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Surface meltwater can be retained in an ice sheet if it infiltrates the firn and refreezes. This is an important mass balance process for the Greenland Ice Sheet, reducing meltwater runoff and associated sea‐level rise. The processes of meltwater infiltration and refreezing are not fully understood, however, and remain difficult to monitor remotely. We deployed vertical arrays of thermistors and time‐domain reflectometry (TDR) probes to 4‐m depth in the firn to continuously monitor meltwater infiltration and refreezing processes at DYE‐2, Greenland. The observations provide a detailed picture of the coupled thermal and hydrological evolution of the firn through the 2016 melt season, including estimates of firn water content. The thaw and wetting fronts reached a maximum depth of 1.8 m, with meltwater infiltration concentrated in four main pulses of melting and subsurface warming that reached progressively deeper into the firn. The observations were used to constrain a coupled model of firn thermodynamics and hydrology, which was then run over the period 1950–2020, driven by meteorological forcing from GC‐Net station data and ERA5 climate reanalyses. Model results suggest that decadal‐scale firn evolution at DYE‐2 is strongly influenced by extreme melt seasons such as those of 1968, 2012, and 2019, when meltwater infiltration reached depths of 6–7 m. Extreme melt years drive increases in firn temperature, ice content, and density, reducing firn meltwater retention capacity. Such processes are likely to govern future meltwater retention as the percolation zone extends to higher elevations in Greenland in the coming decades. Plain Language Summary: On polar ice sheets, the vast majority of surface meltwater either runs off to the ocean or is refrozen in porous layers of snow and firn. These processes are important to understand across the Greenland Ice Sheet because they influence how much meltwater contributes to sea level rise versus being retained within the ice sheet in any given year. However, the subsurface nature of meltwater percolation and refreezing makes these processes difficult to accurately monitor, and the conditions that control meltwater retention are also evolving with the changing climate. In the spring of 2016, we deployed a novel array of buried temperature and wetness sensors in the snow and firn at the DYE‐2 site in Greenland to monitor the infiltration and refreezing of meltwater in firn, as well as a meteorological station at the surface to collect weather and radiation data. The station measured the evolution of firn structure and temperature over a full annual cycle of melting and refreezing. We used the field measurements to constrain a computer model that simulates firn density, melt, and refreezing processes at the same location in Greenland from 1950 through 2020, based upon historical climate reconstructions. We find that, while large summer melt events appear periodically in the long‐term record, including a notable melt summer in 1968, recent extreme melt events at DYE‐2 in 2012 and 2019 are altering subsurface firn properties in ways that will reduce meltwater retention capacity in Greenland's percolation zone in a warming Arctic climate. Key Points: Time‐domain reflectometry provided continuous monitoring of firn liquid water content and meltwater infiltration through a melt seasonA simple coupled model of firn thermodynamics and hydrology reproduces the observed evolution of the firn thawing and wetting frontsModeling from 1950 to 2020 indicates that extreme melt seasons govern trends in firn temperature, density, and ice content at DYE‐2 [ABSTRACT FROM AUTHOR]

This paper presents a fully coupled plasticity model for the rigorous analysis of fluid flow and solid skeleton deformation in variably saturated porous media. The flow deformation behaviour of unsaturated soils is described through the simultaneous solution of governing partial differential equations, including the equilibrium equation and the continuity equations of pore fluids. The coupling between solid and fluid phases is established based on the effective stress concept with the effective stress parameter as a function of suction. The elasto-plastic behaviour of geomaterials is formulated using the bounding surface theory. The fully coupled flow deformation framework along with the UNSW bounding surface constitutivelaw are implemented into COMSOL Multiphysics commercial software to simulate the results of several laboratory tests conducted on soils with different degrees of saturation under various drainage conditions and loading paths. The close agreement between the numerical solutions and experimental data from the literature indicates the good performance of this new elastic-plastic unsaturated model and emphasises its capability to capture the different characteristic features of response of soils with a variety of saturation degrees and over-consolidation ratios.

Hydraulic fracturing (HF) of underground formations has widely been used in different fields of engineering. Despite the technological advances in techniques of in situ HF, the industry uses semi-analytical tools to design HF treatment. This is due to the complex interaction among various mechanisms involved in this process, so that for thorough simulations of HF operations a fully coupled numerical model is required. In this study, using element-free Galerkin (EFG) mesh-less method, a new formulation for numerical modeling of hydraulic fracture propagation in porous media is developed. This numerical approach, which is based on the simultaneous solution of equilibrium and continuity equations, considers the hydro-mechanical coupling between the crack and its surrounding porous medium. Therefore, the developed EFG model is capable of simulating fluid leak-off and fluid lag phenomena. To create the discrete equation system, the Galerkin technique is applied, and the essential boundary conditions are imposed via penalty method. Then, the resultant constrained integral equations are discretized in space using EFG shape functions. For temporal discretization, a fully implicit scheme is employed. The final set of algebraic equations that forms a non-linear equation system is solved using the direct iterative procedure. Modeling of cracks is performed on the basis of linear elastic fracture mechanics, and for this purpose, the so-called diffraction method is employed. For verification of the model, a number of problems are solved. According to the obtained results, the developed EFG computer program can successfully be applied for simulating the complex process of hydraulic fracture propagation in porous media. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background and Objectives The evaluation of the number, potential, and functional capacity of cord blood stem cells after long term storage is essential for their therapeutic uses in hematological malignancies and nonmalignancies. Therefore, this study was aimed to assess the quality of cord blood units stored in Royan public cord blood bank, before and after cryopreservation. Materials and Methods To check the quality of cryopreserverd cord blood units, the total number of cells, percentage of viable cells, colony-forming ability, the number of CD34+ cells before and after freezing were examined on 50 samples Results Our results determined that the mean value of the total nucleated cells in 50 cord blood samples was 7.6 × 108 ± 1.12 × 108. The number and viability of mononuclear cells as well as colony forming potential significantly decreased after cryopreservation; however, the count of viable CD34+ cells did not significant changes post thawing. There was no significant correlation between the numbers of nucleated cells and CD34+ cells. Conclusions Increasing the storage time significantly reduces the number of nucleated cells and differentiation potential of hematopoietic stem cells rather than the number of CD34+ cells. Improved cryopreservation techniques are necessary to maintain the function of cord blood stem cells. [ABSTRACT FROM AUTHOR]

The simulation of fractured reservoir is conventionally performed by using dual porosity formulation in which the type of transfer function may be critical. Over the past few years, various models with their strength and weakness have been developed to account for matrix-fracture interporosity flow. However, some of them are unable to simulate some mechanisms like gravity drainage. In this work, the most well-known transfer functions have been examined for simulation of the gravity drainage in a single block model and an improvement has been introduced to modify them. The validation of the developed approach have been done by using fine grid simulation. [ABSTRACT FROM AUTHOR]

Tehran as the biggest city of Iran with a population of more than 10 millions has potentially high pollutant exposures of gas oil and gasoline combustion from vehicles that are commuting in the highways every day. The vehicle exhausts contain polycyclic aromatic hydrocarbons, which are produced by incomplete combustion and can be directly deposited in the environment. In the present study, the presence of polycyclic aromatic hydrocarbons contamination in the collected samples of a western highway in Tehran was investigated. The studied location was a busy highway in Tehran. High performance liquid chromatography equipped with florescence detector was used for determination of polycyclic aromatic hydrocarbons concentrations in the studied samples. Total concentration of the ten studied polycyclic aromatic hydrocarbons compounds ranged from 11107 to 24342 ng/g dry weight in the dust samples and increased from 164 to 2886 ng/g dry weight in the soil samples taken from 300 m and middle of the highway, respectively. Also the average of Σ PAHs was 1759 ng/L in the water samples of pools in parks near the highway. The obtained results indicated that polycyclic aromatic hydrocarbons contamination levels were very high in the vicinity of the highway. [ABSTRACT FROM AUTHOR]

This article reports the first application of the Quasi-Monte Carlo (QMC) method for estimation of the pseudo relative permeability curves. In this regards, the performance of several meta-heuristics algorithms have also been compared versus QMC, including the Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and the Artificial Bee Colony (ABC). The mechanism of minimizing the objective-function has been studied, for each method. The QMC has outperformed its counterparts in terms of accuracy and efficiently sweeping the entire search domain. Nevertheless, its computational time requirement is obtained in excess to the meta-heuristics algorithms.

The article discusses a study related to investigation of the changing immune profile of the skin after sex-mismatched allogeneic haematopoietic stem cell transplant using immunohistochemistry and fluorescence in situ hybridization (FISH). Topics discussed include presence of donor-derived cells, increased CD8+ cells in the epidermis at the time of acute graft-versus-host disease (aGVHD) diagnosis and the FISH technique as useful for highlighting immune cell population dynamics.

Low-dose TSE can rapidly attain cutaneous control in MF/SS, though duration is limited. Hypofractionated (HF) TSE is gaining interest due to shorter treatment schedules and potential for decreased lymphotoxicity. However, the impact of standard fractionation (SF) or HF TSE on hematologic parameters is poorly characterized, and in advanced MF/SS cytopenias may preclude or delay initiation of critical systemic therapy. Here, we compare hematologic toxicities among SF and HF regimens. From 2015-2023, 111 patients (pts) underwent 121 courses of SF or HF TSE. SF was defined as 1 Gy/fraction totaling 12 Gy, and HF as 1.5-2 Gy/fraction totaling 12 Gy. Complete blood counts were recorded at the following intervals: 1 month (mo) pre-RT (3 mo pre-RT when 1 mo data were unavailable), -1 week through 1 mo post final RT fraction, >1-2 mo, and >2-3 mo. Toxicities were graded per CTCAEv5, with grade 1-2 categorized as low grade (LG) and 3-4 as high grade (HG). There were 104 SF and 17 HF courses of TSE, with median follow up of 21 mo (0-86). Cohorts were well balanced other than ECOG performance status (PS) 0-1 vs. 2-4, with poorer PS in the HF group (p = 0.03). At baseline, 16% had leukopenia (1% HG), 69% had anemia (all LG), 11% had thrombocytopenia (all LG), 45% had lymphopenia (17% HG), and 8% had neutropenia (1% HG). There were no significant differences in pre-TSE cytopenias between cohorts. Cytopenia rates post TSE did not differ between cohorts (see Table 1). HG lymphopenias were observed at all time points among the SF and HF cohorts: pre-TSE 16% vs 25%, -1 week-1mo 23% vs 33%, > 1 mo-2 mo 19% vs 29%, and > 2-3 mo 11% vs 20% (p > 0.05). Best cutaneous response rates did not significantly differ between SF and HF groups: CR 18% vs 18%, PR 73% vs 77%, SD 5% vs 0%, POD 1% vs 6%, unknown 3% vs 0%, respectively (p = 0.5). Median time to best response was 1.9 vs 2.8 months respectively (p = 0.2). Median time to disease progression was 5.8 vs 6.4 months, respectively (p = 0.8). MF/SS pts presenting for TSE have high rates of cytopenias at baseline which persist following TSE. Cytopenias following TSE and response rates did not differ between SF and HF regimens. Thus, TSE for cutaneous control using SF or HF appears unlikely to prevent subsequent initiation of systemic therapy due to hematologic toxicity. Table 1. Cytopenias following TSE by fractionation regimen. [ABSTRACT FROM AUTHOR]