Articles you may be interested inMorphology and microstructure evolution of Al x Ga 1 − x N epilayers grown on GaN/sapphire templates with AlN interlayers observed by transmission electron microscopy Morphology and microstructure of dislocation etch pits in GaN epilayers etched by molten KOH have been investigated by atomic force microscopy, scanning electron microscopy, and transmission electron microscopy ͑TEM͒. Three types of etch pits ͑␣, , and ␥͒ are observed. The ␣ type etch pit shows an inversed trapezoidal shape, the  one has a triangular shape, and the ␥ type one has a combination of triangular and trapezoidal shapes. TEM observation shows that ␣, , and ␥ types etch pits originate from screw, edge, and mixed-type threading dislocations ͑TDs͒, respectively. For the screw-type TD, it is easily etched along the steps that the dislocation terminates, and consequently, a small Ga-polar plane is formed to prevent further vertical etching. For the edge-type TD, it is easily etched along the dislocation line. Since the mixed-type TDs have both screw and edge components, the ␥ type etch pit has a combination of ␣ and  type shapes. It is also found that the chemical stabilization of Ga-polar surface plays an important role in the formation of various types of dislocation etch pits.
The shortened Abstract is as follows: Therapeutic gas nitric oxide (NO) has demonstrated the unique advances in biomedical applications due to its prominent role in regulating physiological/pathophysiological activities in terms of vasodilation, angiogenesis, chemosensitizing effect, and bactericidal effect. However, it is challenging to deliver NO, due to its short half-life (<5 s) and short diffusion distances (20-160 µm). To address these, various polymeric NO delivery nanoplatforms (PNODNPs) have been developed for cancer therapy, antimicrobial and cardiovascular therapeutics, because of the important advantages of polymeric delivery nanoplatforms in terms of controlled release of therapeutics and the extremely versatile nature. This reviews highlights the recent significant advances made in PNODNPs for NO storing and targeting delivery. The ideal and unique criteria that are required for PNODNPs for treating cancer, cardiovascular diseases and infection, respectively, are summarized. Hopefully, effective storage and targeted delivery of NO in a controlled manner using PNODNPs could pave the way for NO-sensitized synergistic therapy in clinical practice for treating the leading death-causing diseases.
in bioimaging application. On the other hand, great research interest has been focused on pure organic persistent RTP materials in recent years because they exhibit superior environmental friendliness, low cost, good biocompatibility, impressive stability, and easy modification. To meet the requirements of intravital bioimaging, the development of effective and ultralong pure organic RTP materials is desirable, where the promotion of intersystem crossing (ISC) and inhibition of nonradiative decay play key roles.Two approaches are summarized in accordance with the first-order perturbation theory and the Marcus semiclassical approach: [5] One approach is to increase the spin-orbital coupling (SOC) and promote the ISC processes by introducing heteroatoms with lone pair electrons, [6] heavy atoms, [7] or carbonyls; [8] the other approach is to suppress the nonradiative relaxation pathways and subsequently stabilize the triplet excitons in a stiff environment by forming crystals, [9] polymer assistance, [10] H-aggregation, [11] host-guest combination, [12] etc. With unremitting efforts, impressive advancements have been made in the past decade. For instance, Kim and co-workers developed an efficient pure organic RTP system to realize materials with bright RTP and a quantum yield (Φ) of 55% by forming cocrystals with a similar halogen-bonding motif. [13] Moreover, Huang and co-workers developed a new strategy for prolonging the phosphorescence lifetime by using d-pπ bonds to regulate the excited-state electronic configuration of pure organic Pure organic persistent room temperature phosphorescence (RTP) materials have attracted wide attention owing to their great potential in various applications, particularly in bioimaging. However, it is still a challenge to manufacture organic RTP materials possessing quite high efficiency and long lifetime, owing to the high requirements for triplet excitons. In this study, a series of keto derivatives with efficient RTP in crystals are developed through the regulation of molecular aggregation states by simple alkyl groups, resulting in impressive luminescence performance with a longer lifetime and higher efficiency of up to 868 ms and 51.59%, respectively. All the alkyl-substituted derivatives exhibit bright RTP intensities after heavy grinding with a pestle, indicating their robust RTP features, which are suitable for many fields. Encouraged by the excellent RTP performance of these luminogens in the crystalline state, successful orthotopic lung tumor imaging with a high signal-to-background ratio (SBR) of 65 is demonstrated in this study to provide the promise of pure organic RTP materials for disease diagnosis, which hold the advantages of low autofluorescence interference and high signal-to-background ratio.
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