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87 result(s) for "Kacem, Imen"
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Microbial Biopolymers: From Production to Environmental Applications—A Review
Industrial evolution and agricultural expansion, explained by continuing population growth, have rendered enormous problems for the world throughout the past few decades, primarily because of waste generation. To reduce environmental impact and dependence on fossil fuels, scientists have explored replacing synthetic polymers with environmentally friendly and sustainable alternatives in many emergent applications. In this regard, microbial biopolymers have gained special attention. Many biopolymers originating from various strains of bacteria, fungi, and algae have been reported and their possible applications have increased rapidly. This review focuses on the wide range of microbial biopolymers, their characteristics, and factors influencing their production. The present study also describes the environmental applications of microbial biopolymers. The use of these biopolymers is very attractive as a value-added and sustainable approach to wastewater treatment. By acting as adsorbents, coagulants, and flocculants as well as filters in membrane processes, microbial biopolymers shine as promising solutions beyond conventional methods. They can be integrated into various stages of the treatment process, further enhancing the efficiency of wastewater treatment methods. Microbial biopolymer applications in bioremediation and soil stabilization are also reviewed. Several studies have demonstrated the strong potential of biopolymers in soil improvement due to their ability to minimize permeability, eliminate heavy metals, stabilize soil, and limit erosion. Challenges related to scaling up and the downstream processing of microbial biopolymers, as well as its future perspectives in environmental applications, are also discussed.
Eye movement study in essential tremor patients and its clinical correlates
Essential tremor (ET) encompasses a wide spectrum of motor and non-motor features. Eye movement abnormalities were first reported two decades ago as an atypical finding in ET. Today, a growing number of publications about eye movement abnormalities in neurodegenerative diseases have helped understand their pathophysiology and the basis of their phenotypic variability. Thus, addressing such aspect in ET may disentangle, based on the oculomotor network abnormalities, the dysfunctional brain pathways in ET. In this study, we aimed to describe neurophysiological eye movement abnormalities in ET and their clinical correlates in terms of cognition and other associated clinical signs. We conducted a cross-sectional study in a tertiary neurology referral center including consecutive ET patients and cognitively normal healthy controls (HC) matched for age and sex. The study protocol included the assessment of voluntary horizontal saccades, smooth pursuit, anti-saccades and saccadic intrusions. We assessed the associated motor signs, cognitive functions and the presence of rapid eye movement disorder (RBD). Sixty-two ET patients and 66 HC were enrolled in the study. Eye movement examination showed significant abnormalities in comparison with HC (46.7% vs 20%, p  = 0.002). Prolonged saccadic latency (38.7%, p  = 0.033) and altered smooth pursuit (38.7%, p  = 0.033) were the most common abnormalities in ET patients. Anti-saccadic errors (16% vs 0% in HC, p  = 0.034) correlated with the presence of rigidity ( p  = 0.046), bradykinesia ( p  = 0.001), cognitive dysfunction ( p  = 0.006), executive dysfunction ( p  = 0.0002), apraxia ( p  = 0.0001), altered verbal fluency ( p  = 0.013) and altered backward digit span ( p  = 0.045) along with the presence of RBD ( p  = 0.035). Square-wave jerks (11.5% vs 0% in HC, p  = 0.0024) correlated with rest tremor. A distinctive phenotype of ET could emerge out of this study characterized by anti-saccadic errors and a sub-cortical cognitive profile, consecutive to the disruption of the cerebello-thalamo-cortical loop. Patients with anti-saccadic errors could be cognitively vulnerable and in need of a close monitoring of their cognitive efficiency during the disease’s progression. They may as well convert to Parkinson disease if they present with parkinsonism, RBD and square-wave jerks and require, consequently, a close observation of their motor progression.
Determinants of cognitive impairment in multiple system atrophy: Clinical and genetic study
Classically, cognitive impairment (CI) was not considered as a paramount feature of multiple system atrophy(MSA) in both parkinsonian(MSA-P) and cerebellar(MSA-C) motor-subtypes. Yet, growing evidence indicates currently the commonness of such deficits among MSA patients in different populations. Our aim was to evaluate the cognitive profile of MSA Tunisian patients and to analyze the underlying clinical and genetic determinants. In a retrospective cross-sectional study, clinically-diagnosed MSA patients were included. All subjects underwent clinical and neuropsychological assessments to characterize their cognitive profile. The associations with their APOE genotype status were analyzed. Determinant of CI were specified. We included 71 MSA patients. Female gender(sex-ratio = 0.65) and MSA-P subtype(73%) were predominant. Mean age of disease onset was 59.1years. CI was found in 85.7% of patients(dementia in 12.7% and Mild cognitive impairment(MCI) in 73% of patients mainly of multiple-domain amnestic type(37.3%)). Mean MMSE score was lower among MSA-P compared to MSA-C(23.52 vs. 26.47;p = 0.027). Higher postural instability gait disorder(PIGD) and MDS-UPDRS-III scores were noted in demented MSA patients(p = 0.019;p = 0.015 respectively). The main altered cognitive domain was attention(64.8%). Executive functions and mood disorders were more affected in MSA-P(p = 0.029,p = 0.035 respectively). Clinical and neurophysiological study of dysautonomia revealed no differences across cognitive subtypes. APOE genotyping was performed in 51 MSA patients with available blood samples. Those carrying APOEε4 had 1.32 fold higher risk to develop CI, with lower MMSE score(p = 0.0001). Attention and language were significantly altered by adjusting the p value to APOEɛ4 carriers(p = 0.046 and p = 0.044 respectively). Executive dysfunction was more pronounced among MSA-PAPOEε4 carriers(p = 0.010). In this study, the main determinants of CI in Tunisian MSA patients were MSA-P motor-subtype, mainly of PIGD-phenotype, disease duration and APOEε4 carrying status, defining a more altered cognitive phenotype. This effect mainly concerned executive, attention and language functions, all found to be more impaired in APOEε4 carriers with variable degrees across MSA motor-subtypes.
Impact of APOE and MAPT genetic profile on the cognitive functions among Amyotrophic Lateral Sclerosis Tunisian patients
Amyotrophic Lateral Sclerosis(ALS) has traditionally been managed as a neuromuscular disorder. However, recent evidence suggests involvement of non-motor domains. This study aims to evaluate the impact of APOE and MAPT genotypes on the cognitive features of ALS. We included confirmed ALS cases from the Neurology department at Razi University Hospital, Tunisia. APOE and MAPT screening were conducted with Sanger sequencing validation, and preliminary screening for four main ALS genes was performed. Clinical phenotypes and genotypes were analyzed using appropriate tests, with healthy controls (HC) representing the Tunisian population. Two-hundred-seventy ALS patients were included, stratified as 213 spinal cases,49 with bulbar onset and 8 patients with generalized form with 140 HC. Regarding APOE , we reported high frequency of ALS cases carrier of APOE- ε4 isoform compared to controls( p  < 0.0001).We found a significant association between APOE -ɛ4 and ALS onset site ( p  = 0.05, r  = 0.33),with higher frequencies in bulbar onset patients. Cognitive signs were more frequent in ɛ4 carriers ( r  = 0.43, p  < 0.01),and a significant link was observed between dysexecutive functions and the APOE risk allele ( p  = 0.0495).Concerning the MAPT haplotypes, we reported high frequency of ALS cases carrier of MAPT H1-haplotype HC (94.45% and 72.14% respectively, p  < 0.001).Among ALS cases, MAPT -H1 showed a stronger positive correlation with the presence of oculomotor signs( p  = 0.05, r  = 0.28).As well as significant positive association between cognitive impairments( p  = 0.039, r  = 0.59). Our findings emphasize the correlation between APOE and MAPT genotypes and the cognitive features in our ALS patients. We also observed other interesting, though weak, significant correlations (with coefficients not exceeding 0.20),which require further validation in a larger cohort to confirm our results.
Characteristics, onset, and evolution of neurological symptoms in patients with COVID-19
BackgroundA wide range of neurological manifestations has been described in COVID-19.MethodsIn this nationwide retrospective observational study, patients in Tunisia diagnosed with COVID-19 between the 2nd of March and the 16th of May 2020 were contacted by telephone. We collected demographic and clinical data and specified characteristics and evolution of main neurological symptoms.ResultsOf 1034 confirmed COVID-19 patients, 646 were included (mean age 42.17 years old) and 466 (72.1%) had neurological symptoms. Neurological symptoms were isolated 22.7% (n = 106). Headache was the most frequent neurological symptom (n = 279, 41.1%): mainly frontotemporal (n = 143, 51.1%) and mild or moderate (n = 165, 59.1%). When associated with fever (n = 143, 51.3%), headache was more likely to be severe and present at onset. Recovery was reported in 83.2%. Smell and taste impairment were found in 37.9% (n = 245) and 36.8% (n = 238) respectively. Among them, 65.3% (156/239) were anosmic and 63.2% (146/231) were ageusic. A complete improvement was found in 72.1% (174/240) of smell impairment and in 76.8% (179/233) of taste impairment. Myalgia (n = 241, 37.3%) and sleep disturbances (n = 241, 37.3%) were also frequent. Imported cases had more neurological symptoms (p = 0.001). In 14.5%, neurological symptoms preceded the respiratory signs (RS). RS were associated with more frequent (p = 0.006) and numerous (p < 0.001) neurological symptoms.ConclusionsNeurological symptoms in COVID-19 are frequent, can be isolated and present at onset. A total recovery is the most recorded outcome. RS are predictive of neurological symptoms. Studies in to virus and host genetics should be considered to understand the different phenotypes.
Bioethanol Production from Date Seed Cellulosic Fraction Using Saccharomyces cerevisiae
This study investigates the feasibility of producing ethanol from date palm seeds. The chemical compositions of three varieties of date seeds were first studied, showing mainly the presence of cellulose and hemicellulose. Ethanol was produced after a pre-treatment of date seeds using acid hydrolysis to extract the cellulosic fraction and to remove the lignin. Producing ethanol by fermentation was performed using the yeast Saccharomyces cerevisiae for 24 h, during which ethanol yield, biomass concentration, and total reducing sugars were recorded. The results obtained showed that the sugar content decreased over time, while ethanol production increased. Indeed, date seeds gave the highest ethanol concentration of 21.57 g/L after 6 h of alcoholic fermentation. These findings proved the feasibility of producing ethanol from date seeds.
Atypical parkinsonian syndromes in a North African tertiary referral center
Introduction Data on epidemiology of atypical parkinsonian syndromes (APS) in North African countries are limited. Our objective was to study the epidemiological features of APS in a Tunisian population. Methods We conducted a 17‐year retrospective cross‐sectional descriptive study in the Department of Neurology at Razi University Hospital. We included all patients responding to consensus diagnosis criteria of APS. We recorded demographic and clinical data. Group differences were assessed with a post hoc ANOVA with a Bonferroni error correction. Results We included 464 APS patients. Hospital prevalence of APS among all parkinsonism cases was 20.6%. Mean annual increase of incidence defined as newly diagnosed APS cases per year reached 38.8%/year. APS were divided into 4 etiological subgroups: dementia with Lewy bodies (DLB; 56.7%); progressive supranuclear palsy(PSP; 16.2%); multiple system atrophy (MSA; 14.6%); and finally corticobasal syndrome (CBS; 12.5%). Sex‐ratio was 1.2. This male predominance was found in all subgroups except MSA (p = .013). Mean age at onset was 68.5 years, most belated in DLB (69.7 years; p < .001). Young‐onset parkinsonism (<40 years) was found only in MSA subgroup (p = .031). Parkinsonism was of late onset (>70 years) in 50.7% of patients and was significantly associated with DLB subgroup (p = .013). Inaugural parkinsonism was associated with CBS and MSA (p = .0497), and gait disorders at disease onset were associated with PSP and MSA (p = .0062). Cognitive and mood disorders were more marked in DLB and most preserved in MSA. Consanguinity was more marked in CBS (p = .037), and family history of dementia and psychiatric diseases was more common in DLB. Thirty‐seven families with similar cases of APS were identified. Conclusions This is the largest African epidemiological study on APS. In our population, APS were frequent and dominated by DLB. The age of onset of parkinsonism was the most decisive feature for differential diagnosis. In this paper, we described the largest cohort of atypical parkinsonian syndromes (APS) ever reported in both sub‐Saharan and North African countries comprising 464 Tunisian patients with APS. In our population, APS were frequent and dominated by DLB. The age of onset of parkinsonian syndrome was the most decisive feature for differential diagnosis.
Incorporation of multilayered double hydroxides/sepiolite augments proton conductivity performance in low sulfonated polyether sulfone octyl sulfonamide
Low-sulfonation-level polyether sulfone octyl sulfonamide (LSPSO) was blended with a layered double hydroxides (LDHs, Mg2AlCl)/sepiolite nanostructure clay as a filler to create an electrolyte membrane for fuel cell applications. Comprehensive characterization of the composite membranes was conducted, encompassing Fourier-transform infrared spectroscopy, X-ray diffraction, mechanical stability assessment, thermal gravimetric analysis, ion exchange capability, swelling characteristics, water uptake performance, and electrochemical impedance spectroscopy analysis. In comparison to the pristine LSPSO membrane, the presence of LDHs/sepiolite nanoarchitecture material within LSPSO exhibited superior water retention and proton conductivity values, especially at elevated temperatures. The proton conductivity of the composite membranes reached approximately 250 mS/cm, while the unmodified LSPSO membrane only achieved 35 mS/cm at 100 °C. Moreover, LSPSO composite membranes demonstrated enhanced chemical and thermal stability along with higher proton conductivity when compared to pristine LSPSO membranes. These findings highlight the potential of developing tailored LSPSO composite membranes to advance the prospects of commercial applications in proton exchange membrane fuel cells.
Significant augmentation of proton conductivity in low sulfonated polyether sulfone octyl sulfonamide membranes through the incorporation of hectorite clay
An innovative methodology was employed to fabricate ion exchange membranes tailored for fuel cell applications. This approach entailed blending low sulfonated polyether sulfone octyl sulfonamide (LSPSO) with Hectorite (Hect) clay at varying weight percentages (1 wt%, 3 wt%, and 6 wt%). The resultant composite membranes underwent comprehensive characterization via Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis, aiming to assess their surface morphology and thermal resilience. Remarkably, the thermal stability of the composite membrane exhibited a substantial enhancement in comparison to the pristine LSPSO membrane. Moreover, the incorporation of 6 wt% Hectorite into the composite membrane yielded a noteworthy amplification in proton conductivity, achieving a fourfold increase (141.66 mS/cm) as opposed to the LSPSO membrane in isolation (35.04 mS/cm). Consequently, the Hect/LSPSO composite membrane exhibits remarkable potential as an electrolyte membrane for fuel cells operating at temperatures surpassing 100 °C.
Seasonal Variation in Patch Test Results with European Baseline Series
Aim. To study the influence of season on patch tests results. Methods. We conducted a retrospective epidemiological study which concerned all the patients of the Tunisian center, who consulted in the Dermato-Allergology Unit of Occupational Medicine Department of Farhat Hached University Hospital-Sousse (Tunisia) over a period of 07 years. All the patients were tested by the European Standard Battery allergens (BSE). Results. The data of 1000 patch tests were analyzed during the study period. More than half of the patch tests (58.6%) was positive. In winter, 63% of patch tests showed a positive reaction versus 52% of patch tests in summer without a statistically significant association. However, results of lanolin alcohols, epoxy resin, and Sesquiterpene lactone mix varied significantly with season. Atopy was significantly associated with 18.8% of positive reactions in winter and only with 5.2% of positive reactions in summer (p=0.015). Conclusion. Seasonal variations in patch tests results were more significant with some allergens of European Standard Battery and in atopic patients.