Application of Artificial Neural Network for Yield Prediction of Lipase-Catalyzed Synthesis of Dioctyl Adipate

In this study, an artificial neural network (ANN) trained by backpropagation algorithm, Levenberg–Marquadart, was applied to predict the yield of enzymatic synthesis of dioctyl adipate. Immobilized Candida antarctica lipase B was used as a biocatalyst for the reaction. Temperature, time, amount of enzyme, and substrate molar ratio were the four input variables. After evaluating various ANN configurations, the best network was composed of seven hidden nodes using a hyperbolic tangent sigmoid transfer function. The correlation coefficient (R ²) and mean absolute error (MAE) values between the actual and predicted responses were determined as 0.9998 and 0.0966 for training set and 0.9241 and 1.9439 for validating dataset. A simulation test with a testing dataset showed that the MAE was low and R ² was close to 1. These results imply the good generalization of the developed model and its capability to predict the reaction yield. Comparison of the performance of radial basis network with the developed models showed that radial basis function was more accurate but its performance was poor when tested with unseen data. In further part of the study, the feedforward backpropagation model was used for prediction of the ester yield within the given range of the main parameters.     

Shahidine, a novel and highly labile oxazoline from Aegle marmelos: the parent compound of aegeline and related amides

A rare alkaloid, shahidine (1), having an unstable oxazoline core has been isolated as a major constituent from the fresh leaves of Aegle marmelos. It is moisture-sensitive, and found to be the parent compound of aegeline and other amides, however, it is stable in dimethyl sulfoxide. Its structure was established by spectroscopic analysis. Biogenetically, oxazolines may be considered as the precursor of hydroxy amides and oxazoles found in plants. Shahidine (1) showed activity against a few Gram-positive bacteria.     

Di-organoiron mixed valent complexes featuring "(eta2-dppe)(eta5-C5Me5)Fe" endgroups: smooth class-III to class-II transition induced by successive insertion of 1,4-phenylene units in a butadiyne-diyl bridge

The synthesis and study of a new redox family of symmetric dinuclear iron(II/III) complexes featuring "(eta(2)-dppe)(eta(5)-C(5)Me(5))Fe(CC)" endgroups connected by a bis(diethynyl)-4,4'-biphenyl spacer are reported. The solid-state structures were determined (X-rays) for the homovalent Fe(II)/Fe(II) and Fe(III)/Fe(III) parents. In contrast, the mixed valent (MV) complex 5[PF(6)] has a low thermodynamic stability (Kc around 10) and cannot be isolated in a pure form, but was studied in solution. According to the Robin and Day classification, it constitutes a remarkable example of well-behaved weakly coupled class-II organometallic MV compound. The photodriven metal-metal electron-transfer process takes place over ca. 16 A and corresponds to an electronic coupling of ca. 150 cm(-1) with a reorganization energy of ca. 6250 cm(-1) in dichloromethane. A similar investigation was also conducted in the near-IR range for the known and much more stable MV analogue 3[PF(6)] featuring the 1,4-phenyl unit instead of the 4,4'-biphenyl one (K(c) = 2.6 10(4)). The latter also exhibits a localized valency, but presents a very intense intervalence charge-transfer band (IVCT) with a cutoff on the low-energy side. A much stronger electronic coupling is derived (ca. 1700 cm(-1)) from the band shape for this MV complex in the frame of the two-level model. Although slowed, the electron exchange is not disrupted by insertion of an additional para-phenylene moiety into a 1,4-diethynylaryl bridge. Thus, starting from a compound with a butadiyne-diyl spacer, stepwise para-phenylene insertions in the bridge produce a smooth Class-III to Class-II transition for the corresponding MV complexes.     

Test of a new tip material for Langmuir probe diagnostic

The objective of the work is to test a nickel–chrome alloy as a probe tip material for characterization of discharge plasmas. In order to meet the objective, a symmetric triple Langmuir probe diagnostic system and an associated driving circuit are designed and tested in an inductively coupled plasma generated by a 13.56-MHz radio frequency source coupled with an automated impedance match network. This probe is used to measure the electron temperature, electron number density, and ion saturation current as functions of the input power of the radio frequency source and the filling gas pressure. An increasing trend is noticed in the electron temperature and electron number density with an increase in the input power, whilst a decreasing trend is evident in these parameters with an increase in the nitrogen gas pressure. The overall inaccuracies in electron temperature and electron number density measurements are 5–12% and 3–13%, respectively.     

Conservation laws for some compacton equations using the multiplier approach

This paper is an application of the variational derivative method to the derivation of the conservation laws for partial differential equations. The conservation laws for (1+1) dimensional compacton k(2,2) and compacton k(3,3) equations are studied via multiplier approach. Also the conservation laws for (2+1) dimensional compacton Zk(2,2) equation are established by first computing the multipliers.     

Acceleration of Adventitious Shoots by Interaction Between Exogenous Hormone and Adenine Sulphate in Althaea Officinalis L.

In the current study attempts were made to investigate the effects of three different phases of callus induction followed by adventitious regeneration from leaf segments (central and lateral vein). Callus induction was observed in Murashige and Skoog’s (MS) medium supplemented with 15.0 μM 2,4-dichloro phenoxy acetic acid (2,4-D). Adventitious shoot buds formation was achieved on MS medium supplemented with 7.5 μM 2,4-D and 20.0 μM AdS in liquid medium as it induced 19.2?±?0.58 buds in central vein explants. Addition of different growth regulators (cytokinins—6-benzyladenine, kinetin and 2-isopentenyl adenine alone or in combination with auxins—indole-3-acetic acid, indole-3-butyric acid and α-naphthalene acetic acid, improved the shoot regeneration efficiency, in which 5.0 μM 6-benzyl adenine along with 0.25 μM α-naphthalene acetic acid was shown to be the most effective medium for maximum shoot regeneration (81.3 %) with 24.6 number of shoots and 4.4?±?0.08 cm shoot length per explant. Leaf culture of central veins led to better shoot formation capacity in comparison to lateral vein. Rooting was readily achieved on the differentiated shoots on 1/2 MS medium augmented with 20.0 μM indole-3-butyric acid. The plants were successfully hardened off in sterile soilrite followed by their establishment in garden soil with 80 % survival rate.     

1,2-Bis-(2-benzimidazolyl)-1,2-ethanediol and 1,4-bis-(2-benzimidazolyl)-1,2,3,4-butanetetraol PdCl2 complexes

The 1,2-bis-(2-benzimidazolyl)-1,2-ethanediol (EH₂) and 1,4-bis-(2-benzimidazolyl)-1,2,3,4-butanetetraol (TH₄) ligands form 4-coordinate mono- and bi-metallic complexes with PdCl₂, respectively. In Pd(EH₂)Cl₂ the ligand acts as a bidentate through two of the nitrogen atoms. On the other hand, in Pd₂(TH₄)Cl₄ the ligand coordinates to two palladium atoms through both bis-benzimidazole nitrogen atoms and two oxygen atoms of the hydroxy groups, forming two different isomers. The complexes were characterised by analytical data, magnetic susceptibility, molar conductivity, and also by i.r., ¹H- and ¹³C-n.m.r. spectra.     

Synthesis and characterisation of 1,3-bis(2-benzimidazyl)-2-thiapropane, 1,5-bis(2-benzimidazyl)-3-thiapentane ligands and their PdCl2 complexes

The 1,3-bis(2-benzimidazyl)-2-thiapropane (TP₂) and 1,5-bis(2-benzimidazyl)-3-thiapentane (TP₃) ligands form 5-coordinate square pyramidal monometallic complexes with PdCl₂. In both complexes the ligands act as chelating tridentate, through two of the nitrogen atoms in the imidazole ring and the sulphur atom of the bridging group. The ligands and complexes were characterised by analytical data and by modern spectroscopic methods such as FT-Raman, i.r., ¹H and ¹³C-n.m.r. spectra.