Daylight driven vertical migration of mesozooplankton in the Arabian sea and the Bay of Bengal.

Diurnal vertical migration (DVM) of mesozooplankton in the Deep Scattering Layer (DSL) of the Indian seas is poorly studied. This cyclical vertical migration substantially controls the carbon sequestration in the ocean. The present research is a comprehensive examination to analyse the factors affecting the DVM pattern of the zooplankton community in the Arabian Sea (AS) and the Bay of Bengal (BoB). Echo sounder profiling was conducted at shallow depths (∼10-400m) of the AS (January 2023) and BoB (March 2023) with a period of 24 h to monitor the DVM pattern of the DSL. Vertical migration in both basins showcased the notable influence of the spatio-temporal contrast in the occurrence of daybreak, with the day (descend) and night (ascend) cycle of the DSL. Delayed descent was observed in the AS contrary to BoB, owing to the delayed day break in the AS relative to BoB. Intensity and temporal pattern of the incoming solar radiation were correlated with the DVM whereas diurnal variation of sea surface temperature was observed to be contrasting. The preliminary analysis is indicative of the diversified community structure of the zooplankton community in these basins resulting from the vertical migration. Furthermore, it is conclusive that the surface residence time of the zooplankton is distinct and is affirmed based on daybreak and light intensity particular for each basin. Since daybreak vary with the geolocation, sole dependence on a particular time for migration study can be erroneous, which is highlighted in the present study.

Year-to-year variability of oil pollution along the Eastern Arabian Sea: The impact of COVID-19 imposed lock-downs.

This study investigated the year-to-year variability in the occurrence, abundance and sources of oil spills in the Eastern Arabian Sea (EAS) using sentinel-1 imagery and identified the potential oil spills vulnerable zones. The four consecutive year's data acquired from 2017 to 2020 (March-May) reveal three oil spill hot spot zones. The ship-based oil spills were dominant over zone's-1 (off Gujarat) and 3 (off Karnataka and Kerala), and the oil field based over zone-2 (off Maharashtra). The abundance of oil spills was significantly low in zone-1, only 14.30km2 (1.2%) during lock-down due to the covid-19 pandemic. Whereas, the year-to-year oil spills over zone's 2 and 3 are not significantly varied (170.29 km2 and 195.01 km2), further suggesting the influence of oil exploration and international tanker traffic are in operation during the lock-down. This study further recommends that manual clustering is the best method to study the distribution of unknown oil spills.

Fate of MV Wakashio oil spill off Mauritius coast through modelling and remote sensing observations.

This study aims at assessing the fate of MV Wakashio oil spill, and the driving forces responsible for possible environmental consequences of polluted coastal region. GNOME simulations were performed, considering various meteo-oceanographic forcings such as (i) winds and currents, (ii) only winds, and (iii) only winds with different diffusion coefficients, and validated with the satellite images. The results revealed that the simulations performed with 'only winds' reasonably match with the satellite observations, indicating that winds are the primary driving forces. The conducive stokes drift is an added contribution to the predominant northwestward drift of the spill. The oil budget analysis suggests that beaching and evaporation together accounted for a significant portion of the spilled oil (1000 tons), in which ~60% of the oil was accounted only for beaching. Our results depict that the diffusion coefficient of 100,000 cm2/s and 3% windages are optimal for oil-spill simulations off the southeastern Mauritius coast.

Estimate the Unknown Environment with Biosonar Echoes-A Simulation Study.

Unmanned aerial vehicles (UAVs) have shown great potential in various applications such as surveillance, search and rescue. To perform safe and efficient navigation, it is vitally important for a UAV to evaluate the environment accurately and promptly. In this work, we present a simulation study for the estimation of foliage distribution as a UAV equipped with biosonar navigates through a forest. Based on a simulated forest environment, foliage echoes are generated by using a bat-inspired bisonar simulator. These biosonar echoes are then used to estimate the spatial distribution of both sparsely and densely distributed tree leaves. While a simple batch processing method is able to estimate sparsely distributed leaf locations well, a wavelet scattering technique coupled with a support vector machine (SVM) classifier is shown to be effective to estimate densely distributed leaves. Our approach is validated by using multiple setups of leaf distributions in the simulated forest environment. Ninety-seven percent accuracy is obtained while estimating thickly distributed foliage.

Transarticular Fixation Following Mobilization of "High-Riding" Vertebral Artery.

BACKGROUND AND IMPORTANCE: The article identifies the feasibility of transarticular screw fixation after mobilizing the vertebral artery in cases where it is in a "high-riding" location. CLINICAL PRESENTATION: A 42-yr-old male patient had a 4-yr history of progressive quadriparesis. Investigations revealed severe basilar invagination. There was assimilation of atlas and C2-3 fusion. The vertebral artery was "high-riding" into the pedicle-facet of C2 vertebra on both sides. Vertebral artery loop was exposed and mobilized inferiorly on both sides after careful drilling of pedicular bone on the posterior aspect of the dome of the artery. C2 facetal bone on the anterior face of the vertebral artery dome was now available for screw insertion. The C1-2 facets and the articulation were directly in line, making transarticular screw fixation relatively straightforward. The wide bone space available permitted insertion of 2 screws in a transarticular fashion on both sides. The patient had satisfactory clinical improvement. Imaging after 22 mo showed bone fusion across the facets. CONCLUSION: Mobilization of the high-riding vertebral artery loop can help salvage the surgical procedure of lateral mass stabilization.

Patient Safety Incidents Describing Patient Falls in Critical Care in North West England Between 2009 and 2017.

AIM: The aim of the study was to review reported falls in critical care units to see whether the causes and results were different from those described in a general hospital population. METHODS: We reviewed and classified patient safety incidents describing falls from critical care units in the North West of England between 2009 and 2017. The classification reviewed patient and staff factors contributing to the fall, the environment of the fall, and the reported consequences. We then calculated and compared rates of falls in different units. RESULTS: There were 914 falls reported, representing only 2.0% of all reported incidents. The median (interquartile range) unit rate was 1.0 falls per 1000 (0.5-1.2) days, and falls were unrelated to the number of single rooms and were no more common in specialist units. There were 304 (33%) falls in patients transferring (207 to standing, 8 from standing), and there were 259 (28%) falls from bed. Patient factors included attempting tasks without assistance (323 incidents [35%]) and organic confusion (188 incidents [21%]). Staff factors included being away from the patient (375 incidents [41%]). Harm was described in 201 incidents (22%), including removal of medical devices (40 incidents), injury to staff (10 incidents) subdural hematoma, and possible spinal injury (1 incident each). CONCLUSIONS: There is a low rate of falls and associated harm in critical care units. The variation between units suggests that this rate could be further reduced by the prevention and management of delirium and by educating patients and staff to take care when moving patients to the standing position.

A simulation framework for bio-inspired sonar sensing with Unmanned Aerial Vehicles.

We introduce a unified simulation framework that generates natural sensing environments and produces biosonar echoes under various sensing scenarios. This framework produces rich sensory data with environmental information completely known, thus can be used for the training of robotic algorithms for biosonar-based Unmanned Aerial Vehicles. The simulated environment consists of random trees with full geometry of the tree foliage. To simulate a single tree, we adopt the Lindenmayer system to generate the initial branching pattern and integrate that with the available measurements of the 3D computer-aided design object files to create natural-looking branches, sub-branches, and leaves. A forest is formed by simulating trees at random locations generated by using an inhomogeneous Poisson process. While our simulated environments can be generally used for testing other sensors and training robotic algorithms, in this study we focus on testing bat-inspired Unmanned Aerial Vehicles that recreate bat's flying behavior through biosonar sensors. To this end, we also introduce an foliage echo simulator that produces biosonar echoes while mimicking bat's biosonar system. We demonstrate the application of the proposed simulation framework by generating real-world scenarios with multiple trees and computing the resulting impulse responses under static or dynamic motions of an Unmanned Aerial Vehicle.

Unplanned Removal of Medical Devices in Critical Care Units in North West England Between 2011 and 2016.

BACKGROUND: The unplanned removal of medical devices poses a risk of harm to critically ill patients. OBJECTIVE: To determine rates, causes, and consequences of unplanned medical device removal, as well as factors mitigating harm to patients, in critical care units in the United Kingdom by reviewing patient safety incident reports. METHODS: Incidents of unplanned medical device removal in critical care units in North West England between 2011 and 2016 were retrospectively reviewed and classified. The incidents were classified by type of device displaced, staff and patient factors, causes and consequences of removal, and staff actions following removal. Displacement rates were calculated per 1000 patient days per unit. RESULTS: A total of 34 705 incident reports were reviewed, of which 1090 described unplanned device removal. The median rate of device removal was 0.7 (interquartile range, 0.4-2.2) per 1000 patient days per unit. Devices displaced most commonly included nasogastric tubes (317), central catheters (245), tracheostomy tubes (174), and endotracheal tubes (140). A total of 11 cardiac arrests were reported (8 associated with airway devices and 3 with central catheters). Factors contributing to displacement included initial placement (188), patient factors (563), and manual handling (238). Manual handling was cited in 49% of central catheter incidents and only 9% of nasogastric tube incidents. Patients' organic confusion was a factor in 16% of endotracheal tube and 80% of nasogastric tube removals. CONCLUSIONS: Unplanned device removal may cause patient harm and is often preventable. The causes and consequences depend on the type of device removed.

Establishing the use of a safety attitudes questionnaire to assess the safety climate across a critical care network.

AIMS: We aimed to measure the safety culture across a network of critical care units to compare units, track temporal changes and to present easy to interpret information back to staff. METHODS: We provided adapted paper versions of the short ICU 'Safety attitude questionnaire' to 14 critical care units annually between 2015 and 2017. The responses were analysed to establish scores for individual safety domains. Feedback used colour conditional formatted tables to allow easy identification of high and low scores. RESULTS: There was an inverse relation between median unit score and standardised mortality (rs = 0.4). Rates of staff fatigue increased between 2016 and 2017 (two-point change on a 1-5 scale). CONCLUSIONS: A critical care network can usefully collect and feedback safety attitude questionnaires which show a relationship with patient outcome. Units should monitor overtime working.

Characterization of vascular permeability using a biomimetic microfluidic blood vessel model.

The inflammatory response in endothelial cells (ECs) leads to an increase in vascular permeability through the formation of gaps. However, the dynamic nature of vascular permeability and external factors involved is still elusive. In this work, we use a biomimetic blood vessel (BBV) microfluidic model to measure in real-time the change in permeability of the EC layer under culture in physiologically relevant flow conditions. This platform studies the dynamics and characterizes vascular permeability when the EC layer is triggered with an inflammatory agent using tracer molecules of three different sizes, and the results are compared to a transwell insert study. We also apply an analytical model to compare the permeability data from the different tracer molecules to understand the physiological and bio-transport significance of endothelial permeability based on the molecule of interest. A computational model of the BBV model is also built to understand the factors influencing transport of molecules of different sizes under flow. The endothelial monolayer cultured under flow in the BBV model was treated with thrombin, a serine protease that induces a rapid and reversible increase in endothelium permeability. On analysis of permeability data, it is found that the transport characteristics for fluorescein isothiocyanate (FITC) dye and FITC Dextran 4k Da molecules are similar in both BBV and transwell models, but FITC Dextran 70k Da molecules show increased permeability in the BBV model as convection flow (Peclet number > 1) influences the molecule transport in the BBV model. We also calculated from permeability data the relative increase in intercellular gap area during thrombin treatment for ECs in the BBV and transwell insert models to be between 12% and 15%. This relative increase was found to be within range of what we quantified from F-actin stained EC layer images. The work highlights the importance of incorporating flow in in vitro vascular models, especially in studies involving transport of large size objects such as antibodies, proteins, nano/micro particles, and cells.

Biomimetic channel modeling local vascular dynamics of pro-inflammatory endothelial changes.

Endothelial cells form the inner lining of blood vessels and are exposed to various factors like hemodynamic conditions (shear stress, laminar, and turbulent flow), biochemical signals (cytokines), and communication with other cell types (smooth muscle cells, monocytes, platelets, etc.). Blood vessel functions are regulated by interactions among these factors. The occurrence of a pathological condition would lead to localized upregulation of cell adhesion molecules on the endothelial lining of the blood vessel. This process is promoted by circulating cytokines such as tumor necrosis factor-alpha, which leads to expression of intercellular adhesion molecule-1 (ICAM-1) on the endothelial cell surface among other molecules. ICAM-1 is critical in regulating endothelial cell layer dynamic integrity and cytoskeletal remodeling and also mediates direct cell-cell interactions as part of inflammatory responses and wound healing. In this study, we developed a biomimetic blood vessel model by culturing confluent, flow aligned, endothelial cells in a microfluidic platform, and performed real time in situ characterization of flow mediated localized pro-inflammatory endothelial activation. The model mimics the physiological phenomenon of cytokine activation of endothelium from the tissue side and studies the heterogeneity in localized surface ICAM-1 expression and F-actin arrangement. Fluorescent antibody coated particles were used as imaging probes for identifying endothelial cell surface ICAM-1 expression. The binding properties of particles were evaluated under flow for two different particle sizes and antibody coating densities. This allowed the investigation of spatial resolution and accessibility of ICAM-1 molecules expressed on the endothelial cells, along with their sensitivity in receptor-ligand recognition and binding. This work has developed an in vitro blood vessel model that can integrate various heterogeneous factors to effectively mimic a complex endothelial microenvironment and can be potentially applied for relevant blood vessel mechanobiology studies.

Highly efficient and selective isolation of rare tumor cells using a microfluidic chip with wavy-herringbone micro-patterned surfaces.

Circulating tumor cells (CTCs) in peripheral blood have been recognized as a general biomarker for diagnosing cancer and providing guidance for personalized treatments. Yet due to their rarity, the challenge for their clinical utility lies in the efficient isolation while avoiding the capture of other non-targeted white blood cells (WBCs). In this paper, a wavy-herringbone (HB) microfluidic chip coated with antibody directly against epithelial cell adhesion molecule (anti-EpCAM) was developed for highly efficient and selective isolation of tumor cells from tumor cell-spiked whole blood samples. By extending the concept of the hallmark HB-Chip in the literature, the wavy-HB chip not only achieves high capture efficiency (up to 85.0%) by micro-vortexes induced by HB structures, but also achieves high purity (up to 39.4%) due to the smooth wavy microstructures. These smooth wavy-HB structures eliminate the ultra-low shear rate regions in the traditional grooved-HB structures that lead to non-specific trapping of cells. Compared with the grooved-HB chip with sharp corners, the wavy-HB chip shows significantly higher purity while maintaining similarly high capture efficiency. Furthermore, the wavy-HB chip has up to 11% higher captured cell viability over the grooved-HB chip. The distributions of tumor cells and WBCs along the grooves and waves are investigated to help understand the mechanisms behind the better performance of the wavy-HB chip. The wavy-HB chip may serve as a promising platform for CTC capture and cancer diagnosis.

Correlation of cervical cytology with high-risk HPV molecular diagnosis, genotypes, and histopathology--A four year study from the UAE.

BACKGROUND: Cervical cancer is one of the most common cancers among women in the world and in the Middle East. Its prevention and screening strategies assume great importance especially in view of the ability to identify the illness at an early stage and disrupt its progression toward neoplasia. Cervical cancer screening program of our center in UAE as well as this study is oriented in this direction. METHODS: Cervical cytology data encompassing 4 years (2011-2014) was compiled and analyzed for 14,950 cases to assess the abnormal smear reporting pattern, correlation with biopsy histopathology, HPV high-risk screening data, and HPV genotype prevalence among patients with abnormal smear test, as well as in relation to the respective nationalities of patients. RESULTS: Abnormal smear rates as well as HPV high-risk positivity correlated well with established data. Cytology-histology correlation was good. HPV high-risk type 16 was the commonest, type 18 which is the second common type worldwide was less frequently detected, several other high risk subtypes such as 51, 31 as well as rare types such as 66, 56, and 59 were detected in a significant number of patients. CONCLUSION: Assessment of cervical cytology reporting pattern, correlation of cervical cytology with HPV molecular diagnosis, and biopsy histopathology is a useful way to audit our work and a good quality control practice. Higher prevalence of HPV HR types such as type 51, 31 as well as 66, 56, and 59 found in the present as well as many similar other studies apart from the commonest subtype 16 may imply necessity for development of more targeted and multivalent anti-HPV vaccines for protection of women in our region. HPV genotypes correlation with the nationalities of patients is useful from an epidemiological standpoint to plan preventive strategies.

Patient safety incidents associated with failures in communication reported from critical care units in the North West of England between 2009 and 2014.

Communication is central to the safe and effective delivery of critical care. We present a retrospective analysis of hospital incident reports attributed to communication that were generated by 30 intensive care units in the North West of England from 2009 to 2014. We reviewed when during the critical care pathway incidents occur, the personnel involved, the method of communication used, the type of information communicated and the level of harm associated with the incident. We found that patient safety incidents tend to occur when patients are transferred into or out of the intensive care unit and when information has to be communicated to other teams during the critical care stay. We then examine ways that the patient handover process may be modified to improve communication and safety.

An analysis of patient safety incident reports describing injuries to staff working in critical care in the North West of England between 2009 and 2013.

BACKGROUND: Critical care environments are potentially high-risk areas for staff harm due to procedural demand and increased incidence of delirium/dependence. The principal types of harm and temporal trends have not yet been quantified. METHODS: Retrospective analysis of a multicentre dataset prospectively collected over a five-year period. All patient safety incidents reported to a regional network project were analysed; those recorded as staff harm were extracted, quantified and assessed by thematic analysis to identify key areas of harm, temporal trends and incident rates. RESULTS: Staff harm accounted for 7% of all reported patient safety incidents over the study period. Incident rates remained static, ranging annually from 2.6 to 3.7 episodes/1000 patient days. Assaults on staff accounted for the highest proportional contribution on thematic analysis, which was a consistent annual finding. Sharps injuries and manual handling incidents were also notable contributions. Temporal trends for each theme remained static over the study period implying limited reduction in staff harm despite implementation of national guidance and local initiatives. CONCLUSION: Staff harm is a consistent issue for those working in critical care. Assaults on staff appear to be the highest contributor on thematic analysis. These data imply significant reduction in harm can still be achieved and can be used to design and implement interventional measures.

Characterization of nanoparticle delivery in microcirculation using a microfluidic device.

This work focuses on the characterization of particle delivery in microcirculation through a microfluidic device. In microvasculature the vessel size is comparable to that of red blood cells (RBCs) and the existence of blood cells largely influences the dispersion and binding distribution of drug loaded particles. The geometry of the microvasculature leads to non-uniform particle distribution and affects the particle binding characteristics. We perform an in vitro study in a microfluidic chip with micro vessel mimicking channels having a rectangular cross section. Various factors that influence particle distribution and delivery such as the vessel geometry, shear rate, blood cells, particle size, particle antibody density are considered in this study. Around 10% higher particle binding density is observed at bifurcation regions of the mimetic microvasculature geometry compared to straight regions. Particle binding density is found to decrease with increased shear rates. RBCs enhance particle binding for both 210 nm and 2 µm particles for shear rates between 200-1600 s(-1) studied. The particle binding density increases about 2-3 times and 6-10 times when flowing in whole blood at 25% RBC concentration compared to the pure particle case, for 210 nm and 2 µm particles respectively. With RBCs, the binding enhancement is more significant for 2 µm particles than that for 210 nm particles, which indicates an enhanced size dependent exclusion of 2 µm particles from the channel centre to the cell free layer (CFL). Increased particle antibody coating density leads to higher particle binding density for both 210 nm and 2 µm particles.

The influence of size, shape and vessel geometry on nanoparticle distribution.

Nanoparticles (NPs) are emerging as promising carrier platforms for targeted drug delivery and imaging probes. To evaluate the delivery efficiency, it is important to predict the distribution of NPs within blood vessels. NP size, shape and vessel geometry are believed to influence its biodistribution in circulation. Whereas, the effect of size on nanoparticle distribution has been extensively studied, little is known about the shape and vessel geometry effect. This paper describes a computational model for NP transport and distribution in a mimetic branched blood vessel using combined NP Brownian dynamics and continuum fluid mechanics approaches. The simulation results indicate that NPs with smaller size and rod shape have higher binding capabilities as a result of smaller drag force and larger contact area. The binding dynamics of rod-shaped NPs is found to be dependent on their initial contact points and orientations to the wall. Higher concentration of NPs is observed in the bifurcation area compared to the straight section of the branched vessel. Moreover, it is found that Péclet number plays an important role in determining the fraction of NPs deposited in the branched region and the straight section. Simulation results also indicate that NP binding decreases with increased shear rate. Dynamic NP re-distribution from low to high shear rates is observed due to the non-uniform shear stress distribution over the branched channel. This study would provide valuable information for NP distribution in a complex vascular network.

The shape of things to come: importance of design in nanotechnology for drug delivery.

The design of nanoparticle (NP) size, shape and surface chemistry has a significant impact on their performance. While the influences of the particle size and surface chemistry on drug delivery have been studied extensively, little is known about the effect of particle shapes on nanomedicine. In this perspective article, we discuss recent progress on the design and fabrication of NPs of various shapes and their unique delivery properties. The shapes of these drug carriers play an important role in therapeutic delivery processes, such as particle adhesion, distribution and cell internalization. We envision that stimuli-responsive NPs, which actively change their shapes and other properties, might pave way to the next generation of nanomedicine.

Influence of Red Blood Cells on Nanoparticle Targeted Delivery in Microcirculation.

Multifunctional nanomedicine holds considerable promise as the next generation of medicine that allows for targeted therapy with minimal toxicity. Most current studies on Nanoparticle (NP) drug delivery consider a Newtonian fluid with suspending NPs. However, blood is a complex biological fluid composed of deformable cells, proteins, platelets, and plasma. For blood flow in capillaries, arterioles and venules, the particulate nature of the blood needs to be considered in the delivery process. The existence of the cell-free-layer and NP-cell interaction will largely influence both the dispersion and binding rates, thus impact targeted delivery efficacy. In this paper, a particle-cell hybrid model is developed to model NP transport, dispersion, and binding dynamics in blood suspension. The motion and deformation of red blood cells is captured through the Immersed Finite Element Method. The motion and adhesion of individual NPs are tracked through Brownian adhesion dynamics. A mapping algorithm and an interaction potential function are introduced to consider the cell-particle collision. NP dispersion and binding rates are derived from the developed model under various rheology conditions. The influence of red blood cells, vascular flow rate, and particle size on NP distribution and delivery efficacy is characterized. A non-uniform NP distribution profile with higher particle concentration near the vessel wall is observed. Such distribution leads to over 50% higher particle binding rate compared to the case without RBC considered. The tumbling motion of RBCs in the core region of the capillary is found to enhance NP dispersion, with dispersion rate increases as shear rate increases. Results from this study contribute to the fundamental understanding and knowledge on how the particulate nature of blood influences NP delivery, which will provide mechanistic insights on the nanomedicine design for targeted drug delivery applications.