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Optical Spatial mode-division multiplexing that exploits the new few-mode fiber (FMF) technology is a promoted solution for the new optical communication systems. We work on the multilayers method of designing the new optical communication systems FMF. These systems suffer essentially from differential mode delay. In this article, we implement the multilayers method of designing an arbitrary fiber profiles with our own Matlab code and we proposed a fiber profile design with a full control of differential mode delay regions in the C-and L-bands, for six linearly polarized modes circulating in FMF with the cited method.

The globalization of markets, the intensity of competition, and the evolution of technology have led to the appearance of new organizational forms based on projects. Faced with these changes, companies are forced to review and rethink their human resources management system to better adapt to the project environment. Career development is an essential factor in human resource management. This study aimed to understand the role of career development in the relationship between project-based organization (PBO) and human resources management (HRM). To this end, we conducted a qualitative study based on 31 interviews among Tunisian project managers. The results show that interviewees often lack such career development opportunities because of the temporary nature of their jobs. Project managers have to be responsible and proactive in developing their career path by maintaining and developing their skills.Keywords: Career development, project-based organization, human resource management, skills, qualitative research, Tunisia.JEL Classifications: J24, M12DOI: https://doi.org/10.32479/irmm.11416

SMARCA4-deficient thoracic sarcoma (SMARCA4-DTS) is a recently identified aggressive subtype of sarcoma. We present the case of a 44-year-old man who underwent a surgery for a perforated small intestine. Compued tomography scan revealed a tissular mediastino–pulmonary mass.Histopathological examination of the intestinal mass shown a malignant tumour with a typical epithelioid and rhabdoid cells, numerous mitoses and large necrosis. A large panel of immunohistochemistry revealed loss of SMARCA4 and SMARCA2 and allowed the diagnosis of SMARCA4-DTS. It is important to consider SMARCA4-deficient thoracic sarcoma in the differential diagnosis of tumours showing suggestive morphologic features in patients of all ages, especially in the case of metastasis associated with thoracic mass.

Since the 1980s, the project has become an essential management approach for contemporary companies that require profound organizational transformations, hence the need for more in-depth studies on human resources development in this new environment. The present work aimed to recognize the different challenges of the training policy in the project environment. To this end, we conducted 31 semi-structured interviews with Tunisian project managers. The results showed that the training policy is a conducive context for skills development in the project environment. Project-based organizations are called upon to promote their employees’ skills through training programs encompassing mainly two kinds of skills: interpersonal and technical. The results also revealed that the temporary and unstable nature of the projects leaves little room for training due to time pressure, lack of budget, and work overload.

Vanadium dioxide (VO2) has emerged as a promising micro-actuator material for its large amplitude and high work density across the transition between the insulating (M1 and M2) and metallic (R) phase. Even though M2–R transition offers about 70% higher transformation stress than M1–R structural phase transition, the application of the M2 phase in the micro-actuators is hindered by the fact that previously, M2 phase can only stay stable under tensile stress. In this work, we propose and verify that by synthesizing the VO2 nanowires under optimized oxygen-rich conditions, stoichiometry change can be introduced into the nanowires (NWs) which in turn yield a large number free-standing single-crystalline M2-phase NWs stable at room temperature. In addition, we demonstrate that the output stress of the M2-phase NWs is about 65% higher than that of the M1-phase NWs during their transition to R phase, quite close to the theoretical prediction. Our findings open new avenues towards enhancing the performance of VO2-based actuators by using M2–R transition.

Recent advancements in gallium oxide (Ga2O3)-based heterostructures have allowed optoelectronic devices to be used extensively in the fields of power electronics and deep-ultraviolet photodetection. While most previous research has involved realizing single-crystalline Ga2O3 layers on native substrates for high conductivity and visible-light transparency, presented and investigated herein is a single-crystalline β-Ga2O3 layer grown on an α-Al2O3 substrate through an interfacial γ-In2O3 layer. The single-crystalline transparent conductive oxide layer made of wafer-scalable γ-In2O3 provides high carrier transport, visible-light transparency, and antioxidation properties that are critical for realizing vertically oriented heterostructures for transparent oxide photonic platforms. Physical characterization based on X-ray diffraction and high-resolution transmission electron microscopy imaging confirms the single-crystalline nature of the grown films and the crystallographic orientation relationships among the monoclinic β-Ga2O3, cubic γ-In2O3, and trigonal α-Al2O3, while the elemental composition and sharp interfaces across the heterostructure are confirmed by Rutherford backscattering spectrometry. Furthermore, the energy-band offsets are determined by X-ray photoelectron spectroscopy at the β-Ga2O3/γ-In2O3 interface, elucidating a type-II heterojunction with conduction- and valence-band offsets of 0.16 and 1.38 eV, respectively. Based on the single-crystalline β-Ga2O3/γ-In2O3/α-Al2O3 all-oxide heterostructure, a vertically oriented DUV photodetector is fabricated that exhibits a high photoresponsivity of 94.3 A/W, an external quantum efficiency of 4.6 × 104%, and a specific detectivity of 3.09 × 1012 Jones at 250 nm. The present demonstration lays a strong foundation for and paves the way to future all-oxide-based transparent photonic platforms.

Solution-processed organic-inorganic hybrid perovskites have attracted attention as light-harvesting materials for solar cells and photonic applications. The present study focuses on cubic single crystals and microstructures of CH3NH3PbBr3 perovskite fabricated by a one-step solution-based self-assembly method. It is seen that, in addition to the nucleation from the precursor solution, crystallization occurs when the solution is supersaturated, followed by the formation of a small nucleus of CH3NH3PbBr3 that self-assembles into bigger hollow cubes. A three-dimensional (3D) fluorescence microscopy investigation of hollow cubes confirmed the formation of hollow plates on the bottom; then, the growth starts from the perimeter and propagates to the center of the cube. Furthermore, the growth in the (001) direction follows a layer-by-layer growth model to form a complete cube, confirmed by scanning electronic microscopy (SEM) observations. Two-dimensional (2D)-3D fluorescence microscopy and photoluminescence (PL) measurements confirm a peak emission at 535 nm. To get more insights into the structural and optical properties, density functional theory (DFT) simulations were conducted. The electronic and optical properties calculated by DFT are in agreement with the obtained experimental values. The density-of-state (DOS) calculations revealed that the valence band maximum (VBM) consists of states contributed by Br and Pb, which agrees with the X-ray photoelectron spectroscopy valence band (XPS VB) measurements.

The concept of competence has recently been a hot topic in science management, particularly human resource management. However, most of the studies conducted on this topic have mainly been theoretical. Thus, the present study aims to operationalize competence management through the construction and validation of a questionnaire intended for Tunisian project managers. To this end, a quantitative study is conducted among 156 respondents. The principal component analysis and Cronbach's alpha calculations were used to ensure the validity and reliability of the factor structures. The results of the factor analysis confirm the existence of a measurement scale of competence management that comprises five independent dimensions, namely recruitment, assessment, training, compensation, and career management. This study provides project managers with a measurement instrument that can be used to analyze competence management practices in their companies so that they can develop and enhance their employees’ skills.

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.

We acknowledge the use of KAUST Core Lab and KAUST Solar Center facilities. This work was supported by KAUST and the Office of Sponsored Research (OSR) under award no. OSR-2017-CRG-3380. F.G. is a Wallenberg Academy Fellow.

In recent years, the globalization of markets, the intensity of competition and the evolution of technology have forced companies to rationalize their management practices. Two main consequences arise: First, the emergence of new forms of organization, in particular project-based organization (PBO), denouncing the principles of scientific management. Second, the emergence of competence management has become an essential factor in the modernization of human resources management. This study aimed to understand how the relationship between PBO and competence management is effectively achieved. To this end, a qualitative research was conducted within Tunisian companies operating in different sectors of activity. The results show that recruitment and evaluation are two essential practices at the service of PBO and competence management. The results provide managers with a better understanding of the competence management in the PBOs.

In recent years, β-Ga2O3/NiO heterojunction diodes have been studied, but reports in the literature lack an investigation of an epitaxial growth process of high-quality single-crystalline β-Ga2O3/NiO thin films via electron microscopy analysis and the fabrication and characterization of an optoelectronic device based on the resulting heterojunction stack. This work investigates the thin-film growth of a heterostructure stack comprising n-type β-Ga2O3 and p-type cubic NiO layers grown consecutively on c-plane sapphire using pulsed laser deposition, as well as the fabrication of solar-blind ultraviolet-C photodetectors based on the resulting p-n junction heterodiodes. Several characterization techniques were employed to investigate the heterostructure, including X-ray crystallography, ion beam analysis, and high-resolution electron microscopy imaging. X-ray diffraction analysis confirmed the single-crystalline nature of the grown monoclinic and cubic (201) β-Ga2O3 and (111) NiO films, respectively, whereas electron microscopy analysis confirmed the sharp layer transitions and high interface qualities in the NiO/β-Ga2O3/sapphire double-heterostructure stack. The photodetectors exhibited a peak spectral responsivity of 415 mA/W at 7 V reverse-bias voltage for a 260 nm incident-light wavelength and 46.5 pW/μm2 illuminating power density. Furthermore, we also determined the band offset parameters at the thermodynamically stable heterointerface between NiO and β-Ga2O3 using high-resolution X-ray photoelectron spectroscopy. The valence and conduction band offsets values were found to be 1.15 ± 0.10 and 0.19 ± 0.10 eV, respectively, with a type-I energy band alignment.

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.

The direct hydrogenation of CO2 to methanol using hydrogen is regarded as a potential technology to reduce greenhouse gas emissions and the dependence on fossil fuels. For this technology to become...

Semiconductor quantum well structures have been critical to the development of modern photonics and solid-state optoelectronics. Quantum level tunable structures have introduced new transformative device applications and afforded a myriad of groundbreaking studies of fundamental quantum phenomena. However, noncolloidal, III–V compound quantum well structures are limited to traditional semiconductor materials fabricated by stringent epitaxial growth processes. This report introduces artificial multiple quantum wells (MQWs) built from CsPbBr3 perovskite materials using commonly available thermal evaporator systems. These perovskite-based MQWs are spatially aligned on a large-area substrate with multiple stacking and systematic control over well/barrier thicknesses, resulting in tunable optical properties and a carrier confinement effect. The fabricated CsPbBr3 artificial MQWs can be designed to display a variety of photoluminescence (PL) characteristics, such as a PL peak shift commensurate with the well/ba...

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.

Smart solar-blind UV-C band photodetectors suffer from low responsivity in a self-powered mode. Here, we address this issue by fabricating a novel enhanced solar-blind UV-C photodetector array based on solution-processed n-ZnO quantum dots (QDs) functionalized by p-CuO micro-pyramids. Self-assembled catalyst-free p-CuO micro-pyramid arrays are fabricated on a pre-ablated Si substrate by pulsed laser deposition without a need for a catalyst layer or seeding, while the solution-processed n-ZnO QDs are synthesized by the femtosecond-laser ablation in liquid technique. The photodetector is fabricated by spray-coating ZnO QDs on a CuO micro-pyramid array. The photodetector performance is optimized via a p-n junction structure as both p-ZnO QDs and p-CuO micro-pyramid layers are characterized by wide band gap energies. Two photodetectors (with and without CuO micro-pyramids) are fabricated to show the role of p-CuO in enhancing the device performance. The n-ZnO QD/p-CuO micro-pyramid/Si photodetector is characterized by a superior photo-responsivity of ∼956 mA/W at 244 nm with a faster photoresponse (

Introduction:according to the latest World Drug Report, 271 million people worldwide (5.5% of the global population) aged 15-64 years are drug users. Drug addiction and trafficking became an urgent public health problem that affects human health and social life. Aim: a cross-sectional study was conducted from January 2016 to December 2018, to identify the socio-demographic profile of drug users captured by the anti-narcotics squad in north of Tunisia (North African country) and to type, through toxicological analysis, the nature of the substances consumed. Methods:data were collected from expertise files of 11170 suspected drug users. Fresh urine samples were collected from suspected drugs users and submitted in the toxicology laboratory of the center for Urgent Medical Assistance (Tunis) for forensic urinalysis. Drugs screening was carried out by immunochemical methods. Positive samples were analyzed with gas chromatography coupled to mass selective detector (GC-MS) for confirmation. Results:the investigation revealed that drug users were mainly males 97.4% (sex ratio 37), the median age was 29 ± 7.91 years, 91.3% were singles and 79% were daily workers. On a total of 11170 urine samples screened, 5 409 (48.4%) were positives for illicit drugs. The prevalence of positive samples was 55.4% in 2016; 50.45% in 2017 and 40.8% in 2018. Cannabis was the most widely consumed drug (95%), followed by Benzodiazepines (1.2%), Buprenorphine (1%), cocaine (0.95%), MDMA (0.24%) and opiates (0.13%). Polydrug abuse was observed in 79 specimens (1.5%). Conclusion:this study provides an overview of the illicit drug consumption in the north of Tunisia (knowing that nowadays epidemiological data are almost same since 2016) in order to set up an effective policy to fight against drugs and addictive behaviors and to provide health professionals with the epidemiological elements necessary for better medical care of drug users.

The present article aimed at studying the relationship between project-based organization and competence management practices (recruitment, assessment, training, compensation and career management). The central question of our research is formulated as follows: To what extent does project-based organization influence competence management practices? To answer this question, we adopted a quantitative study. A total of 156 Tunisian project managers participated in our survey. We tested our hypotheses through a linear regression analysis. The results show that the majority of competence management practices, namely recruitment, evaluation and training, are more relevant to project-based organizations and thus the three first hypotheses are confirmed. However, other practices, like remuneration and career management, are insensitive to project activities.

High-resolution scanning transmission electron microscopy (HR-STEM) with spherical aberration correction enables researchers to peer into two-dimensional (2D) materials and correlate the material properties with those of single atoms. The maximum intensity of corrected electron beam is confined in the area having sub-angstrom size. Meanwhile, the residual threefold astigmatism of the electron probe implies a triangular shape distribution of the intensity, whereas its tails overlap and thus interact with several atomic species simultaneously. The result is the resonant modulation of contrast that interferes the determination of phase transition of 2D materials. Here, we theoretically reveal and experimentally determine the origin of resonant modulation of contrast and its unintended impact on violating the power-law dependence of contrast on coordination modes between transition metal and chalcogenide atoms. The finding illuminates the correlation between atomic contrast, spatially inequivalent chalcogenide orientation, and residual threefold astigmatism on determining the atomic structure of emerging 2D materials.

The presence of localized trap states on the surface of CsPbCl3 perovskite nanocrystals (NCs) is one of the greatest challenges precluding the development of optoelectronic applications of these NCs. Passivation of these defect sites provides a promising pathway to remediating their electronic and optical properties, such as the photoluminescence quantum yield (PLQY). Herein, we demonstrate a postsynthetic dual-surface treatment using trivalent metal ion salts, i.e., YCl3, as a new passivation approach that enhances the PLQY up to 60% while preserving the NC size and crystal structure. Such remarkable enhancement of the PLQY along with prolongation of the average PL lifetimes of treated NCs samples indicates effective passivation of the surface defects and subsequent suppression of the formation of surface nonradiative recombination centers. As a segue toward optoelectronic applications, we probed the photoelectric performance of the NCs using ultraflexible devices; we found that YCl3-treated CsPbCl3 NC f...

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.

Insertion of alkali metal ions, especially Na, is a well-established method to significantly increase the power conversion efficiency of copper indium gallium selenide (CIGSe)-based photovoltaic devices. However, although it is known that Na ions mostly reside on the surface of CIGSe layer following diffusion, the exact mechanism of how Na affects the carrier dynamics of CIGSe still remains ambiguous. This is mainly due to the unavailability of suitable surface-sensitive techniques. Herein, we employ four-dimensional scanning ultrafast electron microscopy (4D S-UEM), which has the unique capability of mapping the charge carrier dynamics in real time and space selectively on the materials surfaces, to directly observe the effect of Na insertion on the carrier dynamics of shelled CIGSe film. It is found that an additional layer of NaF to the thin film of ZnS-shelled CIGSe nanocrystals not only increases the grain size and improves the texture of the film but, more importantly, reduces fast electron trap cha...

Lead intoxication risks were studied in a community of ceramic folk art workers in Nabeul (Tunisia),where the manufacture of low temperature lead ceramic ware is a family tradition and often the only source of income. Data onlifestyle, working conditions and clinical disorders were collected from workers.31 potters working in five different workshopswere included in this study. Blood lead levels wereanalyzed by graphite furnaceatomic absorption spectrometry.Blood lead levels ranged from 40 to 540 μg/L, with a mean of 220.3 μg/L. 42 percent of potters had a blood lead level over 200 μg/L and 13 % over 400 μg/L,which is over the World Health Organization guidelinesfor removingworkersfrom exposure,as this is the concentration over which renal damage is accelerated.In the community of ceramic folk art workers living in north-eastern Tunisia, blood lead concentrations were significantly higher (p

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 (

Although halide perovskite nanocrystals (NCs) are promising materials for optoelectronic devices, they suffer severely from chemical and phase instabilities. Moreover, the common capping ligands like oleic acid and oleylamine that encapsulate the NCs will form an insulating layer, precluding their utility in optoelectronic devices. To overcome these limitations, we develop a postsynthesis passivation process for CsPbI3 NCs by using a bidentate ligand, namely 2,2′-iminodibenzoic acid. Our passivated NCs exhibit narrow red photoluminescence with exceptional quantum yield (close to unity) and substantially improved stability. The passivated NCs enabled us to realize red light-emitting diodes (LEDs) with 5.02% external quantum efficiency and 748 cd/m2 luminance, surpassing by far LEDs made from the nonpassivated NCs.

Aim of the work: Our objective was to analyze the content and quality of referral letters to rheumatology consultation. Patients and methods: This is a cross-sectional study conducted on the rheumatology consultations in a tertiary hospital over six months (April-October 2014). Patients were interviewed and their rheumatology consultation referral letters analyzed. The relevance of referent reasons, suggested diagnosis and additional tests requested prior to recruitment were studied. Results: We studied 302 referral letters for rheumatology consultation. The average age of patients was 55.34 ± 15 years (13–85). The sex ratio M/F was 0.3. All patients consulted for painful symptoms affecting mainly the lumbar spine (20%) and knees (20%). The current clinical problem was appropriately presented in 43% of the referral letters. Only 6 letters (2%) were illegible, 28 letters did not contain the consultation date (9%). General practitioners represented 59% of referring physicians. The age and patient history were more detailed in the letters written by physician specialists (p = 0.002 and p

Ultrathin layers of native oxides on the surface of photovoltaic materials may act as very efficient carrier trapping/recombination centers, thus significantly affecting their interfacial photophysical properties. How ultrathin oxide layers affect the surface and interface carrier dynamics cannot be selectively accessed by conventional ultrafast transient spectroscopic methods due to the deep penetration depth (tens to thousands of nanometers) of the pump/probe laser pulses. Herein, scanning ultrafast electron microscopy (S-UEM) at a low voltage of 1 keV electrons was recently developed at KAUST to selectively map the ultrafast charge carrier dynamics of a few layers on the top surfaces of photovoltaic materials. Unlike high-voltage 30 keV experiments, at 1 keV, the depth of detected secondary electrons (SEs) underneath the surface is significantly reduced 5 times, thus making it possible to visualize the dynamics of charge carrier from the uppermost surface of photoactive layers. More specifically, this new approach has been employed to explore and decipher the tremendous impact of native oxide layers and oxygen defect states on charge carrier dynamics in space and time simultaneously at sub-nanometer levels on several photovoltaic material surfaces, including Si, GaAs, CdTe, and CdZnTe single crystals. Interestingly, the contrast in the SEs time-resolved difference images switched from a dark "energy-loss mechanism" to a bright "energy-gain mechanism" only by removing the layers of surface oxides. Moreover, the charge carrier recombination was estimated and found to be dramatically affected by the native oxide layers. The density functional theory (DFT) calculations demonstrate that the work function of oxygen-terminated Si surface also increases slightly upon optical excitation and makes for less SE intensity, providing another piece of evidence that the origin of the dark contrast observed on these material surfaces should be assigned to the surface oxide formation, mainly oxygen defect states in the band gap and/or work function increment. Our findings provide a new method and pave the way for evaluating the effect of surface morphology and defects, including but not limited to native oxide, on charge carrier dynamics, and interfacial properties of photovoltaic absorber layers.

Environmental contamination by heavy metals has been a matter of great concern in many countries for several decades. Human exposure to such elements may cause adverse health effects and young children are particularly at risk. Many matrixes have been used for determination of metal exposure levels. Hard tissues such as teeth and bones have some advantages compared to other matrix. Dental tissues are considered to be suitable for long-term metal exposure due to their stability, resistance to physical and chemical degradation and their good preservation over time. Several studies have analyzed the teeth of animals for assessment the relationship between increased fluoride exposure and dental fluorosis, however few studies have been conducted on human teeth. Thus, the aim of the present study was to assess the reliability of human teeth matrix used as a biomarker for fluoride environmental pollution in Tunisia, and to evaluate the relationship with place of residence, age, dental caries and sex. Teeth samples (n=123) were collected from individuals living in Gafsa (fluoride-polluted area which inhabitants are to a great extent exposed to heavy metals) and Tunis (non polluted area). Samples were analyzed using a potentiometric method. The fluoride concentration was found to be significantly higher in teeth from Gafsa samples than those from Tunis. Their control levels were respectively 6793.1μg/g and 1068.8μg/g. The results indicate that there is a clear relation between fluoride concentration and residence of living. An increased level of dental fluorosis in fluoridated communities has been used to evaluate historical chronic exposure to fluoride in these communities, despite constant fluoride levels in the drinking-water. The fluoride concentration was also observed to be significantly increased in polluted area with age and in carious teeth whereas, no significant difference was observed for sex. Our study confirms well that human teeth used as a bioindicator for environmental pollution provide good chronological information on exposure, and highlighted the risks incurred by consumers living in such polluted area.

Parasitic absorption in transparent electrodes is one of the main roadblocks to enabling power conversion efficiencies (PCEs) for perovskite‐based tandem solar cells beyond 30%. To reduce such losses and maximize light coupling, the broadband transparency of such electrodes should be improved, especially at the front of the device. Here, the excellent properties of Zr‐doped indium oxide (IZRO) transparent electrodes for such applications, with improved near‐infrared (NIR) response, compared to conventional tin‐doped indium oxide (ITO) electrodes, are shown. Optimized IZRO films feature a very high electron mobility (up to ≈77 cm2 V−1 s−1), enabling highly infrared transparent films with a very low sheet resistance (≈18 Ω □−1 for annealed 100 nm films). For devices, this translates in a parasitic absorption of only ≈5% for IZRO within the solar spectrum (250–2500 nm range), to be compared with ≈10% for commercial ITO. Fundamentally, it is found that the high conductivity of annealed IZRO films is directly linked to promoted crystallinity of the indium oxide (In2O3) films due to Zr‐doping. Overall, on a four‐terminal perovskite/silicon tandem device level, an absolute 3.5 mA cm−2 short‐circuit current improvement in silicon bottom cells is obtained by replacing commercial ITO electrodes with IZRO, resulting in improving the PCE from 23.3% to 26.2%.

We study the band discontinuity at the GaN/single-layer (SL) WSe2 heterointerface. The GaN thin layer is epitaxially grown by molecular beam epitaxy on chemically vapor deposited SL-WSe2/c-sapphire. We confirm that the WSe2 was formed as an SL from structural and optical analyses using atomic force microscopy, scanning transmission electron microscopy, micro-Raman, absorbance, and microphotoluminescence spectra. The determination of band offset parameters at the GaN/SL-WSe2 heterojunction is obtained by high-resolution X-ray photoelectron spectroscopy, electron affinities, and the electronic bandgap values of SL-WSe2 and GaN. The valence band and conduction band offset values are determined to be 2.25 ± 0.15 and 0.80 ± 0.15 eV, respectively, with type II band alignment. The band alignment parameters determined here provide a route toward the integration of group III nitride semiconducting materials with transition metal dichalcogenides (TMDs) for designing and modeling of their heterojunction-based electr...

Hybrid organic/inorganic perovskites have recently emerged as an important class of materials and have exhibited remarkable performance in photovoltaics. To further improve their device efficiency, an insightful understanding of the interfacial charge transfer (CT) process is required. Here, we report the first direct experimental observation of the tremendous effect that the shape of perovskite nanocrystals (NCs) has on interfacial CT in the presence of a molecular acceptor. A dramatic change in CT dynamics at the interfaces of three different NC shapes, spheres, platelets, and cubes, is recorded. Our results clearly demonstrate that the mechanism of CT is significantly affected by the NC shape. More importantly, the results demonstrate that complexation on the NC surface acts as an additional driving force not only to tune the CT dynamics but also to control the reaction mechanism at the interface. This observation opens a new venue for further developing perovskite NCs-based applications.

A two-step ligand-exchange strategy is developed, in which the long-carbon- chain ligands on all-inorganic perovskite (CsPbX3 , X = Br, Cl) quantum dots (QDs) are replaced with halide-ion-pair ligands. Green and blue light-emitting diodes made from the halide-ion-pair-capped quantum dots exhibit high external quantum efficiencies compared with the untreated QDs.

The aim of the study was the biomonitoring of the chronic exposure to Pb by measuring its levels in blood, urine, and hair of battery workers. Blood lead (BPb), urinary lead (UPb), hair lead (HPb), and urinary δ-aminolevulinic acid (UALA) levels were determined for 52 workers in a battery plant and compared to those of 20 non-occupational exposed subjects (controls). BPb and UPb levels were determined by graphite furnace atomic absorption spectrometry (GFAAS). HPb levels were measured by triple quadrupole ICP-MS and UALA levels were determined using cation exchanger column. The measured levels were significantly higher compared to the controls exceeding the OSHA cutoff values (p

The fields of photovoltaics, photodetection and light emission have seen tremendous activity in recent years with the advent of hybrid organic-inorganic perovskites. Yet, there have been far fewer reports of perovskite-based field-effect transistors. The lateral and interfacial transport requirements of transistors make them particularly vulnerable to surface contamination and defects rife in polycrystalline films and bulk single crystals. Here, we demonstrate a spatially-confined inverse temperature crystallization strategy which synthesizes micrometre-thin single crystals of methylammonium lead halide perovskites MAPbX3 (X = Cl, Br, I) with sub-nanometer surface roughness and very low surface contamination. These benefit the integration of MAPbX3 crystals into ambipolar transistors and yield record, room-temperature field-effect mobility up to 4.7 and 1.5 cm2 V−1 s−1 in p and n channel devices respectively, with 104 to 105 on-off ratio and low turn-on voltages. This work paves the way for integrating hybrid perovskite crystals into printed, flexible and transparent electronics., The methylammonium lead halide perovskites have shown excellent optoelectronic properties but the field-effect transistors are much less studied. Here Yu et al. synthesize micrometer-thin crystals of perovskites with low surface contamination and make ambipolar transistor devices with high mobilities.

Resume Objectifs L’actinomycose est une maladie suppurative granulomateuse rare, peu connue, plus frequente chez la femme, favorisee par l’usage a visee contraceptive du dispositif intra-uterin (DIU). La localisation pelvienne est la plus rare avec une extension aux organes de voisinage rendant le diagnostic preoperatoire difficile et le tableau clinique trompeur. Le diagnostic precoce de cette affection conditionne la strategie therapeutique et permet d’eviter des interventions mutilantes surtout chez les femmes jeunes. Methodes Nous avons analyse les dossiers des patientes qui ont consulte au service de gynecologie obstetrique de l’hopital de Ben Arous (Tunisie) entre janvier 2003 et decembre 2013 pour un syndrome douloureux pelvien et dont le diagnostic d’actinomycose a ete suspecte par les donnees cliniques et de l’imagerie et confirme grâce a l’examen anatomopathologique. Resultats Huit cas d’actinomycose abdominopelvienne d’origine gynecologique ont ete diagnostiques durant la periode d’etude. Sept patientes etaient porteuses d’un dispositif intra-uterin, avec une duree de port moyenne de 5 ans. Les signes fonctionnels etaient essentiellement les douleurs pelviennes et la fievre. L’examen physique des patientes avait montre essentiellement deux tableaux cliniques : un syndrome tumoral pelvien ou abdominopelvien et un tableau d’abces pelvien ou de pelviperitonite. Les examens radiologiques n’ont permis d’evoquer le diagnostic d’actinomycose, seulement chez une seule patiente, chez qui une biopsie percutanee a confirme le diagnostic histologiquement sans avoir recours a un geste operatoire. Les gestes operatoires effectues etaient varies selon les cas. Le diagnostic d’actinomycose a ete pose par etude histologique sans avoir aucun cas d’isolement bacteriologique. Toutes les patientes ont recu un traitement antibiotique et la penicilline representait l’antibiotherapie de choix. L’evolution ulterieure a ete favorable. Conclusion Le diagnostic d’actinomycose doit etre evoque devant toute masse abdominale invasive d’apparence neoplasique et en cas de tableau clinique d’infection genitale surtout chez les patientes porteuses d’un DIU depuis 5 ans ou plus.

Introducing dopants into InGaN NWs is known to significantly improve their device performances through a variety of mechanisms. However, to further optimize device operation under the influence of large specific surfaces, thorough knowledge of ultrafast dynamical processes at the surface and interface of these NWs is imperative. Here, we describe the development of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) as an extremely surface-sensitive method to directly visualize in space and time the enormous impact of silicon doping on the surface-carrier dynamics of InGaN NWs. Two time regimes of surface dynamics are identified for the first time in a 4D S-UEM experiment: an early time behavior (within 200 ps) associated with the deferred evolution of secondary electrons due to the presence of localized trap states that decrease the electron escape rate and a longer time scale behavior (several ns) marked by accelerated charge carrier recombination. The results are further corroborated by conductivity studies carried out in the dark and under illumination.

In Tunisia, there are about 478 species of plants commonly used in folk medicine. Medicinal plants and herbal remedies used are responsible for 2% of intoxications listed by Tunisian National Poison Center. Most cases are related to confusion between edible plants and toxic plants lookalikes or to an excessive consumption of therapeutic plants. We report the case of a 58-year-old man admitted to the Emergency Department of the Regional Hospital of Zaghouan (Tunisia), with renal failure and rhabdomyolysis. The patient reported having daily consumption of a homemade tea based onMediterranean Buckthornroots, during the last 6 months to treat type 2 diabetes. The aim of this work was to establish an association between the consumption of the herbal remedy and the occurrence of both renal failure and rhabdomyolysis. No similar cases have been reported in recent literature.

Otosclerosis is an osteodystrophia of the otic capsule, responsible for hearing loss by blocking of the stapes footplate. The purpose of this study was to evaluate the reliability of computed tomography (CT) in the positive diagnosis of otosclerosis, to compare the radiological findings to those intraoperatively, and to seek a correlation between imaging data and postoperative audiometric results. This is a retrospective study of 60 patients having otosclerosis, treated in our department between 2009 and 2011. All patients underwent an otoscopic examination, pure tone and vocal audiometry, impedancemetry and petrous CT scan. At petrous CT scan, a footplate thickening was found in 9 cases. Labyrinthine bone hypodensity was noted in 51 cases. Sensitivity of CT in the diagnosis of otosclerosis was 100%. Regarding the operative findings and their correlation with imaging, we found that among the 7 facial canal procidences reported intraoperatively, CT had identified 6, with a sensitivity of 86%. Of the 53 facial nerve in normal position intraoperatively, CT had only identified 34, with a specificity of 64%. Regarding the ossicles, there were 6 cases of abnormalities of the incus, among them 3 were identified on CT, with a sensitivity of 50%. The 54 patients with normal ossicular chain intraoperatively were all identified as such on CT, with a specificity of 100% (p = 0.001). For correlation between imaging and postoperative results, it was found that patients with extended otosclerosis had lower postoperative audiometric improvement than those having localized disease (p < 0.05). Computed tomography is necessary for the diagnosis of otosclerosis. It also helps, with good sensitivity and specificity, seeking for anatomical variants that the surgeon could possibly encounter during surgical procedure. Finally, there is a statistically significant correlation between imaging data and postoperative audiometric results, allowing establishing a functional prognosis even before surgery.

A dramatic improvement in electrical conductivity is necessary to make conductive polymer fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators. In this study, high-performance poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) conjugated polymer microfibers were fabricated via wet-spinning followed by hot-drawing. Due to the combined effects of the vertical hot-drawing process and doping/de-doping the microfibers with ethylene glycol (EG), we achieved a record electrical conductivity of 2804 S cm−1. This is, to the best of our knowledge, a six-fold improvement over the best previously reported value for PEDOT/PSS fibers (467 S cm−1) and a two-fold improvement over the best values for conductive polymer films treated by EG de-doping (1418 S cm−1). Moreover, we found that these highly conductive fibers experience a semiconductor–metal transition at 313 K. They also have superior mechanical properties with a Young's modulus up to 8.3 GPa, a tensile strength reaching 409.8 MPa and a large elongation before failure (21%). The most conductive fiber also demonstrates an extraordinary electrical performance during stretching/unstretching: the conductivity increased by 25% before the fiber rupture point with a maximum strain up to 21%. Simple fabrication of the semi-metallic, strong and stretchable wet-spun PEDOT/PSS microfibers described here could make them available for conductive smart electronics.

Ectopic molar pregnancy is a rare occurrence and consequently not often considered as a diagnostic possibility. We report two cases of molar hydatidiform tubal pregnancy. Diagnosis of ectopic pregnancy was confirmed on clinical biological and sonographic investigations. Diagnosis of molar pregnancy was done on histopathology. The clinical course was favorable for both patients. Although rare, molar changes can occur at any site of an ectopic pregnancy. Clinical diagnosis of a molar pregnancy is difficult but histopathology is the gold standard for diagnosis.