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Background: Device manufacturers who seek to market their pediatric facemasks in the United States (U.S.), as part of anthropometric data requirement, need to demonstrate their mask designs are expected to fit the intended user population. However, currently there are no well accepted test methodologies for pediatric facemasks. In addition, unlike N95 respirators, the expected maximum flow rate, and the pressure drop at that expected maximum flow rate for pediatric facemasks have not been established. Method: The objective of this article is three-fold; use a literature survey to determine the worst-case flow rate, and an acceptable breathing resistance; and come up with a bench-test based protocol for assessing fit of pediatric facemasks. Results & discussion: The worst-case breathing flow rate for mask testing in the pediatric population is 45–60 Liters/minute (LPM), and the acceptable pressure drop at the worst-case flow rate is 2.0 mmH2O. A retrospective assessment of all the four brands of legally marketed facemasks in the U.S. that could be purchased, revealed that majority of the brands have high filtration efficiency (>95%) at low flow rate 5 LPM which reduces to ~ 80% at 45 LPM. At 5 LPM, the pressure drop ranges from 0.3–0.6 mmH2O, remaining below the 2.0 mmH2O. However, at higher flow rates, (representing strenuous activities, or older children (> 12 years)), most masks exhibited a pressure drop within the range of 2.9 to 6.0 mmH2O. Furthermore, opening the pleats of the facemasks completely results in a notable reduction in pressure drop (a 6.6-fold decrease, p = 0.03). To assess fit of these same brands of facemasks, we then updated our previous validated adult manikin fit-test method and used it in manikins in the age group of 2 to 14 years. Either poor nose-clip adherence to the manikin, low filtration efficiency of the pediatric facemasks, or off-label use (i.e. when donned on manikins representing 2 years to 14 years) contributed to low fit. Conclusions: A new bench-top tool to evaluate quantitative fit of pediatric facemasks was developed. In addition, based on the research reported here, we provide practical implications for the members of the community: users, academia and medical device manufacturers. [ABSTRACT FROM AUTHOR]

A novel adsorbent prepared by the immobilization of 2,4-dinitrophenylhydrazine (DNPH) on TiO2 nanoparticles has been investigated for the removal of formaldehyde from aqueous solutions. Sodium dodecyl sulfate (SDS) surfactant was used to improve the DNPH grafting to the TiO2 surface. Isotherm modeling revealed that the Langmuir equation could better describe the adsorption of formaldehyde onto the TiO2/SDS/DNPH and the maximum adsorption capacity obtained was 51.282 mg/g. The equilibrium parameter (RL) indicated that TiO2/SDS/DNPH nanocomposites are useful for the removal of formaldehyde from aqueous solutions. Kinetic studies showed the best applicability of the pseudo-first-order model. It was found that the adsorption rate is rapid at the initial stages and reaches equilibrium after 245 min. According to the adsorption thermodynamics, ΔH°, ΔG°, and ΔS° were calculated as –26.1, –5.6, and –63.2 (kJ/mol), respectively. Negative values obtained for thermodynamic parameters show that the reaction is exothermic and spontaneous at room temperature. Adsorption–desorption studies indicated that the prepared adsorbent kept its adsorption efficiencies constant over 5 cycles. The best conditions for TiO2/SDS/DNPH nanocomposites to remove 96.2% formaldehyde were an adsorbent dosage of 1.1 g/L, a pH of 7.424 and a contact time of 183.290 min. [ABSTRACT FROM AUTHOR]

In this paper, a comprehensive model is proposed to design a network for a multi-period, multi-echelon and multi-product inventory controlled supply chain. Various marketing strategies and guerrilla marketing approaches are considered in the design process under the static competition condition. The goal of the proposed model is to efficiently respond to the customer's demands in the presence of the pre-existing competitors and the price inelasticity of demands. The proposed optimization model considers multiple objectives that incorporate both market share and total profit of the considered supply chain network, simultaneously. To tackle the proposed multi-objective mixed-integer nonlinear programming model, an efficient hybrid meta-heuristic algorithm is developed that incorporates a Taguchi-based non-dominated sorting genetic algorithm-II and a particle swarm optimization. A variable neighborhood decomposition search is applied to enhance a local search process of the proposed hybrid solution algorithm. Computational results illustrate that the proposed model and solution algorithm are notably efficient in dealing with the competitive pressure by adopting the proper marketing strategies. [ABSTRACT FROM AUTHOR]

Objective: The present investigation aims to evaluate the prevalence of IgM and IgG anti-7, gondii antibodies and the associated risk factors among healthy blood donors in Mashhad city, Razavi Khorasan province, Iran. Methods: We screened a total of 500 serum samples by census method from apparently healthy blood donors of the Mashhad Blood Transfusion Organization (MBTO) for IgG and IgM anti-T gondii antibodies by enzyme linked immunosorbent assay (ELISA). Results: We found that 29.6%, 25%, 1.4%, and 3.2% of tested donors were positive for anti-T gondii antibodies, only IgG antibody, both IgM and IgG, and IgM antibody alone, respectively. Several risk factors which were significantly related to T gondii seropositivity in the univariate analysis at P < 0.05 included female gender (OR = 3.222, P < 0.001), age more than 40 years (P = 0.026), and sausage/hot dog consumption (OR = 4.472, P < 0.001). Conclusions: The results of this study can be a warning for blood transfusion organizations to pay special attention to toxoplasmosis among blood donors and also design screening programs for prevention of transfusion-transmitted toxoplasmosis. sis [ABSTRACT FROM AUTHOR]