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As the descendants of stars with masses less than 8 M ⊙ on the main sequence, white dwarfs provide a unique way to constrain planetary occurrence around intermediate-mass stars (spectral types BAF) that are otherwise difficult to measure with radial-velocity or transit surveys. We update the analysis of more than 250 ultraviolet spectra of hot (13,000 K < T eff < 30,000 K), young (less than 800 Myr) white dwarfs collected by the Hubble Space Telescope, which reveals that more than 40% of all white dwarfs show photospheric silicon and sometimes carbon, signposts for the presence of remnant planetary systems. However, the fraction of white dwarfs with metals significantly decreases for massive white dwarfs (M WD > 0.8 M ⊙), descendants of stars with masses greater than 3.5 M ⊙ on the main sequence, as just 11 − 4 + 6 % exhibit metal pollution. In contrast, 44% ± 6% of a subset of white dwarfs (M WD < 0.7 M ⊙) unbiased by the effects of radiative levitation are actively accreting planetary debris. While the population of massive white dwarfs is expected to be influenced by the outcome of binary evolution, we do not find merger remnants to broadly affect our sample. We connect our measured occurrence rates of metal pollution on massive white dwarfs to empirical constraints of planetary formation and survival around stars with masses greater than 3.5 M ⊙ on the main sequence. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the effective‑ ness of a health education program on mothers' knowledge and practices related to amebiasis. Pre‑ and post‑I and II‑tests were used, along with a two‑group quasi‑experimental design. The study included a convenience sample of 120 mothers, including 60 from the study and 60 from the control group. Out of the entire number of PHCs in Wasit Governorate, seven were used for the study. A three‑part structured questionnaire tests mothers' knowledge of the illness and attitudes about it. The results of this study indicated that there is statistically significant difference between the study and control groups during the post‑test I and post‑test II periods (t=14.968, P=.000 and t=13.731, P=.000, respectively). Data from the study group during the pre‑test period of 31.17(9.14) revealed that (70%) of mothers had bad practices connected to Entameba Histolytica among children. According to the post‑test I results, 47.4 (9.48) respondents, or 70%, identified good practices. The main finding showed that, after the educational program was implemented, mothers' knowledge and practice of amebiasis dramatically increased, with pre‑post implementation differ‑ ences that are statistically significan [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic has presented various challenges, one of which is the discovery that after the acute episode, around 30% of patients experience persistent symptoms or develop new ones, now known as long COVID. This new disease has significant social and financial impacts. The objective is to determine the prevalence of long COVID in the Tunisian population and identify its predictive factors. Methods: This was a cross-sectional study conducted among Tunisians who were infected with COVID-19 between March 2020 and February 2022. An online self-administered questionnaire was distributed through social media, radio, and television channels over the course of one month (February 2022). Long COVID was defined as the persistence of existing symptoms or the development of new symptoms within three months after onset, lasting for at least two months, and with no differential diagnosis. We performed univariate and multivariate analyses using binary stepwise logistic regression with a significance level set at 5%. Results: A total of 1911 patients participated in our study, and the prevalence of long COVID was 46.5%. The two most frequent categories were general and neurological post-COVID syndrome, with a prevalence of 36.7% each. The most commonly observed symptoms were fatigue (63.7%) and memory problems (49.1%). In the multivariate analysis, the predictive factors for long COVID were female gender and age of 60 years or older, while complete anti-COVID vaccination was found to be a protective factor. Conclusions: Our study found that complete vaccination was a protective factor against long COVID, while female gender and age of 60 years or older were identified as the main risk factors. These findings are consistent with studies conducted on other ethnic groups. However, many aspects of long COVID remain unclear, including its underlying mechanisms, the identification of which could guide the development of potential effective treatments. [ABSTRACT FROM AUTHOR]

Chréa National Park, one of the 11 national parks in Algeria, is natural and diverse but under different pressures: urbanisation, fires caused by the high flux of visitors. Several ecological and systematic studies have been conducted on the Araneae, the most important epigeal fauna, but no attention was given to the anthropogenic parcels of the Park. To assess the effects of urbanisation and fires on the ecology of this fauna, spiders were collected monthly for 2 years, using 'Pitfall' traps in three disturbed stations: burned, urbanised and reforested and three natural sites as control. In total, 1,476 specimens were sampled (19 families, 42 genera and 68 species). Zodarion algericum was the dominant species (13.25%), particularly in the burned station. Mann–Whitney U test showed a significant difference between urbanised and nonurbanised sites in contrast to other ones and no significant differences with the control. Our results show that fires transform the forest into a mosaic of habitats, with open gaps of different stages of succession. In addition, the reforestation of cedars without any agricultural practices has no negative effects on the Park. No loss of biodiversity was observed; this would encourage the restoration of the forest to protect its fauna and flora. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new calix [4] arene functionalized at the upper rim by protected ethylenediamine groups has been successfully synthesized. • The synthetize calix [4] arene was characterized by using elemental analysis 1H NMR, 13C NMR, and HRMS. • Indium tin oxide electrode (ITO) modified with the calix [4] arene derivative (EDCA [4]) was successfully prepared using a simple drop-cost method. The antibiotic oxytetracycline (OTC), from the tetracycline family of drugs, is generally used to enhance growth as well as to prevent and cure harmful microorganisms in animals and aquaculture. However, improper OTC use exposes people to trace amounts of antibiotics in the food chain, increasing their risk of health problems. For the first time, a new calix [4] arene functionalized at the upper rim by protected ethylenediamine groups has been successfully synthesized and fully characterized by using elemental analysis 1H NMR, 13C NMR, and HRMS. Moreover, indium tin oxide electrode (ITO) modified with the calix [4] arene derivative (EDCA [4]) was successfully prepared using a simple drop-cost method. EDCA [4] film was characterized by static contact angle measurement, cyclic voltammetry measurement, electrochemical impedance spectroscopy, and microscopic surface imaging (SEM). Electrochemical impedance spectroscopy (SIE) measurement showed that the EDCA [4]/ITO exhibited high molecular recognition and consequently displayed a good impedimetric response toward oxytetracycline (OTC). The developed sensor exhibited a wide linear concentration range of 10−10M to 10−5M and a lower detection limit of 2.3 10−11 M. Also, the presented sensor has demonstrated great selectivity and reproducibility, and the designed electrochemical platform was successfully used for detecting trace oxytetracycline in spiked milk samples. [ABSTRACT FROM AUTHOR]

In order to improve photovoltaic efficiency, researches have been carried out on silicon nanowires (SiNWs). In this article, we report a comparative study between silicon substrate (Si) and SiNWs developed by a metal-assisted chemical etching (Ag) method at different etching times (25, 10 and 5 min). Scanning electron microscopy (SEM), transmission electron microscopy and X-ray diffraction were used to collect the morphological and structural information on the SiNWs. Raman spectroscopy shows that the intensity of the nanowires is 4 to 10 times higher than that of the substrate, and increases with increase in etching time. The total reflectance of SiNWs reduced to less than 5% over the entire visible range. The low reflectance and zero transmittance of SiNWs lead to higher absorbance in the visible wavelength range. The SiNW-etched nanowire structure (25 min) works best for capturing light, we believe that having longer nanowires improves the optical working of the nanostructures and may be a potential candidate for high efficiency photovoltaic solar cells and other optic devices. [ABSTRACT FROM AUTHOR]

DNA hemicatenanes (HCs) are four-way junctions in which one strand of a doublestranded helix is catenated with one strand of another double-stranded DNA. Frequently mentioned as DNA replication, recombination and repair intermediates, they have been proposed to participate in the spatial organization of chromosomes and in the regulation of gene expression. To explore potential roles of HCs in genome metabolism, we sought to purify proteins capable of binding specifically HCs by fractionating nuclear extracts from HeLa cells. This approach identified three RNA-binding proteins: the Tudor-staphylococcal nuclease domain 1 (SND1) protein and two proteins from the Drosophila behavior human splicing family, the paraspeckle protein component 1 and the splicing factor proline- and glutamine-rich protein. Since these proteins were partially pure after fractionation, truncated forms of these proteins were expressed in Escherichia coli and purified to near homogeneity. The specificity of their interaction with HCs was re-examined in vitro. The two truncated purified SND1 proteins exhibited specificity for HCs, opening the interesting possibility of a link between the basic transcription machinery and HC structures via SND1. [ABSTRACT FROM AUTHOR]

A nonlinear difference scheme is considered for the two-dimensional Rosenau–Burgers equation. Some priori estimates, existence and uniqueness of the difference solution have been shown. A second-order convergence in the uniform norm and stability are proved. Also a convergent iterative algorithm is presented. All results are obtained without any restrictions on the meshsizes. At last numerical experiments are carried out to support the theoretical claims. [ABSTRACT FROM AUTHOR]

By using photoluminescence spectroscopy and scanning near-field optical microscopy, the local effect of In/Ga intermixing between InAs quantum-dot layers and InGaAs and/or GaAs layers has been investigated in 5 and 20 stacked InAs/In 0.11 Ga 0.89 As/GaAs self-assembled quantum-dot solar cells. The photoluminescence spectra show two peaks due to a bimodal size distribution of the quantum dots. By increasing the number of quantum-dot stacks, a red shift of the ground-state emission energy of 70 meV (100 meV) for the entity of quantum dots with small (large) size and a decrease of the intensity in combination with an increase of the width of the peaks is observed. The red shift is attributed to three effects: (i) formation of a mini band caused by the electronic coupling of islands in the vertical direction, (ii) increase of the quantum dots size caused by strain-field coupling, and (iii) In/Ga intermixing. The increases of the peak width and the reduction of the intensity is explained by the creation of non-radiative recombination centers. Using near-field optical microscopy to map the topography and to measure the local photocurrent, the non-radiative recombination centers can be tentatively identified. [ABSTRACT FROM AUTHOR]

The freshwater fish, Barbus callensis (Valenciennes, 1842) was studied from 2005 to 2007 for the first time in Hamiz dam. This species endemic of North African continent is widely spread in the rivers of Algeria. This reservoir is situated in Boumerdes 35 km southeast of Algiers. During these three years, the monthly sampling was carried out by trammel nets, fishing near the dike during one night. At the same time, the fry was captured with a transparent plastic bottle baited with breadcrumbs put down near the lakeshore. The monthly follow-up of the gonadosomatic ratio (RGS) reveals that the spawning period occurred between April and May. The evolution of the condition factor (K) shows low seasonal variations. However, a lower value appears in spring when the temperature increases and the breeding begins. The sex ratio is higher for the adult females (1:2.8, more than 26 cm). The first sexual maturity size (L50) is lower for males (19.6 cm) than for females (27.7 cm). [ABSTRACT FROM AUTHOR]

The near-field photocurrent mapping of InAs/InGaAs/GaAs quantum-dots intermediate-band solar cells by means of scanning near-field optical microscopy is discussed. By illumination through the InZn top contact at two different wavelengths (visible, 800 nm, and near infrared, 1150 nm), topography and photocurrent information were simultaneously collected. The lateral resolution was ~100 nm. A strong correlation between topography and local photocurrent has been observed which is attributed to efficient photocarrier generation in intermediate-band solar cells. We found that this is due to the presence of photocarrier transfer from quantum dots to the InGaAs strain-compensated layer or to the GaAs spacer layer. Furthermore, a reduced local photocurrent was found right on top of the InAs quantum dot which has been explained by trapping of photo-generated electrons from the GaAs region by InAs quantum-dot states. The effect of the thickness of the GaAs spacer layer and the effect of Si-delta doping on topography and photocurrent distribution are also discussed. [ABSTRACT FROM AUTHOR]

Thin films of poly[2-methoxy-5-(20-ethylhexyloxy)-1,4 phenylenevinylene] (MEH-PPV), 5,17-bis(4-nitrophenylazo)-26,28-dihydroxy-25,27-di(ethoxycarbonylmethoxy)-calix[4]arene (azo-calix[4]arene) and MEH-PPV doped azo-calix[4]arene, with 30 wt% and 70 wt% doping ratios, were prepared from chloroform solution by spin coating technique on quartz and ITO substrates. Morphological and optical properties of the samples were investigated by scanning electron microscopy (SEM) and UV–visible spectrophotometry techniques, respectively. Further, the charge carrier transport properties and conduction mechanism of the composite MEH-PPV:azo-calix[4]arene thin films based junction were studied by using current–voltage ( I–V ) characteristics and dielectric spectroscopy technique. I–V characteristic of ITO/MEH-PPV:azo-calix[4]arene/Al devices showed that the space charge limited conduction (SCLC) dominates in the high voltage region. Moreover, frequency dependence of ac conductivity obeys Jonscher's universal power law. Finally, dielectric constant ( ε ′), dielectric loss ( ε ″) and loss tangent (tan δ ) were investigated as function of amount of azo-calix[4]arene in the MEH-PPV polymer matrix. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the impact of emotional eliciting pictures on neuromuscular performance during repetitive supramaximal cycling exercises (RSE). In a randomized order, twelve male participants were asked to perform five 6-s cycle sprints (interspaced by 24 s of recovery) on a cycle ergometer in front of neutral, pleasant or unpleasant pictures. During each RSE, mean power output (MPO) and electromyographic activity [root mean square (RMS) and median frequency (MF)] of the vastus lateralis and vastus medialis muscles were analyzed. Neuromuscular efficiency (NME) was calculated as the ratio of MPO to RMS. Higher RMS (232.17 ± 1.17 vs. 201.90 ± 0.47 μV) and MF (68.56 ± 1.78 vs. 64.18 ± 2.17 Hz) were obtained in pleasant compared to unpleasant conditions (p < 0.05). This emotional effect persisted from the first to the last sprint. Higher MPO was obtained in pleasant than in unpleasant conditions (690.65 ± 38.23 vs. 656.73 ± 35.95 W, p < 0.05). However, this emotional effect on MPO was observed only for the two first sprints. NME decreased from the third sprint (p < 0.05), which indicated the occurrence of peripheral fatigue after the two first sprints. These results suggested that, compared with unpleasant pictures, pleasant ones increased the neuromuscular performance during RSE. Moreover, the disappearance of the beneficial effect of pleasant emotion on mechanical output from the third sprint appears to be due to peripheral fatigue. [ABSTRACT FROM AUTHOR]

A novel optical sensor for sensitive and selective determination of copper ions in aqueous solution based on a novel calix[4]dicyano-diimidazole ionophore was prepared. The newly synthesized calix[4]dicyano-diimidazole exhibited obvious absorbance enhancement at 284 nm in the presence of copper ions. At pH 6.8, the measuring range of the optode membrane for Cu 2+ ions was from 1.0 × 10 −8 to 1.0 × 10 −4 M with a detection limit of 7.0 × 10 −9 M. Furthermore, the response time of the proposed optical device was within 10 min. With the optimum condition described, the optical sensor revealed good selectivity toward Cu 2+ ions in comparison with common coexisting cations (Hg 2+ , Pb 2+ , Cd 2+ , Ni 2+ and Zn 2+ ). Finally, the reproducibility, regeneration, reversibility and repeatability of this optical sensor were discussed. [ABSTRACT FROM AUTHOR]

The hypothesis that ethnicity and sport practice influence the relationship between maximal power in cycling ( Pmax) and countermovement jump ( CMJ) has been studied by relating CMJ and Pmax in two groups (volleyball players, VB, and physical education students, PES) including subjects with Caucasian (67 C) or West African (39 WA) origins. Maximal power of the arms ( Pmax Arms) was also measured. A two-way analysis of variance (groups × ethnicity) showed significant effects of both factors upon CMJ, which was higher in WA and VB, P = 0.002 and P < 0.001, respectively. Within WA, CMJ was significantly higher in VB (0.732 ± 0.057 m) than in PES (0.661 ± 0.082 m), although there was no difference in Pmax (14.7 ± 1.7 vs 14.7 ± 1.9 W/kg). CMJ was significantly higher in WA (0.69 ± 0.08 vs 0.65 ± 0.09 m in C, P = 0.002) without significant interethnic difference in Pmax (14.7 ± 1.8 in WA, and 14.8 ± 1.9 W/kg in C). The CMJ- Pmax relationships were different in C and WA ( P = 0.003). Therefore, CMJ predicted from Pmax would be underestimated in WA. The same difference was observed for the relationship between CMJ and Pmax Arms. These results were confirmed by the comparison with previous Pmax- CMJ relationship in the literature, collected in Caucasian and African subjects with the same protocols. [ABSTRACT FROM AUTHOR]

In this paper, an optical sensor was proposed for sensitive determination of copper (II) ions in aqueous solution. The sensing membrane was prepared by coating β-ketoimine calix[4]arene derivative as ionophore on a glass plate surface. Thin β-ketoimine calix[4]arene layer was characterized by contact angle measurements showing a good surface coverage. Besides, a smooth and homogeneous morphology of the calixarene membrane was examined by atomic force microscopy (AFM). The response of the optode is based on the decrease in the absorbance signal at 309 nm upon exposure to buffer solutions containing Cu 2 + ions. At a pH 6.8, the proposed sensor displays a calibration response for copper over a wide concentration range of 1.0 × 10 − 7 M to 1.0 × 10 − 4 M with a detection limit of 2.0 × 10 − 8 M and response time of 7–10 min. This optode exhibits good selectivity toward copper ions in comparison with common ions including Hg 2 + and Ag + ions. The copper sensing film can be regenerated using 0.01 M HNO 3 solution. In addition to its high stability, repeatability and reproducibility, the sensor shows operational life time of 4 weeks. [ABSTRACT FROM AUTHOR]

The primary aim of our study was to assess the role of ultrasound in diagnosing gestational trophoblastic disease and to correlate ultrasound imaging with histopathological findings. Lutein cysts were found in 21 cases, 13 were bilateral and 8 were unilateral, their mean size was 6 cm. Conclusions Ultrasound is not sufficient to diagnose the gestational trophoblastic disease, a histopathology analysis of the trophoblastic tissu have to confirm the suspicion. [Extracted from the article]

The first trimester ultrasound showed a single fetus of approximately 13 weeks of gestation, fetal motion and cardiac activity were present. Neural tube defect is a congenital malformation in which the closure of the neural tube is incomplete, this condition can be mild to severe and the defects are rarely multiple. [Extracted from the article]

Drug‐induced tubulointerstitial nephritis is an uncommon complication in patients on anti‐tuberculosis therapy that can lead to permanent kidney damage. Rifampicin is the most offending drug. We report a case of a 41‐years old man being treated for pulmonary tuberculosis and presenting with tubulointerstitial nephritis associated with rifampicin. We focus on diagnosis features and therapeutic challenges. [ABSTRACT FROM AUTHOR]

The article discusses research which was conducted to investigate the effect two braking forces, one with 8.7 and one with 11% of body mass, had on Wingate test performance, peak lactate ([La]pk), peak heart rate (HRpk), and rate of perceived exertion (RPE). Researchers evaluated 16 male physical education students. They found that the reliability of the Wingate test did not depend on the used load, and a braking force of 11% BM was more optimal for power output during Wingate tests.

The unitary events (UE) method is one of the most popular and efficient methods used over the past decade to detect patterns of coincident joint spike activity among simultaneously recorded neurons. The detection of coincidences is usually based on binned coincidence count (Grün, 1996), which is known to be subject to loss in synchrony detection (Grün, Diesmann, Grammont, Riehle, & Aertsen, 1999). This defect has been corrected by the multiple shift coincidence count (Grün et al., 1999). The statistical properties of this count have not been further investigated until this work, the formula being more difficult to deal with than the original binned count. First, we propose a new notion of coincidence count, the delayed coincidence count, which is equal to the multiple shift coincidence count when discretized point processes are involved as models for the spike trains. Moreover, it generalizes this notion to nondiscretized point processes, allowing us to propose a new gaussian approximation of the count. Since unknown parameters are involved in the approximation, we perform a plug-in step, where unknown parameters are replaced by estimated ones, leading to a modification of the approximating distribution. Finally the method takes the multiplicity of the tests into account via a Benjamini and Hochberg approach (Benjamini & Hochberg, 1995), to guarantee a prescribed control of the false discovery rate. We compare our new method,MTGAUE (multiple tests based on a gaussian approximation of the unitary events) and the UE method proposed in Grün et al. (1999) over various simulations, showing that MTGAUE extends the validity of the previous method. In particular, MTGAUE is able to detect both profusion and lack of coincidences with respect to the independence case and is robust to changes in the underlying model. Furthermore MTGAUE is applied on real data. [ABSTRACT FROM AUTHOR]

This study investigated the interaction between emotion-eliciting pictures and power output during a repetitive supra-maximal task on a cycle ergometre. Twelve male participants (mean (±SD) age, height and weight: 28.58 ± 3.23 years, 1.78 ± 0.05 m and 82.41 ± 13.29 kg) performed 5 repeated sprint tests on a cycle ergometre in front of neutral, pleasant or unpleasant pictures. For each sprint, mechanical (peak power and work), physiological (heart rate) and perceptual (affective load) indices were analysed. Affective load was calculated from the ratings of perceived exertion, which reflected the amount of pleasant and unpleasant responses experienced during exercise. The results showed that peak power, work and heart rate values were significantly lower (P< 0.05) for unpleasant pictures (9.18 ± 0.20 W ∙ kg−1; 47.69 ± 1.08 J ∙ kg−1; 152 ± 4 bpm) when compared with pleasant ones (9.50 ± 0.20 W ∙ kg−1; 50.11 ± 0.11 J ∙ kg−1; 156 ± 3 bpm). Furthermore, the affective load was found to be similar for the pleasant and unpleasant sessions. All together, these results suggested that the ability to produce maximal power output depended on whether the emotional context was pleasant or unpleasant. The fact that the power output was lower in the unpleasant versus pleasant session could reflect a regulatory process aimed at maintaining a similar level of affective load for both sessions. [ABSTRACT FROM PUBLISHER]

The chemical composition of essential oil hydrodistillized from Allium roseum var. grandiflorum subvar. typicum Regel. leaves was analyzed by GC and GC/MS. Nine extracts obtained from flowers, stems and leaves and bulbs and bulblets of A. roseum var. grandiflorum were tested for their total phenol, total flavonoid and total flavonol content. All these extracts and the essential oils from fresh stems, leaves and flowers were screened for their possible antioxidant and antifungal properties. The results showed that the hexadecanoic acid was detected as the major component of the leaf essential oil (75.9%). The ethyl acetate extract of stems and leaves had the highest antioxidant activity with a 50% inhibition concentration (IC50) of 0.35±0.01mg/mL of DPPH and 0.71±0.01mg/mL of ABTS +. All the extracts appeared to be able to inhibit most of the tested fungi. The essential oil of the leaves had an antifungal growth effect on Fusarium solani f. sp. cucurbitae and Botrytis cinerea (39.13 and 52.50%, respectively). This could be attributed to the presence of hexadecanoic acid, known for its strong antifungal activity. In conclusion, in addition to the health benefits of A. roseum, it can be used as an alternative pesticide in the control of plant disease and in the protection of agriculture products. [ABSTRACT FROM AUTHOR]

The chemical composition of the essential oils of different Allium nigrum L. organs and the antibacterial activity were evaluated. The study is particularly interesting because hitherto there are no reports on the antibacterial screening of this species with specific chemical composition. Therefore, essential oils from different organs (flowers, stems, leaves and bulbs) obtained separately by hydrodistillation were analyzed using gas chromatography-mass spectrometry (GC-MS). The antibacterial activity was evaluated using the disc and microdilution assays. In total, 39 compounds, representing 90.8?96.9% of the total oil composition, were identified. The major component was hexadecanoic acid (synonym: palmitic acid) in all the A. nigrum organs oils (39.1?77.2%). We also noted the presence of some sesquiterpenes, mainly germacrene D (12.8%) in leaves oil) and some aliphatic compounds such as n-octadecane (30.5%) in bulbs oil. Isopentyl isovalerate, 14-oxy-a-muurolene and germacrene D were identified for the first time in the genus Allium L. All the essential oils exhibited antimicrobial activity, especially against Enterococcus faecalis and Staphylococcus aureus. The oil obtained from the leaves exhibited an interesting antibacterial activity, with a Minimum Inhibitory Concentration (MIC) of 62.50 µg/mL against these two latter strains. The findings showed that the studied oils have antibacterial activity, and thus great potential for their application in food preservation and natural health products. [ABSTRACT FROM AUTHOR]

Highlights: [•] We report optical sensing studies of chromogenic calixarene derivatives. [•] We examine the complexation behavior of azo-calix[4]arene for metal ions. [•] We investigate the response mechanism between azo-calix[4]arene and Al3+. [•] We study characteristics of optode films for determination of aluminum traces. [Copyright &y& Elsevier]

Highlights: [•] We elaborate thin films based on MEH–PPV and MEH–PPV/β-ketoimine calix[4]arene. [•] We study the electric and dielectric characteristics of thin films. [•] We investigate the sensing properties of thin films for Cu2+ and Na+. [Copyright &y& Elsevier]

Abstract: Optical, electrical and ion sensing properties of β-ketoimine calix[4]arene thin films have been investigated. These calix[4]arene derivative films exhibit absorption spectra with a resolved electronic structure in the UV–vis and the energy gap was found to be 3.65eV. Electrical properties of ITO/β-ketoimine calix[4]arene/Al devices have been investigated by I–V characteristics and impedance spectroscopy measurements. The conduction is governed by space-charge-limited current (SCLC) mechanism. The impedance spectroscopy study showed a hopping transport process, a typical behavior of disordered materials. The device was modeled by a single parallel resistor and capacitor network in series with a resistance. The β-ketoimine calix[4]arene was used for the conception of the novel optical chemical sensor and the detection of Cu2+ ions was monitored by UV–visible spectroscopy. The linear dynamic range for the determination of Cu2+ has been 10−5–10−3.7 M with a detection limit of 10−5 M. The characteristics of this optode such as regeneration, repeatability, reproducibility, short-term stability, life time and ion selectivity have been discussed. [Copyright &y& Elsevier]

The chemical composition of the essential oils extracted from some Tunisian Hypericum species and their larvicidal activity against Culex pipiens larvae were evaluated. The chemical compositions of the essential oils from the aerial plant parts were analyzed using gas chromatography-mass spectrometry. One hundred and thirty-four compounds were identified, ranging between 85.1 and 95.4 % of the oil's composition. The components were monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, non-terpenic hydrocarbons, and others. The larvicidal activity of the essential oils was evaluated using a method recommended by WHO. Larvicidal tests revealed that essential oils from the Hypericum species have a significant larvicidal activity against C. pipiens, with LC ranging between 102.82 and 194.70 ppm. The most powerful essential oils against these larvae were Hypericum tomentosum and Hypericum humifusum samples, followed by the essential oil of Hypericum perforatum. [ABSTRACT FROM AUTHOR]

Abstract: Conducting polymer can be used as the polymer matrix of the ion sensitive membrane (containing electroactive sites), which would exhibit intrinsic mixed ionic and electronic conductivity. In this work, a soluble poly(p-phenylene vinylene) derivative (MEH-PPV) has been used as the electroconducting polymer to immobilize the ß-ketoimine calix[4]arene derivative. Indium-thin oxide (ITO) electrode coated with the thin films of MEH-PPV and composite MEH-PPV/ß-ketoimine Cal[4] are designed for the determination of trace amounts of Hg2+ ions. Surface morphology properties were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The presented results show that the incorporation of calixarene derivative into MEH-PPV polymer improved the surface smoothness. Contact angle measurements were used to study hydrophobicity and surface energy properties of thin films. We observed that the best adhesion on the ITO surface is for the MEH-PPV/ß-ketoimine Cal[4] surface due to the presence of (OH) groups coming from the molecules of derivative calix[4]arene. Thin films were characterized by electrochemical impedance spectroscopy (EIS) in the dark and under illumination. The impedance behavior of the modified electrodes is modeled by an equivalent electrical circuit using the Z-View software. From the impedance plots, the bulk resistance and ionic conductivity of the membranes is an important factor determining the ability of ions to pass across the membrane. Marked differences in the ionic conductivity are observed as a function of the light excitation. The charge transfer processes at the electrode/electrolyte interface was carefully examined in the dark and under illumination. Optical excitation of both membranes revealed that the sensing activity of the MEH-PPV/ß-ketoimine Cal[4] modified electrode can improve the measuring sensitivity of Hg2+ ions compared to the MEH-PPV modified electrode. [Copyright &y& Elsevier]

A photoelectrochemical sensor for sulfamethoxazole (SMX) detection was prepared by a simple spin coating based on [N(CH3)4]2CoCl2Br2. The prepared membrane was broadly characterized using different analytical techniques to examine its morphological, wettability, electrochemical, and optical properties. In addition, the interaction mechanism between [N(CH3)4]2CoCl2Br2 and the antibiotic was determinated using absorbance and fluorescence measurements. The impedimetric sensor has exhibited good response towards SMX presenting remarkable limit of detection (LOD) of 2.5 × 10–12 M and limit of quantification (LOQ) of 8.3 × 10–12 M in darkness. Under illumination, LOD and LOQ values have decreased to be 6.3 × 10–13 M and 2.1 × 10–12 M, respectively. The recognition capability has correlated linearly with the SMX concentration in the range of 10–11–10–5 M under the two conditions. Finally, the sensitive thin film has presented high selectivity towards the cibled antibiotic, as well as good regeneration, repeatability and reproducibility. [ABSTRACT FROM AUTHOR]

Abstract: Selective and sensitive optical sensor membranes (optodes) were elaborated to detect cations in aqueous solutions. The sensing films are based on chromogenic calix[4]arene derivatives. The optode membranes were studied using UV/Vis absorption spectroscopy measurements. The sensitivity of the optode has been tested for Pb2+, Cd2+, Mg2+ and Eu3+ ions at pH 6.8. The results showed a good selectivity response towards Eu3+. Low selectivity coefficients were observed for Cd2+ and Mg2+ where Pb2+ can be considered as interfering ions. The characteristics of this optode such as response time, regeneration, reproducibility and lifetime are discussed. [Copyright &y& Elsevier]

In the great expansion of the social networking activity, young people are the main users whose choices have vast influence. This study uses the flow theory to gauge the impact of Facebook usage on Tunisian students' achievements, with the presumption that the high usage level might reduce students' scholar achievements. The research design suggests that this impact would vary among students with different interests for the university and multitasking capabilities. Facebook usage would develop students' satisfaction with friends and family, which could enhance their academic performance. Analyses from 161 Tunisian students show that Facebook usage does not affect significantly students' academic performance and their satisfaction with the family, whereas it decreases their actual satisfaction with friends. Yet, a high level of satisfaction of the student with his family continues to enhance his academic performance. Overall, though, Facebook usage appears to do not have a significant effect on undergraduate students' academic performance. However, this interdependency is significantly moderated by the student's interest for the university and his multitasking capabilities. Students with multitasking skills and students with initial interest for the university might experience a positive effect of Facebook usage on their studies, as they keep control over their activity and make it a beneficial leisure activity. However, students who do not have these characteristics tend to not have any significant effect. Results help to understand the psychological attitude and consequent behavior of the youths on this platform. Implications, limitations, and further research directions are offered. [ABSTRACT FROM AUTHOR]

The essential oils of fifteen Eucalyptus species harvested from the Jbel Abderrahman and Korbous arboreta (North East Tunisia) were screened for their antibacterial activities by the agar disc diffusion method. Eighteen major components as identified by GC/FID and GC/MS were selected for a study of the chemical and biological activity variability. The main one was 1,8-cineole, followed by spathulenol, trans-pinocarveol, α-pinene, p-cymene, globulol, cryptone, β-phellandrene, viridiflorol, borneol, limonene and isospathulenol. The chemical principal component analysis identified five species groups and subgroups, where each group constituted a chemotype, however that of the values of zone diameter of the inhibition (zdi) identified six groups of Eucalyptus oils, characterized by their antibacterial inhibition ability. The strongest activity was shown by E. platypus oil against Enterococcus faecalis and by E. lamannii oil against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. A correlation between the levels of some major components and the antibacterial activities was observed. [ABSTRACT FROM AUTHOR]

Abstract: Using the analysis of dinoflagellate cysts in three deep-sea sediments cores situated in the Sicilian-Tunisian Strait, in the Gulf of Lions and in the Alboran Sea, we reconstruct the paleoenvironmental changes that took place during the last glacial-interglacial transition in the western Mediterranean Sea. The development of the warm microflora Impagidinium aculeatum and especially Spiniferites mirabilis appears to be an important proxy for recognizing warm periods as the Bölling/Alleröd and the Early Holocene. Bitectatodinium tepikiense, Spiniferites elongatus and Nematosphaeropsis labyrinthus mark the end of the Heinrich event 1 and the Younger Dryas. This cold microfloral association confirms the drastic climate changes in the western Mediterranean Sea synchronous to the dry and cold climate which occurred in the South European margin. The dinocyst N. labyrinthus shows high percentages in all studied regions during the Younger Dryas. Its distribution reveals a significant increase from the South to the North of this basin during this cold brief event. Thus, we note that this species can be considered as a new eco-stratigraphical tracer of the Younger Dryas in the western Mediterranean Sea. [Copyright &y& Elsevier]

Abstract: A studies of a tetrakis(phenylazo)calix[4]arene derivative have been developed for cation recognition. The complexation properties of this ligand towards transition metal ions have been investigated by UV–Visible and fluorescence spectroscopies. It has been found that the ligand has remarkable complexation ability for transition metal Ni2+, Co2+, Hg2+, heavy metal ions Al3+ and Pb2+ with an exceptional high affinity for the lanthanide Eu3+ ion. The stoichiometric ratio of the complexation between the ionophore and Eu3+ ions in acetonitrile solution has been determined by applying the molar ratio method. The complexes formed are ML2 and ML in neutral and in basic medium respectively. The recognition properties between the thin film and the ions have also been studied. The complexation properties of the ligand with Eu3+ ion has been confirmed by fluorescence spectroscopy. [Copyright &y& Elsevier]

Abstract: In this work, we report the impedance spectroscopic investigation of the effect of the thin film type on the selectivity of gold/azo-calix[4]arene electrodes. For this purpose, two C1 and C3 azo-calix[4]arene derivative molecules, used as thin films, are deposited by spin-coating process on the gold surface. These thin films were first studied using contact angle measurements. This revealed a less hydrophobic character for C3 thin film, which has been attributed to the presence of hydroxyl groups at the lower rim. The sensitivity study, by Electrochemical Impedance Spectroscopy (EIS), towards Cu2+ and Eu3+ cations, has showed that the C3 thin film is more sensitive and selective towards Eu3+ than C1. This best performance is due to the presence of two ester groups acting as clips and leading to more complexation stability. The EIS results were modeled by an appropriate equivalent circuit for the aim of elucidating electrical properties of thin films. This modeling has exposed that C3 thin film presents lower ionic conductivity and limited diffusion phenomenon at the interface. [Copyright &y& Elsevier]

Abstract: Due to their recognition properties and efficiency for the detection of toxic metals, calixarenes have already found applications in the design of chemical sensors based on using an electrochemical transduction. In this study, a new chromogenic azo-calix[4]arene derivative was deposited on gold electrode by spin coating to develop a new electrochemical sensor. Adhesion and morphological properties of the membrane have been firstly developed using contact angle measurements and scanning electronic microscopy (SEM) respectively. Electrochemical impedance spectroscopy (EIS) is used to study the response of the calixarenes membrane in contact with aqueous solutions of various metallic cations. The impedance behavior of the structures has been modeled by an equivalent circuit using the Z-View software. This technique has shown a selective response of this membrane towards Hg2+, Ni2+ and Eu3+. The differences in selectivity are found to be represented by variations in the resistance of the membrane (R m) and in the charge transfer resistance (R ct) of the interface. Variation of CPE1 and CPE2 have been also investigated which were correlated to the porosity of the film and the exchange of the charge between the substrate and the electrolyte respectively. [Copyright &y& Elsevier]

Chitinases have been successfully used in combination with Bacillus thuringiensis delta-endotoxins forming crystals in order to enhance their insecticidal activities. In this context, we opted for promoting the chitinase integration into these crystals. Thus, we engineered, for the first time, a fusion protein (CDF) consisting of the chitinase Chi255 and the carboxy-terminal half of Cry1Ac, both from B. thuringiensis subsp. kurstaki. The constructed transcriptional fusion ( chi255Δsp- CTcry1Ac) was cloned into a shuttle vector ( Escherichia coli/ B. thuringiensis) downstream the sporulation-dependent promoters BtI-BtII and upstream the cry1Ac transcription terminator. The resulting plasmid, named pF, was transferred by electroporation to crystalliferous B. thuringiensis strain BNS3 and acrystalliferous strain BNS3Cry−. The functionality of the chimerical chitinase was demonstrated by an improvement of the relative chitinolytic activity of the recombinant strain BNS3/pF by 2.5 folds. Western blot analyses showed that, despite of the instability of CDF when expressed in the acrystalliferous strain, the C-terminal half of Cry1Ac succeeded to allow the integration of the chimerical chitinase into the crystal of BNS3. The recombinant strain BNS3/pF (LC = 144.06 μg g) was 1.5 times more active against Ephestia kuehniella larvae than the wild strain (LC = 212.10 μg g). [ABSTRACT FROM AUTHOR]

Abstract: A high resolution micropalaeontological study of the core MD 04-2797 CQ recovered in the Sicilian–Tunisian Strait provides insights into the paleoclimatic history of the Mediterranean Sea at the transition between the western and eastern basin over the last 30ka. Using the analysis of dinoflagellate cyst and planktonic foraminiferal assemblages, we reconstruct the paleoenvironmental changes that took place in this region. High abundances of cold temperate dinocyst species (Nematosphaeropsis labyrinthus, Spiniferites elongatus, Bitectatodinium tepikiense) and the polar planktonic foraminifera Neogloboquadrina pachyderma (left coiling) reveal three major cooling events synchronous with North Atlantic Henrich events 1 and 2 (H1 and H2) and the European and North Atlantic Younger Dryas event. During the Holocene, the presence of warm dinocyst species (Spiniferites mirabilis and Impagidinium aculeatum) and planktonic foraminifera (Globorotalia inflata and Globigerinoides ruber), reflects a significant increase of sea surface temperatures in the western Mediterranean basin, but a full warming was not recorded until 1500years after the onset of the Holocene. Moreover, our results show that the Holocene was interrupted by at least four brief cooling events at ~9.2ka, ~8ka, ~7ka and ~2.2ka cal. BP, which may be correlated to climatic events recorded in Greenland ice cores and in the Atlantic Ocean. [Copyright &y& Elsevier]

BLB1 is a new Bacillus thuringiensis kurstaki strain, isolated from a Tunisian soil sample. Assay of toxicity of BLB1 crystal proteins resulted in an LC50 of 70.32 ng of toxin per mg of flour against third instar Ephestia kuehniella with confidence limits of (31.6–109.04 ng). This LC50 is less than that of the commercial strains HD1 used as a reference. The characterization of this strain by scanning transmission electron microscopy, analysis of its cry genes content by PCR-sequencing, and analysis of its δ-endotoxin patterns demonstrate that it belongs to the same subgroup than HD1, but ruled out the involvement of cry gene content or protoxin activation in the hypertoxicity of this strain. Taking into account the δ-endotoxin/spore ratio for each strain, and by allowing the estimation of the production level per spore, it might be concluded that BLB1 production is the highest, when compared with that of HD1. On the basis of its toxicity, BLB1 could be considered as a strain of great interest and would allow the production of quantities of bioinsecticides at low cost. [ABSTRACT FROM AUTHOR]

Abstract: Electrical measurements have been performed on spin-coated azo-calix[4]arene derivative on pre-cleaned indium thin oxide (ITO) substrates using current versus voltage, capacitance versus voltage and impedance spectroscopy measurements. The nature of trap states in single layer ITO/azo-calix[4]arene derivative/Al organic diodes has also been investigated. The energy band gap of the thin film containing calixarene derivative has been measured by UV–Vis absorption spectroscopy and is about 2.77eV. The current–voltage characteristics have shown ohmic behavior at low voltages. At high applied bias the I–V characteristics can be successfully modeled by space-charge limited current (SCLC) theory. The impedance dependence of bias and frequency is discussed in terms of the presence of a depletion layer in the bulk. The device is accurately modeled, in a range of frequency between 100Hz and 1MHz, as a single parallel resistor and capacitor network placed in series with a resistance. Their values deduced from fitting experimental data to the model have given a dielectric relaxation time in the ms range and an exponential trap distribution. [Copyright &y& Elsevier]

Abstract: A sensing material based on calix[4]arene molecules (Azo-C[4]) dispersed in a conjugated polymer (MEHPPV) is deposited by spin coating onto a transparent conducting substrate (ITO) to fabricate new chemical sensors. The electrochemical properties of the sensor are investigated by impedance spectroscopy. Transfer and ion diffusion processes of metal cations (Cu2+, Eu3+) in the Azo-C[4]-MEHPPV membranes are studied. The calixarene molecule behaviour into the polymer membranes is characterised by impedance spectroscopy showing the cation complexation by both, Azo-calix[4]arene and MEHPPV, components of the membrane. The differences in selectivity are found to be represented by variations in the bulk resistance of the membrane (R m) and in the charge transfer resistance (R tc) of the interface. The impedance behaviour of the Azo-C[4]-MEHPPV electrodes is modelled by an equivalent electrical circuit. Optical excitation tests of these membranes show that the sensing activity of the calixarene molecules entrapped in the polymer matrix is preserved. [Copyright &y& Elsevier]

Abstract: Three single-chain variable fragment (scFv) antibodies recognizing the nuclear inclusion a (NIa) and capsid proteins of potato virus Y were obtained from two mouse derived hybridoma clones secreting, respectively, an anti-NIa (22-1) and an anti-coat protein (136-13) monoclonal antibodies. The first monoclonal antibody was able to inhibit in vitro the PVY polyprotein cleavage by blocking the NIa protease activity. The amplified scFv cDNAs were first inserted into the TOPO vector and then sequenced. Several recombinant E. coli clones carrying the accurate scFv sequences were selected and the corresponding cDNAs were subcloned in pHEN phagemid and transferred in E. coli strain. The expressed scFv fragments showed an antibody activity that recognized the viral target proteins in infected tissues. Their activity was comparable to the parental monoclonal antibodies. [Copyright &y& Elsevier]

Abstract: New chromogenic calix[4]arene derivatives proved many applications in optical and electrical fields. Organic diodes formed by sandwiching azo-calix[4]arene layers between indium-thin oxide (ITO) and (Al) contacts have been elaborated and measured. In this paper, studies of devices by current–voltage characteristics I(V) and electrical impedance spectroscopy measurements in a wide frequency range have been reported. The electrical characteristics follow a space charge limited conduction behaviour (SCLC). Therefore, the Cole–Cole plots were modelled by an equivalent circuit. Relaxation processes have been identified too from the impedance spectroscopy. The optical excitation of the organic structure revealed enhancement in electrical properties. [Copyright &y& Elsevier]

Abstract: Due to their potential applicability as selective receptors in electrochemical and/or optical sensors (optodes) a new family of chromogenic calix[4]arenes derivatives were investigated. The complexing properties of these molecules towards metallic cations and lanthanides and the photophysical properties of the formed compounds in acetonitrile solution have been studied by UV/Vis spectroscopy. The molar ratio method revealed that the stoichiometry of calix[4]arenes 1a and 1b to Eu(III) in the complex is 1:1. The stability constants of the complexes have been determined. [Copyright &y& Elsevier]

Many investigations have been achieved on molecular materials according to their possible application as sensors and electronic devices. Calix[n]arenes were receptor molecules for a wide variety of cations and organic molecules. This propriety was attributed to the phenolic unit that allow the synthesis of molecules with different size and conformations. In this work, we present experimental results of Electrolyte–Insulator–Semiconductor (EIS) devices coated by layers of p-tert-butylcalix[n]arenes (n=8,9,11,12). The sensitivity of the layers towards specific cations was investigated by electrochemical capacitance measurement. Spin coating and evaporation methods of deposition were compared. The response curves of the devices were fitted using the site-binding model which allows to determine the surface ligand number and the complexation constant pK values. [Copyright &y& Elsevier]

Large eddy simulation (LES) of fully developed, incompressible turbulent channel flows are presented for stationary and rotating pipes. A dynamic model and the Smagorinsky model were used and compared with DNS results. The 3-D governing equations written in a cylindrical coordinate system were solved by a finite difference method, second-order accurate in space and in time. The features of the flows at two Reynolds numbers and for various rotation speeds are discussed and compared to available data of literature. [Copyright &y& Elsevier]

To determine if additional agar plates could allow earlier detection of anaerobes in spinal surgical site infections (SSIs), we performed a prospective study (November 2017‐January 2019) of patients with early spinal SSIs. In addition to routine 14‐day cultures, surgical samples were inoculated onto three additional plates (CDC anaerobe agar with 5% sheep blood [CDC], CDC anaerobe laked sheep blood agar with kanamycin/vancomycin [BBL], and Bacteroides bile esculin [BBE] agar with amikacin (BD, USA)) incubated under anaerobic conditions (72 h, 37°C). The primary endpoint was detection of anaerobes by these methods, as compared to routine culture. Anaerobes were identified in 7/61 patients (11%) using the routine procedure and in one extra case with additional plates (overall detection rate 8/61, 13%). Sensitivity was greater for the CDC plate than for the BBL and BBE plates. When routine culture was positive, the CDC plate was always positive, and in three cases showed at least one additional anaerobe. Using additional agar plates, anaerobes were identified in early spinal SSI in 13% of patients. Within 3 days, CDC agar plate enabled detection of anaerobes in one extra case and at least one additional anaerobe in three other cases, compared to routine 14‐day culture. [ABSTRACT FROM AUTHOR]