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Chantal E Holy,1,* Katherine A Corso,1,* Dawn E Bowden,2 Michael J Erb,2 Jill R Ruppenkamp,1 Sandra Coombs,3 John B Pracyk3 1Johnson & Johnson Medical Devices Companies, Medical Device Epidemiology and Real World Data Sciences, New Brunswick, NJ, USA; 2Johnson & Johnson Medical Devices Companies, Health Economics and Market Access, Raynham, MA, USA; 3DePuy Synthes, Raynham, MA, USA*These authors contributed equally to this workCorrespondence: Katherine A CorsoJohnson & Johnson Medical Devices Companies, Medical Device Epidemiology and Real World Data Sciences, 410 George Street, New Brunswick, NJ, 08901, USATel +1 508 977 6696Email kcorso1@its.jnj.comPurpose: Minimally invasive surgery (MIS) of the spine has been associated with favorable outcomes compared to open surgery. This study evaluated matched cohorts treated with MIS versus open posterior lumbar fusion for costs, payments, healthcare utilization and outcomes.Patients and Methods: This study used the Premier Healthcare and IBM® MarketScan® Commercial and Medicare Databases. Patients with posterior lumbar fusion from 2015 to 2018 were identified and categorized as “Open” or “MIS”. Cohorts were matched on patient and provider characteristics. Perioperative complications, hospital costs, healthcare utilization and post-operative outcomes and payments to providers were analyzed. Statistical significance was evaluated using T-tests and chi-square tests.Results: After matching, 2,388 Open and 796 MIS from PHD, and 415 Open and 83 MIS from MarketScan were included. Statistically significant differences between MIS versus Open were found for index hospital costs, $29,181 (SD: $14,363) versus $27,616 (SD: $13,822), p=0.01; length of stay, 2.94 (SD: 2.10) versus 3.15 (SD: 2.03) days, p=0.01; perioperative urinary tract infection, 1.01% and 2.09% (p=0.05); and 30-day risk of hematoma/hemorrhage, 19.28% versus 8.43%, p=0.02. There were observed, but statistically non-significant differences in additional perioperative or post-operative complications, home discharge, 90-day all-cause and spine-related readmission, and 90-day post-operative payments.Conclusion: Compared to Open, patients that underwent MIS had statistically significant lower length of stay, lower perioperative UTI, greater hospital costs, and higher 30-day risk of hematoma/hemorrhage. The differences observed in post-operative complications and payments and readmissions warrant further investigation in larger matched cohorts.Keywords: minimally invasive surgical procedures, database, spine, lumbar vertebrae, propensity score, health services research, health care costs

General rigid bead-rod theory yields uniquely the relation between macromolecular architecture and complex viscosity. For this, it relies on the analytical solution of the general diffusion equation for small-amplitude oscillatory shear flow of Bird et al. [Dynamics of Polymeric Liquids, 2nd ed. (Wiley, New York, 1987), Vols. 1–2]. Unfortunately, this general diffusion equation has yet to be solved for any other flow field. In this paper, we do so for steady-shear material functions, namely, viscosity and first normal stress coefficient. We, thus, explain the non-Newtonian behaviors of macromolecular suspensions of any axisymmetric design in steady-shear flow. [ABSTRACT FROM AUTHOR]

Microfluidic design, fabrication, and experiments have developed rapidly, leading to lab-on-chip separation or fractionation. In this work, we design a continuous concentrator for macromolecular solutions. Our design relies on the analytical solutions for orientational diffusion under laminar pressure-driven slot flow through a microchannel [W. Stasiak and C. Cohen, "Dilute solutions of macromolecules in a rectilinear Poiseuille flow," J. Chem. Phys. 78, 553 (1983)]. Using rigid dumbbell theory, we provide analytical solutions for the design of our microfluidic macromolecular hydrodynamic chromatography. We arrive at our design through the use of well-known confinement-driven composition profiles. Using a pair of razor-sharp blades, our design separates the slot flow into a symmetric core inner slot (concentrated) between two outer slots (diluted). We discover a minimum dimensionless blade leading edge separation for complete fractionation, and that this decreases with confinement and also decreases with dimensionless shear rate. [ABSTRACT FROM AUTHOR]

One good way to explain the elasticity of a polymeric liquid is to just consider the orientation distribution of the macromolecules. When exploring how macromolecular architecture affects the elasticity of a polymeric liquid, we find the general rigid bead–rod theory to be both versatile and accurate. This theory sculpts macromolecules using beads and rods. Whereas beads represent points of Stokes flow resistances, the rods represent rigid separations. In this way, how the shape of the macromolecule affects its rheological behavior in suspension is determined. Until recently, general rigid bead–rod theory has neglected interferences of the Stokes flow velocity profiles between nearby beads. We call these hydrodynamic interactions, and we here employ our new method for exploring how these interactions affect the complex viscosity of suspensions of multi-bead rods. These multi-bead rods are also called shish-kebabs. We use the center-to-center distance between adjacent beads as the characteristic length. We proceed analytically, beginning with a geometric expression for the shish-kebab bead positions. Our analytical solution for the complex viscosity presents as one for N = 3 , 5 , 6 , 7 , 8 , ... , one for N = 4 , and another for the rigid dumbbell, N = 2. We find that for shish-kebabs, hydrodynamic interactions (i) increase zero-shear viscosity, (ii) increase zero-shear first normal stress coefficient, (iii) decrease the real part of the dimensionless complex viscosity, and (iv) increase minus the dimensionless imaginary part. We find that the combination of (iii) and (iv) explains crossovers of the parts of the complex viscosity. We further find that for a monodisperse polystyrene solution, the general rigid bead–rod theory with hydrodynamic interaction, for both parts of the complex viscosity, provides stunning improvement over without. [ABSTRACT FROM AUTHOR]

Chains of mechanically interlocking or intersecting organic rings, called poly[ n ]catenanes, afford interesting opportunities to study the role of orientation in suspensions. We call poly[ 5 ]catenanes olympiadanes. In this work, we use general rigid bead-rod theory to arrive at general expressions, from first principles, for the complex viscosity of poly[ n ]catenane suspensions. General rigid bead-rod theory relies entirely on suspension orientation to explain the elasticity of the liquid. We obtain analytical expressions for the complex viscosity of poly[n]catenanes for both n even and odd, for both mechanically interlocking and intersecting rings, and for identically sized rings. We restrict our analysis to evenly spaced poly[n]catenanes of orthogonal adjacency. We find that the parts of the complex viscosity for intersecting and interlocking rings, when made dimensionless with the polymer contribution to the zero-shear viscosity, match. We find good agreement with the available complex viscosity measurements for molten intersecting polystyrene poly[1,3]catenanes, but not so for poly[2]catenanes. We next calculate space filling equilibrium structures of these poly[ 1 – 3 ]catenanes, only to discover that each polystyrene ring looks more like a bead. We find that, for these polystyrene poly[ n ]catenanes and for good agreement with the available complex viscosity measurements, the shish-kebab theory suffices. [ABSTRACT FROM AUTHOR]

The complex viscosity of planar star-branched polymers has been derived from general rigid bead-rod theory, but only for singly-beaded arms. Here, we explore the respective roles of branch functionality, arm length, and nonplanar arrangements, analytically from general rigid bead-rod theory. For nonplanar, we include polyhedral, both regular and irregular. Further, for all structures, we compare with and without the central bead. We fit the theory to complex viscosity measurements on polybutadiene solutions, one quadrafunctional star-branched, the other unbranched, of the same molecular weight ( M w = 200 000 g / gmol). We learn that when general rigid bead-rod theory is applied to quadrafunctional polybutadiene, a slightly irregular center-beaded tetrahedron of interior angle 134° is required (with 1 360 000 g / gmol per bead) to describe its complex viscosity behavior. [ABSTRACT FROM AUTHOR]

Atomically thin flat sheets of carbon, called graphene, afford interesting opportunities to study the role of orientation in suspensions. In this work, we use general rigid bead-rod theory to arrive at general expressions from first principles for the complex viscosity of graphene suspensions. General rigid bead-rod theory relies entirely on suspension orientation to explain the elasticity of the liquid. We obtain analytical expressions for the complex viscosity of triangular and hexagonal graphene sheets of arbitrary size. We find good agreement with new complex viscosity measurements. [ABSTRACT FROM AUTHOR]

Whereas much is known about the complex viscosity of polymeric liquids, far less is understood about the behavior of this material function when macromolecules are confined. By confined, we mean that the gap along the velocity gradient is small enough to reorient the polymers. We examine classical analytical solutions [O. O. Park and G. G. Fuller, "Dynamics of rigid and flexible polymer chains in confined geometries. II. Time-dependent shear flow," J. Non-Newtonian Fluid Mech. 18, 111–122 (1985)] for a confined rigid dumbbell suspension in small-amplitude oscillatory shear flow. We test these analytical solutions against the measured effects of confinement on both parts of the complex viscosity of a carbopol suspension and three polystyrene solutions. From these comparisons, we find that both parts of the complex viscosity decrease with confinement and that macromolecular orientation explains this. We find the persistence length of macromolecular confinement, L p , to be independent of both λ ω and λ γ ̇ 0 . [ABSTRACT FROM AUTHOR]

Empirically, we find that the parametric plots of the imaginary vs real parts of the complex viscosity may depend neither on temperature nor on average molecular weight. Moreover, for a fixed polydispersity, these viscosity Cole–Cole curves amplify both rightward and upward with long-chain branching content. In this paper, we find that general rigid bead–rod theory [O. Hassager, "Kinetic theory and rheology of bead–rod models for macromolecular solutions. II. Linear unsteady flow properties," J. Chem. Phys. 60(10), 4001–4008 (1974)] can explain these rightward and upward amplifications. We explore the effects of branching along a straight chain in small-amplitude oscillatory shear flow. Specifically, we explore the number of branches, branch length, branch position, and branch distribution. [ABSTRACT FROM AUTHOR]

To assess how flow affects school structure and threat detection, startle response rates of solitary and small groups of giant danio Devario aequipinnatus to visual looming stimuli were compared in flow and no-flow conditions. The instantaneous position and heading of each D. aequipinnatus was extracted from high-speed videos. Behavioural results indicate that (1) school structure is altered in flow such that D. aequipinnatus orient upstream while spanning out in a crosswise direction, (2) the probability of at least one D. aequipinnatus detecting the visual looming stimulus is higher in flow than no flow for both solitary D. aequipinnatus and groups of eight D. aequipinnatus; however, (3) the probability of three or more individuals responding is higher in no flow than in flow. These results indicate a higher probability of stimulus detection in flow but a higher probability of internal transmission of information in no flow. Finally, results were well predicted by a computational model of collective fright response that included the probability of direct detection (based on signal detection theory) and indirect detection ( i.e. via interactions between group members) of threatening stimuli. This model provides a new theoretical framework for analysing the collective transfer of information among groups of fishes and other organisms. [ABSTRACT FROM AUTHOR]

Rheotaxis is a robust, multisensory behavior with many potential benefits for fish and other aquatic organisms. Visual (optic flow) cues appear to be sufficient for rheotaxis, but other sensory cues can clearly compensate for the loss of vision. Nevertheless, the nature of multisensory interactions and the relative contributions of different senses under varying conditions are poorly understood - largely because there is so little description of the actual behavior. Here, we examined the effects of different flow speeds and different sensory conditions on the spatiotemporal dynamics of rheotaxis. Although the overall ability of giant danio (Devario aequipinnatus) to head upstream is largely unaffected by either unimodal or bimodal deprivation of visual and/or lateral line senses, the spatiotemporal form of the behavior is altered in subtle ways. When deprived of vision, fish move further upstream, but the angular accuracy of the upstream heading is reduced. In addition, visually deprived fish exhibit left/right sweeping movements near the upstream barrier at low flow speeds. Sweeping movements are abolished when these fish are additionally deprived of lateral line information. These results indicate that fish adopt different sensorimotor strategies to compensate for the loss of one or more senses and that the nature of multisensory interactions is a complex function of flow speed. [ABSTRACT FROM AUTHOR]

Oil shale processing produces an aqueous wastewater stream known as retort water. The fate of the organic content of retort water from the Stuart oil shale project (Gladstone, Queensland) is examined in a proposed packed bed treatment system consisting of a 1:1 mixture of residual shale from the retorting process and mining overburden. The retort water had a neutral pH and an average unfiltered TOC of 2,900 mg l-1. The inorganic composition of the retort water was dominated by NH4+. Only 40% of the total organic carbon (TOC) in the retort water was identifiable, and this was dominated by carboxylic acids. In addition to monitoring influent and effluent TOC concentrations, CO2 evolution was monitored on line by continuous measurements of headspace concentrations and air flow rates. The column was run for 64 days before it blocked and was dismantled for analysis. Over 98% of the TOC was removed from the retort water. Respirometry measurements were confounded by CO2 production from inorganic sources. Based on predictions with the chemical equilibrium package PHREEQE, approximately 15% of the total CO2 production arose from the reaction of NH4+ with carbonates. The balance of the CO2 production accounted for at least 80% of the carbon removed from the retort water. Direct measurements of solid organic carbon showed that approximately 20% of the influent carbon was held-up in the top 20cm of the column. Less than 20% of this held-up carbon was present as either biomass or as adsorbed species. Therefore, the column was ultimately blocked by either extracellular polymeric substances or by a sludge that had precipitated out of the retort water. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to provide the core description of the modelling exercise within the Shelf Edge Advection Mortality And Recruitment (SEAMAR) programme. An individual-based model (IBM) was developed for the prediction of year-to-year survival of the early life-history stages of mackerel (Scomber scombrus) in the eastern North Atlantic. The IBM is one of two components of the model system. The first component is a circulation model to provide physical input data for the IBM. The circulation model is a geographical variant of the HAMburg Shelf Ocean Model (HAMSOM). The second component is the IBM, which is an i-space configuration model in which large numbers of individuals are followed as discrete entities to simulate the transport, growth and mortality of mackerel eggs, larvae and post-larvae. Larval and post-larval growth is modelled as a function of length, temperature and food distribution; mortality is modelled as a function of length and absolute growth rate. Each particle is considered as a super-individual representing 106 eggs at the outset of the simulation, and then declining according to the mortality function. Simulations were carried out for the years 1998–2000. Results showed concentrations of particles at Porcupine Bank and the adjacent Irish shelf, along the Celtic Sea shelf-edge, and in the southern Bay of Biscay. High survival was observed only at Porcupine and the adjacent shelf areas, and, more patchily, around the coastal margin of Biscay. The low survival along the shelf-edge of the Celtic Sea was due to the consistently low estimates of food availability in that area. [ABSTRACT FROM AUTHOR]

An individual-based model (IBM) for the simulation of year-to-year survival during the early life-history stages of the north-east Atlantic stock of mackerel (Scomber scombrus) was developed within the EU funded Shelf-Edge Advection, Mortality and Recruitment (SEAMAR) programme. The IBM included transport, growth and survival and was used to track the passive movement of mackerel eggs, larvae and post-larvae and determine their distribution and abundance after approximately 2 months of drift. One of the main outputs from the IBM, namely distributions and numbers of surviving post-larvae, are compared with field data as recruit (age-0/age-1 juveniles) distribution and abundance for the years 1998, 1999 and 2000. The juvenile distributions show more inter-annual and spatial variability than the modelled distributions of survivors; this may be due to the restriction of using the same initial egg distribution for all 3 yr of simulation. The IBM simulations indicate two main recruitment areas for the north-east Atlantic stock of mackerel, these being Porcupine Bank and the south-eastern Bay of Biscay. These areas correspond to areas of high juvenile catches, although the juveniles generally have a more widespread distribution than the model simulations. The best agreement between modelled data and field data for distribution (juveniles and model survivors) is for the year 1998. The juvenile catches in different representative nursery areas are totalled to give a field abundance index (FAI). This index is compared with a model survivor index (MSI) which is calculated from the total of survivors for the whole spawning season. The MSI compares favourably with the FAI for 1998 and 1999 but not for 2000; in this year, juvenile catches dropped sharply compared with the previous years but there was no equivalent drop in modelled survivors. [ABSTRACT FROM AUTHOR]

Examines the use of a electrophysiological recording technique to determine the moving speeds of prediators which was encoded by anterior lateral line nerve fibers. Properties of peripheral lateral line nerve fibers; Systems analysis of peripheral mechanisms; How the pressure gradient pattern produced by the moving sphere was characterised.

Fish eggs and larvae were analysed from 63 vertically stratified plankton hauls in the Irish Sea and southern North Sea. The dominant species were sprat (Sprattus sprattus), dragonet (Callionymus spp.), dab (Limanda limanda) and to a lesser extent rockling species, sandeel (Ammodytes spp.), whiting (Merlangius merlangus) and flounder (Platichthys flesus). There was little difference between species in the vertical distribution of either eggs or larvae. Most were concentrated in the upper 50 m of the water column, eggs in progressively increasing numbers towards the surface and larvae with a sub-surface peak at a depth of 10–15 m. The vertical distribution of eggs extended deeper in the water column than larvae, possibly due to some combination of eggs being spawned deeper and their passive susceptibility to turbulent mixing. There were no significant differences between day and night distributions and under mixed or isothermal conditions. [ABSTRACT FROM PUBLISHER]

Larvae of sprat (Sprattus sprattus) from mixed and stratified water column sites in the German Bight of the North Sea were assessed for nutritional condition by analysis of total carbon and nitrogen and the lipid fractions triacylglycerol (TAG), cholesterol, and polar lipids. There was no indication of any significant variation in condition index related to diel sampling periodicity, based either on percentage carbon composition or TAG/cholesterol ratio. Inclusion of growth data from otolith ring counts with the carbon and lipid results identified larvae at 9-10 mm in length as being in relatively poor condition. There was some evidence from carbon analysis to suggest that larvae in poor condition were more prevalent at the stratified site than the mixed; however, microzooplankton analysis showed mean food abundance for larvae was slightly higher at the mixed site. The results from the condition analyses and the validity of the methods is discussed in relation to studies of survival of fish larvae. [ABSTRACT FROM PUBLISHER]

A numerical circulation and transport model system was used to simulate the dispersion of larvae of blue whiting, Micromesistius poutassou (Risso) in the eastern North Atlantic. The area of the model extends from the northern Bay of Biscay to the Norwegian Sea and covers the shelf-edge and adjacent waters at a horizontal resolution of around 20 km in 16 vertical layers. Larval input data were based on the long-term mean distribution, abundance and seasonal occurrence of larvae, derived from historical information. The circulation model was run using tidal forcing and climatological density fields as well as both climatological meteorological forcing and actual six-hourly wind stress fields for 1994 and 1995. Transport from the main spawning areas to the west of the British Isles and north of Porcupine Bank was associated with currents along the shelf-edge and in the Rockall Trough. Tracers were either dispersed to the north and north-east along the shelf-edge, extending into the northern North Sea and Norwegian Sea, or were retained in the Rockall Gyre and over Porcupine Bank. A less intense southerly flow from Porcupine Bank was observed both under climatological conditions and in the 1995 simulation, when winds were more variable than in 1994. The results based on the 1995 meteorological conditions showed the most extreme retention of tracers in the Rockall Trough/shelf-edge area west of Scotland and a low penetration of tracers onto the shelf. These results are discussed in relation to the observed distribution of 0-group juveniles and to indices of year-class strength - in particular, in relation to the 1995 year class, which is the highest year-class estimate of blue whiting on record. [ABSTRACT FROM AUTHOR]