CO2 as feedstock: An air‐ and moisture‐stable iridium(III) catalyst effectively promotes the hydrosilylation of CO2. This reaction leads to silyl formate in a highly selective manner and proceeds ...efficiently under mild conditions, most likely by an outer‐sphere mechanism, as suggested by theoretical calculations.
Remote sensing of solar-induced chlorophyll fluorescence (SIF) is a rapidly advancing front in terrestrial vegetation science, with emerging capability in space-based methodologies and diverse ...application prospects. Although remote sensing of SIF – especially from space – is seen as a contemporary new specialty for terrestrial plants, it is founded upon a multi-decadal history of research, applications, and sensor developments in active and passive sensing of chlorophyll fluorescence. Current technical capabilities allow SIF to be measured across a range of biological, spatial, and temporal scales. As an optical signal, SIF may be assessed remotely using high-resolution spectral sensors in tandem with state-of-the-art algorithms to distinguish the emission from reflected and/or scattered ambient light. Because the red to far-red SIF emission is detectable non-invasively, it may be sampled repeatedly to acquire spatio-temporally explicit information about photosynthetic light responses and steady-state behaviour in vegetation. Progress in this field is accelerating with innovative sensor developments, retrieval methods, and modelling advances. This review distills the historical and current developments spanning the last several decades. It highlights SIF heritage and complementarity within the broader field of fluorescence science, the maturation of physiological and radiative transfer modelling, SIF signal retrieval strategies, techniques for field and airborne sensing, advances in satellite-based systems, and applications of these capabilities in evaluation of photosynthesis and stress effects. Progress, challenges, and future directions are considered for this unique avenue of remote sensing.
•Historical and current progress in remote sensing of SIF are reviewed.•Technical capabilities allow measurements over a range of spatial scales.•Sensor capabilities, retrieval methods, and modelling are now quite advanced.•Applications in vegetation include stress detection and photosynthesis.•Future directions include validation, optimized systems, and interpretation.
Display omitted
•DSP remains a bottleneck in the sustainable and economic production of PHAs.•The selection of DSP should be based on final product specification.•Green solvents have been found to ...dissolve scl and mcl-PHAs.•Chemical-free methods have great potential in large scale recovery of PHAs.
Bioplastics have emerged as a platform to reduce our dependence on fossil fuels. Polyhydroxyalkanoates (PHAs) are a family of biodegradable polyesters with large potential in consumer goods and medical applications. These polymers accumulate in prokaryotic microbes and their recovery is a challenging, often under explored, operation. In the past, oil-derived solvents and chemicals have been widely used as extracting agents, compromising the “environmentally-friendly” claim of bioplastics. Furthermore, the large amount of chemicals and solvents required at the industrial level would negatively impact the economics of the process. The present review presents the latest advances in the field of downstream operations for PHA recovery emphasizing those green technologies with scaling-up feasibility. As for the upstream and fermentation stages, the extraction process needs to be carefully optimized to accomplish a competitive production of PHAs.
•Volatility forecasts are improved by stacking machine learning algorithms.•Merging Artificial Neural Networks with other models increases its forecasting power.•Regardless of the volatility model, ...high volatile regimes lead to higher error rates.•Risk measurements precision is increased by stacking machine learning models.
An appropriate calibration and forecasting of volatility and market risk are some of the main challenges faced by companies that have to manage the uncertainty inherent to their investments or funding operations such as banks, pension funds or insurance companies. This has become even more evident after the 2007–2008 Financial Crisis, when the forecasting models assessing the market risk and volatility failed. Since then, a significant number of theoretical developments and methodologies have appeared to improve the accuracy of the volatility forecasts and market risk assessments. Following this line of thinking, this paper introduces a model based on using a set of Machine Learning techniques, such as Gradient Descent Boosting, Random Forest, Support Vector Machine and Artificial Neural Network, where those algorithms are stacked to predict S&P500 volatility. The results suggest that our construction outperforms other habitual models on the ability to forecast the level of volatility, leading to a more accurate assessment of the market risk.
Since the discovery of charge disproportionation in the FeO2 square-lattice compound Sr3Fe2O7 by Mössbauer spectroscopy more than fifty years ago, the spatial ordering pattern of the ...disproportionated charges has remained "hidden" to conventional diffraction probes, despite numerous x-ray and neutron scattering studies. We have used neutron Larmor diffraction and Fe K-edge resonant x-ray scattering to demonstrate checkerboard charge order in the FeO2 planes that vanishes at a sharp second-order phase transition upon heating above 332 K. Stacking disorder of the checkerboard pattern due to frustrated interlayer interactions broadens the corresponding superstructure reflections and greatly reduces their amplitude, thus explaining the difficulty of detecting them by conventional probes. We discuss the implications of these findings for research on "hidden order" in other materials.
Convalescent plasma is frequently administered to patients with Covid-19 and has been reported, largely on the basis of observational data, to improve clinical outcomes. Minimal data are available ...from adequately powered randomized, controlled trials.
We randomly assigned hospitalized adult patients with severe Covid-19 pneumonia in a 2:1 ratio to receive convalescent plasma or placebo. The primary outcome was the patient's clinical status 30 days after the intervention, as measured on a six-point ordinal scale ranging from total recovery to death.
A total of 228 patients were assigned to receive convalescent plasma and 105 to receive placebo. The median time from the onset of symptoms to enrollment in the trial was 8 days (interquartile range, 5 to 10), and hypoxemia was the most frequent severity criterion for enrollment. The infused convalescent plasma had a median titer of 1:3200 of total SARS-CoV-2 antibodies (interquartile range, 1:800 to 1:3200). No patients were lost to follow-up. At day 30 day, no significant difference was noted between the convalescent plasma group and the placebo group in the distribution of clinical outcomes according to the ordinal scale (odds ratio, 0.83; 95% confidence interval CI, 0.52 to 1.35; P = 0.46). Overall mortality was 10.96% in the convalescent plasma group and 11.43% in the placebo group, for a risk difference of -0.46 percentage points (95% CI, -7.8 to 6.8). Total SARS-CoV-2 antibody titers tended to be higher in the convalescent plasma group at day 2 after the intervention. Adverse events and serious adverse events were similar in the two groups.
No significant differences were observed in clinical status or overall mortality between patients treated with convalescent plasma and those who received placebo. (PlasmAr ClinicalTrials.gov number, NCT04383535.).
ABSTRACT
The increased interest of consumers in probiotic foods requires a deeper knowledge on the possible interactions with drugs, because their pharmacological properties could be modified. In ...this context, these studies are relevant for drugs such as acenocoumarol, whose dosage must be controlled due to, among other factors, food-drug interactions. Acenocoumarol is an oral anticoagulant with a narrow therapeutic range. The aim of the present research is to evaluate, in vitro, the effect of bifidobacteria on acenocoumarol. The drug was incubated with Bifidobacterium bifidum CIDCA 5310 or Bifidobacterium adolescentis CIDCA 5317 in MRS broth at 37°C for 24 h in anaerobic conditions. The effect of incubation with sterilized spent culture supernatants (SSCS) was also evaluated. Analysis by RP-HPLC showed that both bifidobacterial strains reduced the area of the acenocoumarol peak and two new peaks were evidenced. In addition, a decrease in the intensity of the bands at 1650, 1390 and 1110/cm was observed in the FTIR spectroscopic determinations. Moreover, a new band appeared at 1720/cm. No effect on the drug was observed when incubation was performed with SSCS. The present study showed a significant change in the concentration of the anticoagulant after incubation with bifidobacteria and results are compatible with biomodification of the drug due to enzymatic activity of bifidobacteria.
Purpose
To obtain initial data on the effect of different levels of targeted temperature management (TTM) in out-of-hospital cardiac arrest (OHCA).
Methods
We designed a multicentre pilot trial with ...1:1:1 randomization to either 32 °C (
n
= 52), 33 °C (
n
= 49) or 34 °C (
n
= 49), via endovascular cooling devices during a 24-h period in comatose survivors of witnessed OHCA and initial shockable rhythm. The primary endpoint was the percentage of subjects surviving with good neurologic outcome defined by a modified Rankin Scale (mRS) score of ≤ 3, blindly assessed at 90 days.
Results
At baseline, different proportions of patients who had received defibrillation administered by a bystander were assigned to groups of 32 °C (13.5%), 33 °C (34.7%) and 34 °C (28.6%;
p
= 0.03). The percentage of patients with an mRS ≤ 3 at 90 days (primary endpoint) was 65.3, 65.9 and 65.9% in patients assigned to 32, 33 and 34 °C, respectively, non-significant (NS). The multivariate Cox proportional hazards model identified two variables significantly related to the primary outcome: male gender and defibrillation by a bystander. Among the 43 patients who died before 90 days, 28 died following withdrawal of life-sustaining therapy, as follows: 7/16 (43.8%), 10/13 (76.9%) and 11/14 (78.6%) of patients assigned to 32, 33 and 34 °C, respectively (trend test
p
= 0.04). All levels of cooling were well tolerated.
Conclusions
There were no statistically significant differences in neurological outcomes among the different levels of TTM. However, future research should explore the efficacy of TTM at 32 °C.
Clinical trial registration
ClinicalTrials.gov unique identifier: NCT02035839 (
http://clinicaltrials.gov
).
New experimental approaches are required to detect the elusive transient intermediates predicted by simulations of virus assembly or disassembly. Here, an atomic force microscope (AFM) was used to ...mechanically induce partial disassembly of single icosahedral T = 1 capsids and virions of the minute virus of mice. The kinetic intermediates formed were imaged by AFM. The results revealed that induced disassembly of single minute-virus-of-mice particles is frequently initiated by loss of one of the 20 equivalent capsomers (trimers of capsid protein subunits) leading to a stable, nearly complete particle that does not readily lose further capsomers. With lower frequency, a fairly stable, three-fourths-complete capsid lacking one pentamer of capsomers and a free, stable pentamer were obtained. The intermediates most frequently identified (capsids missing one capsomer, capsids missing one pentamer of capsomers, and free pentamers of capsomers) had been predicted in theoretical studies of reversible capsid assembly based on thermodynamic-kinetic models, molecular dynamics, or oligomerization energies. We conclude that mechanical manipulation and imaging of simple virus particles by AFM can be used to experimentally identify kinetic intermediates predicted by simulations of assembly or disassembly.
The world of elite sports has always been characterized by intense competition, where victories are often determined by minimal differences. This means that every little detail in the preparation of ...top-level athletes is crucial to their performance at the highest level. One of the most significant aspects to monitor is the jumping capacity, as it enables the measurement of performance, progression, and helps prevent injuries. Herein, we present the development of a system capable of measuring the flight time and height reached by the user, reporting the results through a smartphone using an Android ad-hoc application, which handles all the data processing. The system consists of an affordable and portable circuit based on an accelerometer. It communicates with the smartphone via UART using a Bluetooth module, and its battery provides approximately 9 h of autonomy, making it suitable for outdoor operations. To evaluate the system's precision, we conducted performance tests (counter-movement jumps) with seven subjects. The results confirmed the system's potential for monitoring high-level sports training sessions, as the average deviation obtained was only 2.1% (~0.01 s) in the analysis of flight time and 4.6% (~0.01 m) in jump height.
PDF
