Immunopurification and characterization of a rape (Brassica napus L.) seedling lipase

Lipase or triacylglycerol acylhydrolase (E.C.3.1.1.3) was purified to homogeneity from rapeseed-germinated cotyledons (Brassica napus L.). The purification scheme involved homogenization, centrifugation, ultracentrifugation and affinity chromatography using polyclonal antibodies raised against porcine pancreatic lipase. The purified rapeseed lipase was homogenous and did not contain contaminating proteins detectable by SDS-PAGE and HPLC analysis. The specific activity of the purified preparation was increased about 1950 times, with an overall yield of 35%. The rapeseed lipase was found to be a cytosoluble, glycosylated and heat-labile serine-hydrolase. It was monomeric with a molecular mass of 38 kDa and a pH of 6.6. The purification method used in the present work is rapid, simple, and yields highly purified lipase. It may therefore be applicable in the purification of other uncharacterized plant lipases.Keywords: Brassica napus L., immuno-affinity, lipase, purification, triacylglycerol acyl hydrolaseAfrican Journal of Biotechnology Vol. 12(21), pp. 3224-323

Forced degradation study of quinapril by UPLC-DAD and UPLC/MS/MS: Identification of by-products and development of degradation kinetics.

International audienceQuinapril undergoes a significant degradation in the solid state, specially in the presence of humidity, temperature and pharmaceutical excipients. Since dissolution increases the degradation, hydrolytic reactions are among the most common processes involved in drug degradation. Improving the knowledge regarding drug stability, particularly concerning the critical factors that can influence the stability of the active substance in solutions, such as the temperature, the pH and the concentration of catalytic species usually acids or bases are essential for pharmaceutical use. The aim of this study was therefore to develop a new chromatographic method for rapidly and accurately assessing the chemical stability of quinapril and to study the mechanism of quinapril degradation in acidic, neutral and alkaline media at 80°C according to the ICH guidelines. Ultra High Performance Liquid Chromatography (UPLC) coupled with electrospray ionization tandem mass spectrometry and/or diode array detector was used for the rapid and simultaneous analysis of quinapril and its by-products. Separation was achieved using a BEH C18 column and a mixture of acetonitrile-ammonium hydrogencarbonate buffer (pH 8.2; 10 mM) (65:35, v/v) at a flow rate of 0.4 mL/min as a mobile phase. This method allowed drug byproducts profiling, identification, structure elucidation and quantitative determination under stress conditions. The developed method also provides the determination of the kinetic rate constants for the degradation of quinapril and the formation of its major by-products. A complete model including degradation pathway observed under all tested conditions was proposed according to the kinetic study and the structure elucidation of by-products

Correlation anatomo-scannographique dans le cancer du larynx

Introduction : Le but de la chirurgie du larynx est de conserver dans la mesure du possible un larynx fonctionnel tout en répondant aux impératifs carcinologiques. Les limites d'extension tumorale doivent être finement analysées en pré-opératoire pour adopter la technique opératoire appropriée. dans ce domaine, l'apport de la TdM est incontestable pour l'étude de cette extension en profondeur.Patients et méthodes : il s'agit d'une étude rétrospective des dossiers de 43 patients explorés et traités respectivement aux services d'imagerie médicale et d'ORL de l'hôpital Tahar Sfar de Mahdia sur une période de 14 ans entre Janvier 1995 et décembre 2008.Résultats : La classification pré-opératoire des tumeurs pharyngo-laryngées est plus fiable en se basant à la fois sur l’endoscopie et la TdM que sur l’endoscopie seule. La fiabilité de cette association était de 76%. L'étude de certaines zones dites d'intérêt a montré une efficacité de 72% pour l'atteinte de la commissure antérieure, de 79% pour les bandes ventriculaires, de 81% pour la sous glotte, de 88% pour la loge HTE, de 83% pour les espaces para-glottiques et de 79% pour les cartilages. Nos résultats étaient concordants à ceux de la littérature.Discussion et conclusion : la TdM constitue une partie intégrante du bilan préopératoire des cancers du pharyngolarynx. Elle précise l'extension tumorale en profondeur aux espaces graisseux, aux cartilages et aux tissus extralaryngés. L’analyse fine des images tomodensitométriques permet donc d’orienter la décision thérapeutique.Mots clés : cancer, larynx, anatomopathologie, chirurgie

Service Quality Towards Retail Stores on Expected and Perceived Service Quality

Purpose: The purpose of this research is to investigate the relationship between expected service quality and perceived service quality in retail stores.   Theoretical framework: The study will be based on the Servqual model, which measures service quality by assessing the gap between expected and perceived service.   Design/methodology/approach: The research will be conducted using a survey method. A sample of customers from various retail stores will be asked to rate their expected and perceived service quality. The data will be analyzed using statistical techniques to determine the relationship between the two variables.   Findings: The findings of the study will show the extent to which customers' expectations are met by retail stores in terms of service quality. The results will also indicate areas where retailers need to improve in order to meet customers' expectations.   Research, practical and social implications: The research will provide insight into how retailers can improve their service quality to meet customers' expectations. The findings will also be useful for retailers in developing strategies to improve customer satisfaction and loyalty. The results will also have practical implications for customers in terms of their expectations and perceptions of service quality.   Originality/value: This research paper is of immense value as it depicts the real-life service qualities that have been provided and the perceived quality of service. The wide variety of service quality and commitment of the employees to the customers and stores are also crucial (Liebrechtet al. 2021). The real-life examples are of immense significance as customer service is the need of the hour, applicable at any part of the world. Moreover, this paper has its originality by bringing forth the effectiveness of retail customer service and management of the same

Towards securing machine learning models against membership inference attacks

From fraud detection to speech recognition, including price prediction, Machine Learning (ML) applications are manifold and can significantly improve different areas. Nevertheless, machine learning models are vulnerable and are exposed to different security and privacy attacks. Hence, these issues should be addressed while using ML models to preserve the security and privacy of the data used. There is a need to secure ML models, especially in the training phase to preserve the privacy of the training datasets and to minimise the information leakage. In this paper, we present an overview of ML threats and vulnerabilities, and we highlight current progress in the research works proposing defence techniques against ML security and privacy attacks. The relevant background for the different attacks occurring in both the training and testing/inferring phases is introduced before presenting a detailed overview of Membership Inference Attacks (MIA) and the related countermeasures. In this paper, we introduce a countermeasure against membership inference attacks (MIA) on Conventional Neural Networks (CNN) based on dropout and L2 regularization. Through experimental analysis, we demonstrate that this defence technique can mitigate the risks of MIA attacks while ensuring an acceptable accuracy of the model. Indeed, using CNN model training on two datasets CIFAR-10 and CIFAR-100, we empirically verify the ability of our defence strategy to decrease the impact of MIA on our model and we compare results of five different classifiers. Moreover, we present a solution to achieve a trade-off between the performance of the model and the mitigation of MIA attack

Longitudinal changes in functional connectivity of cortico-basal ganglia networks in manifests and premanifest huntington's disease

Huntington's disease (HD) is a genetic neurological disorder resulting in cognitive and motor impairments. We evaluated the longitudinal changes of functional connectivity in sensorimotor, associative and limbic cortico-basal ganglia networks. We acquired structural MRI and resting-state fMRI in three visits one year apart, in 18 adult HD patients, 24 asymptomatic mutation carriers (preHD) and 18 gender- and age-matched healthy volunteers from the TRACK-HD study. We inferred topological changes in functional connectivity between 182 regions within cortico-basal ganglia networks using graph theory measures. We found significant differences for global graph theory measures in HD but not in preHD. The average shortest path length (L) decreased, which indicated a change toward the random network topology. HD patients also demonstrated increases in degree k, reduced betweeness centrality bc and reduced clustering C. Changes predominated in the sensorimotor network for bc and C and were observed in all circuits for k. Hubs were reduced in preHD and no longer detectable in HD in the sensorimotor and associative networks. Changes in graph theory metrics (L, k, C and bc) correlated with four clinical and cognitive measures (symbol digit modalities test, Stroop, Burden and UHDRS). There were no changes in graph theory metrics across sessions, which suggests that these measures are not reliable biomarkers of longitudinal changes in HD. preHD is characterized by progressive decreasing hub organization, and these changes aggravate in HD patients with changes in local metrics. HD is characterized by progressive changes in global network interconnectivity, whose network topology becomes more random over time. Hum Brain Mapp, 2016. © 2016 Wiley Periodicals, Inc

SLC26A11 (KBAT) in Purkinje Cells Is Critical for Inhibitory Transmission and Contributes to Locomotor Coordination

Chloride homeostasis determines the impact of inhibitory synaptic transmission and thereby mediates the excitability of neurons. Even though cerebellar Purkinje cells (PCs) receive a pronounced inhibitory GABAergic input from stellate and basket cells, the role of chloride homeostasis in these neurons is largely unknown. Here we studied at both the cellular and systems physiological level the function of a recently discovered chloride channel, SLC26A11 or kidney brain anion transporter (KBAT), which is prominently expressed in PCs. Using perforated patch clamp recordings of PCs, we found that a lack of KBAT channel in PC-specific KBAT KO mice (L7-KBAT KOs) induces a negative shift in the reversal potential of chloride as reflected in the GABAA-receptor- evoked currents, indicating a decrease in intracellular chloride concentration. Surprisingly, both in vitro and in vivo PCs in L7-KBAT KOs showed a significantly increased action potential firing frequency of simple spikes, which correlated with impaired motor performance on the Erasmus Ladder. Our findings support an important role for SLC26A11 in moderating chloride homeostasis and neuronal activity in the cerebellum

SLC26A11 (KBAT) in Purkinje Cells Is Critical for Inhibitory Transmission and Contributes to Locomotor Coordination

Chloride homeostasis determines the impact of inhibitory synaptic transmission and thereby mediates the excitability of neurons. Even though cerebellar Purkinje cells (PCs) receive a pronounced inhibitory GABAergic input from stellate and basket cells, the role of chloride homeostasis in these neurons is largely unknown. Here we studied at both the cellular and systems physiological level the function of a recently discovered chloride channel, SLC26A11 or kidney brain anion transporter (KBAT), which is prominently expressed in PCs. Using perforated patch clamp recordings of PCs, we found that a lack of KBAT channel in PC-specific KBAT KO mice (L7-KBAT KOs) induces a negative shift in the reversal potential of chloride as reflected in the GABAA-receptor-evoked currents, indicating a decrease in intracellular chloride concentration. Surprisingly, both in vitro and in vivo PCs in L7-KBAT KOs showed a significantly increased action potential firing frequency of simple spikes, which correlated with impaired motor performance on the Erasmus Ladder. Our findings support an important role for SLC26A11 in moderating chloride homeostasis and neuronal activity in the cerebellum