10 research outputs found
Mémoires sur la famille des Graminées : contenant, 1\ub0. La physiologie; 2\ub0. La classification des Graminées; 3\ub0. L\u27analyse microscopique et le développement de la fécule dans les céréales /
High-Throughput Synthesis and Characterization of Eu Doped Ba<sub><i>x</i></sub>Sr<sub>2–<i>x</i></sub>SiO<sub>4</sub> Thin Film Phosphors
High-throughput
techniques have been employed for the synthesis
and characterization of thin film phosphors of Eu-doped Ba<sub><i>x</i></sub>Sr<sub>2–<i>x</i></sub>SiO<sub>4</sub>. Direct synthesis from evaporation of the constituent elements under
a flux of atomic oxygen on a sapphire substrate at 850 °C was
used to directly produce thin film libraries (415 nm thickness) of
the crystalline orthosilicate phase with the desired compositional
variation (0.24 > <i>x</i> > 1.86). The orthosilicate
phase
could be synthesized as a pure, or predominantly pure, phase. Annealing
the as synthesized library in a reducing atmosphere resulted in the
reduction of the Eu while retaining the orthosilicate phase, and resulted
in a materials thin film library where fluorescence excited by blue
light (450 nm) was observable by the naked eye. Parallel screening
of the fluorescence from the combinatorial libraries of Eu doped Ba<sub><i>x</i></sub>Sr<sub>2–<i>x</i></sub>SiO<sub>4</sub> has been implemented by imaging the fluorescent radiation
over the library using a monochrome digital camera using a series
of color filters. Informatics tools have been developed to allow the
1931 CIE color coordinates and the relative quantum efficiencies of
the materials library to be rapidly assessed and mapped against composition,
crystal structure and phase purity. The range of compositions gave
values of CIE<i><sub>x</sub></i> between 0.17 and 0.52 and
CIE<i><sub>y</sub></i> between 0.48 and 0.69 with relative
efficiencies in the range 2.0 × 10<sup>–4</sup>–7.6
× 10<sup>–4</sup>. Good agreement was obtained between
the thin film phosphors and the fluorescence characteristics of a
number of corresponding bulk phosphor powders. The thermal quenching
of fluorescence in the thin film libraries was also measured in the
temperature range 25–130 °C: The phase purity of the thin
film was found to significantly influence both the relative quantum
efficiency and the thermal quenching of the fluorescence
Phthalocyanine–Peptide Conjugates: Receptor-Targeting Bifunctional Agents for Imaging and Photodynamic Therapy
The synthesis of a series of new zinc phthalocyanine–peptide
conjugates targeting the gastrin-releasing peptide (GRP) and integrin
receptors is reported. Two alternative synthetic methods based on
Sonogashira cross-coupling of an iodinated zinc phthalocyanine with
acetylenic bombesin or arginine–glycine–aspartic acid
(RGD) derivatives, either in solution or on solid phase, are presented.
The water-soluble conjugates were screened for their photodynamic
efficacy against several cancer cell lines expressing different levels
of GRP and integrin receptors, and their intracellular localization
was evaluated via confocal fluorescence microscopy. Variations in
photocytotoxicity between the conjugates correlate to differences
in hydrophobicity as well as receptor-mediated cell uptake. In the
case of the phthalocyanine–bombesin conjugate, competition
experiments confirm the involvement of the GRP receptor in both the
phototherapeutic activity as well as intracellular localization. These
findings warrant further in vivo studies to evaluate the potential
of this conjugate as photosensitizer for photodynamic therapy (PDT)
of cancers overexpressing the GRP receptor
<sup>68</sup>Ga/DOTA- and <sup>64</sup>Cu/NOTA-Phthalocyanine Conjugates as Fluorescent/PET Bimodal Imaging Probes
In this paper, we describe the synthesis
and characterization of
a series of new bimodal probes combining water-soluble sulfonated
zinc phthalocyanine (ZnPc) as a fluorescence imaging unit and either <sup>68</sup>Ga/1,4,7,10-tetraazocyclododecane-<i>N</i>,<i>N</i>′<i>N</i>″,<i>N</i>′″-tetraacetic
acid (DOTA) or <sup>64</sup>Cu/1,4,7-triazacyclononane-1,4,7-triacetic
acid (NOTA) for PET imaging. The two moieties were linked through
aliphatic chains of different lengths to modulate amphiphilicity.
Labeling of DOTA– or NOTA–ZnPc conjugates with <sup>68</sup>Ga (<i>t</i><sub>1/2</sub> = 68 min) and <sup>64</sup>Cu (<i>t</i><sub>1/2</sub> = 12.7 h) was performed at 100
°C for 15 min with >90% efficiency for all conjugates. <i>In vitro</i> plasma stability assays demonstrated high stability
of the <sup>64</sup>Cu/NOTA-ZnPc conjugate, which remained intact
over a 24 h time period, and reasonably high stability of the <sup>68</sup>Ga/DOTA-ZnPc conjugate, which released up to 7% of free <sup>68</sup>Ga over a 3 h period. Based on <i>in vitro</i> plasma
stability results, we performed biodistribution studies on two <sup>64</sup>Cu-labeled derivatives, which allowed us to select a single
candidate for preliminary <i>in vivo</i> experiments. Fluorescence
and PET imaging confirmed the potential of these novel conjugates
to act as bimodal probes
A prospective international observational prevalence study on prone positioning of ARDS patients: the APRONET (ARDS Prone Position Network) study
While prone positioning (PP) has been shown to improve patient survival in moderate to severe acute respiratory distress syndrome (ARDS) patients, the rate of application of PP in clinical practice still appears low. This study aimed to determine the prevalence of use of PP in ARDS patients (primary endpoint), the physiological effects of PP, and the reasons for not using it (secondary endpoints). The APRONET study was a prospective international 1-day prevalence study performed four times in April, July, and October 2016 and January 2017. On each study day, investigators in each ICU had to screen every patient. For patients with ARDS, use of PP, gas exchange, ventilator settings and plateau pressure (Pplat) were recorded before and at the end of the PP session. Complications of PP and reasons for not using PP were also documented. Values are presented as median (1st-3rd quartiles). Over the study period, 6723 patients were screened in 141 ICUs from 20 countries (77% of the ICUs were European), of whom 735 had ARDS and were analyzed. Overall 101 ARDS patients had at least one session of PP (13.7%), with no differences among the 4 study days. The rate of PP use was 5.9% (11/187), 10.3% (41/399) and 32.9% (49/149) in mild, moderate and severe ARDS, respectively (P = 0.0001). The duration of the first PP session was 18 (16-23) hours. Measured with the patient in the supine position before and at the end of the first PP session, PaO2/FIO2 increased from 101 (76-136) to 171 (118-220) mmHg (P = 0.0001) driving pressure decreased from 14 [11-17] to 13 [10-16] cmH2O (P = 0.001), and Pplat decreased from 26 [23-29] to 25 [23-28] cmH2O (P = 0.04). The most prevalent reason for not using PP (64.3%) was that hypoxemia was not considered sufficiently severe. Complications were reported in 12 patients (11.9%) in whom PP was used (pressure sores in five, hypoxemia in two, endotracheal tube-related in two ocular in two, and a transient increase in intracranial pressure in one). In conclusion, this prospective international prevalence study found that PP was used in 32.9% of patients with severe ARDS, and was associated with low complication rates, significant increase in oxygenation and a significant decrease in driving pressur
Water-Dispersible Sugar-Coated Iron Oxide Nanoparticles. An Evaluation of their Relaxometric and Magnetic Hyperthermia Properties
Synthesis of functionalized magnetic nanoparticles (NPs) for biomedical applications represents a current challenge. In this paper we present the synthesis and characterization of water-dispersible sugar-coated iron oxide NPs specifically designed as magnetic fluid hyperthermia heat mediators and negative contrast agents for magnetic resonance imaging. In particular, the influence of the inorganic core size was investigated. To this end, iron oxide NPs with average size in the range of 4-35 nm were prepared by thermal decomposition of molecular precursors and then coated with organic ligands bearing a phosphonate group on one side and rhamnose, mannose, or ribose moieties on the other side. In this way a strong anchorage of the organic ligand on the inorganic surface was simply realized by ligand exchange, due to covalent bonding between the Fe3+ atom and the phosphonate group. These synthesized nanoobjects can be fully dispersed in water forming colloids that are stable over very long periods. Mannose, ribose, and rhamnose were chosen to test the versatility of the method and also because these carbohydrates, in particular rhamnose, which is a substrate of skin lectin, confer targeting properties to the nanosystems. The magnetic, hyperthermal, and relaxometric properties of all the synthesized samples were investigated. Iron oxide NPs of ca. 16-18 nm were found to represent an efficient bifunctional targeting system for theranostic applications, as they have very good transverse relaxivity (three times larger than the best currently available commercial products) and large heat release upon application of radio frequency (RF) electromagnetic radiation with amplitude and frequency close to the human tolerance limit. The results have been rationalized on the basis of the magnetic properties of the investigated samples
Outcomes of Patients Presenting with Mild Acute Respiratory Distress Syndrome: Insights from the LUNG SAFE Study
WHAT WE ALREADY KNOW ABOUT THIS TOPIC: Hospital mortality in acute respiratory distress syndrome is approximately 40%, but mortality and trajectory in "mild" acute respiratory distress syndrome (classified only since 2012) are unknown, and many cases are not detected WHAT THIS ARTICLE TELLS US THAT IS NEW: Approximately 80% of cases of mild acute respiratory distress syndrome persist or worsen in the first week; in all cases, the mortality is substantial (30%) and is higher (37%) in those in whom the acute respiratory distress syndrome progresses BACKGROUND:: Patients with initial mild acute respiratory distress syndrome are often underrecognized and mistakenly considered to have low disease severity and favorable outcomes. They represent a relatively poorly characterized population that was only classified as having acute respiratory distress syndrome in the most recent definition. Our primary objective was to describe the natural course and the factors associated with worsening and mortality in this population. METHODS: This study analyzed patients from the international prospective Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) who had initial mild acute respiratory distress syndrome in the first day of inclusion. This study defined three groups based on the evolution of severity in the first week: "worsening" if moderate or severe acute respiratory distress syndrome criteria were met, "persisting" if mild acute respiratory distress syndrome criteria were the most severe category, and "improving" if patients did not fulfill acute respiratory distress syndrome criteria any more from day 2. RESULTS: Among 580 patients with initial mild acute respiratory distress syndrome, 18% (103 of 580) continuously improved, 36% (210 of 580) had persisting mild acute respiratory distress syndrome, and 46% (267 of 580) worsened in the first week after acute respiratory distress syndrome onset. Global in-hospital mortality was 30% (172 of 576; specifically 10% [10 of 101], 30% [63 of 210], and 37% [99 of 265] for patients with improving, persisting, and worsening acute respiratory distress syndrome, respectively), and the median (interquartile range) duration of mechanical ventilation was 7 (4, 14) days (specifically 3 [2, 5], 7 [4, 14], and 11 [6, 18] days for patients with improving, persisting, and worsening acute respiratory distress syndrome, respectively). Admissions for trauma or pneumonia, higher nonpulmonary sequential organ failure assessment score, lower partial pressure of alveolar oxygen/fraction of inspired oxygen, and higher peak inspiratory pressure were independently associated with worsening. CONCLUSIONS: Most patients with initial mild acute respiratory distress syndrome continue to fulfill acute respiratory distress syndrome criteria in the first week, and nearly half worsen in severity. Their mortality is high, particularly in patients with worsening acute respiratory distress syndrome, emphasizing the need for close attention to this patient population