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1.
Adv Mater ; : e2406128, 2024 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-38940075

RESUMEN

The 329-type bismuth (Bi)-based metal halide (MH) polycrystalline films have potential to be applied in the new generation of X-ray imaging technology owing to high X-ray absorption coefficients and excellent detection properties. However, the mutually independent [Bi2X9]3- units and numerous grain boundaries in the material lead to low carrier transport and collection capabilities, severe ion migration, large dark currents, and poor response uniformity. Here, a new multi-phenyl ring methyltriphenylphosphonium (MTP) is designed to optimize the energy band structure. For the first time, the coupling between the A-site cation and [Bi2X9]3- is realized, making it the main contributor to the conduction band minimum (CBM), getting rid of dilemma that carrier transport is confined to [Bi2X9]3-. Further, the preparation of MTP3Bi2I9 amorphous large-area wafer is achieved by melt-quenching; the steric hindrance effect improves stability, increases ion migration energy, and promotes response uniformity (14%). Moreover, the amorphous structure takes advantage of A-site cation participation in the conductivity, achieving a record sensitivity (7601 µC Gy-1 cm-2) and low dark current (≈0.11 nA) in the field of amorphous X-ray detection, and features low-temperature large-area preparation. Ultimately, designing amorphous array imaging devices that exhibit excellent response uniformity and potential imaging capabilities is succeeded here.

2.
J Appl Physiol (1985) ; 136(6): 1478-1487, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38695357

RESUMEN

Our aim was to develop and validate separate whole body sweat rate prediction equations for moderate to high-intensity outdoor cycling and running, using simple measured or estimated activity and environmental inputs. Across two collection sites in Australia, 182 outdoor running trials and 158 outdoor cycling trials were completed at a wet-bulb globe temperature ranging from ∼15°C to ∼29°C, with ∼60-min whole body sweat rates measured in each trial. Data were randomly separated into model development (running: 120; cycling: 100 trials) and validation groups (running: 62; cycling: 58 trials), enabling proprietary prediction models to be developed and then validated. Running and cycling models were also developed and tested when locally measured environmental conditions were substituted with participants' subjective ratings for black globe temperature, wind speed, and humidity. The mean absolute error for predicted sweating rate was 0.03 and 0.02 L·h-1 for running and cycling models, respectively. The 95% confidence intervals for running (+0.44 and -0.38 L·h-1) and cycling (+0.45 and -0.42 L·h-1) were within acceptable limits for an equivalent change in total body mass over 3 h of ±2%. The individual variance in observed sweating described by the predictive models was 77% and 60% for running and cycling, respectively. Substituting measured environmental variables with subjective assessments of climatic characteristics reduced the variation in observed sweating described by the running model by up to ∼25%, but only by ∼2% for the cycling model. These prediction models are publicly accessible (https://sweatratecalculator.com) and can guide individualized hydration management in advance of outdoor running and cycling.NEW & NOTEWORTHY We report the development and validation of new proprietary whole body sweat rate prediction models for outdoor running and outdoor cycling using simple activity and environmental inputs. Separate sweat rate models were also developed and tested for situations where all four environmental parameters are not available, and some must be subsequently estimated by the user via a simple rating scale. All models are freely accessible through an online calculator: https://sweatratecalculator.com. These models, via the online calculator, will enable individualized hydration management for training or recreational cycling or running in an outdoor environment.


Asunto(s)
Ciclismo , Carrera , Sudoración , Humanos , Carrera/fisiología , Sudoración/fisiología , Masculino , Ciclismo/fisiología , Adulto , Femenino , Ejercicio Físico/fisiología , Adulto Joven , Temperatura , Modelos Biológicos , Australia
3.
Bioresour Technol ; 102(16): 7486-93, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21624827

RESUMEN

Compounds inhibitory to enzymatic hydrolysis and fermentation are generated from neutral steam exploded corn stover in the process of producing bio-ethanol. In this study, weak acids were identified as main yeast inhibitors, while phenols and aldehyde contribute to the inhibition to a lower degree. Main weak acids in hydrolysates are acetic acid and formic acid, for which critical levels for yeast inhibition are 6 and 4g/L, respectively. The inhibitory effect of these compounds can be greatly overcome by increasing pH of hydrolysates to 6.0-9.0, but there is a risk of bacterial contamination when fermenting at high pH. The relationship of pH, total solids of hydrolysates, fermentation and contamination was studied in detail. Results indicate that the contamination by bacteria when fermenting at high pH can be prevented effectively using hydrolysates with total solids of more than 20%. Meanwhile, ethanol yield is improved significantly.


Asunto(s)
Biocombustibles , Etanol/metabolismo , Lignina/química , Saccharomyces cerevisiae/metabolismo , Ácido Acético/química , Bacterias/crecimiento & desarrollo , Biomasa , Etanol/química , Fermentación , Formiatos/química , Furaldehído/análogos & derivados , Furaldehído/química , Concentración de Iones de Hidrógeno , Fenoles/química , Saccharomyces cerevisiae/enzimología , Zea mays/química
4.
Appl Biochem Biotechnol ; 137-140(1-12): 221-38, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18478391

RESUMEN

Ensilage can be used to store lignocellulosic biomass before industrial bioprocessing. This study investigated the impacts of seven commercial enzyme mixtures derived from Aspergillus niger, Trichoderma reesei, and T. longibrachiatum. Treatments included three size grades of corn stover, two enzyme levels (1.67 and 5 IU/g dry matter based on hemicellulase), and various ratios of cellulase to hemicellulase (C:H). The highest C:H ratio tested, 2.38, derived from T. reesei, resulted in the most effective fermentation, with lactic acid as the dominant product. Enzymatic activity during storage may complement industrial pretreatment; creating synergies that could reduce total bioconversion costs.


Asunto(s)
Proteínas Bacterianas/química , Glicósido Hidrolasas/química , Residuos Industriales/prevención & control , Ácido Láctico/química , Ensilaje/microbiología , Zea mays/química , Activación Enzimática
5.
Biotechnol Prog ; 22(1): 78-85, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16454495

RESUMEN

Ensilage is a truncated solid-state fermentation in which anaerobically produced organic acids accumulate to reduce pH and limit microbial activity. Ensilage can be used to both preserve and pretreat biomass feedstock for further downstream conversion into chemicals, fuels, and/or fiber products. This study examined the ensilage of enzyme-treated corn stover as a feedstock for particleboard manufacturing. Corn stover at three different particle size ranges (<100, <10, and <5 mm) was ensiled with and without a commercial enzyme mixture having a cellulase:hemicellulase ratio of 2.54:1, applied at a hemicellulase rate of 1670 IU/kg dry mass. Triplicate 20 L mini-silos were destructively sampled and analyzed on days 0, 1, 7, 21, 63, and 189. Analysis included produced organic acids and water-soluble carbohydrates, fiber fractions, pH, and microorganisms, including Lactobacillus spp. and clostridia were monitored. On days 0, 21, and 189, the triplicate samples were mixed evenly and assembled into particleboard using 10% ISU 2 resin, a soy-based adhesive. Particleboard panels were subjected to industry standard tests for modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding strength (IB), thickness swell (TS), and water absorption at 2 h boiling and 24 h soaking. Enzyme addition did improve the ensilage process, as indicated by sustained lower pH (P < 0.0001), higher water-soluble carbohydrates (P < 0.05), and increased lactic acid production (P < 0.0001). The middle particle size range (<10 mm) demonstrated the most promising results during the ensilage process. Compared with fresh stover, the ensilage process did increase IB of stover particleboard by 33% (P < 0.05) and decrease water adsorption at 2 h boiling and 24 h soaking significantly (P < 0.05). Particleboard panels produced from substrate ensiled with enzymes showed a significant reduction in water adsorption of 12% at 2 h boiling testing. On the basis of these results, ensilage can be used as a long-term feedstock preservation method for particleboard production from corn stover. Enzyme-amended ensilage not only improved stover preservation but also enhanced the properties of particleboard products.


Asunto(s)
Biotecnología , Materiales Manufacturados , Madera , Zea mays/microbiología , Bacterias/enzimología , Celulosa/metabolismo , Clostridium/enzimología , Clostridium/metabolismo , Concentración de Iones de Hidrógeno , Lactobacillus/enzimología , Lactobacillus/metabolismo , Tamaño de la Partícula , Solubilidad , Estrés Mecánico
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