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► A review of the main technologies studied for producing biodiesel at lower cost is reported. ► The possibility of using new feedstock cheaper and not competing with food is ...mentioned. ► The possibility of intensify the traditional process catalyzed by homogeneous alkaline catalyst is reviewed. ► The main heterogeneous basic and acid catalysts studied in the literature are discussed and compared. ► New uses for the by-product glycerol reported in the literature are examined and discussed.
Biodiesel is a fuel safe, renewable, non-toxic, biodegradable and much less contaminant for the environment than conventional diesel. Moreover, it represents a strategic source of energy especially for the countries that have not oilfields. For these reasons, even if the cost of biodiesel is still greater than diesel from petroleum, many governments sustain this production. The cost of biodiesel is mainly affected by the cost of the feedstock but also an improvement of the adopted technology can contribute in reducing the costs. Therefore, it is imperative: to employ less expensive feedstock, that is, unrefined or waste oils; to use not edible oil coming from alternative sources as, for example, algae or Jathropa Curcas; to improve the actual technology based on the use of homogeneous alkaline catalysts through a better understanding of the reaction mechanism, to develop new biphasic kinetic models; to adopt techniques of process intensification; to introduce the use of heterogeneous catalysts, possibly finding a catalyst promoting in one step both esterification of free fatty acids and transesterification of tri-glycerides; to find new remunerative uses for the by-product glycerol. In this paper, all the mentioned aspects will be considered by reporting some of the most relevant results obtained in the last years.
We analyze the complete set of in-situ meteorological data obtained from the Viking landers in the 1970s to todays Curiosity rover to review our understanding of the modern near-surface climate of ...Mars, with focus on the dust, CO2 and H2O cycles and their impact on the radiative and thermodynamic conditions near the surface. In particular, we provide values of the highest confidence possible for atmospheric opacity, atmospheric pressure, near-surface air temperature, ground temperature, near-surface wind speed and direction, and near-surface air relative humidity and water vapor content. Then, we study the diurnal, seasonal and interannual variability of these quantities over a span of more than twenty Martian years. Finally, we propose measurements to improve our understanding of the Martian dust and H2O cycles, and discuss the potential for liquid water formation under Mars present day conditions and its implications for future Mars missions.
Patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) are often managed conservatively. Clinical practice guidelines recommend treating these patients with the same pharmacological drugs ...as those who receive invasive treatment. We analyze the use of new antiplatelet drugs (NADs) and other recommended treatments in people discharged following an NSTE-ACS according to the treatment strategy used, comparing the medium-term prognosis between groups.
Prospective observational multicenter registry study in 1717 patients discharged from hospital following an ACS; 1143 patients had experienced an NSTE-ACS. We analyzed groups receiving the following treatment: No cardiac catheterization (NO CATH): n = 134; 11.7%; Cardiac catheterization without revascularization (CATH-NO REVASC): n = 256; 22.4%; percutaneous coronary intervention (PCI): n = 629; 55.0%; and coronary artery bypass graft (CABG): n = 124; 10.8%. We assessed major adverse cardiovascular events (MACE), all-cause mortality, and hemorrhagic complications at one year.
NO CATH was the oldest, had the most comorbidities, and was at the highest risk for ischemic and hemorrhagic events. Few patients who were not revascularized with PCI received NADs (NO CATH: 3.7%; CATH-NO REVASC: 10.6%; PCI: 43.2%; CABG: 3.2%; p<0.001). Non-revascularized patients also received fewer beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARB), and statins (p<0.001). At one year, MACE incidence in NO CATH group was three times that of the other groups (30.1%, p<0.001), and all-cause mortality was also much higher (26.3%, p<0.001). There were no significant differences in hemorrhagic events. Belonging to NO CATH group was an independent predictor for MACE at one year in the multivariate analysis (HR 2.72, 95% CI 1.29-5.73; p = 0.008).
Despite current invasive management of NSTE-ACS, patients not receiving catheterization are at very high risk for under treatment with recommended drugs, including NADs. Their medium-term prognosis is poor, with high mortality. Patients treated with PCI receive better pharmacological management, with high use of NADs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In situ measurements by the Curiosity rover provide a unique opportunity for studying the effects of dust on assets placed at the surface of Mars. Here we use in situ measurements of solar UV ...radiation to quantify the seasonal and interannual variability of dust accumulation on the sensor on the rover deck. We show that the amount of dust accumulated on the sensor follows a seasonal cycle, with net dust removal during the perihelion season until L
~ 300°, and net dust deposition until the end of the aphelion season (L
~ 300°-180°). We use independent in situ measurements of atmospheric opacity and pressure perturbations in combination with numerical modeling, showing that daytime convective vortices and nighttime winds are likely responsible for the seasonal dust cleaning, with the role of nighttime wind being more important in Martian Year (MY) 32 than in MY 33 and that of daytime convective vortices being more important in MY 33 than in MY 32. The fact that the UV sensor is cleaner in MY 33 than in MY 32 indicates that natural cleaning events make solar energy an excellent candidate to power extended (multiannual) Mars missions at similar latitudes as the Curiosity rover.
We quantify the effect of dust accumulation at Jezero crater by means of a Dust Correction Factor (DCF) for the solar radiation measured by the photodiodes of the Radiation and Dust Sensor of the ...Mars 2020 mission. After one Mars Year, dust on the photodiode surface attenuated 25%–30% of the incoming solar radiation. The DCF did not decrease monotonically; we use a model to reproduce its evolution and to derive dust deposition and lifting rates, showing that dust removal is 9 times larger at Jezero crater than at InSight's location in western Elysium Planitia. The model fit obtained using observed opacities is further improved when fed with dust sedimentation rates simulated by a GCM that considers a particle size distrtibution. Projections show seasonal net dust removal, being encouraging for the long‐term survival of solar‐powered missions to Jezero or similarly active dust lifting regions.
Plain Language Summary
Dust is ubiquitous in the Martian atmosphere, accumulating on both natural and artificial surfaces. Dust particularly affects the performance and lifetime of missions: the termination of InSight and MER‐B operations are recent examples. Dust accumulation shows a seasonal behavior, and attenuated 25%–30% of the incoming solar radiation on Perseverance after the first Mars Year of the mission. Dust removal is almost 10 times larger than at InSight's location: projections indicate that surfaces at Jezero will be periodically partially cleaned. The estimations of the effect of the accumulated dust as a function of time are encouraging for solar‐powered missions to regions with similar amounts of dust lifting, which might be determined from orbital data on where dust storms originate, dust devils or their tracks are found, or seasonal albedo changes are noted. In addition, the quantification of the effect of accumulated enables future studies requiring more accurate knowledge of incoming solar radiation at the surface.
Key Points
We present the evolution of dust accumulation at Jezero crater for more than one Mars Year
We derive dust deposition and removal rates: removal is 9 times more efficient than at the InSight location in western Elysium Planitia
Projections show that surfaces at Jezero will experience seasonal net dust removal, encouraging solar‐powered missions
The
Mars Regional Atmospheric Modeling System
(
MRAMS
) and a nested simulation of the
Mars Weather Research and Forecasting model
(
MarsWRF
) are used to predict the local meteorological conditions ...at the
Mars 2020 Perseverance
rover landing site inside Jezero crater (Mars). These predictions are complemented with the
COmplutense and MIchigan MArs Radiative Transfer
model (
COMIMART
) and with the local
Single Column Model
(
SCM
) to further refine predictions of radiative forcing and the water cycle respectively. The primary objective is to facilitate interpretation of the meteorological measurements to be obtained by the
Mars Environmental Dynamics Analyzer
(
MEDA
) aboard the rover, but also to provide predictions of the meteorological phenomena and seasonal changes that might impact operations, from both a risk perspective and from the perspective of being better prepared to make certain measurements. A full diurnal cycle at four different seasons (
L
s
0
∘
,
90
∘
,
180
∘
, and
270
∘
) is investigated. Air and ground temperatures, pressure, wind speed and direction, surface radiative fluxes and moisture data are modeled. The good agreement between observations and modeling in prior works Pla-Garcia et al. in Icarus 280:103–113,
2016
; Newman et al. in Icarus 291:203–231,
2017
; Vicente-Retortillo et al. in Sci. Rep. 8(1):1–8,
2018
; Savijärvi et al. in Icarus,
2020
provides confidence in utilizing these models results to predict the meteorological environment at
Mars 2020 Perseverance
rover landing site inside Jezero crater. The data returned by
MEDA
will determine the extent to which this confidence was justified.
Rovers and landers on Mars have experienced local, regional, and planetary‐scale dust storms. However, in situ documentation of active lifting within storms has remained elusive. Over 5–11 January ...2022 (LS 153°–156°), a dust storm passed over the Perseverance rover site. Peak visible optical depth was ∼2, and visibility across the crater was briefly reduced. Pressure amplitudes and temperatures responded to the storm. Winds up to 20 m s−1 rotated around the site before the wind sensor was damaged. The rover imaged 21 dust‐lifting events—gusts and dust devils—in one 25‐min period, and at least three events mobilized sediment near the rover. Rover tracks and drill cuttings were extensively modified, and debris was moved onto the rover deck. Migration of small ripples was seen, but there was no large‐scale change in undisturbed areas. This work presents an overview of observations and initial results from the study of the storm.
Plain Language Summary
Mars commonly has local and regional dust storms, some of which grow into global dust storms. Until now, no lander or rover on Mars has observed the meteorology and processes within an active lifting storm center. The Perseverance rover experienced a large regional storm in Jezero crater over six sols (Martian days) in January 2022. It documented active dust lifting and winds reshaping the Martian sediment. Winds increased as the storm approached but were only directly monitored until the afternoon of the first sol, when the wind sensor failed during high winds. Winds, even after the loss of the wind sensor, were powerful enough to blow sand and lift dust around the rover. Rover imaging showed 21 dust devils and other dust lifting events near noon of the first sol. Images of the rover and terrain showed that there were several incidents of sediment mobilization immediately around the rover. Rover tracks were erased or heavily modified, cuttings from a recent drilling were removed, and sediment was deposited across the rover's deck. The changes wrought by the storm were concentrated on areas where the rover had previously modified the terrain, except for sand motion including the migration of small sand ripples.
Key Points
The Perseverance rover documented the meteorology and effects of a dust storm as it passed over Jezero crater, Mars
The storm brought damaging winds and wide‐spread dust lifting, while modifying the pressure amplitudes and thermal cycle at the site
Winds extensively modified previously disturbed areas, while sand motion and small‐scale ripple migration occurred all around the rover
Human dental mesenchymal stem cells (MSCs) are considered as highly accessible and attractive MSCs for use in regenerative medicine, yet some of their features are not as well characterized as other ...MSCs. Hypoxia-preconditioning and hypoxia-inducible factor 1 (HIF-1) alpha overexpression significantly improves MSC therapeutics, but the mechanisms involved are not fully understood. In the present study, we characterize immunomodulatory properties of dental MSCs and determine changes in their ability to modulate adaptive and innate immune populations after HIF-1 alpha overexpression.
Human dental MSCs were stably transduced with green fluorescent protein (GFP-MSCs) or GFP-HIF-1 alpha lentivirus vectors (HIF-MSCs). A hypoxic-like metabolic profile was confirmed by mitochondrial and glycolysis stress test. Capacity of HIF-MSCs to modulate T-cell activation, dendritic cell differentiation, monocyte migration, and polarizations towards macrophages and natural killer (NK) cell lytic activity was assessed by a number of functional assays in co-cultures. The expression of relevant factors were determined by polymerase chain reaction (PCR) analysis and enzyme-linked immunosorbent assay (ELISA).
While HIF-1 alpha overexpression did not modify the inhibition of T-cell activation by MSCs, HIF-MSCs impaired dendritic cell differentiation more efficiently. In addition, HIF-MSCs showed a tendency to induce higher attraction of monocytes, which differentiate into suppressor macrophages, and exhibited enhanced resistance to NK cell-mediated lysis, which supports the improved therapeutic capacity of HIF-MSCs. HIF-MSCs also displayed a pro-angiogenic profile characterized by increased expression of CXCL12/SDF1 and CCL5/RANTES and complete loss of CXCL10/IP10 transcription.
Immunomodulation and expression of trophic factors by dental MSCs make them perfect candidates for cell therapy. Overexpression of HIF-1 alpha enhances these features and increases their resistance to allogenic NK cell lysis and, hence, their potential in vivo lifespan. Our results further support the use of HIF-1 alpha-expressing dental MSCs for cell therapy in tissue injury and immune disorders.
Introduction
Paediatric and adult psychiatric emergency department (ED) visits decreased during the initial COVID-19 pandemic outbreak. Long-term consequences of the pandemic will include increases ...in mental healthcare needs especially among especially vulnerable groups such as children and adolescents.
Objectives
This study examined changes in the number of overall and diagnosis-specific mental health ED visits among patients aged <18 years following onset of the COVID-19 pandemic in Madrid, Spain.
Methods
We used electronic health records to extract the monthly numbers of total and diagnosis-specific mental health ED visits among patients aged <18 years, between October 2018 and April 2021, to La Paz University Hospital. We conducted interrupted time-series analyses and compared trends before and after the day of the first ED COVID-19 case (1
st
March 2020).
Results
In March 2020, there was a marked initial decrease of -12.8 (95%CI -21.9, -7.9) less monthly mental health ED visits. After April 2020, there was a subsequent increasing trend of 3.4 (95%CI 2.6, 4.2) additional monthly mental health ED visits.
Conclusions
After onset of the COVID-19 pandemic, there was an increase in paediatric psychiatric ED visits, especially due to suicide-related reasons. These data reinforce the crucial role of the ED in the management of acute mental health problems among youth and highlight the need for renovated efforts to enhance access to care outside of and during acute crises during the pandemic and its aftermath.
Disclosure
No significant relationships.
Four strategies of deficit irrigation based on a different water-stress ratio (WSR) applied in each phenological stage, and a control treatment were implemented in 11-year-old citrus trees (
Citrus ...sinensis L. Osb. Cv.
Navelina) grafted onto carrizo citrange (
C. sinensis L. Osb.
×
Poncirus Trifoliata L. Osb.). The midday stem-water potential and stomatal conductance were measured during the periods considered, and these parameters were used to estimate the plant-water status. Integrated stem-water potential (
Ψ
Int) and integrated stomatal conductance (
g
Int) were calculated for all treatments and used as a water-stress indicator for the crop. Reference equations were formulated to quantify the relations between water-stress indicators (WSR,
Ψ
Int,
g
Int) and the crop response, expressed as yield, yield components, and fruit-quality parameters under limited seasonal water availability. Significant differences in yield were found in the second year of experiment between the stressed treatments and control, although these differences were evident during the first year. The main effects were detected in treatments with a water-sever stress applied during the flowering and fruit-growth phases. When this degree of stress was applied during the maturity phase, it was reflected mainly in fruit-quality parameters (total soluble solids, and titrable acidity). These results lead to the conclusion that, in mature orange trees, deficit irrigation affects yield and fruit quality, while enabling water savings of up to 1000
m
3
ha
−1. Therefore, yield declined on average 10–12% but boosted water productivity 24% with respect to the fully irrigated treatment. Regarding the water-stress indicators used,
Ψ
Int and
g
Int showed highly significant correlations with the yield and fruit-quality parameters.
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