Anionic Clays as Potential Slow-Release Fertilizers: Nitrate Ion Exchange

Several nitrate containing anionic clays were synthesized at different temperatures and the kinetics of NO₃ ^– release were determined to test their suitability as slow-release N fertilizers. A sample (Mg:Al = 2:1) synthesized at 60°C with smaller particle size released 75, 86 and 100% of its NO₃ ^– in 1, 3 and 7 days, respectively when equilibrated with a simulated soil solution. On the other hand, the 175°C/2 hrs sample with larger particle size released 65, 77 and 84% of its nitrate in 1, 3 and 7 days, respectively. Another anionic clay (synthesized at 175°C/24 hrs) of higher charge density (Mg:Al = 2:1) containing NO₃ ^– was equilibrated with a 0.012 N NaCl or Na₂CO₃ to test the role of different anions in releasing the NO₃ ^– anion from the interlayers. The results showed that Cl^– released more NO₃ ^– than did CO₃ ^2– from this anionic clay after all the treatment times probably as a result of the CO₃ ^2– anion blocking the release of NO₃ ^– from the interior of the crystals. When a lower charge density (Mg:Al = 3:1) sample (synthesized at 175°C/48 hrs) was equilibrated with 0.02N solution of anions the release of nitrate was as follows: Cl^– < F^– < SO₄ ⁼ CO₃ ^2–. These results suggest that the divalent SO₄ ⁼ and CO₃ ^2– anions are more effective in the release of NO₃ ^– from this lower charge density anionic clay. Time-resolved structural analysis of NO₃ ^– exchange with CO₃ ^2– in the above anionic clay using synchrotron x-ray diffraction showed that ion exchange is rapid because of small crystal size and lower charge density. Thus the release of NO₃ ^– from anionic clays is an interplay among the type of anions present in soil solution, their concentration, pH of soil solution, the charge density and crystal size of anionic clay etc.     

Rapid On-Resin N-Formylation of Peptides as One-Pot Reaction

N-formylation is a common pre- and post-translational modification of the N-terminus or the lysine side chain of peptides and proteins that plays a role in the initiation of immune responses, gene expression, or epigenetics. Despite its high biological relevance, protocols for the chemical N-formylation of synthetic peptides are scarce. The few available methods are elaborate in their execution and the yields are highly sequence-dependent. We present a rapid, easy-to-use one-pot procedure that runs at room temperature and can be used to formylate protected peptides at both the N-terminus and the lysine side chain on the resin in near-quantitative yields. Only insensitive, storage-stable standard chemicals – formic acid, acetic anhydride, pyridine and DMF – are used. Formylation works for both short and long peptides of up to 34 amino acids and over the spectrum of canonical amino acids.     

Conformational,thermal, and ionic conductivity behavior of PEO in PEO/PMMA miscible blend: Investigating the effect of lithium salt

In this research, influence of incorporating LiClO₄ salt on the crystallization, conformation, and ionic conductivity of poly(ethylene oxide) (PEO) in its miscible blend with poly(methyl methacrylate) (PMMA) is studied. Differential scanning calorimetry showed that the incorporation of salt ions into the blend suppresses the crystallinity of PEO. The X‐ray diffraction revealed that the unit‐cell parameters of the crystals are independent of the LiClO₄ concentration despite of the existence of ionic interactions between PEO and Li cations. In addition, the complexation of the Li⁺ ions by oxygen atoms of PEO is investigated via Fourier transform infrared spectroscopy. The conformational changes of PEO segments in the presence of salt ions are studied via Raman spectroscopy. It is found that PEO chains in the blend possess a crown‐ether like conformation because of their particular complexation with the Li⁺ ions. This coordination of PEO with lithium cations amorphize the PEO and is accounted for suppressed crystallinity of PEO in the presence of salt ions. Finally, electrochemical impedance spectroscopy is used to characterize the ionic conductivity of PEO in the PEO/PMMA/LiClO₄ ternary mixture at various temperatures. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Thin-Layer Drying Characteristics and Quality Evaluation of Air-Dried Ganoderma Tsugae Murrill

Ganoderma is normally dried to extend its shelf life without using chemical preservative and to concentrate the medicinal value in the fruiting body. Convective hot air drying characteristics of Ganoderma tsugae Murrill were evaluated in hot air circulated oven at different drying temperatures, sizes, and air flow rates. The drying kinetics of Ganoderma tsugae in kidney shape and slices were investigated and compared at different drying conditions. The variation of effective moisture diffusivity values at decreasing moisture contents during drying was determined from the drying data. Four well-known thin-layer drying models were fitted to the experimental data and the Midilli model was found to satisfactory describe the drying characteristics of kidney-shaped Ganoderma tsugae. Ganoderma tsugae dried at 50°C with air velocity of 1.401 ms^?1 showed the highest retention of crude ganoderic acid content compared to other drying conditions.     

Identification of purple dye from molluscs on an excavated textile by non-destructive analytical techniques

The inherent sensitivity of textile fibres to the aggressive process of burial accounts for the rarity and poor condition of excavated textile finds retrieved. However, the information contained within these finds is important and yielding it contributes to the longevity of the finds. Therefore, the application of non-destructive methods of investigation for the extraction of the data present is imperative. This paper presents the results of dye analysis performed on the excavated textile find HTR-73 from the Kerameikos cemetery in Athens. The Kerameikos textile find is from the 5th century BC, and has been preserved in association with copper. The techniques applied were Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX) analysis, Cathodoluminescence and micro Raman. For the first time Cathodoluminescence from an indigoid compound is reported. Comparison of the analysis results on samples from the find with the contemporary reference samples lead to the identification of purple dye as a dibromoindigo compound with the origin from molluscs of Murex trunculus species. The application of non-destructive analytical methods of investigation was successful in analysing dyes on excavated textiles.     

SIMULATION STUDIES OF THE REMOVAL OF WATER FROM ETHANOL BY A CATALYTIC DISTILLATION PROCESS

A new approach based on catalytic distillation (CD) technology was proposed to remove water from ethanol. Isobutylene was introduced to react with water in the CD column. The commercial software simulation tool Aspen Plus was used to investigate the effects of key design factors such as operating pressure and temperature, reactant ratios, reflux and distillate to feed ratios, number of separation and reaction stages, and feed and reaction zone location. It was found that the CD technology offers potential advantages of reduced energy consumption and reduced capital cost over traditional approaches for the removal of water from ethanol.     

Enantioselective Platinum‐Catalyzed Silicon‐Boron Addition to 1,3‐Cyclohexadiene

Silaboration of 1,3‐cyclohexadiene in the presence of Pt(acac)₂, DIBALH, and a phosphoramidite prepared from (S)‐1,1′‐bi‐2‐naphthol and diisopropylamine led to (1R,4S)‐1‐(dimethylphenylsilyl)‐4‐(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)‐2‐cyclohexene with 70% ee. Chiral catalysts based on Ni gave no or essentially racemic product, whereas complexes containing Pd were inactive.     

Lymphatic transport in rats of interesterified oils containing conjugated linoleic acids

In this study we examined the lymphatic transport in rats of FA after administration of interesterified oils containing CLA, with emphasis on the location of CLA and octanoic acid in the TAG. The oils were produced by enzymatic interesterification. Eight oils with different structures or FA profiles were examined in this study: MCM, CMC, OCO, and COC, where M was expected to be octanoic acid and O oleic acid. In group 1, C was CLA as a mixture of the two CLA isomers c9, t11 or t10, c12, and in group 2, C was mainly the isomer t10, c12. Rats were subjected to cannulation of the mesenteric lymph duct, and the following day they were intragastrically administered one of the oils and lymph samples were collected for 24 h. The lymphatic transport of total FA from 0 to 8 h in group 1 was significantly (P < 0.05) higher for the OCO-1 and the COC-1 oils than for the CMC-1 oil. Similarly, in group 2 the transport was higher for the OCO-2 oil than for the CMC-2 oil. The recovery of both of the CLA isomers examined was similar (50-70%) and independent of the isomer, oil structure, and FA profile, whereas more octanoic acid was recovered from the CMC oils than from the MCM oils. The results indicated that the FA profiles and the position of octanoic acid had only a minor influence on the absorption of CLA.