Débora Gonçalves

Providing employees with proper work conditions should be one of the main concerns of any employer. Even so, in many cases, work shifts chronically expose the workers to a wide range of potentially harmful compounds, such as ammonia. Ammonia has been present in the composition of products commonly used in a wide range of industries, namely production in lines, and also laboratories, schools, hospitals, and others. Chronic exposure to ammonia can yield several diseases, such as irritation and pruritus, as well as inflammation of ocular, cutaneous, and respiratory tissues. In more extreme cases, exposure to ammonia is also related to dyspnea, progressive cyanosis, and pulmonary edema. As such, the use of ammonia needs to be properly regulated and monitored to ensure safer work environments. The Occupational Safety and Health Administration and the European Agency for Safety and Health at Work have already commissioned regulations on the acceptable limits of exposure to ammonia. Nevertheless, the monitoring of ammonia gas is still not normalized because appropriate sensors can be difficult to find as commercially available products. To help promote promising methods of developing ammonia sensors, this work will compile and compare the results published so far.

En este artículo de revisión se discuten los principales procesos de deterioro y del uso de preservadores naturales de la madera, en particular en Brasil, teniendo en cuenta su relevancia en Latinoamérica. Pretende también ser una contribución a los trabajos que tratan de los avances y del desarrollo de nuevas composiciones para preservar maderas. Se contextualiza la problemática de la protección y degradación química de la madera, temas de interés en la actualidad, tanto en Brasil como en otros países. Además, se discute el uso de nuevos productos, tales como aceites de neem y de ricino, extractos de pimientos, taninos, tall oil, aceite vegetal de linaza, aceites esenciales extraídos de maderas nativas y quitosano, y sobre la problemática del bajo uso comercial de productos naturales. En términos de soluciones, hay la necesidad de más estudios de campo y de modificar las formulaciones con agentes de fijación, biocidas, antioxidantes, y aditivos. También hay que tener en cuenta los aspectos legales de la comercialización de nuevas formulaciones en países ricos en recursos naturales pero subdesarrollados.

Electrochemical immunosensors have been developed to determine the carbohydrate antigen 19-9 (CA19-9). They are based on screen-printed carbon electrodes (SPCEs) coated with layer-by-layer (LbL) films of carbon black (CB) and polyelectrolytes. Owing to a suitable choice of LbL film architecture, the procedures for immobilization of anti-CA19-9 antibodies on the electrode surfaces were straightforward. Mechanically flexible immunosensors were capable of detecting CA19-9 within a dynamic range of 0.01 to 40 U mL⁻¹ and a limit of detection of 0.07 U mL⁻¹ using differential pulse voltammetry. In addition to detecting CA19-9 at clinically relevant concentrations for pancreatic cancer in standard solutions, the immunosensors provide the determination of CA19-9 on cell lysate and human serum samples. Using LbL films led to immunosensors with superior performance compared to similar systems obtained by drop casting. The fabrication of this relatively simple, inexpensive platform is a demonstration that SPCEs modified with cost-effective materials are able to detect cancer biomarkers and may be adapted to other disposable immunosensors. Schematic representation of assembly and characterization of electrochemical immunosensors for the determination of carbohydrate antigen 19-9 based on printed electrodes modified with composites of carbon black and polyelectrolyte films