Phosphate Removal in Relation to Structural Development of Humic Acid-Iron Coprecipitates.

Precipitation of Fe-hydroxide (FH) critically influences the sequestration of PO4 and organic matter (OM). While coatings of pre-sorbed OM block FH surfaces and decrease the PO4 adsorption capacity, little is known about how OM/Fe coprecipitation influences the PO4 adsorption. We aimed to determine the PO4 adsorption behaviors on humic acid (HA)-Fe coprecipitates in relation to surface and structural characteristics as affected by HA types and C/(C + Fe) ratios using the Fe and P X-ray absorption spectroscopy. With increasing C/(C + Fe) ratios, the indiscernible changes in the proportion of near-surface C for coprecipitates containing HA enriched in polar functional groups implied a relatively homogeneous distribution between C and Fe domains. Wherein PO4 adsorbed on FH dominated the P inventory on coprecipitates, yielding PO4 sorption properties nearly equivalent to that of pure FH. Structural disruptions of FH caused by highly associations with polar functional groups of HA enhanced the C solubilisation. While polar functional groups were limited, coprecipitates consisted of core FH with surface outgrowth of HA. Although surface-attached HA that was vulnerable to solubilisation provided alternatively sites for PO4 via ternary complex formation with Fe bridges, it also blocked FH surfaces, leading to a decrease in PO4 adsorption.

M1 macrophages decrease in the deciduae from normal pregnancies but not from spontaneous abortions or unexplained recurrent spontaneous abortions.

BACKGROUND/PURPOSE: To investigate the M1/M2 polarity of macrophages in the endometrium among different menstrual cycles, normal and abnormal pregnancies, and unexplained recurrent spontaneous abortions (RSAs). METHODS: Endometrial tissue was obtained from 43 patients undergoing hysterectomy, either in the follicular phase (Group 1, n = 23) or in the luteal phase (Group 2, n = 20). In addition, decidual tissue was obtained from 53 pregnant women during the first trimester, either of normal pregnancies (Group 3, n = 12) or abnormal pregnancies (Group 4: spontaneous abortions, n = 20; Group 5: unexplained RSA, n = 21). Using immunofluorescence to examine the M1 and M2 macrophages in the endometrium and deciduae from cases with different menstrual phases and various pregnancy outcomes, respectively, we endeavored to learn the possible pathophysiology of abortions. RESULTS: M1 macrophages were abundant in the deciduae of spontaneous abortions and unexplained RSA, whereas the frequency of M2 macrophages was significantly higher in the endometrium of luteal phase and normal pregnancies. CONCLUSION: M2 polarization is important for early successful pregnancies in humans.