Weak Retention Research Articles

Engineering injectable bioadhesives with sealing and anti-fouling properties for postoperative anti-adhesion

Postoperative adhesion is a common complication that follows various types of surgeries, causing patients suffering and increasing healthcare costs. Current anti-adhesion barriers fail to provide satisfactory therapeutic outcomes mainly due to their weak retention, inability to prevent fluid leakage, and potential foreign body reactions. In the present study, we fabricated a serine-modified bioadhesive (SESAgel) with improved sealing and anti-fouling properties for postoperative adhesion prevention. The resulting SESAgel exhibited good injectability and in-situ adhesion ability, forming a stable membranous anti-adhesion barrier on the wound surface. Innovatively, it possessed efficient sealing properties, effectively stopping the leakage of tissue fluid and blood, which triggers tissue adhesion formation in the early stage. On this basis, the anti-fouling property derived from the serine in this physical barrier can further prevent the accumulation of inflammatory cells and foreign body reactions, thereby minimizing tissue adhesion. Two animal models were used to demonstrate that SESAgel effectively inhibited postoperative adhesion in different surgeries. With its natural design and good biocompatibility, SESAgel is a promising anti-adhesion biomaterial for clinical translation and practice.

Reverse phase, ion exchange, HILIC and mix-mode chromatography for the determination of metformin and evogliptin in human plasma and pharmaceutical formulations

Separation and quantification of highly polar metformin (MTF) alone or in combination with dipeptidyl peptidase-4 inhibitors, such as evogliptin (EVG), sitagliptin, saxagliptin, vildagliptin, linagliptin and teneligliptin, specifically from human plasma and pharmaceutical products is still difficult in mostly preferred ODS based RP-HPLC techniques. Since, owing to weak retention of MTF in ODS, it elutes together with the biological fluid components and drug excipients. Therefore, in this study, alternative to ODS based RP-HPLC, comparatively less known analytical techniques like strong cation exchange chromatography (SCX-3), hydrophilic interaction liquid chromatography (HILIC) and mix-mode chromatography (MMC) were comprehensively evaluated for their potentials and limitations in simultaneous quantification of newly approved EVG and MTF combination (Valera-M). In results, prolonged application of SCX-3, exhibits irreproducible and irreversible retention of MTF and EVG. While in HILIC with Cyano column, excessive acetonitrile as eluent developed the precipitation of MTF and column back pressure. Comparatively, the Acclaimed® mix-mode HILIC-1, demonstrated much promising and reproducible results for MTF and EVG separation and importantly, it can be used either reverse phase or HILIC mode. Considering the overall benefits of Acclaimed® mix-mode HILIC-1, it was used in estimation of MTF and EVG from human plasma and pharmaceutical formulations.

Comparison of the effectiveness of immobilization of cations on the surface of a polymer carrier in order to use the resulting composition in the technology of bakery products

In regions with an identified imbalance of nutrients necessary for life, the development and optimization of recipes for flour products is relevant. Basically, enrichment is carried out by adding a solution of the necessary component to a dish or enriching food components at the growth stage. In order to increase the safety of the introduced phase, the fixation was carried out by physical immobilization on the surface of biopolymer spouts. The elements were magnesium, zinc and nickel. Natural sorbents chitosan and cellulose were chosen as carriers. The solutions of the compounds of the elements were mixed with the carriers for 30 minutes, after which they were infused for 24 hours. The resulting composition was filtered out and based on the difference in the concentration of the initial solutions with respect to the filtrate, a conclusion was formed about the effectiveness of the immobilization process. As a result of the determination, the successful fixation of a zinc and nickel compound on the chitosan surface was established. Cellulose demonstrated weak retention of immobilized components. The reason for this is the weak mechanical strength of the selected conditions. Based on the results of the study, conclusions were formed about the effectiveness of the selected carriers.

Performance of Self-healing microgel incorporating Nano-Silica as plugging material for drilling fluid

Lost circulation severely threatens the safety and efficiency of oil drilling operations, especially at high temperatures. Accordingly, many plugging materials have also been studied and applied, such as inert bridge materials, inorganic cement, and organic gel. However, these materials have certain limitations. For example, inert materials are difficult to form dense plugging slugs and have weak cementing strength with the formation; cement slurry is easily diluted and dispersed in the formation, and the waiting process required for cement greatly increases the non-productive time. Comparatively, polymer gel is widely used in lost circulation control because of its good deformability and water absorption capacity. However, conventional polymer gel usually has low mechanical strength and weak retention capacity in the leakage layer. In addition, there is a lack of sufficient interaction between plugging materials and the formation, which makes it difficult to form a highly dense plugging layer. Under high pressure conditions, a large amount of leakage still occurs, and even repeated leakage occurs under frequent pressure fluctuations, resulting in plugging failure. Herein, we synthesized zwitterionic polymer/nano-silica microgels (P(MPTC-co-NaSS)@SiO2) with dynamic crosslinking ability through a facile one-step reversed phase emulsion polymerization. They exhibited spherical particles of narrow size distribution around 40 μm in aqueous dispersion. The strong hydrogen bonds, electrostatic interaction and cation-π endowed microgels excellent self-healing ability, strong mechanical strength and sufficient high-temperature stability. Although high temperature and salinity decreased the particle size and rheological property as well as the particle quantity, P(MPTC-co-NaSS)@SiO2 microgels maintained fairly constant rheological properties and achieved significant plugging performance in the temperature range of 70–––150 °C and simultaneously with a salinity tolerance up to 7.5 wt% NaCl contamination. P(MPTC-co-NaSS)@SiO2 microgels were well dispersed in water-based drilling fluid (WBDF) and generated a bulk gel when concentrated in pores and cracks, which was applicable to plugging drilling fluids. A conventional WBDF with remarkable plugging property was formulated by facilely supplementing with P(MPTC-co-NaSS)@SiO2, which has a great prospect for applications in oil field. This study builds a bridge between fundamental research on microgels and the applications of soft particles as plugging materials in oil industry.

Surface-bubble-modulated liquid chromatography: an experimental strategy for identification of molecular processes of solute retention in reversed-phase separation systems.

Molecular level understanding of the chemistry at the aqueous/hydrophobe interface is crucial to separation processes in aqueous media, such as reversed-phase liquid chromatography (RPLC) and solid-phase extraction (SPE). Despite significant advances in our knowledge of the solute retention mechanism in these reversed-phase systems, direct observation of the behavior of molecules and ions at the interface in reversed-phase systems still remains a major challenge and experimental probing techniques that provide the spatial information of the distribution of molecules and ions are required. This review addresses surface-bubble-modulated liquid chromatography (SBMLC), which has a stationary gas phase in a column packed with hydrophobic porous materials and enables one to observe the molecular distribution in the heterogeneous reversed-phase systems consisting of the bulk liquid phase, the interfacial liquid layer, and the hydrophobic materials. The distribution coefficients of organic compounds referring to their accumulations onto the interface of alkyl- and phenyl-hexyl-bonded silica particles exposed to water or acetonitrile-water and into the bonded layers from the bulk liquid phase are determined by SBMLC. The experimental data obtained by SBMLC show that the water/hydrophobe interface exhibits an accumulation selectivity for organic compounds, which is quite different from that of the interior of the bonded chain layer, and the overall separation selectivity of the reversed-phase systems is determined by the relative sizes of the aqueous/hydrophobe interface and the hydrophobe. The solvent composition and the thickness of the interfacial liquid layer formed on octadecyl-bonded (C18) silica surfaces are also estimated from the bulk liquid phase volume determined by the ion partition method employing small inorganic ions as probes. It is clarified that various hydrophilic organic compounds as well as inorganic ions recognize the interfacial liquid layer formed on the C18-bonded silica surfaces as being different from the bulk liquid phase. The behavior of some solute compounds exhibiting substantially weak retention in RPLC or the so-called negative adsorption, such as urea, sugars, and inorganic ions, can rationally be interpreted with a partition between the bulk liquid phase and the interfacial liquid layer. The spatial distribution of solute molecules and the structural properties of the solvent layer on the C18-bonded layer determined by the liquid chromatographic methods are discussed in comparison to the results obtained by other research groups using molecular simulation methods.

Retention effect and mode of capillary zone on the migration process of LNAPL pollutants based on experimental exploration

Two-dimensional sand tank experiments were designed to investigate the retention process of the capillary zone during the migration of light non-aqueous phase liquid (LNAPL) pollutants. The fine sand and silt media experiments simulated the LNAPL migration process given a shallow point source leakage scenario. The results indicate that the LNAPL was retained in the capillary zone. A retention factor, based on the ratio of the change in the vertical migration velocity of the LNAPL front with time, was proposed to quantitatively characterize the retention effect. The retention factor and time satisfied the function of σ=A×exp(−kt). And the retention factor increased gradually with time, indicating the enhanced retention effect of capillary zone on the vertical migration of LNAPL. The concentration change rate was then used to investigate the LANPL redistribution process, which had a relationship with time of νc=B×ln(t)+C. The capillary zone could be divided from top to bottom into a weak retention zone (B > 0, vc < 0), a strong retention zone (B < 0), and a barrier zone (B > 0, vc > 0). The retention effect of capillary zone on LNAPL migration gradually strengthened during the vertical migration of LNAPL. In addition, the coefficient B had a relationship with the environmental factors (i.e., EC, pH, and ORP) of B=a×sin(b×α×β×γ)c and the fitting coefficient R2 of the function was above 0.913 for both media, indicating a strong correlation between the LNAPL redistribution process and the key environmental factors.

Talent Management: The Game Changer for Work Engagement of Non-Teaching Workforce at Kyambogo University, Uganda

The challenge in public universities in Uganda is that university non-teaching staff are disengaged and take their jobs for granted, hence never make an effort to serve to the satisfaction of students and other stakeholders. This study examined whether talent management strategies employed by the universities were a game changer for work engagement of the non-teaching workforce in public universities. Specifically, the study tested whether talent management in terms of talent attraction, talent development and talent retention had a relationship with work engagement of the non-teaching workforce in public universities. The study employed a correlational research design on a sample of 201 non-teaching staff. Data was collected using a questionnaire survey. The findings revealed that talent attraction and talent development had a positive significant relationship with work engagement of the non-teaching workforce. However, talent attraction had a negative and insignificant relationship with work engagement of the non-teaching workforce. It was concluded that talent attraction strategies in terms of selective recruitment and selection, and talent development in the form of performance appraisal, training and promotion are game changers for work engagement of the non-teaching staff. However, weak retention strategies hamper employee engagement. The study recommends that managers of universities should implement game-changing talent attraction strategies and talent development practices to enhance work engagement of the non-teaching workforce. It is also recommended that university managers should strengthen talent retention strategies to promote work engagement of the non-teaching workforce.

Arsenic and cadmium leaching in co-contaminated agronomic soil and the influence of high rainfall and amendments

Arsenic (As) and cadmium (Cd) co-contaminate agricultural systems worldwide and threaten water resources, food security and human health. This column leaching study examined As and Cd mobility in an acidic sandy loam Alfisol soil collected from the dry zone of Sri Lankafor four co-contaminant concentration combinations (spiked and 1 year aged As at 20 & 100 mg kg−1 with co-added Cd at 3 & 20 mg kg−1) i, and under the influence of high rainfall (RF), phosphorus fertilizer (P) and lime amendments. In almost all treatments a synergistic co-contaminant adsorption effect was evident which reduced leaching of both elements, significantly in the higher spiked soil concentration treatments. The magnitude of leaching decrease varied with treatment but was greater for As due to its weaker retention in the soil. The co-sorbing effects, evident even under RF, were attributed to electrostatic sorption interactions, the formation of ternary bridging complexes and surface precipitation at higher concentrations. Liming significantly retarded mobilisation of both elements in all treatments, whereas P enhanced As leaching but suppressed Cd leaching, and both amendments moderated co-contaminant effects. An antagonistic effect of Cd on As sorption was evident in two treatments which showed increased As leaching with added Cd: the RF low spike concentration treatment, accredited to washout of stable As–Cd soluble complexes; the P high concentration treatment considered due to P disruption of As–Cd bridging complexes. This work is important for effective risk mitigation in these widely occurring co-contaminated agronomic systems, and demonstrates a strong system effect on synergistic or antagonistic co-contaminant interactions.

Nurse Managers’ Views of Measures to Improve Nurse Retention at a Selected Hospital in KwaZulu-Natal, South Africa

The massive global nursing shortage in health care settings increases nurses’ workloads and complicates workflow. Health care personnel employed in public hospitals generally work under appalling working conditions. As disease burdens increase, high vacancy rates and workloads increase, thereby producing chronic staff shortages. Nursing managers can commit to their role in designing and maintaining strategies for effective management of human resources for health. The purpose of the current study was to explore and determine the views of nurse managers regarding staff turnover and retention, and make recommendations to improve nurse retention. An exploratory, descriptive, qualitative study was conducted using purposive sampling to select nurse managers at a selected hospital in KwaZulu-Natal (KZN), South Africa. Focus group discussions (FGDs) were conducted with 18 nurse managers from the hospital. The FGDs were transcribed verbatim and analysed using thematic analysis from which four themes were generated, namely: staff turnover challenges; current retention strategies; measures to improve retention; and strategies to strengthen management. The participants believed that excessive workload and the lack of human resources compromised the quality and efficiency of patient care. Retention strategies recommended included: improving benefits and rewards; increasing staff development; developing nursing support systems; maintaining adequate resources for optimal functioning; using emerging technology applications; and strengthening leadership roles. The current study revealed weak retention measures in the selected hospital and recommended new and improved retention measures to retain nurses and curtail turnover.

Characterization of the Interfacial Liquid Layer Formed on Hydrophobic Packing Material Surfaces by Liquid Chromatographic Analysis of the Distribution of Ions and Molecules.

We determine the bulk liquid phase volumes in octadecyl-bonded silica (C18 silica) columns equilibrated with acetonitrile–water and methanol–water (0–19%(v/v)) binary mixed solvents by a liquid chromatographic method with inorganic ions used as probes. The solvent composition and the thickness of the interfacial liquid layer formed on the C18-bonded silica surface are then determined from the bulk liquid phase volume, the total liquid phase volume, the surface area of the C18 silica packing material, and the retention volumes of the isotopically labeled eluent components for the columns. We used two C18 silica packing materials having identical bonding structures but different pore sizes and surface areas. Our results show that various hydrophilic organic compounds as well as inorganic ions recognize the interfacial liquid layer as being different from the bulk phase. The behavior of the solute compounds exhibiting substantially weak retention in reversed-phase liquid chromatography or the so-called negative adsorption, such as urea, sugars, and inorganic ions, can rationally be interpreted with a partition between the bulk liquid phase and the interfacial solvation liquid layer. The structural properties of the solvent layer on the C18-bonded layer determined by liquid chromatography are consistent with the molecular dynamics simulation results that have been obtained by other researchers.

Synthesis of Metal-Loaded Carboxylated Biopolymers with Antibacterial Activity through Metal Subnanoparticle Incorporation.

Carboxymethyl starch (CMS) and carboxymethyl cellulose (CMC) loaded by highly dispersed metal subnanoparticles (MSNPs) showed antibacterial activity against E. coli and B. subtilis strains. Copper and silver were found to act in both cationic and zero-valence forms. The antibacterial activity depends on the metal species content but only up to a certain level. Silver cation (Ag+) showed higher antibacterial activity as compared to Ag0, which was, however, more effective than Cu0, due to weaker retention. The number of carboxyl groups of the biopolymers was found to govern the material dispersion in aqueous media, the metal retention strength and dispersion in the host-matrices. Cation and metal retention in both biopolymers was found to involve interactions with the oxygen atoms of both hydroxyl and carboxyl groups. There exists a ternary interdependence between the Zeta potential (ZP), pH induced by the biocidal agent and its particle size (PS). This interdependence is a key factor in the exchange processes with the surrounding species, including bacteria. Clay mineral incorporation was found to mitigate material dispersion, due to detrimental competitive clay:polymer interaction. This knowledge advancement opens promising prospects for manufacturing metal-loaded materials for biomedical applications.

Indoor synthesis of carbon quantum dots and its potential applications study as tracers in oilfields

Feasibility of carbon quantum dots as tracers in petroleum industry was explored in this study to provide diversified options for reservoir evaluation. A kind of water-soluble fluorescent carbon quantum dots (CA-CQDs) with high fluorescence quantum yield and an average particle size of ca. 5.6 nm was successfully prepared with citric acid as carbon source and ethylenediamine as nitrogen source by controlling hydrothermal temperature and time. Fluorescence test results demonstrated that CA-CQDs were easy to sample and analyse and present outstanding fluorescence performance at 10−6 g L−1. The stability, adsorption, compatibility and fluidity of CA-CQDs were comprehensively evaluated. Results showed that optical properties of CA-CQDs present excellent stability because they minimally changed under different temperatures, salt solutions and pH conditions. Adsorption effect of different minerals on CA-CQDs was small, and concentration retention rate was stable at above 90% after 5 days of adsorption. CA-CQDs showed satisfactory compatibility with formation water samples, and concentration deviation was maintained within 2%. It was convenient for real-time monitoring and analysis because CA-CQDs presented evident breakthrough–elution process with strong migration capacity but weak retention and adsorption capacities when flowing in the pipeline. The results of this study proved that CA-CQDs demonstrated high application potential as tracers in oilfields.

Simultaneous determination of indole metabolites of tryptophan in rat feces by chemical labeling assisted liquid chromatography-tandem mass spectrometry

As the connecting part of diet and host physiology, intestinal microbes can convert the ingested diet into a huge number of physiologically active small molecules. Indole metabolites of tryptophan are precursors or signal molecules for many biologically active substances, which are involved in serotonin and microbial catabolism pathways. To understand the influence of tryptophan metabolism in the intestinal environment on the neurological and immune systems at the molecular level, it is important to establish a high-coverage analytical method to comprehensively analyze the metabolites involved in tryptophan metabolism. However, due to a small molecular weight and poor response during mass spectrometry analysis, as well as weak retention on the reversed-phase chromatography, determination of indole metabolites of tryptophan is challenging. Here, we proposed a method for the simultaneous determination of 20 indole metabolites of tryptophan in a single run on reversed-phase chromatography by chemical labeling coupled to liquid chromatography-tandem mass spectrometry analysis. 4-(Dimethylamino)benzaldehyde (DMAB) was used for the labeling of indole metabolites of tryptophan, which could significantly improve the detection sensitivities and retention of these metabolites on reversed-phase chromatography. With the developed method, we realized the sensitive detection and comprehensive analysis of 15 endogenous indole metabolites of tryptophan in rat feces samples with functional dyspepsia intervention by acupuncture. The developed method offers a useful tool for studying tryptophan metabolism-related diseases.

In situphotoinitiated fabrication of phosphorylcholine-functionalized polyhedral oligomeric silsesquioxane hybrid monolithic column for mixed-mode capillary electrochromatography

A phosphorylcholine-functionalized POSS hybrid monolithic column was synthesizedviaUV curing. It exhibits hydrophilic interaction and weak cation exchange chromatography retention mechanism for the separation of typical polar and charged compounds.

Fabrication of diamond enhanced WC-Ni composites by spark plasma sintering

Wear resistance of the rock drill bit is one of the important factors affecting drilling efficiency and exploration cost. Hence, the development of tool materials with high wear resistance has been widely concerned by researchers. The composites of cemented carbides and Ti-coated diamond (Ti/Dia) were successfully prepared by spark plasma sintering with excellent wear resistance. The characterization of microstructure and phase composition revealed that diamond particles distributed homogeneously without obviously graphitization. With 2–6 wt% Ti/Dia, the relative density, hardness and flexural strength of the composites were all improved. However, with the further increase in Ti/Dia content, the relative density and flexural strength sharply decreased. The composites with 2 wt% Ti/Dia shown the best wear resistance and the wear rate was reduced by 50 times compared with that of the sample without diamond addition. The diamond plays an important role in the rock cutting and grinding for the sample with 2 wt% Ti/Dia. However, for the samples with 18 wt% Ti/Dia, the cutting edge is easy to fracture and the diamond is more likely to pull-out whole because of the weak retention ability of the matrix to diamond.

Selective retention of particulate matter by nine plant species in central Shanxi Province, China.

Plant leaves can accumulate particulate matter (PM) from the air, thus mitigating air pollution. Nine plant species from the central part of Shanxi Province, China, were investigated to characterize differences in their PM retention capacity and the grain sizes of the collected PM. Styphnolobium japonicum, Syringa oblata, and Cerasus serrulata demonstrated strong retention capacity for PM particles of diverse size fractions. Philadelphus incanus, Viburnum opulus, and Yulania biondii had relatively weak retention capacity for overall and fine PM. Generally, species with smaller leaves and roughness surfaces, waxy leaves, or leaves with hair had strong PM retention capacity. Leaves with suitable groove widths better retained fine PM. Foliar dust observed on leaves presented multimodal distribution curves, including bimodal, trimodal, and four-peak distributions, which differed from the trimodal distribution of natural dustfall. The different PM retention capacities of the nine investigated species and the differing grain sizes between foliar dust and atmospheric dustfall indicated that plant leaves could selectively retain PM. The results of this study provide a scientific basis for the use of the plant to mitigate particulate air pollution.

Determination of Cytisine and N-Methylcytisine from Selected Plant Extracts by High-Performance Liquid Chromatography and Comparison of Their Cytotoxic Activity

Quinolizidine alkaloids exhibit various forms of biological activity. A lot of them were found in the Leguminosae family, including Laburnum and Genista. The aim of the study was the optimization of a chromatographic system for the analysis of cytisine and N-methylcytisine in various plant extracts as well as an investigation of the cytotoxic activities of selected alkaloids and plant extracts obtained from Laburnum anagyroides, Laburnum anagyroides L. quercifolium, Laburnum alpinum, Laburnum watereri, Genista germanica, and Genista tinctoria against various cancer cell lines. The determination of investigated compounds was performed by High Performance Liquid Chromatography with Diode Array Detection (HPLC-DAD), while High Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight–Mass Spectrometry (HPLC-QTOF-MS) was applied for the qualitative analysis of plant extracts. The retention, separation selectivity, peaks shape, and systems efficiency obtained for cytisine and N-methylcytisine in different chromatographic systems were compared. The application of columns with alkylbonded and phenyl stationary phases led to a very weak retention of cytisine and N-methylcytisine, even when the mobile phases containing only 5% of organic modifiers were used. The strongest retention was observed when hydrophilic interaction chromatography (HILIC) or especially when ion exchange chromatography (IEC) were applied. The most optimal system in terms of alkaloid retention, peak shape, and system efficiency containing an strong cation exchange (SCX) stationary phase and a mobile phase consisted of 25% acetonitrile and formic buffer at pH 4.0 was applied for investigating alkaloids analysis in plant extracts. Cytotoxic properties of the investigated plant extracts as well as cytisine and N-methylcytisine were examined using human tongue squamous carcinoma cells (SCC-25), human pharyngeal squamous carcinoma cells (FaDu), human triple-negative breast adenocarcinoma cell line (MDA-MB-231), and human breast adenocarcinoma cell line (MCF-7). The highest cytotoxic activity against FaDu, MCF-7, and MDA-MB cancer cell lines was observed after applying the Genista germanica leaves extract. In contrast, the highest cytotoxic activity against SCC-25 cell line was obtained after treating with the seed extract of Laburnum watereri. The investigated plant extracts exhibit significant cytotoxicity against the tested human cancer cell lines and seem to be promising for further research on its anticancer activity.

Texture formation in face-centered cubic high-entropy alloys

High-entropy alloys (HEAs) have attracted much attention both from academia and industry mainly because of their particular properties giving hope for future structural and functional applications. As texture leads to an anisotropy of the properties, it is the aim of this paper to present a detailed review on texture evolution in face-centered cubic (FCC) HEAs during thermo-mechanical processing. Key results from published articles provide an up-to-date information regarding texture formation in these HEAs during tension, compression, rolling and shear deformation. The characteristics of deformation texture is similar to that of other conventional low/medium stacking fault energy (SFE) alloys such as high manganese steels and Ni-60wt%Co alloys. However, the overall texture intensity is quite low even after heavy deformation. The recrystallization textures of FCC HEAs show a weak retention of brass-type deformation texture components and texture randomization. New orientations during recrystallization mostly have first order twin relationship with the deformation texture components. Most of the first order twin orientations are retained during grain growth indicating the absence of preferential growth of certain crystallographic orientations. Finally, similarities and differences in texture evolution to other conventional low/medium SFE alloys are discussed.

Removal of biogenic amines from hydroalcoholic solutions by functionalized silica

The structure and the cation-exchange functional groups of hybrid silica materials were evaluated for the effective detoxification of hydroalcoholic solutions containing eight toxic biogenic amines (BA) usually found in fermented beverages. Results show the effectiveness of the removal is related to the number of amino functions in the extracted molecule, retention by the solid being more effective in the case of multiple amino groups, since retention is stabilized through interaction with the material surface at several points. BA with one amino function (isoamylamine, tyramine, β-phenylethylamine), in general, showed a weak retention by the solids. For BA with more than two amine groups (spermine, spermidine), the removal rate was close to 100% for all studied materials. For histamine, cadaverine and putrescine, the removal percentages were higher with a lamellar structured sulfonic acid functionalized material and with bifunctional materials (SBA-15 type and macroporous) containing sulfonic/phosphonic acid groups obtained by co-condensation sol-gel route.

Improved Non-local Means Algorithm for Image Denosing

In order to solve the problem that Non-local means method (NLM) results in a weaker retention and noise immunity, an improved non-local means (INLM) is proposed. This paper introduces bilateral structure tensor combined with the spatial distance and the gradient distance to weight the structure tensor matrix. It has stronger noise immunity and can extract the texture structure more accurately. Mahalanobis distance is applied as a measure of the similarity of image pixels to suppress noise interference. Analyses and simulation results prove the validity of the proposed algorithm.