Attempts to polymerize trinitrobenzene derivatives (TNB) have been fruitless so far. Accordingly, polymers containing TNB have not been exploited in spite of their envisaged potential applications. ...Here, we describe two ways for preparing polymers with TNB moieties thus overcoming the previously reported polymerization impairments. We also report on the exploitation of the materials, both obtained as tractable transparent films and coated fibers, as smart labels for the visual detection of amine vapors. More precisely, amines in the atmosphere surrounding the sensory materials diffuse into them reacting with the TNB motifs forming highly colored Meisenheimer complexes, giving rise to development of color and to the naked eye sensing phenomenon. This is the case of highly volatile amines, such as trimethylamine, produced in food spoilage, specifically in the deterioration of fish or meat, for which the color development of the smart labels can be used as a visual test for food freshness.
Is this fish fresh? Polymers containing chemically anchored trinitrobenzene motifs are exploited as colorimetric sensors for biogenic amine vapors. Tractable transparent films and coated fibers as chromogenic smart labels are reported. Therefore, the color change of these materials upon interaction/detection of volatile amines produced in food spoilage, specifically in the deterioration of fish or meat, can be used as a visual test for food freshness.
This paper presents the implementation of an AC three-phase programmable electronic load (PEL) that emulates load profiles and can be used for testing equipment in microgrids (MGs). The implemented ...PEL topology is built with a voltage source inverter (VSI) which works as a current controlled source and a Buck converter which permits the dissipation of active power excess. The PEL operation modes according to the interchange of active and reactive power and its operation in four quadrants were determined. The power and current limits which establish the control limitations were also obtained. Three control loops were implemented to independently regulate active and reactive power and ensure energy balance in the system. The main contribution of this paper is the presentation a detailed analysis regarding hardware limitations and the operation of the VSI and Buck converter working together. The PEL was implemented for a power of 1.8 kVA. Several experimental results were carried out with inductive, capacitive, and resistive scenarios to validate the proper operation of the PEL. Experimental tests showed the correct behavior of the AC three-phase currents, VSI input voltage, and Buck converter output voltage of the PEL for profile changes, including transient response.
La distribución geoespacial de la morbilidad por tuberculosis (TB) pulmonar y extrapulmonar en el municipio de Cúcuta en los años 2019 y 2020 se describió utilizando el método de Kulldorff usando la ...ubicación geográfica y la fecha de reporte de los casos incidentes de TB. La unidad de análisis fue el evento reportado al Sistema Nacional de Vigilancia Epidemiológica (SIVIGILA). Se identificaron 392 barrios distribuidos en diez comunas, donde se ubicaron 607 casos. En la distribución de la TB pulmonar, la comuna norte fue la que más casos reportó, siendo el barrio El Salado el más afectado de manera repetitiva. Los casos incidentes de TB extrapulmonar no mostraron patrones de repetición en la distribución entre las unidades espaciales y temporales. Se debe priorizar la región occidental dentro de las estrategias de mitigación y control de la propagación de la infección pulmonar del territorio.
The introduction of host units, also called binding sites or receptor subunits, and fluorescence or chromogenic signaling motifs into the lateral or into the main polymer chain opens the way for ...cutting-edge applications related to the selective interaction of these chemical sites with guest or target molecules (i.e., cations, anions or neutral molecules). Thus, the good mechanical properties of these polymers permit the design and preparation of "á la carte" fluorogenic or colorimetric probes for sensing diverse analytes. These polymeric probes may work in organic or aqueous solutions and, most importantly, in the solid state, as finished materials, can operate in aqueous media, permitting the preparation of "naked-eye" solid probes to be used by non-specialist personnel, for example, to control the concentration of analytes in chemical industries or to test whether environmental polluting chemicals exceed the legal limits.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
El presente documento tiene como objetivo evaluar el enfoque de género en la enseñanza de la geografía en los programas de Licenciatura en Ciencias Sociales y del pregrado en Geografía de cuatro ...universidades públicas de Colombia: Pedagógica Nacional, Pedagógica y Tecnológica de Colombia, del Atlántico y del Valle. Se empleó una metodología cualitativa que contempló la revisión de literatura, los contenidos curriculares y la producción de trabajos de grado en las cuatro universidades de estudio. Los resultados muestran la poca incidencia del enfoque de género en la enseñanza de la geografía en la Educación Superior, en tanto contenidos, literatura de reflexión y como investigación. También, que emerge lentamente el enfoque de género en los trabajos de grado, aunque no son abordados directamente desde la geografía.
This paper describes the preparation of a hydrophilic copolymer membrane with two comonomers: 1-vinyl-2-pyrrolidone (commercial) and a new water insoluble piperazinedione derivative, which is a ...fluorogenic mercury sensing motif. The dense membrane permitted the fluorogenic detection of Hg²⁺ in aqueous media. The sensitivity of the membrane this cation was significantly high, with a detection limit of 10ppt. This limit of detection is much lower than that of DMSO/water solutions of the sensing monomer, which is 10ppb, and significantly lower than the maximum contaminant level (EPA) in drinking water, 2ppb.
The preparation of a fluorogenic sensory material for the detection of biomolecules is described. Strategic functionalisation and copolymerisation of a water insoluble organic sensory molecule with ...hydrophilic comonomers yielded a crosslinked, water-swellable, easy-to-manipulate solid system for water "dip-in" fluorogenic coenzyme A, cysteine, and glutathione detection by means of host-guest interactions. The sensory material was a membrane with gel-like behaviour, which exhibits a change in fluorescence behaviour upon swelling with a water solution of the target molecules. The membrane follows a "turn-on" pattern, which permits the titration of the abovementioned biomolecules. In this way, the water insoluble sensing motif can be exploited in aqueous media. The sensory motif within the membrane is a chemically anchored piperazinedione-derivative with a weakly bound Hg(II). The response is caused by the displacement of the cation from the membrane due to a stronger complexation with the biomolecules, thus releasing the fluorescent sensory moieties within the membrane.
Bronchotomy for metal foreign object removal in pediatric airway Marín Giraldo, Andres Felipe; Bustillos Serna, Carlos Felipe; Figueroa Gutiérrez, Luis Mauricio ...
Journal of pediatric surgery case reports,
February 2023, 2023-02-00, 2023-02-01, Letnik:
89
Journal Article
Recenzirano
Odprti dostop
Foreign Body Aspiration (FBA) is a common medical emergency in children, demands a prompt diagnosis through clinical manifestations and radiological studies, to prevent complications and mortality. ...We present a case of a one-year-old female patient that accidently aspirated a foreign metal object into her airway. Two unsuccessful extractions through bronchoscopies were attempted, therefore a bronchotomy was carried out to remove the foreign object. The patient was uneventfully discharged after being monitored and receiving systemic antibiotics in the general hospitalization ward for seven days.
Introducción. La evaluación de la movilidad de las cuerdas vocales en cirugía de tiroides y paratiroides hace parte de la adecuada valoración integral. Aunque la laringoscopia directa es prueba de ...referencia, su uso real no es rutinario por lo que se propone la ecografía translaríngea como alternativa de evaluación.
Métodos. Estudio prospectivo de evaluación de una prueba diagnóstica de la movilidad de las cuerdas vocales pre y posoperatoria, comparando la ecografía translaríngea con la video laringoscopia, en pacientes con cirugía de tiroides y paratiroides, de febrero 1° a noviembre 30 de 2022. Se describieron las variables usando frecuencias absolutas y relativas. En el análisis univariado se calcularon Chi cuadrado y T de Student y en el bivariado, regresión logística binaria. La agudeza diagnóstica se determinó con sensibilidad, especificidad y valores predictivos; se consideró la significancia estadística con p < 0,05.
Resultados. Se incluyeron 267 pacientes, 219 mujeres y 48 hombres; 196 pacientes (73,4%) tenían malignidad. Se encontró en el preoperatorio, sensibilidad 100 %, especificidad 99,6 %, VPP 83,3 %, VPN 100 %, odds de probabilidad positiva 83 % y Odds de probabilidad negativa 0,004 %. En el posoperatorio, sensibilidad 82,8 %, especificidad 99,2 %, VPP 92,3 % VPN 97,9 %, odds de probabilidad positiva 92 % y odds de probabilidad negativa 0,2 %.
Conclusiones. La ecografía translaríngea en nuestro medio tiene alta agudeza diagnóstica. Podría ser usada en el abordaje inicial de la evaluación de la movilidad de las cuerdas vocales y reemplazar la laringoscopia directa, dejando ésta para cuando la visualización ecográfica no sea adecuada, o en casos de afectación o sospecha de invasión, para su confirmación.
This paper proposes a Python tool for the analysis of balanced, unbalanced, sinusoidal and nonsinusoidal three-phase systems based on the IEEE Std. 1459. The proposed tool was developed to be used by ...electrical engineers and professionals of related careers providing a free access for electrical power calculations that allows validation and power analysis in power systems. The proposed tool is available for use on a GitHub link and only requires voltage and current signals as inputs, making it possible to dispense expensive commercial network analyzers. The tool is made of two interfaces, one for making power calculations of sinusoidal three-phase systems and the other one for making calculations of nonsinusoidal three-phase systems; both interfaces can be accessed through a main menu. The proposed tool facilitates decision-making in electrical system issues, which helps improving the efficiency and power quality of electrical systems.
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