Investigation of Yeast Invertase Immobilization onto Cupric Ion-Chelated,Porous, and Biocompatible Poly(Hydroxyethyl Methacrylate-<Emphasis Type="Italic">n</Emphasis>-Vinyl Imidazole) Microspheres

Cupric ion-chelated poly(hydroxyethyl methacrylate-n-vinyl imidazole) (poly(HEMA-VIM)) microspheres prepared by suspension polymerization were investigated as a specific adsorbent for immobilization of yeast invertase in a batch system. They were characterized by scanning electron microscopy, surface area, and pore size measurements. They have spherical shape and porous structure. The specific surface area of the p(HEMA-VIM) spheres was found to be 81.2 m²/g with a size range of 70–120 μm in diameter, and the swelling ratio was 86.9%. Then, Cu(II) ion chelated on the microspheres (546 μmol Cu(II)/g), and they were used in the invertase adsorption. Maximum invertase adsorption was 51.2 mg/g at pH 4.5. Cu(II) chelation increases the tendency from Freundlich-type to Langmuir-type adsorption model. The optimum activity for both free and adsorbed invertase was observed at pH 4.5. The optimum temperature for the poly(HEMA-VIM)/Cu(II)-invertase system was found to be at 55 °C, 10 °C higher than that of the free enzyme at 45 °C. V _max values were determined as 342 and 304 U/mg enzyme, for free and adsorbed invertase, respectively. K _m values were found to be same for free and adsorbed invertase (20 mM). Thermal and pH stability and reusability of invertase increased with immobilization.     

Organometallic ruthenium, rhodium and iridium complexes containing a P-bound thiophene-2-(N-diphenylphosphino)methylamine ligand: Synthesis, molecular structure and catalytic activity

Reaction of Ph₂PNHCH₂-C₄H₃S with [Ru(η⁶-p-cymene)(μ-Cl)Cl]₂, [Ru(η⁶-benzene)(μ-Cl)Cl]₂, [Rh(μ-Cl)(cod)]₂ and [Ir(η⁵-C₅Me₅)(μ-Cl)Cl]₂ yields complexes [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-p-cymene)Cl₂], 1, [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-benzene)Cl₂], 2, [Rh(Ph₂PNHCH₂-C₄H₃S)(cod)Cl], 3 and [Ir(Ph₂PNHCH₂-C₄H₃S)(η⁵-C₅Me₅)Cl₂], 4, respectively. All complexes were isolated from the reaction solution and fully characterized by analytical and spectroscopic methods. The structure of [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-benzene)Cl₂], 2 was also determined by single crystal X-ray diffraction. 1-4 are suitable precursors forming highly active catalyst in the transfer hydrogenation of a variety of simple ketones. Notably, the catalysts obtained by using the ruthenium complexes [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-p-cymene)Cl₂], 1 and [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-benzene)Cl₂], 2 are much more active in the transfer hydrogenation converting the carbonyls to the corresponding alcohols in 98-99% yields (TOF ≤ 200 h⁻¹) in comparison to analogous rhodium and iridium complexes.     

N1‐(4‐tert‐Butyl­phenyl)‐N2‐hydroxy‐α‐oxo‐α‐phenyl­acet­amidine and N2‐hydroxy‐N1‐(4‐nitro­phenyl)‐α‐oxo‐α‐phenyl­acet­amidine hemihydrate

In the title compounds, C₁₈H₂₀N₂O₂, (I), and C₁₄H₁₁N₃O₄·0.5H₂O, (II), respectively, the oxime groups have an E configuration. In (I), the mol­ecules exist as polymers bound by intermolecular C—H⋯O and O—H⋯N hydrogen bonds around inversion centres. In (II), intermolecular OW—H⋯N, OW—H⋯O and O—H⋯OW interactions stabilize the molecular packing.     

Construction of Different Kinds of Atomic and Molecular Orbitals Using Complete Orthonormal Sets of ψ^α-ETO in Single Exponent Approximation

Using complete orthonormal sets of ψ^α-exponential type orbitals in single exponent approximation the new approach has been suggested for construction of different kinds of functions which can be useful in the theory of linear combination of atomic orbitals. These functions can be chosen properly according to the nature of the problems under consideration. This is rather important because the choice of the basis set may be play a crucial role in applications to atomic and molecular problems. As an example of application, different atomic orbitals for the ground states of the neutral and the first ten cationic members of the isoelectronic series of He atom are constructed by the solution of Hartree-Fock-Roothaan equations using ψ^1, ψ^0 and ψ^-1 basis sets. The cMculated results are close to the numerical Hartree-Fock values. The total energy, expansion coefficients, orbital exponents and virial ratio for each atom are presented.     

Kraus decomposition for chaotic environments

We consider a system interacting with a chaotic thermodynamic bath. We derive an explicit and exact Kraus operator sum representation (OSR) for the open system reduced density. The OSR preserves the Hermiticity, complete positivity and norm. We show that it is useful as a numerical tool by testing it against exact results for a qubit interacting with an isolated flawed quantum computer. We also discuss some interesting qualitative aspects of the OSR.     

Bond cutting in K‐doped tris(8‐hydroxyquinoline) aluminium

A series of Al 2p, K 2p, O 1s and N 1s core‐level spectra have been used to characterize the interaction between potassium (K) and tris(8‐hydroxyquinoline) aluminium (Alq₃) molecules in the K‐doped Alq₃ layer. All core‐level spectra were tuned to be very surface sensitive in selecting various photon energies provided by the wide‐range beamline at the National Synchrotron Radiation Research Center, Taiwan. A critical K concentration (x = 2.4) exists in the K‐doped Alq₃ layer, below which the K‐doped atoms generate a strained environment near the O and N atoms within 8‐quinolinoline ligands. This creates new O 1s and N 1s components on the lower binding‐energy side. Above the critical K coverage, the K‐doped atoms attach the O atoms in the Al—O—C bonds next to the phenoxide ring and replace Al—O—C bonds by forming K—O—C bonds. An Alq₃ molecule is disassembled into Alq₂ and Kq by bond cutting and bond formation. The Alq₂ molecule can be further dissociated into Alq, or even Al, through subsequent formations of Kq.     

Amorphous silicon hexaboride: a first-principles study

We report for the first time the atomic structure, electronic structure and mechanical properties of amorphous silicon hexaboride (a-SiB₆) based on first-principles molecular dynamics simulation. The a-SiB₆ model is generated from the melt and predominantly consists of pentagonal pyramid-like configurations and B₁₂ icosahedral molecules, similar to what has been observed in most boron-rich materials. The mean coordination number of B and Si atoms are 5.47 and 4.55, respectively. The model shows a semiconducting behaviour with a theoretical bandgap energy of 0.3?eV. The conduction tail states are found to be highly localised and hence the n-type doping is suggested to be more difficult than the p-type doping for a-SiB₆. The bulk modulus and Vickers hardness of a-SiB₆ are estimated to be about 118 and 13–17?GPa, respectively.     

Archaeometric study of possible Ninevite‐5 pottery from upper Tigris region using SEM‐EDS,PEDXRF, and OM

This study aims to reveal the production technology of some representative samples of possible Ninevite‐5 potsherds which are generally dated between the Early Jezirah I to EJ‐II/EJ‐III periods (roughly 3000–2500 bc ) and accepted as the typical ceramics reflecting the northern Mesopotamian culture in the first half of the 3rd millennium BC. The samples were selected from the archeological excavation area of Kuriki (upper Tigris region, Turkey) and exposed to multiple analytical techniques including scanning electron microscopy with an energy dispersive spectrometer, optical microscopy, and polarized energy dispersive X‐ray fluorescence spectrometry. The results showed that all the samples have high amounts of CaO (up to 29.83 wt.%) indicating use of calcareous clay deposits and they have an analogous chemical compositions in terms of both major oxides and trace elements which implied the use of the same raw materials. The vitrification degrees of the samples, examined by back scattered electron images, suggested that the firing temperature of the potsherds did not exceed the range of 800–900°C. It was also revealed that the firing atmosphere was oxidative which would be attributed to use of kiln firing rather than a bonfire or pit firing. Both the chemical and petrographic results suggested that the investigated samples presumably belong to a regional (upper Tigris) production rather than a local one.     

Single-ion conductivity enhancement for the composite polymer electrolytes based on Li(PVAOB)/PPEGMA for lithium-ion batteries

In the present work, a series of single-ion conducting composite polymer electrolytes based on lithium polyvinyl alcohol oxalate borate (Li(PVAOB)) and poly(polyethylene glycol methacrylate) (PPEGMA) were produced. PEGMA was polymerized into PPEGMA, and the Li(PVAOB) was prepared from poly (vinyl alcohol) (PVA), oxalic acid, and boric acid. Li(PVAOB) was blended with PPEGMA at different stoichiometric ratios to obtain a single-ion conducting system. All the electrolytes were characterized by Fourier transformation infrared spectroscopy (FT-IR), thermogravimetry analysis (TGA), differential scanning calorimeter (DSC), and scanning electron microscopy (SEM) techniques. These results verified the interaction between host and guest polymers, sufficient thermal stability within the measured conductivity domain, and the homogeneity of the composite electrolytes. The effect of PPEGMA onto the ionic conductivity was investigated using impedance spectroscopy. The Li(PVAOB)-60PPEGMA is the optimum content, and this sample has a maximum ionic conductivity of 3 × 10^?4 S/cm at 100 °C which is approximately five orders of magnitude higher than neat Li(PVAOB). Activation energy (E _a ) of ionic transport decreased from 11.9 to 0.27 kJ/mol, suggesting a much faster ionic mobility for higher PPEGMA-containing samples.