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A significant amount of chlorine, and alkali and alkaline earth metal (AAEM) in food waste has been a major limitation to the utilization of food waste as fuel. The present study aims to investigate the behavior of chlorine and AAEM in food waste biochar during pyrolysis, demineralization, and combustion. Food waste compost (FWC) and food waste feedstock (FWF) were selected as raw materials. Three different pyrolysis temperatures from 300 to 500 °C and two demineralization processes, water and CO2–saturated water, were employed. As the pyrolysis temperature increased, crystallized salt was removed through demineralization, which further increased the heating value. Effective removal of chlorine was demonstrated in both demineralization methods. During demineralization, re-adsorption of Ca on food waste biochar occurred, which was alleviated by CO2-water demineralization. The total amounts of volatilized Cl and AAEM after CO2–water demineralization were reduced by 74.79–99.38% for FWF and 98.34–99.9% for FWC compared to raw biochar. Furthermore, slagging and fouling potentials for all food waste biochar samples were estimated using various indices. The proposed behavior of Cl and AAEM in food waste biochar during various fabrication conditions provides insight into how food waste biochar can be applied in thermos-electric power plant for co-firing with coal.

Objectives: This study aims to evaluate the effectiveness of topical fluoride application and diode laser-irradiation on the hardness of demineralized enamel and to evaluate the esthetic improvement of the white spot lesions (WSLs) using a visual analog scale (VAS). Materials and Methods: Artificial WSLs (3x3 mm) were created on the enamel surface of 45 human third molars. The teeth were randomly assigned into three groups (n = 15): group A, fluoride only; group B, combined therapy of fluoride and diode laser; and group C, control. Vicker’s hardness number (VHN) was measured at baseline, after demineralization and after treatment. To evaluate the esthetic improvement after treatment, 14 raters evaluated each group’s photographs using a 100-millimeter VAS. A one-way ANOVA or Brown-Forsythe and Games-Howell post hoc procedure were performed for statistical analysis. The level of significance was set at α = 0.05 for all tests. Results: Group A mean VHN was significantly higher than groups B and C, and group B was significantly higher than group C (P

OBJECTIVES: To evaluate the effects of different polyphenols and solvents on dentin collagen’s crosslinking interactions and biostabilization against MMPs and collagenase degradation. METHODS: Two polyphenols [proanthocyanidin (PA) and quercetin (QC)] with different water solubility were prepared as treatment solutions using ethanol (EtOH) or dimethyl sulfoxide (DMSO) as solvents. 6-um-thick dentin films were microtomed from dentin slabs of third molars. Following demineralization, films or slabs were subject to 60-s treatment (PA or QC) or no treatment (control) with subsequent extended-rinse with original solvent (EtOH or DMSO) or distilled water (DW). Collagen crosslinking interactions were assessed by FTIR. Biostability was assessed through endogenous MMPs activity via confocal laser scanning microscopy, and exogenous collagenase degradation via weight loss, hydroxyproline release and SEM. Finally, direct collagenase inactivation was also evaluated. Data were analyzed by three-way ANOVA and post-hoc tests (α=0.05%). RESULTS: Distinct effects of two polyphenols and solvents on collagen crosslinking and biostabilization were observed. Higher crosslinking and biostability efficacy occurred with PA than QC (p < 0.001) that demonstrated negligible collagen interactions. With DMSO solvent, efficacy results were significantly reduced with both polyphenols (p < 0.05). DMSO-rinse further weakened interactions of PA with collagen, diminishing biostability (p < 0.05). Low biostability was detected with QC and DW-rinse, suggesting direct enzymatic inhibition due to physical presence in collagen. SIGNIFICANCE: Collagen crosslinking interactions and biostability depend on polyphenol chemical characteristics. Treatment-solution solvents may affect interactions between polyphenols and collagen, specifically, DMSO showed detrimental effects on collagen crosslinking and biostability and should be used with caution.

Background: The denture-base acrylic resins used by partially edentulous patients can cause local demineralization of teeth. Alkali ions released from the bioactive materials that were added to acrylic resins can increase the pH of the oral environment and slow down the demineralization process. Aim of the study: This study aimed to create a new denture-base acrylic resin that can release ions. Materials and methods: A total of 222 samples with different fillers (calcium hydrogen phosphate, hydroxyapatite, two kinds of bioactive glasses, and a product obtained by reaction between bioactive glass formed from glass ionomer cement and polyacrylic acid) were prepared for the study. All the materials were tested for mechanical properties and their use as phosphate donors for 3 weeks. The measurements were presented as mean ± SD error of the mean. Data were analyzed by two-way analysis of variance, with a p-value of

Purpose Sweptsource optical coherence tomography (SS-OCT) permits cross-sectional observation of surface/subsurface characteristics of enamel including early carious lesions (ECL) or remineralization non-invasively.This study aimed to visually compare the cross-sectional remineralizing efficacy of various agents on ICDAS-II scores-1&2 by using SS-OCT and histology. Methods Baseline SS-OCT (grey-scale/false-colour) and histology was performed on the randomly selected two samples with scores-1&2. Four remineralizing agents [fluoride-varnish (FV), CPP-ACP, nanohydroxy-paste (NHP) and silver-diamine-fluoride (SDF)]were evaluated for 2-or 6-weeks post-remineralization using SS-OCT and histology. Results Score-1&2 baseline SS-OCT images showed a linear-shaped demineralization with dentino-enamel junction (DEJ) visible; and bowl-shaped demineralization with DEJ invisible respectively. Remineralizing agents were assessed on the basis of their ability to remineralize the surface, subsurface and made visualize the DEJ in score-2. SS-OCT showed an outer growth layer in post-remineralization score-1, 2-weeks samples with FV and NHP. All the agents showed progressive subsurface remineralization in 6 weeks. Active lesions showed rapid uptake of minerals on surface. Subsurface mineralization in pigmented score-2 matched sound enamel with NHP and SDF. Surface remineralization was comparable in FV and SDF followed by NHP. SDF demonstrated deeper subsurface remineralization followed by NHP and CPP-ACP. Conclusion SS-OCT images correlated to histology. SS-OCT could monitor surface/subsurface in-situde/remineralization activity non-invasively.

To evaluate the differences in the pullout strength and displacement of pedicle screws in cadaveric thoracolumbar vertebrae with or without artificial demineralization.Five human lumbar and five thoracic vertebrae from one cadaver were divided into two hemivertebrae. The left-side specimens were included in the simulated osteopenic model group and the right-side bones in a control group. In the model group, we immersed each specimen in HCl (1 N) solution for 40 minutes. We measured bone mineral density (BMD) using dual-energy X-ray absorptiometry and quantitative computerized tomography. We inserted polyaxial pedicle screws into the 20 pedicles of the cadaveric lumbar and thoracic spine after measuring the BMD of the 2 hemivertebrae of each specimen. We measured the pullout strength and displacement of the screws before failure in each specimen using an Instron system.The average pullout strength of the simulated osteopenic model group was 76% that of the control group. In the control and model groups, the pullout strength was 1678.87±358.96 N and 1283.83±341.97 N, respectively, and the displacement was 2.07±0.34 mm and 2.65±0.50 mm, respectively (p.05). We detected positive correlations between pullout strength and BMD in the control group and observed a negative correlation between displacement and BMD in the model group.By providing an anatomically symmetric counterpart, the human cadaveric model with or without demineralization can be used as a test bed for pullout tests of the spine. In the simulated osteopenic model group, pullout strength was significantly decreased compared with the untreated control group.Decreased bone mineral density may significantly reduce the pullout strength of a pedicle screw, even though the range is osteopenic rather than osoteoporotic.

Objectives The purpose of the study was to evaluate the integrity of dentine type I collagen after self-etching (SE) treatments with strong and mild universal adhesives. Methods Coronal dentine specimens (n = 10/product) were imaged by optical microscopy and analyzed by ATR-FTIR spectroscopy before and after treatment with 32% phosphoric acid gel (PA-negative control), 17% neutral EDTA (ED-positive control) conditioners and Adhese Universal (AD), Clearfil Universal Bond Quick (CQ), G-Premio Bond (GP), Prelude One (PR) and Scotchbond Universal (SB) adhesives. From the spectroscopic analysis the following parameters were determined: a) Extent of dentine demineralization (DM%) and b) percentage area of the Amide I curve-fitted components of β-turns, 310-helix/β-turns, α-helix, random coils, β-sheets and collagen maturation (R) index. Statistical analysis was performed by one-way ANOVA (DM%), paired t-test/Wilcoxon test (Amide I components) and Spearman correlation coefficient (DM% vs Amide I components) at an a = 0.05 level. Results PA, ED and GP removed the smear-layer and opened tubule orifices, whereas all other treatments removed only the intratubular smear-layer fraction. The ranking of the statistically significant differences in DM% was PA > GP > ED > AD, SB, CQ, PR, with AD being significantly different from PR. Regarding the Amide I components, PA demonstrated a significant reduction in β-turns, α-helices and an increase in β-sheets, GP a reduction in β-turns, AD an increase in β-turns and random coils, and CQ an increase in β-turns. PR, SB and ED showed insignificant differences in all the Amide I components. Significant correlations were found between DM%-random coils and DM%-R. Significance The universal adhesives used in the SE mode induced none to minimal changes in dentine collagen structure, without evidence of the destabilization pattern observed after conventional phosphoric acid treatments.

Dental caries is a dynamic, preventable, reversible, complex biofilm-mediated, multifactorial disease that involves a series of demineralization/neutrality/remineralization of dental hard tissue in primary and permanent dentition. An imbalance in the continuum with a net demineralization over time results in the initiation of caries lesions. Visual inspection and intraoral radiographs are vital in caries detection, although they are of suboptimal sensitivity for early caries lesions. Shifting toward a conservative, noninvasive approach to caries management has resulted in the development of innovative-sensitive technologies. These newer techniques may serve as adjunct for the dental practitioner in detecting earliest changes in tooth structure.

Objective To evaluate preventive effects of S-PRG-filled resin-composites on surrounding tooth demineralization and interfacial bacterial penetration. Methods Cavities were prepared on enamel or dentin blocks and treated by BeautiBond Universal (Shofu) and filled by resin-composites containing S-PRG filler (Shofu) at 0 wt% (P0, control), 10 wt% (P10), 30 wt% (P30), 50 wt% (P50) or 70 wt% (P70). The specimens were demineralized by Streptococcus mutans biofilms for 12 days. Wall lesion depth (WL-depth) and outer lesion depth (OL-depth) were measured from fluorescence microscopy. Interfacial bacterial penetration area (BPA) was evaluated from confocal laser scanning microscopy. Wall lesion hardness (WL-hardness) and outer lesion hardness (OL-hardness) were measured with a Vickers microhardness tester. Elemental analysis of resins and surrounding lesions was conducted by scanning electron microscopy and energy dispersive X-ray spectrometry. Results Resin-composites in P70 contained significantly more F, Na and Al than that in P0 and P10. P70, P50 and P30 showed significantly lower WL-depth than P0. P70 showed significantly lower OL-depth, fewer Ca and P loss in lesions than P0. P70 showed significantly higher WL-hardness and OL-hardness in dentin specimens than P0. Enamel margins had a higher gap frequency than dentin margins. However, BPA did not show significant differences among the groups. Significance Resin-composites containing S-PRG fillers at ≥30 wt% can inhibit wall lesions and that at 70 wt% can further decrease outer lesions, reduce Ca and P loss in lesions and increase surrounding dentin hardness. However, S-PRG-filled resin-composites does not inhibit interfacial biofilm penetration after a short-term demineralization period.

The adsorption by biochar can effectively alleviate the problem of ammonia inhibition in biogas engineering. Based on batch adsorption experiments, the effect of acid modifier on physicochemical and adsorption NH4+-N properties of biochar was explored, and anaerobic digestion (AD) with addition of modified biochar (MB) was designed and carried out. The results showed that after modification, the adsorption capacity of biochar was significantly improved, and the maximum adsorbance of MB was 1.57 times higher than that of original biochar. Acid modifier had demineralization and increased the number of acidic oxygen-containing functional groups. Chemical adsorption was the dominant adsorption mechanism, mainly including surface electrostatic adsorption and the interaction between ammonium ions and surface functional groups of biochar. With the addition of MB, gas production rate of the AD of chicken manure was increased and the effective gas production period was shortened to 18 days. This research has guidance significance for alleviation ammonia inhibition during the AD by adding MB.

Objective To evaluate and compare remineralization potential of commercially available calcium sucrose phosphate (CaSP) (5% EnaFix) individually and with 0.2% Sodium Fluoride (NaF) mouth-rinse (ACT Kids Anticavity Fluoride-Rinse) supplementation through Vickers Microhardness tester (VMH) and Quantitative Light Induced Florescence (QLF™) technology on artificial carious lesions on primary and permanent enamel. Materials & methods In present in-vitro comparative study, artificial carious lesions were created on 60 each, permanent and primary enamel samples followed by pH cycling for a period of 21 days with interventional agents (Control; Distilled water; Test; CaSP alone and CaSP + 0.2% NaF). The samples were evaluated for ΔF values of QLF at, demineralization, 7th, 14th and 21st day and VHN at, demineralization and 21st day of pH cycling. The data were analysed using paired t-test and ANOVA. Results Intra group comparison showed the statistically significant fluorescence gain with CaSP+0.2%NaF in permanent samples and statistically significant fluorescence gain with both CaSP and CaSP+0.2%NaF in primary samples (p = 0.001). Inter group comparison of interventional agents in both primary and permanent samples showed statistically non-significant variation between CaSP and added NaF group (p = 0.68). Conclusions Within the limitations of the present study, results showed no significant difference in microhardness improvement and remineralization potential between CaSP and CaSP+0.2%NaF. However, since both showed similar efficacy CaSP looks to be a choice for primary dentition and CaSP with 0.2% NaF can be preferred for mixed dentition with primary and young permanent teeth.

In this study, the removal of monovalent and divalent cations, Na+, K+, Mg2+, and Ca2+, in a diluted solution from Chott-El Jerid Lake, Tunisia, was investigated with the electrodialysis technique. The process was tested using two cation-exchange membranes: sulfonated polyether sulfone cross-linked with 10% hexamethylenediamine (HEXCl) and sulfonated polyether sulfone grafted with octylamine (S-PESOS). The commercially available membrane Nafion® was used for comparison. The results showed that Nafion® and S-PESOS membranes had similar removal behaviors, and the investigated cations were ranked in the following descending order in terms of their demineralization rates: Na+ > Ca2+ > Mg2+ > K+. Divalent cations were more effectively removed by HEXCl than by monovalent cations. The plots based on the Weber–Morris model showed a strong linearity. This reveals that intra-particle diffusion was not the removal rate-determining step, and the removal process was controlled by two or more concurrent mechanisms. The Boyd plots did not pass through their origin, and the sole controlling step was determined by film-diffusion resistance, especially after a long period of electrodialysis. Additionally, a semi-empirical model was established to simulate the temporal variation of the treatment process, and the physical significance and values of model parameters were compared for the three membranes. The findings of this study indicate that HEXCl and S-PESOS membranes can be efficiently utilized for water softening, especially when effluents are highly loaded with calcium and magnesium ions.

Polylactic acid (PLA) matrix composites, reinforced with chitosan microparticles were developed by the compression moulding technique. The chitosan particles were chemically synthesized from crab shell by deproteinization, demineralization and deacetylation processes. The size, functional group, structure and morphology of the chitosan micro particles were determined with the aids of dynamic light scattering particle size analyzer, Fourier Transform Infrared Spectrophotometer (FTIR), X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM) respectively. PLA and various weight fractions (2, 4, 6, 8 and 10 wt%) of chitosan particles were melt-blended by using a HAAKE PolyLab OS Rheomix batch mixer (Thermo Electron Co., USA), operated at a rotor speed of 60 rpm and a temperature of 162 °C for 10 min. The blends were then moulded into different test specimens by using carver laboratory press at a temperature of 190 °C for 12 min under an applied pressure of 0.2 kPa. The mechanical properties (tensile and impact) and wear behaviour of the developed composites were studied. The results showed that there were favourable improvements in the mechanical and wear properties of the PLA matrix composites developed. The optimum values were found at 6 wt% chitosan particles reinforcement for mechanical properties and 10 wt% for wear resistance. The scanning electron microscopic examination of the composites showed that there was a uniform particles distribution at lower weight fractions while particles clustering were noticed on the SEM images at higher weight fractions.

Chitosan is a bio-based polysaccharide having promising biological and antitumor properties. The present study aims at the synthesis of chitosan using shrimp shell waste. Chitosan preparation consists of two consecutive steps such as demineralization and deproteinization. The structure, morphology and optical properties of the obtained chitosan were established using various instrumental techniques like XRD, FTIR, UV–Vis, SEM and TEM. Herein, we have shown that Significant bacterial activity was manifested by chitosan against both gram positive (S. aureus and S. mutans) and gram negative (E. coli and P. aeuriginosa) bacteria. The biosynthesized chitosan exerts an inhibitory effect on the proliferation of MCF-7 breast cancer cells in a dose –dependent manner while being non -toxic to fibroblast L929 normal cells.

Hydrothermal liquefaction (HTL) of fractionated two types herbaceous biomass (kenaf and miscanthus) by dilute acid, organosolv, alkaline, or demineralization process was carried out under ethanol water co-solvent at 350 °C for 30 min to examine the biocrude yield and characteristics. The biocrude properties were comprehensively characterized by HPLC, elemental, GC-MS, and TGA analysis. Fractionation technologies before HTL effectively increased biocrude yield up to 38% compared to that of untreated herbaceous biomass (31%), except for organosolv fractionation of miscanthus, especially, HTL after alkaline fractionation showed high yield and energy recovery ratio up to 70%. Elemental analysis showed that HHV of biocrude was negatively affected by hydrolysis reaction of high lignin content after dilute acid fractionation. The GC-MS analysis revealed that carbohydrates-derived compound significantly increased in the biocrude obtained after organosolv and alkaline fractionation due to holocellulose increases through fractionation process. Additionally, TGA results indicated that the ratio of high-boiling-point compounds in biocrude obtained after demineralization was expanded compared with untreated due to ash removal, which could act as a catalyst.

Biomass is a promising precursor for producing high-performance hard carbon as an anode for sodium-ion batteries (SIBs) because of its high low-voltage plateau capacity. However, the effect of residual ash in biomass on the electrochemical performance of hard carbons has rarely been investigated. This work describes an effective ash-removal approach as a critical step for preparing high-performance anodes for SIBs. A strong correlation between the ash removal techniques with structural and electrochemical properties of hard carbon was revealed. By examining various ash-removal techniques prior to carbonization and after carbonization using aqueous acid, neutral, and alkaline solutions, it was demonstrated that the removal of ash from raw cocoa pod husk (CPH) using aqueous acid and subsequent carbonization at 1300 °C can produce hard carbon with high Na+ ion uptake in the low-voltage plateau region. During the acid pretreatment, ash and some hemicellulose fractions were removed, and carbonization of the acid-treated CPH resulted in hard carbon with a high degree of graphitization and reduced surface area. When tested as an anode in SIBs, the hard carbon produced from the acid-treated CPH exhibited an exceptionally high capacity of 317 mAh g−1 and high plateau capacity of 244 mAh g−1 at 0.05 A g−1, with a high initial Coulombic efficiency of 87%. At a high current density of 250 mA g−1, a high capacity of 134 mAh g−1 was maintained after 800 cycles. Post-treatment of hard carbon did not enhance the electrochemical performance. The physicochemical and electrochemical properties of hard carbons produced with the various pre- and post-treatment techniques were presented.

Recurrent caries is a primary reason for restoration failure caused by biofilm acids. The objectives of this study were to: (1) develop a novel multifunctional composite with antibacterial function and calcium (Ca) and phosphate (P) ion release, and (2) investigate the effects on enamel demineralization and hardness at the margins under biofilms.Dimethylaminohexadecyl methacrylate (DMAHDM) and nanoparticles of amorphous calcium phosphate (NACP) were incorporated into composite. Four groups were tested: (1) Commercial control (Heliomolar), (2) Experimental control (0% DMAHDM + 0% NACP), (3) antibacterial group (3% DMAHDM + 0% NACP), (D) antibacterial and remineralizing group (3% DMAHDM + 30% NACP). Mechanical properties and Ca and P ion release were measured. Colony-forming units (CFU), lactic acid and polysaccharide of Streptococcus mutans (S. mutans) biofilms were evaluated. Demineralization of bovine enamel with restorations was induced via S. mutans, and enamel hardness was measured. Data were analyzed via one-way and two-way analyses of variance and Tukey's multiple comparison tests.Adding DMAHDM and NACP into composite did not compromise the mechanical properties (P0.05). Ca and P ion release of 3% DMAHDM + 30% NACP was increased at cariogenic low pH. Biofilm lactic acid and polysaccharides were greatly decreased via DMAHDM, and CFU was reduced by 4 logs (P0.05). Under biofilm acids, enamel hardness at the margins was decreased to about 0.5 GPa for control; it was about 1 GPa for antibacterial group, and 1.3 GPa for antibacterial and remineralizing group (P0.05).The novel 3% DMAHDM + 30% NACP composite had strong antibacterial effects. It substantially reduced enamel demineralization adjacent to restorations under biofilm acid attacks, yielding enamel hardness that was 2-fold greater than that of control composites. The novel multifunctional composite is promising to inhibit recurrent caries.

Currently, resin composites are the most popular materials for dental restoration in clinical practice. Although the properties of such materials have been improved significantly, together with better clinical techniques used for their placement, early restoration failure still occurs too frequently. As clinical studies take years to complete, and new resin composites are being produced at ever increasing pace, laboratory assessment using accelerated but representative tests is necessary. The main types of failure in resin-composite restoration are tooth/restoration fracture and secondary caries, which are caused by a combination of mechanical and biochemical challenges. In this study, a biofilm model (S. mutans) and a chemical model (lactic-acid buffer) for producing artificial caries in bovine dentin are developed and calibrated against in situ data. Using a power law relationship between the demineralization depth and challenge duration, scale factors that convert the in vitro durations to the equivalent clinical durations are determined for different pH values for each model. The scale factors will allow the synchronization of biochemical and mechanical challenges in terms of their rates of action to potentially test resin-composite restoration in an accelerated but clinically representative manner. STATEMENT OF SIGNIFICANCE: Although the properties of resin composites for dental restoration have been improved significantly, early restoration failure still occurs too frequently. As clinical studies take years to complete, accelerated laboratory testing is necessary. Resin-composite restoration fail mainly through fracture and secondary caries, caused by a combination of mechanical and biochemical challenges. In this study, a biofilm and a chemical model for producing artificial caries in bovine dentin are calibrated against in situ data. Using a power law relationship between demineralization depth and challenge duration, scale factors are determined for different pH for each model. The scale factors will allow the synchronization of biochemical and mechanical challenges in testing resin-composite restoration in an accelerated but clinically representative manner.

In order to promote effective healing of a bone defect, various bone grafts have been widely implanted into defect sites. However, several drawbacks, such as immunologic rejection, insufficient tissue healing, or secondary damage to the donor site, are still concerns. These limitations of the current bone grafts can be overcome by use of a natural ECM that can influence basic cellular behaviors, such as proliferation, migration, and differentiation. Herein, we introduce a novel bone decellularized ECM (bdECM) material extracted from bovine bones via demineralization and decellularization. This sequential process enabled us to prepare raw material possessing higher contents of native BMP-2 and BMP-7, and a fibrous microarchitecture resembling the collagen bundle in the ECM was maintained. Furthermore, residual calcium and phosphate originated from the bovine bone were considerably removed, and contamination by residual DNA was significantly reduced during the fabrication process. These features enabled the scaffold successfully promote mineralization of the cultured primary osteoblasts in vitro, which was significantly better than those from the bone powder or demineralized bone matrix. In a mouse calvarial defect, new bone formation was improved in the bdECM group and the density of those was also higher than other groups.

This work provides methods for chitosan production with larval exoskeletons from Hermetia illucens and characterizes the produced material. The study aims to provide optimal reaction conditions for the purification of chitin from insect material and evaluates the key characteristics of the insect-based chitosan compared to crab shell chitosan. H. illucens is a sustainable source of high-quality protein, lipids and compost currently applied as aquaculture feed and soil improver. The ecdysis of the H. illucens larvae results in larval exoskeletons (LE) rich in chitin and suitable for chitosan production. Using procedures based on crab shell processing, two steps were performed to purify chitin from the larval exoskeletons. The results showed that formic acid is a suitable demineralization agent, requiring 5 mol per kg larval exoskeletons and thorough washing afterwards for 89 % demineralization effectivity (DME). The effect of the deproteinization variables were explored via design of experiments and analyzed using linear regression resulting in chitin contents of the deproteinized material of 83 % in small-scale and 87 % in 10 L-scale, respectively. Heterogeneous and homogeneous deacetylation was performed to convert chitin in different chitosan fractions. Heterogeneous deacetylation at 120 °C resulted in a deacetylation degree (DD) of 72 % and a yield of 43 % at maximum with regard to the total chitin applied. Homogeneous deacetylation at 4 °C resulted in a low chitosan yield of 13 % and a DD of 34 %. However, chitosan solubilized in acetic acid revealed superior film forming properties and a high viscosity. The results indicated that the chitosan from insects has comparable properties than those produced from crab shells, although the properties are also strongly dependent on the manufacturing conditions.

The most abundant polymeric compound in nature after cellulose is chitin. Mostly, it is used as raw material for food additives, agriculture, biomedicine, water treatment, cosmetics and textile industry. Exoskeletons of crustaceans such as lobster, crabs and shrimps, mollusks, insects and the cell walls of certain fungi are the main sources of chitin. The best raw material for the production of chitin is marine exoskeletons. The current objective of this study is to standardize the demineralization process for removal of minerals from the waste of Portunidae segnis (P. segnis) by using chemical treatment. A fix concentration of HCl acid at various reaction conditions are used in the demineralization process for the first step of chitin isolation. The percentage of calcium and phosphorous removed after demineralization process was determined by using sensitive Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The P. segnis was purchased from a local market, it was collected from the coastal area of Oman. The samples were dried and ground into coarse powder. The coarse powdered samples were treated with 2 M concentration of hydrochloric acid at different incubation time, temperature and weight/volume ratio. All treated samples were analyzed by using sensitive ICP-OES. The results from the ICP-OES showed that treatment of P. segnis waste samples with 2 M of HCl at room temperature for 70 min with ratio of 1:20 (w/v) is the best process for demineralization of chitin. FT-IR, SEM/EDX and ICP-OES analysis of this sample confirmed successful isolation of minerals from Omani P. segnis. In conclusion, the best standardized demineralization process could be used for the isolation of good quality of chitin. This chitin could be used as the main raw material in food industry, agriculture, biomedicine, cosmetics and textile industry.

Catalytic coal gasification is an efficient way to achieve high conversion rates at low temperatures. Catalyst loss due to the reaction between the inherent mineral matter in the coal and the catalyst is a major hurdle for its practical application. The problem may be overcome by removing the mineral matter from the coal before use. Two demineralizing approaches, acid-washing and solvent-extraction methods are investigated for demineralizing the coals. Elemental analysis, XRD analysis, NMR analysis, and N2 adsorption analysis were made to compare the demineralization efficiency, crystallographic carbon microstructure, chemical structure, and micro-porosity, respectively. Solvent-extraction method was found be more efficient for demineralization. Difference was observed in the chemical structure and micro-porosity while crystallographic carbon-microstructure was found to be similar. Non-catalytic and catalytic gasification reactivity of the chars obtained by the two methods was compared. Gas composition and gas evolution profiles were also obtained and found to be influenced by the degree of demineralization. Keywords: Coal, Demineralization, Acid washing, Solvent extraction, Catalytic gasification

The cuticle of stomatopod is an example of a natural mineralized biomaterial, consisting of chitin, amorphous calcium carbonate and protein components with a multiscale hierarchical structure, and forms a protective shell with high impact resistance. At the ultrastructural level, cuticle mechanical functionality is enabled by the nanoscale architecture, wherein chitin fibrils are in intimate association with enveloping mineral and proteins. However, the interactions between these ultrastructural building blocks, and their coupled response to applied load, remain unclear. Here, we elucidate these interactions via synchrotron microbeam wide-angle X-ray diffraction combined with in situ tensile loading, to quantify the chitin crystallite structure of native cuticle – and after demineralization and deproteinization – as well as time-resolved changes in chitin fibril strain on macroscopic loading. We demonstrate chitin crystallite stabilization by mineral, seen via a compressive pre-strain of approximately 0.10% (chitin/protein fibre pre-stress of ∼20 MPa), which is lost on demineralization. Clear reductions of stiffness at the fibrillar-level following matrix digestion are linked to the change in the protein/matrix mechanical properties. Furthermore, both demineralization and deproteinization alter the 3D-pattern of deformation of the fibrillar network, with a non-symmetrical angular fibril strain induced by the chemical modifications, associated with loss of the load-transferring interfibrillar matrix. Our results demonstrate and quantify the critical role of interactions at the nanoscale (between chitin-protein and chitin-mineral) in enabling the molecular conformation and outstanding mechanical properties of cuticle, which will inform future design of hierarchical bioinspired composites. Statement of Significance Chitinous biomaterials (e.g. arthropod cuticle) are widespread in nature and attracting attention for bioinspired design due to high impact resistance coupled with light weight. However, how the nanoscale interactions of the molecular building blocks – alpha-chitin, protein and calcium carbonate mineral – lead to these material properties is not clear. Here we used X-ray scattering to determine the cooperative interactions between chitin fibrils, protein matrix and biominerals, during tissue loading. We find that the chitin crystallite structure is stabilized by mineral nanoparticles, the protein phase prestresses chitin fibrils, and that chemical modification of the interfibrillar matrix significantly disrupts 2D mechanics of the microfibrillar chitin plywood network. These results will aid rational design of advanced chitin-based biomaterials with high impact resistance.

Sample storage is of paramount importance in forensic genetics laboratories since only optimal storage enables successful recovery of DNA from old bones that contain very low amount of severely degraded DNA. When identification of missing persons from skeletal remains is completed, bone sample is routinely stored at -20 °C for long-term storage for retesting in future, if necessary. After molecular genetic analyses of Slovenian Second World War (WWII) victims, small fragments of femurs were stored at -20 °C. Reduction in DNA recovery has been observed in frozen liquid DNA extracts by some authors and the goal of our study was to explore how freezing of bone samples affects the preservation of DNA. To achieve this goal, the difference in DNA yield in extracts obtained from WWII bones analyzed in 2009 (data from published paper) and DNA yield in extracts obtained from the same bones (piece sampled next to the one used in 2009) taken out of the freezer after long-term storage on -20 °C for 10 years was examined, using the same extraction method and the same quantification kit. Up to 100 ng DNA/g of bone powder was obtained from 57 WWII femurs and up to 31 ng DNA/g of bone powder from the same femurs investigated after long-term storage in this study. 0,5 g of bone powder was decalcified using full demineralization extraction method. The DNA was purified in a Biorobot EZ1 device (Qiagen) and DNA quantity determined with the Human Quantifiler kit (TFS). Statistical analysis showed significant difference in DNA yield in extracts obtained from WWII bones in 2009 and extracts obtained from the same bones stored at -20 °C after 10 years. As reported for frozen liquid DNA extracts, reduction in recovery of DNA was confirmed for frozen bone samples as well.

Sodium chloride is an effective human corpse tissue preservation medium due to its hygroscopic features and other phyco-chemical characteristics. We present herein sucrose as an alternative material for this purpose. Both media: solid Sodium Chloride and sucrose were tested comparing their efficiency as preservation alternatives. We used a set of 18 phalanges of a female hand buried for over ten year in a sealed coffin. After exhumation, 9 phalanges were preserved in sugar and 9 in salt, individually stored in 15 ml polypropylene tubes at room temperature for 4 years. DNA was extracted by three methods: a- total bone decalcification; b- total demineralization and c- purification by a semi-automated process. Quantification was performed by fluorimetry (F), Plexor (P) and with an “in house” method (H). Amplification was performed with Global Filer and detected in an ABI 3500. DNA yield by method a- (F: 1.36 ± 0.93 ng/ul; P:0.23 ± 0.18 ng/ul) was higher than for b- (F:0,99 ± 0.31 ng/ul; P: 0,14 ± 0.13 ng/ul) or c- method (not detected). Amplification efficiency was determined by the percentage of complete markers (22 loci), the inter-loci balance _ILB-(Shannon Entropy; SH: 3.09 as maximum) and intra-locus balance (mean local balance: MLB). The inter-loci balance was higher for preservation in sugar than in salt (SH: 1.69 vs 1.07) while MLB values did not show significant differences (0.88 vs. 0.89). Degradation ratio correlates with the genetic profile quality. Sugar, as an alternative conservative medium combined with DNA extraction by method a- showed an optimal strategy to obtain good quality genetic profiles.

Dental materials that are antimicrobial and acid-resistant can inhibit bacterial colonization and demineralization, thereby preventing caries. Zinc and copper are well-known for their antibacterial effect, as is nanostructured ZnO–CuO composite. Minerals such as fluorine and calcium, can remineralize and demineralize teeth. Therefore, we developed novel fluoride-containing ZnO–CuO (ZCF) nanocomposites; to the best of our knowledge, these are the first nanocomposites of this kind. The fluoride concentrations and antibacterial effects of the ZCF nanocomposites were evaluated. Nanocomposites comprising zinc and copper (ZC), and zinc, copper, and fluorine (ZCF), were prepared by a simple one-step homogeneous coprecipitation method at a low temperature (80 °C), without the use of organic solvent or surfactant. The structure and composition of the ZC and ZCF nanocomposites were examined by scanning electron microscopy–energy-dispersive spectroscopy (SEM-EDS). Quantitative analysis of the mass concentration was performed by using ZAF correction methods. The fluorine content in nanocomposites was evaluated by using proton-induced gamma emission (PIGE) at the Takasaki Advanced Radiation Research Institute in Japan. By using 96-well microtiter plates, we analyzed the antibiotic susceptibility of ZC, ZCF, and the control buffer (phosphate-buffered saline) with Streptococcus mutans (ATCC 25175). The SEM images showed that ZC and ZCF nanocomposites were composed of 3D flower-like microstructures with diameters of approximately 1 μm. Environmental SEM-EDS analysis revealed that ZC contained 43.2% Cu, 55.1% Zn, 2.2% F, and 0.1% Cl, whereas ZCF contained 47.5% Cu, 40.5% Zn, 6.7% F, and 5.9% Cl. Analysis by PIGE showed that ZCF nanocomposite contained 2553.6 ± 199.2 ppm fluorine, whereas no fluoride was detected in ZC. The control buffer enabled bacterial growth to 4 × 107 ± 9 × 106 CFU/mL, whereas ZC allowed growth of 12 ± 8 CFU/mL, and ZCF showed no bacterial growth. Thus, we developed novel fluoride-containing ZnO–CuO nanocomposites, which exhibited antibacterial effects and have the potential for remineralization, thereby demonstrating their potential as multifunctional dental materials.

Chitin and chitosan have been successfully produced, from Moroccan shrimp shells, using the microwave technology. This efficient extraction method of chitin and chitosan was evaluated and demineralization, deproteinization and deacetylation steps were investigated. The effect of the reaction time, the HCl and the NaOH concentration, at different powers (90 W, 160 W, 350 W, 500 W and 650 W) was studied. The results shown that a chitosan with low degree of acetylation has been extracted using 50% of NaOH solution, at power range 500–650 W, and the deacetylation reaction was more than 80% completed after 10 min. Microwave assisted extraction allowed to produce chitosan with medium and high molecular weight (300–360 kDa). Chitin deacetylation by microwave heating was more efficient than the conventional heating, and high desacetylation degree was obtained using microwave heating in just a few minutes. This technology can save huge amount of energy when implemented on industrial scale, it's a highly economical extraction method. By this technology, we have successfully produced the chitosan CTS with low NaOH concentration (30%), which allows to avoid manipulating an extremely high concentration of a corrosive substance, especially at industrial scale. Chitosan CTS has a degree of acetylation of 23.4% and a molecular weight of 165 kDa.

Hydrocarbon storage and transport in unconventional shale resources occurs predominantly within pores hosted by kerogen (solid and insoluble organic matter in sedimentary rocks). Kerogen-hosted pores are small, so physiochemical interactions between pore fluids and pore surfaces (e.g., adsorption) are particularly important in shale. The understanding and prediction of hydrocarbon storage and transport in shale is dependent, therefore, upon the correct understanding of both chemical composition and pore geometry of kerogen. Several recent studies have attempted to construct molecular models of kerogen physical and/or chemical structure. Developing these models is challenging, in part because of the lack of laboratory samples of kerogen for experimental characterization that preserve both its chemical and microstructural properties representative of those in the subsurface. This study presents an integrated kerogen-isolation procedure that combines closed-system chemical demineralization with pyrite removal and critical point drying. The method produces a kerogen that is not only high in chemical purity but more representative of kerogen microstructure that occurs in the subsurface. Characterization of kerogen microstructure, which can be performed by direct measurement of the isolate obtained by this procedure, is essential to better understand and predict the storage, transport, and production hydrocarbons from unconventional resources.

Surface behavior and structural characteristics of char particles generally play a vital role in affecting char NO emission characteristics during combustion process. A typical bituminous Shenhua from northwest China was employed for demineralization in this research. The demineralized coal without catalytic interference of alkali metal salts was employed as the experimental sample. Moreover, by means of the utilization of isothermal combustion test, Temperature Programmed Desorption (TPD) and Raman spectrometer, the conversion ratio of nitrogen content in char to NO, as well as the evolution of char surface behavior and micro-structure in the process of O2/H2O combustion under different conditions were determined. With the increase of reaction temperature (Tr) and O2 concentration, more surface active sites (Cf), oxygen containing functional groups (C(O)) and small aromatic ring structures generated on char particle surface inhibiting the emission of NO during O2/H2O combustion process. Under identical reaction conditions (Tr, O2 and H2O concentration), the partially oxidized chars with moderate burnout degree (Xc ≈ 0.3) had the largest amount of Cf on particle surface. On the other hand, the amount of Cf and small aromatic ring structures first increased and then decreased as the H2O concentration enhanced. When the Cf amount and the value of I(Gr+VL+Vr)/ID reached the maximum at the H2O concentration of approximately 8.5 vol%, the conversion ratio of char-N to NO reached the minimum value. Meanwhile, the increase of H2O concentration initially accelerated the NO reduction rate and this positive effects gradually diminished when the H2O concentration exceeded the critical value (8.5 vol%). Thus, the optimal combustion condition for char combustion with the lowest NO conversion ratio in this study was: 1473 K, 30% O2 and 8.5 vol% H2O.

Dental caries remains one of the most prevalent bacteria caused diseases affecting both adults and children. It is a dynamic process which progress depends on the interplay between demineralization, caused by the bacteria produced acids from the consumption of sugars, and remineralization that takes place due to the saliva protective qualities/functions. The acids start to dissolve calcium and phosphate from the enamel (demineralization) and at the initial stage, when the tooth damage is not significant, the opposite process – the calcium and phosphate deposition (remineralization) could arrest the caries development thus making the caries a preventable disease. The development of new materials for enhancing the remineralization process is one of the main approaches of the non-invasive dentistry and also one of the main challenges of the advanced dental materials science. In the present study, hybrid chitosan/calcium phosphates microgels were developed for the first time. Their potential and effectiveness as remineralizing agent, enhancing the nucleation and growth of calcium phosphates on a model demineralized enamel surface, was revealed. The hybrid microgels formation was guided by the chitosan macromolecules which acted as a template for the calcium phosphate deposition and resulted into in situ formation of amorphous to poorly crystalline non stoichiometric hydroxyapatite. These newly developed hybrid materials have several advantages as remineralizing agent, including bio-adhesiveness, antimicrobial properties as well as continuous supply of calcium and phosphate ions to ensure the successful remineralization of the model initial caries lesions. Thus, the study reveals a simple and easy to apply remineralization procedure based on the newly developed hybrid materials that could be effectively used for arresting and enhancement of the remineralization of early-stage caries development taking advantage of the night regime of the oral cavity habits. This simple approach has been tested and proved to be effective for remineralization of initial enamel demineralization.

Brackish water (BW) desalination represents an untapped potential for augmenting water resources by the reliable technology of reverse osmosis (RO). There is a significant economic incentive to operate the process at the highest possible water recovery. A high recovery has the important advantage of reducing the amount of concentrate waste stream whose safe disposal is of significant environmental concerns. The degree of RO water recovery possible with a given raw water is dictated by the scaling problem. To overcome this hindrance, a variety of processes have been developed for conditioning the concentrate emanating from the primary RO unit for additional permeate production by a secondary RO unit. This paper provides a critical review of the treatment technologies that enable intensification of the water recovery in BWRO desalination by the intermediate concentrate demineralization techniques. The principles of each technique as well as its strength, weaknesses, technology readiness level, and economics are discussed. Extensive application of ICD technologies requires overcoming challenges such as lowering energy demand and total cost and reducing membrane scaling and use of chemicals.

Objective To evaluate the potential of various alternative milk beverages to support bacterial biofilm formation and acid production and cause unbalanced demineralization. Design in vitro assays were used to examine the ability of the beverages to support Streptococcus mutans’ biofilm formation and acid production from sugar fermentation and the capacity of the beverages to buffer pH changes. Biofilm formation was done using 96-well plate model. Acid production was measured using L-Lactate assay kit, and the buffering capacity was assessed by pH titration. For ex vivo caries model, enamel and dentine slabs and S. mutans biofilms were exposed to selected alternative milk beverages three times a day, 30 min each, and by the end of the experiments, slab’s demineralization was assessed by loss of surface microhardness. Results Of the alternative milk beverages tested in this study, Original Almond consistently supported the most S. mutans biofilms, followed by Chocolate Cashew Milk, while the least biofilms were measured with Unsweetened Flax Milk. The most acids and the lowest culture pH were measured with Toasted Coconut Almond Milk, while the least buffering capacity was measured with Unsweetened Coconut Milk. The results of ex vivo caries model showed that like Bovine Whole Milk, repeated exposure to Original Almond led to significant enamel and dentine slab demineralization, when compared to those exposed to saline as a control (P Conclusions These results further provide support that popular alternative milk beverages, especially those with supplemental sugars, are potentially cariogenic.

Objective This study introduced the potential and proof-of-concept of high intensity focused ultrasound (HIFU) technology for dentin-surface treatment for resin-dentin bonding without acid-aided demineralization. This new strategy could provide a way to enhance interface-integrity and bond-durability by changing the nature of dentin-substrate; bonded-interface structure and properties; and minimizing denuded-collagen exposure. Methods The interaction between HIFU waves and dentin-surface in terms of structural, mechanical and chemical variations were investigated by SEM, TEM, AFM, nano-indentation and Raman-analysis. The bonding between HIFU-treated dentin and two-step, etch-and-rinse, adhesive was preliminary explored by characterizing dentin-bound proteases activities, resin-dentin interfacial morphology and bond-durability with HIFU exposure at different time-points of 60, 90 and 120 s compared to conventional acid-etching technique. Results With the increase in HIFU exposure-time from 60-to-120 s, HIFU waves were able to remove the smear-layer, expose dentinal-tubules and creating textured/rough dentin surface. In addition, dentin surfaces showed a pattern of interlocking ribbon-like minerals-coated collagen-fibrils protruding from the underlaying amorphous dentin-background with HIFU exposure for 90 s and 120 s. This characteristic pattern of dentin-surface showing inorganic-minerals associated/aligned with collagen-fibrils, with 90-to-120 s HIFU-treatment, was confirmed by the Raman-analysis. HIFU-treated specimens showed higher nano-indentation properties and lower concentrations of active MMP-2 and Cathepsin-K compared to the acid-etched specimens. The resin-dentin bonded interface revealed the partial/complete absence of the characteristic hybrid-layer formed with conventional etch-and-rinse bonding strategy. Additionally, resin-infiltration and resin-tags formation were enhanced with the increase in HIFU exposure-time to 120 s. Although, all groups showed significant decrease in bond-strength after 12 months compared to 24 h storage in artificial saliva, groups exposed to HIFU for 90 s and 120 s showed significantly higher μTBS compared to the control acid-etched group. Significance The implementation of HIFU-technology for dental hard-tissues treatment could be of potential significance in adhesive/restorative dentistry owing to its ability of controlled, selective and localised combined tissue alteration/ablation effects.

Ion-exchange membranes (IEM) used in electrodialysis (ED) possess an intrinsic resistance that contributes to the energy consumption of ED treatments. In this work, the performance of cation-coated filtration membranes (CCFM), which are more conductive and less expensive than conventional IEMs, was investigated for the first time on food applications. Four CCFMs (FF50-B3X, FF50-WPR00, FF30-S11 and FF60-S11) were tested for NaCl solution demineralization and two of them (FF50-B3X and FF30-S11) were further tested for whey demineralization in comparison with an AMX anion-exchange membrane, commercially available and currently used in industrial stacks. During NaCl solution demineralization, no significant differences were observed between CCFMs and AMX membranes in terms of demineralization, global resistance and energy consumption. However, during whey demineralization, CCFMs were slightly less effective in terms of demineralization rate (15% less, FF30-S11 only) and energy consumption (both CCFMs): this was explained by the higher roughness and thickness of CCFMs. Furthermore, the overall resemblance in terms of electrochemical characteristics between CCFMs and AMX was in accordance with the results obtained for NaCl solution and whey demineralization. Considering the relatively low electrical energy needed by CCFMs in the overlimiting region, these membranes could also be of interest for ED treatments in overlimiting current conditions. Thus, CCFMs, which are low-cost membranes (40–60 €/m2), could be used for ED at an industrial scale.

The efficacy of using a 45S5 Bioglass paste as a remineralizing temporary filling material was compared to fluoride gel (1.23% acidulated-phosphate-fluoride, Gelato Gel, NJ, USA) applied for 24 h and for 4 min and to a temporary filling material (Caviton; GC, Tokyo, Japan).66 extracted human premolars were used. All specimens were sectioned mesio-distally. All specimens were challenged by a demineralization solution (pH4.5) for 4 days. The specimens were divided into 4 groups: (Bioglass), (Fluoride 4-minutes), (Fluoride 24-Hours), and (Temp) (n = 33). 10 specimens were examined by TMR (Transversal Microradiography)to test remineralization capacity of each agent. 8 specimens were assigned to determine the acid resistance of a bonded resin-enamel interface after the various treatment methods. 15 samples were assigned to determine the effect of each agent on the shear bond strength of a single bottle self-etch adhesive system. One way ANOVA was used to compare the obtained results (p 0.05).Specimens treated with 45S5 bioglass showed statistically significant reductions in (delta z) values when compared to the other three groups (p 0.05). Treatment of demineralized enamel by fluoride prior to bonding significantly decreased shear bond strength values, however 45S5 bioglass treatment did not affect the shear bond strength of adhesive system to enamel (p 0.05). The acid-resistance of the interface between resin-enamel was significantly improved when fluoride or bioglass were applied onto the enamel surface prior to demineralization.45S5 bioglass paste has high potential to be used as a remineralizing temporary filling material.

The aim of this work was to determine how far the effects of micro-osteoperforations (MOPs) extend within bone by quantifying the damage caused and the short-term bony adaptations that occur in and around the injury site.With the use of a split-mouth design, 34 MOPs (Propel) were randomly placed in the mandibular furcal bone of 13 beagle dogs either 2 or 4 weeks before killing them. The control side received no treatment. Vickers hardness microindentation, microscopic computed tomography, and histologic analyses were performed to evaluate the bone surrounding the MOPs.Microfractures produced during insertion extended ∼0.6 mm from the MOP sites. Cortical and trabecular bone were significantly less dense on the experimental than on the control side up to 4.2 mm from the edge of the MOP, but side differences were small (5%) beyond 1.5 mm from the MOP. Experimental cortical bone was significantly softer than the control bone up to 0.8 mm from the MOP after 2 weeks of healing, and up to 0.5 mm from the MOP after 4 weeks of healing. Hematoxylin and eosin stained sections of cortical and trabecular bone showed small areas of woven bone within the MOP sites after 2 weeks, and acellular areas of bone extending ∼0.5 mm from the MOP. After 4 weeks of healing, there were greater amounts of woven bone, as well as early signs of lamellar bone, in and around the MOP sites. Markedly increased TRAP activity extending up to 2.5 mm from the MOP was evident after 2 weeks, but not after 4 weeks. Vital fluorescence staining showed diffuse bone deposition on the experimental side up to 1.5 mm from the MOP margin.When MOPs are performed in beagle dogs, demineralization is transient and healing of the injured area, as well as remineralization of bone affected by MOP placement, begins during the first 2 weeks. Although the transient effects extend farther, the principal effects extend only ∼1.5 mm from the MOP site.

The organic matrix of a bone mainly composed of a collagen matrix serves as a crucial component for remarkable toughness and strength in bones. The porous collagen matrix can also serve as an efficient template for various applications such as nanoparticle synthesis, catalysis or catalysis supports, electrochemical separator, filtration membrane, and tissue engineering. However, fabricating collagen matrix from bones without degrading its morphological structure still remains a challenge. Here, we present evidence of how ceramic crystals from a bone can be removed to fabricate a complete ‘transparent bone’ structure with improved porosity and elasticity. We show that demineralization or selective etching using dilute acid (citric) can remove ceramic mineral nanoparticles without degrading the collagen matrix. The transparent bone collagen matrix is investigated as the separator in electrochemical supercapacitor with aqueous electrolyte where it shows better performance compared with conventional separators.

Untreated corn stalk (CS), deionized water washed CS (WCS), aqueous phase bio-oil washed CS (LCS), and 5% acetic acid washed CS (CCS) were torrefied at 230, 260, and 290 °C. The influences of washing, torrefaction, and combined washing-torrefaction pretreatments on corn stalk pyrolysis were investigated. The combined pretreatments, especially aqueous phase bio-oil washing-torrefaction improved fuel properties of pretreated samples largely by increasing their volatile and hydrogen contents. Absorption peaks of O–H and C O groups in combined pretreatment samples increased when torrefaction temperature increased. In addition, CO, H2, and CH4 contents of pyrolysis gas increased, while CO2 decreased after combined pretreatments. The bio-oil yields from WCS290, LCS290, and CCS290 increased by 134.04%, 127.66%, and 129.79% respectively, compared with that from CS290. Similarly, their relative sugar contents (rich in levoglucosan) increased to 36.63%, 45.89%, and 52.34%, respectively. Aqueous phase oil washing-torrefaction is a promising pretreatment and acetic acid plays the most important role.

OBJECTIVES: Surface conditioning of enamel and dentin is a key step during adhesive restorative procedures and strategies. The aim of this study was to investigate the effectiveness of five α-hydroxy-acids (AHAs) as enamel and dentin surface etchants. METHODS: Enamel and dentin specimens were prepared from human molars to determine the depth of demineralization by optical profilometry (Δz), the resin bond strength to enamel and dentin (μTBS), the micro-permeability of dentin-resin interfaces, and the gelatinolytic activity of dentin matrix induced by AHAs [glycolic (GA), lactic (LA), citric (CA), malic (MI) and tartaric (TA)] and controls [phosphoric (PA) and maleic (MA)]. All acids were prepared at 35% concentration. Adhesion studies employed Adper Single Bond Plus bonding system. Data were individually processed and analyzed by ANOVA, post-hoc tests and Pearson correlations (α=0.05). RESULTS: AHA exhibited statistically lower depth of demineralization of enamel and dentin (average 4 fold) than controls (p

Objectives The objective of the present study was to investigate long-term dentin remineralization via the combination of poly(amido amine) (PAMAM) with a novel rechargeable adhesive containing nanoparticles of amorphous calcium phosphate (NACP). Methods The NACP adhesive was immersed in lactic acid at pH 4 to exhaust its calcium (Ca) and phosphate (P) ion release, and then recharged with Ca and P ions. Dentin samples were pre-demineralized with 37% phosphoric acid, and then divided into four groups: (1) dentin control, (2) dentin treated with PAMAM, (3) dentin with recharged NACP adhesive, (4) dentin with PAMAM + recharged NACP adhesive. In group (2) and (4), the PAMAM-coated dentin was immersed in phosphate-buffered saline with vigorous shaking for 77 days to accelerate any detachment of the PAMAM macromolecules from the demineralized dentin. Samples were treated with a cyclic remineralization/demineralization regimen for 21 days. Results After 77 days of fluid flow challenge, the immersed PAMAM still retained its nucleation template function. The recharged NACP adhesive possessed sustained ion re-release and acid-neutralization capability, both of which did not decrease with repeated recharge and re-release cycles. The immersed PAMAM with the recharged NACP adhesive achieved long-term dentin remineralization, and restored dentin hardness to that of healthy dentin. Conclusions The PAMAM + NACP adhesive completely remineralizes pre-demineralized dentin even after long-term fluid challenges and provides long-term remineralization to protect tooth structures. Clinical significance The novel PAMAM + NACP adhesive provides long-term bond protection and caries inhibition to increase the longevity of resin-based restorations.

Oxy-steam combustion, fuel combusts in O2/H2O atmosphere, is treated to be a novel and promising technology for the next generation oxy-fuel combustion. The purpose of this study is to identify the effects of steam concentration on NO emission characteristics, functional group distribution and char NO reducibility during oxy-steam combustion process. A typical bituminous coal (SH) was employed for demineralization, devolatilization, combustion in O2/H2O environment, and investigated by Temperature Programmed Desorption/Reduction (TPD/TPR) methods and Raman spectrometer. The combustion results illustrated that char N/NO conversion during the oxy-steam combustion tests initially decreased with an increasing steam concentration in low range (1.2–8.5 vol.%), while increased apparently in high steam range (8.5–20 vol.%). Decomposition of H2O molecules promoted the formation of C(O) and small aromatic rings on particle surface at the low steam range; the high concentration of steam could promote the condensation of aromatic ring structures in char, leading to significant generation of large aromatic ring structures with a lower reactivity and the reduction of surface active sites (Cf). The TPD results illustrated that the chars oxidized at moderate steam concentration (8.5 vol.%), and the chars with moderate burnout degrees (such as S3, S6 and S11) had the largest amount of C(O). Due to the decomposition of the C(O) into new Cf and massive CO molecules, a rapid acceleration of NO reduction rate occurred in the temperature range of 1000–1400 K during the TPR process of each sample obtained from identical reaction conditions. Thus, variations in char surface behavior and microstructure might be the primary reasons affecting char-N emission.

Objectives The aim of this study was to evaluate the remineralization effects of conventional and experimental ion-releasing materials on different artificial dentin carious lesions. Methods Forty human dentin discs were submitted to different demineralization protocols for simulated caries lesion: (D1) Shallow chemically-induced caries, (D2) deep chemically-induced caries, (D3) deep bacterially-induced caries. Each disc was divided in five parts; one of those served as baseline control. The remaining parts of each disc (n = 12–16/group) were treated using the following materials: EXP, an experimental resin-based bioactive material consisting of a self-etch primer and an adhesive containing a fluoride-doped bioglass; GIC, a glass ionomer cement (Riva LC); MTA, Mineral Trioxide Aggregate (ProRoot MTA); BIO, a calcium silicate cement (Biodentine). Specimens were mounted in a dual-chamber device to simulate the exposure to pulpal pressure and oral fluids. After 3 months, mineral and mechanical gains were assessed using transverse microradiography (vol% × μm) and microhardness measurements (VHN). Characterization using confocal microscopy and transmission electron microscopy (TEM) was also performed. Results All four restorative materials induced mineral gains regardless of the protocol for caries lesion, without significant differences between materials. Microhardness significantly increased in the groups BIO and MTA, but not GIC; EXP only provided hardness gains in D3-lesions. Fluorescence and confocal microscopy confirmed these results. There was a clear “top-down” remineralization in the groups BIO and MTA, and “bottom-up” intrafibrillar collagen remineralization in EXP. Significance Mineral gains did not always translate into hardness gains. Biodentine and MTA induced evident mineral precipitation, but intra/inter-fibrillar collagen mineral infiltration was only provided by biomimetic remineralisation via the use of the experimental adhesive. Complete remineralization of caries lesions remains a challenge.

Objective This research aimed at monitoring demineralization and remineralization of dentin and its collagen matrix at the nanoscale by amorphous, microcrystalline, and in situ formed hydroxyapatite. Methods The concurrent use of the resonance-enhanced atomic force microscopy coupled with infrared probe (AFM-IR) chemical mapping, nano-indentation, and scanning electron microscopy (SEM) provides a detailed insight into the structure of human dentin, as well as to the processes of its partial demineralization and remineralization. Results The resonance-enhanced AFM-IR chemical mapping of dentin has shown to be a useful method to follow distribution of its collagen and hydroxyapatite components at the micro- and nanoscale levels, especially in conjunction with SEM imaging and nanoindentation. Dentin with a higher extent of natural dentin tubule occlusion tends to be harder and less elastic. The relative affinity of the collagen and hydroxyapatite components of dentin toward hydroxyapatite depends on its type (amorphous, microcrystalline, or formed in-situ). The gel mineralization technique allows for an even and controlled growth of hydroxyapatite guided by the completely demineralized collagen matrix of dentin. Significance The observed trends of the affinity of collagen toward different forms of hydroxyapatite helps develop new remineralizing formulations. The employed methods of characterization may provide an insight to the natural processes of bone mineralization guided by its both hydroxyapatite and protein constituents.

Use of lignite under mild conditions without destroying the natural functional groups and structures is a potential approach for the value-added utilization of lignite. Considering the abundant acidic functional groups in lignite, in this work, a novel and facile route using lignite as robust organic ligands to construct Zr-based catalysts was proposed, and the designed catalysts were applied in the conversion of biomass-derived carbonyl molecules into valuable chemicals. The universality of the proposed route for different rank coals and substrates with various structures were analyzed. Both the preparation conditions of the catalysts and the reaction parameters were systematically investigated. The obtained catalysts were characterized by SEM-EDS, XRD, FTIR, Raman, and TG, etc. The results demonstrated that the designed catalysts were highly efficient for the selective conversion of furfural into furfuryl alcohol. Under the optimized conditions, the conversion, yield, and selectivity were up to 93.4%, 81.0%, and 86.7%, respectively. Both the reaction conditions and the performances of the catalyst were competitive compared with analogous catalysts. It was proved that the catalyst was heterogeneous and the reusability could be improved through demineralization of lignite via acid washing before use, and the catalyst prepared by demineralized lignite had no obvious changes in both performances and structures after 5 reuses. The proposed route was also identified to be applicable for other low rank coals besides lignite, such as long flame coal and coking coal. The catalyst prepared using lignite was robustly effective for the conversion of various carbonyl compounds with different structures, indicating the broad universality for different substrates. Detailed characterization showed that the performances of the catalyst were jointly influenced by both Zr contents and surface areas of the catalyst. This novel route of constructing Zr-based catalysts using low rank coal as raw materials is highly potential for application in the utilization of low rank coals and biomass resources, with the advantages of high efficiency of the catalysts, low cost of raw materials, and simple preparing process.

Bone derives its mechanical strength from the complex arrangement of collagen fibrils (type-I primarily) reinforced with hydroxy-apatite (HAp) mineral crystals in extra- and intra-fibrillar compartments. This study demonstrates a novel approach to obtain organic matrix of bone through its demineralization as well as mechanically characterize it at small length scales using static and dynamic indentation techniques. Sample surface preparation protocol used in the present work maintained the surface integrity of demineralized bone samples which resulted sample surface of roughness (RMS) magnitude of approximately 14 nm (averaged over 1 × 1 μm2 area duly verified by atomic force microscope (AFM)). Elemental composition analysis via energy dispersive X-ray spectroscopy (EDX) (for probed depth upto 2 μm) confirmed the complete removal of HAp mineral from bone samples during their demineralization using EDTA leaving collagen molecule assemblies unaffected as represented by Second Harmonic Generation (SHG) imaging. The modulus magnitudes of organic matrix obtained using from quasistatic as well as dynamic indentations (at constant frequency of 30 Hz) as ∼ 2.6 GPa and 4.5 GPa respectively, demonstrated the influence of loading rate on the estimated mechanical properties. For indentation depth to surface roughness ratio greater than ∼ 5:1, interestingly, measured material properties of organic matrix were found to depend on increasing magnitude of indentation depth of up to ∼ 500 nm value which probed from few collagen fibrils to next level of hierarchy i.e. collagen fibers. These findings are very useful to accurately determine the elastic and visco-elastic response of organic matrices of mineralized tissues for various applications including tissue engineering, bio-mimetics, etc.

For producing demineralized whey concentrates (dry matter (DM) contents: 12–24%) with high whey protein nativity, the suitability of a gentle two-step preservation process (extended shelf life (ESL) process) combining microfiltration and subsequent thermal treatment was investigated. Concentration and demineralization of whey was achieved by using solely nanofiltration (NF) or NF combined with subsequent diafiltration. The influence of the degree of demineralization (number of diafiltration steps: 0; 0.75; 1.5) and DM content on each process step, whey protein denaturation and shelf life of whey concentrates was studied. Applying the ESL process, a strong bacterial reduction of 5.3–7.8 log cycles was achieved depending on the initial bacterial count. For the heat sensitive whey protein β-lactoglobulin, low thermal denaturation of 10–28% was observed, which was independent of DM content and degree of demineralization. However, the shelf life of NF whey concentrates was strongly dependent on their degree of demineralization and ranged between 2 and 16 weeks.

Objective To investigate secondary caries inhibition after dentine pre-treatment with 2% CHX, experimental addition of CHX in primer and adhesive of a 3-step adhesive system, and industrial addition od CHX in a 2-step adhesive system. Materials and method Sixty Class-V cavities were restored according to the adhesive protocol (n = 12): 1) control group, Scotchbond Multi-Purpose, 3M (CTRL), 2) 2% CHX dentine pre-treatment (DENT), 3) 0.1% CHX in primer (PRIM), 4) 0.1% CHX in bonding agent (BOND), 5) Peak Universal Bond including 0.2% CHX (PEAK). Specimens were thermocycled (10,000 cycles) and inserted into a Streptococcus mutans biofilm artificial mouth (caries model). The 10-day biological loading protocol consisted of consecutive phases of demineralisation (1 h) and remineralisation (5 h). Evaluation under a fluorescence microscope (demineralisation) and an SEM (marginal gap) followed, at restoration margins, and at 0.3 mm and 0.5 mm distance from the margins, in enamel and in dentine. Total demineralization was calculated as the sum of demineralisation and substance loss due to demineralisation. Results PRIM (p = 0.007, mod. LSD), BOND (p = 0.012, mod. LSD) and PEAK (p = 0.008, mod. LSD) exhibited significantly higher total demineralisation values in enamel margins than CTRL. No significant differences were noted for total demineralisation in dentine. Regarding marginal gaps, DENT exhibited significantly lower enamel gap values compared to all other groups (p = 0.001). Conclusions 2% CHX as dentine pre-treatment, 0.1% or 0.2% CHX added in adhesives did not provide any antibacterial effect regarding secondary caries in dentine. On the other hand, 2% CHX dentine pre-treatment managed to limit marginal gap formation in enamel compared to the other adhesive protocols in the study.

The use of electrodialysis to treat a low phosphorus-containing solution (0.011 g L−1 HxPO43-x) was evaluated aiming at the recovery of phosphorus from municipal wastewater. The study was held in galvanostatic mode using a five-compartment electrodialysis cell with two pairs of cation- and anion-exchange heterogeneous membrane. A two-stage electrodialysis setup was proposed to recover phosphorus from a low phosphate-containing municipal wastewater. At underlimiting current density conditions, a solution with a phosphate concentration higher than 0.100 g L−1 was obtained by consecutively changing the solution in the diluted reservoir after reaching a demineralization rate of 50.0%. A concentration factor of 9.7 was obtained and no significant changes that could compromise the efficiency of the process were observed. The phosphate ions of the concentrated solution could be then separated from coexisting ions, such as sulfate, by the employment of overlimiting current density conditions, with its feasibility dependent on the use of alkali resistance anion-exchange membranes.

Electrodialysis (ED) with pulsed electric field (PEF) has never been tested on complex food system such as sweet whey. In this study, seven PEF pulse-pause combinations were compared with DC current to assess their impacts on whey demineralization. High-frequency PEF improved the demineralization rate by 81% while reducing the energy consumption by about 16%. This was explained by the emergence of electroconvective vortices (ECV) at the beginning of each pulse due to the appearance of a voltage spike. Since their lifetime are around 0.5 s, these ECV did not have time to fade off during the whole process in the case of high-frequency PEFs increasing consequently the mass transfer. Furthermore, PEF ratio of 1 decreased pH changes and thus could prevent scaling and organic fouling formation. Hence, ED with PEF is a new advantageous energy-efficient approach for the demineralization of whey that could be used in the dairy industries. Industrial relevance This study highlights the beneficial effects of using pulsed electric field (PEF) during ED in comparison to the DC current condition currently used everywhere in industry. First, for the same demineralization rate of sweet whey, PEF requires 16% less energy. This could allow the industries to better deal with the regulatory issues arising from the sustainable development goals. In addition, the use of PEF also prevents the fouling and scaling formation on the membrane, and thus could decrease the load of cleaning agent and the cleaning time required per amount of processed whey. High-frequency PEF such as 0.1 s-0.1 s is a promising greener alternative to conventional ED for demineralization of the million tons of whey generated by the cheese industry every year.

The co-solvent prepared from glycerol and hydrochloric acid (HCl) was used for producing low molecular weight chitin from lobster shell. Different reaction temperature, time and acid concentration were studied. The results suggested that the effect of reaction temperature and acid concentration on molecular weight of chitin is most remarkable. The physicochemical properties of chitins were intact during co-solvent treatment. At least 5% HCl was necessary for demineralization and deproteinization. Low molecular weight chitin could be obtained by increasing reaction temperature, acid concentration and prolonging time. The optimized condition for production low molecular weight chitin was at 120 °C for 2 h with acid concentration of 7% (55 kDa) or at 150 °C for 2 h with acid concentration of 5% (57 kDa). This method provides a fast strategy to obtain low molecular weight chitin with high purity from lobster shell.