Paradigmaváltások a kémia történetében

Mind a vegyészettel kapcsolatos ismeretek és eljárások több évezredes, mind pedig a modern kémia kb. két és fél évszázados története alatt számos eszköz, kísérleti módszer, fogalmi megközelítés, illetve tudományos elmélet többszöri paradigmaváltáson keresztül érte el a mai fejlettségi állapotát. Az új paradigma befogadását részben a hasznosságának, általánosíthatóságának az objektív belátása, részben persze a Max Planck-nak tulajdonított - nem pusztán szellemes, de sokszor helytálló - megállapítás indokolja („az igazság sosem diadalmaskodik, csak kihalnak az ellenfelei”). A kémiai tudomány területéről, példának okáért, az alábbi fogalmak, illetve a hozzájuk kapcsolódó megközelítések, elméletek említhetők, amelyek akár sorozatos paradigmaváltásokon estek át, mire a rájuk vonatkozó mai egységes álláspont kialakult: · a hő természete és eredete; a hőanyagelmélet; a hő kinetikus elmélete, a hő és az energia kapcsolata, az energiamegmaradás törvénye; · az égés jelensége és folyamata; a „flogisztonelmélet”; az égés Lavoisierféle értelmezése; az égések és lángok kinetikája és mechanizmusa; · sav-bázis fogalmak, és a kapcsolódó kísérleti tapasztalatok; a sav-bázis elméletek és korlátaik; · a kémiai kötés oka, tulajdonsága, kialakulása; kötéselméletek; a kvantummechanika szerepe a kémiai kötés értelmezésében. Az előadás során a felsorolt témákon keresztül fogunk betekintést nyerni a kémiatörténet paradigmaváltást hozó „nagy pillanataiba”

2-es típusú diabetes mellitus, inzulinrezisztencia és májrák idült hepatitis C-fertőzésben. Északkelet-magyarországi adatok = Type 2 diabetes mellitus, insulin resistance and hepatocellular carcinoma in chronic hepatitis C patients Data from Northeastern Hungary

Absztrakt: Bevezetés: Az idült hepatitis C-vírus (HCV)-fertőzés gyakori szövődményei a májzsugor (20–25%) és a májrák (1,5–3%), valamint az inzulinrezisztencia (30–40%) és a 2-es típusú diabetes mellitus (25–30%); az utóbbiakról kevés magyar adat érhető el. Célkitűzés: A kórképek gyakoriságát, az interferonalapú terápiával kapcsolatos metabolikus változásokat és a virológiai válaszkészséget értékeltük magyar betegekben, akiket tartósan követtünk a májrák korai felismerésére. Módszer: Vizsgálatunkban 150 HCV-beteg (átlagéletkor: 48,55 ± 8,55 év, férfi/nő: 45/55%) kezelés előtti, alatti és utáni adatait elemeztük, majd 5 éves követést végeztünk (2012–2017). Eredmények: A vizsgálatba bevont betegek 35,3%-a inzulinrezisztensnek, míg 27,3%-a diabetesesnek bizonyult; e két vizsgálati alcsoportban a vérminták levételének napján a kiindulásihoz képest szignifikánsan csökkent éhgyomri vércukorértékek mutatkoztak a kezelést követően fél évvel (5,47 ± 0,66 vs. 5,08 ± 0,60, p<0,001; 7,90 ± 2,67 vs. 7,04 ± 2,75, p = 0,006). Észlelésünk független volt az antivirális kezelés sikerétől, mely a cukorbetegekben jelentősen kisebbnek bizonyult az inzulinszenzitív és az inzulinrezisztens csoportétól (17% vs. 46% és 40%). A tartós vírusmentesség elérésében nem volt előny az inzulinszenzitivitás. Az 5 éves követés alatt három cukorbetegben jelent meg májrák, amelyek felismerése rendszeres ultrahang-szűrővizsgálat révén történt. Következtetés: Az inzulinrezisztencia és a 2-es típusú diabetes az irodalmi adatokkal egyezően gyakori volt idült HCV-fertőzött betegeinkben. Az antivirális kezelés kedvező szénhidrátanyagcsere-változásokat eredményezett. Adataink megerősítik, hogy a korai májrák felfedezésére a májzsugorban és cukorbetegségben szenvedő HCV-betegekben is félévenként hasi ultrahangvizsgálat végzése szükséges. Orv Hetil. 2019; 160(40): 1591–1602. | Abstract: Introduction: Liver cirrhosis (20–25%), hepatocellular carcinoma (1.5–3%), insulin resistance (30–40%) and type 2 diabetes (25–30%) are common complications in patients with chronic hepatitis C virus (HCV) infection; however, data are missing from Hungary. Aim: To determine the prevalence of diabetes and insulin resistance in Hungarian HCV patients; to evaluate treatment-induced metabolic changes in relation to diabetes/insulin resistance and virological response and to perform a sustained follow-up for hepatocellular carcinoma detection. Method: We enrolled 150 Hungarian HCV genotype 1 patients (mean age: 48.55 ± 8.55 years, male/female ratio: 45/55%) from 2007–2012. We analysed their baseline, week 12, and end of therapeutic follow-up (24 weeks after interferon-based therapy completion) laboratory data. We performed a 5-year follow-up (2012–2017). Results: The prevalence of insulin sensitivity, insulin resistance and diabetes was 37.4%, 35.3% and 27.3%, respectively. Insulin resistant and diabetic patients showed a decrease in fasting glucose from baseline to end of follow-up (5.47 ± 0.66 vs. 5.08 ± 0.60, p<0.001; 7.90 ± 2.67 vs. 7.04 ± 2.75, p = 0.006), as did both the sustained responder and non-responder groups. Treatment efficacy rate was poor in diabetic vs. insulin sensitive and insulin resistant groups (17% vs. 46% and 40%); insulin sensitivity was not a predictor of virological response. Three participants with diabetes were diagnosed with hepatocellular carcinoma during follow-up by regular ultrasound examinations. Conclusion: Hungarian HCV patients showed high prevalence of diabetes and insulin resistance, though antiviral therapy caused favourable changes in their carbohydrate metabolism. Antiviral therapy was less effective in diabetic patients. Follow-up ultrasound examinations are required for hepatocellular carcinoma in HCV patients, especially those with diabetes. Orv Hetil. 2019; 160(40): 1591–1602

Synthesis, physico-chemical characterization and bacteriostatic study of Pt complexes with substituted amine ligands

Three complexes of general formula PtCl2R2 were synthesized, where R is the amine ligand with aromatic substituents. Coordination compounds [Pt(an)2Cl2] (1), [Pt(pa)2Cl2] (2) and [Pt(aph)2Cl2] (3), where an = 2-aminonaphthalene, pa = 2-aminopyrimidine, aph = 4-anilinophenol, were characterized by on-line coupled TG/DTA-MS, powder XRD and spectroscopic techniques (FTIR, ESI–MS and NMR), and tested against selected Gram(+) and Gram(–) bacteria. The thermal data show that all three compounds contain lattice or absorbed water, and the stability of the anhydrous compounds in nitrogen decreases in the order 2 > 1 > 3. Above 200 °C, the complexes loose characteristic fragments of their ligands. The spectroscopic data are in accordance with the thermal properties of the samples and prove their composition. The compounds are more effective inhibitors of Gram(+) than Gram(−) bacteria. © 2016 Akadémiai Kiadó, Budapest, Hungar

Total synthesis of isotopically enriched Si-29 silica NPs as potential spikes for isotope dilution quantification of natural silica NPs

A new method was developed for the preparation of highly monodisperse isotopically enriched Si-29 silica nanoparticles (29Si-silica NPs) with the purpose of using them as spikes for isotope dilution mass spectrometry (IDMS) quantification of silica NPs with natural isotopic distribution. Si-29 tetraethyl orthosilicate (29Si-TEOS), the silica precursor was prepared in two steps starting from elementary silicon-29 pellets. In the first step Si-29 silicon tetrachloride (29SiCl4) was prepared by heating elementary silicon-29 in chlorine gas stream. By using a multistep cooling system and the dilution of the volatile and moisture-sensitive 29SiCl4 in carbon tetrachloride as inert medium we managed to reduce product loss caused by evaporation. 29Si-TEOS was obtained by treating 29SiCl4 with absolute ethanol. Structural characterisation of 29Si-TEOS was performed by using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. For the NP preparation, a basic amino acid catalysis route was used and the resulting NPs were analysed using transmission electron microscopy (TEM), small angle X-ray scattering (SAXS), dynamic light scattering (DLS) and zeta potential measurements. Finally, the feasibility of using enriched NPs for on-line field-flow fractionation coupled with multi-angle light scattering and inductively coupled plasma mass spectrometry (FFF/MALS/ICP-MS) has been demonstrated

Novel cobalt complexes with glyoximes : synthesis, physicochemical analysis and biological study

Azomethine derivatives have several applications, especially as reagents for the determination of transition metal ions. Furthermore these ligands and their cobalt complexes were also reported to possess biological activities, such as antimicrobial, anti-tubercular, anticonvulsant, anti-inflammatory, anti-proliferative activities as well as antifungal inhibition potential [1]. Another reason for using metal-containing compounds as structural scaffolds is related to the kinetic stability of their coordination spheres in the biological environment. Metallic ions have been shown to play important role in the biological activity of different compounds in such away that, in some cases, activity is enhanced or only takes place in the presence of these ions [2]. In our research new cobalt(III) complexes were synthesized with -glyoximes, azides, amines, thiocyanate and halogens, such as [Co(Me-propyl-GlyoxH)2(N3)(amine)], [Co(Mepentyl-GlyoxH)2(N3)(amine)], [Co(Et-propyl-GlyoxH)2(N3)(amine)], [Co(Et-propylGlyoxH)2(Br)(amine)], [Co(Et-propyl-GlyoxH)2(SCN)(amine)], H[Co(Et-propylGlyoxH)2(SCN)2], [Co(phenyl-Me-GlyoxH)2(amine)2]I, [Co(Et-propyl-GlyoxH)2(amine)2]I, [Co(Et-Bu-GlyoxH)2(amine)2]I, where GlyoxH = mono deprotonated glyoxime, and the used amines: imidazole, 3-hydroxy-aniline, lepidine, 3,5-dimethyl-pyridine, di(n-butyl)-amine, diisopropyl-amine, 2-amino-pyrimidine, diphenyl-amine, 2-picoline, 3-picoline. The Co(II)- acetate salt dissolved in water and mixed with the glyoxime alcoholic solution was oxidized by air bubbling, then the corresponding diamines and the other complexing agents were added. The molecular structure of our products was investigated by IR, UV–VIS spectroscopy, mass spectrometry (MS), thermoanalytical measurements (TG-DTG-DTA), and powder XRD. The biological activity, like antimicrobial effect, was studied for a few bacteria

Considering PKI Safety Impact on Network Performance During V2X-based AD/ADAS Function Development Processes

In this research, we examine the impact of PKI on vehicle safety and thus make suggestions for further improvements to V2X-based safety application design processes. In the first step, we introduce the novel methodological background of characterizing the safety impact of the network performance metrics on the V2X-based automotive applications. Following this, we investigated two cases: with and without Public Key Infrastructure (PKI) authorization, to identify the potential safety effect if the V2X device is unprepared for the additional computational overhead caused by the authentication framework-related processes. Based on our results, we can identify the operational domain of a specific V2X-based application that can be used safely

Novel platinum complexes with schiff bases and α-Dioximes, their physico-chemical and biological study

In our research project we prepared the following platinum(II) complexes with Schiff bases and -dioximes, such as [Pt(ketone)2A(L2)], (ketone: 2-heptanone, 2-octanone, 3-octanone; A: hydrazine, phenylhydrazine, o-phenylene-diamine; L: 1-naphthylamine, 2-aminopyrimidine, 2-methylimidazole, 2-amino-4-methylpyridine) and [Pt(DioxH)2L2], (DioxH2: methyl-phenyl-dioxime, butyl-methyl-dioxime; L: 1-naphthylamine, 2-methylimidazole, 2-amino-4-methylpyridine, lepidine, 2-methylpyridine, m-toluidine, dicyclohexylamine, 4-isopropylamine, cyclohexylamine), by the reaction of PtCl2 in suitable solvent. After a short bibliographical survey, involving the classification and evolution of platinum complexes with possible applications, we analyzed their physico-chemical properties using FTIR, Raman, NMR, UV-VIS spectroscopy, powder X-ray diffraction (XRD), mass spectrometry, thermal analysis (TG, DTG, DTA) and SEM. We also studied the antibacterial effect of complexes on different strains of bacteria. This class of compounds has relevance in biochemistry, some of them are antibacterial agents and potential anti-tumor drugs

Novel iron complexes with glyoximes, schiff bases and boric acid derivatives : synthesis, physico-chemical analysis and biological study

Iron(II) clathrochelate complexes obtained with glyoximes are macrobicyclic ligand systems, which completely encapsulate the metal ion, and are formed under mild conditions with high yields [1]. In particular, the riblike-functionalized clatrochelates both with the inherent and with the terminal closo-borate substituents synthesized recently have been proposed as new radiopharmaceuticals for boron neutron capture therapy of cancer [2]. In our research work new iron(II) complexes were synthesized with -glyoximes, boric acid derivatives, amines, Schiff bases, such as [Fe(Me-Pr-Glyox)3(BO–Et)2], [Fe(Et-BuGlyox)3(BO–R)2] (R = methyl, propyl, butyl), [Fe(phenyl-Me-GlyoxH)2(amine)2], [Fe(Et-BuGlyoxH)2(amine)2], [Fe(2-heptanone)2(en)(amine)2], where GlyoxH, Glyox = mono- or bideprotonated glyoxime, en = ethylenediamine and the used amines: dibutylamine, 3-picoline, 4-aminopyridine, 6-amino-3-picoline, 3-amino-1-propanol, imidazole, 2-aminopyrimidine, 3- methylpiperidine, 3-amino-1H-1,2,4-triazole. For preparation ironII -sulfate was dissolved in water and mixed with alcoholic solution of the glyoxime, then the corresponding amines and the other complexing agents were added. The mixture so obtained was refluxed under inert atmosphere. The molecular structures of our products were studied by IR, Mössbauer and UV–VIS spectroscopies, mass spectrometry (MS) and thermoanalytical measurements (TG-DTG-DTA). The biological activity, like antimicrobial effect, was studied for a few bacteria