Engineered eco-friendly composite membranes with superhydrophobic/hydrophilic dual-layer for DCMD system.

Considerable advancements have been made in the development of hydrophobic membranes for membrane distillation (MD). Nonetheless, the environmentally responsible disposal of these membranes poses a critical concern due to their synthetic composition. Herein, an eco-friendly dual-layered biopolymer-based membrane was fabricated for water desalination. The membrane was electrospun from two bio-polymeric layers. The top hydrophobic layer comprises polycaprolactone (PCL) and the bottom hydrophilic layer from cellulose acetate (CA). Additionally, silica nanoparticles (SiO2 NPs) were electrosprayed onto the top layer of the dual-layered PCL/CA membrane to enhance the hydrophobicity. The desalination performance of the modified PCL-SiO2/CA membrane was compared with the unmodified PCL/CA membrane using a direct contact membrane distillation (DCMD) unit. Results revealed that silica remarkably improves membrane hydrophobicity. The modified PCL-SiO2/CA membrane demonstrated a significant increase in water contact angle of 152.4° compared to 119° for the unmodified membrane. In addition, PCL-SiO2/CA membrane has a smaller average pore size of 0.23 ± 0.16 µm and an exceptional liquid entry pressure of water (LEPw), which is 3.8 times higher than that of PCL/CA membrane. Moreover, PCL-SiO2/CA membrane achieved a durable permeate flux of 15.6 kg/m2.h, while PCL/CA membrane showed unstable permeate flux decreasing approximately from 25 to 12 kg/m2.h over the DCMD test time. Furthermore, the modified PCL-SiO2/CA membrane achieved a high salt rejection value of 99.97% compared to a low value of 86.2% for the PCL/CA membrane after 24 h continuous DCMD operation. In conclusion, the proposed modified PCL-SiO2/CA dual-layer biopolymeric-based membrane has considerable potential to be used as an environmentally friendly membrane for the MD process.

Engineering of Multifunctional Nanocomposite Membranes for Wastewater Treatment: Oil/Water Separation and Dye Degradation.

Multifunctional membrane technology has gained tremendous attention in wastewater treatment, including oil/water separation and photocatalytic activity. In the present study, a multifunctional composite nanofiber membrane is capable of removing dyes and separating oil from wastewater, as well as having antibacterial activity. The composite nanofiber membrane is composed of cellulose acetate (CA) filled with zinc oxide nanoparticles (ZnO NPs) in a polymer matrix and dipped into a solution of titanium dioxide nanoparticles (TiO2 NPs). Membrane characterization was performed using transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and Fourier transform infrared (FTIR), and water contact angle (WCA) studies were utilized to evaluate the introduced membranes. Results showed that membranes have adequate wettability for the separation process and antibacterial activity, which is beneficial for water disinfection from living organisms. A remarkable result of the membranes' analysis was that methylene blue (MB) dye removal occurred through the photocatalysis process with an efficiency of ~20%. Additionally, it exhibits a high separation efficiency of 45% for removing oil from a mixture of oil-water and water flux of 20.7 L.m-2 h-1 after 1 h. The developed membranes have multifunctional properties and are expected to provide numerous merits for treating complex wastewater.

Evaluation of a Modified Version of the United Kingdom Working Party Diagnostic Criteria for Atopic Dermatitis in Tunisia.

BACKGROUND: For many years, the United Kingdom (UK) Working Party diagnostic criteria for atopic dermatitis (AD) have represented the criteria of choice for epidemiological studies. A recent study has reported a low sensitivity of these criteria among Tunisian patients, probably because of some epidemiologic characteristics of AD in our country. OBJECTIVE: Our objective was to validate a modified version of the UK Working Party criteria for AD in Tunisia by establishing their sensitivity, specificity, and positive predictive value and negative predictive value. MATERIALS AND METHODS: This case-control study was performed over a period of 18 months in our dermatology department in Tunisia. The diagnosis of AD was established clinically by 2 dermatologists who specialized in dermatoallergology. Based on the UK Working Party diagnostic criteria and respecting the epidemiological peculiarities of AD in Tunisia, we proposed a modified version of diagnostic criteria adapted to Tunisian AD. The modifications concerned the first, fourth, and fifth minor criteria of the UK Working Party diagnostic criteria list. RESULTS: We collected 156 patients and 156 controls. The mean age of AD onset was 7 years and 9 months. The inverted topography of lesions was found in 67.9% of cases. The sensitivity, specificity, positive predictive, value and negative predictive value were, respectively, 56.4%, 97.4%, 95.65%, and 69.09% for the UK Working Party diagnostic criteria and 89.1%, 95.5%, 95.1%, and 89.7% for the modified version. CONCLUSIONS: This modified version of the UK criteria seems to be a practical diagnosis tool for AD in Tunisia.

Membranes for Oil/Water Separation: A Review.

Recent advancements in separation and membrane technologies have shown a great potential in removing oil from wastewaters effectively. In addition, the capabilities have improved to fabricate membranes with tunable properties in terms of their wettability, permeability, antifouling, and mechanical properties that govern the treatment of oily wastewaters. Herein, authors have critically reviewed the literature on membrane technology for oil/water separation with a specific focus on: 1) membrane properties and characterization, 2) development of various materials (e.g., organic, inorganic, and hybrid membranes, and innovative materials), 3) membranes design (e.g., mixed matrix nanocomposite and multilayers), and 4) membrane fabrication techniques and surface modification techniques. The current challenges and future research directions in materials and fabrication techniques for membrane technology applications in oil/water separation are also highlighted. Thus, this review provides helpful guidance toward finding more effective, practical, and scalable solutions to tackle environmental pollution by oils.

Synthesis of Carbon-Supported PdIrNi Catalysts and Their Performance towards Ethanol Electrooxidation.

Direct ethanol fuel cells (DEFCs) have shown a high potential to supply energy and contribute to saving the climate due to their bioethanol sustainability and carbon neutrality. Nonetheless, there is a consistent need to develop new catalyst electrodes that are active for the ethanol oxidation reaction (EOR). In this work, two C-supported PdIrNi catalysts, that have been reported only once, are prepared via a facile NaBH4 co-reduction route. Their physiochemical characterization (X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS)) results show alloyed PdIrNi nanoparticles that are well dispersed (<3 nm) and exist in metallic state that is air-stable apart from Ni and, slightly, Pd. Their electrocatalytic activity towards EOR was evaluated by means of cyclic voltammetry (CV) and chronoamperometry (CA). Even though the physiochemical characterization of PdIrNi/C and Pd4Ir2Ni1/C is promising, their EOR performance has proven them less active than their Pd/C counterpart. Although the oxidation current peak of Pd/C is 1.8 A/mgPd, it is only 0.48 A/mgPd for Pd4Ir2Ni1/C and 0.52 A/mgPd for PdIrNi/C. These results were obtained three times and are reproducible, but since they do not add up with the sound PdIrNi microstructure, more advanced and in situ EOR studies are necessary to better understand the poor EOR performance.

Development and Characterization of Cellulose/Iron Acetate Nanofibers for Bone Tissue Engineering Applications.

In tissue engineering, design of biomaterial with a micro/nano structure is an essential step to mimic extracellular matrix (ECM) and to enhance biomineralization as well as cell biocompatibility. Composite polymeric nanofiber with iron particles/ions has an important role in biomineralization and collagen synthesis for bone tissue engineering. Herein, we report development of polymeric cellulose acetate (CA) nanofibers (17 wt.%) and traces of iron acetates salt (0.5 wt.%) within a polymeric solution to form electrospinning nanofibers mats with iron nanoparticles for bone tissue engineering applications. The resulting mats were characterized using field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The resulted morphology indicated that the average diameter of CA decreased after addition of iron from (395 ± 30) to (266 ± 19) nm and had dense fiber distributions that match those of native ECM. Moreover, addition of iron acetate to CA solution resulted in mats that are thermally stable. The initial decomposition temperature was 300 °C of CA/Fe mat > 270 °C of pure CA. Furthermore, a superior apatite formation resulted in a biomineralization test after 3 days of immersion in stimulated environmental condition. In vitro cell culture experiments demonstrated that the CA/Fe mat was biocompatible to human fetal-osteoblast cells (hFOB) with the ability to support the cell attachment and proliferation. These findings suggest that doping traces of iron acetate has a promising role in composite mats designed for bone tissue engineering as simple and economically nanoscale materials. Furthermore, these biomaterials can be used in a potential future application such as drug delivery, cancer treatment, and antibacterial materials.

Engineering and Characterization of Antibacterial Coaxial Nanofiber Membranes for Oil/Water Separation.

In the present study, a coaxial nanofiber membrane was developed using the electrospinning technique. The developed membranes were fabricated from hydrophilic cellulose acetate (CA) polymer and hydrophobic polysulfone (PSf) polymer as a core and shell in an alternative way with addition of 0.1 wt.% of ZnO nanoparticles (NPs). The membranes were treated with a 2M NaOH solution to enhance hydrophilicity and thus increase water separation flux. Chemical and physical characterizations were performed, such as Fourier transform infrared (FTIR) spectroscopy, and surface wettability was measured by means of water contact angle (WCA), mechanical properties, surface morphology via field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and microscopy energy dispersive (EDS) mapping and point analysis. The results show higher mechanical properties for the coaxial nanofiber membranes which reached a tensile strength of 7.58 MPa, a Young's modulus of 0.2 MPa, and 23.4 M J.m-3 of toughness. However, treated mebranes show lower mechanical properties (tensile strength of 0.25 MPa, Young's modulus of 0.01 MPa, and 0.4 M J.m-3 of toughness). In addition, the core and shell nanofiber membranes showed a uniform distribution of coaxial nanofibers. Membranes with ZnO NPs showed a porous structure and elimination of nanofibers after treatment due to the formation of nanosheets. Interestingly, membranes changed from hydrophobic to hydrophilic (the WCA changed from 90 ± 8° to 14 ± 2°). Besides that, composite nanofiber membranes with ZnO NPs showed antibacterial activity against Escherichia coli. Furthermore, the water flux for the modified membranes was improved by 1.6 times compared to the untreated membranes.

Strategic design of a Mussel-inspired in situ reduced Ag/Au-Nanoparticle Coated Magnesium Alloy for enhanced viability, antibacterial property and decelerated corrosion rates for degradable implant Applications.

Magnesium (Mg) and its alloys have attracted much attention as a promising candidate for degradable implant applications however the rapid corrosion of magnesium inside the human body greatly limits its use as an implant material. Therefore, coating the alloy surface with a multifunctional film is a promising way to overcome the drawbacks. Here we propose for the first time a multifunction layer coating to enhance the cell viability, antibacterial property and decelerated corrosion rates to act as a novel material to be used for degradable implant Applications. For that, the magnesium alloy (AZ31) was first treated with hydrofluoric acid (HF) and then dopamine tris Hydrochloric acid (tris-HCL) solution. The reducing catechol groups in the polydopamine (PD) layer subsequently immobilize silver/gold ions in situ to form uniformly dispersed Ag/Au nanoparticles on the coating layer. The successful formation of Ag/Au nanoparticles on the HF-PD AZ31 alloy was confirmed using XPS and XRD, and the morphology of all the coated samples were investigated using SEM images. The alloy with HF-PDA exhibit enhanced cell attachment and proliferation. Moreover, the nanoparticle immobilized HF-PD alloy exhibited dramatic corrosion resistance enhancement with superior antibacterial properties and accountable biocompatibility. Thus the result suggest that HF-PD Ag/Au alloy has great potential in the application of degradable implant and the surface modification method is of great significance to determine its properties.

Facile synthesis of TiO2/ZrO2 nanofibers/nitrogen co-doped activated carbon to enhance the desalination and bacterial inactivation via capacitive deionization.

Capacitive deionization, as a second generation electrosorption technique to obtain water, is one of the most promising water desalination technologies. Yet; in order to achieve high CDI performance, a well-designed structure of the electrode materials is needed, and is in high demand. Here, a novel composite nitrogen-TiO2/ZrO2 nanofibers incorporated activated carbon (NACTZ) is synthesized for the first time with enhanced desalination efficiency as well as disinfection performance towards brackish water. Nitrogen and TiO2/ZrO2 nanofibers are used as the support of activated carbon to improve its low capacitance and hydrophobicity, which had dramatically limited its adequacy during the CDI process. Importantly, the as-fabricated NACTZ nanocomposite demonstrates enhanced electrochemical performance with significant specific capacitance of 691.78 F g-1, low internal resistance and good cycling stability. In addition, it offers a high capacitive deionization performance of NACTZ yield with electrosorptive capacity of 3.98 mg g-1, and, good antibacterial effects as well. This work will provide an effective solution for developing highly performance and low-cost design for CDI electrode materials.

A Multifunctional Zinc Oxide/Poly(Lactic Acid) Nanocomposite Layer Coated on Magnesium Alloys for Controlled Degradation and Antibacterial Function.

In the present work, magnesium (Mg) AZ31 alloy was coated with a multifunctional membrane layer composed of ZnO nanoparticles (NPs) embedded in a poly(lactic acid) (PLA) matrix. We aimed to produce a stable coating that would be used to control the degradation rate of the Mg alloy and promote a local antibacterial activity. ZnO NPs were dispersed at 5 and 10 wt % in a PLA solution and dip-coated onto the AZ31 substrate. Surface topography, chemical composition, thickness, electrochemical corrosion performance, mass variation, antibacterial activity, adhesion performance, and cytotoxicity of an uncoated control and coated alloys were investigated. The results indicated that the incorporation of ZnO NPs at various concentrations affords a dramatic control over surface topography and degradation rates under in vitro and in vivo environmental conditions when compared to the uncoated Mg alloy control. In addition, the results confirmed that the coated layer exerts antibacterial properties and supports cell growth, indicating this system may have utility for bone tissue engineering applications.

Blastomyces dermatitidis in a Renal Transplant Recipient: A Case Report.

Fungal infections have an important role in organ transplant recipients, and in some cases can be lethal. Blastomycosis is rare in kidney transplantation. We present a case of cutaneous blastomycosis in a kidney transplant recipient in Tunisia, a country outside the known endemic countries. This case, with the very uncommon and unexpected diagnosis of blastomycosis, demonstrates the diversity of infections in transplant recipients and reflects the importance of histologic and serologic tests in the immunocompromised patient.

High-performance glucose biosensor based on chitosan-glucose oxidase immobilized polypyrrole/Nafion/functionalized multi-walled carbon nanotubes bio-nanohybrid film.

A highly electroactive bio-nanohybrid film of polypyrrole (PPy)-Nafion (Nf)-functionalized multi-walled carbon nanotubes (fMWCNTs) nanocomposite was prepared on the glassy carbon electrode (GCE) by a facile one-step electrochemical polymerization technique followed by chitosan-glucose oxidase (CH-GOx) immobilization on its surface to achieve a high-performance glucose biosensor. The as-fabricated nanohybrid composite provides high surface area for GOx immobilization and thus enhances the enzyme-loading efficiency. The structural characterization revealed that the PPy-Nf-fMWCNTs nanocomposite films were uniformly formed on GCE and after GOx immobilization, the surface porosities of the film were decreased due to enzyme encapsulation inside the bio-nanohybrid composite materials. The electrochemical behavior of the fabricated biosensor was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and amperometry measurements. The results indicated an excellent catalytic property of bio-nanohybrid film for glucose detection with improved sensitivity of 2860.3µAmM(-1)cm(-2), the linear range up to 4.7mM (R(2)=0.9992), and a low detection limit of 5µM under a signal/noise (S/N) ratio of 3. Furthermore, the resulting biosensor presented reliable selectivity, better long-term stability, good repeatability, reproducibility, and acceptable measurement of glucose concentration in real serum samples. Thus, this fabricated biosensor provides an efficient and highly sensitive platform for glucose sensing and can open up new avenues for clinical applications.

Development of polyamide-6,6/chitosan electrospun hybrid nanofibrous scaffolds for tissue engineering application.

The development of biofunctional and bioactive hybrid polymeric scaffolds seek to mitigate the current challenges in the emerging field of tissue engineering. In this paper, we report the fabrication of a biomimetic and biocompatible nanofibrous scaffolds of polyamide-6,6 (PA-6,6) blended with biopolymer chitosan via one step co-electrospinning technique. Different weight percentage of chitosan 10wt%, 15wt%, and 20wt% were blended with PA-6,6, respectively. The nanocomposite electrospun scaffolds mats enabled to provide the osteophilic environment for cells growth and biomineralization. The morphological and physiochemical properties of the resulted scaffolds were studied using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) spectroscopy. The improvement in hydrophilicity and mechanical strength of the bio-nanocomposite mesh with 20wt% chitosan embedded, was the desired avenue for adhesion, proliferation and maturation of osteoblast cells as compared to other sample groups and pure PA-6,6 fibrous mat. The biomineralization of the nanocomposite electrospun mats also showed higher ability to nucleate bioactive calcium phosphate (Ca/P) nanoparticles comparing to pristine PA-6,6. Furthermore, the biomimetic nature of scaffolds exhibited the cells viability and regeneration of pre-osteoblast (MC3T3-E1) cells which were assessed via in vitro cell culture test. Collectively, the results suggested that the optimized 20wt% of chitosan supplemented hybrid electrospun fibrous scaffold has significant effect in biomedical field to create osteogenic capabilities for tissue engineering.

[A multicenter study on profile of hypertension in focal segmental glomerulosclerosis in Tunisia]. / Profil de l'hypertension artérielle dans la hyalinose segmentaire et focale (HSF). Étude multicentrique de 116 cas en Tunisie.

UNLABELLED: Hypertension in focal segmental glomerulosclerosis is frequent and responsible for the progression of the disease. It could be a circumstance of the diagnosis of FSG or a complication of the nephrotic syndrome. PURPOSE: To determine the prevalence of hypertension among patients with FSG diagnosed in Tunisia and to describe the profile of patients with FSG having hypertension in contrast with who do not. PATIENTS AND METHODS: It was a retrospective multicentric study based on 116 patient files having FSG located in 5 specialized centers in Tunisia. RESULTS: The prevalence of hypertension among our patients was 41%, with a feminine predominance, their mean age was 36.34 ± 15.71 years. The systolic blood pressure among the patients with hypertension was 153.18 mmHg. The nephrotic syndrome was impure due to hypertension in 14.5% of the cases. The patients affected by hypertension were more obese. Proteinuria was higher among those not having hypertension than those with it, who score an average value of 5.67 ± 4.51 g/24h, with an insignificant difference. Serum creatinine at presentation was significantly higher among patients with hypertension. Vascular lesions were present at the renal biopsy among 39.45% of patients affected by hypertension, associated with renal failure in 58.50% of patients. The etiopathogenic treatment of FSG was essentially based on steroids full dose. CONCLUSION: Hypertension is often present in FSG and its' treatment must be as soon as possible in order to slow the progression of kidney chronic disease.

Emphysematous pyelonephritis in a diabetic patient on maintenance hemodialysis: a case report.

INTRODUCTION: Emphysematous pyelonephritis (EP) is an uncommon acute infection characterized by the presence of gas in the renal parenchyma. It is extremely rare in hemodialysis (HD) patients and diabetics account for most cases. It is a rapidly progressive and life threatening infection with a high mortality rate. We report a case of emphysematous pyelonephritis in a HD patient who was treated successfully with radical nephrectomy and antibiotic therapy. CASE REPORT: A 46-year-old diabetic male with end stage renal disease (ESRD) secondary to diabetic nephropathy and on maintenance HD for the last five years presented with a two weeks history of fever and loin pain. He was treated with oral ciprofloxacin for one week with no improvement. His blood culture isolated Escherichia coli. Computed tomography scan of the abdominal disclosed an enlarged left kidney with massive gaseous collections. Accordingly, the diagnosis of emphysematous pyelonephritis was put forward, the patient underwent left nephrectomy together with intravenous imipenum and amikacin with good clinical response. The removed kidney showed features of acute pyelonephritis with micro-abscesses on histopathology. . CONCLUSION: Emphysematous pyelonephritis should always be considered in diabetics presenting with fever, loin pain, and features of sepsis not responding to antibiotic therapy; even though being on dialysis. Computed tomography scan of the abdomen remains an early diagnostic tool. Early treatment with potent antibiotics with or without surgical intervention can save patients' life.

Predictors of early post-operative hypocalcemia after parathyroidectomy for secondary hyperparathyroidism.

We sought to identify predictors of development of early post-operative hypocalcemia after parathyroidectomy for secondary hyperparathyroidism. The patients were divided into two groups according to their serum calcium (Ca) levels within 24 hours of undergoing para-thyroidectomy: the hypocalcemia group (22 patients) with post-operative serum Ca levels of 2 mmol/L or less, and the normocalcemia group (48 patients), with post-operative serum Ca levels higher than 2 mmol/L. By using multivariate stepwise logistic regression analysis, high pre-operative serum Ca level had the strongest predictive value of development of early hypocalcemia with an adjusted odds ratio (aOR) of 3.01, followed by hypo-albuminemia (aOR = 2.72), younger age (aOR = 2.56), and high pre-operative alkaline phosphatase (ALP) levels (aOR = 2.28). We conclude that among patients with secondary hyperparathyroidism, age, levels of pre-operative serum Ca, ALP and albumin correlate positively with the development of early post-operative hypocalcemia. Patients with one of these factors should be monitored more closely in the early post-parathyroidectomy period.

[Nonketotic hyperglycemia-induced hemiballism]. / Hémiballisme secondaire à une hyperglycémie sans cétose.

Nonketotic hyperglycemia-induced hemichorea or hemiballism is a well-recognized entity that is rarely encountered. Particular computed tomography and magnetic resonance imaging findings have been described. The pathophysiological mechanism of this disease remains uncertain. We report here on two female patients that presented with hemiballism secondary to nonketotic hyperglycemia and underwent brain computed tomography and magnetic resonance imaging.