Study on the Powder-Spreading Process of Walnut Shell/Co-PES Biomass Composite Powder in Additive Manufacturing.

Powder laying is a necessary procedure during powder bed additive manufacturing (PBAM), and the quality of powder bed has an important effect on the performance of products. Because the powder particle motion state during the powder laying process of biomass composites is difficult to observe, and the influence of the powder laying process parameters on the quality of the powder bed is still unclear, a simulation study of the biomass composite powder laying process during powder bed additive manufacturing was conducted using the discrete element method. A discrete element model of walnut shell/Co-PES composite powder was established using the multi-sphere unit method, and the powder-spreading process was numerically simulated using two different powder spreading methods (rollers/scrapers). The results showed that the quality of powder bed formed by roller laying was better than that formed by scrapers with the same powder laying speed and powder laying thickness. For both of the two different spreading methods, the uniformity and density of the powder bed decreased as spreading speed increased, although the spreading speed had a more important influence on scraper spreading compared to roller spreading. As powder laying thickness increased, the powder bed formed by the two different powder laying methods became more uniform and denser. When the powder laying thickness was less than 110µm, the particles were easily blocked at the powder laying gap and are pushed out of the forming platform, forming many voids, and decreasing the powder bed's quality. When the powder thickness was greater than 140 µm, the uniformity and density of the powder bed increased gradually, the number of voids decreased, and the quality of the powder bed improved.

Management of uncomplicated malaria among children under five years at public and private sector facilities in Mali.

BACKGROUND: Prompt and effective malaria diagnosis and treatment is a cornerstone of malaria control. Case management guidelines recommend confirmatory testing of suspected malaria cases, then prescription of specific drugs for uncomplicated malaria and for severe malaria. This study aims to describe case management practices for children aged 1-59 months seeking treatment with current or recent fever from public and private, rural and urban health providers in Mali. METHODS: Data were collected at sites in Sikasso Region and Bamako. Health workers recorded key information from the consultation including malaria diagnostic testing and result, their final diagnosis, and all drugs prescribed. Children with signs of severe diseases were ineligible. Consultations were not independently observed. Appropriate case management was defined as both 1) tested for malaria using rapid diagnostic test or microscopy, and 2) receiving artemisinin combination therapy (ACT) and no other antimalarials if test-positive, or receiving no antimalarials if test-negative. RESULTS: Of 1602 participating children, 23.7% were appropriately managed, ranging from 5.3% at public rural facilities to 48.4% at community health worker sites. The most common reason for 'inappropriate' management was lack of malaria diagnostic testing (50.4% of children). Among children with confirmed malaria, 50.8% received a non-ACT antimalarial (commonly artesunate injection or artemether), either alone or in combination with ACT. Of 215 test-negative children, 44.2% received an antimalarial drug, most commonly ACT. Prescription of multiple drugs was common: 21.7% of all children received more than one type of antimalarial, while 51.9% received an antibiotic and antimalarial. Inappropriate case management increased in children with increasing axillary temperatures and those seeking care over weekends. CONCLUSIONS: Multiple limitations in management of febrile children under five were identified, including inconsistent use of confirmatory testing and apparent use of severe malaria drugs for uncomplicated malaria. While we cannot confirm the reasons for these shortcomings, there is a need to address the high use of non-ACT antimalarials in this context; to minimize potential for drug resistance, reduce unnecessary expense, and preserve life-saving treatment for severe malaria cases. These findings highlight the challenge of managing febrile illness in young children in a high transmission setting.

Measuring malaria diagnosis and treatment coverage in population-based surveys: a recall validation study in Mali among caregivers of febrile children under 5 years.

BACKGROUND: Nationally-representative household surveys are the standard approach to monitor access to and treatment with artemisinin-based combination therapy (ACT) among children under 5 years (U5), however these indicators are dependent on caregivers' recall of the treatment received. METHODS: A prospective case-control study was performed in Mali to validate caregivers' recall of treatment received by U5s when seeking care for fever from rural and urban public health facilities, community health workers and urban private facilities. Clinician-recorded consultation details were the gold standard. Consenting caregivers were followed-up for interview at home within 2 weeks using standard questions from Demographic and Health Surveys and Malaria Indicator Surveys. RESULTS: Among 1602 caregivers, sensitivity of recalling that the child received a finger/heel prick was 91.5%, with specificity 85.7%. Caregivers' recall of a positive malaria test result had sensitivity 96.2% with specificity 59.7%. Irrespective of diagnostic test result, the sensitivity and specificity of caregivers' recalling a malaria diagnosis made by the health worker were 74.3% and 74.9%, respectively. Caregivers' recall of ACT being given had sensitivity of 43.2% and specificity 90.2%, while recall that any anti-malarial was given had sensitivity 59.0% and specificity 82.7%. Correcting caregivers' response of treatment received using a combination of a visual aid with photographs of common drugs for fever, prescription documents and retained packaging changed ACT recall sensitivity and specificity to 91.5% and 71.1%, respectively. CONCLUSIONS: These findings indicate that caregivers' responses during household surveys are valid when assessing if a child received a finger/heel prick during a consultation in the previous 2 weeks, and if the malaria test result was positive. Recall of ACT treatment received by U5s was poor when based on interview response only, but was substantially improved when incorporating visual aids, prescriptions and drug packaging review.

West African female sex workers in Mali: reduction in HIV prevalence and differences in risk profiles of sex workers of differing nationalities of origin.

BACKGROUND: Female sex workers (FSW) in Mali are highly vulnerable to HIV. Their prevalence in 2009 was 9 times higher (24.2%) than that among pregnant women (2.7%). METHODS: Four Integrated HIV/sexually transmitted infection (STI) Surveillance and Behavioral Surveys among FSW in Mali (2000, 2003, 2006, and 2009) tracked demographic characteristics, behavior, and HIV and STI prevalence. Logistic regression using generalized estimating equations to control for the cluster effect identified factors associated with HIV-positive serostatus adjusting for potential confounding. RESULTS: Of 2430 FSW, 40.8% were Nigerian, 36.8% were Malian, and 22.4% were from other neighboring countries. Between 2003 and 2009, HIV prevalence dropped from 44.14% to 28.49% (P < 0.0001) among Malians, from 21.33% to 12.71% (P = 0.0082) among Nigerians, and from 43.42% to 33.67% (P = 0.0442) among "others." Between 2000 and 2009, condom availability increased (89.18%-99.3%; P < 0.0001) as did HIV testing (40%-75%; P < 0.0001). Consistent condom use with clients improved for Malians (72.3%-81.5%; P = 0.0092), but not among Nigerians (92.7%-90.94%; P = 0.8240) and "others" (88.9%-88.48%; P = 0.8452). Consistent condom use with boyfriends was low and improved only for Nigerians (9.8%-28.4%; P = 0.0003). Factors associated with HIV prevalence in the multivariate model were older age, study year (2003 and 2006), nationality, lack of education, mobility, STI symptoms, gonorrhea prevalence, and younger age at first sex. CONCLUSIONS: This study documents progress in the fight against HIV among FSW in Mali. The different vulnerabilities to HIV found for different nationality FSW should be considered in programming and future research.