The use of molecularly modified Si nanowire field effect transistors (SiNW FETs) for selective detection in the liquid phase has been successfully demonstrated. In contrast, selective detection of chemical species in the gas phase has been rather limited. In this paper, we show that the application of artificial intelligence on deliberately controlled SiNW FET device parameters can provide high selectivity toward specific volatile organic compounds (VOCs). The obtained selectivity allows identifying VOCs in both single-component and multicomponent environments as well as estimating the constituent VOC concentrations. The effect of the structural properties (functional group and/or chain length) of the molecular modifications on the accuracy of VOC detection is presented and discussed. The reported results have the potential to serve as a launching pad for the use of SiNW FET sensors in real-world counteracting conditions and/or applications.

Abstract:Two of the biggest challenges in medicine today are the need to detect diseases in a non-invasive manner, and to differentiate between patients using a single diagnostic tool. The current study targets these two challenges by developing a molecularlymodified Silicon Nanowire Field Effect Transistors (SiNW FETs) and showing its use in the detection and classification of many disease breathprints (lung cancer, gastric cancer, asthma and Chronic Obstructive Pulmonary Disease). The fabricated SiNW FETs are characterized and optimized based on a training set that correlated their sensitivity and selectivity towards volatile organic compounds (VOCs) linked with diseased states. The best sensors obtained in the training set are then examined under real-world clinical conditions, using breath samples from 374 subjects. Analysis of the clinical samples showed that the optimized SiNW FETs can detectand discriminate between almost all binary comparisons of the diseases under examination with >80% accuracy. Overall, this approach has the potential to support detection of many diseases in a direct positive way, which can reassure patients and prevent numerous negative investigations. 3Physicians are always challenged by the need to give the correct diagnosis as early in the onset of a disease is possible, whether the disease-related symptoms are absent or not evident.1 Symptoms are not always characteristic of one particular disease; overlap of symptoms is common in, for example, lung diseases. 2 Patients with different respiratory diseases, such as malignant or benign tumors, or substantially less severe diseases, may have similar symptoms, e.g. cough, chest pain, difficulty to breathe, etc. These symptoms may be characteristic of lung cancer (LC), pneumonia, asthma, and chronic obstructive pulmonary disease (COPD). 1,2Therefore, it is of particular clinical importance to find a diagnostic tool capable of distinguishing between these diseases. A diagnostic tool that involves no needle, surgery and/or active materials and/or radioactive exposure would have a benefit.A highly promising approach that could meet the aforementioned need is based on the detection and classification of the disease breathprint, viz. the chemical profiles of highly-and semi-VOCs in exhaled breath linked with disease. [3][4][5][6][7][8][9][10][11][12][13][14][15] The rationale behind this approach relies on the fact that VOCs generated by cellular metabolic pathways during a specific disease circulate in the blood stream and diffuse into exhaled breath, which is easily sampled. 4,16,17 In certain instances, analysis of breathprints offers several potential advantages, such as: (a) breath samples are non-invasive and easy to obtain; (b) breath contains less complicated mixtures than either serum or urine; and (c) breath testing has the potential for direct and real-time diagnosis and monitoring. 3,18-21Several mass-spectrometry and spectroscopy studies have shown that the breathprint of a specific disease differs from that of healthy control...

The specific density and molar liquid volume of 40 imidazolium-based ionic liquids were predicted using the COSMO-RS method, a thermodynamic model based on quantum chemistry calculations. A molecular model of ion pairs was proposed to simulate the pure ionic liquid compounds. These ion-paired structures were generated at the B3LYP/6-31++G** computational level by combining the cations 1-methyl- (Mmim+), 1-ethyl- (Emim+), 1-butyl- (Bmim+), 1-hexyl- (Hxmim+), and 1-octyl-3-methylimidazolium (Omim+) with the anions chloride (Cl-), tetrafluoroborate (BF4 -), tetrachloroferrate (FeCl4 -), hexafluorophosphate (PF6 -), bis(trifluoromethanesulfonyl)imide (Tf2N-), methylsulfate (MeSO4 -), ethylsulfate (EtSO4 -), and trifluoromethanesulfonate (CF3SO3 -). Satisfactory agreement with the available experimental measurements was obtained, showing the capability of the current computational approach to describe the effect of the anion nature and cation substituent on the volumetric properties of this family of ionic liquids. Thus, calculated and experimental density values of ionic liquids (and also other common solvents) were fitted by linear regressions with correlation coefficients R > 0.99 and standard deviations SD < 20 kg/m3. Consequently, molar liquid volumes were also predicted very accurately by COSMO-RS, indicating the suitability of the ion-pair model to describe intermolecular interactions of pure ionic liquids. In this sense, the σ-profiles of the ion-paired molecules were used to qualitatively analyze the influence of cation and anion natures of ionic liquids on their volumetric properties. As a result of the analysis, we propose the charge distribution area below the σ-profile (S σ -profile) as a simple a priori parameter to characterize the contributions of cation and anion to the ionic liquid behavior as tool to design solvents.

Heat capacity, glass-transition, crystallization, and melting temperatures of 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][EtSO 4 ]) and 1-butyl-3-methylimidazolium methylsulfate ([Bmim][MeSO 4 ]) ionic liquids (ILs) have been determined by differential scanning calorimetry (DSC). Their thermal stabilities have been analyzed by thermogravimetric analysis (TGA). Given the effect of the heating rate over the decomposition temperatures, isothermal TGA experiments are proposed as a more appropriate method to evaluate the thermal stability of the ILs. Inside the working range (-150 °C to 30 °C), [Emim][EtSO 4 ] and [Bmim][MeSO 4 ] present a glass-transition temperature of -78.4 °C and -91.9 °C, respectively. [Bmim][MeSO 4 ] has a melting temperature of -4.1 °C. The C p was determined in a working range (10 °C to 100 °C) where its value increases lineally with temperature.

An ambipolar poly(diketopyrrolopyrrole-terthiophene)-based field-effect transistor (FET) sensitively detects xylene isomers at low ppm levels with multiple sensing features. Combined with pattern-recognition algorithms, a sole ambipolar FET sensor, rather than arrays of sensors, can discriminate highly similar xylene structural isomers from one another.

The good stability and suitable polarity of the 1-alkyl-3-methyl bis(trifluoromethylsulfonyl)imide ionic liquids have prompted their use as solvents for the extraction of mixtures of aromatic and aliphatic hydrocarbons. In this paper, aiming to extend the study of these ionic liquids, the liquid-liquid equilibrium for the systems tolueneThe experiments with [mmim][Tf 2 N] and [emim]Tf 2 N have shown good results in the separation of toluene from heptane compared with the distribution ratio and separation factor of sulfolane in the whole range of composition. The degree of consistency of the experimental LLE data was ascertained by applying the Othmer-Tobias correlation. The phase diagrams for the ternary systems were plotted, and the tie lines correlated with the NRTL model compare satisfactorily with the experimental data.

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The effect of temperature on density, viscosity, and surface tension of 1-butyl-3-methylimidazolium methylsulfate [bmim] [MeSO 4 ] and 1-ethyl-3-methylimidazolium ethylsulfate [emim][EtSO 4 ] ionic liquids (ILs) has been determined. Viscosity values of both ILs above-mentioned have been modeled by the Arrhenius equation and the Vogel-Fulcher-Tammann expression. Density, viscosity, surface tension, and surface excess energy of [bmim][MeSO 4 ] and [emim][EtSO 4 ] decreases as the temperature increases.