Continuous and Controllable Preparation of Sodium Alginate Hydrogel Tubes Guided by the Soft Cap Inspired by the Apical Growth of the Plant.

Hydrogel tubes made of sodium alginate (SA) have potential applications in drug delivery, soft robots, biomimetic blood vessels, tissue stents, and other fields. However, the continuous preparation of hollow SA hydrogel tubes with good stability and size control remains a huge challenge for chemists, material scientists, and medical practitioners. Inspired by the plant apical growth strategy, a new method named soft cap-guided growth was proposed to produce SA hydrogel tubes. Due to the introduction of inert low gravity substances, such as air and heptane, into the extrusion needle in front of calcium chloride solution to form a soft cap, the SA hydrogel tubes with controllable sizes were fabricated rapidly and continuously without using a template through a negative gravitropism mechanism. The SA hydrogel tubes had good tensile strength, high burst pressure, and good cell compatibility. In addition, hydrogel tubes with complex patterns were conveniently created by controlling the motion path of a soft cap, such as a rotating SA bath or magnetic force. Our research provided a simple innovative technique to steer the growth of hydrogel tubes, which made it possible to mass produce hydrogel tubes with controllable sizes and programmable patterns.

Can Arthrogenic Muscle Inhibition Exist in Peroneal Muscles Among People with Chronic Ankle Instability? A Cross-sectional Study.

BACKGROUND: Ankle sprains lead to an unexplained reduction of ankle eversion strength, and arthrogenic muscle inhibition (AMI) in peroneal muscles is considered one of the underlying causes. This study aimed to observe the presence of AMI in peroneal muscles among people with chronic ankle instability (CAI). METHODS: Sixty-three people with CAI and another sixty-three without CAI conducted maximal voluntary isometric contraction (MVIC) and superimposed burst (SIB) tests during ankle eversion, then fifteen people with CAI and fifteen without CAI were randomly invited to repeat the same tests to calculate the test-retest reliability. Electrical stimulation was applied to the peroneal muscles while the participants were performing MVIC, and the central activation ratio (CAR) was obtained by dividing MVIC torque by the sum of MVIC and SIB torques, representing the degree of AMI. RESULTS: The intra-class correlation coefficients were 0.77 (0.45-0.92) and 0.92 (0.79-0.97) for the affected and unaffected limbs among people with CAI, and 0.97 (0.91-0.99) and 0.93 (0.82-0.97) for the controlled affected and unaffected limbs among people without CAI; Significant group × limb interaction was detected in the peroneal CAR (p = 0.008). The CARs were lower among people with CAI in the affected and unaffected limbs, compared with those without CAI (affected limb = 82.54 ± 9.46%, controlled affected limb = 94.64 ± 6.37%, p < 0.001; unaffected limb = 89.21 ± 8.04%, controlled unaffected limb = 94.93 ± 6.01%, p = 0.016). The CARs in the affected limbs were lower than those in the unaffected limbs among people with CAI (p = 0.023). No differences between limbs were found for CAR in the people without CAI (p = 0.10). CONCLUSIONS: Bilateral AMI of peroneal muscles is observed among people with CAI. Their affected limbs have higher levels of AMI than the unaffected limbs.

Deficits in proprioception and strength may contribute to the impaired postural stability among individuals with functional ankle instability.

Purpose: The correlations of postural stability with proprioception and strength may explain the recurrent sprains among individuals with functional ankle instability (FAI). This study aimed to compare anterior-posterior (AP) and medial-lateral (ML) postural stability, along with ankle proprioception and strength between individuals with and without FAI and investigated their correlations. Methods: Forty participants with FAI and another 40 without FAI were recruited. Their postural stability, represented by time to stabilization (TTS) in the AP (TTSAP) and ML (TTSML) directions, was calculated by the ground reaction force during jumping onto a force plate. Their ankle proprioception and strength during plantarflexion/dorsiflexion and inversion/eversion were measured using a proprioception device and a strength testing system, separately. Results: Individuals with FAI had longer TTSAP (p = 0.015) and TTSML (p = 0.006), larger ankle proprioception thresholds (p = 0.000-0.001), and less strength (p = 0.001-0.017) than those without FAI. Correlations between strength and TTSAP were detected among individuals with (ankle plantarflexion, r = -0.409, p = 0.009) and without FAI (ankle plantarflexion, r = -0.348, p = 0.028; ankle dorsiflexion, r = -0.473, p = 0.002). Correlations of proprioception (ankle inversion, r = 0.327, p = 0.040; ankle eversion, r = 0.354, p = 0.025) and strength (ankle eversion, r = -0.479, p = 0.002) with TTSML were detected among individuals without FAI but not among those with FAI. Conclusion: Individuals with FAI have worse postural stability and proprioception and less strength. Their proprioception and strength decreased to a point where they could not provide sufficient functional assistance to the ML postural stability. Improvements in proprioception and strength may be keys to prevent recurrent ankle sprains among individuals with FAI.

Abnormal Lower Limb Biomechanics During a Bilateral Vertical Jump Despite the Symmetry in Single-Leg Vertical Hop Height in Athletes After ACL Reconstruction.

Background: A limb symmetry index (LSI) of >90% for single-leg horizontal hop distance is recommended as a cutoff point for safe return to sports after anterior cruciate ligament reconstruction (ACLR). Despite achieving this threshold, abnormal lower limb biomechanics continue to persist in athletes after ACLR. Symmetry in single-leg vertical hop height appears to be more difficult to achieve and can be a better representation of knee function than single-leg horizontal hop distance. Purpose: To explore whether an LSI of >90% for single-leg vertical hop height can represent normal lower limb biomechanics in athletes during a bilateral vertical jump after ACLR. Study Design: Controlled laboratory study. Methods: According to the LSI for single-leg vertical hop height, 46 athletes who had undergone ACLR with an autologous ipsilateral bone-patellar tendon-bone or hamstring tendon graft were divided into a low symmetry group (LSI <90%; n = 23) and a high symmetry group (LSI >90%; n = 23), and 24 noninjured athletes were selected as the control group. The kinematic and kinetic characteristics during a bilateral vertical jump were compared between the low symmetry, high symmetry, and control groups. Results: During the propulsion phase of the bilateral vertical jump, the operated side in the high symmetry group showed a lower knee extension moment than the nonoperated side (P = .001). At peak vertical ground-reaction force, the operated side in the high symmetry group showed a lower knee internal rotation moment compared with the control group (P = .016). Compared with the nonoperated side, the operated side in the high symmetry group showed a higher hip extension moment (P = .002), lower knee extension moment (P < .001), lower ankle plantarflexion moment (P < .001), and lower vertical ground-reaction force (P = .023). Conclusion: Despite achieving an LSI of >90% for single-leg vertical hop height, athletes after ACLR showed abnormal lower limb biomechanical characteristics during the bilateral vertical jump. Clinical Relevance: Symmetrical single-leg vertical hop height may not signify ideal biomechanical or return-to-sports readiness in this population.

Exosomes Derived from Quercetin-Treated Bone Marrow Derived Mesenchymal Stem Cells Inhibit the Progression of Osteoarthritis Through Delivering miR-124-3p to Chondrocytes.

Osteoarthritis (OA) is a chronic disease characterized by the progressive loss of cartilage and failure of the diarrheal joint. Quercetin has been reported to attenuate the development of OA. Bone marrow derived mesenchymal stem cell (BMSC)-derived exosomes are involved in OA progression. However, the role of BMSC-derived exosomes in quercetin-mediated progression of OA remains unclear. Western blotting and RT-qPCR were used to assess protein and mRNA levels, respectively. CCK8 assay was performed to assess cell viability, and cell apoptosis was assessed using flow cytometry. A dual-luciferase assay was performed to assess the relationship between miR-124-3p and TRAF6 expression. Furthermore, in vivo experiments were performed to test the function of exosomes derived from Quercetin-treated BMSCs in OA patients. IL-1ß significantly inhibited the viability of chondrocytes, whereas the conditioned medium of Quercetin-treated BMSCs (BMSCsQUE-CM) reversed this phenomenon through exosomes. IL-1ß notably upregulated MMP13 and ADAMT5 and reduced the expression of COL2A1 in chondrocytes, which were rescued by BMSCsQUE-CM. The effects of BMSCsQUE-CM on these three proteins were reversed in the absence of exosomes. Exosomes can be transferred from BMSCs to chondrocytes, and exosomes derived from Quercetin-treated BMSCs (BMSCsQue-Exo) can reverse the apoptotic effects of IL-1ß on chondrocytes. The level of miR-124-3p in BMSCs was significantly upregulated by quercetin, and miR-124-3p was enriched in BMSCsQue-Exo. TRAF6 was identified as a direct target of miR-124-3p, and BMSCsQue-Exo abolished the IL-1ß-induced activation of MAPK/p38 and NF-κB signaling. Furthermore, BMSCsQue-Exo significantly attenuated OA progression in vivo. Exosomes derived from Quercetin-treated BMSCs inhibited OA progression through the upregulation of miR-124-3p.

Can Symmetry of Single-Leg Vertical Jump Height Represent Normal Lower Limb Biomechanics of Athletes After Anterior Cruciate Ligament Reconstruction?

BACKGROUND: After anterior cruciate ligament reconstruction (ACLR), single-leg horizontal hop distance limb symmetry index (LSI) >90% is recommended as a cutoff point for safe return to sport (RTS). However, athletes after ACLR have abnormal lower limb biomechanics despite an adequate single-leg hop distance LSI, implying that athletes are at high risk of reinjury. Symmetry of single-leg vertical jump height appears to be more difficult to achieve and can be a better representation of knee function than single-leg horizontal hop distance. HYPOTHESIS: Athletes after ACLR with single-leg jump height LSI >90% had similar biomechanical characteristics to healthy athletes. STUDY DESIGN: Controlled laboratory study. LEVEL OF EVIDENCE: Level 3. METHODS: A total of 46 athletes after ACLR were divided into low jump height (LJH, jump height LSI <90%, n = 23) and high jump height (HJH, jump height LSI >90%, n = 23) groups according to symmetry of single-leg vertical jump height, while 24 healthy athletes acted as a control (CONT) group. One-way analysis of variance was used to compare the kinematic and kinetic characteristics of the LJH, HJH, and CONT groups during single-leg vertical jump. RESULTS: Both the LJH and HJH groups demonstrated greater limb asymmetry (lower LSI) during landing compared with the CONT group in knee extension moment (P < 0.05), peak knee flexion angle (P < 0.05), and knee power (P < 0.05). CONCLUSION: Symmetry in single-leg vertical jump height does not represent normal lower limb biomechanics in athletes after ACLR. CLINICAL RELEVANCE: Symmetrical jump height may not signify ideal biomechanical or RTS readiness, but single-leg vertical jump test can be used as a supplement to horizontal hop test or other functional tests to reduce the likelihood of false-negative results in the absence of detailed biomechanical evaluation.

LC/MS Assessment of Glycoform Clearance of A Biotherapeutic MAb in Rabbit Ocular Tissues.

Many biotherapeutics such as monoclonal antibodies (mAbs) consist of various glycoforms, which can have different PK properties upon administration to animals and human. As a result, it is necessary to monitor the abundance of glycoforms and limit lot-to-lot variability during the manufacturing process. However, limited information is known about the clearance of mAb glycoforms from ocular space upon intravitreal injection. We present here an assessment of glycoform clearance of a biotherapeutic mAb (IgG1) from rabbit vitreous humor, aqueous humor and retina tissue using LC/MS. The results show that G0, G0F and G1F have similar T1/2, while mannose-5 has a longer T1/2 and is cleared slower in rabbit ocular space, which contradicted with what has been reported in the literature in which Mann5 was cleared faster systematically.

[Antifriction and anti-wear performances of bionic lubricating fluid containing gelatin nanoparticles for artificial joint materials].

Objective: The antifriction and antiwear effects of gelatin nanoparticles (GLN-NP) on artificial joint materials in bionic joint lubricant were investigated to provide a theoretical basis for the development of new bionic joint lubricant. Methods: GLN-NP was prepared by cross-linking collagen acid (type A) gelatin with glutaraldehyde by acetone method, and the particle size and stability of GLN-NP were characterized. The biomimetic joint lubricants with different concentrations were prepared by mixing 5, 15, and 30 mg/mL GLN-NP with 15 and 30 mg/mL hyaluronic acid (HA), respectively. The friction reduction and antiwear effects of the biomimetic joint lubricants on zirconia ceramics were investigated on a tribometer. The cytotoxicity of each component of bionic joint lubricant on RAW264.7 mouse macrophages was evaluated by MTT assay. Results: The particle size of GLN-NP was about 139 nm, and the particle size distribution index was 0.17, showing a single peak, indicating that the particle size of GLN-NP was uniform. In complete culture medium, pH7.4 PBS, and deionized water at simulated body temperature, the particle size of GLN-NP did not change more than 10 nm with time, indicating that GLN-NP had good dispersion stability and did not aggregate. Compared with 15 mg/mL HA, 30 mg/mL HA, and normal saline, the friction coefficient, wear scar depth, width, and wear volume were significantly reduced by adding different concentrations of GLN-NP ( P<0.05); there was no significant difference between different concentrations of GLN-NP ( P>0.05). Biocompatibility test showed that the cell survival rate of GLN-NP, HA, and HA+GLN-NP solution decreased slightly with the increase of concentration, but the cell survival rate was more than 90%, and there was no significant difference between groups ( P>0.05). Conclusion: The bionic joint fluid containing GLN-NP has good antifriction and antiwear effect. Among them, GLN-NP saline solution without HA has the best antifriction and antiwear effect.

Impulsive-Based Almost Surely Synchronization for Neural Network Systems Subject to Deception Attacks.

This article is dedicated to investigating the impulsive-based almost surely synchronization issue of neural network systems (NSSs) with quality-of-service constraints. First, the communication network considered suffers from random double deception attacks, which are modeled as a nonlinear function and a desynchronizing impulse sequence, respectively. Meanwhile, the impulsive instants and impulsive gains are randomly and only their expectations are available. Second, by taking two different types of random deception attacks into consideration, a novel mathematical model for vulnerable NSSs is constructed. Then, almost surely synchronization criteria are established by using Borel-Cantelli lemma. Furthermore, based on the derived strong and weak sufficient conditions, the almost surely synchronization of NSSs is achieved. Finally, the section of numerical example is shown to illustrate the effectiveness of the proposed method.

Practical synchronization of neural networks with delayed impulses and external disturbance via hybrid control.

This paper studies the problem of practical synchronization for delayed neural networks via hybrid-driven impulsive control in which delayed impulses and external disturbance are taken into account. Firstly, a switching method which establishes the relationship between error signals and a threshold function is introduced, which determines whether time-driven control or event-driven control is activated. Secondly, the effects of delayed impulses and external disturbance on impulsive systems are considered, and the corresponding comparison lemma is proposed. Thirdly, whenever the norm of the initial value of the error system state is less than or greater than the initial value of the threshold function, under the proposed hybrid-driven impulsive control scheme, the practical synchronization of the delayed neural networks with delayed impulses and external disturbance can be achieved by synchronizing impulses. Moreover, the Zeno behavior can be excluded under the proposed hybrid-driven impulsive control. Finally, two numerical examples are presented to verify the effectiveness of the theoretical results.

Combined fragment-based machine learning force field with classical force field and its application in the NMR calculations of macromolecules in solutions.

We have developed a combined fragment-based machine learning (ML) force field and molecular mechanics (MM) force field for simulating the structures of macromolecules in solutions, and then compute its NMR chemical shifts with the generalized energy-based fragmentation (GEBF) approach at the level of density functional theory (DFT). In this work, we first construct Gaussian approximation potential based on GEBF subsystems of macromolecules for MD simulations and then a GEBF-based neural network (GEBF-NN) with deep potential model for the studied macromolecule. Then, we develop a GEBF-NN/MM force field for macromolecules in solutions by combining the GEBF-NN force field for the solute molecule and ff14SB force field for solvent molecules. Using the GEBF-NN/MM MD simulation to generate snapshot structures of solute/solvent clusters, we then perform the NMR calculations with the GEBF approach at the DFT level to calculate NMR chemical shifts of the solute molecule. Taking a heptamer of oligopyridine-dicarboxamides in chloroform solution as an example, our results show that the GEBF-NN force field is quite accurate for this heptamer by comparing with the reference DFT results. For this heptamer in chloroform solution, both the GEBF-NN/MM and classical MD simulations could lead to helical structures from the same initial extended structure. The GEBF-DFT NMR results indicate that the GEBF-NN/MM force field could lead to more accurate NMR chemical shifts on hydrogen atoms by comparing with the experimental NMR results. Therefore, the GEBF-NN/MM force field could be employed for predicting more accurate dynamical behaviors than the classical force field for complex systems in solutions.

[Biological Conversion Mechanism of Sulfate Reduction Ammonium Oxidation in ANAMMOX Consortia].

Sulfate reduction with ammonium oxidation (SRAO) in laboratory ANAMMOX reactors was considered as an autotrophic process mediated by ANAMMOX bacteria (AnAOB), in which ammonium, as an electron donor, was oxidized by the electron acceptor sulfate. This process was developed based on the transformations of nitrogenous and sulfurous compounds observed in natural environments. Reported results vary widely for conversion mole ratios (ammonium/sulfate) as do intermediate and final products of the sulfate reduction. Thus, hypotheses surrounding biological conversion pathways of ammonium and sulfate in ANAMMOX consortia are implausible. In this study, continuous reactor experiments and batch tests were conducted under micro-aerobic (-100 mV < ORP < 0 mV, 0.5 mg·L-1 < DO < 1 mg·L-1), anoxic (-300 mV < ORP < -100 mV, 0.2 mg·L-1 < DO < 0.5 mg·L-1) and anaerobic (ORP < -300 mV, DO < 0.2 mg·L-1) conditions with different inoculated sludge (ANAMMOX sludge and mixed sludge) to verify the SRAO phenomena and identify possible pathways of substrate conversion. The key findings were that SRAO occurred only where SRB existed under anoxic condition, and was absent under anaerobic conditions with ANAMMOX consortia. The analysis of the microbial community and functional gene expression showed that ammonium oxidation by AAOB coupled with sequential ANAMMOX is possibly responsible for the loss of ammonium under anoxic condition. Organic substances released through microbial decay contributed to heterotrophic sulfate conversion by SRB. AnAOB do not possess the ability to oxidize ammonium with sulfate as the electron acceptor. SRAO could, in fact, involve a combination of aerobic ammonium oxidation, ANAMMOX, and heterotrophic sulfate reduction processes, which are mediated via AOB, AnAOB, and SRB.

First-Principles Collision Cross Section Measurements of Large Proteins and Protein Complexes.

Rotationally averaged collision cross section (CCS) values for a series of proteins and protein complexes ranging in size from 8.6 to 810 kDa are reported. The CCSs were obtained using a native electrospray ionization drift tube ion mobility-Orbitrap mass spectrometer specifically designed to enhance sensitivity while having high-resolution ion mobility and mass capabilities. Periodic focusing (PF)-drift tube (DT)-ion mobility (IM) provides first-principles determination of the CCS of large biomolecules that can then be used as CCS calibrants. The experimental, first-principles CCS values are compared to previously reported experimentally determined and computationally calculated CCS using projected superposition approximation (PSA), the Ion Mobility Projection Approximation Calculation Tool (IMPACT), and Collidoscope. Experimental CCS values are generally in agreement with previously reported CCSs, with values falling within ∼5.5%. In addition, an ion mobility resolution (CCS centroid divided by CCS fwhm) of ∼60 is obtained for pyruvate kinase (MW ∼ 233 kDa); however, ion mobility resolution for bovine serum albumin (MW ∼ 68 kDa) is less than ∼20, which arises from sample impurities and underscores the importance of sample quality. The high resolution afforded by the ion mobility-Orbitrap mass analyzer provides new opportunities to understand the intricate details of protein complexes such as the impact of post-translational modifications (PTMs), stoichiometry, and conformational changes induced by ligand binding.

Ag+ Ion Binding to Human Metallothionein-2A Is Cooperative and Domain Specific.

Metallothioneins (MTs) constitute a family of cysteine-rich proteins that play key biological roles for a wide range of metal ions, but unlike many other metalloproteins, the structures of apo- and partially metalated MTs are not well understood. Here, we combine nano-electrospray ionization-mass spectrometry (ESI-MS) and nano-ESI-ion mobility (IM)-MS with collision-induced unfolding (CIU), chemical labeling using N-ethylmaleimide (NEM), and both bottom-up and top-down proteomics in an effort to better understand the metal binding sites of the partially metalated forms of human MT-2A, viz., Ag4-MT. The results for Ag4-MT are then compared to similar results obtained for Cd4-MT. The results show that Ag4-MT is a cooperative product, and data from top-down and bottom-up proteomics mass spectrometry analysis combined with NEM labeling revealed that all four Ag+ ions of Ag4-MT are bound to the ß-domain. The binding sites are identified as Cys13, Cys15, Cys19, Cys21, Cys24, and Cys26. While both Ag+ and Cd2+ react with MT to yield cooperative products, i.e., Ag4-MT and Cd4-MT, these products are very different; Ag+ ions of Ag4-MT are located in the ß-domain, whereas Cd2+ ions of Cd4-MT are located in the α-domain. Ag6-MT has been reported to be fully metalated in the ß-domain, but our data suggest the two additional Ag+ ions are more weakly bound than are the other four. Higher order Agi-MT complexes (i = 7-17) are formed in solutions that contain excess Ag+ ions, and these are assumed to be bound to the α-domain or shared between the two domains. Interestingly, the excess Ag+ ions are displaced upon addition of NEM to this solution to yield predominantly Ag4NEM14-MT. Results from CIU suggest that Agi-MT complexes are structurally more ordered and that the energy required to unfold these complexes increases as the number of coordinated Ag+ increases.

[Stability of ZVI-dependent Autotrophic Denitrification by ANAMMOX Bacteria].

Fe0-dependent autotrophic denitrification mediated by anaerobic ammonia oxidation (ANAMMOX) bacteria was carried out in continuous flow reactors under non-strict anaerobic conditions. Three strategies, including adjusting the influent pH, adding Fe2+, and regular renewal with fresh iron powder, were used to investigate the appropriate conditions to maintain the long-term stability of this process. The results showed that the nitrate removal efficiency declined due to Fe0 passivation over time, and this ultimately led to the reaction becoming unsustainable. Neither reducing the influent pH (within the pH range 5-7) nor adding a quantity of Fe2+ had an obvious effects on the sustainability of this process. Instead, the nitrate removal efficiency and the sustainability of the reactor was enhanced significantly by regular renewal with fresh Fe0 powder. Compared with the control group (with a 7-day stable operation), the experimental setup was run steadily for at least 60 days, and the average nitrate removal efficiency was increased by 22.23%. Consequently, maintaining an adequate amount of activated Fe0 and eliminating the adverse effects of Fe0 passivation are vital for the sustainable operation of Fe0-dependent autotrophic denitrification as mediated by ANAMMOX bacteria.

[Simultaneous Conversion Conditions of Ammonia and Sulfate in ANAMMOX Systems].

A continuous flow stirred tank reactor (CFSTR) was used to inoculate mixed sludge (with an ANAMMOX sludge to sewage concentrate sludge ratio of 1:1) to study the simultaneous conversion of NH4+ and SO42-. The ORP value in the system was stabilized at (-200±50)mV by continuously adding sludge. The simultaneous conversion lasted for 42 days. The average conversion of NH4+-N was 14.81 mg·L-1 while that of sulfate-sulfur was 8.77 mg·L-1. In the batch experiment, the anaerobic conditions were influenced by whether the solution was filled with glass bottles. Both NH4+ and SO42- in the non-filled group were reduced, but their transformation was not simultaneous. In the fully filled group, NH4+ was not transformed, the concentration of SO42- decreased significantly, and S2- was detected in the later stages of the experiment. It is indicated that the general conditions for the phenomenon of simultaneous conversion are:①sufficient NH4+ and SO42-, ② inoculating mixed sludge with appropriate concentration, ③ leaking oxygen, ④ the detection value of ORP within the range of -150 to -300 mV. At the same time, the experimental conditions used in this paper and in other related literature cannot prove that the simultaneous conversion of NH4+ and SO42- is the result of mutual transformation; on the contrary, observations are more conducive to the independent transformation of NH4+ and SO42-.

Collision-Induced Unfolding of Partially Metalated Metallothionein-2A: Tracking Unfolding Reactions of Gas-Phase Ions.

Metallothioneins (MTs) constitute a group of intrinsically disordered proteins that exhibit extreme diversity in structure, biological functionality, and metal ion specificity. Structures of coordinatively saturated metalated MTs have been extensively studied, but very limited structural information for the partially metalated MTs exists. Here, the conformational preferences from partial metalation of rabbit metallothionein-2A (MT) by Cd2+, Zn2+, and Ag+ are studied using nanoelectrospray ionization ion mobility mass spectrometry. We also employ collision-induced unfolding to probe differences in the gas-phase stabilities of these partially metalated MTs. Our results show that despite their similar ion mobility profiles, Cd4-MT, Zn4-MT, Ag4-MT, and Ag6-MT differ dramatically in their gas-phase stabilities. Furthermore, the sequential addition of each Cd2+ and Zn2+ ion results in the incremental stabilization of unique unfolding intermediates.

[Analysis of CANON Process Start-up with Fiber Carrier].

A CANON reactor with fiber carrier was started up by seeding nitrification sludge and ANAMMOX sludge to study the operating characteristics of a fiber carrier. The results showed that total nitrogen removal load rose from 0.09 kg·(m3·d)-1 to 0.9 kg·(m3·d)-1 and remained steady in the 85th day. This indicated that fiber carrier is beneficial to the accumulation of sludge, and the reactor can maintain a higher biomass. The DO in the reactor reached 5 mg·L-1 with the enrichment of microorganisms, biofilm thickening, and the improvement of the reactor's ability. The DO gradient of the biofilm from the outside to the inside was 0.32-0 mg·L-1, which could be obtained by a microelectrode. It was shown that the permeability of oxygen to the biofilm decreased, and the amount of nitrifying microorganisms decreased with biofilm thickening. The quantitative PCR results showed that the abundance of ANAMMOX was an order of magnitude more than before. The abundance of AOB increased slightly, while the abundance of NOB stayed at a relatively low level.

[Start-Up and Regional Characteristics of a Pilot-scale Integrated PN-ANAMMOX Reactor].

The start-up and regional characteristics of a pilot scale integrated PN-ANAMMOX reactor was studied. The results show that inoculated nitrosation suspension filler in the anaerobic zone, ANAMMOX sludge, and common anaerobic sludge in the anaerobic zone can start the reactor quickly. The PN-ANAMMOX reactor was successfully started at 74 days. The removal rate of total nitrogen increased from 0.02 kg·(m3·d)-1 to 0.48 kg·(m3·d)-1. The analysis of the nitrogen conversion characteristics in two regions showed that the AOB had been in a dominant position in the aerobic zone, and the NOB was inhibited by DO and the matrix, NPRa increased from 0.22 kg·(m3·d)-1 to 0.58 kg·(m3·d)-1, and NAPa could reach 95% with the increase in anaerobic denitrification capacity. The anaerobic zone was a critical region of the integrated PN-ANAMMOX reactor, and NRRana increased from 0.02 kg·(m3·d)-1 to 4.7 kg·(m3·d)-1. During the start-up period (temperature decreased from 32℃ to 27℃), the changes first affected the anaerobic zone, NRRana decreased to 3.7 kg·(m3·d)-1 (about 21%), with little effect on the aerobic zone. The two regions can achieve a large ANAMMOX bacteria enrichment, as, during this time, the aerobic zone also has a certain denitrification capacity, while the anaerobic zone featured enhanced denitrification.

[Start-up and Capacity Enhancement of a Partial Nitrification Pilot Reactor in Continuous Flow].

The continuous flow reactor was used to treat simulated ammonia nitrogen wastewater by inoculating the sludge after filtration and adding a suspended filler. Regulations of free ammonia (FA), free nitrous acid (FNA), and dissolved oxygen (DO) in the reactor were the key to achieving a successful start-up of the pilot scale nitrosation reactor. The results show that the enrichment of ammonium oxidizing bacteria (AOB) and the elimination of nitrite oxidizing bacteria (NOB) are achieved by adjusting the operational mode of high DO, low DO, FA, and FNA in the reactor operation. The nitrite production rate (NPR) in the reactor was 1.27 kg·(m3·d)-1 and the nitrogen accumulation rate (NAR) was stable at 98% at the end of the start-up period. qPCR was used to study the difference in the functional microorganisms (AOB, NOB) between the beginning and the end of the start-up period. The results show that the copy number of microbial AOB grew from 5.3×109 copies·mL-1 to 1.6×1011 copies·mL-1. The copy number of NOB decreased from 1.1×1010 copies·mL-1 to 1.2×109 copies·mL-1, because of the joint regulation of DO, FA, FNA to suppress NOB.