50 research outputs found
Untersuchungen von fotoaktiven Materialien und Strukturen auf Basis von In-S-Verbindungen und siliziumreichen Oxiden
The thesis consists of two parts:
1. The preparation of new materials based on thioindates and indium sulfides with possible photoactive properties. The synthesized materials were tested in the areas of photovoltaics, photocatalysis and/or photoluminescence.
2. The second part of the work deals with the fabrication of multilayers of SRO (Silicon Rich Oxide) with high Si contents and SiO2 prepared by LPCVD (Low Pressure Chemical Vapor Deposition) as well as with studies on their structural, morphologic, optical and luminescent properties.Die Dissertation umfasst zwei Teile:
1. Die Darstellung neuer Materialien auf Basis von Thioindaten und Indiumsulfiden, die photoaktive Eigenschaften aufweisen können. Die hergestellten Materialien wurden auf den Gebieten der Photoelektronik, Photokatalyse und/oder Photolumineszenz getestet.
2. Der zweite Teil der Arbeit beschäftigt sich mit der Darstellung von Multi-Schichten aus SRO (Silicon Rich Oxide) mit hohem Si-Gehalt und SiO2 durch die LPCVD-Methode (Low
Pressure Chemical Vapor Deposition) sowie den Untersuchungen ihrer strukturellen, morphologischen, optischen und lumineszierenden Eigenschaften
Pore size modulation in electrochemically etched macroporous p-type silicon monitored by FFT impedance spectroscopy and Raman scattering
The understanding of the mechanisms of macropore formation in p-type Si with respect to modulation of the pore diameter is still in its infancy. In the present work, macropores with significantly modulated diameters have been produced electrochemically in p-type Si. The effect of the current density and the amount of surfactant in the etching solution are shown to influence the modulation in pore diameter and morphology. Data obtained during the etching process by in situ FFT impedance spectroscopy correlate the pore diameter variation with certain time constants found in the kinetics of the dissolution process. Raman scattering and electron microscopy confirm the mesoscopic structure and roughening of the pore walls. Spectroscopic and microscopic methods confirm that the pore wall morphology is correlated with the conditions of pore modulation
Synthesis and Evaluation of the Fungal Activity of New Pyrazole-Carboxamides against Colletotrichum gloeosporioides
The pyrazole core has been recognized by their biological properties and included in the synthesis of modern agrochemicals. Part of these studies consists of making structural modifications to pesticides for commercial purposes to increase efficacy. In this article, we present the synthesis of four new pyrazol-4-carboxamide 8a-8d derivatives (PCD), through a four-step synthetic protocol, starting with edaravone 1 and primary amines like benzo-fused, aliphatic, and hydrazines, through a process of low environmental impact. Synthesized derivatives were evaluated against one fungal strain of Colletotrichum gloeosporioides BA3, fungus that causes several losses to farmers around the world, through in vitro sensitivity tests. The compound 8c showed better inhibiting behavior against Colletotrichum gloeosporioides BA3, inducing a lag phase of almost 2.77 days. These results were obtained via Gompertz modeling, for the first time reported for biological evaluation of pyrazole-carboxamide derivatives against Colletotrichum gloeosporioides.Fil: Gonzalez Lopez, Edwin Javier. Universidad del Atlántico; Colombia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: León Jaramillo, Jhair Carlhino. Universidad del Atlántico; ColombiaFil: Trilleras Vásquez, Jorge Enrique. Universidad del Atlántico; ColombiaFil: Grande Tovar, Carlos D.. Universidad del Atlántico; ColombiaFil: Peralta Ruiz, Yeimmy. Universidad del Atlántico; Colombia. University Of Teramo. Faculty Of Bioscience And Technology For Food, Agriculture And Environment.; ItaliaFil: Quiroga, Jairo. Universidad del Valle; Colombi
Energy, exergy and economic evaluation comparison of small-scale single and dual pressure organic Rankine cycles integrated with low-grade heat sources
Low-grade heat sources such as solar thermal, geothermal, exhaust gases and industrial waste heat are suitable alternatives for power generation which can be exploited by means of small-scale Organic Rankine Cycle (ORC). This paper combines thermodynamic optimization and economic analysis to assess the performance of single and dual pressure ORC operating with different organic fluids and targeting small-scale applications. Maximum power output is lower than 45 KW while the temperature of the heat source varies in the range 100-200 °C. The studied working fluids, namely R1234yf, R1234ze(E) and R1234ze(Z), are selected based on environmental, safety and thermal performance criteria. Levelized Cost of Electricity (LCOE) and Specific Investment Cost (SIC) for two operation conditions are presented: maximum power output and maximum thermal efficiency. Results showed that R1234ze(Z) achieves the highest net power output (up to 44 kW) when net power output is optimized. Regenerative ORC achieves the highest performance when thermal efficiency is optimized (up to 18%). Simple ORC is the most cost-effective among the studied cycle configurations, requiring a selling price of energy of 0.3 USD/kWh to obtain a payback period of 8 years. According to SIC results, the working fluid R1234ze(Z) exhibits great potential for simple ORC when compared to conventional R245fa
Semiconductor nanostructures for antireflection coatings, transparent contacts, junctionless thermoelectrics and Li-ion batteries
Porous semiconductors structured top-down by electrochemical means, and from bottom-up growth of arrays and arrangements of nanoscale structures, are shown to be amenable to a range of useful thermal, optical, electrical and electrochemical properties. This paper summarises recent investigations of the electrochemical, electrical, optical, thermal and structural properties of porous semiconductors such as Si, In2O3, SnO2 and ITO, and dispersions, arrays and arrangements of nanoscale structures of each of these materials. We summarize the property-inspired application of such structurally engineered arrangements and morphologies of these materials for antireflection coatings, broadband absorbers, transparent contacts to LEDs that improve transmission, electrical contact and external quantum efficiency. Additionally the possibility of thermoelectric performance through structure-mediated variation in thermal resistance and phonon scattering without a p-n junction is shown through phonon engineering in roughened nanowires. Lastly, we show that bulk crystals and nanowires of p- and n-type doped Si are promising for use as anodes in Li-ion batteries
Leukotriene C4 detection as an early graft function marker in liver transplantation
Leukotrienes are a group of compounds belonging to the eicosanoid family that are
formed from the metabolism of arachidonic acid by means of 5-lipoxigenase.
Leukotriene C4 (LTC4) has a pronounced proinflammatory character and is formed by
combining leukotriene A4 with glutation. This step is catalyzed mainly by the
isoenzyme 4-4 of the hepatic glutation transferases, although other enzymes may
participate in its formation. The liver plays a decisive part in the formation of this compound despite the fact that it can be synthesized along other cellular lines. In
orthotopic liver transplant (OLT), the evaluation of the early functioning of the graft is, in many cases, complex. The difficulty of evaluation lies in the absence of specific markers to indicate when the transplanted organ will prove viable notwithstanding
the damage resulting from preservation, and when these lesions are irreversible.
The aim of this study is to determine whether there is a relationship between the
ability to synthesize LTC4 immediately after OLT and the early functioning of the graft
Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences
The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported
by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on
18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based
researchers who signed it in the short time span from 20 September to 6 October 2016
Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study
Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe
Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries
Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely
Hotspots of biogeochemical activity linked to aridity and plant traits across global drylands
14 páginas.- 4 figuras.- 67 referencias.- The online version contains supplementary material available at https://doi.org/10.1038/s41477-024-01670-7Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in drylands, remain virtually unknown. Here we evaluated the relative importance of grazing pressure and herbivore type, climate and plant functional traits on 24 soil physical and chemical attributes that represent proxies of key ecosystem services related to decomposition, soil fertility, and soil and water conservation. To do this, we conducted a standardized global survey of 288 plots at 88 sites in 25 countries worldwide. We show that aridity and plant traits are the major factors associated with the magnitude of plant effects on fertile islands in grazed drylands worldwide. Grazing pressure had little influence on the capacity of plants to support fertile islands. Taller and wider shrubs and grasses supported stronger island effects. Stable and functional soils tended to be linked to species-rich sites with taller plants. Together, our findings dispel the notion that grazing pressure or herbivore type are linked to the formation or intensification of fertile islands in drylands. Rather, our study suggests that changes in aridity, and processes that alter island identity and therefore plant traits, will have marked effects on how perennial plants support and maintain the functioning of drylands in a more arid and grazed world.This research was supported by the European Research Council (ERC grant 647038 (BIODESERT) awarded to F.T.M.) and Generalitat Valenciana (CIDEGENT/2018/041). D.J.E. was supported by the Hermon Slade Foundation (HSF21040). J. Ding was supported by the National Natural Science Foundation of China Project (41991232) and the Fundamental Research Funds for the Central Universities of China. M.D.-B. acknowledges support from TED2021-130908B-C41/AEI/10.13039/501100011033/Unión Europea Next Generation EU/PRTR and the Spanish Ministry of Science and Innovation for the I + D + i project PID2020-115813RA-I00 funded by MCIN/AEI/10.13039/501100011033. O.S. was supported by US National Science Foundation (Grants DEB 1754106, 20-25166), and Y.L.B.-P. by a Marie Sklodowska-Curie Actions Individual Fellowship (MSCA-1018 IF) within the European Program Horizon 2020 (DRYFUN Project 656035). K.G. and N.B. acknowledge support from the German Federal Ministry of Education and Research (BMBF) SPACES projects OPTIMASS (FKZ: 01LL1302A) and ORYCS (FKZ: FKZ01LL1804A). B.B. was supported by the Taylor Family-Asia Foundation Endowed Chair in Ecology and Conservation Biology, and M. Bowker by funding from the School of Forestry, Northern Arizona University. C.B. acknowledges funding from the National Natural Science Foundation of China (41971131). D.B. acknowledges support from the Hungarian Research, Development and Innovation Office (NKFI KKP 144096), and A. Fajardo support from ANID PIA/BASAL FB 210006 and the Millennium Science Initiative Program NCN2021-050. M.F. and H.E. received funding from Ferdowsi University of Mashhad (grant 39843). A.N. and M.K. acknowledge support from FCT (CEECIND/02453/2018/CP1534/CT0001, SFRH/BD/130274/2017, PTDC/ASP-SIL/7743/2020, UIDB/00329/2020), EEA (10/CALL#5), AdaptForGrazing (PRR-C05-i03-I-000035) and LTsER Montado platform (LTER_EU_PT_001) grants. O.V. acknowledges support from the Hungarian Research, Development and Innovation Office (NKFI KKP 144096). L.W. was supported by the US National Science Foundation (EAR 1554894). Y.Z. and X.Z. were supported by the National Natural Science Foundation of China (U2003214). H.S. is supported by a María Zambrano fellowship funded by the Ministry of Universities and European Union-Next Generation plan. The use of any trade, firm or product names does not imply endorsement by any agency, institution or government. Finally, we thank the many people who assisted with field work and the landowners, corporations and national bodies that allowed us access to their land.Peer reviewe