Miracle-dz/UniFAR-FTUs huggingface dataset:
Pulse radiolytic studies of metallotexaphyrins in the presence of oxygen: Relevance of the equilibrium with superoxide anion to the mechanism of action of the radiation sensitizer motexafin gadolinium (Gd-Tex2+, xcytrin)

Pulse radiolytic studies of aqueous solutions of four representative metallotexaphyrin complexes M−Tex2+ (M = Gd(III), Lu(III), Dy(III), and Y(III)), carried out in the presence of either dioxygen, or trimethyl-p-benzoquinone (TMQ). It was found that all four of these M−Tex2+ species set up an equilibrium with superoxide and the singly reduced TMQ (TMQ•-) on the pulse radiolytic time scale. Rate constants for the forward (k1) and back (k-1) reactions of Gd−Tex2+ with superoxide anions, at pH 8.5, were determined to be (9.8 ± 1.5) × 106 M-1 s-1 and (3.4 ± 0.5) × 106 M-1 s-1, respectively. For reaction with TMQ•-, the analogous rate constants were found to be (1.5 ± 0.2) × 107 M-1 s-1 and (3.7 ± 0.6) × 106 M-1 s-1, respectively. Equilibrium constants (Kkin), calculated from these kinetic parameters, were found to be 2.9 and 4.1 for Gd−Tex2+ reacting with O2•- (to produce Gd−Tex•+ and O2) and TMQ•- (to produce Gd−Tex•+ and TMQ), respectively. Equilibrium constants for the M-Tex2+ species reacting with O2•- a.
Biomaterials for stem cell differentiation

Stem cell-based therapeutic treatments hold great promise in treating diseases by replacement of body parts and organs through the generation of new tissues. Directing the controlled differentiation of stem cells into a lineage-specific manner requires a controlled biophysical and biochemical microenvironment and signals. Biomaterials may act as artificial microenvironments and therefore, can deliver stem cell regulatory signals in a precise and near-physiological fashion. A variety of biomaterials are being developed that support cellular attachment, proliferation and most importantly lineage-specific differentiation. Development of new intelligent biomaterials in synergy with cell biology will advance stem cell-based clinical therapeutics. This review discusses the various biomaterials, in particular polymers, applied towards the goal of lineage-specific differentiation of stem cells.
AN AMPEROMETRIC BIOSENSOR FOR HYDROGEN PEROXIDASE BASED ON THE CO-IMMOBILIZATION OF CATALASE AND METHYLENE BLUE IN AN AL2O3 SOL-GEL MODIFIED ELECTRODE

A novel biosensor for the amperometric detection of hydrogen peroxide was developed based on the co-immobilization of catalase and methylene blue on an Al2O3 sol-gel fabricated glassy carbon electrode. The membrane structure of the sol-gel-immobilized catalase and methylene blue was studied with scanning electron microscopy. Cyclic voltammetric and amperometric measurements demonstrated that methylene blue co-immobilized with catalase in this way displayed good stability and efficiently shuttled electron between the immobilized enzyme and the electrode. Electrocatalytic reduction of H2O2 at the electrode was evaluated with respect to solution pH, operating potential and selectivity. The biosensor was stable at least for 3 weeks.
Crystal Structure of Ofloxacin Perchlorate

Quinolones are synthetic antibiotics with a broad spectrum of antimicrobial activity; ofloxacin (Fig. 1) is one of these agents, showing the most potent activity. A crystal of ofloxacin perchlorate was grown as a colorless prism, the structure of which was determined by X-ray analysis. The lattice parameters and intensities were measured by the 8 29 scan method on a Philips four-circle X-ray diffractometer with graphite monochromated Cu Ka radiation. Since the size of the crystal used was 0.3X0. 1X0.05 mm, no absorption correction was applied. The structure was solved by a direct method using partial structural data, and the Emap gave the locations of partial molecules. A weighted Fourier synthesis revealed the atomic positions of all nonhydrogen atoms, and a difference Fourier synthesis was used to determine the positions of the hydrogen atoms. We observed disorder at the location of perchlorate. Three oxygen atoms of perchlorate occupied two possible positions that are related by rotation around the bond between the chlorine atom and the remaining one oxygen atom; their multiplicities were 0.8 and 0.2, respectively. The value of R was reduced to 0.0648 after several cycles of block-diagonal least-squares calculations assuming anisotropic thermal parameters for nonhydrogen atoms and isotropic ones for hydrogen atoms. Figure 2 shows the molecular structure. The benzoxazine ring of this molecule is almost planar, though the C(2) atom slightly deviates from this mean plane. The methyl group at the C-3 position in the oxazine ring is axially oriented from the ring. The piperazine ring exists in the chair form, and the methyl group is equatorially oriented. The dihedral angle between the mean plane of this ring and the benzoxazine ring is 53°. The carboxyl group is an unionized form, and forms an intramolecular hydrogen bond with the ketone group [O(14)0(17) 2.525 A, O(14)H(017)1.684 A, H(017)0(17) 0.890 A, LO•••H-0156° ]. The crystal structure is
IR/Raman spectroscopy and DFT calculations of cyclic di‐amino acid peptides. Part III: comparison of solid state and solution structures of cyclo(L‐Ser‐L‐Ser)

B3-LYP/cc-pVDZ calculations of the gas-phase structure and vibrational spectra of the isolated molecule cyclo(L-Ser-L-Ser), a cyclic di-amino acid peptide (CDAP), were carried out by assuming C-2 symmetry. It is predicted that the minimum-energy structure is a boat conformation for the diketopiperazine (DKP) ring with both L-Beryl side chains being folded slightly above the ring. An additional structure of higher energy (15.16 kJ mol(-1)) has been calculated for a DKP ring with a planar geometry, although in this case two fundamental vibrations have been calculated with imaginary wavenumbers. The reported X-ray crystallographic structure of cyclo(L-Ser-L-Ser), shows that the DKP ring displays a near-planar conformation, with both the two L-Beryl side chains being folded above the ring. It is hypothesized that the crystal packing forces constrain the DKP ring in a planar conformation and it is probable that the lower energy boat conformation may prevail in the aqueous environment. Raman scattering and Fourier-transform infrared (FT-IR) spectra of solid state and aqueous solution samples of cyclo(L-Ser-L-Ser) are reported and discussed. Vibrational band assignments have been made on the basis of comparisons with the calculated vibrational spectra and band wavenumber shifts upon deuteration of labile protons. The experimental Raman and IR results for solid-state samples show characteristic amide I vibrations which are split (Raman:1661 and 1687 cm(-1), IR:1666 and 1680 cm(-1)), possibly due to interactions between molecules in a crystallographic unit cell. The cis amide I band is differentiated by its deuterium shift of ~ 30 cm(-1), which is larger than that previously reported for trans amide I deuterium shifts. A cis amide II mode has been assigned to a Raman band located at 1520 cm(-1). The occurrence of this cis amide II mode at a wavenumber above 1500 cm(-1) concurs with results of previously examined CDAP molecules with low molecular weight substituents on the C-alpha atoms, and is also indicative of a relatively unstrained DKP ring.
Mechanical Properties of Poly( L -Lactide) Films Controlled by Blending with Polyesters of Lignin-Derived Stable Metabolic Intermediate, 2-Pyrone-4,6-Dicarboxylic Acid (PDC)

Two kinds of polyesters containing 2-pyrone-4,6-dicarboxylic acid (PDC) moieties in poly(L-lactic acid) (PLLA) and poly(butylene succinate) (PBS) main chains were for the first time employed as an additive to PLLA for improvement of the mechanical properties. Solution casting of a mixture of PLLA and PDC polyesters provided the blend films, which were comprehensively characterized by thermal analyses, tensile measurements, and crystallinity evaluation. Differential scanning calorimetry measurements revealed that PDC incorporation into polymer main chain dramatically improves the miscibility with PLLA. PDC-incorporated PBS showed better miscibility than PDC-incorporated PLLA. Optical microscopy measurements also suggested the superior orientation of PDC-incorporated PBS over PDC-incorporated PLLA in the blend films. The fracture strain of the blend films could be linearly increased by a draw ratio in the region of low PDC polyester content. On the contrary, the fracture strain decreased at high PDC polyester content due to the restricted strain caused by the strong dipolar interactions between PDC-moieties. Elongation at break was significantly varied as a function of PDC polyester content, whereas tensile modulus was almost independent of the additive content and draw ratios. It is concluded that the blend films containing <10 wt% of PDC incorporated PBS as an additive show the best tensile property.
Soil Microscopy and Micromorphology

た は植生の 相違 に よ る腐植酸 の 生成環舞条件 の 違 い に 起 因 して い るの か 明らか で は な い . 一般的 に は,日本 の 黒 ボ ク 土 の 腐植酸の 型 が RF (相 対色度 :〔K ,。 /吸光度の 測定に 用 い た腐植酸溶液 30mL 当た りの O.5MKMnO4 消費量 (mL )〕× 1000)と Alog K (色調係数 : log K4e 。 − log K6 。 o , K は 波長 400 また は 600nm に お け る 吸光係数)の 違 い か ら Rp, P, B, A 型 の 4 型 に 類別され る こ とは 知 られ て い る 4). 著者 5・6) の 一人 は 桜島起源の 火山灰土 の 腐植酸の 生成 を 年代別に 調 べ ,火山灰 土 の 腐植酸 の 生成進行 過程が Rp → P → B−→ A 型 で あ る こ とを推定 した. しか し , こ の
Rapid and Simple Determination of Plasma and Erythrocyte MDA Levels in Prostate Cancer Patients by a Validated HPLC Method

Abstract We undertook the present study to develop a validated HPLC method for the determination of malondialdehyde (MDA) levels and to use this method for determination of MDA levels in patients with prostate cancer and benign prostatic hyperplasia. MDA levels were estimated in the erythrocyte and plasma sample of the 25 non‐metastatic prostate cancer patients, 36 benign prostatic hyperplasia (BPH) patients and 24 age‐ and sex‐matched healthy subjects (controls) in HP Chromatographic systems consisting of a Model Agilent 1100 Series. We report a very rapid and simple isocratic reversed‐phase HPLC separation of MDA in normal human plasma and erythrocytes without previous purification of the MDA‐TBA complex. All validation parameters were performed in our methods. Using this methods we have found elevated MDA in the plasma and erythrocyte of the prostate cancer group as compared to controls and BPH group. We have improved and validated an analytical HPLC method for determination of MDA in plasma and erythrocyte, which is simple to perform and having high sensitivity, specificity and substantial improvement in column life. This method has been successfully applied to determination of MDA levels in prostate cancer patients and offers an oportunity to further characterize the role of oxidative injury in the pathogenesis of this disease specifically.
ELECTROOSMOSIS THROUGH PORES WITH NONUNIFORMLY CHARGED WALLS

The movement of fluid through a charged capillary by the action of an electric field is analyzed in the case where the charge density on the capillary wall varies with axial position. The capillary's radius is assumed much greater than the Debye screening length of the fluid. Our results show that the mean fluid velocity within the capillary is given exactly by the classical Helmholtz equation with the local zeta potential replaced by the average zeta potential, determined by integrating the local value over the length of the capillary. If the magnitude of the local zeta potential exceeds the thermal potential (kT/e), the relationship between zeta potential and wall charge is nonlinear, so that the Helmholtz equation cannot be used to calculate the average charge from a measured electroosmotic flow or streaming potential. Although the mean electroosmotic velocity depends only on the average zeta potential, the fluid velocity field within the capillary is a strong function of the distribution of zeta poten.
Far-infrared Reflection Spectra, Optical and Dielectric Constants, and Lattice Vibrations of Some Fluoride Crystals

The reflection spectra of the crystals of the NaCl structure (LiF, NaF, and NiO), the fluorite structure (CaF2, BaF2, and CdF2), and the rutile structure (MgF2 and MnF2) were measured. The optical and dielectric constants were derived from the measured reflectivities using the Kramers-Kronig transformation. The absorption indices (k) for these crystals are rather large and the peak values of the imaginary dielectric constants amount to 30.0 or more. However, unlike the ferroelectric substances such as oxide perovskites and rutile, these fluoride crystals do not show any anomalous dielectric behaviour. From the real and imaginary dielectric constants e′(ν) and e″(ν), the transverse and longitudinal frequencies for the lattice modes are determined. These frequencies are reasonably interpreted on the basis of the crystal structures and satisfy the Lyddane-Sachs-Teller relation. The effective charge on the positive and negative ions and the force constant associated with the short-range elastic force against .
Effect of concentration, sorption, and microbial biomass on degradation of the herbicide fluometuron in surface and subsurface soils

The variation in adsorption and degradation of fluometuron was determined in soil collected from different depths (0-120 cm) of a Beulah silt loam soil profile. Microbial demethylation was the initial degradation step in both surface and subsurface soils, resulting in accumulations of demethylfluometuron (DMFM). After addition of 1500 ng/g of soil of fluometuron, degradation was adequately described by first-order kinetics. However, these kinetics did not describe degradation after addition of 85 ng/g of soil of [ 14 C-trifluoromethyl]fluometuron
Optical determination of the AlxGa1−xAs energy gap variation versus the Al concentration in MBE-grown samples

The authors have determined the variation of the AlGaAs energy gap (Eg) versus the aluminium concentration x. The x-values are determined by precise X-ray measurements and the values of Eg are deduced from photoluminescence experiments. They find the law, Eg(x)=Eg(O)+1.34x eV, for x<0.45 at T=2 K.
Protein crystal growth: An approach based on phase diagram determination

Abstract There is an increasing need to rationalize protein crystal growth, mostly carried out so far by trial-and-error. The phase rule gives the number of conditions necessary to specify the state of protein crystallization in equilibrium. Unsaturated and supersaturated regions are distinguished in phase diagrams. Examples of such diagrams for protein crystals are tabulated. To determine the phase diagrams reliably, the following items are discussed: (1) proper crystallization methods, (2) the length of time needed for establishing equilibrium, and (3) the importance of specifying the kind of solid state. Various crystallization methods are compared as to their effect on the solution system by using the phase diagrams, and the potential usefulness of the diagrams for crystallizing new proteins is discussed.
Mixing study in an inductive plasma reactor: Comparison between model calculations and experimental results

This study compares the predictions of a multicomponent reactive model of inductive plasma reactor mixing and experimental data obtained with the enthalpy probe technique. Central injection of two different gases, helium and nitrogen, into the core of an inductive (h.f.) plasma discharge permits us to analyze the influence of the nature of the central gas on the reactor's mixing patterns. This work highlights diffusion in a multicomponent situation. The model considers the dissociation of H2, present in the sheath gas. Cette etude compare les predictions d'un modele multicomposant d'un ecoulement reactif dans un reacteur a plasma inductif et des donnees experimentales obtenues par la technique de la sonde enthalpique. L'injection centrale de deux differents gaz, helium et azote, dans le centre de la decharge haute frequence (h.f.) permet d'analyser l'influence de la nature du gaz central sur les profils de melange dans le reacteur. Ce travail met en evidence la diffusion dans une situation multicomposante. Le modele considere la dissociation de l'H2 dans le gaz de gainage.
Depth Profiling of the Degree of Cure during the Photopolymerization of Acrylates Studied by Real-Time FT-IR Attenuated Total Reflection Spectroscopy

Real-time Fourier transform infrared attenuated total reflection (FT-IR/ATR) spectroscopy was used to study the depth profile of the conversion during photopolymerization reactions. The method is based on the UV irradiation of coatings of different thicknesses on the ATR crystal. Due to the finite depth of penetration of the infrared probe signal into the sample, conversion is analyzed only in a narrow layer at the bottom of the coating. The method was used to characterize the effect of photo-initiators on the depth of cure in acrylate coatings. The self-screening of a strongly absorbing morpholino ketone photo-initiator and the photobleaching of a bisacylphosphine oxide initiator are demonstrated. Moreover, depth profiling studies on the filter effect of UV absorbers and on the influence of pigmentation in white-pigmented systems will be reported.
A density functional-variational treatment of the hard sphere transition

A density functional-variational version of the Ramakrishnan-Yussouff theory of freezing is used to reconsider the problem of the hard sphere transition. This calculation differs from previous ones in that the solid density and the lattice constant are included as independent variational parameters. Besides giving an unambiguous method for determining the lattice constant of the solid this method allows the computation of the average density of defects in the solid. In addition, we use real, rather than Fourier, space techniques in solving the resulting equations. We argue that real space techniques are numerically more accurate for the narrow distributions found by these methods. Our results for the densities of the coexisting solid and liquid phases are very close to those given by molecular dynamics studies. The width of the solid density peaks is too small as is the case with previous calculations. The average density of defects has the correct sign but is much too large (ρD ⋍ -0·1) for a realistic solid.
Hindered Crack Propagation in Materials with Periodically Varying Young's Modulus—Lessons from Biological Materials

Many biological materials, such as bone, nacre or biosilica, are known to be both stiff and tough. Their structure is hierarchical and appears to be optimized at all levels of hierarchy to combine the properties of its primary components, which are a tough protein and stiff mineral. Bone, for example, is a nanocomposite and the deformation pattern is clearly hierarchical. In lamellar cortical bone, fibrillar units aggregate into laminate sheets, in analogy to plywood. This lamellar structure has a dramatic effect on fracture toughness. Nacre and biosilica are also layered structures where thin organic layers separate sheets of aragonite mineral and biosilica, respectively. The high toughness of such layered biological structures is intriguing and may serve as a model for artificial layered composites. A possible origin for the toughness in layered structures is the deflection of racks at weak interfaces. However, we know from theoretical fracture mechanics that a variation of the material properties alone (even without inherently weak interfaces) may result in a shielding or anti-shielding effect to the crack tip, which leads to a change of the crack driving force and the energy consumed by the fracture process. In the current work, we therefore analyse the driving force onto cracks propagating inside a material where the Young’s modulus varies in a periodic way in a given direction (perpendicular to the lamellae). We derive a simple design criterion to obtain laminate structures without driving force for crack propagation perpendicular to the lamellae. We consider a crack in a plane configuration of unit thickness with the crack tip located at the point P, see Figure 1. Globally, the material is assumed to be elastic with a constant Young’s modulus Efar and a Poisson’s ratio m far away from the crack tip P. Inside a circular region with the radius R, however, the Young’s modulus E varies in space. We assume that this variation is periodic in x-direction with an average value E0. The specimen is loaded by a stress ∑ in y-direction on the upper and lower parts of the boundary Cfar (indicated as “o” and “u” in Fig. 1). The crack flanks are assumed to be stressfree. The stress field r near the crack tip T is described by the classical “near-tip field” expressed in polar coordinates r,h and the stress intensity factor KI, for details see the fracture mechanics literature, e.g., Gross et al., Ch. 4.2. The specific elastic strain energy density r e 2 can be calculated analytically for constant E and plane stress or strain conditions as
High Electron Mobility Metal–Insulator–Semiconductor Field-Effect Transistors Fabricated on (111)-Oriented InGaAs Channels

Metal–insulator–semiconductor field-effect transistors (MISFETs) were fabricated on the (111)A surface of In0.53Ga0. 47As for the first time. Al2O3 gate dielectrics were formed by atomic layer deposition on sulfur-stabilized InGaAs surfaces. The MISFET on (111)A demonstrated channel mobility higher than that on (100), achieving more than 100% improvement with respect to Si even at a high surface carrier concentration.
Multiclass Determination of Phenolic Compounds in Different Varieties of Tomato and Lettuce by Ultra High Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry

Tomato and lettuce are main components of the Mediterranean Diet and it is important to know their content in phenolic compounds, considering they have beneficial effects on human health. In this work, more than 25 phenolic compounds were simultaneously analyzed by ultra-high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry, including phenolic acids, flavonols, and flavones. Several varieties of lettuce and tomato were evaluated and total phenolic content ranged from 68 to 212 mg/kg dry weight for lettuce, and from 341 to 1296 mg/kg dry weight for tomato, being the chlorogenic acid the compound detected at the highest concentration in both types of vegetables (lettuce from 9 to 126 mg/kg dry weight, tomato from 96 to 538 mg/kg dry weight), although in tomato the content of quercetin-3-O-rutinoside (from 29 to 460 mg/kg dry weight) was also important. On the other hand, the minor compounds detected were quercetin-3-O-derivate (up to 1 mg/kg dry weight) in tomato, and apigenin O derivate, luteolin C glucoside, and isorhamnetin 3-O-glucoside in lettuce. It was observed that the total phenolic content in the plum cherry tomato was significantly higher than in the other varieties, whereas in lettuce, the differences were not statistically different.
Crystal growth and p‐type conductivity control of AlGaN for high‐efficiency nitride‐based UV emitters

Microstructural analysis was carried out to clarify the compositional dependence of the generation of dislocations in AlxGa1-xN on an underlying AlN layer grown by metalorganic vapor phase epitaxy. When the film thickness is less than 1.5 μm, the threading dislocation density (TDD) increases with decreasing AlN molar fraction. However, when the film thickness exceeds 1.5 μm, TDD becomes maximum at x around 0.5. The growth of AlGaN on a grooved AlN template is effective in reducing TDD for all AlN molar fractions. TDD in AlGaN, which is close to binaries such as GaN and AlN, is a few 107 cm–2, while for the intermediate composition with x around 0.5, TDD is still at mid 108 cm–2. The activation energy of Mg in AlGaN is found to show a strong Mg concentration dependence with a negative one-third power law in Al0.25Ga0. 75N and Al0.5Ga0.5N as well as in GaN. Overdoping of Mg causes an increase in the activation energy for every composition; from this, the optimum Mg concentration for realizing the highest hole concentration can be deduced. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)