Miracle-dz/UniFAR-FTUs huggingface dataset:
Manufacturing I-123-labelled radiopharmaceuticals. Pitfalls and solutions

A variety of radioiodination methods is described in the radiochemistry literature, however, only a few can fulfil manufacturing requirements. In this article we provide an overview of the process of preparing a radiopharmaceutical to inform the general reader in their everyday use of these products. According to molecular structure of the precursor/ligand, the first decision to be made is whether a nucleophilic or electrophilic approach should be used. Both are suitable for obtaining a high specific activity, as well as for integration in production processes. Feasible reaction conditions and reliability in terms of labelling yield and recovery are further relevant parameters. Recent changes and strengthening of the pharmaceutical regulations mean that I-123 radiopharmaceuticals are often autoclaved. In order to maintain the radiochemical purity during this process, as well as during storage/transport, radical scavengers or antioxidants have to be added. Copyright © 2005 John Wiley & Sons, Ltd.
Challenges of introducing quantitative elementary reactions in multiscale models of thin film deposition

The implementation of detailed surface kinetic mechanisms describing the thin film growth dynamics into models of chemical vapor deposition (CVD) reactors has been a challenge for many years. In this article we review the literature concerning the study of the dynamics of the Si(100)2 × 1 surface and introduce a multiscale model that captures the main features of its reactivity. The model combines the results of ab initio calculations with an atomistic description of the Si surface, obtained using a 3D‐kinetic Monte Carlo (KMC) model that explicitly accounts for the 2 × 1 surface reconstruction and the formation and diffusion of Si dimers on a hydrogenated surface. At the atomistic scale, we determined pre‐exponential factors and activation energies of hydrogen desorption reactions proceeding through the 2H, 3H, and 4H mechanisms. The calculated kinetic constants were embedded in the KMC model and used to simulate literature TPD experimental data. The simulations were used to fit the activation energies of hydrogen desorption reactions, which showed that DFT calculations performed with B3LYP functionals are likely to overestimate hydrogen desorption energies by up to 9 kcal mol−1, which was confirmed by successive ab initio calculations. Two examples of the solution of the KMC model in conjunction with a reactor scale model are provided, in which the coupling was performed adopting both a hierarchic and a two‐way coupling strategy. We found that in the plasma deposition of nanocrystalline silicon performed at low substrate temperatures the growth proceeds through a layer‐by‐layer mechanism on a surface almost completely covered by hydrogen. The application of the same model to the simulation of the thermal CVD of Si showed that at intermediate growth temperatures, when the hydrogen surface concentration is high, a new hydrogen desorption mechanism, in which Si adatoms play an important role, is active.
Linear and nonlinear optical properties of small silicon clusters

Electronic contributions to the optical properties of small silicon clusters are examined. Geometries and the electronic structures of the clusters are established using the tight‐binding model, and linear as well as nonlinear polarizabilities of the clusters are evaluated using one‐electron density matrix techniques. Kleinman’s conjecture for hyperpolarizabilities is shown to be violated in the frequency‐degenerate case, which is of practical importance. The nonlinear polarizabilities are found to depend primarily on the symmetry of the cluster and prove to be high for the low‐symmetry clusters. Possible experiments and applications are discussed.
On the phase transition in a monolayer adsorbed on graphite at temperatures below the 2D-critical temperature

Monte Carlo simulations in the grand ensemble and meso-canonical ensemble in which the adsorbent is connected to a finite reservoir have been used to study adsorption isotherms for monolayer argon adsorption on graphite at temperatures below the 2D-critical temperature in order to elucidate the microscopic details of the 2D-transitions: vapour–solid, vapour–liquid and liquid–solid. An S-shaped van der Waals (vdW) loop was found when a small square surface was used; however, for large square surfaces and rectangular surfaces the isotherms exhibit a vdW-type loop with a vertical segment which indicates the coexistence of two phases separated by a boundary that changes its shape with the loading. This coexistence occurs at the same chemical potential as determined by the mid-density scheme, developed by Do and co-workers (Z. Liu, L. Herrera, V.T. Nguyen, D.D. Do, and D. Nicholson, A Monte Carlo scheme based on mid-density in a hysteresis loop to determine equilibrium phase transition. Mol Simul. 37(11):932–939, 2011; Z. Liu, D.D. Do, and D. Nicholson, A thermodynamic study of the mid-density scheme to determine the equilibrium phase transition in cylindrical pores. Mol Simul. 38(3):189–199, 2011).
Role of Microstructural Properties in the Time-Dependent Sorption/Desorption Behavior of 1,2-Dichloroethane on Humic Substances

This represents the second phase in our efforts to develop a molecular level understanding of sorption/desorption processes at soil surfaces contributing to prolonged retention of nonpolar organic chemicals. Applying techniques developed with clay minerals, the processes are followed in situ from both kinetic and mechanistic perspectives using controlled environment diffuse reflectance infrared spectroscopy in conjunction with chemicals that exhibit isomerization properties. The rapid accumulation and ease of desorption of the first sorbed species detected as vapor phase chemical flows through humic sorbents is consistent with macroscopic partitioning behavior: its conformer populations are in accord with the nonpolar nature of humic substances. A band for a second species, detected only after several hours of sorption, increases in intensity during the sorption phase of the experiment and continues to increase even after days of desorption. Both of these species appear to be in the vapor state, consiste.
An orthorhombic polymorph of melaminium chloride hemihydrate

Crystals of an ortho­rhom­bic polymorph of 2,4,6-triamino-1,3,5-triazin-1-ium chloride hemihydrate, C3H7N6+·Cl−·0.5H2O, were obtained by cocrystallization experiments under aqueous acidic conditions (HCl, pH = 2). In the crystal structure, the melaminium ions, chloride anions and water mol­ecules are linked via hydrogen bonds. All H atoms of the melaminium cation are involved in hydrogen bonds. The chloride anions and the water mol­ecules lie on mirror planes. In the c direction, the melaminium ions are stacked by π–π inter­actions.
Sequence reconstruction in nanopore sequencing

This master thesis is about nanopore sequencing. In this method, a singlestranded DNA oligomer is pulled through a tiny pore. Electric current ows through the pore and is modulated to di erent degrees by the di erent bases contained therein. By measuring the current one can draw conclusions on the DNA sequence. This process is called basecalling. The goal of this thesis is to develop, implement and evaluate algorithms for basecalling. Currently this value is about 80% for a single read. By sequencing the same section multiple times an accuracy of over 99% can be reached. In order to develop a basecaller bidirectional recurrent neural networks are used in this thesis. In addition to their implementation, the optimal hyperparameters, e.g. the size and number of layers, the optimizer, the loss function, etc. are determined. To train the RNN a training dataset must be created rst. For each read, the corresponding section in the reference sequence must be determined in order to assign the actual bases to the read. Since the bases translate the pore at di erent speeds, it is necessary to rst determine from the raw data when a base reaches the pore. Therefore a break point detection is applied. This method detects when the current changes signi cantly. The method used for this work is a window-based break point detection algorithm, which is characterized by its high speed. The evaluations of the test data obtained have shown that the precision of the developed basecaller does not exceed the precision of the basecaller Metrichor, supplied by Oxford Nanopore. An improvement could be achieved by using a di erent break point detection algorithm.
Humic acid removal by electrocoagulation using aluminium sacrificial anode under influencing operational parameters

AbstractHumic acids (HA) in water can react with active chlorine to produce carcinogenic compounds and their presence is, therefore, considered as a serious problem in water purification plants throughout the world. The present study was undertaken with the aim of investigating the efficiency of using an electrocoagulation (EC) process based on aluminium electrodes at a laboratory scale as a complementary treatment step for HA removal from surface water. A series of experimental assays were performed to determine the optimal operating conditions (electrolysis time, pH, current intensity and initial concentration) involved in the EC mechanism during the HA removal process. The findings revealed that under optimum conditions HA could be removed by up to 72%. Further, high performance liquid chromatography and Fourier transform infrared spectroscopy analyses showed the non-forming products and non-attack points of the HA molecules, respectively. Overall, the results yielded in a pH range (6–7) and low curren.
Effect of using a piston with a thermal barrier layer in a spark ignition engine

AbstractIn this study, in order to decrease cold start HC emission at idle and the wide open throttle (WOT) conditions, a thermal barrier layer (TBL) was deposited on the top surface of a piston. The engine was tested at three compression ratios of 8˙2, 7˙2 and 6˙2 and for two different conditions for each compression ratio. At the first stage, cold start HC emission was measured for the first 180 s. Second, the performance and exhaust characteristics were measured at WOT. Cold start HC emission in the engine with TBL decreased compared to the standard engine at the compression ratios tested. While observing an increase in brake power up to 3 and 5% at the compression ratio of 7˙2 and 6˙2 respectively, the brake power decreased up to 6% at the compression ratio of 8˙2 compared to that of the standard engine. Maximum decreases in HC emissions of the engine with TBL piston at WOT were found to be 43˙18, 47˙05 and 32˙12% at the compression ratios of 8˙2, 7˙2 and 6˙2 respectively.
Electroanalytical Methods for the Determination of Pharmaceuticals: A Review of Recent Trends and Developments

Electroanalysis is a powerful analytical technique that is increasing in utility in the pharmaceutical industry. It is used as an alternative or complementary technique to spectrophotometric and separation techniques due to its high sensitivity, speed of analysis, reduction in solvent and sample consumption, and low operating cost compared to other analytical methods. A review of the principles and application of modern electroanalytical techniques, namely, cyclic, linear sweep, differential pulse, square wave and stripping voltammetric techniques, is presented. This review gives recent pharmaceutical analysis applications used for each mode of electroanalytical chemistry. The review will also describe recent developments for enhancing concentration limits of detection, electrode types, and so forth. Selected studies on these subjects are given as examples.
New Sesquiterpenes from Edible Fungus Clavicorona pyxidata

Three new sesquiterpenes, pyxidatol A–C (1–3, resp.), were obtained from the fermentation culture of Clavaria pyxidata, together with two known ones, tsugicoline E (4) and omphadiol (5). Their structures were elucidated through spectroscopic analyses, including 1D- and 2D-NMR experiments, HR-ESI-Q-TOF mass spectrometry, chemical correlation, and X-ray single-crystal diffraction.
EFFECT OF HEATING RATE OF BIOMASS FEEDSTOCK ON CARBON GASIFICATION EFFICIENCY IN SUPERCRITICAL WATER GASIFICATION

ABSTRACT The effect of feedstock heating rate on the efficiency of gasification of a biomass in supercritical water was investigated using a continuous bench-scale reactor. A glucose solution (biomass model compound) and a cabbage slurry were gasified in supercritical water at various heating rates in a preheater. The results show that in the range of 10–30 K/s, carbon gasification efficiency improved as the heating rate increased.
Rapid incorporation of carbon from fresh residues into newly formed stable microaggregates within earthworm casts

Earthworms play an important role in protecting carbon in the soil, but the exact influence of their activity on the distribution and protection of C is still poorly understood. We investigated the effect of earthworms on the formation of stable microaggregates inside newly formed macroaggregates and the distribution of C in them. We crushed (< 250 µm) soil, and subjected it to three treatments: (i) soil + 13C‐labelled residue + earthworms (these added after 8 days' incubation), (ii) soil + 13C‐labelled residue, and (iii) control (no additions), and then incubated it for 20 days. At the end, we measured the aggregate size distribution, total C and 13C, and we isolated microaggregates (53–250 µm) from macroaggregates (> 250 µm) formed. The 13C in fine particulate organic matter between and within the microaggregates was determined. Earthworms helped to form large macroaggregates (> 2000 µm). These large macroaggregates contained four times more stable microaggregates than those from samples without earthworms. There was more particulate organic matter within and between microaggregates in macroaggregates in the presence of earthworms. The larger amounts of organic matter inside stable microaggregates in casts than in bulk soil after 12 days of incubation (140 mg 13C kg−1 soil compared with 20 mg 13C kg−1 soil) indicates that these microaggregates are formed rapidly around freshly incorporated residues within casts. In conclusion, earthworms have a direct impact on the formation of stable microaggregates and the incorporation of organic matter inside these microaggregates, and it seems likely that their activity is of great significance for the long‐term stabilization of organic matter in soils.
Raman shift of stressed diamond anvils: Pressure calibration and culet geometry dependence

The pressure dependence of the Raman shift of diamond for highly stressed anvils at the diamond anvil sample interface has been measured for different culet shapes up to 180 GPa at ambient temperature. By using hydrogen samples, which constitute both a quasihydrostatic medium and a sensitive pressure sensor, some of the effects of culet and tip size have been determined. We propose that the divergent results in the literature can be partly ascribed to different anvil geometries. Experiments show increasing second order dependence of the diamond Raman shift with pressure for decreasing tip size. This is an important consideration when using the diamond anvils as a pressure sensor.
Isothermal crystallization kinetics and mechanical properties of polycaprolactone composites with zinc oxide, oleic acid, and glycerol monooleate

The isothermal crystallization and mechanical behavior of polycaprolactone (PCL) with zinc oxide (ZnO) with oleic acid and glycerol monooleate (GMO) were studied. Theoretical melting points calculated by the Flory–Huggins and Thompson–Gibbs models were thoroughly compared with differential scanning calorimetry experimental observations. The isothermal crystallization kinetic parameters by Avrami analysis showed that crystallization was controlled by nucleation, crystal growth was spherical, and the nucleation type changed between thermal and athermal nucleation. X-ray diffraction showed that when the additives were used together both the crystal thickness and the degree of crystallinity increased. A multiple-response regression analysis was made with the ZnO, oleic acid, and GMO concentrations as variables and the crystallinity as output. Interaction parameters by the Pukanzky model were calculated from the tensile strength at the yield point and indicated that the addition of oleic acid or GMO improved the interface between the ZnO particles and PCL. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1259-1275, 2013
Palladium N-Heterocyclic Carbene Catalysts for the Ultrasound-Promoted Suzuki–Miyaura Reaction in Glycerol

Novel palladium N-heterocyclic-carbene (NHC)-based complexes with 3,4,5-trimethoxybenzyl, alkyl and sulfonate N-substituents were obtained and fully characterized. The new complexes were used as pre-catalysts in the Suzuki–Miyaura coupling of various aryl halides/boron sources in glycerol under pulsed-ultrasound (P-US) activation. High yields were obtained under mild reaction conditions, without formation of undesired by-products. The pure final cross-coupling products were easily recovered without column chromatography and the catalytic/solvent system could be recycled. TEM (transmission electron microscopy) and XPS (X-ray photoelectron spectroscopy) were used to characterize the nanoparticles and to investigate the fate of the catalysts.
Volatile bases and sensory quality-factors in iced white fish

Three catches of cod stored in ice for various periods under identical conditions have been examined in some detail, to ascertain the precision with which changes in the trimethylamine and total volatile-base content and in the sensorily perceptible quality-factors of the fish might be observed, and also the consistency with which such changes are interrelated. The spoilage rates of the sensory variables and the logarithmic spoilage rates of the chemical variables are approximately linear, but differ in the three catches. The uncontrolled scatter of the readings is small. Certain relationships between the variables are consistent in the three catches. For example, that for the odour and flavour scores of the cooked fish holds within the limits of their errors of measurement, and both variables are related to the total volatile bases (T.V.B.) content by relations such as: Flavour + 6.2 log(1 + T.V.B.) = 15.0.
Detecting voice disguise from speech variability: Analysis of three glottal and vocal tract measures

The deliberate attempt by speakers to conceal their identity (voice disguise) presents a challenge for forensics and for automated speaker identification systems. Using a database of natural and disguised voices of three professional voice artists, we build on earlier findings in [Amin et al., 2014] by exploring how certain glottal and vocal tract measures, such as glottal timing (Open Quotient) and vowel formants are manipulated by the artists to create novel voice identities. We also investigate whether there are any features from these measures that can be useful for discriminating natural and disguised voices. As expected, variation in Open Quotient was speaker-dependent, and corresponded closely to social attributes (i.e., age) of the voice identities involved. By modelling the overall variability of speakers in the vowel space, we propose a new method for automatically classifying natural and disguised voices. The proposed method is found to outperform several state-of-the-art methods.
The use of chemical shifts of hydroxy protons of oligosaccharides as conformational probes for NMR studies in aqueous solution. Evidence for persistent hydrogen bond interaction in branched trisaccharides

The 1H NMR chemical shifts, vicinal coupling constants, temperature coefficients, exchange rates with solvent and NOEs have been measured for the hydroxy protons of a series of 15 branched trisaccharides in aqueous solution. These compounds are methyl α-D-galactopyranosides substituted at the 3- and 4-positions with either L-fucosyl or D-glucosyl groups. While most of the hydroxy protons in the trisaccharides have chemical shifts similar to those in the corresponding methyl monosaccharides (Δδ ≤ ±0.20 ppm), some hydroxy protons are found to exhibit large upfield shifts. The NMR data together with HSEA and MM2 calculations show a correlation between these large upfield shifts and the proximity of the hydroxy group to oxygen atoms. The largest upfield shifts are observed for hydroxy protons which are in close proximity to ring oxygens O(5). This dependency of chemical shifts of hydroxy protons on the electronic environment might be used as a conformational probe to improve the determination of conformation of oligosaccharides. The NMR data also show that in three branched trisaccharides, α-D-Glcp-(1→3)-[α-D-Glcp-(1→4)]-α-D-Galp-OMe, β-L-Fucp-(1→3)-[α-D-Glcp-(1→4)]-α-D-Galp-OMe and α-D-Glcp-(1→3)-[β-L-Fucp-(1→4)]-α-D-Galp-OMe, there is a persistent hydrogen bond interaction between the O(2′)H of the 3-linked sugar residue and the O(5″) of the 4-linked sugar residue. In the three compounds, a large upfield shift relative to the constituent methyl monosaccharide is observed for the hydroxy proton O(2′)H involved in hydrogen bonding with the O(5″) oxygen. Additional information about the conformation could also be obtained from the inter-residue NOEs involving the exchangeable hydroxy protons. These additional NOEs are in good agreement with a conformation in which the O(2′)H proton and the O(5″) oxygen atoms are involved in a hydrogen bond interaction.
Molecular dynamics studies on zeolites. Part 5.—Discussion of the structural changes of silicalite

Molecular dynamics simulations of silicalite, with and without sorbed methane molecules, at different temperatures, have been performed using a simple model potential. The results for sorption energetics and diffusion of methane were satisfactory, but the structural properties of the silicalite framework and their dependence on temperature and sorbate loading were reproduced only qualitatively. Suggestions for improvement of model potentials for zeolites are presented.
Natural Fiber Welding

Natural fiber welding is a process by which individual fibers are swollen by an appropriate ionic liquid-based solvent system to form a congealed network. Manipulated fibrous materials may be either composed of natural polymers such as cellulose, hemicellulose, silk, et cetera, or synthetic polymers, or mixed materials. The process is principally controlled by the composition of the solvent system which includes an ionic liquid solvent plus additives such as water, methanol, et cetera. Other conditions such as the amount and placement of solvent, as well as time, temperature, and pressure control the extent to which neighboring fibers are fused. Only the material at the outer surface of fibers need be sufficiently mobile to merge with that of neighboring fibers. Material in the fiber core may be left in the native state by controlling process variables. Fibers form a congealed network upon removal of the ionic liquid-based solvent.
The structure of molten alkali carbonates studied by neutron diffraction and ab initio calculations

The total structure factors, S(Q), of pure molten and an equimolar mixture with , , were measured by neutron diffraction at 1013 K and 923 K, respectively. The results are generally consistent with the findings of previous MD simulations. The ion remains essentially unperturbed in the mixture. The real-space pair correlation functions are consistent with a close-packed, regular, planar, trigonal geometry for the ion in both and . There is some indication, also consistent with the findings of MD simulation, of a possible tightening of the local coordination of ions around in the presence of the larger, more weakly polarizing cation. Modelling the S(Q) data using structure factors calculated from monomer and dimer structures derived from ab initio quantum chemical calculations suggests that larger clusters are needed to realistically describe the melt local structure.