Development of a prediction model for emergency medical service witnessed traumatic out-of-hospital cardiac arrest: A multicenter cohort study.

BACKGROUND/PURPOSE: To develop a prediction model for emergency medical technicians (EMTs) to identify trauma patients at high risk of deterioration to emergency medical service (EMS)-witnessed traumatic cardiac arrest (TCA) on the scene or en route. METHODS: We developed a prediction model using the classical cross-validation method from the Pan-Asia Trauma Outcomes Study (PATOS) database from 1 January 2015 to 31 December 2020. Eligible patients aged ≥18 years were transported to the hospital by the EMS. The primary outcome (EMS-witnessed TCA) was defined based on changes in vital signs measured on the scene or en route. We included variables that were immediately measurable as potential predictors when EMTs arrived. An integer point value system was built using multivariable logistic regression. The area under the receiver operating characteristic (AUROC) curve and Hosmer-Lemeshow (HL) test were used to examine discrimination and calibration in the derivation and validation cohorts. RESULTS: In total, 74,844 patients were eligible for database review. The model comprised five prehospital predictors: age <40 years, systolic blood pressure <100 mmHg, respiration rate >20/minute, pulse oximetry <94%, and levels of consciousness to pain or unresponsiveness. The AUROC in the derivation and validation cohorts was 0.767 and 0.782, respectively. The HL test revealed good calibration of the model (p = 0.906). CONCLUSION: We established a prediction model using variables from the PATOS database and measured them immediately after EMS personnel arrived to predict EMS-witnessed TCA. The model allows prehospital medical personnel to focus on high-risk patients and promptly administer optimal treatment.

Superfluid density in conventional superconductors: from clean to strongly disordered.

The highly convergent form of superfluid density in disordered conventional superconductors available in the literature and independently obtained by us following the approach of an earlier paper (Mandal and Ramakrishnan 2020Phys. Rev.B102024514) has been reformulated to separate out the generally used so-called 'dirty-limit' term and an additional term. We use this new expression for making an extensive comparison with previously published experimental data and show that the former, generally used, term isnotsufficient for analyzing these results. We point out that consequently, there is a large regime (disordered superconductors with moderate to no disorder) where theoretical predictions need to be confronted with experiment.

Indian Resuscitation Council (IRC) suggested guidelines for Comprehensive Cardiopulmonary Life Support (CCLS) for suspected or confirmed coronavirus disease (COVID-19) patient.

Management of the recent outbreak of the novel coronavirus disease (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) remains challenging. The challenges are not only limited to its preventive strategies, but also extend to curative treatment, and are amplified during the management of critically ill patients with COVID-19. Older persons with comorbidities like diabetes mellitus, cardiac diseases, hepatic impairment, renal disorders and respiratory pathologies or immune impairing conditions are more vulnerable and have a higher mortality from COVID-19. Earlier, the Indian Resuscitation Council (IRC) had proposed the Comprehensive Cardiopulmonary Life Support (CCLS) for management of cardiac arrest victims in the hospital setting. However, in patients with COVID-19, the guidelines need to be modified,due to various concerns like differing etiology of cardiac arrest, virulence of the virus, risk of its transmission to rescuers, and the need to avoid or minimize aerosolization from the patient due to various interventions. There is limited evidence in these patients, as the SARS-CoV-2 is a novel infection and not much literature is available with high-level evidence related to CPR in patients of COVID-19. These suggested guidelines are a continuum of CCLS guidelines by IRC with an emphasis on the various challenges and concerns being faced during the resuscitative management of COVID-19 patients with cardiopulmonary arrest.

Marginally Self-Averaging One-Dimensional Localization in Bilayer Graphene.

The combination of a field-tunable band gap, topological edge states, and valleys in the band structure makes insulating bilayer graphene a unique localized system, where the scaling laws of dimensionless conductance g remain largely unexplored. Here we show that the relative fluctuations in lng with the varying chemical potential, in strongly insulating bilayer graphene (BLG), decay nearly logarithmically for a channel length up to L/ξ≈20, where ξ is the localization length. This "marginal" self-averaging, and the corresponding dependence of ⟨lng⟩ on L, suggests that transport in strongly gapped BLG occurs along strictly one-dimensional channels, where ξ≈0.5±0.1 µm was found to be much longer than that expected from the bulk band gap. Our experiment reveals a nontrivial localization mechanism in gapped BLG, governed by transport along robust edge modes.

Computer-Based CPR Simulation Towards Validation of AHA/ERC Guidelines.

As per the AHA 2015 and ERC 2015 guidelines for resuscitation, chest compression depth should be between 5 and 6 cm with a rate of 100-120 compressions per minute. Theoretical validation of these guidelines is still elusive. We developed a computer model of the cardiopulmonary resuscitation (CPR) system to validate these guidelines. A lumped element computer model of the cardiovascular system was developed to simulate cardiac arrest and CPR. Cardiac output was compared for a range of compression pressures and frequencies. It was observed from our investigation that there is an optimum compression pressure and rate. The maximum cardiac output occurred at 100 mmHg, which is approximately 5.7 cm, and in the range of 100 to 120 compressions per minute with an optimum value at 110 compressions per minute, validating the guidelines. Increasing the pressure or the depth of compression beyond the optimum, limits the blood flow by depleting the volume in the cardiac chambers and not allowing for an effective stroke volume. Similarly increasing the compression rate beyond the optimum degrades the ability of the chambers to pump blood. The results also bring out the importance of complete recoil of the chest after each compression with more than 400% increase in cardiac output from 90% recoil to 100% recoil. Our simulation predicts that the recommendation to compress harder and faster is not the best counsel as there is an optimum compression pressure and rate for high-quality CPR.

Emergency medicine as a specialty in Asia.

Aim: We aim to examine the similarities and differences in areas of EM development, workload, workforce, and capabilities and support in the Asia region. Emerging challenges faced by our EM community are also discussed. Methods: The National Societies for Emergency Medicine of Hong Kong, India, Japan, Malaysia, Philippines, Singapore, South Korea, Taiwan, Thailand and Turkey participated in the joint Japanese Association of Acute Medicine (JAAM) and Asian Conference of Emergency Medicine (ACEM) Special Symposium held in October 2013 at Tokyo, Japan. The findings are reviewed in this paper. Results: Emergency medicine (EM) has over the years evolved into a distinct and recognized medical discipline requiring a unique set of cognitive, administrative and technical skills for managing all types of patients with acute illness or injury. EM has contributed to healthcare by providing effective, safe, efficient and cost-effective patient care. Integrated systems have developed to allow continuity of emergency care from the community into emergency departments. Structured training curriculum for undergraduates, and specialty training programs for postgraduates are in place to equip trainees with the knowledge and skills required for the unique practice of EM. Conclusion: The practice of EM still varies among the Asian countries. However, as a region, we strive to continue in our efforts to develop the specialty and improve the delivery of EM.

Stochastic kinetics of ribosomes: single motor properties and collective behavior.

Syntheses of protein molecules in a cell are carried out by ribosomes. A ribosome can be regarded as a molecular motor which utilizes the input chemical energy to move on a messenger RNA (mRNA) track that also serves as a template for the polymerization of the corresponding protein. The forward movement, however, is characterized by an alternating sequence of translocation and pause. Using a quantitative model, which captures the mechanochemical cycle of an individual ribosome, we derive an exact analytical expression for the distribution of its dwell times at the successive positions on the mRNA track. Inverse of the average dwell time satisfies a "Michaelis-Menten-type" equation and is consistent with the general formula for the average velocity of a molecular motor with an unbranched mechanochemical cycle. Extending this formula appropriately, we also derive the exact force-velocity relation for a ribosome. Often many ribosomes simultaneously move on the same mRNA track, while each synthesizes a copy of the same protein. We extend the model of a single ribosome by incorporating steric exclusion of different individuals on the same track. We draw the phase diagram of this model of ribosome traffic in three-dimensional spaces spanned by experimentally controllable parameters. We suggest new experimental tests of our theoretical predictions.

Fluctuations in protein synthesis from a single RNA template: stochastic kinetics of ribosomes.

Proteins are polymerized by cyclic machines called ribosomes, which use their messenger RNA (mRNA) track also as the corresponding template, and the process is called translation. We explore, in depth and detail, the stochastic nature of the translation. We compute various distributions associated with the translation process; one of them--namely, the dwell time distribution--has been measured in recent single-ribosome experiments. The form of the distribution, which fits best with our simulation data, is consistent with that extracted from the experimental data. For our computations, we use a model that captures both the mechanochemistry of each individual ribosome and their steric interactions. We also demonstrate the effects of the sequence inhomogeneities of real genes on the fluctuations and noise in translation. Finally, inspired by recent advances in the experimental techniques of manipulating single ribosomes, we make theoretical predictions on the force-velocity relation for individual ribosomes. In principle, all our predictions can be tested by carrying out in vitro experiments.

Coulomb interactions and nanoscale electronic inhomogeneities in manganites.

We study electronic inhomogeneities in manganites using simulations on a microscopic model with Coulomb interactions amongst two electronic fluids-one localized (polaronic), the other extended-and dopant ions. The long range Coulomb interactions frustrate phase separation induced by the large on site repulsion between the fluids. A single phase ensues which is inhomogeneous at a nanoscale, but homogeneous on mesoscales, with many features that agree with experiments. This, we argue, is the origin of nanoscale inhomogeneities in manganites, rather than phase competition or disorder effects.

Stochastic simulations of the origins and implications of long-tailed distributions in gene expression.

Gene expression noise results in protein number distributions ranging from long-tailed to Gaussian. We show how long-tailed distributions arise from a stochastic model of the constituent chemical reactions and suggest that, in conjunction with cooperative switches, they lead to more sensitive selection of a subpopulation of cells with high protein number than is possible with Gaussian distributions. Single-cell-tracking experiments are presented to validate some of the assumptions of the stochastic simulations. We also examine the effect of DNA looping on the shape of protein distributions. We further show that when switches are incorporated in the regulation of a gene via a feedback loop, the distributions can become bimodal. This might explain the bimodal distribution of certain morphogens during early embryogenesis.

Theory of insulator metal transition and colossal magnetoresistance in doped manganites.

The persistent proximity of insulating and metallic phases, a puzzling characteristic of manganites, is argued to arise from the self-organization of the twofold degenerate e(g) orbitals of Mn into localized Jahn-Teller (JT) polaronic levels and broad band states due to the large electron-JT phonon coupling present in them. We describe a new two band model with strong correlations and a dynamical mean-field theory calculation of equilibrium and transport properties. These explain the insulator metal transition and colossal magnetoresistance quantitatively, as well as other consequences of two state coexistence.

Tracking operator state fluctuations in gene expression in single cells.

We report the results of operator state fluctuations in gene expression for the entire bacterial growth cycle, using single-cell analysis and synthetic unregulated and negative-feedback transcription regulatory gene circuits. In the unregulated circuit, during the cell cycle, we observe a crossover from log-normal-to-normal distribution of expressed proteins and an unusual linear dependence of their standard deviation on the mean gene expression levels. With negative-feedback circuits we find the existence of bimodality as the cell cycle progresses. We suggest that such long-tail and bimodal distributions may be used as selection mechanisms in developmental switches and for assigning cell identity.

Atrial entrapment of flow directed pulmonary artery catheter-a technique for non-surgical removal.

A 43 year old patient who underwent mitral valve replacement had pulmonary artery catheter inserted before induction of anaesthesia. The catheter could no be removed postoperatively by routine manoeuvres in the intensive care unit. Fluoroscopy in the cardiac catheterization revealed a straight course of the catheter indicating the probability of its inclusion in the left atrial suture line. The pulmonary artery catheter was successfully removed percutaneously in the cardiac catheterization laborartory. The procedure is described.