Photoacoustic detection of ammonia exhaled by individuals with chronic kidney disease.

Ammonia (NH3) has been reported as a breath biomarker for chronic kidney disease (CKD) usually detected at concentrations greater than 0.25 parts per million by volume (ppmV). NH3 was detected in breath of individuals with CKD through gaseous photoacoustic spectroscopy (PAS). The efficiency of hemodialysis (HD) was demonstrated. Eight volunteers aged between 20 and 60 years and without previous respiratory disease were eligible, among which six were control volunteers (CV) and two volunteers with advanced CKD, named CKDV1 and CKDV2. The presence of CKD was confirmed by the calculation of creatinine clearance (CC) according to the Cockcroft-Gault equation. Before HD, the mean NH3 concentration exhaled by CKDV1 was 0.9 ± 0.1 ppmV and after HD was 0.20 ± 0.03 ppmV, which demonstrated an efficiency of 76% NH3 reduction in breath. The CKDV2 exhaled 1.27 ± 0.03 ppmV of NH3 pre-HD and 0.42 ± 0.08 ppmV post-HD, which resulted in efficiency of about 67%. It was not possible to quantify NH3 from CV, what led us to infer that all of them exhaled amounts below the detection limit, i.e., 0.20 ppmV. This assumption is underpinned by CC, whose values hovered at 90 ≤ CC ≤ 120 mL/ min, confirming normal renal function.

Monitoring of ammonia concentrations from coir-husk litter of Brazilian poultry house using diode laser photoacoustic spectroscopy.

Ammonia (NH[Formula: see text]) from manure is a concern in raising broiler due to possible damages to production and the environment. Brazil is the main exporter of chicken meat in the world and is also responsible for large waste of poultry litter. The country, likewise, figures as top 5 producers of green coconut, which results in considerable volumes of waste, since 80%-85% of the fruit is unusable. This work analyzes the ammonia concentration profile of two bedding substrates for raising broiler, to know, coir-husk fiber and a commonly used pine wood shavings in a Brazilian climate. A differential home-made photoacoustic cell combined with a diode laser was employed for sensing ammonia at trace levels. Such combination confers selectivity as well as lower limits of detection to the system. The chemical compositions pH, N, C, Ca, Mg, P[Formula: see text]O[Formula: see text] and K[Formula: see text]O were also determined, in addition to the moisture, dry matter and mineral content of substrates and litters. NH[Formula: see text] concentrations varied from (0.9 ± 0.3) ppmv to (19 ± 3) ppmv and from (2.1 ± 0.5) ppmv to (21 ± 3) ppmv for the coir-husk fiber and wood shavings substrates, respectively. Results showed the feasibility of using coconut fiber as poultry litter in regions where this material is a common waste. Moreover, as NH[Formula: see text] concentrations were lower for coconut fiber bedding compared to shavings, this coir-husk fiber is a potential residue to guarantee the environmental sustainability by Brazilian poultry farming. Coir-husk fibers presented significantly higher amounts of P and K in comparison to pine wood. NH[Formula: see text] profiles revealed that coir-husk fiber emitted lower quantities than wood shavings. Besides, a delay on the NH[Formula: see text] emission pattern was clearly seen when the coconut waste was the bedding material. Such a tendency was confirmed by the logistic model. Our findings, in turn, make the coir-husk an environmentally friendly alternative low-cost product for poultry litter as well as its potential use as natural fertilizer. The later deserves attention since there is a need to accurately assess the emissions of methane, nitrous oxide, and carbon dioxide during the composting process. In Brazil, the waste generated by the high production of green coconut is an environmental liability. The cost of poultry production has been high, reducing the profit of producers, who seek to make production cheaper. Measuring NH[Formula: see text] from poultry activity in Brazil, a tropical country, aims to control management and reduce production losses, since NH[Formula: see text] is a harmful gas to birds. The measurement of NH[Formula: see text] concentrations at trace levels from raising broilers by photoacoustic diode laser spectroscopy, to the best of our knowledge, has been reported for the very first time.

Mitochondrial dysfunction associated with ascorbate synthesis in plants.

Mitochondria are the major organelles of energy production; however, active mitochondria can decline their energetic role and show a dysfunctional status. Mitochondrial dysfunction was induced by high non-physiological level of L-galactone-1,4-lactone (L-GalL), the precursor of ascorbate (AsA), in plant mitochondria. The dysfunction induced by L-GalL was associated with the fault in the mitochondrial electron partition and reactive oxygen species (ROS) over-production. Using mitochondria from RNAi-plant lines harbouring silenced L-galactone-1,4-lactone dehydrogenase (L-GalLDH) activity, it was demonstrated that such dysfunction is dependent on this enzyme activity. The capacity of alternative respiration was strongly decreased by L-GalL, probably mediated by redox-inactivation of the alternative oxidase (AOX) enzyme. Although, alternative respiration was shown to be the key factor that helps support AsA synthesis in dysfunctional mitochondria. Experiments with respiratory inhibitors showed that ROS formation and mitochondrial dysfunction were more associated with the decline in the activities of COX (cytochrome oxidase) and particularly AOX than with the lower activities of respiratory complexes I and III. The application of high L-GalL concentrations induced proteomic changes that indicated alterations in proteins related to oxidative stress and energetic status. However, supra-optimal L-GalL concentration was not deleterious for plants. Instead, the L-GalLDH activity could be positive. Indeed, it was found that wild type plants performed better growth than L-GalLDH-RNAi plants in response to high non-physiological L-GalL concentrations.

Environmental impact of combustion of ethanolic biodiesel/diesel blends from several feedstocks on the gas emission levels in the atmosphere.

The aim of this work was to evaluate simultaneously the effect of produced ethanolic biodiesel from several feedstocks (soybean, crambe, macaw, sunflower, and waste cooking oil) and engine operational conditions (low and high engine speed) during combustion of biodiesel/diesel blends on the N2O, NOx, NO, CO2, and CO emission levels in the atmosphere. The biodiesel samples were prepared in one and/or two reaction steps, according to the acid index of each raw material, by esterification using H2SO4 and/or chemical transesterification using sodium ethoxide, both, through ethanolic route. The quality of the produced biodiesels was confirmed by ASTM/EN specifications. Then, biodiesel/diesel blends were prepared according to the following proportions: 10% (B10), 15% (B15), 25% (B25), and 50% (B50). In general way, all raw materials under combustion at low and high engine speed contributed to the formation of NOx and this effect was more drastically increased as the biodiesel concentration in the blends increases. N2O presented a similar behavior except for blends containing crambe and macaw biodiesel whose emissions were slightly reduced as a function of biodiesel content in these blends. Then, Principal component analysis (PCA) was applied to discriminate the effect of engine operating conditions, biodiesel kind, and biodiesel content in the blends during their combustion on the exhaust emissions. The attained results point to crambe and macaw as more environmentally sustainable feedstocks for biodiesel production because they generate less greenhouse gas emissions. These results are particularly attractive considering that, both, crambe and macaw are non-edible feedstocks with great potential for biodiesel production.

Photodegradation of ethylene by use of TiO2 sol-gel on polypropylene and on glass for application in the postharvest of papaya fruit.

The papaya is a commercially important fruit commodity worldwide. Being a climacteric fruit, it is highly perishable. Thus, for the transportation of papaya fruit for long distances without loss of quality, it is necessary to avoid the autocatalytic effect of ethylene in accelerating the ripening of the fruit. This work addresses the application of heterogeneous photocatalysis to the degradation of ethylene. A TiO2 sol-gel supported on polypropylene (PP) and on glass was used as the catalytic material, and a UV-A lamp was employed as the radiation source. Initially, a concentration of 500 ppbv ethylene was exposed to the catalyst material irradiated by UV-A radiation. A sensitive photoacoustic spectrometer was used to monitor the photocatalytic activity. The TiO2 sol-gel supported on the glass substrate was more efficient than on the PP in degrading the ethylene. Under direct UV-A exposure, the skin appearance of 'Golden' papaya was damaged, depreciating the fruit quality and thus preventing its commercialization. However, the feasibility of the heterogeneous photocatalysis to preserve the fruit quality was achieved when ethylene was removed from the storage ambient using fans, and then, this plant hormone was degraded by a reactor set apart in a ventilation closed system.