Radical of filters in BL‐algebras

In this paper, the notion of the radical of a filter in BL‐algebras is defined and several characterizations of the radical of a filter are given. Also we prove that A/F is an MV‐algebra if and only if D_s(A) ? F. After that we define the notion of semi maximal filter in BL‐algebras and we state and prove some theorems which determine the relationship between this notion and the other types of filters of a BL‐algebra. Moreover, we prove that A/F is a semi simple BL‐algebra if and only if F is a semi maximal filter of A. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

Investigation of the electronic structure and the structural stability of selected penicillins by density functional calculations of 14N nuclear quadrupole resonance parameters

A computational study was carried out by density functional theory (DFT) to investigate the relative stability and reactivity in three selected penicillins: penicillin-G, penicillin-V and carbenicillin. The geometry of the investigated molecules was optimized at the B3LYP/6-31G(d) level of theory. Then, the nuclear quadrupole resonance (NQR) parameters of ¹⁴N and ²H nuclei and natural bond orbital (NBO) analysis in these molecules were calculated on the geometrically optimized models at the B3LYP level using 6-311++G(d,p) basis sets in the gas phase. The NBO analysis shows that the occupancy of the LP(N) decreases with increasing p character of the lone pair of nitrogen. A comparison between the results obtained for these penicillins and related 6-APA structures of them indicates that the presence of a bulky side group in the acyl side chain can lead to more stability of the β-lactam ring. On the other hand, NBO analysis was applied to rationalize the ¹⁴N NQR parameters in the charge distribution around nitrogen atoms. Inspection of the present results illustrates that the largest component of EFG tensor (q _zz ), the nuclear quadrupole coupling constant, C _Q, and the NQR frequency values of nitrogens decrease with decreasing occupancy values of LP(N). We suggest that the reason for this trend can be found in increasing contribution of delocalized electrons of nitrogen in the intramolecular interactions and hence stability of these structures increases in the order: PG < PV < CA. Finally, a good relationship is found between most of the calculated ²H NQR parameters and the related intramolecular hydrogen bonds.     

A quantum chemistry study of ruthenabenzene complexes

The electronic structure and properties of the ruthenabenzenes and substituted ruthenabenzenes have been explored using the hybrid density functional B3LYP theory. Systematic studies on the substituent effect in para-substituted ruthenabenzenes complexes have been studied. The following substituents were taken into consideration: H, NO₂, CN, CHO, COOH, F, CH₃, OH, and NH₂. Basic measures of aromatic character were derived from the structure and nucleus-independent chemical shift (NICS). The NICS calculations indicate a correlation between NICS(1.5) and the hardness in all species. The atoms in molecule analysis indicates a correlation between r(Ru-C) bonds and the electron density of bond critical point in all species.     

Solid polymer nanocomposite electrolytes based on poly(ε-caprolactone)-based waterborne polyurethane–polyethylene oxide and fluorine-doped carbon quantum dot-MXene

The need for higher energy storage capability has encouraged researchers to move toward lithium-metal batteries (LMBs). Due to the safety issue associated with liquid electrolytes, solid polymer electrolytes (SPEs) the main focus on polyethylene oxide (PEO) were at the center of the research. However, high crystallization, fast decomposition, and low thermomechanical stability has limited its application. Low lithium-ion transference number ( $$) is another issue leading to polarization of the SPEs and consequently, triggering dendrite nucleation and growth. Here, we developed a series of SPEs based on PEO-waterborne polyurethane (WPU) and nanoparticles of fluorine-doped carbon quantum dot (fCQD) and MXene. The host polymer matrix was a blend of poly(ε-caprolactone) (PCL)-based WPU and PEO. The use of WPU and the nanoparticles increased the thermomechanical stability and suppressed PEO crystallinity through disrupting the spherulites growth and reducing the thermal stability of the crystallites. Using the WPU led to significant increase in $$ ( $$) compared with previous reports. The prepared SPEs showed high-electrochemical stability and ionic conductivity at $$ and based on the results of cycling performance, a discharge capacity of 120.58 mAh/g and coulombic efficiency of 99.1% was achieved after 200 cycles.     

Efficient synthesis of β-aminoketones catalyzed by Fe3O4@ quillaja sapogenin/Ni (II) as a novel magnetic nano-catalyst

A new nano-magnetic core–shell Fe₃O₄@quillaja sapogenin/Ni (II) was synthesized and characterized thoroughly using various tests including energy-dispersive X-ray spectroscopy (EDS), Brunauer–Emmett–Teller (BET), thermo-gravimetric analysis (TGA), high-resolution transmission electron microscopy (HR-TEM), vibrating sample magnetometer (VSM), Fourier transform infrared (FT-IR) spectroscopy, inductively coupled plasma (ICP), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The achievements demonstrated that the proposed agents were beneficial to synthesis the derivatives of β-aminoketone. Moreover, it was possible to recover the catalyst by means of simple magnetic decantation quickly. Besides, no reduction in the activity of the catalyst occurred, even though it was utilized in various reactions.     

Nano‐structured gemini‐based supramolecular solvent for the microextraction of cyhalothrin and fenvalerate

A novel supramolecular solvent‐based microextraction followed by high‐performance liquid chromatography with ultraviolet detection method has been developed for the extraction and determination of two pyrethroid analytes, cyhalothrin and fenvalerate, in water and soil samples. The liquid–liquid‐phase separation of surfactants has been used in analytical extraction. The surfactant‐rich phase is a nano‐structured liquid, recently named as a supramolecular solvent, generated from the amphiphiles. The alkyl carboxylic acid based supramolecular solvents were introduced before. Coacervates made up of gemini surfactant, consisting of two amphiphilic moieties, were first used as solvent. The effective parameters on extraction (i.e., type of organic solvent, the amount of surfactant and volume of tetrahydrofuran, sample solution pH, salt addition, ultrasonic and centrifugation time) were investigated and optimized. Under the optimum conditions, preconcentration factors of 110 and 145 were obtained for the analytes. The linearity was 0.5–200.0 μg/L with the correlation of determination of (R²) ≥ 0.9984. The limit of detection of the method was (S/N = 3) 0.2 μg/L, and precisions in the range of 6.3–10.3% (RSDs, n = 5) were obtained. This method has been successfully applied to analyze real samples, and good recoveries in the range of 101.2–108.8% were obtained.     

Combining gold nanoparticle-based headspace single-drop microextraction and a paper-based colorimetric assay for selenium determination

Analytical and Bioanalytical Chemistry - A novel method combining headspace single-drop microextraction with a paper-based colorimetric assay was developed. Headspace single-drop microextraction...     

Increasing proteome coverage for gel‐based human tear proteome maps: towards a more comprehensive profiling

In situations where the molecular mechanism of many ocular disorders is unknown, owing to the difficulties associated with sampling from ocular tissues, human tear film can be a promising medium in ophthalmic research. The present study demonstrates an in‐depth gel‐based proteome optimization survey to approach more appropriate and efficient systems in various situations such as normal and dry‐eye syndromes. Therefore, systematic and statistical evaluations were performed on different preparation methods, including acetone, acetone–methanol, chloroform–methanol–water, trichloroacetic acid (TCA)–acetone, tri‐n‐butylphosphate–acetone–methanol precipitations and ammonium sulfate fractionation at three different percentages of saturations (50, 70 and 90%). Methods were compared quantitatively on both one‐ and two‐dimensional patterns. Some important parameters such as total protein recovery yield, densitometric analysis of some protein contaminants, banding patterns and total spot numbers along with statistical models for proper clustering were considered. Findings revealed noticeable impacts of preparation methods on all aspects of gel‐based separations as well as recovery yield (ranging from 5.29 ± 0.96 to 22.56 ± 1.77 µg/mm) and banding and pattern resolution. In addition to all these, the most important point is that the total protein spot number on the final two‐dimensional patterns (varied from 528.00 ± 19.00 to 657.00 ± 21.52 for different methods) were also noticeably increased in comparison with previously published reports (maximum of 250 spots), which is essential for a more comprehensive analysis. Increasing the proteome coverage in the present study is supposed to originate from improved solubility and effective rehydration during the sample application and isoelectric focusing (IEF) procedure along with proper sample preparation. Copyright © 2014 John Wiley & Sons, Ltd.     

An unusual way of formation of spirophosphoranes during the oxidative addition of hexafluoroacctone to σ5P-σ3P-diphosphorus compounds,and in the reaction of 2-chloro-l,2-dimethyl-3-phenyl-2-phenylseleno-l,3,5σ5-diazaphosphetidin-4-one with bis(2-chloroethyl)amine hydrochloride/ triethylamine

The reaction of (chloromethyl)dichlorophosphine 1 with N,N′-dimethyl-N,N′-bis(trimethylsilyl)urea 2 furnished the σ⁵P-σ³P-diphosphorus compound 3 . The reaction of 3 with hexafluoroacetone proceeded in an unusual fashion, with the rupture of the P? P bond, resulting in 4,4-bis(trifluoromethyl)-3-chloro-2-hexfluoroisopropoxy-2-oxo-1,2-oxaphosphetane 7 and the spirophosphorane 4-chloromethyl-1,3,5,7-tetramethyl-1,3,5,7-tetraaza-4σ⁵-phosphaspiro-[3,3]heptan-2,6-dione 8 . The reaction of 2-chloro-1,2-dimethyl-3-phenyl-2-phenylseleno-1,3,2σ⁵-diazaphosphetidin-4-one 9 with bis(2-chloroethyl)amine hydrochloride/triethylamine 10 also proceeded in an unexpected fashion, leading to the spirophosphorane 11 as the only identified product. Single-crystal X-ray structure analyses of compounds 8 and 11 were conducted. The coordination geometry at phosphorus in both compounds shows a large deviation from idealized forms. This distortion arises mainly from the presence of the four-membered rings.     

Relating the second and fourth order terms in the asymptotic expansion of the heat equation

Leta _n be the coefficients in the asymptotic expansion of the heat equation. In this paper, we study the relationship betweena ₂ ² anda ₄ in the context of both Riemannian and affine geometry.Research partially supported by the DFG project on Affine differential geometryResearch partially supported by the NSF (USA) and MSRI (USA)