Drogue, violence et résilience : consommateurs de drogue en cure et anciens délinquants violents à Dakar.

In Senegal, violent delinquency and illicit drug use are on the increase. This study focuses on two distinct groups: drug users (DUs) undergoing rehabilitation and violent ex-offenders (VEs). The methodology adopted includes a quantitative survey of the general population (n=1009), followed by a qualitative survey of fifteen participants, including eight DUs undergoing treatment at the Centre de prise en charge intégrée des addictions de Dakar (CEPIAD) (Integrated Addictions Management Center of Dakar) and the Centre Jacques Chirac de Thiaroye, and seven former VEs from the Grand Yoff district. This neighborhood, known for its violence, is juxtaposed with the Grand Yoff social housing estate, a residential area also affected by outbreaks of violence. This study aims to establish the link(s) between drug use and criminal violence by analyzing the life stories of young adults who have managed to leave drug use and delinquency behind. It then looks to identify the determinants of resilience in certain young people. The study revealed delinquent violence among young people does not systematically result from drug use. Rather, drug use is a factor conducive to violence. The links between drugs and violence depend on individual predisposition, the type of drugs used, and the level of addiction. Resilience results from a web of individual, sociocultural, and environmental factors. It is not static, but rather the result of a series of successes, failures, and even relapses.

ASSESSMENT OF OCCUPATIONAL EXPOSURE TO EXTERNAL RADIATION AMONG WORKERS OF THREE COMMUNITY HOSPITALS IN SENEGAL.

Occupational radiation doses of 602 medical workers from the departments of Radiology, Thoracic and cardiovascular surgery, Operating room, Nuclear medicine, Radiotherapy and cardiology were evaluated during 2017 to 2021 in three hospitals in Senegal. Each hospital was subdivided into various occupational groups. Whole-body doses Hp(10), local skin doses Hp(0.07) and annual collective dose Hp(10) were measured by OSL (optically stimulated luminescence) dosimetry. The occupational groups with the highest radiation exposures, ~0.185 mSv in 1 y, were in the field of nuclear medicine, radiology, cardiology, Thoracic and cardiovascular surgery and Operating room. All results of the measured annual effective dose were below the ICRP (International Commission on Radiological Protection) dose limits of 20 mSv/y, averaged over any 5-y period.

Investigating the influence of freezing rate and frozen storage conditions on a model sponge cake using synchrotron X-rays micro-computed tomography.

Synchrotron X-rays micro-computed tomography was applied to visualize and quantify 3D ice crystal changes into a model sponge cake after freezing and subsequent frozen storage. Model sponge cake samples were submitted to two different freezing rates (fast: 17.2 °C min-1 and slow: 0.3 °C min-1), then stored at constant and fluctuating temperatures over a two weeks period. 3D images were acquired at frozen state thanks to a thermostated cell (CellStat) and processed using a grey level based segmentation method. Image analysis revealed that the ice volume fraction is conserved during storage but ice crystal size and location change whatever the freezing rate and the storage conditions. Maximum local thicknesses increase both inside (from 20 µm to 50 µm) and outside (from 47 µm to 70 µm) the matrix during the fourteen days storage period. Both specific surface areas between starch and ice (SSAice/starch) and between air and ice (SSAair/ice) also evolve with storage duration: SSAice/starch decreases up to - 30 % while SSAair/ice increases up to + 13 % depending on the freezing rates and the storage conditions. These results highlighted that, during storage, ice crystals evolve according to two different mechanisms depending on the freezing rate: fast freezing leads to a local redistribution of water both within the starch matrix and within the pores, while slow freezing results in both local redistribution within the starch matrix and water migration towards the pores. In addition, stable storage temperatures favor local water redistribution whereas water migration from the starch matrix towards the pores was greater in the case of fluctuating storage temperatures. This study shows that freezing and frozen storage conditions have a synergistic effect on the microstructure evolution of sponge cake due to recrystallization phenomena.

3D Characterization of Sponge Cake as Affected by Freezing Conditions Using Synchrotron X-ray Microtomography at Negative Temperature.

In this study, the microstructural evolution of a non-reactive porous model food (sponge cake) during freezing was investigated. Sponge cake samples were frozen at two different rates: slow freezing (0.3 °C min-1) and fast freezing (17.2 °C min-1). Synchrotron X-ray microtomography (µ-CT) and cryo-scanning electron microscopy (Cryo-SEM) were used to visualize and analyze the microstructure features. The samples were scanned before and after freezing using a specific thermostated cell (CellStat) combined with the synchrotron beamline. Cryo-SEM and 3D µ-CT image visualization allowed a qualitative analysis of the ice formation and location in the porous structure. An image analysis method based on grey level was used to segment the three phases of the frozen samples: air, ice and starch. Volume fractions of each phase, ice local thickness and shape characterization were determined and discussed according to the freezing rates.

Delivering Vitamin A Supplements to Children Aged 6-59 Months: Comparing Delivery through Campaigns and through Routine Health Services in Senegal.

BACKGROUND: Using twice-yearly campaigns such as Child Health Days to deliver vitamin A supplements has been a key strategy over the last 2 decades, and was an important component in helping reach the Millennium Development Goals in child health. As countries move to strengthen their routine health services under the Sustainable Development Goals, efforts are underway to shift supplementation from campaign to routine delivery. OBJECTIVE: The aim of this study was to compare cost, coverage, and user satisfaction between twice-yearly campaigns and routine delivery of vitamin A supplements in Senegal. METHODS: Information was collected on cost, coverage, and user satisfaction with both types of delivery, using administrative data, interviews at various levels in the health system, and focus group discussions with caregivers. Both qualitative and quantitative information were obtained, for 2 regions using routine delivery and 2 regions using campaign delivery. RESULTS: Routine delivery receives fewer dedicated resources. Coverage is lower, especially of children >12 mo of age. Districts undertake outreach ("mini-campaigns") to try to improve coverage in regions using routine delivery, in effect using a hybrid approach. Some mothers prefer the administration of supplements at a health facility as it is perceived as more hygienic and involving professional health workers, but others, especially those living further away, prefer house-to-house delivery which was the norm for the campaign mode. CONCLUSIONS: Advance planning for the shift to routine delivery is important in maintaining coverage, as is strengthening the primary health care system by having an appropriate ratio of salaried workers to population. When the system relies heavily on volunteers, and the small incentive payments to volunteers are discontinued, coverage suffers. Routine delivery also relies on good record-keeping and hence literacy. Community understanding of, and support for, supplementation are even more important for routine than for campaign delivery.

Effect of neighboring cells on cell stiffness measured by optical tweezers indentation.

We report on the modification of mechanical properties of breast cancer cells when they get in contact with other neighboring cells of the same type. Optical tweezers vertical indentation was employed to investigate cell mechanics in isolated and contact conditions, by setting up stiffness as a marker. Two human breast cancer cell lines with different aggressiveness [MCF-7 (luminal breast cancer) and MDA-MB-231 (basal-like breast cancer)] and one normal immortalized breast cell line HBL-100 (normal and myoepithelial) were selected. We found that neighboring cells significantly alter cell stiffness: MDA-MB-231 becomes stiffer when in contact, while HBL-100 and MCF-7 exhibit softer character. Cell stiffness was probed at three cellular subregions: central (above nucleus), intermediate (cytoplasm), and near the leading edge. In an isolated condition, all cells showed a significant regional variation in stiffness: higher at the center and fading toward the leading edge. However, the regional variation becomes statistically insignificant when the cells were in contact with other neighboring cells. The proposed approach will contribute to understand the intriguing temporal sequential alterations in cancer cells during interaction with their surrounding microenvironment.

Phylogeny of nodulation genes and symbiotic diversity of Acacia senegal (L.) Willd. and A. seyal (Del.) Mesorhizobium strains from different regions of Senegal.

Acacia senegal and Acacia seyal are small, deciduous legume trees, most highly valued for nitrogen fixation and for the production of gum arabic, a commodity of international trade since ancient times. Symbiotic nitrogen fixation by legumes represents the main natural input of atmospheric N2 into ecosystems which may ultimately benefit all organisms. We analyzed the nod and nif symbiotic genes and symbiotic properties of root-nodulating bacteria isolated from A. senegal and A. seyal in Senegal. The symbiotic genes of rhizobial strains from the two Acacia species were closed to those of Mesorhizobium plurifarium and grouped separately in the phylogenetic trees. Phylogeny of rhizobial nitrogen fixation gene nifH was similar to those of nodulation genes (nodA and nodC). All A. senegal rhizobial strains showed identical nodA, nodC, and nifH gene sequences. By contrast, A. seyal rhizobial strains exhibited different symbiotic gene sequences. Efficiency tests demonstrated that inoculation of both Acacia species significantly affected nodulation, total dry weight, acetylene reduction activity (ARA), and specific acetylene reduction activity (SARA) of plants. However, these cross-inoculation tests did not show any specificity of Mesorhizobium strains toward a given Acacia host species in terms of infectivity and efficiency as stated by principal component analysis (PCA). This study demonstrates that large-scale inoculation of A. senegal and A. seyal in the framework of reafforestation programs requires a preliminary step of rhizobial strain selection for both Acacia species.

Impact of rhizobial inoculation on Acacia senegal (L.) Willd. growth in greenhouse and soil functioning in relation to seed provenance and soil origin.

Rhizobial inoculation has a positive impact on plants growth; however, there is little information about its effect on soil microbial communities and their activity in the rhizosphere. It was therefore necessary to test the effect of inoculation of Acacia senegal (L.) Willd. seedlings with selected rhizobia on plant growth, structure and diversity of soil bacterial communities and soil functioning in relation to plant provenance and soil origin. In order to carry out this experiment, three A. senegal seeds provenance from Kenya, Niger, and Senegal were inoculated with selected rhizobial strains. They have been further grown during 4 months in greenhouse conditions in two non-disinfected soils, Dahra and Goudiry coming respectively from arid and semi-arid areas. The principal component analysis (ACP) showed an inoculation effect on plant growth, rhizospheric bacterial diversity and soil functioning. However, the performances of the rhizobial strains varied in relation to the seed provenance and the soil origin. The selected rhizobial strains, the A. senegal provenance and the soil origin have modified the structure and the diversity of soil bacterial communities as measured by principal component analysis/denaturing gradient gel electrophoresis analyses. It is interesting to note that bacterial communities of Dahra soil were highly structured according to A. senegal provenance, whereas they were structured in relation to rhizobial inoculation in Goudiry soil. Besides, the impact of inoculation on soil microbial activities measured by fluorescein diacetate analyses varied in relation to plant provenance and soil origin. Nevertheless, total microbial activity was about two times higher in Goudiry, arid soil than in Dahra, semi-arid soil. Our results suggest that the rhizobial inoculation is a suitable tool for improving plants growth and soil fertility. Yet, the impact is dependent on inoculants, plant provenance and soil origin. It will, therefore, be crucial to identify the appropriate rhizobial strains and plant provenance or species in relation to the soil type.