Breaking the clean room barrier: exploring low-cost alternatives for microfluidic devices.

Microfluidics is an interdisciplinary field that encompasses both science and engineering, which aims to design and fabricate devices capable of manipulating extremely low volumes of fluids on a microscale level. The central objective of microfluidics is to provide high precision and accuracy while using minimal reagents and equipment. The benefits of this approach include greater control over experimental conditions, faster analysis, and improved experimental reproducibility. Microfluidic devices, also known as labs-on-a-chip (LOCs), have emerged as potential instruments for optimizing operations and decreasing costs in various of industries, including pharmaceutical, medical, food, and cosmetics. However, the high price of conventional prototypes for LOCs devices, generated in clean room facilities, has increased the demand for inexpensive alternatives. Polymers, paper, and hydrogels are some of the materials that can be utilized to create the inexpensive microfluidic devices covered in this article. In addition, we highlighted different manufacturing techniques, such as soft lithography, laser plotting, and 3D printing, that are suitable for creating LOCs. The selection of materials and fabrication techniques will depend on the specific requirements and applications of each individual LOC. This article aims to provide a comprehensive overview of the numerous alternatives for the development of low-cost LOCs to service industries such as pharmaceuticals, chemicals, food, and biomedicine.

Limited progress in nutrient pollution in the U.S. caused by spatially persistent nutrient sources.

Human agriculture, wastewater, and use of fossil fuels have saturated ecosystems with nitrogen and phosphorus, threatening biodiversity and human water security at a global scale. Despite efforts to reduce nutrient pollution, carbon and nutrient concentrations have increased or remained high in many regions. Here, we applied a new ecohydrological framework to ~12,000 water samples collected by the U.S. Environmental Protection Agency from streams and lakes across the contiguous U.S. to identify spatial and temporal patterns in nutrient concentrations and leverage (an indicator of flux). For the contiguous U.S. and within ecoregions, we quantified trends for sites sampled repeatedly from 2000 to 2019, the persistence of spatial patterns over that period, and the patch size of nutrient sources and sinks. While we observed various temporal trends across ecoregions, the spatial patterns of nutrient and carbon concentrations in streams were persistent across and within ecoregions, potentially because of historical nutrient legacies, consistent nutrient sources, and inherent differences in nutrient removal capacity for various ecosystems. Watersheds showed strong critical source area dynamics in that 2-8% of the land area accounted for 75% of the estimated flux. Variability in nutrient contribution was greatest in catchments smaller than 250 km2 for most parameters. An ensemble of four machine learning models confirmed previously observed relationships between nutrient concentrations and a combination of land use and land cover, demonstrating how human activity and inherent nutrient removal capacity interactively determine nutrient balance. These findings suggest that targeted nutrient interventions in a small portion of the landscape could substantially improve water quality at continental scales. We recommend a dual approach of first prioritizing the reduction of nutrient inputs in catchments that exert disproportionate influence on downstream water chemistry, and second, enhancing nutrient removal capacity by restoring hydrological connectivity both laterally and vertically in stream networks.

Citizen science reveals unexpected solute patterns in semiarid river networks.

Human modification of water and nutrient flows has resulted in widespread degradation of aquatic ecosystems. The resulting global water crisis causes millions of deaths and trillions of USD in economic damages annually. Semiarid regions have been disproportionately affected because of high relative water demand and pollution. Many proven water management strategies are not fully implemented, partially because of a lack of public engagement with freshwater ecosystems. In this context, we organized a large citizen science initiative to quantify nutrient status and cultivate connection in the semiarid watershed of Utah Lake (USA). Working with community members, we collected samples from ~200 locations throughout the 7,640 km2 watershed on a single day in the spring, summer, and fall of 2018. We calculated ecohydrological metrics for nutrients, major ions, and carbon. For most solutes, concentration and leverage (influence on flux) were highest in lowland reaches draining directly to the lake, coincident with urban and agricultural sources. Solute sources were relatively persistent through time for most parameters despite substantial hydrological variation. Carbon, nitrogen, and phosphorus species showed critical source area behavior, with 10-17% of the sites accounting for most of the flux. Unlike temperate watersheds, where spatial variability often decreases with watershed size, longitudinal variability showed an hourglass shape: high variability among headwaters, low variability in mid-order reaches, and high variability in tailwaters. This unexpected pattern was attributable to the distribution of human activity and hydrological complexity associated with return flows, losing river reaches, and diversions in the tailwaters. We conclude that participatory science has great potential to reveal ecohydrological patterns and rehabilitate individual and community relationships with local ecosystems. In this way, such projects represent an opportunity to both understand and improve water quality in diverse socioecological contexts.

Conceptualización de la interacción comunicativa y su caracterización / Conceptualization of communicative interaction and its characterization / Conceptualização de interacção comunicativa e sua caracterização

RESUMEN Este artículo tiene como objetivo definir la interacción comunicativa y cada uno de los elementos que permiten su caracterización. Para esto, se realizó una revisión de la literatura mediante una búsqueda inicial en libros, metabuscadores y diferentes bases de datos, seleccionando la información pertinente según distintas corrientes para la construcción del concepto integrador de la interacción comunicativa y para la descripción de los elementos que permiten su caracterización en dos grandes categorías: las habilidades pragmáticas y las habilidades sociales, teniendo en cuenta las modalidades verbal oral y no verbal desde la perspectiva del modelo sistémico de la comunicación. Se concluye resaltando la importancia que adquieren la interacción comunicativa y sus elementos para el estudio de la comunicación humana, siendo una herramienta útil para que el profesional en fonoaudiología ahonde en su objeto de estudio, actualice sus conocimientos y traslade esta caracterización a los diferentes escenarios en que se desempeña.

ABSTRACT This article aims to define the communicative interaction and each of the elements that allow its characterization. For this, a review of the literature was made through an initial search in books, meta-search engines and different databases, selecting the pertinent information according to different currents for the construction of the integrative concept of the communicative interaction and for the description of the elements that allow its characterization into two broad categories: pragmatic skills and social skills, taking into account verbal and non-verbal modalities from the perspective of the systemic model of communication. It concludes by highlighting the importance of the communicative interaction and its elements for the study of human communication, being a useful tool for the professional in speech and language therapy to focus on their object of study, update their knowledge and transfer this characterization to the different scenarios in that performs.

RESUMO Este artigo visa definir a interação comunicativa e cada um dos elementos que permitem sua caracterização. Para isso, uma revisão da literatura foi feita através de uma busca inicial em livros, meta-motores de busca e diferentes bancos de dados, selecionando a informação pertinente de acordo com diferentes correntes para a construção do conceito integrador da interação comunicativa e para a descrição dos elementos que permitem sua caracterização em duas grandes categorias: habilidades pragmáticas e habilidades sociais, levando em consideração as modalidades verbais e não-verbais da perspectiva do modelo sistêmico de comunicação. Conclui destacando a importância da interação comunicativa e seus elementos para o estudo da comunicação humana, sendo uma ferramenta útil para o profissional na terapia da fala e da linguagem para se concentrar em seu objeto de estudo, atualizar seus conhecimentos e transferir essa caracterização para os diferentes cenários em que executa.