Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Electrode architectural engineering for enhancing solar conversion efficiency

Population explosion and significant advancement in technology have dramatically increased global energy demand. Currently, fossil fuel-based power generators remain as our primary power supply. However, fossil fuels are nonrenewable energy resources and its combustion will result in severe environmental problems. Therefore, there is an urgent obligation for our generation to develop practical sustainable energy resources that will address the issue of dwindling fossil fuels and reduce environmental degradation. The energy influx from the sun to earth per hour is roughly equal to the yearly energy consumption across the world. There is hence a general belief that photovoltaic (PV) devices are the most promising in satisfying the drastically inflating energy demand. The fast-expanding knowledge in nanotechnology and material science have contributed to the development of nanomaterials with fascinating features. Integrating materials nanotechnology in electrode design may bring us new opportunities to craft groundbreaking next-generation devices. Electrode architectural engineering is particularly important in fabricating high-performance PV cells to attain excellent charge transport/transfer properties and desirable electrochemical reaction kinetics. The mission of this interdisciplinary PhD program is to design novel electrode architectures with favorable materials nanostructures and functional properties for improving the solar conversion efficiency of low-cost PV devices, specifically polymer PV devices and dye sensitized solar cells (DSSC), as well as to explore their efficiency enhancement mechanisms, so as to push our current knowledge in electrode design to a new frontier. In order to improve the fill factor of polymer PV devices, uniformly distributed gold nanoparticles (Au NPs) were inserted at the interface between vanadium pentoxide (V2O5) anodic buffer layer and ITO electrode to enhance the charge extraction within the cell. The resultant power conversion efficiency (PCE) of the modified device exhibited a ~16 % enhancement compared to the device without Au NP. Theoretical impedance analysis revealed that a lower charge transport resistance and higher charge recombination resistance, which are key factors leading to an improved fill factor, of the modified OPV device. Moreover, the incorporation of Au NPs have induced a better crystallinity of poly(3-hexylthiophene-2,5-diyl) (P3HT) within the bulk heterojunction networks, hence resulting in enhanced charge transportation process. This study provides new insights into the roles of Au NPs in improving the performance of polymer solar cells. Size-tunable TiO2 mesocrystals with high crystallinity were prepared using a simple solvothermal approach and utilized as the photoanode material of DSSC. The size of the TiO2 mesocrystals was controlled through tuning the hydrolysis rate of titanium alkoxide precursor. The unique well-aligned mesocrystal structure enabled efficient charge transportation pathway within the photoanode, while suppressing the charge recombination at the TiO2/electrolyte interface. Furthermore, the submicronsize mesoporous structure provided a large surface area for dye adsorption and effective light scattering capability. The conversion efficiency of DSSCs was significantly enhanced (~36 %) through the utilization of a mesocrystal TiO2-based photoanode compared to that of a P25 controlled cell. A novel interconnected NiCo2S4 nanosheets network was successfully grown on fluorine-doped tin oxide (FTO) and applied as the counter electrode (CE) of DSSC. Detailed studies revealed that the compositional ratio of NiCo2S4 could significantly affect its catalytic activity in redox mediator regeneration. Furthermore, the development of interconnected nanosheets on electrodes could substantially increase the electrochemically active surface area, thus leading to the improved kinetics of Iregeneration reactions. DSSC assembled using the optimal interconnected NiCo2S4 nanosheets CE exhibited a higher power conversion efficiency (7.22 %) compared to that of a conventional device (6.87 %) employing sputtered Pt CE.DOCTOR OF PHILOSOPHY (SCBE

In situ selective cellular nitric oxide sensing using humanized graphene film

Nitric oxide is a messenger molecule and plays important roles in maintaining physiological function. The abnormality of NO concentration presence in biological body would lead to pathogenesis. This project reports the construction of RGD-peptide grafted graphene film and its application as a selective and flexible sensing matrix for cell released nitric oxide molecule detection. The constructed flexible graphene sensing matrix is characterized using scanning electron microscope, atomic force microscopic, reflection absorption infrared spectroscopy and proteomic test. The results show that the RGD-peptide is successfully grafted onto –COOH functionalized graphene film. Electrochemical characterizations tell that the graphene sensing matrix provides a sensitivity of 10.718 μA/μM, detection limit of 194 nM, and a broad linear range from 4 μM to 0.8 mM. In addition, the sensing matrix also exhibits good biocompatibility for human cells. More importantly, the sensing matrix has demonstrated its capability for in situ dynamic cell nitric oxide molecular detection. This work provides a unique sensing unique sensing matrix for various cell molecular detections.Bachelor of Engineering (Chemical and Biomolecular Engineering

Cesium Carbonate Functionalized Graphene Quantum Dots as Stable Electron-Selective Layer for Improvement of Inverted Polymer Solar Cells

Solution processable inverted bulk heterojunction (BHJ) polymer solar cells (PSCs) are promising alternatives to conventional silicon solar cells because of their low cost roll-to-roll production and flexible device applications. In this work, we demonstrated that Cs2CO3 functionalized graphene quantum dots (GQDs–Cs2CO3) could be used as efficient electron-selective layers in inverted PSCs. Compared with Cs2CO3 buffered devices, the GQDs–Cs2CO3 buffered devices show 56% improvement in power conversion efficiency, as well as 200% enhancement in stability, due to the better electron-extraction, suppression of leakage current, and inhibition of Cs+ ion diffusion at the buffer/polymer interface by GQDs–Cs2CO3. This work provides a thermal-annealing-free, solution-processable method for fabricating electron-selective layer in inverted PSCs, which should be beneficial for the future development of high performance all-solution-processed or roll-to-roll processed PSCs.ASTAR (Agency for Sci., Tech. and Research, S’pore

Graphene quantum dots-incorporated cathode buffer for improvement of inverted polymer solar cells

Graphene quantum dots (GQDs) are an emerging class of nanomaterials with unique photonic and electric properties. In this study, GQDs were prepared by a facile, inexpensive and high-yield hydrothermal method and were further used as a cathode buffer additive for inverted polymer solar cells due to a wide band gap (~3.3 eV) and well-matched energy level between GQDs–cesium carbonate (GQDs–Cs2CO3) modified indium tin oxide (3.8 eV) and high occupied molecular orbit of [6,6]-phenyl-C61-butyric acid methyl ester (3.7 eV). In comparison to inverted polymer solar cells using cesium carbonate (Cs2CO3) buffer layer, the power conversion efficiency of GQDs–Cs2CO3 based device showed 22% enhancement from 2.59% to 3.17% as a result of enhanced exciton dissociation and suppressed free charge recombination at cathode/polymer active layer interface by GQDs. This work provides a new application of GQDs in organic electronic devices.ASTAR (Agency for Sci., Tech. and Research, S’pore

RGD-peptide functionalized graphene biomimetic live-cell sensor for real-time detection of nitric oxide molecules

It is always challenging to construct a smart functional nanostructure with specific physicochemical properties to real time detect biointeresting molecules released from live-cells. We report here a new approach to build a free-standing biomimetic sensor by covalently bonding RGD-peptide on the surface of pyrenebutyric acid functionalized graphene film. The resulted graphene biofilm sensor comprises a well-packed layered nanostructure, in which the RGD-peptide component provides desired biomimetic properties for superior human cell attachment and growth on the film surface to allow real-time detection of nitric oxide, an important signal yet short-life molecule released from the attached human endothelial cells under drug stimulations. The film sensor exhibits good flexibility and stability by retaining its original response after 45 bending/relaxing cycles and high reproducibility from its almost unchanged current responses after 15 repeated measurements, while possessing high sensitivity, good selectivity against interferences often existing in biological systems, and demonstrating real time quantitative detection capability toward nitric oxide molecule released from living cells. This study not only demonstrates a facial approach to fabricate a smart nanostructured graphene-based functional biofilm, but also provides a powerful and reliable platform to the real-time study of biointeresting molecules released from living cells, thus rendering potential broad applications in neuroscience, screening drug therapy effect, and live-cell assays

Improved utilization of photogenerated charge using fluorine-doped TiO2 hollow spheres scattering layer in dye-sensitized solar cells

We demonstrate a strategy to improve utilization of photogenerated charge in dye-sensitized solar cells (DSSCs) with fluorine-doped TiO2 hollow spheres as the scattering layer, which improves the fill factor from 69.4% to 74.1% and in turn results in an overall efficiency of photoanode increased by 13% (from 5.62% to 6.31%) in comparison with the control device using undoped TiO2 hollow spheres. It is proposed that the fluorine-doping improves the charge transfer and inhibition of charge recombination to enhance the utilization of the photogenerated charge in the photoanode

One-Step Fabrication of Unique Mesoporous NiO Hollow Sphere Film on FTO for High-Performance P-Type Dye-Sensitized Solar Cells

P-type dye sensitized solar cells (p-DSCs) deliver much lower overall efficiency than their inverse model, n-DSCs. However, they have fundamental and practical significance, in particular, their tandem structured solar cells with both p- and n-photoelectrodes could offer great potential to significantly improve the efficiency of existing solar cells. A facile and environmentally friendly method is developed to directly one-step grow hollow NiO spherical structures on fluorine-doped tin oxide (FTO) substrate, in which a Ni2+ and polymer complex spherical structure is self-constructed through a controlled solvent evaporation process, followed by calcination-converting to a unique NiO hollow sphere film. The prepared material is further used as a photocathode in p-type dye sensitized solar cells, resulting in 41% increase of an open-circuit voltage and 18% enhancement of power conversion efficiency than NiO nanoparticles photocathode. The improved performance can be ascribed to suppressed charge recombination at the photocathode/electrolyte interface. This template-free approach could be universally used to fabricate other nanostructured hollow spheres for a wide range of energy conversion applications such as electrochemical capacitors, chemical sensors, and electrochromic devices.ASTAR (Agency for Sci., Tech. and Research, S’pore

Cesium Carbonate Functionalized Graphene Quantum Dots as Stable Electron-Selective Layer for Improvement of Inverted Polymer Solar Cells

Solution processable inverted bulk heterojunction (BHJ) polymer solar cells (PSCs) are promising alternatives to conventional silicon solar cells because of their low cost roll-to-roll production and flexible device applications. In this work, we demonstrated that Cs₂CO₃ functionalized graphene quantum dots (GQDs–Cs₂CO₃) could be used as efficient electron-selective layers in inverted PSCs. Compared with Cs₂CO₃ buffered devices, the GQDs–Cs₂CO₃ buffered devices show 56% improvement in power conversion efficiency, as well as 200% enhancement in stability, due to the better electron-extraction, suppression of leakage current, and inhibition of Cs⁺ ion diffusion at the buffer/polymer interface by GQDs–Cs₂CO₃. This work provides a thermal-annealing-free, solution-processable method for fabricating electron-selective layer in inverted PSCs, which should be beneficial for the future development of high performance all-solution-processed or roll-to-roll processed PSCs