Aqueous Ones Research Articles

An Evaluation of Antimicrobial Activity of Common Zingiber officinale Cultivars Grown in Sri Lanka

Ginger (Zingiber officinale) has long been a therapeutic agent in traditional medicine systems worldwide and is a leading drug candidate in the pharmaceutical industry. In Sri Lanka, many forms of ginger are often used in the food industry, mainly as a spice; it also plays a vital role in the Ayurvedic medicine system. This study evaluated the antimicrobial activity of the two most cultivated cultivars of Zingiber officinale in Sri Lanka, the Sri Lankan (TG) and Chinese (CG) cultivars. Two types of extracts (ethanol and aqueous) were obtained from the rhizomes of each cultivar. The potential antimicrobial activity of the extracts was tested against three types of pathogenic test organisms, Staphylococcus aureus ATCC 25923, Salmonella typhi DSM 17058, and Escherichia coli ATCC 25922, using the agar well diffusion method along with positive control, chloramphenicol, and negative controls, 95% ethanol or distilled water. In conclusion, both Zingiber officinale cultivars exhibit varying antimicrobial potential, with ethanol extracts showing stronger activity than aqueous ones. None of the extracts was effective against Escherichia coli. The agar dilution method determined the minimum inhibitory concentration (MIC) of each ginger extract. Among the extracts, ethanol extracts showed higher effectivity than aqueous extracts, where all test organisms showed inhibition at a concentration of 20 mg/mL. The antimicrobial activity of the Chinese cultivar outperforms the Sri Lankan cultivar against target organisms, Salmonella typhi, and Staphylococcus aureus.

Cathode Electrolyte Interphase Engineering for Prussian Blue Analogues in Lithium-Ion Batteries.

The increasing use of low-cost lithium iron phosphate cathodes in low-end electric vehicles has sparked interest in Prussian blue analogues (PBAs) for lithium-ion batteries. A major challenge with iron hexacyanoferrate (FeHCFe), particularly in lithium-ion systems, is its slow kinetics in organic electrolytes and valence state inactivation in aqueous ones. We have addressed these issues by developing a polymeric cathode electrolyte interphase (CEI) layer through a ring-opening reaction of ethylene carbonate triggered by OH- radicals from structural water. This facile approach considerably mitigates the sluggish electrochemical kinetics typically observed in organic electrolytes. As a result, FeHCFe has achieved a specific capacity of 125 mAh g-1 with a stable lifetime over 500 cycles, thanks to the effective activation of Fe low-spin states and the structural integrity of the CEI layers. These advancements shed light on the potential of PBAs to be viable, durable, and efficient cathode materials for commercial use.

Formation of natural fractures and their impact on shale oil accumulation in the Mahu Sag, Junggar Basin, NW China

Lacustrine shale oil reservoirs of the Fengcheng Formation in the Mahu Sag, Junggar Bain, NW China contain abundant oil resources, with the highest daily oil production of a single well reaching over 700 barrels. Based on core and thin section observation along with borehole image interpretation, this study integrated paleotectonic stress regime, fluid inclusion analysis, and calcite UPb dating to clarify fracturing periods and discuss the influence of fractures on shale oil accumulation. Results show that natural opening-mode fractures are widespread in the Fengcheng Formation, which play an important role in oil accumulation. Fractures are developed in several stages and filled by three minerals: reedmergnerite, quartz and calcite. Reedmergnerite and quartz fillings show similar fluid inclusions and petrographic features, with numerous hydrocarbon inclusions compared to aqueous ones, yet, such inclusions were less observed in calcite fillings. Fractures in the study area were formed in two separate stages. In the first period, due to the NW-SE compression of the Hercynian movement, the WNW-ESE and NNW-SSE striking fractures were formed in the Late Permian, with Th values of 95–115 °C. The first stage of fractures coincided with hydrocarbon generation, providing migration pathways for the oil. In the second period, due to the nearly SN compression of the Indosinian movement, the NNW-SSE and NNE-SSW striking fractures were formed in the late Triassic, with Th values of 120–140 °C. The second stage of fractures was formed subsequent to major hydrocarbon generation and expulsion period, hence their contribution to hydrocarbon migration and accumulation was found relatively minor. Moreover, fractures with the nearly E-W, ENE-WSW and WNW-ESE strikes intersect with the present-day maximum horizontal principal stress at a small angle, with large apertures and good connectivity, which should have a positive impact on shale oil accumulation.

Prophylactic effects of dietary caper (Capparis spinosa) extracts on the control of Streptococcus agalactiae infection, growth, immune-antioxidant, and inflammation cytokine responses of Nile tilapia fingerlings

The antibacterial activity of aqueous (AE) or ethanolic extracts (EE) of caper (Capparis spinosa) against Streptococcus agalactiae was evaluated in vitro. Both caper extracts showed antagonistic activity against S. agalactiae and the inhibition zones in case of ethanolic extracts were larger than those of aqueous ones. Additionally, TEM investigations show that S. agalactiae cells treated with both C. spinosa extracts were damaged and degraded and this damage was greater in case of ethanolic extract. Another study was done to assess the promotion effects of dietary caper (C. spinosa) extracts on growth, antioxidant and immune activity, and inflammation cytokine responses of Nile tilapia (Oreochromis niloticus) and its resistance to S. agalactiae infection. However, fish (40 ± 2 g) were fed on diets containing 1.0 and 2.0 g/kg feed of each caper extract as well as the control group (free of caper) for 6 weeks. Fish were intraperitoneally injected (IP) with Streptococcus agalactiae at the end of the feeding trial, and fish mortality was tracked for additional ten days. Compared with other treatments, fish fed on 2.0 g EE/kg feed had higher counts of white and red blood cells as well as higher hemoglobin levels accompanied with lower AST and ALT activities. Antioxidant (superoxide dismutase and catalase activities) and immune, total protein, globulin, lysozyme, and immunoglobulin M) indices were increased along with significant decline in MDA levels in both caper extracts treated fish groups compared to the control group. Significant promotion in fish growth was affected positively with the increase in both caper extracts; particularly, the larger fish growth was observed in the treatment of 2.0 g EE/kg feed. Expressions of IL-1β and IL-8 were declined; meanwhile levels of IL-10, SOD and CAT genes were upregulated in fish fed on 2.0 g EE/kg feed compared to other groups. After being challenged with S. agalactiae infection, fish survival was considerably (P < 0.05) greater in fish groups that fed on diets with caper extracts; particularly 2.0 g EE/kg feed (75%); while all fish fed on the control one were dead. According to these findings, the antioxidant and immune response of Nile tilapia fingerlings is stimulated by ethanolic extract of caper (2.0 g/kg feed), which also enhanced the growth performance and fish resistance to S. agalactiae infection.

Antibacterial activity of Gardenia jasminoides Ellis leaves extracts on bacteria isolated from burns infected

This study provides scientific information about the aqueous and methanol extracts of Gardenia jasminoides Ellis leaves based on its antimicrobial potential against gram positive and gram negative bacteria isolated From burns infection using the broth dilution and disc diffusion method. Results of this study indicate the presence of many phytochemicals which have antimicrobial activity against broad spectrum of bacteria.The methanol extract of G. jasminoides showed highest activity than aqueous ones . The minimum inhibitory concentration (MIC)of the aqueous extract on the tested organisms was25_100mg/ml while in the methanol extract ranged between 25_50mg/ml on the tested organisms and the minimum bacterial concentration (MBC) of the aqueous extract was 25-200 mg/ml while the methanol extract ranged between 25-100 mg/ml. Essential element (Pb, Na, K, Ca, Fe, Zn, P, Mn, Co and Cu) at different concentration. The result of this study demonstrate that G.jasminoides constituent revealed that this plant have antimicrobial activity against test organism and this may be suggest the use at this extract in treatment of infectious disease

Thermo-Mechanical Fluid-Structure Interaction Numerical Modelling and Experimental Validation of MEMS Electrothermal Actuators for Aqueous Biomedical Applications.

Recent developments in MEMS technologies have made such devices attractive for use in applications that involve precision engineering and scalability. In the biomedical industry, MEMS devices have gained popularity in recent years for use as single-cell manipulation and characterisation tools. A niche application is the mechanical characterisation of single human red blood cells, which may exhibit certain pathological conditions that impart biomarkers of quantifiable magnitude that are potentially detectable via MEMS devices. Such applications come with stringent thermal and structural specifications wherein the potential device candidates must be able to function with no exceptions. This work presents a state-of-the-art numerical modelling methodology that is capable of accurately predicting MEMS device performance in various media, including aqueous ones. The method is strongly coupled in nature, whereby thermal as well as structural degrees of freedom are transferred to and from finite element and finite volume solvers at every iteration. This method therefore provides MEMS design engineers with a reliable tool that can be used in design and development stages and helps to avoid total reliability on experimental testing. The proposed numerical model is validated via a series of physical experiments. Four MEMS electrothermal actuators with cascaded V-shaped drivers are presented. With the use of the newly proposed numerical model as well as the experimental testing, the MEMS devices' suitability for biomedical applications is confirmed.

Isolation of Biologically Active Compounds from Cannabis sativa L. Inflorescences by Using Different Extraction Solvents and Evaluation of Antimicrobial Activity.

Hemp inflorescences are a source of vital compounds, including phytocannabinoids and other biologically active compounds. Various methods are adapted for the extraction of these vital compounds such as the use of different organic solvents. This study aimed to assess the comparative extraction potential of three different solvents: deionized water, 70% methanol (MeOH), and 2% Triton X-100, for phytochemicals in hemp inflorescences. Spectrophotometric techniques were applied to investigate the total amount of polyphenolic compounds (TPC), total flavonoids contents (TF), phenolic acids (TPA), and radical scavenging activity (RSA) in hemp extracts obtained using different polarity solvents. Gas chromatography-mass spectrometry was used for cannabinoids and organic acids quantitative analysis. In the results, MeOH showed a better affinity for the recovery of TFC, TPA, and RSA in comparison to Triton X-100 and water. However, Triton X-100 performed better for TPC with 4-folds and 33% turnover compared to water and MeOH, respectively. Six cannabinoids (CBDVA, CBL, CBD, CBC, CBN, and CBG) were identified in hemp inflorescence extracts. The maximum determined concentration was as follows: CBD > CBC > CBG > CBDVA > CBL > CBN. Overall, fourteen organic acids were identified. Hemp inflorescence extracts obtained using 2% Triton X-100 showed an effect on all tested strains of microorganisms. Methanolic and aqueous extracts had antimicrobial activity against seven tested strains. On the other hand, the inhibition zones were wider for methanolic extracts compared to aqueous ones. Hemp aqua extract with antimicrobial activity might be used in various markets where toxic solvents are unwanted.

Withania somnifera L.: Phenolic Compounds Composition and Biological Activity of Commercial Samples and Its Aqueous and Hydromethanolic Extracts.

In the present study, the chemical composition and bioactive properties of commercially available Withania somnifera samples were evaluated. The hydromethanolic and aqueous extracts of the tested samples were analyzed in terms of phenolic compound composition, ascorbic acid content, antioxidant and antibacterial activity, and acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. Polyphenols and ascorbic acid content, as well as the antioxidant activity, were higher in the aqueous extracts than in the hydromethanolic extracts. Generally, aqueous extracts presented higher antioxidant activity than the hydromethanolic ones, especially in the case of 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay. Moreover, higher amounts of phenolic acids and flavonoids were found in the hydromethanolic extracts compared to the aqueous ones. Regarding the antibacterial properties, samples 4, 6, and 10 showed the best overall performance with growth-inhibitory activities against all the examined bacteria strains. Finally, the aqueous and hydromethanolic extracts were the most efficient extracts in terms of AChE and BChE inhibitory activities, respectively. In conclusion, our results indicate that W. somnifera possesses important bioactive properties which could be attributed to the high amounts of phenolic compounds. However, a great variability was recorded in commercially available products, suggesting significant differences in the origin of product and the processing method.

Volatile and Non-Volatile Content Determination and Biological Activity Evaluation of Fresh Humulus lupulus L. (cv. Chinook) Leaves and Inflorescences

In this work, the fresh leaves and inflorescences of Humulus lupulus L. cv. Chinook hops were investigated in order to describe their chemical composition and evaluate their biological activities. The analyses were carried out first on fresh untreated samples and then on pulverized ones using the SPME-GC-MS technique. In total, forty-two molecules belonging to different chemical classes were identified, and among these, twenty-three were terpene compounds. In order to carry out the activity assays, the powders were subjected to extraction with two different solvents (methanol and distilled water) by stirring and subsequent sonication at room temperature. To chemically characterize the extracts, the methanolic ones were analyzed by direct injection into the GC-MS apparatus, while the aqueous ones were analyzed by DI-SPME-GC-MS. In addition, with the aim to obtain information on the non-volatile content of the methanolic extracts, they were also subjected to derivatization, and the silylated derivatives were analyzed by GC-MS. The antioxidant activity was then evaluated by means of DPPH and ABTS assays after the determination of the total content of polyphenols and flavonoids. The greatest effects were observed on the methanolic extracts rather than on the aqueous ones. Furthermore, a preliminary study on the cytotoxic power of the methanolic extracts was also conducted on three different human cancer cell lines, such as non-small cell lung cancer (H1299), melanoma (A375) and breast cancer (MCF7). The obtained results showed that the two extracts induced a marginal effect on reducing breast tumor, melanoma and non-small cell lung cancer cell proliferation.

Chaga mushroom triterpenoids as adjuncts to minimally invasive cancer therapies: A review

Cancer has become the second leading cause of death in the world. Integrative cancer therapy management is continuously evolving to enhance treatment outcomes. Chaga mushroom (Inonotus obliquus) is a parasitic fungus acclaimed to contain pharmaceutical and nutraceutical value in the fight against cancer. In particular, triterpenoid constituents derived from Chaga mushrooms have been recognized for their anti-cancer activity after distinguished cytotoxicity was repeatedly observed in cancer cells treated in vitro with lipophilic fractions of extract compared to aqueous ones. Studies that investigate the anti-cancer activity of Chaga mushroom triterpenoids are reviewed in this article to determine which cancer cell lines demonstrate the greatest susceptibility to them while highlighting the structure–activity relationships that are involved. Triterpenoid supplementation as an adjunct to cancer treatment may be a viable option as inotodiol and 3-β-22 α-dihydroxylanosta-8, 25-diene-24-one have been shown to exhibit anti-cancer activity similar to that of conventional drugs. Advances in addressing bioavailability challenges are also included in this review as studies include in vivo components.

Aqueous hybrid electrochemical capacitors with ultra-high energy density approaching for thousand-volts alternating current line filtering

Filtering capacitors with wide operating voltage range are essential for smoothing ripples in line-powered system, which are still unsatisfactory due to low energy density and limited working voltage scopes. Herein, we report an aqueous hybrid electrochemical capacitor with areal specific energy density of 1.29 mF V2 cm−2 at 120 Hz, greater than common aqueous ones. Interestingly, it can be easily integrated at scale to show excellent flexibility, controllable and stable filtering performance, in which an integrated device (e.g., seven units in series) exhibits fluctuation of 96 mV, 10 times smaller than an aluminum electrolytic capacitor with similar capacitance. A record-high 1,000 V can also be achieved after integrating 670 units, exceeding those reported so far, and about 1.5 times of commercial bulk aluminum electrolytic capacitors (~700 V). This work opens up a new insight for promising applications in multiple electricity transmission systems that requiring high smoothness under harsh voltage.

Anthelmintic Activity, Cytotoxicity, and Phytochemical Screening of Plants Used to Treat Digestive Parasitosis of Small Ruminants in Benin (West Africa).

Simple SummaryIn the present study, we explored the anthelmintic activity, cytotoxicity, and chemical composition of the main plants used by small ruminant breeders in Benin to treat digestive parasitosis. The results obtained are relevant in the sense that they will allow a rational use of the plants studied in the control of digestive parasites but also to initiate the process of identification of new anthelmintic molecules in the context of the development of resistance against the most currently used anthelmintic molecules.Medicinal plants continue to be used alone or in combination with veterinary drugs to treat animal ailments, especially in developing countries where livestock farmers often lack access to modern veterinary services and drugs. In addition, digestive parasitosis remain a major constraint for small ruminant livestock. The objective of this study was to screen the anthelmintic activity of the main plants used in the treatment of the digestive parasitosis of small ruminants in Benin. A total of 40 extracts were prepared using the successive maceration of 10 plants in four solvents of increasing polarity. The phytochemical screening of the plants was performed, and the anthelmintic activity of the extracts was evaluated on L3 larvae of Haemonchus contortus. The cytotoxicity of the 40 extracts was determined on WI38 noncancerous fibroblast cells using the MTT assay, and the total phenol content (TPC), total flavonoid content (TFC), and condensed tannin content (CTC) were quantified in the most effective extracts using colorimetric methods. The results show that the plants contained tannins, flavonoids, and triterpenoids which may, in part, justify their anthelmintic activities. All plants gave active extracts at the highest concentration tested (1200 µg/mL). Methanol (MeOH) extracts were, in general, more effective than the hexane (HEX), dichloromethane (DCM), and aqueous (H2O) ones in inhibiting larval migration, with the MeOH extracts of Terminalia leiocarpa, Adansonia digitata, and Momordica charantia being the most effective. Nevertheless, the MeOH extract of M. charantia was highly cytotoxic at the concentration of 100 µg/mL. The anthelmintic activity of M. charantia, Vitex doniana, and Caesalpinia bonduc was studied on H. contortus for the first time. These results provide scientific information that can be used for better valorization of the anthelmintic potential of the studied plants and to initiate the process of the identification of new anthelmintic molecules.

Global model of plasma‐activated water over long time scale: Pulsed discharge and afterglow

AbstractPlasma‐activated water (PAW) has been utilised in various application fields, and a deep understanding on the plasma chemistry is the foundation of application‐orientated optimisation. In this paper, a global model is built to study the chemical properties of PAW produced by a dielectric barrier discharge that is powered by nanosecond voltage pulses. The applied voltage is firstly repeated with 10 kHz frequency for 100 s, and then shut down for 200 s afterglow, providing a long‐term evolution regarding the production and consumption of some typical reactive oxygen/nitrogen species (RONS) in PAW. The calculated results agree principally with experimental measurements from literature. During the pulsed discharge, the water gradually acidises, and the long‐lived species accumulate; while in the afterglow, most of the aqueous RONS decay rapidly, except for O3aq, , H2O2aq and N2Oaq, which might be the main sources to sustain long‐term effects. Furthermore, the effects of applied voltage and gap distance on RONS are investigated. Correlation analyses from Pearson correlation coefficient indicate that gaseous RONS are more sensitive to the gap distance, while the aqueous ones are more sensitive to the voltage amplitude, suggesting the possibility to independently regulating the gaseous and aqueous chemistry.

Determination of polyphenol compounds in medicinal plants of local habitat and their importance for health

Objective: Assess the possibility of using some medicinal plants containing polyphenolic compounds (tannins and gallic acid) in medicine. Materials and methods: The Folin-Ciocalteu reagent spectrophotometry method is used to determine the amount of polyphenolic compounds. The gallic acid solution was selected as the standard sample. The objects of the study were dry specimens of plants: Oak Bark (quercus cortex), Rhizomes of Bistorta officinalis (bistortae rhizomata), Galls of Oak leaves (gallae turcicae), Rhizomes of Potentilla erecta (tormentillae rhizomata). Experimental samples in the form of aqueous and alcoholic extracts are made from this dry raw material. Results: Studies have shown that all selected plants have sufficient tannin content to confirm their healing properties. The largest number was found in the galls of oak leaves. Alcohol extracts extracted polyphenolic compounds from plant raw materials better than aqueous ones, but the difference is relatively small. Therefore, aqueous extracts can be used as therapeutic drugs for those who are contraindicated alcohol extracts. Conclusions: The studied dry specimens of plants (oak bark (quercus cortex), rhizomes of snake mustard (bistortae rhizomata), galls of oak leaves (gallae turcicae), rhizomes of erect cinquefoil (tormentillae rhizomata)) contain polyphenolic compounds (tannin and gallic acid) in sufficient quantities to provide medicinal effect. It has been shown that the extraction of polyphenolic compounds from plant materials using alcohol solutions is more efficient than aqueous extracts. It is recommended to use herbal products with tannins in medicinal practice.

Assessment of Antimicrobial Activity of Ethanolic and Aqueous Extracts of Aesculus hippocastanum L. (Horse Chestnut) Bark against Bacteria Isolated from Urine of Patients Diagnosed Positive to Urinary Tract Infections

The search for new antimicrobials is essential to address the worldwide issue of antibiotic resistance. The present work aimed at assessing the antimicrobial activity of Aesculus hippocastanum L. (horse chestnut) bark against bacteria involved in urinary tract infections (UTIs). Bioactive compounds were extracted from A. hippocastanum bark using water and ethanol as solvents. The extracts were tested against 10 clinical uropathogenic strains including five Gram-positive and five Gram-negative bacteria. Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 25922 were used as reference bacteria. The susceptibility to antibiotics was assessed using the Kirby Bauer disc diffusion method and the antibacterial activity of the extracts was evaluated using the well diffusion method. The Minimum inhibitory concentration (MIC) and the minimum bactericidal concentrations (MBC) were asseded by the microdilution method. A. hippocastanum bark possessed a dry matter content of 65.73%. The aqueous extract (AE) and ethanolic extract (EE) showed a volume yield of 77.77% and 74.07% (v/v), and a mass yields of 13.4% and 24.3% (w/w) respectively. All the bacteria were susceptible to amoxiclav, imipenem and ceftriaxone but the clinical strains were resistant to at least one antibiotic. Kocuria rizophilia 1542 and Corynebacterium spp 1638 were the most resistant bacteria both with multidrug resistance index of 0.45. Except AE on Proteus Mirabilis 1543 and Enterococcus faecalis 5960 (0 mm), both AE and EE were active against all the microorganisms tested with inhibition diameters (mm) which ranged from 5.5-10.0 for AE and 8.0-14.5 for EE. The MICs of EEs varied from 1-4 mg/mL while those of AEs varied from 4-16 mg/mL. The ethanolic extracts (EE) were overall more active than the aqueous ones. The A. hippocastanum bark extracts had overall weak antibacterial activity (MIC ≥0.625 mg/mL) and bacteriostatic potential (MBC/MIC ≥16) on both Gram-positive and Gram-negative bacteria.

Rechargeable hybrid organic Zn battery (ReHOZnB) with non-flammable electrolyte

ReHOB has been constructed by adopting intrinsically safe organic electrolyte through the replacement of the traditional aqueous electrolyte that displayed good cycling stability with TTFP additive. • Aqueous electrolytes for Zn anode have been replaced by TMP based electrolyte. • The strategy addressed safety concerns along with high Zn reversibility. • Zn/Na 2 Mn[Fe(CN) 6 ] battery exhibited excellent stability with TTFP- additive. Zn-based rechargeable batteries suffer from thermodynamic instability of Zn anode in aqueous electrolytes that results in low Coulombic efficiencies (CEs) and decreased anode reversibility. Therefore, as an alternative, non-aqueous Zn-battery chemistry has gained significant attention in the recent times that can effectively resolve the issues of thermodynamic instability along with improvement in CE of Zn plating/stripping. However, the adoption of organic electrolytes over aqueous ones throws a serious safety challenge. In this work, traditional aqueous electrolytes have been replaced by an intrinsically safe organic electrolyte in dual-ion Zn batteries to construct a rechargeable hybrid organic Zn battery (ReHOZnB) that effectively addresses the safety concerns along with providing highly reversible Zn anode. The Zn/ Na 2 Mn[Fe(CN) 6 ] (Na 2 MnHCf) battery delivered a reversible capacity of 89.3 mAh g −1 at a C-rate of 1 (1C = 160 mA g −1 ) exhibiting long term cycling stability with a capacity retention of 77% (66%) after 1000 (2000) charge–discharge cycles. The cycling performance has been stabilized through in-situ generation of cathode electrolyte interphase (CEI). This works provides an alternate electrolyte for the development of safe Zn batteries.

Polyphenolics profile effects upon the antioxidant and antimicrobial activity of propolis extracts

Propolis, a complex bee product, is a source of numerous bioactive principles, beneficial for human health, therefore it is intensively studied. In the present work, extracts of propolis from Bihor Romanian County were studied to identify the relationship between the polyphenolic derivatives profile and their antioxidant and antimicrobial activity. Extracts were obtained using water and 25%, 50%, and 70% ethanolic solutions (w/w), at 2:1, 4:1, and 6:1 liquid: solid ratios (w/w). 21 polyphenolic derivatives were quantified by UHPLC-MS, proving that the extracts composition strongly depends on the solvent. The sum of quantified polyphenolics extracted varied between 1.5 and 91.2 mg/g propolis. The antioxidant capacity was evaluated using the free radicals 2,2’-azino-bis (3-ethylbenzothiazoline-6 sulfonic acid) diammonium salt (ABTS) and 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging methods. Antimicrobial efficiency was tested against Gram-positive (B. subtilis), Gram-negative bacteria (E. coli), and fungi (C. albicans) by disc-diffusion method. All extracts, even the aqueous ones, demonstrated antibacterial and antifungal activity. Chemometric methods (partial least squares) and a saturation-type model were used to evaluate the contribution of various bioactive principles in building the antioxidant capacity of extracts. Both experimental and modelling results show that 50% ethanolic extracts provide a rich polyphenolics profile and ensure a good antioxidant capacity.

Modeling Chemical Reactivity at the Interfaces of Emulsions: Effects of Partitioning and Temperature.

Bulk phase chemistry is hardly ever a reasonable approximation to interpret chemical reactivity in compartmentalized systems, because multiphasic systems may alter the course of chemical reactions by modifying the local concentrations and orientations of reactants and by modifying their physical properties (acid-base equilibria, redox potentials, etc.), making them—or inducing them—to react in a selective manner. Exploiting multiphasic systems as beneficial reaction media requires an understanding of their effects on chemical reactivity. Chemical reactions in multiphasic systems follow the same laws as in bulk solution, and the measured or observed rate constant of bimolecular reactions can be expressed, under dynamic equilibrium conditions, in terms of the product of the rate constant and of the concentrations of reactants. In emulsions, reactants distribute between the oil, water, and interfacial regions according to their polarity. However, determining the distributions of reactive components in intact emulsions is arduous because it is physically impossible to separate the interfacial region from the oil and aqueous ones without disrupting the existing equilibria and, therefore, need to be determined in the intact emulsions. The challenge is, thus, to develop models to correctly interpret chemical reactivity. Here, we will review the application of the pseudophase kinetic model to emulsions, which allows us to model chemical reactivity under a variety of experimental conditions and, by carrying out an appropriate kinetic analysis, will provide important kineticparameters.

Effect of ms-substitution on aggregation behavior and spectroscopic properties of BODIPY dyes in aqueous solution, Langmuir-Schaefer and poly(methyl methacrylate) thin films

It is well known that boron-dipyrromethene (BODIPY) dyes have a remarkable combination of photophysical and photochemical properties, which are significant for practical use. Unfortunately, the application of BODIPYs in optical devices and biosensorics is severely limited due to the aggregation quenching effect (ACQ), the effects of the internal filter and/or the formation of excimers. One way to prevent fluorescence quenching is to synthesize new molecules BODIPY with a highly complicated structural organization or hybrid systems based on them. But in this paper, we demonstrate that the introduction of simple aliphatic or aryl substituents into the ms-position of the BODIPY molecule is an effective way to control the aggregation in various states: thin mono- and multilayer Langmuir-Schaefer (LS) films, polymer films and concentrated solutions, including aqueous ones. The results of experimental studies of the aggregation behavior of BODIPYs (BDP1-BDP3) are in good agreement with the theoretical calculations data of di- and tetramers, as well as multilayer packing. This allows to adjust the spectral properties of luminophores to the most possible types of their real applications in practical areas.

Optical lithium sensors

This review highlights the different strategies used for the design of Li + probes using color luminescence change, as well as lifetime variations. Optical Li ion detection and quantification, in the fields of biology and Li-ion battery, is currently in progress. The development of in situ Li + probes appeared to be challenging and constitutes a novel way to improve the Li + monitoring for patients or to increase the Li-ion battery security. Dr. Elise Villemin and Dr. Olivier Raccurt (Univ. Grenoble Alpes, French Commission for Atomic and Alternative Energies (CEA)). • State of the art of Li + ion probes using color luminescence change, as well as lifetime variations. • Li + ion probes classified by different strategies based on photophysical and photochemical mechanisms. • Li ion detection and quantification, in the fields of biology and Li-ion battery. • Major requirements for in situ Li + optical probes in health and Li-ion battery security and aging. The selective detection and quantification of lithium cations in various environments, such as aqueous ones (for biological and environmental applications) or others (for battery application) responds to a growing demand. Among the different methods for signal detection, the optical approaches, such as colorimetry or luminescence, requires a fast and reproducible implementation. In this Review, we provide an overview of the different strategies used for the design of Li + probes using colour and luminescence change, as well as lifetime variations. The question of reversibility of Li + coordination in optical lithium probes is highlighted. Requirements and perspectives about the development of innovative optical lithium sensors for in-situ applications are finally discussed.