Rotational asymmetry of reactant concentration and its evolution in a circulating fluidized bed riser

Rotational asymmetric distribution of reactant (ozone) concentration and its evolution along with the gas-solid reactive flow were studied in a 76 mm i.d., 10.2 m high circulating fluidized bed (CFB) riser reactor. The superficial gas velocity ranged from 3 to 5 m/s and the solids circulation rates were 50 and 100 kg/(m² s). Experimental results show that the asymmetry of reactant distribution can extend to a height close to the length of flow developing zone of the CFB riser reactor and then disappears. Based on the hydrodynamics of the gas and solid phases in the solids entrance region, this asymmetry can be attributed to the effect of the solids entrance structure.     

Ile‐Lys‐Val‐ala‐Val (IKVAV) peptide for neuronal tissue engineering

Despite the great advances in microsurgery, some neural injuries cannot be treated surgically. Stem cell therapy is a potential approach for treating neuroinjuries and neurodegenerative disease. Researchers have developed various bioactive scaffolds for tissue engineering, exhibiting enhanced cell viability, attachment, migration, neurite elongation, and neuronal differentiation, with the aim of developing functional tissue grafts that can be incorporated in vivo. Facilitating the appropriate interactions between the cells and extracellular matrix is crucial in scaffold design. Modification of scaffolds with biofunctional motifs such as growth factors, drugs, or peptides can improve this interaction. In this review, we focus on the laminin‐derived Ile‐Lys‐Val‐Ala‐Val peptide as a biofunctional epitope for neuronal tissue engineering. Inclusion of this bioactive peptide within a scaffold is known to enhance cell adhesion as well as neuronal differentiation in both 2‐dimensional and 3‐dimensional environments. The in vivo application of this peptide is also briefly described.     

X-ray crystal structure of [VO(DPA)(H2O)2]·2H2O (DPA=Dipicolinate dianion)

The X-ray crystal structure of the trans-diaqua complex [VO(DPA)(H2O2)]·2H2O (1) (DPA=dipicolinate dianion) has been determined. Comparison with the known structure of [VO(DPA)(o-phen)]·3H2O (2), obtained from (1) by displacement of the two coordinated aqua molecules, shows that the coordination sphere around vanadium is reorganised during this reaction.     

Synthesis, characterisation and reactivity of trans-[Ru(L)(PPh3)Br2]; L=2-pyridyl-N-(2′-methylthiophenyl)methyleneimine: Crystal structure of trans-[Ru(L)(PPh3)Br2]

Reaction of Ru(PPh₃)₂Br₂ with the NNS chelating tridentate ligand 2-pyridyl-N-(2′-methylthiophenyl)methyleneimine (L) led to the isolation of the ruthenium(II) complex [Ru(L)(PPh₃)Br₂]. Reactivity of this complex with different bidentate chelating ligands revealed that the products are quite different from those obtained by reacting Ru(L)(PPh₃)Cl₂ (the corresponding cis dichloro complex) with the same ligands under comparable conditions. The mixed chelates were isolated and characterised by elemental analysis, magnetic moment measurement and by different spectroscopic methods along with their precursor. Electrochemistry of the complexes was examined by cyclic voltammetry using a platinum working electrode and a Ag/AgCl electrode as reference. The crystal structure of [Ru(L)(PPh₃)Br₂] disclosed that, unlike Ru(L)(PPh₃)Cl₂, the two bromo ligands are in trans position and this explained the difference in its reactivity pattern from the corresponding chloro complex.     

Dynamic modelling of dissolved oxygen in the creeks of Sagar island,Hooghly–Matla estuarine system,West Bengal,India

Hooghly–Matla estuarine ecosystem is one of the largest estuarine ecosystems of the world. Sagar island is the largest delta in this estuarine complex. This island is criss-crossed by small and large creeks with mangrove vegetation and all are connected to the principal estuarine water. Decomposition of mangrove litter in soil is major source of inorganic nutrient to phytoplankton of the adjacent creeks. Deforestation of mangrove affects the primary production, which in turn reduces the availability of dissolved oxygen for the organisms residing in the estuary. Considering the importance of dissolved oxygen in various aspects of aquatic life, a dynamic model of dissolved oxygen at Sagar island of Hooghly–Matla estuarine complex with the help of single dimension differential equation is proposed in the present paper. Different physical, chemical and biological factors such as solar irradiance, temperature, salinity of water, particulate organic matter, re-aeration, wind velocity, phytoplankton and zooplankton, which control the fluctuation of dissolved oxygen, are included in the present model. Most of the parameter values are collected directly from the field surveys. The parameter values which are not able to collect from the field, obtained from literatures are calibrated. To make the model realistic it is properly validated with observed data and to know the statistical significance, chi square goodness fit test is performed. Field surveys are performed over two years. During calibration and validation, two sets of data (first year and second year data) are used. Chi-square values are 5.97 and 6.17 for first and second sets of data respectively (p < 0.05). Sensitivity analysis reveals that optimal light intensity is the most sensitive parameter for dissolved oxygen dynamics. Results also show that wind velocity, solar irradiation, salinity of water and temperature are important factors for controlling the dynamics of dissolved oxygen. Macrophytes have very little contribution to oxygen production in the creeks of Sagar island. Model reveals that low dissolved oxygen in the creek water is one of the causes of decline in fish population of the estuary.     

Isomeric Diruthenium Complexes Bridged by Deprotonated Indigo in cis and trans Configuration

The doubly deprotonated form L^2? of indigo=H₂L can bind two [Ru(acac)₂] complex fragments in the cis ( 1 ) and trans configuration ( 2 ), as evidenced from crystal structure analysis. While the latter type of N,O; N ^’ ,O ^’ coordination has been observed earlier, for example, with [Ru(bpy)₂]²⁺, leading to two equivalent six‐membered ring chelates, the cis arrangement in 1 is observed here for the first time in a dinuclear complex, producing one five‐membered ring chelate with N,N ^’ coordination and one seven‐membered chelate with O,O ^’ coordination. The different structures of the isomers result in differing electrochemical and spectroelectrochemical (EPR, UV‐Vis‐NIR) responses for various accessible charge states 1 ⁿ and 2 ⁿ, n=–, 0, +, 2+. The associated electronic structures were analyzed by DFT (structures, spin density) and TD‐DFT calculations (electronic transitions), revealing mainly metal‐based reduction but largely indigo ligand‐based oxidation of both neutral precursors.     

Recent Development of Brain Organoids for Biomedical Application

Over the years, scientists have studied the behavior and anatomy of many animals to understand the own species. However, despite the continuous efforts, it is often difficult to know for certain how the brain works due to the differences between the brains of animals and the human brain. While the use of animal models for research continues, the origin of human cognition and neurological disorders needs further elucidation. To that end, in vitro organoids that exhibit in vivo characteristics of the human brain have been recently developed. These brain-like organoids enable researchers to dive deeper into understanding the human brain, its neurological structures, and the causes of neurological pathologies. This paper reviews the recent developments in the regeneration of brain-like organoids using Matrigel and other alternatives. Further, gel-free methods that may enhance the regeneration process of organoids are discussed. Finally, the vascularized brain organoid growth and development in both in vitro and in vivo conditions are detailed.     

Determination of gold by substoichiometric extraction with N-thioacetyl benzamide

Estimation of gold has been successfully carried out by substoichiometric radiochemical solvent extraction method using a newly designed organic moiety, N-thioacetyl benzamide as extractant and chloroform as solvent at aqueous pH 4. The interference effects of different closely related diverse ions like Fe(III), Cu(II), Co(II), Zn(II), Ni(II) etc. were also critically studied. The validity of this method has been verified by the study of recovery of gold in mud samples.     

Characteristics of metal/p-SnS Schottky barrier with and without post-deposition annealing

With growing interest in SnS for solar photovoltaic device fabrication, the barrier characteristics to this semiconductor with respect to different metal contacts have become increasingly important. In this work we have studied barrier characteristics of polycrystalline SnS thin films metallized with indium, aluminium, copper and silver under different annealing conditions. Indium has been observed to form ohmic contact to p-SnS under all annealing conditions. With the other three metals, Schottky diodes were fabricated and subsequently the contact parameters were extracted under forward bias using indium top contact under different annealing conditions. Although aluminium formed Schottky contact to polycrystalline SnS, annealing at 350 °C rendered it ohmic. EDX analysis confirmed desulfurization from SnS thin films due to annealing. Breakdown voltages of the Al/SnS Schottky barrier diode were determined and were in the decreasing trend with higher annealing temperature, supporting the increase in the doping profile with annealing temperature. Photoluminescence spectra of SnS films were studied and correlated to surface trap centers generated due to annealing.     

Critical evaluation of micellization behavior of nonionic surfactant MEGA 10 in comparison with ionic surfactant tetradecyltriphenylphosphonium bromide studied by microcalorimetric method in aqueous medium

The micellization behavior of MEGA 10 has been studied at nine different temperatures by isothermal titration calorimetry (ITC), and thermodynamics of the process have been evaluated and examined in detail. The aggregation number of the nonionic surfactant has been estimated from the ITC results by a simulation procedure based on the mass action principle of micellization of the surfactant. The cmc of MEGA 10 has shown a minimum in temperature dependence as observed for ionic surfactants. For a comparison, the cmc and related thermodynamic parameters of an ionic surfactant, tetradecyltriphenylphosphonium bromide (C(14)TPB) studied at several temperatures in aqueous medium has been considered. The contributions of the headgroups of both the surfactants to the free energies of their respective micellization have been deciphered and presented.