Forecasting hospital bed availability using computer simulation and neural networks

The success of hospitals in treating patients and staying in business relies on their efficient use of resources. In particular, the utilization of hospital beds is a critical concern, since over-crowding will result in delays or transfers of patients, and under-utilization will result in lost opportunity to treat patients and generate profit. To this end, hospital decision makers must have reliable forecasts of patient demand and bed availability. The objective of this thesis was to create a general method to forecast the availability of hospital beds in the short term, up to 2 days into the future. Specifically, this thesis employed a computer simulation model of the hospital and a time-dependent neural network to learn from the simulated model and forecast the availability of beds. The computer simulation model was found to be well suited to the task of describing a general hospital system and creating training data for a neural network. The neural network was found to provide accurate performance in predicting bed availability in the short term. The network incorporated the effect of time explicitly to capture the non-stationary behavior of hospital systems. These findings have a number of implications that will be discussed

Evaluation of a silver-impregnated coating to inhibit colonization of orthopaedic implants by biofilm forming methicillin-resistant Staphylococcus pseudintermedius.

OBJECTIVES: To evaluate the in vitro antibacterial activity of a silver-impregnated coating against a biofilm-forming strain of methicillin-resistant Staphylococcus pseudintermedius (MRSP). METHODS: A clinical MRSP isolate sourced from a failed canine knee implant was evaluated for biofilm production and used in the present study. Using a standard test method and a clinically approved titanium substrate, the antimicrobial activity of a novel silver plasma coating was determined at two times: five minutes after inoculation of the specimens (T0) and after 24 hours of incubation (T24). Scanning electron microscopy was used to evaluate the biofilm formation on specimens. RESULTS: The tested clinical MRSP isolate was classified as a strong biofilm producer. The silver coating significantly reduced the MRSP growth more than four log steps compared to the non-coated specimens and showed more than 99.98% reduction in the number of colony forming units after 24 hours. Scanning electron microscopy images revealed that silver-coated surfaces did not manifest detectable biofilm, while biofilm formation was readily observed on the control specimens. CLINICAL SIGNIFICANCE: The silver coating exhibited excellent activity against the multidrug resistant biofilm-forming MRSP isolate. The next stage of this work will involve testing in an animal model of orthopaedic infection. Positive results from animal studies would support the introduction of the silver plasma coating as a new strategy for preventing implant contamination, biofilm formation, and surgical infection in dogs undergoing orthopaedic surgery.The authors thank Bio-Gate AG for providing the Ag/SiOxCy plasma coating on the test discs.This is the author accepted manuscript. The final version is available from Schattauer Publishers via http://dx.doi.org/10.3415/VCOT-15-08-013

Investigation of flow through a computationally generated packed column using CFD and additive layer manufacturing

Preprint submitted to Computers and Chemical Engineering 18 March 2014. © The AuthorsThe version of record is available from the publisher via doi:10.1016/j.compchemeng.2014.04.005.When analysing packed beds using CFD approaches, producing an accurate geometry is often challenging. Often a computational model is produced from non-invasive imaging of the packed bed using 3d MRI or μ-CT. This work pioneers the exact reverse of this, by creating a physical bed from the computational model using Additive Layer Manufacturing (ALM). The paper focuses on both experimental analysis and computational analysis of packed columns of spheres. A STL file is generated of a packed column formed using a Monte-Carlo packing algorithm, and this is meshed and analysed using Computational Fluid Dynamics. In addition to this, a physical model is created using ALM on a 3d printer. This allows us to analyse the identical bed geometry both computationally and experimentally and compare the two. Pressure drop and flow patterns are analysed within the bed in detail. © 2014 Elsevier Ltd

Islands of conformational stability for Filopodia

Filopodia are long, thin protrusions formed when bundles of fibers grow outwardly from a cell surface while remaining closed in a membrane tube. We study the subtle issue of the mechanical stability of such filopodia and how this depends on the deformation of the membrane that arises when the fiber bundle adopts a helical configuration. We calculate the ground state conformation of such filopodia, taking into account the steric interaction between the membrane and the enclosed semiflexible fiber bundle. For typical filopodia we find that a minimum number of fibers is required for filopodium stability. Our calculation elucidates how experimentally observed filopodia can obviate the classical Euler buckling condition and remain stable up to several tens of . We briefly discuss how experimental observation of the results obtained in this work for the helical-like deformations of enclosing membrane tubes in filopodia could possibly be observed in the acrosomal reactions of the sea cucumber Thyone, and the horseshoe crab Limulus. Any realistic future theories for filopodium stability are likely to rely on an accurate treatment of such steric effects, as analysed in this work

Experience with the Danish Mix-ELISA in the United States

This article details some of our experiences with Danish mix-ELISA (DME) testing on herds in the United States. In contrast to Denmark, clinical outbreaks of Salmonella Choleraesuis occur in the United States. We examine the appropriateness of the current cut-off of OD%\u3e=40 for U.S. herds by examining serum and fecal samples collected from individual pigs and tested with the DME and culture, respectively. We report the estimated sensitivity and specificity of the DME using the original and possibly modified cut-off values. The 30% cutoff was deemed optimal with a sensitivity of .57 (.45, .82) and a specificity of .84 (.68, .98) for the first set of samples and .69 (.49, .93) and .63 (.53, .76) for the second set of samples. A major use of these tests is for monitoring herds for Salmonella exposure over time. Information on the sensitivity and specificity of the DME is helpful in determining how many animals in a herd to sample and how often

Species-specific calcite production reveals Coccolithus pelagicus as the key calcifier in the Arctic Ocean

Through the production and export of their calcite coccoliths, coccolithophores form a key component of the global carbon cycle. Despite this key role, very little is known about the biogeochemical role of different coccolithophore species in terms of calcite production, and how these species will respond to future climate change and ocean acidification. Here, we present the first study to estimate species-specific calcite production, from samples collected in the Arctic Ocean and subarctic Iceland Basin in June 2012. We show that although the coccolithophorid Coccolithus pelagicus comprised only a small fraction of the total community in terms of abundance (2%), our estimates indicate that it was the major calcite producer in the Arctic Ocean and Iceland Basin (57% of total calcite production). In contrast, Emiliania huxleyi formed 27% of the total abundance and was responsible for only 20% of the calcite production. That C. pelagicus was able to dominate calcite production was due to its relatively high cellular calcite content compared with the other species present. Our results demonstrate, for the first time, the importance of investigating the complete coccolithophore community when considering pelagic calcite production, as relatively rare but heavily calcified species such as C. pelagicus can be the key calcite producers in mixed communities. Therefore, the response of C. pelagicus to ocean acidification and climate change has the potential to have a major impact on carbon cycling within the North Atlantic and Arctic Ocean

Quality of life in restorative versus non-restorative resections for rectal cancer:systematic review

BACKGROUND: Low rectal cancers could be treated using restorative (anterior resection, AR) or non-restorative procedures with an end/permanent stoma (Hartmann’s, HE; or abdominoperineal excision, APE). Although the surgical choice is determined by tumour and patient factors, quality of life (QoL) will also influence the patient's future beyond cancer. This systematic review of the literature compared postoperative QoL between the restorative and non-restorative techniques using validated measurement tools. METHODS: The review was registered on PROSPERO (CRD42020131492). Embase and MEDLINE, along with grey literature and trials websites, were searched comprehensively for papers published since 2012. Inclusion criteria were original research in an adult population with rectal cancer that reported QoL using a validated tool, including the European Organization for Research and Treatment of Cancer QLQ-CR30, QLQ-CR29, and QLQ-CR38. Studies were included if they compared AR with APE (or HE), independent of study design. Risk of bias was assessed using the Risk Of Bias In Non-Randomized Studies of Interventions (ROBINS-I) tool. Outcomes of interest were: QoL, pain, gastrointestinal (GI) symptoms (stool frequency, flatulence, diarrhoea and constipation), and body image. RESULTS: Nineteen studies met the inclusion criteria with a total of 6453 patients; all papers were observational and just four included preoperative evaluations. There was no identifiable difference in global QoL and pain between the two surgical techniques. Reported results regarding GI symptoms and body image documented similar findings. The ROBINS-I tool highlighted a significant risk of bias across the studies. CONCLUSION: Currently, it is not possible to draw a firm conclusion on postoperative QoL, pain, GI symptoms, and body image following restorative or non-restorative surgery. The included studies were generally of poor quality, lacked preoperative evaluations, and showed considerable bias in the data

Experience with Danish mix-ELISA in the United States

This paper details some of our experiences with Danish mix-ELISA (DME) testing on herds in the United States. In contrast to Denmark, clinical outbreaks of Salmonella Choleraesuis occur in the U.S. We examine the appropriateness of the current cut-off of OD%\u3e=40 for U.S. herds by examining serum and fecal samples collected from individua l pigs and tested with the DME and culture, respectively. We report the estimated sensitivity and specificity of the DME using the original and possibly modified cut-off values. The 30% cutoff was deemed optimal with a sensitivity of .57 (.45,.82) and a specificity of .84 (.68,.98) for the first set of samples and .69(.49,.93) and .63(.53,.76) for the second set of samples. A major use of these tests is for monitoring herds for Salmonella exposure over time. Information on the sensitivity and specificity of the DME is helpful in determining how many animals in a herd to sample and how often