Miracle-dz/UniFAR-FTUs huggingface dataset:
Spherical Nanocrystalline Barium Zirconate Titanate Prepared by Co-Precipitation in Highly Basic Aqueous Solution

Spherical monosized barium zirconate titanate nanoparticles (Ba(ZrxTi1−x)O3 (BZT) when x = 0.25, 0.30 and 0.35) have been prepared by co-precipitation in a strongly alkaline solution (20 M NaOH) at 80°C. The phase formation of the as-precipitated powders was characterized by XRD, FT-IR and Raman spectroscopy as a single-phase BZT with cubic perovskite oxide structure. This indicates that crystalline BZT powders can be obtained from the co-precipitation in 20 M NaOH without the requirement of calcination process. SEM analysis showed that BZT had nanosized spherical morphology with uniform shape and size. The crystal sizes obtained by TEM analysis were 20-40 nm.
Sub-millimetre wave absorption spectra of artificial RNA molecules

We demonstrate submillimetre-wave Fourier transform spectroscopy as a novel technique for biological molecule characterization. Transmission measurements are reported at frequencies 10–25 cm−1 for single- and double-stranded RNA molecules of known base-pair sequences: homopolymers poly[A], poly[U], poly[C] and poly[G], and double-stranded homopolymers poly[A]–poly[U] and poly[C]–poly[G]. Multiple resonances are observed (i.e. in the microwave through terahertz frequency regime). We also present a computational method to predict the low-frequency absorption spectra of short artificial DNA and RNA. Theoretical conformational analysis of molecules was utilized to derive the low-frequency vibrational modes. Oscillator strengths were calculated for all the vibrational modes in order to evaluate their weight in the absorption spectrum of a molecule. Normal modes and absorption spectra of the double-stranded RNA chain poly[C]–poly[G] were calculated. The absorption spectra extracted from the experiment were directly compared with the results of computer modelling thereby, confirming the fact that observed spectral features result from electromagnetic wave interactions with the DNA and RNA macromolecules. Correlation between experimental spectrum and modelling results demonstrates the ability of normal mode analysis to reproduce RNA vibrational spectra.
Reinvestigation of the charge density distribution in arc discharge fusion system

A continual arc discharge system has been setup and the light intensity of arc discharge has been profiled. The mathematical model of local energy density distribution in arc discharge fusion has been simulated which is in good qualitative agreement with light intensity profile of arc discharge in the experiments. Eventually, the local energy density distribution of arc discharge system is able to be precisely manipulated to act as heat source in the fabrication of fused fiber devices.
The First-Day Quiz as a Teaching Technique

The problem with chemical education today is not merely that the students are inattentive, that our instructors are incompetent, or that the subject is intrinsically difficult. I believe the problem is that the fundamentals of the subject are not imparted. As students emerge from the basic courses in chemistry, despite exposure to a range of specific topics, they are commonly unclear on the basic ideas and how they might apply to more advanced topics. In this contribution, I describe a first-day quiz for students in an advanced chemistry class, presented to them ostensibly as a test of basic knowledge. While this approach is not unprecedented, it is apparently rare, as it comes as a surprise to those colleagues I have discussed it with. The important objective of the exercise is to allow students to realize what they don't know about fundamental chemistry, which I have found makes them more receptive to chemical education.
Surface-modified cobalt-based sensor as a phosphate-sensitive electrode

A new phosphate ion-sensitive electrode based on a cobalt matrix has been prepared. The electrode showed a relatively selective potentiometric response toward H 2 PO 4 - which seems to originate from the CoO layer covering the electrode surface. The response mechanism of the electrode is discussed in terms of the host-guest chemistry of a nonstoichiometric compound of CoO
Effects of salts on the micellization and gelation of a triblock copolymer studied by rheology and light scattering

The phase behavior and aggregation properties of a triblock copolymer of ethylene oxide (EO) and propylene oxide (PO), with a measured composition (EO)29(PO)40(EO)29, in aqueous solutions containing salt, have been examined using dynamic light scattering, rheological techniques, and sedimentation and viscosity measurements. The copolymer is dissolved as a unimer at low temperatures and forms spherical micelles with increasing temperature. At higher temperatures, a sphere-to-rod transition is seen for the micelles. Two types of gel are formed at higher concentrations of the copolymer. With different inorganic salts, the micellization and gelation properties of the copolymer follow the same type of transitions as the salt-free system, but all transition temperatures are shifted. The spherical micelles thus transform into rod-like micelles at around 38 °C in 1 M KF, which is approximately 36 deg below the transition temperature in the salt-free system. Rod lengths in 1 M KF are between 1000 and 1800 A, at 40 °C. The higher-temperature gel phase is seen at all concentrations down to 0.5 −1 wt %. The elasticity of this gel is due to hindered rotation of rods. Its relaxation time decreases with increasing concentration, indicating that the gel relaxes due to a partial breakdown or dissolution of the rods at the cross points. The strain dependence of this gel suggests that ordered structures of rods are formed at concentrations above 27 wt %. (Less)
Planet forming disks, debris disks and the Solar System

Abstract VLT instruments and ALMA with their high spatial resolution have revolutionized in the past five years our view and understanding of how disks turn into planetary systems. This talk will briefly outline our current understanding of the physical processes occurring and chemical composition evolving as these disks turn into debris disks and eventually planetary systems like our own solar system. I will especially focus on the synergy between disk structure/evolution modeling and astrochemical laboratory/theoretical work to highlight the most recent advances, and open questions such as (1) how much of the chemical composition in disks is inherited from molecular clouds, (2) the relevance of snowlines for planet formation, and (3) what is the origin of the gas in debris disks and what can we learn from it. For each of the three, I will outline briefly how the combination of theory/lab astrochemistry, astrophysical models and observations are required to advance our understanding.
Variation of Chemical and Morphological Characters of Leaves and Unripe Cones in Juniperus Communis

Abstract The variation of content of essential oil and pinene isomers and morphological parameters of leaves and unripe cones in Juniperus communis L. was studied. Leaves and cones were collected separate from 110 J. communis individuals in 11 different habitats throughout Lithuania. Essential oils were analysed by capillary gas chromatography (GC). The study showed more intensive essential oil accumulation and higher intraspecific variation of essential oil amount in unripe cones than in leaves. Significant differences between α- and β- pinene amounts were observed in J. communis. β-Pinene was detected in much higher quantities than α-pinene. Positive correlation was detected between pinene isomers in cones and leaves (r = 0.44, p < 0.05 and r = 0.50, p < 0.05, respectively) of the same tree showing pinene isomers common biosynthetic pathway. Significant differences between populations were characteristic of J. communis according to leaf length, unripe cones mass and essential oil yield in leaves, however, significant correlation was established between essential oil yield of leaves and habitat illumination (r = -0.67, p < 0.05) and soil acidity (r = -0.80, p < 0.05) only. Santrauka Buvo tirtas paprastojo kadagio (Juniperus communis) lapų bei neprinokusių kankorėžėlių cheminių ir morfologinių parametrų įvairavimas tarppopuliaciniame ir individų lygiuose. Lapai ir kankorėžėliai buvo surinkti atskirai nuo 110 individų iš dešimties ekologiškai skirtingų augaviečių Lietuvoje. Eterinių aliejų analizė atlikta dujų chromatografijos metodu. Tyrimai parodė, kad eterinio aliejaus daugiau susikaupia ir jų kiekis labiau įvairuoja neprinokusiuose kankorėžėliuose nei lapuose. Nustatyti dideli pineno izomerų kiekio skirtumai: lapuose ir kankorėžėliuose β-pineno buvo atitinkamai 26 ir 32 kartus mažiau nei α-pineno. Nustatyti teigiami koreliaciniai ryšiai tarp pineno izomerų kiekio kankorėžėliuose (r = 0,44, p < 0,05) ir lapuose (r = 0,50, p < 0,05) rodo, kad egzistuoja bendras α- ir β-pineno biosintezės kelias. Nustatyta patikima teigiama koreliacija tarp lapų ilgio ir lapų masės (r = 0,44, p < 0,05). Statistinė analizė parodė, kad J. communis lapų ilgiui, neprinokusių kankorėžėlių masei ir eterinio aliejaus kiekiui lapuose yra būdingi patikimai dideli tarppopuliaciniai skirtumai. Tačiau statistiškai patikimi koreliaciniai ryšiai nustatyti tik tarp eterinio aliejaus kiekio lapuose ir augavietės apšviestumo (r = -0,67, p < 0,05) bei dirvožemio rūgštingumo (r = -0,80, p < 0,05).
Stabilization of Minerals by Reaction with Phosphoric Acid: Evolution of Model Compounds

The mechanisms of heavy metal stabilization from mineral residues were investigated. The reaction of phosphoric acid with municipal waste incinerator fly ashes and some of its major constituents was assessed. The reaction was monitored by analysis of soluble phosphate contents as a function of time, as well as by pH and temperature variations. Evolution of the solids was followed by X-ray diffraction. Various phosphoric acid concentrations were used and yielded different end products for the case of lime and limestone. Silica and calcium sulphate were found to remain inert, while alumina consumed part of the soluble phosphate. Melilite showed a complex process of dissolution and precipitation of amorphous aluminium phosphates. These results help on understanding the phosphate reaction used to stabilize a mineral matrix like fly ash and demonstrate that insoluble minerals are formed such as calcium phosphates which may effectively trap heavy metal ions.
Hierarchical Structures of Silicon Oxynitride Nanowires Formed by a Gallium-Catalyzed In Situ Reactive Technique

Novel doughnut-like loop structures of silicon oxynitride were grown over a Si substrate via self-assembly of ordered nanowires. These hierarchical structures were formed by metallic gallium-catalyzed vapor-liquid-solid growth at high temperature under a flow of NH3 gas. The product was characterized by XRD, SEM, EDS mapping and XPS techniques. XRD characterization confirms the formation of Si3N4 and silicon oxynitride phases. The silicon oxynitride loop structures assembled by ordered nanowires have outer diameters of 10-14 mm and wall thickness of 2-3 mm. The nanowire bundles in a single loop exhibit a petal-like growth mode. EDS mapping verifies the elemental distribution over the structure. XPS analyses disclose the binding contribution from Si3N4, silicon oxynitride and silicon oxide. The formation mechanism of the self-assembled structures was analyzed based on the growth process.
Light Scattering from Wormlike Micelles in an Elongational Field

The radii of gyration of wormlike “living polymer” micelles of tetradecyltrimethylammonium bromide/salicylate have been measured in an elongational field at various elongation rates. The radius of gyration in the flow direction first increases, indicating alignment with the field, reaching a maximum at a critical elongation rate before falling. This decrease is taken as evidence for micelle scission at high velocity gradients. The microscopic structural measurements are consistent with inferences drawn from rheological measurements on similar systems.
The low-temperature specific heat of FeS and M0.875X (M = Fe, Co; X = S, Se) with a NiAs-like structure

We have measured the specific heat of FeS, Fe0.875X, and Co0.875X (X = S,Se) compounds with a NiAs-like structure over the temperature range from 2 to 30 K. It was found that the ground state of FeS has an insulating character. The opening up of a gap in the density of states is probably caused by electron correlation. Two types of superstructure are known to occur due to ordering of vacancies at iron sites in Fe0.875X; one is a 3c structure and the other a 4c structure. The -values obtained for 3c structure are about 10% larger than those of 4c structures. Accordingly, this result indicates that the electronic structure of Fe0.875X should be sensitive to the ordered structure of the vacancies. Since the -values obtained for non-stoichiometric compounds are larger than the calculated ones, there is electron effective-mass enhancement in non-stoichiometric compounds. Moreover comparison of the observed and calculated electronic contributions to the low-temperature specific heat suggests that the mass enhancement in Pauli-paramagnetic Co0.875X is larger than that in ferrimagnetic Fe0.875X.
On the Mechanism of Membrane Protein Crystallization in Lipidic Mesophases

The in meso method for crystallizing membrane proteins has been shown to work with a range of different protein types. The method involves reconstituting the target protein into the bilayer of a bicontinuous lipid mesophase followed by an induced phase separation brought on by the addition of a precipitant. A mechanism has been proposed for how in meso crystallogenesis comes about at a molecular level. However, aspects of the hypothesis are not fully developed. These are examined and expanded on here by considering the behavior of related but simpler systems and processes where the mode of action is understood and founded in experiment. By building up from this series of model, well behaved systems a more complete view of what takes place during the in meso crystallogenesis of membrane proteins is obtained. In addition to the underlying theory, some of the more practical aspects of the method are explored and their basis in the hypothesis is established. This treatment suggests a host of experiments to fu.
Theoretical study of conformational features of NAD+ and NADH analogs: protonated nicotinamide and 1,4-dihydronicotinamide

The conformations of nicotinamide (N + ) and 1,4-dihydronicotinamide (NH) have been studied by ab initio calculations at the MP2/6-31G * //6-31G * level. The amide group favors a cis conformation by about 1 kcal/mol for both N + and NH. The rotational barrier for cis to trans interconversion is about 4 and 7 kcal/mol for N + and NH, respectively. The amide group in the trans conformation is out of plane by about 20 o . The 1,4-dihydronicotinamide ring is slightly puckered and adopts a boat conformation. The calculated 15 N equilibrium isotope effect for hydride transfer is small, in agreement with experimental observations
Exporting lignin or power from heat-integrated kraft pulp mills: A techno-economic comparison using model mills

Lignin separation and increased power generation are two alternatives for utilising a steam surplus at a kraft pulp mill. Lignin can be separated from the black liquor by using CO2 in a precipitation process. The resulting lignin can be sold as a biofuel. In this study, lignin separation and increased power generation have been compared by using computer models representing typical Scandinavian mills (327,000 ADt/a). In the studied mills, the steam surplus was up to 437 GWh/a (4.82 GJ/ADt) which enabled either increased power generation by 126 GWh/a(+65%) or extraction of 500 GWh/a lignin. A consequence of extracting this amount of lignin was that the power generation decreased by 59 GWh/a (-30%), which means that the profitability of lignin separation was dependent on the electricity price. Moreover, the profitability was mainly dependent on the lignin price and the cost for CO2 to precipitate the lignin. For lignin separation to give the same annual earnings as increased power generation, the ratio between the electricity price and lignin price had to be 1.9-2.3. For ratios below 1.9, lignin separation was economically preferable, while ratios above 2.3 meant that increased power generation was preferable. It was noticeable that the profitability under all studied conditions was considerably lower for lignin separation than for power generation at high electricity prices. Lignin prices around 15 €/MWh implied that the electricity price had to be below 33 €/MWh for lignin separation to give higher annual earnings than increased power generation. For a high electricity price (55 €/MWh, e.g. including policy instruments), the lignin price had to be above 23.8 €/MWh for lignin separation to give higher annual earnings. These lignin prices are significantly higher than equivalent biofuel prices today. However, the lignin price would probably be higher than 25 €/MWh if lignin were used e.g. as raw material for specialty chemicals or as a replacement for fossil fuels.
Dynamic mechanical analysis of urea–formaldehyde resin adhesives with different formaldehyde‐to‐urea molar ratios

As a part of abating formaldehyde emissions of urea–formaldehyde (UF) resin adhesives, using dynamic mechanical analysis (DMA), we attempted to investigate the influence of the formaldehyde to urea (F/U) molar ratio on the thermomechanical curing of UF resin adhesives with different F/U molar ratios. The thermomechanical curing of these UF resin adhesives was characterized with DMA parameters such as the gel temperature, maximum storage modulus, peak temperatures of the storage and loss moduli, and maximum tan δ. As the F/U molar ratio decreased, the gel temperature of UF resin adhesives increased, whereas the maximum storage modulus, an indicator of the rigidity of UF resin adhesives, decreased. The maximum tan δ increased with the F/U molar ratio decreasing, and this indicated that the UF resin adhesive with a low F/U molar ratio had greater damping than the one with a high F/U molar ratio. A decrease in the rigidity of the UF resin with a lower F/U molar ratio was explained by the calculated crosslinking density, which decreased with the F/U molar ratio decreasing. These results partially explained why UF resin adhesives with lower F/U molar ratios showed relatively poor adhesion performance when they were applied to the manufacture of wood panels. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Neopterin, β2-Microglobulin, Tryptophan and Kynurenine In Sporadic Amyotrophic Lateral Sclerosis

Summary In 62 patients diagnosed as sporadic amyotrophic lateral sclerosis (sALS), we quantitated serum concentrations of neopterin, β2-microglobulin. kynurenine and tryptophan. A linear increase with age was demonstrated by neopterin more than by β2-microglobulin, whereas neither parameter corresponded to individual progression or duration of disease at the time of examination. All serum (n = 79) and cerebrospinal fluid (CSF, n = 11 patients) concentrations remained within reference limits, and serum neopterin always exceeded CSF neopterin. Serum neopterin was not elevated in sALS. and we observed no correlation between circulating IgG isotype concentrations and serum neopterin. Total duration of sALS. as measured in months from the first clinical signs or symptoms to death, seemed. however. to inversely correlate with the mean patient serum neopterin before and after correction for age, and in the absence of any neoplastic process. If confirmed in a larger number of sALS patients, this would parallel a reportedly negative association of CSF neopterin and survival in human immunodeficiency virus (HIV1) infection.
Comparison of 2H and 13C NMR Relaxation Techniques for the Study of Protein Methyl Group Dynamics in Solution

A comparison of 2H- and 13C-based NMR relaxation methods to characterize the dynamics of methyl groups in proteins is presented. Using human ubiquitin as a model system, the field dependence of carbon and deuterium relaxation parameters has been measured and used to probe the utility of various forms of the model-free formalism in revealing the underlying dynamics. We find that both approaches reveal the same overall dynamical features provided that suitable parametrization and model-free spectral densities are employed. It is found that the original and extended model-free formalisms yield different descriptions of the methyl group dynamics and that the extended version is more appropriate for the analysis of carbon relaxation. Because of the inherent differences in the types of information that 2H and 13C offer, deuterium methods appear to provide robust access to methyl symmetry axis order with the least amount of data, while carbon methods provide more robust access to model-free parameters defining t.
Patterns of land use, zoning and economies of scale in cities: three essays on urban economics for Brazil

This thesis is divided into three empirical essays in the field of urban economics, analyzing the case of Brazilian cities. The first essay uses a novelty microdata of 98,198 individual parcels in the city of Recife to investigate the determinants of the urban land use. Through a semi-parametric spatial econometric approach, it is observed that there are considerable local spatial effects. In addition, we note some regularities in the spatial distribution of urban land use. Transport infrastructures tend to attract the development of commercial activities, while natural amenities encourage residential land use. The objective of the second essay is to evaluating the impact of zoning ordinances on the housing market. Using matching methods and a dataset covering all Brazilian municipalities, we evidenced that zoning generates an increment ranging from 5.4% to 6.3% on the average rents, but do not affect the house growth. In addition, we conducted sensitivity analyses that suggests that this result is not simply driven by unobservable confounders. Finally, the third essay investigates the impact of municipal secession on local public expenditures through a Differences-in-Differences approach. The results indicate that those municipalities that experienced a secession process increased their per capita capital expenditures by 14.7%. In addition, we show evidence that suggests that this increase in expenses can be explained by a reduction in economies of scale and rent-seeking behavior.
Two- and three-body interactions in the Θ state: linear and star polymers

The conformation of linear and star polymers is studied at the Θ temperature, determined by the vanishing of the second virial coefficient. This is achieved through exact compensation of intermolecular two-body attractions and three-body repulsions. The analogous compensation within the molecule is not complete, leaving in the star residual three-body repulsions because of a larger multiplicity. The resulting expansion is mostly concentrated in the core region. Its effect on the overall polymer size is discussed in terms of the topological ratio g= star / lin , being the mean-square radius of gyration