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Thalassemia is a genetic blood disorder requiring life-long blood transfusions. This process often results in iron overload and can be treated by an iron-chelating agent, like deferiprone (3-hydroxy-1,2-dimethylpyridin-4-one), C7H9NO2, in an oral formulation. The first crystal structure of deferiprone, (Ia), was reported in 1988 [Nelson et al. (1988). Can. J. Chem. 66, 123–131]. In the present study, two novel polymorphic forms, (Ib) and (Ic), of deferiprone were identified concomitantly with polymorph (Ia) during the crystallization experiments. Polymorph (Ia) was redetermined at low temperature for comparison of the structural features and lattice energy values with polymorphs (Ib) and (Ic). Polymorph (Ia) crystallized in the orthorhombic space group Pbca, whereas both polymorphs (Ib) and (Ic) crystallized in the monoclinic space group P21/c. The asymmetric units of (Ia) and (Ib) contain one deferiprone molecule, while polymorph (Ic) has three crystallographically independent molecules (A, B and C). All three polymorphs have similar hydrogen-bonding features, such as an R 2 2(10) dimer formed by O—H...O hydrogen bonds, an R 4 3(20) tetramer formed by C—H...O hydrogen bonds and π–π interactions, but the polymorphs differ in their molecular arrangements in the solid state and are classified as packing polymorphs. O—H...O and C—H...O hydrogen bonds lead to the formation of two-dimensional hydrogen-bonded parallel sheets which are interlinked by π–π stacking interactions. In the three-dimensional crystal packing, the deferiprone molecules were aggregated as corrugated sheets in polymorphs (Ia) and (Ic), whereas in polymorph (Ib), they were aggregated as a square-grid network. The characteristic crystalline peaks of polymorphs (Ia), (Ib) and (Ic) were established through powder X-ray diffraction analysis. The Rietveld analysis was also performed to estimate the contribution of the polymorphs to the bulk material.

Structure–property correlation is an important aspect in crystal engineering which has direct applications in the development of pharmaceutical solid dosage forms. In this manuscript, we present a combined structural, thermal and computational study of seven new cocrystals and cocrystal solvates of an antipsychotic drug, olanzapine, with three coformers (hydroquinone, resorcinol and catechol) and attempt to understand the effect of solid-state molecular packing on the thermal properties (desolvation and melting behaviour). The cocrystals were designed by utilizing the robust hydrogen-bonded synthons between the drug and coformers, while the cocrystal solvates were obtained by the isostructural replacement of toluene in a previously reported multicomponent structure by benzene, xylene and ethyl benzene. The positional variations of hydroxyl groups in coformer molecules had a remarkable influence on the crystal packing of cocrystals. The olanzapine–hydroquinone (OLZ–HQ) combination in 1 : 1 stoichiometry crystallized as cocrystal solvates that was attributed to the persistent formation of rectangular hydrogen-bonded grid networks with inherent hydrophobic cavities for aromatic guest molecule inclusion. In contrast, the olanzapine–resorcinol (OLZ–RES) and olanzapine–catechol (OLZ–CAT) combinations in 1 : 1 stoichiometry resulted in non-solvated cocrystals and can be classified as pharmaceutical cocrystals. The desolvation patterns of cocrystal solvates were explained based on the structural similarities and dissimilarities, host–guest interactions, void types (closed vs. open), void size (narrow and wide), packing coefficients and boiling points of the guest molecules. Solid-state DFT calculations were performed to assess the desolvation energies, stabilization energies of desolvated systems and lattice energies of all cocrystals and cocrystal solvate systems and the results were correlated with the experimental observations. The solvent molecules play an important role in the structure stabilization, rendering the crystal lattice of the OLZ–HQ structure energetically feasible and compensating for the loss of packing density rather than simply occupying the void space in the crystal structure. The large melting point differences and thermal stabilities of two anhydrous cocrystals (M.P. of OLZ–RES is 196 °C and M.P. of OLZ–CAT is 135 °C) were also explained on the basis of packing coefficients and lattice energy calculations.

A general method for highly functionalized 2-pyrones via a base-mediated sequential vinylogous addition and cyclization of γ-phosphonyl/sulfonyl crotonates and ynones are described. An exclusive E-geometry with respect to the newly generated olefin substituent at C3 of pyrone was observed. Imino glyoxalates and glycine imines similarly reacted with ynones to deliver 3-imino pyrones.

An efficient gold-catalyzed formation of 6-hydroxyindoles from substituted alkynylcyclohexadienones and amines have been developed. In this reaction two new C-N bonds were formed, and moderate to very good yields of the 6-hydroxyindole derivatives were obtained in one pot. This organic transformation tolerates a range of substituted alkynylcyclohexadienones and amines, which resulted in 6-hydroxyindole derivatives selectively.

The spreading characteristics of particle-bearing jets down a gentle slope in a uniform ambient with confined side-walls are reported through a series of laboratory experiments. A round water jet is mixed with solid particles having particle volume fraction ranging between 0% and 0.4%. The jet Reynolds number is varied between Re = 3000 and 8000. We document that the jet front position varies with time t as xf∝t2/3. The jet front propagation in the presence of side-walls is found to be higher than the unconfined case and is attributed to the recirculation due to the confinement that increases the flow inertia and accelerates the flow. The jet propagation is found to be self-similar and is unaffected by the variations in the volume fraction and Re. The sediment pattern near the source, formed by the settling of the particles, exhibits a similar tear-drop shape, which is well-predicted using the unconfined jet theory that assumes a Gaussian velocity profile. The results have implication in engineering and environmental flows, where higher jet propagation rate for confined jets should be modeled accurately without modifying the sedimentation dynamics.

Attempts to obtain new cocrystals of nonsteroidal antiandrogenic drug nilutamide produced alternative polymorphic forms of the compound (Form II and Form III) and their crystal structures were elucidated by single-crystal X-ray diffraction. Apart from the cocrystallization technique, lyophilization was found to be an effective strategy for achieving polymorph control of nilutamide, which was difficult to obtain by other methods. The physicochemical properties and relative stability of the commercial Form I and newly obtained Form II were comprehensively investigated by a variety of analytical methods (thermal analysis, solution calorimetry, solubility, and sublimation), whereas for Form III, only a handful of experimental parameters were obtained due to the elusive nature of the polymorph. Form I and Form II were found to be monotropically related, with Form I being confirmed as the thermodynamically most stable solid phase. In addition, the performance of different DFT-D and semi-empirical schemes for lattice energy calculation and polymorph energy ranking was compared and analysed. Lattice energy calculations using periodic DFT at B3LYP-D3/6-31(F+)G(d,p) and PBEh-3c/def2-mSVP levels of theory were found to provide the most accurate lattice energy values for Form I against experimental data, while PIXEL and PBEh-3c/def2-mSVP were the only methods that predicted the correct order of stability of Forms I and II.

An experimental measure of irreversible mixing efficiency, $R\phantom{\rule{0}{0ex}}{i}_{f}^{*}$, for a lock-exchange gravity current is presented. The results show that mixing efficiency increases and is sustained in the presence of strong stratification provided the flow energy is high. Following this, various turbulence regimes are mapped based on turbulent Froude number and turbulent Reynolds number. Additionally, $R\phantom{\rule{0}{0ex}}{i}_{f}^{*}$ is shown to have a strong dependence on turbulence regime and molecular effects induced by Prandtl number.

Novel laboratory experiments are configured to study convective dynamics and heat transport characteristics in a non-homogeneously heated rotating annulus. The bidirectional temperature gradients are obtained by imposing a constant cold temperature on inner wall and a constant high temperature along the periphery at the bottom using an aluminium strip of width, h = 5 mm. OpenFOAM simulations are carried out to study convective dynamics in the above-mentioned configuration in a 2D axisymmetric plane to mimic a r − z plane of the real experimental set-up. The parameter range for simulation is Ra = \(3.11\times {10}^{8}\) and Ta = 0–1.06 × 108. Temperatures on outer and inner walls are kept as 302 K and 292 K, respectively. The working fluid is water with a Prandtl number, Pr = 7. Vertical temperature profiles show decreasing impact of thermal forcing with increasing elevation. OpenFOAM simulation combined with experimentally obtained thermal results indicates coexistence and interplay of thermal plumes and baroclinic waves.

Laboratory experiments are conducted to examine the evolution of and sedimentation from a particle-bearing jet advancing along a horizontal or downward-sloping boundary underlying a uniform-density ambient fluid. The jet front advances along the bottom while exhibiting a self-similar profile. As the jet propagates downstream, particles settle out, resulting in a teardrop-shaped sediment bed whose geometric parameters are measured non-intrusively using a light attenuation technique. The bed shape is well represented by the theory that assumes a Gaussian radial profile of velocity within the jet and accounts for the bedload transport of particles after they settle. In particular, the bed length is given by , suggesting that the morphology of the bed non-negligibly influences particle settling.

A series of rotating convection experiments have been conducted in a novel configuration, which comprises a cylindrical annulus with spot heating on the bottom outer edge and uniform cooling on the inner surface. Such a system provides bi-directional thermal gradients in both radial and vertical directions, thereby reenacting the thermal gradient patterns encountered in the atmosphere. Bulk heat transfer characteristics are studied by quantifying the overall Nusselt number, Nu, for a range of Taylor number, Ta, heating rate, Q, and Rayleigh number, Ra. Temperature measurements are carried out at different locations with the help of thermocouples. The Nusselt number is found to be quite sensitive to the buoyancy and relatively insensitive to the rotation rate. The correlation for Nu as a function of Ra revealed different power law exponents for low and high Ta values. The varying exponent is attributed to the presence of baroclinic eddies at high Ta, which in turn is verified with the help of flow visualization. The heat transfer characteristics in this new configuration are significantly different compared to other conventional rotational convection systems, where thermal gradients are present in only one direction.

This technical brief presents a flow separation mitigation device, called cavity-recirculator that can be used to control flow separation during shock wave–boundary layer interaction (SBLI) in high-speed intake flows. The cavity-recirculator isolates the flow separation bubble generated at the SBLI spot, thereby thinning the boundary layer and reducing the blockage of the inviscid stream in the duct. The device has a potential application in scramjet engine intakes/isolators. The cavity-recirculator was tested on a single-ramp-compression intake model in a hypersonic shock tunnel, in a freestream of Mach 8 (±0.1). The device operation and effectiveness were assessed by flow visualization and pressure measurements in the test model. The measurements and visualization displayed a mitigation of flow separation through an improved flow field with a single shock train and the absence of flow separation shock, in the inlet.

A series of laboratory experiments on energy conserving gravity currents in a lock-exchange facility are conducted for a range of Reynolds numbers, $Re= \frac{U_Fh}{\nu} =$ 485-12270. The velocity and density fields are captured simultaneously using a PIV-PLIF system. A moving average method is employed to compute the mean field and a host of turbulence statistics, namely, turbulent kinetic energy ($K$), shear production ($P$), buoyancy flux ($B$), and energy dissipation ($\epsilon$) during the slumping phase of the current. The subsequent findings are used to ascertain the quantitative values of mixing efficiency, $Ri_{f}$, Ozmidov length-scale ($L_O$), Kolmogorov length-scale ($L_\kappa$), and eddy diffusivities of momentum ($\kappa_m$) and scalar ($\kappa_\rho$). Two different forms of $Ri_{f}$ are characterized in this study, denoted by $Ri_{f}^I=\frac{B}{P}$ and $Ri_{f}^{II}=\frac{B}{B+\epsilon}$. The results cover the entire diffusive regime (3 $

A simple, efficient, and eco-friendly synthetic protocol has been developed for the synthesis of pyranoxanthenes via one pot three-component reaction. This reaction is between aromatic aldehyde, 2,2-dimethylchroman-7-ol and 1,3-cyclohexanedione by using molecular iodine in AcOH as a reaction medium under microwave irradiation. Utilizing this protocol a variety of xanthene derivatives were synthesized in excellent yields. The synthesized compounds were established based on the spectral data and single crystal X-ray diffraction analysis of 6f. The synthesized compounds were evaluated for their in vitro antimicrobial and antioxidant activity. The results clearly demonstrated that compounds 6j, 6m and 6n exhibited significant antibacterial activity against bacterial strains. The results of the molecular docking studies supported the antibacterial activity of the synthesized compounds.

An efficient gold-catalyzed intramolecular rearrangement and cyclization protocol was developed for synthesis of 2,5-dihydrofuran derivatives from O-propargyl β-enaminones. In this organic transformation new C-C and C-O bonds are formed under mild reaction conditions; this includes the formation of a quaternary centre.

An efficient gold-carbene promoted generation of tetraarylmethane derivatives from enynones and indoles was accomplished by the formation of a new C-O bond and two C-C bonds. It is significant that (2-furyl) gold-carbene assisted addition of two nucleophiles resulted in the formation of tetraarylmethane derivatives with a quaternary centre in moderate to good yields in one pot.

The ocean exchanges heat and mass with the atmosphere in form of shortwave and longwave radiations, precipitation, and evaporation. The regional scale ocean processes governed by this exchange play a vital role in modulating the local dynamics of the Indian Ocean. For instance, the meso-scale eddies and waves control the ocean vertical temperature structure, mixed layer depth, and the thermocline. The Indian Ocean Observing System (IndOOS) recommends the need of proper understanding of heat budget in the Indian Ocean to resolve the mesoscale and submesoscale processes, which trigger large scale ocean circulation, cyclonic eddies, plumes etc. In a regional domain, the stability of ocean also depends on the local parameters, namely, wind pattern, precipitation, runoff and exchange of heat and mass fluxes near the domain boundary. The main objective of this study is to understand the effect of atmospheric wind and solar radiation on the ocean surface and sub-surface characteristics using Modular Ocean Model (MOM5).A regional domain in the Bay of Bengal (BoB) is selected, which has unique features, such as, large amount of freshwater flux, seasonal wind reversal and high amount of solar radiation due the geographic location. The dynamics in BoB is important for understanding the Indian summer and winter monsoon seasons and associated weather patterns. A regional ocean modelling approach is adopted using MOM5 with horizontal grid resolution (0.250) while maintaining the vertical grid-size as 1m near the surface region which increases with depth. For the regional domain, radiation open boundary condition (OBC) is implemented on three lateral boundaries of domain, based on the technique proposed by Orlanski (1976). The OBC at the lateral boundaries help in smooth exchange of current and tracers. K-profile parameterization (KPP) vertical mixing scheme is used that accounts for effects of shear, wave breaking, and double diffusion. The model is started from a state of rest and simulated for a period of 10 years using 6-hourly solar radiation (Japanese 25-year reanalysis (JRA-25)) and daily averaged wind stress (SODA reanalysis) dataset. After five years of model spin-up, the last five years of simulated output is considered to ensure consistency of model results. Heat budget calculation shows good agreement with WHOI OA Air-Sea Fluxes (OAFlux). Smooth exchange of mass and fluxes is observed near boundary, which confirms successful implementation of OBC. Implementation of KPP scheme enhances mixing in the upper ocean layers with more realistic thermocline formation and turbulent kinetic energy (TKE). The model is able to mimic the seasonal variability in the ocean currents enforced due to winds. The Sea Surface Temperature (SST) is in good agreement with SODA reanalysis data.A plume like mesoscale feature in the SST plot is captured in the present study (that is also observed in microwave SST), but found to be missing in earlier BoB study with sponge boundary conditions. Finer scale resolution (0.1250) study is in progress, which is expected to show secondary mesoscale structures and their evolution. The results from this study would help in better understanding of the influence regional-scale processes on local ocean dynamics.

2-Aryl 5-hydroxy benzo[d]oxazoles were designed as potential anticancer agents. A one-pot synthesis of these compounds dispenses the need for ortho-disubstituted precursor, aminophenol and proceeds via C N formation as a key step followed by C O cyclization to form benzo[d]oxazoles. The single crystal X-ray diffraction study was used to confirm the molecular structure of a representative compound unambiguously. All of these compounds were evaluated for their anti-proliferative properties in vitro against five cancer cell lines as well as noncancerous cells. Most of these compounds showed selective growth inhibition of cancer cells and few of them were found to be promising with IC50 values in the range of 0.8–2.8 μM, comparable to the known anticancer drug doxorubicin.

A chiral bifuntional thiourea catalyzed diastereo- and enantioselective Michael addition followed by an intramolecular Aldol reaction of 3-indolinone-2-carboxylates with cyclohexenone has been accomplished using a chiral thiourea catalyst. It is a novel strategy for the construction of chiral bridged tricyclic hydrocarbazole derivatives bearing four contiguous stereocenters with excellent diastereo- and enantioselectivity.

The vertical release of a lighter buoyant fluid, commonly referred to as a forced plume, into dense environment is a common occurrence in ocean and atmosphere. Such releases may have heterogeneity in them in form of particles with varied size, shape, and volume fraction. Normally in field conditions, the particle size ranges from a few microns to millimetres, and the volume fraction ranges from $$\phi _{v}=0.1{-}10$$ %. In this study, the effects of low values of $$\phi _{v}$$ (corresponding to a two-way coupled system) on the dynamics and structure of a plume umbrella cloud formed in a linearly stratified ambient were examined. Spherical particles with mean diameter $$d_{p}=100\, \upmu \hbox {m}$$ , density, $$\rho _{p}=2500\, \hbox {kg}\,\hbox {m}^{-3}$$ , and $$\phi _{v}=0{-}0.7\%$$ were injected along with the lighter plume fluid. Due to the phenomena of “particle fall-out” and “particle re-entrainment”, it was observed that a plume trough characterized by radius, $$R_{c}$$ , and depth, $$L_p$$ , forms below the neutral buoyant layer of an umbrella cloud. The plume trough formation is linked to the draw-down of the fluid from the neutral buoyant layer by the sedimenting particles. This trough either sustains or collapses depending on the plume conditions at the source, namely, the diameter $$d_{0}$$ , fluid buoyancy, $$g^{\prime }_{0}$$ , vertical velocity, $$W_{0}$$ , and $$\phi _{v}$$ . In all the experiments, $$g^{\prime }_{0}$$ and $$d_{0}$$ were kept constant while $$\phi _{v}=0{-}0.7\%$$ and $$W_{0}=0.2{-}0.65 \,\hbox {m}\,\hbox {s}^{-1}$$ were varied. The experiments revealed that the sustaining and collapsing trough regimes could be qualitatively demarcated based on a source effective Richardson number, $$Ri^{*}_{0}$$ , that accounts for the combined effect of $$\phi _{v}$$ and $$W_{0}$$ . It was found that when $$Ri^{*}_{0}