Effect of ceria on the organization and bio-ability of anatase fullerene-like crystals

The nanostructure and the oxygen storage capacity against reactive oxygen species (ROS) are essential features to take into account during the design of a new material that will be used as the basis of novel therapeutic technologies. Here we evaluate the incorporation of nano-ceria, which has a demonstrated ability to scavenge free radicals under physiological conditions comparable to those observed for superoxide dismutase and catalase, to TiO2 crystalline assemblies. The material was planned to merge the scavenging properties of CeO2 on a specifically designed structured TiO2 substrate. The presence of Ce atoms has a clear influence in the materials' morphologies, distorting anatase crystal lattice and inducing the formation of fullerene-like structures. The cytotoxicity of the materials against L929 fibroblasts after 24 hours of cell culture was evaluated. Both structural and oxidative properties of the materials have a clear effect on fibroblast viability; in fact it was demonstrated that cellular proliferation can be modulated varying the Ce3+/Ti4+ molar ratio.Fil: Gravina, Noel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Ruso, Juan Manuel. Universidad de Santiago de Compostela; EspañaFil: Mbeh, Doris Antoinette. École Polytechnique De Montréal; CanadáFil: Yahia, L'Hocine. École Polytechnique De Montréal; CanadáFil: Merhi Yahye. University Of Montreal; CanadáFil: Sartuqui, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Messina, Paula Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentin

Biocompatibilité des complexes protéines–nanoparticules : perspectives sur la réponse cellulaire aux nanoparticules d’oxyde de fer fonctionnalisées, revêtues d’un corona

RÉSUMÉ Cette thèse rapporte l'étude de la biocompatibilité des nanoparticules (NPs) d‟oxyde de fer (Fe3O4) superparamagnetiques candidates à une livraison ciblée des molécules thérapeutiques. Nous nous sommes tout spécialement attachés à étudier l'impact de la composition de surface de ces NPs et l'adsorption des protéines à la surface de ces dernières sur les réponses cellulaires. Pour ce faire, nous avons tout d'abord examiné le potentiel toxique la magnétite avec divers fonctionnalisations : celle qui est préparée avec (1) une monocouche d'acide oléique (Fe3O4@OA), qui est ensuite converti en (2) une enveloppe de silane contenant une amine (Fe3O4@NH2), (3) un revêtement de silice (Fe3O4@SiO2), et (4) une enveloppe de silane contenant une amine sur un revêtement de silice (Fe3O4@SiO2@NH2). La présence de ces groupements à la surface des NPs a été confirmée par l'analyse XPS et la microscopie électronique à transmission (TEM). Nous avons pu prouver que le potentiel toxique des NPs est dose-dépendant et ainsi déterminer les doses biocompatibles pour chaque fonctionnalisation de surface. L'observation au microscope de la morphologie des cellules exposées aux NPs, leur activité mitochondriale et proinflammatoire ont montré que, en plus des caractéristiques de surface, le milieu de culture cellulaire influence également la cytotoxicité des NPs. Ces résultats montrent clairement que pour pouvoir utiliser nos NPs comme nanovecteur pharmaceutique de façon sécuritaire, nous devons contrôler la fonctionnalisation de surface et l'interaction dynamique entre la NP et le milieu physiologique dans lequel elle est suspendue. Pour comprendre l'interaction entre la NP et le milieu de culture, dans une première étape, nous avons utilisé trois milieux de culture différents à savoir : DMEM, F-12K et DMEM/F12 (voir annexe A) et la magnétite sans revêtement (Fe3O4). Ces milieux ont été enrichis soit avec le sérum bovin (voir annexe B) soit avec un sérum synthétique (SFMS). Nous avons prouvé la présence d'une couronne protéique (corona) sur les NPs suspendues dans les milieux de culture enrichis de sérum bovin. Nous avons également démontré que la formation du corona sur les nanoparticules d'oxyde de fer superparamagnétiques (SPIONs) dépend de la composition du milieu de culture et que le potentiel cytotoxique des NPs est influencé par l'interaction NP-protéines.----------ABSTRACT This thesis presents the study of the biocompatibility of nanoparticles (NPs) of iron oxide (Fe3O4) candidates for targeted delivery of therapeutic molecules. We especially devoted to study the impact of the surface composition of the NPs and protein adsorption at the surface thereof on the cellular responses. To do this, we first examined the toxic potential of magnetite with various functionalizations: one that is prepared with (1) a monolayer of oleic acid (Fe3O4@OA), which is then converted to (2) an envelope silane containing an amine (Fe3O4@NH2), (3) a coating of silica (Fe3O4@SiO2), and (4) an envelope containing a silane coating on amine silica (Fe3O4@SiO2@NH2). The presence of these groups at the surface of the NPs was confirmed by XPS and transmission electron microscopy (TEM) analysis. We were able to prove that the toxic potential of NPs is dose-dependent and we determine the biocompatible doses for each surface functionalization. Microscopic observation of the morphology of the cells exposed to NPs, and their proinflammatory and mitochondrial activity showed that, in addition to surface features, the cell culture medium also affect the cytotoxicity of the NPs. These results clearly show that in order to use our NPs as pharmaceutical nanocarrier safely, we need to control the surface functionalization and the dynamic interaction between the NP and the physiological environment in which it is suspended. To understand the interaction between the NP and the culture medium, as a first step, we used three different culture media namely: DMEM, F-12K and DMEM / F12 (see Appendix A) and uncoated magnetite (Fe3O4). These media were enriched with either fetal bovine serum (see Appendix B) or with a synthetic serum (SFMS). We have proved the presence of a protein corona on NPs suspended in culture media enriched with bovine serum. We also demonstrated that the formation of the corona depends on the composition of the culture medium and that the cytotoxic potential of the NPs is influenced by NP-protein interaction. In a second step, we used one culture medium (DMEM / F12) and the magnetite with three different surface compositions: uncoated SPIONs with hydroxyl groups (OH) on the surface; coated SPIONs with an amine group (NH2) on the surface and the last one with a carboxylic group (COOH) on the surface. The results show that the composition of the corona dependst o

IRAN’S NUCLEAR POLICY: NATURE, AMBITION, AND STRATEGY

Nuclear, chemical, and biological weapons represent the biggest danger to humanity. During the Cold War, the US and USSR provided ‘umbrella protection’ to convince allies not to acquire nuclear weapons. Most ‘newly’ independent nations never had such security during the Cold War since they were not part of a power bloc. During the Iran-Iraq conflict (1980-1988), the Islamic Republic of Iran was attacked with chemical weapons. Since Mujahedin-e-Khalq (MEK), an Iranian exile organization, exposed Iran's hidden nuclear program in 2002, the topic has gained worldwide attention. Iran's nuclear agenda has produced a worldwide catastrophe despite its NPT membership. Iran says its nuclear program is peaceful and respects Islamic values. Most US politicians and academics consider Iran a rough nation with political and strategic concerns, including regional hegemony, human rights, terrorism, WMD proliferation, and military operations beyond the border. This study examines Iran's nuclear policies to demonstrate its essence, goal, and strategy.      &nbsp

Protein corona and nanoparticles: How can we investigate on?

Nanoparticles (NPs) represent one of the most promising tools for drug-targeting and drug-delivery. However, a deeper understanding of the complex dynamics that happen after their in vivo administration is required. Particularly, plasma proteins tend to associate to NPs, forming a new surface named the 'protein corona' (PC). This surface is the most exposed as the 'visible side' of NPs and therefore, can have a strong impact on NP biodistribution, targeting efficacy and also toxicity. The PC consists of two poorly delimited layers, known as 'hard corona' (HC) and 'soft corona' (SC), that are affected by the complexity of the environment and the formed protein-surface equilibrium during in vivo blood circulation. The HC corona is formed by proteins strongly associated to the NPs, while the SC is an outer layer consisting of loosely bound proteins. Several studies attempted to investigate the HC, which is easier to be isolated, but yielded poor reproducibility, due to varying experimental conditions. As a consequence, full mapping of the HC for different NPs is still lacking. Moreover, the current knowledge on the SC, which may play a major role in the 'first' interaction of NPs once in vivo, is very limited, mainly due to the difficulties in preserving it after purification. Therefore, multi-disciplinary approaches leading to the obtainment of a major number of information about the PC and its properties is strongly needed to fully understand its impact and to better support a more safety and conscious application of nanotechnology in medicine

Correlates of Out-of-Pocket and Catastrophic Health Expenditures in Tanzania: Results from a National Household Survey.

Inequality in health services access and utilization are influenced by out-of-pocket health expenditures in many low and middle-income countries (LMICs). Various antecedents such as social factors, poor health and economic factors are proposed to direct the choice of health care service use and incurring out-of-pocket payments. We investigated the association of these factors with out-of-pocket health expenditures among the adult and older population in the United Republic of Tanzania. We also investigated the prevalence and associated determinants contributing to household catastrophic health expenditures. We accessed the data of a multistage stratified random sample of 7279 adult participants, aged between 18 and 59 years, as well as 1018 participants aged above 60 years, from the first round of the Tanzania National Panel survey. We employed multiple generalized linear and logistic regression models to evaluate the correlates of out-of-pocket as well as catastrophic health expenditures, accounting for the complex sample design effects. Increasing age, female gender, obesity and functional disability increased the adults' out-of-pocket health expenditures significantly, while functional disability and visits to traditional healers increased the out-of-pocket health expenditures in older participants. Adult participants, who lacked formal education or worked as manual laborers earned significantly less (p < 0.001) and spent less on health (p < 0.001), despite having higher levels of disability. Large household size, household head's occupation as a manual laborer, household member with chronic illness, domestic violence against women and traditional healer's visits were significantly associated with high catastrophic health expenditures. We observed that the prevalence of inequalities in socioeconomic factors played a significant role in determining the nature of both out-of-pocket and catastrophic health expenditures. We propose that investment in social welfare programs and strengthening the social security mechanisms could reduce the financial burden in United Republic of Tanzania

Webportal Applications: Automated Student Clearance Portal

Web portals are often designed to provide access to information from diverse sources in a uniform manner. This paper presents the development of a specialized portal designed to be used by graduating students to undertake clearance processes from the different departments after their studies in the university. Traditional Clearance forms are provided by university institutions to graduating students, which have to be taken in hard copy to the different offices for signing and when duly signed, confirms that the student has fulfilled all requirements and is not indebted to any of the departments or units that the student was associated with within the institution. This approach has been found to be time consuming as the students have to physically visit each office.The development of a portal based approach provides portal access to the authorized officers to access the students’ clearance page and clear the student without the student needing to visit the officer. This system is configured to send email reminders and is also interfaced with the GSM-SMS system to send alerts to both the officer required to do the clearance and the student. The portal was developed using the HTML and PHP packages while the database was implemented using the MySQL database package

Work-Family Conflict and Stress: A Triangulated Analysis of the Plight of Working Mothers in Nigerian Universities

This study investigated the plight of working mothers of children under the age of 18 at the University of Nigeria within the context of work-family conflict, using data from a cross-sectional sample of 485 academic and non-academic staff selected through a multi-staged sampling technique. Data were obtained using questionnaires and seven IDI (in-depth interview) respondents. Data were analyzed using descriptive statistics such as percentages and frequency tables, while the Chi-square was used to examine the study variables. The results indicated that there is a statistically significant relationship between couples living together and the stress experience of working mothers with under-age children. The findings further show that there is a statistically significant relationship between the staff category of working mothers and the experience of stress. This underscored the recommendation that the government needs to review the working conditions of women and support workplace policies that allow flexibility and support for working mothers. Social workers are also recommended to be involved in some government and organization policies that will help to reduce work overload for working mothers