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Background Hepatic stellate cells (HSCs) are known to play a fundamental role in the progression of liver fibrosis. Once HSCs are activated, they are involved in proliferation, migration, and contractility which are characteristics of liver fibrogenesis. Recent studies have shown that irisin, a myokine secreted during physical exercise, has a protective effect in various metabolic diseases, especially in renal fibrosis. However, whether irisin is involved in HSC activation and other processes associated with liver fibrosis has not yet been investigated. In this study, we reveal the role of irisin in HSC activation as well as in proliferation, migration, and contractile properties of HSCs in vitro. Methods LX-2 cells, immortalized human HSCs, were treated with transforming growth factor beta 1 (TGF-β1), a core regulator of HSC fibrosis, with or without irisin, and markers of the aforementioned processes were analyzed. Further, an inflammatory response was stimulated with TGF-β1 and lipopolysaccharide (LPS) in combination with irisin and the expression of cytokines was measured. Results Recombinant irisin significantly suppressed the expression of TGF-β1-stimulated fibrosis markers including alpha-smooth muscle actin and collagen type 1 alpha 1 and prevented the TGF-β1-induced proliferation, migration, and contractility of LX-2 cells. Additionally, irisin ameliorated the production of interleukin-6 (IL-6) and IL-1β induced by TGF-β1 and LPS treatments. Conclusion These findings suggested that irisin potently improved the progression of hepatic fibrosis by regulating HSC activation, proliferation, migration, contractility, and HSC-mediated production of inflammatory cytokine.

Operating parameters for the two-stage nitritation/anammox (PN/A) process in mainstream flows from lab-scale to pilot-scale were investigated. In the batch experiment, the specific activities of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) were fitted with a Monod model, and the oxygen affinity of NOB was higher than that of AOB. Nevertheless, dissolved oxygen concentrations higher than 2.0 mgO

The preservation efficiency of mainstream (M-ANA) and sidestream anaerobic ammonium oxidation (anammox) (S-ANA) were evaluated based on their activation energy (E

The effects of C/N ratio in mainstream partial nitritation (PN)-anaerobic ammonia oxidation (ANAMMOX) considering competitive relationship of aerobic microbes competing for oxygen were investigated. Thy system was operated for 501 d with various C/N ratio. Competitive growth of aerobic heterotrophic bacteria (AHB) at ≥ 1 of C/N ratio acted effectively on the selective inhibition of nitrite-oxidizing bacteria (NOB) while contributing to stable PN-A. In-depth kinetic analysis indicated oxygen affinity of aerobic microbes was in the order of AHB ammonia-oxidizing bacteria (AOB) NOB. In addition, potential of denitritation by AHB could contributed to improving nitrogen removal up to 87.5 ± 4.3%. AHB was comparatively clustered into two groups with a C/N ratio of 1. Nitrosomonas sp. PY1 became predominant while Nitrospira spp. were the major NOB. The potential of AHB in establishing selective inhibition of NOB was identified, which could be a novel approach to stabilze the mainstream PN-A.

A partial nitritation (PN)/anaerobic ammonium oxidation (ANAMMOX) process in sequencing batch reactor (SBR) was successfully developed to treat high-strength ammonium wastewater. The feed distribution in the SBR cycle and sub-cycles was considered as the main operating strategy, and was optimized using a response surface methodology (RSM)-based optimization technique. In the SBR cycle, the maximum nitrogen removal rate (NRR) of 0.79 ± 0.01 kg m−3 d−1 was achieved by applying a feed distribution strategy that considered the kinetic characteristics of ANAMMOX and ammonia oxidizing bacteria (AOB). However, this strategy negatively affected the nitrogen removal efficiency (NRE) due to alkalinity loss. Therefore, the feed distribution in the SBR sub-cycles with respect to the NRE and the NRR was further studied. The nitrogen removal performance was optimized in the optimum region and an NRE of 88% and an NRR of 0.84 kg m−3 d−1 were achieved. The optimized model was verified in confirmation test. The RSM-based optimization results provide insights into the feed distribution strategy for achieving single-stage PN/ANAMMOX SBR operation.

The long-term preservation of anaerobic ammonium oxidation (anammox) microorganisms via vacuum lyophilization process would help commercialize the technique. In this study, vacuum lyophilization was evaluated for the cost-effective long-term preservation of such microorganisms. Skim milk was found to be the most effective cryoprotectant for maintaining the physiological properties (heme c, EPS, and the PN/PS ratio) of anammox microorganisms. Conversely, the vacuum lyophilization technique was shown to cause serious damage to the quorum sensing (QS) system of anammox, so that anammox activity was not adequately recovered afterwards. To overcome this limitation, activation of the AHL-mediated QS system were applied to the vacuum lyophilization process. Endogenous (i.e., fresh anammox sludge of 10%) and exogenous (i.e., C6-HSL of 60 mg/L) QS autoinducers significantly increased anammox activity to 88.2 ± 12.2 and 130.0 ± 12.2 mgTN/gVSS/d, respectively, after 56 d of reactivation. In addition, nitrogen removal potentials were estimated to be 123.5 and 87.5 gTN/m

This paper describes the new concept of the mainstream partial nitritation (PN)-anaerobic ammonium oxidation (ANAMMOX) combined with a high-temperature shock strategy for the selective recovery of ammonia-oxidizing bacteria (AOB) activity. In the preliminary test, the temperature shock condition for PN was optimized (60 °C and > 20 min). Based on this, the implementation strategy in a continuous stirred tank reactor (CSTR) system was studied further, and the polyvinyl alcohol (PVA)/sodium alginate carrier exposure ratio (ER) and dissolved oxygen (DO) concentration were considered as primary variables. The AOB activity was recovered selectively when the ER of the carrier ranged from 20 to 40%, and the DO was higher than 2.3 mg O2/L. This was not the case for nitrite-oxidizing bacteria (NOB) (AOB: 1.17±0.1 gNH4+-N/LCarrier/d, NOB: 0.34±0.1 gNO3--N/LCarrier/d). As a result, the activity of AOB was recovered selectively with a decrease in Nitrospira spp., which was verified by kinetic and microbial analyses for the AOB (KS, DO = 3.89 mgO2/L) and NOB (KS, DO = 1.14 mgO2/L). Eventually, the mainstream PN-ANAMMOX was achieved with a nitrogen removal efficiency of 81.5±3.3% for 95 days. The findings provide insight to establishing a stable mainstream PN-ANAMMOX process using a high-temperature shock strategy.

The lack of seed sludges for Ammonium Oxidizing Bacteria (AOB) and slow-growing ANaerobic AMMonium OXidation (ANAMMOX) bacteria is one of the major problem for large-scale application. In this study, 24m3 of single-stage SBR (Sequencing Batch Reactor) was operated to remove nitrogen from reject water using AOB and ANAMMOX bacteria cultivated from activated sludge in the field. The ANAMMOX activity was found after 44 days of cultivation in the ANAMMOX cultivation reactor, and then 0.66 kg N/m3/d of the nitrogen removal rate was achieved at 0.78 kg N/m3/d of the nitrogen loading rate at 153 days of cultivation. The AOB cultivation reactor showed 0.2 kg N/m3/d of nitrite production rate at 0.4 kg N/m3/d of nitrogen loading rate after 36 days of operation. The cultivated ANAMMOX bacteria and AOB was mixed into the single-stage SBR. The feed distribution was applied to remove total nitrogen stably in the single-stage SBR. The nitrogen removal rate in the single-stage SBR was gradually enhanced with an increase of specific activities of both AOB and ANAMMOX bacteria by showing 0.49 kg N/m3/d of the nitrogen removal rate at 0.56 kg N/m3/d of the nitrogen loading rate at 54 days of operation.

The key operating parameters for improving the nitrogen removal rate (NRR) in a sequencing batch reactor (SBR) for deammonification were investigated. The major operating strategies were the coexistence between deammonification and denitrification with a carbon/nitrogen (C/N) ratio of 0.5 and the control of the number of sub-cycles based on substrate concentration for anaerobic ammonium oxidation (ANAMMOX) and ammonium oxidizing bacteria (AOB). In the study, denitrification with the addition of an organic source was beneficial for improving the NRR from 0.5 ± 0.01 kg N m−3 d−1 to 0.53 ± 0.01 kg N m−3 d−1 by removing the nitrate produced as a by-product of ANAMMOX. Unlike the gradual increase of the specific activity for AOB, the specific ANAMMOX activity (SAA) was maximized when an ammonium concentration supplied after sub-feeding phase was increased from 20 to 100 mg L−1, which increased the NRR from 0.53 ± 0.01 kg N m−3 d−1 to 0.79 ± 0.01 kg N m−3 d−1. This result suggested that the SAA is more important than the specific activity for AOB as a parameter for controlling the NRR in the single-stage deammonification. In the whole experimental period, the granule size smaller than 100 μm accounted for 52.5 ± 0.9%, making the largest contribution to the activity for AOB and denitrifiers. However, the granule size larger than 100 μm made the greatest contribution (83.8 ± 0.5%) to SAA. The feasibility of using the derivate of pH and OPR as indirect parameters to control the NRR was verified.

Conventional sequencing batch reactors (SBRs) have been developed based on nitrogen removal efficiency rather than the effluent nitrogen concentration as a design factor. The purpose of this study was to achieve the target effluent total nitrogen (TN) concentration regardless of the influent nitrogen concentration at 10 m3 pilot SBR. The desired nitrogen removal efficiency was achieved by distributing the influent one to four times in one cycle, but effluent TN concentration fluctuated as the influent nitrogen concentration varied. To achieve the target effluent TN concentration, the residual ammonia concentration after sub-feeding was adjusted to the target nitrogen concentration based on real-time ammonia sensing. When the residual ammonia concentration after sub-feeding was set at 10 or 5 mg NH4+-N L−1, the effluent TN concentration was 9.3 ± 0.6 or 4.6 ± 0.3 mg L−1, respectively, regardless of the influent TN concentration. Furthermore, complete nitrification was achieved under low temperature, from 7.2 to 13.1 °C, by controlling the aeration phase end point based on the real-time ammonia sensing. However, when the residual nitrate concentration was adjusted to a low level, the total phosphorus (TP) removal efficiency was high owing to an increase of phosphate release activity by polyphosphate accumulating organisms.

This study investigated long-term deammonification operation, of 400 days, utilizing PVA/alginate carriers prepared with the addition of foaming agent (FA) adjusted from 0 to 1.2% (F-0 to F-1.2). FTIR spectra showed variations in the extent of crosslinking in the surface and the core areas of carriers. FA addition improved the already low crosslinking in the core areas and porosity in the surface areas, yielding higher endurance to internally produced gas. In the start-up period of continuous test, FA addition favored deammonification bacteria over denitrifiers. Increasing the FA decreased the extent and duration of heterotrophic denitrification that was superseded by deammonification after 30 d of operation. After 100 d, F-0.6 had the highest deammonification to denitrification ratio and gave a nitrogen removal rate (NRR) of 3.2 kg N.m−3.d−1 at 317 d of operation. Also, the 16S rRNA gene concentration of the deammonification bacteria was highest in F-0.6, which corresponded with the specific anammox activity (SAA) results. Overall, the improved PVA/alginate carriers gave higher SAA and deammonification bacteria concentration resulting in a stable long-term deammonification operation with high NRR.

In order to achieve an appropriate effluent ratio of ammonium and nitrite as an influent of the anaerobic ammonium oxidation process, the optimum conditions for the partial nitritation in a continuous stirred tank reactor (CSTR) were investigated using real reject water. Hydraulic retention time (HRT) and influent alkalinity (HCO3-)/NH4+-N ratio were major factors that greatly influenced the partial nitritation. As a result of continuous operation, ammonium conversion efficiency (ACE) and effluent nitrite to ammonium ratio (NAR) could be achieved at the HRT of 19 h corresponding to 0.71 kg/m3/d of nitrogen loading rate (NLR). Thereafter, the influent HCO3-/NH4+-N ratio was adjusted from 0.5 to 2, and as a result, the optimum partial nitritation efficiency was maintained when the influent HCO3-/NH4+-N ratio was one. The suitability of the determined operating conditions was verified in a CSTR over 30 d of operation time.

This study investigated innovative start-up strategies of a pilot-scale sequencing batch reactor (SBR) for single-stage deammonification using activated sludge as the sole inoculum source. In 24 m3 aerobic oxidizing bacteria cultivation plant, nitrogen loss efficiency was suggested to be an indicator for determining duration of cultivation. In 12 m3 ANAMMOX (ANaerobic AMMonium OXidation) cultivation plant, combined strategy (sequential fed-batch and continuous modes) was adopted to promote ANAMMOX activity from activated sludge. Both the cultivated sludge were inoculated in 24 m3 pilot-plant for single-stage SBR with deammonification. The feed distribution strategy was used to cultivate ANAMMOX bacteria selectively resulting in nitrogen removal rate of 0.73 kg/m3/d and nitrogen removal efficiency of 86.5 ± 1.9% within 254 days. Candidatus Brocadia sp. 40 was enriched from undetectable to 22.7% relative abundance. These findings indicated that fast start-up of the deammonification process was possible without ANAMMOX seed sludge in pilot-scale reactor with various variables.

Industrial effluent was tested for softening and polyacrylamide (PAC) residue removal and correlated with the Langelier saturation index (LSI). Contrary to previously reported methods, the initial LSI (LSIin) was calculated using the pre-reaction pH, the inherent alkalinities of the original wastewater and the alkalinities added during softening, under the assumption that no physical or chemical reaction had started. During the softening optimization tests, higher LSIin predicted efficient softening, which was further confirmed by lower final LSI (LSIfin). The NaOH dose adjustment was more effective with 100% softening than that achieved by adjusting initial pH. Calcite seeding was more effective at pH 7 with lower LSIin in the range −2 to 2 than that at pH 10 with LSIin in the range 1–4.7. During NaOH dose optimization, LSIin was higher and LSIfin was lower at a higher soda ash to hardness molar ratio of 1.3:1 than that at a lower ratio of 1:1. Compact accelerated precipitation softening process ...

Recently, one of the main research on the power distribution system is the microgrid. The microgrid is a combination of power sources and loads, which is controllable and has separable connection. The main objective of microgrid is the deployment of the renewable clean energy and the enhancement of load-side reliability. The modern power sources and loads have DC I/O interfaces, which is the major advantage of DC microgrid compared to the conventional AC grid. The components in the microgrid have diverse features, so there is need of proper coordination control. For achieving economic feature, the active power of renewable energy resources is regarded as major control parameter and the whole operation modes of DC microgrid are defined, and the proper operations of each component are described. From the inherent characteristics of DC, there are two control variables: voltage and active power. Through analysis of operation modes, it is possible to determine exact control objectives and optimized voltage & power control strategy in each mode. Because of consideration of whole operation modes, regardless of the number and capacity of components, this coordination control method can be used without modification. This paper defines operation mode of DC microgrid with several DC sources and suggests economic and efficient coordinated control methods. Simulation with PSCAD proves effectiveness.

This study was carried out to improve the mechanical strength of polyvinyl alcohol (PVA)/alginate carriers for long-term stability of deammonification process. The post-treatment of PVA/alginate carriers with glutaraldehyde (Gl) under mild conditions was proposed for stronger crosslinking and the utilization for deammonification operation. FTIR spectra showed enhanced crosslinking with increasing Gl concentration (0.2, 0.5, 1.0, and 2.0%), acid catalyst concentration (0, 0.1 and 0.5%), and reaction duration. Among the physical parameters affected by Gl crosslinking, the mechanical strength, as tested by the endurance to internal pressure test, was markedly improved by the enhanced crosslinking. The optimal crosslinking conditions were selected for the deammonification test based on the physical parameters under the mildest possible conditions. The selected carriers were tested for inhibition of deammonification microorganisms under toxic crosslinking conditions. Deammonification activity (DA) showed no clear inhibition in Gl compared with the control. After mild variations due to changing environmental conditions for the deammonification bacteria, the total nitrogen (TN) removal efficiency of all Gl-crosslinked carriers was superior to that of the control after 20 days of operation. Therefore, the pre-treatment of PVA/alginate by Gl can improve the durability of the carrier and the stability of the deammonification process.

Primary aortoenteric fistula (PAEF) is a rare but catastrophic cause of massive gastrointestinal bleeding. Diagnosis of PAEF is difficult to make and is frequently delayed without strong clinical suspicion. Timely surgical intervention is essential for patient's survival. We report on a case of an 86-year-old woman with no history of abdominal surgery, who presented with abdominal pain. Initially, computed tomography scan showed an intra-abdominal abscess, located anterior to the aortic bifurcation. However, she was discharged without treatment because of spontaneous improvement on a follow-up computed tomography scan, which showed a newly developed right common iliac artery aneurysm. One week later, she was readmitted due to recurrent abdominal pain. On the second day of admission, sudden onset of gastrointestinal bleeding occurred for the first time. After several endoscopic examinations, an aortoenteric fistula bleeding site was found in the sigmoid colon, and aortography showed progression of a right common iliac artery aneurysm. We finally concluded that intra-abdominal abscess induced an infected aortic aneurysm and enteric fistula to the sigmoid colon. This case demonstrated an extremely rare type of PAEF to the sigmoid colon caused by an infected abdominal aortic aneurysm, which has rarely been reported.

Recently, DG(Distributed Generation) is rapidly developed around the world. But there are several problems in the grid-connected operation. The paper focuses on the selection of proper transformers to meet the grounding requirements in the distribution networks. Through theory analysis and simulation, optimal selection methods are proposed. Yg/Δ-connection transformer is suitable for small resistance grounding distribution networks while Δ /Yg and Δ / Δ connection transformers are fit for small current neutral grounding networks. The conclusions are useful for the DG-connected power system.