Miracle-dz/UniFAR-FTUs huggingface dataset:
Enzyme mediated synthesis of phytochelatin-capped CdS nanocrystals

We reported the enzyme mediated synthesis of CdS nanocrystals by immobilized phytochelatin synthase, which converts glutathione into the metal-binding peptide phytochelatin (PC). Formation of CdS nanocrystals were observed upon the addition of CdCl2 and Na2S with PC as the capping agent. By varying the reaction times, different compositions of PCs (form PC2 to PC3) can be synthesized, resulting in the formation of highly stable nanocrystals with tunable sizes (from 2.0 to 1.6 nm diameter). This approach may be generalized to guide the in vitro self assembly of a wide range of nanocrystals with different compositions and sizes.
Chemical and optical properties of carbon-doped TiO2: A density-functional study

The conflict of understandings on experimental results about chemical and optical properties of C-doped TiO2, which has been overlooked for a long time but is essential for studies of the basic properties of this material, is unraveled. It is shown that in anatase TiO2 the doped C and O atoms can easily couple with each other at typical synthesis conditions due to the large binding energy and small energy barrier, while in rutile phase, the coupling can hardly occur. The characteristics of the structures are elaborated in detail, which provides insights into the chemical, optical, and magnetic properties of C-doped TiO2.
Fabrication of novel colloidosome microcapsules with gelled aqueous cores

Novel colloidosome microcapsules with aqueous gel cores and integral shells of polymeric colloid particles have been prepared and characterized. Our method is based on templating water-in-oil emulsions stabilized by polystyrene (PS) latex particles, followed by gelling of the aqueous phase with a suitable hydrocolloid. The obtained microcapsules were transferred into water after dissolving the oil phase in ethanol and multiple centrifugation–washing with ethanol and water. The presence of an aqueous gel core was found to be crucial for the structural integrity and mechanical stability of the obtained colloidosome microcapsules. The effect of the oil type on the final structure of the colloidosome membrane was also studied. It was demonstrated that by using an appropriate oil, the particles within the colloidosome monolayer can be partially or completely swollen which allows direct control over the membrane pore size and its permeability. Such colloidosome microcapsules may find applications as delivery vehicles for controlled release of drugs and cosmetic or food supplements.
Reaction of 1,2,4-triazolo [4,3-a] pyridine with dimethyl acetylenedicarboxylate: new structures and mechanisms

Reaction of 1,2,4-triazolo[4,3-a] pyridine (1) with dimethyl acethylenedicarboxylate gives the pyrimidone (10), the pyrazole (6), and the 1 : 2-adduct (7); reaction mechanisms, which include a [1,5] CN shift from nitrogen to carbon, are proposed, and two earlier structures for products of this reaction are corrected.
Nature and stability of ice X

A study of pressure effects on the vibrational frequencies of ice X is performed to shed light on the existence and stability of this phase. The analysis reveals: (i) its stability range, (ii) the soft phonon nature of the transition at high pressures to the Pbcm structure proposed by Benoit et al. (M. Benoit, M. Bernasconi, P. Focher, and M. Parrinello, New high-pressure phase of ice, Phys. Rev. Lett. 76 (1996), pp. 2934–2936. ) and (iii) the phonon collapse associated with the dynamical disordered structure at low pressures. Additionally, a topological analysis of the electron localization function and the electron density through the atoms-in-molecules formalism clarifies the chemical nature of ice X. †This paper was presented at the XLVIth European High Pressure Research Group (EHPRG 46) Meeting, Valencia (Spain), 7–12 September, 2008.
Improving the contact resistance at low force using gold coated carbon nanotube surfaces

Investigations to determine the electrical contact performance under repeated load cycles at low force conditions for carbonnanotube (CNT) coated surfaces were performed. The surfaces under investigation consisted of multi-walled CNT synthesized on a silicon substrate and coated with a gold film. These planar surfaces were mounted on the tip of a PZT cantilever and contacted with a hemispherical Au plated probe. The dynamic applied force used was 1mN. The contact resistance (Rc) of these surfaces was investigated with the applied force and with repeated loading cycles performed for stability testing. The surfaces were compared with a reference Au-Au contact under the same experimental conditions. This initial study shows the potential for the application of gold coated CNT surfaces as an interface in low force electrical contact applications.
Preliminary nitrogen, phosphorus, potassium, calcium and magnesium DRIS norms and indices for apple orchards in Canterbury, New Zealand

Abstract Diagnosis and Recommended Integrated System (DRIS) norms and indices for N, P, K, Ca and Mg were developed for apple trees in Canterbury, New Zealand, based on surveys of nutrient levels of apple leaves in field experiments before and after N and K fertiliser applications and in four orchard surveys over a period of three years. Comparisons were made between calculated norms based on mean sufficiency nutrient levels and published norms. Results obtained showed that calculated norms and indices from sufficiency range provide a good indication of the order of apple nutrient requirements. High N and low Ca were identified as major nutrient problems. The best period for sampling leaves for nutrient analysis is at 3 to 5 months after blossom (i.e., December to January in New Zealand).
FIELD-INDUCED BROADENING OF OPTICAL ABSORPTION IN INP-BASED QUANTUM WELLS WITH STRONG AND WEAK QUANTUM CONFINEMENT

We have studied in detail the field‐induced broadening of optical absorption in InP‐based quantum well (QW) structures with both strong and weak quantum confinement. Electroabsorption process in the QW structures with the weak confinement is modeled taking both excitonic absorption and subband‐to‐subband absorption into account. It is theoretically shown that the spectral broadening associated with the applied electric fields is largely due to the quantum confinement of the barrier structures. In the InP‐based QW structures absorption spectra, calculated assuming their broadening is due solely to carrier tunneling, successfully explain the measured photocurrent spectra.
Nanoscale patterning of an organosilane monolayer on the basis of tip‐induced electrochemistry in atomic force microscopy

An organosilane trimethylsilyl (TMS) monolayer prepared on silicon (Si) substrate by chemical vapor deposition was successfully applied as a self‐developing resist for atomic force microscope (AFM) lithography. The thickness of the monolayer was less than 1 nm. This resist was locally degraded due to electrochemical reactions induced in the junction between a conductive AFM probe and a Si–TMS sample. The generated pattern on the sample was then transferred to the Si substrate by chemical etching using the degraded region as an etching window. Degradation of the monolayer proceeded with both positive and negative sample biases. However, the absolute values of the voltage at which the probe‐scanned region began to show etching were +3.0 for Vs>0 and −5.0 V for Vs<0, in a 60% relative humidity air atmosphere. Faster patterning was achieved through increased current flow by applying a higher bias voltage. A 500 μm/s line drawing at Vs=+20.0 V with 2–3 nA was obtained. The number of injected electrons was esti.
Translational and rotational motion in molecular liquids: A computer simulation study of Lennard–Jones ellipsoids

In order to understand the translational and rotational motion in dense molecular liquids, detailed molecular dynamics simulations of Lennard-Jones ellipsoids have been carried out for three different values of the aspect ratio kappa. For ellipsoids with an aspect ratio equal to 2, the product of the translational diffusion coefficient (D-T) and the average orientational correlation time of the l-th rank harmonics (tau(lR)), converges to a nearly constant value at high density. Surprisingly, this density independent value of D-T tau(lR) is within 5% of the hydrodynamic prediction with the slip boundary condition. This is despite the fact that both D-T and tau(lR) themselves change nearly by an order of magnitude in the density range considered, and the rotational correlation function itself is strongly nonexponential. For small aspect ratios (kappa less than or equal to 1.5), the rotational correlation function remains largely Gaussian even at a very large density, while for a large aspect ratio (kappa greater than or equal to 3), the transition to the nematic liquid-crystalline phase precludes the hydrodynamic regime. Thus, the rotational dynamics of ellipsoids show great sensitivity to the aspect ratio. At low density, tau(lR) goes through a minimum value, indicating the role of interactions in enhancing the rate of orientational relaxation. (C) 1997 American Institute of Physics. [S0021-9606(97)50142-5].
Study on biological safety of spider silk protein bilayer vascular scaffold

The spider silk protein bilayer vascular scaffold (SSPBVS) based on RGD-recombinant spider silk protein (pNSRl6), gelatin (Gt), chitosan (CS), and polycaprolactone (PCL) was prepared using electrospinning method. To evaluate the biological safety of SSPBVS, which has potential application in tissue engineering blood vessel, acute toxicity test, skin irritation test, skin sensitization test, single cell gel electrophoresis test, pyrogeneous test, chromosomal aberration test, and micronucleus test were carried. The results demonstrated that distribution of scaffold fiber was dense, with high porosity and no adhesion phenomenon was found. When Mesenchymal stem cells (MSCs) were cultured with vascular scaffold extract, they proliferated rapidly with fusiform morphology. Statistics showed that there was no significant difference in rat organ index between SSPBVS extract group and control group. SSPBVS extract only had slight irritation on the standard deviation (SD) rat skin, and no sensitization was found. SSPBVS extract did not initiate DNA damage of MSCs, and nuclear DNA was complete. Body temperature elevation value of SD rat in SSPBVS extract group was less than 0.2 °C. The SSPBVS extract did not cause gene mutation of the chromosome. PCE ratio of SSPBVS extract group was 3.1 ± 1.5 ‰. This study suggested that SSPBVS did not bring significant toxic effect on MSCs in vitro and had potential as scaffold in tissue engineering blood vessel.
Electrochemical nanostructured biosensors: carbon nanotubes versus conductive and semi-conductive nanoparticles

The aim of this work was to demonstrate that various types of nanostructures provide different gains in terms of sensitivity or detection limit albeit providing the same gain in terms of increased area. Commercial screen printed electrodes (SPEs) were functionalized with 100 µg of bismuth oxide nanoparticles (Bi2O3 NPs), 13.5 µg of gold nanoparticles (Au NPs), and 4.8 µg of multi-wall carbon nanotubes (MWCNTs) to sense hydrogen peroxide (H2O2). The amount of nanomaterials to deposit was calculated using specific surface area (SSA) in order to equalize the additional electroactive surface area. Cyclic voltammetry (CV) experiments revealed oxidation peaks of Bi2O3 NPs, Au NPs, and MWCNTs based electrodes at (790 ± 1) mV, (386 ± 1) mV, and (589 ± 1) mV, respectively, and sensitivities evaluated by chronoamperometry (CA) were (74 ± 12) µA mM−1 cm−2, (129 ± 15) ±A mM−1 cm−2, and (54 ± 2) ±A mM−1 cm−2, respectively. Electrodes functionalized with Au NPs showed better sensing performance and lower redox potential (oxidative peak position) compared with the other two types of nanostructured SPEs. Interestingly, the average size of the tested Au NPs was 4 nm, under the limit of 10 nm where the quantum effects are dominant. The limit of detection (LOD) was (11.1 ± 2.8) ±M, (8.0 ± 2.4) ±M, and (3.4 ± 0.1) ±M for Bi2O3 NPs, Au NPs, and for MWCNTs based electrodes, respectively.
Aptamer-Based Inhibition Assay for the Electrochemical Detection of Tobramycin Using Magnetic Microparticles

The detection of small molecules using aptamers is not straightforward when the induced fit triggered by the analyte is also small. Herein a labeling strategy is explored for the voltammetric detection of the antibiotic tobramycin using magnetic microparticles (MPs). A competition between MPs-immobilized tobramycin and free tobramycin for the limited amount of the biotinylated-aptamer was established. The addition of the enzymatic conjugate and the substrate generated a product that was electrochemically oxidized on screen-printed carbon electrodes. The analytical signal was proportional to the antibiotic concentration from 5–500 µM and the reproducibility was 5.7 %. The assay selectivity was also studied.
Electrochemistry at Lipid Monolayer-Modified Liquid−Liquid Interfaces as an Improvement to Drug Partitioning Studies

The drug partitioning between membrane and solution has traditionally been approached with bulk thermodynamic models, such as the octanol−water partitioning system. This neglects the orientational and compositional order in biological membranes. In the present study, electrochemistry at a Langmuir−Blodgett phospholipid monolayer-modified liquid−liquid interface has been employed to study the specific interactions between ionized drugs and phosphatidylcholine layers. To this end, AC voltammetric experiments and theoretical modeling accounting for the adsorption of the electroactive species have been carried out. The results point to a mechanism of charge transfer involving an adsorption step. This highlights the fact that in predicting biological activity of drugs, dynamic aspects and chemical interactions need to be considered.
The Sol−Gel Method: A New Way to Reversed Phase Materials. Synthesis and Characterization by Solid-State NMR Spectroscopy

The sol−gel method offers a new approach for the synthesis of reversed-phase materials used in chromatography. Co-condensation of different amounts of tetraethoxysilane (Q0) and trifunctional alkylsilanes (T0) leads to novel polymer networks with new properties, for example, high degrees of cross-linking and high ligand densities. Two different steps in synthesis, the sol−gel transition and the precipitation of homogeneous sols, are discussed. These new materials were studied by 13C and 29Si solid-state NMR spectroscopy. Further characterization was performed by BET measurements and scanning electron microscopy.
Gelatin as a new humidity sensing material: Characterization and limitations

The goal of this work is to assert the utility of collagen and its denatured counterpart gelatin as cost-effective alternatives to existing sensing layers comprised of polymers. Rather than producing a material that will need to be discarded or recycled, collagen, as a by-product of the meat and leather industry, could be repurposed. This work examines the feasibility of using collagen as a sensing layer. Planar electrodes were patterned with lift-off process to work with the natural characteristics of gelatin by utilizing metal vapor deposition, spin coating, and photolithography. Characterization methods have also been optimized through the creation of specialized humidity chambers that isolate specific characteristics such as response time, accuracy, and hysteresis. Collagen-based sensors are found to have a sensitivity to moisture in the range of 0.065 pF/%RH. Diffusion characteristics were also analyzed with the diffusion coefficient found to be 2.5 × 10−5 cm2/s. Absorption and desorption times were .
Convenient Measurements and Speciation of Arsenic in Water by Use of Simple Pretreatments for Atomic Absorption Spectrometry in Combination with Hydride Generation

A combination of three different simple pretreatments is useful and convenient for speciation of As by atomic absorption spectrometry in combination with hydride generation. One of the three pretreatments involves no pre-reduction of As(V) to (III) (PT1). The next one involves pre-reduction by KI (PT2), and the last one involves mineralization of organic As by K_2S_2O_8 and NaOH (PT3) followed by PT2. Micro-wave radiation is effective in PT2 and PT3. The proposed method takes advantage of incomplete but reproducible recovery of As(V) with PT1. The recovery coefficient of As(V) in PT1, κ , is introduced. The value of κ is kept constant during each experimental run under a condition of constant NaBH_4 concentration. The actual amount of each form of As is obtained by solving simultaneous equations which are derived from As amounts detectable after each of the three pretreatments. Analytical results of speciation of As for model sample solutions, containing up to 40 ppb total As, are satisfactory.
Masters Thesis: The impact of event-triggered control on the energy consumption of a legged robot

In event-triggered control (ETC) the control task is only executed when needed to ensure performance or stability. A well known property of ETC is that it can reduce the number of control task executions while retaining similar performance. A large amount of research is focused on how ETC can be used to achieve energy savings in wireless networked control systems. However, the effect of ETC on the actuation energy consumption and whether it could be used as a strategy to achieve actuation energy savings has been unexplored. This thesis presents a study of the impact of ETC on the energy consumption of a legged robot. The focus is on the control task of balancing the robot on top of its legs. To perform this study, a system allowing real-time control and energy monitoring of the robot is developed. This system allowed an experimental comparison between a standard periodic time-triggered controller and a periodic event-triggered controller. Three experiments were performed that enabled time-triggered control and ETC to be compared during transients. The results show that ETC is capable of affecting the energy consumption while reducing the number of control updates. During the first two experiments the system was brought into a transient state by starting the system from nonzero initial conditions. During the third experiment a disturbance was applied on the control input of one leg pair. In the first experiment the energy consumption during ETC increased with 3.0% while in the second and third experiment the energy consumption decreased with 3.2% and 7.8% respectively. These differences occurred while reducing the number of control updates by at least 35.9%. Analysis of the results suggest that the differences in energy consumption are due to the different control input during ETC combined with the effect of unmodeled dynamics. Master of Science Thesis Bastiaan Oosterhuis
Direct Determination of Indium Antimonide Energy Band Parameters from Diamagnetic Exciton Spectra

Diamagnetic exciton spectra of InSb crystals derived from transmission measurements carried out on thin unstressed samples at 1.8 K and in magnetic fields up to 80 kOe are used for a direct determination of parameters of the c- and v-bands. Detailed identification and precise binding energy calculations permit one to derive the cyclotron frequencies of the electron and the holes, and the spin splittings. The m(ϵc) and g(ϵc) relationships thus obtained exhibit good agreement with Kane's model up to energies close to ϵc ϵg. Light holes also reveal a strong nonparabolicity characterized in the linear-in-k4 approximation by the coefficient p1h = 0.47 meV−1. An analysis of the splitting of two light-hole long-wavelength transitions including the diamagnetic exciton binding energies and the data on the c-band obtained permits one to calculate the v-band parameter set. [Russian Text Ignored]
The effect of oxygen remote plasma treatment on ZnO TFTs fabricated by atomic layer deposition

We deposited ZnO thin films by atomic layer deposition (ALD) and then investigated the chemical and electrical characteristics after plasma treatment. The chemical bonding states were examined by X‐ray photoelectron spectroscopy (XPS). The XPS spectra of O 1s showed that the intensity of oxygen deficient regions of the ZnO film decreased from 27.6 to 19.4%, while the intensity of the oxygen bound on the surface of the ZnO film increased from 15.0 to 21.9% as plasma exposure times increased. The ZnO film exhibited a decrease in carrier concentration from 4.9 × 1015 to 1.2 × 1014 cm−3 and an increase in resistivity from 1.2 × 102 to 9.8 × 103 Ω cm as the plasma exposure times increased. To verify the changes in the chemical and electrical properties of the ZnO films caused by the oxygen remote plasma treatment, ZnO thin film transistors were fabricated and their electrical properties were investigated. We found that the Ion/Ioff ratio increased from 7.3 × 104 to 8.6 × 106, the subthreshold swings improved from 1.67 to 0.45 V/decade, and the saturation mobility (µsat) decreased from 1.63 to 0.72 cm2/V s as plasma exposure times were increased.
CdTe‐paper‐based Visual Sensor for Detecting Methyl Viologen

This study developed a method on detecting methyl viologen (paraquat) using a CdTe-paper-based visual sensor. The CdTe Qdots were immobilized on the paper using glycerin. The volume percentages of CdTe in glycerin were optimized to be 50%. The sensing principle is that the methyl viologen quenches the fluorescence intensity of CdTe Qdots in a concentration dependent manner. The sensor is linearly response to the logarithm concentration of the methyl viologen in the range from 0.39 µmol/L to 3.89 mmol/L with a detection limit of 0.16 µmol/L and the correlation coefficient R2 of 0.99. Three parallel experiments at the methyl viologen concentration of 38.89 µmol/L give a relative error of 2.45%, which indicates a good reproducibility. The sensor is not disturbed by other pestisides including omethoate, anilofos, machete and glyphosate isopropylamine salt. The advantages of this sensor are disposable, stable, convenient, and easy to operate.
A Simple and Efficient Highly Enantioselective Synthesis of α-Ionone and α-Damascone

An efficient highly enantioselective (ee ≥99%) synthesis of α-ionone and α-damascone is described. Both enantiomers of title compounds were synthesized through two straightforward pathways diverging from enantiopure (R)- or (S)-α-cyclogeraniol. These versatile building blocks were obtained by regioselective ZrCl4-promoted biomimetic cyclization of (6S)- or (6R)-(Z)-6,7-epoxygeraniol, respectively, followed by deoxygenation of the so formed secondary alcohol. The chiral information was encoded by a highly regioselecive Sharpless asymmetric dihydroxylation of inexpensive geranyl acetate.
Strongly adhesive and flexible transparent silver nanowire conductive films fabricated with a high-intensity pulsed light technique

Large-scale silver nanowire (AgNW) mesh films have received increasing attention as new transparent conductive films used in various printed devices. However, there are two crucial issues in implementing AgNWs that need to be addressed: (1) strong adhesion between AgNW film and substrate and (2) high conductivity with short treatment time for low-cost printed technology. Here, a high-intensity pulsed light (HIPL) sintering technique, which provides extreme heating locally in the AgNW film and at the interface between the film and polymer substrate, sinters the AgNW film to produce high conductivity with strong adhesion on the substrate. Importantly, light intensity, exposure time, and AgNW amount can be adjusted simply to form films that meet specific device needs. A flexible AgNW film with sheet resistance of 19 Ω sq−1 and transmittance of 83% at 550 nm is obtained with only one-step on a polyethylene terephthalate substrate with a light intensity of 1.14 J cm−2 under an exposure time of only 50 μs. The film can endure multiple peeling tests, which will play an important role in printed electronics.