Обучение по природни науки и върхови технологии

2019/4, стр. 505 - 514

SPECTRAL, BIOLOGICAL, MAGNETIC AND CONDUCTANCE STUDIES ON THE COORDINATION COMPOUNDS OFANEWLY SYNTHESIZED THIAZOLIDIN-4-ONE

Dinesh Kumar
Department of Chemistry
Indira Gandhi National College
Ladwa Kurukshetra
136132 Haryana India
Amit Kumar
E-mail: amitvash76@gmail.com
Department of Chemistry
Indira Gandhi National College
Ladwa Kurukshetra
136132 Haryana India

Резюме: A dry benzene solution of the Schiff base, N-(2-hydroxyphenyl)3‘-carboxy-2‘-hydroxybenzylideneimine upon reacting with mercaptoacetic acid undergoes cyclization and forms N-(2-hydroxyphenyl)-C-(3‘-carboxy-2‘-hydroxyphenyl) thiazolidin-4-one, LH3(I). A MeOH solution of I reacts with CoII and CdII ions and forms the monomeric coordination compounds, [Co(LH)(MeOH) 3](II) and [Cd(LH)(MeOH)](III). The coordination compounds have been characterized on the basis of elemental analyses, molar conductance, molecular weight, spectral (IR, reflectance, NMR) studies and magnetic susceptibility measurements. I behaves as a dibasic tridentate OOS donor ligand in these compounds. The compounds are non-electrolytes (LM = 5.1-7.8 mho cm2 mol-1) in DMF. A tetrahedral structure for III and an octahedral structure for II are suggested. The ligand (I) and its coordination compounds shows antibacterial and antifungual activities towards bacteria, E. Coli. (Gram Negative) and S. Aureus (Gram Positive) as well as towards fungus, Candida Albicans. Keywords: thiazolidin-4-one, coordination compounds, magnetic susceptibility, magnetically dilute, strong field and covalent character

Ключови думи: spectral; biological; magnetic and conductance studies; newly synthesized thiazolidin-4-one

Introduction

Thiazolidin-4-ones belong to an important group of heterocyclic compounds with carbonyl group at fourth position. These containing S and N in five member ring obtained by cyclocondensation of imines with mercaptoacetic acid. These are important class of heterocyclic compounds owing to their versatile pharmacological and industrial importance (Gashaw et al., 2013).

They have been studied extensively because of their ready accessibility, diversed chemical reactivity and broad spectrum of biological activities (Patel et al., 2011). The presence of a thiazolidinone ring in penicillin and related derivatives was the first recognition of its occurrence in nature (Pulici & Quartieri, 2005).

Thiazolidin-4-ones are also known to exhibit antibacterial (Sawale et al., 2012), antimicrobial (Ahirwar & Shrivastava, 2011), antifungal (Bhatt et al., 1994), antitubercular (Myangar et al., 2012) and antioxidant (Kato et al., 1999) activities. A perusal of the literature reveals that much has been reported on the syntheses and characterization (Belbehani & Ibrahim, 2012) of a variety of thiazolidin-4-ones, but little is known about their coordination compounds (Kumar et al., 2013a). Many drugs possess modified pharmacological properties in the form of the metal complexes (Anacona & Estacio, 2006). These facts prompted us to explore the ligational behavior of a newly synthesized thiazolidin-4-one, \(\mathrm{LH}_{3}(\mathbf{I})\) towards \(\mathrm{Co}^{\mathrm{II}}\) and \(\mathrm{Cd}^{\text {II }}\) ions.

OCOHOHCHNHOHOHOHCSHOCHONHCCO[Schi base]

Experimental

Materials

2-Aminophenol [Loba-Chemie (Mumbai)], mercaptoacetic acid, dry benzene, sodium bicarbonate [Ranbaxy], cadmium(II) acetate dihydrate [Sarabhai], cobalt(II) acetate tetrahydrate [BDH] were used as received for the syntheses. 3-Aldehydo-2-hydroxybenzoic acid was synthesized by following the reported procedure (Kumar et al., 2010).

Analyses and physical measurements

The organic skeleton of the respective coordination compounds was decomposed by the slow heating of \(\sim 0.1 \mathrm{~g}\) of the latter, with conc. \(\mathrm{HNO}_{3}\). The residue was dissolved in minimum amount of conc. HCl and the corresponding metal ions were estimated as follows: The Co(II) and Cd (II) contents in the respective coordination compounds were estimated by the complexometric titration method against standardized EDTA solution using xylenol orange as an indicator. The \(\mathrm{C}, \mathrm{H}\) and N contents of \(\mathrm{LH}_{3}\) and its coordination compounds were determined by CHN Eager analyzer model-300. The S contents were estimated gravimetrically as \(\mathrm{BaSO}_{4}\). The molecular weight measurements were carried out by the Rast method using diphenyl as the solvent (Mann & Saunders, 1961). The molar conductances \(\left(\mathrm{L}_{\mathrm{M}}\right)\) of the coordination compounds were measured in DMF with the help of a Toshniwal conductivity bridge (CL01-02A) and a dip type cell calibrated with KCl solutions. The IR spectra were recorded in KBr pellets (\(4000-400 \mathrm{~cm}^{-1}\) ) on a Beckman-20 spectrophotometer. The reflectance spectra were recorded on a Beckmann DU spectrophotometer attached with a reflectance arrangement. The magnetic susceptibility measurements were carried out at room temperature, using \(\mathrm{Hg}\left[\mathrm{Co}(\mathrm{NCS})_{4}\right]\) as the standard (Dutta & Syamal, 1993). The diamagnetic corrections were computed using Pascal’s constants. The magnetic susceptibilities were corrected for temperature independent paramagnetism term (TIP) (Dutta & Syamal, 1993) using value of 200 \({ }^{\prime} 10^{-6} \mathrm{cgs}\) units for Co (II) ions.

Synthesis of the Schiff base

A MeOH solution (30 mL) of 2-aminophenol (\(1.09 \mathrm{~g}, 10 \mathrm{mmol}\) ) was added to a MeOH solution \((30 \mathrm{~mL})\) of 3-aldehydo-2-hydroxybenzoic acid \((1.66 \mathrm{~g}\), 10 mmol) and the mixture was refluxed for \(2 h\). The precipitates formed were suction filtered, washed with MeOH and dried in vacuo at room temperature over silica gel for \(24 h\). Yield \(=87 \%\). The elemental analyses of the compound gave the satisfactory results.

Synthesis of \(\mathrm{LH}_{3}(\mathbf{I})\)

A dry benzene solution of the Schiff base (\(2.57 \mathrm{~g}, 10 \mathrm{mmol}\) ) and mercaptoacetic acid \((0.92 \mathrm{~g}, 10 \mathrm{mmol})\) were refluxed for \(12 h\) on a water bath. The mixture was cooled to room temperature and then was washed with \(10 \%\) sodium bicarbonate solution. The benzene layer was separated using a separating funnel. The partial evaporation of the benzene layer gave a solid product, which was filtered, washed with and recrystallized from petroleum ether. Yield \(=\) \(25 \%\). Anal: (I, \(\mathrm{C}_{16} \mathrm{H}_{13} \mathrm{NO}_{5} \mathrm{~S}\) ) (obsd: C C, \(57.80 \% ; \mathrm{H}, 3.75 \% ; \mathrm{N}, 4.10 \% ; \mathrm{S}, 9.50 \%\). calc.: C, \(58.01 \% ; \mathrm{H}, 3.93 \% ; \mathrm{N}, 4.23 \% ; \mathrm{S}, 9.67 \%\) ); IR bands (KBr): \(2860 \mathrm{~cm}^{-1}\) \([v(\mathrm{O}-\mathrm{H})\) (intramolecular H-bonding) \(], 1700 \mathrm{~cm}^{-1}[v(\mathrm{C}==\mathrm{O})\) (thiazolidinone ring) \(], 1670 \mathrm{~cm}^{-1}\left[v(\mathrm{C}==\mathrm{O})\right.\) (carboxylic)], \(1575 \mathrm{~cm}^{-1}[v(\mathrm{C}-\mathrm{N})\) (thiazolidinone ring) \(], 1525 \mathrm{~cm}^{-1}[v(\mathrm{C}-\mathrm{O})\) (phenolic) \(]\) and \(835 \mathrm{~cm}^{-1}[v(\mathrm{C}-\mathrm{S})\) (thiazolidinone ring)].

Syntheses of coordination compounds of \(\mathbf{I}\)

A MeOH solution (\(30-50 \mathrm{~mL}\) ) of the appropriate metal salt (10 mmol) was added to a MeOH solution (50 mL) of \(\mathbf{I}(3.31 \mathrm{~g}, 10 \mathrm{mmol})\) and the mixture was then refluxed for \(3-4 h\). The solid products formed were suction filtered, washed with and recrystallized from MeOH and were then dried as mentioned above. Yield \(=\) \(50-80 \%\).

Results and discussion

The nucleophilic addition reaction between 3-aldehydo-2-hydroxybenzoic acid and 2-aminopohenol followed by the elimination of one water molecule results in the formation of the Schiff base, N-(2-hydroxyphenyl)-3‘-carboxy-2‘-hydroxybenzylideneimine. A dry benzene solution of the above Schiff base reacts with mercaptoacetic acid and forms N-(2-hydroxyphenyl)-C-(3‘-carboxy-26-hydroxyphenyl)thiazolidin-4-one, \(\mathrm{LH}_{3}(\mathbf{I})\). The reaction of \(\mathbf{I}\) with appropriate metal ions in 1:1 molar ratio in MeOH produces the coordination compounds, \(\left[\mathrm{Co}(\mathrm{LH})(\mathrm{MeOH})_{3}\right]\) and \([\mathrm{Cd}(\mathrm{LH})(\mathrm{MeOH})]\). The formations of \(\mathbf{I}\) from the Schiff base and the coordination compounds of the latter take place according to the Schemes I and II.

\[ \text { Schiff base } \xrightarrow[\text { dry benzene }]{\mathrm{HS}-\mathrm{CH}_{2} \mathrm{COOH}} \mathbf{I} \] Scheme 1. Preparative scheme of \(\mathrm{LH}_{3}\) (I)

\[ \begin{aligned} & \mathrm{LH}_{3}+\mathrm{Co}(\mathrm{OAc})_{2} \cdot 4 \mathrm{H}_{2} \mathrm{O} \xrightarrow[\text { Reflux }]{\mathrm{MeOH}}\left[\mathrm{Co}(\mathrm{LH})(\mathrm{MeOH})_{3}\right]+2 \mathrm{CH}_{3} \mathrm{COOH}+4 \mathrm{H}_{2} \mathrm{O} \\ & \mathrm{LH}_{3}+\mathrm{Cd}(\mathrm{OAc})_{2} \cdot 2 \mathrm{H}_{2} \mathrm{O} \xrightarrow[\text { Reflux }]{\text { MeOH }}[\mathrm{Cd}(\mathrm{LH})(\mathrm{MeOH})]+2 \mathrm{CH}_{3} \mathrm{COOH}+2 \mathrm{H}_{2} \mathrm{O} \end{aligned} \] Scheme 2. Preparative scheme of coordination compounds of \(\mathrm{LH}_{3}\) (I)

The coordination compounds are stable at room temperature. They are insoluble in \(\mathrm{H}_{2} \mathrm{O}\), partially soluble in MeOH, EtOH and completely soluble in DMSO and DMF. Their molar conductance measurements (\(\mathrm{L}_{\mathrm{M}}=5.1-7.8 \mathrm{mho} \mathrm{cm}^{2} \mathrm{~mol}^{-1}\) ) in DMF indicate their non-electrolytic nature. The analytical data of \(\mathbf{I}\) and its coordination compounds are presented in Table 1.

Table 1. Analytical, molar conductance (\(\Lambda_{\mathrm{M}}\) ) and molecular weight data of \(\mathrm{LH}_{3}\) [I] and its coordination compounds

CompoundMol. FormulaΛM(mhocm2mol-1) Mol. wtobsd(calcd) obsd(calcd)%MCHNSLH3C16H13NO5S331a(331.0) 57.80(58.01) 3.75(3.93) 4.10(4.23) 9.50(9.67) [Co(LH)(MeOH) 3] CoC19H23NO8S5.1497.8b(483.9) 12.34(12.17) 46.90(47.12) 4.82(4.75) 2.83(2.89) 6.50(6.61) [Cd(LH)(MeOH)] CdC17H15NO6S7.8497.3b(473.4) 23.50(23.74) 43.26(43.09) 3.00(3.17) 2.70(2.96) 6.50(6.76)

Abbreviations: \({ }^{a}\) Mass spectral data, \({ }^{b}\) Rast method data

Infrared spectral studies

The infrared spectra of the Schiff base, \(\mathbf{I}\) and the coordination compounds of the latter were recorded in KBr and the prominent peaks (in \(\mathrm{cm}^{-1}\) ) are shown in Table 2. The Schiff base exhibits the \(v(\mathrm{C}==\mathrm{N})\) (azomethine) stretch at \(1630 \mathrm{~cm}^{-1}\). This band disappears in \(\mathbf{I}\) and a new band due to the \(v(\mathrm{C}-\mathrm{N})\) (thiazolidinone ring) stretch (Shrivastava et al., 2012) appears at \(1575 \mathrm{~cm}^{-1}\) indicating the conversion of the Schiff base into \(\mathbf{I}\). The formation of \(\mathbf{I}\) is further supported by the appearance of a new band at \(835 \mathrm{~cm}^{-1}\) due to the \(v(\mathrm{C}-\mathrm{S})\) (thiazolidinone ring) stretch (Kumar & Kumar, 2012). This band shows a negative shift by \(20-40 \mathrm{~cm}^{-1}\) in the coordination compounds indicating the involvement of the S atom of the thiazolidinone moiety towards coordination (Kumar et al., 2013b). The \(\nu(\mathrm{C}==\mathrm{O})\) (thiazolidinone ring) stretch (Parekh et al., 2004) of \(\mathbf{I}\) occurs at \(1700 \mathrm{~cm}^{-1}\). This band remains unchanged in the coordination compounds indicating the non-involvement of O atom towards the coordination. The strong band due to the intramolecular H-bonded OH group of phenolic and/or carboxylic acid moieties (Bahad et al., 2000) occurring at \(2860 \mathrm{~cm}^{-1}\) disappears in the coordination compounds indicating the breakdown of H-bonding and subsequent deprotonation of the OH group followed by the involvement of phenolic and carboxylic acid O atoms towards coordination. and the The decrease presence of \(\nu v(\mathrm{C}-\mathrm{O})(\mathrm{MeOH})\) of a broad band atstretch \(\sim 3400 \mathrm{~cm}^{-1}\) from \(1034 \mathrm{~cm}^{-1}\) due to \(\nu v(\mathrm{O}-\mathrm{H})(\mathrm{MeOH})\) to lower energy by \(44-58 \mathrm{~cm}^{-1}\) in the coordination compounds indicate the involvement of the O atom of MeOH towards coordination (Kumar et al., 2013b). The appearance of two new bands between \(1558-1570 \mathrm{~cm}^{-1}, v_{\text {as }}(\mathrm{COO})\) and 1345-1356 \(\mathrm{cm}^{-1}, v_{\mathrm{s}}(\mathrm{COO})\) s stretches indicate the presence of the coordinated carboxylato group in the coordination compounds. The energy difference (\(\Delta v=213-214\) \(\mathrm{cm}^{-1}\) ) between these stretches is \( \gt 210 \mathrm{~cm}^{-1}\) and it indicates the monodentate nature of the carboxylato moiety (Anacona & Toledo, 2001). The \(v(\mathrm{C}-\mathrm{O})\) \(\phi\) stretch (Kumar et al., 2013b) of \(\mathbf{I}\) occurs at \(1525 \mathrm{~cm}^{-1}\). This band shifts to higher energy by \(7-10 \mathrm{~cm}^{-1}\) in the coordination compounds indicating the involvement of phenolic O atom of either 3-aldehydo-2-hydroxybenzoic acid or 2-aminopohenol moieties towards coordination. On the basis of steric grounds, we suggest the non-involvement of phenolic (2-aminophenol moiety) O atom towards coordination.

Table 2. IR, reflectance spectral data (\(\mathrm{cm}^{-1}\) ) and magnetic moments of coordination compounds of \(\mathrm{LH}_{3}[\mathrm{I}]\)

Compoundνas(COO) νs(COO) ν(C–O) (phenolic) Ν(C–S) ν(C–O) (MeOH) nmaxMag. moment(B. M.) LH31525835Diamagnetic
[Co(LH)(MeOH) 3] 1570135615357959769150, 12950, 191004.71[Cd(LH)(MeOH)] 155813451532815990Diamagnetic

NMR spectral studies

The NMR spectra of \(\mathbf{I}\) and \([\operatorname{Cd}(\mathrm{LH})(\mathrm{MeOH})]\) were recorded in DMSO-\(d_{6}\). The chemical shifts ( \(\delta\) ) are expressed in ppm downfield from TMS. The prominent resonance signals of these compounds were compared with the reported peaks (Nag et al., 2005). I exhibits a singlet at \(\delta 17.5 \mathrm{ppm}\) due to the carboxylic proton, a sharp singlet at \(\delta 13.61 \mathrm{ppm}\) due to phenolic proton, multiplets between \(\delta 7.36-7.71 \mathrm{ppm}\) due to the aromatic protons. The absence of the signal at \(\delta 17.5 \mathrm{ppm}\) due to the COOH proton in \([\mathrm{Cd}(\mathrm{LH})\) \((\mathrm{MeOH})]\) indicates the deprotonation of the COOH group, followed by the involvement of its O atom in coordination. The absence of the resonance signal at \(\delta 13.61 \mathrm{ppm}\) due to the phenolic proton in \([\mathrm{Cd}(\mathrm{LH})(\mathrm{MeOH})]\) indicates the deprotonation of the phenolic OH group followed by its involvement in coordination (Kumar et al., 2015).

Reflectance spectral studies

The presence of three bands at 9150 12950 and \(19100 \mathrm{~cm}^{-1}\) due to the \({ }^{4} T_{1 \mathrm{~g}}(F) \rightarrow{ }^{4} T_{2 \mathrm{~g}}\left(v_{1}\right),{ }^{4} T_{1 \mathrm{~g}}(F) \rightarrow{ }^{4} A_{2 \mathrm{~g}}\left(v_{2}\right)\) and \({ }^{4} T_{1 \mathrm{~g}}(F) \rightarrow{ }^{4} T_{1 \mathrm{~g}}\left(v_{3}\right)\) transitions, respectively suggests an octahedral arrangement of \(\mathbf{I}\) around \(\mathrm{Co}^{\mathrm{II}}\) ions in [Co(LH) \(\left.(\mathrm{MeOH})_{3}\right]\) (Lever, 1984). The \(v_{3} / v_{1}\) value in the present \(\mathrm{Co}^{\mathrm{II}}\) compound is 2.09 which lies in the usual range (2.00-2.80), reported for the majority of octahedral \(\mathrm{Co}^{\mathrm{II}}\) compounds (Lever, 1984). The spectral parameters (Huheey, 1983) are: \(10 D q=10280 \mathrm{~cm}^{-1}, B^{\prime}=738 \mathrm{~cm}^{-1}, \beta=B^{\prime} / B=0.76, \beta^{0}=24 \%\) and CFSE \(=-98.21 \mathrm{~kJ} \mathrm{~mol}^{-1}\). The reduction of Racah parameter from the free ion value of \(971 \mathrm{~cm}^{-1}\) to \(738 \mathrm{~cm}^{-1}\) and the \(\beta^{0}\) value of \(24 \%\) indicate the covalent nature of the compound and the strong field nature of the tridentate ligand (Dutta et al., 1993).

Table 3. Antimicrobial activity of \(\mathrm{LH}_{3}[\mathrm{I}]\) and its Coordination compounds (Zone of Inhibition in mm)

CompoundE.Coli(Gram negative) S. Aureus(Gram positive) Candida AlbicansLH3767[Co(LH)(MeOH) 3] 879[Cd(LH)(MeOH)] 101010

Magnetic measurements

The room temperature magnetic moment of \(\left[\mathrm{Co}(\mathrm{LH})(\mathrm{MeOH})_{3}\right]\) is 4.71 B.M. [Table 2). The value indicates its magnetically dilute high-spin nature (Cotton et al., 1999). The \([\mathrm{Cd}(\mathrm{LH})(\mathrm{MeOH})]\) is diamagnetic as expected.

Antimicrobial studies

The antimicrobial activity of ligand (I) and its complexes were tested against fungus, Candida Albicans and bacteria, E. Coli (Gram negative) and \(S\). aureus (Gram positive) by using disc diffusion method. Stock solution were prepared by dissolving compounds in DMSO. Under aseptic conditions, plain sterilised discs were soaked in solution of compounds for overnight. Test culture was spread over the plates containing Sabourads Dextrose Agar (SDA) for Candida Albicans and Mueller Hinton Agar (MHA) for E. Coli and S. aureus by using sterile swab. Inoculated plates were dried for 30 minutes and discs were placed on inoculated plates. The plates were left for 30 minutes at room temperature to allow diffusion. The plates were then incubated at \(25^{\circ} \mathrm{C}\) for 48 – 72 hours for Candida Albicans and at \(37^{\circ} \mathrm{C}\) for 24 hours for E. Coli and \(S\). aureus. After incubation, diameter of zone of inhibition were noted for each disc (Table 3).

Conclusions

Thus, on the basis of analytical, molecular weight, spectral and magnetic studies, we suggest a tetrahedral structure, III for \([\mathrm{Cd}(\mathrm{LH})(\mathrm{MeOH})]\) and an octahedral structure II for \(\left[\mathrm{Co}(\mathrm{LH})(\mathrm{MeOH})_{3}\right]\).

HOOCH2CSOHCOONCAAACo[II, A= MeOH]
OCOONCOHSCH2COHACd[III, A= MeOH]

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ХИМИЯ В МАСЛИНИТЕ

Симона Гочева, Майя Найденова

ХИМИЯ НА ЛЮТОТО

Марта Пенчева, Васка Сотирова

ХИНАП – ИЗСЛЕДВАНЕ НА СЪДЪРЖАНИЕТО НА ВИТАМИН С

Елица Нейкова, Елисавета Григорова, Майя Найденова

ХИМИЯ НA ПAРИТE

Игликa Кoлeвa, Eмилия Ивaнoвa

ВЛИЯНИЕ НА МАРИНАТИТЕ ВЪРХУ МЕСОТО

Емил Мирчев, Галя Петрова

АНАЛИЗ НА ПРИРОДНИ ВОДИ В ОБЩИНА СЛИВЕН

Никола Урумов, Анелия Иванова

ТРИНАДЕСЕТИЯТ ЕЛЕМЕНТ – СПАСИТЕЛ ИЛИ ТИХ РАЗРУШИТЕЛ?

Виктория Дечкова, Никола Велчев, Нели Иванова

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MATHEMATICAL MODELLING OF THE TRANSMISSION DYNAMICS OF PNEUMONIA AND MENINGITIS COINFECTION WITH VACCINATION

Deborah O. Daniel, Sefiu A. Onitilo, Omolade B. Benjamin, Ayoola A. Olasunkanmi

2024 година
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2023 година
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ПОДКАСТ – КОГА, АКО НЕ СЕГА?

Христо Чукурлиев

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2022 година
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METEOROLOGICAL DETERMINANTS OF COVID-19 DISEASE: A LITERATURE REVIEW

Z. Mateeva, E. Batchvarova, Z. Spasova, I. Ivanov, B. Kazakov, S. Matev, A. Simidchiev, A. Kitev

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MATHEMATICAL MODELLING OF THE TRANSMISSION MECHANISM OF PLAMODIUM FALCIPARUM

Onitilo S. A, Usman M. A., Daniel D. O. Odetunde O. S., Ogunwobi Z. O., Hammed F. A., Olubanwo O. O., Ajani A. S., Sanusi A. S., Haruna A. H.

ПОСТАНОВКА ЗА ИЗМЕРВАНЕ СКОРОСТТА НА ЗВУКА ВЪВ ВЪЗДУХ

Станислав Сланев, Хафизе Шабан, Шебнем Шабан, Анета Маринова

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MAGNETIC PROPERTIES

Sofija Blagojević, Lana Vujanović, Andreana Kovačević Ćurić

„TAP, TAP WATER“ QUANTUM TUNNELING DEMONSTRATION

Katarina Borković, Andreana Kovačević Ćurić

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КОМЕТИТЕ – I ЧАСТ

Пенчо Маркишки

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DISTANCE LEARNING: HOMEMADE COLLOIDAL SILVER

Ana Sofía Covarrubias-Montero, Jorge G. Ibanez

2021 година
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STUDY OF COMPOSITIONS FOR SELECTIVE WATER ISOLATION IN GAS WELLS

Al-Obaidi S.H., Hofmann M., Smirnov V.I., Khalaf F.H., Alwan H.H.

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POTENTIAL APPLICATIONS OF ANTIBACTERIAL COMPOUNDS IN EDIBLE COATING AS FISH PRESERVATIVE

Maulidan Firdaus, Desy Nila Rahmana, Diah Fitri Carolina, Nisrina Rahma Firdausi, Zulfaa Afiifah, Berlian Ayu Rismawati Sugiarto

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PROBLEM OF THE 8-TH EXPERIMENTAL PHYSICS OLYMPIAD, SKOPJE, 8 MAY 2021 DETERMINATION OF PLANCK CONSTANT BY LED

Todor M. Mishonov, Aleksander P. Petkov, Matteo Andreoni, Emil G. Petkov, Albert M. Varonov, Iglika M. Dimitrova, , Leonora Velkoska, Riste Popeski-Dimovski

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INVESTIGATION OF \(^{238}\)U, \(^{234}\)U AND \(^{210}\)PO CONTENT IN SELECTED BULGARIAN DRINKING WATER

Bozhidar Slavchev, Elena Geleva, Blagorodka Veleva, Hristo Protohristov, Lyuben Dobrev, Desislava Dimitrova, Vladimir Bashev, Dimitar Tonev

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DEMONSTRATION OF DAMPED ELECTRICAL OSCILLATIONS

Elena Grebenakova, Stojan Manolev

2020 година
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ДОЦ. Д-Р МАРЧЕЛ КОСТОВ КОСТОВ ЖИВОТ И ТВОРЧЕСТВО

Здравка Костова, Елена Георгиева

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JACOB’S LADDER FOR THE PHYSICS CLASSROOM

Kristijan Shishkoski, Vera Zoroska

COMPARATIVE PERFORMANCE AND DIGESTIBILITY OF NUTRIENTS IN AFSHARI AND GHEZEL RAM LAMBS

Morteza Karami, Fardis Fathizadeh, Arash Yadollahi, Mehran Aboozari, Yaser Rahimian, Reza Alipoor Filabadi

КАЛЦИЙ, ФОСФОР И ДРУГИ ФАКТОРИ ЗА КОСТНО ЗДРАВЕ

Радка Томова, Светла Асенова, Павлина Косева

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THE DAY OF THE INDUCTANCE: PROBLEMS OF THE 7\(^{TH}\) EXPERIMENTAL PHYSICS OLYMPIAD, SKOPJE, 2019

Todor M. Mishonov, Riste Popeski-Dimovski, Leonora Velkoska, Iglika M. Dimitrova, Vassil N. Gourev, Aleksander P. Petkov, Emil G. Petkov, Albert M. Varonov

MATHEMATICAL MODELING OF 2019 NOVEL CORONAVIRUS (2019 – NCOV) PANDEMIC IN NIGERIA

Sefiu A. Onitilo, Mustapha A. Usman, Olutunde S. Odetunde, Fatai A. Hammed, Zacheous O. Ogunwobi, Hammed A. Haruna, Deborah O. Daniel

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МОЛЕКУЛИТЕ НА УДОВОЛСТВИЕТО

Веселина Янкова, Снежана Демирова, Цветанка Митева, Явор Князов, Христо Желев, Димитър Георгиев, Габриела Стоянова

WATER PURIFICATION WITH LASER RADIATION

Lyubomir Lazov, Hristina Deneva, Galina Gencheva

2019 година
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LASER MICRO-PERFORATION AND FIELDS OF APPLICATION

Hristina Deneva, Lyubomir Lazov, Edmunds Teirumnieks

ПРИЛОЖНА ФОТОНИКА И АНТИОКСИДАНТНИ СВОЙСТВА НА ВИСОКООЛЕИНОВО СЛЪНЧОГЛЕДОВО МАСЛО С БИЛКОВИ ПРИМЕСИ

Кръстена Николова, Стефка Минкова, Поли Радушева, Георги Бошев, Еркан Фаридин, Нурал Джамбазов, Мариана Перифанова-Немска

ПРОЦЕСЪТ ДИФУЗИЯ – ОСНОВА НА ДИАЛИЗАТА

Берна Сабит, Джемиле Дервиш, Мая Никова, Йорданка Енева

IN VITRO EVALUATION OF THE ANTIOXIDANT PROPERTIES OF OLIVE LEAF EXTRACTS – CAPSULES VERSUS POWDER

Hugo Saint-James, Gergana Bekova, Zhanina Guberkova, Nadya Hristova-Avakumova, Liliya Atanasova, Svobodan Alexandrov, Trayko Traykov, Vera Hadjimitova

2019 − THE INTERNATIONAL YEAR OF THE PERIODIC TABLE OF CHEMICAL ELEMENTS

Maria Atanassova, Radoslav Angelov, Dessislava Gerginova, Alexander Zahariev

ТЕХНОЛОГИЯ

Б. В. Тошев

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ЗЕЛЕНА ХИМИЯ В УЧИЛИЩНАТА ЛАБОРАТОРИЯ

Александрия Генджова, Мая Тавлинова-Кирилова, Александра Камушева

ON THE GENETIC TIES BETWEEN EUROPEAN NATIONS

Jordan Tabov, Nevena Sabeva-Koleva, Georgi Gachev

CAN BRING PEOPLE TOGETHER

Nadya Kantareva-Baruh

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CHEMOMETRIC ANALYSIS OF SCHOOL LIFE IN VARNA

Radka Tomova, Petinka Galcheva, Ivajlo Trajkov, Antoaneta Hineva, Stela Grigorova, Rumyana Slavova, 6Miglena Slavova

ЦИКЛИТЕ НА КРЕБС

Ивелин Кулев

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ПРИНЦИПИТЕ НА КАРИЕРНОТО РАЗВИТИЕ НА МЛАДИЯ УЧЕН

И. Панчева, М. Недялкова, С. Кирилова, П. Петков, В. Симеонов

UTILISATION OF THE STATIC EVANS METHOD TO MEASURE MAGNETIC SUSCEPTIBILITIES OF TRANSITION METAL ACETYLACETONATE COMPLEXES AS PART OF AN UNDERGRADUATE INORGANIC LABORATORY CLASS

Anton Dobzhenetskiy, Callum A. Gater, Alexander T. M. Wilcock, Stuart K. Langley, Rachel M. Brignall, David C. Williamson, Ryan E. Mewis

A TALE OF SEVEN SCIENTISTS

Savina Kirilova

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DEVELOPMENT OF A LESSON PLAN ON THE TEACHING OF MODULE “WATER CONDUCTIVITY”

A. Thysiadou, S. Christoforidis, P. Giannakoudakis

AMPEROMETRIC NITRIC OXIDE SENSOR BASED ON MWCNT CHROMIUM(III) OXIDE NANOCOMPOSITE

Arsim Maloku, Epir Qeriqi, Liridon S. Berisha, Ilir Mazreku, Tahir Arbneshi, Kurt Kalcher

THE EFFECT OF AGING TIME ON Mg/Al HYDROTALCITES STRUCTURES

Eddy Heraldy, Triyono, Sri Juari Santosa, Karna Wijaya, Shogo Shimazu

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A CONTENT ANALYSIS OF THE RESULTS FROM THE STATE MATRICULATION EXAMINATION IN MATHEMATICS

Elena Karashtranova, Nikolay Karashtranov, Vladimir Vladimirov

SOME CONCEPTS FROM PROBABILITY AND STATISTICS AND OPPORTUNITIES TO INTEGRATE THEM IN TEACHING NATURAL SCIENCES

Elena Karashtranova, Nikolay Karashtranov, Nadezhda Borisova, Dafina Kostadinova

45. МЕЖДУНАРОДНА ОЛИМПИАДА ПО ХИМИЯ

Донка Ташева, Пенка Василева

2018 година
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ЗДРАВЕ И ОКОЛНА СРЕДА

Кадрие Шукри, Светлана Великова, Едис Мехмед

РОБОТИКА ЗА НАЧИНАЕЩИ ЕНТУСИАСТИ

Даниела Узунова, Борис Велковски, Илко Симеонов, Владислав Шабански, Димитър Колев

DESIGN AND DOCKING STUDIES OF HIS-LEU ANALOGUES AS POTENTIOAL ACE INHIBITORS

Rumen Georgiev, , Tatyana Dzimbova, Atanas Chapkanov

ELECTROCHEMICAL IMPEDANCE STUDY OF BSCCO (2212) CUPRATE CERAMIC ADDITIVE TO THE ZINC ELECTRODE IN Ni-Zn BATTERIES

A. Vasev, P. Lilov, G. Ivanova, Y. Marinov, A. Stoyanova, V. Mikli, A. Stoyanova-Ivanova

CALIBRATION OF GC/MS METHOD FOR DETERMINATION OF PHTHALATES

N. Dineva, I. Givechev, D. Tanev, D. Danalev

SONOCHEMICAL SYNTHESIS OF 4-AMINOANTIPYRINE SCHIFF BASES A ND EVALUATION OF THEIR ANTIMICROBIAL, ANTI-TYROSINASE AND DPPH SCAVENGING ACTIVITIES

Maya Chochkova, Boyka Stoykova, Iva Romanova, Petranka Petrova, Iva Tsvetkova, Hristo Najdenski, Lubomira Nikolaeva- Glomb, Nadya Nikolova, Galya Ivanova, Atanas Chapkanov, Tsenka Milkova, Martin Štícha, Ivan Nemec

ELECTROSYNTHESIS OF CADMIUM SELENIDE NANOPARTICLES WITH SIMULTANEOUS EXTRACTION INTO P-XYLENE

S. S. Fomanyuk, V. O. Smilyk, G. Y. Kolbasov, I. A. Rusetskyi, T. A. Mirnaya

БИОЛОГИЧЕН АСПЕКТ НА РЕКАНАЛИЗАЦИЯ С ВЕНОЗНА ТРОМБОЛИЗА

Мариела Филипова, Даниела Попова, Стоян Везенков

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ИМОБИЛИЗИРАНЕНАФРУКТОЗИЛТРАНСФЕРАЗА ВЪРХУКОМПОЗИТНИФИЛМИОТПОЛИМЛЕЧНА КИСЕЛИНА, КСАНТАН И ХИТОЗАН

Илия Илиев, Тонка Василева, Веселин Биволарски, Ася Виранева, Иван Бодуров, Мария Марудова, Теменужка Йовчева

ELECTRICAL IMPEDANCE SPECTROSCOPY OF GRAPHENE-E7 LIQUID-CRYSTAL NANOCOMPOSITE

Todor Vlakhov, Yordan Marinov, Georgi. Hadjichristov, Alexander Petrov

ON THE POSSIBILITY TO ANALYZE AMBIENT NOISERECORDED BYAMOBILEDEVICETHROUGH THE H/V SPECTRAL RATIO TECHNIQUE

Dragomir Gospodinov, Delko Zlatanski, Boyko Ranguelov, Alexander Kandilarov

RHEOLOGICAL PROPERTIES OF BATTER FOR GLUTEN FREE BREAD

G. Zsivanovits, D. Iserliyska, M. Momchilova, M. Marudova

ПОЛУЧАВАНЕ НА ПОЛИЕЛЕКТРОЛИТНИ КОМПЛЕКСИ ОТ ХИТОЗАН И КАЗЕИН

Антоанета Маринова, Теменужка Йовчева, Ася Виранева, Иван Бодуров, Мария Марудова

CHEMILUMINESCENT AND PHOTOMETRIC DETERMINATION OF THE ANTIOXIDANT ACTIVITY OF COCOON EXTRACTS

Y. Evtimova, V. Mihailova, L. A. Atanasova, N. G. Hristova-Avakumova, M. V. Panayotov, V. A. Hadjimitova

ИЗСЛЕДОВАТЕЛСКИ ПРАКТИКУМ

Ивелина Димитрова, Гошо Гоев, Савина Георгиева, Цвета Цанова, Любомира Иванова, Борислав Георгиев

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PARAMETRIC INTERACTION OF OPTICAL PULSES IN NONLINEAR ISOTROPIC MEDIUM

A. Dakova, V. Slavchev, D. Dakova, L. Kovachev

ДЕЙСТВИЕ НА ГАМА-ЛЪЧИТЕ ВЪРХУ ДЕЗОКСИРИБОНУКЛЕИНОВАТА КИСЕЛИНА

Мирела Вачева, Хари Стефанов, Йоана Гвоздейкова, Йорданка Енева

RADIATION PROTECTION

Natasha Ivanova, Bistra Manusheva

СРАВНИТЕЛЕН АНАЛИЗ НА СЪДЪРЖАЩИТЕ СЕ ЕСТЕСТВЕНИ РАДИОНУКЛИДИ В НЕВЕН И ЛАЙКА

Сияна Димова, Цветелина Стефанова, Йорданка Енева, Нина Архангелова

СТАБИЛНОСТ НА ЕМУЛСИИ ОТ ТИПА МАСЛО/ ВОДА С КОНЮГИРАНА ЛИНОЛОВА КИСЕЛИНА

И. Милкова-Томова, Д. Бухалова, К. Николова, И. Алексиева, И. Минчев, Г. Рунтолев

THE EFFECT OF EXTRA VIRGIN OLIVE OIL ON THE HUMAN BODY AND QUALITY CONTROL BY USING OPTICAL METHODS

Carsten Tottmann, Valentin Hedderich, Poli Radusheva, Krastena Nikolova

ИНФРАЧЕРВЕНА ТЕРМОГРАФИЯ ЗА ДИАГНОСТИКА НА ФОКАЛНА ИНФЕКЦИЯ

Рая Грозданова-Узунова, Тодор Узунов, Пепа Узунова

ЕКСПЕРИМЕНТЪТ ПО ПРИЛОЖНА ФИЗИКА И НЕГОВАТА РОЛЯ ПРИ УСВОЯВАНЕТО НА ПРАКТИКО-ПРИЛОЖНИТЕ ЗНАНИЯ ОТ КУРСАНТИТЕ И СТУДЕНТИТЕ

Николай Тодоров Долчинков, Бонка Енчева Караиванова-Долчинкова, Nikolay Dolchinkov, Bonka Karaivanova-Dolchinkova

ЕЛЕКТРИЧНИ СВОЙСТВА НА КОМПОЗИТНИ ФИЛМИ ОТ ПОЛИМЛЕЧНА КИСЕЛИНА

Ася Виранева, Иван Бодуров, Теменужка Йовчева

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PHYSICS IS AN EVER YOUNG SCIENCE

Temenuzhka Yovcheva

ТРИ ИДЕИ ЗА ЕФЕКТИВНО ОБУЧЕНИЕ

Гергана Карафезиева

МАГИЯТА НА ТВОРЧЕСТВОТО КАТО ПЪТ НА ЕСТЕСТВЕНО УЧЕНЕ В УЧЕБНИЯ ПРОЦЕС

Гергана Добрева, Жаклин Жекова, Михаела Чонос

ОБУЧЕНИЕ ПО ПРИРОДНИ НАУКИ ЧРЕЗ МИСЛОВНИ КАРТИ

Виолета Стоянова, Павлина Георгиева

ИГРА НА ДОМИНО В ЧАС ПО ФИЗИКА

Росица Кичукова, Ценка Маринова

ТЪМНАТА МАТЕРИЯ В КЛАСНАТА СТАЯ

Симона Стоянова, Анета Маринова

ПРОБЛЕМИ ПРИ ОБУЧЕНИЕТО ПО ФИЗИКА ВЪВ ВВМУ „Н. Й. ВАПЦАРОВ“

А. Христова, Г. Вангелов, И. Ташев, М. Димидов

ИЗГРАЖДАНЕ НА СИСТЕМА ОТ УЧЕБНИ ИНТЕРНЕТ РЕСУРСИ ПО ФИЗИКА И ОЦЕНКА НА ДИДАКТИЧЕСКАТА ИМ СТОЙНОСТ

Желязка Райкова, Георги Вулджев, Наталия Монева, Нели Комсалова, Айше Наби

ИНОВАЦИИ В БОРБАТА С ТУМОРНИ ОБРАЗУВАНИЯ – ЛЕЧЕНИЕ ЧРЕЗ БРАХИТЕРАПИЯ

Георги Върбанов, Радостин Михайлов, Деница Симеонова, Йорданка Енева

NATURAL RADIONUCLIDES IN DRINKING WATER

Natasha Ivanova, Bistra Manusheva

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АДАПТИРАНЕ НА ОБРАЗОВАНИЕТО ДНЕС ЗА УТРЕШНИЯ ДЕН

И. Панчева, М. Недялкова, П. Петков, Х. Александров, В. Симеонов

INTEGRATED ENGINEERING EDUCATION: THE ROLE OF ANALYSIS OF STUDENTS’ NEEDS

Veselina Kolarski, Dancho Danalev, Senia Terzieva

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ZAGREB CONNECTION INDICES OF \(\mathrm{TiO}_{2}\) NANOTUBES

Sohaib Khalid, Johan Kok, Akbar Ali, Mohsin Bashir

SYNTHESIS OF NEW 3-[(CHROMEN-3-YL) ETHYLIDENEAMINO] -PHENYL] -THIAZOLIDIN-4ONES AND THEIR ANTIBACTERIAL ACTIVITY

Ramiz Hoti, Naser Troni, Hamit Ismaili, Malesore Pllana, Musaj Pacarizi, Veprim Thaçi, Gjyle Mulliqi-Osmani

2017 година
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GEOECOLOGICAL ANALYSIS OF INDUSTRIAL CITIES: ON THE EXAMPLE OF AKTOBE AGGLOMERATION

Zharas Berdenov, Erbolat Mendibaev, Talgat Salihov, Kazhmurat Akhmedenov, Gulshat Ataeva

TECHNOGENESIS OF GEOECOLOGICAL SYSTEMS OF NORTHEN KAZAKHSTAN: PROGRESS, DEVELOPMENT AND EVOLUTION

Kulchichan Dzhanaleyeva, Gulnur Mazhitova, Altyn Zhanguzhina, Zharas Berdenov, Tursynkul Bazarbayeva, Emin Atasoy

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47-А НАЦИОНАЛНА КОНФЕРЕНЦИЯ НА УЧИТЕЛИТЕ ПО ХИМИЯ

В последните години тези традиционни за българското учителство конфе- ренции се организират от Българското дружество по химическо образование и история и философия на химията. То е асоцииран член на Съюза на химици- те в България, който пък е член на Европейската асоциация на химическите и

SYNTHESIS OF TiO 2-M (Cd, Co, Mn) AS A PHOTOCATALYST DEGRADATION OF METHYLENE BLUE DYE

Candra Purnawan, Sayekti Wahyuningsih, Dwita Nur Aisyah

EFFECT OF DIFFERENT CADMIUM CONCENTRATION ON SOME BIOCHEMICAL PARAMETERS IN ‘ISA BROWN’ HYBRID CHICKEN

Imer Haziri, Adem Rama, Fatgzim Latifi, Dorjana Beqiraj-Kalamishi, Ibrahim Mehmeti, Arben Haziri

PHYTOCHEMICAL AND <i>IN VITRO</i> ANTIOXIDANT STUDIES OF <i>PRIMULA VERIS</i> (L.) GROWING WILD IN KOSOVO

Ibrahim Rudhani, Florentina Raci, Hamide Ibrahimi, Arben Mehmeti, Ariana Kameri, Fatmir Faiku, Majlinda Daci, Sevdije Govori, Arben Haziri

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„СИМВОЛНИЯТ КАПИТАЛ“ НА БЪЛГАРСКОТО УЧИЛИЩЕ

Николай Цанков, Веска Гювийска

KINETICS OF PHOTO-ELECTRO-ASSISTED DEGRADATION OF REMAZOL RED 5B

Fitria Rahmawati, Tri Martini, Nina Iswati

ALLELOPATHIC AND IN VITRO ANTICANCER ACTIVITY OF STEVIA AND CHIA

Asya Dragoeva, Vanya Koleva, Zheni Stoyanova, Eli Zayova, Selime Ali

NOVEL HETEROARYLAMINO-CHROMEN-2-ONES AND THEIR ANTIBACTERIAL ACTIVITY

Ramiz Hoti, Naser Troni, Hamit Ismaili, Gjyle Mulliqi-Osmani, Veprim Thaçi

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OPTIMIZATION OF ENGINE OIL FORMULATION USING RESPONSE SURFACE METHODOLOGY AND GENETIC ALGORITHM: A COMPARATIVE STUDY

Behnaz Azmoon, Abolfazl Semnani, Ramin Jaberzadeh Ansari, Hamid Shakoori Langeroodi, Mahboube Shirani, Shima Ghanavati Nasab

CHEMOMETRICASSISTEDSPECTROPHOTOMETRIC ESTIMATION OF LANSOPRAZOLE AND DOMEPERIDONE IN BULK AND COMMERCIAL DOSAGE FORM

Farheen Sami, Shahnaz Majeed, Tengku Azlan Shah Tengku Mohammed, Noor Fatin Amalina Kamaruddin, Mohammad Zulhimi Atan, Syed Amir Javid Bukhari, Namra, Bushra Hasan, Mohammed Tahir Ansari

EVALUATION OF ANTIBACTERIAL ACTIVITY OF DIFFERENT SOLVENT EXTRACTS OF <i>TEUCRIUM CHAMAEDRYS</i> (L. ) GROWING WILD IN KOSOVO

Arben Haziri, Fatmir Faiku, Roze Berisha, Ibrahim Mehmeti, Sevdije Govori, Imer Haziri

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ПРИРОДОНАУЧНАТА ГРАМОТНОСТ НА УЧЕНИЦИТЕ В НАЧАЛОТО НА XXI ВЕК – В ТЪРСЕНЕ НА КОНЦЕПТУАЛНО ЕДИНСТВО

Теодора Коларова, Иса Хаджиали, Мимия Докова, Веселин Александров

COMPUTER SIMULATORS: APPLICATION FOR GRADUATES’ADAPTATION AT OIL AND GAS REFINERIES

Irena O. Dolganova, Igor M. Dolganov, Kseniya A. Vasyuchka

SYNTHESIS OF NEW [(3-NITRO-2-OXO-2H-CHROMEN4-YLAMINO) -PHENYL] -PHENYL-TRIAZOLIDIN-4-ONES AND THEIR ANTIBACTERIAL ACTIVITY

Ramiz Hoti, Hamit Ismaili, Idriz Vehapi, Naser Troni, Gjyle Mulliqi-Osmani, Veprim Thaçi

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2016 година
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THE EFFECT OF KOH AND KCL ADDITION TO THE DESTILATION OF ETHANOL-WATER MIXTURE

Khoirina Dwi Nugrahaningtyas, Fitria Rahmawati, Avrina Kumalasari

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VOLTAMMERIC SENSOR FOR NITROPHENOLS BASED ON SCREEN-PRINTED ELECTRODE MODIFIED WITH REDUCED GRAPHENE OXIDE

Arsim Maloku, Liridon S. Berisha, Granit Jashari, Eduard Andoni, Tahir Arbneshi

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ИЗСЛЕДВАНЕ НА ПРОФЕСИОНАЛНО-ПЕДАГОГИЧЕСКАТА РЕФЛЕКСИЯ НА УЧИТЕЛЯ ПО БИОЛОГИЯ (ЧАСТ ВТОРА)

Надежда Райчева, Иса Хаджиали, Наташа Цанова, Виктория Нечева

EXISTING NATURE OF SCIENCE TEACHING OF A THAI IN-SERVICE BIOLOGY TEACHER

Wimol Sumranwanich, Sitthipon Art-in, Panee Maneechom, Chokchai Yuenyong

NUTRIENT COMPOSITION OF CUCURBITA MELO GROWING IN KOSOVO

Fatmir Faiku, Arben Haziri, Fatbardh Gashi, Naser Troni

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CONTEXT-BASED CHEMISTRY LAB WORK WITH THE USE OF COMPUTER-ASSISTED LEARNING SYSTEM

N. Y. Stozhko, A. V. Tchernysheva, E.M. Podshivalova, B.I. Bortnik

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ПО ПЪТЯ ON THE ROAD

Б. В. Тошев

INTERDISCIPLINARY PROJECT FOR ENHANCING STUDENTS’ INTEREST IN CHEMISTRY

Stela Georgieva, Petar Todorov, Zlatina Genova, Petia Peneva

2015 година
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COMPLEX SYSTEMS FOR DRUG TRANSPORT ACROSS CELL MEMBRANES

Nikoleta Ivanova, Yana Tsoneva, Nina Ilkova, Anela Ivanova

SURFACE FUNCTIONALIZATION OF SILICA SOL-GEL MICROPARTICLES WITH EUROPIUM COMPLEXES

Nina Danchova, Gulay Ahmed, Michael Bredol, Stoyan Gutzov

INTERFACIAL REORGANIZATION OF MOLECULAR ASSEMBLIES USED AS DRUG DELIVERY SYSTEMS

I. Panaiotov, Tz. Ivanova, K. Balashev, N. Grozev, I. Minkov, K. Mircheva

KINETICS OF THE OSMOTIC PROCESS AND THE POLARIZATION EFFECT

Boryan P. Radoev, Ivan L. Minkov, Emil D. Manev

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Lidia Alexandrova, Michail Nedyalkov, Dimo Platikanov

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TEACHER’S ACCEPTANCE OF STUDENTS WITH DISABILITY

Daniela Dimitrova-Radojchikj, Natasha Chichevska-Jovanova

APPLICATION OF LASER INDUCED BREAKDOWN SPECTROSCOPY AS NONDESDUCTRIVE AND SAFE ANALYSIS METHOD FOR COMPOSITE SOLID PROPELLANTS

Amir Hossein Farhadian, Masoud Kavosh Tehrani, Mohammad Hossein Keshavarz, Seyyed Mohamad Reza Darbany, Mehran Karimi, Amir Hossein Rezayi

THE EFFECT OF DIOCTYLPHTHALATE ON INITIAL PROPERTIES AND FIELD PERFORMANCE OF SOME SEMISYNTHETIC ENGINE OILS

Azadeh Ghasemizadeh, Abolfazl Semnani, Hamid Shakoori Langeroodi, Alireza Nezamzade Ejhieh

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Fatmir Faiku, Arben Haziri, Fatbardh Gashi, Naser Troni

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БЛАГОДАРЯ ВИ!

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Радка Томова, Елена Бояджиева, Миглена Славова, Мариан Николов

BILINGUAL COURSE IN BIOTECHNOLOGY: INTERDISCIPLINARY MODEL1)

V. Kolarski, D. Marinkova, R. Raykova, D. Danalev, S. Terzieva

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Елица Чорбаджийска, Величка Димитрова, Магдалена Шекерлийска, Галина Бальова, Методийка Ангелова

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Здравка Костова

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SYNTHESIS OF FLUORINATED HYDROXYCINNAMOYL DERIVATIVES OF ANTI-INFLUENZA DRUGS AND THEIR BIOLOGICAL ACTIVITY

Boyka Stoykova, Maya Chochkova, Galya Ivanova, Luchia Mukova, Nadya Nikolova, Lubomira Nikolaeva-Glomb, Pavel Vojtíšek, Tsenka Milkova, Martin Štícha, David Havlíček

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NEW DERIVATIVES OF OSELTAMIVIR WITH BILE ACIDS

Kiril Chuchkov, Silvia Nakova, Lucia Mukova, Angel Galabov, Ivanka Stankova

MONOHYDROXY FLAVONES. PART III: THE MULLIKEN ANALYSIS

Maria Vakarelska-Popovska, Zhivko Velkov

LEU-ARG ANALOGUES: SYNTHESIS, IR CHARACTERIZATION AND DOCKING STUDIES

Tatyana Dzimbova, Atanas Chapkanov, Tamara Pajpanova

LACTOBACILLUS PLANTARUM AC 11S AS A BIOCATALYST IN MICROBIAL ELECYTOLYSIS CELL

Elitsa Chorbadzhiyska, Yolina Hubenova, Sophia Yankova, Dragomir Yankov, Mario Mitov

STUDYING THE PROCESS OF DEPOSITION OF ANTIMONY WITH CALCIUM CARBONATE

K. B. Omarov, Z. B. Absat, S. K. Aldabergenova, A. B. Siyazova, N. J. Rakhimzhanova, Z. B. Sagindykova

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TEACHING CHEMISTRY AT TECHNICAL UNIVERSITY

Lilyana Nacheva-Skopalik, Milena Koleva

ФОРМИРАЩО ОЦЕНЯВАНЕ PEER INSTRUCTION С ПОМОЩТА НА PLICКERS ТЕХНОЛОГИЯТА

Ивелина Коцева, Мая Гайдарова, Галина Ненчева

VAPOR PRESSURES OF 1-BUTANOL OVER WIDE RANGE OF THEMPERATURES

Javid Safarov, Bahruz Ahmadov, Saleh Mirzayev, Astan Shahverdiyev, Egon Hassel

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РУМЕН ЛЮБОМИРОВ ДОЙЧЕВ (1938 – 1999)

Огнян Димитров, Здравка Костова

NAMING OF CHEMICAL ELEMENTS

Maria Atanassova

2014 година
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LUBRICATION PROPERTIES OF DIFFERENT PENTAERYTHRITOL-OLEIC ACID REACTION PRODUCTS

Abolfazl Semnani, Hamid Shakoori Langeroodi, Mahboube Shirani

ALLELOPATHIC AND CYTOTOXIC ACTIVITY OF ORIGANUM VULGARE SSP. VULGARE GROWING WILD IN BULGARIA

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GENDER ISSUES OF UKRAINIAN HIGHER EDUCATION

Н.H.Petruchenia, M.I.Vorovka

МНОГОВАРИАЦИОННА СТАТИСТИЧЕСКА ОЦЕНКА НА DREEM – БЪЛГАРИЯ: ВЪЗПРИЕМАНЕ НА ОБРАЗОВАТЕЛНАТА СРЕДА ОТ СТУДЕНТИТЕ В МЕДИЦИНСКИЯ УНИВЕРСИТЕТ – СОФИЯ

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Saâd Moulay Université Saâd Dahlab de Blida, Algeria

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ЕЛЕКТРОННО ПОМАГАЛO „ОТ АТОМА ДО КОСМОСА“ ЗА УЧЕНИЦИ ОТ Х КЛАС

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ВИСША МАТЕМАТИКА ЗА УЧИТЕЛИ, УЧЕНИЦИ И СТУДЕНТИ: ДИФЕРЕНЦИАЛНО СМЯТАНЕ

Б. В. Тошев Българско дружество за химическо образование и история и философия на химията

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BOTYU ATANASSOV BOTEV

Zdravka Kostova, Margarita Topashka-Ancheva

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Maria Atanassova, Radoslav Angelov

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КАК ДА МОТИВИРАМЕ УЧЕНИЦИТЕ OT VII КЛАС ДА УЧАТ

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DIFFERENTIAL TEACHING IN SCHOOL SCIENCE EDUCATION: CONCEPTUAL PRINCIPLES

G. Yuzbasheva Kherson Academy of Continuing Education, Ukraine

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Иваничка Буровска, Стефан Цаковски Регионален инспекторат по образованието – Ловеч

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„Образователни стандарти и природонаучна грамотност“ – това е темата на състоялата се от 25 до 27 октомври 2013 г. в Габрово 45. Национална конфе- ренция на учителите по химия с международно участие, която по традиция се проведе комбинирано с Годишната конференция на Българското дружество за химическо образование и история и философия на химията. Изборът на темата е предизвикан от факта, че развиването на природонаучна грамотност е обща тенденция на реформите на учебните програми и главна

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ЗА ХИМИЯТА НА БИРАТА

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RECASTING THE DERIVATION OF THE CLAPEYRON EQUATION INTO A CONCEPTUALLY SIMPLER FORM

Srihari Murthy Meenakshi Sundararajan Engineering College, India

CHEMICAL REACTIONS DO NOT ALWAYS MODERATE CHANGES IN CONCENTRATION OF AN ACTIVE COMPONENT

Joan J. Solaz-Portolés, Vicent Sanjosé Universitat de Valènciа, Spain

POLYMETALLIC COMPEXES: CV. SYNTHESIS, SPECTRAL, THERMOGRAVIMETRIC, XRD, MOLECULAR MODELLING AND POTENTIAL ANTIBACTERIAL PROPERTIES OF TETRAMERIC COMPLEXES OF Co(II), Ni(II), Cu(II), Zn(II), Cd(II) AND Hg(II) WITH OCTADENTATE AZODYE LIGANDS

Bipin B. Mahapatra, S. N. Dehury, A. K. Sarangi, S. N. Chaulia G. M. Autonomous College, India Covt. College of Engineering Kalahandi, India DAV Junior College, India

ПРОФЕСОР ЕЛЕНА КИРКОВА НАВЪРШИ 90 ГОДИНИ

CELEBRATING 90TH ANNIVERSARY OF PROFESSOR ELENA KIRKOVA

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SIMULATION OF THE FATTY ACID SYNTHASE COMPLEX MECHANISM OF ACTION

M.E.A. Mohammed, Ali Abeer, Fatima Elsamani, O.M. Elsheikh, Abdulrizak Hodow, O. Khamis Haji

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G. Yuzbasheva Kherson Academy of Continuing Education, Ukraine

ИЗСЛЕДВАНЕ НА РАДИКАЛ-УЛАВЯЩА СПОСОБНОСТ

Станислав Станимиров, Живко Велков

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COLORFUL EXPERIMENTS FOR STUDENTS: SYNTHESIS OF INDIGO AND DERIVATIVES

Vanessa BIANDA, Jos-Antonio CONSTENLA, Rolf HAUBRICHS, Pierre-Lonard ZAFFALON

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Mila Ivanova Luleva, Harald van der Werff, Freek van der Meer, Victor Jetten

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Рафаил ПОПОВ

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Учебни лаборатории Илюстрации от каталог на Franz Hugershoff, Лайциг, притежаван от бъдещия

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ADDRESING STUDENTS’ MISCONCEPTIONS CONCERNING CHEMICAL REACTIONS AND SYMBOLIC REPRESENTATIONS

Marina I. Stojanovska, Vladimir M. Petruševski, Bojan T. Šoptrajanov

АНАЛИЗ НА ПОСТИЖЕНИЯТА НА УЧЕНИЦИТЕ ОТ ПЕТИ КЛАС ВЪРХУ РАЗДЕЛ „ВЕЩЕСТВА И ТЕХНИТЕ СВОЙСТВА“ ПО ЧОВЕКЪТ И ПРИРОДАТА

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Васил Симеонов

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КОНЦЕПТУАЛНА СХЕМА НА УЧИЛИЩНИЯ КУРС П О ХИМИЯ – МАКР О СКОПСКИ ПОДХОД

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Sunanda S. Aswale, Shashikant R. Aswale, Aparna B. Dhote Lokmanya Tilak Mahavidyalaya, INDIA Nilkanthrao Shinde College, INDIA

SIMULTANEOUS ESTIMATION OF IBUPROFEN AND RANITIDINE HYDROCHLORIDE USING UV SPECTROPHOT O METRIC METHOD

Jadupati Malakar, Amit Kumar Nayak Bengal College of Pharmaceutical Sciences and Research, INDIA

GAPS AND OPPORTUNITIES IN THE USE OF REMOTE SENSING FOR SOIL EROSION ASSESSMENT

Mila Ivanova Luleva, Harald van der Werff, Freek van der Meer, Victor Jetten

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TEACHING THE CONSTITUTION OF MATTER

Małgorzata Nodzyńska, Jan Rajmund Paśko

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Маша Радославова, Ася Драгоева

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John Dewey (1859 – 1952)

ИНФОРМАЦИЯ ЗА СПЕЦИАЛНОСТИТЕ В ОБЛАСТТА НА ПРИРОДНИТЕ НАУКИ В СОФИЙСКИЯ УНИВЕРСИТЕТ „СВ. КЛИМЕНТ ОХРИДСКИ“ БИОЛОГИЧЕСКИ ФАКУЛТЕТ

1. Биология Студентите от специалност Биология придобиват знания и практически умения в областта на биологическите науки, като акцентът е поставен на организмово равнище. Те се подготвят да изследват биологията на организмите на клетъчно- организмово, популационно и екосистемно ниво в научно-функционален и прило- жен аспект, с оглед на провеждане на научно-изследователска, научно-приложна, производствена и педагогическа дейност. Чрез широк набор избираеми и факул- тативни курсове студентите

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УЧИТЕЛИТЕ ПО ПРИРОДНИ НАУКИ – ЗА КОНСТРУКТИВИСТКАТА УЧЕБНА СРЕДА В БЪЛГАРСКОТО УЧИЛИЩЕ

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Б. В. Тошев Българско дружество за химическо образование и история и философия на химията

ЗА ПРИРОДНИТЕ НАУКИ И ЗА ПРАКТИКУМА ПО ФИЗИКА (Иванов, 1926)

Бурният развой на естествознанието във всичките му клонове през XIX –ия век предизвика дълбоки промени в мирогледа на културния свят, в техниката и в индустрията, в социалните отношения и в държавните интереси. Можем ли днес да си представим един философ, един държавен мъж, един обществен деец, един индустриалец, просто един културен човек, който би могъл да игнорира придобив- ките на природните науки през последния век. Какви ужасни катастрофи, какви социални сътресения би сполетяло съвре

Книжка 1
MURPHY’S LAW IN CHEMISTRY

Milan D. Stojković

42-рa МЕЖДУНАРОДНА ОЛИМПИАДА ПО ХИМИЯ

Донка Ташева, Пенка Цанова

СЕМЕЙНИ УЧЕНИЧЕСКИ ВЕЧЕРИНКИ

Семейството трябва да познава училишето и училишето трябва да познава семейството. Взаимното познанство се налага от обстоятелството, че те, макар и да са два различни по природата си фактори на възпитанието, преследват една и съща проста цел – младото поколение да бъде по-умно, по-нравствено, физически по-здраво и по-щастливо от старото – децата да бъдат по-щастливи от родителите