A quantitative evaluation of aerosol generation during cardiopulmonary resuscitation.

It is unclear if cardiopulmonary resuscitation is an aerosol-generating procedure and whether this poses a risk of airborne disease transmission to healthcare workers and bystanders. Use of airborne transmission precautions during cardiopulmonary resuscitation may confer rescuer protection but risks patient harm due to delays in commencing treatment. To quantify the risk of respiratory aerosol generation during cardiopulmonary resuscitation in humans, we conducted an aerosol monitoring study during out-of-hospital cardiac arrests. Exhaled aerosol was recorded using an optical particle sizer spectrometer connected to the breathing system. Aerosol produced during resuscitation was compared with that produced by control participants under general anaesthesia ventilated with an equivalent respiratory pattern to cardiopulmonary resuscitation. A porcine cardiac arrest model was used to determine the independent contributions of ventilatory breaths, chest compressions and external cardiac defibrillation to aerosol generation. Time-series analysis of participants with cardiac arrest (n = 18) demonstrated a repeating waveform of respiratory aerosol that mapped to specific components of resuscitation. Very high peak aerosol concentrations were generated during ventilation of participants with cardiac arrest with median (IQR [range]) 17,926 (5546-59,209 [1523-242,648]) particles.l-1 , which were 24-fold greater than in control participants under general anaesthesia (744 (309-2106 [23-9099]) particles.l-1 , p < 0.001, n = 16). A substantial rise in aerosol also occurred with cardiac defibrillation and chest compressions. In a complimentary porcine model of cardiac arrest, aerosol recordings showed a strikingly similar profile to the human data. Time-averaged aerosol concentrations during ventilation were approximately 270-fold higher than before cardiac arrest (19,410 (2307-41,017 [104-136,025]) vs. 72 (41-136 [23-268]) particles.l-1 , p = 0.008). The porcine model also confirmed that both defibrillation and chest compressions generate high concentrations of aerosol independent of, but synergistic with, ventilation. In conclusion, multiple components of cardiopulmonary resuscitation generate high concentrations of respiratory aerosol. We recommend that airborne transmission precautions are warranted in the setting of high-risk pathogens, until the airway is secured with an airway device and breathing system with a filter.

A knowledge broker facilitated intervention to improve the use of standardized assessment tools by physical therapists: A cluster randomized trial.

OBJECTIVE: To compare two methods of knowledge broker support to improve standardized assessment use. DESIGN: Two-site cluster randomized trial. SETTING: Acute rehabilitation hospital. PARTICIPANTS: 18 physical therapists. INTERVENTION: A 10-month intervention was collaboratively designed with an external knowledge broker and physical therapists to compare full and partial implementation support. The knowledge broker provided education and strategies for implementation to the fully supported group and recommended strategies to the partially supported group that they self-implemented. MEASUREMENT: Chart audit data documenting frequency of use was extracted at four timepoints. Ten focus groups were conducted to describe factors that influenced use. Focus group data were coded using the Consolidated Framework for Implementation Research and rated as barriers and facilitators for standardized assessment use. RESULTS: For the fully supported group, standardized assessment use at initial examination increased from 0% to 58.3% at month 2 and decreased to 17.6% and 11.8% at months 4 and 8-10. For the partially supported group, standardized assessment use increased from 0% to 46% and 50% at month 2 and 4 and decreased to 2.8% at months 8-10. For both groups, early use was seen multiple facilitators. At month 10, barriers included organizational changes that impacted intervention fit. In addition, the fully supported group didn't value the selected standardized assessment and the partially supported group lacked space. CONCLUSIONS: Knowledge broker support improved both groups standardized assessment use early on, but it was not sustained. The amount of support could not be isolated as factors that influenced use varied by groups.

Classical dynamical coarse-grained entropy and comparison with the quantum version.

We develop the framework of classical observational entropy, which is a mathematically rigorous and precise framework for nonequilibrium thermodynamics, explicitly defined in terms of a set of observables. Observational entropy can be seen as a generalization of Boltzmann entropy to systems with indeterminate initial conditions, and it describes the knowledge achievable about the system by a macroscopic observer with limited measurement capabilities; it becomes Gibbs entropy in the limit of perfectly fine-grained measurements. This quantity, while previously mentioned in the literature, has been investigated in detail only in the quantum case. We describe this framework reasonably pedagogically, then show that in this framework, certain choices of coarse-graining lead to an entropy that is well-defined out of equilibrium, additive on independent systems, and that grows toward thermodynamic entropy as the system reaches equilibrium, even for systems that are genuinely isolated. Choosing certain macroscopic regions, this dynamical thermodynamic entropy measures how close these regions are to thermal equilibrium. We also show that in the given formalism, the correspondence between classical entropy (defined on classical phase space) and quantum entropy (defined on Hilbert space) becomes surprisingly direct and transparent, while manifesting differences stemming from noncommutativity of coarse-grainings and from nonexistence of a direct classical analog of quantum energy eigenstates.

Computational mechanisms in genetic regulation by RNA.

The evolution of the genome has led to very sophisticated and complex regulation. Because of the abundance of non-coding RNA (ncRNA) in the cell, different species will promiscuously associate with each other, suggesting collective dynamics similar to artificial neural networks. A simple mechanism is proposed allowing ncRNA to perform computations equivalent to neural network algorithms such as Boltzmann machines and the Hopfield model. The quantities analogous to the neural couplings are the equilibrium constants between different RNA species. The relatively rapid equilibration of RNA binding and unbinding is regulated by a slower process that degrades and creates new RNA. The model requires that the creation rate for each species be an increasing function of the ratio of total to unbound RNA. Similar mechanisms have already been found to exist experimentally for ncRNA regulation. With the overall concentration of RNA regulated, equilibrium constants can be chosen to store many different patterns, or many different input-output relations. The network is also quite insensitive to random mutations in equilibrium constants. Therefore one expects that this kind of mechanism will have a much higher mutation rate than ones typically regarded as being under evolutionary constraint.

Altered brain activation in complex walking conditions in patients with Parkinson's disease.

INTRODUCTION: Behavioral studies suggest that deficits in cognitive domains and sensory-motor processes associated with Parkinson's disease (PD) impair the ability to walk in complex environments. However, the neural correlates of locomotion in complex environments are still unclear. METHODS: Twenty healthy older adults (mean age 69.7 ± 1.3 yrs) and 20 patients with PD (mean age 72.9 ± 1.6 yrs; disease duration: 6.8 ± 1.3 yrs; UPDRSIII: 29.8 ± 2.4) were asked to imagine themselves walking while in the MRI scanner. Three imagined walking tasks, i.e., usual walking, obstacle negotiation, and navigation were performed. Watching the same virtual scenes without imagining walking served as control tasks. Whole brain analyses were used. RESULTS: Compared to usual walking, both groups had increased activation during obstacle negotiation in middle occipital gyrus (MOG) (pFWEcorr<0.001), middle frontal gyrus (MFG) (pFWEcorr<0.005), and cerebellum (pFWEcorr<0.001). Healthy older adults had higher activation in precuneus and MOG (pFWEcorr<0.023) during navigation, while no differences were observed in patients with PD. Between group comparisons revealed that patients with PD had a significantly higher activation in usual walking and obstacle negotiation (pFWEcorr<0.039) while during navigation task, healthy older adults had higher activation (pFWEcorr<0.047). CONCLUSIONS: Patients with PD require greater activation during imagined usual walking and obstacle negotiation than healthy older adults. This increased activation may reflect a compensatory attempt to overcome inefficient neural activation in patients with PD. This increased activation may reduce the functional reserve needed during more demanding tasks such as during navigation which may contribute to the high prevalence of falls and dual tasking difficulties among patients with PD.

Virtual reality for stroke rehabilitation: an abridged version of a Cochrane review.

Virtual reality and interactive video gaming have emerged as new treatment approaches in stroke rehabilitation settings over the last ten years. The primary objective of this review was to determine the effectiveness of virtual reality on upper limb function and activity after stroke. The impact on secondary outcomes including gait, cognitive function and activities of daily living was also assessed. Randomized and quasi-randomized controlled trials comparing virtual reality with an alternative intervention or no intervention were eligible to be included in the review. The authors searched a number of electronic databases including: the Cochrane Stroke Group Trials Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, AMED, CINAHL, PsycINFO, clinical trial registers, reference lists, Dissertation Abstracts and contacted key researchers in the field. Search results were independently examined by two review authors to identify studies meeting the inclusion criteria. A total of 37 randomized or quasi randomized controlled trials with a total of 1019 participants were included in the review. Virtual reality was found to be significantly more effective than conventional therapy in improving upper limb function (standardized mean difference [SMD] 0.28, 95% confidence intervals [CI] 0.08 to 0.49) based on 12 studies and significantly more effective than no therapy in improving upper limber function (SMD 0.44 [95% CI 0.15 to 0.73]) based on nine studies. The use of virtual reality also significantly improved activities of daily living function when compared to more conventional therapy approaches (SMD 0.43 [95% CI 0.18 to 0.69]) based on eight studies. While there are a large number of studies assessing the efficacy of virtual reality they tend to be small and many are at risk of bias. While there is evidence to support the use of virtual reality intervention as part of upper limb training programs, more research is required to determine whether it is beneficial in terms of improving lower limb function and gait and cognitive function.

Institutional food as a lever for improving health in cities: the case of New York City.

OBJECTIVES: To describe and examine the factors that most facilitate and impede the provision of healthy foods in a complex institutional food system. STUDY DESIGN: Comparative case study of three institutional food settings in New York City. METHODS: Document review and interviews with relevant city government staff. RESULTS: Factors that facilitate and impede the provision of healthy food vary across institutional food settings, and particularly between centralized and decentralized settings. Generally pro-health factors include centralized purchasing and the ability to work with vendors to formulate items to improve nutritional quality, though decentralized purchasing may offer more flexibility to work with vendors offering healthier food items and to respond to consumer preferences. Factors most often working against health in more centralized systems include financing constraints that are unique to particular settings. In less centralized systems, factors working against health may include both financing constraints and factors that are site-specific, relating to preparation and equipment. CONCLUSIONS: Making changes to institutional food systems that will meaningfully influence public health requires a detailed understanding of the diverse systems supporting and shaping public food provision. Ultimately, the cases in this study demonstrate that agency staff typically would like to provide healthier foods, but often feel limited by the competing objectives of affordability and consumer preference. Their ability to address these competing objectives is shaped by a combination of both forces external to the institution, like nutritional regulations, and internal forces, like an agency's structure, and motivation on the part of staff.

Motor function in interpolar microtubules during metaphase.

We analyze experimental motility assays of microtubules undergoing small fluctuations about a "balance point" when mixed in solution of two different kinesin motor proteins, KLP61F and Ncd. It has been proposed that the microtubule movement is due to stochastic variations in the densities of the two species of motor proteins. We test this hypothesis here by showing how it maps onto a one-dimensional random walk in a random environment. Our estimate of the amplitude of the fluctuations agrees with experimental observations. We point out that there is an initial transient in the position of the microtubule where it will typically move of order its own length. We compare the physics of this gliding assay to a recent theory of the role of antagonistic motors on restricting interpolar microtubule sliding of a cell's mitotic spindle during prometaphase. It is concluded that randomly positioned antagonistic motors can restrict relative movement of microtubules, however they do so imperfectly. A variation in motor concentrations is also analyzed and shown to lead to greater control of spindle length.

[Early childhood intervention - access to risk families and support through actors from the health-care sector]. / Frühe Hilfe für Familien und Frühgeborene - Zugangswege und Unterstützungen aus dem Gesundheitsbereich.

Interdisciplinary cooperation and networking determine the success of activities for supporting families at risk for early childhood abuse. The integration of the healthcare sector might be important.The medical standard of perinatal care at the University hospital includes information exchange about family risk factors which may contribute to an increased risk of child abuse within the first year of life. As a result, the -pediatrician offered supporting services for the families at the time of the second examination during the official childhood health screening program (U2). A team of family-sponsorship was established and evaluated.In 281 of 1238 risk-factor questionnaires at least one stress factor was detected and 97 families had high-impact family stress. Families under the supervision of a family midwife or youth services had a significantly higher number of risk factors. The family-sponsorship program was institutionalized and positively evaluated by the families.The time of a hospital delivery is an excellent opportunity for the evaluation of familial risk factors and for the provision of supporting services. To increase the acceptance of such services by the families at risk repeated assessment of risk factors and support offers are required.

Feasibility, safety and outcomes of playing Kinect Adventures!™ for people with Parkinson's disease: a pilot study.

OBJECTIVES: To assess the feasibility, safety and outcomes of playing Microsoft Kinect Adventures™ for people with Parkinson's disease in order to guide the design of a randomised clinical trial. DESIGN: Single-group, blinded trial. SETTING: Rehabilitation Center of São Camilo University, Brazil. PARTICIPANTS: Seven patients (six males, one female) with Parkinson's disease (Hoehn and Yahr Stages 2 and 3). INTERVENTIONS: Fourteen 60-minute sessions, three times per week, playing four games of Kinect Adventures! MAIN OUTCOME MEASURES: The feasibility and safety outcomes were patients' game performance and adverse events, respectively. The clinical outcomes were the 6-minute walk test, Balance Evaluation System Test, Dynamic Gait Index and Parkinson's Disease Questionnaire (PDQ-39). RESULTS: Patients' scores for the four games showed improvement. The mean [standard deviation (SD)] scores in the first and last sessions of the Space Pop game were 151 (36) and 198 (29), respectively [mean (SD) difference 47 (7), 95% confidence interval 15 to 79]. There were no adverse events. Improvements were also seen in the 6-minute walk test, Balance Evaluation System Test, Dynamic Gait Index and PDQ-39 following training. CONCLUSION: Kinect-based training was safe and feasible for people with Parkinson's disease (Hoehn and Yahr Stages 2 and 3). Patients improved their scores for all four games. No serious adverse events occurred during training with Kinect Adventures!, which promoted improvement in activities (balance and gait), body functions (cardiopulmonary aptitude) and participation (quality of life).

Conserving large populations of lions - the argument for fences has holes.

Packer et al. reported that fenced lion populations attain densities closer to carrying capacity than unfenced populations. However, fenced populations are often maintained above carrying capacity, and most are small. Many more lions are conserved per dollar invested in unfenced ecosystems, which avoid the ecological and economic costs of fencing.

Microscopic origin of thermodynamic entropy in isolated systems.

The quantum entropy is usually defined using von Neumann's formula, which measures lack of information and vanishes for pure states. In contrast, we obtain a formula for the entropy of a pure state as it is measured from thermodynamic experiments, solely from the self-entanglement of the wave function, and find strong numerical evidence that the two are in agreement for nonintegrable systems, both for energy eigenstates and for states that are obtained at long times under the evolution of more general initial conditions. This is an extension of Boltzmann's hypothesis for classical systems, relating microscopic motion to thermodynamics.

Measurement of muon capture on the proton to 1% precision and determination of the pseudoscalar coupling gP.

The MuCap experiment at the Paul Scherrer Institute has measured the rate Λ(S) of muon capture from the singlet state of the muonic hydrogen atom to a precision of 1%. A muon beam was stopped in a time projection chamber filled with 10-bar, ultrapure hydrogen gas. Cylindrical wire chambers and a segmented scintillator barrel detected electrons from muon decay. Λ(S) is determined from the difference between the µ(-) disappearance rate in hydrogen and the free muon decay rate. The result is based on the analysis of 1.2 × 10(10) µ(-) decays, from which we extract the capture rate Λ(S) = (714.9 ± 5.4(stat) ± 5.1(syst)) s(-1) and derive the proton's pseudoscalar coupling g(P)(q(0)(2) = -0.88 m(µ)(2)) = 8.06 ± 0.55.

Cochrane review: virtual reality for stroke rehabilitation.

AIM: Virtual reality and interactive video gaming are innovative therapy approaches in the field of stroke rehabilitation. The primary objective of this review was to determine the effectiveness of virtual reality on motor function after stroke. The impact on secondary outcomes including activities of daily living was also assessed. METHODS: Randomised and quasi-randomised controlled trials that compared virtual reality with an alternative or no intervention were included in the review. The authors searched the Cochrane Stroke Group Trials Register, the Cochrane Central Register of Controlled Trials, electronic databases, trial registers, reference lists, Dissertation Abstracts, conference proceedings and contacted key researchers and virtual reality manufacturers. Search results were independently examined by two review authors to identify studies meeting the inclusion criteria. RESULTS: Nineteen studies with a total of 565 participants were included in the review. Variation in intervention approaches and outcome data collected limited the extent to which studies could be compared. Virtual reality was found to be significantly more effective than conventional therapy in improving upper limb function (standardised mean difference, SMD) 0.53, 95% confidence intervals [CI] 0.25 to 0.81)) based on seven studies, and activities of daily living (ADL) function (SMD 0.81, 95% CI 0.39 to 1.22) based on three studies. No statistically significant effects were found for grip strength (based on two studies) or gait speed (based on three studies). CONCLUSION: Virtual reality appears to be a promising approach however, further studies are required to confirm these findings.

Ideal linear-chain polymers with fixed angular momentum.

The statistical mechanics of a linear noninteracting polymer chain with a large number of monomers is considered with fixed angular momentum. The radius of gyration for a linear polymer is derived exactly by functional integration. This result is then compared to simulations done with a large number of noninteracting rigid links at fixed angular momentum. The simulation agrees with the theory up to finite-size corrections. The simulations are also used to investigate the anisotropic nature of a spinning polymer. We find universal scaling of the polymer size along the direction of the angular momentum, as a function of rescaled angular momentum.

Collision of polymers in a vacuum.

In a number of experimental situations, single-polymer molecules can be suspended in a vacuum. Here collisions between such molecules are considered. The limit of high collision velocity is investigated numerically for a variety of conditions. The distribution of contact times, scattering angles, and final velocities are analyzed. In this limit, self-avoiding chains are found to become highly stretched as they collide with each other and have a distribution of scattering times that depends on the scattering angle. The velocity of the molecules after the collisions is similar to predictions of a model assuming thermal equilibration of molecules during the collision. The most important difference is a significant subset of molecules that inelastically scatter but do not substantially change direction.

Density fluctuations of polymers in disordered media.

We study self-avoiding random walks in an environment where sites are excluded randomly, in two and three dimensions. For a single polymer chain, we study the statistics of the time averaged monomer density and show that these are well described by multifractal statistics. This is true even far from the percolation transition of the disordered medium. We investigate solutions of chains in a disordered environment and show that the statistics cease to be multifractal beyond the screening length of the solution.

Internal dissipation of a polymer.

The dynamics of flexible polymer molecules are often assumed to be governed by hydrodynamics of the solvent. However there is considerable evidence that internal dissipation of a polymer contributes as well. Here we investigate the dynamics of a single chain in the absence of solvent to characterize the nature of this internal friction. We model the chains as freely hinged but with localized bond angles and threefold symmetric dihedral angles. We show that the damping is close but not identical to Kelvin damping, which depends on the first temporal and second spatial derivative of monomer position. With no internal potential between monomers, the magnitude of the damping is small for long wavelengths and weakly damped oscillatory time dependent behavior is seen for a large range of spatial modes. When the size of the internal potential is increased, such oscillations persist, but the damping becomes larger. However underdamped motion is present even with quite strong dihedral barriers for long enough wavelengths.