•Thiophenols and napthalenethiols were present in ashy flavor standard.•Thiophenols were found in higher concentrations in wines made from smoke exposed grapes.•A combination of thiophenols and ...phenols resulted in ashy flavors in wine.
Grapes exposed to wildfire smoke can develop reduce wine quality, imparting unpleasant smokey and ashy flavors. Research has primarily focused on the increased concentration of volatile phenols (VPs) in grapes and wine acquired from smoke. This study was undertaken to determine the chemical compounds that cause the ashy flavor in wines produced from smoke exposed grapes. The chemical composition of a tasting standard produced from charred leeks was determined using UPLC-QToF/MS. Several thiol derivatives were identified. Analyses of smoke-impacted wines and grapes revealed the presence of thiophenols, napthalene thiols, and additional thiol-derived compounds. LC-MS/MS of wines produced from smoke-exposed grapes showed higher concentrations of thioguaiacol and thiocresols. Chemical causation of smoky and ashy flavors by these compounds was investigated using sensory descriptive analysis. Wines with both thiophenols and VPs were described as ashy and smokey, contributing to more than 90% total variance for each wine.
Modelling-based studies to assess the extent and magnitude of ozone (O
3) risk to agriculture in Asia suggest that yield losses of 5–20% for important crops may be common in areas experiencing ...elevated O
3 concentrations. These assessments have relied on European and North American dose–response relationships and hence assumed an equivalent Asian crop response to O
3 for local cultivars, pollutant conditions and climate. To test this assumption we collated comparable dose–response data derived from fumigation, filtration and EDU experiments conducted in Asia on wheat, rice and leguminous crop species. These data are pooled and compared with equivalent North American dose–response relationships. The Asian data show that at ambient O
3 concentrations found at the study sites (which vary between ∼35–75 ppb 4–8 h growing season mean), yield losses for wheat, rice and legumes range between 5–48, 3–47 and 10–65%, respectively. The results indicate that Asian grown wheat and rice cultivars are more sensitive to O
3 than the North American dose–response relationships would suggest. For legumes the scatter in the data makes it difficult to reach any equivalent conclusion in relative sensitivities. As such, existing modelling-based risk assessments may have substantially underestimated the scale of the problem in Asia through use of North American derived dose–response relationships.
Two very different types of approaches are currently in use today for indicating risk of ozone damage to vegetation in Europe. One approach is the so-called AOTX (accumulated exposure over threshold ...of
X
ppb) index, which is based upon ozone concentrations only. The second type of approach entails an estimate of the amount of ozone entering via the stomates of vegetation, the AFstY approach (accumulated stomatal flux over threshold of
Y
nmol
m
−2
s
−1). The EMEP chemical transport model is used to map these different indicators of ozone damage across Europe, for two illustrative vegetation types, wheat and beech forests. The results show that exceedences of critical levels for either type of indicator are widespread, but that the indicators give very different spatial patterns across Europe. Model simulations for year 2020 scenarios suggest reductions in risks of vegetation damage whichever indicator is used, but suggest that AOT40 is much more sensitive to emission control than AFstY values.
Model calculations of AOT40 and AFstY show very different spatial variations in the risks of ozone damage to vegetation.
The occurrence of surface melt in Antarctica has hitherto been associated with the austral summer season, when the dominant source of melt energy is provided by solar radiation. We use in situ and ...satellite observations from a previously unsurveyed region to show that events of intense surface melt on Larsen C Ice Shelf occur frequently throughout the dark Antarctic winter, with peak intensities sometimes exceeding summertime values. A regional atmospheric model confirms that in the absence of solar radiation, these multiday melt events are driven by outbreaks of warm and dry föhn wind descending down the leeside of the Antarctic Peninsula mountain range, resulting in downward turbulent fluxes of sensible heat that drive sustained surface melt fluxes in excess of 200 W/m2. From 2015 to 2017 (including the extreme melt winter of 2016), ∼23% of the annual melt flux was produced in winter, and spaceborne observations of surface melt since 2000 show that wintertime melt is widespread in some years. Winter melt heats the firn layer to the melting point up to a depth of ∼3 m, thereby facilitating the formation of impenetrable ice layers and retarding or reversing autumn and winter cooling of the firn. While the absence of a trend in winter melt is consistent with insignificant changes in the observed Southern Hemisphere atmospheric circulation during winter, we anticipate an increase in winter melt as a response to increasing greenhouse gas concentration.
Plain Language Summary
Around the coast of Antarctica, it gets warm enough in summer for snow to start melting, and the sun provides most of the energy for that melt. Almost all meltwater refreezes in the snowpack, but especially on floating glaciers in Antarctica, it has been observed that meltwater forms large ponds. The pressure exerted by these ponds may have led to ice shelves collapsing into numerous icebergs in recent decades. It is therefore important to understand how much meltwater is formed. To find out, we installed an automatic weather station on a glacier in Cabinet Inlet, in the Antarctic Peninsula in 2014. The station recorded temperatures well above the melting point even in winter. The occurrence of winter melt is confirmed by satellite images and by thermometers buried in the snow, which measured a warming of the snow even at 3 m depth. Between 2014 and 2017, about 23% of all melt in Cabinet Inlet occurred in winter. Winter melt is due to warm winds that descend from the mountains, known as föhn. We have not seen the amount of winter melt increasing since 2000. However, we expect winter melt to happen more frequently if greenhouse gas continues to accumulate in the atmosphere.
Key Points
Wintertime surface melt occurs frequently in the Antarctic Peninsula
Winter melt heats the firn to a depth of about 3 m, retarding or reversing winter cooling
Increased greenhouse gas concentrations could increase the occurrence of winter surface melt
Electrocorticography (ECoG), used as a neural recording modality for brain-machine interfaces (BMIs), potentially allows for field potentials to be recorded from the surface of the cerebral cortex ...for long durations without suffering the host-tissue reaction to the extent that it is common with intracortical microelectrodes. Though the stability of signals obtained from chronically implanted ECoG electrodes has begun receiving attention, to date little work has characterized the effects of long-term implantation of ECoG electrodes on underlying cortical tissue.
We implanted and recorded from a high-density ECoG electrode grid subdurally over cortical motor areas of a Rhesus macaque for 666 d.
Histological analysis revealed minimal damage to the cortex underneath the implant, though the grid itself was encapsulated in collagenous tissue. We observed macrophages and foreign body giant cells at the tissue-array interface, indicative of a stereotypical foreign body response. Despite this encapsulation, cortical modulation during reaching movements was observed more than 18 months post-implantation.
These results suggest that ECoG may provide a means by which stable chronic cortical recordings can be obtained with comparatively little tissue damage, facilitating the development of clinically viable BMI systems.
Maternal obesity is a global problem that increases the risk of short‐ and long‐term adverse outcomes for mother and child, many of which are linked to gestational diabetes mellitus. Effective ...treatments are essential to prevent the transmission of poor metabolic health from mother to child. Metformin is an effective glucose lowering drug commonly used to treat gestational diabetes mellitus; however, its wider effects on maternal and fetal health are poorly explored. In this study we used a mouse (C57Bl6/J) model of diet‐induced (high sugar/high fat) maternal obesity to explore the impact of metformin on maternal and feto‐placental health. Metformin (300 mg kg−1 day−1) was given to obese females via the diet and was shown to achieve clinically relevant concentrations in maternal serum (1669 ± 568 nM in late pregnancy). Obese dams developed glucose intolerance during pregnancy and had reduced uterine artery compliance. Metformin treatment of obese dams improved maternal glucose tolerance, reduced maternal fat mass and restored uterine artery function. Placental efficiency was reduced in obese dams, with increased calcification and reduced labyrinthine area. Consequently, fetuses from obese dams weighed less (P < 0.001) at the end of gestation. Despite normalisation of maternal parameters, metformin did not correct placental structure or fetal growth restriction. Metformin levels were substantial in the placenta and fetal circulation (109.7 ± 125.4 nmol g−1 in the placenta and 2063 ± 2327 nM in fetal plasma). These findings reveal the distinct effects of metformin administration during pregnancy on mother and fetus and highlight the complex balance of risk vs. benefits that are weighed in obstetric medical treatments.
Key points
Maternal obesity and gestational diabetes mellitus have detrimental short‐ and long‐term effects for mother and child.
Metformin is commonly used to treat gestational diabetes mellitus in many populations worldwide but the effects on fetus and placenta are unknown.
In a mouse model of diet‐induced obesity and glucose intolerance in pregnancy we show reduced uterine artery compliance, placental structural changes and reduced fetal growth.
Metformin treatment improved maternal metabolic health and uterine artery compliance but did not rescue obesity‐induced changes in the fetus or placenta. Metformin crossed the placenta into the fetal circulation and entered fetal tissue.
Metformin has beneficial effects on maternal health beyond glycaemic control. However, despite improvements in maternal physiology, metformin did not prevent fetal growth restriction or placental ageing. The high uptake of metformin into the placental and fetal circulation highlights the potential for direct immediate effects of metformin on the fetus with possible long‐term consequences postnatally.
figure legend Obesogenic diet during pregnancy leads to impaired metabolic health in the mother and reduced fetal growth and placental pathologies. Maternal metabolic health can be markedly improved by metformin treatment; however, this is not the case for fetal and placental health and metformin reaches the placenta and fetal circulation, which could have direct short‐ and long‐term effects.
A model has been developed to estimate stomatal ozone flux across Europe for a number of important species. An initial application of this model is illustrated for two species, wheat and beech. The ...model calculates ozone flux using European Monitoring and Evaluation Programme (EMEP) model ozone concentrations in combination with estimates of the atmospheric, boundary layer and stomatal resistances to ozone transfer. The model simulates the effect of phenology, irradiance, temperature, vapour pressure deficit and soil moisture deficit on stomatal conductance. These species-specific microclimatic parameters are derived from meteorological data provided by the Norwegian Meteorological Institute (DNMI), together with detailed land-use and soil type maps assembled at the Stockholm Environment Institute (SEI). Modelled fluxes are presented as mean monthly flux maps and compared with maps describing equivalent values of AOT40 (accumulated exposure over threshold of 40 ppb or nl l(-1)), highlighting the spatial differences between these two indices. In many cases high ozone fluxes were modelled in association with only moderate AOT40 values. The factors most important in limiting ozone uptake under the model assumptions were vapour pressure deficit (VPD), soil moisture deficit (for Mediterranean regions in particular) and phenology. The limiting effect of VPD on ozone uptake was especially apparent, since high VPDs resulting in stomatal closure tended to co-occur with high ozone concentrations. Although further work is needed to link the ozone uptake and deposition model components, and to validate the model with field measurements, the present results give a clear indication of the possible implications of adopting a flux-based approach for future policy evaluation.
Two different indices have been proposed for estimation of the risk caused to forest trees across Europe by ground-level ozone, (i) the concentration based AOT40 index (Accumulated Over a Threshold ...of 40
ppb) and (ii) the recently developed flux based AFst
Y index (Accumulated stomatal Flux above a flux threshold
Y). This paper compares the AOT40 and AFst
Y indices for three forest trees species at different locations in Europe. The AFst
Y index is estimated using the DO
3SE (Deposition of Ozone and Stomatal Exchange) model parameterized for Scots pine (
Pinus sylvestris), beech (
Fagus sylvatica) and holm oak (
Quercus ilex). The results show a large difference in the perceived O
3 risk when using AOT40 and AFst
Y indices both between species and regions. The AOT40 index shows a strong north-south gradient across Europe, whereas there is little difference between regions in the modelled values of AFst
Y. There are significant differences in modelled AFst
Y between species, which are predominantly determined by differences in the timing and length of the growing season, the periods during which soil moisture deficit limits stomatal conductance, and adaptation to soil moisture stress. This emphasizes the importance of defining species-specific flux response variables to obtain a more accurate quantification of O
3 risk.
A new flux-based model provides a revised assessment of risks of ozone impacts to European forests.
Gestational hypoxia adversely affects uterine artery function, increasing complications. However, an effective therapy remains unidentified. Here, we show in rodent uterine arteries that hypoxic ...pregnancy promotes hypertrophic remodelling, increases constrictor reactivity via protein kinase C signalling, and triggers compensatory dilatation via nitric oxide‐dependent mechanisms and stimulation of large conductance Ca2+‐activated K+‐channels. Maternal in vivo oral treatment with the mitochondria‐targeted antioxidant MitoQ in hypoxic pregnancy normalises uterine artery reactivity and prevents vascular remodelling. From days 6–20 of gestation (term ∼22 days), female Wistar rats were randomly assigned to normoxic or hypoxic (13–14% O2) pregnancy ± daily maternal MitoQ treatment (500 µm in drinking water). At 20 days of gestation, maternal, placental and fetal tissue was frozen to determine MitoQ uptake. The uterine arteries were harvested and, in one segment, constrictor and dilator reactivity was determined by wire myography. Another segment was fixed for unbiased stereological analysis of vessel morphology. Maternal administration of MitoQ in both normoxic and hypoxic pregnancy crossed the placenta and was present in all tissues analysed. Hypoxia increased uterine artery constrictor responses to norepinephrine, angiotensin II and the protein kinase C activator, phorbol 12,13‐dibutyrate. Hypoxia enhanced dilator reactivity to sodium nitroprusside, the large conductance Ca2+‐activated K+‐channel activator NS1619 and ACh via increased nitric oxide‐dependent mechanisms. Uterine arteries from hypoxic pregnancy showed increased wall thickness and MitoQ treatment in hypoxic pregnancy prevented all effects on uterine artery reactivity and remodelling. The data support mitochondria‐targeted therapy against adverse changes in uterine artery structure and function in high‐risk pregnancy.
Key points
Dysfunction and remodelling of the uterine artery are strongly implicated in many pregnancy complications, including advanced maternal age, maternal hypertension of pregnancy, maternal obesity, gestational diabetes and pregnancy at high altitude.
Such complications not only have immediate adverse effects on the growth of the fetus, but also they can also increase the risk of cardiovascular disease in the mother and offspring. Despite this, there is a significant unmet clinical need for therapeutics that treat uterine artery vascular dysfunction in adverse pregnancy.
Here, we show in a rodent model of gestational hypoxia that in vivo oral treatment of the mitochondria‐targeted antioxidant MitoQ protects against uterine artery vascular dysfunction and remodelling, supporting the use of mitochondria‐targeted therapy against adverse changes in uterine artery structure and function in high‐risk pregnancy.
figure legend Moderate hypoxia (13–14% O2) during rat pregnancy programmes uterine artery remodelling and dysfunction via mitochondria derived oxidative stress. The mitochondria‐targeted antioxidant MitoQ treatment prevents the adverse changes in uterine artery structure and function in high‐risk pregnancy.
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