A human embryonic limb cell atlas resolved in space and time.

Human limbs emerge during the fourth post-conception week as mesenchymal buds, which develop into fully formed limbs over the subsequent months1. This process is orchestrated by numerous temporally and spatially restricted gene expression programmes, making congenital alterations in phenotype common2. Decades of work with model organisms have defined the fundamental mechanisms underlying vertebrate limb development, but an in-depth characterization of this process in humans has yet to be performed. Here we detail human embryonic limb development across space and time using single-cell and spatial transcriptomics. We demonstrate extensive diversification of cells from a few multipotent progenitors to myriad differentiated cell states, including several novel cell populations. We uncover two waves of human muscle development, each characterized by different cell states regulated by separate gene expression programmes, and identify musculin (MSC) as a key transcriptional repressor maintaining muscle stem cell identity. Through assembly of multiple anatomically continuous spatial transcriptomic samples using VisiumStitcher, we map cells across a sagittal section of a whole fetal hindlimb. We reveal a clear anatomical segregation between genes linked to brachydactyly and polysyndactyly, and uncover transcriptionally and spatially distinct populations of the mesenchyme in the autopod. Finally, we perform single-cell RNA sequencing on mouse embryonic limbs to facilitate cross-species developmental comparison, finding substantial homology between the two species.

Blood and immune development in human fetal bone marrow and Down syndrome.

Haematopoiesis in the bone marrow (BM) maintains blood and immune cell production throughout postnatal life. Haematopoiesis first emerges in human BM at 11-12 weeks after conception1,2, yet almost nothing is known about how fetal BM (FBM) evolves to meet the highly specialized needs of the fetus and newborn. Here we detail the development of FBM, including stroma, using multi-omic assessment of mRNA and multiplexed protein epitope expression. We find that the full blood and immune cell repertoire is established in FBM in a short time window of 6-7 weeks early in the second trimester. FBM promotes rapid and extensive diversification of myeloid cells, with granulocytes, eosinophils and dendritic cell subsets emerging for the first time. The substantial expansion of B lymphocytes in FBM contrasts with fetal liver at the same gestational age. Haematopoietic progenitors from fetal liver, FBM and cord blood exhibit transcriptional and functional differences that contribute to tissue-specific identity and cellular diversification. Endothelial cell types form distinct vascular structures that we show are regionally compartmentalized within FBM. Finally, we reveal selective disruption of B lymphocyte, erythroid and myeloid development owing to a cell-intrinsic differentiation bias as well as extrinsic regulation through an altered microenvironment in Down syndrome (trisomy 21).

Step-down multiple testing procedures for the overall population and partitioning subgroups.

Multiple comparisons procedures are described for two-armed studies where there is a primary hypothesis and one or more ordered secondary hypotheses in the scenario where the objective is to test for an effect on the overall population and/or nonoverlapping subgroups that partition the population. This scenario arises when the subgroups are defined by disease etiology or by other patient characteristics such as genetic factors, age, sex, or race, and the treatment may have differential effects in the subgroups. The procedures described control the family-wise error rate in the strong sense at a specified level α.

Evaluating Sepsis Bundle Compliance as a Predictor for Patient Outcomes at a Community Hospital: A Retrospective Study.

BACKGROUND: Clinicians are encouraged to use the Centers for Medicare & Medicaid Services early management bundle for severe sepsis and septic shock (SEP-1); however, it is unclear whether this process measure improves patient outcomes. PURPOSE: The purpose of this study was to evaluate whether compliance with the SEP-1 bundle is a predictor of hospital mortality, length of stay (LOS), and intensive care unit LOS at a suburban community hospital. METHODS: A retrospective observational study was conducted. RESULTS: A total of 577 patients were included in the analysis. Compliance with the SEP-1 bundle was not a significant predictor for patient outcomes. CONCLUSIONS: SEP-1 compliance may not equate with quality of health care. Efforts to comply with SEP-1 may help organizations develop systems and structures that improve patient outcomes. Health care leaders should evaluate strategies beyond SEP-1 compliance to ensure continuous improvement of outcomes for patients experiencing sepsis.

Engaging Emergency Nurses in Strategies to Address the Social Determinants of Health.

INTRODUCTION: For patients with social needs, emergency departments can be an essential bridge between the health care system and the community. Emergency nurses' knowledge of and engagement in this work need to be examined to ensure that efforts for social determinants of health screening and the resulting community connections are effective. However, there is limited research in this area of nursing practice. The purpose of this study is to describe emergency nurses' knowledge about social needs in their community, assess their knowledge of existing community resources, and examine their perceived confidence to respond to the social needs of their patients. METHODS: A cross-sectional survey was conducted with 243 nurses employed in a large regional health care system. Data were collected using an adapted 81-item social determinants of health survey instrument to measure knowledge of social determinants of health, confidence, and frequency of discussing social determinants of health with emergency department patients and awareness of social resources available in the community. Survey participants were asked about barriers to incorporating social determinants of health into their emergency department workflow and to provide general demographic information. Descriptive statistics were used to analyze study results. RESULTS: Most of the 243 emergency nurse participants believed that addressing social determinants of health was important and that emergency nurses should be involved in issues around social determinants of health. However, most nurses reported limited knowledge about social determinants of health and had very limited knowledge about the resources available in their community to help patients with needs related to food, housing, medical care, and transportation. Nurses reported that although they know that their patients are unlikely to ask for help with social needs during an emergency department visit, they are still unlikely to ask their patients about social needs owing to low confidence about having social needs conversations, limited time, and competing care priorities. Participants advocated for greater case manager presence. Feeling connected to the community was significantly correlated to increased knowledge, confidence, and likelihood to ask about social needs (P < .05). DISCUSSION: The emergency department is a logical place for screening for social determinants of health and connecting patients with social needs to community resources. Emergency nurses included in this study acknowledged that they want to address the social needs of their patients but reported that they lack knowledge about both social determinants of health and more importantly about the resources available to help patients with social needs. In general, they did not feel confident discussing social determinants of health with their patients in the emergency department and are unlikely to ask about social needs. Barriers to screening include time, competing care priorities, and lack of knowledge and support needed from case managers. Findings from this study have implications for supporting emergency nurses employed in institutions that seek to address social influences of health for the patients in their communities.

Intrarater and Interrater Reliability of Radiographic Characteristics in Skeletally Immature Patients With Anterior Cruciate Ligament Tears: A PLUTO Study Group Reliability Study.

BACKGROUND: Radiographic measurements of limb alignment in skeletally immature patients with anterior cruciate ligament (ACL) tears are frequently used for surgical decision-making, preoperative planning, and postoperative monitoring of skeletal growth. However, the interrater and intrarater reliability of these radiographic characteristics in this patient population is not well documented. HYPOTHESIS: Excellent reliability across 4 raters will be demonstrated for all digital measures of length, coronal plane joint orientation angles, mechanical axis, and tibial slope in skeletally immature patients with ACL tears. STUDY DESIGN: Cohort study (diagnosis). METHODS: Three fellowship-trained orthopaedic surgeons and 1 medical student performed 2 rounds of radiographic measurements on digital imaging (lateral knee radiographs and long-leg radiographs) of skeletally immature patients with ACL tears. Intrarater and interrater reliability for continuous radiographic measurements was assessed with intraclass correlation coefficients (ICCs) across 4 raters with 95% CIs for affected and unaffected side measurements. Interrater reliability analysis used an ICC (2, 4) structure and intrarater reliability analysis used an ICC (2, 1) structure. A weighted kappa coefficient was calculated for ordinal variables along with 95% CIs for both interrater and intrarater reliability. Agreement statistic interpretations are based on scales described by Fleiss, and Cicchetti and Sparrow: <0.40, poor; 0.40 to 0.59, fair; 0.60 to 0.74, good; and >0.74, excellent. RESULTS: Radiographs from a convenience sample of 43 patients were included. Intrarater reliability was excellent for nearly all measurements and raters. Interrater reliability was also excellent for nearly all reads for all measurements. CONCLUSION: Radiographic reliability of long-leg radiographs and lateral knee x-rays in skeletally immature children with ACL tears is excellent across nearly all measures and raters and can be obtained and interpreted as reliable and reproducible means to measure limb length and alignment. LEVEL OF EVIDENCE: Level III.

A Survey on Optimization Techniques for Edge Artificial Intelligence (AI).

Artificial Intelligence (Al) models are being produced and used to solve a variety of current and future business and technical problems. Therefore, AI model engineering processes, platforms, and products are acquiring special significance across industry verticals. For achieving deeper automation, the number of data features being used while generating highly promising and productive AI models is numerous, and hence the resulting AI models are bulky. Such heavyweight models consume a lot of computation, storage, networking, and energy resources. On the other side, increasingly, AI models are being deployed in IoT devices to ensure real-time knowledge discovery and dissemination. Real-time insights are of paramount importance in producing and releasing real-time and intelligent services and applications. Thus, edge intelligence through on-device data processing has laid down a stimulating foundation for real-time intelligent enterprises and environments. With these emerging requirements, the focus turned towards unearthing competent and cognitive techniques for maximally compressing huge AI models without sacrificing AI model performance. Therefore, AI researchers have come up with a number of powerful optimization techniques and tools to optimize AI models. This paper is to dig deep and describe all kinds of model optimization at different levels and layers. Having learned the optimization methods, this work has highlighted the importance of having an enabling AI model optimization framework.

Convergence of Artificial Intelligence and Neuroscience towards the Diagnosis of Neurological Disorders-A Scoping Review.

Artificial intelligence (AI) is a field of computer science that deals with the simulation of human intelligence using machines so that such machines gain problem-solving and decision-making capabilities similar to that of the human brain. Neuroscience is the scientific study of the struczture and cognitive functions of the brain. Neuroscience and AI are mutually interrelated. These two fields help each other in their advancements. The theory of neuroscience has brought many distinct improvisations into the AI field. The biological neural network has led to the realization of complex deep neural network architectures that are used to develop versatile applications, such as text processing, speech recognition, object detection, etc. Additionally, neuroscience helps to validate the existing AI-based models. Reinforcement learning in humans and animals has inspired computer scientists to develop algorithms for reinforcement learning in artificial systems, which enables those systems to learn complex strategies without explicit instruction. Such learning helps in building complex applications, like robot-based surgery, autonomous vehicles, gaming applications, etc. In turn, with its ability to intelligently analyze complex data and extract hidden patterns, AI fits as a perfect choice for analyzing neuroscience data that are very complex. Large-scale AI-based simulations help neuroscientists test their hypotheses. Through an interface with the brain, an AI-based system can extract the brain signals and commands that are generated according to the signals. These commands are fed into devices, such as a robotic arm, which helps in the movement of paralyzed muscles or other human parts. AI has several use cases in analyzing neuroimaging data and reducing the workload of radiologists. The study of neuroscience helps in the early detection and diagnosis of neurological disorders. In the same way, AI can effectively be applied to the prediction and detection of neurological disorders. Thus, in this paper, a scoping review has been carried out on the mutual relationship between AI and neuroscience, emphasizing the convergence between AI and neuroscience in order to detect and predict various neurological disorders.

Full Study Report of Andexanet Alfa for Bleeding Associated with Factor Xa Inhibitors.

BACKGROUND: Andexanet alfa is a modified recombinant inactive form of human factor Xa developed for reversal of factor Xa inhibitors. METHODS: We evaluated 352 patients who had acute major bleeding within 18 hours after administration of a factor Xa inhibitor. The patients received a bolus of andexanet, followed by a 2-hour infusion. The coprimary outcomes were the percent change in anti-factor Xa activity after andexanet treatment and the percentage of patients with excellent or good hemostatic efficacy at 12 hours after the end of the infusion, with hemostatic efficacy adjudicated on the basis of prespecified criteria. Efficacy was assessed in the subgroup of patients with confirmed major bleeding and baseline anti-factor Xa activity of at least 75 ng per milliliter (or ≥0.25 IU per milliliter for those receiving enoxaparin). RESULTS: Patients had a mean age of 77 years, and most had substantial cardiovascular disease. Bleeding was predominantly intracranial (in 227 patients [64%]) or gastrointestinal (in 90 patients [26%]). In patients who had received apixaban, the median anti-factor Xa activity decreased from 149.7 ng per milliliter at baseline to 11.1 ng per milliliter after the andexanet bolus (92% reduction; 95% confidence interval [CI], 91 to 93); in patients who had received rivaroxaban, the median value decreased from 211.8 ng per milliliter to 14.2 ng per milliliter (92% reduction; 95% CI, 88 to 94). Excellent or good hemostasis occurred in 204 of 249 patients (82%) who could be evaluated. Within 30 days, death occurred in 49 patients (14%) and a thrombotic event in 34 (10%). Reduction in anti-factor Xa activity was not predictive of hemostatic efficacy overall but was modestly predictive in patients with intracranial hemorrhage. CONCLUSIONS: In patients with acute major bleeding associated with the use of a factor Xa inhibitor, treatment with andexanet markedly reduced anti-factor Xa activity, and 82% of patients had excellent or good hemostatic efficacy at 12 hours, as adjudicated according to prespecified criteria. (Funded by Portola Pharmaceuticals; ANNEXA-4 ClinicalTrials.gov number, NCT02329327.).

Cold and exogenous calcium alter Allium fistulosum cell wall pectin to depress intracellular freezing temperatures.

De-methyl esterification of homogalacturonan and subsequent cross-linking with Ca2+ is hypothesized to enhance the freezing survival of cold acclimated plants by reducing the porosity of primary cell walls. To test this theory, we collected leaf epidermal peels from non- (23/18 °C) and cold acclimated (2 weeks at 12/4 °C) Japanese bunching onion (Allium fistulosum L.). Cold acclimation enhanced the temperature at which half the cells survived freezing injury by 8 °C (LT50 =-20 °C), and reduced tissue permeability by 70-fold compared with non-acclimated epidermal cells. These effects were associated with greater activity of pectin methylesterase (PME) and a reduction in the methyl esterification of homogalacturonan. Non-acclimated plants treated with 50 mM CaCl2 accumulated higher concentrations of galacturonic acid, Ca2+ in the cell wall, and a lower number of visible cell wall pores compared with that observed in cold acclimated plants. Using cryo-microscopy, we observed that 50 mM CaCl2 treatment did not lower the LT50 of non-acclimated cells, but reduced the lethal intracellular ice nucleation to temperatures observed in cold acclimated epidermal cells. We postulate that the PME-homogalacturonan-mediated reduction in cell wall porosity is integral to intracellular freezing avoidance strategies in cold acclimated herbaceous cells.

Group sequential design for randomized trials using "first hitting time" model.

Group sequential design (GSD) has become a popular choice in recent clinical trials as it improves trial efficiency by providing options for early termination. The implementation of traditional tests for survival analysis (eg, the log-rank test and the Cox proportional hazard (PH) model) in the GSD setting has been widely discussed. The PH assumption is required for conventional (sequential) design, it is, however, often violated in practice. As an alternative, some generalized tests have been proposed (eg, the Max-Combo test) and their efficacies have been established. In this article, we explore the application of a more flexible, "first hitting time" based threshold regression (TR) model to GSD. TR assumes that subjects' health status is a latent (unobservable) process, and the clinical event of interest occurs when the latent health process hits a pre-specified boundary. The simulation results supported our findings that, in most cases, this comparable new method can successfully control type I error while providing higher early stopping opportunities in the sequential design, even when non-proportional hazard presents.

Theileriosis in naturally infected roan antelope (Hippotragus equinus).

Cases of Theileria-associated mortality are rarely reported in African wild artiodactyls. Descriptions of lesions are limited, particularly in endangered hippotraginids. Here, we analyzed retrospectively the gross and histologic findings in 55 roan antelope (Hippotragus equinus) with fatal natural theileriosis. The most frequently recorded gross findings in 40 cases were widespread petechiae and ecchymoses (72.5%), probable anemia (67.5%), icterus (60%), splenomegaly (60%), hepatomegaly (52.5%), and pulmonary edema (50%). Histologic lesions in 34 cases were characterized by multi-organ infiltrates of parasitized and nonparasitized mononuclear leukocytes (MLs), and fewer multinucleate giant cells (MNGCs). Liver, lung, kidney, adrenal gland, and heart were most consistently infiltrated, followed by spleen and lymph nodes. Leukocytes were phenotyped in lung, liver, kidney, and heart specimens from 16 cases, using immunohistochemistry to detect CD20, CD3, myeloid/histiocyte antigen (MAC387), IBA-1, and CD204 surface receptors. A roan polyclonal anti-Theileria sp. (sable) antibody was applied to the same tissues to identify intraleukocytic parasite antigens. Similar proportions of intravascular and extravascular IBA-1-, CD204-, and MAC387-reactive putative monocyte-macrophages and fewer CD3-positive putative T-lymphocytes were identified in all organs, especially the lungs in infected roan. CD20-positive putative B-lymphocytes were significantly scarcer than in uninfected controls. Intraleukocytic Theileria parasites labeled consistently in affected tissues. Some parasitized and nonparasitized MLs and the MNGCs failed to label with selected leukocyte markers. Fatal theileriosis in roans may largely be the result of multi-organ monocyte-macrophage activation with associated tissue injury and overwhelming systemic inflammation. The identity of the parasitized leukocytes and characteristics of the lymphohistiocytic response require further clarification in roans.

Co-establishing an infrastructure for routine data collection to address disparities in infant mortality: planning and implementation.

BACKGROUND: Efforts to address infant mortality disparities in Ohio have historically been adversely affected by the lack of consistent data collection and infrastructure across the community-based organizations performing front-line work with expectant mothers, and there is no established template for implementing such systems in the context of diverse technological capacities and varying data collection magnitude among participating organizations. METHODS: Taking into account both the needs and limitations of participating community-based organizations, we created a data collection infrastructure that was refined by feedback from sponsors and the organizations to serve as both a solution to their existing needs and a template for future efforts in other settings. RESULTS: By standardizing the collected data elements across participating organizations, integration on a scale large enough to detect changes in a rare outcome such as infant mortality was made possible. Datasets generated through the use of the established infrastructure were robust enough to be matched with other records, such as Medicaid and birth records, to allow more extensive analysis. CONCLUSION: While a consistent data collection infrastructure across multiple organizations does require buy-in at the organizational level, especially among participants with little to no existing data collection experience, an approach that relies on an understanding of existing barriers, iterative development, and feedback from sponsors and participants can lead to better coordination and sharing of information when addressing health concerns that individual organizations may struggle to quantify alone.

Accounting for delayed entry into observational studies and clinical trials: length-biased sampling and restricted mean survival time.

Individuals in many observational studies and clinical trials for chronic diseases are enrolled well after onset or diagnosis of their disease. Times to events of interest after enrollment are therefore residual or left-truncated event times. Individuals entering the studies have disease that has advanced to varying extents. Moreover, enrollment usually entails probability sampling of the study population. Finally, event times over a short to moderate time horizon are often of interest in these investigations, rather than more speculative and remote happenings that lie beyond the study period. This research report looks at the issue of delayed entry into these kinds of studies and trials. Time to event for an individual is modelled as a first hitting time of an event threshold by a latent disease process, which is taken to be a Wiener process. It is emphasized that recruitment into these studies often involves length-biased sampling. The requisite mathematics for this kind of sampling and delayed entry are presented, including explicit formulas needed for estimation and inference. Restricted mean survival time (RMST) is taken as the clinically relevant outcome measure. Exact parametric formulas for this measure are derived and presented. The results are extended to settings that involve study covariates using threshold regression methods. Methods adapted for clinical trials are presented. An extensive case illustration for a clinical trial setting is then presented to demonstrate the methods, the interpretation of results, and the harvesting of useful insights. The closing discussion covers a number of important issues and concepts.

Effects of Therapeutic Ultrasound on Growth Plates: A Systematic Review.

PURPOSE: The aim of this systematic review was to evaluate studies reporting on the effects of therapeutic ultrasound on the physis. SUMMARY OF KEY POINTS: Eight studies were included in the final analysis, all of which were animal studies. At higher doses, studies found skin and bone necrosis and inhibition of growth, while in lower doses some studies found that ultrasound had a transient stimulatory effect on growth, increased thickness of the hypertrophic zone, and increased thickness of the whole growth plate. Overall, experimental evidence in animal models suggests that therapeutic ultrasound, even at low doses, might induce microscopic changes to the histology of the growth plate. CONCLUSION: While we found no reports of growth disturbance in humans, given the histological changes found in animal studies, the current limited literature seems to support the recommendation that the application of therapeutic ultrasound around the physis should be avoided.

Days alive out of hospital in heart failure: Insights from the PARADIGM-HF and CHARM trials.

BACKGROUND: An endpoint that has received some attention in recent cardiovascular trials is 'days alive and out of hospital' (DAOH). Percent DAOH is a natural extension of DAOH that adjusts for differences in length of follow-up. This endpoint measure incorporates mortality and morbidity together in a way that has the potential to give more insight regarding treatment effects compared to conventional time-to-event endpoints. Other advantages of this measure include the relative ease of collection and interpretation. However, research on how to analyze this measure is still limited. METHODS: We propose using the one-inflated beta model to analyze percent DAOH. This model is appropriate for highly left-skewed data with a large proportion of boundary values. Data from the Prospective Comparison of ARNI [Angiotensin Receptor-Neprilysin Inhibitor] with ACEI [Angiotensin-Converting-Enzyme Inhibitor] to Determine Impact on Global Mortality and Morbidity in Heart Failure Trial (PARADIGM-HF) and Candesartan in Heart Failure Assessment of Reduction in Mortality and morbidity (CHARM) trials are used to illustrate this method. RESULTS: Statistically significant differences in percent DAOH were observed for PARADIGM-HF and CHARM in favor of treatment. In PARADIGM-HF, treatment with sacubitril plus valsartan increased DAOH on average by 11 days (95% CI: 1.4-20.9 days) and increased percent DAOH by 1.64% at a fixed follow-up length of 1,000 days (95% CI: 0.61%- 2.67%). For the CHARM overall program, the candesartan group has 1.79% more DAOH (95% CI: 0.91%- 2.68%). CONCLUSION: DAOH, and especially percent DAOH, can enhance our understanding of treatment effects in future cardiovascular trials, and the one-inflated beta model is an appropriate choice for its analysis.

Identifying Opportunities to Strengthen the Public Health Informatics Infrastructure: Exploring Hospitals' Challenges with Data Exchange.

Policy Points Even though most hospitals have the technological ability to exchange data with public health agencies, the majority continue to experience challenges. Most challenges are attributable to the general resources of public health agencies, although workforce limitations, technology issues such as a lack of data standards, and policy uncertainty around reporting requirements also remain prominent issues. Ongoing funding to support the adoption of technology and strengthen the development of the health informatics workforce, combined with revising the promotion of the interoperability scoring approach, will likely help improve the exchange of electronic data between hospitals and public health agencies. CONTEXT: The novel coronavirus 2019 (COVID-19) pandemic has highlighted significant barriers in the exchange of essential information between hospitals and local public health agencies. Thus it remains important to clarify the specific issues that hospitals may face in reporting to public health agencies to inform focused approaches to improve the information exchange for the current pandemic as well as ongoing public health activities and population health management. METHODS: This study uses cross-sectional data of acute-care, nonfederal hospitals from the 2017 American Hospital Association Annual Survey and Information Technology supplement. Guided by the technology-organization-environment framework, we coded the responses to a question regarding the challenges that hospitals face in submitting data to public health agencies by using content analysis according to the type of challenge (i.e., technology, organization, or environment), responsible entity (i.e., hospital, public health agency, vendor, multiple), and the specific issue described. We used multivariable logistic and multinomial regression to identify characteristics of hospitals associated with experiencing the types of challenges. FINDINGS: Our findings show that of the 2,794 hospitals in our analysis, 1,696 (61%) reported experiencing at least one challenge in reporting health data to a public health agency. Organizational issues were the most frequently reported type of challenge, noted by 1,455 hospitals. The most common specific issue, reported by 1,117 hospitals, was the general resources of public health agencies. An advanced EHR system and participation in a health information exchange both decreased the likelihood of not reporting experiencing a challenge and increased the likelihood of reporting an organizational challenge. CONCLUSIONS: Our findings inform policy recommendations such as improving data standards, increasing funding for public health agencies to improve their technological capabilities, offering workforce training programs, and increasing clarity of policy specifications and reporting. These approaches can improve the exchange of information between hospitals and public health agencies.

Sample size adaptations and evaluation of pediatric study interpretability.

To extend marketing exclusivity, a drug manufacture is required by the Food and Drug Administration to conduct an interpretable study of approved drugs that may benefit pediatric patients. In return for conducting an interpretable study, the drug manufacturer is rewarded with an additional 6 months of marketing exclusivity. If the study design uses a fixed sample size and nothing is changed during the study, it is relatively easy to determine whether an interpretable study was conducted. However, if the sample size can be changed based on an unblinded interim analysis, it is difficult to answer the question of whether the study was interpretable. We investigate the optimal design from the manufacturers perspective and find the strategy for sample size adaptation that optimizes the utility including the chance of an interpretable study.

Impact of sample collection on prokaryotic and eukaryotic diversity of niche environments of the oil-sand mining impacted Athabasca River.

Microbial communities are an important aspect of overall riverine ecology; however, appreciation of the effects of anthropogenic activities on unique riverine microbial niches, and how the collection of these samples affects the observed diversity and community profile is lacking. We analyzed prokaryotic and eukaryotic communities from surface water, biofilms, and suspended load niches along a gradient of oil sands-related contamination in the Athabasca River (Alberta, Canada), with suspended load or particle-associated communities collected either via Kenney Sampler or centrifugation manifold. At the phylum level, different niche communities were highly similar to each other and across locations. However, there were significant differences in the abundance of specific genera among the different niches and across sampling locations. A generalized linear model revealed that use of the Kenney Sampler resulted in more diverse bacterial and eukaryotic suspended load community than centrifugal collection, though suspended load communities collected by any means remained stably diverse across locations. Although there was an influence of water quality parameters on community composition, all sampled sites support diverse bacterial and eukaryotic communities regardless of the degree of contamination, highlighting the need to look beyond ecological diversity as a means of assessing ecological perturbations, and consider collecting samples from multiple niche environments.

Investigation of the relationship between heart rate and functional class in pulmonary hypertension.

The utility of a non-linear mixed effects model to model heart rate is examined. The heart rate acceleration is derived as a parameter from this model. The relationship between different potential measures of disease severity including heart rate acceleration is examined. Our study is focused on heart rate variability (HRV), heart rate acceleration (HRA), oxygen saturation (SaO2) and the six-minute walk distance (6MWD) as well as their relationship to WHO functional class. The results and conclusions are derived from data were collected by the Children Hospital of Colorado.