Ionic Conductive Cellulose Mats by Solution Blow Spinning as Substrate and a Dielectric Interstrate Layer for Flexible Electronics.

Renewable cellulose substrates with submicron- and nanoscale structures have revived interest in paper electronics. However, the processes behind their production are still complex and time- and energy-consuming. Besides, the weak electrolytic properties of cellulose with submicron- and nanoscale structures have hindered its application in transistors and integrated circuits with low-voltage operation. Here, we report a simple, low-cost approach to produce flexible ionic conductive cellulose mats using solution blow spinning, which are used both as dielectric interstrate and substrate in low-voltage devices. The electrochemical properties of the cellulose mats are tuned through infiltration with alkali hydroxides (LiOH, NaOH, or KOH), enabling their application as dielectric and substrate in flexible, low-voltage, oxide-based field-effect transistors and pencil-drawn resistor-loaded inverters. The transistors exhibit good transistor performances under operation voltage below 2.5 V, and their electrical performance is strictly related to the type of alkali ionic specie incorporated. Devices fabricated on K+-infiltrated cellulose mats present the best characteristics, indicating pure capacitive charging of the semiconductor. The pencil-drawn load resistor inverter presents good dynamic performance. These findings may pave the way for a new generation of low-power, wearable electronics, enabling concepts such as the "Internet of Things".

Halochromic Polystyrene Nanofibers Obtained by Solution Blow Spinning for Wine pH Sensing.

Colorimetric sensors developed by the solution blow spinning (SBS) technique have a rapid response to a variation in different physicochemical properties. In this study, polystyrene nanofibrous (PSNF) mats containing the bromothymol blue (BTB) indicator were obtained by SBS for the pH sensing of wine sample. The incorporation of the indicator did not promote changes in fiber diameter but led to the appearance of beads, allowing for the encapsulation of BTB. The halochromic property of BTB was retained in the PSNF material, and the migration tests showed that the indicator mats presented values below the maximum acceptable limit (10 mg dm-2) established by EU Commission Regulation No. 10/2011 for foods with an alcohol content up to 20%. The present study opens the possibility of applying nanostructured materials to innovative food packaging which, through nanosensory zones, change color as a function of the food pH.

Avaliação das condições higiênicas e físico-estruturais do centro de abastecimento de pescados em uma cidade do nordeste brasileiro / Evaluation of the hygienic and physical-structural conditions of the fish supply center in a city in northeastern Brazil

Fish are perishable, requiring adequate sanitary conditions since their capture, manipulation and commercialization. Therefore, the objective was to evaluate the hygienic conditions and physical structure of the Fish Supply Center. It was a cross-sectional study. Hygienic conditions and physical structure were evaluated by means of a checklist elaborated according to RDC nº 216/2004. Regarding the results, a total of 84% non-conformity was obtained. Thus, all the aspects investigated showed close percentages and above 70% of nonconformity in all parameters evaluated. Therefore, it is essential to ensure the quality of the fish and the adequacy to the current legislation the use of good food handling practices. In order to avoid such products from becoming a source of foodborne diseases. It is also worth noting the need for concrete actions of public health coming from the local municipal public power to improve the physical conditions of the establishment.