery of ritonavir and efavirenz in a fixed-dose combination. To identify an optimal 3D-printable short nanofibers/hydrogel formulation, multiple formulations, and fragmentation methods were investigated. Following that, the generated vaginal films were evaluated using several physicochemical characterizations, mechanical properties measurements, and in vitro release studies. The findings revealed that only cryocutting is effective for polycaprolactone nanofiber fragmentation. The 3D-printed short nanofibers-loaded films had an ultimate tensile strength of 6.75 ± 1.27 MPa and elongation at break of 262.67 ± 44.32 MPa, suggesting their reliability for handling and vaginal application. Furthermore, the in vitro release study demonstrated that rapid EFZ release occurred during the first 45 min, whereas RIT release lasted more than 72 h, indicating that the complex drug release profile was met. In summary, the study emphasizes that 3D printing of short nanofiber-based films is likely to be an effective platform for localized vaginal drug delivery, particularly anti-HIV therapies.

A Phosphine-Oxide Cobalt(II) Complex and Its Catalytic Activity Studies toward Alcohol Dehydrogenation Triggered Direct Synthesis of Imines and Quinolines.

Herein, a new pincer-like amino phosphine donor ligand, H2L1, and its phosphine-oxide analog, H2L2, were synthesized. Subsequently, cobalt(II) complexes 1 and 2 were synthesized by the reaction of anhydrous Co(II)Cl2 with ligands H2L1 and H2L2, respectively. The ligands and complexes were fully characterized by various physicochemical and spectroscopic characterization techniques. Finally, the identity of the complexes 1 and 2 was confirmed by single crystal X-ray structure determination. The phosphine ligand containing complex 1 was converted to the phosphine oxide ligand containing complex 2 in air in acetonitrile solution. Both complexes 1 and 2 were investigated as precatalysts for alcohol dehydrogenation-triggered synthesis of imines in air. The phosphine-oxide complex 2 was more efficient than the phosphine complex 1. A wide array of alcohols and amines were successfully reacted in a mild condition to result in imines in good to excellent yields. Precatalyst 2 was also highly efficient for the synthesis of varieties of quinolines in air. As H2L2 in 2 has side arms that can be deprotonated, we investigated complex 2 for its base (KOtBu) promoted deprotonation events by various spectroscopic studies and DFT calculations. These studies have shown that mono deprotonation of the amine side arm attached to the pyridine is quite feasible, and deprotonation of complex 2 leads to a dearomatized pyridyl ring containing complex 2a. The mechanistic investigations of the catalytic reaction, by a combination of experimental and computational studies, have suggested that the dearomatized complex, 2a acted as an active catalyst. The reaction proceeded through the hydride transfer pathway. The activation barrier of this step was calculated to be 26.5 kcal/mol, which is quite consistent with the experimental reaction temperature under aerobic conditions. Although various pincer-like complexes are explored for such reactions, phosphine oxide ligand-containing complexes are still unexplored.

Water Quality and Environmental Health of Lakes in Coimbatore, India: A Comprehensive Study of the Physicochemical Characteristics

The deterioration of lake water quality is a major national issue, particularly in regions with industrial activity. This study assesses the water quality of five lakes in Coimbatore, India: Krishnampathi, Ukkadam, Kurichi, Sulur, and Singanallur, between December 2016 and April 2017. Twenty physicochemical parameters were analysed following standard procedures outlined by the American Public Health Association. Twelve heavy metal elements concentration in the lakes was analysed using inductively coupled plasma-mass spectroscopy. The results of this study revealed that the values of 17 physicochemical parameters fell beyond the WHO recommended pollution levels in all the study sites, except Sodium, Nitrate, and Sulphate. While, the concentration of 10 heavy metal elements determined were within acceptable limits of WHO-recommended standards for drinking water across all lakes, except Fe and Pb. F-test revealed that the concentration of all the physicochemical parameters varied significantly across all the study sites, except for pH (P = .749). Statistical analysis such as principal component analysis was adopted, and the results were discussed on the multivariate relationships of the physiochemical parameters and heavy metal concentrations of the five study sites. Overall, the findings highlight the urgent need for continuous monitoring and comprehensive management strategies to mitigate the deteriorating water quality in the lakes of Coimbatore district, emphasizing the critical importance of addressing the multitude of factors contributing to this environmental challenge.

Physico-chemical and correlation study of ground drinking water of Tonk district of Rajasthan (India)

This study investigates the qualitative analysis of groundwater obtained from the Tonk district of Rajasthan to determine its suitability as potable water. Around 321 ground drinking water samples were collected and analysed for various physico-chemical characteristics including pH, electrical conductivity (EC), total dissolved solid (TDS), HCO3−, F−, Cl−, SO42−, NO3−, Ca2+, Mg2+, total hardness (TH) and total alkalinity (TA) in Tonk district of Rajasthan (India). The groundwater in the region is a little alkaline and hard. The EC during the pre-monsoon period varies from 434 to 7271 µS/cm, while in the post-monsoon period, it ranges from 356 to 8871 µS/cm. TDS of samples ranged between 285 to 5090 mg/L in the pre-monsoon and 247 to 6140 mg/L post-monsoon seasons. Few samples have EC, TDS, and TH levels higher than the permissible limit, restricts its usage as drinking water. The water quality in the study area varies from soft-fresh to hard-brackish in both pre- and post-monsoon seasons. Anion concentrations in analysed samples followed the order: HCO3− > Cl− > SO42− > NO3− > F−. Notably, the Water quality index (WQI) results for all collected samples fall within the range of 4.55–96.83, indicating they are considered safe and suitable for drinking purposes. Water quality data was analysed by correlation study and geochemical processes. A strong correlation between the Water Quality Index (WQI) and fluoride levels is found in both seasons. The geochemical analysis shows that most of the samples are in the rock water interaction zone, with some in the evaporation zone due to the high content of chloride ions. The groundwater chemistry appears to be influenced by rock-water interaction and evaporation sedimentation. The molar ratio of Ca2+/Mg2+ denotes calcite dissolution and silicate weathering revealing enrichment of Ca2+ and HCO3− ions in aquifer.