Toxic Text in Personas: An Experiment on User Perceptions

When algorithms create personas from social media data, the personas can become noxious via automatically including toxic comments. To investigate how users perceive such personas, we conducted a 2 × 2 user experiment with 496 participants that showed participants toxic and non-toxic versions of data-driven personas. We found that participants gave higher credibility, likability, empathy, similarity, and willingness-to-use scores to non-toxic personas. Also, gender affected toxicity perceptions in that female toxic data-driven personas scored lower in likability, empathy, and similarity than their male counterparts. Female participants gave higher perceptions scores to non-toxic personas and lower scores to toxic personas than male participants. We discuss implications from our research for designing data-driven personas

Supported ionic liquid materials for L-asparaginase bioconjugation

Since the average life expectancy is increasing, several fatal diseases usually related to aging, such as cancer, heart and neurological diseases have become predominant. Biopharmaceuticals, namely nucleic-acid-based products, antibodies, recombinant proteins and enzymes are fundamental to overcome these age-related diseases. Actually, the gold standard enzyme for the treatment of acute chronic lymphoblastic leukemia (ALL) is L-asparaginase (ASNase). Hence, the reusability of this high-priced drug enables the cost reduction of treatments, which allows its routinely use by a widespread population. In this work, functionalized nanomaterials, namely supported ionic liquid materials (SILs) based on silica, formerly described in the literature for the separation of natural compounds from vegetable biomass, were studied as a cost effective support for ASNase immobilization and reuse. Commercial ASNase was used for preliminary tests. Several experimental immobilization conditions, such as pH, contact time, ASNase concentration and SILs recyclability were assessed and optimized, regarding the immobilized ASNase activity, assessed by Nessler reaction, which quantifies the amount of ammonium released after the enzymatic reaction with L-asparagine and immobilization yield. In fact, ASNase immobilization onto the SILs was successfully achieved with an immobilized ASNase activity ranging from 0.6 to 0.9 U of enzyme per mg of SILs under the optimum immobilization conditions. Moreover, all SILs allowed 5 cycles of reaction, while keeping more than 75% of initial ASNase activity. Through the envisioned immobilization strategy, process costs will be considerably reduced, which can lead to a wider use of ASNase in diverse fields of application.publishe

NMR Crystallography: Toward Chemical Shift-Driven Crystal Structure Determination of the β‑Lactam Antibiotic Amoxicillin Trihydrate

We report a new strategy for NMR crystallography of multiple-component molecular crystals in which ¹H NMR chemical shifts enter directly in the structure generation step, governed by a genetic algorithm. Chemical shifts are also used in the structure-refinement step as pseudoforces acting on the models, leading to the lowest-energy structure. This methodology, which avoids the use of time-consuming <i>ab initio</i> chemical shift calculations, is successfully applied to powdered amoxicillin trihydrate, a widely used β-lactamic antibiotic

Classification of Fuel Blends Using Exploratory Analysis with Combined Data from Infrared Spectroscopy and Stable Isotope Analysis

Chemometric tools were applied for exploratory analysis and classification of fuel blends using the combined information on Fourier transform infrared spectroscopy and stable isotope analysis through isotope ratio mass spectrometry. Principal component analysisand hierarchical clustering analysis were applied for exploratory analysis, while support vector machine (SVM) was used to classify the biodiesel/diesel blends. All of the chemometric models used present better results from the combination of spectral information with isotopic data for biodiesel contents of over 10% in the mixture, with the best results being obtained from the SVM classification. Therefore, the development presented in this paper could become an important technique to improve the discrimination of the feedstock used in biodiesel production and a resource for quality control in industry

Classification of Fuel Blends Using Exploratory Analysis with Combined Data from Infrared Spectroscopy and Stable Isotope Analysis

Chemometric tools were applied for exploratory analysis and classification of fuel blends using the combined information on Fourier transform infrared spectroscopy and stable isotope analysis through isotope ratio mass spectrometry. Principal component analysisand hierarchical clustering analysis were applied for exploratory analysis, while support vector machine (SVM) was used to classify the biodiesel/diesel blends. All of the chemometric models used present better results from the combination of spectral information with isotopic data for biodiesel contents of over 10% in the mixture, with the best results being obtained from the SVM classification. Therefore, the development presented in this paper could become an important technique to improve the discrimination of the feedstock used in biodiesel production and a resource for quality control in industry

Cation Symmetry effect on the Volatility of Ionic Liquids

This work reports the first data for the vapor pressures at several temperatures of the ionic liquids, [C_<i>N</i>/2C_<i>N</i>/2im]­[NTf₂] (<i>N</i> = 4, 6, 8, 10, 12) measured using a Knudsen effusion apparatus combined with a quartz crystal microbalance. The morphology and the thermodynamic parameters of vaporization derived from the vapor pressures, are compared with those for the 1-alkyl-3-methylimidazolium bis­(trifluoromethylsulfonyl)­imide series, [C_<i>N</i>–1C₁im]­[NTf₂] (<i>N</i> = 3 – 9, 11, and 13). It was found that the volatility of [C_<i>N</i>/2C_<i>N</i>/2im]­[NTf₂] series is significantly higher than the asymmetric cation ILs with the same total number of carbons in the alkyl side chains, [C_<i>N</i>–1C₁im]­[NTf₂]. The observed higher volatility is related with the lower enthalpy of vaporization. The symmetric cation, [C_<i>N</i>/2C_<i>N</i>/2im]­[NTf₂], presents lower entropies of vaporization compared with the asymmetric [C_<i>N</i>–1C₁im]­[NTf₂], indicating an increase of the absolute liquid entropy in the symmetric cation ILs, being a reflection of a change of the ion dynamics in the IL liquid phase. Moreover both the enthalpy and entropy of vaporization of the [C_<i>N</i>/2C_<i>N</i>/2im]­[NTf₂] ILs, present a clear odd–even effect with higher enthalpies/entropies of vaporization for the odd number of carbons in each alkyl chain ([C₃C₃im]­[NTf₂] and [C₅C₅im]­[NTf₂])

Heterogeneous Catalysts for Olefin Polymerization: Mathematical Model for Catalyst Particle Fragmentation

A model for studying the catalyst fragmentation in the early stages of olefin polymerization is presented. The model is based on measurable and observable parameters of the catalyst and on the energy balance for the fragmentation phenomenon. The model allows the fragmentation behaviors to be discriminated regarding the influence of particle size, polymerization rate, and active site distribution. The results are supported by experimental studies available in the literature indicating the deterministic nature of the model and its capabilities of prediction. The performance of the model allows the optimization of the catalyst synthesis in terms of the nature of the support as well as particle and pore morphology

Combining Multinuclear High-Resolution Solid-State MAS NMR and Computational Methods for Resonance Assignment of Glutathione Tripeptide

We present a complete set of experimental approaches for the NMR assignment of powdered tripeptide glutathione at natural isotopic abundance, based on <i>J</i>-coupling and dipolar NMR techniques combined with ¹H CRAMPS decoupling. To fully assign the spectra, two-dimensional (2D) high-resolution methods, such as ¹H–¹³C INEPT-HSQC/PRESTO heteronuclear correlations (HETCOR), ¹H–¹H double-quantum (DQ), and ¹H–¹⁴N <i>D</i>-HMQC correlation experiments, have been used. To support the interpretation of the experimental data, periodic density functional theory calculations together with the GIPAW approach have been used to calculate the ¹H and ¹³C chemical shifts. It is found that the shifts calculated with two popular plane wave codes (CASTEP and Quantum ESPRESSO) are in excellent agreement with the experimental results

<i>N</i>‑Heterocyclic Carbene Catalyzed Addition of Aldehydes to Diazo Compounds: Stereoselective Synthesis of <i>N</i>‑Acylhydrazones

An innovative stereoselective synthesis of <i>N</i>-acylhydrazones <i>via</i> an unprecedented <i>N</i>-heterocyclic carbene catalyzed addition of aldehydes to diazo compounds is presented. Enals exclusively afforded <i>N</i>-acylhydrazones, in yields up to 91%. The observed regioselectivity was traced back to the reaction of the vinylogous Breslow intermediate <i>via</i> the acyl anion pathway over competing homoenolate, enol, and acyl azolium pathways. This unusual reaction profile was studied based on DFT calculations, which revealed that the reaction is under orbital control, rather than being ruled by charge