Rudolf KiraljTechnical College in Bjelovar · Nursing Deparment
Rudolf Kiralj
PhD
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74
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Introduction
Publications
Publications (74)
Sulphur is the most abundant microelement in the human body, in the form not only of many organic but also of many inorganic compounds with diverse roles. This review presents inorganic sulphur compounds from the class of endogenous thiocyanate compounds present in the human body. The class is primarily produced from the thiocyanate anion SCN− in e...
Sumpor je nakon kalcija i fosfora najzastupljeniji element u ljudskom tijelu, gdje se nalazi u mnogobrojnim anorganskim i organskim spojevima, a u vrlo malim količinama i u elementarnom stanju. U ovom pregledu prikazani su anorganski spojevi sumpora iz klase endogenih okso-spojeva u ljudskom organizmu, koji ponajprije nastaju enzimskim i neenzimski...
Background:
The photosynthetic apparatus is targeted by various herbicides, including several amides such as diuron and linuron. Considering the need for the discovery of new active ingredients to cope with weed resistance, the synthesis of a series of trifluoromethyl aryl amides is herein described whose inhibitory properties were assessed in vit...
Visoka tehnička škola Bjelovar, Stručni studij sestrinstva Sažetak Kemoterapija je liječenje raka kemijskim sredstvima koja uništavaju zloćudne stanice-citostaticima, antitumorskim kemoterapueticima ili antineoplasticima. Dijele se na citotoksične lijekove (alkilirajuće spojeve, antimetabolite i na razne prirodne produkte-antitumorske antibiotike,...
Introduction: Myasthenia gravis is a rare, neuromuscular and autoimmune disease symptomatology with severe muscle weakness and difficulty in performing everyday activities that significantly affect the overall quality of life. The aim of the research is to determine the quality of life of people affected by present self-limiting disease problems an...
Sign change problem (SCP) in multivariate Quantitative Structure-Activity/Property Relationships (QSAR/QSPR) is the inconsistency in the direction of association between molecular descriptors and the dependent variable. Sign change is observed when the signs of the elements of the reference vector (correlation vector for the data set obtained from...
Even small areas as Bjelovar-Bilogora County (BBC) are affected by increasing local and regional pollution. A large variety of organic compounds exists in all parts of the atmosphere, waters and soil, accumulates in living organisms and on anthropogenic objects. This work investigates organic pollutantsin BBC in relation to their spread, behavior a...
The sign change problem in quantitative structure–activity relationship (QSAR), quantitative structure–property relationship (QSPR) and related studies is the controversy related to the signs of correlation coefficients and regression coefficients of a descriptor in univariate and multivariate regressions, before and after the data split. Among 50...
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Four Quantitative Structure–Activity Relationship (QSAR) models were constructed for a set of 32 and 16 HIV-1 protease inhibitors in the training and external validation sets, respectively, using the biological activity and molecular descriptors from the literature. Two QSAR models were based on Support Vector Machines methods (SVM): Support Vector...
Four quantitative structure-activity relationships (QSAR) and quantitative structure-property relationship (QSPR) data sets were selected from the literature and used to build regression models with 75, 56, 50 and 15 training samples. The models were validated by leave-one-out crossvalidation, leave-N-out crossvalidation (LNO), external validation,...
Over hundred new a priori global/local molecular descriptors that encoded steric, topological, electronic, hydrogen bonding, compositional and hydrophobic properties were generated for 16 β-lactams, and two partial least squares regression models were constructed and cross-validated. These a priori models (Q2 > 0.80, R2 > 0.95, SEV < 0.50) are comp...
Blocking polycrystalline platinum (Pt) and boron-doped diamond (BDD) electrodes by 20 phenolic compounds was studied by means
of chronoamperometric and theoretical methods [i.e., quantitative structure-property relationships (QSPRs)] and chemometric
methods. The difference between the current densities after 15 and
of oxidation time was proposed...
The geometry of 50 substituted benzaldehydes was optimized at the semiempirical PM3 level, and various electronic and steric descriptors accounting for properties of the benzene ring, aldehyde group, and their connecting carbon-carbon bond were calculated. Quantitative structure-property relationships (QSPR) between (17)O carbonyl chemical shifts a...
This work deals with structural properties of X-ray crystal structures of DNA-intercalator complexes, deposited in the Nucleic Acid Database (NDB) (8). It is based on previous observations (3) that the DNA helix in such structures forms infinite straight or zig-zag base-paired stacks along crystallographic directions and that the average π-system p...
Multidrug resistance activities pEC50 of sensitive, resistant, and moderately resistant strains of the pathogenic fungus Penicillium digitatum against triflumizole, fenarimol, bitertanol, pyrifenox, cycloheximide, acriflavine, and 4-nitroquinoline-N-oxide were studied by principal component and hierarchical cluster analyses. Genome descriptors for...
Structures of 12 structurally unrelated agents (training set) and 19 diverse agents (prediction set) were modeled at the PM3 level and the molecular descriptors obtained were correlated with pMIC (pMIC=−log(MIC/mol/dm3) values for E. coli strains KAM32 (without VmrA efflux pump) and KAM32/pVCJ6 (with VmrA). Partial Least Squares (PLS) and Principal...
Multidrug resistance activities pECr50 of diverse strains of pathogenic fungus Penicillium digitatum against seven toxicants were studied by Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). Fungal growth data (radii, circumferences, surface areas of fungal colonies, radius differences and ratios) in absence and presence o...
Beta-(3,4-Methylenedioxybenzyl)-gamma-butyrolactone (MDBL) and (-)-hinokinin (HK) were obtained by partial synthesis and characterized by 1H NMR and computational methods (conformational analysis, molecular modeling, structural data mining and chemometrics). Three conformers were detected for MDBL and nine were found for HK. The energy differences...
The purpose of this work is to study theoretically stereoelectronic aspects of the interaction between heme and artemisinin in the transitional heme-artemisinin complex. Through semi-empirical calculations using the PM3 method, the potential energy barrier of artemisinin rotation relative to heme in the heme-artemisinin complex was studied in vacuu...
AcrAB-TolC is the most important multidrug efflux pump system of Gram-negative bacteria, responsible for their resistance to lipophilic and amphiphilic drugs. In this work, a molecular graphics study of the pump components AcrB and TolC, 16 beta-lactam antibiotics and 7 other substrates, as well as of AcrB-substrate complexes, was performed in orde...
Internet surfing for the word chemometrics in national languages and, in the Science Citation Index (SCI), searching for articles containing chemometr * were performed. The bibliometric, webometric, and country development descriptors from literature were then treated by Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). In...
Structures of 31 small molecules were modeled at HF 6-31* level and 325 atom-type descriptors of different nature, such as electronegativity, polarizability, energy, charge, density,
and steric descriptors, were calculated from molecular formula, optimized geometries, and literature data. The descriptors
were employed in PLS (partial least squares)...
Quantitative Structure-Activity Relationship (QSAR) study on 22 1H-indole-3-acetic acid derivatives with auxin activity was performed by means of Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), Partial Least Squares Regression (PLS) and Multiple Linear Regression (MLR). Molecular geometry of the auxins was optimized at MMFF...
AcrAB-TolC is the most important efflux pump system of Gram-negative bacteria, responsible for their resistance to lipophilic and amphilic drugs. In this work, HCA–PCA studies were performed to investigate the relationship between efflux activities (negative logarithm of minial inhibitor concentration, pMIC) of three strains of S. thypimurium with...
Geometries of free 1H-indole-3-acetic acid (IAA) and IAA hydrogen bond dimer were optimized at several computational levels: molecular mechanics, semiempirical methods, ab initio density functional theory with SVWN (Slater-Vosko-Wilk-Nusair) and Becke's three-parameter exchange functional and the gradient-corrected functional of Lee, Yang, and Paar...
Artemisinin derivatives with antimalarial activity against Plasmodium falciparum resistant to mefloquine are designed with the aid of Quantum Chemical and Partial Least Squares Methods. The PLS model with three principal components explaining 89.55% of total variance, Q2=0.83 and R2=0.92 was obtained for 14/5 molecules in the training/external vali...
Three hundred and nine carbon-carbon, carbon-nitrogen, and carbon-oxygen pi-bond lengths in high precision crystal structures of 31 purine and pyrimidine nucleobases were related to the Pauling pi-bond order, its analogues corrected to crystal packing effects, the numbers of non-hydrogen atoms around the bond, and the sum of atomic numbers of the b...
Molecular graphics and modeling methods illustrated the chemical background of the a priori approach from part I, and visualized steric and electronic enzyme-inhibitor relationships at qualitative and quantitative level for 34 and its derivatives. The enzyme-inhibitor electron density overlap occurs at 1.5-5.5 Angstrom cut-off distance, beyond van...
Quantitative Structure-Activity Relationship (QSAR) study of two sets of oral progestogens was carried out by using Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA) and Partial Least Squares (PLS). A priori, computed (at DFT 6-31G** level) and molecular graphics and modeling descriptors were employed. Molecular graphics and m...
A quantitative structure-activity relationship (QSAR) study on 48 peptidic HIV-1 protease inhibitors was performed. Fourteen a priori molecular descriptors were used to build QSAR models. Hierarchical cluster analysis (HCA), principal component analysis (PCA) and partial least squares (PLS) regression were employed. PLS models with 32/16 (model I)...
Quantitative Structure-Activity Relationship study on 21 oral progestogens, 19 of which are 17-alpha-acetoxyprogesterones, was performed by using Partial Least Squares. Fairly good regression models were achieved, the best being Q²=0.707, R²=0.811 with two Principal Components and four descriptors. Most of the molecular descriptors were generated f...
Two hundred and twenty-three aromatic carbon-carbon bond lengths in high precision crystal structures containing 22 planar condensed benzenoid polycyclic aromatic hydrocarbons (PB-PAHs) were related to the Pauling pi-bond order, its analogue corrected to crystal packing effects, the number of hexagonal rings around the bond, and the numbers of carb...
Structural (X-ray and MP2(fc)/6-31G*) features of 1,4∶5,8-diepoxynaphthalenes 1 and 2 are reported. The extent of endo bending of the olefinic hydrogens is estimated from the calculated structures and compared with the X-ray data. The computed out-of-plane angles are 7.6 and 6.8° in 1 and 2, respectively. Photoelectron spectroscopic data of diepoxy...
As part of molecular recognition studies on the phytohormone indole-3-acetic acid (IAA) a series of alkylated IAAs has been examined. Phenyl-ring substitution (alkyl = methyl and ethyl) at positions 4-, 6- or 7- as well as pyrrole substitution at the 2- site resulted in the six compounds which are analyzed: 2-Me-IAA, 4-Me-IAA, 6-Me-IAA, 7-Me-IAA, 4...
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
Two diazapyrenes, 5,10-dimethyl-4,9-diazapyrene (1) and novel 2,7-dimethyl-4,9-diazapyrene (2) have been synthesized. Their crystal structures are reported here and are the first representatives of diazapyrenes. Crystal data: (1) monoclinic, P2(1)/c, a = 4.0246 (5), b = 15.5147 (5), c = 9.1453 (9) Å, beta = 101.23 (1) degrees, V = 560.1 (1) Å(3), Z...
Two diazapyrenes, 5,10-dimethyl-4,9-diazapyrene (1) and novel 2,7-dimethyl-4,9-diazapyrene (2) have been synthesized. Their crystal structures are reported here and are the first representatives of diazapyrenes. Crystal data: (1) monoclinic, P21/c, a = 4.0246 (5), b = 15.5147 (5), c = 9.1453 (9) Å, β = 101.23 (1)°, V = 560.1 (1) Å3, Z = 2, R = 0.04...
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...
Bond length-bond order relationships for carbon-carbon, carbon-nitrogen and carbon-oxygen bonds in benzenoid hydrocarbons, azabenzenoids and picrate-like systems are reinvestigated and discussed. The novel relationships between bond lengths and bond orders, computed by valence bond (VB) and molecular orbital (MO) methods were established using regr...
Surface spherical harmonics and their squares occur in quantum chemistry as angular wavefunctions and angular probability densities, respectively. These functions can be found in a large variety of physico-chemical problems dealing with spherical symmetry or spherical surfaces. Thus there is a great need for exact graphical representation of the ha...
The complexes formed between Cu(II), Pb(II), Cd(II), Zn(II) and Hg(II) salts and some aromatic humic-like complexants in the chromatographic process, simulating natural conditions, were investigated by X-ray powder diffraction and IR-spectroscopic analyses; most of the complexes formed were identified.
The crystal structures of the title compounds are studied in order to investigate the role of novel fluoroionophores in complexation of sodium and potassium. In the potassium complex seven coordination, including the picrate ligand, is encountered. An additional coordination site is via the phenanthridine nitrogen at 3.252 (2) Angstrom (second coor...
The cyclo-bis-intercaland type of receptor molecules based on phenanthridinium units have been synthesized and their spectroscopic (NMR, electronic absorption and fluorescence) properties studied. X-ray structures of two macrocyclic bis-phenanthridine precursors of cyclo-bis-intercalands have been determined.
The title compound, a novel monocyclic beta-lactam, was prepared and chemically characterized by IR and H-1 NMR spectroscopy and X-ray structure analysis. C9H14N2O6S.H2O exists as a zwitterion crystallized with a water molecule. The four-membered lactam ring is slightly puckered, the ammonio and sulfonate groups are cis, and the aliphatic substitue...
The structure and properties of 2-(3-pyridylmethyliminomethyl)phenol have been determined by X-ray crystallography, NMR, UV and IR spectroscopy and compared with the characteristics of the Schiff bases derived from salicylaldehyde and aminopyridines. Crystal data: C13H12N2O, Mr = 212.250, monoclinic, space group P21/n, a = 10.49(1) Å, b = 9.002(4)...
Novel fluoroionophores bearing two (1) and one (2) fluorophoric 6-phenanthridinyl units attached by a short methylene spacer onto nitrogen atoms of 7,16-diaza- and aza-18-crown-6 rings have been prepared in high yields. The fluoroionophores exhibited the ability to signal binding of certain metal cations through the specific complexation induced sh...
S-α-Methyl-[1-(substituted-phenyl)-2-(2′-pyrido)-1-ethylidene]benzylamines 15–21 and their Rh(I) complexes 22–28 are prepared and their chiroptical and conformational properties are studied. Free ligands are present as enamines in the solution and in the solid state, but are bound to Rh(I) in the imine form. The CD spectra confirm that complexation...