Ligand exchange reactions of 1.5-nm triphenylphosphine-stabilized nanoparticles with ω-functionalized thiols provides a versatile approach to functionalized, 1.5-nm gold nanoparticles from a single ...precursor. We describe the broad scope of this method and the first mechanistic investigation of thiol-for-phosphine ligand exchanges. The method is convenient and practical and tolerates a surprisingly wide variety of technologically important functional groups while producing very stable nanoparticles that essentially preserve the small core size and size dispersity of the precursor particle. The mechanistic studies reveal a novel three-stage mechanism that can be used to control the extent of ligand exchange. During the first stage of the exchange, AuCl(PPh3) is liberated, followed by replacement of the remaining phosphine ligands as PPh3 (assisted by gold complexes in solution). The final stage involves completion and reorganization of the thiol-based ligand shell.
Purification and size-based separation of nanoparticles remain significant challenges in the preparation of well-defined materials for fundamental studies and applications. Diafiltration shows ...considerable potential for the efficient and convenient purification and size separation of water-soluble nanoparticles, allowing for the removal of small-molecule impurities and for the isolation of small nanoparticles from larger nanostructures in a single process. Herein, we report studies aimed at assessing the suitability of diafiltration for (i) the purification of water-soluble thiol-stabilized 3-nm gold nanoparticles, (ii) the separation of a bimodal distribution of nanoparticles into the corresponding fractions, and (iii) the separation of a polydisperse sample into fractions of differing mean core diameter. NMR, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) measurements demonstrate that diafiltration produces nanoparticles with a much higher degree of purity than is possible by dialysis or a combination of solvent washes, chromatography, and ultracentrifugation. UV−visible spectroscopic and transmission electron microscopic (TEM) analyses show that diafiltration offers the ability to separate nanoparticles of disparate core size. These results demonstrate the applicability of diafiltration for the rapid and green preparation of high-purity gold nanoparticle samples and the size separation of heterogeneous nanoparticle samples. They also suggest the development of novel diafiltration membranes specifically suited to high-resolution nanoparticle size separation.
Schlafstörungen weisen eine zunehmende Prävalenz auf. Im Bereich der respiratorischen Schlafmedizin ist die obstruktive Schlafapnoe (OSA) die häufigste organisch bedingte Schlafstörung. Die ...nächtliche Überdrucktherapie („positive airway pressure PAP therapy“) stellt die Standardtherapie dar; die Unterkieferprotrusionsschiene (UKPS) wird seit Kurzem als Zweitlinientherapie seitens der gesetzlichen Krankenversicherung finanziert. Positive Effekte auf Symptomatik und Folgeerkrankungen sind, jedoch nur bei regelmäßiger und langfristiger Therapienutzung, zu erwarten. Aufgrund der steigenden Prävalenzzahlen zeigen sich in der bestehenden intersektoralen Versorgung Schnittstellenprobleme, die zu Fehlversorgungen und langen Wartezeiten im Diagnostik- und Therapiepfad führen. Dies wirkt sich in der Therapienachsorge auch auf die Therapieadhärenz aus. Neuartige Methoden aus dem Bereich E‑ und M‑Health bieten bereits heutzutage smarte Lösungen für aktuell noch unzureichend adressierte Probleme in der Schlafmedizin an. Neue Sensorik und Applikationen für digitale Endgeräte (Apps) eröffnen Möglichkeiten für ein breites Screening auf die Volkserkrankung Schlafapnoe. Cloud-basierte Telemedizinkonzepte können helfen, betroffene Patienten im Rahmen der etablierten Stufendiagnostik frühzeitig und bedarfsgerecht einer schlafmedizinischen Expertise zuzuführen und die interdisziplinäre Kommunikation zu verbessern. Telemonitoring kann zudem genutzt werden, um Patienten mit Therapieproblemen frühzeitig zu identifizieren. So können Therapieabbruchraten reduziert bzw. frühzeitig Patienten für alternative Therapien identifiziert werden. Letztlich werden sich all diese Methoden nur dann durchsetzen und Patienten zugutekommen, wenn sie Schlafmediziner in ihrer alltäglichen Arbeit unterstützen und entlasten sowie sinnvoll in bestehende Versorgungsprozesse und deren Vergütung eingebunden werden.
Digitalisierung/E-Health Schöbel, C.; Woehrle, H.
Somnologie : Schlafforschung und Schlafmedizin = Somnology : sleep research and sleep medicine,
09/2020, Letnik:
24, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Auch muss klar darauf hingewiesen werden, dass hierdurch die Ausbildung nicht vereinfacht werden kann, da das Rückfallsystem eines jeden automatisierten Systems der voll ausgebildete Arzt ist. Um aus ...diesen „Big Data“ für uns verständliche Aussagen zu generieren, bedarf es zusätzlich weiterer neuartiger Methoden aus dem Bereich der Data Science. Gerade im Bereich der digitalen Medizin, oft E‑Health genannt, sind gesetzlich regulierende Komponenten von eminenter Bedeutung: Neben dem Medizinproduktegesetz (MPG), das im Jahr 2021 von der EU-weit geltenden Medical Device Regulation (MDR) als Grundlage für die Zertifizierung medizinischer Produkte abgelöst werden wird, stellt die im Jahr 2018 eingeführte Datenschutz-Grundverordnung (DSGVO) sicher, dass persönliche Daten nur nach entsprechender Einwilligung durch den Erzeuger der Daten genutzt werden dürfen.
Ligand exchange of phosphine-stabilized undecagold precursor particles, Au11(PPh3)8Cl3, with ω-functionalized thiols provides a convenient and general approach for the rapid preparation of large ...families of thiol-stabilized, subnanometer (d CORE ∼ 0.8 nm) particles. The approach permits rapid incorporation of specific functionality into the stabilizing ligand shell, is tolerant of a wide range of functional groups, and provides convenient access to new materials inaccessible by other methods. Mechanistic studies and trapping experiments give insight into the progression of the ligand exchange, providing evidence that the core size of the phosphine-stabilized undecagold precursor particles is preserved during ligand exchange. The optical properties of the thiol-stabilized nanoparticles depend strongly on the composition of the ligand shell, and a series of studies suggests that this dependence is a result of the ligand shell's influence on the electronic structure of the particle core, as opposed to a structural change within the nanoparticle core.
Non-invasive ventilation (NIV) has been shown to improve survival and quality of life in COPD patients with chronic hypercapnic respiratory failure. However, the proportion of COPD patients with ...chronic hypercapnia is not yet known and clinical data enabling better identification of patients are scarce. The HOmeVent registry was initiated to determine the prevalence of chronic hypercapnia in COPD in an outpatient setting and to evaluate the predictors of hypercapnia.
HOmeVent is a multicenter, prospective, observational, non-interventional patient registry that includes COPD patients in GOLD stage 3 or 4. Eligible patients were identified and enrolled in an outpatient setting during routine clinic visits. Assessments included blood gas analyses, pulmonary function testing and quality of life assessment.
Ten outpatient clinics in Germany enrolled 231 COPD patients in the registry (135 in GOLD stage 3 (58%) and 96 in GOLD stage 4 (42%)). Arterial carbon dioxide pressure (PaCO
) was ≥45 mmHg in 58 patients (25%); of these, 20 (9%) had PaCO
≥50 mmHg. The prevalence of hypercapnia at both cut-off values was numerically higher for patients in GOLD stage 4 versus 3. An increased body mass index, a decreased forced vital capacity and an increased bicarbonate level were significant independent predictors of hypercapnia. The proportion of patients who received NIV was 6% overall and 22% of those with hypercapnia.
A relevant proportion of COPD patients in GOLD stage 3 and 4 exhibits chronic hypercapnia and might, therefore, be candidates for long-term domiciliary NIV treatment.
Background
There are limited data on long-term mortality in sleep apnoea (SA) patients with and without positive airway pressure (PAP) therapy. This retrospective cohort study investigated long-term ...hospitalisation and mortality rates in SA patients from a German statutory health insurance (SHI) database who did versus did not receive PAP therapy.
Methods
Patients had continuous insurance coverage from 01 January 2008 to 31 December 2013, complete medical records and ≥1 SA-related diagnosis in 2009. Those receiving PAP were matched with a control group not treated with PAP. Outcomes (hospitalisations including stays in the sleep laboratory) were compared between groups the year prior to and the 4 years after SA diagnosis. Mortality was assessed in the 4 years after SA diagnosis.
Results
2176 PAP therapy recipients were matched with 2176 controls. The PAP group had a higher rate of hospitalisation in the year before SA diagnosis than the control group (80.2% vs. 26.6%;
p
= 0.0016). After diagnosis, the PAP group had a higher hospitalisation rate only in year 1 (
p
< 0.05), and average length of stay per hospitalisation was lower in the PAP group (
p
< 0.05 vs. control at years 1, 2 and 4). Cumulative all-cause mortality after year 3 (3.4% vs. 4.6%;
p
= 0.0287) and after year 4 (4.8% vs. 6.5%;
p
= 0.0175) was significantly lower in SA patients receiving PAP versus controls (relative risk reduction for death after 4 years: 25.5%).
Conclusion
This real-world cohort study showed an association between long-term PAP therapy use and lower mortality, a higher rate of hospitalisations before and shorter hospital stays after treatment initiation.
A convenient preparation is reported for a series of functionalized, thiol-stabilized gold particles with subnanometer core diameters (d CORE = 0.8 ± 0.2 nm). The preparation produces previously ...inaccessible materials through ligand exchange reactions of a phosphine-stabilized precursor, Au11(PPh3)8Cl3, with ω-functionalized alkanethiols. Convenient access to these new materials is a prerequisite to the detailed study of the electronic and optical properties of subnanometer particles and the investigation of the utility of these building blocks in nanoscale devices. Preliminary investigations of the optical properties of these new materials by UV−vis spectroscopy revealed that the particles have defined optical transitions. These results confirm the presence of discrete energy levels in the electronic structure of these materials that might be expected due to quantum size effects. Initial studies also suggest that the optical properties depend on the nature of the stabilizing ligand shell. The ligand exchange method described is applicable for a diverse family of alkanethiols to produce both organic- and water-soluble particles that show increased stability over the phosphine-stabilized precursor. Extensive characterization indicates that the thiol-stabilized exchange products have well-defined core sizes and dispersities.
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