3-Carb­oxy-2-methoxy­phenyl­boronic acid

The mol­ecular structure of the title compound, 3-COOH-2-CH3O—C6H3B(OH)2 or C8H9BO5, is stabilized in part due to the presence of an intra­molecular O—H⋯O hydrogen bond. In the crystal structure, mol­ecules are linked by inter­molecular O—H⋯O hydrogen bonds, generating a two-dimensional sheet structure aligned parallel to the (11) plane

A Parametric Test based Analysis of State Estimation Techniques under Data Uncertainties

This work examines the statistical analysis of conventional and evolutionary strategies used to solve state estimation problems. All energy management systems use state estimation to determine the operational condition of the system. Moreover, with the rise of the electrical market and the notion of a smart grid, the assessment of system parameters has received considerable attention. Hence an assessment of the efficiency and robustness of various state estimation techniques used to compute the system parameters is very much required. This paper primarily focuses on the parametric tests used to access and compare the robustness of various state estimators. Case studies are conducted on IEEE 6 bus and 14 bus systems. In addition, this paper also provides a statistical evaluation of the performance of evolutionary algorithms with varying upper and lower optimal solution constraints. Furthermore, the algorithms' robustness under conditions of missing and infringed data is also determined. The findings derived from these estimators are compared with the base values, and the percentage error in estimated values is computed and analysed

Bis[3-(dihydroxy­boryl)anilinium] sulfate

In the title compound, 2C6H9BNO2 +·SO4 2−, the dihydroxy­boryl group of one of the two independent boronic acid mol­ecules participates in (B)O—H⋯OB and N—H⋯OB hydrogen bonds, while the second is involved mainly in the formation of the charge-assisted heterodimeric synthon –B(OH)2⋯−O2SO2 −. These aggregates are further connected through N—H⋯Osulfate inter­actions, forming a complex three-dimensional hydrogen-bonded network

Recent Trends Concerning Upconversion Nanoparticles and Near-IR Emissive Lanthanide Materials in the Context of Forensic Applications

Upconversion nanoparticles (UCNPs) are materials that, upon absorbing multiple photons of low energy (e.g. infrared radiation), subsequently emit a single photon of higher energy, typically within the visible spectrum. The physics of these materials have been the subject of detailed investigations driven by the potential application of these materials as medical imaging devices. One largely overlooked application of UCNPs is forensic science, wherein the ability to produce visible 5 light from infrared light sources would result in a new generation of fingerprint powders that circumvent background interference which can be encountered with visible and ultraviolet light sources. Using lower energy, infrared radiation would simultaneously improve the safety of forensic practitioners who often employ light sources in less than ideal locations. This review article covers the development of UCNPs, the use of infrared radiation to visualise fingerprints by the forensic sciences, and the potential benefits of applying UCNP materials over current approaches

Propensity of formation of zipper architecture vs. Lincoln log arrangement in solvated molecular complexes of melamine with hydroxybenzoic acids

Molecular complexes of melamine with hydroxy and dihydroxybenzoic acids have been analyzed to assess the collective role of the hydroxyl (OH) and carboxyl (COOH) functionalities in the recognition process. In most cases, solvents of crystallization do play a major role in self-assembly and structure stabilization. Hydrated compounds generate linear chains of melamine molecules with acid molecules pendant resulting in a zipper architecture. However, anhydrous and solvated compounds generate tetrameric units consisting of melamine dimers together with acid molecules. These tetramers in turn interweave to form a Lincoln log arrangement in the crystal. The salt/co-crystal formation in these complexes cannot be predicted apriori on the basis of Delta pK(a) values as there exists a salt-to-co-crystal continuum

A Parametric Test based Analysis of State Estimation Techniques under Data Uncertainties

837-849This work examines the statistical analysis of conventional and evolutionary strategies used to solve state estimation problems. All energy management systems use state estimation to determine the operational condition of the system. Moreover, with the rise of the electrical market and the notion of a smart grid, the assessment of system parameters has received considerable attention. Hence an assessment of the efficiency and robustness of various state estimation techniques used to compute the system parameters is very much required. This paper primarily focuses on the parametric tests used to access and compare the robustness of various state estimators. Case studies are conducted on IEEE 6 bus and 14 bus systems. In addition, this paper also provides a statistical evaluation of the performance of evolutionary algorithms with varying upper and lower optimal solution constraints. Furthermore, the algorithms' robustness under conditions of missing and infringed data is also determined. The findings derived from these estimators are compared with the base values, and the percentage error in estimated values is computed and analysed

Conformational Polymorphism in a Non-steroidal Anti-inflammatory Drug, Mefenamic Acid

For several years, the non-steroidal anti-inflammatory drug mefenamic acid, <b>MA</b>, has been known to exist as dimorphs (<b>I</b> and <b>II</b>). We report a new metastable polymorph (<b>III</b>) of <b>MA</b> obtained during attempted co-crystallization experiments and establish its stability relationship with existing forms. At elevated temperatures <b>I</b> and <b>III</b> convert to <b>II</b>, as evident from DSC experiments. On the basis of the lattice energy calculations in conjunction with thermal analysis, the stability order is proposed to be <b>I</b> > <b>II</b> > <b>III</b> at ambient conditions, whereas at elevated temperature the order is <b>II</b> > <b>I</b> > <b>III</b>. In either condition <b>III</b> is a metastable form and hence transforms to <b>I</b> at ambient conditions and to <b>II</b> at higher temperatures. Also we report the structural studies of a DMF solvate and a cytosine complex

Molecular basis for the mechanical response of sulfa drug crystals

Comprehension of the nanomechanical response of crystalline materials requires the understanding of the elastic and plastic deformation mechanisms in terms of the underlying crystal structures. Nanoindentation data were combined with structural and computational inputs to derive a molecular-level understanding of the nanomechanical response in eight prototypical sulfa drug molecular crystals. The magnitude of the modulus, E, was strongly connected to the non-covalent bond features, that is, the bond strength, the relative orientation with the measured crystal facet and their disposition in the crystal lattice. Additional features derived from the current study are the following. Firstly, robust synthons well isolated by weak and dispersive interactions reduce the material stiffness; in contrast, the interweaving of interactions with diverse energetics fortifies the crystal packing. Secondly, mere observation of layered structures with orthogonal distribution of strong and weak interactions is a prerequisite, but inadequate, to attain higher plasticity. Thirdly, interlocked molecular arrangements prevent long-range sliding of molecular planes and, hence, lead to enhanced E values. In a broader perspective, the observations are remarkable in deriving a molecular basis of the mechanical properties of crystalline solids, which can be exploited through crystal engineering for the purposeful design of materials with specific properties

Conformational Polymorphism in a Non-steroidal Anti-inflammatory Drug, Mefenamic Acid

For several years, the non-steroidal anti-inflammatory drug mefenamic acid, <b>MA</b>, has been known to exist as dimorphs (<b>I</b> and <b>II</b>). We report a new metastable polymorph (<b>III</b>) of <b>MA</b> obtained during attempted co-crystallization experiments and establish its stability relationship with existing forms. At elevated temperatures <b>I</b> and <b>III</b> convert to <b>II</b>, as evident from DSC experiments. On the basis of the lattice energy calculations in conjunction with thermal analysis, the stability order is proposed to be <b>I</b> > <b>II</b> > <b>III</b> at ambient conditions, whereas at elevated temperature the order is <b>II</b> > <b>I</b> > <b>III</b>. In either condition <b>III</b> is a metastable form and hence transforms to <b>I</b> at ambient conditions and to <b>II</b> at higher temperatures. Also we report the structural studies of a DMF solvate and a cytosine complex