Typical emerging contaminants in sewage treatment plant effluent, and related watersheds in the Pearl River Basin: Ecological risks and source identification.

Emerging contaminants pose a potential risk to aquatic ecosystems in the Pearl River Basin, China, owing to the high population density and active industry. This study investigated samples from eight sewage treatment plants, and five surface water bodies of related watersheds. To screen the risk of emerging contaminants (ECs), and clarify their sources, this study calculated the risk quotient of detected chemical and performed source identification/apportionment using the positive matrix factorization method. In total, 149 organic pollutants were identified. Pharmaceuticals showed significant concentrations in sewage treatment plant samples (120.87 ng/L), compared with surface water samples (1.13 ng/L). The ecological risk assessment identified three chemicals with a heightened risk to aquatic organisms: fipronil sulfide, caffeine, and roxithromycin. Four principal sources of contaminants were identified: pharmaceutical wastewater, domestic sewage, medical effluent, and agricultural runoff. Pharmaceutical wastewater was the primary contributor (60.4 %), to the cumulative EC concentration and to ECs in sewage treatment plant effluent. Agricultural drainage was the main source of ECs in surface water. This study provides a strategy to obtain comprehensive information on the aquatic risks and potential sources of EC species in areas affected by artificial activities, which is of substantial importance to pollutant management and control.

Toll-like Receptor 4 Differentially Modulates Cardiac Function in Response to Chronic Exposure to High-Fat Diet and Pressure Overload.

BACKGROUND/AIM: The impact of myocardial stressors such as high-fat diet (HFD) and pressure overload has been extensively studied. Toll-like receptor 4 (TLR4) deficiency has been suggested to have a protective role in response to these stressors, although some conflicting data exist. Furthermore, there is limited information about the role of TLR4 on cardiac remodeling in response to long-term exposure to stressors. This study aims to investigate the effects of TLR4 deficiency on cardiac histology and physiology in response to chronic stressors. METHODS: TLR4-deficient (TLR4-/-) and wild-type (WT) mice were subjected to either HFD or a normal diet (ND) for 28 weeks. Another group underwent abdominal aortic constriction (AAC) or a sham procedure and was monitored for 12 weeks. Inflammatory markers, histology, and echocardiography were used to assess the effects of these interventions. RESULTS: TLR4-/- mice exhibited reduced cardiac hypertrophy and fibrosis after long-term HFD exposure compared to ND without affecting cardiac function. On the other hand, TLR4 deficiency worsened cardiac function in response to AAC, leading to decreased ejection fraction (EF%) and increased end-systolic volume (ESV). CONCLUSIONS: TLR4 deficiency provided protection against HFD-induced myocardial inflammation but impaired hemodynamic cardiac function under pressure overload conditions. These findings highlight the crucial role of TLR4 and its downstream signaling pathway in maintaining cardiac output during physiologic cardiac hypertrophy in response to pressure overload.

A new large area MCP-PMT for high energy detection.

20-inch Large area photomultiplier tube based on microchannel plate (MCP-PMT) is newly developed in China. It is widely used in high energy detection experiments such as Jiangmen Underground Neutrino Observatory (JUNO), China JinPing underground Laboratory (CJPL) and Large High Altitude Air Shower Observatory (LHAASO). To overcome the poor time performance of the existing MCP-PMT, a new design of large area MCP-PMT is proposed in this paper. Three-dimensional models are developed in CST Studio Suite to validate its feasibility. Effects of the size and bias voltage of the focusing electrodes and MCP configuration on the collection efficiency (CE) and time performance are studied in detail using the finite integral technique and Monte Carlo method. Based on the simulation results, the optimized operating and geometry parameters are chosen. Results show that the mean ratio of photoelectrons landing on the MCP active area is 97.5%. The acceptance fraction of the impinging photoelectrons is close to 100% due to the emission of multiple secondary electrons when hitting the MCP top surface. The mean transit time spread (TTS) of the photoelectrons from the photocathode is 1.48 ns.

Rare earth metals detection and recognition based on laser induced breakdown spectroscopy and machine learning.

The rapid detection and identification of the electronic waste (e-waste) containing rare earth (RE) elements is of great significance for the recycling of RE elements. However, the analysis of these materials is extremely challenging due to extreme similarities in appearance or chemical composition. In this research, a new system based on laser induced breakdown spectroscopy (LIBS) and machine learning algorithms is developed for identifying and classifying e-waste of rare-earth phosphors (REPs). Three different kinds of phosphors are selected and the spectra is monitored using this new developed system. The analysis of phosphor spectra shows that there are Gd, Yd, and Y RE element spectra in the phosphor. The results also verify that LIBS could be used to detect RE elements. An unsupervised learning method, principal component analysis (PCA), is used to distinguish the three phosphors and training data set is stored for further identification. Additionally, a supervised learning method, backpropagation artificial neural network (BP-ANN) algorithm is used to establish a neural network model to identify phosphors. The result show that the final phosphor recognition rate reaches 99.9%. The innovative system based on LIBS and machine learning (ML) has the potential to improve rapid in situ detection of RE elements for the classification of e-waste.

miR-135a Regulates Atrial Fibrillation by Targeting Smad3.

Background: Atrial fibrillation (AF) is the most common arrhythmia in clinical. Atrial fibrosis is a hallmark feature of atrial structural remodeling in AF, which is regulated by the TGF-ß1/Smad3 pathway. Recent studies have implicated that miRNAs are involved in the process of AF. However, the regulatory mechanisms of miRNAs remain largely unknown. This study is aimed at investigating the function and regulatory network of miR-135a in AF. Methods: In vivo, the plasma was collected from patients with AF and non-AF subjects. Adult SD rats were induced by acetylcholine (ACh) (66 µg/ml)-CaCl2 (10 mg/ml) to establish an AF rat model. In vitro, atrial fibroblasts (AFs), isolated from adult SD rats, were treated with high-frequency electrical stimulation (HES) (12 h) and hypoxia (24 h) to mimic the AF and atrial fibrosis, respectively. miR-135a expression was detected through quantitative real-time polymerase chain reaction (qRT-PCR). The association between miR-135a and Smad3 was speculated by the TargetScan database and confirmed by the luciferase reporter assay. Fibrosis-related genes, Smad3, and TRPM7 were all assessed. Results: The expression of miR-135a was markedly decreased in the plasma of AF patients and AF rats, which was consistent with that in HES-treated and hypoxia-treated AFs. Smad3 was identified as a target of miR-135a. the downregulation of miR-135a was associated with the enhancement of Smad3/TRPM7 expressions in AFs. Additionally, the knockdown of Smad3 significantly reduced the expression of TRPM7 and further inhibited atrial fibrosis. Conclusions: Our study demonstrates that miR-135a regulates AF via Smad3/TRPM7, which is a potential therapeutic target for AF.

Improved YOLOv5 infrared tank target detection method under ground background.

The detection precision of infrared seeker directly affects the guidance precision of infrared guidance system. To solve the problem of low target detection accuracy caused by the change of imaging scale, complex ground background and inconspicuous infrared target characteristics when infrared image seeker detects ground tank targets. In this paper, a You Only Look Once, Transform Head Squeeze-and-Excitation (YOLOv5s-THSE) model is proposed based on the YOLOv5s model. A multi-head attention mechanism is added to the backbone and neck of the network, and deeper target features are extracted using the multi-head attention mechanism. The Cross Stage Partial, Squeeze-and-Exclusion module is added to the neck of the network to suppress the complex background and make the model pay more attention to the target. A small object detection head is introduced into the head of the network, and the CIoU loss function is used in the model to improve the detection accuracy of small objects and obtain more stable training regression. Through these several improvement measures, the background of the infrared target is suppressed, and the detection ability of infrared tank targets is improved. Experiments on infrared tank target datasets show that our proposed model can effectively improve the detection performance of infrared tank targets under ground background compared with existing methods, such as YOLOv5s, YOLOv5s + SE, and YOLOV 5 s + Convective Block Attention Module.

Gastric bypass alters diurnal feeding behavior and reprograms the hepatic clock to regulate endogenous glucose flux.

The molecular clock machinery regulates several homeostatic rhythms, including glucose metabolism. We previously demonstrated that Roux-en-Y gastric bypass (RYGB) has a weight-independent effect on glucose homeostasis and transiently reduces food intake. In this study we investigate the effects of RYGB on diurnal eating behavior as well as on the molecular clock and this clock's requirement for the metabolic effects of this bariatric procedure in obese mice. We find that RYGB reversed the high-fat diet-induced disruption in diurnal eating pattern during the early postsurgery phase of food reduction. Dark-cycle pair-feeding experiments improved glucose tolerance to the level of bypass-operated animals during the physiologic fasting phase (Zeitgeber time 2, ZT2) but not the feeding phase (ZT14). Using a clock gene reporter mouse model (mPer2Luc), we reveal that RYGB induced a liver-specific phase shift in peripheral clock oscillation with no changes to the central clock activity within the suprachiasmatic nucleus. In addition, we show that weight loss effects were attenuated in obese ClockΔ19 mutant mice after RYGB that also failed to improve glucose metabolism after surgery, specifically hepatic glucose production. We conclude that RYGB reprograms the peripheral clock within the liver early after surgery to alter diurnal eating behavior and regulate hepatic glucose flux.

Efficiency and mechanism of ozonated microbubbles for enhancing the removal of algae and algae-derived organic matter.

The effective control of eutrophication caused by algae blooms is still the focus of global attention. The traditional dissolved air floatation process for algae removal has a low adhesion efficiency between bubbles and algal cells and a low removal efficiency of organic pollutants. Aiming to address these defects, this study set up an ozone microbubble-enhanced air flotation experiment to explore the removal trends of algal cells and algal organic matter (AOM) pollution. In contrast to traditional air flotation, this approach targets the removal of various forms of AOM after algal cell damage. The highest removal rates of algal cells, extracellular microcystin (Mc), intracellular Mc-lr and total Mc-lr were 96.6%, 60.1%, 95.2% and 93.7%, respectively. Compared with the traditional process, the absorption rate and utilization rate of ozone were increased by 41.9% and 46.2%, respectively. The removal effect of AOM was also greatly improved, and ozone microbubbles enhanced the removal of aromatic protein-like substances and high-molecular-weight fulvic acid, humic acid and humic substances. The advantageous synergistic effect of ozone and microbubbles on algae removal was analyzed by exploring the enhanced air flotation removal mechanism of ozone microbubbles' enhanced air floatation removal. Good vacuole adhesion and strong oxidation caused by ozone microbubbles jointly guaranteed a good removal rate of AOM. The enhanced air flotation process with ozone microbubbles has high feasibility and a good effect, can effectively remove algal cells and algal pollutants, and has great potential in algal removal and control of water eutrophication.

Synergistic improvement of nitrogen and phosphorus removal in constructed wetlands by the addition of solid iron substrates and ferrous irons.

Sanjiang Plain is intensively used for rice production, and ditch drainage diffuse pollution prevention is crucial. Groundwater, rich in Fe ions, is the main source of irrigation water in this region. In this study, pyrite and zero-valent iron (ZVI) (sponge iron and iron scraps) were used as substrates to identify the synergistic influence of exogenous Fe2+ addition and solid iron substrates on pollutant removal in constructed wetlands. Based on the results, iron substrates hardly improved the ammonia removal, mainly because of the physical structure and oxidation activity. At a hydraulic retention time longer than 8 h, the pollution removal efficiency in the zero-valent iron (ZVI) substrate treatment increased significantly, and the removal of nitrate (NO3 --N) and total phosphorus (TP) in the iron scrap substrate treatment reached about 60% and 70%, respectively. The high-throughput sequencing results showed a significant increase in the abundance of microorganisms involved in denitrification and phosphate accumulation in biofilms on ZVI substrates. The highest diversities of such microorganisms in biofilms on iron scraps were found for denitrifying bacteria (Pseudomonas), nitrate-reducing Fe (II)-oxidizing bacteria (Acidovorax), and Dechloromonas with autotrophic denitrification and phosphate accumulation, with a 43% cumulative abundance. Dechloromonas dominated in the iron sponge substrate treatment. The highest relative abundance of Acidovorax was found in the mixed iron substrate (pyrite, sponge iron, and iron scraps) treatment. The addition of ZVI substrate significantly improved the removal of NO3 --N and TP and reduced the hydraulic retention time through the continuous release of Fe2+ and the promotion of microbial growth. When designing constructed wetlands for treating paddy field drainage, the appropriate addition of iron scrap substrates is recommended to enhance the pollutant removal efficiency and shock load resistance of CWs.

A large-format streak tube for compressed ultrafast photography.

Streak cameras are powerful imaging instruments for studying ultrafast dynamics with the temporal resolution ranging from picosecond to attosecond. However, the confined detection area limits the information capacity of streak cameras, preventing them from fulfilling their potential in lidar, compressed ultrafast photography, etc. Here, we designed and manufactured a large-format streak tube with a large-size round-aperture gate, a spherical cathode, and a spherical screen, leading to an expanded detection area and a high spatial resolution. The simulation results show that the physical temporal resolution of the streak tube is better than 45 ps and the spatial resolutions are higher than 14 lp/mm in the whole area of 24 × 28 mm2 on the cathode. The experiments demonstrate the streak tube's application potential in weak light imaging benefiting from the imaging magnification of 0.79, a photocathode radiance sensitivity of 37 mA/W, a radiant emitting gain of 11.6 at the wavelength of 500 nm, and a dynamic range higher than 512:1. Most importantly, in the photocathode area of Φ35 mm, the static spatial resolutions at the center and the edge along the slit (R = 16 mm) reach 32 and 28 lp/mm, respectively, and are higher than 10 lp/mm in the whole area of 24 × 28 mm2 on the cathode, allowing for a considerable capacity for spatial information.

Transcriptional regulation mechanism of wheat varieties with different nitrogen use efficiencies in response to nitrogen deficiency stress.

BACKGROUND: As one of the microelements, nitrogen play essential roles in cereal production. Although the use of chemical fertilizers has significantly improved the yield of wheat, it has also caused increasingly adverse environmental pollution. Revealing the molecular mechanism manipulating wheat nitrogen use efficiency (NUE), and cultivating wheat germplasms with high nitrogen use efficiency has become important goals for wheat researchers. In this study, we investigated the physiological and transcriptional differences of three wheat cultivars with different NUE under low nitrogen stress. RESULTS: The results showed that, under low nitrogen conditions, the activities of nitrogen metabolism-related enzymes (GS, NR, GDH), antioxidant enzymes (SOD, POD, CAT) and soluble protein contents of ZM366 (high NUE cultivar) were higher than those of JD8 (low NUE cultivar). The hybrid cultivar of ZM366 and JD8 showed mid-parent or over-parent heterosis. Transcriptome analysis revealed that 'alanine, aspartate and glutamate metabolism', 'terpenoid backbone biosynthesis' and 'vitamin B6 metabolism' pathways play key roles in nitrogen use efficiency in wheat. The significant enhancement of the 'Calvin cycle' and 'photorespiration' in ZM366 contributed to its higher level of carbon metabolism under low nitrogen stress, which is an important attribute differs from the other two varieties. In addition, the activation of ABA signal transduction and biosynthesis pathways also helps to maintain NUE under low- nitrogen conditions. Moreover, bHLH transcription factors were also found to play a positive role in wheat NUE. CONCLUSIONS: In conclusion, these results enriched our knowledge of the mechanism of wheat NUE, and provided a theoretical basis for improving wheat NUE and breeding new cultivars.

Large area MCP-PMT design with good time performance.

A new large area photomultiplier tube based on the microchannel plates (MCP-PMT) with high collection efficiency (CE) and good time performance is proposed in this paper. A novel focusing system with two cylindrical and a conical barrels is designed to generate the accelerating and focusing electric field. A three-dimensional model is developed by CST Studio Suite to validate its feasibility. Finite Integral Technique and Monte Carlo method are combined to simulate the process. Results predict that CE of the novel MCP-PMT is expected to be 100%. TTS of the photoelectrons from the whole photocathode achieves 1.2 ns. Differ from other large area PMTs, it performs well in the geomagnetic field.

Effect of Vitapex Combined with AH-Plus Paste on Inflammation in Middle-Aged and Elderly Patients with Periodontal-Endodontic Disease.

Aims: To investigate the effect of Vitapex combined with AH-plus paste on inflammation in middle-aged and elderly patients with periodontal-endodontic disease. Materials and Methods: A total of 80 teeth of middle-aged and elderly patients with the periodontal-endodontic disease who were treated in our hospital from June 2020 to June 2021 were selected as the research objects and were divided into comparison group and treatment group with 40 teeth each according to different treatment methods. Among them, the comparison group was filled with zinc oxide clove oil paste gutta-percha, and the treatment group was filled with Vitapex combined with AH-plus paste. The changes in apical cross-section sealing performance, periodontal pocket depth (PD), and gingival index (GI) of the two groups before treatment and after 6 months of follow-up were observed and compared, and X-ray analysis was performed. Results: There was no significant difference in the level of periodontal indexes and serum inflammatory indexes between the two groups before treatment (P > 0.05). After treatment, the levels of PD, BI, PLI, and GI in the two groups were significantly lower than before treatment (P < 0.05). The differences in IL-6, IL-10, TNF-α, and IL-1ß after treatment were significant (P < 0.05). There was no significant difference in the root canal area data of each cross-section between the two groups when the root canal was filled with root filling paste at different positions from the apex (P > 0.05). After root canal filling with root canal paste, the cross-sectional area from different parts of the root canal in the treatment group was significantly smaller than comparison group (P < 0.05). After 6 months of treatment, it was found that CEJ-BD and CEJ-AC in the treatment group were significantly lower than those in the comparison group (P < 0.05). Conclusion: Vitapex combined with AH-plus paste filling can effectively treat middle-aged and elderly periodontal-endodontic disease, which provides a certain reference for the clinical treatment of middle-aged and elderly periodontal-endodontic disease.

Optimization design of the large area Dynode-MCP-PMT.

The optimization work of a newly proposed 20-in. photomultiplier tube based on dynode and microchannel plates (Dynode-MCP-PMT) are conducted in this paper. Three-dimensional models are developed in CST STUDIO SUITE to systematically investigate the effects of the size and bias voltage of the two focusing electrodes, dynode and the glass envelop handle based on the Finite Integral Technique and Monte Carlo method. Results predict that the collection efficiency and the transit time spread of the optimized design are substantially improved which are 100% and 3.7 ns.

Cut-off values of neonatal lysosomal storage disease-related enzymes detected by tandem mass spectrometry.

OBJECTIVE: To establish cut-off values of lysosomal storage disease (LSD)-related enzymes by tandem mass spectrometry. METHODS: A total of 26 689 newborns and 7 clinically confirmed LSD children underwent screening for LSDs (glycogen storage disease typeⅡ, Fabry disease, mucopolysaccharidosis type Ⅰ, Krabbe disease, Niemann-Pick disease A/B and Gaucher disease). The activities of LSD-related enzymes were detected by tandem mass spectrometry. The 20% of the median enzyme activity of each batch of acid ß-glucocerebrosidase, acid sphingomyelinase, ß-galactocerebroside, α- L-iduronidase and acid α-glucosidase, and the 30% of the median enzyme activity of α-galactosidase were taken as cut-off values of corresponding enzymes. The genetic diagnosis was performed in neonates whose enzyme activity was lower than 70% of the cut-off value. RESULTS: The enzyme activities of 7 clinically confirmed cases were all lower than the cut-off values. Among 26 689 newborns, 142 cases (0.53%) were suspected positive for LSDs, including 25 cases of ß-galactocerebroside deficiency, 1 case of α- L-iduronidase deficiency, 19 cases of α-galactosidase deficiency, and 97 cases of acid α-glucosidase deficiency. Eight infants were genetically diagnosed with LSDs, including 3 cases of glycogen storage disease type Ⅱ, 3 cases of Krabbe disease, and 2 cases of Fabry disease, with a positive predictive value of about 5.6%. Cut-off values ​​of the 6 LSD enzyme activities all showed a downward trend from March to August, and an upward trend from September to December. There was a statistically significant difference in LSD enzyme activity among different months ( P<0.05). CONCLUSION: The established cut-off values of LSD-related enzyme activities detected by tandem mass spectrometry can be used for screening LSDs in neonates, and the enzyme activity would be affected by temperature and humidity.

Establishment of Cutoff Values for Newborn Screening of Six Lysosomal Storage Disorders by Tandem Mass Spectrometry.

Objective: Lysosomal storage disorders (LSDs) are becoming increasingly important in newborn screening, and tandem mass spectrometry (MS/MS) is widely used in newborn screening for LSDs through measurement of enzymatic activities in dried blood spots (DBSs). Overall, the determination of the cutoff value is important in such screening, and different laboratories have different methods of determining this value; most do not use a fixed cutoff value but rather calculate the corresponding batch cutoff value based on each batch of experimental data. In this study, we used MS/MS to screen for LSDs and sought to find an appropriate method to establish the cutoff value for LSD screening. Methods: A total of 38,945 samples from newborn blood tablets collected from various maternity hospitals in six cities in Shandong province, including Jinan, Dezhou, Heze, Linyi, Weifang, and Zibo, were tested using a Waters Xevo TQD tandem mass spectrometer; the experimental data were analyzed with MassLynx V4.1. The laboratory used 30% of the median GLA enzyme activity and 20% of the median ABG, ASM, GALC, IDUA, and GAA enzyme activities in every test as the cutoff values for that batch of experiments. Results: There were 254 suspicious positives in the initial screening test, including one case of Gaucher disease, one of Niemann-Pick disease, 47 of Krabbe disease, four of MPS-I, 21 of Fabry disease, and 180 of Pompe disease. After genetic screening, 11 children were diagnosed, including three with Pompe disease, three with Fabry disease, and five with Krabbe disease. In addition, the enzyme activity cutoff value of this experiment showed seasonal variation, which was initially believed to be related to the ambient temperature, such as the effect of ambient temperature on the human body or the temperature when the blood tablets dried naturally. Conclusion: Overall, MS/MS can be used in LSD screening, and using different cutoff values in each batch of experiments is feasible. The ambient temperature might be a reason why the enzyme activity cutoff value has seasonal variation. More samples are needed to develop a method of determining cutoff values in laboratories.

Study on the operation performance and floc adhesion mechanism of dissolved air flotation equipment.

As a critical air dissolving system, the performance of air flotation equipment directly determines the adhesion efficiency and pollutant removal efficiency of air flotation processes. The factors affecting the performance of air flotation equipment and the relationships between equipment performance and pollution removal efficiency were studied. The results show that when the dissolved gas pressure was 0.4 MPa and the air intake rate was 24 mL/min, the dissolved gas efficiency of the equipment reached its highest value of 55%, the average particle size of bubbles was maintained at 24 µm, and the dissolved oxygen (DO) content significantly increased. When the dissolved gas pressure was 0.4 MPa, the air intake rate was 24 mL/min, and the coagulant dose was 6 mg/L; the removal rates for turbidity, chlorophyll-a, total organic carbon (TOC), and UV absorbance at 254 nm (UV254) reached 95.76%, 96.41%, 34.21%, and 65.96%, respectively. The degree of pollutant removal was positively correlated with changes to the equipment performance parameters. Microbubbles (MBs) showed good removal of high-molecular weight, strongly hydrophobic organic matter and showed some removal of the trihalomethane formation potential (THMFP) of the water. The removal mechanism mainly depended on the hydrophobic interactions of the MBs with algae and organic matter. The flocs and MBs collided and adhered to form air-entrained flocs. The separation of air-entrained flocs depended on the relationship between the surface load and the rising velocity. The surface load has to be lower than the rising velocity of the minimum air-entrained flocs to ensure good effluent outcomes.

Establishment of Reference Intervals for Thyroid-Associated Hormones Using refineR Algorithm in Chinese Population at High-Altitude Areas.

Objectives: Diagnosis of thyroid disease among individuals dwelling at high altitude remains a challenge. Reference intervals (RIs) for thyroid-associated hormones among Tibetans living at various high altitudes were established to improve diagnosis. Methods: One thousand two hundred eighty-one subjects were randomly recruited from Nyingchi, Shigatse/Lhasa, and Ali of Tibet. Thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were measured by the Cobas e601 electrochemiluminescence analyzer. We used multiple linear regression and variance component analysis to assess the effect of sex, age, and altitude on hormones. RIs were established by refineR algorithm and compared with those provided by the manufacturer. Results: Serum TSH was significantly lower in males than in females, while FT3 and FT4 were higher in males. Both FT3 and FT4 decreased with increasing age. FT3 increased with altitude, while TSH and FT4 were less influenced by altitude. The RI for TSH was 0.764-5.784 µIU/ml, while for FT4, the RIs were 12.36-19.38 pmol/L in females and 14.84-20.18 pmol/L in males. The RIs for FT3 at Nyingchi, Shigatse/Lhasa, and Ali in females were 4.09-4.98, 4.31-5.45, and 4.82-5.58 pmol/L, while in males, the values were 4.82-5.41, 4.88-5.95, and 5.26-6.06 pmol/L, respectively. The obtained RIs for TSH and FT4 were generally higher, while that for FT3 was narrower than the RIs provided by Cobas. Conclusions: Specific RIs were established for thyroid-associated hormones among Tibetans, which were significantly different from those provided by the manufacturer.

Effectiveness of Exogenous Fe2+ on Nutrient Removal in Gravel-Based Constructed Wetlands.

A group of microcosm-scale unplanted constructed wetlands (CWs) were established to evaluate the effectiveness of exogenous Fe2+ addition on ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), and total phosphorus (TP) removal. The addition of Fe2+ concentrations were 5 mg/L (CW-Fe5), 10 mg/L (CW-Fe10), 20 mg/L (CW-Fe20), 30 mg/L (CW-Fe30), and 0 mg/L (CW-CK). The microbial community in CWs was also analyzed to reveal the enhancement mechanism of pollutant removal. The results showed that the addition of Fe2+ could significantly (p < 0.05) reduce the NO3--N concentration in the CWs. When 10 mg/L Fe2+ was added and the hydraulic retention time (HRT) was 8 h, the highest removal rate of NO3--N was 88.66%. For NH4+-N, when the HRT was 8-24 h, the removal rate of CW-Fe5 was the highest (35.23% at 8 h and 59.24% at 24 h). When the HRT was 48-72 h, the removal rate of NH4+-N in CWs with 10 mg/L Fe2+ addition was the highest (85.19% at 48 h and 88.66% and 72 h). The removal rate of TP in all CWs was higher than 57.06%, compared with CW-CK, it increased 0.63-31.62% in CWs with Fe2+ addition; the final effluent TP concentration in CW-Fe5 (0.13 mg/L) and CW-Fe10 (0.16 mg/L) met the class III water standards in Surface Water Environmental Quality Standards of China (GB3838-2002). Microbical diversity indexes, including Shannon and Chao1, were significantly lower (p < 0.05) in Fe2+ amended treatment than that in CW-CK treatment. Furthermore, phylum Firmicutes, family Carnobacteriaceae, and genus Trichococcus in Fe2+ amended treatments was significantly (p < 0.05) higher than that in CW-CK treatment. Fe3+ reducing bacteria, such as Trichococcus genus, belonging to the Carnobacteriaceae in family-level, and Lactobacillales order affiliated to Firmicutes in the phylum-level, can reduce the oxidized Fe3+ to Fe2+ and continue to provide electrons for nitrate. It is recommended to consider adding an appropriate amount of iron into the water to strengthen its purifying capacity effect for constructed artificial wetlands in the future.