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Converting biomass waste into high-value products presents a challenging task in the environmental field. Growth of graphene from solid-state precursors is cost-effective and is becoming a hot research topic. However, the underlying mechanisms are as yet unclear. In this work, we report a novel method for directly growing adlayer-free large area graphene from cellulose acetate, the main component of cigarette filter waste. The evolution of cellulose acetate to reduced graphene oxide and finally to graphene is shown in this work for the first time. The effect of various growth parameters, hydrogen concentration and Cu grain boundaries on the size and qualities of the monolayer graphene domains is clarified. Finally, the mechanism for the growth of graphene from a solid-state precursor is proposed. The field-effect-transistor fabricated from transferred monolayer graphene demonstrated high electron and hole mobilities ∼1500 cm2/(V·s). This work presents a new opportunity for converting biomass waste into high-value graphene products.

Worldwide NH3 production reached 0.18 Gton in 2019, and 1–2% of the global CO2 emissions are due to large-scale NH3 synthesis (1 billion tons of CO2 / year). A catalyst for ammonia synthesis has been obtained by pyrolysis of iron phthalocyanine (FePc) precursor under N2, followed by impregnation with alkali metals (Na, Li, K, and Cs) and H2 treatment. Characterization (XPS, XRD, HR-TEM, ICP-OES, TGA, CHNS analysis, and BET) revealed nano-sized core–shell structures formed during H2 treatment, with Fe in the core and promoters (“Cs2O” and “K2O”) with carbon on the shell. The alkali metals partially inhibit the methanation process of carbon. These Fe NPs were found to be very active and stable catalysts, as compared to the commercial iron-based catalyst KM1 (Haldor-Topsoe). Activities of promoted catalysts follow the order: K > Cs > Na ~ Li, with more than 6% of NH3 at 400 °C and 7 MPa, and contact time (WHSV) of 12000 ml g−1 h−1 with K. The apparent activation energy was found to be 31 kJ mol−1 and 34 kJ mol−1 for 3-K-FePc700 and 10-Cs-FePc700 suggesting the facile activation of N2 on the catalysts surface. DFT-based predicted atomic and electronic structures reveal a similarity in the partial charge distribution on surface Fe species with K or Cs. Surprisingly the main effect of alkali is related to the geometrical repartition of alkali, leading to a larger number of exposed iron atoms, active sites, in the case of K than Cs. The alkali (present as metal oxide) leaves at medium coverage of the surface some exposed Fe(0) for N2 non-dissociative chemisorption (end-on type). The free energy profile demonstrates that the thermodynamic stability of the reaction intermediates for nitrogen reduction reaction (NRR) increases with pressure indicating better feasibility of the reaction at higher pressures.

High-performance chemiresistor gas sensor made of sulfide porous GaN decorated with Pt nanoparticles, which shows tunable sensor response and enhanced sensitivity. The fabricated gas sensors show detection of H2 down to 30 ppm at 23 °C after sulfide treatment and Pt decorated porous GaN. The response time and recovery time were equal to 47 s and 113 s, respectively. Density functional theory simulations were used to support the detection mechanism based on sulfide treatment. Adsorption energy calculations showed that H adsorption energy is lowered by the simultaneous presence of S and Pt on the GaN (0001) surface. The density of states (DOS) calculations revealed possibility of bond strengthening when Pt and S is adsorbed on GaN surface along with H, arising from the hybridization of d and p orbitals of Pt and S with that of H 1s orbitals.

Resume L’ecstasy est la drogue de synthese la plus consommee par les jeunes adultes dans les soirees festives. Cette drogue agit en augmentant la neurotransmission adrenergique et serotoninergique, il en resulte des symptomes cardio-vasculaires et neuropsychiatriques qui peuvent menacer le pronostic vital des jeunes consommateurs. Cet article presente le cas d’un jeune homme de 27 ans qui decede a la suite de l’ingestion de deux comprimes surdoses en ecstasy lors d’une soiree festive. A l’admission, le patient etait en etat d’extreme agitation, il presentait une tachycardie a 150 bat/min et une hyperthermie a 40,5 °C. Il presentait une insuffisante renale aigue avec creatininemie a 310 µmol/L et uremie a 88,7 mmol/L. Une acidose metabolique lactique decompensee, une rabdomyolyse avec un taux de creatine phospho-kinase (CPK) a 752 mmol/L et une lactate deshydrogenase (LDH) a 3 044 mmol/L. Les enzymes hepatiques s’elevaient a treize fois la normale. La troponine s’elevait a 10 875 ng/L. Une coagulation intraveineuse disseminee s’est installee avec un taux de prothrombine (TP) a 10 %, DDimeres a 12 000 µg/mL, plaquettes a 41 000 elements/mm3, le fibrinogene et le facteur V etaient indetectables. Le patient decede apres quelques heures par defaillances multiviscerales.

This work was supported by Huawei Grant RGC/3/3513 and KAUST Baseline BAS/1/1375. The authors acknowledge the support from Cao Zhen for the DFT calculation.

In the digitization air, it is very important to detect and analyze the related topics to some discussions, occurred in social media or to label some visited web pages or documents. This information could be very helpful to the process of personalization as well as user satisfaction. There are various and different methods that study and deal with a huge data to provide insights into user behaviors. In this paper, we propose a filtering process that enhances topic detection and labelling. The latter aims to compact the result delivered by inferential algorithms such as Latent Dirichlet Allocation and Dirichlet Mixture Model. Our filtering process relies on words dependency on each contextual use for delivering high correlated label. Indeed, we use Word2vec as well as N-grams to eliminate non-significant words in each topic. We also use Hellinger distance to aggregate redundant words to the appropriate topic. Besides, we eliminate the non-reliable topics according to some metric. We associate this proposal to different topic-modeling algorithms. Experiments demonstrate the effectiveness of the made association between inferential model and our filtering process compared to the state of the art. We also use different textual data to validate our proposal.

Patulin (PAT) is a common mycotoxin in fruit products, especially in apples and apple-based products. The European Commission has set maximum levels for PAT in food. Nevertheless, worrying PAT levels were recently recorded in diverse foods across the world. Therefore, a worldwide follow-up of PAT-levels in foods should be considered. Because of PAT's high probability in food products, the toxicological implications for humans need to be addressed as well. Recent studies proved adverse health effects of PAT, such as hepatotoxicity, gastrointestinal alterations and inmunotoxicity. In comparison to the toxicity of other mycotoxins such as ochratoxin A, PAT's immunotoxicity can be even more outspoken destructive. In addition, PAT is a low-molecular-weight and highly polar molecule, resulting in many analytical challenges for its detection. As the analytical techniques are continuously improving, PAT determination in multi-mycotoxin analysis has advanced using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) during the last year. Finally, the presence and toxicity of PAT requires a biomarker method to assess its exposure among the population. To date, however, there is no information regarding PAT biomarkers in biological samples. This short review highlights the PAT-occurrence profile, toxicological discoveries and analytical challenges of 2014 until to date.

We demonstrate a novel strategy to enhance sulfur loading and rate performance for Li–S battery by synchronously coupling a nanostructured cathode with an antifouling separator via a facile electrostatic self-assembly approach. The assembly of two dimensional (2D) MXene and positively charged 1D CNT-Polyethyleneimine was observed to controllably address the key issues of sluggish ionic transport, and produce an integrate cathode with dynamic crosslinking network. Moreover, an antifouling separator is proposed by this strategy for the first time, which features well-organized inter-lamellar porosity, dual polarity and high conductivity. The antifouling separator is found to play a pivotal role in: 1) low-order polysulfide activation, 2) high rate cyclability, and 3) Li dendrites inhibition. Our integrated design realizes a long-term capacity of 980 mAh g−1 at 5 mA cm−2 over 500 cycles (sulfur loading: 2.6 mg cm−2). Furthermore, a flexible self-assembled cathode with high loading (5.8 mg cm−2) and superb mechanical strength (13 MPa), demonstrates an appealing areal capacity of 7.1 mAh cm−2 and rate performance at nearly 10 mA cm−2.

Reduced graphene oxide (rGO) has inherited the outstanding electronic, optical, thermal and mechanical properties of graphene to a large extent, while maintaining sufficient chemically active sites. Therefore, it has attracted a great deal of research attention in the fields of energy storage, electronics, photonics, catalysis, environmental engineering, etc. Currently, the most popular way to prepare rGO is to reduce graphene oxide, which is obtained by modified Hummer methods using tedious treatments in a harsh environment, to rGO flakes. Industrial applications demand advanced preparation methods that can mass produce highly uniform rGO sheets on arbitrary substrates. In this work, a one-step growth process is introduced that utilizes cellulose acetate as a precursor, without any catalysts, to produce uniform ultrathin rGO films on various substrates and free-standing rGO powders. Systematic spectroscopic and microscopic studies on the resulting rGO are performed. Prototypes of electronic and optoelectronic devices, such as field effect transistors (FETs), photodetectors, and humidity sensors, are fabricated and tested, demonstrating the intriguing applications of our rGO materials across a wide range of fields.

In this work, we report a theoretical investigation of the structural, electronic and optical properties of InP1−xBix alloys. The study has been carried out by varying up the fraction x from 0 to 0.375. The calculations are performed using the density functional theory (DFT). The full potential linearized augmented plane wave (FPLAPW) scheme, as implemented in Wien2k package, is employed. The modified Becke-Johson potential with local density approximation (mBJLDA), which combines the Becke-Johson exchange potential with the local density approximation correlation potential, is used to evaluate the alloys band structure. We have studied the effect of bismuth composition on the structural and optoelectronic proprieties and found that lattice parameter of the compound increases with the bismuth composition which is in good agreement with Vegard’s law. A band gap reduction of the order 36 meV/%Bi with the Bi composition is observed giving rise to a semi-metallic behaviour beyond a composition about 47%. The effective masses of the binary compound InP and InP1−xBix alloys obtained, by our calculations, are in good agreement with the experimental results. Furthermore, the effects of the bismuth concentration on the dielectric function of the alloys is elucidated, suggesting that dopage of bismuth tunes the electronic and optical properties of the InP matrix. In addition, the calculated low value of the reflectivity in the visible and UV region of the InPBi alloys, together with the consistent behavior of the band gap and the reflective index variations with the composition of bismuth overall experimental results, shed light on the candidacy of InP1−xBix alloys as potential material for optoelectronic applications.

We propose hydroxyl-functionalized polytriazole as a precursor for the preparation of highly crosslinked membranes and carbon molecular sieves (CMS) for gas separation. We studied the effect of the treatment temperature on the chemical structure and gas separation properties. A progressing crosslinking structure was formed when polytriazole films were treated in the range of 300–400 °C. Above 425 °C, CMSs with multi-layered nitrogen-graphene-like structures were obtained. The CO2 permeability increased by increasing the temperature, while the CO2/CH4 selectivity was maintained. Permeability increases up to 37-fold compared to the untreated polymer film were obtained, aligned with a CO2/CH4 selectivity of 75. The single-gas CO2 permeability vs. CO2/CH4 selectivity data obtained for films treated at 475 and 550 °C are among the highest reported in the literature. Moreover, the mixed gas performance of these membranes is far above previously reported CO2/CH4 data plotted as mixed-gas trade-off curves, demonstrating the potential of polytriazole materials for these applications.

The mechanism of formation of Pt@SiO2 as a model of core-shell nanoparticles via water-in-oil reverse microemulsions was studied in detail. By controlling the time of growth of Pt precursors, Pt(OH)(x), after hydrolysis in NH3 aq. before adding SiO2 precursor (TEOS), Pt nanoparticles with a narrow size distribution were produced, from ultrafine metal nanoparticles (

Forensic investigation performed on people suspected to be drug abusers covering all Tunisian cities was conducted by monitoring an epidemiological study of human urine samples surveying positive rates of consumption for drugs of abuse. The forensic investigations were conducted on a total of 28,298 arrested individuals suspected to be drug addicts during five years (January 2010-December 2015). An immunoassay screening tests to detect elevated levels of drugs classes in urine samples was performed. These screening assays provide a preliminary qualitative test result. Only positives urine specimens were analyzed with GC-MS for confirmation. Except for cannabis, the results showed insignificant number of positive cases for cocaine, ecstasy (MDMA) and amphetamine consumptions (

Summary Hydrolytically stable adsorbents, with notable water uptake, are of prime importance and offer great potential for many water-adsorption-related applications. Nevertheless, deliberate construction of tunable porous solids with high porosity and high stability remains challenging. Here, we present the successful deployment of reticular chemistry to address this demand: we constructed Cr- soc -MOF-1, a chemically and hydrolytically stable chromium-based metal-organic framework (MOF) with underlying soc topology. Prominently, Cr- soc -MOF-1 offers the requisite thermal and chemical stability concomitant with unique adsorption properties, namely extraordinary high porosity (apparent surface area of 4,549 m 2 /g) affording a water vapor uptake of 1.95 g/g at 70% relative humidity. This exceptional water uptake is maintained over more than 100 adsorption-desorption cycles. Markedly, the adsorbed water can be fully desorbed by just the simple reduction of the relative humidity at 25°C. Cr- soc -MOF-1 offers great potential for use in applications pertaining to water vapor control in enclosed and confined spaces and dehumidification.

Summary Conventional methods for diagnosis of invasive aspergillosis (IA) lack sensitivity and specificity. Serological methods still have many cases of cross-reactivity. However, molecular techniques seem to arise as a rapid approach, specific and direct that could be used in the diagnosis of IA. In this study, we analyzed 88 serum samples from patients of having IA using GM-ELISA test, nested PCR with primers for the rRNA 18S of Aspergillus genus and real time PCR specific for A. fumigatus . Among the 88 samples, 64 of them had positive GM titers and 23 had positive nested PCRs; 18 of the 23 PCR-positive samples were also GM-positive. On the other hand, 18 samples were detected positive by reel time PCR; 13 positive samples were also detecting positive by nested PCR. QPCR revealed 26 % of the patients with IA, while nested PCR and galactomannan ELISA revealed respectively 34 % and 94 % of the patients with IA. Probable IA was diagnosed in 18 and possible IA was diagnosed in 6 episodes. Forty-four episodes were defined as not having IA. The positive and negative predictive values were respectively 100 %, and 88 % for QPCR, 100 % and 97 % for nested PCR, and 28 % and 60 % for GM test. These results suggesting that combined use of methods might improve the diagnosis of IA.

The major challenge in membrane filtration is fouling which reduces the membrane performance. Fouling is mainly due to the adhesion of foulants on the membrane surfaces. In this work, we studied the fouling behavior of polystyrene- b -poly(4-vinylpyridine) (PS- b -P4VP) isoporous membrane and the mussel inspired polydopamine/ L -cysteine isoporous zwitterionic membrane. Polystyrene- b -poly(4-vinylpyridine) (PS- b -P4VP) isoporous membranes were fabricated via self-assembly and non-solvent induced phase separation method. Subsequently, the isoporous membrane was modified by a mild mussel-inspired polydopamine (PDA) coating; the isoporous surface structure and the water flux was retained. Zwitterionic L -cysteine was further anchored on the PDA coated membranes via Michael addition reaction at pH 7 and 50 °C to alleviate their antifouling ability with foulants solution. The membranes were thoroughly characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and zeta potential measurements. Contact angle and dynamic scanning calorimetry (DSC) measurements were carried out to examine the hydrophilicity. The pH-responsive behavior of the modified membrane remains unchanged and antifouling ability after PDA/ L -cysteine functionalization was improved. The modified and unmodified isoporous membranes were tested using humic acid and natural organic matter model solutions at 0.5 bar feed pressure.

There exists a strong demand to replace expensive noble metal catalysts with efficient and earth-abundant catalysts for hydrogen evolution reaction (HER). Recently the Co- and Mo-based sulfides such as CoS2, Co9S8, and MoSx have been considered as several promising HER candidates. Here, a highly active and stable hybrid electrocatalyst 3D flower-like hierarchical Co9S8 nanosheets incorporated with MoSx has been developed via a one-step sulfurization method. Since the amounts of Co9S8 and MoSx are easily adjustable, we verify that small amounts of MoSx promotes the HER activity of Co9S8, and vise versa. In other words, we validate that symmetric synergy for HER in the Co- and Mo-based sulfide hybrid catalysts, a long-standing question requiring clear experimental proofs. Meanwhile, the best electrocatalyst Co9S8-30@MoSx/CC in this study exhibits excellent HER performance with an overpotential of −98 mV at −10 mA/cm2, a small Tafel slope of 64.8 mV/dec, and prominent electrochemical stability.

Strategies to synthesize reduced graphene oxide (rGO) abound but, in most studies, research teams select one particular oxidation-reduction method without providing a methodic reasoning for doing so. Herein, it is analyzed how diverse oxidation-reduction strategies commonly used can result in considerable performance differences of rGO for supercapacitor applications. Depending on the graphite oxidation method followed, the surface chemistry analysis of the products confirms that there is a marked disparity in the degree of oxidation and the nature of the oxygen functional groups present. Subsequent reduction of the oxidized graphite (using three different methods) showed that the maximum specific capacitance of rGOs produced from the classical Hummers' method was 128 F g−1 whereas an analogous material obtained from an improved Hummers' method reached ∼274 F g−1 (both via an hydrothermal reduction route). Besides showing that the improved oxidation method results in superior capacitance performance, explained by the higher number of structural defects allied to a surface chemistry where residual hydroxyl and epoxy functional groups predominate, this study highlights the need to rationalize the oxidation-reduction strategies followed when investigating applications of rGO materials.

Personalized system represents nowadays a key factor to attract user and to guide special end users concerns. All systems that include interaction with end users are seeking to improve this factor, particularly, Personalized systems that use Multi-Agent System (PMAS), characterized by agents collaboration and parallel execution of tasks, as a tool to implement the personalization. However, assessing this kind of personalized system is complicated and generally restrained to empirical assessment. In this context, our purpose is to process the assessment of PMAS through the confrontation between the system to be evaluated and a referential one. In this paper, we deal with the web environment. We describe first our referential system, then, we focus on the prediction layer of this system. We demonstrate the use of Convolutional Long Short-Term Memory (ConvLSTM), a machine learning approach, to treat the semantic reasoning of the end users.