2H-Indazolo[2,1-b]phthalazine-trione derivatives: Inhibition on some metabolic enzymes and molecular docking studies

In this study, substituted 2H-indazolo[2,1-b]phthalazine-1,6,11-trione compounds ( 4a–d ) obtained via one-pot three-component condensation reaction of aromatic aldehydes, cyclic 1,3-dione, and phthalhydrazide in ethanol catalyzed by Y(OTf)₃ showed satisfactory inhibitory effects against some important enzymes. Also, these molecules had K_i values in the row of 185.92 ± 36.03-294.82 ± 50.76 nM vs carbonic anhydrase I (CA I), 204.93 ± 46.90-374.10 ± 83.63 nM against human CA II, 937.16 ± 205.82-1021.83 ± 193.66 nM against α-glycosidase (α-Gly), respectively. For cholinesterase enzymes, the K_i values were found in the range of 47.26 ± 9.62-72.05 ± 19.47 nM against acetylcholinesterase (AChE) and 65.03 ± 9.88-102.83 ± 25.04 nM against butyrylcholinesterase (BChE), respectively. The inhibition effects of these compounds against enzymes whose name are AChE, BChE, α-Gly, hCA I, and hCA II, were compared with control molecules like tacrine, acarbose, and acetazolamide.     

Spectral image adaptation and visual experience of DBA/PMMA

High resolution S0-->Sn and T1-->Tn electronic absorptions and B-type delayed fluorescence of 1,2,7,8-dibenzanthracene in polymethylmethacrylate (PMMA) were experimentally observed by flash and laser flash photolysis technique. Dibenzanthracene (hereafter DBA) molecules were excited in a two-step process. In the first step, an excited singlet is created, which undergoes intersystem crossing to triplet state, then T-T absorption creates an excited triplet dibenzanthracene molecule, which returns to the first excited singlet level by intersystem crossing. The re-created first excited singlet of dibenzanthracene decays back to the ground state by emitting B-type of delayed fluorescence, which was observed at the same emission band of prompt (normal) fluorescence, and R-, E-, P-types of delayed fluorescences. For normal fluorescence, S1 state is decaying to S0 ground state. For E- and P-type of delayed fluorescences, T1 state is decaying to S0 via S1 state, and for B-type of delayed fluorescence, T2 state is decaying to S0 via S1 state. The spectrum image showing the absorption/emission bands mentioned was also examined by image processing techniques in order to improve the visual experience of each band by localizing to a specific region of interest (ROI). Experimental results illustrate how the exact location of emission/absorption bands was clearly extracted from the spectral image and further improvements in the visual detection of absorption/emission bands.     

Entropy generation of radial rotation convective channels

The exchange of heat between two fluids is established by radial rotating pipe or a channel. The hotter fluid flows through the pipe, while the cold fluid is ambient air. Total length of pipe is made up of multiple sections of different shape and position in relation to the common axis of rotation. In such heat exchanger the hydraulic and thermal irreversibility of the hotter and colder fluid occur. Therefore, the total entropy generated within the radial rotating pipe consists of the total entropy of hotter and colder fluid, taking into account all the hydraulic and thermal irreversibility of both fluids. Finding a mathematical model of the total generated entropy is based on coupled mathematical expressions that combine hydraulic and thermal effects of both fluids with the complex geometry of the radial rotating pipe. Mathematical model follows the each section of the pipe and establishes the function between the sections, so the total generated entropy is different from section to section of the pipe. In one section of the pipe thermal irreversibility may dominate over the hydraulic irreversibility, while in another section of the pipe the situation may be reverse. In this paper, continuous analytic functions that connect sections of pipe in geometric meaning are associated with functions that describe the thermo-hydraulic effects of hotter and colder fluid. In this way, the total generated entropy of the radial rotating pipe is a continuous analytic function of any complex geometry of the rotating pipe. The above method of establishing a relationship between the continuous function of entropy with the complex geometry of the rotating pipe enables indirect monitoring of unnecessary hydraulic and thermal losses of both fluids. Therefore, continuous analytic functions of generated entropy enable analysis of hydraulic and thermal irreversibility of individual sections of pipe, as well as the possibility of improving the thermal–hydraulic performance of the rotating pipe consisting of n sections. Analytical modeling enabled establishing of a mathematical model of the total generated entropy in a radial rotating pipe, while the generated entropy of models with radial rotating pipe were determined by experimental testing, with comparisons of the achieved results.     

Synthesis of polyamines via hydroaminomethylation of alkenes with urea--a new, effective and versatile route to dendrons and dendritic core molecules

Polyamines, structurally related to putrescines and spermidines, are easily obtainable via hydroaminomethylation of methylallylphthalimide with primary or secondary amines. In addition, hydroaminomethylation of monoolefins with urea as a synthetic equivalent for ammonia, in contrast to other methods (e.g. the alkylation of ammonia or ammonium salts), allows selective synthesis of symmetric tertiary amines. By combining both methods dendrons and dendrimer cores are conveniently obtained.     

Metalloradical EPR Signals from the YZ·S-State Intermediates in Photosystem II

The redox-active tyrosine residue (Y_Z) plays a crucial role in the mechanism of the water oxidation. Metalloradical electron paramagnetic resonance (EPR) signals reflecting the light-induced Y_Z· in magnetic interaction with the CaMn₄-cluster in the particular S-state, Y_Z·S_X intermediates, have been found in intact photosystem II. These so-called split EPR signals are induced by illumination at cryogenic temperatures and provide means to both study the otherwise transient Y_Z· and to probe the S-states with EPR spectroscopy. The illumination used for signal induction grouped the observed split EPR signals in two categories: (i) Y_Z in the lower S-states was oxidized by P680⁺ formed via charge separation, while (ii) Y_Z in the higher S-states was oxidized by an excited, highly oxidizing Mn species. Applied mechanistic studies of the Y_Z·S_X intermediates in the different S-states are reviewed and compared to investigations in photosystem II at physiological temperature. Addition of methanol induced S-state characteristic changes in the split signals’ formation which reflect changes in the magnetic coupling within the CaMn₄-cluster due to methanol binding. The pH titration of the split EPR signals, on the other hand, could probe the proton-coupled electron transfer properties of the Y_Z oxidation. The apparent pK _as found for decreased split signal induction were interpreted in the fate of the phenol proton.     

Some useful properties of Legendre polynomials and its applications to neutron transport equation in slab geometry

In this paper, we describe a new scattering kernel and general theoretical scheme for the evolution of the discrete and continuum eigenvalue spectrum in one-dimensional slab geometry neutron transport equation. Firstly, some useful properties of the Legendre polynomials which revealed during the definition of the new scattering kernel are discussed. By using the scattering kernel in one-dimensional neutron transport equation we obtained an integral equation for angular part of the angular flux. For the solution of this integral equation and eigenvalue equations, some comments are given.     

Drying of Large Monolithic Aerogels between Atmospheric and Supercritical Pressures

The objectives of this investigation are to show the feasibility of producing large monoliths with minimal shrinkage at subcritical conditions, and to understand the drying behavior. Crack-free SiO2 monoliths (5.6 cm in diameter and 25 cm in length) were repeatedly dried with little shrinkage (<2%). Some gels showed increasing shrinkage with decreasing pressure. However, this shrinkage was reduced to negligible levels at conditions considerably less than supercritical pressure by increasing both the pore size and the gel strength. This moderate pressure drying (MPD) process may make aerogel fabrication economically more feasible due to reduced pressure chamber costs.     

Syntheses of new polyamine dendrimer units via a tandem hydroformylation/reductive amination sequences

Rh-catalyzed tandem hydroformylation/reductive amination sequences (hydroaminomethylation) starting from olefins are applied to the synthesis of new polyamine dendrimer units using both convergent and divergent strategies in solution as well as on solid support.     

Production of lipase by a newly isolated <Emphasis Type="Italic">Bacillus coagulans</Emphasis> under solid-state fermentation using melon wastes

Summary An extracellular lipase was produced by Bacillus coagulans by solid-state fermentation. Solid waste from melon was used as the basic nutrient source and was supplemented with olive oil. The highest lipase production (78,069 U/g) was achieved after 24h of cultivation with 1% olive oil enrichment. Enzyme had an optimal activity at 37°C and pH 7.0, and sodium dodecyl sulfate increased lipase activity. NH ₄NO₃ increased enzyme production, whereas organic nitrogen had no effect. The effect of the type of carbon sources on lipolytic enzyme production was also studied. The best results were obtained with starch and maltose (148,932 and 141,629 U/g, respectively), whereas a rather low enzyme activity was found in cultures grown on glucose and galactose (approx 118,769 and 123,622 U/g, respectively). Enzyme was inhibited with Mn⁺² and Ni⁺² by 68 and 74%, respectively. By contrast, Ca⁺² enhanced enzyme production by 5%.     

Drying and sintering of sol-gel derived large SiO2 monoliths

This review article summarizes the development of drying and sintering techniques for the production of sol-gel derived, large silica glass components. Gels may be synthesized using particulate or metal alkoxide precursors, or both in combination. Rapid fracture-free drying has been achieved easily with particulate gels because of their large pore size (100–6000 Å). Alkoxide gels, which generally have small pores (<200 Å), were initially difficult to dry without cracking. However, recent studies have shown that large alkoxide gel monoliths can also be dried in reasonably short times (<10 days). During subsequent heat treatment, alkoxide gels tend to have high shrinkage rates, which may cause trapping of hydroxyl ions or organic groups remaining on the gel surface. Although the removal of these species is easier for particulate gels, their large pore size necessitates heating above 1400°C to achieve full consolidation. Sintering at such temperatures was observed to deteriorate glass quality, through crystallization, warping, and/or sagging. Extensive optimization of the entire process has shown that on a laboratory scale, high-optical-quality glass can be produced from both alkoxide and particulate gels. It remains to be seen whether sol-gel process will be feasible for the manufacture of high-quality glass products on a commercial scale.