Aerosol Release, Distribution and Prevention during Aerosol Therapy: A Simulated Model for Infection Control.

Background: Aerosol therapy is used to deliver medical therapeutics directly to the airways to treat respiratory illnesses. A potential side-effect of this form of treatment is the release of fugitive aerosols into the environment and the exposure of caregivers, other patients, and bystanders to potential viral infections. The aim of this work was to use both flow visualisation and aerosol particle characterisation techniques to study the dispersion, concentrations and size distributions of fugitive aerosols emitted during aerosol therapy delivered via a standard mouthpiece.Methods: Aerosol therapy was delivered via a nebuliser, aerosol holding chamber and mouthpiece to a spontaneously breathing adult patient model that could mimic the release of patient-derived bioaerosol. A combination of laser and Schlieren imaging were used to non-invasively visualise the release and dispersion of fugitive aerosol particles. Time varying aerosol particle number concentrations and size distributions were measured with optical particle sizers at clinically relevant positions. Results: The addition of a capture filter to the expiratory port of the mouthpiece significantly reduced the release and spread of fugitive aerosols. Capture filters were effective in curtailing the release of fugitive aerosols of respirable size, ≤ 5 µm in diameter (P ≤ 0.05). Conclusions: The findings suggest that, where possible, capture filters should be added to the expiratory ports of all aerosol therapy devices to prevent airborne transmission of respiratory illnesses and create safer conditions for healthcare workers and patients.

Herbal medicine derived carbon dots: synthesis and applications in therapeutics, bioimaging and sensing

Since the number of raw material selections for the synthesis of carbon dots (CDs) has grown extensively, herbal medicine as a precursor receives an increasing amount of attention. Compared with other biomass precursors, CDs derived from herbal medicine (HM-CDs) have become the most recent incomer in the family of CDs. In recent ten years, a great many studies have revealed that HM-CDs tend to be good at theranostics without drug loading. However, the relevant development and research results are not systematically reviewed. Herein, the origin and history of HM-CDs are outlined, especially their functional performances in medical diagnosis and treatment. Besides, we sort out the herbal medicine precursors, and analyze the primary synthetic methods and the key characteristics. In terms of the applications of HM-CDs, medical therapeutics, ion and molecular detection, bioimaging, as well as pH sensing are summarized. Finally, we discuss the crucial challenges and future prospects.

The biaxial mechanics of thermally denaturing skin - Part II: Modeling

Understanding the response of skin to superphysiological temperatures is critical to the diagnosis and prognosis of thermal injuries, and to the development of temperature-based medical therapeutics. Unfortunately, this understanding has been hindered by our incomplete knowledge about the nonlinear coupling between skin temperature and its mechanics. In Part I of this study we experimentally demonstrated a complex interdependence of time, temperature, direction, and load in skin's response to superphysiological temperatures. In Part II of our study, we test two different models of skin's thermo-mechanics to explain our observations. In both models we assume that skin's response to superphysiological temperatures is governed by the denaturation of its highly collageneous microstructure. Thus, we capture skin's native mechanics via a microstructurally-motivated strain energy function which includes probability distributions for collagen fiber orientation and waviness. In the first model, we capture skin's response to superphysiological temperatures as a transition between two states that link the kinetics of collagen fiber denaturation to fiber coiling and to the transformation of each fiber's constitutive behavior from purely elastic to viscoelastic. In the second model, we capture skin's response to superphysiological temperatures instead via three states in which a sequence of two reactions link the kinetics of collagen fiber denaturation to fiber coiling, followed by a state of fiber damage. Given the success of both models in qualitatively capturing our observations, we expect that our work will provide guidance for future experiments that could probe each model's assumptions toward a better understanding of skin's coupled thermo-mechanics and that our work will be used to guide the engineering design of heat treatment therapies.

Convalescent plasma, political narrative, and public health ethics in the Covid-19 pandemic

Convalescent plasma therapy emerged as an early experimental therapy for the treatment of Covid-19. However, despite limited data regarding its safety and efficacy, the therapy was extensively publicised by multiple politicians as a cure. We analyse the impact of this political narrative around medical therapeutics on the pandemic using the coherentist model of public health ethics. The clinical benefits of the therapy are evaluated in terms of reduction in mortality and disease progression as compared to the potential transfusion-related adverse events. Political advocacy of therapeutics might hamper the autonomy and decision-making of individuals and institutions. Marketing and monetisation of convalescent plasma might cause inequitable distribution and unregulated use. It also creates an economic burden on the government and healthcare which should be justified by the additional cost/effectiveness ratio of the therapy. This article exemplifies the inadvertent effects and ethical challenges following political narratives about medical therapeutics and the importance of involving ethics in designing policies concerning public healthcare.

The Promise of Aggregation-Induced Emission Luminogens for Detecting COVID-19

The long-term pandemic of coronavirus disease 2019 (COVID-19) requires sensitive and accurate diagnostic assays to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus and SARS-CoV-2 antibodies in infected individuals. Currently, RNA of SARS-CoV-2 virus is mainly detected by reverse transcription-polymerase chain reaction (RT-PCR)-based nucleic acid assays, while SARS-CoV-2 antigen and antibody are identified by immunological assays. Both nucleic acid assays and immunological assays rely on the luminescence signals of specific luminescence probes for qualitative and quantitative detection. The exploration of novel luminescence probes will play a crucial role in improving the detection sensitivity of the assays. As innate probes, aggregation-induced emission (AIE) luminogens (AIEgens) exhibit negligible luminescence in the free state but enhanced luminescence in the aggregated or restricted states. Moreover, AIEgen-based nanoparticles (AIE dots) offer efficient luminescence, good biocompatibility and water solubility, and superior photostability. Both AIEgens and AIE dots have been widely used for high-performance detection of biomolecules and small molecules, chemical/biological imaging, and medical therapeutics. In this review, the availability of AIEgens and AIE dots in nucleic acid assays and immunological assays are enumerated and discussed. By building a bridge between AIE materials and COVID-19, we hope to inspire researchers to use AIE materials as a powerful weapon against COVID-19.

Transcatheter tricuspid valve replacement in patients with severe tricuspid regurgitation

ObjectiveTricuspid regurgitation (TR) is a common valvular heart disease with unsatisfactory medical therapeutics and high surgical mortality. The present study aims to evaluate the safety and effectiveness of transcatheter tricuspid valve replacement (TTVR) in high-risk patients with severe TR.MethodsThis was a compassionate multicentre study. Between September 2018 and November 2019, 46 patients with TR who were not suitable for surgery received compassionate TTVR under general anaesthesia and the guidance of trans-oesophageal echocardiography and fluoroscopy in four institutions. Access to the tricuspid valve was obtained via a minimally invasive thoracotomy and transatrial approach. Patients’ data at baseline, before discharge, 30 days and 6 months after the procedure were collected.ResultsAll patients had severe TR with vena contracta width of 12.6 (11.0, 14.5) mm. Procedural success (97.8%) was achieved in all but one case with right ventricle perforation. The procedural time was 150.0 (118.8, 180.0) min. Intensive care unit time was 2.0 (1.0, 4.0) days. 6-month mortality was 17.4%. Device migration occurred in one patient (2.4%) during follow-up. Transthoracic echocardiography at 6 months after operation showed TR was significantly reduced (none/trivial in 33, mild in 4 and moderate in 1) and the primary safety end point was achieved in 38 cases (82.6%). Patients suffered from peripheral oedema and ascites decreased from 100.0% and 47.8% at baseline to 2.6% and 0.0% at 6 months.ConclusionsThe present study showed TTVR was feasible, safe and with low complication rates in patients with severe TR.