Hydrodynamic sorting controls the transport and hampers source identification of terrigenous organic matter: A case study in East China Sea inner shelf and its implication.

Transport of terrigenous organic matter (TerOM) in marginal seas plays an important role in marine carbon cycle which is closely related to global climate change. Suspended particulates in East China Sea (ECS) inner shelf are subject to strong influence of seasonally varied Zhe-Min Coastal Current (ZMCC) and Taiwan Warm Current (TWC). Transport of TerOM attached to the mineral particulates is therefore largely dependent on these hydrodynamic conditions. To address the transport pattern of TerOM in highly dynamic marginal seas and its implication, sediment samples were collected from ECS inner shelf and fractionated by water elutriation to simulate the hydrodynamic sorting process. Lignin phenols were determined for each fraction. The abundance of C phenols preferentially concentrated in the finer fractions, which is believed as a collective effect of hydrodynamic sorting, diagenetic reactivity and association preference of C phenols with finer sediments. In contrast to the expectation, sediments at the southernmost site did not have the highest mass percentage for the finest fraction, the lowest lignin abundance and the highest degradation status. Combining the results of lignin parameters with seawater temperature and salinity profiles, it is proposed that sediments are transported along the inner shelf southward in winter and northward in summer to some extent with the influence of seasonally varied ZMCC and TWC, induced by the seasonality of East Asia Monsoon (EAM). Finer grained sediments are more susceptible to this process. This transport pattern, which was only reported previously in ocean modeling, was firstly supported by the observation of lignin biomarkers. It is suggested that cross-shelf transport of sediments in ECS seems to be possible, but is complicated and is also affected by the seasonal variation of EAM. This study improved the understanding of hydrodynamic sorting on the transport of TerOM and carbon cycling in the marine system.

Interactions Between Different Selenium Compounds and Essential Trace Elements Involved in the Antioxidant System of Laying Hens.

The purpose of this study was to investigate the interactions between different selenium (Se) compounds including sodium selenite (SS), selenium-enriched yeast (SY), and nano-selenium (NS) and various essential trace elements involved in the antioxidant systems, and to evaluate the effects on laying performance and egg quality. A total of 288 21-week-old Hyline Sophie hens were allotted to four dietary treatments: (1) basal diet without Se supplementation; (2) basal diet supplemented with 0.3 mg/kg Se of SS; (3) basal diet supplemented with 0.3 mg/kg Se of SY; (4) basal diet supplemented with 0.3 mg/kg Se of NS. Each treatment had eight replicates with nine hens per replicate. The trial lasted for 35 days. Results demonstrated that NS supplementation decreased the egg production (EP) and increased the feed conversion rate (FCR) and eggshell thickness and that SY changed the egg shape index (p < 0.05). Supplementation with three Se compounds significantly increased serum Se concentration and glutathione peroxidase (GSH-Px) activity in all treatment groups, as well as total superoxide dismutase (T-SOD) activity in the SY and NS groups. Yolk iron (Fe) and copper (Cu) concentrations in the NS group were also increased with Se supplementation. While the serum zinc (Zn) concentration decreased in the NS and SY groups, as well as the yolk manganese (Mn) concentration in the SY group. And the total antioxidant capability (T-AOC) of yolk with 3 days of storage in the SY and NS groups, malondialdehyde (MDA) value in the NS group, and the T-SOD activity and MDA value of yolk with 10 days of storage in the SY group also decreased. Thus, the source of Se compounds may influence the balance between Se and other trace elements including Zn, Mn, Fe, and Cu, which is important for proper antioxidant defense in blood and egg yolk of laying hens.

The combined effects of X-ray radiation and hindlimb suspension on bone loss.

Outer space is a complex environment with various phenomena that negatively affect bone metabolism, including microgravity and highly energized ionizing radiation. In the present study, we used four groups of male Wistar rats treated with or without four-week hindlimb suspension after 4 Gy of X-rays to test whether there is a combined effect for hindlimb suspension and X-ray radiation. We tested trabecular parameters and some cytokines of the bone as leading indicators of bone metabolism. The results showed that hindlimb suspension and X-ray radiation could cause a significant increase in bone loss. Hindlimb suspension caused a 56.6% bone loss (P = 0.036), while X-ray radiation caused a 30.7% (P = 0.041) bone loss when compared with the control group. The combined factors of hindlimb suspension and X-rays exerted a combined effect on bone mass, with a reduction of 64.8% (P = 0.003).

MicroRNAs regulate bone metabolism.

Osteoporosis is caused by an unbalance between bone formation and bone resorption. Bone homeostasis is regulated by intricate mechanisms. Recently, a novel class of regulatory factors termed microRNAs (miRNAs) has been found to play a crucial role in cell cycle control, apoptosis and other cellular processes including metabolism and differentiation. Published data have shown that some miRNAs regulate bone homeostasis, including bone formation, resorption, remodeling, repair and bone-related disease, by regulating the expression of certain cytokines and transcription factors. This review highlights the current knowledge of miRNAs and their involvement in the regulation of bone formation, bone resorption and the pathways regulating the progression of osteoporosis.