Flexible composite film with artificial opal photonic crystals for efficient all-day passive radiative cooling.

All-day passive radiative cooling has recently attracted broader attention for its potential as a viable energy technology. Although tremendous progress has been achieved, the design and fabrication of low-cost high-efficiency radiators for all-day passive radiative cooling remains a challenge. Herein, we report a new type of flexible composite radiator film with built-in artificial opal-like structures for all-day passive radiative cooling. Using artificial opal structure concepts, the proposed polydimethylsiloxane (PDMS) radiator film with embedded polystyrene (PS) microsphere photonic crystals exhibits a sufficiently high solar reflectance of ∼92.7% when in a direct sunlight region, and a thermal emittance of ∼93.6% within the atmospheric window. Without the need for traditional reflectors like silver or aluminum foils, this composite film realizes subambient temperature reduction of ∼4.8 °C in direct sunlight and ∼8.5 °C during the night. This work provides a new fabrication approach for the low-cost production of structural polymer films for high performance and potential real word applications.

Highly linearly polarized light emission from flexible organic light-emitting devices capitalized on integrated ultrathin metal-dielectric nanograting.

Although there have been tremendous achievements ever since the first work on an organic electroluminescent (EL) device that emitted polarized light, the development of flexible polarized emission organic light-emitting devices (OLEDs) is not without hurdles, and the challenge towards real-world applications still requires tremendous effort. In this paper, we proposed highly linearly polarized light-emission from flexible green OLEDs capitalized on integrated ultrathin metal-dielectric nanograting. The acquired polarized device with meticulously optimized geometric parameters yields an angle-invariant average extinction ratio beyond 20.0 dB within a viewing angle range of ± 60°. The detailed analysis illustrates that surface plasmons and cavity modes are simultaneously contributed to the TM-polarized light selection. We hope that the presented approach will open new opportunities for designing flexible polarized light sources.

Laser speckle formed disordered micro-meander structures for light extraction enhancement of flexible organic light-emitting diodes.

A new approach for efficiently recovering the wasted light energy in conventional flexible organic light-emitting diodes (FOLEDs) is developed by implementing disordered micro-meander structures (DMMs) via laser speckle holography technology. Compared to conventional flat device architecture, the structured FOLEDs with DMMs result in substantial improvement of the device efficiency and superior angular color stability. The resulting current efficiency (CE) and external quantum efficiency (EQE) are 1.31 and 1.39 times that of a common flat structure, respectively. Moreover, the proposed DMMs micro-structure simultaneously offers the unique characteristics of angular color stability with a wide viewing angle, which is usually considered as the criteria of the high-quality lighting applications. We hope that the demonstrated method could provide an alternative way for the development of high efficiency flexible OLEDs.

[Microsurgical anatomy and clinical application of infratentorial supracerebellar keyhole approach].

OBJECTIVE: To explore the feasibility of applying the infratentorial supracerebellar keyhole approach for removing tumors of pineal region. METHODS: Infratentorial supracerebellar keyhole approach was performed in 16 cadaveric heads with intracranial vessels perfused by colored latex. The microscopic structure was observed. The anatomic structure was measured with Stryker Navigation System and the data were analyzed with the SPSS 10.0 software. And further, infratentorial supracerebellar keyhole approach was performed in 11 clinical cases with tumors located in the posterior third ventricle and pineal region, based on the individualized imaging features. RESULTS: Only the central group bridging veins on the cerebellum tentorial surface needed to be sacrificed under infratentorial supracerebellar keyhole approach, and other vessels could be preserved well. The distance between the bridging veins of both left and right medial group could reach (35 +/- 6) mm when they were fully dissected, thus offering enough surgical space for applying this keyhole approach. When the culmen of cerebellum was retracted, the pineal body, Galen vein and its tributary, quadrigeminal bodies, even trochlear nerve could be observed. When the underlayer choroid of the third ventricular roof was dissected medially and inferiorly to the posterior choroidal artery, the posterior third ventricle could be reached. If the tentorium of cerebellum was cut open between the straight sinus and the lateral sinus, the surgical field could be enlarged anteriorly and superiorly to the longitudinal fissure region above the tentorium. Eight of the 11 pineal region tumors sized 2-5 cm in diameter were totally removed, and 3 were subtotally resected. For one case, posterior cranial fossa decompression and ventriculoperitoneal shunt were performed postoperatively. Another one patient suffered from transient mutism and steady fixation after surgery. Other patients had no adverse effect. CONCLUSIONS: Infratentorial supracerebellar keyhole approach can be applied for removing the pineal region tumors without interfering the adjacent deep venous system, and can enter the third ventricle in a nearly non-traumatic way. If necessary the tentorium can be cut open to expose supra-tentorial structures. It can be regarded as a better choice for surgeries in this region.

Multifunctional Silver Nanoparticle Interlayer-Modified ZnO as the Electron-Injection Layer for Efficient Inverted Organic Light-Emitting Diodes.

The insufficient electron injection constitutes the major obstacle to achieving high-performance inverted organic light-emitting diodes (OLEDs). Here, a facile electron-injection architecture featuring a silver nanoparticle (AgNPs) interlayer-modified sol-gel-derived transparent zinc oxide (ZnO) ultrathin film is proposed and demonstrated. The optimized external quantum efficiencies of the developed inverted fluorescent and phosphorescent OLEDs capitalized on our proposed electron-injection structure reached 4.0 and 21.2% at a current density of 20 mA cm-2 and increased by a factor of 1.90 and 2.86 relative to a reference device without the AgNP interlayer, while simultaneously reducing the operational voltage and substantially ameliorating the device efficiency. Detailed analyses reveal that the local surface plasmon resonance emanated from AgNPs plays three meaningful roles simultaneously: suppressing the surface plasmon polariton mode loss, aiding in energy-level alignments, and inducing and reinforcing the local exciton-plasmon coupling electric field. Among these interesting and multifunctional roles, the enhanced local exciton-plasmon coupling electric field dominates the electron injection enhancement and substantial increases the device efficiency. Additionally, the light-scattering effect also helps in recovering the trapped light energy flux and thus improves the device efficiency. The proposed approach and findings provide an alternative path to fabricate high-performance inverted OLEDs and other related organic electronic or optoelectronic devices.

Effects of self-assembly of 3-phosphonopropionic acid, 3-aminopropyltrimethoxysilane and dopamine on the corrosion behaviors and biocompatibility of a magnesium alloy.

Magnesium based alloys are attracting tremendous interests as the novel biodegradable metallic biomaterials. However, the rapid in vivo degradation and the limited surface biocompatibility restrict their clinical applications. Surface modification represents one of the important approaches to control the corrosion rate of Mg based alloys and to enhance the biocompatibility. In the present study, in order to improve the corrosion resistance and surface biocompatibility, magnesium alloy (AZ31B) was modified by the alkali heating treatment followed by the self-assembly of 3-phosphonopropionic acid, 3-aminopropyltrimethoxysilane (APTMS) and dopamine, respectively. The results of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectra (XPS) indicated that the molecules were successfully immobilized on the magnesium alloy surface by the self-assembly. An excellent hydrophilic surface was obtained after the alkali heating treatment and the water contact angle increased to some degree after the self-assembly of dopamine, APTMS and 3-phosphonopropionic acid, however, the hydrophilicity of the modified samples was better than that of the pristine magnesium substrate. Due to the formation of the passivation layer after the alkali heating treatment, the corrosion resistance of the magnesium alloy was obviously improved. The corrosion rate further decreased to varying degrees after the self-assembly surface modification. The blood compatibility of the pristine magnesium was significantly improved after the surface modification. The hemolysis rate was reduced from 56% of the blank magnesium alloy to 18% of the alkali heating treated sample and the values were further reduced to about 10% of dopamine-modified sample and 7% of APTMS-modified sample. The hemolysis rate was below 5% for the 3-phosphonopropionic acid modified sample. As compared to the pristine magnesium alloy, fewer platelets were attached and activated on the modified surfaces and the activated partial thromboplastin times (APTT) were prolonged to some degree. Furthermore, the modified samples showed good cytocompatibility. Endothelial cells exhibited the improved proliferative profiles in terms of CCK-8 assay as compared to those on the pristine magnesium alloy. The modified samples showed better endothelial cell adhesion and spreading than the pristine magnesium alloy. Taking all these results into consideration, the method of this study can be used to modify the magnesium alloy surface to improve the corrosion resistance and biocompatibility simultaneously.

Construction of recombinant adenoviral vector overexpressing human HIF-1alpha gene.

Hypoxia inducible factor 1 (HIF-1) is a heterodimeric transcription factor that plays an important role in oxygen homeostasis. In response to low level of oxygen, subunit HIF-1alpha expression is upregulated and transactivates its target genes essential for energy metabolism, erythropoiesis and vascular development. HIF-1alpha is thought to be able to protect hypoxic cells from apoptosis or necrosis under ischemic and anoxic conditions, the major trauma factors that affect the recovery of brain and spinal cord injury. Here we report the construction of recombinant adenovirus vector overexpressing HIF-1alpha intended for gene therapy against desired neuronal injuries. The recombinant vector could be packaged and yielded significantly high viral titers at 2 x 10(13) CFU in HEK293T cells and good expression levels of HIF-1alpha when superinfected in Hela cells.