Liberal or Restrictive Transfusion Strategy in Patients with Traumatic Brain Injury.

BACKGROUND: The effect of a liberal transfusion strategy as compared with a restrictive strategy on outcomes in critically ill patients with traumatic brain injury is unclear. METHODS: We randomly assigned adults with moderate or severe traumatic brain injury and anemia to receive transfusion of red cells according to a liberal strategy (transfusions initiated at a hemoglobin level of ≤10 g per deciliter) or a restrictive strategy (transfusions initiated at ≤7 g per deciliter). The primary outcome was an unfavorable outcome as assessed by the score on the Glasgow Outcome Scale-Extended at 6 months, which we categorized with the use of a sliding dichotomy that was based on the prognosis of each patient at baseline. Secondary outcomes included mortality, functional independence, quality of life, and depression at 6 months. RESULTS: A total of 742 patients underwent randomization, with 371 assigned to each group. The analysis of the primary outcome included 722 patients. The median hemoglobin level in the intensive care unit was 10.8 g per deciliter in the group assigned to the liberal strategy and 8.8 g per deciliter in the group assigned to the restrictive strategy. An unfavorable outcome occurred in 249 of 364 patients (68.4%) in the liberal-strategy group and in 263 of 358 (73.5%) in the restrictive-strategy group (adjusted absolute difference, restrictive strategy vs. liberal strategy, 5.4 percentage points; 95% confidence interval, -2.9 to 13.7). Among survivors, a liberal strategy was associated with higher scores on some but not all the scales assessing functional independence and quality of life. No association was observed between the transfusion strategy and mortality or depression. Venous thromboembolic events occurred in 8.4% of the patients in each group, and acute respiratory distress syndrome occurred in 3.3% and 0.8% of patients in the liberal-strategy and restrictive-strategy groups, respectively. CONCLUSIONS: In critically ill patients with traumatic brain injury and anemia, a liberal transfusion strategy did not reduce the risk of an unfavorable neurologic outcome at 6 months. (Funded by the Canadian Institutes of Health Research and others; HEMOTION ClinicalTrials.gov number, NCT03260478.).

Performance on the mouse vibration actuating search task is compromised by sleep deprivation.

As we go about our daily routines we are continuously bombarded with environmental feedback that requires appraisal and response. Sleep loss can compromise the efficiency by which these cognitive processes function. Operationally, poor performance caused by insufficient sleep translates to increased health and safety risks in settings where attention and timely and/or accurate decisions to respond are critical (e.g., at work, on the road, etc.). Current rodent tasks that assess altered cognition after sleep deprivation (SD) do not accurately model the continuous multisensory feedback that informs goal-oriented behavior in humans. Herein, we describe the vibration actuating search task (VAST), which consists of a vibrating open field with pseudo-randomly selected entrance and target destination points. To successfully complete a trial, mice use feedback from rotary motor-induced floor vibrations to navigate from the entrance point to the target destination. Sets of 20 trials were conducted on 3 consecutive days, and before testing on the third day control mice were undisturbed while other mice were sleep deprived for 10 h. On the first 2 days mice learned the task with high success rates. Alternatively, VAST performance was compromised following SD as measured by increased failures in task completion, time to target, time spent immobile, and decreased speed as compared with undisturbed mice. The VAST enables the analysis of continuous feedback via multiple sensory modalities in mice and is applicable to a variety of operational settings.NEW & NOTEWORTHY The vibration actuating search task (VAST) is a novel performance assay that uses continuous auditory and haptic feedback to motivate and direct search behaviors in mice. The VAST is rapidly acquired by mice and performance is disrupted by sleep deprivation. The VAST has practical application in occupational settings. The cognitive aspects of the sensorimotor integration in the VAST may prove useful for rodent models of neurodegenerative disease.

Definition of hourly urine output influences reported incidence and staging of acute kidney injury.

BACKGROUND: Acute kidney injury (AKI) is commonly defined using the KDIGO system, which includes criteria based on reduced urine output (UO). There is no consensus on whether UO should be measured using consecutive hourly readings or mean output. This makes KDIGO UO definition and staging of AKI vulnerable to inconsistency which has implications both for research and clinical practice. The objective of this study was to investigate whether the way in which UO is defined affects incidence and staging of AKI. METHODS: We conducted a retrospective analysis of two single centre observational studies investigating (i) patients undergoing cardiac surgery and (ii) patients admitted to general intensive care units (ICU). AKI was identified using KDIGO serum creatinine (SCr) criteria and two methods of UO (UOcons: UO meeting KDIGO criteria in each consecutive hour; UOmean: mean hourly UO meeting KDIGO criteria). RESULTS: Data from 151 CICU and 150 ICU admissions were analysed. Incidence of AKI using SCr alone was 23.8% in CICU and 32% in ICU. Incidence increased in both groups when UO was considered, with inclusion of UOmean more than doubling reported incidence of AKI (CICU: UOcons 39.7%, UOmean 72.8%; ICU: UOcons 51.3%, UOmean 69.3%). In both groups UOcons led to a larger increase in KDIGO stage 1 but UOmean increased the incidence of KDIGO stage 2. CONCLUSIONS: We demonstrate a serious lack of clarity in the internationally accepted AKI definition leading to significant variability in reporting of AKI incidence.

The practice of glycaemic control in intensive care units: A multicentre survey of nursing and medical professionals.

AIMS AND OBJECTIVES: To determine the views of nurses and physicians working in intensive care units (ICU) about the aims of glycaemic control and use of their protocols. BACKGROUND: Evidence about the optimal aims and methods for glycaemic control in ICU is controversial, and current local protocols guiding practice differ between ICUs, both nationally and internationally. The views of professionals on glycaemic control can influence their practice. DESIGN: Cross-sectional, multicentre, survey-based study. METHODS: An online short survey was sent to all physicians and nurses of seven ICUs, including questions on effective glycaemic control, treatment of hypoglycaemia and deviations from protocols' instructions. STROBE reporting guidelines were followed. RESULTS: Over half of the 40 respondents opined that a patient spending <75% admission time within the target glycaemic levels constituted poor glycaemic control. Professionals with more than 5 years of experience were more likely to rate a patient spending 50%-74% admission time within target glycaemic levels as poor than less experienced colleagues. Physicians were more likely to rate a patient spending <50% admission time within target as poor than nurses. There was general agreement on how professionals would rate most deviations from their protocols. Nurses were more likely to rate insulin infusions restarted late and incorrect dosage of rescue glucose as major deviations than physicians. Most professionals agreed on when they would treat hypoglycaemia. CONCLUSIONS: When surveyed on various aspects of glycaemic control, ICU nurses and physicians often agreed, although there were certain areas of disagreement, in which their profession and level of experience seemed to play a role. RELEVANCE TO CLINICAL PRACTICE: Differing views on glycaemic control amongst professionals may affect their practice and, thus, could lead to health inequalities. Clinical leads and the multidisciplinary ICU team should assess and, if necessary, address these differing opinions.

Chaste: an open source C++ library for computational physiology and biology.

Chaste - Cancer, Heart And Soft Tissue Environment - is an open source C++ library for the computational simulation of mathematical models developed for physiology and biology. Code development has been driven by two initial applications: cardiac electrophysiology and cancer development. A large number of cardiac electrophysiology studies have been enabled and performed, including high-performance computational investigations of defibrillation on realistic human cardiac geometries. New models for the initiation and growth of tumours have been developed. In particular, cell-based simulations have provided novel insight into the role of stem cells in the colorectal crypt. Chaste is constantly evolving and is now being applied to a far wider range of problems. The code provides modules for handling common scientific computing components, such as meshes and solvers for ordinary and partial differential equations (ODEs/PDEs). Re-use of these components avoids the need for researchers to 're-invent the wheel' with each new project, accelerating the rate of progress in new applications. Chaste is developed using industrially-derived techniques, in particular test-driven development, to ensure code quality, re-use and reliability. In this article we provide examples that illustrate the types of problems Chaste can be used to solve, which can be run on a desktop computer. We highlight some scientific studies that have used or are using Chaste, and the insights they have provided. The source code, both for specific releases and the development version, is available to download under an open source Berkeley Software Distribution (BSD) licence at http://www.cs.ox.ac.uk/chaste, together with details of a mailing list and links to documentation and tutorials.

Corrigendum: Image discrimination reversal learning is impaired by sleep deprivation in rats: Cognitive rigidity or fatigue?

[This corrects the article DOI: 10.3389/fnsys.2022.1052441.].

Laser Derived Electron Transport Layers with Embedded p-n Heterointerfaces Enabling Planar Perovskite Solar Cells with Efficiency over 25.

Electron transport layers (ETLs) with pronounced electron conducting capability are essential for high performance planar perovskite photovoltaics, with the great challenge being that the most widely used metal oxide ETLs unfortunately have intrinsically low carrier mobility. Herein is demonstrated that by simply addressing the carrier loss at particle boundaries of TiO2 ETLs, through embedding in ETL p-n heterointerfaces, the electron mobility of the ETLs can be boosted by three orders of magnitude. Such embedding is encouragingly favorable for both inhibiting the formation of rutile phase TiO2 in ETL, and initiating the growth of high-quality perovskite films with less defect states. By virtue of these merits, creation of formamidinium lead iodide perovskite solar cells (PSCs) with a champion efficiency of 25.05% is achieved, setting a new benchmark for planar PSCs employing TiO2 ETLs. Unencapsulated PSCs deliver much-improved environmental stability, i.e., more than 80% of their initial efficiency after 9000 h of air storage under RH of 40%, and over 90% of their initial efficiency at maximum power point under continuous illumination for 500 h. Further work exploring other p-type nanocrystals for embedding warrants the proposed strategy as a universal alternative for addressing the low-carrier mobility of metal oxide based ETLs.

Variability of CPR training requirements among New Zealand health professionals.

AIM: To audit cardiopulmonary resuscitation (CPR) training and certification requirements of registered healthcare professionals in New Zealand. METHOD: An enquiry-based policy audit of all regulatory bodies under the Health Practitioners Competence Assurance Act 2003 (HPCA Act 2003), and vocational medical training and recertification providers accredited by the Medical Council of New Zealand (MCNZ). RESULTS: All the organisations approached (n=37) responded to the audit. Six of the 17 health professional regulatory bodies have some form of mandatory CPR certification requirement for initial registration, ongoing registration, or continuing professional development. The Midwifery Council, Dentistry Council, Podiatrists Board, and Pharmacy Council have the most comprehensive requirements. Twelve of the 20 vocational medical colleges specify some form of CPR training. The Royal New Zealand College of Urgent Care is the only one to require annual re-certification. CONCLUSION: This audit revealed a wide variety of CPR training and certification requirements across health professions in New Zealand. Future studies should investigate whether mandating CPR training improves outcomes from cardiac arrest and consider patient, public, and whanau expectations regarding the ongoing certification of healthcare professionals in resuscitation and emergency care.

Image discrimination reversal learning is impaired by sleep deprivation in rats: Cognitive rigidity or fatigue?

Introduction: Insufficient sleep is pervasive worldwide, and its toll on health and safety is recapitulated in many settings. It is thus important to understand how poor sleep affects the brain and decision making. A robust literature documents the adverse effects of sleep deprivation on cognitive processes including cognitive flexibility, which is the capacity to appraise new feedback and make behavioral adjustments to respond appropriately. Animal models are often used to unravel the molecules, genes and neural circuits that are altered by sleep loss. Herein we take a translational approach to model the effects of sleep deprivation on cognitive rigidity, i.e., impaired cognitive flexibility in rats. Methods: There are several approaches to assess cognitive rigidity; in the present study, we employ a pairwise discrimination reversal task. To our knowledge this is the first time this paradigm has been used to investigate sleep deprivation. In this touchscreen operant platform, we trained rats to select one of two images to claim a sucrose pellet reward. If the non-rewarded image was selected the rats proceeded to a correction trial where both images were presented in the same position as before. This image presentation continued until the rat selected the correct image. Once rats reached performance criteria, the reward contingencies were reversed. In one group of rats the initial reversal session was preceded by 10 h of sleep deprivation. We compared those rats to controls with undisturbed sleep on the number of sessions to reach performance criteria, number of trials per session, response latencies, correct responses, errors, perseverative errors and perseveration bouts in the initial training and reversal phases. Results: We report that on reversal session one, sleep deprived rats completed a fraction of the trials completed by controls. On subsequent reversal sessions, the sleep deprived rats struggled to adapt to the reversed contingencies despite completing a similar number of trials, suggesting an effect of cognitive rigidity separate from fatigue. Discussion: We discuss the delayed performance dynamics incurred by sleep loss in the context of fatigue and the implications of using pairwise discrimination reversal as a model to further examine the effects of sleep loss on adaptive decision making.

The rat Lux Actuating Search Task (LAST) and effects of sleep deprivation on task reversal performance.

Sleep deprivation (SD) causes significant deficits in multiple aspects of cognition, including sustained attention and working memory. Investigating the neural processes underpinning these cognitive losses has proven challenging due to the confounds of current animal tasks; many employ appetitive or aversive stimuli to motivate behavior, while others lack task complexity that translates to human studies of executive function. We established the Lux Actuating Search Task (LAST) to circumvent these issues. The LAST is performed in a circular, open-field arena that requires rats to find an unmarked, quasi-randomly positioned target. Constant low-level floor vibrations motivate ambulation, while light intensity (determined by the rodent's proximity to the target destination) provides continuous visual feedback. The task has two paradigms that differ based on the relationship between the light intensity and target proximity: the Low Lux Target (LLT) paradigm and the High Lux Target paradigm (HLT). In this study, on days 1-6, the rats completed nine trials per day on one of the two paradigms. On day 7, the rats were either sleep deprived by gentle handling or were left undisturbed before undertaking the opposite (reversal) paradigm on days 7-9. Our results showed that SD significantly impeded the ability of Long Evans rats to learn the reversal paradigm, as indicated by increased times to target and increased failure percentages compared to rats whose sleep was undisturbed. Rats also showed reduced learning with the HLT paradigm, as the initial task or as the reversal task, likely due to the rodents' photophobia limiting their motivation to navigate toward a bright light, which is required to succeed.

Urinary Trace Elements Are Biomarkers for Early Detection of Acute Kidney Injury.

Introduction: Acute kidney injury (AKI) is common in hospitalized patients and associated with poor outcomes. Current methods for identifying AKI (rise in serum creatinine [sCr] or fall in urine output [UO]) are inadequate and delay detection. Early detection of AKI with easily measurable biomarkers might improve outcomes by facilitating early implementation of AKI care pathways. Methods: From a porcine model of AKI, we identified trace elements (TEs) in urine that were associated with subsequent development of AKI. We tested these putative biomarkers in 2 observational cohort studies of patients at high risk of AKI: 151 patients undergoing cardiac surgery and 150 patients admitted to a general adult intensive care unit (ICU). Results: In adults admitted to the ICU, urinary cadmium (Cd) (adjusted for urinary creatinine) had area under the receiver operating characteristic curve (AUROC) 0.70 and negative predictive value (NPV) 89%; copper (Cu) had AUROC 0.76 and NPV 91%. In humans (but not pigs), urinary zinc (Zn) was also associated with AKI and, in the ICU study, had AUROC 0.67 and NPV 80%. In patients undergoing cardiac surgery, Zn had AUROC 0.77 and NPV 91%; urinary Cd and Cu had poor AUROC but NPV of 93% and 95%, respectively. In control studies, we found that the urinary biomarkers are stable at room temperature for at least 14 days and are not affected by other confounding factors, such as chronic kidney disease (CKD). Conclusion: Urinary Cd, Cu, and Zn are novel biomarkers for early detection of AKI. Urinary trace metals have advantages over proteins as AKI biomarkers because they are stable at room temperature and have potential for cheap point-of-care testing using electrochemistry.

Intra-tracheal multiplexed sensing of contact pressure and perfusion.

Incorrect endotracheal tube (ETT) cuff inflation pressure causes significant problems for intubated patients. The technical development and first in vivo use of a smart ETT for measurements at the cuff-trachea interface during mechanical ventilation are described. The intra-tracheal multiplexed sensing (iTraXS) ETT contains integrated optical fibre sensors to measure contact pressure and blood perfusion. The device is tested during mechanical ventilation in a porcine model (N=6). For contact pressure, signals were obtained in all 30 measurements. For perfusion, data could be obtained in all 33 measurements. In the 3 cases where the cuff was inflated to an artificially high-level, blood occlusion is observed.

Activating a Semiconductor-Liquid Junction via Laser-Derived Dual Interfacial Layers for Boosted Photoelectrochemical Water Splitting.

The semiconductor-liquid junction (SCLJ), the dominant place in photoelectrochemical (PEC) catalysis, determines the interfacial activity and stability of photoelectrodes, whcih directly affects the viability of PEC hydrogen generation. Though efforts dedicated in past decades, a challenge remains regarding creating a synchronously active and stable SCLJ, owing to the technical hurdles of simultaneously overlaying the two advantages. The present work demonstrates that creating an SCLJ with a unique configuration of the dual interfacial layers can yield BiVO4 photoanodes with synchronously boosted photoelectrochemical activity and operational stability, with values located at the top in the records of such photoelectrodes. The bespoke dual interfacial layers, accessed via grafting laser-generated carbon dots with phenolic hydroxyl groups (LGCDs-PHGs), are experimentally verified effective, not only in generating the uniform layer of LGCDs with covalent anchoring for inhibited photocorrosion, but also in activating, respectively, the charge separation and transfer in each layer for boosted charge-carrier kinetics, resulting in FeNiOOH-LGCDs-PHGs-MBVO photoanodes with a dual configuration with the photocurrent density of 6.08 mA cm-2 @ 1.23 VRHE , and operational stability up to 120 h @ 1.23 VRHE . Further work exploring LGCDs-PHGs from catecholic molecules warrants the proposed strategy as being a universal alternative for addressing the interfacial charge-carrier kinetics and operational stability of semiconductor photoelectrodes.

Knowledge and perceptions of cardiopulmonary resuscitation amongst New Zealand podiatrists: a web-based survey.

BACKGROUND: Podiatrists in New Zealand have a duty of care to assist patients in an emergency, and current cardiopulmonary resuscitation (CPR) certification is a requirement for registration. However, it is unknown how competent and confident podiatrists are in administering CPR and how they would respond in an emergency. Having a health professional who has a competent knowledge of CPR and skills in basic life support, can improve survival rates from sudden cardiac arrest. Therefore, the aim of this study was to survey New Zealand podiatrists to determine their CPR knowledge and qualifications; beliefs about the application of CPR; and perceptions of their competency in CPR. METHODS: This cross-sectional study used a web-based survey. Participants were New Zealand registered podiatrists with a current annual practising certificate. The 31-item survey included questions to elicit demographic information, CPR practice and attitudes, and CPR knowledge. Responses were collected between March and August 2020. RESULTS: 171 podiatrists responded to the survey. 16 % of the podiatrists (n = 28) had performed CPR in an emergency, with a 50 % success rate. Participants were predominantly female (n = 127, 74 %) and working in private practice (n = 140,82 %). Nearly half of respondents were younger than 40 years (n = 75,44 %) and had less than 10 years of clinical experience (n = 73, 43 %). Nearly all (n = 169,97 %) participants had received formal CPR training in the past two years, with 60 % (n = 105) receiving training in the past 12 months. Most respondents (n = 167,98 %) self-estimated their CPR ability as being effective, very effective, or extremely effective. Participants' knowledge of CPR was variable, with the percentage of correct answers for CPR protocol statements ranging between 20 and 90 %. CONCLUSIONS: This study provides the first insight into New Zealand podiatrists' CPR knowledge and perceptions. Podiatrists were found to have high levels of CPR confidence but demonstrated gaps in CPR knowledge. Currently, New Zealand registered podiatrists require biennial CPR re-certification. However, resuscitation authorities in New Zealand and overseas recommend an annual update of CPR skills. Based on this study's findings, and in line with Australia and the United Kingdom, the authors recommend a change from biennial to annual CPR re-certification for podiatrists in New Zealand. TRIAL REGISTRATION: The study was registered with the Australian New Zealand Clinical Trials Registry ( ACTRN12620001144909 ).

Floor vibrations for motivation and feedback in the rat vibration actuating search task.

Motivating rodents to perform cognitive tasks often relies on the application of aversive stimuli. The Vibration Actuating Search Task (VAST) is a novel open-field task in which gradient floor vibration provides motivation for the rodent to navigate in the direction of diminishing vibration to an unmarked target destination. Using floor vibration as a motivational stimulus may overcome several of the potential confounds associated with stimuli used in other tasks. In a series of three experiments, we determined whether (1) rats exhibit place preference for floor vibration over other aversive stimuli (i.e., water, foot shock, and bright light), (2) exposure to floor vibration is associated with a lower corticosterone response than exposure to these other stimuli, (3) rats successfully acquire the VAST, and (4) VAST performance is sensitive to 6 h of sleep deprivation (SD). Our results showed that rats exhibited place preference for vibration over water, foot shock, and bright light environments, and that corticosterone levels were lower in rats exposed to vibration than those exposed to water. VAST performance also significantly improved over two days of testing for some metrics, and SD impaired VAST performance. Overall, we conclude that (1) rats exhibit place preference for vibration over other stimuli commonly used to motivate task performance, (2) the vibrations employed by the VAST produce lower concentrations of circulating corticosterone than forced swimming, (3) rats can learn to use gradient floor vibration as a mode of performance feedback within two days of testing, and (4) VAST performance is substantially impaired by SD. Thus, the VAST is an effective and practical testbed for studying the mechanisms by which SD causes deficits in feedback-dependent decision making.

Interfacial Embedding of Laser-Manufactured Fluorinated Gold Clusters Enabling Stable Perovskite Solar Cells with Efficiency Over 24.

Tackling the interfacial loss in emerged perovskite-based solar cells (PSCs) to address synchronously the carrier dynamics and the environmental stability, has been of fundamental and viable importance, while technological hurdles remain in not only creating such interfacial mediator, but the subsequent interfacial embedding in the active layer. This article reports a strategy of interfacial embedding of hydrophobic fluorinated-gold-clusters (FGCs) for highly efficient and stable PSCs. The p-type semiconducting feature enables the FGC efficient interfacial mediator to improve the carrier dynamics by reducing the interfacial carrier transfer barrier and boosting the charge extraction at grain boundaries. The hydrophobic tails of the gold clusters and the hydrogen bonding between fluorine groups and perovskite favor the enhancement of environmental stability. Benefiting from these merits, highly efficient formamidinium lead iodide PSCs (champion efficiency up to 24.02%) with enhanced phase stability under varied relative humidity (RH) from 40% to 95%, as well as highly efficient mixed-cation PSCs with moisture stability (RH of 75%) over 10 000 h are achieved. It is thus inspiring to advance the development of highly efficient and stable PSCs via interfacial embedding laser-generated additives for improved charge transfer/extraction and environmental stability.

Structural definition of polyspecific compensatory ligand recognition by P-glycoprotein.

The multidrug transporter P-glycoprotein (Pgp)/ABCB1/MDR1 plays an important role in multidrug resistance (MDR) and detoxification owing to its ability to efflux an unusually large and chemically diverse set of substrates. Previous phenylalanine-to-alanine scanning mutagenesis of Pgp revealed that nearly all mutations retained full MDR function and still permitted substrate transport. This suggests that either the loss of any single aromatic side chain did not affect the ligand-binding modes or that highly adaptive and compensatory drug recognition is an intrinsic property including ligand-binding shifts that preserve function. To explore this hypothesis, the ATPase function and crystallographic localization of five single-site mutations in which the native aromatic residue directly interacted with the environmental pollutant BDE-100, as shown in previous crystal structures, were tested. Two mutants, Y303A and Y306A, showed strong BDE-100 occupancy at the original site (site 1), but also revealed a novel site 2 located on the opposing pseudo-symmetric half of the drug-binding pocket (DBP). Surprisingly, the F724A mutant structure had no detectable binding in site 1 but exhibited a novel site shifted 11 Šfrom site 1. ATPase studies revealed shifts in ATPase kinetics for the five mutants, but otherwise indicated a catalytically active transporter that was inhibited by BDE-100, similar to wild-type Pgp. These results emphasize a high degree of compensatory drug recognition in Pgp that is made possible by aromatic amino-acid side chains concentrated in the DBP. Compensatory recognition forms the underpinning of polyspecific drug transport, but also highlights the challenges associated with the design of therapeutics that evade efflux altogether.

A Role for Astroglial Calcium in Mammalian Sleep and Sleep Regulation.

Mammalian sleep expression and regulation have historically been thought to reflect the activity of neurons. Changes in other brain cells (glia) across the sleep-wake cycle and their role in sleep regulation are comparatively unexplored. We show that sleep and wakefulness are accompanied by state-dependent changes in astroglial activity. Using a miniature microscope in freely behaving mice and a two-photon microscope in head-fixed, unanesthetized mice, we show that astroglial calcium signals are highest in wake and lowest in sleep and are most pronounced in astroglial processes. We also find that astroglial calcium signals during non-rapid eye movement sleep change in proportion to sleep need. In contrast to neurons, astrocytes become less synchronized during non-rapid eye movement sleep after sleep deprivation at the network and single-cell level. Finally, we show that conditionally reducing intracellular calcium in astrocytes impairs the homeostatic response to sleep deprivation. Thus, astroglial calcium activity changes dynamically across vigilance states, is proportional to sleep need, and is a component of the sleep homeostat.

Real time monitoring of biofilm formation on coated medical devices for the reduction and interception of bacterial infections.

Real time monitoring of bacterial attachment to medical devices provides opportunities to detect early biofilm formation and instigate appropriate interventions before infection develops. This study utilises long period grating (LPG) optical fibre sensors, incorporated into the lumen of endotracheal tubes (ETTs), to monitor in real time, Pseudomonas aeruginosa surface colonisation and biofilm formation. The wavelength shift of LPG attenuation bands was monitored for 24 h and compared with biofilm biomass, quantified using confocal fluorescence microscopy imaging. Biofilm formation was compared on uncoated ETTs and optical fibres, and on a biofilm resistant acrylate polymer, after challenge in an artificial sputum or minimal growth medium (RPMI-1640). The LPG sensor was able to detect a biofilm biomass as low as 81 µg cm-2, by comparison with the confocal image quantification. An empirical exponential function was found to link the optical attenuation wavelength shift with the inverse of the biofilm biomass, allowing quantification of biofouling from the spectral response. Quantification from the sensor allows infection interception and early device removal, to reduce, for example, the risk of ventilator associated pneumonia.