Is the destruction or removal of atmospheric methane a worthwhile option? Nisbet-Jones, Peter B R; Fernandez, Julianne M; Fisher, Rebecca E ...
Philosophical transactions - Royal Society. Mathematical, Physical and engineering sciences/Philosophical transactions - Royal Society. Mathematical, physical and engineering sciences,
01/2022, Letnik:
380, Številka:
2215
Journal Article
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Removing methane from the air is possible, but do the costs outweigh the benefits? This note explores the question of whether removing methane from the atmosphere is justifiable. Destruction of ...methane by oxidation to CO
eliminates 97% of the warming impact on a 100-yr time scale. Methane can be oxidized by a variety of methods including thermal or ultraviolet photocatalysis and various processes of physical, chemical or biological oxidizers. Each removal method has energy costs (with the risk of causing embedded CO
emission that cancel the global warming gain), but in specific circumstances, including settings where air with high methane is habitually present, removal may be competitive with direct efforts to cut fugitive methane leaks. In all cases however, great care must be taken to ensure that the destruction has a net positive impact on the total global warming, and that the resources required would not be better used for stopping the methane from being emitted. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.
The pathogenic bacterium
Vibrio vulnificus
is related to human infections by direct contact with the bacteria or by consuming raw aquacultural products, like oysters and clams. This work aimed to ...measure the effect of the microalga
Isochrysis galbana
on the density of two pathogenic
V. vulnificus
strains when they are co-cultured.
Vibrio vulnificus
strains CICESE-316 and CICESE-325 were inhibited in co-cultures with the microalgae species. The
I. galbana
cell density reached values of 22×10
6
cells mL
−1
after 12 days post-inoculation with
V. vulnificus
. The density of vibrios was monitored in the algae cultures by the membrane filtration method. The initial concentration of each
Vibrio
species in co-cultures was ≥10
4
CFU mL
−1
, and the time required to achieve the inhibition of
V. vulnificus
(counts lower than 0.1 CFU mL
−1
) was 10 days for strain CICESE-316 and 7 days for strain CICESE-325. The undetectable levels of
V. vulnificus
in co-cultures with
I. galbana
were maintained until 12 days after inoculation. We concluded that the results obtained can promote the use of
I. galbana
cultures in aquaculture facilities to reduce the
V. vulnificus
load in the organism with commercial importance, such as bivalve mollusks and fishes.
The effects of light spectra on cell concentration, cell size, biomass production, proximate composition, pigment content, and fatty acid content in
Chlorella vulgaris
during two growth phases were ...measured. Growth rates were higher with white (0.70 division day
−1
) and blue light (0.67 divisions day
−1
). Cell size was greater in the exponential growth with yellow light (16.29 μm) versus blue light (14.26 μm). Higher organic dry weight (ODW) values were observed during exponential growth under green light (70.58 pg cell
−1
) compared with white light (36.56 pg cell
−1
). Proximate composition differed significantly by effect of light spectra and growth phases. Protein content was significantly higher in the exponential growth with white light (34.42%) and green (31.64%) light. Carbohydrate levels were significantly higher during stationary growth under yellow light (27.05%). In the exponential growth, lipid content was significantly higher with blue light (18.74%). Biomass productivity was highest in exponential growth phase with blue light (0.064 gL
-1
day
-1
), meanwhile, in stationary growth phase yellow light (0.031 gL
-1
day
-1
). Chlorophyll a and carotenoid levels were significantly greater during exponential growth with green and yellow lights. Fatty acid content was significantly modified by the light spectra and growth phase. The predominant saturated fatty acid was C:16:0 (palmitic acid), ranging between 10.26 (green light and exponential growth) and 20.01% (white light and stationary growth). The content of C18:1n-9 was higher (28.34 %) with the white light in the stationary growth, and C18:3n-3 content was greater with white (41.41%) and blue light (40.82%) in the exponential growth. It was concluded that blue light is the most suitable condition to induce biomass productivity and lipid content on both growth phases. Blue light during the stationary growth phase induces the production of lipids and saturated fatty acids (SFAs) which are suitable for biodiesel production.
Vibrio alginolyticus, Vibrio campbellii, and Vibrio harveyi were inhibited by Isochrysis galbana in batch cultures. I. galbana reduced the V. alginolyticus, V. campbellii, and V. harveyi counts to ...undetectable levels in 2, 4, and 7 days (<0.01 Vibrio spp. mL⁻¹), respectively, remaining so until the end of the experiment on day 15. Other heterotrophic bacteria reached counts of 10⁶ CFU mL⁻¹ on ZoBell medium at the end of the experiment. Vibrio parahaemolyticus was not inhibited by I. galbana. In all mixed I. galbana and Vibrio spp. cultures, the algal density increased from 3.5 to 4.0 × 10⁷ cells mL⁻¹, higher than that in I. galbana cultures alone, indicating a lack of an inhibitory effect on microalgae in the mixed cultures. The predominant fatty acids (>82 %) of I. galbana during the stationary growth phase were estearidonic (24.3 %), oleic (15.7 %), myristic (13.8 %), docosahexaenoic (11.0 %), palmitic (10.3 %), and α-linolenic (7.2 %) acids. These results demonstrate that I. galbana synthesizes antibacterial fatty acids that inhibit the growth of pathogenic bacteria such as V. alginolyticus, V. campbellii, and V. harveyi.
We determined the effects of two nitrogen sources (ammonium and nitrate) and two irradiance levels (50 and 200 μmol photons m
−2
s
−1
) on the growth rate, cell size, proximate composition, pigment ...content, and photosynthesis of the unicellular red alga,
Porphyridium cruentum
. Irradiance significantly affects growth rate, as well as carbohydrate, protein, and phycoerythrin content. Nitrogen form significantly affects cell size, total dry weight, organic dry weight, ash content, carotene content, phycocyanin content, allophycocyanin content, maximum relative electron transport rate (rETRm), and photosynthetic efficiency (α). However, the irradiance and nitrogen source had significantly interaction with the content of lipids and chlorophyll
a
content, relative electron transport rate (rETR), and irradiance of saturation (I
k
). These findings demonstrate that irradiance and nitrogen source influence the metabolism of
P
.
cruentum
and that the combination of these two variables induces the production of chemical products for biotechnological, aquaculture, and nutraceutical industry.
Diatoms can produce inhibitory compounds against bacteria, constituting an alternative to the use of chemicals to control pathogenic bacterial growth. Antibacterial activity has been detected in ...co-cultures of microalgae-bacteria and extracts. Thus, we evaluated the ability of 6 benthic diatom species to inhibit the growth of Vibrio alginolyticus, V. campbellii, and V. harveyi, which are bacterial species that are pathogenic to mollusks, crustaceans, and fish. Triplicate cultures of benthic diatoms were inoculated with each individual Vibrio species, and the density of microalgae cells, vibrios, and heterotrophic bacteria was estimated at baseline (0h), 24, 48, 72, 96, 168h post-inoculation, and when the diatom cultures reached the stationary growth phase. Significant differences in the growth of each diatom species were observed, depending on the Vibrio species that was inoculated, and in all cultures, the density of Vibrio cells decreased, even to undetectable levels (<0.01Vibrio cellsmL−1), after 4, 7, and 16days post-inoculation. Initial bacterial counts in the diatom cultures were on the order of 103 (Colony Forming Units)CFUmL−1, reaching 106 to 107CFUmL−1 by the end. The concentration of bacteria in the diatom cultures was similar between co-cultures and control treatments, indicating that the inhibitory effects of the diatom strains were specific for Vibrio species. We conclude that the diatom species that we tested control the concentration of pathogenic vibrios, presumably through the production of antibacterial compounds. These findings should encourage the use of diatom cultures as a feeding source and to control the density of pathogenic Vibrio species in culture systems, adding diatom species to culture water as a “green water” technique.
•Benthic diatoms inhibit the growth of three species of pathogenic vibrios.•The growth of diatom species was affected by the addition of Vibrio spp.•Anti-vibrio effect is conserved until diatoms reached the stationary growth phase.
Diatoms, such as Chaetoceros, grow in a mutualistic relationship with bacteria. However, in some cases, it is necessary to grow them in bacteria-free cultures. To reduce bacterial load, antibiotics ...are used, and on certain occasions it is necessary to use a mixture with more than one antibiotic. This work aimed to obtain a quick and effective protocol to reduce the bacterial load and evaluate the response of three Chaetoceros species with aquacultural importance. Single and mix antibiotics were used. Microalgal and bacterial growth was measured. The growth parameters for diatoms showed that the significantly highest cell concentration was for C. muelleri (3.15 x106 cells mL-1) and the lowest values to C. calcitrans (2.98 x106 cells mL-1). The significantly highest growth rate was for C. calcitrans (0.77 divisions per day), and the lowest values for Chaetoceros sp. (0.60 divisions per day). The growth parameters for heterotrophic bacteria showed that the significantly highest bacterial load was for Chaetoceros sp. (19.16 x106 CFU (Colony-Forming Units) mL-1) and the lowest values were for C. calcitrans (12.23 x106 CFU mL-1). The growth rate of the heterotrophic bacteria present in Chaetoceros cultures was similar among the three studied species. Streptomycin® and sulfate G41® produced a partial reduction of bacterial load. The most effective treatment for all three species was the use of an antibiotic mix composed of ampicillin® (250 μg mL-1), kanamycin® (200 μg mL-1), neomycin® (50 μg mL-1), and streptomycin® (100 μg mL-1) for three days. The mix prepared with the highest antibiotic concentration produced a reduction of bacteria (100%) for three days; however, it also induced a significant reduction of the growth of the three Chaetoceros species.
We present the combined results on electron-pair production in 158 GeV/n Pb-Au (\(\sqrt{s}\) = 17.2 GeV) collisions taken at the CERN SPS in 1995 and 1996, and give a detailed account of the data ...analysis. The enhancement over the reference of neutral meson decays amounts to a factor of 2.31 \(\pm0.19 (stat.)\pm0.55 (syst.)\pm0.69 (decays)\) for semi-central collisions (28\(\%\)\(\sigma/\sigma_{geo}\)) when yields are integrated over m > 200 MeV/c2 in invariant mass. The measured yield, its stronger-than-linear scaling with \(N_{\rm ch}\), and the dominance of low pair pt strongly suggest an interpretation as thermal radiation from pion annihilation in the hadronic fireball. The shape of the excess centring at \(m\approx\) 500 MeV/c2, however, cannot be described without strong medium modifications of the \(\rho\) meson. The results are put into perspective by comparison to predictions from Brown-Rho scaling governed by chiral symmetry restoration, and from the spectral-function many-body treatment in which the approach to the phase boundary is less explicit.
To perform the construct validity and the internal consistency of the Maternal Breastfeeding Evaluation Scale tool, aiming at its application in the Brazilian population.
Cross-sectional study that ...applied the tool to 287 Brazilian women 30 days after childbirth. Main component analysis with varimax rotation was used for the factor analysis, verifying the number of subscales and the maintenance or extraction of the components. Four hypotheses were tested using the unpaired Student's t-test for construct validation. The reliability analysis was performed using Cronbach's alpha coefficient.
The exploratory factor analysis identified the need to exclude an item and to reformulate the subscales. The results of the construct validity showed that all hypotheses proposed were confirmed: women who were breastfeeding, those who were exclusively breastfeeding, those who did not have problems related to breastfeeding, and those who intended to breastfeed for at least 12 months achieved significantly higher mean values in the scale. The tool showed adequate internal consistency (Cronbach's alpha=0.88, 95% CI: 0.86–0.90), as did the pleasure and fulfillment of the maternal role subscales (0.92, 95% CI: 0.91–0.93%); child growth, development, and satisfaction (0.70; 95% CI: 0.65–0.75); and maternal physical, social, and emotional aspects (0.75, 95% CI: 0.70–0.79).
The validation process of the Brazilian version of the Maternal Breastfeeding Evaluation Scale tool showed that it is valid and reliable tool to be applied to the Brazilian population.
Realizar a validação de constructo e avaliar a consistência interna do instrumento Maternal Breastfeeding Evaluation Scale, visando à sua aplicação na população brasileira.
Estudo transversal com aplicação do instrumento a 287 mulheres brasileiras após 30 dias do nascimento da criança. Para a análise fatorial utilizou-se a análise de componentes principais com rotação varimax, verificando o número de subescalas e a manutenção ou extração dos componentes. Para a validação de constructo quatro hipóteses foram testadas pelo teste T-student não pareado. A análise de confiabilidade foi realizada utilizando o coeficiente de alfa de Cronbach.
A análise fatorial exploratória identificou a necessidade de exclusão de um item e a reformulação das subescalas. Os resultados da validade de constructo mostraram que todas as hipóteses propostas foram confirmadas: as mulheres que estavam amamentando, as que estavam em amamentação exclusiva, as que não apresentavam problemas relacionados à amamentação e aquelas com intenção de amamentar por pelo menos 12 meses apresentaram valores médios significativamente superiores na escala. O instrumento apresentou consistência interna adequada (alfa de Cronbach=0,88; IC95%: 0,86-0,90), assim como as subescalas prazer e realização do papel materno (0,92; IC95%: 0,91-0,93), crescimento, desenvolvimento e satisfação infantil (0,70; IC95%: 0,65-0,75) e aspectos físico, social e emocional materno (0,75; IC95%: 0,70-0,79).
O processo de validação do instrumento Maternal Breastfeeding Evaluation Scale/BRASIL constatou que ele é válido e confiável para ser aplicado à população brasileira.
Variant Philadelphia (Ph) chromosome can be observed in 5–10 % of chronic myelogenous leukemia (CML) patients. However, there are only a few studies which have analyzed the prognostic implications of ...these complex translocations in CML patients after the advent of imatinib mesylate and the results found are conflicting. We investigated the clinical features and cytogenetic response of Brazilian chronic phase (CP) CML patients with variant Ph treated with imatinib mesylate. Among 93 CP CML patients, eight (8.6 %) exhibited complex translocations, involving one (
n
= 6), two (
n
= 1), or three (
n
= 1) additional chromosomes. At 6, 12, and 18 months, a complete cytogenetic response was observed in 100 % of variant Ph patients, respectively. No significant difference was found between variant Ph and standard translocation patients regarding the response to IM treatment at 6, 12, and 18 months. Likewise, there was no statistically significant difference between the two groups concerning the overall survival, failure-free survival, progression-free survival, and event-free survival. The results obtained in our study, despite our sample size, suggest, in agreement to other data found in the literature, that the presence of variant Philadelphia chromosome does not bestow a prognostic disadvantage when compared to the group with classic Ph. This observation does not suggest the need to adjust the treatment protocol due to the presence of variant Ph. However, further studies with larger sample sizes and evaluating both the cytogenetic and molecular response to IM treatment should be conducted to confirm our findings.
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