Abstract. Hydraulic tomography (i.e., a sequential aquifer test) has recently been proposed as a method for characterizing aquifer heterogeneity. During a hydraulic tomography experiment, water is sequentially pumped from or injected into an aquifer at different vertical portions or intervals of the aquifer. During each pumping or injection, hydraulic head responses of the aquifer at other intervals are monitored, yielding a set of head/discharge (or recharge) data. By sequentially pumping (or injecting) water at one interval and monitoring the steady state head responses at others, many head/discharge (recharge) data sets are obtained. In this study a sequential inverse approach is developed to interpret results of hydraulic tomography. The approach uses an iterative geostatistical inverse method to yield the effective hydraulic conductivity of an aquifer, conditioned on each set of head/discharge data. To efficiently include all the head/discharge data sets, a sequential conditioning method is employed. It uses the estimated hydraulic conductivity field and covariances, conditioned on the previous head/discharge data set, as prior information for next estimations using a new set of pumping data. This inverse approach was first applied to hypothetical, two-dimensional, heterogeneous aquifers to investigate the optimal sampling scheme for the hydraulic tomography, i.e., the design of well spacing, pumping, and monitoring locations. The effects of measurement errors and uncertainties in statistical parameters required by the inverse model were also investigated. Finally, the robustness of this inverse approach was demonstrated through its application to a hypothetical, three-dimensional, heterogeneous aquifer. IntroductionAccurate predictions of water and solute distributions and movement in geological formations require detailed knowledge of the spatial distribution of the hydraulic properties of the formations [Yeh, 1992[Yeh, , 1998]. Conventional aquifer tests (also known as pumping tests) assume aquifer homogeneity and yield effective hydraulic conductivity and the storage coefficient for an equivalent homogeneous aquifer. These hydraulic parameters are average properties of the aquifer over a large volume [Butler and Liu, 1993] and do not provide information of spatial distribution of the hydraulic conductivity within the volume. On the other hand, measurement of hydraulic conductivity of small-scale samples at a large number of locations is time-consuming, costly, and impractical.To circumvent these difficulties and to efficiently gain information of the spatial distribution of hydraulic conductivity, the geophysical tomography concept has recently been employed [Gottlieb and Dietrich, 1995; Butler et al., 1999]. Specifically, fully screened wells are segregated into many vertical intervals using packers. Water is pumped from or injected into an aquifer at one of the intervals to create a steady flow condition. Hydraulic head responses of the aquifer at other intervals are then monitored, yielding a set of ...

Metagenome of gut microbes has been implicated in metabolism, immunity, and health maintenance of its host. However, in most of previous studies, the microbiota was sampled from feces instead of gastrointestinal (GI) tract. In this study, we compared the microbial populations from feces at four different developmental stages and contents of four intestinal segments at maturity to examine the dynamic shift of microbiota in pigs and investigated whether adult porcine fecal samples could be used to represent samples of the GI tract. Analysis results revealed that the ratio of Firmicutes to Bacteroidetes from the feces of the older pigs (2-, 3-, 6- month) were 10 times higher compared to those from piglets (1-month). As the pigs matured, so did it seem that the composition of microbiome became more stable in feces. In adult pigs, there were significant differences in microbial profiles between the contents of the small intestine and large intestine. The dominant genera in the small intestine belonged to aerobe or facultative anaerobe categories, whereas the main genera in the large intestine were all anaerobes. Compared to the GI tract, the composition of microbiome was quite different in feces. The microbial profile in large intestine was more similar to feces than those in the small intestine, with the similarity of 0.75 and 0.38 on average, respectively. Microbial functions, predicted by metagenome profiles, showed the enrichment associated with metabolism pathway and metabolic disease in large intestine and feces while higher abundance of infectious disease, immune function disease, and cancer in small intestine. Fecal microbes also showed enriched function in metabolic pathways compared to microbes from pooled gut contents. Our study extended the understanding of dynamic shift of gut microbes during pig growth and also characterized the profiles of bacterial communities across GI tracts of mature pigs.

Cartilage extracellular matrix (ECM) is composed primarily of the network type II collagen (COLII) and an interlocking mesh of fibrous proteins and proteoglycans (PGs), hyaluronic acid (HA), and chondroitin sulfate (CS). Articular cartilage ECM plays a crucial role in regulating chondrocyte metabolism and functions, such as organized cytoskeleton through integrin-mediated signaling via cell-matrix interaction. Cell signaling through integrins regulates several chondrocyte functions, including differentiation, metabolism, matrix remodeling, responses to mechanical stimulation, and cell survival. The major signaling pathways that regulate chondrogenesis have been identified as wnt signal, nitric oxide (NO) signal, protein kinase C (PKC), and retinoic acid (RA) signal. Integrins are a large family of molecules that are central regulators in multicellular biology. They orchestrate cell-cell and cell-matrix adhesive interactions from embryonic development to mature tissue function. In this review, we emphasize the signaling molecule effect and the biomechanics effect of cartilage ECM on chondrogenesis.

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In mammals, the microbiota can be transmitted from the placenta, uterus, and vagina of the mother to the infant. Unlike mammals, development of the avian embryo is a process isolated from the mother and thus in the avian embryo the gut microbial developmental process remains elusive. To explore the establishment and inheritance of the gut microbiome in the avian embryo, we used the chicken as the model organism to investigate the gut microbial composition in embryos, chicks, and maternal hens. We observed: (1) 28 phyla and 162 genera of microbes in embryos where the dominated genus was Halomonas (79%). (2) 65 genera were core microbiota in all stages with 42% and 62% gut microbial genera of embryo were found in maternal hen and chick, respectively. There was a moderate correlation (0.40) between the embryo and maternal, and 0.52 between the embryo and chick at the family level. (3) Gut microbes that are involved in substance metabolism, infectious disease, and environmental adaptation are enriched in embryos, chicks, and maternal hens, respectively. (4) 94% genera of gut microbial composition were similar among three different chicken breeds which were maintained under similar conditions. Our findings provide evidence to support the hypothesis that part of the microbial colonizers harbored in early embryos were inherited from maternal hens, and the gut microbial abundance and diversity were influenced by environmental factors and host genetic variation during development.

[1] Two sandbox experiments were conducted to evaluate the performance of a sequential geostatistical inverse approach for hydraulic tomography in characterizing aquifer heterogeneity. One sandbox was packed with layered sands to represent a stratified aquifer, while the other was packed with discontinuous sand bodies of different shapes and sizes to represent a more complex and realistic heterogeneous aquifer. Parallel to the sandbox experiments, numerical experiments were conducted to assess the effects of measurement errors and uncertainties associated with laboratory data, and to diagnose the hydraulic conductivity estimates obtained from sandbox experiments. Results of this study show that our sequential inverse approach works well under realistic conditions, in spite of measurement errors and uncertainties associated with pumping rates, boundary conditions, pressure head measurements, and other parameters required by our model. The tomography was found to be ineffective if abundant head measurements were collected at closely spaced intervals in a highly stratified aquifer. On the other hand, it was found to be beneficial when pressure head measurements were limited and the geological structure was discontinuous.

We have previously reported a natural, human cartilage ECM (extracellular matrix)-derived three-dimensional (3D) porous acellular scaffold for in vivo cartilage tissue engineering in nude mice. However, the in vivo repair effects of this scaffold are still unknown. The aim of this study was to further explore the feasibility of application of cell-loaded scaffolds, using autologous adipose-derived stem cells (ADSCs), for cartilage defect repair in rabbits. A defect 4 mm in diameter was created on the patellar groove of the femur in both knees, and was repaired with the chondrogenically induced ADSC-scaffold constructs (group A) or the scaffold alone (group B); defects without treatment were used as controls (group C). The results showed that in group A all defects were fully filled with repair tissue and at 6 months post-surgery most of the repair site was filled with hyaline cartilage. In contrast, in group B all defects were partially filled with repair tissue, but only half of the repair tissue was hyaline cartilage. Defects were only filled with fibrotic tissue in group C. Indeed, histological grading score analysis revealed that an average score in group A was higher than in groups B and C. GAG and type II collagen content and biomechanical property detection showed that the group A levels approached those of normal cartilage. In conclusion, ADSC-loaded cartilage ECM scaffolds induced cartilage repair tissue comparable to native cartilage in terms of mechanical properties and biochemical components.

Macrophages (Mφ) are primary innate immune cells that exhibit diverse functions in response to different pathogens or stimuli, and they are extensively involved in the pathology of various diseases. Extracellular vesicles (EVs) are small vesicles released by live cells. As vital messengers, macrophage-derived EVs (Mφ-EVs) can transfer multiple types of bioactive molecules from macrophages to recipient cells, modulating the biological function of recipient cells. In recent years, Mφ-EVs have emerged as vital mediators not only in the pathology of multiple diseases such as inflammatory diseases, fibrosis and cancers, but also as mediators of beneficial effects in immunoregulation, cancer therapy, infectious defense, and tissue repair. Although many investigations have been performed to explore the diverse functions of Mφ-EVs in disease pathology and intervention, few studies have comprehensively summarized their detailed biological roles as currently understood. In this review, we briefly introduced an overview of macrophage and EV biology, and primarily focusing on current findings and future perspectives with respect to the pathological and therapeutic effects of Mφ-EVs in various diseases.