Miracle-dz/UniFAR-FTUs huggingface dataset:
“Living” Free Radical Photopolymerization Initiated from Surface-Grafted Iniferter Monolayers

A method for chemically modifying a surface with grafted monolayers of initiator groups, which can be used for a “living” free radical photopolymerization, is described. By using “living” free radical polymerizations, we were able to control the length of the grafted polymer chains and therefore the layer thickness up to ∼100 nm. Also, single-layer grafted block copolymers were obtained by subsequent polymerizations of styrene and methyl methacrylate monomers. The surface-grafted polymer and block copolymer layers were evidenced by direct imaging methods (transmission and scanning electron microscopy) and by indirect surface characterization methods (contact angle measurements, SFM, XPS, and IR). The ability to control the thickness of the grafted polymer as well as the synthesis of a grafted block copolymer layer in a well-defined manner affirms the “living” character of the surface-initiated free radical photopolymerization.
A modeling study of the nighttime radical chemistry in the lower continental troposphere: 1. Development of a detailed chemical mechanism including nighttime chemistry

We describe a detailed chemical mechanism (140 species, 440 reactions) representing atmospheric chemistry of the lower continental troposphere. We focus on chemical reactions potentially important for nighttime chemistry. The mechanism is based on the methods and concepts proposed by Carter [1990] for the development of the Statewide Air Pollution Research Center (SAPRC) mechanism to reduce the number of species and reactions. Peroxy radical chemistry is represented with chemical operators and secondary VOCs are lumped into a limited number of surrogate species. To account for new experimental data provided since the first formulation of the SAPRC mechanism, the whole set of reactions has been updated. Representation of peroxy radical chemistry has been modified to account for variability of organic peroxy radical-peroxy radical reaction rates. New chemical operators and new secondary species have been added to the mechanism to introduce reactions of alkenes with NO3. Reactions of alkenes with O3 have been largely revised to represent largest radical yields suggested by recent experimental studies. Chemistry of three biogenic compounds (isoprene, α-pinene and β-pinene) has been included. The mechanism is coupled to a two-layer box model (including anthropogenic and biogenic emissions of VOCs and NOx and dry deposition) in order to represent different chemical environments (from urban to rural cases). Comparisons with the SAPRC-99 mechanism show good agreements especially for high NOx regime. Results from the model are evaluated with typical observed concentrations in the different environmental cases with a special focus on the representation of radical species concentations. For both daytime and nighttime, the calculated OH and peroxy radical concentrations are within the range of available observed values although the model tends to overestimate HO2 concentrations in daytime. At night, OH concentrations are found to vary from 1 to 6×106 molecules cm−3 in the urban environment, 5×104 to 2×105 molecules cm−3 in polluted rural environments and 4×104 molecules cm−3 in remote environments.
Silicon Micromixers with Infrared Detection for Studies of Liquid-Phase Reactions

We present an integrated microchemical system that combines micromixing, a reaction channel, an IR detection region, and temperature control for monitoring and kinetic studies of liquid-phase reactions. The microdevices exploit the transparency of silicon to infrared radiation in most of the wavelength region of interest (4000−800 cm-1), the precise definition of microfluidic channels by deep reactive ion-etching, the high thermal conductivity of silicon, and the fusion bonding of silicon for fixed-path-length transmission cells. Two devices are considered, a simple T-shaped mixer and an efficient mixer with interleaving channels for rapid mixing. The first device is used to characterize IR transmission characteristics in silicon-based microreactors and to demonstrate the feasibility of monitoring exothermic reactions, the hydrolysis of propionyl chloride under isothermal conditions. The mixing characteristics of the second microreactor are evaluated experimentally by an acid−base reaction and predicted b.
Facile and practical synthesis of 2,6-dichloropurine

A facile and industrially viable process for preparation of 2,6-dichloropurine is reported. The process involves direct chlorination of xanthine with phosphorus oxychloride and a weak nucleophilic organic base, such as amidine, guanidine base, or Proton-Sponge.
Generation and in Situ Evaluation of Libraries of Poly(acrylic acid) Presenting Sialosides as Side Chains as Polyvalent Inhibitors of Influenza-Mediated Hemagglutination

This paper describes a simple, microscale method for generating and evaluating libraries of derivatives of poly(acrylic acid) (pAA) that present mixtures of side chains that influence their biological activity. The method is based on the one-step conversion of poly(acrylic anhydride) (pAAn) to linear polymers presenting multiple units of R on side chains, pAA(R): the polymers are obtained by ultrasonication of a suspension of pAAn and aqueous RNH2 contained in a 250-μL well of a microtiter plate. Using this method, derivatives of pAA having N-acetylneuraminic acid (NeuAc-L-NH2) as a side chain, pAA(NeuAc-L), were generated and assayed for ability to inhibit hemagglutination (HAI) of chicken erythrocytes by influenza virus A (X-31); the constant ( ) describing this inhibition is calculated on the basis of the concentration of NeuAc groups in solution, rather than the concentration of polymer molecules. Co-polymeric pAA(NeuAc-Ln; Ln = different linking groups) with a range of mole fractions of NeuAc-L-NH2 .
Evidence of Superexciplex in Dye Molecules

The excited state behavior of dye molecules under intense pulsed laser excitation appears to differ from that under low-power cw Xenon lamp excitation. In the latter case molecules absorb photons (from the lamp), go to the excited state and produce normal fluorescence. This is a one photon–one molecule process. But in the former case, two excited dye molecules combine together to form `superexciplex' and produce fluorescence and also amplified spontaneous emission (ASE) under intense, sharp, laser pulse excitation. This paper gives sufficient evidence verifying the existence of this new molecular species.
F27 Application of EDXRF to rapid screening for toxic elements in foods and asian patent medicines

The effectiveness of portable EDXRF (PEDXRF) was evaluated for field examination of foods. This presentation will describe results from a number of different case studies to illustrate the importance of PEDXRF in various FDA activities focusing on protecting consumers from contaminated foods and drugs, with specific focus on determination of toxic elements in foods, dietary supplements, Asian patent medicines, ceramicware, and related samples.
Identification and characterization of sorbed lutetium species on 2-line ferrihydrite by sorption data modeling, TRLFS and EXAFS

The Lu(III) sorbed species onto synthetic hydrous ferric oxide (HFO), commonly called ferrihydrite, has been identified. Characterization of the synthetic 2-line HFO shows that its synthesis is reproducible. Potentiometric titration of freshly synthesized HFO, modeled using the constant capacity model (κ1=0.5 F/m2) in the FITEQL code, yields a specific surface area Sa of 360±35 m2/g (N2-BET), a site density Nd of 2.86 sites/nm2 (concentration of hydroxyl groups, Ns=1.71×10-3 mol sites/g HFO), and acidity constants pKa1}int=6.37 and pKa2}int=9.25. Evaluation of chemical sorption data reveals the presence of two different Lu surface sorbed species, dependent on pH; a monodendate species forms at low pH and a polydentate species at pH>5. Satisfactory fits to the sorption data are obtained using a combination of monodentate and bidentate surface species. The combination of species is chosen, based on extended X-ray absorption fine structure (EXAFS) results. The sorption constants obtained from these fits are pKs=-1.89(±0.1) and pKs=-1.69(±0.1) for the monodentate species ≡FeOLu(H2O)52+ for fits to the pH edge and to the isotherm at pH°5.9, respectively. A value of pKs=3.69(±0.01) is found for the bidentate species ≡ Fe(O)2Lu(H2O)5+ for both fits. EXAFS analysis of sorption samples prepared at 4.5<pH<8 shows that Lu is surrounded by a single first shell of 7±1 oxygen atoms, at a distance of (2.30±0.01) Â in all samples. A second coordination shell of Fe neighboring atoms at a distance of (3.38±0.01) Â is observed for sorption samples pH≥5.5. This distance is associated with the formation of a bidendate complex with bonding via edge sharing to iron octahedra. The samples prepared at pH<5.1 show no Fe shell, as expected for monodentate coordination. No evidence for surface precipitation and no noticeable difference between wet paste and dried powder samples is found.
Hollow magnetic hydroxyapatite microspheres with hierarchically mesoporous microstructure for pH-responsive drug delivery

The hollow magnetic hydroxyapatite [Ca10(PO4)6(OH)2, HAp] microspheres with hierarchically mesoporous structures were hydrothermally fabricated using the similar structured CaCO3/Fe3O4 hollow microspheres as the sacrificial hard-templates. The magnetic property, in vitro biocompatibility, drug loading and release properties in different pH solutions were further investigated. The results showed that the magnetic properties for these biocompatible HAp microspheres could be well adjusted by modulation of the Fe3O4 amount, and the drug release rate increased apparently with the decrease of the pH values of the solution medium. The high drug-loading capacity and sustained drug release property suggest that the fabricated multifunctional hollow microspheres have great potential for magnetic and pH responsive drug-delivery applications.
Letter: Fe3+ spin transition in CaFe2O4 at high pressure

Abstract Single-crystal diffraction data collected for CaFe2O4 at high pressure reveal above 50 GPa an isosymmetric phase transition (i.e., no change in symmetry) marked by a volume decrease of 8.4%. X-ray emission spectroscopic data at ambient and high pressure confirm that the nature of the phase transition is related to the Fe3+ high-spin/low-spin transition. The bulk modulus K0 calculated with a Birch Murnaghan EoS (K′ = 4) is remarkably different [K0 = 159(2) GPa for CaFe2O4 “high spin” and K0 = 235(10) GPa for CaFe2O4 “low spin”]. Crystal structure refinements reveal a decrease of 12% of the Fe3+ crystallographic site volume. The geometrical features of the low-spin Fe3+ crystallographic site at high pressure (bond lengths, volume) indicate a relevant decrease of Fe3+-O bond lengths, and the results are in agreement with tabulated values for crystal radii of Fe3+ in high- and low-spin state. The reduced crystal size of Fe3+ in the low-spin state suggest that in lower mantle assemblages, Fe3+ partitioning in crystallographic sites should be strongly affected by the iron spin state.
Variation in band gap of lanthanum chromate by transition metals doping LaCr0.9A0.1O3 (A:Fe/Co/Ni)

Transition metal (Fe, Co, Ni) doped lanthanum chromate (LaCrO3) nanoparticles (NPs) were prepared by gel combustion method and calcinated at 800°C. Microstructural studies were carried by XRD and SEM/EDS techniques. The results of structural characterization show the formation of all samples in single phase without any impurity. Optical properties were studied by UV- visible and photoluminescence techniques. The energy band gap was calculated and the variation was observed with the doping of transition metal ions. Photoluminescence spectra show the emission peak maxima for the pure LaCrO3 at about 315 nm. Influence of Fe, Co, Ni doping was studied and compared with pure lanthanum chromate nanoparticles.
Selective Detection of Mercury (II) by Etching the Corners of Silver Triangular Nanoplates

ABSTRACT As confirmed by transmission electron microscopy, we found that Hg2+ has good affinity to etch the sharp corners of silver triangular nanoplates. The etching process induced an apparent absorption peak shift of silver triangular nanoplates from 580 to 530 nm. The shift degree of the absorption peak has a good linear relationship with the amount of Hg2+ added; thus, Hg2+ with a concentration from 0.2 to 1.5 µM can be quantitatively detected by measuring silver triangular absorption. The interaction between mercury and silver triangular nanoplates proposed here is also a new example of silver triangular nanoplate etching and important for explaining the etching mechanism.
Determination of micro-amounts of polythionates. Part XI. Spectrophotometric determination of two species of polythionates in their mixtures by cyanolysis and solvent extraction

Two species of polythionates, when present in their mixtures, have been determined by solvent extraction and spectrophotometry of the thiocyanate formed by cyanolysis of polythionates in both the absence and presence of copper(II) ions. When 1 mol of polythionate, SxO62–(where x= 4, 5 or 6) undergoes cyanolysis, x–2 mol of thiocyanate are formed in the presence of copper(II) ions; in the absence of Cu(II), x–3 mol of thiocyanate are formed. Therefore, the value of x in SxO62– can be evaluated. By using these values, the composition of solutions containing two species of polythionates was calculated. The present method can be applied to the determination of two species of polythionates when mixed in various ratios at a concentration level of micromoles per litre.
Temperature dependence of coercivity in MnBi

In contrast to most ferromagnetic materials, the low‐temperature phase of MnBi exhibits an increased coercivity, Hc, with temperature. μ0Hc has a value of 0.2 T at room temperature, and rises dramatically to a maximum value of 1.9 T at 550 K. In the temperature region near its maximum value, Hc is much larger than that of Nd‐Fe‐B and has a very‐low‐temperature coefficient. For this reason, MnBi has a great potential as a permanent magnet material at high temperatures. To describe the temperature dependence of Hc, we develop a hybrid domain‐wall pinning model which combines Hilzinger and Kronmuller’s scaling theory for an anisotropic domain wall with Gaunt’s theory of thermal activation. The hybrid model gives an excellent fit to the temperature dependence of Hc and provides good estimates for the domain‐wall energy and thickness over the temperature range studied.
The Crystal and Molecular Structure of Staurosporine, a New Alkaloid from a Streptomyces Strain

The molecular sturcture of staurosporine, an alkaloid from a Streptomyces strain, has been determined by means of an X-ray crystallographic analysis of its methanol solvate (C28H26N4O3·CH3OH). The crystals are monoclinic, with four formula units in a unit cell with dimensions of a=23.487(6), b=7.636(3), c=15.638(4) A, and β=116.71(5)°; the space group is C2. 2532 unique intensity data were collected on a four-circle diffractometer with LiF-monochromated Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using the 20 strongest reflections as the starting set; the 72nd random phase set led to the correct solution. The R value reached 0.047 by block-diagonal least-squares refinements. Staurosporine has been found to contain a unique dimeric indole structure. Because of the steric hindrance, the indolo[2,3-a]carbazole aromatic system in the molecule is slightly bent; the two terminal benzene rings make an angle of 7.5° with each other.
Optimization of Carbon Dioxide Fixation by Chlorella vulgaris Cultivated in a Membrane-Photobioreactor

In this paper, an enclosed membrane-photobioreactor was designed to remove CO 2 using Chlorella vulgaris. The performances of four reactors, which included the presented novel bioreactor, a draft tube airlift photobioreactor, a bubble column and a membrane contactor, were compared. The effects of the gas flow rate, light intensity, quality of the inner light source, and the characteristics of membrane module on CO 2 fixation were investigated. The results showed that the rate of CO 2 fixation in the membrane-photobioreactor was 0.95-5.40 times higher than that in the other three conventional reactors under the optimal operating conditions.
Pressure‐induced widths and shifts for the ν3 band of methane

Widths and shifts of methane lines perturbed by nitrogen are calculated using a complex‐valued implementation of Robert–Bonamy (RB) theory. The static intermolecular potential is described as a sum of electrostatic forces and Lennard‐Jones (6‐12) atom–atom terms, using literature values for all physical parameters. Vibrational dependence of the isotropic potential is obtained from the polarizability of methane assuming a dispersion interaction. The repulsive part of the Lennard‐Jones accounts for the greatest part of widths, while dispersion interactions are largely responsible for shifts. Although the average error between calculated and observed linewidths (up to J=8) is less than 6%, their distribution suggests the influence of interactions not described in the present theory.
Surficial Geology and Quaternary History of the Cleardale Area, Northwestern Alberta (NTS 84D/SW)

In this report, we describe the distribution, character and origin of surficial sediments in the Cleardale area (NTS 84D/SW) and discuss the Quaternary history of the region. The Cleardale area is located south of the Clear Hills, along the Alberta-British Columbia border, and comprises a broad lowland (450–750 m asl) that is incised by the Peace River. Three gravel sheets identified in the Cleardale area, each grading to different base levels, are attributed to three major cycles of fluvial aggradation and incision. These cycles are attributed to the evolution of regional braided river systems draining eastward from the Rocky Mountains since the Middle Tertiary. Widely dispersed till documents the advance of the Laurentide Ice Sheet across the Cleardale area during Late Wisconsinan glaciation. This advance covered the Cleardale area, including local uplands, and deposited one major till facies across much of the map area. These sediments provide insight into regional stratigraphy and landscape evolution in northwestern Alberta. During regional deglaciation, the Laurentide Ice Sheet retreated from the Cleardale area at ca.11 ka BP, exposing a broad lowland basin flanking the ancestral Peace River. Due to the down-drainage retreat of the Laurentide Ice Sheet, this basin became infilled by subaerial and glacial meltwater discharge that converged toward the ice margin, forming the western part of a regional proglacial lake termed Glacial Lake Peace. The extent of this former lake is demarcated by widespread glaciolacustrine sediments that cover the Cleardale area, up to approximately 780 m asl. Glacial Lake Peace progressively drained from the Cleardale area as the retreating Laurentide Ice Sheet exposed lower basins and outlets along the ancestral Peace River valley and surrounding lowlands to the east of the map area. Following lake drainage, Holocene fluvial processes incised through approximately 120 m of Quaternary sediments and 30 m into the underlying bedrock, forming the modern Peace River valley. Concomitant mass movement along the river valley and its tributaries is responsible for the widespread distribution of colluvium, which is a regionally significant surficial material that is a cause for infrastructure problems in the area. ERCB/AGS Open File Report 2010-11 (September 2010) • vii
Diffusion‐tensor MRI: theory, experimental design and data analysis – a technical review

This article treats the theoretical underpinnings of diffusion‐tensor magnetic resonance imaging (DT‐MRI), as well as experimental design and data analysis issues. We review the mathematical model underlying DT‐MRI, discuss the quantitative parameters that are derived from the measured effective diffusion tensor, and describe artifacts thet arise in typical DT‐MRI acquisitions. We also discuss difficulties in identifying appropriate models to describe water diffusion in heterogeneous tissues, as well as in interpreting experimental data obtained in such issues. Finally, we describe new statistical methods that have been developed to analyse DT‐MRI data, and their potential uses in clinical and multi‐site studies. Copyright © 2002 John Wiley & Sons, Ltd.
New heat-resistant polytriazole adhesives: investigation of adhesion of polytriazole resins to metals

Crosslinkable polytriazole resins (CPTs) were synthesized by 1,3-dipolar cycloaddition reaction between azide and alkyne monomers. Adhesion properties of CPTs and an epoxy resin to different metal substrates (copper, iron and aluminium) were evaluated in terms of the tensile lap shear strength. CPTs to aluminium and iron substrates have higher adhesion strength than those to copper substrates. The effect of temperature and humidity on adhesion strength has been investigated. The resin CPT-3 has the best heat resistance among CPTs, whose retentions of adhesion strength are approximate 80% at 150 °C and 70% at 180 °C to all the substrates. CPTs have high adhesion properties at high temperature and humidity as compared with an epoxy resin.
Use of the combined Lifshitz–van der Waals and Lewis acid–base approaches in determining the apolar and polar contributions to surface and interfacial tensions and free energies

Recently, a number of authors have been rearranging the various combinations and permutations of the different apolar and polar liquids with which contact angles can be measured on polar surfaces and in so doing have arrived at bizarre results. The rational order and procedures to be followed in the determination of the apolar and polar surface tension properties of polar materials, according to the van Oss-Chaudhury-Good components and parameters of the approach, are reiterated.
Radiation-induced changes in some SSNTDs

A comparative study of the effect of fast neutrons and alpha particles on the color changes of some solid state nuclear track detectors was performed. Samples from CR-39 diglycol carbonate and Makrofol polycarbonate were classified into two main groups. The first group was exposed to neutrons of energies in the range between 4.4 and 19.2 MeV, while the second group was irradiated with alpha particles of initial energies in the range between 5.1 and 34 MeV. The transmission of these samples in the wavelength range 200–2000 nm, as well as any color changes, was studied. A characteristic transmission band with different intensities in the wavelength range 200–2000 nm was observed when the samples were exposed to alpha particles, while the interaction of fast neutrons on these detectors, CR-39, may lead to the appearance of new transmission bands at some particular wavelengths. Using the transmission data, both the tristimulus and chromaticity coordinate values were calculated. In addition, the color differences between the non-irradiated sample and those irradiated with different neutron or alpha doses were calculated. The results indicate that both CR-39 and Makrofol detectors acquire color changes under fast neutrons or alpha particles irradiation, but the Makrofol detector has more response to color change than CR-39.
Rapid Synthesis, Characterization, and Physicochemical Analysis of Biopolymer-Based Graft Copolymers

Cellulose biofiber-based graft copolymers (cellulose-g-PMMA) were rapidly synthesized under the influence of microwave radiation (MWR) through free radical–induced graft copolymerization of methyl methacrylate (MMA) onto modified cellulosic biofibers in aqueous medium. The effect of different polymerization parameters such as reaction time, initiator molar ratio, monomer concentration, amount of solvent, and microwave power on grafting percentage was studied to get the maximum percentage of grafting (64.87%). XRD, FT-IR, SEM, and TGA were used to characterize the graft copolymers. The graft copolymers have been found to be more moisture resistant and also exhibited better chemical and thermal resistance.