CD4+ T cells related to disease severity in elderly and frailty community-acquired pneumonia patients: A retrospective cohort study.

BACKGROUNDS: Elderly and frailty individuals show a more senescent immune system, which may relate to worse outcome in community-acquired pneumonia (CAP). This study aimed to explore prognostic factors related to immune. METHODS: Sixty of elderly (≥65 years) and frailty (clinical frailty scale ≥5 scores) nonsevere CAP patients and 60 severe CAP (SCAP) patients were recruited at our center. Clinical and laboratory data, and several assessment scores were collected. RESULTS: Compared with nonsevere CAP group, the elderly and frailty SCAP patients showed higher level of BMI, PaCO2 and lactate in arterial blood-gas, CURB-65 score, ICU admission, mechanical ventilation, shock accidence, and longer hospital stay using two-tailed t test. The SCAP group also showed increased CRP, IL-6, and PCT, and decreased CD3+ T cells, CD4+ T cells, and CD8+ T cells. Logistic regression analysis showed that CD4+ T cells, IL-6 and PCT were independent prognostic factors for SCAP. The area under the receiver operating characteristic (ROC) curve for CD4+ T cells combined with PCT was 0.771 (95% CI 0.683-0.859), and the sensitivity and specificity were both 76.7%. Paired t test analysis showed that low CD4+ T cells in SCAP patients increased after treatment. CONCLUSIONS: CD4+ T cells decreased in elderly and frailty SCAP patients, and CD4+ T cells combined with PCT were relatively accurate in the prediction of elderly and frailty SCAP.

Analytical Model for Heat Transfer in a Discrete Parallel Fracture-Rock Matrix System.

Mass transport and heat transfer in the single fracture situated in the rock matrix have been investigated extensively in the past decades. Extended from the single fracture, the model of parallel fractures in the rock matrix considers the interactions of multiple fractures and the ambient rock matrix. Heat transfer in such discrete fractures is important to understand thermal energy transfer in the fractured porous media. In this study, an analytical solution is developed for transient heat transfer in discrete parallel fractures in the rock matrix. The newly proposed model accounts for thermal convection, conduction, and dispersion in the fractures, transverse thermal conduction in the rock matrix, and the interactions between parallel fractures. The analytical solutions of the spatiotemporal temperature distributions in the fractures and rock matrix are derived in the Laplace domain and verified with the previous study. The results illustrate that: (1) the fracture aperture and spacing are important to the temperature evolutions in the system. Heat transfers faster when discrete parallel fractures are wide and closely spaced; (2) different roles of longitudinal thermal conduction are observed at high and low flow velocities in the fractures; (3) thermal dispersivity in the fractures is important for temperature evolution and should not be ignored; (4) when the fractures are closely spaced, transverse thermal conduction in the rock matrix has minor influence on fracture temperature. It becomes important when the fractures are sparsely distributed; and (5) the sensitivity analysis indicates that the parallel fracture-rock matrix is most sensitive to fracture thermal dispersivity.

A novel analytical model of solute transport in a layered aquifer system with mixing processes in the reservoirs.

Analytical models of solute transport have been widely used to aid the understanding of the physical and chemical processes undergone by substances introduced in a layered aquifer system. However, in previous studies, the advection component of transport was assumed to be one dimensional, while also ignoring the mixing processes that occur in the inlet and the outlet reservoirs. In this study, new sets of models describing those mixing processes are presented. Beyond that, these models were integrated into already existing models and the result is a novel analytical model of solute transport in aquifer-aquitard systems. The novel analytical solution was derived by the Laplace transform method and the finite-cosine Fourier transform method under the mobile-immobile (MIM) framework. The calculations take into account: the longitudinal and vertical dispersion, the molecular diffusion and the horizonal and vertical advection components of solute transport, as well as first-order chemical reaction, in both the aquifer and the aquitard. A finite-difference solution of the model is tested against experimental data in order to critique its reliability. Results indicate that the numerical and analytical solutions of the new model match well with experimental data. This new model outperforms the previous models in terms of interpreting experimental data. The mixing old and new water in the reservoirs during solute transport in aquifer-aquitard systems is important. Global sensitivity analysis demonstrates that the output concentration of solute in the aquifer-aquitard system is most sensitive to the volume of water in the inlet reservoir. The contribution of the molecular diffusion effect to the total mass flux of the tracer cross the aquifer-aquitard interface is much smaller than the contribution of the dispersive and advective effects.

Assessment of the impact of geogenic and climatic factors on global risk of urinary stone disease.

Urinary Stone Disease (USD) or urolithiasis has plagued humans for centuries, and its prevalence has increased over the past few decades. Although USD pathology could vary significantly among individuals, previous qualitative assessments using limited survey data demonstrated that the prevalence of USD might exhibit a distinctive geographical distribution (the so-called "stone belt"), without any knowledge about the characteristics and contribution factors of the belt. Here, we argue that the spatial distribution of USD can at least partly be explained by geogenic and climatic factors, as it correlates with the ambient geo-environmental conditions modulated by lithology/mineralogy, water quality and climate. Using a Bayesian risk model, we assessed the global risk of USD based on updated big data of four key geogenic factors: phosphorite mines (inventory >1600 points), carbonate rocks (at the scale of 1:40 million), Ca2+/Mg2+ molar ratio of river water (1.27 million samples distributed over 17,000 sampling locations), and mean air temperature (0.5o × 0.5° resolution) representing the climate. We quantitatively identified possible contributions of the factors to USD and delineated the regions with the high USD risk which stretched from southern North America, via the Mediterranean region, northeastern Africa, southern China to Australia, and roughly coincide with the world's major areas of carbonate outcropping. Under current climate conditions, the areas with the probabilities for the USD prevalence of ≥50% and ≥30% covered 3.7% and 20% of the Earth's land surface, respectively. By the end of the 21st century, such total areas could rise to 4.4% and 25% as a result of global warming. Since the USD data used in this study were quite heterogeneous, the prediction results needed further calibration with additional high-quality prevalence data in the future.

A new package in MODFLOW to simulate unconfined groundwater flow in sloping aquifers.

The nonhorizontal-model-layer (NHML) grid system is more accurate than the horizontal-model-layer grid system to describe groundwater flow in an unconfined sloping aquifer on the basis of MODFLOW-2000. However, the finite-difference scheme of NHML was based on the Dupuit-Forchheimer assumption that the streamlines were horizontal, which was acceptable for slope less than 0.10. In this study, we presented a new finite-difference scheme of NHML based on the Boussinesq assumption and developed a new package SLOPE which was incorporated into MODFLOW-2000 to become the MODFLOW-SP model. The accuracy of MODFLOW-SP was tested against solution of Mac Cormack (1969). The differences between the solutions of MODFLOW-2000 and MODFLOW-SP were nearly negligible when the slope was less than 0.27, and they were noticeable during the transient flow stage and vanished in steady state when the slope increased above 0.27. We established a model considering the vertical flow using COMSOL Multiphysics to test the robustness of constrains used in MODFLOW-SP. The results showed that streamlines quickly became parallel with the aquifer base except in the narrow regions near the boundaries when the initial flow was not parallel to the aquifer base. MODFLOW-SP can be used to predict the hydraulic head of an unconfined aquifer along the profile perpendicular to the aquifer base when the slope was smaller than 0.50. The errors associated with constrains used in MODFLOW-SP were small but noticeable when the slope increased to 0.75, and became significant for the slope of 1.0.

A new parameter estimation method for solute transport in a column.

To study contaminant transport in groundwater, an essential requirement is robust and accurate estimation of the transport parameters such as dispersion coefficient. The commonly used inverse error function method (IEFM) may cause unacceptable errors in dispersion coefficient estimation using the breakthrough curves (BTCs) data. We prove that the random error in the measured concentrations, which might be described by a normal distribution, would no longer follow the normal distribution after the IEFM transformation. In this study, we proposed a new method using the weighted least squares method (WLSM) to estimate the dispersion coefficient and velocity of groundwater. The weights were calculated based on the slope of the observed BTCs. We tested the new method against other methods such as genetic algorithm and CXTFIT program and found great agreement. This new method acknowledged different characteristics of solute transport at early, intermediate, and late time stages and divided BTCs into three sections for analysis. The developed method was applied to interpret three column tracer experiments by introducing continuous, constant-concentration of sodium chloride (NaCl) into columns filled with sand, gravel, and sand-gravel media. This study showed that IEFM performed well only when the observed data points were located in the linear (intermediate time) section of BTCs; it performed poorly when data points were in the early and late time stages. The new WLSM method, however, performed well for data points scattering over the entire BTCs and appeared promising in parameter estimation for solute transport in a column.