The applicability of the "surprise question" as a prognostic tool in patients with severe chronic comorbidities in a university teaching outpatient setting.

BACKGROUND: Life expectancy in recent decades has increased the prevalence of chronic diseases in the population, requiring an approach to new health topics, such as discussions on quality of life and expectations about death and dying. The concept of advance directives (ADs) gives individuals the opportunity to make known their decisions about the treatments they would like to receive at the end of life. Despite the recognition of relevance in clinical practice, the applicability of the concept presents challenges, including establishing the appropriate prognosis for each patient and the ideal time to approach the patient. Some prognostic tools were developed, such as the surprise question (SQ): "Would you be surprised if your patient died in 12 months?", which is used in some clinical settings to predict patient deaths and to make decisions regarding ADs. The main objective of the present study was to evaluate the behavior of second-year resident physicians (PGY-2) when the SQ was applied. METHOD: In our observational study, from July 1, 2016, to February 28, 2017, (PGY-2) in the Internal Medicine Residency Program (IMRP) applied SQ to all patients with multiple and varied chronic no communicable comorbidities, who were followed up at the general medicine outpatient clinic (GMOC) of a tertiary university hospital in São Paulo- Brazil. The frequency of the outcome (death or non-death within 12 months) was analyzed by correlating it with the clinical data (impact of the studied variables). RESULTS: Eight hundred forty patients entered the study. Fitfty-two of them (6.2%) died within one year. PGY-2 predicted that two hundred and fourteen patients (25.5% of total) would die within a year (answer No to SQ), of which, 32 (14.9%) did so. The correct residents' prognosis for the subgroup of 626 patients (answer "Yes" to SQ) was NPV = 96.8% (CI = 95.4%-98.2%) and PPV = 14.9% (CI 10.1%-19, 6%). Answering "Yes" to SQ correlated negatively to addressing AD while the outcomes death and the answer No to SQ were positively correlated, according to the number of comorbidities. CONCLUSION: The SQ, in addition to care, contributed to health education, communication and care planning shared by the doctor and patient.

MicroRNA-409 promotes recovery of spinal cord injury by regulating ZNF366.

OBJECTIVE: To explore the role of microRNA-409 in spinal cord injury (SCI) recovery and its underlying mechanism. MATERIALS AND METHODS: The mouse SCI model was first established, and the difference in recovery of grip strength was detected. MicroRNA-409 expressions in mice tissues from sham operation group and SCI group were detected by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). We further increased microRNA-409 level in mice spinal cord by plasmids transfection. Luciferase activity was detected to verify the direct binding of microRNA-409 and ZNF366. RESULTS: The grip strength in both groups was temporarily decreased after surgery, while the grip strength in SCI group was always remarkably lower than that of the sham operation group since the first week after the surgery, suggesting the successful construction of mouse SCI model. MicroRNA-409 expression in the SCI group was gradually decreased from the postoperative 3rd day, which was remarkably lower than that of the sham group. Additionally, ZNF366 expression in the SCI group began to increase from the first day after the surgery, which was markedly higher than that of the sham group. After injection of exogenous microRNA-409, ZNF366 expression in the SCI group showed a remarkable decrease compared to that of the sham operation group. We also confirmed that ZNF366 was the target gene of microRNA-409 by bioinformatics analysis and luciferase activity assay. CONCLUSIONS: MicroRNA-409 is downregulated after spinal cord injury. Overexpression of microRNA-409 directly targets ZNF366 and promotes the recovery of spinal cord injury.

Study on the role of Hsa-miR-382-5p in epidural fibrosis.

OBJECTIVE: To investigate the role and potential mechanism of human serum albumin (hsa)-micro ribonucleic acid (miR)-382-5p in epidural fibrosis formation after laminectomy. MATERIALS AND METHODS: Cells were transfected with miR-382-5p mimic or miR-382-5p inhibitor. Then, 3-(4,5)-dimethylthiahiazol (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay was employed to detect the effect of miR-382-5p on proliferation, and Real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to examine the expressions of miR-382-5p and fibrosis-related proteins after treatment with transforming growth factor beta (TGF-ß). Luciferase assay and immunofluorescent staining were done to confirm whether collagen I A1 is a target of miR-382-5p. RESULTS: MTT assay demonstrated that miR-382-5p had no significant effect on fibroblast proliferation. Expressions of miR-382-5p and fibrosis-related proteins were remarkably increased after TGF-ß treatment. Collagen I A1 was acknowledged as a target of miR-382-5p. MiR-382-5p mimic statistically enhanced the level of collagen I A1, and miR-382-5p enhanced the expressions of collagen I A1. CONCLUSIONS: Increased miR-382-5p promotes epidural fibrosis by increasing collagen I A1 expression, and miR-382-5p may be a potential novel molecular target for the treatment of epidural fibrosis.

Synthesis of N-doped graphene quantum dots by pulsed laser ablation with diethylenetriamine (DETA) and their photoluminescence.

We report a facile, fast, and one-step approach to prepare N-doped graphene quantum dots (GQDs) using pulsed laser ablation with diethylenetriamine (DETA). The synthesized N-doped GQDs with an average size of about 3.4 nm and an N/C atomic ratio of 26% have been demonstrated. Compared to pristine GQDs, the N-doped GQDs emit enhanced photoluminescence (PL) with a factor as high as 66, originated from the enhanced densities of pyridinic and graphitic N. The temperature-dependent PL of the N-doped GQDs was studied from cryogenic to room temperature. An anomalous temperature dependence of PL intensity was observed for the N-doped GQDs, which was ascribed to a carrier transfer mechanism from a dopant-induced state to the quantum-dot emitting state.

Eco-friendly luminescent solar concentrators with low reabsorption losses and resistance to concentration quenching based on aqueous-solution-processed thiolate-gold nanoclusters.

Heavy-metal-containing quantum dots (QDs) with engineered electronic states have been served as luminophores in luminescent solar concentrators (LSCs) with impressive optical efficiency. Unfortunately, those QDs involve toxic elements and need to be synthesized in a hazardous solvent. Recently, biocompatible, eco-friendly gold nanoclusters (AuNCs), which can be directly synthesized in an aqueous solution, have gained much attention for promising applications in 'green photonics'. Here, we explored the solid-state photophysical properties of aqueous-solution-processed, glutathione-stabilized gold nanoclusters (GSH-AuNCs) with a ligand-to-metal charge-transfer (LMCT) state for developing 'green' LSCs. We found that such GSH-AuNCs exhibit a large Stokes shift with almost no spectral overlap between the optical absorption and PL emission due to the LMCT states, thus, suppressing reabsorption losses. Compared with GSH-AuNCs in solution, the photoluminescence quantum yields (PL-QYs) of the LSCs can be enhanced, accompanied with a lengthened PL lifetime owing to the suppression of non-radiative recombination rates. In addition, the LSCs do not suffer from severe concentration-induced PL quenching, which is a common weakness for conventional luminophores. As a result, a common trade-off between light-harvesting efficiency and solid-state PL-QYs can be bypassed due to nearly-zero spectral overlap integral between the optical absorption and PL emission. We expect that GSH-AuNCs hold great promise for serving as luminophores for 'green' LSCs by further enhancing solid-state PL-QYs.

Origin of tunable photoluminescence from graphene quantum dots synthesized via pulsed laser ablation.

A one-step synthesis of graphene quantum dots (GQDs) has been implemented using pulsed laser ablation (PLA) with carboxyl-functionalized multiwalled carbon nanotubes (MWCNTs). The synthesized GQDs with an average size smaller than 3 nm were obtained by the fragmentation of MWCNTs via oxidative cutting. The GQDs can generate tunable photoluminescence (PL) ranging from green to blue by controlling the PLA time. The PL spectrum (decay time) of the green GQDs remains unchanged under different excitation energies (emission energies), while that of the blue GQDs correlates with the excitation energy (emission energy). On the basis of the pH and temperature dependence of PL, we suggest that the localized intrinsic states associated with the sp(2) nanodomains and delocalized extrinsic states embedded on the GQD surface are responsible for blue and green emission in GQDs, respectively.

Solid-state, ambient-operation thermally activated delayed fluorescence from flexible, non-toxic gold-nanocluster thin films: towards the development of biocompatible light-emitting devices.

Luminescent gold nanoclusters (AuNCs) with good biocompatibility have gained much attention in bio-photonics. In addition, they also exhibit a unique photo-physical property, namely thermally activated delayed fluorescence (TADF), by which both singlet and triplet excitons can be harvested. The combination of their non-toxic material property and unique TADF behavior makes AuNCs biocompatible nano-emitters for bio-related light-emitting devices. Unfortunately, the TADF emission is quenched when colloidal AuNCs are transferred to solid states under ambient environment. Here, a facile, low-cost and effective method was used to generate efficient and stable TADF emissions from solid AuNCs under ambient environment using polyvinyl alcohol as a solid matrix. To unravel the underlying mechanism, temperature-dependent static and transient photoluminescence measurements were performed and we found that two factors are crucial for solid TADF emission: small energy splitting between singlet and triplet states and the stabilization of the triplet states. Solid TADF films were also deposited on the flexible plastic substrate with patterned structures, thus mitigating the waveguide-mode losses. In addition, we also demonstrated that warm white light can be generated based on a co-doped single emissive layer, consisting of non-toxic, solution-processed TADF AuNCs and fluorescent carbon dots under UV excitation.

A Facile and Low-Cost Method to Enhance the Internal Quantum Yield and External Light-Extraction Efficiency for Flexible Light-Emitting Carbon-Dot Films.

Solution-processed, non-toxic carbon dots (CDs) have attracted much attention due to their unique photoluminescence (PL) properties. They are promising emissive layers for flexible light-emitting devices. To this end, the CDs in pristine aqueous solutions need to be transferred to form solid-state thin films without sacrificing their original PL characteristics. Unfortunately, solid-state PL quenching induced by extra non-radiative (NR) energy transfer among CDs would significantly hinder their practical applications in optoelectronics. Here, a facile, low-cost and effective method has been utilized to fabricate high-performance CD/polymer light-emitting flexible films with submicron-structured patterns. The patterned polymers can serve as a solid matrix to disperse and passivate CDs, thus achieving high internal quantum yields of 61%. In addition, they can act as an out-coupler to mitigate the waveguide-mode losses, approximately doubling the external light-extraction efficiency. Such CD/polymer composites also exhibit good photo-stability, and thus can be used as eco-friendly, low-cost phosphors for solid-state lighting.

Laser-ablation production of graphene oxide nanostructures: from ribbons to quantum dots.

A new one-step method for the preparation of graphene oxide (GO) nanostructures has been developed by pulsed laser ablation in GO solution. The formation of different shapes of GO nanostructures, such as ribbons, nanoflakes (including nano-squares, nano-rectangles, nano-triangles, nano-hexagons, and nano-disks) and quantum dots, has been demonstrated by scanning electron microscopy and transmission electron microscopy. Photoreduction for the GO occurred during irradiation by the pulsed laser. The GO quantum dots exhibit a blue photoluminescence, originating from recombination of the localized carriers in the zigzag-edge states.

Probing the photoluminescence properties of gold nanoclusters by fluorescence lifetime correlation spectroscopy.

Gold nanoclusters (Au NCs) have attracted much attention for promising applications in biological imaging owing to their tiny sizes and biocompatibility. So far, most efforts have been focused on the strategies for fabricating high-quality Au NCs and then characterized by conventional ensemble measurement. Here, a fusion single-molecule technique combining fluorescence correlation spectroscopy and time-correlated single-photon counting can be successfully applied to probe the photoluminescence (PL) properties for sparse Au NCs. In this case, the triplet-state dynamics and diffusion process can be observed simultaneously and the relevant time constants can be derived. This work provides a complementary insight into the PL mechanism at the molecular levels for Au NCs in solution.

Distance dependence of energy transfer from InGaN quantum wells to graphene oxide.

We report the distance-dependent energy transfer from an InGaN quantum well to graphene oxide (GO) by time-resolved photoluminescence (PL). A pronounced shortening of the PL decay time in the InGaN quantum well was observed when interacting with GO. The nature of the energy-transfer process has been analyzed, and we find the energy-transfer efficiency depends on the 1/d² separation distance, which is dominated by the layer-to-layer dipole coupling.

Efficient energy transfer from InGaN quantum wells to Ag nanoparticles.

Nonradiative energy transfer from an InGaN quantum well to Ag nanoparticles is unambiguously demonstrated by the time-resolved photoluminescence. The distance dependence of the energy transfer rate is found to be proportional to 1/d(3), in good agreement with the prediction of the dipole interaction calculated from the Joule losses in acceptors. The maximum energy-transfer efficiency of this energy transfer system can be as high as 83%.

n-ZnO/LaAlO3/p-Si heterojunction for visible-blind UV detection.

A visible-blind UV photodetector (PD) using a double heterojunction of n-ZnO/LaAlO3 (LAO)/p-Si was demonstrated. Inserted LAO layers exhibit electrical insulating properties and serve as blocking layers for photoexcited electrons from p-Si to n-ZnO, leading to an enhanced rectification ratio and a visible-blind UV detectivity of the n-ZnO/LAO/p-Si PDs due to the high potential barrier between LAO and p-Si layers (~2.0 eV). These results support the use of n-ZnO/LAO/p-Si PDs in the visible-blind UV PDs in a visible-light environment.

Solar energy harvesting scheme using syringe-like ZnO nanorod arrays for InGaN/GaN multiple quantum well solar cells.

Syringe-like ZnO nanorod arrays (NRAs) synthesized by a hydrothermal method were applied as the light-harvesting layer on InGaN-based multiple quantum well (MQW) solar cells. Theoretical calculations show that the NRAs with an abrupt shrinkage of tip diameter can further suppress surface reflectance in comparison with the flat NRAs. InGaN-based MQW solar cells with the syringe-like NRAs exhibit greatly improved conversion efficiencies by 36%. These results are attributed to the improved flatness of the refractive index profile at the air/device interface, which results in enhanced light trapping effect on the device surface.

Energy transfer from InGaN quantum wells to Au nanoclusters via optical waveguiding.

We present the first observation of resonance energy transfer from InGaN quantum wells to Au nanoclusters via optical waveguiding. Steady-state and time-resolved photoluminescence measurements provide conclusive evidence of resonance energy transfer and obtain an optimum transfer efficiency of ~72%. A set of rate equations is successfully used to model the kinetics of resonance energy transfer.

Single fluorescent gold nanoclusters.

Both ensemble and single-molecule measurements were performed to explore the fluorescence properties of Au nanoclusters (NCs). Photoinduced fluorescence enhancement was observed for ensemble NCs in solution, but photobleaching was found at ambient environments. At the single-molecule level, fluorescence blinking and single-step photobleaching were observed. Furthermore, their time-resolved fluorescence shows a single exponential decay with a lifetime of approximately 7 ns and is insensitive to changes in fluorescence intensity. The lifetime distribution is more homogeneous within ensemble Au NCs as compared to CdSe QDs. Therefore, Au NCs have potential applications as nontoxic fluorescent labels for lifetime-based imaging microscopy. However, their low quantum yields and poor photostability are disadvantageous factors, which require further improvement.

ZnO/Al2O3 core-shell nanorod arrays: growth, structural characterization, and luminescent properties.

We report an aqueous chemical method to fabricate well-aligned ZnO/Al(2)O(3) nanocrystal (NC) core-shell nanorod arrays (NRAs). Structural characterization showed that the shell layers are composed of alpha-Al(2)O(3) nanocrystals. Photoluminescence measurements showed the enhancement of near-band-edge (NBE) emission of ZnO NRAs due to the presence of Al(2)O(3) NC shells. The Al(2)O(3) NC shell layer resulting in the flat-band effect near the ZnO surface leads to a stronger overlap of the wavefunctions of electrons and holes in the ZnO core, further enhancing the NBE emission. This approach should be very useful in designing many other core-shell NRAs for creating varieties of high-efficiency optoelectronic devices.

Improvement of conversion efficiency for multi-junction solar cells by incorporation of Au nanoclusters.

We studied the photoluminescence (PL) and photovoltaic current-voltage characteristics of the three-junction InGaP/InGaAs/Ge solar cells by depositing Au nanoclusters on the cell surface. The increases of the PL intensity and short-circuit current after incorporation of Au nanoclusters are evident. An increase of 15.3% in energy conversion efficiency (from 19.6 to 22.6%) is obtained for the three-junction solar cells in which Au nanoclusters have been incorporated. We suggest that the increased light trapping due to radiative scattering from Au nanoclusters is responsible for improving the performance of the three-junction solar cells.

Cardiac arrhythmia emergency room visits and environmental air pollution in Sao Paulo, Brazil.

OBJECTIVES: Air-pollution exposure has been associated with increased cardiovascular hospital admissions and mortality in time-series studies. We evaluated the relation between air pollutants and emergency room (ER) visits because of cardiac arrhythmia in a cardiology hospital. METHODS: In a time-series study, we evaluated the association between the emergency room visits as a result of cardiac arrhythmia and daily variations in SO(2), CO, NO(2), O(3) and PM(10), from January 1998 to August 1999. The cases of arrhythmia were modelled using generalised linear Poisson regression models, controlling for seasonality (short-term and long-term trend), and weather. RESULTS: Interquartile range increases in CO (1.5 ppm), NO(2) (49,5 microg/m(3)) and PM(10) (22.2 microg/m(3)) on the concurrent day were associated with increases of 12.3% (95% CI: 7.6% to 17.2%), 10.4% (95% CI: 5.2% to 15.9%) and 6.7% (95% CI: 1.2% to 12.4%) in arrhythmia ER visits, respectively. PM(10), CO and NO(2) effects were dose-dependent and gaseous pollutants had thresholds. Only CO effect resisted estimates in models with more than one pollutant. CONCLUSIONS: Our results showed that air pollutant effects on arrhythmia are predominantly acute starting at concentrations below air quality standards, and the association with CO and NO(2) suggests a relevant role for pollution caused by cars.

Dramatic enhancement of optical-field-ionization collisional-excitation x-ray lasing by an optically preformed plasma waveguide.

Dramatic enhancement of optical-field-ionization collisional-excitation x-ray lasing is achieved by using an optically preformed plasma waveguide. With a 9-mm-long pure krypton plasma waveguide prepared by using the axicon-ignitor-heater scheme, lasing at 32.8 nm is enhanced by 400 folds relative to the case without the plasma waveguide. An output level of 8 x 10(10) photon/shot is reached at an energy conversion efficiency of 2 x 10(-6). The same method is used to achieve x-ray lasing in a gas jet for the high-threshold low-gain transition at 46.9 nm in neonlike argon.