26 research outputs found
Tumor location determines midkine level and its association with the disease progression in colorectal cancer patients: a pilot study
Primary tumor location in stage III colon cancer has prognostic impact on subsequent liver metastasis
Differences in Cancer-Specific Mortality of Right- Versus Left-Sided Colon Adenocarcinoma: A Surveillance, Epidemiology, and End Results Database Analysis
Nurses’ knowledge about perioperative care of patients with neurological diseases
This study investigated the level of nurses’ knowledge regarding the perioperative care of neurological patients. An author-developed questionnaire of 20 items was used in a sample of 94 hospital nurses serving in the neurology, surgery and anesthesiology departments and the intensive care unit. The average percentage of participants with correct answers was 49.2%. The mean value of participants' score was 9.8 ±3.4. Preexisting experience in the care of cases with multiple sclerosis and Parkinson’s disease was positively related to the level of knowledge (p = 0.001 and 0.014 respectively). The ascertained level of nurses' knowledge regarding the perioperative care of neurological patients was moderate, questioning their adequacy to handle such cases. Previous experience in the care of particular diseases had significantly positive impact on knowledge, suggesting potential improvement strategies through targeted education and specialization of nurses. In conclusion, nurse's knowledge regarding perioperative care of neurological patients was insufficient, requiring appropriate improvement interventions. © The Author(s) 2018
Emission from the stable Blatter radical
Spectroscopic studies reveals broadband emission that spans the visible range originating from excited electronic states of the stable Blatter radical.</p
Doping-induced decomposition of organic semiconductors: a caveat to the use of Lewis acid p-dopants
Solution-processable molecular dopants are popular wet-lab mediators to engineer the electronic properties of organic semiconductors and to optimize the level performance of their corresponding devices. Nonetheless, the exact doping mechanism that is operative during the interaction of organic semiconductors with Lewis acid species is not fully elaborated. The products of the doping reactions between Lewis acids and organic semiconductors have not been studied in detail. Here we focus on the macromolecular poly[bis(4-phenyl)(2,4-dimethylphenyl)]amine (PTAA) and molecular fluorinated anthradithiophene (diF-TES-ADT) organic semiconductors for addressing their chemical integrity after p-doping by the tris(pentafluorophenyl) borane [B(C6F5)3] Lewis acid agent. The PTAA and diF-TES-ADT organic substrates are studied in mixtures with B(C6F5)3 at three discrete concentration regimes. In the dilute solution regime, UV-Vis absorption spectroscopy verifies the effectiveness of p-doping by the changes observed in the absorption spectra of the solutions at increased B(C6F5)3 content. In the concentrated solution regime, the reactivity of B(C6F5)3 with PTAA and diF-TES-ADT is monitored by proton nuclear magnetic resonance (1H-NMR) and electrospray ionization mass spectroscopy (ES-MS), as well as thin-layer chromatography (TLC). Finally, in the solid-state the photophysical properties of spin-coated PTAA:B(C6F5)3 and diF-TES-ADT:B(C6F5)3 films are examined as a function of their B(C6F5)3 content. Density functional theory (DFT) calculations corroborate the experimental findings. Both theoretical and experimental results exclude the formation of Lewis adduct species in the PTAA:B(C6F5)3 and diF-TES-ADT:B(C6F5)3 systems. In agreement with recent literature, the B(C6F5)3 reactivity is attributed to the Brønsted-type acidity of the hydrated B(C6F5)3-OH2 complex that induces p-doping via the protonation of the organic substrates. The formation of the B(C6F5)3-OH2 acidic agent is identified experimentally by its characteristic 1H-NMR signal at 4.7 ppm. All results for the three concentration regimes provide evidence for the occurrence of PTAA and diF-TES-ADT decomposition in the presence of B(C6F5)3. At high B(C6F5)3 loadings, ES-MS spectroscopy and TLC analysis suggest that B(C6F5)3 remains unreacted, revealing the catalytic role in the decomposition process of PTAA and diF-TES-ADT. The results suggest that after interacting with Lewis acids, organic semiconductors may undergo detrimental decomposition reactions. This potentially undesired chemical reactivity should be considered for evaluating the operation stability of the p-doped electronic devices. © 2022 The Royal Society of Chemistry
Size-dependent charge transfer in blends of Pbs quantum dots with a low-gap silicon-bridged copolymer
The photophysics of bulk heterojunctions of a high-performance, low-gap silicon-bridged dithiophene polymer with oleic acid capped PbS quantum dots (QDs) are studied to assess the material potential for light harvesting in the visible- and IR-light ranges. By employing a wide range of nanocrystal sizes, systematic dependences of electron and hole transfer on quantum-dot size are established for the first time on a low-gap polymer-dot system. The studied system exhibits type II band offsets for dot sizes up to ca. 4 nm, whch allow fast hole transfer from the quantum dots to the polymer that competes favorably with the intrinsic QD recombination. Electron transfer from the polymer is also observed although it is less competitive with the fast polymer exciton recombination for most QD sizes studied. The incorporation of a fullerene derivative provides efficient electron-quenching sites that improve interfacial polymer-exciton dissociation in ternary polymer-fullerene-QD blends. The study indicates that programmable band offsets that allow both electron and hole extraction can be produced for efficient light harvesting based on this low-gap polymer-PbS QD composite
InGaN nanohole arrays coated by lead halide perovskite nanocrystals for solid-state lighting
Down-conversion of light via phosphors is central to the generation of white and multi-color emission for solid-state lighting. Lead halide perovskite nanocrystals (NCs) are viable contenders to phosphors as they offer higher emission yields with narrower linewidth and facile synthesis and compositional tunability across the visible. Herein, we employ green-emitting CsPbBr3 and FAPbBr3 and near infrared-emitting FAPbI3 NCs to efficiently down-convert the emission of InGaN/GaN structures. The nitride wafers are patterned into nanohole arrays which are filled by the perovskite NCs to minimize the nitride-NC separation while increasing the heterointerfacial area, thus improving light conversion via both non-radiative resonant and radiative energy transfer. The efficient quenching of the nitride emission dynamics in the presence of the NC overlayers accompanied by a concurrent increase of the NC emission, provides evidence of efficient light down-conversion with efficiencies as high as ~83±6% in the green and ~74±5% in the near-IR
Size-dependent charge transfer in blends of Pbs quantum dots with a low-gap silicon-bridged copolymer
The photophysics of bulk heterojunctions of a high-performance, low-gap silicon-bridged dithiophene polymer with oleic acid capped PbS quantum dots (QDs) are studied to assess the material potential for light harvesting in the visible- and IR-light ranges. By employing a wide range of nanocrystal sizes, systematic dependences of electron and hole transfer on quantum-dot size are established for the first time on a low-gap polymer-dot system. The studied system exhibits type II band offsets for dot sizes up to ca. 4 nm, whch allow fast hole transfer from the quantum dots to the polymer that competes favorably with the intrinsic QD recombination. Electron transfer from the polymer is also observed although it is less competitive with the fast polymer exciton recombination for most QD sizes studied. The incorporation of a fullerene derivative provides efficient electron-quenching sites that improve interfacial polymer-exciton dissociation in ternary polymer-fullerene-QD blends. The study indicates that programmable band offsets that allow both electron and hole extraction can be produced for efficient light harvesting based on this low-gap polymer-PbS QD composite
