Extension of the Hamaneh - Taylor model using the macroscopic polarization for the description of chiral smectic liquid crystals

Chiral smectic liquid crystals exhibit a series of phases, including ferroelectric, antiferroelectric and ferrielectric commensurate structures as well as an incommensurate SmCalpha phase. We carried out an extension of the phenomenological model, recently presented by M. B. Hamaneh and P. L. Taylor, based upon the distorted clock model

A simple blood test expedites the diagnosis of GLUT1 deficiency syndrome

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Empirical investigation to explore potential gains from the amalgamation of Phase Changing Materials (PCMs) and wood shavings

The reduction of gained heat, heat peak shifting and the mitigation of air temperature fluctuations are some desirable properties that are sought after in any thermal insulation system. It cannot be overstated that these factors, in addition to others, govern the performance of such systems thus their effect on indoor ambient conditions. The effect of such systems extends also to Heating, Ventilation and Air-conditioning (HVAC) systems that are set up to operate optimally in certain conditions. Where literature shows that PCMs and natural materials such as wood-shavings can provide efficient passive insulation for buildings, it is evident that such approaches utilise methods that are of a degree of intricacy which requires specialist knowledge and complex techniques, such as micro-encapsulation for instance. With technical and economic aspects in mind, an amalgam of PCM and wood-shavings has been created for the purpose of being utilised as a feasible thermal insulation. The amalgamation was performed in the simplest of methods, through submerging the wood shavings in PCM. An experimental procedure was devised to test the thermal performance of the amalgam and compare this to the performance of the same un-amalgamated materials. Comparative analysis revealed that no significant thermal gains would be expected from such amalgamation. However, significant reduction in the total weight of the insulation system would be achieved that, in this case, shown to be up to 20.94%. Thus, further reducing possible strains on structural elements due to the application of insulation on buildings. This can be especially beneficial in vernacular architectural approaches where considerably large amounts and thicknesses of insulations are used. In addition, cost reduction could be attained as wood shavings are significantly cheaper compared to the cost of PCMs

Application of an electronic tongue for Tunisian olive oils' classification according to olive cultivar or physicochemical parameters

Olive oil commercialization has a great impact on the economy of several countries, namely Tunisia, being prone to frauds. Therefore, it is important to establish analytical techniques to ensure labeling correctness concerning olive oil quality and olive cultivar. Traditional analytical techniques are quite expensive, time consuming and hardly applied in situ, considering the harsh environments of the olive industry. In this work, the feasibility of applying a potentiometric electronic tongue with cross-sensitivity lipid membranes to discriminate Tunisian olive oils according to their quality level (i.e., extra virgin, virgin or lampante olive oils) or autochthonous olive cultivar (i.e., cv Chétoui and cv Shali) was evaluated for the first time. Linear discrimination analysis coupled with the simulated annealing variable selection algorithm showed that the signal profiles of olive oils hydroethanolic extracts allowed olive oils discrimination according to physicochemical quality level (classification model based on 25 signals enabling 84 ± 9% correct classifications for repeated K-fold cross-validation), and olive cultivar (classification model based on 20 signals with an average sensitivity of 94 ± 6% for repeated K-fold cross-validation), regardless of the geographical origin and olive variety or the olive quality, respectively. The results confirmed, for the first time, the potential discrimination of the electronic tongue, attributed to the observed quantitative response (sensitivities ranging from 66.6 to +57.7 mV/decade) of the E-tongue multi-sensors towards standard solutions of polar compounds (aldehydes, esters and alcohols) usually found in olive oils and that are related to their sensory positive attributes like green and fruity.This work was financially supported by Project POCI-01–0145-FEDER-006984–Associate Laboratory LSRE-LCM and by Project UID/QUI/00616/2013–CQ-VR both funded by FEDER—Fundo Europeu de Desenvolvimento Regional through COMPETE2020-Programa Operacional Competitividade e Internacionalização (POCI)—and by national funds through FCTFundação para a Ciência e a Tecnologia, Portugal. Strategic funding of UID/BIO/04469/2013 unit is also acknowledged. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/ BD/104038/2014).info:eu-repo/semantics/publishedVersio

Inventory of the free-living marine nematode species from el Bibane Lagoon (Tunisia)

A detailed inventory of the free-living nematodes of Tunisia has been made for the northern part of Tunisia, but the southern part of the country is unexplored. El Bibane is the second largest lagoon in Tunisia. It is thus of high importance for future conservation actions, but little is known about its biodiversity. In this study, we identified 71 nematode species, belonging to 68 genera and 22 families. Richness was lowest in the central area of the lagoon where the highest percentages of mud and organic matter were found. The number of species detected in this study is high compared to other transitional environments in the Mediterranean basin, but lower than those reported for North Europe. Most of the species are typical of transitional environments or sediments rich in the fine fraction and detritus. The richest families were Cyatholaimidae and Chromadoridae, but the most frequently found species were Xyalidae, Linhomoeidae and Cyatholaimidae. Six of the species collected are new to science, seven are new records for Tunisian waters, and four are new for the Mediterranean basin. This study adds also important information to the biogeography of the phylum because some of the species detected here were previously known only for other geographical regions. Species that currently appear endemic to the Mediterranean Sea include Chromadorina metulata, Synonchiella edax, Paralongicyatholaimus mastigodes, Trichotheristus setifer and Metalinhomoeus numidicus. Data published in GBIF (doi:10.15470/wuvqpg

Inventory of the free-living marine nematode species from el Bibane Lagoon (Tunisia)

Inventari de les espècies de nematodes de vida lliure de la llacuna del Bibane (Tunísia) S’ha fet un inventari detallat dels nematodes de vida lliure de la part nord de Tunísia, però la part sud del país està inexplorada. La llacuna del Bibane és la segona més extensa de Tunísia, per la qual cosa té una importància fonamental per al desenvolupament de futures accions de conservació i cal avaluar-ne la biodiversitat. S’hi van trobar 71 espècies de nematodes, pertanyents a 68 gèneres i 22 famílies. La riquesa més baixa es va registrar a la zona central de la llacuna, on es concentren els percentatges més elevats de llot i matèria orgànica. El nombre d’espècies trobades en aquest estudi és alt si es compara amb el d’altres entorns de transició de la conca mediterrània, però més baix que els registrats al nord d’Europa. La major part de les espècies són típiques d’entorns de transició o de sediments rics en fracció fina i detrits. Les famílies més riques van ser Cyatholaimidae i Chromadoridae, però les trobades amb més freqüència van ser Xyalidae, Linhomoeidae i Cyatholaimidae. Cal posar en relleu que sis espècies recol·lectades són noves per a la ciència, set són nous registres en aigües tunisenques i quatre nous registres a la conca mediterrània. Aquest estudi també aporta informació important per a la biogeografia del fílum atès que fins ara algunes de les espècies registrades aquí només eren conegudes en altres regions geogràfiques. Entre les espècies que en aquest moment apareixen com a endèmiques al mar Mediterrani es troben Chromadorina metulata, Synonchiella edax, Paralongicyatholaimus mastigodes, Trichotheristus setifer i Metalinhomoeus numidicus. Dades publicades a GBIF (doi:10.15470/wuvqpg)A detailed inventory of the free-living nematodes of Tunisia has been made for the northern part of Tunisia, but the southern part of the country is unexplored. El Bibane is the second largest lagoon in Tunisia. It is thus of high importance for future conservation actions, but little is known about its biodiversity. In this study, we identified 71 nematode species, belonging to 68 genera and 22 families. Richness was lowest in the central area of the lagoon where the highest percentages of mud and organic matter were found. The number of species detected in this study is high compared to other transitional environments in the Mediterranean basin, but lower than those reported for North Europe. Most of the species are typical of transitional environments or sediments rich in the fine fraction and detritus. The richest families were Cyatholaimidae and Chromadoridae, but the most frequently found species were Xyalidae, Linhomoeidae and Cyatholaimidae. Six of the species collected are new to science, seven are new records for Tunisian waters, and four are new for the Mediterranean basin. This study adds also important information to the biogeography of the phylum because some of the species detected here were previously known only for other geographical regions. Species that currently appear endemic to the Mediterranean Sea include Chromadorina metulata, Synonchiella edax, Paralongicyatholaimus mastigodes, Trichotheristus setifer and Metalinhomoeus numidicus. Data published in GBIF (doi:10.15470/wuvqpg)Inventario de las especies de nematodos de vida libre de la laguna de El Bibane (Túnez) Se ha realizado un inventario detallado de los nematodos de vida libre de la parte norte de Túnez, pero la parte sur del país está inexplorada. La laguna de El Bibane es la segunda más extensa de Túnez, por lo que su importancia es fundamental para el desarrollo de futuras acciones de conservación y su biodiversidad debe ser evaluada. Se encontraron 71 especies de nematodos, pertenecientes a 68 géneros y 22 familias, registrándose la menor riqueza en la zona central de la laguna, donde se concentran los porcentajes más elevados de lodo y materia orgánica. El número de especies halladas en este estudio es elevado si se compara con el de otros entornos de transición de la cuenca mediterránea, pero más bajo que los registrados en el norte de Europa. La mayor parte de las especies son típicas de entornos de transición o de sedimentos ricos en fracción fina y detritos. Las familias más ricas fueron Cyatholaimidae y Chromadoridae, pero las halladas con mayor frecuencia fueron Xyalidae, Linhomoeidae y Cyatholaimidae. Merece destacarse que seis especies recolectadas son nuevas para la ciencia, siete son nuevos registros en aguas tunecinas y cuatro nuevos registros en la cuenca mediterránea. Este estudio aporta asimismo información importante para la biogeografía del filo puesto que hasta ahora algunas de las especies registradas aquí eran conocidas únicamente en otras regiones geográficas. Entre las especies que en este momento aparecen como endémicas en el mar Mediterráneo se encuentran Chromadorina metulata, Synonchiella edax, Paralongicyatholaimus mastigodes, Trichotheristus setifer y Metalinhomoeus numidicus. Datos publicados en GBIF (doi:10.15470/wuvqpg

Synergistic antifungal activity and potential mechanism of action of a glycolipid like compound produced by Streptomyces blastmyceticus S108 against Candida clinical isolates

Ayed A, Essid R, Mankai H, et al. Synergistic antifungal activity and potential mechanism of action of a glycolipid like compound produced by Streptomyces blastmyceticus S108 against Candida clinical isolates. Journal of Applied Microbiology . 2023: lxad246.AIM: The present study aimed to investigate a novel antifungal compound produced by Streptomyces blastmyceticus S108 strain. Its effectiveness against clinical isolates of Candida species and its synergistic effect with conventional antifungal drugs were assessed and its molecular mechanism of action was further studied against C. albicans.; METHODS AND RESULTS: A newly isolated strain from Tunisian soil, Streptomyces blastmyceticus S108, showed significant antifungal activity against Candida species by well diffusion method. The butanolic extract of S108 strain supernatant exhibited the best anti-Candida activity with a minimal inhibitory concentration (MIC) value of 250 mug mL-1, determined by the microdilution method. The bio-guided purification steps of the butanolic extract were performed by chromatographic techniques. Among the fractions obtained, F13 demonstrated the highest level of activity, displaying a MIC of 31.25 mug mL-1. Gas Chromatography-Mass Spectrometry (GC-MS) and Electrospray Ionisation Mass Spectrometry (ESI-MS) analyses of this fraction (F13) revealed the glycolipidic nature of the active molecule with a molecular weight of 685.6 m/z. This antifungal metabolite remained stable to physicochemical changes and did not show hemolytic activity even at 4 MIC corresponding to 125 g mL-1 towards human erythrocytes. Besides, the glycolipid compound was combined with 5-flucytosine and showed a high synergistic effect with a FICI value 0.14 against C. albicans ATCC 10231. This combination resulted in a decrease of MIC values of 5-flucytosine and the glycolipid-like compound by 8 and 64-fold, respectively. The examination of gene expression in treated Candida albicans cells by qPCR revealed that the active compound tested alone or in combination with 5-flucytosine blocks the ergosterol biosynthesis pathway by down regulating the expression of ERG1, ERG3, ERG5, ERG11 and ERG25 genes.; CONCLUSION AND IMPACT OF THE STUDY: The new glycolipid like compound, produced by Streptomyces S108 isolate, could be a promising drug for medical use against pathogenic Candida isolates. © The Author(s) 2023. Published by Oxford University Press on behalf of Applied Microbiology International