Urbanization increased river nitrogen export to western Taiwan Strait despite increased retention by nitrification and denitrification

Abstract(#br)Urban development and increased human activities impose major environmental stress on the receiving bodies of water. Although urban rivers have been recognized as hotspots of regional nitrogen (N) pollution, detailed measurements of river nutrient species in response to urbanization are rarely reported, so the impacts of urban development on N cycling processes and transport to coast remains unclear. Here we investigated the changes in N species (concentration, composition and isotope) and N functional genes between upstream and downstream sections of several rivers affected by urban development in western Taiwan Strait under various flow conditions (low, medium and high flow). Our results suggest that urban sewage (high ammonium) is the predominant substrate that stimulated nitrification and subsequently denitrification and gaseous N removal (N 2 O, N 2 ). Nitrifying and denitrifying functional genes increased their abundance along the urban rivers. There were hydrological and meteorological controls on urban rivers regulating changes in nitrogen retention between seasons. Overall, the enhanced microbe-driven N retention could not balance the increase of urban N loading. Consequently, urbanization increased riverine N export and caused other changes in nutrient supply such as changing the nutrient ratio (N:P:Si ratio), increasing the potential for eutrophication both in the river and in receiving coastal ecosystems

Possible Mechanisms of SARS-CoV2-Mediated Myocardial Injury

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has rapidly become a global health emergency. In addition to causing respiratory effects, SARS-CoV-2 can result in cardiac involvement leading to myocardial damage, which is increasingly being explored in the literature. Myocardial injury is an important pathogenic feature of COVID-19. The angiotensin-converting enzyme-2 receptor plays a key role in the pathogenesis of the virus, serving as a “bridge” allowing SARS-CoV-2 to invade the body. However, the exact mechanism underlying how SARS-CoV-2 causes myocardial injury remains unclear. This review summarizes the main possible mechanisms of myocardial injury in patients with COVID-19, including direct myocardial cell injury, microvascular dysfunction, cytokine responses and systemic inflammation, hypoxemia, stress responses, and drug-induced myocardial injury. Understanding of the underlying mechanisms would aid in proper identification and treatment of myocardial injury in patients with COVID-19

Smad7 enables STAT3 activation and promotes pluripotency independent of TGF-β signaling

TGF-β and related growth factors critically regulate cell potency and functions. Smad7 is induced by TGF-βs and inhibits the physiological functions of TGF-β signaling. This study describes an unexpected finding that Smad7 promotes self-renewal of embryonic stem cells (ESCs) in a manner independent of its inhibition on TGF-β signaling. Instead, Smad7 acts to induce activation of transcription factor signal transducers and activators of transcription 3 (STAT3) in ESCs. Smad7 activates STAT3 through its direct binding to the cytokine receptor upstream of STAT3 activation. In agreement with the role of STAT3 in maintaining ESC pluripotency, Smad7 promotes ESC self-renewal and induced pluripotent stem cell reprogramming. This finding illustrates a regulatory mechanism for Smad7 in maintaining pluripotency, and likely in cancer and inflammation

Porewater exchange drives the dissolved silicate export across the wetland‐estuarine continuum

Coastal wetlands are an important hotspot for nutrient cycling and transport from the land to the ocean. Silicon (Si) as a vital biogenic element affects plant growth and health of coastal ecosystems. The understanding of key factors and processes controlling dissolved silicate (DSi) exchange between the wetlands and coastal water has been limited due to the lack of measured data. We carried out intensive investigations of time-series DSi concentrations and porewater exchange across the Sediment-Water Interface (SWI) along a tidal creek with a mangrove-salt marsh gradient during neap and spring tides in 2020. Seasonal observations of surface water in a tidal creek and Zhangjiang Estuary (Fujian Province, China) were conducted from 2017 to 2020. The results showed that there was a net export of DSi from the mangroves to tidal creek with rates of 2.11 and 2.40 mmol m-2 d-1 in neap and spring tides respectively, suggesting the mangroves served as the source of DSi. However, the salt marshes had a net DSi import with one or two orders of magnitude lower than the export from the mangroves. DSi export across the wetland‐estuarine continuum was largely controlled by porewater exchange, groundwater geochemistry (pH, temperature) and plant root uptake. Groundwater in the mangroves has larger ratios of DSi : DIN (dissolved inorganic nitrogen) (2.5 ± 0.6) and DSi : DRP (dissolved reactive phosphorus) (1257 ± 35) compared with surface water. The net export of DSi from mangroves would modify the nutrient stoichiometry and mitigate the effects of reduced river DSi flux caused by damming on coastal ecosystem. This study provides new insights into the wetland Si cycling for sustaining coastal ecosystem health

Mitochondrial Dysfunction in Rheumatoid Arthritis

Rheumatoid arthritis, a chronic autoimmune disease with complex etiology, is characterized by excessive proliferation of synovial cells, massive production of inflammatory cells and cartilage destruction. Studies have shown that mitochondrial dysfunction plays an important role in promoting the occurrence of RA. Mitochondria with normal structure and function are essential for the normal survival of chondrocytes and synovial cells. Once mitochondrial function is destroyed, it will affect the survival, activation and differentiation of immune cells and non-immune cells involved in the pathogenesis of RA, thus leading to the occurrence of RA. However, the mechanism of mitochondrial dysfunction in RA remains unclear. This article reviews the method of mitochondrial dysfunction leading to RA, the effects of mitochondrial dysfunction on immune cells, the etiology of mitochondrial dysfunction in RA, and the pathology of mitochondrial dysfunction in RA. We also outline some drugs that can exert therapeutic effects on RA which are associated with modulating mitochondrial activity. The understanding and summary of mitochondrial dysfunction in RA may provide new research directions for pathological intervention and prevention of RA

Sporadic lymphangioleiomyomatosis with multiple atypical features: A case report and literature review

Lymphangioleiomyomatosis (LAM) is a rare, genetically determined, progressive interstitial lung disease, which almost exclusively affects women, especially at the childbearing age. The initial symptoms and radiographic changes in a patient with LAM are always associated with the respiratory system. Here, we present a case of mediastinal and abdominal LAM of a 22-year-old male, where LAM cells are negative for human melanoma black-45 ( HMB-45). The report of this uncharacterized LAM case will make a significant contribution to the realization of LAM associated clinical features, diagnostic approaches, and its afterward treatments

Enantioselective Extraction of Phenylalanine Enantiomers Using Environmentally Friendly Aqueous Two-Phase Systems

(1) Background: The environmentally friendly choline-amino acid ionic liquids (ChAAILs) and deep eutectic solvents (DESs) have been used as excellent alternatives to volatile organic compounds (VOCs) and ionic liquids (ILs) in recent years; (2) Methods: Thus, ChAAILs/salt and DESs/salt aqueous two-phase systems (ATPSs) were developed for the chiral extraction of phenylalanine enantiomers. The optimum ATPS of [Ch][L-Pro]/K3PO4 was chosen, and the influencing parameters were investigated, including ChAAILs concentration, salt concentration, chiral selector concentration, extraction temperature, phenylalanine concentration, and system pH; (3) Results: The phenylalanine enantiomers were mainly extracted into the top phase (ChAAIL-rich phase), meanwhile, the (S)-phenylalanine [(S)-Phe)] was preferentially recognized by the chiral selector in the top phase. The maximum separation factor (α) of 2.05 was obtained under the optimal conditions; and (4) Conclusions: This ATPS that was used for the chiral extraction of enantiomers is much more environmentally friendly, simple, and rapid, and has the potential to be used in the enantioselective extraction of other enantiomers