Graphene Nanoplatelet Exoskeleton on Polyurethane Foam to Produce Flame‐Retardant, Piezoresistive, and Electromagnetic Interference Shielding Surfaces

Abstract Polyurethane foam (PUF)’s porous structure, light weight, flexibility, and low‐cost properties make it useful in various cutting‐edge technologies. However, time‐consuming, costly, and complicated surface modification methods severely hinder its commercial applications. Herein, an ultrafast, simple, and cost‐effective surface modification method based on the evaporation of a low boiling point solvent to prepare a multifunctional graphene nanoplatelet (GNP)‐decorated PUF (GNP@PUF) is proposed. Due to the passive heat barrier of GNP sheets, the resulting sponge exhibits excellent flame retardancy by reducing the critical fire retardancy metrics, that is, peak heat release rate, total heat release, and total smoke release by 72%, 50%, and 81%, respectively. In addition, GNP@PUF can function as a piezoresistive sensor and electromagnetic interference (EMI)‐shielding material. As a piezoresistive sensor, it exhibits a wide‐compressive pressure (2.4–112 kPa)/strain (5–70%) range and ultra‐fast response/relaxation time (48/35 ms), wide‐stretching strain (5–100%) range, and it can detect minute human motions by being attached to different parts of the human body. Meanwhile, the composite foam displays good absorption‐dominant EMI shielding performance (≈38 dB), possibly due to conductive dissipation and multiple reflections/scattering of EM waves inside the 3D conductive graphene network. This study provides a simple coating technique for developing multifunctional lightweight foam materials

Blinded rechecking of sputum smear microscopy performance in public health facilities in Tigray region, Northern Ethiopia: Retrospective cross sectional study.

IntroductionTuberculosis disease is the leading cause of death worldwide along with HIV/AIDS. Sputum smear microscopy plays an essential role for initial TB diagnosis and treatment follow up. But, misdiagnosis of sputum smear microscopy revealed a high economical crisis and missing of active TB cases. This study was aimed to determine blinded rechecking of sputum smear microscopy performance in public health facilities in Tigray region, Northern Ethiopia.Materials and methodsA cross sectional retrospective study was conducted from January, 2017 to December, 2018 year. Data was collected retrospectively using electronic and paper based in Tigray health research institute. The data was analyzed using the SPSS version 25 software. The sensitivity, specificity, positive predictive value, and negative predictive value of the smear readings were calculated using 2X2 contingency table. The reading agreement between the microscopic center and reference center was determined using kappa statistics.ResultsA total of 23,456 blinded rechecked smear results were reviewed. In average, the performances of sputum smear quality were 61%, 68%, 64%, 66%, 62% and 75% for specimen quality, staining quality, smear size, smear thickness, smear evenness and smear cleanliness respectively. Of the total error (0.48%) reported, 0.25%, 0.19% and 0.085% were false positive, false negative and quantification errors respectively. The concordance rate of health facilities for smear reading was increased to 90% by the end of 2018. Overall, the sensitivity, specificity, PPV, and NPV of the smear readings were 95%, 99.7%, 93% and 99.8% respectively. Likewise, the smear reading agreement was also perfect with kappa value, 0.87.ConclusionThe overall performance of public health facilities for blinded rechecking of smear microscopy was satisfactory. But, the high false positive and false negative errors found calls for continuous evaluation and monitoring of the health facilities by reference center

Novel and emerging prebiotics: Advances and opportunities

Consumers are conscientiously changing their eating preferences toward healthier options, such as functional foods enriched with pre- and probiotics. Prebiotics are attractive bioactive compounds with multidimensional beneficial action on both human and animal health, namely on the gastrointestinal tract, cardiometabolism, bones or mental health. Conventionally, prebiotics are non-digestible carbohydrates which generally present favorable organoleptic properties, temperature and acidic stability, and are considered interesting food ingredients. However, according to the current definition of prebiotics, application categories other than food are accepted, as well as non-carbohydrate substrates and bioactivity at extra-intestinal sites. Regulatory issues are considered a major concern for prebiotics since a clear understanding and application of these compounds among the consumers, regulators, scientists, suppliers or manufacturers, health-care providers and standards or recommendation-setting organizations are of utmost importance. Prebiotics can be divided in several categories according to their development and regulatory status. Inulin, galactooligosaccharides, fructooligosaccharides and lactulose are generally classified as well established prebiotics. Xylooligosaccharides, isomaltooligosaccharides, chitooligosaccharides and lactosucrose are classified as “emerging” prebiotics, while raffinose, neoagaro-oligosaccharides and epilactose are “under development.” Other substances, such as human milk oligosaccharides, polyphenols, polyunsaturated fatty acids, proteins, protein hydrolysates and peptides are considered “new candidates.” This chapter will encompass actual information about the non-established prebiotics, mainly their physicochemical properties, market, legislation, biological activity and possible applications. Generally, there is a lack of clear demonstrations about the effective health benefits associated with all the non-established prebiotics. Overcoming this limitation willThe authors acknowledge the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte; and the projects COMPETE 2020 (POCI-01-0145-FEDER-006684), FoSynBio (POCI-01-0145-FEDER 029549) and NewFood (NORTE-01-0246-FEDER-000043). CA and BBC acknowledge their grants (UMINHO/BPD/4/2019 and SFRH/BD/132324/2017) from FCT