Miracle-dz/UniFAR-FTUs huggingface dataset:
Biomimetic Polymer Nanostructures by Injection Molding

The nanometer scale topography of self-assembling structural protein complexes in animals is believed to induce favorable cell responses. An important example of such nanostructured biological complexes is fibrillar collagen that possesses a cross-striation structure with a periodicity of 69 nm and a peak-to-valley distance of 4-6 nm. Bovine collagen type I was assembled into fibrillar structures in vitro and sedimented onto solid supports. Their structural motif was transferred into a nickel replica by physical vapor deposition of a small-grained metal layer followed by galvanic plating. The resulting inverted nickel structure was found to faithfully present most of the micrometer and nanometer scale topography of the biological original. This nickel replica was used as a die for the injection molding of a range of different thermoplastic polymers. Total infection molding cycle times were in the range of 30-45 seconds. One of the polymer materials investigated, polyethylene, displayed poor replication of the biological nanotopographical motif. However, the majority of the polymers showed very high replication fidelity as witnessed by their ability to replicate the cross-striation features of less than 5 nm height difference. The latter group of materials includes poly(propylene), poly(methyl methacrylate), (poly(L-lactic acid), polycaprolactone, and a copolymer of cyclic and linear olefins (COC). This work suggests that the current limiting factor for the injection molding of nanometer scale topography in thermoplastic polymers lies with the grain size of the initial metal coating of the mold rather than the polymers themselves.
Conformal coating of TiO2 nanorods on a 3-D CNT scaffold by using a CNT film as a nanoreactor: a free-standing and binder-free Li-ion anode

A free-standing and binder-free electrode, which consists of a 3-D conductive scaffold and conformal TiO2 nanorods, is synthesized by using an interconnected CNT film as a nanoreactor. Such a conformal 3-D nanostructure can not only provide the electrodes with fast charge transportation and long-term structural integrity, but also eliminate the heavy metal current collector, polymer binder and conductive additive. The conformal CNT–TiO2 anode demonstrates exceptional electrochemical properties with high capacity, high rate capability and excellent cycling stability. It shows a charge capacity of 129 mA h g−1 after 1000 cycles at 10 C with a low capacity fade of 0.007% per cycle in a half cell. Meanwhile, the CNT–TiO2/LiFePO4 full cell exhibits superior capacity retention with a high Coulombic efficiency of approximately 100% during 400 cycles at 2 C. Such a 3-D conformal nanostructure is promising for application in high-performance energy storage.
Charge Transfer and Radical Ions in Photochemistry

Bimolecular photoreactions usually occur via several steps involving “complex-type” intermediates (excimers or exciplexes). Although physical chemists have investigated them for nearly thirty years (Forster, Weller), and postulated their existence in numerous publications, it is only in the last decade that evidence for an exciplex intermediate in cycloadditions (Caldwell) has been obtained, thereby establishing the link between spectroscopy and synthetic photochemistry. Since then, many investigations have confirmed the role of exciplexes as intermediates in bimolecular photoreactions. The photochemically induced charge transfer from a donor to an acceptor substrate determines not only the bond strengths in the primary exciplex but also influences—via the charge-transfer nature of the complex—the structure of the exciplex and thereby the selectivity of subsequent reactions. Such chemical processes between the donor and the acceptor prevent the reverse transfer of electrons, which usually results in regeneration of the starting materials, thereby only causing the dissipation of energy and occasionally—under specific conditions—the generation of molecules of the starting material in the triplet state. Ionic photodissociation also reduces the probability of a reverse transfer of electrons. This process, which produces solvated radical ions, is promoted by polar solvents and salt effects, particularly special salt effects. By this means it is possible to generate specific radical cations from, for example, alkenes and dienes and to study their reactions. Although in some areas, for example physical and biophysical chemistry, discussions of single electron transfer (SET) processes have long been found in the basic textbooks, organic chemistry lags far behind, although—and this is shown by the numerous recent publications—organic chemists are also aware of the fundamental importance of these processes. In this connection photochemistry plays a central role, since its instruments make it possible to carry out specific SET processes, to analyze them, and to use them in chemical reactions.
Selective reductions of nitroarenes to anilines using metallic zinc in near-critical water

A new procedure for the preparation of anilines (2) in good yield by reduction of the corresponding nitroarenes (1) using Zn in H2O at 250–300 °C is described. The procedure is powerful enough to reduce sterically hindered 2-nitro-m-xylene (1c) and is chemoselective for the NO2 groups in 1-chloro-2-nitrobenzene (1d) and 1-nitro-3-vinylbenzene (1h). The process involves the reduction of H2O by Zn to generate H2 followed by hydrogenation of the NO2 group catalysed by residual traces of Zn.
Facile Synthesis, Pure DFT Calculations, and PM3 Semiempirical MO Method Validation of Regiospecificity of Novel 1,4-Dihydropyrido[2,3-d]pyrimidine Derivatives

Reaction of 6-aminothiouracil (or uracil) with equimolar amounts of different ketones or diketones and the appropriate aromatic aldehydes afforded di- and tricyclic linear pyrido[2,3-d]pyrimidine derivatives 4, 6–12, 14, 16–18, 20, and 21, and pyrimido[4,5-b]quinoline derivatives 15 and 19 in good yields. The regiospecificity, which led to the formation of compound 4 not 5, was validated using ab initio at the HF/6–31 G+(d,p) level and pure density functional theory (DFT) calculations using BLYP energy functional and the basis set DNP via studying the thermodynamics of their possible conformers and regioisomers. In addition, the total energy of the transition state was calculated for compounds 12 and 13 to determine whether the reaction products were thermodynamically or kinetically controlled. Hence, the linear structures and the regiospecificities of the reactions for the structures reported in this article were established by elemental analysis, spectral data, ab initio calculations, pure DFT, and PM3 parameters.
Shannon entropy of chemical changes: SN2 displacement reactions

The Shannon entropies along the intrinsic reaction coordinates (IRC) of two SN2 reactions were calculated at the RHF/6-31++G** level. The resulting entropic profiles were compared with the corresponding energy profiles. The Shannon entropy profiles in position and momentum space, as well as their sum, show interesting features about the bond forming and breaking process that are not apparent from the conventional reaction energy profile. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 77: 376–382, 2000
Electrochemically‐Induced Deposition of Amine‐Functionalized Silica Films on Gold Electrodes and Application to Cu(II) Detection in (Hydro)Alcoholic Medium

Well-adherent amine-functionalized porous silica films have been deposited on gold electrodes by combining the self-assembly technology, the sol–gel process, and the electrochemical modulation of pH at the electrode/solution interface. A partial self-assembled monolayer of mercaptopropyl-trimethoxysilane (MPTMS) was first formed on disposable gold electrodes from recordable CDs (Au-CDtrodes). The so pretreated MPTMS-Au-CDtrodes were immersed in a stable sol solution (pH 3) containing (3-aminopropyl)-triethoxysilane (APTES) and tetraethoxysilane (TEOS). Polycondensation of the APTES and TEOS precursors was then achieved by applying a negative potential for a given period of time to generate a local pH increase at the electrode/solution interface and promote the deposition of the amine functionalized silica film adhering well to the electrode surface owing to the MPTMS monolayer acting somewhat as a “molecular glue”. Various parameters affecting the electrodeposition process have been studied and the film permeability to redox probes in solution was characterized by cyclic voltammetry. The amine-functionalized silica film electrodes were then applied to the preconcentration of copper(II) species prior to their electrochemical detection by anodic stripping differential pulse voltammetry. Getting high sensitivity has however required the application of an electrochemical pre-activation step as the majority of the organo-functional groups were in the form of ammonium moieties (because the film was prepared from an acidic sol). This was achieved by applying a sufficiently negative potential to the electrode surface to reduce protons and increase consequently the amine-to-ammonium ratio within the film and, thus, the efficiency of the precocentration process. The resulting device was then optimized for copper(II) determination in hydroalcoholic medium, giving rise to a linear response in the 0.1–10 μM concentration range.
Multistability and hysteresis in an industrial ammonia reactor

A model for an industrial ammonia reactor was studied with nonlinear-analysis tools. This model was recently considered to explain an industrial incident involving the onset of sustained oscillations due to a sudden decrease in the reactor pressure. The analysis was based on the bifurcation diagrams. Both multistability and hysteretic behaviors described here can be useful for an effective plant design, as well as for an adequate plant control and operation.
Organoselenide as a Novel Ionophore for a Silver-Selective Membrane Electrode

Abstract Three selenium-containing compounds, diphenyl selenide, benzyl phenyl selenide and dibenzyl selenide were used as neutral carriers to make a Ag+-selective membrane electrode. All three compounds exhibited higher sensitivity to Ag+ than the corresponding sulfides and ethers. The highest sensitivity was obtained by dibenzyl selenide and an electrode constructed using this carrier and bis(l-butylpentyl) adipate as a membrane solvent in a poly(vinyl chloride) membrane matrix exhibited a near-Nernstian response to Ag+ in the concentration range from 1 x 10−5 to 1 x 10−2 M with a slope of 52 mV per concentration decade. The lower limit of detection was around 1 μM. The ion selectivity of this electrode for Ag+ was over 104 times that for other metal cations. Dibenzyl selenide and Ag+ interactions were examined by 1H-NMR spectroscopy.
The oxidation of norbornadiene and some derivatives using Pseudomonas sp.

Norbornadiene is oxidized by a Pseudomonad to give the diol (2)(35%) while 7-phenylnorbornadiene furnishes 3-norbornadienylcyclohexa-3,5-diene-1,2-diol (10)(41%) on incubation with the same organism; cyclization reactions involving the acetonide (15) have been investigated.
Understanding Volatility: An Analysis of the Stock Market Return-Variance Correlation

3 Introduction . 4 Defining Volatility . 4 VIX . 4 Introduction . 6 Volatility Feedback Effect . 7 International Evidence . 8 Extreme Cases . 9 Empirical Test . 11 Leverage Effect . 12 Investor Behavior . 15 Analysis . 16 Historical Analysis . 23 Implications . 24 Conclusion . 26 Appendix . 28 Works Cited . 31
Bis(4-ethylanilinium) 4,5-dichlorophthalate

The crystal structure of the title compound, 2C8H12N+·C8H3Cl2O42−, is stabilized by nine N—H⋯O and four C—H⋯O hydrogen bonds, and also by C—H⋯π inter­actions. Intra­molecular C—H⋯O hydrogen bonds form C(6) chains along the c axis. This chain and the other hydrogen bonds generate edge-fused [R12(6)R12(4)R43(10)R12(4)R32(9)] motifs in a three-dimensional network. The dihedral angles between the carboxylate anion and the cation aromatic ring planes are 75.90 (2) and 68.15 (2)°, and the dihedral angles between the carboxyl­ate groups and the anion aromatic ring plane are 13.72 (3) and 84.64 (3)°.
ANTIOXIDATIVE POTENTIAL OF EDIBLE WILD BULGARIAN FRUITS

Aqueous and aqueous-methanolic extracts from six Bulgarian wild edible fruits have been studied for their antioxidant activity and polyphenol content. The antioxidant activity was measured by ABTS cation radical decolorization assay and presented as Uric Acid Equivalents (UAE) per gram dry weight. The content of total phenolics in the extracts was determined using Folin- Ciocalteu reagent and calculated as Quercetin Equivalents (QE) per gram dry weight. The fruits from Sambucus ebulus showed the highest antioxidant activity of their aqueous (1005.38 ± 18.51 µmol UAE/g) and aqueous-methanolic extracts (779.65 ± 51.54 µmol UAE/g). In both types of extracts the antioxidant activity decreased as following: Sambucus ebulus > Crataegus monogyna > Rosa canina > Berberis vulgaris > Vaccinium myrtillus > Prunus spinosa. The fruits with highest polyphenol content were S ebulus fruits − 73.73 ± 0.57 mg QE/g in aqueous extracts and 68.27 ± 1.93 mg QE/g in aqueous-methanolic extracts. A high degree of positive correlation was established between the polyphenol content and the antioxidant activity. The correlation coefficients were R = 0.961 for aqueous and R = 0.958 for aqueous- methanolic extracts. The excellent positive correlations indicate that polyphenols are the main factor contributing to the antioxidant potential of the fruits studied.
Remote sensing of photosynthetic-light-use efficiency of a Siberian boreal forest

Abstract The relationship between a physiological index called the photochemical reflectance index (PRI) and photosynthetic light-use-efficiency (LUE) of a Siberian boreal forest during the winter–spring transition, or green-up period, was investigated in 2000. During this time the photosynthetic apparatus was considered under stress as a result of extremes of temperature (from −20 to 35 °C) coupled with a high radiation load. Reflectance measurements of four stands were made from a helicopter-mounted spectroradiometer and PRI was calculated from these data. Eddy covariance towers were operating at the four stands and offered a means to calculate LUE. A significant linear relationship was apparent between PRI, calculated from the helicopter spectral data, and LUE, calculated from the eddy covariance data, for the four sites sampled. Reflectance measurements were also made of a Scots pine stand from the eddy covariance tower. Needles were also sampled during the time of spectral data acquisition for xanthophyll pigment determination. Strong linear relationships were observed among PRI, the epoxidation state of the xanthophyll cycle (EPS) and LUE over the green-up period and the diurnal cycle at the canopy scale.
The effect of magnesium hydroxide, hydromagnesite and layered double hydroxide on the heat stability and fire performance of plasticized poly(vinyl chloride)

Emulsion grade poly(vinyl chloride) was plasticized with 100 phr of diisononyl phthalate and filled with 30 phr of different hydrated filler-type flame-retardant additives. Static heat stabilities were determined at 200°C by following the time dependence of hydrogen chloride evolution. Fire-retardant performance was studied with a cone calorimeter at a radiant flux of 35 kW m−2. The layered double hydroxide outperformed the other fillers with regard to improving static heat stability and also with respect to most fire-retardant performance indices.
Biosorption of a Basic Dye from Aqueous Solutions by Euphorbia rigida

Abstract In this study, the biosorption of Basic Blue 9 (BB9) dye from aqueous solutions onto a biomass of Euphorbia rigida was examined by means of the initial biosorbate concentration, biosorbent amount, particle size, and pH. Biosorption of BB9 onto E. rigida increases with both the initial biosorbate concentration and biosorbent amount, whereas decreases with the increasing particle size. The experimental data indicated that the biosorption isotherms are well‐described by the Langmuir equilibrium isotherm equation at 20, 30, and 40°C. Maximum biosorption capacity was 3.28×10−4 mol g−1 at 40°C. The biosorption kinetics of BB9 obeys the pseudo‐second‐order kinetic model. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated to estimate the nature of biosorption. These experimental results have indicated that E. rigida has the potential to act as a biosorbent for the removal of Basic Blue 9 from aqueous solutions.
MODEL OF UNSTEADY n -OCTANE DROPLET BURNING IN HIGH-TEMPERATURE STREAMS

Unsteady burning, internal heating, and modeling comparison of an n-octane fuel droplet in high-temperature flows are studied numerically. In the developed numerical method, the governing equations of the gas and the liquid phases are fully solved and linked at the interface. In addition, a moving grid system and the particle deceleration are also considered to account for the droplet regression and impact of drag force. The obtained results show that the convective droplet is ignited with a wake flame after a heating-up period. With increasing time the relative velocity between the droplet and surrounding flow becomes smaller due to the drag. As a result, the flame changes from a wake type, through a transition type, and eventually to an envelope type. With regard to the droplet interior, internal heat transfer is always dominated by internal circulation and unsteady heating prevails over the entire droplet lifetime. The vaporization fluxes predicted in terms of various quasi-steady models are also compared with the present solution. The quasi-steady analysis, omitting the initial droplet heat-up process, fails to predict the flame configurations and vaporization flux in the initial period of the droplet lifetime. Nevertheless, the role played by the initial unsteadiness on droplet vaporization is important only in a short period relative to the whole droplet lifetime. When the envelope flame develops around the droplet, the predictions by the quasi-steady models are in good agreement with the transient solution, except for the vaporization model. Furthermore, if the droplet undergoes a sudden drop in ambient temperature, it reveals that the dual solution of the quasi-steady model enables us to predict the droplet vaporization rate and flame configuration well.
Development of SYBR‐Green Real‐Time PCR and a Multichannel Electrochemical Immunosensor for Specific Detection of Salmonella enterica

Abstract The objective of the present work was to develop and evaluate an SYBR Green real time polymerase chain reaction (PCR) method for the specific detection of Salmonella spp in broth cultures and meat samples experimentally contaminated. Also, a simple and rapid multichannel electrochemical immunosensor (MEI) for this pathogen is under study. The PCR was carried out using primers ttr6 and ttr4 for the amplification of a highly conserved DNA region (ttr sequence) specific for all Salmonella serovars. A boiling step, for the extraction of DNA, was combined with a real time PCR method based on the double‐stranded DNA (dsDNA) binding dye SYBR Green. The standard curve constructed using the mean threshold cycle and various concentrations of S. enteritidis (ranging fron 102 to 108 CFU mL−1) showed good linearity (R2=0.999) with the minimum level of detection of 102 CFU mL−1. The experiments were conducted analyzing 30 Salmonella strains and 20 non‐Salmonella strains. All Salmonella serotypes tested were ttr‐positive and all other bacteria yielded no amplification products. The specificity of the reaction was confirmed by the melting temperature (Tm) of the amplicon obtained (Tm=80.1±0.1). To verify the effectiveness of the assay, experiments were conducted on experimentally contaminated samples, which were also analyzed for comparison by the standard cultural method. A multichannel electrochemical immunosensor for detection of Salmonella also was developed. It consists of a disposable screen‐printed sensor array, coupled with a multichannel pulse monitor, which was assembled as an immunosensor through the use of specific monoclonal (MAb) and polyclonal (PAb) antibodies in a sandwich format. The limit of detection was calculated to be 2×106 UFC mL−1 with a working range between 5×106 to 5×108 UFC mL−1 and a total analysis time of about 3 h. This immunoelectrochemical system is economical, rapid, and easy to use but it is still under development in order to improve its analytical performance.
Drying Rates in Resin Treatment of Lyocell Fabrics

Many properties of lyocell fibers are markedly different from those of other cellulosic fibers. Hence, it is necessary to study Lyocell wet processing to determine and characterize variables that have a significant influence on the properties of finished products. At the Christian-Doppler Laboratory, we are conducting an investigation to characterize resin finishing of Lyocell. As a part of this investigation, we are studying the influence of drying conditions in the pad-dry-cure process on the performance properties of the finished products. The influence of the drying rate on the distribution of crosslinking reagents in treated lyocell fabric samples is similar to that reported for other cellulosics, but the effect of reagent distribution on the performance properties of treated lyocell is different from that reported for other cellulosics. These differences may stem from changes that occur in lyocell fibers with moisture sorption.
Study of PEFCs by AC Impedance, Current Interrupt, and Dew Point Measurements I. Effect of Humidity in Oxygen Gas

The effect of humidity in oxygen gases on the performance of a polymer electrolyte fuel cell (PEFC) was examined by using linear current sweep (current-voltage), current interrupt, and ac impedance methods in combination with temperature variations of cathode humidifiers. The total resistance of the membrane increased about 3.4 mΩ by the temperature change of the cathode humidifier from 80 to 35°C. The results of electrochemical analysis showed that one-third of the total resistance change was due to the membrane resistance and almost the same amount could be attributed to the charge-transfer resistance. The measurements of dew points in hydrogen and oxgen gases at the entrance and the exit of the fuel cell made it clear that the water transport was sensitively affected by the temperatures of humidifiers of the cathode side. In the case of equal temperatures, water migrated from the cathode side to anode side, while the water movement in the reverse direction took place at the cathode humidifier temperature lower than the anode.
The importance of dissolved organic phosphorus to phosphorus uptake by limnetic plankton

The substrate [cx-~~P]ATP was used to represent the available fraction of the dissolved phosphomonoester (PME) pool and to measure its rate of assimilation by freshwater plankton in systems of low phosphorus availability. We compared [32P]ATP uptake to inorganic 32P0,3- uptake. The upper bounds to the pool sizes of POd3- and PME were estimated with Rigler bioassays, and these values, together with the uptake constants at ambient substrate concentrations, permit comparison of the uptake of organic and inorganic P by limnetic plankton. Affinity of the plankton for both substrates was high, and the estimated flux rates from both pools were similar, demonstrating that PME contributes significantly to total P uptake. We tested the hypothesis that algae > 1 km preferentially assimilate P from PME but observed that the 0.2-1-lrn size fraction dominates uptake of P from either source at ambient concentrations. The specific flux of P from PME into the 1-12qm size fraction was often as high as that into the 0.2-l-pm fraction, but plankton > 12 pm typically incorporate ~5% of the P from either source.