Thermal Performance of Vacuum Insulated Window Shutter Systems

Windows are a major area of heat loss in buildings losing up to 10 times more energy compared to other building elements. Thermal shutters are used to improve the energy performance of windows in both hot and cold climatic conditions. The performance of thermal shutters however greatly depends on the thermal insulation and construction detailing, specifically cold-bridging, through the shutter, as well as between the shutter and window frames. This study evaluates the effects of cold-bridging, trickle ventilation and the size of the air cavity, between the vacuum insulated shutter and the window, on the performance of window thermal shutters. Thermal simulations are conducted in VOLTRA (Thermal analysis software) to assess the conditions. The results indicate that although thermal shutters reduce heat-loss through windows, their performance could be significantly affected by cold-bridging by up to 90%. The additional thermal resistance due to the air cavity and the ventilation through the trickle vent appeared to be much less significant compared to the effects of thermal bridging

The uses of ethyl 2-(1H-benzo[D]imidazol-2-yl)acetate to synthesis pyrazole, thiophene, pyridine and coumarin derivatives with antitumor activities

In the present work, the ethyl 2-(1H-benzo[d]imidazol-2-yl)acetate (3) was subjected to a series of  heterocyclization reactions through its reaction with different chemical reagents. The resulting molecules were thiophene, pyrazole, coumarin derivatives incorporated benzo[d]imidazole moiety. All the synthesized compounds were determined by elemental analysis, 1H NMR, 13C NMR, and MS. The antitumor evaluations of the newly synthesized products toward the three cancer cell lines MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), and SF-268 (CNS cancer) showed that compounds 5a, 9b, 9c, 17, 23b and 38 were of the highest potencies among the synthesized compounds.               KEY WORDS: Oxobutanamide, Thiophene, Pyrazole, Pyran, Pyridine Bull. Chem. Soc. Ethiop. 2018, 32(3), 541-557.DOI: https://dx.doi.org/10.4314/bcse.v32i3.1

Novel synthesis of pyran-3-hydrazide derivatives and their uses to the synthesis hydrazide-hydrazone, pyrazole and thiazole derivatives with anticancer activities

ABSTRACT. The multi-component reaction of ethyl acetoacetate with each of malononitrile (3) benzaldehyde (1) in ethanol containing triethylamine gave the ethyl 6-amino-5-cyano-2-methyl-4-phenyl-4H-pyran-3-carboxylate (4). The latter compound reacted with hydrazine hydrate to give the hydrazide derivative 6. Compound 6 underwent a series of hetero-cyclization reactions to give pyrzole, hydraide-hydrazone, thiazole derivatives. The produced compounds tested against cancer cell lines six cancer cell lines and showed that compounds 8b, 10b, 11a, 17a, 21 and 24a were the most cytotoxic compounds. Further tests of the latter compounds toward the five tyrosine kinases and Pim-1 kinase showed that compounds 10b, 21 and 24a were the most potent of the tested compounds and compounds 10a, 11a and 17a were of the highest inhibitions toward Pim-1 kinase. The high inhibitions of most of the tested compounds toward the selected cancer cell lines and the tyrosine kinases encourage for future work to be done.                     KEY WORDS: Hydrazide, Thiophene, Pyrazole, Pyran, Cytotoxicity, Tyrosine kinases   Bull. Chem. Soc. Ethiop. 2021, 35(3), 573-586.  DOI: https://dx.doi.org/10.4314/bcse.v35i3.

Syntheses of heterocyclic derivatives as potential cytotoxic compounds evaluated toward hepatocellular and cervical carcinoma cell lines

ABSTRACT. Through the present work the 3-oxo-N,3-diphenylpropamide derivatives 5a,b were used to synthesize pridine, pyrazole and thiophene derivatives. 3-Phenylisoxazol-5(4H)-one produced from the reaction of ethyl benzoylacetate was used as the key starting compound for different multi-component reactions. The synthesized compounds were evaluated toward Hepatocellular carcinoma HepG2 and cervical carcinoma HeLa cell lines. Compounds 3b, 5b, 7b, 7d, 9c, 9d, 15e, 15f, 16b, 18b, 18e, 18f, 19e and 19f were the most cytotoxic compounds against the tested cell lines. The results obtained in this work encourage further work in the future to produce new cytotoxic compounds.   KEY WORDS: Diphenylpropamide, 3-Phenylisoxazole, Pyran, Pyridine, Cytotoxicity Bull. Chem. Soc. Ethiop. 2023, 37(1), 141-158.                                                              DOI:https://dx.doi.org/10.4314/bcse.v37i1.1

Simulations of a lattice model of two-headed linear amphiphiles: influence of amphiphile asymmetry

Using a 2D lattice model, we conduct Monte Carlo simulations of micellar aggregation of linear-chain amphiphiles having two solvophilic head groups. In the context of this simple model, we quantify how the amphiphile architecture influences the critical micelle concentration (CMC), with a particular focus on the role of the asymmetry of the amphiphile structure. Accordingly, we study all possible arrangements of the head groups along amphiphile chains of fixed length $N=12$ and 16 molecular units. This set of idealized amphiphile architectures approximates many cases of symmetric and asymmetric gemini surfactants, double-headed surfactants and boloform surfactants. Consistent with earlier results, we find that the number of spacer units $s$ separating the heads has a significant influence on the CMC, with the CMC increasing with $s$ for $s<N/2$. In comparison, the influence of the asymmetry of the chain architecture on the CMC is much weaker, as is also found experimentally.Comment: 30 pages, 17 fgure

Discovery of new thiophene, pyrazole, isoxazole derivatives as antitumor, c-Met, tyrosine kinase and Pim-1 kinase inhibitors

The reaction of cyclohexan-1,3-dione (1) with ethyl orthoformate (2) in acetic acid gave the 2-(ethoxymethylene)cyclohexane-1,3-dione (3). The latter compound was used for further heterocyclization reactions to give thiophene, pyrazole and pyran derivatives. The cytotoxicity of the newly synthesized compound against the six cancer cell lines NUGC, DLDI, HA22T, HEPG2, HONE1 and MCF showed that compounds 5, 10c, 10d, 13b, 14a, 18b, 18d, 18e and 20b were the most potent compounds. On the other hand, the toxicity of these compounds against shrimp larvae indicated that compounds 7a, 10c, 13b, 14a, 18b and 18d were non toxic against the tested organisms. Inhibition of the most potent compounds towards the tyrosine kinases c-kit, FIT-3, Vascular Endothelial Growth Factor Receptor (VEGFR)-2, Estimated Glomerular Filtration Rate (EGFR) and Platelet-Derived Growth Factor Receptor (PDGFR) revealed that compounds 5, 10c, 10d, 13b, 18b, 18d, 18e and 20b were of the highest inhibitory effect. The Pim-1 kinase test revealed that compounds 10d, 18b and 20b were of the highest inhibitory effect. In addition, the c-Met enzymatic activities showed that compounds 10c, 10d, 18b, 18e, 19 and 20b showed higher potencies against c-Met kinase than the reference foretinib. On the other hand, compounds 7a, 7b, 10d, 13a, 13b, 14a, 14b, 16a, 16b, 17, 18a-f, 19 and 20 showed higher inhibition towards PC-3 cell line than the reference SGI-1776. Compounds 10c and 18b were of common potencies and their molecular docking was described.               KEY WORDS: Cyclohexane 1,3-dione, Pyrazole, Thiophene, Cytotoxicity, Tyrosine kinases Bull. Chem. Soc. Ethiop. 2018, 32(2), 285-308.DOI: https://dx.doi.org/10.4314/bcse.v32i2.

Synthesis and cytotoxicity evaluation of thiazole derivatives obtained from 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile

Reactivity of 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile towards thioglycolic acid resulted in thiazole derivative 1. The latter reacted with different chemical reagents to give thiazole, pyrano[2,3-d]thiazole and thiazolo[4,5-d]thiazole derivatives. Cytotoxicity effects of the newly synthesized products against six cancer cell lines, namely, human gastric cancer (NUGC), human colon cancer (DLD-1), human liver cancer (HA22T and HEPG-2), human breast cancer (MCF) and nasopharyngeal carcinoma (HONE-1) as well as against a normal fibroblast cell (WI-38) were evaluated. The study showed that the 4,5,6,7 tetrahydrobenzo[b]thiophene derivatives 6a, 7, 8a,b, 9b and 10b,c were the most active compounds. Their potencies were attributed to the presence of the electron withdrawing groups

Uses of chalcone acetophenone to synthesis heterocyclic compounds with cytotoxic and c-Met kinase activities

ABSTRACT. The aim of present study was the uses of a series of α,β-unsaturated carbonyl compounds (chalcones), in the synthesis of pyridine, pyran, thiophene, thiazole, together with their uses in heterocyclic synthesis. The work has resulted in the synthesis of a variety of 2,5-dihydropyridine, hydrazide-hydrazone, thiophene derivatives, coumarin, pyran and thiazolo[4,5-d]thiazole derivatives. The antitumor activities of the newly synthesized products were carried out against three cancer cell lines namely MCF-7, NCI-H460 and SF-268 and normal human cell line WI38.&nbsp; In addition, the inhibitions of most of the synthesized compounds against &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c-Met kinase were studied and results showed that many compounds were of high inhibitions, and these are considered as promising anticancer agents. The results obtained encouraged further work in the future.&nbsp; &nbsp; KEY WORDS: Chalcones, Heterocyclic, Pyridine, Pyran, Thiophene, Thiazole, Antitumor Bull. Chem. Soc. Ethiop. 2022, 36(1), 149-172.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; DOI: https://dx.doi.org/10.4314/bcse.v36i1.13&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp

Simulations of a lattice model of two-headed linear amphiphiles: influence of amphiphile asymmetry

Using a 2D lattice model, we conduct Monte Carlo simulations of micellar aggregation of linear-chain amphiphiles having two solvophilic head groups. In the context of this simple model, we quantify how the amphiphile architecture influences the critical micelle concentration (CMC), with a particular focus on the role of the asymmetry of the amphiphile structure. Accordingly, we study all possible arrangements of the head groups along amphiphile chains of fixed length $N=12$ and 16 molecular units. This set of idealized amphiphile architectures approximates many cases of symmetric and asymmetric gemini surfactants, double-headed surfactants and boloform surfactants. Consistent with earlier results, we find that the number of spacer units $s$ separating the heads has a significant influence on the CMC, with the CMC increasing with $s$ for $s<N/2$. In comparison, the influence of the asymmetry of the chain architecture on the CMC is much weaker, as is also found experimentally.Comment: 30 pages, 17 fgure

Performance gap? energy, health and comfort needs in buildings

Research on performance gap suggests that the actual energy consumption in buildings can be twice as much as expected. Energy models rely on predictive indicators and assumptions that are usually done at design stage, without acknowledging behavioural patterns of actual users. Moreover, in the context of performance gap, it is evident that energy efficiency is overemphasised while other key issues such as health and comfort of occupants, indoor air quality, noise levels etc. have been less stressed and discussed. This paper discusses the performance gap using surveys and physical measurements in a case study building at the University of Cambridge and reports findings of a research workshop with graduate students working on environmental performances of the built environment. The workshop addressed research issues related to energy, comfort and health, used as a method to understand the complexities of and trade-off between different aspects of sustainable buildings. According to the results, it is possible to balance energy, health and comfort needs in building projects. Lessons can be learned from the university’s old and new building projects to inform future research and policies