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1.
Anal Chem ; 2024 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-39096242

RESUMEN

Small interfering RNA (siRNA) highlights the immense therapeutic potential for cancer treatment. The major challenge in siRNA therapy is the effective RNA nanodrug delivery system, which is facilitated by the ligand and the carrier. In this study, we analyzed the binding specificity of linear RGD and circular RGD to αVß3 integrins by mapping the morphology using super-resolution direct stochastic optical reconstruction microscopy. Meanwhile, the binding dynamics was investigated using single-molecule force spectroscopy. Then, the effects of the ligand and carrier on RNA nanodrug cell entry dynamic parameters were evaluated at the single particle level by the force tracing technique. Furthermore, the delivery efficiency of RNA nanodrugs was assessed using AFM-based nanoindentation at the single cell level. This report will provide valuable insights for rational design strategies aiming to achieve improved efficiency for nanodrug delivery systems.

2.
Nutr Res ; 128: 94-104, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-39096661

RESUMEN

Animal studies showed a detrimental effect of dietary branched chain amino acids (BCAAs) on metabolic health, while epidemiological evidence on dietary BCAAs and obesity is limited and inconclusive. We hypothesized that high dietary and circulating BCAAs are unfavorably associated with obesity in community-dwelling adults. We evaluated the 1-year longitudinal associations of dietary BCAA intake and circulating BCAAs with body fat measures. Body weight, height, and circumferences of the waist (WC) and hip (HC) were measured at baseline and again after 1-year. Body composition and liver fat [indicated by controlled attenuation parameter (CAP)] were also assessed after 1-year. Serum BCAA concentrations at baseline were quantified by liquid chromatography mass spectrometry. Diet was collected using 4 quarterly 3-day recalls during the 1-year. The correlation coefficients between dietary and serum BCAAs were 0.12 (P = .035) for total dietary BCAAs, and ranged from -0.02 (soy foods, P = .749) to 0.18 (poultry, P = .001). Total dietary BCAA intake was associated with increase in body weight (ß = 0.044, P = .022) and body mass index (BMI, ß = 0.047, P = .043). BCAAs from animal foods were associated with increase in HC, while BCAAs from soy foods were associated with weight gain and higher CAP (all P < .05). Serum BCAAs were associated with higher WC, HC, BMI, body fat mass, visceral fat level, and CAP (all P < .05). These results support that dietary and circulating BCAAs are positively associated with the risk of obesity. More cohort studies with validated dietary assessment tools and long-term follow-up among diverse populations are needed to confirm our findings.

3.
Food Funct ; 2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39056149

RESUMEN

Aims: Epidemiological studies that use dietary biomarkers to investigate the association between whole grain intake and the risk of obesity are sparse. We assessed the association between urinary alkylresorcinol metabolites including 3-(3,5-dihydroxyphenyl)-1-propanoic acid (DHPPA) and 3,5-dihydroxybenzoic acid (DHBA), biomarkers of whole grain wheat and rye intake, and body fat measures. Methods: We measured urinary excretion of DHPPA and DHBA, body weight, height, and circumferences of the waist and hip at the baseline and again after 1-year in a representative sample of 306 community-dwelling adults in Huoshan, China. We also measured liver fat accumulation [indicated by the controlled attenuation parameter (CAP)] and other body composition after 1 year. Multivariate-adjusted linear models and linear mixed-effects models were used to analyze single measurement and repeated measurements, respectively. Results: Each 1 µg g-1 creatinine increase in urinary DHPPA levels was associated with 0.21%, 0.23%, 3.64%, and 4.80% decrease in body weight, body mass index (BMI), body fat mass (BFM) and visceral fat level (VFL), respectively (all P < 0.05). Higher DHBA levels were inversely associated with CAP (percentage difference per 1 µg g-1 creatinine increment: -1.98%, P < 0.05). Higher total urinary alkylresorcinol metabolite (DHPPA + DHBA) levels were associated with lower body weight, BMI, BFM, VFL, and CAP, with the percentage differences per 1 µg g-1 creatinine increment of -0.27%, -0.27%, -3.79%, -5.12%, and -2.24%, respectively (all P < 0.05). Conclusions: Our findings suggest that the intake of whole grain wheat and rye, reflected by urinary DHPPA and DHBA, is favorably associated with liver fat and other fat measures.

4.
Adv Sci (Weinh) ; : e2404404, 2024 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-38973215

RESUMEN

Drawing inspiration from the jumping mechanisms of insects (e.g., click beetles), bistable structures can convert slow deformations of soft actuating material into fast jumping motions (i.e., power amplification). However, bistable jumpers often encounter large energy barriers for energy release/re-storage, posing a challenge in achieving multimodal (i.e., height/distance) and continuous jumps at the insect scale (body length under 20 mm). Here, a new offset-buckling bistable design is introduced that features antisymmetric equilibrium states and tunable energy barriers. Leveraging this design, a Boundary Actuation Tunable Energy-barrier (BATE) jumper (body length down to 15 mm) is developed, and transform BATE jumper from height-jump mode (up to 12.7 body lengths) to distance-jump mode (up to 20 body lengths). BATE jumpers can perform agile continuous jumping (within 300 ms for energy release/re-storage times) and real-time status detection is further demonstrated. This insect-level performance of the proposed BATE jumper showcases its potential toward future applications in exploration, search, and rescue.

5.
Sci Adv ; 10(30): eadp0348, 2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39047112

RESUMEN

Replicating human somatosensory networks in robots is crucial for dexterous manipulation, ensuring the appropriate grasping force for objects of varying softness and textures. Despite advances in artificial haptic sensing for object recognition, accurately quantifying haptic perceptions to discern softness and texture remains challenging. Here, we report a methodology that uses a bimodal haptic sensor to capture multidimensional static and dynamic stimuli, allowing for the simultaneous quantification of softness and texture features. This method demonstrates synergistic measurements of elastic and frictional coefficients, thereby providing a universal strategy for acquiring the adaptive gripping force necessary for scarless, antislippage interaction with delicate objects. Equipped with this sensor, a robotic manipulator identifies porcine mucosal features with 98.44% accuracy and stably grasps visually indistinguishable mature white strawberries, enabling reliable tissue palpation and intelligent picking. The design concept and comprehensive guidelines presented would provide insights into haptic sensor development, promising benefits for robotics.


Asunto(s)
Robótica , Animales , Porcinos , Humanos , Fuerza de la Mano/fisiología , Tacto
6.
ACS Omega ; 9(25): 27104-27112, 2024 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-38947830

RESUMEN

The combustion of lithium-ion batteries is characterized by fast ignition, prolonged duration, high combustion temperature, release of significant energy, and generation of a large number of toxic gases. Fine water mist has characteristics such as a high fire extinguishing efficiency and environmental friendliness. In order to thoroughly investigate the temperature control effect of fine water mist on lithium-ion battery fires. This study employs numerical simulation methods, utilizing PyroSim software to simulate the fire process in lithium-ion battery energy storage compartments. First, we focus on the variation patterns of flame, changes in combustion temperature, and heat release rate over time at environmental temperatures of 10, 25, and 35 °C. Subsequently, the suppression of flame, reduction in temperature, and changes in heat release rate are simulated for water mist in lithium-ion battery fires. The simulation results indicate that the environmental temperature has a considerable impact on the flame but a lesser effect on the heat release rate. Fine water mist effectively impedes the spread of thermal runaway between internal battery core cells, leading to a reduction in the flame size and a significant decrease in the maximum temperature and heat release rate. The numerical simulation results can provide scientific guidance for the prevention and control of fires in lithium-ion battery energy storage compartments.

7.
Adv Sci (Weinh) ; : e2402796, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38961646

RESUMEN

The buried interface between the electron transport layer (ETL) and the perovskite layer plays a crucial role in enhancing the power conversion efficiency (PCE) and stability of n-i-p type perovskite solar cells (PSCs). In this study, the interface between the chemical bath deposited (CBD) titanium oxide (TiO2) ETL and the perovskite layer using multi-functional potassium trifluoromethyl sulfonate (SK) is modified. Structural and elemental analyses reveal that the trifluoromethyl sulfonate serves as a crosslinker between the TiO2 and the perovskite layer, thus improving the adhesion of the perovskite to the TiO2 ETL through strong bonding of the ─CF3 and ─SO3 - terminal groups. Furthermore, the multi-functional modifiers reduced interface defects and suppressed carrier recombination in the PSCs. Consequently, devices with a champion PCE of 25.22% and a fill factor (FF) close to 85% is achieved, marking the highest PCE and FF observed for PSCs based on CBD TiO2. The unencapsulated device maintained 81.3% of its initial PCE after operating for 1000 h.

8.
J Nutr ; 2024 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-39033820

RESUMEN

BACKGROUND: Many studies have investigated the intake of dietary isoflavones in relation to obesity risk, while the association using objective biomarkers of isoflavones, particularly equol (a gut-derived metabolite of daidzein with greater bioavailability than other isoflavones) has been less studied. In addition, the associations between equol and gut microbiota profile at population level remain to be fully characterized. OBJECTIVE: We aimed to identify equol-predicting microbial species and to investigate the associations of equol-predicting microbial species and urinary excretion of isoflavones including glycitein, genistein, daidzein, and equol with diverse obesity markers in free living-individuals. METHODS: In this 1-year longitudinal study of 754 community-dwelling adults, urinary isoflavones, fecal microbiota, height, weight, and circumferences of waist and hip were measured at baseline and again after 1-year. Liver fat [indicated by controlled attenuation parameter (CAP)] and other body composition were also measured after 1-year. Linear models and linear mixed-effects models were used to analyze the associations for single measure and repeated measures, respectively. RESULTS: Among 305 participants (median age: 50 y, IQR: 37-59 y) including 138 men and 167 women, higher urinary excretion of equol was associated with lower CAP (ß = -0.013, P < 0.001) and body fat mass (ß= -0.014, P = 0.046). No association was found between any other urinary isoflavones and obesity markers (all P>0.05). We identified 21 bacterial genera whose relative abundance were positively associated with urinary equol concentrations (all Pfalsediscovery rate < 0.05), and constructed an equol-predicting microbial score to reflect the overall equol-producing potential of host gut microbiota. This score was inversely associated with CAP (ß = -0.040, P = 0.011). CONCLUSIONS: High urinary equol concentrations and equol-predicting microbial species could be favorably associated with liver fat and other obesity markers.

9.
Chemosphere ; 362: 142557, 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38852632

RESUMEN

Agglomeration and passivation restrict the using zero-valent iron nanoparticles (nZVI). Enhancing the reactivity of nZVI is often accomplished by sulfurization. In this work, nZVI was sulfurized using SRB to produce biosulfurized nano zero-valent iron (BP-S-nZVI), which was then utilized as a catalyst to investigating its performance in an advanced oxidation process based on activated peroxomonosulfate (PMS). When the S/Fe was 0.05, 0.4 g/L of catalyst and 0.5 mM PMS were added to a 20 mg/L ciprofloxacin solution. In 120 min, a 90.4% clearance rate was reached. When the initial pH of the solution was within the range of 3-11, all exhibited acceptable degradation performance and were minimally affected by co-existing anions. In this activation system, hydroxyl, superoxide and sulfate radicals (•OH, O2•- and SO4•-, respectively) have been proven to be the main active species. Seven intermediates in the degradation process of CIP were identified by LC-MS analysis and two possible degradation pathways were proposed. In addition, the degradation rate of CIP was still able to reach 87.0% after five cycles, and the removal rate remained unchanged in the CIP solution with actual water samples as background. This study demonstrated that BP-S-nZVI as a catalyst for the activation of PMS for CIP degradation can still show good reactivity, which provides more possibilities for the practical application of BP-S-nZVI in the degradation of pollutants.

12.
Food Funct ; 15(14): 7305-7313, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-38874113

RESUMEN

Aims: Plant-derived lignans may protect against obesity, while their bioactivity needs gut microbial conversion to enterolignans. We used repeated measures to identify enterolignan-predicting microbial species and investigate whether enterolignans and enterolignan-predicting microbial species are associated with obesity. Methods: Urinary enterolignans, fecal microbiota, body weight, height, and circumferences of the waist (WC) and hips (HC) were repeatedly measured at the baseline and after 1 year in 305 community-dwelling adults in Huoshan, China. Body composition and liver fat [indicated by the controlled attenuation parameter (CAP)] were measured after 1 year. Multivariate-adjusted linear models and linear mixed-effects models were used to analyze single and repeated measurements, respectively. Results: Enterolactone and enterodiol levels were both inversely associated with the waist-to-hip ratio, body fat mass (BFM), visceral fat level (VFL), and liver fat accumulation (all P < 0.05). Enterolactone levels were also associated with lower WC (ß = -0.0035 and P = 0.013) and HC (ß = -0.0028 and P = 0.044). We identified multiple bacterial genera whose relative abundance was positively associated with the levels of enterolactone (26 genera) and enterodiol (22 genera, all P false discovery rate < 0.05), and constructed the enterolactone-predicting microbial score and enterodiol-predicting microbial score to reflect the overall enterolignan-producing potential of the host gut microbiota. Both these scores were associated with lower body weight and CAP (all P < 0.05). The enterolactone-predicting microbial score was also inversely associated with the BFM (ß = -0.1128 and P = 0.027) and VFL (ß = -0.1265 and P = 0.044). Conclusion: Our findings support that modulating the host gut microbiome could be a potential strategy to prevent obesity by enhancing the production of enterolignans.


Asunto(s)
Microbioma Gastrointestinal , Lignanos , Obesidad , Humanos , Lignanos/orina , Masculino , Femenino , Adulto , Persona de Mediana Edad , Obesidad/microbiología , Obesidad/metabolismo , Obesidad/orina , China , Bacterias/clasificación , Bacterias/metabolismo , Bacterias/aislamiento & purificación , Heces/microbiología , Biomarcadores/orina , 4-Butirolactona/análogos & derivados , 4-Butirolactona/orina , 4-Butirolactona/metabolismo , Hígado/metabolismo
13.
Adv Mater ; : e2406682, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38837816

RESUMEN

The utilization of rare earth elements to regulate the interaction between catalysts and oxygen-containing species holds promising prospects in the field of oxygen electrocatalysis. Through structural engineering and adsorption regulation, it is possible to achieve high-performance catalytic sites with a broken activity-stability tradeoff. Herein, this work fabricates a hierarchical CeO2/NiCo hydroxide for electrocatalytic oxygen evolution reaction (OER). This material exhibits superior overpotentials and enhanced stability. Multiple potential-dependent experiments reveal that CeO2 promotes oxygen-species exchange, especially OH- ions, between catalyst and environment, thereby optimizing the redox transformation of hydroxide and the adsorption of oxygen-containing intermediates during OER. This is attributed to the reduction in the adsorption energy barrier of Ni to *OH facilitated by CeO2, particularly the near-interfacial Ni sites. The less-damaging adsorbate evolution mechanism and the CeO2 hierarchical shell significantly enhance the structural robustness, leading to exceptional stability. Additionally, the observed "self-healing" phenomenon provides further substantiation for the accelerated oxygen exchange. This work provides a neat strategy for the synthesis of ceria-based complex hollow electrocatalysts, as well as an in-depth insight into the co-catalytic role of CeO2 in terms of oxygen transfer.

14.
J Am Heart Assoc ; 13(13): e034126, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38934874

RESUMEN

BACKGROUND: The association between soy isoflavones intake and cardiometabolic health remains inconclusive. We investigated the associations of urinary biomarkers of isoflavones including daidzein, glycitein, genistein, equol (a gut microbial metabolite of daidzein), and equol-predicting microbial species with cardiometabolic risk markers. METHODS AND RESULTS: In a 1-year study of 305 Chinese community-dwelling adults aged ≥18 years, urinary isoflavones, fecal microbiota, blood pressure, blood glucose and lipids, and anthropometric data were measured twice, 1 year apart. Brachial-ankle pulse wave velocity was also measured after 1 year. A linear mixed-effects model was used to analyze repeated measurements. Logistic regression was used to calculate the adjusted odds ratio (aOR) and 95% CI for the associations for arterial stiffness. Each 1 µg/g creatinine increase in urinary equol concentrations was associated with 1.47%, 0.96%, and 3.32% decrease in triglycerides, plasma atherogenic index, and metabolic syndrome score, respectively (all P<0.05), and 0.61% increase in high-density lipoprotein cholesterol (P=0.025). Urinary equol was also associated with lower risk of arterial stiffness (aOR, 0.28 [95% CI, 0.09-0.90]; Ptrend=0.036). We identified 21 bacterial genera whose relative abundance was positively associated with urinary equol (false discovery rate-corrected P<0.05) and constructed a microbial species score to reflect the overall equol-predicting capacity. This score (per 1-point increase) was inversely associated with triglycerides (percentage difference=-1.48%), plasma atherogenic index (percentage difference=-0.85%), and the risk of arterial stiffness (aOR, 0.27 [95% CI, 0.08-0.88]; all P<0.05). CONCLUSIONS: Our findings suggest that urinary equol and equol-predicting microbial species may improve cardiometabolic risk parameters in Chinese adults.


Asunto(s)
Biomarcadores , Factores de Riesgo Cardiometabólico , Equol , Microbioma Gastrointestinal , Rigidez Vascular , Humanos , Equol/orina , Masculino , Femenino , Persona de Mediana Edad , Biomarcadores/orina , Biomarcadores/sangre , China/epidemiología , Adulto , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/microbiología , Medición de Riesgo , Isoflavonas/orina , Heces/microbiología , Pueblos del Este de Asia
15.
Eur J Nutr ; 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38809324

RESUMEN

PURPOSE: To investigate the associations between dietary/serum branched-chain amino acids (BCAAs) and cardiometabolic risk markers. METHODS: In a cohort of 2791 participants, diet and cardiometabolic risk markers were measured twice at baseline in overall participants and after 1-year in a subset of 423 participants. We assessed serum BCAAs at baseline and arterial stiffness after 1-year. The cross-sectional associations between dietary/serum BCAAs and cardiometabolic risk markers were analyzed using baseline measurements by linear regression, while the 1-year longitudinal association were analyzed using repeated measurements by linear mixed-effects regression. RESULTS: Higher BCAA intake from poultry was associated with lower triglycerides (ß=-0.028, P = 0.027) and higher high-density lipoprotein cholesterol (HDL-C, ß = 0.013, P = 0.006), while BCAAs in red and processed meat or fish were inversely associated with low-density lipoprotein cholesterol (ß = 0.025, P = 0.001) and total cholesterol (ß = 0.012, P = 0.033), respectively. BCAAs in whole grains and nuts were associated with higher HDL-C (ß = 0.011, P = 0.016), and lower TG (ß=-0.021, P = 0.041) and diastolic blood pressure (ß=-0.003, P = 0.027). Also, BCAAs from soy or vegetables and fruits were inversely associated with arterial stiffness (ß=-0.018, P = 0.047) and systolic blood pressure (ß=-0.011, P = 0.003), respectively. However, BCAAs in refined grains were positively associated with triglycerides (ß = 0.037, P = 0.014). Total serum BCAAs were unfavorably associated with multiple cardiometabolic risk markers (all P < 0.05). CONCLUSION: Dietary BCAAs in poultry, whole grains and nuts, soy, and vegetables and fruits may be favorably, while BCAAs in red and processed meat, fish, and refined grains were unfavorably associated with cardiometabolic health. Serum BCAAs showed a detrimental association with cardiometabolic risk markers.

16.
World Neurosurg ; 188: e326-e333, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38796152

RESUMEN

OBJECTIVE: This study analyzed and explored the relationship between isthmic spondylolisthesis and disc degeneration by comparing the degree of disc degeneration in patients with isthmic spondylolisthesis, lumbar disc herniation, and asymptomatic healthy individuals. METHODS: This study included a total of 138 cases, consisting of L5-S1 single segment lesion patients and a normal lumbar spine population. The cases were divided into 3 groups based on the type of disease: fifty eight cases in the isthmic spondylolisthesis (IS) group, 50 cases in the lumbar disc herniation (LDH) group, and 30 cases in the normal lumbar vertebrae (NLV) group. RESULTS: The research findings indicate that the proportion of intervertebral disc degeneration in the LDH group is significantly higher than that in the IS group and NLV group (65.3% vs. 33.3% vs. 25.8%, P < 0.05). The Pfirrmann grades of lumbar intervertebral discs (L1-L4) in the LDH group are significantly higher than those in the IS group and NLV group (P < 0.05), and the intervertebral height index (IHI) (L1-L4) of lumbar vertebrae in the LDH group is significantly lower than that in the IS group and NLV group (P < 0.05). CONCLUSIONS: The results showed that the degree of intervertebral disc degeneration in patients with isthmic spondylolisthesis was lighter than that in patients with LDH, and even similar to that in healthy individuals. The occurrence of IS may have slowed down the degeneration of nonaffected segment intervertebral discs through certain factors.


Asunto(s)
Degeneración del Disco Intervertebral , Desplazamiento del Disco Intervertebral , Vértebras Lumbares , Espondilolistesis , Humanos , Espondilolistesis/diagnóstico por imagen , Masculino , Femenino , Vértebras Lumbares/diagnóstico por imagen , Persona de Mediana Edad , Adulto , Degeneración del Disco Intervertebral/diagnóstico por imagen , Desplazamiento del Disco Intervertebral/diagnóstico por imagen , Disco Intervertebral/diagnóstico por imagen , Disco Intervertebral/patología , Anciano
17.
ACS Omega ; 9(18): 19911-19922, 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38737087

RESUMEN

In this study, an existing ternary membrane system based on nonsolvent-induced phase separation (NIPS) with a phase-field model was optimized. To study and analyze the effects of different additives on the formation of the skin layer and the effects of the three solvents on membrane characterization under the same conditions, two-dimensional simulations of the relevant parameters of a poly(vinylidene fluoride) (PVDF) membrane system were performed. The specific application of quaternary substances in ternary membrane systems was elaborated by determining the cohesive energy density between the additives and solvents, followed by the interaction parameters χ under the joint effect of the two. The results showed that the PVDF microporous membrane formed a dense surface layer at the mass transfer exchange interface, and with an increase in the poly(ethylene glycol) (PEG) concentration, the phase separation of the skin layer was predominantly transformed from liquid-solid partitioning to liquid-liquid partitioning; the number of membrane pores increased with increasing poly(vinylpyrrolidone) (PVP) concentration. The N,N-dimethylacetamide (DMAc) solvent system had the most stable thermodynamic properties; the dimethyl sulfoxide (DMSO) solvent system had mostly large pores running through the membrane and exhibited a porous structure. Related experiments also validated the model. Therefore, this model can be applied to other PVDF ternary membrane systems to better understand the structural development of microporous PVDF membranes under different conditions.

18.
Cyborg Bionic Syst ; 5: 0103, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38617112

RESUMEN

Soft grippers due to their highly compliant material and self-adaptive structures attract more attention to safe and versatile grasping tasks compared to traditional rigid grippers. However, those flexible characteristics limit the strength and the manipulation capacity of soft grippers. In this paper, we introduce a hybrid-driven gripper design utilizing origami finger structures, to offer adjustable finger stiffness and variable grasping range. This gripper is actuated via pneumatic and cables, which allows the origami structure to be controlled precisely for contraction and extension, thus achieving different finger lengths and stiffness by adjusting the cable lengths and the input pressure. A kinematic model of the origami finger is further developed, enabling precise control of its bending angle for effective grasping of diverse objects and facilitating in-hand manipulation. Our proposed design method enriches the field of soft grippers, offering a simple yet effective approach to achieve safe, powerful, and highly adaptive grasping and in-hand manipulation capabilities.

19.
Chemosphere ; 356: 141883, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38583528

RESUMEN

Comammox Nitrospira and canonical ammonia-oxidizing bacteria (cAOB) generally coexist in activated sludge. In present study, the effect of comammox Nitrospira on N2O production during nitrification of activated sludge was investigated. Comammox Nitrospira and cAOB were separately enriched in two nitrifying reactors, with respective relative abundance of approximately 98% in ammonia oxidizer community. The N2O emission factor (EF) of nitrification in comammox Nitrospira dominated reactor was 0.35%, consistently lower than that (2.2%) in cAOB dominated reactor. When increasing the relative abundance of comammox Nitrospira in ammonia oxidizer community, the N2O EF of nitrification decreased exponentially, which suggested that comammox Nitrospira not only decreased N2O production directly but also might have reduced N2O yield by cAOB. When cAOB dominated the ammonia oxidizer community of sludge, decreasing pH to 6.3, lowering DO to less than 0.5 mg/L, and increasing nitrite concentration enhanced N2O EF dramatically. When comammox Nitrospira became the dominant ammonia oxidizer, however, the N2O EF correlated to nitrite insignificantly and a low DO of 0.2 mg/L and weakly acidic pH (6.3) decreased N2O EF by approximately 70% and 60%, respectively. These results imply that enhancing the relative abundance of comammox Nitrospira in sludge is an effective way to reducing N2O emissions and can also offset the promoting effects of acidic pH, low DO, and high nitrite concentration on N2O production during nitrification.


Asunto(s)
Amoníaco , Bacterias , Nitrificación , Oxidación-Reducción , Aguas del Alcantarillado , Amoníaco/metabolismo , Aguas del Alcantarillado/microbiología , Bacterias/metabolismo , Óxido Nitroso/metabolismo , Nitritos/metabolismo , Reactores Biológicos/microbiología , Eliminación de Residuos Líquidos/métodos
20.
Water Res ; 255: 121491, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38520779

RESUMEN

Pre-capturing organics in municipal wastewater for biogas production, combined with Anammox-based nitrogen removal process, improves the sustainability of sewage treatment. Thus, enhancing nitrogen removal via Anammox in mainstream wastewater treatment becomes very crucial. In present study, a three-stage anoxic/oxic (AO) biofilm process with intermittent aeration was designed to strengthen partial nitrification/denitrification coupling Anammox (PNA/PDA) in treatment of low C/N wastewater, which contained chemical oxygen demand (COD) of 79.8 mg/L and total inorganic nitrogen (TIN) of 58.9 mg/L. With a hydraulic retention time of 8.0 h, the process successfully reduced TIN to 10.6 mg/L, achieving a nitrogen removal efficiency of 83.3 %. The 1st anoxic zone accounted for 32.0 % TIN removal, with 10.3 % by denitrification and 21.7 % by PDA, meanwhile, the 2nd and 3rd anoxic zones contributed 19.4 % and 4.5 % of TIN removal, primarily achieved through PDA (including endogenous PD coupling Anammox). The 1st and 2nd intermittent zones accounted for 27.2 % and 17.0 % of TIN removal, respectively, with 13.7 %-21.3 % by PNA and 3.2 %-5.3 % by PDA. Although this process did not pursue nitrite accumulation in any zone (< 1.5 mg-N/L), PNA and PDA accounted for 35.1 % and 52.1 % of TIN removal, respectively. Only 0.21 % of removed TIN was released as nitrous oxide. The AnAOB of Candidatus Brocadia was enriched in each zone, with a relative abundance of 0.66 %-2.29 %. In intermittent zones, NOB had been partially suppressed (AOB/NOB = 0.73-0.88), mainly due to intermittent aeration and effective nitrite utilization by AnAOB since its population size was much greater than NOB. Present study indicated that the three-stage AO biofilm process with intermittent aeration could enhance nitrogen removal via PNA and PDA with a low N2O emission factor.

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