HA Solution Research Articles

The Characteristics Analysis of Hyaluronic Acid Modified By Cold Atmospheric Plasma and Its Performance in Hydrogel Preparation

ABSTRACTHyaluronic acid (HA) is extensively utilized in biomedical applications, and its functionality can be enhanced by introducing aldehyde groups (─CHO) through oxidation. In this study, cold atmospheric plasma (CAP) was used to treat aqueous HA solutions, resulting in the formation of plasma‐modified HA (PMHA) containing ─CHO groups. The free radicals generated from interactions between water molecules and CAP particles reacted with HA, leading to the oxidation of hydroxyl groups into ─CHO and the cleavage of glycosidic bonds, causing molecular depolymerization. The PMHA was then used to synthesize hydrogels in combination with carboxymethyl chitosan and ɛ‐polylysine. This study presents an effective approach for generating HA with aldehyde functionalities and offers insights into the interaction between CAP and polysaccharides.

Polymorphism of 3-hydroxy-2-naphthoic acid: crystal structures, Hirshfeld surface analysis and properties

Polymorphs play an important role in mediating the physical properties of compounds. Therefore, a set of polymorphs based on 3‑hydroxy-2-naphthoic acid (HA), namely, α-HA (1), β-HA (2) and γ-HA·DMF (3) (DMF = N,N-dimethylformamide), were obtained by slow evaporation method, which were the solution of HA in ethanol, acetone and DMF, respectively. These crystal morphologies of HA have been characterized by single–crystal X–ray diffraction, IR and UV–Vis, and powder X-ray diffraction. In these polymorphism, classical hydrogen bonds of O–H∙∙∙O can be obviously observed, through which a supramolecular architecture will be generated. Apart from the classical hydrogen bonds, the hydrogen bonds of C–H⋯O can be only found in form γ-HA. The luminescent maximal are 497, 504 and 510 nm for α-HA,β-HA andγ-HA·DMF, respectively. The order of the maximal peaks is listed as the following: 3 > 2 > 1. Single-crystal X-ray diffraction analysis results reveal that the order of the distances between the aromatic rings is 3 > 2 > 1. The Hirshfeld analysis further confirm that there exists the largest contribution of the H∙∙∙H and H∙∙∙O close contacts in compound 3, which is in a good agreement with of the luminescent maxima in compound 3.

Facile synthesis of lignin/polyethyleneimine foams incorporating zeolitic imidazole framework-8 to efficiently remove tetracycline from aqueous solution

Lignin, as a by-product produced in the biological refining and papermaking processes, is often discarded or burned, resulting in environmental pollution and resource waste. Herein, a novel environmental-friendly ternary hybrid foams adsorbent (SLS/PEI/ZIF-8) was designed for effectively removal TC from aqueous solution. The adsorption properties of the adsorbent were systematically studied. The results show that the adsorption process for TC were fitted well by the pseudo-second-order kinetics model and the Langmuir isotherm model, respectively. The maximum Langmuir monolayer adsorption capacity of SLS/PEI/ZIF-8 for TC was calculated as 1098 mg/g at 30 °C, which was superior to most reported adsorbents. Thermodynamic analysis indicated the adsorption process for TC was spontaneous and endothermic. Moreover, the electrostatic interactions, hydrogen bonding interactions and π–π interactions were proposed as the possible adsorption mechanism. The adsorbent still maintained superior adsorption capacity for TC in ions solution, HA solution and actual water samples, and had good reusability. Therefore, it is a promising adsorbent for the removal of TC from wastewater.

Study on Electrochemical Corrosion of Q235 Steel in Sand Containing HA Solution under a Natural Air-Dried State

To explore the corrosion of Q235 steel in sand containing a simulated haze aqueous solution (HA solution) under a natural air-dried state, the effect of moisture (age) on the corrosion of Q235 steel in sand was comprehensively studied by EIS, polarization curve, SEM, EDS and XPS. The physical and chemical properties of the sand showed that the sand containing the HA solution was basically neutral under natural air drying, and the temperature was around 20 °C. After 14 days, the moisture content gradually decreased from 30% to 0%, and the salinity decreased from 1.26% to 0.04%. With the increase in age, the Eocp gradually positively skews, indicating the corrosion kinetics of the Q235 steel decrease. The impedance spectra showed that in the frequency of 10−2–103 Hz, the impedance spectra exhibited a flat capacitive loop, and the corrosion of Q235 steel was the strongest in the sand containing HA solution on the 8 d. The polarization curves showed that with increasing age, the degree of corrosion of Q235 steel changed from medium or above to slight corrosion in the sand containing HA solution. The pitting characteristics of anode branch for polarization curve also indicate the faster corrosion kinetics of Q235 steel in the early age (1–5 d). The corrosion current density Io first increased and then decreased, and the highest value was 3.44 × 10−5 A/cm2 at 6 d. The average corrosion rate was 0.1629 mm/a. HA solution accelerates the corrosion of Q235 steel in sand without HA solution (average corrosion rate, 1.51 × 10−2 mm/a). A large amount of brown-yellow corrosion products (iron oxides, about 70–200 μm) presented on the surface of the Q235 steel. The corrosion of Q235 steel belonged to local corrosion, and the corrosion pits were connected to form a large dimple-like area. The HA solution and the porous structure of sand jointly affect the electrochemical corrosion of Q235 steel.

Molecular Dynamics Investigation of Hyaluronan in Biolubrication.

Aqueous solution of strongly hydrophilic biopolymers is known to exhibit excellent lubrication properties in biological systems, such as the synovial fluid in human joints. Several mechanisms have been proposed on the biolubrication of joints, such as the boundary lubrication and the fluid exudation lubrication. In these models, mechanical properties of synovial fluid containing biopolymers are essential. To examine the role of such biopolymers in lubrication, a series of molecular dynamics simulations with an all-atom classical force field model were conducted for aqueous solutions of hyaluronan (hyaluronic acid, HA) under constant shear. After equilibrating the system, the Lees-Edwards boundary condition was imposed, with which a steady state of uniform shear flow was realized. Comparison of HA systems with hydrocarbon (pentadecane, PD) solutions of similar mass concentration indicates that the viscosity of HA solutions is slightly larger in general than that of PDs, due to the strong hydration of HA molecules. Effects of added electrolyte (NaCl) were also discussed in terms of hydration. These findings suggest the role of HA in biolubirication as a load-supporting component, with its flexible character and strong hydration structure.

Nanoparticle-Containing Hyaluronate Solution for Improved Lubrication of Orthopedic Ceramics.

Premature failure caused by inadequate lubrication of an artificial joint is a major problem. Inspired by engine lubrication, in which various additives are used to enforce the oil lubricant, here, a bench test of a biomimetic lubricating fluid containing different substances was carried out. Bovine serum albumin (BSA), in the form of both molecules and nanoparticles, was used as a functional additive. Compared with BSA molecules, BSA nanoparticles dispersed in HA solution served as more effective additives in the biomimetic lubrication fluid to minimize the friction and wear of ceramic orthopedic materials made of zirconium dioxide (ZrO2). Meanwhile, a tribo-acoustic study indicated that the “squeaking” problem associated with ZrO2 could be suppressed by the biomimetic fluid. Together with a cytotoxicity assessment, the BSA nanoparticle-incorporated biomimetic fluid was confirmed as a potential reagent for use in the clinic to maintain an even longer service life of artificial joints.

Effect of water-soluble organic acids on wettability of sandstone formations using streaming zeta potential and NMR techniques: Implications for CO2 geo-sequestration

Rock wettability is influenced by several conditions, and one such factor is the potential at the rock/fluid interface. While most studies have reported zeta potential in this context, very few investigations have carried out streaming potential measurements. Further to this, most previous studies have only evaluated zeta potential/streaming potential for NaCl brine-clean sandstone systems, while it is clear that organic matter exists in subsurface rock. However, the effect of these forms of organic matter on streaming potential has not yet been probed. Accordingly, in this study streaming potential measurements were firstly conducted on pristine San Sabasandstonesamples with 0.3 mol.dm3 NaCl brine-saturated at (6.895 MPa overburden and 3.447 MPa back-pressure). Secondly, the streaming potential of the aged samples was measured under identical conditions (the cores were saturated with aqueous HA solutions of different concentration; 1–100 mg/L) in 0.3 mol.dm−3 NaCl. Thirdly, a comparative analysis of zeta potentials was conducted via electrophoretic and streaming potential. Lastly, the T2 spectrum for the initial water saturation of pristine and aged cores, along with the T2 spectrum of residual water saturation after CO2 flooding for pristine and aged cores, were measured with NMR core flooding measurements. Accordingly, this work analyses the effects of organic acids on wettability alteration in sandstone formation in accordance with these procedures. A strong correlation exists between surface adsorption of organic acid and streaming potential coefficient, where the amount of residual water saturation decreases in humic-acid aged cores – suggesting the presence of organic acid that changes wettability towards CO2 wet in pores, where the CO2 displaces more brine in aged cores compared to pristine cores.

Mobility and Retention of Rare Earth Elements in Porous Media.

There is growing concern that rare earth elements (REEs) will become emerging soil–water contaminants because of their increased use in new technologies and products, which may lead to unavoidable release to the environment. To better understand the environmental behavior of REEs, a comprehensive set of adsorption and column transport experiments was conducted in quartz sand media. The retention and mobility of three representative REEs (La, Gd, and Er) were studied in the presence and absence of humic acid (HA; 5, 20, and 50 mg L–1) and under a range of pH conditions (5–8). Results show that REE mobility and retention are controlled by the amount of REE–HA complexes formed in a solution, which increases with increasing HA concentrations and solution pH. Gadolinium is the most mobile among the representative REEs, followed by Er and La, corresponding to the amount of (calculated) REE–HA complexes. Increasing HA concentrations in the REE solution inhibits REE retention in both the batch adsorption and column experiments. The same retardation trend was observed for lower HA concentrations (Gd > Er > La). In a fixed HA concentration, HA and REE adsorption decrease simultaneously as the solution pH increases, indicating the co-adsorption of REEs and HA on the sand. Scanning electron microscopy detection of elongated regions attached to the sand, where high REE and carbon (HA) concentrations were measured, further suggests the co-adsorption of REE–HA complexes. Modeling the column experiments shows that the time-dependent attachment is dominant at high HA concentrations, while at lower HA concentrations, both the time-dependent and spontaneous attachments play equal roles. These results provide a quantitative characterization of REE retention and mobility in sand media.

Hydroxylamine-induced oxidation of ferrous nitrobindins.

Hemoglobin and myoglobin are generally taken as molecular models of all-α-helical heme-proteins. On the other hand, nitrophorins and nitrobindins (Nb), which are arranged in 8 and 10 β-strands, respectively, represent the molecular models of all-β-barrel heme-proteins. Here, kinetics of the hydroxylamine- (HA-) mediated oxidation of ferrous Mycobacterium tuberculosis, Arabidopsis thaliana, and Homo sapiens nitrobindins (Mt-Nb(II), At-Nb(II), and Hs-Nb(II), respectively), at pH 7.0 and 20.0°C, are reported. Of note, HA displays antibacterial properties and is a good candidate for the treatment and/or prevention of reactive nitrogen species- (RNS-) linked aging-related pathologies, such as macular degeneration. Under anaerobic conditions, mixing the Mt-Nb(II), At-Nb(II), and Hs-Nb(II) solutions with the HA solutions brings about absorbance spectral changes reflecting the formation of the ferric derivative (i.e., Mt-Nb(III), At-Nb(III), and Hs-Nb(III), respectively). Values of the second order rate constant for the HA-mediated oxidation of Mt-Nb(II), At-Nb(II), and Hs-Nb(II) are 1.1 × 104M-1s-1, 6.5 × 104M-1s-1, and 2.2 × 104M-1s-1, respectively. Moreover, the HA:Nb(II) stoichiometry is 1:2 as reported for ferrous deoxygenated and carbonylated all-α-helical heme-proteins. A comparative look of the HA reduction kinetics by several ferrous heme-proteins suggests that an important role might be played by residues (such as His or Tyr) in the proximity of the heme-Fe atom either coordinating it or not. In this respect, Nbs seem to exploit somewhat different structural aspects, indicating that redox mechanisms for the heme-Fe(II)-to-heme-Fe(III) conversion might differ between all-α-helical and all-β-barrel heme-proteins.

A hyaluronic acid-based nanogel for the co-delivery of nitric oxide (NO) and a novel antimicrobial peptide (AMP) against bacterial biofilms

Biofilms are a global health concern because they are associated with chronic and recurrent infections as well as resistance to conventional antibiotics. The aim of this study was to prepare a nanogel for the co-delivery of NO and AMPs against bacteria and biofilms. The NO-releasing nanogel was prepared by crosslinking HA solution with divinyl sulfone and extensively characterized. The nanogel was found to be biocompatible, injectable and NO release from the gel was sustained over a period of 24 h. In vitro antibacterial studies showed that the NO-AMP-loaded nanogel exhibited a broad spectrum antibacterial/antibiofilm activity. The NO-releasing nanogel had a greater antibacterial effect when compared to NO alone with MIC values of 1.56, 0.78 and 0.39 μg/ml against Escherichia coli, Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa bacteria respectively. The antibiofilm results showed there was a 12.5 and 24-folds reduction in biofilms of MRSA, and P. aeruginosa respectively for catheters exposed to nanogel loaded with AMP/NO when compared to only NO, while a 7 and 9.4-folds reduction in biofilms of MRSA, and P. aeruginosa respectively was displayed by the nanogel loaded with only NO compared to only NO. The AMP/NO-releasing nanogel showed the potential to combat both biofilms and bacterial infections.

Comparative analysis of modern fault tolerance technologies

On-demand cloud applications is one of the rapidly developing technologies that highly demanded on the market. With the increase of computer systems and requirements for real-time business intelligence, potential customers of such services turn to providers of «computing on demand» services. In the data centers that used for such services, computer systems face a large amount of processed data, which in turn leads to an imbalance in the load and provokes system failures. With infrastructure as a service (IaaS) usage, customers expect efficient performance of their tasks at an optimal price. In situation, when a client submits a task for work, it is deployed on a computer system in the data center of the service provider and there is no a hundred percent assurance that task would be completed and not failed because of lack of resources or software failure. Fault tolerance and high availability issues are currently the most acute in that field. The modern set of software tools for providing fault tolerance is quite wide. In general, they are all called to ensure the trouble-free operation of the computer system, but in fact they have significant differences in conceptual terms. High availability solutions provide fully automated failover to a backup system so that users and applications can continue working without disruption. HA solutions must have the ability to provide an immediate recovery point. At the same time, they must provide a recovery time capability that is significantly better than the recovery time that you experience in a non-HA solution topology. Analyzed and compared modern fault tolerance and high availability technologies. Compared modern models of High Availability system and tools for its implementation. Identified the shortcomings of modern models and tools for fault tolerance implementing. Developed recommendations for the usage of approaches that would help to eliminate reviewed shortcomings in different cases.

Highly Effective Anti-Organic Fouling Performance of a Modified PVDF Membrane Using a Triple-Component Copolymer of P(Stx-co-MAAy)-g-fPEGz as the Additive

In this study, a triple-component copolymer of P(Stx-co-MAAy)-g-fPEGz containing hydrophobic (styrene, St), hydrophilic (methacrylic acid, MAA), and oleophobic (perfluoroalkyl polyethylene glycol, fPEG) segments was synthesized and used as an additive polymer to prepare modified PVDF membrane for enhanced anti-fouling performance. Two compositions of St:MAA at 4:1 and 1:1 for the additive and two blending ratios of the additive:PVDF at 1:9 and 3:7 for the modified membranes were specifically examined. The results showed that the presence of the copolymer additive greatly affected the morphology and performance of the modified PVDF membranes. Especially, in a lower ratio of St to MAA (e.g., St:MAA at 1:1 versus 4:1), the additive polymer and therefore the modified PVDF membrane exhibited both better hydrophilic as well as oleophobic surface property. The prepared membrane can achieve a water contact angle at as low as 48.80° and display an underwater oil contact angle at as high as 160°. Adsorption experiments showed that BSA adsorption (in the concentration range of 0.8 to 2 g/L) on the modified PVDF membrane can be reduced by as much as 93%. From the filtration of BSA solution, HA solution, and oil/water emulsion, it was confirmed that the obtained membrane showed excellent resistance to these organic foulants that are often considered challenging in membrane water treatment. The performance displayed slow flux decay during filtration and high flux recovery after simple water cleaning. The developed membrane can therefore have a good potential to be used in such applications as water and wastewater treatment where protein and other organic pollutants (including oils) may cause severe fouling problems to conventional polymeric membranes.

Hydrogen Peroxide Ammonium Citrate Extraction: Mineral Decomposition and Preliminary Waste Rock Characterization

A commonly-used method in ore exploration is hydrogen peroxide ammonium citrate (HA) extraction, which has not typically been used in waste rock characterization. In this study, the sulfide specificity and leaching of other minerals in HA extraction was evaluated and its performance was compared with the aqua regia (AR) extraction for preliminary assessment of harmful element mobility. Samples collected from several different mine sites in Finland were utilized. The waste rock sample S contents ranged from 0.3% to 5.3%, and sums of the AR extractable elements As, Cd, Co, Cu, Ni and Zn range from 120 to 8040 mg/kg. The drainage types ranged from acid high-metal to neutral low-metal, with pH’s of 3.3–7.7. Mineralogical changes that took place in the HA solution were investigated by the field emission scanning electron microscope (FE-SEM) equipped with an energy-dispersive X-ray spectroscopy analyzer (EDS) and X-ray diffraction (XRD) methods. Results of the study showed that the HA extraction appears to be a more specific method for sulfide decomposition compared with AR extraction. Sulfide minerals, especially base metal sulfides pentlandite, chalcopyrite and sphalerite, decomposed efficiently in HA extraction. However, the Fe-sulfides pyrrhotite and pyrite only decomposed incompletely. The study showed that the HA extraction results can be used in the preliminary prediction of element mobility. Based on the results, the elevated As, Cd, Co, Cu, Ni, S and Zn leachability in the HA extraction appears to predict elevated drainage concentrations. If the HA-extractable sum of As, Cd, Co, Cu, Ni and Zn is >750 mg/kg, there is an increased risk of high-metal (>1000 µg/L) drainage. Therefore, the HA extraction data, e.g., produced during ore exploration, can be utilized to preliminary screen the risks of sulfide related element mobilities from waste rock material.

Gold Nanostars Bioconjugation for Selective Targeting and SERS Detection of Biofluids.

Gold nanoparticles (AuNPs) show physicochemical and optical functionalities that are of great interest for spectroscopy-based detection techniques, and especially for surface enhanced Raman spectroscopy (SERS), which is capable of providing detailed information on the molecular content of analysed samples. Moreover, the introduction of different moieties combines the interesting plasmonic properties of the AuNPs with the specific and selective recognition capabilities of the antibodies (Ab) towards antigens. The conjugation of biomolecules to gold nanoparticles (AuNPs) has received considerable attention for analysis of liquid samples and in particular biological fluids (biofluids) in clinical diagnostic and therapeutic field. To date, gold nanostars (AuNSts) are gaining more and more attention as optimal enhancers for SERS signals due to the presence of sharp branches protruding from the core, providing a huge number of “hot spots”. To this end, we focused our attention on the design, optimization, and deep characterization of a bottom up-process for (i) AuNPs increasing stabilization in high ionic strength buffer, (ii) covalent conjugation with antibodies, while (iii) retaining the biofunctionality to specific tag analyte within the biofluids. In this work, a SERS-based substrate was developed for the recognition of a short fragment (HA) of the hemagglutinin protein, which is the major viral antigen inducing a neutralizing antibody response. The activity and specific targeting with high selectivity of the Ab-AuNPs was successfully tested in transfected neuroblastoma cells cultures. Then, SERS capabilities were assessed measuring Raman spectra of HA solution, thus opening interesting perspective for the development of novel versatile highly sensitive biofluids sensors.

Comparison of Skin Antiseptic Agents and the Role of 0.01% Hypochlorous Acid.

BackgroundHypochlorous acid (HA) has both anti-microbial and wound-healing properties with a growing role for utilization in pre-procedural care on the face.ObjectivesThe authors sought to compare the antiseptic property of 0.01% HA solution, 5% povidone iodine (PI), 4% chlorhexidine gluconate (CHG), and 70% isopropyl alcohol (IPA) antiseptic on facial skin.MethodsThis was a prospective single-center clinical trial.ResultsA total of 21 participants were recruited. Bacterial growth was seen in CHG (10%), IPA (71%), PI (81%), and HA (95%) of specimens (P < 0.001). CHG had less growth compared with HA (P = <0.001), IPA (P = <0.001), and PI (P = <0.001). No difference in bacterial growth was noted between HA and IPA (P = 0.063) or HA and PI (P = 0.25). Significant differences in mono-microbial and poly-microbial growth were seen between HA and IPA (P = 0.046) and HA and CHG (P = <0.001). Staphylococcus epidermidis grew less frequently in CHG (10%), followed by IPA (29%), PI (71%), and HA (71%). Staphylococcus capitis grew less frequently in CHG (0%), followed by PI (14%), HA (24%), and IPA (29%).ConclusionsCHG reduced the bacterial growth compared with HA, PI, and IPA. However, HA, PI, and IPA had insignificant differences in bactericidal effects. Our study provides a supporting role of HA to be considered as an antiseptic.Level of Evidence: 2

Shear-Thinning Viscous Materials for Subconjunctival Injection of Microparticles.

While drug-loaded microparticles (MPs) can serve as drug reservoirs for sustained drug release and therapeutic effects, needle clogging by MPs poses a challenge for ocular drug delivery via injection. Two polymers commonly used in ophthalmic procedures-hyaluronic acid (HA) and methylcellulose (MC)-have been tested for their applicability for ocular injections. HA and MC were physically blended with sunitinib malate (SUN)-loaded PLGA MPs for subconjunctival (SCT) injection into rat eyes. The HA and MC viscous solutions facilitated injection through fine-gauged needles due to their shear-thinning properties as shown by rheological characterizations. The diffusion barrier presented by HA and MC reduced burst drug release and extended overall release from MPs. The significant level of MP retention in the conjunctiva tissue post-operation confirmed the minimal leakage of MPs following injection. The safety of HA and MC for ocular applications was demonstrated histologically.

Enhancing the permeance and antifouling properties of thin-film composite nanofiltration membranes modified with hydrophilic capsaicin-mimic moieties

Enhancing the water permeance and improving the antifouling performance of developing thin film composite (TFC) nanofiltration (NF) membranes remains a great challenge for practical applications. In this work, a novel TFC membrane was fabricated by introducing a new capsaicin derivative (propyl 2-(acrylamidomethyl)-3,4,5-trihydroxybenzoate, PAMTB) into a polyamide (PA) layer during interfacial polymerization for the NF process. The abundant hydroxyl groups in the PAMTB molecules can compete with the amino group in piperazine (PIP) to react with acyl chloride in trimesoyl chloride (TMC), facilitating the formation of a smooth and hydrophilic membrane surface with an enlarged pore size to promote water permeance. Compared to the control TFC membrane, the PAMTB-incorporated membrane exhibited increased water flux from 80 L m-2h-1 to 115 L m-2h-1 and a steady rejection of above 98.0% with 2.0 g L-1 Na2SO4 as the feed solution under a pressure of 5.0 bar. Different measurement methods demonstrated that the TFC-PAMTB membrane exhibited superior antifouling properties and long-term stability. In particular, the permeation flux recovery was approximately 100% after simple hydraulic washing with HA solution as the foulant. This work introduced a new approach to exploit capsaicin-mimic moieties in water treatment applications.

Increasing Concentration of Sinovial: Effect on Cartilage Protection in a Rabbit ACLT Model.

This study aimed to test the hypothesis that administration of increasing doses of Sinovial (hyaluronic acid [HA]), would exhibit a dose-dependent effect on the prevention of cartilage degradation, without local and systemic toxicity. Twenty-seven adult rabbits were subjected to anterior cruciate ligament transection (ACLT). Two Sinovial products containing HA concentrations of 1.6% and 2.4% were used as active treatment, and 0.9% saline was used as control and injected intra-articularly 7 days post ACLT. Radiographs were taken prior to surgery, at injection and sacrifice times. After euthanasia, 8 weeks postsurgery, knee joints were observed macroscopically using India ink staining with OARSI (Osteoarthritis Research Society International) scoring and histologically using modified Mankin scoring. The synovial membranes were analyzed using Cake classification. No intraoperative complications were observed. One week postinjection, 4 animals in the HA 2.4% group developed subcutaneous nodules that disappeared spontaneously. No inflammation of the synovial membrane was ever observed. The control group exhibited the maximum uptake of India ink 2.22 ± 0.14. HA groups exhibited a dose-dependent (P = 0.02) reduction in India ink uptake: 1.75 ± 0.17 for HA 1.6% and 1.58 ± 0.14 for HA 2.4%. The most marked dose-dependent effect of this study was a reduction of modified Mankin score for HA groups, with the 2.4% treatment achieving a statistically significant improvement as compared with the control group (7.19 ± 0.85 for saline, 4.65 ± 0.66 for HA 1.6%, and 3.53 ± 0.59 for HA 2.4%; P = 0.005). A dose-dependent protective effect on cartilage was observed after injection of both HA solutions.

The pH Calculation of the Mixed Weak Acids of HA and HB Solutions

The pH Calculation of the Mixed Weak Acids of HA and HB Solutions

Chemical-grafting of graphene oxide quantum dots (GOQDs) onto ceramic microfiltration membranes for enhanced water permeability and anti-organic fouling potential

In this work, graphene oxide quantum dots (GOQDs) with an average size of around 3.8 nm were prepared by facile hydrolysis of citric acid. Subsequently, GOQDs were immobilized onto the (3-aminopropyl) triethoxysilane (APTES) functionalized alumina membrane surface by covalent bonding. The effects of GOQDs on the surface properties including the pore size, hydrophilicity and surface roughness, as well as water permeability and anti-organic fouling properties of ceramic membranes were systematically studied. The ceramic membranes modified by GOQDs could remain a porous structure with reduced surface roughness and improved hydrophilicity. Notably, the surface modification by GOQDs slightly decreases the average pore size from 200.8 nm to 191.3 nm, and the uniformity in pore size is improved at the same time. As a result, the GOQDs modified ceramic membranes show improved water permeability with an enhanced pure water flux (~30%) and reduced membranes resistance (~15%). Importantly, GOQDs modified ceramic membranes show much higher pure water flux and lower filtration resistance both before and after the static adsorption experiment, which compare favorably with those unmodified ones. In addition, the GOQDs modified ceramic membranes also show improved fouling resistance in HA solution under submerged conditions.