Thermo-mechanochemistry applied on heterogeneous catalyst preparation for CO oxidation and COPrOx reactions

L'objectiu d'aquest projecte final de màster va ser estudiar els impactes adversos de la termo-mecanoquímica aplicada en la preparació de catalitzadors heterogenis per a les reaccions d'oxidació de CO i COPrOx. El procés es va dur a terme en fase gas utilitzant un reactor tubular, on es van analitzar les corbes de conversió i selectivitat de totes dues reaccions. Per monitorar els gasos de sortida del reactor, es va utilitzar l'anàlisi de cromatografia de gasos amb argó com a gas portador inert. Es van realitzar diferents processos de síntesi mecanoquímica del catalitzador, variant la temperatura i el temps de durada del procés de síntesi del Au/CeO_2. Aquests canvis de temperatura es van aconseguir mitjançant l'addició d'energia externa en forma de calor. En el laboratori, es va dissenyar i implementar el sistema de reacció experimental, es va preparar el catalitzador de Au/CeO_2 utilitzant la tècnica mecanoquímica amb un molí de boles, es van realitzar els experiments i es van caracteritzar les mostres. A més, es va dur a terme un estudi econòmic i una breu avaluació de l'impacte mediambiental. L'eficiència de les mostres es va comparar en funció de dos paràmetres principals: la temperatura i el temps de durada de la síntesi mecanoquímica del Au/CeO_2. Els millors resultats es van obtenir en l'oxidació de CO amb la síntesi del catalitzador a temperatura ambient, mentre que en COPrOx es van aconseguir resultats òptims utilitzant mostres escalfades a 50ºC i posteriorment refredades. Aquests troballes destaquen la importància de controlar amb cura els paràmetres de síntesi per a maximitzar l'eficiència dels catalitzadors heterogenis en totes dues reaccions.El objetivo de este proyecto final de máster fue estudiar los impactos adversos de la termo-mecanoquímica aplicada en la preparación de catalizadores heterogéneos para las reacciones de oxidación de CO y COPrOx. El proceso se llevó a cabo en fase gas utilizando un reactor tubular, donde se analizaron las curvas de conversión y selectividad de ambas reacciones. Para monitorear los gases de salida del reactor, se utilizó análisis de cromatografía de gases con argón como gas portador inerte. Se llevaron a cabo diferentes procesos de síntesis del catalizador, variando la temperatura y el tiempo de duración del proceso de síntesis mecanoquímica del Au/CeO_2. Estos cambios de temperatura se lograron mediante la adición de energía externa en forma de calor. En el laboratorio, se diseñó e implementó el sistema de reacción experimental, se preparó el catalizador de Au/CeO_2 utilizando la técnica mecanoquímica con un molino de bolas, se realizaron los experimentos y se caracterizaron las muestras. Además, se llevó a cabo un estudio económico y una breve evaluación del impacto medioambiental. La eficiencia de las muestras se comparó en función de dos parámetros principales: la temperatura y el tiempo de duración de la síntesis mecanoquímica del Au/CeO_2. Los mejores resultados se obtuvieron en la oxidación de CO con la síntesis del catalizador a temperatura ambiente, mientras que en COPrOx se lograron resultados óptimos utilizando muestras calentadas a 50ºC y posteriormente enfriadas. Estos hallazgos resaltan la importancia de controlar cuidadosamente los parámetros de síntesis para maximizar la eficiencia de los catalizadores heterogéneos en ambas reacciones.The objective of this final master's project was to study the adverse impacts of thermo-mechanochemistry applied in the preparation of heterogeneous catalysts for CO oxidation and COPrOx reactions. The process was carried out in the gas phase using a tubular reactor, where the conversion and selectivity curves of both reactions were analyzed. Gas emissions from the reactor were monitored using gas chromatography analysis with argon as an inert carrier gas. Different mechanochemical catalyst synthesis processes were performed, varying the temperature and duration of the Au/CeO_2 catalyst synthesis process. These temperature changes were achieved by adding external energy in the form of heat. In the laboratory, the experimental reaction system was designed and implemented, the Au/CeO_2 catalyst was prepared using the mechanochemical technique with a ball mill, experiments were conducted, and the samples were characterized. Additionally, an economic study and a brief assessment of the environmental impact were carried out. The efficiency of the samples was compared based on two main parameters: the temperature and duration of the Au/CeO_2 mechanochemical synthesis. The best results were obtained in the CO oxidation with catalyst synthesis at room temperature, while in COPrOx, optimal results were achieved using samples heated to 50ºC and subsequently cooled. These findings highlight the importance of carefully controlling the synthesis parameters to maximize the efficiency of heterogeneous catalysts in both reactions

First results from an experiment excluding three sizes classes of herbivores from tundra vegetation in southern Yamal, Russia

Plant-herbivore relationships are important for the functioning of tundra ecosystems. Here, we report the first results from an exclosure experiment that, something very few studies have done, separated the impact of three sizes of herbivores (small, medium and large) on nine functional groups of plants in the low arctic tundra of the Yamal Peninsula (Russia). Herbivore faeces counts in the exclosures and pictures from automatic cameras proved that the experimental setup worked. The majority of plant groups did not respond to exclusion of herbivores, supporting our expectation that vegetation responses in tundra are generally too slow to be measured during one growing season. The plant groups with highest growth rates and palatability (forbs and grasses) increased their biomass in meadows associated to tall willow shrubs when reindeer were excluded. This result was expected based on studies from other arctic regions. Our results also suggested that willow meadows and forb tundra, which are focal habitat for herbivores, are resilient and have the capacity to increase their biomass over a short term. We expect this experiment to provide valuable information on how different plant functional types and habitats with different growing conditions and importance to herbivores respond to relaxed grazing pressure from a variety of tundra herbivores

Reduction of CPR artifacts in the ventricular fibrillation ECG by coherent line removal

<p>Abstract</p> <p>Background</p> <p>Interruption of cardiopulmonary resuscitation (CPR) impairs the perfusion of the fibrillating heart, worsening the chance for successful defibrillation. Therefore ECG-analysis <it>during ongoing chest compression </it>could provide a considerable progress in comparison with standard analysis techniques working only during "hands-off" intervals.</p> <p>Methods</p> <p>For the reduction of CPR-related artifacts in ventricular fibrillation ECG we use a localized version of the <it>coherent line removal </it>algorithm developed by Sintes and Schutz. This method can be used for removal of periodic signals with sufficiently coupled harmonics, and can be adapted to specific situations by optimal choice of its parameters (e.g., the number of harmonics considered for analysis and reconstruction). Our testing was done with 14 different human ventricular fibrillation (VF) ECGs, whose fibrillation band lies in a frequency range of [1 Hz, 5 Hz]. The VF-ECGs were mixed with 12 different ECG-CPR-artifacts recorded in an animal experiment during asystole. The length of each of the ECG-data was chosen to be 20 sec, and testing was done for all 168 = 14 × 12 pairs of data. VF-to-CPR ratio was chosen as -20 dB, -15 dB, -10 dB, -5 dB, 0 dB, 5 dB and 10 dB. Here -20 dB corresponds to the highest level of CPR-artifacts.</p> <p>Results</p> <p>For non-optimized <it>coherent line removal </it>based on signals with a VF-to-CPR ratio of -20 dB, -15 dB, -10 dB, -5 dB and 0 dB, the signal-to-noise gains (SNR-gains) were 9.3 ± 2.4 dB, 9.4 ± 2.4 dB, 9.5 ± 2.5 dB, 9.3 ± 2.5 dB and 8.0 ± 2.7 (mean ± std, <it>n </it>= 168), respectively. Characteristically, an original VF-to-CPR ratio of -10 dB, corresponds to a variance ratio <it>var</it>(VF):<it>var</it>(CPR) = 1:10. An improvement by 9.5 dB results in a restored VF-to-CPR ratio of -0.5 dB, corresponding to a variance ratio <it>var</it>(VF):<it>var</it>(CPR) = 1:1.1, the variance of the CPR in the signal being reduced by a factor of 8.9.</p> <p>Discussion</p> <p>The <it>localized coherent line removal </it>algorithm uses the information of a single ECG channel. In contrast to multi-channel algorithms, no additional information such as thorax impedance, blood pressure, or pressure exerted on the sternum during CPR is required. Predictors of defibrillation success such as mean and median frequency of VF-ECGs containing CPR-artifacts are prone to being governed by the harmonics of the artifacts. Reduction of CPR-artifacts is therefore necessary for determining reliable values for estimators of defibrillation success.</p> <p>Conclusions</p> <p>The <it>localized coherent line removal </it>algorithm reduces CPR-artifacts in VF-ECG, but does not eliminate them. Our SNR-improvements are in the same range as offered by multichannel methods of Rheinberger et al., Husoy et al. and Aase et al. The latter two authors dealt with different ventricular rhythms (VF and VT), whereas here we dealt with VF, only. Additional developments are necessary before the algorithm can be tested in real CPR situations.</p

Hiding in the background: community-level patterns in invertebrate herbivory across the tundra biome

Invertebrate herbivores depend on external temperature for growth and metabolism. Continued warming in tundra ecosystems is proposed to result in increased invertebrate herbivory. However, empirical data about how current levels of invertebrate herbivory vary across the Arctic is limited and generally restricted to a single host plant or a small group of species, so predicting future change remains challenging. We investigated large-scale patterns of invertebrate herbivory across the tundra biome at the community level and explored how these patterns are related to long-term climatic conditions and year-of-sampling weather, habitat characteristics, and aboveground biomass production. Utilizing a standardized protocol, we collected samples from 92 plots nested within 20 tundra sites during summer 2015. We estimated the community-weighted biomass lost based on the total leaf area consumed by invertebrates for the most common plant species within each plot. Overall, invertebrate herbivory was prevalent at low intensities across the tundra, with estimates averaging 0.94% and ranging between 0.02 and 5.69% of plant biomass. Our results suggest that mid-summer temperature influences the intensity of invertebrate herbivory at the community level, consistent with the hypothesis that climate warming should increase plant losses to invertebrates in the tundra. However, most of the observed variation in herbivory was associated with other site level characteristics, indicating that other local ecological factors also play an important role. More details about the local drivers of invertebrate herbivory are necessary to predict the consequences for rapidly changing tundra ecosystems.KeywordsBackground herbivory Biomass loss Climate change Community-weighted average Invertebrate Insects Tundra </div

EuReCa ONE—27 Nations, ONE Europe, ONE Registry A prospective one month analysis of out-of-hospital cardiac arrest outcomes in 27 countries in Europe

AbstractIntroductionThe aim of the EuReCa ONE study was to determine the incidence, process, and outcome for out of hospital cardiac arrest (OHCA) throughout Europe.MethodsThis was an international, prospective, multi-centre one-month study. Patients who suffered an OHCA during October 2014 who were attended and/or treated by an Emergency Medical Service (EMS) were eligible for inclusion in the study. Data were extracted from national, regional or local registries.ResultsData on 10,682 confirmed OHCAs from 248 regions in 27 countries, covering an estimated population of 174 million. In 7146 (66%) cases, CPR was started by a bystander or by the EMS. The incidence of CPR attempts ranged from 19.0 to 104.0 per 100,000 population per year. 1735 had ROSC on arrival at hospital (25.2%), Overall, 662/6414 (10.3%) in all cases with CPR attempted survived for at least 30 days or to hospital discharge.ConclusionThe results of EuReCa ONE highlight that OHCA is still a major public health problem accounting for a substantial number of deaths in Europe.EuReCa ONE very clearly demonstrates marked differences in the processes for data collection and reported outcomes following OHCA all over Europe. Using these data and analyses, different countries, regions, systems, and concepts can benchmark themselves and may learn from each other to further improve survival following one of our major health care events

The impact of different size herbivores on plant biomass in Yamal (Russia)

Tundra ecosystems are changing environments that are greatly affected by plant-herbivore relationships. Many herbivores of different sizes eat, trample or clip plants. However they can also act as support through nutrient addition by faeces. In this study I look at the impact of three sizes of herbivores (large, medium and small) on ten functional groups of plants (nitrogen-fixing forbs, erect willows, birch bushes, evergreen ericoids, nitrogen-non-fixing forbs, grasses, sedges, deciduous shrubs, semi-evergreen shrubs and toxic plants) in three habitats of differing productivity and importance for herbivores on the Yamal Peninsula in Russia. My research question is: “is the impact of herbivores cumulative on palatable plants and complementary on less palatable plants?”. To answer this question, I investigated the first year data from an exclosure experiment that was set up in 2014. There were tendencies suggesting that herbivores do not always have a cumulative impact on palatable plants and that the impact on less palatable plants is not always complementary. However, based on plant traits, herbivores’ preferences and previous studies I conclude that the fastest growing plants usually show responses already after a very short time of herbivore exclusion. Further research during the next years will shed light on persistence of these results