Decrease In Surface Area Research Articles

Comparison of medial tibiofemoral joint mechanics between all-suture anchors and transtibial pullout technique for posterior medial meniscal root tears

BackgroundThe posterior medial meniscal root tear (PMMRT) seriously impacts the tibiofemoral joint biomechanics. Two available techniques for PMMRT repair include the transtibial pullout (TPO) repair and all-suture anchor (ASA) repair techniques. These techniques have not been compared biomechanically.MethodsA total of 20 fresh porcine cadaveric knee specimens were used. All 20 knees were randomly and evenly distributed into four groups (five specimens per group): (1) intact posterior meniscal root, (2) PMMRT, (3) TPO repair technique for PMMRT, and (4) ASA repair technique for PMMRT. The tibiofemoral contact mechanics were investigated using a pressure sensor. All knee specimens were tested by being loaded with 600 N axial compressive force at three different flexion angles (0°, 45°, and 90°). The contact surface area, contact pressure, peak pressure, and time-zero displacement were recorded.ResultsThe PMMRT caused a significant decrease in contact surface area, an increase in contact pressure, and peak pressure from the reference values observed in the intact meniscus group (P = 0.05, 0.016, and 0.008, respectively). After fixation, no significant difference was observed between the ASA and intact group. Meanwhile, significant differences were found between the TPO and intact group in terms of contact surface area, contact pressure, and peak pressure. In the comparison between the two techniques, the ASA group demonstrated higher contact surface area than the TPO group at the average knee flexion angle (p = 0.05).ConclusionFor most testing conditions, the ASA technique demonstrated superior biomechanical property in terms of contact surface area compared with the TPO technique under compressive loading conditions. The ASA technique could also restore the tibiofemoral contact mechanics to be comparable with those of the native intact knee. Meanwhile, a significant difference in tibiofemoral mechanics, compared with the intact knee, could be observed in the TPO technique.

Factors Influencing the Expansion of Arch-Shaped Electromagnetic Railguns with Pre-Stressed Composite Barrels.

Rail expansion significantly impacts the launch precision of a railgun system. Higher precision can be achieved when the extent of expansion is low. This paper investigates three main factors that influence the extent of rail expansion using the finite element method, including pre-stress, electromagnetic load, and stiffness of the insulators. The mean squared error between experiment results and simulating results is less than 0.06, validating the finite element model. The simulated results reveal that the extent of rail expansion increases with a decrease in pre-stress and an increase in electromagnetic pressure and the stiffness of the insulator is the most significant influencing factor, as the use of a stiff insulator not only results in a small extent of rail expansion but also delays the separation between the rails and insulators. The mechanism of how pre-stress influences the railgun system has been proposed. It has been expressed that the pre-stress maintains the integrity of the railgun system by hindering the process of a decrease in the contact surface area between rails and insulators during launch. The study provides a platform to improve the design of the railgun system.

Microstructure of Fe(OH)3 phase in hydration products of calcium sulfoaluminate cement

The Fe(OH)3 phase is one of the important hydration products in Ferric-rich calcium sulfoaluminate (FR-CSA) cement and is an essential contributor to the desirable properties of FR-CSA. However, Fe(OH)3 phase has always been investigated as an auxiliary component of the cement hydration system, and the understanding of the microstructure of Fe(OH)3 phase seems to have not been clarified. Therefore, in order to thoroughly investigate the microstructure of the Fe(OH)3 phase to determine the formation process of this phase. In this study, the Fe(OH)3 phase was synthesized from chemical composition using the sol–gel method, and compared with the hydration product Fe(OH)3 of the ferric phase prepared by solid-phase sintering. The microstructure of the Fe(OH)3 phase was investigated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-Brunauer Emmett Teller (BET) and Mössbauer spectroscopy. The results indicate that Fe(OH)3 phase exists in the form of crystals at different pH, and the crystallinity of Fe(OH)3 phase gradually increases with the increase of pH. At low pH (<10), the Fe(OH)3 phase is microcrystalline (ferrihydrite), while high pH (>10) favours stable Fe(OH)3 (goethite) crystal structures to be obtained. In addition, with the increase of pH, the micro-morphology of Fe(OH)3 phase changes from granular to needle-like, and the particle size (length) gradually increases and the specific surface area decreases. No evidence of amorphous Fe(OH)3 was found during hydration, and XRD, TEM and Mössbauer spectroscopy indicated that Fe(OH)3 has a distinct crystal structure. Compared with the chemically synthesized Fe(OH)3 phase, the hydrated Fe(OH)3 phase exists in a microcrystalline state with a flaky microscopic morphology and smaller particle size.

On the benefits of vegetable oil addition for the pore structure and acid resistance of alkali-activated systems

The impact of high additions of vegetable oil (12 vol%) on the mechanical and microstructural properties of metakaolin-slag-based alkali-activated materials (AAMs) was studied. The addition of oil resulted in a slight decrease in initial polymerization kinetics but did not affect the final degree of reaction. AAM-oil-composite-mortars exhibited approximately ∼30% lower compressive strength primarily due to the entrainment of air voids. Newly formed soap phases significantly reduced the volume of small capillary and gel pores (pore radii <15 nm), leading to a decrease in specific inner surface area by a factor of up to 15. The porosity modification induced by the oil addition greatly enhanced the resistance of AAMs against sulfuric acid attack, shifting the dominant processes from diffusion and cracks to framework-dissolution controlled by the inherent phase stabilities. Following the immersion in sulfuric acid (pHstat = 2) for 8 weeks, the depth of corroded layer decreased by 70% and no cracks due to expansive phases were observed. These promising findings suggest that the incorporation of vegetable oil in AAMs has the potential to address durability concerns associated with diffusion-based corrosion processes, thereby expanding the range of future applications.

Insights into the effect of oxygen functional groups on the heterogeneous electron transfer at activated carbons from scanning electrochemical microscopy

The influence of surface chemistry on heterogeneous electron transfer at activated carbon (AC) electrodes was studied using scanning electrochemical microscopy (SECM) and conventional electrochemical measurements, which allow for measuring respectively the local and the overall electrode electron transfer rate constants. Using a thermal treatment in air and under argon, commercial activated carbons were either oxidized or defunctionalized. Both treatments lead to a slight decrease of the specific surface area of the material, without altering its pore size distribution and morphology. The nanogap voltammetry and approach curves obtained by SECM were used to characterize the rate constants at the interface between an aqueous solution of ferrocenemethanol (FcMeOH) and the AC electrodes. The heterogeneous electron transfer (HET) rate constant for the untreated AC was 3.4 10−2 ± 0.2 cm s−1 and was increased by about 2.5 and 1.5 times, after oxidizing and defunctionalizing the surface, respectively. SECM results showed that the heat treatment increases the conductivity of AC, and the oxidation of the surface increases the wettability and accessibility of the pores, which are assumed to promote the electron transfer. The local heterogeneous electron transfer rate constant values obtained by SECM are higher, by an order of magnitude, than the global ones obtained from conventional electrochemical macroelectrode measurements. The local information obtained by SECM is valuable for understanding the nanoscale interfacial mechanisms in porous carbon electrodes as a better understanding of the charge storage mechanism is key to improve their electrochemical performances.

Glycerol carbonate synthesis over nanostructured titanate catalysts: Effect of morphology and structure of catalyst

The indirect conversion of CO2 into glycerol carbonate using DMC was investigated using pristine sodium titanate nanotubes (NaTNT) and nanostructured titanates (calcined NaTNT at different temperatures) as catalysts. The calcination changes the morphology of the nanostructured titanates, between 200 and 400 °C the nanotubes shape is retained, however above these temperatures (500 and 600 °C) nanoribbons were identified, as well as nanorods obtained at 700 °C. A significant decrease in specific surface area and total pore size in temperatures up 500 °C was also observed. Furthermore, a decrease in the Ti+4/Ti+2 ratio and in the binding energy of Ti 2p3/2 and Ti 2p1/2 were observed, indicating an increase in the electron density and consequently increase in the Lewis acidity character of the titanium atom. All the nanostructured titanates showed good catalytic activity with glycerol conversion and GC selectivity above 90%. The results of the recycling showed that the nanostructured catalysts retained a good catalytic activity with high glycerol conversion (> 90%) although the GC selectivity decreased due the formation of glycidol, a high value-added by-product.

CO2 methanation over NiO catalysts supported on CaO–Al2O3: Effect of CaO:Al2O3 molar ratio and nickel loading

This study conducted the CO2 methanation reaction over the nickel-based catalysts supported on CaO.Al2O3 with different CaO/Al2O3 molar ratios. The catalyst support was synthesized with the mechanochemical method, and the influence of nickel loading was investigated on the selected catalyst support with an appropriate CaO/Al2O3 molar ratio. According to the results, incorporating Al2O3 into the CaO increased the BET area from 5 to 196 m2 g−1. Also, the SBET of the calcined catalysts decreased with the augmentation of nickel oxide percentage from 5 to 15 wt% due to the pore blocking of the support after metal addition. Moreover, the activity of catalysts enhanced with the increment of CaO/Al2O3 molar ratio and NiO percentage, ascribed to the improvement in the reducibility of the catalysts. However, the excessive addition of CaO and nickel oxide reduced the CO2 conversion because of a significant decrease in surface area. Therefore, 10 wt% NiO/CaO.2Al2O3 catalyst possessed superior CO2 conversion (79.1%) and CH4 selectivity (98.1%) in CO2 methanation reaction at 450 °C, H2/CO2 = 4 and GHSV = 18,000 ml h−1.g−1cat. The selected sample illustrated great stability for 11 h without any remarkable change in its initial catalytic activity. The impact of GHSV on the catalytic performance of the selected catalyst was evaluated, and the outcomes exhibited that decrement in GHSV value enhanced CO2 conversion. With the increment of feed ratio (H2/CO2) from 2 to 5, CO2 conversion reached 93.3%, ascribed to the existence of adequate hydrogen to react with CO2.

Characteristics of rabbit hapten-specific and germline-based BCR repertoires following repeated immunization

The rabbit is well known for producing diverse antibodies against various antigens including small molecules such as drugs and toxins, due to a robust immune response. Elucidating how hapten repeated immunization shapes the rabbit B cell receptor (BCR) repertoire is crucial to understanding rabbit immune response to small molecules and assisting rare antibody discovery/engineering. In this study, we enriched and sequenced chloramphenicol (CAP)-specific rabbit B cells following repeated immunization, and analyzed both CAP-specific repertoires combined with the structure and affinity features of V1S69/V1S37 germline-based BCRs. The length of rabbit complementarity-determining region 3 of heavy chain (CDRH3) increased after hapten immunization. Repeated immunization significantly reduced the diversity of CAP-specific rabbit BCR clonotypes, and changed the frequency of VDJ usage and the type of V(D)J recombination. The average number of mutations among VL is notably higher than that of VH genes in rabbits, however, they are both not changed along with repeated immunization. Moreover, repeated immunization resulted in an increase surface charge and a decrease in solvent accessible surface area, leading to improvement in the stability of the most abundant V1S69/V1S37 germline-based BCR, along with an affinity increase from an IC50 of 898.2 ng mL−1 at the 1st immunization to 4.16 ng mL−1 at the 6th immunization. The study provides a benchmark for rabbit repertoire-scale analyses and offers a method for antibody discovery of small molecules.

Structural and sorption properties of nanoporous carbon materials obtained from walnut shells

Using the method of low-temperature nitrogen adsorption/desorption, the porous structure of nanoporous carbon materials obtained by alkaline activation of light industry waste (walnut shells) with subsequent thermal modification was investigated. The optimal relationship between temperature and modification time has been established. It is shown that an increase in the modification temperature reduces the transition time of micropores into mesopores and leads to a decrease in the specific surface area and total pore volume. Thus, the material obtained at a modification temperature of 400 ºC and a holding time of 120 min is characterized by the maximum specific surface area of 940 m2/g. It has been investigated that an increase in the time of temperature modification leads to an increase in specific electrical conductivity.

Response of pore network fractal dimensions and gas adsorption capacities of shales exposed to supercritical CO2: Implications for CH4 recovery and carbon sequestration

The injection of CO2 into shale reservoirs potentially increases rates and masses of CH4 recovery and simultaneously contributes to the sequestration of CO2. At typical reservoir conditions (T≥31.08 °C, P≥7.38 MPa) the CO2 will be supercritical. We compile, analyze, and supplement experimental data of shales from several basins across China, and use X-ray diffraction, scanning electron microscopy and low-pressure gas adsorption to characterize variations in shale pore structure before and after supercritical CO2 (ScCO2) treatment, and supplement these with CH4/CO2 adsorption experiments to characterize changes in shale adsorption capacity. The results show that clay and carbonate contents significantly decrease, and the relative content of quartz is increased after ScCO2 treatment. Pore structure changes significantly after ScCO2 treatment, with the majority of the shales showing a decrease in total specific surface area and total pore volume and an increase in average pore size — indicating the transformation of some micropores and smaller mesopores into mesopores and macropores. After ScCO2 treatment, the experimentally derived absolute adsorption volumes of both CH4 and CO2 decrease, and the volumes of both CH4 and CO2 fitting a Langmuir isotherm decrease with an increase in treatment pressure and increase with an increase in temperature. The adsorption selectivity factors αCO2/CH4 all remain greater than 1 with αCO2/CH4 primarily controlled by the pore structure. The fractal dimension is positively correlated with Langmuir volume and negatively correlated with Langmuir pressure while the fractal dimensions are negatively correlated with αCO2/CH4. The selectivity factor αCO2/CH4 decreases rapidly above a fractal dimension threshold (D1>2.65, D2>2.80). This paper further reveals critical interactions between ScCO2 and shale and defines controls on and of pore structure and adsorption capacity to speculate on physical and chemical storage mechanisms of CO2 in shale reservoirs. This provides several theoretical bases for shale gas recovery and the sequestration of CO2.

Ternary Ni-Ce-Mg-O Composites: In-Depth Optical Spectroscopy Study and Catalytic Performance in CO Oxidation

In the present work, ternary Ni-Ce-Mg-O composites containing various amounts of NiO and CeO2 were synthesized via a sol-gel approach. Aqueous solutions of cerium and nickel nitrates were introduced at the stage of hydrolysis of magnesium methoxide, which allowed for avoiding the use of expensive organic precursors. It was revealed that the properties of the composites were defined by the complex interactions between NiO, CeO2, and MgO components. In order to perform an in-depth characterization of the prepared samples, diffuse reflectance UV–vis and Raman spectroscopies were applied. According to the results of these methods, Mg2+ ions did not substitute Ce4+ ions in the CeO2 lattice. However, in the case of the Ni-containing samples, approximately 2–3% of the Ce4+ ions were substituted by Ni2+, thus resulting in the formation of vacancies in the CeO2. The strong interaction of NiO with MgO predictably resulted in the formation of NixMg1−xO solid solutions. When the NiO content in the sample was 20 wt%, the composition of the formed solid solution was estimated to be Ni0.60Mg0.40O. In addition, the presence of CeO2 affected the texture of the ternary composites, thus leading to a slight decrease in the specific surface area. The catalytic performance of the Ni-Ce-Mg-O composites was examined in the CO oxidation reaction under prompt thermal aging conditions. The choice of reaction conditions was due to a high sensitivity of the CO oxidation response toward the available metal surface area and possible metal-support interactions.

Effects of alkali and alkaline earth metals on the activity and stability of Pd/SSZ-13 for passive NOx adsorption

Pd/SSZ-13 has been proposed as a passive NOx adsorber (PNA) to effectively alleviate NOx emission during vehicle cold start. However, the chemical poisons which are derived from biodiesel and lubricant oil are challenging for the practical application of PNA technology. In this paper, Pd/SSZ-13 was poisoned by alkali/alkaline earth metals to investigate the effects of chemical poisons on the adsorption performance of Pd/SSZ-13. It was found that the alkali/alkaline earth metals led to the decrease of surface area and Brønsted acid sites of Pd/SSZ-13. Strikingly, the 27Al MAS NMR demonstrated that the alkali/alkaline earth metals could effectively prevent Pd/SSZ-13 from dealumination during hydrothermal aging treatment. The H2-TPR results showed that more than 70% of Pd2+ ions were lost in the Na- and K-impregnated Pd/SSZ-13, while almost complete loss of Pd2+ ions was observed in the Mg- and Ca-impregnated Pd/SSZ-13, which resulted in the deactivation of Pd/SSZ-13. Further, the DRIFTS results showed that Mg2+ and Ca2+ ions exhibited preferential substitution for Pd2+ ions, while Na+ and K+ ions preferentially replaced the H+ ions. This work provides insights into the effects of alkali/alkaline earth metals on Pd/SSZ-13, expecting to attract attention to design PNA materials with resistance to chemical poisons.

Super-oxidized “activated graphene” as 3D analogue of defect graphene oxide: Oxidation degree vs U(VI) sorption

Porous carbons are not favorable for sorption of heavy metals and radionuclides due to absence of suitable binding sites. In this study we explored the limits for surface oxidation of “activated graphene” (AG), porous carbon material with the specific surface area of ∼2700 m2/g produced by activation of reduced graphene oxide (GO). Set of “Super-Oxidized Activated Graphene” (SOAG) materials with high abundance of carboxylic groups on the surface were produced using “soft” oxidation. High degree of oxidation comparable to standard GO (C/O=2.3) was achieved while keeping 3D porous structure with specific surface area of ∼700–800 m2/. The decrease in surface area is related to the oxidation-driven collapse of mesopores while micropores showed higher stability. The increase in the oxidation degree of SOAG is found to result in progressively higher sorption of U(VI), mostly related to the increase in abundance of carboxylic groups. The SOAG demonstrated extraordinarily high sorption of U(VI) with the maximal capacity up to 5400 μmol/g, that is 8.4 – fold increase compared to non-oxidized precursor AG, ∼50 –fold increase compared to standard graphene oxide and twice higher than extremely defect-rich graphene oxide. The trends revealed here show a way to further increase sorption if similar oxidation degree is achieved with smaller sacrifice of surface area.

The Adsorption Performance of Porous Activated Carbons Prepared from Iron (II) Precursors Precipitated on the Porous Carbon Matrix Thermolysis

The creation of new compounds featuring high adsorption and catalytic performance with magnetic properties of the material is one of the important fields of magnetochemistry. The typical synthetic schemes of magnetic carbonaceous adsorbents are rather complicated due to the use of inert atmosphere and difficult wet methods of magnetite precipitation. The arising experimental issues prevent industrial production of magnetically activated carbons. In order to overcome these obstacles, we suggested a novel approach to porous carbons: magnetite composite synthesis based on iron (II) salt precipitation on porous carbon and subsequent thermolysis. We facilitated the process at the stage of the material washing. The synthetic route used is simple and can be applied industrially. The present paper is focused on the adsorption performance of a product prepared from commercial activated carbons BAU-A and AG-3. The porous structure was studied with low-temperature nitrogen adsorption that revealed surface area decreased by 26% in the case of BAU-A and 40% in the case of AG-3 with an increase in mesopore volume. Phenol and nitrobenzene adsorption from water solution was tested with magnetic carbon prepared from BAU-A. The adsorption isotherms obtained are described well using the Langmuir model. The limiting adsorption value in the case of magnetic porous carbon is lower than in the case of pristine carbon. The relative decrease in limiting adsorption value is close to the relative decrease in the specific surface area. The adsorption constant remains the same, showing that adsorption centers of phenol and nitrobenzene are the same for porous magnetic carbon and its activated carbon precursor. Thus, we showed in the present study that the magnetically activated carbons we developed almost retain the adsorption performance of their activated carbon precursors.

Catalytic dehydration of fructose to 5-hydroxymethylfurfural over mesoporous Nb-W oxide solid acid catalyst

In this study, a mesoporous Nb-W oxide solid acid catalyst was synthesized and characterized in detail by TEM, N2 physisorption, and Py-FTIR. Effects of the calcination temperature on the pore structure and acid properties were investigated. The results showed that increasing calcination temperature from 400 °C to 600 °C remarkably affected the characteristics of mesoporous Nb-W oxides, with a decrease in specific surface area, pore volume, and acid amount, but an increase in pore size from 5.1 nm to 10.4 nm. Furthermore, a notable decrease was found in both the fructose conversion and HMF yield in the dehydration of fructose to HMF over Nb-W oxides when increasing the calcination temperature, and the catalyst could keep high catalytic activity and selectivity after recycling 4 times. Solvents also played a key role in the fructose dehydration to HMF over the Nb-W oxides, and DMSO was the optimized solvent. 1H NMR and 13C NMR experiments revealed that the key intermediate, 4-hydroxy-5-hydroxymethyl-4,5-dihydrofuran-2-carbaldehyde, could generate in DMSO but not in other solvents including NMP, DMF, DMAC, and EG.

Hierarchical porous composites derived from spent tire char for CO2 capture: K-N co-doped, process intensification and thermodynamic analysis

Spent tire is a kind of solid waste with large production, accumulation and great pollution. Spent tire char is the primary product of tire harmless disposal. Its commercial value is enhanced by modification. In this study, K-N co-doped activated carbon was prepared by using spent tire char as raw material, KOH and melamine as activator and dopant to enhance CO2 capture. In comparison with traditional process, the reasons for the decrease in specific surface area and pore volume caused by K doped have been identified, and a potential doped mechanism has been proposed. It was determined that pyridine nitrogen in the amino functional group played a key role in CO2 adsorption. Meanwhile, the synergistic intensification of CO2 adsorption by potassium phenolic and pyridine nitrogen was verified by simplified model simulation. The precise K-N doping significantly intensify the CO2 adsorption capacity of spent tire char from 0.45 to 2.60 mmol/g (1 bar, 0℃), an increase of 4.78 times. Thermodynamic studies have demonstrated that the Langmuir model accurately describes the adsorption process, and the adsorption reaction takes place spontaneously at temperatures below 80.52 °C. This work presents an efficient process for upgrading spent tire char, and a novel method of co-treating waste and CO2.

Very Large Pores Mesoporous Silica as New Candidate for Delivery of Big Therapeutics Molecules, Such as Pharmaceutical Peptides.

The synthesis of a scaffold that can accommodate big molecules with a pharmaceutical role is important to shield them and maintain their biological activity. In this field, silica particles with large pores (LPMS) are innovative supports. Large pores allow for the loading of bioactive molecules inside the structure and contemporarily their stabilization and protection. These purposes cannot be achieved using classical mesoporous silica (MS, pore size 2-5 nm), because their pores are not big enough and pore blocking occurs. LPMSs with different porous structures are synthesized starting from an acidic water solution of tetraethyl orthosilicate reacting with pore agents (Pluronic® F127 and mesitylene), performing hydrothermal and microwave-assisted reactions. Time and surfactant optimization were performed. Loading tests were conducted using Nisin as a reference molecule (polycyclic antibacterial peptide, with dimensions of 4-6 nm); UV-Vis analyses on loading solutions were performed. For LPMSs, a significantly higher loading efficiency (LE%) was registered. Other analyses (Elemental Analysis, Thermogravimetric Analysis and UV-Vis) confirmed the presence of Nisin in all the structures and its stability when loaded on them. LPMSs showed a lower decrease in specific surface area if compared to MS; in terms of the difference in LE% between samples, it is explained considering the filling of pores for LPMSs, a phenomenon that is not allowed for MSs. Release studies in simulated body fluid highlight, only for LPMSs, a controlled release, considering the longer time scale of release. Scanning Electron Microscopy images acquired before and after release tests shows the LPMSs' maintenance of the structure, demonstrating strength and mechanical resistance of structures. In conclusion, LPMSs were synthesized, performing time and surfactant optimization. LPMSs showed better loading and releasing properties with respect to classical MS. All collected data confirm a pore blocking for MS and an in-pore loading for LPMS.

Utilizing bioinspired AgNPs as an antibacterial agent to enhance ceramic membrane performance

In this study, a ceramic membrane using kaolin (40% w/w) as a primary precursor was fabricated by the uniaxial dry compaction technique at a sintering temperature of 900 °C (as negligible weight loss >850 °C) and functionalized by bioinspired Ag nanoparticles (AgNPs) synthesized using Sechium edule extract for the treatment of sewage water. The Ag+ adsorption of 99% on the bare membrane was achieved at pH 7. The X-ray diffraction pattern not only confirmed significant phase transformations during the sintering operation but also the presence of highly crystalline AgNPs in the modified membrane. UV-Vis spectroscopic analysis was used to study AgNPs formation based on surface plasmon effect, if any, on the modified membrane surface. AgNPs modified membrane showed a 60.5% decrease in surface area compared to bare membrane due to AgNPs impregnation. AgNPs (average size 29.54 nm) exhibited a uniform morphological distribution on the modified membrane, which decreased its average pore size and porosity from 3.09 to 2.64 µm and 47.91–44.97%, respectively. The pure water flux of bare and AgNPs modified membranes were 8.1 ± 0.09 × 10−4 and 6.33 ± 0.12 × 10−4 m3.m−2.s−1, respectively. The antimicrobial activity of bare membrane against E. coli, S. aureus, and bacterial strains in sewage water was found to be 37.03 ± 2.73, 52.64 ± 3.49, and 53.03 ± 6.80%, respectively. AgNPs functionalized ceramic membrane could completely (∼100%) inhibit the growth of E. coli, S. aureus, and bacterial strains in sewage water during filtration.

Chronic glial activation causes cholinergic cell loss in the basal forebrain during pathological aging

AbstractBackgroundNeuroinflammation, described by chronic glial reactivation lead to gradual neurodegeneration during pathological aging, contributing to disorders like Alzheimer’s disease (AD). Cholinergic cell loss in the basal forebrain (BF) including the medial septum (MS) is associated with AD; however the underlying mechanism is still unknown. Hence, this study investigated the effects of aging and chronic neuroinflammation on the MS cholinergic cell numbers and morphology.MethodAged, 12 and 24 months WT and GFAP‐IL6 mice (presenting IL‐6 overexpression under the GFAP promoter, resulting in chronic glial activation) were used. Immunohistochemistry combined with unbiased stereology and 3D morphology analysis were used to estimate the number and morphology of Iba1+ microglia and ChAT+ cholinergic cells in the MS. Transcriptomic analysis of the MS was performed using qPCR.ResultStereological estimation of MS microglia number displayed a significant 25% increase in GFAP‐IL6 mice compared to control WT (12M). A significant 30% increase was obtained for GFAP‐IL6 (24M) mice compared to control (24M). Furthermore, a significant 23% increase in microglia was described for GFAP‐IL6 (24M) compared to the GFAP‐IL6 (12M) mice. A significant 28% and 38% decrease in microglial 3D surface area, and volume respectively were observed between WT and GFAP‐IL (12M) mice, as well as 26% and 34% decrease respectively between WT (12M) and (24M), resembling reactive microglial morphology. Meanwhile, cholinergic cell number displayed a significant 31% decrease in GFAP‐IL6 (12M) mice compared to WT (12M). While a significant 30% decrease was displayed in GFAP‐IL6 (24M) mice compared to WT (24M) mice. There was a tendency for the cholinergic cell number to decrease with ageing among control and GFAP‐IL6 cohorts. Cholinergic cell morphology displayed significant 58% and 67% reduction in the 3D dendritic field surface area, and volume respectively between WT (12M) and GFAP‐IL (12M) mice, as well as 41% and 46% decrease respectively between WT (12M) and (24M), displaying patterns like neuronal degeneration.ConclusionThese findings demonstrate a significant impact of both aging and chronic glial activation alone on cholinergic cell number and morphology in the MS, resembling the cholinergic cell loss in AD, which can exacerbate throughout ageing leading to neurodegenerative impairments.

Effect of endogenetic dissolved organic matter on tetracycline adsorption by biochar.

The endogenetic biochar-derived dissolved organic matter (BDOM) might interact with pollutants in the environment. In this study, tetracycline (TC) was selected as the representative pollutant, and corn straw biochar (pyrolyzed at 300 °C) was used as the adsorbent. Through batch experiments and microscopic characterization, the releasing kinetics of BDOM and its effect on TC adsorption on biochar were investigated. The results showed that BDOM with weaker aromaticity and higher molecular weight was preferentially released. BDOM release led to the decrease of specific surface area (from 4.02 to 1.83 m2/g), mesopore number, and aromaticity of biochar (H/C increased from 0.80 to 0.91) and consequently weakened the pore filling of TC on biochar, hydrophobic interaction, and π-π EDA (electron donor receptor) interaction between biochar and TC. In addition, the released BDOM could form a complex with TC in solution to prevent TC adsorption on biochar. Overall, the change in the structural properties of biochar caused by BDOM release had a greater impact on the inhibition of TC adsorption than that of BDOM and TC complexation in this study. Through EEM-PRARFAC, BDOM contained about 63% humic acid-like fluorescent component and 37% tryptophan-like fluorescent component; the former (logKb values were 7.31 and 6.48, respectively) had a stronger binding strength with TC than the latter (logKb was 6.45). The findings of this study could provide some useful evidence for the removal of organic pollutants in soil and water environments and biochar application in pollution remediation.