Simple Dissolution Research Articles

Simple device for dissolution and sample transfer for applications in spin-hyperpolarization

ABSTRACTRapid dissolution and transfer of samples are crucial steps in hyperpolarization methods such as dissolution dynamic nuclear polarization (dDNP) and quantum-rotor-induced polarization (QRIP). Here we introduce a simple and modular dissolution transfer device, and we demonstrate its application for QRIP. This device operates with low pressures and solvent volumes compared to state-of-the-art dDNP setups. On the other hand, transfer times are longer, although sufficient for 13C NMR spectroscopy. Our approach does not require an additional cryostat.

Analysis of triglycerides in butter, plant oils, and adulterated butter with LPGC-MS

This work is focused on the detection of butter adulteration by sunflower and rapeseed oils using low pressure gas chromatography mass spectrometry (LPGC-MS). The method is based on simple dissolution of triglycerides from butter samples in chloroform and their direct analysis with LPGC-MS. The method allows the detection of characteristic triglycerides as butter adulteration markers and their quantification in different samples, with the possibility to quantify plant oil addition to butter at 0.45% level (using m/z = 600.4 for rapeseed oil) and 0.15% for sunflower oil (using m/z = 598.4). Ten different commercial butters were tested for the presence of sunflower and rapeseed oil. Interestingly, the addition of rapeseed oil up to 1.2% was recorded in one butter brand.

Analysis of Nucleation Phenomena for Metallic Chromium Coatings Formed on Nanostructured Surfaces By of a Pulsed Laser

Obtain metallic chromium (Cr0) deposits by trivalent chromium in aqueous solution have some disadvantages respect to hexavalent chromium. The obtention of this coatings are not considered feasible to directly from a simple dissolution. The chromium III in aqueous solution presents an octahedral structure [Cr(H2O)6]+3[3], so the baths for the trivalent chrome require complex forming agents. It is also found that is difficult to obtain the same thickness with chromium III as using chromium VI, J. Mcdougall et al[4] report that it is difficult to obtain deposits greater than 2 µm from trivalent chromium, attributed to microstructural differences, causing the properties of the chromium coatings be diminished compared with the hexavalent chromium. A form to controlled the phenomena associated with the nucleation of the trivalent chromium electrolytic deposits is nanostructuring the surface sustrate where the electrodeposit is formed. This can do by pulsed laser-induced phenomenon change microstructure of the bulk. Some authors have reported significant improvements using treatments earlier of coats by pulsed lasers (femtosecond) [5][6][7]. The optimized characteristics reported are: Better Adherence, friction coefficients lower, even the nucleation type can be epitaxial. Therefore, in the present project proposes electrochemical characterization by polarization curves, electrochemical impedance spectroscopy and cyclic voltammetry for substrates of 1008 carbon steel polished and nanostructured by a pulsed laser with pulse ultra-fast. Also structural and morphologic by scanning electron microscopy, X-ray diffraction, etc., Chronoamperometry was used for analyzed the nucleation phenomena on substrates polished and nanostructured materials. [1] S. G. O. J., “Obtención de un Recubrimiento de Cromo Decorativo a Partir de Soluciones de Cromo Trivalente,” Ing. E Investig., vol. 26, pp. 75–83, 2006. [2] D. L. Snyder, “Decorative chromium plating basics,” Met. Finish., vol. 110, no. 2, pp. 14–21, 2012. [3] H. Chun et al., “Molecular and Electronic Structure of Octahedral o -Aminophenolato and o -Iminobenzosemiquinonato Complexes of V ( V ), Cr ( III ), Fe ( III ), and Co ( III ). Experimental Determination of Oxidation Levels of Ligands and Metal Ions,” no. V, pp. 4157–4166, 2001. [4] J. Mcdougall and S. Ma, “Chromium electrodeposition using a chromium ( III ) glycine complex,” vol. 28, 1998. [5] C. Yao et al., “The influence of femtosecond laser repetition rates and pulse numbers on the formation of micro/nano structures on stainless steel,” J. Alloys Compd., vol. 722, pp. 235–241, 2017. [6] X. Chen, Q. Yan, and Q. Ma, “Applied Surface Science Influence of the laser pre-quenched substrate on an electroplated chromium coating / steel substrate,” Appl. Surf. Sci., vol. 405, pp. 273–279, 2017. [7] P. Zhang, L. Chen, J. Chen, and Y. Tu, “Material removal effect of microchannel processing by femtosecond laser,” Opt. Lasers Eng., vol. 98, no. June, pp. 69–75, 2017.

Assessment of the impact of onsite sanitary sewage system and agricultural wastes on groundwater quality in Ikem and its environs, south-eastern Nigeria

ABSTRACTPhysicochemical, multivariate, and bacteriological analyses were integrated to assess the impact of onsite sanitary sewage and agricultural waste on groundwater quality in Ikem and its environs. Results of the physicochemical analysis suggest that groundwater samples in the study area are acidic, with very few samples having electrical conductivity and total dissolved solids above WHO standard for drinking water. The abundance of the major ions are in the following order: Ca2+˃Mg2+˃K+˃Na+˃ Cl− = PO42- ˃NO3−˃HCO3−˃SO42-. Fifty-five percent of the stiff plot shows Ca2+ – Cl− water type and 45% of the stiff shows Na++ K+ – Cl− water type. The dominant hydrochemical facies in the study area are Ca2+–Mg2+–Cl−SO42- (83%) and Na++ K+ and SO42- + Cl− (17%). Durov and Piper diagrams illustrated that simple mineral dissolution and ion exchange processes are mainly responsible for variation in the hydrogeochemistry. Bacteriological analysis shows that the groundwater is contaminated with faecal waste. The principal component analysis, correlation, and cluster analysis reflect Faecal matter contamination through onsite sanitary sewage system, leaching of agricultural waste into the groundwater and weathering and dissolution of host rocks. Groundwater flow direction is local and controlled by topographic highs, weathering and fracturing of the host rock in the study area.

Electrochemical and Electronic Properties of Transparent Coating from Highly Solution Processable Graphene Using Block Copolymer Supramolecular Assembly: Application toward Metal Ion Sensing and Resistive Switching Memory.

Here, we have discussed the preparation of a highly solution processable graphene from a novel supramolecular assembly consisting of block copolymer polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) and pyrenebutyric acid (PBA)-modified reduced graphene oxide (RGO). The PBA molecules anchored on the graphene surface form supramolecules with PS-b-P4VP through H-bonding between the carboxylic acid group of 1-pyrenebutyric acid and the pyridine ring of P4VP. The formation of a supramolecular assembly results in a highly stable solution of reduced graphene oxide in common organic solvents, such as 1,4-dioxane and chloroform. Highly transparent and mechanically stable thin films can be deposited from these supramolecular assemblies on a relatively smooth surface of different substrates such as silicon wafer, glass, indium tin oxide, and flexible polymer substrates like poly(ethylene terephthalate). The graphene surface modifier (PBA) can be selectively removed from the thin film of the hybrid material by simple dissolution, resulting in a porous structure. Hybrid thin films of around 50 nm thickness exhibit interesting electrochemical properties with an areal capacitance value of 17.73 μF/cm2 at a current density of 2.66 μA/cm2 and good electrochemical stability. The pendent P4VP chains present in the composite thin film were further exploited for electrochemical detection of metal ions. The electrical measurement of the thin film sandwich structure of the composite shows a bipolar resistive switching memory with hysteresis-like current–voltage characteristics and electrical bistability. The OFF state shows ohmic conduction at a lower voltage and trap-free space-charge-limited current (SCLC) conduction at high voltage, whereas the ON state conduction is controlled by ohmic at low bias voltage, trap-free SCLC at moderate voltage, and tarp-assisted SCLC at high voltage.

Production of meloxicam suspension using pulsed laser ablation in liquid (PLAL) technique

Organic particles in the micrometer/nanometer size range can find applications in various fields. Unfortunately their production is not a straightforward task for a number of materials. In the present work the production of meloxicam particles in the micrometer range was aimed with the help of pulsed laser ablation in liquid environment (PLAL). Targets pressed from crystalline meloxicam powder were placed in distilled water and irradiated with a focused beam of a frequency doubled (532 nm) nanosecond Nd:YAG laser at 4.2–9.4 J cm−2 fluence. Morphological investigation showed that the produced suspension contained particles in the ~100 nm to 10 µm size range (1.0–2.0 µm on average), which is about 10 times smaller than the size of the initial material. FTIR spectroscopic investigations demonstrated that the chemical composition was preserved, while x-ray diffraction and calorimetric measurements indicated partial amorphization of meloxicam during the process. The overall results suggest that the particles are mostly produced by the fragmentation of the pressed target by the recoil forces induced by the laser pulse. Long period sedimentation tests of the suspension combined with UV–vis spectroscopic analysis showed that by the method of PLAL a greater fraction of the poorly water soluble meloxicam could be dispersed and dissolved in water in a pharmaceutically preferred formation than by simple dissolution of it.

TiO2‐Graphene Nanocomposites for Effective Photocatalytic Degradation of Rhodamine‐B Dye

AbstractThe hazardous Rhodamine‐B dye is photocatalytically degraded by anatase TiO2 and its graphene nanocomposites. These are prepared by a simple electrochemical anodic dissolution of pure titanium in graphene oxide solution, here particle size is tuned by current variation. The structural, morphological and optical properties of these composites are studied by X‐ ray diffraction, UV‐visible spectroscopy, field emission SEM, high resolution TEM and XPS. The photocatalytic activity of Rhodamine‐B in water is studied with visible and UV light irradiation. A significant degradation is observed with 1 wt% of reduced graphene oxide with TiO2 nanoparticles. The stability and reproducibility are tested by recycling the catalyst for more than five times. The results are interpreted in terms of energy band alignment of TiO2‐ graphene interface with respect to energy levels of Rhodamine‐B molecule through water redox potentials. The present work demonstrates that these composites are novel and cost effective in photocatalytic degradation of Rhodamine‐B and hence are potential materials for environmental remedy.

Square wave voltammetry at carbon paste electrode modified with surfactant for alpha tocopheryl acetate determination in cosmetics

The aim of this study was describe electrochemical properties of a carbon paste electrode (CPE) bulk modified with 30% (w/w) surfactant sodium dodecyl sulphate (CPE/SDS) and demonstrates its application in the determination of α‑tocopheryl acetate (α‑TAc), known as vitamin E acetate, in selected cosmetic products, especially body creams. In addition to anionic SDS, cationic hexadecylpyridinium chloride monohydrate (CPC) was also tested as possible modifier. It was found that selection of surfactant type and its content significantly affect an electrical conductivity and mechanical stability of these heterogeneous electroanalytical sensors in pure organic solvents. Under this study, it was found that CPC is a totally inappropriate mediator due to very high backgroundcurrent. Together with other lipophilic vitamins characterized by antioxidant activity (dominantly retionoids), this completely synthetic substance is widely used as significant cosmetic additive due its preservative properties. Monitoring of its content in cosmetic products is usually performed by high‑performance liquid chromatography (HPLC) with UV detection. This standard analytical protocol is always burdened with the complex and time‑consuming preparation of the sample before analysis. For that reason, robust and simple electroanalytical method based on anodic oxidation of the α‑TAc at CPE/SDS by square wave voltammetry (SWV) performed in pure organic electrolyte (99.8% acetonitrile containing 0.1 mol·L‑1 LiClO4) was developed. Moreover, simple dissolution of sample in supporting electrolyte using ultrasonic bath and subsequent filtering through a stacked filter included all the necessary procedures for sample preparation. The linear range from 0.1 to 1.2 mmol·L‑1and limit of detection 37 µmol·L‑1 were found at pulse amplitude 10 mV and frequency 10 Hz as optimum. In analysis of selected cosmetics, the developed electroanalytical method was not validated using comparison with standard HPLC. At least, the recovery was verified by analysis of model sample and value 95.8% was calculated.

Novel heat-resistant and soluble poly(amide–ether)/zinc oxide nanocomposites: synthesis, characterization and computational study

Novel heat-resistant poly(amide–ether)/zinc oxide nanocomposites containing two different types of ZnO nanoparticles were successfully prepared by a solution intercalation technique. A new poly(amide–ether) (PAE) as a source of polymeric matrix was synthesized by direct polycondensation reaction of new diamine containing 1,3,4-oxadiazole and biphenyl groups with 4,4′-(butane-1,4-diylbis(oxy))dibenzoic acid in a medium consisting of N-methyl-2-pyrrolidone,triphenyl phosphite, calcium chloride, and pyridine. Fourier-transform infrared (FTIR), nuclear magnetic resonance (1H NMR), and UV–Vis technique were used for characterization of as-synthesized PAE. The synthesized PAE revealed good solubility in dipolar aprotic solvents at room temperature and the inherent viscosity of the PAE in DMF at a concentration of 0.01 g dL−1 at 25 °C was 0.34 dL/g. Improved solubility was attributed to the presence of flexible ether linkage in the polyamide backbones that reduce the chain–chain interaction and enhance solubility by penetrating solvent molecules into the polyamide chains. The structural and electronic properties of PAE units were studied by ab initio density functional theory method using the B3LYP/6-31G (d) level of theory. Due to incorporation of biphenyl group as an electron donor on the 1,3,4-oxadiazole ring in the structure of PAE, the highest occupied molecular orbitals (HOMO) are localized mainly on biphenyl group. The calculated absorption spectrum of the studied PAE exhibited the maximum absorption wavelength which corresponds to the electronic transition from the HOMO-1 to LUMO with 92% contribution. Zinc oxide nanoparticles were synthesized by a direct precipitation method from zinc nitrate solution and were modified with 1-methyl-3-(trimethoxysilylpropyl) imidazolium chloride. The PAE/ZnO nanocomposite films were prepared by simple dissolution technique using 3 wt% of ZnO nanoparticles and modified ZnO nanoparticles. The morphology, crystalline phase, and thermal stability of the resultant materials were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), thermal gravimetric analysis (TGA), and FTIR techniques. The FE-SEM analysis showed better dispersion of ZnO@ImCl nanoparticles within the poly(amide–ether) matrix in comparison with ZnO nanoparticles, which arises from high interactions between ZnO@ImCl and the PAE chains. Thermogravimetric analysis results indicated improving on thermal properties of the poly(amide–ether) nanocomposites as compared with the neat poly(amide–ether). The incorporation of functional ZnO@ImCl nanoparticles could further improve the thermal properties of poly(amide–ether). The high interaction between poly(amide–ether) and ZnO@ImCl nanoparticles, the presence of oxadiazole, ether, amide and imidazole content of the ZnO@ImCl nanoparticles seem to be responsible for the improvement of the thermal properties. Furthermore, the presence of oxadiazole, ether, amide and bulky biphenyl groups in the poly(amide–ether) backbone increased the solubility in organic solvents.

Groundwater Monitoring in the Gneisso-Basaltic Fractured Rock Aquiferous Formations of Kumba, Southwest Region Cameroon: Seasonal Variations in the Aqueous Geochemistry and Water Quality

The objective was to determine and monitor seasonal changes during four hydrological seasons: Wet season (September), Wetdry season (December), Dry season (March) and Drywet season (June) in the groundwater aqueous geochemistry and its domestic-agro-industrial quality using physicochemical parameters and hydrogeochemical tools: Temperature, Electrical Conductivity EC, pH, Total dissolved solids TDS, Ionic ratios, Gibbs diagrams, Piper diagrams Durov diagrams, total hardness HT, Water quality index WQI, Sodium adsorption ratio SAR, Percent Sodium %Na, Kelly’s Ratio KR, permeability index PI, Magnesium adsorption ratio MAR, Residual sodium carbonate RSC and Wilcox diagram. Field physicochemical parameters ranged from: Wet season; pH 3.9 - 6.9; Temperature, 23.3°C - 29.1°C; EC, 10 - 1900 μS/cm; TDS, 6.7 - 1273 mg/L; Wetdry, pH, 5.7 - 11.7; Temperature, 23.6°C - 28.3°C; EC, 1 - 1099 μS/cm, TDS, 0.67 - 736.33 mg/L; Dry pH, 5.7 - 13.1; Temperature, 26.3°C - 30.2°C; EC, 12 - 770 μS/cm, TDS, 8.04 - 515.9 mg/L and Drywet, pH, 4 - 7.4; Temperature, 25.8°C - 30.7°C; EC, 10 - 1220 μS/cm, TDS, 6.7 - 817.4 mg/L. Seventy-two groundwater samples, 18 per season were analysed. All ionic concentrations fell below acceptable World Health Organization guidelines in all seasons. The sequence of abundance of major ions are; Wet, Ca+ > Mg2+ > Na+ = K+ > NH4+, HCO3? > Cl? > NO3? > SO42? > HPO42?; Wetdry Ca+ > K+ > Mg2+ > Na+ > NH4+, HCO3? > Cl? > SO42? > NO3? > HPO42?; Dry Ca+ > K+ > Mg2+ > Na+ > NH4+, HCO3? > Cl?> NO3? > SO42? > HPO42?; Drywet NH4+ > Ca+ > K+ > Mg2+ > Na+; Cl? > HCO3? > NO3? > SO42? > HPO42?. Groundwater ionic content was due to rock weathering and ion exchange reactions. CaSO4 is the dominant water type in Wet and Wetdry seasons; followed by CaHCO3, Na + K-Cl Wet, CaSO4 and CaHCO3 Wetdry; MgCl Dry and Drywet followed by CaCl, CaHCO3 Dry and CaSO4, CaHCO3 Dry-Wet. The dominant hydrogeochemical facies are Ca-Mg-Cl-SO4 followed by Na-K-SO4 Wet and Ca-Mg-HCO3? in all other seasons. Ion exchange, Simple dissolution and uncommon dissolution are the processes determining groundwater character. The water quality indices; WQI, HT, SAR, %Na, KR, PI, MAR,RSC and Wilcox diagrams, indicate that groundwater in Kumba is 80% - 100% excellent during the Drywet &Wet seasons, 5% - 10% unsuitable during the Wetdry & Dry seasons for domestic use while being excellent-good for Agro-Industrial uses in all other seasons. Physicochemical parameters in some areas exceeded permissible limits for drinking. All hydrogeochemical parameters vary with seasons and these variations show the impact of annual cycles of seasonal changes on the aqueous geochemistry of groundwater in Kumba.

Fabrication of truly 3D microfluidic channel using 3D-printed soluble mold.

The field of complex microfluidic channels is rapidly expanding toward channels with variable cross-sections (i.e., beyond simple rounded channels with a constant diameter), as well as channels whose trajectory can be outside of a single plane. This paper introduces the use of three-dimensional (3D) printed soluble wax as cast molds for rapid fabrication of truly arbitrary microfluidic polydimethylsiloxane (PDMS) channels that are not achieved through typical soft lithography. The molds are printed directly from computer-aided design files, followed by simple dissolution using a solvent after molding PDMS, making rapid prototyping of microfluidic devices possible in hours. As part of the fabrication method, the solubility of several build materials in solvents and their effect on PDMS were investigated to remove the 3D-printed molds from inside the replicated PDMS microfluidic channels without damage. Technology limits, including surface roughness and resolution by comparing the designed channels with fabricated cylindrical channels with various diameters, are also characterized. We reproduced a 3D image of an actual human cerebral artery as cerebral artery-shaped PDMS channels with a diameter of 240 μm to prove the developed fabrication technique. It was confirmed that the fabricated vascular channels were free from any leakage by observing the fluorescence fluid fill.

Biodissolution and Cellular Response to MoO3 Nanoribbons and a New Framework for Early Hazard Screening for 2D Materials.

Two-dimensional (2D) materials are a broad class of synthetic ultra-thin sheet-like solids whose rapid pace of development motivates systematic study of their biological effects and safe design. A challenge for this effort is the large number of new materials and their chemical diversity. Recent work suggests that many 2D materials will be thermodynamically unstable and thus non-persistent in biological environments. Such information could inform and accelerate safety assessment, but experimental data to confirm the thermodynamic predictions is lacking. Here we propose a framework for early hazard screening of nanosheet materials based on biodissolution studies in reactive media, specially chosen for each material to match chemically feasible degradation pathways. Simple dissolution and in vitro tests allow grouping of nanosheet materials into four classes: A, potentially biopersistent; B: slowly degradable (>24-48 hours); C, biosoluble with potentially hazardous degradation products; and D, biosoluble with low-hazard degradation products. The proposed framework is demonstrated through an experimental case study on MoO3 nanoribbons, which have a dual 2D / 1D morphology and have been reported to be stable in aqueous stock solutions. The nanoribbons are shown to undergo rapid dissolution in biological simulant fluids and in cell culture, where they elicit no adverse responses up to 100μg ml-1 dose. These results place MoO3 nanoribbons in Class D, and assigns them a low priority for further nanotoxicology testing. We anticipate use of this framework could accelerate the risk assessment for the large set of new powdered 2D nanosheet materials, and promote their safe design and commercialization.

Hydrogeochemical Model and Water Quality of Groundwater in the Granito-Basaltic Fractured Rock Aquiferous Formations in Bafoussam, West Region-Cameroon

This study determined the hydrogeochemical model of groundwater and groundwater domestic-agro-industrial quality in Bafoussam using hydrogeochemical tools and physicochemical parameters: Ionic ratios, Gibbs diagrams, Piper diagrams, Durov diagrams and water quality indices. From physicochemical parameters; pH ranged from, 4.47 - 7.84; EC, 10 - 820 μS/cm; Temperature, 22.3°C - 29.5°C and TDS, 6.7 - 549.4 mg/L. The major ions fell below WHO acceptable limits. The sequences of major ionic abundance are: Ca2+ > Mg2+ > K+ > Na+ > NH+4, HCO-3 > Cl- > SO2-4 > NO3 > HPO2-4. Recharge by atmospheric precipitation, ion-exchange and simple dissolution processes are responsible for groundwater character, ionic content resulted from ion exchange and rock-weathering. Water types are Ca-HCO3 and Ca-Cl Hydrogeochemical facies are Ca-Mg-Cl-SO4 and Ca-Mg-HCO3. Domestic water quality was determined by use of pH, electrical Conductivity EC, total dissolved solids TDS, total Hardness HT and water quality index WQI. WQI values ranged from 0 - 42.09 and HT 67.89 - 339.01 indicating that water is of good domestic quality. Agro-industrial suitability of groundwater was determined using, sodium adsorption ratio SAR, permeability index PI, Magnesium adsorption ratio MAR, percent sodium %Na, Kelly’s ratio KR and Residual sodium carbonate RSC and Wilcox diagram; From irrigational water suitability parameters, SAR values ranged from 0.01 - 0 05; %Na 3.69 - 15.50; KR 0.005 - 0.023; PI 1.04 - 67.98; MAR 2.89 - 55.27; RSC -5.22 to -0.44 and Wilcox diagram indicate that inorganic groundwater content in the study area is excellent-good for irrigation; this is of significance since Bafoussam a major agroindustrial zone in Cameroon and Central Africa is in the process of developing large scaled irrigation based agricultural projects dependent on use of surface and groundwater. Recharge from precipitation exchanges ions with the weathered country rocks and mixes with regional flow in a generally south-east north-westerly direction by piston flow in the granito-basaltic aquiferous formations in Bafoussam. There is need for detailed studies to determine aquifer characteristics: permeability, transmissivity and storativity, vertical-lateral regional extent of aquifer boundaries, groundwater pollution potentials for biological, organic and trace metals.

Direct Transmission Electron Microscopy Visualization of the Cement Reaction by Colloidal Aggregation of Fumed Silica

Unlike other solidified materials, concrete has an internal structure that contains small pores that vary in size from several nanometers to the submicrometer range. These pores govern the strength of the material and hence the lifetime of concrete buildings. The size of the pores is governed by the presence of calcium silicate hydrate (CaO·2SiO2·4H2O, C–S–H). To identify how the pore size is determined during the concretion process, we used transmission electron microscopy to examine the early solidification of a simplified reaction system consisting of silica, portlandite [Ca(OH)2, CH], and water. The silica particles, used to suppress the degradation of concrete, expanded and, consequently, embedded the pores through hydration before C–S–H was formed, contrary to the predicted decrease in pore size by C–S–H formation after simple dissolution of silica. Visualization of this type of solidification process should permit improvement in the mechanical strength of concrete.

The artificial membrane insert system as predictive tool for formulation performance evaluation

In view of the increasing interest of pharmaceutical companies for cell- and tissue-free models to implement permeation into formulation testing, this study explored the capability of an artificial membrane insert system (AMI-system) as predictive tool to evaluate the performance of absorption-enabling formulations. Firstly, to explore the usefulness of the AMI-system in supersaturation assessment, permeation was monitored after induction of different degrees of loviride supersaturation. Secondly, to explore the usefulness of the AMI-system in formulation evaluation, a two-stage dissolution test was performed prior to permeation assessment. Different case examples were selected based on the availability of in vivo (intraluminal and systemic) data: (i) a suspension of posaconazole (Noxafil®), (ii) a cyclodextrin-based formulation of itraconazole (Sporanox®), and (iii) a micronized (Lipanthyl®) and nanosized (Lipanthylnano®) formulation of fenofibrate. The obtained results demonstrate that the AMI-system is able to capture the impact of loviride supersaturation on permeation. Furthermore, the AMI-system correctly predicted the effects of (i) formulation pH on posaconazole absorption, (ii) dilution on cyclodextrin-based itraconazole absorption, and (iii) food intake on fenofibrate absorption. Based on the applied in vivo/in vitro approach, the AMI-system combined with simple dissolution testing appears to be a time- and cost-effective tool for the early-stage evaluation of absorption-enabling formulations.

Synthesis of an Aluminum Hydroxide Octamer through a Simple Dissolution Method

AbstractMultimeric oxo‐hydroxo Al clusters function as models for common mineral structures and reactions. Cluster research, however, is often slowed by a lack of methods to prepare clusters in pure form and in large amounts. Herein, we report a facile synthesis of the little known cluster Al8(OH)14(H2O)18(SO4)5 (Al8) through a simple dissolution method. We confirm its structure by single‐crystal X‐ray diffraction and show by 27Al NMR spectroscopy, electrospray‐ionization mass spectrometry, and small‐ and wide‐angle X‐ray scattering that it also exists in solution. We speculate that Al8 may form in natural water systems through the dissolution of aluminum‐containing minerals in acidic sulfate solutions, such as those that could result from acid rain or mine drainage. Additionally, the dissolution method produces a discrete Al cluster on a scale suitable for studies and applications in materials science.

Synthesis of an Aluminum Hydroxide Octamer through a Simple Dissolution Method.

Multimeric oxo-hydroxo Al clusters function as models for common mineral structures and reactions. Cluster research, however, is often slowed by a lack of methods to prepare clusters in pure form and in large amounts. Herein, we report a facile synthesis of the little known cluster Al8 (OH)14 (H2 O)18 (SO4 )5 (Al8 ) through a simple dissolution method. We confirm its structure by single-crystal X-ray diffraction and show by 27 Al NMR spectroscopy, electrospray-ionization mass spectrometry, and small- and wide-angle X-ray scattering that it also exists in solution. We speculate that Al8 may form in natural water systems through the dissolution of aluminum-containing minerals in acidic sulfate solutions, such as those that could result from acid rain or mine drainage. Additionally, the dissolution method produces a discrete Al cluster on a scale suitable for studies and applications in materials science.

Study of synergistic effect of cellulose on the enhancement of photocatalytic activity of ZnO

Semiconductor photocatalysts play a major role in photocatalytic process. Zinc oxide (ZnO) is supposed to be a preferred photocatalyst due to its high photosensitivity, mechanical–thermal stability, tunable morphology and non-toxicity. To enhance the photocatalytic activity of ZnO, cellulose/ZnO composite films (CZ films) with snowflake-like ZnO micro/nanoparticles immobilized in cellulose matrix were prepared by a simple dissolution and regeneration of cellulose and subsequently one-step hydrothermal synthesis of ZnO. The immobilization of ZnO was conducive to overcoming the shortcomings of aggregation easily and reclamation difficulty of scattered nanopowders. The obtained CZ films exhibited excellent photocatalytic efficiency (85.3%) to degrade methylene blue with minor amount of ZnO photocatalyst (<6 mg). The experimental results show that a photocatalytic process involving absorption–degradation–desorption was proposed. Notably, the synergistic effects between cellulose film and the supported ZnO via absorption and desorption processes were important to enhance the photocatalytic efficiency. This work provided an effective method to support ZnO photocatalyst and improve the photocatalytic efficiency via a functional substrate.

Isolation of Aramid Nanofibers for High Strength and Toughness Polymer Nanocomposites.

The development of nanoscale reinforcements that can be used to improve the mechanical properties of a polymer remains a challenge due to the long-standing difficulties with exfoliation and dispersion of existing materials. The dissimilar chemical nature of common nanofillers (e.g., carbon nanotubes, graphene) and polymeric matrix materials is the main reason for imperfect filler dispersion and, consequently, low mechanical performance of their composites relative to theoretical predictions. Here, aramid nanofibers that are intrinsically dispersible in many polymers are prepared from commercial aramid fibers (Kevlar) and isolated through a simple, scalable, and low-cost controlled dissolution method. Integration of the aramid nanofibers in an epoxy resin results in nanocomposites with simultaneously improved elastic modulus, strength, and fracture toughness. The improvement of these two mutually exclusive properties of nanocomposites is comparable to the enhancement of widely reported carbon nanotube reinforced nanocomposites but with a cost-effective and more feasible method to achieve uniform and stable dispersion. The results indicate the potential for aramid nanofibers as a new class of reinforcements for polymers.

Geochemistry of rare earth elements in groundwater from different aquifers in the Gboko area, central Benue Trough, Nigeria

Water samples from different aquifers in Gboko area, Lower Benue Trough, Nigeria, were evaluated to determine the quality, hydrochemical facies and the concentrations and fractionation patterns of rare earth elements (REEs) in the groundwater. The results revealed that the groundwater is contaminated with factors emanating from the concentrations of NO3, Cl, Mn, and the TDS (total dissolved solids). Five hydrochemical facies were identified, namely Na + KSO4Cl, Na + KHCO3, MgSO4Cl, and two forms of CaMgHCO3 (viz., Na + KHCO3 and Na + KSO4Cl). Ion exchange leads to the formation of Na + KHCO3 from CaMgHCO3, while reversed ion exchange leads to the formation of Na + KSO4Cl from CaMgHCO3, usually in the presence of saline water conditions. Also, simple dissolution or linear mixing gives rise to CaMgSO4Cl from CaMgHCO3. The results also showed that the contents of REE in the samples range from 1 to 445 ppb, with significant contributions from La, Ce and Nd. The shallow groundwater is predominantly LREE-enriched NASC-normalized patterns. The LREE enrichment is attributed to weathering of host rock minerals, such as phosphate monazite, florencite, and allanite, in an oxic environment, while the HREE enrichment is attributed to processes such as complexation reactions, desorption processes, re-adsorption processes, and chemical weathering in a reducing condition. The groundwater shows positive anomalies for both Ce and Eu. The Ce is controlled by oxidation of Ce3+ to Ce4+, incorporation of Ce into Mn and Fe oxyhydroxides phases, and Eu anomalies by weathering of zircon-rich minerals.