Aerosol Particle Size Influences the Infectious Dose and Disease Severity in a Golden Syrian Hamster Model of Inhalational COVID-19

Background: Significant evidence suggests that SARS-CoV-2 can be transmitted via respiratory aerosols, which are known to vary as a function of respiratory activity. Most animal models examine disease presentation following inhalation of small-particle aerosols similar to those generated during quiet breathing or speaking. However, despite evidence that particle size can influence dose-infectivity relationships and disease presentation for other microorganisms, no studies have examined the infectivity of SARS-CoV-2 contained in larger particle aerosols similar to those produced during coughing, singing, or talking. Therefore, the aim of the present study was to assess the influence of aerodynamic diameter on the infectivity and virulence of aerosols containing SARS-CoV-2 in a hamster model of inhalational COVID-19. Methods: Dose-response relationships were assessed for two different aerosol particle size distributions, with mass median aerodynamic diameters (MMADs) of 1.3 and 5.2 μm in groups of Syrian hamsters exposed to aerosols containing SARS-CoV-2. Results: Disease was characterized by viral shedding in oropharyngeal swabs, increased respiratory rate, decreased activity, and decreased weight gain. Aerosol particle size significantly influenced the median doses to induce seroconversion and viral shedding, with both increasing ∼30-fold when the MMAD was increased. In addition, disease presentation was dose-dependent, with seroconversion and viral shedding occurring at lower doses than symptomatic disease characterized by increased respiratory rate and decreased activity. Conclusions: These results suggest that aerosol particle size may be an important factor influencing the risk of COVID-19 transmission and needs to be considered when developing animal models of disease. This result agrees with numerous previous studies with other microorganisms and animal species, suggesting that it would be generally translatable across different species. However, it should be noted that the absolute magnitude of the observed shifts in the median doses obtained with the specific particle sizes utilized herein may not be directly applicable to other species.

Comparison of Dose-Response Relationships for Two Isolates of SARS-CoV-2 in a Nonhuman Primate Model of Inhalational COVID-19

Background: As the COVID-19 pandemic has progressed, numerous variants of SARS-CoV-2 have arisen, with several displaying increased transmissibility. Methods: The present study compared dose-response relationships and disease presentation in nonhuman primates infected with aerosols containing an isolate of the Gamma variant of SARS-CoV-2 to the results of our previous study with the earlier WA-1 isolate of SARS-CoV-2. Results: Disease in Gamma-infected animals was mild, characterized by dose-dependent fever and oronasal shedding of virus. Differences were observed in shedding in the upper respiratory tract between Gamma- and WA-1-infected animals that have the potential to influence disease transmission. Specifically, the estimated median doses for shedding of viral RNA or infectious virus in nasal swabs were approximately 10-fold lower for the Gamma variant than the WA-1 isolate. Given that the median doses for fever were similar, this suggests that there is a greater difference between the median doses for viral shedding and fever for Gamma than for WA-1 and potentially an increased range of doses for Gamma over which asymptomatic shedding and disease transmission are possible. Conclusions: These results complement those of previous studies, which suggested that differences in exposure dose may help to explain the range of clinical disease presentations observed in individuals with COVID-19, highlighting the importance of public health measures designed to limit exposure dose, such as masking and social distancing. The dose-response data provided by this study are important to inform disease transmission and hazard modeling, as well as to inform dose selection in future studies examining the efficacy of therapeutics and vaccines in animal models of inhalational COVID-19.

Efficacy of pediatric dermatology Extension for Community Healthcare Outcomes (ECHO) sessions on augmenting primary care providers' confidence and abilities

Due to the shortage of pediatric dermatologists and the abundance of skin disorders presenting in childhood, general pediatricians shoulder the management of many pediatric dermatologic disorders and would benefit from additional dermatology-specific training. To address this educational gap, general pediatricians were enrolled in a pediatric dermatology-specific Project Extension for Community Healthcare Outcomes (ECHO) program and surveyed to assess the efficacy of the program in increasing providers' ability and confidence in managing pediatric dermatologic conditions. Providers unanimously reported increased confidence and abilities in assessment and management of pediatric dermatologic conditions. Pediatric dermatology Project ECHO demonstrated high efficacy in improving general practitioners' comfort and knowledge on dermatology-specific topics and may be used as an education model for enhancing primary care providers' knowledge and management of common disorders.

Multi-layer longitudinally specular optics for distributing diffuse light

Multi-layer optical thin films can reflect light to guide it along a hollow tube that they internally line. However, reflecting broadband white light for a range of angles requires many precise thin optical layers, which can be too expensive for large-scale applications such as architectural illumination. Here, we present an alternative configuration that requires only one readily achievable aspect of precision-having a substantially constant cross section, perpendicular to the planned longitudinal propagation direction. This aspect conserves a light ray's longitudinal directional component, while the ray's path in the perpendicular direction can be macroscopically chaotic, much like the diffuse reflection characteristic arising from many non-absorbing pigment particles. This macroscopic characteristic is described here as "longitudinally specular" and "transversely diffuse." This new design overcomes two problems that are found with current prism light guides (PLGs), which are a class of hollow light guides that also have a constant cross section. The PLG has two problems: (1) it requires structured surfaces having near-perfect linear prisms that are much larger than the wavelength of light, wasting optical material and increasing absorption; (2) it only works well with light that has been partially collimated, which limits étendue and requires expensive, inefficient input optics. In this paper, a new, to the best of our knowledge, approach, labeled a "multi-layer prism light guide," simultaneously addresses both problems. Although the new structure is more complex than a conventional PLG, it may be simpler to manufacture. One potential application is for guiding sunlight into buildings for illumination purposes, without requiring complex sun-tracking solar collection optics.

P-P13 Long-term outcome after portal vein resection during pancreaticoduodenectomy for pancreatic ductal adenocarcinoma: a propensity score matched analysis

Background

Portal vein resection (PVR) with pancreaticoduodenectomy (PD) is often performed to achieve clear margins for patients with vascular involvement in pancreatic ductal adenocarcinoma (PDAC). However, there is evidence to suggest that patients undergoing PVR often have more advanced cancers, therefore the impact of PVR on survival and recurrence remains unclear. The aim of this study is to assess overall (OS) and recurrence free (RFS) survival in patients who underwent PVR during PD, with particular attention to margin positivity.

Methods

A retrospective analysis was performed on 638 patients who underwent PD during a 12-year period. Exclusion criteria included PD for non-PDAC tumours, neoadjuvant chemotherapy or intra-operative radiotherapy. 374 patients were included in the study (90 PVR and 284 non-PVR). Patient characteristics and histopathological factors associated with OS and RFS were then evaluated using univariate and multivariate Cox regression analyses. 270 patients (90 PVR and 180 non-PVR), were matched by propensity score based on perineural invasion, pT and pN staging. The Kaplan-Meier method was used to calculate survival and log-rank tests.

Results

Resection margin positivity was associated with shorter OS and RFS (p < 0.0001), and the superior mesenteric vein (SMV) margin was the most significant risk factor for survival on competing risks analysis. Absent adjuvant chemotherapy, nodal metastasis and margin positivity were independent risk factors for OS and RFS on multivariate analysis. PVR was associated with higher intra-operative blood loss (p = 0.009), but was not associated with increased length of stay, complications or readmissions. PVR patients had increased pT staging, nodal metastasis and perineural invasion, however, there was no difference in OS (p = 0.551) or RFS (p = 0.256) between PVR and non-PVR after propensity matching.

Conclusions

Positive resection margins are associated with shorter survival times, and the SMV margin is the most significant prognostic indicator for overall survival and recurrence compared to other margins. PVR is a relatively safe procedure, however, it does not achieve the intended survival benefits of complete margin clearance. The impact on survival for margin positivity, particularly the SMV margin, and nodal metastasis should be considered when making decisions with regards to vein resection and adjuvant treatments.

Seroconversion and fever are dose-dependent in a nonhuman primate model of inhalational COVID-19

While evidence exists supporting the potential for aerosol transmission of SARS-CoV-2, the infectious dose by inhalation remains unknown. In the present study, the probability of infection following inhalation of SARS-CoV-2 was dose-dependent in a nonhuman primate model of inhalational COVID-19. The median infectious dose, assessed by seroconversion, was 52 TCID50 (95% CI: 23-363 TCID50), and was significantly lower than the median dose for fever (256 TCID50, 95% CI: 102-603 TCID50), resulting in a group of animals that developed an immune response post-exposure but did not develop fever or other clinical signs of infection. In a subset of these animals, virus was detected in nasopharyngeal and/or oropharyngeal swabs, suggesting that infected animals without signs of disease are able to shed virus and may be infectious, which is consistent with reports of asymptomatic spread in human cases of COVID-19. These results suggest that differences in exposure dose may be a factor influencing disease presentation in humans, and reinforce the importance of public health measures that limit exposure dose, such as social distancing, masking, and increased ventilation. The dose-response data provided by this study are important to inform disease transmission and hazard modeling, and, ultimately, mitigation strategies. Additionally, these data will be useful to inform dose selection in future studies examining the efficacy of therapeutics and vaccines against inhalational COVID-19, and as a baseline in healthy, young adult animals for assessment of the importance of other factors, such as age, comorbidities, and viral variant, on the infectious dose and disease presentation.

Comparison of the performance of aerosol sampling devices for measuring infectious SARS-CoV-2 aerosols

To assess the risk of aerosol transmission of SARS-CoV-2, measurements of the airborne viral concentrations in proximity to infected individuals, the persistence of the virus in aerosols, and the dose of the virus needed to cause infection following inhalation are required. For studies aimed at quantifying these parameters, an aerosol sampling device needs to be employed. A number of recent studies have reported the detection of both genetic material and infectious SARS-CoV-2 virus in air samples collected in clinical settings. Previous studies have demonstrated that the efficiency of different samplers for collection and preservation of the infectivity of microorganisms can vary as a function of the specific microorganism. In the present study, the performance of eight common low-flow aerosol sampling devices were compared for their ability to collect and preserve the infectivity of airborne SARS-CoV-2 contained in small particle aerosols. The influence of sampling duration on recovery of infectious virus was also evaluated. Similar concentrations of infectious SARS-CoV-2 were measured in aerosols for the majority of the samplers tested, with the exception of the midget impingers, which measured significantly lower concentrations of SARS-CoV-2. Additionally, in three of the four impingers tested, additional clean airflow through the device following collection of infectious virus resulted in a decrease of the infectious concentration of virus over time, suggesting that virus was being inactivated and these devices may not be suitable for sampling for long durations. Further, RNA copies in the samples over time did not correspond with the losses of infectious SARS-CoV-2 observed in the impingers samples. These data can be utilized to inform interpretation of current studies on the SARS-CoV-2 viral loads in air samples, as well as inform sampling device selection in future studies.

Cell wall protein variation, break-induced replication, and subtelomere dynamics in Candida glabrata

Candida glabrata is an opportunistic pathogen of humans, responsible for up to 30% of disseminated candidiasis. Adherence of C. glabrata to host cells is mediated by adhesin-like proteins (ALPs), about half of which are encoded in the subtelomeres. We performed a de novo assembly of two C. glabrata strains, BG2 and BG3993, using long single-molecule real-time (SMRT) reads, and constructed high-quality telomere-to-telomere assemblies of all 13 chromosomes to assess differences between C. glabrata strains. We documented variation between strains, and in agreement with earlier studies, found high (~0.5%-1%) frequencies of SNVs across the genome, including within subtelomeric regions. We documented changes in ALP gene structure and complement: there are large length differences in ALP genes in different strains, resulting from copy number variation in tandem repeats. We compared strains to characterize chromosome rearrangement events including within the poorly characterized subtelomeric regions. We show that rearrangements within the subtelomere regions all affect ALP-encoding genes, and 14/16 involve just the most terminal ALP gene. We present evidence that these rearrangements are mediated by break-induced replication. This study highlights the constrained nature of subtelomeric changes impacting ALP gene complement and subtelomere structure.

Airborne SARS-CoV-2 Is Rapidly Inactivated by Simulated Sunlight

Aerosols represent a potential transmission route of COVID-19. This study examined effect of simulated sunlight, relative humidity, and suspension matrix on stability of SARS-CoV-2 in aerosols. Simulated sunlight and matrix significantly affected decay rate of the virus. Relative humidity alone did not affect the decay rate; however, minor interactions between relative humidity and other factors were observed. Mean decay rates (± SD) in simulated saliva, under simulated sunlight levels representative of late winter/early fall and summer were 0.121 ± 0.017 min-1 (90% loss, 19 minutes) and 0.306 ± 0.097 min-1 (90% loss, 8 minutes), respectively. Mean decay rate without simulated sunlight across all relative humidity levels was 0.008 ± 0.011 min-1 (90% loss, 286 minutes). These results suggest that the potential for aerosol transmission of SARS-CoV-2 may be dependent on environmental conditions, particularly sunlight. These data may be useful to inform mitigation strategies to minimize the potential for aerosol transmission.

Airborne SARS-CoV-2 Is Rapidly Inactivated by Simulated Sunlight

Aerosols represent a potential transmission route of COVID-19. This study examined effect of simulated sunlight, relative humidity, and suspension matrix on stability of SARS-CoV-2 in aerosols. Simulated sunlight and matrix significantly affected decay rate of the virus. Relative humidity alone did not affect the decay rate; however, minor interactions between relative humidity and other factors were observed. Mean decay rates (± SD) in simulated saliva, under simulated sunlight levels representative of late winter/early fall and summer were 0.121 ± 0.017 min-1 (90% loss, 19 minutes) and 0.306 ± 0.097 min-1 (90% loss, 8 minutes), respectively. Mean decay rate without simulated sunlight across all relative humidity levels was 0.008 ± 0.011 min-1 (90% loss, 286 minutes). These results suggest that the potential for aerosol transmission of SARS-CoV-2 may be dependent on environmental conditions, particularly sunlight. These data may be useful to inform mitigation strategies to minimize the potential for aerosol transmission.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Simulated Sunlight Rapidly Inactivates SARS-CoV-2 on Surfaces

Previous studies have demonstrated that SARS-CoV-2 is stable on surfaces for extended periods under indoor conditions. In the present study, simulated sunlight rapidly inactivated SARS-CoV-2 suspended in either simulated saliva or culture media and dried on stainless steel coupons. Ninety percent of infectious virus was inactivated every 6.8 minutes in simulated saliva and every 14.3 minutes in culture media when exposed to simulated sunlight representative of the summer solstice at 40°N latitude at sea level on a clear day. Significant inactivation also occurred, albeit at a slower rate, under lower simulated sunlight levels. The present study provides the first evidence that sunlight may rapidly inactivate SARS-CoV-2 on surfaces, suggesting that persistence, and subsequently exposure risk, may vary significantly between indoor and outdoor environments. Additionally, these data indicate that natural sunlight may be effective as a disinfectant for contaminated nonporous materials.

Pulse- and field-resolved THz-diagnostics at 4 t h generation lightsources

Multi-color pump-probe techniques utilizing modern accelerator-based 4th generation light sources such as X-ray free electron lasers or superradiant THz facilities have become important science drivers over the past 10 years. In this type of experiments the precise knowledge of the properties of the involved accelerator-based light pulses crucially determines the achievable sensitivity and temporal resolution. In this work we demonstrate and discuss the powerful role pulse- and field-resolved- detection of superradiant THz pulses can play for improving the precision of THz pump - femtosecond laser probe experiments at superradiant THz facilities in particular and at 4th generation light sources in general. The developed diagnostic scheme provides real-time information on the properties of individual pulses from multiple accelerator based THz sources and opens a robust way for sub femtosecond timing. Correlations between amplitude and phase of the pulses emitted from different superradiant THz sources furthermore provide insides into the properties of the driving electron bunches and is of general interest for the ultra-fast diagnostics at 4th generation light sources.

Bullous systemic lupus erythematosus successfully treated with rituximab

Bullous systemic lupus erythematosus (BSLE) is a rare complication of systemic lupus erythematosus (SLE) characterized by cutaneous vesicles and bullae with a primarily neutrophilic infiltrate on histopathology. Bullous SLE is a heterogeneous disease without pathognomonic clinical features, making the diagnosis and differentiation from other blistering diseases challenging. We present the case of a single patient with SLE in whom 3 different clinical appearances of BSLE manifested over 5 years. The cutaneous eruption dramatically improved with rituximab at the initial presentation and continued to respond to rituximab during subsequent flares over the subsequent 5 years.

Clinical relevance of non-tuberculous mycobacteria isolated from respiratory specimens: seven year experience in a UK hospital

The frequency of isolation of non-tuberculous mycobacteria (NTM) species from respiratory specimens is increasing, however the clinical relevance of such identifications vary by mycobacterial species and geographical location. A retrospective study of 853 NTM isolates from respiratory samples from 386 patients over seven years was performed. Clinical records and radiographic information were examined. Clinical significance was assessed by American Thoracic Society diagnostic criteria. 25% of all patients with respiratory isolates met criteria for non-tuberculous mycobacterial pulmonary disease (NTM-PD). Significant symptoms were weight loss, fever, night sweats, productive cough and haemoptysis. HIV co-infection was a significant risk factor for disease. Cavities, nodules and tree-in-bud were significant radiographic findings. Mycobacterium avium complex (MAC) were the dominant species isolated from this patient cohort. Mycobacterium abscessus (M. abscessus) was the species most likely to cause clinically significant disease and be sputum smear positive, thus warranting particular attention.

On-chip THz spectrometer for bunch compression fingerprinting at fourth-generation light sources

The layout of an integrated millimetre-scale on-chip THz spectrometer is presented and its peformance demonstrated. The device is based on eight Schottky-diode detectors which are combined with narrowband THz antennas, thereby enabling the simultaneous detection of eight frequencies in the THz range on one chip. The size of the active detector area matches the focal spot size of superradiant THz radiation utilized in bunch compression monitors of modern linear electron accelerators. The 3 dB bandwidth of the on-chip Schottky-diode detectors is less than 10% of the center frequency and allows pulse-resolved detection at up to 5 GHz repetition rates. The performance of a first prototype device is demonstrated at a repetition rate of 100 kHz at the quasi-cw SRF linear accelerator ELBE operated with electron bunch charges between a few pC and 100 pC.

Comparative Pathogenesis of Asian and African-Lineage Zika Virus in Indian Rhesus Macaque's and Development of a Non-Human Primate Model Suitable for the Evaluation of New Drugs and Vaccines

The establishment of a well characterized non-human primate model of Zika virus (ZIKV) infection is critical for the development of medical interventions. In this study, challenging Indian rhesus macaques (IRMs) with ZIKV strains of the Asian lineage resulted in dose-dependent peak viral loads between days 2 and 5 post infection and a robust immune response which protected the animals from homologous and heterologous re-challenge. In contrast, viremia in IRMs challenged with an African lineage strain was below the assay’s lower limit of quantitation, and the immune response was insufficient to protect from re-challenge. These results corroborate previous observations but are contrary to reports using other African strains, obviating the need for additional studies to elucidate the variables contributing to the disparities. Nonetheless, the utility of an Asian lineage ZIKV IRM model for countermeasure development was verified by vaccinating animals with a formalin inactivated reference vaccine and demonstrating sterilizing immunity against a subsequent subcutaneous challenge.

Towards femtosecond-level intrinsic laser synchronization at fourth generation light sources

In this Letter, the proof of principle for a scheme providing intrinsic femtosecond-level synchronization between an external laser system and fourth generation light sources is presented. The scheme is applicable at any accelerator-based light source that is based on the generation of coherent radiation from ultrashort electron bunches such as superradiant terahertz (THz) facilities or X-FELs. It makes use of a superradiant THz pulse generated by the accelerator as an intrinsically synchronized gate signal for electro-optical slicing. We demonstrate that the scheme enables a reduction of the timing instability by more than 2 orders of magnitude. This demonstration experiment thereby proves that intrinsically synchronized time-resolved experiments utilizing laser and accelerator-based radiation pulses on few tens of femtosecond (fs) to few fs timescales are feasible.

Determination of Plasma Concentration Reference Ranges for Risperidone and Paliperidone

Schizophrenia is a common disease managed by a range of interventions, with the primary treatment being antipsychotic medications (APS). Inadequate response, lack of adherence, and/or adverse events often prevent optimal therapeutic effects or therapeutic efficiency. Monitoring APS plasma concentrations can be used together with a full clinical evaluation to help improve patient care or offer better treatment options for the patient. To enable interpretation of individual risperidone and paliperidone plasma concentrations, we developed "reference ranges," which consider the expected variability in plasma concentrations between subjects across the population, rather than representing a "therapeutic range" that relates to efficacy and/or safety outcomes. The reference ranges were derived from population pharmacokinetic models, which varied based upon administration route, dose, and time after dose. Good agreement between the proposed reference ranges and external data was obtained through graphical and numerical evaluations, indicating they could be reliably used in clinical practice.

Analysis of Affordance, Time, and Adaptation in the Assessment of Industrial Control System Cybersecurity Risk

Industrial control systems increasingly use standard communication protocols and are increasingly connected to public networks-creating substantial cybersecurity risks, especially when used in critical infrastructures such as electricity and water distribution systems. Methods of assessing risk in such systems have recognized for some time the way in which the strategies of potential adversaries and risk managers interact in defining the risk to which such systems are exposed. But it is also important to consider the adaptations of the systems' operators and other legitimate users to risk controls, adaptations that often appear to undermine these controls, or shift the risk from one part of a system to another. Unlike the case with adversarial risk analysis, the adaptations of system users are typically orthogonal to the objective of minimizing or maximizing risk in the system. We argue that this need to analyze potential adaptations to risk controls is true for risk problems more generally, and we develop a framework for incorporating such adaptations into an assessment process. The method is based on the principle of affordances, and we show how this can be incorporated in an iterative procedure based on raising the minimum period of risk materialization above some threshold. We apply the method in a case study of a small European utility provider and discuss the observations arising from this.

Chronic effects of an invasive species on an animal community

Invasive species can trigger trophic cascades in animal communities, but published cases involving their removal of top predators are extremely rare. An exception is the invasive cane toad (Rhinella marina) in Australia, which has caused severe population declines in monitor lizards, triggering trophic cascades that facilitated dramatic and sometimes unexpected increases in several prey of the predators, including smaller lizards, snakes, turtles, crocodiles, and birds. Persistence of isolated populations of these predators with a decades-long sympatry with toads suggests the possibility of recovery, but alternative explanations are possible. Confirming predator recovery requires longer-term study of populations with both baseline and immediate post-invasion densities. Previously, we quantified short-term impacts of invasive cane toads on animal communities over seven years at two sites in tropical Australia. Herein, we test the hypothesis that predators have begun to recover by repeating the study 12 yr after the initial toad invasion. The three predatory lizards that experienced 71-97% declines in the short-term study showed no sign of recovery, and indeed a worse fate: two of the three species were no longer detectable in 630 km of river surveys, suggesting local extirpation. Two mesopredators that had increased markedly in the short term due to these predator losses showed diverse responses in the medium term; a small lizard species increased by ~500%, while populations of a snake species showed little change. Our results indicate a system still in ecological turmoil, having not yet reached a "new equilibrium" more than a decade after the initial invasion; predator losses due to this toxic invasive species, and thus downstream effects, were not transient. Given that cane toads have proven too prolific to eradicate or control, we suggest that recovery of impacted predators must occur unassisted by evolutionary means: dispersal into extinction sites from surviving populations with alleles for toxin resistance or toad avoidance. Evolution and subsequent dispersal may be the only solution for a number of species or communities affected by invasive species for which control is either prohibitively expensive, or not possible.

Optimizing Antipsychotic Patient Management Using Population Pharmacokinetic Models and Point-of-Care Testing

Schizophrenia is a common disease, characterized by progressive functional decline exacerbated by psychotic relapses that often result from a lack of full adherence to antipsychotic (APS) medication. Although atypical APS medications do not have clear therapeutic windows, as generally required for therapeutic drug monitoring (TDM), measuring APS plasma levels in the context of a population expected range at the point‐of‐care (POC) may provide valuable clinical insights for differentiating lack of efficacy from a lack of adherence to medication.

Challenging hierarchy in healthcare teams - ways to flatten gradients to improve teamwork and patient care

In healthcare, mistakes that are potentially harmful or fatal to patients are often the result of poor communication between members of a team. This is particularly important in high-risk areas such as operating theatres or during any intervention, and the ability to challenge colleagues who are in authority when something does not seem right or is clearly wrong, is crucial. Colleagues in oral and maxillofacial surgery recognised the importance of this as early as 2004, and it is now well known that failure or reluctance to challenge others who might be wrong can severely compromise a patient's safety. The Royal College of Surgeons of Edinburgh runs popular regular courses (Non-technical Skills for Surgeons, NOTSS) that teach how to ensure safety through good communication and teamwork. In this paper we introduce the concept of hierarchical challenge, and discuss models and approaches to address situations when problems arise within a team.

Probing ultra-fast processes with high dynamic range at 4th-generation light sources: Arrival time and intensity binning at unprecedented repetition rates

Understanding dynamics on ultrafast timescales enables unique and new insights into important processes in the materials and life sciences. In this respect, the fundamental pump-probe approach based on ultra-short photon pulses aims at the creation of stroboscopic movies. Performing such experiments at one of the many recently established accelerator-based 4th-generation light sources such as free-electron lasers or superradiant THz sources allows an enormous widening of the accessible parameter space for the excitation and/or probing light pulses. Compared to table-top devices, critical issues of this type of experiment are fluctuations of the timing between the accelerator and external laser systems and intensity instabilities of the accelerator-based photon sources. Existing solutions have so far been only demonstrated at low repetition rates and/or achieved a limited dynamic range in comparison to table-top experiments, while the 4th generation of accelerator-based light sources is based on superconducting radio-frequency technology, which enables operation at MHz or even GHz repetition rates. In this article, we present the successful demonstration of ultra-fast accelerator-laser pump-probe experiments performed at an unprecedentedly high repetition rate in the few-hundred-kHz regime and with a currently achievable optimal time resolution of 13 fs (rms). Our scheme, based on the pulse-resolved detection of multiple beam parameters relevant for the experiment, allows us to achieve an excellent sensitivity in real-world ultra-fast experiments, as demonstrated for the example of THz-field-driven coherent spin precession.

Controlled and Sequential Delivery of Fluorophores from 3D Printed Alginate-PLGA Tubes

Controlled drug delivery systems, that include sequential and/or sustained drug delivery, have been utilized to enhance the therapeutic effects of many current drugs by effectively delivering drugs in a time-dependent and repeatable manner. In this study, with the aid of 3D printing technology, a novel drug delivery device was fabricated and tested to evaluate sequential delivery functionality. With an alginate shell and a poly(lactic-co-glycolic acid) (PLGA) core, the fabricated tubes displayed sequential release of distinct fluorescent dyes and showed no cytotoxicity when incubated with the human embryonic kidney (HEK293) cell line or bone marrow stromal stem cells (BMSC). The controlled differential release of drugs or proteins through such a delivery system has the potential to be used in a wide variety of biomedical applications from treating cancer to regenerative medicine.

A regional EUS service using a collaborative network

Endoscopic ultrasound (EUS) is increasingly used in the management of hepatobiliary lesions, allowing staging and tissue acquisition. It is operator-dependent, and fine needle aspiration (FNA) of solid lesions provides an auditable standard; high-volume centres have shown excellent results for solid pancreatic lesion FNA with sensitivities of 92%-97%. The British Society of Gastroenterology guidelines stress that clinical quality should determine service provision, with geographical accessibility a secondary consideration. We set up the Wessex EUS network, working from a single hepatobiliary (HPB) pancreatic multidisciplinary team, with EUS provided in four local centres providing agreed standards and audit. Pancreatic solid lesion FNA results showed a pooled sensitivity of 94%, comparable with high-volume single centres. This demonstrates a network with good clinical governance is a plausible solution to providing a specialist service such as EUS and may be a roadmap that other specialist services under pressure could follow.

Information technology in nurse education: a multimedia approach to teaching biological sciences

The School of Health Science at the University of Wales Swansea offers programmes for nurses and other healthcare professionals ranging from pre-registration nursing to post-doctoral studies. Biological science is an important component of the pre-registration programme, the delivery of which has proved to be problematic. Research conducted by the school has identified that a more innovative approach to teaching and learning this subject is required.

There is a growing body of evidence that Multimedia Learning (MML) can enhance the quality of education, supporting or replacing the traditional didactic lecture and providing the student with information and standards of presentation that have never before been available. With this in mind, and responding to the research findings, the school has made a substantial investment in multimedia technology. We have now embarked on a programme to produce and deliver a biological science module for nursing students. If the evaluation of the programme demonstrates sustainable improvements in learning and offers enhanced quality in the delivery of programmes, it is the intention to extrapolate the biological science project to other curriculum subjects.

An update on the latest evidence for managing the clinically negative neck (cN0) in oral squamous cell carcinoma

The single most important prognostic indicator for survival in oral squamous cell carcinoma (OSCC) is the presence of lymph node metastases in the neck. While the treatment of the clinically node positive (cN+) neck is well established, the management of the clinically negative neck (cN0) is controversial. Various strategies have been advocated including close observation including regular ultrasound imaging, elective neck dissection and sentinel lymph node biopsy. Neck dissection surgery is not without potential morbidity with shoulder dysfunction being the main complication. A number of factors are associated with increased risk of neck node metastasis including primary tumour thickness and peri-neural invasion. A recent prospective randomised trial has found survival benefit following neck dissection even in patients with a cN0 neck at presentation. We discuss the latest evidence for managing the cN0 in OSCC and include our own experience on the role of neck dissection in certain cases.

Sentinel lymph node biopsy for head and neck mucosal cancers - an update on the current evidence

Regional metastases are a prominent feature of mucosal-associated head and neck squamous cell carcinomas and are an important prognostic factor. Sentinel lymph node biopsy (SLNB) is one modality that has potential to add to the accuracy of neck staging, although it is currently not used as widely in the head and neck as it is in other areas such as breast cancer. We review the efficacy of SLNB in head and neck mucosal squamous cell carcinomas and provide an overview of current practice and include details of technical advances.