Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Characterization of InP and InGaN Quantum Dots for Single Photon Sources and AlGaInAs Quantum Dots in Intermediate Band Solar Cells

Die vorliegende Arbeit beschreibt die Charakterisierung von Halbleiter-Quantenpunkten (QP) in unterschiedlichen Materialsystemen. Die hier dargelegten Untersuchungen wurden mit verschiedenen Methoden der optischen Spektroskopie durchgeführt. Zu Beginn der Arbeit werden theoretische Grundlagen von QP hinsichtlich ihrer elektronischen Struktur und statistischen Eigenschaften erläutert. Darüber hinaus wird näher auf die Physik von Solarzellen eingegangen, in dem die relevanten Gleichungen für die Beschreibung des Ladungsträgertransportes hergeleitet und diskutiert werden. Darauf folgend werden die experimentelle Methoden erklärt, welche zur Charakterisierung der jeweiligen Proben dienten. Besonderes Augenmerk wird auf die Methode zur Messung des Zwei-Photonen-Absorptionsprozesses gelegt. Der Abschnitt der experimentell gewonnenen Ergebnisse beginnt mit Untersuchungen an einzelnen, spektral isolierten InP QP, welche mit ultralangsamen Wachstumsraten hergestellt wurden. Aufgrund der sehr geringen Flächendichte konnten grundlegende physikalische Eigenschaften von QP ohne zusätzliche laterale Strukturierungen studiert werden. Mittels Messungen in Abhängigkeit der Anregungsleistung und Detektion in Abhängigkeit der Polarisation konnten die verschiedenen Lumineszenzlinien eines QP-Spektrums den jeweiligen exzitonischen Zuständen zugeordnet werden. Zusätzlich wurden die QP in einem externen Magnetfeld in Faraday-Konfiguration untersucht. Abschließend durchgeführte Autokorrelationsmessungen erlaubten die Untersuchung der zeitlichen Statistik der QP-Photonen. Es konnte die Emission einzelner Photonen nachgewiesen werden. Anschließend folgen spektroskopische Untersuchungen von InP QP, welche mittels sequentiellen Wachstums hergestellt wurden. Anhand von Messungen in Abhängigkeit der Anregungsleistung und bestätigt durch zeitaufgelöste Messungen am QP-Ensemble wurde eine bimodale QP-Verteilung mit Typ-I und Typ-II Bandverlauf bestimmt. Zusätzlich konnten an einzelnen, spektral isolierten QP verschiedene Exziton-Zustände identifiziert werden, bevor abschließend Autokorrelationsmessungen die Emission einzelner Photonen demonstrierten. Zur Steigerung der Auskoppeleffizienz der Photonen wurden InP QP in Mikrosäulenresonatoren, bestehend aus zwei Bragg-Spiegeln mit einer dazwischenliegenden GaInP Kavität, eingebettet. Anfangs wurde die Emission der Kavitätsmode von Strukturen mit unterschiedlichen lateralen Durchmessern charakterisiert. Mittels Temperaturverstimmung konnte die Energie eines einzelnen QP-Exzitons in Resonanz mit der Resonatormode gebracht werden. Im Regime der schwachen Wechselwirkung wurde eine signifikante Überhöhung der Lumineszenzintensität aufgrund des Purcell-Effektes gemessen. Zusätzlich wurde im Regime der schwachen Kopplung die Emission einzelner Photonen anhand von Korrelationsmessungen nachgewiesen. Im zweiten Schritt wurden die QP-Mikrosäulenresonatorstrukturen elektrisch angeregt. Nach einer grundlegenden Charakterisierung konnte auch hier mittels Temperaturverstimmung die Energie der Resonatormode mit der eines Exziton in Resonanz gebracht werden. Im Regime der schwachen Wechselwirkung stieg die Intensität der Lumineszenz aufgrund des Purcell-Effekts signifikant an. Zum Abschluss bestätigen Korrelationsmessungen den Nachweis der Emission einzelner Photonen. In Kapitel 6 werden die Eigenschaften von InGaN QP genauer analysiert. Nitrid-Verbindungshalbleiter kristallieren vorzugsweise stabil in der Wurtzit-Kristallstruktur. Polare Kristallebenen mit fehlender Spiegelsymmetrie führen zu starken piezoelektrischen Feldern. Dies hat eine Lumineszenz mit ausgeprägter linearer Polarisation zur Folge hat. Diese Eigenschaft wurde mittels statistischen Untersuchungen näher betrachtet. Zusätzlich erlaubten Messungen in Abhängigkeit der Anregungsleistung die verschiedenen Exziton-Zustände eines QP zu identifizieren. Zudem wurde die Emission einzelner Photonen durch InGaN QP demonstriert, erstmals sogar bis zu einer Temperatur von 50 K. Im abschliessenden Kapitel wird eine mögliche Anwendung von QP präsentiert, bei der Eigenschaften in Bauteilen gezielt ausgenutzt werden, um die Bandbreite der Photonenabsorption zu erhöhen. Das Konzept der Zwischenband-Solarzellen verspricht auch Photonen mit einer Energie kleiner der Bandlücke des umgebenden Materials aufnehmen zu können und somit den spektralen Absorptionsbereich zu erweitern. Für eine systematische Untersuchung wurden verschiedene Proben mit integrierten AlGaInAs QP hergestellt. Anhand der Strom-Spannungs-Kennlinien der jeweiligen Proben im Dunkeln und unter Beleuchtung konnten wichtige Solarzellenparameter bestimmt werden. Spektrale Messungen liefern Informationen über die externe Quanteneffizienz der Proben. Entscheidend für den experimentellen Nachweis des Funktionsprinzips der Zwischenband-Solarzellen ist die Messung der Zwei-Photonen-Absorption für zwei Photonen mit jeweils kleineren Energien als der Bandlücke des umgebenden Materials.This thesis describes the characterization of semiconductor quantum dots (QDs) in different material systems with potential applications as single photon emitters or intermediate band solar cells. All investigations were carried out by means of optical spectroscopy methods. First, the theoretical background regarding the physics of QDs with respect to their electronic structure and their associated statistical properties are presented. Especially peculiarities of photon statistics of light are explained. Moreover, a closer look at the physics of solar cells and the respective carrier transport is given. Then experimental methods, which were used to characterize the QD-samples, are briefly explained. First, the components and techniques of optical spectroscopy for the study of individual, isolated QDs are described. Second, different experimental technologies for the characterization of solar cells are discussed. The method for measuring the two-photon-absorption process is explained in detail. The section of experimental results begins with studies of individual and spectrally isolated InP QD. Due to the low surface density of one QD per μm2, it is possible to study the physical properties of individual QDs optically without additional lateral sample structuring. Based on power and polarization dependent measurements, various luminescence peaks of a single QD were associated with different exciton states. In addition, the QDs were tested subject to an external magnetic field in a Faraday configuration. Finally, the temporal photon statistics of a single QD was tested using autocorrelation measurement. Afterwards, InP QDs manufactured by cyclic material deposition with growth interruptions were investigated by means of PL spectroscopy. Based on excitation power and time-resolved measurements on the QD ensemble, a bimodal QD distribution of type-I and type-II band alignment was observed. In addition, different exciton states were identified on spectrally isolated single QDs. Finally, the emission of single photons has been demonstrated using autocorrelation measurements. For a more efficient diffraction-limited output coupling of photons, the InP QDs grown by cyclic material deposition were embedded in micropillar resonator structures and investigated by means of spectroscopy. First, structures with different diameters were characterized by photoluminescence spectroscopy. Second, the energy of a single QD exciton and the energy of the cavity were tuned into resonance by changing the temperature. In the regime of weak coupling a luminescence enhancement due to the Purcell Effect was observed. Finally, also in the regime of weak coupling, the emission of single photons has been demonstrated by autocorrelation measurements. In terms of applications, electrical operations are desirable. Therefore, the Bragg mirrors of the micropillar resonator were doped for an efficient current injection and electrical contacts were deposited. After basic electrical characterization, the regime of weak coupling of a single QD exciton and the cavity resulting in a luminescence enhancement were demonstrated by the Purcell effect. Finally, the emission of single photons based on autocorrelation measurements is shown. In this chapter, the luminescence properties of single InGaN QD were investigated. Based on the wurtzite crystal structure of nitrite-compound semiconductors strong piezoelectric fields occur that lead to strongly linearly polarized luminescence. Several QDs were investigated and statistical studies were performed. Excitation power depending measurements allows one to identify the different exciton states of a single QD. In addition, the emission of single photons of InGaN QDs up to a temperature of 50 K was demonstrated for the first time. In the final chapter, an application of QDs in solar cells is presented to specifically exploit the unique properties of QDs in optical devices. The concept of the intermediate band solar cell utilizes the energy position of the QD ground state to absorb photons with energy smaller than the host materials bandgap. This enables an enhancement of the spectral absorption range to longer wavelengths. For systematic studies various samples with AlGaInAs QDs were fabricated. The current voltage characteristics of the samples were tested in the dark and under illumination and the respective solar cell parameters were evaluated. Additionally, based on spectral measurements, the external quantum efficiencies of the samples were determined. Furthermore, the measurement of two sub-bandgap-photon absorption demonstrates the operation principle of an intermediate band solar cell. Finally, band structure calculations are shown, which describe the results qualitatively and which also hint to future sample designs

Single-photon emitters based on epitaxial isolated InP/InGaP quantum dots

Quantum dots as single-photon sources have several advantages, such as emitting light over a broad spectral range and being photostable. Quantum dots with densities as low as 1 dot/mu m(2) have been achieved using ultra-low-rate epitaxy and single-dot emission measured without apertures or post-growth processing. Both excitionic and biexcitonic emissions are observed from single dots created in this way, appearing as doublets with a fine-structure splitting of 320 mu eV. The polarization of the split states is also investigated. Hanbury Brown-Twiss correlation measurements for the excitonic emission under cw excitation show anti-bunching behavior with an autocorrelation value of g((2))(0) = 0.2. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3676273]</p

Site-controlled InP/GaInP quantum dots emitting single photons in the red spectral range

We report on site-controlled growth of InP/GaInP quantum dots (QDs) on GaAs substrates. The QD nucleation sites are defined by shallow nanoholes etched into a GaInP layer. Optimized growth conditions allow us to realize QD arrays with excellent long range ordering on nanohole periods as large as 1.25 mu m. Single QD lines with an average linewidth of 553 mu eV and best values below 200 mu eV are observed. Photoluminescence spectroscopy reveals excitonic and biexcitonic emission in the wavelength range of about 670 nm (1.85 eV) with an exciton-biexciton splitting of 1.8 meV. Second-order photon-autocorrelation measurements show clear single photon emission with g((2))(0) = 0.13 +/- 0.01. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3690872]</p

The mappi?ng and sample model creati?on of sporti?ve recreati?on areas i?n the ci?ty of Düzce

YÖK Tez No: 489808İki büyük metropol olan İstanbul ve Ankara illeri arasında konumlanan ve jeopolitik açıdan büyük öneme sahip olan Düzce ili, her mevsime hitap edebilecek birbirinden farklı doğal kaynaklara sahip olma özelliği ile hem kültür, hem doğa hem de spor turizmine cevap verebilecek potansiyeli olduğu düşünülen bir Batı Karadeniz ilidir. Düzce ilinin zengin doğal kaynaklarından yola çıkılarak kurgulanan tez çalışmasında, ilin sportif rekreasyon alanlarının tespit edilerek haritalandırılması ve ülkemize örnek oluşturabilecek bir doğal yaşam ve spor parkı projesi tasarlanması amaçlanmıştır. Tezin ortaya çıkarılmasında, literatür tarama, doküman analizi, saha analizi, alan araştırması ve projelendirme teknikleri kullanılmıştır.Yapılan tez çalışmasında iki aşamalı sonuç elde edilmiştir. Çalışma ilk aşamasında; ilde doğa, su ve hava sporlarının efektif olarak yapılabileceği varsayımından yola çıkılmış ve bu doğrultuda Düzce ilinde var olan sportif rekreasyon alanlarının tespitine çalışılmıştır. Bu amaçla yapılan alan araştırmaları sonucunda sportif rekreasyon alanlarının aktif kullanım potansiyeli belirlenmiş ve ortaya çıkan eksiklerin giderilmesine yönelik önerilerde bulunulmuştur. Yapılan alan araştırmalarındaki tespitlere dayanılarak doğa sporlarında; doğa yürüyüşü, off-road, avcılık, kuş gözlemciliği, kampçılık, dağcılık, su sporlarında; sportif balıkçılık, rafting, yelken, kano, scuba-diving, hava sporlarında; yamaç paraşütü ve yelken kanat sporlarının verimli şekilde yapılabileceği ortaya çıkmış ve haritalandırılmıştır. İkinci aşamasında ise; konum olarak kritik yere sahip olduğu düşünülen Düzce'nin örnek bir spor şehri olmasına katkı sağlayabilecek bir spor alanı projesi geliştirilmiştir. Efteni gölü üzeri ve çevresine konumlandırılması planlanan doğal yaşam ve spor parkı projesinin; ilin sportif rekreasyon eksiklerinin giderilmesine ve her yaşa hitap edebilecek doğal yaşam alanlarının oluşturulmasına olanak sağlayacağı ön görülmektedir. Sonuç olarak tez çalışması sonunda ortaya çıkan veriler ilgili birimler tarafından değerlendirildiği taktirde; Düzce ili sportif rekreasyon alanlarının ülke turizmine büyük katkı sağlayacağı ve tasarlanan sportif rekreasyon alanı projesi ile Düzce ilinin ülkemizde diğer illere örnek teşkil edebilecek bir spor havzası haline dönüşeceği düşünülmektedir.Located between the provinces of Istanbul and Ankara which are being two major metropolis and having a great importance in aspect of geopolitics, the province of Duzce is a western Black Sea Region province that is being thought of having adequate potential to both culture and nature and also to the sports tourism with the different characteristics from each other that can cater for all seasons. By setting off from the rich natural resources of the province of Duzce, it is aimed mapping of sportive recreation areas of the province by detecting and planning of natural life and sports park project that can be a sample to our country. In the creation of the thesis, the technic of literature review, document analysis, site analysis, field analaysis and design techniques are used. In the thesis study which is done, it is obtained two phased result. In the first phase of the study, it is set off from the hypothesis of nature, water and air sports can be done effectively in the province and in this way, it is tried to detect the sportive recreational fields that exist in the province of Duzce. As a result of the field studies made with this aim, the active usage potantial of sportive recreational fields is detected and suggestions made according to resolve the deficiencies that come out. Based on the findings made in the field researches in nature sports; hiking, off-roading, hunting, bird watching, camping, mountaineering, in the water sports; sportive fishing, rafting, sailing, canoe, scuba diving, in the air sports; paragliding and sailing, wing sports can be done effectively that came out and being mapped. In the second phase a sports field project is developed that can make a contribution to be a sample sports city of Duzce that is thought to have a critic location. The project of natural life and sports park which is thought to locate on and the surroundings of the Lake Efteni is foreseen to eliminate the deficiencies of sportive recreation of the province and to allow forming of natural life areas that can cater for all ages. As a result of the study it is believed that if the results of this study are evaluated by related institutions sportive recreation areas of the city of Düzce will dramatically contribute to the tourism of our country and designed sportive recreation area projects may transform Düzce into asports baslin which may be a good example for other cities

Single photon emission from InGaN/GaN quantum dots up to 50 K

We have investigated the optical properties of single InGaN quantum dots (QDs) by means of microphotoluminescence (mu PL) spectroscopy. The QDs were grown on sapphire substrate using metal organic vapor phase epitaxy. Sharp and isolated single exciton emission lines in the blue spectral range were observed. The QD luminescence shows a strong degree of linear polarization up to 96% perpendicular to the growth axis (c-axis) with no preferential alignment in the xy plane. Second order autocorrelation measurements were performed under pulsed excitation and single photon emission up to 50 K is demonstrated. (C) 2012 American Institute of Physics. [doi:10.1063/1.3683521]</p

Radar-based monitoring of glass fiber reinforced composites during fatigue testing

This work aims at radar sensors in the frequency band from 57 to 64 GHz that can be embedded in wind turbine blades during manufacturing, enabling non-destructive quality inspection directly after production and structural health monitoring (SHM) during the complete service life of the blade. In this paper, we show the fundamental damage detection capability of this sensor technology during fatigue testing of typical rotor blade materials. Therefore, a frequency modulated continuous wave (FMCW) radar sensor is used for damage diagnostics, and the results are validated by simultaneous camera recordings. Here, we focus on the failure modes delamination, fiber waviness (ondulation), and inter-fiber failure. For each failure mode, three samples have been designed and experimentally investigated during fatigue testing. A damage index has been proposed based on residual, that is, differential, signals exploiting measurements from pristine structural conditions. This study shows that the proposed innovative radar approach is able to detect continuous structural degradation for all failure modes by means of gradual signal changes

Relationship between the level of KdpFABC at steady state and the initial external K⁺ concentration.

<p>Cells were grown in minimal medium containing 10⁺, then shifted in the mid-logarithmic growth phase to the indicated external K⁺ concentrations (40 µM–5.0 mM K⁺), and after 3 h of aerobic incubation at 37°C, cells were harvested, and the level of KdpFABC was determined by quantitative Western blot analysis (•). The red trace depicts the relationship predicted by the model.</p

Optimized parameters of the mathematical Kdp model.

<p>The experimental data for the wild type, the RH010 mutant and the RH010/pKT84 mutant cannot be reproduced using a single set of parameters. The Table lists the values of each parameter used to describe the dynamics of each strain.</p

Predicted time-courses of intracellular variables of the Kdp system derived from simulations based on the model for different levels of K⁺ availability.

<p>K⁺ availability is determined by the initial concentration of external K⁺ at t = 0 h, <i>K⁺_ex</i>(0). <i>kdpFABC</i> transcripts and KdpFABC complexes decrease with increasing <i>K⁺_ex</i> levels (<b>A, B</b>). Intracellular K⁺ (free and bound) increases with increasing external K⁺ (<b>C, D</b>). Time-courses of phosphorylated KdpD and KdpE are qualitatively very similar to the <i>kdpFABC</i> curves (<b>E, F</b>).</p