The LACE index and risk factors of 14-day versus 30-day readmissions in children.

Risk factors for readmissions in children differ from those in adults, yet little is known about whether the LACE index (Length of stay, Acute admission, Charlson comorbidity index, Emergency department visits in the previous 6 months) developed for adults retains its validity when applied to the prediction of readmissions in children or within shorter intervals of time after discharge. In this retrospective cohort analysis of 4256 patients aged ≤18 years hospitalized at one academic medical center in Taiwan in 2019, we first evaluated the performance of a LACE index model and the three other multivariate logistic regression models in their predictions of hospital readmissions in children using the same time interval of 30 days. We then used multinomial logistic regression to analyze the characteristics and risk factors for readmissions that occur in the first 14 days with those that occur between 15 and 30 days after discharge.

Early prediction of 30- and 14-day all-cause unplanned readmissions.

Background: An unplanned readmission is a dual metric for both the cost and quality of medical care.

Methods: We employed the random forest (RF) method to build a prediction model using a large dataset from patients' electronic health records (EHRs) from a medical center in Taiwan. The discrimination abilities between the RF and regression-based models were compared using the areas under the ROC curves (AUROC).

Influencing factors in the simulation of airflow and particle transportation in aircraft cabins by CFD.

To control the transport of particles such as the SARS-CoV-2 virus in airliner cabins, which is a significant concern for the flying public, effective ventilation systems are essential. Validated computational fluid dynamics (CFD) models are frequently and effectively used to investigate air distribution and contaminant transportation. The complex geometry and airflow characteristics in airliner cabins pose a challenge to numerical CFD validation.

Corrigendum to "Evaluation of different air distribution systems in a commercial airliner cabin in terms of comfort and COVID-19 infection risk" Build. Environ., Volume 208, January 2022, 108590.

[This corrects the article DOI: 10.1016/j.buildenv.

Evaluation of different air distribution systems in a commercial airliner cabin in terms of comfort and COVID-19 infection risk.

The air distribution system in an airliner plays a key role in maintaining a comfortable and healthy environment in the aircraft cabin. To evaluate the performance of a novel displacement ventilation (DV) system and a traditional mixing ventilation (MV) system in an airliner cabin, this study conducted experiments and simulations in a seven-row cabin mockup. This investigation used ultrasonic anemometers and T-thermocouples to measure the air velocity, temperature and distribution of 1 μm and 5 μm particles.

Experimental evaluation of particle exposure at different seats in a single-aisle aircraft cabin.

During the COVID-19 pandemic, exposure to particles exhaled by infected passengers in commercial aircraft cabins has been a great concern. Currently, aircraft cabins adopt mixing ventilation. However, complete mixing may not be achieved, and thus the particle concentration in the respiratory zone may vary from seat to seat in a cabin.

Evaluating the commercial airliner cabin environment with different air distribution systems.

Ventilation systems for commercial airliner cabins are important in reducing contaminant transport and maintaining thermal comfort. To evaluate the performance of a personalized displacement ventilation system, a conventional displacement ventilation system, and a mixing ventilation system, this study first used the Wells-Riley equation integrated with CFD to obtain the SARS quanta value based on a specific SARS outbreak on a flight. This investigation then compared the three ventilation systems in a seven-row section of a fully occupied, economy-class cabin in Boeing 737 and Boeing 767 airplanes.

Prediction of particle deposition around the cabin air supply nozzles of commercial airplanes using measured in-cabin particle emission rates.

Enhanced soiling on the surfaces around air supply nozzles due to particle deposition is frequently observed in commercial airliners. The problem is worsened by severe outdoor air pollution and flight delays in China. The particles in an aircraft cabin originate from both outdoor and in-cabin sources.

An innovative personalized displacement ventilation system for airliner cabins.

In airliner cabins, mixing ventilation systems with gaspers are not efficient in controlling contaminant transport. To improve the cabin environment, this investigation proposed an innovative ventilation system that would reduce contaminant transport and maintain thermal comfort. We manufactured and installed the proposed ventilation system in an occupied seven-row, single-aisle aircraft cabin mockup.

Logistic growth of a surface contamination network and its role in disease spread.

Surfaces and objects surround us, and touching them is integral to everyday life. Pathogen contaminated surfaces (fomites) are known to transmit diseases. However, little is known about the ways and speed at which surfaces become contaminated.

Design and characterization of a cough simulator.

Expiratory droplets from human coughing have always been considered as potential carriers of pathogens, responsible for respiratory infectious disease transmission. To study the transmission of disease by human coughing, a transient repeatable cough simulator has been designed and built. Cough droplets are generated by different mechanisms, such as the breaking of mucus, condensation and high-speed atomization from different depths of the respiratory tract.

Investigating the impact of gaspers on cabin air quality in commercial airliners with a hybrid turbulence model.

It is not clear whether turning on the gaspers in the cabins of commercial airliners actually improves the air quality. To answer this question, this study first developed a hybrid turbulence model which was suitable for predicting the air distribution in an aircraft cabin with gaspers turned on. Next, the investigation validated the model using two sets of experimental data from a cabin mockup and an actual airplane.

A Markov chain model for predicting transient particle transport in enclosed environments.

Obtaining information about particle dispersion in a room is crucial in reducing the risk of infectious disease transmission among occupants. This study developed a Markov chain model for quickly obtaining the information on the basis of a steady-state flow field calculated by computational fluid dynamics. When solving the particle transport equations, the Markov chain model does not require iterations in each time step, and thus it can significantly reduce the computing cost.

Experimental study of gaseous and particulate contaminants distribution in an aircraft cabin.

The environment of the aircraft cabin greatly influences the comfort and health of passengers and crew members. Contaminant transport has a strong effect on disease spreading in the cabin environment. To obtain the complex cabin contaminant distribution fields accurately and completely, which is also essential to provide solid and precise data for computational fluid dynamics (CFD) model validation, this paper aimed to investigate and improve the method for simultaneous particle and gaseous contaminant fields measurement.

A hybrid model for investigating transient particle transport in enclosed environments.

It is important to accurately model person-to-person particle transport in mechanical ventilation spaces to create and maintain a healthy indoor environment. The present study introduces a hybrid DES-Lagrangian and RANS-Eulerian model for simulating transient particle transport in enclosed environments; this hybrid model can ensure the accuracy and reduce the computing cost. Our study estimated two key time constants for the model that are important parameters for reducing the computing costs.

Constructing "behavioral" comparison groups: A difference-in-difference analysis of the effect of copayment based on the patient's price elasticity.

It is well known that the differences-in-differences (DD) estimator is based on the assumption that in the absence of treatment, the average outcomes for the treated group and the control group will follow a common trend over time. That can be problematic, especially when the selection for the treatment is influenced by the individual's unobserved behavior correlating with the medical utilization. The aim of this study was to develop an index for controlling a patient's unobserved heterogeneous response to reform, in order to improve the comparability of treatment assignment.

Risk assessment of airborne infectious diseases in aircraft cabins.

Unlabelled: Passengers in an aircraft cabin can have different risks of infection from airborne infectious diseases such as influenza, severe acute respiratory syndrome (SARS), and tuberculosis (TB) because of the non-uniform airflow in an aircraft cabin. The current investigation presents a comprehensive approach to assessing the spatial and temporal distributions of airborne infection risk in an aircraft cabin. A case of influenza outbreak was evaluated in a 4-h flight in a twin-aisle, fully occupied aircraft cabin with the index passenger seated at the center of the cabin.

State-of-the-art methods for studying air distributions in commercial airliner cabins.

Air distributions in commercial airliner cabins are crucial for creating a thermally comfortable and healthy cabin environment. This paper reviews the methods used in predicting, designing, and analyzing air distributions in the cabins, among which experimental measurements and numerical simulations are the two popular ones. The experimental measurements have usually been seen as more reliable although they are more expensive and time consuming.

Transport of expiratory droplets in an aircraft cabin.

Unlabelled: The droplets exhaled by an index patient with infectious disease such as influenza or tuberculosis may be the carriers of contagious agents. Indoor environments such as the airliner cabins may be susceptible to infection from such airborne contagious agents. The present investigation computed the transport of the droplets exhaled by the index patient seated in the middle of a seven-row, twin-aisle, fully occupied cabin using the CFD simulations.

Characterizing exhaled airflow from breathing and talking.

Unlabelled: The exhaled air of infected humans is one of the prime sources of contagious viruses. The exhaled air comes from respiratory events such as the coughing, sneezing, breathing and talking. Accurate information on the thermo-fluid characteristics of the exhaled airflow can be important for prediction of infectious disease transmission.