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The microwave spectrum of 2,4-dimethylpyrrole was investigated using a Fourier-transform microwave spectrometer in a supersonic expansion. Torsional splittings arising from two inequivalent methyl internal rotors in combination with hyperfine splittings due to the nuclear quadrupole coupling of the 14N nucleus were observed. The experiments were accompanied by quantum chemical calculations. A total of 1561 rotational lines were assigned and fitted in global fits using the programs XIAM and BELGI-Cs-2Tops-hyperfine, both achieved the measurement accuracy of 4 kHz. Local separate fits were also performed to verify the correctness of the assignment. Accurate experimental molecular and internal rotation parameters could be deduced and compared to the calculated ones. The barrier to internal rotation of the 2-methyl rotor was determined to be 277.830(26) cm−1, essentially the same as the value of about 280 cm−1 found for 2-methylpyrrole but lower than the value of 317 cm−1 found for 2,5-dimethylpyrrole. The torsional barrier value of the 4-methyl rotor is 262.210(27) cm−1, slightly higher than the value of 246 cm−1 found for 3-methylpyrrole. Benchmarking the rotational constants for 2,4- and 2,5-dimethylpyrrole revealed that the MP2/6-31G(d,p) level could be helpful to guide the assignment of microwave spectra of pyrrole derivatives. [ABSTRACT FROM AUTHOR]

A number of internal rotation codes can deal with the combination of one or two internal rotors with one 14N quadrupole nucleus, but once it comes to two 14N nuclei, no such code is available even for the case of one internal rotor. We present here the extension of our internal rotor program called BELGI-2N using the rho-axis method global approach to deal with compounds containing one methyl rotor and two weakly coupling 14N nuclei. To test our new code, we applied it to the microwave data recorded for N-methylimidazole, 2-methylimidazole, 4-methylimidazole, and 5-methylimidazole using a chirped-pulse Fourier transform microwave spectrometer in the 7.0–18.5 GHz frequency range. Compared to the previously published study, BELGI-2N was able to (i) significantly increase the number of assigned and fitted lines, (ii) fit the complete datasets considering both the internal rotation and the 14N nuclear quadrupole coupling effects simultaneously, and (iii) achieve standard deviations within the measurement accuracy for all methylimidazole isomers. [ABSTRACT FROM AUTHOR]

This study aimed to explore the spatial interaction between search flow and house price levels. It utilized migration flow data from 2011 and house price data from the same year in Greater Manchester, United Kingdom. The methodology included Chi-square tests and a series of visual maps to explore and visualize the relationship between current areas and search areas. The study examined five house price ranges with matches and mismatches between search patterns and current patterns and tried to illuminate the underlying causes. The research results could prove beneficial for policymakers and planners in discerning distinct migratory patterns and geographical regions, thereby facilitating the formulation of well-informed decisions.

We investigated the rotational spectrum of 2,5-dimethylfluorobenzene containing coupled large amplitude motions of two methyl groups in the frequency range from 2 to 26.5 GHz using a pulsed molecular jet Fourier transform microwave spectrometer. The internal rotation of two inequivalent methyl groups with low torsional barriers (around 16 and 226 cm−1) causes splittings of all rotational transitions into quintets with separations of up to hundreds of MHz between the torsional components. Spectral analysis and modeling of the observed splittings were performed using the programs XIAM and BELGI-Cs-2Tops, whereby the latter achieved measurement accuracy. The methyl internal rotation can be used to examine the electronic and steric environments around the methyl group because they affect the methyl torsional barrier. Electronic properties play a particularly important role in aromatic molecules in the presence of a π-conjugated double bond system. The experimental results were compared with those of quantum chemistry. Benchmark calculations resulted in the conclusion that the B3LYP-D3BJ/6-311++G(d,p) level of theory can be recommended for predicting rotational constants to guide the microwave spectral assignment of dimethylfluorobenzenes in particular and toluene derivatives in general. [ABSTRACT FROM AUTHOR]

Summary In this study, a lactic acid bacteria strain isolated from oats was used as a producer to obtain exopolysaccharide (EPS) using MRS agar plates. The findings indicated that the bacterial strain identified as Weissella cibaria (accession number: PP515290) was shown to have good probiotic activity, adapt better to alkaline than acidic conditions, and efficiently produce EPS at concentrations of up to 7.93 g L−1. SEM images showed a smooth surface and compact particle whereas FTIR confirmed the basic functional groups of polysaccharides in the sample. Meanwhile, XRD analysis demonstrated a non‐crystalline amorphous structure and thermal analysis indicated two‐phase thermal decomposition with maximum rate at 210 °C. Subsequently, EPS from W. cibaria was applied as stabiliser in set‐type yogurt (ex situ) in comparison with yogurt using mixed culture with W. cibaria (in situ) and traditional starter culture (control). The results showed that the addition of 2% EPS significantly improved syneresis (14.31%) compared to co‐culture (27.50%) and control (29.80%) as well as increased hardness of yogurt during 2‐week refrigeration. [ABSTRACT FROM AUTHOR]

Banana (Musa acuminata Cavendish Subgroup) cultivation plays a pivotal role in Vietnam's economy. However, the presence of postharvest diseases poses significant challenges as they adversely affect the quality and market value of the crop. The objective of this study was to identify the microbial strains responsible for these diseases through phylogenetic analysis and morphological characterisation. Four fungal isolates including Colletotrichum musae, C. gloeosporioides, Fusarium musae and Lasiodiplodia theobromae were identified as the primary causal agents of fruit rot in postharvest bananas. Re‐infection tests, which were conducted following Koch's postulates on banana samples, confirmed the isolates' significant pathogenicity, leading to weight loss, colour alteration, firmness reduction and acidity changes in the fungal‐infected bananas. These findings hold profound implications for enhancing our understanding of banana diseases in the postharvest stage, which can contribute to the development of effective control measures and mitigation strategies in the future. [ABSTRACT FROM AUTHOR]

The microwave spectra of benzothiazole were measured in the frequency range 2–26.5 GHz using a pulsed molecular jet Fourier transform microwave spectrometer. Hyperfine splittings arising from the quadrupole coupling of the 14N nucleus were fully resolved and analyzed simultaneously with the rotational frequencies. In total, 194 and 92 hyperfine components of the main species and the 34S isotopologue, respectively, were measured and fitted to measurement accuracy using a semi-rigid rotor model supplemented by a Hamiltonian accounting for the 14N nuclear quadrupole coupling effect. Highly accurate rotational constants, centrifugal distortion constants, and 14N nuclear quadrupole coupling constants were deduced. A large number of method and basis set combinations were used to optimize the molecular geometry of benzothiazole, and the calculated rotational constants were compared with the experimentally determined constants in the course of a benchmarking effort. The similar value of the χcc quadrupole coupling constant when compared to other thiazole derivatives indicates only very small changes of the electronic environment at the nitrogen nucleus in these compounds. The small negative inertial defect of −0.056 uÅ2 hints that low-frequency out-of-plane vibrations are present in benzothiazole, similar to the observation for some other planar aromatic molecules.

This paper is intended to elucidate the efficacy of employing a Geographic Information Systems (GIS) methodology to investigate the spatial interrelations among migration flows, housing prices, age demographics, and geographical distances. Utilizing data on migration flows and housing prices from Greater Manchester, UK, in 2011, in this study, we performed statistical analyses and generated a suite of visual mappings to illustrate the spatial dynamics between migration patterns, distances, age brackets, and the segmentation of migration destinations by housing price tiers. The findings reveal pronounced spatial associations among migration destinations, underscored by the interplay of housing price levels with age categories, distance intervals, or the origination points tied to specific housing price ranges. This GIS-based analytical framework offers policy-makers and urban planners a powerful tool for discerning distinct migration trends and locales, thereby facilitating more informed decision-making processes. [ABSTRACT FROM AUTHOR]

This study aimed to explore the spatial interaction between search flow and house price levels. It utilized migration flow data from 2011 and house price data from the same year in Greater Manchester, United Kingdom. The methodology included Chi-square tests and a series of visual maps to explore and visualize the relationship between current areas and search areas. The study examined five house price ranges with matches and mismatches between search patterns and current patterns and tried to illuminate the underlying causes. The research results could prove beneficial for policymakers and planners in discerning distinct migratory patterns and geographical regions, thereby facilitating the formulation of well-informed decisions. [ABSTRACT FROM AUTHOR]

The structure and interactions of oxygenated aromatic molecules are of atmospheric interest due to their toxicity and as precursors of aerosols. Here, we present the analysis of 4-methyl-2-nitrophenol (4MNP) using chirped pulse and Fabry–Pérot Fourier transform microwave spectroscopy in combination with quantum chemical calculations. The rotational, centrifugal distortion, and 14N nuclear quadrupole coupling constants of the lowest-energy conformer of 4MNP were determined as well as the barrier to methyl internal rotation. The latter has a value of 106.4456(8) cm−1, significantly larger than those from related molecules with only one hydroxyl or nitro substituent in the same para or meta positions, respectively, as 4MNP. Our results serve as a basis to understand the interactions of 4MNP with atmospheric molecules and the influence of the electronic environment on methyl internal rotation barrier heights.

The rotational spectra of coffee furanone (2-methyltetrahydrofuran-3-one) have been measured in the frequency range from 2.0 to 26.5 GHz using a molecular jet Fourier transform microwave spectrometer. Quantum chemical calculations used for the conformational analysis yielded two stable twist conformers, which were described using the Cremer-Pople notation for five-membered rings. The experimental spectrum of the more stable conformer with the methyl group in equatorial position was assigned and fitted using a rigid rotor model with centrifugal distortion corrections. The spectra of all five 13C-isotopologues could be observed in natural abundance. The carbon atom structure was experimentally deduced using Kraitchman's equations and compared with the structure calculated by quantum chemistry. Key words: rotational spectroscopy, conformational analysis, structure determination, five-membered ring. Resume : Nous mesurons les spectres de rotation du furanone de cafe (2- methyltetahydrofurane-3-un) dans le domaine 2.026.5 GHz, en utilisant un spectrometre microonde a transformee de Fourier avec jet moleculaire. Les calculs de chimie quantique utilises pour l'analyse de configuration donnent deux conformeres stables, qui sont decrits en utilisant la notation de CremerPople pour les anneaux a cinq membres. Le spectre experimental du conformere le plus stable avec le groupe methyl en position equatoriale est assigne et ajuste numeriquement au modele du rotateur rigide avec corrections de distorsions centrifuges. Les spectres des cinq isotopologues C sont observes selon les abondances isotopiques naturelles. La structure de l'atome de carbone est experimentalement deduite a l'aide de l'equation de Kraitchman et comparee avec la structure calculee en chimie quantique. [Traduit par la Redaction] Mots-cles : spectroscopie rotationnelle, analyse de configuration, determination de structure, anneau a cinq membres, 2-methyltetrahgydrofurane-3-un., 1. Introduction Coffee is a very popular drink in the daily life of millions of people in many countries as a first hot beverage in the morning. Several methods have [...]

Large amplitude motions (LAMs) form a fundamental phenomenon that demands the development of specific theoretical and Hamiltonian models. In recent years, along with the strong progress in instrumental techniques on high-resolution microwave spectroscopy and computational capacity in quantum chemistry, studies on LAMs have become very diverse. Larger and more complex molecular systems have been taken under investigation, ranging from series of heteroaromatic molecules from five- and six-membered rings to polycyclic-aromatic-hydrocarbon derivatives. Such systems are ideally suited to create families of molecules in which the positions and the number of LAMs can be varied, while the heteroatoms often provide a sufficient dipole moment to the systems to warrant the observation of their rotational spectra. This review will summarize three types of LAMs: internal rotation, inversion tunneling, and ring puckering, which are frequently observed in aromatic five-membered rings such as furan, thiophene, pyrrole, thiazole, and oxazole derivatives, in aromatic six-membered rings such as benzene, pyridine, and pyrimidine derivatives, and larger combined rings such as naphthalene, indole, and indan derivatives. For each molecular class, we will present the representatives and summarize the recent insights on the molecular structure and internal dynamics and how they help to advance the field of quantum mechanics.