Search

The prevention of drying-induced cracking is crucial in maintaining the mechanical integrity and functionality of colloidal deposits and coatings. Despite exploring various approaches, controlling drying-induced cracking remains a subject of great scientific interest and practical importance. By introducing chain-like particles composed of the same material and with comparable size into commonly used colloidal suspensions of spherical silica nanoparticles, we can significantly reduce the cracks formed in dried particle deposits and achieve a fivefold increase in the critical cracking thickness of colloidal silica coatings. The mechanism underlying the crack suppression is attributed to the increased porosity and pore sizes in dried particle deposits containing chain-like particle, which essentially leads to reduction in internal stresses developed during the drying process. Meanwhile, the nanoindentation measurements reveal that colloidal deposits with chain-like particles exhibit a smaller reduction in hardness compared to those reported using other cracking suppression approaches. This work demonstrates a promising technique for preparing colloidal coatings with enhanced crack resistance while maintaining desirable mechanical properties. [ABSTRACT FROM AUTHOR]

A general cobalt-catalyzed α-alkylation of nitriles with alcohols is reported. Utilizing this straightforward borrowing hydrogen methodology, a series of substituted and functionalized nitriles can be easily coupled with benzylic, heterocyclic, and aliphatic alcohols to prepare diverse functionalized nitriles in good to excellent yields (>70 examples). Key for this synthesis is the use of specific cobalt-nanoparticles supported on N-doped carbon, which were conveniently prepared by pyrolysis of a templated material generated in situ by mixing cobalt chloride, zinc chloride, D -glucosamine hydrochloride, and colloidal silica, and subsequent removal of the silica. [ABSTRACT FROM AUTHOR]

In this study, 3D printable organic-inorganic resins were developed using glycerol dimethacrylate, which can be synthesised from glycerol obtained as a by-product of the biodiesel production process, and wollastonite synthesised from reagent-grade materials, the by-product of the aluminium fluoride manufacturing process, silica gel waste or natural rock. The developed recyclable waste-based material was proven to be compatible with the widely available desktop DLP 3D PICO2 39 printer. It allowed straightforward additive manufacturing of true 3D structures with sub-millimetre spatial definition using standard printing parameters. This opens the way for the production of inorganic objects from reusable industrial waste. [ABSTRACT FROM AUTHOR]

Colloidal silica-bonded castables offer several advantages compared to traditional calcium aluminate cement (CAC)-bonded castables, including lower torque values during mixing, superior drying properties, and a lower CaO content. Nevertheless, information on the combination of CAC and colloidal silica is limited, and the effect of CAC additions on the drying properties of colloidal silica-bonded castables remains unknown. In this study, these drying properties were measured by rapidly heating 400 kg samples to 500 °C and assessing the resulting damage to each sample. Additionally, the physical and chemical properties of small-scale samples were analyzed to evaluate the impact of CAC addition. The analyzed properties included cold crushing strength (CCS), density, permanent linear change (PLC) and weight loss. The microstructure of the samples was investigated by FESEM and EDS. The results indicate that adding 1.5 wt.% increased the cold crushing strength at 20 °C, while lower CAC amounts had no noticeable effect. A mullite phase was observed in the sample without CAC, and correspondingly, anorthite was found in those with CAC additions. The samples exhibited significant differences in the drying tests, with the degrees of damage increasing with the CAC addition. [ABSTRACT FROM AUTHOR]

The article discusses the synthesis of aryl benzothiazole derivatives using microwave-assisted phase transfer catalysis, highlighting their potential as anticancer agents. Various synthetic methods and reactions are explored, with a focus on optimizing reaction conditions for high yields. The synthesized compounds are tested for anticancer activity against different cancer cell lines, showing promising results. The study aims to provide a convenient method for preparing aryl benzothiazoles and stimulate further research into their anticancer potential. [Extracted from the article]

Sodium alkylbenzene sulfonates (ABS), or linear alkylbenzene sulfonates (LAS), are among the most common synthetic anionic surfactants and water pollutants, capable of causing both acute and chronic toxic effects on aquatic organisms. The selective determination of sodium alkylbenzene sulfonates as a distinct class of anionic surfactants in complex natural matrices is feasible by gas chromatography with mass spectrometric detection (GC–MS) in the form of linear alkylbenzenesulfonic acid methyl esters (LABSA ME). The behavior of LAS and LABSA ME was studied under ascending high-performance thin-layer chromatography (HPTLC) using Kieselgel 60 F254 and Sorbfil plates to purify extracts and preconcentrate analytes. A mixture of n-hexane with methanol (23 : 1, v/v) is proposed as a mobile phase. Under these conditions, sodium alkylbenzene sulfonates remain at the start line, while their derivatives (LABSA ME), obtained by methylation with trimethyl orthoformate in the presence of trifluoroacetic acid (yield η = 98%), form zones characterized by retention factors Rf of 0.62–0.71 on Kieselgel 60 F254 and Sorbfil plates, respectively. The repeatability of Rf values is characterized by a relative standard deviation of 6.1 and 5.9%, respectively (n = 16). The completeness of the extraction (95.0–100.0%) of analytes from the plates is noted using descending HPTLC with acetonitrile. The applicability of the HPTLC method for preconcentrating analytes and purifying extracts is demonstrated using real water samples. Using GC–MS with electron impact ionization, concentrations of sodium alkylbenzene sulfonates were found in water sampled from the southern basin of Lake Baikal at a depth of 400 m (0.24 ± 0.02 µg/L) and in water obtained from melting snow collected from the ice of the Krestovka River at its mouth near the settlement of Listvyanka (31.1 ± 1.0 µg/L). [ABSTRACT FROM AUTHOR]

The aim of this study was to develop and validate a High-Performance Thin Layer Chromatographic (HPTLC) method for simultaneous determination of ceftriaxone and ceftriaxone e-isomer in powder for injection formulation. Ceftriaxone sodium injection is an antibiotic that used globally. It has Z/E geometrical conformation, in which ceftriaxone sodium and 3 ene-isomer have Z- conformation while (E)-isomer has E- conformation and the potential toxicity of ceftriaxone (E)-isomer has been reported. Thus, to safeguard the public health, a simple and easy to use, rapid and reliable method was developed for qualitative and quantitative determination of ceftriaxone sodium and its (E)–isomer. Samples were applied on HPTLC glass plates precoated with silica gel 60F254 by using Linomat semi-auto sampler. Separation was carried out using acetone, triethyl amine, water, chloroform and ethyl acetate as a mobile phase in different ratios. The Rf values of separated compounds were 0.51 ± 0.01 and 0.62 ± 0.01 for ceftriaxone sodium and ceftriaxone (E)-isomer respectively. The method was validated by studying Specificity, Linearity, Accuracy, Precision, Robustness, Limit of Detection (LOD) and Limit of Quantification (LOQ) and Solution stability. The developed method was successfully, sensitive, simple, precise, accurate, robust and applicable for the simultaneous determination of ceftriaxone sodium and ceftriaxone (E)-isomer in powder for injection formulation. [ABSTRACT FROM AUTHOR]

Silica gel‐modified hydratable magnesium carboxylate (HMC) is used as the binder for refractory castables. The mechanical strength and thermal shock resistance of HMC bonded and silica gel‐modified HMC‐bonded castables were compared. When the HMC/silica gel mass ratio is 2, the cold modulus of rupture, the hot modulus of rupture, the residual strength ratio after three‐times water quenching tests, and the matrix‐specific fracture energy of the castables were increased by 300%, 124%, 44.7%, and 132%, respectively, compared with HMC‐bonded castables. The characterization of microstructure evolution of silica gel‐modified HMC‐bonded castables indicated that a small amount of liquid phase generated is conducive to improving the high‐temperature mechanical properties. The in situ alumina‐rich spinel and needle‐like mullite toughened the matrix and enhanced the thermal shock resistance of the castables by "microcrack generation" and "preventing crack propagation" mechanisms. [ABSTRACT FROM AUTHOR]

The design integration of absorption and adsorption cooling systems is a recently emerging research field in which the inherent advantages of both these systems are intended to be combined so as to maximize system performance. However, a vast majority of the conventional integration approaches reported in the literature still suffer from the following drawbacks: (a) the inability to provide a continuous cooling effect of the integrated design during the switching period of the adsorption component, (b) the lack of incorporation of the mass/heat recovery cycles and its subsequent effects upon the integrated performance, and (c) the lack of functional dependence of all thermodynamic variables including heat capacities and adsorption enthalpy upon operational parameters such as temperature and pressure. This study presents the first attempt of a numerically validated performance prediction of such an integrated system with parallel functionality to facilitate a continuous cooling operation. An empirical model of mass recovery cycle has been formulated for the very first time which adequately describes the sorption dynamics during mass transfer. All thermodynamic variables have been expressed as functions of operational parameters during the cooling cycle. For a mean driving temperature predicted to be as low as 38 °C and a mean cycle time of 11.82 min, the proposed integrated design has been predicted to yield a cycle-averaged specific cooling power of 48.93 W kg−1 and a minimum achievable coefficient of performance of 0.74 compared to the corresponding values of 27.64 W kg−1 and 0.57 for the benchmark stand-alone silica gel/water adsorption chiller. [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chemical defence in insects is an increasingly popular subject of research and has the potential for providing unexplored compounds with unknown properties for drug and repellent discovery, so the secretions of various species of insects are currently being studied, and new ways of collecting these secretions are being sought. Silica gel and activated carbon were used as absorbents to collect the sprayed defensive secretion of Eurycantha calcarata. Using gas chromatography coupled with mass spectrometry, 49 compounds were identified, including 19 carboxylic acids, nine esters, ten alcohols, five hydrocarbons, and other organic compounds. The most abundant two compounds from each group were: hexadecanoic acid, octadecanoic acid, 9-hexadecenoic acid octadecyl ester, hexadecanoic acid tetradecyl ester, octacosanol, triacontanol, tridecane, and tetradecane. Silica gel turned out to be a better absorbent because it captured more compounds than the activated carbon. The mass of the absorbent did not affect the quality of the analyses. This paper is the first describing the volatile secretions emitted by phasmid representatives that originate from abdominal structures rather than the glands on prothorax. The presented results of the analyses and the known properties of the detected compounds give grounds for the conclusion that these secretions are of importance for defence in this species of phasmid. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to design a low-cost, simulation training platform for the ligation of deep dorsal vein (DVC) complex in radical prostatectomy and validate its training effectiveness. Methods: A simplified prostate urethra model was produced by 0-degree silica gel and pulse pressure banding. This model was placed on a slope of about 30 degrees using cardboard to thus creating a narrow environment of the pelvis. The DVC ligation was performed by a 2D laparoscopy simulator. A total of 27 participants completed the study include 13 novices, 10 surgical residents and 4 urology experts. The novices were trained five trails with 24 hours interval, the residents and experts completed the DVC ligation once. The construct validity of this simulation training platform was performed by completing time, the GOALS (Global Operative Assessment of Laparoscopic Skills) and TSA (i.e. Task Specific Assessments) score. The face validity and content validity were performed by a specific closed-ended questionnaire. Results: There was no significant difference among three groups in demographic or psychometric variables (p > 0.05). Compared to the novices, the residents spend a shorter time to complete the DVC ligation (p < 0.05) and had higher GOALS scores (p < 0.05), but had no significant difference in TSA scores (p > 0.05). Additionally, the experts groups had a better performance compared to residents group in the completing time (p < 0.05), GOALS score (p < 0.05) and TSA score (p < 0.05). The learning curve of novices significantly promoted along with the increased times of training. Almost 90 percent of subjects considered that this simulator had a good performance in the realism and practicability. Conclusion: We developed a novel low-cost a simulation training platform for the ligation of deep dorsal vein complex in radical prostatectomy, and this simulator had a good performance in the construct validity, face validity and content validity. [ABSTRACT FROM AUTHOR]

Recent advances in solid‐state nuclear magnetic resonance (NMR) spectroscopy, combined with dynamic nuclear polarization (DNP), quantum chemical DFT calculations, and gas‐phase NMR spectroscopy investigating the structure and reactivity of heterogeneous catalysts are reviewed. The investigated catalysts range from classical mononuclear catalysts, like immobilized derivates of Wilkinson's catalysts over binuclear catalysts such as the dirhodium paddlewheel catalyst to catalytic nanoparticles, employing various support materials, such as mesoporous silica gels, coordination polymers, and biomaterials such as cellulose. [ABSTRACT FROM AUTHOR]

A novel, environmentally friendly, and sensitive HPTLC method has been developed and validated for simultaneous quantification of duloxetine (DLX) and tadalafil (TDL) in their pure state, laboratory-prepared mixtures, and spiked human plasma. This method is particularly important for patients dealing with depression and sexual issues, as it allows for the measurement of these co-administered antidepressant and sexual stimulant drugs in biological fluids. The separation process employed a stationary phase of pre-coated silica gel 60 F254 and a mobile phase consisting of ethyl acetate, acetonitrile, and 33% ammonia (8:1:1, v/v). The optimized mobile phase resulted in well-defined bands for DLX and TDL, with Rf values of 0.3 and 0.8, respectively with dual-wavelength detection at 232 nm for DLX and 222 nm for TDL. Polynomial regression analysis revealed exceptional linearity for both drugs, with correlation coefficients of 0.9999 over concentration ranges of 10–900 ng/band for DLX and 10-1200 ng/band for TDL. The quantitation limits were 8.2 ng/band for DLX and 8.6 ng/band for TDL, while the detection limits (LOD) were 2.7 ng/band for DLX and 2.8 ng/band for TDL. The validation of this method followed the guidelines set by the International Council for Harmonization (ICH). Additionally, the suggested method's greenness was assessed by means of four up-to-date ecological tools, namely the Eco-Scale, the National Environmental Method Index (NEMI), the Green Analytical Procedure Index (GAPI), and the Analytical Greenness metric approach (AGREE). The proposed method was also assessed using the Blue Applicability Grade Index (BAGI), a recently developed metric for assessing the practicality (blueness) of procedures. [ABSTRACT FROM AUTHOR]

A series of chromium oxide catalysts supported on SiO2 with 5 wt % chromium were synthesized and studied. Silica gel was synthesized by a procedure using the cetyltrimethylammonium bromide template and hydrocarbons capable of solubilization in CTMABr micelles, namely, hexane, cyclohexane, and toluene as "extenders." The resulting series of supports and catalysts were characterized by physicochemical methods: low-temperature adsorption of N2, XRD, SEM–EDX, and UV–Vis diffuse reflectance spectroscopy. The highest catalytic activity in propane dehydrogenation in the presence of CO2 was exhibited by the 5Cr/SiO2–hexane sample, whose surface contains Cr(III) coexisting with Cr(VI). At 750°C propane conversion was 59.8%; propylene selectivity, 56.2%. [ABSTRACT FROM AUTHOR]

Levocetirizine dihydrochloride is an effective antiallergenic drug applied mostly orally; however, developing a topical formulation for localized treatment could be beneficial. To achieve this, a modified formulation technique is necessary to enhance bioavailability efficiency and minimize possible side effects. Therefore, levocetirizine particles were prepared by immobilization on mesoporous silica material. Both the dihydrochloride form and its free base of levocetirizine were fixed on a silica-type Syloid support. Immobilization of the active ingredient levocetirizine in a free base form on a Syloid support by mixing in a dichloromethane solution provides better surface coverage (65.5%) than immobilization in the dihydrochloride form in water or methanol (24.5% for both). The successful binding of levocetirizine was confirmed by X-ray photoelectron spectroscopy and infrared measurements. The active ingredient in the form of hydrochloride is more likely to be in the pores, while the free base is bound to the surface in larger quantities. The time-dependent levocetirizine release showed that the liberation of the active ingredient from the Syloid is slower than the dissolution of the starting active ingredient itself, so it may be suitable for exerting a more reliable and prolonged local effect. A gel containing a Syloid-fixed levocetirizine free base was tested in vivo in a croton oil-induced ear edema mouse model. When compared to a reference gel, the half-dose formulation containing levocetirizine free base demonstrated a similar efficacy to Fenistil gel, indicating that the new formulation may offer superior effectiveness at lower doses. [ABSTRACT FROM AUTHOR]

The study examined the efficacy of additives in preventing the crystallization of functional ingredients during the spray-drying process. Spray-drying of a hydrophobic drug from alcohol in the presence of a hydrophilic carrier-forming agent was utilized as a representative scenario, which frequently leads to the crystallization of the main drug component induced by the drying process. Ibuprofen (IBP) and its four congeners were employed as representatives of readily crystallizable hydrophobic pharmaceutical compounds. Disaccharides were intentionally employed as components of the drug carrier to create conditions conducive to crystallization. Ten materials, including the IBP congeners, were investigated for their anti-crystallization properties. The findings indicated that additives with a hydrophobic moiety similar to that of IBP and a carboxylic acid salt moiety effectively prevented IBP and its congeners from crystallizing when the additive content was ≥0.2 g/g-drug during spray-drying and storage at 30 °C over silica gel. [ABSTRACT FROM AUTHOR]

Solid desiccants have been widely used in dehumidification systems, but the regeneration of desiccants is significant for the economy and environment protection. The regeneration performance of several typical solid desiccants was examined in a microwave combined hot air lab-scale setup. The shortest time required for desiccants happened in the combined heating. Among eight desiccants, zeolite in the combined drying took the shortest time to be regenerated. Activated alumina was the most difficult to be regenerated, and it in the hot air drying had the highest absorption capacity, while 3A (1.6–2.5) zeolite in the microwave and combined heating had the highest absorption capacity. Silica gels in all heating modes had the minimum absorption capacity. At low power levels (100-300W), the regeneration performance of the silica gels was prompted by the multi-magnetron radiation modes with the top one. The temperature distribution uniformity in silica gel was lifted with the assisted hot air drying. The multi-magnetron could ameliorate the microwave heating uniformity. The combined drying not only could lift the heating uniformity of the microwave, but also lowered the energy consumption by the traditional hot air drying alone. This study can provide basic data for the design and improvement of the desiccant rotors. [ABSTRACT FROM AUTHOR]

Nortriptyline HCl and pregabalin Tablet is used to treat neuropathic pain as well as mental or mood issues such as sadness, mood, feelings, anxiety and tensions. Very few analytical methods are available for the simultaneous estimation of nortriptyline HCl and pregabalin and no reports has been found for HPTLC method. In the current study, a reliable HPTLC method for the simultaneous measurement of nortriptyline HCl and pregabalin in pure forms and pharmaceutical formulations has been developed with ninhydrine post derivatization of pregabalin. The HPTLC method development was carried using silica gel G60 F254 as stationary phase and acetonitrile: methanol: triethylamine: water: formic acid (7:3:0.3:0.8:0.02 v/v/v/v/v) was used as mobile phase with saturation time of 20 min. The system was found to give a compact band for nortriptyline HCl (R f  = 0.523 ± 0.008) pregabalin (R f  = 0.279 ± 0.005). The developed method was found to be validated as per ICH Q2 (R1) guideline. The peak of nortriptyline HCl and pregabalin showed good linearity over the concentration range of 50–300 ng/band and 350–2250 ng/band, respectively, with a correlation coefficient of ˃0.995. The % recoveries of both drugs were found to be in the range of 98.84–101.87%. Statistical analysis proved that the method is selective, precise, robust and accurate for the estimation of nortriptyline HCl and pregabalin. [ABSTRACT FROM AUTHOR]

Ophthalmic pharmaceutical preparation containing antazoline (ANT) and tetryzoline (TET) is prescribed widely as an over the counter medication for allergic conjunctivitis treatment. Development of a selective, simple and environmentally friendly thin-layer chromatographic method established to determine both ANT and TET in their pure forms, pharmaceutical formulation and spiked aqueous humor samples. By using silica gel plates and means of a developing system consists of ethyl acetate:ethanol (5:5, by volume), the studied drugs separation was achieved, and scanning was carried out at 220.0 nm for the separated bands with a 0.2–18.0 μg/band concentration range for each of ANT and TET. Standard addition technique application was carried out to determine the proposed method validity. Statistical comparison was made between the proposed method and the official methods ANT and TET showing no significant difference concerning accuracy and precision. Furthermore, greenness profile assessment was accomplished by means of four metric tools, namely, analytical greenness, green analytical procedure index, analytical eco-scale and national environmental method index. Highlights Green TLC-densitometric determination of antazoline and tetryzoline. Applicability of analysis of studied drugs in eye drops and in rabbit aqueous humor samples. Greenness profile assessment was accomplished via four smart metric tools. [ABSTRACT FROM AUTHOR]

The grafting of trialkoxysilanes is the most common method for the surface functionalization of silica gel, and it is usually carried out in the presence of toluene or other solvents such as acetonitrile or acetone. Here, we replaced these solvents with alcohols to afford silica materials containing alkoxy groups linked to the silicon atom. The grafting of N,N-dimethyl-3-amino- or 3-amino-propyltrimethoxysilane was carried out in the presence of several alcohols containing an unsubstituted alkyl chain (C7 and C14), a PEG functionalized chain, or an amino-substituted chain (N,N-dimethylamino, pyridyl). Materials were characterized via solid-state 13C- and 29Si CPMAS NMR and thermogravimetric analysis to prove that alcohols are not "innocent" solvents but take part in the reaction and lead to [RSi(OR1)-(OSi)2] systems where the OR1 group proceeds from the alcohol used in the synthesis. As a proof of concept, we briefly studied the catalytic activity of some of these materials with the aim of showing how different modifications can influence the course of a selected reaction. Finally, a quaternary ammonium salt (QAS)-based silica was prepared containing both an alkyl-QAS and an alkoxy-QAS linked to silicon atoms. This could represent an interesting approach for the development of new antifouling-based materials and, overall, the described strategy could be useful for the preparation of new organosilica materials. [ABSTRACT FROM AUTHOR]

Organic compounds with antibacterial and antiparasitic properties are gaining significance for biomedical applications. This study focuses on the solvent-free synthesis (green synthesis) of 1,4-naphthoquinone or 2,3-dichloro-1,4-naphthoquinone with different phenylamines using silica gel as an acid solid support. The study also includes in silico PASS predictions and the discovery of antibacterial and antiparasitic properties of phenylaminonaphthoquinone derivatives 1–12, which can be further applied in drug discovery and development. These activities were discussed in terms of molecular descriptors such as hydrophobicity, molar refractivity, and half-wave potentials. The in vitro antimicrobial potential of the synthesized compounds 1–12 was evaluated against a panel of six bacterial strains (three Gram-positive: Staphylococcus aureus, Proteus mirabilis, and Enterococcus faecalis; and three Gram-negative bacteria: Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae). Six compounds (1, 3, 5, 7, 10, and 11) showed better activity toward S. aureus with MIC values between 3.2 and 5.7 μg/mL compared to cefazolin (MIC = 4.2 μg/mL) and cefotaxime (MIC = 8.9 μg/mL), two cephalosporin antibiotics. Regarding in vitro antiplasmodial activity, compounds 1 and 3 were the most active against the Plasmodium falciparum strain 3D7 (chloroquine-sensitive), displaying IC50 values of 0.16 and 0.0049 μg/mL, respectively, compared to chloroquine (0.33 μg/mL). In strain FCR-3 (chloroquine-resistant), most of the compounds showed good activity, with compounds 3 (0.12 μg/mL) and 11 (0.55 μg/mL) being particularly noteworthy. Additionally, docking studies were used to better rationalize the action and prediction of the binding modes of these compounds. Finally, absorption, distribution, metabolism, excretion, and toxicity (ADMET) predictions were performed. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets with high thermal diffusivity are being researched for their ability to improve the thermal characteristics of adsorbents. Similarly, ionic liquids with hydrophilic properties have shown promising sorption and thermal attributes. In this study, novel composite adsorbents are developed, comprising few-layered graphene nanoplatelets and specific ionic liquids (ethyl-methylimidazolium methanesulfonate (EMIMCH3SO3) and ethyl-methylimidazolium chloride (EMIMCl)), along with polyvinyl alcohol binder. The composites, known as GP-CL-30-CP and GP-CH3SO3-30-CP, each contain 30% ionic liquid content. The aim is to capitalise on the superior thermal properties of graphene nanoplatelets and the stability and solvation characteristics of ionic liquids to enhance water and cooling production in adsorption-based cooling and desalination processes, addressing challenges in the water–energy nexus. The findings revealed an improvement in the thermal diffusivity of the composites by 167%, which is 76 times higher than the baseline silica gel. There was an increase in water uptake from 0.3534 kg/kg for silica gel to 0.9648 kg/kg for the composites, representing a 174% enhancement in water sorption, and hence more freshwater water production. [ABSTRACT FROM AUTHOR]

This study delves into the effects of carbonation curing and autoclave–carbonation curing on the properties of calcium oxide–belite–calcium sulfoaluminate (CBSAC) cementitious material aerated concrete. The objective is to produce aerated concrete that adheres to the strength index in the Chinese standard GB/T 11968 while simultaneously mitigating CO2 emissions from cement factories. Results show that the compressive strength of CBSAC aerated concrete with different curing regimes (autoclave curing, carbonation curing, and autoclave–carbonation curing) can reach 4.3, 0.8, and 4.1 MPa, respectively. In autoclave–carbonation curing, delaying CO2 injection allows for better CO2 diffusion and reaction within the pores, increases the carbonation degree from 19.1% to 55.1%, and the bulk density from 603.7 kg/m3 to 640.2 kg/m3. Additionally, microstructural analysis reveals that delaying the injection of CO2 minimally disrupts internal hydrothermal synthesis, along with the formation of calcium carbonate clusters and needle-like silica gels, leading to a higher pore wall density. The industrial implementation of autoclavecarbonation curing results in CBSAC aerated concrete with a CO2 sequestration capacity ranging from 40 to 60 kg/m3 and a compressive strength spanning from 3.6 to 4.2 MPa. This innovative approach effectively mitigates the carbon emission pressures faced by CBSAC manufacturers. [ABSTRACT FROM AUTHOR]

A water-soluble ternary copolymer bearing carboxyl, sulfonic, and amide functional groups was synthesized using ammonium persulfate-catalyzed free radical polymerization in water, resulting in high monomer conversion. This copolymer was then complexed with aluminum sulfate, forming an admixture containing Al(SO4)(OH)·5H2O, which was subsequently combined with silica gel. Characterization revealed that the synthesized copolymer formed a large, thin membrane that covered both the aluminum compounds and the silica gel blocks. The introduction of this complex admixture, combining the copolymer and aluminum sulfate, not only reduced the setting times of the cement paste but also enhanced the mechanical strengths of the mortar compared to using aluminum sulfate alone. The complex admixture led to the formation of katoite, metajennite, and C3A (tricalcium aluminate) in the mortar, demonstrating significant linking effects, whereas pure aluminum sulfate could not completely transform C3S within 24 h. Further addition of silica gel to the complex admixture further shortened the setting times of the paste, slightly reduced compressive strength, but improved flexural strength compared to the initial complex admixture. The silicon components appeared to fill the micropores and mesopores of the mortar, accelerating cement setting and enhancing flexural strength, while slightly decreasing compressive strength. This study contributed to the development of new cementing accelerators with improved hardening properties. [ABSTRACT FROM AUTHOR]

The aerobic and rod-shaped FO1 strain of iron-oxidizing bacteria was isolated from electroplating wastewater sludge using colloidal silica plates. Bacterial growth occurred at 25–30°C (optimum temperature, 27°C), pH 2.0–3.5, and in the presence of 1.0–4.0% NaCl. The X-ray diffraction analysis identified the precipitates that were formed during cell growth as jarosite. A biochemical analysis, including the assessments of the whole-cell fatty acids, quinone, and DNA G+C contents, revealed that FO1 was closely related to the genus Acidihalobacter. The 16S rRNA sequence of the FO1 gene was similar to those of the Acidihalobacter prosperus DSM 5130 (97% similarity), Ah. aeolianus DSM 14174 (100%), and Ah. yilgarnensis DSM 105917 (100%) strains. Antibiotic sensitivity tests of strain FO1 revealed that it was tolerant for gentamicin, kanamycin, and tetracycline, whereas it was sensitive to ampicillin and chloramphenicol. Moreover, strain FO1 was able to grow in a microbial electrolysis cell with continuous reduction of Fe3+ to Fe2+ on the cathode, albeit with a slight inhibition of cell growth. This study provides information regarding the genetics, bioleaching of metals, and electrochemical cultivation of halotolerant iron-oxidizing bacteria in the genus Acidihalobacter. [ABSTRACT FROM AUTHOR]

Fabricating large-scale porous bioactive glass bone scaffolds presents significant challenges. This study aims to develop formable, in situ setting scaffolds with a practical gelation time of about 10 min by mixing 45S5 bioactive glass with sodium silicate (waterglass) and an acid initiator. The effects of pH (2–11), waterglass concentration (15–50 wt.%), and acid initiator type (phosphoric or boric acid) were examined to optimize gelation kinetics and microstructure. A 10 min gelation time was achieved with boric acid and phosphoric acid at various pH levels by adjusting the waterglass concentration. Exponential and polynomial models were proposed to predict gelation times in basic and acidic environments, respectively. The optical properties of the gels were studied qualitatively and quantitatively, providing insights into gelation kinetics and structure. Acidic gels formed smaller particles in a dense network (pores < 550 nm) with higher light transmittance, while basic gels had larger aggregates (pores ~5 µm) and lower transmittance. As the waterglass concentration decreased, pore size and transmittance converged in both groups. The onset of gelation was detected around 8 min using the derivative of light transmittance. This work identifies the key factors controlling waterglass gelation and their impact on gel structure, enabling the tailored creation of formable, in situ setting bioactive glass bone scaffolds. [ABSTRACT FROM AUTHOR]

Silicate gels have long been utilized as water shut-off agents in petroleum fields to address excessive water production. In recent years, nano-silica gel has emerged as a promising alternative to traditional silicate gels, offering potentially improved plugging performance. However, the long-term effectiveness of these gels remains uncertain, posing challenges to sustained profitability. Therefore, a comprehensive study spanning 6 months was conducted on fractured and induced channel samples treated with nano-silica gel of 75/25 wt% (silica/activator) at 200 °F. A comparative analysis was performed with samples treated using polyacrylamide/polyethyleneimine PAM/PEI gel (9/1 wt%) to compare the performance of both systems. Throughout the aging period in formation water at 167 °F, endurance tests were conducted at regular intervals, complemented by computed tomography (CT) scans to monitor any potential degradation. The results revealed nano-silica gel's superior long-term performance in plugging fractures and channels compared to PAM/PEI gel. Even after 6 months, the nano-silica gel maintained a remarkable 100% plugging efficiency at 1000 psi, with a maximum leak-off rate of 0.088 cc/min in the mid-fractured sample and 0.027 in the induced channel sample. In comparison, PAM/PEI gel exhibited a reduction in efficiency to 99.15% in the fractured sample (5.5 cc/min maximum leak-off rate) and 99.99% in the induced channel sample (0.036 cc/min maximum leak-off rate). These findings highlight the potential of nano-silica gel as a more durable water shut-off agent for managing water production in fractures and channels. [ABSTRACT FROM AUTHOR]

Silver-containing silica gel is a commonly used iodine waste adsorption material in post-treatment plants, and can be formed by adsorbing iodine with silver-containing silica gel, which provides a feasible method for treatment of radioactive iodine. The accurate determination of iodine content in iodine-containing silica gel samples can verify the adsorption efficiency of iodine and provide data support for the post-processing process. Silver ions and iodide ions in the iodine-containing silica gel samples form insoluble silver iodide during the dissolution process, it is difficult to quantitatively convert the iodide ions in silver iodide into soluble iodide ions, iodine elements or iodate ions. Therefore it is difficult to measures the iodine content in iodine containing silica gel samples. During the experiment, the effects of masking silver ions on iodide ions were considered. By checking the solubility product constant of the silver compound, the method of adding sulfide ions was used to generate a silver sulfide precipitate that was more difficult to dissolve than silver iodide, thus eliminating the interference of silver ion. The displaced iodide ions existed stably in alkaline solutions, and because of the high iodine content, inductively coupled plasma spectrometry (ICP-OES) was used to measure IS content. During the experiment, the effects of sodium sulfide add-on, ammonia concentration, ultrasound time, etc. on the results were investigated, and the ICP-OES method was used to measure the iodine content in the sample. Experimental results showed that the amount of sodium sulfide added was related to the silver content, excessive sulfide ions needed to be added to precipitate silver ions. Different ammonia concentrations affected the sensitivity of iodine, while the somication time had little effect on the results. The detection limit of the method was 0.52 mg/g after optimizing the experimental conditions, and two silica gel samples containing iodine and silver were measured 6 times, with an average value of 34.8 mg/g and 59.3 mg/g. The relative standard deviations were 2.7% and 2.0%, and the recovery of the spiked was 95. 0%--103%, which could meet the determination of iodine in iodine containing silica gel samples. [ABSTRACT FROM AUTHOR]

For the first time, two direct and eco-friendly chromatographic approaches were adapted for the simultaneous estimation of pheniramine maleate (PAM) and its major toxic impurity, 2-benzyl pyridine (BNZ). Method A used reversed-phase ultra-performance liquid chromatography; separation was achieved within 4 min using a C18 column with a developing system of methanol/water (60:40 v/v) with a 0.1 mL/min flow rate. Photodiode array detection was adjusted at 215 nm. The method was linear in the ranges of 5.0–70.0 and 0.05–10.0 µg/mL for PAM and BNZ, correspondingly. Method B used thin-layer chromatography; separation was applied on silica gel TLC F254 using ethanol/ethyl acetate/liquid ammonia (8:2:0.1, in volumes) at room temperature, at 265 nm. Linearity was assured at concentration ranges 0.5–8.0 and 0.1–3.0 µg/band for the two components, respectively. Generally, the new UPLC and TLC methods outperform the old ones in terms of quickness, greenness, and sensitivity. Concisely, the greenness features were partially achieved using the Green Analytical Procedure Index (GAPI) and the Analytical Greenness (AGREE) pictograms. In contrast, the usefulness of the novel approaches was assured via the Blue Applicability Grade Index (BAGI) tool. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central China Normal University is the property of Huazhong Normal University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the effect of using a hybrid solar thermal-activated adsorption desalination system for brackish water is evaluated under the climatic conditions of the Brazilian semiarid region. The proposed theoretical model utilizes climatic data from the meteorological station in Campina Grande, PB, and adsorptive kinetics data of Fuji Davison RD 260 silica gel to predict the performance indices of the specific daily water production (SDWP), specific cooling power (SCP), and coefficient of performance (COP) performance coefficients over a characteristic day. The SDWP value of 6.26 m3/ton, SCP ranging from 50 to 300 W/kg, and an average COP of 0.5 were obtained, considering variations in global horizontal irradiance in the ACDS system and transient ambient temperature. It was observed that both the production of desalinated water and the refrigeration effect increase with the rise in daily solar irradiance. The variation in the number of solar collectors used in the system and their optimality, as well as the variation in the salinity index of the feed source, impacted the evaluated performance coefficients. [ABSTRACT FROM AUTHOR]

This study investigates the removal of Congo red dye from aqueous solution using functionalized generation 3.0 and 5.0 Polyamidoamine dendrimer – silica gel composite (G-3PS, G-5PS). Fourier Transform-Infra Red spectroscopy, Brunauer Emmett and Teller, Thermogravimetric Analysis, pH at point of zero charge, and Scanning Electron Microscopy measurements have been applied to characterize the synthetic nanohybride composite, these techniques revealed the successful functionalization of both dendrimer molecules and subsequent immobilization onto silica gel. The implications of varying adsorption parameters such as contact time, initial concentration of adsorbate, temperature and pH on both composites were studied. Experimental data obtained from batch adsorption processes were fitted into two equilibrium isotherms (Langmuir and Freundlich) and 3 kinetic models (Pseudo-First-Order, Pseudo-Second-Order, Intra Particle Diffusion). Adsorption mechanism was mainly governed by film diffusion due to electrostatic interactions between the functionalized dendrimer surface and Congo red molecules. Thermodynamic parameters illustrate that the adsorption is endothermic and spontaneous. Findings suggest the Nanocomposites G-3PS G-5PS) are good adsorbents for the removal of Congo red dye from aqueous solutions. [ABSTRACT FROM AUTHOR]

Beta-galactosidase (EC 3.2.1.23), also known as lactase, is an exoglycosidase enzyme responsible for hydrolyzing the β-glycosidic bond between galactose and its organic moiety. This study focused on extracting, purifying, characterizing and immobilizing β-galactosidase from tomato leaves. The enzyme was successfully extracted using a 0.2 M sodium phosphate buffer at pH 6. To evaluate its chemical properties, the effects of temperature, pH, enzyme concentration and substrate concentration on enzyme activity were examined. The optimal temperature for β-galactosidase activity was found to be 50°C and the enzyme demonstrated the highest solubility at pH 6. The kinetic parameters of the free enzyme were determined, revealing a Michaelis constant (Km) of 0.1 mM and a maximum reaction velocity (Vmax) of 48.78 ìmol/min. These findings provide valuable insights into the enzyme's efficiency and behaviour under various conditions, which are essential for optimizing its application in industrial processes. [ABSTRACT FROM AUTHOR]

The preparation of fused silica glass with microstructural patterns has attracted considerable interest, and the process chain of using nano-silica powders mixed with organic polymers to prepare composites for molding, degreasing, and sintering provides a good solution. However, the potential negative effects of organic residues cannot be avoided. In this study, a pattern stencil replication method with silica gel using high-purity quartz fibers as reinforcement is proposed for preparing micropatterned fused silica glass. The microscopic morphology and mechanical properties before and after silica gel drying and the optical properties of fused silica glass obtained by sintering were evaluated via transmission electron microscopy), three-point bending strength test, scanning electron microscopy, X-ray diffraction spectrum analysis, ultraviolet–visible and infrared measurements. The results showed that quartz fiber as a reinforcer could shorten the drying time of the gel and did not degrade the quality of the fused silica glass obtained by sintering. Laser confocal test results showed that microlens arrays were generated by template replication, demonstrating the feasibility of molding fused silica lens arrays with small feature sizes and providing new ideas for the preparation of bulk fused silica glass or micropatterned glass. [ABSTRACT FROM AUTHOR]

A new benzofuran-type neolignan (1), two new phenylpropanoids (2 - 3), and one new C21 steroid (4) were isolated from the ethyl acetate extract of the roots of Dolomiaea souliei by chromatographic methods, including silica gel, ODS column chromatography, MPLC, and semi-preparative HPLC. Their structures were identified as dolosougenin A (1), (S)-3-isopropylpentyl (E)-3-(4-hydroxy-3-methoxyphenyl) acrylate (2), (S)-3-isopropylpentyl (Z)-3-(4-hydroxy-3-methoxyphenyl) acrylate (3) and dolosoucin A (4) through various spectroscopic techniques including 1D NMR, 2D NMR, IR, UV, HR ESI MS, ORD, and computational ORD methods. [ABSTRACT FROM AUTHOR]

AbstractA new sterol, aspersterol E (1), a newly discovered alkaloid, asperginine A (2), and five known compounds (3–7) were obtained from the endophytic fungus Aspergillus sp. S3 of Hibiscus tiliaceus Linn. The compounds were extracted from their fermentation products using silica gel, ODS C18, and semi-preparative HPLC. The structure of each compound was determined through spectroscopic analysis. All the obtained compounds (1–7) were evaluated for their cytotoxic activity against the mouse pre-gastric cancer cell line MFC by using the MTT assay. The IC50 values of compounds 1, 2, 3, and 5 were found to be 153.43 μM, 61.25 μM, 73.19 μM, and 181.69 μM respectively. [ABSTRACT FROM AUTHOR]

The degree of ease of use and the readily observable signals associated with the detection process are critical factors in determining the success of a detection strategy. Considering this perspective, we report the detection of phosgene by modulating the photophysical characteristics of a molecular probe, Xanth-NH2. The probe is non-emissive in nature, but the presence of phosgene facilitates the probe's radiative decay, which enables phosgene detection via fluorescence turn-on change. The fluorescence changes vary linearly with phosgene concentration, contributing to a nanomolar level detection limit for phosgene. Additionally, under a controlled set of conditions, the half-time for the reaction of Xanth-NH2 with phosgene is 68 s. To demonstrate the potential application of Xanth-NH2, probe-loaded paper strips or silica gel were developed as an economic tool for the detection of phosgene in vapor or solution phase. Phosgene detection has been accomplished with a portable UV light source and a smartphone to track minute changes during the detection event. [ABSTRACT FROM AUTHOR]

Human comfort and health are significantly affected by indoor humid environments. Traditional dehumidification methods in buildings often have the problems of high energy consumption, complex structures, and high maintenance costs. Given this, a ventilated roof desiccant bed was proposed in this paper. The heat and moisture transfer process during its regeneration phase was analyzed, a dynamic numerical model for heat and mass transfer was established, and a dynamic characteristics simulation study of the regeneration process was conducted, providing theoretical reference for its practical application. By comparing indicators such as moisture content, effective regeneration time, and regeneration rate, the regeneration characteristics of the desiccant bed under high and low solar radiation scenarios were analyzed. The results indicate that, under the same thickness of silica gel coating, the steady-state moisture content of the desiccant bed under high solar radiation conditions(average 654. 0 W/m²)is lower than that under low solar radiation conditions(average 305. 4 W/m²). The intensity of solar radiation enhances the regeneration of the desiccant bed, with a regeneration rate of 57. 3% under high solar radiation conditions, higher than 52. 6% under low solar radiation conditions. Under high solar radiation conditions, the average regeneration amount within the first 3 hours is 8. 31 g, and only 0. 30 g in the subsequent 3 hours, indicating that the regeneration of the desiccant bed can be basically completed within 3 hours in good weather. [ABSTRACT FROM AUTHOR]

This article discusses the discovery of triterpenoids and steroids from the plant Euphorbia hypericifolia, which is commonly used in traditional medicine. The researchers isolated 25 triterpenoids and nine steroids from the twigs and leaves of E. hypericifolia collected in China. Through spectroscopic experiments, the structures of these compounds were determined. The article provides NMR data for several chemical compounds, including Spiropedroxodiol and Stigmast-4-ene-6β-ol-3-one. The research was financially supported by the National Natural Science Founding of China and Students' Research and Training Funding of Yunnan Normal University. [Extracted from the article]

This article discusses the chemical composition of compounds found in the rhizomes of Hedychium convexum, a plant species commonly found in tropical Asia. The researchers collected the plant from China and conducted extractions and chromatographic separations to isolate and identify four compounds. The structures of these compounds were determined using spectroscopic methods. The document also provides information on other compounds isolated from H. convexum, including their chemical formula, physical properties, and spectroscopic data. The research was supported by the Key Laboratory and Science and Technology Innovation Team of Higher Education in Yunnan, China. [Extracted from the article]

This article, published in the Chemistry of Natural Compounds journal, explores the secondary metabolites of Cinnamomum burmanni, a spice commonly used in Indonesia. The study identifies 22 compounds from the stems of the plant, including triterpenoids, coumarins, steroids, benzenoids, lignans, oxysporones, and apocarotenoids. Many of these compounds are reported for the first time in this plant. The article provides detailed information on the extraction and isolation methods used, as well as the physical and spectroscopic properties of the compounds. The document also acknowledges the support of Yuan's General Hospital for the investigation. Overall, this report offers valuable insights into the chemical composition of Cinnamomum burmanni and is a useful resource for library patrons conducting research in this area. [Extracted from the article]

Background: In recent years, the advancement of computational chemistry has offered new insights into the rational design of molecularly imprinted polymers (MIPs). From this aspect, our study tried to give quantitative parameters for evaluating imprinting efficiency and exploring the formation mechanism of MIPs by combining simulation and experiments. Methods: The pre-polymerization system of sulfadimethoxine (SDM) was investigated using a combination of quantum chemical (QC) calculations and molecular dynamics (MD) simulations. MIPs were prepared on the surface of silica gel by a surface-initiated supplemental activator and reducing agent atom transfer radical polymerization (SI-SARA ATRP). Results: The results of the QC calculations showed that carboxylic monomers exhibited higher bonding energies with template molecules than carboxylic ester monomers. MD simulations confirmed the hydrogen bonding sites predicted by QC calculations. Furthermore, it was observed that only two molecules of monomers could bind up to one molecule of SDM, even when the functional monomer ratio was up to 10. Two quantitative parameters, namely, the effective binding number (EBN) and the maximum hydrogen bond number (HBNMax), were defined. Higher values of EBN and HBNMax indicated a higher effective binding efficiency. Hydrogen bond occupancies and RDF analysis were performed to analyze the hydrogen bond formation between the template and the monomer from different perspectives. Furthermore, under the influence of the EBN and collision probability of the template and the monomers, the experimental results show that the optimal molar ratio of template to monomer is 1:3. Conclusions: The method of monomer screening presented in this study can be extended to future investigations of pre-polymerization systems involving different templates and monomers. [ABSTRACT FROM AUTHOR]

The Aromatic Silica Gel derivatives were prepared from the preparation of the Dasanium salt in a cooled acid medium, and mixed with the silica gel salt to obtain organic silica ; and from the Infrared Spectrum (FT - IR) clear values of the aromatic ring at the stress stretch (ѵC = C) at the range (1515 – 1645) cm-1. Also, the images of the Scanning Electron Microscope (SEM) showed clear distances in the material in a partially deformed and crystalline form after the embellishment process. [ABSTRACT FROM AUTHOR]

This document provides detailed information on the synthesis and characterization of several compounds, including their chemical composition, yield, melting point, and spectroscopic data. The authors acknowledge financial support from the Research Council of the Islamic Azad University, Rasht Branch, and no conflicts of interest were reported. [Extracted from the article]

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Shear thickening fluids (STF) represent stabilized and concentrated colloidal suspensions, wherein hard nanoparticles are dispersed within a liquid medium (polymer). Under the influence of impact forces, they exhibit non-Newtonian behavior, effectively dissipating energy through shear thickening. The optimization of the dispersion medium's viscosity is critical, as it not only fosters shear thickening but also facilitates proper particle dispersion. This study investigates the impact of graphene oxide (GO) as an additive in STFs, analyzing both static and dynamic rheological properties. STFs were formulated using colloidal silica particles (600 nm) and polyethylene glycol (PEG-200), with varied concentrations of GO particles (0.12–0.5 % w/W). The systems underwent comprehensive analysis concerning steady-state and dynamic-state rheological behavior under diverse conditions. The findings reveal that the inclusion of GO augments both static and dynamic rheological properties, reaching an apex at an optimal concentration of 0.36 % w/W. GO functions as a network builder within the STF, interacting with the existing particle network to create a more robust and interconnected structure. These enhanced properties underscore the potential of the synthesized STF for applications requiring impact resistance. [ABSTRACT FROM AUTHOR]

An inexpensive membrane with high proton conductivity and high fuel cell performance, which can be an alternative to Nafion for PEMFC (Proton exchange membrane fuel cell), will overcome the obstacle to widespread commercialization of fuel cells due to high cost. For this purpose, SPEEK (sulfonated polyether ether ketone)-PVA (polyvinyl alcohol) blend membranes with colloidal silica additives were synthesized in this study. Ludox AS-40 was used as the colloidal silica source and the blend membrane was prepared by solution casting method. Water uptake capacity, swelling property, size change, dynamic mechanical analysis, ion exchange capacity, AC impedance analysis, hydrolytic and oxidative stability experiments of the synthesized Ludox additives blend membranes for fuel cell application were carried out, and the membranes were also characterized by FTIR (Fourier transform infrared) analysis. While the water uptake capacities of SPEEK/PVA membranes containing 1% Ludox, 5% Ludox, and 10% Ludox at room temperature were found to be 14.08%, 14.84%, and 16.6%, respectively, the water uptake capacities at 80oC increased to 14.73%, 15.17%, and 17.11%. The proton conductivities of 1% Ludox, 5% Ludox and 10% Ludox doped SPEEK/PVA membranes at 80oC were 0.25 S/cm, 0.56 S/cm, and 0.65 S/cm, respectively. Similarly, ion exchange capacities were determined to be 1.41 meq/g, 1.63 meq/g, and 1.71 meq/g, respectively. All Ludox-added membranes exhibited excellent hydrolytic stability, retaining approximately 88% of their mass after 650 h. In addition, in oxidative stability experiments carried out in 4 ppm Fe+ 2 at 80oC, the 10% Ludox-added membrane exhibited the highest weight loss of 88.8% at the end of 24 h, while the 5% Ludox-additive membrane retained 91.6% of its total weight. Considering the proton conductivity and longevity tests of the synthesized membranes, they are thought to be promising structures. [ABSTRACT FROM AUTHOR]

Objectives: Daniellia oliveri Rolfe is a well-known plant of Fabaceae family whose previous phytochemical and pharmacological studies led to the identification of triterpenoid, phenol, anthraquinone oxalate with antioxidant, antibacterial and antifungal activities. This study aimed to investigate chemical constituents and evaluate the antimicrobial potency of the root of D. oliveri. Methods: The methanol extract of the root barks of D. oliveri was subjected to silica gel chromatographic separation. The structures of the isolated compounds (1 - 9) were determined by analyzing their spectrometric and spectroscopic spectra. Single-crystal-Xray analysis was used to establish the absolute skeletal structure of compound 1. Crude extract, fractions and compounds were investigated against four bacteria vis Pseudomonas aeruginosa 27853, Escherichia coli 5, Staphylococcus aureus 25923 and Streptococcus sp. 9619 and, two yeast vis Candida albicans 14053 and Candida tropicalis 018 using broth microdilution method. Results: The phytochemical prospection of the methanol extract of D. oliveri allowed the isolation of a naturally crystallized diterpenoid type furolabdane: polyalthic acid 1, as well as eight amorphous compounds (2 - 9). Among the tested samples, the crude extract, fractions and compounds selectively showed inhibitory effects against the tested microorganisms with MIC values ranging from 4 to 1024 μg/mL. Fraction D1 and compounds 1, 4, 7, 8 and 9 exhibited the broadest antimicrobial effects among fractions and compounds while D5 and compound 1 showed the best activity with MIC values of 16 and 4 μg/mL respectively against E. coli which appeared to be the most sensitive strain. Conclusion: Polyaltic acid (1) showed the best activity with significant MIC value of 4 μg/mL identical to that of ceftazidine against E. coli. The MIC values of the active compounds 1, 4 and 7 are comparable to those of ceftazidime. Then, these compounds from natural origin, could serve as markers in the standardization of Daniellia plant as phytomedicine. [ABSTRACT FROM AUTHOR]