Measurement of Fluorescence in a Rhodamine-123 Doped Self-Assembled “Giant” Mesostructured Silica Sphere Using a Smartphone as Optical Hardware

The blue OLED emission from a mobile phone was characterised, revealing a sharp emission band centred at λ = 445 nm with a 3dB bandwidth Δλ ∼ 20 nm. It was used to excite Rhodamine 123 doped within a “giant” mesostructured silica sphere during fabrication through evaporative self-assembly of silica nanoparticles. Fluorescence was able to be detected using a standard optical microscope fitted with a green transmission pass filter and cooled CCD and with 1 ms exposure time demonstrating the potential of mobile platforms as the basis for portable diagnostics in the field

Improved peroxide biosensor based on Horseradish Peroxidase/Carbon Nanotube on a thiol-modified gold electrode

A new 3-dimensional (3D) network of crosslinked Horseradish Peroxidase/Carbon Nanotube (HRP/CNT) on a thiol-modified Au surface has been described in order to build up the effective electrical wiring of the enzyme units with the electrode. The synthesized 3D HRP/CNT network has been characterized with cyclic voltammetry and amperometry which results the establishment of direct electron transfer between the redox active unit of HRP and the Au surface. Electrochemical measurements reveal that the high biological activity and stability is exhibited by the immobilized HRP and a quasi-reversible redox peak of the redox centre of HRP was observed at about −0.355 and −0.275 V vs. Ag/AgCl. The electron transfer rate constant, KS and electron transfer co-efficient α were found as 0.57 s−1 and 0.42, respectively. Excellent electrocatalytic activity for the reduction of H2O2 was exhibited by the developed biosensor. The proposed biosensor modified with HRP/CNT 3D network displays a broader linear range and a lower detection limit for H2O2 determination. The linear range is from 1.0 × 10−7 to 1.2 × 10−4 M with a detection limit of 2.2.0 × 10−8 M at 3 σ. The Michaelies–Menten constant Kapp M value is estimated to be 0.19 mM. Moreover, this biosensor exhibits very high sensitivity, good reproducibility and long-time stability

Perioperative complications among head and neck surgery patients with COVID-19

Background: Patients undergoing surgery for head and neck cancer (HNC) have potentially high perioperative complication rates. Recent studies indicate that preoperative COVID-19 infection poses increased risk for postoperative complications in other fields. However, to date, there has not been data showing the effect of COVID-19 on complication rates for HNC. Here, a large database was employed to assess if perioperative COVID-19 increased the risk of perioperative complications among those undergoing HNC surgery. Methods: A retrospective investigation was conducted using a multi-institutional research database. Subjects who underwent HNC surgery from January 2020 to September 2022 were identified using the International Classification of Diseases and Current Procedure Terminology codes. Thirty-day surgical and medical complications were assessed for those diagnosed with COVID-19 infection from 7 days before or after surgery compared to those who were COVID-19 negative. Cohorts were propensity scores matched by age, sex, and race. Results: Perioperative COVID-19 was present in n = 208 and absent in n = 15 158 subjects that underwent HNC surgery. For unmatched analyses, there was a statistically significant increased risk in the 30-day postoperative period in COVID-19-positive patients for the following surgical complications: surgical site fistula, free tissue transfer (FTT) complication, FTT failure, and death. Additionally, there was a statistically significant increased risk in the 30-day postoperative period in COVID-19-positive patients for the following medical complications: ventilator support, pneumonia, vasopressor, acute renal failure, and myocardial infarction. Conclusion: This large, retrospective populational study suggests HNC patients are at increased risk for death and several perioperative complications. This investigation is the first to address this clinical question

Increased upconversion performance for thin film solar cells: A trimolecular composition

Photochemical upconversion based on triplet-triplet annihilation (TTA-UC) is employed to enhance the short-circuit currents generated by two varieties of thin-film solar cells, a hydrogenated amorphous silicon (a-Si:H) solar cell and a dye-sensitized solar cell (DSC). TTA-UC is exploited to harvest transmitted sub-bandgap photons, combine their energies and re-radiate upconverted photons back towards the solar cells. In the present study we employ a dual-emitter TTA-UC system which allows for significantly improved UC quantum yields as compared to the previously used single-emitter TTA systems. In doing so we achieve record photo-current enhancement values for both the a-Si:H device and the DSC, surpassing 10-3 mA cm-2 sun-2 for the first time for a TTA-UC system and marking a record for upconversion-enhanced solar cells in general. We discuss pertinent challenges of the TTA-UC technology which need to be addressed in order to achieve its viable device application

Improving the light-harvesting of amorphous silicon solar cells with photochemical upconversion

Single-threshold solar cells are fundamentally limited by their ability to harvest only those photons above a certain energy. Harvesting below-threshold photons and re-radiating this energy at a shorter wavelength would thus boost the efficiency of such devices. We report an increase in light harvesting efficiency of a hydrogenated amorphous silicon (a-Si:H) thin-film solar cell due to a rear upconvertor based on sensitized triplet–triplet-annihilation in organic molecules. Low energy light in the range 600–750 nm is converted to 550–600 nm light due to the incoherent photochemical process. A peak efficiency enhancement of (1.0 ± 0.2)% at 720 nm is measured under irradiation equivalent to (48 ± 3) suns (AM1.5). We discuss the pathways to be explored in adapting photochemical UC for application in various single threshold devices

Effect of a back reflector

Photochemical upconversion is applied to a hydrogenated amorphous silicon solar cell in the presence of a back-scattering layer. A custom-synthesized porphyrin was utilized as the sensitizer species, with rubrene as the emitter. Under a bias of 24 suns, a peak external quantum efficiency (EQE) enhancement of ~2 % was observed at a wavelength of 720 nm. Without the scattering layer, the EQE enhancement was half this value, indicating that the effect of the back-scatterer is to double the efficacy of the upconverting device. The results represent an upconversion figure of merit of 3.5 × 10–4 mA cm–2 sun–2, which is the highest reported to date

Morality tales: young women's narratives on offending, self-worth and desistance

This article emerges from a study of female offenders’ participation in police-facilitated restorative justice in one county in England. The qualitative study, presented here, is based on life history interviews with twelve women and focuses on three morality tales that emerged through narrative analysis: ‘offending as play,’ ‘the strong woman’ and ‘work and a normal life.’ The women used these tales to protect self-worth and justify ‘bad’ behavior in order to counter professional responses which they viewed as stigmatising. The paper concludes with implications for practice with girls and women who offend, which may benefit police, probation and social workers