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.

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.

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.

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.

[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.

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.

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.

[Giant scalp mass]. / Monströser Tumor der Kopfhaut.

A 55-year-old man was referred to our department with bleeding from a painless tumor located at the left parietal region of the head which had been progressively growing for a period of 2 years. Physical examination showed a fist-sized pediculated mass overlying the left parietal region and the auricle. The partly livid and ulcerated surface of the tumor was interspersed with light-yellow chalky material. The mass was totally excised. Infiltration of the skull was not observed. Histopathological examination led to the diagnosis of a giant pilomatricoma. Pilomatricoma is a rare, benign skin neoplasm that originates from hair matrix cells and is most frequently located in the head and neck region.

[Prophylaxis of venous thromboembolism and anticoagulation bridging. Strategies in otorhinolaryngology]. / Thromboembolieprophylaxe und überbrückende Antikoagulation. Strategien in der HNO-Heilkunde.

Various interdisciplinary guidelines recommend that in-patients at risk of venous thromboembolism should receive pharmacologic prophylaxis. Among the anticoagulants low-molecular-weight heparins (LMWH) and fondaparinux can be considered the medications of choice because of the favorable pharmacokinetic properties when compared with unfractionated heparin. Treatment with vitamin K antagonists has to be interrupted in patients undergoing major surgery or invasive procedures. Oral anticoagulation has to be temporarily replaced by short-acting anticoagulants such as LMWH in order to prevent thromboembolic complications (anticoagulation bridging). Although LMWHs have not been approved for this clinical setting their efficacy and safety has been demonstrated in several recent studies. Detailed recommendations for prophylaxis of venous thromboembolism in otorhinolaryngology are lacking although numerous surgical procedures are considered to be associated with a significant risk of thromboembolism. A strategy for pharmacologic prophylaxis of venous thromboembolism and anticoagulation bridging in otorhinolaryngology is proposed.

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.

Theoretical studies of DNA during gel electrophoresis.

A numerical study of the motion of a long-chain macromolecule in a gel has shown unexpected features. The application of a field appears to induce the chain to contract on itself. This is followed by its "unwinding" into an extended configuration. For long chains, the mobility tends toward a constant, in accord with experiments. For the parameter range used, the observed molecular motion differs strongly from assumptions made in the present theory of electrophoresis.

The cholinergic synapse and the site of memory.

A simple hypothesis can explain the results obtained to date if we disregard those results when we wait 30 minutes after original learning to inject. The hypothesis is that, as a result of learning, the postsynaptic endings at a specific set of synapses become more sensitive to transmitter. This sensitivity increases with time after initial learning and then declines. The rate at which such sensitivity increases depends on the amount of initial learning. If the curve of transmission plotted against time is displaced upward with anticholinesterases then the very low portions will show facilitation, and the high portions will cause block (Fig. 8). The middle portions will appear unaffected (unless special experimental tests are made). If the curve of transmission is displaced down with anticholinergics, then the middle portion will appear unaffected and only the very early or late components will show block. The results are evidence that synaptic conductance is altered as a result of learning. So far it seems (i) that cholinergic synapses are modified as a result of learning and that it probably is the postsynaptic membrane that becomes increasingly more sensitive to acetylcholine with time after learning, up to a certain point. (ii) After this point, sensitivity declines, leading to the phenomenon of forgetting. (iii) There is also good evidence that there is an initial phase of declining sensitivity to cholinesterase or increasing sensitivity to anticholinergics. This could reflect the existence of a parallel set of synapses with fast decay that serve as a shortterm store. (iv) Increasing the amount of learning leads to an increase in conductance in each of a set of synapses without an increase in their number. (v) Both original learning and extinction are subserved by cholinergic synapses.

Anticholinesterase-induced amnesia and its temporal aspects.

Injection of the anticholinesterase drug diisopropyl fluorophosphate into the hippocampi of rats, 30 minutes after escape learning, produces partial amnesia with full recovery 5 days after injection. No such amnesia is produced if the injection takes place 3 days after learning. However, with injections 5 days after learning there is again an effect, and at 14 days amnesia is complete though no normal forgetting occurs within this period.

Amnesia or reversal of forgetting by anticholinesterase, depending simply on time of injection.

The effect of intracerebral injections of the anticholinesterase drug diisopropyl fluorophosphate in rats was to produce good recall of an otherwise almost forgotten habit learned 28 days before. The same injections produced temporary amnesia for the same habit, otherwise well remembered, learned 14 days before. The injections had no ef fect on the memory of the same habit when it was only partly learned 14 days before. The results support the hy pothesis that the physiological basis of memory lies in an increase, and for getting in a decrease, in synaptic con ductance.

Preference enhancement for alcohol by passive exposure.

A large and lasting enhancement of alcohol consumption over control levels is reported after direct infusion of 10 percent alcohol into the stomach of rats for 6 days.

The stomach as a site for rapid nutrient reinforcement sensors.

Rats with inflated cuffs placed around the pyloric sphincter were given a choice between two nonnutritive solutions. Ingestion of one solution was paired with nutritive intragastric injections and ingestion of the other was paired with saline injections. The preference of rats for the nutrient-paired flavors indicates that the stomach alone can rapidly detect the arrival of nutritive substances.

Diazepam maintenance of alcohol preference during alcohol withdrawal.

After forced intragastric intubation of alcohol, rats will show a greatly increased tendency to self-administer alcohol in a free-choice situation. Diazepam (Valium) dosage (5 milligrams per kilogram of body weight) during the period ow withdrawal serves to maintain undiminished such alcohol self-administration. Without such diazepam dosage the tendency to self-administer alcohol returns to control levels.

The stomach signals satiety.

Inflatable pyloric cuffs and stomach tubes were implanted in rats. With the cuff inflated and a valve to limit intragastric pressure to that accompanying normal satiety, they drank only as much when they had been deprived of food for 12 hours as without inflation of the cuff. However, they overdrank with the cuff inflated when they had been water deprived for 12 hours. When 10 ml of milk was withdrawn from the stomach with the cuff inflated, compensatory drinking occurred. Further, compensatory drinking also occurred when milk escaped from the stomach into the duodenum. Satiety signals thus arise from the stomach.

Behavioral measurement of neural poststimulation excitability cycle: pain cells in the brain of the rat.

A new technique in which elicited behavior of the freely moving rat is used to measure the poststimulation excitability cycle of the central neurons mediating that behavior has been adapted from accepted methods of neurophysiology. A continuous train of pairs of brief pulses was delivered to pain systems in the midbrain. Rate of lever pressing to achieve 3-second rests from this stimulation was measured as a function of the interval separating the pulses within pairs. Evidence for latent addition, absolute refractory period, temporal summation, and adaptation was demonstrated. Obtained relationships suggested that three sets of fibers may carry the aversive signal and that synaptic integration of pain in the brain may be related to Stevens' power law functions.