Low Molar Ratio Research Articles

Strength and Microstructure Characteristics of Blended Fly Ash and Ground Granulated Blast Furnace Slag Geopolymer Mortars with Na and K Silicate Solution.

Mineral geopolymer binders can be an attractive and more sustainable alternative to traditional Portland cement materials for special applications. In geopolymer technology the precursor is a source of silicon and aluminium oxides, the second component is an alkaline solution. In the synthesis of geopolymer binders the most commonly used alkaline solution is a mixture of sodium or potassium water glass with sodium or potassium hydroxide or silicate solution with a low molar ratio, which is more convenient and much safer in use. In this paper, we present the influence of sodium or potassium silicate solution on the physical and mechanical properties of fly ash and ground granulated blast furnace slag-based geopolymer mortars. Mercury intrusion porosimetry and microstructural observation allowed for comparing the structure of materials with a different type of alkaline solution. The evolution of compressive and flexural tensile strength with time determined for composites using 10%, 30% and 50% slag contents (referring to fly ash mass) was analysed. The tests were performed after 3, 7, 14 and 28 days. It was observed that, as the amount of slag used increases in the precursor, the strength of the material grows. Mortars with the sodium alkaline solution were characterised by a higher strength at a young age. However, the values of strength 28 days were higher for geopolymers with potassium alkaline solution reaching 75 MPa in compression. Geopolymer mortar microstructure observation indicates a high matrix heterogeneity with numerous microcracks. Matrix defects may be caused by the rapid kinetics of the material binding reaction or shrinkage associated with the drying of the material.

Structural and Functional Changes of Reconstituted High-Density Lipoprotein (HDL) by Incorporation of α-synuclein: A Potent Antioxidant and Anti-Glycation Activity of α-synuclein and apoA-I in HDL at High Molar Ratio of α-synuclein.

α-synuclein (α-syn) is a major culprit of Parkinson’s disease (PD), although lipoprotein metabolism is very important in the pathogenesis of PD. α-syn was expressed and purified using the pET30a expression vector from an E. coli expression system to elucidate the physiological effects of α-syn on lipoprotein metabolism. The human α-syn protein (140 amino acids) with His-tag (8 amino acids) was expressed and purified to at least 95% purity. Isoelectric focusing gel electrophoresis showed that the isoelectric point (pI) of α-syn and apoA-I were pI = 4.5 and pI = 6.4, respectively. The lipid-free α-syn showed almost no phospholipid-binding ability, while apoA-I showed rapid binding ability with a half-time (T1/2) = 8 ± 0.7 min. The α-syn and apoA-I could be incorporated into the reconstituted HDL (rHDL, molar ratio 95:5:1:1, palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC):cholesterol:apoA-I:α-syn with the production of larger particles (92 Å) than apoA-I-rHDL (86 and 78 Å) and α-syn-rHDL (65 Å). An rHDL containing both apoA-I and α-syn showed lower α-helicity around 45% with a red shift of the Trp wavelength maximum fluorescence (WMF) from 339 nm, while apoA-I-HDL showed 76% α-helicity and 337 nm of WMF. The denaturation by urea addition showed that the incorporation of α-syn in rHDL caused a larger increase in the WMF than apoA-I-rHDL, suggesting that the destabilization of the secondary structure of apoA-I by the addition of α-syn. On the other hand, the addition of α-syn induced two-times higher resistance to rHDL glycation at apoA-I:α-syn molar ratios of 1:1 and 1:2. Interestingly, low α-syn in rHDL concentrations, molar ratio of 1:0.5 (apoA-I:α-syn), did not prevent glycation with more multimerization of apoA-I. In the lipid-free and lipid-bound state, α-syn showed more potent antioxidant activity than apoA-I against cupric ion-mediated LDL oxidation. On the other hand, microinjection of α-syn (final 2 μM) resulted in 10% less survival of zebrafish embryos than apoA-I. A subcutaneous injection of α-syn (final 34 μM) resulted in less tail fin regeneration than apoA-I. Interestingly, incorporation of α-syn at a low molar ratio (apoA-I:α-syn, 1:0.5) in rHDL resulted destabilization of the secondary structure and impairment of apoA-I functionality via more oxidation and glycation. However, at a higher molar ratio of α-syn in rHDL (apoA-I:α-syn = 1:1 or 1:2) exhibited potent antioxidant and anti-glycation activity without aggregation. In conclusion, there might be a critical concentration of α-syn and apoA-I in HDL-like complex to prevent the aggregation of apoA-I via structural and functional enhancement.

Role of Water in the Lyotropic Liquid Crystalline Mesophase of Lithium Salts and Non-ionic Surfactants.

The lyotropic liquid crystalline (LLC) mesophase forms upon evaporation of water from aqueous solutions of LiX salts (X is Cl-, Br-, NO3-, or SCN-) and a surfactant [C12H25(OCH2CH2)10OH, abbreviated as C12E10]. The LiX/C12E10/H2O aqueous solutions have been monitored (during evaporation of their excess water to obtain stable LLC mesophases) by gravimetric, spectroscopic, and conductivity measurements to elucidate the role of water in these mesophases. The water/salt molar ratio in stable mesophases changes from 1.5 to 8.0, depending on the counteranion of the salt and the ambient humidity of the laboratory. The LiX/C12E10/H2O LLC mesophases lose water at lower humidity levels and absorb water at higher humidity levels. The LiCl-containing mesophase holds as few as four structural water molecules per LiCl, whereas the LiNO3 mesophase holds 1.5 waters per salt (least among those assessed). This ratio strongly depends on the atmospheric humidity level; the water/LiX mole ratio increases by 0.08 ± 0.01 H2O in the LLC mesophases per percent humidity unit. Surprisingly, the LLC mesophases are stable (no salt leaching) in broad humidity (10-85%) and salt/surfactant mole ratio (2-10 LiX/C12E10) ranges. Attenuated total reflectance Fourier transform infrared spectroscopic data show that the water molecules in the mesophase interact with salt species more strongly in the LiCl mesophase and more weakly in the case of the nitrate ion, which is evident by the shift of the O-H stretching band of water. The O-H stretching peak position in the mesophases decreases in the order νLiCl > νLiBr > νLiSCN > νLiNO3 and accords well with the H2O/LiX mole ratio. The conductivity of the LLC mesophase also responds to the amount of water as well as the nature of the counteranion (X-). The conductivity decreases in the order σLiCl > σLiBr > σLiNO3 > σLiSCN at low salt mole ratios and in the order σLiBr > σLiCl > σLiNO3 > σLiSCN at higher ratios due to structural changes in the mesophase.

Synthesis and characterization of mesoporous gamma-alumina by glucose as soft-template for molybdenum-99 adsorption: high and low molar ratio of water to aluminium isopropoxide effect

The mesoporous gamma-alumina is a good material for metal adsorption. Its textural properties are excellent, mainly for molybdenum-99 radioisotopes adsorption as part of 99Mo/99mTc generator in nuclear medicine. In this work, we have prepared mesoporous gamma-alumina by sol-gel treatment in the presence of glucose as a soft template. The molar ratio of reactant (water: aluminium isopropoxide(AIP)) was applied in the high and low ratios (150:1 and 25:1). The resulted mesoporous gamma-alumina was investigated using characterization analysis of X-ray diffraction, Nitrogen adsorption-desorption, and FTIR. The results indicate that the mesoporous gamma-alumina in the high molar ratio of water to AIP had a higher surface area and better crystallinity than the low molar ratio of reactants. Furthermore, in the Mo adsorption test, the mesoporous gamma-alumina with the high molar ratio posed a higher Mo adsorption capacity up to 55.69 mg Mo g−1 adsorbent. In the future, the molar ratio of reactants should be tuned in the range of around 150:1 to obtain the optimal Mo adsorption capacities of the resulted mesoporous gamma-alumina using the glucose template.

Morphology-tunable synthesis and formation mechanism of SnO2 particles and their application in Ag–SnO2 electrical contact materials

SnO2 powders with four distinct morphologies of prismoids, hollow rhomboidal tubes, solid rhomboidal rods, and needles have been prepared through morphology-conserved transformation from SnC2O4 precursors. The SnC2O4 precursors were synthesized by a facile oxalate precipitation method. A controllable periodic bond chain (PBC) growth was found to be critical for the formation of these SnC2O4 samples. In the case of forward titration, SnC2O4 prismoids were generated because the formed Sn3O(OH)2SO4 was attached on {1- 01} polar facets and inhibited the PBC growth along the c axis. By contrast, in the case of reverse titration, SnC2O4 samples preferably formed one-dimensional shapes. Dissolution and ripening were observed during the formation of hollow tubes in the case of low molar ratio of Sn2+ to C2O42−. Further, the formation of SnC2O4 needles was ascribed to the selective coordination of polyvinylpyrrolidone (PVP) on the side surface. The as-prepared SnO2 powders were used as reinforcement of Ag–SnO2 electrical contact materials, and a good adhesion was observed at the Ag (111)/SnO2 (200) interface. Further, the characterization results revealed that the sample reinforced by SnO2 tubes (with one-dimensional shape and hollow structure) had the lowest degradation rate under cathode arc erosion, which might be attributed to its good resistance to the dual action (heat and force) of cathode arc.

Stimuli-Responsive Nucleotide-Amino Acid Hybrid Supramolecular Hydrogels.

The ability to assemble chemically different gelator molecules into complex supramolecular hydrogels provides excellent opportunities to construct functional soft materials. Herein, we demonstrate the formation of hybrid nucleotide–amino acid supramolecular hydrogels. These are generated by the silver ion (Ag+)-triggered formation of silver–guanosine monophosphate (GMP) dimers, which undergo self-assembly through non-covalent interactions to produce nanofilaments. This process results in a concomitant pH reduction due to the abstraction of a proton from the guanine residue, which triggers the in situ gelation of a pH-sensitive amino acid, N-fluorenylmethyloxycarbonyl tyrosine (FY), to form nucleotide–amino acid hybrid hydrogels. Alterations in the supramolecular structures due to changes in the assembly process are observed, with the molar ratio of Ag:GMP:FY affecting the assembly kinetics, and the resulting supramolecular organisation and mechanical properties of the hydrogels. Higher Ag:GMP stoichiometries result in almost instantaneous gelation with non-orthogonal assembly of the gelators, while at lower molar ratios, orthogonal assembly is observed. Significantly, by increasing the pH as an external stimulus, nanofilaments comprising FY can be selectively disassembled from the hybrid hydrogels. Our results demonstrate a simple approach for the construction of multicomponent stimuli-responsive supramolecular hydrogels with adaptable network and mechanical properties.

A high-productivity process for mass-producing Fe3O4 nanoparticles by co-precipitation in a rotating packed bed

Fe3O4 nanoparticles were mass-produced using a rotating packed bed (RPB) and the role of stoichiometric ratio and the effects of the FeCl2 and FeCl3 concentrations, aging temperature, and Fe2+ and Fe3+ sources on the characteristics of the obtained Fe3O4 nanoparticles were examined. A high-productivity process for mass-producing Fe3O4 nanoparticles with a rate of approximately 23 kg/day was developed with an FeSO4 concentration of 0.15 mol/L, an FeCl3 concentration of 0.3 mol/L, an NaOH concentration of 1.2 mol/L, a production temperature of 25 °C, an aging temperature of 25 °C, a rotational speed of 1800 rpm, a flow rate of aqueous FeSO4/FeCl3 of 0.5 L/min, and a flow rate of aqueous NaOH of 0.5 L/min. The thus mass-produced Fe3O4 nanoparticles had a mean diameter of 8.4 nm and exhibited superparamagnetism with a saturation magnetization of 61 emu/g. Since the RPB provides excellent micromixing and overcomes the difficulty of mass-production that is associated with traditional co-precipitation in a batch process, Fe3O4 nanoparticles that are mass-produced in an RPB are smaller than Fe3O4 nanoparticles that are batch-produced in a batch reactor, and so have a greater adsorption capacity to remove Reactive Red 2 from water. The results in this work demonstrate that an RPB can mass-produce Fe3O4 nanoparticles at a production temperature of 25 °C and an aging temperature of 25 °C with a low molar ratio of OH− to Fe2+ (8:1). Accordingly, a high-productivity process for mass-producing Fe3O4 nanoparticles can be implemented using an RPB with co-precipitation.

Intercalation of a Cationic Cyanine Dye Assisted by Anionic Surfactants within Mg-Al Layered Double Hydroxide.

An original route for the intercalation of a 1,1′-diethyl-2,2′-cyanine iodide (PIC) cationic dye, through the use of anionic surfactants as vector/carrier phases, within Mg–Al layered double hydroxide (LDH) was investigated. From the data acquired from complementary techniques (X-ray diffraction, infrared and UV–visible spectroscopies, thermogravimetry, and fluorimetry), it appears that both the intercalation and aggregation states of the cationic dye within the internal structure of LDH mainly depend on both the surfactant state (monomer form or spherical micelle) and its amount. The intercalation of PIC at a low molar ratio to the anionic surfactant leads to the formation of J-aggregates with singular fluorescence properties that mainly depend on the nature of the anionic surfactant used for the co-intercalation process. The results obtained in this study open new routes for the intercalation of cationic species, assisted by anionic surfactants, within LDHs.

Simultaneous Improvement of Formaldehyde Emission and Adhesion of Medium-Density Fiberboard Bonded with Low-Molar Ratio Urea-Formaldehyde Resins Modified with Nanoclay

In wood-based composite panels, low-molar ratio (LMR) urea-formaldehyde (UF) resins usually result in reduced formaldehyde emission (FE) at the expense of poor adhesion. However, the FE and adhesion of medium-density fiberboard (MDF) bonded with LMR UF resins were both improved in this study. The modified LMR UF resins with transition metal ion-modified bentonite (TMI-BNT) nanoclay simultaneously improved the FE and adhesion of MDF panels. The modified LMR UF resins with 5% TMI-BNT resulted in a 37.1% FE reduction and 102.6% increase in the internal bonding (IB) strength of MDF panels. Furthermore, thickness swelling and water absorption also significantly decreased to 13.0% and 24.9%, respectively. These results imply that TMI-BNT modification of LMR UF resins could enhance the formation of a three-dimensional network rather than crystalline domains, resulting in improved cohesion.

Optimization of lipid nanoparticles for the delivery of nebulized therapeutic mRNA to the lungs.

Lipid nanoparticles (LNPs) for the efficient delivery of drugs need to be designed for the particular administration route and type of drug. Here we report the design of LNPs for the efficient delivery of therapeutic RNAs to the lung via nebulization. We optimized the composition, molar ratios and structure of LNPs made of lipids, neutral or cationic helper lipids and poly(ethylene glycol) (PEG) by evaluating the performance of LNPs belonging to six clusters occupying extremes in chemical space, and then pooling the lead clusters and expanding their diversity. We found that a low (high) molar ratio of PEG improves the performance of LNPs with neutral (cationic) helper lipids, an identified and optimal LNP for low-dose messenger RNA delivery. Nebulized delivery of an mRNA encoding a broadly neutralizing antibody targeting haemagglutinin via the optimized LNP protected mice from a lethal challenge of the H1N1 subtype of influenza A virus, and delivered mRNA more efficiently than LNPs previously optimized for systemic delivery. A cluster approach to LNP design may facilitate the optimization of LNPs for other administration routes and therapeutics.

Stable magneto-fluorescent gadolinium-doped AgInS2 core quantum dots (QDs) with enhanced photoluminescence properties

Gadolinium paramagnetic ion-doped quantum dots (QDs) have been recognized as attractive materials for fluorescence and magnetic field-driven water-based applications. However, the current Gd-based magneto-fluorescent materials exhibit low magnetic loading (low Gd molar ratio) and poor fluorescence characteristics (loss of photoluminescence at higher Gd loading), thus limiting their efficiency and applications. This paper demonstrates the facile synthesis of the citrate-capped gadolinium-doped AgInS2 QDs with stable magnetic properties and enhanced photoluminescence characteristics over a long period of time. To the best of our knowledge, the excellent fluorescent magnetic AgInS2 QDs with Gd’s molar ratio of up to 20 is being realized for the first time. The materials were characterized using standard optical and microscopic techniques. The fluorescence properties of the nanomaterials were enhanced over six months of storage without loss of the magnetic properties. The high Gd-loading makes the as-synthesized materials attractive for sensing and removal of pollutants from the water environment.

Physicochemical nature of sodium dodecyl sulfate interactions with bovine serum albumin revealed by interdisciplinary approaches

To rigorously characterize the interactions of sodium dodecyl sulfate (SDS) with bovine serum albumin (BSA) a set of experimental methods, namely isothermal titration calorimetry, conductometric titration, steady-state fluorescence spectroscopy, differential scanning calorimetry and circular dichroism spectroscopy, supported by in silico analysis have been applied. The influence of pH and temperature on the binding mode has been revealed. At a low molar ratio of SDS to BSA up to ca. 16:1, there are at least two structurally distinct binding sites in BSA. The formation of SDS-BSA complexes is an enthalpy-driven process in which the van der Waals interactions play a crucial role. The first binding site, located close to the Trp-134 residue within the sub-domain IA, is pH-independent and binds two molecules of SDS per one molecule of BSA whereas the total number of SDS molecules bound to the second site of albumin is affected by temperature and pH. The saturation of the first binding site of BSA (ca. 0.009 mg of SDS per 1 mg of BSA) is sufficient to thermally stabilize the helical conformation of BSA. The presented results have important structural and thermodynamic implications to understand the influence of a widely used anionic surfactant on globular protein functionality in modern branches of chemistry.

Production of biodiesel from oleaginous fungal lipid using highly catalytic bimetallic gold-silver core-shell nanoparticle.

This study aims to synthesize, characterize and apply gold-silver core-shell nanoparticles (Au@Ag NPs), a nanocatalyst, to maximize biodiesel production from fungal isolate Fusarium solani (FS12) via a transesterification one-step reaction. The Au@Ag NPs structure was examined by UV-vis spectrophotometer, transmission electron microscopy, X-ray diffraction and Fourier transform infrared (FTIR). All devices were used to characterize Au@Ag NPs and confirmed successful synthesis of nanoparticles. Fungal lipid was quantitatively determined by sulfo-phospho-vanillin colorimetric method. Among 15 F. solani isolates obtained from rhizospheric soils of the date palm, F. solani (AF12) was chosen as the highly significant producer that accumulates above 20% lipid. The maximum biodiesel yield was 91.28±0.19%, obtained under the optimum reaction conditions of 3% Au@Ag NPs as nanocatalyst concentration, and 1:20 oil to methanol molar ratio at 70℃ for 30min. HPLC method was applied for monitoring in situ transesterification reaction. FTIR spectroscopy was used in qualitative analysis of biodiesel by verifying the presence of unique characteristic peaks of diagnostic significance. The quality of the biodiesel produced was confirmed by the high purity of fatty acid methyl esters analysis content up to >99%. These findings propose the applicability of F. solani (FS12) as a promising isolate to accumulate lipids and biodiesel production as a feedstock. The link between nanotechnology and fungi. Au@Ag NPs were synthesized at room temperature, which displayed high catalytic activity for in situ transesterification reaction. Catalytic activity appeared at low temperature, mole ratio and short reaction time. Oleaginous fungi are described as easily grown, have short life cycle, are cost-effective, and they utilized various sources of carbon up to waste and a simplified process to develop scale-up production as well, economic value, opposite the usage of vegetable oils which need for large agricultural areas.

Mitochondrial membranes modify mutant huntingtin aggregation

Huntington's disease (HD) is a neurodegenerative disease caused by the expansion of a polyglutamine (polyQ) tract near the N-terminus of the huntingtin (htt) protein. Expanded polyQ tracts are prone to aggregate into oligomers and insoluble fibrils. Mutant htt (mhtt) localizes to variety of organelles, including mitochondria. Specifically, mitochondrial defects, morphological alteration, and dysfunction are observed in HD. Mitochondrial lipids, cardiolipin (CL) in particular, are essential in mitochondria function and have the potential to directly interact with htt, altering its aggregation. Here, the impact of mitochondrial membranes on htt aggregation was investigated using a combination of mitochondrial membrane mimics and tissue-derived mitochondrial-enriched fractions. The impact of exposure of outer and inner mitochondrial membrane mimics (OMM and IMM respectively) to mhtt was explored. OMM and IMM reduced mhtt fibrillization, with IMM having a larger effect. The role of CL in mhtt aggregation was investigated using a simple PC system with varying molar ratios of CL. Lower molar ratios of CL (<5%) promoted fibrillization; however, increased CL content retarded fibrillization. As revealed by in situ AFM, mhtt aggregation and associated membrane morphological changes at the surface of OMM mimics was markedly different compared to IMM mimics. While globular deposits of mhtt with few fibrillar aggregates were observed on OMM, plateau-like domains were observed on IMM. A similar impact on htt aggregation was observed with exposure to purified mitochondrial-enriched fractions. Collectively, these observations suggest mitochondrial membranes heavily influence htt aggregation with implication for HD.

CO2 Capture in Biocompatible Amino Acid Ionic Liquids: Exploring the Reaction Mechanisms for Bimolecular Absorption Processes.

CO2 capture at the production site represents one of the accessible ways to reduce its emission in the atmosphere. In this context, CO2 chemisorption is particularly advantageous and is often based on exploiting a liquid containing amino groups that can trap CO2 due to their propensity to react with it to yield carbamic derivatives. A well-known class of ionic liquids based on amino acid anions might represent an ideal medium for CO2 capture because, at difference with present implementations, they are known to be fully biocompatible. One of the problems is however the relatively low molar ratio of CO2 absorption. Increasing this ratio turns out to be possible by choosing appropriate anions. We present here a set of accurate computations to elucidate the possible reaction paths that allow the anion to absorb two CO2 molecules, thus effectively doubling the overall intake. An extensive exploration of some reaction mechanisms suggests that some of them might be quite efficient even under mild conditions.

Investigations of the photochemical charge-transfer reduction of uranyl UO22+(VI) to uranyl UO2+(V) by benzene-1,4-diol (1,4-C6H4(OH)2) and oxalate (C2O42−) by UV–Vis, electron paramagnetic resonance, and luminescence spectroscopies

The aqueous mixtures of UO22+(VI) (as the nitrate salt) with benzene-1,4-diol (hydroquinone, HQ) 1,4-C6H4(OH)2 and those with oxalate C2O42− (as the sodium salt) exhibited broad absorptions at 350–400 nm in their UV–Vis spectra. The intensities of the absorptions for both the UO22+(VI)–HQ and UO22+(VI)–C2O42− mixtures, represented by the absorbance at 375 nm, were shown to be directly proportional to the molar concentrations of HQ and C2O42−, respectively. For each mixture, the absorbance was also found to be directly proportional to the molar concentration of UO22+(VI). The broad absorptions are characteristic of the charge-transfer (CT) bands from the electron-donor–acceptor (EDA) complexes formed between UO22+(VI) and HQ and between UO22+(VI) and C2O42−. Upon photolysis of the UO22+(VI)–HQ and UO22+(VI)–C2O42− mixtures, UO22+(VI) was found by electron paramagnetic resonance (EPR) to be reduced to UO2+(V) (g = 2.08) by HQ and C2O42−, respectively (CT reductions), and the hydroquinone radical 1,4-HOC6H4O. (HQ.) (g = 2.00) was identified simultaneously by EPR spectroscopy. Both HQ and C2O42− at the very low molar ratios of [HQ]/[UO22+] < 1/100 and [C2O42−]/[UO22+] < 1/100 were shown to quench the UO22+ luminescence (emission) for more than 60%. The quenching constants of HQ and C2O42− were determined to be 10,800 M−1 and 4,300 M−1, respectively, using the Stern-Volmer relationship. The results indicated a CT quenching mechanism, namely that the interactions of HQ and C2O42− with the excited *UO22+(VI) lead to transfer of a single electron from the quencher to *UO22+(VI) to reduce it to UO2+(V). This converts the light energy to chemical energy to quench the UO22+(VI) luminescence. Possible photochemical processes associated to the UO22+(VI)–HQ and UO22+(VI)–C2O42− redox reactions have been proposed on the basis of the UV–Vis, EPR, and luminescence spectroscopic studies.

Bio-Mediated Soil Improvement Using Plant Derived Enzyme in Addition to Magnesium Ion

Recently, soil improvement using EICP (Enzyme-Induced Carbonate Precipitation) methods in the geotechnical and geo-environmental field has become a prominent interest worldwide. The objective of this study was to develop an improved extraction technique of crude urease from watermelon seeds in both dry and germinated conditions. Subsequently, this study also analyzed the improvement methodology of crystal polymorphs and soil bonding incorporation of various Mg2+/Ca2+ ratios. The optimization of enzyme-mediated carbonate precipitation was also investigated by Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) analysis. Results confirmed that the precipitated crystals are mainly calcite, vaterite and aragonite primarily (depending on the Mg2+/Ca2+ ratios). Therefore, to improve the bonding capacity in between the sand particles a novel improvement methodology was investigated by adding various Mg2+/Ca2+ ratios. The mechanical properties of the treated soil (Mikawa Sand, D50 = 0.870 mm) specimens were tested by unconfined compressive strength (UCS) and this confirmed the effectiveness of adding various Mg2+/Ca2+ ratios. The results of the UCS tests showed that, the lower molar ratios of Mg2+/Ca2+ can significantly improve the UCS of the specimen (up to 50%) which could be considered a significant outcome for different bio-geotechnical applications.

In-situ synthesis of zirconium oxycarbide by electroreduction of ZrO2/C in molten salt

Homogenous ZrCxOy powders have been successfully synthesized by in-situ electro-reduction of solid ZrO2–C composite precursors in molten CaCl2. The effect of applied cell voltage and molar ratio of ZrO2 to C on preparation of ZrCxOy were investigated. The reduction pathway of the composite electrode was studied based on the analysis of intermediate products using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that ZrO2 is firstly converted to CaZrO3. The resulting CaZrO3 is then reduced to ZrCxOy. The ZrCxOy formation is dramatically influenced by electrolysis voltage and molar ratio of ZrO2 to C: a higher cell voltage and lower molar ratio of the ZrO2 to C are more preferable for the formation of ZrCxOy powder. Homogenous ZrCxOy powders with particle size of ~100 nm are synthesized by ZrO2/C starting elemental powders in CaCl2 molten salt at 1123 K for more than 3 h, when the cell voltage is 3.0 V and the molar ratio of the ZrO2 to carbon starting materials is 1:1.0.

Evidence of Phosphate Mining and Agriculture Influence on Concentrations, Forms, and Ratios of Nitrogen and Phosphorus in a Florida River

Florida has a long history of phosphate-mining, but less is known about how mining affects nutrient exports to coastal waters. Here, we investigated the transport of inorganic and organic forms of nitrogen (N) and phosphorus (P) over 23 sampling events during a wet season (June–September) in primary tributaries and mainstem of Alafia River that drains into the Tampa Bay Estuary. Results showed that a tributary draining the largest phosphate-mining area (South Prong) had less flashy peaks, and nutrients were more evenly exported relative to an adjacent tributary (North Prong), highlighting the effectiveness of the mining reclamation on stream hydrology. Tributaries draining &gt; 10% phosphate-mining area had significantly higher specific conductance (SC), pH, dissolved reactive P (DRP), and total P (TP) than tributaries without phosphate-mining. Further, mean SC, pH, and particulate reactive P were positively correlated with the percent phosphate-mining area. As phosphate-mining occurred in the upper part of the watershed, the SC, pH, DRP, and TP concentrations increased downstream along the mainstem. For example, the upper watershed contributed 91% of TP compared to 59% water discharge to the Alafia River. In contrast to P, the highest concentrations of total N (TN), especially nitrate + nitrite (NOx–N) occurred in agricultural tributaries, where the mean NOx–N was positively correlated with the percent agricultural land. Dissolved organic N was dominant in all streamwaters and showed minor variability across sites. As a result of N depletion and P enrichment, the phosphate-mining tributaries had significantly lower molar ratios of TN:TP and NOx–N:DRP than other tributaries. Bi-weekly monitoring data showed consistent increases in SC and DRP and a decrease in NOx–N at the South Prong tributary (highest phosphate-mining area) throughout the wet season, and different responses of dissolved inorganic nutrients (negative) and particulate nutrients (positive) to water discharge. We conclude that (1) watersheds with active and reclaimed phosphate-mining and agriculture lands are important sources of streamwater P and N, respectively, and (2) elevated P inputs from the phosphate-mining areas altered the N:P ratios in streamwaters of the Alafia River.

Post-synthesis of biomimetic chitosan with honeycomb-like structure for sensitive recognition of phosphorylated peptides

Chemical modification of biological materials is indispensable for enrichment of phosphorylated peptides. In this work, we synthesized a biomimetic honeycombed affinity chromatography (IMAC) adsorbent by preparing Crosslinked Chitosan, chelating aminomethyl phosphate decorated with Ti (IV) cation. The as-prepared CTSM@AMPA-Ti4+ composites with stable structure, low steric hindrance, and high Ti4+ loading amount were used as a promising adsorbent for enrichment of phosphopeptides. CTSM@AMPA-Ti4+ showed extremely high sensitivity (0.4 fmol) and selectivity at a low composition molar ratio of β-casein/BSA (1:1000). What's more, it can keep its performance in the case that used to capture phosphorylated peptides from standard protein ten times or soaking in the acid/base solution for a long time. In addition, CTSM@AMPA-Ti4+ successfully captured 35 phosphorylated peptides from human saliva. This study offers a way about diversiform functionalization of CTSM in phosphoproteome analysis and disease research.